Prolongation of response of node of Ranvier by metal ions

The response of the node of Ranvier can be prolonged up to 5 to 6 seconds by addition to the medium of minute amounts of certain metal ions. This prolongation involves a change from a triangular to a rectangular configuration. The properties of the prolonged nerve-fiber responses are very similar to those of heart muscle.     

Neuroblastoma: synchronization of neurite outgrowth in cultures grown on collagen

Neurite outgrowth in cultured neuroblastoma cells is inhibited in cells grown on a collagen substratum as compared to those grown on glass. Rapid, synchronized initiation of neurite outgrowth occurs after hydrolysis of the underlying collagen with collagenase. Axonated cultures exhibit an increased RNA and protein content as compared to cultures grown on collagen.     

Synapse Arising at Central Node of Ranvier, and Note on Fixation of the Central Nervous System

The discovery in electron micrographs of a synaptic bouton arising directly from a node of Ranvier in the motor horn of the monkey spinal cord, and of a node covered by extensions of two outer lamellae of the myelin sheath, suggests a degree of variation of central nodal structure and development not usually attributed to nodes of Ranvier.     

构建高校预防腐败体系与机制的探讨

根据高校反腐倡廉工作的特点,提出了要从加强思想教育、制度建设、权力监督、实施过程预防等4个方面入手,建立高校预防腐败的自律机制、约束机制、制衡机制、预警机制等4个机制,以构建较完善的高校预防腐败体系与机制。     

Permeability and structure of junctional membranes at an electrotonic synapse

The dye Procion Yellow M4RS crosses junctional membranes from cytoplasm to cytoplasm at electrotonic synapses between segments of the crayfish septate axon. The dye does not enter the cells from extracellular space. Thus permeability of junctional membranes is qualitatively different from that of nonjunctional membranes. Electron microscopy after fixation in the presence of lanthanum hydroxide indicates that these synapses are "gap junctions" and that there is a network of channels continuous with extracellular space between apposed junctional membranes. These channels must be interlaced with intercytoplasmic channels that are not open to extracellular space.     

黎藤节间与节部纤维形态特征的径向变化

为了更好地指导藤材的合理利用,缓解日益紧张的木材供需矛盾,采用显微图像分析方法,对3组黎藤试样2m处藤节间与节部的纤维形态特征进行了观察与统计,并进行对比与分析。结果显示,黎藤节间与节部纤维的长度、宽度、长宽比、腔径、双壁厚分别为981.779和921.271μm、7.786和8.719μm、130.822和113.021、3.716和3.669μm、4.070和5.051μm。由藤芯到藤皮节间处纤维长度和长宽比均呈现先增后降的趋势,节部处纤维长度和长宽比、节间纤维宽度均呈现逐渐下降的趋势;节间、节部处纤维腔径及节部宽度均呈现先降后增的趋势;节间处双壁厚呈现逐渐下降的趋势,节部处双壁厚呈逐渐增加的趋势。经F检验,在0.05水平上节间与节部处纤维宽度和双壁厚存在极显著差异。平均纤维微纤丝角为42.71°,变化区间在39.38°～46.03°;平均纤维素结晶度为46.96%,变化区间在44.10%～49.82%,且藤皮处结晶度大于藤芯处。     

大豆落花落荚及荚而不实的原因及预防措施

大豆落花落荚及荚而不实是影响大豆产量难以提高的主要因素之一,笔者通过对其发生原因的分析,有针对性地提出了预防措施。     

种子贮藏期间的发热与防控

本文详尽分析了种子贮藏期间发热的原因，并提出了防止种子发热的具体措施。     

新老大豆品种不同节位叶片性状及其与籽粒产量的相关性研究

【目的】分析新老大豆品种各生育期不同节位产量及叶片性状的变化,为吉林省大豆高产育种和栽培提供理论依据。【方法】以1929年育成品种元宝金、1941年育成品种金元1号、1999年育成品种吉农7号和2000年育成品种吉林45号为材料,比较新老品种不同节位产量与净光合速率、叶面积、光合能力、叶片干质量、比叶质量和叶绿素含量的变化及其相关性。【结果】各大豆品种在整个生育期间不同节位的叶片性状不同;元宝金和金元1号在生育前期中下部节位叶片的叶面积大,净光合速率、光合能力和叶绿素含量高,而生育后期叶片功能下降较快;吉农7号和吉林45号在生育后期中上部节位叶片的叶面积大,净光合速率、光合能力和叶绿素含量高,叶片功能持续期长,这些节位的产量也比较高;元宝金和金元1号的产量与净光合速率、叶面积、光合能力、叶片干质量和比叶质量呈极显著正相关;吉农7号和吉林45号的产量与净光合速率、叶面积、光合能力和叶绿素含量呈极显著正相关,且相关性较2个老品种更密切。【结论】吉农7号和吉林45号产量提高是由于中上部节位的净光合速率、叶面积、光合能力和叶绿素含量得以改善的结果。     

Immunologic tolerance: role of the regional lymph node

Dansyl chloride, a skin setnsitizer when injected in complete Freund's adjuvant, induced marked tolerance and no sensitization when applied to the intact skin of guinea pigs. Application of this chemical to alymphatic skin islands failed to induce tolerance or sensitization. Lymnphatic connections between skin and regional lymph nodes were essential for the developmnent of ismmunologic toleance.     

