The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Cheng Ding - One of the best experts on this subject based on the ideXlab platform.
-
kinetic analysis and degradation pathway for m Dichlorobenzene removal by brevibacillus agri dh 1 and its performance in a biotrickling filter
Bioresource Technology, 2017Co-Authors: Bairen Yang, Zhuqiu Sun, Liping Wang, Cheng DingAbstract:Abstract A strain, Brevibacillus agri DH-1, isolated from dry lands was used to remove m -Dichlorobenzene. After 48 h culturing, the concentrations of m -Dichlorobenzene decreased from 26–130 to 7.87–28.87 mg/L and dry cell weight for bacterial growth reached 52.43–75.05 mg/L. The growth and degradation kinetics were analyzed by the fitting of Haldane-Andrews model and pseudo first-order model. A degradation pathway was proposed according to major intermediates (phenol), chloride ion variation, ring-opening enzyme activity, and high mineralization (0.47 g Cl- /g m -Dichlorobenzene , 0.65 g co2 /g m -Dichlorobenzene , 0.15 g DCW /g m -Dichlorobenzene ). In addition, the performance in a biotrickling filter (BTF) was evaluated through removal efficiency and pressure drop values with increasing inlet loading rate from 4.10 to 122.57 g/m 3 /h at three empty bed residence time points (30 s, 60 s, and 90 s). The results demonstrated that strain DH-1 possessed high removal efficiency and stable operation in a BTF.
-
Influence of 1,2-Dichlorobenzene on Anaerobic Microorganisms in Wetland Soil
Advanced Materials Research, 2013Co-Authors: Hui Xing Liang, Ai Hui Chen, Cheng Ding, Zhao Xia LiAbstract:The potential effect of 1,2-Dichlorobenzene (1,2-DCB) on anaerobic microbial populations was investigated in a flooded wetland soil. Numbers of anaerobic fermentative bacteria (AFB), denitrifying bacteria (DNB) and hydrogen-producing acetogenic bacteria (HPAB) were numerated by three-tube anaerobic most-probable-number (MPN) methods with anaerobic liquid enrichment media. In anaerobic microbe groups, the changes of bacterium group were not the same. 1,2-Dichlorobenzene had the maximum influence on microbial groups of wetland soil at the initial pollution. In dealing with 14-35 days, bacterium groups in each processing soil have different amplitude bouncing back. In the experimental process, bacteria which produces hydrogen and acetic acid is most sensitive to 1,2-Dichlorobenzene. Hydrolysis fermentation bacteria second, and denitrifying bacteria was the smallest.
-
Isolation, Identification and Degradation Characterization of 1,2-Dichlorobenzene Degrading Strain
2010 4th International Conference on Bioinformatics and Biomedical Engineering, 2010Co-Authors: Chunsheng Yang, Zhao Xia Li, Cheng Ding, Hui Xing LiangAbstract:A bacterium(strain DL-1) capable of growing with 1,2-Dichlorobenzene as sole carbon and energy sources was isolated from rhizosphere soil in phragmites wetland by using the enrichment culture contaminated with 1,2-Dichlorobenzene concentration gradient of 20, 40, 60, 80, 120, 160 and 200 mg·L-1. It was identified as Bacillus cereus by 16S rDNA gene sequence analysis and the bacterial culture characteristics, carried physiological and biochemical research, the strain was Gram-positive, peritrichous flagellum. The further degrading characterization research proved the strain was a facultative anaerobe and the optimal temperature, pH value and inoculation amount of 1,2-Dichlorobenzene degradation were 30°C, pH7.0 and 10%, in 4 d. Respectively , the optimal concentration of 1,2-Dichlorobenzene in four days was 120 mg·L-1.
-
Treatment of 1,2-Dichlorobenzene in Pilot-Scale Constructed Wetlands
2010 4th International Conference on Bioinformatics and Biomedical Engineering, 2010Co-Authors: Chunsheng Yang, Cheng DingAbstract:Three pilot-scale horizontal subsurface flow CWs of different soil substrates planted with Phragmites australis were installed and operated for field investigations on the removal of 1,2-Dichlorobenzene in simulated wastewater. The optimal HRT was determined at 5 days when the mean removal efficiencies of 1,2-Dichlorobenzene in loam, coarse sand and fine sand CWs were 90%,78% and 77% respectively. The systems carried out for 3 months from summer to autumn and relatively more steady treatment efficiency was observed in loam or coarse sand CWs than that of fine sand CW, which was declining all the time. Spatial concentration dynamics of 1,2-Dichlorobenzene and oxygen were investigated in relation to the distance from the inflow and the depth of the wetland bed, which revealed that oxygen concentration was an important factor for 1,2-Dichlorobenzene removal.
