Soil column liquid chromatography (SCLC) was developed to determine soil organic carbon adsorption coefficients (E-oc) for chemicals. The uptake by soil of pesticides from water can be conveniently calculated from the...Soil column liquid chromatography (SCLC) was developed to determine soil organic carbon adsorption coefficients (E-oc) for chemicals. The uptake by soil of pesticides from water can be conveniently calculated from the related breakthrough curves (BTC). The nine pesticides chosen for determination in this study are soluble ones, with their water solubility ranging from 62 mg/L to Z mg/L. In comparing with existing methods of K-oc, SCLC possesses rapid, online and accurate characteristics.展开更多
To evaluate the subchronic and chronic toxicity of Fuyanxiao capsules,Sprague-Dawley(SD)rats were used in toxicity studies.In the subchronic toxicity study,50 female rats were randomly divided into a high-dose group(5...To evaluate the subchronic and chronic toxicity of Fuyanxiao capsules,Sprague-Dawley(SD)rats were used in toxicity studies.In the subchronic toxicity study,50 female rats were randomly divided into a high-dose group(5.4g/kg/day)and a control group,with 15 rats in each,and medium(2.7g/kg/day)and low(1.35g/kg/day)dose groups,with 10 rats in each.The test substance was administered orally(mixed with feed,twice daily)for 90 consecutive days.In the chronic toxicity study,40 female rats were randomly divided into high,medium,and low dose groups and a control group,with 10 rats in each.The test substance was administered orally in the same manner for 180 consecutive days.Clinical signs,body weight,and food consumption were observed and recorded daily.At the end of the terminal phase(the first 10 rats from each group,1 day after the last dose)and the recovery phase(the last 5 rats from the control group and the high-dose group,observed for an additional 28 days after the last dose),blood and urine samples,as well as organs,were collected.Organ coefficients were calculated,and various hematological and urinary indicators were detected,followed by pathological analysis.The results showed that there were no significant differences in body weight,food consumption,or organ coefficients between any of the dose groups and the control group in both subchronic and chronic toxicity studies(P>0.05).Histopathological examination revealed no lesions,suggesting no tissue or organ damage in any of the dose groups.The rats exhibited good mental status,and hematological and urinary physiological indicators were within normal ranges,indicating stable liver and kidney function,hematopoietic system of the bone marrow,and internal environment in all dose groups.Therefore,Fuyanxiao capsule has no obvious subchronic or chronic toxicity in SD rats,and it is safe and reliable to use at reasonable dosage in clinical practice.展开更多
Quantum chemistry parameters of 22 fluorobenzenes were computed at six levels using Hartree-Fock and DFT methods. Based on the experimental data of n-octanol/water partition coefficient （lgKow）, a three-parameter （...Quantum chemistry parameters of 22 fluorobenzenes were computed at six levels using Hartree-Fock and DFT methods. Based on the experimental data of n-octanol/water partition coefficient （lgKow）, a three-parameter （dipole moments （μ）, zero point energy （ZPE） and free energy （G°）） quantitative correlation equation that can predict IgKow was developed using structural and thermodynamic parameters as theoretical descriptors. Similarly, based on experimental data of soil organic carbon sorption coefficient （lgKoc）, the other three-parameter （the most negative atomic net charge of molecule （q^-）, dipole moments （μ） and molecular volume （Vi）） quantitative correlation equation that can predict lgKoc was given. Quantitative correlation equations based on B3LYP/6- 311 G^＊＊ calculation were validated by VIF （variance inflation factors） and t-test and used to predict IgKow and lgKoc of a series of compounds. The result showed that the correlation and prediction ability of lgKoc equations based on three levels of HF/STO-3G, B3LYP/6-31 G^＊ and B3LYP/6- 311G^＊＊ are all more advantageous than those based on AMI.展开更多
Acid-catalyzed heterogeneous oxidation with hydrogen peroxide（H2O2） has been suggested to be a potential pathway for secondary organic aerosol（SOA） formation from isoprene and its oxidation products. However, know...Acid-catalyzed heterogeneous oxidation with hydrogen peroxide（H2O2） has been suggested to be a potential pathway for secondary organic aerosol（SOA） formation from isoprene and its oxidation products. However, knowledge of the chemical mechanism and kinetics for this process is still incomplete. 3-Methyl-2-buten-1-ol（MBO321）, an aliphatic alcohol structurally similar to isoprene, is emitted by pine forests and widely used in the manufacturing industries. Herein the uptake of MBO321 into H2SO4-H2O2mixed solution was investigated using a flow-tube reactor coupled to a mass spectrometer. The reactive uptake coefficients（γ） were acquired for the first time and were found to increase rapidly with increasing acid concentration. Corresponding aqueous-phase reactions were performed to further study the mechanism of this acid-catalyzed reaction. MBO321 could convert to 2-methyl-3-buten-2-ol（MBO232） and yield isoprene in acidic media. Organic hydroperoxides（ROOHs） were found to be generated through the acid-catalyzed route,which could undergo a rearrangement reaction and result in the formation of acetone and acetaldehyde. Organosulfates, which have been proposed to be SOA tracer compounds in the atmosphere, were also produced during the oxidation process. These results suggest that the heterogeneous acid-catalyzed reaction of MBO321 with H2O2 may contribute to SOA mass under certain atmospheric conditions.展开更多
On the basis of Jacobson's free length theory and the theory of pressure coefficient and temperature coefficient of free length in liquids, the relationship between the pressure coefficient of ultrasonic velocity...On the basis of Jacobson's free length theory and the theory of pressure coefficient and temperature coefficient of free length in liquids, the relationship between the pressure coefficient of ultrasonic velocity and the pressure coefficient of free length, and the relationship between the temperature coefficient of ultrasonic velocity and the temperature coefficient of free length were studied. Relevant equations were given, and the pressure coefficient and temperature coefficient of ultrasonic velocity were calculated, which are in agreement with the measured values.展开更多
基金Bayer AG and Chinese Academy of Agricultural Sciences for kindly supplying the pesticides.
