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231.
The temperature dependence of the dielectric characteristics of metal-containing polymer films obtained using electrochemical polymerization of a Ni(II) complex monomer [NiSalen] have been studied in a temperature interval from 290 to 370 K. The low-frequency polarization characteristics of poly[NiSalen] film samples exhibit a temperature hysteresis. It is suggested that the observed features of a relaxation type are related to reversible transformations of the redox form of the polymer. 相似文献
232.
Human larynx carcinoma cells (HEp2) were sensitized with different concentrations of Hematoporphyrin and irradiated with a He-Ne laser at different fluences. The degree of PDT-effects were estimated by two parameters: a) macromolecular synthesis and b) observations using electron microscopy. All experiments were evaluated after 68 hr at 37 degrees C. The results showed that PDT exposure of HEp2 cells is characterized by: 1) inhibition of macromolecular synthesis and 2) different cellular and subcellular lesions. Summing up, these studies indicate the existence of a strong correlation between different PDT exposures and the degree of biochemical and ultrastructural changes in human larynx carcinoma cells in vitro. 相似文献
233.
234.
Conclusions We have developed a computational-experimental model for determining the parameters of the corrosion process under the conditions
of cathode protection, which allowed us to establish that the cathode protection substantially reduces the losses to corrosion
in carburized, nitrided, diffusion calorized, and chromized coatings.
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 34–36, June, 2000. 相似文献
235.
MA Baz VF Tapson VL Roggli P Van Trigt CA Piantadosi 《Canadian Metallurgical Quarterly》1996,153(2):742-746
The lower respiratory tract is protected against reactive oxygen species (ROS) by a complex antioxidant system. In the epithelial lining fluid (ELF), glutathione (L-alpha-glutamyl-L-cysteinylglycine, GSH) is essential for adequate protection of pneumocytes from potential toxicity mediated by extracellular hydrogen peroxide (H2O2). We assessed the concentration of total GSH in bronchoalveolar lavage fluid (BALF) in lung allograft patients in the absence and presence of acute rejection. Bronchoalveolar lavage (BAL) and biopsies were performed concurrently on 36 occasions in 17 patients who had undergone lung transplantation. BALF samples were divided into two groups on the basis of presence or absence of acute lung rejection on transbronchial biopsy. Seven BALF samples were obtained from control subjects for comparison. The BALF data demonstrated significantly lymphocyte recruitment and evidence of lung injury during acute rejection episodes. Transplant allografts without rejection showed significant depletion of total GSH in the ELF as compared with that of normal volunteers (94.0 +/- 9.7 microM versus 302.6 +/- 40.8 microM, p < 0.01). Transplant allografts with acute rejection had a slightly higher GSH concentration in their ELF (179.8 +/- 34.7), but this was still lower than control values. The deficiency of total GSH in the alveolar fluid may predispose lung allografts to extracellular H2O2-mediated toxicity. 相似文献
236.
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238.
VF Van Tendeloo HW Snoeck F Lardon GL Vanham G Nijs M Lenjou L Hendriks C Van Broeckhoven A Moulijn I Rodrigus P Verdonk DR Van Bockstaele ZN Berneman 《Canadian Metallurgical Quarterly》1998,5(5):700-707
Human dendritic cells (DC) are highly professional antigen presenting cells for the priming of naive cytotoxic T cells. Gene transfer in DC would be a useful strategy to load DC with relevant de novo synthesized antigens for immunotherapeutical purposes. As a first step towards a DC-based gene therapy, we examined the efficiency of nonviral transfection in different types of cultured human dendritic cells with a humanized red-shifted green fluorescent protein reporter gene. Plasmid DNA transfection by electroporation or lipofection was used to transfect CD34+ progenitor cell-derived DC (PC-DC) and Langerhans' cells (PC-LC), as well as monocyte-derived DC (Mo-DC). While lipofection was unsuccessful in all types of DC, we obtained high-efficiency gene transfer by electroporation in PC-LC (16%) and PC-DC (12%). In contrast, electroporation was strikingly less efficient in Mo-DC (< or = 2%). The potent allostimulatory capacity of DC was still retained in electroporated PC-DC and PC-LC. In conclusion, electroporation of antigen expressing plasmid DNA is an efficient tool for nonviral gene transfer in PC-DC and PC-LC, but not in Mo-DC and could be useful for the development of DC-based tumor immunotherapy. 相似文献
239.
