Delays in sowing have significant effects on the grain yield,yield components,and grain protein concentrations of winter wheat.However,little is known about how delayed sowing affects these characteristics at differen...Delays in sowing have significant effects on the grain yield,yield components,and grain protein concentrations of winter wheat.However,little is known about how delayed sowing affects these characteristics at different positions in the wheat spikes.In this study,the effects of sowing date were investigated in a winter wheat cultivar,Shannong 30,which was sown in 2019 and 2020 on October 8(normal sowing)and October 22(late sowing)under field conditions.Delayed sowing increased the partitioning of ^(13)C-assimilates to spikes,particularly to florets at the apical section of a spike and those occupying distal positions on the same spikelet.Consequently,the increase in grain number was the greatest for the apical sections,followed by the basal and central sections.No significant differences were observed between sowing dates in the superior grain number in the basal and central sections,while the number in apical sections was significantly different.The number of inferior grains in each section also increased substantially in response to delayed sowing.The average grain weights in all sections remained unchanged under delayed sowing because there were parallel increases in grain number and ^(13)C-assimilate partitioning to grains at specific positions in the spikes.Increases in grain number m^(–2) resulted in reduced grain protein concentrations as the limited nitrogen supply was diluted into more grains.Delayed sowing caused the greatest reduction in grain protein concentration in the basal sections,followed by the central and apical sections.No significant differences in the reduction of the grain protein concentration were observed between the inferior and superior grains under delayed sowing.In conclusion,a 2-week delay in sowing improved grain yield through increased grain number per spike,which originated principally from an increased grain number in the apical sections of spikes and in distal positions on the same spikelet.However,grain protein concentrations declined in each section because of the increased grain number and reduced N uptake.展开更多
Since it is unrealistic to do an experimental mixture assessment on every possible combination, mathematical model plays an important role in predicting the mixture toxicity. The present study is devoted to the furthe...Since it is unrealistic to do an experimental mixture assessment on every possible combination, mathematical model plays an important role in predicting the mixture toxicity. The present study is devoted to the further application of linear concentration addition(CA)-based model(LCA) and independent action(IA)-based model(LIA) to predict the non-interactive mixture toxicity. The 26 mixtures including 312 data points were used to evaluate the predictive powers of LCA and LIA models. The models were internally validated using the leave-one-out cross-validation and y-randomization test, and the external validations were evaluated by the test tests. Both LCA and LIA models agree well with the experimental values for all mixture toxicity, and present high internally(R2 and Q2 〉 0.98) and externally(Q2F1, Q2F2, and Q2F3 〉 0.99) predictive power. The use of LCA and LIA led to improved predictions compared to the estimates based on the CA and IA models. Both LCA and LIA were found to be appropriate methods for modeling toxicity of non-interactive chemical mixtures.展开更多
Dietary supplements represent an increasingly common source of drug-induced liver injury. Hydroxycut is a popular weight loss supplement which has previously been linked to hepatotoxicity, although the individual chem...Dietary supplements represent an increasingly common source of drug-induced liver injury. Hydroxycut is a popular weight loss supplement which has previously been linked to hepatotoxicity, although the individual chemical components underlying liver injury remain poorly understood. We report two cases of acute hepatitis in the setting of Hydroxycut exposure and describe possible mechanisms of liver injury. We also comprehensively review and summarize the existing literature on commonly used weight loss supplements, and their individual components which have demon-strated potential for liver toxicity. An increased effort to screen for and educate patients and physicians about supplement-associated hepatotoxicity is warranted.展开更多
The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid ...The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid crystalline solution for chitin, chitosan, cyanoethyl chitosan and propionyl chitin successively increases as the chain rigidity decreases. Therefore it can be used as an indicator of the chain rigidity.展开更多
