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1.
GN Mozhokina GB Sokolova OV Makarova LP Mikha?lova 《Canadian Metallurgical Quarterly》1996,41(7-8):31-33
The effect of lomefloxacin was studied on mice with experimental infection due to Mycobacterium tuberculosis. The antibiotic was administered in doses of 100 and 200 mg/kg. It was shown that the use of lomefloxacin for a month provided a lower death rate of the animals with progressing acute generalized tuberculosis, a lower level of the lesions in the internal organs and a lower number of the Mycobacterium isolates from them. The efficacy of the treatment depended on the drug dose. When lomefloxacin was used in a dose of 200 mg/kg, the survival rate was much higher and the number of the epithelial unicellular granulomas in the tissue of the lung and spleen was markedly decreased while with the lower dose the indices did not differ from those in the control. 相似文献
2.
Ivo M. Babuka Rodolfo Rodriguez 《International journal for numerical methods in engineering》1993,36(4):539-567
This paper addresses the problem of assessing the quality of an a posteriori error estimate of a finite element solution. An error estimate based on local L2-projections is analysed in the case of translation-invariant meshes. It is shown that for general meshes this technique does not lead to an asymptotically exact estimator. The problem is analysed in detail in the one-dimensional setting. It is shown that an asymptotically exact estimator is not the optimal one when the solution is not sufficiently smooth. An optimal estimator for adaptively constructed meshes is given. Finally, a general mathematical framework for the quality assessment of estimators is introduced. 相似文献
3.
Rat liver microsomes and, to a lesser extent, nuclei were previously shown to produce reactive oxygen species at elevated rates after chronic ethanol treatment. The ability of intact rat liver mitochondria to interact with iron and either NADH or NADPH, and the effects of ethanol treatment, on production of reactive oxygen intermediates was determined. In the presence of ferric-ATP, NADH or NADPH catalyzed mitochondrial lipid peroxidation. Rates were elevated two- to threefold with mitochondria from ethanol-fed rats with both reductants. Mitochondrial lipid peroxidation was insensitive to superoxide dismutase, catalase, or hydroxyl radical scavengers but was sensitive to GSH and anti-oxidants such as trolox. Mitochondrial generation of hydroxyl radical-like species (assayed by oxidation of chemical scavengers) was increased after chronic ethanol treatment, as was H2O2 production. Modifiers of mitochondrial metabolism such as rotenone, cyanide, or an uncoupling agent, had no effect on mitochondrial production of reactive oxygen intermediates. The membrane-impermeable thiol reagent, p-chloromercuribenzoate, was complete inhibitory with both mitochondrial preparations. The activity of the rotenone-insensitive NADH-cytochrome c reductase, an enzyme of the outer mitochondrial membrane, was increased 40 to 60% by the ethanol treatment. These results suggest that NADH acting via the outer membrane NADH reductase can catalyze an iron-dependent production of oxygen radicals by rat liver mitochondria. The outer mitochondrial membrane fraction, prepared by digitonin fractionation, displayed increased rotenone-insensitive NADH-cytochrome c reductase activity after ethanol treatment and was more reactive in catalyzing scission of pBR322 DNA from the supercoiled form to the open circular forms. Rates of oxygen radical production by mitochondria and the extent of increase produced by chronic ethanol treatment are similar to those previously found with microsomes when NADH is the cofactor. Oxidation of ethanol by alcohol dehydrogenase generates NADH, and NADH-dependent production of reactive oxygen species by various organelles is increased after chronic ethanol treatment. These acute metabolic interactions coupled to induction by chronic ethanol treatment may play an important role in the development of a state of oxidative stress in the liver by ethanol. 相似文献
4.
V. V. Ruzhyts’kyi H. D. Tolstoluts’ka S. O. Karpov I. E. Kopanets’ H. M. Malyk 《Materials Science》2007,43(5):735-741
By the methods of thermal-desorption spectrometry and nuclear reactions, we study the processes of trapping, thermal desorption,
and evolution of the profiles of distribution of deuterium ionically implanted with an energy of 12 keV into Kh18N10T steel
at room temperature. The evolution of the microstructure of steel under the conditions of irradiation of samples with D2+ ions up to doses of 1 · 1018 D/m2−2 · 1022 D/m2 is studied by the method of electron microscopy. The regularities of changes in the mechanical properties of steel after
irradiation are determined.
