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Sample records for carbamic acid phenylmethyl

  1. Carbamic acid and carbamate formation in NH{3}:CO{2} ices - UV irradiation versus thermal processes

    Science.gov (United States)

    Bossa, J. B.; Theulé, P.; Duvernay, F.; Borget, F.; Chiavassa, T.

    2008-12-01

    Context: We study carbamic acid [ NH{2}COOH] and ammonium carbamate [ NH{2}COO-] [ NH{4}+] formation in interstellar ice analogs. Aims: We demonstrate how carbamic acid [ NH{2}COOH] and ammonium carbamate [ NH{2}COO-] [ NH{4}+] can be formed from both thermal reactions and energetic photons in an NH{3}:CO{2} ice mixture. Methods: Infrared and mass spectroscopy are used to monitor NH{3}:CO{2} ice mixture evolution during both warming and VUV photon irradiation. Results: Carbamic acid and ammonium carbamate can be produced thermally in a 1:1 ratio from NH{3} and CO{2} above 80 K. They can be also formed in a 28:1 ratio by less efficient processes such as energetic photons. Our study and its results provide fresh insight into carbamic acid formation in interstellar ices. Conclusions: We demonstrate that care is required to separate irradiation-induced reactivity from purely thermal reactivity in ices in which ammonia and carbon dioxide are both present. From an interstellar chemistry point of view, carbamic acid and ammonium carbamate are readily produced from the ice mantle of a typical interstellar grain and should therefore be a detectable species in molecular clouds.

  2. Amino Acid Carbamates As Prodrugs Of Resveratrol.

    Science.gov (United States)

    Mattarei, Andrea; Azzolini, Michele; La Spina, Martina; Zoratti, Mario; Paradisi, Cristina; Biasutto, Lucia

    2015-01-01

    Resveratrol (3, 5, 4'-trihydroxy-trans-stilbene), a plant polyphenol, has important drug-like properties, but its pharmacological exploitation in vivo is hindered by its rapid transformation via phase II conjugative metabolism. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, stability and in vivo pharmacokinetic behaviour of prodrugs of resveratrol in which the OH groups are engaged in an N-monosubstituted carbamate ester (-OC(O)NHR) linkage with a natural amino acid (Leu, Ile, Phe, Thr) to prevent conjugation and modulate the physicochemical properties of the molecule. We also report a convenient, high-yield protocol to obtain derivatives of this type. The new carbamate ester derivatives are stable at pH 1, while they undergo slow hydrolysis at physiological pH and hydrolyse with kinetics suitable for use in prodrugs in whole blood. After administration to rats by oral gavage the isoleucine-containing prodrug was significantly absorbed, and was present in the bloodstream as non-metabolized unaltered or partially deprotected species, demonstrating effective shielding from first-pass metabolism. We conclude that prodrugs based on the N-monosubstituted carbamate ester bond have the appropriate stability profile for the systemic delivery of phenolic compounds. PMID:26463125

  3. Amino Acid Carbamates As Prodrugs Of Resveratrol

    OpenAIRE

    Andrea Mattarei; Michele Azzolini; Martina La Spina; Mario Zoratti; Cristina Paradisi; Lucia Biasutto

    2015-01-01

    Resveratrol (3, 5, 4′-trihydroxy-trans-stilbene), a plant polyphenol, has important drug-like properties, but its pharmacological exploitation in vivo is hindered by its rapid transformation via phase II conjugative metabolism. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, stability and in vivo pharmacokinetic behaviour of prodrugs of resveratrol in which the OH groups are engaged in an N-monosubstituted carbamate ester (-OC(O)NHR) lin...

  4. Efficient Lewis Acids Catalyzed Aza-Michael Reactions of Enones with Carbamates

    Institute of Scientific and Technical Information of China (English)

    XIA Chun-Gu; XU Li-Wen

    2004-01-01

    The a-amino carbonyl functionality is not only a segment of biologically important natural products but also a versatile intermediate for the synthesis of nitrogen-containing compounds.1 The development of novel synthetic methods leading to a-amino ketone, a-amino acids or their derivatives has attracted much attention in organic synthesis.2 Among the traditional methods for generating a-amino carbonyl compounds, Mannich-type reaction is one of the classical and powerful methods.3 However, the classic Mannich reaction presents serious disadvantages, for example, there is still a drawback in that the silyl enolates have to be prepared from the corresponding carbonyl compounds. Alternatively, aza-Michael additions can be used to create carbon-heteroatom bonds by reaction of a,a-unsaturated carbonyl compounds with amines. Although recent advances have made this route more attractive, development of cheaper, simpler, and more efficient metal catalyst, especially which can be applied to chalcone, is highly desirable.In this paper, we demonstrated that the first aza-Michael reaction of chalcone with a less nucleophilic carbamates can be accomplished on Me3SiCFFeCl3 catalyst system under very mild conditions. Apart from experimental simplicity, the advantages of this methodology are the use of a very cheap Lewis acid catalyst and the insensitivity of the reaction mixture towards air and moisture.catalyst for aza-Michael reaction of chalcone and cyclic enones with carbamates. And with the cyclic enones with carbamates in dichloromethane at room temperature were also investigated. In this conjugate addition reaction, good to excellent yields of a-amino ketones were obtained with system could also mediates aza-Michael addition of carbamates to chalcone and derivatives.These new strategies opened efficient procedures for the synthesis of a-amino ketones under mild conditions.

  5. Crystal structures of carbamate kinase from Giardia lamblia bound with citric acid and AMP-PNP.

    Directory of Open Access Journals (Sweden)

    Kap Lim

    Full Text Available The parasite Giardia lamblia utilizes the L-arginine dihydrolase pathway to generate ATP from L-arginine. Carbamate kinase (CK catalyzes the last step in this pathway, converting ADP and carbamoyl phosphate to ATP and ammonium carbamate. Because the L-arginine pathway is essential for G. lamblia survival and absent in high eukaryotes including humans, the enzyme is a potential target for drug development. We have determined two crystal structures of G. lamblia CK (glCK with bound ligands. One structure, in complex with a nonhydrolyzable ATP analog, adenosine 5'-adenylyl-β,γ-imidodiphosphate (AMP-PNP, was determined at 2.6 Å resolution. The second structure, in complex with citric acid bound in the postulated carbamoyl phosphate binding site, was determined in two slightly different states at 2.1 and 2.4 Å resolution. These structures reveal conformational flexibility of an auxiliary domain (amino acid residues 123-170, which exhibits open or closed conformations or structural disorder, depending on the bound ligand. The structures also reveal a smaller conformational change in a region associated the AMP-PNP adenine binding site. The protein residues involved in binding, together with a model of the transition state, suggest that catalysis follows an in-line, predominantly dissociative, phosphotransfer reaction mechanism, and that closure of the flexible auxiliary domain is required to protect the transition state from bulk solvent.

  6. Isotope separation of carbon-13 by counter-current column with exchange reaction between carbon dioxide and carbamic acid

    International Nuclear Information System (INIS)

    The isotope separation performance of carbon-13 with exchange reaction between CO2 and carbamic acid was studied and some factors for the counter-current column were studied for improving the overall performance. The working fluid for the experiments was a solution of DNBA, (C4H9)2NH, and n-octane mixture. The rate-controlling step of 13C transfer at temperatures higher than 10 deg C was the exchange reaction between carbamic acid and CO2 dissolved by physical absorption. The capacity coefficient of 13C transfer between gas and liquid in the counter-current column was successfully related to the product of three factors: the concentration of carbamic acid, the concentration of CO2 dissolved by physical absorption and the liquid holdup of the column. The liquid holdup was also an important factor. As the holdup increased, the isotope exchange rate and the overall separation factor of the column increased. However, the transient time to equilibrium was much longer. (author)

  7. Evaluation of exposure to organophosphate, carbamate, phenoxy acid, and chlorophenol pesticides in pregnant women from 10 Caribbean countries.

    Science.gov (United States)

    Forde, Martin S; Robertson, Lyndon; Laouan Sidi, Elhadji A; Côté, Suzanne; Gaudreau, Eric; Drescher, Olivia; Ayotte, Pierre

    2015-09-01

    Pesticides are commonly used in tropical regions such as the Caribbean for both household and agricultural purposes. Of particular concern is exposure during pregnancy, as these compounds can cross the placental barrier and interfere with fetal development. The objective of this study was to evaluate exposure of pregnant women residing in 10 Caribbean countries to the following commonly used classes of pesticides in the Caribbean: organophosphates (OPs), carbamates, phenoxy acids, and chlorophenols. Out of 438 urine samples collected, 15 samples were randomly selected from each Caribbean country giving a total of 150 samples. Samples were analyzed for the following metabolites: six OP dialkylphosphate metabolites [dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate (DEP), diethylthiophosphate (DETP) and diethyldithiophosphate (DEDTP)]; two carbamate metabolites [2-isopropoxyphenol (2-IPP) and carbofuranphenol]; one phenoxy acid 2,4-dichlorophenoxyacetic acid (2,4-D); and five chlorophenols [2,4-dichlorophenol (DCP), 2,5-dichlorophenol (2,5-DCP), 2,4,5-trichlorophenol (TCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP)]. OP metabolites were consistently detected in ≥60% of the samples from Antigua and Barbuda, Bermuda, and Jamaica. Of the carbamate metabolites, 2-IPP was detected in seven of the 10 Caribbean countries with a detection frequency around 30%, whereas carbofuranphenol was detected in only one sample. The detection frequency for the phenoxy acid 2,4-D ranged from 20% in Grenada to a maximum of 67% in Belize. Evidence of exposure to chlorophenol pesticides was also established with 2,4-DCP by geometric means ranging from 0.52 μg L(-1) in St Lucia to a maximum of 1.68 μg L(-1) in Bermuda. Several extreme concentrations of 2,5-DCP were detected in four Caribbean countries-Belize (1100 μg L(-1)), Bermuda (870 μg L(-1)), Jamaica (1300 μg L(-1)), and St Kitts and Nevis (1400 μg L(-1

  8. Synthesis, screening for antiacetylcholinesterase activity and binding mode prediction of a new series of [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Zanatta, Nilo; Marchi, Tiago M.; Bonacorso, Helio G.; Martins, Marcos A.P.; Flores, Alex F.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica. Nucleo de Quimica de Heterociclos]. E-mail: zanatta@base.ufsm.br; Borchhardt, Deise M.; Andricopulo, Adriano D.; Salum, Livia B. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Centro de Biotecnologia Molecular Estrutural. Lab. de Quimica Medicinal e Computacional; Carpes, Adriana D.; Schetinger, Maria R.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica. Lab. de Enzimologia Toxicologica

    2008-07-01

    A series of nine new [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters (phosphate-carbamate compounds) was obtained through the reaction of (4,4,4-trifluoro-3-hydroxybut-1-yl)-carbamic acid ethyl esters with phosphorus oxychloride followed by the addition of alcohols. The products were characterized by {sup 1}H, {sup 13}C, {sup 31}P, and {sup 19}F NMR spectroscopy, GC-MS, and elemental analysis. All the synthesized compounds were screened for acetylcholinesterase (AChE) inhibitory activity using the Ellman method. All compounds containing phosphate and carbamate pharmacophores in their structures showed enzyme inhibition, being the compound bearing the diethoxy phosphate group (2b) the most active compound. Molecular modeling studies were performed to investigate the detailed interactions between AChE active site and small-molecule inhibitor candidates, providing valuable structural insights into AChE inhibition. (author)

  9. Allergic reaction induced by dermal and/or respiratory exposure to low-dose phenoxyacetic acid, organophosphorus, and carbamate pesticides

    International Nuclear Information System (INIS)

    Several types of pesticides, such as organophosphates, phenoxyacetic acid, and carbamate have a high risk of affecting human health, causing allergic rhinitis and bronchial asthma-like diseases. We used our long-term sensitization method and a local lymph node assay to examine the allergic reactions caused by several types of pesticides. BALB/c mice were topically sensitized (9 times in 3 weeks), then challenged dermally or intratracheally with 2,4-D, BRP, or furathiocarb. One day post-challenge, the mice were processed to obtain biologic materials for use in assays of total IgE levels in serum and bronchoalveolar lavage fluid (BALF); differential cell counts and chemokine levels in BALF; lymphocyte counts and surface antigen expression on B-cells within regional lymph nodes (LNs); and, ex situ cytokine production by cells from these LNs. 2,4-D-induced immune responses characteristic of immediate-type respiratory reactions, as evidenced by increased total IgE levels in both serum and BALF; an influx of eosinophils, neutrophils, and chemokines (MCP-1, eotaxin, and MIP-1β) in BALF; increased surface antigen expression on B-cells IgE and MHC class II production) in both auricular and the lung-associated LNs; and increased Th2 cytokine production (IL-4, IL-5, IL-10, and IL-13) in both auricular and the lung-associated LN cells. In contrast, BRP and furathiocarb treatment yielded, at most, non-significant increases in all respiratory allergic parameters. BRP and furathiocarb induced marked proliferation of MHC Class II-positive B-cells and Th1 cytokines (IL-2, TNF-α, and IFN-γ) in only auricular LN cells. These results suggest that 2,4-D is a respiratory allergen and BRP and furathiocarb are contact allergens. As our protocol detected classified allergic responses to low-molecular-weight chemicals, it thus may be useful for detecting environmental chemical-related allergy.

  10. Assessing the Potential Content of Ethyl Carbamate in White, Red, and Rosé Wines as a Key Factor for Pursuing Urea Degradation by Purified Acid Urease.

    Science.gov (United States)

    Cerreti, Martina; Fidaleo, Marcello; Benucci, Ilaria; Liburdi, Katia; Tamborra, Pasquale; Moresi, Mauro

    2016-07-01

    The ethyl carbamate (EC) content of a wine after a given temperature-time storage was theoretically predicted from the potential concentration of ethyl carbamate (PEC), as determined via an accelerated EC formation test. Such information was used to decide whether an enzymatic treatment was needed to reduce the wine urea level before bottling/aging. To this end, 6 white, red, and rosé wines, manufactured in Italy as such or enriched with urea, were tested for their PEC content either before or after enzymatic treatment using a purified acid urease preparation derived from Lactobacillus fermentum. The treatment was severely affected by the total phenolic content (TP) of the wine, the estimated pseudo-first-order kinetic rate constant for NH3 formation reducing by a factor of approximately 2000 as the TP increased from 0 to 1.64 g L(-1) . Such a sensitivity to TP was by far greater than that pertaining to a killed cell-based enzyme preparation used previously. Urea hydrolysis was successful at reducing EC concentration in wines with low levels of TP and other EC precursors. PMID:27239804

  11. Chemoselective Synthesis of Carbamates using CO2 as Carbon Source.

    Science.gov (United States)

    Riemer, Daniel; Hirapara, Pradipbhai; Das, Shoubhik

    2016-08-01

    Synthesis of carbamates directly from amines using CO2 as the carbon source is a straightforward and sustainable approach. Herein, we describe a highly effective and chemoselective methodology for the synthesis of carbamates at room temperature and atmospheric pressure. This methodology can also be applied to protect the amino group in amino acids and peptides, and also to synthesize important pharmaceuticals. PMID:27376902

  12. Comparative MO investigation of hindered rotation and thermal decomposition of carbamates and thiocarbamates

    International Nuclear Information System (INIS)

    Investigation of hindered rotation in carbamates reveals the high flexibility and ionic character of the C-N bond as compared to common amides. This flexibility decreases in the case of thiocarbamates. The mechanism of activation of carbamates has been explored. Computations have proven the possibility of formation of an intramolecular H-bond in carbamates and thiocarbamates. This intramolecular H-bond is formed immediately after protonation of the carbamate. The possibility of formation of zwitterions as intermediates in the decomposition of carbamic and dithiocarbamic acids is discussed. (Auth.)

  13. Determination of Neurotoxin b-ODAP and Non-protein Amino Acids in Lathyrus Sativus by High-Performance Liquid Chromatography with Precolumn Derivatization with 6-Amino quinolyl-N-hydroxysuccinimidyl Carbamate (AQC)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new method was developed for the quantitative determination of the neurotoxic non-protein amino acid, 3-N-oxalyl-L-2,3-diaminopropionic acid (b -ODAP), its nontoxic a -isomer and other non-protein amino acids in the plant samples of Lathyrus sativus after derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) by reversed-phase high-performance liquid chromatography (HPLC). 2-Amino butyric acid (ABA) was used as an internal standard. The RP HPLC detection limit for both isomers is 1.8 ng with good response linearity. The results are compared with a colorimetric method.

  14. Select small core structure carbamates exhibit high contact toxicity to "carbamate-resistant" strain malaria mosquitoes, Anopheles gambiae (Akron.

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    Dawn M Wong

    Full Text Available Acetylcholinesterase (AChE is a proven target for control of the malaria mosquito (Anopheles gambiae. Unfortunately, a single amino acid mutation (G119S in An. gambiae AChE-1 (AgAChE confers resistance to the AChE inhibitors currently approved by the World Health Organization for indoor residual spraying. In this report, we describe several carbamate inhibitors that potently inhibit G119S AgAChE and that are contact-toxic to carbamate-resistant An. gambiae. PCR-RFLP analysis was used to confirm that carbamate-susceptible G3 and carbamate-resistant Akron strains of An. gambiae carry wild-type (WT and G119S AChE, respectively. G119S AgAChE was expressed and purified for the first time, and was shown to have only 3% of the turnover number (k(cat of the WT enzyme. Twelve carbamates were then assayed for inhibition of these enzymes. High resistance ratios (>2,500-fold were observed for carbamates bearing a benzene ring core, consistent with the carbamate-resistant phenotype of the G119S enzyme. Interestingly, resistance ratios for two oxime methylcarbamates, and for five pyrazol-4-yl methylcarbamates were found to be much lower (4- to 65-fold. The toxicities of these carbamates to live G3 and Akron strain An. gambiae were determined. As expected from the enzyme resistance ratios, carbamates bearing a benzene ring core showed low toxicity to Akron strain An. gambiae (LC(50>5,000 μg/mL. However, one oxime methylcarbamate (aldicarb and five pyrazol-4-yl methylcarbamates (4a-e showed good to excellent toxicity to the Akron strain (LC(50 = 32-650 μg/mL. These results suggest that appropriately functionalized "small-core" carbamates could function as a resistance-breaking anticholinesterase insecticides against the malaria mosquito.

  15. Antitumor Effect of the Mannich Base(1,3-bis-((3-Hydroxynaphthalen-2-yl)phenylmethyl)urea) on Hepatocellular Carcinoma.

    Science.gov (United States)

    Vedarethinam, Vadanasundari; Dhanaraj, Karthik; Ilavenil, Soundharrajan; Arasu, Mariadhas Valan; Choi, Ki Choon; Al-Dhabi, Naif Abdullah; Srisesharam, Srigopalram; Lee, Kyung Dong; Kim, Da Hye; Dhanapal, Tamilvenvendan; Sivanesan, Ravikumar; Choi, Han Sung; Kim, Young Ock

    2016-01-01

    The present study was designed to evaluate the antitumor effects of the synthetic Mannich base 1,3-bis-((3-hydroxynaphthalen-2-yl)phenylmethyl)urea (1,3-BPMU) against HEP-G2 hepatoma cells and diethylnitrosamine (DEN)-induced hepatocarcinoma (HCC) in albino rats. In vitro analysis results revealed that 1,3-BPMU showed significant cytotoxicity and cell growth inhibition in HEP-G2 hepatoma cells in a concentration-dependent manner. Furthermore, flow cytometry results indicated that 1,3-BPMU enhanced early and late apoptosis. The maximum apoptosis was exhibited at a concentration of 100 μg/mL of 1,3-BPMU. In in vivo analysis, DEN treatment increased the content of nucleic acids, LPO and the activities of AST, ALT, ALP, LDH, γGT and 5'NT with decreased antioxidant activity as compared to control rats. However, 1,3-BPMU treatment to DEN-induced rats decreased the content of nucleic acids, LPO and the activities of AST, ALT, ALP, LDH, γGT and 5'NT and increased the activities of SOD, CAT, GPx, GST and GR (p < 0.05). Furthermore, 1,3-BPMU enhanced the apoptosis via upregulation of caspase-3 and caspase-9 and the downregulation of Bcl-2 and Bcl-XL mRNA expression as compared to DEN-induced rats. Histological and ultrastructural investigation showed that 1,3-BPMU treatment renovated the internal architecture of the liver in DEN-induced rats. In this study, the molecular and pre-clinical results obtained by treatment of DEN-induced rats with 1,3-BPMU suggested that 1,3-BPMU might be considered as an antitumor compound in the future. PMID:27187346

  16. Ethyl-bridged hybrid column as an efficient alternative for HPLC analysis of plasma amino acids by pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate.

    Science.gov (United States)

    Castellanos, Mar; Van Eendenburg, Cecile Van; Gubern, Carme; Sanchez, Juan M

    2016-09-01

    Conventional C18 silica columns have proven to be useful for the analysis of amino acids (AA) from protein hydrolysates but undesirable peak overlapping is usually found when analyzing body fluids given that a large number of AAs are present in the samples. As an alternative to silica packings, an ethyl-bridged packing for reversed-phase liquid chromatography of derivatized AAs with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) has been evaluated. The new packing material improves the separation efficiency allowing better separations when analyzing biological fluids. Moreover, this packing has advantages for routine AA analysis, such as a decrease in the total running time and an increase in the life-time of the columns. The pH of the mobile phase has a significant effect on the elution behavior of the AQC hydrolysis product (AMQ) and on the AA derivatives. It is not possible to elute AMQ before detecting the first AA derivative, which requires an accurate adjustment of the pH in the range of 5.30-5.35 to obtain good separation and resolution for the most polar compounds. Under the conditions proposed, it is possible to separate all AAs except the Gly-Gln pair, which is not a problem when hydrolyzed samples are analyzed. The AMQ-Ser pair requires either the use of a different mobile phase pH for its baseline separation or the use of fluorescence detection. Two different procedures for protein removal from plasma samples have been evaluated, solvent precipitation and ultrafiltration (UF) and it has been found that UF gives better results as no significant losses of AAs were observed. The validation of the proposed method with UV detection gives method detection limits in the range of 8-12μM, with repeatability values<8% (n=6) and inter-day precision in plasma samples ranging from 4 to 13% (n=4). PMID:27428457

  17. Physicochemical studies of the carbamate-CO2-solvent system

    International Nuclear Information System (INIS)

    The formation of carbamate from CO2 and the various amine solutions has been investigated for the purpose of elucidating the structure of the species generated in the reaction. The amine solutions used were 1 and 2 molar solutions of di-n-butylamine (DNBA) in triethylamine (TEA), pure DNBA and pure TEA. It has been found that the nonaqueous solvent participates in the formation of carbamate in 1 and 2M-DNBA/TEA solutions as a proton acceptor in DNBA-carbamate formation. However, due to the high concentration of the solutions and the basicities of the amines, a significant amount of DNBA which does not form the DNBA-carbamate anion is also found to be participating as a proton acceptor. Pure TEA absorbs only 1/60 of the absorption by pure DNBA. The extent of TEA participation in the CO2-absorption process other than as a proton acceptor in DNBA-carbamate is negligible. The formation of carbamic acid and zwitterion have been found unlikely. 7 tables, 15 figs

  18. Photoinduced chemiluminescence determination of carbamate pesticides.

    Science.gov (United States)

    Catalá-Icardo, M; Meseguer-Lloret, S; Torres-Cartas, S

    2016-05-11

    A liquid chromatography method with post-column photoinduced chemiluminescence (PICL) detection is proposed for the simultaneous determination of eight carbamate pesticides, namely aldicarb, butocarboxim, ethiofencarb, methomyl, methiocarb, thiodicarb, thiofanox and thiophanate-methyl. After chromatographic separation, quinine (sensitizer) was incorporated and the flow passed through an UV lamp (67 s of irradiation time) to obtain the photoproducts, which reacted with acidic Ce(iv) and provided a CL emission. The PICL method showed great selectivity for carbamate pesticides containing sulphur in their chemical structure. A solid-phase extraction process increased sensitivity (LODs ranging from 0.06 to 0.27 ng mL(-1)) and allowed the carbamate pesticides in surface and ground water samples to be determined, with recoveries in the range 87-110% (except for thiophanate-methyl, whose recoveries were between 60 and 75%). The intra- and inter-day precision was evaluated, with RSD ranging from 1.1 to 7.5% and from 2.6 to 12.3%, respectively. A discussion about the PICL mechanism is also included. PMID:27079156

  19. Subchronic Toxicity Study in Rats of Two New Ethyl-Carbamates with Ixodicidal Activity

    Directory of Open Access Journals (Sweden)

    María Guadalupe Prado-Ochoa

    2014-01-01

    Full Text Available Female and male Wistar rats were used to determine the subchronic oral toxicities of two new ethyl-carbamates with ixodicidal activities (ethyl-4-bromphenyl-carbamate and ethyl-4-chlorphenyl-carbamate. The evaluated carbamates were administered in the drinking water (12.5, 25 and 50 mg/kg/day for 90 days. Exposure to the evaluated carbamates did not cause mortality or clinical signs and did not affect food consumption or weight gain. However, exposure to these carbamates produced alterations in water consumption, hematocrit, percentages of reticulocytes, plasma proteins, some biochemical parameters (aspartate aminotransferase, gamma-glutamyl transpeptidase, cholinesterase, and creatinine activities, thiobarbituric acid reactive substances, and the relative weight of the spleen. Histologically, slight pathological alterations were found in the liver that were consistent with the observed biochemical alterations. The nonobserved adverse effect levels (NOAELs of the evaluated carbamates were 12.5 mg/kg/day for both the female and male rats. The low severity and reversibility of the majority of the observed alterations suggest that the evaluated carbamates have low subchronic toxicity.

  20. Vinyl carbamate epoxide, a major strong electrophilic, mutagenic and carcinogenic metabolite of vinyl carbamate and ethyl carbamate (urethane).

    Science.gov (United States)

    Park, K K; Liem, A; Stewart, B C; Miller, J A

    1993-03-01

    Vinyl carbamate epoxide (VCO) was found to possess strong electrophilic, mutagenic and carcinogenic activities. It reacted with water at 37 degrees C and pH 7.4 (phosphate buffer) to form glycolaldehyde and several related reducing compounds; none of these products were mutagenic for Salmonella typhimurium TA1535. Under these conditions VCO had a half-life (determined chemically and mutagenically) of approximately 10.5 min. This half-life was progressively lowered by increasing concentrations of chloride ion (liver, serum and isotonic levels). This ion reacted with VCO to form chloroacetaldehyde. VCO also reacted with other nucleophiles such as glutathione, DNA and its constituent guanine and adenine bases. The purine adducts formed by VCO in DNA in vitro and in vivo were released by weak acid treatment and consisted of 7-(2'-oxoethyl)guanine and N2,3-ethenoguanine as major products with 1,N6-ethenoadenine as a minor product. VCO was a strong direct mutagen in Salmonella typhimurium TA1535 and TA100 but was only weakly active in the TA98 mutant. VCO was a stronger initiator of carcinogenesis in the skin of CD-1 mice and in the liver of infant male B6C3F1 mice than its metabolic precursors vinyl carbamate (VC) and ethyl carbamate (EC). Unlike VC and EC, VCO was a strong complete carcinogen in the skin of CD-1 mice and induced papillomas and carcinomas following repetitive administration of sub-ulcerogenic doses. VCO also exhibited some carcinogenic activity in the lungs of mice and in the s.c. and mammary tissue of female Sprague-Dawley rats. These data and those from other recent studies support the conclusion that VCO is a major strong electrophilic, mutagenic and carcinogenic metabolite of EC and VC in the mouse. PMID:8453720

  1. New synthesis of carbamate, thiocarbamate and urea type herbicides: preparation of 14C-labelled diuron and EPTC

    International Nuclear Information System (INIS)

    N,N-dialkyl-carbamic acid-trimethylsilyl-esters were synthesized starting with 14CO2. The new synthesis route is simple and provides good radiochemical yield. Silyl-carbaminates directly or through carbamoyl-halogenides may be used for preparation of labelled herbicides: carbamates, thiocarbamates and ureas. (author)

  2. Antitumor Effect of the Mannich Base(1,3-bis-((3-Hydroxynaphthalen-2-yl)phenylmethyl)urea) on Hepatocellular Carcinoma

    OpenAIRE

    Vadanasundari Vedarethinam; Karthik Dhanaraj; Soundharrajan Ilavenil; Mariadhas Valan Arasu; Ki Choon Choi; Naif Abdullah Al-Dhabi; Srigopalram Srisesharam; Kyung Dong Lee; Da Hye Kim; Tamilvenvendan Dhanapal; Ravikumar Sivanesan; Han Sung Choi; Young Ock Kim

    2016-01-01

    The present study was designed to evaluate the antitumor effects of the synthetic Mannich base 1,3-bis-((3-hydroxynaphthalen-2-yl)phenylmethyl)urea (1,3-BPMU) against HEP-G2 hepatoma cells and diethylnitrosamine (DEN)-induced hepatocarcinoma (HCC) in albino rats. In vitro analysis results revealed that 1,3-BPMU showed significant cytotoxicity and cell growth inhibition in HEP-G2 hepatoma cells in a concentration-dependent manner. Furthermore, flow cytometry results indicated that 1,3-BPMU enh...

  3. The Target of Benzimidazole Carbamate Against Cysticerci cellulosae

    Institute of Scientific and Technical Information of China (English)

    LI Qing-zhang; HAO Yan-hong; GAO Xue-jun; GAO Wen-xue; ZHAO Bing

    2007-01-01

    To study the target of benzimidazole carbamate drugs against Cysticerci cellulosae and give a theoretical basis for type evolution and new drug design, the changes of key enzyme activities and metabolite contents in the pathway of energy metabolism in C. cellulosae in vitro and in vivo were tested with albendazole and oxfendazole, respectively. Both albendazole and oxfendazole inhibited the pathways of anaerobic glycolysis, partial inversed tricarboxylic acid cycle of Taenia Solium oncosphere, immature and mature Cysticerci in vitro, and immature and mature Cysticerci in vivo to a certain degree, and enhanced fat decomposing, amino acid decomposing, xanthine decomposing metabolism, and on the other hand, the absorption of glucose was hindered; furthermore, both albendazole and oxfendazole inhibited the activities of the fumaric reductase (FR) complex noncompetently in vitro. Benzimidazole carbamate drugs could inhibit the activities of FR complex noncompetently and hinder the absorption of glucose.

  4. Carbamate pesticide induced toxic epidermal necrolysis

    Directory of Open Access Journals (Sweden)

    Rajendran N

    2001-09-01

    Full Text Available A 36-year-old male alleged to have consumed carbamate pesticide liquid (Baygon@ developed toxic epidermal necrolysis (TEN within twenty-four hours of intake. Though drugs have been commonly incriminated as offending agents for TEN, carbamate pesticide was found to be the causative agent in our case.

  5. Amino acid analysis of sub-picomolar amounts of proteins by precolumn fluorescence derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate.

    Science.gov (United States)

    Masuda, Akiko; Dohmae, Naoshi

    2011-12-01

    Amino acid analysis (AAA) method is the most accurate methodology for absolute quantification of proteins. The conventional postcolumn method employing ninhydrin labeling of amino acids, which is adopted in automatic amino acid analyzer, is limited by low sensitivity. Therefore, a highly sensitive AAA method is required to confirm the data obtained from mass spectrometry or N-terminal sequence analysis. To increase the sensitivity of AAA, an analytical method based on precolumn derivatization with fluorescent 6-aminoquinolyl-carbamyl (AQC) reagent and separation of the AQC-amino acid derivatives by ion-pair chromatography using a reversed-phase column is reported herein. The sensitive analysis of low abundance proteins requires strict prevention of environmental contamination. In this review, we provide a protocol for high sensitivity amino acid analysis and show that the amino acid composition of bovine serum albumin below 100 ng, i.e., 1.5 pmol, determined using the presented method, matched with the theoretical composition in with low standard deviations. These results suggest that the current AAA method is potentially applicable for highly sensitive analysis as a complement to mass spectrometry-based proteomics. PMID:22281536

  6. Organophosphorus and carbamate insecticide poisoning.

    Science.gov (United States)

    Vale, Allister; Lotti, Marcello

    2015-01-01

    Both organophosphorus (OP) and carbamate insecticides inhibit acetylcholinesterase (AChE), which results in accumulation of acetylcholine (ACh) at autonomic and some central synapses and at autonomic postganglionic and neuromuscular junctions. As a consequence, ACh binds to, and stimulates, muscarinic and nicotinic receptors, thereby producing characteristic features. With OP insecticides (but not carbamates), "aging" may also occur by partial dealkylation of the serine group at the active site of AChE; recovery of AChE activity requires synthesis of new enzyme in the liver. Relapse after apparent resolution of cholinergic symptoms has been reported with OP insecticides and is termed the intermediate syndrome. This involves the onset of muscle paralysis affecting particularly upper-limb muscles, neck flexors, and cranial nerves some 24-96 hours after OP exposure and is often associated with the development of respiratory failure. OP-induced delayed neuropathy results from phosphorylation and subsequent aging of at least 70% of neuropathy target esterase. Cramping muscle pain in the lower limbs, distal numbness, and paresthesiae are followed by progressive weakness, depression of deep tendon reflexes in the lower limbs and, in severe cases, in the upper limbs. The therapeutic combination of oxime, atropine, and diazepam is well established experimentally in the treatment of OP pesticide poisoning. However, there has been controversy as to whether oximes improve morbidity and mortality in human poisoning. The explanation may be that the solvents in many formulations are primarily responsible for the high morbidity and mortality; oximes would not be expected to reduce toxicity in these circumstances. even if given in appropriate dose. PMID:26563788

  7. Quantitative determination of amino acids in earthworm meal (Eisenia andrei) by a Surveyor HPLC system in conjunction with pre-column 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate derivatization

    OpenAIRE

    Ovalles-Dur??n, J.F.; Medina, A.; M??rquez, Elil; Rochette, Julie; Morillo, Marielba; Luna, Jos?? Rafael

    2014-01-01

    Aim: The objective of this study was to evaluate the integration of the AccQ???Tag derivatization system with the Finnigan Surveyor Plus HPLC system to determine the amino acids (aa) composition of earthworm meal protein post-hydrolysis. Materials and Methods: In lab cultivated earthworms (Eisenia andrei) were reduced to flour which was then hydrolyzed with 6M HCl at 110 ??C for 24 hours in a closed system. The hydrolysis product was neutralized and their aa were derivatized with 6-aminoqu...

  8. 76 FR 41135 - 2-Propenoic acid, 2-methyl-, phenylmethyl ester, polymer with 2-propenoic acid and sodium 2...

    Science.gov (United States)

    2011-07-13

    ... absorbing polymer with a number average molecular weight (MW) greater than or equal to 10,000 daltons...)- initiated minimum number average molecular weight > 1,000 Daltons; maximum number average molecular weight... Findings In the Federal Register of April 20, 2011 (76 FR 22069) (FRL-8869- 7), EPA issued a...

  9. BETA-GLUCURONYL CARBAMATE BASED PRO-MOIETIES DESIGNED FOR PRODRUGS IN ADEPT

    NARCIS (Netherlands)

    LEENDERS, RGG; GERRITS, KAA; RUIJTENBEEK, R; SCHEEREN, HW; Haisma, Hidde; BOVEN, E

    1995-01-01

    A number of pro-moieties 8a - e designed for prodrug preparation have been synthesized (chart 2). The pro-moieties, containing a glucuronyl carbamate group linked to a spacer possessing a terminal carboxylic acid group, have been synthesized from isocyanates 6 and anomerically unprotected glucuronic

  10. 19F nuclear magnetic resonance analysis of the carbamate reaction of alpha-fluoro-beta-alanine (FBAL), the major catabolite of fluoropyrimidines. Application to FBAL carbamate determination in body fluids of patients treated with 5'-deoxy-5-fluorouridine

    International Nuclear Information System (INIS)

    alpha-Fluoro-beta-alanine (FBAL), the major catabolite of the antineoplastic fluoropyrimidines, is an amino acid which is in equilibrium with its carbamate derivative in weakly alkaline aqueous solutions containing carbonate. In both water and control biological fluids (urine, plasma) spiked with FBAL (and sodium bicarbonate, in some cases), 19F NMR was used: (i) to determine the pH range over which FBAL carbamate is present (pH greater than or equal to 7), the maximum concentration formed occurring around pH 9, (ii) to show that the amino group of FBAL interacts very slowly with a non-protein plasma component to form a compound X, unstable in acid medium. The presumed structure of X is RCONHCH2CHFCOOH, with R different from an alkyl group but still unidentified. The behavior of FBAL in urine and plasma of rats treated with FBAL or 5'-deoxy-5-fluorouridine (5'-dFUrd), a prodrug of 5-fluorouracil, and from patients treated with 5'-dFUrd was investigated. FBAL carbamate was not present in acid medium and was therefore absent in acidic human urine. However, it was found in alkaline rat urine. FBAL carbamate was found in plasma along with the compound X. The 19F NMR spectra of FBAL and derivatives are complex since alpha-fluoro-beta-ureido-propionic acid, the precursor of FBAL in the catabolic pathway of antineoplastic fluoropyrimidines, produces a signal overlapping that of FBAL carbamate, and very close to that of compound X

  11. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted phenylimino carbamate... Specific Chemical Substances § 721.2025 Substituted phenylimino carbamate derivative. (a) Chemical... as a substituted phenylimino carbamate derivative (PMN P-91-487) is subject to reporting under...

  12. 21 CFR 520.434 - Chlorphenesin carbamate tablets.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chlorphenesin carbamate tablets. 520.434 Section... Chlorphenesin carbamate tablets. (a) Specifications. Each tablet contains 400 milligrams of chlorphenesin carbamate. (b) Sponsor. See No. 000009 in § 510.600(c) of this chapter. (c) Conditions of use in...

  13. Evaluation of carbamate insecticides as chemotherapeutic agents for cancer

    Directory of Open Access Journals (Sweden)

    Mohd. Amanullah

    2011-01-01

    Full Text Available Background: Cancer chemotherapy has already been in practice by the use of toxins and some of the specific poisonous compounds of cyanide derivatives. Carbamate insecticides inhibit cellular metabolism including energy, protein, and nucleic acid metabolism, thereby, causing cell regression and death. Aim: Preliminary evaluation of three carbamate insecticides, namely, baygon, carbaryl, and carbofuran as chemotherapeutic agents for cancer is undertaken in the present study. Materials and Methods: The toxicity of carbamates on squamous cell carcinoma was assessed in-vitro using dye binding tests. Cells were grown in microtitration ELISA plates, as adherent cultures, for six hours, and then exposed to the drugs for 2, 4, 8, and 12 hours, and finally stained with neutral red, to assess the viable cell number, and with methylene blue for the determination of protein in the monolayer. Optical density was read in an ELISA reader. Statistical Analysis: The data obtained during the experiment was subjected to statistical analysis by using the student ′t′ test. Results: The results indicated that the percentage of the viable cell number reduced with an increase in the time of exposure of the drugs. Exposure of the tumor cells to the drugs for 12 hours detached them completely from the wells, and hence, all the cells were washed out. Exposure of the drugs prior to the establishment of the culture in-vitro resulted in the non-formation of the monolayer in the wells. Conclusions: Among the three drugs studied, the survival percent was least with carbaryl treatment followed by baygon, and with carbofuran treatment it was almost near to control group.

  14. CUMULATIVE EFFECTS OF ORGANOPHOSPHORUS OR CARBAMATE PESTICIDES.

    Science.gov (United States)

    This book chapter strives to summarize the body of literature exploring the toxic interaction of organophosphorus and carbamate pesticides in mixtures. This review represents one of the only reviews of the subject that has been published within the last 20 years. Specifically, th...

  15. PPA-SiO2 Catalyzed Multi-component Synthesis of N-[α-(β-Hydroxy-α-naphthyl)(benzyl)]O-Alkyl Carbamate Derivatives

    Institute of Scientific and Technical Information of China (English)

    SHATERIAN,Hamid Reza; HOSSEINIAN,Asghar; GHASHANG,Majid

    2009-01-01

    Silica-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the multi-component condensation reaction of benzaldehydes,2-naphthol,and methyl/benzyl carbamate to afford the corresponding N-[α-(β-hydroxy-α-naphthyl)(benzyl)]O-alkyl carbamate derivatives in good to excellent yields.This new approach consistently has the advantage of short reaction time,high conversions,clean reaction profiles,and simple experimental and work-up procedures.

  16. Fatty Acid Amide Hydrolase (FAAH), Acetylcholinesterase (AChE), and Butyrylcholinesterase (BuChE): Networked Targets for the Development of Carbamates as Potential Anti-Alzheimer's Disease Agents.

    Science.gov (United States)

    Montanari, Serena; Scalvini, Laura; Bartolini, Manuela; Belluti, Federica; Gobbi, Silvia; Andrisano, Vincenza; Ligresti, Alessia; Di Marzo, Vincenzo; Rivara, Silvia; Mor, Marco; Bisi, Alessandra; Rampa, Angela

    2016-07-14

    The modulation of the endocannabinoid system is emerging as a viable avenue for the treatment of neurodegeneration, being involved in neuroprotective and anti-inflammatory processes. In particular, indirectly enhancing endocannabinoid signaling to therapeutic levels through FAAH inhibition might be beneficial for neurodegenerative disorders such as Alzheimer's disease, effectively preventing or slowing the progression of the disease. Hence, in the search for a more effective treatment for Alzheimer's disease, in this paper, the multitarget-directed ligand paradigm was applied to the design of carbamates able to simultaneously target the recently proposed endocannabinoid system and the classic cholinesterase system, and achieve effective dual FAAH/cholinesterase inhibitors. Among the two series of synthesized compounds, while some derivatives proved to be extremely potent on a single target, compounds 9 and 19 were identified as effective dual FAAH/ChE inhibitors, with well-balanced nanomolar activities. Thus, 9 and 19 might be considered as new promising candidates for Alzheimer's disease treatment. PMID:27309570

  17. Optimization of 1,2,5-Thiadiazole Carbamates as Potent and Selective ABHD6 Inhibitors #

    Science.gov (United States)

    Patel, Jayendra Z.; Nevalainen, Tapio J.; Savinainen, Juha R.; Adams, Yahaya; Laitinen, Tuomo; Runyon, Robert S.; Vaara, Miia; Ahenkorah, Stephen; Kaczor, Agnieszka A.; Navia-Paldanius, Dina; Gynther, Mikko; Aaltonen, Niina; Joharapurkar, Amit A.; Jain, Mukul R.; Haka, Abigail S.; Maxfield, Frederick R.; Laitinen, Jarmo T.; Parkkari, Teija

    2015-01-01

    At present, inhibitors of α/β-hydrolase domain 6 (ABHD6) are viewed as a promising approach to treat inflammation and metabolic disorders. This article describes the optimization of 1,2,5-thiadiazole carbamates as ABHD6 inhibitors. Altogether, 34 compounds were synthesized and their inhibitory activity was tested using lysates of HEK293 cells transiently expressing human ABHD6 (hABHD6). Among the compound series, 4-morpholino-1,2,5-thiadiazol-3-yl cyclooctyl(methyl)carbamate (JZP-430, 55) potently and irreversibly inhibited hABHD6 (IC50 44 nM) and showed good selectivity (∼230 fold) over fatty acid amide hydrolase (FAAH) and lysosomal acid lipase (LAL), the main off-targets of related compounds. Additionally, activity-based protein profiling (ABPP) indicated that compound 55 (JZP-430) displayed good selectivity among the serine hydrolases of mouse brain membrane proteome. PMID:25504894

  18. Synthesis and biological activity of beta-glucuronyl carbamate-based prodrugs of paclitaxel as potential candidates for ADEPT

    NARCIS (Netherlands)

    deBont, DBA; Leenders, RGG; Haisma, HJ; vanderMeulenMuileman, [No Value; Scheeren, HW

    1997-01-01

    The syntheses of prodrugs of paclitaxel, which can be used in ADEPT in order to target paclitaxel towards tumor cells, are described. The prodrugs 1 and 2a,b consist of a spacer molecule connected via a carbamate linkage to a beta-glucuronic acid. The spacer molecule is also connected via an ester l

  19. Sulfonamide and carbamate derivatives of 6-chloropurine: synthesis, characterization and antimicrobial activity evaluation

    Directory of Open Access Journals (Sweden)

    K. Venkata Narayana

    2016-07-01

    Full Text Available A series of new sulfonamide derivatives, 9-(substitutedbenzenesulfonyl-6-chloro-9H-purines 7(a-e and carbamate derivatives, 6-chloro-purine-9-carboxylic acid substituted alkyl/arylester 9(a-d, have been synthesized through an intermediate, sodium salt of 6-chloro-9(H-purine (6 which was prepared by the treatment of 6-chloro-9(H-purine (4 with sodium hydride. Structures of the newly synthesized compounds were elucidated by IR, NMR ( 1H and 13C, mass spectra and elemental analysis. Antimicrobial activity against three bacterial strains and three fungal strains at two different concentrations, 100 and 200 µg/mL including MIC values was investigated. Bio-screening data disclosed that most of the sulfonamide derivatives, 7a, 7c and 7d, and one carbamate derivative 9a showed promising antimicrobial activity having MIC values in the range of 18.0-25.0 µg/mL.

  20. VizieR Online Data Catalog: Rotational transitions of Methyl carbamate (Groner+, 2007)

    Science.gov (United States)

    Groner, P.; Winnewisser, M.; Medvedev, I. R.; de, F. C. Lucia; Herbst, E.; Sastry, K. V. L. N.

    2008-11-01

    The rotational-torsional spectrum of the syn conformer of methyl carbamate [CH3OC(:O)NH2], an isomer of the essential amino acid glycine [NH2CH2C(:O)OH], has been recorded at room temperature in the spectral region from 79 to 371GHz. Methyl carbamate possesses a methyl group internal rotor, which gives rise to A and E torsional substates, and associated splittings in the rotational spectrum. Almost 6000 new rotational transitions arising from the vibrational ground state have been assigned, about half of them belonging to the E torsional substate. The Fast Scan Submillimeter-wave Spectroscopic Technique (FASSST) spectrometer at the Ohio State University was used for the present measurements (2 data files).

  1. 76 FR 34200 - Land Disposal Restrictions: Revision of the Treatment Standards for Carbamate Wastes

    Science.gov (United States)

    2011-06-13

    ... Standards for Carbamate Wastes AGENCY: Environmental Protection Agency. ACTION: Proposed rule. SUMMARY: The...) treatment standards for hazardous wastes from the production of carbamates and carbamate commercial chemical... carbamate wastes must be treated to meet numeric concentration limits before they can be land...

  2. Synthesis and evaluation of 6-[11C]Methoxy-3-[2- [1-(phenylmethyl)-4-piperidinyl]ethyl]-1,2-benzisoxazole as an in vivo radioligand for acetylcholinesterase

    International Nuclear Information System (INIS)

    6-Methoxy-3-[2-[1-(phenylmethyl)-4-piperidinyl]ethyl]-1,2-benzisoxazole is a high affinity (Ki=8.2 nM) reversible inhibitor of acetylcholinesterase (AChE). The carbon-11 labeled form was prepared in high (>97%) radiochemical purity and with specific activities of 37 ± 20 GBq/μmol at end of synthesis, by the alkylation of the desmethyl precursor with [11C]methyl trifluoromethanesulfonate in N,N-dimethylformamide at room temperature. In vivo studies in mice demonstrated good blood brain permeability but essentially uniform regional brain distribution. Thus, despite in vitro and in vivo activity as an AChE inhibitor, 6-[11C]methoxy-3-[2-[1-(phenylmethyl)-4-piperidinyl]ethyl]-1, 2-benzisoxazole does not appear to be a good candidate for in vivo imaging studies of AChE in the mammalian brain

  3. Determination of Methyl Carbamate and Ethyl Carbamate in White Liquor by GC-MS%气相色谱-质谱联用测定白酒中的氨基甲酸甲酯和氨基甲酸乙酯

    Institute of Scientific and Technical Information of China (English)

    谭文渊; 袁东; 付大友; 李艳清; 王蓉

    2011-01-01

    建立一种测定白酒中的氨基甲酸甲酯和氨基甲酸乙酯的气相色谱-质谱联用(gas chromatography-massspectrometry,GC-MS)方法。GC-MS条件为:色谱柱HP-55%苯甲基硅氧烷(30.0m×0.25mm,0.25μm),进样1μL(分流比50:1),柱温170℃,质谱离子源温度230℃,四极杆温度150℃,全扫描方式的质量扫描范围m/z 30~500,溶剂延迟3min。样品采用氨基固相小柱萃取净化、氮吹浓缩定容。结果表明:氨基甲酸甲酯和氨基甲酸乙酯在2~30μg/mL范围内线性关系良好,相关系数为0.9923和0.9811,平均回收率为76.10%和75.43%,RSD为4.48%和4.00%。该方法可应用于白酒检测。%A gas chromatography-mass spectrometry(GC-MS) method has been established for the determination of methyl carbamate and ethyl carbamate in white liquor.The GC-MS conditions were column HP-55% phenylmethyl Siloxane(30.0 m × 0.25 mm,0.25μm) as the chromatography column,injection volume of 1μL(split ratio,50:1),column temperature of 170 ℃,ion source temperature of 230 ℃,quadrupole temperature of 150 ℃,mass scanning range(m/z) of 30-500 and solvent delay time of 3 min.The samples were purified by amino solid phase extraction column and then the eluent was evaporated to dryness using nitrogen blow.The results showed that the standard curves of methyl carbamate and ethyl carbamate revealed an excellent linear relationship in the concentration range of 2-30μg/mL with a correlation coefficient of respectively 0.9923 and 0.9811.The average recovery rates of this determination method for methyl carbamate and ethyl carbamate were 76.10% and 75.43% with a RSD of 4.48% and 4.00%,respectively.

  4. The Millimeter- and Submillimeter-Wave Spectrum of Methyl Carbamate [CH3OC(:O)NH2

    Science.gov (United States)

    Groner, Peter; Winnewisser, Manfred; Medvedev, Ivan R.; De Lucia, Frank C.; Herbst, Eric; Sastry, K. V. L. N.

    2007-03-01

    The rotational-torsional spectrum of the syn conformer of methyl carbamate [CH3OC(:O)NH2], an isomer of the essential amino acid glycine [NH2CH2C(:O)OH], has been recorded at room temperature in the spectral region from 79 to 371 GHz. Methyl carbamate possesses a methyl group internal rotor, which gives rise to A and E torsional substates, and associated splittings in the rotational spectrum. Almost 6000 new rotational transitions arising from the vibrational ground state have been assigned, about half of them belonging to the E torsional substate. Along with some earlier data, the newly measured lines were assigned and analyzed efficiently by the integration of two program packages: CAAARS, a suite for visual, interactive mouse-assisted line assignment of asymmetric rotor spectra; and ERHAM, a program that solves the effective Hamiltonian for molecules with up to two periodic large-amplitude internal motions. This Hamiltonian was used to fit 28 spectroscopic parameters for the methyl carbamate ground vibrational state to the observed line positions with a standard deviation of 0.081 MHz. With the determined spectroscopic constants and the available dipole moment components, we are able to predict the transition frequencies and intensities of many additional lines through 400 GHz. Methyl carbamate can now be searched for over a wide frequency range in appropriate interstellar sources such as hot molecular cores.

  5. Radiotracer Approaches to Carbamate Insecticide Toxicology

    International Nuclear Information System (INIS)

    Methylcarbamates constitute one of the major groups of insecticides. Many unresolved problems in their toxicology may be readily approached with radiotracer studies. Dimethylcarbamates have been prepared with carbonyl-C14-labelling and methylcarbamates withmethyl-, carbonyl-and ring-labelling utilizing carbon-14. The pharmacological action of these.compounds presumably results from acetylcholinesterase inhibition and may involve carbamylation. Reaction of carbonyl- or methyl-labelled carbamates with purified cholinesterase or other esterases would allow a critical examination of this carbamylation reaction and the ease of spontaneous and induced reactivation or decarbamylation. The physiological significance of cholinesterase inhibition might be examined by administering acetate-C14 and analysis for radiolabelled acetylcholine accumulation in nervous tissue, or by utilizing acetyl-C14-choline as the substrate for in vitro determination of the degree of cholinesterase inhibition in tissues of poisoned animals with minimal dilution of the inhibitors and enzymes during analysis. Some progress has been made with radiolabelled materials in investigating the metabolism of carbamate insecticides. Sevin (1-naphthyl methylcarbamate) has been most extensively studied along with its potential hydrolysis products. The assumption that the metabolism of Sevin involves an initial hydrolysis and then further decomposition of the fragments was not supported by carbon-14 studies. The major detoxification mechanism in mammals, and probably also in insects, results from initial oxidative attack on the carbamate by the microsomes in the presence of reduced nicotinamide-adenine dinucleotide phosphate. Sevin is rapidly metabolized in mammals, but the fate of certain of the fragments has not been resolved. Some of the metabolites appear in the milk of lactating animals. One step in the metabolism appears to be formation of the N-methylol derivative. Preliminary studies on the metabolism

  6. Mechanism of action of organophosphorus and carbamate insecticides.

    OpenAIRE

    Fukuto, T R

    1990-01-01

    Organophosphorus and carbamate insecticides are toxic to insects and mammals by virtue of their ability to inactivate the enzyme acetylcholinesterase. This review addresses the mechanism of inhibition of acetylcholinesterase by organophosphorus and carbamate esters, focusing on structural requirements necessary for anticholinesterase activity. The inhibition of acetylcholinesterase by these compounds is discussed in terms of reactivity and steric effects. The role of metabolic activation or d...

  7. Wildlife mortality attributed to organophosphorus and carbamate pesticides

    Science.gov (United States)

    Glaser, L.C.

    1995-01-01

    Organophosphorus (OP) and carbamate pesticides are used widely in agricultural and residential applications as insecticides, herbicides, fungicities. and rodenticides. This family of chemicals replaced the organochlorine pesticides banned for use in the United States in the 1970's. Unlike organochlorine pesticides, which are long-lived in the environment and cause biological damage when they accumulate in an organism's system over time. OP and carbamate pesticides are short-lived in the environment and fast-acting on their 'target pest.' Direct mortality of wildlife from organochlorine pesticides was uncommon (Hayes and Wayland 1975): however, mortality is the primary documented effect on wildlife from OP and carbamate pesticides (Grue et al. 1983). Organophosphorus and carbamate pesticide toxicity is not specific to a target 'pest,' and lethal effects are seen in nontarget organisms: birds appear to be the most sensitive class of animals affected by these pesticides. Organophosphorus and carbamate pesticides primainly affect the nervous system by inhibiting acetylcholinesterase (AChE) enzyme activity. This enzyme's main function in the nervous system is to break down the neurotransmitter acetylcholine. When AChE is altered by OP and carbamate pesticides, it cannot perform this breakdown function and acetylcholine accumulates. Acetylcholine accumulation increases nerve impulse transmission and leads to nerve exhaustion and. ultimately, failure of the nervous system. When the nervous system fails, muscles do not receive the electrical input they require to move. The respiratory muscles are the most critical muscle group affected, and respiratory paralysis is often the immediate cause of death.

  8. [Formation of ethyl carbamate in umeshu (plum liqueur)].

    Science.gov (United States)

    Suzuki, K; Kamimura, H; Ibe, A; Tabata, S; Yasuda, K; Nishijima, M

    2001-12-01

    Samples of umeshu, a Japanese plum liqueur made from unripe plums, shochu and crystal sugar, were stored under fluorescent light, in the dark and in the refrigerator. The amount of ethyl carbamate formed in umeshu exposed to light or room temperature was larger than that in the dark or at low temperature. The amount of ethyl carbamate formed in umeshu to which cyanide had been added was larger than that in the absence of added cyanide. Thus, the amount of ethyl carbamate formed in the umeshu was increased by not only light and higher temperature, but also cyanide. Samples of model alcoholic beverages were stored under various conditions using red, yellow and blue cellophanes. The amount of ethyl carbamate formed in the model alcoholic beverage with blue cellophane was larger than in the cases of red and yellow cellophanes. It was found that the amount of ethyl carbamate formed in the model alcoholic beverage was increased by light in the wavelength range of 375-475 nm. PMID:11875819

  9. 76 FR 34147 - Land Disposal Restrictions: Revision of the Treatment Standards for Carbamate Wastes

    Science.gov (United States)

    2011-06-13

    ... carbamates (61 FR 15583). These treatment standards were based on data for similar wastes for which EPA... CFR 268.48. EPA promulgated numeric treatment standards for these carbamate wastes in 1994 (59 FR... UHC carbamates. As a result, EPA promulgated an emergency rule in 1996 (61 FR 43924, August 26,...

  10. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Perfluoroalkyl aromatic carbamate... Significant New Uses for Specific Chemical Substances § 721.7200 Perfluoroalkyl aromatic carbamate modified...) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  11. Efficient Cellular Entry of (r-x-r)-Type Carbamate-Plasmid DNA Complexes and Its Implication for Noninvasive Topical DNA Delivery to Skin.

    Science.gov (United States)

    Vij, Manika; Natarajan, Poornemaa; Yadav, Amit K; Patil, Kiran M; Pandey, Tanuja; Gupta, Nidhi; Santhiya, Deenan; Kumar, Vaijayanti A; Fernandes, Moneesha; Ganguli, Munia

    2016-06-01

    Arginine-rich cell penetrating peptides are powerful tools for in vitro as well as in vivo delivery of a wide plethora of biomolecules. However, presence of consecutive arginine residues leads to enhanced amenability for proteolytic degradation as well as steric hindrances for membrane interactions which compromise its bioavailability. In order to overcome these limitations we previously reported a safe and stable octaarginine based oligomer, i.e., (r-x-r)4-carbamate, where the backbone amide linkages were replaced by carbamate linkages and 6-aminohexanoic acid based spacer moieties were incorporated for better flexibility, hydrophobicity, optimal spacing of guanidinium groups, and protection against proteolytic cleavage; resulting in improved transfection efficiency over its amide counterpart. In the present work we have investigated the mechanism behind this enhanced transfection efficiency and, based on our observations, demonstrate how the synergistic effect of rationalized oligomer designing, complex characteristics, and cell type contributes to overall effective intracellular delivery. Our results indicate that the (r-x-r)4-carbamate-plasmid DNA complexes primarily utilize lipid raft dependent pathway of cellular entry more than other pathways, and this possibly facilitates their increased entry in the lipid raft rich milieu of skin cells. We also emphasize the utility of oligomer (r-x-r)4-carbamate as an efficient carrier for topical delivery of nucleic acids in skin tissue. This carrier can be utilized for safe, efficient, and noninvasive delivery of therapeutically relevant macromolecular hydrophilic cargo like nucleic acids to skin. PMID:27175623

  12. Growth and characterization of organic single crystal benzyl carbamate

    Science.gov (United States)

    Bala Solanki, S. Siva; Perumal, Rajesh Narayana; Suthan, T.; Bhagavannarayana, G.

    2015-10-01

    Benzyl carbamate single crystal is grown by a solution and vertical Bridgman technique for the first time. The cell parameters and morphologies are assessed from single crystal X-ray diffraction analysis. High resolution X-ray diffraction analysis indicates the crystalline perfection of the grown benzyl carbamate crystal. Fourier Transforms Infrared spectroscopy study has been applied to arrive at the different functional groups. Thermo gravimetric analysis and differential scanning calorimetry are used to study its thermal behavior. The microhardness test is carried out and the load dependent hardness is measured.

  13. Preparation, crystal structure and luminescent properties of the (6,3) type network supramolecular lanthanide picrate complexes with 2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide

    International Nuclear Information System (INIS)

    Solid complexes of lanthanide picrates with a new podand-type ligand, 2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR and electronic spectroscopies. The crystal and molecular structures of the coordination polymer {[Eu2L3(Pic)6].(CHCl3)3.(H2O)0.5}n have been determined by single-crystal X-ray diffraction, and the structure displays a two-dimensional honeycomb-like framework in the ab plane, which can be regarded as a (6,3) topological network with europium atoms acting as 'three-connected' centers. Furthermore, the coordination layers are linked by the intermolecular hydrogen bonds to form a three-dimensional (3-D) netlike supermolecule. Under excitation, Eu complex exhibited characteristic emissions. The lowest triplet state energy level of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. - Graphical abstract: The (6,3) type network supramolecular luminescent lanthanide picrate complexes {Ln2L3(Pic)6}n (L=2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide) displaying a two-dimensional honeycomb-like framework have been designed and prepared.

  14. Purine twisted-intercalating nucleic acids: a new class of anti-gene molecules resistant to potassium-induced aggregation

    OpenAIRE

    Paramasivam, Manikandan; Cogoi, Susanna; Filichev, Vyacheslav V.; Bomholt, Niels; Pedersen, Erik B; Xodo, Luigi E.

