Soil samples from 4 defined city zones of Nanjing were randomly collected at 0-5 cm and 5-20 cm intervals and size fractions of soil particles were separated from undisturbed bulk soils by low energy dispersion proced...Soil samples from 4 defined city zones of Nanjing were randomly collected at 0-5 cm and 5-20 cm intervals and size fractions of soil particles were separated from undisturbed bulk soils by low energy dispersion procedure. The total contents of Cu and Pb in the different particle size fractions of the urban soils were analyzed by HNO3-HF-HClO4 digestion and flame atomic absorption spectrophotometer determination. The total content of Cu and Pb in soil particle size fractions varied with their size and with city zones as well. Both the content and variation with the size fractions of Pb was bigger than of Cu supporting our previous finding that there was Pb pollution to different degrees in the urban soils although the two elements were generally enriched in clay-sized fraction. Contaminated Pb tended to be preferentially enriched in the size fraction of 2000-250 μm and clay-sized fraction. While the size fractions of the soils from newly developed and preserved area contained smaller amount of Cu and Pb, the partitioning of them in coarse and fine particle size fractions were insignificant compared to that from inner residence and commercial area. The very high Pb level over 150 mg/kg of the fine particle fractions from the soils of the inner city could be a cause of high blood Pb level reported of children from the city as acute exposure to Pb of fine particles of the urban soil might occur by soil ingestion and inhalation by young children. Thus, much attention should be paid to the partitioning of toxic metals in fine soil particles of the urban soils and countermeasures against high health risk of Pb exposure by soil ingestion and dust inhalation should be practiced against the health problem of blood Pb for young children from the cities.展开更多
空中电场大地电磁法(Air electric field electromagnetic method,AEMT)是用电容传感器和磁场传感器观测电磁场在地表空气中的分布情况,研究地下地质结构的一种方法。介绍了AEMT的测量原理,以及在铀尾矿库监测中的应用,其结果较好反映...空中电场大地电磁法(Air electric field electromagnetic method,AEMT)是用电容传感器和磁场传感器观测电磁场在地表空气中的分布情况,研究地下地质结构的一种方法。介绍了AEMT的测量原理,以及在铀尾矿库监测中的应用,其结果较好反映了尾矿库尾矿的埋藏情况,为铀尾矿库的安全运行提供了有效依据。展开更多
Natural gas should be heated and throttled for the purpose of purification and transportation at the first gas production factory of the Changqing field. The safe use and heat-transfer efficiency of a heating-furnace ...Natural gas should be heated and throttled for the purpose of purification and transportation at the first gas production factory of the Changqing field. The safe use and heat-transfer efficiency of a heating-furnace affect the safe and smooth production of natural gas directly. At gas collecting stations now, no measures of anticorrosion have been adopted in heating furnaces which erode and scale badly. In order to solve the corrosive problem of heating-furnaces, prolong operating life of heating-furnaces, assure safe and smooth production of natural gas, the mechanism and influencing factors of corrosion of the heating-furnace were analyzed and some corresponding measures were brought forward based on a field investigation of usage behavior and present operational status of heating-furnaces at the first gas production factory. The results show that the corrosive ion and soluble CO2 and O2 in water erode metal badly at the condition of being heated. Corrosion of a heating-furnace are mostly oxygen corrosion, corrosive ion corrosion, acid corrosion, iron encrustation corrosion, dry and wet interface corrosion, caustic corrosion, etc; The influencing factors of corrosion mainly include soluble O2 and CO2 in water, pH value, heat loading, corrosive ion, soluble solid （salinity） and non-flowing character of water, etc.展开更多
空中电场大地电磁法(Air Electric Field Magneto-Telluric method,简称AEMT),其基本的原理是,通过电容传感器测量近地表空中三个分量的交变电场,用磁棒观测交变磁场,再将所测电场和磁场转化为阻抗,通过对阻抗的解释,达到查明地下地质...空中电场大地电磁法(Air Electric Field Magneto-Telluric method,简称AEMT),其基本的原理是,通过电容传感器测量近地表空中三个分量的交变电场,用磁棒观测交变磁场,再将所测电场和磁场转化为阻抗,通过对阻抗的解释,达到查明地下地质体的分布特征的目的.本文对AEMT基本原理进行较详细的论述,证明了电容传感器代替接电极原理的基本公式.分析了空气中垂直电场的来源,在介绍地面低频电磁波近似边界条件的基础上,导出了AEMT测量垂直电场分量时视电阻率的计算公式,并计算了一维情况下二层、三层地电模型AEMT视电阻率曲线.介绍了应用实例,最后讨论AEMT方法的技术特点.展开更多
