Human-Induced Neural and Mesenchymal Stem Cell Therapy Combined with a Curcumin Nanoconjugate as a Spinal Cord Injury Treatment

We currently lack effective treatments for the devastating loss of neural function associated with spinal cord injury (SCI). In this study, we evaluated a combination therapy comprising human neural stem cells derived from induced pluripotent stem cells (iPSC-NSC), human mesenchymal stem cells (MSC), and a pH-responsive polyacetal–curcumin nanoconjugate (PA-C) that allows the sustained release of curcumin. In vitro analysis demonstrated that PA-C treatment protected iPSC-NSC from oxidative damage in vitro, while MSC co-culture prevented lipopolysaccharide-induced activation of nuclear factor-κB (NF-κB) in iPSC-NSC. Then, we evaluated the combination of PA-C delivery into the intrathecal space in a rat model of contusive SCI with stem cell transplantation. While we failed to observe significant improvements in locomotor function (BBB scale) in treated animals, histological analysis revealed that PA-C-treated or PA-C and iPSC-NSC + MSC-treated animals displayed significantly smaller scars, while PA-C and iPSC-NSC + MSC treatment induced the preservation of β-III Tubulin-positive axons. iPSC-NSC + MSC transplantation fostered the preservation of motoneurons and myelinated tracts, while PA-C treatment polarized microglia into an anti-inflammatory phenotype. Overall, the combination of stem cell transplantation and PA-C treatment confers higher neuroprotective effects compared to individual treatments.     

V形件弯曲凹模最小深度的确定

该文指出了目前广泛使用的经验查表法确定V形件弯曲凹模深度的不合理性，分析了凹模斜壁的作用及其与圆角半径的相互关系，提出了凹模最小的深度的概念和计算公式。     

Electrochemical characteristics for redox systems at nano-honeycomb diamond

Electrochemical characteristics for several redox systems at diamond films with highly ordered nanometer-scale cylindrical pores (‘nano-honeycombs’) were examined with cyclic voltammetry (CV) and electrochemical impedance measurements. The cyclic voltammetric anodic-cathodic peak separations for these nano-honeycomb electrodes were in the same range as those for polished polycrystalline diamond films, indicating that the involvement of the oxygen-terminated surface of the nano-pore walls, which should give rise to large peak separations for certain redox couples was only slight. Moreover, the peak currents in the CV were not enhanced to the extent expected on the basis of the roughness factors of the nano-honeycomb films. Ac impedance plots results indicated the existence of a concentration gradient of the reactant in the nano-pores, which is in agreement with theoretical predictions for charge transfer reactions in porous electrodes. The average concentration of the reactant (Fe^2+/3+) inside the nano-pores was a factor of ca. 80 lower than that in the bulk electrolyte. The results of the impedance analysis also indicated an increase in the reaction resistances with decreasing pore diameters.     

薄板坯连铸浸入式水口结构数值模拟

使用有限元计算方法开展薄板坯连铸浸入式水口流场的研究 ,分别对水口不同浸入深度的流场分布、水口出口不同角度的流场分布进行计算。结果发现 :水口的浸入深度在 30 0mm时较为合理 ;水口的出口角度以R1 5、60°、45°为宜     

基于GPGPU的实体表面实时提取

为实时提取三维实体表面,提出一种基于GPGPU并行计算的实体表面实时提取方法。在分析深度剥离算法原理和GPU图形绘制管线的基础上,给出在GPU上利用深度剥离算法实现实时提取三维实体表面的算法;通过OpenGL的高级着色语言GLSL控制GPU的图形绘制管线实现了该算法,给出其伪代码。以龙、叶轮和刀具扫描体的模型为应用实例验证了该算法效果良好,特别是对于刀具扫描体表面的提取,可满足实时性要求。     

改进的蒽酮法检测肺炎链球菌荚膜多糖结合物中多糖浓度

目的改进检测肺炎链球菌荚膜多糖结合物中多糖浓度的蒽酮法。方法分别对蒽酮法中蒽酮的浓度和处理温度进行优化,并对改进的方法进行验证和重复性检测。结果适宜的蒽酮浓度为0·3g/300ml,处理温度为40℃,在检测肺炎链球菌多糖结合物原液中的多糖浓度时,标准曲线回归系数高,方法稳定,重现性好。结论改进的蒽酮法可以有效、准确、稳定地检测肺炎链球菌结合物多糖原液中的多糖浓度。     

