大白鼠脑室模型的建立及其表面构造的观察

脑室系统乃脑脊髓液的通道。我们以Meercox及methyl methacrylate由第四脑室的正中孔或脑下垂体的柄部注入脑室,待其硬化后以20％NaOH将其软组织溶去而成功的得到大白鼠脑室的缔造模型,由其立体的架构更能有效,具体的明了脑室的构造。由模型的观察吾人发现有下列各点乃大白鼠与人类者相异处。 1.侧脑室之前角与第三脑室的速接乃起源于其外侧缘,而有别于人类的内侧缘。 2.由于丘脑(thalanues)间的速接处(interventicular mass)很大而使大白鼠的第三脑室近环状(如图一)。     

大鼠侧脑室及其脉络丛室管膜上皮的超微结构观察

采用扫描和透射电子显微镜研究大鼠侧脑室及其脉络丛室管膜上皮的超微结构特征，并探讨其功能。扫描电镜观察结果：侧脑室壁室管膜上皮细胞游离端呈不规则多边形，可见纤毛及微绒毛，偶见分泌泡，脉络丛上皮细胞游离端微绒毛及分泌泡丰富，纤毛光见，可见、丛上细胞”。透射电镜观察发现，侧脑室壁及脉络丛上皮均由单层立方上皮组成，但二类上皮细胞的超微结构明显有别，室管膜上皮表面可见纤毛及微绒毛，分泌泡少见，脉络丛上皮游离端微绒毛丰富，常吻合成迷路样网，微绒毛的顶端膨大，形成微顶浆分泌小泡，胞浆内细胞器丰富，大鼠侧脑室壁及脉络丛上皮超微结构的差异反映二者功能的不同，本研究认为侧脑室脑脊液分泌的主要部位是脉络丛，其分泌的方式除脉络丛上皮细胞的主动运输功能外，可能微顶浆分泌法是侧脑室脑脊液形成的主要方式。     

小鼠骨髓基质细胞标志酶的电镜细胞化学研究

本文应用电镜酶细胞化学技术在电镜下观察正常小鼠骨髓基质细胞标志酶的特征。在小鼠骨髓基质中除静脉窦外,还有网状细胞和巨噬细胞。小鼠骨髓酶细胞化学反应表明,碱性磷酸酶(ALP)是窦周和窦间网状细胞的良好标志酶,显示特异性细胞膜阳性反应(图1、2);而酸性磷酸酶(ACP)和酸性非特异性酯酶(ANAE)则是巨噬细胞的标志酶,其胞     

胃癌印戒细胞超微结构酶细胞化学研究：五种细胞器标志酶的电镜观察

胃印戒细胞癌多见于30岁以下的女性,其侵袭力强,转移率高,这种生物学行为的发生机理日益受到关注。但从酶学特别是对多种细胞器标志酶进行超微结构水平的研究,文献中未见报告。本文应用酶细胞化学技术对胃癌印戒细胞五种细胞器标志酶(碱性磷酸酶AKPaee,酸性磷酸酶Acpace,葡萄糖-6-磷酸酶G6Pase,焦磷酸硫胺素酶TPPaee和细胞色素氧化酶Coaee)进行了细胞和超微结构水平的定位观察,并以正常胃粘膜作为对照,探讨了胃癌印戒细胞五种细胞器标志酶的分布特点及其与生物学行为间的关系。结果发现:正常胃粘膜上皮细胞AKPace均阴性;Acpase活性以主细胞为最强,旦分布于自噬及分泌溶酶体中;胃粘膜上皮细胞的核周间隙和粗面内质网(RER)G6paee均阳性,主细胞富于RER     

大鼠坐骨神经再生过程中的神经元轴突自噬作用

目的：探讨大鼠坐骨神经变性轴突清除中的自噬作用。方法：横切大鼠坐骨神经制作wallerian变性模型,造模后不同时间点取远断端组织行电镜结构观察和酸性磷酸酶(AcPase)活性检测。结果：坐骨神经横切后轴突发生变性,主要变化为术后第5h～2d轴质肿胀,轴突与髓鞘分离,术后第4d轴质浓缩,轴突与髓鞘完全分离形成游离轴突体。术后初期变性轴突主要形成大小不等的空泡,后期轴突与髓鞘完全分离并形成较大的游离轴突体,轴突体外包一层轴突膜是神经元细胞膜的延续,轴突体轴质浓缩,含大量各级自噬泡和纵横交错的神经丝、微管和微丝。经酸性磷酸酶(AcPase)染色证实自噬泡均呈AcPase阳性,第7d后轴突体被降解吸收,形成的空腔内偶见巨噬细胞。结论：大鼠坐骨神经再生过程中变性轴突的清除主要靠轴突自身的自噬和施万细胞吞噬机制,而巨噬细胞只起辅助作用。     