Objective: This study is designed to observe the chronic toxicity after the administration of mulberry sea-buckthorn beverage concentrate for 3 months on rats and to predict the possible adverse effect and the potenti...Objective: This study is designed to observe the chronic toxicity after the administration of mulberry sea-buckthorn beverage concentrate for 3 months on rats and to predict the possible adverse effect and the potential toxicity target organs. Method: The rats (SPF level) were randomly divided into high-dose (20 mL/kg BW), middle-dose (10 mL/kg BW), low-dose (5 mL/kg BW) groups and negative control group (20 mL/kg BW of purified water) with 30 rats in each group. Each group was orally given mulberry sea-buckthorn beverage concentrate for 3 months and recovered by stop feeding samples for 2 weeks for a recovery observation. The rats’ general condition, the organ coefficient, the indexes of hematology and blood biochemistry and the histological changes of the main organs were determined. Result: The appearance and behavior of activity in rats showed no anomalies in all these groups and all the rats put on weight during this period. Comparing to the negative control group, no obvious differences were observed in the weekly weight and organ coefficient of each dose group. After 3 months of administration, HGB in both mulberry sea-buckthorn beverage concentrate low-dose group and high-dose group were increased. No significant differences were observed in the indexes of hematology after 2 weeks of recovery. CREA in low-dose, middle-dose and high-dose groups were significantly increased after 3 months of administration and it remained in the high level in middle-dose and high-dose group even after 2 weeks of recovery. No drug-related lesions were observed in the histological changes of major organs. Conclusion: The results show that long term use of mulberry concentrated sea-buckthorn beverage can lead to increased CREA, which suggested kidney toxicity. Although no obvious pathological change was found in kidney, we should pay attention to chronic kidney damage in the further research.展开更多
It becomes a key technology to measure the concentration of the vehicle exhaust components with the absorption spectra. But because of the overlap of gas absorption bands, how to separate the absorption information of...It becomes a key technology to measure the concentration of the vehicle exhaust components with the absorption spectra. But because of the overlap of gas absorption bands, how to separate the absorption information of each component gas from the mixed absorption spectra has become the key point to restrict the precision of the optical detection method. In this paper, the ex-perimental platform for the absorption spectrum of vehicle exhaust components has been established. Based on the ultraviolet absorption spectra measured with the platform of exhaust gas NO & NO2, the concentration regression model for the two components has been established with weighted partial least squares regression (WPLS). Finally the each spectral characteristic information of NO & NO2 gas has been separated and the concentration of each corresponding component has been reversed successfully.展开更多
The molecular electronegativity interaction vector (MEIV) was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression (MLR) and p...The molecular electronegativity interaction vector (MEIV) was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression (MLR) and partial least-squares regression (PLS). The correlation coefficients (R) of the two models were 0.945 and 0.941, respectively. The models were evaluated by performing the cross validation with the leave-one-out (LOO) procedure. The cross-verification correlation coefficients (RCV) of the two models were 0.921 and 0.919, respectively. The results showed that the models constructed in this work could provide estimation stability and favorable predictive ability.展开更多
Objective To determine the effects of water hardness on the toxicities of cobalt (Co) and nickel (Ni) to a freshwater fish, Capoetafusca. Methods Toxicity was investigated by static bioassay. Fish were exposed to ...Objective To determine the effects of water hardness on the toxicities of cobalt (Co) and nickel (Ni) to a freshwater fish, Capoetafusca. Methods Toxicity was investigated by static bioassay. Fish were exposed to cobalt (as COCI2) and nickel (as NiCI2) for 96 h in waters with two levels of hardness ("hard" and "very hard", nominally 130 mg/L and 350 mg/L as CaCO3, respectively). Results Water hardness had a significant effect on the acute toxicity of both elements. The 96 h LC50 values for Co were 91.7 mg/L and 204.8 mg/L in hard and very hard waters, respectively, and for Ni the 96 h LC50 values were 78.0 mg/L and 127.2 mg/L, respectively. Conclusion The fish were more sensitive to Co and Ni toxicity in hard water than in very hard water; very hard water protects C. fusca against the toxicity of Co and Ni.展开更多