    2008-01-01

    Sequence-specific targeting of genomic DNA by triplex-forming oligonucleotides (TFOs) is a promising strategy to modulate in vivo gene expression. Triplex formation involving G-rich oligonucleotides as third strand is, however, strongly inhibited by potassium-induced TFO self-association into G-quartet structures. We report here that G-rich TFOs with bulge insertions of (R)-1-O-[4-(1-pyrenylethynyl)-phenylmethyl] glycerol (called twisted intercalating nucleic acids, TINA) show a much lower te...

  15. A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

    Science.gov (United States)

    Two mathematical approaches were used to test the hypothesis ofdose-addition for a binary and a seven-chemical mixture ofN-methyl carbamates, toxicologically similar chemicals that inhibit cholinesterase (ChE). In the more novel approach, mixture data were not included in the ana...

  16. Induction of Tibial Dyschondroplasia by Carbamate and Thiocarbamate Pesticides

    Science.gov (United States)

    Tibial dyschondroplasia (TD) is a major poultry leg problem the natural etiology of which is unknown. Certain dithiocarbamate pesticides such as tetramethyl thiuram disulfide (thiram) have been shown to induce the disease in chickens. Since many different carbamate and thiocarbamate chemicals are ...

  17. Bioactive Paper Sensor Based on the Acetylcholinesterase for the Rapid Detection of Organophosphate and Carbamate Pesticides

    Directory of Open Access Journals (Sweden)

    Mohamed E. I. Badawy

    2014-01-01

    Full Text Available In many countries, people are becoming more concerned about pesticide residues which are present in or on food and feed products. For this reason, several methods have been developed to monitor the pesticide residue levels in food samples. In this study, a bioactive paper-based sensor was developed for detection of acetylcholinesterase (AChE inhibitors including organophosphate and carbamate pesticides. Based on the Ellman colorimetric assay, the assay strip is composed of a paper support (1×10 cm, onto which a biopolymer chitosan gel immobilized in crosslinking by glutaraldehyde with AChE and 5,5′-dithiobis(2-nitrobenzoic acid (DTNB and uses acetylthiocholine iodide (ATChI as an outside reagent. The assay protocol involves introducing the sample to sensing zone via dipping of a pesticide-containing solution. Following an incubation period, the paper is placed into ATChI solution to initiate enzyme catalyzed hydrolysis of the substrate, causing a yellow color change. The absence or decrease of the yellow color indicates the levels of the AChE inhibitors. The biosensor is able to detect organophosphate and carbamate pesticides with good detection limits (methomyl=6.16×10-4 mM and profenofos=0.27 mM and rapid response times (~5 min. The results show that the paper-based biosensor is rapid, sensitive, inexpensive, portable, disposable, and easy-to-use.

  18. Formation of Carbamate Anions by the Gas-phase Reaction of Anilide Ions with CO2

    Science.gov (United States)

    Liu, Chongming; Nishshanka, Upul; Attygalle, Athula B.

    2016-05-01

    The anilide anion ( m/z 92) generated directly from aniline, or indirectly as a fragmentation product of deprotonated acetanilide, captures CO2 readily to form the carbamate anion ( m/z 136) in the collision cell, when CO2 is used as the collision gas in a tandem-quadrupole mass spectrometer. The gas-phase affinity of the anilide ion to CO2 is significantly higher than that of the phenoxide anion ( m/z 93), which adds to CO2 only very sluggishly. Our results suggest that the efficacy of CO2 capture depends on the natural charge density on the nitrogen atom, and relative nucleophilicity of the anilide anion. Generally, conjugate bases generated from aniline derivatives with proton affinities (PA) less than 350 kcal/mol do not tend to add CO2 to form gaseous carbamate ions. For example, the anion generated from p-methoxyaniline (PA = 367 kcal/mol) reacts significantly faster than that obtained from p-nitroaniline (PA = 343 kcal/mol). Although deprotonated p-aminobenzoic acid adds very poorly because the negative charge is now located primarily on the carboxylate group, it reacts more efficiently with CO2 if the carboxyl group is esterified. Moreover, mixture of CO2 and He as the collision gas was found to afford more efficient adduct formation than CO2 alone, or as mixtures made with nitrogen or argon, because helium acts as an effective "cooling" gas and reduces the internal energy of reactant ions.

  19. Ionic carbamate photoacid/photobase generators for the advancement of dual-tone photolithography

    Science.gov (United States)

    Hallett-Tapley, Geniece L.; Wee, Tse-Luen; Eldo, Joby; Jackson, Edward A.; Blackwell, James M.; Scaiano, Juan C.

    2012-03-01

    Current work in lithographic patterning has been carried out using 193 nm excitation sources, limiting the pitch division to approximately λ/2 and, thus, the advancement of Moore's law. Recently, double patterning has emerged as a potential extension of 193 nm techniques as two lines can be patterned in one exposure. In this contribution, the double patterning features of single component carbamate photoacid/photobase generators (PAG/PBG) are examined. At lower exposure doses, sulfonic acid is generated, while at higher doses, a photochemical rearrangement is initiated to activate the PBG. Optimally, at intermediate doses, photoacid and photobase components can exist concurrently resulting in the desired dual tone lithographic features. The energy required to initiate dual tone behavior can be tailored through co-added amine quenchers and carbamate concentration. Using ellipsometry, the energy required for the resists to have the first sign of photoacid generation (film dissolution), E0, and at the energy required for photobase activation (En) were determined, as this value dictates the ability to achieve the desired pitch division.

  20. Synthesis of Novel Cellulose Carbamates Possessing Terminal Amino Groups and Their Bioactivity.

    Science.gov (United States)

    Ganske, Kristin; Wiegand, Cornelia; Hipler, Uta-Christina; Heinze, Thomas

    2016-03-01

    Cellulose phenyl carbonates are an excellent platform to synthesize a broad variety of soluble and functional cellulose carbamates. In this study, the synthesis of cellulose carbamates with terminal amino groups, namely ω-aminoethylcellulose- and ω-aminoethyl-p-aminobenzyl-cellulose carbamate, is discussed. The products are well soluble and their structures can be clearly described by NMR spectroscopy. The cellulose carbamates exhibit a bactericide and fungicide activity in vitro. The ω-aminoethylcellulose carbamate possesses a strong activity against Candida albicans and Staphylococcus aureus (IC50 of 0.02 mg mL(-1) and 0.05 mg mL(-1)). The antimicrobial activity and cytotoxicity can be improved by p-amino-benzylamine (ABA) as an additional substituent. The mixed cellulose carbamate exhibits a high biocompatibility (LC50 of 3.18 mg mL(-1)) and forms films on cotton and PES, which exhibit a strong activity against S. aureus and Klebsiella pneumoniae. PMID:26612063

  1. Synthesis and reactivity of cyclic-carbamate derivatives%环状氨基甲酸酯衍生物的合成及反应研究

    Institute of Scientific and Technical Information of China (English)

    王静; 郭爽; 王家喜

    2011-01-01

    Cyclic carbamate has been prepared by the reaction of ethanolamine with dimethyl carbonate as raw material and zinc acetate as catalyst. The cyclic carbamate reacted with methyl acrylate producing methyl 3- (2-oxo-oxazolidin-3-yl) propanoate, which reacted with n-butylamine and 1,6-hexanediamine to give mono and bis cyclic carbamate derivatives. The attack of amine to carbonyl of heterocyclic ring of carbamate produced the hydroxylethyl substituted urea, while the attack to carbon-oxygen bond generated carbamic acid, which further underwent dehydration forming cyclic urea and/or de-carbon dioxide forming polyamine. The products were characterized by NMR and FT-IR. The reaction mechanism is finally proposed.%以乙醇胺和碳酸二甲酯为原料,在醋酸锌的催化下合成环状氨基甲酸酯,与丙烯酸甲酯反应制备3-(2-噁唑烷酮)丙酸甲酯,在K2CO3催化下进一步与正丁胺、1,6-己二胺发生酰胺化反应,得到了单、双环状氨基甲酸酯衍生物.有机胺与环状氨基甲酸酯的羰基反应形成羟乙基取代脲,与烷氧基反应形成开环的胺基甲酸,该化合物进一步脱水形成环状脲,脱二氧化碳形成多胺化合物.用NMR和红外谱图对开环产物进行表征,并初步探讨了其反应历程.

  2. Biochemical and Histopathological Changes in The Rat Following Exposure to a Carbamate Pesticide

    International Nuclear Information System (INIS)

    Oxamyl is a carbamate pesticide with an oral LD50 of 5.4 mg/kg for male rats. To evaluate the subacute toxicity of the compound, two groups of male rats were dosed with 0.9 and 2.5 mg/kg/day of the pesticide, for 16 days. Toxicological evaluation included clinical chemistry and histopathological changes at the end of the study. The compound significantly altered serum alkaline phosphatase, uric acid, cholesterol, creatinine, blood urea nitrogen (BUN), serum glutamic pyruvic transaminase (SGPT and testosterone. Liver, Kidney and testicular histology revealed mild degenerative changes in the liver with the lower dose and significant degenerative changes with increased lymphocytic infiltrate with the higher dose and mild degenerative changes of the kidney with the higher dose only. Examination of the testis revealed no pathological changes at both dose levels

  3. Carbamate Pesticide-Induced Apoptosis in Human T Lymphocytes

    Directory of Open Access Journals (Sweden)

    Qing Li

    2015-04-01

    Full Text Available We previously found that carbamate pesticides induced significant apoptosis in human natural killer cells. To investigate whether carbamate pesticides also induce apoptosis in human T lymphocytes, in the present study Jurkat human T cells were treated in vitro with thiram, maneb, carbaryl or ziram. Apoptosis was determined by FITC-Annexin-V/PI staining. To explore the mechanism of apoptosis, intracellular levels of active caspase 3 and mitochondrial cytochrome-c release were determined by flow cytometry. We found that thiram, ziram, maneb and carbaryl also induced apoptosis in a time- and dose-dependent manner in the human T cells. However, the strength of the apoptosis-inducing effect differed among the pesticides, with the: thiram > ziram > maneb > carbaryl. Moreover, thiram significantly increased the intracellular level of active caspase 3 and caspase inhibitors significantly inhibited apoptosis. Thiram also significantly caused mitochondrial cytochrome-c release. These findings indicate that carbamate pesticides can induce apoptosis in human T cells, and the apoptosis is mediated by the activation of caspases and the release of mitochondrial cytochrome-c.

  4. DOSE-RESPONSE MODELING FOR THE ASSESSMENT OF CUMULATIVE RISK DUE TO EXPOSURE TO N-METHYL CARBAMATE PESTICIDES

    Science.gov (United States)

    The US EPAs N-Methyl Carbamate Cumulative Risk Assessment (NMCRA) assesses the effect on acetylcholine esterase (AChE) activity of exposure to 10 N-methyl carbamate (NMC) pesticides through dietary, drinking water, and residential exposures.

  5. Survey of ethyl carbamate in fermented foods sold in the United Kingdom in 2004.

    Science.gov (United States)

    Hasnip, Sarah; Crews, Colin; Potter, Nicholas; Christy, Julie; Chan, Danny; Bondu, Thomas; Matthews, Wendy; Walters, Barry; Patel, Krishna

    2007-04-01

    Results are presented of a survey of fermented foods and beverages sold in the United Kingdom for levels of ethyl carbamate (urethane) carried out to expand the range of food types sold in the United Kingdom for which data regarding ethyl carbamate are available. Samples were analyzed by in-house validated methods, which included measurement uncertainty estimates. The samples comprised 75 fermented liquids (beers, wines, fortified wines, spirits, liqueurs, soy sauces, and vinegars) and 25 fermented solid foods (cheeses, yogurts, soybean products, sauerkraut, yeast extract, olives, and Christmas pudding). Ethyl carbamate was not detected in the beers or the cider. Wines contained between 11 and 24 microg/kg and sake between 81 and 164 microg/kg. Fortified wines contained ethyl carbamate at levels between 14 and 60 microg/kg. Only two of five liqueurs contained ethyl carbamate. Most soy sauces and vinegars did not contain ethyl carbamate. No ethyl carbamate was detected in cheeses, yogurts, olives, or soybean-based products. Single samples of sauerkraut, yeast extract, and Christmas pudding contained low levels (29, 41, and 20 microg/kg ethyl carbamate, respectively). PMID:17328558

  6. Mild and Site-Selective Allylation of Enol Carbamates with Allylic Carbonates under Rhodium Catalysis.

    Science.gov (United States)

    Sharma, Satyasheel; Han, Sang Hoon; Oh, Yongguk; Mishra, Neeraj Kumar; Han, Sangil; Kwak, Jong Hwan; Lee, Seok-Yong; Jung, Young Hoon; Kim, In Su

    2016-03-18

    The rhodium(III)-catalyzed mild and site-selective C-H allylation of enol carbamates with 4-vinyl-1,3-dioxolan-2-one and allylic carbonates affords allylic alcohols and terminal allylated products, respectively. The assistance of the carbamoyl directing group provides a straightforward preparation of biologically and synthetically important allylated enol carbamates. PMID:26906724

  7. Palladium-Catalyzed Ortho-Arylation of Carbamate-Protected Estrogens.

    Science.gov (United States)

    Bedford, Robin B; Brenner, Peter B; Durrant, Steven J; Gallagher, Timothy; Méndez-Gálvez, Carolina; Montgomery, Michelle

    2016-05-01

    The palladium-catalyzed ortho-arylation of diethyl carbamate-protected estrone and estriol with aryl iodides gives the 2-arylated analogues. Subsequent removal of the carbamate directing group furnishes 2-arylated estrone, estradiol, or estriol depending on the method used. PMID:27057762

  8. Facile one-pot synthesis of unsymmetrical ureas, carbamates, and thiocarbamates from Cbz-protected amines.

    Science.gov (United States)

    Kim, Hee-Kwon; Lee, Anna

    2016-07-26

    A novel one-pot synthesis of unsymmetrical ureas, carbamates and thiocarbamates from Cbz-protected amines has been developed. In the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, isocyanates are generated in situ, which facilitate rapid reaction with amines, alcohols, and thiols to afford the corresponding ureas, carbamates and thiocarbamates in high yields. PMID:27406041

  9. 40 CFR 180.212 - S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues. 180.212 Section 180.212 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Tolerances § 180.212 S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues. (a) General....

  10. NMDA antagonists exert distinct effects in experimental organophosphate or carbamate poisoning in mice

    International Nuclear Information System (INIS)

    Organophosphate (OP) and carbamate acetylcholinesterase (AChE) inhibitors produce seizures and lethality in mammals. Anticonvulsant and neuroprotective properties of N-methyl-D-aspartate (NMDA) antagonists encourage the investigation of their effects in AChE inhibitor-induced poisonings. In the present study, the effects of dizocilpine (MK-801, 1 mg/kg) or 3-((RS)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP, 10 mg/kg), alone or combined with muscarinic antagonist atropine (1.8 mg/kg), on convulsant and lethal properties of an OP pesticide dichlorvos or a carbamate drug physostigmine, were studied in mice. Both dichlorvos and physostigmine induced dose-dependent seizure activity and lethality. Atropine did not prevent the occurrence of convulsions but decreased the lethal effects of both dichlorvos and physostigmine. MK-801 or CPP blocked or attenuated, respectively, dichlorvos-induced convulsions. Contrariwise, NMDA antagonists had no effect in physostigmine-induced seizures or lethality produced by dichlorvos or physostigmine. Concurrent pretreatment with atropine and either MK-801 or CPP blocked or alleviated seizures produced by dichlorvos, but not by physostigmine. Both MK-801 and CPP co-administered with atropine enhanced its antilethal effects in both dichlorvos and physostigmine poisoning. In both saline- and AChE inhibitor-treated mice, no interaction of the investigated antidotes with brain cholinesterase was found. The data indicate that both muscarinic ACh and NMDA receptor-mediated mechanisms contribute to the acute toxicity of AChE inhibitors, and NMDA receptors seem critical to OP-induced seizures

  11. A Novel Non-phosgene Process for the Synthesis of Methyl N-Phenyl Carbamate from Methanol and Phenylurea:Effect of Solvent and Catalyst

    Institute of Scientific and Technical Information of China (English)

    WANG,Xin-Kui(王心葵); YAN,Shi-Run(闫世润); CAO,Yong(曹勇); FAN,Kang-Nian(范康年); HE,He-Yong(贺鹤勇); KANG,Mao-Qing(亢茂青); PENG,Shao-Yi(彭少逸)

    2004-01-01

    A novel environmentally benign process for the synthesis of methyl N-phenyl carbamate (MPC) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to MPC increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n-octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to MPC while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases studied.

  12. Synthesis and decreasing Aβ content evaluation of arctigenin-4-yl carbamate derivatives.

    Science.gov (United States)

    Xu, Xingyu; Li, Cong; Lei, Min; Zhu, Zhiyuan; Yan, Jianming; Shen, Xu; Hu, Lihong

    2016-07-01

    A series of arctigenin-4-yl carbamate derivatives were synthesized and evaluated for potency in reducing β-amyloid (Aβ) content in HEK293-APPswe cells. Most of the arctigenin-4-yl aralkyl or aryl carbamate derivatives showed improved potency in reducing Aβ content. Among the synthesized compounds, arctigenin-4-yl (3-chlorophenyl)carbamate (20) exhibited the strongest potency with 78.7% Aβ content reduction at 20μM. Furthermore, the effect of arctigenin-4-yl (4-chlorophenyl)carbamate (19) and arctigenin-4-yl (3-chlorophenyl)carbamate (20) on lowing Aβ content was better than arctigenin under the concentrations of 1, 10 and 20μM. PMID:27212069

  13. Ultra-Trace Determination of Methyl Carbamate and Ethyl Carbamate in Local Wines by GC-FID Following Pre concentration with C18-SPE

    Directory of Open Access Journals (Sweden)

    Supawadee Sarawan

    2014-09-01

    Full Text Available An analytical method is described for ultra-trace determination of methyl carbamate and ethyl carbamate in locally produced fruit wines. The quantitative analysis involves with dichloromethane extraction followed by 30-fold preconcentration using C18 SPE prior to measurement by capillary GC-FID. Under the optimized conditions, a good linearity of their calibration curves was obtained in the range of 0.1-50.0 mg/L with r2 > 0.994. LOD and LOQ were 3.3-16.7 µg/L and 11.1-55.6 µg/L, respectively. The averaged recovery of these carbamates was ranged of 82.2-95.2% with RSD < 8.76%. The procedure was applied to determine both carbamate residues in various local wine samples. It was found that the concentration range of methyl carbamate (6.9-24.1 µg/L was rather fluctuated and higher than that of ethyl carbamate (2.6-4.3 µg/L, suggesting that is a certain residual background contamination naturally occurring in the wine fermentation.

  14. Piezoelectric Biosensors for Organophosphate and Carbamate Pesticides: A Review

    Directory of Open Access Journals (Sweden)

    Giovanna Marrazza

    2014-09-01

    Full Text Available Due to the great amount of pesticides currently being used, there is an increased interest for developing biosensors for their detection. Among all the physical transducers, piezoelectric systems have emerged as the most attractive due to their simplicity, low instrumentation costs, possibility for real-time and label-free detection and generally high sensitivity. This paper presents an overview of biosensors based on the quartz crystal microbalance, which have been reported in the literature for organophosphate and carbamate pesticide analysis.

  15. Inhibition Mechanism of Cholinesterases by Carbamate: A Theoretical Study

    Institute of Scientific and Technical Information of China (English)

    YAO Yuan; LI Ze-sheng

    2008-01-01

    The density functional theory at the B3LYP/6-311G(d,p) level was applied to exploring the inhibition mechanism of cholinesterases by carbamate.The results indicate that the inhibition reactions with or without the catalytic effect of the catalytic triad in cholinesterases underwent a two-step addition-elimination mechanism,which is in good agreement with the proposed mechanism.The solvent has a strong effect on the inhibition reactions and the reaction with the catalytic triad in the solvent phase is close to the real reaction under biological condition.

  16. New Water-Soluble Carbamate Ester Derivatives of Resveratrol

    Directory of Open Access Journals (Sweden)

    Andrea Mattarei

    2014-10-01

    Full Text Available Low bioavailability severely hinders exploitation of the biomedical potential of resveratrol. Extensive phase-II metabolism and poor water solubility contribute to lowering the concentrations of resveratrol in the bloodstream after oral administration. Prodrugs may provide a solution—protection of the phenolic functions hinders conjugative metabolism and can be exploited to modulate the physicochemical properties of the compound. We report here the synthesis and characterization of carbamate ester derivatives of resveratrol bearing on each nitrogen atom a methyl group and either a methoxy-poly(ethylene glycol-350 (mPEG-350 or a butyl-glucosyl promoiety conferring high water solubility. Ex vivo absorption studies revealed that the butyl-glucosyl conjugate, unlike the mPEG-350 one, is able to permeate the intestinal wall. In vivo pharmacokinetics confirmed absorption after oral administration and showed that no hydrolysis of the carbamate groups takes place. Thus, sugar groups can be attached to resveratrol to obtain soluble derivatives maintaining to some degree the ability to permeate biomembranes, perhaps by facilitated or active transport.

  17. tert-Butyl N-benzyl-N-[4-(4-fluorobenzoylmethyl-2-pyridyl]carbamate

    Directory of Open Access Journals (Sweden)

    Pierre Koch

    2008-11-01

    Full Text Available In the crystal structure of the title compound, C25H25FN2O3, the pyridine ring makes dihedral angles of 75.1 (3, 39.4 (3 and 74.6 (3° with the phenyl ring, the carbamate plane and the 4-fluorophenyl ring, respectively. The phenyl ring makes dihedral angles of 77.2 (3 and 23.6 (3° with the carbamate plane and the 4-fluorophenyl ring, respectively. The 4-fluorophenyl ring is perpendicular to the carbamate plane, the dihedral angle between them being 89.5 (3°.

  18. Cumulative risk assessment of the intake of organophosphorus and carbamate pesticides in the Danish diet

    DEFF Research Database (Denmark)

    Jensen, A. F.; Petersen, Annette; Granby, Kit

    2003-01-01

    in the Danish nation-wide food consumption survey in 1995. The pesticide data are based on the Danish pesticide residue-monitoring programme from 1996-2001. The amount of 35 organophosphorus pesticides and carbamates were included in the cumulative risk assessment. Processing factors, such as reduction......The aim of the study is to evaluate the potential cumulative effects of organophosphorus and carbamate pesticides that act through a common mechanism of toxicity, and to assess the long- and short-term risks for the Danish population. The intake estimates are based on dietary intake data collected...... of pesticide levels by rinsing and peeling, were applied in the exposure assessment. The "Toxicity Equivalence Factor" (TEF) approach was used to normalise the toxicity of the different organophosphorus and carbamate pesticides. Cumulative chronic exposure of organophosphorus and carbamates pesticides via...

  19. The thermal desorption of CO2 from amine carbamate solutions for the 13C isotope enrichment

    Science.gov (United States)

    Dronca, S.; Varodi, C.; Gligan, M.; Stoia, V.; Baldea, A.; Hodor, I.

    2012-02-01

    The CO2 desorption from amine carbamate in non-aqueous solvents is of major importance for isotopic enrichment of 13C. A series of experiments were carried out in order to set up the conditions for the CO2 desorption. For this purpose, a laboratory- scale plant for 13C isotope separation by chemical exchange between CO2 and amine carbamate was designed and used. The decomposition of the carbamate solution was mostly produced in the desorber and completed in the boiler. Two different-length desorbers were used, at different temperatures and liquid flow rates of the amine-non-aqueous solvent solutions. The residual CO2 was determined by using volumetric and gaschromatographic methods. These results can be used for enrichment of 13C by chemical exchange between CO2 and amine carbamate in nonaqueous solvents.

  20. Carbamates toxicity in farmers and its assesment through biochemical parameters

    International Nuclear Information System (INIS)

    Prevalent environmental toxicity of various chemical group of pesticides and their effects leading towards increasing morbidity and mortality in the farmers is of great concerned. In this situation the biochemical biomarkers are regarded as meaningful tools for monitoring toxic end points. This work was aimed to assess the toxic impacts of carbamates through some biochemical parameters and useful validity of these biomarkers was also observed. Present results reveal inhibition of cholinesterase activity by 46% whereas bilirubin, urea and creatinine levels in serum were increased and sugar values was decreased at highly significant level (p<0.001). Urine urobilinogen concentration found raised significantly at high level (p<0.001) while protein, urea creatinine and sugar values in urine of the farmers seen non-significant. This study concluded that the selected biochemical parameters can be used as biomarkers to assess the significant toxic effects in the exposed populations. (author)

  1. Potent Urea and Carbamate Inhibitors of Soluble Epoxide Hydrolases

    Science.gov (United States)

    Morisseau, Christophe; Goodrow, Marvin H.; Dowdy, Deanna; Zheng, Jiang; Greene, Jessica F.; Sanborn, James R.; Hammock, Bruce D.

    1999-08-01

    The soluble epoxide hydrolase (sEH) plays a significant role in the biosynthesis of inflammation mediators as well as xenobiotic transformations. Herein, we report the discovery of substituted ureas and carbamates as potent inhibitors of sEH. Some of these selective, competitive tightbinding inhibitors with nanomolar Ki values interacted stoichiometrically with the homogenous recombinant murine and human sEHs. These inhibitors enhance cytotoxicity of trans-stilbene oxide, which is active as the epoxide, but reduce cytotoxicity of leukotoxin, which is activated by epoxide hydrolase to its toxic diol. They also reduce toxicity of leukotoxin in vivo in mice and prevent symptoms suggestive of acute respiratory distress syndrome. These potent inhibitors may be valuable tools for testing hypotheses of involvement of diol and epoxide lipids in chemical mediation in vitro or in vivo systems.

  2. Ethyl carbamate levels in selected fermented foods and beverages.

    Science.gov (United States)

    Canas, B J; Havery, D C; Robinson, L R; Sullivan, M P; Joe, F L; Diachenko, G W

    1989-01-01

    Ethyl carbamate (EC), also known as urethane, is an animal carcinogen and a by-product of fermentation. Because EC has been found in distilled spirits and wines, a variety of fermented foods and beverages were analyzed to assess its occurrence in other products. Previously described methods using a gas chromatograph-thermal energy analyzer with a nitrogen converter were modified for each matrix and gave recoveries of greater than 80%, with a limit of detection in the 1-2 micrograms/kg (ppb) range. A total of 152 test samples were analyzed; EC levels ranged from none found to 3 ppb in 15 cheeses, 6 teas, 12 yogurts, and 8 ciders; from none found to 13 ppb in 30 breads and 69 malt beverages; and from none found to 84 ppb in 12 soy sauces. Gas chromatography/mass spectrometry/mass spectrometry was used to confirm EC identity and to quantitate EC in selected food extracts. PMID:2592308

  3. Novel aryl carbamate derivatives of metronidazole as potential antiamoebic agents.

    Science.gov (United States)

    Hayat, Faisal; Wahedi, Hussain Mustatab; Park, Seonghyeok; Tariq, Saba; Azam, Amir; Shin, Dongyun

    2016-01-01

    A series of novel aryl carbamate derivatives of metronidazole (MNZ) were designed, synthesized, and screened for antiamoebic activity. As compared to MNZ, most of the derivatives exhibited moderate to excellent activity against the HM1:IMSS strain of Entamoeba histolytica. Compounds 7, 14, 16, 19, and 21 exhibited the most promising antiamoebic activity with IC50 values of 0.24, 0.08, 0.26, 0.26, and 0.15 μM, respectively, compared to that of MNZ (1.78 μM). Moreover, from the toxicological studies of these compounds on human melanocytes, the melan-a cell line revealed that the potent compounds are nontoxic at concentrations ranging from 2.5 to 50 μM. PMID:26597858

  4. Semi disposable reactor biosensors for detecting carbamate pesticides in water.

    Science.gov (United States)

    Suwansa-ard, Siriwan; Kanatharana, Proespichaya; Asawatreratanakul, Punnee; Limsakul, Chusak; Wongkittisuksa, Booncharoen; Thavarungkul, Panote

    2005-09-15

    Two flow-injection biosensor systems using semi disposable enzyme reactor have been developed to determine carbamate pesticides in water samples. Acetylcholinesterase was immobilized on silica gel by covalent binding. pH and conductivity electrodes were used to detect the ionic change of the sample solution due to hydrolysis of acetylcholine. Carbamate pesticides inhibited acetylcholinesterase and the decrease in the enzyme activity was used to determine these pesticides. Parameters influencing the performance of the systems were optimized to be used in the inhibition procedure. Carbofuran and carbaryl were used to test these systems. Detection limits for the potentiometric and conductimetric systems were both at 10% inhibition corresponding to 0.02 and 0.3 ppm of carbofuran and carbaryl, respectively. Both systems also provided the same linear ranges, 0.02-8.0 ppm for carbofuran, and 0.3-10 ppm for carbaryl. The analysis of pesticides was done a few times before the reactor was disposed. Percentages of inhibition obtained from different reactors were reproducible, therefore, no recalibration was necessary when changing the reactor. The biosensors were used to analyze carbaryl in water samples from six wells in a vegetable growing area. Both systems could detect the presence of carbaryl in the samples and provided good recoveries of the added carbaryl, i.e., 80-106% for the potentiometric system and 75-105% for the conductimetric system. The presence of carbaryl in water samples analyzed by the biosensors was confirmed by gas chromatography-mass spectrometric system. These biosensors do not require any sample preconcentration and are suitable for detecting pesticides in real water samples. PMID:16076434

  5. Selective effects of carbamate pesticides on rat neuronal nicotinic acetylcholine receptors and rat brain acetylcholinesterase

    International Nuclear Information System (INIS)

    Effects of commonly used carbamate pesticides on rat neuronal nicotinic acetylcholine receptors expressed in Xenopus laevis oocytes have been investigated using the two-electrode voltage clamp technique. The potencies of these effects have been compared to the potencies of the carbamates to inhibit rat brain acetylcholinesterase. The potency order of six carbamates to inhibit α4β4 nicotinic receptors is fenoxycarb > EPTC > carbaryl, bendiocarb > propoxur > aldicarb with IC50 values ranging from 3 μM for fenoxycarb to 165 μM for propoxur and >1 mM for aldicarb. Conversely, the potency order of these carbamates to inhibit rat brain acetylcholinesterase is bendiocarb > propoxur, aldicarb > carbaryl >> EPTC, fenoxycarb with IC50 values ranging from 1 μM for bendiocarb to 17 μM for carbaryl and >>1 mM for EPTC and fenoxycarb. The α4β2, α3β4, and α3β2 nicotinic acetylcholine receptors are inhibited by fenoxycarb, EPTC, and carbaryl with potency orders similar to that for α4β4 receptors. Comparing the potencies of inhibition of the distinct subtypes of nicotinic acetylcholine receptors shows that the α3β2 receptor is less sensitive to inhibition by fenoxycarb and EPTC. The potency of inhibition depends on the carbamate as well as on a combination of α and β subunit properties. It is concluded that carbamate pesticides affect different subtypes of neuronal nicotinic receptors independently of acetylcholinesterase inhibition. This implicates that neuronal nicotinic receptors are additional targets for some carbamate pesticides and that these receptors may contribute to carbamate pesticide toxicology, especially after long-term exposure

  6. Carbamate Toxicity and Protective effect of vit. A and vit. E on some biochemicalaspects of male albino rats

    Directory of Open Access Journals (Sweden)

    Samir, A.M. Zaahkouk* ; Eman, G.E. Helal

    2000-12-01

    Full Text Available The effect of daily oral administration of carbamate (1/10 L.D50 on rats for 30 successive days were studied. The male rats were divided into five groups (control, control + oil, carbamate, carbamate + vit. A and carbamate + vit. E. Each group (except control and control + oil was daily administrated carbamate (0.012 mg/kg B.wt.. Two groups of carbamate ­ intoxicated animals provided with vit. A (700 mg/kg.B.wt or vit. E (10 mg/kg.B.wt. Poisoning symptoms were recorded, e.g. unbalanse, diarrhea, have poor health and posterior limbs rigidity. Haematological parameters showed a significant decrease in red blood corpuscles (R.B.Cs, white blood corpuscles (W.B.Cs count, Haemoglobin concentration and haematocrit value in groups treated with carbamate, and an improvement in these values was observed in groups treated with the anti-oxidants (vit. A and vit. E. Total lipids cholesterol, total proteins, albumin, glucose, LDH, AST, ALT, adrenaline and noradrenaline were measured in serum. Total proteins, total lipids, of tissues (liver, heart, muscle and kidney were investigated. The present study declare that, carbamate induced a significant elevetion in serum LDH, glucose. total lipids,cholesterol, AST, ALT, adrenaline and noradrenaline. On the other hand, causes a significant reduction in total proteins and albumin. The total lipids and total proteins of the tissue were recorded highly significant decrease in the group treated with carbamate only. From another point of view, antioxidant ameliorated the effect of carbamate on tissues. So, it is clear that administration of vit. E or vit. A. reduced the effect of carbamate on biochemical alteration to various extent. The antioxidant property of vitamin A and vitamin E seem to be responsible for the observed protection against carbamate intoxication.

  7. Cyanate as an Active Precursor of Ethyl Carbamate Formation in Sugar Cane Spirit.

    Science.gov (United States)

    Galinaro, Carlos A; Ohe, Thiago H K; da Silva, Augusto C H; da Silva, Sebastião C; Franco, Douglas W

    2015-08-26

    The thermodynamic and kinetic aspects of ethyl carbamate (EC) formation through the reaction between cyanate and ethanol were investigated. The rate constant values for cyanate ion decay and EC formation are (8.0 ± 0.4) × 10(-5) and (8.9 ± 0.4) × 10(-5) s(-1), respectively, at 25 °C in 48% aqueous ethanolic solution at pH 4.5. Under the investigated experimental conditions, the rate constants are independent of the ethanol and cyanate concentrations but increase as the temperature increases (ΔH1(⧧) = 19.4 ± 1 kcal/mol, ΔS1(⧧) = −12.1 ± 1 cal/K, and ΔG1(⧧) = 23.0 ± 1 kcal/mol) and decrease as the solution pH increases. According to molecular modeling (DFT) that was performed to analyze the reaction mechanism, the isocyanic acid (HNCO) is the active EC precursor. The calculated ΔG1(⧧), ΔH1(⧧), and ΔS1(⧧) values are in very good agreement with the experimental ones. PMID:26248556

  8. Reduced production of ethyl carbamate for wine fermentation by deleting CAR1 in Saccharomyces cerevisiae.

    Science.gov (United States)

    Guo, Xue-Wu; Li, Yuan-Zi; Guo, Jian; Wang, Qing; Huang, Shi-Yong; Chen, Ye-Fu; Du, Li-Ping; Xiao, Dong-Guang

    2016-05-01

    Ethyl carbamate (EC), a pluripotent carcinogen, is mainly formed by a spontaneous chemical reaction of ethanol with urea in wine. The arginine, one of the major amino acids in grape musts, is metabolized by arginase (encoded by CAR1) to ornithine and urea. To reduce the production of urea and EC, an arginase-deficient recombinant strain YZ22 (Δcarl/Δcarl) was constructed from a diploid wine yeast, WY1, by successive deletion of two CAR1 alleles to block the pathway of urea production. The RT-qPCR results indicated that the YZ22 almost did not express CAR1 gene and the specific arginase activity of strain YZ22 was 12.64 times lower than that of parent strain WY1. The fermentation results showed that the content of urea and EC in wine decreased by 77.89 and 73.78 %, respectively. Furthermore, EC was forming in a much lower speed with the lower urea during wine storage. Moreover, the two CAR1 allele deletion strain YZ22 was substantially equivalent to parental strain in terms of growth and fermentation characteristics. Our research also suggested that EC in wine originates mainly from urea that is produced by the arginine. PMID:26831650

  9. Influence of Solvent on Reaction Path to Synthesis of Methyl N-Phenyl Carbamate from Aniline, CO2 and Methanol

    Institute of Scientific and Technical Information of China (English)

    安华良; 张丽丽; 苑保国; 赵新强; 王延吉

    2014-01-01

    Methyl N-phenyl carbamate (MPC), an important organic chemical, can be synthesized from aniline, CO2 and methanol. Catalyst Cu-Fe/ZrO2-SiO2 was first prepared and its catalytic performance for MPC synthesis was evaluated. Then the influence of solvent on the reaction path of MPC synthesis was investigated. It is found that the reaction intermediate is different with acetonitrile or methanol as a solvent. With acetonitrile as a solvent, the synthesis of MPC follows the reaction path with diphenyl urea as the intermediate, while with methanol as a solvent the reaction occurs via the reaction path with dimethyl carbonate as the intermediate. The catalytic mecha-nism of cooperative catalysis comprising metal sites, Lewis acid sites and Lewis base sites is proposed according to different reaction intermediates.

  10. (1S,3S,4S)-tert-Butyl N-[1-benzyl-3-hydr­oxy-5-phenyl-4-(picolinamido)pent­yl]carbamate

    OpenAIRE

    Jian-Feng Zheng; Su-Yu Huang; Jian-Nan Guo; Yu Zhang; Li-Ren Jin

    2008-01-01

    The title compound, C29H35N3O4, was obtained by the reaction of (2S,4S,5S)-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentyl)carbamate and picolinic acid using oxalyl chloride as a chlorinating reagent to activate the carboxyl group. In the crystal structure there are two molecules in the asymmetric unit, which are aligned edge-to-face. In one molecule, the pyridyl ring forms a dihedral angle of 22.0 (1)° with the phenyl ring of the terminal benzyl group and 14.3 (1)...

  11. An electrochemical study for corrosion inhibition of iron by some organic phosphonium chloride derivatives in acid media

    International Nuclear Information System (INIS)

    The inhibiting action of (chloromethyl) triphenyl phosphonium chloride (CTP), tetraphenyl phosphonum chloride (TP), triphenyl phosphine oxide (TPO), triphenyl (phenylmethyl) phosphonium chloride (TPM) and triphenyl phosphine (TPP) on the corrosion of iron in 1 M HCl solution was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Experimental results revealed that CTP, TP, TPO, and TPM act as inhibitors for iron in acid environments, while TPP is an accelerator. These compounds are mixed-type inhibitors and the inhibition efficiency increased with increasing concentrations. Equivalent circuits of the investigated systems are suggested

  12. Study on the Interaction between Humic Substances in Soil and Carbamate Pesticides Using Fluorescence Quenching Titration Method%荧光猝灭滴定法研究土壤腐殖质与氨基甲酸酯类农药相互作用

    Institute of Scientific and Technical Information of China (English)

    施国兰; 郑博福; 白英臣; 吴丰昌; 吴代赦

    2012-01-01

    为研究氨基甲酸酯类农药在溶解有机质参与下的迁移转化过程,利用荧光猝灭滴定法研究了土壤HS(腐殖质)与氨基甲酸酯类农药的相互作用.结果表明,呋喃丹和西维因的荧光都能不同程度地被FA(富里酸)和HA(腐殖酸)猝灭,主要猝灭机理为静电结合猝灭.采用静态猝灭模型计算出氨基甲酸酯类农药与HS的K(结合常数),lg K由大到小为呋喃丹-HA(4.96)>西维因-HA(4.93)>呋喃丹-FA(4.72)>西维因-FA(4.68).HA与氨基甲酸酯类农药的lgK明显大于FA与氨基甲酸酯类农药,表明HS与氨基甲酸酯类农药间的作用力有疏水作用.进一步研究表明,氢键作用对HS与氨基甲酯类农药结合有一定的影响.%To reveal the mechanisms of transport and conversion of carbamate pesticides in the presence of dissolved organic matters, the fluorescence quenching titration method was applied to investigate the interactions between carbamate pesticides and humic substances in soil. The results showed that the intrinsic fluorescence of carbofuran and carbaryl was quenched by the fulvic and humic acids to varying degrees. Static quenching was the primary mechanism during this process. The binding constants (K) of carbamate pesticides and humic substances were estimated using the fluorescence static quenching model. The order of lg K were: those of carbofuran and humic acid (4. 96) > those of carbaryl and humic acid (4. 93) > those of carbofuran and fulvic acid (4. 72) > those of carbaryl and fulvic acid (4. 68). The values of lg K of carbamate pesticides and humic acids were clearly higher than those of carbamate pesticides and fulvic acids. This result indicated that the hydrophobic force is one of the main interactions between carbamate pesticides and humic substances, and further proved that hydrogen bonding could slightly affect the bonding of carbamate pesticides and humic substances.

  13. Lignin is linked to ethyl-carbamate formation in ume (Prunus mume) liqueur.

    Science.gov (United States)

    Hashiguchi, Tomokazu; Izu, Hanae; Sudo, Shigetoshi

    2012-01-01

    Ethyl carbamate concentrations in oak barrel-aged ume (Prunus mume) liqueurs were measured, and possible explanations for elevated levels were examined. The average concentration was 0.30 mg/L, significantly higher than in ume liqueurs not aged in oak (0.08 mg/L). Oak powder extracts were prepared from both untoasted and toasted oak powder by extraction with aqueous ethanol, and these were used to make ume liqueurs. Relative to a no-oak control, the ethyl carbamate concentrations were 3.8 and 11 times higher in the ume liqueur made with the untoasted and toasted oak powder extracts respectively. The extracts were loaded onto a C18 column, washed with water, and eluted with methanol. The (13)C-NMR spectra for the main constituents of the methanol elution fractions were consistent with those for lignin or fragments thereof. The methanol fractions were added to ume liqueur which was stored for 3 months. Relative to a control, the ethyl carbamate concentrations in the 3-month old liqueurs were found to be 1.2 and 4.6 higher for the untoasted oak-powder and the toasted oak-powder respectively. Ethyl carbamate was formed when lignin was added to a 40% aqueous ethanol solution that contained potassium cyanide. These observations suggest that lignin or fragments thereof promote the formation of ethyl carbamate. PMID:22232267

  14. Copper(II) catalysis in cyanide conversion into ethyl carbamate in spirits and relevant reactions.

    Science.gov (United States)

    Aresta, M; Boscolo, M; Franco, D W

    2001-06-01

    The role of copper(II) species in the oxidation of inorganic cyanide to cyanate and in the conversion of cyanate or urea into ethyl carbamate was investigated. The oxidation process has been shown to be independent from the dissolved oxygen. Elemental analysis and infrared spectroscopy have shown the formation of a mixed copper carbonate/hydroxide in the process of oxidation of cyanide to cyanate in water/ethanol. The complexation to Cu(II) of cyanate formed upon cyanide oxidation makes the former more susceptible to nucleophilic attack from ethanol, with conversion into ethyl carbamate. Comparatively, urea has a minor role with respect to cyanide in the formation of ethyl carbamate. Therefore, the urea present in some samples of Brazilian sugar cane spirit (cachaça) has been shown to have almost no influence on the ethyl carbamate content of cachaças, which comes essentially from cyanide. Fe(II,III) affords results similar to those found with Cu(II). Some suggestions are presented to avoid ethyl carbamate formation in spirits during distillation. PMID:11409971

  15. Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea under mild conditions

    Institute of Scientific and Technical Information of China (English)

    Jun Jie Gao; Hui Quan Li; Yi Zhang

    2007-01-01

    Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.

  16. Benzimidazole Carbamate Residues in Milk: Detection by SPR Biosensor; using a Modified QuEChERS Method for Extraction

    Science.gov (United States)

    A surface plasmon resonance (SPR) biosensor screening assay was developed and validated to detect 11 benzimidazole carbamate (BZT) veterinary drug residues in milk. The polyclonal antibody used was raised in sheep against a methyl 5 (6)-[(carboxypentyl)-thio]-2-benzimidazole carbamate protein conjug...

  17. Assessment of Acute Oral and Dermal Toxicity of 2 Ethyl-Carbamates with Activity against Rhipicephalus microplus in Rats

    Directory of Open Access Journals (Sweden)

    María Guadalupe Prado-Ochoa

    2014-01-01

    Full Text Available The acute oral and dermal toxicity of two new ethyl-carbamates (ethyl-4-bromophenyl-carbamate and ethyl-4-chlorophenyl-carbamate with ixodicide activity was determined in rats. The oral LD50 of each carbamate was 300 to 2000 mg/kg, and the dermal LD50 of each carbamate was >5000 mg/kg. Clinically, the surviving rats that had received oral doses of each carbamate showed decreased weight gain (P<0.05 and had slight nervous system manifestations. These clinical signs were evident from the 300 mg/kg dose and were reversible, whereas the 2000 mg/kg dose caused severe damage and either caused their death or was motive for euthanasia. At necropsy, these rats had dilated stomachs and cecums with diffuse congestion, as well as moderate congestion of the liver. Histologically, the liver showed slight degenerative lesions, binucleated hepatocytes, focal coagulative necrosis, and congestion areas; the severity of the lesions increased with dosage. Furthermore, an slight increase in gamma-glutamyltransferase, lactate dehydrogenase, and creatinine was observed in the plasma. The dermal application of the maximum dose (5000 mg/kg of each carbamate did not cause clinical manifestations or liver and skin alterations. This finding demonstrates that the carbamates under study have a low oral hazard and low acute dermal toxicity.

  18. (BOSC) DOSE-RESPONSE MODELING FOR THE ASSESSMENT OF CUMULATIVE RISK DUE TO EXPOSURE TO N-METHYL CARBAMATE PRESTICIDES

    Science.gov (United States)

    THE US EPA'S N-METHYL CARBAMATE CUMULATIVE RISK ASSESSMENT (NMCRA) ASSESSES THE EFFECT ON ACETYLCHOLINE ESTERASE (AChE) ACTIVITY OF EXPOSURE TO 10 N-METHLY CARBAMATE (NMC)PESTICIDES THROUGH DIETARY, DRINKING WATER, AND RESIDENTIAL EXPOSURES. THESE DATA THUS INFORM, BUT DO NOT COM...

  19. Gas chromatographic-mass spectrometric determination of ethyl carbamate in alcoholic beverages.

    Science.gov (United States)

    Lau, B P; Weber, D; Page, B D

    1987-07-31

    A sensitive and specific method based on gas chromatography-mass spectrometry for the quantitative determination of ethyl carbamate in table wines, fortified wines (such as ports and sherries), distilled spirits, brandies and liqueurs has been developed. Three characteristic ions from ethyl carbamate [m/z 89 (molecular ion), 74 and 62] were monitored in the selected-ion monitoring (SIM) mode. The lowest detection limit (based on the response on the m/z 62 ion) was estimated to be 0.5 ng/g (ppb). Additional confirmation techniques, including high-resolution SIM, and methane or isobutane chemical ionization are described. PMID:3654867

  20. The carcinogenic potential of ethyl carbamate (urethane): risk assessment at human dietary exposure levels

    OpenAIRE

    Schlatter, J; Werner K Lutz

    2012-01-01

    Ethyl carbamate is found in fermented foods: bread contains 3-15 ng/g, stone-fruit brandies 200-20,000 ngfg, and about one-third of table-wine samples analysed contained more than 10 ng/g. In animals, ethyl carbamate is degraded to C02, H20 and NH3, with intermediate formation ofethanol. This degradation has been shown tobe inhibited (postponed) in the mouse by ethanol concentrations in the blood of about 0.15% and higher. A quantitatively minor pathway involves a two-step oxidation of the et...

  1. Application of brain cholinesterase reactivation to differentiate between organophosphorus and carbamate pesticide exposure in wild birds

    Science.gov (United States)

    Smith, M.R.; Thomas, N.J.; Hulse, C.

    1995-01-01

    Brain cholinesterase activity was measured to evaluate pesticide exposure in wild birds. Thermal reactivation of brain cholinesterase was used to differentiate between carbamate and organophosphorus pesticide exposure. Brain cholinesterase activity was compared with gas chromatography and mass spectrometry of stomach contents. Pesticides were identified and confirmed in 86 of 102 incidents of mortality from 29 states within the USA from 1986 through 1991. Thermal reactivation of cholinesterase activity was used to correctly predict carbamates in 22 incidents and organophosphates in 59 incidents. Agreement (P < 0.001) between predictions based on cholinesterase activities and GC/MS results was significant.

  2. Investigations of primary and secondary amine carbamate stability by 1H NMR spectroscopy for post combustion capture of carbon dioxide

    International Nuclear Information System (INIS)

    Highlights: ► Carbamate stability constants of series of amines have been measured at (288 to 318) K. ► Standard molar enthalpies and entropies have been determined by van’t Hoff analyses. ► A ΔHmo-ΔSmo plot for carbamate formation gives a linear relationship. ► This relationship provides a guide for the selection of amines for PCC applications. ► Stereochemical effects and intramolecular H-bonding affect carbamate formation. - Abstract: Carbamate formation is one of the major chemical reactions that can occur in solution in the capture of CO2 by amine-based solvents, and carbamate formation makes a significant enthalpy contribution to the absorption-desorption of CO2 that occurs in the absorber/stripper columns of the PCC process. Consequently, the formation of carbamates of selected series of primary and secondary amines over the temperature range (288 to 318) K has been investigated by equilibrium 1H NMR studies, and the stability constants (K9) for the equilibrium: RNH2+HCO3-⇄K9RNHCOO-+H2O are reported. van’t Hoff analyses have resulted in standard molar enthalpies, ΔHmo, and entropies, ΔSmo, of carbamate formation. A ΔHmo-ΔSmo plot generates a linear correlation for carbamate formation (providing a mean standard molar free energy, ΔGmo, for carbamate formation of about −7 kJ · mol−1), and this relationship helps provide a guide to the selection of an amine(s) solvent for CO2 capture, in terms of enthalpy considerations. A linear ΔHmo-ΔSmo plot also occurs for carbamate protonation. The formation of the carbamates has been correlated with systematic changes in composition and structure, and steric effects have been identified by comparing molecular geometries obtained using density functional B3LYP/6-311++G(d,p) calculations. Trends in steric effects have been identified in the series of compounds monoethanolamine (MEA), 1-amino-2-propanol, 2-amino-1-propanol (AP) and 2-amino-2-methyl-1-propanol (AMP). In the case of 2

  3. Investigation of ethyl carbamate levels in some fermented foods and alcoholic beverages.

    Science.gov (United States)

    Dennis, M J; Howarth, N; Key, P E; Pointer, M; Massey, R C

    1989-01-01

    An analytical procedure has been developed for the determination of trace amounts of ethyl carbamate in fermented foodstuffs and alcoholic beverages. Concentrations were generally below the 1-5 micrograms/kg detection limit in bread, cheese, yoghurt, beer, gin and vodka. Higher concentrations were found in the other alcoholic beverages examined, which included whisky, fruit brandy, liqueur, wine, sherry and port. PMID:2721787

  4. Computational study of structural properties of lithium cation complexes with carbamate-modified disiloxanes.

    Science.gov (United States)

    Jeschke, Steffen; Wiemhöfer, Hans-Dieter; Mück-Lichtenfeld, Christian

    2014-07-21

    Lithium cation solvation structures [Li(S)(n=1-4)](+) with ligands of cyclic or noncyclic carbamate-modified disiloxanes are optimized at B3LYP level of theory and compared to their corresponding simplified carbamates and to the organic carbonates ethylene carbonate (EC) and dimethyl carbonate (DMC). The electrostatic potentials (ESP) of these investigated carbonyl-containing solvents are mapped on the electron density surface. The maximum ESP is located at the C=O-oxygen, whereas the disiloxane functionality represents an unpolar residue. Natural Bond Orbitals (NBO) analysis reveals strong n(N) →π(C[double bond, length as m-dash]O) donor-acceptor interactions in carbamates which outrun dipolar properties. As a result, higher total binding energies (ΔE(B)) for solvation of Li(+) in carbamates (-148 kcal mol(-1)) are found than for carbonates (-137 kcal mol(-1)). Furthermore, the disiloxane moiety with its Si-O bond is stabilized by n(O) →σ*(Si-C) hyperconjugation that provides additional electron density to a nearby SiCH3 methyl group thus supporting an additional SiCH2-H...Li(+) coordination. The formation of all investigated solvation structures is exothermic. Owing to steric hindrance of noncyclic carbonyl-containing ligands and the bulky disiloxane functionality, the solvation structure [Li(S)3](+) is the preferred structure according to Gibbs free energy ΔG(B) results. PMID:24914737

  5. Detection of benzimidazole carbamates and amino metabolites in liver by surface plasmon resonance-biosensor

    Science.gov (United States)

    Two surface plasmon resonance (SPR) biosensor screening assays were developed and validated to detect 11 benzimidazole carbamate (BZT) and four amino-benzimidazole veterinary drug residues in liver tissue. The assays used polyclonal antibodies, raised in sheep, to detect BZTs and amino-benzimidazole...

  6. Photochemical decomposition of carbamate pesticides in natural waters of northern Greece

    International Nuclear Information System (INIS)

    The photochemical decomposition of the carbamate pesticides carbofuran, carbaryl and thiram was examined in natural waters of northern Greece under the influence of solar and UV (λ > 290 nm) radiation. Different major photoproducts were detected by GC/MS. The result of continuous irradiation was almost total degradation of the pesticides examined

  7. Light Induced C-C Coupling of 2-Chlorobenzazoles with Carbamates, Alcohols, and Ethers.

    Science.gov (United States)

    Lipp, Alexander; Lahm, Günther; Opatz, Till

    2016-06-01

    A light induced, transition-metal-free C-C coupling reaction of 2-chlorobenzazoles with aliphatic carbamates, alcohols, and ethers is presented. Inexpensive reagents, namely sodium acetate, benzophenone, water, and acetonitrile, are employed in a simple reaction protocol using a cheap and widely available 25 W energy saving UV-A lamp at ambient temperature. PMID:27128627

  8. Fenugreek hydrogel–agarose composite entrapped gold nanoparticles for acetylcholinesterase based biosensor for carbamates detection

    International Nuclear Information System (INIS)

    A biosensor was fabricated to detect pesticides in food samples. Acetylcholinesterase was immobilized in a novel fenugreek hydrogel–agarose matrix with gold nanoparticles. Transparent thin films with superior mechanical strength and stability were obtained with 2% fenugreek hydrogel and 2% agarose. Immobilization of acetylcholinesterase on the membrane resulted in high enzyme retention efficiency (92%) and a significantly prolonged shelf life of the enzyme (half-life, 55 days). Transmission electron microscopy revealed that, gold nanoparticles (10–20 nm in diameter) were uniformly dispersed in the fenugreek hydrogel–agarose–acetylcholinesterase membrane. This immobilized enzyme-gold nanoparticle dip-strip system detected various carbamates, including carbofuran, oxamyl, methomyl, and carbaryl, with limits of detection of 2, 21, 113, and 236 nM (S/N = 3), respectively. Furthermore, the fabricated biosensor exhibited good testing capabilities when used to detect carbamates added to various fruit and vegetable samples. - Highlights: • Acetylcholinesterase (AChE) dip-strip biosensor fabricated to detect carbamates. • AChE entrapped in fenugreek hydrogel–agarose matrix with gold nanoparticles (GNPs). • High enzyme retention efficiency (92%) and shelf life (half-life, 55 days). • Detection limits of carbofuran, oxamyl and methomyl: 2, 21 and 113 nM. • The biosensor had good testing capabilities to detect carbamates in food samples

  9. Fenugreek hydrogel–agarose composite entrapped gold nanoparticles for acetylcholinesterase based biosensor for carbamates detection

    Energy Technology Data Exchange (ETDEWEB)

    Kestwal, Rakesh Mohan; Bagal-Kestwal, Dipali; Chiang, Been-Huang, E-mail: bhchiang@ntu.edu.tw

    2015-07-30

    A biosensor was fabricated to detect pesticides in food samples. Acetylcholinesterase was immobilized in a novel fenugreek hydrogel–agarose matrix with gold nanoparticles. Transparent thin films with superior mechanical strength and stability were obtained with 2% fenugreek hydrogel and 2% agarose. Immobilization of acetylcholinesterase on the membrane resulted in high enzyme retention efficiency (92%) and a significantly prolonged shelf life of the enzyme (half-life, 55 days). Transmission electron microscopy revealed that, gold nanoparticles (10–20 nm in diameter) were uniformly dispersed in the fenugreek hydrogel–agarose–acetylcholinesterase membrane. This immobilized enzyme-gold nanoparticle dip-strip system detected various carbamates, including carbofuran, oxamyl, methomyl, and carbaryl, with limits of detection of 2, 21, 113, and 236 nM (S/N = 3), respectively. Furthermore, the fabricated biosensor exhibited good testing capabilities when used to detect carbamates added to various fruit and vegetable samples. - Highlights: • Acetylcholinesterase (AChE) dip-strip biosensor fabricated to detect carbamates. • AChE entrapped in fenugreek hydrogel–agarose matrix with gold nanoparticles (GNPs). • High enzyme retention efficiency (92%) and shelf life (half-life, 55 days). • Detection limits of carbofuran, oxamyl and methomyl: 2, 21 and 113 nM. • The biosensor had good testing capabilities to detect carbamates in food samples.

  10. Acetylcholinesterase inhibition as an indicator of organophosphate and carbamate poisoning in Kenyan agricultural workers.

    NARCIS (Netherlands)

    Ohayo-Mitoko, G.J.A.; Heederik, D.; Kromhout, H.; Omondi, B.E.O.; Boleij, J.S.M.

    1997-01-01

    Acetylcholinesterase inhibition was determined for 666 Kenyan agricultural workers; 390 (58.6%) mainly pesticide applicators exposed to organophosphate and carbamate pesticides and 276 (41.4%) unexposed controls from four rural agricultural areas during 1993 and 1994. Baseline levels were depressed

  11. Evaluation of ethyl N-(2-phenethyl) carbamate analogues as biofilm inhibitors of methicillin resistant Staphylococcus aureus.

    Science.gov (United States)

    Stephens, Matthew D; Yodsanit, Nisakorn; Melander, Christian

    2016-07-12

    A small molecule library consisting of 45 compounds was synthesized based on the bacterial metabolite ethyl N-(2-phenethyl) carbamate. Screening of the compounds revealed a potent analogue capabale of inhibiting several strains of Methicillin Resistant S. aureus biofilms with low to moderate micromolar IC50 values. PMID:27341658

  12. Carbamate Stabilities of Sterically Hindered Amines from Quantum Chemical Methods: Relevance ofr CO2 Capture

    NARCIS (Netherlands)

    Gangarapu, S.; Marcelis, A.T.M.; Zuilhof, H.

    2013-01-01

    The influence of electronic and steric effects on the stabilities of carbamates formed from the reaction of CO2 with a wide range of alkanolamines was investigated by quantum chemical methods. For the calculations, B3LYP, M11-L, MP2, and spin-component-scaled MP2 (SCS-MP2) methods were used, coupled

  13. The dissociation chemistry of ionized methyl carbamate and its isomers revisited: Theory and experiment in concert

    NARCIS (Netherlands)

    P.C. Burgers (Peter); G.A. McGibbon (Graham); K.J. Jobst (Karl)

    2012-01-01

    textabstractEarly combined computational and experimental studies by J.K. Terlouw and colleagues propose that low-energy methyl carbamate ions, NH 2COOCH 3 •+ (MC-1), rearrange into distonic ions NH 2C(OH)OCH 2 •+ and hydrogen-bridged radical cations [NH 2C=O-H-OCH 2] •+ (MC-5) en route to the obser

  14. Diethyl [(4-nitrobenzamido(phenylmethyl]phosphonate

    Directory of Open Access Journals (Sweden)

    Jing-Wei Chen

    2014-05-01

    Full Text Available In the title compound, C18H21N2O6P, the dihedral angle between the benzene and phenyl rings is 85.1 (2°. In the crystal, molecules are linked via pairs of N—H...O(=P hydrogen bonds, forming inversion dimers with graph-set notation R22(10. One of the ethyl groups is disordered over two sets of sites, with occupancies 0.746 (11 and 0.254 (11.

