The effect of a-mercapto-β-(2-furyl) acrylic acid (MFA, 200 mg/kg, oral) administered 30 min or 24 h post cadmium (1 mg/kg, i.p.) exposure on cadmium toxicity, was investigated in rats. The Cd induced hepatic metallo...The effect of a-mercapto-β-(2-furyl) acrylic acid (MFA, 200 mg/kg, oral) administered 30 min or 24 h post cadmium (1 mg/kg, i.p.) exposure on cadmium toxicity, was investigated in rats. The Cd induced hepatic metallothionein was reduced by MFA treatment parallel to the depletion of hepatic Cd. However, in renal tissue,MFA caused only redistribution of metal from the paniculate to the soluble fraction. Hepatic and renal Zn and renal Cu were significantly increased on Cd exposure. MFA therapy, however, lowered the hepatic Zn and increased the renal Cu levels. The action of MFA appears to be via metal chelation rather than by MT induction.展开更多
We investigate the influence of A1 preflow time on surface morphology and quality of AIN and GaN. The AIN and GaN layers are grown on a Si （111） substrate by metal organic chemical vapor deposition. Scanning electro...We investigate the influence of A1 preflow time on surface morphology and quality of AIN and GaN. The AIN and GaN layers are grown on a Si （111） substrate by metal organic chemical vapor deposition. Scanning electron microscopy, atomic force microscopy, x-ray diffraction and optical microscopy are used for analysis. Consequently, we find significant differences in the epitaxial properties of AlN buffer and the GaN layer, which are dependent on the AI preflow time. A1 preflow layers act as nucleation sites in the case of AiN growth. Compact and uniform AIN nucleation sites are observed with optimizing A1 preflow at an early nucleation stage, which will lead to a smooth AIN surface. Trenches and AlN grain clusters appear on the AIN surface while meltoback etching occurs on the GaN surface with excessive A1 preflow. The GaN quality variation keeps a similar trend with the AIN quality, which is influenced by AI preflow. With an optimized duration orAl preflow, crystal quality and surface morphology of AIN and GaN could be improved.展开更多
The middle class in metropolitan Chinese cities has become an important social group. With the rapid development of urbanization and constant advancement of suburbanization, the middle class has increasingly come to i...The middle class in metropolitan Chinese cities has become an important social group. With the rapid development of urbanization and constant advancement of suburbanization, the middle class has increasingly come to influence city traffic. Research into middle-class commuting activities thus has practical significance for improving traffic congestion and reducing the commuting burden in metropolitan cities. Based on a dataset formed by 816 completed surveys, this paper analyzes the commuting mode, time and distance of middle-class residents in Guangzhou City using the descriptive statistical method. The results indicate that private cars are the main commuting mode, followed by public transport. Meanwhile, middle-class residents mainly undertake medium-short time and medium-short distance commuting. The study subsequently uses multilevel logistic regression and multiple linear regression models to analyze the factors that influence commuting mode choice, time and distance. The gender, age, number of family cars, housing source and jobs-housing balance are the most important factors influencing commuting mode choice; housing, population density, jobs-housing balance and commuting mode significantly affect commuting time; and transport accessibility, jobs-housing balance and commuting mode are the notable factors affecting commuting distance. Finally, this paper analyzes what is affecting the commuting activities of middle-class residents and determines the differences in commuting activity characteristics and influence factors between middle-class and ordinary residents. Policy suggestions to improve urban planning and urban management are also proposed.展开更多
文摘The effect of a-mercapto-β-(2-furyl) acrylic acid (MFA, 200 mg/kg, oral) administered 30 min or 24 h post cadmium (1 mg/kg, i.p.) exposure on cadmium toxicity, was investigated in rats. The Cd induced hepatic metallothionein was reduced by MFA treatment parallel to the depletion of hepatic Cd. However, in renal tissue,MFA caused only redistribution of metal from the paniculate to the soluble fraction. Hepatic and renal Zn and renal Cu were significantly increased on Cd exposure. MFA therapy, however, lowered the hepatic Zn and increased the renal Cu levels. The action of MFA appears to be via metal chelation rather than by MT induction.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFB0400200
文摘We investigate the influence of A1 preflow time on surface morphology and quality of AIN and GaN. The AIN and GaN layers are grown on a Si （111） substrate by metal organic chemical vapor deposition. Scanning electron microscopy, atomic force microscopy, x-ray diffraction and optical microscopy are used for analysis. Consequently, we find significant differences in the epitaxial properties of AlN buffer and the GaN layer, which are dependent on the AI preflow time. A1 preflow layers act as nucleation sites in the case of AiN growth. Compact and uniform AIN nucleation sites are observed with optimizing A1 preflow at an early nucleation stage, which will lead to a smooth AIN surface. Trenches and AlN grain clusters appear on the AIN surface while meltoback etching occurs on the GaN surface with excessive A1 preflow. The GaN quality variation keeps a similar trend with the AIN quality, which is influenced by AI preflow. With an optimized duration orAl preflow, crystal quality and surface morphology of AIN and GaN could be improved.
基金Under the auspices of National Natural Science Foundation of China(No.41271182)
文摘The middle class in metropolitan Chinese cities has become an important social group. With the rapid development of urbanization and constant advancement of suburbanization, the middle class has increasingly come to influence city traffic. Research into middle-class commuting activities thus has practical significance for improving traffic congestion and reducing the commuting burden in metropolitan cities. Based on a dataset formed by 816 completed surveys, this paper analyzes the commuting mode, time and distance of middle-class residents in Guangzhou City using the descriptive statistical method. The results indicate that private cars are the main commuting mode, followed by public transport. Meanwhile, middle-class residents mainly undertake medium-short time and medium-short distance commuting. The study subsequently uses multilevel logistic regression and multiple linear regression models to analyze the factors that influence commuting mode choice, time and distance. The gender, age, number of family cars, housing source and jobs-housing balance are the most important factors influencing commuting mode choice; housing, population density, jobs-housing balance and commuting mode significantly affect commuting time; and transport accessibility, jobs-housing balance and commuting mode are the notable factors affecting commuting distance. Finally, this paper analyzes what is affecting the commuting activities of middle-class residents and determines the differences in commuting activity characteristics and influence factors between middle-class and ordinary residents. Policy suggestions to improve urban planning and urban management are also proposed.
