Mechanosensitivity of mammalian auditory hair cells in vitro

Intracellular responses recorded in vitro from the cochleas of anaesthetized mammals have shown that the mechanoreceptive inner and outer hair cells are sharply tuned, accounting for many of the properties of the afferent fibres in the auditory nerve. However, in vivo it has not been possible to measure directly the excitatory mechanical input to these cells (the displacement of their mechanosensitive stereocilia) and thus to determine the relationship between the receptor potentials and displacement of their stereocilia. As a means of circumventing this technical difficulty, we have developed an organ culture of the mouse cochlea and here we describe the receptor potentials generated by the hair cells in response to direct displacement of their stereocilia.     

Force generation by mammalian hair bundles supports a role in cochlear amplification

It is generally accepted that the acute sensitivity and frequency discrimination of mammalian hearing requires active mechanical amplification of the sound stimulus within the cochlea. The prevailing hypothesis is that this amplification stems from somatic electromotility of the outer hair cells attributable to the motor protein prestin. Thus outer hair cells contract and elongate in synchrony with the sound-evoked receptor potential. But problems arise with this mechanism at high frequencies, where the periodic component of the receptor potential will be attenuated by the membrane time constant. On the basis of work in non-mammalian vertebrates, force generation by the hair bundles has been proposed as an alternative means of boosting the mechanical stimulus. Here we show that hair bundles of mammalian outer hair cells can also produce force on a submillisecond timescale linked to adaptation of the mechanotransducer channels. Because the bundle motor may ultimately be limited by the deactivation rate of the channels, it could theoretically operate at high frequencies. Our results show the existence of another force generator in outer hair cells that may participate in cochlear amplification.     

溶剂热法制备ZnS纳米线束

采用单一前驱体溶剂热法,在聚乙烯吡咯烷酮(PVP)作表面活性剂条件下,成功合成了ZnS纳米线束.利用X射线衍射(XRD)、透射电子显微镜(TEM)、傅里叶红外变换吸收光谱及光致发光测试对样品的结构、形貌及物理性能进行了分析与表征.结果表明,所得产物为纯的六面体纤维锌矿ZnS纳米线束,直径在20~30 nm,长度为1.5~2.0μm,并对ZnS纳米线束的形成机理进行了探讨.     

根瓣丛的普查

对于给定的棱数，得到不同构的可定向与不可定向根瓣丛的数目，同时，独立地得到给定棱数的全体根瓣丛的数目，所有这些数均表示为棱数的单项函数，即无和表示。     

马尔可夫更新方程及其应用

研究了更新理论的推导过程,在特殊条件下用L变化得到了更新方程的解并举例说明了它在可靠性理论中的应用.     

Myocyte renewal and ventricular remodelling.

Remaining young at heart is a desirable but elusive goal. Unbeknown to us, however, myocyte regeneration may accomplish just that. Continuous cell renewal in the adult myocardium was thought to be impossible, but multipotent cardiac stem cells may be able to renew the myocardium and, under certain circumstances, can be coaxed to repair the broken heart after infarction.     

模丛之间的浸入关系

 利用张量和模代数知识,构造出了自由丛的浸入子丛和任一模丛的浸入子自由丛.得到一般模丛都能够成为一个自由丛的浸入子丛;同时任一模丛也能够有一自由丛(或投射丛)是它的浸入子丛;还给出了投射丛转化为自由丛的条件.     

汽车不均匀线束串扰特性预测的改进方法

针对线束的不均匀性及线束中导线间距的随机性,提出了一种采用统计学理论来预测不均匀线束串扰的方法。在弱耦合和电小尺寸的假设条件下,基于集总电路近似模型运用统计方法推导出了串扰电压比的期望值和方差,预测了最坏情况下的串扰。与273RDSI模拟仿真对比,验证了方法的合理性和可行性。最后分析了不同的导线数目和线束距地面高度的情况,结果表明：串扰的期望值和方差都会随导线数目的增加而降低;增大线束距地高度,期望值变大,而方差的变化不是很明显,说明方差对线束距地高度不是很敏感;随着导线数目的增加,期望对高度的变化更加敏感。     

兔毛织物防掉毛的研究

介绍了一种新型的兔毛织物防掉毛方法.阐述了防掉毛机理并分析了影响防掉毛效果的主要因素.     

关于模糊更新过程的交错更新定理

介绍了一种新的交错更新过程———模糊随机交错更新过程,给出了关于模糊随机事件在"系统在t时刻开着"的极限分布定理.     

课程改革与数学教师的观念更新

数学教师现有的数学观、课程观和教学观与数学课程改革对教师各种观念的要求之间存在着明显的差距,这种差距成了数学课程改革的阻力之一．为使数学课程改革能够顺利进行,首先应该努力促使数学教师确立正确的数学观、课程观和教学观。     

企业设备更新决策的科学评价

随着科学技术的进步,国有大型企业设备向着自动化、巨型化发展,设备本身的成本不断提高,设备更新的决策越来越难以决定。如果把模糊技术引入设备更新的辅助决策过程,运用计算机加以实现,这样就可以为企业管理者提供科学依据,使企业管理者合理运用资金,对于企业的运营一定会收到良好的效果。     

城市更新与城市个性化发展

随着城市更新改造的不断深入以及全球化、信息化的影响,现代城市面貌日趋雷同。在城市更新改造的同时,保护和发展城市个性已成为当务之急,我们应让城市焕发出多姿多彩的个性。     

银川市旧城改造与动态管理初探

分析了银川市旧城改造和动态管理的特点及面临的问题，提出在观念的转变和动态的思考中经营城市是城市改造和管理的长远出路．     

知识经济与会计观念更新

本文介绍了知识经济的内涵及基本特征,指出了在知识经济出现的新经济环境下,更新会计观念、增强会计创新意识的若干问题.     

固定资产更新改造方法的数学分析

鉴于企业固定资产更新改造方法的选择不限于一种，为此从价值计量出发，阐述固定资产更新改造的数学机理，给出固定资产效用下降的年数总和折旧法，偿债基金折旧法，年金折旧法和余额递减折旧法，并分析了固定资产效用函数的性质，提出采用回归分析方法来确定固定资产效用函数。     

Tissue repair and stem cell renewal in carcinogenesis

Cancer is increasingly being viewed as a stem cell disease, both in its propagation by a minority of cells with stem-cell-like properties and in its possible derivation from normal tissue stem cells. But stem cell activity is tightly controlled, raising the question of how normal regulation might be subverted in carcinogenesis. The long-known association between cancer and chronic tissue injury, and the more recently appreciated roles of Hedgehog and Wnt signalling pathways in tissue regeneration, stem cell renewal and cancer growth together suggest that carcinogenesis proceeds by misappropriating homeostatic mechanisms that govern tissue repair and stem cell self-renewal.