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Saturday, 17 May 2014

How to Improve Your Memory While Studying


Kara doesn't much like American history, and she's put off studying for the final exam on Friday. On Thursday night, she stays up and reads over each chapter from beginning to end. But when she sits down to take the test the next day, she can't seem to remember a thing that she read. What happened?

Kara went about studying for the test in the wrong way. Simply sitting down the night before and reading through the entire chapter, without questioning, commenting, or categorizing, with the vague hope that she'd remember what she read, is pretty much like throwing a batch of file cards into a box and hoping to remember what's on them later.

Unfortunately, Kara's study methods are pretty common among students. Studying for a test just by reading over the information one time will give you a retention rate of only about 20 percent, no matter how smart you are.
Fortunately, by learning some simple retention strategies, you can boost your recall to more than 80 percent. Memory strategies can help you learn spelling, vocabulary, a foreign language, names of historical figures, states and capitals, scientific terms, cities and primary products, U.S. presidents, foreign kings, basic math -- just about everything a person needs to learn in school or on the job.

There are three main ways to boost your memory of basic facts:
by practicing active recall during learning
by periodic reviews of the material
by overlearning the material beyond the point of bare mastery
Involve Yourself in Reading!Instead of just reading, you need to read and think about what you're reading. Here are some suggestions for doing just that:

Think of questions for yourself before, during, and after the reading session.
Ask yourself what is happening next, why it's happening, and what would happen if one event or fact was different.
Note what interests you. Take a moment to make a mental comment out loud.
Train yourself to summarize, a section at a time. What are the main points in the text you just read? What are the logical conclusions?
Visualize as You ReadTry to imagine yourself in the place you're reading about, or try to imagine yourself doing what you're studying. Include yourself in images that you build in your mind. If you're reading about the Civil War, picture yourself on the battlefield. Why are you there? What is the enemy doing, and why? The better you can put yourself into a scene, the better you'll remember what you are reading.

Of course, it's much easier to visualize yourself in a battle than it is to link yourself to the major exports of Peru. Instead of just trying to visualize "wool, wheat, and corn," imagine you're a Peruvian farmer raising sheep and growing wheat and corn. This will work with just about anything, except perhaps for numbers and dates.
Take a Note!Taking notes won't help you if you scribble down the words in class without thinking about what you're writing, which is unfortunately the way too many students take notes.

The best way to take notes in class:
Take them carefully while thinking about their content.
Review them as you write.
Summarize whenever possible. Isolate what's important and discard the rest while you're writing.
Don't take down every word your teacher says.

PQRST MethodOne of the most popular techniques for remembering written material is the PQRST method: Preview, Question, Read, State, and Test. Memory experts think this works better than simple rehearsal because it provides you with better retrieval cues.

Preview. Skim through the material briefly. Read the preface, table of contents, and chapter summaries. Preview a chapter by studying the outline and skimming the chapter (especially headings, photographs, and charts). The object is to get an overview of the book or chapter (this shouldn't take more than a few minutes).

Question. Ask important questions about the information you're reading. If the chapter includes review questions at the end, read them before you begin reading the chapter and try to keep them in mind as you go. What are the main points in the text? How does the action occur? Read over the paragraph headings and ask yourself questions about them.

Read. Now read the material completely, without taking notes. Underlining text can help you remember the information, provided you do it properly. The first time you read a chapter, don't underline anything (it's hard to pick out the main points the first time through). Most people tend to underline way too many things, which isn't helpful when you want to be able to go back later and review important points. Instead, read over one section and then go back and, as you work your way through each paragraph, underline the important points. Think about the points you're underlining.

