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流式细胞分选装置的研制与发展 总被引:1,自引:0,他引:1
在自己研制的流式细胞仪上开发出了流式细胞分选装置。分选的方法是给含有目标细胞的液滴充电,使之在静电场中偏转。该装置有以下优点:由于全部电路由同一方波模式振动源驱动,液滴形成过程和充电脉冲产生过程完全同步;独特考虑的分选逻辑电路能识别细胞类型,自动调整充电脉冲宽度,能在保证高分选纯度的前提下获得更高的分选收获率和分选速度;在不应期里出现另一细胞时能予以处理。为了更好地使用分选装置,本文还从仪器角度和样品角度分析讨论了影响分选指标的因素。 相似文献
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合成生物电路在生物传感及生物计算方面成为了广泛应用的工具。工程化生物电路系统具有良好的灵活性,同时也具备模块化的特征。在本文中,研究了基于单链DNA开关调控的多功能生物电路的构建方法。通过将计算机辅助设计的单链DNA开关作为核心控制元件,并利用长度为20 bp的toehold区域来激活单链DNA开关,驱动了简单的单向式、循环式以及级联的多层次的生物电路系统。在级联式电路系统中,通过调整单链DNA开关的结构,使信噪比从2.996变成5.274。同时,单链DNA开关作为长单链DNA(784 bp)的一部分,在无细胞蛋白质系统中实现了基因表达调控。因此,本文研究的工程化方法为今后复杂的人工生物电路的构建提供了坚实的技术基础。 相似文献
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番茄线粒体和内质网小分子热激蛋白基因的分子克隆 总被引:10,自引:0,他引:10
以热激处理的番茄(Lycopersicon esculentum Mill.)花为实验材料,构建了cDNA库,运用RT-PCR方法克隆番茄粒体和内质网小分子热激蛋白cDNA,利用这两个保守区片段为探针,筛选cDNA库,获得线粒体和内质网小分子热激蛋白全序列cDNA。;通过分析线粒体和内质网小分子热激蛋白基因对温度的反应,发现小分子热激蛋白基因在番茄花中的热激应答温度低于它们在叶片中的热激应答温度,并且番茄叶片中的线粒体小分子热激蛋白基因还具有低温应答特性。对线粒体和内质网小分子热激蛋白基因的分子结构特点,小分子热激蛋白基因在番茄花中的特别热激应答温度的调控机理以及线粒体小分子热激蛋白的基因在中片中的低温度应答成因进行了讨论。 相似文献
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Ibp A是小分子热激蛋白家族成员。Ibp A和Ibp B协同作用,与其他伴侣蛋白一起在热激反应中保护底物蛋白,消除凝集,产生重折叠,回复活性。概述了Ibp A在热激反应中的作用、ibp A基因表达的调控和Ibp A分子结构对其功能的影响。 相似文献
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心电标测是心脏电生理机理研究的主要方法,也是临床精密诊断和对心律失常病灶进行精确定位的重要手段,特别适用于房颤等复杂心律失常电生理机制的研究.该文主要介绍了心外膜电位标测系统中的前置放大模块的设计,并根据实际需要,增加了右腿驱动电路.通过人体与动物实验检测,应用右腿驱动电路后均能得到清楚的心电波形. 相似文献
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雄蝇追逐行为的分析 总被引:2,自引:1,他引:1
本文报告了在自由飞行条件下雄蝇追逐的行为实验及其分析的初步结果.其结果如下:1.追逐雄蝇水平方向偏转的角速度dF_1线性地依赖于目标蝇水平方位误差角T_1的大小.当目标在前视场中,即空间误差角|G|<π/4时,线性回归直线的斜率约为37**;而当空间误差角|G|>π/4时,线性回归直线的斜率约为6.7.2.追逐雄蝇俯仰方向偏转角速度dF_2在(-(π/2),π/2)的范围内线性依赖于俯仰误差角T_2的大小,其回归直线的斜率约为14.3.雄蝇追逐行为中,水平方位误差角频数分布的直方图呈现为峰值在零点的对称型分布;而俯仰误差角T_2频数分布的直方图是非对称型的,即仰角出现的频数大大超过俯角出现的频数.4.雄蝇主要利用了两蝇间距离变化dD的信息以及目标误差角来控制向前飞行的速度V.当误差角小时(即目标在前视场中),dD一般为负值,说明两蝇间的距离减小,而雄蝇追逐飞行的加速度A却与dD呈现正的线性关系.当误差角大时(即目标位于后视场中),dD一般为正值,说明两蝇间的距离增加. 相似文献
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Direct‐Current Triboelectric Nanogenerator Realized by Air Breakdown Induced Ionized Air Channel
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Jianjun Luo Liang Xu Wei Tang Tao Jiang Feng Ru Fan Yaokun Pang Libo Chen Yan Zhang Zhong Lin Wang 《Liver Transplantation》2018,8(27)
The air breakdown phenomenon is generally considered as a negative effect in previous research on triboelectric nanogenerators (TENGs), which is always accompanied by air ionization. Here, by utilizing the air breakdown induced ionized air channel, a direct‐current triboelectric nanogenerator (DC‐TENG) is designed for harvesting contact‐separation mechanical energy. During working process, the charges first transfer from bottom to top electrodes through an external circuit in contact state, then flow back via the ionized air channel created by air breakdown in the separation process. So a unidirectional flow of electrical charges can be observed in the external circuit. With repeating contact‐separation cycles, continuous pulsed DC output through the external circuit can be realized. This working mechanism was verified by real‐time electrode potential monitoring, photocurrent signal detection, and controllable discharging observation. The DC‐TENG can be used for directly and continuously charging an energy storage unit and/or driving electronic devices without using a bridge rectifier. Owing to its simplicity in structure, the mechanism is further applied to fabricate the first flexible DC‐TENG. This research provides a significant fundamental study for DC‐TENG technology and may expand its application in flexible electronics and flexible self‐charging power systems. 相似文献
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Vosshall LB 《Neuron》2008,59(5):685-689
Sexual courtship is a highly ritualized behavior in many animals. Recent work in the vinegar fly, Drosophila melanogaster, has illuminated how the pheromone cis-vaccenyl acetate modulates sexual behavior in the fly. Chemosensory receptors and a sexually dimorphic circuit activated by this pheromone have been identified. This minireview highlights recent advances in the field of fly courtship. 相似文献
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A low-voltage droplet charging circuit with simulative cell-sorting function for flow cytometer-cell sorter 总被引:1,自引:0,他引:1
