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Sample records for benzoapyrene diol epoxide

  1. Benzo(a)pyrene diol epoxides as intermediates in nucleic acid binding in vivo and in vitro

    DEFF Research Database (Denmark)

    Weinstein, I.B.; Jeffrey, A.M.; Jennette, K.W.

    1976-01-01

    Evidence has been obtained that a specific isomer of a diol epoxide derivative of benzo(a)pyrene, (+/-)-7 beta,8alpha-dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene, is an intermediate in the binding of benzo(a)pyrene to RNA in cultured bovine bronchial mucosa. An adduct is for...

  2. Benzo(a)pyrene diol epoxides as intermediates in nucleic acid binding in vitro and in vivo.

    Science.gov (United States)

    Weinstein, I B; Jeffrey, A M; Jennette, K W; Blobstein, S H; Harvey, R G; Harris, C; Autrup, H; Kasai, H; Nakanishi, K

    1976-08-13

    Evidence has been obtained that a specific isomer of a diol epoxide derivative of benzo(a)pyrene, (+/-)-7 beta,8alpha-dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene, is an intermediate in the binding of benzo(a)pyrene to RNA in cultured bovine bronchial mucosa. An adduct is formed between position 10 of this derivative and the 2-amino group of guanine.

  3. Further characterization of benzo[a]pyrene diol-epoxide (BPDE)-induced comet assay effects.

    Science.gov (United States)

    Bausinger, Julia; Schütz, Petra; Piberger, Ann Liza; Speit, Günter

    2016-03-01

    The present study aims to further characterize benzo[a]pyrene diol-epoxide (BPDE)-induced comet assay effects. Therefore, we measured DNA effects by the comet assay and adduct levels by high-performance liquid chromatography (HPLC) in human lymphocytes and A549 cells exposed to (±)-anti-benzo[a]pyrene-7,8-diol 9,10-epoxide [(±)-anti-BPDE] or (+)-anti-benzo[a]pyrene-7,8-diol 9,10-epoxide [(+)-anti-BPDE]. Both, the racemic form and (+)-anti-BPDE, which is the most relevant metabolite with regard to mutagenicity and carcinogenicity, induced DNA migration in cultured lymphocytes in the same range of concentrations to a similar extent in the alkaline comet assay after exposure for 2h. Nevertheless, (+)-anti-BPDE induced significantly enhanced DNA migration after 16 and 18h post-cultivation which was not seen in response to (±)-anti-BPDE. Combination of the comet assay with the Fpg (formamidopyrimidine-DNA glycosylase) protein did not enhance BPDE-induced effects and thus indicated the absence of Fpg-sensitive sites (oxidized purines, N7-guanine adducts, AP-sites). The aphidicolin (APC)-modified comet assay suggested significant excision repair activity of cultured lymphocytes during the first 18h of culture after a 2 h-exposure to BPDE. In contrast to these repair-related effects measured by the comet assay, HPLC analysis of stable adducts did not reveal any significant removal of (+)-anti-BPDE-induced adducts from lymphocytes during the first 22h of culture. On the other hand, HPLC measurements indicated that A549 cells repaired about 70% of (+)-anti-BPDE-induced DNA-adducts within 22h of release. However, various experiments with the APC-modified comet assay did not indicate significant repair activity during this period in A549 cells. The conflicting results obtained with the comet assay and the HPLC-based adduct analysis question the real cause for BPDE-induced DNA migration in the comet assay and the reliability of the APC-modified comet assay for the

  4. Formation of diastereomeric benzo[a]pyrene diol epoxide-guanine adducts in p53 gene-derived DNA sequences.

    Science.gov (United States)

    Matter, Brock; Wang, Gang; Jones, Roger; Tretyakova, Natalia

    2004-06-01

    G --> T transversion mutations in the p53 tumor suppressor gene are characteristic of smoking-related lung tumors, suggesting that these genetic changes may result from exposure to tobacco carcinogens. It has been previously demonstrated that the diol epoxide metabolites of bay region polycyclic aromatic hydrocarbons present in tobacco smoke, e.g., benzo[a]pyrene diol epoxide (BPDE), preferentially bind to the most frequently mutated guanine nucleotides within p53 codons 157, 158, 248, and 273 [Denissenko, M. F., Pao, A., Tang, M., and Pfeifer, G. P. (1996) Science 274, 430-432]. However, the methodology used in that work (ligation-mediated polymerase chain reaction in combination with the UvrABC endonuclease incision assay) cannot establish the chemical structures and stereochemical identities of BPDE-guanine lesions. In the present study, we employ a stable isotope-labeling HPLC-MS/MS approach [Tretyakova, N., Matter, B., Jones, R., and Shallop, A. (2002) Biochemistry 41, 9535-9544] to analyze the formation of diastereomeric N(2)-BPDE-dG lesions within double-stranded oligodeoxynucleotides representing p53 lung cancer mutational hotspots and their surrounding DNA sequences. (15)N-labeled dG was placed at defined positions within DNA duplexes containing 5-methylcytosine at all physiologically methylated sites, followed by (+/-)-anti-BPDE treatment and enzymatic hydrolysis of the adducted DNA to 2'-deoxynucleosides. Capillary HPLC-ESI(+)-MS/MS was used to establish the amounts of (-)-trans-N(2)-BPDE-dG, (+)-cis-N(2)-BPDE-dG, (-)-cis-N(2)-BPDE-dG, and (+)-trans-N(2)-BPDE-dG originating from the (15)N-labeled bases. We found that all four N(2)-BPDE-dG diastereomers were formed preferentially at the methylated CG dinucleotides, including the frequently mutated p53 codons 157, 158, 245, 248, and 273. The contributions of individual diastereomers to the total adducts number at a given site varied between 70.8 and 92.9% for (+)-trans-N(2)-BPDE-dG, 5.6 and 16.7% for

  5. DNA polymerase eta participates in the mutagenic bypass of adducts induced by benzo[a]pyrene diol epoxide in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Alden C Klarer

    Full Text Available Y-family DNA-polymerases have larger active sites that can accommodate bulky DNA adducts allowing them to bypass these lesions during replication. One member, polymerase eta (pol eta, is specialized for the bypass of UV-induced thymidine-thymidine dimers, correctly inserting two adenines. Loss of pol eta function is the molecular basis for xeroderma pigmentosum (XP variant where the accumulation of mutations results in a dramatic increase in UV-induced skin cancers. Less is known about the role of pol eta in the bypass of other DNA adducts. A commonly encountered DNA adduct is that caused by benzo[a]pyrene diol epoxide (BPDE, the ultimate carcinogenic metabolite of the environmental chemical benzo[a]pyrene. Here, treatment of pol eta-deficient fibroblasts from humans and mice with BPDE resulted in a significant decrease in Hprt gene mutations. These studies in mammalian cells support a number of in vitro reports that purified pol eta has error-prone activity on plasmids with site-directed BPDE adducts. Sequencing the Hprt gene from this work shows that the majority of mutations are G>T transversions. These data suggest that pol eta has error-prone activity when bypassing BPDE-adducts. Understanding the basis of environmental carcinogen-derived mutations may enable prevention strategies to reduce such mutations with the intent to reduce the number of environmentally relevant cancers.

  6. Serum Level of Antibody against Benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA Adducts in People Dermally Exposed to PAHs

    Directory of Open Access Journals (Sweden)

    Lenka Borska

    2014-01-01

    Full Text Available Some specific antibodies indicate the presence of antigenic structures on DNA (DNA adducts that can play an important role in the process of mutagenesis and/or carcinogenesis. They indicate the presence of increased genotoxic potential (hazard prior to the formation of disease (primary prevention. The present study was focused on the serum level of benzo[a]pyrene 7,8-diol-9,10-epoxide-DNA adducts antibodies (anti-BPDE-DNA in psoriatic patients (n=55 dermally exposed to different levels of polycyclic aromatic hydrocarbons (PAHs. The general goal of the study was to contribute to better understanding of the value of the assumed biomarker (anti-BPDE-DNA for evaluation of the organism's answer to genotoxic exposure to PAHs. Elevated level of exposure to PAHs resulted in the increased level of anti-BPDE-DNA. However, almost all levels of anti-BPDE-DNA ranged within the field of low values. Both variants of GT (CCT-3% and CCT-5% induced higher expression of anti-BPDE-DNA in the group of nonsmokers. Significant relations between the level of anti-BPDE-DNA and PASI score, total duration of the therapy, or time of UVR exposure were not found. Further studies are needed to reduce interpretation uncertainty of this promising bioindicator.

  7. Serum Level of Antibodies (IgG, IgM Against Benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA Adducts in Children Dermatologically Exposed to Coal Tar

    Directory of Open Access Journals (Sweden)

    Pavel Borský

    2017-06-01

    Full Text Available Crude coal tar (CCT contains polycyclic aromatic hydrocarbons (PAHs. Benzo[a]pyrene (BaP is metabolized into a highly reactive metabolite benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE that is able to bind to DNA and creates BPDE-DNA adducts. Adducted DNA becomes immunogenic and induces immune response by production of antibodies against BPDE-DNA adducts (Ab-BPDE-DNA. Circulating Ab-BPDE-DNA was proposed as potential biomarker of genotoxic exposure to BaP (PAHs. Goeckerman therapy (GT of psoriasis uses dermal application of CCT ointment (PAHs. In presented study (children with psoriasis treated by GT; n = 19 the therapy significantly increased the level of Ab-BPDE-DNA (EI = 0.29/0.19–0.34 vs. 0.31/0.25–0.40; median/lower–upper quartile; p < 0.01. The results support the idea of Ab-BPDE-DNA level as a possible tentative indicator of exposure, effects and susceptibility of the organism to the exposure of BaP (PAHs.

