路基上双块式无碴轨道道床板疲劳特性影响因素分析

以路基上双块式无碴轨道为研究对象,建立钢筋与混凝土纵向相互作用力学模型、双块式无碴轨道三维有限元静力学模型、列车-双块式无碴轨道垂向耦合动力学模型.根据轴向温度荷载、混凝土收缩荷载、温度梯度荷载及列车荷载作用下道床板混凝土及钢筋应力时程曲线,运用雨流计数法,得到耦合荷载作用下的应力谱.利用Miner线性疲劳累积损伤准则...     

Regulation of the retinal interphotoreceptor matrix Na by the retinal pigment epithelium during the light response

We examined the rabbit retinal pigment epithelium (RPE) for Na transport properties which would allow it to buffer undesirable changes in Na concentrations in the interphotoreceptor matrix (IPM) during light and dark cycles. The RPE is selectivity permeable to sodium. Open and short circuit transport studies with RPE indicate a circulating (choroid to retina and back) Na current which does not compromise the electrical integrity of the blood brain barrier but together with the Na permeselectivity is of sufficient magnitude to buffer both upwards and downwards movements of IPM [Na] during light or dark responses.     

Characterization of the "4 S-trypsin" form of the cytosoluble estradiol receptor of calf uterus in a nondenaturing system]

The characterisation of the "4 S-trypsin" form of the estradiol-receptor from calf uterus cytosol was carried out by polyacrylamide gel electrophoresis under non-denaturing conditions. In a multiphasic buffer system (upper buffer Tris-glycine pH25degrees C = 8,6, lower buffer Tris HCl pH25degrees C = 7,4), three radioactive estradiol peaks were observed. The first was free estradiol, the second estradiol initially complexed with a macromolecule and dissociated during electrophoresis, and the third the hormone-receptor complex. The sedimentation coefficient (4 S) of this complex was the same before and after electrophoresis. Its mean geometric radius is R = 2.53 + 0.08 nm and its molecular weight was estimated to be 55,000.     

Influence of the viscous substance at the tip of the labellar hairs ofPhormia regina M. on the effectiveness of stimulation by cations and anions

Summary The stimulating effectiveness of salt solutions on the labellar taste hairs ofPhormia regina M. is discussed on the basis of ion diffusion properties across the mucopolysaccharidic layer at the hair tip.This work is partly supported by a grant from the Consiglio Nazionale delle Ricerche (CNR), Roma, Italy.     

超燃冲压发动机隔离段流动特性研究

本文通过数值模拟分别研究了出口反压、进口马赫数、进口附面层厚度、长高比、扩张角等对隔离段流动特性的影响。结果表明出口反压、进口附面层厚度、扩张角的增加,以及长高比的减小,可使激波串沿隔离段向上游移动;出口反压、进口马赫数以及扩张角的增加,可使隔离段总压损失增加。     

亚90nm沟道MOSFET亚阈值状态下二维电势和阈值电压的半解析模型

本文提出一个亚90nm沟道MOSFET在亚阈值状态下的二维电势和阈值电压的半解析模型．文章首先根据短沟道MOSFET在亚闽值状态下的物理模型提出定解问题,然后用特征函数将由氧化层和空间电荷区衔接条件所得到的超越方程组作正交展开,得到关于未知量的线性代数方程组．求出了氧化层和空间电荷区的二维电势、耗尽层厚度和阈值电压的表达式．该模型不需要适配参数,运算量小,避免了方程离散化,计算精度与数值解精度相同．文章给出了沟道长度为90nm以下MOSFET的电势分布、表面势、耗尽层厚度和阈值电压计算结果．计算值与二维数值模拟值高度吻合．     

Elektronenmikroskopische Untersuchung der phäochromen (chromaffinen) Granula in den Markzellen der Nebenniere

Summary The catechol-containing granules in the adrenal medullary cells (mouse, guinea pig, cat) are true cell organells, clearly distinguished from mitochondria; their size varies over a fairly wide range, the mean diameter being calculated at about 175 mµ in the mouse (osmium-tetroxide-fixation). They have a surrounding membrane of 100 Å thickness; their internal structure is finely granular. On the thin sections, many granules are surrounded by spaces which appear empty under the electron microscope and which are limited by double-membranes; it is most likely thatintra vitam these spaces contain lipids.

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Ausgeführt mit Unterstützung der Friedrich-Baur-Stiftung und der Deutschen Forschungsgemeinschaft.     

Photoreceptor damage following exposure to excess riboflavin

Flavins generate oxidants during metabolism and when exposed to light. Here we report that the photoreceptor layer of retinas from black-eyed rats is reduced in size by a dietary regime containing excess riboflavin. The effect of excess riboflavin was dose-dependent and was manifested by a decrease in photoreceptor length. This decrease was due in part to a reduction in the thickness of the outer nuclear layer, a structure formed from stacked photoreceptor nuclei. These changes were accompanied by an increase in photoreceptor outer segment autofluorescence following illumination at 328 nm, a wavelength that corresponds to the excitation maxima of oxidized lipopigments of the retinal pigment epithelium.     

