The Experts below are selected from a list of 93150 Experts worldwide ranked by ideXlab platform
Nancy G Doerrer - One of the best experts on this subject based on the ideXlab platform.
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a tiered approach to systemic toxicity testing for Agricultural Chemical safety assessment
Critical Reviews in Toxicology, 2006Co-Authors: John E Doe, Alan R Boobis, Ann M Blacker, Vicki L Dellarco, Nancy G Doerrer, Claire Franklin, Jay I Goodman, Joel M Kronenberg, Richard W Lewis, Ernest E McconnellAbstract:A proposal has been developed by the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) for an improved approach to assessing the safety of crop protection Chemicals. The goal is to ensure that studies are scientifically appropriate and necessary without being redundant, and that tests emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. The ACSA Systemic Toxicity Task Force proposes an approach to systemic toxicity testing as one part of the overall assessment of a compound's potential to cause adverse effects on health. The approach is designed to provide more relevant data for deriving reference doses for shorter time periods of human exposure, and includes fewer studies for deriving longer term reference doses-that is, neither a 12-month dog study nor a mouse carcinogenicity study is recommended. All available data, including toxicokinetics and metabolism data and life stages information, are taken into account. The proposed tiered testing approach has the potential to provide new risk assessment information for shorter human exposure durations while reducing the number of animals used and without compromising the sensitivity of the determination of longer term reference doses.
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a tiered approach to life stages testing for Agricultural Chemical safety assessment
Critical Reviews in Toxicology, 2006Co-Authors: Ralph L Cooper, Nancy G Doerrer, James C Lamb, Sue M Barlow, Karin S Bentley, Angela M Brady, David L Eisenbrandt, Penelope A Fennercrisp, Ronald N Hines, Lorraine IrvineAbstract:Aproposal has been developed by the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) for an improved approach to assessing the safety of crop protection Chemicals. The goal is to ensure that studies are scientifically appropriate and necessary without being redundant, and that tests emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. The ACSA Life Stages Task Force proposes a tiered approach to toxicity testing that assesses a compound's potential to cause adverse effects on reproduction, and that assesses the nature and severity of effects during development and adolescence, with consideration of the sensitivity of the elderly. While incorporating many features from current guideline studies, the proposed approach includes a novel rat reproduction and developmental study with enhanced endpoints and a rabbit development study. All available data, including toxicokinetics, ADMEdata, ...
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a tiered approach to life stages testing for Agricultural Chemical safety assessment
Critical Reviews in Toxicology, 2006Co-Authors: Ralph L Cooper, Nancy G Doerrer, James C Lamb, Sue M Barlow, Karin S Bentley, Angela M Brady, David L Eisenbrandt, Penelope A Fennercrisp, Ronald N Hines, Lorraine IrvineAbstract:A proposal has been developed by the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) for an improved approach to assessing the safety of crop protection Chemicals. The goal is to ensure that studies are scientifically appropriate and necessary without being redundant, and that tests emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. The ACSA Life Stages Task Force proposes a tiered approach to toxicity testing that assesses a compound's potential to cause adverse effects on reproduction, and that assesses the nature and severity of effects during development and adolescence, with consideration of the sensitivity of the elderly. While incorporating many features from current guideline studies, the proposed approach includes a novel rat reproduction and developmental study with enhanced endpoints and a rabbit development study. All available data, including toxicokinetics, ADME data, and systemic toxicity information, are considered in the design and interpretation of studies. Compared to existing testing strategies, the proposed approach uses fewer animals, provides information on the young animal, and includes an estimation of human exposure potential for making decisions about the extent of testing required.
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Agricultural Chemical safety assessment a multisector approach to the modernization of human safety requirements
Critical Reviews in Toxicology, 2006Co-Authors: Neil G Carmichael, John E Doe, Alan R Boobis, Vicki L Dellarco, Nancy G Doerrer, Ralph L Cooper, James C Lamb, Penelope A Fennercrisp, Hugh A Barton, Timothy P PastoorAbstract:Better understanding of toxicological mechanisms, enhanced testing capabilities, and demands for more sophisticated data for safety and health risk assessment have generated international interest in improving the current testing paradigm for Agricultural Chemicals. To address this need, the ILSI Health and Environmental Sciences Institute convened a large and diverse group of international experts to develop a credible and viable testing approach that includes scientifically appropriate studies that are necessary without being redundant, and that emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. Benefits of the proposed approach include improved data for risk assessment, greater efficiency, use of fewer animals, and better use of resources. From the outset of this endeavor, it was unanimously agreed that a tiered approach should be designed to incorporate existing knowledge on the chemistry, toxicology, and actual human exposure scenarios of the compound, wit...
