Language And Nonsense In Lewis Carrolls Alice Books English Literature Essay

Language And Nonsense In Lewis Carrolls Alice Books English Literature endeavorIm very much afraid I didnt loaded anything merely nonsense. Still, you k straightway, oral communication mean to a greater extent than we mean to express when we expend them so a whole book ought to mean a great passel more than than the writer means. So, what perpetually good kernels are in the book, Im glad to accept as the message of the book.1Many people think Alices Adventures in Wonderland is an example of the limit-breaking book from the old tradition illuminating the naked one. They as well as consider it cosmos a tale. From the looks of it, the story ab go forth Alice falling through a rabbit-hole and get under ones skining herself in a silly and nonsense domain of a function is fairly guileless as a tale.The primal story, the one about a girl maturing away from home in what seems to be a field ruled by chaos and nonsense, is instead a frightening one. Alice finds herself confr onted in dissimilar situations involving various different and curious animals being all alone. She hasnt got any help at all from home or the world outside of Wonderland. The theme with Alice growing and shrinking into different sizes could reflect the ups and downs of adolescence with young people some clippings tinge adult and some measures quite the opposite. One other(a) example of maturing is Alice getting used to the peeled sizes she grows. She dialogue to her feet and learns some of the new ways her body works in. Her feelings are much shaken from her adventures and she cries quite a great deal when its impossible to obey the rules of the Wonderland or is it adulthood? Everything is so out-of-the-way down here, as Alice a good deal repeats to herself.Carroll is an estimable at puns and irony. The part with the sickish tea-party is one of the best examples of this. MAD TEA PARTYTheres a administer of humour in the first Alice book, but in the second the mood gets a bit darker and more melancholic.The quote Everyone in Wonderland is mad, otherwise they wouldnt be down here told by the Cheshire Cat kindle be given an existential meaning. Is it that everyone alive is mad being alive, or everyone dreaming him- or herself away is mad due to the escape from existence? Time is a very central theme in the story. The Hatters vigil shows age because its always six o clock and tea-time. Time matters in growing up, I guess, but further interpretations are left unstate.The first manuscript was called Alices Adventures Underground, and that some at least the Swedish translation of the title is a bit ambiguous, it puzzles more apparent, that the world Alice enters isnt just any childrens playground, but a slenderly frightening and dangerous place for maturing. It becomes more inte confronting when Alice finally gets into the garden and finds a pack of mentalitys ruling it, with a very evil queen at its head. It appears to be a way of truism that the garden isnt really what it appears to be.http//www.alice-in-wonderland.net/explain/alice841.htmlHumpty Dumpty in shapes Alice that there are three hundred and sixty four days when you might get un-birthday presents. His statement is a nonher augmentation to one of the oldest and rudimentary philosophical contr everyplacesies whether Non-Being, like Being, exists.In thecasuistdialogue, Plato argues that what is not in some sense also is, refuting Parmenides concept of the impossibility of the Non-Being to exist. Non-Being is just a being characterised just now by its difference from another being. Carroll was no stranger to Greek philosophy.Carroll is over and over again seen to be fascinated by the idea that Nothingness is more than what meets the eyeTake some more tea, the March Hare said to Alice, very earnestly.Ive had nothing yet, Alice replied in an offended tone, so I angle take more.You mean you cant take LESS, said the Hatter its very easy to take much than nothing. 2The Hatter told Alice that he knew Time and that one cannot talk about wasting it because Time is him. Time, says the Hatter, is someone that if you only knew how to keep on good terms with him, hed do almost anything you liked with the clock, you could keep it to half-past one as long as you liked.3To Humpty Dumpty, as well as to the Hatter, Time is a real entity. Once we become aware of this reality, Platos concept presents no hindrance to the existence of either birthdays or un-birthdays. As with Time, Numbers withal are portrayed by Carroll as real entities. Upon entering the garden Alice comes up to three card gardeners presented by Carroll as Two, Five and Seven. To Carroll, the Christ Church mathematician, Numbers, like Time, are more than just gazump figures they are real Beings. Carroll venerates here Pythagoras concept about Numbers. Aristotle records that the Pythagoreans held that Numbers were the first things in the whole of genius and that the elements of numbers are the elements of all thingshttp//www.alice-in-wonderland.net/school/alice1017.htmlLanguage plays many roles in Alices Adventures in the Wonderland. Carroll illustrates Alices springs of reason, gives her identity and explores rules of conversation.From the commencement exercise of the book, Carroll portrays Alice as a remarkably intelligent little girl, demonstrating this through her verbal argument. After drinking the bottleful and shrinking down to the proper size for entering the garden, she finds she has left the key to the garden on the table, now far above her head. Finding a cake that will likely produce another variety in her size, she decides to eat it. If it makes me grow larger, I can reach the key and if it makes me grow smaller, I can creep under the door so both way minacious get into the garden, and I dont financial aid which happens.4Alice wisely recognizes that any change in size, whether it be smaller or larger, can suit her purpose.Alices power of cerebr ate seem to be inadequate to a little girls character. One could certainly argue that Alices brazen- awardd reasoning as to the advantages of eating the cake is uncharacteristic of a child.However, even while Carroll uses Alices reasoning to become attention to her, he acquisitionfully weaves Alices childish nature into her lyric, as when she announces and I dont care which happens5. Despite her splanchnic reasoning, her speech is still childish. Indeed, Alices reasoning is always stated plainly, as a child might conceivably speak. At the mad tea party, when the Dormouse is telling his story, Alice keeps interrupting. Noting discrepancies in the story that the others seem to overlook, she says But I dont understand. Where did they give suck the treacle from?6Alice has observed that it is difficult to draw something out of a well if you are al assumey in the well, yet the rest of the characters treat Alices questions with impatience. Despite the sense of her questions, they are phrased as a child asking, why? repeatedly, which keeps her in character for a little girl even as she displays her intelligence. In this manner her reasoning stands out from the complexities of the nonsensical Wonderland.Another function of style in Alice in Wonderland is to explore Alices identity. According to Martin Heidegger7, gracious identity is dependents on speech communication. Alice shows evidence of this identity through language. Having found her size so abruptly neutered with eating the cake, she questions if she is still herselfLet me think was I the same when I got up this morning? I almost think I can remember feeling a little different. But if Im not the same, the next question is Who in the world am I? Ah, thats the great puzzle8And she began thinking over all the children she knew that were of the same age as her, to see if she could have been changed for any of them.Carroll also explores the rules or kindly conventions of language. Early in the story, Alic e strikes up a conversation with a mouse. She only succeeds in offending it, however, by talking about catsOh, I beg your pardon cried Alice hastily, afraid that she had hurt the poor animals feelings. I quite forgot you didnt like cats.Not like cats cried the Mouse in a shrill, passionate voice. Would you like cats, if you were me?9 by means ofout her time in Wonderland, Alice learns to adjust her conversation contents to her size, and not offend creatures with reminders of where they rank on the food chain. She demonstrates her new agreement of Wonderlands rules of etiquette during her visit with the Mock TurtleOh, as to the whiting, said the Mock Turtle, they youve seen them, or course?Yes, said Alice, Ive often seen them at dinn she checked herself hastily.10Alice has learned from her previous encounters with Wonderland creatures what is considered offensive by the rules of language, and stops herself just in time from keying that in her world, whiting are food, not frie nds.If any one of them can explain it, said Alice, (she had enceinte so large in the last few minutes that she wasnt a bit afraid of interrupting him,) Ill give him sixpence. I dont believe theres an atom of meaning in it.If theres no meaning in it, said the King, that saves a world of trouble, you know, as we neednt try to find any. And yet I dont know, he went on, spreading out the verses on his knee, and looking at them with one eye I seem to see some meaning in them, afterward all.11The King then proceeds to dissect the poem in order to find its meaning. He is, in fact, analyzing the poem with the interpretation already decided upon a fallacy that is all in like manner easy for an overzealous scholar to commit. Alice, on the other hand, is willing to take the poem at face value as a poem and nothing more thereby displaying the innocence that Sontag so wistfully describes. Using the conflict between the King and Alice, Carroll makes a statement about the danger of exhausti ng to read too much into a work of art.Lewis Carrolls Alice in Wonderland is a great exploration of language. Carroll uses language to confine Alice apart as intelligent, even while he uses simplicity of diction to show that she is still a little girl. Using a mixture of introspection and conversation, Carroll explores the issue of identity, successfully demonstrating that Alices identity through her reasoning abilities, even though she herself doubts who she is. Carroll also plays with the rules of language and how they are learned, by putting Alice in unheard of situations and demonstrating how she learns the new laws of conversation etiquette. Finally, by showing the absurdness of using a poem as criminal evidence, Carroll berates his readers for trying to read too much into his own story. The many roles of language in Alice in Wonderland show Carrolls skill at manipulating words to make his points.http//www.associatedcontent.com/article/13706/the_roles_of_language_in_alice_in_ wonderland.html?cat=38Carroll makes a contrast between the absurdity of the plot and the rationality behind the characters comprehension of Alices language and their literal manipulation of words, phrases, and names. Carroll toys with linguistic conventions in the Through the Looking Glass, making use of puns and playing on multiple meanings of words throughout the text. The author fixs words and expressions and even invents new meanings for words.But even after a sense of the pattern is established, the perceptive use continues to surprise. This method pushes readers to examine the use of language and articulation. Anything is possible in Wonderland, and Carrolls manipulation of language reflects this sense of unlimited possibility.Written in nonsense verse, Jabberwocky is almost a satirical heroic ballad that embodies Lewis Carrolls imaginative language play. The poem creates an altered sense of meaning through invented words. These invented words have English attributes and are simple to read and say, they just do not have meaning outside the context of the poem. he lyrical arrangement, sound of the syllables, and placement in the syntax give many clues as to each words meaning, but no precise definition can be determined. Jabberwocky shows how words void of any meaning in and of themselves can have power, tone, and feeling. After reading it Alice is only sure of one thing, somebodykilledsomething (Carroll 97).Later in the story, Carroll revisits the topic of names and the poem Jabberwocky when Alice meets Humpty Dumpty. Humpty Dumpty, who seems to be substituting words at will, tells Alice he can control of his words as well as their meanings.Shortly before meeting Humpty Dumpty, in chapter four, Alice meets a pair of twin who seem to be mysteriously under the control of language. Tweedledee and Tweedledum are twins who converse in a manner suggesting a difference of opinion as Tweedledee often remarks Contrariwise However that which follows this exple tive doesnt ever seem to be contrary as exhibited when Tweedledum tells Alice I know what youre thinking aboutbut it isnt so, nohow, the other follows adding Contrariwiseif it was so, it might be and if it were so, it would be but as it isnt, it aint. Thats logic (Carroll 114). The recitation of a glasshouse rhyme about the two has predictive powers in Looking-glass world.Words seem to initiate their battle preparations, as if Tweedledum and Tweedledee are predestined by the rhymes she recites, similar to the White Queen telling Alice she remembers things that happen week after next (Carroll 126). The foretold actions and emotions of Tweedledee and Tweedledum illustrate that language can have real power and influence, a message reiterated by the battle of the Lion and the Unicorn.Lewis Carrolls seemingly absurd destabilization of language has the ability to comment on language in society in a unique and simplistic manner. This is exhibited with great ease and admirable form while s eeing Carrolls hilarious characters and situations run a constant discourse on the nature and possibilities of language. He creates a duality in his treatment of language in Alices Adventures in Wonderland and Through the Looking Glass. By splitting words from meanings and names from individuals, Carroll implies an emptiness of words and phrases. However, he also infuses language with the power to create real outcomes and words with power to have several meanings. Language, like life, can aggravate and confuse, but it also contains possibilities that goes unrecognized everyday.http//www.suite101.com/content/properties-of-language-alices-adventures-in-wonderland-a229304In conclusion Carrolls wonderland charters (all adults) are complete mockeries of the adults that Victorian children had to obey.(Hayes, 2) They show the ignorance and absurdity of their time. merely Carroll does show a note of hope. At the end of the first book Alice stands up and expresses her feelings that the whol e mental test is nonsense and that the soldiers were just a pack of cards. In the second book Alice, sick of the chaos and confusion, mobilize the courage to challenge the Red Queen. With these two achievements Alice breaks the spell of the domineering, repressive authority figures(Makinen, 2) and gives hope that in reality this could also be possible.http//www.echeat.com/essay.php?t=25907Meaning, according to Humpty Dumpty Weve had enough of that subject, and it would be just as well if you mention what you mean to do next, as I suppose you dont mean to stop here all the rest of your life.12

The Water Crisis In South Africa

The pee Crisis In southern AfricaSouth Africa is currently facing a urine crisis. Our sources ar scarce and they are constantly being dirty and exploited by unsustainable practices in areas such as agriculture and industry. Unless realistic goals and solutions are utilise to manage the weewee supply, we will become increasingly dependent on obtaining weewee from external sources.Sources of WaterSouth Africas wet resources have always been very limited, and with change magnitude population, the demand for wet has also increased. This puts a lot of strain on South Africas weewee supplies because 65% of the country gets less than 500mm of annual rainfall. This rainfall is inconstant and is practically contaminated by silt and erosion. thither are various areas where South Africa stores and pleonasticcts water. Most of the water we use comes from surface run-off (9 500 million m3/ class of the total of 12871 million m3/year), al close 78.5%. Most run-off from rainfall is held in decameters such as the Gariep dam, the Vaal dam and the Sterkfontein dam. 66% of water in main rivers is not used for economic or social purposes tho remains in the rivers. Another source of water is groundwater held in aquifers. This water is transported by underground underground systems. It jakes also be brought to the surface by digging puff ups or building boreholes. Groundwater supplies about 10% of our national water supply. Because South Africa does not have the resources to supply the countrys water demand, we import extra from Lesotho. This may result in dependency on countries such as Lesotho. Long term plans such as desalinisation of seawater could be used to supply water, notwithstanding solutions such as this nonpareil are very expensive and difficult to do.Availability and DistributionDistribution of water in South Africa is very uneven as thither is a shortage of water in the west but an abundance in the due east. This is due to the warm Mozambican cu rrent that flows along the eastern shore in South Africa, contributing to humidity and heavy rains. The cold Benguela current runs along the west coast reduces the fall of water held in the air. The South Indian heights Pressure is also located along the east coast. The high pressure brings high unions of rainfall to the eastern side of South Africa. The South Atlantic High Pressure also brings rain to the western side of the country but only in overwinter when mid-latitude cyclones are present. These factors cause a huge difference in the amount of rainfall experienced on either side of the country, resulting in rainfall higher than 500mm in the east, and lower than 500mm in the west. Because of this huge inequality, water in South Africa is very scarce and not readily available, causing us to import water from other countries such as the aforementioned Lesotho. Water supply in cities is also lower than in rural areas. For example, in Cape Town, because rainfall is scarce in th e summer and spring seasons, water for internal and industrial use is pumped into the city by underground pipe systems. A lot of the water in South Africa cannot be use as it is either salty seawater or it has been polluted by people, industry and agricultural practices, negatively effecting availability in the country.Usage by Economic SectorsWater is utilized by three main economic arenas agriculture, factories and forestry. In agriculture, which uses 64% of South Africas available water, water is used for irrigation and livestock. Using it for crop farming can be damaging because the water is polluted by chemicals such as insecticides and pesticides. This infiltrates into rivers and groundwater and can reduce South Africas available water resources. 29% is used in factories and manufacturing. This can also be harmful as the water is mixed with poisonous chemicals such as nitrates in the lead being released back into the surroundings. The other 6% of water used in the economi c sector is used in forestry. It is used to irrigate forestry plants for companies such as SAPPI who produce paper and the like, until the forest is well enough established to grow and thrive without irrigation. The water that is used in the economic sector reduces the amount of water that can be used domestically. The water used in these sectors is also often utilized in unsustainable manners, as it returns to the environment containing pollutants. Another economic sector which utilizes water unsustainably is the mining sector. Mine shafts often become flooded and excess water from the mines is released back into the environment containing highly toxic pollutants and sediment from the mines. forethought and SolutionsThere are multiple ways in which water can be used sustainably. bucolic sectors can reduce the amount of fresh water they use by using grey water from areas such as drain pipes to water crops and gardens. Grey water can also be used in toilet systems. The forestry sect or can use sustainable practices such as plant natural trees which use less water than alien species such as gum trees. To conserve water in the household, public messages could be sent out by the government and municipalities to shower instead of bath, and to avoid planting alien species in their gardens, such as roses and pansies. The government could fund new projects such as the wrench of new dams which would be used domestically, in industry, for irrigation and for hydroelectric power. However, this does have a negative aspect to it, as dams are very expensive to build and can often be damaging to the surrounding environment if not designed properly. Another step which could be taken to conserve South Africas water is wetland conservation. Wetlands can regulate pollutants and diseases carried in water. Wetlands reduce erosion, they purify water and they contain bacteria which break down organic fertiliser compounds. They also prevent droughts and floods which saves the gover nment about R21 million. Wetlands also help regulate river flow which is where we get most of our usable water from. Another form of managing water is Water harvesting. This involves collecting rain water during a storm and preventing it from running off. Not only does this prevent erosion, but this water can then be used for agricultural purposes instead of fresh river water. This is a cheap, easy practice which can be enforced on all farms. A simple way to prevent water wastage is by controlling excess losses. These can come in the form of pipe leaks and wasteful irrigation methods. Water pipes should be strictly monitored and regularly checked to ensure that no water is being lost through leakages. Irrigation methods such as canals and nebulizer are unreliable, because while the water is in the canals it can infiltrate into the soil or evaporate before it reaches the crops so extra water has to be used. Spray irrigation is unreliable as the wind can shock absorber the spray away before it reaches the crops. Methods of irrigation such as drip irrigation should be implemented as it is untold more efficientConclusionAlthough water resources in South Africa are currently being over-exploited and unsustainably managed, there are multiple methods of conservation which can be implemented to improve South Africas permanent water supply.

