Two procedures were compared for extraction and clean-up of 20organophosphorus and 19 pyrethroid pesticides in sediment to identify the more effective procedurefor groups of pesticides or individual compounds. In Proc...Two procedures were compared for extraction and clean-up of 20organophosphorus and 19 pyrethroid pesticides in sediment to identify the more effective procedurefor groups of pesticides or individual compounds. In Procedure I, methanol/water and n-hexane wereused for extraction, and 1:10 (v/v) dichloromethane in n-hexane and acetone were used as eluents foreluting the analyte through the cartridge, with one evaporating steps on a rotary evaporator andtwo eluting steps on the cartridge. n-hexane/acetone (2:1, v/v) was used for extraction and elutionin Procedure II with one evaporating step on a rotary evaporator and one eluting step on thecartridge. All extractions were performed under an ultrasonic bath and gas chromatography and massspectrometry were utilized for measurements. Procedure II was developed as a rapid, timesaving, lesscostly and safer substitute for Procedure I which was an old method. Procedure II was moreeffective for almost all the organophosphorus pesticides tested and 11of the 19 pyrethroidpesticides, while Procedure I was more appropriate for analysis of 5 pyrethroid pesticides. However,recoveries of most pyrethroid pesticides were fairly low. Thus, further studies should focus onadjustment and formulation of solvents for more efficient extraction and clean-up of pyrethroidpesticides from sediment samples.展开更多
In this study the authors aimed to evaluate the oxidative stress enzymes indicative of liver damage in rats exposed to malathion （M）, subchronic form using cimetidine （C） and cimetidine plus malathion （M ＋ C）. ...In this study the authors aimed to evaluate the oxidative stress enzymes indicative of liver damage in rats exposed to malathion （M）, subchronic form using cimetidine （C） and cimetidine plus malathion （M ＋ C）. Malathion, widely used organophosphorus insecticide worldwide, induces oxidative liver damage type; cimetidine is an antagonist of histamine H2-receptor, it has been shown to be an inhibitor of various CYP45o isoforms. Male Wistar rats weighing 200-250 g were studied, exposed to malathion orally for 3 weeks （0.15 mg/kg/day, 2 mg/kg/day, 15 mg/kg/day） and cimetidine 10 mg/kg/day. Malathion plus cimetidine affect susceptibility to oxidative stress and possibly modifies the antioxidant defense capacity directly or indirectly.展开更多
The bulk ring-opening polymerization （ROP） of ε-caprolactone （ε-CL） by various phosphoric acids using phenylmethanol as the initiator was conducted. 1, 1＇-bi-2-Naphthol （BINOL）-based phosphoric acid was found...The bulk ring-opening polymerization （ROP） of ε-caprolactone （ε-CL） by various phosphoric acids using phenylmethanol as the initiator was conducted. 1, 1＇-bi-2-Naphthol （BINOL）-based phosphoric acid was found to be an effective organocatalyst for ROP leading to polyesters at 90℃. The overall conversion to poly（ε-caprolactone） was more than 96% and poly（ε-caprolactone） with Mw of 8400 and polydispersity index of 1.13 was obtained. IH NMR spectra of oligomers demonstrated the quantitative incorporation of the protic initiator in the polymer chains and showed that transesterification reactions did not occur to a significant extent. The controlled polymerization was indicated by the linear relationships between the number-average molar mass and monomer conversion or monomer-to-initiator ratio. In addition, the present protocol provided an easy-to-handle, inexpensive and environmentally benign entry for the synthesis of biodegradable materials as well as polyesters for biomedical applications.展开更多
Recent world events have emphasized the need to develop innovative, functional materials that will safely neutralize chemical warfare （CW） agents in situ to protect military personnel and civilians from dermal expos...Recent world events have emphasized the need to develop innovative, functional materials that will safely neutralize chemical warfare （CW） agents in situ to protect military personnel and civilians from dermal exposure. Here, we demonstrate the efficacy of a novel, proof-of-concept design for a Cu-containing catalyst, chemically bonded to a single-wall carbon nanotube （SWCNT） structural support, to effectively degrade an organophosphate simulant. SWCNTs have high tensile strength and are flexible and light-weight, which make them a desirable structural component for unique, fabric-like materials. This study aims to develop a self-decontaminating, carbon nanotube-derived material that can ultimately be incorporated into a wearable fabric or protective material to minimize dermal exposure to organophosphate nerve agents and to prevent accidental exposure during decontamination procedures. Carboxylated SWCNTs were functionalized with a polymer, which contained Cu-chelating bipyridine groups, and their catalytic activity against an organophosphate simulant was measured over time. The catalytically active, functionalized nanomaterial was characterized using X-ray fluorescence and Raman spectroscopy. Assuming zeroth-order reaction kinetics, the hydrolysis rate of the organophosphate simulant, as monitored by UV-vis absorption in the presence of the catalytically active nanomaterial, was 63 times faster than the uncatalyzed hydrolysis rate for a sample containing only carboxylated SWCNTs or a control sample containing no added nanotube materials.展开更多
基金Project supported by the Outstanding Youth Fund of National Natural Science Foundation of China, the National Key Basic Research Support Foundation (NKBRSF) of China (No. 2002CB410805) and the Federal Ministry of Education and Research, Germany.