Background Target-controlled infusion （TCI） has been recently developed and successfully implemented in clinical practice. This study was conducted to determine the pharmacokinetics of TCI administered sufentanil in...Background Target-controlled infusion （TCI） has been recently developed and successfully implemented in clinical practice. This study was conducted to determine the pharmacokinetics of TCI administered sufentanil in Chinese surgical patients. Methods The pharmacokinetics of sufentanil was investigated in 12 adult patients, aged 23-76 years, scheduled for prolonged surgery under general anesthesia. Anesthetic induction was carried out with propofol, rocuronium and TCI administered sufentanil aiming for target effect-site concentration of sufentanil 4 or 6 ng/ml. Sufentanil TCI lasted for 30 minutes. Frequent arterial blood samples （1.5 ml） were drawn during and up to 24 hours after sufentanil TCI. Plasma sufentanil concentrations were measured by liquid chromatography-tandem mass spectrometry; limit of sensitivity of mass spectrometry was 5 pg/ml. The data were analyzed with the nonlinear mixed-effect model program. Results The pharmacokinetics of TCI administered sufentanil were optimally described by a three-compartment model with the following parameters： the central volume of distribution （V1） = 5.4 L, the volume of distribution at steady-state （Vdss） = 195.4 L, systemic clearance （CI1） = 1.10 L/min, and elimination half-life （t1/2 Y） = 271.8 minutes. Both age and gender affected the pharmacokinetic parameters. The rapid distribution clearance （012） was negatively correlated with patient age, and the volume of slowly equilibrating compartment （V3） was positively correlated with age. The Cl2 and the volume of rapidly equilibrating compartment （V2） were influenced by gender with male patients showing higher values of Cl2 and V2 than female patients. There was no relationship of body weight, lean body mass, plasma albumin, or target effect-site concentration of sufentanil with any of the pharmacokinetic parameters studied. Conclusions The pharmacokinetics of TCI administered sufentanil in Chinese patients can be adequately described by a three-compartment model. Pharmacokinetics adjusted to the individual patient should improve the accuracy of TCI systems.展开更多
Background Sufentanil target controlled infusion （TCI） provides stable analgesia, better hemodynamic control than a bolus injection of intravenous anesthetics, anticipated recovery and improved quality of anesthesia...Background Sufentanil target controlled infusion （TCI） provides stable analgesia, better hemodynamic control than a bolus injection of intravenous anesthetics, anticipated recovery and improved quality of anesthesia during perioperative period. This study evaluated the accuracy and feasibility of TCI system for sufentanil at high concentrations in Chinese surgical patients. Methods Twelve low risk adult patients undergoing elective surgery under general anesthesia were included in this study. Sufentanil was administered with a specific TCI system incorporating the population pharmacokinetic data of sufentanil previously reported, using a target effect-site concentration of sufentanil 4 or 6 ng/ml. Sufentanil TCI duration was 30 minutes. Frequent arterial blood samples were taken during and up to 24 hours after sufentanil TCI for determination of plasma sufentanil concentrations by liquid chromatography-mass spectrometry/mass spectrometry. The changes of circulatory system function during the procedure, recovery profile and adverse effects were recorded. Measured plasma sufentanil concentrations were compared with the values predicted by the TCI system. The bias （median performance error, MDPE）, precision （median absolute performance error, MDAPE） and wobble （variability of performance error） of the sufentanil TCI system were determined. Results All patients had stable cardiovascular variables during induction and maintenance of anesthesia. Time to eye opening and extubation were （5.6±1.7） minutes when TCI set to 4 ng/ml and （7.2±2.3） minutes when set to 6 ng/ml. There was no episode of agitation, muscle rigidity or intraoperative awareness. The bias （MDPE）, precision （MDAPE） and wobble of the sufentanil TCI system were -3.7%, 18.9% and 19.6% respectively during TCI, and the MDPE, MDAPE and wobble were -29.1%, 31.7% and 15.0% respectively after TCI （up to 8 hours）. Conclusions The TCI system programmed for sufentanil at 4 or 6 ng/ml was considered acceptable for clinical use in low risk Chinese surgical patients. But the relatively larger MDPE and MDAPE after TCI suggest improvements of the Dharmacokinetic model are needed.展开更多
