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Stopping In Thin Air

Imagine you're going very fast -- much faster than a race car. In fact, imagine you're going 100 or 200 times faster than a race car. When you reach your destination, you need to stop relatively quickly. How would you do it? It wouldn't take a rocket scientist to think of using the brakes. But, it might take a rocket scientist to skip the brakes, ...

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StoppingInThinAir
Geology

A National Park of Caves

Carlsbad Caverns National Park has been designated as a world heritage site because of its unique and surprising geology - a story more than 250 million years old that can be read both above and below ... Continue reading

ANationalParkofCaves
Chemistry

Uses Of Hydrocarbons

The hydrocarbons are the most broadly used organic compounds known, and are quite literally the driving force of western civilization. The greatest amounts of hydrocarbons are used as fuel for ... Continue reading

UsesOfHydrocarbons
Biology

Microarrays: Chipping Away At The Mysteries Of Science And Medicine

With only a few exceptions, every cell of the body contains a full set of chromosomes and identical genes. Only a fraction of these genes are turned on, however, and it is the subset that is ... Continue reading

Microarrays
Geology

Heading For The Badlands

The bizarre landforms called badlands are, despite the uninviting name, a masterpiece of water and wind sculpture. They are near deserts of a special kind, where rain is infrequent, the bare rocks are ... Continue reading

HeadingForTheBadlands

St. John's Wort

StJohnsWortSt. John's wort is an herb that has been used for centuries for medicinal purposes, including to treat depression. The composition of St. John's wort and how it might work are not well understood. There is some scientific evidence that St. John's wort is useful for treating mild to moderate depression. However, recent studies suggest that St. John's wort is of no benefit in treating major depression of moderate severity. More research is required to help us know whether St. John's wort has value in treating other forms of depression. St. John's wort interacts with certain drugs, and these interactions can be dangerous. Herbal products vary greatly as to their chemical composition and quality.

St. John's wort (Hypericum perforatum in Latin) is a long-living plant with yellow flowers. It contains many chemical compounds. Some are believed to be the active ingredients that produce the herb's effects, including the compounds hypericin and hyperforin. How these compounds actually work in the body is not yet known, but several theories have been suggested. Preliminary studies suggest that St. John's wort might work by preventing nerve cells in the brain from reabsorbing the chemical messenger serotonin, or by reducing levels of a protein involved in the body's immune system functioning.

St. John's wort has been used for centuries to treat mental disorders as well as nerve pain. In ancient times, doctors and herbalists (specialists in herbs) wrote about its use as a sedative and treatment for malaria as well as a balm for wounds, burns, and insect bites. Today, St. John's wort is used by some people to treat mild to moderate depression, anxiety, or sleep disorders. Herbal products such as St. John's wort are classified as dietary supplements by the U.S. Food and Drug Administration (FDA), a regulatory agency of the Federal Government. The FDA's requirements for testing and obtaining approval to sell dietary supplements are less strict than its requirements for drugs. Unlike drugs, herbal products can be sold without requiring studies on dosage, safety, or effectiveness.