  15. Novel Cholinesterase Inhibitors Based on O-Aromatic N,N-Disubstituted Carbamates and Thiocarbamates.

    Science.gov (United States)

    Krátký, Martin; Štěpánková, Šárka; Vorčáková, Katarína; Švarcová, Markéta; Vinšová, Jarmila

    2016-01-01

    Based on the presence of carbamoyl moiety, twenty salicylanilide N,N-disubstituted (thio)carbamates were investigated using Ellman's method for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). O-Aromatic (thio)carbamates exhibited weak to moderate inhibition of both cholinesterases with IC50 values within the range of 1.60 to 311.0 µM. IC50 values for BChE were mostly lower than those obtained for AChE; four derivatives showed distinct selectivity for BChE. All of the (thio)carbamates produced a stronger inhibition of AChE than rivastigmine, and five of them inhibited BChE more effectively than both established drugs rivastigmine and galantamine. In general, 5-chloro-2-hydroxy-N-[4-(trifluoromethyl)-phenyl]benzamide, 2-hydroxy-N-phenylbenzamide as well as N-methyl-N-phenyl carbamate derivatives led to the more potent inhibition. O-{4-Chloro-2-[(4-chlorophenyl)carbamoyl]phenyl} dimethylcarbamothioate was identified as the most effective AChE inhibitor (IC50 = 38.98 µM), while 2-(phenylcarbamoyl)phenyl diphenylcarbamate produced the lowest IC50 value for BChE (1.60 µM). Results from molecular docking studies suggest that carbamate compounds, especially N,N-diphenyl substituted representatives with considerable portion of aromatic moieties may work as non-covalent inhibitors displaying many interactions at peripheral anionic sites of both enzymes. Mild cytotoxicity for HepG2 cells and consequent satisfactory calculated selectivity indexes qualify several derivatives for further optimization. PMID:26875979

  16. The concentration of ethyl carbamate in commercial ume (Prunus mume) liqueur products and a method of reducing it.

    Science.gov (United States)

    Hashiguchi, Tomokazu; Horii, Sachie; Izu, Hanae; Sudo, Shigetoshi

    2010-01-01

    The ethyl carbamate concentration of commercial ume liqueur products was studied, and a method of reducing it was examined from the viewpoint of antioxidation. The average ethyl carbamate concentration across 38 ume liqueur products was 0.12 mg/l (0.02-0.33 mg/l). When potassium metabisulfite was added to a concentration of 0-1,000 ppm during production, the generation of ethyl carbamate was reduced in a concentration-dependent manner, but when the amount of potassium metabisulfite added was below the maximum level allowed under the Japanese Food Sanitation Act, the reduction was only 27%. When ume liqueurs were produced under deoxygenated conditions created using an oxygen absorber, the ethyl carbamate concentration was reduced by up to 47% as compared with the control group, probably due mainly to a reduction in free hydrogen cyanide. When ume liqueur was produced in an oxygen atmosphere, the ethyl carbamate concentration increased by up to 50% as compared with the control group. Thus, oxygen may be involved in the generation of ethyl carbamate in ume liqueur production. PMID:20944415

  17. Highly conductive polymer electrolyte membranes modified with polyethylene glycol-bis-carbamate

    Science.gov (United States)

    Fu, Guopeng; Dempsey, Janel; Kyu, Thein

    By virtue of its non-flammability and chemical stability, polyethylene glycol (PEG) networks have shown potential application in all solid-state polymer electrolyte membranes (PEM). However, room temperature ionic conductivity of these PEG based PEMs is inherently low. Plasticization of these PEMs is needed to improve the ionic conductivity. It was demonstrated by this group that small-molecule plasticizers such as succinonitrile, ethylene carbonate, or urea-carbamate can boost ionic conductivity of solid-state polymer electrolyte membranes. Polyethylene glycol bis-carbamate (PEGBC) was synthesized via condensation reaction of polyethylene glycol diamine and ethylene carbonate. The PEGBC modified PEM has shown higher ionic conductivity relative to the unmodified PEM. Moreover, PEGBC modified PEM has a better thermal stability relative to ethylene carbonate based liquid electrolyte with enhanced ionic conductivity. Supported by NSF-DMR 1161070, 1502543 and REU 1359321.

  18. New HPLC method to determine ethyl carbamate in alcoholic beverages using fluorescence detection

    OpenAIRE

    Herbert, P; Santos, L.; Bastos, M.; Barros, P.; Alves, A.

    2002-01-01

    A new methodology to the quantification of ethyl carbamate (EC) has been developed. This method allows the analysis by HPLC of ethyl carbarnate in samples of wine, fortified wine, and wine brandy, by a precolumn derivatization with 9-xanthydrol, and fluorescence detection. This does not require previous sample extraction or concentration. The method presents an average recovery of 96% among samples studied, a detection limit of 4.2 mug/L, and an average intermediate precision of 6.3%. The com...

  19. Bioactive Paper Sensor Based on the Acetylcholinesterase for the Rapid Detection of Organophosphate and Carbamate Pesticides

    OpenAIRE

    2014-01-01

    In many countries, people are becoming more concerned about pesticide residues which are present in or on food and feed products. For this reason, several methods have been developed to monitor the pesticide residue levels in food samples. In this study, a bioactive paper-based sensor was developed for detection of acetylcholinesterase (AChE) inhibitors including organophosphate and carbamate pesticides. Based on the Ellman colorimetric assay, the assay strip is composed of a paper support (1...

  20. Management of exogenous intoxication by carbamates and organophosphates at an emergency unit

    Directory of Open Access Journals (Sweden)

    Sydney Correia Leão

    2015-10-01

    Full Text Available Summary Objectives: to evaluate and indicate the procedure to be followed in the health unit, both for diagnosis and the treatment of acute exogenous intoxications by carbamates or organophosphates. Methods: a descriptive study based on retrospective analysis of the clinical history of patients diagnosed with intoxication by carbamates or organophosphates admitted at the emergency unit of the Hospital de Urgências de Sergipe Governador João Alves (HUSE between January and December of 2012. Some criteria were evaluated, such as: intoxicating agent; patient's age and gender; place of event, cause, circumstances and severity of the intoxication; as well as signs and symptoms of the muscarinic, nicotinic and neurological effects. Results: seventy patients (average age: 25±19.97 formed the study's population. It was observed that 77.14% of them suffered carbamate intoxication. However, organophosphate intoxications were more severe, with 68.75% of patients presenting moderate to severe forms. Suicide attempt was the leading cause of poisoning, with 62 cases (88.57% of total. Atropine administration was an effective therapeutic approach for treating signs and symptoms, which included sialorrhea (p=0.0006, nausea (p=0. 0029 and emesis (p lt0.0001. The use of activated charcoal was shown effective, both in combating the signs and symptoms presented by both patient groups (p <0.0001. Conclusion: it is concluded that the use of atropine and activated charcoal is highly effective to treat the signs and symptoms developed by patients presenting acute exogenous intoxication by carbamates or organophosphates.

  1. A Homogenous Luminescence Assay Reveals Novel Inhibitors for Giardia Lamblia Carbamate Kinase

    OpenAIRE

    Chen, Catherine Z.; Southall, Noel; Galkin, Andrey; Lim, Kap; Juan J. Marugan; Kulakova, Liudmila; Shinn, Paul; van Leer, Danielle; Zheng, Wei; Herzberg, Osnat

    2012-01-01

    The human pathogen Giardia lamblia is an anaerobic protozoan parasite that causes giardiasis, one of the most common diarrheal diseases worldwide. Although several drugs are available for the treatment of giardisis, resistance to these drugs has been reported and is likely to increase. The Giardia carbamate kinase (glCK) plays an essential role in Giardia metabolism and has no homologs in humans, making it an attractive candidate for anti-Giardia drug development. We have developed a luminesc...

  2. Deconvolution Method for Determination of the Nitrogen Content in Cellulose Carbamates

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Cellulose carbamates (CC) were synthesized with microcrystalline cellulose as raw materials. The Fourier transform infrared spectra of CC with different nitrogen content were recorded. The accurate results of the nitrogen content for CC can be obtained by using the deconvolution method when the nitrogen content is less than 3.5%. The relationship between the nitrogen content and the absorption intensity ratio of the corresponding separated absorption peaks in FTIR spectra has been expressed by an equation precisely.

  3. Determination of Ethyl Carbamate in Alcoholic Beverages and Fermented Foods Sold in Korea

    OpenAIRE

    Ryu, Dayeon; Choi, Bogyoung; Kim, Eunjoo; Park, Seri; Paeng, Hwijin; Kim, Cho-il; Lee, Jee-yeon; Yoon, Hae Jung; Koh, Eunmi

    2015-01-01

    Ethyl carbamate (EC) classified as a probable human carcinogen (Group 2A) is naturally formed in alcoholic beverages and fermented foods during fermentation process and/or during storage. The objective of this study was to analyze EC in 34 food items including 14 alcoholic beverages and 20 fermented foods sold in Korea. Each food was collected from 18 supermarkets in 9 metropolitan cities in Korea, and then made into composite. According to food composition and alcohol content, samples were d...

  4. Modeling the vibrational spectrum of 4,4'-diphenylmethane- bis(methyl)carbamate

    Science.gov (United States)

    Shundalau, M. B.; Pitsevich, G. A.; Ksenofontov, M. A.; Umreiko, D. S.

    2010-07-01

    We present results of ab initio calculations of the structure and vibrational IR spectrum for 4,4'-diphenylmethane-bis(methyl)carbamate (DPMC). Calculations were carried out in the HF/6-311G approximation with subsequent force-field scaling. The calculated characteristics of the vibrational spectrum of DPMC show satisfactory agreement with experimental values, which permits them to be used in spectral and structural analysis

  5. Salicylanilide N-monosubstituted carbamates: Synthesis and in vitro antimicrobial activity.

    Science.gov (United States)

    Krátký, Martin; Vinšová, Jarmila

    2016-03-15

    The research of innovative antimicrobial agents represents a cutting edge topic. Hence, we synthesized and characterised novel salicylanilide N-monosubstituted carbamates. Twenty compounds were evaluated in vitro against eight bacterial strains and eight fungal species. The lowest minimum inhibitory concentrations (MICs) were found to be ⩽0.49μM. Genus Staphylococcus, including methicillin-resistant Staphylococcus aureus, and fungus Trichophyton mentagrophytes showed uniformly the highest rate of susceptibility, whilst Gram-negative bacteria and most of the fungi were less susceptible. A wide range of carbamates provided comparable or superior in vitro antimicrobial activity in comparison to established drugs. Interestingly, extended-spectrum β-lactamase producing strain of Klebsiella pneumoniae was inhibited with MICs starting from 31.25μM. With respect to Staphylococci, 2-[(4-bromophenyl)carbamoyl]-4-chlorophenyl phenylcarbamate exhibited the lowest MIC values (⩽0.98μM). 2-[(4-Bromophenyl)carbamoyl]-4-chlorophenyl benzylcarbamate showed the widest spectrum of antifungal action. The results indicate that some salicylanilide carbamates can be considered to be promising candidates for future investigation. PMID:26879856

  6. Preparation of sintered silver nanosheets by coating technique using silver carbamate complex

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Hee-Yong; Cha, Jae-Ryung; Gong, Myoung-Seon, E-mail: msgong@dankook.ac.kr

    2015-03-01

    This study describes a coating technique approach for large-scale preparation of sintered silver nanosheets whose lateral dimensions were controlled in the thickness range of 50–65 nm. These procedures involved coating water-soluble poly (vinyl alcohol) (PVA) and silver 2-ethylhexylcarbamate (Ag-EHC), as well as thermal reduction of a silver precursor by heating at 150 °C, followed by dissolving away the PVA layer with alcoholic water. When the silver carbamate layer on the PVA layer was heated to 150 °C, the silver carbamate layer was thermally reduced and directed to grow into uniform sintered nanosheets with aspect ratios as high as 1000. The multi-stacked PVA/Ag structures and sintered silver nanosheets were confirmed by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Measurements of the conductive property at room temperature indicated that these nanosheets were electrically continuous with a resistivity of approximately 7.3 × 10{sup −6} Ω cm. - Highlights: • A coating technique is used to make sintered Ag nanosheets. • PVA and silver carbamate act as a separation layer and a silver precursor. • The Ag nanosheets have thickness width 50–60 nm and width up to hundred μm. • The Ag nanosheets showed a resistivity of ca. 7.3 × 10{sup −6} Ω cm.

  7. RECOVERY OF URANIUM BY CYCLOALKYLDITHIO-CARBAMATE COMPLEXING

    Science.gov (United States)

    Neville, O.K.

    1959-06-30

    The separation of uranium-233 from an aqueous nitric acid solution of neutron irradiated thorium by selectively complexing the uranium is described. The separation is carried out by contacting the thorium solution with a non- aromatic organic dithiocarbamate selected from the group which consists of alkali and alkaline earth cycloalkyldithiocarbamates and recovering the resulting uranyl cycloalkyldithiocarbamate complex by organic solvent extraction such as with methyl ethyl ketone. The complexed uranium may be stripped from the separated organic phase by scrubbing with one normal nitric acid solution.

  8. Probabilistic assessment of the cumulative dietary acute exposure of the population of Denmark to organophosphorus and carbamate pesticides

    DEFF Research Database (Denmark)

    Jensen, Bodil Hamborg; Petersen, Annette; Christensen, Tue

    2009-01-01

    Organophosphorus and carbamate pesticides are acetylcholinesterase-inhibiting pesticides and as such have a common mode of action. We assessed the cumulative acute exposure of the population of Denmark to 25 organophosphorus and carbamate pesticide residues from the consumption of fruit, vegetables...... and cereals. The probabilistic approach was used in the assessments. Residue data obtained from the Danish monitoring programme carried out in the period 2004-2007, which included 6704 samples of fruit, vegetables and cereals, were used in the calculations. Food consumption data were obtained from...... the nationwide dietary survey conducted in 2000-2002. Contributions from 43 commodities were included in the calculations. We used the relative potency factor (RPF) approach to normalize the toxicity of the various organophosphorus and carbamate pesticides to the two index compounds chlorpyriphos...

  9. Role of B-esterases in assessing toxicity of organophosphorus (chlorpyrifos, malathion) and carbamate (carbofuran) pesticides to Daphnia magna.

    Science.gov (United States)

    Barata, Carlos; Solayan, Arun; Porte, Cinta

    2004-02-10

    In this study, the cladoceran Daphnia magna was exposed to two model organophosphorous and one carbamate pesticides including malathion, chlorpyrifos and carbofuran to assess acetylcholinesterase (AChE) and carboxylesterase (CbE) inhibition and recovery patterns and relate those responses with individual level effects. Our results revealed differences in enzyme inhibition and recovery patterns among the studied esterase enzymes and pesticides. CbE was more sensitive to organophosphorous than AChE, whereas both CbE and AChE showed equivalent sensitivities to the carbamate carbofuran. Recovery patterns of AChE and CbE activities following exposure to the studied pesticides were similar with 80-100% recoveries taking place 12 and 96 h after exposure to organophosphorous and carbamates pesticides, respectively. The physiological role of AChE and CbE inhibition patterns in Daphnia was examined by using organophosphorous and carbamate compounds alone and with specific inhibitors of CbE. Under exposure to organophosphorous pesticides, survival of Daphnia juveniles was impaired at AChE inhibition levels higher than 50% whereas under exposure to the carbamate carbofuran low levels of AChE inhibition affected mortality. Inhibition of CbE by 80-90% increased toxicity to organophosphorous and carbamate pesticides by up to two- and four-fold, respectively. Our results suggest that both AChE and CbE enzymes are involved in determining toxicity of Daphnia to the studied chemicals and that AChE inhibition levels higher than 50% can be considered of environmental concern to Daphnia species. PMID:15036868

  10. The role of kaolin particles in the performance of a carbamate-based biocide for water bacterial control

    OpenAIRE

    Maria Olivia Pereira; Maria João Vieira; Melo, Luis F.

    2002-01-01

    The influence of kaolin particles on the activity of Pseudomonas fuorescens and on the efficacy of a carbamate-based biocide was investigated. The results indicated that kaolin particles stimulated the activity of the bacteria for all buffered pH values studied (5, 7, and 9); this effect being more evident for the tests carried out at pH 5 and 9. The presence of the clay in P. fuorescens suspensions decreased the efficiency of disinfection of the carbamate. The results also showed that kaolin...

  11. Nonracemic, chiral homoenolate reagents derived from (cycloalk-1-enyl)methyl carbamates and evaluation of their configurational stabilities

    DEFF Research Database (Denmark)

    Özlügedik, M.; Kristensen, Jesper Langgaard; Wibbeling, B.;

    2002-01-01

    the products 19/ent-19. Lithiated 2-unsubstituted (cyclopent-1-enyl) methyl carbamates, such as 11a or 11h, epimerise rapidly at -78 °C and the thermodynamically controlled ratio is opposite to the kinetically achieved ratio. High configurational stability was found for the 2-methylcycloalk-1-enyl......-methylcyclopentenyl)methyl and (2-methyl-cyclohexenyl)methyl reagents, established the (1S) configuration of the major lithium compound. Thus, the kinetically controlled deprotonation of the corresponding allyl carbamates removes the (pro-S) proton. Overall, a simple method for the enantioselective synthesis of...

  12. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

    OpenAIRE

    Li-Si Huang; Fei He; Hui Huang; Xiao-Yong Zhang; Shu-Hua Qi

    2012-01-01

    Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6), (−)-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7), (−)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendrane...

  13. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

    OpenAIRE

    Huang, Li-Si; He, Fei; Huang, Hui; Zhang, Xiao-yong; Qi, Shu-Hua

    2012-01-01

    Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6), (−)-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7), (−)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendranediol (9) were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. ...

  14. In Situ Blood-Brain Barrier Permeability of a C-10 Paclitaxel Carbamate

    OpenAIRE

    Ballatore, Carlo; Zhang, Bin; Trojanowski, John Q.; Lee, Virginia M.-Y.; Smith, Amos B.

    2008-01-01

    We report the synthesis and blood-brain barrier (BBB) permeability of 14C-CNDR-29, a paclitaxel C-10 carbamate derivative shown to be devoid of P-glycoprotein (Pgp)-interactions, in an in situ mouse brain perfusion model, in comparison with 14C-paclitaxel. The results presented reveal a 3–4 fold higher BBB-permeability for the C-10 modified taxane compared to paclitaxel. These results support the notion that circumvention of Pgp-mediated efflux can lead to higher BBB-permeability. Further stu...

  15. Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography

    Science.gov (United States)

    Belisle, A.A.; Swineford, D.M.

    1988-01-01

    A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.

  16. toxicological effect of carbamate (methavin) on some biochemical activities in white rats

    International Nuclear Information System (INIS)

    this work aims to study the toxic effect, which resulted from the direct or indirect exposure to the applied insecticide (methomyl), which was formerly known as lannate, that belongs to carbamate group. this study includes the determination of the effect of the methomyl on some biochemical activities in white rats as well as the changes in some hormonal levels. since the mentioned insecticide used in egypt from many years ago, which necessitated numerous studies on its effect to various organs of the human body by treating some animals which are closely similar to human construction

  17. Radioiodinated 2-nitrobenzyl carbamates as bioreductive alkylating agents for tissue hypoxia

    International Nuclear Information System (INIS)

    Three N-methylcarbamates of iodonitrobenzyl alcohols (4-iodo-2-nitrobenzyl alcohol 2, 5-iodo-2-nitrobenzyl alcohol 3 and 4-iodo-2,6-dinitrobenzyl alcohol 4) bearing [125I] have been prepared and characterized for their lipophilicity, their reduction potentials and the in vivo lability of the radioiodine in healthy mice. Based upon these results, 2 and 4 were tested in tumour-bearing mice showing limited uptake of radioactivity in tumours and a tumour-to-blood ratio of less than 1. Consequently these particular carbamates are not satisfactory as hypoxia imaging agents. (Author)

  18. Synthesis of dimethyl carbonate from methyl carbamate and methanol using a Fixed-Bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D. [Zaozhuang University, College of Chemistry, Chemical Engineering and Materials Science, Zaozhuang (China); Zhang, X. [Zaozhuang University, College of Chemistry, Chemical Engineering and Materials Science, Zaozhuang (China); Chinese Academy of Sciences, Institute of Coal Chemistry, State Key Laboratory of Coal Conversion, Taiyuan (China); Wei, W.; Sun, Y. [Chinese Academy of Sciences, Institute of Coal Chemistry, State Key Laboratory of Coal Conversion, Taiyuan (China)

    2012-12-15

    Several mixed oxide catalysts were prepared by coprecipitation for dimethyl carbonate (DMC) synthesis from methyl carbamate and methanol. During the batch process, the DMC yield was below 35 %. In order to minimize the unfavorable thermodynamic equilibrium and side reactions for the DMC synthesis, a fixed-bed reactor was designed. A maximum DMC yield of {proportional_to} 73 % could be realized over a ZnO-Al{sub 2}O{sub 3} catalyst. The effects of reaction conditions for this type of reactor were investigated in detail. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Radiosynthesis and ex vivo evaluation of [11C-carbonyl]carbamate- and urea-based monoacylglycerol lipase inhibitors

    International Nuclear Information System (INIS)

    Introduction: Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) are the two primary enzymes that regulate the tone of endocannabinoid signaling. Although new PET radiotracers have been discovered for imaging FAAH in vivo, no such radiotracer exists for imaging MAGL. Here we report the radiosynthesis of five candidate MAGL radiotracers and their ex vivo evaluations in mice and rats. Methods: Candidate carbamate and urea MAGL inhibitors were radiolabeled at the carbonyl position by [11C]CO2 fixation. Radiotracers were administered (tail-vein injection) to rodents and brain uptake of radioactivity measured at early and late time points ex vivo. Specificity of uptake was explored by pretreatment with unlabeled inhibitors (2 mg/kg, ip) 30 min prior to radiotracer administration. Results: All five candidate MAGL radiotracers were prepared in high specific activity (> 65 GBq/μmol) and radiochemical purity (> 98%). Moderate brain uptake (0.2–0.8 SUV) was observed for each candidate while pretreatment did not reduce uptake for four of the five tested. For two candidates ([11C]12 and [11C]14), high retention of radioactivity was observed in the blood (ca. 10 and 4 SUV at 40 min) which was blocked by pretreatment with unlabeled inhibitors. The most promising candidate, [11C]18, demonstrated moderate brain uptake (ca. 0.8 SUV) which showed circa 50% blockade by pretreatment with unlabeled 18. Conclusion: One putative and four reported potent and selective MAGL inhibitors have been radiolabeled via [11C]CO2 fixation as radiotracers for this enzyme. Despite the promising in vitro pharmacological profile, none of the five candidate radiotracers exhibited in vivo behavior suitable for PET neuroimaging

  20. UPLC-MS/MS测定中药材中19种氨基甲酸酯农药残留量%Determination of Nineteen Carbamate Pesticides in Chinese Medicinal Materials by UPLC-MS/MS

    Institute of Scientific and Technical Information of China (English)

    张燕; 杨钊; 金红宇; 孙磊; 李欣荣; 吴爱英

    2011-01-01

    OBJECTIVE To establish a method for the determination of 19 carbamate pesticides in Chinese medicinal materials by UPLC triple-quadrupole tandem mass spectrometer.METHODS The samples were determinated by multi-reactions monitoring (MRM) technology.The separation was performed on a Waters ACQUITY UPLC (R) BEH C18 column with acetonitrile -0.1% formic acid ( 1:1 ) with a flow rate of 0.2 mL min-1.Ion mode was set as ESI+.RESULTS The standard curves of the 19 carbamate pesticides showed good linearity over the concentration range of 1.0 - 100 μg · L-1 (r =0.994 7 -0.999 7), respectively.The LODs of 19 carbamate pesticides were in the range of 0.02 - 0.46 μg · L- 1 and the average recoveries were 73.2% - 119.7% at three levels.CONCLUSION The method is rapid, sensitive and suitable for the determination of 19 carbamate pesticides in Chinese medicinal materials.%目的 建立测定中药材中19种氨基甲酸酯农药残留量的超高效液相-串联四级杆质谱方法.方法 多反应监测模式测定,以Waters ACQUITY UPLC(R) BEH C18进行分离,乙腈-0.1%甲酸溶液(1:1),流速:0.2 mL·min-1.离子化模式:ESI+.结果 19种农药测定的线性范围在1.0~100.0 μg·L-1之间,r分别在0.994 7~0.999 7之间,检出质量浓度分别在0.02~0.46μg·L-1之间,3个水平的回收率分别在73.2%~119.7%之间.结论 该方法快速、准确、灵敏,可用于中药材中氨基甲酸酯类农药残留的测定.

  1. 液相色谱串联质谱法测定白酒中氨基甲酸乙酯的方法探讨%Determination of Ethyl Carbamate in White Spirit by Liquid Chromatography-tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    吴宏萍; 杨红文; 魏云; 吴丽华; 薛锡佳; 张娇娇; 锁震南; 时玉英

    2015-01-01

    建立了直接测定白酒中氨基甲酸乙酯的液相色谱-串联质谱(LC-MS-MS)分析方法,采用Poroshell 120EC-C18色谱柱,以0.1%乙酸水溶液和乙腈为流动相(体积比9∶1)进行洗脱,流速为0.2mL/min;在电喷雾电离(ESI)正离子模式下,采用多重反应监测模式进行检测,线性范围为5~500μg/L;检出限为1μg/L,定量限为5μg/L;加标回收率为89%~106%,相对标准偏差均不大于3.9%。该法快捷、准确、重现性好。%A method for the direct determination of ethyl carbamate in White spirit was established by liquid chromatography with tandem mass spectrometry (LC-MS-MS).The LC separation was performed on a Poroshell 120 EC-C18 column (50mm × 3.0mm,2.7μm)by using 0.1%(v/v) acetic acid aqueous solution and acetonitrile as mobile phases (v/v 9∶1) at a flow rate of 0.2mL/min. The analytes were detected by tandem mass spectro-metry under the positive ion mode with the electrospray ionization (ESI) source and in the multiple reaction monitoring (MRM)mode. Under the optimized conditions ,the calibration curve was linear in the ranges of 5~500μg/L for the ethyl carbamate with the detection limits of 1μg/L and the limit of quantification of 5μg/L. The recoveries of the ethyl carbamate was in the range of 89%and 106%with the relative standard deviations not more than3.9%. The developed method is simple ,rapid and accurate, and suitable for the quality control of ethyl carbamate in White spirit.

  2. The P450 CYP6Z1 confers carbamate/pyrethroid cross-resistance in a major African malaria vector beside a novel carbamate-insensitive N485I acetylcholinesterase-1 mutation.

    Science.gov (United States)

    Ibrahim, Sulaiman S; Ndula, Miranda; Riveron, Jacob M; Irving, Helen; Wondji, Charles S

    2016-07-01

    Carbamates are increasingly used for vector control notably in areas with pyrethroid resistance. However, a cross-resistance between these insecticides in major malaria vectors such as Anopheles funestus could severely limit available resistance management options. Unfortunately, the molecular basis of such cross-resistance remains uncharacterized in An. funestus, preventing effective resistance management. Here, using a genomewide transcription profiling, we revealed that metabolic resistance through upregulation of cytochrome P450 genes is driving carbamate resistance. The P450s CYP6P9a, CYP6P9b and CYP6Z1 were the most upregulated detoxification genes in the multiple resistant mosquitoes. However, in silico docking simulations predicted CYP6Z1 to metabolize both pyrethroids and carbamates, whereas CYP6P9a and CYP6P9b were predicted to metabolize only the pyrethroids. Using recombinant enzyme metabolism and inhibition assays, we demonstrated that CYP6Z1 metabolizes bendiocarb and pyrethroids, whereas CYP6P9a and CYP6P9b metabolize only the pyrethroids. Other upregulated gene families in resistant mosquitoes included several cuticular protein genes suggesting a possible reduced penetration resistance mechanism. Investigation of the target-site resistance in acetylcholinesterase 1 (ace-1) gene detected and established the association between the new N485I mutation and bendiocarb resistance (odds ratio 7.3; P carbamate resistance and improve the design of effective resistance management strategies to control this malaria vector. PMID:27135886

  3. Vapor Pressure, Vaporization Enthalpy, Standard Enthalpy of Formation and Standard Entropy of n-Butyl Carbamate

    Institute of Scientific and Technical Information of China (English)

    Zuoxiang Zeng⁎; Zhihong Yang; Weilan Xue⁎; Xiaonan Li

    2014-01-01

    The vapor pressures of n-butyl carbamate were measured in the temperature range from 372.37 K to 479.27 K and fitted with Antoine equation. The compressibility factor of the vapor was calculated with the Virial equation and the second virial coefficient was determined by the Vetere model. Then the standard enthalpy of vaporization for n-butyl carbamate was estimated. The heat capacity was measured for the solid state (299.39–324.2 K) and liquid state (336.65–453.21 K) by means of adiabatic calorimeter. The standard en-thalpy of formationΔfHϴ[crystal (cr),298.15 K] and standard entropy Sϴ(crystal,298.15 K) of the sub-stance were calculated on the basis of the gas-phase standard enthalpy of formationΔfHϴ(g,298.15 K) and gas-phase standard entropy Sϴ(g,298.15 K), which were estimated by the Benson method. The results are acceptable, validated by a thermochemical cycle.

  4. Blackberry subjected to in vitro gastrointestinal digestion affords protection against Ethyl Carbamate-induced cytotoxicity.

    Science.gov (United States)

    Chen, Wei; Xu, Yang; Zhang, Lingxia; Su, Hongming; Zheng, Xiaodong

    2016-12-01

    Ethyl Carbamate (EC) was detected in many fermented foods. Previous studies indicated that frequent exposure to ethyl carbamate may increase the risk to suffer from cancers. Blackberry is rich in polyphenols and possesses potent antioxidant activity. This study aims to investigate the protective effect of blackberry homogenates produced before (BH) and after in vitro simulated gastrointestinal digestion (BD) on EC-induced toxicity in Caco-2 cells. Our results showed that blackberry homogenates after digestion (BD) was more effective than that before digestion (BH) in ameliorating EC-induced toxicity in Caco-2 cells. Further investigation revealed that BD remarkably attenuated EC-induced toxicity through restoring mitochondrial function, inhibiting glutathione depletion and decreasing overproduction of intracellular reactive oxygen species. Additionally, LC-MS result implied that the better protective capacity of BD may be related to the increased content of two anthocyanins (cyanidin-3-glucoside and cyanidin-3-dioxalyglucoside). Overall, the present study may give implication to prevent EC-induced health problem. PMID:27374576

  5. Demonstration of a functional requirement for the carbamate nitrogen of ribulosebisphosphate carboxylase/oxygenase by chemical rescue

    International Nuclear Information System (INIS)

    Ribulosebisphosphate carboxylase/oxygenase is reversibly activated by the reaction of Co2 with a specific lysyl residue to form a carbamate that coordinates an essential Mg2+ cation. Surprisingly, the Lys191→Cys mutant protein, in the presence of Co2 and Mg2+ exhibits tight binding of the reaction intermediate analogue 2-carboxyarabinitol bisphosphate a property normally equated with effective coordination of the Mg2+ by the carbamate. Catalytic ineptness of the Cys191 mutant protein, despite its ability to coordinate Mg2+ properly, might be due to the absence of the carbamate nitrogen. To investigate this possibility, the authors have evaluated the ability of exogenous amines to restore catalytic activity to the mutant protein. Significantly, the Cys191 protein manifests ribulose bisphosphate dependent fixation of 14CO2 when incubated with aminomethanewsulfonate but not ethanesulfonate. This novel activity reflects a Km value for ribulose bisphosphate which is not markedly perturbed relative to wild-type enzyme, a Km for Mg2+ which is in fact decreased 10-fold, and rate saturation with respect to aminomethanesulfonate. Chromatographic and spectrophotometric analyses reveal the product of CO2 fixation to be D-3-phosphoglycerate while turnover of [1-3H]ribulose bisphosphate into [3H]phosphoglycolate confirms oxygenase activity. The authors conclude that aminomethanesulfonate restored ribulosebisphosphate carboxylase/oxygenase activities to the Cys191 mutant protein by providing a nitrogenous function which satisfies a catalytic demand normally met by the carbamate nitrogen of Lys191

  6. High-performance liquid chromatography multiresidue method for the determination of N-methyl carbamates in fruit and vegetable juices.

    Science.gov (United States)

    Sánchez-Brunete, Consuelo; Albero, Beatriz; Tadeo, José Luis

    2004-11-01

    A rapid multiresidue method has been developed for the analysis of N-methylcarbamate insecticides (oxamyl, methomyl, propoxur, carbofuran, carbaryl, and methiocarb) in fruit and vegetable juices. The method is based on the adsorption of the N-methyl carbamates in Florisil and the subsequent extraction of pesticides using a low volume of acetone. Residue levels in juice were determined by reversed-phase high-performance liquid chromatography with fluorescence detection after postcolumn derivatization. The separation of carbamates is performed on a C8 column with water-methanol as mobile phase. Recovery studies were performed at 500-, 100-, and 10-ng/ml fortification levels, and average recoveries obtained for carbamates ranged from 79 to 109%, with relative standard deviations between 1.4 and 9.9%. The method was found to be linear over the range assayed from 10 to 1,000 ng/ml, and the detection limits for carbamates varied from 0.8 to 1.9 ng/ml. PMID:15553643

  7. Benchmark Dose Analysis from Multiple Datasets: The Cumulative Risk Assessment for the N-Methyl Carbamate Pesticides

    Science.gov (United States)

    The US EPA’s N-Methyl Carbamate (NMC) Cumulative Risk assessment was based on the effect on acetylcholine esterase (AChE) activity of exposure to 10 NMC pesticides through dietary, drinking water, and residential exposures, assuming the effects of joint exposure to NMCs is dose-...

  8. Structural relaxation accompanied by photo-induced chromatic phase transition of polydiacetylenes with butylene-N-difluorophenyl carbamate side chains

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Yuuki; Sakamoto, Naoya; Kokado, Ryousuke; Kajimoto, Naoshi; Izumi, Yuuichiro [Department of Materials Science and Chemistry, Wakayama University, 930 Sakaedani, Wakayama (Japan); Itoh, Chihiro, E-mail: citoh@sys.wakayama-u.ac.jp [Department of Materials Science and Chemistry, Wakayama University, 930 Sakaedani, Wakayama (Japan)

    2013-01-15

    We have studied the phase transition of poly-5,7-dodecadiyne-1,12-diol bis[2,4-difluorophenyl carbamate] (PDA-2,4-DFPC) and poly-5,7-dodecadiyne-1,12-diol bis[3,4-difluorophenyl carbamate] (PDA-3,4-DFPC) by visible reflection spectroscopy and mid-infrared absorption spectroscopy. Both PDA-2,4-DFPC and PDA-3,4-DFPC show the reflection spectra characterized by a sharp peak at around 1.9 eV at room temperature. While PDA-3,4-DFPC shows thermochromic phase transition to the phase showing the reflection spectrum with a peak around 2.2 eV above 120 Degree-Sign C, PDA-2,4-DFPC shows no abrupt change of the reflection spectrum. However, PDA-2,4-DFPC shows drastic change of the reflection spectrum under 532-nm CW-laser excitation. Based on these results, we can draw the following two conclusions. First, the phase transition behavior of PDA can be controlled by modifying the side-chain structure. Second, we demonstrate that thermally inaccessible phase of PDA is induced by the photo-excitation. By measuring mid-infrared absorption of PDAs, we elucidated that conformational change of side chains is accompanied with the phase transition. Based on the results, we discussed the role of the side chain in the phase transition. - Highlights: Black-Right-Pointing-Pointer We have synthesized polydiacetylene (PDA) with difluorophenyl carbamate side chain. Black-Right-Pointing-Pointer PDAs show distinct phase transition (PT) depending on the side-chain structure. Black-Right-Pointing-Pointer PDA with 3,4-difluorophenyl carbamate shows PT by thermal stimulation. Black-Right-Pointing-Pointer However, PDA with 2,4-difluorophenyl carbamate shows PT only under photo-excitation.

  9. Utilization of charge-transfer complexation for the detection of carcinogenic substances in foods: Spectroscopic characterization of ethyl carbamate with some traditional π-acceptors

    Science.gov (United States)

    Adam, Abdel Majid A.; Refat, Moamen S.; Saad, Hosam A.

    2013-04-01

    The study of toxic and carcinogenic substances in foods represents one of the most demanding areas in food safety, due to their repercussions for public health. One potentially toxic compound for humans is ethyl carbamate (EC). EC is a multi-site genotoxic carcinogen of widespread occurrence in fermented foods and alcoholic beverages. Structural and thermal stability of charge-transfer complexes formed between EC as a donor with quinol (QL), picric acid (PA), chloranilic acid (CLA), p-chloranil (p-CHL) and 1,3-dinitrobenzene (DNB) as acceptors were reported. Elemental analysis (CHN), electronic absorption spectra, photometric titration, IR, and 1H NMR spectra show that the interaction between EC and acceptors was stabilized by hydrogen bonding, via a 1:1 stoichiometry. Thermogravimetric (TG) analysis indicates that the formation of molecular CT complexes was stable, exothermic and spontaneous. Finally, the CT complexes were screened for their antibacterial and antifungal activities. The results indicated that the [(EC)(QL)] complex exhibited strong antimicrobial activities against various bacterial and fungal strains compared with standard drugs.

  10. Enhanced anti-HIV-1 activity of G-quadruplexes comprising locked nucleic acids and intercalating nucleic acids

    DEFF Research Database (Denmark)

    Pedersen, Erik Bjerregaard; Nielsen, Jakob Toudahl; Nielsen, Claus; Filichev, Vyacheslav V

    2011-01-01

    Two G-quadruplex forming sequences, 50-TGGGAG and the 17-mer sequence T30177, which exhibit anti-HIV-1 activity on cell lines, were modified using either locked nucleic acids (LNA) or via insertions of (R)-1-O-(pyren-1-ylmethyl)glycerol (intercalating nucleic acid, INA) or (R)-1-O-[4-(1-pyrenylet......Two G-quadruplex forming sequences, 50-TGGGAG and the 17-mer sequence T30177, which exhibit anti-HIV-1 activity on cell lines, were modified using either locked nucleic acids (LNA) or via insertions of (R)-1-O-(pyren-1-ylmethyl)glycerol (intercalating nucleic acid, INA) or (R)-1-O-[4......-(1-pyrenylethynyl)phenylmethyl]glycerol (twisted intercalating nucleic acid, TINA). Incorporation of LNA or INA/TINA monomers provide as much as 8-fold improvement of anti-HIV-1 activity. We demonstrate for the first time a detailed analysis of the effect the incorporation of INA/TINA monomers in quadruplex forming...... of the 50-phosphate inhibits dimerisation of this G-quadruplex as a result of negative charge–charge repulsion. Contrary to that, we found that attachment of the 50-O-DMT-group produced a more active 17-mer sequence that showed signs of aggregation—forming multimeric G-quadruplex species in solution...

  11. From immunotoxicity to carcinogenicity: the effects of carbamate pesticides on the immune system.

    Science.gov (United States)

    Dhouib, Ines; Jallouli, Manel; Annabi, Alya; Marzouki, Soumaya; Gharbi, Najoua; Elfazaa, Saloua; Lasram, Mohamed Montassar

    2016-05-01

    The immune system can be the target of many chemicals, with potentially severe adverse effects on the host's health. In the literature, carbamate (CM) pesticides have been implicated in the increasing prevalence of diseases associated with alterations of the immune response, such as hypersensitivity reactions, some autoimmune diseases and cancers. CMs may initiate, facilitate, or exacerbate pathological immune processes, resulting in immunotoxicity by induction of mutations in genes coding for immunoregulatory factors and modifying immune tolerance. In the present study, direct immunotoxicity, endocrine disruption and inhibition of esterases activities have been introduced as the main mechanisms of CMs-induced immune dysregulation. Moreover, the evidence on the relationship between CM pesticide exposure, dysregulation of the immune system and predisposition to different types of cancers, allergies, autoimmune and infectious diseases is criticized. In addition, in this review, we will discuss the relationship between immunotoxicity and cancer, and the advances made toward understanding the basis of cancer immune evasion. PMID:26988364

  12. Occurrence and Distribution of Carbamate Pesticides and Metalaxyl in Southern Ontario Surface Waters 2007-2010.

    Science.gov (United States)

    Struger, John; Grabuski, Josey; Cagampan, Steve; Sverko, Ed; Marvin, Chris

    2016-04-01

    Surface water sampling in 2007-2010 measured the occurrence of carbamates and metalaxyl during base flow conditions and wet weather events in southern Ontario surface waters. Carbaryl, metalaxyl and pirimicarb were the most frequently detected compounds. In 2008 these three compounds were detected in over 50 % of the samples. Overall mean concentrations of carbaryl and metalaxyl over the course of the study (2007-2010) were 15 and 18 ng/L, respectively. Elevated concentrations of carbaryl (~100 to ~950 ng/L) appeared associated with wet weather (high flow) events, while highest concentrations of metalaxyl (~20-1330 ng/L) were correlated with base flow conditions. We attributed these observations as the result of runoff of carbaryl from the watershed during rain events, while metalaxyl contamination may have resulted primarily from spray drift. PMID:26754544

  13. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata.

    Science.gov (United States)

    Huang, Li-Si; He, Fei; Huang, Hui; Zhang, Xiao-Yong; Qi, Shu-Hua

    2012-01-01

    Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6), (-)-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7), (-)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendranediol (9) were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was rarely found in marine natural compounds, and 7 showed moderate antibacterial activity. The possible biosynthesis routes of 1-5 were conjectured. PMID:22423284

  14. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

    Directory of Open Access Journals (Sweden)

    Li-Si Huang

    2012-01-01

    Full Text Available Five carbamate derivatives, obtucarbamates C and D (1, 2, dimethyl ((carbonylbis(azanediylbis(2-methyl-5,1-phenylenedicarbamate (3, obtucarbamates A and B (4, 5, and four aromadendrane-type sesquiterpenoids, (+-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6, (−-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7, (−-4α,10β-aromadendranediol (8, (+-4β,10β-aromadendranediol (9 were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was rarely found in marine natural compounds, and 7 showed moderate antibacterial activity. The possible biosynthesis routes of 1–5 were conjectured.

  15. Solubility improvement of an anthelmintic benzimidazole carbamate by association with dendrimers

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, L.; Sigal, E.; Santo, M., E-mail: msanto@exa.unrc.edu.ar [Departamento de Fisica, Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto (Argentina); Otero, L.; Silber, J. J. [Departamento de Quimica. Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto, Rio Cuarto (Argentina)

    2011-10-15

    The improvement of aqueous solubility of methyl (5-[propylthio]-1H-benzimidazole-2-yl) carbamate, albendazole (ABZ) using polyamidoamine (PAMAM) dendrimers as solubility enhancers was investigated. Full generation PAMAM dendrimers with amine terminal groups, (G3), with hydroxyl terminal groups (G3OH) and half generation PAMAM dendrimers with carboxylate terminal groups (G2.5 and G3.5), were chosen for this study. The nature of dendrimer-ABZ association was investigated by UV absorption, fluorescence emission measurements and by {sup 1}H-NMR spectroscopy. The results obtained show that these polymeric structures have the capacity to enhance the solubility of ABZ, both lipophilic and specific hydrogen bond interactions contributing to the guest-host association. Although all studied dendrimers have hydrophobic internal nanoenvironments with similar dimensions, their surfaces differ significantly and the nature and the localization of the interactions involved in ABZ-dendrimer association depend on the type of terminal groups. (author)

  16. A general method for tritium labelling of benzimidazole carbamates by catalytic exchange in dioxane solutions

    Energy Technology Data Exchange (ETDEWEB)

    Lacey, E. (Commonwealth Scientific and Industrial Research Organization, Glebe, NSW (Australia). Div. of Animal Health, McMaster Lab.); Dawson, M. (Sydney Univ. (Australia). Dept. of Pharmacy); Long, M.A.; Than, C. (New South Wales Univ., Kensington (Australia). School of Chemistry)

    1989-12-01

    Benzimidazole carbamates (BZCs) act as inhibitors of the tubulin-microtubule equilibria in eukaryotic organisms. Recently drug resistance to this class of compounds in helminth parasites has been shown to be due to a reduced ability of resistant tubulin to bind BZCs. In order to quantitate the nature of the tubulin-BZC interaction a general method for the specific tritium labelling of BZCs has been developed. The BZCs: mebendazole, oxfendazole, parbendazole, oxibendazole, albendazole and fenbendazole were labelled by catalytic exchange using palladium on calcium carbonate in pure dioxane at 60{sup 0}C under tritium gas. The position of label incorporation for tritiated albendazole was determined by tritium-NMR as the 4-position of benzimadazole nucleus. The yields for individual BZCs varied from 8 to 68% for a range of specific activity of 0.44 to 13.4 Ci/mmole. (author).

  17. A general method for tritium labelling of benzimidazole carbamates by catalytic exchange in dioxane solutions

    International Nuclear Information System (INIS)

    Benzimidazole carbamates (BZCs) act as inhibitors of the tubulin-microtubule equilibria in eukaryotic organisms. Recently drug resistance to this class of compounds in helminth parasites has been shown to be due to a reduced ability of resistant tubulin to bind BZCs. In order to quantitate the nature of the tubulin-BZC interaction a general method for the specific tritium labelling of BZCs has been developed. The BZCs: mebendazole, oxfendazole, parbendazole, oxibendazole, albendazole and fenbendazole were labelled by catalytic exchange using palladium on calcium carbonate in pure dioxane at 600C under tritium gas. The position of label incorporation for tritiated albendazole was determined by tritium-NMR as the 4-position of benzimadazole nucleus. The yields for individual BZCs varied from 8 to 68% for a range of specific activity of 0.44 to 13.4 Ci/mmole. (author)

  18. Synthesis of kenaf cellulose carbamate and its smart electric stimuli-response.

    Science.gov (United States)

    Gan, Sinyee; Piao, Shang Hao; Choi, Hyoung Jin; Zakaria, Sarani; Chia, Chin Hua

    2016-02-10

    Cellulose carbamate (CC) was produced from kenaf core pulp (KCP) via a microwave reactor-assisted method. The formation of CC was confirmed by Fourier transform infrared spectroscopy and nitrogen content analysis. The degree of substitution, zeta potential and size distribution of CC were also determined. The CC was characterized with scanning electron microscopy, X-ray diffraction and thermogravimetry analysis. The CC particles were then dispersed in silicone oil to prepare CC-based anhydrous electric stimuli-responsive electrorheological (ER) fluids. Rhelogical measurement was carried out using rotational rheometer with a high voltage generator in both steady and oscillatory shear modes to examine the effect of electric field strength on the ER characteristics. The results showed that the increase in electric field strength has enhanced the ER properties of CC-based ER fluid due to the chain formation induced by electric polarization among the particles. PMID:26686181

  19. Assessment of Organophosphate and Carbamate Pesticide Residues in Cigarette Tobacco with a Novel Cell Biosensor

    Directory of Open Access Journals (Sweden)

    Spiridon Kintzios

    2008-04-01

    Full Text Available The conventional analysis of pesticide residues in analytical commodities, such as tobacco and tobacco products is a labor intensive procedure, since it is necessary to cover a wide range of different chemicals, using a single procedure. Standard analysis methods include extensive sample pretreatment (with solvent extraction and partitioning phases and determination by GC and HPLC to achieve the necessary selectivity and sensitivity for the different classes of compounds under detection. As a consequence, current methods of analysis provide a limited sample capacity. In the present study, we report on the development of a novel cell biosensor for detecting organophosphate and carbamate pesticide residues in tobacco. The sensor is based on neuroblastoma N2a cells and the measurement of changes of the cell membrane potential, according to the working principle of the Bioelectric Recognition Assay (BERA. The presence of pesticide residues is detected by the degree of inhibition of acetylcholine esterase (AChE. The sensor instantly responded to both the organophoshate pesticide chlorpyriphos and the carbamate carbaryl in a concentration-dependent pattern, being able to detect one part per billion (1 ppb. Additionally, tobacco leaf samples (in blended dry form were analyzed with both the novel biosensor and conventional methods, according to a double-blind protocol. Pesticide residues in tobacco samples caused a considerable cell membrane hyperpolarization to neuroblastoma cells immobilized in the sensor, as indicated by the increase of the negative sensor potential, which was clearly distinguishable from the sensor’s response against pesticide-free control samples. The observed response was quite reproducible, with an average variation of +5,6%. Fluorescence microscopy observations showed that treatment of the cells with either chlorpyrifos or carbaryl was associated with increased [Ca2+]cyt . The novel biosensor offers fresh

  20. Novel Cholinesterase Inhibitors Based on O-Aromatic N,N-Disubstituted Carbamates and Thiocarbamates

    Directory of Open Access Journals (Sweden)

    Martin Krátký

    2016-02-01

    Full Text Available Based on the presence of carbamoyl moiety, twenty salicylanilide N,N-disubstituted (thiocarbamates were investigated using Ellman’s method for their ability to inhibit acetylcholinesterase (AChE and butyrylcholinesterase (BChE. O-Aromatic (thiocarbamates exhibited weak to moderate inhibition of both cholinesterases with IC50 values within the range of 1.60 to 311.0 µM. IC50 values for BChE were mostly lower than those obtained for AChE; four derivatives showed distinct selectivity for BChE. All of the (thiocarbamates produced a stronger inhibition of AChE than rivastigmine, and five of them inhibited BChE more effectively than both established drugs rivastigmine and galantamine. In general, 5-chloro-2-hydroxy-N-[4-(trifluoromethyl-phenyl]benzamide, 2-hydroxy-N-phenylbenzamide as well as N-methyl-N-phenyl carbamate derivatives led to the more potent inhibition. O-{4-Chloro-2-[(4-chlorophenylcarbamoyl]phenyl} dimethylcarbamothioate was identified as the most effective AChE inhibitor (IC50 = 38.98 µM, while 2-(phenylcarbamoylphenyl diphenylcarbamate produced the lowest IC50 value for BChE (1.60 µM. Results from molecular docking studies suggest that carbamate compounds, especially N,N-diphenyl substituted representatives with considerable portion of aromatic moieties may work as non-covalent inhibitors displaying many interactions at peripheral anionic sites of both enzymes. Mild cytotoxicity for HepG2 cells and consequent satisfactory calculated selectivity indexes qualify several derivatives for further optimization.

  1. Novel Preparation of Methoxy Carbamates of 1-Protected Indole- 3-methylamines as Precursor of Indole-3-methylamine

    Institute of Scientific and Technical Information of China (English)

    SONG,Hao; XIN,Jun-Guo; WANG,Yin; CHEN,Wei; YANG,Jun; QIN,Yong

    2004-01-01

    @@ Indole-3-methylamine (1) has been well demonstrated to be a very useful intermediate as a pharmaceutical building block and starting material for syntheses of phytoalexins.[1] The instability of indole-3-methylamine (1) has undoubtedly restricted its application in synthetic chemistry. Hofmann rearrangement that directly converts carboxamides to alky carbamates in the presence of alcohol required unexceptionally a strong base,[2] which devaluated the possible usefulness of Hofmann rearrangement in preparation of base sensitive amines, especially for the preparation of unstable indole-3-methylamine (1). Herein we would like to report a convenient method for the preparation of alkyl carbamates of 1-protected indole-3-methylamines (4) via the diacetoxyiodobenzene (DIB) promoted Hofmann rearrangement under neutral condition.

  2. Solid-phase extraction of flavonoids in honey samples using carbamate-embedded triacontyl-modified silica sorbent.

    Science.gov (United States)

    Liu, Houmei; Zhang, Mingliang; Guo, Yong; Qiu, Hongdeng

    2016-08-01

    In this study, carbamate-embedded triacontyl-modified silica (Sil-CBM-C30) is successfully prepared and used as an efficient sorbent for solid-phase extraction. The extraction performance of the resultant sorbent is evaluated with five flavonoids including myricetin, quercetin, luteolin, kaempferol and isorhamnetin. Main parameters, which affect extraction efficiencies, are carefully investigated and optimized. Comparative experiments between Sil-CBM-C30 and commercial C18 sorbents indicate that the extraction efficiencies of the former one surpass the latter one. The modification of carbamate-embedded triacontyl group on surface of silica causes analytes extracted by hydrophobic, hydrogen bonding and π-π interactions. Under optimal conditions, good linearities and satisfied LODs and LOQs are achieved. The SPE-HPLC-DAD method is successfully developed and applied for the honey sample analysis. PMID:26988475

  3. 氨基甲酸酯清洁合成技术进展%Progress in clean synthesis of carbamates

    Institute of Scientific and Technical Information of China (English)

    谭学峰; 王越; 胡静; 马飞; 王公应

    2012-01-01

    综述了氨基甲酸酯清洁合成技术的发展现状和趋势,并对所用催化剂体系做了详细评述,认为碳酸酯胺解法是最具产业化前景的氨基甲酸酯清洁合成路线,高活性催化剂结合适宜的工艺流程是产业化成功的关键.%Recent progress and trends in clean synthesis of carbamates were reviewed, including a detail commentary on the catalyst systems. Ammonolysis of dimethyl carbonate (DMC) was considered to be the most promising industrial route for clean synthesis of carbamates. It was believed that developing high activity catalyst with suitable process would be the key to the industrial success.

  4. Effect of two formulations of benzimidazole carbamates on the viability of cysts of Echinococcus granulosus in vivo

    OpenAIRE

    Daniel-Mwuambete K.; Ponce-Gordo F.; Torrado J.; Torrado S.; Cuesta-Bandera C.

    2003-01-01

    Two different preparations, solution and suspension, of three benzimidazole carbamate drugs, mebendazole, albendazole and ricobendazole, were compared by analyzing their in vivo activity against Echinococcus granulosus cysts in a mouse model. Polyvinylpyrrolidone was used for the elaboration of drug solutions and these formulations manifested better results in terms of reduction of number of viable hydatid cysts in mice than the reference drug suspensions. The effect was more prominent on meb...

  5. Biodegradation of carbamate pesticides by natural river biofilms in different seasons and their effects on biofilm community structure

    International Nuclear Information System (INIS)

    This study investigated the ability of natural river biofilms from different seasons to degrade the carbamate pesticides methomyl, carbaryl and carbofuran in single and multiple pesticide systems, and the effects of these pesticides on algal and bacterial communities within biofilms. Spring biofilms had the lowest biomass of algae and bacteria but showed the highest methomyl degradation (>99%) and dissipation rates, suggesting that they might contain microorganisms with high methomyl degradation abilities. Degradation of carbofuran (54.1–59.5%) by biofilms in four seasons was similar, but low degradation of carbaryl (0–27.5%) was observed. The coexistence of other pesticides was found to cause certain effects on pesticide degradation and primarily resulted in lower diversity of diatoms and bacteria than when using a single pesticide. The tolerant diatoms and bacteria potentially having the ability to degrade test pesticides were identified. River biofilms could be suitable biomaterials or used to isolate degraders for bioremediating pesticide-contaminated water. -- Highlights: •Natural river biofilms showed high ability to degrade methomyl and carbofuran. •The presence of other pesticides caused certain effects on pesticide degradation. •Carbamate pesticides caused adverse effects on communities of diatoms and bacteria. •The tolerant diatoms and bacteria were found as potential pesticide-degraders. -- Biodegradation of carbamate pesticides by river biofilms

  6. Possible mechanisms for sensitivity to organophosphorus and carbamate insecticides in eastern screech-owls and American kestrels

    Science.gov (United States)

    Vyas, N.B.; Thiele, L.A.; Garland, S.C.

    1998-01-01

    Effects of a single dietary exposure to fenthion and carbofuran on the survival, feeding behavior and brain ChE activity of eastern screech-owls, Otus asio and American kestrels, Falco sparverius, were evaluated. Birds were exposed to fenthion (23.6189.0 ppm) or carbofuran (31.7253.6 ppm) via meatballs. Carbofuran-exposed owls ate either = 80% of the meatball whereas all kestrels ate <= 10% of the meatball before exhibiting acute signs of toxicity. Fenthion-exposed owls and kestrels displayed a wide spectrum of meatball consumption (<10100%). Significant brain ChE inhibition was observed in dead and surviving kestrels exposed to fenthion and carbofuran and dead owls exposed to fenthion (P < 0.0001). Brain ChE activity of owls exposed to carbofuran that survived was not different from that of controls (P = 0.25). Data suggest: (1) slow feeding on a carbamate-contaminated item may provide limited protection from the toxicity of the chemical at certain rates of exposure; (2) the degree of ChE inhibition at neuromuscular junctions may be critical in determining the sensitivity of a species to a carbamate insecticide; (3) sensitivity may be a function of the ChE affinity for the carbamate inhibitor; and (4) the importance of neuromuscular junction ChE depression in determining the sensitivity of an animal may be species-specific.

  7. Precipitation of calcium carbonate from a calcium acetate and ammonium carbamate batch system

    Science.gov (United States)

    Prah, J.; Maček, J.; Dražič, G.

    2011-06-01

    In this paper, we report a novel approach for preparing precipitated calcium carbonate using solutions of ammonium carbamate and calcium acetate as the sources of calcium and carbon dioxide, respectively. Two different concentrations of the starting solutions at three different temperatures (15, 25 and 50 °C) were used for the reaction. The influence of temperature and concentration on the polymorphism and the resulting morphology of calcium carbonate are discussed. The most important parameter for controlling a particular crystal structure and precipitate morphology were the concentrations of the initial solutions. When initial solutions with lower concentrations were used, the crystal form of the precipitate changed with time. Regardless the different polymorphism at different temperatures, after one day only the calcite form was detected in all samples, regardless of at which temperature the samples were prepared. At higher concentrations, pure vaterite or a mixture of vaterite and calcite were present at the beginning of the experiment. After one day, pure vaterite was found in the samples that were prepared at 15 and 25 °C. If calcium carbonate precipitated at 50 °C, the XRD results showed a mixture of calcite and vaterite regardless of the time at which the sample was taken. The morphology of calcium carbonate particles prepared at various conditions changed from calcite cubes to spherical particles of vaterite and aragonite needles. When a low starting concentration was used, the morphology at the initial stage was strongly affected by the temperature at which the experiments were conducted. However, after one day only, cubes were present in all cases at low initial concentrations. In contrast, at high concentrations spherical particles precipitated at all three temperatures at the beginning of the reaction. Spherical particles were made up from smaller particles. Over time, the size of the particles was diminishing due to their disintegration into

  8. Determination of Ethyl Carbamate in Alcoholic Beverages and Fermented Foods Sold in Korea.

    Science.gov (United States)

    Ryu, Dayeon; Choi, Bogyoung; Kim, Eunjoo; Park, Seri; Paeng, Hwijin; Kim, Cho-Il; Lee, Jee-Yeon; Yoon, Hae Jung; Koh, Eunmi

    2015-09-01

    Ethyl carbamate (EC) classified as a probable human carcinogen (Group 2A) is naturally formed in alcoholic beverages and fermented foods during fermentation process and/or during storage. The objective of this study was to analyze EC in 34 food items including 14 alcoholic beverages and 20 fermented foods sold in Korea. Each food was collected from 18 supermarkets in 9 metropolitan cities in Korea, and then made into composite. According to food composition and alcohol content, samples were divided into four matrices such as apple juice, milk, Soju (liquor containing about 20% alcohol), and rice porridge. The maximum EC value of 151.06 µg/kg was found in Maesilju (liquor made from Maesil and Soju). Whisky and Bokbunjaju (Korean black raspberry wine) contained 9.90 µg/kg and 6.30 µg/kg, respectively. EC was not detected in other alcoholic beverages. Of 20 fermented foods, Japanese-style soy sauce had highest level of 15.59 µg/kg and traditional one contained 4.18 µg/kg. Soybean paste had 1.18 µg/kg, however, EC was not found in other fermented foods. PMID:26483888

  9. Comparative voltammetric study and determination of carbamate pesticide residues in soil at carbon nanotubes paste electrodes

    Directory of Open Access Journals (Sweden)

    THOMMANDRU RAVEENDRANATH BAB

    2014-02-01

    Full Text Available In this investigation, the persistence of carbamate pesticides in soil samples was investigated. A simple and selective differential pulse adsorptive stripping voltammetry was selected for this investigation. Carbon nanotubes paste electrodes were used as working electrodes for differential pulse adsorptive stripping voltammetry and cyclic voltammetry. A symmetric study of the various operational parameters that affect the stripping response was carried out by differential pulse voltammetry. Peak currents were linear over the concentration range of 10-5 to 10-10 M with an accumulation potential of -0.6 V and a 70 s accumulation time with lower detection limits of 1.09 x 10-7 M, 1.07 × 10-7M, 1.09×10-7 M for chlorphropham, thiodicarb, aldicarb. The relative standard deviation (n=10 and correlation coefficient values were 1.15 %, 0.988; 1.13 %, 0.978; and 1.14 %, 0.987, respectively. Universal buffer with pH range 2.0 - 6.0 was used as sup­porting electrolyte. The solutions with uniform concentration (10-5 M were used in all deter­minations. Calculations were made by standard addition method.

  10. Surface display of recombinant Drosophila melanogaster acetylcholinesterase for detection of organic phosphorus and carbamate pesticides.

