A chemoreduction-purge-and-trap gas chromatographic method has been developed for the deter-mination of trace dimethylsulfoxide （DMSO） in seawater. In the analysis procedure, DMSO was first reduced to dimethylsufide...A chemoreduction-purge-and-trap gas chromatographic method has been developed for the deter-mination of trace dimethylsulfoxide （DMSO） in seawater. In the analysis procedure, DMSO was first reduced to dimethylsufide （DMS） by sodium borohydride and then the produced DMS was analyzed using the purge-and-trap technique coupled with gas chromatographic separation and flame photometric detection. Under the optimum conditions, 97% DMSO was reduced in the standard solution samples with a standard deviation of 5% （n=5）. The detection limit of DMSO was 2.7 pmol of sulfur, corresponding to a concentration of 0.75 nmol/L for a 40 ml sample. This method was applied to determine the dissolved DMSO （DMSOd） and particulate DMSO （DMSOp） con- centrations in the surface seawater of the Jiaozhou Bay, and the results showed that the DMSOd and DMSOp concentrations varied from 16.8 to 921.1 nmol/L （mean：165.2 nmol/L） and from 8.0 to 162.4 nmol/L （mean： 57.7 nmol/L）, respectively. The high concentrations of DMSOp were generally found in productive regions. Consequently, a significant correlation was found between the concentrations of DMSOp and chlorophyll a, suggesting that phytoplankton biomass might play an important role in controlling the distribution of DMSOp in the bay. Moreover, in the study area, the concentrations of DMSOd were significantly correlated with the levels of DMS, implying that the production of DMSOd is mainly via photochemical and biological oxidation of DMS.展开更多
A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. ...A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. Detection limit of 2.5 pmol of DMS in 25 mL sample, corresponding to 0.10 nmol/L, was achieved. Recoveries for dimethyl sulfur compounds were in the range of 68.6- 78.3%. The relative standard deviations （R.S.D.s） for DMS, DMSP and DMSO determination were 3.0, 5.4 and 7.4%, respectively.展开更多
Background Vorapaxar reduces cardiovascular death, myocardial infarction （MI）, or stroke in patients with previous MI while increasing bleeding. Patients with diabetes mellitus （DM） are at high risk of recurrent t...Background Vorapaxar reduces cardiovascular death, myocardial infarction （MI）, or stroke in patients with previous MI while increasing bleeding. Patients with diabetes mellitus （DM） are at high risk of recurrent thrombotic events despite standard therapy and may derive particular benefit from antithrombotic therapies. The Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events-TIMI 50 trial was a randomized, double-blind, placebo-controlled trial of vorapaxar in patients with stable atherosclerosis.展开更多
基金The National Natural Science Foundation of China under contract Nos 41030858 and 40525017the Changjiang Scholars Program,Ministry of Education of China+1 种基金the National"973"Project under contract No.2010CB428904the"Taishan Scholar"Special Research Fund of Shandong Province,China
文摘A chemoreduction-purge-and-trap gas chromatographic method has been developed for the deter-mination of trace dimethylsulfoxide （DMSO） in seawater. In the analysis procedure, DMSO was first reduced to dimethylsufide （DMS） by sodium borohydride and then the produced DMS was analyzed using the purge-and-trap technique coupled with gas chromatographic separation and flame photometric detection. Under the optimum conditions, 97% DMSO was reduced in the standard solution samples with a standard deviation of 5% （n=5）. The detection limit of DMSO was 2.7 pmol of sulfur, corresponding to a concentration of 0.75 nmol/L for a 40 ml sample. This method was applied to determine the dissolved DMSO （DMSOd） and particulate DMSO （DMSOp） con- centrations in the surface seawater of the Jiaozhou Bay, and the results showed that the DMSOd and DMSOp concentrations varied from 16.8 to 921.1 nmol/L （mean：165.2 nmol/L） and from 8.0 to 162.4 nmol/L （mean： 57.7 nmol/L）, respectively. The high concentrations of DMSOp were generally found in productive regions. Consequently, a significant correlation was found between the concentrations of DMSOp and chlorophyll a, suggesting that phytoplankton biomass might play an important role in controlling the distribution of DMSOp in the bay. Moreover, in the study area, the concentrations of DMSOd were significantly correlated with the levels of DMS, implying that the production of DMSOd is mainly via photochemical and biological oxidation of DMS.
文摘A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. Detection limit of 2.5 pmol of DMS in 25 mL sample, corresponding to 0.10 nmol/L, was achieved. Recoveries for dimethyl sulfur compounds were in the range of 68.6- 78.3%. The relative standard deviations （R.S.D.s） for DMS, DMSP and DMSO determination were 3.0, 5.4 and 7.4%, respectively.
文摘Background Vorapaxar reduces cardiovascular death, myocardial infarction （MI）, or stroke in patients with previous MI while increasing bleeding. Patients with diabetes mellitus （DM） are at high risk of recurrent thrombotic events despite standard therapy and may derive particular benefit from antithrombotic therapies. The Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events-TIMI 50 trial was a randomized, double-blind, placebo-controlled trial of vorapaxar in patients with stable atherosclerosis.
