Distribution of exogenous heavy metals in the hepatocytes of calves: a morphometric study

The objective of this study was to evaluate the presence of heavy metals in the hepatocytes of the animals fed a cadmium-supplemented diet and also receiving zinc and/or selenium in the injection form. The experiment involved four groups of calves (6-8, both sexes) receiving the heavy metals in various combinations for 95 days. Electron micrographs of liver cells were prepared and statistically evaluated using Student's t-test. A modified morphometric apparatus was used for morphometric examination. Exogenous cadmium showed marked accumulation in the hepatocytes. If, however, the cadmium diet was combined with zinc or selenium administration the amount of the reduction product was much lower.     

Localization of metals in cells of saprophagous soil arthropods (Isopoda, Diplopoda, Collembola)

This review summarizes results on the intracellular distribution of metals in cells of woodlice (Isopoda), millipedes (Diplopoda), and springtails (Collembola), which are three major groups of saprophagous arthropods contributing to the turnover of soil organic matter. Although the impact of metals and also metal pollution has inevitably been shown at levels of higher biological organization than subcellular mechanisms in these animal groups, the aim of this review is to focus exclusively on storage sites and aspects of intracellular metal metabolism. Thus, methodologically, results obtained by microscopical techniques such as histochemistry, X-ray microanalysis, energy filter transmission electron microscopy, or laser microprobe mass spectrometry were given preference. Results from atomic absorption spectrophotometry of cellular fractions were kept to a minimum. In all three taxa, the main intracellular metal storage sites are various types of "granules" which are widely distributed throughout cell types associated with the digestive system.     

中国成年男子全血及器官组织中稀土元素分布模式

在我国四个不同膳食类型地区(河北省、山西省、江苏省和四川省)采集16例急死正常成年男子尸体的心脏血、肝脏、脾脏、睾丸、肋骨5种器官组织样品。采用湿法消解,用ICP-MS法测定其15种稀土元素分量,它在器官组织中的蓄积浓度分别为肝(318.8ng/g)>肋骨(107.9ng/g)>睾丸(30.2ng/g)>脾脏(24.6 ng/g)>血(3.3 ng/mL);除血和肋骨中的La、Ce外,其余13种稀土元素在上述组织器官的分布模式均符合奥多-哈尔金斯定律;经球粒陨石归一化处理稀土元素在组织器官中的分布模式均存在轻稀土富集重稀土亏损(LaN/SmN>1和GdN/YbN>1)。     

Pigmented macrophages and related aggregates in the spleen of european sea bass dosed with heavy metals: Ultrastructure and explorative morphometric analysis

The ultrastructure and morphometrics of pigmented macrophages (PMs) were assessed in the spleen of European sea bass experimentally dosed with Cd and Hg. PMs occurred either as solitary cells or as variably structured aggregations, defined as macrophage aggregates (MAs). Light microscopy revealed a high degree of morphological heterogeneity amongst MAs of all experimental groups. At the ultrastructural level, MAs showed a heterogeneous pigment content that was not influenced by the treatment. Cytoplasm rarefaction/vacuolation and euchromatic nuclei, were observed in PMs of dosed fish. Undosed and Cd‐dosed samples differ significantly with regard to the following morphometric features: the Minor axis of the best fitting ellipse, Aspect Ratio, and Roundness. In Cd‐dosed fish, MAs showed reduced size and complexity. Lacunarity showed significant differences between undosed and both Cd and Hg‐dosed samples. These results suggest that heavy metals, and especially Cd, may influence the dynamics of PM aggregation/disaggregation. Variability in splenic MAs was observed both by light and electron microscopy. However, only the morphometric techniques adequately and objectively described the phenomenon, allowing a quantitative/statistical comparison of morphology among experimental groups. These morphometric analyses could be usefully applied in toxicological and ecotoxicological, as well as morpho‐functional studies.     

基于原位和RNT技术的摩擦试验机及其实验研究

针对目前传统摩擦磨损试验机的不足之处,开发了一种基于原位和RNT技术的摩擦磨损试验机。在合理设计和选取试验机工作系统及主要部件的基础上,采用原位全息显微技术和放射性核素技术,实现了对摩擦过程中材料磨痕表面微观形貌的在线原位观察和磨损量的实时精确测量。利用试验机对CuZ n20/100Cr6进行摩擦磨损性能实验,并对试验后试样进行了X射线电子能谱分析(XPS)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析研究。结果表明,磨痕表面形成耐磨层和晶粒细化是CuZ n20具有良好耐磨性的主要原因;试验机的实验结果精确,能为深入研究材料摩擦学行为提供重要参考依据。     

基于单目视觉的轮式机器人同步定位与地图构建

如何降低计算复杂度是视觉机器人同步定位与地图(SLAM)构建的热点问题.提出一种基于单目视觉的低计算复杂度的轮式机器人同步定位与地图构建算法.该算法在观测步通过图像处理与分析,识别特征点并进行定位,将轮式机器人的视觉投影与空间物体的几何关系转换为计算机器人相对特征点的距离和角度.整体算法步骤按照预测、观测、数据关联、更新、地图构建的递推算法进行同步定位与地图构建.提出的算法可识别环境目标,并进行平滑运动.在滤波观测步只处理单帧图像数据,和Active Vision和立体视觉方法相比,降低了算法的计算复杂度.     