The acute toxicity of 4 drugs, dipterex, potassium permanganate, copper sulfate and formaldehyde to larvae of black-spot hybrid snakehead was tested with the semi hydrostatic test method under water temperature of (2...The acute toxicity of 4 drugs, dipterex, potassium permanganate, copper sulfate and formaldehyde to larvae of black-spot hybrid snakehead was tested with the semi hydrostatic test method under water temperature of (28.3± 1.5)℃, pH of(8.01 ±0.12) and dissolved oxygen of (4.6 ±0.5) mg/L. The results showed that 96 h median-lethal concentration (LCso) of copper sulphate was the lowest, 1. 586 mg/L, while 96 h LC50 of formaldehyde was the highest, 115. 159 mg/L. The toxicity of the 4 drugs ranked in the order of copper sulphate, dipterex, potassium permanganate and formaldehyde from high to low. The safe concentrations(SCs) of the 4 drugs were in order of formaldehyde (35. 529 mg/L), potassium permanganate ( 1. 277 mg/L), dipterex ( 1. 450 mg/L) and copper sulphate (0.882 mg/L). According to the rosults,the SCs of dipterex, formaldehyde and copper sulphate were higher than the conventional dosage, they were safe to be used for control of corresponding diseases of Channa argus by the conventional dosage. The SC of potassium permanganate was in the conventional dosage range, so it could be used for control of diseases in accordance with the SC of C. argus to the drug in production.展开更多
We studied acute and joint toxicity of three different agrochemicals(chlorantraniliprole, flubendiamide-abamectin and penoxsulam) to Chinese tiger frog(Hoplobatrachus chinensis) tadpoles with the method of stability w...We studied acute and joint toxicity of three different agrochemicals(chlorantraniliprole, flubendiamide-abamectin and penoxsulam) to Chinese tiger frog(Hoplobatrachus chinensis) tadpoles with the method of stability water tests. Results showed that the three agrochemicals increased tadpole mortality. For acute toxicity, the LC50 values after 24, 48 and 72 h of chlorantraniliprole, flubendiamide-abamectin and penoxsulam exposure were 5.37, 4.90 and 4.68 mg/L; 0.035, 0.025 and 0.021 mg/L; 1.74, 1.45 and 1.29 mg/L, respectively. The safety concentrations(SC) of chlorantraniliprole, flubendiamide-abamectin and penoxsulam to the tadpoles were 1.23, 0.30 and 0.003 mg/L, respectively. Based on these findings, chlorantraniliprole and penoxsulam were moderately toxic, while flubendiamide-abamectin was highly toxic. All pairwise joint toxicity tests showed moderate toxicity. The LC50 values after 24, 48 and 72 h of exposure were 7.08, 6.61 and 6.03 mg/L for chlorantraniliprole+penoxsulam, with corresponding values of 2.455, 2.328 and 2.183 mg/L for chlorantraniliprole+flubendiamide-abamectin, and 1.132, 1.084 and 1.050 mg/L for penoxsulam+flubendiamide-abamectin, with safe concentrations of 1.73, 0.63 and 0.30 mg/L, respectively. For toxic evaluations of pairwise combinations of the three agrochemicals, only the joint toxicity of chlorantraniliprole and flubendiamide-abamectin after 24 h was found to be synergistic, whereas all other tests were antagonistic. Our findings provide valuable information on the toxic effects of agrochemicals on amphibians and how various types of agrochemicals can be reasonably used in agricultural areas.展开更多
Cerrado soils are acidic and nutrient-poor,with high content of solubilized Al 3+.Plants growing in these conditions may display adaptations to cope with high aluminum concentrations especially during early developmen...Cerrado soils are acidic and nutrient-poor,with high content of solubilized Al 3+.Plants growing in these conditions may display adaptations to cope with high aluminum concentrations especially during early developmental stages.We investigated leaf nutritional status,and photosynthetic and growth characteristics during the initial establishment of Handroanthus impetiginosus(Mart.Ex Dc.)Mattos,a secondary tree species distributed in the Brazilian Cerrado.Our goal was to understand leaf-level traits related to diff erent aluminum concentrations.H.impetiginosus plants were cultivated in four diff erent aluminum sulfate concentrations:0,1,2,and 4 mM Al,for 40 days.We performed analyses of growth,leaf gas exchange,chloroplast pigment content,and leaf mineral nutrients.We observed a linear increase of Al leaf content as a function of Al concentration in the nutrient solution.Plants grown in 1 mM Al showed a remarkable increase of K leaf content,net photosynthesis,stomatal conductance,and transpiration,while in 4 mM Al there were reductions of N,P,and K contents,gas exchange characteristics,and height.H.impetiginosus did not have mechanisms of avoidance,compartmentalization,or resistance to high Al concentrations.Indeed,this species showed a hormetic response,with low Al concentrations stimulating and high Al concentrations inhibiting plant responses.展开更多
