基于梯度树的光学层析正则化重建

光学层析成像是一个病态重建过程,为降低重建过程中的病态特性,需加入合适的先验信息。目前,大多数重建都是基于扩散方程的,在某些情况下,这种重建会失败。直接基于玻耳兹曼传输模型,并以图像熵为正则化项的梯度迭代重建是一种有效的方法。该方法中,梯度计算是个难点。对此,提出一种基于梯度树的求解方法,降低光学层析图像重建的病态性,有效地重建光学层析图像。     

MiR-320-3p Regulates the Proliferation and Differentiation of Myogenic Progenitor Cells by Modulating Actin Remodeling

Skeletal myogenesis is essential for the maintenance of muscle quality and quantity, and impaired myogenesis is intimately associated with muscle wasting diseases. Although microRNA (miRNA) plays a crucial role in myogenesis and relates to muscle wasting in obesity, the molecular targets and roles of miRNAs modulated by saturated fatty acids (SFA) are largely unknown. In the present study, we investigated the role of miR-320-3p on the differentiation of myogenic progenitor cells. Palmitic acid (PA), the most abundant dietary SFA, suppressed myogenic factors expression and impaired differentiation in C2C12 myoblasts, and these effects were accompanied by CFL2 downregulation and miR-320-3p upregulation. In particular, miR-320-3p appeared to target CFL2 mRNA directly and suppress the expression of CFL2, an essential factor for filamentous actin (F-actin) depolymerization. Transfection of myoblasts with miR-320-3p mimic increased F-actin formation and nuclear translocation of Yes-associated protein 1 (YAP1), a key component of mechanotransduction. Furthermore, miR-320-3p mimic increased myoblast proliferation and markedly impeded the expression of MyoD and MyoG, consequently inhibiting myoblast differentiation. In conclusion, our current study highlights the role of miR-320-3p on CFL2 expression, YAP1 activation, and myoblast differentiation and suggests that PA-inducible miR-320-3p is a significant mediator of muscle wasting in obesity.     

Biophysical Modulation of Mesenchymal Stem Cell Differentiation in the Context of Skeletal Repair

A prominent feature of the skeleton is its ability to remodel in response to biophysical stimuli and to repair under varied biophysical conditions. This allows the skeleton considerable adaptation to meet its physiological roles of stability and movement. Skeletal cells and their mesenchymal precursors exist in a native environment rich with biophysical signals, and they sense and respond to those signals to meet organismal demands of the skeleton. While mechanical strain is the most recognized of the skeletal biophysical stimuli, signaling phenomena also include fluid flow, hydrostatic pressure, shear stress, and ion-movement-related electrokinetic phenomena including, prominently, streaming potentials. Because of the complex interactions of these electromechanical signals, it is difficult to isolate the significance of each. The application of external electrical and electromagnetic fields allows an exploration of the effects of these stimuli on cell differentiation and extra-cellular matrix formation in the absence of mechanical strain. This review takes a distinctly translational approach to mechanistic and preclinical studies of differentiation and skeletal lineage commitment of mesenchymal cells under biophysical stimulation. In vitro studies facilitate the examination of isolated cellular responses while in vivo studies permit the observation of cell differentiation and extracellular matrix synthesis.     

一种基于计算机的白血病细胞治疗效果数学模型

根据熵值在生物系统中的应用原理,改建一种可用计算机模拟的白血病细胞药物治疗效果的数学模型,并应用于新型诱导分化剂氨基甾体对K562白血病细胞的作用中.结果表明药物作用后细胞系统的熵值增加,良好的药物取决于降低癌基因表达率,升高诱导分化率,以致抑制白血病细胞的增殖.该模型亦可用于其他抗癌药物治疗效果的计算机模拟.     