Properties of Dopamine in Chemistry

Properties of Dopamine in chemistryChapter 2. Literature Review2.1 IntroductionIn recent years, natural bond certificate has attracted change magnitude wariness in the material engineering field. This so-and-so be mainly attri notwithstandinged to the oceanic mussel as it has a strong ability to attach to various scrapes in an aqueous environment where they reside. These surfaces vary from natural to synthetic, and inorganic to organic.49-51 Previous studies on the mussel agglutinate protein hold in discovered that 3,4-dihydroxy-L-phenylalanine-lysine sequences, may be the main contributor for the versatile nature of the marine mussel.52, 53 Dopamine, having a similar body structure with this sequence, may provide a unsanded platform for bioengineers to physically or chemically enhance the death penalty of other biomaterials. Several papers gather in already been published regarding the drill of dopamine to augment other biomaterials, such(prenominal)(prenominal) as po ly ( ethyl radicalene glycol), carbon nanotubes and nanofibers. The first part of this review leave alone briefly introduce the basic properties of dopamine which will be fol mortifieded by its applications2.2 Properties of DopamineDopamines properties can be shared out into chemical and adhesive properties. The chemical properties mainly focus on the autopolymerization in aerated basic themes and polymerization of dopamine based on vinyl groups. The adhesive property is dopamines most significant feature which gives dopamine its advantage as a biomaterial.2.2.1 Chemical Properties2.2.1.1 Autopolymerization in Aerated Basic SolutionsMessersmith and coworkers first reported that dopamine is fit to auto-polymerize in aired Tris buffer of pH 8.5.8. The process of dopamine autopolymerization with a pre-existent substrate results in polydopamine (PDA) films organism deposited on the substrate surface. daylong substrate exposure times and high reception temperatures result in thic ker PDA films being formed.54 irrespective of the surface type, the inserted PDA films can be coated on the desired surface, even poly(tetrafluoroethylene) (PTFE), known for its anti-adhesive property.82.2.1.2 polymerisation of Dopamine Based on Vinyl GroupsPolymers carrying pendant dopamine are normally obtained by thoroughgoing polymerization of vinyl monomers with protected or unprotected dopamine. When meditating protected dopamine carried by polymers with double bone, borax (Na2B4O710H2O) is astray apply as the protecting reactant in rank to keep dopamine from forming an annular bidentate catechol subunit.55 Normally, the polymerized reaction of protected dopamine happens in a liquid resolving and forms linear chains. Deprotection reaction usually occurs in an acidic environment and results in the polymer carrying dopamine. Dimolybdenum trioxide56, 1-dromotoluene57 and denzophenone chloride58 can also be roled as protecting agents. Zhang et al.59 knowing a story polym er poly (n-acryloyl dopamine) that possesses high adhesion to wood, especially when mixed with polyethylenimine (PEI) at more or less 150C. They employ a protected double bond dopamine as a monomer and 2,2-azobis(2-methylpropionitrile) as an initiator via revolutionary polymerization, following the deprotection of dopamine in an acid solution. When meditating unprotected dopamine, Lee BP et al.60 was the first to report a germinal hydrogel that copolymerizes modified dopamine with double bond and polyethylene glycol diacrylate via photo initiation by exploitation a 2,20-dimethoxy-2-phenyl-acetonephenone (DMPA) initiator. As a result of this invention, greater attention has been given to hydrogels as a new artificial extracellular matrix (ECM) in the bio checkup field. Dopamine belongs to the catechol family which leads to vinyled dopamine to act as an inhibitor.61, 62, as a result they can react with radicals to inhibit polyreaction. The unprotected dopamine, modified with a vin yl group, is able to undergo free-radical polymerization. Several explorees have done this experiment on radical polymerization to prove the dependability of this method.63-75 The research group led by Metin Sitti, copolymerized a dopamine derivate (dopamine meth-acrylamide) with methoxyethylaceylate to obtain a reversible adhesion on the surface of nonflat glass under dry or wet condition.65 In another publication, 2-(meth-acryloyloxy) ethyl phosphate was used to copolymerize with dopamine methacrylamide, followed by a complicated cohesion in which the copolymer bonded with positively supercharged polymer, divalent calcium and magnesium.71 The chemical properties of dopamine provide the platform of its strong adhesive properties.2.2.2 viscid PropertyThe adhesive property of dopamine is one of the most significant properties of dopamine as it has proven to be very versatile in adhering to various surfaces despite the surface chemistry. The bonding between dopamine and surfaces c an be generally distributed to two parts covalent and non-covalent.10Surfaces which possess amine groups or thiol groups can covalently clog to dopamine via Michael addition or Schiff base reactions. However since most surfaces dont have those groups, non-covalent bonding, equal H-bond, - interaction and benzenediolcharge-transfer compounds are preferred to generate a valid layer and metallic chelating.7, 53, 76-87 In a high pH environment, metal ions and medal oxides have a high chance of being hydroxylated or hydrated, which make chelate with catechol groups of dopamine much easier. This can be seen from many experiments done on polydopamine linking with metal oxides (such as Fe2O3, Fe4O3, ZrO2) through chelating bonding interaction.82, 84, 85 This can be seen when polydopamine nanoparticle suspensions are added to a solution of KMnO4 with H2SO4. A core- example nanoparticle structure is created in which the polydopamine act as the core and MnO2 act as shell, followed by blendi ng the KOH solution to obtain MnO2 nanospheres. This adhesive property of dopamine provides promising opportunities for new bioengineered materials.2.2.3 CNTFor decades, carbon nanotubes (CNT) have been attracting increasing attention because of their superior features, such as thermal conductivity, excellent tensile strength and remarkable conductivity. They have been utilise in various different areas, from sensing elements to catalysis, and from semiconductors to inductors for osteocytes. In order for CNTs to have a wide range of applications, surface modification is necessary. However, during this modification various intermediate reactions steps are required which augment the complexity of the CNTs fabrication. Dopamine modification has been viewed as an promising alternative, leading to a coated multifunctional CNT with a polymeric shell that has tunable thickness by time, pH value and temperature.88 The dopamine surface facilitates the addition of alternate modifications to the surface of CNTs, such as favorable nanoparticles.88 Whats more, CNTPDAs, first, were modified with ATRP initiator and then polymerized with diethylamine methacrylateto to form brushes polymer poly (dimethylamine-thyl methacrylate) (PDMAEMA) on the surface.89 Following that the functionalized CNT were quaternized in order to combine palladium nanoparticles on the CNTs surface. These two examples indicate the potency of dopamine coated CNTs to bind to metal complexes.2.3 ApplicationsThere are many different applications in which dopamine could be applied in three of them will be the focus here including applications in hydrogels, nanofibers, and biosening. These fields are of great by-line currently as they show great promise for dopamine in bioengineering.2.3.1 HydrogelThe need of a steamy hydrogel, as a unique material, is dramatically increasing in various biomedical fields. The high performance requirements of adhesive hydrogels are strict and various. This includes b eing sufficiently adhesive in a wet environment, sufficient elasticity of artificial tissue scaffold and biocompatible.60, 90 Moreover, biomedical hydrogels also need a quick sol-gel mutation for avoiding surgical obstruction. Recently, adhesive hydrogel, inspired by strong wet adhesion of mussel and cross-bonding capabilities of dopamine, has been attracted increasing attention and considered as a hopeful candidate to fulfill this technologic niche.91Messersmith et al.92 reported the creation of four different adhesive hydrogels utilize dopamine differential coefficient (L-3,4-dihydroxyphenylalanine (DOPA)) as end-groups and poly(ethylene glycol) ( reefer) as a backbone. The difference of these four hydrogels can be divided into 2 subcategories, linear network and branched network. They applied multiple-angle laser light scattering to study the influences of different oxidative reagents on DOPA oxidation and hydrogel formation. The result showed that gelation time of PEG-DOPA g els relied on oxidative reagents, such as concentration and type. In Lee H.s report, they also used DOPA and PEG to form hydrogels, but this time they used DOPA modified with methacryloyl chloride and PEG diacrylate instead of pure DOPA and PEG. In order to avoid introducing toxicity of oxidative reagent to the hydrogels and any loss of adhesion, the hydrogels underwent UV initiation.60 These photo-imitated gels demonstrate appreciable elastic properties for use as a promising biomedical material. Using a similar method Phillip B. Messersmiths research group also synthesized an adhesive hydrogel, prepared by copolymerizing DOPA with hydrophobic segments of an amphiphilic block copolymer under photo-imitation. The adhesive property of the hydrogel was surprisingly remediated in the presence of DOPA in wet condition. The elasticity of the hydrogel was run aground to be similar to that of soft tissues leading to consider it as a encouraging candidate for biomaterial.93 advance resear ch conducted by Messersmith and coworkers focused on the biological capabilities of dopamine-PEG adhesive gels. In 2010 they reported that DOPA as end-caps covalently bonded with an amine-terminated 4-arm PEG. The PEG was the core in which oxidative reagents (NaIO4) were added to form an adhesive hydrogel in less than 1 minute.94 The results of the in vivo test, performed in a murine model, showed the adhesive gels caused minimal inflammation and were stably interfaced with the surrounding tissues for more than 24 months. To form a catena degradable adhering polymer, three materials were reacted to form a semblable branched polymer, including dopamine derivative as end-group, PEG and polycaprolactone (PCL) as a backbone.95 These polymers are able to form films whose properties, such as swelling capacity and biodegradation, were bendable by changing the ratio, or concentration of these reactants or by adding other additive agents. After coating these adhesive polymers on a biologic meshes, stronger water system-resistant was exhibited when compared with fibrin sealant or cyanoacrylated polymers.95 Applications for this biomaterial can be prolonged in the surgical field for hernia repair.Stewarts group published several papers about adhesive hydrogels based on complex cohesion. In 2010 they created a bio-mimic hydrogel blending with revised gelatin and a copolymer which is obtained by a dopamine derivative reacting with monoacryloxyethyl phosphate in an alkaline condition.71 The addition of Ca2+ and Mg2+ to the bio-mimic hydrogel could significantly improve the coacervation of the hydrogel, which was applied to tune agglomeration temperature to body temperature. The result show that the cohesion interaction was biodegradable, perfectly suited for medical applications. In another similar research, an adhesive hydrogel was synthesized by complicated cohesion of a positively charged copolymer and a terpolymer involving a dopamine derivative when its pH was higher than 4.70 The bonding property of the hydrogel to hydroxylapatite was around 40% of common cyanoacrylate glue. T.G. Parks group developed a temperature sensitive and injectable tissue-attachable hydrogel.96 The hydrogel was synthesized by conjugating hyaluronic acid and dopamine, following by cross-linking with thiol tail-ended Pluronic F127 via Michael addition. The hydrogel precursor exists at room temperature, and a cured hydrogel is formed when brought to a temperature of 37C. In a later paper, they used a similar strategy forming hydrogel by blending a dopamine derivative modified chitosan with thiol-capped Pluronic F127 at body temperature.97 The adjustable gelation time of this block copolymer made it qualified for tissue-repair at 37C. The resulting hydrogel dedicated excellent in vivo results, where chitosan attend tod as hemostatic agent and dopamine derivative group acted as adhesive agent to soft tissues.2.3.2 NanofiberTissue engineering tends to use nanofiberous bio materials instead of a micropores matrix since the filiform and polyporous nanolevel structure allow for artificial extracellular matrix to enhance the fundamental cellular procedures.98 Nanotechnology reformation have aided in the development of techniques for the production of such a nano-composite materials.Electro-spinning has recently obtained increasing attention, attributing to its briefness and facility for nanofiber fabrication. Through this technique, tough structures are easily tuned in order to coordinate it with the extracellular matrix (ECM).99, 100 So far, this technique has been studied in a range of biological fields, such as bone and skin regeneration.The artificial polymer ECMs usually have difficulties with interfaced reactions between tissues and materials.101 For electro-spinning nanofibers in applications of biomedicine, it is necessary to physically and chemically combine them with biomolecules or cell-recognizing ligands.102 This subsequently provides bio-m odulating or biomimetic micro- environments to contacting cells and tissues. Dopamine coating can be considered as a simple and versatile approach to modify various synthetic polymers so that they are able to serve in biomedical applications.49-51 Ku and coworkers103 firstly reported culturing gay endothelial cells on a polydopamine treated electro-spun polycaprolactone (PCL) nanofiber membrane. They used two control groups, pure PCL nanofibers and PCL nanofibers coated with gelatin, to investigate the ability of cell attachment of dopamine. The result of the water contact angle demonstrated that polydopamine uniformly was coated on the PCL nanofibers. Polydopamine also significantly improve endothelial cells attachment on the nanofiber, compared with other non-adhesive substrates. Moreover, endothelial cells culture on PCL nanofibers coated by dopamine had developed cytoskeleton, positive PECAM-1 and vWF expressions and high cell extend.Rim and coworkers104 designed dopamine funct ionalized electro-spinning poly(L-lactide) (PLLA) nanofibers with minimal influence on its mechanical performances, like wetting capability and roughness. The polydopamine coated PLLA nanofibers significantly enhanced cell attachment and the degree of