血管内皮生长因子结合可降解壳聚糖治疗大鼠心肌梗塞的研究

摘要:目的 研 究 血 管 内 皮 生 长 因 子 ( vascular endothelial growth factor, VEGF ) 结 合 可 降 解 壳 聚 糖 ( degradablechitosan,DC)对心肌梗塞大鼠的治疗作用。 方法 将 32 只 SD 大鼠随机分为假手术组、模型组、VEGF 组和 VEGF+ DC 组,每组 8 只。 4 组大鼠均采用结扎冠状动脉左前降支的方法进行造模,其中假手术组只穿线不结扎。 造模后, 向模型组大鼠心肌注射 100 μL 生理盐水,VEGF 组大鼠于同一位置注射同体积 VEGF 溶液,VEGF+DC 组大鼠注射 VEGF+DC 溶液。 造模 4 周 后,对 所 有 实 验 大 鼠 进 行 超 声 心 功 能 检 测,考 察 左 心 室 收 缩 期 及 舒 张 期 前 壁 厚 度( LVAW;s 和 LVAW;d) 、左心室收缩期及舒张期内径( LVID;s 和 LVID;d) 、左心室收缩期及舒张期容积( LV Vol;s 和 LV Vol;d) 、左室射血分数( EF% )及短轴缩短率( FS% ) ,血流动力学考察左室舒张末压( EDP ) 和等容收缩期及 舒张期左心室内压力上升最大速率( + dp / dt 和 - dp / dt) ,计算左心室指数( LVM / BW) 并对心肌进行苏木素-伊红 ( HE)染色观察各组实验大鼠心肌病理变化。 结果 VEGF 组和 VEGF+DC 组大鼠的心肌梗塞均得到有效改善,其 中 VEGF+DC 组的改善作用更加显著。 结论 VEGF 结合 DC 对心肌梗塞大鼠的心功能具有改善作用,具有一定的治疗作用。     

自适应跌倒前实时检测方法

为了能利用单一传感器在跌倒撞击前实时检测出跌倒即将发生,结合支持向量机(SVM)和阈值法设计了一种自适应跌倒前实时检测方法.实验结果表明,该方法能在跌倒撞击前实时检测出跌倒即将发生,且比人工阈值法和SVM方法有更长的间隔时间,比SVM方法有更高的召回率和特异度.     

基于差异信息量的多源数据融合方法

D-S证据理论可应用于多源数据融合领域，但在处理高度冲突的证据时，可能会出现反直觉的结果.为解决这一问题，本文提出了差异信息量的概念及融合方法.首先，通过信息熵表明证据的相对重要性，采用散度获取证据可信度.然后利用证据可信度优化证据差异度以得到差异信息量，经过计算获取数据的最终权重，并将其作为D-S证据理论中的基本概率分配进行决策.在处理冲突证据、一致证据及不同数量证据等方面的数据融合问题时与其他方法对比，所提方法收敛更快，准确度更高.故障诊断的应用实例表明，所提方法的不确定性更小，优于现存的其他方法.     

全球大地震破裂空间复杂度特征研究

基于有限断层反演得到的滑移数据, 用独立滑移单元的数量表征地震破裂复杂度, 据此对大地震破裂进行分组, 并研究破裂复杂度与主要震源参数之间的关系, 探讨破裂复杂度的全球及区域空间分布特征。结果表明, 矩震级很大(Mw ≥ 8.5)的事件, 地震破裂复杂度更大; 破裂复杂度较高的地震分布在浅层地壳(≤ 30 km)内的概率最大, 随着震源深度增加, 破裂复杂度对震源深度的敏感性逐渐消失; 走滑断层机制占比较大的事件, 破裂复杂度较高; 破裂复杂度与地震能矩比没有明确的关系; 破裂复杂度的空间分布特征与区域地质构造环境相关。破裂复杂度的空间分布特征可以分为3类, 第一类是板块之间简单碰撞产生的俯冲带, 板块交界处的滑动速率和方向较为一致, 这种情形下以比较简单的事件类型为主; 第二类是多板块交界处, 或者板块交界处的滑动速率和方向在整个区域内存在差异; 第三类是大陆内部的强烈挤压地带。与第一类空间分布特征相比, 第二类和第三类情形下破裂复杂度相对更高。地震破裂复杂度可以在一定程度上反映区域应力场的复杂性。     

