Ion channels in cultured microglia

Inward and, depending on activation state, outward potassium currents are the dominant ion channels in microglial cells in culture. During transition between resting and activated phases, there is also an upregulated expression of stretch/swelling-activated chloride currents. Pharmacological blockade of the specific potassium channels does not prevent the transition, whereas blockade of chloride channels does, suggesting that this current may be involved in phase changes. Interestingly, this chloride current is far less studied than the potassium currents with regard to the different microglial phases. One puzzling finding when studying microglial state is that despite changes in current densities and membrane oscillations during transition, there is no evidence of an accompanying change in membrane potential. In other cells of the immune system, membrane oscillations and alterations in membrane potential are correlated with transitions in cellular phases. This discrepancy in microglia may be a result of the fact that almost all ion channel and membrane potential studies in culture are undertaken with concomitant dialysis of cytoplasm with pipette solution. Further complicating matters is that the few studies that use microglia in situ, find fundamental differences in ion channel current patterns of "resting" microglia as well as different temporal changes to pathological events or stimuli.     

Role of microglia in glioma biology.

Microglia, a type of differentiated tissue macrophage, are considered to be the most plastic cell population of the central nervous system (CNS). In response to pathological conditions, resting microglia undergo a stereotypic activation process and become capable of phagocytosis, antigen presentation, and lymphocyte activation. Considering their immune effector function, it is not surprising to see microglia accumulation in almost every CNS disease process, including malignant brain tumors or malignant gliomas. Although the function of these cells in CNS inflammatory processes is being studied, their role in malignant glioma biology remains unclear. On one hand, microglia may represent a CNS anti-tumor response, which is inactivated by local secretion of immunosuppressive factors by glioma cells. On the other hand, taking into account that microglia are capable of secreting a variety of immunomodulatory cytokines, it is possible that they are attracted by gliomas to promote tumor growth. A better understanding of microglia-glioma interaction will be helpful in designing novel immune-based therapies against these fatal tumors.     

A modification of microglia impregnation (author's transl)]

A modification of the Weil and Davenport (1933) silver carbonate method for microglia impregnation is described. Formalin-dextran-CaCl2 solution was used as a fixation solution. The technique is simple, reproducible and improved. The staining method includes the demonstration of as well resting as progressive microglia.     

IEC百年起因与创新——竞争与和谐

要做与国际接轨的创新，必须知其然，更需知其所以然。     

The Nature and Origin of Tribochemistry

Tribochemistry can be defined as the chemical reactions that occur between the lubricant/environment and the surfaces under boundary lubrication conditions. The precise nature of the chemical reactions is not well understood. What causes the reactions to take place is also a subject of speculation. Surface analysis of the surface and the reaction products yields insufficient information for a full understanding of the nature and origin of the chemical reactions. The reaction mixture is complex and the quantity is very small. Classical analytical techniques provide elemental concentration but the organic portion of the reaction products eludes definition. Recent observation of surface emissions of electrons, charged particles, from rubbing surfaces invites speculation that this emission provides the source of energy causing tribochemical reactions to take place. This study reviews our current knowledge of tribochemistry and examines the issue of the source of tribochemistry in boundary lubrication. Experiments were designed to examine the issue of whether mechanical disruption of surface bonds can lead to the formation of reaction products. The second issue is whether these reaction products correspond to those observed under normal rubbing conditions. Thermally induced reaction products were also examined for comparison. Surfaces covered with a monolayer of stearic acid molecules were scratched by a glass lens covered with a layer of diamond particles. Unidirectional scratches were made at 20-30 nm depth. The reaction products were monitored by a grazing angle FTIR capable of detecting the spectrum of a monolayer. The spectrum was then compared with the spectrum from a thermally heated case and a rubbed case. Results suggest that such scratching indeed produces similar reaction products.     