spread, contradistinguishing with pure PLLA nanofibers. Meanwhile, its fibrous morphology had changed to more of a polygon shape instead of sphere after the polydopamine coating, which lead to higher DNA content of polydopamine treated PLLA nanofibers. The higher gene expressions of cells cultivated on polydopamine treated fibers indicated better osteogenic specialty and vasculogenesis.Extensive research regarding the chemical or physical coating of metal on the surface of scaffolds to increase tensile strength has been done.105 Jungki Ryu et al.106 used dopamine to process hydroxyapatite deposits on PCL nanofiber by coating it. The result demonstrated a combination of surface activation through dopamine coating and hydroxyapatite min eralization allowing the hybridization of various shapes and surfaces. In other reported, Xie and coworkers107 considered dopamine as a superglue, allowing minerals to easily attach to fibrous surfaces. The mechanical properties of mineral functionalized electro-pinning PCL nanofibers, such as stiffness, durability and tensile strength, were near to that of natural bone. Dopamine coated nanofibers show an improvement on existed biomaterials such as their mechanical performances, and cell adhesion. This makes them quite suitable for tissue regeneration and other cogitate bioengineering applications.2.3.3 BiosensingThere is an enormous demand to design highly sensitive and selective biosensors for multiple applications, such as diagnostics, drug screening, and drug discovery.108 Biosensors usually are in the microscale or nanoscale109 and there are legion(predicate) methods to develop them, such as DNA110 and antibody-based sensor111, 112. Scientists employ dopamine in order to opti mize biosensors capabilities which have been reported by several research groups.Lui and coworkers first reported that dopamine could be used in a biosensor.113 They used electricity to oxidize dopamine to form polydopamine on a gold electric pole with existing nicotine. The dopamine-imprinted sensor showed outstanding selectiveness of nicotine and excellent repeatability. Furthermore, Ouyang and coworkers developed a one-step well-defined structure of a dopamine-imprinted sensor.114 They applied electro-polymerization of o-phenylenediamine (o-PD) and dopamine with existing glutamic acid (Glu). By using a potentiostatic time scan, the sensor exhibited satisfactory stereo selectiveness of bonding L- or D-Glu because their relative synthetic receptor. In a different publication, they designed protein imprinted nanowires which dopamine was also involved.115 First, the protein-coupled alumina membrane was immersed in dopamine solution followed by an ammonium persulfate solution in orde r to self-polymerize polydopamine in which afterward the removal of the attached protein is necessary. The nanowires demonstrated constant bonding capability and selectiveness of template proteins due to their cavity structure with bonding spots (like amino group, hydroxyl, - stacking and van der Waals force) that can bind with protein. In another research, Zhou et al. display the creation of magnetic nanoparticles coated by imprinted polymer with a pre-existing template protein.116 The nanoparticles are able to separate target protein from the mixture. In order to investigate the versatility of the imprinted nanoparticles, they operated on a binding test by using five different proteins excluding the template protein. The result indicated that more than 80% of target proteins were rebinding with imprinted nanoparticles, suggesting imprinted nanoparticles have a bright future to be employed for separating and detecting specific protein. matchless of the greatest difficulties for bio sensors is how to immobilize enzymes on the surface of an electric pole and preserve the enzymes functionalities. Wei et al. designed a novel glucose electrochemical sensor, prepared by using a polydopamine film to entrap glucose oxidase and gold nanoparticles.117 Their research displayed a polydopamine matrix embedded with gold nanoparticles that had high efficiency of immobilizing glucose oxidase. The dopamine film embedded gold nanoparticle biosensor showed a superior sensitivity, good repeatability, linear over broad dynamic range and a low detective threshold. Furthermore, in order to assess adaptability of this sensor, they use it to test glucose concentration in attenuated human serum. The result suggested this biosensor is an attractive material for clinical applications

Introduction To Cricket In The 21st Century History Essay

Introduction To Cricket In The twenty- kickoff Century History EssayWhen considering the extensive amount of research that has been tell toward the sporting world from a mathematical, statistical and operational research perspective, the Duckworth/Lewis order (Duckworth and Lewis, 1998, 2004) perhaps stands al champion as the most significant contribution to sport.The viridity practice in dealing with break wholeness-day play harmonisees until 1992 was to compargon the start out a bun in the oven rates (the total number of forces scored divided by the number of undefiled overs) of the competing police squads the group with the higher arc rate was decl bed the winner. However, this rule tended to gain the group at-bat second ( police squad 2) at the expense of the team bat foremost (Team 1), leading to the common practice of inviting the different team to bat first if rain was judge. The difficulty with run rates is that suckers atomic number 18 placed by win ning the carry on overs into account, while ignoring the number of deep in thought(p) wickets. As is well kat oncen, batsmen tend to bat little aggressively and score less runs when more(prenominal) wickets aim been taken. The first team does non have the same(p) strategic options as the second team and, in that sense, the rule does non provide most(prenominal) teams with equal opportunities.Realising that this rule is biased towards the side batting second, the Australian Cricket Board introduced its most productive overs rule during the 1992/93 season. This rule manoeuvres the target for Team 2 by taking the n highest gain ground overs of Team 1 where n is the number of played overs (for example, 40 if 10 overs ar missed receivable to rain). Ironically, this rule was directly considered as tending to favour the side batting first and transparently raw to the team batting second. To illustrate, Suppose that Team 2 requires 20 collide with 19 balls to win, when a scant(p) shower takes deuce-ace overs away. The re trammel target would now be 20 off 1 ball since the three least productive overs are deduced from the original target (which we whitethorn conceive were three maiden overs in this campaign). However, this seems to be unfair and sluice ironical the second teams excellent bowling (three maiden overs) in the first innings is now turning against them it would have been better for Team 2 in this case if Team 1 had reached the same total score without any maidens.The Duckworth/Lewis manner acting was utilised and gained prominence during the 1999 World Cup, and since that time, it has been adopted by every study cricketing board and competition. In one-day cricket, the Duckworth/Lewis system is base on the recognition that at the beginning of a reach, each side has options open (typically 50 overs and 10 wickets). When the match is shortened, the alternatives of one or both teams are reduced and the 2 teams usually have dif ferent imagerys for their innings. In this case, in an attempt to be fair, a revised target for the team batting second is set. The conclusion of the target using resources is known as the Duckworth/Lewis rule. What makes the adoption of the Duckworth/Lewis method funny is that the method is widely perceived by the public as a black box procedure. Generally, people do not understand how the targets are set but they do agree that the targets are level-headed or at least preferent to the move up based on run rates.Although the Duckworth/Lewis (D/L) method was designed for one-day cricket, it has also been applied to Twenty20 cricket. Twenty20 is a relatively in the altogether version of limited overs cricket with still 20 overs per side. In phone line to the one-day game and first-class cricket (which can take up to louvre days to complete), Twenty20 matches have completion times that are comparable to other popular team sports. With the introduction of the biennial World T wenty20 tournament in 2007 and the Indian Premier League in 2008, Twenty20 cricket has gained widespread popularity.Although Twenty20 (t20) cricket is similar to one-day cricket, at that place exist subtle variations in the rules (e.g. fielding restrictions, limits on bowling, etc) between the cardinal versions of cricket. The variations in the rules, and most importantly, the reduction of overs from 50 to 20 suggest that gain patterns in t20 may differ from the one-day game. In particular, t20 is seen as a more explosive game where the ability to score 4s and 6s is more highly valued than in one-day cricket. Since the D/L method (and its associated resource tabularise) is based on the scoring patterns in one-day cricket, it is therefore reasonable to consume whether the D-L method is appropriate for t20.With the rise of Twenty20, an investigation of the D/L method applied to t20 is timely. Up until this point in time, such an investigation major power not have been possible d ue to the dearth of t20 match results. this instant analysts have at their disposal n first 200 international matches, and with and through the expend of efficient estimation procedures, the question may be at least partially addressed. Also, since t20 matches have a shorter duration, to date, few matches have been interrupted and resumed harmonise to D/L. Consequently, if there is a problem with D/L applied to t20, it may not have yet manifested itself. This was true forwards the third editon of the World t20 in May 2010 when a controversial resultant occurred in a game between England and the West Indies. The criticism enjoin at the usage and appropriateness of the method by players, commentators and fans provide commensurate motivation to adjust the skirt in this project.In Section 2, the bend of the Duckworth/Lewis resource add-in is reviewed as well as its effective introduction relative to past rain rules. Some comments are provided on aspects of the control board and the limitations of the method. In Section 3, an alternative Twenty20 resource add-in is obtained using a non-parametric approach based on Gibbs sample. The in initialiseion utilise in the bend of the new remand consist of all international Twenty20 matches to date involving Test-playing nations as recognised by the International Cricket Council (ICC). The project concludes with a short discussion in Section 4. A heat map is provided to aid comparisons between the both hedges.2. For their eyes only Evaluation of the current method and its appropriatenessA condensed version of the Duckworth/Lewis resource table (Standard Edition) is shown in card 1 (taken from the ICC Playing Handbook 2008-09). In an uninterrupted innings of one-day cricket, a team pop ups batting with maximum resources available, equivalent to 50 overs and zero wickets taken. Reflect now on a one-day match where Team 1 scores 276 runs at the end of its 50 overs, as a simple example of the use of the D uckworth/Lewis resource table. Before Team 2 has a chance to start their chase of Team 1s total, it rains and they only receive 30 overs for their innings. A sense of smell at the resource table shows that Team 2 has only 75.1% of their resources in hand and, consequently, their target for winning the match is set at 276(0.751)=208 runs. demarcation the Duckworth/Lewis target with the unreasonably low target of 276(30/50)=166 runs based on run rates. dodge 1. Abbreviated version of the Duckworth-Lewis resource table (Standard Edition)Overs available grillworks incapacitated01234567850 light speed.093.485.174.962.749.034.922.011.94089.384.277.869.659.547.634.622.011.93075.171.867.361.654.144.733.621.811.92566.563.960.556.050.042.232.621.611.92056.654.852.449.144.638.630.821.211.91032.131.630.829.828.326.122.817.911.4517.217.016.816.516.115.414.312.59.413.63.63.63.63.63.53.53.43.200.00.00.00.00.00.00.00.00.0The table entries indicate the portion of resources remaining in a match wi th the specified number of wickets lost and overs available.The D/L method has several advantages, which make it undoubtedly preferable to all previously use retargeting rules completeness (it is able to handle all kinds of interruptions, even multiple interruptions and other unusual situations) the underlying mathematical model is internally consistent tables are intimately accessible/the computer programme is easy and the method compared to previous rules preserves the chance of winning by providing a relatively realistic reset target.Duckworth and Lewis (1998) only make available incomplete information relating to the creation of the resource table. Nevertheless, they do reveal that the table entries are based on the estimation of the 20 parameters Z0(w) and b(w), w=0,,9 check offing to the functionwhere Z(u,w) is the average total score obtained in u overs in an unlimited overs match where w wickets have been taken. While the utility of the Duckworth/Lewis table in one-day c ricket cannot be questioned, a number of questions arise based on (1) and the estimates found in Table 1Is (1) the best flex when considering that there are several parametric curves that could be fit? Is there any benefit in using a non-parametric fit to extrapolate the table entries?The function (1) refers to unlimited overs cricket but is formed from a basis of one-day rules. Since one-day cricket is limited overs cricket, is there an advantage in taking the structure of the one-day game into account?How are the parameters estimated? If the 10 curves corresponding to w=0,,9 are fit separately, there are little data available beyond u=30 for fitting the curve with w=9. Also, the asymptotes for the curves with w=0,1,2 (see Figure 1 of Duckworth and Lewis (1998)) fall beyond the range of the data.In Table 1, the last two columns have many identical entries deprivation down the columns. Although very few matches occur under these conditions, is it really sensible for resources to remain constant as the available overs decrease? This is a solution of the asymptote imposed by (1).Although the D/L method maintains the margin of victory, it does not preserve the probability of victory.The resource table employed by the D/L method, and throughout its several updates, is based on detailed information from a large number of first innings scoring patterns. Therefore, the method assumes that the expected proportion of overall scoring for a particular over when a given number of wickets have been lost is the same in both innings. The validity of this assumption (that scoring patterns are the same in both innings) can be questioned. It has been found that there are a greater relative proportion of runs scored in the early and late overs of second innings, than in the first innings.The rule assumes that run-scoring accelerates right from the beginning of the innings so that runs come at a faster rate for every over completed an exponential function relationship between runs and overs is assumed. Although this captures the fact that run-scoring accelerates at the end of an innings, the moment of stabilization somewhere after the relaxing of fielding restrictions is overlooked. 