Using carbon tetrachloride (CCl4) as extraction agent, the activated sludge from Tianjin Jizhuangzi Sewage Treatment Plant as inoculum, the test study on biodegradability of lubricants was carried out. The test flas...Using carbon tetrachloride (CCl4) as extraction agent, the activated sludge from Tianjin Jizhuangzi Sewage Treatment Plant as inoculum, the test study on biodegradability of lubricants was carried out. The test flasks containing the mineral medium, the test oil and the inoculum were placed in incubation together with flasks containing poisoned blanks for periods of 0 and 21 days, respectively. Flasks containing the reference materials in place of the test oil were run in parallel. At the end of the incubation period, the contents of the flasks were subjected to sonic vibration, and were acidified and extracted by using CCI4. The extracts were then analysed by infra-red (IR) spectrometer to measure the maximum absorption of the C-H stretch of CH2-CH3 band at wavelength of 2 930 cm^-1. The absorption values were used to calculate the residual oil contents of the poisoned and test flasks. Consequently the biodegradability of the test oil was calculated. The test results indicate that the differences in the biodegradability of test materials in different tests are within 5.5%, and consistent with the data described in Coordinating European Council (CEC) L-33- A-93. The biodegradability of lubricants can be evaluated by this method effectively.展开更多
An inter-laboratory comparison of the AOAC mouse bioassay for paralytic shellfish poisoning (PSP) toxicity in shellfish was carried out among 25 Chinese laboratories to examine the overall performance for PSP testing ...An inter-laboratory comparison of the AOAC mouse bioassay for paralytic shellfish poisoning (PSP) toxicity in shellfish was carried out among 25 Chinese laboratories to examine the overall performance for PSP testing in China, and to analyze the main factors affecting the performance of this method. The toxic scallop Patinopecten yessoensis collected from coast of Bohai Sea, China, was used as a test sample in the comparison study. The results were reported and evaluated using robust statistical methods. The z scores showed that 80%, 8%, and 12% of laboratories reported satisfactory results, unsatisfactory results, and questionable results, respectively. This evaluation demonstrates that the PSP mouse bioassay is an appropriate method for screening and testing PSP toxicity in shellfish. However, it was found that the experience and skill of technicians, as well as the body weight and health status of mice being used significantly affected the accuracy of the method.展开更多
Allelopathy was defined in 1996 by IAS (international allelopathy society) as any process involving secondary metabolites produced by plant, algae, bacteria and fungi that influences the growth and development of ag...Allelopathy was defined in 1996 by IAS (international allelopathy society) as any process involving secondary metabolites produced by plant, algae, bacteria and fungi that influences the growth and development of agricultural and biological systems. Rice allelopathy against weeds was reported since 1989, which offers an integrated weed management with substantially reduced herbicide usage. Application of allelopathic rice cultivars is thought a resources conservation and environmental friendly way of weed bio-control, and could promote the sustainable development of agriculture. Screening or evaluating the allelopathic potential rice variety is the first step. In this paper, a new bioassay method was set up by the allelopathic potential of 9 rice lines on the target weed barnyardgrass (Echinochloa crusgalli), and comparing with bioassay methods such as relay seeding in filter paper (RSF) and relay seeding in agar (RSA). The results indicated that three methods had a same tendency in evaluating the allelopathic potential of rice; there existed a significant difference among different bioassay methods, and an interaction between bioassay methods and rice lines. The method of root exudates (RE) with the highest value and a correlation efficiency of 0.98 was considered as ideal bioassay method for evaluation of allelopathic potential.展开更多
The behavior of schools of zebrafish (Danio rerio) was studied in acute toxicity environments. Behavioral features were extracted and a method for water quality assessment using support vector machine (SVM) was de...The behavior of schools of zebrafish (Danio rerio) was studied in acute toxicity environments. Behavioral features were extracted and a method for water quality assessment using support vector machine (SVM) was de- veloped. The behavioral parameters of fish were recorded and analyzed during one hour in an environment of a 24-h half-lethal concentration (LC50) of a pollutant. The data were used to develop a method to evaluate water quality, so as 6+ 2+ to give an early indication of toxicity. Four kinds of metal ions (Cu2~, Hg2~, Cr , and Cd ) were used for toxicity testing. To enhance the efficiency and accuracy of assessment, a method combining SVM and a genetic algorithm (GA) was used. The results showed that the average prediction accuracy of the method was over 80% and the time cost was acceptable. The method gave satisfactory results for a variety of metal pollutants, demonstrating that this is an effective approach to the classification of water quality.展开更多
