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排序方式: 共有1054条查询结果,搜索用时 46 毫秒
61.
Protein sizing on a microchip 总被引:6,自引:0,他引:6
We have developed a microfabricated analytical device on a glass chip that performs a protein sizing assay, by integrating the required separation, staining, virtual destaining, and detection steps. To obtain a universal noncovalent fluorescent labeling method, we have combined on-chip dye staining with a novel electrophoretic dilution step. Denatured protein-sodium dodecyl sulfate (SDS) complexes are loaded on a chip and bind a fluorescent dye as the separation begins. At the end of the separation channel, an intersection is used to dilute the SDS below its critical micelle concentration before the detection point. This strongly reduces the background due to dye molecules bound to SDS micelles and also increases the peak amplitude by 1 order of magnitude. Both the on-chip staining and SDS dilution steps occur in the 100-ms time scale and are approximately 10(4) times faster than their conventional counterparts in SDS-PAGE. This represents a much greater speed increase due to microfabrication than has been obtained in other assay steps such as electrophoretic separations. We have designed and tested a microchip capable of sequentially analyzing 11 different samples, with sizing accuracy better than 5% and high sensitivity (30 nM for carbonic anhydrase). 相似文献
62.
Singer Philipp; Boison Detlev; M?hler Hanns; Feldon Joram; Yee Benjamin K. 《Canadian Metallurgical Quarterly》2007,121(5):815
Selective deletion of glycine transporter 1 (GlyT1) in forebrain neurons enhances N-methyl-D-aspartate receptor (NMDAR)-dependent neurotransmission and facilitates associative learning. These effects are attributable to increases in extracellular glycine availability in forebrain neurons due to reduced glycine re-uptake. Using a forebrain- and neuron-specific GlyT1-knockout mouse line (CamKIIαCre; GlyT1tm1.2fl/fI), the authors investigated whether this molecular intervention can affect recognition memory. In a spontaneous object recognition memory test, enhanced preference for a novel object was demonstrated in mutant mice relative to littermate control subjects at a retention interval of 2 hr, but not at 2 min. Furthermore, mutants were responsive to a switch in the relative spatial positions of objects, whereas control subjects were not. These potential procognitive effects were demonstrated against a lack of difference in contextual novelty detection: Mutant and control subjects showed equivalent preference for a novel over a familiar context. Results therefore extend the possible range of potential promnesic effects of specific forebrain neuronal GlyT1 deletion from associative learning to recognition memory and further support the possibility that mnemonic functions can be enhanced by reducing GlyT1 function. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
63.
Tso Yee Fan Ripin D.J. Aggarwal R.L. Ochoa J.R. Bien Chann Tilleman M. Spitzberg J. 《IEEE journal of selected topics in quantum electronics》2007,13(3):448-459
Cryogenically cooled solid-state lasers promise a revolution in power scalability while maintaining a good beam quality because of significant improvements in efficiency and thermo-optic properties. This is particularly true for Yb lasers because of their relatively low quantum defect and relatively broadband absorption even at cryogenic temperatures. Thermo-optic properties of host materials, including thermal conductivity, thermal expansion, and refractive index at low temperature, are reviewed and data presented for YAG (ceramic and single crystal), GGG, GdVO4, and Y2O3. Spectroscopic properties of Yb:YAG and Yb:LiYF4 (YLF) including absorption cross sections, emission cross sections, and fluorescence lifetimes at cryogenic temperatures are characterized. Recent experiments have pushed the power from an end-pumped cryogenically cooled Yb:YAG laser to 455-W continuous-wave output power from 640-W incident pump power at an of M2 1.4. 相似文献
64.
Jose G. Guarnizo Martin Mellado Cheng Yee Low Francisco Blanes 《Advanced Robotics》2013,27(15):989-1004
Coordination strategy is a relevant topic in multi-robot systems, and robot soccer offers a suitable domain to conduct research in multi-robot coordination. Team strategy collects and uses environmental information to derive optimal team reactions, through cooperation among individual soccer robots. This paper presents a diagrammatic approach to architecting the coordination strategy of robot soccer teams by means of a principle solution. The proposed model focuses on robot soccer leagues that possess a central decision-making system, involving the dynamic selection of the roles and behaviors of the robot soccer players. The work sets out from the conceptual design phase, facilitating cross-domain development efforts, where different layers must be interconnected and coordinated to perform multiple tasks. The principle solution allows for intuitive design and the modeling of team strategies in a highly complex robot soccer environment with changing game conditions. Furthermore, such an approach enables systematic realization of collaborative behaviors among the teammates. 相似文献
65.
Heald R. Aingaran K. Amir C. Ang M. Boland M. Dixit P. Gouldsberry G. Greenley D. Grinberg J. Hart J. Horel T. Wen-Jay Hsu Kaku J. Chin Kim Song Kim Klass F. Kwan H. Lauterbach G. Lo R. McIntyre H. Mehta A. Murata D. Nguyen S. Yet-Ping Pai Patel S. Shin K. Tam K. Vishwanthaiah S. Wu J. Yee G. You E. 《Solid-State Circuits, IEEE Journal of》2000,35(11):1526-1538
This quad-issue processor achieves 1-GHz operation through improved dynamic circuit techniques in critical paths and a more extensive on-chip memory system which scales in both bandwidth and latency. Critical logic paths use domino, delayed clocked domino, and logic embedded in dynamic flip-flops for minimum delay. A 64-KB sum-addressed memory data cache combines the address offset add with the cache decode, allowing the average memory latency to scale by more than the clock ratio. Memory bandwidth is improved by using wave pipelined SRAM designs for on-chip caches and a write cache for store traffic. Memory power is controlled without increased latency by use of delayed-reset logic decoders. The chip operates at 1000 MHz and dissipates less than 80 W from a 1.6-V supply. It contains 23 million transistors (12 million in RAM cells) on a 244 mm2 die 相似文献
66.