Micronutrient status of top soils (0 - 25 cm) collected from intensively cultivated soils (typic dystrandept) in the Bambouto highland of Cameroon was investigated. Thirty-six soil samples were collected within a 100 ...Micronutrient status of top soils (0 - 25 cm) collected from intensively cultivated soils (typic dystrandept) in the Bambouto highland of Cameroon was investigated. Thirty-six soil samples were collected within a 100 m × 100 m grid. 16 of them were analyzed for pH, organic carbon, cation exchange capacity (CEC), Total N (totN), available P, exchangeable K, Ca and Mg, and 36 samples were analyzed for Cu, Mn, Fe and Zn. The status of trace elements was compared with soil critical levels and soil-based risk thresholds, and was declared deficient, sufficient or toxic. The soils were generally, slightly acidic, of high organic and nitrogen status and of adequate concentrations in exchangeable bases and available P. Mean values of Fe, Cu, Mn and Zn were 58.59, 0.52, 29.20 and 4.99 ppm, respectively. Relative to critical levels, 53% and 8% of the soils examined were deficient in Cu and Zn respectively while in all soils, Fe and Mn were above critical levels. The concentrations of the micronutrients investigated (except for Fe in 3% of the soils) were lower than toxic thresholds prescribed by European Economic Community (EEC) and the United States Environmental Protection Agency. Farmers’ current level of agricultural intensification has no threats on micronutrient toxicity. However, because of Cu and Zn deficiency observed in some fields, an analysis of spatial variability is required to guide site specific soil nutrient management. Furthermore, in order to obtain quality produce and protect the environment, a balanced fertilizer recommendation including NPK + Cu + Zn is required for intensively cultivated typic dystrandept soils in the Bambouto highlands.展开更多
Antiretroviral therapy in HIV patients is known for its negative effect on the cardiovascular system. One of the major adverse events in patients on lopinavir is increasing lipids. Hyperlipidaemia together with chroni...Antiretroviral therapy in HIV patients is known for its negative effect on the cardiovascular system. One of the major adverse events in patients on lopinavir is increasing lipids. Hyperlipidaemia together with chronic inflammation by HIV-infection itself makes these patients prone for cardiovascular diseases.The purpose of this study (a sub study within the FREE-study) was to determine if higher plasma lopinavir (LPV) concentrations lead to increase of serum lipids. Plasma drug concentrations were analysed up to week 24 in a prospective cohort of HIV antiretroviral therapy naive patients who started on a regimen of zidovudine, lamivudine and ritonavir-boosted lopinavir (FREE study). Prospectively we measured plasma lopinavir concentrations from baseline to week 24 in 72 naive HIV-patients starting on lopinavir (59 males and 13 females). A total of 210 samples were analysed, with at least 2 samples in every patient. Mean LPV trough concentration was 4.3 mg/L (± 2.1). The median intra-subject variation in LPV level was 38% (range 4% - 111%). Serum lipids were not correlated to LPV plasma concentrations possibly due to the wide intra-individual variability in LPV trough levels. Monitoring of plasma lopinavir and subsequent dose adjustment of LPV will not be useful to prevent hyperlipidaemia in HIV-patients treated with lopinavir.展开更多
Globally, the generation of produced water keeps increasing due to depleting wells and about 40% of this wastewater is disposed of into the environment. Produced water is made up of several components that are toxic i...Globally, the generation of produced water keeps increasing due to depleting wells and about 40% of this wastewater is disposed of into the environment. Produced water is made up of several components that are toxic in nature, like production chemicals that are used for oil and gas production activities. Oxygen scavenger and defoamer are commonly used for corrosion prevention as both are applied at different stages of corrosion prevention. Evaluation of the possible synergistic toxicity contribution of oxygen scavenger and defoamer formed the basis of this research and was conducted using the <i>Tilapia guineensis</i> as bio-indicator. The toxicity test was carried out using the ELIMINOX (oxygen scavenger) and EC9017A (defoamer) individually and both chemicals were combined together. The choice of these chemicals was premised on previous researches that have confirmed that they are toxic individually, without further research on how they interact when they are combined. These chemicals and freshwater were used to generate produced water samples in the laboratory. The experiment was set up by adding ten fishes into each of the glass containers, containing the produced water samples at different concentrations and a control sample without the chemicals. The rate of mortality of the fish for the individual chemicals ranged from 100% to 10% for the different percentage concentrations. While on the other hand, a combination of the two chemicals had more survival than mortality, the percentage survival rate ranged from 100% to 90% across all the percentage concentrations. The lethal concentration also showed that the oxygen scavenger was more toxic than the defoamer, however, when they were combined;they showed an antagonistic relationship as the toxicity of the oxygen scavenger drastically reduced. The research findings intend to create awareness of the possible interaction of production chemicals when they are used for oil and gas activities and their combined toxicity contribution to produced water. This will in turn aid government regulators in their decision-making for disposal of produced water.展开更多
