The dissolution mechanism of marmatite in the presence of Cu^(2+)was intensively studied by experiments and density functional theory(DFT) calculations. Leaching experiments showed that Cu^(2+)accelerated marmatite di...The dissolution mechanism of marmatite in the presence of Cu^(2+)was intensively studied by experiments and density functional theory(DFT) calculations. Leaching experiments showed that Cu^(2+)accelerated marmatite dissolution at high temperatures(above 55 ℃), but the trend was reversed at low temperatures(below 45 ℃), which may be because the reaction mechanism between Cu^(2+)and marmatite changed from surface adsorption to bulk substitution with increasing temperature. The substitution reaction caused more zinc atoms in the marmatite crystal lattice to be released and enhanced the electrochemical reactivity, while the adsorption of copper ions at low temperatures would passivate marmatite, thus inhibiting the reaction process. DFT calculations showed that the energy of the substitution reaction was more negative than that of the adsorption reaction at high temperatures, which further verified the proposed mechanism.展开更多
This study aimed to investigate the effects of copper and manganese on hemocyte apoptosis and the antagonism of iron and zinc in Oreochromis niloticus The heavy metal contents in fish blood and feed were determined by...This study aimed to investigate the effects of copper and manganese on hemocyte apoptosis and the antagonism of iron and zinc in Oreochromis niloticus The heavy metal contents in fish blood and feed were determined by atomic absorption spectrophotometry, and the hemocyte apoptosis was determined by flow cytometry. A total of 360 tilapias were selected, and they were divided randomly and evenly into 12 groups. In the challenge groups, the tilapias were fed with con stant-level copper sulfate（0, 200 mg/kg） and manganese sulfate（0, 120 mg/kg）; in the antagonism groups, the tilapias were fed with constant-level zinc sulfate（20320 mg/kg） and iron sulfate（150, 350 mg/kg）. After 20-week aquaculture, the hemocyte apoptosis rates in the copper and manganese groups were significantly increased; with the increased addition levels of iron and zinc, the hemocyte apopto sis rates in the iron and zinc groups were significantly reduced, but they were stil higher than that in the control group. In conclusion, excessive copper and manganese can cause apoptosis in hemocytes of O. niloticus. However, the toxic effects of copper and manganese can be antagonized by iron and zinc.展开更多
The distribution of various fractions of Zn, Fe, Cu and Mn in 15 types of sods in China and its rela-tionship with plant availability were studied. Wactions of various elements were found to have some similarcharacter...The distribution of various fractions of Zn, Fe, Cu and Mn in 15 types of sods in China and its rela-tionship with plant availability were studied. Wactions of various elements were found to have some similarcharacteristic distribution regularities in wirious types of soils, but various soil types derered to varyingdegrees in the distribution of each fraction. Soil physico-chemical properties, such as pH, CEC and thecontents of OM, CaCO_3, free Fe, free Mn and P_2O_5, were signdicantly correlated with the distribution ofelemental fractions, and a significazit correlation also existed between the distribution and plant amilabilityof elemental fractions. Varfous fractions of each element were divided into two groups bed on their plantavailability. The correlation between the distribution of combination fractions aiid plaxit availability indi-cated a significantly or an extremely significantly positive correlation for Group I but a significantly or anextremely significantly negative correlation for Group II. Therefore, the fractions in Group I were primarypools of available nutrients, while those in Group II could hardly provide available nutrients for plants. Descreasing the transformation of corresponding elements into fractions of Group 11 and increasing the storagecapacity of various fractions of Group I were an important direction for regulation and controiling of soilnutrients. However, some Particular soils with too high contents of Zn, Fe, Cu and Mn should be regulatedand controlled adversely展开更多
Samples of 21 soil profiles and 165 top soils from an area of approximate 1.5km^2 on red-earthy hill landscape were collected and analysed.The content of Ca,Mg,K,P,Fe,Mn,Zn and Cu in soils relate with the kind of pare...Samples of 21 soil profiles and 165 top soils from an area of approximate 1.5km^2 on red-earthy hill landscape were collected and analysed.The content of Ca,Mg,K,P,Fe,Mn,Zn and Cu in soils relate with the kind of parent material and the position of topography,however,there is great variation due to the local difference of the form of soil utilization.From the difference in spatial distribution of elements content,it is believed that eight kinds of elements are lost by chemical leaching and physical translocation,meanwhile some are added (such as Ca,P,K,Mg) and some mobilized (such as Fe,Mn,Zn,Cu and P) through cultivation,fertilization and irrigation in the soils on the landscape investigated.The sectional differentiation in abundance or deficiency of elements in top soils on the landscape investigated is distinct,which is important for carrying out agricultural management and reasonable fertilization according to local conditions.展开更多
