For many years, stress and spicy foods were thought to be the root causes of ulcers (which are holes in the lining, or mucosa, of the stomach).

In 1983, however, Australian physicians Barry Marshall and Robin Wren implicated Helicobacter pylori bacteria as causing the condition. The medical establishment was skeptical until the good doctors took one for the team by ingesting the bacteria - and developing the gastritis inflammation that accompanies ulcers!

Researchers continue to believe that factors such as stress, diet, and heredity play a role in the development of ulcers, since 50% of the population is infected with H. pylori bacteria while only a small percentage have ulcers. Nevertheless, 90-95% of people with ulcers in the stomach, esophagus, and small intestine have the bacteria, and getting rid of the bacteria reduces ulcer recurrence rates to less than 10% per year.

The good news is that antibiotics can now be used to treat the painful condition that affects millions of people every year. The bad news is that there is still no easy cure for stress - except, perhaps, a long vacation to the land down under!

A lot of stomach aches are caused by gas or acid in your stomach. But others are caused by microbes. Shigella is one of the more common culprits! (It is particularly common in developing countries and is a major cause of traveler's diseases.)

Shigella is named after a Japanese researcher named Shiga who discovered the bacterium in 1897. It causes an intestinal tract infection that produces abdominal cramps, fever, and diarrhea.

Shigella is extremely contagious. In fact, it is so contagious that if even 10 individual bacteria ge into your system, yuo can become infected! As a result, over 140 million people are infected by Shigella every year. (It is responsible for 10 to 20 percent of the cases of diarrhea worldwide.)

The most important step to take if you are infected is to stay hydrated - through antibiotics can be used against the bacteria in the more severe cases. Better yet, avoid infection in the fist place by washing your hands a lot!

Experience the beautiful side of biology and chemistry with this unique collection of experiments. Learn how to care for your skin, hair, and nails so they are healthy and radiant. Start by building a foundation in basic dermatology, and then learn about the chemistry of oils, gels, and lotions. Next, mix your own personalized beauty formulas from the cosmetic bases in the kit and natural ingredients from your local market. Finally, learn how to apply your creations to your body, face, lips, and eyes. You will also learn the hygiene and safety necessary for proper skin care.

The kit includes eleven different cosmetics base substances to make personalized makeup, lip gloss, body lotion, face cream, and shower gel. These are real cosmetic-grade substances that are safe, clean, hypoallergenic, and made in Europe by a company that manufactures high-quality commercial cosmetics.

The 32-page, full-color book guides you through the science and history of cosmetics, and gives dozens of beauty recipes and techniques. Ages 12 and up. The cosmetics in this kit were developed humanely, without animal testing.

ò mix your own personalized cosmetics
ò experiment with healthy, all natural beauty recipes
ò find out how to apply makeup like a pro
ò discover what cosmetics are made of
ò study the biology of skin, hair, and nails
ò make gifts for your friends

This ready-to use, erupting model volcano is an educational tool that can be used over and over again. The two halves of the volcano show all the different parts of the volcanic process from the inside out. Learn about the sill, vent, strata, conduit, dike, crust, upper mantle, magma chamber and lower mantle, then test your knowledge on the unlabeled half of the volcano. Then, put the two halves together and watch it erupt!

Bitz Cow Model is a 3-D puzzle which can be put together and displayed on its own stand. Children will learn all about the anatomy of a cow by putting all the "bitz" in the correct place. Contains 29 pieces. Cow stands at approx. 13cm high x 17cm long.

Ages 6 and up

Scissor Lifts are cool machines that are used on building sites to lift a platform horizontally. They are commonly used to reach high places like ceilings with a steady place to work from.

This model uses the same principles as those in real situations, except you use water instead of hydraulic fluid - nice! Once made the Scissor Lift provides an excellent example of how we use technology to reach the top Great for kids to learn about hydraulics, leers and simple machines.

Simple to build in less than an hour, you need only a pair of scissors to make this fun and functional model. Great for kids 8 and up.