    Directory of Open Access Journals (Sweden)

    Jingquan Li

    Full Text Available Acetylcholinesterase (AChE is commonly used for the detection of organophosphate (OP and carbamate (CB insecticides. However, the cost of this commercially available enzyme is high, making high-throughput insecticide detection improbable. In this study we constructed a new AChE yeast expression system in Saccharomyces cerevisiae for the expression of a highly reactive recombinant AChE originating from Drosophila melanogaster (DmAChE. Specifically, the coding sequence of DmAChE was fused with the 3'-terminal half of an α-agglutinin anchor region, along with an antigen tag for the detection of the recombinant protein. The target sequence was cloned into the yeast expression vector pYes-DEST52, and the signal peptide sequence was replaced with a glucoamylase secretion region for induced expression. The resultant engineered vector was transformed into S. cerevisiae. DmAChE was expressed and displayed on the cell surface after galactose induction. Our results showed that the recombinant protein displayed activity comparable to the commercial enzyme. We also detected different types of OP and CB insecticides through enzyme inhibition assays, with the expressed DmAChE showing high sensitivity. These results show the construction of a new yeast expression system for DmAChE, which can subsequently be used for detecting OP and CB insecticides with reduced economic costs.

  11. Vibrational spectra and normal coordinate analysis of 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate

    Science.gov (United States)

    Muthu, S.; Renuga, S.

    2014-11-01

    In this work, the vibrational spectral analysis was carried out by using FT-Raman and FTIR spectroscopy in the range 50-4000 cm-1 and 450-4000 cm-1 respectively, for 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate (2H3MPPLC) molecule. The molecular structure, fundamental vibrational frequencies and intensities of the vibrational bands were interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) and ab initio HF methods with 6-31G(d,p) basis set. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The scaled B3LYP/6-31G(d,p) results show the best agreement with the experimental values over the other method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results confirm the occurrence of intramolecular charge-transfer (ICT) within the molecule. The dipole moment (μ), polarizability (α) and hyperpolarizability (β) of the investigated molecule has been computed using B3LYP/6-31G(d,p) method. Mulliken population analysis on atomic charges was also calculated. Besides, frontier molecular orbitals, molecular electrostatic potential (MEP) and thermodynamic properties were performed.

  12. Identification of Novel Steroidal Androgen Receptor Degrading Agents Inspired by Galeterone 3β-Imidazole Carbamate.

    Science.gov (United States)

    Purushottamachar, Puranik; Kwegyir-Afful, Andrew K; Martin, Marlena S; Ramamurthy, Vidya P; Ramalingam, Senthilmurugan; Njar, Vincent C O

    2016-07-14

    Degradation of all forms of androgen receptors (ARs) is emerging as an advantageous therapeutic paradigm for the effective treatment of prostate cancer. In continuation of our program to identify and develop improved efficacious novel small-molecule agents designed to disrupt AR signaling through enhanced AR degradation, we have designed, synthesized, and evaluated novel C-3 modified analogues of our phase 3 clinical agent, galeterone (5). Concerns of potential in vivo stability of our recently discovered more efficacious galeterone 3β-imidazole carbamate (6) led to the design and synthesis of new steroidal compounds. Two of the 11 compounds, 3β-pyridyl ether (8) and 3β-imidazole (17) with antiproliferative GI50 values of 3.24 and 2.54 μM against CWR22Rv1 prostate cancer cell, are 2.75- and 3.5-fold superior to 5. In addition, compounds 8 and 17 possess improved (∼4-fold) AR-V7 degrading activities. Importantly, these two compounds are expected to be metabolically stable, making them suitable for further development as new therapeutics against all forms of prostate cancer. PMID:27437082

  13. Immobilization of acetylcholinesterase via biocompatible interface of silk fibroin for detection of organophosphate and carbamate pesticides

    Science.gov (United States)

    Xue, Rui; Kang, Tian-Fang; Lu, Li-Ping; Cheng, Shui-Yuan

    2012-06-01

    An amperometric biosensor for the detection of organophosphate and carbamate pesticides was developed based on the immobilization of acetylcholinesterase (AChE) on regenerated silk fibroin (SF) matrix by non-covalent adsorption. SF and AChE were coated sequentially on the surface of the glassy carbon electrode (GCE) which was modified with multiwall carbon nanotube (MWNTs). The obtained biosensor was denoted as AChE-SF/MWNTs/GCE. The atomic force microscopy images showed that the SF matrix provided a more homogeneous interface for the AChE immobilization. The aggregation of immobilizing AChE was therefore avoided. The cyclic voltammogram of thiocholine at this biosensor exhibited a well defined oxidation peak at 0.667 V (vs. SCE). The inhibition rate of methyl parathion to the immobilized AChE was proportional to the logarithm of the concentration of methyl parathion over the range of the concentration of methyl parathion from 3.5 × 10-6 to 2.0 × 10-3 M with a detection limit of 5.0 × 10-7 M. Similarly, the linearly response range of carbaryl was from 1.0 × 10-7 to 3.0 × 10-5 M with a detection limit of 6.0 × 10-8 M. The experimental results indicate that AChE not only can be immobilized steadily on the SF matrix, but also the bioactivity of immobilizing AChE can be preserved effectively.

  14. Validation of analytical methods for ethyl carbamate in nine food matrices.

    Science.gov (United States)

    Ryu, Dayeon; Choi, Bogyoung; Kim, Nayoung; Koh, Eunmi

    2016-11-15

    Ethyl carbamate (EC) is formed through a reaction between ethanol and either cyanate or N-carbamyl compounds. This study aimed to develop and validate analytical methods for EC determination in nine food matrices: apple juice, soju, milk, corn oil, rice porridge, peanut butter, beef, flat fish, and sea mustard. Differences from AOAC procedure were use of d5-EC as internal standard, dilution of alcohol content, removal of lipophilic compounds by hexane, and removal of hydrophilic polysaccharides by gel-forming. Standard curves had a good linearity (R(2)>0.997) in all matrices tested. LOD and LOQ were in the range of 0.69-6.08μg/kg and 2.10-18.43μg/kg, respectively. Recovery rates ranged from 80.75 to 121.82% for intra-day and ranged from 78.84 to 116.98% for inter-day. The relative standard deviations (RSDs) were below 14%. These results indicate that the established methods can be applied to determine EC in a variety of foods. PMID:27283695

  15. Tandem Mass Spectrometry Measurement of the Collision Products of Carbamate Anions Derived from CO2 Capture Sorbents: Paving the Way for Accurate Quantitation

    Science.gov (United States)

    Jackson, Phil; Fisher, Keith J.; Attalla, Moetaz Ibrahim

    2011-08-01

    The reaction between CO2 and aqueous amines to produce a charged carbamate product plays a crucial role in post-combustion capture chemistry when primary and secondary amines are used. In this paper, we report the low energy negative-ion CID results for several anionic carbamates derived from primary and secondary amines commonly used as post-combustion capture solvents. The study was performed using the modern equivalent of a triple quadrupole instrument equipped with a T-wave collision cell. Deuterium labeling of 2-aminoethanol (1,1,2,2,-d4-2-aminoethanol) and computations at the M06-2X/6-311++G(d,p) level were used to confirm the identity of the fragmentation products for 2-hydroxyethylcarbamate (derived from 2-aminoethanol), in particular the ions CN-, NCO- and facile neutral losses of CO2 and water; there is precedent for the latter in condensed phase isocyanate chemistry. The fragmentations of 2-hydroxyethylcarbamate were generalized for carbamate anions derived from other capture amines, including ethylenediamine, diethanolamine, and piperazine. We also report unequivocal evidence for the existence of carbamate anions derived from sterically hindered amines ( Tris(2-hydroxymethyl)aminomethane and 2-methyl-2-aminopropanol). For the suite of carbamates investigated, diagnostic losses include the decarboxylation product (-CO2, 44 mass units), loss of 46 mass units and the fragments NCO- ( m/z 42) and CN- ( m/z 26). We also report low energy CID results for the dicarbamate dianion (-O2CNHC2H4NHCO{2/-}) commonly encountered in CO2 capture solution utilizing ethylenediamine. Finally, we demonstrate a promising ion chromatography-MS based procedure for the separation and quantitation of aqueous anionic carbamates, which is based on the reported CID findings. The availability of accurate quantitation methods for ionic CO2 capture products could lead to dynamic operational tuning of CO2 capture-plants and, thus, cost-savings via real-time manipulation of solvent

  16. Ethyl carbamate in cachaça (Brazilian sugarcane spirit): Extended survey confirms simple mitigation approaches in pot still distillation.

    Science.gov (United States)

    Nóbrega, Ian C C; Pereira, José A P; Paiva, José E; Lachenmeier, Dirk W

    2011-08-01

    In 2009, we reported an association between low levels of ethyl carbamate (EC) in pot still cachaças from Paraíba State, Brazil, and distillation in copper pot stills equipped with cooled columns. To strengthen these observations, we extended our study to Pernambuco State and assessed 13 pot still and 20 column still cachaça brands. An EC range from distillation apparatus. Maximising distillation reflux ratios in the ascending parts and minimising exposure to copper in the descending parts (through the use of stainless steel) can reduce EC, and also avoid copper contamination. PMID:25214121

  17. tert-Butyl N-[2-(N-isobutyl-4-meth-oxy-benzene-sulfonamido)-eth-yl]carbamate.

    Science.gov (United States)

    Bai, Xiao-Guang; Wang, Ju-Xian

    2014-06-01

    The title compound, C18H30N2O5S, was synthesized by the reaction of tert-butyl 2-(iso-butyl-amino)-ethyl-carbamate with p-meth-oxy-phenyl-sulfonyl chloride. In the mol-ecule, two intra-molecular C-H⋯O hydrogen bonds are observed. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds involving the imino group N atom and the ester group O atom into chains running parallel to the b axis. The chains are further connected by C-H⋯O hydrogen bonds, forming layers parallel to the bc plane. PMID:24940254

  18. Synthesis and antimicrobial activities of new oxime carbamates of 3-aryl-2-thioquinazolin-4(3H)-one

    Indian Academy of Sciences (India)

    Suresh S Patil; Swati D Jadhav; M B Deshmukh

    2012-09-01

    S-alkylation of 3-aryl-2-thioquinazolin-4(3H)-one (1) with chloroacetone gave 2-(propanonyl thio)-3-arylquinazol-4(3H)ones (2). Further, the treatment of compound (2) with hydroxylamine hydrochloride gave the corresponding oximes (3) which on reaction with phenyl isocyanate in THF yielded corresponding oxime carbamates 4. The synthesized compounds have been confirmed using IR and 1H NMR, mass spectral data together with elemental analysis. All newly synthesized compounds have been tested for their antibacterial and antifungal activities.

  19. Onsager heat of transport of carbon dioxide at the surface of aqueous ammonia: The remarkable effect of carbamate formation

    Science.gov (United States)

    Packwood, Daniel M.; Phillips, Leon F.

    2010-11-01

    The Onsager heat of transport Q∗ has been measured for CO 2 at the surface of aqueous ammonia. The heat of transport incorporates the enthalpy of reaction of gaseous CO 2 with ammonia, adsorbed on the liquid surface, to form adsorbed ammonium carbamate, with the result that -Q∗ has the unusually large value of 180 kJ mol -1. Measurement of Q∗ for transfer of a reactive species through a surfactant monolayer is proposed as a new method of studying reactions at liquid and quasi-liquid surfaces.

  20. 酒中氨基甲酸乙酯的研究%Research Advancement of Ethyl Carbamate in Liquor

    Institute of Scientific and Technical Information of China (English)

    张瑞雨; 梁孟军; 李旭

    2014-01-01

    The mechanism,jeopardy,analysis method of ethyl carbamate(EC) was summarized as a carcinogen for public health.The limitation standard of EC was proposed to be established.%本文对酒中氨基甲酸乙酯的形成机制、危害、检测方法进行了综述,引起社会对这种致癌物质的认识和关注,倡导建立氨基甲酸乙酯的限量标准。

  1. tert-Butyl N-[6-(N,N-dipropylcarbamoyl-1,3-benzothiazol-2-yl]carbamate

    Directory of Open Access Journals (Sweden)

    Xin Fang

    2010-05-01

    Full Text Available The title compound C19H27N3O3S, crystallizes with two unique molecules in the asymmetric unit. The benzene ring of each benzothiazole unit carries a dipropylcarbamoyl substituent in the 6-position and a tert-butyl carbamate unit on each thiazole ring. In the crystal structure, intermolecular N—H...N and weak C—H...O hydrogen bonds form centrosymmetric dimers. Additional C—H...O contacts construct a three-dimensional network. A very weak C—H...π contact is also present.

  2. Immobilization of acetylcholinesterase via biocompatible interface of silk fibroin for detection of organophosphate and carbamate pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Xue Rui [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Kang Tianfang, E-mail: kangtf@yahoo.cn [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Lu Liping; Cheng Shuiyuan [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

    2012-06-01

    An amperometric biosensor for the detection of organophosphate and carbamate pesticides was developed based on the immobilization of acetylcholinesterase (AChE) on regenerated silk fibroin (SF) matrix by non-covalent adsorption. SF and AChE were coated sequentially on the surface of the glassy carbon electrode (GCE) which was modified with multiwall carbon nanotube (MWNTs). The obtained biosensor was denoted as AChE-SF/MWNTs/GCE. The atomic force microscopy images showed that the SF matrix provided a more homogeneous interface for the AChE immobilization. The aggregation of immobilizing AChE was therefore avoided. The cyclic voltammogram of thiocholine at this biosensor exhibited a well defined oxidation peak at 0.667 V (vs. SCE). The inhibition rate of methyl parathion to the immobilized AChE was proportional to the logarithm of the concentration of methyl parathion over the range of the concentration of methyl parathion from 3.5 Multiplication-Sign 10{sup -6} to 2.0 Multiplication-Sign 10{sup -3} M with a detection limit of 5.0 Multiplication-Sign 10{sup -7} M. Similarly, the linearly response range of carbaryl was from 1.0 Multiplication-Sign 10{sup -7} to 3.0 Multiplication-Sign 10{sup -5} M with a detection limit of 6.0 Multiplication-Sign 10{sup -8} M. The experimental results indicate that AChE not only can be immobilized steadily on the SF matrix, but also the bioactivity of immobilizing AChE can be preserved effectively.

  3. An evaluation of ethyl-6-ethoxybenzothiazole-2-carbamate (Sch 18099) for anthelmintic activity in domestic animals.

    Science.gov (United States)

    Panitz, E

    1977-03-01

    Ethyl-6-ethoxybenzothiazole-2-carbamate (Sch 18099) was evaluated for efficacy against natural helminth infections in ponies, pigs, lambs and chickens. Sixteen critical trials were conducted in ponies at dosages of 15 to 150 mg/kg. At 15 mg/kg, efficacy against adult and larval Oxyuris equi was 100% and 91% and against small strongyles it was 98%. Efficacy levels were 95% against Strongylus vulgaris and S. edentatus at the 20 mg/kg dosage. In two trials at 100 mg/kg efficacy against Parascaris equorum was 77%. No efficacy was observed against Gastrophilus spp. or Anoplocephala spp. In swine single oral doses of 10 to 100 mg/kg were not effective. 500 ppm Sch 18099 in the diet for seven days resulted in 100% efficacy against Ascaris suum and Trichuris suis but had no effect on Stongyloides ransomi. Efficacy at 250 ppm against A. suum was 77%. Efficacy at 200 mg/kg in lambs was greater than 90% for Haemonchus contortus, Trichostrongylus axei, Marshallagia marshalli, Bunostomum trignocephalum, Oesophagostomum columbianum, Trichuris ovis, and Chabertia spp. Efficacy was less than 80% for Trichostrongylus vitrinus, Nematodirus filicollis, Ostertagia circumcinta and Cooperia curticei. Except for O. circumcinta and C. curticei, drug efficacy was reduced for these worms in lambs treated at 100 mg/kg. Efficacies of 14.3-89% against Ascaridia galli were obtained with dietary levels of 125-1000 ppm Sch 18099 fed for 7 days. Efficacy of 100% was recorded against Heterakis gallinarum at the 1000 ppm dietary drug level. PMID:864223

  4. Vibrational spectra study of phosphorus dendrimer containing azobenzene, ammonium and carbamate groups

    Science.gov (United States)

    Furer, V. L.; Vandyukov, A. E.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2013-06-01

    The FTIR and FT Raman spectra of the first generation dendrimers, possessing carbamate (G1) or ammonium (G2) terminal groups were studied. The structural optimization and normal mode analysis were performed for dendrimers on the basis of the density functional theory (DFT). These calculations of G2 gave the frequencies of vibrations, infrared intensities and Raman scattering activities for the E- and Z-forms of azobenzene unit. The energy difference between the E- and Z-forms of G2 is 27.36 kcal/mol. The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. It was found that dendrimers molecules have a concave lens structure with planar -O-C6H4-CHdbnd N-N(CH3)Pdbnd S, and -O-C6H4-Ndbnd N-C6H4-CHdbnd N-NH-Cdbnd O-CH2-N fragments and slightly non-planar cyclotriphosphazene core. The experimental IR and Raman spectra of dendrimers G1 and G2 were interpreted by means of potential energy distributions. Relying on DFT calculations a complete vibrational assignment is proposed. The strong band 1605 cm-1 in the IR spectra show marked changes of the optical density in dependence of substituents in the aromatic ring. The differences in the IR and Raman spectra of G2 for the E- and Z-forms of azobenzene units were cleared up. During structural isomerization of azobenzene units, redistribution of band intensities appears to a much higher extent than frequency shifts.

  5. Effects of organophosphate,carbamate and pyrethroid insecticides and their mixtures on neuromuscular junction transmission

    Institute of Scientific and Technical Information of China (English)

    HeFS; XiaoC

    2002-01-01

    To investigate the effects of organophosphorus (OP),carbamate (Carb),pyrehroid (Pyr) insecticides and their mixtures on neuromuscular junction transmission (NMJT),dimethoate(D) and phoxim(P),methomyl(M),and fenvalerate(F) were selected.Rats were intraperitoneally intoxicated by D,P,M,F,D+M,D+F,P+M,or P+F with the dosage of each LD50 respectively.The function of the NMJT was assessed with the mean consecutive differences (MCD) of the latencies of single fiber action potentials detected by stimulation single fiber electromyography(SSFEMG) at the stimulus frequency of 20 Hz.The SSFEMG was also applied to detect the function of NMJT in 40 patients with OPs and their mixtures poisoning in this study.The results showed that (1)the myasthenia occurred only in rats with OPs and their mixtures poisoning,but not in F,M intoxicated rats.The increase of MCD shown by SSFEMG and induced by OP and their mixtures indicating a post-synaptic block was well correlated with the occurrence of myasthenia both in rats and patients(P<0.001);(2)the increase of MCD in rats of OP poisoning was significant in comparison with the control and F,M intoxicated rats;but was not significantly different from those in rats intoxicated by OP mixtures;(3)the MCDs were significantly increased in IMS patients of both acute OP poisoning and OP mixtures poisoning,but showing no significant difference between the two groups of patients.It is concluded that OP is the only responsible agent for the dysfunction of neuromuscular transmission induced by single OP and OP mixture insecticides which could be sensitively detected by SSFEMG.

  6. Detection of Methomyl, a Carbamate Insecticide, in Food Matrices Using Terahertz Time-Domain Spectroscopy

    Science.gov (United States)

    Baek, Seung Hyun; Kang, Ju Hee; Hwang, Yeun Hee; Ok, Kang Min; Kwak, Kyungwon; Chun, Hyang Sook

    2016-05-01

    The aim of this study was to investigate the feasibility of detecting methomyl, a carbamate insecticide, in food matrices (wheat and rice flours) using terahertz time-domain spectroscopy (THz-TDS). In the frequency range 0.1-3 THz, the characteristic THz absorption peaks of methomyl at room temperature were detected at 1 (33.4 cm-1), 1.64 (54.7 cm-1), and 1.89 (63.0 cm-1) THz. For detailed spectral analysis, the vibrational frequency and intensity of methomyl were calculated using solid-state density functional theory to mimic molecular interactions in the solid state. Qualitatively, the simulated spectrum was in good agreement with the experimental spectrum. Analysis of the individual absorption modes revealed that all of the features in the THz spectrum of methomyl were mainly generated from intermolecular vibrations. The peak appearing at 1 THz (33.4 cm-1) was then selected and tested for its suitability as a fingerprint for detecting methomyl in food matrices. Its absorbance was dose-dependently distinguishable from that of wheat and rice flours. The calibration curve of methomyl had a regression coefficient of >0.974 and a detection limit of <3.74 %. Accuracy and precision expressed as recovery and relative standard deviation in interday repeatability were in the ranges 78.0-96.5 and 2.83-4.98 %, respectively. Our results suggest that THz-TDS can be used for the rapid detection of methomyl in foods, but its sensitivity needs to be improved.

  7. High lethality and minimal variation after acute self-poisoning with carbamate insecticides in Sri Lanka – implications for global suicide prevention

    Science.gov (United States)

    Lamb, Thomas; Selvarajah, Liza R.; Mohamed, Fahim; Jayamanne, Shaluka; Gawarammana, Indika; Mostafa, Ahmed; Buckley, Nicholas A.; Roberts, Michael S.; Eddleston, Michael

    2016-01-01

    Abstract Background: Highly hazardous organophosphorus (OP) insecticides are responsible for most pesticide poisoning deaths. As they are removed from agricultural practice, they are often replaced by carbamate insecticides of perceived lower toxicity. However, relatively little is known about poisoning with these insecticides. Methods: We prospectively studied 1288 patients self-poisoned with carbamate insecticides admitted to six Sri Lankan hospitals. Clinical outcomes were recorded for each patient and plasma carbamate concentration measured in a sample to confirm the carbamate ingested. Findings: Patients had ingested 3% carbofuran powder (719), carbosulfan EC25 liquid (25% w/v, 389), or fenobucarb EC50 liquid (50% w/v, 127) formulations, carbamate insecticides of WHO Toxicity Classes Ib, II, and II, respectively. Intubation and ventilation was required for 183 (14.2%) patients while 71 (5.5%) died. Compared with carbofuran, poisoning with carbosulfan or fenobucarb was associated with significantly higher risk of death [carbofuran 2.2%; carbosulfan 11.1%, OR 5.5 (95% CI 3.0–9.8); fenobucarb 6.3%, OR 3.0 (1.2–7.1)] and intubation [carbofuran 6.1%; carbosulfan 27.0%, OR 5.7 (3.9–8.3); fenobucarb 18.9%, OR 3.6 (2.1–6.1)]. The clinical presentation and cause of death did not differ markedly between carbamates. Median time to death was similar: carbofuran 42.3 h (IQR 5.5–67.3), carbosulfan 21.3 h (11.5–71.3), and fenobucarb 25.3 h (17.3–72.1) (p = 0.99); no patients showed delayed onset of toxicity akin to the intermediate syndrome seen after OP insecticide poisoning. For survivors, median duration of intubation was 67.8 h (IQR 27.5–118.8) with no difference in duration between carbamates. Reduced GCS at presentation was associated with worse outcome although some patients with carbosulfan died after presentation with normal GCS. Conclusions: We did not find carbamate insecticide self-poisoning to vary markedly according to the carbamate

  8. Organophosphate and carbamate insecticides in agricultural waters and cholinesterase (ChE) inhibition in common carp (Cyprinus carpio)

    Science.gov (United States)

    Gruber, S.J.; Munn, M.D.

    1998-01-01

    Cholinesterase (ChE) activity was used as a biomarker for assessing exposure of common carp (Cyprinus carpio) to organophosphate and carbamate insecticides from irrigated agricultural waters. Carp were collected from a lake (Royal Lake) that receives most of its water from irrigation return flows and from a reference lake (Billy Clapp Lake) outside of the irrigation system. Results indicated that the mean whole-brain ChE activity of carp from Royal Lake (3.47 μmol/min/g tissue) was 34.2% less than that of carp from Billy Clapp Lake (5.27 μmol/min/g tissue) (p = 0.003). The depressed ChE activity in brain tissue of Royal Lake carp was in response to ChE-inhibiting insecticides detected in water samples in the weeks prior to tissue sampling; the most frequently detected insecticides included chlorpyrifos, azinphos-methyl, carbaryl, and ethoprop. Neither sex nor size appears to be a covariable in the analysis; ChE activity was not correlated with fish length or weight in either lake and there was no significant difference in ChE activity between the two sexes within each lake. Although organophosphate and carbamate insecticides can break down rapidly in the environment, this study suggests that in agricultural regions where insecticides are applied for extended periods of the year, nontarget aquatic biota may be exposed to high levels of ChE-inhibiting insecticides for a period of several months.

  9. Novel 2-aminopyrimidine carbamates as potent and orally active inhibitors of Lck: synthesis, SAR, and in vivo antiinflammatory activity.

    Science.gov (United States)

    Martin, Matthew W; Newcomb, John; Nunes, Joseph J; McGowan, David C; Armistead, David M; Boucher, Christina; Buchanan, John L; Buckner, William; Chai, Lilly; Elbaum, Daniel; Epstein, Linda F; Faust, Theodore; Flynn, Shaun; Gallant, Paul; Gore, Anu; Gu, Yan; Hsieh, Faye; Huang, Xin; Lee, Josie H; Metz, Daniela; Middleton, Scot; Mohn, Deanna; Morgenstern, Kurt; Morrison, Michael J; Novak, Perry M; Oliveira-dos-Santos, Antonio; Powers, David; Rose, Paul; Schneider, Stephen; Sell, Stephanie; Tudor, Yanyan; Turci, Susan M; Welcher, Andrew A; White, Ryan D; Zack, Debra; Zhao, Huilin; Zhu, Li; Zhu, Xiaotian; Ghiron, Chiara; Amouzegh, Patricia; Ermann, Monika; Jenkins, James; Johnston, David; Napier, Spencer; Power, Eoin

    2006-08-10

    The lymphocyte-specific kinase (Lck) is a cytoplasmic tyrosine kinase of the Src family expressed in T cells and NK cells. Genetic evidence in both mice and humans demonstrates that Lck kinase activity is critical for signaling mediated by the T cell receptor (TCR), which leads to normal T cell development and activation. A small molecule inhibitor of Lck is expected to be useful in the treatment of T cell-mediated autoimmune and inflammatory disorders and/or organ transplant rejection. In this paper, we describe the synthesis, structure-activity relationships, and pharmacological characterization of 2-aminopyrimidine carbamates, a new class of compounds with potent and selective inhibition of Lck. The most promising compound of this series, 2,6-dimethylphenyl 2-((3,5-bis(methyloxy)-4-((3-(4-methyl-1-piperazinyl)propyl)oxy)phenyl)amino)-4-pyrimidinyl(2,4-bis(methyloxy)phenyl)carbamate (43) exhibits good activity when evaluated in in vitro assays and in an in vivo model of T cell activation. PMID:16884310

  10. Determination of Carbamate and Organophosphorus Pesticides in Vegetable Samples and the Efficiency of Gamma-Radiation in Their Removal

    Directory of Open Access Journals (Sweden)

    Muhammed Alamgir Zaman Chowdhury

    2014-01-01

    Full Text Available In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena (n=16, purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC, and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50% of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl were detected in eggplant samples; the highest carbofuran level detected was 1.86 mg/kg, while phenthoate was detected at 0.311 mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40–48%, 35–43%, and 30–45%, respectively, when a radiation strength of 0.5 kGy was utilized. However, when the radiation dose was increased to 1.0 kGy, the levels of the pesticides were reduced to 85–90%, 80–91%, and 90–95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0 kGy can remove 80–95% of some pesticides.

  11. Optimization and validation of liquid-liquid extraction with low temperature partitioning for determination of carbamates in water

    International Nuclear Information System (INIS)

    Using a 23 experimental design, liquid-liquid extraction with low temperature partitioning (LLE-LTP) was optimized and validated for analysis of three carbamates (aldicarb, carbofuran and carbaryl) in water samples. In this method, 2.0 mL of sample is placed in contact with 4.0 mL of acetonitrile. After agitation, the sample is placed in a freezer for 3 h for phase separation. The organic extract is analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). For validation of the technique, the following figures of merit were evaluated: accuracy, precision, detection and quantification limits, linearity, sensibility and selectivity. Extraction recovery percentages of the carbamates aldicarb, carbofuran and carbaryl were 90%, 95% and 96%, respectively. Even though extremely low volumes of sample and solvent were used, the extraction method was selective and the detection and quantification limits were between 5.0 and 10.0 μg L-1, and 17.0 and 33.0 μg L-1, respectively.

  12. Monitoring of N-methyl carbamate pesticide residues in water using hollow fibre supported liquid membrane and solid phase extraction

    Science.gov (United States)

    Msagati, Titus A. M.; Mamba, Bhekie B.

    The aim of this work was to develop a method for the determination of N-methyl carbamates in water involving hollow fibre supported liquid membrane (HFSLM) and solid phase extraction (SPE) as sample preparation methods. Four N-methyl carbamate pesticides, aldicarb, carbaryl, carbofuran and methiocarb sulfoxide, were simultaneously extracted and analysed by a liquid chromatograph with a diode array detector (LC-UV/DAD) and a liquid chromatograph coupled to a ion trap quadrupole mass spectrometer (LC-ESI-MS). The high performance liquid chromatography (HPLC) separation of carabamate extracts was performed on a C18 column with water-acetonitrile as the mobile phase. The mass spectrometry analyses were carried out in the positive mode, operating under both the selected ion monitoring (SIM) and full scan modes. The solid phase recoveries of the extracts ranged between 8% and 98%, with aldicarb having the highest recoveries, followed by carbaryl, carbofuran and methiocarb had the lowest recovery. The HFSLM recovery ranged between 8% and 58% and the order of recovery was similar to the SPE trend. Factors controlling the efficiency of the HFSLM extraction such as sample pH, stripping phase pH, enrichment time, stirring speed as well as organic solvent used for entrapment of analytes, were optimised to achieve the highest enrichment factors.

  13. Vibrational spectra study of fluorescent dendrimers built from the cyclotriphosphazene core with terminal dansyl and carbamate groups

    Science.gov (United States)

    Furer, V. L.; Vandyukova, I. I.; Vandyukov, A. E.; Fuchs, S.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2011-08-01

    The FTIR and FT Raman spectra of the "Janus"-type dendrimers, possessing five carbamate groups on one side and five fluorescent dansyl derivatives on the other side, with amide G1 and hydrazone G2 central linkages were studied. These surface-block dendrimers are obtained by the coupling of two different dendrons. The FTIR and FT-Raman spectra of the zero generation dendrons, built from the hexafunctional cyclotriphosphazene core, with five dansyl terminal groups and one carbamate G0 v and one oxybenzaldehyde function G0v have been recorded. The structural optimization and normal mode analysis were performed for dendron G0v on the basis of the density functional theory (DFT). The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. It was found that dendron molecule G0v has a concave lens structure with planar -O-C6H4-CHdbnd O fragments and slightly non-planar cyclotriphosphazene core. The experimental IR and Raman spectra of dendron G0v were interpreted by means of potential energy distributions. Relying on DFT calculations a complete vibrational assignment is proposed. The strong band 1597 cm -1 show marked changes of the optical density in dependence of substituents in the aromatic ring. The frequencies of ν(N-H) bands in the IR spectra reveal the presence of the different types of H-bonds in the dendrimers.

  14. Catalytic aziridination of electron-deficient olefins with an N-chloro-N-sodio carbamate and application of this novel method to asymmetric synthesis.

    Science.gov (United States)

    Minakata, Satoshi; Murakami, Yuta; Tsuruoka, Ryoji; Kitanaka, Shinsuke; Komatsu, Mitsuo

    2008-12-21

    A new method for the aziridination of electron-deficient olefins using an N-chloro-N-sodio carbamate is described; the reaction was promoted by phase-transfer catalysis (solid-liquid) and afforded aziridines from alpha,beta-unsaturated ketones, esters, sulfones and amides. PMID:19048156

  15. Is the carbamate juvenoid W-328 an insect growth regulator for the cockroach .I.Blaberus craniifer./I. Br. (Insecta, Dictyoptera)?

    Czech Academy of Sciences Publication Activity Database

    Goudey-Perriere, F.; Lemonnier, F.; Perriere, C.; Dahmani, F. Z.; Wimmer, Zdeněk

    2003-01-01

    Roč. 75, - (2003), s. 47-59. ISSN 0048-3575 Institutional research plan: CEZ:AV0Z4055905 Keywords : Blaberus craniifer * Blattella germanica * carbamate juvenoids Subject RIV: CC - Organic Chemistry Impact factor: 0.768, year: 2003

  16. Development of a strategy for the asymmetric synthesis of polycyclic polyprenylated acylphloroglucinols via N-amino cyclic carbamate hydrazones: application to the total synthesis of (+)-clusianone.

    Science.gov (United States)

    Garnsey, Michelle R; Lim, Daniel; Yost, Julianne M; Coltart, Don M

    2010-11-19

    A broadly applicable asymmetric synthetic strategy utilizing N-amino cyclic carbamate alkylation that provides access to the various stereochemical permutations of a common structural motif found in many polycyclic polyprenylated acylphloroglucinols is described. The utility of this methodology is demonstrated through the first asymmetric total synthesis of the antiviral agent (+)-clusianone. PMID:20977254

  17. A Novel Synthesis of N-Methyl-N-aryl Carbamates from Aromatic Amines and Dimethyl Carbonate Catalyzed by K2CO3/Bu4NBr

    Institute of Scientific and Technical Information of China (English)

    Zhen Lu SHEN; Xuan Zhen JIANG

    2004-01-01

    A facile synthesis of N-methyl-N-aryl carbamates from aromatic amines and dimethyl carbonate (DMC) has been achieved with high yields in the presence of potassium carbonate (K2CO3) and tetrabutylammonium bromide (Bu4NBr) under solvent-free conditions.

  18. Ferric chloride-catalyzed reaction of [60]fullerene with tert-butyl N-substituted carbamates: synthesis of oxazolidino[4,5:1,2][60]fullerenes.

    Science.gov (United States)

    You, Xun; Wang, Guan-Wu

    2014-01-01

    The rare oxazolidinofullerenes have been prepared by the ferric chloride-catalyzed reaction of [60]fullerene with various tert-butyl N-substituted carbamates via t-Bu-O bond cleavage and heteroannulation under mild conditions. A possible mechanism for the formation of oxazolidinofullerenes is proposed. PMID:24328055

  19. Quantum Chemical Studies on Solvents for Post-Combustion Carbon Dioxide Capture: Calculation of pKa and Carbamate Stability of Disubtituted Piperazines

    NARCIS (Netherlands)

    Gangarapu, S.; Wierda, G.J.; Marcelis, A.T.M.; Zuilhof, H.

    2014-01-01

    Piperazine is a widely studied solvent for post-combustion carbon dioxide capture. To investigate the possibilities of further improving this process, the electronic and steric effects of CH3, CH2F, CH2OH, CH2NH2, COCH3, and CN groups of 2,5-disubstituted piperazines on the pKa and carbamate stabili

  20. A Mechanism-based 3D-QSAR Approach for Classification and Prediction of Acetylcholinesterase Inhibitory Potency of Organophosphate and Carbamate Analogs

    Science.gov (United States)

    Organophosphate (OP) and carbamate esters can inhibit acetylcholinesterase (AChE) by binding covalently to a serine residue in the enzyme active site, and their inhibitory potency depends largely on affinity for the enzyme and the reactivity of the ester. Despite this understandi...

  1. ORALLY ACTIVE CARBAMATE PRODRUGS OF THE SELECTIVE DOPAMINE AGONIST N-0437 - INVIVO ACTIVITIES IN THE 6-OHDA TURNING MODEL AND INVITRO ACTIVITIES

    NARCIS (Netherlands)

    DENDAAS, [No Value; DEBOER, P; TEPPER, PG; ROLLEMA, H; HORN, AS

    1991-01-01

    The in-vivo activities of eight carbamate prodrugs of the D2-agonist N-0437 were determined by examining the effects of the prodrugs, after their oral administration in rats with unilateral 6-OHDA lesions of the striatum. The resulting contralateral turning was used as an index of the activity of th

  2. Evidence of carbamate resistance in urban populations of Anopheles gambiae s.s. mosquitoes resistant to DDT and deltamethrin insecticides in Lagos, South-Western Nigeria

    Directory of Open Access Journals (Sweden)

    Oduola Adedayo O

    2012-06-01

    Full Text Available Abstract Background Resistance monitoring is essential in ensuring the success of insecticide based vector control programmes. This study was carried out to assess the susceptibility status of urban populations of Anopheles gambiae to carbamate insecticide being considered for vector control in mosquito populations previously reported to be resistant to DDT and permethrin. Methods Two – three day old adult female Anopheles mosquitoes reared from larval collections in 11 study sites from Local Government Areas of Lagos were exposed to test papers impregnated with DDT 4%, deltamethrin 0.05% and propoxur 0.1% insecticides. Additional tests were carried out to determine the susceptibility status of the Anopheles gambiae population to bendiocarb insecticide. Members of the A. gambiae complex, the molecular forms, were identified by PCR assays. The involvement of metabolic enzymes in carbamate resistance was assessed using Piperonyl butoxide (PBO synergist assays. The presence of kdr-w/e and ace-1R point mutations responsible for DDT-pyrethroid and carbamate resistance mechanisms was also investigated by PCR. Results Propoxur resistance was found in 10 out of the 11 study sites. Resistance to three classes of insecticides was observed in five urban localities. Mortality rates in mosquitoes exposed to deltamethrin and propoxur did not show any significant difference (P > 0.05 but was significantly higher (P A. gambiae s.s (M form. The kdr -w point mutation at allelic frequencies between 45%-77% was identified as one of the resistant mechanisms responsible for DDT and pyrethroid resistance. Ace-1R point mutation was absent in the carbamate resistant population. However, the possible involvement of metabolic resistance was confirmed by synergistic assays conducted. Conclusion Evidence of carbamate resistance in A. gambiae populations already harbouring resistance to DDT and permethrin is a clear indication that calls for the implementation of

  3. 氨基甲酸酯淀粉浆料的制备及上浆性能%Manufacture and Sizing Performance of Carbamate Starch Size Mixture

    Institute of Scientific and Technical Information of China (English)

    刘志军; 许冬生

    2011-01-01

    探讨氨基甲酸酯淀粉的取代度对氨基甲酸酯淀粉浆料上浆性能的影响.通过改变氧化铵对淀粉的投料比,制备了一系列具有不同变性程度的氨基甲酸酯淀粉,对不同取代度的氨基甲酸酯淀粉浆料的浆液性能及对棉纤维的黏附性能进行了测试.结果表明:当取代度不超过0.053时,随氨基甲酸酯淀粉取代度的提高,浆液黏度降低,热稳定性提高,对棉纤维的黏着力增大.指出:氨基甲酸酯变性有利于改善淀粉对纯棉经纱的上浆性能.%Effect of carbamate starch substitution degree on size mixture property was discussed. Through changing feed ratio of ammonium chloride to starch,a series of carbamate starch with different substitution degree were made. Sizing property of carbamate starch with different substitution degree and adhesion performance to cotton fiber were tested. The result shows when the substitution degree is less 0. 053 and substitution degree of carbamate starch is increasing,sizing viscosity is reduced, the thermal stability is increased, the adhesion to cotton fiber is increased. It is pointed out that sizing property of carbamate starch to pure cotton yarn can be improved.

  4. Sensitive bi-enzymatic biosensor based on polyphenoloxidases-gold nanoparticles-chitosan hybrid film-graphene doped carbon paste electrode for carbamates detection.

    Science.gov (United States)

    Oliveira, Thiago M B F; Barroso, M Fátima; Morais, Simone; Araújo, Mariana; Freire, Cristina; de Lima-Neto, Pedro; Correia, Adriana N; Oliveira, Maria B P P; Delerue-Matos, Cristina

    2014-08-01

    A bi-enzymatic biosensor (LACC-TYR-AuNPs-CS/GPE) for carbamates was prepared in a single step by electrodeposition of a hybrid film onto a graphene doped carbon paste electrode (GPE). Graphene and the gold nanoparticles (AuNPs) were morphologically characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, dynamic light scattering and laser Doppler velocimetry. The electrodeposited hybrid film was composed of laccase (LACC), tyrosinase (TYR) and AuNPs entrapped in a chitosan (CS) polymeric matrix. Experimental parameters, namely graphene redox state, AuNPs:CS ratio, enzymes concentration, pH and inhibition time were evaluated. LACC-TYR-AuNPs-CS/GPE exhibited an improved Michaelis-Menten kinetic constant (26.9±0.5M) when compared with LACC-AuNPs-CS/GPE (37.8±0.2M) and TYR-AuNPs-CS/GPE (52.3±0.4M). Using 4-aminophenol as substrate at pH5.5, the device presented wide linear ranges, low detection limits (1.68×10(-9)±1.18×10(-10)-2.15×10(-7)±3.41×10(-9)M), high accuracy, sensitivity (1.13×10(6)±8.11×10(4)-2.19×10(8)±2.51×10(7)%inhibitionM(-1)), repeatability (1.2-5.8% RSD), reproducibility (3.2-6.5% RSD) and stability (ca. twenty days) to determine carbaryl, formetanate hydrochloride, propoxur and ziram in citrus fruits based on their inhibitory capacity on the polyphenoloxidases activity. Recoveries at two fortified levels ranged from 93.8±0.3% (lemon) to 97.8±0.3% (orange). Glucose, citric acid and ascorbic acid do not interfere significantly in the electroanalysis. The proposed electroanalytical procedure can be a promising tool for food safety control. PMID:24642204

  5. Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E-1-(2-benzylidene-1-methylhydrazinyl-3-hydroxy-1-oxopropan-2-yl]carbamates

    Directory of Open Access Journals (Sweden)

    Thais C. M. Noguiera

    2015-07-01

    Full Text Available The crystal structures of three methylated hydrazine carbamate derivatives prepared by multi-step syntheses from l-serine are presented, namely benzyl N-{(E-1-[2-(4-cyanobenzylidene-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C20H20N4O4, tert-butyl N-{(E-1-[2-(4-cyanobenzylidene-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C17H22N4O4, and tert-butyl N-[(E-1-(2-benzylidene-1-methylhydrazinyl-3-hydroxy-1-oxopropan-2-yl]carbamate, C16H23N3O4. One of them shows that an unexpected racemization has occurred during the mild-condition methylation reaction. In each crystal structure, the molecules are linked into chains by O—H...O hydrogen bonds, but with significant differences between them.

  6. Chiral separation on sulfonated cellulose tris(3,5-dimethylphenyl carbamate)-coated zirconia monolith by capillary electro chromatography

    International Nuclear Information System (INIS)

    Sulfonated cellulose tris(3,5-dimethylphenyl carbamate) (SCDMPC)-coated zirconia monolith (ZM) was used as the chiral stationary phase in capillary electro chromatography for separation of enantiomers of ten chiral compounds in acetonitrile (ACN)-phosphate buffer mixtures as the eluent. Influences of the ACN content, buffer concentration and pH on chiral separation have been investigated. Separation data on SCDMPC-ZM have been compared with those on CDMPC-ZM. Resolution factors were better on SCDMPC-ZM than CDMPC-ZM while retention factors were in general shorter on the former than the latter. Best chiral resolutions on SCDMPC-ZM were obtained with the eluent of 50% ACN containing 50 mM phosphate at pH around 4

  7. Ethyl Carbamate in Alcoholic Beverages from Mexico (Tequila, Mezcal, Bacanora, Sotol and Guatemala (Cuxa: Market Survey and Risk Assessment

    Directory of Open Access Journals (Sweden)

    Jürgen Rehm

    2009-01-01

    Full Text Available Ethyl carbamate (EC is a recognized genotoxic carcinogen, with widespread occurrence in fermented foods and beverages. No data on its occurrence in alcoholic beverages from Mexico or Central America is available. Samples of agave spirits including tequila, mezcal, bacanora and sotol (n=110, and of the sugarcane spirit cuxa (n=16 were purchased in Mexico and Guatemala, respectively, and analyzed for EC. The incidence of EC contamination was higher in Mexico than in Guatemala, however, concentrations were below international guideline levels (<0.15 mg/L. Risk assessment found the Margin of Exposure (MOE in line with that of European spirits. It is therefore unlikely that EC plays a role in high rates of liver cirrhosis reported in Mexico.

  8. Effect of two formulations of benzimidazole carbamates on the viability of cysts of Echinococcus granulosus in vivo

    Directory of Open Access Journals (Sweden)

    Daniel-Mwuambete K.

    2003-12-01

    Full Text Available Two different preparations, solution and suspension, of three benzimidazole carbamate drugs, mebendazole, albendazole and ricobendazole, were compared by analyzing their in vivo activity against Echinococcus granulosus cysts in a mouse model. Polyvinylpyrrolidone was used for the elaboration of drug solutions and these formulations manifested better results in terms of reduction of number of viable hydatid cysts in mice than the reference drug suspensions. The effect was more prominent on mebendazole-treated mice, at doses of 25-50 mg/kg. There was a correlation between ED50 and pharmacokinetical parameters of AUC0∞ and Cmax , showing that a significant improvement on solubility affects the in vivo activity of these drugs.

  9. Effect of two formulations of benzimidazole carbamates on the viability of cysts of Echinococcus granulosus in vivo.

    Science.gov (United States)

    Daniel-Mwuambete, K; Ponce-Gordo, F; Torrado, J; Torrado, S; Cuesta-Bandera, C

    2003-12-01

    Two different preparations, solution and suspension, of three benzimidazole carbamate drugs, mebendazole, albendazole and ricobendazole, were compared by analyzing their in vivo activity against Echinococcus granulosus cysts in a mouse model. Polyvinylpyrrolidone was used for the elaboration of drug solutions and these formulations manifested better results in terms of reduction of number of viable hydatid cysts in mice than the reference drug suspensions. The effect was more prominent on mebendazole-treated mice, at doses of 25-50 mg/kg. There was a correlation between ED50 and pharmacokinetical parameters of AUC0-infinity and Cmax, showing that a significant improvement on solubility affects the in vivo activity of these drugs. PMID:14710635

  10. Temperature-induced uptake of CO2 and formation of carbamates in mesocaged silica modified with n-propylamines.

    Science.gov (United States)

    Bacsik, Zoltán; Atluri, Rambabu; Garcia-Bennett, Alfonso E; Hedin, Niklas

    2010-06-15

    Adsorption-mediated CO(2) separation can reduce the cost of carbon capture and storage. The reduction in cost requires adsorbents with high capacities for CO(2) sorption and high CO(2)-over-N(2) selectivity. Amine-modified sorbents are promising candidates for carbon capture. To investigate the details of CO(2) adsorption in such materials, we studied mesocaged (cubic, Pm3n symmetry) silica adsorbents with tethered propylamines using Fourier transform infrared (FTIR) spectroscopy and volumetric uptake experiments. The degree of heterogeneity in these coatings was varied by either cosynthesizing or postsynthetically introducing the propylamine modification. In situ FTIR spectroscopy revealed the presence of both physisorbed and chemisorbed CO(2) in the materials. We present direct molecular evidence for physisorption using FTIR spectroscopy in mesoporous silica sorbents modified with propylamines. Physisorption reduced the CO(2)-over-N(2) selectivity in amine-rich sorbents. Samples with homogeneous coatings showed typical CO(2) adsorption trends and large quantities of IR-observable physisorbed CO(2). The uptake of CO(2) in mesocaged materials with heterogeneous propylamine coatings was higher at high temperatures than at low temperatures. At higher temperatures and low pressures, the postsynthetically modified materials adsorbed more CO(2) than did the extracted ones, even though the surface area after modification was clearly reduced and the coverage of primary amine groups was lower. The principal mode of CO(2) uptake in postsynthetically modified mesoporous silica was chemisorption. The chemisorbed moieties were present mainly as carbamate-ammonium ion pairs, resulting from the quantitative transformation of primary amine groups during CO(2) adsorption as established by NIR spectroscopy. The heterogeneity in the coatings promoted the formation of these ion pairs. The average propylamine-propylamine distance must be small to allow the formation of carbamate

  11. Vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction for the determination of carbamates in juices by micellar electrokinetic chromatography tandem mass spectrometry.

    Science.gov (United States)

    Moreno-González, David; Huertas-Pérez, José F; García-Campaña, Ana M; Gámiz-Gracia, Laura

    2015-07-01

    A new method based on vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction has been developed for the extraction of carbamate pesticides in juice samples prior to their determination by micellar electrokinetic chromatography coupled to tandem mass spectrometry. This sample treatment allowed the satisfactory extraction and the extract clean-up of 25 carbamates from different fruit and vegetal juices (banana, tomato, and peach). In this study, the addition of ammonium perfluorooctanoate in the aqueous sample in combination with vortex agitation, provided very clean extracts with short extraction times. Under optimized conditions, recoveries of the proposed method for these pesticides from fortified juice samples ranged from 81% to 104%, with relative standard deviations lower than 15%. Limits of quantification were between 2.3µgkg(-)(1) and 4.7µgkg(-)(1), showing the high sensitivity of this fast and simple method. PMID:25882424

  12. Supercritical fluid extraction for some carbamate insecticides in potatoes samples with HPLC/flourescence determination and HPLC/mass spectrometry confirmation

    OpenAIRE

    Gilvanda Silva Nunes; Santos, Teresa Cristina R.; Damiá Barceló; Alexandre Santos Pimenta; Maria Lúcia Ribeiro

    2002-01-01

    Six supercritical fluid extraction (SFE) methods were tested, by varying the following operational parameters: CO2 pressure, time and temperature of extraction, type and proportion of static modifier, and Hydromatrix®/sample rate into cell. Firstly, insecticide carbamates were extracted from spiked potatoes samples (fortification level of 0,5 mg.Kg-1) by using SPE procedures, and then final extracts were analyzed HPLC/fluorescence. Good performance was observed with SFE methods that operated ...

  13. The carbamate kinase-like carbamoyl phosphate synthetase of the hyperthermophilic archaeon Pyrococcus furiosus, a missing link in the evolution of carbamoyl phosphate biosynthesis

    OpenAIRE

    Durbecq, Virginie; Legrain, Christianne; Roovers, Martine; Piérard, André; Glansdorff, Nicolas

    1997-01-01

    Microbial carbamoyl phosphate synthetases (CPS) use glutamine as nitrogen donor and are composed of two subunits (or domains), one exhibiting glutaminase activity, the other able to synthesize carbamoyl phosphate (CP) from bicarbonate, ATP, and ammonia. The pseudodimeric organization of this synthetase suggested that it has evolved by duplication of a smaller kinase, possibly a carbamate kinase (CK). In contrast to other prokaryotes the hyperthermophilic archaeon Pyrococcus furiosus was found...

  14. 氨基甲酸酯淀粉浆料抗老化性分析%Study on Anti-aging Property of Carbamate Starch Size Mixture

    Institute of Scientific and Technical Information of China (English)

    刘志军

    2013-01-01

    探讨氨基甲酸酯淀粉浆料的抗老化性能.通过改变尿素对玉米淀粉的投料比,制备出一系列具有不同取代度的氨基甲酸酯淀粉,测试了淀粉浆液的黏度、透明度和沉降积,研究了氨基甲酸酯化变性程度与淀粉浆液抗老化性能之间的关系.结果表明:当取代度不超过0.054时,随着氨基甲酸酯化程度的提高,浆液的冷热黏度差值变小,透明度得到明显改善,沉降积增加.指出:当取代度不超过0.054时,氨基甲酸酯淀粉随取代度的提高,浆液的老化速度降低,抗老化性能明显改善.%Anti-aging property of carbamate starch size mixture was studied. A series of carbamate starch with different substitution degrees were prepared through changing the feed ration of urea to native corn starch. The viscosity, transparency and sedimentation volume of starch sizing were measured. The relationship between modification of carbamate starch and anti-aging property of the starch sizing was investigated. The result shows when the substitution degree is less 0.054,as substitution degree of carbamate starch increases,the difference of cold and hot viscosity of starch is reduced, the transparency of the starch is improved,the sedimentation volume of the starch is increased and the anti-aging property is improved significantly.

  15. 一些N-酰基取代(硫代)氨基甲酸酯的合成%The Synthesis of Some N-Acyl Carbamates & Thionocarbamates

    Institute of Scientific and Technical Information of China (English)

    杨光; 司宗兴

    1999-01-01

      合成了9种新的N-酰基取代(硫代)氨基甲酸酯化合物,它们的结构均通过IR、1HNMR及元素分析予以确证。%  Two series of carbamates were synthesized and all compounds were confirmed by 1HNMR , IR and elementary analysis . The synthetic methods and the spectrum properties of new compounds were discussed.

  16. 氨基甲酸酯类农药的微色谱快速检测法%Rapid Determination of Carbamate Pesticides by Micro-chromatography

    Institute of Scientific and Technical Information of China (English)

    卫海燕; 邵华

    2011-01-01

    [ Objective] To rapidly detect the carbamate pesticides by preparing a new instrument of micro-column detector with capillary effect. [ Methods ] Based on the principle of thin-layer chromatography, fixing the sorbent in the thin heating wire, using microcolumn detector to prepare a new instrument of micro-column detector, the carbamate pesticides was rapidly detected and analyzed qualitatively and quantitatively. [ Results ] The method can make qualitative and quantitative analysis of carbamate pesticides, and the minimum detection limit was 50 μg. [ Conclusion ] The method is simple, efficient , reproducible, with less reagent consumption,can be used to detect bulk carbamate pesticides samples and it is a new method for rapid pesticide poisoning filtering.%目的 利用毛细管效应建立制备微色谱柱检测器以快速检测氨基甲酸酯类农药.方法 在薄层色谱原理的基础上,通过将吸着剂固定于细加热丝上,利用毛细管效应制备微色谱柱检测器,对氨基甲酸酯类农药作出快速的定性分析.结果 该方法 可以对氨基甲酸酯类农药作出快速的定性分析,且最低检出量可达到50 μg.结论 该法操作简便,高效,重现性好,且试剂用量少,是批量氨基甲酸酯类农药样品定性检测和突发农药中毒事件现场快速筛选的一种新方法 .

  17. The pH dependence of the mutagenicity of methyl benzimidazol-2-yl carbamate (MBC) towards Aspergillus nidulans (Eidam) Winter and Cladosporium cucumerinum Ellis & Arth.

    Science.gov (United States)

    Nirenberg, H I; Speakman, J B

    1981-01-01

    The ability of methyl benzimidazol-2-yl carbamate (MBC) to induce point mutations to carboxin and MBC resistance in Aspergillus nidulans (Eidam) Winter and Cladosporium cucumerinum Ellis & Arth. was dependent upon the pH value of the agar medium into which it had been incorporated. The relevance of this in relation to testing chemicals for a possible mutagenic activity with microorganisms is discussed. PMID:7010148

  18. Development of heterogenized catalyst systems for the synthesis of acrylic acid derivatives from carbon dioxide and ethylene

    OpenAIRE

    Prasetyo, Eko

    2015-01-01

    Use of CO2 as chemical feedstock represents one of the most sustainable ways for carbon recycling, generating high value products. Current industrial practices include the manufacture of urea, organic (poly)carbonates, and salicylic acid. CO2 can also be used to produce CO-rich syngas, which can be further processed to olefins, aldehydes, alcohols, or synthetic fuel via the Fischer-Tropsch process. Direct carboxylation with CO2 yielding carbonates, carbamates, carboxylates, or lactones is of ...

  19. Ionic liquid polymer functionalized carbon nanotubes-doped poly(3,4-ethylenedioxythiophene) for highly-efficient solid-phase microextraction of carbamate pesticides.

    Science.gov (United States)

    Wu, Mian; Wang, Liying; Zeng, Baizhao; Zhao, Faqiong

    2016-04-29

    A poly(3,4-ethylenedioxythiophene)-ionic liquid polymer functionalized multiwalled carbon nanotubes (PEDOT-PIL/MWCNTs) composite solid-phase microextraction (SPME) coating was fabricated by electrodeposition. After being dipped in Nafion solution, a Nafion-modified coating was obtained. The outer layer Nafion played a crucial role in enhancing the durability and stability of the coating, thus it was robust enough for replicated extraction for at least 150 times without decrease of extraction performance. The Nafion-modified coating exhibited much higher sensitivity than commercial coatings for the direct extraction of carbamate pesticides in aqueous solutions, due to its strong hydrophobic effect and π-π affinity based enrichment. When it was used for the determination of carbamate pesticides in combination with gas chromatography-flame ionization detection, good linearity (correlation coefficients higher than 0.9981), low limits of detection (15.2-27.2 ng/L) and satisfactory precision (relative standard deviation <8.2%, n=5) were achieved. The developed method was applied to the analysis of four carbamate pesticides in apple and lettuce samples, and acceptable recoveries (i.e. 87.5-106.5%) were obtained for the standard addition. PMID:27036210

  20. An evaluation of liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization for the rapid and simultaneous measurement of carbamate pesticides and organophorus pesticides

    International Nuclear Information System (INIS)

    Liquid chromatography/mass spectrometry with an atmospheric pressure chemical ionization interface (LC/APCI/MS) is evaluated for the simultaneous determination of carbamate pesticides and organophosphorus pesticides in a single chromatographic analysis. APCI mass spectra of those compounds were obtained to study their ionization characteristics. APCI provided abundant ions such as protonated molecules and characteristic fragment ions for carbamate pesticides and organophosphorus pesticides. To evaluate the feasibility of the LC/APCI/MS for a routine quantitative analysis, the linearity and repeatability of LC/APCI/MS were examined by measuring standard solution mixtures of five carbamate pesticides and four organophosphorus pesticides over the range of 1 to 100 μg/mL. The peak areas in chromatograms of characteristic ions for those compounds showed less than 3% of variation from run to tun. The standard calibration curves for the nine pesticides show good linearity in the concentration range. The detection limits of the LC/APCI/MS system for those compounds range from 0.006 to 0.2 ng

  1. DFT study of structure, IR and Raman spectra of the first generation dendron built from cyclotriphosphazene core with terminal carbamate and ester groups

    Science.gov (United States)

    Furer, V. L.; Vandyukov, A. E.; Fuchs, S.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2012-06-01

    The FTIR and FT-Raman spectra of the first generation dendron built from the cyclotriphosphazene core, five arms sbnd Osbnd C6H4sbnd CHdbnd Nsbnd N(CH3)sbnd P(S)rbond2 with ten carbamate terminal groups and one ester function Gv1 have been recorded. The IR and Raman spectra of the zero generation dendron Gv0 and first generation dendrimer G1 with the same core and terminal groups were also examined. The structural optimization and normal mode analysis were performed for dendron Gv1 on the basis of the density functional theory (DFT). The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. It was found that Gv1 has a concave lens structure with planar sbnd Osbnd C6H4sbnd CHdbnd Nsbnd N(CH3)sbnd P(S)rbond2 fragments and slightly non-planar cyclotriphosphazene core. The carbamate groups attached to different arms show significant deviations from a symmetrical arrangement relative to the local planes of repeating units. The experimental IR spectrum of Gv1 dendron was interpreted by means of potential energy distributions. The strong band 1604 cm-1 shows marked changes of the optical density in dependence of the carbamate, ester or azomethyne substituents in the aromatic ring. The frequencies of ν(Nsbnd H) and ν(Cdbnd O) bands in the IR spectra reveal the presence of the different types of H-bonds in the studied dendrimers.

  2. 氨基酯交换法合成苯氨基甲酸甲酯%Synthesis of Methyl N-phenyl Carbamate by Amino-transesterification

    Institute of Scientific and Technical Information of China (English)

    张光旭; 赵小双; 余东洋; 陈林; 陈建

    2011-01-01

    以PbO经甲醇预处理获得的甲氧基铅为催化剂,苯胺(AN)与氨基甲酸甲酯(MC)为原料酯交换合成苯氨基甲酸甲酯(MPC)。考察了甲醇用量、温度、时间、催化剂用量及原料配比等条件对合成反应的影响。结果表明,m(甲醇)/m(MC)=2、反应温度为150℃、反应时间为5 h、催化剂用量为原料总量的0.1%、m(MC)/m(AN)=2时,MPC的收率可达97.5%,选择性为97.86%。%In the presence of Pb(OCH3)2 catalyst , synthesis of methyl N-phenyl carbamate(MPC) from aniline and methyl carbamate by amino-transesterfication was discussed. The effects of methanol dosage, reaction temperature, reaction time, catalyst dosage and the mass ratios of methyl carbamate to anline on the reaction were studied, and the reaction mechanism over lead methylate catalyst was proposed. Under the optimum reaction conditions, the yield of MPC reached 97. 5% and selectivity of MPC is 97. 86%.

