硼化物陶瓷粉末的合成与分析

采用自蔓延高温还原合成方法制备了TiB2和TiB2-A l2O3陶瓷粉末。利用XRD、XPS、SEM以及TEM等分析测试手段对合成粉末进行表征和分析。结果表明,TiB2和A l2O3分别以主晶相的形式存在于所合成的各自粉体之中。相比之下,TiB2单相陶瓷粉末颗粒分布较宽。由于SHS温度很高,部分颗粒形成团聚,宏观上使颗粒的平均粒径变大(>5μm);而TiB2-A l2O3复合陶瓷粉末,因合成过程中A l2O3的形成,使得颗粒粒度分布明显变窄,分布均匀,颗粒尺寸也相应减小。这可能主要与复合粉末合成过程中不同颗粒间形成良好结合的界面有关。     

电火场铜导线熔痕形态特征的识别

通过扫描电镜对电火场中铜导线熔痕宏观及微观形态特征进行识别,为火灾的鉴定工作提供科学依据。火烧熔痕与短路熔痕特征主要区别是：火烧熔痕线径是短路熔痕线径的2倍;火烧熔痕与导线连接处有明显的温度过渡区而短路熔痕没有;多股导线火烧熔痕铜丝呈粘连态,多股导线短路熔痕铜丝呈分散态;火烧熔痕表面和内部均没有孔洞,短路熔痕表面和内部分布着大量的气孔和缩孔。一次短路熔痕断面上的孔洞直径较小,数密度较大,分布较均匀,二次短路熔痕断面上的孔洞直径较大,数密度较小,分布不太均匀。     

电解沉积纳米镍退火析出相的EBSD分析

电解沉积方法制备的纳米晶镍经650℃退火处理后，晶粒发生了长大，在晶内沿特定晶面析出了第二相颗粒，样品的拉伸断口为沿晶断口。利用EDS和EBSD对这种第二相析出物进行的成份分析和结构／取向分析表明：这种第二相颗粒是NiS2颗粒，其晶格取向与基体镍保持一致。NiS2颗粒沿基体镍的（001）面析出导致了晶界生长为台阶状并使晶界弱化。     

基于流变学的初生固相定量表征

根据初生固相的形貌、尺寸和数量对半固态合金熔体流变性能的影响作用,提出了对半固态合金熔体初生固相的定量表征方法。该方法首先对初生固相颗粒边界进行平滑处理、对聚集或粘连在一起的初生固相颗粒进行分离以及根据设定的阈值筛选并剔除取样过程形成的小颗粒,然后再利用图像分析软件统计计算半固态合金熔体中初生固相的体积分数、尺寸大小和圆整度等微观结构参量。利用这一方法得到的半固态合金熔体中初生固相的特征参数为半固态合金熔体的微观流变学研究提供了可靠的数据。     

颗粒复合材料中的三维晶粒长大与显微组织仿真设计研究

本文首先报告了作者自行研制的单相块材和颗粒增强复合材料中2D和3D晶粒组织演变过程Monte Carlo仿真算法和软件;继而扼要讨论了相关的理论发现及其在复合材料显微组织建模与设计中的应用。与多种真实材料实验数据比较研究表明,本文研究成果比文献中已有理论模型和仿真方法更适合于研究和预报复相材料中第二相粒子对基体晶粒组织热稳定性的影响规律。     

涂层法制备SiC_f/γ-TiAl基复合材料的基体微观组织

采用金相显微镜、X射线衍射仪、扫描电镜及能谱仪对纤维涂层法结合真空热压工艺制备的SiCf/Ti-43Al-9V复合材料基体微观组织的形成进行研究。结果表明,磁控溅射法制备的γ-TiAl涂层与纤维结合良好,与靶材成分基本一致,涂层呈柱状晶生长并且在生长过程中没有发生明显粗化;SiCf/Ti-43Al-9V复合材料基体是由γ相、α2/γ片层组织和B2相组成,与原始靶材合金的相组成一样。复合材料基体中的B2相在离纤维较远处出现,其V含量比原始靶材合金中B2相的低。B2相的分布与热压过程中纤维中C的扩散密切相关。     

骨唾液酸蛋白与肿瘤

骨唾液酸蛋白(BSP)是存在于细胞外基质中的一种高度磷酸化和糖基化的分泌性非胶原蛋白，主要分布在矿化组织中，参与骨骼的矿化、转换、分化以及骨吸收等生理病理过程。近年来，BSP在骨转移瘤中的高表达提示它在肿瘤的生长、浸润和转移中发挥重要作用。现主要综述BSP的结构功能、调节机制及其与肿瘤的关系。     

