The influence of pile-up on the nanoindentation measurements in Cu 2wt.%Be samples with precipitates was carefully studied.The precipitates were formed by aging treatments for 1 h at different temperatures between 540...The influence of pile-up on the nanoindentation measurements in Cu 2wt.%Be samples with precipitates was carefully studied.The precipitates were formed by aging treatments for 1 h at different temperatures between 540 and 680 K.The load depth curves were analyzed using the classical Oliver and Pharr method,and the obtained elastic modulus and hardness were compared with values estimated by other techniques.An important level of pile-up was found in samples with precipitates and differences in the load depth curves were observed between the unaged and aged samples.A correction of the contact depth considering the pile-up proposed by Loubet was used for hardness estimation.For the determination of the elastic modulus,an approach based on the relation between the ratio of unloading work to indentation total work,with the ratio H/Er(H is the hardness;Er is the reduced modulus),was employed.A specific relation between both parameters was developed.展开更多
The aim of this research was to develop effective alternative therapies to reduce antibiotic use in animal agriculture. In this study, the efficacy of copper-modified palygorskite（CM-Pal） in preventing diarrhea caus...The aim of this research was to develop effective alternative therapies to reduce antibiotic use in animal agriculture. In this study, the efficacy of copper-modified palygorskite（CM-Pal） in preventing diarrhea caused by Salmonella was specifically examined both in vitro and in vivo. The CM-Pal was prepared with palygorskite（Pal） and copper nitrate. The antibacterial activity of the CM-Pal was detected by comparing the differences in cell numbers on plate count agar before and after adding the CM-Pal to Salmonella typhimurium cultures. Seventy ICR mice were then allocated into seven groups. Five groups（the treatment groups） were infected with S. typhimurium by intraperitoneal（i.p.） injection and were given Pal, CM-Pal, montmorillonite powder, gentamicin, and physiological saline, respectively. One group（the prevention group） was given CM-Pal before infection with S. typhimurium. Another group（the uninfected group） was not infected with S. typhimurium. The effects of Pal, CM-Pal, montmorillonite powder, and gentamicin on the treatment or prevention of diarrhea in the mice were examined by stool studies, fecal scoring, and assessment of growth performance and villus height. The CM-Pal had satisfactory anti-bacterial properties in vitro： the antibacterial rate was 100% after 2 h incubation with S. typhimurium NJS1 cultures（1×10-6 colony-forming units（CFU）/ml）. In the in vivo experiment, the CM-Pal exerted superior effects in the treatment and prevention of diarrhea in mice compared with Pal, montmorillonite powder, and gentamicin. In the CM-Pal group, no mice showed signs of diarrhea at 24 h post infection（p.i.）, and all mice fully recovered from infection. However, the Pal group, montmorillonite group, and gentamicin group only recovered after 48, 48, and 96 h, respectively. The villus height level in the CM-Pal treatment group recovered at 3 d p.i. However, the recovery time of the other groups was longer（at least 5 d）. The CM-Pal prevention group had a better effect on weight gain than the other groups. This study suggested that CM-Pal may be an effective alternative to conventional antibiotics for the treatment and prevention of animal diarrhea caused by Salmonella.展开更多
基金supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CICPBA)SECAT (UNCPBA) Argentina
文摘The influence of pile-up on the nanoindentation measurements in Cu 2wt.%Be samples with precipitates was carefully studied.The precipitates were formed by aging treatments for 1 h at different temperatures between 540 and 680 K.The load depth curves were analyzed using the classical Oliver and Pharr method,and the obtained elastic modulus and hardness were compared with values estimated by other techniques.An important level of pile-up was found in samples with precipitates and differences in the load depth curves were observed between the unaged and aged samples.A correction of the contact depth considering the pile-up proposed by Loubet was used for hardness estimation.For the determination of the elastic modulus,an approach based on the relation between the ratio of unloading work to indentation total work,with the ratio H/Er(H is the hardness;Er is the reduced modulus),was employed.A specific relation between both parameters was developed.
基金supported by the Foundation of Key Laboratory for Palygorskite Science and Applied Technology of Jiangsu Province(No.HPK201506)the Natural Science Foundation of Jiangsu Province(No.BK20130686)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘The aim of this research was to develop effective alternative therapies to reduce antibiotic use in animal agriculture. In this study, the efficacy of copper-modified palygorskite（CM-Pal） in preventing diarrhea caused by Salmonella was specifically examined both in vitro and in vivo. The CM-Pal was prepared with palygorskite（Pal） and copper nitrate. The antibacterial activity of the CM-Pal was detected by comparing the differences in cell numbers on plate count agar before and after adding the CM-Pal to Salmonella typhimurium cultures. Seventy ICR mice were then allocated into seven groups. Five groups（the treatment groups） were infected with S. typhimurium by intraperitoneal（i.p.） injection and were given Pal, CM-Pal, montmorillonite powder, gentamicin, and physiological saline, respectively. One group（the prevention group） was given CM-Pal before infection with S. typhimurium. Another group（the uninfected group） was not infected with S. typhimurium. The effects of Pal, CM-Pal, montmorillonite powder, and gentamicin on the treatment or prevention of diarrhea in the mice were examined by stool studies, fecal scoring, and assessment of growth performance and villus height. The CM-Pal had satisfactory anti-bacterial properties in vitro： the antibacterial rate was 100% after 2 h incubation with S. typhimurium NJS1 cultures（1×10-6 colony-forming units（CFU）/ml）. In the in vivo experiment, the CM-Pal exerted superior effects in the treatment and prevention of diarrhea in mice compared with Pal, montmorillonite powder, and gentamicin. In the CM-Pal group, no mice showed signs of diarrhea at 24 h post infection（p.i.）, and all mice fully recovered from infection. However, the Pal group, montmorillonite group, and gentamicin group only recovered after 48, 48, and 96 h, respectively. The villus height level in the CM-Pal treatment group recovered at 3 d p.i. However, the recovery time of the other groups was longer（at least 5 d）. The CM-Pal prevention group had a better effect on weight gain than the other groups. This study suggested that CM-Pal may be an effective alternative to conventional antibiotics for the treatment and prevention of animal diarrhea caused by Salmonella.
