Aims: The objective of this study was to investigate the effect of free fatty acid length chain and unsaturated bond number on the heat resistance and recovery media of bacterial spores. Methods and results: For 6 spe...Aims: The objective of this study was to investigate the effect of free fatty acid length chain and unsaturated bond number on the heat resistance and recovery media of bacterial spores. Methods and results: For 6 species, bacterial spore heat resistances were estimated at different free fatty acid concentrations added to heating media or in recovery media. The addition of free fatty acids to heating media has a slight influence on the heat resistance of bacterial spores whatever the species or type of acid studied. On the contrary, the addition of free fatty acids to the recovery medium after the heat treatment greatly reduces the ability to bacterial spores to recover and form colonies. This effect varies depending on chain length, unsaturated bond number of fatty acid and on the bacterial strain studied. Conclusion: The presence of free acids in the recovery media is an additive stress which decreases the capability of injured spores to germinate and grow thereafter. Significance and impact of this study: The impact of free fatty acids presented in this study can be taken into account to reduce the thermal intensity of food sterilization in relation to their availability in food matrix.展开更多
In this paper, an antenna with reconfigurable band notches, for cognitive radio applications, is proposed. The antenna can be operated as ultra wideband, and is reconfigurable in terms of the ability to select a notch...In this paper, an antenna with reconfigurable band notches, for cognitive radio applications, is proposed. The antenna can be operated as ultra wideband, and is reconfigurable in terms of the ability to select a notched band in the SRR resonant frequency. The reconfigurable band notches are induced using a band-stop filter based on split-ring resonators (SRRs), and are controlled using electronic switches mounted over the SRRs. For this sake, the design of the band-stop filter is proposed. A prototype of filter is fabricated and measured. The incorporation of a band-stop filter, into a wideband antenna, is then looked into. The proposed antenna is designed and simulated using Ansoft HFSS. A prototype of the antenna is fabricated and measured. A good analogy between simulated and measured results is obtained.展开更多
The study of sperm cellular components at molecular level is crucial for the diagnosis of male unexplained infertility. The aim of the study was to compare the molecular profile of steroid receptors and aromatase in s...The study of sperm cellular components at molecular level is crucial for the diagnosis of male unexplained infertility. The aim of the study was to compare the molecular profile of steroid receptors and aromatase in spermatozoa obtained from two normozoospermic groups of patients issued from couples treated for infertility. We investigated 46 male patients from unexplained infertility couples and from men, 38 where female partners presented with tubal infertility. Sperm ERs (estrogen receptors: alpha and beta), GPER (G protein-coupled estrogen receptor), AR (androgen receptor) and aromatase mRNA expression levels by TaqMan qPCR were analyzed. AR transcript level was significantly lower in sperm of men from unexplained infertility couples vs. men from couples with tubal factor infertility (P = 0.04). Although the AR mRNA expression level did not had any effect on embryo development and its implantation, a significant correlation between AR mRNA levels and clinical pregnancy in unexplained infertility patients was observed. Taken together, AR transcript presence in ejaculated spermatozoa could be a potential marker for unexplained infertility.展开更多
Reinforced polymer-matrix composites are widely used under sliding contact conditions in various boating and automotive applications.In this paper,the friction and wear of bulk epoxy and carbon filler reinforced epoxy...Reinforced polymer-matrix composites are widely used under sliding contact conditions in various boating and automotive applications.In this paper,the friction and wear of bulk epoxy and carbon filler reinforced epoxy composites have been investigated using a pin-on-disc tribometer.The effect of different fillers on the tribological behavior of an epoxy has been studied using treated and untreated carbon nanotubes,graphite,and a mixture of graphite and carbon nanotubes.Filler addition greatly enhances the tribological properties of the epoxy resin,by reducing the friction coefficient and the wear rate.In addition,it was found that the treated carbon nanotubes/epoxy composites have the best tribological behavior.Moreover,a correlation between contact temperature and friction coefficient is reported.Finally the wear mechanisms were determined by scanning electronic microscopy.展开更多
