A comparative study of the quantitative accuracy of three-dimensional reconstructions of spinal cord from serial histological sections

We evaluated the accuracy of estimating the volume of biological soft tissues from their three‐dimensional (3D) computer wireframe models, reconstructed from histological data sets obtained from guinea‐pig spinal cords. We compared quantification from two methods of three‐dimensional surface reconstruction to standard quantitative techniques, Cavalieri method employing planimetry and point counting and Geometric Best‐Fitting. This involved measuring a group of spinal cord segments and test objects to evaluate the accuracy of our novel quantification approaches. Once a quantitative methodology was standardized there was no statistical difference in volume measurement of spinal segments between quantification methods. We found that our 3D surface reconstructions’ ability to model precisely actual soft tissues provided an accurate volume quantification of complex anatomical structures as standard approaches of Cavalieri estimation and Geometric Best‐Fitting. Additionally, 3D reconstruction quantitatively interrogates and three‐dimensionally images spinal cord segments and obscured internal pathological features with approximately the same effort required for standard quantification alone.     

Surface roughness prediction through internal kernel information and external accelerometers using artificial neural networks

In this paper, the average surface roughness parameter (Ra) is predicted using artificial neural network (ANN) models and internal kernel information and external piezoelectric accelerometer data. Experiments were conducted to obtain data to develop ANN models to predict surface roughness. A total of 72 samples were used to develop two networks, one based on accelerometer inputs and the other on kernel inputs. The Matlab ANN Toolbox was used for the modeling. The two networks had similar characteristics. Feed-forward backpropagation, ‘newff’, was the network structure selected, with a Levenberg-Marquardt backpropagation training function, ‘trainlm’, and a backpropagation weight and bias learning function, ‘learngdm’. Samples obtained at the experimental stage were randomly divided into three groups to train (70% of the samples), validate (15% of the samples) and test (15% of the samples) the neural networks with a ‘dividerand’ data division function. The input processing functions used were ‘fixunknowns’, ‘removeconstantrows’ and ‘mapminmax’. The transfer function was ‘tansig’ for hidden layers and ‘purelin’ for the output layer. The output processing functions used were ‘removeconstantrows’ and ‘mapminmax’. The inputs consisted of the process parameters of radial depth of cut (Ae), the axial depth of cut (Ap), the spindle speed (N), the feed rate (f), the feed per tooth (fz), the cutting speed (Vc), the tooth passing frequency (ft), the cutting section (Cs), the material removal rate (MRR) and the cutting tool characteristics of the cutter radius (R), the number of teeth (Z) and the tool shape. The main difference between the two neural networks consisted of data origin: one considered data obtained with accelerometers and the other data collected in the NC kernel. Results showing high correlation factors between outputs and targets confirm that data provided by both internal and external sources can be useful for Ra prediction. However, NC kernel data provide several advantages.     

Endotracheal tube biofilm and ventilator‐associated pneumonia with mechanical ventilation

Objective: To analyze biofilm on internal and external surfaces of endotracheal tubes after their use in critical care patients, and to produce evidence of association between use of the tube, presence of biofilm, and the occurrence of pneumonia. Methods: This was a clinical study performed at the Intensive Care Unit of an emergency hospital in the interior of São Paulo state, Brazil. Data collection involved 30 endotracheal tubes used on adult patients for a period of ≥48 h of mechanical ventilation for scanning electron microscopy. Results: Analysis of the biofilm on the 30 tubes by scanning electron microscopy showed various abiotic and biotic structures, predominately on the internal surface, such as: fibrin network, erythrocytes, leukocytes, cocci, bacilli, and molds, among others. The intubation period of the endotracheal tube for ≥8 days represented one of the risk factors for ventilator‐associated pneumonia (RR 7.41, P < 0.001). Conclusions: The presence of the endotracheal tube permits microbial colonization, overall contributing to the development of biofilm and the occurrence of pneumonia. Microsc. Res. Tech. 77:305–312, 2014. © 2014 Wiley Periodicals, Inc.     

