People with medium levels of HIV in their blood are likely to contribute most to the spread of the virus, according to new research published today in the journal Proceedings of the National Academy of Sciences.

The study, by researchers from Imperial College London, looked at several groups of HIV-positive people in Europe, the USA and sub-Saharan Africa. It found that those with a high viral load are the most infectious group, but have only limited time to infect others, because they generally progress to AIDS quite quickly.

Viral load - a count of how many viral particles are in a person’s blood – varies hugely between individuals. The higher the viral load, the more infectious a person is but the shorter their life expectancy.

“Being a coral reef scientist these days can be depressing. So many reefs around the world have collapsed before our eyes in the past few years,” says Professor Terry Hughes, Director of the ARC’s Centre of Excellence for Coral Reef Studies. “But we’ve got to get past the gloom-and-doom, and use the best science to find practical ways to protect reefs from global warming.”

The world has a narrow window of opportunity to save coral reefs from the destruction caused by extreme climate change, according to a unanimous statement issued today by leading Australian scientists (see communiqué, above). The call for action is the outcome of a National Forum on Coral Reef Futures, held at the Australian Academy of Science, in Canberra.

Without sleep, the emotional centers of the brain dramatically overreact to negative experiences, reveals a new brain imaging study in Current Biology.   The reason for that hyperactive emotional response in sleep-deprived people stems from a shutdown of the prefrontal lobe—a region that normally keeps emotions under control.

The new study from Harvard Medical School and the University of California, Berkeley is the first to explain, at the neural level, what seems to be a universal phenomenon: that sleep loss leads to emotionally irrational behavior, according to the researchers. The findings might also offer some insight into the clinical connection between sleep disruptions and psychiatric disorders.

Philosophers and scientists have long been interested in how the mind processes the inevitability of death, both cognitively and emotionally. One would expect, for example, that reminders of our mortality - like the sudden death of a loved one - would throw us into a state of disabling fear of the unknown. But that doesn't happen. If the prospect of death is so incomprehensible, why are we not trembling in a constant state of terror over this fact?

Psychologists have some ideas about how we cope with existential dread. One emerging idea--"terror management theory" --holds that the brain is hard-wired to keep us from being paralyzed by fear.

Researchers at Tufts University School of Medicine in collaboration with the Virginia Bioinformatics Institute at Virginia Tech have created a computer program called Pathogen Simulation (PathSim) to study the progression of Epstein-Barr virus (EBV) in humans. David Thorley-Lawson, PhD, professor of pathology at Tufts University School of Medicine, is combining PathSim, laboratory methods, and clinical studies to provide a new and powerful approach to understanding EBV and ultimately designing anti-viral therapies.

“PathSim is an agent-based computer program. The agents are the virus itself, and the T and B cells of the patient’s immune system,” explains Thorley-Lawson. Using PathSim, Thorley-Lawson can manipulate these agents to simulate EBV infection and persistence in humans.

With an eye on curing diabetes, scientists at Washington University School of Medicine in St. Louis have successfully transplanted embryonic pig pancreatic cells destined to produce insulin into diabetic macaque monkeys – all without the need for risky immune suppression drugs that prevent rejection.

The transplanted cells, known as primordia, are in the earliest stages of developing into pancreatic tissues. Within several weeks of the transplants, the cells became engrafted, or established, within the three rhesus macaque monkeys that received them. The cells also released pig insulin in response to rising blood glucose levels, as would be expected in healthy animals and humans.

A clinical trial evaluating a brain cancer vaccine in patients with newly diagnosed brain cancer has begun at NYU Medical Center. The study will evaluate the addition of the vaccine following standard therapy with surgery and chemotherapy in patients with glioblastoma multiforme, a deadly form of brain cancer.

The vaccine, called DCVax-Brain, incorporates proteins found in patients’ tumors and is designed to attack cancer cells containing these proteins. The study underway at NYU Medical Center is an expansion of an earlier phase I trial of the vaccine. The vaccine is made by the Northwest Biotherapeutics, Inc., based in Bothell, Washington.

“We are really excited about the promise of this vaccine,” said Patrick J.

Sandia National Laboratories’ Z machine, the world’s largest producer of X-rays, shook the ground for several hundred yards in every direction for the first time since July 2006, when the 22-year-old facility was gutted to undergo a complete refurbishment at a total project cost of $90 million.

Z has been overbooked in recent years with requests for experiment time from national labs, universities, and the international community. The facility is in demand because of Z’s capability to subject materials to immense pressures, compress spherical capsules to produce thermonuclear fusion reactions, fire objects much faster than a rifle bullet, and produce data for models of nuclear weapons effects — as well as, more arcanely, the conditions surrounding black holes in space.

From absorbable sutures to gel-like cold-and-flu capsules, polymers have been used for years in the human body to help heal what ails us.

Today, scientists are pioneering the development of new “polymer drugs”--long-chained molecules that have therapeutic benefits because of their chemical composition and high molecular weight. The potential benefits of these novel drugs range from the more precise targeting of cancer-fighting chemotherapy treatments, to the sequestering and removal of toxins in the body.

Kristi Kiick, associate professor of materials science and engineering at the University of Delaware, recently published an article on polymer therapeutics in the prestigious journal Science.