The five chemical associations of heavy metals have been extracted continuously using the Tessier extracting method. Results show that Cu, Pb, Fe, Zn and Cr in the sediments are mainly distributed in residual fraction...The five chemical associations of heavy metals have been extracted continuously using the Tessier extracting method. Results show that Cu, Pb, Fe, Zn and Cr in the sediments are mainly distributed in residual fraction, while the major chemical association of Mn is carbonates. Carbonate heavy metals are converted into Fe-Mn oxides in autumn. And in the low tidal flat, after carbonates have changed into ionic heavy metals, some of the elements are transported to the overlying water. Cu, Pb, Fe and Mn have good correlations with each other, and Zn, Cr also show their similarity of chemical behavior in the sediments.展开更多
AIM： To investigate the effects of short-term application of low-dose growth hormone on trace element metabolism and blood glucose in surgical patients METHODS： A total of 48 consecutive patients undergoing abdomina...AIM： To investigate the effects of short-term application of low-dose growth hormone on trace element metabolism and blood glucose in surgical patients METHODS： A total of 48 consecutive patients undergoing abdominal operations were randomized to receive either subcutaneous rhGH （0.15 IU/kg） or placebo （menstruum） injections daily for 7 d after surgery. The two groups had similar nutrition intake. Blood, feces, urine and drain samples were collected to measure zincum, cuprum and ferrum as well as glucose levels. Accumulative intake, excretion and balance of zincum, cuprum and ferrum, apparent absorption （AA） and apparent utilization （AU） of zincum, cuprum and ferrum, blood glucose levels and adverse events were estimated. RESULTS： There were no differences in accumulative intake and drain excretion between the two groups. The feces excretion and accumulative excretion of cuprum were lower in the rhGH group （P 〈 0.05）. The urinary excretion of zincum, cuprum and ferrum was all significantly decreased in the rhGH group （P 〈 0.05） and the accumulative balance of zincum, cuprum and ferrum was improved compared with the placebo group （P 〈 0.05）. AA of cuprum in the rhGH group was almost twice as much as the placebo group （P 〈 0.05）, and AU of zincum, cuprum and ferrum was all improved in the rhGH group （P 〈 0.05）. The mean blood glucose level was significantly higher in the rhGH group than in the placebo group from d 3 to d 6 after operation （P 〈 0.05）.improves the retention of zincum, cuprum and ferrum and decreases the excretion of zincum, cuprum and ferrum, improves the balance of zincum, cuprum and ferrum, and promotes the AA and AU of zincum, cuprum and ferrum, rhGH can be well tolerated without significant adverse effects and the blood glucose level can be well controlled.展开更多
基金supported by the National Natural Science Foundation of China(No.52174266)the State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization,Kunming,China(No.CNMRCUKF2109)the Education Foundation of Central South University,China(No.GCY2021376Y)。
文摘The dissolution mechanism of marmatite in the presence of Cu^(2+)was intensively studied by experiments and density functional theory(DFT) calculations. Leaching experiments showed that Cu^(2+)accelerated marmatite dissolution at high temperatures(above 55 ℃), but the trend was reversed at low temperatures(below 45 ℃), which may be because the reaction mechanism between Cu^(2+)and marmatite changed from surface adsorption to bulk substitution with increasing temperature. The substitution reaction caused more zinc atoms in the marmatite crystal lattice to be released and enhanced the electrochemical reactivity, while the adsorption of copper ions at low temperatures would passivate marmatite, thus inhibiting the reaction process. DFT calculations showed that the energy of the substitution reaction was more negative than that of the adsorption reaction at high temperatures, which further verified the proposed mechanism.
基金Supported by Scientific Operating Expenses of Hainan Province(11-201410-0009)~~
文摘This study aimed to investigate the effects of copper and manganese on hemocyte apoptosis and the antagonism of iron and zinc in Oreochromis niloticus The heavy metal contents in fish blood and feed were determined by atomic absorption spectrophotometry, and the hemocyte apoptosis was determined by flow cytometry. A total of 360 tilapias were selected, and they were divided randomly and evenly into 12 groups. In the challenge groups, the tilapias were fed with con stant-level copper sulfate（0, 200 mg/kg） and manganese sulfate（0, 120 mg/kg）; in the antagonism groups, the tilapias were fed with constant-level zinc sulfate（20320 mg/kg） and iron sulfate（150, 350 mg/kg）. After 20-week aquaculture, the hemocyte apoptosis rates in the copper and manganese groups were significantly increased; with the increased addition levels of iron and zinc, the hemocyte apopto sis rates in the iron and zinc groups were significantly reduced, but they were stil higher than that in the control group. In conclusion, excessive copper and manganese can cause apoptosis in hemocytes of O. niloticus. However, the toxic effects of copper and manganese can be antagonized by iron and zinc.
