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11.
To investigate the effects of hydration status on oxidative DNA damage and exercise performance, 10 subjects ran on a treadmill until exhaustion at 80% VO2max during four different trials [control (C), 3% dehydration (D), 3% dehydration + water (W) or 3% dehydration + sports drink (S)]. Dehydration significantly decreased exercise time to exhaustion (D < C and S). Plasma MDA levels were significantly higher at pre-exercise in D than C. Plasma TAS was significantly lower at pre-exercise in C and S than in D, and was significantly lower in S than D at 60 min of recovery. Dehydration significantly increased oxidative DNA damage during exercise, but fluid replacement with water or sports drink alleviated it equally. These results suggest that (1) dehydration impairs exercise performance and increases DNA damage during exercise to exhaustion; and (2) fluid replacement prolongs exercise endurance and attenuates DNA damage.  相似文献   
12.
The purpose of this review is to provide an overview of the effects of adenovirus and influenza virus infections on obesity in various experimental models. We reviewed studies that were conducted within the past 10 years and were related to virus infection and obesity prevalence. Here, we discuss a different causal relationship between adenovirus and influenza infections with obesity. Adenovirus infection can cause obesity, whereas obesity can be a risk factor for increasing influenza virus infection and increases the risk of morbidity and mortality. The prevalence of obesity due to adenovirus infections may be due to an increase in glucose uptake and reduction in lipolysis caused by an increase in corticosterone secretion. Adenovirus infections may lead to increases in appetite by decreasing norepinephrine and leptin levels and also cause immune dysfunction. The relationship between obesity and influenza virus infection could be summarized by the following features: decreases in memory T-cell functionality and interferon (IFN)-α, IFN-β, and IFN-γ mRNA expression, increases in viral titer and infiltration, and impaired dendritic cell function in obese individuals. Moreover, leptin resistance may play an important role in increasing influenza virus infections in obese individuals. In conclusion, prevention of adenovirus infections could be a good approach for reducing obesity prevalence, and prevention of obesity could reduce influenza virus infections from the point of view of viral infections and obesity.  相似文献   
13.
A study of the component synthesis method (CSM) for analyzing the normal mode dynamics of macromolecules is reported. The procedure involves a reduction of the dimensions of the normal mode problems for large molecular systems and the accurate extraction of the low-frequency modes. A macromolecule is divided into small components based on a hierarchical clustering of the residues in the structure. Interactions between coupled components are treated by the method of static correlation. The normal modes of the components are obtained first, and a fraction of the low-frequency normal modes of the components under mutual correlations are then used as a reduced basis for solving for the normal modes of the whole molecule. Multiple components are introduced for large macromolecules so that the dimensions of the eigenvalue problems at the component level are small. The method is applied to the protein crambin. In test calculations in which the dimensions of the eigenvalue equations are reduced to 1/6 of their natural size, the errors in the normal mode frequencies calculated by the CSM procedure are only about 1–2% when compared with the exact values. The rms fluctuations of all atoms in crambin calculated by the CSM procedure are basically identical to the exact results. The CSM procedure is shown to be accurate for calculating the normal modes of large macromolecules with a significant reduction of the size of the problem. © 1994 John Wiley & Sons, Inc.  相似文献   
14.
The chemiluminescence (CL) of bis(2,4,6‐trichlorophyenyl) oxalate with hydrogen peroxide in the present of cationic surfactant and gold nanoparticles was studied. The CL emission was obviously enhanced in the presence of surfactant at a suitable concentration, with a synergetic catalysis effect exhibited. Different sizes of gold nanoparticles (15 and 50 nm) showed different effects on CL intensity. Mechanisms of the CL reaction and sensitization effect are discussed. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
15.