考虑土体强度参数深度依赖性的非平稳随机场边坡滑动深度和体积分析

基于随机有限元方法（RFEM）和Monte-Carlo模拟,建立了能够模拟具有深度依赖性的土体强度参数边坡或具有软弱夹层边坡的非平稳随机场模型。通过辐射扫描方法获取最危险滑动面,得到非平稳随机场边坡滑动深度和滑动体积。将该方法与均质边坡和平稳随机场边坡获得的滑动深度和滑动体积进行对比,研究土体强度参数深度依赖性的非平稳随机场边坡的不同坡度和各向异性对滑动深度和滑动体积的影响。结果表明：基于RFEM的非平稳随机场滑动深度和滑动体积结果为地质灾害风险及后果评估提供了一个参考分析的新角度;参数的深度依赖性程度越高(变化率b越大),则边坡平均滑动深度和滑动体积越小;在大坡度滑坡风险后果评估中,可以基于均质边坡分析结果进行初步预估;在非平稳随机场中,随着各向异性的增大,所有坡度边坡的滑动体积变异系数增大;不同坡度下,水平方向的相关程度越大,则土坡内软弱夹层的不确定性越强,滑动体积的变异系数也不断增大。     

Order-k α-hulls and α-shapes

We introduce order-k α-hulls and α-shapes – generalizations of α-hulls and α-shapes. Being also a generalization of k-hull (known in statistics as “k-depth contour”), order-k α-hull provides a link between shape reconstruction and statistical depth. As a generalization of α-hull, order-k α-hull gives a robust shape estimation by ignoring locally up to k outliers in a point set. Order-k α-shape produces an “inner” shape of the set, with the amount of “digging” into the points controlled by k. As a generalization of k-hull, order-k α-hull is capable of determining “deep” points amidst samples from a multimodal distribution: it correctly identifies points which lie outside clusters of samples.The order-k α-hulls and α-shapes are related to order-k Voronoi diagrams in the same way in which α-hulls and α-shapes are related to Voronoi diagrams. This implies that order-k α-hull and α-shape can be readily built from order-k Voronoi diagram, and that the number of different order-k α-shapes for all possible values of α is proportional to the complexity of order-k Voronoi diagram.     

Bayesian estimation of Dirichlet mixture model with variational inference

In statistical modeling, parameter estimation is an essential and challengeable task. Estimation of the parameters in the Dirichlet mixture model (DMM) is analytically intractable, due to the integral expressions of the gamma function and its corresponding derivatives. We introduce a Bayesian estimation strategy to estimate the posterior distribution of the parameters in DMM. By assuming the gamma distribution as the prior to each parameter, we approximate both the prior and the posterior distribution of the parameters with a product of several mutually independent gamma distributions. The extended factorized approximation method is applied to introduce a single lower-bound to the variational objective function and an analytically tractable estimation solution is derived. Moreover, there is only one function that is maximized during iterations and, therefore, the convergence of the proposed algorithm is theoretically guaranteed. With synthesized data, the proposed method shows the advantages over the EM-based method and the previously proposed Bayesian estimation method. With two important multimedia signal processing applications, the good performance of the proposed Bayesian estimation method is demonstrated.     

泄水建筑物下游冲刷坑二维数值模拟

对巨亭水电站泄水建筑物下游局部冲刷过程进行了二维数值模拟。采用RNG k-ε湍流模型封闭N-S方程、有限体积法在计算网格上离散求解、VOF方法追踪自由水面;采用C语言编写用户自定义函数,以泥沙起动切应力作为床面泥沙起动判别标准,通过分析比较水流剪切力与泥沙起动切应力大小,用以控制冲刷坑底部边界变化;采用局部重构模型和弹簧光顺模型更新计算区域和网格质量,藉以模拟和追踪局部冲刷坑边界变化。研究表明,模拟结果与实测资料符合良好。在冲刷坑的冲刷过程中,床面剪切应力随着冲刷的进程急剧减小,湍动能随着冲刷的进程减小缓慢;床面剪切应力和湍动能沿程变化均较为剧烈,床面剪切应力沿程先增大后减小,床面湍动能则沿程减小。冲刷坑的纵向平衡形态或床面泥沙起动主要决定于床面剪切应力,床面湍动能对泥沙起动也具有重要影响。