双氢青蒿素对骨肉瘤细胞143B影响的研究

目的：研究双氢青蒿素（Dihydroatemisinine,DHA）对人骨肉瘤细胞143B的影响及所导致的形态学变化。方法：采用人骨肉瘤143B细胞株,通过设置对照组和低浓度、中浓度、高浓度的DHA组,H．E染色观察Trandwell小室穿梭能力;划痕愈合实验观察迁移能力;Hoechst33258荧光染色检测细胞凋亡;MTT法检测细胞增殖抑制能力。结果：DHA表现出明显地抑制人骨肉瘤143B细胞的迁移、增殖以及促进凋亡（P〈0．05）,且伴随浓度的递增和时间的延长,抑制作用更明显。结论：DHA具有较强的抗入骨肉瘤作用,其机制可能与DHA诱导骨肉瘤细胞凋亡,并抑制其增殖有关。     

Role of mitochondria in the switch mechanism of the cell death mode from apoptosis to necrosis--studies on rho0 cells

Detailed mechanisms of the switch of the cell death mode from apoptosis to necrosis remain to be solved, although the intracellular level of ATP and that of free radicals have been postulated to be the major factors involved in the mechanisms. In the present study menadione (MEN)-induced cell injury processes were studied using rho0 cells derived from human osteosarcoma 143B cells and parental rho+ cells co-treated with inhibitors of electron transfer chain of mitochondria or oligomycin, an inhibitor of ATP synthesis. Treatment of rho+ cells with 100 microM MEN induced apoptosis, which reached the maximum at 6 h, and was followed by an abrupt decrease thereafter, while necrotic cells (NC) increased continuously when they were judged by Annexin V and PI double staining. On the other hand, MEN induced apoptotic and necrotic changes much faster in rho0 cells compared to rho+ cells. The frequency to find apoptotic cells (AP) in the former cells was distinctly smaller than that to find NC judged by Annexin V and PI double staining. Electron microscopically, a major population of rho0 cells treated with MEN for 6 h consisted of intermediate cells, and a small number of AP co-existed. At 9 h of the treatment intermediate cells were exclusively seen, and AP were hardly detected. When parental rho+ cells were treated with MEN in the presence of oligomycin or oligomycin plus antimycin A both apoptotic and necrotic changes of the cells were distinctly accelerated. The intracellular level of superoxide in rho0 cells continuously increased after the MEN treatment, whereas that of ATP remained distinctly low before and after the MEN treatment compared to that in rho+ cells. These data suggest that the intracellular level of superoxide may be a key factor controlling the switch from apoptosis to necrosis.     

洋葱根冠外缘细胞编程性死亡过程中的超微结构研究

洋葱根冠外缘细胞在发育过程中发生细胞编程性死亡。用透射电镜观察结果表明,根据冠中部细胞（1）代谢活跃,中部两侧细胞（Ⅱ）逐渐粘液化同时表现出逐渐的液泡化过程,边缘1－3层细胞（Ⅲ）则表现出类似动物细胞编程性死亡的典型超微结构特征,该染色质凝聚在核膜边缘,胞质及细胞器表现出一种自噬作用,同时发现在动物细胞编程性死亡中未报道的核突起现象。     

狼疮性肾炎近端小管上皮细胞凋亡的超微结构观察

系统性红斑狼疮是一种严重危害人类健康的常见疾病。最常累及的器官是肾脏，即狼疮性肾炎，近乎100%的患者贤脏有损害。近年来，随着细胞调亡理论的引入，人们对细胞凋亡在狼疮性肾炎发病机制中的作用有了不同程度的研究，认为狼疮性肾炎可能与细胞凋亡有关。本文应用透射电镜技术，对多例狼疮性肾炎病人的肾穿活检组织进行了观察，看到近端小管上皮细胞有凋亡发生。     

Ultrastructural organization of the blood lymphoid cells in hairy cell leukemia

The cytochemical, immunological, and ultrastructural peculiarities of the hairy-cell leukemia cells are studied. The hairy cells can be identified by characteristic of ultrastructure of organellae: numerous thin processes on the plasma membrane, large cytoplasmic area, well developed granular endoplasmic reticulum, numerous vesicules and electron dense granules, a well differentiated lobulated nucleus with a large nucleolus in which the granular component predominates.     