钼靶摄影对乳腺钙化的诊断价值

目的：探讨钼靶摄影对乳腺钙化在乳腺良恶性疾病中的价值。方法：对96例经手术或穿刺活检病理证实的良恶性钙化钼靶X线片进行回顾性分析。结果：96例乳腺钙化中，良性病变为64例，占67％，恶性病变为32例，占33％。结论：良性钙化一般具有颗粒较粗、数目较少、密度较高、分布相对较局限的特点，但如出现双侧乳腺弥散性钙化分布，也不除外良性病变可能，需严密随访或活检证实：恶性钙化一般具有颗粒较细、数目较多、密度较低等特点，尤其是沿导管走形的多形性杆状、线样及分支样钙化，则恶性可能性大；另外，还有一些成簇状分布的泥沙样钙化，则良恶性影像学有重叠，需要活检证实。     

嗜酸性细胞胃炎中的肥大细胞

目的研究嗜酸性细胞胃炎中的肥大细胞的分布及其意义。方法27例嗜酸性细胞胃炎常规切片．分别做pH6.40.5％甲苯胺蓝染色显示肥大细胞和2％硫染色人细胞异染颗粒，此镜观察。结果：在胃粘膜、粘膜下层及溃疡的肉芽组织中．均可见未释放型和释放型两种肥大细胞分布。不同部位不同类型的肥大细胞，被激活后均参与相应部位的炎性反应、引起粘膜溃疡和肉芽肿形成。结论本病的发生．主要与肥大细胞的分布和激活有着重要的关系。肥大细胞释放的各种介质、虽然双本病的发生起到重要作用，同时也具有一定的抗癌作用，这种病变属于一种迟发性免疫反应性疾病.     

急性早幼粒细胞白血病细胞形态学分型与临床关系初探

５２例急性早幼粒细胞白血病（Ｍ３），根据粗颗粒型早幼拉细胞的百分率进行分型：粗颗粒型早幼粒细胞＞７０％为Ｍ３ａ（粗颗粒型）；≤３０％为Ｍ３ｂ（细颗粒型）；在３０％～７０％之间为Ｍ３ｃ（混合颗粒型）。并就这三种亚型在性别、年龄分布上，以及在主要临床症状、血象、骨髓上不同的表现与特征作了描述和探讨。     

一种可视化空间随机分布粒子系统

目的用计算机建立空间随机分布粒子系统，实现在虚拟空间坐标系中自定义粒子分布的生成，为体视学理论方法研究建立计算机仿真实验平台。方法用数学方法描述所定义的粒子的分布及其三维形态特征，建立应用程序。采用X^2拟合优度检验法检验实际生成的粒子其空间位点分布的均匀性、独立性，采用动差法和Kolmogorov-Smirnov／Z拟合优度法检验粒子半径分布的正态性。结果在计算机上构建出一套可视化空间随机分布粒子系统。该系统可据要求自动生成包容空间和大小及坐标位点随机的粒子。100次虚拟粒子分布实验的均匀性、独立性和正态性检测结果表明，均匀性和独立性符合离散随机变量的理论分布。均匀性检测通过率达94．5％以上，独立性检测通过率超过92％。球粒子的半径分布符合正态分布。结论本文构建了一套计算机随机分布粒子系统，能在虚拟空间中生成可视化随机分布粒子及包容空间，输出符合用户定义的粒子系统，输出空间分布呈随机分布，粒子大小呈正态分布的球粒子。     

125I放射性粒子链腔道内近距离放疗的进展

放射性粒子链是将¹²⁵I粒子按照线性排列并置于管状导管中,使其剂量分布接近于圆柱形,进而适应腔道内的肿瘤放疗,发挥出单粒子所达不到的治疗效果。本文旨在综述125I放射性粒子链的发展历史、剂量分布、置入方法以及临床应用。     

Fluorescence anisotropy of diphenylhexatriene and its cationic Trimethylamino derivative in liquid dipalmitoylphosphatidylcholine liposomes: opposing responses to isoflurane

Background

Single-particle tracking is a powerful tool for tracking individual particles with high precision. It provides useful information that allows the study of diffusion properties as well as the dynamics of movement. Changes in particle movement behavior, such as transitions between Brownian motion and temporary confinement, can reveal interesting biophysical interactions. Although useful applications exist to determine the paths of individual particles, only a few software implementations are available to analyze these data, and these implementations are generally not user-friendly and do not have a graphical interface,.