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the acquisition and application of absorption distribution metabolism and excretion adme data in Agricultural Chemical safety assessments
Critical Reviews in Toxicology, 2006Co-Authors: Hugh A Barton, Nancy G Doerrer, Timothy P Pastoor, Karl Baetcke, Janice E Chambers, Janet J Diliberto, Jeffrey H Driver, Charles Hastings, Seshadri Iyengar, Robert I KriegerAbstract:A proposal has been developed by the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) for an improved approach to assessing the safety of crop protection Chemicals. The goal is to ensure that studies are scientifically appropriate and necessary without being redundant, and that tests emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. Incorporation of pharmacokinetic studies describing absorption, distribution, metabolism, and excretion is an essential tool for improving the design and interpretation of toxicity studies and their application for safety assessment. A tiered approach is described in which basic pharmacokinetic studies, similar to those for pharmaceuticals, are conducted for regulatory submission. Subsequent tiers provide additional information in an iterative manner, depending on pharmacokinetic properties, toxicity study results, and the intended uses of the compound.
Ralph L Cooper - One of the best experts on this subject based on the ideXlab platform.
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a tiered approach to life stages testing for Agricultural Chemical safety assessment
Critical Reviews in Toxicology, 2006Co-Authors: Ralph L Cooper, Nancy G Doerrer, James C Lamb, Sue M Barlow, Karin S Bentley, Angela M Brady, David L Eisenbrandt, Penelope A Fennercrisp, Ronald N Hines, Lorraine IrvineAbstract:Aproposal has been developed by the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) for an improved approach to assessing the safety of crop protection Chemicals. The goal is to ensure that studies are scientifically appropriate and necessary without being redundant, and that tests emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. The ACSA Life Stages Task Force proposes a tiered approach to toxicity testing that assesses a compound's potential to cause adverse effects on reproduction, and that assesses the nature and severity of effects during development and adolescence, with consideration of the sensitivity of the elderly. While incorporating many features from current guideline studies, the proposed approach includes a novel rat reproduction and developmental study with enhanced endpoints and a rabbit development study. All available data, including toxicokinetics, ADMEdata, ...
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a tiered approach to life stages testing for Agricultural Chemical safety assessment
Critical Reviews in Toxicology, 2006Co-Authors: Ralph L Cooper, Nancy G Doerrer, James C Lamb, Sue M Barlow, Karin S Bentley, Angela M Brady, David L Eisenbrandt, Penelope A Fennercrisp, Ronald N Hines, Lorraine IrvineAbstract:A proposal has been developed by the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) for an improved approach to assessing the safety of crop protection Chemicals. The goal is to ensure that studies are scientifically appropriate and necessary without being redundant, and that tests emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. The ACSA Life Stages Task Force proposes a tiered approach to toxicity testing that assesses a compound's potential to cause adverse effects on reproduction, and that assesses the nature and severity of effects during development and adolescence, with consideration of the sensitivity of the elderly. While incorporating many features from current guideline studies, the proposed approach includes a novel rat reproduction and developmental study with enhanced endpoints and a rabbit development study. All available data, including toxicokinetics, ADME data, and systemic toxicity information, are considered in the design and interpretation of studies. Compared to existing testing strategies, the proposed approach uses fewer animals, provides information on the young animal, and includes an estimation of human exposure potential for making decisions about the extent of testing required.
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Agricultural Chemical safety assessment a multisector approach to the modernization of human safety requirements
Critical Reviews in Toxicology, 2006Co-Authors: Neil G Carmichael, John E Doe, Alan R Boobis, Vicki L Dellarco, Nancy G Doerrer, Ralph L Cooper, James C Lamb, Penelope A Fennercrisp, Hugh A Barton, Timothy P PastoorAbstract:Better understanding of toxicological mechanisms, enhanced testing capabilities, and demands for more sophisticated data for safety and health risk assessment have generated international interest in improving the current testing paradigm for Agricultural Chemicals. To address this need, the ILSI Health and Environmental Sciences Institute convened a large and diverse group of international experts to develop a credible and viable testing approach that includes scientifically appropriate studies that are necessary without being redundant, and that emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. Benefits of the proposed approach include improved data for risk assessment, greater efficiency, use of fewer animals, and better use of resources. From the outset of this endeavor, it was unanimously agreed that a tiered approach should be designed to incorporate existing knowledge on the chemistry, toxicology, and actual human exposure scenarios of the compound, wit...
Lorraine Irvine - One of the best experts on this subject based on the ideXlab platform.
