If you missed your morning coffee and now you have a headache and difficulty concentrating, you might be able to blame it on caffeine withdrawal. In general, the more caffeine consumed, the more severe withdrawal symptoms are likely to be, but as little as one standard cup of coffee a day can produce caffeine addiction, according to a Johns Hopkins study that reviewed over 170 years of caffeine withdrawal research.
Researchers at Purdue University and the Massachusetts Institute of Technology have completed a mathematical analysis showing that it isn’t quite possible to build a so-called ”perfect lens,” but the underlying theory still makes it feasible to design better imaging systems. A perfect lens would be able to focus light more narrowly than conventional lenses, making it possible to etch finer electronic circuits and create more compact and powerful computer chips. Such lenses also might lead to better fiberoptic communications systems and more precise medical imaging technologies.
Arsenic trioxide — a highly poisonous substance best known as an effective weed killer or pesticide and notorious for being a favourite ‘weapon’ of choice in murder mystery novels, is being re-invented as a treatment for a rare type of leukaemia. It is already licensed as an orphan drug (the term for drugs intended to treat rare conditions) for patients who have relapsed after initial therapy for acute promyeloctytic leukaemia (APL).
Neuroscientists at Duke University have figured out how to study with rigorous experimental control how the brain recalls autobiographical memories — the memories of a person’s past experiences. Their new ”photo paradigm” involves having subjects take photographs that they later recall in the laboratory while their brains are being scanned. The researchers said their study revealed that the brain uses much of the same machinery for both autobiographical memory and the type of memory elicited in previous laboratory studies. However, the new technique also disclosed significant brain function differences between laboratory memory and autobiographical memory.
In a nod to scientific paradox, researchers at the University of California, Berkeley, have slowed light down in an effort to speed up network communication. They have shown for the first time that the group velocity of light – the speed at which a laser pulse travels along a light wave – can be slowed to about 6 miles per second in semiconductors. While that speed is not exactly the pace of a turtle, it is 31,000 times slower than the 186,000 miles (or 300 million meters) per second that light normally clocks while traveling through a vacuum.
A common butterfly, found in a variety of habitats from the southern United States to northern Argentina, is actually comprised of at least 10 separate species, according to researchers from the University of Pennsylvania. Astraptes fulgerator, a medium-large skipper butterfly, is a routine visitor to urban gardens and tropical rainforests. While the ”species” has been known to science since 1775, only now has examination of a small and standardized signature piece of the genome — a technique called DNA barcoding — shown that this ”species” is really an amalgam of a number of genetically distinct lineages, each with different caterpillars and preferences in food plant and ecosystem. ”It raises the questions of how many other species out there are really multiple species like this one and what that might mean to wildlife conservation.”
Researchers have uncovered damage in a specific, primitive portion of the nervous systems of veterans suffering from Gulf War syndrome. Scientists report that damage to the parasympathetic nervous system may account for nearly half of the typical symptoms — including gallbladder disease, unrefreshing sleep, depression, joint pain, chronic diarrhea and sexual dysfunction — that afflict those with Gulf War syndrome. Their findings will be published in the October issue of the American Journal of Medicine and are currently available online.
Among men without heart disease but who have significant cardiac risk factors, a poor performance on an exercise treadmill test is associated with more than doubling of the risk for a heart attack or other coronary heart disease event, according to a new report. Exercise treadmill testing is not generally recommended as routine screening for people with no history or symptoms of heart disease. This is the first study to evaluate exercise testing among asymptomatic people relative to their predicted coronary heart disease (CHD) risk using the Framingham risk score.
A new study headed by biologists at Washington University in St. Louis shows that Florida is an exporter of more than just fruit and star athletes. Studying genetic variation in the common brown lizard, Anolis sagrei, the researchers found that introduced populations of the lizard in five different countries can be traced back to the Sunshine State as their site of export. The team analyzed a small region of DNA from more than 600 different individuals to get a genetic ”ID card” for each lizard. The historic home for Anolis sagrei is the Caribbean, especially Cuba, where the researchers have found that there are at least eight genetically distinct groups of the lizard.
When it comes to affairs of the heart, love taps are preferred over love jolts. That is the result of a team of heart researchers including Igor Efimov, Ph.D., associate professor of biomedical engineering at Washington University in St. Louis, trying to effect a better implantable heart defibrillator. Efimov and his colleagues have modeled a system where an implantable heart defibrillator focuses in on rogue electrical waves created during heart arrhythmia and busts up the disturbance, dissipating it and preventing cardiac arrest.
Marijuana use may increase the risk of ectopic (tubal) pregnancies, researchers at Vanderbilt University Medical Center reported this week. The researchers studied CB1, a ”cannabinoid” receptor that binds the main active chemical for marijuana, delta-9-tetrahydrocannabinol (THC). In pregnant mice that lacked the gene for the receptor, or in which the receptor was blocked, the embryo failed to go through the oviduct — the tube leading from the ovaries to the uterus. The same thing happened in normal mice when the receptor was over-stimulated.
Although black men in the United States are more likely than white men to be diagnosed with advanced prostate cancer and have a two-fold greater risk of dying from it, they are significantly less likely to be screened for prostate cancer, according to a Dana-Farber Cancer Institute and Brigham and Women’s Hospital study. In a study involving more than 67,000 men age 65 years and older, the researchers found that blacks were 35 percent less likely than whites to undergo prostate-specific antigen (PSA) testing.
Vietnam veterans had higher death rates in the first five years after discharge than veterans who did not serve in Vietnam, according to a new 30-year follow-up study. During the 1980s, the Centers for Disease Control and Prevention conducted the Vietnam Experience Study (VES) to look at the long-term health effects of military service in Vietnam. Serving in Vietnam exposed servicemen to several possible health factors, including exposure to psychological stress associated with war, infectious diseases prevalent in Vietnam, pesticides and herbicides, and drug and alcohol abuse. The original VES followed 18,313 US Army veterans from their date of discharge from active duty (1965-1977) through December 31, 1983. This study was somewhat limited by the young age of the participants (average age, 36.1 years) and the small number of deaths (446), the article states.
Astronomers have used an X-ray image to make the first detailed study of the behavior of high-energy particles around a fast moving pulsar. The image, from NASA’s Chandra X-ray Observatory, shows the shock wave created as a pulsar plows supersonically through interstellar space. These results will provide insight into theories for the production of powerful winds of matter and antimatter by pulsars.