Results

Here, we present APM_GUI (Analyzing Particle Movement), which is a MatLab-implemented application with a Graphical User Interface. This user-friendly application detects confined movement considering non-random confinement when a particle remains in a region longer than a Brownian diffusant would remain. In addition, APM_GUI exports the results, which allows users to analyze this information using software that they are familiar with.

Conclusions

APM_GUI provides an open-source tool that quantifies diffusion coefficients and determines whether trajectories have non-random confinements. It also offers a simple and user-friendly tool that can be used by individuals without programming skills.     

The rapid alveolar absorption of diesel soot-adsorbed benzo[a]pyrene: bioavailability, metabolism and dosimetry of an inhaled particle-borne carcinogen

Exposure to diesel exhaust may contribute to lung cancer in humans. It remains unclear whether the carbonaceous core of the soot particle or its coat of adsorbed/condensed organics contributes most to cancer risk. Equally unclear are the extent and rate at which organic procarcinogens desorb from soot particles in the lungs following inhalation exposure and the extent of their metabolic activation in the lungs. To explore the basic relationship between a model polycyclic aromatic hydrocarbon (PAH) and a typical carrier particle, we investigated the rate and extent of release and metabolic fate of benzo[a]pyrene (BaP) adsorbed on the carbonaceous core of diesel soot. The native organic content of the soot had been denuded by toluene extraction. Exogenous BaP was adsorbed onto the denuded soot as a surface coating corresponding to 25% of a monomolecular layer. Dogs were exposed by inhalation to an aerosol bolus of the soot-adsorbed BAP: Following deposition in the alveolar region a fraction of BaP was rapidly desorbed from the soot and quickly absorbed into the circulation. Release rates then decreased drastically. When coatings reached approximately 16% of a monolayer the remaining BaP was not bioavailable and was retained on the particles after 5.6 months in the lung. However, the bioavailability of particles transported to the lymph nodes was markedly higher; after 5.6 months the surface coating of BaP was reduced to 10%. BaP that remained adsorbed on the soot surface after this period was approximately 30% parent compound. In contrast, the rapidly released pulse of BaP, which was quickly absorbed through the alveolar epithelium after inhalation, appeared mostly unmetabolized in the circulation, along with low concentrations of phase I and phase II BaP metabolites. However, within approximately 1 h this rapidly absorbed fraction of BaP was systemically metabolized into mostly conjugated phase II metabolites. The results indicate that absorption through the alveolar epithelium is an important route of entry to the circulation of unmetabolized PAHS:     

Membrane microdomains emergence through non-homogeneous diffusion

ABSTRACT: BACKGROUND: In the classical view, cell membrane proteins undergo isotropic random motion, that is a 2D Brownian diffusion that should result in an homogeneous distribution of concentration. It is, however, far from the reality: Membrane proteins can assemble into so-called microdomains (sometimes called lipid rafts) which also display a specific lipid composition. RESULTS: The amount of this so-called overconcentration at equilibrium is simply related to the ratio of diffusion coefficients between zones of high and low diffusion. Expanding the model to include particle interaction, we show that inhomogeneous diffusion can impact particles clusterization as well. The clusters of particles were more numerous and appear for a lower value of interaction strength in the zones of low diffusion compared to zones of high diffusion. CONCLUSION: Provided we assume stable viscosity heterogeneity in the membrane, our model proposes a simple mechanism to explain particle concentration heterogeneity. It has also a non-trivial impact on density of particles when interaction is added. This could potentially have an impact on membrane chemical reactions and oligomerization.     

Transient solution to the bioheat equation and optimization for magnetic fluid hyperthermia treatment.

Two finite concentric spherical regions were considered as the tissue model for magnetic fluid hyperthermia treatment. The inner sphere represents the diseased tissue containing magnetic particles that generate heat when an alternating magnetic field is applied. The outer sphere represents the healthy tissue. Blood perfusion effects are included in both the regions. Analytical and numerical solutions of the one-dimensional bioheat transfer equation were obtained with constant and spatially varying heat generation in the inner sphere. The numerical solution was found to be in good agreement with the analytical solution. In an ideal hyperthermia treatment, all the diseased tissues should be selectively heated without affecting any healthy tissue. The present work optimized the magnetic particle concentration in an attempt to achieve the ideal hyperthermia conditions. It was found that, for a fixed amount of magnetic particles, optimizing the magnetic particle distribution in the diseased tissue can significantly enhance the therapeutic temperature levels in the diseased tissue while maintaining the same level of heating in the healthy tissue.     