Single, unreliable machine producing n part types is considered. Using a continuous flow model, conditions are found for the optimality of a just-in-time, or zero-inventory, policy via a stochastic coupling analysis. These conditions are proven to be necessary and conjectured to be sufficient for optimality. This correspondence extends the results of Veatch and Caramanis, in which necessary and sufficient conditions are found for a single machine producing two part types, and it strengthens the results of Perkins and Srikant, in which sufficient conditions are found for n part types 相似文献
67.
Csomor Philipp A.; Yee Benjamin K.; Vollenweider Franz X.; Feldon Joram; Nicolet Tiana; Quednow Boris B. 《Canadian Metallurgical Quarterly》2008,122(4):885
Prepulse inhibition (PPI) of the startle reflex refers to the reduction of the reflexive startle response to an intense pulse stimulus when its presentation is shortly preceded by a weak prepulse stimulus. PPI is considered as a cross-species translational model of sensorimotor gating, and deficient PPI has been reported in a number of neuropsychiatric disorders. Although a part of the literature is based on the assumption that PPI is independent of the baseline startle reaction, there is accumulating evidence (Csomor et al., 2006; Sandner & Canal, 2007; Yee, Chang, Pietropaolo, & Feldon, 2005) that argues against such an independency. The authors systematically investigated whether PPI indexed as percentage or difference score is dependent on the magnitude of baseline startle reactivity in healthy human volunteers and in C57BL/6 mice. The results revealed that both indexations of PPI were affected by the magnitude of the baseline startle. The authors highlight the pitfalls of different methods to index PPI, especially when startle reactivity differs considerably between groups under comparison, and offer practical recommendations to satisfactorily deal with such baseline differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
68.
Yee Li Kang Mei Yi Poon Purushothaman Monash Shaliza Ibrahim Pichiah Saravanan 《Korean Journal of Chemical Engineering》2013,30(10):1904-1910
A detailed surface characterizations and adsorption mechanism of Cd2+ on chemical activated carbon (CAC) prepared from Garnicia mangostana shell were investigated. The activation is accomplished in self-generating atmosphere using phosphoric acid as activating agent. The characterizations performed are elemental analysis, functional group identification, N2 adsorption isotherm and surface charges. Adsorption mechanism of metal ion was tested using Cd2+ as model ion. CAC achieved BET surface area of 1,498 m2/g with a mixture of micro and mesopores. The point of zero charge is observed to be at pH 2.8 and the optimum pH for Cd2+ adsorption on CAC is 12. The adsorption isotherm followed the Freundlich model, and the adsorption kinetics was explained by pseudo-second order kinetic model. From thermodynamic studies, the adsorption was found to be physical adsorption. X-ray photoelectron spectroscopy (XPS) confirmed the adsorption of Cd2+ onto CAC as +2 oxidation state. 相似文献
69.
Klass F. Amir C. Das A. Aingaran K. Truong C. Wang R. Mehta A. Heald R. Yee G. 《Solid-State Circuits, IEEE Journal of》1999,34(5):712-716
In an attempt to reduce the pipeline overhead, a new family of edge-triggered flip-flops has been developed. The flip-flops belong to a class of semidynamic and dynamic circuits that can interface to both static and dynamic circuits. The main features of the basic design are short latency, small clock load, small area, and a single-phase clock scheme. Furthermore, the flip-flop family has the capability of easily incorporating logic functions with a small delay penalty. This feature greatly reduces the pipeline overhead, since each flip-flop can be viewed as a special logic gate that serves as a synchronization element as well 相似文献
70.
Li-Na Zhao Xue-Feng Wang Zhen-Hua Yao Zhu-Feng Hou Marcus Yee Xing Zhou Shi-Huan Lin Teck-Seng Lee 《Journal of Computational Electronics》2008,7(4):500-508
A first-principle model is proposed to study the electrostatic properties of a double-gated silicon slab of nano scale in
the framework of density functional theory. The applied gate voltage is approximated as a variation of the electrostatic potential
on the boundary of the supercell enclosing the system. With the electron density estimated by the real space Green’s functions,
efficient multigrid and fast Fourier-Poisson solvers are employed to calculate the electrostatic potential from the charge
density. In the representation of localized SIESTA linear combination of atomic orbitals, the Kohn-Sham equation is established
and solved self-consistently for the wavefunction of the system in the local density approximation. The transmission for ballistic
transport across the atomic silicon slab at small bias is calculated. The charge distribution and electrostatic potential
profile in the silicon slab versus the gate voltage are then analyzed with the help of the equivalent capacitive model. Quantum
confinement and short gate effects are observed and discussed. 相似文献