  3. Complex effect of thiadiazole derivatives and carbamate%噻二唑衍生物与氨基甲酸酯复合效应机理研究

    Institute of Scientific and Technical Information of China (English)

    陈化飞; 许玲玲; 刘蕊; 于宁; 宋应金

    2014-01-01

    根据二巯基苯并噻二唑独特的抗高温氧化性能和特有的有色金属腐蚀抑制性能以及二戊基氨基甲酸酯特殊的抗磨性能和特殊的过氧化物的中和性能,对它们的复合进行四球摩擦磨损试验和抗氧化试验研究,并与二烷基二硫代磷酸锌的性能进行对比研究,从中找出替代其的理论依据。%According to unique high temperature oxidation resistance and corrosion inhibition of 2 mercaptobenzothiazole thiadiazole and diamyl carbamate , and unique abrasion resistance and peroxide performance of diamyl carbamate ,the complex effects of 2 mercaptobenzothia-zole thiadiazole and diamyl carbamate were studied .The complex effects were evaluated by four-ball tester and the antioxidant test .Comparing with performance of zinc dialkyl dithio-phosphate ( ZDDP) , the theory basis of alternative was found out .

  4. Research of Phosphate-carbamate Amylose Sizing Property%磷酸-氨基甲酸酯直链淀粉浆液性能研究

    Institute of Scientific and Technical Information of China (English)

    闫怀义; 贺丽丽

    2012-01-01

    Sizing property of phosphate-carbamate amylose was discussed. Phosphate-carbamate amylose, phosphate amylose and phosphate starch were prepared. Through contrast test,proper substitution of carbamate was identified for phosphate-carbamate amylose. Gelatiniiation temperature, viscosity and viscosity thermal stability were tested and contrasted for pho9phate-carbamate amylose sizing,phosphate amylose and PVA blending sizing,phosphate amylose sizing ,phosphate starch sizing,amylose sizing.com starch sizing. The above sizings were used to size C 19.5 tex yam and T/C 13 tat yam,strength and elongation of the sized yam were tested and contrasted. The result shows that sizing properties of phosphate-carbamate amylose and phosphate amylase & PVA are basically same and better than that of the other sizing obviously, sizing demands of pure cottan yarn and polyester cotton blended yarn can be reached. It is considered that phosphaie-carbamate amylose can be textile size mixture or replace PVA.%探讨磷酸-氨基甲酸酯直链淀粉的浆液性能.制备了磷酸-氨基甲酸酯直链淀粉、磷酸酯直链淀粉、磷酸酯淀粉,并采用对比试验确定了磷酸-氨基甲酸酯直链淀粉适宜于上浆的氨基甲酸酯取代度;测定并比较了磷酸-氨基甲酸酯直链淀粉浆液、磷酸酯直链淀粉和PVA混合浆液、磷酸酯直链淀粉浆液、磷酸酯淀粉浆液、直链淀粉浆液、玉米淀粉浆液的糊化温度、黏度和黏度热稳定性;用以上各种浆液在C 19.5 tex纱和T/C13 tex纱上进行了上浆试验,并进行了强伸性测定和比较.结果表明:磷酸-氧基甲酸酯直链淀粉浆液与磷酸酯直链淀粉和PVA混合浆液的性能基本相当,明显好于其他浆液,可满足纯棉纱和涤棉纱的上浆要求.认为磷酸-氧基甲酸酯直链淀粉浆液有可能成为取代PVA的纺织浆料.

  5. Structure-based design, synthesis, molecular docking, and biological activities of 2-(3-benzoylphenyl propanoic acid derivatives as dual mechanism drugs

    Directory of Open Access Journals (Sweden)

    Musa A Ahmed

    2012-01-01

    Full Text Available Purpose: 2-(3-benzoyl phenylpropanohydroxamic acid (2 and 2-{3-[(hydroxyimino(phenylmethyl]phenyl}propanoic acid (3 were synthesized from non-steroidal anti-inflammatory drug, ketoprofen as dual-mechanism drugs. Materials and Methods: Structures of the synthesized compounds were established by IR, 1 H NMR, and mass spectroscopy. Both compounds were screened for their anti-inflammatory activity in rat paw edema model and in vitro antitumor activity against 60 human tumor cell lines. Flexible ligand docking studies were performed with different matrix metalloproteinases and cyclooxygenases to gain an insight into the structural preferences for their inhibition. Results: Compound (2 proved out to be more potent than ketoprofen in rat paw edema model. Both compounds showed moderate anticancer activity ranging from 1% to 23% inhibition of growth in 38 cell lines of 8 tumor subpanels at 10 μM concentration in a single dose experiment. Hydroxamic acid analogue was found to be more potent than ketoximic analogue in terms of its antitumor activity. Conclusion: Analysis of docking results together with experimental findings provide a good explanation for the biological activities associated with synthesized compounds which may be fruitful in designing dual-target-directed drugs that may inhibit cyclooxygenases and MMPs for the treatment of cancer.

  6. Adsorption of the enantiomers of 3-chloro-1-phenyl-propanol on silica-bonded chiral quinidine carbamate

    Energy Technology Data Exchange (ETDEWEB)

    Asnin, Leonid [University of Tennessee, Knoxville (UTK); Kaczmarski, Krzysztof [University of Tennessee and Rzeszow University of Technology, Poland; Felinger, Attila [ORNL; Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

    2005-10-01

    The interactions of 3-chloro-1-phenyl-propanol with a quinidine carbamate-bonded chiral stationary phase under NPLC conditions were studied by measuring the adsorption isotherm data of its enantiomers by frontal analysis, modeling these data with a suitable isotherm model, and comparing the experimental overloaded elution band profiles with those calculated with this isotherm and the equilibrium dispersive model of liquid chromatography. The affinity energy distribution was calculated from the adsorption isotherm data. The results show that the surface of the adsorbent is heterogeneous and exhibits a bimodal adsorption energy distribution. This fact is interpreted in terms of the presence of two different types of adsorption sites on the stationary phase, nonselective and enantioselective sites. Albeit the bi-Langmuir isotherm model successfully accounts for the single-component data corresponding to both enantiomers, the competitive bi-Langmuir isotherm model does not allow an accurate prediction of the overloaded band profiles of the racemic mixture. Thermodynamic data are drawn for explanation. Some aspects of the retention mechanism are discussed in the light of the data obtained.

  7. Changes of ethyl carbamate and its precursors in maesil (Prunus mume) extract during one-year fermentation.

    Science.gov (United States)

    Choi, Bogyoung; Koh, Eunmi

    2016-10-15

    The contents of ethyl carbamate (EC), cyanide, and ethanol were determined in maesil extracts that are liquids generated from fermentation of maesil fruit and brown sugar at 25°C or 15°C for one year. EC was detected from day 150 with a maximum value of 9.7μg/kg. The cyanide levels increased with prolonged soaking time of maesil and decreased at day 150 where EC was firstly detected, indicating that cyanide is a precursor of EC. Ethanol slowly increased at 25°C, while it fluctuated at 15°C. The contents of EC, cyanide, and ethanol were higher in the extracts fermented at 25°C compared with those at 15°C. EC contents had a higher positive correlation with cyanide contents (R=0.658) than ethanol contents (R=0.351). These results indicate that fermenting temperature gave a rise of EC precursors and consequently led to the increase of EC in the maesil extract. PMID:27173569

  8. The Stepwise Behavioral Responses: Behavioral Adjustment of the Chinese Rare Minnow (Gobiocypris rarus in the Exposure of Carbamate Pesticides

    Directory of Open Access Journals (Sweden)

    Zongming Ren

    2013-01-01

    Full Text Available In order to illustrate the behavioral regulation in environmental stress, the behavioral responses of the Chinese rare minnow (Gobiocypris rarus to arprocarb, carbofuran, and oxamyl were analyzed with an online monitoring system. The Self-Organizing Map (SOM was used to define the patterns of the behavioral data obtained from treatments at concentrations of 0.1 toxic unit (TU, 1 TU, 2 TU, 5 TU, 10 TU, and 20 TU and a control. In certain cases, differences among the carbamate pesticides (CPs tested were observed. The profiles of behavioral strength (BS in SOM varied according to the concentration used. The time of the first significant decrease of the BS varied inversely with the CP concentrations. The results suggested that the behavioral regulation in the stepwise behavioral responses (SBR was evident. The primary movement behaviors shown by the SBR model included no effect, stimulation, acclimation, adjustment (readjustment, and toxic effect, especially at the lower concentrations. However, higher stress (10 TU and 20 TU might limit the function of the behavioral adjustment produced by the intrinsic response mechanisms. It was concluded that SBR, which were affected by both the concentration and the exposure time, could be used as a suitable indicator in the ecotoxicological risk assessment of CPs.

  9. Studies on the Purification and Characterization of Soybean Esterase,and Its Sensitivity to Organophosphate and Carbamate Pesticides

    Institute of Scientific and Technical Information of China (English)

    LI Jian-ke; ZHOU Yan-li; WEN Yan-xia; WANG Jian-hua; HU Qiu-hui

    2009-01-01

    Soybean esterase,a cholinesterase-like enzyme,was purified by differential centrifugation firstly,then,ammonium sulfate precipitation,dialysis,and finally,DEAE-cellulose-32 ion-exchange chromatography after extracting it from soybean seeds with phosphate buffer(0.3 mol L-1,pH 7.0).The extract recovery rate of the purified enzyme was 8.18% and purification fold was 91.58.The soybean esterase appeared as two bands on the denaturing SDS-PAGE with molecular weights of 24 and 37.2 kDa,respectively,which proved that it is a dimer protein consisting of two subunits.The result of nondenaturing PAGE revealed that the soybean esterase is a single band with cholinesterase-like activity using α-naphthyl acetate as the substrate and fast blue B salt as coloring agent.The esterase showed very high sensitivity to 18 kinds of organophosphate pesticides and 6 kinds of carbamate pesticides with the lowest detective limits of 0.03125-0.0625 and 0.03 125-0.25 mg kg-1,respectively,and can meet the demands of MRL specified by the most countries.

  10. Mechanism and kinetic study on the gas-phase reactions of OH radical with carbamate insecticide isoprocarb

    Science.gov (United States)

    Zhang, Chenxi; Yang, Wenbo; Bai, Jing; Zhao, Yuyang; Gong, Chen; Sun, Xiaomin; Zhang, Qingzhu; Wang, Wenxing

    2012-12-01

    As one of the most important carbamate insecticides, isoprocarb [2-(1-methylethyl) phenyl methylcarbamate, MIPC] is widely used in agricultural and cotton spraying. The atmospheric chemical reaction mechanism and kinetics of MIPC with OH radical have been researched using the density functional theory in this paper. The study shows that OH radical is more easily added to the C atoms of aromatic ring than to carbon-oxygen double bond, while the H atom is abstracted more difficulty from -CONH- group and aromatic ring than from the -CH3- group and the -CH- group. At room temperature, the total rate constant of MIPC with OH radical is about 5.1 × 10-12 cm3 molecule-l s-l. OH radical addition reaction and H atom abstraction reaction are both important for the OH-initiated reaction of MIPC. The energy-rich adducts (MIPC-OH) and the MIPC's radical isomers are open-shell activated radicals and can be further oxidized in the atmosphere.

  11. Novel 1,3-diacylamidopropane-2-[bis-(2-dimethylaminoethane)] carbamate pH-sensitive lipids for cationic liposome-mediated transfection

    Science.gov (United States)

    Spelios, Michael G.

    A novel series of 1,3-diacylamidopropane-2-[bis(2-dimethylaminoethane)] carbamate analogs (1,3lb) were designed for cationic lipid-assisted transfection (lipofection). First, their physicochemical properties in self-assemblies with and without plasmid DNA (pDNA) were evaluated to examine the effects of hydrophobic tail length and degree of saturation on gene delivery and expression. Significant in vitro lipofection was induced at a nitrogen:phosphate ratio (N:P) of 4:1 by the dimyristoyl, dipalmitoyl, and dioleoyl analogs 1,3lb2, 1,3lb3, and 1,3lb5, respectively, without inclusion of neutral "lipofection enhancing" co-lipids in the cationic lipid formulations. Lipofection was reduced in the presence of co-lipids except for 1,3lb5 which maintained reporter gene expression levels at N:P 4:1 and yielded increased bioactivity at a lower NP of 2:1. Physicochemical characterization of the bioactive transfection agents (cytofectins) revealed: high hydration and in-plane elasticity of lipid monolayers by Langmuir film balance measurements; fluid lipid bilayers, with gel---liquid crystalline phase transitions below physiological temperature, by fluorescence anisotropy; lipid mixing with biomembrane-mimicking vesicles by fluorescence resonance energy transfer; efficient pDNA binding and compaction by ethidium bromide displacement; cationic liposome---nucleic acid complexes (lipoplexes) with large particle sizes (mean diameter ≥ 500 nm) and zeta potentials of positive values by dynamic light scattering and electrophoretic mobility, respectively. The results suggest that well hydrated and elastic cationic lipids forming fluid lamellar assemblies are extremely potent and minimally toxic cytofectins. Second, a comparison was made between 1,3lb2 and two derivatives, one an isomer with a shorter space between the myristoyl chains and the other the monovalent form, in an effort to delineate the biological effects of interchain distance and pH-induced polar headgroup expandability

  12. 2-Phenyl-tetrahydropyrimidine-4(1H-ones – cyclic benzaldehyde aminals as precursors for functionalised β2-amino acids

    Directory of Open Access Journals (Sweden)

    Markus Nahrwold

    2009-09-01

    Full Text Available Novel procedures have been developed to condense benzaldehyde effectively with β-amino acid amides to cyclic benzyl aminals. Double carbamate protection of the heterocycle resulted in fully protected chiral β-alanine derivatives. These serve as universal precursors for the asymmetric synthesis of functionalised β2-amino acids containing acid-labile protected side chains. Diastereoselective alkylation of the tetrahydropyrimidinone is followed by a chemoselective two step degradation of the heterocycle to release the free β2-amino acid. In the course of this study, an L-asparagine derivative was condensed with benzaldehyde and subsequently converted to orthogonally protected (R-β2-homoaspartate.

  13. Arginine Catabolism by Sourdough Lactic Acid Bacteria: Purification and Characterization of the Arginine Deiminase Pathway Enzymes from Lactobacillus sanfranciscensis CB1

    OpenAIRE

    De Angelis, Maria; Mariotti, Liberato; Rossi, Jone; Servili, Maurizio; Fox, Patrick F.; Rollán, Graciela; Gobbetti, Marco

    2002-01-01

    The cytoplasmic extracts of 70 strains of the most frequently isolated sourdough lactic acid bacteria were screened initially for arginine deiminase (ADI), ornithine transcarbamoylase (OTC), and carbamate kinase (CK) activities, which comprise the ADI (or arginine dihydrolase) pathway. Only obligately heterofermentative strains such as Lactobacillus sanfranciscensis CB1; Lactobacillus brevis AM1, AM8, and 10A; Lactobacillus hilgardii 51B; and Lactobacillus fructivorans DD3 and DA106 showed al...

  14. Research advances in formation mechanism and controlling approach of the ethyl carbamate in rice wine%黄酒中氨基甲酸乙酯形成机理及控制方法研究进展

    Institute of Scientific and Technical Information of China (English)

    白卫东; 沈棚; 钱敏

    2012-01-01

    Ethyl carbamate is one of a carcinogenic substance in rice wine. The review introduced the formation mechanism of ethyl carbamate, the influence of the process of making wine on its formation and its methods of monitoring. In addition, the research progress was introduced. It can provide some reference in controlling the content of ethyl carbamate in rice wine for enterprises.%氨基甲酸乙酯是一种存在于黄酒中的致癌物质.该文主要从氨基甲酸乙酯的形成机理,酿造工艺对其形成影响和控制方法等方面进行综述,同时对未来研究方向进行了展望.旨在为企业更好地控制黄酒中的氨基甲酸乙酯含量提供参考.

  15. A Booster Pump Added on the High-Pressure Ammonium Carbamate Pump Inlet%高压甲铵泵入口增加甲铵升压泵简介

    Institute of Scientific and Technical Information of China (English)

    张青林

    2014-01-01

    During the 30・52 CO2 stripping urea plant operation ,the outlet pressure of the high‐pressure ammonium carbamate pump is low due to the low concentration of ammonium carbamate , and the whole unit is in disorder to be shut down . After adding the booster pump on the high‐pressure ammonium carbamate pump inlet ,the normal operation is ensured ,but some new problems are not yet solved .%30・52 CO2汽提法尿素装置开车过程中,因甲铵液浓度低,高压甲铵泵出口压力低,导致合成系统紊乱而被迫停车;在高压甲铵泵入口增设一台升压泵后,确保了系统的正常运行,但也带来新问题尚待解决。

  16. Purine twisted-intercalating nucleic acids: a new class of anti-gene molecules resistant to potassium-induced aggregation.

    Science.gov (United States)

    Paramasivam, Manikandan; Cogoi, Susanna; Filichev, Vyacheslav V; Bomholt, Niels; Pedersen, Erik B; Xodo, Luigi E

    2008-06-01

    Sequence-specific targeting of genomic DNA by triplex-forming oligonucleotides (TFOs) is a promising strategy to modulate in vivo gene expression. Triplex formation involving G-rich oligonucleotides as third strand is, however, strongly inhibited by potassium-induced TFO self-association into G-quartet structures. We report here that G-rich TFOs with bulge insertions of (R)-1-O-[4-(1-pyrenylethynyl)-phenylmethyl] glycerol (called twisted intercalating nucleic acids, TINA) show a much lower tendency to aggregate in potassium than wild-type analogues do. We designed purine-motif TINA-TFOs for binding to a regulatory polypurine-polypyrimidine (pur/pyr) motif present in the promoter of the KRAS proto-oncogene. The binding of TINA-TFOs to the KRAS target has been analysed by electrophoresis mobility shift assays and DNase I footprinting experiments. We discovered that in the presence of potassium the wild-type TFOs did not bind to the KRAS target, differently from the TINA analogues, whose binding was observed up to 140 mM KCl. The designed TINA-TFOs were found to abrogate the formation of a DNA-protein complex at the pur/pyr site and to down-regulate the transcription of CAT driven by the murine KRAS promoter. Molecular modelling of the DNA/TINA-TFO triplexes are also reported. This study provides a new and promising approach to create TFOs to target in vivo the genome. PMID:18456705

  17. Exploration and Pharmacokinetic Profiling of Phenylalanine Based Carbamates as Novel Substance P 1–7 Analogues

    Science.gov (United States)

    2014-01-01

    The bioactive metabolite of Substance P, the heptapeptide SP1–7 (H-Arg-Pro-Lys-Pro-Gln-Gln-Phe-OH), has been shown to attenuate signs of hyperalgesia in diabetic mice, which indicate a possible use of compounds targeting the SP1–7 binding site as analgesics for neuropathic pain. Aiming at the development of drug-like SP1–7 peptidomimetics we have previously reported on the discovery of H-Phe-Phe-NH2 as a high affinity lead compound. Unfortunately, the pharmacophore of this compound was accompanied by a poor pharmacokinetic (PK) profile. Herein, further lead optimization of H-Phe-Phe-NH2 by substituting the N-terminal phenylalanine for a benzylcarbamate group giving a new type of SP1–7 analogues with good binding affinities is reported. Extensive in vitro as well as in vivo PK characterization is presented for this compound. Evaluation of different C-terminal functional groups, i.e., hydroxamic acid, acyl sulfonamide, acyl cyanamide, acyl hydrazine, and oxadiazole, suggested hydroxamic acid as a bioisosteric replacement for the original primary amide. PMID:25516784

  18. Exploration and pharmacokinetic profiling of phenylalanine based carbamates as novel substance p 1-7 analogues.

    Science.gov (United States)

    Fransson, Rebecca; Nordvall, Gunnar; Bylund, Johan; Carlsson-Jonsson, Anna; Kratz, Jadel M; Svensson, Richard; Artursson, Per; Hallberg, Mathias; Sandström, Anja

    2014-12-11

    The bioactive metabolite of Substance P, the heptapeptide SP1-7 (H-Arg-Pro-Lys-Pro-Gln-Gln-Phe-OH), has been shown to attenuate signs of hyperalgesia in diabetic mice, which indicate a possible use of compounds targeting the SP1-7 binding site as analgesics for neuropathic pain. Aiming at the development of drug-like SP1-7 peptidomimetics we have previously reported on the discovery of H-Phe-Phe-NH2 as a high affinity lead compound. Unfortunately, the pharmacophore of this compound was accompanied by a poor pharmacokinetic (PK) profile. Herein, further lead optimization of H-Phe-Phe-NH2 by substituting the N-terminal phenylalanine for a benzylcarbamate group giving a new type of SP1-7 analogues with good binding affinities is reported. Extensive in vitro as well as in vivo PK characterization is presented for this compound. Evaluation of different C-terminal functional groups, i.e., hydroxamic acid, acyl sulfonamide, acyl cyanamide, acyl hydrazine, and oxadiazole, suggested hydroxamic acid as a bioisosteric replacement for the original primary amide. PMID:25516784

  19. [Determination of 51 carbamate pesticide residues in vegetables by liquid chromatography-tandem mass spectrometry based on optimization of QuEChERS sample preparation method].

    Science.gov (United States)

    Wang, Lianzhu; Zhou, Yu; Huang, Xiaoyan; Wang, Ruilong; Lin, Zixu; Chen, Yong; Wang, Dengfei; Lin, Dejuan; Xu, Dunming

    2013-12-01

    The raw extracts of six vegetables (tomato, green bean, shallot, broccoli, ginger and carrot) were analyzed using gas chromatography-mass spectrometry (GC-MS) in full scan mode combined with NIST library search to confirm main matrix compounds. The effects of cleanup and adsorption mechanisms of primary secondary amine (PSA) , octadecylsilane (C18) and PSA + C18 on co-extractives were studied by the weight of evaporation residue for extracts before and after cleanup. The suitability of the two versions of QuEChERS method for sample preparation was evaluated for the extraction of 51 carbamate pesticides in the six vegetables. One of the QuEChERS methods was the original un-buffered method published in 2003, and the other was AOAC Official Method 2007.01 using acetate buffer. As a result, the best effects were obtained from using the combination of C18 and PSA for extract cleanup in vegetables. The acetate-buffered version was suitable for the determination of all pesticides except dioxacarb. Un-buffered QuEChERS method gave satisfactory results for determining dioxacarb. Based on these results, the suitable QuEChERS sample preparation method and liquid chromatography-positive electrospray ionization-tandem mass spectrometry under the optimized conditions were applied to determine the 51 carbamate pesticide residues in six vegetables. The analytes were quantified by matrix-matched standard solution. The recoveries at three levels of 10, 20 and 100 microg/kg spiked in six vegetables ranged from 58.4% to 126% with the relative standard deviations of 3.3%-26%. The limits of quantification (LOQ, S/N > or = 10) were 0.2-10 microg/kg except that the LOQs of cartap and thiofanox were 50 microg/kg. The method is highly efficient, sensitive and suitable for monitoring the 51 carbamate pesticide residues in vegetables. PMID:24669707

  20. [Xenopsylla cheopis (Siphonaptera: Xenopsyllinae), fleas in rural plague areas of high altitude Madagascar: level of sensitivity to DDT, pyrethroids and carbamates after 50 years of chemical vector control].

    Science.gov (United States)

    Ratovonjato, J; Duchemin, J B; Duplantier, J M; Chanteau, S

    2000-01-01

    The resistance of Xenopsylla cheopis from urban area to pyrethroids, to DDT, and their susceptibility to carbamate are known. We have evaluated the susceptibility of X. cheopis collected from three rural localities: Ambodisiarivo (district of Antananarivo Avaradrano), Mandoto (district of Betafo), Analaroa (district of Anjozorobe) in the province of Antananarivo and in Besoa (district of Ambalavao) in the province of Fianarantsoa. The standard WHO protocol was used and four insecticides were tested: deltamethrin 0.025%, cyfluthrin 0.15% (pyrethroids), DDT 4% (organochlorine), propoxur 1% and bendiocarb 0.1% (carbamate). X. cheopis has been shown resistance to DDT 4%, to deltamethrin 0.025% but was susceptible in the rural area around Antananarivo City. They were tolerant to deltamethrin 0.025% and cyfluthrin 0.15% but susceptible to propoxur 0.1% and bendiocarbe 1% in the districts of Betafo and Anjozorobe. In Besoa, X. cheopis was resistant to DDT 4%, tolerant to deltamethrin 0.025% and cyfluthrin 0.15% but susceptible to propoxur 0.1% and bendiocarbe 1%. These results indicate that DDT and pyrethroids can not be recommended any more for the vector control in the rural area around the capital. The use of pyrethroids in the other districts of the central highland must be joined with a X. cheopis susceptibility control. In case of resistance to pyrethroids, carbamates would be proposed to control plague vector in the rural area. The high level of resistance to DDT and pyrethroid in the rural area around the capital confirms the importance of studying the flea population in different area of Madagascar and the possibility of the gene resistance propagation. PMID:12463026

  1. Determination of Carbamate Pesticides Residues in Vegetables by High Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry%高效液相色谱-串联质谱法测定蔬菜中氨基甲酸酯类农药残留

    Institute of Scientific and Technical Information of China (English)

    周长朋; 杨丽君; 徐成钢; 时文春; 王静

    2011-01-01

    A high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method was developed for the determination of 5 carbamate pesticides, including aldicarb, aldicarbsulfoxide, aldicarbsulfone, carbofuran and 3-hydroxycarbofuran in products of vegetables. Homogenized samples were extracted with acetonitrle. The extracts were dehydrated with sodium sulphate anhydrous. The extract layer was concentrated in 40°C by vacuum rotary steam to 1. 0 mL,and dried by nitrogen flowing,then redissolved in 0. 1% formic acid issolution. Identification of 5 carbamate pesticides was achieved by electospray ionization tandem mass spectrometry in positive mode using multiple reaction monitoring (MRM) and quantification analysis was performed with matrix-matched standard calibration. The results indicated that, under the optimal conditions, the calibration curves showed good linearity for 5 carbamate pesticides over the concentration range of 5. 0 - 100 jug/kg. Detection limits were 5. 0 μg/kg. The mean recoveries varied from 61. 3% to 123% at three spiked levels of 5. 0,10 and 20 μg/kg. The RSDs were less than 15%. This method is sensitive and reproducible,and suitable for the routine determination of 5 carbamate pesticides residues in vegetables.%建立了高效液相色谱-串联质谱(HPLC-MS/MS)法同时测定蔬菜中涕灭威、涕灭威砜、涕灭威亚砜、克百威、三羟基克百威5种氨基甲酸酯类农药残留的方法.样品均质后,经乙腈提取,无水硫酸钠脱水.提取液40℃减压旋蒸浓缩至1.0mL,氮气吹干后,0.1%甲酸水溶解定容;采用高效液相色谱-串联质谱电喷雾多反应监测模式检测.实验结果表明,5种氨基甲酸酯类农药在5.0~100 μg/kg范围内线性关系良好.检出限均为5.0μg/kg.6种空白基质样品中5.0、10、20 μg/kg 3水平的加标回收率为61.30%~123%,相对标准偏差均在15%以内.该方法操作简单、灵敏度高、重现性好,可用于蔬菜中5种氨

  2. Teores de carbamato de etila em aguardentes de cana e mandioca: parte II Contents of ethyl carbamate in sugar cane and manioc spirits: part II

    Directory of Open Access Journals (Sweden)

    Luiz Gualberto de Andrade Sobrinho

    2009-01-01

    Full Text Available Herein, we report the concentration of ethyl carbamate (EC and copper in 380 samples of sugar-cane spirit and 45 samples of manioc spirit as determined by GC-MS and FAAS respectively. The cyanide content determined spectrophotometrically is reported for the manioc spirit. Sugar cane spirit produced by alembic distillation (70,0 µg L-1 shown a lower content of EC than samples produced by column distillation (270 µg L-1. No simple correlation between the content of EC and copper for sugar cane spirit as well among the concentration of EC, copper, and cyanide for manioc spirit could be observed.

  3. Teores de carbamato de etila em aguardentes de cana e mandioca: parte II Contents of ethyl carbamate in sugar cane and manioc spirits: part II

    OpenAIRE

    Luiz Gualberto de Andrade Sobrinho; Luciana Tereza Dias Cappelini; Alexandre Ataíde da Silva; Carlos Alexandre Galinaro; Silmara França Buchviser; Daniel Rodrigues Cardoso; Douglas Wagner Franco

    2009-01-01

    Herein, we report the concentration of ethyl carbamate (EC) and copper in 380 samples of sugar-cane spirit and 45 samples of manioc spirit as determined by GC-MS and FAAS respectively. The cyanide content determined spectrophotometrically is reported for the manioc spirit. Sugar cane spirit produced by alembic distillation (70,0 µg L-1) shown a lower content of EC than samples produced by column distillation (270 µg L-1). No simple correlation between the content of EC and copper for sugar ca...

  4. Hypervalent iodine(iii)-promoted N-incorporation into N-aryl vinylogous carbamates to quinoxaline diesters: access to 1,4,5,8-tetraazaphenanthrene.

    Science.gov (United States)

    Sagar, A; Vidaycharan, Shinde; Shinde, Anand H; Sharada, Duddu S

    2016-04-26

    A novel oxidative N-incorporation strategy for synthesis of quinoxaline diesters under metal-free conditions is described for the first time. The mild reaction conditions allow for this transformation via the formation of two C(sp(2))-N bonds utilizing cheaply available NaN3 as the N-atom source. N-Aryl vinylogous carbamates in this study undergo azidation at enamino C(sp(2))-H selectively. The robustness of this strategy is further demonstrated by the synthesis of a valuable 1,4,5,8-tetraazaphenanthrene derivative using a mild and convenient approach. PMID:27050385

  5. Distribution of ace-1R and resistance to carbamates and organophosphates in Anopheles gambiae s.s. populations from Côte d'Ivoire

    Directory of Open Access Journals (Sweden)

    Ahoua Alou Ludovic P

    2010-06-01

    Full Text Available Abstract Background The spread of pyrethroid resistance in Anopheles gambiae s.s. is a critical issue for malaria vector control based on the use of insecticide-treated nets. Carbamates and organophosphates insecticides are regarded as alternatives or supplements to pyrethroids used in nets treatment. It is, therefore, essential to investigate on the susceptibility of pyrethroid resistant populations of An. gambiae s.s. to these alternative products. Methods In September 2004, a cross sectional survey was conducted in six localities in Côte d'Ivoire: Toumbokro, Yamoussoukro, Toumodi in the Southern Guinea savannah, Tiassalé in semi-deciduous forest, then Nieky and Abidjan in evergreen forest area. An. gambiae populations from these localities were previously reported to be highly resistant to pyrethroids insecticides. Anopheline larvae were collected from the field and reared to adults. Resistance/susceptibility to carbamates (0.4% carbosulfan, 0.1% propoxur and organophosphates (0.4% chlorpyrifos-methyl, 1% fenitrothion was assessed using WHO bioassay test kits for adult mosquitoes. Then, PCR assays were run to determine the molecular forms (M and (S, as well as phenotypes for insensitive acetylcholinesterase (AChE1 due to G119S mutation. Results Bioassays showed carbamates (carbosulfan and propoxur resistance in all tested populations of An. gambiae s.s. In addition, two out of the six tested populations (Toumodi and Tiassalé were also resistant to organophosphates (mortality rates ranged from 29.5% to 93.3%. The M-form was predominant in tested samples (91.8%. M and S molecular forms were sympatric at two localities but no M/S hybrids were detected. The highest proportion of S-form (7.9% of An. gambiae identified was in sample from Toumbokro, in the southern Guinea savannah. The G119S mutation was found in both M and S molecular forms with frequency from 30.9 to 35.2%. Conclusion This study revealed a wide distribution of insensitive

  6. Chromogenic platform based on recombinant Drosophila melanogaster acetylcholinesterase for visible unidirectional assay of organophosphate and carbamate insecticide residues

    International Nuclear Information System (INIS)

    Highlight: ► A visible chromogenic platform for rapid analysis of OP and CM insecticide residues was developed. ► The assay has the capabilities of both qualitative measurement and quantitative analysis. ► The sensitivity, capabilities of resisting interferences and storage stability were desirable. ► Matrix effects were acceptable and detection performance was satisfactory in real application. - Abstract: In this study we propose a chromogenic platform for rapid analysis of organophosphate (OP) and carbamate (CM) insecticide residues, based on recombinant Drosophila melanogaster acetylcholinesterase (R-DmAChE) as enzyme and indoxyl acetate as substrate. The visible chromogenic strip had the advantages identical to those of commonly used lateral flow assays (LFAs) with utmost simplicity in sample loading and result observation. After optimization, depending on the color intensity (CI) values, the well-established assay has the capabilities of both qualitative measurement via naked eyes and quantitative analysis by colorimetric reader with the desirable IC50 values against the tested six insecticides (0.06 μg mL−1 of carbofuran, 0.28 μg mL−1 of methomyl, 0.03 μg mL−1 of dichlorvos, 31.6 μg mL−1 of methamidophos, 2.0 μg mL−1 of monocrotophos, 6.3 μg mL−1 of omethoate). Acceptable matrix effects and satisfactory detection performance were confirmed by in-parallel LC–MS/MS analysis in different vegetable varieties at various spiked levels of 10−3 to 101 μg g−1. Overall, the testified suitability and applicability of this novel platform meet the requirements for practical use in food safety management and environmental monitoring, especially in the developing world.

  7. Chromogenic platform based on recombinant Drosophila melanogaster acetylcholinesterase for visible unidirectional assay of organophosphate and carbamate insecticide residues

    Energy Technology Data Exchange (ETDEWEB)

    Han Zheng [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Chi Chensen [School of Life Science and Biotechnology, Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Bai Bing; Liu Gang; Rao Qinxiong [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Peng Shaojie [Institute of Shanghai Food and Drug Supervision, 615 Liuzhou Road, Shanghai 200233 (China); Liu Hong [Shanghai Municipal Center for Disease Control and Prevention, 1380 Zhongshan West Road, Shanghai 200336 (China); Zhao Zhihui [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Zhang Dabing [School of Life Science and Biotechnology, Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Wu Aibo, E-mail: wuaibo@saas.sh.cn [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China)

    2012-03-30

    Highlight: Black-Right-Pointing-Pointer A visible chromogenic platform for rapid analysis of OP and CM insecticide residues was developed. Black-Right-Pointing-Pointer The assay has the capabilities of both qualitative measurement and quantitative analysis. Black-Right-Pointing-Pointer The sensitivity, capabilities of resisting interferences and storage stability were desirable. Black-Right-Pointing-Pointer Matrix effects were acceptable and detection performance was satisfactory in real application. - Abstract: In this study we propose a chromogenic platform for rapid analysis of organophosphate (OP) and carbamate (CM) insecticide residues, based on recombinant Drosophila melanogaster acetylcholinesterase (R-DmAChE) as enzyme and indoxyl acetate as substrate. The visible chromogenic strip had the advantages identical to those of commonly used lateral flow assays (LFAs) with utmost simplicity in sample loading and result observation. After optimization, depending on the color intensity (CI) values, the well-established assay has the capabilities of both qualitative measurement via naked eyes and quantitative analysis by colorimetric reader with the desirable IC{sub 50} values against the tested six insecticides (0.06 {mu}g mL{sup -1} of carbofuran, 0.28 {mu}g mL{sup -1} of methomyl, 0.03 {mu}g mL{sup -1} of dichlorvos, 31.6 {mu}g mL{sup -1} of methamidophos, 2.0 {mu}g mL{sup -1} of monocrotophos, 6.3 {mu}g mL{sup -1} of omethoate). Acceptable matrix effects and satisfactory detection performance were confirmed by in-parallel LC-MS/MS analysis in different vegetable varieties at various spiked levels of 10{sup -3} to 10{sup 1} {mu}g g{sup -1}. Overall, the testified suitability and applicability of this novel platform meet the requirements for practical use in food safety management and environmental monitoring, especially in the developing world.

  8. Characterization of acetylcholinesterase from the brain of the Amazonian tambaqui (Colossoma macropomum) and in vitro effect of organophosphorus and carbamate pesticides.

    Science.gov (United States)

    Assis, Caio Rodrigo Dias; Castro, Patrícia Fernandes; Amaral, Ian Porto Gurgel; Carvalho, Elba Verônica Matoso Maciel; Carvalho, Luiz Bezerra; Bezerra, Ranilson Souza

    2010-10-01

    In the present study, acetylcholinesterase (AChE) from the brain of the Amazonian fish tambaqui (Colossoma macropomum) was partially characterized and its activity was assayed in the presence of five organophosphates (dichlorvos, diazinon, chlorpyrifos, and tetraethyl pyrophosphate [TEPP]) and two carbamates (carbaryl and carbofuran) insecticides. Optimal pH and temperature were 7.0 to 8.0 and 45°C, respectively. The enzyme retained approximately 70% of activity after incubation at 50°C for 30 min. The insecticide concentration capable of inhibiting half of the enzyme activity (IC50) for dichlorvos, chlorpyrifos, and TEPP were calculated as 0.04 µmol/L, 7.6 µmol/L, and 3.7 µmol/L, respectively. Diazinon and temephos did not inhibit the enzyme. The IC50 values for carbaryl and carbofuran were estimated as 33.8 µmol/L and 0.92 µmol/L, respectively. These results suggest that AChE from the juvenile C. macropomum brain could be used as an alternative biocomponent of organophosphorus and carbamate biosensors in routine pesticide screening in the environment. PMID:20872688

  9. Vortex-Assisted Dispersive Micro-Solid Phase Extraction Using CTAB-Modified Zeolite NaY Sorbent Coupled with HPLC for the Determination of Carbamate Insecticides.

    Science.gov (United States)

    Salisaeng, Pawina; Arnnok, Prapha; Patdhanagul, Nopbhasinthu; Burakham, Rodjana

    2016-03-16

    A vortex-assisted dispersive micro-solid phase extraction (VA-D-μ-SPE) based on cetyltrimethylammonium bromide (CTAB)-modified zeolite NaY was developed for preconcentration of carbamate pesticides in fruits, vegetables, and natural surface water prior to analysis by high performance liquid chromatography with photodiode array detection. The small amounts of solid sorbent were dispersed in a sample solution, and extraction occurred by adsorption in a short time, which was accelerated by vortex agitation. Finally, the sorbents were filtered from the solution, and the analytes were subsequently desorbed using an appropriate solvent. Parameters affecting the VA-D-μ-SPE performance including sorbent amount, sample volume, desorption solvent ,and vortex time were optimized. Under the optimum condition, linear dynamic ranges were achieved between 0.004-24.000 mg kg(-1) (R(2) > 0.9946). The limits of detection (LODs) ranged from 0.004-4.000 mg kg(-1). The applicability of the developed procedure was successfully evaluated by the determination of the carbamate residues in fruits (dragon fruit, rambutan, and watermelon), vegetables (cabbage, cauliflower, and cucumber), and natural surface water. PMID:26915268

  10. Co(II), Ni(II) and Cu(II) complexes of methyl-5-(Phenylthio) benzimidazole-2-carbamate: Molecular structures, spectral and DFT calculations

    Science.gov (United States)

    Mansour, Ahmed M.; El Bakry, Eslam M.; Abdel-Ghani, Nour T.

    2016-05-01

    [Co(FBZ)2(H2O)]·2NO3·0.5H2O (1), [Ni(FBZ)2X2]·zH2O (X = Cl​-, z = 0.5 (2) and X = CH3COO-, z = 1 (3)) and [Cu(FBZ)2(H2O) (NO3)]·NO3·1.5H2O (4) (FBZ = methyl-5-(Phenylthio) benzimidazole-2-carbamate; Fenbendazole) complexes were synthesized and characterized by elemental analysis, thermal, IR, EPR, UV-Vis, magnetic and conductance measurements. Geometry optimization, molecular electrostatic potential maps and natural bond orbital analysis were carried out at DFT/B3LYP/6-31G∗ level of theory. FBZ behaves as a neutral bidentate ligand via the pyridine-type nitrogen of the benzimidazole moiety and the carbamate group. Three-step ionization with pKa values of 3.38, 4.06 and 10.07 were reported for FBZ. The coordination of FBZ to the metal ions led to an increase in the antibacterial activity against the tested Staphylococcus aureus and Escherichia coli bacteria.

  11. Synthesis of novel C17 steroidal carbamates. Studies on CYP17 action, androgen receptor binding and function, and prostate cancer cell growth.

    Science.gov (United States)

    Moreira, Vânia M A; Vasaitis, Tadas S; Guo, Zhiyong; Njar, Vincent C O; Salvador, Jorge A R

    2008-11-01

    We have exploited the reaction of 1,1'-carbonylbis(2-methylimidazole) (CBMI) with several 17beta-hydroxy androstanes to synthesize a series of novel C17 steroidal carbamates. Structural elucidation features have been provided for the final compounds based on 1D and 2D NMR techniques, IR spectroscopy, and related literature. The new compounds were tested for inhibition of human cytochrome 17alpha-hydroxylase-C17,20-lyase (CYP17) and androgen receptor (AR) binding and function effects. Their inhibitory potential against PC-3 cell proliferation was also evaluated. Compounds 11 and 23 were found to inhibit CYP17 with IC50 values of 17.1 and 11.5 microM, respectively. The carbamate moiety at C17 allowed tight binding of the synthesized compounds to both wild-type (wt-) and mutated AR. When bound to the mutated AR, the compounds were found to have a dual effect, stimulating transcription at low concentrations while almost fully blocking it at the higher concentrations tested, in the presence of the natural androgen dihydrotestosterone (DHT). Compounds 8 and 12 were the most active against PC-3 cell proliferation with EC50 values of 2.2 and 0.2 microM, respectively. PMID:18582482

  12. Quantum chemical studies on solvents for post-combustion carbon dioxide capture: calculation of pKa and carbamate stability of disubstituted piperazines.

    Science.gov (United States)

    Gangarapu, Satesh; Wierda, Gerben J; Marcelis, Antonius T M; Zuilhof, Han

    2014-06-23

    Piperazine is a widely studied solvent for post-combustion carbon dioxide capture. To investigate the possibilities of further improving this process, the electronic and steric effects of -CH(3), -CH(2)F, -CH(2)OH, -CH(2)NH(2), -COCH3 , and -CN groups of 2,5-disubstituted piperazines on the pKa and carbamate stability towards hydrolysis are investigated by quantum chemical methods. For the calculations, B3LYP, M11L, and spin-component-scaled MP2 (SCS-MP2) methods are used and coupled with the SMD solvation model. The experimental pK(a) values of piperazine, 2-methylpiperazine, and 2,5-dimethylpiperazine agree well with the calculated values. The present study indicates that substitution of -CH(3), -CH(2) NH(2), and -CH(2) OH groups on the 2- and 5-positions of piperazine has a positive impact on the CO(2) absorption capacity by reducing the carbamate stability towards hydrolysis. Furthermore, their higher boiling points, relative to piperazine itself, will lead to a reduction of volatility-related losses. PMID:24782140

  13. Sequential injection kinetic spectrophotometric determination of quaternary mixtures of carbamate pesticides in water and fruit samples using artificial neural networks for multivariate calibration

    Science.gov (United States)

    Chu, Ning; Fan, Shihua

    2009-12-01

    A new analytical method was developed for the simultaneous kinetic spectrophotometric determination of a quaternary carbamate pesticide mixture consisting of carbofuran, propoxur, metolcarb and fenobucarb using sequential injection analysis (SIA). The procedure was based upon the different kinetic properties between the analytes reacted with reagent in flow system in the non-stopped-flow mode, in which their hydrolysis products coupled with diazotized p-nitroaniline in an alkaline medium to form the corresponding colored complexes. The absorbance data from SIA peak time profile were recorded at 510 nm and resolved by the use of back-propagation-artificial neural network (BP-ANN) algorithms for multivariate quantitative analysis. The experimental variables and main network parameters were optimized and each of the pesticides could be determined in the concentration range of 0.5-10.0 μg mL -1, at a sampling frequency of 18 h -1. The proposed method was compared to other spectrophotometric methods for simultaneous determination of mixtures of carbamate pesticides, and it was proved to be adequately reliable and was successfully applied to the simultaneous determination of the four pesticide residues in water and fruit samples, obtaining the satisfactory results based on recovery studies (84.7-116.0%).

  14. Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    Zhi Mei Liu; Xiao Huan Zang; Wei Hua Liu; Chun Wang; Zhi Wang

    2009-01-01

    A novel method for the determination of five carbamate pesticides(metolcarb,carbofuran,carbaryl,isoprocard and diethofencard)in water samples was developed by dispersive liquid-liquid microextraction(DLLME)coupled with high performance liquid chromatography-diode array detector(HPLC-DAD).Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results.Under the optimum conditions for the method,the calibration curve was linear in the concentration range from 5 to I000 ng mL-1 for all the five carbamate pesticides,with the correlation coefficients(r2)varying from 0.9984 to 0.9994.Good enrichment factors were achieved ranging from 80 to 177-fold,depending on the compound.The limits of detection(LODs)(S/N = 3)were ranged from 0.1 to 0.5 ng mL-1.The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.

  15. Synthesis, structural characterization, docking, lipophilicity and cytotoxicity of 1-[(1R)-1-(6-fluoro-1,3-benzothiazol-2-yl)ethyl]-3-alkyl carbamates, novel acetylcholinesterase and butyrylcholinesterase pseudo-irreversible inhibitors

    Czech Academy of Sciences Publication Activity Database

    Pejchal, V.; Štěpánková, Š.; Pejchalová, M.; Královec, K.; Havelek, R.; Růžičková, Z.; Ajani, Haresh; Lo, Rabindranath; Lepšík, Martin

    Roč. 24, č. 7 ( 2016 ), s. 1560-1572. ISSN 0968-0896 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : halogenated benzothiazole * carbamates * acetylcholinesterase * butyrylcholinesterase inhibition * pseudo-irreversible mechanism * covalent docking Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.793, year: 2014

  16. Examining pyrethroids, carbamates and neonicotenoids in fish, water and sediments from the Indus River for potential health risks.

    Science.gov (United States)

    Jabeen, Farhat; Chaudhry, Abdul Shakoor; Manzoor, Sadia; Shaheen, Tayybah

    2015-02-01

    This 3 × 3 factorial study assessed pyrethroids, carbamates and neonicotenoids groups of pesticides in replicated samples of three fish species from low (S1, reference), medium (S2) and heavy (S3) polluted sites receiving agricultural run-offs around the Indus River. Water and sediment samples from the same sites were also analysed for these pesticides by using high-performance liquid chromatography. Out of nine investigated pesticides, only three pesticides (deltamethrin, carbofuran and cypermethrin) were detected in fish and sediment samples. Deltamethrin in Cyprinus carpio ranged from 0.490 to 0.839 μg/g, mostly exceeding 0.5 μg/g as the maximum residual limit suggested by FAO-WHO, whereas it ranged from 0.214 to 0.318 μg/g in the sampled sediments. The carbofuran concentrations were 0.0425-0.066 and 0.613-0.946 μg/g in Labeo rohita and Channa marulius muscles respectively and 0.069-0.081 μg/g in the corresponding sediment samples. These values were either higher or lower than the maximum limit (0.1 μg/g) as suggested by FAO-WHO. Conversely, the cypermethrin concentration ranged from 0.141 to 0.174 in Ch. marulius and 0.183-0.197 μg/g in sediments which were both below the FAO-WHO maximum limit of 2 μg/g. No pesticide residues were detected in water from these sampling sites. Most selected physicochemical variables were within the acceptable range of World Health Organization for the water quality for aquatic life. The detected pesticide contents were mostly higher in fish muscles from heavily polluted sites. This is worrying because these pesticides may pose health risks for the fish and people of the study area. However, a preliminary risk assessment indicated that the calculated daily intake of detected pesticides by people consuming fish from the Indus River was low and did not present an immediate risk to the fish-consuming people. This study may be used as a benchmark to determine the safety of fish meat in order to develop intervention

  17. Poisoning of raptors with organophosphorus and carbamate pesticides with emphasis on Canada, U.S. and U.K.

    Science.gov (United States)

    Mineau, P.; Fletcher, M.R.; Glaser, L.C.; Thomas, N.J.; Brassard, C.; Wilson, L.K.; Elliott, J.E.; Lyon, L.A.; Henny, C.J.; Bollinger, T.; Porter, S.L.

    1999-01-01

    We reviewed cases of raptor mortality resulting from cholinesterase-inhibiting pesticides. We compiled records from the U.S., U.K. and Canada for the period 1985-95 (520 incidents) and surveyed the relevant literature to identify the main routes of exposure and those products that led to the greatest number of poisoning cases. A high proportion of cases in the U.K. resulted from abusive uses of pesticides (willful poisoning). The proportion was smaller in North America where problems with labeled uses of pesticides were as frequent as abuse cases. Poisoning resulting from labeled use was possible with a large number of granular pesticides and some seed treatments through secondary poisoning or through the ingestion of contaminated invertebrates, notably earthworms. With the more toxic products, residue levels in freshly-sprayed insects were high enough to cause mortality. The use of organophosphorus products as avicides and for the topical treatment of livestock appeared to be common routes of intoxication. The use of insecticides in dormant oils also gave rise to exposure that can be lethal or which can debilitate birds and increase their vulnerability. A few pesticides of high toxicity were responsible for the bulk of poisoning cases. Based on limited information, raptors appeared to be more sensitive than other bird species to organophosphorus and carbamate pesticides. Some of the more significant risk factors that resulted in raptor poisonings were: insectivory and vermivory; opportunistic taking of debilitated prey; scavenging, especially if the gastrointestinal tracts are consumed; presence in agricultural areas; perceived status as pest species; and flocking or other gregarious behavior at some part of their life cycle. Lethal or sublethal poisoning should always be considered in the diagnosis of dead or debilitated raptors even when another diagnosis (e.g., electrocution, car or building strike) is apparent. Many cases of poisoning are not currently

  18. 氯苯甘油氨酯缓释片的稳定性考察%Stability study of chlorphenesin carbamate sustained-release tablets

    Institute of Scientific and Technical Information of China (English)

    卢欣; 王晶晶; 杨金荣; 房志仲

    2011-01-01

    Objective: To build a method in vitro and analyze the stability of chlorphenesin carbamate sustained-release tablets. Methods: Ultraviolet spectrophotometry method was used to determine the drug release of chlorphenesin carbamate sustained-release tablets ire vitro. High performance liquid chromatography method was used to determine the content of chlorphenesin carbamate sustained-release tablets and its related compounds. Results: Under the conditions of stress testing, the appearance, weight, hardness, content, related substance and release rate were stable. Result of accelerated testing and long-term testing showed that tablets with aluminum plastics package bag as package material were stable. Conclusion: The tablets are stable to illumination and high temperature, unstable to humidity. The tablets with moisture resistant packages are stable in acceleration and long-term testing.%目的:建立氯苯甘油氨酯缓释片的体外考察方法,并对其稳定性进行初步考察.方法:采用紫外分光光度法测定氯苯甘油氨酯缓释片体外释放度;采用高效液相色谱法测定氯苯甘油氨酯缓释片的药物含量和有关物质.结果:该制剂在各影响因素的实验条件下,样品的外观、重量、硬度、含量、有关物质、释放度没有明显变化;以铝塑包装袋为包装材料,进行加速、长期实验,制剂的稳定性良好.结论:氯苯甘油氨酯缓释片耐光照、高温,但在高湿条件下不稳定,选用防潮铝塑包装袋包装后,在加速实验和长期实验条件下基本稳定.

  19. Analysis of Ethyl Carbamate in Chinese Wines and Effects of Different Vintage Technologies on the Formation of Ethyl Carbamate%葡萄酒中氨基甲酸乙酯的含量测定及酿造工艺对其含量的影响

    Institute of Scientific and Technical Information of China (English)

    于英; 李记明; 沈志毅; 姜文广

    2012-01-01

    调查了我国干红葡萄酒(77款)和干白葡萄酒(17款)中氨基甲酸乙酯(EC)含量情况,并探讨了酿酒工艺(果胶酶、酵母、乳酸菌和发酵温度等)对葡萄酒中氨基甲酸乙酯(EC)含量的影响。研究结果显示:干红葡萄酒中EC含量范围在7.00~26.80μg/L,平均浓度为17.90μg/L;干白葡萄酒中EC含量范围在6.40~21.58μg/L,平均浓度为11.35μg/L。葡萄酒酿造过程中EC的生成主要受酵母菌和乳酸菌种类的影响,酒精发酵温度的降低和果胶酶的使用有助于减少葡萄酒中EC的含量。%We used solid phase extraction and gas chromatography-flame ionization detector(SPE-GC-FID).Effects of different vintage technologies(pectases,yeasts,malolactic bacterias and fermentation temperature) on the formation of ethyl carbamate in Cabernet Gernischt wines during vinification were studied.The results showed the concentration range of ethyl carbamate in dry red wines was 7.00~26.80 μg/L,and the average was 17.90 μg/L.In dry white wines,the concentration range was 6.40~21.58 μg/L and the average was 11.35 μg/L.The ethyl carbamate is formed mainly from yeasts and malolactic bacterias during winemaking.The lower temperatures of alcoholic fermentation and the supplements of pectases before alcoholic fermentation could contribute to minimize the production of ethyl carbamate in wine.

  20. Liquid chromatography and mass spectrometry for the analysis of N-β-methylamino-L-alanine with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate.

    Science.gov (United States)

    Glover, W Broc; Cohen, Steven A; Murch, Susan J

    2015-01-01

    Numerous studies in the past decade have identified N-β-methylamino-L-alanine (BMAA) as a putative environmental neurotoxin. Produced by cyanobacteria and accumulated at different levels of the trophic system, BMAA has been detected in the brain tissue of human patients that died from progressive neurodegenerative disease. Research into the mechanism of neurotoxicity has been hampered by conflicting results and disagreement in the literature over analytical methods used for quantification and detection. While several research approaches have been tested, the use of the derivatizing reagent 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate is presented here as an effective and selective means for the analysis of BMAA and two co-occurring biological isomers, DAB and AEG, by liquid chromatography and tandem mass spectrometry. PMID:25323521

  1. A review of ethyl carbamate and polycyclic aromatic hydrocarbon contamination risk in cachaça and other Brazilian sugarcane spirits.

    Science.gov (United States)

    Riachi, L G; Santos, A; Moreira, R F A; De Maria, C A B

    2014-04-15

    Sixteen polycyclic aromatic hydrocarbons (PAHs) have been identified in Brazilian sugarcane spirits. Contamination sources are: sugarcane burn before harvest and petroleum derivatives. PAHs concentration in spirits produced from burned cane was about 2-3 times higher than those from unburned cane. Benzo(a)pyrene (BaP) is present at less than 1%, and therefore is not a representative marker of cachaça contamination by PAHs. Ethyl carbamate (EC) is produced during both fermentation and distillation. During distillation, cupric ions may catalyse the conversion of cyanide to EC. In discontinuous distillation, the use of the heart fraction for bottling cachaça considerably decreases its concentration. In the continuous process, in which there is no separation of distillate, it is highly recommended to couple cooling devices and reflux systems to the distillation column. Consumers are at a greater risk of EC exposure from cachaça than from any other spirit. PMID:24295690

  2. tert-Butyl N-[2-(N-isobutyl-4-meth­oxy­benzene­sulfonamido)­eth­yl]carbamate

    OpenAIRE

    Xiao-Guang Bai; Ju-Xian Wang

    2014-01-01

    The title compound, C18H30N2O5S, was synthesized by the reaction of tert-butyl 2-(iso­butyl­amino)­ethyl­carbamate with p-meth­oxy­phenyl­sulfonyl chloride. In the mol­ecule, two intra­molecular C—H⋯O hydrogen bonds are observed. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds involving the imino group N atom and the ester group O atom into chains running parallel to the b axis. The chains are further connected by C—H⋯O hydrogen bonds, forming layers parallel to the bc plane....

  3. Orally bioavailable pyridine and pyrimidine-based Factor XIa inhibitors: Discovery of the methyl N-phenyl carbamate P2 prime group.

    Science.gov (United States)

    Corte, James R; Fang, Tianan; Pinto, Donald J P; Orwat, Michael J; Rendina, Alan R; Luettgen, Joseph M; Rossi, Karen A; Wei, Anzhi; Ramamurthy, Vidhyashankar; Myers, Joseph E; Sheriff, Steven; Narayanan, Rangaraj; Harper, Timothy W; Zheng, Joanna J; Li, Yi-Xin; Seiffert, Dietmar A; Wexler, Ruth R; Quan, Mimi L

    2016-05-15

    Pyridine-based Factor XIa (FXIa) inhibitor (S)-2 was optimized by modifying the P2 prime, P1, and scaffold regions. This work resulted in the discovery of the methyl N-phenyl carbamate P2 prime group which maintained FXIa activity, reduced the number of H-bond donors, and improved the physicochemical properties compared to the amino indazole P2 prime moiety. Compound (S)-17 was identified as a potent and selective FXIa inhibitor that was orally bioavailable. Replacement of the basic cyclohexyl methyl amine P1 in (S)-17 with the neutral p-chlorophenyltetrazole P1 resulted in the discovery of (S)-24 which showed a significant improvement in oral bioavailability compared to the previously reported imidazole (S)-23. Additional improvements in FXIa binding affinity, while maintaining oral bioavailability, was achieved by replacing the pyridine scaffold with either a regioisomeric pyridine or pyrimidine ring system. PMID:27073051

  4. HPLC-MS测定白酒中氨基甲酸酯类农药残留%Determination of carbamates pesticides in liquor by HPLC/MS

    Institute of Scientific and Technical Information of China (English)

    谭文渊; 袁东; 付大友; 李艳清; 王蓉

    2012-01-01

    A HPLC/MS method has been established for the determination of ten carbamates pesticides in liquor. The chromatographic conditions are as follows: Column of Phenomenex-Luna CN 100 A(250 mm×.6 mm×5 pm), and mobile phase was acetonitrile-water(20:80-80:20 within 40 minutes), flow rate was 1.0 mL/min, wavelength was 195 nm, column temperature was 25 ℃ and the injection volume was 20 μl.. MS conditions: Scanning range is 50-350 m/z, temperature of drying gas is 350 %, flow rate of drying gas is 8.0 mL/min, pressure of the evaporative gas is 275.86 kPa. The liquor samples were treated by SPE(solid phase extraction, NH2) and then concentrated by nitrogen-blow. Results showed that the standard curves of ten carbamates were linear over the quality range of 0.05-3 μg/mL, the correlation coefficient r were over 0.99. The average recovery of carbamates were 72.6%-97.6%, RSD were 2.6%-5.9%. Conclusion: this method was accurate, rapid, sensitive for the determination of carbamates pesticides in liquor by HPLC/MS.%建立了一种同时对白酒中10种氨基甲酸酯类农药残留的HPLC-MS测定方法。色谱条件:色谱柱Phenomenex-LunaCN100A(250mm×4.6mm×5μm),流动相乙腈-水(在40min内乙腈由20%变为80%),流速1.00mL/min,检测波长195nm,柱温25℃,进样量20μL。质谱条件:电喷雾离子源(ESI+源),扫描范围(m/z)为50~350,干燥气温度350℃,干燥气流速8.0mL/min,雾化气压力275.86kPa。样品制备:白酒样品用固相萃取处理后,氮吹浓缩,乙腈定容至2mL。结果表明,10种氨基甲酸酯类农药残留在0.05~3μg范围积线性关系良好,相关系数R2〉0.99。平均回收率在72.6%和97.6%,RSD在2.6%~5.9%之间。结论:方法灵敏度高、操作简便、结果准确,可用于酒样中痕量农药残留的含量测定。

  5. A novel and efficient strategy for the synthesis of various carbamates using carbamoyl chlorides under solvent-free and grinding conditions using microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    Hassan Zare; Mohammad Mehdi Ghanbari; Marzieh Jamali; Abdollah Aboodi

    2012-01-01

    We present an efficient,fast and simple strategy of generating the intermediate carbamoyl chlorides from secondary amines using stoichiometric amounts of bis(trichloromethyl)carbonate (BTC) in solution and solvent-free conditions with excellent yields.The results obtained showed the yield increasing on whether a base was used.Finally,an efficient and rapid synthesis of variety carbamate derivatives was developed by the reaction with a high variety of different alcohols,phenols,diols and this intermediate at room temperature with grinding and in solvent-free conditions under microwave irradiation.The presence of various safe bases is shown to be effective in reducing the reaction times,increasing the yields and easing purification.The present method does not involve any azardous phosgene.