State. State the answers to key questions out loud. Reread the chapter and ask yourself questions and answer them out loud. Read what you've underlined out loud, and think about what you're saying. You should spend about half your studying time stating information out loud.
Test. Test yourself to make sure you remembered the information. Go through the chapter again and ask questions. Space out your self-testing so you're doing it during a study session, after a study session, and right before a test. If you'd like, enlist the help of a friend to quiz you.
Make the Most of StudyingWhen you study is almost as important as how you study. It's better to schedule several shorter study sessions rather than one marathon all-nighter. This is probably because you can only concentrate for a certain period of time. If you try to study in one long session, you won't be able to maintain your concentration throughout. Breaks help you consolidate what you've learned.
On the other hand, you can overdo the short sessions as well -- scheduling too many short study sessions can be worse than cramming all of your studying into one marathon session. The trick is to determine the optimum length of a study session and how many sessions work best for you and for the material. Research suggests that difficult information or inexperienced students require shorter sessions for best results. If you have several subjects to study, it's better to separate them and spread them out over several days. You should also vary your learning methods: Take notes one day, make an outline the next, recite information out loud during the third study session.

You'll also want to avoid interference when you study. If you're boning up for a math test, don't close the math book and then read magazines, watch TV, and listen to music before going to bed. Study, then go to bed, so nothing else can interfere with what you've learned. Studies have also shown that sleeping between studying and testing is the best way to do well on a test. A person who sleeps right after studying will remember more than someone who stays awake.

It's also true that other activities between studying and the test will influence how well you remember. If you've spent several hours studying French, you shouldn't then study Latin before going to bed. In fact, if you have two very similar subjects to study, it's best not to study them in the same location.

First-Letter Cuing (Acronyms)The use of the first letter of a word as a cue to remembering the word itself can be helpful in remembering material. This cueing usually employs acronyms -- making a word out of the first letters of the words to be remembered. For example, it's possible to remember the Great Lakes using the acronym HOMES (Huron, Ontario, Michigan, Erie, Superior). Another related type of first-letter cueing is the acrostic, discussed previously, in which the first letters in a series of words form a word or phrase. For example, names of the strings of the viola (CGDA) can be remembered by the acrostic: Cats Go Down Alleys.

Because the acronym system is so effective, most organizations and governmental bodies make use of first-letter cueing: NATO (North Atlantic Treaty Organization) or AA (Alcoholics Anonymous). Some acronyms are so well known that the original full name has been all but forgotten, as in "scuba" (Self-Contained Underwater Breathing Apparatus) gear.

The only problem with first-letter cueing is the propensity to forget what the strategy has been used for. Therefore, it's a good idea to make the association remind you of the information to be remembered. Imagine HOMES floating on the Great Lakes, so that when you want to think of the names of all the lakes, the image of HOMES will return to you and with it, the first letter of each of the lakes.
Peg and LinkBoth the peg and linking systems that we discussed earlier also work well with studying school subjects. Review those methods and try practicing with them, especially for rote learning and memorization (such as a list of U.S. Presidents or the amendments to the Constitution).

http://health.howstuffworks.com/human-body/systems/nervous-system/how-to-improve-your-memory10.htm

