STANFORD, Calif. - Researchers at the Stanford University School of Medicine have taken a small but significant step, in mouse studies, toward the goal of transplanting adult stem cells to create a new immune system for people with autoimmune or genetic blood diseases.

The researchers found a way to transplant new blood-forming stem cells into the bone marrow of mice, effectively replacing their immune systems. Many aspects of the technique would need to be adapted before it can be tested in humans, said Irving Weissman, MD, a co-senior author of the study and director of the Stanford Institute for Stem Cell Biology and Regenerative Medicine. The work was done on a particular group of mice that are a poor mimic for the human immune system.

Brain scanning experiment shows how much we take others' earnings as a measure of our success.

The feelings an individual has on receiving his paycheque depend critically on how much his colleague earns. Hard evidence for this comes from an experiment conducted by economists and brain scientists at the University of Bonn. They tested male subjects in pairs, asking them to perform a simple task and promising payment for success. Using magnetic resonance tomographs, the researchers examined the volunteers' brain activity throughout the activities. Participants who got more money than their co-players showed much stronger activation in the brain's "reward centre" than occurred when both players received the same amount.

MIT researchers have found that the children of mothers whose water supplies were contaminated with arsenic during their pregnancies harbored gene expression changes that may lead to cancer and other diseases later in life.

In addition to establishing the potential harmful effects of these prenatal exposures, the new study also provides a possible method for screening populations to detect signs of arsenic contamination.

This is the first time evidence of such genome-wide changes resulting from prenatal exposure has ever been documented from an environmental contaminant. It suggests that even when water supplies are cleaned up and the children do not experience any direct exposure to the pollutant, they may still suffer lasting damage.

It was not the isolation of the Ice Age that determined the genetic distribution of bears, as has long been thought, according to an international research team writing in the latest issue of Molecular Ecology. One possible interpretation is that the hunting of bears by humans and human land use have been crucial factors.

Twenty thousand years ago Europe was covered by ice down to Germany, and the climate in the rest of Europe was such that several species were confined to the southern regions, like the Iberian Peninsula and Italy.

These regions were refuges, areas where species could survive during cold periods and then re-colonize central and northern Europe when it got warmer.

Newly launched nerve cells in a growing embryo must chart their course to distant destinations, and many of the means they use to navigate have yet to surface. In a study published in the current issue of the journal Neuron, scientists at the Salk Institute for Biological Studies have recovered a key signal that guides motor neurons – the nascent cells that extend from the spinal cord and must find their way down the length of limbs such as arms, wings and legs.

The Salk study, led by Samuel Pfaff, Ph.D, a professor in the Gene Expression Laboratory, identifies a mutation they christened Magellan, after the Portuguese mariner whose ship Victoria was first to circumnavigate the globe.

Writing in Atoms for Peace, Energy consultant David Wood suggests that Iran's demands for nuclear power in economic and technical terms are a justified response to rapid growth in domestic energy demands and an increased dependence on oil exports for revenue.

Despite its vast oil and gas reserves, years of under-investment in Iran has limited access to technology and stifled its production capacity. Indeed, Iran now relies on imports for certain refined petroleum products and natural gas. Wood argues that the development of this situation has forced Iran to consider alternative future energy solutions.