  6. 关于氨气提法尿素装置高压甲铵冷凝器配置的分析%Analysis Concerning Arrangement of High Pressure Carbamate Condenser in Urea Plant by Ammonia Stripping Method

    Institute of Scientific and Technical Information of China (English)

    夏炎华; 孙喜; 刘金亮

    2013-01-01

    意大利斯那姆氨气提法工艺自上世纪80年代末期引入我国以来,国内已有近30套氨气提法尿素装置,但国内的氨气提法尿素装置全部采用的是传统的单高压甲铵冷凝器流程,而在国外双高压甲铵汽凝器流程已广泛使用。介绍了单高压甲铵冷凝流程和双高压甲铵冷凝器流程的工艺特点;对比了2种流程的蒸汽平衡及中压蒸汽消耗。结果表明,采用双高压甲铵冷凝流程配置,其吨尿素中压蒸汽消耗比单高压甲铵冷凝器流程低150.31 kg ,节能效果明显。%Since the Italian Snamprogetti ammonia stripping method process has been imported into China at end stage in 1980, there were almost 30 sets of urea plants with ammonia stripping method in China , but in all inland urea plants with ammonia stripping method , the traditional process with sin-gle high pressure carbamate condenser was fully adopted , and the process with double high pressure carbamate condensers was widely used in foreign countries.Author has introduced the process features of single high pressure carbamate condenser and double high pressure carbamate condensers; has compared the steam balance and steam consume for the two kinds of processes.Result indicates that using arrangement of process with double high pres-sure carbamate condensers, the consume of middle pressure steam per ton of urea is 150.31kg lower than that in process with single high pressure carba-mate condenser, the effect for saving energy is obvious.

  7. Curtius rearrangement reactions of 3-(4-azidocarbonyl) phenylsydnone. Synthesis of 4-(sydnon-3-yl) phenyl carbamates, N-aryl-N'-[4-(sydnon-3-yl)] phenyl ureas and their antimicrobial and insecticidal activities

    Indian Academy of Sciences (India)

    P R Latthe; P S Shinge; Bharati V Badami; P B Patil; S N Holihosur

    2006-05-01

    3-[4-(Azidocarbonyl)]phenylsydnone (2) obtained from 3-(4-hydrazinocarbonyl) phenylsydnone (1) on Curtius rearrangement with alcohols, water and amines afforded the corresponding carbamates (3a-h), 4,4'-(sydnone-3-yl) diphenyl urea (4) and 4-(heterocyclyl)phenyl ureas (5a-l). Compounds (5a-l) on one-pot ring conversion yielded the 1,3,4-oxadiazolin-2-one derivatives (6a-l), which on reaction with N2H4 gave the 4-amino-1,2,4-triazolin-3-ones (7a-l). All these compounds exhibited moderate antimicrobial activity against the few microbes tested. The carbamates have been found to be more toxic against fourth instar larvae of Aedes aegypti, in particular, the -butyl derivative (3e).

  8. Métathèse croisée d'alcènes contenant des N-hétéroaryles. Trifluorométhylation d'ène-carbamates cycliques et dérivés

    OpenAIRE

    Lafaye, Kevin

    2015-01-01

    Has now been applied to the synthesis of a wide range of compounds such as polymers, petrochemicals, pharmaceuticals and naturals compounds. A large range of functional groups are well tolerated including alcohols, amides, carbamates and sulfonamides. However, some limitations still have to be overcome Olefin metathesis has emerged has one of the most efficient carbon-carbon bond forming reaction and such as rich N-heteroaryles which are probably causing desactivation of the ruthenium catalys...

  9. Determination of Seven Carbamates Residues in Vegetable by HPLC%高效液相色谱法测定蔬菜中7种氨基甲酸酯类农药残留研究

    Institute of Scientific and Technical Information of China (English)

    王缇; 万妮

    2012-01-01

    [Objective] The aim was to establish an analysis method of carbamates residues. [ Method] The residues of aldiearb sulfone, alrli-carb sulfoxide, methomy), 3-hydroxy-carbofuran, aldiearb, carbofuran and carbryl in vegetable were determined by HPLC with fluorescence detector and post-column derivation, furthermore the fortified recoveries of seven carbamates in vegetable at 0.05, 0.10 and 0. 50 mg/kg were determined. [ Result] The recoveries of seven carbamates in vegetable ranged from 74.6% to 107. 6% , and the precision was less than 10%. [ Conclusion] The method is suitable for the determination of carbamates residues in Chinese cabbage, cucumber, tomato, pepper and celery.%[目的]建立一种氨基甲酸酯类农药残留分析方法.[方法]对市场上蔬菜随机抽样,采用配荧光检测器和柱后衍生系统的高效液相色谱议测定了蔬菜中涕灭威砜、涕灭威亚砜、灭多威、3-羟基克百威、涕灭威、克百威、甲萘威7种氨基甲酸酯类农药的多残留,对每种农药进行了3种不同浓度(0.05、0.10、0.50 mg/kg)的添加回收率试验.[结果]蔬菜中7种农药的回收率在74.6% ~ 107.6%,精密度在10%以内.[结论]该方法可用于大白菜、黄瓜、番茄、辣椒、芹菜等样品中氨基甲酸酯类农药残留分析.

  10. 同位素稀释-GC/MS法测定腐乳中氨基甲酸乙酯含量%Determination of ethyl carbamate in fermented bean curd by GC/MS with isotopic dilution

    Institute of Scientific and Technical Information of China (English)

    王立媛; 吴平谷; 张晶; 汤鋆; 赵永信

    2011-01-01

    Objective:To establish a method for determination of ethyl carbamate in fermented bean curd by isotopic dilution -gas chromatograph - mass spectrometry ( GC/MS). Methods: Ethyl carbamate was determined by gas chromatography -mass spectrometry in selection ion mode after the samples were spiked with D5 - ethyl carbamate and purified by C18 and diatomite solid phase extraction column. Results: The recovery rates were 89% -99% and RSD < 10% , the limit of determination was 2.0 ug/kg. Conclusion: The method is sensitive, accurate and could be used for determination of ethyl carbamate in fermented bean curd.%目的:建立了一种用于腐乳中氨基甲酸乙酯含量的同位素稀释-气相色谱-质谱联用检测方法.方法:采用D5-氨基甲酸乙酯同位素稀释技术,C18和硅藻土固相萃取净化样品,然后用GC/MS测定样品中氨基甲酸乙酯.结果:该方法在腐乳中氨基甲酸乙酯的加标回收率在89%~ 99%之间,相对标准偏差(RSD)小于10%,最低检测限达到2.0μg/kg.结论:方法净化效果好,检测灵敏度、准确度均满足检测要求,可作为腐乳中氨基甲酸乙酯含量检测的确证方法.

  11. The Preparation and Application of Methyl Carbamate through Alcoholysis of Urea%氨基甲酸甲酯的尿素醇解法制备及其应用研究进展

    Institute of Scientific and Technical Information of China (English)

    侯国宁

    2012-01-01

    As a kind of important fine chemicals, methyl carbamate was widely applied in many areas of chemical in- dustry, which was the research focus of urea downstream at present. The research progress of methyl carbamate through al- coholysis of urea such as normal temperature and pressure catalytic synthesis, medium temperature and medium pressure catalytic synthesis and high pressure synthesis without catalyst were generalized. At the same time, its applications on or- ganic synthesis, medicine, and pesticides were reviewed to have a thorough understanding on methyl carbamate industry.%氨基甲酸甲酯作为一种重要的精细化学品,在众多领域中有着广泛的应用,当前已成为尿素下游领域竞相开发的重点。概述了常温常压催化合成、中温中压催化合成及无催化剂高压合成尿素醇解法生产氨基甲酸甲酯工艺研究进展,同时展望其在有机合成、医药、农药等领域的应用,以期对氨基甲酸甲酯行业的发展有较为深入的了解。

  12. Activity-Based Probe for N-Acylethanolamine Acid Amidase.

    Science.gov (United States)

    Romeo, Elisa; Ponzano, Stefano; Armirotti, Andrea; Summa, Maria; Bertozzi, Fabio; Garau, Gianpiero; Bandiera, Tiziano; Piomelli, Daniele

    2015-09-18

    N-Acylethanolamine acid amidase (NAAA) is a lysosomal cysteine hydrolase involved in the degradation of saturated and monounsaturated fatty acid ethanolamides (FAEs), a family of endogenous lipid signaling molecules that includes oleoylethanolamide (OEA) and palmitoylethanolamide (PEA). Among the reported NAAA inhibitors, α-amino-β-lactone (3-aminooxetan-2-one) derivatives have been shown to prevent FAE hydrolysis in innate-immune and neural cells and to reduce reactions to inflammatory stimuli. Recently, we disclosed two potent and selective NAAA inhibitors, the compounds ARN077 (5-phenylpentyl-N-[(2S,3R)-2-methyl-4-oxo-oxetan-3-yl]carbamate) and ARN726 (4-cyclohexylbutyl-N-[(S)-2-oxoazetidin-3-yl]carbamate). The former is active in vivo by topical administration in rodent models of hyperalgesia and allodynia, while the latter exerts systemic anti-inflammatory effects in mouse models of lung inflammation. In the present study, we designed and validated a derivative of ARN726 as the first activity-based protein profiling (ABPP) probe for the in vivo detection of NAAA. The newly synthesized molecule 1 is an effective in vitro and in vivo click-chemistry activity based probe (ABP), which is able to capture the catalytically active form of NAAA in Human Embryonic Kidney 293 (HEK293) cells overexpressing human NAAA as well as in rat lung tissue. Competitive ABPP with 1 confirmed that ARN726 and ARN077 inhibit NAAA in vitro and in vivo. Compound 1 is a useful new tool to identify activated NAAA both in vitro and in vivo and to investigate the physiological and pathological roles of this enzyme. PMID:26102511

  13. Risk assessment of ethyl carbamate in Chinese rice wine among population in five provinces in China%中国5省市居民黄酒中氨基甲酸乙酯的风险评估

    Institute of Scientific and Technical Information of China (English)

    刘爱东; 蒋定国; 周萍萍; 高秀芬; 李建文; 张磊; 刘兆平; 杨大进

    2015-01-01

    Objective To assess the health risk of exposure of ethyl carbamate from rice wine among population in five Chinese southeast provinces and municipalities.Methods The simple distribution method was introduced in dietary exposure assessment of ethyl carbamate derived from rice wine consumed by population aged 18 and above.Subsequently,their health risk assessment was conducted.The consumption data of rice wine from Chinese Nutrition and Health Survey (2002) and the ethyl carbamate concentrate data from a survey in 2010 and 2011 were adopted in dietary exposure assessment.Results The mean and maximum values of ethyl carbamate in rice wine sample were 0.103 and 0.498 mg/kg respectively.The average intake of ethyl carbamate and the margin of exposure (MOE) value among population aged 18 and above were 13.4 ng/kg BW per day and 22 388 respectively.In addition,the average intake of ethyl carbamate in rice wine of consumer only was 427.8 ng/kg BW per day.Therefore,the margin of exposure value was 701.Conclusion For the population aged 18 and above,the health risk caused by ethyl carbamate intake from rice wine was quite low,however,it was rather high among population who consume the rice wine in large quantities.%目的 对中国东南地区5省市居民黄酒中氨基甲酸乙酯暴露的健康风险进行评估.方法 利用2002年中国居民营养与健康状况调查5省市18岁及以上人群黄酒消费量数据,以及2010、2011年在5省市采集黄酒样品的检测结果,采用简单分布膳食暴露评估方法对人群经黄酒摄入氨基甲酸乙酯进行估计,并对造成的健康风险进行评估.结果 5省市黄酒中氨基甲酸乙酯的平均含量为0.103 mg/kg,最大值为0.498 mg/kg.18岁以上人群黄酒氨基甲酸乙酯平均暴露量为13.4 ng/kg BW,暴露限值为22 388.黄酒饮酒者氨基甲酸乙酯平均暴露量为427.8 ng/kg BW,暴露限值为701.结论 18岁及以上全部人群黄酒氨基甲酸乙酯暴露的健康风险较低,

  14. Graphene grafted silica-coated Fe3O4 nanocomposite as absorbent for enrichment of carbamates from cucumbers and pears prior to HPLC.

    Science.gov (United States)

    Sun, Meng; Ma, Xiaoxing; Wang, Juntao; Wang, Weina; Wu, Qiuhua; Wang, Chun; Wang, Zhi

    2013-04-01

    In this paper, a novel graphene (G) grafted silica-coated Fe3O4 nanocomposite was fabricated by the chemical bonding of G onto the surface of silica-coated Fe3 O4 nanoparticles. Some carbamates (metolcarb, carbaryl, pirimicarb, and diethofencarb) in cucumber and pear samples were enriched by this nanocomposite prior to their determination by HPLC with UV detection. Experimental parameters that may affect the extraction efficiency were investigated. Under the optimum conditions, a linear response was achieved in the concentration range of 0.5-100.0 ng/g for metolcarb, carbaryl, and diethofencarb, and 1.0-100 ng/g for pirimicarb with the correlation coefficients (r) ranging from 0.9956 to 0.9984. The LOD (S/N = 3) of the method were found to be in the range from 0.08 to 0.2 ng/g. The RSDs were in the range from 2.4 to 5.8%. The results indicated that the G grafted silica-coated Fe3 O4 nanocomposite was stable and efficient for magnetic SPE and has a great application potential for the preconcentration of other organic pollutants from real samples. PMID:23404952

  15. Microwave accelerated selective Soxhlet extraction for the determination of organophosphorus and carbamate pesticides in ginseng with gas chromatography/mass spectrometry.

    Science.gov (United States)

    Zhou, Ting; Xiao, Xiaohua; Li, Gongke

    2012-07-01

    Microwave accelerated selective Soxhlet extraction (MA-SSE), a novel selective extraction technique, was investigated in this study. A Soxhlet extraction system containing a glass filter was designed as an extractor. During the procedure of MA-SSE, both the target analytes and the interfering components were extracted from the sample into the extraction solvent enhanced by microwave irradiation. After the solvent flowed though the sorbent, the interfering components were adsorbed by the sorbent, and the target analytes remaining in the solvent were collected in the extraction bottle. No cleanup or filtration was required after extraction. The efficiency of the MA-SSE approach was demonstrated in the determination of organophosphorus and carbamate pesticide residues in ginseng by gas chromatography/mass spectrometry (GC/MS). Under the optimized conditions, low limits of detection (0.050-0.50 μg/kg) were obtained. The recoveries were in the range of 72.0-110.1% with relative standard deviations less than 7.1%. Because of the effect of microwave irradiation, MA-SSE showed significant advantage compared with other extraction techniques. The sorbent used in this study showed good cleanup ability. The mechanism of MA-SSE was demonstrated to be based on the rupture of the cell walls according to the structural changes of ginseng samples. On the basis of the results, MA-SSE as a simple and effective sample preparation technique for the analysis of pesticide residues in complex matrixes shows great promise. PMID:22686368

  16. Vibrational frequency analysis, FT-IR, DFT and M06-2X studies on tert-Butyl N-(thiophen-2yl)carbamate

    Science.gov (United States)

    Sert, Yusuf; Singer, L. M.; Findlater, M.; Doğan, Hatice; Çırak, Ç.

    2014-07-01

    In this study, the experimental and theoretical vibrational frequencies of a newly synthesized tert-Butyl N-(thiophen-2yl)carbamate have been investigated. The experimental FT-IR (4000-400 cm-1) spectrum of the molecule in the solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) have been calculated by using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and DFT/M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with the 6-311++G(d,p) basis set by Gaussian 09W software, for the first time. The vibrational frequencies have been assigned using potential energy distribution (PED) analysis by using VEDA 4 software. The computational optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data, and with related literature results. In addition, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies and the other related molecular energy values have been calculated and are depicted.

  17. A DFT study on the functionalization of a BN nanosheet with PCsbnd X, (PC = phenyl carbamate, X = OCH3, CH3, NH2, NO2 and CN)

    Science.gov (United States)

    Beheshtian, Javad; Soleymanabadi, Hamed; Peyghan, Ali Ahmadi; Bagheri, Zargham

    2013-03-01

    By using density functional theory calculations, we investigated the chemical functionalization of a BN nanosheet with different organo-azo derivatives including PCsbnd X, (PC = phenyl carbamate, X = OCH3, CH3, NH2, NO2 and CN) in terms of geometric, energetic, and electronic properties. Reaction energies have been calculated to be in the range of 0.19 to 0.35 eV which is augmented by increasing the electron withdrawing characteristic of the functional groups so that the relative magnitude order is sbnd NO2 > sbnd CN > sbnd OCH3 > sbnd CH3 > sbnd NH2. The chemical functionalization leads to a decrease in HOMO/LUMO energy gap of BN sheet especially after adsorption of PCsbnd NO2 by about 1.88 eV. Conduction level and Fermi level of the BN sheet are shifted to lower energies upon the functionalization of the sheet with PCsbnd NO2 and PCsbnd CN, thus, it leads to an increment in work function of the sheet, impeding the field electron emission.

  18. The Methylene Alkoxy Carbamate Self-Immolative Unit: Utilization for the Targeted Delivery of Alcohol-Containing Payloads with Antibody-Drug Conjugates.

    Science.gov (United States)

    Kolakowski, Robert V; Haelsig, Karl T; Emmerton, Kim K; Leiske, Chris I; Miyamoto, Jamie B; Cochran, Julia H; Lyon, Robert P; Senter, Peter D; Jeffrey, Scott C

    2016-07-01

    A strategy for the conjugation of alcohol-containing payloads to antibodies has been developed and involves the methylene alkoxy carbamate (MAC) self-immolative unit. A series of MAC β-glucuronide model constructs were prepared to evaluate stability and enzymatic release, and the results demonstrated high stability at physiological pH in a substitution-dependent manner. All the MAC model compounds efficiently released alcohol drug surrogates under the action of β-glucuronidase. To assess the MAC technology for ADCs, the potent microtubule-disrupting agent auristatin E (AE) was incorporated through the norephedrine alcohol. Conjugation of the MAC β-glucuronide AE drug linker to the anti-CD30 antibody cAC10, and an IgG control antibody, gave potent and immunologically specific activities in vitro and in vivo. These studies validate the MAC self-immolative unit for alcohol-containing payloads within ADCs, a class that has not been widely exploited. PMID:27198854

  19. Synthesis and Bioevaluation of 3-(substitutedphenyl-1-(4-hydroxyphenyl-2-propen-1-ones and their Carbamate Derivatives against Root – Knot Nematode (Meloidogyne javanica

    Directory of Open Access Journals (Sweden)

    Sumona Kumari

    2014-09-01

    Full Text Available Synthesis of 3-(4-chloro/methyl/nitro/methoxy/3,4,5-trimethoxy/2,4-dichloro/ 4-bromo/ 3, 4-dimethoxy/ 2, 4-dimethoxy/ 3-bromo/ 2-chloro/ 2-methoxy phenyl-1-(4-hydroxyphenyl-2-propen-1-one (14-25 has been carried out from substituted benzaldehyde (1-12 and 4-hydroxy acetophenone (13. The condensation of synthesized 2-propen-1-ones (14-25 with phenyl isocyanate (26 gave 4-[3-(4-chloro/ methyl/nitro/methoxy/3, 4, 5-trimethoxy/2, 4-dichloro/4-bromo/3, 4-dimethoxy/2, 4-dimethoxy/3-bromo phenyl prop-2-enoyl] phenyl phenylcarbamate (27-36. The synthesized compounds were characterized on the basis of analytical and spectral data. All the compounds were evaluated for their nematicidal activity in- vitro against second stage juveniles (J2 of root - knot nematode (Meloidogyne javanica. Incorporation of carbamoyloxy moiety in 2-propen-1-ones enhanced the activity. Irrespective of the concentration, compounds 3-(4-methoxyphenyl-1-(4-hydroxyphenyl-2-propen-1-one (17 and 4-[3-(4-methoxyphenyl prop-2-enoyl] phenyl phenyl carbamate (30 have shown maximum nematode mortality i.e. 30% and 51.8%.

  20. 酱油中氨基甲酸乙酯和氯丙醇含量调查与分析%Survey and analysis of ethyl carbamate and 3-chloro-1,2-propanediol (3-MCPD) in soy sauce

    Institute of Scientific and Technical Information of China (English)

    王立媛; 吴平谷; 张晶; 汤鋆; 赵永信

    2012-01-01

    Objective:To investigate the levels of 3 - chloro - 1,2 - propanediol(3 - MCPD) and ethyl carbamate in soy sauce. Methods: The total 135 soy sauce samples were collected from big, middle - sized and small supermarkets and farmer's market respectively. The 3 - chloro - 1,2 - propanediol(3 - MCPD) and ethyl carbamate were measured by gas chromatography - mass spectrometry in selection ion mode, after the samples were coupled with D5 - ethyl carbamate and D5 - 3 - chloro -1,2- propanediol ( 3 - MCPD ) , and purified by diatomite solid phase extraction coulum. Results: The results showed that ethyl carbamate was detected in all samples ( 100% ) with the range from 1. 6 μg/kg to 80. 8 μg/kg,the 3 - chloro - 1,2 - propanediol( 3 - MCPD) was detected in 32.05% of the samples with the range from 5. 8 μg/kg to 379. 10 μg/kg. Conclusion: In this investigation, the ethyl carbamate was detected in all soy sauce samples, and the level of 3 - chloro - 1,2 - propanediol(3 - MCPD) was not pretty low, and the data obtained in our test can be the references for risk assessment of ethyl carbamate and 3 - chloro - 1 ,2 - propanediol in soy sauce.%目的:调查本地市售酱油中氯丙醇和氨基甲酸乙酯含量.方法:在本市大、中、小超市及农贸市场采集135份酱油,采用d5-3-氯-1,2-丙二醇、D5-氨基甲酸乙酯同位素稀释技术,硅藻土固相萃取净化样品,然后用GC/MS测定样品中氯丙醇和氨基甲酸乙酯.结果:135份酱油中氨基甲酸乙酯检出率100%,含量范围为1.6 μg/kg~80.8 μg/kg;氯丙醇检出率为32.05%,含量范围为5.8 μg/kg~ 379.10 μg/kg.结论:本次调查显示酱油中均存在氨基甲酸乙酯,氯丙醇检出含量也不低,为开展酱油中氨基甲酸乙酯和氯丙醇的风险评估提供了基础数据.

  1. 新型氨基甲酸乙酯人工抗原的分析表征方法研究%Analysis and Characterization of a Novel Artificial Antigen of Ethyl Carbamate

    Institute of Scientific and Technical Information of China (English)

    郭明; 周伟; 周珊; 敬娇; 杨萍

    2013-01-01

    A novel artificial antigen of ethyl carbamate( EC) was synthesized by l-(3-dimethylaminopropyl)-3-ethyl carbon carbodiimide method, and ATR-FTIR was applied to the characterization of the coupling effects of EC and the secondary structure change of the carrier protein combined with fluorescence spectrometry. The coupling ratio of the hapten molecules with the carrier protein of the new artificial antigen of ethyl carbamate was determined by MALDI-TOF-MS together with UV spectroscopy and electrophoresis method. The results showed that the synthetic route of the design was reasonable and a new artificial antigen of ethyl carbamate was successfully prepared. There was a variation in the content of α-helix, β-sheet and β-turn of artificial antigen compared with the carrier protein molecules. The "fluorescence phase diagram" of the artificial antigen was conformed to transitional relations of linear types, in line with the "all or none" pattern. The results of charac?terization of the artificial antigen of ethyl carbamate by ATR-FTIR and MALDI-TOF-MS were consistent with that of using other spectroscopic methods and electrophoresis methods. The coupling ratio of the artificial anti?gen calculated is 15:1-19:1 and the titer of antiserum by mice immunized with EC was 1:25600. The results of this work may provide a useful reference for the techniques of preparation and characterization of the artifi?cial antigen of ethyl carbamate.%采用1-(3-二甲氨基丙基)-3-乙基碳二亚胺方法合成氨基甲酸乙酯(Ethyl carbamate,EC)新型人工抗原.将衰减全反射红外光谱法(ATR-FTIR)应用于人工合成抗原的表征分析,并结合荧光光谱分析EC人工抗原的偶联效果以及载体蛋白质分子的二级结构变化;通过质谱结合紫外光谱、电泳方法进行人工抗原的系统表征,计算新型人工抗原中半抗原分子与载体蛋白质分子的偶联比.结果表明:合成路线合理,成功获得了氨基甲酸乙酯新型人

  2. Research progress on toxicity and contamination of ethyl carbamate in fermented foods%发酵食品中氨基甲酸乙酯污染及其毒性研究进展

    Institute of Scientific and Technical Information of China (English)

    崔霞; 苗虹; 赵云峰; 吴永宁

    2014-01-01

    氨基甲酸乙酯(ethyl carbamate, EC)是在食品发酵过程中产生的一种化学污染物,广泛存在于发酵食品和酒精饮料中。对于啮齿类动物,氨基甲酸乙酯是一种多位点致癌物,可以导致动物发生肺癌、淋巴癌、肝癌和皮肤癌等疾病。国际癌症研究机构(IARC)已将其认定为2A 级致癌物,鉴于其对人类具有潜在的致癌性,氨基甲酸乙酯污染已成为近年来国际社会高度关注的食品安全热点问题之一。本文总结了当前国内外氨基甲酸乙酯的研究现状,对其理化特性、代谢途径、毒性、在发酵食品中的污染情况及各国限量标准进行了综述。最后建议我国相关部门应积极开展氨基甲酸乙酯安全问题调查和研究,帮助企业改进生产工艺,建立国家限量标准,以利于与国际接轨,促进我国发酵食品相关工业长期健康发展。%Ethyl carbamate is a kind of chemical contaminants which is formed as a by-product of fermentation processes, with widespread occurrence in fermented foods and alcoholic beverages. For the rodent animal, ethyl carbamate is recognized as a multisite carcinogen, which can cause lung cancer, lymphatic cancer, liver cancer, skin cancer and other diseases in animals. Recently, International Agency for Research on Cancer (IARC) upgraded its classification of ethyl carbamate to group 2A. On considering of its potential carcinogenicity to humans, ethyl carbamate pollution has become one of the hot issues of food safety in the world. The present paper summarized the current status of research about ethyl carbamate, and gave a review from the following aspects: the contamination level in fermented foods, limits of each states, metabolic pathways, and toxicity and so on. Finally, we suggested the relation departments should carry out the food safety surveys and studies about EC actively. In order to meet the international standards and facilitate the long-term healthy development of

  3. 1-[(Biphenyl-4-yl(phenylmethyl]-1H-imidazole (bifonazole

    Directory of Open Access Journals (Sweden)

    Lynne S. Taylor

    2010-10-01

    Full Text Available In the title compound, C22H18N2, the dihedral angles formed by the imidazole ring with the phenyl ring and the benzene ring of the biphenyl group are 87.02 (5 and 78.20 (4°, respectively. In the crystal, molecules interact through intermolecular C—H...N hydrogen bonds, forming chains parallel to the b axis. These chains are further linked into a three-dimensional network by C—H...π stacking interactions

  4. Determination of 7 carbamate pesticides in water by solid phase extraction-gas chromatography%固相萃取-气相色谱法测定水中7种氨基甲酸酯农药

    Institute of Scientific and Technical Information of China (English)

    周伦敏; 陆昱养; 何云亚

    2013-01-01

    目的:建立应用气相色谱-氮磷检测器结合固相萃取测定水中7种氨基甲酸酯农药的方法.方法:水样经ENVI-Carb固相萃取柱富集,以二氯甲烷+丙酮(1+1)洗脱,采用DB-1701毛细管柱和氮磷检测器进行检测.结果:7种氨基甲酸酯农药在DB-1701毛细管柱上均能得到很好分离,回收率在82.0%~101.5%,相对标准偏差为2.9%~10.5%.结论:本方法简便、快速、灵敏,可用于水中氨基甲酸酯农药的检测.%Objective:To establish a method for determination of 7 carbamate pesticides in water by gas chromatography-nitrogen phosphorus detector combined with solid-phase extraction.Methods:The target pesticides in water samples were enrichmented with ENVI-Carb solid phase extraction column,and eluted with dichloromethane and acetone(1 + 1),and separated with DB-1701 capillary column and detected with GC-NPD.Results:Seven carbamate pesticides could be well separated,the recovery rates were 82.0% ~ 101.5%,with the relative standard deviation of 2.9% ~ 10.5%.Conclusion:This method was simple,rapid and sensitive and it can be applied for analysis of carbamate pesticides in water.

  5. Amino acids

    Science.gov (United States)

    Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

  6. Estimativa da incerteza de medição em análise cromatográfica: abordagem sobre a quantificação de carbamato de etila em cachaça The measurement uncertainty estimation in chromatographic analisys: approach on the quantification of ethyl carbamate in " cachaça"

    Directory of Open Access Journals (Sweden)

    Marcus Henrique Campino de la Cruz

    2010-01-01

    Full Text Available The measurement uncertainty is useful to estimate the confidence of analytical results. Nowadays, a result without the uncertainty statement cannot be considered reliable, but the scientific literature still lacks examples of the estimate of the measurement uncertainty. This paper presents a practical and reliable description of the measurement uncertainty estimation of the analytical determination of ethyl carbamate in cachaça by GC-IDMS. The isotope dilution technique (ID associated with GC-MS was used to improve the accuracy. The uncertainty estimated corresponds to 10% of the mass fraction of ethyl carbamate (115 ± 11 ng/g, which is in agreement with ppb level.

  7. Study on carbamate pesticides by capillary electrophoresis with laser-induced fluorescence detection%CE-LIF在氨基甲酸酯类农药研究中的应用

    Institute of Scientific and Technical Information of China (English)

    杨玉林; 赵晓寅; 赵文杰; 周天舒

    2012-01-01

    用毛细管电泳激光诱导荧光检测法(CE-LIF),对灭除威(XMC)、混杀威(2,3,5-trime-thacarb)和灭虫威(mercaptodimethur)等3种氨基甲酸酯类农药进行了研究.在碱性条件下,氨基甲酸酯类农药水解产生甲胺并与荧光衍生试剂4-氯-7-硝基-2,1,3-苯并二唑(NBD-Cl)发生衍生化反应,产物经毛细管电泳激光诱导荧光检测法测定.对影响水解、衍生以及毛细电泳分离的因素如缓冲液酸度、浓度和衍生试剂的浓度等进行了详细讨论;在最佳条件下,3种农药的检出限分别可达3.0×10-9、1.0×10-9和3.0×10-9 mol/L,并测定了它们的水解速率常数及活化能.该方法不仅可对氨基甲酸酯类农药进行测定,同时也可用于对这类农药的一些理化常数的测定.%A sensitive and rapid capillary electrophoresis method with laser-induced fluorescence detection (CE-LIF) was developed for the determination of carbamate pesticides (including (3,5-dimethylphenyl) N-methylcarbamate (XMC), and mercaptodimethur). In alkaline solution, carbamate was hydrolyzed to methylamine, which can be derivatized by 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-C1) and detected by CE-LIF. Several parameters which influence the hydrolysis, derivatization and electrophoresis separation, such as pH, concentration of buffer solution and concentration of NBD-C1, were investigated. The detection limits of the three carbamates were 3. 0×10-9, 1. 0 ×10-9 and 3. 0 ×10-9 mol/L, respectively. The proposed method was successfully employed to determine the rate constants and activation energies for carbamates hydrolysis.

  8. The Stress Corrosion Characteristics of the High-Pressure Ammonium Carbamate Condenser E104 and It's Leakage Treatment%高压甲铵冷凝器 E104应力腐蚀特点及泄漏处理

    Institute of Scientific and Technical Information of China (English)

    刘志勇; 朱建宇

    2014-01-01

    针对氨汽提法尿素装置高压甲铵冷凝器腐蚀的特点,结合高压甲铵冷凝器的运行状况,探讨查漏方案及对策,以及操作维护方面的注意事项。%Combining the corrosion characteristics of the high-pressure ammonium carbamate condenser E104 in the ammonia stripping urea plant with it's operation ,discuss the leakage detection method and countermeasures ,precautions of operation and maintenance .

  9. Rapid and sensitive suspension array for multiplex detection of organophosphorus pesticides and carbamate pesticides based on silica–hydrogel hybrid microbeads

    International Nuclear Information System (INIS)

    Highlights: • Silica–hydrogel hybrid microbeads were used to develop suspension array. • The results in detecting pesticides agree well with those from LC–MS/MS. • The method showed the good capability for multiplex analysis of pesticides residues. - Abstract: A technique for multiplex detection of organophosphorus pesticides and carbamate pesticides has been developed using a suspension array based on silica–hydrogel hybrid microbeads (SHHMs). The main advantage of SHHMs, which consist of both silica and hydrogel materials, is that they not only could be distinguished by their characteristic reflection peak originating from the stop-band of the photonic crystal but also have low non-specific adsorption of proteins. Using fluorescent immunoassay, the LODs for fenitrothion, chlorpyrifos-methyl, fenthion, carbaryl and metolcarb were measured to be 0.02 ng/mL, 0.012 ng/mL, 0.04 ng/mL, 0.05 ng/mL and 0.1 ng/mL, respectively, all of which are much lower than the maximum residue limits, as reported in the European Union pesticides database. All the determination coefficients for these five pesticides were greater than 0.99, demonstrating excellent correlations. The suspension array was specific and had no significant cross-reactivity with other chemicals. The results for the detection of pesticide residues collected from agricultural samples using this method agree well with those from liquid chromatography–tandem mass spectrometry. Our results showed that this simple method is suitable for simultaneous detection of these five pesticides residues in fruits and vegetables

  10. Rapid and sensitive suspension array for multiplex detection of organophosphorus pesticides and carbamate pesticides based on silica–hydrogel hybrid microbeads

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuan [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China); Mu, Zhongde; Shangguan, Fengqi [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu (China); Liu, Ran; Pu, Yuepu [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China); Yin, Lihong, E-mail: lhyin@seu.edu.cn [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China)

    2014-05-01

    Highlights: • Silica–hydrogel hybrid microbeads were used to develop suspension array. • The results in detecting pesticides agree well with those from LC–MS/MS. • The method showed the good capability for multiplex analysis of pesticides residues. - Abstract: A technique for multiplex detection of organophosphorus pesticides and carbamate pesticides has been developed using a suspension array based on silica–hydrogel hybrid microbeads (SHHMs). The main advantage of SHHMs, which consist of both silica and hydrogel materials, is that they not only could be distinguished by their characteristic reflection peak originating from the stop-band of the photonic crystal but also have low non-specific adsorption of proteins. Using fluorescent immunoassay, the LODs for fenitrothion, chlorpyrifos-methyl, fenthion, carbaryl and metolcarb were measured to be 0.02 ng/mL, 0.012 ng/mL, 0.04 ng/mL, 0.05 ng/mL and 0.1 ng/mL, respectively, all of which are much lower than the maximum residue limits, as reported in the European Union pesticides database. All the determination coefficients for these five pesticides were greater than 0.99, demonstrating excellent correlations. The suspension array was specific and had no significant cross-reactivity with other chemicals. The results for the detection of pesticide residues collected from agricultural samples using this method agree well with those from liquid chromatography–tandem mass spectrometry. Our results showed that this simple method is suitable for simultaneous detection of these five pesticides residues in fruits and vegetables.

  11. Assignment of the Sub-Millimeter Wave Spectrum of Methyl Carbamate, NH_2COOCH_3, in the First Excited State of the Methyl Group Internal Rotation

    Science.gov (United States)

    Groner, P.

    2009-06-01

    The rotational spectrum of methyl carbamate in the first excited torsional state (up to 149 GHz) has been analyzed recently for rotational quantum number J up to 20 together with transitions in the ground state. An extended analysis of the rotational spectrum in the ground state between 10 and 371 GHz with over 6000 transitions with J up to 60 has also been published. In the spectra recorded at that time by the FASSST method, about 3000 transitions belonging to the first torsional excited state of the methyl group have now been assigned and analyzed, about half of them belonging to the E torsional species. Both the newly assigned and previously published transitions have been used to fit less than 45 spectroscopic parameters of an effective rotational Hamiltonian for such systems, achieving a dimensionless standard deviation of 1.33. A somewhat unexpected result was the value of the {ρ} parameter of 0.063628(20) which differed significantly from the value obtained for the ground state of 0.058791(15). The discrepancy will be investigated in the near future. Hopefully, a resolution of the problem can be achieved by a combined fit of all excited and ground state transitions using common {ρ} and {β} parameters with {β} as the angle between the {ρ}-axis and the a principal axis. V. Ilyushin, E. Alekseev, J. Demaison, I. Kleiner, J. Mol. Spectrosc. 240, 127 (2006). P. Groner, M. Winnewisser, I. R. Medvedev, F. C. De Lucia, E. Herbst, K. V. L. N. Sastry, Astrophys. J. Suppl. Ser. 169, 28 (2007). P. Groner, J. Chem. Phys. 107, 4483 (1997).

  12. (1S,3S,4S-tert-Butyl N-[1-benzyl-3-hydroxy-5-phenyl-4-(picolinamidopentyl]carbamate

    Directory of Open Access Journals (Sweden)

    Jian-Feng Zheng

    2008-07-01

    Full Text Available The title compound, C29H35N3O4, was obtained by the reaction of (2S,4S,5S-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentylcarbamate and picolinic acid using oxalyl chloride as a chlorinating reagent to activate the carboxyl group. In the crystal structure there are two molecules in the asymmetric unit, which are aligned edge-to-face. In one molecule, the pyridyl ring forms a dihedral angle of 22.0 (1° with the phenyl ring of the terminal benzyl group and 14.3 (1° with the other phenyl ring; in the other molecule, the corresponding angles are 12.1 (1 and 10.6 (1°, respectively. The packing is stabilized by intermolecular hydrogen bonds and C—H...π interactions.

  13. Applicability of a carbamate insecticide multiresidue method for determining additional types of pesticides in fruits and vegetables.

    Science.gov (United States)

    Krause, R T; August, E M

    1983-03-01

    Several fruits and vegetables were fortified at a low (0.02-0.5 ppm) and at a high (0.1-5 ppm) level with pesticides and with a synergist, and recoveries were determined. Analyses were performed by using 3 steps of a multiresidue method for determining N-methylcarbamates in crops: methanol extraction followed by removal of plant co-extractives by solvent partitioning and chromatography with a charcoal-silanized Celite column. Eleven compounds were determined by using a high performance liquid chromatograph equipped with a reverse phase column and a fluorescence detector. Twelve additional compounds were determined by using a gas-liquid chromatograph equipped with a nonpolar packed column and an electron capture or flame photometric detector. Recoveries of 10 pesticides (azinphos ethyl, azinphos methyl, azinphos methyl oxygen analog, carbaryl, carbofuran, naphthalene acetamide, naphthalene acetic acid methyl ester, napropamide, phosalone, and phosalone oxygen analog) and the synergist piperonyl butoxide, which were determined by high performance liquid chromatography, averaged 100% (range 86-117) at the low fortification level and 102% (range 93-115) at the high fortification level. Quantitative recovery of naphthalene acetamide through the method required that an additional portion of eluting solution be passed through the charcoal column. Recoveries of 7 additional pesticides (dimethoate, malathion, methyl parathion, mevinphos, parathion, phorate oxygen analog, and pronamide), which were determined by gas-liquid chromatography (GLC), averaged 108% (range 100-120) at the low fortification level and 107% (range 99-122) at the high fortification level. DDT, diazinon, dieldrin, phorate, and pirimiphos ethyl, which were determined by GLC, were not quantitatively recovered. PMID:6853408

  14. Point mutations associated with organophosphate and carbamate resistance in Chinese strains of Culex pipiens quinquefasciatus (Diptera: Culicidae.

    Directory of Open Access Journals (Sweden)

    Minghui Zhao

    Full Text Available Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1 was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A. Analysis of the correlation between mutation frequencies and resistance levels (LC50 suggests that two point mutations, G247S (r2 = 0.732, P = 0.065 and A328S (r2 = 0.891, P = 0.016, are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036. And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045 resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.

  15. 氨基甲酸酯的抗磨性能及其作用机理的研究%Mechanism and performance of anti-wear properties of diamyl carbamate

    Institute of Scientific and Technical Information of China (English)

    胡洁; 于宁; 杨翰林; 刘蕊; 陈化飞; 许玲玲; 宋应金

    2014-01-01

    采用四球试验机评价二戊基氨基甲酸酯单组分化合物在成品油中的抗磨性能,并通过X射线光电子能谱( XPS)分析了边界润滑膜的形成机理及作用机理。结果表明,二戊基氨基甲酸酯与ZD-DP及硼酸酯具有优良的复合效应,且在溶剂精制基础油中具有良好的感受性。%The anti-wear properties of diamyl carbamate in refine d oil product were evaluated by four-ball machine .The formation mechanism and action mechanism of boundary film were analysized by X-ray photoelectronic spectroscopy ( XPS) .The results showed that the dia-myl carbamate , ZDDP and borate ester had excellent composite effect .Moreover , they had good sensitivity in solvent refined base oil .

  16. Synthesis, structure-activity, and structure-stability relationships of 2-substituted-N-(4-oxo-3-oxetanyl) N-acylethanolamine acid amidase (NAAA) inhibitors.

    Science.gov (United States)

    Vitale, Romina; Ottonello, Giuliana; Petracca, Rita; Bertozzi, Sine Mandrup; Ponzano, Stefano; Armirotti, Andrea; Berteotti, Anna; Dionisi, Mauro; Cavalli, Andrea; Piomelli, Daniele; Bandiera, Tiziano; Bertozzi, Fabio

    2014-02-01

    N-Acylethanolamine acid amidase (NAAA) is a cysteine amidase that preferentially hydrolyzes saturated or monounsaturated fatty acid ethanolamides (FAEs), such as palmitoylethanolamide (PEA) and oleoylethanolamide (OEA), which are endogenous agonists of nuclear peroxisome proliferator-activated receptor-α (PPAR-α). Compounds that feature an α-amino-β-lactone ring have been identified as potent and selective NAAA inhibitors and have been shown to exert marked anti-inflammatory effects that are mediated through FAE-dependent activation of PPAR-α. We synthesized and tested a series of racemic, diastereomerically pure β-substituted α-amino-β-lactones, as either carbamate or amide derivatives, investigating the structure-activity and structure-stability relationships (SAR and SSR) following changes in β-substituent size, relative stereochemistry at the α- and β-positions, and α-amino functionality. Substituted carbamate derivatives emerged as more active and stable than amide analogues, with the cis configuration being generally preferred for stability. Increased steric bulk at the β-position negatively affected NAAA inhibitory potency, while improving both chemical and plasma stability. PMID:24403170

  17. The Repellent DEET Potentiates Carbamate Effects via Insect Muscarinic Receptor Interactions: An Alternative Strategy to Control Insect Vector-Borne Diseases.

    Directory of Open Access Journals (Sweden)

    Aly Abd-Ella

    Full Text Available Insect vector-borne diseases remain one of the principal causes of human mortality. In addition to conventional measures of insect control, repellents continue to be the mainstay for personal protection. Because of the increasing pyrethroid-resistant mosquito populations, alternative strategies to reconstitute pyrethroid repellency and knock-down effects have been proposed by mixing the repellent DEET (N,N-Diethyl-3-methylbenzamide with non-pyrethroid insecticide to better control resistant insect vector-borne diseases. By using electrophysiological, biochemichal, in vivo toxicological techniques together with calcium imaging, binding studies and in silico docking, we have shown that DEET, at low concentrations, interacts with high affinity with insect M1/M3 mAChR allosteric site potentiating agonist effects on mAChRs coupled to phospholipase C second messenger pathway. This increases the anticholinesterase activity of the carbamate propoxur through calcium-dependent regulation of acetylcholinesterase. At high concentrations, DEET interacts with low affinity on distinct M1/M3 mAChR site, counteracting the potentiation. Similar dose-dependent dual effects of DEET have also been observed at synaptic mAChR level. Additionally, binding and in silico docking studies performed on human M1 and M3 mAChR subtypes indicate that DEET only displays a low affinity antagonist profile on these M1/M3 mAChRs. These results reveal a selective high affinity positive allosteric site for DEET in insect mAChRs. Finally, bioassays conducted on Aedes aegypti confirm the synergistic interaction between DEET and propoxur observed in vitro, resulting in a higher mortality of mosquitoes. Our findings reveal an unusual allosterically potentiating action of the repellent DEET, which involves a selective site in insect. These results open exciting research areas in public health particularly in the control of the pyrethroid-resistant insect-vector borne diseases. Mixing low

  18. The metabolism of the non-proteinogenic amino acid β-N-methylamino-L-alanine (BMAA) in the cyanobacterium Synechocystis PCC6803.

    Science.gov (United States)

    Downing, Simoné; Downing, Timothy Grant

    2016-06-01

    The neurotoxic amino acid β-N-methylamino-L-alanine (BMAA) is produced by cyanobacteria under nitrogen starvation conditions and its metabolism is closely associated with cellular nitrogen control. Very little is known regarding the metabolism or biosynthesis of this amino acid in the producing organisms and current knowledge is limited to the spontaneous formation of carbamate adducts in the presence of aqueous carbon dioxide, the rapid removal of free cellular BMAA upon the addition of ammonia to nitrogen-starved cyanobacterial cultures, and the link between cellular nitrogen status and BMAA synthesis. Data presented here show that exogenous BMAA is readily metabolised by cyanobacteria during which, the primary amino group is rapidly transferred to other cellular amino acids. Furthermore, data suggest that BMAA is metabolised in cyanobacteria via a reversible transamination reaction. This study presents novel data on BMAA metabolism in cyanobacteria and provides the first proposed biosynthetic precursor to BMAA biosynthesis in cyanobacteria. PMID:26948425

  19. 2010年杭州市售发酵性食品中氨基甲酸乙酯调查与分析%Survey and analysis of ethyl carbamate in commercial fermented foods in Hangzhou in 2010

    Institute of Scientific and Technical Information of China (English)

    吴平谷; 杨大进; 沈向红; 王立媛; 潘晓冬; 张晶; 赵永信; 谭莹

    2011-01-01

    Objective To observe the ethyl carbamate concentrations in different commercial fermented foods in Hangzhou in 2010.Methods In 2010,237 commercial fermented food samples of eight categories,including yellow wine,white spirit,wine,beer,cooking wine,sauce,vinegar and fermented bean curd,were purchased from 3 different size markets respectively in Hangzhou.The ethyl carbamate was measured by gas chromatography-mass spectrometry in selection ion mode,after the samples were coupled with D5-ethyl carbamate,and purified by diatomite solid phase extraction column.Results The results showed that ethyl carbamate was detected in all samples analyzed (100%) with the range from 2.0 μg/kg to 515.0 μg/kg.The ethyl carbamate average(median)levels in 8 food catergories were descending with fermented red bean curd (182.2 μg/kg (161.2 μg/kg)),yellow wine (159.6 μg/kg (121.0 μg/kg)),cooking wine (86.8 μg/kg (95.6 μg/kg)),white spirit (72.0 μg/kg (60.5 μg/kg)),soy sauce (47.2 μg/kg(40.7μg/kg)),vinegar (26.7 μg/kg (31.8 μg/kg)),wine (15.7 μg/kg (16.8 μg/kg)) and beer (2.2 μg/kg (2.3 μg/kg)).Conclusion The ethyl carbamate was detected in all fermented foods in Hangzhou in 2010,and the levels of ethyl carbamate in red bean curd and yellow wine were higher than others.%目的 调查2010年杭州市售发酵性食品中氨基甲酸乙酯含量.方法 2010年在杭州大、中、小型3家超市采集237份发酵性食品,包括黄酒、白酒、葡萄酒、啤酒、料酒、酱油、食醋、腐乳等8类食品,采用D5-氨基甲酸乙酯核素稀释技术,硅藻土固相萃取净化样品,然后用气相色谱-质谱法测定样品中氨基甲酸乙酯.结果 237份发酵性食品中氨基甲酸乙酯检出率为100%,含量范围为2.0 ~515.0 μg/kg,氨基甲酸乙酯含量平均值(中位数)从高到低依次为红腐乳[182.2 μg/kg(161.2 μg/kg )]、黄酒[159.6 μg/kg(121.0 μg/kg)]、料酒[86.8 μg/kg(95.6 μg/kg)]、白酒[72.0 μg/kg(60.5 μg/kg )]、酱油[47

  20. Acid Rain.

    Science.gov (United States)

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  1. Structure and Vibrational Spectra of Tert-butyl N-(2- bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate%Tert-butyl(N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate的结构和振动光谱

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The molecular structure, conformational stability, and vibrational frequencies of tert-butyl N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate (TBBFC) were investigated by utilizing the Hartree-Fock (HF) and density functional theory (DFT) ab initio calculations with 6-31G* and 6-31G* * basis sets. The optimized bond length and angle values obtained by HF method showed the best agreement with the experimental values. Comparison of the observed and calculated fundamental vibrational frequencies indicated that B3LYP was superior to the scaled HF approach for molecular problems. Optimal uniform scaling factors calculated for the title compound are 0.899/0.904,0.958/0.961, and 0.988/0.989 for HF, B3LYP, and BLYP (6-31G */6-31G* *), respectively.

  2. (9H-Fluoren-9-ylmethyl N-{(2R,3R,4S-4-hydroxy-2-[(2S,5R-2-isopropyl-5-methylcyclohexyloxy]-5-oxooxolan-3-yl}carbamate propan-2-ol 0.334-solvate

    Directory of Open Access Journals (Sweden)

    Graeme J. Gainsford

    2012-02-01

    Full Text Available The title compound, C29H35NO6.0.334C3H8O, a novel chiral N-(fluoren-9-ylmethyloxyxcarbonyl precursor, crystallizes with two independent carbamate (M molecules and propan-2-ol solvent molecules in the unit cell. Its crystal structure has been determined from barely adequate data obtained from a multi-fragment needle crystal. In the crystal, N—H...O hydrogen bonds link M molecules related by translation along the a axis into two independent chains. The ordered solvent molecule, having a partial occupancy of 0.334, is attached to one independent M molecule through O—H...O hydrogen bonds. The crystal packing exhibits weak intermolecular C—H...O interactions and voids of 270 Å3 filled with randomly disordered solvent molecules which were handled using the SQUEEZE methodology.

  3. 固相萃取-高效液相色谱法测定黄酒中氨基甲酸乙酯%Determination of Ethyl Carbamate in Yellow Rice Wine by Solid- phase Extraction Coupled with HPLC

    Institute of Scientific and Technical Information of China (English)

    诸葛庆; 李博斌; 江涛; 寿谦; 葛乐勇; 曾红艳

    2012-01-01

    建立一种反相高效液相色谱法测定黄酒中氨基甲酸乙酯的方法。样品经固相萃取柱净化后衍生,采用反相C18色谱柱XB—Cfsf4.6mm×250mm,5μm),以乙腈-0.02moL/L乙酸纳水溶液为流动相进行梯度洗脱,流速为lmL/min;设定荧光检测器中激发波长为233nm,发射波长为600nm,对黄酒中的氨基甲酸乙酯进行检测。结果表明,在50.0-250.0μg/L添加量范围内,平均回收率为92.9%,相对标准偏差为4.5%(n=6)。方法的检出限为10μg/L,线性范围为100~1500μg/L(R=0.9995),测定结果与标准气相色谱一质谱法基本相同。所建立的方法可以作为黄酒中氨基甲酸乙酯的检测方法。%A reverse phase HPLC method for the determination of ethyl carbamate in yellow rice wine had been developed. Wine samples were firstly pretreated by solid-phase extraction,ethyl carbamate was separated on a XB- CL8 (4.6mm×250 mm,5 μm) by using gradient elution (acetonitrile and 0.02 moL/L sodium acetate as the mobile phase) at a flow rate of lmL/min and detected by a fluorescence detector (kex=233 nm, hem=600 nm). At the spike levels of 50.0,100.0 and 250.0μg/L, the average recovery for ethyl carbamate was 92.9% with RSD as 4.5 % (n = 6), the detection limit was 10 μg/L, and the linear range was from 100-500μg/L(R=0.9995.The determination results by this method were almost the same as those by GCMS. Therefore, this method could be use to determine ethyl carbamate in yellow rice wine.

  4. 高效液相色谱直接进样法测定水中氨基甲酸酯%Determination carbamates in ambient water by direct injection -HPLC -FD

    Institute of Scientific and Technical Information of China (English)

    陈军; 卜伟; 程滢; 张宗祥

    2008-01-01

    采用直接进样-高效液相色谱-荧光检测,Waters Carbamate Analysis3.9×150 mm色谱柱,以水-甲醇-乙腈为流动相,激发波长为339nm,发射波长为445 nm定量测定水中的氨基甲酸酯.结果表明本方法的标准偏差在0.02-0.12 μg/L之间,变异系数在1.07%-7.24%之间,平均回收率在89.5%-100.5%之间,检出限在0.06-0.36 μg/L之间.

  5. Measurement of Ethyl Carbamate Content in Baijiu(Liquor) by SPE Coupled with GC-MS%SPE结合GC-MS法测定白酒中的氨基甲酸乙酯

    Institute of Scientific and Technical Information of China (English)

    李安军; 刘国英; 汤有宏; 张严; 高江婧; 姜利; 张培龙

    2014-01-01

    氨基甲酸乙酯(Ethyl carbamate,EC)是发酵食品和酒精饮料制造过程伴随产生的一种具有潜在致癌性的物质.采取固相萃取结合GC-MS以氨基甲酸丙酯(PC)为内标的方法测定白酒中EC的含量,并完善优化实验条件.结果表明,该方法平均回收率为90.52%,相对标准偏差(RSD)为4.97%,检出限2.8 μg/L.适用于白酒中EC的日常分析检测.

  6. 高效液相色谱直接进样法测定水中氨基甲酸酯%To Directly Detect Carbamate in Ambient Water by HPLC

    Institute of Scientific and Technical Information of China (English)

    程滢; 陈军; 薛锐

    2007-01-01

    采用高效液相色谱法测定水中氨基甲酸酯,用Waters Carbamate Analysis3.9×150mm色谱柱,以水-甲醇-乙腈为流动相,用激发波长为339nm,发射波长为445nm的荧光检测器定量测定水中氨基甲酸酯的含量,结果表明本方法的标准偏差在0.02~0.12μg/L之间,变异系数在1.07%~7.24%之间,平均回收率在89.5%~100.5%之间.

  7. 2010年杭州市蔬菜有机磷和氨基甲酸酯农药残留状况分析%Analysis of organophosphorus and carbamate pesticide residues in vegetables collected from Hangzhou in 2010

    Institute of Scientific and Technical Information of China (English)

    何良兴; 张瓅文; 李燕

    2011-01-01

    目的:了解杭州市蔬菜农药残留情况,为蔬菜质量安全的监管和控制工作提供科学依据.方法:采集蔬菜样品446577批次,测定有机磷和氨基甲酸酯农药残留量,并对结果进行分析总结.结果:蔬菜年均农药超标率为0.09%,残留农药以有机磷为主,不同品种蔬菜的超标率与超标农药类型都不同,杭州本地与外地蔬菜农药超标率没有显著不同.结论:杭州市蔬菜农药残留水平较低,质量安全状况良好,但禁用农药还需要进一步加强监管.%Objective: To investigate the conditions of organophosphorus and carbamate pesticide residues in vegetables in Hangzhou in order to provide the basis for surveillance and control of vegetables safety. Methods: The total 446,577 samples of vegetables were collected and their residues of organophosphorus and carbamate were measured. At last, the results were analysised and summaried. Results: The disqualification rate of vegetables is 0.09%. The organophosphorus is the main pesticide residues. The disqualification rate and the type of pesticide residues varies in different kinds of vegetables. There's no difference in the disqualification rate of vegetables between Hangzhou and other places. Conclusion: The level of pesticide residues is low,and vegetable quality of Hangzhou is good, but supervision and administration on the forbidden pesticides should be strengthened.

  8. Rapid Determination of Organic Phosphorus and Carbamate Pesticides in Samples%样品中有机磷与氨基甲酸酯类农药快速检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    卫海燕; 邵华

    2011-01-01

    目的 建立现场快速筛选区分有机磷农药和氨基甲酸酯类农药的方法.方法 在薄层色谱原理基础上,利用毛细管效应制备微色谱柱检测仪,检测2类农药.结果 该方法可以对有机磷农药和氨基甲酸酯类农药作出快速的定性分析,且最低检出量可达到10 μg.结论 该法操作简便,高效,重现性好,且试剂用量少,是批量农药样品定性检测和突发农药中毒事件现场快速筛选的一种新方法.%[Objective]To establish the method for rapid filtering organophosphorus pesticides and carbamate pesticides.[Methods]Based on the principle of thin-layer chromatography, the micro-column detector was prepared by using capillary effect, and was used to detect 2 kinds of pesticides.[Results]The method could make qualitative and quantitative analysis of organophosphorus peaticides and carbamate pesticides, and the minimum detection limit was 10 μg.[Conclusion]The method is simple, efficient, reproducible, with less reagent consumption, and it is a new method for qualitative detection of bulk samples of pesticides and rapid pesticide poisoning filtering in emergency incident.

  9. Validation and use of a fast sample preparation method and liquid chromatography-tandem mass spectrometry in analysis of ultra-trace levels of 98 organophosphorus pesticide and carbamate residues in a total diet study involving diversified food types.

    Science.gov (United States)

    Chung, Stephen W C; Chan, Benny T P

    2010-07-16

    This paper reports a comprehensive sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, identification and quantitation of 73 pesticides and their related products, a total of 98 analytes, belonging to organophosphorus pesticides (OPPs) and carbamates, in foods. The proposed method makes use of a modified QuEChERS (quick, easy, cheap, effective, rigged, and safe) procedure that combines isolation of the pesticides and sample clean-up in a single step. Analysis is performed by liquid chromatography-electrospray ionization-tandem mass spectrometry operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Two main fragment ions for each pesticide were obtained to achieve the identification according to the SANCO guidelines 10684/2009. The method was validated with various food samples, including edible oil, meat, egg, cheese, chocolate, coffee, rice, tree nuts, citric fruits, vegetables, etc. No significant matrix effect was observed for tested pesticides, therefore, matrix-matched calibration was not necessary. Calibration curves were linear and covered from 1 to 20 microg L(-1) for all compounds studied. The average recoveries, measured at 10 microg kg(-1), were in the range 70-120% for all of the compounds tested with relative standard deviations below 20%, while a value of 10 microg kg(-1) has been established as the method limit of quantitation (MLOQ) for all target analytes. Similar trueness and precision results were also obtained for spiking at 200 microg kg(-1). Expanded uncertainty values were in the range 21-27% while the HorRat ratios were below 1. The method has been successfully applied to the analysis of 700 food samples in the course of a baseline monitoring study of OPPs and carbamates. PMID:20557892

  10. Folic Acid

    Science.gov (United States)

    ... found naturally in some foods, including leafy vegetables, citrus fruits, beans (legumes), and whole grains. Folic acid ... mcg of folic acid every day for good health. But older adults need to be sure they ...

  11. Novel PdCI 2 (RuCI 3)/ZrO2SO3 Catalysts for Synthesis of Carbamates by Oxidative Carbonylation of Amines%一种胺氧化羰化制氨基甲酸酯新催化剂体系

    Institute of Scientific and Technical Information of China (English)

    石峰; 司马天龙; 邓友全

    2000-01-01

    Novel combined PdC12 (RuCl3) with ZrO2-SO3 catalysts were developed for the synthesis of carbamates by oxidative carbonylation of aliphatic and aromatic amines. At 170 ℃ and 4.0 MPa, oxidative carbonylation of aromatic amines to the corresponding carbamates over this catalyst system could be proceeded with a high conversion and selectivity. Especially when β-naphthylamine was used as the substrate, 100% conversion and 95% selectivity were obtained in only 15 min. The catalytic performance of PdCl2/ZrO2-SO3 was better than that of RuCl3/ZrO2-SO3 for such oxidative carbonylation reaction.Possible role of ZrO2-SO3 as co-catalyst was also conjectured.

  12. Chromatographic method for determination of the free amino acid content of chamomile flowers

    Directory of Open Access Journals (Sweden)

    Xiaoli Ma

    2015-01-01

    Full Text Available Objective: To determine the free amino acid contents of chamomile flowers using reverse-phase high-performance column chromatography preceded by pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC, and to determine the reliability of this method. Materials and Methods: Derivatization with reconstituted AQC was used to prepare the samples and standards for injection into the chromatography column. The peaks were analyzed by fluorescence detection (λ excitation, 250 nm; λ emission, 395 nm. Results: Alanine, proline, and leucine were the most abundant amino acids, whereas tyrosine and methionine were the least abundant. The linearity of the method was found to be good with amino acid concentrations of 0.012-0.36 μM. The precision was 0.05-1.36%; average recovery, 91.12-129.41%; and limit of detection, 0.006-0.058 μM. Conclusion: The method is reliable for determining the free amino acid content of different types of chamomile flowers.