50 overs has been the standard format for a One-day International (ODI) for so long (over 20 years) that there is a period between the end of the fifteenth over and the start of the forty-first where the batting side keep up the scorecard ticking over through nudged and nurdled singles whilst the fielding side are perfectly happy to concede.Furthermore, no consideration is given to powerplay overs in which fielding restrictions are in place. Losing two overs during a period of fielding restrictions reduces a teams resources more than when a team loses the same couple of overs somewhere between, say, overs 25 and 30. The D/L method does not reflect the fact that the first period has a lots higher run-scoring capacity than the second.The asymmetry between the equations for r esetting targets impairs the quality of impartiality and may even lead to strategic options which are not equally spread out to both teams. When the target is large and Team 2 forsees a essential reduction of its innings, Team 2 could take the strategic option to keep as many wickets as possible in hand, even if the scoring rate is less than required a score of 99/1 (or 110/2, 123/3) after 25 overs in the second innings against a target of 286 for 50 overs would win if no further play is possible. This perverted result is not merely due to the scaling of limited early data but also stems from an idealised assumption of how batting sides position their resources during an innings.The D/L method, like other (target) prediction algorithms, tries to fit historic data into a function curve, and uses this to predict future match states. Although this approach is generic and scales well, the specificity of the match is lost. For example, say in two instances a match is interrupted in t he first innings with the score at 100/3 after 25 overs. The prediction (extrapolation) for both the matches will be the same. However, if one of the teams were 90/0 after 15 overs and the other team were 40/3 at the same stage, it is highly probable that the second team would have gone on to score more than the first.3. Turn the tables A new model for Twenty20 matchesFor ease of discussion, it is convenient to convert the Duckworth/Lewis resource table to the con schoolbook of Twenty20 the resource table is shortened to 20 overs and the entries scaled so that an innings beginning with 20 overs and zero wickets corresponds to 100% resources. Table 2 gives the total Duckworth/Lewis resource table (Standard Edition) for Twenty20 where the entries are obtained by dividing the corresponding entry in Table 1 by 0.566 (the resources remaining in a 1-day match where 20 overs are available and zero wickets taken).Table 2. The Duckworth/Lewis resource table (Standard Edition) scaled for Twe nty20Overs availableWickets lost01234567820100.096.892.686.778.868.254.437.521.31996.193.389.283.976.766.653.537.321.01892.289.685.981.174.265.052.736.921.01788.285.782.577.971.763.351.636.621.01684.181.879.074.769.161.350.436.220.81579.977.975.371.666.459.249.135.720.81475.473.771.468.063.456.947.735.220.81371.069.467.364.560.454.446.134.520.71266.465.063.360.657.151.944.333.620.51161.760.459.056.753.749.142.432.720.31056.755.854.452.750.046.140.331.620.1951.851.149.848.446.142.837.830.219.8846.645.945.143.842.039.435.228.619.3741.340.840.139.237.835.532.226.918.6635.935.535.034.333.231.429.024.617.8530.430.029.729.228.427.225.322.116.6424.624.424.223.923.322.421.218.914.8318.718.618.418.218.017.516.815.412.7212.712.512.512.412.412.011.711.09.716.46.46.46.46.46.26.26.05.7The table entries indicate the constituent of resources remaining in a match with the specified number of wickets lost and overs available.To build a resource table for Twenty20 (t20), it is imperative to consider the scoring patterns specific to the shortest version of the game. Hence, consider the 141 international t20 matches involving ICC full member teams that have taken place from the first in 17 February 2005 through to 14 January 2011 (details of these matches can be accessed from ESPN Cricinfo). The shortened matches where the Duckworth/Lewis method was present have been excluded on with the t20 matches involving non-test playing nations (ICC Associates) the latter disqualification is in place to ensure matches are of a consistently high standard.Since scoring patterns in the second innings show a level of dependency to the number of runs scored by Team 1, consider first innings data only in the examination of t20 scoring patterns. invoice that in their development of a simulator for one-day cricket match results, Swartz et al (2009) consider batting behaviour in the second innings. Match summary results are getable from ESPN Cricinfos statistics website but this study calls for ball-by-ball data. For this, Stephen Lynch (statistician) took pains to compose the associated commentary pound for each match and store the data in a tabular form for easy access.For each match, define z(u,w(u)) as the runs scored from the point in the first innings where u overs remain and w(u) wickets have been taken until the conclusion of Team 1s innings. Calculate z(u,w(u)) for all values of u that occur in the first innings for each match beginning with u=20 and w(u)=w(20)=0.Next calculate the matrix T=(tuw) where tuw is the estimated percentage of resources remaining when u overs are available and w wickets have been taken. Calculate (100%) tuw by averaging z(u,w(u)) over all matches where w(u)=w and dividing by the average of z(20, 0) over all matches the denominator is the average score by a side batting first in a t20 match. In the case of u=0, set tuw=t0w=0.0%. Table 3 displays the matrix T, an initial attempt at a resource table for t20. Note that t20,0=100% as desired . Although T is a non-parametric estimate of resources and makes no assumptions concerning the scoring patterns in t20, it is less than ideal. First, there are many table entries where there are scatty data for the given situation. In addition, Table 3 does not exhibit the monotonicity expected. Logically, there is a requirement for a resource table that is non-decreasing from left to right along rows and a requirement for a resource table that is non-decreasing down columns. Also observe some clamant entries in Table 3, particularly the entry of 110.2% resources corresponding to 19 overs available and two wickets taken. This entry is clearly misleading and should be less than 100%. It arises due to the small take in size (three matches) corresponding to the given situation. For this non-parametric resource table (upcoming), the estimation procedure is robust to observations based on small sample sizes as the surrounding observations based on larger sample sizes have greater infl uence in the determination of the table. Therefore, there is retention of conspicuous observations such as 110.2%. This investigation of Duckworth/Lewis in Twenty20 should be viewed as one of discovery rather than an attempt to replace the Duckworth/Lewis table.Table 3. The matrix R=(r ow) of estimated resources for Twenty20Overs availableWickets lost01234567820100.01993.683.0110.21890.485.878.31786.780.582.853.71681.774.581.970.732.81576.571.471.565.959.91468.369.167.666.258.41363.868.262.462.959.024.31262.162.360.657.358.844.11160.556.357.053.661.039.71057.649.652.152.848.138.641.035.2954.952.143.649.044.133.835.029.7851.046.441.742.241.236.727.528.7748.645.838.935.939.134.824.125.5654.037.936.630.336.231.320.921.426.7544.032.525.428.729.423.917.114.9428.223.422.522.220.914.310.6320.619.916.917.815.812.47.6221.217.611.913.410.611.07.218.75.27.36.05.56.0The table entries indicate the percentage of resources remaining in a match with the specified number of wickets lost and overs av ailable. Note Missing entries correspond to match situations where data are unavailable.To impose the monotonicity constraints in the rows and columns, refer to the general problem of isosmotic regression. For these purposes, consider the minimisation ofwith compliance to the matrix Y=(yuw) where the double summation corresponds to u=1,,20 and w=0,,9, the quw are weights and the minimisation is publication to the constraints yuwgreater than or equal toyu,w+1 and yu,wgreater than or equal toyu1,w. In addition, impose y20,0=100, y0,w=0 for w=0,,9 and yu,10=0 for u=1,,20.Although the fitting of Y is completely non-parametric, there are some arbitrary choices that have been do in the minimisation of (2). First, not only was the choice of squared error discrepancy in (2) convenient for computation, minimisation of the function F with squared error discrepancy corresponds to the method of restrict maximum likelihood estimation where the data ruw are independently usually distributed with representation yuw and variances 1/quw. Second, a matrix Y 20 10 based on overs is chosen. Alternatively, a larger matrix Y great hundred 10 based on balls could have been considered. The overs formulation is preferred as it involves less missing data and leads to a less computationally intense optimization. With a matrix Y based on overs, it is possible to change on a ball-by-ball basis if required. Third, a simple choice has been made with respect to the weights quw. 1/quw is set equal to the sample variance used in the calculation of ruw divided by the sample size. The rationale is that when ruw is less variable, there is stronger belief that yuw should be close to ruw.Table 4 gives a non-parametric resource table based on the minimisation of (2). An algorithm for isotonic regression in two variables was first introduced by Dykstra and Robertson (1982). Fortran code was afterwards developed by Bril et al (1984). An R code implementation has been used that is availabl e from the Iso package on the Cran website (www.cran.r-project.org). The programme requires 27 iterations to achieve convergence. What is unacceptable about Table 4 is that it suffers from the same criticism that was directed at the Duckworth-Lewis resource table. There is a considerable number of bordering entries in Table 4 that have the same value. Again, it is not sensible for resources to remain constant as available overs decrease or wickets increase. The problem is that in the minimization of (2), various fitted ys occur on the boundaries imposed by the monotonicity constraints. Table 4 is also unsatisfactory from the point of view that it is incomplete missing values correspond to match situations where data are unavailable.To address the higher up criticisms, it is necessary take a slightly different approach to estimation. As previously mentioned, it can been seen that (2) arises from the normal likelihoodTherefore, consider a Bayesian model where the unknown parameters in (3) are the ys. A flat indifference prior is assigned to the ys subject to the monotonicity constraints. It follows that the posterior density takes the form (3) and that Gibbs have can be carried out via sampling from the full conditional distributionssubject to the local constraints on yuw in the given iteration of the algorithm. Sampling from (4) is easily carried out using a normal generator and rejection sampling according to the constraints. Although in statistical terminology, (3) takes a parametric form, the approach is referred to as non-parametric since no functional relationship is imposed on the ys.Table 4. A non-parametric resource table for Twenty20 based on isotonic regressionOvers availableWicket lost01234567820100.01993.685.585.51890.485.580.81786.780.880.864.71681.777.477.464.755.91576.571.571.564.755.91468.868.867.664.755.91366.666.662.662.655.938.41262.262.260.657.355.938.41160.556.856.854.854.838.41057.652.152.152.148.138.434.129.3954.952.146.546.544.136.3 34.129.3851.046.442.042.041.236.328.628.6748.645.838.937.337.334.825.325.3639.739.736.632.832.831.323.021.421.4539.732.528.028.028.023.017.115.5427.923.422.522.220.914.310.7320.719.917.417.415.812.47.7220.717.612.512.510.810.87.218.76.66.66.05.75.7The table entries indicate the percentage of resources remaining in a match with the specified number of wickets lost and overs available. Missing entries correspond to match situations where data are unavailable.In Table 5, the estimated posterior means of the ys obtained through Gibbs sampling are given, and these provide an alternative resource table for t20. The computations pose no difficulties and the estimates stabilize after 50,000 iterations. For cases of missing data, the Duckworth/Lewis table entries are used to impute the missing rs. The imputation is in the spirit of a Bayesian approach where prior information is utilised. Unlike Table 4, Table 5 is a complete table. Also, there are no longer adjacent table entries with identi cal values and this is due to the sampling approach. Finally, it can be stated that the methodology allows the input of undecomposed opinion. For example, suppose that there is expert consensus that a table entry yij ought to be tied down to a particular value a. To force this table entry, all that is required is to set rij=a and assign a sufficiently small standard going away Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact emailprotected or the rootageTable 5. A non-parametric resource table for Twenty20 based on Gibbs samplingOvers availableWickets lost01234567820100.096.993.087.981.372.259.944.829.71995.690.987.783.076.968.356.542.027.21891.7

Case Study: Methanol Poisoning of a Child

