排序方式: 共有21条查询结果,搜索用时 15 毫秒
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DNA结合蛋白结构域的研究进展* 总被引:2,自引:0,他引:2
本文综述了3种DNA结合蛋白结构域-螺旋一转折一螺旋、亮氨酸拉链、锌指近年来的研究进展。参考文献65篇。 相似文献
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含亮氨酸拉链型脂肽的温敏性脂质体被认为是抗癌药物的优良载体。亮氨酸拉链型脂肽的主要氨基酸残基序列为[VAQLEVK-VAQLESK-VSKLESK-VSSLESK],嵌入脂质体后可以有效改善脂质体的温敏性。本文首先采用隐式溶剂副本交换分子动力学方法,对N端修饰的亮氨酸拉链单链的折叠状态进行了模拟,得到了亮氨酸拉链单链的转变温度。并对包含该种新型亮氨酸拉链型脂肽的DPPC脂质体进行常规分子动力学模拟,研究了2种不同头基的亮氨酸拉链型脂肽(ALA,C3CO)二聚体嵌入后DPPC脂质体的相转变温度变化,证明了亮氨酸拉链型脂肽对于该脂质体温敏性的控制作用。利用这一规律,可以对亮氨酸拉链型脂肽进行优化改良,得到效果更佳的温敏脂质体,对于抗癌药物载体的开发有着重要的意义。 相似文献
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亮氨酸拉链型脂肽是由两条肽链以螺旋结构依靠疏水作用并列结合形成的二聚体,当温度升至其相变温度时,其螺旋结构解旋继而变为无序链状结构。利用该类脂肽的温敏性能,本文设计、合成得到一组具有温敏性的拉链型脂肽,将其与磷脂混合制备温敏性脂质体。用圆二色谱测定磷脂双分子层上脂肽的二级结构,动态光散射测定脂肽-脂质体的粒径及电位;荧光偏振法测定脂质体膜的流动性;采用紫外分光光度计考察阿霉素(DOX)在37.0、45.0°C下的释放行为。结果表明,含有脂肽的脂质体具备较好的温敏性,胆固醇含量、脂质体膜的流动性,对脂肽的温控开关效应有一定的影响。脂肽-脂质体作为一种新型的温敏性药物载体展现了其较好的应用前景。 相似文献
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采用二维滞止流模型,讨论了工业洁净室内不同送风速度下,气溶胶粒子分别受重力和电场力作用及二者联合作用时在工作台表面或晶片上的沉积特征。通过与相关文献提供的实验数据的对比,确认了这种预报超细粒子沉积行为的方法。 相似文献
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Theoretical analysis is made on the temperature field at the time of pulse current discharge in a metal structure with an elliptical embedding crack. In finding the temperature field, analogy between the current flow through an elliptical embedding crack and the fluid flow through a barrier is made based on the similarity principle. Boundary conditions derived from this theory are introduced so that the distribution of current density and the temperature field expressions can be obtained. The study provides a theoretic basis to the applications of stopping spatial crack with electromagnetic heating. 相似文献
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Zhang Yin Murphy Kevin D. 《Acta Mechanica Solida Sinica》2007,20(3):236-246
In the present paper,a simple mechanical model is developed to predict the dynamic response of a cracked structure subjected to periodic excitation,which has been used to identify the physical mechanisms in leading the growth or arrest of cracking.The structure under consideration consists of a beam with a crack along the axis,and thus,the crack may open in Mode I and in the axial direction propagate when the beam vibrates.In this paper,the system is modeled as a cantilever beam lying on a partial elastic foundation,where the portion of the beam on the foundation represents the intact portion of the beam.Modal analysis is employed to obtain a closed form solution for the structural response.Crack propagation is studied by allowing the elastic foundation to shorten(mimicking crack growth)if a displacement criterion,based on the material toughness,is met.As the crack propagates,the structural model is updated using the new foundation length and the response continues.From this work,two mechanisms for crack arrest are identified.It is also shown that the crack propagation is strongly influenced by the transient response of the structure. 相似文献
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本文建立了预混滞止火焰燃烧实验装置,采用激光多普勒技术对湍流冷态流场进行了诊断。对测量的速度信息进行了分析和处理,得到了该测点的欧拉时间关联函数和积分时间尺度,并通过傅立叶转换得出湍流冷态流场的湍谱特性。该实验结果和数据处理方法为将来的热态实验提供了基础数据和技术支持。 相似文献
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