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a tiered approach to life stages testing for Agricultural Chemical safety assessment
Critical Reviews in Toxicology, 2006Co-Authors: Ralph L Cooper, Nancy G Doerrer, James C Lamb, Sue M Barlow, Karin S Bentley, Angela M Brady, David L Eisenbrandt, Penelope A Fennercrisp, Ronald N Hines, Lorraine IrvineAbstract:Aproposal has been developed by the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) for an improved approach to assessing the safety of crop protection Chemicals. The goal is to ensure that studies are scientifically appropriate and necessary without being redundant, and that tests emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. The ACSA Life Stages Task Force proposes a tiered approach to toxicity testing that assesses a compound's potential to cause adverse effects on reproduction, and that assesses the nature and severity of effects during development and adolescence, with consideration of the sensitivity of the elderly. While incorporating many features from current guideline studies, the proposed approach includes a novel rat reproduction and developmental study with enhanced endpoints and a rabbit development study. All available data, including toxicokinetics, ADMEdata, ...
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a tiered approach to life stages testing for Agricultural Chemical safety assessment
Critical Reviews in Toxicology, 2006Co-Authors: Ralph L Cooper, Nancy G Doerrer, James C Lamb, Sue M Barlow, Karin S Bentley, Angela M Brady, David L Eisenbrandt, Penelope A Fennercrisp, Ronald N Hines, Lorraine IrvineAbstract:A proposal has been developed by the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) for an improved approach to assessing the safety of crop protection Chemicals. The goal is to ensure that studies are scientifically appropriate and necessary without being redundant, and that tests emphasize toxicological endpoints and exposure durations that are relevant for risk assessment. The ACSA Life Stages Task Force proposes a tiered approach to toxicity testing that assesses a compound's potential to cause adverse effects on reproduction, and that assesses the nature and severity of effects during development and adolescence, with consideration of the sensitivity of the elderly. While incorporating many features from current guideline studies, the proposed approach includes a novel rat reproduction and developmental study with enhanced endpoints and a rabbit development study. All available data, including toxicokinetics, ADME data, and systemic toxicity information, are considered in the design and interpretation of studies. Compared to existing testing strategies, the proposed approach uses fewer animals, provides information on the young animal, and includes an estimation of human exposure potential for making decisions about the extent of testing required.
Feng Zhou - One of the best experts on this subject based on the ideXlab platform.
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facile preparation of n alkyl 2 pyrrolidones in a continuous flow microreactor
Organic Process Research & Development, 2018Co-Authors: Feng Zhou, Boyu Zhang, Hongchen Liu, Zhenghui Wen, Kejun Wang, Guangwen ChenAbstract:N-Alkyl-2-pyrrolidones have been widely used in the petroChemical industry, the Agricultural Chemical industry, electronic materials, etc. The distinct advantages of using N-alkyl-2-pyrrolidones as solvents or reaction media make them particularly important. A continuous-flow microreactor was exploited for the preparation of N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP) in a highly controlled and safe manner; thus, its use improved the efficiency of the process. Various conditions (temperature, residence time, molar ratio of amine to γ-butyrolactone (GBL), GBL concentration, water content, and presence of H3BO3 catalyst) were investigated to improve the synthesis of NMP/NEP. A microreactor was employed for the conversion of GBL to NMP and NEP, and the yields reached 94.7% for NMP and 93.9% for NEP under the optimized conditions. Furthermore, a kinetic model based on the reaction mechanism was proposed to guide the design and optimization of the synthesis of NMP/NEP.
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Facile Preparation of N‑Alkyl-2-pyrrolidones in a Continuous-Flow Microreactor
2018Co-Authors: Feng Zhou, Boyu Zhang, Hongchen Liu, Zhenghui Wen, Kejun Wang, Guangwen ChenAbstract:N-Alkyl-2-pyrrolidones have been widely used in the petroChemical industry, the Agricultural Chemical industry, electronic materials, etc. The distinct advantages of using N-alkyl-2-pyrrolidones as solvents or reaction media make them particularly important. A continuous-flow microreactor was exploited for the preparation of N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP) in a highly controlled and safe manner; thus, its use improved the efficiency of the process. Various conditions (temperature, residence time, molar ratio of amine to γ-butyrolactone (GBL), GBL concentration, water content, and presence of H3BO3 catalyst) were investigated to improve the synthesis of NMP/NEP. A microreactor was employed for the conversion of GBL to NMP and NEP, and the yields reached 94.7% for NMP and 93.9% for NEP under the optimized conditions. Furthermore, a kinetic model based on the reaction mechanism was proposed to guide the design and optimization of the synthesis of NMP/NEP
Thomas B. Moorman - One of the best experts on this subject based on the ideXlab platform.
