Freeze-fracture and immunomorphological analysis of spiral ganglion cells

Freeze-fracture analysis of adult spiral ganglion cells of CBA/CBA mice revealed two types of membrane specializations. Most cells (type I) had a smooth surface and were surrounded by Schwann cells. Type II spiral ganglion cells showed numerous membrane specializations with well-delineated indentations similar to those previously found on hair cells adjacent to afferent and efferent nerve endings. Immunomorphological analysis (using well-defined monoclonal antibodies directed against different subclasses of intermediate filament proteins) revealed a unique co-expression of neurofilaments, vimentin and cytokeratins in spiral ganglion cells of 8-to 22-week human fetuses.     

Morphological observations of small granule-containing (Chromaffin) cells in the celiac ganglion of the guinea pig,with emphasis on cell contacts

Utilizing electron microscopic observation, several contacts between small, granule-containing cells (SGC) and postganglionic neurons (PGN) in the celiac ganglion of the guinea pig have been observed. A SGC in very close association with a PGN was seen to receive a distinct synaptic contact that contained many vesicles with dense cores. This contact was morphologically unlike cholinergic synapses previously reported on chromaffin cells. Because the SGC and PGN were clearly separated by a thin rim of satellite cell cytoplasm mutual to both cells, it is not known how or if the SGC would possibly exert a synaptic or paracrine effect on the PGN. Also, intraganglion SGC existed as large well-vascularized islands within the celiac ganglion. These intraganlion clusters sometimes contained more than 50 cells and perhaps could be considered to function as localized neuroendocrine components within the ganglion by secreting granule products into the nearby blood vessels for local or distant effects, although this certainly is not known. This work reports a unique synaptic ending upon a single-occurring SGC, which, in turn, closely approximates a ganglion neuron in a soma-somatic relationship. In addition, a very close association (but no actual contact) was observed between granule-containing processes, presumably emanating from the intraganglion clusters, and PGN. Whatever the function of ganglionic SGC may be, the exact relationship between SGC and PGN presumably would be of great interest and potential importance. © 1994 Wiley-Liss, Inc.     

量产螺旋锥齿轮清洗机的设计

汽车螺旋锥齿轮是大批量生产的产品,其清洗装备是影响专业化大批量生产的瓶颈,文章介绍了针对这一问题而设计制造的紊流清先机的结构与原理,该机较好地解决了螺旋锥齿轮的清洗问题。     

Distribution of GABA and glycine receptors on bipolar and ganglion cells in the mammalian retina

The amino acids GABA and glycine mediate synaptic transmission via specific neurotransmitter receptors. Molecular cloning studies have shown that there is a great diversity of GABA and glycine receptors. In the present article, the distribution of GABA and glycine receptors on identified bipolar and ganglion cell types in the mammalian retina is reviewed. Immunofluorescence obtained with antibodies against GABA and glycine receptors is punctate. Electron microscopy shows that the puncta represent a cluster of receptors at synaptic sites. Bipolar cell types were identified with immunohistochemical markers. Double immunofluorescence with subunit-specific antibodies was used to analyze the distribution of receptor clusters on bipolar axon terminals. The OFF cone bipolar cells seem to be dominated by glycinergic input, whereas the ON cone bipolar and rod bipolar cells are dominated by GABAergic input. Ganglion cells were intracellularly injected with Neurobiotin, visualized with Streptavidin coupled to FITC, and subsequently stained with subunit specific antibodies. The distribution and density of receptor clusters containing the alpha1 subunit of the GABA(A) receptor and the alpha1 subunit of the glycine receptor, respectively, were analyzed on midget and parasol cells in the marmoset (a New World monkey). Both GABA(A) and glycine receptors are distributed uniformly along the dendrites of ON and OFF types of parasol and midget ganglion cells, indicating that functional differences between these subtypes of ganglion cells are not determined by GABA or glycinergic input.     

Trigeminal ganglion morphology in human fetus

The morphology of the trigeminal ganglion in human fetus was investigated by means of the tract‐tracing method using the lipophilic dye DiI‐C18‐(3) (1,1′‐double octadecane 3,3,3′3′‐tetramethyl indole carbonyl cyanine‐perchlorate), hematoxylin–eosin (HE) stain, and three‐dimensional computer reconstruction models. The trigeminal ganglion was flat in the dorsoventral direction, and DiI staining revealed that the trigeminal ganglion cells were somatotopically distributed in the ganglion in a way that reflected the mediolateral order of the three branches. Ganglion cells of the ophthalmic nerve were distributed in the anteromedial part of the trigeminal ganglion, those of the mandibular nerve were in the posterolateral part, and those of the maxillary nerve were localized in the intermediate part. DiI labeled both ganglion cells and nerve fibers in the trigeminal ganglion; the ganglion cells varied in size and appeared as round‐ or oval‐shaped, the neurites connected the cell soma, and some bipolar neurons were also observed. The number of embryonic trigeminal ganglion cells did not significantly change with gestational age, but the cell diameter, area, and perimeter significantly increased. The motor root leaves the pons, runs along the sensory root, passes the ventral surface of the ganglion, and finally runs together with the mandibular nerve. The findings reported here elucidate the morphology, development, and somatotopic organization of the trigeminal ganglion and reveal the trigeminal nerve motor root pathway along the trigeminal ganglion and mandibular nerve in the human fetus. Microsc. Res. Tech. 76:598–605, 2013. © 2013 Wiley Periodicals, Inc.     