  8. The role of hRev7, the accessory subunit of hPolζ, in translesion synthesis past DNA damage induced by benzo[a]pyrene diol epoxide (BPDE

    Directory of Open Access Journals (Sweden)

    Maher Veronica M

    2010-12-01

    Full Text Available Abstract Background DNA polymerase zeta (Polζ is a specialized DNA polymerase that, unlike classical replicative polymerases, is capable of replicating past DNA lesions, i.e. of performing translesion synthesis (TLS. The catalytic subunit of hPolζ, hRev3, has been shown to play a critical role in DNA damage-induced mutagenesis in human cells, but less is known about the role of hRev7, the accessory subunit of hPolζ, in such mutagenesis. To address this question, we recently generated human fibroblasts with very significantly reduced levels of hRev7 protein and demonstrated that hRev7 is required to protect cells from ultraviolet(254 nm (UV radiation-induced cytotoxicity and mutagenesis (McNally et al., DNA Repair 7 (2008 597-604. The goal of the present study was to determine whether hRev7 is similarly involved in the tolerance of DNA damage induced by benzo[a]pyrene diol epoxide (BPDE, the reactive form of the widespread environmental carcinogen benzo[a]pyrene. Methods To determine whether hRev7 also plays a role in protecting human cells from the cytotoxicity and mutagenesis induced by benzo[a]pyrene diol epoxide (BPDE, cell strains with reduced hRev7 were compared to their parental strain and a vector control strain for the effect of BPDE on cell survival, induction of mutations, and the ability to progress through the cell cycle. Results The results show that cell strains with reduced hRev7 are more sensitive to the cytotoxic effect of BPDE than the control strains, and progress through S-phase at a slower rate than the control cells following BPDE treatment, indicating that hRev7, and likely hPolζ, is required for efficient bypass of BPDE-induced DNA lesions. However, neither the frequency nor kinds of mutations induced by BPDE in cells with reduced hRev7 differ significantly from those induced in the control strains, suggesting that hPolζ is not essential for inserting nucleotides opposite BPDE-induced DNA damage. Conclusions Taken

  9. Reaction of a chemotherapeutic agent, 6-mercaptopurine, with a direct-acting, electrophilic carcinogen, benzo[a]pyrene-7,8-diol 9,10-epoxide.

    Science.gov (United States)

    MacLeod, M C; Stewart, E; Daylong, A; Lew, L K; Evans, F E

    1991-01-01

    The chemotherapeutic agent 6-mercaptopurine (6-MP) has been shown to react covalently with the ultimate carcinogenic metabolite of benzo[a]pyrene, 7-r,8-t-dihydroxy-9-t,10-t-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE), in aqueous solution, forming a single adduct. NMR studies of the HPLC-purified product were consistent with its identification as 10(S)-(6'-mercaptopurinyl)-7,8,9-trihydroxy-7,8,9,10- tetrahydrobenzo[a]pyrene. Reaction kinetics were analyzed by using both HPLC separation of the products formed and a spectrophotometric assay for adduct formation. A simple model in which direct reaction between 6-MP and BPDE takes place without formation of a physical complex was found to adequately predict the dependence of product ratios on 6-MP concentration. Variations in the observed rate constant for this reaction with changes in temperature, pH, and buffer concentration were determined and compared to the effects of these variables on the observed rate constant for BPDE hydrolysis. In each case, the processes were affected quite differently, suggesting that different rate-determining steps are involved. The data suggest that the reaction mechanism involves SN2 attack of the anion of 6-MP, formed by ionization of the sulfhydryl group, on carbon 10 of BPDE, resulting in a trans-9,10 reaction product.

  10. hREV3 is essential for error-prone translesion synthesis past UV or benzo[a]pyrene diol epoxide-induced DNA lesions in human fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Li Ziqiang; Zhang Hong; McManus, Terrence P.; McCormick, J. Justin; Lawrence, Christopher W.; Maher, Veronica M

    2002-12-29

    In S. cerevisiae, the REV3 gene, encoding the catalytic subunit of polymerase zeta, is involved in translesion synthesis and required for the production of mutations induced by ultraviolet radiation (UV) photoproducts and other DNA fork-blocking lesions, and for the majority of spontaneous mutations. To determine whether hREV3, the human homolog of yeast REV3, is similarly involved in error-prone translesion synthesis past UV photoproducts and other lesions that block DNA replication, an hREV3 antisense construct under the control of the TetP promoter was transfected into an infinite life span human fibroblast cell strain that expresses a high level of tTAk, the activator of that promoter. Three transfectant strains expressing high levels of hREV3 antisense RNA were identified and compared with their parental cell strain for sensitivity to the cytotoxic and mutagenic effects of UV. The three hREV3 antisense-expressing cell strains were not more sensitive than the parental strain to the cytotoxic effect of UV, but the frequency of mutants induced by UV in their HPRT gene was significantly reduced, i.e. to 14% that of the parent. Two of these hREV3 antisense-expressing cell strains were compared with the parental strain for sensitivity to ({+-})-7{beta},8{alpha}-dihydroxy-9{alpha},10{alpha}-epoxy-7,8,9,10-tetrahydro= benzo[a]pyrene (BPDE). They were not more sensitive than the parent strain to the cytotoxic effect of BPDE, but the frequency of mutants induced was significantly reduced, i.e. in one strain, to 17% that of the parent, and in the other, to 24%. DNA sequencing showed that the kinds of mutations induced by BPDE in the parental and the derivative strains did not differ and were similar to those found previously with finite life span human fibroblasts. The data strongly support the hypothesis that hRev3 plays a critical role in the induction of mutations by UV or BPDE. Because the level of hRev3 protein in human fibroblasts is below the level of antibody

  11. In vitro metabolism of benzo[a]pyrene-7,8-dihydrodiol and dibenzo[def,p]chrysene-11,12 diol in rodent and human hepatic microsomes

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jordan N.; Mehinagic, Denis; Nag, Subhasree; Crowell, Susan R.; Corley, Richard A.

    2017-03-01

    Polycyclic aromatic hydrocarbons (PAHs) are contaminants that are ubiquitously found in the environment, produced through combustion of organic matter or petrochemicals, and many of which are procarcinogens. The prototypic PAH, benzo[a]pyrene (B[a]P) and the highly carcinogenic dibenzo[def,p]chrysene (DBC) are metabolically activated by isoforms of the P450 enzyme superfamily producing benzo[a]pyrene-7,8-dihydrodiol (B[a]P diol), dibenzo[def,p]chrysene-11,12 diol (DBC diol). Each of these diols can be further metabolized by cytochrome P450 enzymes to highly reactive diol-epoxide metabolites that readily react with DNA or by phase II conjugation facilitating excretion. To complement prior in vitro metabolism studies with parent B[a]P and DBC, both phase I metabolism and phase II glucuronidation of B[a]P diol and DBC diol were measured in hepatic microsomes from female B6129SF1/J mice, male Sprague-Dawley rats, and female humans. Metabolic parameters, including intrinsic clearance and Michaelis-Menten kinetics were calculated from substrate depletion data. Mice and rats demonstrated similar B[a]P diol phase I metabolic rates. Compared to rodents, human phase I metabolism of B[a]P diol demonstrated lower overall metabolic capacity, lower intrinsic clearance at higher substrate concentrations (>0.14 µM), and higher intrinsic clearance at lower substrate concentrations (<0.07 µM). Rates of DBC diol metabolism did not saturate in mice or humans and were highest overall in mice. Higher affinity constants and lower capacities were observed for DBC diol glucuronidation compared to B[a]P diol glucuronidation; however, intrinsic clearance values for these compounds were consistent within each species. Kinetic parameters reported here will be used to extend physiologically based pharmacokinetic (PBPK) models to include the disposition of B[a]P and DBC metabolites in animal models and humans to support future human health risk assessments.

  12. Metabolic activation and DNA binding of benzo(a)pyrene in cultured human bronchus

    DEFF Research Database (Denmark)

    Yang, Shen K.; Gelboin, Harry V.; Trump, Benjamin F.

    1977-01-01

    . The predominant metabolite formed by human bronchus from the (-)-trans-7,8-diol is found by high-pressure liquid chromatographic analysis to be the diol-epoxide r-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahy-drobenzo(a)pyrene. The results suggest that this diol-epoxide is the major benzo(a)pyrene metabolite bound...

  13. Human hair follicle benzo(a)pyrene and benzo(a)pyrene 7, 8-diol metabolism: effect of exposure to a coal tar-containing shampoo

    Energy Technology Data Exchange (ETDEWEB)

    Merk, H.F.; Mukhtar, H.; Kaufmann, I.; Das, M.; Bickers, D.R.

    1987-01-01

    Hair follicles are a readily available source of human epithelial tissue and offer an excellent system with which to study carcinogen metabolism in human populations. In this study hair follicles were employed to measure the metabolism of benzo(a)pyrene (BP), benzo(a)pyrene - 7,8-diol (BP 7,8-diol) and the enzyme mediated binding of /sup 3/H-BP to DNA. The effect of human exposure to a crude coal tar (CCT) - containing shampoo, a preparation rich in polycyclic aromatic hydrocarbons (PAHs on these parameters was also evaluated. It was found that aryl hydrocarbon hydroxylase (AHH) activity increased after use of the shampoo and enhancement of enzyme-mediated binding of BP to DNA was detected in most subjects. Hair follicles were shown to convert BP to several metabolic species and BP, 7,8-diol was also metabolised. Clotrimazole, a known inhibitor of the metabolism of BP was found to inhibit AHH and the metabolism of BP and BP 7,8-diol in human hair follicles, as were other imidazole compounds. The studies show that hair follicles represent an accessible tissue suitable for assessing the extent of PAH carcinogen metabolism in human subjects. Furthermore enzyme activity critical to cancer induction by PAHs was shown to be inducible following the use of a CCT-containing shampoo. Imidazole compounds were shown to be possible effective anti-carcinogens in human populations. 29 refs.

  14. Flow cytometric measurement of the metabolism of benzo[a]pyrene by mouse liver cells in culture

    International Nuclear Information System (INIS)

    Bartholomew, J.C.; Wade, C.G.; Dougherty, K.K.