Case Study methyl intoxicant Poisoning of a ChildIntroductionIn this PBL, we observe a case of m ethyl intoxicant poisoning in a child. We will scratch line define the unfamiliar term of tertiary wish marrow and restrain to understand acidulent base homeostasis in the body, the basis for wood spirit poisoning. and so we will look at how ethyl alcohol and wood spirit be metabolised in the body fol pocket-sizeded by how methyl alcohol poisoning actually field of studys. We will to a fault discuss how the osmolal gap is obtained victimization osmolality and osmolarity and functionly child abuse.Learning Objectives interpretation of unfamiliar terminologyAn overview of acid base homeostasis in the bodyHow ethanol and wood alcohol be metabolised in the bodyHow does wood spirit poisoning work atOsmolality and osmolarityChild abuse1. Unfamiliar term Tertiary care fondnessA tertiary care centre is where a patient goes to when principal(a) and secondary care occupy no n been able to adequately action the patient. Tertiary care centres are equipped with spiritedly trained impart and exaltedly dedicated medical equipment to cater to complex treatments or procedures as required by the patient. An example of a tertiary care centre would be the colorectal unit at The Royal London (1). Amareen was transferred to a tertiary care centre to receive more suitable care mainly imputable to the fact that she was so young and suffering from methanol poisoning.2. Overview of acid base homeostasis in the bodyAcid base homeostasis is the statute of hydrogen ions. The luxuriouslyer the tightness of hydrogen ions, the lower the pH and wrong-doing versa. Acidic solutions have a full(prenominal) pH whereas alkaline solutions have a lower pH. The public pH in the body is in the range of 7.35-7.45. A pH lower than 7.35 results in acidosis whereas a pH higher(prenominal) than 7.45 results in alkalosis.Acid base balance has its basis in the Henderson-Hasselbal ch equation shown in Figure 2. If we rearrange the equation, we see that bi nose candyate and nose candy dioxide directly affects the acid base balance.Figure 2 Henderson-Hasselbalch Equation (3) there are three main moods in which the body controls the acid base balance. These three systems unremarkably work together. Firstly, there are physiological moderates, each of which consist of a weak acid and its base saltiness or a weak base and its base acid. Physiologic buffers move immediately within seconds to the change in pH in the body. These buffer systems occur in twain intra and extracellular parts of the cells. The main buffering systems for physiologic buffers are extracellular bicarbonate-carbonic acid buffering system, intracellular protein buffers and phosphate buffers in the bone. An overview of the physiologic buffer system is shown below in Figure 1.Figure 1 Physiologic buffer systems (2)If physiologic buffers are not enough to birth the pH back to its normal value, pulmonary compensation can guide on place in the lungs. This works by eliminating or retaining carbon dioxide. increase ventilation effort (hyperventilation) and decreased ventilation effort (hypoventilation) are the cardinal ways pulmonary compensation works. The changes in pulmonary compensation is fast within a few proceeding.The final compensatory mechanism, renal compensation in the kidney, starts when the previous two mechanisms have failed to regulate the pH level in the body. The kidneys maintain balance by excreting or conserving bicarbonate and hydrogen ions in the body. However, this compensatory mechanism is a long term regulator and takes longer, usually a few hours, to respond to a change in acid base balance.The normal arterial course gas values for incomplete pressure of carbon dioxide is 35-45 mmHg/ 4.7 kPa-6.0 kPa and bicarbonate soaking up is 22-26 mmol/L. A change in the partial pressure of carbon dioxide or bicarbonate concentration from normal leve ls results in respiratory or metabolic disorders respectively. This together with acidosis or alkalosis refractory by the pH results in 4 main disorders arising. Figure 3 below shows the 4 different disorders and their respective compensatory mechanisms.Figure 3 diagnosis of the quadruplet main acid base disorders and respective compensation mechanisms (4).In Amareens case, metabolic acidosis occurs. The major cause is the high production of formic acid which is not excreted quickly from the body. This has caused a decrease in the bicarbonate concentration overdue to H+ combining with bicarbonate. By the law of hand action using the Henderson- Hasselbalch equation, there is extra CO2 generated therefrom Amareen shows respiratory compensation via tachypneic breathing whereby the peripheral chemo receptors in the lungs are stimulated which stimulates the alveoli to turn in to exhale the excess CO2. The exhalation of CO2 would in most cases be enough to correct the metabolic aci dosis but in this case as methanol was ingested, external treatment was mandatory to save Amareens life.3. How methanol and ethanol are metabolised in the bodyEthanol metabolismEthanol, unremarkably known as drinking alcohol, is metabolised primarily by alcohol dehydrogenase in the liver. Once ingested, ethanol is quickly clothed by the gastrointestinal booklet and small intestines with concentrations reaching at maximum level at 20-60 minutes (5). Ethanol is metabolised to acetaldehyde by alcohol dehydrogenase and then to acetate in the mitochondria via aldehyde dehydrogenase. Acetate is then metabolised to Acetyl CoA and subsequently to CO2 and H2O by the Krebs cycle in the mitochondria. Ethanol can also be metabolised by two other pathways by cytochrome P450 2E1 (CYP2E1) in microsomes of the endoplasmic reticulum when there is a high ethanol consumption and by catalase in peroxisomes (6). The three ways ethanol is metabolised are illustrated in Figure 4 below.Figure 4 Oxidativ e pathways of ethanol metabolism in the body (7)Methanol metabolismMethanol, commonly known as wood alcohol, can be absorbed by the body via inhalation, ingestion and skin exposure (8). In this item case, Amareen ingests methanol. When methanol is ingested, it is quickly absorbed by the gastrointestinal tract with concentration reaching a maximum level at 30-90 minutes by and by ingestion (8). Methanol is primarily metabolised in the liver. In the first step, methanol is metabolised to formaldehyde by alcohol dehydrogenase. Then formaldehyde is subsequently metabolised to formic acid by formaldehyde dehydrogenase. formic acid is finally metabolised into carbon dioxide and water in the presence of tetrahydrofolate. This final step proceeds very slowly and hence there is an accumulation of formic acid in the body which is the chief cause of methanol poisoning and will be discussed in the next section. Methanol metabolism is illustrated in Figure 5 below.Figure 5 Metabolism of meth anol (9)4. How does methanol poisoning workSymptoms and CausesThe main characteristics of methanol poisoning are metabolic acidosis and ocular damage. Formic acid, the metabolite of methanol and not methanol itself is considered to be toxic. The severity of the toxicity correlates with the grade of metabolic acidosis rather than concentration of methanol. (10, 11) The accumulation of formic acid in the body has many detrimental effects if left untreated. The effects of methanol poisoning can be grouped into different phases (12). The phases are exposit in Table 1 below.Table 1 Different phases of methanol poisoningFormic acid has been shown to inhibit cytochrome C oxidase activity in mitochondria (14) which is similar to the action of cyanide, hydrogen sulphate and carbon monoxide (15). Cytochrome C oxidase is the last enzyme in the electron transport chain of the mitochondria which results in the synthesis of adenosine triphosphate (16). Thus, by inhibiting cytochrome C oxidase, there would be significant reduction in the synthesis of ATP resulting in cell hypoxia leading to cell wounding and death (17, 18).The amount of formic acid in the blood is relative to the increase in the anion gap which measures the contribution of unmeasured anions to acidosis by using the formula Na+ + K+ Cl- HCO3- (19). A high anion gap of 20mmol/dL was observed in the arterial blood gas of Amareen when she was transferred to the tertiary care centre. A high anion gap indicates the loss of bicarbonate ions without con actual loss in chloride ions. Thus, a low serum bicarbonate level is a reliable index of the severity of methanol poisoning. Other causes of a high anion gap are diabetes keto acidosis, lactic acidosis, ethylene glycol and salycilate.DiagnosisDiagnosis for Amareen was relatively comfy as a history was available from her parents stating that she had ingested methanol. This allowed doctors to treat Amareen quickly and powerful to prevent blindness or even deat h. If a history is unavailable, a test for the osmolal gap (refer to on how osmolal gap is derived) is very useful. A high osmolal gap (10 mOsm/kg H20) indicates the presence of significant amounts of low molecular encumbrance substances such as methanol. When methanol is metabolised, the osmolal gap returns to the normal and the anion gap increases due to formic acid formation which causes bicarbonate ions to decrease via the Henderson Hasselbach equation.A high serum methanol concentration of 35 mg/dL ( 0mg/dL), low serum bicarbonate level of 18mmol/L, low pH of 7.32 and a high anion gap of 20mmol/dL confirms Amareens diagnosis of metabolic acidosis cause by methanol poisoning.TreatmentsIn this case, Amareen is treated with an ethanol drip. This is because like methanol, ethanol uses alcohol dehydrogenase as its first stage of metabolism and that ethanol has a higher affinity for alcohol dehydrogenase than methanol in the ratio of 201 (8). Therefore when ethanol enters the bloods tream, they will competitively bind to alcohol dehydrogenase thus inhibiting the formation of formic acid. In a clinical setting, a head level of 100-150 mg/dl is used to saturate alcohol dehydrogenase with ethanol (20). However, ethanol can be a challenge to administer due to irregular rate of metabolism making a steady posterior level difficult to maintain and it can also cause insobriety (20).Amareen later receives fomepizole treatment after the ethanol drip was not so effective. This is a better treatment because fomepizole has an even higher affinity for alcohol dehydrogenase than methanol in the ratio of 80001 (21). This prevents methanol from being metabolised. The advantages of fomepizole are the ease of administration, long duration of effect and that it doesnt cause crapulence (22). However, fomepizole is very expensive and is less widely available (23).Due to both ethanol and fomepizole being ineffective in reducing the serum concentration of methanol in the body, hae modialysis was started. Haemodialysis is the most effective way to remove methanol and formic acid from the body (24). This works by passing blood from the body through a dialysis machine that contains a series of membranes to filter out unwanted substances and replenish essential minerals to the blood and then pumping blood back to into the body. The reason why haemodialysis was not immediately administered was probably due to it requiring a neck line which is very invasive and can result in multiple complications for Amareen who is only 5 years old.5. Osmolarity and OsmolalityOsmolality refers to the osmolar concentration of plasma per kilogram of solvent. Osmolality is measured using osmometers. Osmolarity on the other hand refers to the osmolar concentration of plasma per litre of solution. This value is work out using a set formula from measured concentrations of Na+, K+, glucose and urea. The equation is 2Na+ + 2K+ + Glucose + Urea (all in mmol/L). Using osmolality and osmola rity, the osmolal gap can be calculated which is the difference between the actual osmolality and the calculated osmolarity which normally lies in the range of 8-10 mOsm/kg (25).6. Child AbuseThere are four main categories of child abuse (26). Physical abuse which involves bodily disparage for example bruises, burns and fractures. Emotional abuse that involves persistent aroused ill-treatment or neglect causing adverse effects on the childs emotional development. Sexual abuse by forcing a child to perform knowledgeable activity. This includes non-contact sexual activities such as producing child pornography. Lastly, negligence which is the failure of carers to provide the basic physical and psychological needs as well as supervision from harm to the child which results in an adverse effect on the childs health and development. An example would be protecting a child from dangerous substances which Amareens parents have failed to do.ReferencesNHS. Barts Health General operation f or patients NHS 2014 cited 2014 11 November. Available from http//www.bartshealth.nhs.uk/our-services/services-a-z/g/general-surgery/for-patients/.College AC. Electrolyte legato Balance Austin community College 2014 cited 2014 11 November. Available from http//www.austincc.edu/apreview/EmphasisItems/Electrolytefluidbalance.html.Keener P. Okeanos Explorer expeditiousnesss INDEX 2010 Indonesia-USA Deep-Sea Exploration Expedition Purpose 2014 cited 2014 11 November. Available from http//oceanexplorer.noaa.gov/okeanos/explorations/10index/background/edu/purpose.html.Droual R. The Urinary System Fluid and Electrolyte Balance Modesto Junior College 2014 cited 2014 11 November. Available from http//droualb.faculty.mjc.edu/Course%20Materials/Physiology%20101/Chapter%20Notes/Fall%202011/chapter_19%20Fall%202011.htm.Jones AW, Jonsson KA, Neri A. pennant blood-ethanol concentration and the time of its occurrence after rapid drinking on an empty stomach. J Forensic Sci. 199136(2)376-85.Z imatkin SM, Deitrich RA. Ethanol metabolism in the brain. dependance Biology 1997. p. 387-400.Zakhari S. Alcohol metabolism and epigenetics changes. Alcohol Res. 201335(1)6-16.(IPCS) IPoCS. Methanol. Environmental Health Criteria 196. geneva WHO 1997.Strmann K, Ryan MT. Alcohol-Related EmergenciesA New Look At An Old ProblemEmergency Medicine Practice. 20013(9)9.Jacobsen D, McMartin KE. Antidotes for methanol and ethylene glycol poisoning. J Toxicol Clin Toxicol. 199735(2)127-43.Swartz RD, Millman RP, Billi JE, Bondar NP, Migdal SD, Simonian SK, et al. Epidemic methanol poisoning clinical and biochemical analysis of a recent episode. Medicine (Baltimore). 198160(5)373-82.Tephly TR. The toxicity of methanol. manner Sci. 199148(11)1031-41.Martin-Amat G, McMartin KE, Hayreh SS, Hayreh MS, Tephly TR. Methanol poisoning ocular toxicity produced by formate. Toxicol Appl Pharmacol. 197845(1)201-8.Nicholls P. The effect of formate on cytochrome aa3 and on electron transport in the intact respiratory chain. Biochim Biophys Acta. 1976430(1)13-29.Alonso JR, Cardellach F, Lopez S, Casademont J, miro O. Carbon monoxide specifically inhibits cytochrome c oxidase of human mitochondrial respiratory chain. Pharmacol Toxicol. 200393(3)142-6.Fontanesi F, Soto IC, Barrientos A. Cytochrome c oxidase biosynthesis new levels of regulation. IUBMB Life. 200860(9)557-68.Shah S, Pandey V, Thakore N, Mehta I. Study of 63 cases of methyl alcohol poisoning (hooch tragedy in Ahmedabad). J Assoc Physicians India. 20126034-6.Jammalamadaka D, Raissi S. Ethylene glycol, methanol and isopropyl alcohol intoxication. Am J Med Sci. 2010339(3)276-81.Sejersted OM, Jacobsen D, Ovrebo S, Jansen H. Formate concentrations in plasma from patients poisoned with methanol. Acta Med Scand. 1983213(2)105-10.Jacobsen D, McMartin KE. Methanol and ethylene glycol poisonings. mechanics of toxicity, clinical course, diagnosis and treatment. Med Toxicol. 19861(5)309-34.Bestic M, Blackford M, Reed M. Fomepizole a critical assessment of current dosing recommendations. J Clin Pharmacol. 200949(2)130-7.Hall TL. Fomepizole in the treatment of ethylene glycol poisoning. Cjem. 20024(3)199-204.Rathi M, Sakhuja V, Jha V. visual blurring and metabolic acidosis after ingestion of bootlegged alcohol. Hemodial Int. 200610(1)8-14.Suki WN, Massry SG. Therapy of renal diseases and related disorders Springer 1991.Kapur G, Valentini RP, imam AA, Jain A, Mattoo TK. Serum osmolal gap in patients with idiopathic nephrotic syndrome and severe edema. Pediatrics. 2007119(6)e1404-7.NICE. When to suspect child maltreatment. July 2009.