Friday, 9 May 2014

THE HEALTH BENEFITS OF STRAWBERRIES


The health benefits of strawberries include improved eye care, proper brain function, relief from high blood pressure, arthritis, gout and various cardiovascular diseases. The impressive polyphenolic and antioxidant content of strawberries make them good for improving the immune system, preventing against various types of cancers, and for reducing the signs of premature aging.
Introduction to Strawberries
These berries, with their tempting looks and spectacular taste, secured their place in the list of favorite fruits a long time ago. Strawberries have the common scientific name of Fragaria, but there are different suffixes for different varieties, such as Fragaria Vesca for wild strawberry, and Fragaria Orientalis for Eastern Strawberries, among others. Strawberries grow in bushes and are one of the most delicious seasonal fruits that also boost your health.
Strawberries are often associated as a European fruit, and to some degree, they are. They were used back in Roman times, and were first cultivated as a garden fruit in France in the 18th Century. However, they were also present in South American cultures much earlier, but since there was also a source of strawberries in Europe, it is usually thought of as being native to that region.
Strawberries are extensively used in food, including in ice creams, jams, jellies, squashes, syrups, confections, baked goods, chocolates and even in medicines for their extraordinarily rich flavor, taste and color. They can also be consumed fresh. We know that all fruits, particularly berries and those with exotic colors, are rich in antioxidants, which means that they are huge boosters to your health and the protection of your organs from toxic attacks.
Nutritional Facts of Strawberries
Strawberries are no exception to this rule; in addition to antioxidants, they have many other nutrients, vitamins, and minerals that contribute to overall health. These include folate, potassium, manganese, dietary fiber, and magnesium. It is also extremely high in vitamin C! Together, these components are responsible for the overwhelming health benefits of strawberries. Let’s explore them in more detail in the section below.
Health Benefits of Strawberries
Let’s explore a bit more about these potential health benefits of strawberries in the more detailed explanations below.
Eye Care: The primary reasons for almost all problems related to the eyes are free radicals or a deficiency of certain nutrients. With increased age and a lack of these protective nutrients, the harmful oxidants or free radicals can cause heavy damage on our eyes, such as excessively dry eyes, degeneration of the optical nerves, macular degeneration, vision defects and increased susceptibility to infections as well.
Antioxidants such as flavonoids, phenolic phytochemicals, and elagic acid, all of which are present in strawberries, can help to avoid these situations to a large extent. One more condition strawberries can fix is is ocular pressure, meaning the pressure within the eyes. Any disturbance in this pressure can be very harmful for the eyes. Strawberries are helpful because they contain potassium, which helps to maintain the correct pressure.
Immune System: The immune system is our body’s first line of defense against infections, microbial action, and a wide variety of other potentially damaging and dangerous conditions that can affect our body. Vitamin C is a huge booster for the immune system and has long been known as a helpful cure for common colds and coughs, along with its impact on any other infections as well. Vitamin C also stimulates the activity of white blood cells, the body’s first line of defense against toxins and foreign bodies. Vitamin C is also an antioxidant, which means that it neutralizes free radicals, the harmful byproducts of cellular metabolism that are constantly created in our body. These free radicals are responsible for mutating the DNA of healthy cells into sick or cancerous cells, and are subsequently responsible for a number of diseases, including heart disease and various cancers. A single serving of strawberries has approximately 150% of your daily requirement of vitamin-C!
Arthritis and Gout: The degeneration of muscles and tissues, the drying up of the fluid which helps increase mobility of the joints, and the accumulation of toxic substances and acids (such as uric acid) in the body are some of the ill effects of free radicals. These are the primary causes of arthritis and gout, two extremely irritating and debilitating conditions.
Strawberries, with their impressive content of antioxidants and detoxifiers, can effectively help eliminate such health hazards forever. It is a famous saying in India that a serving of any fruit every day will remove the “rust” from the joints. This old adage is definitely true for strawberries, since it does have very powerful anti-inflammatory abilities to ease the inflammation and associated pain from these types of conditions.
Cancer: Vitamin-C, folate, anthocyanins, quercetin and kaempferol are just a few of the many flavonoids in strawberries which possess excellent antioxidant and anticarcinogenic properties. Together, they form an excellent line of defense to fight cancer and tumor growth. The daily intake of strawberries is connected to a drastic reduction in the presence and metastasis of hazardous cancer cells.
Brain Function: Unfortunately, it is very common for old people to begin losing their memory and control over certain activities, muscles, and limbs. This is due to either the natural or premature aging of their brain and nervous system. Actually, free radicals are the agents responsible for signs of aging because they have an adverse effect on both of these systems. Due to the activity of free radicals, the brain tissues start degenerating and the nerves become weaker. Luckily, strawberries can help you avoid these untimely conditions in life.
The vitamin-C and the phytochemicals in strawberries neutralize the effects of these oxidants and rejuvenate the system. Furthermore, strawberries are rich in iodine as well, which is very helpful for regulating the proper functioning of the brain and nervous system. Potassium, which is found in significant quantities in strawberries, also has been linked to improved cognitive function by increasing the blood flow to the brain. Research studies on students have shown that when potassium levels of high, concentration, memory, and recall abilities seem to be strengthened in test-taking. There is a good reason why bananas and strawberries are considered “brain food”!
High Blood Pressure: Strawberries are rich in potassium and magnesium content, both of which are effective in lowering high blood pressure caused by sodium and various other risk factors. Potassium is a vasodilator, meaning that it reduces hypertension and the rigidity of arteries and blood vessels, thereby lowering blood pressure, easing the flow of blood to various parts of the body, thereby oxygenating them and keeping them functioning at their full potential.
Heart Disease: High fiber content, folate, no fats, and high levels of antioxidants such as vitamin-C and those phytochemicals  form an ideal cardiac health pack, as they effectively reduce cholesterol in the arteries and vessels. Some members of the vitamin-B family present in strawberries also strengthen the cardiac muscles and lead to better functioning of the heart.
Other Benefits: Folate is known to protect from birth defects. Phytonutrients also have anti-inflammatory properties.
Perhaps most importantly, strawberries and all of the associated foods that contain strawberries are delicious as well. Next time you are looking for something sweet, bite into some juicy strawberries and enjoy the benefits they have in store for you!
http://www.organicfacts.net/health-benefits/fruit/strawberries.html

