In its early and most critical stages, human reproduction requires precise, vital functions. The role of one sperm-delivered protein, which is crucial to the process, is being closely observed by scientists from the United States and Canada.

In 2002, when astronomers first detected cosmic gamma rays – the most energetic form of light known – coming from the constellation Cygnus they were surprised and perplexed. The region lacked the extreme electromagnetic fields that they thought were required to produce such energetic rays. But now a team of theoretical physicists propose a mechanism that can explain this mystery and may also help account for another type of cosmic ray, the high-energy nuclei that rain down on Earth in the billions.

A newly discovered small molecule called IQ-1 plays a key role in preventing embryonic stem cells from differentiating into one or more specific cell types, allowing them to instead continue growing and dividing indefinitely, according to research performed by a team of scientists who have recently joined the stem-cell research efforts at the Keck School of Medicine of the University of Southern California.

Exposing teeth to soft drinks, even for a short period of time, causes dental erosion—and prolonged exposure can lead to significant enamel loss. Root beer products, however, are non-carbonated and do not contain the acids that harm teeth, according to a study in the March/April 2007 issue of General Dentistry, the AGD's clinical, peer-reviewed journal. That might be something to consider during the next visit to the grocery store.

Consumers often consider soft drinks to be harmless, believing that the only concern is sugar content. Most choose to consume "diet" drinks to alleviate this concern. However, diet drinks contain phosphoric acid and/or citric acid and still cause dental erosion—though considerably less than their sugared counterparts.

A group of organisms that has never had sex in over 40 million years of existence has nevertheless managed to evolve into distinct species, says new research published today. The study challenges the assumption that sex is necessary for organisms to diversify and provides scientists with new insight into why species evolve in the first place.

The research, published in PLoS Biology, focuses on the study of bdelloid rotifers, microscopic aquatic animals that live in watery or occasionally wet habitats including ponds, rivers, soils, and on mosses and lichens. These tiny asexual creatures multiply by producing eggs that are genetic clones of the mother – there are no males.

Disrupt the gene that regulates the biological clocks in mice and they become manic, exhibiting behaviors similar to humans with bipolar disorder, UT Southwestern Medical Center researchers have found.

In a study available online in the Proceedings of the National Academy of Sciences, scientists from UT Southwestern show that the Clock gene, which controls the body's circadian rhythms, may be integrally involved in the development of bipolar disorder. Circadian rhythms include the daily ups-and-downs of waking, eating and other processes such as body temperature, hormone levels, blood pressure and heart activity.