When human heart muscle cells derived from embryonic stem cells are implanted into a rat after a heart attack, they can help rebuild the animal's heart muscle and improve function of the organ, scientists report. The researchers also developed a new process that greatly improves how stem cells are turned into heart muscle cells and then survive after being implanted in the damaged rat heart.

Forget about magnets on your fridge -- researchers are trying to make magnetic fields do the work of your fridge. The first milestone of between 5 and 10 Celsius degrees in magnetic cooling has now been achieved. The figure is currently at 8.7C -- this means that a refrigerator at room temperature (20C) can be cooled to almost 11C. Of course, this is not quite enough to keep the milk cold, but the project's test setup also has only the one objective of conducting research in different materials, varying operating conditions and the strength of the magnetic field. This could one day offer a quiet and green alternative to current refrigerators.

Analysis of the chemical make up of two asteroids in the outer asteroid belt has thrown the classification system for these small bodies, which orbit between Mars and Jupiter, into disorder. The presence of basalt means that the asteroid must have melted partially at some time in the past, which implies that it was once part of a larger body which had internal heating processes. However, there do not appear to be other basaltic fragments in the region and, from spectral analysis, it is not clear whether the two are fragments of the same parent body or not.

The female sex hormone estrogen turns on a gene linked to breast cancer, according to new research. The scientists believe their finding will help explain the link between breast cancer and high levels of estrogen.

Blockbuster will rent high-definition DVDs only in the Blu-ray format in 1,450 stores, dealing a major blow to the rival HD DVD format.