Shape normalization of 3D cell nuclei using elastic spherical mapping

Topological analysis of cells and subcellular structures on the basis of image data, is one of the major trends in modern quantitative biology. However, due to the dynamic nature of cell biology, the optical appearance of different cells or even time-series of the same cell is undergoing substantial variations in shape and texture, which makes a comparison of shapes and distances across different cells a nontrivial task. In the absence of canonical invariances, a natural approach to the normalization of cells consists of spherical mapping, enabling the analysis of targeted regions in terms of canonical spherical coordinates, that is, radial distances and angles. In this work, we present a physically-based approach to spherical mapping, which has been applied for topological analysis of multichannel confocal laser scanning microscopy images of human fibroblast nuclei. Our experimental results demonstrate that spherical mapping of entire nuclear domains can automatically be obtained by inverting affine and elastic transformations, performed on a spherical finite element template mesh.     

基于激光共焦扫描显微镜方法的磨损表面三维数字化描述

表面形貌的精确描述在许多领域诸如材料、生物医学、摩擦学和机器状态监测等领域变得越来越重要。开发了一种基于激光共焦显微镜和图像处理技术的研究磨损表面及表面参数的新方法。首先用B io-rad Rad iance 2000激光共焦显微镜方法获得精确的三维表面形貌,然后用计算机辅助图像分析技术自动计算出表面特征参数。应用示例表明本文所研究的方法是可靠的,能对工程表面的表面粗糙度特征进行精确描述。     

Measurement of geometrical parameters in cocontinuous polymer blends: 3D versus 2D image analysis

Formulae of stereology are used to estimate 3D geometrical parameters of cocontinuous structures measured from 2D micrographs of polymer blends. 3D images of symmetric and nonsymmetric polymer blends made of fluorescently labelled polystyrene and styrene‐ran‐acrylonitrile copolymer were obtained with laser scanning confocal microscopy. Geometrical parameters of the blend interface, specifically volume fraction, surface area per unit volume (S _V ) and average of local mean curvature were measured directly from the 3D images and compared to the values estimated from analysis of a number of 2D slices combined with stereological relations. When the total length of phase boundary considered in the analysis of the 2D slices (L_Tot ) was at least 6000 times bigger than the characteristic length of the microstructure (S^?1_V ), the standard deviation for all the parameters measured became negligible. However, considerable discrepancies between the average values computed from 3D and 2D images were observed for any value of L_Tot . The mean curvature distribution was also measured from both the 3D images and the 2D slices. The distribution was estimated from the 2D slices but with a width about 2.4 times that of the true value obtained from the 3D images.     

Sample holder for axial rotation of specimens in 3D microscopy

In common light microscopy, observation of samples is only possible from one perspective. However, especially for larger three‐dimensional specimens observation from different views is desirable. Therefore, we are presenting a sample holder permitting rotation of the specimen around an axis perpendicular to the light path of the microscope. Thus, images can be put into a defined multidimensional context, enabling reliable three‐dimensional reconstructions. The device can be easily adapted to a great variety of common light microscopes and is suitable for various applications in science, education and industry, where the observation of three‐dimensional specimens is essential. Fluorescence z‐projection images of copepods and ixodidae ticks at different rotation angles obtained by confocal laser scanning microscopy and light sheet fluorescence microscopy are reported as representative results.     

Three-dimensional analysis of cell nucleus structures visualized by confocal scanning laser microscopy

Studies of the three-dimensional (3-D) organization of cell nuclei are becoming increasingly important for the understanding of basic cellular events such as growth and differentiation. Modern methods of molecular biology, including in situ hybridization and immunofluorescence, allow the visualization of specific nuclear structures and the study of spatial arrangements of chromosome domains in interphase nuclei. Specific methods for labelling nuclear structures are used to develop computerized techniques for the automated analysis of the 3-D organization of cell nuclei. For this purpose, a coordinate system suitable for the analysis of tri-axial ellipsoidal nuclei is determined. High-resolution 3-D images are obtained using confocal scanning laser microscopy. The results demonstrate that with these methods it is possible to recognize the distribution of visualized structures and to obtain useful information regarding the 3-D organization of the nuclear structure of different cell systems.     

直齿圆柱齿轮的三维建模及有限元分析

以Pro/E为开发平台,Pro/Program为开发工具,对标准直齿圆柱齿轮的参数化建模进行了详细的介绍.只要按提示输入标准直齿圆柱齿轮的5个基本参数,就可以得到精确的直齿齿轮的三维实体.同时利用ANSYS有限元分析软件的特点,可以在不脱离Pro/E和ANSYS这两个软件的情况下对直齿圆柱齿轮进行有限元分析.     

