Soil samples were taken from healthy tobacco plant rhizosphere in Phytophthora nicotianae severely infected tobacco field in Hunan Province to screen out antagonistic strains against Phytophthora nicotianae by the pla...Soil samples were taken from healthy tobacco plant rhizosphere in Phytophthora nicotianae severely infected tobacco field in Hunan Province to screen out antagonistic strains against Phytophthora nicotianae by the plate confrontation method.Subsequently,we had obtained a strain LZW-118 which had an obvious inhibitory effect on Phytophthora nicotianae with the plate inhibition rate of 71.14%.The strain LZW-118 was identified as Burkholderia vietnamiensis based on morphological,physiological and biochemical characteristics analysis and 16 S rDNA sequence.The growth-promoting potential test results showed that the strain not only had a significant inhibitory effect on Phytophthora nicotianae but also had the functions of nitrogen fixation,phosphorus dissolution and growth promotion for tobacco plant height,leaf length,leaf width and the number of leaves,showing a good application potential in biological control.展开更多
Networks are a class of general systems represented by becomes a weighted graph visualizing the constraints imposed their UC-structure. Suppressing the nature of elements the network by interconnections rather than th...Networks are a class of general systems represented by becomes a weighted graph visualizing the constraints imposed their UC-structure. Suppressing the nature of elements the network by interconnections rather than the elements themselves. These constraints follow generalized Kirchhoff＇s laws derived from physical constraints. Once we have a graph; then the working environment becomes the graph-theory. An algorithm derived from graph theory is developed within the paper in order to analyze general networks. The algorithm is based on computing all the spanning trees in the graph G with an associated weight. This weight is the product ofadmittance＇s of the edges forming the spanning tree. In the first phase this algorithm computes a depth first spanning tree together with its cotree. Both are used as parents for controlled generation of off-springs. The control is represented in selecting the off-springs that were not generated previously. While the generation of off-springs, is based on replacement of one or more tree edges by cycle edges corresponding to cotree edges. The algorithm can generate a frequency domain analysis of the network.展开更多
The interest for lipase production is due to the ability of this enzyme to catalyze some reactions, such as the transesterification. Although industrial biodiesel is produced chemically, there are several problems ass...The interest for lipase production is due to the ability of this enzyme to catalyze some reactions, such as the transesterification. Although industrial biodiesel is produced chemically, there are several problems associated with this technology that can be prevented through the use of lipases. The present work aimed to select microorganisms with potential for production of lipase with transesterification activity. The lipase from Burkholderia cepacia was the one with the most promising results for this type of reaction, showing results of hydrolytic activity at 37 ℃and pH 8.0. The pH and volume of crude enzyme extract that showed favorable for synthesis ofbiodiesel is at about pH 6.0 and 3.75 mL, respectively, which represents approximately 42% of water in the system, ensuring the conversion of nearly 60% to biodiesel.展开更多
The purposes of this study are to compare the proteome of Vibrio cholerae O139 strains with that of O22, O155 and El Tot biotype epidemic strains, and to identifv whether O139 strains have a close relation with the la...The purposes of this study are to compare the proteome of Vibrio cholerae O139 strains with that of O22, O155 and El Tot biotype epidemic strains, and to identifv whether O139 strains have a close relation with the latter. Proteins of two V. cholerae serogroup O139 strains, two El Tor biotype epidemic strains, one O22 strain, and one O155 strain were separated by two-dimensional gel electrophoresis （2-DE） ; the silver stained 2-DE gels were scanned with （ligital lmageScanner and analyzed with lmageMaster 2D Elite 3.10 software. Similarities of protein maps between these strains were analyzed. The two O139 strains had 86% proteins in common; the two El Tor biotype epidemie strains showed 84% proteins in common; O139 strains shared 67 % , 47 % and 45 % proteins with El Tor biotype epidemic strains, O22 and O 155 strains respectively. Although the proteome of O 139 strains have close similarity to that of El Tor biotype epidemic strains, great disparities exist. O139 strains may not originate from El Tor biotype directly, and a transition strain may exist.展开更多
The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. Also, the disease transmissions are getting more complicated and thus comprehensive strategies...The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. Also, the disease transmissions are getting more complicated and thus comprehensive strategies to implement public health control mea- sures are worthwhile to be investigated. In this paper, we aim to better understand the effects of HI states of vibrios from the environment and from human contacts that cause cholera outbreaks. We also present and analyze our cholera mathematical model with vaccine incorporated. Equilibrium analysis is conducted in the case with constant control for both epidemic and endemic dynamics. Optimal control theory is applied to seek cost-effective solutions of time-dependent vaccination strategies against cholera outbreaks. Our results show that using vaccination during cholera outbreaks at the very beginning of the onset can reduce the number of infections significantly.展开更多
This paper deals with the homogenization of a class of nonlinear elliptic problems with quadratic growth in a periodically perforated domain. The authors prescribe a Dirichlet condition on the exterior boundary and a ...This paper deals with the homogenization of a class of nonlinear elliptic problems with quadratic growth in a periodically perforated domain. The authors prescribe a Dirichlet condition on the exterior boundary and a nonhomogeneous nonlinear Robin condition on the boundary of the holes. The main difficulty, when passing to the limit, is that the solution of the problems converges neither strongly in L^2(Ω) nor almost everywhere in Ω. A new convergence result involving nonlinear functions provides suitable weak convergence results which permit passing to the limit without using any extension operator.Consequently, using a corrector result proved in [Chourabi, I. and Donato, P., Homogenization and correctors of a class of elliptic problems in perforated domains, Asymptotic Analysis, 92(1), 2015, 1–43, DOI: 10.3233/ASY-151288], the authors describe the limit problem, presenting a limit nonlinearity which is different for the two cases, that of a Neumann datum with a nonzero average and with a zero average.展开更多
文摘Soil samples were taken from healthy tobacco plant rhizosphere in Phytophthora nicotianae severely infected tobacco field in Hunan Province to screen out antagonistic strains against Phytophthora nicotianae by the plate confrontation method.Subsequently,we had obtained a strain LZW-118 which had an obvious inhibitory effect on Phytophthora nicotianae with the plate inhibition rate of 71.14%.The strain LZW-118 was identified as Burkholderia vietnamiensis based on morphological,physiological and biochemical characteristics analysis and 16 S rDNA sequence.The growth-promoting potential test results showed that the strain not only had a significant inhibitory effect on Phytophthora nicotianae but also had the functions of nitrogen fixation,phosphorus dissolution and growth promotion for tobacco plant height,leaf length,leaf width and the number of leaves,showing a good application potential in biological control.
