成都大隐静脉曲张治疗价钱成都治疗下肢动脉硬化那便宜,成都专治老烂腿的医院,成都脉管炎怎样治疗好呢,成都脉管畸形医院,成都小腿血管炎专治医院,成都哪里治疗雷诺氏病好,成都肝血管瘤哪里做手术比较好

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. 21 (Xinhua) -- NASA's Dawn spacecraft has sent around 10,000 pictures of the giant asteroid Vesta back to Earth for the first time since its launch in 2007, the U.S. space agency announced Wednesday.The images were taken from an average altitude of 209 km, the closest the spacecraft can get.From the images, scientists could see Vesta's stippled and lumpy surface in great detail, and its many small craters, grooves, and lineaments. The fine scale of the images highlights small outcrops of bright and dark material.With these new discoveries, scientists believe that studying Vesta can help decode the early history of the solar system.Dawn will maintain its low-altitude orbit for another 10 weeks before moving to a higher orbit for another round of photo-taking.Launched in 2007, the 446 million U.S. dollar project aims at studying the chemical composition of Vesta's surface and probing its interior structure.Dawn will leave Vesta in July next year and arrive at the dwarf planet Ceres in February 2015.

SAN FRANCISCO, Nov. 21 (Xinhua) -- E-commerce and online payment giant eBay announced on Monday that it has acquired New York-based technology startup Hunch, an online platform that delivers customized recommendations to users based on their individual tastes.Hunch's team and expertise in areas like machine learning, data mining and predictive modeling are expected to help eBay to integrate more advanced recommendations into its website, said the San Jose, California-based company."Unlike traditional online retail approaches, Hunch will enable eBay to move beyond standard item-to-item recommendations and use a broader variety of members' online tastes and interests to suggest new and interesting items for them to browse and buy on eBay," said the company in a press release.Terms of the deal were not disclosed. Technology news site TechCrunch founder Michael Arrington said in his personal blog prior to the acquisition announcement that eBay would acquire Hunch for 80 million U.S. dollars.Hunch, co-founded by popular photo-sharing service Flickr co- founder Caterina Fake with an 11-person team of MIT graduates, was open to the public in 2009. According to eBay, Hunch's employees will remain with the company in New York.