Cryo‐scanning electron microscopy investigation of the Octopus Vulgaris arm structures for the design of an octopus‐like arm artefact

Octopus vulgaris is a cephalopod of the Octopodidae family. It has four pairs of arms and two rows of suckers which perform many functions, including bending and elongation. For this reason the octopus was chosen as model to develop a new generation of soft‐body robots. In order to explain some of the fine structures of the octopus arm in relation to its specific ability, we examined the external and internal structures of O. vulgaris arms in a frozen‐hydrated state using cryo‐scanning electron microscopy. The arms showed skin with a very complex design that is useful to elongation, and a pore pattern distribution on their surface which is functional to cutaneous oxygen uptake. The analysis of freeze‐fractured frozen‐hydrated arm samples allowed us to describe the developmental differences in the relative proportion of the areas of axial nerve cord, intrinsic and extrinsic musculature, in relation to the growth of the arms and of the increase in functional capability. In the suckers, we analyzed the shedding mechanisms in the outer part of the infundibulum and described the outer and inner characteristics of the denticles, showing in detail their pore system, which is fundamental for their ability to explore the environment. These results are discussed by considering their possible application in the design of new octopus‐like artefacts, which will be able to take advantage of some of these ultrastructure characteristics and achieve advanced bioinspired functionalities. Microsc. Res. Tech. 78:1133–1145, 2015. © 2015 Wiley Periodicals, Inc.     

面向产品担保的集成管理研究

为了合理地制定企业的产品担保策略,构造了包括商业、技术和运作等企业内外各种要素的产品担保管理系统模型;提出了一个针对该系统的三层次集成管理框架,通过执行层的信息集成来综合商业、技术和运作等方面的数据,通过战术层的过程集成来并行处理不同阶段的工作,通过战术层的资源集成来构造多功能的开发团队和综合利用内外物流与服务资源,最后通过战略层的整体集成,在外部市场拉动和内部技术的推动下,不断调整产品寿命周期在不同阶段的产品担保策略。     

Dynamic axial crushing of short to long circular aluminium tubes with agglomerate cork filler

Cork is a complex natural cellular material with quite unknown or not well understood properties. It is available in the natural and in the agglomerate form and it is an ecological and very durable material. That is why it is used today as thermal and acoustic insulator, as a seal and as an energy-absorbing medium in flooring, shoes and packaging, among others. However, the application of agglomerate cork as filler inside structural thin-walled sections, in order to increase the energy absorption, has not been much explored. Dynamic experimental tests were carried out on empty and micro-agglomerate cork-filled tubes with 22 and 50 mm in internal diameter (D) and length (L), respectively, and numerical simulations were performed with the finite element method software LS-DYNA^TM, showing good agreement in terms of load–displacement curves and deformation patterns. Having validated the numerical model with experiments, the finite element model was used to undertake a systematic study of circular tubular structures impacted at 10 m/s. The load-deformation characteristics, energy-absorption response and collapse mode transitions of empty and cork-filled aluminium tubes with varying diameters and thicknesses (t), lengths of 25, 300 and 350 mm, but with constant slenderness ratios D/t and D/L were thus studied. Relevant comparisons were raised, showing that the slenderness ratios are very important parameters that globally govern the percentage increase in energy absorbed by tubular structures after cork-filling during an impact loading.     

基于杂散磁场感知与NBCNN-LSTM-Attention深度回归建模的永磁直线电机气隙磁密测量研究

本文提出一种基于隧道磁阻(TMR)传感器和噪声注入卷积神经网络(NBCNN)、长短期记忆网络(LSTM)、注意力机制动态集成神经网络预测模型(NBCNN-LSTM-Attention)的双边永磁同步直线电机气隙磁密新型非侵入式测量方法。首先，建立直线电机气隙磁场的解析模型和有限元模型作为数据基础，探寻直线电机的外部空间杂散磁场和内部中心气隙磁场存在非线性映射关系。其次，引入TMR传感器测量直线电机外部杂散磁场信号，并对传感器的安装位置进行优化，将内外一维磁密信号进行相似度特征匹配，以获取传感器最优测量位置。然后，将电机外部杂散磁场数据作为输入，内部气隙磁场数据作为输出，建立NBCNN-LSTM-Attention网络的内外磁场高精度映射模型，实现“用外代内”的非侵入式气隙磁密高精密测量。最后，搭建直线电机气隙磁密测量实验平台和高斯计对比测量实验平台，验证了本文所提方法的先进性和优越性。     

基于多代理的知识有色赋时Petri网的晶圆制造系统建模方法

为了对大规模、复杂的晶圆制造系统进行有效建模,提出了基于多代理的知识有色赋时Petri网的晶圆制造系统分层建模方法。在设备层,对晶圆制造系统的系统资源、内部行为和知识进行封装,建立了设备层代理模型。在设备组层和系统层,根据系统需求对各设备组内部及其之间的关系进行配置,分别建立了设备层和系统层代理模型。该方法提高了模型的可配置和重用性,降低了建模的复杂性,同时将知识与模型的库所和变迁集成,增强了模型的运行决策能力。通过上海某企业的150 mm晶圆的生产数据验证,证明了基于多代理的知识有色赋时Petri网的晶圆制造系统模型的有效性。     