大鼠第三脑室室管膜上巨噬细胞迁移过程的电镜观察

对第三脑室室管膜上巨噬细胞迁移过程进行不同时相的扫描电镜观察,结合透射电镜分析其细胞类型及相应功能。结果示第三脑室内存在室管膜上巨噬细胞,此类细胞胞体呈卵圆形或椭圆形,伸出多个舌状和指状伪足,其迁移的全过程是首先在室管膜表面形成穹窿样隆起,继而推开室管膜上皮细胞间隙,露出胞体,继续向外游走,最后完全游离在脑室腔内。透射电镜下该细胞呈长卵圆形,核大,异染色质多,细胞器较少,具有单核吞噬细胞的形态特征。本文在超微结构水平清晰地观察到第三脑室室管膜上巨噬细胞迁移过程的不同时相,并为进一步探讨其功能提供了超微形态学基础。     

边缘学科分支最新动向

TN一051 2004041216低频调制磁场对脑电节律的影响机理/王学民,(2{郭明霞,马舜尧,王明时(天津大学)11天津大学学报,一2004,37(3)一278一281神经细胞CaZ十内流及脑内5一HT、NE、DA等神经递质的变化影响了神经细胞放电速率,从而影响脑电节律.为揭示低频调制磁场对脑电节律产生影响的微观作用机理,检测了Wistar大鼠脑内神经递质的释放,电镜下观察了其神经突触形态的变化.实验结果显示,低频调制磁场作用引起大鼠脑内去甲肾上腺素(NE)、多巴胺(DA)、5一轻色胺(5一HT)释放显著增加(P<0 .05),并观察到大鼠神经细胞内钙颗粒及释放神经递质的…     

人毛滴虫高尔基体和溶酶体的细胞化学研究

人毛滴虫是寄生于人或灵长目动物肠道的常见原虫,具有真核细胞的一般结构。高尔基复合体发育较好,U-Pb-Cu选择性浸染法显示其机能旺盛时,扁平膜囊可多达十二层(图1),GERL呈较强的ACPase(图5)和CMPase(图8)活性,成熟面扁平膜囊为TPPase阳性(图2),而中间扁平膜囊显示有明显的NADPase反应(图4)。以上结果表明这种低等的原生动物具有与较高等哺乳动物细胞相似的高尔基复合体结构和功能。     

脑室内注射链脲佐菌素大鼠海马神经元和突触的超微结构异常

目的:观察侧脑室内重复注射小剂量链脲佐菌素(streptozocin,STZ)阿尔茨海默氏病(alzheimer disease,AD)模型大鼠的学习记忆和海马神经元的超微结构改变.方法:采用Morris水迷宫进行行为学测试;取海马CA1区组织制成超薄切片,透射电镜观察.结果:模型组大鼠Morris水迷宫平均游泳时间及平均游泳距离明显延长.海马CA1区神经元出现程度不等的退行性变.细胞核形态不规则.部分核内染色质浓集;胞浆内脂褐素颗粒增多,高尔基囊泡扩张.严重者出现早期细胞凋亡改变.神经毡内可见有髓鞘轴突胞质内脂褐素颗粒明显增多,突触结构异常,突触小泡聚集增多,分布无序.突触后膜胞质面上的致密斑不规则增厚,或断断续续不完整.结论:侧脑室内注射STZ可引起大鼠海马神经元和突触的超微结构病变,导致大鼠学习记忆能力减退.     

高血压大鼠第四脑室外侧隐窝室管膜细胞超微结构变化的电镜观察

目的:观察一氧化氮(NO)缺乏型高血压大鼠,第四脑室外侧隐窝室管膜细胞及其分泌状态的超微结构变化.方法:30只健康雄性Wistar大鼠,其中20只予以一氧化氮合酶抑制剂左旋硝基精氨酸(L-NNA) 15 mg/d,腹腔注射,复制高血压动物模型;10只予以0.9%氯化钠2 mL/d腹腔注射作为对照.对照组、用药2周组和用...     

微波介电加热合成半导体CuS纳米粒子

在2％的硬脂酸的丁醇溶液中,以硝酸铜和硫代乙酰胺为源村料,通过微波介电加热合成了CuS半导体纳米粒子,并用XRD、TEM进行了表征。     

Polyol Synthesis of Nano-Bi2Te3

In this work, a simple and easily scalable wet-chemical synthesis of nanoscale Bi₂Te₃ has been developed. Bi₂Te₃ nanoparticles were produced via a polyol method by reaction of Na₂Te in solution with a selection of bismuth(III) salts in boiling ethylene glycol. Depending on the reaction temperature and time, particles with size ranging between 20 nm and 400 nm could be obtained in high yield. Phase-pure products could be obtained under refluxing conditions. We show the necessity of a certain reaction time or temperature for complete reaction of the compounds, and the dependence on the type of bismuth salt and the reactant quantity based on the tellurium contamination in the Bi₂Te₃ products. Nuclear magnetic resonance investigations suggest possible mechanisms for the formation of the Bi₂Te₃ particles. The composition, particle size, and morphology of the synthesized products were investigated by powder x-ray diffraction, energy-dispersive x-ray spectroscopy, transmission electron microscopy, and scanning electron microscopy. The resulting particles demonstrated high purity.     