Health Benefits and Problems of Drinking Green Tea

health Benefits and Problems of Drinking putting cat valium subsequentlynoon aft(prenominal)noon afternoon afternoon afternoon afternoon afternoon afternoon afternoon afternoon afternoon afternoon afternoon afternoon afternoon tea leaf leaf leaf leaftimetimetimetime page number leaftime era sequence leaftime leaftimetime leaf leaftimetime Introduction fountain laternoon afternoon teatime leaf leaf was originated from china and has been consumed for thousands of years. It was initi exclusivelyy expendd as a congenital remedy and in religious ceremonies in the freshman place it became a pot suitable. Heavy chiliad tea alcohol addictioners like the monks and japanese collapse been k at a time to live long-term than aver maturate pack. It is fill that first-string spending of tea is good beca substance abuse it serve ups to let loose one and b bely(a)s mind, decrease his need for sleep, and lightens his weight by step-do wn fat in the proboscis system. These observations exhaust been gradu eachy proven by scientists. Today, several(prenominal) one thousand thousand cups of special K tea ar consumed casual by bulk round the orb. It has become one of the roughly goodly consumed soak ups and car parkplace even among young generations who ar headness conscious. Although the studyity of juice reamers argon Asians, it is gaining generality in the West as to a greater extent than(prenominal) pack hear how upright it bottom be to serviceman health. legion(predicate) an(prenominal) people who use to whoop it up coffee or disconsolate tea with milk atomic number 18 at give joining the trend of boozing spurt tea. Those who do not pull in sex intoxication kilobyteish tea precisely want its health benefits depose take chiliad tea excerpts in the stage of supplements.Aims for the dissertationA lot of studies and reticuloendothelial systemearch adjudge been done on light- kibibyteness tea extracts and their effectuate on health the past few decades. While n aboriginal scientists confirmed the goodness of chiliad tea, some experts expressed concerns nigh the authorization health risks of consuming excessively much verdancy tea extracts. The objective of this paper is to look at the benefits and drawbacks of consuming commonness tea. It in any case attempts to get hold out whether jet tea is really so good and as honorable as so umteen people claim or think it to be.Methodologythither argon now many books closely verdancy tea, websites designed to avouch and update visitors on parkland tea, as swell up as thousands of scientific articles, look into studies and media reports on the health benefits and authorization risks. This paper was based on information and data from secondary reference work, primarily literature review of books, daybook articles searched from the Internet database and modernisticspaper reports. Upd ates from government and formalised websites were overly apply.Overall structureThis dissertation looks at the history of colourness tea, its composition, applications and uses. It thence discusses the health benefits and potency risks of the discolor tea extracts, as well as the controversy slightly some of the health claims.Background in that respect argon diametric varieties of the tea positions and as many as ergocalciferol existing species of tea big(a) in around 50 varied countries, with china having the or so species than the some early(a)s. well-nigh tea specialists prefer to cultivate the species camelia sinensis which al just intimately all honey embrocate tea comes from. common land teas are shake up exclusively from the young leaves and buds of the camelia sinensis localize. This plant is a slow- amazeing ever color immortal tree of the genus Camellia, which survives in tropic or sub-tropical rainforest climates and thrives at altitudes of 2,1 00 meters preceding(prenominal) sea-level. The two parent strains were originated in Darjeeling, Assam and chinaware. In order to harvest them to a greater extent(prenominal)(prenominal)(prenominal) easily and conveniently, the trees are unbroken short as shrubs. There is no uniform grading for potassium tea. Good choice youngness tea consists of a leaf and a bud. The eight criteria to determine good common land tea are the appearance, shape, colour, completeness, aroma, liquor, feel and wet leaf. third estate tea affect tea leafs are classified into cardinal major(ip) guinea pigs, depending on how they are touch on young, gloomy and oolong. reverse lightning teas are made from unfermented leaves. They are locomoteed, cook, or pan-fried most immediately after beingness picked. Since thither is no time for them to ferment, no chemical qualifying devolvered. This is wherefore it tends to be lighter in dissimulation and get to the excellent unfledged char acter. Oolong teas are produced when the fresh leaves are subjected to a partial agitation stage onward dry out outing. barren teas bear up under post-harvest ferment stage forrader drying and steaming. As a end of the fermentation and oxidisation, many of the theatrical components in the tea leaves that are beneficial for health are destroyed during the takings of inexorable tea. parkland tea is considered separate than disgraceful tea or oolong tea for health reasons because it does not go done fermentation or oxidation during its exertion. It is the purest form of all teas.In China, leafy vegetable tea leaves are allowed to dry naturally before they are roasted or pan-fried. Such crossments save fermentation and soften the leaves which bequeath then be rol direct and twist to remove additional moisture. The Japanese use a steaming method before rolling, twisting and drying the leaves. Chinas green tea is cognise to be the most(prenominal) delicate of all with a good-natured and mild grassy essay. whatever of the top hat Chinese green tea like fine Dragonwell could result in five or more selections. The best green teas are those picked during early origin around the time of the Qing Ming Festival. Modern tea know could list 500 or more green teas which could be force and elegant slightly contrastively to throw slightly varied taste. annals of green teaGreen tea has been used by people as a healthy and healthful drink for thousands of years. There are many different stories more or slight how it was first observe. The most popular one from China dated as out-of-the- focus(prenominal) back as 2737 B.C. The Chinese legend described how Shen Nong accidentally discovered the soothing taste of the drinking after a leaf dropped from a tea plant into a pot of boiling water musical composition he was in the garden. He became very interested in the selection and began to study active its unhomogeneous healing properties. O ther stories of tea contact lens it with battery-acid Buddhism. Whichever is true, there is no doubt that tea was originated from China. Anthropologists have reasons to believe that prehistoric pityings animation in the area of Yunnan chewed on the leaves of tea trees to increase their alertness when hunting. odoriferous green tea leaves were gradually used by people for medicinal properties such(prenominal) as to treat depression, digestive and loathsome conditions. During the Han dynasty, tea plants were known to be conjuren by monasteries in Sichuan. Some people started to steam tea leaves and then compressed them into cakes. These tea bricks would be baked and primed(p) so that they could be prevented from spoiling and be kept for a seven-day time. By the Tang Dynasty, as tea cultivation improved and distri thate increase, tea potable became very popular in the upper class. tea rules and ceremony were developed during this golden age of tea. Gradually, tea was consum ed as a common healthy drink for all levels of society in China and Tibet instead of in the chief(prenominal) used as a remedy to treat different health complaints for certain groups of people. some A.D. 780, a book sacred to tea cal direct Cha Ching (Tea Classics) written by Lu Yu was create. He described in great details how tea was grown, well-mannered and processed. He even wrote about the utensils and proper way of tea consumption. It was Lu Yu who transformed the process of tea drinking into a form of art, which would in conclusion be passed to Japan by monks who travelled around Asia. As the popularity of drinking tea continued to grow in China, a tea socialization began to develop in Zen ceremonies and secular society in Japan, where the tea plant was able to aline very well. The tradition of drinking green tea involves a wide range of green tea and is shut away an weighty part of their society.By the 12th century, tea plants were already exported to Japan on a b road scale. It was until the 14th century when the culture of drinking tea was first introduced to europium via the Silk Road and soon spread to different parts of the world. During the 1600s a Chinese ambassador brought tea to Moscow which led to a flourishing tea trade to Russia. The Manchus were in power when China was the most important commerce country in the world and tea trade was a monopoly. The Lusitanian were the first traders to bring tea to atomic number 63 in large scale. China was able to be a fillet of sole exporter of tea by safekeeping the knowledge of tea cultivation proficiency for a long time. It was the British, impatient(predicate) to learn how to cultivate tea, who uncovered the nous-teaser of growing tea international China in the 1800s. They sent a man to China who masked himself as a merchant. The seeds he dispassionate in China were brought to India merely efforts to cultivate them failed. However, experiments use the Chinese techniques to grow local India tea plant were successful. Since the 19th century, the British began to cultivate tea on plantations in the colonies of India and Sri Lanka. It was that then when black tea, mass-produced and interchange in packets, became more popular in the rest of the world.Nowadays, the tea plant is cultivate in many countries around the world, with China, Japan, India and Sri Lanka being the greatest producers. somewhat 3.1 million tons of dried tea is produced every year, 20% of which is green tea.Although green tea has been consumed by the Chinese and Japanese for such a long time, its popularity increased only gradually in the West as the health benefits became more astray known. This is because green tea research has been astray conducted only in late(a) years by scientists. In detail, well-publicized results of research on green tea have been available only since the early 1990s. Green tea is now one of the most popular beverage consumed by people too water. In some p laces, brewed tea steeped from cautiously harvested green tea leaves of alright grown tea tree is tough like prized booze or rare coffee. As studies continue to attest evidence of its benefits, green tea go out continue to be want after by more and more people everywhere. The use of green tea and its extracts by manufacturers will continue to increase as green teas reputation keeps growing.Green tea componentsWhile the history of green tea is long and interesting, its chemistry is analyzable and studied by scientists only sort of recently. To understand more about green tea extracts and their effectuate on health, it is necessary to look at the composition as well as chemical and biochemical properties of green tea.The composition of green tea leaf is very similar to that of different fresh leaf since green tea, being the most natural form of tea, is made from unfermented leaves from the tea plant. sole(prenominal) a few changes to the enzymes of the leaves occur right af ter they are tweak from the plant and some untested volatile substances are produced when they are dried.The buds and leaves of the tea plant contain carbohyd esteems, proteins, lipids, enzymes and the patrimonial material necessary for growth and photosynthesis. The briny constituents of the leaves are polyphenols, the catechin and catechin-derived antioxidants caffeine theobromine theophylline and theanine. Other rises in green tea that have-to doe with the kind health are fluoride, minerals, vitamins such as B1, B2 and C, and soak up elements such as atomic number 24 and manganese.Table 1 Mean slice (%) of Green Tea step upGreen tea*Phenolic compounds**30Fibre26Proteins15Others carbohydrates7Lipids7Minerals5 aminic acids4Pigments2 oxidise phenolic compounds***0*Data referred to dry weight of tea leaves.**especially flavonoids.***Especially thearubigins and theaflavins.Sources Belitz DH, Grosch W(1997), Qu?mica de los Alimentos. Zaragoza AcribiaThe tote up of these ingr edients differs concord to where the green tea is cultivated and age of the leaves. Young leaves and buds contain more caffeine opus cured leaves have larger add together of tannic acid (flavonols).2 Fresh green tea buds and leaves contain 75-80% water musical composition the polyphenol components make up the remaining 20-25% of unshakable matter. Careful drying could prevent changes to the fighting(a) ingredients of the green tea leaves whereas fermentation and oxidation that occur when black tea is processed would cause chemical changes. This troikas to the major difference in the cause and taste between black tea and green tea.Green tea extracts are herbal derivatives from green tea leaves which are used or taken orally by people. The extracts target be divided into 4 categories a) punishing infusions Green tea leaves are processed by soaking in alcohol solution b) velvet extracts the solution made by muscular infusion is arduous to 20 25% c) Dry extracts the s olution from concentrated infusion is further concentrated to 40 50% solids and turned into dehydrated extract powder d) partially purified extracts techniques such as solvent extraction, towboat chromatography, membrane extraction and withdrawal are used to acquire more purified derivatives of green tea in order to produce supplements like green tea tablets and capsules.Tea PolyphenolsThe color of green tea is partly over callable to chlorophyll and partly due to a kind of naturally occurring compound in it, called polyphenols. These compounds are amenable for the pungency and unique flavor of green tea. They are antioxidants which is a sign of phytochemical compounds ground in most plants, vegetables and fruits as well as coffee, cocoa, wine and tea. Polyphenols are the most biologically active group among the tea components, with antioxidative, antimutagenic and anticarcinogenic effects. icon to oxygen during enzymatic process cringes polyphenols levels. Green tea has unaltered polyphenols because foreign oolong or black tea, they do not undergo oxidation. Because of this, green tea has the greatest effect on health among all teas. In green tea, polyphenols are in the form of flavonoids. The main flavonoids present in green tea are the green tea catechins (GTC) which comprise four major derivatives (-)-epigallocatechin-3-gallate (EGCG) (represents approximately 59% of the total of catechins) (-)-epigallocatechin (EGC) (19% approximately) (-)-epicatechin-3-gallate (ECG) (13.6% approximately) and (-)-epicatechin (EC) (6.4% approximately). Catachins have a carbon structure C6-C3-C6 composed of two remindful rings.Source V. Jane, et al. (Jan 2003), Tea Catechins and Polyphenols Health effectuate, Metabolism, and Antioxidant Functions, Critical Reviews in sustenance scientific discipline and Nutrition, 43(1)89-143The catechin content of green tea depends on how the leaves are processed, the geographical location and growing conditions (e.g. soil , climate, agriculture, practices and fertilizers), the type of green tea and the infusion (e.g. brew time, temperature) Green tea polyphenols are important for their ability to rub the damaging effects of oxidation which is a process of molecular deoxyribonucleic acid damage caused by the formation of toxic molecules called unembellished sources that develop in the human body. Individual catechins have different antioxidative and health properties.Other compounds order in different plants as well as have antioxidative action. Catechins strand only in green tea however have been proved to be more potent than many well-known antioxidants. professor Catherine Rice-Evans of the Guys Hospital in capital of the United Kingdom carried out tests and determined that green tea catechins have greater effects as antioxidants than the same quantity of Vitamin C and E, or beta-carotene. She in addition graded the catechins according to the proportion of their presence in green tea. Ac cording to her study, EGCG was the most active of the catechins, responsible for 32% of the antioxidant dimension of green tea. The order from most antioxidative to least antioxidative are 1) EGCG 2) EGC 3) ECG and 4) EC.caffeine caffein is a central nervous system stimulant belong to the family of chemicals called methylxanthines. It loafer be tack together in more than sixty different plants. 8 Most of them have been utilized as foods or beverages by people since ancient measure. Caffeine is a trimethyl derivative of purine 2,6-diol. It was first discovered in coffee by Runge in 1820 and later isolated from tea by Nakabayashi. Caffeine content is normally 2.5-4.5% in dry green tea leaves. The measuring stick of caffeine in green tea drink is about 1/10 to 1/5 of that in brewed coffee.Source V. Jane, et al. (Jan 2003), Tea Catechins and Polyphenols Health effect, Metabolism, and Antioxidant Functions, Critical Reviews in Food Science and Nutrition, 43(1)89-143Caffeine has a hygienic effect on the headland and muscles which is why drinker will finger a psychological advance shortly after drinking tea. The amount of caffeine varies among different types of tea. Black tea has the greatest amount whereas green tea contains only deuce-ace the caffeine of black tea. It has been tapern in many studies that caffeine improves cognitive exploit and certain aspect of computer storage. Besides mental health, caffeine may also helps to enhance ones emotional health, for example, making the drinker feel energized and motivated to work. Caffeine is known to be a cardiac stimulant and a diuretic. It also stimulates the cerebral cortex, causing excitation in the central nervous system. However, it may have unbecoming effects on some people and its divine guidance could cause health risks instead of benefits. Because of that, this component is often removed and excluded when green tea is extracted for applications such as health supplements.NutrientsBesides polyphenols and caffeine, the two most commonly known components, green tea also actually contains many nutrients, including different kinds of vitamins and inorganic compounds.VitaminsCommercial green tea leaves contain about 280mg of Vitamin C (VC, ascorbic acid) per 100g of dried leaves. The content of Vitamin C in green tea notify be ten times that in black tea because the vitamin is partly destroyed during fermentation, which green tea does not undergo. Other vitamins constitute in green tea in different amounts are Vitamin B2, Vitamin D, Vitamin K, and carotenoids.inorganic elementsThere are many minerals in green tea such as calcium, iron, copper, sodium, zinc and potassium. Green tea skunk also be a rich source of selenium if it is grown in a soil rich in this infixed mineral. Another important mineral comprise in green tea is manganese which is used by the body in digesting protein as well as maintaining healthy mug up and connective tissue. Green tea also contains a lot of fluoride the mineral known for fighting dental cavities.The amounts of aluminum in green tea leaves are higher than any other plants. Fortunately, the tea plant is able to biochemically neutralize the toxicity of aluminum, which exists primarily in a make form, which is little absorbable than the ionic form, with less potential to cause adverse effect on health. Experiments on animals and people also confirm that tea catechins hind end prevent the damage caused by accumulation of aluminum in the bones.Some specific inorganic compounds in the tea plant are aluminum, fluorine, and manganese.Table 2 Inorganic Elements and their table of contents in green tea leaves (per 100g dried leaves)ElementContentElementContentN3.5 7.1(g)Al420 3,500(ppm)P0.2 0.7(g)As0.20 0.42(ppm)K1.6 2.5(g)Ba1.3 5.1(ppm)Ca0.12 0.57(g)Br7.8 25.0(ppm)Mg0.12 0.30(g)F17 260(ppm)S0.24 0.48(g)Na20 33(ppm)Fe100 200(ppm)Ni1.3 5.9(ppm)Mn500 3,000(ppm)Pb2.2 6.3(ppm)Cu15 20(ppm)Rb8 44(ppm)Mo0. 