The stir casting technique was used to fabricate aluminum2024matrix hybrid composites reinforced with SiC(5%,mass fraction)and red mud(5%-20%,mass fraction)particles.The developed composites were characterized by usin...The stir casting technique was used to fabricate aluminum2024matrix hybrid composites reinforced with SiC(5%,mass fraction)and red mud(5%-20%,mass fraction)particles.The developed composites were characterized by using scanning electron microscopy(SEM)and electron dispersive spectrum(EDS)techniques.Further,Taguchi’s approach of experimental design was used to examine the tensile strength of the hybrid composites(with minimum number of experiments).It was found that the reinforcing particles were well dispersed and adequately bonded in the hybrid composites.The density and porosity of the hybrid composites were reduced with the increase in reinforcement content.The tensile strength of the composites increased with the increase in the red mud content and the ageing time.The developed model indicated that the red mud content had the highest influence on the tensile strength response followed by the ageing time.Overall,it was found that Al2024/SiC/red mud composites exhibited superior tensile strength(about34%higher)in comparison to the Al2024alloy under optimized conditions.展开更多
Mg-4 Li-3(Al-Si),Mg-8 Li-3(Al-Si)and Mg-12 Li-3(Al-Si)alloys based on theα-Mg,α-Mg+β-Li,β-Li phases,respectively,were produced to investigate the effect of alloying with Al-Si eutectic on the microstructure and me...Mg-4 Li-3(Al-Si),Mg-8 Li-3(Al-Si)and Mg-12 Li-3(Al-Si)alloys based on theα-Mg,α-Mg+β-Li,β-Li phases,respectively,were produced to investigate the effect of alloying with Al-Si eutectic on the microstructure and mechanical properties of the three alloys.Alloying with the Al-Si eutectic of Mg-xLi(x=4,8 and 12 wt.%)alloys caused the formation of different types of Al-Li precipitates:Al3Li,AlLi and Li3Al2,respectively.Also,considerable quantities of Mg2Si phase particles were found in the three alloys.The results of tensile tests showed that the Mg-4Li-3(Al-Si)alloy exhibited the highest ultimate tensile strength(UTS)of 249 MPa but the lowest elongation of 6.3%.The Mg-12Li-3(Al-Si)alloy had the highest elongation of 26%but the lowest UTS of 173 MPa.The different mechanical properties were attributed to the different crystal structures of the three alloys and the precipitate with different type,morphology and distribution.展开更多
Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at t...Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at temperatures between 200 and 600 ℃ for 60 min. The results show that the microstructure of tempered sample at 200 ℃ mainly consists of tempered martensite. With increasing the tempered temperature, the martensite transforms to the ferrite and carbides. The ultimate tensile strength, the hardness and the retained austenite decrease with increasing tempered temperature, and 0.2% yield strength increases when the temperature increases from 200 to 300 ℃ and then decreases with increasing the temperature, but the elongation and impact energy increase with increasing the tempering temperature.展开更多
An attempt was made to optimize friction welding parameters to attain a minimum hardness at the interface and a maximum tensile strength of the dissimilar joints of AISI 304 austenitic stainless steel (ASS) and copp...An attempt was made to optimize friction welding parameters to attain a minimum hardness at the interface and a maximum tensile strength of the dissimilar joints of AISI 304 austenitic stainless steel (ASS) and copper (Cu) alloy using response surface methodology (RSM). Three-factor, five-level central composite design matrix was used to specify experimental conditions. Twenty joints were fabricated using ASS and Cu alloy. Tensile strength and interface hardness were measured experimentally. Analysis of variance (ANOVA) method was used to find out significant main and interaction parameters and empirical relationships were developed using regression analysis. The friction welding parameters were optimized by constructing response graphs and contour plots using design expert software. The developed empirical relationships can be effectively used to predict tensile strength and interface hardness of friction welded ASS-Cu joints at 95% confidence level. The developed contour plots can be used to attain required level of optimum conditions to join ASS-Cu alloy by friction welding process.展开更多
The study included 200 thalassemia patients, 120 (60%) males and 80 (40%) females, at age 2-30 years the mean age 16 years and 100 persons from blood donors at age 20-50 years, the mean age 35 years, as control gr...The study included 200 thalassemia patients, 120 (60%) males and 80 (40%) females, at age 2-30 years the mean age 16 years and 100 persons from blood donors at age 20-50 years, the mean age 35 years, as control group. The authors used ELISA HCV 3.0 to detect anti-HCV in serum of thalassemia patients and blood donors. The results show 17% positive, 76% negative and 7% equivocal in serum ofthalassemia patients, but show 1% positive, 98% negative, 1% equivocal in serum of blood donors. The results show significant difference in P ≤ 0.05 between prevalence of anti-HCV antibodies among thalassemia patients and blood donors, the confirmatory tests by recombinant immunoblot assay version 3.0 (RIBA) show 17.5% positive, 79% negative and 3.5% equivocal in serum of thalassemia patients but show 2% positive, 98% negative in serum of blood donors. The thalassemia patients in the present study region had high seroprevalence of anti-HCV.展开更多