  13. Influence of phenolic compounds on the growth and arginine deiminase system in a wine lactic acid bacterium

    Directory of Open Access Journals (Sweden)

    María R. Alberto

    2012-03-01

    Full Text Available The influence of seven phenolic compounds, normally present in wine, on the growth and arginine deiminase system (ADI of Lactobacillus hilgardii X1B, a wine lactic acid bacterium, was established. This system provides energy for bacterial growth and produces citrulline that reacts with ethanol forming the carcinogen ethyl carbamate (EC, found in some wines. The influence of phenolic compounds on bacterial growth was compound dependent. Growth and final pH values increased in presence of arginine. Arginine consumption decreased in presence of protocatechuic and gallic acids (31 and 17%, respectively and increased in presence of quercetin, rutin, catechin and the caffeic and vanillic phenolic acids (between 10 and 13%, respectively. ADI enzyme activities varied in presence of phenolic compounds. Rutin, quercetin and caffeic and vanillic acids stimulated the enzyme arginine deiminase about 37-40%. Amounts of 200 mg/L gallic and protocatechuic acids inhibited the arginine deiminase enzyme between 53 and 100%, respectively. Ornithine transcarbamylase activity was not modified at all concentrations of phenolic compounds. As gallic and protocatechuic acids inhibited the arginine deiminase enzyme that produces citrulline, precursor of EC, these results are important considering the formation of toxic compounds.

  14. Ibotenic acid and thioibotenic acid

    DEFF Research Database (Denmark)

    Hermit, Mette B; Greenwood, Jeremy R; Nielsen, Birgitte;

    2004-01-01

    In this study, we have determined and compared the pharmacological profiles of ibotenic acid and its isothiazole analogue thioibotenic acid at native rat ionotropic glutamate (iGlu) receptors and at recombinant rat metabotropic glutamate (mGlu) receptors expressed in mammalian cell lines....... Thioibotenic acid has a distinct pharmacological profile at group III mGlu receptors compared with the closely structurally related ibotenic acid; the former is a potent (low microm) agonist, whereas the latter is inactive. By comparing the conformational energy profiles of ibotenic and thioibotenic acid with...... the conformations preferred by the ligands upon docking to mGlu1 and models of the other mGlu subtypes, we propose that unlike other subtypes, group III mGlu receptor binding sites require a ligand conformation at an energy level which is prohibitively expensive for ibotenic acid, but not for...

  15. [Gastric Acid].

    Science.gov (United States)

    Ruíz Chávez, R

    1996-01-01

    Gastric acid, a product of parietal cells secretion, full fills multiple biological roles which are absolutely necessary to keep corporal homeostasis. The production of the acid depends upon an effector cellular process represented in the first step by histamine, acetilcholine and gastrin, first messengers of the process. These interact with specific receptors than in sequence activate second messengers -cAMP and the calcium-calmodulin system- which afterwards activate a kinase. An specific protein is then phosphorilated by this enzyme, being the crucial factor that starts the production of acid. Finally, a proton bomb, extrudes the acid towards the gastric lumen. The secretion process mentioned above, is progressive lyactivated in three steps, two of which are stimulators -cephalic and gastric phases- and the other one inhibitor or intestinal phase. These stages are started by mental and neurological phenomena -thought, sight, smell or memory-; by food, drugs or other ingested substances; and by products of digestion. Changes in regulation of acid secretion, in the structure of gastro-duodenal mucosal barrier by a wide spectrum of factors and agents including food, drugs and H. pylori, are the basis of acid-peptic disease, entity in which gastric acid plays a fundamental role. From the therapeutic point of view, so at the theoretical as at the practical levels, t is possible to interfere with the secretion of acid by neutralization of some of the steps of the effector cellular process. An adequate knowledge of the basics related to gastric acid, allows to create strategies for the clinical handling of associated pathology, specifically in relation to peptic acid disease in all of the known clinical forms. PMID:12165790

  16. Biocatalytic ammonolysis of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester: preparation of an intermediate to the dipeptidyl peptidase IV inhibitor Saxagliptin.

    Science.gov (United States)

    Gill, Iqbal; Patel, Ramesh

    2006-02-01

    An efficient biocatalytic method has been developed for the conversion of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester (1) into the corresponding amide (5S)-5-aminocarbonyl-4,5-dihydro-1H-pyrrole-1-carboxylic acid, 1-(1,1-dimethylethyl)ester (2), which is a critical intermediate in the synthesis of the dipeptidyl peptidase IV (DPP4) inhibitor Saxagliptin (3). Candida antartica lipase B mediates ammonolysis of the ester with ammonium carbamate as ammonia donor to yield up to 71% of the amide. The inclusion of Ascarite and calcium chloride as adsorbents for carbon dioxide and ethanol byproducts, respectively, increases the yield to 98%, thereby offering an efficient and practical alternative to chemical routes which yield 57-64%. PMID:16257208

  17. Folic acid

    Science.gov (United States)

    ... include leafy vegetables (such as spinach, broccoli, and lettuce), okra, asparagus, fruits (such as bananas, melons, and ... Pyrimethamine (Daraprim)Pyrimethamine (Daraprim) is used to treat parasite infections. Folic acid might decrease the effectiveness of ...

  18. Folic Acid

    Medline Plus

    Full Text Available ... March of Dimes Premature Birth Report Card Grades Cities, Counties; Focuses on Racial and Ethnic Disparities March ... your baby. Learn how you can get the right amout of folic acid before and during pregnancy ...

  19. ACID RAIN

    Science.gov (United States)

    Acid precipitation has become one of the major environmental problems of this decade. It is a challenge to scientists throughout the world. Researchers from such diverse disciplines as plant pathology, soil science, bacteriology, meteorology and engineering are investigating diff...

  20. Folic Acid

    Medline Plus

    Full Text Available ... Just a moment, please. You've saved this page It's been added to your dashboard . Folic acid ... Map Premature birth report card Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & fitness ...

  1. Folic Acid

    Medline Plus

    Full Text Available ... Folic acid Description | Related videos | Most played video E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  2. Development of [125I]RB104, a potent inhibitor of neutral endopeptidase 24.11, and its use in detecting nanogram quantities of the enzyme by "inhibitor gel electrophoresis".

    OpenAIRE

    Fournié-Zaluski, M. C.; Soleilhac, J. M.; Turcaud, S; Laï-Kuen, R; Crine, P; Beaumont, A.; Roques, B P

    1992-01-01

    Neutral endopeptidase 24.11, also known as the common acute lymphoblastic leukemia antigen, is a zinc metallopeptidase involved in the inactivation of biologically active peptides, such as the enkephalins and atrial natriuretic peptide. The highly potent radiolabeled inhibitor 2-((3-[125I]iodo-4-hydroxy)phenylmethyl)-4-N-[3-(hydroxyamino-3-oxo-1- phenylmethyl)propyl]amino-4-oxobutanoic acid ([125I]RB104; Ki = 30 pM) has been developed for the enzyme. [125I]RB104 is highly specific, its Ki for...

  3. 4-Phenylureido/thioureido-substituted 2,2-dimethylchroman analogs of cromakalim bearing a bulky 'carbamate' moiety at the 6-position as potent inhibitors of glucose-sensitive insulin secretion.

    Science.gov (United States)

    Pirotte, Bernard; Florence, Xavier; Goffin, Eric; Medeiros, Marlen Borges; de Tullio, Pascal; Lebrun, Philippe

    2016-10-01

    The synthesis of 2,2-dimethylchromans bearing a 3/4-chloro/cyano-substituted phenylureido or phenylthioureido moiety at the 4-position and an alkoxycarbonylamino ('carbamate') group at the 6-position is described. These new analogs of the potassium channel opener (±)-cromakalim were further tested on rat pancreatic islets as putative inhibitors of insulin release and on rat aorta rings as putative vasorelaxants. All compounds inhibited insulin secretion and induced a myorelaxant activity. Compound 14o [R/S-N-3-cyanophenyl-N'-(6-tert-butoxycarbonylamino-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)urea; BPDZ 711] emerged as the most potent inhibitor of the glucose-sensitive insulin releasing process (IC50 = 0.24 μM) and displayed selectivity towards the pancreatic endocrine tissue. Radioisotopic, fluorimetric and pharmacological investigations were performed on rat pancreatic islet and rat vascular smooth muscle cells in order to decipher its mechanism of action. Our findings suggest that the mechanism of action of 14o is rather unspecific. The compound behaves as a KATP channel opener, a Ca(2+) entry blocker, and promotes an intracellular calcium translocation. PMID:27267004

  4. FT-IR, NBO, HOMO-LUMO, MEP analysis and molecular docking study of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl)phenyl]amino}[(methoxycarbonyl) imino]methyl)carbamate

    Science.gov (United States)

    Panicker, C. Yohannan; Varghese, Hema Tresa; Narayana, B.; Divya, K.; Sarojini, B. K.; War, Javeed Ahmad; Van Alsenoy, C.; Fun, H. K.

    2015-09-01

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl) phenyl]amino} [(methoxycarbonyl)imino]methyl)carbamate have been investigated using HF and DFT levels of calculations. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential study was also performed. The first and second hyperpolarizability was calculated in order to find its role in nonlinear optics. Molecular docking studies are also reported. Prediction of Activity Spectra analysis of the title compound predicts anthelmintic and antiparasitic activity as the most probable activity with Pa (probability to be active) value of 0.808 and 0.797, respectively. Molecular docking studies show that both the phenyl groups and the carbonyl oxygens of the molecule are crucial for bonding and these results draw us to the conclusion that the compound might exhibit pteridine reductase inhibitory activity.

  5. Investigation on the Formation of Ethyl Carbamate in Grape Wine and Wine Quality Control%葡萄酒中氨基甲酸乙酯形成及质量控制

    Institute of Scientific and Technical Information of China (English)

    梁新红; 孙俊良; 曾洁

    2009-01-01

    氨基甲酸乙酯(Ethyl Carbamate,EC)是一种基因致癌物,葡萄酒及其他酒精饮料中含有微量的氨基甲酸乙酯.葡萄酒中氨基甲酸乙酯主要由酵母降解精氨酸产生的尿素和苹果酸-乳酸茵降解精氨酸产生的瓜氨酸与乙醇自发反应产生.阐述了氨基甲酸乙酯的致癌作用、葡萄酒中氨基甲酸乙酯的形成途径及影响其形成的因素;探讨了降低葡萄酒中氨基甲酸乙酯的措施,为我国葡萄酒生产中降低氨基甲酸乙酯含量提供了理论依据.

  6. Vibrational (FT-IR, FT-Raman) and UV-Visible spectroscopic studies, HOMO-LUMO, NBO, NLO and MEP analysis of Benzyl (imino (1H-pyrazol-1-yl) methyl) carbamate using DFT calculaions

    Science.gov (United States)

    Shankar Rao, Y. B.; Prasad, M. V. S.; Udaya Sri, N.; Veeraiah, V.

    2016-03-01

    This paper contains a combined experimental and theoretical study of vibrational and electronic properties of Benzyl(imino(1H-pyrazol-1-yl)methyl)carbamate (BPMC) molecule. The FT-IR and FT-Raman spectra of the title molecule in solid phase were recorded in the region 4000-400 cm-1 and 4000-50 cm-1, respectively. The UV absorption spectrum of the studied compound dissolved in ethanol was recorded in the range of 180-400 nm. The molecular geometries calculated using density functional theory (DFT) was compared with available experimental data. The vibrational spectra calculated at the B3LYP/6-31G(d,p) level were compared with the experimental spectra and assignment to each vibrational frequency was assigned on the basis of potential energy distribution (PED). The calculated electronic and nonlinear optical properties of the title molecule were reported. Furthermore, the thermodynamic properties of the molecule were discussed.

  7. An Important Role for N-Acylethanolamine Acid Amidase in the Complete Freund's Adjuvant Rat Model of Arthritis.

    Science.gov (United States)

    Bonezzi, F T; Sasso, O; Pontis, S; Realini, N; Romeo, E; Ponzano, S; Nuzzi, A; Fiasella, A; Bertozzi, F; Piomelli, D

    2016-03-01

    The endogenous lipid amides, palmitoylethanolamide (PEA) and oleoylethanolamide (OEA), exert marked antinociceptive and anti-inflammatory effects in animal models by engaging nuclear peroxisome proliferator-activated receptor-α. PEA and OEA are produced by macrophages and other host-defense cells and are deactivated by the cysteine amidase, N-acylethanolamine acid amidase (NAAA), which is highly expressed in macrophages and B-lymphocytes. In the present study, we examined whether a) NAAA might be involved in the inflammatory reaction triggered by injection of complete Freund's adjuvant (CFA) into the rat paw and b) administration of 4-cyclohexylbutyl-N-[(S)-2-oxoazetidin-3-yl]-carbamate (ARN726), a novel systemically active NAAA inhibitor, attenuates such reaction. Injection of CFA into the paw produced local edema and heat hyperalgesia, which were accompanied by decreased PEA and OEA content (assessed by liquid chromatography/mass spectrometry) and increased NAAA levels (assessed by Western blot and ex vivo enzyme activity measurements) in paw tissue. Administration of undec-10-ynyl-N-[(3S)-2-oxoazetidin-3-yl] carbamate (ARN14686), a NAAA-preferring activity-based probe, revealed that NAAA was catalytically active in CFA-treated paws. Administration of ARN726 reduced NAAA activity and restored PEA and OEA levels in inflamed tissues, and significantly decreased CFA-induced inflammatory symptoms, including pus production and myeloperoxidase activity. The results confirm the usefulness of ARN726 as a probe to investigate the functions of NAAA in health and disease and suggest that this enzyme may provide a new molecular target for the treatment of arthritis. PMID:26769918

  8. 2-(tert-Butoxycarbonylamino-6-(1,3-dioxo-1H-2,3-dihydrobenzo[de]isoquinolin-2-ylhexanoic acid

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2010-05-01

    Full Text Available In the title naphthalimide derivative, C23H26N2O6, the 1,8-naphthalimide system is essentially planar [maximum deviation = 0.0456 (16 Å]. A characteristic pattern of alternating long and short C—C bond lengths is observed in the 1,8-naphthalimide unit. The mean planes through the methyl carbamate and acetic acid groups form dihedral angles of 42.30 (9 and 61.59 (9°, respectively, with the 1,8-naphthalimide plane. In the crystal structure, intermolecular O—H...O and C—H...O hydrogen bonds link neighbouring molecules, forming R22(9 hydrogen-bond ring motifs. These rings are further interconnected by intermolecular N—H...O and C—H...O hydrogen bonds into a three-dimensional supramolecular network.

  9. Okadaic acid

    DEFF Research Database (Denmark)

    Danielsen, E Michael; Hansen, Gert H; Severinsen, Mai C K

    2014-01-01

    Okadaic acid (OA) is a polyether fatty acid produced by marine dinoflagellates and the causative agent of diarrhetic shellfish poisoning. The effect of OA on apical endocytosis in the small intestine was studied in organ cultured porcine mucosal explants. Within 0.5-1 h of culture, the toxin caused...... endosomes (TWEEs) occurred unimpeded in the presence of OA, FM condensed in larger subapical structures by 1 h, implying a perturbed endosomal trafficking/maturation. The fluorescent lysosomotropic agent Lysotracker revealed induction of large lysosomal structures by OA. Endocytosis from the brush border...

  10. Perfluorooctanoic acid

    NARCIS (Netherlands)

    P. de Voogt

    2014-01-01

    Perfluorooctanoic acid (PFOA, 335-67-1) is used in fluoropolymer production and firefighting foams and persists in the environment. Human exposure to PFOA is mostly through the diet. PFOA primarily affects the liver and can cause developmental and reproductive toxic effects in test animals.

  11. Ascorbic Acid

    Science.gov (United States)

    Cevi-Bid® ... If you become pregnant while taking ascorbic acid, call your doctor. ... In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call ...

  12. Stearic Acid

    Science.gov (United States)

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) is presented for the chemical, stearic acid. The profile lists the chemical's physical and harmful characteristics, exposure limits, and symptoms of major exposure, for the benefit of teachers and students, who use the chemical in the laboratory.

  13. Mefenamic Acid

    Science.gov (United States)

    Mefenamic acid comes as a capsule to take by mouth. It is usually taken with food every 6 hours as needed for up to 1 week. Follow ... pain vomit that is bloody or looks like coffee grounds black, tarry, or bloody stools slowed breathing ...

  14. 磷酸-氨基甲酸酯化变性淀粉对粘胶纱低温上浆性能的影响%Effects of phosphate-carbamate starch on the sizing properties of viscose yarns at low temperature

    Institute of Scientific and Technical Information of China (English)

    刘志军

    2013-01-01

    测试了磷酸-氨基甲酸酯化变性淀粉的透明度、粘度、粘度热稳定性以及对粘胶纱的粘附性能,研究了该淀粉在热敏感型粘胶纱低温上浆中应用的可行性.结果表明:淀粉经复合酯化变性后能改善淀粉糊的透明度,提高淀粉浆液的抗凝胶性能,浆液在60~80℃时仍具有良好的粘度稳定性;能显著提高对粘胶纱的粘附性能,浆液温度的降低对粘附力没有明显影响,能够用于粘胶经纱低温上浆.%The transparency, viscosity, viscosity thermal stability of the phosphate-carbamate starch and the adhesion to viscose fiber were measured. The feasibility of application of starch in sizing heat-sensitive viscose yarns at low temperature was discussed. The results showed that the modification was favorable to improve the transparency and anti-gelling behavior of the starch paste. Phosphate-carbamate starch paste could also keep good viscosity stability at 60~80 ℃. The adhesion of phosphate-carbamate starch for viscose fiber could be significantly improved and the reduction of the temperature of size liquid had little effect on the adhesion. The modified starch could meet the requirements for sizing viscose yarns under lower temperature.

  15. 液相色谱-串联质谱法测定植物源性食品中16种氨基甲酸酯类农药及其代谢物%Determination of 16 carbamate pesticides and metabolite residues in plant-derived foodstuffs by high pressure liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    王敬; 陈瑞春; 郭春海; 窦彩云

    2013-01-01

    目的:建立液相色谱-串联质谱法测定植物源性食品中16种氨基甲酸酯类农药及其代谢物(涕灭威、涕灭威亚砜、涕灭威砜、灭害威、恶虫威、甲萘威、克百威、乙霉威、仲丁威、茚虫威、异丙威、灭多威、速灭威、杀线威、抗蚜威和残杀威)残留量的方法。方法样品用0.1%冰醋酸-乙腈提取,提取液经过滤、浓缩后用石墨化炭黑/氨基固相萃取柱净化,采用多反应监测(multi-reaction monitoring, MRM)正离子扫描模式进行准确的定性和定量分析。结果16种氨基甲酸酯类农药在5~500 ng/mL浓度范围内均呈良好线性。16种农药在苹果、菠菜、山药、大米、大豆和生姜6种基质中的检出限和定量下限为2.0µg/kg和5.0µg/kg,在低、中、高3个水平的加标回收率为71.0%~108.0%之间, RSDs (relative standard deviations)为2.03%~11.30%。结论该方法简单快速,其灵敏度、准确度和精密度均能满足农药残留分析的要求。%Objective To establish a high pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for determination 16 kinds of carbamate pesticides and their metabolites (aldicarb, al-dicarb-sulfoxide, aldicarb-sulfone, aminocarb, bendicarb, carbaryl, carbofuran, diethofencarb, fenobucarb, in-doxacarb, isoprocarb, methomyl, metolcarb, oxamyl, pirimicarb and propoxur) in plant-derived foodstuffs. Methods Samples were extracted with 0.1%formic acid-acetonitrile solution. After concentrated, the solution was cleaned up with solid-phase extraction (SPE) column of envi-Carb/NH2, the mode of multi-reaction moni-toring positive ion scanning was adopted for both the quantitative and qualitative analyses. Results Calibra-tion curves showed a good linearity over the range of 5~500 ng/mL. The limits of detection (LOD) were 2.0 µg/kg and the limits of quantification (LOQ) were 5.0 µg/kg for all the 16 pesticides spiked in apple, spinach, Chinese yam, rice, soybean and ginger

  16. L'acétylcholinestérase des poissons, cible des organophosphorés et des carbamates. Caractérisation du gène et des formes moléculaires de l'enzyme chez Danio rerio. Effets des anticholinestérasiques

    OpenAIRE

    Bertrand, C.; Cousin, X; Haubruge, E.; TOUTANT J. P.; Chatonnet, A

    1998-01-01

    L'acétylcholinestérase (AChE, EC 3.1.1.7) est une enzyme indispensable de la transmission synaptique cholinergique. Son inhibition par les organophosphorés et les carbamates est à la base de certains traitements insecticides et nématicides utilisés en agriculture. Les faunes sauvage (en particulier les poissons) et domestique sont exposées aux résidus des traitements anticholinestérasiques. La mesure de l'inhibition de l'activité AChE chez ces espèces est un marqueur fiable de l'exposition. C...

  17. Detection of 20 carbamate pesticides in asparagus by ultra performance liquid chromatography-electrospray ionization-mass spectrometry-mass spectrometry%超高效液相色谱-电喷雾串联四极杆质谱法检测芦笋中20种氨基甲酸酯类农药残留

    Institute of Scientific and Technical Information of China (English)

    赵晓琳; 霍乃蕊; 花锦; 宋欢

    2015-01-01

    目的:建立芦笋及其罐头制品中20种氨基甲酸酯类农药残留的定性定量分析方法。方法采用改进的 QuEchERS 法提取和净化,利用超高效液相色谱-电喷雾串联四极杆质谱仪,在多反应监测正离子扫描模式下对样品进行添加回收率试验。结果分别对绿芦笋、白芦笋、绿芦笋罐头、白芦笋罐头4种空白基质添加0.005~0.050 mg/kg农药样品进行回收率试验,回收率为62.44%~85.99%,定量限均为0.005 mg/kg, RSD均小于9%。结论该方法简单快速,灵敏度高,能够同时满足芦笋及其罐头制品中20种氨基甲酸酯类农药残留的检测要求。%Objective To establish an ultra performance liquid chromatography-electrospray ionization-mass spectrometry-mass spectrometry method for detecting of 20 kinds of carbamate pesticides in asparagus and asparagus products. Methods Samples were extracted by modified QuEchERS method, and the mode of multi-reaction monitoring positive ion scanning was applied for analysis by ultra high performance liquid chromatography-electrospray tandem quadrupole mass spectrometer. Results The blank matrixes (green asparagus, white asparagus, canned white asparagus, canned white asparagus) were added 0.005~0.050 mg/kg carbamate pesticides separately and recovery tests were performed. Results demonstrated that the recovery rates were in the range of 62.44%~85.99% and the limits of quantification were 0.005 mg/kg for all the 20 carbamate pesticides tested with the relative standard deviations (RSDs) below 9%. Conclusion The method, not only simple and fast but also high sensitive, can satisfy the international detection requirement for 20 carbamate pesticides residue in asparagus product simultaneously.

  18. 顶空液相微萃取/气相色谱-质谱检测葡萄酒中的氨基甲酸乙酯%Applied the method of headspace liquid-phase micro-extraction coupled with gas chromatography-mass spectro metry to the determination of ethyl carbamate in wines

    Institute of Scientific and Technical Information of China (English)

    姜自军; 阎雪; 单纪平; 徐刚; 慈慧

    2013-01-01

    建立了顶空液相微萃取/气相色谱仪-质谱联用测定葡萄酒中的氨基甲酸乙酯的方法。对影响萃取效率的实验条件进行了优化。采用Rtx-Wax毛细管柱进行检测,以癸烷为萃取溶剂,在60℃、搅拌速度为200r/min条件下对1mL葡萄酒样品萃取30min。该方法对氨基甲酸乙酯的富集倍数为62;在100~1600µg/L的范围内线性关系良好。相关系数为0.9999;氨基甲酸乙酯的检出限为1µg/L(S/N=3)。实际酒样的加标回收率为81.0%~103.1%。%Headspace liquid-phase micro-extraction (HS-LPEM) coupled with gas chromatography-mass spectrometry (GC-MS) was used to determine the ethyl carbamate of wines. Some main experimental parameters that affect the extraction efficiency were optimized. Decane was selected as extraction solvent. The extraction was carried out at 60℃in a 2mL vial filled with 1mL of sample solution at a stirring rate of 500r/min for 30min. The enrichment factors for the ethyl carbamate was 62. The linear range for the quantification of the ethyl carbamate was 100~1600 µg/L(R2=0.9999) . The limit of detection was 1µg/L(S/N=3)for the ethyl carbamate. Recovery was 81.0%~103.1%.

  19. UPLC -MS/MS determination of carbamate pesticides in traditional Chinese medicine%超高效液相色谱-串联质谱法测定中草药中氨基甲酸酯类农药残留量

    Institute of Scientific and Technical Information of China (English)

    李娜; 刘磊; 邵辉; 李辉; 张玉婷; 宋海菲; 郭永泽

    2011-01-01

    目的:结合固相萃取技术,克服了中草药样品中复杂的基质干扰问题,建立超高效液相色谱-串联质谱( UPLC - MS/MS)法检测中药材中15种氨基甲酸酯类杀虫剂的残留量.方法:样品中残留的农药经乙腈提取,PSA固相萃取柱净化后,采用UPLC - MS/MS法进行测定.结果:15种农药在其各自的浓度范围内,线性关系良好,相关系数在0.995 ~0.999之间.在定量限(LOQ)、5倍定量限和10倍定量限3个添加浓度水平,平均加标回收率在61.8% ~98.1%之间;RSD在1.8% ~ 14.8%之间.结论:该方法操作简便,净化效果好,灵敏度高,可为中药材中氨基甲酸酯类杀虫剂污染状况调查提供检测方法支持.%Objective:An ultra performance liquid chromatography - tandem mass spectrometric method was developed for the determination of 15 carbamate pesticides in traditional Chinese medicine. Method:Pesticides were extracted with acetonitrile,cleaned up by PSA solid phase extraction column,and then analyzed by UPLC -MS/MS. Result:The standard calibration curves for 15 carbamate pesticides showed high correlation coefficient (0.995 -0. 999) over their respective concentration range. The average recovery of 15 carbamate pesticides at the three fortification levels ( LOQ,5 LOQ and 10 LOQ) was between 61. 8% and 98. 1% with the relative standard deviation between 1. 8% and 14. 8%. Conclusion:It was indicated that the method developed in this study is easier,more sensitive and has a better purification effect. So,this method can be further applied to investigate the contamination status of traditional Chinese medicine by the carbamate pesticides.

  20. PSA分散固相萃取液相色谱柱后衍生荧光法测定蔬菜和水果中的13种氨基甲酸酯%Study on determination of thirteen carbamate pesticides in vegetables and fruits by HPLC with post-column derivatization and fluorescence detection after PSA dispersive solid-phase extraction cleanup

    Institute of Scientific and Technical Information of China (English)

    于彦彬; 谭丕功; 曲璐璐; 王学松

    2009-01-01

    建立了PSA分散固相萃取净化, 液相色谱柱后衍生荧光法测定蔬菜和水果中13种氨基甲酸酯农药的分析方法. 在建立的测定条件下, 13种氨基甲酸酯的含量与峰面积之间成线性关系, 相关系数大于0.994, 保留时间的相对标准偏差在0.03%~0.22%之间, 检测下限在2.00~2.28 μg/kg范围内. 西瓜、杏、茄子及胡萝卜中13种氨基甲酸酯的平均回收率在71.7%~110%之间, 相对标准偏差在0.68%~15%之间, 分析结果优于氨基柱固相萃取法.%Determination of thirteen carbamate pesticides residues in vegetables and fruits by HPLC with PSA dispersive solid-phase extraction cleanup and post-column derivatization fluorescence detection is developed. Under the optimal determination conditions, the detection limits of thirteen carbamate pesticides are in the range of 2.00~2.28 jug/kg. There is a good linear relationship in the content range of determination. The correlation coefficients of thirteen carbamate pesticides are more than 0.99. The relative standard deviations of retention time are in the range of 0.03%~0.22% . It is simpler in sample handling by PSA dispersive solid-phase extraction than by NH2 column solid-phase extraction. There are little interference in matrix, and high quality results are obtained. The spiked average recoveries of thirteen carbamate pesticide residues ranged from 71.7%~110% with RSDs of 0.68%~15% for watermelon, apricot, eggplant and carrot, The results are very satisfactory.

  1. 葡萄酒酵母car1基因表达量与EC含量相关性的研究%Study on correlation between the expression of car1 gene of different Saccharomyces cerevisiae and the content of carbamate ethgl in wine

    Institute of Scientific and Technical Information of China (English)

    魏玉洁; 付方圆; 武顺; 邹弯; 薛洁; 闫寅卓; 武运

    2015-01-01

    酿酒酵母(Saccharomyces cerevisiae)代谢精氨酸产生尿素对葡萄酒中氨基甲酸乙酯(carbamate ethyl,EC)含量的影响非常重要.利用实时荧光PCR技术,比较分析了18种酿酒酵母的发酵性能以及发酵期间酵母car1基因的表达活性与精氨酸、EC含量间的关系,结果表明:发酵期间,酵母car1基因的表达量均呈现先增加后降低的趋势,与发酵液中的精氨酸呈负相关关系,相关系数在0.9903~0.9977;而与EC含量呈现正相关关系,相关系数在0.6249~0.995 8之间;不同酵母car1基因的相对表达量存在显著差异,筛选精氨酸酶活力低的酵母菌株可以有效降低葡萄酒中的EC含量.%Urea produced by arginine metabolites from Saccharomyces cerevisiae has very important effect on the content of ethyl carbamate in wine.In this paper,the fermentation performance of 18 S.cerevisiae strains and the correlation between the expression level of car1 gene and the content of EC and arginine were analyzed.Real-time fluorescence PCR showed that the expression of car1 gene increased at the beginning of fermentation and decreased two days after fermentation.The expression level of car1 gene was significantly negatively related with the content of arginine with the correlation coefficient between 0.990 3 ~ 0.997 7,while it was positively related with the content of carbamate ethyl with the correlation coefficient between 0.624 9 ~ 0.995 8,which was obviously different between different yeasts.Selection of S.cerevisiae strains containing arginase with low activity could effectively reduce the content of Ethyl carbamate in wine.

  2. DETERMINATION OF CARBAMATE PESTICIDE RESIDUES IN WHEAT USING MATRIX SOLID-PHASE DISPERSION EXTRACTION AND LIQUID CHROMATOGRAPHY%基质固相分散萃取-液相色谱法测定小麦中多种氨基甲酸酯农药残留的研究

    Institute of Scientific and Technical Information of China (English)

    吴丽华; 田忙雀; 杨勤元

    2011-01-01

    研究了C18基质固相分散萃取(MSPDE),高效液相色谱-柱后衍生-荧光检测器测定小麦中6种氨基甲酸酯农药的方法.通过对色谱条件、基质固相分散材料的选择及其与样品的比例、洗脱条件以及加标回收率进行试验,建立和优化了小麦中6种氨基甲酸酯农药的MSPDE-HPLC-FLD多残留分析方法.结果显示,该方法对小麦样品中6种氨基甲酸酯农药的回收率为82.1%~94.0%,变异系数≤3.54%,方法的最低检出限为0.009 2~0.038 mg/kg.研究证明,基质固相分散萃取-液相色谱-柱后衍生方法简便、快速、准确、灵敏、节省样品和有机溶剂,可满足小麦中多种氨基甲酸酯农药残留同时检测的需要.%We studied a method for determining 6 kinds of carbamate pesticides in wheat using C18 matrix solid-phase dispersion extraction (MSPDE), high performance liquid chromatography, post-column derivation technique and fluorescence detector. Through the tests of the chromatographic conditions, the selection of matrix solid-phase dispersion material and the ratio of matrix solid-phase dispersion to the sample, the elution conditions and the standard recovery, we established and optimized the MSPDE-HPLC-FLD multi-residue analysis method for determining 6 kinds of carbamate pesticides in wheat. The results showed that the yield of the 6 kinds of carbamate pesticides in wheat reached 82.1% to 94.0 %, the coefficient of variation was equal to or less than 3.54 %, and the lowest detection limit was 0.009 2 to 0.038 0 mg/kg. It is testified that the method is simple, rapid, accurate, sensitive, and saving of samples and organic solvent, and can meet the requirement for simultaneously determining multiple kinds of carbamate pesticides in wheat.

  3. Effets de l'exposition à un insecticide carbamate, le carbofuran, sur les performances de jeunes stades de brochet (Esox lucius L., 1758 : résultats préliminaires

    Directory of Open Access Journals (Sweden)

    AMBLARD G.

    1998-07-01

    Full Text Available Des lots de jeunes brochets au stade embryon libre, stabulés dans des béchers en verre, ont été exposés en conditions statiques à des solutions (0-250 µg.L-1 de carbofuran, un insecticide carbamate inhibiteur de l'activité de l'acétylcholinestérase (AchE. A partir de 10 µg.L-1, une inhibition significative de l'activité globale de l'AchE des embryons libres a été constatée. A partir de 50 µg.L-1, une diminution significative de la hauteur moyenne de fixation des embryons libres sur les parois des béchers a été observée. L'exposition au carbofuran n'a pas eu d'effet significatif sur le nombre de proies zooplanctoniques ingérées par les jeunes brochets parvenus au début de la phase larvaire ; une diminution de ce paramètre en fonction de concentrations croissantes de carbofuran a cependant été enregistrée. A 250 µg.L-1 , la résorption de la vésicule vitelline ne s'effectuant plus que très partiellement, les embryons libres exposés ne se sont pas transformés en larves. Cette étude montre que l'exposition à des concentrations sublétales de carbofuran est susceptible d'affecter le développement ontogénétique et les performances de jeunes stades de brochet. Un approfondissement de ces travaux est envisagé dans différentes directions.

  4. Hydroxycarboxylic acids and salts

    Energy Technology Data Exchange (ETDEWEB)

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  5. Effect of low-temperature storage, gamma irradiation and iso-propyl-N-(3-chlorophenyl carbamate) treatment on the processing quality of potatoes

    International Nuclear Information System (INIS)

    In Taiwan commercial storage of potatoes (CV Kennebec, Wu-Foon, Cardinal) at 2°C. 85% RH, can supply the fresh market all year round. However, reducing sugar and total sugar which accumulate in the tubers will reduce the processing quality of potatoes. Reconditioning of tubers from cold stores was undertaken at ambient temperature (20°C) for up to 6 weeks. The optimum temperature for Kennebec and Cardinal reconditioning ranged from 20 to 25°C. However, after storage at 2°C for a long period, the sugar content of potato tubers cannot be reduced to a satisfactory level. When newly harvested potatoes were pretreated with CIPC (300–500 μg litre−1) and stored at 10°C, 80 % RH, sprouting was inhibited effectively. The quality of potatoes was retained well and reducing sugar remained at a low level for up to 8 months. MENA was found to be ineffective. Gamma irradiation of potatoes at 0.175-0 20·0-10–0.125 and 0.125 kGy for Cardinal, Kennebec and Wu-Foon respectively was found to be effective in controlling the sprouting of tubers stored at 10°C, 80 % RH, for 9 months. A rapid increase in sugar content was found in irradiated Cardinal and Wu-Foon after storage for 7 months, while the reducing sugar in irradiated Kennebec was still below 0°2 % after 8 month's storage. Gamma irradiation had no adverse effect on the ascorbic acid content, and higher firmness retention was obtained in irradiated tubers throughout storage at 10°C

  6. The use of mixed self-assembled monolayers as a strategy to improve the efficiency of carbamate detection in environmental monitoring

    International Nuclear Information System (INIS)

    We report a simple strategy to obtain an efficient enzymatic bioelectrochemical device, in which the enzyme acetylcholinesterase (AChE) was immobilized on gold electrodes functionalized with mixed self-assembled monolayer (SAMmix) of 11-mercaptoundecanoic acid (11-MUA) and 2-mercaptoethanol (C2OH). Development of the modified electrodes included the chemical adsorption of SAMmix on gold surface followed by immersion in AChE solution, resulting in the final Au/SAMmix/AChE configuration. For comparison, the electrochemical performance of Au/11-MUA/AChE and Au/C2OH/AChE electrodes were also investigated. The performance of the modified electrodes toward acetylthiocholine hydrolysis was investigated via cyclic voltammetry and chronoamperometric measurements, revealing a fast increase in anodic current with a well-defined peak upon addition of acetylthiocholine iodide to the electrolytic solution. The anodic currents for Au/SAMmix/AChE electrodes were significantly higher than those for Au/11-MUA/AChE and Au/C2OH/AChE electrodes. The Au/SAMmix/AChE architecture provided by the SAMmix surface promoted a high oxidation current of thiocholine at 0.31 V without the need of electron mediators. The chronoamperometric biosensor developed here provided a linear response to carbaryl in the concentration range of 0 to 1.75 μM. The detection limit and quantification values for carbaryl were found to be 3.45 × 10−10 M and 1.15 × 10−9 M, respectively. Michaelis–Menten kinetics, KMapp, of 0.46 mM was obtained, indicating that the electrode architecture employed is advantageous for fabrication of enzymatic devices via physical adsorption process with improvement of the biocatalytic properties.

  7. UPLC-TOF MS Method for Rapid Screening of Carbamate Insecticides in Agricultural Inputs%超高效液相色谱-飞行时间质谱法快速筛查农业投入品中违规添加的氨基甲酸酯类农药

    Institute of Scientific and Technical Information of China (English)

    陈建波; 马琳; 黄兰淇

    2016-01-01

    建立了12种氨基甲酸酯类农药的超高效液相色谱-飞行时间质谱的快速筛查方法,并将其应用于100个乳油和可湿性粉剂样品的筛查中。结果表明,在农药样品中违规添加的成分包括克百威、丁硫克百威等。在0.5~100 mg/L范围内,12种氨基甲酸酯类农药的线性关系良好,相关系数均大于0.99,方法的加标回收率在85%~103%之间。%A method for rapid screening of 12 kinds of carbamate insecticides in agricultural inputs was established by UPLC-TOF MS, and the method was applied to screen carbamate insecticides in EC and WP. The results showed that carbofuran and carbosulfan were determined in the samples. At the concentration of 0.5-100 mg/L, the linear relationship was good, the correlation coefficients were more than 0.99. The recoveries were 85%-103%.

  8. 固相膜萃取-高效液相色谱法测定饮用水中12种氨基甲酸酯类农药残留%Determination of twelve carbamate residues in drinking water by HPLC after solid-phase membrane extraction

    Institute of Scientific and Technical Information of China (English)

    杨晓松; 余辉菊; 马子元

    2012-01-01

    目的:建立固相膜萃取-高效液相色谱法测定饮用水中灭多威、涕灭威、速灭威、残灭威、呋喃丹、甲萘威、抗杀虫威、异丙威、硫双威、仲丁威、猛杀威、杀虫威等12种氨基甲酸酯类农药残留量的方法.方法:水样经C18固相萃取膜真空抽滤,滤膜用乙酸乙酯洗脱,洗脱液经氮吹、甲醇溶解,高效液相色谱法测定.结果:12种氨基甲酸酯类农药的线性范围为0.05 mg/L~25.0 mg/L,线性相关系数大于0.999,检出限为0.31 mg/L~1.25 mg/L,水样中氨基甲酸酯类农残最低检测浓度范围为0.005 mg/L~0.019 mg/L,加标回收率为59.3%~97.3%,RSD<7.5%.结论:本方法样品前处理方便、快捷,有机试剂用量少.%Objective:To establish a method for determination of 12 carbamate residues including methomyl, al-dicarb, metolcarb, profluoralin, furadan, methyl carbamate, pirimicarb, isoprocarb, thiodicarb, fenobucarb, promecarb and tetrachlorvinphose in drinking - water by high performance liquid chromatography after solid - phase membrane extraction. Methods: The water sample was filtered through the conditioned solid - phase membrane under vacuum. The carbamales absorbed on the membrane were eluted using ethyl acetate and the eluted solution was blown to dryness under nitrogen gas. The residue was reconstituted with methanol and analyzed by HPLC. Results: The linear range of 12 carbamates residues were between 0. 05 mg/L to 25. 0 mg/L with r >0. 999. The detection limits were 0. 31 mg/L to 1.25 mg/L. The lowest detection limits of carbamate residues in the sample water were between 0.005 mg/L and 0.019 mg/L. The recoveries ranged from 59. 3% to 97. 3% with RSD <7.5% . Conclusion: The method can be used for the multi -residue analysis of carbamate residues in drinking water.

  9. 动态微波辅助萃取法快速萃取苹果中8种氨基甲酸酯类农药%Rapid extraction of carbamate pesticides from apple on dynamic microwave-assisted extraction

    Institute of Scientific and Technical Information of China (English)

    刘密兰; 曾庆磊; 丁兰; 金海燕

    2014-01-01

    目的:建立一种绿色的动态微波辅助快速萃取法结合高效液相色谱-串联质谱法测定苹果中8种氨基甲酸酯类农药的方法。方法以水为萃取溶剂,利用动态微波辅助萃取法对苹果中氨基甲酸酯类农药进行快速萃取;通过两步固相萃取法对所获得的萃取物进行净化和富集;采用高效液相色谱-串联质谱法对目标化合物进行测定。结果实验中对影响动态微波辅助萃取和固相萃取效率的实验条件进行了优化,最优的实验条件为:萃取剂为纯水;微波萃取功率为600 W;微波萃取时间为10 min;萃取剂流速为1.0 mL/min;固相萃取洗脱剂为2 mL的乙醇。8种氨基甲酸酯类农药在8.0~800 ng/g范围内成线性关系,相关系数为0.994~0.999;检出限为1.1~4.2 ng/g;方法的加标(8.0 ng/g)回收率为71%~90%。结论该方法可以用于苹果中氨基甲酸酯类农药的快速检测。%Objective A green and fast sample pretreatment method was proposed for determination of 8 carbamate pesticides from apple. Methods The 8 carbamate pesticides in apple samples were extracted by dynamic microwave-assisted extraction with water as extraction solvent. The extract obtained was purified by two steps SPE. Finally, the extract was injected into the LC-MS/MS system for analysis. The parameters which could affect the extraction efficiency were optimized. Results The optimized extraction conditions were observed at water as extraction solvent; 600 W of microwave forward power; extraction time, 10 min;extraction solvent flow-rate, 1.0 mL/min; 2 mL ethanol as the elution solvent of SPE. The linearity ranges of the proposed method from 8.0 to 800 ng/g were obtained and the correlation coefficient were 0.994~0.999. The limits of detection for the eight carbamate pesticides were in the range of 1.1~4.2 ng/g. The recoveries of the eight carbamate pesticides for the spiked samples (8.0 ng/g) were in the range of 71

  10. Understanding Acid Rain

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  11. Dehydroabietic acid

    Directory of Open Access Journals (Sweden)

    Xiao-Ping Rao

    2009-10-01

    Full Text Available The title compound [systematic name: (1R,4aS,10aR-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds.

  12. Dynamic Acid/Base Equilibrium in Single Component Switchable Ionic Liquids and Consequences on Viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Cantu Cantu, David; Lee, Jun Taek; Lee, Mal Soon; Heldebrant, David J.; Koech, Phillip K.; Freeman, Charles J.; Rousseau, Roger J.; Glezakou, Vassiliki Alexandra

    2016-05-05

    The deployment of transformational non-aqueous CO2-capture solvent systems is encumbered by high viscosity even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we identify the key molecular features controlling bulk liquid viscosity and CO2 uptake kinetics. Fast uptake kinetics arise from close proximity of the alcohol and amine sites that are involved in CO2 binding. This process results in the concerted formation of a Zwitterion containing both an alkylcarbonate and a protonated amine. The hydrogen bonding between the two functional groups ultimately determines the solution viscosity. Based on molecular simulation, this work reveals options to significantly reduce viscosity with molecular modifications that shift the proton transfer equilibrium towards a neutral acid/amine species as opposed to the ubiquitously accepted Zwitterionic state. The molecular design concepts proposed here, for the alkyl-carbonate systems, are readily extensible to other CO2 capture technologies, such as the carbamate- or imidazole-based solvent chemistries.

  13. Penetration of methyl isocyanate through organic vapor and acid gas respirator cartridges.

    Science.gov (United States)

    Moyer, E S; Berardinelli, S P

    1987-04-01

    Methyl isocyanate (MIC) is a volatile, toxic chemical [Threshold Limit Value (TLV) = 0.02 ppm] used to manufacture carbamate pesticides. The principal manufacturer of MIC is Union Carbide, and the site of production is Institute, West Virginia. In light of the December 1984 Bhopal, India disaster and possible safety problems at the Institute facility, NIOSH conducted this research as a basis upon which to recommend protective equipment that might be used in an emergency situation where extremely high MIC concentrations might be encountered. Both protective clothing and respirators were evaluated. In particular, NIOSH studied air-purifying respirators in order to assess their effectiveness against MIC vapor penetration. NIOSH does not recommend any air purifying respirator for MIC because of its high toxicity and lack of warning properties and because no effective end of service life indicator currently is available for MIC. This report addresses only MIC penetration through air-purifying cartridges at challenge concentrations designed to simulate emergency escape conditions. Another report addresses the protective clothing issue. The results presented are for two different manufacturers' organic vapor (OV) and acid gas cartridges. Penetration tests were conducted at three or four MIC challenge concentrations and at three different humidity conditions. In general, breakthrough times (1% of challenge concentration) were very short (less than 20 min). Also, high relative humidity was found to decrease the breakthrough time of MIC. PMID:3591646

  14. Precolumn derivatization reagents for high-speed analysis of amines and amino acids in biological fluid using liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Shimbo, Kazutaka; Oonuki, Takashi; Yahashi, Akihisa; Hirayama, Kazuo; Miyano, Hiroshi

    2009-05-01

    A rapid analytical method for amines and amino acids was developed, involving derivatization with the novel reagent 3-aminopyridyl-N-hydroxysuccinimidyl carbamate (APDS), followed by reversed-phase high-performance liquid chromatography and electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). More than 100 different analytes with amino groups, including amino acids in biological fluids such as mammalian plasma, could be measured within 10 min. The analytes were easily derivatized with APDS under the mild conditions. Selective reaction monitoring of ESI-MS/MS in positive mode was carried out to include the transitions of all of the protonated molecular ions of analytes derivatized with APDS to the common fragment at m/z 121, which was derived from the amino pyridyl moiety of the reagent. We evaluated the retention time precision, the quantification limits, the linearity, the intra- and inter-day precisions and the accuracy of 22 typical amino acids found in biological fluids, by analyzing a standard amino acid mixture and rat plasma. The intra-day relative standard deviations (RSDs) of the retention times of the 22 amino acids and their internal standards were within 0.9% and the inter-day RSDs were less than 1.1%, except for asparagines, with an RSD of 1.9%. The intra-day and inter-day RSDs of amino acid analyses in rat plasma were within 8.0% and 4.5%, respectively. The method, which facilitates the amino acid analysis of more than 100 samples in a day, represents an alternative to traditional amino acid analysis techniques, such as chromatography using postcolumn derivatization by ninhydrin. PMID:19350529

  15. Enantioseparation of N-derivatized amino acids by micro-liquid chromatography/laser induced fluorescence detection using quinidine-based monolithic columns.

    Science.gov (United States)

    Wu, Huihui; Wang, Qiqin; Ruan, Meng; Peng, Kun; Zhu, Peijie; Crommen, Jacques; Han, Hai; Jiang, Zhengjin

    2016-03-20

    A novel carbamoylated quinidine based monolith, namely poly(O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine-co-ethylene dimethacrylate (poly(MQD-co-EDMA)), was prepared for the micro-LC enantioseparation of N-derivatized amino acids. The influence of the mobile phase composition, including the organic modifier proportion, the apparent pH and the buffer concentration, on the enantioresolution of N-derivatized amino acids was systematically investigated. Satisfactory column performance in terms of permeability, efficiency and reproducibility was obtained in most cases. The majority of the enantiomers of the tested N-protected amino acids, including 3,5-DNB, 3,5-DClB, FMOC, 3,5-DMB, p-NB, m-ClB, p-ClB and B derivatives, could be baseline separated on the poly(MQD-co-EDMA) monolithic column within 25min. A self-assembled laser induced fluorescence (LIF) detector was employed to improve sensitivity when analyzing 7-nitro-2,1,3-benzoxadiazole (NBD) derivatives of amino acids. Ten NBD-derivatized amino acids, including arginine and histidine whose enantioseparation on quinidine carbamate based CSPs has not been reported so far, were enantioresolved on the poly(MQD-co-EDMA) monolith column. It is worth noting that the d-enantiomers of NBD-derivatized amino acids eluted first, except in the case of glutamic acid. The LOD values obtained with the LIF detector were comparable to those reported using conventional LC-FL methods. The prepared poly(MQD-co-EDMA) monolithic column coupled with the LIF detector opens up interesting perspectives to the determination of trace d-amino acids in biological samples. PMID:26732881

  16. Retarded acid emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Fast, C.R.; Rixe, F.H.; Duffield, E.L. Jr.

    1972-08-01

    Compositions for use in acidizing hydrocarbon-bearing formations are described. Retarded acid emulsions of prolonged stability make it possible for the acid in this form to be displaced substantial distances out into the formation before becoming spent. The action of acid emulsions for use in acidizing hydrocarbon-bearing formations is prolonged by employing as the principal emulsifying agent an amine salt of dodecylbenzene sulfonic acid. Acid emulsions employing the amine salt of dodecylbenzene sulfonic acid exhibit greater stability than those employing the free acid. (8 claims)

  17. Plasma amino acids

    Science.gov (United States)

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  18. Acid Lipase Disease

    Science.gov (United States)

    ... Enhancing Diversity Find People About NINDS NINDS Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, ... Related NINDS Publications and Information What is Acid Lipase Disease ? Acid lipase disease or deficiency occurs when ...

  19. POLYELEOSTEARIC ACID VESICLES

    Institute of Scientific and Technical Information of China (English)

    LI Zichen; XIE Ximng; FAN Qinghua; FANG Yifei

    1992-01-01

    α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solutionofeleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.

  20. Acid distribution in phosphoric acid fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Okae, I.; Seya, A.; Umemoto, M. [Fuji Electric Co., Ltd., Chiba (Japan)

    1996-12-31

    Electrolyte acid distribution among each component of a cell is determined by capillary force when the cell is not in operation, but the distribution under the current load conditions had not been clear so far. Since the loss of electrolyte acid during operation is inevitable, it is necessary to store enough amount of acid in every cell. But it must be under the level of which the acid disturbs the diffusion of reactive gases. Accordingly to know the actual acid distribution during operation in a cell is very important. In this report, we carried out experiments to clarify the distribution using small single cells.

  1. Rapid determination of 8 urinary carbamate pesticides by liquid chromatography-tandem mass spectrometry%尿中8种氨基甲酸酯类农药快速测定的液相色谱-串联质谱法

    Institute of Scientific and Technical Information of China (English)

    刘华良; 王媛; 朱宝立

    2015-01-01

    目的 建立尿中8种氨基甲酸酯类农药同时测定的方法.方法 尿样用乙腈沉淀蛋白后,用液相色谱-串联质谱法进行测定,外标法定量,其中色谱柱采用C18超高效液相色谱柱,流动相为甲醇与乙酸铵溶液梯度淋洗,质谱采集方式为多反应监测.结果 样品中氨基甲酸酯类农药的线性范围为20~800 μg/L,当添加浓度为20、200、800 μg/L时,回收率为61.0%~121%,相对标准偏差为1.7%~5.5%.结论 该检测方法各项指标均符合GBZT 210.5-2008《职业卫生标准制定指南第5部分:生物材料中化学物质测定方法》的要求,适用于中毒患者尿中8种氨基甲酸酯类农药的同时检测.%Objective To establish a method for simultaneously determining the urinary concentrations of 8 carbamate pesticides.Methods After being purified by acetonitrile precipitation,urine samples were transferred to a liquid chromatography-tandem mass spectrometry system,and the concentrations of 8 carbamate pesticides were determined by external standard method.A C18 column was used for ultra-high-performance liquid chromatography;methanol/ammonium acetate solution was used as the mobile phase for gradient elution;the mass spectrometer was operated in a multi-reaction monitoring mode.Results The calibration curves were linear when the urinary concentrations of these carbamate pesticides were 20~800 μg/L,and the recovery rates were 61.0%~121% at spiked levels of 20,200 and 800 μg/L,with a relative standard deviation of 1.7%~5.5%.Conclusion This determination method meets the Guide for establishing occupational health standards-part 5:Determination methods of chemicals in biological materials,and can be used for simultaneous determination of 8 carbamate pesticides in the urine of poisoning patients.

  2. L'acétylcholinestérase des poissons, cible des organophosphorés et des carbamates. Caractérisation du gène et des formes moléculaires de l'enzyme chez Danio rerio. Effets des anticholinestérasiques

    Directory of Open Access Journals (Sweden)

    BERTRAND C.

    1998-07-01

    Full Text Available L'acétylcholinestérase (AChE, EC 3.1.1.7 est une enzyme indispensable de la transmission synaptique cholinergique. Son inhibition par les organophosphorés et les carbamates est à la base de certains traitements insecticides et nématicides utilisés en agriculture. Les faunes sauvage (en particulier les poissons et domestique sont exposées aux résidus des traitements anticholinestérasiques. La mesure de l'inhibition de l'activité AChE chez ces espèces est un marqueur fiable de l'exposition. Ceci est montré ici pour l'AChE de carpes exposées expérimentalement au carbofuran (carbamate. Nous présentons parallèlement des données sur le gène de l'AChE chez Danio rerio et sur les formes moléculaires de l'enzyme chez Danio, Cyprinus carpio et Oncorhynchus mykiss. Contrairement à ce qui est observé chez d'autres vertébrés, le gène d'AChE de Danio ne possède pas d'exon H et seules les sous-unités de type T ont pu être identifiées chez ces trois espèces. Des résultats préliminaires d'hybridation in situ sur les embryons sont présentés et nous discutons l'intérêt des expériences de transgenèse dans l'oeuf de Danio pour étudier d'éventuelles fonctions morphogénétiques de l'AChE au début du développement.

  3. Structure of acetylglutamate kinase, a key enzyme for arginine biosynthesis and a prototype for the amino acid kinase enzyme family, during catalysis.

    Science.gov (United States)

    Ramón-Maiques, Santiago; Marina, Alberto; Gil-Ortiz, Fernando; Fita, Ignacio; Rubio, Vicente

    2002-03-01

    N-Acetyl-L-glutamate kinase (NAGK), a member of the amino acid kinase family, catalyzes the second and frequently controlling step of arginine synthesis. The Escherichia coli NAGK crystal structure to 1.5 A resolution reveals a 258-residue subunit homodimer nucleated by a central 16-stranded molecular open beta sheet sandwiched between alpha helices. In each subunit, AMPPNP, as an alphabetagamma-phosphate-Mg2+ complex, binds along the sheet C edge, and N-acetyl-L-glutamate binds near the dyadic axis with its gamma-COO- aligned at short distance from the gamma-phosphoryl, indicating associative phosphoryl transfer assisted by: (1) Mg2+ complexation; (2) the positive charges on Lys8, Lys217, and on two helix dipoles; and (3) by hydrogen bonding with the y-phosphate. The structural resemblance with carbamate kinase and the alignment of the sequences suggest that NAGK is a structural and functional prototype for the amino acid kinase family, which differs from other acylphosphate-making devices represented by phosphoglycerate kinase, acetate kinase, and biotin carboxylase. PMID:12005432

  4. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Science.gov (United States)

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  5. Acid Deposition Phenomena

    International Nuclear Information System (INIS)

    Acid deposition, commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as wet deposition (rain, snow, cloud, fog) or dry deposition (dry particles, gas). Rain and snow are already naturally acidic, but are only considered problematic when less than a ph of 5.0 The main chemical precursors leading to acidic conditions are atmospheric concentrations of sulfur dioxide (SO2) and nitrogen oxides (NOx). When these two compounds react with water, oxygen, and sunlight in the atmosphere, the result is sulfuric (H2SO4) and nitric acids (HNO3), the primary agents of acid deposition which mainly produced from the combustion of fossil fuel and from petroleum refinery. Airborne chemicals can travel long distances from their sources and can therefore affect ecosystems over broad regional scales and in locations far from the sources of emissions. According to the concern of petroleum ministry with the environment and occupational health, in this paper we will discussed the acid deposition phenomena through the following: Types of acidic deposition and its components in the atmosphere Natural and man-made sources of compounds causing the acidic deposition. Chemical reactions causing the acidic deposition phenomenon in the atmosphere. Factors affecting level of acidic deposition in the atmosphere. Impact of acid deposition. Procedures for acidic deposition control in petroleum industry

  6. Improved detection of β-N-methylamino-L-alanine using N-hydroxysuccinimide ester of N-butylnicotinic acid for the localization of BMAA in blue mussels (Mytilus edulis).

    Science.gov (United States)

    Andrýs, Rudolf; Zurita, Javier; Zguna, Nadezda; Verschueren, Klaas; De Borggraeve, Wim M; Ilag, Leopold L

    2015-05-01

    β-N-Methylamino-L-alanine (BMAA) is an important non-protein amino acid linked to neurodegenerative diseases, specifically amyotrophic lateral sclerosis (ALS). Because it can be transferred and bioaccumulated higher up the food chain, it poses significant public health concerns; thus, improved detection methods are of prime importance for the identification and management of these toxins. Here, we report the successful use of N-hydroxysuccinimide ester of N-butylnicotinic acid (C4-NA-NHS) for the efficient separation of BMAA from its isomers and higher sensitivity in detecting BMAA compared to the current method of choice using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization. Implementation of this efficient method allowed localization of BMAA in the non-visceral tissues of blue mussels, suggesting that more efficient depuration may be required to remove this toxin prior to consumption. This is a crucial method in establishing the absence or presence of the neurotoxic amino acid BMAA in food, environmental or biomedical samples. PMID:25821115

  7. Omega-6 Fatty Acids

    Science.gov (United States)

    ... Some types are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean oils. Other ... ACIDS are as follows:Improving mental development or growth in infants. Adding arachidonic acid (an omega-6 ...

  8. Zoledronic Acid Injection

    Science.gov (United States)

    ... experience a reaction during the first few days after you receive a dose of zoledronic acid injection. Symptoms ... symptoms may begin during the first 3 days after you receive a dose of zoledronic acid injection and ...

  9. Catalytic Synthesis Lactobionic Acid

    Directory of Open Access Journals (Sweden)

    V.G. Borodina

    2014-07-01

    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  10. Plasma amino acids

    Science.gov (United States)

    Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

  11. Omega-3 Fatty Acids

    Science.gov (United States)

    Omega-3 fatty acids are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount ... the blood in people with very high triglycerides. Omega-3 fatty acids are in a class of medications ...

  12. Scientific Opinion on Flavouring Group Evaluation 20, Revision 4 (FGE.20Rev4): Benzyl alcohols, benzaldehydes, a related acetal, benzoic acids, and related esters from chemical groups 23 and 30

    OpenAIRE

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF)

    2012-01-01

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 45 flavouring substances in the Flavouring Group Evaluation 20, Revision 4 (FGE.20Rev4), using the Procedure in Commission Regulation (EC) No 1565/2000. This revision 4 is made due to inclusion of four additional substances, o-, m- and p-tolualdehyde [FL no: 05.026, 05.028 and 05.029] and phenylmethyl 2-methyl-2-butenoate [FL no: 09.858]. None of the su...

  13. The Acid Rain Reader.

    Science.gov (United States)

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  14. Acid Rain Study Guide.

    Science.gov (United States)

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  15. Immunoglobulin and fatty acids

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising 0.1-10 w/w % immunoglobulin (Ig), 4-14 w/w % saturated fatty acids, 4-14 w/w % mono-unsaturated fatty acids and 0-5 w/w % poly-unsaturated fatty acids, wherein the weight percentages are based on the content of dry matter in the composition...

  16. Cleavage of nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor L. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2007-12-11

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  17. Cleavage of nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Waunakee, WI); Lyamichev, Victor I. (Madison, WI); Brow; Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2010-11-09

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  18. Nucleic acid detection compositions

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann (Madison, WI); Dahlberg, James L. (Madison, WI)

    2008-08-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  19. Nucleic acid detection assays

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James E.

    2005-04-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  20. Cleavage of nucleic acids

    Science.gov (United States)

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    2000-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  1. Acidizing carbonate reservoirs with chlorocarboxylic acid salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, E.A.; Scheuerman, R.F.; Templeton, C.C.

    1978-10-31

    A carbonate reservoir is acidized slowly by injecting an aqueous solution of a chlorocarboxylic acid salt so that the rate of the acidization is limited to the rate at which an acid is formed by the hydrolyzing of the chlorocarboxylate ions. The rate at which a chlorocarboxylic acid salt hydrolyzes to form an acid provides the desired rate of acid-release. A more complete acid-base reaction by chloroacetic acid, as compared to formic, acetic, and proprionic, is due to its being a much stronger acid. The pKa of chloroacetic acid is 2.86, whereas that of formic acid is 3.75, and that of acetic acid is 4.75. The pKa of a solution of a weak acid is the pH exhibited when the concentration of undissociated acid equals the concentration of the acid anion. 14 claims.