大型齿轮在机检测螺旋线偏差信号的采集和分析

针对直径大于2.5m的大型齿轮的螺旋线偏差开展了在机测量研究.在分析其测量原理与方法的基础上,进行检测信号的采集与分析,并通过测量试验研究分析其误差影响因素及测量过程存在的问题.     

肾上腺节细胞神经瘤的多排螺旋CT诊断价值

目的:探讨肾上腺节细胞神经瘤的螺旋CT表现及鉴别诊断。方法:回顾分析9例经手术病理证实的肾上腺节细胞神经瘤的螺旋CT扫描资料,重点分析其强化特点。结果:9例肾上腺节细胞神经瘤6例位于右侧,3例位于左侧。病灶呈圆形或椭圆形,边界清晰。9例患者CT扫描可见肿物为实性7例,病灶密度均匀,2例病灶内伴有钙化。增强扫描后8例病灶呈进行性均匀强化。结论:肾上腺节细胞神经瘤CT影像表现具有一定的特征性,多排螺旋CT不仅能作出正确定位并且能比较准确进行定性诊断。CT平扫及增强扫描是本病手术之前的主要诊断依据。     

"非零"传动弧齿锥齿轮CAD参数化绘图方法

介绍了“非零”传动弧齿锥齿轮CAD图形系统参数化设计过程中的若干计算机绘图功能的实现方法和技巧,讨论了该参数化绘图软件的特点及优点。经多次试用表明,这些方法正确、实用,可供弧齿锥齿轮CAD二次开发人员参考。     

Visualizing soft tissue in the mammalian cochlea with coherent hard X-rays

This paper concerns an important aspect of current developments in medical and biological imaging: the possibility for imaging soft tissue at relatively high resolution in the micrometer range or better, without tedious and/or entirely destructive sample preparation. Structures with low absorption contrast have been visualized using in-line phase contrast imaging. The experiments have been performed at the Advanced Photon Source, a third generation source of synchrotron radiation. The source provides highly coherent X-ray radiation with high photon flux (>10(14) photons/s) at high photon energies (5-70 keV). Thick gerbil cochlear slices have been imaged and were compared with those obtained by light microscopy. Furthermore, intact gerbil cochleae have been imaged to identify the soft tissue structures involved in the hearing process. The present experimental approach was essential for visualizing the inner ear structures involved in the hearing process in an intact cochlea.     

弧齿锥齿轮的三维模型设计

采用运动学方法和齿轮啮合原理推导了弧齿锥齿轮的齿面方程,再用MATLAB软件编程采集齿面上点的信息生成数据文件,然后把数据导入三维造型软件CATIA中构造齿轮的轮齿曲面,最终实现了弧齿锥齿轮的三维模型.     

Intrinsic neurons in the mammalian ovary

Mammalian ovarian function is under endocrine and neural control. Although the extrinsic innervation of the ovary has been implicated in the control of both ovarian development and mature function, it is now clear that, from rats to humans, the ovary is endowed with a network of intrinsic neurons displaying diverse chemical phenotypes. This article describes the presence of these intrinsic neurons in the ovary of different mammalian species, and discusses the possible functions that they may have in the regulation of ovarian physiology.     

Influence of tooth modifications on tooth contact in face-hobbed spiral bevel gears

In this study the influence of tooth modifications induced by machine tool setting and head-cutter profile variations on tooth contact characteristics in face-hobbed spiral bevel gears is investigated. The concept of face-hobbed spiral bevel gear generation by an imaginary generating crown gear is applied. The modifications of tooth surfaces are introduced into the teeth of both members. The lengthwise crowning of teeth is achieved by applying a slightly bigger radius of lengthwise tooth flank curvature of the crown gear generating the concave side of pinion/gear tooth-surfaces, and by the variation of machine tool settings in the generation of pinion/gear teeth. The ease-off in the tooth height direction of meshing tooth surfaces is achieved by applying a head-cutter whose profile consists of two circular arcs, instead of a straight-line. The method of tooth contact analysis applied determines the path of contact, the potential contact lines, the separations along these lines, and the transmission errors. A computer program implements the method. By using this program the influence of the variation of machine tool settings and of head-cutter geometry on tooth contact is investigated and discussed.     