BACKGROUND: Flow cytometer cell sorters have become important tools in many biological laboratories. Commercial electrically-deflected cell sorters that deflect wanted cells in electrically charged droplets need high-voltage amplifiers which are expensive and difficult to obtain. Effort was made to build an alternative droplet charging circuit with low-voltage amplifiers that are much easier to get and have more reasonable price. METHODS: A low-voltage charging circuit was designed. Every time a cell was to be separated, a pair of complementary charging pulses were produced: one was positive and the other was negative with equal amplitude. These were enlarged by two low-voltage charging amplifiers to drive two charging electrodes respectively. RESULTS: Due to the effect of addition, the voltage between the two electrodes was double as high as the output of either amplifier. The result of test experiment proved that the cell sorter with low-voltage amplifiers, which was cheaper and easier to obtain, could separate cells as efficiently as the instrument with high-voltage ones that were more expensive and more difficult to make. In addition, a simulative cell-sorting function was provided. CONCLUSIONS: This low-voltage, easily-built and low-price charging circuit for flow cytometer cell sorter is a good alternative to the commonly used high-voltage one, especially to researcher who hopes to build his own personal instrument. 相似文献
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Equivalent Circuit of Frog Atrial Tissue as Determined by Voltage Clamp-Unclamp Experiments 总被引:6,自引:3,他引:3
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The equivalent circuit that has been used in the analysis of nerve voltage-clamp data is that of the membrane capacity in parallel with the membrane resistance. Voltage-clamp experiments on frog atrial tissue indicate that this circuit will not suffice for this cardiac tissue. The change in membrane current associated with a step change in membrane potential does not show a rapid spike of capacitive current as would be expected for the simple parallel resistance-capacitance network. Rather, there is a step change in current followed by an exponential decay in current with a time constant of about 1 msec. This relatively slow capacitive charging current suggests that there is a resistance in series with the membrane capacity. A possible equivalent circuit is that of a series resistance external to the parallel resistance-capacitance network of the cell membranes. Another possible circuit assumes that the series resistance is an integral part of the cell membrane. The data presented in this paper demonstrate that the equivalent circuit of a bundle of frog atrial muscle is that of an external resistance in series with the cell membranes. 相似文献
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Nonassociative learning is an important property of neural organization in both vertebrate and invertebrate species. In this paper we propose a neural model for nonassociative learning in a well studied prototypical sensory-motor scheme: the landing reaction of flies. The general structure of the model consists of sensory processing stages, a sensory-motor gate network, and motor control circuits. The paper concentrates on the sensory-motor gate network which has an agonist-antagonist structure. Sensory inputs to this circuit are transduced by chemical messenger systems whose dynamics include depletion and replenishment terms. The resulting circuit is a gated dipole anatomy and we show that it gives a good account of nonassociative learning in the landing reaction of the fly.Supported by a grant from the National Institute of Mental Health 相似文献
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The olfactory circuit of the fruit fly Drosophila melanogaster has emerged in recent years as an excellent paradigm for studying the principles and mechanisms of information processing in neuronal circuits. We discuss here the organizational principles of the olfactory circuit that make it an attractive model for experimental manipulations, the lessons that have been learned, and future challenges. 相似文献
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雄蝇追逐飞行的加速度分析 总被引:2,自引:1,他引:1
本文报导了采用高速摄影技术,通过分析雄蝇追逐飞行的加速度对视觉制导问题所进行的研究.我们的结果如下:1.目标蝇的角位置与追逐蝇相应的角加速度分量之间,在追逐蝇的全视场中呈现非线性的关系.追逐蝇的水平角加速度分量与水平误差角在前视场中有较好的线性关系.追逐蝇的俯仰角加速度分量与俯仰误差角之间,当目标蝇位于前上半视场中时,呈现较好的线性关系.2.目标蝇相对追逐蝇的角运动对追逐蝇的相应角加速度分量也有影响,这种影响与目标蝇位置的关系不大.3.对于目标蝇在前后视场中的两种情况,两蝇间的距离对追逐蝇加速度大小影响的规律是不同的:当目标蝇在前视场中时,只经过较短的延迟时间两蝇间的距离与追逐蝇加速度大小出现了正的相关峰,而后视场中的情况不然,它需要较长的延迟时间.两蝇间距离的变化对追逐蝇加速度大小的影响也有类似的现象.4.在追逐过程中雄蝇利用背前区的小眼来追逐带头的目标雌蝇,而组织学研究在雄蝇背前区的小眼中发现了性特化的中心小网膜细胞,与行为研究的结果相呼应.5.文中最后对蝇视觉神经系统中如何获取目标绳的位置和运动参数的问题进行了讨论. 相似文献