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排序方式: 共有1293条查询结果,搜索用时 46 毫秒
91.
A mammalian genetic system to screen for small molecules capable of disrupting protein-protein interactions 总被引:2,自引:0,他引:2
Zhao HF Kiyota T Chowdhury S Purisima E Banville D Konishi Y Shen SH 《Analytical chemistry》2004,76(10):2922-2927
A mammalian two-hybrid system was developed for high-throughput screening of compounds that disrupt specific protein-protein interactions. The existing mammalian systems are unsatisfactory for drug screening due to nonregulated expression of interacting proteins. To construct a tightly regulated system, the tetracycline repressor was fused with the inhibitory KRAB domain as a suppressor. The binding of the suppressor to the tet operator entirely blocked expression of two interacting proteins. When both the inducer doxycycline and drugs were added to the culture, the reporter gene was either activated by interaction of the paired proteins with ineffective drugs or remained silent due to disruption of the protein interactions by the effective drugs. We demonstrate that interactions of the type I receptor for TGFbeta with FKBP12 and the epidermal growth factor receptor (EGFR) with p85 are effectively disrupted by FK506 and EGFR kinase inhibitor AG1478, respectively. The power of this system for drug screening was further demonstrated by rapid identification of inhibitors from a druglike library for the receptor kinases. 相似文献
92.
One approach to aberration compensation of an imaging system is to introduce a suitable phase mask at the aperture plane of an imaging system. We utilize this principle for the compensation of astigmatism. A suitable polarization mask used on the aperture plane together with a polarizer-retarder combination at the input of the imaging system provides the compensating polarization-induced phase steps at different quadrants of the apertures masked by different polarizers. The aberrant phase can be considerably compensated by the proper choice of a polarization mask and suitable selection of the polarization parameters involved. The results presented here bear out our theoretical expectation. 相似文献
93.
García-Suárez O Pérez-Pérez M Germanà A Esteban I Germanà G 《Microscopy research and technique》2003,62(6):514-523
The thymus undergoes an age-dependent degenerative process which is mainly characterized by a progressive loss of lymphoid tissue. Thymic involution is particularly important in relation to immunosenescence and its various associated diseases; this fact has prompted many studies aimed at understanding the causes and mechanisms of thymic degeneration which may, ultimately, lead to the possibility of manipulating it. In this sense, one of the aspects which has deserved most attention is the thymic microenvironment, and more precisely, the many growth factors to which the cells present in the organ are exposed. Thus, the levels of several of such factors have been reported to undergo age-dependent changes in the thymus, which may point at an influence on the regression of the organ. In this article we consider which growth factors and growth factor receptors occur in the vertebrate thymus. Then, focusing on those whose influences are better documented, i.e., neurotrophins, cytokines and IGFs, we discuss their potential role in the organ and the possibility of their being involved in thymic involution. 相似文献
94.
Manziba Akanda Nishi Chowdhury Farhan Ahmed Md. Samiullah Byeong-Soo Jeong 《Expert systems with applications》2013,40(8):3015-3027
The goal of analyzing a time series database is to find whether and how frequent a periodic pattern is repeated within the series. Periodic pattern mining is the problem that regards temporal regularity. However, most of the existing algorithms have a major limitation in mining interesting patterns of users interest, that is, they can mine patterns of specific length with all the events sequentially one after another in exact positions within this pattern. Though there are certain scenarios where a pattern can be flexible, that is, it may be interesting and can be mined by neglecting any number of unimportant events in between important events with variable length of the pattern. Moreover, existing algorithms can detect only specific type of periodicity in various time series databases and require the interaction from user to determine periodicity. In this paper, we have proposed an algorithm for the periodic pattern mining in time series databases which does not rely on the user for the period value or period type of the pattern and can detect all types of periodic patterns at the same time, indeed these flexibilities are missing in existing algorithms. The proposed algorithm facilitates the user to generate different kinds of patterns by skipping intermediate events in a time series database and find out the periodicity of the patterns within the database. It is an improvement over the generating pattern using suffix tree, because suffix tree based algorithms have weakness in this particular area of pattern generation. Comparing with the existing algorithms, the proposed algorithm improves generating different kinds of interesting patterns and detects whether the generated pattern is periodic or not. We have tested the performance of our algorithm on both synthetic and real life data from different domains and found a large number of interesting event sequences which were missing in existing algorithms and the proposed algorithm was efficient enough in generating and detecting periodicity of flexible patterns on both types of data. 相似文献
95.
96.
Sandip Ghosh Chowdhury Amit Mondal Jen Gubicza Gyrgy Krllics rpd Fodor 《Materials Science and Engineering: A》2008,490(1-2):335-342
The evolution of microstructure and texture in Al6082 precipitation-hardened alloy during equal-channel angular pressing (ECAP) was studied. It was found that although the dislocation density and the subgrain size saturated after 1 pass, the size of grains bounded by high angle boundaries reached its minimum value only after 4 passes. Furthermore, the grain orientation distribution changes between 4 and 8 passes, indicating the development of grain boundary structure even after the saturation of the parameters of the microstructure. As a result of this evolution, the initial texture of the commercial alloy was diminished after 8 passes and the grain orientation distribution became to be close to random case. 相似文献
97.
98.
Giakos G.C. Chowdhury S. Shah N. Mehta K. Sumrain S. Passerini A. Patnekar N. Evans E.A. Fraiwan L. Ugweje O.C. Nemer R. 《IEEE transactions on instrumentation and measurement》2002,51(5):949-954
In this study, experimental results on the signal quality of a multimedia imaging detector, operating on gaseous solid state ionization principles, with specific emphasis on single X-ray exposure dual-energy radiography, are presented. The results of this study indicate that the multimedia detector technology exhibits excellent signal characteristics suitable for a large number of imaging applications. 相似文献
99.
In this work, we deal with the 1D compressible fluid coupled with elastic solid in an Eulerian-Lagrangian system. To facilitate
the analysis, the Naviers equation for elastic solid is cast into a 2×2 system similar to the Euler equation but in Lagrangian
coordinate. The modified Ghost Fluid Method is employed to treat the fluid-elastic solid coupling, where an Eulerian-Lagrangian
Riemann problem is defined and a nonlinear characteristic from the fluid and a Riemann invariant from the solid are used to
predict and define the ghost fluid states. Theoretical analysis shows that the present approach is accurate in the sense of
approximating the solution of the Riemann problem at the interface. Numerical validation of this approach is also accomplished
by extensive comparison to 1D problems (both water-solid and gas-solid) with their respective analytical solutions.
T.G. Liu’s current address: Department of Mathematics, Beijing University of Aeronautics and Astronautics, Beijing 100083.
email: liutg@buaa.edu.cn. 相似文献
100.
Pranesh Chowdhury Abhijit Mukherjee B. Singha Palash Mondal Kousik Roy 《Journal of Polymer Research》2010,17(6):853-860
The effects of different parameters such as time, concentration, pH and temperature, on metal ion retention properties of
the polymer have been investigated. Metal ion adsorption kinetics, isotherms and thermodynamics have been studied. A plausible
mechanism for mercury ion retention has been suggested. Mercuric ion has been isolated quantitatively from various synthetic
mixture containing metal ions (Ni2+, Cd2+, Pb2+ and Zn2+). 相似文献