Screening Proteins that Interact with Rab39A via Yeast Two-hybrid System

目的:应用酵母双杂交方法,寻找可能与rAb39A相互作用的蛋白。方法:采用醋酸锂转化法将诱饵蛋白rAb39A转入AH109酵母菌,WESTErn blOTTIng检测蛋白表达情况,检测诱饵载体有无毒性和自激活能力,筛选出的蛋白通过免疫荧光法进一步验证。结果:获得12个与rAb39A相互作用的候选蛋白,免疫荧光法证明rAb39A与ATrn、TIfA、ITgb1蛋白确实存在互作关系。结论:筛选出的蛋白主要与细胞生长、肿瘤细胞形成有关,为rAb39A功能的研究提供了重要线索。Objective:Using Yeast-two-hybrid method to inquire proteins interacting with Rab39A.Method:The bait plasmid pGBKT7-Rab39A was transfected into AH109 yeast,checking proteins expression,checking the auto-activity and toxicity of recombined plasmid,the interactions were further confirmed with immunofluorescence experiment.Result:12 positive proteins possibly interacting with Rab39A were obtained.The interactions of Rab39A with ATRN,TIFA,ITGB1 were further confirmed by immunofluorescence.Conclusion:The screened proteins have relation with cell growth,cancer cell formation,providing important clues for further investigation of biological function of Rab39A.国家自然科学基金面上项目(“新Rab蛋白对甘露糖-6-磷酸受体及其介导的溶酶体蛋白质运输路径的调控作用及机制研究”;No.30971442、31071176); 福建省自然科学基金项目(“小GTP酶Rab蛋白在人类乳腺癌发生过程中的调控作用”;2010J01234)资

Drag reduction using riblets downstream of a high Reynolds number inclined forward step flow

Micro-riblet is an efficient passive method for controlling turbulent boundary layers, with the potential to reduce frictional drag. In various applications within the transportation industry, flow separation is a prevalent flow phenomenon. However, the precise drag reduction performance of riblets in the presence of flow separation remains unclear. To address this, an inclined forward step model is proposed to investigate the interaction between riblet and upstream flow separation. The large eddy simulation (LES) method is applied to simulate the flow over geometries with different step angles and riblet positions. The results show riblets still reduce wall frictional resistance when subjected to the upstream flow separation. Remarkably, as the angle of the step increases from 0 degrees to 30 degrees, the drag reduction experiences an increment from 9.5% to 12.6%. From a turbulence statistics standpoint, riblets act to suppress the Reynold stress in the near-wall region and dampen ejection motions, thus weakening momentum exchange. Quadrant analysis reveals that with the augmentation of flow separation, the Q2 motion within the flow field intensifies, subsequently enhancing the riblet-induced drag reduction. Moreover, the position of the rib lets has a significant impact on the pressure drag. Riblets close to the point of separation enhance flow separation, altering the surface pressure distribution and thus increasing the resistance. The results reveal that when the riblets are positioned approximately 160 riblet heights away from the step, their effect on the upstream flow separation becomes negligible. The precise performance of riblets under complex flow conditions is important for their practical engineering application

First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring

In a companion paper, we present the first spatially resolved polarized image of Sagittarius A* on event horizon scales, captured using the Event Horizon Telescope, a global very long baseline interferometric array operating at a wavelength of 1.3 mm. Here we interpret this image using both simple analytic models and numerical general relativistic magnetohydrodynamic (GRMHD) simulations. The large spatially resolved linear polarization fraction (24%–28%, peaking at ∼40%) is the most stringent constraint on parameter space, disfavoring models that are too Faraday depolarized. Similar to our studies of M87*, polarimetric constraints reinforce a preference for GRMHD models with dynamically important magnetic fields. Although the spiral morphology of the polarization pattern is known to constrain the spin and inclination angle, the time-variable rotation measure (RM) of Sgr A* (equivalent to ≈46° ± 12° rotation at 228 GHz) limits its present utility as a constraint. If we attribute the RM to internal Faraday rotation, then the motion of accreting material is inferred to be counterclockwise, contrary to inferences based on historical polarized flares, and no model satisfies all polarimetric and total intensity constraints. On the other hand, if we attribute the mean RM to an external Faraday screen, then the motion of accreting material is inferred to be clockwise, and one model passes all applied total intensity and polarimetric constraints: a model with strong magnetic fields, a spin parameter of 0.94, and an inclination of 150°. We discuss how future 345 GHz and dynamical imaging will mitigate our present uncertainties and provide additional constraints on the black hole and its accretion flow

Design of Interface Module for Actuator Based on Profibus-DP

针对大量不具有现场总线接口的执行器很难在网络远程化控制中发挥作用的问题,从改造传统执行器使其具有总线接口功能的工程应用实际出发,采用嵌入式系统的设计方法,以专用接口芯片SPC3为协议转换核心、AD7705和DAC7615为模拟前端,完成了执行器到Profibus-DP总线的接口模块设计,以较低的成本提高了执行器的智能化水平,达到了预期的设计目的

长江流域国土空间开发适宜性综合评价

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