A complex of Shc and Ran-GTPase localises to the cell nucleus

The three isoforms of the adaptor protein Shc play diverse roles in cell signalling. For example, the observation of p46 Shc in the nuclei of hepatocellular carcinoma cells suggests a function quite distinct from the better characterised cytoplasmic role. Ligands responsible for the transport of various Shc isoforms into organelles such as the nucleus have yet to be reported. To identify such ligands a far western approach was used to determine the p52 Shc interactome. The Ran-GTPase nuclear transport protein was identified and found to bind to p52 Shc in vitro with low micromolar affinity. Co-immunoprecipitation, pull down and fluorescence lifetime imaging microscopy experiments in stable cells confirmed cellular interaction and nuclear localisation. The nuclear transport factor protein NTF2, which functions in cohort with Ran, was shown to form a complex with both RAN and Shc, suggesting a mechanism for Shc entry into the nucleus as part of a tertiary complex. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 20 October 2008; received after revision 04 December 2008; accepted 15 December 2008     

Homozygous L-SIGN (CLEC4M) plays a protective role in SARS coronavirus infection

Severe acute respiratory syndrome (SARS) is caused by infection of a previously undescribed coronavirus (CoV). L-SIGN, encoded by CLEC4M (also known as CD209L), is a SARS-CoV binding receptor that has polymorphism in its extracellular neck region encoded by the tandem repeat domain in exon 4. Our genetic risk association study shows that individuals homozygous for CLEC4M tandem repeats are less susceptible to SARS infection. L-SIGN is expressed in both non-SARS and SARS-CoV-infected lung. Compared with cells heterozygous for L-SIGN, cells homozygous for L-SIGN show higher binding capacity for SARS-CoV, higher proteasome-dependent viral degradation and a lower capacity for trans infection. Thus, homozygosity for L-SIGN plays a protective role during SARS infection.     

关于Kuratowski十四集定理的一个注记

作者给出了Kuratowski十四集定理的又一个等价形式,并进一步证明了拓扑空间(X,τ)中的任意子集经过取内部和闭包两种运算至多可产生7个不同的集合(包含A本身)。     

基于AlN压电层的薄膜体声波谐振器

以AlN薄膜为压电层,采用体硅微细加工工艺制备背空腔型结构薄膜体声波谐振器.材料测试结果表明,在优化溅射工艺下沉积的AlN薄膜具有(002)择优取向及良好的柱状晶结构.扫描电镜表征结果证实所制得空腔背部平滑且各向异性较好.用网络分析仪测试可知,所制得的谐振器具有较好的频率特性:谐振频率为2.537 GHz,机电耦合系数3.75%,串、并联品质因数分别为101.8、79.7.     

气相色谱–离子迁移谱分析微囊藻的挥发性成分

建立顶空–气相色谱–离子迁移谱（headspace-gas chromatography-ion mobility spectrometry,HS-GC-IMS）方法，比较了不同生长时期的微囊藻挥发性物质差异。根据离子迁移谱图结果，结合化学计量学方法对比挥发性有机化合物，通过其指纹谱图观察挥发性物质相对含量的变化规律。结果表明，挥发性成分的GC-IMS谱图存在明显差异，前2个主成分累计贡献率达到78.4%。从微囊藻水华样品中共鉴定出91种挥发性成分，其中包括醛类23种、醇类21种、酯类16种、酮类10种、硫醚类7种、酸类2种、萜烯类2种，其中1-丁醇、(E,E)–2,4–癸二烯醛、乙酸、二甲基硫醚、(E)–3–己烯–1–醇、1–辛烯–3–酮等是微囊藻水华特征挥发性差异物。本方法操作简便快速，灵敏度高，可用于藻类水华时挥发性代谢物的筛查及确证，为环境监测提供数据支持。     

Heisenberg李代数的形心

Heisenberg李代数是一类重要的可解李代数, 有深刻的物理背景, 因而也是李代数研究的重要对象之一. 李代数的形心是研究李代数结构的必要工具. 特别地，形心具有自然的环结构，其所有可逆形心构成一个群. 本文讨论了有限维和无限维Heisenberg李代数的形心及其结构.