Papers by Keyword: Stress Response

Abstract: The Haokou power station is located in the south of Wu Long in chongqing, which is a medium-sized hydropower project given priority to electricity. The Dam located in south bank of Wujiang river downstream of Furong river has the catchment area of 7400 km², total capacity of 94.12 million m³, installed capacity of 125 MW power . After the excavation of the main building, trailing edge to form 30 m high rock slope is tangential. Slope rock mass is given priority to with weakly weathered shale, mudstone, shallow accumulation horizon, thickness is about 0.5 m to 6.0 m. In analysis of slope stability, the FLAC 3d and the strength subtraction method was used. Considering of gravity, the shore web of pressure, water pressure and reinforcement bolt load combination, the stress response, displacement response, plastic zone as well as the safety factor of slope was analyzed. The calculation results show that the slope is stable.

Abstract: The activity response of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), ATP enzyme activities of Escherichia coli Q8, Bacillus subtilis L11, and Bacillus cereus OL-1 following exposure to 1,2-dichlorobenzene (1,2-DCB) was investigated. The bacterial strains were treated with the different concentrations of 1,2-DCB. Results obtained indicated that SOD and CAT activities in the tested bacteria increased significantly in a concentration-dependent manner after different concentrations of 1,2-DCB were applied. The activity of SOD in B. subtilis was stimulated and reached the highest level after treatment with 10 mg/L 1,2-DCB for 3 h. For B.cereus OL-1, there was another stimulation of SOD activity after 1,2-DCB application for about 5 h The stimulation by 1,2-DCB showed a relative lag for E. coli. 1,2-DCB had an evident influence on ATPase activity in the three bacteria within a relatively short period. 1,2-DCB would have caused a certain oxidative stress on the three bacteria which may not only elevate SOD and CAT activities but also generate new SOD isozymes to antagonize oxidative stress. All indirectly reflect the existence of poisonous and harmful material in the environment , and can indicate the influence of pollution sensitivily. Therefore SOD, CAT and ATP enzyme activity in microbial body can be regarded as a molecular index of polluting ,which is feasible.

Abstract: In recent years, the phenomenon of vehicle overload in highway transportation is more and more serious. The three-dimensional dynamic FEM was adopted and a three-dimensional simulative model for asphalt pavement with subgrade based on cross-anisotropy under moving load was established by the large-scale finite element analysis software ABAQUS. The response of the stress in the pavement structure was got by using ABAQUS/Standard code. During deceleration, The simulation analysis results under the rated load were compared with those under the different overload ratio. The results show that, under moving load, the surface course of pavement is mainly in three dimension compressive stress state. The horizontal load caused by deceleration has a remarkable effect on the longitudinal stress and the horizontal shearing stress. The stress of the pavement structure under overload is much greater than that caused by the rated load. And the greater the overload ratio, the greater the deviation between them.

Abstract: Nurses in Department of Emergency Medicine face the emergency of special populations; they live in special circumstances and shoulder a special mission, under the dual stress of internal and external environment source. However, whether the stressors cause stress to nurses is depending on the individual needs of the environment and the results interacting with their own resources assessment, if the assessment that the stress source exceeds the individual's response resources, the stress will be generated, which threats to the physical and mental health. This article pointed out that the stress of nurses in Department of Emergency Medicine is mainly from the patient care and nursing, most nurses are in moderate stress levels, nurses mainly use problem-directed response method, rather than emotion-directed response method. The problem-directed response method is significant negative correlation to the stress and emotion-directed response method is significant positive correlation.

Abstract: Oil pollution is seriously harmful to soil environment and human health. In order to verify the physiological and biochemical response of phytoremediation to oil-contaminated soil and test the relationship between the soil activity and the rate of oil degradation, in the present study, alfalfa, ryegrass, marigold and cosmos are used as the test plants. Through observing the morphological differences, such as germination rate, seedling height and root length, of four plant species under different concentrations of oil-contaminated soil, and measuring the physiological and biochemical indexes, which including MDA, soluble sugars, free proline, soluble protein and chlorophyll etc, and the change of oil degradation rate during the growth process of plant, results proved that plants could improve self-protection capabilities to resist the oil pollution by accumulating osmoregulation substances when they were subject to oil-contaminated stress. By analyzing the changes of polyphenol oxidase, it indicated that the plants can regulate enzyme activity in the oil-contaminated soil, and enhanced it. Comprehensive comparison of the above indexes, we draw a conclusion that alfalfa is an ideal species to repair the oil-contaminated soiland Marigold is the second candidate. In general, our work will lay the theoretic basis for phytoremediation technology research.

Abstract: The Escondida mine, located in northern Chile, is the largest copper producing mine in the world. It has an abundant low-grade (ca. 0.5% Cu) sulfide copper ore reservoir, which is processed in large heap bioreactors at the mine. To understand better how microorganisms adapt to heap leaching environments, we have isolated and identified acidophiles from pregnant leach solution (PLS) from the heaps. Six bacteria and one archaeon were isolated directly on solid overlay media, and identified by phylogenetic analyses of their 16S rRNA genes as strains of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferriphilum, Acidiphilium cryptum and Ferroplasma acidiphilum. The sequences of the 16S rRNA genes from isolated strains showed high similarity with those detected previously by culture-independent analyses performed on samples from a pilot plant for this process. Of the three known species of Leptospirillum, only L. ferriphilum has been detected in Escondida PLS. Tolerance of the Escondida isolate (coded IESL-25) to copper and some other transition metals such as zinc, nickel and silver was compared with several other strains of both L. ferriphilum and Leptospirillum ferrooxidans. It was noted that all L. ferriphilum strains (including IESL-25) displayed far greater tolerance to both copper and silver than strains of L. ferrooxidans, though tolerance to zinc and nickel was similar among isolates of both species. Micro-representational-difference analysis (MRDA) was used to study the genetic response of L. ferriphilum IESL-25 to high copper concentration. Gene sequences obtained by MRDA were analyzed using available genomic information for L. ferriphilum and one copper-induced gene identified appears to be involved in lipopolysaccharide biosynthesis.