不同抗冷级别的棉苗在低温处理后叶片细胞超微结构的变化

本实验以分属早熟和晚熟两类不同抗冷级别的３个棉花品种为材料，将其幼苗经４℃低温处理１２ｈ，用透电子显微镜观察叶片细胞超微结构的变化。结果表明：低温处理后早熟品种的叶绿体和液泡没有明显的变化；而晚熟品种的叶绿体则发生变形重叠，液泡浓度加大，且出现了多层膜状结构。说明细胞结构的稳定性与棉花品种的抗冷性密切相关。     

阿齐霉素抗弓形虫作用的超微结构研究

弓形虫病是常见的人兽共患寄生虫病。孕期感染弓形虫会通过胎盘感染胎儿[1] 、导致畸胎、早产、流产和智力低下等不良结局。目前通常采用磺胺与乙胺嘧啶治疗 ,由于这类药对胎儿有不良副作用 ,故急需寻找高效低毒的抗虫药物。本实验对阿齐霉素抗弓形虫的作用进行了超微结构的研究。本实验采用猴肾细胞培养后感染猪弓形虫 NT株 ,并在感染弓形虫前后分别以 0 .1 μg/ ml、1 μg/ ml及 1 0 μg/ ml阿齐霉素作用于培养的猴肾细胞 ,同时设无药对照组 ,在 37℃、5 % CO2 中培养 2 4～ 48h后取细胞以 2 .5 %戊二醛固定 ,分别按常规制备透射电镜和…     

葫芦科花粉外壁超微结构的观察

本文利用扫描电镜对葫芦科植物中7个属的11种瓜菜类作物花粉外壁的超微形态进行了观察。根据表面纹饰特点可分为:刺状纹饰、网状纹饰、穴状玟饰和脑状纹饰。花粉形状有球形、扁球形和长球形;除西瓜、苦瓜、丝瓜外,均为等级花粉;其对称性有完全对称、左右对称和辐射对称;萌发器官分为有孔盖萌发孔、无孔盖萌发孔、细长的萌发沟和略宽的萌发沟孔。其中较大的花粉大小为39.64×37.08微米,较小的花粉大小为13.22×15.55微米。     

毛细胞白血病的超微结构观察

毛细胞白血病 ( HCL)是一种少见类型的白血病 ,发病率约占白血病的 2 % ,而儿童患者更少 ,临床统计发病年龄平均为 5 0岁。自 1 95 8年 Bouroncle等 [1]首先用透射电镜观察该病的血细胞后 ,电镜观察已成为研究和诊断该病的重要手段。毛细胞在透射电镜下以胞浆呈现许多不规则突起为其特征。我们在观察一例儿童毛细胞白血病时 ,发现红细胞系细胞表面也不规则 ,有许多球拍状突起 ,现报道如下。材料与方法　患儿 ,男 ,1 2岁 ,临床骨髓片毛细胞占 91 % ,诊断为毛细胞白血病。取肝素抗凝的骨髓血细胞分层后 ,常规透射电镜制样 ,日立 H- 6 0 0型…     

McArdle病的超微结构观察

本文报道两例Ｖ型糖元沉积性肌病的肌活检超微形态改变，光镜下见肌纤维中呈现的ＰＡＳ染色阳性的颗粒状沉积物质，肌磷酸化酶染色阴性。电镜检查可区别为三种形态学改变：（一）肌膜下及肌原纤维间有多量游离糖颗粒沉积；（二）在完全破坏的纤维中，糖元颗粒聚集成圆球形和不规则形；（三）出现众多的空泡，其间见残存的细胞碎片和散在稀疏的糖元粒沉积。     

