It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can norma...It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can normally be significantly accelerated by bacterial activity. However,this paper reports on the corrosion of highly active Mg interestingly inhibited by an algal-symbiotic bacterium Bacillus altitudinis. The corrosion of Mg in the presence of the bacterium drastically reduced by one order of magnitude after 14 days of immersion. This means that the algal-symbiotic bacterium widely available in natural ocean environments may be employed as a green and sustainable inhibitor in the marine industry. Based on electrochemical measurements, surface analyses and microbe experiments, a combined inhibition mechanism is proposed in the paper to interpret the interesting corrosion behavior of Mg.展开更多
This research investigated the outputting circulation current inhibition characteristic which are controlled by the instantaneous feedback voltage in inverter parallel driving of the mine hoist. We established a trans...This research investigated the outputting circulation current inhibition characteristic which are controlled by the instantaneous feedback voltage in inverter parallel driving of the mine hoist. We established a transfer function of the parallel inverters controlled by the close-loop adjustment of instantaneous voltage feedback. The influence of the parameters of the close-loop feedback circuit to the inhibition effects to the outputting circulation current is observed. After analyzing the circulating current inhibition characteristics, the proportion integration （PI） controller is introduced into the close-loop adjustment by instantaneous voltage feedback. The characteristics equation is gained to determine the PI parameters by drawing the Bode plots. The inhibition effects of the proposed controller are examined by the established simulation model of parallel inverter system. The harmonic distortion rate at the outputting voltage frequency value of 4, 10, 20, 41 and 50 Hz, are all lower than 2.32 % by the instantaneous outputting voltage feedback.展开更多
A new extracelluar polysaccharide （EPS） was isolated and purified from Antarctic bacterium S-15-13, identified as Pseudoalteromonas sp. After being separated and purified by DEAE-Sephadex A-50 ionexchange and Sephad...A new extracelluar polysaccharide （EPS） was isolated and purified from Antarctic bacterium S-15-13, identified as Pseudoalteromonas sp. After being separated and purified by DEAE-Sephadex A-50 ionexchange and Sephadex G-100 gel chromatography, two mains fractions （EPS I and EPS Ⅱ ） were ob-tained. EPS I was composed of mannose, glucose and galactose with a molecular weight of 23kDa and EPS Ⅱ was composed of mannose only with a molecular weight of 62kDa. The effect of the polysaccharide EPS I on the cellular immune response of mice was investigated. Results demonstrated that EPS I could markedly facilitate lymphocyte proliferation, and might be a strong immunomodulator.展开更多
Introduction: Nitrogen (N) fertilizer is the most widely used fertilizer (300 - 350 Kg/Ha) on the corn plant, mean while it has mobile character, so it becomes the lowest utilization (40% - 50%) compared to other nutr...Introduction: Nitrogen (N) fertilizer is the most widely used fertilizer (300 - 350 Kg/Ha) on the corn plant, mean while it has mobile character, so it becomes the lowest utilization (40% - 50%) compared to other nutrient elements. Aims: The aim of this research is to examine the effect of various qualities and dose of litter on the dynamics of N mineral soil and soil nitrification potential on maize cultivation system. Method: The treatment is set by Randomized Completely Block Design (RCBD). Four kinds of litter is chosen to represent the groups of low quality (Tectona grandis and Pterocarpus indicus) and the groups of high quality (Oryza sativa and Eupatorium inulifolium) are given on four doses: 4, 8, 12 and 16 mg/Ha. All treatments are fertilized with urea 150 kg/Ha. Variables measured include the soil concentration of NH4- and NO3-, potential nitrification conducted in 2, 4, 6, 8 and 10 weeks after planting the corn. Result: The research shows that the addition of low-quality litter is influenced very significantly by release of NH4-, formation of NO3- and potential nitrification of soil. Others results show that the content of litter (lignin, polyphenol and C/N ratio) has the most powerful influence as regulator of NH4- released (p NO3- (p < 0.01) and potential nitrification of soil (p < 0.01) rather than the content of lignin, polyphenol and C/N ratio of litter separately. Conclusion: The conclusion of this research is that the management of litter quality input can be applied in the field to regulate the process of nitrification in soil and potential to increase N used efficiency of corn plant.展开更多
Enriched by the-medium containingchitin and cell wall of Phizoctoniasolani AG-1,a bacterium X2-23 withhigher chitinase activity was isolatedfrom 166 chitinase-producing bacteria.It could distinctly inhibit the fungi