Origin and early evolution of vertebrate skeletonization

Data from living and extinct faunas of primitive vertebrates imply very different scenarios for the origin and evolution of the dermal and oral skeletal developmental system. A direct reading of the evolutionary relationships of living primitive vertebrates implies that the dermal scales, teeth, and jaws arose synchronously with a cohort of other characters that could be considered unique to jawed vertebrates: the dermoskeleton is primitively composed of numerous scales, each derived from an individual dental papilla; teeth are primitively patterned such that they are replaced in a classical conveyor-belt system. The paleontological record provides a unique but complementary perspective in that: 1) the organisms in which the skeletal system evolved are extinct and we have no recourse but to fossils if we aim to address this problem; 2) extinct organisms can be classified among, and in the same way as, living relatives; 3) a holistic approach to the incorporation of all data provides a more complete perspective on early vertebrate evolution. This combined approach is of no greater significance than in dealing with the origin of the skeleton and, combined with recent discoveries and new phylogenetic analyses, we have been able to test and reject existing hypotheses for the origin of the skeleton and erect a new model in their place.     

并联机器的起源和发展

目前，并联机器的发展已经从最初的实验原型样机走向实用化和商品化阶段。本文首先回顾了并联机器的起源，并阐述了其主要特点；然后探讨了并联机器的研究现状和存在的主要问题；最后介绍了清华大学在并联机器实用化研究中的主要进展。     

语义网的起源与发展

对语义网进行了系列综述,在分析语义网的起源、功能的基础上,与万维网进行了利弊比较,分析了语义网研究现状和语义网应用领域,对其今后的发展前景进行了展望.     

盘式制动器尖叫声起因

在制动器噪音研究领域已被工程师们和科学家们普遍公认,盘式制动器的尖叫声起因于因摩擦力导致自激振动造成不稳定性,自激系统当时发生振荡,达到极限周波.Papp等在2002年基于一个十分简单的模型阐述了摩擦力实际工作(即尖叫声的激励)的先决条件.本文作者为激励机理起因的研究采用-多自由度系统,用观测的衬片上的平均摩擦力功率和典型稳定分析相比较,基于这些理论研究开发了一测量技术探测抑制尖叫声的参量的范围(例如,对制动压力和相当的尖叫频率).     

From theory to therapy: implications from an in vitro model of ramified microglia

Microglia are the principal immune cells in the central nervous system (CNS), characterized by a highly specific morphology and unusual antigenic phenotype. An increasing number of studies have focused on the role of microglia in the pathogenesis of neurodegenerative diseases. To elucidate the function of microglial cells under several neuropathological conditions, we have studied and established a cell culture model that allows us to cultivate microglial cells in their inactive, resting (ramified) phenotype. In the first part of this work, we describe the interaction of microglia cells with their epithelial (astrocytic) microenvironment. The second part reviews experiments with microglia cell cultures to elucidate underlying signalling pathways and summarizes recent advances of our knowledge in microglial molecular pathways that may ultimately lead to neurodegeneration.     

汾西县扁桃产地的鼠类及鼠害防治初探

汾西县现有扁桃林1 000 hm2,近年鼠害严重,2014年邢家要乡与和平镇等地扁桃果实危害率达到50%~90%,佃坪乡扁桃林树体根系损害率达到50%以上,造成25%树体死亡,当地急需科学的灭鼠技术。笔者经2015年6月调查,查明当地害鼠4科10种,鼠密度达到11.33%,超过鼠害控制技术规程规定控制指标近4倍。根据调查结果,结合以往果树地鼠害防控经验和方法,将春、夏、秋、冬四季灭鼠的利弊和方法做了分析研究,并介绍了适合当地采用的人工灭鼠、器械灭鼠和毒饵灭鼠等鼠害防治方法。     

钢中非金属夹杂物来源分析

从外来夹杂物与内生夹杂物两个方面对非金属夹杂物来源进行分析,考察钢水中的全氧含量及钢包使用次数对夹杂物数量的影响。统计结果表明,现阶段精炼钢水中wT[O]稳定在25＆#215;10-6以内,而随着钢包使用次数的增加,钢中夹杂物数量也呈增加趋势。     

浅析物联网与动物源性食品污染控制

我国的动物源性食品安全控制体系比发达国家起步较晚,在生产、加工、流通等环节中食品安全问题比较突出,建立一个确保人们身体健康,促进食品工业发展的食品质量安全体系,具有重大意义。大数据时代的到来,物联网技术的发展,给动物源性产品污染控制提供了一个新的解决途径。     