Synthesis and characterization of lead selenide nanostructure through simple sonochemical method in the presence of novel precursor

In the present study, PbSe nanostructures have been synthesized by using [bis(salicylate)lead(II)]; [Pb(Hsal)₂] as lead precursor in the presence of sonochemical method in aqueous solution. Besides, the effects of reaction time, ultrasonic power, and surfactant on the morphology and particle size of products were studied by SEM images. It was found out that the size and morphology of the products were greatly influenced by these parameters. The XRD studies indicated the production of pure cubic PbSe nanostructures could only happen in the presence of ultrasonic radiation. The average diameter of the PbSe nanostructures was 12 nm. Products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) and EDX analysis.     

Fabrication of Mg（OH）2 Powders by Decomposition of Mg3N2 Powders

Mg（OH）2 powders were formed by the decomposition of Mg3N2 powders synthesized by a simple reaction of Mg with N Ha. X-ray diffraction（XRD）, Fourier transform infrared spectroscopy （FTIR）, and scanning electron microscopy（SEM） were used to study the structure, composition and morphology of the products. Mg （OH）2 nanowires with an average diameter about 300 nm-500 nm were found in these Mg（OH）2 powders.     

a-Fe_2O_3纳米棒的制备研究

采用压力–热晶法,制得棒状的前躯体后再在600℃焙烧8 h,成功地制得直径在20~40 nm,长度在300~500 nm之间,均匀分散、疏松多孔的六方结构的棒状Fe2O3纳米粒子,并用透射电子显微镜、电子衍射、X射线衍射等技术手段对样品进行了表征,考察了制备条件对产物粒径、形貌的影响。结果表明:初始铁盐浓度对产物粒径影响不明显,可以在较高初始浓度下制备Fe2O3纳米粒子;pH值、初始压力对粒子形貌和大小有一定的影响。     

Laser-induced direct etching of GaAs using chlorofluorocarbon (CFC) alternative gases

Non-ozone layer destructive chlorofluorocarbon (CFC) alternatives have been initially used for laser-induced thermochemical etching of GaAs. The CFC alternatives used here are CHClF₂ and C₂H₂F₄. Respective etching rates of 188 and 160 μm/s were achieved using CHC1F₂ and C₂H₂F₄ gases. Aspect ratios of 2.5 and 1.5 were achieved with a single laser scan for CHClF₂ and C₂H₂F₄, respectively. The presence of some reaction products deposited on the etched region was dependent on three variables: laser power, scan speed, and gas pressure. Chemical compositions of the reaction products were measured by Auger electron spectroscopy.     

Enzyme-histochemical demonstration of lymphatic vessels in the golden hamster periodontium: an attempt to reactivate the 5'-nucleotidase activity with Mg++ ion supply

Enzyme-histochemical demonstration of lymphatic vessels in the golden hamster periodontium was performed on cryostat sections using the 5'-nucleotidase (5'-Nase) staining method by light microscopy and backscattered electron imaging of scanning electron microscopy. The inhibition of the 5'-Nase activity by decalcification was cancelled by the Mg++ ion supply. The reaction products of 5'-Nase activity were produced on the lymphatic endothelial cells and the tubular structures of lymphatic vessels were seen as highlights by backscattered electron imaging. The invasion of 5'-Nase-positive lymphatic vessels into the alveolar bone from the periodontium was found in the present study.     

Novel two-dimensional lead sulfide quadrangular pyramid-aggregated arrays with self-supporting structure prepared at room temperature

Two dimensional (2D) self-supporting lead sulfide (PbS) arrays composed of ordered quadrangular nanopyramids were successfully fabricated through a convenient wet-chemical route at room temperature. The as-synthesized products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, UV–vis–NIR absorption and photoluminescence spectroscopy. The as-prepared highly ordered self-supporting superstructures are stable under ultrasonic conditions. A “template-mediated in situ growth” mechanism is proposed for the formation of 2D PbS superstructures. With the prolongation of reaction time, the morphology evolution of PbS is clearly observed, which could be changed from nanopyramid-aggregated arrays into nanocube-aggregated arrays at original position. The optical properties of PbS self-supporting superstructures are investigated in detail.     

Preparation and Transport Properties of Bi2O2Se Single Crystals

Bi₂O₂Se single crystals were grown by a gas-phase transport reaction with a temperature gradient. X-ray diffraction revealed that the products crystallized in a tetragonal-type lattice with lattice parameters a?=?0.38866?nm and c?=?1.22001?nm. The samples were characterized by measuring the electrical conductivity, Hall coefficient, and Seebeck coefficient as functions of temperature between 80?K and 470?K. The obtained experimental data allowed us to calculate the reduced Fermi level, provided that the single-valley parabolic model applied. The corresponding value of the electron effective mass proved to be m _ef????0.29. Free electron mobility is governed by the scattering of carriers by acoustic phonons.