Wednesday, 19 March 2014

Blood Alchol Content

As blood passes through the arteries in the lungs,an equilibrium is established between the alcohol in one's blood and the alcohol in one's breath. So if the concentration of one is known, the concentration of the other can be estimated. The test that law enforcement agencies use to approximate a person's blood alcohol level is based on the oxidation of breath ethanol. The test employs a sealed glass tube that contains the oxidizing agent ( sodium dichromate dissolved in sulfuric acid ) impregnated onto an inert material. The ends of the tube are broken off, and one end of the tube is attracted to a mouthpiece and the other to a balloon-type bag. The person undergoing the test blows into the mouthpiece until the bag is filled with air.

Any ethanol in the breath is oxidized as it passes through the column. When ethanol is oxidized, the red-orange dichromate ion is reduced to green chromic ion .
Thr greater the concentration of alcohol in the breath, the farther the green color spreads through the tube.

If the person fails this test determined by the extent to which the green color spreads through the tube a more accurate Breathalyzer test is administered. The Breathalyzer test also depends on the oxidation of breath ethanol, but it provides more accurate results because it is quatitative . In the test , a known volume of breath is bubbled through an acidic solution of sodium dichromate, and the concentration of the green chromic ion is measured precisely with a spectrophotometer.

Saturday, 22 February 2014

Blood Pressure

Blood pressure (BP), sometimes referred to as arterial blood pressure, is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, blood pressure varies between a maximum (systolic) and a minimum (diastolic) pressure.The blood pressure in the circulation is principally due to the pumping action of the heart. Differences in mean blood pressure are responsible for blood flow from one location to another in the circulation. The rate of mean blood flow depends on the resistance to flow presented by the blood vessels. Mean blood pressure decreases as the circulating blood moves away from the heart through arteries and capillaries due to viscous losses of energy. Mean blood pressure drops over the whole circulation, although most of the fall occurs along the small arteries and arterioles. Gravity affects blood pressure via hydrostatic forces (e.g., during standing), and valves in veins, breathing, and pumping from contraction of skeletal muscles also influence blood pressure in veins.

Blood pressure without further specification usually refers to the systemic arterial pressure measured at a person's upper arm and is a measure of the pressure in the brachial artery, the major artery in the upper arm. A person’s blood pressure is usually expressed in terms of the systolic pressure over diastolic pressure and is measured in millimetres of mercury (mmHg), for example 120/80. It is also expressed as the amount over normal atmospheric pressure (760 mmHg), so a blood pressure of 120 mmHg would actually be 880 mmHg of true pressure.

Blood pressure varies in healthy people and animals, but its variation is under control by the nervous and endocrine systems. Blood pressure that is pathologically low is called hypotension, and that which is pathologically high is hypertension. Both have many causes and can range from mild to severe.