Trace element-contaminated soils(TECSs) are one of the consequences of the past industrial development worldwide. Excessive exposure to trace elements(TEs) represents a permanent threat to ecosystems and humans worldw...Trace element-contaminated soils(TECSs) are one of the consequences of the past industrial development worldwide. Excessive exposure to trace elements(TEs) represents a permanent threat to ecosystems and humans worldwide owing to the capacity of metal(loid)s to cross the cell membranes of living organisms and of human epithelia, and their interference with cell metabolism.Quantification of TE bioavailability in soils is complicated due to the polyphasic and reactive nature of soil constituents. To unravel critical factors controlling soil TE bioavailability and to quantify the ecological toxicity of TECSs, TEs are pivotal for evaluating excessive exposure or deficiencies and controlling the ecological risks. While current knowledge on TE bioavailability and related cumulative consequences is growing, the lack of an integrated use of this concept still hinders its utilization for a more holistic view of ecosystem vulnerability and risks for human health. Bioavailability is not generally included in models for decision making in the appraisal of TECS remediation options. In this review we describe the methods for determining the TE bioavailability and technological developments, gaps in current knowledge, and research needed to better understand how TE bioavailability can be controlled by sustainable TECS management altering key chemical properties, which would allow policy decisions for environmental protection and risk management.展开更多
In this paper, for time-to-event data, we propose a new statistical framework for casual inference in evaluating clinical utility of predictive biomarkers and in selecting an optimal treatment for a particular patient...In this paper, for time-to-event data, we propose a new statistical framework for casual inference in evaluating clinical utility of predictive biomarkers and in selecting an optimal treatment for a particular patient. This new casual framework is based on a new concept, called Biomarker Adjusted Treatment Effect (BATE) curve. The BATE curve can be used for assessing clinical utility of a predictive biomarker, for designing a subsequent confirmation trial, and for guiding clinical practice. We then propose semi-p^rametric methods for estimating the BATE curves of biomarkers and establish asymptotic results of the proposed estimators for the BATE curves. We also conduct extensive simulation studies to evaluate finite-sample properties of the proposed estimation methods. Finally, we illustrate the application of the proposed method in a real-world data set.展开更多
A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional e...A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass(Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT(CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt(Na2EDTA)- and acetic acid(HOAc)-extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perenne was negatively influenced by p H and positively influenced by organic matter(OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA- and HOAc-extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were p H and OM dependent. For CE, the relationship was p H independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability.展开更多
基金China Petroleum & Chemical Corporation (No. 104141)
文摘Using carbon tetrachloride (CCl4) as extraction agent, the activated sludge from Tianjin Jizhuangzi Sewage Treatment Plant as inoculum, the test study on biodegradability of lubricants was carried out. The test flasks containing the mineral medium, the test oil and the inoculum were placed in incubation together with flasks containing poisoned blanks for periods of 0 and 21 days, respectively. Flasks containing the reference materials in place of the test oil were run in parallel. At the end of the incubation period, the contents of the flasks were subjected to sonic vibration, and were acidified and extracted by using CCI4. The extracts were then analysed by infra-red (IR) spectrometer to measure the maximum absorption of the C-H stretch of CH2-CH3 band at wavelength of 2 930 cm^-1. The absorption values were used to calculate the residual oil contents of the poisoned and test flasks. Consequently the biodegradability of the test oil was calculated. The test results indicate that the differences in the biodegradability of test materials in different tests are within 5.5%, and consistent with the data described in Coordinating European Council (CEC) L-33- A-93. The biodegradability of lubricants can be evaluated by this method effectively.
基金Supported by a thesis research project of General Administration of Quality Supervision, Inspection and Quarantine of China (No. 2010IK168)
文摘An inter-laboratory comparison of the AOAC mouse bioassay for paralytic shellfish poisoning (PSP) toxicity in shellfish was carried out among 25 Chinese laboratories to examine the overall performance for PSP testing in China, and to analyze the main factors affecting the performance of this method. The toxic scallop Patinopecten yessoensis collected from coast of Bohai Sea, China, was used as a test sample in the comparison study. The results were reported and evaluated using robust statistical methods. The z scores showed that 80%, 8%, and 12% of laboratories reported satisfactory results, unsatisfactory results, and questionable results, respectively. This evaluation demonstrates that the PSP mouse bioassay is an appropriate method for screening and testing PSP toxicity in shellfish. However, it was found that the experience and skill of technicians, as well as the body weight and health status of mice being used significantly affected the accuracy of the method.
