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BEIJING, Oct. 26 (Xinhuanet) -- The question, why the first documented supernova was super-sized and grew so fast, has puzzled astronomers for centuries. Now it is solved by US researchers.The supernova, an exploded star, was observed in 185 A.D. and documented as a mysterious "guest star" by Chinese astronomers. It was visible for eight months.Scientists later found the supernova, 8,000 light years away, was a bigger-than-expected supernova remnant. BBC reported that if the infrared light it emits could be seen by human eyes, it would appear to be as large as the full Moon in the sky.Through observations in space telescopes, researchers of a latest study revealed that the explosion took place in a cavity in space, which allowed the star's remains to travel out much faster and farther. The study was published online in the Astrophysical Journal Monday.The supernova was "two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we've been able to finally pinpoint the cause," stated Brian Williams, lead author of the study and an astronomer at North Carolina State University in Raleigh.

WASHINGTON, Dec. 7 (Xinhua) -- Drugs that affect the levels of an important brain protein involved in learning and memory reverse cellular changes in the brain seen during aging, according to an animal study published Wednesday in the Journal of Neuroscience. The findings could one day aid in the development of new drugs that enhance cognitive function in older adults.Aging-related memory loss is associated with the gradual deterioration of the structure and function of synapses (the connections between brain cells) in brain regions critical to learning and memory, such as the hippocampus.Recent studies suggested that histone acetylation, a chemical process that controls whether genes are turned on, affects this process. Specifically, it affects brain cells' ability to alter the strength and structure of their connections for information storage, a process known as synaptic plasticity, which is a cellular signature of memory.In the current study, Cui-Wei Xie, of the University of California, Los Angeles, and colleagues found that compared with younger rats, hippocampi from older rats have less brain-derived neurotrophic factor (BDNF) -- a protein that promotes synaptic plasticity -- and less histone acetylation of the Bdnf gene. By treating the hippocampal tissue from older animals with a drug that increased histone acetylation, they were able to restore BDNF production and synaptic plasticity to levels found in younger animals."These findings shed light on why synapses become less efficient and more vulnerable to impairment during aging," said Xie, who led the study. "Such knowledge could help develop new drugs for cognitive aging and aging-related neurodegenerative diseases, such as Alzheimer's disease," she added.

WASHINGTON, Dec. 12 (Xinhua) -- British scientists have discovered a new way to target cancer through manipulating a master switch responsible for cancer cell growth. The findings, published Monday in the U.S. journal Cancer Cell, reveal how cancer cells grow faster by producing their own blood vessels.Cancer cells gain the nutrients they need by producing proteins that make blood vessels grow, helping deliver oxygen and sugars to the tumor. These proteins are vascular growth factors like VEGF -- the target for the anti-cancer drug Avastin. Making these proteins requires the slotting together of different parts of genes, a process called splicing.Scientists at the University of West England and the University of Bristol discovered that mutations in one specific cancer gene can control how splicing is balanced, allowing a master switch in the cell to be turned on. This master switch of splicing makes cancer cells grow faster, and blood vessels to grow more quickly, as they alter how VEGFs are put together.In experimental models, the researchers found that by using new drugs that block this master switch they prevented blood vessel growth and stopped the growth of cancers."The research clearly demonstrates that it may be possible to block tumor growth by targeting and manipulating alternative splicing in patients, adding to the increasingly wide armory of potential anti-cancer therapies," the authors said.

BEIJING, Jan. 4 (Xinhua) -- Senior Chinese leader Li Changchun on Wednesday called for more efforts to strengthen the Internet construction and management and promote a healthy online culture.Li, a member of the Standing Committee of the Political Bureau of the Communist Party of China Central Committee, made the remarks at a national conference of publicity officials.Li also urged the officials to work and fortify the leading status of Marxism in the country's ideological field, and to provide spiritual support for the economic and social development.Li Changchun (C), a member of the Standing Committee of the Political Bureau of the Communist Party of China Central Committee, addresses a national conference of publicity officials in Beijing, capital of China, Jan. 4, 2012.The publicity work should help create a favorable environment for the country's efforts to stabilize economic growth, regulate commodity prices, adjust the economic structure, improve people's livelihood, carry forward reform and promote social harmony, Li said.Moreover, Li called for efforts to deepen the reform and promote development in the country's cultural sector.

来源：资阳报