High-precision distance measurements and volume-conserving segmentation of objects near and below the resolution limit in three-dimensional confocal fluorescence microscopy

This study presents a method for high-precision distance measurements and for the volume-conserving segmentation of fluorescent objects with a size of the order of the microscopic observation volume. The segmentation was performed via a model-based approach, using an algorithm that was calibrated by the microscopic point spread function. Its performance was evaluated for three different fluorochromes using model images and fluorescent microspheres as test targets. The fundamental limits which the microscopic imaging process imposes on the accuracy of volume and distance measurements were evaluated in detail. A method for the calibration of the axial stepwidth of a confocal microscope is presented. The results suggest that in biological applications, 3D distances and radii of objects in cell nuclei can be determined with an accuracy of ≤ 60 nm. Using objects of different spectral signature, 3D distance measurements substantially below the lateral half width of the confocal point spread function are feasible. This is shown both theoretically and experimentally.     

Application of confocal scanning laser microscopy for an automated nuclear grading of prostate lesions in three dimensions

Confocal scanning laser microscopy provides the opportunity to obtain three-dimensional (3-D) images by piling up consecutive confocal planes. This technique was applied to capture 3-D images from 100-μm-thick tissue blocks from prostate lesions (hyperplasia, dysplasia, adenocarcinomas). Automated methods were implemented to perform a nuclear grading of 3-D cell nuclei from these specimens. Special attention was focused on the development of a new approach to 3-D chromatin texture analysis. This method uses mathematical morphology operations to tessellate the chromatin into homogeneous domains. The nuclear features (volume, shape, texture) were subjected to a discriminant analysis. Using a set of five features, the classification of cell nuclei yielded an accuracy of 963%. The results indicate the potential of 3-D imaging and analysis techniques for an automated nuclear grading of prostate lesions.     

立体车库钢结构参数化设计分析与绘图方法

以垂直升降式立体车库钢结构骨架为研究对象,针对拓扑组成复杂而设计参数变化的立体车库钢结构,提出基于参数化方式建立三维有限元模型,采用Visual C++6.0语言编制主控程序,利用SAP50软件进行静态、动态分析,对钢结构强度、刚度和稳定性进行校核,通过分析结果的数据接口文件传递,驱动AutoCAD实现参数化绘制工程图.     

大型油罐容量计量中3D空间建模方法研究与比对试验分析

油罐的容量计量是石化企业生产运行的核心工作之一.为了提高计量检定效率,提出一种基于三维激光扫描原理的油罐容量全自动测量方法.讨论了一种扫描点云数据分析方法,通过三角网格和曲面拟和的方法计算出不同液位高度对应的油罐容积值.设计了对比试验系统,选取60 m~3和37 m~3两个标准油罐为研究对象,根据OIML R71和R80的技术要求,以0.025%准确度的容量比较法测量值为参考依据,三维激光扫描方法进行油罐容量测量具有好的复现性,而测得的容量值相对偏差满液位量程处可达0.4%,验证了这种方法的有效性,而且有效提高了油罐容量检定工作效率.     

脉冲漏磁检测的三维场特征分析及缺陷分类识别

漏磁检测方法广泛应用于石油、运输及化工等行业中金属的缺陷检测.介绍了漏磁检测原理,采用有限元法建立了三维缺陷脉冲漏磁检测模型,分析了缺陷脉冲漏磁场B_x、B_y和B_z分量的特点.结果表明,与传统漏磁检测系统提取缺陷漏磁场水平分量B_x和法向分量B_z进行缺陷识别相比较,三维缺陷脉冲漏磁场分量的提取将提供更多有关缺陷尺寸、位置等信息,尤其是当外加磁场方向与缺陷主平面近似平行时.最后给出了实验验证,实验结果与仿真分析有较好的一致性,这说明有限元仿真分析对实际脉冲漏磁检测系统的设计有重要的指导意义.     

Dynamics of subcellular organelles, growth hormone, Rab3B, SNAP-25, and syntaxin in rat pituitary cells caused by growth hormone releasing hormone and somatostatin

Rab3B is involved in the exocytosis of synaptic vesicles and secretory granules in the central nervous system and the anterior pituitary cells. The aim of this study was to elucidate both the role of rab3B in GH secretion and the mutual relationship of rab3B and SNARE proteins. Adult male rats were injected intravenously with 10 microg of growth hormone releasing hormone (GHRH) or 10 microg of somatostatin (SRIF). Untreated rats were used as controls, and their pituitary glands were sectioned for histochemical examination. Rab3B is localized on the limiting membrane of the secretory granules and the cytosol. Confocal laser scanning microscopic observation of immunohistochemical double staining of rab3B and GH revealed that immunoreactivity of rab3B increased in GHRH-treated rats and decreased in SRIF-treated rats. Confocal laser scanning microscopic observation of immunohistochemical double staining of SNAP-25, syntaxin, and rab3B revealed the co-localization of rab3B and these SNARE proteins in GHRH-treated rats, and their dissociation in SRIF-treated rats. These results suggest that rab3B plays a principal role in GH secretion in the anterior pituitary cells and that SNAP-25 and syntaxin act as co-workers with rab3B in the functional regulation of GH secretion.     