Monday, 17 February 2014

Anesthetics

Because diethyl ether ( commonly known simply as ether ) is a short-lived muscle relaxant, it has been widely used as an inhalation anesthetic. However, because it takes effect slowly and has a slow and unpleasant recovery period, other compounds, such as enflurane, isoflurane, and halothane, have replaced ether as an anesthetic. Diethyl ether is still used where there is a lack of trained anesthesiologists, because it is the safest anesthetic to administer by untrained hands. Anesthetics interact with the nonpolar molecules of cell membranes, causing the membranes to swell, which interferes with their permeability.

sodium pentothal ( also called thiopental sodium ) is commonly used as aintravenous anesthetic. The onset of anesthesia and the loss of consciousness occur within seconds of its administration. Care must be taken when administrating sodium pentothal because the dose for effective anesthesia is 75% of the lethal dose. Because of its toxicity, it cannot be used as fore an inhalation anesthetic is administered. Propofol is an anesthetic that has all the properties of the "perfect anesthetic ": It can be used as the sole anesthetic by intravenous drip, it has a rapid and pleasant induction period and a wide margin of safety, and recovery from the drug also is rapid and pleasant.

Friday, 14 February 2014

Lead Compound

The goal of the medicinal chemist is to find compounds that have potent effects on given diseases with minimum side effects. In other words, a drug must react selectively with its target and have minimal negative effects. A drug must get to the right place in the body, at the right concentration, and at the right time. Therefore, a drug must have the appropriate solubility to allow it to be transported to the target cell. If it is taken orally, the drug must be insensitive to the acid conditions of the stomach, and it also must resist enzymatic degradation by the liver before it reaches its target. Finally, it must eventually be either excreted as is or degraded to harmless compounds that can be excreted.

Medicinal agents used by humans since ancient Times provided the starting point for the development of our current arsenal of drugs . The active ingredients were isolated from herbs , berries, roots, and bark used in traditional medicine. Foxglove, for instance, furnished digitoxin, a cardiac stimulant. The bark of the cinchona tree yielded quinine for relief from malaria. Willow bark contains salicylates used to control fever and pain. The sticky juice of the oriental opium poppy provided morphine for severe pain and codeine for the control of a couch. By 1882, more than 50 different herbs were commonly used to make medicines. Many of these herbs wrere grown in the gardens of religious establishments that treated the sick.


Scientists still search the world for plants and berries and the oceans for flora and fauna that might yield new medicinal compounds . Taxol, a compound isolated from the bark of the Pacific yew tree, is a relatively recently recognized anticancer agent.
Once a naturally occurring drug is isolated and its structure determined, it can serve as a prototype in a search for other biologically active compounds . The prototype is called a lead compound ( i.e., a compound that plays a leading role in the search ). Analogs of the lead compound are synthesized in order to find one that might have improved therapeutic properties or fewer side effects. The analog may have a different substituent than the lead compound , a branched chain instead of a straight chain , or a different ring system. Changing the structure of the lead compound is called molecular modification.

Sunday, 9 February 2014

Vitamin B1

Christiaan Eijkman (1858-1930) was a member of a medical team that was sent to the East Indies to study beriberi in 1886. At that time , all diseases are thought to be caused by microorganisms. When microorganisms that caused beriberi could not be found, the team left the East Indies .

Eijkman stayed behind to become the director of a new bacteriological laboratory. In 1896, Eijkman accidentally discovered the cause of beriberi when he noticed that the chickens used in the laboratory had developed symptoms characteristic of the disease. He found that the symptoms had developed when a cook had started feeding the chickens rice meant for hospital patients. The symptoms disappeared when a new cook resumed feeding chicken feed to the chickens.

Later it was recognized that thiamine ( vitamin B1) is present in rice hulls but not in polished rice. For this work, Eijkman shared the Nobel Prize in physiology or medicine with Frederick Hopkins.



