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排序方式: 共有280条查询结果,搜索用时 15 毫秒
1.
MQ Fujita N Hashida M Shin H Nakanishi W Yoshihara K Aozasa 《Canadian Metallurgical Quarterly》1998,55(6):600-606
Poly(A)+ mRNA was isolated from leaves of potato plants (Solanum tuberosum L. cv. Desiree) according to standard protocols. This poly(A)+ mRNA was injected via glass microcapillaries into oocytes that were surgically removed from the African clawed toad Xenopus laevis. As a control, oocytes were either injected with H2O or remained untreated. Three days after injection the oocytes were analyzed by two electrode voltage clamping. Current voltage analysis revealed that a K+ channel from potato was functionally expressed in injected oocytes. The identity of this K+ channel was confirmed by its substrate specificity and a shift in the reversal potential. In particular, when the outside K+ concentration was increased the reversal potential of poly(A)+ injected oocytes shifted to more positive values. Furthermore, K+ outward currents declined when the outside K+ concentration was raised from 0.1 to 100 mM. Inward currents increased with an elevation of the K+ concentration. Several pharmaceuticals were tested for their potential to block this K+ channel. As a result, the channel was completely blocked by BaCl2. A three state reaction kinetic model was used to simulate the currents through the K+ transport protein as function of the extracellular K+ concentration. In particular, the simulation revealed current voltage relations that exactly matched the measured ones. Saturation of current voltage curves emerged from the simulation as a consequence of high extracellular potassium concentration. 相似文献
2.
Ming Chuang Linjie Luo Benedict J. Brown Szymon Rusinkiewicz Michael Kazhdan 《Computer Graphics Forum》2009,28(5):1475-1484
We present a novel approach for computing and solving the Poisson equation over the surface of a mesh. As in previous approaches, we define the Laplace-Beltrami operator by considering the derivatives of functions defined on the mesh. However, in this work, we explore a choice of functions that is decoupled from the tessellation. Specifically, we use basis functions (second-order tensor-product B-splines) defined over 3D space, and then restrict them to the surface. We show that in addition to being invariant to mesh topology, this definition of the Laplace-Beltrami operator allows a natural multiresolution structure on the function space that is independent of the mesh structure, enabling the use of a simple multigrid implementation for solving the Poisson equation. 相似文献
3.
Summary Carrier sense multiple access (CSMA) protocols were originally conceived for use in digital radio communication. Such protocols are, however, quite applicable in a variety of distributed computing and local networking configurations based on a shared bus. The CSMA protocols are characterized by the fact that message collisions can occur only in a very small time window whose duration corresponds to the propagation delay of the bus. They are further characterized by the technique used to subsequently serialize the transmission of the colliding messages. In this paper we analyze the situation wherein colliding messages are serialized by using a set of staggered retry delays which are associated with the sources that may generate the colliding messages. Our analysis produces both path throughput (utilization) curves and message delay curves, as a function of message generation rate. These curves show that the protocol is in a sense self stabalizing, serve to quantify its behaviour, and indicate loading levels which result in unacceptable message delays. 相似文献
4.
Stankovic A.V. Benedict E.L. John V. Lipo T.A. 《Industry Applications, IEEE Transactions on》2003,39(5):1257-1263
This paper presents a novel method for measuring the magnetizing inductance of an induction machine. The approach uses a static DC excitation technique which can be employed whenever the neutral of the machine is accessible. The proposed method measures only the magnetizing inductance and not the self inductance which normally includes the effect of the stator leakage inductance. Because this test uses a DC excitation, the iron losses in the motor are considerably reduced as well and minimally influence the measurement when compared to the traditional 60-Hz no-load test. By using the proposed method for measuring only the magnetizing inductance, the stator leakage inductance can be later individually determined by performing a separate no-load test. Test results using the method are compared with theoretical values and confirm its feasibility. 相似文献
5.