    1984-01-01

    The metabolism of benzo[a]pyrene in individual cells was monitored by flow cytometry. The measurements are based on the alterations that occur in the fluorescence emission spectrum of benzo[a]pyrene when it is converted to various metabolites. Using present instrumentation the technique could easily detect 1x10 6 molecules per cells of benzo[a]pyrene and 1x10 7 molecules per cell of the diol epoxide. The analysis of C3H IOT 1/2 mouse fibroblasts growing in culture indicated that there was heterogeneity in the conversion of the parent compound into diol epoxide derivatives suggesting that some variation in sensitivity to transformation by benzo[a]pyrene may be due to differences in cellular metabolism. The technique allows sensitive detection of metabolites in viable cells, and provides a new approach to the study of factors that influence both metabolism and transformation. (orig.)

  15. The epoxide-diol pathway in the metabolism of vinylbital in rat and man

    NARCIS (Netherlands)

    Vermeulen, N P; Bakker, B H; Eylers, D; Breimer, D D

    1. In urine of rats given vinylbital (5-vinyl-5-(1'-methylbutyl)barbituric acid) i.p., unchanged vinylbital and its devinylated metabolite, 5-(1'-methylbutyl)barbituric acid, were identified. Rats synthetic 1',2'-epoxyvinylbital excreted the same compound as a major metabolite. No unchanged epoxide,

  16. BENZO[A]PYRENE AND ITS K-REGION DIOL INDUCE DNA DAMAGE IN C3H10T1/2C18 CELLS AS MEASURED BY THE ALKALINE SINGLE CELL GEL (COMET) ASSAY

    Science.gov (United States)

    160. Benzo[a]pyrene and its K-region diol induce DNA damage in C3HlOTl/2Cl8 cells as measured by the alkaline single cell gel (Comet) assay In a continuing series of studies on the genotoxicity ofK-region dihydrodiols of polycyclic aromatic hydrocarbons, we have repo...

  17. Metabolites of the PAH diol epoxide pathway and other urinary biomarkers of phenanthrene and pyrene in workers with and without exposure to bitumen fumes.

    Science.gov (United States)

    Lotz, Anne; Pesch, Beate; Dettbarn, Gerhard; Raulf, Monika; Welge, Peter; Rihs, Hans-Peter; Breuer, Dietmar; Gabriel, Stefan; Hahn, Jens-Uwe; Brüning, Thomas; Seidel, Albrecht

    2016-11-01

    This study investigates the diol epoxide pathway of phenanthrene (PHE) together with phenolic metabolites of PHE and pyrene (PYR) in workers with and without exposure to bitumen fumes. The metabolite concentrations were determined in urine samples collected from 91 mastic asphalt workers and 42 construction workers as reference group before and after shift. During shift, vapours and aerosols of bitumen were measured according to a German protocol in the workers' breathing zone. The median concentration of vapours and aerosols of bitumen in mastic asphalt workers was 6.3 mg/m 3 . Metabolite concentrations were highest in post-shift urines of smokers with bitumen exposure and showed an increase during shift. The Spearman correlations between the creatinine-adjusted concentrations of metabolites and vapours and aerosols of bitumen in non-smokers were weak (e.g. sum of Di-OH-PYR: 0.28) or negligible (e.g. 1,2-PHE-diol: 0.08; PHE-tetrol: 0.12). Metabolites from the diol epoxide pathway of PHE were excreted in higher concentrations than phenolic metabolites (post-shift, non-smoking asphalt workers: 1,2-PHE-diol 2.59 µg/g crea vs. sum of all OH-PHE 1.87 µg/g crea). 1,2-PHE-diol was weakly correlated with PHE-tetrol (Spearman coefficient 0.30), an endpoint of the diol epoxide pathway. By contrast, we found a close correlation between the sum of 1,6-DiOH-PYR and 1,8-DiOH-PYR with 1-OH-PYR (Spearman coefficient 0.76). Most urinary PAH metabolites were higher after shift in bitumen-exposed workers, although the association with bitumen was weak or negligible likely due to the small PAH content. The additional metabolites of PHE and PYR complete the picture of the complex metabolic pathways. Nevertheless, none of the PAH metabolites can be considered to be a specific biomarker for bitumen exposure.

  18. Inhibition of HIV-1 reverse transcriptase-catalyzed synthesis by intercalated DNA Benzo[a]Pyrene 7,8-Dihydrodiol-9,10-Epoxide adducts.

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    Parvathi Chary

    Full Text Available To aid in the characterization of the relationship of structure and function for human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT, this investigation utilized DNAs containing benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE-modified primers and templates as a probe of the architecture of this complex. BPDE lesions that differed in their stereochemistry around the C10 position were covalently linked to N (6-adenine and positioned in either the primer or template strand of a duplex template-primer. HIV-1 RT exhibited a stereoisomer-specific and strand-specific difference in replication when the BPDE-lesion was placed in the template versus the primer strand. When the C10 R-BPDE adduct was positioned in the primer strand in duplex DNA, 5 nucleotides from the 3΄ end of the primer terminus, HIV-1 RT could not fully replicate the template, producing truncated products; this block to further synthesis did not affect rates of dissociation or DNA binding affinity. Additionally, when the adducts were in the same relative position, but located in the template strand, similar truncated products were observed with both the C10 R and C10 S BPDE adducts. These data suggest that the presence of covalently-linked intercalative DNA adducts distant from the active site can lead to termination of DNA synthesis catalyzed by HIV-1 RT.

  19. 3,3′,4,4′,5-Pentachlorobiphenyl (PCB 126) Decreases Hepatic and Systemic Ratios of Epoxide to Diol Metabolites of Unsaturated Fatty Acids in Male Rats

    Science.gov (United States)

    Wu, Xianai; Yang, Jun; Morisseau, Christophe; Robertson, Larry W.; Hammock, Bruce; Lehmler, Hans-Joachim

    2016-01-01

    Disruption of the homeostasis of oxygenated regulatory lipid mediators (oxylipins), potential markers of exposure to aryl hydrocarbon receptor (AhR) agonists, such as 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), is associated with a range of diseases, including nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Here we test the hypothesis that PCB 126 exposure alters the levels of oxylipins in rats. Male Sprague-Dawley rats (5-weeks old) were treated over a 3-month period every 2 weeks with intraperitoneal injections of PCB 126 in corn oil (cumulative doses of 0, 19.8, 97.8, and 390 µg/kg b.w.; 6 injections total). PCB 126 treatment caused a reduction in growth rates at the highest dose investigated, a dose-dependent decrease in thymus weights, and a dose-dependent increase in liver weights. Liver PCB 126 levels increased in a dose-dependent manner, while levels in plasma were below or close to the detection limit. The ratios of several epoxides to diol metabolites formed via the cytochrome P450 (P450) monooxygenase/soluble epoxide hydrolase (sEH) pathway from polyunsaturated fatty acids displayed a dose-dependent decrease in the liver and plasma, whereas levels of oxylipins formed by other metabolic pathways were generally not altered by PCB 126 treatment. The effects of PCB 126 on epoxide-to-diol ratios were associated with an increased CYP1A activity in liver microsomes and an increased sEH activity in liver cytosol and peroxisomes. These results suggest that oxylipins are potential biomarkers of exposure to PCB 126 and that the P450/sEH pathway is a therapeutic target for PCB 126-mediated hepatotoxicity that warrants further attention. PMID:27208083

  20. hREV3 is essential for error-prone translesion synthesis past UV or benzo[a]pyrene diol epoxide-induced DNA lesions in human fibroblasts

    International Nuclear Information System (INIS)

    Li Ziqiang; Zhang Hong; McManus, Terrence P.; McCormick, J. Justin; Lawrence, Christopher W.; Maher, Veronica M.

    2002-01-01

    In S. cerevisiae, the REV3 gene, encoding the catalytic subunit of polymerase zeta, is involved in translesion synthesis and required for the production of mutations induced by ultraviolet radiation (UV) photoproducts and other DNA fork-blocking lesions, and for the majority of spontaneous mutations. To determine whether hREV3, the human homolog of yeast REV3, is similarly involved in error-prone translesion synthesis past UV photoproducts and other lesions that block DNA replication, an hREV3 antisense construct under the control of the TetP promoter was transfected into an infinite life span human fibroblast cell strain that expresses a high level of tTAk, the activator of that promoter. Three transfectant strains expressing high levels of hREV3 antisense RNA were identified and compared with their parental cell strain for sensitivity to the cytotoxic and mutagenic effects of UV. The three hREV3 antisense-expressing cell strains were not more sensitive than the parental strain to the cytotoxic effect of UV, but the frequency of mutants induced by UV in their HPRT gene was significantly reduced, i.e. to 14% that of the parent. Two of these hREV3 antisense-expressing cell strains were compared with the parental strain for sensitivity to (±)-7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE). They were not more sensitive than the parent strain to the cytotoxic effect of BPDE, but the frequency of mutants induced was significantly reduced, i.e. in one strain, to 17% that of the parent, and in the other, to 24%. DNA sequencing showed that the kinds of mutations induced by BPDE in the parental and the derivative strains did not differ and were similar to those found previously with finite life span human fibroblasts. The data strongly support the hypothesis that hRev3 plays a critical role in the induction of mutations by UV or BPDE. Because the level of hRev3 protein in human fibroblasts is below the level of antibody detection, it was not possible to demonstrate that the decrease in mutagenesis reflected decreased hRev3 protein. However, the conclusion is supported by the fact that in a similar study with a strain expressing a high level of antisense hREV1, a very similar result was obtained, i.e. UV or BPDE mutagenesis was virtually eliminated.

  1. Comparison of epoxide and free-radical mechanisms for activation of benzo[a]pyrene by Sprague-Dawley rat liver microsomes

    International Nuclear Information System (INIS)

    Selkirk, J.K.