多弧离子镀制备的耐事故燃料包壳铬涂层晶粒结构研究

本文通过从几十微米到几埃的多尺度表征展示了多弧离子镀制备铬涂层的详细结构.经XRD, SEM, FIB, TEM和HRTEM表征，结果显示该涂层是一种多重结构，包括表面上的微米级颗粒、缺陷带钉扎的微米或次微米级液滴、以堆垛层错为晶界的柱状晶、以刃位错和螺型位错为区分的微晶、位错末端的原子畸变以及原子排列无序化的区域.这些结构通过改变涂层的结晶度，影响了晶格常数、表面粗化和FIB溅射裂纹.此外，通过分析HTEM照片，确定了这些堆垛层错和位错的类型.最后，讨论了沉积参数对这些晶粒结构的影响.     

Molecular function of the novel α7β2 nicotinic receptor

The α7 nicotinic receptor is a promising drug target for neurological and inflammatory disorders. Although it is the homomeric member of the family, a novel α7β2 heteromeric receptor has been discovered. To decipher the functional contribution of the β2 subunit, we generated heteromeric receptors with fixed stoichiometry by two different approaches comprising concatenated and unlinked subunits. Receptors containing up to three β2 subunits are functional. As the number of β2 subunits increases in the pentameric arrangement, the durations of channel openings and activation episodes increase progressively probably due to decreased desensitization. The prolonged activation episodes conform the kinetic signature of α7β2 and may have an impact on neuronal excitability. For activation of α7β2 receptors, an α7/α7 binding-site interface is required, thus indicating that the three β2 subunits are located consecutively in the pentameric arrangement. α7-positive allosteric modulators (PAMs) are emerging as novel therapeutic drugs. The presence of β2 in the pentamer affects neither type II PAM potentiation nor activation by an allosteric agonist whereas it impairs type I PAM potentiation. This first single-channel study provides fundamental basis required to decipher the role and function of the novel α7β2 receptor and opens doors to develop selective therapeutic drugs.     

Macropinocytosis,mTORC1 and cellular growth control

The growth and proliferation of metazoan cells are driven by cellular nutrient status and by extracellular growth factors. Growth factor receptors on cell surfaces initiate biochemical signals that increase anabolic metabolism and macropinocytosis, an actin-dependent endocytic process in which relatively large volumes of extracellular solutes and nutrients are internalized and delivered efficiently into lysosomes. Macropinocytosis is prominent in many kinds of cancer cells, and supports the growth of cells transformed by oncogenic K-Ras. Growth factor receptor signaling and the overall metabolic status of the cell are coordinated in the cytoplasm by the mechanistic target-of-rapamycin complex-1 (mTORC1), which positively regulates protein synthesis and negatively regulates molecular salvage pathways such as autophagy. mTORC1 is activated by two distinct Ras-related small GTPases, Rag and Rheb, which associate with lysosomal membranes inside the cell. Rag recruits mTORC1 to the lysosomal surface where Rheb directly binds to and activates mTORC1. Rag is activated by both lysosomal luminal and cytosolic amino acids; Rheb activation requires phosphoinositide 3-kinase, Akt, and the tuberous sclerosis complex-1/2. Signals for activation of Rag and Rheb converge at the lysosomal membrane, and several lines of evidence support the idea that growth factor-dependent endocytosis facilitates amino acid transfer into the lysosome leading to the activation of Rag. This review summarizes evidence that growth factor-stimulated macropinocytosis is essential for amino acid-dependent activation of mTORC1, and that increased solute accumulation by macropinocytosis in transformed cells supports unchecked cell growth.     

A Method to Visualize the Skeleton Industrial Structure with Input-Output Analysis and Its Application in China,Japan and USA

The paper established a double filtering method (DFM) to visualize the skeleton industrial structure (SIS) of one economy and find its evolution rule. Different with the previous researches, this method is from a new view of industrial conjunctions combined by leading sectors to depict the industrial structure. It was proved that the leading sector selected by DFM must be key sector selected by Hirschman-Rasmussen method. Applied DFM to input-output tables of China, Japan and USA and MFA to Japan and USA, the results analysis showed that DFM could overtake the two main shortcomings of minimum flow analysis (MFA), scratch SIS of each economy with its own characteristics, visualize the general evolution rules of the industrial structure with crisscrossed conjunctions among leading sectors.