Recent developments in Science & Technology

Brain: Life after death

Brain from a human dead body could yield life giving cells.New research raises the hope that cells, like organs, could one day be taken from the dead and given to the living. Fred Gage and his colleagues of the Salk Institute, have cultured neural progenitor cells- - which can go on to divide into nerve cells - from corpse brains. This could offer another, less ethically fraught alternative to fetal cells as a source of human replacement tissues.

The full medical potential of this finding is still unclear. The post-mortem cells do not divide as much as those from fetal tissue, for example, and the various types of cells they can form remain to be discovered.

These results confirm that the adult human brain contains cells that can continue to divide and differentiate, says Gage. For use in transplants, he says, this finding may eventually enable us to reactivate cells in the brains of living patients. This could lead to treatments for diseases such as Alzheimers and Parkinsons where nerve cells are lost.

Gage and his colleagues kept the cells functioning for many months; They can also be frozen for later use. Gage thinks progenitor cells for other tissues could probably be taken from people after death. But, he adds, the age of the donor and the time after death are important.

Source: Palmer, T. D. et al. Progenitor cells from human brain after
death. Nature 411, 42-43 (2001)

Scientists Explain Mysterious Quake

The devastating Assam earthquake of 1897 in north- eastern India has puzzled researches for more than a century. Now a team of scientists from the university of Colorado and the University of Oxford may have finally explained the event, which killed thousands of people and turned all masonry building in the region into rubble. Their findings also published in the April 2001issue of Nature an international science journal . Before this nobody really knew what happenedsays Rager Bilham of the University of Colorado.

Indian and the Eurasian tectonic plates collide in northern India, pushing up the Himalayas and earthquaks there are not uncomman. But the 1897 tremor was unusually large. To unravel the mystery, the team compared data from a century -old survey of India with several new computer models of geological faults. One earlier theory proposed that a rupture on the Himalayan thrust fault, which then propagated South of Bhutan to cause the quake. But the new analysis suggested that the primary fault- -the 78 mile- long Oldham fault-was beneath the Sillong plateau,some 100 miles south of Bhutan near Bangladesh.

According to the research team: The Indian plate was being pushed up against the Himalayas causing a portion of the land surface on the Shillong plateau to pop up like a segment of a peeled orange would pop up under pressure.Bilham explain We calculated the slip of the fault to be about 15 meter, one of the largest slips ever calculated for any earthquake. The thurst was so strong infact that boulders,tombstons and even people were tossed in the air he notes.

Fortunately an earthquake as powerful as the Assam event only occurs about once every 3000 years on the oldham fault say the scientists .They are very rare but could be extremely devastating in this region given the huge population of people now living in Bangladesh and poor construction practice there.

Scientific American News April 12,2001

Scientists Verify That Some Black Holes Spin

Scientists, who gathered for American Physical Society meeting in Washington recently verified that some blackholes spin. Tod Strohmayer of NASAs Goddard Space Flight Center presented concrete evidence that some black holes actually spin as they suck in their surroundings. Almost every kind of object in space spins, such as planets, stars and galaxies, he says. With black holes, its much harder to directly see that they are spinning, because they dont have a solid surface that you can watch spin around. But he proved his case nevertheless using data from NASAs Rossi X-ray Timing Explorer Satellite.

Strohmayer looked , a microquasar black hole about 10,000 light years from Earth. Jets of high-speed particles shot straight up and down from this type of black hole . And among the emanations, Strohmayer noticed two distinct patterns of flickeringX-rays known as quasiperiodic oscillations, or QPOs one previously detected QPO at 300 Hertz (Hz) and a new one at 450 Hz. Scientists had only ever detected this sort of radiation around spinning neutron stars.

The QPO at 450 Hz presented a puzzle. From it, Strohmayer calculated the innermost stable orbit-the closest anything can circle the black hole without falling in-should be 49 kilometers or less. And yet based on the black holes mass, estimated to be seven times greater than that of the Sun, the innermost stable orbit should be 64 kilometers. The only way to resolve the contradiction, Strohmayer says: A spinning black hole modifies the fabric of spacetime near it. The spinning allows matter to orbit at a closer distance than if it were not spinning. And the closer matter can get the faster it can orbit.

Source: Scientific American News, April 2001


Schizophrenia Linked to Viruses

According to a study published in journal of the National Academy of Sciences,viruses might trigger the disease Schizophrenia .These harbor retroviruses find in Schizophrenia patients in their cerebrospinal fluid and brain.More than two million Americans suffer from this disease, which typically mainfests itself in the age group of twenties.Researches believe the disease has both genetic and enviromental origin and some have suggested that retrovirus, which integrated their genetic materical into DNA, play a role.

To find out, scientists from the U.S. and Germany tested 35 newly diagnosed patients for retroviruses. They discovered that almost one third of these individuals contained genetic material from a certain class of retroviruses called HERV-W in their cerebrospinal fluid. In contrast, only 5 percent of chronic sufferers and none of the controls-a mix of patients with other neurological disorders and healthy people showed traces of the viruses. Whats more, the level of HERV-W virus was elevated in brains from dead schizophrenic patients, compared with healthy controls.

The scientists do not know if the retroviruses were endogenous, or naturally present in the genome and inherited, or if they entered the brain through infection. They also caution that some of the study groups were from geographically different areas, making them more difficult to compare. Furthermore, they are not sure by what mechanism HERV-W viruses may cause schizophrenia. Nerve cells making viral proteins may fuse (one HERV-W protein is known to cause cell fusion). In any case, retroviruses are likely to represent just one of several factors leading to schizophrenia.

Source:Scientific American News
Complied by : Kapil Tripathi