A missense mutation in Tbce causes progressive motor neuronopathy in mice

Mice that are homozygous with respect to the progressive motor neuronopathy (pmn) mutation (chromosome 13) develop a progressive caudio-cranial degeneration of their motor axons from the age of two weeks and die four to six weeks after birth. The mutation is fully penetrant, and expressivity does not depend on the genetic background. Based on its pathological features, the pmn mutation has been considered an excellent model for the autosomal recessive proximal childhood form of spinal muscular atrophy (SMA). Previously, we demonstrated that the genes responsible for these disorders were not orthologous. Here, we identify the pmn mutation as resulting in a Trp524Gly substitution at the last residue of the tubulin-specific chaperone e (Tbce) protein that leads to decreased protein stability. Electron microscopy of the sciatic and phrenic nerves of affected mice showed a reduced number of microtubules, probably due to defective stabilization. Transgenic complementation with a wildtype Tbce cDNA restored a normal phenotype in mutant mice. Our observations indicate that Tbce is critical for the maintenance of microtubules in mouse motor axons, and suggest that altered function of tubulin cofactors might be implicated in human motor neuron diseases.     

红外图像序列动态帧间滤波技术

该文提出了红外图像序列的动态帧间滤波技术,把图像序列作为二维数据流,采用先进先出的方式在整个积分周期内进行多帧平均,实现了沿着运动轨迹进行帧间滤波。对于活动红外图像序列,该技术能够有效地抑制噪声、提高信噪比,也能够降低运动目标的模糊程度。     

初中新生入学适应的发展研究

经纵向研究发现：初中新生的入学适应水平并非随时间的推移逐渐提高,而是呈“V”型趋势发展,即由适应——不适应——适应的过程发展,且各维度的适应水平也不平衡．学校和教师应根据新生的入学适应特点和发展规律,适当延长入学教育指导时间,重视入学后第二、三个月的适应指导,对症下药,走出入学适应指导误区。     

大学生社交效能感量表的初步编制研究

本研究通过探索性因素分析抽取了大学生社交效能感量表的5个因素,分别是应对陌生人、社交信心、亲和力、社交主动、应对社交困境,再通过验证性因素分析检验,确定了量表五因素结构模型.通过信效度分析,表明量表具有较好的稳定性和有效性,达到了心理测量学的要求,可以用于大学生社交效能感状况的测量,为大学生社交效能感的进一步研究提供了研究工具.     

Diet control on carbon isotopic composition of land snail shell carbonate

Carbon isotope compositions for both the carbonate shells and soft bodies (organic tissue) of living land snails collected mostly from the Loess Plateau, China have been measured. The result shows that δ 13C values range from -13.1‰ to -4.3‰ for the aragonite shell samples and from -26.8‰ to -18.0‰ for the soft body samples. Although the shells are enriched in 13C relative to the bodies averagely by 14.2(±0.8)‰, the shell δ 13Ca values are closely correlated to the body δ 13Corg values, expressed as δ 13Ca = 1.021 δ 13Corg 14.38 (R = 0.965; N = 31). This relationship indicates that δ 13Ca is primarily a function of the isotopic composition of the snail diets since previous studies have proved that the snail body is the same as their food in carbon isotope composition. In other words, carbon isotope compo-sition of the carbonate shell can be used as a proxy to estimate the dietary 13C abundance of the land snails. The data also support that the 13C enrichment of the carbonate shells results mainly from the equilibrium fractionations between the metabolic CO2, HCO3-in the hemolymph and shell aragonite, and partially from kinetic fractionations when snail shells form during their activity.     

Biocompatibility studies of silk fibroin-based artificial nerve grafts in vitro and in vivo

Silk fibroin(SF)has been used extensively in the biomedical field including tissue engineering for the generation of artificial bones,skins or ligaments.We have previously reported on good in vitro biocompatibility of SF fibers with peripheral nerve tissues and cells.In the present study,we developed a novel design of the SF-based artificial nerve graft(SF graft)which was composed of a SF-nerve guidance conduit(NGC)inserted with SF fibers.MTT assay was performed to determine the cytotoxicity of the SF-NGC extract fluid on the cultured L929 cells derived from an immortalized mouse fibroblast cell line.In addition,this SF graft was implanted into adult rats for bridging a 10-mm long sciatic nerve defect.The following-up experiments at initial stage(1-4 week)of nerve regeneration including routine blood tests and histochemical investigation were conducted to evaluate the in vivo biocompatibility of the SF graft with peripheral nerves.The results demonstrated that the SF-NGC graft was biocompatible with the surrounding tissues and cells due to its low inflammatory potential with a grade 0 under the U.S.Pharmacopeia guidelines and it was generally suitable to a certain degree for bridging peripheral nerve defects in virtue of supporting Schwann cell adherence,expansion and migration.Therefore the SF graft is a promising alternative to classical autografts for peripheral nerve repair.     

A thermal insulation method for a piezoelectric transducer

This study deals with the sources of signal distortion of a piezoelectric transducer heated by measured gas flow. These signal distortions originate from both unloading of preload on a piezocrystal because of expansion of a diaphragm in the test apparatus and the pyroelectric effect of a heated piezoelectric crystal. A plastic film on the diaphragm of the transducer can effectively insulate the diaphragm and the piezocrystal within transducer from heating by gas flow, eliminating the sources of distortion. A method for evaluating the thickness of the film is proposed.     

西秦岭厂坝-李家沟铅锌矿矿床地质特征和成因分析

摘要：厂坝一李家沟矿床规模巨大，是秦岭地区西成铅锌成矿带的重要矿床之一。矿体形态和规模明显受沉积洼地控制。矿石常显微莓球状、针状、他形隐晶质、显微球粒结构。可识别的矿石沉积一成矿作用构造有浸染一条带状、条纹一条带状、隐晶质条带、条块状、块状构造等。矿体中下部主要为块状矿石，富黄铁矿、闪锌矿、钠长石和石英；上部为条带状、浸染状和层纹状矿石，富闪锌矿、重晶石和方解石。条带状的石英钠长石岩和重晶石所含的典型喷气元素B和As的含量比正常沉积岩高出几倍到几十倍。闪锌矿中Zn／Cd〉〉500，黄铁矿中Co／Ni为O．2～O．8。另外，该矿主要形成于受裂谷控制的克拉通内部及其边缘的沉降盆地。结果表明，厂坝矿具有较典型的Sedex型矿床特征。[第一段]     

交联聚苯乙烯粒子的中空结构及其分析

以含有油性添加物的苯乙烯-二乙烯基苯悬浮聚合制备交联聚苯乙烯中空粒子.通过对干燥后再溶胀的粒子的热失重分析,借助于粒子中溶胀的异辛烷的释放特性及其释放速率的变化规律,探讨了聚合中单体组成、添加物性质等因素对粒子中空结构形成及其壳层结构的影响.结果显示,易与聚苯乙烯链形成相分离的异辛烷可以产生单中空结构的粒子,并且发现,中空粒子中溶胀物的释放可分为两个具有不同速率特征的阶段,二乙烯基苯的含量会对中空粒子空腔形态与壳壁结构产生进一步的影响.     

粘胶纤维切断刀的腐蚀磨损与寿命

本文分析了粘胶纤维切断刀的腐蚀磨损形貌,并将几种钢经不同表面处理后进行试验。结果表明:镀覆 TiN 的 Cr15Ni18Mo2Cu3或1Cr18Ni12Mo2Ti 不锈钢切断刀能显著提高其寿命。