    1980-01-01

    Coincubation of [6- 3 H]benzo[a]pyrene ([6- 3 H]BP) and [ 14 C]BP with SD rat liver microsomes produced metabolic profiles that showed that the C-6 of BP was not affected by formation of 4,5-dihydro-4,5-dihydroxy-BP, 7,8-dihydro-7,8-dihydroxy-BP, and 9,10-dihydro-9,10-dihydroxy-BP nor the 3- and 9-phenols of BP. Complete retention of tritium at C-6, except in the three quinones, confirmed the radical-cation model for formation of the 6-oxo-radical followed by oxidation to quinone. Epoxide formation at the carcinogenically active regions of BP appeared to biochemically isolate from 6-position activation and suggested that the microsomal epoxide pathway is unrelated to the radicalcation scheme. These molar ratios derived from double-label experiments reinforced the current literature that indicates the epoxide mechanism as the major pathway toward carcinogenic forms of BP

  2. TPX2 in malignantly transformed human bronchial epithelial cells by anti-benzo[a]pyrene-7,8-diol-9,10-epoxide

    International Nuclear Information System (INIS)

    Zhang Lijuan; Huang He; Deng Luyao; Chu Ming; Xu Lan; Fu Juanling; Zhu Yunlan; Zhang Xiuchun; Liu Shulin; Zhou Zongcan; Wang Yuedan

    2008-01-01

    In order to elucidate the function of the targeting protein for Xenopus kinesin-like protein 2 (Xklp2) (TPX2) in the malignant transformation of human bronchial epithelial cells induced by anti-benzo[a]pyrene-trans-7, 8-dihydrodiol-9, 10-epoxide (anti-BPDE), TPX2 was characterized in cells at both the gene and the protein levels. TPX2 was present at higher levels in 16HBE-C cells than in 16HBE cells as demonstrated by two-dimensional gel electrophoresis, immunocytochemistry, Western blot analysis and RT-PCR. TPX2 was also detected in lung squamous-cell carcinoma tissues by immunohistochemistry, but not in normal lung tissues. Depression of TPX2 by RNA interference in 16HBE-C cells led to a decrease in cell proliferation, S-phase cell cycle arrest and cell apoptosis. Abnormal TPX2 tyrosine phosphorylation was detected in 16HBE-C cells, and this could be inhibited, to different degrees, by tyrosine kinase inhibitors. Inhibiting tyrosine phosphorylation in 16HBE-C cells by three selected tyrosine protein kinase inhibitors, tyrphostin 47, AG112 and AG555, caused G 0 /G 1 -phase cell cycle arrest. Our results suggest that anti-BPDE can cause the over-expression of TPX2 and its aberrant tyrosine phosphorylation. Misregulation of TPX2 affects the cell cycle state, proliferation rates and apoptosis

  3. Sterol synthesis. A novel reductive rearrangement of an alpha,beta-unsaturated steroidal epoxide; a new chemical synthesis of 5alpha-cholest-8(14)-en-3beta, 15alpha-diol.

    Science.gov (United States)

    Parish, E J; Schroepfer, G J

    1977-04-01

    Reduction of 3beta-benzoyloxy-14alpha,15alpha-epoxy-5alpha-cholest-7-ene with either lithium triethylboro-hydride or lithium aluminum hydride (4 molar excess) gave 5-alpha-cholest-8(14)-en-3beta,15alpha-diol in high yield. Reduction of the epoxy ester with lithium triethylborodeuteride or lithium aluminum deuteride (4 molar excess) gave [7alpha-2-H]-5alpha-cholest-8(14)-en-3beta,15alpha-diol. Reduction of 2beta-benzoyloxy-14alpha,15alpha-epoxy-5alpha-cholest-7-ene with a large excess (24 molar excess) of lithium aluminum hydride gave, in addition to the expected 5alpha-cholest-8(14)-en-3beta,15alpha-diol, a significant yield (33%) of 5alpha-cholest-8(14)-en-3beta-o1. Reduction of the epoxy ester with a large excess (24 molar excess) of lithium aluminum deuteride gave [7alpha-2H]-5alpha-cholest-8(14)-en-3beta,15alpha-diol and 5alpha-cholest-8(14)-en-3beta-o1 which contained two atoms of stably bound deuterium.

  4. Overexpression of Catalase Enhances Benzo(a)pyrene Detoxification in Endothelial Microsomes.

    Science.gov (United States)

    Yang, Fang; Yang, Hong; Ramesh, Aramandla; Goodwin, J Shawn; Okoro, Emmanuel U; Guo, ZhongMao

    2016-01-01

    We previously reported that overexpression of catalase upregulated xenobiotic- metabolizing enzyme (XME) expression and diminished benzo(a)pyrene (BaP) intermediate accumulation in mouse aortic endothelial cells (MAECs). Endoplasmic reticulum (ER) is the most active organelle involved in BaP metabolism. To examine the involvement of ER in catalase-induced BaP detoxification, we compared the level and distribution of XMEs, and the profile of BaP intermediates in the microsomes of wild-type and catalase transgenic endothelial cells. Our data showed that endothelial microsomes were enriched in cytochrome P450 (CYP) 1A1, CYP1B1 and epoxide hydrolase 1 (EH1), and contained considerable levels of quinone oxidoreductase-1 (NQO1) and glutathione S-transferase-pi (GSTP). Treatment of wild-type MAECs with 1μM BaP for 2 h increased the expression of microsomal CYP1A1, 1B1 and NQO1 by ~300, 64 and 116%, respectively. However, the same treatment did not significantly alter the expression of EH1 and GSTP. Overexpression of catalase did not significantly increase EH1, but upregulated BaP-induced expression of microsomal CYP1A1, 1B1, NQO1 and GSTP in the following order: 1A1>NQO1>GSTP>1B1. Overexpression of catalase did not alter the distribution of each of these enzymes in the microsomes. In contrast to our previous report showing lower level of BaP phenols versus BaP diols/diones in the whole-cell, this report demonstrated that the sum of microsomal BaP phenolic metabolites were ~60% greater than that of the BaP diols/diones after exposure of microsomes to BaP. Overexpression of catalase reduced the concentrations of microsomal BaP phenols and diols/diones by ~45 and 95%, respectively. This process enhanced the ratio of BaP phenol versus diol/dione metabolites in a potent manner. Taken together, upregulation of phase II XMEs and CYP1 proteins, but not EH1 in the ER might be the mechanism by which overexpression of catalase reduces the levels of all the BaP metabolites, and

  5. p53 Mutagenesis by Benzo[a]pyrene derived Radical Cations

    Science.gov (United States)

    Sen, Sushmita; Bhojnagarwala, Pratik; Francey, Lauren; Lu, Ding; Jeffrey Field, Trevor M. Penning

    2013-01-01

    Benzo[a]pyrene (B[a]P), a major human carcinogen in combustion products such as cigarette smoke and diesel exhaust, is metabolically activated into DNA-reactive metabolites via three different enzymatic pathways. The pathways are the anti-(+)-benzo[a]pyrene 7,8-diol 9, 10-epoxide pathway (P450/ epoxide hydrolase catalyzed) (B[a]PDE), the benzo[a]pyrene o-quinone pathway (aldo ketose reductase (AKR) catalyzed) and the B[a]P radical cation pathway (P450 peroxidase catalyzed). We used a yeast p53 mutagenesis system to assess mutagenesis by B[a]P radical cations. Because radical cations are short-lived, they were generated in situ by reacting B[a]P with cumene hydroperoxide (CuOOH) and horse radish peroxidase (HRP) and then monitoring the generation of the more stable downstream products, B[a]P-1,6-dione and B[a]P-3,6-dione. Based on the B[a]P-1,6 and 3,6-dione formation, approximately 4µM of radical cation was generated. In the mutagenesis assays, the radical cations produced in situ showed a dose-dependent increase in mutagenicity from 0.25 µM to 10 µM B[a]P with no significant increase seen with further escalation to 50 µM B[a]P. However, mutagenesis was 200-fold less than with the AKR pathway derived B[a]P, 7–8 dione. Mutant p53 plasmids, which yield red colonies, were recovered from the yeast to study the pattern and spectrum of mutations. The mutation pattern observed was G to T (31%) > G to C (29%) > G to A (14%). The frequency of codons mutated by the B[a]P radical cations was essentially random and not enriched at known cancer hotspots. The quinone products of radical cations, B[a]P-1,6-dione and B[a]P-3,6-dione were more mutagenic than the radical cation reactions, but still less mutagenic than AKR derived B[a]P-7,8-dione. We conclude that B[a]P radical cations and their quinone products are weakly mutagenic in this yeast-based system compared to redox cycling PAH o-quinones. PMID:22768918

  6. LC/MSMS STUDY OF BENZO[A]PYRENE-7,8-QUINONE ADDUCTION TO GLOBIN TRYPTIC PEPTIDES AND N-ACETYLAMINO ACIDS

    Science.gov (United States)

    Benzo[a]pyrene-7,8-quinone (BPQ) is regarded as a reactive genotoxic compound enzymatically formed from a xenobiotic precursor benzo[a]pyrene-7,8-diol by aldo-keto-reductase family of enzymes. Because BPQ, a Michael electrophile, was previously shown to react with oligonucleotide...

  7. The rabbit liver microsomal biotransformation of 1,1-dialkylethylenes: enantioface selection of epoxidation and enantioselectivity of epoxide hydrolysis.