Hyunjong Byun Jiyeon Park Benedict U. Fabia Joshua Bingwa Mihn Hieu Nguyen Haeshin Lee Jung Hoon Ahn 《International journal of molecular sciences》2022,23(12)
Many heterologous proteins can be secreted by bacterial ATP-binding cassette (ABC) transporters, provided that they are fused with the C-terminal signal sequence, but some proteins are not secretable even though they carry the right signal sequence. The invention of a method to secrete these non-secretable proteins would be valuable both for understanding the secretory physiology of ABC transporters and for industrial applications. Herein, we postulate that cationic “supercharged” regions within the target substrate protein block the secretion by ABC transporters. We also suggest that the secretion of such substrate proteins can be rescued by neutralizing those cationic supercharged regions via structure-preserving point mutageneses. Surface-protruding, non-structural cationic amino acids within the cationic supercharged regions were replaced by anionic or neutral hydrophilic amino acids, reducing the cationic charge density. The examples of rescued secretions we provide include the spike protein of SARS-CoV-2, glutathione-S-transferase, streptavidin, lipase, tyrosinase, cutinase, growth factors, etc. In summary, our study provides a method to predict the secretability and a tool to rescue the secretion by correcting the secretion-blocking regions, making a significant step in understanding the physiological properties of ABC transporter-dependent protein secretion and laying the foundation for the development of a secretion-based protein-producing platform. 相似文献
6.
Thermal analysis of randomly oriented carbon nanotube reinforced functionally graded timoshenko beam
Benedict Thomas Prasad K. Inamdar Tarapada Roy 《Journal of Mechanical Science and Technology》2014,28(5):1779-1788
The unique thermal properties of carbon nanotubes (CNT) are utilized to increase the use of functionally graded material (FGM) at higher temperatures which resulted in introduction of a new type of material called as functionally graded carbon nanotube-reinforced composites (FG-CNTRCs). To use the FG-CNTRCs at elevated temperatures, their thermal analysis is very important. In this context, this article presents the thermal analysis of a CNT based FG Timoshenko beam. Material properties distribution is assumed to vary along the thickness direction according to power law distribution and linear distributions. Finite difference method is implemented to find out the temperature distribution. Using first order shear deformation theory (FSDT), expressions for strains and stresses are obtained. The results are compared with temperature distribution according to power law. The effect of CNT distribution on strains and stresses is also observed. Based on these results important conclusions have been drawn. 相似文献
7.
David Kelly Benedict Ilozor 《International Journal of Construction Education and Research》2019,15(1):3-18
This article reports the findings of a quantitative study on the relationship between various project performance outcomes and the use of Building Information Modeling (BIM), within the commercial construction industry. The literature review identified inconsistent results among prior qualitative and quantitative work concerning the relationships of key project performance measures and BIM use. Data on 13 variables from 93 completed construction projects were collected and examined through a causal comparative research design. Projects that used BIM (in design or construction) were not found to experience significant performance outcomes when controlling for the contribution of other independent variables and covariates at the 95% confidence level (CL). At the lower 90% CL, however, projects using BIM in construction experienced significantly higher levels of schedule growth than projects that did not use BIM in construction. Recommendations are made for training of construction management staff as a step to avoid unwanted schedule growth associated with BIM use during construction. This study is one of a very small group of rigorous quantitative analyses of BIM project performance outcomes conducted to date; additionally, it is the only study that has analyzed BIM in a multivariate context that controlled for the contribution of other project variables not directly related to BIM use. 相似文献
8.
Vettiger P. Benedict M.K. Bona G.-L. Buchmann P. Cahoon E.C. Datwyler K. Dietrich H.-P. Moser A. Seitz H.K. Voegeli O. Webb D.J. Wolf P. 《Quantum Electronics, IEEE Journal of》1991,27(6):1319-1331
A concept for full-wafer processing (FWP) and full-wafer testing (FWT) for semiconductor laser fabrication in the AlGaAs-GaAs material system is presented. The approach is based on chemically assisted ion beam etching for the laser-mirror formation. Record values for mirror scattering, optimum mirror reflectivity, and equivalence to cleaved mirrors in terms of laser threshold and efficiency have been achieved. Promising results for uniformity and reproducibility for major laser diode characteristics on processed 2-in wafers have been found. The FWP technology has been extensively used for designing test sites to determine various materials, process, and laser parameters, such as sheet resistance, ridge dimensions, lithographic alignment errors, mirror surface leakage, etc 相似文献
9.
Equine practitioners should be knowledgeable of dental anatomy and development to enhance their skill of age estimation of horses. The permanent teeth of horses are continually undergoing changes in shape and appearance. These changes may be used to suggest a reasonable age range for a horse. 相似文献
10.
The total potential energy for a body composed of an anisotropic micropolar linear elastic material is developed and used to formulate a displacement type finite element method of analysis. As an example of this formulation triangular plane stress (and plane couple stress) elements are used to analyze several problems. The program is verified by computing the stress concentration around a hole in an isotropic micropolar material for which an exact analytical solution exists. Several anisotropic material cases are presented which demonstrate the dependence of the stress concentration factor on the micropolar material parameters. 相似文献