I. Glenn Sipes - One of the best experts on this subject based on the ideXlab platform.
-
Comparative metabolism and toxicity of Dichlorobenzenes in Sprague-Dawley, Fischer-344 and human liver slices:
Human & experimental toxicology, 1995Co-Authors: Robyn L. Fisher, I. Glenn Sipes, A. Jay Gandolfi, Steven J. Hasal, Klaus BrendelAbstract:1. Precision-cut liver slices, prepared from Sprague-Dawley and Fischer-344 rats and donated human liver tissue, were used to identify differences in 1,2-Dichlorobenzene (1,2-DCB), 1,3-Dichlorobenzene (1,3-DCB) and 1,4-Dichlorobenzene (1,4-DCB) metabolism and how it may relate to toxicity. 2. Rat and human liver slices were incubated with 1 mM of either Dichlorobenzene to determine metabolism and toxicity, at 2 and 6 h of organ culture. 3. The human liver slices metabolised the Dichlorobenzenes to a greater extent than those from either of the rat strains. Liver slices from the Fischer-344 strain had a higher metabolic rate than the slices from the Sprague-Dawley rat strain. 4. The metabolic rate of Dichlorobenzene isomers did not consistently correlate with its toxicity. For example, human slices did not exhibit any hepatoxicity, even though they metabolised these compounds to a greater extent than either rat strain. 5. Cross species covalent binding did not correlate with toxicity endpoints measured in this study. 6. The phase two metabolite profiles for each of the isomers in human and rat slices were similar in that the glutathione-cysteine conjugate was the major metabolite. 7. The use of an in vitro system which utilises human liver slices might provide an important bridge between animal derived data and the human situation.
-
In-vitro hepatotoxicity of three Dichlorobenzene isomers in human liver slices.
Human & experimental toxicology, 1991Co-Authors: Robyn L. Fisher, John Barr, Charles F. Zukoski, Charles W. Putnam, I. Glenn Sipes, A. Jay Gandolfi, Klaus BrendelAbstract:1 The cytotoxicity of Dichlorobenzenes in cultured rat liver slices has previously been shown to be strain specific and biotransformation related. 2 In order to extrapolate animal models to humans, the Dichlorobenzenes were incubated with human liver slices to try to clarify their hepatotoxic potential in man. 3 The degree of hepatotoxicity observed with the Dichlorobenzenes depended on whether Waymouth's or Krebs-Henseleit was used as the incubation medium. 4 All three Dichlorobenzenes (1 mM) produced no significant differences from control when incubated in Waymouth's medium. However, in the Krebs-Henseleit buffer there was a substantial increase in cytotoxicity. 5 In both incubation mediums the Dichlorobenzene isomers exhibited the following rank order 1,3-DCB greater than 1,2-DCB greater than 1,4-DCB. 6 1,2-Dichlorobenzene hepatotoxicity was blocked by metyrapone, 1,3-Dichlorobenzene toxicity was blocked by SKF 525-A and neither one of these inhibitors could block the 1,4-Dichlorobenzene cytotoxicity. 7 The use of human liver tissues to evaluate potential toxicants merits consideration since the hepatotoxicity of xenobiotics and drugs in man is the ultimate question.
-
Dichlorobenzene hepatotoxicity strain differences and structure activity relationships.
Advances in experimental medicine and biology, 1991Co-Authors: L. Gunawardhana, I. Glenn SipesAbstract:Environmentally significant halogenated compounds include the three isomers of Dichlorobenzene (DCB), i.e. ortho (1,2-DCB), meta (1,3-DCB) and para (1,4-DCB), which have been identified as contaminants in air and water at sites throughout the United States (United States Environmental Protection Agency, 1985). This environmental contamination by the Dichlorobenzenes reflects their wide-spread use in industry. These compounds are extensively used as solvents, fumigants and intermediates in the production of pesticides and dyes (Hawley, 1971).
Klaus Brendel - One of the best experts on this subject based on the ideXlab platform.
