Unraveling Membrane Perturbations Caused by the Bacterial Riboregulator Hfq

Hfq is a pleiotropic regulator that mediates several aspects of bacterial RNA metabolism. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, usually via its interaction with small regulatory RNAs. Previously, we showed that the Hfq C-terminal region forms an amyloid-like structure and that these fibrils interact with membranes. The immediate consequence of this interaction is a disruption of the membrane, but the effect on Hfq structure was unknown. To investigate details of the mechanism of interaction, the present work uses different in vitro biophysical approaches. We show that the Hfq C-terminal region influences membrane integrity and, conversely, that the membrane specifically affects the amyloid assembly. The reported effect of this bacterial master regulator on membrane integrity is discussed in light of the possible consequence on small regulatory RNA-based regulation.     

Bile Acid–Drug Interaction via Organic Anion-Transporting Polypeptide 4C1 Is a Potential Mechanism of Altered Pharmacokinetics of Renally Excreted Drugs

Patients with liver diseases not only experience the adverse effects of liver-metabolized drugs, but also the unexpected adverse effects of renally excreted drugs. Bile acids alter the expression of renal drug transporters, however, the direct effects of bile acids on drug transport remain unknown. Renal drug transporter organic anion-transporting polypeptide 4C1 (OATP4C1) was reported to be inhibited by chenodeoxycholic acid. Therefore, we predicted that the inhibition of OATP4C1-mediated transport by bile acids might be a potential mechanism for the altered pharmacokinetics of renally excreted drugs. We screened 45 types of bile acids and calculated the IC₅₀, K_i values, and bile acid–drug interaction (BDI) indices of bile acids whose inhibitory effect on OATP4C1 was >50%. From the screening results, lithocholic acid (LCA), glycine-conjugated lithocholic acid (GLCA), and taurine-conjugated lithocholic acid (TLCA) were newly identified as inhibitors of OATP4C1. Since the BDI index of LCA was 0.278, LCA is likely to inhibit OATP4C1-mediated transport in clinical settings. Our findings suggest that dose adjustment of renally excreted drugs may be required in patients with renal failure as well as in patients with hepatic failure. We believe that our findings provide essential information for drug development and safe drug treatment in clinics.     

误差反向传播算法的数学推导及实现步骤

提供了人工神经网络的一种算法-误差反向传播算法的数学推导方法及上机实现步骤.     

基于虚拟实景和Perl的火电厂教学系统

基于静态图像的虚拟现实技术是一种提供初步VR体验的虚拟现实技术。针对火电厂多媒体教学,介绍了基于该技术的工作原理、基本特色、开发系统的组成及其在火电厂多媒体远程教学中的典型应用。同时为系统增添了简单实用的教学搜索。     

基于极端学习机的MANET移动性预测模型

针对移动自组织网络移动性在管理无线网络带宽资源可用性方面的重要性,为了更好地规划连续服务可用性和有效能源管理以提升网络的整体服务质量,提出了一种基于极端学习机的MANET移动性预测模型。利用ELM对MANET中的任意节点进行建模;假设已知每个移动节点当前的移动性信息（位置、速度和运动方向角度）,以这种方式预测节点未来的位置和相邻节点之间未来的距离;基于几个标准移动性模型,产生更加真实、精确的移动性预测,从而更好地捕捉任意节点直角坐标系之间现有交互/相关性。使用标准移动性模型的仿真结果验证了所提模型的有效性,实验结果表明,提出的预测模型明显改进了传统基于多层感知器的模型,此外,当预测相邻节点之间未来距离时,避免了当前算法对预测精度的限制。     

神经元网络场电位的迭代学习控制研究

基于映射神经元模型和Hindmarsh-Rose神经元模型构建小世界神经网络,并施加带有遗忘因子的迭代学习控制算法,以实现神经网络的同步控制。仿真结果表明迭代学习控制同时适用于离散的和连续的神经网络模型,可以实现神经网络同步和去同步状态的相互转化,其优势在于随着迭代次数的增加,控制信号强度逐渐减弱,从而保持神经元本身的放电特性不变。所得结果为将非线性控制理论应用于帕金森等神经疾病控制提供了新思路。     

Enhancing 5th graders’ science content knowledge and self-efficacy through game-based learning

Many argue that games can positively impact learning by providing an intrinsically motivating and engaging learning environment for students in ways that traditional school cannot. Recent research demonstrates that games have the potential to impact student learning in STEM content areas and that collaborative gameplay may be of particular importance for learning gains. This study investigated the effects of collaborative and single game player conditions on science content learning and science self-efficacy. Results indicated that there were no differences between the two playing conditions; however, when conditions were collapsed, science content learning and self-efficacy significantly increased. Future research should focus on the composition of collaboration interaction among game players to assess what types of collaborative tasks may yield positive learning gains.     

数据缺失下学习贝叶斯网的SEM算法

针对SEM算法易收敛于局部最优的问题,提出一种改进SEM算法——DSEM-PACOB算法,采用PACOB算法提供的良好候选网络及合理的策略,估计节点变量缺失值,并使与待估节点变量紧密相关的若干节点变量直接参与估计。实验结果表明,与SEM算法相比,利用新算法获得的最终解的质量有所提高,且具有更好的稳定性。     

灰色偏相关评价法在认知型学生模型中的应用

针对认知能力评价这类因素较多,且难以进行定量描述的问题,建立认知能力因素评价体系,利用灰色偏相关评价法建立认知型学生模型。首先分析各认知能力因素的相互影响关系,计算偏相关系数得到各认知能力因素的权重值。然后确定评价灰类,建立白化权函数,得到各认知能力因素关于各评价灰类的灰色评价权值,从而建立认知型学生综合评价模型。最后通过实例对方法模型进行验证。实例表明,该方法模型能够对学生知识水平作出评价并引导学生进行学习,其结果具有一定的可靠性。