Studies on biomechanics of skeletal muscle based on the working mechanism of myosin motors: An overview

Skeletal muscle is the source of human body motion.Many scholars have been studying in this field to reveal its contraction mechanism,and relevant achievements have been awarded the Nobel Prize.This paper reviewed the current researches on biomechanics of skeletal muscle,and concluded two strategies(top-down and bottom-up methods) for the biomechanical research of skeletal muscle.Moreover,this paper generalized two major aspects of muscle research:(1) the multi-force coupling mechanism and the collective operation mechanism of molecular motors;(2) the bioelectrochemical driving and control principium of muscle contraction.We discussed the solution for experimental verification and induced a novel idea to study the biomechanics of skeletal muscle based on the microscopic working mechanism of molecular motor,which is the origin of muscle contraction.Finally we analyzed the disadvantages in existent researches and explored future directions that need further studies.     

Theoretical study on stereodynamics of H + NeH+ (v = 0, j = 0) → H2 + + Ne reaction

Stereodynamics of reaction H + NeH+(v = 0,j = 0) → H2+ + Ne is investigated by quasi-classical trajectory method using a new potential energy surface constructed by Lv et al.The distributions of P(r),P(r) and PDDCSs are calculated at four different collision energies.The rotational polarization of product H2+ presents different characters at different collision energies.The product rotational angular momentum vector j’ is not only aligned,but also oriented along the direction perpendicular to the scattering plane.With the increase of collision energy,the rotation of product molecule has a preference of changing from the "in-plane" mechanism to the "out-of-plane" mechanism.Although the title reaction is mainly dominated by the direct reaction mechanism,the indirect mechanism plays a role when the collision energies are low.     

高职院校学生作弊成因分析及对策研究

针对高等职业院校生源紧张、学生质量下降的实际情况,分析在当前形势下,高等职业院校大学生考试作弊手段以及引发大学生作弊的原因,并试图找出杜绝高职院校大学生作弊行为的举措。     

干旱胁迫下铁皮石斛愈伤组织生理特性研究

以铁皮石斛愈伤组织为材料,采用PEG-6000模拟干旱胁迫处理铁皮石斛愈伤组织,检测愈伤组织可溶性蛋白含量及SOD、POD和APX活性的变化动态。结果表明,不同浓度PEG胁迫下,铁皮石斛愈伤组织可溶性蛋白均高于对照;各浓度PEG胁迫1d后,SOD活性均高于对照,当PEG浓度为30%时,胁迫2d、3d后却低于对照;POD活性随着PEG浓度的增强先上升后下降,在25%PEG胁迫下达到峰值;当PEG浓度为30%时,APX活性随着时间的延长而降低,当PEG浓度低于30%时,APX活性呈上升趋势。铁皮石斛愈伤组织可通过可溶性蛋白含量的增加和保护酶的变化来适应一定程度的干旱胁迫。     

Burgers方程不变群的生成元和对称约化

以Burgers方程为对象,研究了方程的不变群的生成元、对称约化问题.利用李群对称求出方程的解,并给出方程的生成元求法,及对称解,最后通过数值模拟验证了其有效性.     

基于应用型人才培养模式的生物技术专业课程体系的构建

课程体系改革是人才培养模式改革创新的一项重要内容,有利于当代大学生合理素质结构、知识结构和能力结构的形成.为解决生物技术专业课程设置中存在的一些问题,提出了一种面向实际、细化专业方向、集中体现地方院校应用型人才培养特色的生物技术专业课程体系.     

带可变核的分数次积分交换子的有界性

研究由带变量核的分数次积分算子TΩ,α和Lipβ（Rn）（0〈β≤1）函数生成的交换子[b,TΩ,α],证明了当核函数Ω∈L∞×Lr（Sn-1）（r≥1）时,[b,TΩ,α]从Herz型Hardy空间H.Kηq,p1（Rn）到Herz型空间Kηq,p2（Rn）的有界性.     