Saturday, 8 February 2014

VITAMIN C

Vitamin C is an antioxidant because it prevents oxidation reactions by radicals. We have seen that vitamin C traps radicals formed in aqueous environments. Not all the physiological functions of vitamin C are known. What is known, though, is that vitamin C is required for the synthesis of collagen, which is the structural protein of skin , tendons, connective tissue, and bone. If vitamin C is not present in the diet ( it is abundant in citrus fruits and tomatoes ), lesions appear on the skin , severe bleeding occurs about the gums , in the joints, and under the skin , and wounds heal slowly. The disease caused by a deficiency of vitamin C is known as scurvy. British sailors who shipped out to sea after the late 1700s were required to eat limes to prevent scurvy. This is how they came to be called "limeys" . Scurvy was the first disease to be treated by adjusting the diet. Scorbutus is Latin for "scurvy" ; ascorbic, therefore, means"no scurvy".

Thursday, 6 February 2014

Plastic Polymers and Food Safety

When plastics are recycled, the various types must be separated from one another. To aid in the separation, many states require manufacturers to include a recycling symbol on their products to indicate the type of plastic. 

You are probably familiar with these symbols, wich are found on the bottom of plastic containers. The symbols consist of three arrows around one of seven numbers; an abbreviation below the symbol indicates the type of polymer from wich the container is made. 


The lower the number in the middle of the symbol,the greater is the ease with wich the material can be recycled: 1 (PET) stands for poly ( ethylene terephthalate), 2(HDPE) for high-density polyethylene, 3(V) for poly ( vinyl chloride ), 4 (LDPE) for low-density polyethylene, 5 (PP) for polypropylene, 6 (PS) for polystyrene, and 7 for all other plastics.


Plastic Container Symbols for Food Grade Plastics

Types of Plastics and Food Safety By Plastic Number
Please reference Graphics for Quick View of Numbers to look for embedded into plastic products to help determine their safety.
1. PETE: Polyethylene terephthalate ethylene, used forsoft drink, juice, water, detergent, cleaner and peanutbutter containers.
2. HDPE: High density polyethylene, used in opaque plastic milk and water jugs, bleach, detergent and shampoo bottles, and some plastic bags.
3. PVC or V: Polyvinyl chloride, used for cling wrap, plastic squeeze bottles, cooking oil and peanut butter containers, and detergent and window cleaner bottles.
4. LDPE: Low density polyethylene, used in grocery store bags, most plastic wraps, Ziplock bags and some bottles.
5. PP: Polypropylene, used in most Rubbermaid, deli soup, syrup and yogurt containers, straws and other clouded plastic containers, including baby bottles.
6. PS: Polystyrene, used in styrofoam food trays, egg cartons, disposable cups and bowls, carry-out containers and opaque plastic cutlery.
7. Other: This is a catch-all category for plastics that don’t fit into the #1-6 categories. It includes polycarbonate, bio-based plastics, co-polyester, acrylic, polyamide and plastic mixtures like styrene-acrylonitrile resin (SAN). Number 7 plastics are used for a variety of products like baby bottles and “sippy” cups, baby food jars, 5-gallon water bottles, “sport” water bottles, plastic dinnerware and clear plastic cutlery.

What to look for on Plastic Containers
Here are some things to keep in mind when using the microwave:
  • Most takeout containers, water bottles, and plastic tubs or jars made to hold margarine, yogurt, whipped topping, and foods such as cream cheese, mayonnaise, and mustard are not microwave-safe.
  • Microwavable takeout dinner trays are formulated for one-time use only and will say so on the package.
  • Don’t microwave plastic storage bags or plastic bags from the grocery store.
  • Before microwaving food, be sure to vent the container: Leave the lid ajar, or lift the edge of the cover.
  • Don’t allow plastic wrap to touch food during microwaving because it may melt. Wax paper, kitchen parchment paper, or white paper towels are alternatives.
  • If you’re concerned about plastic wraps or containers in the microwave, transfer food to glass or ceramic containers labeled for microwave oven use.