Background Sufentanil is a suitable choice for target-controlled infusion （TCI） because of its shorter context-sensitive half-time. The current study was to estimate the pharmacokinetics of sufentanil TCI in Chinese...Background Sufentanil is a suitable choice for target-controlled infusion （TCI） because of its shorter context-sensitive half-time. The current study was to estimate the pharmacokinetics of sufentanil TCI in Chinese patients using the two-stage analysis. Methods Twelve adult patients with American Society of Anesthesiologists （ASA） physical status I or II undergoing elective surgery under general anesthesia were included. Anesthesia was induced with propofol, rocuronium and sufentanil administered by TCI lasting for 30 minutes, with target effect-site concentration of sufentanil 4 or 6 ng/ml. Frequent arterial blood samples （1.5 ml） were taken during and up to 24 hours after sufentanil TCI. Before the end of surgery, another arterial blood sample （1.0 ml） was drawn for the blood-gas analysis. Plasma sufentanil concentrations were determined by liquid chromatography-tandem mass spectrometry （limit of quantitation was 5 pg/ml）. The data were analyzed with the two-stage approach, linear regression and correlation analysis. Results The pharmacokinetics of sufentanil TCI were adequately described by a three-compartment model. The variables were derived as follows： the volume of central compartment （V1） was 5.4 L, volume of distribution at steady-state （Vdss） was 222.6 L, metabolic clearance （CI1） was 0.84 L/min and elimination half-life （t~/2y） was 389 minutes. Patients＇ age, gender and PaCO2 correlated significantly with the pharmacokinetic parameters. The Vdss, volume of slowly equilibrating compartment （V3） and t1/2 y increased, and rapid distribution clearance （012） decreased with increasing patient age. Male patients had larger values of Vdss, volume of rapidly equilibrating compartment （V2） and V3 than female patients. The Vdss and V3 increased with higher PaCO2 values. There were no significant correlations between the pharmacokinetic variables and body weight, height, lean body mass, plasma albumin, sufentanil dose, duration of surgery, pH or base excess of blood （BE-B）. Conclusions The pharmacokinetics of sufentanil TCI in Chinese patients can be optimally described by a three-compartment model. The pharmacokinetic analysis technique may affect the pharmacokinetic parameters and correlations.展开更多
基金The Key Research Project of Ministry of Education of China(No. 2002012)
文摘Soil samples from 4 defined city zones of Nanjing were randomly collected at 0-5 cm and 5-20 cm intervals and size fractions of soil particles were separated from undisturbed bulk soils by low energy dispersion procedure. The total contents of Cu and Pb in the different particle size fractions of the urban soils were analyzed by HNO3-HF-HClO4 digestion and flame atomic absorption spectrophotometer determination. The total content of Cu and Pb in soil particle size fractions varied with their size and with city zones as well. Both the content and variation with the size fractions of Pb was bigger than of Cu supporting our previous finding that there was Pb pollution to different degrees in the urban soils although the two elements were generally enriched in clay-sized fraction. Contaminated Pb tended to be preferentially enriched in the size fraction of 2000-250 μm and clay-sized fraction. While the size fractions of the soils from newly developed and preserved area contained smaller amount of Cu and Pb, the partitioning of them in coarse and fine particle size fractions were insignificant compared to that from inner residence and commercial area. The very high Pb level over 150 mg/kg of the fine particle fractions from the soils of the inner city could be a cause of high blood Pb level reported of children from the city as acute exposure to Pb of fine particles of the urban soil might occur by soil ingestion and inhalation by young children. Thus, much attention should be paid to the partitioning of toxic metals in fine soil particles of the urban soils and countermeasures against high health risk of Pb exposure by soil ingestion and dust inhalation should be practiced against the health problem of blood Pb for young children from the cities.
