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141.
Describes a method for generating a one-stage, one-sided switching network with the minimum number of switches for any required level of connectivity. The fact that the method generates optimal networks is established by proving appropriate lower bounds. This generalises recent work of Newbury 相似文献
142.
143.
H Okada J Woodcock-Mitchell J Mitchell T Sakamoto K Marutsuka BE Sobel S Fujii 《Canadian Metallurgical Quarterly》1998,97(21):2175-2182
BACKGROUND: Ischemia with or without reperfusion induces the release of diverse products from monocytes, including cytokines such as interleukin-1 (IL-1). To determine whether these phenomena modulate fibrinolysis and potentially exacerbate impairment of the macrocirculation, microcirculation, or both, we characterized the effects of IL-1 on the expression of fibrinolytic system and matrix proteins in rat cardiac microvascular endothelial cells (CMECs). METHODS AND RESULTS: Confluent CMECs were exposed to IL-1 in serum-free medium for 24 hours, and cell-conditioned medium was assayed for plasminogen activator inhibitor type 1 (PAI-1), the primary physiological inhibitor of plasminogen activators, and for type 1 collagen with Western blotting. IL-1 (2 ng/mL) specifically increased the accumulation of PAI-1 (4.4 +/- 0.6-fold; mean +/- SD; n = 9) without affecting tissue plasminogen activator (t-PA) or urokinase plasminogen activator (u-PA) levels, which remained unchanged. IL-1 increased the accumulation of collagen in conditioned media by 3.5 +/- 0.7-fold (n = 6). Conversely, the accumulation of both PAI-1 and collagen induced by IL-1 was inhibited with an IL-1 receptor antagonist (200 ng/mL; n = 6) and with cycloheximide (10 micrograms/mL; n = 6), implying that protein synthesis was a requirement for the effect. To determine whether the IL-1 effect was mediated by induction of oxygen-centered free radical production, known to be induced by IL-1, we exposed the cells to the hydroxyl radical scavenger tetramethylthiourea (10 mmol/L) and observed abolition of the IL-1-induced increase in the expression of PAI-1 and collagen (n = 6). Conversely, superoxides (generated with 10 mU/mL xanthine oxidase plus 0.6 mmol/L hypoxanthine, and 100 mumol/L hydrogen peroxide) induced the accumulation of PAI-1 and collagen (n = 6). IL-1 (1 microgram/kg body wt) and lipopolysaccharide (50 micrograms/kg body wt) administered in vivo increased PAI-1 protein in rat hearts as detected with Western blotting and PAI-1 immunostaining of rat heart microvessels, indicating the effects delineated in vitro were paralleled by effects in vivo. CONCLUSIONS: These results indicate that IL-1-induced oxygen-centered free radicals stimulate elaboration of PAI-1 and collagen by CMECs. Accordingly, microvascularly mediated inhibition of fibrinolysis may predispose to the persistence of microvascular thrombi, thereby contributing to impaired microcirculatory function, the no-reflow phenomenon, and cardiac dysfunction after ischemia and reperfusion. 相似文献
144.
CB Peterson JE Mitchell S Engbloom S Nugent MP Mussell JP Miller 《Canadian Metallurgical Quarterly》1998,24(2):125-136
A new enzymatic assay for selectively measuring conjugated bilirubin concentration in serum with use of bilirubin oxidase (BOD) has been developed. At pH 5.5 BOD can oxidize only conjugated bilirubin in the presence of reagents such as sodium fluoride and N-acetylcysteine which can decrease BOD reactivity to unconjugated bilirubin and bilirubin covalently bound to albumin (delta bilirubin). The resulting decrease in absorbance at 450 nm is linearly related to the concentration of conjugated bilirubin in serum. The BOD in this new assay was confirmed to oxidize conjugated bilirubin, and neither unconjugated nor delta bilirubin, based on both its reactivity to unconjugated bilirubin and HPLC results. This assay was found to give satisfactory results, such as in terms of the range of measurement, the reproducibility of the results, the lack of interference with coexisting substances in serum and the stability of the reagent solutions, in practical applications. The serum conjugated bilirubin concentrations determined using this assay correlate well with those determined by the HPLC analysis. This assay can be used for accurate monitoring of changes in the conjugated bilirubin concentration in patient sera. These findings suggest that the conjugated bilirubin assay is useful for fractional determination of bilirubin in icteric sera. 相似文献
145.
146.
E. N. Houstis W. F. Mitchell T. S. Papatheodorou 《International journal for numerical methods in engineering》1983,19(5):665-709
A number of numerical methods for mildly nonlinear elliptic boundary value problems on general domains is presented. The discretization procedures considered are: a fourth-order FFT-type method, collocation using Hermite bicubic splines and Galerkin with linear triangular as well as quadratic quadrilateral isoparametric elements. The linearized collocation and Galerkin equations are solved by various direct methods available in the ELLPACK system. A comparative study of the above equation solvers is presented for different domain geometries and compilers. The evaluation of software for the general mildly nonlinear elliptic equations is performed over 36 instances from a population of 16 parametrized problems with ‘real world’ and ‘mathematical’ behaviour. The performance data suggests that collocation is an effective method for such general problems, while Galerkin with quadratic quadrilateral isoparametric elements is uniformly superior to the one with linear elements. 相似文献
147.
148.
Recent trends toward off-line printing have served to encourage serious development of off-line non-impact computer printer systems. For such systems, the combination of electrophotography and computer output printing is a natural candidate, not only because of the advantages which can be realized in the areas of flexibility, image quality, and speed, but also because of various other enhancement features which can be implemented. 相似文献
149.
Concerned with interactions between adult male and infant nonhuman primates and includes both field and laboratory data. Potential experimental factors involved in paternalistic behavior are listed and a few of these factors are shown to be of measurable importance in the development of paternal-like behaviors. These paternal-like behaviors, in turn, are seen as important in the behavioral development of the infant in natural and seminatural groups. (81 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
150.
This survey considers the use of ion-induced X-rays for elemental analysis of solids. The current state of the theory for both protons and heavy ion projectiles is discussed. In particular, the use of correlation diagrams is described, and examples are given to illustrate consequent applications. Selected practical applications are presented in some detail to elucidate the advantages of the technique, and also to point out some potential complications. 相似文献