    Science.gov (United States)

    Bellucci, G; Chiappe, C; Cordoni, A; Marioni, F

    1994-01-01

    The rabbit liver microsomal biotransformation of alpha-methylstyrene (1a), 2-methyl-1-hexene (1b), 2,4,4-trimethyl-1-pentene (1c), and 1,3,3-trimethyl-1-butene (1d) has been investigated with the aim at establishing the enantioface selection of the cytochrome P-450-promoted epoxidation of the double bond and the enantioselectivity of microsomal epoxide hydrolase(mEH)-catalyzed hydrolysis of the resulting epoxides. GLC on a Chiraldex G-TA (ASTEC) column was used to determine the enantiomeric composition of the products. The epoxides 2 first produced in incubations carried out in the presence of an NADPH regenerating system were not detected, being rapidly hydrolyzed by mEH to diols 3. The enantiomeric composition of the latter showed that no enantioface selection occurred in the epoxidation of 1c and 1d, and a very low (8%) ee of the (R)-epoxide was formed from 1b. Incubation of racemic epoxides 2b-d with the microsomal fraction showed that the mEH-catalyzed hydrolysis of 2c and 2d was practically nonenantioselective, while that of 2b exhibited a selectivity E = 4.9 favoring the hydrolysis of the (S)-enantiomer. A comparison of these results with those previously obtained for linear and branched chain alkyl monosubstituted oxiranes shows that the introduction of the second alkyl substituent suppresses the selectivity of the mEH reaction of the latter and reverses that of the former substrates.

  8. Nitrite-mediated hydrolysis of epoxides catalyzed by halohydrin dehalogenase from Agrobacterium radiobacter AD1 : A new tool for the kinetic resolution of epoxides

    NARCIS (Netherlands)

    Hasnaoui, Ghania; Lutje Spelberg, Jeffrey H.; de Vries, Erik; Tang, Lixia; Hauer, Bernhard; Janssen, Dick B.

    2005-01-01

    Halohydrin dehalogenase obtained from Agrobacterium radiobacter AD1, has been tested for the nitrite-mediated ring opening of epoxides. This reaction mainly leads to the formation of unstable hydroxynitrite ester intermediates, which can be further hydrolyzed to the corresponding diols. This

  9. Generation and characterization of epoxide hydrolase 3 (EPHX3-deficient mice.

    Directory of Open Access Journals (Sweden)

    Samantha L Hoopes

    Full Text Available Cytochrome P450 (CYP epoxygenases metabolize arachidonic acid into epoxyeicosatrienoic acids (EETs, which play an important role in blood pressure regulation, protection against ischemia-reperfusion injury, angiogenesis, and inflammation. Epoxide hydrolases metabolize EETs to their corresponding diols (dihydroxyeicosatrienoic acids; DHETs which are biologically less active. Microsomal epoxide hydrolase (EPHX1, mEH and soluble epoxide hydrolase (EPHX2, sEH were identified >30 years ago and are capable of hydrolyzing EETs to DHETs. A novel epoxide hydrolase, EPHX3, was recently identified by sequence homology and also exhibits epoxide hydrolase activity in vitro with a substrate preference for 9,10-epoxyoctadecamonoenoic acid (EpOME and 11,12-EET. EPHX3 is highly expressed in the skin, lung, stomach, esophagus, and tongue; however, its endogenous function is unknown. Therefore, we investigated the impact of genetic disruption of Ephx3 on fatty acid epoxide hydrolysis and EET-related physiology in mice. Ephx3-/- mice were generated by excising the promoter and first four exons of the Ephx3 gene using Cre-LoxP methodology. LC-MS/MS analysis of Ephx3-/- heart, lung, and skin lysates revealed no differences in endogenous epoxide:diol ratios compared to wild type (WT. Ephx3-/- mice also exhibited no change in plasma levels of fatty acid epoxides and diols relative to WT. Incubations of cytosolic and microsomal fractions prepared from Ephx3-/- and WT stomach, lung, and skin with synthetic 8,9-EET, 11,12-EET, and 9,10-EpOME revealed no significant differences in rates of fatty acid diol formation between the genotypes. Ephx3-/- hearts had similar functional recovery compared to WT hearts following ischemia/reperfusion injury. Following intranasal lipopolysaccharide (LPS exposure, Ephx3-/- mice were not different from WT in terms of lung histology, bronchoalveolar lavage fluid cell counts, or fatty acid epoxide and diol levels. We conclude that genetic

  10. One step synthesis of 6-oxo-cholestan-3β,5α-diol

    International Nuclear Information System (INIS)

    Voisin, Maud; Silvente-Poirot, Sandrine; Poirot, Marc

    2014-01-01

    Highlights: • Cholesterol-5,6-epoxides are metabolized into cholestane-3β,5α,6β-triol (CT) in cancer cells. • 6-Oxo-cholestan-3β,5α-diol (OCDO) is a putative metabolite of CT. • The one step syntheses of CT and OCDO from cholesterol are reported. • The one step syntheses of labelled CT and OCDO are reported. - Abstract: Cholesterol metabolism has been recently linked to cancer, highlighting the importance of the characterization of new metabolic pathways in the sterol series. One of these pathways is centered on cholesterol-5,6-epoxides (5,6-ECs). 5,6-ECs can either generate dendrogenin A, a tumor suppressor present in healthy mammalian tissues, or the carcinogenic cholestane-3β,5α,6β-triol (CT) and its putative metabolite 6-oxo-cholestan-3β,5α-diol (OCDO) in tumor cells. We are currently investigating the identification of the enzyme involved in OCDO biosynthesis, which would be highly facilitated by the use of commercially unavailable [ 14 C]-cholestane-3β,5α,6β-triol and [ 14 C]-6-oxo-cholestan-3β,5α-diol. In the present study we report the one-step synthesis of [ 14 C]-cholestane-3β,5α,6β-triol and [ 14 C]-6-oxo-cholestan-3β,5α-diol by oxidation of [ 14 C]-cholesterol with iodide metaperiodate (HIO 4 )

  11. Influence of cell cycle on responses of MCF-7 cells to benzo[a]pyrene

    Directory of Open Access Journals (Sweden)

    Giddings Ian

    2011-06-01

    Full Text Available Abstract Background Benzo[a]pyrene (BaP is a widespread environmental genotoxic carcinogen that damages DNA by forming adducts. This damage along with activation of the aryl hydrocarbon receptor (AHR induces complex transcriptional responses in cells. To investigate whether human cells are more susceptible to BaP in a particular phase of the cell cycle, synchronised breast carcinoma MCF-7 cells were exposed to BaP. Cell cycle progression was analysed by flow cytometry, DNA adduct formation was assessed by 32P-postlabeling analysis, microarrays of 44K human genome-wide oligos and RT-PCR were used to detect gene expression (mRNA changes and Western blotting was performed to determine the expression of some proteins, including cytochrome P450 (CYP 1A1 and CYP1B1, which are involved in BaP metabolism. Results Following BaP exposure, cells evaded G1 arrest and accumulated in S-phase. Higher levels of DNA damage occurred in S- and G2/M- compared with G0/G1-enriched cultures. Genes that were found to have altered expression included those involved in xenobiotic metabolism, apoptosis, cell cycle regulation and DNA repair. Gene ontology and pathway analysis showed the involvement of various signalling pathways in response to BaP exposure, such as the Catenin/Wnt pathway in G1, the ERK pathway in G1 and S, the Nrf2 pathway in S and G2/M and the Akt pathway in G2/M. An important finding was that higher levels of DNA damage in S- and G2/M-enriched cultures correlated with higher levels of CYP1A1 and CYP1B1 mRNA and proteins. Moreover, exposure of synchronised MCF-7 cells to BaP-7,8-diol-9,10-epoxide (BPDE, the ultimate carcinogenic metabolite of BaP, did not result in significant changes in DNA adduct levels at different phases of the cell cycle. Conclusions This study characterised the complex gene response to BaP in MCF-7 cells and revealed a strong correlation between the varying efficiency of BaP metabolism and DNA damage in different phases of the cell

  12. Epoxidation catalyst and process

    Science.gov (United States)

    Linic, Suljo; Christopher, Phillip

    2010-10-26

    Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

  13. Catalytic Epoxidation of Limonene

    Directory of Open Access Journals (Sweden)

    E. Herrero

    2000-03-01

    Full Text Available The epoxidation of limonene with hidrogen peroxide was studied over zeolite Tibeta (a large pore material and heteropoly acids on carbono and alumina supported. PW11/C was catalyst the best tested.

  14. Stereo-selectivity and regio-selectivity in the metabolism of 7,8-dihydrobenzo[a]pyrene by cytochrome P450, epoxide hydrolase and hepatic microsomes from 3-methylcholanthrene-treated rats.

    Science.gov (United States)

    Adams, J D; Yagi, H; Levin, W; Jerina, D M

    1995-03-30

    The active site of cytochrome P450 1A1 has been probed with the substrate 7,8-dihydrobenzo[a]pyrene using a purified, reconstituted system composed of cytochrome P450 1A1, NADPH-cytochrome c reductase and lipid in the presence or absence of epoxide hydrolase. The turnover of the substrate was found to be 38 nmol/nmol of cytochrome P450/min. The metabolic products that were identified are: a phenolic 7,8-dihydrobenzo[a]pyrene (20-29%); 9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (17-28%); benzo[a]pyrene (12-19%); 7-hydroxy-7,8-dihydrobenzo[a]pyrene (13-16%); 8-hydroxy-7,8-dihydrobenzo[a]pyrene (7-15%); 3-hydroxybenzo[a]pyrene (7-15%); 4,5-epoxy-4,5,7,8-tetrahydrobenzo[a]pyrene (0-4%); and a triol of 7,8,9,10-tetrahydrobenzo[a]pyrene (0-4%). 9,10-Epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene undergoes rapid hydrolysis to cis- and trans-9,10-dihydroxy-dihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene (2:1) by benzylic attack of water at C-10. Approximately 71% of the trans diols are derived from (+)-(9S,10R)-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene, indicating that cytochrome P450 1A1 has more than a 2:1 preference for selective epoxidation of an enantiotopic face of 7,8-dihydrobenzo[a]pyrene. This stereo-selectivity agrees with the postulated stereo-selectivity predicted by a previously described active site model for cytochrome P450 1A1. Epoxide hydrolase in pure form or in hepatic microsomes catalyzes the hydrolysis of 9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene, which is inhibited by 1,1,1-trichloropropane 2,3-oxide. The (+)-(9S,10R)-isomer of the epoxide is slightly preferred as a substrate over its enantiomer and is cleaved by benzylic and nonbenzylic attack. Only benzylic attack was found with (-)-(9R,10S)-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene.