The sera of 180 human samples were tested for the presence of antibodies against Borrelia burgdorferi using the ELISA (enzyme-linked immunosorbent assay) technique. Out of 180 sero-samples, 46 (25.55%) were positi...The sera of 180 human samples were tested for the presence of antibodies against Borrelia burgdorferi using the ELISA (enzyme-linked immunosorbent assay) technique. Out of 180 sero-samples, 46 (25.55%) were positive. Females of the age range 18-35 years had the highest rate of sero-positive samples 14 (38.88%), while the highest percentage of sero-negative samples was found in males of the age range 50-80 years. The other sero-positive samples were: 6 (26.08%), 6 (25%) and 3 (11.53%) in males of ages between 18-35, 35-50 and 50-80 years, respectively, and 11 (29.72%) and 6 (17.64%) in females in the age ranges 35-50 and 50-80 years, respectively. The mean concentration of Anti- B. burgdorferi antibody was higher (16.7 U/mL) when compared with mean concentration of normal value (5.5 U/mL), P 〈 0.001.展开更多
Vaccines are used in integrated control strategies to guard poultry against H5N1 high-pathogenicity avian influenza (AI). This study was to evaluate the efficacy of AI vaccine against AI in poultry. About 400 serum ...Vaccines are used in integrated control strategies to guard poultry against H5N1 high-pathogenicity avian influenza (AI). This study was to evaluate the efficacy of AI vaccine against AI in poultry. About 400 serum samples were collected from the selected 130 farms located at Rajshahi region, Bangladesh. The study was carried out from January, 2013 to January, 2015. The AI vaccine titres were compared in different breed of layer, environmental temperature, feed and egg production. Result showed that the value of titres (mean ± SD) in Hyline brown, Hyline white, Bovans white and Novogen white were 6.71 ± 0.05, 6.67 ± 0.06, 6.79 ± 0.03 and 6.43 ± 0.04, respectively. The highest serum antibody titres were 6.61 ± 0.24 against AI antibody in 〉 26 ℃ environment temperature. The highest and lowest serum antibody value of AI against feed brand (nutrient) were 7.75 ± 0.08 and 5.58 ± 0.22 for Aftab and Quality brand feed, respectively.展开更多
In this study, we developed a novel liposomal delivery system modified by Tat peptide and wheat germ agglutinin(WGA) with antimicrobial effect. Physicochemical parameters, in vitro antimicrobial, time-kill study, ce...In this study, we developed a novel liposomal delivery system modified by Tat peptide and wheat germ agglutinin(WGA) with antimicrobial effect. Physicochemical parameters, in vitro antimicrobial, time-kill study, cellular uptake, biofilm formation inhibition and in vivo antibacterial efficacy against Methicillin-resistant Staphylococcus aureus(MRSA) were investigated. Minimum inhibitory concentrations(MICs) and colony-forming units(CFUs) in the time-kill study for Tat-WGA-modified liposomal clarithromycin(CLA-Tat WGALip) were lower than those of free and other modified liposomal CLA. Flow cytometry analysis disclosed that Tat WGALip delivered more coumarin 6 into bacteria. Furthermore, Tat-WGA-modified liposomal CLA efficiently inhibited the formation of MRSA biofiom. CFU of MRSA in the abscess of mice treated with CLA-Tat WGALip was significantly lower than that of any others(P〈0.01). Collectively, liposomal delivery system modified by Tat and WGA could be a promising anti-resistant infection strategy.展开更多
We reported herein the synthesis and antibacterial activity evaluation of two oxazolidinone-deferasirox conjugates with different linkers that were designed based on the“Trojan horse”strategy.The conjugates could co...We reported herein the synthesis and antibacterial activity evaluation of two oxazolidinone-deferasirox conjugates with different linkers that were designed based on the“Trojan horse”strategy.The conjugates could combine with Fe^(3+)ions as the deferasirox.However,both conjugates were inactive against tested bacteria,including S.aureus,E.coli,A.baumannii,and P.aeruginosa.The results suggested that the synthesized iron chelator deferasirox was not suitable as a siderophore of the bacteria to transport the antibiotic,or the coupling linker of the synthesized conjugates could not be hydrolyzed to release the oxazolidinone in the cytoplasm.Therefore,the design and synthesis of oxazolidinone-deferasirox conjugates need further exploration.展开更多
文摘The stir casting technique was used to fabricate aluminum2024matrix hybrid composites reinforced with SiC(5%,mass fraction)and red mud(5%-20%,mass fraction)particles.The developed composites were characterized by using scanning electron microscopy(SEM)and electron dispersive spectrum(EDS)techniques.Further,Taguchi’s approach of experimental design was used to examine the tensile strength of the hybrid composites(with minimum number of experiments).It was found that the reinforcing particles were well dispersed and adequately bonded in the hybrid composites.The density and porosity of the hybrid composites were reduced with the increase in reinforcement content.The tensile strength of the composites increased with the increase in the red mud content and the ageing time.The developed model indicated that the red mud content had the highest influence on the tensile strength response followed by the ageing time.Overall,it was found that Al2024/SiC/red mud composites exhibited superior tensile strength(about34%higher)in comparison to the Al2024alloy under optimized conditions.
