Our body’s 24-hour internal clock, or circadian clock, regulates the time we go to sleep, wake up and become hungry as well as the daily rhythms of many metabolic functions. The clock – an ancient molecular machine found in organisms large and small, simple and complex – properly aligns one’s physiology with one’s environment. Now, for the first time, a Northwestern University and Evanston Northwestern Healthcare (ENH) study has shown that overeating alters the core mechanism of the body clock, throwing off the timing of internal signals, including appetite control, critical for good health. Animals on a high-fat diet gained weight and suddenly exhibited a disruption in their circadian clocks, eating extra calories during the time they should have been asleep or at rest. The study, which will be published in the Nov. 7 issue of the journal Cell Metabolism, also shows that changes in metabolic state associated with obesity and diabetes not only affects the circadian rhythms of behavior but also of physiology. Probing beyond the behavioral level, the researchers observed actual changes in genes that encode the clock in the brain and in peripheral tissues (such as fat), resulting in diminished expression of those genes.

Research has shown convincing evidence that dietary patterns practiced during adulthood are important contributors to age-related cognitive decline and dementia risk. An article published in Annals of the New York Academy of Sciences highlights information on the benefits of diets high in fruit, vegetables, cereals and fish and low in saturated fats in reducing dementia risk. Adults with diabetes are especially sensitive to the foods they eat with respect to cognitive function. Specifically, an adult with diabetes will experience a decline in memory function after a meal, especially if simple carbohydrate foods are consumed. While the precise physiological mechanisms underlying these dietary influences are not completely understood, the modulation of brain insulin levels likely contributes.

Catastrophic bridge collapses in Minnesota, China and elsewhere have killed at least 58 people this year, and concrete weakened by water is partly to blame. A new study points to a waterproofing solution that lies close at hand—or, er, mouth: sodium acetate, the ingredient that gives salt-and-vinegar chips their delicious zing. Water seeps through concrete’s pores, cracking its exterior and damaging the steel beams within. Sodium acetate seals these pores from the inside, says researcher Awni Al-Otoom of the Jordan University of Science and Technology in Irbid, Jordan. When brushed onto concrete as part of a watery solution, the salty substance sinks in and forms crystals, partially plugging the pores. The crystals create an even better barrier when wet, since moisture—a drop of rain, say—makes them swell to fill openings more snugly.

A Michigan couple celebrated their first wedding anniversary and, more importantly being alive, after the minivan they were in was struck by a falling object … a 600-pound cow. Charles and Linda Everson were driving back to their hotel in Manson, Wash., where they were visiting, when the year-old cow fell 200 feet off a cliff and onto the hood of their vehicle. They missed being killed by a matter of inches, authorities said.

A previously undiscovered type of aurora could be brightening the skies over the poles. That’s the conclusion from satellite images of the poles showing the new phenomenon above Antarctic in 2004. The conventional aurora borealis in the Arctic and aurora australis in the Antarctic are typically seen as curtains of brightly coloured light descending through the atmosphere near the poles. The light is generated when electrons from the solar wind become trapped and accelerated by the Earth’s magnetic field to energies in excess of 1 kiloelectronvolt.

A new theory developed at MIT could lead to “smart” optical microchips that adapt to different wavelengths of light, potentially advancing telecommunications, spectroscopy and remote sensing. Drawn by the promise of superior system performance, researchers have been exploring the concept of microchips that manipulate light instead of electricity. In their new theory, the MIT team has shown how such chips could feature tiny machines with moving parts powered and controlled by the very light they manipulate, giving rise to fundamentally new functionality. “There are thousands of complex functions we could make happen by tinkering with this idea,” said Peter Rakich, an MIT postdoctoral associate who invented the theoretical concept along with postdoc Milos Popovic. The work was described in the cover story of the November issue of Nature Photonics. For example, such chips could one day be used to remotely adjust the amount of bandwidth available in an optical network, or to automatically process signals flowing through fiber-optic networks, without using any electrical power, Rakich said.

Forgers take heed, a simple way to detect fake bank notes using their inks’ unique “magnetic signature” can also be used to authenticate oil paintings, according to the scientists who invented the technique. Some of the inks used to print bank notes around the world are made of ferrofluids, which are magnetic. These generate weak magnetic fields that can be measured using instruments such as superconducting quantum interference devices (SQUIDs). A SQUID can be simply scanned across the note to record a “map” of its magnetic flux. Previously, Paulo Costa Ribeiro of the Pontifical Catholic University of Rio de Janeiro in Brazil and colleagues made magnetic maps of Brazilian bank notes and found that each note has a unique signature that remains stable over time.