弧齿锥齿轮齿面接触区的边缘检测技术

使用数字图像处理技术实现弧齿锥齿轮齿面接触区的检测.根据眼识别特性,按色差对齿轮齿面接触区进行灰度变换;采用Robot边缘检测算法进行边缘提取,得到较好的接触区轮廓,为齿轮检测系统的三维坐标计算提供前提条件.     

基于AutoCAD2002螺旋线的自动绘制程序

利用VBA开发了应用于AutoCAD2002环境下的对数螺旋线自动绘制的程序，解决了工程中常用曲线的迅速、准确绘制问题。     

Investigation of tribological behaviors of annular rings with spiral groove

A series of experiments is conducted to study the tribological behavior of spiral groove thrust bearings. The experimental system consists of a nominally flat upper ring mating with a stationary spiral groove lower ring in fully flooded lubrication environment. Spiral groove thrust bearings with different spiral angles subjected to different loads and speeds are tested. Stribeck-like curves are obtained and their characteristics are discussed. Transition points from mixed to hydrodynamic lubrication are experimentally established. In addition, a theoretical model is developed to gain further insight into the frictional characteristics of spiral grooves in both the hydrodynamic regime and the mixed lubrication regime.     

螺旋锥齿轮传动强度的计算

为了使高强度齿轮的齿面在传动过程中具有更高的可靠性,论述了弧齿锥齿轮传动预强度的计算方法,这种方法是基于两个椭圆双曲体接触问题赫兹解提出的,并且在设计中充分考虑了齿轮接触面当量曲率大小和齿面廓形局部接触及纵向局部接触等多个系数.通过计算表明,无论是在较好的磨合性表面或较差的磨合性表面条件下,计算的结果都能很好地贴近实际.该计算方法避免了传统计算方法中仅考虑齿面廓形接触的局限性,能广泛应用于航空工业中,即应用于高硬度表面齿轮传动中.     

螺旋叶片锥辊辗轧机喂料装置的设计

无轴螺旋叶片的应用越来越广泛，这里从结构上介绍了厚螺旋叶片的锥辊辗轧机喂料装置的核心设计，该装置较好地满足了生产的需要。     

弧齿锥齿轮固有振动特性分析

弧齿锥齿轮主要用于高速、重载的场合,有可能在额定转速内发生强烈的共振,振动应力急剧增大,致使齿轮过早引起疲劳破坏.运用APDL语言自主开发的弧齿锥齿轮建模程序建立了包含齿轮完整结构的有限元模型,计算了不同腹板厚度下的五个弧齿锥齿轮的固有特性,归纳了几种基本齿轮低阶振型种类.结果表明随腹板厚度的增加弧齿锥齿轮的固有频率有所增大,对变形和振动应力的影响效果则与振型有关.     

Ultrastructural correlates of meiotic maturation in mammalian oocytes

Immature mammalian oocytes reside in ovarian follicles with junctionally coupled granulosa cells. When released from a currently undefined meiotic arresting influence, these oocytes resume meiosis to progress from late diplotene (germinal vesicle stage) through the first meiotic division to metaphase II. Oocytes remain at metaphase II until fertilization activates them to complete meiosis. This review summarizes ultrastructural events that occur during meiotic maturation in mammals. Developmental correlates that promise a clearer understanding of regulatory mechanisms operating to control maturation are emphasized. By use of TEM of thin sections, freeze-fracture analysis, and replicated oocyte cortical patches, we demonstrate stage-specific changes in the oocyte nucleus, reorganization of cytoplasmic organelles, correlations between oocyte maturational commitment and the junctional integrity of associated granulosa cells, and definition of the components comprising the oocyte cortical cytoplasm.     

High-resolution X-ray tomography of the human inner ear: synchrotron radiation-based study of nerve fibre bundles, membranes and ganglion cells

The combination of osmium tetroxide staining and high-resolution tomographic imaging using monochromatic X rays allows visualizing cellular structures of the human inner ear, that is, the organ of Corti, the stria vascularis and further soft tissues of the membranous labyrinth, in three-dimensional space with isotropic micrometre resolution. This approach permits to follow the course of nerve fibre bundles in a major part of the specimen and reveals the detailed three-dimensional arrangement of individual ganglion cells with distinct nuclei by means of X-ray tomography for the first time. The non-destructive neuron cell counting in a selected volume of 125 μm × 800 μm × 600 μm = 0.06 mm³ gives rise to the estimate that 2000 ganglion cells are present along 1 mm organ of Corti.