  15. CHARACTERIZATION OF STABLE BENZO(A)PYRENE-7,8-QUINONE-DNA ADDUCTS IN CALF THYMUS DNA

    Science.gov (United States)

    Benzo[alpyrene-7,8-dione (BPQ) is a reactive aldo-keto reductase-mediated product of B[a]P-7,8-diol, a major P450/epoxide hydrolase metabolite of the multi-species carcinogen, B[a]P. The role of BPQ in B[a]P's genotoxicity and carcinogenesis is evolving. Toxicity pathways involvi...

  16. Purification and partial characterization of peroxidase from human term placenta of non-smokers: metabolism of benzo(a)pyrene-7, 8-dihydrodiol.

    Science.gov (United States)

    Madhavan, N D; Naidu, K A

    2000-01-01

    -tetrols, the hydrolytic products of BP-diol-epoxides, demonstrating the ability of peroxidase in bioactivation of benzo(a)pyrene in human placenta. Copyright 2000 Harcourt Publishers Ltd.

  17. One step synthesis of 6-oxo-cholestan-3β,5α-diol

    Energy Technology Data Exchange (ETDEWEB)

    Voisin, Maud; Silvente-Poirot, Sandrine; Poirot, Marc, E-mail: marc.poirot@inserm.fr

    2014-04-11

    Highlights: • Cholesterol-5,6-epoxides are metabolized into cholestane-3β,5α,6β-triol (CT) in cancer cells. • 6-Oxo-cholestan-3β,5α-diol (OCDO) is a putative metabolite of CT. • The one step syntheses of CT and OCDO from cholesterol are reported. • The one step syntheses of labelled CT and OCDO are reported. - Abstract: Cholesterol metabolism has been recently linked to cancer, highlighting the importance of the characterization of new metabolic pathways in the sterol series. One of these pathways is centered on cholesterol-5,6-epoxides (5,6-ECs). 5,6-ECs can either generate dendrogenin A, a tumor suppressor present in healthy mammalian tissues, or the carcinogenic cholestane-3β,5α,6β-triol (CT) and its putative metabolite 6-oxo-cholestan-3β,5α-diol (OCDO) in tumor cells. We are currently investigating the identification of the enzyme involved in OCDO biosynthesis, which would be highly facilitated by the use of commercially unavailable [{sup 14}C]-cholestane-3β,5α,6β-triol and [{sup 14}C]-6-oxo-cholestan-3β,5α-diol. In the present study we report the one-step synthesis of [{sup 14}C]-cholestane-3β,5α,6β-triol and [{sup 14}C]-6-oxo-cholestan-3β,5α-diol by oxidation of [{sup 14}C]-cholesterol with iodide metaperiodate (HIO{sub 4})

  18. Rapid synthesis of macrocycles from diol precursors

    DEFF Research Database (Denmark)

    Wingstrand, Magnus; Madsen, Charlotte Marie; Clausen, Mads Hartvig

    2009-01-01

    A method for the formation of synthetic macrocycles with different ring sizes from diols is presented. Reacting a simple diol precursor with electrophilic reagents leads to a cyclic carbonate, sulfite or phosphate in a single step in 25-60% yield. Converting the cyclization precursor to a bis-ele...

  19. Dysregulation of soluble epoxide hydrolase and lipidomic profiles in anorexia nervosa

    KAUST Repository

    Shih, P. B.

    2015-03-31

    Individuals with anorexia nervosa (AN) restrict eating and become emaciated. They tend to have an aversion to foods rich in fat. Because epoxide hydrolase 2 (EPHX2) was identified as a novel AN susceptibility gene, and because its protein product, soluble epoxide hydrolase (sEH), converts bioactive epoxides of polyunsaturated fatty acid (PUFA) to the corresponding diols, lipidomic and metabolomic targets of EPHX2 were assessed to evaluate the biological functions of EPHX2 and their role in AN. Epoxide substrates of sEH and associated oxylipins were measured in ill AN, recovered AN and gender- and race-matched controls. PUFA and oxylipin markers were tested as potential biomarkers for AN. Oxylipin ratios were calculated as proxy markers of in vivo sEH activity. Several free- and total PUFAs were associated with AN diagnosis and with AN recovery. AN displayed elevated n-3 PUFAs and may differ from controls in PUFA elongation and desaturation processes. Cytochrome P450 pathway oxylipins from arachidonic acid, linoleic acid, alpha-linolenic acid and docosahexaenoic acid PUFAs are associated with AN diagnosis. The diol:epoxide ratios suggest the sEH activity is higher in AN compared with controls. Multivariate analysis illustrates normalization of lipidomic profiles in recovered ANs. EPHX2 influences AN risk through in vivo interaction with dietary PUFAs. PUFA composition and concentrations as well as sEH activity may contribute to the pathogenesis and prognosis of AN. Our data support the involvement of EPHX2-associated lipidomic and oxylipin dysregulations in AN, and reveal their potential as biomarkers to assess responsiveness to future intervention or treatment.

  20. Iridium catalysed synthesis of piperazines from diols

    DEFF Research Database (Denmark)

    Nordstrøm, Lars Ulrik Rubæk; Madsen, Robert

    2007-01-01

    A green and atom-economical method has been developed for the synthesis of piperazines by cyclocondensation of diols and amines in aqueous media in the presence of a catalytic amount of [Cp*IrCl2]2....

  1. Metabolic interactions between low doses of benzo[a]pyrene and tributyltin in arctic charr (salvelinus alpinus): a long-term in vivo study

    International Nuclear Information System (INIS)

    Padros, Jaime; Pelletier, Emilien; Ribeiro, Ciro Oliveira

    2003-01-01

    We have previously reported that short-term, single exposure to a high dose of tributyltin (TBT), a widely used antifouling biocide, inhibited both the in vivo metabolism and metabolic activation of the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) in fish; (BaP), in turn, stimulated TBT metabolism. Here, we provide further mechanistic evidence of mutual metabolic interactions between BaP and TBT in response to long-term, repeated exposures to low doses. Juvenile Arctic charr (Salvelinus alpinus) received 10 separate ip injections (a single injection every 6 days) of BaP (3 mg/kg), TBT (0.3 mg/kg), or both in combination; control fish received corn oil vehicle only. Two days after the 2nd (Day 8), 6 th (Day 32), and 10th dose (Day 56), blood, bile, and liver samples were collected and analyzed for a suite of biomarkers. HPLC/fluorescence analysis indicated that TBT cotreatment inhibited the formation of (+)-anti-BaP diol-epoxide adducts with plasma albumin (53%, Day 8), hepatic DNA (27%, Day 32), or both albumin and globin (50 and 58%, Day 56) compared to BaP alone. This antagonistic interaction was associated with a time-dependent modulation (inhibition at Day 8, enhancement at Day 32) of both cytochrome P450 (P450)1A-mediated ethoxyresorufin O-deethylase (EROD) activity and biliary BaP metabolite formation. TBT cotreatment also inhibited (39%) the BaP-mediated induction of hepatic glutathione S-transferase (GST) activity observed at Day 8. Treatment with TBT alone increased EROD activity (60%) at Day 32, but decreased both GST activity (70 and 37%) and glutathione content (24% and 16%) at Days 32 and 56, respectively. GC/MS analysis revealed that, at Day 56, BaP cotreatment increased (200%) the levels of biliary butyltin compounds, including mono- and dibutyltin metabolites. This potentiative interaction was associated with a protective effect of BaP cotreatment against the TBT-mediated decreases in GST activity and glutathione content. The

  2. Evaluation of the precision-cut liver and lung slice systems for the study of induction of CYP1, epoxide hydrolase and glutathione S-transferase activities.

    Science.gov (United States)

    Pushparajah, Daphnee S; Umachandran, Meera; Plant, Kathryn E; Plant, Nick; Ioannides, Costas

    2007-02-28

    The principal objective was to ascertain whether precision-cut tissue slices can be used to evaluate the potential of chemicals to induce CYP1, epoxide hydrolase and glutathione S-transferase activities, all being important enzymes involved in the metabolism of polycyclic aromatic hydrocarbons. Precision-cut rat liver and lung slices were incubated with a range of benzo[a]pyrene concentrations for various time periods. A rise in the O-deethylation of ethoxyresorufin was seen in both liver and lung slices exposed to benzo[a]pyrene, which was accompanied by increased CYP1A apoprotein levels. Pulmonary CYP1B1 apoprotein levels and hepatic mRNA levels were similarly enhanced. Elevated epoxide hydrolase and glutathione S-transferase activities were also observed in liver slices following incubation for 24h; similarly, a rise in apoprotein levels of both enzymes was evident, peak levels occurring at the same time point. When mRNA levels were monitored, a rise in the levels of both enzymes was seen as early as 4h after incubation, but maximum levels were attained at 24 h. In lung slices, induction of epoxide hydrolase by benzo[a]pyrene was observed after a 24-h incubation, and at a concentration of 1 microM; a rise in apoprotein levels was seen at this time point. Glutathione S-transferase activity was not inducible in lung slices by benzo[a]pyrene but a modest increase was observed in hepatic slices. Collectively, these studies confirmed CYP1A induction in rat liver slices and established that CYP1B1 expression, and epoxide hydrolase and glutathione S-transferase activities are inducible in precision-cut tissue slices.

  3. Chromium Salen Mediated Alkene Epoxidation

    DEFF Research Database (Denmark)

    Petersen, Kaare Brandt; Norrby, Per-Ola; Daly, Adrian M.