文摘Allelopathy was defined in 1996 by IAS (international allelopathy society) as any process involving secondary metabolites produced by plant, algae, bacteria and fungi that influences the growth and development of agricultural and biological systems. Rice allelopathy against weeds was reported since 1989, which offers an integrated weed management with substantially reduced herbicide usage. Application of allelopathic rice cultivars is thought a resources conservation and environmental friendly way of weed bio-control, and could promote the sustainable development of agriculture. Screening or evaluating the allelopathic potential rice variety is the first step. In this paper, a new bioassay method was set up by the allelopathic potential of 9 rice lines on the target weed barnyardgrass (Echinochloa crusgalli), and comparing with bioassay methods such as relay seeding in filter paper (RSF) and relay seeding in agar (RSA). The results indicated that three methods had a same tendency in evaluating the allelopathic potential of rice; there existed a significant difference among different bioassay methods, and an interaction between bioassay methods and rice lines. The method of root exudates (RE) with the highest value and a correlation efficiency of 0.98 was considered as ideal bioassay method for evaluation of allelopathic potential.
基金Project supported by the Natural Science Foundation of Ningbo City (No.2010A610005)the Key Science and Technology Program of Zhejiang Province (No.2011C11049),China
文摘The behavior of schools of zebrafish (Danio rerio) was studied in acute toxicity environments. Behavioral features were extracted and a method for water quality assessment using support vector machine (SVM) was de- veloped. The behavioral parameters of fish were recorded and analyzed during one hour in an environment of a 24-h half-lethal concentration (LC50) of a pollutant. The data were used to develop a method to evaluate water quality, so as 6+ 2+ to give an early indication of toxicity. Four kinds of metal ions (Cu2~, Hg2~, Cr , and Cd ) were used for toxicity testing. To enhance the efficiency and accuracy of assessment, a method combining SVM and a genetic algorithm (GA) was used. The results showed that the average prediction accuracy of the method was over 80% and the time cost was acceptable. The method gave satisfactory results for a variety of metal pollutants, demonstrating that this is an effective approach to the classification of water quality.
基金financially supported by the European Research Area Network (ERA-NET) Sustainable Management of Soil and Groundwater Under the Pressure of Pollution and Contamination (SNOWMAN) Project Sustainable Management of Trace Element Contaminated Soils (SuMaTECS)
文摘Trace element-contaminated soils(TECSs) are one of the consequences of the past industrial development worldwide. Excessive exposure to trace elements(TEs) represents a permanent threat to ecosystems and humans worldwide owing to the capacity of metal(loid)s to cross the cell membranes of living organisms and of human epithelia, and their interference with cell metabolism.Quantification of TE bioavailability in soils is complicated due to the polyphasic and reactive nature of soil constituents. To unravel critical factors controlling soil TE bioavailability and to quantify the ecological toxicity of TECSs, TEs are pivotal for evaluating excessive exposure or deficiencies and controlling the ecological risks. While current knowledge on TE bioavailability and related cumulative consequences is growing, the lack of an integrated use of this concept still hinders its utilization for a more holistic view of ecosystem vulnerability and risks for human health. Bioavailability is not generally included in models for decision making in the appraisal of TECS remediation options. In this review we describe the methods for determining the TE bioavailability and technological developments, gaps in current knowledge, and research needed to better understand how TE bioavailability can be controlled by sustainable TECS management altering key chemical properties, which would allow policy decisions for environmental protection and risk management.
基金supported by a Core Investigator,Research Career Scientist(Grant No.RCS OS-196)Biostatistics Unit Director at the Northwest HSR&D Center of Excellence,Department of Veterans Affairs Medical Center,Seattle,WA and Department of Veterans Affairs,Veterans Health Administration,Health Services Research and Development Service,project(Grant No.XVA61-036)
文摘In this paper, for time-to-event data, we propose a new statistical framework for casual inference in evaluating clinical utility of predictive biomarkers and in selecting an optimal treatment for a particular patient. This new casual framework is based on a new concept, called Biomarker Adjusted Treatment Effect (BATE) curve. The BATE curve can be used for assessing clinical utility of a predictive biomarker, for designing a subsequent confirmation trial, and for guiding clinical practice. We then propose semi-p^rametric methods for estimating the BATE curves of biomarkers and establish asymptotic results of the proposed estimators for the BATE curves. We also conduct extensive simulation studies to evaluate finite-sample properties of the proposed estimation methods. Finally, we illustrate the application of the proposed method in a real-world data set.
基金supported by the China Postdoctoral Science Foundation (No. 2013M530783)the Research Foundation for Advanced Talents of Qingdao Agricultural University, China (No. 6631115029)
文摘A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass(Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT(CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt(Na2EDTA)- and acetic acid(HOAc)-extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perenne was negatively influenced by p H and positively influenced by organic matter(OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA- and HOAc-extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were p H and OM dependent. For CE, the relationship was p H independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability.