婴儿黑色素神经外胚瘤的电镜观察

婴儿黑色素神经外胚瘤(MNTI)是国际公认的一种罕见疾病。就我们所知,自1918年由Krompecher首先报告此瘤至今,国外仅有90余例报告,国内只有极少个案报告。我院1970年以后,在临床上曾诊治两例经病理检验确诊为这一种瘤的患儿,并对其中一例手术切除的瘤块进行了超微结构研究。肿瘤组织在电镜下可见两种细胞群,一种是含黑色素的细胞,另一种是无黑色素的小园细胞。色素细胞呈多角或长梭形,彼此以上皮连接方式相连,形成细胞团或围成腔隙。有时可见基底膜将有色素的细胞包围。有色素细胞的胞核富于斑块状异染色质,核膜边缘不齐,胞浆比较丰富。胞浆内除见有线粒体、粗面内质网和高尔基复合体外,还存在许多处在不同发育阶段(Ⅱ—Ⅳ期)的黑色素小体。这些小体为园形或呈棒状,常可在棒状小体     

骨髓瘤瘤细胞的超微形态研究

本文报道了8例骨髓瘤(包括5例多发性骨髓瘤,3例轻链病)瘤细胞的超微形态改变。所见各例瘤细胞的分化程度不同,电镜下瘤细胞的形态变化较大,分化较好的瘤细胞,形态接近正常浆细胞,分化越差,异常形态特征明显。8例标本中,一例有大量核内包涵体(图1),3例有Russell小体(图2),其中一例的Russell小体特别丰富。另一例中,见到结晶体(图3)具有周期性排列的线条结构。此外,在4例骨髓瘤细胞中见到微丝,其中二例尤为显著。本文对骨髓瘤细胞在电镜下主要超微形态改变,以及核内包涵体,胞浆包涵体、胞浆微丝的     

基于DNA序列信息的核小体位点预测

核小体位点参与很多细胞活动并且在调控细胞进程中起重要作用,核小体位点的精确定位对生物医学和药物学有重大意义。该文结合机器学习算法和DNA序列信息建立一个新的核小体位点预测模型,目的是为了更快更精确地预测核小体位点。实验中使用K间隔核酸对组成特征和位置特异性核苷酸偏好特征将DNA序列进行编码,然后使用支持向量机对模型进行训练和分类预测。最后将该方法和目前主流的核小体位点预测模型在相同的数据集上做Jackknife测试,实验结果证明了该方法提高了核小体位点预测的正确率。     

间变性大细胞微绒毛淋巴瘤的超微结构观察及鉴别诊断

目的：探讨间变性大细胞微绒毛淋巴瘤的超微结构特点及鉴别诊断。方法：结合光镜、免疫组化及临床资料,对2例间变性大细胞微绒毛淋巴瘤进行超微结构观察。结果：光镜下,肿瘤呈窦性、巢团状浸润生长,瘤细胞排列紧密,体积大,核仁清楚。免疫组化显示瘤细胞CD30、EMA阳性。电镜下,瘤细胞表面有大量长短不一,粗细不等的微绒毛。胞质内有少量线粒体、核糖体、粗面内质网及高尔基复合体,1例偶见溶酶体样颗粒。核不规则,核仁明显,无细胞连接、基底膜及黑色素小体。结论：间变性大细胞微绒毛淋巴瘤的超微结构特征易与转移性低分化腺癌、恶性间皮瘤、黑色素瘤及毛细胞白血病鉴别。     

酵母和果蝇胚胎期核小体定位模式比较研究

在进行酵母与果蝇胚胎期核小体定位研究时,发现不同物种或同一物种中不同表达模式基因与全体基因的排列比较中,核小体分布呈现出差异性。我们观察到酵母全体基因中核小体排列对核小体缺失区域(NFR)的基因3’端比基因5’端的影响小,而果蝇中对两者的影响却是一样的。且酵母与果蝇胚胎期沉默型基因中NFR的两个边界之间的核小体排列都出现了相同规律。它揭示了核小体组织在基因组的整个进化过程中具有的前进性,同时也具有保守性。     

电镜及免疫电镜在垂体腺瘤功能分类中的应用

应用电镜及免疫电镜技术对２１８例垂体腺瘤进行了观察分析;并根据瘤细胞超微结构及免疫细胞化学反应特点进行了分类。免疫电镜证实并非所有含纤维小体的瘤细胞为生长激素细胞,某些泌乳素细胞腺瘤亦可查见纤维小体,这提示纤维小体并不是垂体生长激素腺瘤特有的一个形态特点。本观察证实异位外排现象常属于少颗粒泌乳素细胞腺瘤的一个特点。促肾上腺皮质激素（ＡＣＴＨ）细胞腺瘤的分泌颗粒形状不规则,体积变异较大,瘤细胞内常含有成束的微纤维雄丝,有时瘤细胞核周围可形成环状纤维区。免疫电镜还揭示促性腺激素细胞腺瘤中含有卵泡刺激素细胞（ＦＳＨ）或黄体生成素（ＬＨ）细胞,ＦＳＨ细胞中可含有较多的分泌颗粒,体积小,电子密度高;ＬＨ细胞中分泌颗粒较多,体积大,形状不规则,电子密度低。本研究对２１例无功能性垂体腺瘤进行了分析,提示这一组肿瘤可进一步分类     