基底细胞上皮瘤细胞内黑素小体复合体形成的超微结构观察

应用透射电镜观察了21例基底细胞上皮瘤,结果显示基底细胞上皮瘤中有许多不同阶段的凋亡肿瘤细胞,部分被相邻肿瘤细胞吞噬,被吞噬消化的凋亡细胞中黑素小体的结构基本保持完整,而其他细胞器则失去正常结构。相邻肿瘤细胞对凋亡细胞的循环吞噬最终在肿瘤细胞内形成黑素小体复合体,这可能是黑素细胞向肿瘤细胞输入黑素小体的重要途径之一。     

Three-dimensional higher-order mode analysis of transition from waveguide to shielded dielectric image line

The transition from a rectangular waveguide to a shielded dielectric image line is analysed by means of a mode-matching technique. The analysis takes into account higher-order modes also beyond the cutoff frequency. The numerical results of this field-theory analysis are in good accordance with measurement, in contrast to the usual transmission-line theory approach.     

Packet mode in wireless networks: overview of transition to thirdgeneration

This article presents an overview of packet mode data transfer in cellular networks. Leading 2G+ cellular networks of GSM GPRS and IS-95B are introduced. The architecture and protocol layers in two leading third-generation cellular network proposals, cdma2000 and WCDMA, are presented. Mobile IP support in various cellular networks is discussed next. With efficient support of mobile IP in cellular networks, seamless integration of cellular networks with the Internet is expected to be reached at a rapid pace     

Analysis of transition of a deterministic self-oscillating microwave system to the chaotic generation mode

The results of an experiment on the development of a high-efficiency noise generator by transferring an avalanche-diode self-oscillator to the chaotic generation mode are presented. It is demonstrated that the noise level of such a generator exceeds by far the analogous parameter of traditional microwave noise sources.     

海洛因成瘾大鼠脑神经元两种死亡方式的超微结构观察

基础及临床资料表明,海洛因成瘾可引起动物、人类多种脏器损害,包括脑在内;而脑组织神经元的超微病理变化类型的报道,国内外少见。     

扇贝多肽减轻中波紫外线诱导人真皮成纤维细胞损伤的超微结构研究

目的：观察扇贝多肽(polypeptide from Chlamys farreri,PCF)对中波紫外线(ultraviolet B,UVB)辐射损伤体外培养的人真皮成纤维细胞超微结构的影响。方法：建立单次UVB辐射损伤体外培养的人真皮成纤维细胞的病理模型,应用透射电镜观察细胞超微结构的变化。结果：模型组成纤维细胞超微结构在2h后即出现变化．包括胞内空泡形成、线粒体嵴断裂、基质空泡化、粗面内质网扩张、核异染色质浓缩及边集,呈现早期细胞凋亡改变。而用0．25％～l％的PCF预处理细胞30min,可减轻成纤维细胞受损的程度,且呈量效关系。结论：扇贝多肽可有效地保护人真皮成纤维细胞对抗UVB的辐射损伤。     

光动力作用对膀胱癌细胞株BIU-87凋亡发生率的影响

目的 :研究光动力抑癌作用机制。方法 :采用流式细胞仪检测光动力作用后人膀胱癌细胞株BIU -87凋亡发生率。结果 :光动力实验组人膀胱癌细胞株BIU -87凋亡发生率达 2 6.11± 2 .5 9% ,与对照组相比 ,差异非常显著性 (P <0 .0 1)。结论 :光动力作用能有效诱导人膀胱癌细胞株BIU -87的凋亡发生。这可能是其抑癌作用机制之一。     

Analysis of mode conversion in waveguide transition sections with surface impedance boundaries applied to VLF radio propagation

First- and second-order correction terms are derived for the reflection and transmission scattering coefficients for a step-type transition between two uniform waveguides with surface impedance boundaries. This analysis yields rigorous expressions for the differential transmission and reflection coefficients defined for an infinitesimal step transition. These coefficients are essential in the derivation of the coupled differential equations for the wave amplitudes in a transition section of gradually varying height.     

文昌鱼表皮中酚氧化酶的超微结构定位

文昌鱼是从无脊椎动物到脊椎动物的过渡类型,在进化上占有极重要的地位。本文以L－多巴为底物,显示酚氧化酶（PO）存在于文昌鱼体表上皮细胞的胞质中,PO颗粒呈圆形均质状,直径在420－700nm之间,电子密度较高,其外无膜包被。苯硫尿（PTU）抑制酚氧化酶反应,指出该反应为PO的特异性反应,而不是底物的自氧化或其它假阳性反应。     

Ultrastructural and functional changes of the proximal tubular epithelial cells in the renal cortex from spontaneously diabetic KKAy mice.