ICP-MS法测定316H不锈钢中锌硒

采用5mL王水溶解试样,在最佳测量条件下,用标准曲线法建立校准曲线,通过基体匹配和内标校正相结合的方式消除基体效应,实现了ICP-MS法测定316H不锈钢中锌、硒的准确测定,各元素的相关系数均在0.999以上.将本方法用于实际样品的检测,测得结果的相对标准偏差(RSD,n=11)为7.4％～10.6％,加标回收率在92...     

Expression and localization of translationally controlled tumor protein in rat urinary organs

This study describes the very first assessment of the expression and localization of translationally controlled tumor protein (TCTP) in adult rat urinary organs. TCTP expression levels in kidneys, urinary bladder, and urethra were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE) and Western blotting, and its cellular localization was examined immunohistochemically in paraffin sections of various urinary organs. TCTP was found in all urinary organs. Its expression was high in the urethra and low in the bladder. TCTP was localized in glomerular podocytes, epithelium of proximal and distal renal tubules, in the loop of Henle, and in the transitional epithelium of the bladder and urethra, mostly in basal cell layers). The subcellular localization of TCTP in these urinary organs was cytoplasmic. These findings suggest that TCTP may be involved in urine formation and excretion. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

基于激光雷达的移动机器人同时定位与地图创建的研究

应用同时定位与地图创建理论建立全区域覆盖移动机器人导航系统,融合航位推算理论和基于环境特征的定位方法,设计了基于光电编码器--磁航向传感器组合和LMS激光雷达的混合定位系统.使用扩展Kalman滤波技术完成了基于特征直线的机器人位置更新.通过计算机仿真,结果表明建立的混合定位系统和同时定位与地图创建方法是一种切实可行的全区域覆盖移动机器人的导航方法.     

Small sample parts recognition and localization from unfocused images in precision assembly systems using relative entropy

Recognition and localization of mechanical parts using machine vision is a common approach in precision assembly systems. However, positional inaccuracy in assembly systems often produces unfocused images. Hence, existing methods of part recognition and localization are vulnerable to failure. In this paper, we present a part recognition and localization method, based on relative entropy, which can be applied to small samples. First, a template image is generated based on the contour of the parts and divided into several regions. The intensity distribution of the regions was sampled to generate template features. Then, the captured image is segmented using the Gaussian mixture model and the expectation maximum algorithm to extract the target part in the image. Part features are also generated by sampling the target part image using the template features. Furthermore, an optimization model is established in which the objective function is the sum of the relative entropy between the image features, the template features, and the region matching error correction term. By solving the optimization model, the location of the part can be obtained. The proposed method is compared with the edge and invariant feature-based methods through experiments. The results show that the proposed method has higher robustness and is suitable for the recognition and localization of parts with unfocused images. By using this method, the flexibility and reliability of precision assembly systems can be improved.     

彩色眼底图像视盘自动定位与分割

针对彩色眼底图像视盘定位时图像边缘高亮环对定位准确率的影响,提出了一种有效的图像预处理方法。针对已有的视盘分割算法中存在的问题,提出了一种结合形态学、椭圆拟合及梯度矢量流(GVF)Snake模型的分割算法。提出的预处理方法首先利用最小二乘法拟合出眼底图像的边界,然后裁剪掉边界的一部分高亮像素点,最后进行视盘定位。视盘分割算法则首先进行血管擦除,然后用椭圆拟合提取初始轮廓,最后使用GVF Snake精确调整视盘边界。用提出的方法对Messidor眼底图像数据库1 200幅图像上进行了实验,结果显示:视盘定位准确率由原来没经过预处理的95.4%提升到了98.7%;视盘分割错误率与当前已知最好的算法相比由12.5%降低到了9.39%。结果表明:提出的眼底图像视盘自动定位与分割方法准确率高、实用性强,可以用于眼科疾病的计算机辅助诊断。     

面向移动机器人自定位的无线网络构造算法及实现

针对移动机器人的自定位问题,研制一种无线定位网络结点,该结点由超声模块和无线射频模块组成,根据超声与无线射频信号的到达时间差计算机器人与网络结点的相对位置关系,借助扩展的卡尔曼滤波器实现机器人的自定位和对网络结点的同步定位.然后,提出一种无线定位网络的自主构建算法,通过机器人动态分配网络结点,实现对环境的完备最小覆盖.仿真与实验表明该网络构造算法及定位技术能够满足较大规模环境下移动机器人的自定位要求.     