文摘空中电场大地电磁法(Air electric field electromagnetic method,AEMT)是用电容传感器和磁场传感器观测电磁场在地表空气中的分布情况,研究地下地质结构的一种方法。介绍了AEMT的测量原理,以及在铀尾矿库监测中的应用,其结果较好反映了尾矿库尾矿的埋藏情况,为铀尾矿库的安全运行提供了有效依据。
文摘Natural gas should be heated and throttled for the purpose of purification and transportation at the first gas production factory of the Changqing field. The safe use and heat-transfer efficiency of a heating-furnace affect the safe and smooth production of natural gas directly. At gas collecting stations now, no measures of anticorrosion have been adopted in heating furnaces which erode and scale badly. In order to solve the corrosive problem of heating-furnaces, prolong operating life of heating-furnaces, assure safe and smooth production of natural gas, the mechanism and influencing factors of corrosion of the heating-furnace were analyzed and some corresponding measures were brought forward based on a field investigation of usage behavior and present operational status of heating-furnaces at the first gas production factory. The results show that the corrosive ion and soluble CO2 and O2 in water erode metal badly at the condition of being heated. Corrosion of a heating-furnace are mostly oxygen corrosion, corrosive ion corrosion, acid corrosion, iron encrustation corrosion, dry and wet interface corrosion, caustic corrosion, etc; The influencing factors of corrosion mainly include soluble O2 and CO2 in water, pH value, heat loading, corrosive ion, soluble solid （salinity） and non-flowing character of water, etc.
文摘空中电场大地电磁法(Air Electric Field Magneto-Telluric method,简称AEMT),其基本的原理是,通过电容传感器测量近地表空中三个分量的交变电场,用磁棒观测交变磁场,再将所测电场和磁场转化为阻抗,通过对阻抗的解释,达到查明地下地质体的分布特征的目的.本文对AEMT基本原理进行较详细的论述,证明了电容传感器代替接电极原理的基本公式.分析了空气中垂直电场的来源,在介绍地面低频电磁波近似边界条件的基础上,导出了AEMT测量垂直电场分量时视电阻率的计算公式,并计算了一维情况下二层、三层地电模型AEMT视电阻率曲线.介绍了应用实例,最后讨论AEMT方法的技术特点.
文摘Background Target-controlled infusion （TCI） has been recently developed and successfully implemented in clinical practice. This study was conducted to determine the pharmacokinetics of TCI administered sufentanil in Chinese surgical patients. Methods The pharmacokinetics of sufentanil was investigated in 12 adult patients, aged 23-76 years, scheduled for prolonged surgery under general anesthesia. Anesthetic induction was carried out with propofol, rocuronium and TCI administered sufentanil aiming for target effect-site concentration of sufentanil 4 or 6 ng/ml. Sufentanil TCI lasted for 30 minutes. Frequent arterial blood samples （1.5 ml） were drawn during and up to 24 hours after sufentanil TCI. Plasma sufentanil concentrations were measured by liquid chromatography-tandem mass spectrometry; limit of sensitivity of mass spectrometry was 5 pg/ml. The data were analyzed with the nonlinear mixed-effect model program. Results The pharmacokinetics of TCI administered sufentanil were optimally described by a three-compartment model with the following parameters： the central volume of distribution （V1） = 5.4 L, the volume of distribution at steady-state （Vdss） = 195.4 L, systemic clearance （CI1） = 1.10 L/min, and elimination half-life （t1/2 Y） = 271.8 minutes. Both age and gender affected the pharmacokinetic parameters. The rapid distribution clearance （012） was negatively correlated with patient age, and the volume of slowly equilibrating compartment （V3） was positively correlated with age. The Cl2 and the volume of rapidly equilibrating compartment （V2） were influenced by gender with male patients showing higher values of Cl2 and V2 than female patients. There was no relationship of body weight, lean body mass, plasma albumin, or target effect-site concentration of sufentanil with any of the pharmacokinetic parameters studied. Conclusions The pharmacokinetics of TCI administered sufentanil in Chinese patients can be adequately described by a three-compartment model. Pharmacokinetics adjusted to the individual patient should improve the accuracy of TCI systems.
