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An electrically conductive plastic material was obtained by the polymerization of pyrrole on insulating polymeric materials
and nylon cloth impregnated with the oxidant by vapour phase technique, resulting in a uniform, smooth and adherent coating
of conducting polymer having a surface resistance ranging from 200 Ω/□ to 20 kΩ/□, which makes it suitable for applications
as an antistatic material. 相似文献
13.
PB DePetrillo 《Canadian Metallurgical Quarterly》1997,68(5):1863-1869
Calcium-activated neutral protease activity was determined in PC12 cells exposed to ethanol for 96 h using a fluorescence-based assay with N-succinyl-Leu-Tyr 7-amido-4-methylcoumarin as the substrate. Stimulated activity was measured at high (1,400 microM) or low (140 microM) Ca2+ concentrations in the presence of 20 microM ionomycin. Kinetic parameters were derived by fitting a model relating fluorescence intensity to time: F(t) = F(final)*(1 - e(-k(obs)t). Cell extracts were subjected to nondenaturing gel electrophoresis and casein zymography with quantification of the activity of the two calpain isoforms. Exposure to ethanol significantly decreased whole cell calpain activity measured by k(obs) beginning at 20 mM, to 27.8% of control at 1,400 microM Ca2+ and 29.2% of control at 140 microM Ca2+ in the presence of 20 microM ionomycin. No changes in mu-calpain or m-calpain activities were found in cell extracts from cells exposed to 20 mM ethanol, whereas at 40 and 80 mM ethanol, significant decreases in both mu-calpain and m-calpain activities were discovered. 相似文献
14.
Aortic valve endocarditis commonly leads to the formation of a root abscess, but fistulae are uncommon. The echocardiographic findings in a patient with Streptococcus viridans endocarditis of a prosthetic aortic valve associated with a fistula between the aorta and the left atrium are presented. The diagnosis was made by transthoracic echocardiography, although the transesophageal study gave higher resolution views and allowed a more confident exclusion of mitral valve involvement. 相似文献
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We have analyzed X-chromosome inactivation patterns in lymphocytes of 264 females from 38 families not known to have any genetic disease. Quantitative measures of X-inactivation showed strong sister-sister correlation in the degree of departure from equal numbers of cells having each X chromosome active, suggesting heritability of this phenotype. Strong sister-sister correlation was also observed for the fraction of cells having the same parent's X chromosome active, consistent with the possibility that this trait might be controlled by a cis-acting, X-linked gene. We used a sib-pair approach to determine whether X-inactivation phenotype was linked to loci in any region of the X chromosome. Both quantitative and discrete measures of X-inactivation phenotype showed evidence of linkage to markers in the region of the X inactivation center (XIC). The quantitative measure of X-inactivation phenotype used in our study also showed linkage to loci at Xq25-q26. This study provides the first evidence for X-linked inheritance of X chromosome inactivation phenotype derived from linkage analysis in phenotypically normal human families. 相似文献
17.
We review the localization problem in two dimensions for interacting bosons in a random potential. This problem is intimately related to the study of
4
He adsorbed in porous media, Josephson junction arrays, disordered superconducting films and vortex glasses. Using path integral Monte Carlo techniques, we find a superfluid, a localized or Bose glass insulator with gapless excitations, and (at commensurate densities) a Mott insulator with a finite gap to excitations. 相似文献
18.
In recent years, active learning has emerged as a powerful tool in building robust systems for object detection using computer vision. Indeed, active learning approaches to on-road vehicle detection have achieved impressive results. While active learning approaches for object detection have been explored and presented in the literature, few studies have been performed to comparatively assess costs and merits. In this study, we provide a cost-sensitive analysis of three popular active learning methods for on-road vehicle detection. The generality of active learning findings is demonstrated via learning experiments performed with detectors based on histogram of oriented gradient features and SVM classification (HOG–SVM), and Haar-like features and Adaboost classification (Haar–Adaboost). Experimental evaluation has been performed on static images and real-world on-road vehicle datasets. Learning approaches are assessed in terms of the time spent annotating, data required, recall, and precision. 相似文献
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The dc photocurrents generated by steady-state moving space-charge fields inside photoconductive semiconductors containing deep level donors and traps can be used to determine the relative frequency differences between the two interfering optical fields that establish the space-charge fields. A simple laser velocimeter that uses a semi-insulating GaAs:Cr sample to detect the Doppler frequency shift between two laser beams is demonstrated. 相似文献