多学科虚拟样机协同建模与仿真平台及其关键技术研究

针对面向多学科虚拟样机开发的协同建模与仿真平台,建立了其系统体系结构和技术体系结构。提出了该平台解决多学科虚拟样机协同建模与仿真问题中的4项关键技术,包括：①面向模型的多领域协同仿真技术;②基于系统工程理论和组件技术的建模技术;③网格技术和微软自动化技术;④采用可扩展标记语言和产品生命周期管理系统的集成技术。给出了一种符合并行工程思想的基于该平台的虚拟样机开发过程模型。最后,简要介绍了该平台在船舶领域的一个应用范例,以及在航天、船舶和卫星等领域的初步实践,表明该平台能有效支持虚拟样机工程。     

Machine path generation using direct slicing from design-by-feature solid model for rapid prototyping

This paper explains a new machine path generating system that its output is compatible with different rapid prototyping processes. The basis of this system is direct slicing from design-by-feature solid model. Slicing a computer-aided design (CAD) model through intersecting the model with the XY-plane at each Z increment is a well-known method of path generation. Slicing a CAD model is currently conducted through stereolithography (STL) file slicing, direct slicing, and additive direct slicing. A direct slicing approach inside a design-by-feature solid modeler is proposed. Autodesk Inventor solid modeler, as a design-by-feature solid modeler, is used for 3D solid modeling. The proposed system is implemented by Visual Basic codes inside Inventor. In this approach, first protrusion and subtractive features that form a model are extracted. Then, the intersection of each feature and the XY-plane is identified. Then, the internal and external loops are found. Depending on the specific rapid prototyping (RP) process requirements, internal or external hatch are also computed, respectively. Finally, a continuous path in required format is generated. The system reported in this paper has been successfully tested on several complex 3D models created in Inventor. The system offers customized output for different RP processes that need external or internal hatch pattern. The proposed approach for generating RP machine path through feature recognition inside design-by-feature solid modeler overcomes with the problems that are caused by imperfect STL files. Also, this system is capable of generating code compatible with major rapid prototyping processes.     

铁磁构件内外表面裂纹低频漏磁检测技术研究

针对承压设备中铁磁性构件内外壁损伤检测问题,发展了一种低频漏磁检测技术。对低频漏磁信号进行分析处理,提取出的低频漏磁信号的幅值和相位信息,用于铁磁构件内外表面损伤检测与定量评价。通过数值仿真和检测实验,研究了裂纹深度和位置(上表面或下表面)的裂纹对漏磁场特征参数空间分布的影响。结果表明,漏磁信号的幅值特征参数和相位特征参数均可用于铁磁性构件上下表面一定深度范围内裂纹检测及定量表征,但两个参数对不同位置及深度范围内裂纹检测的敏感性不同。当裂纹位于试件上表面时,幅值特征参数对裂纹深度变化更敏感;而当裂纹位于试件下表面时,相位特征参数对裂纹深度变化的敏感性更高。本文研究工作为承压设备中铁磁性构件内外壁损伤检测做了有益探索。     

可重构制造系统集成设计框架研究

提出了基于可重构制造单元的可重构制造系统集成设计框架.在该框架中,从规划和运行方面阐述了可重构制造系统的设计目标、设计流程及采用的关键技术,建立了支持可重构制造系统实施的计算机辅助设计系统的功能模型和体系结构,并讨论了系统的内部集成和外部集成问题.根据该设计框架,开发了集重构、布局规划、生产调度和仿真优化为一体的软件系统,该系统现已应用于航天、船舶和兵器部门.     

简易高精度的平面五点摄像机标定方法

为了进一步提高相机参数精度,简化标定过程,在张正友平面标定算法的基础上,提出了一种较简单的5点标定算法。本文利用一个矩形作为标定模板,将其4个角点和中心点作为待匹配点。仅利用不同角度拍摄的10(10~20幅均可)幅图像,即可求解全部相机内外参数。首先,为了减小数据对结果的影响,对获取的5个点的图像坐标进行归一化,将点坐标控制在以原点为中心,2~(1/2)为半径的圆内;其次,相机成像模型未考虑畸变,考虑到单应矩阵可能会有零元素,故按照9个自由度来求解;再次,求解出相机的内外参数,将求得结果的平均值作为非零因子λ的值;最后利用Levenberg Marquarat(LM)算法对所有内外参数进行整体优化。选用不同噪声水平的模拟实验和真实图像进行测试,结果显示该算法比张正友棋盘格算法的精度要高。     