    2002-01-01

    The mechanism of alkene epoxidation by chromium(v) oxo salen complexes has been studied by DFT and experimental methods. The reaction is compared to the closely related Mn-catalyzed process in an attempt to understand the dramatic difference in selectivity between the two systems. Overall......-spin surface. The low-spin addition of metal oxo species to an alkene leads to an intermediate which forms epoxide either with a barrier on the low-spin surface or without a barrier after spin inversion. Supporting evidence for this intermediate was obtained by using vinylcyclopropane traps. The chromium...

  4. Kinetics and mechanism of the oxidation of some diols by ...

    Indian Academy of Sciences (India)

    Abstract. The kinetics of oxidation of five vicinal and four non-vicinal diols, and two of their monoethers by benzyltrimethylammonium tribromide (BTMAB) have been studied in 3:7 (v/v) acetic acid–water mixture. The vicinal diols yield the carbonyl compounds arising out of the glycol bond fission while the other diols give.

  5. Multiphoton spectral analysis of benzo[a]pyrene uptake and metabolism in a rat liver cell line

    International Nuclear Information System (INIS)

    Barhoumi, Rola; Mouneimne, Youssef; Ramos, Ernesto; Morisseau, Christophe; Hammock, Bruce D.; Safe, Stephen; Parrish, Alan R.; Burghardt, Robert C.

    2011-01-01

    Dynamic analysis of the uptake and metabolism of polycyclic aromatic hydrocarbons (PAHs) and their metabolites within live cells in real time has the potential to provide novel insights into genotoxic and non-genotoxic mechanisms of cellular injury caused by PAHs. The present work, combining the use of metabolite spectra generated from metabolite standards using multiphoton spectral analysis and an 'advanced unmixing process', identifies and quantifies the uptake, partitioning, and metabolite formation of one of the most important PAHs (benzo[a]pyrene, BaP) in viable cultured rat liver cells over a period of 24 h. The application of the advanced unmixing process resulted in the simultaneous identification of 8 metabolites in live cells at any single time. The accuracy of this unmixing process was verified using specific microsomal epoxide hydrolase inhibitors, glucuronidation and sulfation inhibitors as well as several mixtures of metabolite standards. Our findings prove that the two-photon microscopy imaging surpasses the conventional fluorescence imaging techniques and the unmixing process is a mathematical technique that seems applicable to the analysis of BaP metabolites in living cells especially for analysis of changes of the ultimate carcinogen benzo[a]pyrene-r-7,t-8-dihydrodiol-t-9,10-epoxide. Therefore, the combination of the two-photon acquisition with the unmixing process should provide important insights into the cellular and molecular mechanisms by which BaP and other PAHs alter cellular homeostasis.

  6. Metabolism of polyunsaturated (n-3) fatty acids by monkey seminal vesicles: isolation and biosynthesis of omega-3 epoxides.

    Science.gov (United States)

    Oliw, E H; Sprecher, H W

    1991-11-27

    Monooxygenases of monkey seminal vesicles can metabolize arachidonic acid (20:4(n-6)) by w3-hydroxylation to 18(R)-hydroxyeicosatetraenoic acid (18(R)-HETE) and eicosapentaenoic acid (20:5(n-3)) to 17,18-dihydroxyeicosatetraenoic acid (Oliw, E.H. (1989) J. Biol. Chem. 264, 17845-17853). The present study aimed to further characterize the oxygenation of (n-3) polyunsaturated fatty acids. 14C-Labelled 22:6(n-3), 20:5(n-3), 20:4-(n-3) and 18:3(n-3) were incubated with microsomes of seminal vesicles of the cynomolgus monkey, NADPH and a cyclooxygenase inhibitor, diclofenac, and the main metabolites were identified by capillary gas chromatography-mass spectrometry. 22:6(n-3) was slowly metabolized to 19,20-dihydroxy-4,7,10,13,16-docosapentaenoic acid, while 20:5(n-3), 20:4(n-3) and 18:3(n-3) were metabolized more efficiently to the corresponding w4,w3-diols. The w3 epoxides, which were obtained from 20:5(n-3) and 18:3(n-3), were isolated in the presence of an epoxide hydrolase inhibitor, 1(2)epoxy-3,3,3-trichloropropane, and the geometry of the epoxides was determined to be 17S, 18R and 15S, 16R, respectively. While 20:5(n-3) was metabolized almost exclusively to the epoxide and diol pair of metabolites, 18:3(n-3) was metabolized not only to the w3 epoxide and the corresponding diol, but also to the w2 alcohol, 17(R)-hydroxy-9,12,15-octadecatrienoic acid. 22:6(n-3) and 5,8,11,14-eicosatetraynoic acid inhibited the biosynthesis of 18(R)-HETE from arachidonic acid (IC50 0.16 and 0.14 mM, respectively). In comparison with 20:4 or 18:3(n-3), 18:1(n-9) and 22:5(n-6) appeared to be slowly metabolized by seminal monooxygenases, while 18:2(n-6) was converted to the w3 alcohol and to smaller amounts of the w2 alcohol (4:1). Together, the results indicate that the w3-hydroxylase and w3-epoxygenase enzyme(s) metabolize 20:4(n-6) and 20:5(n-3) almost exclusively to the w3(R) alcohol and the w3(R, S) epoxide, respectively, while longer and shorter fatty acids either are poor

  7. Solar Synthesis of Limonene Epoxide

    OpenAIRE

    Ciriminna, Rosaria; Parrino, Francesco; Pasquale, Claudio De; Palmisano, Leonardo; Pagliaro, Mario

    2017-01-01

    The silylation of crystalline titania P25, commonly used for photocatalytic degradation of pollutants, results in an exceptionally selective catalyst for the aerobic limonene epoxidation to 1,2-limonene oxide under solar light irradiation. The hypothesized mechanism involves the singlet oxygen generated through energy transfer from the excited TiO2 to adsorbed O2 molecules. The reaction product is the valued precursor of bio-based poly(limonene carbonate), a thermoplastic po...

  8. Effect of dietary factors on mutagenesis, metabolism, and binding to DNA of benzo[a]pyrene and benzo[a]pyrene 7,8-dihydrodiol

    International Nuclear Information System (INIS)

    Vance, R.E.

    1988-01-01

    Ellagic acid (EA), a naturally occurring plant phenol, at concentrations of 5 to 50 μg/plate, inhibited rate liver S9 protein dependent benzo[a]pyrene (B[a]P)-induced mutagenesis in Salmonella typhimurium TA 100 by 30-81% and B[a]P 7,8-dihydrodiol (DHD)-induced mutagenesis by 29 to 75%. EA did not significantly affect the metabolism of B[a]P or B[a]P 7,8-DHD as determined by high performance liquid chromatographic analysis of the organosoluble fraction and by the quantification of water-soluble conjugates. At these concentrations EA inhibited the covalent binding of [ 3 H] B[a]P and [ 3 H] B[a]P 7,8-DHD metabolites to calf thymus DNA by 5 to 42% and 27 to 64%, respectively. Formation of benzo[a]pyrene 7,8-dihydrodiol-9,10-epoxide:deoxyguanosine (BPDE:dG) adducts was inhibited by 13 to 56% for B[a]P for B[a]P and 11 to 38% for B[a]P 7,8-DHD. These results suggest that the antimutagenic effect of EA and its inhibition of B[a]P and B[a]P 7,8-DHD metabolite-binding to DNA is not due to the inhibition of S9-mediated metabolism of these compounds. The inhibitory effect may be by previously described scavenging mechanism or by a DNA-affinity binding mechanism that prevents BPDE:DNA adduct formation

  9. New applications of the interaction between diols and boronic acids

    NARCIS (Netherlands)

    Duval, F.L.

    2015-01-01

    Florine Duval - New applications of the interaction between diols and boronic acids – Summary

    Chapter 1 introduces the theory and known applications of the interaction between boronic acids and diols, and explains the context of this thesis. Diagnosis of

  10. Synthesis and complexation characteristics of phenanthroline and bipyridine diols

    NARCIS (Netherlands)

    Koning, B.; Boer, J.W. de; Meetsma, A.; Kellogg, R.M.

    2004-01-01

    Neocuproine (2,9-dimethyl-1,10-phenanthroline) 1 was converted to achiral and chiral tetradentate phenanthroline diols 3a-c by addition to benzophenone, adamantanone and camphor, respectively. Analogously 6,6'-dimethyl-2,2'-bipyridine 2 was converted to diol 7a on base-induced addition to

  11. Epoxidation of linseed oil-Alkyd resins

    International Nuclear Information System (INIS)

    Motawie, A.M.; Ismail, E.A.; Mazroua, A.M.; Abd EI Aziem, M.S.; Ramadan, A.M.

    2004-01-01

    Three types of different linseed oil-alkyd resin ( Alk (I), Alk (II), and Alk (III) ) were prepared with the calculated amounts of mono glycerides and adipic acid (1:1, 1:2, and 2:1 Eq.Wt) respectively via monoglyceride method. The obtained alkyd resins were epoxidized via reaction with the calculated quantities of peracetic acid, which was prepared by the reaction of acetic anhydride with H 2 O 2 . Epoxidation occurred with the ratio (1: 1, 1 :3, and 1:6 Eq. Wt) of alkyd to peracetic acid. The effect of reaction time on the epoxy group content was measured during the epoxidation process. The prepared alkyd resins were analyzed by IR and H 1 NMR. The metal coated film properties of epoxidized alkyd resins were compared with those of unmodified alkyd resins. It was observed that the coating films of epoxidized alkyd resins have better in drying properties, hardness, adhesion, impact and flexibility than those of un epoxidized alkyd resins. The flammability properties of the paper coated films for the prepared brominated epoxidized alkyd resins were found to be fire retardant

  12. Diastereoselectivity in scalemic tartrate/titanium epoxidations.

    Science.gov (United States)

    Brown, J M; Leppard, S J; Oakes, J; Thornthwaite, D

    2000-06-01

    Nonlinearity in the diastereoselectivity of epoxidation of allylic alcohols with mixtures of titanium isopropoxide, tertbutyl hydroperoxide, and diethyl tartrate was observed. Racemic and enantiomerically pure alcohols E-2-methyl-4-hexen-3-ol and E-1-methoxy-5-(O-tertbutyldimethylsilyloxy)-2-penten-4-ol were prepared. Epoxidation reactions were carried out with Ti(OPri)4 and ButOOH accompanied by diethyl tartrate of varying enantiomeric purity. The simplest explanation of these results is that a dimeric epoxidation reagent is involved, with significantly different reactivity for the homochiral and racemic forms. Copyright 2000 Wiley-Liss, Inc.