聚合质量比对Sr0．7La0．15Ce0．15Fe11.7Zn0．3O19／PAn复合体系微波吸收性能的影响

用原位聚合法制备了Sr0．7La0．15Ce0．15Fe11.7Zn0．3O19铁氧体／聚苯胺（PAn）复合材料。采用X射线衍射（XRD）、扫描电子显微镜（SEM）对样品的结构、微观表面形貌和粒子大小进行了表征,用微波矢量网络分析仪测量样品在2～12．4GHZ频率范围内复介电常数和复磁导率,根据测量数据计算微波反射率R与频率f的关系。研究结果表明：PAn包覆于掺杂锶铁氧体表面,PAn／Sr0．7La0．15Ce0．15Fe11.7Zn0．3O19复合材料具有良好的吸波性能,随着掺杂锶铁氧体含量的增加,微波吸收匹配厚度和吸收带宽发生变化：当Sr0．7La0．15Ce0．15Fe11.7Zn0．3O19聚合质量比为40％时,最佳匹配厚度为2．6mm,吸收峰值接近-40dB,峰值频率高于12．4GHz,大于10dB吸收带宽预计达到55GHz。     

ArF准分子激光晶化非晶硅薄膜微结构研究

利用ArF准分子激光对非晶硅薄膜的表层进行晶化后,采用拉曼光谱(Raman)、透射电镜(TEM)、场发射扫描电子显微镜(FE-SEM)等实验方法研究不同激光能量密度下晶化层硅薄膜微结构变化。实验结果表明:随激光能量密度的增大,薄膜结晶度增大,晶化层厚度加厚;晶粒尺寸则是先增大,直到激光能量密度增大到210 mJ/cm~2后,晶粒尺寸开始减小并且均匀性逐渐变差。最佳的激光能量密度范围为120～180 mJ/cm~2,这时薄膜表面晶化层晶粒比较均匀致密,薄膜质量较好。     

基于RS GA ELM的矿井瓦斯涌出量预测

为了对煤矿井下瓦斯涌出量进行预测,采用粗糙集与改进极限学习机相结合的方法,在样本数据的筛选上吸取粗糙集数据约简的优点,充分利用极限学习机训练速度快、具有良好泛化性能的特点,并结合遗传算法选择最优的输入权值矩阵和隐含层偏差,避免随机产生所造成的误差。利用编写程序确定隐含层神经元个数,比依靠经验更为准确。在实际应用中选取煤层瓦斯含量、煤层埋藏深度、煤层厚度、煤层间距、工作面日产量五个因素作为预测的影响参数。研究结果表明:该预测模型预测的最大相对误差为5687 1%,最小相对误差为0,平均相对误差为2582 7%,相比改进前的预测模型具有更强的泛化能力和更高的预测精度。     

Isolation,characterization, and determination of human liver (copper/zinc) metallothionein

Summary A copper-containing protein was purified from the liver of a patient with primary biliary cirrhosis by a combination of gel filtration and anion exchange chromatography. This copper-protein had UV absorption and emission spectra, an amino acid composition, and a molecular mass which were characteristic for metallothionein (MT).From 8 livers (3 control, 1 fetal and 4 primary biliary cirrhosis) MT was extracted with non-reducing buffer and centrifuged, and the pellets were re-extracted with a 1% 2-mercaptoethanol-containing buffer. The non-reducing buffer extracted a predominantly copper-containing MT from the livers of patients with primary biliary cirrhosis and a predominantly zinc-containing MT from control lives and the fetal liver. Only from the fetal liver was a copper/zinc containing MT solubilized during the re-extraction with 2-mercaptoethanol-containing buffer. These results indicate that human MT is a unique metalloprotein with age and disease-dependent characteristics.     

Isolation, characterization, and determination of human liver (copper/zinc) metallothionein

A copper-containing protein was purified from the liver of a patient with primary biliary cirrhosis by a combination of gel filtration and anion exchange chromatography. This copper-protein had UV absorption and emission spectra, an amino acid composition, and a molecular mass which were characteristic for metallothionein (MT). From 8 livers (3 control, 1 fetal and 4 primary biliary cirrhosis) MT was extracted with non-reducing buffer and centrifuged, and pellets were re-extracted with a 1% 2-mercaptoethanol-containing buffer. The non-reducing buffer extracted a predominantly copper-containing MT from the livers of patients with primary biliary cirrhosis and a predominantly zinc-containing MT from control livers and the fetal liver. Only from the fetal liver was a copper/zinc containing MT solubilized during the re-extraction with 2-mercaptoethanol-containing buffer. These results indicate that human MT is a unique metalloprotein with age and disease-dependent characteristics.     