The kinetics of asymmetric production of R-（-）-mandelic acid （R-MA） from phenylglyoxylic acid （PGA） catalyzed by Saccharomyces cerevisiae sp. strain FD11b was studied by fed-batch cultures. The concentrations of...The kinetics of asymmetric production of R-（-）-mandelic acid （R-MA） from phenylglyoxylic acid （PGA） catalyzed by Saccharomyces cerevisiae sp. strain FD11b was studied by fed-batch cultures. The concentrations of glucose and PGA were controlled respectively with a dual feeding system. When the electron donor glucose was supplied at the rate of 0.0833mmol·gdw^-1·h^-1, the specific production rate （qp） and the enantiomeric excess of R-MA reached the maximum 0.353mmol·gdw^-1·h^-1 and 97.1%, respectively. The apparent reduction activity of yeast FD 11 b was obviously affected by both substrate PGA and product MA. The qp value reached the maximum 0.36-0.38mmol·gdw^-1·h^-1 when the PGA concentration was controlled between 25 and 35mmol·L^-1. The obvious substrate inhibition of bioconversion was observed at the PGA concentrations higher than 40mmol·L^-1. The accumulation of product MA also caused a severe feed-back inhibition for its production when the product concentration was above 60mmol·L^-1. The kinetic model with the inhibition effect of both substrate and product was simulated by a computer-based least-square arithrnatic. The established kinetic model was in good agreement with the experimental data.展开更多
The authors synthesized a series of novel 5-heterocycloxy-3-substituted-1-（3-trifluoromethyl）phenyl-1H- pyrazole derivatives. Herbicidal activities of the two intermediate compounds and thirteen target compounds wer...The authors synthesized a series of novel 5-heterocycloxy-3-substituted-1-（3-trifluoromethyl）phenyl-1H- pyrazole derivatives. Herbicidal activities of the two intermediate compounds and thirteen target compounds were evaluated via Brassica napus and Echinochloa crusgalli（L.） Beauv tests. Bioassay results show that some of the compounds exhibit better inhibiting activities against Brassica napus and some of the compounds exhibit bleaching activities against Echinochloa crusgalli（L.） Beauv at 100 μg/mL.展开更多
Urokinase-type plasminogen activator （uPA） is a trypsin-like serine protease and plays a key role in several biological processes, including tissue remodeling, cell migration, and matrix degradation. The inhibitors ...Urokinase-type plasminogen activator （uPA） is a trypsin-like serine protease and plays a key role in several biological processes, including tissue remodeling, cell migration, and matrix degradation. The inhibitors of uPA have been shown to prevent the spread of metastasis and tumor growth, and accordingly uPA is widely recognized as a target for the treatment of cancer. In this work, we report the crystal structures of the complexes of uPA with its inhibitors： 4- （aminomethyl）-benzoic acid （AMBA） and 4-（aminomethyl-phenyl）-methanol （AMPM）, both at a resolution of 2.35 А. The inhibitory constants of these two inhibitors were measured by a chromogenic competitive assay, and it was found that AMBA is a better inhibitor for uPA （Ki = 2.68 mM） than AMPM （Ki = 13.99 mM）. The structural study shows that the binding mode of inhibitor AMBA on uPA is similar to that of AMPM on uPA, both docked into the active site S1 pocket of uPA. Structural details of these complexes are provided to explain the difference of inhibitory constants.展开更多
基金the National Natural Science Foundation of China (Nos.51731008,52250710159,51671163,51901198)the National Key Research and Development Program of China (No.2017YFB0702100)。
文摘It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can normally be significantly accelerated by bacterial activity. However,this paper reports on the corrosion of highly active Mg interestingly inhibited by an algal-symbiotic bacterium Bacillus altitudinis. The corrosion of Mg in the presence of the bacterium drastically reduced by one order of magnitude after 14 days of immersion. This means that the algal-symbiotic bacterium widely available in natural ocean environments may be employed as a green and sustainable inhibitor in the marine industry. Based on electrochemical measurements, surface analyses and microbe experiments, a combined inhibition mechanism is proposed in the paper to interpret the interesting corrosion behavior of Mg.
文摘This research investigated the outputting circulation current inhibition characteristic which are controlled by the instantaneous feedback voltage in inverter parallel driving of the mine hoist. We established a transfer function of the parallel inverters controlled by the close-loop adjustment of instantaneous voltage feedback. The influence of the parameters of the close-loop feedback circuit to the inhibition effects to the outputting circulation current is observed. After analyzing the circulating current inhibition characteristics, the proportion integration （PI） controller is introduced into the close-loop adjustment by instantaneous voltage feedback. The characteristics equation is gained to determine the PI parameters by drawing the Bode plots. The inhibition effects of the proposed controller are examined by the established simulation model of parallel inverter system. The harmonic distortion rate at the outputting voltage frequency value of 4, 10, 20, 41 and 50 Hz, are all lower than 2.32 % by the instantaneous outputting voltage feedback.
文摘A new extracelluar polysaccharide （EPS） was isolated and purified from Antarctic bacterium S-15-13, identified as Pseudoalteromonas sp. After being separated and purified by DEAE-Sephadex A-50 ionexchange and Sephadex G-100 gel chromatography, two mains fractions （EPS I and EPS Ⅱ ） were ob-tained. EPS I was composed of mannose, glucose and galactose with a molecular weight of 23kDa and EPS Ⅱ was composed of mannose only with a molecular weight of 62kDa. The effect of the polysaccharide EPS I on the cellular immune response of mice was investigated. Results demonstrated that EPS I could markedly facilitate lymphocyte proliferation, and might be a strong immunomodulator.