-
Comparative metabolism and toxicity of Dichlorobenzenes in Sprague-Dawley, Fischer-344 and human liver slices:
Human & experimental toxicology, 1995Co-Authors: Robyn L. Fisher, I. Glenn Sipes, A. Jay Gandolfi, Steven J. Hasal, Klaus BrendelAbstract:1. Precision-cut liver slices, prepared from Sprague-Dawley and Fischer-344 rats and donated human liver tissue, were used to identify differences in 1,2-Dichlorobenzene (1,2-DCB), 1,3-Dichlorobenzene (1,3-DCB) and 1,4-Dichlorobenzene (1,4-DCB) metabolism and how it may relate to toxicity. 2. Rat and human liver slices were incubated with 1 mM of either Dichlorobenzene to determine metabolism and toxicity, at 2 and 6 h of organ culture. 3. The human liver slices metabolised the Dichlorobenzenes to a greater extent than those from either of the rat strains. Liver slices from the Fischer-344 strain had a higher metabolic rate than the slices from the Sprague-Dawley rat strain. 4. The metabolic rate of Dichlorobenzene isomers did not consistently correlate with its toxicity. For example, human slices did not exhibit any hepatoxicity, even though they metabolised these compounds to a greater extent than either rat strain. 5. Cross species covalent binding did not correlate with toxicity endpoints measured in this study. 6. The phase two metabolite profiles for each of the isomers in human and rat slices were similar in that the glutathione-cysteine conjugate was the major metabolite. 7. The use of an in vitro system which utilises human liver slices might provide an important bridge between animal derived data and the human situation.
-
In-vitro hepatotoxicity of three Dichlorobenzene isomers in human liver slices.
Human & experimental toxicology, 1991Co-Authors: Robyn L. Fisher, John Barr, Charles F. Zukoski, Charles W. Putnam, I. Glenn Sipes, A. Jay Gandolfi, Klaus BrendelAbstract:1 The cytotoxicity of Dichlorobenzenes in cultured rat liver slices has previously been shown to be strain specific and biotransformation related. 2 In order to extrapolate animal models to humans, the Dichlorobenzenes were incubated with human liver slices to try to clarify their hepatotoxic potential in man. 3 The degree of hepatotoxicity observed with the Dichlorobenzenes depended on whether Waymouth's or Krebs-Henseleit was used as the incubation medium. 4 All three Dichlorobenzenes (1 mM) produced no significant differences from control when incubated in Waymouth's medium. However, in the Krebs-Henseleit buffer there was a substantial increase in cytotoxicity. 5 In both incubation mediums the Dichlorobenzene isomers exhibited the following rank order 1,3-DCB greater than 1,2-DCB greater than 1,4-DCB. 6 1,2-Dichlorobenzene hepatotoxicity was blocked by metyrapone, 1,3-Dichlorobenzene toxicity was blocked by SKF 525-A and neither one of these inhibitors could block the 1,4-Dichlorobenzene cytotoxicity. 7 The use of human liver tissues to evaluate potential toxicants merits consideration since the hepatotoxicity of xenobiotics and drugs in man is the ultimate question.
-
Metabolism of Dichlorobenzenes in organ cultured liver slices.
Advances in experimental medicine and biology, 1991Co-Authors: Robyn L. Fisher, S. Mccarthy, I. G. Sipes, R. P. Hanzlik, Klaus BrendelAbstract:A novel in vitro system was used to evaluate tissue specific toxicity. This system utilizes precision cut organ slices in dynamic organ culture and is viable for up to 24 hrs. The three isomers of Dichlorobenzene were added to liver slices prepared from Sprague Dawley rats or human donors. The precursor Dichlorobenzenes were radiolabelled and metabolites were separated by classes (i.e. glucuronides, sulfates and glutathione and cysteine conjugates). Covalent Binding of the Dichlorobenzenes was also determined after extensive extraction of the tissue. The total amount of metabolism of the Dichlorobenzenes varied depending on the isomer and the type of tissue. For example, the Sprague-Dawley rat liver slices metabolized 1,2-DCB and 1,3-DCB at approximately the same rate while 1,4-DCB was metabolized at a slower rate. This metabolism profile was also seen in the majority of the adult human liver slices. However, the fetal human slices showed that 1,4-DCB was metabolized to a greater extent than 1,3-DCB or 1,2-DCB while 1,3-DCB was metabolized at a faster rate than 1,2-DCB. Our results show that liver slices in organ culture are a suitable system for species comparisons and of structure/activity relationships in xenobiotic metabolism with an emphasis on the fate of reactive intermediates. In addition, this system is suitable for evaluation of hepatotoxic potency.
Adam Krajewski - One of the best experts on this subject based on the ideXlab platform.