急性黄疸性肝炎的超微结构观察

肝是机体重要器官之一,肝细胞受损直接影响其代谢,合成,分泌和解毒等功能。急性黄疸性肝炎病程较短,病变较重,它不仅具有急性肝炎的症状,体征及化验的异常,且血清总胆红素超过3.0mg/d1时,明显发生黄疸。本文观察了7例急性黄疸性肝炎的材料,现将超微病变总结如下:观察结果:急性黄疸性肝炎低倍镜下改变为广泛的肝细胞变性、坏死。变性以胞浆疏松化和气球样变最为普遍,致使肝细胞排列紊乱肝窦受压变窄,肝细胞内有胆汁淤积,电镜下肝细胞水肿,图1,2胞质疏松,粗面内质网呈囊状扩张,且有不同程度的脱颗粒,滑面内质网也扩张成池,线粒体呈浓缩基质电子密度增高,嵴无法辨认,糖原颗粒减少。个别肝细胞膜破裂,细胞核模糊不清,核仁偏位(图1),或核固缩(图2),细胞核常染色质丰富(图3),肝细胞间及窦周隙内充满大量胶原纤维并形成致密的细胞壁(图2～3)。在汇管部有的淋巴细胞突起     

肝细胞凋亡的超微结构观察

通过对肝细胞凋亡动态变化过程的电镜观察,揭示细胞凋亡与肝脏疾病的关系。选择２８例肝脏病变标本及６例正常肝脏标本,应用透射电镜观察细胞凋亡的超微结构变化。结果显示肝细胞凋亡具有一般细胞凋亡的超微结构变化,又具有其特殊形态学特征。应用电镜手段进行细胞凋亡研究有助于从更深的层次对细胞凋亡的形态学的认识。肝细胞凋亡的动态平衡失调与肝脏疾病的发生发展有密切的关系。     

多发性肌炎的超微结构观察

应用电子显微镜对３５例多发性肌炎肌活检标本进行观察，见纤维有不同程度变性，坏死及再生。间质有炎细胞浸润，毛细血管基底膜增厚或形成复层，内皮细胞肿胀，部分内皮细胞及淋巴细胞胞质内发现管网状包含体。文中对本病的病因及发病机理进行了讨论。     

甲状腺乳头状癌的超微结构观察

对３０例甲状腺乳头状癌进行了详尽的超微结构观察与分析,通过与６例甲状腺滤泡癌和２０例甲状腺腺瘤的对比观察与分析,提出了甲状腺乳头状癌细胞的超微结构特征,主要表现为核大,分叶核,丰富的常染色质,极少的核膜下异染色质及突出的核仁等。电镜观察为乳头状癌的超微病理诊断提供了有力的依据。     

中枢神经细胞瘤的超微结构观察

应用光镜检查及免疫标记,对2例中枢神经细胞瘤进行电镜观察.结果显示,中枢神经细胞瘤在电镜下具有一定的结构特征：瘤细胞间可查见桥粒样结构;胞质内有神经分泌颗粒和哑铃状致密核心颗粒;胞突内有丰富的微管和囊泡状结构.在外科病理诊断中,中枢神经细胞瘤难以与少突胶质细胞瘤、透明细胞室管膜瘤等肿瘤鉴别.电镜检查对鉴别诊断有比较重要的意义.肿瘤细胞胞突内的微管和囊泡、胞质内的神经内分泌颗粒等超微结构与免疫组织化学标记一致,同时也提示肿瘤起源于神经元细胞.     

Use of a sulfur waste for biosynthesis of cadmium sulfide quantum dots with Fusarium oxysporum f. sp. lycopersici

After hydrodesulfurization of Mexican oil's sour acid gases, a sulfur toxic waste is recovered, we used it to synthesize cadmium sulfide quantum dots, which have been recently studied due to their optical (high photostability, high quantum yield and fluorescence) and catalytic properties. Increased demand of cadmium sulfide quantum dots has led to research of new synthesis methods that with higher yields, increased control over particle diameter, that produce hydrophilic quantum dots -as most of them are obtained in organic solvents- and that are environmentally friendly because most methods employ toxic materials or involve a high energy consumption. This study attempted to synthesize hydrophilic cadmium sulfide quantum dots using an environmentally friendly method with a fungus capable of transforming a dangerous waste into a high-value-added product. Mycelia of Fusarium oxysporum f. sp. lycopersici were incubated with 1 mM cadmium nitrate and 1% (w/v) sulfur waste at 30 °C for 24 h, then the biomass was separated through paper filtration. The filtrate became yellow indicating presence of extracellular cadmium sulfide quantum dots, as was confirmed by increased UV–vis absorption around 300 nm and fluorescence at 510 nm. The biomass of Fusarium oxysporum f. sp. lycopersici produced after 24 h, extracellular stable, hydrophilic and biocompatible cadmium sulfide quantum dots from a sulfur dangerous waste. Biosynthesized quantum dots were circular with diameter of 6.116±2.111 nm and had a wurtzite crystalline structure.     