文摘Soil column liquid chromatography (SCLC) was developed to determine soil organic carbon adsorption coefficients (E-oc) for chemicals. The uptake by soil of pesticides from water can be conveniently calculated from the related breakthrough curves (BTC). The nine pesticides chosen for determination in this study are soluble ones, with their water solubility ranging from 62 mg/L to Z mg/L. In comparing with existing methods of K-oc, SCLC possesses rapid, online and accurate characteristics.
文摘To evaluate the subchronic and chronic toxicity of Fuyanxiao capsules,Sprague-Dawley(SD)rats were used in toxicity studies.In the subchronic toxicity study,50 female rats were randomly divided into a high-dose group(5.4g/kg/day)and a control group,with 15 rats in each,and medium(2.7g/kg/day)and low(1.35g/kg/day)dose groups,with 10 rats in each.The test substance was administered orally(mixed with feed,twice daily)for 90 consecutive days.In the chronic toxicity study,40 female rats were randomly divided into high,medium,and low dose groups and a control group,with 10 rats in each.The test substance was administered orally in the same manner for 180 consecutive days.Clinical signs,body weight,and food consumption were observed and recorded daily.At the end of the terminal phase(the first 10 rats from each group,1 day after the last dose)and the recovery phase(the last 5 rats from the control group and the high-dose group,observed for an additional 28 days after the last dose),blood and urine samples,as well as organs,were collected.Organ coefficients were calculated,and various hematological and urinary indicators were detected,followed by pathological analysis.The results showed that there were no significant differences in body weight,food consumption,or organ coefficients between any of the dose groups and the control group in both subchronic and chronic toxicity studies(P>0.05).Histopathological examination revealed no lesions,suggesting no tissue or organ damage in any of the dose groups.The rats exhibited good mental status,and hematological and urinary physiological indicators were within normal ranges,indicating stable liver and kidney function,hematopoietic system of the bone marrow,and internal environment in all dose groups.Therefore,Fuyanxiao capsule has no obvious subchronic or chronic toxicity in SD rats,and it is safe and reliable to use at reasonable dosage in clinical practice.
基金Project supported by the Chinese Postdoctoral Science Foundation (No. 2003033486) and the National Natural Science Foundation of China (20477018)
文摘Quantum chemistry parameters of 22 fluorobenzenes were computed at six levels using Hartree-Fock and DFT methods. Based on the experimental data of n-octanol/water partition coefficient （lgKow）, a three-parameter （dipole moments （μ）, zero point energy （ZPE） and free energy （G°）） quantitative correlation equation that can predict IgKow was developed using structural and thermodynamic parameters as theoretical descriptors. Similarly, based on experimental data of soil organic carbon sorption coefficient （lgKoc）, the other three-parameter （the most negative atomic net charge of molecule （q^-）, dipole moments （μ） and molecular volume （Vi）） quantitative correlation equation that can predict lgKoc was given. Quantitative correlation equations based on B3LYP/6- 311 G^＊＊ calculation were validated by VIF （variance inflation factors） and t-test and used to predict IgKow and lgKoc of a series of compounds. The result showed that the correlation and prediction ability of lgKoc equations based on three levels of HF/STO-3G, B3LYP/6-31 G^＊ and B3LYP/6- 311G^＊＊ are all more advantageous than those based on AMI.
基金project was supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (No. XDB05010400)the National Basic Research Program (973) of Ministry of Science and Technology of China (No. 2011CB403401)the National Natural Science Foundation of China (Major Program: 21190052) (Nos. 40925016, 41173112)
文摘Acid-catalyzed heterogeneous oxidation with hydrogen peroxide（H2O2） has been suggested to be a potential pathway for secondary organic aerosol（SOA） formation from isoprene and its oxidation products. However, knowledge of the chemical mechanism and kinetics for this process is still incomplete. 3-Methyl-2-buten-1-ol（MBO321）, an aliphatic alcohol structurally similar to isoprene, is emitted by pine forests and widely used in the manufacturing industries. Herein the uptake of MBO321 into H2SO4-H2O2mixed solution was investigated using a flow-tube reactor coupled to a mass spectrometer. The reactive uptake coefficients（γ） were acquired for the first time and were found to increase rapidly with increasing acid concentration. Corresponding aqueous-phase reactions were performed to further study the mechanism of this acid-catalyzed reaction. MBO321 could convert to 2-methyl-3-buten-2-ol（MBO232） and yield isoprene in acidic media. Organic hydroperoxides（ROOHs） were found to be generated through the acid-catalyzed route,which could undergo a rearrangement reaction and result in the formation of acetone and acetaldehyde. Organosulfates, which have been proposed to be SOA tracer compounds in the atmosphere, were also produced during the oxidation process. These results suggest that the heterogeneous acid-catalyzed reaction of MBO321 with H2O2 may contribute to SOA mass under certain atmospheric conditions.
文摘On the basis of Jacobson's free length theory and the theory of pressure coefficient and temperature coefficient of free length in liquids, the relationship between the pressure coefficient of ultrasonic velocity and the pressure coefficient of free length, and the relationship between the temperature coefficient of ultrasonic velocity and the temperature coefficient of free length were studied. Relevant equations were given, and the pressure coefficient and temperature coefficient of ultrasonic velocity were calculated, which are in agreement with the measured values.
