'Sleep debts' accrue when nightly sleep totals six hours or fewer

Those who believe they can function well on six or fewer hours of sleep every night may be accumulating a “sleep debt” that cuts into their normal cognitive abilities, according to research conducted at the University of Pennsylvania School of Medicine. What’s more, the research indicates, those people may be too sleep-deprived to know it. The study, published in the March 15 issue of the journal Sleep, found that chronically sleep-deprived individuals reported feeling “only slightly sleepy” even when their performance was at its worst during standard psychological testing. The results provide scientific insight into the daily challenges that confront military personnel, residents and on-call doctors and surgeons, shift workers, parents of young children, and others who routinely get fewer than six hours of sleep each night.

Surfactant curtails nanotube clumping in water, removing barrier to applications

Scientists have long touted carbon nanotubes as a futuristic means of delivering drugs, fortifying brittle materials and conducting current in miniaturized circuits. But attempts to introduce actual nanotubes into these roles have often been stopped in their tracks by the slender filaments’ stubborn and unhelpful tendency to clump together in solution. Now scientists at the University of Pennsylvania have found that a readily available chemical, a surfactant called sodium dodecylbenzene sulfonate (NaDDBS), disperses nanotubes in water with remarkable efficiency. The discovery, described in a paper published this month in the journal Nanoletters, represents an important step towards wider applications of nanotubes.

When self-image takes a blow, many turn to television as a distraction

Whether you fancy yourself a jet-setting sophisticate or a down-to-earth outdoorsy type, a fast-track corporate star or an all-around nice guy, new research indicates that you probably tune out information that challenges your self-image by tuning in to television. “We each have ways in which we like to perceive ourselves,” said one of the lead researchers. “In many cases self-image is carefully constructed and zealously guarded, and it’s difficult to experience a conflict between who we are and who we would like to be. Television appears to be an effective means of reducing awareness of how we are falling short of our own standards.”

Leukemia-Related Protein is a Master Editor of the ‘Histone Code’

Rearrangements of the mixed lineage leukemia gene, MLL, are associated with aggressive leukemias in both children and adults. Researchers at the University of Pennsylvania School of Medicine have found that one portion of the MLL protein is an enzyme that “edits” the so-called histone code, a series of modifications to proteins associated with DNA that influence how and when certain genes are turned on and off. Their findings are presented in the November issue of Molecular Cell.