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排序方式: 共有333条查询结果,搜索用时 15 毫秒
61.
JE Thole B Wieles JE Clark-Curtiss TH Ottenhoff TF Rinke de Wit 《Canadian Metallurgical Quarterly》1995,18(5):791-800
A major focus of leprosy research in the last 10 years has been the identification and characterization of antigens of Mycobacterium leprae that interact with antibodies and T cells of the host's immune response. Through the combined efforts of many different laboratories, a substantial number of protein antigens have been identified and characterized. In this MicroReview we present an updated list of M. leprae protein antigens, and, with emphasis on recent developments, summarize what is known regarding their functional and immunological features. 相似文献
62.
Chutuape Mary Ann D.; Mitchell Suzanne H.; de Wit Harriet 《Canadian Metallurgical Quarterly》1994,2(4):310
Ethanol (ETOH) preference was measured following ETOH preload doses in normal social drinkers. 11 Ss participated in a 5-session, double-blind choice study. In Session 1, Ss sampled an ETOH beverage (0.8 g/kg). In Sessions 2–5, they consumed a preload beverage containing placebo or ETOH (0.25 or 0.5 g/kg). One hour later, they responded on 2 concurrent random-ratio (RR) schedules. One schedule was associated with ETOH as the reinforcer and the other with money. When the probability of earning money was low, Ss responded more on the ETOH schedule following both ETOH preloads compared with placebo. Consistent with the increased responding for ETOH, Ss reported increased desire for ETOH. These data demonstrate a priming effect of ETOH preloads in normal social drinkers. They also illustrate the use of concurrent RR schedules to quantify ETOH preference. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
63.
Christoph Koepple Zizi Zhou Lena Huber Matthias Schulte Kjestine Schmidt Torsten Gloe Ulrich Kneser Volker Jürgen Schmidt Cor de Wit 《International journal of molecular sciences》2021,22(14)
Connexins (Cx) form gap junctions (GJ) and allow for intercellular communication. However, these proteins also modulate gene expression, growth, and cell migration. The downregulation of Cx43 impairs endothelial cell migration and angiogenetic potential. Conversely, endothelial Cx43 expression is upregulated in an in vivo angiogenesis model relying on hemodynamic forces. We studied the effects of Cx43 expression on tube formation and proliferation in HUVECs and examined its dependency on GJ communication. Expectedly, intercellular communication assessed by dye transfer was linked to Cx43 expression levels in HUVECs and was sensitive to a GJ blockade by the Cx43 mimetic peptide Gap27. The proliferation of HUVECs was not affected by Cx43 overexpression using Cx43 cDNA transfection, siRNA-mediated knockdown of Cx43, or the inhibition of GJ compared to the controls (transfection of an empty vector, scrambled siRNA, and the solvent). In contrast, endothelial tube and sprout formation in HUVECs was minimized after Cx43 knockdown and significantly enhanced after Cx43 overexpression. This was not affected by a GJ blockade (Gap27). We conclude that Cx43 expression positively modulates the angiogenic potential of endothelial cells independent of GJ communication. Since proliferation remained unaffected, we suggest that Cx43 protein may modulate endothelial cell migration, thereby supporting angiogenesis. The modulation of Cx43 expression may represent an exploitable principle for angiogenesis induction in clinical therapy. 相似文献
64.
Channel hot carrier (CHC) degradation is one of the major reliability concerns for nanoscale transistors. To simulate the impact of CHC on analog circuits, a unified analytical model able to cope with various design and process parameters is proposed. In addition, our model can handle initial degradation and varying stress conditions, allowing the designer to estimate the impact of CHC on transistor performance for arbitrary stressing patterns. The model is experimentally verified in a 65 nm CMOS technology. Expressions to simulate the impact of transistor degradation on relevant transistor parameters like output conductance and threshold voltage degradation are presented and verified. 相似文献
65.
The phenomenology of shrinkage is established through injection molding experiments in which shrinkage was measured at 25‐mm intervals along the length and width of rectangular plaques, molded in an instrumented mold. A simple solidification model, which assumes the solidified material to be elastic, is developed for the effect of time‐varying temperature and pressure histories on part shrinkage. This model predicts a linear dependence of shrinkage on an “effective pressure,” which combines the thermal diffusivity of the material, the wall thickness, and the time‐varying cavity pressure into a single parameter that is uniquely related to the shrinkage. The effective pressure is shown to effectively correlate in‐plane shrinkage data. The solidification model characterizes two material parameters, which can be estimated from the pressure‐volume‐temperature (PVT) diagram for the material, that describe the sensitivity of the shrinkage to the local cavity pressure history. The residual stresses predicted by this model are rather crude. POLYM. ENG. SCI., 59:1648–1656 2019. © 2019 Society of Plastics Engineers 相似文献
66.
