"Alcohol and caffeine on daphnia" Essays and Research Papers

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    Extraction of Caffeine from Tea Leaves Marc Tugaoen‚ Kristine Vanzuela‚ Rafael Villanueva‚ Justeen Wong Department of Chemistry‚ University of Santo Tomas‚ Manila‚ Philippines Abstract This experiment has been divided into 4 set-ups‚ first was the solid-liquid extraction‚ next was the liquid-liquid extraction‚ then the sublimation and last was the melting point determination. The solid-liquid and liquid-liquid extraction were both done during the first meeting‚ the DCM layer was filtered and

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    Nicoleta Nedelcu Caffeine-induced effects on heart rate in zebrafish embryos and possible mechanisms of action Observation Caffeine is found in coffee‚ tea leaves‚ cocoa beans‚ and kola nuts. It is used in prescription and over the counter drugs. It increases blood pressure‚ mental alertness‚ and gastrointestinal motility. Cardiovascular development with caffeine and other small molecules can be studied relatively easy using zebrafish. The cardiovascular system is complete in two days after fertilization

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    of alkaloid caffeine from tea leaves Date Submitted: September 3‚ 2014 Abstract Caffeine is one of the main constituents of tea leaves. In this experiment‚ 0.0039 g of pure caffeine was isolated from tea leaves. This was done through solid-liquid extraction followed by multiple liquid-liquid extraction. Then crude material obtained was then purified by sublimation. The isolated caffeine was subjected to thin layer chromatography (TLC) together with a standard caffeine. The Rf value

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    Caffeine‚ the stimulant in coffee‚ has been called “the most widely used psychoactive substance on Earth .” Synder‚ Daly and Bruns have recently proposed that caffeine affects behavior by countering the activity in the human brain of a naturally occurring chemical called adenosine. Adenosine normally depresses neuron firing in many areas of the brain. It apparently does this by inhibiting the release of neurotransmitters‚ chemicals that carry nerve impulses from one neuron to the next. Like

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    This I Believe I believe in caffeine. I believe in caffeine because it keeps me alert‚ not quite awake‚ but alert. After a full night of studying‚ cramming on procrastinated homework‚ or just refusing to go to sleep‚ caffeine keeps you alert enough to be aware of the happenings of your day. But why would a 17 year old girl believe in caffeine‚ a chemical usually depended upon by truck drivers and stressed out adults working a daily 9-5? This is because of a 17 year old girl’s awareness of the

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    widely used psychoactive drug found in many drinks‚ such as coffee‚ tea and cola. Caffeine is naturally present in the leaves and seeds of a variety of plants. Consuming caffeine has significant physiological effects on your body--one being its direct effect on your heart rate. Features Once consumed‚ caffeine enters your blood from the stomach and small intestine and begins to stimulate your central nervous system. Caffeine stimulates receptors located in cells within your heart to increase your heart

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    Extraction of caffeine from tea bags ABSTRACT Caffeine extraction from the commercial tea leaves (Lipton Yellow Label Tea) that was done is multiple extraction. 4 tea bags   were used in the experiment; tea leaves were weighed having 8.5333 grams. The leaves were boiled in a beaker with 150ml of water; the aqueous tea extract was transferred in a seperatory funnel mixed with DCM (20ml)‚ done thrice. The DCM layer was washed with 20ml 6M NaOH in the seperatory funnel; the organic layer was dried

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    Abstract: Caffeine‚ (C8 H10 N4 O2) a white‚ crystalline alkaloid known as a nervous system stimulant found commonly in tea leaves and coffee‚ can be extracted using the method of sublimation with the use of Methylene Chloride (CH2Cl2) and Sodium Hydroxide; both can repeatedly rinse the green (unroasted) coffee beans from the caffeine. Keywords: Caffeine‚ Methylene Chloride‚ Sodium Hydroxide‚ Anhydrous Sodium Sulfate I. Introduction Caffeine is an alkaloid of the methylxanthine family. Its chemical

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    Effects of Caffeine and Nicotine on Lumbriculus variegatus INTRODUCTION An experiment was conducted to study and explore the circulatory system by exposing Lumbriculus variegatus‚ black worms‚ to household drugs. Lumbriculus variegatus was chosen as the experimental organism because of their transparent bodies and their simple physiology. Their transparent bodies help the experimenters to easily see their pulse. Another reason for choosing this specific organism is their body structure—large

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    Experiment 11b: Isolation of Caffeine from a Tea Bag October 12‚2012 Purpose: The objective of this experiment is to extract caffeine from tea bags using the method of extraction. After the caffeine is extracted it is then compared to the nutritional facts amount per serving on the tea bags box. Supplies: Glassware: 1. 50.0 m L graduated cylinder 2. 150.0 mL beaker 3. 2-glass stirring rod 4. 6-test tubes 5. 2-glass pipettes 6. 2-50.0 mL Erlenmeyer flasks 7. glass funnel Hardware:

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