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排序方式: 共有1177条查询结果,搜索用时 296 毫秒
971.
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973.
S Charrier J Chassagne H Curé JO Bay Y Communal G Portefaix JP Ferrière G Bétail R Plagne P Chollet 《Canadian Metallurgical Quarterly》1998,22(9):845-851
Fermentations of Streptomyces sp. E/784 produce low levels of the novel C-30 alkylthio-substituted ansamycin antibiotics naphthomycins J (9) and I (10), in addition to the more abundant C-30 hydroxylated analogues actamycin (1) and naphthomycin D (2) and C-30 chlorinated analogues naphthomycins H (3) and A (4). The addition of N-acetyl-L-cysteine to the fermentation medium substantially increases the production of the thionaphthomycins J and I at the expense of their chloro analogues H and A. Other thiols and thiol progenitors are similarly utilised, including N-acetyl-L-cysteine methyl ester which affords the known naphthomycin F (8) and its novel 2-demethyl homologue (7). The formation of thioansamycins from chloroansamycins and thiols in vivo is probably non-enzymic since similar conversions can be effected in vitro. 相似文献
974.
VV Kaliakin VS Sokolova VP Strel''tsov LK Bronskaia AT Sigaev AV Perfil''ev 《Canadian Metallurgical Quarterly》1998,2(4):33-38
Home care is replacing the traditional hospital stay for a variety of acute and chronic illnesses. The delivery of home antibiotic infusion therapy is an innovative treatment approach for stable term infants with suspected or confirmed infection. Neonates are a unique group of home i.v. therapy recipients, and programs specific to the needs of this population must be developed. This article describes one such program in detail. 相似文献
975.
Juan Gutiérrez Francesc J Ferri Jesús Malo 《IEEE transactions on image processing》2006,15(1):189-200
Image restoration requires some a priori knowledge of the solution. Some of the conventional regularization techniques are based on the estimation of the power spectrum density. Simple statistical models for spectral estimation just take into account second-order relations between the pixels of the image. However, natural images exhibit additional features, such as particular relationships between local Fourier or wavelet transform coefficients. Biological visual systems have evolved to capture these relations.We propose the use of this biological behavior to build regularization operators as an alternative to simple statistical models. The results suggest that if the penalty operator takes these additional features in natural images into account, it will be more robust and the choice of the regularization parameter is less critical. 相似文献
976.
CY Shen HS Lee LC Huang KS Tsai DS Chen AT Cheng 《Canadian Metallurgical Quarterly》1996,143(9):936-942
Viral hepatitis and alcoholism prevail in four major Taiwanese aboriginal groups. To study the relative importance of the acquisition of hepatitis B virus or hepatitis C virus infection and alcoholism to the presence of impaired liver function in these groups, the authors conducted a semistructured clinical interview for alcoholism and test for seromarkers for viral hepatitis among 993 cohort members enrolled in 1990-1992 in an ongoing prospective study (Taiwan Aboriginal Study Project). The subjects' blood specimens were tested for serum alanine aminotransferase/aspartate aminotransferase levels and for the presence of hepatitis B surface antigen and anti-hepatitis C virus antibody. The prevalence of a combination of an alanine aminotransferase level of > 35 IU/liter and an aspartate aminotransferase level of > 40 IU/liter, implying impaired liver function or advanced liver disease, was 4.3% overall. Univariate and multiple logistic regression analysis showed that, rather than chronic hepatitis B virus infection, hepatitis C virus infection and alcoholism were the two dominant risk factors that signalled the risk of liver damage among these Taiwanese aborigines. In addition, these two contributing factors were able to act synergistically to cause impaired liver function. 相似文献
977.
Giuseppe Ferri Vincenzo Stornelli Mauro Fragnoli 《Analog Integrated Circuits and Signal Processing》2006,48(3):247-250
In this paper a novel low voltage low power topology of second generation current conveyor (CCII) is presented. The internal
CCII stages have been designed to obtain, at X and Z nodes, reduced parasitic impedances, so improving CCII performance. As an application example, the here proposed CCII, designed
in standard CMOS technology (AMS 0.35 μm), has been used to design an integrated resistive sensor interface, showing the capability
of compensating the non idealities of passive and active components. Preliminary and post-layout simulations show an excellent
linearity for what concerns sensor sensitivity. 相似文献
978.
979.
980.
Advanced oxidation protein products as novel mediators of inflammation and monocyte activation in chronic renal failure 总被引:1,自引:0,他引:1
V Witko-Sarsat M Friedlander T Nguyen Khoa C Capeillère-Blandin AT Nguyen S Canteloup JM Dayer P Jungers T Drüeke B Descamps-Latscha 《Canadian Metallurgical Quarterly》1998,161(5):2524-2532
We previously demonstrated the presence of advanced oxidation protein products (AOPP), a novel marker of oxidative stress in the plasma of uremic patients receiving maintenance dialysis. The present study in a cohort of 162 uremic patients showed that plasma concentrations of AOPP increased with progression of chronic renal failure and were closely related to advanced glycation end products (AGE)-pentosidine (r = 0.52, p < 0.001), taken as a marker of AGE. In vivo, the relevance of AOPP and AGE-pentosidine in monocyte-mediated inflammatory syndrome associated with uremia was evidenced by close correlations between AOPP or AGE-pentosidine and monocyte activation markers, including neopterin, IL-1R antagonist, TNF-alpha, and TNF soluble receptors (TNF-sR55 and TNF-sR75). To determine the mechanisms by which AOPP and AGE could be directly involved in monocyte activation, AOPP-human serum albumin (HSA) and AGE-HSA were produced in vitro by treating HSA with oxidants or glucose, respectively. Spectroscopic analysis confirmed that AOPP-HSA contains carbonyls and dityrosine. Both AOPP-HSA and AGE-HSA, but not purified dityrosine, were capable of triggering the oxidative burst of human monocytes in cultures. The AOPP-HSA-induced respiratory burst was dependent on the chlorinated nature of the oxidant and on the molar ratio HSA/HOCI. Collectively, these data first demonstrate that AOPP act as a mediator of oxidative stress and monocyte respiratory burst, which points to monocytes as both target and actor in the immune dysregulation associated with chronic uremia. 相似文献