文摘Background Sufentanil target controlled infusion （TCI） provides stable analgesia, better hemodynamic control than a bolus injection of intravenous anesthetics, anticipated recovery and improved quality of anesthesia during perioperative period. This study evaluated the accuracy and feasibility of TCI system for sufentanil at high concentrations in Chinese surgical patients. Methods Twelve low risk adult patients undergoing elective surgery under general anesthesia were included in this study. Sufentanil was administered with a specific TCI system incorporating the population pharmacokinetic data of sufentanil previously reported, using a target effect-site concentration of sufentanil 4 or 6 ng/ml. Sufentanil TCI duration was 30 minutes. Frequent arterial blood samples were taken during and up to 24 hours after sufentanil TCI for determination of plasma sufentanil concentrations by liquid chromatography-mass spectrometry/mass spectrometry. The changes of circulatory system function during the procedure, recovery profile and adverse effects were recorded. Measured plasma sufentanil concentrations were compared with the values predicted by the TCI system. The bias （median performance error, MDPE）, precision （median absolute performance error, MDAPE） and wobble （variability of performance error） of the sufentanil TCI system were determined. Results All patients had stable cardiovascular variables during induction and maintenance of anesthesia. Time to eye opening and extubation were （5.6±1.7） minutes when TCI set to 4 ng/ml and （7.2±2.3） minutes when set to 6 ng/ml. There was no episode of agitation, muscle rigidity or intraoperative awareness. The bias （MDPE）, precision （MDAPE） and wobble of the sufentanil TCI system were -3.7%, 18.9% and 19.6% respectively during TCI, and the MDPE, MDAPE and wobble were -29.1%, 31.7% and 15.0% respectively after TCI （up to 8 hours）. Conclusions The TCI system programmed for sufentanil at 4 or 6 ng/ml was considered acceptable for clinical use in low risk Chinese surgical patients. But the relatively larger MDPE and MDAPE after TCI suggest improvements of the Dharmacokinetic model are needed.
文摘Background Sufentanil is a suitable choice for target-controlled infusion （TCI） because of its shorter context-sensitive half-time. The current study was to estimate the pharmacokinetics of sufentanil TCI in Chinese patients using the two-stage analysis. Methods Twelve adult patients with American Society of Anesthesiologists （ASA） physical status I or II undergoing elective surgery under general anesthesia were included. Anesthesia was induced with propofol, rocuronium and sufentanil administered by TCI lasting for 30 minutes, with target effect-site concentration of sufentanil 4 or 6 ng/ml. Frequent arterial blood samples （1.5 ml） were taken during and up to 24 hours after sufentanil TCI. Before the end of surgery, another arterial blood sample （1.0 ml） was drawn for the blood-gas analysis. Plasma sufentanil concentrations were determined by liquid chromatography-tandem mass spectrometry （limit of quantitation was 5 pg/ml）. The data were analyzed with the two-stage approach, linear regression and correlation analysis. Results The pharmacokinetics of sufentanil TCI were adequately described by a three-compartment model. The variables were derived as follows： the volume of central compartment （V1） was 5.4 L, volume of distribution at steady-state （Vdss） was 222.6 L, metabolic clearance （CI1） was 0.84 L/min and elimination half-life （t~/2y） was 389 minutes. Patients＇ age, gender and PaCO2 correlated significantly with the pharmacokinetic parameters. The Vdss, volume of slowly equilibrating compartment （V3） and t1/2 y increased, and rapid distribution clearance （012） decreased with increasing patient age. Male patients had larger values of Vdss, volume of rapidly equilibrating compartment （V2） and V3 than female patients. The Vdss and V3 increased with higher PaCO2 values. There were no significant correlations between the pharmacokinetic variables and body weight, height, lean body mass, plasma albumin, sufentanil dose, duration of surgery, pH or base excess of blood （BE-B）. Conclusions The pharmacokinetics of sufentanil TCI in Chinese patients can be optimally described by a three-compartment model. The pharmacokinetic analysis technique may affect the pharmacokinetic parameters and correlations.
