Health Benefits and Problems of Drinking Green Tea

Health Benefits and Problems of Drinking Green Tea Introduction Green 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 beneficial 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 w ho do not enjoy drinking green tea but want its health benefits can take green tea extracts in the form of supplements. Aims for the dissertation A 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. Methodology There 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 benefits 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 structure This 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. Background There 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, which 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 processing Teas 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 fermentation 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 picked 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 tea Green 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 b e 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 tea 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 the 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 loca l 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 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 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 components While 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, minerals, vitamins such as B1, B2 and C, and trace elements such as chromium and manganese. Table 1 Mean Composition (%) of Green Tea Compound Green tea* Phenolic compounds** 30 Fibre 26 Proteins 15 Others carbohydrates 7 Lipids 7 Minerals 5 Amino acids 4 Pigments 2 Oxidised 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: Acribia] The 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 Polyphenols The 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):89-143] The 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. Professor 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. Caffeine Caffeine 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. The 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):89-143] Caffeine 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 adverse 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. Nutrients Besides polyphenols and caffeine, the two most commonly known components, green tea also actually contains many nutrients, including different kinds of vitamins and inorganic compounds. Vitamins Commercial 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 elements There 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 rich 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) ElementContent ElementContent N3.5 7.1   Ã‚  (g)  Ã‚   Al420 3,500   Ã‚  (ppm)  Ã‚   P0.2 0.7   Ã‚  (g)  Ã‚   As0.20 0.42   Ã‚  (ppm)  Ã‚   K1.6 2.5   Ã‚  (g)  Ã‚   Ba1.3 5.1   Ã‚  (ppm)  Ã‚   Ca0.12 0.57   Ã‚  (g)  Ã‚   Br7.8 25.0   Ã‚  (ppm)  Ã‚   Mg0.12 0.30   Ã‚  (g)  Ã‚   F17 260   Ã‚  (ppm)  Ã‚   S0.24 0.48   Ã‚  (g)  Ã‚   Na20 33   Ã‚  (ppm)  Ã‚   Fe100 200   Ã‚  (ppm)  Ã‚   Ni1.3 5.9   Ã‚  (ppm)  Ã‚   Mn500 3,000   Ã‚  (ppm)  Ã‚   Pb2.2 6.3   Ã‚  (ppm)  Ã‚   Cu15 20   Ã‚  (ppm)  Ã‚   Rb8 44   Ã‚  (ppm)  Ã‚   Mo0.4 0.7   Ã‚  (ppm)  Ã‚   Sc0.2   Ã‚  (ppm)  Ã‚   B20 30   Ã‚  (ppm)  Ã‚   Se1.0 1.8   Ã‚  (ppm)  Ã‚   [Source: Standard Tables of Food Composition in Japan, Resources Council, Science and Technology Agency, Tokyo, 1991] Other Components Amino Acids The 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 identified 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 d opamine in the brain, giving the drinker the sense of alertness while feeling relaxed. Aromatic Oils Aromatic oils play a major role in determining the fragrance 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 final tea product, contributing to the taste of the tea. About 500 different aromatic oils have been identified in tea leaves. Carbohydrates Total 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. Lipids Green 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.>/p> Health Benefits Since 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, prevent 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 Effects Free 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 Mellitus Diabetes 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 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. HIV The 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 prevent 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 Effects Parkinsons Disease Parkinsons 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 Disease In 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 Disease Like 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 res Health Benefits and Problems of Drinking Green Tea Health Benefits and Problems of Drinking Green Tea Introduction Green 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 beneficial 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 w ho do not enjoy drinking green tea but want its health benefits can take green tea extracts in the form of supplements. Aims for the dissertation A 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. Methodology