AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34

Congenital generalized lipodystrophy is an autosomal recessive disorder characterized by marked paucity of adipose tissue, extreme insulin resistance, hypertriglyceridemia, hepatic steatosis and early onset of diabetes. We report several different mutations of the gene (AGPAT2) encoding 1-acylglycerol-3-phosphate O-acyltransferase 2 in 20 affected individuals from 11 pedigrees of diverse ethnicities showing linkage to chromosome 9q34. The AGPAT2 enzyme catalyzes the acylation of lysophosphatidic acid to form phosphatidic acid, a key intermediate in the biosynthesis of triacylglycerol and glycerophospholipids. AGPAT2 mRNA is highly expressed in adipose tissue. We conclude that mutations in AGPAT2 may cause congenital generalized lipodystrophy by inhibiting triacylglycerol synthesis and storage in adipocytes.     

A single motif responsible for ubiquitin recognition and monoubiquitination in endocytic proteins

Ubiquitination is a post-translation modification in which ubiquitin chains or single ubiquitin molecules are appended to target proteins, giving rise to poly- or monoubiquitination, respectively. Polyubiquitination targets proteins for destruction by the proteasome. The role of monoubiquitination is less understood, although a function in membrane trafficking is emerging, at least in yeast. Here we report that a short amino-acid stretch at the carboxy-termini of the monoubiquitinated endocytic proteins Eps15 and eps15R is indispensable for their monoubiquitination. A similar sequence, also required for this modification, is found in other cytosolic endocytic proteins, such as epsins and Hrs. These sequences comprise a protein motif, UIM (ref. 6), which has been proposed to bind to ubiquitin. We confirm this for the UIMs of eps15, eps15R, epsins and Hrs. Thus, the same motif in several endocytic proteins is responsible for ubiquitin recognition and monoubiquitination. Our results predict the existence of a UIM:ubiquitin-based intracellular network. Eps15/eps15R, epsins and Hrs may function as adaptors between ubiquitinated membrane cargo and either the clathrin coat or other endocytic scaffolds. In addition, through their own ubiquitination, they may further contribute to the amplification of this network in the endocytic pathway.     

LiNbO_3基片上准纵模声表面漏波的研究

对高声速材料，高声速的声波模式研究已成为实现高频ＳＡＷ器件的重要方向之一．众所周知，一般的纵声波的速度是ＳＡＷ声速的两倍．因此对准纵模表面漏波的研究就引起了人们的注意．本文以ＬｉＮｂＯ３样品为例进行了一些搜索，发现在欧勒角为α＝０°，β，γ＝９０°的某些范围内，它的声速可高达７０００ｍ／ｓ，机电耦合系数可在０．１４％左右，自由化表面和金属化表面的衰减都非常小，并在实验上得到了证实．     

瓦楞形状及参数对瓦楞纸板性能的影响

对几种形状瓦楞进行了计算，分析了瓦楞形状参数对瓦楞纸板缓冲性能、结构强度和材料消耗量的影响，得到了一种较好的瓦楞形状．     

冷核聚变反应截面的测量原理与实验方法

本文对冷核聚变反应截面的测量原理与实验方法进行了详细地讨论，为证实冷核聚变是否存在提供了一条可能的途径，本文所提供的原理与方法，在电化学方面也有一定的实用价值。     

影响浮选旋流器浮选效果的因素分析

由溢流口和底流口的面积比、入料压力和原矿浓度的变化对浮选旋流器内部物料流态及浮选效果影响的定性分析,得到其变化规律。这有助于浮选旋流器的进一步完善。     

16kb／sATM话音分组通信技术

结合１６ｋｂ／ｓ话音子带编码的特点，提出了一种建立在该编码算法基础上的ＡＴＭ（异步转移模式）话音信元装配方法及相应的信元丢失补偿技术，并给出了计算机模拟实验结果     

双脉冲电位法制备铜镍层状结构材料

采用旋转圆盘电极，用双脉冲电位法从简单的镀液中电沉积Ｃｕ－Ｎｉ层状材料，研究了镀液中铜含量、添加剂、转速对镀层的组成和结构的影响，并用扫描电镀和Ｘ－射线衍射研究了镀层的形貌和组成。     

规模报酬递减下的企业研发行为与政府政策

在质量阶梯模型的基础上，通过引入SZ模型讨论了企业研发投资规模报酬递减条件下企业研发行为和政府的研发政策，为领先企业提供研发补贴并对后来居上的企业征税，可以实现研发资源配置的帕累托最优。补贴率和征税率取决于领先企业的研发成本优势和产品需求弹性。对模型结论进行了必要的分析和修正，并结合我国产业现状指出，适当下放研发激励政策制定权限，针对企业实施事前差别性补贴应是进一步的改革方向。     

IT项目风险管理理论体系构建

文章论证了IT项目风险管理与所基于的计算机科学、管理学和经济学中各相关学科的关系,回顾与分析了Boehm、Charette和SEI 3种典型软件项目风险管理体系,接着从方法论角度阐明了学科思想、学科体系设计机理和设计准则,最后构建了全面IT项目风险管理体系.