Basic Science

1.1 MW Ion Beam Extracted on EAST-NBI Ion Source

The hydrogen ion beam with 1.1 MW beam power was extracted on the EAST neutral beam injector (EAST-NBI) ion source during its staged test in the Institute of Plasma Physics, CAS (ASIPP), a milestone in the development of high current ion source. During the test, 22A beam current with 50keV beam energy and 106ms pulse length was achieved; the ion beam power reaches 1.1 MW. Test results demonstrates that the EAST-NBI project has achieved on schedule its milestone objective – development of the first mega-watt high current ion source and high power NBI experimental equipment. In half a year since approval of EAST auxiliary heating system project in July, 2010, EAST NBI group has worked day and night on discharge test, aging test and joint debugging of sub-systems on the test bed. After stable and repeatable 100-second long pulse arc discharges were achieved, the hydrogen ion beam with 1.1 MW beam power was successfully extracted thirty days later. According to the analysis of data obtained from the calorimeter, vertical and horizontal beam divergence angle are 0.72 and 0.92 respectively and the distribution of beam power density obeys Gaussian distribution. This shows that EAST-NBI ion source has preliminarily reached the design technical parameters.

Acetyltransferase Patt1 Plays Important Role in Hepatic Lipid Metabolism

Nonalcoholic fatty liver disease (NAFLD), one of the most common causes of chronic liver disease including cirrhosis, hepatocellular carcinoma and liver failure, is recognized increasingly as a major health burden. Hepatic steatosis is an early stage of NAFLD, and its prevalence is increasing with age, obesity, type 2 diabetes and hyperlipidemia. However, the molecular mechanisms of hepatic steatosis need further investigation. A team of researchers, led by Prof. Zhai Qiwei, at the Institute for Nutritional Sciences (INS), Shanghai Institutes for Biological Sciences (SIBS), CAS, found that a newly identified acetyltransferase Patt1 plays an important role in hepatic lipid metabolism. Hepatic Patt1 deficiency in male mice markedly decreases fat mass, and dramatically alleviates age-associated accumulation of lipid droplets in liver. Moreover, hepatic Patt1 abrogation in male mice significantly reduces the liver triglyceride and free fatty acid levels, but has no effect on liver cholesterol level, liver weight and liver function. Consistently, primary cultured Patt1-deficient hepatocytes are resistant to palmitic acid-induced lipid accumulation, but hepatic Patt1 deficiency fails to protect male mice from high-fat diet-induced hepatic steatosis. Further studies show that hepatic Patt1 deficiency decreases fatty acid uptake, reduces lipid synthesis and enhances fatty acid oxidation, which may contribute to the attenuated hepatic steatosis in Patt1 liver-specific knockout mice.