There 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 benefits 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 structure This 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. Background There 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, which 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 processing Teas 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 fermentation 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 picked 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 tea Green 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 b e 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 tea 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 the 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 loca l 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 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 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 components While 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, minerals, vitamins such as B1, B2 and C, and trace elements such as chromium and manganese. Table 1 Mean Composition (%) of Green Tea Compound Green tea* Phenolic compounds** 30 Fibre 26 Proteins 15 Others carbohydrates 7 Lipids 7 Minerals 5 Amino acids 4 Pigments 2 Oxidised 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: Acribia] The 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 Polyphenols The 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):89-143] The 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. Professor 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. Caffeine Caffeine 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. The 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):89-143] Caffeine 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 adverse 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. Nutrients Besides polyphenols and caffeine, the two most commonly known components, green tea also actually contains many nutrients, including different kinds of vitamins and inorganic compounds. Vitamins Commercial 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 elements There 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 rich 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) ElementContent ElementContent N3.5 7.1   Ã‚  (g)  Ã‚   Al420 3,500   Ã‚  (ppm)  Ã‚   P0.2 0.7   Ã‚  (g)  Ã‚   As0.20 0.42   Ã‚  (ppm)  Ã‚   K1.6 2.5   Ã‚  (g)  Ã‚   Ba1.3 5.1   Ã‚  (ppm)  Ã‚   Ca0.12 0.57   Ã‚  (g)  Ã‚   Br7.8 25.0   Ã‚  (ppm)  Ã‚   Mg0.12 0.30   Ã‚  (g)  Ã‚   F17 260   Ã‚  (ppm)  Ã‚   S0.24 0.48   Ã‚  (g)  Ã‚   Na20 33   Ã‚  (ppm)  Ã‚   Fe100 200   Ã‚  (ppm)  Ã‚   Ni1.3 5.9   Ã‚  (ppm)  Ã‚   Mn500 3,000   Ã‚  (ppm)  Ã‚   Pb2.2 6.3   Ã‚  (ppm)  Ã‚   Cu15 20   Ã‚  (ppm)  Ã‚   Rb8 44   Ã‚  (ppm)  Ã‚   Mo0.4 0.7   Ã‚  (ppm)  Ã‚   Sc0.2   Ã‚  (ppm)  Ã‚   B20 30   Ã‚  (ppm)  Ã‚   Se1.0 1.8   Ã‚  (ppm)  Ã‚   [Source: Standard Tables of Food Composition in Japan, Resources Council, Science and Technology Agency, Tokyo, 1991] Other Components Amino Acids The 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 identified 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 d opamine in the brain, giving the drinker the sense of alertness while feeling relaxed. Aromatic Oils Aromatic oils play a major role in determining the fragrance 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 final tea product, contributing to the taste of the tea. About 500 different aromatic oils have been identified in tea leaves. Carbohydrates Total 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. Lipids Green 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.>/p> Health Benefits Since 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, prevent 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 Effects Free 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 Mellitus Diabetes 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 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. HIV The 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 prevent 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 Effects Parkinsons Disease Parkinsons 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 Disease In 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 Disease Like 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 res

Voting Machine

(Department of electronics engineering) RIZVI COLLEGE OF ENGINEERING BANDRA (WEST), MUMBAI-400050 UNIVERSITY OF MUMBAI ACADEMIC YEAR 2012-13 FOR THE FULFILLMENT OF THE PROJECT (TE) ELECTRONIC WORKSHOP (EWS) LCD BASED VOTING MACHINE USING 8051 AND VENDING MACHINE A project report Submitted by NIKITA MUDRAS TRUPTI LIMBAD SABERA YASMIN UNDER THE GUIDANCE OF PROF. PRASAD DHURI PROF. SOHAIL SIDDIQUI RIZVI COLLEGE OF ENGINEERING, RIZVI COMPLEX, OFF CARTER ROAD BANDRA (W), MUMBAI – 400050 YEAR: 2012-13 UNIVERSITY OF MUMBAI (DEPARTMENT OF ELECTRONICS) CERTIFICATEThis is to certify that the following students NIKITA MUDRAS TRUPTI LIMBAD SABERA YASMIN Have successfully completed the synopsis work of project on LCD BASED VOTING MACHINE USING 8051 AND VENDING MACHINE ___________________ _________________ PROF. PRASAD S. DHURI EXTERNAL EXAMINER (PROJECT GUIDE) ___________________ _________________ PROF . SOHAIL SIDDIQUI PROF . NARGIS SHAIKH (PROJECT GUIDE) (HOD) PREFACEWe take an opportun ity to present the project report on â€Å"lcd based voting machine and vending machine† and put before users some useful information about our project. We have made sincere attempts and taken every care to present this matter in precise and compact form. We are sure that the information contained in this volume would certainly prove useful for better insight in the scope and dimension of the subject. The task of completing the project though being difficult but was made quite simple,intresting and successful due to deep involvement and complete dedication of our group members.ACKNOWLEDGEMENT It is indeed of great pleasure and proud privilege to be able to present the project on â€Å"Lcd Based Voting Machine Using 8051† The completion of project work is a milestone in student’s life and its execution is inevitable in the hands of guide. we highly indebt the project guide Mr. Prasad Dhuri for this invaluable guidance and appreciation for giving form and substanc e to this project. it is due to his enduring efforts, patience and enthusiasm, which has given a sense of direction and purposefulness to this project and ultimately made it a success.We would like to tender our sincere thanks to the staff members for their co-operation. We would also like to express our deep regards and gratitude to the principal Dr. Varsha Shah, our HOD Prof. Nargis Shaikh. We would also like to thank the non teaching staff and our friends who have helped us all the time in the way or the other. LIST OF CONTENT LCD BASED VOTING MACHINE USING 8051 MICROCONTROLLER 1. Introduction 08 2. Circuit diagram 09 . Components 11 4. Program for IC 15 5. Working 30 6. PCB layout 31 7. Advantages 32 8. Future Scope 33 VENDING MACHINE 1.Introduction 36 2. Flowchart 37 3. Working 38 4. VHDL code 40 5. Output Waveforms 44 6. Applications & uses 45 REFRENCES 47LCD BASED VOTING MACHINE USING 8051 MICROCONTROLLER [pic] INTRODUCTION This LCD based electronic voting machine is de signed for four candidates. The input part consists of a set of six tactile switches. The switches and 16Ãâ€"2 LCD are interfaced to microcontroller AT89C51 for various operations and displays. The provision of casting votes for the candidates has been provided through four of these switches. These switches are made active high and connected to pins 2-5 (P1^1 – P1^4) of the controller. The remaining two switches (both active low) are to start and stop the voting procedure.They are connected to pins 1 and 6 (P1^0 and P1^5) respectively. The Init (start) switch initializes the voting system when pressed, while the Stop switch ends the voting and displays the poll results on LCD screen. For more details on working with LCD, refer LCD interfacing with 8051. The data pins of the LCD (pins 7-14) are connected to the output port P2 of the microcontroller. The control pins (RS, R/W and EN) are connected to port P3 pins P3^0, P3^1 & P3^6 respectively. CIRCUIT DIAGRAM [pic] LIST OF  COMPONENTS COMPONENT |QUANTITY | |1) General PCB |1 | |2) 16Ãâ€"2  LCD Display |1 | |3) Micro controller base |1 | |4) 10uf/10v capacitor |1 | |5) 8T89C51 micro controller |1 | |6) 12MHz Crystal oscillator |1 | |7) 10k Preset |1 | |8) 2 pin Switches |6 | |9)7805 voltage regulator |1 | |10) 10k Resistor |1 | COMPONENTS KA 7805 (Voltage Regulator) Features: ? Output Current up to 1A ? Output Voltage of 5 Thermal Overload Protection ? Short Circuit Protection ? Output Transistor Safe Operating Area Protection Description: 7805 is a voltage regulator integrated circuit. It is a member of 78xx series of fixed linear voltage regulator ICs. The voltage source in a circuit may have fluctuations and would not give the fixed voltage output. The voltage regulator IC maintains the output voltage at a constant value. The xx in 78xx indicates the fixed output voltage it is designed to provide. 7805 provides +5V regulated power supply. Capacitors of suitable values can be connected at input and output pins depending upon the respective voltage levels. Pin Connections (Front View): Pin No |Function |Name | |1 |Input voltage (5V-18V) |Input | |2 |Ground (0V) |Ground | |3 |Regulated output; 5V (4. 8V-5. 2V) |Output | AT89C51: AT89C51 is an 8-bit Microcontroller and belongs to Atmel's 8051 family. ATMEL 89C51 has 4KB of Flash programmable and erasable read only memory (PEROM) and 128 bytes of RAM. It can be erased and program to a maximum of 1000 times. In 40 pin AT89C51, there are four ports designated as P1, P2, P3 and P0. All these ports are 8-bit bi-directional ports, i. e. , hey can be used as both input and output ports. Except P0 which needs external pull-ups, rest of the ports have internal pull-ups. When 1s are written to these port pins, they are pulled high by the internal pull-ups and can be used as inputs. These ports are also bit addressable and so their bits can also be accessed individually. Port P0 and P2 are also used to provide low byte and hi gh byte addresses, respectively, when connected to an external memory. Port 3 has multiplexed pins for special functions like serial communication, hardware