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biodegradation of atrazine by agrobacterium radiobacter j14a and use of this strain in bioremediation of contaminated soil
Applied and Environmental Microbiology, 1998Co-Authors: J. K Struthers, Krish Jayachandran, Thomas B. MoormanAbstract:We examined the ability of a soil bacterium, Agrobacterium radiobacter J14a, to degrade the herbicide atrazine under a variety of cultural conditions, and we used this bacterium to increase the biodegradation of atrazine in soils from Agricultural Chemical distribution sites. J14a cells grown in nitrogen-free medium with citrate and sucrose as carbon sources mineralized 94% of 50 μg of [14C-U-ring]atrazine ml−1 in 72 h with a concurrent increase in the population size from 7.9 × 105 to 5.0 × 107 cells ml−1. Under these conditions cells mineralized the [ethyl-14C]atrazine and incorporated approximately 30% of the 14C into the J14a biomass. Cells grown in medium without additional carbon and nitrogen sources degraded atrazine, but the cell numbers did not increase. Metabolites produced by J14a during atrazine degradation include hydroxyatrazine, deethylatrazine, and deethyl-hydroxyatrazine. The addition of 105 J14a cells g−1 into soil with a low indigenous population of atrazine degraders treated with 50 and 200 μg of atrazine g−1 soil resulted in two to five times higher mineralization than in the noninoculated soil. Sucrose addition did not result in significantly faster mineralization rates or shorten degradation lag times. However, J14a introduction (105 cells g−1) into another soil with a larger indigenous atrazine-mineralizing population reduced the atrazine degradation lag times below those in noninoculated treatments but did not generally increase total atrazine mineralization.
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biodegradation of atrazine by agrobacterium radiobacter j14a and use of this strain in bioremediation of contaminated soil
Applied and Environmental Microbiology, 1998Co-Authors: J. K Struthers, Krish Jayachandran, Thomas B. MoormanAbstract:Use of atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in the United States was estimated in 1991 to be 34 to 41 million kilograms annually (30). Contamination of soil from pesticide mixing, loading, storage, and rinsing at Agricultural Chemical dealerships in the Midwest is a concern due to potential contamination of surface water and groundwater. The U.S. Environmental Protection Agency (EPA) reported that atrazine has been found in the groundwater of approximately 25 states due to both point and nonpoint sources. In a 1987 study of Iowa public water systems, 16 of the 18 wells with detections of pesticides, including atrazine, were located within 1,000 feet of an Agricultural Chemical dealership (12). High levels of pesticides and nitrate in soils, surface water, and groundwater were found at 28 dealerships in Iowa, with maximum atrazine concentrations of 1,100 μg g−1 in soil, 16 μg liter−1 in surface water, and 1,500 μg liter−1 in groundwater (14), which are well above the U.S. EPA maximum contaminant level of 3 μg liter−1 for drinking water. Low-cost strategies for bioremediation of atrazine and other pesticides in soil and groundwater at agriChemical dealership sites are needed. The degradation of atrazine occurs predominantly by biological processes, including N-dealkylation, dechlorination, and ring cleavage. Atrazine biodegradation can be initiated by N-dealkylation of the ethyl or isopropyl side chains to produce deethylatrazine (DEA) or deisopropylatrazine (DIA) (3, 6, 22–24). Dechlorination has been reported as an early step in atrazine metabolism (6, 20), and two different s-triazine hydrolase enzymes (11, 25) have been characterized. In some microorganisms, complete biodegradation of atrazine to ammonia and CO2 has been obtained (19, 28, 32). These previous studies show a wide variation in the kinetics and extent of atrazine degradation and the ability of bacteria to grow on atrazine. In addition, the stimulatory or inhibitory effects of additional carbon or nitrogen sources on atrazine degradation varies among the bacteria described in the literature. An understanding of these factors is necessary in order to improve the effectiveness of these bacteria in bioremediation applications. Previous studies have shown that atrazine-degrading bacteria applied as single strains or as consortia can increase degradation of atrazine in soil, but these treatments vary in their effectiveness. Soil contaminated with 1,500 μg of atrazine g−1 was inoculated with the Pseudomonas strain ADP, resulting in the degradation of approximately 17% of the atrazine (19). Addition of citrate to the soil increased the degradation to 70% of the aged atrazine. Addition of a Pseudomonas strain resulted in mineralization of over 60% of 10 μg of atrazine g−1 soil in 49 days and an atrazine half-life of 1 day (33). However, the addition of the same strain to another low-pH soil and a soil with a high organic-matter content resulted in much slower atrazine degradation, with half-lives of 19 and 22 days, respectively. Mixed cultures of microorganisms have also increased the biodegradation of atrazine when added to soils containing relatively small amounts of atrazine (3, 4). The objectives of the present study were to determine the factors that govern the atrazine biodegradation by a newly isolated bacterium and to determine its potential effectiveness in degrading atrazine in soil. We describe here the isolation and characterization of Agrobacterium radiobacter J14a, a strain which is capable of utilizing atrazine as a sole nitrogen source. Experiments were also conducted to determine the effects of secondary carbon and nitrogen substrates on atrazine degradation in culture and in soils contaminated with atrazine.