Our homes are full of plastic, and the kitchen is no exception. The problem: Chemicals in plastic containers and other kitchenware may leach into the foods or drinks that they’re holding. Scientific evidence suggests that some of these chemicals may be harmful to people, especially infants and children.
The two best-studied offenders are bisphenol A (BPA) and phthalates. BPA mimics estrogen and has been shown to disrupt hormone and reproductive system function in animals. Research by the National Toxicology Program found a moderate level of concern about its “effects on the brain, behavior and prostate gland in fetuses, infants and children.” Phthalates have been shown to disrupt the endocrine system and have led to malformations in the male reproductive system in animals. Studies in humans have found associations between high phthalate exposure and a variety of health concerns including low sperm quality, high waist circumference and insulin resistance.
Researchers are still debating whether phthalates and BPA actually cause these health problems and, if so, how much exposure is necessary to trigger them. While these issues are being figured out, some experts recommend taking a preventive approach: “Minimize contact of food with problematic plastics as a precautionary measure to protect your health,” suggests Rolf Halden, PhD, adjunct associate professor of environmental health sciences at the Johns Hopkins Bloomberg School of Public Health. Here are six simple tips for reducing your exposure to the potentially harmful chemicals in plastics.
1. Know the code. Look on the bottom of your plastic to find the recycling symbol (a number between 1 and 7 enclosed in a triangle of arrows). The code indicates the type of plastic you are using and can give you important clues about safety. “We generally say 1, 2, 4 and 5 are considered to be the safest,” says Sonya Lunder, senior analyst at the Environmental Working Group. Try to avoid using plastics with 3 or 6, as these leach chemicals that may be harmful. Number 7 is an “other” category that includes BPA-containing plastics called polycarbonates. These plastics, which you should avoid, will have the letters PC printed underneath the 7.
2. Reconsider the microwave. Heat can increase the rate at which chemicals like BPA leach from plastic. Containers labeled “microwave safe” have been tested by the Food and Drug Administration (FDA) and found to leach extremely small amounts, which the FDA has determined to be safe. However, some experts advise people to keep plastic out of the microwave altogether. “I don’t microwave anything in plastic,” says Lunder. “It’s really easy and fast to put my food into a ceramic or glass container and heat it that way.” And never put plastic wrap on top of your food in the microwave, since it can melt. Use wax paper or a paper towel instead.
3. Use it for its intended purpose. Plastics that are designed for single use should only be used once. “Plastic breaks down over time,” Lunder explains. “Some aren’t designed to withstand heating and cooling.” Most plastics with recycling code number 1 are intended for single use, such as disposable water bottles. And that takeout container from six months ago? Toss it. In general they’re fine for refrigerating leftovers, but aren’t designed for heat exposure or long-term use.
4. Wash by hand. Only put plastics into the dishwasher if they have a dishwasher safe label. If you want to be extra-cautious, wash all plastics by hand or use only glass and ceramic plates and dishes. In the dishwasher, plastics are exposed to detergents and heat, which may accelerate the leaching of BPA from food containers.
5. Do not freeze. Only put plastics in the freezer if they have a freezer-safe label. Freezer temperatures can cause plastics to deteriorate, which increases the leaching of chemicals into the food when you take containers out of the freezer to thaw or reheat.
6. Don’t panic. Cutting down on exposure to potentially harmful chemicals in plastics can benefit your health. But as Dr. Halden reminds us, “Many things in your life pose a much higher risk than exposure to plastics, such as smoking, poor diet and even driving a car.”

Ref; 
Essentia Organic Chemistry, Paula Y. Bruice 

Cancer Chemotherapy ; 5-fluorouracil

Cancer is associated with rapidly growing and proliferating cells . Because cells cannot multiply if they cannot synthesize DNA, several cancer chemotherapeutic agents have been developed to inhibit thymidylate synthase. If a cell cannot make thymidine( T ), it cannot synthesize DNA.