基金Financial support was received from the National Key Research and Development Program of China(2016YFD0300403 and 2017YFD0201705)。
文摘Delays in sowing have significant effects on the grain yield,yield components,and grain protein concentrations of winter wheat.However,little is known about how delayed sowing affects these characteristics at different positions in the wheat spikes.In this study,the effects of sowing date were investigated in a winter wheat cultivar,Shannong 30,which was sown in 2019 and 2020 on October 8(normal sowing)and October 22(late sowing)under field conditions.Delayed sowing increased the partitioning of ^(13)C-assimilates to spikes,particularly to florets at the apical section of a spike and those occupying distal positions on the same spikelet.Consequently,the increase in grain number was the greatest for the apical sections,followed by the basal and central sections.No significant differences were observed between sowing dates in the superior grain number in the basal and central sections,while the number in apical sections was significantly different.The number of inferior grains in each section also increased substantially in response to delayed sowing.The average grain weights in all sections remained unchanged under delayed sowing because there were parallel increases in grain number and ^(13)C-assimilate partitioning to grains at specific positions in the spikes.Increases in grain number m^(–2) resulted in reduced grain protein concentrations as the limited nitrogen supply was diluted into more grains.Delayed sowing caused the greatest reduction in grain protein concentration in the basal sections,followed by the central and apical sections.No significant differences in the reduction of the grain protein concentration were observed between the inferior and superior grains under delayed sowing.In conclusion,a 2-week delay in sowing improved grain yield through increased grain number per spike,which originated principally from an increased grain number in the apical sections of spikes and in distal positions on the same spikelet.However,grain protein concentrations declined in each section because of the increased grain number and reduced N uptake.
基金supported by the National Natural Science Foundation of China(21407032,21667013,51578171)Natural Science Foundation of Guangxi Province(2014GXNSFBA118233)Guilin Scientific Research and Technology Development Program(2016012505)
文摘Since it is unrealistic to do an experimental mixture assessment on every possible combination, mathematical model plays an important role in predicting the mixture toxicity. The present study is devoted to the further application of linear concentration addition(CA)-based model(LCA) and independent action(IA)-based model(LIA) to predict the non-interactive mixture toxicity. The 26 mixtures including 312 data points were used to evaluate the predictive powers of LCA and LIA models. The models were internally validated using the leave-one-out cross-validation and y-randomization test, and the external validations were evaluated by the test tests. Both LCA and LIA models agree well with the experimental values for all mixture toxicity, and present high internally(R2 and Q2 〉 0.98) and externally(Q2F1, Q2F2, and Q2F3 〉 0.99) predictive power. The use of LCA and LIA led to improved predictions compared to the estimates based on the CA and IA models. Both LCA and LIA were found to be appropriate methods for modeling toxicity of non-interactive chemical mixtures.
文摘Dietary supplements represent an increasingly common source of drug-induced liver injury. Hydroxycut is a popular weight loss supplement which has previously been linked to hepatotoxicity, although the individual chemical components underlying liver injury remain poorly understood. We report two cases of acute hepatitis in the setting of Hydroxycut exposure and describe possible mechanisms of liver injury. We also comprehensively review and summarize the existing literature on commonly used weight loss supplements, and their individual components which have demon-strated potential for liver toxicity. An increased effort to screen for and educate patients and physicians about supplement-associated hepatotoxicity is warranted.
基金Supported by the Laboratory of Cellulose and Lignocellulosics Chemistry. Chinese Academy of Sciences and National Natural Science Foundation. China
文摘The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid crystalline solution for chitin, chitosan, cyanoethyl chitosan and propionyl chitin successively increases as the chain rigidity decreases. Therefore it can be used as an indicator of the chain rigidity.