interrupts, timer inputs and read/write operation from external memory. AT89C51 has an inbuilt UART for serial communication.It can be programmed to operate at different baud rates. Including two timers & hardware interrupts, it has a total of six interrupts. Pin Diagram:- [pic] FEATURES OF 8951 1) 8051 have 128 bytes of RAM 2) 8051 have 128 user defined flags 3) it consist of 16 bit address bus 4) it also consist of 3 internal and two external interrupts 5) less power usage in 8051 with respect to other micro-controller 6) it consist of 16-bit program counter and data pointer 7) 8051 can process 1 million one-cycle instructions per second   8) it also consist of 32 general purpose registers each of 8 bits 9) ROM on 8051 is 4 Kbytes in size 10) it also consist of Two 16 bit Timer/ CounterLCD: LCD (Liquid Crystal Display) scree n is an electronic display module and find a wide range of applications. A 16Ãâ€"2 LCD display is very basic module and is very commonly used in various devices and circuits. These modules are preferred over seven segments and other multi segment LEDs. The reasons being: LCDs are economical; easily programmable; have no limitation of displaying special & even custom characters (unlike in seven segments), animations and so on. A 16Ãâ€"2 LCD means it can display 16 characters per line and there are 2 such lines. In this LCD each character is displayed in 5Ãâ€"7 pixel matrix. This LCD has two registers, namely, command and data. The ommand register stores the command instructions given to the LCD. A command is an instruction given to LCD to do a predefined task like initializing it, clearing its screen, setting the cursor position, controlling display etc. The data register stores the data to be displayed on the LCD. The data is the ASCII value of the character to be displayed on th e LCD. Pin Diagram:- [pic] |Pin No |  Function |  Name | |1 |Ground (0V) |Ground | |2 |Supply voltage; 5V (4. 7V – 5. V) |  Vcc | |3 |Contrast adjustment; through a variable resistor |  VEE | |4 |Selects command register when low; and data register when high |Register Select | |5 |Low to write to the register; High to read from the register |Read/write | |6 |Sends data to data pins when a high to low pulse is given |Enable | |7 |8-bit data pins |DB0 | |8 | |DB1 | |9 | |DB2 | |10 | |DB3 | |11 | |DB4 | |12 | |DB5 | |13 | |DB6 | |14 | DB7 | |15 |Backlight VCC (5V) |Led+ | |16 |Backlight Ground (0V) |Led- | PROGRAM TO MAKE A VOTING MACHINE USING LCD #include #define msec 50 #define lcd_data_str_pin P2 sbit rs = P3^0; //Register select (RS) pin sbit rw = P3^1; //Read write(RW) pin sbit en = P3^6; //Enable(EN) pin sbit ini_pin = P1^0; // Start voting pin sbit stop_pin = P1^5; // Stop voting pin sbit candidate_1=P1^1; //Candidate1 sbit candidate_2=P1^2; //Candidate2 sb it candidate_3=P1^3; //Candidate3 sbit candidate_4=P1^4; //Candidate4 int max = 0; int carry = 0; int arr[4]; int vote_amt[3],j; unsigned int vote_1,vote_2,vote_3,vote_4; void delay(int delay_time) // Time delay function { int j,k; for(j=0;j

Radicalism of the American Revolution

Essay 1 â€Å"Radical†, a term generally defined by many as an event or action that fundamentally changes the political, cultural, and/or economic nature of a society. The American Revolution was a time of great change within the structure of society, greatly transforming certain parts of America, yet leaving other parts relatively unchanged over the course of the Revolutionary period. When asked whether or not I consider the Revolution to be â€Å"radical†, I can give no absolute yes or no response.Instead I will have to take more of a â€Å"grey area† approach to the question and say a bit of both yes and no, because although the revolution did change quite a bit, there were still areas it was unable to change. In my opinion, I would say the American Revolution was â€Å"radical†, but only to a point. Some of the most important changes that the Revolution did make in American society were focused heavily on expanding and redefining political freedom thro ughout the country, and establishing religious tolerance. One important way that the revolution did not change the American society was in social hierarchy.Prior to the American Revolution, politics consisted of many voting, but few actually holding any kind of political power, those who did have power not listening to voters, no parties, and few public political arguments. During the Revolution, however, many Americans had a much more powerful voice in politics. This newfound power was due to an ending of old governments and authority, and the fundamental â€Å"need to reinstitute legitimate governments†. Election campaigns also became very public arguments over what the government â€Å"should† be, this is very different than what the political scene was in post-Revolution Colonial America.Some of the most radical movements can be seen in the Revolution in Pennsylvania. In Pennsylvania, the pro-independence radical took control, abolishing such political offices as g overnor. The issue of voting rights was also a very contentious subject in politics. John Adams believed that the â€Å"common rabble† of men in the country had no â€Å"judgment of their