__________
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 5, pp. 117–121, September–October, 2007. 相似文献
5.
C. A. Duarte I. Babuka 《International journal for numerical methods in engineering》2002,55(12):1477-1492
This paper is aimed at presenting a simple yet effective procedure to implement a mesh‐independent p‐orthotropic enrichment in the generalized finite element method. The procedure is based on the observation that shape functions used in the GFEM can be constructed from polynomials defined in any co‐ordinate system regardless of the underlying mesh or type of element used. Numerical examples where the solution possesses boundary or internal layers are solved on coarse tetrahedral meshes with isotropic and the proposed p‐orthotropic enrichment. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
6.
VN Dobrovolsky OV Lagutin TV Vinogradova IS Frolova VP Kuznetsov OA Larionov 《Canadian Metallurgical Quarterly》1993,319(1-2):181-184
Transgenic mice carrying a hybrid gene consisting of ovine beta-lactoglobulin gene sequences and human gamma-interferon (hIFN-g) cDNA were produced. hIFN-g expression in the mammary gland of two lactating transgenic founder females was found. The concentration of active hIFN-g in the milk was estimated as being ca. 1800 IU/ml. The hIFN-g ability to express in the mammary gland was found in the progeny of transgenic founder male. 相似文献
7.
8.
In this paper we consider the p-ary transitive reduction (TR
p
) problem where p>0 is an integer; for p=2 this problem arises in inferring a sparsest possible (biological) signal transduction network consistent with a set of
experimental observations with a goal to minimize false positive inferences even if risking false negatives. Special cases
of TR
p
have been investigated before in different contexts; the best previous results are as follows:
In this paper, our contributions are as follows:
R. Albert’s research was partly supported by a Sloan Research Fellowship in Science and Technology.
B. DasGupta’s research was partly supported by NSF grants DBI-0543365, IIS-0612044 and IIS-0346973.
E. Sontag’s research was partly supported by NSF grants EIA 0205116 and DMS-0504557. 相似文献
(1) | The minimum equivalent digraph problem, that correspond to a special case of TR1 with no critical edges, is known to be MAX-SNP-hard, admits a polynomial time algorithm with an approximation ratio of 1.617+ε for any constant ε>0 (Chiu and Liu in Sci. Sin. 4:1396–1400, 1965) and can be solved in linear time for directed acyclic graphs (Aho et al. in SIAM J. Comput. 1(2):131–137, 1972). |
(2) | A 2-approximation algorithm exists for TR1 (Frederickson and JàJà in SIAM J. Comput. 10(2):270–283, 1981; Khuller et al. in 19th Annual ACM-SIAM Symposium on Discrete Algorithms, pp. 937–938, 1999). |
• | We observe that TR p , for any integer p>0, can be solved in linear time for directed acyclic graphs using the ideas in Aho et al. (SIAM J. Comput. 1(2):131–137, 1972). |
• | We provide a 1.78-approximation for TR1 that improves the 2-approximation mentioned in (2) above. |
• | We provide a 2+o(1)-approximation for TR p on general graphs for any fixed prime p>1. |
9.
OV Sivochalova 《Canadian Metallurgical Quarterly》1995,(9):1-4
Modern demographic situation stressed the problems of human reproductive health associated with industrial medical topics. The article suggests to regard a family (child and two parents) as a unit under study in industrial medicine. This methodic approach should work in scientific programs reviewing influence of industrial ecology and environmental factors on reproductivity. The authors suggest elaboration of universal strategy for ecologic and epidemiologic studies to form a scientific branch "Epidemiology of reproductive health" and to elaborate methods for better health management during the present demographic crisis. 相似文献
10.
NS Kislitsina BA Katsnel'son LI Privalova OV Driakhlova 《Canadian Metallurgical Quarterly》1995,(10):31-34
The authors proved that animals having higher natural antioxidant activity and lower intensity of lipid peroxidation are more resistant to fibrogenic effects of quartz. The peritoneal macrophages obtained from those animals show higher resistance to quartz exposure "in vitro". Parameters characterizing antioxidant system should be included into a group of indexes describing propensity to silicosis. 相似文献