Sensory structures on the antenna of soldier and worker castes of the termite species Odontotermes parvidens (Termitidae: Isoptera: Blattaria)

Odontotermes parvidens is a commonly found important pest species of termite that primarily feed on a range of cellulosic sources. In termites, communication among the nestmates is the basis of all their daily activities and the sensory structures present on the sensory appendages play a crucial role in different social behaviors perceiving and processing various signals of the nestmates and external environments. So, it is essential to understand in detail their sensory structures in order to understand the sensory system of the species O. parvidens. Thus, we have studied the antenna which is one of the primary sensory appendages of both soldier and worker individuals of the species to elucidate various antennal sensory structures and their distribution using scanning electron microscopy. Based on the morphological features of various sensilla, we observed seven types of sensilla as sensilla chaetica (subtypes I, II, III, and IV), sensilla trichodea (subtypes I and II), sensilla trichodea curvata (subtypes I and II), sensilla basiconica, sensilla capitula, Böhm bristles, and sensilla campaniformia (subtypes I and II) along with numerous glandular pores on the antenna of soldier and worker castes. We have also discussed the putative functions of all the sensilla observed based on their external morphology and distributional characteristics on the antenna of soldier and worker castes of the species O. parvidens. Furthermore, the abundance of sensillar types on the antenna of both the castes has also been discussed.     

Numerical simulation of the transient cavitating turbulent flows around the Clark-Y hydrofoil using modified partially averaged Navier-Stokes method

This paper presents the implementation and assessment of a modified Partially averaged Navier-Stokes (PANS) turbulence model which can successfully predict the transient cavitating turbulent flows. The proposed model treats the standard k-ε model as the parent model, and its main distinctive features are to (1) formulate the unresolved-to-total kinetic energy ratio (f _k ) based on the local grid size as well as turbulence length scale, and (2) vary the f _k -field both in space and time. Numerical simulation used the modified PANS model for the sheet/cloud cavitating flows around a three-dimensional Clark-Y hydrofoil. The available experimental data and calculations of the standard k-ε model, the f _k = 0.8 PANS model, the f _k = 0.5 PANS model are also provided for comparisons. The results show that the modified PANS model accurately captures the transient cavitation features as observed in experiments, namely, the attached sheet cavity grows in the flow direction until to a maximum length and then it breaks into a highly turbulent cloud cavity with three-dimensional structures in nature. Time-averaged drag/lift coefficients together with the streamwise velocity profiles predicted by the proposed model are in good agreement with the experimental data, and improvements are shown when compared with results of the standard k-ε model, the f _k = 0.8 PANS model and the f _k = 0.5 PANS model. Overall, the modified PANS model shows its encouraging capability of predicting the transient cavitating turbulent flows.

     

Evaluation of contrasting techniques for X‐ray imaging of velvet worms (Onychophora)

Non‐invasive imaging techniques like X‐ray computed tomography have become very popular in zoology, as they allow for simultaneous imaging of the internal and external morphology of organisms. Nevertheless, the effect of different staining approaches required for this method on samples lacking mineralized tissues, such as soft‐bodied invertebrates, remains understudied. Herein, we used synchrotron radiation‐based X‐ray micro‐computed tomography to compare the effects of commonly used contrasting approaches on onychophorans – soft‐bodied invertebrates important for studying animal evolution. Representatives of Euperipatoides rowelli were stained with osmium tetroxide (vapour or solution), ruthenium red, phosphotungstic acid, or iodine. Unstained specimens were imaged using both standard attenuation‐based and differential phase‐contrast setups to simulate analyses with museum material. Our comparative qualitative analyses of several tissue types demonstrate that osmium tetroxide provides the best overall tissue contrast in onychophorans, whereas the remaining staining agents rather favour the visualisation of specific tissues and/or structures. Quantitative analyses using signal‐to‐noise ratio measurements show that the level of image noise may vary according to the staining agent and scanning medium selected. Furthermore, box‐and‐whisker plots revealed substantial overlap in grey values among structures in all datasets, suggesting that a combination of semiautomatic and manual segmentation of structures is required for comprehensive 3D reconstructions of Onychophora, irrespective of the approach selected. Our results show that X‐ray micro‐computed tomography is a promising technique for studying onychophorans and, despite the benefits and disadvantages of different staining agents for specific tissues/structures, this method retrieves informative data that may eventually help address evolutionary questions long associated with Onychophora.     

