Dislocation behaviors are analyzed in AlGaN/GaN multiple-quantum-well films grown with different strain-modified interlayers.In the case of multiple-quantum-well layers grown on a GaN buffer layer without the interlay...Dislocation behaviors are analyzed in AlGaN/GaN multiple-quantum-well films grown with different strain-modified interlayers.In the case of multiple-quantum-well layers grown on a GaN buffer layer without the interlayer,many threading dislocations interact and annihilate within about 100 nm below the multiple quantum well layer.For multiple-quantum-well layers grown with the AlGaN interlayer,misfit dislocations between the GaN buffer layer and the AlGaN interlayer enter multiple-quantum-well layers and result in an increase of threading dislocation density.Besides misfit dislocations,the edge-type dislocation is another dislocation origin attributed to the dissociation of Shockley partials bounding the stacking fault in AlN/GaN superlattices below the interlayer interface.展开更多
Background Little is known about the influence of metabolic syndrome （MetS） on coronary artery calcification （CAC） in China. In this article, we aimed to explore the distribution of CAC in populations with and wit...Background Little is known about the influence of metabolic syndrome （MetS） on coronary artery calcification （CAC） in China. In this article, we aimed to explore the distribution of CAC in populations with and without MetS, and estimate the influence of MetS and its components on CAC in a community-based population of Beijing. Methods A total of 1647 local residents of Beijing, age 40-77 years, were recruited for a cardiovascular risk factors survey and were determined fasting plasma glucose （FPG）, blood lipids, and 64 multi-detector computed tomography （64-MDCT） coronary artery calcium score （CACS） measurement （Agatston scoring）. The distribution of CAC was described, and the influence of MetS components on CAC was evaluated. Results In this population, the prevalence and extent of CAC increased with increasing age and both were higher in MetS subjects compared to nonMetS subjects （all P 〈0.05）, with the exception of those older than 65 years old. The risk of CAC increased with increasing numbers of MetS components, and the odds ratios for predicting positive CAC in subjects with 1, 2, 3, and 〉4 MetS components were 1.60, 1.84, 2.12, and 3.12, respectively （all P 〈0.05）. Elevated blood pressure, elevated FPG, elevated triglycerides, and overweight increased the risk of CAC, yielding odds ratios of 2.64, 1.67, 1.32, and 1.37, respectively （all P 〈0.05）. Conclusions In the Beijing community-based population, MetS increases the risk of CAC. The risk of CAC increases with increasing numbers of MetS components. Not only the number, but also the variety of risk factors for MetS is correlated with the risk of CAC. Elevated blood pressure, hyperglycemia, hypertriglyceridemia and overweight increase the risk of CAC.展开更多
基金Supported by the Natural Science Foundation of Heilongjiang Province under Grant No F2007-1the Open Experimentation Program of Beijing Institute of Technology(BJUT-GTS-200904).
文摘Dislocation behaviors are analyzed in AlGaN/GaN multiple-quantum-well films grown with different strain-modified interlayers.In the case of multiple-quantum-well layers grown on a GaN buffer layer without the interlayer,many threading dislocations interact and annihilate within about 100 nm below the multiple quantum well layer.For multiple-quantum-well layers grown with the AlGaN interlayer,misfit dislocations between the GaN buffer layer and the AlGaN interlayer enter multiple-quantum-well layers and result in an increase of threading dislocation density.Besides misfit dislocations,the edge-type dislocation is another dislocation origin attributed to the dissociation of Shockley partials bounding the stacking fault in AlN/GaN superlattices below the interlayer interface.
文摘Background Little is known about the influence of metabolic syndrome （MetS） on coronary artery calcification （CAC） in China. In this article, we aimed to explore the distribution of CAC in populations with and without MetS, and estimate the influence of MetS and its components on CAC in a community-based population of Beijing. Methods A total of 1647 local residents of Beijing, age 40-77 years, were recruited for a cardiovascular risk factors survey and were determined fasting plasma glucose （FPG）, blood lipids, and 64 multi-detector computed tomography （64-MDCT） coronary artery calcium score （CACS） measurement （Agatston scoring）. The distribution of CAC was described, and the influence of MetS components on CAC was evaluated. Results In this population, the prevalence and extent of CAC increased with increasing age and both were higher in MetS subjects compared to nonMetS subjects （all P 〈0.05）, with the exception of those older than 65 years old. The risk of CAC increased with increasing numbers of MetS components, and the odds ratios for predicting positive CAC in subjects with 1, 2, 3, and 〉4 MetS components were 1.60, 1.84, 2.12, and 3.12, respectively （all P 〈0.05）. Elevated blood pressure, elevated FPG, elevated triglycerides, and overweight increased the risk of CAC, yielding odds ratios of 2.64, 1.67, 1.32, and 1.37, respectively （all P 〈0.05）. Conclusions In the Beijing community-based population, MetS increases the risk of CAC. The risk of CAC increases with increasing numbers of MetS components. Not only the number, but also the variety of risk factors for MetS is correlated with the risk of CAC. Elevated blood pressure, hyperglycemia, hypertriglyceridemia and overweight increase the risk of CAC.
