A dual wavelength differential first derivative spectrophotometric method has been developed to standardize the concentration of a saturated aqueous solution of carbon monoxide (CO) as the standard and to identify and...A dual wavelength differential first derivative spectrophotometric method has been developed to standardize the concentration of a saturated aqueous solution of carbon monoxide (CO) as the standard and to identify and to determine CO formed during the microsomal metabolism of xenobiotics in vitro. The method can significantly eliminate the background interference in the assay media and increase the quantitative accuracy and the sensitivity. There is a good linear relationship between CO concentration in the range of 2～10 μmol·L 1 CO and the distance D between the first derivative peak at 415 nm amd valley at 426 nm with r=0.9999(n=5),the regression equation being C (mmol·L 1 )=17.6D 0.4, the detection limit lower than 0.1 μmol·L 1 CO. The average recoveries of CO from the assay system and the sample were 102.1%, RSD=2.9% (n=7) and 79.7%, RSD=6.8% (n=12),respectively. The RSD of within day was 4.4%(n=18),and the RSD of day to day was 6.1%(n=16). By this method, four trihaloanilines and one trihalobenzene were tested, the results showed that only 2,4,5 trifluoroaniline could be converted to CO by the incubation with rat hepatic microsomes, NADPH and oxygen, the ability of phenobarbital or dexamethasone to induce rat hepatic microsomes to catalyze CO formation was 3 or 8 times higher than that of the control.展开更多
Mutagenesis of Lactobacillus casei subsp, rhamnosus Xl-12 after low power microwave irradiation was investigated. Under a microwave power of 400 W and irradiation length of 3 min, a mutated strain W4-3-9 with high-yie...Mutagenesis of Lactobacillus casei subsp, rhamnosus Xl-12 after low power microwave irradiation was investigated. Under a microwave power of 400 W and irradiation length of 3 min, a mutated strain W4-3-9 with high-yield L-lactic acid was obtained by screening. Compared with the starting strain X1-12, the L-lactic acid production of W4-3-9 was increased by 58.0% at a concentration of 115.8 g/L. The strain maintained the capability of producing a high L-lactic acid level after 10 generations. Cell surface morphology and DNA structures of parental and mutated strains were observed by atomic force microscopy （ AFM ）. Amplified fragment length polymorphism （AFLP） analysis suggested the difference in AFLP band pattern between the mutated and non-mutated strains. Sequencing and BLAST analysis revealed that the catalytic site of lactate dehydrogenase （DHL） was changed due to the microwave induced mutation.展开更多
The authors present a new design of high resolution and wide dynamic range photonic crystal pressure sensor. This sensor is based on two-dimensional photonic crystal with square array of silicon rods surrounded by air...The authors present a new design of high resolution and wide dynamic range photonic crystal pressure sensor. This sensor is based on two-dimensional photonic crystal with square array of silicon rods surrounded by air. The sensor consists of a photonic crystal waveguide which is coupled to a photonic crystal nanocavity. The waveguide is configured by removing one row of Si rods and nanocavity is formed by modifying the radius of one Si rod. The sensor is designed for 1300 nm-1400 nm wavelengths. Simulation results show that resonant wavelength of nanocavity is linearly shifted to larger wavelengths by increasing the pressure. The designed sensor has a linear behavior between 0.1 GPa to 10 GPa of applied pressure and 8 nrrdGPa of pressure sensitivity.展开更多
文摘A dual wavelength differential first derivative spectrophotometric method has been developed to standardize the concentration of a saturated aqueous solution of carbon monoxide (CO) as the standard and to identify and to determine CO formed during the microsomal metabolism of xenobiotics in vitro. The method can significantly eliminate the background interference in the assay media and increase the quantitative accuracy and the sensitivity. There is a good linear relationship between CO concentration in the range of 2～10 μmol·L 1 CO and the distance D between the first derivative peak at 415 nm amd valley at 426 nm with r=0.9999(n=5),the regression equation being C (mmol·L 1 )=17.6D 0.4, the detection limit lower than 0.1 μmol·L 1 CO. The average recoveries of CO from the assay system and the sample were 102.1%, RSD=2.9% (n=7) and 79.7%, RSD=6.8% (n=12),respectively. The RSD of within day was 4.4%(n=18),and the RSD of day to day was 6.1%(n=16). By this method, four trihaloanilines and one trihalobenzene were tested, the results showed that only 2,4,5 trifluoroaniline could be converted to CO by the incubation with rat hepatic microsomes, NADPH and oxygen, the ability of phenobarbital or dexamethasone to induce rat hepatic microsomes to catalyze CO formation was 3 or 8 times higher than that of the control.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50778053)
文摘Mutagenesis of Lactobacillus casei subsp, rhamnosus Xl-12 after low power microwave irradiation was investigated. Under a microwave power of 400 W and irradiation length of 3 min, a mutated strain W4-3-9 with high-yield L-lactic acid was obtained by screening. Compared with the starting strain X1-12, the L-lactic acid production of W4-3-9 was increased by 58.0% at a concentration of 115.8 g/L. The strain maintained the capability of producing a high L-lactic acid level after 10 generations. Cell surface morphology and DNA structures of parental and mutated strains were observed by atomic force microscopy （ AFM ）. Amplified fragment length polymorphism （AFLP） analysis suggested the difference in AFLP band pattern between the mutated and non-mutated strains. Sequencing and BLAST analysis revealed that the catalytic site of lactate dehydrogenase （DHL） was changed due to the microwave induced mutation.
文摘The authors present a new design of high resolution and wide dynamic range photonic crystal pressure sensor. This sensor is based on two-dimensional photonic crystal with square array of silicon rods surrounded by air. The sensor consists of a photonic crystal waveguide which is coupled to a photonic crystal nanocavity. The waveguide is configured by removing one row of Si rods and nanocavity is formed by modifying the radius of one Si rod. The sensor is designed for 1300 nm-1400 nm wavelengths. Simulation results show that resonant wavelength of nanocavity is linearly shifted to larger wavelengths by increasing the pressure. The designed sensor has a linear behavior between 0.1 GPa to 10 GPa of applied pressure and 8 nrrdGPa of pressure sensitivity.
