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排序方式: 共有235条查询结果,搜索用时 15 毫秒
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The response to a strong monochromatic electromagnetic field is investigated for a system with two energy bands. Modified Maxwell-Bloch equations are derived using a Master-equation approach in the rotating frame. Our results imply the vanishing of the stationary polarization in the rotating frame and are equivalent to the replacement of the equilibrium population in the ordinary linear response with the actual population determined by the strong excitation. 相似文献
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Dalu Chang Eric Lindberg Suihan Feng Simona Angerani Howard Riezman Nicolas Winssinger 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16179-16183
Bioluminescence resonance energy transfer (BRET) has been widely used for studying dynamic processes in biological systems such as protein–protein interactions and other signaling events. Aside from acting as a reporter, BRET can also turn on functions in living systems. Herein, we report the application of BRET to performing a biorthogonal reaction in living cells; namely, releasing functional molecules through energy transfer to a coumarin molecule, a process termed bioluminolysis. An efficient BRET from Nanoluc‐Halotag chimera protein (H‐Luc) to a coumarin substrate yields the excited state of coumarin, which in turn triggers hydrolysis to uncage a target molecule. Compared to the conventional methods, this novel uncaging system requires no external light source and shows fast kinetics (t1/2<2 min). We applied this BRET uncaging system to release a potent kinase inhibitor, ibrutinib, in living cells, highlighting its broad utility in controlling the supply of bioactive small molecules in vivo. 相似文献
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An electrostatic switching procedure is introduced that enables the systematic generation of high-quality ice configurations at various temperatures. Proton disordered ice Ih configurations were generated for the TIP4P water model at temperatures from 50 to 240 K, for the SPC/Fw water model from 100 to 240 K, and for the DC97 water model at 240 K. The resulting configurations were found to properly sample the canonical ensemble. The dielectric constant of ice Ih was determined from the net dipole fluctuation of the ice configurations. The calculated dielectric constant compares favorably with the study by Rick and Haymet [J. Chem. Phys. 2003, 118, 9291]. However, our method gives smaller error bars, especially at lower temperatures. At temperatures above 200 K, a type of hydrogen-bond defect is identified that cannot be categorized as a D or L type defect. 相似文献
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Strategies for monitoring the emerging polar organic contaminants in water with emphasis on integrative passive sampling 总被引:2,自引:0,他引:2
Although polar organic contaminants (POCs) such as pharmaceuticals are considered as some of today's most emerging contaminants few of them are regulated or included in on-going monitoring programs. However, the growing concern among the public and researchers together with the new legislature within the European Union, the registration, evaluation and authorisation of chemicals (REACH) system will increase the future need of simple, low cost strategies for monitoring and risk assessment of POCs in aquatic environments. In this article, we overview the advantages and shortcomings of traditional and novel sampling techniques available for monitoring the emerging POCs in water. The benefits and drawbacks of using active and biological sampling were discussed and the principles of organic passive samplers (PS) presented. A detailed overview of type of polar organic PS available, and their classes of target compounds and field of applications were given, and the considerations involved in using them such as environmental effects and quality control were discussed. The usefulness of biological sampling of POCs in water was found to be limited. Polar organic PS was considered to be the only available, but nevertheless, an efficient alternative to active water sampling due to its simplicity, low cost, no need of power supply or maintenance, and the ability of collecting time-integrative samples with one sample collection. However, the polar organic PS need to be further developed before they can be used as standard in water quality monitoring programs. 相似文献
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Daniel Lindberg Rainer Backman Patrice Chartrand 《The Journal of chemical thermodynamics》2006,38(12):1568-1583
A complete, critical evaluation of all phase diagram and thermodynamic data was performed for all phases of the (Na2SO4 + K2SO4 + Na2S2O7 + K2S2O7) system and optimized model parameters were obtained. The Modified Quasichemical Model in the Quadruplet Approximation was used for modelling the liquid phase. The model evaluates first- and second-nearest-neighbour short-range ordering, where the cations (Na+ and K+) are assumed to mix on a cationic sublattice, while anions were assumed to mix on an anionic sublattice. The Compound Energy Formalism was used for modelling the solid solutions of (Na,K)2SO4 and (Na,K)2S2O7. The models can be used to predict the thermodynamic properties and phase equilibria in multicomponent heterogeneous systems. The experimental data from the literature were reproduced within experimental error limits. 相似文献
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Xu Zhang William D. Armstrong William R. Lindberg Jonathan W. Naughton 《Experiments in fluids》2012,53(4):1107-1121
Experimental measurements are used to validate a numerical model of a dynamic resonant wall shear stress sensor. The numerical model consists of an unsteady two-dimensional boundary-layer model for the flow and a simple mechanical model for the sensor itself. The sensor’s sensitivity to wall shear stress is experimentally determined in a flat-plate boundary layer, and the results agree closely with those from the numerical simulations. Using the validated model, it is determined that the energy lost in each sensor oscillation due to the interaction between the sensor and fluid increases with increasing mean wall shear stress. 相似文献
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Diana Lindberg Kenneth Aase Kristoffersen Sileshi Gizachew Wubshet Linn Maria Gundersen Hunnes Marte Dalsnes Katinka Riiser Dankel Vibeke Hst Nils Kristian Afseth 《Molecules (Basel, Switzerland)》2021,26(17)
A study of the effects of single and combined protease hydrolysis on myofibrillar versus collagenous proteins of poultry by-products has been conducted. The aim was to contribute with knowledge for increased value creation of all constituents of these complex by-products. A rational approach was implemented for selecting proteases exhibiting the most different activity towards the major protein-rich constituents of mechanically deboned chicken residue (MDCR). An initial activity screening of 18 proteases on chicken meat, turkey tendons and MDCR was conducted. Based on weight yield, size exclusion chromatography (SEC) and SDS-PAGE, stem Bromelain and Endocut-02 were selected. Studies on hydrolysis of four different poultry by-products at 40 °C, evaluated by protein yield, SEC, and SDS-PAGE, indicate that the proteases’ selectivity difference can be utilized in tailor-making hydrolysates, enriched in either meat- and collagen-derived peptides or gelatin. Three modes of stem Bromelain and Endocut-02 combinations during hydrolysis of MDCR were performed and compared with single protease hydrolysis. All modes of the protease combinations resulted in a similar approximately 15% increase in product yield, with products exhibiting similar SEC and SDS-PAGE profiles. This shows that irrespective of the modes of combination, the use of more than one enzyme in hydrolysis of collagen-rich material can provide means to increase the total protein yield and ultimately contribute to increased value creation of poultry by-products. 相似文献