文摘Objective: This study is designed to observe the chronic toxicity after the administration of mulberry sea-buckthorn beverage concentrate for 3 months on rats and to predict the possible adverse effect and the potential toxicity target organs. Method: The rats (SPF level) were randomly divided into high-dose (20 mL/kg BW), middle-dose (10 mL/kg BW), low-dose (5 mL/kg BW) groups and negative control group (20 mL/kg BW of purified water) with 30 rats in each group. Each group was orally given mulberry sea-buckthorn beverage concentrate for 3 months and recovered by stop feeding samples for 2 weeks for a recovery observation. The rats’ general condition, the organ coefficient, the indexes of hematology and blood biochemistry and the histological changes of the main organs were determined. Result: The appearance and behavior of activity in rats showed no anomalies in all these groups and all the rats put on weight during this period. Comparing to the negative control group, no obvious differences were observed in the weekly weight and organ coefficient of each dose group. After 3 months of administration, HGB in both mulberry sea-buckthorn beverage concentrate low-dose group and high-dose group were increased. No significant differences were observed in the indexes of hematology after 2 weeks of recovery. CREA in low-dose, middle-dose and high-dose groups were significantly increased after 3 months of administration and it remained in the high level in middle-dose and high-dose group even after 2 weeks of recovery. No drug-related lesions were observed in the histological changes of major organs. Conclusion: The results show that long term use of mulberry concentrated sea-buckthorn beverage can lead to increased CREA, which suggested kidney toxicity. Although no obvious pathological change was found in kidney, we should pay attention to chronic kidney damage in the further research.
文摘It becomes a key technology to measure the concentration of the vehicle exhaust components with the absorption spectra. But because of the overlap of gas absorption bands, how to separate the absorption information of each component gas from the mixed absorption spectra has become the key point to restrict the precision of the optical detection method. In this paper, the ex-perimental platform for the absorption spectrum of vehicle exhaust components has been established. Based on the ultraviolet absorption spectra measured with the platform of exhaust gas NO & NO2, the concentration regression model for the two components has been established with weighted partial least squares regression (WPLS). Finally the each spectral characteristic information of NO & NO2 gas has been separated and the concentration of each corresponding component has been reversed successfully.
基金supported by the Youth Foundation of Education Bureau, Sichuan Province (09ZB036)Technology Bureau, Sichuan Province (2006j13-141)
文摘The molecular electronegativity interaction vector (MEIV) was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression (MLR) and partial least-squares regression (PLS). The correlation coefficients (R) of the two models were 0.945 and 0.941, respectively. The models were evaluated by performing the cross validation with the leave-one-out (LOO) procedure. The cross-verification correlation coefficients (RCV) of the two models were 0.921 and 0.919, respectively. The results showed that the models constructed in this work could provide estimation stability and favorable predictive ability.
文摘Objective To determine the effects of water hardness on the toxicities of cobalt (Co) and nickel (Ni) to a freshwater fish, Capoetafusca. Methods Toxicity was investigated by static bioassay. Fish were exposed to cobalt (as COCI2) and nickel (as NiCI2) for 96 h in waters with two levels of hardness ("hard" and "very hard", nominally 130 mg/L and 350 mg/L as CaCO3, respectively). Results Water hardness had a significant effect on the acute toxicity of both elements. The 96 h LC50 values for Co were 91.7 mg/L and 204.8 mg/L in hard and very hard waters, respectively, and for Ni the 96 h LC50 values were 78.0 mg/L and 127.2 mg/L, respectively. Conclusion The fish were more sensitive to Co and Ni toxicity in hard water than in very hard water; very hard water protects C. fusca against the toxicity of Co and Ni.
基金Supported by Agricultural Improved Variety Project of Shandong Province
文摘The acute toxicity of 4 drugs, dipterex, potassium permanganate, copper sulfate and formaldehyde to larvae of black-spot hybrid snakehead was tested with the semi hydrostatic test method under water temperature of (28.3± 1.5)℃, pH of(8.01 ±0.12) and dissolved oxygen of (4.6 ±0.5) mg/L. The results showed that 96 h median-lethal concentration (LCso) of copper sulphate was the lowest, 1. 586 mg/L, while 96 h LC50 of formaldehyde was the highest, 115. 159 mg/L. The toxicity of the 4 drugs ranked in the order of copper sulphate, dipterex, potassium permanganate and formaldehyde from high to low. The safe concentrations(SCs) of the 4 drugs were in order of formaldehyde (35. 529 mg/L), potassium permanganate ( 1. 277 mg/L), dipterex ( 1. 450 mg/L) and copper sulphate (0.882 mg/L). According to the rosults,the SCs of dipterex, formaldehyde and copper sulphate were higher than the conventional dosage, they were safe to be used for control of corresponding diseases of Channa argus by the conventional dosage. The SC of potassium permanganate was in the conventional dosage range, so it could be used for control of diseases in accordance with the SC of C. argus to the drug in production.