Landscape changes are known to exacerbate the impacts of climate change. As such, understanding the combined effect of climate and landscape on agroecosystems is vital if we are to maintain the fimction of agroecosyst...Landscape changes are known to exacerbate the impacts of climate change. As such, understanding the combined effect of climate and landscape on agroecosystems is vital if we are to maintain the fimction of agroecosystems. This study aimed to elucidate the effects of agricultural landscape complexity on the microclimate and thermal tolerance of an aphid pest to better understand how landscape and climate may interact to affect the thermal tolerance of pest species within the context of global climate change. Meteo- rological data were measured at the landscape level, and cereal aphids （Sitobion avenae, Metopolophium dirhodum and Rhopalosiphum padi） sampled, from contrasting landscapes （simple and complex） in winter 2013/2014 and spring 2014 in cereal fields of Brittany, France. Aphids were returned to the laboratory and the effect of landscape of origin on aphid cold tolerance （as determined by CTmin） was investigated. Results revealed that local landscape complexity significantly affected microclimate, with simple homogenous landscapes being on average warmer, but with greater temperature variation. Landscape complexity was shown to impact aphid cold tolerance, with aphids from complex land- scapes being more cold tolerant than those from simple landscapes in both winter and spring, but with differences among species. This study highlights that future changes to land use could have implications for the thermal tolerance and adaptability of insects. Fur- thermore, not all insect species respond in a similar way to microhabitat and microclimate, which could disrupt important predator-prey relationships and the ecosystem service they provide.展开更多
In this paper, we present a mathematical model that describes tumor-normal cells inter- action dynamics focusing on role of drugs in treatment of brain tumors. The goal is to predict distribution and necessary quantit...In this paper, we present a mathematical model that describes tumor-normal cells inter- action dynamics focusing on role of drugs in treatment of brain tumors. The goal is to predict distribution and necessary quantity of drugs delivered in drug-therapy by using optimal control framework. The model describes interactions of tumor and normal cells using a system of reactions^diffusion equations involving the drug concentration, tumor cells and normal tissues. The control estimates simultaneously blood perfusion rate, reabsorption rate of drug and drug dosage administered, which affect the effects of brain tumor chemotherapy. First, we develop mathematical framework which mod- els the competition between tumor and normal cells under chemotherapy constraints. Then, existence, uniqueness and regularity of solution of state equations are proved as well as stability results. Afterwards, optimal control problems are formulated in order to minimize the drug delivery and tumor cell burden in different situations. We show existence and uniqueness of optimal solution, and we derive necessary conditions for optimality. Finally, to solve numerically optimal control and optimization problems, we propose and investigate an adjoint multiple-relaxation-time lattice Boltzmann method for a general nonlinear coupled anisotropic convection-diffusion system （which includes the developed model for brain tumor targeted drug delivery system）.展开更多
文摘Aims: The objective of this study was to investigate the effect of free fatty acid length chain and unsaturated bond number on the heat resistance and recovery media of bacterial spores. Methods and results: For 6 species, bacterial spore heat resistances were estimated at different free fatty acid concentrations added to heating media or in recovery media. The addition of free fatty acids to heating media has a slight influence on the heat resistance of bacterial spores whatever the species or type of acid studied. On the contrary, the addition of free fatty acids to the recovery medium after the heat treatment greatly reduces the ability to bacterial spores to recover and form colonies. This effect varies depending on chain length, unsaturated bond number of fatty acid and on the bacterial strain studied. Conclusion: The presence of free acids in the recovery media is an additive stress which decreases the capability of injured spores to germinate and grow thereafter. Significance and impact of this study: The impact of free fatty acids presented in this study can be taken into account to reduce the thermal intensity of food sterilization in relation to their availability in food matrix.
文摘In this paper, an antenna with reconfigurable band notches, for cognitive radio applications, is proposed. The antenna can be operated as ultra wideband, and is reconfigurable in terms of the ability to select a notched band in the SRR resonant frequency. The reconfigurable band notches are induced using a band-stop filter based on split-ring resonators (SRRs), and are controlled using electronic switches mounted over the SRRs. For this sake, the design of the band-stop filter is proposed. A prototype of filter is fabricated and measured. The incorporation of a band-stop filter, into a wideband antenna, is then looked into. The proposed antenna is designed and simulated using Ansoft HFSS. A prototype of the antenna is fabricated and measured. A good analogy between simulated and measured results is obtained.