文摘The distribution of various fractions of Zn, Fe, Cu and Mn in 15 types of sods in China and its rela-tionship with plant availability were studied. Wactions of various elements were found to have some similarcharacteristic distribution regularities in wirious types of soils, but various soil types derered to varyingdegrees in the distribution of each fraction. Soil physico-chemical properties, such as pH, CEC and thecontents of OM, CaCO_3, free Fe, free Mn and P_2O_5, were signdicantly correlated with the distribution ofelemental fractions, and a significazit correlation also existed between the distribution and plant amilabilityof elemental fractions. Varfous fractions of each element were divided into two groups bed on their plantavailability. The correlation between the distribution of combination fractions aiid plaxit availability indi-cated a significantly or an extremely significantly positive correlation for Group I but a significantly or anextremely significantly negative correlation for Group II. Therefore, the fractions in Group I were primarypools of available nutrients, while those in Group II could hardly provide available nutrients for plants. Descreasing the transformation of corresponding elements into fractions of Group 11 and increasing the storagecapacity of various fractions of Group I were an important direction for regulation and controiling of soilnutrients. However, some Particular soils with too high contents of Zn, Fe, Cu and Mn should be regulatedand controlled adversely
文摘Samples of 21 soil profiles and 165 top soils from an area of approximate 1.5km^2 on red-earthy hill landscape were collected and analysed.The content of Ca,Mg,K,P,Fe,Mn,Zn and Cu in soils relate with the kind of parent material and the position of topography,however,there is great variation due to the local difference of the form of soil utilization.From the difference in spatial distribution of elements content,it is believed that eight kinds of elements are lost by chemical leaching and physical translocation,meanwhile some are added (such as Ca,P,K,Mg) and some mobilized (such as Fe,Mn,Zn,Cu and P) through cultivation,fertilization and irrigation in the soils on the landscape investigated.The sectional differentiation in abundance or deficiency of elements in top soils on the landscape investigated is distinct,which is important for carrying out agricultural management and reasonable fertilization according to local conditions.
基金This work is supported by the National Natural Science Focal Projects Foundation of China(Grant No.40131020)the National Natural Science Foundation of China(Grant No.49833030)+2 种基金the Venus Program Foundation for Young Scientists of Shanghai(Grant No.97QA14023)its Tracking Program(Grant No.01QMH1406)the Dawn Program of Shanghai Ecucational Development Foundation.
文摘The five chemical associations of heavy metals have been extracted continuously using the Tessier extracting method. Results show that Cu, Pb, Fe, Zn and Cr in the sediments are mainly distributed in residual fraction, while the major chemical association of Mn is carbonates. Carbonate heavy metals are converted into Fe-Mn oxides in autumn. And in the low tidal flat, after carbonates have changed into ionic heavy metals, some of the elements are transported to the overlying water. Cu, Pb, Fe and Mn have good correlations with each other, and Zn, Cr also show their similarity of chemical behavior in the sediments.
文摘AIM： To investigate the effects of short-term application of low-dose growth hormone on trace element metabolism and blood glucose in surgical patients METHODS： A total of 48 consecutive patients undergoing abdominal operations were randomized to receive either subcutaneous rhGH （0.15 IU/kg） or placebo （menstruum） injections daily for 7 d after surgery. The two groups had similar nutrition intake. Blood, feces, urine and drain samples were collected to measure zincum, cuprum and ferrum as well as glucose levels. Accumulative intake, excretion and balance of zincum, cuprum and ferrum, apparent absorption （AA） and apparent utilization （AU） of zincum, cuprum and ferrum, blood glucose levels and adverse events were estimated. RESULTS： There were no differences in accumulative intake and drain excretion between the two groups. The feces excretion and accumulative excretion of cuprum were lower in the rhGH group （P 〈 0.05）. The urinary excretion of zincum, cuprum and ferrum was all significantly decreased in the rhGH group （P 〈 0.05） and the accumulative balance of zincum, cuprum and ferrum was improved compared with the placebo group （P 〈 0.05）. AA of cuprum in the rhGH group was almost twice as much as the placebo group （P 〈 0.05）, and AU of zincum, cuprum and ferrum was all improved in the rhGH group （P 〈 0.05）. The mean blood glucose level was significantly higher in the rhGH group than in the placebo group from d 3 to d 6 after operation （P 〈 0.05）.improves the retention of zincum, cuprum and ferrum and decreases the excretion of zincum, cuprum and ferrum, improves the balance of zincum, cuprum and ferrum, and promotes the AA and AU of zincum, cuprum and ferrum, rhGH can be well tolerated without significant adverse effects and the blood glucose level can be well controlled.