Rianne van den Berghe Mirjam de Haas Ora Oudgenoeg-Paz Emiel Krahmer Josje Verhagen Paul Vogt Bram Willemsen Jan de Wit Paul Leseman 《Journal of Computer Assisted Learning》2021,37(2):396-410
This study investigates the degree to which children anthropomorphize a robot tutor and whether this anthropomorphism relates to their vocabulary learning in a second-language (L2) tutoring intervention. With this aim, an anthropomorphism questionnaire was administered to 5-year-old children (N = 104) twice: prior to and following a seven-session L2 vocabulary training with a humanoid robot. On average, children tended to anthropomorphize the robot prior to and after the lessons to a similar degree, but many children changed their attributed anthropomorphic features. Boys anthropomorphized the robot less after the lessons than girls. Moreover, there was a weak but significant positive correlation between anthropomorphism as measured before the lessons and scores on a word-knowledge post-test administered the day after the last lesson. There was also a weak but significant positive correlation between the change in anthropomorphism over time and scores on a word-knowledge post-test administered approximately 2 weeks after the last lesson. Our results underscore the need to manage children's expectations in robot-assisted education. Also, future research could explore adaptations to individual children's expectations in child-robot interactions. 相似文献
67.
A finite difference method was proposed to model the effect of a variety of tool coatings on the magnitude and distribution of temperatures through the tool-chip contact region and the coating/substrate boundaries. For each workpiece-tool pair tested the intensity of uniformly distributed heat flux and relevant analytically obtained values of the heat partition coefficient were assumed to change with variations of cutting speed and the corresponding friction. In this case the simulation of an orthogonal machining of AISI 1045 steel was performed using special computing algorithm with elementary balances of induced energies (MBE). It is concluded that the temperature contours obtained reflect favorable the specific contact conditions existing at the tool-chip interface and substantial differences can arise from coating effects. 相似文献
68.
The results of conformal pin-on-disc tribological tests of a hard layer of the solid solution of oxygen in α-titanium sliding against a Co–28Cr–5W–4Fe–3Ni–1Si cobalt alloy counterspecimen are presented. The α-Ti(O) layer was diffusely produced over 2–8 h of oxidising in the superficial zone of a technical quality titanium specimen.The friction and wear responses of the system were recorded and the wear mechanisms were studied. Investigations of the material structure and chemical constitution in micro-areas of the titanium specimen, cobalt alloy counterspecimen and wear debris formed in dry sliding were performed with a Philips XL20 microscope equipped with an EDAX analyser. Crushing of the α-Ti(O) layer, lowering of the wear rate after comminution of the hard α-Ti(O) layer, local tack spots and fine powder wear particles, mostly Ti oxides, were detected at the beginning of each test. Gradual brittle fracture and decay by pulverising of the α-Ti(O) particles embedded in both mating surfaces, which occurred during the test, led to the increase of the wear rate of the couple and domination of microcutting and tack spots spalling after their partial oxidation. Finally, after the disappearance of the α-Ti(O) loose particles, adhesive junctions, metal transfer and smearing become leading wear mechanisms. 相似文献
69.
ABSTRACT A finite difference method was proposed to model the effect of a variety of tool coatings on the magnitude and distribution of temperatures through the tool-chip contact region and the coating/substrate boundaries. For each workpiece-tool pair tested the intensity of uniformly distributed heat flux and relevant analytically obtained values of the heat partition coefficient were assumed to change with variations of cutting speed and the corresponding friction. In this case the simulation of an orthogonal machining of AISI 1045 steel was performed using special computing algorithm with elementary balances of induced energies (MBE). It is concluded that the temperature contours obtained reflect favorable the specific contact conditions existing at the tool-chip interface and substantial differences can arise from coating effects. 相似文献
70.
This paper presents a nonlinear control design for both the H2 and H∞ optimal control for current-fed induction motor drives. These controllers are derived using analytical stationary solutions that minimize a generalized convex energy cost function including the stored magnetic energy and the coil losses, while satisfying torque regulation control objectives. Explicit control expressions for both the H2 and H∞ optimal design are given. Furthermore, the optimal attenuation factor, i.e., the optimal H∞ norm and the corresponding worst case disturbance, are both computed explicitly 相似文献