A common anticancer drug that inhibits thymidylate synthase is 5-fluorouracil. The enzyme reacts with 5-fluorouracil the same way it reacts with uracil. However, the fluorine substituent causes 5-fluorouracil to become permanently attached to the enzyme (because the base cannot remove a F+ in an elimination reaction) , blocking the active site of the enzyme so it can no longer bind uracil. Therefore, thymidine can on longer be synthesized , and without thymidine, DNA cannot be synthesized.

Unfortunately, most anticancer drugs cannot discriminate between diseased and normal cells. As a result, cancer chemotherapy is accompanied by terrible side affects. However, cancer cells undergo uncontrolled cell division; thus, because they are dividing more rapidly than normal cells, they are harder hit by cancer-fighting chemotheraputic agents.




Ref; Essentia Organic Chemistry, Paula Y. Bruice

Friday, 17 January 2014

The Immortal Life of Henrietta Lacks

Henrietta Lacks (August 1, 1920 – October 4, 1951) (sometimes erroneously called Henrietta LakesHelen Lane or Helen Larson) was an African-American woman who was the unwitting source of cells (from her cancerous tumor) which were cultured by George Otto Gey to create the first known human immortal cell line for medical research. This is now known as the HeLa cell line.




HeLa cell, is a cell type in an immortal cell line used in scientific research. It is the oldest and most commonly used human cell line. The line was derived from cervical cancer cells taken on February 8, 1951, from Henrietta Lacks, a patient who eventually died of her cancer on October 4, 1951. The cell line was found to be remarkably durable and prolific as illustrated by its contamination of many other cell lines used in research.

An immortalised cell line is a population of cells from a multicellular organism which would normally not proliferate indefinitely but, due to mutation, have evaded normal cellular senescence and instead can keep undergoing division. The cells can therefore be grown for prolonged periods in vitro. The mutations required for immortality can occur naturally or be intentionally induced for experimental purposes. Immortal cell lines are a very important tool for research into the biochemistry and cell biology of multicellular organisms. Immortalised cell lines have also found uses in biotechnology.
An immortalised cell line should not be confused with stem cells, which can also divide indefinitely, but form a normal part of the development of a multicellular organism.

Senescence is biological aging is the process of accumulative changes to molecular and cellular structure that disrupts metabolism with the passage of time, resulting in deterioration and eventually bringing about death.

On January 29, 1951, Lacks went to Johns Hopkins Hospital because she felt a knot inside her. She had told her cousins about the knot; they assumed correctly that she was pregnant. But, after giving birth to her fifth child, Joseph, Henrietta started bleeding abnormally and profusely. Her local doctor tested her for syphilis, which came back negative, and referred her to Johns Hopkins.
Johns Hopkins was their only choice for a hospital since it was the only one in proximity to them that treated black patients. Howard Jones, her new doctor, examined Henrietta and the lump in her cervix. He cut off a small part of the tumor and sent it to the pathology lab. Soon after, Lacks learned she had a malignant epidermoid carcinoma of the cervix.
Lacks was treated with radium tube inserts, which were sewn in place. After several days in place, the tubes were removed and she was released from Johns Hopkins with instructions to return for X-ray treatments as a follow-up. During her radiation treatments for the tumor, two samples of Henrietta's cervix were removed—a healthy part and a cancerous part—without her permission. The cells from her cervix were given to Dr. George Otto Gey. These cells would eventually become the HeLa immortal cell line.
In significant pain and without improvement, Lacks returned to Hopkins on August 8 for a treatment session, but asked to be admitted. She remained at the hospital until the day of her death. Though she received treatment and blood transfusions, she died of uremic poisoning on October 4, 1951, at the age of thirty-one. A subsequent partial autopsy showed that the cancer had metastasized throughout her entire body




http://en.wikipedia.org/wiki/Henrietta_Lacks
http://en.wikipedia.org/wiki/Immortalised_cell_line
http://en.wikipedia.org/wiki/Cellular_senescence#Cellular_senescence
http://en.wikipedia.org/wiki/HeLa
 

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