They have cracked the genetic code of humans, cats, dogs and chimps. Now, scientists reveal today they have solved the secrets of dandruff. A team of researchers has decoded the complete DNA of a natural fungus to blame for most cases of the flaky skin condition. The findings could lead to more effective shampoos, lotions and medicines for a problem affecting more than half the population. Dr Thomas Dawson, who led the five-year study, said: “We have been able to see how the fungus interacts with the skin, and that opens up all sorts of new targets for medication.” Almost all cases are linked to Malassezia globosa, a yeast that lives on human skin. The fungus feeds off natural oils in the skin and releases a toxic by-product that can irritate the scalp, causing itchiness and clumps of dead skin that are noticeable on hair and clothes.

Breastfed babies are less likely to have certain cardiovascular disease (CVD) risk factors in adulthood than their bottle-fed counterparts, researchers reported at the American Heart Association’s Scientific Sessions 2007. “Having been breastfed in infancy is associated with a lower average body mass index (BMI) and a higher average HDL (high-density lipoprotein or “good” cholesterol) level in adulthood, even after accounting for personal and maternal demographic and CVD risk factors that could influence the results,” said Nisha I. Parikh, M.D., M.P.H., author of the study and a cardiovascular fellow at the Beth Israel Deaconess Medical Center in Boston, Mass. A lower BMI and high HDL both protect against CVD. The study, which used data from two generations of participants in the Framingham Heart Study, showed that middle-aged adults who were breastfed as infants were 55 percent more likely to have high HDL cholesterol than to have low HDL cholesterol. Low HDL was defined as levels of less than 50 mg/dL for women and less than 40 mg/dL for men. HDL is known as “good” cholesterol because high levels help protect against heart disease and stroke.

Our increasingly interconnected world has made it easier for information and disease to spread. However a new study from Harvard University and Cornell University shows that fewer “degrees of separation” can make social networks too weak to disseminate behavioral change. The finding that “small world” networks are limited in their power to shape individual behavior could have implications for health care policy and the treatment of epidemics. Published in the November American Journal of Sociology, the study was led by Damon Centola, a Robert Wood Johnson Fellow with the Institute for Quantitative Social Science in Harvard’s Faculty of Arts and Sciences, with Michael Macy of Cornell. The work was done while Centola was a doctoral candidate at Cornell. “Our research shows that the difference between contagions that spread through simple contact, such as diseases and information, and the spread of behavior, which requires multiple contacts, has important consequences,” says Centola. “We find that while making the world smaller increases the speed at which diseases and information can spread, it can actually slow down, and even prevent, the spread of health behaviors.”

Don’t slack off on exercise if you want to avoid packing on the pounds as you age. A consistently high level of physical activity from young adulthood into middle age increases the odds of maintaining a stable weight and lessens the amount of weight gained over time, according to a new analysis from Northwestern University’s Feinberg School of Medicine. People who reported at least 30 minutes of vigorous activity a day such as jogging, bicycling or swimming were more than twice as likely to maintain a stable Body Mass Index (BMI) over 20 years. BMI is a measure of body fat based on height and weight. But even highly active people who gained weight, gained 14 pounds less over 20 years than those with consistently low activity. Although activity is often recommended as a way to prevent weight gain, this is one of the first studies to examine the relationship between activity and weight by looking at patterns of exercise over a long period of time.

Newly created neurons in adults rely on signals from distant brain regions to regulate their maturation and survival before they can communicate with existing neighboring cells–a finding that has important implications for the use of adult neural stem cells to replace brain cells lost by trauma or neurodegeneration, Yale School of Medicine researchers report in The Journal of Neuroscience. In fact, certain important synaptic connections–the circuitry that allows the brain cells to talk to each other–do not appear until 21 days after the birth of the new cells, according to Charles Greer, professor of neurosurgery and neurobiology, and senior author of the study, In the meantime, other areas of the brain provide information to the new cells, preventing them from disturbing ongoing functions until the cells are mature.

Missing something? The vents on the space shuttle and International Space Station serve as the lost and found, sucking up anything that’s floating about unsecured. The shuttle commode requires that astronauts align themselves precisely in the dead center of the seat. A mock-up of the shuttle toilet, complete with built-in camera, is used to train them how to position themselves, and more…

After clocks are turned back this weekend, pedestrians walking during the evening rush hour are nearly three times more likely to be struck and killed by cars than before the time change, two U.S. scientists calculate. Ending daylight saving time translates into about 37 more U.S. pedestrian deaths around 6 p.m. in November compared to October, the researchers report. Their study of risk to pedestrians is preliminary but confirms previous findings of higher deaths after clocks are set back in fall. It’s not the darkness itself, but the adjustment to earlier night time that’s the killer, said professors Paul Fischbeck and David Gerard, both of Carnegie Mellon University in Pittsburgh.