own†, and the removal of a property qualification to vote would â€Å"confound and destroy all distinctions, and prostrate all ranks to one common level†.Pennsylvania, for one abolished the property qualification for voting, but retained the tax payment qualification, whereas other states did away with both. Prior to the Revolution, only a few colonies embraced religious tolerance, those being Rhode Island and Pennsylvania. Most of the colonies in the country still had established state churches. However, colonists began to regularly associate religious freedom with â€Å"liberty† and evangelicals particularly supported this movement towards religious liberty, having suffered much oppression, and believing that â€Å"government corrupted religion†.An assault on st ate churches developed with The Elites, a. k. a. , Founding Fathers agreeing that religion could be potentially dangerous when apart of government. This â€Å"Enlightened† religion argued that religion had often supported unjust governments. Most of them would have been Deists. Deism, a popular belief among elites in the 1700s, held belief in God, but that he was rarely and distantly involved in human affairs, and viewed many Christian beliefs as superstition.Thomas Jefferson in his Notes on Virginia, 1782 saying that â€Å"The whole history of these books is [the Gospels] is so defective and doubtful that it seems vain to attempt minute enquiry into it†. The Bill for Establishing Religious Freedom was a Virginia bill introduced by Thomas Jefferson in 1779. The bill eliminated religious requirements for voting and office-holding, eliminated government finance for religion, and barred the state from forcing participation in religion. One important way that the Revolutio n did not change the American Society was in social hierarchy.Although the American Revolution changed many things, it still left some unchanged, like the much higher sociopolitical power of the upper class aristocrats within the country. The social classes were arranged from highest to lowest as such: Upper class, merchants, tradesmen, farmers, working men, indentured servants, slaves, and finally Indians. Not much had changed since Colonial America with the wealthy upper class controlling much of everything from politics to religion. Slavery continued, women had no rights whatsoever, and the system was simply not open to all white men yet.Wealth always made a difference, as it usually does. They were the land owners, the voters, the senators and congressmen. Normal people couldn't be or do any of these things without having the money and success. In conclusion, the American Revolution, in my opinion, can be seen as partly â€Å"radical† and partly not. Similar to many other revolutions, it could not have changed every single thing overnight, and in fact, it did not. But there is no denying that, at least then, it did radically change things in the country, but also left some the same.

The Vs. Education Is There A Correlation - 1572 Words

ntelligence vs Education: Is there a correlation? Intelligence comes from the latin verb intelligere which means to comprehend or perceive. Intelligence is a very difficult word to describe. The average person would just say that it s how smart you are. But what exactly does it mean to be smart? Is it how fast you can add, how could learn something, or what? If you asked a million from people you would probably get a million and one different answers.That s one of if not the main challenge in judging and evaluating education. Education is in its most basic form learning something. The origin of the word education comes from the Latin word Ä“ducÄ tiÃ…  which means (A breeding, a bringing up, a rearing) from Ä“dÃ… «cÃ…  (I educate, I train).†¦show more content†¦These days how much education you have and where you go to school is a the main focus. No job wants an employee who is substandard in their education, believing that the higher level education means more prod uctive and overall better employees. In a study conducted on teens in high school many of them reported being under stress mainly related to school. The statistics reported that 59% of the students said time managing is a somewhat or very significant stressor; 40% say they neglected responsibilities at home because of stress; 21% say they neglected work or school because of stress; 32% say they experience headaches because of stress; 26% report changes in sleeping habits; 26% report snapping at or being short with classmates or teammates when under stress. One student even commented The last two years in high school have been the most stressful for me and my friends, we have to do everything and be perfect for colleges and we have a big workload. Most of the time we talk about how stressed we are. (Sharon Jayson) With all this stress it isn t surprising that many teens turn to suicide, being the second leading cause of death in people ages 10-18. In 2013 the amount of teens who considered suicide was 13% while 5178 teens killed themselves in 2012 in the US alone. Although it is almost impossible to isolate the main reason why they did it most research points to academic stress and bullying. Madison Holleran who attended