Rapid recording of the fluorescence spectrum emitted by an isolated living cell]

In order to use the selectivity of fluorescence emission for biomedical purposes, a microspectrofluorimeter has been built around an inverted microscope. The excitation is supplied by a 450 W Xenon lamp coupled with a monochromator allowing excitation from 230 to 600 nm. The fluorescence is analysed by a Grism (association prism-grating) and the spectrum focused on the 500 channels of the target of an Optical Multichannel Analyser. Related to good resolution and dispersion (0.44 nm/channel), improvement of signal to noise ratio (dark current suppression, and accumulation of spectra), this microspectrofluorimeter with high sensitivity is well adapted to the study of biological mechanism in single living cells (macrophages, monocytes, lumphocytes).     

MicroRNA degeneracy and pluripotentiality within a Lavallière-tie architecture confers robustness to gene expression networks

Modularity, feedback control, functional redundancy and bowtie architecture have been proposed as key factors that confer robustness to complex biological systems. MicroRNAs (miRNAs) are highly conserved but functionally dispensable. These antinomic properties suggest that miRNAs fine-tune gene expression rather than act as genetic switches. We synthesize published and unpublished data and hypothesize that miRNA pluripotentiality acts to buffer gene expression, while miRNA degeneracy tunes the expression of targets, thus providing robustness to gene expression networks. Furthermore, we propose a Lavallière-tie architecture by integrating signal transduction, miRNAs and protein expression data to model complex gene expression networks.     

Vanadium induced hemolysis of vitamin E deficient erythrocytes in Hepes buffer

Several vanadium compounds were tested for their ability to induce in vitro hemolysis of vitamin E-deficient hamster erythrocytes. Free vanadyl caused hemolysis in Hepes buffer but not in Tris or phosphate buffer, while hemolysis was inhibited by catalase, chelators such as deferoxamine mesylate and EDTA, and hydroxyl radical scavengers such as ethanol andd-mannitol. Although metavanadate itself could not induce hemolysis, metavanadate with NAD(P)H caused hemolysis in Hepes buffer only, and superoxide dismutase prevented it. Hydrogen peroxide, hydroxyl radical and Hepes radical were involved in vanadyl-induced hemolysis; superoxide anion was further involved in metavanadate plus NAD(P)H-induced hemolysis. Vitamin E prevented hemolysis under both conditions.     

Presence of NAD pyrophosphorylase in skeletal muscle in dystrophic mice

Summary NAD pyrophosphorylase (ATP:NMN adenylyltransferase) activity has been measured in the skeletal muscle of dystrophic mice. The amount of this enzyme in the dystrophic mice, as determined by three different methods, was about one half of that in the controls. In addition, the concentration of ATP was too low to be detected in crude extracts of dystrophic mouse skeletal muscle, which were prepared using Tris buffer alone or Tris buffer containing either 3 M KCl, or 1 mM PMSF.     

Unstirred layer thickness in perfused rat jejunum in vivo

Summary The effective unstirred layer thickness in the rat jejunum perfused in vivo amounts to at least 530 m. This value has been estimated from the absorption increase ofl-phenylalanine due to better mixing of the luminal solution by air bubbles.     

Self-labeling of human polymorphonuclear leucocyte myeloperoxidase with 125iodine.

In order to obtain a radioimmunoassay (RIA) technique for the measurement of human plasma myeloperoxidase (MPO), we purified the enzyme from polymorphonuclear granulocytes (neutrophils), and compared three methods of labeling it with 125Iodine:chloramine T, lactoperoxidase, and an original technique of 'self labeling' based on the ability of the enzyme to oxidize and bind 125I in the presence of H2O2. The chloramine T technique produced a degraded protein, as well shown by a high non-specific binding of tracer to antibody. The lactoperoxidase technique did not succeed in labeling MPO with an adequate specific activity. In contrast, the self-labeling method gave a stable tracer with a specific activity of 23 microCi/micrograms MPO (85 MBq), a satisfactory level of immunoreactivity, and a low-specific binding (less than or equal to 3%). After labeling, purification of tracer was achieved by gel filtration chromatography in phosphate buffer (0.05 M; pH7) to which 0.1% poly-L-lysine was added. The labeled molecule remained stable for 40 days and could be used for RIA with a polyclonal antibody raised in rabbits.     

Presence of NAD pyrophosphorylase in skeletal muscle in dystrophic mice

NAD pyrophosphorylase (ATP:NMN adenylyltransferase) activity has been measured in the skeletal muscle of dystrophic mice. The amount of this enzyme in the dystrophic mice, as determined by three different methods, was about one half of that in the controls. In addition, the concentration of ATP was too low to be detected in crude extracts of dystrophic mouse skeletal muscle, which were prepared using Tris buffer alone or Tris buffer containing either 3 M KCl, or 1 mM PMSF.