To investigate the morphological and functional changes of epithelial cells of proximal tubules in the early stage of diabetic nephropathy, we examined the ultrastructural changes of proximal convoluted tubular cells in spontaneously diabetic KKAy mice. KKAy mice already showed significant elevation of urinary albumin excretion at 16 weeks of age. Examination revealed that lysosomes were increased in number and conspicuous in the epithelial cells of the proximal convoluted tubules from KKAy mice at 40 weeks of age when compared to control C57BL mice. Furthermore, endogenous IgG was detected in the lysosomes of proximal tubular cells from KKAy mice. These findings suggested that reabsorption activity was elevated in the proximal tubules of KKAy mice at 40 weeks of age.     

培养脊神经节细胞酸性磷酸酶的超微分布

我们已经先后报道了线状溶酶体 (ＮＬＹ)在中枢神经细胞 (大脑大锥体细胞 ;小脑浦肯野氏细胞 ;脊髓前角运动细胞 )的分布[1] ,但至今未见神经节细胞ＮＬＹ的报道。本研究采用酸性磷酸酶[2 ] (ＡｃｉｄＰｈｏｓｐｈｏｔａｓｅ ,ＡＣＰ)的电镜酶细胞化学技术显示初代培养的胎鼠脊神经节细胞ＡＣＰ的分布 ,并进行了电镜观察 ,旨在探讨脊神经节细胞ＮＬＹ的存在和研究其生物学特性提供依据。材料与方法实验动物选用妊娠 14日的健康孕鼠 (Ｗｉｓｔａｒ种系 ) ,拉断头颈处死消毒后剖开子宫 ,取出胎鼠 ,超净工作台中 ,解剖镜下分离出胎鼠脊神经节 ,…     

Optimization of CORDIC cells in the backward circular rotation mode

The COordinate Rotation DIgital Computer (CORDIC) algorithm in the backward circular rotation mode efficiently computes phase estimation. In this letter, a set of new rules are proposed to design a CORDIC processor to achieve a given signal-to-noise ratio (SNR). To this end, two new approximate expressions to estimate the SNR are derived accounting for the approximation and quantization errors, respectively.     

Modeling the transition from ohmic to space charge limited current in organic semiconductors

This paper presents a model for charge transport in organic and polymeric diodes that provides a physical explanation of the transition from ohmic to space-charge limited current (SCLC) regimes. The proposed model is based on two established models: a unified model for the injection and transport of charge in organic diodes, including a proper boundary condition for the free charge density at the metal–organic interface; and a temperature and electric-field dependent mobility model. The model reproduces published experimental current–voltage characteristics (for different temperatures and device lengths). The modeling results highlight the importance of the boundary condition at the interface that is used to explain different trends and their transitions in the current–voltage characteristics: linear, quadratic and a higher than quadratic trend at high electric fields. The model uses a finite charge at the interface to eliminate any dependence of the parameters of the mobility model with the length of the organic layer. Importantly, this result differs from others that consider an infinite charge at the interface, and make use of a length-dependent mobility, or other more complex models that incorporate a dependence with the free charge density in order to avoid such a dependence with the device length.     

Investigation of the transition from tunneling to impact ionization multiplication in silicon p-n junctions

White noise spectra of diodes breaking down between 1·5 and 5 V have been used to investigate the details of the transition from tunneling to avalanche breakdown in silicon p-n junctions. It is found that the transition and carrier multiplication in these junctions is dominated by the influence of the threshold energies for ionization. Because this influence is not explicitly taken into account in the existing theories of carrier multiplication and noise, they are not applicable to low breakdown voltage diodes. Consequently, a multiplication onset model and alternate schemes for calculating the DC multiplication and noise in low breakdown voltage diodes are developed.Analysis of the noise data indicates that the threshold energies for ionization depend slightly on junction widths and, for the diodes employed in this study, range between 1·66–1·9 eV for electrons and 1·79–2·04 eV for holes. The minimum distance between ionizing collisions is found to range from 190 to 240 A for electrons and 200 to 250 A for holes.Application of the threshold energies for ionization to the multiplication onset model permits evaluation of the doping densities on both sides of the step junctions. From it, it is determined that the solubility of aluminum in silicon is N_A = 9·5 ± 0·5 × 10¹⁸ cm^?3.     

Design of mode converters for generating the TE11 mode from TM01 vircator at 4GHz

This work reports on measurements and calculations (coupled mode equations) on the conversion of transverse magnetic TM₀₁ vircator mode at 4 GHz to the linearly polarized TE₁₁ mode by means of mode converter systems using a circular waveguide with curvature. The mode converter is composed of a 38.78° bend with 39.07 cm curvature and a 50.78° inverse bend with 25.24 cm curvature in 9 cm internal diameter (ID) circular waveguide. The efficiency of conversion from TM₀₁ to TE₁₁ at 4 GHz exceeds 99%, and the overall efficiency from TM₀₁ to TE₁₁ exceeds 90% over a calculated range of 3.72–4.8 GHz.