局放放电联合检测中光-电信号与放电量关联关系的修正

基于实验室搭建的局部放电光-电信号联合检测平台,进行了4种典型缺陷下局放模拟检测实验,获取了局放的光信号和电信号。本文分析了两类局部放电信号与GIS模拟腔体内部的视在放电量之间的关系,同时,根据现场试验中,真实存在的一些影响因素对结果进行了修正,分别从不同气压下超高频（UHF）检测信号与视在放电量之间的关系和不同尺寸绝缘缺陷下光测法信号与视在放电量之间的关系两方面进行了修正。获取了气压对UHF信号影响的修正公式,取模拟腔体内气压3bar时,对修正值与实际测量值进行比较,得到除自由金属微粒缺陷（相对误差为14.4%）外,其它缺陷的相对误差均小于5%;获取了不同缺陷尺寸下对光测法信号影响的修正公式,选取各类缺陷的最小尺寸,对修正值与实测值进行比较发现,除自由金属微粒缺陷外,其他缺陷的相对误差均小于10%,验证了修正结果的可靠性。     

基于全息扫描的大型复杂钢结构变形监测与受力评估新技术

以重庆来福士高空连廊结构为项目依托,阐述了大型复杂钢结构变形监测的新方法和具体技术路线。针对变形监测中点云数据难以拼接的问题,通过空间特征点实现坐标系配准;针对变形监测点选取困难、数量多、工作量大的问题,提出一种基于算法提取结构的挠度变形曲线的方法,实现无监测点的变形监测;同时将有限元仿真模拟与三维激光扫描技术的变形监测相融合,根据三维扫描变形监测结果反向修正有限元计算,通过应力变化评估结构受力状态。结果表明:该方法有效解决了变形监测中的难题,保证了工作的效率和有限元计算的准确性,对于结构的健康监测具有重要意义。     

NMDA receptors mediate calcium accumulation in myelin during chemical ischaemia

Central nervous system myelin is a specialized structure produced by oligodendrocytes that ensheaths axons, allowing rapid and efficient saltatory conduction of action potentials. Many disorders promote damage to and eventual loss of the myelin sheath, which often results in significant neurological morbidity. However, little is known about the fundamental mechanisms that initiate myelin damage, with the assumption being that its fate follows that of the parent oligodendrocyte. Here we show that NMDA (N-methyl-d-aspartate) glutamate receptors mediate Ca2+ accumulation in central myelin in response to chemical ischaemia in vitro. Using two-photon microscopy, we imaged fluorescence of the Ca2+ indicator X-rhod-1 loaded into oligodendrocytes and the cytoplasmic compartment of the myelin sheath in adult rat optic nerves. The AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)/kainate receptor antagonist NBQX completely blocked the ischaemic Ca2+ increase in oligodendroglial cell bodies, but only modestly reduced the Ca2+ increase in myelin. In contrast, the Ca2+ increase in myelin was abolished by broad-spectrum NMDA receptor antagonists (MK-801, 7-chlorokynurenic acid, d-AP5), but not by more selective blockers of NR2A and NR2B subunit-containing receptors (NVP-AAM077 and ifenprodil). In vitro ischaemia causes ultrastructural damage to both axon cylinders and myelin. NMDA receptor antagonism greatly reduced the damage to myelin. NR1, NR2 and NR3 subunits were detected in myelin by immunohistochemistry and immunoprecipitation, indicating that all necessary subunits are present for the formation of functional NMDA receptors. Our data show that the mature myelin sheath can respond independently to injurious stimuli. Given that axons are known to release glutamate, our finding that the Ca2+ increase was mediated in large part by activation of myelinic NMDA receptors suggests a new mechanism of axo-myelinic signalling. Such a mechanism may represent a potentially important therapeutic target in disorders in which demyelination is a prominent feature, such as multiple sclerosis, neurotrauma, infections (for example, HIV encephalomyelopathy) and aspects of ischaemic brain injury.