-
Preliminary research on mortality of wood destroying Anobiidae (Coleoptera) following the application of p-Dichlorobenzene in combination with low oxygen atmosphere fumigation
Polish Journal of Entomology, 2018Co-Authors: Aleksandra Wójcik, Adam KrajewskiAbstract:Abstract Experiments were undertaken in connection with the need, indicated in the literature, for the proper choice of a substance enhancing the effect of a low oxygen atmosphere used as a means of controlling wood boring insects in museum collections and historical objects. A low oxygen atmosphere itself causes the death of wood boring insects after a relatively long period of application. Thus, attempts were made to use p-Dichlorobenzene to accelerate the effects of a low oxygen atmosphere in the control of wood boring insects. The experiments were performed as a continuation of preliminary research on the effect of p-Dichlorobenzene on Anobiidae in an aerobic atmosphere. The paper present the results of gassing Anobium punctatum and Ptilinus pectinicornis (Coleoptera: Anobiidae) larvae with 1,4-Dichlorobenzene in a low oxygen atmosphere of nitrogen and argon. The experiments were performed in laboratory conditions at a temperature of 20°C on larvae extracted from wood. The results do not show a faster elimination of larvae of either species using p-Dichlorobenzene in a low oxygen atmosphere as compared to using p-Dichlorobenzene in an aerobic atmosphere. Complete eradication of larvae in the test groups was obtained after 48 hours when using p-Dichlorobenzene in nitrogen. The results obtained when using p-Dichlorobenzene in argon appear to be worse at fumigation times shorter than 48 hours.
-
Preliminary research on mortality of wood destroying Anobiidae (Coleoptera) following the application of p-Dichlorobenzene in combination with low oxygen atmosphere fumigation
Polish Journal of Entomology, 2018Co-Authors: Aleksandra Wójcik, Adam KrajewskiAbstract:Abstract Experiments were undertaken in connection with the need, indicated in the literature, for the proper choice of a substance enhancing the effect of a low oxygen atmosphere used as a means of controlling wood boring insects in museum collections and historical objects. A low oxygen atmosphere itself causes the death of wood boring insects after a relatively long period of application. Thus, attempts were made to use p-Dichlorobenzene to accelerate the effects of a low oxygen atmosphere in the control of wood boring insects. The experiments were performed as a continuation of preliminary research on the effect of p-Dichlorobenzene on Anobiidae in an aerobic atmosphere. The paper present the results of gassing Anobium punctatum and Ptilinus pectinicornis (Coleoptera: Anobiidae) larvae with 1,4-Dichlorobenzene in a low oxygen atmosphere of nitrogen and argon. The experiments were performed in laboratory conditions at a temperature of 20°C on larvae extracted from wood. The results do not show a faster elimination of larvae of either species using p-Dichlorobenzene in a low oxygen atmosphere as compared to using p-Dichlorobenzene in an aerobic atmosphere. Complete eradication of larvae in the test groups was obtained after 48 hours when using p-Dichlorobenzene in nitrogen. The results obtained when using p-Dichlorobenzene in argon appear to be worse at fumigation times shorter than 48 hours.
Jalal Hassan - One of the best experts on this subject based on the ideXlab platform.
-
trace analysis of chlorobenzenes in water samples using headspace solvent microextraction and gas chromatography electron capture detection
Talanta, 2006Co-Authors: Mostafa Khajeh, Yadollah Yamini, Jalal HassanAbstract:Abstract In the present work, a rapid method for the extraction and determination of chlorobenzenes (CBs) such as monochlorobenzene, 1,2-Dichlorobenzene, 1,3-Dichlorobenzene, 1,4-Dichlorobenzene, 1,2,3-trichlorobenzene and 1,2,4-trichlorobenzene in water samples using the headspace solvent microextraction (HSME) and gas chromatography/electron capture detector (ECD) has been described. A microdrop of the dodecane containing monobromobenzene (internal standard) was used as extracting solvent in this investigation. The analytes were extracted by suspending a 2.5 μl extraction drop directly from the tip of a microsyringe fixed above an extraction vial with a septum in a way that the needle passed through the septum and the needle tip appeared above the surface of the solution. After the extraction was finished, the drop was retracted back into the needle and injected directly into a GC column. Optimization of experimental conditions such as nature of the extracting solvent, microdrop and sample temperatures, stirring rate, microdrop and sample volumes, the ionic strength and extraction time were investigated. The optimized conditions were as follows: dodecane as the extracting solvent, the extraction temperature, 45 °C; the sodium chloride concentration, 2 M; the extraction time, 5.0 min; the stirring rate, 500 rpm; the drop volume, 2.5 μl; the sample volume, 7 ml; the microsyringe needle temperature, 0.0 °C. The limit of detection (LOD) ranged from 0.1 μg/l (for 1,3-Dichlorobenzene) to 3.0 μg/l (for 1,4-Dichlorobenzene) and linear range of 0.5–3.0 μg/l for 1,2-Dichlorobenzene, 1,3-Dichlorobenzene and from 5.0 to 20.0 μg/l for monochlorobenzene and from 5.0 to 30 μg/l for 1,4-Dichlorobenzene. The relative standard deviations (R.S.D.) for most of CBs at the 5 μg/l level were below 10%. The optimized procedure was successfully applied to the extraction and determination of CBs in different water samples.