Fully differential operational amplifiers using CMOS compatible lateral bipolar transistors with improved common-mode regulation

A new bias circuit for a CMOS compatible lateral bipolar transistor differential pair is presented. The circuit compensates for all process and bias dependent variations of the lateral collector current to emitter current ratio alpha . Experimental results show that its application to a fully differential amplifier improves the precision of the common-mode output voltage regulation by at least an order of magnitude.<>     

High-speed switching of monolithic arrays ofgrating-surface-emitting diode lasers

The electrooptic switching properties of injection-coupled coherent two-dimensional grating-surface-emitting (GSE) laser arrays with multiple gain sections and quantum-well active layers are discussed. Within such an array of injection-coupled GSE lasers, a single gain section can act as an intracavity saturable loss element that can modulate the output of the entire array. Experimental results demonstrate efficient subnanosecond switching of high-power GSE laser arrays by operating only one gain section as an intracavity loss modulator     

Coherent lightwave systems for interoffice and loop-feeder applications

Coherent lightwave systems offer the potential for providing many closely spaced multigigabit channels. This is attractive for interoffice and loop-feeder applications, provided the resulting systems are based on a robust technology and incorporate a high level of integration. Further research is needed for coherent lightwave technology to become commercially viable in these applications, especially in the areas of device performance, multichannel capability, level of integration, and transmission speed.     

A Boundary Element Analysis of Quasi-Brittle Solids Containing Cracks

Quasi-brittle solids usually contain many cracks. When numerical methods are used, it is difficult to simulate all the cracks’ behaviors, especially when the crack propagation is included. To surmount the difficulty, a new procedure combining the subdomain boundary element method and the generalized self-consistent scheme is presented. The behavior of a single crack is analyzed first. The obtained information is then used to predict the overall behavior of the cracked solids. The relationship between the overall response of the cracked solids and the growth of wing cracks is established numerically. A cohesive-crack model is used to simulate the fracture process zone of the quasi-brittle solids. Besides, the advancement of the wing crack tip is used as a control variable. An incremental iteration algorithm is developed to trace the growth of the wing (secondary) cracks, which is not known a priori. The influence of the crack angle and the friction coefficient on the effective moduli is also investigated. Finally, a gypsum square plate containing orderly distributed cracks is analyzed to illustrate the adequacy and efficiency of the present procedure.     

Brain abscess in solid organ transplant recipients receiving cyclosporine-based immunosuppression

There is currently a stark therapeutic void in the treatment of evolving stroke. Although P-selectin is rapidly expressed by hypoxic endothelial cells in vitro, the functional significance of P-selectin expression in stroke remains unexplored. In order to identify the pathophysiological consequences of P-selectin expression and to identify P-selectin blockade as a potential new approach for the treatment of stroke, experiments were performed using a murine model of focal cerebral ischemia and reperfusion. Early P-selectin expression in the postischemic cerebral cortex was demonstrated by the specific accumulation of radiolabeled anti-murine P-selectin IgG, with the increased P-selectin expression localized to the ipsilateral cerebral microvascular endothelial cells by immunohistochemistry. In experiments designed to test the functional significance of increased P-selectin expression in stroke, neutrophil accumulation in the ischemic cortex of mice expressing the P-selectin gene (PS +/+) was demonstrated to be significantly greater than that in homozygous P-selectin-null mice (PS -/-). Reduced neutrophil influx was accompanied by greater postischemic cerebral reflow (measured by laser Doppler) in the PS -/- mice. In addition, PS -/- mice demonstrated smaller infarct volumes (5-fold reduction, P<.05) and improved survival compared with PS +/+ mice (88% versus 44%, P<.05). Functional blockade of P-selectin in PS +/+ mice using a monoclonal antibody directed against murine P-selectin also improved early reflow and stroke outcome compared with control mice, with reduced cerebral infarction volumes noted even when the blocking antibody was administered after occlusion of the middle cerebral artery. These data are the first to demonstrate a pathophysiological role for P-selectin in stroke and suggest that P-selectin blockade may represent a new therapeutic target in the treatment of stroke.     

原装德国SPS(R) PEH先进刮胶技术

每台SPS STOP滚筒丝网印刷机都拥有一个独特的PEH(气压、电动、液压式)刮胶系统.该创新技术及精密结构一经问世,就成为诸多网印设备制造商竞相模仿的对象,但直到今天,仍没有一项其他技术可与之相媲美,也因此,SPS仍牢牢占据市场领导地位.     

Experimental Observation of the Relationship Between the Meissner Effect and the ac Magnetic Susceptibility

Meissner diamagnetic effect is a basic criterion for identifying whether a matter is superconducting or not. However, currently one of main methods to measure magnetic property of a superconductor is ac mutual inductance technique by which ac magnetic susceptibility is measured. To investigate the relation between Meissner diamagnetic effect and the diamagnetism measured by ac susceptibility, we designed and performed an ac susceptibility experiment, that is, ac susceptibility of a superconductor as a function of temperature is measured under a constant dc magnetic field. Our experimental result shows that bulk and surface diamagnetism cannot occur in a superconductor simultaneously. This conclusion further proves that the signal of ac magnetic susceptibility gives no evidence for Meissner effect. Microscopic model and analysis on bulk and surface superconducting diamagnetism was given in the present paper.     

Inhibition of reaper-induced apoptosis by interaction with inhibitor of apoptosis proteins (IAPs)

IAPs comprise a family of inhibitors of apoptosis found in viruses and animals. In vivo binding studies demonstrated that both baculovirus and Drosophila IAPs physically interact with an apoptosis-inducing protein of Drosophila, Reaper (RPR), through their baculovirus IAP repeat (BIR) region. Expression of IAPs blocked RPR-induced apoptosis and resulted in the accumulation of RPR in punctate perinuclear locations which coincided with IAP localization. When expressed alone, RPR rapidly disappeared from the cells undergoing RPR-induced apoptosis. Expression of P35, a caspase inhibitor, also blocked RPR-induced apoptosis and delayed RPR decline, but RPR remained cytoplasmic in its location. Mutational analysis of RPR demonstrated that caspases were not directly responsible for RPR disappearance. The physical interaction of IAPs with RPR provides a molecular mechanism for IAP inhibition of RPR's apoptotic activity.