the University of Pennsylvania
Researchers have devised a new method for aligning isolated single wall carbon nanotubes and, in the process, have created a new kind of material with liquid crystal-like properties, which they call nematic nanotube gels. The gels could potentially serve as sensors in complex fluids, where changes in local chemical environment, such as acidity or solvent quality, can lead to visible changes in the gel shape.
Coating DNA with a topical steroid might make for more effective therapeutic gene delivery, according to bioengineers at the University of Pennsylvania. The researchers have shown that a common anti-inflammatory steroid, wrapped around a strand of DNA, can prevent the immune responses commonly associated with gene-transfer techniques.
In a new report, scientists describe a technique that yields fertile primate sperm when tissue from the testes of young rhesus monkeys are grafted into mice. The research team believes that this method could be used to preserve genetic material from endangered nonhuman primates that might die before reproducing. They warn, however, that ethical and safety issues will need to be resolved before work on this method proceeds to the production of human sperm for assisted fertilization.
Becoming an adult takes longer today than in previous decades, with many not achieving all the traditional markers -- starting a career, forming a new household, starting a family -- until after age 30, according to a study by the Network on Transitions to Adulthood. According to the study, a demographic shift has occurred, almost without notice, but with important ramifications for the job market, the marriage market and public policy.
Babies are more vulnerable to serious head injury during a fall than had been previously thought, according to new research that may also begin to help child abuse investigators distinguish between accidental and intentional injury. Whitaker investigator Susan Margulies of the University of Pennsylvania found that rotational forces generated by a baby's head hitting a hard surface can cause widespread, potentially serious brain injury. This can include internal bleeding, which can damage tissue and alter brain function, and nerve cell damage, which can impair thinking, sensation, and other mental functions.
African Americans who gained weight rapidly in the first four months of life were more likely than their peers to be obese as young adults, 20 years later, according to researchers from The Children's Hospital of Philadelphia and the University of Pennsylvania. Their study, published in the June issue of the American Journal of Clinical Nutrition, analyzed data on 300 people in Philadelphia who were followed as part of a long-term, larger study from 1962 through 1989.
In a finding that could lay the groundwork for future cancer vaccines for children, cancer researchers working in cell culture have shown that modified immune cells can efficiently deliver genetic material to stimulate a desirable immune response.
Researchers from The Children's Hospital of Philadelphia and the Abramson Family Cancer Research Institute at the University of Pennsylvania manipulated immune cells called CD40-activated B cells to carry RNA produced by tumors and viruses. The RNA, which carries genetic codes from DNA, was obtained either from tumor or viral proteins. The researchers adapted an approach used in research on adults to one more appropriate for children.
Opening a new front in the battle against Alzheimer's disease, scientists at the University of Pennsylvania have found that a protein long associated with the disease inflicts grave damage in a previously unimagined way: It seals off mitochondria in affected neurons, resulting in an "energy crisis" and buildup of toxins that causes cells to die. This pathway, the first specific biochemical explanation for pathologies associated with Alzheimer's, is detailed in the April 14 issue of the Journal of Cell Biology.
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.
Researchers report that they have created tree-like molecules that assemble themselves into precisely structured building blocks of a quarter-million atoms. Such building blocks may be precursors to designing nanostructures for molecular electronics or photonics materials, which "steer" light in the same way computer chips steer electrons.
The largest-ever study of cocaine users who suffered heart-related effects from taking the drug finds that a specially designed plan of emergency-room care for such patients can save both lives and money. Such plans have been in place for traditional chest pain patients for years, and many hospitals set aside part of their ERs to hold them for observation. But doctors have lacked criteria to help them decide how long to hold patients whose chest pain was caused by cocaine - even as millions of Americans are using the drug.
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.
The presence of tumor-infiltrating lymphocytes predicts the length of remission after chemotherapy and the overall survival of patients with ovarian cancer, according to researchers from the Abramson Cancer Center and the Center on Women's Health at the University of Pennsylvania School of Medicine. Their findings, which are presented in the January 16th issue of the New England Journal of Medicine, constitute the first proof that a spontaneous immune response against the tumor dramatically impacts the clinical course of ovarian cancer. These novel findings generate hope that immune therapies may significantly prolong the response to chemotherapy and improve the survival of patients with advanced ovarian carcinoma.
At some point in fetal development, cells from the newly emerged blood circulatory system start out on their own and form a separate parallel network of vessels known as the lymphatic system. In the January 10th issue of Science, researchers report the discovery of the molecular signals necessary to separate the lymph vessel network from the blood vessel network. Their findings clarify an important juncture in fetal development, shed light on the mechanisms by which molecular signals influence vascular development, pave the way for potential therapeutics, and may ultimately clear up a minor mystery among researchers that has been brewing since the mid-1990s.
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."