Origin and significance of the SEM cathodoluminescence from zircon

In geochronological investigations, zircons are used frequently as a geological clock because of the small amounts of radioactive U isotopes and their decay products, e.g. Pb, incorporated into the crystal structure. However, the U or Pb concentration of zircon is not only dependent on the radioactive decay. One factor is the presence of old, inherited zircon cores in younger igneous zircons. This polyphase structure often cannot be recognized by conventional imaging methods, such as light microscopy. Dating such zircons, can therefore lead to ambiguous age results. However, zircons can be selected for dating purposes using cathodoluminescence (CL) in the scanning electron microscope. It is shown that zircon phases of different ages can be identified by their specific CL properties. Moreover, conclusions on the origin and on the development of the inherited phases can be drawn by comparison with detrital zircons. The zircon CL is formed by the superpostion of several broad bands. The shape of the spectra is dependent on the zircon genesis. By fitting the spectra with Gaussian curves, the individual CL bands can be separated. Using this methodology, it is possible to trace back the essential parts of the zircon CL to a superpostion of the quartz and zirconia (ZrO₂) CL. In addition, CL phenomena due to dysprosium impurities can be separated from intrinsic zircon CL properties.     

机械动力:工业革命的本源

工业革命是促进人类社会进步的主要经济动力。工业革命是一个渐进提升的过程,人类至今经历了多少次工业革命,社会上有多种说法。美国人里夫金的第三次工业革命论,燃起人们对工业革命的新议论。但是,归根结底工业革命还是来源于工业生产动力的创新。     

Origin of Friction in Running-in Sliding Wear of Nitride Coatings

To investigate the origin of running-in friction in unlubricated sliding wear, a magnetron sputtered multilayer coating TiAlN/VN was tested on a ball-on-disc tribometer for a series of sliding durations from 10 to 1000 cycles, followed by careful observation of the obtained worn surfaces using an field-emission gun scanning electron microscope. Three steps of friction variation were found: (1) prior to wear particle generation, low initial friction coefficient was around 0.2–0.25 purely attributed to the asperity contact; (2) then it increased steeply to a range of 0.4–0.5 in the first 100 cycles following the generation, breaking and agglomeration of wear particles, and in particular the scaling-up of fish-scale-like tribofilm; (3) eventually it approached to a steady-state value around 0.5 when the friction was governed by the viscous shearing of the tribofilm. It is concluded that, under unlubricated sliding wear, the friction behaviour of transition metal nitride hard coating is dominated by the viscous shearing of tribofilm adhesively bonding to the parent nitride coating.     

Phagocytic properties of microglia in vitro: implications for a role in multiple sclerosis and EAE.

The microglial cell, after many years of neglect, has become recognized as the sole representative cell of the immune system that resides in the normal central nervous system. While normally dormant, microglia can be activated by secretory substances or signals associated with disease or injury, and becomes a phagocytic cell, which also produces its own injurious molecules. In the activating process, its morphology is changed from a resting process-bearing cell, into a rounded amoebic form, and displays new or increased amounts of functional markers, such as receptors and Class I and Class II MHC molecules. Microglia prepared from newborn mice or rats for tissue culture are already activated, and can be used for studies of their phagocytic properties. Although they can phagocytize foreign substances, their uptake and metabolism of myelin are emphasized here, in keeping with their role in demyelinating diseases. A number of receptors have been implicated and appear to be important in the attachment to, and ingestion of, myelin particles in vitro, including the Fc, complement, macrophage scavenger, and the Galectin-3/MAC-2 receptors, although the alpha2-macroglobulin/low-density lipoprotein receptor and mannose receptors have also been suggested as participants in myelin phagocytosis. Certain cytokines and adhesion molecules also regulate the phagocytic activity of microglia. Comparative in vitro studies of phagocytosis by peritoneal macrophages and microglia have shown that the two kinds of cells respond differently to regulatory molecules, and it is concluded that they have different innate properties. The role of microglia in the demyelinative diseases experimental autoimmune encephalomyelitis and multiple sclerosis is emphasized here, and the possible means of intervention in the process leading to myelin destruction is discussed. Published 2001 Wiley-Liss, Inc.     

也谈营销理念的起源 发展和创新

通过追溯营销产生的历史、简要论述了营销理念的发展和创新。概括了现代营销理念的六个特征,提出了市场调查、市场研发、实现产品价值等各个方面具体操作方法。肯定了营销是研究经营与销售活动的科学。