Prognostic model for prostate cancer based on glycolysis-related genes and non-negative matrix factorization analysis

Background: Establishing an appropriate prognostic model for PCa is essential for its effective treatment. Glycolysis is a vital energy-harvesting mechanism for tumors. Developing a prognostic model for PCa based on glycolysis-related genes is novel and has great potential. Methods: First, gene expression and clinical data of PCa patients were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), and glycolysis-related genes were obtained from the Molecular Signatures Database (MSigDB). Gene enrichment analysis was performed to verify that glycolysis functions were enriched in the genes we obtained, which were used in non-negative matrix factorization (NMF) to identify clusters. The correlation between clusters and clinical features was discussed, and the differentially expressed genes (DEGs) between the two clusters were investigated. Based on the DEGs, we investigated the biological differences between clusters, including immune cell infiltration, mutation, tumor immune dysfunction and exclusion, immune function, and checkpoint genes. To establish the prognostic model, the genes were filtered based on univariable Cox regression, LASSO, and multivariable Cox regression. Kaplan–Meier analysis and receiver operating characteristic analysis validated the prognostic value of the model. A nomogram of the risk score calculated by the prognostic model and clinical characteristics was constructed to quantitatively estimate the survival probability for PCa patients in the clinical setting. Result: The genes obtained from MSigDB were enriched in glycolysis functions. Two clusters were identified by NMF analysis based on 272 glycolysis-related genes, and a prognostic model based on DEGs between the two clusters was finally established. The prognostic model consisted of LAMPS, SPRN, ATOH1, TANC1, ETV1, TDRD1, KLK14, MESP2, POSTN, CRIP2, NAT1, AKR7A3, PODXL, CARTPT, and PCDHGB2. All sample, training, and test cohorts from The Cancer Genome Atlas (TCGA) and the external validation cohort from GEO showed significant differences between the high-risk and low-risk groups. The area under the ROC curve showed great performance of this prognostic model. Conclusion: A prognostic model based on glycolysis-related genes was established, with great performance and potential significance to the clinical application.     

基于分布式认知的人机交互资源模型

为协调人机交互中的信息需求和资源操作,综合分析了认知过程中的内外表征,提出一种基于分布式认知的资源模型.该模型用信息结构定义和组织各类信息资源,用交互策略配置资源的使用流程,并用智能体描述建模方法和实施策略.通过交互流程和用户界面,实现认知的外部化和表面化,降低了用户在人机交互中的认知负荷.通过一个计算机辅助手机键盘配色原型系统,验证了该模型在实际应用中的实用性与有效性.     

Embossed‐carving processing of cytoskeletons of cultured cells by using focused ion beam technology

The focused ion beam (FIB) technology has drawn considerable attention in diverse research fields. FIB can be used to mill samples at the nanometer scale by using an ion beam derived from electrically charged liquid gallium (Ga). This powerful technology with accuracy at the nanometer scale is now being applied to life science research. In this study, we show the potential of FIB as a new tool to investigate the internal structures of cells. We sputtered Ga⁺ onto the surface or the cross section of animal cells to emboss the internal structures of the cell. Ga⁺ sputtering can erode the cell surface or the cross section and thus emboss the cytoskeletons quasi‐3 dimensionally. We also identified the embossed structures by comparing them with fluorescent images obtained via confocal laser microscopy because the secondary ion micrographs did not directly provide qualitative information directly. Furthermore, we considered artifacts during the FIB cross sectioning of cells and propose a way to prevent undesirable artifacts. We demonstrate the usefulness of FIB to observe the internal structures of cells. Microsc. Res. Tech. 76:290–295, 2013. © 2013 Wiley Periodicals, Inc.     

COMBINING INTERNAL AND EXTERNAL ROBOT MODELS FOR IMPROVED MODEL PARAMETER ESTIMATION

Experimental robot identification techniques can principally be divided into two categories, based on the type of models they use : internal or external. Internal models relate the joint torques or forces and the motion of the robot; external models relate the reaction forces and torques on the bedplate and the motion data. This paper describes how internal and external robot models can be combined into one identifiable minimal model. This model allows to combine joint torque/force and reaction torque/force measurements in one parameter estimation scheme. This combined model estimation will yield more accurate parameter estimates, and consequently better actuator torque predictions, which is shown by means of a simulated experiment on an industrial robot (KUKA IR 361). This increased accuracy is quite interesting in view of using advanced control algorithms such as computed torque control.