文摘Networks are a class of general systems represented by becomes a weighted graph visualizing the constraints imposed their UC-structure. Suppressing the nature of elements the network by interconnections rather than the elements themselves. These constraints follow generalized Kirchhoff＇s laws derived from physical constraints. Once we have a graph; then the working environment becomes the graph-theory. An algorithm derived from graph theory is developed within the paper in order to analyze general networks. The algorithm is based on computing all the spanning trees in the graph G with an associated weight. This weight is the product ofadmittance＇s of the edges forming the spanning tree. In the first phase this algorithm computes a depth first spanning tree together with its cotree. Both are used as parents for controlled generation of off-springs. The control is represented in selecting the off-springs that were not generated previously. While the generation of off-springs, is based on replacement of one or more tree edges by cycle edges corresponding to cotree edges. The algorithm can generate a frequency domain analysis of the network.
文摘The interest for lipase production is due to the ability of this enzyme to catalyze some reactions, such as the transesterification. Although industrial biodiesel is produced chemically, there are several problems associated with this technology that can be prevented through the use of lipases. The present work aimed to select microorganisms with potential for production of lipase with transesterification activity. The lipase from Burkholderia cepacia was the one with the most promising results for this type of reaction, showing results of hydrolytic activity at 37 ℃and pH 8.0. The pH and volume of crude enzyme extract that showed favorable for synthesis ofbiodiesel is at about pH 6.0 and 3.75 mL, respectively, which represents approximately 42% of water in the system, ensuring the conversion of nearly 60% to biodiesel.
文摘The purposes of this study are to compare the proteome of Vibrio cholerae O139 strains with that of O22, O155 and El Tot biotype epidemic strains, and to identifv whether O139 strains have a close relation with the latter. Proteins of two V. cholerae serogroup O139 strains, two El Tor biotype epidemic strains, one O22 strain, and one O155 strain were separated by two-dimensional gel electrophoresis （2-DE） ; the silver stained 2-DE gels were scanned with （ligital lmageScanner and analyzed with lmageMaster 2D Elite 3.10 software. Similarities of protein maps between these strains were analyzed. The two O139 strains had 86% proteins in common; the two El Tor biotype epidemie strains showed 84% proteins in common; O139 strains shared 67 % , 47 % and 45 % proteins with El Tor biotype epidemic strains, O22 and O 155 strains respectively. Although the proteome of O 139 strains have close similarity to that of El Tor biotype epidemic strains, great disparities exist. O139 strains may not originate from El Tor biotype directly, and a transition strain may exist.
文摘The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. Also, the disease transmissions are getting more complicated and thus comprehensive strategies to implement public health control mea- sures are worthwhile to be investigated. In this paper, we aim to better understand the effects of HI states of vibrios from the environment and from human contacts that cause cholera outbreaks. We also present and analyze our cholera mathematical model with vaccine incorporated. Equilibrium analysis is conducted in the case with constant control for both epidemic and endemic dynamics. Optimal control theory is applied to seek cost-effective solutions of time-dependent vaccination strategies against cholera outbreaks. Our results show that using vaccination during cholera outbreaks at the very beginning of the onset can reduce the number of infections significantly.
文摘This paper deals with the homogenization of a class of nonlinear elliptic problems with quadratic growth in a periodically perforated domain. The authors prescribe a Dirichlet condition on the exterior boundary and a nonhomogeneous nonlinear Robin condition on the boundary of the holes. The main difficulty, when passing to the limit, is that the solution of the problems converges neither strongly in L^2(Ω) nor almost everywhere in Ω. A new convergence result involving nonlinear functions provides suitable weak convergence results which permit passing to the limit without using any extension operator.Consequently, using a corrector result proved in [Chourabi, I. and Donato, P., Homogenization and correctors of a class of elliptic problems in perforated domains, Asymptotic Analysis, 92(1), 2015, 1–43, DOI: 10.3233/ASY-151288], the authors describe the limit problem, presenting a limit nonlinearity which is different for the two cases, that of a Neumann datum with a nonzero average and with a zero average.