两种对虾杆状病毒的超微结构比较及其超微细胞病理的观察

应用透射电和超薄切片技术,对长毛对虾和斑节对虾的杆状病毒病进行研究。在对虾幼体发育的糠虾期之前的各期虾苗未查到病毒,而在糠虾期之后各期的肝胰腺和中肠上皮细胞核中的均查到大量典型的病毒及其包涵体。两种对虾感染的病毒大小、形态相似, 同一种病毒,该病毒属杆状病毒科Ａ亚组。病毒颗粒呈杆状,多见单囊模,少数似见有两层囊膜,病毒颗粒单个散要廖质和包涵体基质中,由核心、衣壳和囊膜一部分组成,核衣壳大小约（３９     

Semiconductor-diode v.h.f. and u.h.f. noise sources

The v.h.f. and u.h.f. noise properties of silicon and gallium-arsenide diodes are discussed. A formula for calculating the noise output is given.     

Optimisation of sensitivity and dynamic range of i.f.l.f. active filters

It is pointed out that the multiple-feedback topology for highorder active filters recently introduced by Perry, here labelled inverse f.l.f. (i.f.l.f.) topology, has significantly better dynamicrange properties than the otherwise equivalent `follow-the-leader-feedback? (f.l.f.) structure. The procedure for optimising the signal-level capabilities and the sensitivity performance of i.f.l.f. circuits is presented.     

Estimating frequency-response function using periodic signals and the f.f.t.

A technique for estimating a frequency-response function using a periodic pseudorandom binary sequence which is compatible with the fast-Fourier-transform algorithm is presented. A method of synchronising the p.r.b.s. and the sampling for the f.f.t. using a single clock source and two binary counters is described. A simple check on the synchronisations and the identification of an 8th-order lowpass Butterworth filter is provided.     

Noise behaviour of the m.o.s.f.e.t. at v.h.f. and u.h.f.

The optimum noise figures of an m.o.s.f.e.t. at u.h.f. and at pinch-off are calculated using a simplified equivalent circuit. The noise parameters are also determined experimentally. Theory and experiment are shown to be in good agreement. Noise parameters of the m.o.s.f.e.t. for the frequency range 0.1?0.8 GHz are given.     

Threshold region of f.d.m./f.m. signals

Although many papers have been published concerning the analysis of the threshold region of f.m. signals, they are all incomplete. The present letter introduces a new analysis, in which the carrier is modulated by a Gaussian baseband signal, and gives important results which cannot be deduced from previous analyses.     

Noise calibrator for v.h.f. and u.h.f. field-strength-measuring receivers

A simple noise generator, based on a semiconductor diode of the Zener type and suitable for use in the frequency range 30?900 MHz, can be used to check both absolute gain and noise performance of sensitive receivers.     

Experimental study of the correlation of f.m. and l.f. noise in Gunn oscillators

Measurements of the correlation of l.f. noise current and frequency fluctuations of Gunn oscillations have been made at several frequencies from 0.1 to 50 kHz. It appears that correlation of the frequency-noise with the flicker-noise current component is very small, but that correlation with the generation-recombination noise component is important.     

Good performance i.f. and premodulation filters for simple f.s.k. system

Results are given of a realisable i.f. filter that appears to give the best compromise design for the major performance parameters of an f.s.k. system: signal/noise ratio, intersymbol interference and tolerances to frequency and timing offsets. These results are determined by a computer f.m.-simulator program, keeping all the components ideal except the filters. In addition, various premodulation filters have been investigated, in conjunction with the i.f. filter, in terms of system performance.