文摘The study of sperm cellular components at molecular level is crucial for the diagnosis of male unexplained infertility. The aim of the study was to compare the molecular profile of steroid receptors and aromatase in spermatozoa obtained from two normozoospermic groups of patients issued from couples treated for infertility. We investigated 46 male patients from unexplained infertility couples and from men, 38 where female partners presented with tubal infertility. Sperm ERs (estrogen receptors: alpha and beta), GPER (G protein-coupled estrogen receptor), AR (androgen receptor) and aromatase mRNA expression levels by TaqMan qPCR were analyzed. AR transcript level was significantly lower in sperm of men from unexplained infertility couples vs. men from couples with tubal factor infertility (P = 0.04). Although the AR mRNA expression level did not had any effect on embryo development and its implantation, a significant correlation between AR mRNA levels and clinical pregnancy in unexplained infertility patients was observed. Taken together, AR transcript presence in ejaculated spermatozoa could be a potential marker for unexplained infertility.
文摘Reinforced polymer-matrix composites are widely used under sliding contact conditions in various boating and automotive applications.In this paper,the friction and wear of bulk epoxy and carbon filler reinforced epoxy composites have been investigated using a pin-on-disc tribometer.The effect of different fillers on the tribological behavior of an epoxy has been studied using treated and untreated carbon nanotubes,graphite,and a mixture of graphite and carbon nanotubes.Filler addition greatly enhances the tribological properties of the epoxy resin,by reducing the friction coefficient and the wear rate.In addition,it was found that the treated carbon nanotubes/epoxy composites have the best tribological behavior.Moreover,a correlation between contact temperature and friction coefficient is reported.Finally the wear mechanisms were determined by scanning electronic microscopy.
文摘Landscape changes are known to exacerbate the impacts of climate change. As such, understanding the combined effect of climate and landscape on agroecosystems is vital if we are to maintain the fimction of agroecosystems. This study aimed to elucidate the effects of agricultural landscape complexity on the microclimate and thermal tolerance of an aphid pest to better understand how landscape and climate may interact to affect the thermal tolerance of pest species within the context of global climate change. Meteo- rological data were measured at the landscape level, and cereal aphids （Sitobion avenae, Metopolophium dirhodum and Rhopalosiphum padi） sampled, from contrasting landscapes （simple and complex） in winter 2013/2014 and spring 2014 in cereal fields of Brittany, France. Aphids were returned to the laboratory and the effect of landscape of origin on aphid cold tolerance （as determined by CTmin） was investigated. Results revealed that local landscape complexity significantly affected microclimate, with simple homogenous landscapes being on average warmer, but with greater temperature variation. Landscape complexity was shown to impact aphid cold tolerance, with aphids from complex land- scapes being more cold tolerant than those from simple landscapes in both winter and spring, but with differences among species. This study highlights that future changes to land use could have implications for the thermal tolerance and adaptability of insects. Fur- thermore, not all insect species respond in a similar way to microhabitat and microclimate, which could disrupt important predator-prey relationships and the ecosystem service they provide.
文摘In this paper, we present a mathematical model that describes tumor-normal cells inter- action dynamics focusing on role of drugs in treatment of brain tumors. The goal is to predict distribution and necessary quantity of drugs delivered in drug-therapy by using optimal control framework. The model describes interactions of tumor and normal cells using a system of reactions^diffusion equations involving the drug concentration, tumor cells and normal tissues. The control estimates simultaneously blood perfusion rate, reabsorption rate of drug and drug dosage administered, which affect the effects of brain tumor chemotherapy. First, we develop mathematical framework which mod- els the competition between tumor and normal cells under chemotherapy constraints. Then, existence, uniqueness and regularity of solution of state equations are proved as well as stability results. Afterwards, optimal control problems are formulated in order to minimize the drug delivery and tumor cell burden in different situations. We show existence and uniqueness of optimal solution, and we derive necessary conditions for optimality. Finally, to solve numerically optimal control and optimization problems, we propose and investigate an adjoint multiple-relaxation-time lattice Boltzmann method for a general nonlinear coupled anisotropic convection-diffusion system （which includes the developed model for brain tumor targeted drug delivery system）.