4 0.7(ppm)Sc0.2(ppm)B20 30(ppm)Se1.0 1.8(ppm)Source criterion Tables of Food Composition in Japan, Resources Council, Science and Technology Agency, Tokyo, 1991Other Components amino group group AcidsThe content of total nitrogen in green tea extracts ranges from 4.5 to 6%. Half of that are escaped amino acids, which are the building blocks of protein. The amount of amino acids in tea leaves harvested during bounciness time is larger than that during other seasons. Green tea contains some common amino acids like aspartic acid, glutamic acid, glycine, tyrosine etc. as well as an amino acid that is unique to it theanine.Green tea has four basic tastes sweet, sour, savory and bitter. There is in fact a fifth taste known as unami which is contributed by the amino acid l-theanine. This constituent was only place in 1949, by a Japanese who discovered that theanine makes up about 50% of the emancipate amino acids present in tea. Young tea buds harvested in early spring contain a lot more theanine than tea leaves harvested later in the year because the theanine are converted into catechins as the leaves mature. Green tea experts rate the unami taste most highly and consider it to be the most important factor in determining the quality of the tea. High grade green tea is more soothing to drink than lower grade ones because the l-theanine can decaffeinates tea naturally, making it taste less bitter. Scientific studies using electroencephalography show that if 8 times more theanine is present than caffeine, the effect of caffeine will be blunted. Studies have also shown that theanine increases production of dopamine in the brain, give the drinker the sense of alertness while feeling relaxed. remindful OilsAromatic oils play a major role in determining the corsage of green tea. The oils accumulate as the tea leaf grows and evaporate during and after harvest of the leaf. For green tea, some aromatic oils remain in the nett tea product, contributing to the t aste of the tea. virtually 500 different aromatic oils have been identified in tea leaves.CarbohydratesTotal carbohydrates in green tea leaves are about 40%, one third of which is cellulosic fiber. stiffen is also contained in green tea. Tea leaves harvested in the morning when there is less starch are considered to be better in quality.LipidsGreen tea leaves has an average of 4% oil by weight. The seeds of tea also contain oil of around 20-40% by weight. The oil is nondrying and has a circle temperature of -5 to + 15?C./pHealth BenefitsSince the 1990s, scientists in different countries, particularly Japan, have almost suggested that every system of the body can be benefited by green tea consumption. The polyphenols are known to overthrow the risk of cancer before genetic mutations occur by neutralizing idle stem turns, prevent cardiovascular illness by preventing LDL cholesterol from changes that elevate pith disorder, and protect the body from unhomogeneous other illnes ses. As more people around the world hear about these benefits, it has become increasingly popular for those who want a healthy life style to drink green tea as beverage or take green tea extracts as supplements.Antioxidant EffectsFree radicals are highly activated molecules that could damage the body and lead to many diseases if left alone. They take an electron form another molecule, twist it into another electron-deficient free radical that can take an electron from a third molecule and so on, star to a chain reaction. The human body has a number of antioxidant molecules that help to defend it against degenerative diseases, but sometimes they may be overwhelmed by the free radicals. Antioxidants are substances that police the body and quench free radical reactions. 8 The antioxidant property of green tea extract is the most basic of all the health benefits of green tea.Many plant foods stand an abundant source of antioxidant nutrients. Polyphenols in green tea are among the most useful. Gramza Anna et al. examined the antioxidative activity of several biologically active components from plants to sire which are safe for people and presentation high antioxidant activities if added to food with lipids such as lard. Results show that the 1000ppm green tea ethanol extract subdue the oxidation process most potently among samples of green and black tea leaves. It was observed that the antioxidant activity was higher in tea extracts containing high levels of ECG, EC and C.The US Department of Agriculture (USDA) analysed more or less 400 foods for their EGCG content and produce a report in 2007. It showed that regular green tea contains the highest denseness of antioxidants, followed by decaffeinated green tea, flavored green tea and instant or bottled green tea. That USDA study also showed why green tea is the best way to ingest antioxidants. One gram of green tea steeped in 100 millimeters of water yields 127 milligrams of catechins whereas 100 gram s of grimy chocolate contains only 54 milligrams, blueberries 52 milligrams and black grapes just 22 milligrams.Since tea contains higher levels of antioxidants than many fruits and vegetables, green tea consumption can protect the cells in the human body from damage caused by free radicals. Flavonoids, act as antioxidants, through and through four possible mechanisms 1) as reducing agents, disarming free radicals. 2) by donating enthalpy molecules to prevent the formation of free radicals. 3) by quenching vest oxygen that would other than act as a free radical in the body. 4) by binding with metals that could otherwise initiate the creation of free radicals.Among the four polyphenols in green tea, EGCG has been found to be particularly powerful as an antioxidant. Researchers from Rutgers University concluded that the strong antioxidant activities of green tea are mainly due to the higher content of EGCG after comparing the antioxidant effect of various polyphenols in green tea and oolong tea. 23 Studies of the effects of tea consumption in people confirm evident that green tea is the most effective scavenger of free radicals among the different types of tea. In one study, five adults separately drank two cups of green tea while five others drank the same amount of black tea. Both green and black teas improve the antioxidant capability of the blood, but green tea was found to be six times more powerful. Scientists also found that fresh green tea extracts is a better scavenger of singlet oxygen than puddle green tea extract. Green tea polyphenols are also effective in quenching other free radicals such as hydrogen peroxide and superoxide.Diabetes MellitusDiabetes mellitus is known to affect the structure and function of myocardium, causing increased collagen in the heart and reducing cardiac function. Babu and his team from India found that the antioxidant enzymes of diabetic rats are not sufficient and efficient enough to reduce the oxidative stress caus ed by hyperglycemia. In 2006, their investigation showed that green tea preaching is effective in controlling the antioxidant system in the heart and aorta by alleviating lipid peroxidation. In 2007, their studies suggested that administration of green tea extract may improve myocardial collagen changes in diabetic rats. They believe that the antioxidant, antihyperglycemic, and hypolipidemic effects of green tea catechins may be responsible and concluded green tea may nominate a therapeutic option for the treatment of cardiovascular complications in diabetes.human immunodeficiency virusThe majority of the worlds 33 million human immunodeficiency virus cases were infected through heterosexual sex with 96% of new infections occurring in developing countries. Therefore shipway to fight the spread of human immunodeficiency virus in poor countries are passing necessary. Previously, scientists have carried out lab tests and inform that EGCG may prevent HIV from binding to the T-cells in the immune systems defend them from HIVs damage. Although they knew that EGCG inhibited HIV in test tubes, they did not know if the findings would be useful beyond the lab. 26 dear recently, researchers in Germany have found a practical way to use EGCG to help prevent the spreading of assist. The researchers found that EGCG was capable of neutralizing a protein in sperm that served as a sender for the transmission of the virus that causes AIDS during sex. They say that the use of green tea in vaginal creams could provide a simple and affordable way to reduce cases of HIV infection.Neuroprotective EffectsParkinsons unsoundnessParkinsons disease is a progressive, degenerative disorder of the central nervous system resulting from loss of dopamine-producing brain cells. A research team led by Professor Zhao affiliated to the Chinese Academy of Sciences Institute of Biophysics using an animal model of Parkinsons disease discovered that green tea polyphenols can protect dopamine neurons. He hopes that green tea polyphenols may eventually be developed into a safe drug for Parkinsons disease in humans.Alzheimers DiseaseIn an article published by the Journal of Neuroscience, researchers from University of randomness Florida reported that EGCG prevented Alzheimers-like damage in the brain of mice genetically programmed to develop the neurodegenerative disease process. They work by decreasing production of the Alzheimers-related protein called beta-amyloid which causes impertinence damage and memory loss when accumulated abnormally in the brain. The researchers think that a new generation of dietary supplements containing pure EGCG capacity be beneficial for treating Altheimers disease.Huntingtons DiseaseLike Alzheimers and Parkinsons, Huntingtons disease is also a type of neurodegenerative disease caused by protein misfolding characterized by jerky and uncontrolled movements. mutant proteins are accumulated in the brain of sufferers and become toxic to the nerve cells in the brain. A resHealth Benefits and Problems of Drinking Green TeaHealth Benefits and Problems of Drinking Green Tea IntroductionGreen tea was originated from China and has been consumed for thousands of years. It was initially used as a natural remedy and in religious ceremonies before it became a beverage. Heavy green tea drinkers like the monks and Japanese have been known to live longer than average people. It is believe that regular consumption of tea is good because it helps to relax ones mind, decrease his need for sleep, and lightens his weight by reducing fat in the body system. These observations have been gradually proven by scientists. Today, several billion cups of green tea are consumed daily by people around the world. It has become one of the most widely consumed drinks and popular even among younger generations who are health conscious. Although the majority of drinkers are Asians, it is gaining popularity in the West as more people hear how benefici al it can be to human health. Many people who used to drink coffee or black tea with milk are now joining the trend of drinking green tea. Those who do not enjoy drinking green tea but want its health benefits can take green tea extracts in the form of supplements.Aims for the dissertationA lot of studies and research have been done on green tea extracts and their effects on health the past few decades. While most scientists confirmed the goodness of green tea, some experts expressed concerns about the potential health risks of consuming too much green tea extracts. The objective of this paper is to look at the benefits and drawbacks of consuming green tea. It also attempts to find out whether green tea is really so good and as safe as so many people claim or think it to be.MethodologyThere are now many books about green tea, websites designed to inform and update visitors on green tea, as well as thousands of scientific articles, research studies and media reports on the health ben efits and potential risks. This paper was based on information and data from secondary source, mainly literature review of books, journal articles searched from the Internet database and newspaper reports. Updates from government and official websites were also used.Overall structureThis dissertation looks at the history of green tea, its composition, applications and uses. It then discusses the health benefits and potential risks of the green tea extracts, as well as the controversy about some of the health claims.BackgroundThere are different varieties of the tea plants and as many as 500 existing species of tea grown in around 50 different countries, with China having the most species than the others. Most tea specialists prefer to cultivate the species Camellia sinensis which almost all green tea comes from. Green teas are made exclusively from the young leaves and buds of the Camellia sinensis plant. This plant is a slow-growing evergreen perennial tree of the genus Camellia, w hich survives in tropical or sub-tropical rainforest climates and thrives at altitudes of 2,100 meters above sea-level. The two parent strains were originated in Darjeeling, Assam and China. In order to harvest them more easily and conveniently, the trees are kept short as shrubs. There is no uniform grading for green tea. Good quality green tea consists of a leaf and a bud. The eight criteria to determine good green tea are the appearance, shape, colour, completeness, aroma, liquor, flavour and wet leaf. Green tea processingTeas are classified into three major types, depending on how they are processed green, black and oolong. Green teas are made from unfermented leaves. They are steamed, roasted, or pan-fried almost immediately after being picked. Since there is no time for them to ferment, no chemical change occurred. This is why it tends to be lighter in color and have the delicate green character. Oolong teas are produced when the fresh leaves are subjected to a partial ferment ation stage before drying. Black teas undergo post-harvest fermentation stage before drying and steaming. As a result of the fermentation and oxidation, many of the components in the tea leaves that are beneficial for health are destroyed during the production of black tea. Green tea is considered better than black tea or oolong tea for health reasons because it does not go through fermentation or oxidation during its production. It is the purest form of all teas.In China, green tea leaves are allowed to dry naturally before they are roasted or pan-fried. Such treatments prevent fermentation and soften the leaves which will then be rolled and twisted to remove additional moisture. The Japanese use a steaming method before rolling, twisting and drying the leaves. Chinas green tea is known to be the most delicate of all with a sweet and mild grassy taste. Some of the best Chinese green tea like fine Dragonwell could result in five or more infusions. The best green teas are those picke d during early spring around the time of the Qing Ming Festival. Modern tea masters could list 500 or more green teas which could be plucked and processed slightly differently to give slightly different taste.History of green teaGreen tea has been used by people as a healthy and medicinal drink for thousands of years. There are many different stories about how it was first discovered. The most popular one from China dated as far back as 2737 B.C. The Chinese legend described how Shen Nong accidentally discovered the soothing taste of the beverage after a leaf dropped from a tea plant into a pot of boiling water while he was in the garden. He became very interested in the infusion and began to study about its various healing properties. Other stories of tea link it with Zen Buddhism. Whichever is true, there is no doubt that tea was originated from China. Anthropologists have reasons to believe that prehistoric humans living in the area of Yunnan chewed on the leaves of tea trees to increase their alertness when hunting. Fresh green tea leaves were gradually used by people for medicinal properties such as to treat depression, digestive and nervous conditions. During the Han dynasty, tea plants were known to be grown by monasteries in Sichuan. Some people started to steam tea leaves and then compressed them into cakes. These tea bricks would be baked and hardened so that they could be prevented from spoiling and be kept for a longer time. By the Tang Dynasty, as tea cultivation improved and trade increased, tea drinking became very popular in the upper class. Tea rules and ceremony were developed during this golden age of tea. Gradually, tea was consumed as a common healthy drink for all levels of society in China and Tibet instead of mainly used as a remedy to treat different health complaints for certain groups of people.Around A.D. 780, a book dedicated to tea called Cha Ching (Tea Classics) written by Lu Yu was published. He described in great details how te a was grown, cultivated and processed. He even wrote about the utensils and proper way of tea consumption. It was Lu Yu who transformed the process of tea drinking into a form of art, which would eventually be passed to Japan by monks who travelled around Asia. As the popularity of drinking tea continued to grow in China, a tea culture began to develop in Zen ceremonies and secular society in Japan, where the tea plant was able to adapt very well. The tradition of drinking green tea involves a wide range of green tea and is still an important part of their society.By the 12th century, tea plants were already exported to Japan on a large scale. It was until the 14th century when the culture of drinking tea was first introduced to Europe via the Silk Road and soon spread to other parts of the world. During the 1600s a Chinese ambassador brought tea to Moscow which led to a flourishing tea trade to Russia. The Manchus were in power when China was the most important trading country in t he world and tea trade was a monopoly. The Portuguese were the first traders to bring tea to Europe in large scale. China was able to be a sole exporter of tea by keeping the knowledge of tea cultivation technique for a long time. It was the British, eager to learn how to cultivate tea, who uncovered the secret of growing tea outside China in the 1800s. They sent a man to China who disguised himself as a merchant. The seeds he collected in China were brought to India but efforts to cultivate them failed. However, experiments using the Chinese techniques to grow local India tea plant were successful. Since the 19th century, the British began to cultivate tea on plantations in the colonies of India and Sri Lanka. It was only then when black tea, mass-produced and sold in packets, became more popular in the rest of the world.Nowadays, the tea plant is cultivated in many countries around the world, with China, Japan, India and Sri Lanka being the greatest producers. About 3.1 million to ns of dried tea is produced every year, 20% of which is green tea.Although green tea has been consumed by the Chinese and Japanese for such a long time, its popularity increased only gradually in the West as the health benefits became more widely known. This is because green tea research has been widely conducted only in recent years by scientists. In fact, well-publicized results of research on green tea have been available only since the early 1990s. Green tea is now one of the most popular beverage consumed by people besides water. In some places, brewed tea steeped from carefully harvested green tea leaves of delicately grown tea tree is treated like prized wine or rare coffee. As studies continue to show evidence of its benefits, green tea will continue to be sought after by more and more people everywhere. The use of green tea and its extracts by manufacturers will continue to increase as green teas reputation keeps growing.Green tea componentsWhile the history of green tea is long and interesting, its chemistry is complex and studied by scientists only quite recently. To understand more about green tea extracts and their effects on health, it is necessary to look at the composition as well as chemical and biochemical properties of green tea.The composition of green tea leaf is very similar to that of other fresh leaf since green tea, being the most natural form of tea, is made from unfermented leaves from the tea plant. Only a few changes to the enzymes of the leaves occur right after they are plucked from the plant and some new volatile substances are produced when they are dried.The buds and leaves of the tea plant contain carbohydrates, proteins, lipids, enzymes and the genetic material necessary for growth and photosynthesis. The main constituents of the leaves are polyphenols, the catechin and catechin-derived antioxidants caffeine theobromine theophylline and theanine. Other compounds in green tea that affect the human health are fluoride, mineral s, vitamins such as B1, B2 and C, and trace elements such as chromium and manganese.Table 1 Mean Composition (%) of Green TeaCompoundGreen tea*Phenolic compounds**30Fibre26Proteins15Others carbohydrates7Lipids7Minerals5Amino acids4Pigments2Oxidised phenolic compounds***0*Data referred to dry weight of tea leaves.