基于基因打靶技术的中医脏腑辨证分型算法

受生物学基因打靶技术的启发和通过对中医脏腑证型分类标准的研究,提出了一种新颖的中医智能脏腑辨证算法,称之为中医脏腑辨证分型算法。主要思想是把中医脏腑证型的主要症状和次要症状,以及舌象、脉象信息设计为脏腑证型模靶;临床病例病症信息作为脏腑病症基因组,并进行模靶射击式的辨证分型操作。通过对慢性胃炎疾病的辨证分型计算结果的分析,说明中医脏腑辨证分型算法的有效性,为中医辨证信息处理的客观化、可计算化提供了一种新的研究方法,同时具有一定的临床诊断应用价值。     

基于查询向量的英语话题跟踪研究

通过分析英语新闻报道的特点,提出了一种基于词汇区分和位置特征相结合的特征项抽取算法.词汇区分是指将单词分为首字母是大写的单词和首字母不是大写的单词,位置特征利用新闻报道的倒金字塔式的结构特点决定单词的重要性.提出了一种基于多个特征项抽取算法融合的特征项权值计算方法,该方法认为被越多的特征项抽取算法选中的特征项越重要.提出了一种基于多数投票策略的双重过滤算法,对报道和话题是否相关进行两次过滤,大大降低了系统的误报率.实验表明提出的3种算法不但取得了很好的效果,而且具有很好的可扩展性.     

矿山岩体破坏微震分异速率特征及预警研究

在矿山岩体破坏预警研究中,探究岩体损伤特征规律及给出具体预警参数值对保障矿山安全至关重要。本文以某金属矿山为例,基于微震监测技术建立地压监测系统,结合该矿山某次顶板大范围冒落事件,采用主成分分析法确定最佳统计时间窗口,对顶板冒落事件前后微震时空演化特征进行分析。分析表明微震事件密度云图中心位置与破坏位置相一致,在岩体破坏前微震数量有持续增多,达到峰值后又迅速下降的前兆信息。以微震数量方差表示微震分异程度,以此表征岩体受损程度,采用有限差分法得出微震事件分异速率指标,研究表明岩体破坏过程微震分异速率分为稳定分异阶段、加速分异阶段和岩体破坏3个阶段。稳定分异阶段分异速率呈正态分布,采用Gauss Amp函数对其进行拟合,最终得出置信度为0.99的将区间上限0.306确定为分异速率预警值。该研究为采用微震监测技术的矿山灾害预警系统建立提供理论基础,对矿山安全生产管理具有一定借鉴意义。     

基于数值微分核脉冲信号数字处理方法

核反应堆核测量系统测量探测器输出的核脉冲信号,该信号后沿拖尾很长,在计数率较高时容易产生信号堆积和基线漂移等问题,导致源区计数率测量上限仅能达到10⁵ Hz左右。文中基于数值微分方法,采用数字处理技术,在时域上分析了核脉冲信号经过前置放大、信号成形、低通滤波和脉冲甄别后的输出,并利用探测器实测信号进行了仿真。仿真结果表明,基于数值微分的数字处理方法可以实现相邻0.4μs脉冲信号的识别和测量,将源区测量计数率上限提升到2×10⁶ Hz以上。     

Heat Shock Alters the Proteomic Profile of Equine Mesenchymal Stem Cells

The aim of this research was to determine the impact of heat stress on cell differentiation in an equine mesenchymal stem cell model (EMSC) through the application of heat stress to primary EMSCs as they progressed through the cell specialization process. A proteomic analysis was performed using mass spectrometry to compare relative protein abundances among the proteomes of three cell types: progenitor EMSCs and differentiated osteoblasts and adipocytes, maintained at 37 °C and 42 °C during the process of cell differentiation. A cell-type and temperature-specific response to heat stress was observed, and many of the specific differentially expressed proteins were involved in cell-signaling pathways such as Notch and Wnt signaling, which are known to regulate cellular development. Furthermore, cytoskeletal proteins profilin, DSTN, SPECC1, and DAAM2 showed increased protein levels in osteoblasts differentiated at 42 °C as compared with 37 °C, and these cells, while they appeared to accumulate calcium, did not organize into a whorl agglomerate as is typically seen at physiological temperatures. This altered proteome composition observed suggests that heat stress could have long-term impacts on cellular development. We propose that this in vitro stem cell culture model of cell differentiation is useful for investigating molecular mechanisms that impact cell development in response to stressors.