4例肾素瘤的超微结构分析

目的：研究肾素瘤临床表现与超微结构特点的关系,强调电镜在诊断此瘤的作用。方法：结合临床资料,对4例肾素瘤进行超微结构的观察与分析。结果：4例患者临床上均有高血压症状合并肾实质肿物,肿瘤切除后血压下降,随访无复发和转移。患者的高血压症状与肿瘤大小无关,与瘤细胞的功能状态有一定关系。电镜超微结构分析显示瘤细胞的核及胞浆中的细胞器呈现合成活跃的表现,扩大的粗面内质网池和高尔基体囊泡中可查见特异的菱形结晶状分泌颗粒。结论：肿瘤中菱形结晶状肾素分泌颗粒是确诊肾素瘤的关键。     

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。     

小细胞恶性间皮瘤的超微结构观察

应用电镜观察小细胞恶性间皮瘤的超微结构特点,对5例福尔马林固定后、经光镜及免疫组化检查过的胸膜及腹膜肿瘤标本进行常规电镜标本制备及电镜观察。超微观察显示肿瘤细胞呈小圆形及小梭形。5例均见腺腔样结构、细长微绒毛、紧密连接及发育良好的桥粒。较长的微绒毛长度与直径之比为13：1。见不连续基板（2例）、胞质内张力丝（2例）及微丝（4例）,2例同时见核旁分布的球形微丝小体。结论：细长微绒毛是包括低分化小细胞恶性问皮瘤在内的恶性间皮瘤的特征性超微结构。电镜观察对确定小细胞恶性问皮瘤的病理诊断及鉴别诊断有帮助。     

电镜及免疫电镜在垂体腺瘤功能分类中的应用

本研究应用电镜及免疫电镜技术对 2 1 8例垂体腺瘤进行了观察分析 ;并根据瘤细胞超微结构及免疫细胞化学反应特点进行了分类。免疫电镜证实并非所有含纤维小体的瘤细胞为生长激素细胞 ,某些泌乳素细胞腺瘤亦可查见纤维小体 ,这提示纤维小体并不是垂体生长激素腺瘤特有的一个形态特点。本观察证实异位外排现象常属于少颗粒泌乳素细胞腺瘤的一个特点。促肾上腺皮质激素 ( ACTH)细胞腺瘤的分泌颗粒形状不规则 ,体积变异较大 ,瘤细胞内常含有成束的微纤维丝 ,有时瘤细胞核周围可形成环状纤维区。根据以往观察 (主要是常规电镜观察 ) ,促性腺激…     

人体指纹谱中药物和气功作用相似性的探讨

人体正常指纹谱反映人体处于正常状态，人体异常指纹谱则反映人体出现病变或处于气功的发功状态。从人体指纹谱测试发现：药物和气功都可以使某些异常谱线减弱，甚至消失。这种相似的效果，表明药物的医疗作用和气功的治病作用在机理上有着一定的联系。     

体效应对超深亚微米SOI器件总剂量效应的影响

研究体偏置效应对超深亚微米绝缘体上硅（SOI,Silicon-on-insulator）器件总剂量效应的影响.在TG偏置下,辐照130nm PD（部分耗尽,partially depleted）SOI NMOSFET（N型金属-氧化物半导体场效应晶体管,n-type Metal-Oxide-Semiconductor Field-Effect Transistor）器件,监测辐照前后在不同体偏压下器件的电学参数.短沟道器件受到总剂量辐照影响更敏感,且宽长比越大,辐射导致的器件损伤亦更大.在辐射一定剂量后,部分耗尽器件将转变为全耗尽器件,并且可以观察到辐射诱导的耦合效应.对于10μm/0.35μm的器件,辐照后出现了明显的阈值电压漂移和大的泄漏电流.辐照前体偏压为负时的转移特性曲线相比于体电压为零时发生了正向漂移.当体电压Vb=-1.1V时部分耗尽器件变为全耗尽器件,|Vb|的继续增加无法导致耗尽区宽度的继续增加,说明体区负偏压已经无法实现耗尽区宽度的调制,因此器件的转移特性曲线也没有出现类似辐照前的正向漂移.     

Electron Transport in Strained-Silicon Directly on Insulator Ultrathin-Body n-MOSFETs With Body Thickness Ranging From 2 to 25 nm

The electron effective mobility in ultrathin-body n-channel metal-oxide-semiconductor field-effect transistors fabricated on Ge-free 30% strained-Si directly on insulator (SSDOI) is mapped as the body thickness is scaled. Effective mobility and device body thickness were extracted using current-voltage and gate-to-channel capacitance-voltage measurements as well as cross-sectional transmission electron microscopy. Devices with body thicknesses ranging from 2 to 25 nm are studied. Significant mobility enhancements ( ~1.8x) compared to unstrained SOI are observed for 30% SSDOI with body thicknesses of above 3.5 nm. The mobility exhibits a sharp drop as the body thickness is scaled below 3.5 nm     

Dosimetry in models of child and adult for low-frequency electric field

Induced electric field and current density in a child's body exposed to a 60-Hz electric field are calculated and compared with those for an adult's body. Because of the different proportions of the child body relative to those of the adult body, differences in the induced electric field and current density values in various organs are observed. These results are interpreted in terms of international guideline limits, and hypotheses regarding plausible interactions.     

Statistics of measured body loss for mobile phones

The variation in body loss for different users of a cellular handset is investigated. Measurements involving 200 test users of mobile communications (GSM) handsets have been performed and statistics are presented for a handset with three types of antennas. Differences in the body loss of up to 10 dB have been observed between users, thus indicating that body loss measurements for handsets should include several test persons. Depending on the antenna type, 8-13 test persons are required to obtain an estimate of the mean body loss with a ±1 dB confidence interval at a 90% level     

Human body shadowing variability in short-range indoor radio links at 3–11 GHz band

Measurement results for human body shadowing and local environmental effects in short-range indoor radio channels are presented. A narrowband measurement system, comprising a signal generator, two identical triangular monopoles and a spectrum analyser, was used in the measurements. When the radio link was periodically blocked by a human body with various objects in and around the link, fading depths of up to 15 dB and even more were observed at spot frequencies of 3–11 GHz band. Standard deviation and its range for human body blockage are estimated for different radio link scenarios simulating real environments. The distribution of human body shadowing was analysed and compared with known distribution functions.     

一株来自金雕的霉形体的形态研究

本文利用航向电镜观察了一株来自金雕的形体在培养过程中的各种形态。结果表明该霉形体的形态极其多变，主要有丝状分枝体、原质小体、较大型体和巨大型体。它们在固体培养和液体培养等条件下的形态变化各有特点和规律。同时还进一步证实，除原质小体外的细胞均有直接的分裂连续增殖，而原质小体由丝状分枝体和较大型体产生，经转主为其它形态后再增殖。     

Concurrent PBTI and hot carrier degradation in n-channel MuGFETs

The experimental investigations on the concurrent PBTI and CHC degradation in n-channel MuGFETs have been performed with different stress gate voltages, gate lengths, fin widths, and side surface orientations of fin body. The observed results suggest that the enhanced hot carrier degradation at elevated temperature is due to the interaction between PBTI and CHC degradation. The stress gate voltage is a dominant role in CHC degradation at elevated temperature. The device degradation is independent of the fin number and fin width when the total fin width is constant. The device degradation is more significant in 0° rotated fin body than in 45° rotated fin body.     

Distribution of filipin-sterol complexes in the bloodstream form of Trypanosoma brucei gambiense.

The polyene antibiotic, filipin, was used as a probe for demonstrating sterols in the plasma membrane of Trypanosoma brucei gambiense. Three different regions of the continuous plasma membrane over the cell body proper, flagellar pocket, and flagellum, were compared as to density and distribution of the filipin-sterol complexes by freeze-fracture method. The density of the complexes was highest in the cell body membrane and lowest over the flagellar pocket. The filipin-sterol complexes in the cell body membrane were distributed homogeneously on both the protoplasmic and exoplasmic faces except in the zone of flagellar attachment. This junctional zone showed a linear, complex-poor region. In the flagellar membranes, a line of complex-poor regions was observed along the juncture of the flagellum to the cell body. At the neck of the flagellar pocket, the membranes of the flagellar pocket and flagellum were closely opposed, with few filipin-sterol complexes on either membrane. At the base of the flagellar shaft, the complexes were completely lacking on both faces. Based on these observations, the zones of juncture observed in T.b. gambiense seems to be similar in ultrastructure to mammalian cell junctions, such as tight, gap, septate junctions and desmosomes, which show a nearly complete absence of the filipin-sterol complexes.     

Effects of heavy ion irradiation on ultra-deep-submicron partially-depleted SOI devices

The effects of the physical damages induced by heavy ion irradiation on the performance of partially-depleted SOI devices are experimentally investigated. After heavy ion exposure, different degradation phenomena are observed due to the random strike of heavy ions. A decrease of the saturation current and transconductance, and an enhanced gate-induced drain leakage current are observed, which are mainly attributed to the displacement damages that may be located in the channel, the depletion region of the drain/body junction or the gate-to-drain overlap region. Further, PDSOI devices with and without body contact are compared, which reveals the differences in the threshold voltage shift, the drain-induced barrier lowing effect, the transconductance and the kink effect. The results may provide a guideline for radiation hardened design.