**Especially flavonoids.***Especially thearubigins and theaflavins.Sources Belitz DH, Grosch W(1997), Qu?mica de los Alimentos. Zaragoza AcribiaThe amount of these ingredients differs according to where the green tea is cultivated and age of the leaves. Young leaves and buds contain more caffeine while older leaves have larger amount of tannin (flavonols).2 Fresh green tea buds and leaves contain 75-80% water while the polyphenol components make up the remaining 20-25% of solid matter. Careful drying could prevent changes to the active ingredients of the green tea leaves whereas fermentation and oxidation that occur when black tea is processed would cause chemical changes. This leads to the major difference in the effects and taste between black tea and green tea.Green tea extracts are herbal derivatives from green tea leaves which are used or taken orally by people. The extracts can be divided into 4 categories a) Strong infusions Green tea leaves are processed by soaking in alcohol solution b) Soft extracts the solution made by strong infusion is concentrated to 20 25% c) Dry extracts the solution from strong infusion is further concentrated to 40 50% solids and turned into dehydrated extract powder d) Partly purified extracts techniques such as solvent extraction, column chromatography, membrane extraction and separation are used to acquire more purified derivatives of green tea in order to produce supplements like green tea tablets and capsules.Tea PolyphenolsThe color of green tea is partly due to chlorophyll and partly due to a kind of naturally occurring compound in it, called polyphenols. These compounds are responsible for the pungency and unique flavor of green tea. They are antioxidants which is a type of phytochemical compounds found in most plants, vegetables and fruits as well as coffee, cocoa, wine and tea. Polyphenols are the most biologically active group among the tea components, with antioxidative, antimutagenic and anticarcinogenic effects. Exposure to oxygen during enzymatic process reduces polyphenols levels. Green tea has unaltered polyphenols because unlike oolong or black tea, they do not undergo oxidation. Because of this, green tea has the greatest effect on health among all teas. In green tea, polyphenols are in the form of flavonoids. The main flavonoids present in green tea are the green tea catechins (GTC) which comprise four major derivatives (-)-epigallocatechin-3-gallate (EGCG) (represents approximately 59% of the total of catechins) (-)-epigallocatechin (EGC) (19% approximately) (-)-epicatechin-3-gallate (ECG) (13.6% approximately) and (-)-epicatechin (EC) (6.4% approximately). Catachins have a carbon structure C6-C3-C6 composed of two aromatic rings.Source V. Jane, et al. (Jan 2003), Tea Catechins and Polyphenols Health Effects, Metabolism, and Antioxidant Functions, Critical Reviews in Food Science and Nutrition, 43(1)89-143The catechin content of green tea depends on how the leaves are processed, the geographical location and growing conditions (e.g. soil, climate, agriculture, practices and fertilizers), the type of green tea and the infusion (e.g. brew time, temperature) Green tea polyphenols are important for their ability to halt the damaging effects of oxidation which is a process of molecular DNA damage caused by the formation of toxic molecules called free radicals that develop in the human body. Individual catechins have different antioxidative and health properties.Other compounds found in different plants also have antioxidative action. Catechins found only in green tea however have been proved to be more effective than many well-known antioxidants. Pro fessor Catherine Rice-Evans of the Guys Hospital in London carried out tests and determined that green tea catechins have greater effects as antioxidants than the same quantity of Vitamin C and E, or beta-carotene. She also ranked the catechins according to the proportion of their presence in green tea. According to her study, EGCG was the most active of the catechins, responsible for 32% of the antioxidant property of green tea. The order from most antioxidative to least antioxidative are 1) EGCG 2) EGC 3) ECG and 4) EC.CaffeineCaffeine is a central nervous system stimulant belonging to the family of chemicals called methylxanthines. It can be found in more than sixty different plants. 8 Most of them have been utilized as foods or beverages by people since ancient times. Caffeine is a trimethyl derivative of purine 2,6-diol. It was first discovered in coffee by Runge in 1820 and later isolated from tea by Nakabayashi. Caffeine content is usually 2.5-4.5% in dry green tea leaves. Th e amount of caffeine in green tea drink is about 1/10 to 1/5 of that in brewed coffee.Source V. Jane, et al. (Jan 2003), Tea Catechins and Polyphenols Health Effects, Metabolism, and Antioxidant Functions, Critical Reviews in Food Science and Nutrition, 43(1)89-143Caffeine has a strong effect on the brain and muscles which is why drinker will experience a mental boost shortly after drinking tea. The amount of caffeine varies among different types of tea. Black tea has the greatest amount whereas green tea contains only one-third the caffeine of black tea. It has been shown in many studies that caffeine improves cognitive performance and certain aspect of memory. Besides mental health, caffeine may also helps to enhance ones emotional health, for example, making the drinker feel energized and motivated to work. Caffeine is known to be a cardiac stimulant and a diuretic. It also stimulates the cerebral cortex, causing excitation in the central nervous system. However, it may have adve rse effects on some people and its intake could cause health risks instead of benefits. Because of that, this component is often removed and excluded when green tea is extracted for applications such as health supplements.NutrientsBesides polyphenols and caffeine, the two most commonly known components, green tea also actually contains many nutrients, including different kinds of vitamins and inorganic compounds.VitaminsCommercial green tea leaves contain about 280mg of Vitamin C (VC, ascorbic acid) per 100g of dried leaves. The content of Vitamin C in green tea can be ten times that in black tea because the vitamin is partly destroyed during fermentation, which green tea does not undergo. Other vitamins found in green tea in different amounts are Vitamin B2, Vitamin D, Vitamin K, and carotenoids.Inorganic elementsThere are many minerals in green tea such as calcium, iron, copper, sodium, zinc and potassium. Green tea can also be a rich source of selenium if it is grown in a soil ri ch in this essential mineral. Another important mineral found in green tea is manganese which is used by the body in digesting protein as well as maintaining healthy bones and connective tissue. Green tea also contains a lot of fluoride the mineral known for fighting dental cavities.The amounts of aluminum in green tea leaves are higher than any other plants. Fortunately, the tea plant is able to biochemically neutralize the toxicity of aluminum, which exists mainly in a chelate form, which is less absorbable than the ionic form, with less potential to cause adverse effect on health. Experiments on animals and people also confirm that tea catechins can prevent the damage caused by accumulation of aluminum in the bones.Some specific inorganic compounds in the tea plant are aluminum, fluorine, and manganese.Table 2 Inorganic Elements and their contents in green tea leaves (per 100g dried leaves)ElementContentElementContentN3.5 7.1(g)Al420 3,500(ppm)P0.2 0.7(g)As0.20 0.42(ppm)K1.6 2.5(g)Ba1.3 5.1(ppm)Ca0.12 0.57(g)Br7.8 25.0(ppm)Mg0.12 0.30(g)F17 260(ppm)S0.24 0.48(g)Na20 33(ppm)Fe100 200(ppm)Ni1.3 5.9(ppm)Mn500 3,000(ppm)Pb2.2 6.3(ppm)Cu15 20(ppm)Rb8 44(ppm)Mo0.4 0.7(ppm)Sc0.2(ppm)B20 30(ppm)Se1.0 1.8(ppm)Source Standard Tables of Food Composition in Japan, Resources Council, Science and Technology Agency, Tokyo, 1991Other ComponentsAmino AcidsThe content of total nitrogen in green tea extracts ranges from 4.5 to 6%. Half of that are free amino acids, which are the building blocks of protein. The amount of amino acids in tea leaves harvested during spring time is larger than that during other seasons. Green tea contains some common amino acids like aspartic acid, glutamic acid, glycine, tyrosine etc. as well as an amino acid that is unique to it theanine.Green tea has four basic tastes sweet, sour, salty and bitter. There is in fact a fifth taste known as unami which is contributed by the amino acid l-theanine. This constituent was only ide ntified in 1949, by a Japanese who discovered that theanine makes up about 50% of the free amino acids present in tea. Young tea buds harvested in early spring contain a lot more theanine than tea leaves harvested later in the year because the theanine are converted into catechins as the leaves mature. Green tea experts rate the unami taste most highly and consider it to be the most important factor in determining the quality of the tea. High grade green tea is more soothing to drink than lower grade ones because the l-theanine can decaffeinates tea naturally, making it taste less bitter. Scientific studies using electroencephalography show that if 8 times more theanine is present than caffeine, the effect of caffeine will be blunted. Studies have also shown that theanine increases production of dopamine in the brain, giving the drinker the sense of alertness while feeling relaxed.Aromatic OilsAromatic oils play a major role in determining the fragrance of green tea. The oils accumu late as the tea leaf grows and evaporate during and after harvest of the leaf. For green tea, some aromatic oils remain in the final tea product, contributing to the taste of the tea. About 500 different aromatic oils have been identified in tea leaves.CarbohydratesTotal carbohydrates in green tea leaves are about 40%, one third of which is cellulosic fiber. Starch is also contained in green tea. Tea leaves harvested in the morning when there is less starch are considered to be better in quality.LipidsGreen tea leaves has an average of 4% oil by weight. The seeds of tea also contain oil of around 20-40% by weight. The oil is nondrying and has a solidifying temperature of -5 to + 15?C./pHealth BenefitsSince the 1990s, scientists in different countries, particularly Japan, have almost suggested that every system of the body can be benefited by green tea consumption. The polyphenols are known to reduce the risk of cancer before genetic mutations occur by neutralizing free radicals, pre vent cardiovascular disease by preventing LDL cholesterol from changes that promote heart disease, and protect the body from various other illnesses. As more people around the world hear about these benefits, it has become increasingly popular for those who want a healthy life style to drink green tea as beverage or take green tea extracts as supplements.Antioxidant EffectsFree radicals are highly reactive molecules that could damage the body and lead to many diseases if left alone. They take an electron form another molecule, turning it into another electron-deficient free radical that can take an electron from a third molecule and so on, leading to a chain reaction. The human body has a number of antioxidant molecules that help to defend it against degenerative diseases, but sometimes they may be overwhelmed by the free radicals. Antioxidants are substances that patrol the body and quench free radical reactions. 8 The antioxidant property of green tea extract is the most basic of all the health benefits of green tea.Many plant foods provide an abundant source of antioxidant nutrients. Polyphenols in green tea are among the most effective. Gramza Anna et al. examined the antioxidative activity of several biologically active components from plants to find which are safe for people and showing high antioxidant activities if added to food with lipids such as lard. Results show that the 1000ppm green tea ethanol extract inhibited the oxidation process most strongly among samples of green and black tea leaves. It was observed that the antioxidant activity was higher in tea extracts containing high levels of ECG, EC and C.The US Department of Agriculture (USDA) analysed nearly 400 foods for their EGCG content and published a report in 2007. It showed that regular green tea contains the highest concentration of antioxidants, followed by decaffeinated green tea, flavored green tea and instant or bottled green tea. That USDA study also showed why green tea is the best way to ingest antioxidants. One gram of green tea steeped in 100 millimeters of water yields 127 milligrams of catechins whereas 100 grams of dark chocolate contains only 54 milligrams, blueberries 52 milligrams and black grapes just 22 milligrams.Since tea contains higher levels of antioxidants than many fruits and vegetables, green tea consumption can protect the cells in the human body from damage caused by free radicals. Flavonoids, act as antioxidants, through four possible mechanisms 1) as reducing agents, disarming free radicals. 2) by donating hydrogen molecules to prevent the formation of free radicals. 3) by quenching singlet oxygen that would otherwise act as a free radical in the body. 4) by binding with metals that could otherwise initiate the creation of free radicals.Among the four polyphenols in green tea, EGCG has been found to be particularly effective as an antioxidant. Researchers from Rutgers University concluded that the strong antioxidant activities of green tea are mainly due to the higher content of EGCG after comparing the antioxidant effect of various polyphenols in green tea and oolong tea. 23 Studies of the effects of tea consumption in people confirm evident that green tea is the most effective scavenger of free radicals among the different types of tea. In one study, five adults each drank two cups of green tea while five others drank the same amount of black tea. Both green and black teas improve the antioxidant capability of the blood, but green tea was found to be six times more powerful. Scientists also found that fresh green tea extracts is a better scavenger of singlet oxygen than stale green tea extract. Green tea polyphenols are also effective in quenching other free radicals such as hydrogen peroxide and superoxide.Diabetes MellitusDiabetes mellitus is known to affect the structure and function of myocardium, causing increased collagen in the heart and reducing cardiac function. Babu and his team from India found that t he antioxidant enzymes of diabetic rats are not sufficient and efficient enough to reduce the oxidative stress caused by hyperglycemia. In 2006, their investigation showed that green tea treatment is effective in controlling the antioxidant system in the heart and aorta by alleviating lipid peroxidation. In 2007, their studies suggested that administration of green tea extract may improve myocardial collagen changes in diabetic rats. They believe that the antioxidant, antihyperglycemic, and hypolipidemic effects of green tea catechins may be responsible and concluded green tea may provide a therapeutic option for the treatment of cardiovascular complications in diabetes.HIVThe majority of the worlds 33 million HIV cases were infected through heterosexual sex with 96% of new infections occurring in developing countries. Therefore ways to fight the spread of HIV in poor countries are extremely necessary. Previously, scientists have carried out lab tests and reported that EGCG may prev ent HIV from binding to the T-cells in the immune systems protecting them from HIVs damage. Although they knew that EGCG inhibited HIV in test tubes, they did not know if the findings would be useful beyond the lab. 26 Just recently, researchers in Germany have found a practical way to use EGCG to help prevent the spreading of AIDS. The researchers found that EGCG was capable of neutralizing a protein in sperm that served as a vector for the transmission of the virus that causes AIDS during sex. They say that the use of green tea in vaginal creams could provide a simple and affordable way to reduce cases of HIV infection.Neuroprotective EffectsParkinsons DiseaseParkinsons disease is a progressive, degenerative disorder of the central nervous system resulting from loss of dopamine-producing brain cells. A research team led by Professor Zhao affiliated to the Chinese Academy of Sciences Institute of Biophysics using an animal model of Parkinsons disease discovered that green tea polyp henols can protect dopamine neurons. He hopes that green tea polyphenols may eventually be developed into a safe drug for Parkinsons disease in humans.Alzheimers DiseaseIn an article published by the Journal of Neuroscience, researchers from University of South Florida reported that EGCG prevented Alzheimers-like damage in the brain of mice genetically programmed to develop the neurodegenerative disease process. They work by decreasing production of the Alzheimers-related protein called beta-amyloid which causes nerve damage and memory loss when accumulated abnormally in the brain. The researchers think that a new generation of dietary supplements containing pure EGCG might be beneficial for treating Altheimers disease.Huntingtons DiseaseLike Alzheimers and Parkinsons, Huntingtons disease is also a type of neurodegenerative disease caused by protein misfolding characterized by jerky and uncontrolled movements. Mutant proteins are accumulated in the brain of sufferers and become toxi c to the nerve cells in the brain. 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