基于深度学习的视觉同时定位与建图研究进展

随着机器视觉的不断发展,视觉传感器其小巧轻便、价格低廉等优势,使得视觉同时定位与建图(VSLAM)越来越受人们关注,深度学习为处理VSLAM问题提供了新的方法与思路。本文综述了近年来基于深度学习的VSLAM方法。首先回顾了VSLAM的发展历程,系统阐释了VSLAM的基本原理与组成结构。然后从视觉里程计(VO)、回环检测与建图3个方面分析各类基于深度学习的方法,从特征提取与特征匹配、深度估计与位姿估计及关键帧选择等3个部分阐述了深度学习在VO中的应用;基于场景表达方式的不同,总结了几何建图、语义建图及广义建图中的深度学习方法。接着介绍了目前VSLAM常用的各种数据集以及性能评估指标。最后指出了目前VSLAM面临的难题与挑战,展望未来深度学习与VSLAM结合的研究趋势与发展方向。     

WSNs节点定位不适定性的诊断与克服

节点定位技术是无线传感器网络(wireless sensor networks,WSNs)应用中重要的支撑技术之一.在WSNs节点定位中,可以通过接收信号强度指示信息计算出节点间的距离,根据节点之间的几何关系利用最小二乘估计(least square estimate,LSE)求解待定节点的坐标.但在实验和应用过程中发现,当采用不同空间位置的参考节点进行定位时,有时会出现定位误差的巨大变化.对这种现象进行了研究,发现节点定位中存在一定的不适定性,表现为定位结果受测距误差影响较大,定位结果不稳定.分析了不适定性产生的原因和机理,提出WSNs节点定位时首先需要进行不适定性诊断,通过条件数法诊断不适定性和评估不适定性程度,对于适定的情况,仍然采用LSE法进行定位,对于不适定的情况,引入岭估计法用于克服节点定位中的不适定性.实验结果表明,岭估计有效克服了节点定位的不适定性,可将不适定情况下的三维定位误差减小至3 m左右,提高了定位结果的稳定性.     

Application of scanning electron microscopy (SEM) and microbead techniques to study the localization of p24 and p18 antigens of HIV-1 on the surface of HIV-1-infected H9-lymphocytes

Immunofluorescence staining techniques at present, when applied to follow the expression of HIV-1-specific antigens on infected cells, only give the information that the antigens detected are localized in the outer region of the membrane of the infected cell. We therefore set up a procedure using magnetic polystyrol particles coated with antibodies specific for the HIV-1 antigens under study, in combination with scanning electron microscopy. We were able to demonstrate that p24 and p18 structural antigens are clearly expressed on the surface of HIV-1-infected H9 lymphocytes. This means that there was no steric hindrance for structures of cell-like size specific for HIV-1 antigens to interact with their target antigens. Other antigens may be hidden in membrane structures and are therefore inaccessible, for example, to the beads used here, which were of a similar size to antigen-specific cells in vivo. The results of this model system must be seen with respect to the interaction of antigen-specific cell-mediated immunity with full antibody-dependent cellular cytotoxicity, or without cytotoxic T lymphocytes, the mediator function of antibodies.     

水中重金属连续消解装置及性能研究

本研究设计了一种用于水体中重金属测定的连续消解装置,该消解装置可据水质特点调节消解温度、压力和流速。实际水样加标经消解后分析,8种金属离子(Cd、Pb、Cr、Cu、Zn、As、Fe和Mn)的平均回收率在93.1%~99.4%之间,RSD为3.3%~8.7%;通过对自来水、地下水、地表水和污水分别进行连续消解、微波消解和石墨消解,连续消解后溶液中8种金属元素浓度测定结果与微波消解和石墨消解无显著差异,且平行样相对误差不大于5%,表明本连续消解具有较高的准确度和精密度,适用于不同水体的消解分析要求。该连续消解装置可自由设定消解参数,实现自动化运行,通过与各类重金属在线监测仪器接口连接,有望实现监测过程中水样的自动化消解。     

微波消解ICP-AES法测定中药中铜、镉、铅、砷的方法研究

采用微波消解ICP-AES法同时测定中药中铜、镉、铅和砷的含量，加标回收率为94％～98％，RSD小于1％。方法准确、快捷、操作简单，适用于中药中重金属含量的测定。     

稀有难熔金属分析中样品的分解方法

本文报道了稀有难熔金属,Ｚｒ、Ｈｆ、Ｎｂ、Ｗ、Ｍｏ、Ｔｒ的常规分解方法,同时提出了新的溶样技术,如高压分解溶样,微液分解技术以及微波增压分解技术等亲的溶样方法、试验证明上述新溶液样可以理论地,解决诸多的难熔金属及其合金的消解问题。