The effect of ligand on the kinetics of the reaction of the sulfhydryl groups of human hemoglobin with p-mercuribenzoate

Summary The rate of reaction of PMB with the masked sulfhydryls of human hemoglobin derivatives correlates well with the extent of dissociation for various ligands. It is suggested that the ₁₂ dimer of hemoglobin participates in the slow step of the reaction with PMB.     

分层实体制造中金属分层板结合的新方法

针对金属造型材料分层快速制造方法中存在的问题，提出用真空固态压力热扩散焊接金属分层板的新方法。实验研究表明：焊接后堆积成形方向上零件尺寸变化较小，且为系统误差，其数值仅为1%；结合区域原子发生了明显扩散，新的晶料组织已经形成；焊缝结合强度在100Mpa以上，显微硬度与母材一致。研究结果表明真空固态压力热扩散焊是比较理想的金属分层板连接工艺。     

受噪声影响的模糊样本学习理论的关键定理

统计学习理论是一种较好的小样本统计理论,它所处理的数据是随机样本.考虑到现实世界的模糊性,把统计学习理论中的样本从随机样本扩展到模糊样本既有理论意义又有应用价值.然而目前基于模糊样本的统计学习理论的研究,总是假定所处理的样本不受噪声的影响,从而不会引起误差,但由于人为、环境等因素的影响,事实往往并非如此.基于此种考虑,本文给出了受噪声影响的模糊样本的统计学习理论的关键定理.     

Farnesylation of Pex19p is not essential for peroxisome biogenesis in yeast and mammalian cells

Pex19p exhibits a broad binding specificity for peroxisomal membrane proteins (PMPs), and is essential for the formation of functional peroxisomal membranes. Pex19p orthologues contain a C-terminal CAAX motif common to prenylated proteins. In addition, Saccharomyces cerevisiae and Chinese hamster Pex19p are at least partially farnesylated in vivo. Whether farnesylation of Pex19p plays an essential or merely ancillary role in peroxisome biogenesis is currently not clear. Here, we show that (i) nonfarnesylated and farnesylated human Pex19p display a similar affinity towards a select set of PMPs, (ii) a variant of Pex19p lacking a functional farnesylation motif is able to restore peroxisome biogenesis in Pex19p-deficient cells, and (iii) peroxisome protein import is not affected in yeast and mammalian cells defective in one of the enzymes involved in the farnesylation pathway. Summarized, these observations indicate that the CAAX box-mediated processing steps of Pex19p are dispensable for peroxisome biogenesis in yeast and mammalian cells. Received 10 March 2006; received after revision 28 April 2006; accepted 30 May 2006     

Antifungal properties of taxol and various analogues.

The antimitotic agent taxol was tested for toxicity towards fungi from different taxonomic groups and found to be particularly active against oomycete fungi. In germinating zoospore cysts of the oomycete Phytophthora capsici the mechanism of action of taxol was shown to involve inhibition of mitosis, presumably resulting from an effect on microtubules. Various taxol analogues with deleted A-ring C-13 side chain substituents were tested for toxicity towards P. capsici and Aphanomyces cochlioides to provide insight into structural features required for activity. The importance of the side chain was shown by the much lower activity as compared to taxol of analogues lacking all or part of the side chain. The effect of stereochemistry at the C-2' position on fungitoxicity towards oomycetes was similar to that reported previously on mammalian microtubule assembly.     

面向集成管理网的TMN-DCN拓扑结构设计

提出了各种网络集成管理的TMN—DCN设计方法，并举出了应用示例。TMN—DCN设备可按各个网络配置。这些设备具有网络管理功能。规模非常大的网络分配多个TMN—DCN设备。下一阶段则利用作为TMN-DCN节点的TMN-DCN设备设计TMN—DCN的布局（物理结构）。     

Mutations in NYX, encoding the leucine-rich proteoglycan nyctalopin, cause X-linked complete congenital stationary night blindness

During development, visual photoreceptors, bipolar cells and other neurons establish connections within the retina enabling the eye to process visual images over approximately 7 log units of illumination. Within the retina, cells that respond to light increment and light decrement are separated into ON- and OFF-pathways. Hereditary diseases are known to disturb these retinal pathways, causing either progressive degeneration or stationary deficits. Congenital stationary night blindness (CSNB) is a group of stable retinal disorders that are characterized by abnormal night vision. Genetic subtypes of CSNB have been defined and different disease actions have been postulated. The molecular bases have been elucidated in several subtypes, providing a better understanding of the disease mechanisms and developmental retinal neurobiology. Here we have studied 22 families with 'complete' X-linked CSNB (CSNB1; MIM 310500; ref. 4) in which affected males have night blindness, some photopic vision loss and a defect of the ON-pathway. We have found 14 different mutations, including 1 founder mutation in 7 families from the United States, in a novel candidate gene, NYX. NYX, which encodes a glycosylphosphatidyl (GPI)-anchored protein called nyctalopin, is a new and unique member of the small leucine-rich proteoglycan (SLRP) family. The role of other SLRP proteins suggests that mutant nyctalopin disrupts developing retinal interconnections involving the ON-bipolar cells, leading to the visual losses seen in patients with complete CSNB.