文摘Two procedures were compared for extraction and clean-up of 20organophosphorus and 19 pyrethroid pesticides in sediment to identify the more effective procedurefor groups of pesticides or individual compounds. In Procedure I, methanol/water and n-hexane wereused for extraction, and 1:10 (v/v) dichloromethane in n-hexane and acetone were used as eluents foreluting the analyte through the cartridge, with one evaporating steps on a rotary evaporator andtwo eluting steps on the cartridge. n-hexane/acetone (2:1, v/v) was used for extraction and elutionin Procedure II with one evaporating step on a rotary evaporator and one eluting step on thecartridge. All extractions were performed under an ultrasonic bath and gas chromatography and massspectrometry were utilized for measurements. Procedure II was developed as a rapid, timesaving, lesscostly and safer substitute for Procedure I which was an old method. Procedure II was moreeffective for almost all the organophosphorus pesticides tested and 11of the 19 pyrethroidpesticides, while Procedure I was more appropriate for analysis of 5 pyrethroid pesticides. However,recoveries of most pyrethroid pesticides were fairly low. Thus, further studies should focus onadjustment and formulation of solvents for more efficient extraction and clean-up of pyrethroidpesticides from sediment samples.
文摘In this study the authors aimed to evaluate the oxidative stress enzymes indicative of liver damage in rats exposed to malathion （M）, subchronic form using cimetidine （C） and cimetidine plus malathion （M ＋ C）. Malathion, widely used organophosphorus insecticide worldwide, induces oxidative liver damage type; cimetidine is an antagonist of histamine H2-receptor, it has been shown to be an inhibitor of various CYP45o isoforms. Male Wistar rats weighing 200-250 g were studied, exposed to malathion orally for 3 weeks （0.15 mg/kg/day, 2 mg/kg/day, 15 mg/kg/day） and cimetidine 10 mg/kg/day. Malathion plus cimetidine affect susceptibility to oxidative stress and possibly modifies the antioxidant defense capacity directly or indirectly.
基金supported by the Fundamental Research Funds for the Central Universities (DL11CB06)
文摘The bulk ring-opening polymerization （ROP） of ε-caprolactone （ε-CL） by various phosphoric acids using phenylmethanol as the initiator was conducted. 1, 1＇-bi-2-Naphthol （BINOL）-based phosphoric acid was found to be an effective organocatalyst for ROP leading to polyesters at 90℃. The overall conversion to poly（ε-caprolactone） was more than 96% and poly（ε-caprolactone） with Mw of 8400 and polydispersity index of 1.13 was obtained. IH NMR spectra of oligomers demonstrated the quantitative incorporation of the protic initiator in the polymer chains and showed that transesterification reactions did not occur to a significant extent. The controlled polymerization was indicated by the linear relationships between the number-average molar mass and monomer conversion or monomer-to-initiator ratio. In addition, the present protocol provided an easy-to-handle, inexpensive and environmentally benign entry for the synthesis of biodegradable materials as well as polyesters for biomedical applications.
文摘Recent world events have emphasized the need to develop innovative, functional materials that will safely neutralize chemical warfare （CW） agents in situ to protect military personnel and civilians from dermal exposure. Here, we demonstrate the efficacy of a novel, proof-of-concept design for a Cu-containing catalyst, chemically bonded to a single-wall carbon nanotube （SWCNT） structural support, to effectively degrade an organophosphate simulant. SWCNTs have high tensile strength and are flexible and light-weight, which make them a desirable structural component for unique, fabric-like materials. This study aims to develop a self-decontaminating, carbon nanotube-derived material that can ultimately be incorporated into a wearable fabric or protective material to minimize dermal exposure to organophosphate nerve agents and to prevent accidental exposure during decontamination procedures. Carboxylated SWCNTs were functionalized with a polymer, which contained Cu-chelating bipyridine groups, and their catalytic activity against an organophosphate simulant was measured over time. The catalytically active, functionalized nanomaterial was characterized using X-ray fluorescence and Raman spectroscopy. Assuming zeroth-order reaction kinetics, the hydrolysis rate of the organophosphate simulant, as monitored by UV-vis absorption in the presence of the catalytically active nanomaterial, was 63 times faster than the uncatalyzed hydrolysis rate for a sample containing only carboxylated SWCNTs or a control sample containing no added nanotube materials.