  2. Nucleic acid detection kits

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann; Kwiatkowski, Robert W.; Vavra, Stephanie H.

    2005-03-29

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of nucleic acid from various viruses in a sample.

  3. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition. PMID:27175515

  4. Research on detection method of pesticides residues of organic phosphorus and carbamate in vegetables and fruits%蔬菜、水果中16种有机磷和氨基甲酸酯农药残留检测方法研究

    Institute of Scientific and Technical Information of China (English)

    郝宁

    2012-01-01

    [ Objective]To establish a method for rapidly detecting 16 kinds of pesticides residues of organic phosphorus and carba-mate in vegetables and fruits [Methods] The detection was conducted by applying gas chromatography with quartz capillary, by u-sing nitrogen-phosphorus detector with high sensitivity and through extracting sample by acetonitrile and acetone. [ Results] the linear ranges of organophosphorus pesticides were 5. 0-1 000. 0 μg/kg, r>0. 999 0. The lowest determination limit was 0. 1- 0. 5 μg/kg, the recoveries were 66.0% -84.0% , and RSD was 4. 8% -9.5% [ Conclusion] This method can determine organic phosphorus and carbamate pesticides simultaneously in vegetables and fruits. It has the characteristics of high sensitivity, good separating effect, high recovery rate, small variance coefficient and low determination limit.%目的 建立一种快速测定蔬菜、水果中有机磷和氨基甲酸酯16种农药残留的方法.方法 应用石英毛细管气相色谱法,利用高灵敏氮磷检测器,用乙腈和丙酮提取样品进行检测.结果 该方法检测16种农药残留的线性范围为5.0~1 000.0 μg/kg,相关系数≥0.9990,最低检出浓度为0.1~0.5 μg/kg,样品加标回收率为66.0%~84.0%,RSD为4.8%~9.5%.结论 该方法能同时测定蔬菜、水果中的有机磷和氨基甲酸酯类农药,具有灵敏度高、分离效果好、回收率高、变异系数小、检出限低的特点.

  5. Microorganisms for producing organic acids

    Energy Technology Data Exchange (ETDEWEB)

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

    Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

  6. The restrained expression of NF-kB in renal tissue ameliorates folic acid induced acute kidney injury in mice.

    Science.gov (United States)

    Kumar, Dev; Singla, Surinder K; Puri, Veena; Puri, Sanjeev

    2015-01-01

    The Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) represent family of structurally-related eukaryotic transcription factors which regulate diverse array of cellular processes including immunological responses, inflammation, apoptosis, growth & development. Increased expression of NF-kB has often been seen in many diverse diseases, suggesting the importance of genomic deregulation to disease pathophysiology. In the present study we focused on acute kidney injury (AKI), which remains one of the major risk factor showing a high rate of mortality and morbidity. The pathology associated with it, however, remains incompletely known though inflammation has been reported to be one of the major risk factor in the disease pathophysiology. The role of NF-kB thus seemed pertinent. In the present study we show that high dose of folic acid (FA) induced acute kidney injury (AKI) characterized by elevation in levels of blood urea nitrogen & serum creatinine together with extensive tubular necrosis, loss of brush border and marked reduction in mitochondria. One of the salient observations of this study was a coupled increase in the expression of renal, relA, NF-kB2, and p53 genes and proteins during folic acid induced AKI (FA AKI). Treatment of mice with NF-kB inhibitor, pyrrolidine dithio-carbamate ammonium (PDTC) lowered the expression of these transcription factors and ameliorated the aberrant renal function by decreasing serum creatinine levels. In conclusion, our results suggested that NF-kB plays a pivotal role in maintaining renal function that also involved regulating p53 levels during FA AKI. PMID:25559736

  7. Bile acid sequestrants

    DEFF Research Database (Denmark)

    Hansen, Morten; Sonne, David P; Knop, Filip K

    2014-01-01

    Bile acids are synthesized in the liver from cholesterol and have traditionally been recognized for their role in absorption of lipids and in cholesterol homeostasis. In recent years, however, bile acids have emerged as metabolic signaling molecules that are involved in the regulation of lipid and...... glucose metabolism, and possibly energy homeostasis, through activation of the bile acid receptors farnesoid X receptor (FXR) and TGR5. Bile acid sequestrants (BASs) constitute a class of drugs that bind bile acids in the intestine to form a nonabsorbable complex resulting in interruption of the...... enterohepatic circulation. This increases bile acid synthesis and consequently reduces serum low-density lipoprotein cholesterol. Also, BASs improve glycemic control in patients with type 2 diabetes. Despite a growing understanding of the impact of BASs on glucose metabolism, the mechanisms behind their glucose...

  8. Docosahexaenoic Acid Neurolipidomics

    OpenAIRE

    Niemoller, Tiffany D.; Bazan, Nicolas G.

    2009-01-01

    Mediator lipidomics is a field of study concerned with the characterization, structural elucidation and bioactivity of lipid derivatives generated by enzymatic activity. Omega-3 fatty acids have beneficial effects for vision, brain function, cardiovascular function, and immune-inflammatory responses. Docosahexaenoic acid [DHA; 22:6(n-3)], the most abundant essential omega-3 fatty acid in the human body, is selectively enriched and avidly retained in the central nervous system as an acyl chain...

  9. Fatty acids and epigenetics

    OpenAIRE

    Burdge, Graham C; Lillycrop, Karen A.

    2014-01-01

    Purpose of review The purpose of this review is to assess the findings of recent studies on the effects of fatty acids on epigenetic process and the role of epigenetics in regulating fatty acid metabolism. Recent findings The DNA methylation status of the Fads2 promoter was increased in the liver of the offspring of mice fed an ?-linolenic acid-enriched diet during pregnancy. In rats, increasing total maternal fat intake during pregnancy and lactation induced persistent hypermethyl...

  10. USGS Tracks Acid Rain

    Science.gov (United States)

    Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

    1995-01-01

    The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

  11. Azetidinic amino acids

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie;

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...

  12. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also....... However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their...

  13. The acid rain primer

    International Nuclear Information System (INIS)

    Acid rain continues to be a major problem in North America, and particularly in eastern Canada. This report introduced the topic of acid rain and discussed its formation, measurement, sources, and geographic distribution. The major sources of sulphur dioxide in Canada are smelting metals, burning coal for electrical power generation, industrial emissions (e.g., pulp and paper, petroleum and aluminum industry), and oil and gas extraction and refining. In Canada, the largest source of nitrogen oxide is the burning of fossil fuels by the transportation sector. Problem areas for acid rain in Canada were identified. The effects of acid rain were examined on lakes and aquatic ecosystems, forests and soils, human-made structures and materials, human health, and on visibility. Acid rain policies and programs were then presented from a historical and current context. Ecosystem recovery from acid rain was discussed with reference to acid rain monitoring, atmospheric response to reductions in acid-causing emissions, and ecosystem recovery of lakes, forests, and aquatic ecosystems. Challenges affecting ecosystem recovery were also presented. These challenges include drought and dry weather, decrease of base cations in precipitation, release of sulphate previously stored in soil, mineralization and immobilization of sulphur/sulphates. Last, the report discussed what still needs to be done to improve the problem of acid rain as well as future concerns. These concerns include loss of base cations from forested watersheds and nitrogen deposition and saturation. 21 refs., 2 tabs., 17 figs

  14. THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE

    Science.gov (United States)

    This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

  15. Genomic Phenotyping by Barcode Sequencing Broadly Distinguishes between Alkylating Agents, Oxidizing Agents, and Non-Genotoxic Agents, and Reveals a Role for Aromatic Amino Acids in Cellular Recovery after Quinone Exposure

    Science.gov (United States)

    Svensson, J. Peter; Quirós Pesudo, Laia; McRee, Siobhan K.; Adeleye, Yeyejide; Carmichael, Paul; Samson, Leona D.

    2013-01-01

    Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS), N-Methyl-N-nitrosourea (MNU), N,N′-bis(2-chloroethyl)-N-nitroso-urea (BCNU), N-ethylnitrosourea (ENU)), two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN), benzene-1,4-diol (hydroquinone, HYQ)), and two non-genotoxic (methyl carbamate (MC) and dimethyl sulfoxide (DMSO)) compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic ‘barcode’, were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput ‘barcode’ sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised. PMID:24040048

  16. 4-{3-[Hydroxy(phenylmethyl]-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-4-yl}benzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Mehmet Akkurt

    2010-04-01

    Full Text Available In the title compound, C15H14N4O3S2, the hydroxy group is disordered over two positions with occupancies of 0.619 (5 and 0.381 (5. The benzene ring attached to the heterocycle makes a dihedral angle of 86.92 (9° with respect to the best plane through the five-membered ring. The crystal packing is stabilized by intermolecular O—H...O, N—H...S, N—H...N, C—H...O and C—H...N hydrogen bonds, and N—H...π and C—H...π interactions.

  17. N-[(R-(6-Bromo-2-methoxyquinolin-3-yl(phenylmethyl]-N-[(S-1-(4-methoxyphenylethyl]-2-(piperazin-1-ylacetamide

    Directory of Open Access Journals (Sweden)

    Lei Yuan

    2011-11-01

    Full Text Available In the title compound, C32H35BrN4O3, the piperazine ring exists in a chair conformation. The quinoline ring system is oriented at dihedral angles of 82.70 (17 and 19.54 (17° to the phenyl and methoxyphenyl rings, respectively. Weak intermolecular C—H...π interactions are present in the crystal structure.

  18. Molecular Interaction of Pinic Acid with Sulfuric Acid

    DEFF Research Database (Denmark)

    Elm, Jonas; Kurten, Theo; Bilde, Merete;

    2014-01-01

    We investigate the molecular interactions between the semivolatile α-pinene oxidation product pinic acid and sulfuric acid using computational methods. The stepwise Gibbs free energies of formation have been calculated utilizing the M06-2X functional, and the stability of the clusters is evaluated...... from the corresponding ΔG values. The first two additions of sulfuric acid to pinic acid are found to be favorable with ΔG values of -9.06 and -10.41 kcal/mol. Addition of a third sulfuric acid molecule is less favorable and leads to a structural rearrangement forming a bridged sulfuric acid-pinic acid...... without the further possibility for attachment of either sulfuric acid or pinic acid. This suggests that pinic acid cannot be a key species in the first steps in nucleation, but the favorable interactions between sulfuric acid and pinic acid imply that pinic acid can contribute to the subsequent growth of...

  19. Amino Acid Crossword Puzzle

    Science.gov (United States)

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  20. Science of acid rain

    International Nuclear Information System (INIS)

    In this report, the mechanism of forming acid rain in the atmosphere and the process of its fall to ground, the mechanism of withering forests by acid substances, and the process of acidifying lakes and marshes are explained. Moreover, the monitoring networks for acid rain and the countermeasures are described. Acid rain is the pollution phenomena related to all environment, that is, atmosphere, hydrosphere, soilsphere, biosphere and so on, and it is a local environmental pollution problem, and at the same time, an international, global environmental pollution problem. In Japan, acid rain has fallen, but the acidification of lakes and marshes is not clear, and the damage to forests is on small scale. However in East Asia region, the release of sulfur oxides and nitrogen oxides is much, and the increase of the effects of acid rain is expected. It is necessary to devise the measures for preventing the damage due to acid rain. The global monitoring networks of World Meteorological Organization and United Nations Environment Program, and those in Europe, USA and Japan are described. The monitoring of acid rain in Japan is behind that in Europe and USA. (K.I.)

  1. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  2. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a...

  3. Locked nucleic acid

    DEFF Research Database (Denmark)

    Jepsen, Jan Stenvang; Sørensen, Mads D; Wengel, Jesper;

    2004-01-01

    Locked nucleic acid (LNA) is a class of nucleic acid analogs possessing very high affinity and excellent specificity toward complementary DNA and RNA, and LNA oligonucleotides have been applied as antisense molecules both in vitro and in vivo. In this review, we briefly describe the basic...

  4. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  5. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  6. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  7. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...

  8. Characterization of acid tars

    International Nuclear Information System (INIS)

    Acid tars from the processing of petroleum and petrochemicals using sulfuric acid were characterized by gas chromatography/mass spectrometry (GC/MS), inductively coupled plasma/optical emission spectrometry (ICP/OES), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrometry, and scanning electron microscopy/energy dispersive X-ray (SEM/EDX) micro-analysis. Leaching of contaminants from the acid tars in 48 h batch tests with distilled water at a liquid-to-solid ratio 10:1 was also studied. GC/MS results show that the samples contained aliphatic hydrocarbons, cyclic hydrocarbons, up to 12 of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs), and numerous other organic groups, including organic acids (sulfonic acids, carboxylic acids and aromatic acids), phenyl, nitrile, amide, furans, thiophenes, pyrroles, and phthalates, many of which are toxic. Metals analysis shows that Pb was present in significant concentration. DSC results show different transition peaks in the studied samples, demonstrating their complexity and variability. FTIR analysis further confirmed the presence of the organic groups detected by GC/MS. The SEM/EDX micro-analysis results provided insight on the surface characteristics of the samples and show that contaminants distribution was heterogeneous. The results provide useful data on the composition, complexity, and variability of acid tars; information which hitherto have been scarce in public domain.

  9. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    . However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their...

  10. Canadian acid rain policy

    International Nuclear Information System (INIS)

    On March 13 of 1991, the Prime Minister of Canada, Brian Mulroney and the President of the United States of America, George Bush, signed an Agreement on Air Quality. This agreement enshrines Principle 21 of the 1972 Stockholm Declaration which states that countries are to ensure that activities within their jurisdiction do not cause damage to the environment of another country. This agreement also includes provisions for controlling acid rain. The Agreement on Air Quality followed years of discussion between the two countries and is a significant milestone in the history of Canadian acid rain policy. This paper begins by describing Canadian acid rain policy and its evolution. The paper also outlines the Canada-United States Air Quality Agreement and the effect of the acid rain provisions on deposition in Canada. Finally, it considers the future work that must be undertaken to further resolve the acid rain problem. 8 refs., 5 figs., 1 tab

  11. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures...... of 2,5-anhydrides and not the expected 2-acetamido-2-deoxy aldose phenylhydrazones. The acetylated phenylhydrazones were found to eliminate acetic acid when heated in aqueous ethanol and 1-phenylazoalkenes could be isolated by crystallisation. By this method the 17, 20, 23 and 25 were prepared from...... aziridino amides 43 and 51 were reductively cleaved with hydrazine to give 3-amino-2,3-dideoxyhexonhydrazides 83 and 85, which were easily converted into the corresponding lactone 84 and acid 86. The aziridine ring of 43 and 51 was also opened with acetic acid to give the 3-amino-3-deoxyhexonic acids 79 and...

  12. Fusidic acid in dermatology

    DEFF Research Database (Denmark)

    Schöfer, Helmut; Simonsen, Lene

    1995-01-01

    Studies on the clinical efficacy of fusidic acid in skin and soft-tissue infections (SSTIs), notably those due to Staphylococcus aureus, are reviewed. Oral fusidic acid (tablets dosed at 250 mg twice daily, or a suspension for paediatric use at 20 mg/kg/day given as two daily doses) has shown good...... efficacy and tolerability. Similarly, plain fusidic acid cream or ointment used two or three times daily in SSTIs such as impetigo are clinically and bacteriologically effective, with minimal adverse events. Combination formulations of fusidic acid with 1% hydrocortisone or 0.1% betamethasone achieve...... excellent results in infected eczema by addressing both inflammation and infection. A new lipid-rich combination formulation provides an extra moisturizing effect. Development of resistance to fusidic acid has remained generally low or short-lived and can be minimized by restricting therapy to no more than...

  13. Sulfuric Acid on Europa

    Science.gov (United States)

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer.Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  14. Difficult Decisions: Acid Rain.

    Science.gov (United States)

    Miller, John A.; Slesnick, Irwin L.

    1989-01-01

    Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

  15. Folic acid in diet

    Science.gov (United States)

    ... green leafy vegetables Dried beans and peas (legumes) Citrus fruits and juices Fortified means that vitamins have ... A.D.A.M. Editorial team. Related MedlinePlus Health Topics Folic Acid Browse the Encyclopedia A.D. ...

  16. Citric acid urine test

    Science.gov (United States)

    ... usually done while you are on a normal diet. Ask your provider for more information. ... acidosis and a tendency to form calcium kidney stones. The ... acid levels: A high carbohydrate diet Estrogen therapy Vitamin D

  17. Stomach acid test

    Science.gov (United States)

    Gastric acid secretion test ... The test is done after you have not eaten for a while so fluid is all that remains in ... injected into your body. This is done to test the ability of the cells in the stomach ...

  18. Azelaic Acid Topical

    Science.gov (United States)

    ... pores and by decreasing production of keratin, a natural substance that can lead to the development of ... acid controls acne and rosacea but does not cure these conditions. It may take 4 weeks or ...

  19. Acid rain: An overview

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary of the effects of acid rain and related processes, sources, issues, corrective actions, research, current law, potential solutions, political solutions,...

  20. Ethylenediaminetetraacetic acid in endodontics

    OpenAIRE

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-01-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for...

  1. Utilization of acid tars

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, A.F.; Denisova, T.L.; Aminov, A.N.

    1987-01-01

    Freshly produced acid tar (FPAT), obtained as refinery waste in treating petroleum oils with sulfuric acid and oleum, contains 80% or more sulfuric acid. Of such tars, pond acid tars, which contain up to 80% neutral petroleum products and sulfonated resins, are more stable, and have found applications in the production of binders for paving materials. In this article the authors are presenting results obtained in a study of the composition and reactivity of FPAT and its stability in storage in blends with asphalts obtained in deasphalting operations, and the possibility of using the FPAT in road construction has been examined. In this work, wastes were used which were obtained in treating the oils T-750, KhF-12, I-8A, and MS-14. Data on the change in group chemical composition of FPAT are shown, and the acidity, viscosity, needle penetration, and softening point of acid tars obtained from different grades of oils are plotted as functions of the storage time. It is also shown that the fresh and hardened FPATs differ in their solubilities in various solvents.

  2. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles of...

  3. Neutron Nucleic Acid Crystallography.

    Science.gov (United States)

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination. PMID:26227050

  4. Method for isolating nucleic acids

    Science.gov (United States)

    Hurt, Jr., Richard Ashley; Elias, Dwayne A.

    2015-09-29

    The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

  5. Acidification and Acid Rain

    Science.gov (United States)

    Norton, S. A.; Veselã½, J.

    2003-12-01

    Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that

  6. Preparation and Evaluation of Carbamate Functionalized Ionic Liquid Stationary for High-performance Liquid Chromatography%氨基甲酸酯功能化离子液体高效液相色谱固定相的制备与初步评价

    Institute of Scientific and Technical Information of China (English)

    刘晓鸽; 王宏雁; 杨光云; 毛璞; 何丽君; 肖咏梅; 屈凌波

    2013-01-01

    合成一种了氨基酸衍生物:4,4'-二苯亚甲基桥联-二[2-(1-咪唑基)-3-苯基丙醇氨基甲酸酯](ImPh-Carb),并将其键合到硅胶上制备了一种新的氨基甲酸酯功能化的离子液体HPLC固定相(ImPh-Carb-Silica).利用1 H NMR、13C NMR、MS和FTIR对ImPh-Carb进行了表征;通过FTIR和元素分析对ImPh-Carb-Silica固定相进行了表征,根据N含量计算得到ImPh-Carb-Silica的键合量为0.19 mmol/g.以5种芳烃、5种酚类化合物和4种有机磷农药为分析物,分别在正相和反相色谱模式下对固定相的色谱分离性能进行了评价,同时考察了流动相的变化与溶质保留因子lgk之间的关系.结果表明,该固定相与溶质分子间存在多重作用力,如疏水、氢键、π-π和偶极-诱导偶极作用等,使其能同时在正相和反相色谱模式下使用;在正相色谱条件下固定相对酚类化合物和有机磷农药表现出较好的分离选择性.%A new carbamate functionalized ionic liquid stationary phase (ImPh-Carb-Silica) for highperformance liquid chromatography was prepared by bonding 4,4'-diphenylmethylene-bis [2-(1-imidazolyl)-3-phenyl-l-propanol carbamate] (ImPh-Carb) onto silica particles.The structure of ImPh-Carb was characterized by 1H NMR,13C NMR,MS and FTIR,and the bonded stationary phase was also characterized by FTIR and element analysis,and the bonding amount of ImPh-Carb-Silica stationary phase was about 0.19 mmol/g,according to the nitrogen content.The chromatographic performances of the stationary phase were evaluated using aromatic hydrocarbons,phenols and organophosphorus pesticides as solutes in reversedphase and normal-phase chromatographic modes,and the effect of the content of mobile phase on retention factor(lg k) of analytes was studied.The results show that the functionalized ionic liquid stationary phase provides a multiple-interaction mechanism with analytes including hydrophobic,hydrogen bonding,π-π,and dipole

  7. Determination of β-N-methylamino-L-alanine, N-(2-aminoethyl)glycine, and 2,4-diaminobutyric acid in Food Products Containing Cyanobacteria by Ultra-Performance Liquid Chromatography and Tandem Mass Spectrometry: Single-Laboratory Validation.

    Science.gov (United States)

    Glover, W Broc; Baker, Teesha C; Murch, Susan J; Brown, Paula N

    2015-01-01

    A single-laboratory validation study was completed for the determination of β-N-methylamino-L-alanine (BMAA), N-(2-aminoethyl)glycine (AEG), and 2,4-diaminobutyric acid (DAB) in bulk natural health product supplements purchased from a health food store in Canada. BMAA and its isomers were extracted with acid hydrolysis to free analytes from protein association. Acid was removed with the residue evaporated to dryness and reconstituted with derivatization using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AccQ-Fluor). Chromatographic separation and detection were achieved using RP ultra-performance LC coupled to a tandem mass spectrometer operated in multiple reaction monitoring mode. Data from biological samples were evaluated for precision and accuracy across different days to ensure repeatability. Accuracy was assessed by spike recovery of biological samples using varying amino acid concentrations, with an average recovery across all samples of 108.6%. The analytical range was found to be 764-0.746 ng/mL prior to derivatization, thereby providing a linear range compatible with potentially widely varying analyte concentrations in commercial health food products. Both the U. S. Food and Drug Administration (FDA) and U. S. Pharmacopeia definitions were evaluated for determining method limits, with the FDA approach found to be most suitable having an LOD of 0.187 ng/mL and LLOQ of 0.746 ng/mL. BMAA in the collected specimens was detected at concentrations lower than 1 μg/g, while AEG and DAB were found at concentrations as high as 100 μg/g. Finding these analytes, even at low concentrations, has potential public health significance and suggests a need to screen such products prior to distribution. The method described provides a rapid, accurate, and precise method to facilitate that screening process. PMID:26651568

  8. Acid Rain, pH & Acidity: A Common Misinterpretation.

    Science.gov (United States)

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  9. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

  10. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  11. EFFECT OF ACIDITY ON ACID-SENSITIVE UV CURING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Qi-dao Chen; Bing Wu; Xiao-yin Hong

    1999-01-01

    By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.

  12. Determination of Sialic Acids by Acidic Ninhydrin Reaction

    Directory of Open Access Journals (Sweden)

    Yao,Kenzabroh

    1987-12-01

    Full Text Available A new acidic ninhydrin method for determining free sialic acids is described. The method is based on the reaction of sialic acids with Gaitonde's acid ninhydrin reagent 2 which yields a stable color with an absorption maximum at 470 nm. The standard curve is linear in the range of 5 to 500 nmol of N-acetylneuraminic acid per 0.9 ml of reaction mixture. The reaction was specific only for sialic acids among the various sugars and sugar derivatives examined. Some interference of this method by cysteine, cystine and tryptophan was noted, although their absorption maxima differed from that of sialic acids. The interference by these amino acids was eliminated with the use of a small column of cation-exchange resin. The acidic ninhydrin method provides a simple and rapid method for the determination of free sialic acids in biological materials.

  13. Chemistry and electrochemistry in trifluoroacetic acid. Comparison with acetic acid

    International Nuclear Information System (INIS)

    As the trifluoroacetic acid is, with the acetic acid, one of most often used carboxylic acids as solvent, notably in organic chemistry, this research thesis addresses some relatively simple complexing and redox reactions to highlight the peculiar feature of this acid, and to explain its very much different behaviour with respect to acetic acid. The author develops the notion of acidity level in solvents of low dielectric constant. The second part addresses a specific solvent: BF3(CH3COOH)2. The boron trifluoride strengthens the acidity of acetic acid and modifies its chemical and physical-chemical properties. In the third part, the author compares solvent properties of CF3COOH and CH3COOH. Noticed differences explain why the trifluoroacetic acid is a more interesting reaction environment than acetic acid for reactions such as electrophilic substitutions or protein solubilisation

  14. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    OpenAIRE

    Je Min Lee; Hyungjae Lee; SeokBeom Kang; Woo Jung Park

    2016-01-01

    Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human phys...

  15. Domoic Acid Epileptic Disease

    Directory of Open Access Journals (Sweden)

    John S. Ramsdell

    2014-03-01

    Full Text Available Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis.

  16. A Demonstration of Acid Rain

    Science.gov (United States)

    Fong, Man Wai

    2004-01-01

    A demonstration showing acid rain formation is described. Oxides of sulfur and nitrogen that result from the burning of fossil fuels are the major pollutants of acid rain. In this demonstration, SO[subscript 2] gas is produced by the burning of matches. An acid-base indicator will show that the dissolved gas turns an aqueous solution acidic.

  17. Biological properties of lipoic acid

    OpenAIRE

    Anna Bilska; Lidia Włodek

    2002-01-01

    Lipoic acid is a prostetic group of H-protein of the glycine cleavage system and the dihydrolipoamide acyltransferases (E2) of the pyruvate, alpha-ketoglutarate and branched-chain alpha-keto acid dehydrogenase complexes. Lipoic acid and its reduced form, dihydrolipoic acid, reacts with oxygen reactive species. This paper reviews the beneficial effects in oxidative stress models or clinical conditions.

  18. Amino acid analysis.

    Science.gov (United States)

    Crabb, J W; West, K A; Dodson, W S; Hulmes, J D

    2001-05-01

    Amino acid analysis (AAA) is one of the best methods to quantify peptides and proteins. Two general approaches to quantitative AAA exist, namely, classical postcolumn derivatization following ion-exchange chromatography and precolumn derivatization followed by reversed-phase HPLC (RP-HPLC). Excellent instrumentation and several specific methodologies are available for both approaches, and both have advantages and disadvantages. This unit focuses on picomole-level AAA of peptides and proteins using the most popular precolumn-derivatization method, namely, phenylthiocarbamyl amino acid analysis (PTC-AAA). It is directed primarily toward those interested in establishing the technology with a modest budget. PTC derivatization and analysis conditions are described, and support and alternate protocols describe additional techniques necessary or useful for most any AAA method--e.g., sample preparation, hydrolysis, instrument calibration, data interpretation, and analysis of difficult or unusual residues such as cysteine, tryptophan, phosphoamino acids, and hydroxyproline. PMID:18429107

  19. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    Halogenated fatty acids are the major contributors to organohalogen compounds in lipids of marine mammals, fish, and bivalves. For the initial characterization of these recently noticed compounds, a determination of the halogen concentration has usually been combined with some lipid isolation and...... separation method. This review covers separation by solid phase chromatography, gel permeation chromatography, and liquid-liquid extraction, followed by halogen determination. All studies performed according to this outline have indicated that the major organohalogen compounds are chlorinated fatty acids...... bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD...

  20. [Nicotinic acid and nicotinamide].

    Science.gov (United States)

    Kobayashi, M; Shimizu, S

    1999-10-01

    Nicotinic acid and nicotinamide are called niacin. They are the antipellagra vitamin essential to many animals for growth and health. In human being, niacin is believed necessary together with other vitamins for the prevention and cure of pellagra. Niacin is widely distributed in nature; appreciable amounts are found in liver, fish, yeast and cereal grains. Nicotinamide is a precursor of the coenzyme NAD and NADP. Some of the most understood metabolic processes that involve niacin are glycolysis, fatty acid synthesis and respiration. Niacin is also related to the following diseases: Hartnup disease; blue diaper syndrome; tryptophanuria; hydroxykynureninuria; xanthurenic aciduria; Huntington's disease. PMID:10540864

  1. Whither Acid Rain?

    OpenAIRE

    Peter Brimblecombe

    2000-01-01

    Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and s...

  2. A very acid rocket

    Energy Technology Data Exchange (ETDEWEB)

    Benoit Browaeys, D.

    1996-04-01

    The french rocket Ariane is the cause of environmental pollution. These effects are discussed in this article. Chloric acid and aluminium are in question: chloric acid is responsible of leaves necrosis and pulmonary diseases among the rats. For the man, the danger would be that drinking water could be contaminated by aluminium, which is neuro toxic with serious chronic effects. It is implicated in Alzheimer disease. But no studies has been made to search aluminium in drinking water of Sinnamary and Kourou. (N.C.). 8 refs., 2 figs.

  3. Ethylenediaminetetraacetic acid in endodontics.

    Science.gov (United States)

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-09-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented. PMID:24966721

  4. Whither Acid Rain?

    Directory of Open Access Journals (Sweden)

    Peter Brimblecombe

    2000-01-01

    Full Text Available Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  5. Boric acid concentration monitoring

    International Nuclear Information System (INIS)

    Boric acid concentration was measured by thermal neutron absorption in the study of the boric acid sorption and desorption curves on an anion exchange resin. Ra-Be 18.5 GBq and Am-Be 111 GBq sources and water as a moderator were used. The SNM 12 cylindrical corona detector with 10B placed in the middle of the measuring cell was used for neutron flux measurement. The HP 9600 E computer system was used for measured data collection and evaluation. (Ha)

  6. Polyunsaturated fatty acids and inflammation

    OpenAIRE

    Calder Philip C

    2004-01-01

    The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites) and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and ...

  7. Acid Rain Investigations.

    Science.gov (United States)

    Hugo, John C.

    1992-01-01

    Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

  8. Acid Rain Classroom Projects.

    Science.gov (United States)

    Demchik, Michael J.

    2000-01-01

    Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

  9. The Acid Rain Game.

    Science.gov (United States)

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  10. The Acid Rain Debate.

    Science.gov (United States)

    Oates-Bockenstedt, Catherine

    1997-01-01

    Details an activity designed to motivate students by incorporating science-related issues into a classroom debate. Includes "The Acid Rain Bill" and "Position Guides" for student roles as committee members, consumers, governors, industry owners, tourism professionals, senators, and debate directors. (DKM)

  11. Hyaluronic Acid Assays

    DEFF Research Database (Denmark)

    Itenov, Theis S; Kirkby, Nikolai S; Bestle, Morten H;

    2015-01-01

    BACKGROUD: Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method. METHODS: HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme...

  12. Koetjapic acid chloroform hemisolvate

    Directory of Open Access Journals (Sweden)

    Z. D. Nassar

    2010-06-01

    Full Text Available The asymmetric unit of the title compound, C30H46O4·0.5CHCl3, consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS-7-(2-carboxyethyl-3,4b,7,10b,12a-pentamethyl-8-(prop-1-en-2-yl-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexadecahydrochrysene-3-carboxylic acid] molecule and one half-molecule of chloroform solvent, which is disordered about a twofold rotation axis. The symmetry-independent component is further disordered over two sites, with occupancies of 0.30 and 0.20. The koetjapic acid contains a fused four-ring system, A/B/C/D. The A/B, B/C and C/D junctions adopt E/trans/cis configurations, respectively. The conformation of ring A is intermediate between envelope and half-chair and ring B adopts an envelope conformation whereas rings C and D adopt chair conformations. A weak intramolecular C—H...O hydrogen bond is observed. The koetjapic acid molecules are linked into dimers by two pairs of intermolecular O—H...O hydrogen bonds. The dimers are stacked along the c axis.

  13. Lactic acid and lactates

    NARCIS (Netherlands)

    Schreurs, V.V.A.M.

    2010-01-01

    This review aims to integrate the present state of knowledge on lactate metabolism in human and mammalian physiology as far as it could be subject to nutritional interventions. An integrated view on the nutritional, metabolic and physiological aspects of lactic acid and lactates might open a perspec

  14. Acid dip for dosemeter

    International Nuclear Information System (INIS)

    Background signal in a PTFE based dosemeter caused by impurities in the PTFE and in the active component such as lithium fluoride is substantially reduced by treating the dosemeter with acid. The optimum treatment involves use of hydrofluoric acid at room temperature for approximately one minute, followed by thorough washing with methanol, and finally drying. This treatment is best applied after the original manufacture of the dosemeters. It may also be applied to existing dosemeters after they have been in use for some time. The treatment produces a permanent effect in reducing both the light induced signal and the non-light induced signal. The process may be applied to all types of dosemeter manufactured from PTFE or other plastics or resins which are able to resist brief exposure to acid. The treatment works particularly well with dosemeters based on PTFE and lithium fluoride. It is also applicable to dosemeters based on calcium sulphate, lithium borate and magnesium borate. Acids which may be used include hydrofluoric, hydrochloric, nitric, phosphoric and sulphuric. (author)

  15. Accidents with sulfuric acid

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2006-01-01

    Full Text Available Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eighteen years (from 1988 till the beginning of 2006 are analyzed in this paper. It is very alarming data that, according to all the recorded accidents, over 1.6 million tons of sulfuric acid were exuded. Although water transport is the safest (only 16.38% of the total amount of accidents in that way 98.88% of the total amount of sulfuric acid was exuded into the environment. Human factor was the common factor in all the accidents, whether there was enough control of the production process, of reservoirs or transportation tanks or the transport was done by inadequate (old tanks, or the accidents arose from human factor (inadequate speed, lock of caution etc. The fact is that huge energy, sacrifice and courage were involved in the recovery from accidents where rescue teams and fire brigades showed great courage to prevent real environmental catastrophes and very often they lost their lives during the events. So, the phrase that sulfuric acid is a real "environmental bomb" has become clearer.

  16. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  17. Origin of fatty acids

    International Nuclear Information System (INIS)

    The appearance of fatty acids and membranes is one of the most important events of the prebiotic world because genesis of life required the compartmentalization of molecules. Membranes allowed cells to become enriched with molecules relevant for their evolution and gave rise to gradients convertible into energy. By virtue of their hydrophobic/hydrophilic interface, membranes developed certain enzymatic activities impossible in the aqueous phase. A prebiotic cell is an energy unit but it is also an information unit. It has a past, a present and a future. The biochemistry of fatty acids involves acetylCoA, malonylCoA and an enzyme, acyl synthetase, which joins both molecules. After substitution of the acetyl group in place of the carboxyl group of malonyl derivatives, the chain is reduced and dehydrated to crotonyl derivatives. These molecules can again react with malonylCoA to form unsaturated chain; they can also undergo a new reduction step to form butyryl derivatives which can react with malonylCoA to form a longer aliphatic chain. The formation of malonylCoA consumes ATP. The reduction step needs NADPH and proton. Dehydration requires structural information because the reduction product is chiral (D configuration). It is unlikely that these steps were possible in a prebiotic environment. Thus we have to understand how fatty acids could appear in the prebiotic era. This hypothesis about the origin of fatty acids is based on the chemistry of sulfonium ylides and sulfonium salts. The most well-known among these molecules are S-melthyl-methionine and S-adenosyl methionine. The simplest sulfonium cation is the trimethylsulfonium cation. Chemists have evidence that these products can produce olefin when they are heated or flashed with UV light in some conditions. I suggest that these volatile products can allow the formation of fatty acids chains in atmospheric phase with UV and temperature using methanol as starting material. Different synthetic pathways will be

  18. Photostabilization of ascorbic acid with citric acid, tartaric acid and boric acid in cream formulations.

    Science.gov (United States)

    Ahmad, I; Ali Sheraz, M; Ahmed, S; Shad, Z; Vaid, F H M

    2012-06-01

    This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH(2) ) in oil-in-water cream formulations exposed to the UV light and stored in the dark. The apparent first-order rate constants (0.34-0.95 × 10(-3) min(-1) in light, 0.38-1.24 × 10(-2) day(-1) in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second-order rate constants (0.26-1.45 × 10(-2) M(-1) min(-1) in light, 3.75-8.50 × 10(-3) M(-1) day(-1) in dark) for the interaction of AH(2) and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH(2) both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH(2) in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH(2) -excited triplet state by CT and TA and by the inhibition of AH(2) degradation through complex formation with BA. AH(2) leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations. PMID:22296174

  19. Arterial Blood Carbonic Acid Inversely Determines Lactic and Organic Acids

    OpenAIRE

    Aiken, Christopher Geoffrey Alexander

    2013-01-01

    Objective: To establish that arterial blood carbonic acid varies inversely with lactic acid in accordance with bicarbonate exchanging for lactate across cell membranes through the anion exchange mechanism to maintain the Gibbs-Donnan equilibrium.

  20. Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells

    Directory of Open Access Journals (Sweden)

    Duan Rui-Dong

    2009-12-01

    Full Text Available Abstract Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-β-boswellic acids (AKBA, a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health.

  1. [Lipid synthesis by an acidic acid tolerant Rhodotorula glutinis].

    Science.gov (United States)

    Lin, Zhangnan; Liu, Hongjuan; Zhang, Jian'an; Wang, Gehua

    2016-03-01

    Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis. PMID:27349116

  2. Acetic acid extraction from aqueous solutions using fatty acids

    NARCIS (Netherlands)

    IJmker, H.M.; Gramblicka, M.; Kersten, S.R.A.; Ham, van der A.G.J.; Schuur, B.

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  3. College Chemistry Students' Mental Models of Acids and Acid Strength

    Science.gov (United States)

    McClary, LaKeisha; Talanquer, Vicente

    2011-01-01

    The central goal of this study was to characterize the mental models of acids and acid strength expressed by advanced college chemistry students when engaged in prediction, explanation, and justification tasks that asked them to rank chemical compounds based on their relative acid strength. For that purpose we completed a qualitative research…

  4. N-(3-Methylphenylsuccinamic acid

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-02-01

    Full Text Available In the crystal structure of the title compound, C11H13NO3, the conformations of the N—H and C=O bonds in the amide segment are anti to each other, and that of the amide H atom is anti to the meta-methyl group in the benzene ring. Furthermore, the conformations of the amide oxygen and the carbonyl O atom of the acid segment are also anti to the adjacent –CH2 groups. The C=O and O—H bonds of the acid group are syn to each other. In the crystal, the molecules are packed into infinite chains through intermolecular N—H...O and O—H...O hydrogen bonds.

  5. [Progress in glucaric acid].

    Science.gov (United States)

    Qiu, Yuying; Fang, Fang; Du, Guocheng; Chen, Jian

    2015-04-01

    Glucaric acid (GA) is derived from glucose and commonly used in chemical industry. It is also considered as one of the "Top value-added chemicals from biomass" as carbohydrate monomers to produce various synthetic polymers and bioenergy. The demand for GA in food manufacture is increasing. GA has also attracted public attentions due to its therapeutic uses such as regulating hormones, increasing the immune function and reducing the risks of cancers. Currently GA is produced by chemical oxidation. Research on production of GA via microbial synthesis is still at preliminary stage. We reviewed the advances of glucaric acid applications, preparation and quantification methods. The prospects on production of GA by microbial fermentation were also discussed. PMID:26380405

  6. Studies on terreic acid.

    Science.gov (United States)

    Yamamoto, H; Moriyama, K; Jinnouchi, H; Yagishita, K

    1980-03-01

    It was found that Aspergillus sp. No. Y-8980 which was isolated from a soil sample collected at Yoron Island in Kagoshima Prefecture belonged to Aspergillus terreus group by morphological observation. The active substance produced by the strain was obtained with a high yield in sucrose-yeast extract medium and extracted by chloroform, ethyl acetate and n-butanol at pH 2.4 approximately 2.6 from the culture broth. The substance was crystallized from chloroform and ethyl acetate after charcoal treatment of the crude crystal. From various physico-chemical properties, it was found that the substance was identical to terreic acid. Terreic acid showed MICs of 25 approximately 100 mcg/ml, 12.5 mcg/ml and 50 mcg/ml against Gram-positive and Gram-negative bacteria, Xanthomonas oryzae and Xanthomonas citri, respectively, but it did not control Pseudomonas, fungi and yeast. The LD50 was 75 mg/kg i.p. and i.v. in mice. With regards to the anti-tumor effect, the morphological degeneration on HeLa cells (human carcinoma cells) was observed in the concentrations of more than 6.25 mcg/ml of terreic acid. An increase of body weight of mice caused by Ehrlich ascites carcinoma cells was not definitely observed by the daily administration of 150 mcg of terreic acid per mouse for 8 consecutive days. Above showed the enough survival effect in dd mice implanted with Ehrlich ascites carcinoma cells, and the effect also was demonstrated by anatomies of mice. PMID:7190624

  7. Electrochemistry of nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Bartošík, Martin

    2012-01-01

    Roč. 112, č. 6 (2012), s. 3427-3481. ISSN 0009-2665 R&D Projects: GA ČR(CZ) GAP301/11/2055; GA MŠk(CZ) ME09038; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : nucleic acids electrochemistry * DNA biosensors * DNA damage Subject RIV: BO - Biophysics Impact factor: 41.298, year: 2012

  8. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2007-01-01

    Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness.......Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness....

  9. Pantothenic acid (Vitamin B5)

    Science.gov (United States)

    ... niacinamide), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B12 (cyanocobalamin), and folic acid. However, some products do ... for dandruff, depression, diabetic nerve pain, enhancing immune function, improving athletic performance, tongue infections, gray hair, headache, ...

  10. ACID ROCK DRAINAGE

    Directory of Open Access Journals (Sweden)

    Anca Ionce

    2010-10-01

    Full Text Available Acid rock drainage (ARD is an particularly important aspect for the evaluation of the decantation ponds’ safety, and which has been only once taken into consideration at the Tarnicioara decantation pond, year 2002, as a consequence of the apparition of a strong seepage on the deposit’s dump, that has chemically de-purified the water from the river Brateasa. We have observed ARD, which implies the release of acid solutions from the mining sterile deposits, from the underground mining works and from the quarries, in the following tailings dams: Tarnicioara, Valea Strajii, Poarta Veche- which served Tarniţa Preparation Enterprise and in the Dealu Negru and Paraul Cailor ponds- which, at their time served Fundu Moldovei Preparation Enterprise, both during the period of their functioning and the period after their closure. For the decantation pond Dumitrelu which served the Calimani preparation enterprise, acid seepages from the deposit were mentioned in a study made by SC ICPM SA Baia Mare in 1993. Subsequently to the closure of the objective such seepage did not take place anymore. Instead, by raining, there is a frequent plant sterile dragging from the contour retaining wall down to the trouble pond, situated upstream.

  11. Role of Amine Functionality for CO2 Chemisorption on Silica.

    Science.gov (United States)

    Hahn, Maximilian W; Jelic, Jelena; Berger, Edith; Reuter, Karsten; Jentys, Andreas; Lercher, Johannes A

    2016-03-01

    The mechanism of CO2 adsorption on primary, secondary, and bibasic aminosilanes synthetically functionalized in porous SiO2 was qualitatively and quantitatively investigated by a combination of IR spectroscopy, thermogravimetry, and quantum mechanical modeling. The mode of CO2 adsorption depends particularly on the nature of the amine group and the spacing between the aminosilanes. Primary amines bonded CO2 preferentially through the formation of intermolecular ammonium carbamates, whereas CO2 was predominantly stabilized as carbamic acid, when interacting with secondary amines. Ammonium carbamate formation requires the transfer of the carbamic acid proton to a second primary amine group to form the ammonium ion and hence two (primary) amine groups are required to bind one CO2 molecule. The higher base strength of secondary amines enables the stabilization of carbamic acid, which is thereby hindered to interact further with nearby amine functions, because their association with Si-OH groups (either protonation or hydrogen bonding) does not allow further stabilization of carbamic acid as carbamate. Steric hindrance of the formation of intermolecular ammonium carbamates leads to higher uptake capacities for secondary amines functionalized in porous SiO2 at higher amine densities. In aminosilanes possessing a primary and a secondary amine group, the secondary amine group tends to be protonated by Si-OH groups and therefore does not substantially interact with CO2. PMID:26700549

  12. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    OpenAIRE

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  13. Retinoic acid and cancer treatment

    OpenAIRE

    Chen, Mei-Chih; Hsu, Shih-Lan; Lin, Ho; Yang, Tsung-Ying

    2014-01-01

    Retinoic acid which belongs to the retinoid class of chemical compounds is an important metabolite of vitamin A in diets. It is currently understood that retinoic acid plays important roles in cell development and differentiation as well as cancer treatment. Lung, prostate, breast, ovarian, bladder, oral, and skin cancers have been demonstrated to be suppressed by retinoic acid. Our results also show that low doses and high doses of retinoic acid may respectively cause cell cycle arrest and a...

  14. Biological properties of lipoic acid

    Directory of Open Access Journals (Sweden)

    Anna Bilska

    2002-06-01

    Full Text Available Lipoic acid is a prostetic group of H-protein of the glycine cleavage system and the dihydrolipoamide acyltransferases (E2 of the pyruvate, alpha-ketoglutarate and branched-chain alpha-keto acid dehydrogenase complexes. Lipoic acid and its reduced form, dihydrolipoic acid, reacts with oxygen reactive species. This paper reviews the beneficial effects in oxidative stress models or clinical conditions.

  15. Sedimentation of sulfuric acid in acid tars from current production

    Energy Technology Data Exchange (ETDEWEB)

    Denisova, T.L.; Frolov, A.F.; Aminov, A.N.; Novosel' tsev, S.P.

    1987-09-01

    Acid tars obtained in treating T-750, KhF-12, and I-8A oils were investigated for purposes of recovering sulfuric acid and asphalt binders from the compositions and of determining the effects of storage time on the recovery. The consumption and sedimentation levels of sulfuric acid during storage for different periods and at different temperatures were assessed. The characteristics of an asphalt binder obtained by neutralizing acid tar with a paste consisting of asphalts from deasphalting operations and slaked lime, followed by oxidation of the mixture with atmospheric air, were determined. The sulfuric acid recovered in the settling process could be burned in order to purify it of organic contaminants.

  16. Acids and bases solvent effects on acid-base strenght

    CERN Document Server

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  17. An Umbrella for Acid Rain.

    Science.gov (United States)

    Randal, Judith

    1979-01-01

    The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

  18. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B;

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation...

  19. Pantothenic acid biosynthesis in zymomonas

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

    2014-07-01

    Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

  20. Acid Rain Limits Global Warming

    Institute of Scientific and Technical Information of China (English)

    Will Knight; 张林玲

    2004-01-01

    @@ Acid rain restricts global warming by reducing methane① emissions from natural wetland areas, suggests a global climate study. Acid rain is the result of industrial pollution,which causes rainwater to carry small quantities of acidic compoumds② such as sulphuric and nitric acid③. Contaminated rainwater can upset rivers and lakes, killing fish and other organisms and also damage plants, trees and buildings.

  1. Self-neutralizing well acidizing

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, E.A.; Scheuerman, R.F.

    1974-07-30

    A process for acidizing a subterranean region by contacting it with an acidic solution is improved by dissolving in the solution a pH-increasing reactant that subsequently adjusts the pH of the solution to a selected relatively neutral value. Urea is an example of the acid neutralizer. (10 claims)

  2. Ionic liquid supported acid-catalysed esterification of lauric acid

    International Nuclear Information System (INIS)

    Ionic Liquid (IL) based on 1-n-butyl-3-methylimidazolium bis(trifluoro methylsulfonyl)imide (BMI.NTf2) under acidic condition was used as catalyst for the esterification reaction of fatty acid. Various acids namely sulphuric acid, perchloric acid, p-toulene sulphonic acid and various chloride salts such as zinc chloride (ZnCl2) and iron (III) chloride (FeCl3) immobilized in ionic liquid BMI.NTf2 gave acidic ILs. These acidic ILs were tested as catalysts for esterification reactions. Esterification of alcohol (methanol) with fatty acid (lauric acid) using ionic liquid BMI.NTf2 combined with H2SO4 (BMI.NTf2(H2SO4)) gave high activity (>85 %) and selectivity (100 %) observed over a period of 2 hours reaction with reaction temperature 70 degree Celsius. The ester became easily separated due to IL forming biphasic with product after the reaction where ester accumulated as the upper phase and IL with water produced after reaction at lower phase. Catalytic activities comparison also be studied between acidic ionic liquid BMI.NTf2 with acidic ionic liquid ChCl.2ZnCl2 and conventional acid catalyst. These ILs were characterised by using FTIR, NMR and TGA. Results from FTIR were showed no significant difference between ILs with ILs in acidic condition. The TGA curve show BMI.NTf2 thermals decomposition is ≥400 degree Celsius but when BMI.NTf2 combination with H2SO4, TGA curve show weight loss increase and becomes unstable. The advantages of ILs as catalyst are clean process and green chemistry due to its behaviour such as non-volatile, no loss of solvent through evaporation and reduced environmentally impact. This ILs-catalyst system can be recycle for further reaction. (author)

  3. Invasive cleavage of nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2002-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  4. Invasive cleavage of nucleic acids

    Science.gov (United States)

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    1999-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  5. Tested Demonstrations: Color Oscillations in the Formic Acid-Nitric Acid-Sulfuric Acid System.

    Science.gov (United States)

    Raw, C. J. G.; And Others

    1983-01-01

    Presented are procedures for demonstrating the production of color oscillations when nitric acid is added to a formic acid/concentrated sulfuric acid mixture. Because of safety considerations, "Super-8" home movie of the color changes was found to be satisfactory for demonstration purposes. (JN)

  6. Polyunsaturated fatty acids and inflammation

    Directory of Open Access Journals (Sweden)

    Calder Philip C.

    2004-01-01

    Full Text Available The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and so available for eicosanoid production. Thus, n-3 polyunsaturated fatty acids act as arachidonic acid antagonists. Components of both natural and acquired immunity, including the production of key inflammatory cytokines, can be affected by n-3 polyunsaturated fatty acids. Although some of the effects of n-3 fatty acids may be brought about by modulation of the amount and types of eicosanoids made, it is possible that these fatty acids might elicit some of their effects by eicosanoid-independent mechanisms. Such n-3 fatty acid-induced effects may be of use as a therapy for acute and chronic inflammation, and for disorders that involve an inappropriately-activated immune response.

  7. Waste acid detoxification and reclamation

    International Nuclear Information System (INIS)

    Economically feasible processes that reduce the volume, quantity, and toxicity of metal-bearing waste acids by reclaiming, reusing, and recycling spent acids and metal salts are being developed and demonstrated. The acids used in the demonstrations are generated during metal-finishing operations used in nuclear fuel fabrication; HF-HNO3, HNO3, and HNO3-H2SO4 wastes result from Zr etching, Cu stripping, and chemical milling of U. At discharge, wastes contain high concentrations of acid and one major metal impurity. The waste minimization process used to reclaim acid from these three streams incorporates three processes for acid regeneration and reclamation. Normally, HNO3 remains in the bottoms when an aqueous acid solution is distilled; however, in the presence of H2SO4, HNO3 will distill to the overhead stream. In this process, nitrates and fluorides present as free acid and metal salts can be reclaimed as acid for recycle to the metal-finishing processes. Uranium present in the chemical milling solution can be economically recovered from distillation bottoms and refined. Using acid distillation, the volume of chemical milling solution discharged as waste can be reduced by as much as 60% depending on the H2SO4 concentration. A payback period of 2.2 years has been estimated for this process. The development and demonstration of precipitation and distillation processes for detoxification and reclamation of waste acid is supported by the US Department of Energy's Hazardous Waste Remedial Actions Program (HAZWRAP)

  8. Labeled bile acids

    International Nuclear Information System (INIS)

    A general short procedure for the introduction of 13C to the side chain of bile acids is described. Suitable (Z)-pregn-17(20)-enes are key intermediates, while the isotope is introduced by an ene reaction with [1,2,3-13C3]-methyl propiolate. For the labeling with tritium, the unlabeled product of the ene synthesis, a Δsup(5,16,22)-triene was saturated selectively at 16,17 and 22,23 with tritium gas. (author)

  9. N-(4-Isocyanophenylsuccinamic acid

    Directory of Open Access Journals (Sweden)

    Lauren E. Burnham

    2012-07-01

    Full Text Available In the crystal structure of the title compound, C11H10N2O3, inversion-related molecules are connected by pairs of O—H...O hydrogen bonds. With the exception of the atoms in the carboxylic acid group, the non-H atoms are roughly coplanar with a maximum deviation from the mean plane of 0.270 (1 Å for the C atom to which the carboxylic group is attached. The C atom of the carboxylic group lies 1.730 (2 Å from the mean plane.

  10. Nucleic Acid Vaccines

    Institute of Scientific and Technical Information of China (English)

    LU Shan

    2004-01-01

    @@ Anew method of immunization was discovered in the early 1990s. Several research groups independently demonstrated that direct inoculation of DNA plasmids coding for a specific protein antigen could elicit immune responses against that antigen[1-4].Since in theory the mRNA molecules also have the potential to be translated into the protein antigen, this vaccination approach was officially named by WHO as the nucleic acid vaccination even though the term DNA vaccine has been used more commonly in the literature. This novel approach is considered the fourth generation of vaccines after live attenuated vaccines, killed or inactivated vaccines and recombinant protein based subunit vaccines.

  11. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    OpenAIRE

    B. Syama Sundar; P.S.Radhakrishna murti

    2014-01-01

    Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation wi...

  12. Cryoprotection from lipoteichoic acid

    Science.gov (United States)

    Rice, Charles V.; Middaugh, Amy; Wickham, Jason R.; Friedline, Anthony; Thomas, Kieth J.; Johnson, Karen; Zachariah, Malcolm; Garimella, Ravindranth

    2012-10-01

    Numerous chemical additives lower the freezing point of water, but life at sub-zero temperatures is sustained by a limited number of biological cryoprotectants. Antifreeze proteins in fish, plants, and insects provide protection to a few degrees below freezing. Microbes have been found to survive at even lower temperatures, and with a few exceptions, antifreeze proteins are missing. Survival has been attributed to external factors, such as the high salt concentration of brine veins and adhesion to particulates or ice crystal defects. We have discovered an endogenous cryoprotectant in the cell wall of bacteria, lipoteichoic acid biopolymers. Adding 1% LTA to bacteria cultures immediately prior to freezing provides 50% survival rate, similar to the results obtained with 1% glycerol. In the absence of an additive, bacterial survival is negligible as measured with the resazurin cell viability assay. The mode of action for LTA cryoprotection is unknown. With a molecular weight of 3-5 kDa, it is unlikely to enter the cell cytoplasm. Our observations suggest that teichoic acids could provide a shell of liquid water around biofilms and planktonic bacteria, removing the need for brine veins to prevent bacterial freezing.

  13. Growth of nitric acid hydrates on thin sulfuric acid films

    Science.gov (United States)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-05-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1 - 3 × 10-4 Torr H2O and 1 - 2.5 × 10-6 Torr HNO3) and subjected to cooling and heating cycles. FTIR spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  14. Growth of nitric acid hydrates on thin sulfuric acid films

    Science.gov (United States)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-01-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  15. Caro's acid - its introduction to uranium acid leaching in Australia

    International Nuclear Information System (INIS)

    After extensive testing and plant trials to establish the benefits of Caro's acid (H2SO5) as an alternative oxidant, Queensland Mines Limited decided to replace pyrolusite with Caro's acid in its acid leach uranium treatment plant at Nabarlek. The decision was based on the reagent savings and environmental gains associated with the removal of manganese from the process liquors, as well as the labour savings and improved oxidation reduction potential control possible in leaching using the Caro's acid system. Some changes in operating parameters were necessary with the introduction of Caro's acid to the treatment plant. Operating results have confirmed the relationship between oxidant demand and uranium content of ore established during the trials. Acid savings have been as predicted from the plant trials. The major saving has been of hydrated lime required for tailings neutralisation

  16. Solid acid catalysis from fundamentals to applications

    CERN Document Server

    Hattori, Hideshi

    2014-01-01

    IntroductionTypes of solid acid catalystsAdvantages of solid acid catalysts Historical overviews of solid acid catalystsFuture outlookSolid Acids CatalysisDefinition of acid and base -Brnsted acid and Lewis acid-Acid sites on surfacesAcid strengthRole of acid sites in catalysisBifunctional catalysisPore size effect on catalysis -shape selectivity-Characterization of Solid Acid Catalysts Indicator methodTemperature programmed desorption (TPD) of ammoniaCalorimetry of adsorption of basic moleculesInfrare

  17. Amino Acid Decarboxylase Activity of Some Lactic Acid Bacteria

    OpenAIRE

    Pelin ERTÜRKMEN; Turhan, İlkay; Öner, Zübeyde

    2015-01-01

    Microorganisms which have decarboxylase activity can form biogenic amine by enzymatic decarboxylation of amino acids in foods. Histamine poisoning results from consumption of foods typically certain types of fish and cheeses that contain unusually high levels of histamine. Therefore, decarboxylase activity is an important problem at the selection of lactic acid bacteria as a starter culture in fermented products. In this study, decarboxylase activities of 161 lactic acid bacteria (LAB) strain...

  18. Synthesis of stearic acid triethanolamine ester over solid acid catalysts

    Institute of Scientific and Technical Information of China (English)

    Tao Geng; Qiu Xiao Li; Ya Jie Jiang; Wei Wang

    2010-01-01

    The synthesis of stearic acid triethanolamine ester over solid acid catalysts was investigated.The results showed that the catalytic activity and selectivity of zirconium sulfate supported on SBA-15(6)(pore diameter 6 nm)is better than that of commonly used hypophosphorous acid,zirconium sulfate supported on MCM-41 and zirconium sulfate supported on SBA-15(9)(pore diameter 9 nm).

  19. Bile acid interactions with cholangiocytes

    Institute of Scientific and Technical Information of China (English)

    Xuefeng Xia; Heather Francis; Shannon Glaser; Gianfranco Alpini; Gene LeSage

    2006-01-01

    Cholangiocytes are exposed to high concentrations of bile acids at their apical membrane. A selective transporter for bile acids, the Apical Sodium Bile Acid Cotransporter (ASBT) (also referred to as Ibat; gene name Slc10a2)is localized on the cholangiocyte apical membrane. On the basolateral membrane, four transport systems have been identified (t-ASBT, multidrug resistance (MDR)3,an unidentified anion exchanger system and organic solute transporter (Ost) heteromeric transporter, OstαOstβ. Together, these transporters unidirectionally move bile acids from ductal bile to the circulation. Bile acids absorbed by cholangiocytes recycle via the peribiliaryplexus back to hepatocytes for re-secretion into bile.This recycling of bile acids between hepatocytes and cholangiocytes is referred to as the cholehepatic shunt pathway. Recent studies suggest that the cholehepatic shunt pathway may contribute in overall hepatobiliary transport of bile acids and to the adaptation to chronic cholestasis due to extrahepatic obstruction. ASBT is acutely regulated by an adenosine 3', 5'-monophosphate (cAMP)-dependent translocation to the apical membrane and by phosphorylation-dependent ubiquitination and proteasome degradation. ASBT is chronically regulated by changes in gene expression in response to biliary bile acid concentration and inflammatory cytokines.Another potential function of cholangiocyte ASBT is to allow cholangiocytes to sample biliary bile acids in order to activate intracellular signaling pathways. Bile acids trigger changes in intracellular calcium, protein kinase C (PKC), phosphoinositide 3-kinase (PI3K), mitogenactivated protein (MAP) kinase and extracellular signalregulated protein kinase (ERK) intracellular signals.Bile acids significantly alter cholangiocyte secretion,proliferation and survival. Different bile acids have differential effects on cholangiocyte intracellular signals,and in some instances trigger opposing effects on cholangiocyte secretion

  20. Molecular Simulation of Naphthenic Acid Removal on Acidic Catalyst Ⅱ. Experimental results of catalytic decarboxylation over acidic catalysts

    Institute of Scientific and Technical Information of China (English)

    Fu Xiaoqin; Tian Songbai; Hou Shuandi; Longjun; Wang Xieqing

    2008-01-01

    The energy barriers of thermal decarboxylation reactions of petroleum acids and catalytic decarboxylation reactions of Br(o)nsted acid and Lewis acid were analyzed using molecular simulation technology.Compared with thermal decarboxylation reactions of petroleum acids, the decarboxylation reactions by acid catalysts were easier to occur. The decarboxylaton effect by Lewis acid was better than Br(o)nsted acid. The mechanisms of catalytic decarboxylation over acid catalyst were also verified by experiments on a fixed bed and a fluidized bed, the experimental results showed that the rate of acid removal could reach up to 97% over the acidic catalyst at a temperature above 400℃.