压缩变形对铁硅合金中MnS粒子析出行为的影响规律研究

对充分固溶及时效处理的铁硅合金Fe-3%Si-Mn-S在室温下进行了不同应变量的压缩变形,应用EBSD技术测定了样品中各形变晶粒的取向,以及利用SEM观测了各晶粒内部MnS析出粒子的形貌、尺寸及分布特征,探讨形变对MnS粒子析出行为的影响规律。结果表明:1)相同应变量下,不同取向晶粒内粒子析出存在差异,且随变形量增加,粒子尺寸变化率从1.6%逐步增加至62.4%,晶粒取向影响显著;2)随变形量增加,析出粒子的平均尺寸有明显起伏,而粒子面积百分量与粒子平均尺寸变化趋势呈反比;3)粒子被位错切碎同时有粒子形核析出;大粒子熟化与第二相粒子回溶同时存在。     

Cellular uptake of magnetic fluid particles and their effects on human adenocarcinoma cells exposed to AC magnetic fields in vitro

Suspensions of coated superparamagnetic particles (magnetic fluids, MF) in AC magnetic fields have a pronounced specific absorption rate (SAR) per mass compared to multidomain particles. The aim of the present study was to investigate cellular uptake and the biological effects of AC magnetic field excited bio-compatible magnetic fluids on human carcinoma cells in vitro. One of the fluids tested was a dextran magnetite, which has a very low cyto-toxicity with survival fractions (SF) between 0.8 and 0.9 at concentrations of up to 5mg ferrite per ml. Human carcinoma cells intracellularly accumulate up to 1pg ferrite/cell which has been demonstrated by electron microscopy (TEM), X-ray spectroscopy and measurements of intracellular iron. It has been shown that the ferrite core is not altered intracellularly, but many of the dextran shells are degraded which yields particle chains and other aggregates observed in TEM. Semi-solid pellets of the tumour cells were treated with AC magnetic fields (520 kHz, 4–12.5kA/m) or waterbath hyperthermia at 43 and 45d`C, in presence of extracellular and/or intracellular magnetic fluid particles. Although MF heating is produced from individual particles, the survival fractions of MF heated and water bath heated cells are equal. In fact, the extracellular MF particle distribution is homogeneous enough to obtain similar inactivation. In contrast to earlier reports intracellular dextran magnetite particles in AC magnetic fields did not induce cell inactivation. Since the amount of intracellular ferrite should be indeed large enough for cell inactivation, the loss of dextran shells is most probably the main cause of limited effectiveness of the intracellular magnetite particles. The present work has demonstrated that: (1) MFH is able to inactivate tumour cells in vitro to at least the same extent as water bath hyperthermia; and (2) that there is a sensitizer effect of ferrofluids at 43d`C probably caused by free ferric ions which induce oxidative stress; and (3) that there is no cytotoxic effect of intracellular dextran magnetite particles 30–180min excited with AC magnetic fields used in this study. For the new method the term ‘magnetic fluid hyperthermia (MFH)’ is proposed.     

基于矩和傅里叶描述子的云雨粒子图像识别方法

云雨粒子的形状是云．雨研究的重要课题,也是云雨类型判别的重要依据。为了获得不同粒子的形状信息,从光学图像法的基本原理出发,采用数字图像处理的方法对云雨粒子图像进行分析,得出了云雨粒子的几何参数特征,提出了利用矩和傅立叶描述子来构建云雨粒子形状特征向量的方法,并进行了对比分析,所组成的特征向量可以直接为云雨粒子的分类所用,在实际应用时应根据实际情况选择所取傅立叶描述子的个数,为降水粒子的形状识别提供了基础,这对降水识别模型的建立具有重要的应用价值。     

Mineral dusts in lungs with scar or scar cancer

Five lungs with small scars and five lungs with small scar associated cancers, were studied by light and scanning electron microscopy and x-ray energy dispersive spectrometry. Six hundred particles were photographed and their physical and chemical properties analyzed from scar, cancer, or normal alveolar tissue on carbon planchet-mounted, deparaffinized and low temperature-ashed sections. Amosite/crocidolite fibers were accumulated only in one cancerous lung. All other lungs shared similar types of mineral particles. The lungs with noncancer scars, however, showed an increase in the ratio of aluminum and calcium salts (non-silicates), while the lungs with scar cancers had a higher ratio of silicates. These patterns of particle distribution were similar in different areas of the same lung, despite the fact mechanism is unclear, these results are consistent with the possibility that the pattern of mineral particle distribution in a lung may influence the formation of cancer in a scar.