基金This work was supported by the National Natural Science Foundation of China (31270443) and the Natural Science Foundation of Zhejiang Province (LY13C030004). Acknowledgements: We would like to thank Fang LIU and Dan WU for their assistance with the experiments.
文摘We studied acute and joint toxicity of three different agrochemicals(chlorantraniliprole, flubendiamide-abamectin and penoxsulam) to Chinese tiger frog(Hoplobatrachus chinensis) tadpoles with the method of stability water tests. Results showed that the three agrochemicals increased tadpole mortality. For acute toxicity, the LC50 values after 24, 48 and 72 h of chlorantraniliprole, flubendiamide-abamectin and penoxsulam exposure were 5.37, 4.90 and 4.68 mg/L; 0.035, 0.025 and 0.021 mg/L; 1.74, 1.45 and 1.29 mg/L, respectively. The safety concentrations(SC) of chlorantraniliprole, flubendiamide-abamectin and penoxsulam to the tadpoles were 1.23, 0.30 and 0.003 mg/L, respectively. Based on these findings, chlorantraniliprole and penoxsulam were moderately toxic, while flubendiamide-abamectin was highly toxic. All pairwise joint toxicity tests showed moderate toxicity. The LC50 values after 24, 48 and 72 h of exposure were 7.08, 6.61 and 6.03 mg/L for chlorantraniliprole+penoxsulam, with corresponding values of 2.455, 2.328 and 2.183 mg/L for chlorantraniliprole+flubendiamide-abamectin, and 1.132, 1.084 and 1.050 mg/L for penoxsulam+flubendiamide-abamectin, with safe concentrations of 1.73, 0.63 and 0.30 mg/L, respectively. For toxic evaluations of pairwise combinations of the three agrochemicals, only the joint toxicity of chlorantraniliprole and flubendiamide-abamectin after 24 h was found to be synergistic, whereas all other tests were antagonistic. Our findings provide valuable information on the toxic effects of agrochemicals on amphibians and how various types of agrochemicals can be reasonably used in agricultural areas.
基金This study was financed in part by the Coordenacao de Aperfeicamento de Pessoal de Nível Superior-Brazil(CAPES)-Financial Code 001 and the Conselho Nacional de Desenvolvimento Científicoe Tecnológico-Brazil(CNPq)by providing scholarship for the authors.
文摘Cerrado soils are acidic and nutrient-poor,with high content of solubilized Al 3+.Plants growing in these conditions may display adaptations to cope with high aluminum concentrations especially during early developmental stages.We investigated leaf nutritional status,and photosynthetic and growth characteristics during the initial establishment of Handroanthus impetiginosus(Mart.Ex Dc.)Mattos,a secondary tree species distributed in the Brazilian Cerrado.Our goal was to understand leaf-level traits related to diff erent aluminum concentrations.H.impetiginosus plants were cultivated in four diff erent aluminum sulfate concentrations:0,1,2,and 4 mM Al,for 40 days.We performed analyses of growth,leaf gas exchange,chloroplast pigment content,and leaf mineral nutrients.We observed a linear increase of Al leaf content as a function of Al concentration in the nutrient solution.Plants grown in 1 mM Al showed a remarkable increase of K leaf content,net photosynthesis,stomatal conductance,and transpiration,while in 4 mM Al there were reductions of N,P,and K contents,gas exchange characteristics,and height.H.impetiginosus did not have mechanisms of avoidance,compartmentalization,or resistance to high Al concentrations.Indeed,this species showed a hormetic response,with low Al concentrations stimulating and high Al concentrations inhibiting plant responses.
