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81.
Feltin E. Christmann G. Dorsaz J. Castiglia A. Carlin J.-F. Butte R. Grandjean N. Christopoulos S. Baldassarri G. von Hogersthal H. Grundy A.J.D. Lagoudakis P.G. Baumberg J.J. 《Electronics letters》2007,43(17):924-926
Laser action with low threshold average pump power density (~50 W - cm-2 ) at room temperature is reported for a crack-free planar vertical cavity surface emitting laser (VCSEL) structure based on a bottom lattice-matched AllnN/GaN distributed Bragg reflector (DBR) and a top dielectric DBR. The cavity region, formed by n- and p-type GaN layers surrounding only three InGaN/GaN quantum wells, corresponds to a typical active region suitable for an electrically driven VCSEL. In addition to low threshold, a spontaneous emission coupling factor beta ~ 2 x 10-10 is derived for this ready-to-be-processed laser structure. 相似文献
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L. J. Kutz PhD PE V. P. Nelson 《The International Journal of Advanced Manufacturing Technology》1991,6(4):317-327
The automated control of manufacturing devices on a common communications network is a necessity for the factory of the future.
The manufacturing automation protocol (MAP) represents a major effort by a group of companies towards meeting this need, and
apparently is becoming a standard for factory-floor communications. In this project, an ASEA 2000 robot was used with a computer-controlled
ply-cutting machine in a simulated factory sheet-metal cell to demonstrate coordinated inter- and intra-cell communications.
Both machines used a MAP network to send and receive information from the cell-controller computer, and to coordinate cell
operation. The methodology, hardware and software required to adapt the ASEA robot to the MAP network are described. This
methodology will be useful in adapting other computer-controlled manufacturing devices to MAP networks. 相似文献
83.
AG Brooks F Borrego PE Posch A Patamawenu CJ Scorzelli M Ulbrecht EH Weiss JE Coligan 《Canadian Metallurgical Quarterly》1999,162(1):305-313
The CD94/NKG2 receptors expressed by subpopulations of NK cells and T cells have been implicated as receptors for a broad range of both classical and nonclassical HLA class I molecules. To examine the ligand specificity of CD94/NKG2 proteins, a soluble heterodimeric form of the receptor was produced and used in direct binding studies with cells expressing defined HLA class I/peptide complexes. We confirm that CD94/NKG2A specifically interacts with HLA-E and demonstrate that this interaction is dependent on the association of HLA-E with peptide. Moreover, no interaction between CD94/NKG2A and classical HLA class I molecules was observed, as assayed by direct binding of the soluble receptor or by functional assays using CD94/NKG2A+ NK cells. The role of the peptide associated with HLA-E in the interaction between HLA-E and CD94/NKG2A was also assessed. All class I leader sequence peptides tested bound to HLA-E and were recognized by CD94/NKG2A. However, amino acid variations in class I leader sequences affected the stability of HLA-E. Additionally, not all HLA-E/peptide complexes examined were recognized by CD94/NKG2A. Thus CD94/NKG2A recognition of HLA-E is controlled by peptide at two levels; first, peptide must stabilize HLA-E and promote cell surface expression, and second, the HLA-E/peptide complex must form the ligand for CD94/NKG2A. 相似文献
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This tenth anniversary review/update of fluoxetine concentrates on the past 5 years of its clinical application. The mechanism of action of fluoxetine; its metabolism; its efficacy in patients with various diagnostic subgroups of depression, patients with coincident medical disease, children and adolescents with depression, patients with eating disorders, and patients with obsessive-compulsive disorder (OCD); its long-term (maintenance) efficacy; its side effects and toxicity; and pharmacoeconomic considerations are reviewed. Pharmacotherapy is currently the only proven method for treating major depressive disorder that is applicable to all levels of severity of major depressive illness. Since its introduction 10 years ago, fluoxetine has been available to psychiatrists, primary care physicians, and other nonpsychiatric physicians as full-dose effective pharmacotherapy for patients with depression. Fluoxetine has been widely prescribed by physicians knowledgeable in pharmacology and in the treatment of depression because of its proven efficacy (ie, equal to that of tricyclic antidepressants [TCAs]), its ease of administration (with full therapeutic dosing usually starting from day 1), its generally benign side-effect profile, its remarkable safety in over-dose, and its proven effectiveness in the most common depressed patient population--anxious, agitated, depressed patients--as well as in patients with various subtypes and severities of depression. In more recent years it has also proved effective in the treatment of bulimia, an entity for which only limited or inadequate treatment options had been previously available. In OCD, fluoxetine, with its more acceptable side-effect profile and greater ease of dosing, presents a favorable alternative to previous drug therapy and is useful in treating both obsessions and compulsions. Fluoxetine is currently recognized among clinicians as efficacious in treating anxiety disorders and is being used successfully in special depressed populations such as patients with medical comorbidity, elderly patients, adolescents, and children. Rapid discontinuation or missed doses of short-half-life selective serotonin reuptake inhibitors, TCAs, and heterocyclic antidepressants are associated with withdrawal symptoms of a somatic and psychological nature, which cannot only be disruptive, but can also be suggestive of relapse or recurrence of depression. In striking contrast to these short-half-life antidepressants, fluoxetine is rarely associated with such sequelae on sudden discontinuation or missed doses. This preventive effect against withdrawal symptoms on discontinuation of fluoxetine is attributed to the unique extended half-life of this antidepressant. Current studies show that the overall increased effectiveness of fluoxetine in treating depression compensates for its higher cost, compared with older drugs, by reducing the need for physician contact because of increased compliance and less need of titration, and by reducing premature patient discontinuation, thereby yielding fewer relapses, less recurrence, and less reutilization of mental health services. 相似文献
87.
Protein structure alignment by incremental combinatorial extension (CE) of the optimal path 总被引:19,自引:0,他引:19
A new algorithm is reported which builds an alignment between two protein
structures. The algorithm involves a combinatorial extension (CE) of an
alignment path defined by aligned fragment pairs (AFPs) rather than the
more conventional techniques using dynamic programming and Monte Carlo
optimization. AFPs, as the name suggests, are pairs of fragments, one from
each protein, which confer structure similarity. AFPs are based on local
geometry, rather than global features such as orientation of secondary
structures and overall topology. Combinations of AFPs that represent
possible continuous alignment paths are selectively extended or discarded
thereby leading to a single optimal alignment. The algorithm is fast and
accurate in finding an optimal structure alignment and hence suitable for
database scanning and detailed analysis of large protein families. The
method has been tested and compared with results from Dali and VAST using a
representative sample of similar structures. Several new structural
similarities not detected by these other methods are reported. Specific
one-on-one alignments and searches against all structures as found in the
Protein Data Bank (PDB) can be performed via the Web at
http://cl.sdsc.edu/ce.html.
相似文献
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