基金Projects(51971040,51701029,51671041,51531002) supported by the National Natural Science Foundation of ChinaProject(2016YFB0301100) supported by the National Key Research and Development Program of China+2 种基金Projects(2018T110943,2017M620410) supported by the China Postdoctoral Science FoundationProject(Xm2017010) supported by the the Chongqing Postdoctoral Scientific Research Foundation,ChinaProject(2018CDGFCL005) supported by the Fundamental Research Funds for the Central Universities,China
文摘Mg-4 Li-3(Al-Si),Mg-8 Li-3(Al-Si)and Mg-12 Li-3(Al-Si)alloys based on theα-Mg,α-Mg+β-Li,β-Li phases,respectively,were produced to investigate the effect of alloying with Al-Si eutectic on the microstructure and mechanical properties of the three alloys.Alloying with the Al-Si eutectic of Mg-xLi(x=4,8 and 12 wt.%)alloys caused the formation of different types of Al-Li precipitates:Al3Li,AlLi and Li3Al2,respectively.Also,considerable quantities of Mg2Si phase particles were found in the three alloys.The results of tensile tests showed that the Mg-4Li-3(Al-Si)alloy exhibited the highest ultimate tensile strength(UTS)of 249 MPa but the lowest elongation of 6.3%.The Mg-12Li-3(Al-Si)alloy had the highest elongation of 26%but the lowest UTS of 173 MPa.The different mechanical properties were attributed to the different crystal structures of the three alloys and the precipitate with different type,morphology and distribution.
基金Project(2011BAE13B03) supported by the National Key Technology R&D Program of China
文摘Effect of tempering temperature on the microstructure and mechanical properties of AISI 6150 steel was investigated. All samples were austenitized at 870 ℃ for 45 min followed by oil quenching, and then tempered at temperatures between 200 and 600 ℃ for 60 min. The results show that the microstructure of tempered sample at 200 ℃ mainly consists of tempered martensite. With increasing the tempered temperature, the martensite transforms to the ferrite and carbides. The ultimate tensile strength, the hardness and the retained austenite decrease with increasing tempered temperature, and 0.2% yield strength increases when the temperature increases from 200 to 300 ℃ and then decreases with increasing the temperature, but the elongation and impact energy increase with increasing the tempering temperature.
文摘An attempt was made to optimize friction welding parameters to attain a minimum hardness at the interface and a maximum tensile strength of the dissimilar joints of AISI 304 austenitic stainless steel (ASS) and copper (Cu) alloy using response surface methodology (RSM). Three-factor, five-level central composite design matrix was used to specify experimental conditions. Twenty joints were fabricated using ASS and Cu alloy. Tensile strength and interface hardness were measured experimentally. Analysis of variance (ANOVA) method was used to find out significant main and interaction parameters and empirical relationships were developed using regression analysis. The friction welding parameters were optimized by constructing response graphs and contour plots using design expert software. The developed empirical relationships can be effectively used to predict tensile strength and interface hardness of friction welded ASS-Cu joints at 95% confidence level. The developed contour plots can be used to attain required level of optimum conditions to join ASS-Cu alloy by friction welding process.