文摘Micronutrient status of top soils (0 - 25 cm) collected from intensively cultivated soils (typic dystrandept) in the Bambouto highland of Cameroon was investigated. Thirty-six soil samples were collected within a 100 m × 100 m grid. 16 of them were analyzed for pH, organic carbon, cation exchange capacity (CEC), Total N (totN), available P, exchangeable K, Ca and Mg, and 36 samples were analyzed for Cu, Mn, Fe and Zn. The status of trace elements was compared with soil critical levels and soil-based risk thresholds, and was declared deficient, sufficient or toxic. The soils were generally, slightly acidic, of high organic and nitrogen status and of adequate concentrations in exchangeable bases and available P. Mean values of Fe, Cu, Mn and Zn were 58.59, 0.52, 29.20 and 4.99 ppm, respectively. Relative to critical levels, 53% and 8% of the soils examined were deficient in Cu and Zn respectively while in all soils, Fe and Mn were above critical levels. The concentrations of the micronutrients investigated (except for Fe in 3% of the soils) were lower than toxic thresholds prescribed by European Economic Community (EEC) and the United States Environmental Protection Agency. Farmers’ current level of agricultural intensification has no threats on micronutrient toxicity. However, because of Cu and Zn deficiency observed in some fields, an analysis of spatial variability is required to guide site specific soil nutrient management. Furthermore, in order to obtain quality produce and protect the environment, a balanced fertilizer recommendation including NPK + Cu + Zn is required for intensively cultivated typic dystrandept soils in the Bambouto highlands.
文摘Antiretroviral therapy in HIV patients is known for its negative effect on the cardiovascular system. One of the major adverse events in patients on lopinavir is increasing lipids. Hyperlipidaemia together with chronic inflammation by HIV-infection itself makes these patients prone for cardiovascular diseases.The purpose of this study (a sub study within the FREE-study) was to determine if higher plasma lopinavir (LPV) concentrations lead to increase of serum lipids. Plasma drug concentrations were analysed up to week 24 in a prospective cohort of HIV antiretroviral therapy naive patients who started on a regimen of zidovudine, lamivudine and ritonavir-boosted lopinavir (FREE study). Prospectively we measured plasma lopinavir concentrations from baseline to week 24 in 72 naive HIV-patients starting on lopinavir (59 males and 13 females). A total of 210 samples were analysed, with at least 2 samples in every patient. Mean LPV trough concentration was 4.3 mg/L (± 2.1). The median intra-subject variation in LPV level was 38% (range 4% - 111%). Serum lipids were not correlated to LPV plasma concentrations possibly due to the wide intra-individual variability in LPV trough levels. Monitoring of plasma lopinavir and subsequent dose adjustment of LPV will not be useful to prevent hyperlipidaemia in HIV-patients treated with lopinavir.
文摘Globally, the generation of produced water keeps increasing due to depleting wells and about 40% of this wastewater is disposed of into the environment. Produced water is made up of several components that are toxic in nature, like production chemicals that are used for oil and gas production activities. Oxygen scavenger and defoamer are commonly used for corrosion prevention as both are applied at different stages of corrosion prevention. Evaluation of the possible synergistic toxicity contribution of oxygen scavenger and defoamer formed the basis of this research and was conducted using the <i>Tilapia guineensis</i> as bio-indicator. The toxicity test was carried out using the ELIMINOX (oxygen scavenger) and EC9017A (defoamer) individually and both chemicals were combined together. The choice of these chemicals was premised on previous researches that have confirmed that they are toxic individually, without further research on how they interact when they are combined. These chemicals and freshwater were used to generate produced water samples in the laboratory. The experiment was set up by adding ten fishes into each of the glass containers, containing the produced water samples at different concentrations and a control sample without the chemicals. The rate of mortality of the fish for the individual chemicals ranged from 100% to 10% for the different percentage concentrations. While on the other hand, a combination of the two chemicals had more survival than mortality, the percentage survival rate ranged from 100% to 90% across all the percentage concentrations. The lethal concentration also showed that the oxygen scavenger was more toxic than the defoamer, however, when they were combined;they showed an antagonistic relationship as the toxicity of the oxygen scavenger drastically reduced. The research findings intend to create awareness of the possible interaction of production chemicals when they are used for oil and gas activities and their combined toxicity contribution to produced water. This will in turn aid government regulators in their decision-making for disposal of produced water.