文摘Introduction: Nitrogen (N) fertilizer is the most widely used fertilizer (300 - 350 Kg/Ha) on the corn plant, mean while it has mobile character, so it becomes the lowest utilization (40% - 50%) compared to other nutrient elements. Aims: The aim of this research is to examine the effect of various qualities and dose of litter on the dynamics of N mineral soil and soil nitrification potential on maize cultivation system. Method: The treatment is set by Randomized Completely Block Design (RCBD). Four kinds of litter is chosen to represent the groups of low quality (Tectona grandis and Pterocarpus indicus) and the groups of high quality (Oryza sativa and Eupatorium inulifolium) are given on four doses: 4, 8, 12 and 16 mg/Ha. All treatments are fertilized with urea 150 kg/Ha. Variables measured include the soil concentration of NH4- and NO3-, potential nitrification conducted in 2, 4, 6, 8 and 10 weeks after planting the corn. Result: The research shows that the addition of low-quality litter is influenced very significantly by release of NH4-, formation of NO3- and potential nitrification of soil. Others results show that the content of litter (lignin, polyphenol and C/N ratio) has the most powerful influence as regulator of NH4- released (p NO3- (p < 0.01) and potential nitrification of soil (p < 0.01) rather than the content of lignin, polyphenol and C/N ratio of litter separately. Conclusion: The conclusion of this research is that the management of litter quality input can be applied in the field to regulate the process of nitrification in soil and potential to increase N used efficiency of corn plant.
文摘Enriched by the-medium containingchitin and cell wall of Phizoctoniasolani AG-1,a bacterium X2-23 withhigher chitinase activity was isolatedfrom 166 chitinase-producing bacteria.It could distinctly inhibit the fungi
基金Supported by the Natural Science Foundation of Fujian Province (No.E0310019) and Key Project of Science and Technology of Fujian Province (No.2003H023).
文摘The kinetics of asymmetric production of R-（-）-mandelic acid （R-MA） from phenylglyoxylic acid （PGA） catalyzed by Saccharomyces cerevisiae sp. strain FD11b was studied by fed-batch cultures. The concentrations of glucose and PGA were controlled respectively with a dual feeding system. When the electron donor glucose was supplied at the rate of 0.0833mmol·gdw^-1·h^-1, the specific production rate （qp） and the enantiomeric excess of R-MA reached the maximum 0.353mmol·gdw^-1·h^-1 and 97.1%, respectively. The apparent reduction activity of yeast FD 11 b was obviously affected by both substrate PGA and product MA. The qp value reached the maximum 0.36-0.38mmol·gdw^-1·h^-1 when the PGA concentration was controlled between 25 and 35mmol·L^-1. The obvious substrate inhibition of bioconversion was observed at the PGA concentrations higher than 40mmol·L^-1. The accumulation of product MA also caused a severe feed-back inhibition for its production when the product concentration was above 60mmol·L^-1. The kinetic model with the inhibition effect of both substrate and product was simulated by a computer-based least-square arithrnatic. The established kinetic model was in good agreement with the experimental data.
基金Support by the National Natural Science Foundation of China(Nos.21002054, 20572054)the Research Fund for the Doctoral Programme of Higher Education of China(No.20100031120016)the Fundamental Research Funds for the Central Universities of China
文摘The authors synthesized a series of novel 5-heterocycloxy-3-substituted-1-（3-trifluoromethyl）phenyl-1H- pyrazole derivatives. Herbicidal activities of the two intermediate compounds and thirteen target compounds were evaluated via Brassica napus and Echinochloa crusgalli（L.） Beauv tests. Bioassay results show that some of the compounds exhibit better inhibiting activities against Brassica napus and some of the compounds exhibit bleaching activities against Echinochloa crusgalli（L.） Beauv at 100 μg/mL.
基金Supported by the National Natural Science Foundation of China (30430190, 30625011)973 (2007CB914304)Young Talent Programme of Fujian Province (2007F3119)
文摘Urokinase-type plasminogen activator （uPA） is a trypsin-like serine protease and plays a key role in several biological processes, including tissue remodeling, cell migration, and matrix degradation. The inhibitors of uPA have been shown to prevent the spread of metastasis and tumor growth, and accordingly uPA is widely recognized as a target for the treatment of cancer. In this work, we report the crystal structures of the complexes of uPA with its inhibitors： 4- （aminomethyl）-benzoic acid （AMBA） and 4-（aminomethyl-phenyl）-methanol （AMPM）, both at a resolution of 2.35 А. The inhibitory constants of these two inhibitors were measured by a chromogenic competitive assay, and it was found that AMBA is a better inhibitor for uPA （Ki = 2.68 mM） than AMPM （Ki = 13.99 mM）. The structural study shows that the binding mode of inhibitor AMBA on uPA is similar to that of AMPM on uPA, both docked into the active site S1 pocket of uPA. Structural details of these complexes are provided to explain the difference of inhibitory constants.