Excavators are big machines that are used to dig holes and move earth, and this model uses the same principles as those used in real situations, except you use water instead of hydraulic fluid.

There are many types of excavators and this kit uses a first and third class lever to make the arm and shovel move. Once built, it provides and excellent example of how we use technology to dig things up. Great for kids to learn about hydraulics, levers and simple machines, and to finish small excavating projects around the house.

Simple to build in less than an hour, you need only a pair of scissors to make this fun and functional model. Great for kids 8 and up.

Become a "junior sleuth" by locating hidden finger impressions on door knobs, tables, glasses, telephones, automobiles, nearly anything! The Fingerprint Science kit lets you utilize real Police and FBI methods to gather prints of your family and friends. The classification cards let you store fingerprint information to help you locate your suspects! Includes a complete set of accessories plus a 16-page instruction manual.

Make 18 paper airplanes with cool designs and stickers. Includes 18 two-sided printed papers, stickers, folding tool, and easy instruction book packed in a printed storage folder.

Hopto it with Hoppers Jr., the Peg Solitaire Jumping Game. Help Red Frog Freddie win the Lily Pad Leaping Contest by being the last one in the pond. Each time a frog gets jumped, remove it from the board. You'll need to use smart moves to end up the winner!

40 Challenges, graded from Easy to Super Hard, have been specially designed to encourage children to explore, succeed, and have fun. Plus, the enclosed Parent's Guide offers tips to help your child enjoy an enriching play experience. Share the fun with Hoppers Jr. and watch your child's thinking skills and confidence grow - by leaps and bounds!

Everyone knows that sugar is bad for your teeth. But why is that so? Because Streptococcus mutans bacteria love to eat it!

S. mutans is the leading cause of tooth decay and a primary component of dental plaque. By eating sugars such as fructose (found in fruits), lactose (found in milk), and glucose (found in the starches of breads, pastas, cereals, and potatoes), S. mutans creates lactic acid that dissolves the minerals that make up your teeth. As these minerals dissolve, holes - or cavities - are created.

But like any sweet-tooth, S. mutans is most fond of the sugary sucrose found in cookies, cakes, candies, and soda! When sucrose is on the menu, S. mutans is able to produce not only acid, but also a sticky substance which helps it stay on your teeth - as plaque.

The more the plaque layer thickens and hardens, the more acid is produced and concentrated against your teeth, and the greater the risk of decay.

Because cavities are to a large extent a contagious disease (normally contracted by infants from family memberswhen their baby teeth come in), scientists are actively working on vaccines to help prevent infection.

But in the meantime, the best thing you can do to help your teeth stay healthy and strong is to brush and floss regularly - and avoid sugary foods.

They'll smile if you do!

West Nile virus is a mosquito-borne illness primarily found in Africa, West Asia, and the Middle East. It was first identified in Uganda in 1937 on the west side of the White Nile, one of the two tributaries of the Nile.

In recent years, the virus has been methodically spreading around the globe. But while West Nile outbreaks regularly attract a flood of media attention, about 80% of infected people experience no symptoms at all. Most of the rest experience flu-like symptoms, or West Nile fever, often accompanied by skin rashes on the chest and back.

However, in certain cases (less than 1%), West Nile virus penetrates the tissue in or around the brain and spinal cord, causing encephalitis and meningitis. In these rare instances, West Nile virus can cause paralysis, convulsions, coma, and even death.

While West Nile virus can infect many animals (its impact on horses is commonly cited), it most frequently afflicts birds - and the presence of dead birds in a community can be a harbinger of a West Nile virus outbreak. But mosquitoes are responsible for transmitting the virus from birds to humans, and as a result some communities institute mosquito control measures after warning signs appear. Reporting dead birds to public officials can help contain the threat posed by West Nile virus.

Nevertheless, it's wise to take extra precautions to avoid all mosquito bites during outbreaks - knowing which mosquitoes are infected is like solving the riddle of the sphinx.