ML Sartakova VI Konenkov VF Prokof'ev EL Gel'fgat AM Lamazhaa LG Dongak SI Kara-Mongush 《Canadian Metallurgical Quarterly》1998,34(8):1127-1133
The results of DNA typing of the HLA-DPB1 gene among Tuvinians are described. The allele 0201 was found to be the most frequent (26.66%); then, in order of decreasing frequency, followed the alleles 0401 (26.42%), 0402 (13.99%), 0301 (8.55%), 0501 (7.77%), 0901 (5.16%), and 1301 (2.07%). The frequency of the allele 0501 in Tuvinians was significantly lower than that in the published data on allele distributions characteristic of two other Mongoloid populations, the Manchu and Japanese. The results of the serological typing of the loci HLA-A, -B, and -Cw of class I in the Tuva population were compared to the corresponding published data on ten Mongoloid populations of Central and Eastern Asia: Uigurs, Kazakhs, Mongols, Manchu, Tibetans, the Chinese of the northern and southern regions of China, Thais (inhabitants of Northwestern Indochina), Koreans, and Japanese. In Tuvinians, the most frequent antigens were HLA-A2, -A9, -B0, -B35, -B17, -Cw4, and -DR5. In the inhabitants of Tuva, the frequency of the antigens HLA-A1, -A9, -B17, -Cw2, and -Cw4 was significantly higher than in other Mongoloids, while that of the antigens HLA-A26 and -B22 was lower. This difference was greatest in the case of antigen HLA-B40: it a frequency of 43.4% was detected in it, while in individuals of Mongolian origin, the frequency of this antigen did not exceed 22.5%. Indices of genetic similarity (IGSs), calculated from the gene frequencies of the loci HLA-A, -B, and -Cw, suggested that the Tuvinians were most closely related to Kazakhs (IGS = 0.73), and least related to the Japanese and Uigurs (IGS = 0.66). Our data suggest that Tuvinians significantly differ from the compared populations of Central and Eastern Asia. 相似文献
240.
S Ruffert C Lambert H Peter VF Wendisch R Kr?mer 《Canadian Metallurgical Quarterly》1997,247(2):572-580
Bacteria respond to hypoosmotic stress by releasing low-molecular-mass solutes in order to maintain constant turgor pressure. We have studied the function of osmoregulated channel(s) in Corynebacterium glutamicum, which are responsible for efflux of various solutes upon sudden decrease in osmotic pressure. The channels preferentially mediated efflux of compatible solutes such as glycine betaine and proline. The release of molecules of similar size, e.g. glutamate or lysine, was restricted, ATP was completely retained even after severe osmotic shock. The cells maintained high cytoplasmic K+ and Na+ concentrations under hypoosmotic shock. Several results suggest that the solute efflux is mediated by a channel and not by a carrier, e.g. by reversal of the glycine betaine uptake systems of C. glutamicum: the release of glycine betaine and proline was extremely fast reaching an efflux rate of 6000 micromol x min(-1) x g dm(-1) or higher; the efflux was not significantly influenced by addition of external transport substrate, e.g. glycine betaine; in spite of an extremely high chemical gradient, no significant efflux under isoosmolar conditions was observed; efflux of solutes was unchanged after full uncoupling of membrane energetics by carbonylcyanide m-chlorophenylhydrazone (CCCP). These results indicate the presence of an osmoregulated channel in C. glutamicum similar to the mechanosensitive channel(s) of Escherichia coli. The activity of the channel did not depend on the growth conditions, but we observed a tight regulation on the level of activity, i.e. the mechanosensitive channel behaved as a perfect osmometer. By monitoring release of glycine betaine under slow and continuous decrease of the external osmolality, we observed continous efflux whithout a stepwise release of solutes. This resulted in a significant steady-state decrease of the membrane potential. 相似文献