We have recently isolated human and rat cDNAs (designated FER and flk, respectively) which encode nonreceptor protein-tyrosine kinases which are very similar to one another and related in sequence and domain structure to the c-fps/fes gene product. We show that FER and flk are human and rat counterparts of an evolutionarily conserved gene, hereafter termed FER regardless of species. The human and rat FER genes encode a widely expressed 94-kilodalton protein-tyrosine kinase which is antigenically related to the fps/fes protein-tyrosine kinase. The structural and antigenic similarities between the FER and fps/fes proteins suggest that they are members of a new family of nonreceptor protein-tyrosine kinases.  相似文献   
16.
The nucleus of a blastula cell from Tilapia (Oreochromis nilotica, family Cichlidae, order Perciformes) was transplanted into an enucleated egg of Loach (Paramisgurnus dabryanus, family Cobitidae, order Cypriniformes). From among 3747 nucleo-cytoplasmic hybrid (NCH) eggs two NCH larval fish (0.05%) were obtained; one died on the 6th day and the other died on the 12th day after the operation. Morphological examinations showed that both NCH larval fish had developed normally with an opened mouth except they could not take food after complete utilization of their egg yolk on the 5th day of development. The possible mechanisms for obtaining such inter-order NCH larval fish are discussed. This is the first report indicating that inter-order NCH larval fish can be obtained in spite of their evolutionary divergence.  相似文献   
17.
Raw leachate was treated using a two-stage upflow anaerobic filter process. Leachate from a solid waste landfill site, which received both municipal and industrial wastes, contained high organic matter (17-21 g/L COD, 13-14 g/L BOD, and 3.5-4.6 g/L volatile acids), and low metal (Zn and Fe) concentrations. Depending on sampling time, leachate composition and characteristics varied considerably. At an organic loading up to 4 g COD/day(2) media area, the BOD and COD removal percentages were 98 and 91%, respectively. The biofilters were also effective for metal removal. However, the filter effluent contained a high concentration of ammonia. System overloading was characterized by the accumulation of large quantities of volatile acids and by a now ratio of alkalinity/volatile acids, resulting in low COD removal and reduced gas production. Once the first filter was upset, the second stage could only partially respond to the volatile acids accumulated in the effluent of first filter.  相似文献   
18.
本文进一步研究了我国不同民族的正常个体以及β地中海贫血患者θ珠蛋白基因5′侧序列中的多态性HincⅡ位点及其遗传性质。在广西壮族正常个体和β地中海贫血纯合子中,该多态性位点的发生频率均为75%,与正常汉族人测得值相近。家系分析资料表明,该多态性位点完全按照孟德尔规律进行遗传。  相似文献   
19.
D Schubert  L W Jin  T Saitoh  G Cole 《Neuron》1989,3(6):689-694
The regulation and function of two forms of the amyloid beta protein precursor (ABPP) that are released into the growth-conditioned medium of the PC12 nerve cell line were examined. Nerve growth factor increases the release of the form of ABPP without the protease-inhibitor domain relative to the protein containing the protease inhibitor and increases the overall rate of ABPP secretion 2-fold. In contrast, fibroblast growth factor increases the rate of ABPP secretion approximately 7-fold. Both forms of the secreted ABPP molecule are, in turn, able to stimulate adhesion of PC12 cells to substrata to which they are adsorbed about 10-fold more efficiently on a molar basis than Iaminin.  相似文献   
20.
植物群落演替与土壤发展之间的关系   总被引:46,自引:0,他引:46  
本文运用植物群落中植物优势种的重要值与相对应子群落的土壤特征值直接相关联的分析方法,对湖北宜昌大老岭的桦(Betula)、栎(Quercus)、栗(Castanea)七个群落类型的三个演替途径的土壤动态进行分析,结果表明:在植物群落的演替过程中,土壤中的Ca、pH值减少;离子代换量增加;Na、Mg、NH_4+-N、速效P、速效K、有机质的含量是随着物种的变化而呈不同的趋势。因此,植物群落的演替是生态系统的动态过程。  相似文献   
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