文摘The study included 200 thalassemia patients, 120 (60%) males and 80 (40%) females, at age 2-30 years the mean age 16 years and 100 persons from blood donors at age 20-50 years, the mean age 35 years, as control group. The authors used ELISA HCV 3.0 to detect anti-HCV in serum of thalassemia patients and blood donors. The results show 17% positive, 76% negative and 7% equivocal in serum ofthalassemia patients, but show 1% positive, 98% negative, 1% equivocal in serum of blood donors. The results show significant difference in P ≤ 0.05 between prevalence of anti-HCV antibodies among thalassemia patients and blood donors, the confirmatory tests by recombinant immunoblot assay version 3.0 (RIBA) show 17.5% positive, 79% negative and 3.5% equivocal in serum of thalassemia patients but show 2% positive, 98% negative in serum of blood donors. The thalassemia patients in the present study region had high seroprevalence of anti-HCV.
文摘The sera of 180 human samples were tested for the presence of antibodies against Borrelia burgdorferi using the ELISA (enzyme-linked immunosorbent assay) technique. Out of 180 sero-samples, 46 (25.55%) were positive. Females of the age range 18-35 years had the highest rate of sero-positive samples 14 (38.88%), while the highest percentage of sero-negative samples was found in males of the age range 50-80 years. The other sero-positive samples were: 6 (26.08%), 6 (25%) and 3 (11.53%) in males of ages between 18-35, 35-50 and 50-80 years, respectively, and 11 (29.72%) and 6 (17.64%) in females in the age ranges 35-50 and 50-80 years, respectively. The mean concentration of Anti- B. burgdorferi antibody was higher (16.7 U/mL) when compared with mean concentration of normal value (5.5 U/mL), P 〈 0.001.
文摘Vaccines are used in integrated control strategies to guard poultry against H5N1 high-pathogenicity avian influenza (AI). This study was to evaluate the efficacy of AI vaccine against AI in poultry. About 400 serum samples were collected from the selected 130 farms located at Rajshahi region, Bangladesh. The study was carried out from January, 2013 to January, 2015. The AI vaccine titres were compared in different breed of layer, environmental temperature, feed and egg production. Result showed that the value of titres (mean ± SD) in Hyline brown, Hyline white, Bovans white and Novogen white were 6.71 ± 0.05, 6.67 ± 0.06, 6.79 ± 0.03 and 6.43 ± 0.04, respectively. The highest serum antibody titres were 6.61 ± 0.24 against AI antibody in 〉 26 ℃ environment temperature. The highest and lowest serum antibody value of AI against feed brand (nutrient) were 7.75 ± 0.08 and 5.58 ± 0.22 for Aftab and Quality brand feed, respectively.
基金The National Natural Science Foundation of China(Grant No.81202488)
文摘In this study, we developed a novel liposomal delivery system modified by Tat peptide and wheat germ agglutinin(WGA) with antimicrobial effect. Physicochemical parameters, in vitro antimicrobial, time-kill study, cellular uptake, biofilm formation inhibition and in vivo antibacterial efficacy against Methicillin-resistant Staphylococcus aureus(MRSA) were investigated. Minimum inhibitory concentrations(MICs) and colony-forming units(CFUs) in the time-kill study for Tat-WGA-modified liposomal clarithromycin(CLA-Tat WGALip) were lower than those of free and other modified liposomal CLA. Flow cytometry analysis disclosed that Tat WGALip delivered more coumarin 6 into bacteria. Furthermore, Tat-WGA-modified liposomal CLA efficiently inhibited the formation of MRSA biofiom. CFU of MRSA in the abscess of mice treated with CLA-Tat WGALip was significantly lower than that of any others(P〈0.01). Collectively, liposomal delivery system modified by Tat and WGA could be a promising anti-resistant infection strategy.
基金The CAMS Innovation Fund for Medical Sciences(CIFMS 2021-I2M-1-028).
文摘We reported herein the synthesis and antibacterial activity evaluation of two oxazolidinone-deferasirox conjugates with different linkers that were designed based on the“Trojan horse”strategy.The conjugates could combine with Fe^(3+)ions as the deferasirox.However,both conjugates were inactive against tested bacteria,including S.aureus,E.coli,A.baumannii,and P.aeruginosa.The results suggested that the synthesized iron chelator deferasirox was not suitable as a siderophore of the bacteria to transport the antibiotic,or the coupling linker of the synthesized conjugates could not be hydrolyzed to release the oxazolidinone in the cytoplasm.Therefore,the design and synthesis of oxazolidinone-deferasirox conjugates need further exploration.