加强会计诚信建设预防会计信息失真

通过分析会计信息失真的原因和笃守会计诚信的重要性,从强化法律意识,完善监督机制,提高人员素质,健全法律法规,推行会计委派制5方面提出了预防会计信息失真的对策。     

Infrared spectra and the chain organization of erythrocyte membranes

Changes in the intensity of the 720 cm(-1) band were followed in the infrared spectra of the human erythrocyte membrane and its total lipid extract, recorded at various temperatures. These changes are interpreted in terms of the configuration of the lipid hydrocarbon chains within the membrane. Effects of temperature, sonication, removal of lipids, and organic solvents on the amide I and II bands, associated with protein conformations, were also studied.     

Otolithic membranes of the saccule and utricle in man

The otolithic membranes of the human saccule and utricle can be prepared as whole mounts or surface specimens for microscopic examination. They are not simple, homogeneous, gelatinous structures as heretofore described. Instead, each shows a definite and characteristic fibrillar design, which appears to be correlated with the known cytoarchitectural pattern of the underlying neuroepithelium.     

柑桔主要病虫害防治

柑桔是红河州的一大果种,柑桔病虫害的防治是生产管理中的一个重要环节,结合红河州生产实际,根据作者多年生产管理经验,总结柑桔生产管理中主要的几种病虫害防治方法,供参考.     

The fluid mosaic model of the structure of cell membranes

A fluid mosaic model is presented for the gross organization and structure of the proteins and lipids of biological membranes. The model is consistent with the restrictions imposed by thermodynamics. In this model, the proteins that are integral to the membrane are a heterogeneous set of globular molecules, each arranged in an amphipathic structure, that is, with the ionic and highly polar groups protruding from the membrane into the aqueous phase, and the nonpolar groups largely buried in the hydrophobic interior of the membrane. These globular molecules are partially embedded in a matrix of phospholipid. The bulk of the phospholipid is organized as a discontinuous, fluid bilayer, although a small fraction of the lipid may interact specifically with the membrane proteins. The fluid mosaic structure is therefore formally analogous to a two-dimensional oriented solution of integral proteins (or lipoproteins) in the viscous phospholipid bilayer solvent. Recent experiments with a wide variety of techniqes and several different membrane systems are described, all of which abet consistent with, and add much detail to, the fluid mosaic model. It therefore seems appropriate to suggest possible mechanisms for various membrane functions and membrane-mediated phenomena in the light of the model. As examples, experimentally testable mechanisms are suggested for cell surface changes in malignant transformation, and for cooperative effects exhibited in the interactions of membranes with some specific ligands. Note added in proof: Since this article was written, we have obtained electron microscopic evidence (69) that the concanavalin A binding sites on the membranes of SV40 virus-transformed mouse fibroblasts (3T3 cells) are more clustered than the sites on the membranes of normal cells, as predicted by the hypothesis represented in Fig. 7B. T-here has also appeared a study by Taylor et al. (70) showing the remarkable effects produced on lymphocytes by the addition of antibodies directed to their surface immunoglobulin molecules. The antibodies induce a redistribution and pinocytosis of these surface immunoglobulins, so that within about 30 minutes at 37 degrees C the surface immunoglobulins are completely swept out of the membrane. These effects do not occur, however, if the bivalent antibodies are replaced by their univalent Fab fragments or if the antibody experiments are carried out at 0 degrees C instead of 37 degrees C. These and related results strongly indicate that the bivalent antibodies produce an aggregation of the surface immunoglobulin molecules in the plane of the membrane, which can occur only if the immunoglobulin molecules are free to diffuse in the membrane. This aggregation then appears to trigger off the pinocytosis of the membrane components by some unknown mechanism. Such membrane transformations may be of crucial importance in the induction of an antibody response to an antigen, as well as iv other processes of cell differentiation.     

完善企业内部控制制度治理会计信息失真

在市场经济中,由于所有权和经营权分离的情况下,使得会计信息失真有其存在的客观性和必然性,报表提供者与使用者的利益常常不同,前者可能提供虚假的会计信息,而愚弄报表使用者,从而使后者做出错误的决策。因此,关键是如何采取适当地措施来完善企业内部控制制度,有效的治理会计信息失真。