Robust incremental compensation of the light attenuation with depth in 3D fluorescence microscopy

Fluorescent signal intensities from confocal laser scanning microscopes (CLSM) suffer from several distortions inherent to the method. Namely, layers which lie deeper within the specimen are relatively dark due to absorption and scattering of both excitation and fluorescent light, photobleaching and/or other factors. Because of these effects, a quantitative analysis of images is not always possible without correction. Under certain assumptions, the decay of intensities can be estimated and used for a partial depth intensity correction. In this paper we propose an original robust incremental method for compensating the attenuation of intensity signals. Most previous correction methods are more or less empirical and based on fitting a decreasing parametric function to the section mean intensity curve computed by summing all pixel values in each section. The fitted curve is then used for the calculation of correction factors for each section and a new compensated sections series is computed. However, these methods do not perfectly correct the images. Hence, the algorithm we propose for the automatic correction of intensities relies on robust estimation, which automatically ignores pixels where measurements deviate from the decay model. It is based on techniques adopted from the computer vision literature for image motion estimation. The resulting algorithm is used to correct volumes acquired in CLSM. An implementation of such a restoration filter is discussed and examples of successful restorations are given.     

内燃机主轴承盖强度和刚度的三维有限元分析

本文内容包括主轴承盖三维实体造型、三维网格划分、载荷和约束处理,并以 Ｓ Ｌ４１０５ 柴油机悬挂式主轴承盖为例,应用 Ｓ Ａ Ｐ９３ 软件进行了三维有限元分析,计算精度较高。     

基于SolidWorks的圆锥破碎机三维建模设计及有限元分析

介绍了PY G B-1821型液压圆锥破碎机的工作原理、结构特点。并运用Solid W orks软件对PY G B-1821型破碎机各零件进行三维建模设计、虚拟装配和有限元分析,既改善了二维设计不直观的状况,又便于参数化修改和调整设计模型,大大提高了设计水平和设计效率,为圆锥破碎机的优化设计提供了有效参考。     

Calibration and quantification of fast intracellular motion (FIM) in living cells using correlation analysis

Video rate confocal laser scanning microscopy at the highest spatial and temporal resolution of backscattered light (BSL) imaging allowed for regular observation of fast intracellular motion (FIM) first revealed in living neoplastic cells. However, the absence of an objective evaluation has hampered further study of the mechanisms and biological significance of FIM. Particularly, a quantification of apparent differences in velocities that would complement and improve the current demonstration of FIM by color coding using the combination of red-green-blue (RGB) images had been missing. Standard methods of tracking or pattern recognition could not be applied because of the fuzzy nature of images of FIM. A search for a suitable method led to correlation analysis. It was calibrated on Brownian motion and a known type of motion, such as cell marginal ruffling, compared with FIM. Results approved its explanatory potential. Therefore, several crucial incidences of FIM could be analyzed. Apart from an argument against viewing FIM as a manifestation of simple Brownian motion, the correlation analysis of FIM in the adjacent peripheries of a rat fibroblast and a K4 rat sarcoma cell confirmed the notion of higher and uneven distribution of velocity of FIM in a tumor cell so far shown in color-coded images only. This result and other yet unpublished observations indicate that the velocity and topology of FIM can also contribute to a biological distinction between neoplastic and normal cells. Regular application of the correlation analysis should further expand the study of FIM for its mechanisms and predictive value. Such an approach should be thoroughly examined for a contribution to the knowledge of cancer cells.     

斜齿轮与斜齿轮轴的三维参数化建模及其接触分析研究

介绍了在SolidWorks环境下用Visual C 编程实现伴齿轮和斜齿轮轴三维参数化建模的方法,并用CosmosWorks对斜齿轮和斜齿轮轴的啮合模型作接触应力分析研究。     

Accuracy and noise analyses of 3D vibration measurements using laser Doppler vibrometer

The in-plane and out-of-plane vibration components are used for 3D vibration measurements. The latter can be calculated by using three laser scanning vibrometers (LSVs) or by moving a single LSV to three different locations. These vibration components are calculated from the vibration signals measured at each of the three locations and the angles between the local coordinates and the LSV locations. The accuracy of the in-plane and out-of-plane vibration components can be degraded depending on the measurement angle. In addition to accuracy, the noise contained in the LSV can be amplified depending on the measurement angle. Hence, it is necessary to implement an analysis methodology for the angles, which is conducted for 2D vibration measurements first before extended to 3D. Finally, experiments are performed for both 2D and 3D at small and appropriate angles, and the elicited results are compared to those elicited using a 3D accelerometer.     

转子三维实体有限元分析的前后处理及CAD接

研究了转子系统三维实体有限元网格的生成,提出子块串联2D编号、复杂曲面节点坐标插值等实用方法。上述方法弥补了通用网格自动生成方法的某些不足,比较简单、有效,可以在复杂形体有限元剖分时保持良好的单元形状。采用局域搜索法绘制等应力线图,并利用CAD接口程序实现了对计算结果的后处理,在自行研发的专用有限元程序设计中有普遍应用价值。为实际工程中关于复杂三维结构的前后处理问题提供了处理方法。