  13. Reaction of cyclic epoxide compounds with triphenylphosphine

    International Nuclear Information System (INIS)

    Kas'yan, L.I.; Stepanova, N.V.; Galafeeva, M.F.; Boldeskul, I.E.; Trachevskii, V.V.; Zefirov, N.S.

    1987-01-01

    Significant differences were found in the reactivity of a series of epoxides of cycloalkenes and methylenecycloalkanes and diepoxides in reaction with triphenylphosphine, depending both on the steric effects of the cyclic fragments and on their strain. The level of the strain can be judged indirectly from the chemical shifts of the 1 H and 13 C nuclei and the spin-spin coupling constants of the C-H bonds in the epoxide ring

  14. Cycloaliphatic epoxide resins for cationic UV - cure

    International Nuclear Information System (INIS)

    Verschueren, K.; Balwant Kaur

    1999-01-01

    This paper introduces the cyclo - aliphatic epoxide resins used for the various applications of radiation curing and their comparison with acrylate chemistry. Radiation curable coatings and inks are pre - dominantly based on acrylate chemistry but over the last few years, cationic chemistry has emerged successfully with the unique properties inherent with cyclo - aliphatic epoxide ring structures. Wide variety of cationic resins and diluents, the formulation techniques to achieve the desired properties greatly contributes to the advancement of UV - curing technology

  15. Pharmacokinetics: time-dependent changes--autoinduction of carbamazepine epoxidation

    International Nuclear Information System (INIS)

    Bertilsson, L.; Tomson, T.; Tybring, G.

    1986-01-01

    Drugs labeled with stable isotopes have been useful to study time-dependent changes in kinetics. Early studies suggested that carbamazepine (CBZ) may induce its own metabolism, but this could not be proved until tetradeuterium-labeled CBZ (CBZ-D4) was synthesized and then given to patients. CBZ-D4 was administered to three children during long-term treatment of epilepsy with CBZ. After 17 to 32 days of treatment, the plasma clearance of CBZ-D4 was doubled, but during the next four months, there was no further increase, indicating that autoinduction was complete within one month. Two patients with chronic alcoholism were treated with CBZ for five days. Half of the first dose of 600 mg was comprised of CBZ-D4. The half-life of this CBZ-D4 dose in the two patients (20 and 26 hr, respectively) was similar to the post-steady-state half-life of CBZ (23 hr in both patients) measured later. A single dose of CBZ given one week after the last maintenance dose had a longer half-life (46 and 45 hr, respectively), which probably is close to the disposition of the drug before starting the treatment with CBZ. This shows that autoinduction of CBZ metabolism was completed during the very first doses of CBZ. Autoinduction also disappeared rapidly after stopping the treatment. We have shown that it is mainly the epoxide-diol pathway that is induced, both during autoinduction and after induction with other antiepileptic agents

  16. Deep Eutectic Solvents Enable More Robust Chemoenzymatic Epoxidation Reactions

    NARCIS (Netherlands)

    Zhou, Pengfei; Wang, Xuping; Zeng, Chaoxi; Wang, Weifei; Yang, Bo; Hollmann, F.; Wang, Yonghua

    2017-01-01

    A chemoenzymatic method for the production of epoxidized vegetable oils was developed. The unique combination of the commercial lipase G from Penicillieum camembertii with certain deep eutectic solvents enabled the efficient production of epoxidized vegetable oils.

  17. Enantioselectivity of a recombinant epoxide hydrolase from Agrobacterium radiobacter

    NARCIS (Netherlands)

    Lutje Spelberg, Jeffrey H.; Rink, Rick; Kellogg, Richard M.; Janssen, Dick B.

    1998-01-01

    The recombinant epoxide hydrolase from Agrobacterium radiobacter AD1 was used to obtain enantiomerically pure epoxides by means of a kinetic resolution. Epoxides such as styrene oxide and various derivatives thereof and phenyl glycidyl ether were obtained in high enantiomeric excess and in

  18. 21 CFR 172.723 - Epoxidized soybean oil.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Epoxidized soybean oil. 172.723 Section 172.723... CONSUMPTION Other Specific Usage Additives § 172.723 Epoxidized soybean oil. Epoxidized soybean oil may be... reacting soybean oil in toluene with hydrogen peroxide and formic acid. (b) It meets the following...

  19. Development of analytical methods for the gas chromatographic determination of 1,2-epoxy-3-butene, 1,2:3,4-diepoxybutane, 3-butene-1,2-diol, 3,4-epoxybutane-1,2-diol and crotonaldehyde from perfusate samples of 1,3-butadiene exposed isolated mouse and rat livers

    Energy Technology Data Exchange (ETDEWEB)

    Bhowmik, S.; Schuster, A.; Filser, J.G.

    2003-07-01

    Mutagenicity and carcinogenicity of 1,3-butadiene (BD) highly probably results from epoxide metabolites as 1,2-epoxy-3-butene (EB), 1,2:3,4-diepoxybutane (DEB) and 3,4-epoxybutane-1,2-diol (EBD). A further metabolite crotonaldehyde (CA) has also been discussed to be relevant. So far, in BD exposed rodents only EB and DEB concentrations had been quantified. However, the methods used were either not very sensitive or instrumentally expensive. Therefore, the goal of the present work was to establish simple analytical methods selective and sensitive enough to determine all of these compounds and a further secondary BD intermediate, 3-butene-1,2-diol (B-diol), in BD exposed rodent livers. The once-through perfused liver system was chosen for testing the applicability of the methods to be developed, since it enables BD exposures of this quantitatively most relevant metabolising organ near to the in-vivo situation. All the metabolites were extracted from the aqueous perfusion medium and analysed using a gas chromatograph equipped with a mass selective detector (GC/MS) in the PCI mode. (orig.)

  20. Zeaxanthin epoxidation - an in vitro approach.

    Science.gov (United States)

    Kuczyńska, Paulina; Latowski, Dariusz; Niczyporuk, Sylvia; Olchawa-Pajor, Monika; Jahns, Peter; Gruszecki, Wiesław I; Strzałka, Kazimierz

    2012-01-01

    Zeaxanthin epoxidase (ZE) is an enzyme operating in the violaxanthin cycle, which is involved in photoprotective mechanisms. In this work model systems to study zeaxanthin (Zx) epoxidation were developed. Two assay systems are presented in which epoxidation of Zx was observed. In these assays two mutants of Arabidopsis thaliana which have active only one of the two xanthophyll cycle enzymes were used. The npq1 mutant possesses an active ZE and is thus able to convert Zx to violaxanthin (Vx) but the violaxanthin de-epoxidase (VDE) is inactive, so that Vx cannot be converted to Zx. The other mutant, npq2, possesses an active VDE and can convert exogenous Vx to Zx under strong light conditions but reverse reaction is not possible. The first assay containing thylakoids from npq1 and npq2 mutants of A. thaliana gave positive results and high efficiency of epoxidation reaction was observed. The amount of Zx was reduced by 25%. To optimize high efficiency of epoxidation reaction additional factors facilitating both fusion of the two types of thylakoids and incorporation of Zx to their membranes were also studied. The second kind of assay contained npq1 mutant thylakoids of A. thaliana supplemented with exogenous Zx and monogalactosyldiacylglycerol (MGDG). Experiments with different proportions of Zx and MGDG showed that their optimal ratio is 1:60. In such system, due to epoxidation, the amount of Zx was reduced by 38% of its initial level. The in vitro systems of Zx epoxidation described in this paper enable analysis some properties of the ZE without necessity of its isolation.

  1. Polymerization of epoxidized triglycerides with fluorosulfonic acid

    Science.gov (United States)

    The use of triglycerides as agri-based renewable raw materials for the development of new products is highly desirable in view of uncertain future petroleum prices. A new method of polymerizing epoxidized soybean oil has been devised with the use of fluorosulfonic acid. Depending on the reaction con...

  2. Determination of the kinetics of ethene epoxidation

    NARCIS (Netherlands)

    Schouten, E.P.S.; Schouten, E.P.S.; Borman, P.C.; Borman, P.C.; Westerterp, K.R.

    1996-01-01

    Several problems and pitfalls in the use of laboratory reactors for the determination of the kinetics of ethene epoxidation over industrial silver on α-alumina catalyst are discussed. Also, commonly used methodologies for kinetic studies are dealt with because of the general nature of some problems.

  3. Efficient epoxidation of propene using molecular catalysts

    DEFF Research Database (Denmark)

    Markovits, Iulius I. E.; Anthofer, Michael H.; Kolding, Helene

    2014-01-01

    The epoxidation of propene is performed in homogeneous phase using various molecular catalysts and H2O2 or tert-butyl hydroperoxide as oxidants. A comparison between some molybdenum catalysts and methyltrioxorhenium (MTO) shows that the well known Re catalyst is the best among the examined...

  4. Titanium impregnated borosilicate zeolites for epoxidation catalysis

    Czech Academy of Sciences Publication Activity Database

    Přech, Jan; Vitvarová, Dana; Lupínková, Lenka; Kubů, Martin; Čejka, Jiří

    2015-01-01

    Roč. 212, AUG 2015 (2015), s. 28-34 ISSN 1387-1811 R&D Projects: GA ČR GAP106/11/0819 Institutional support: RVO:61388955 Keywords : borosilicate * titanium impregnation * epoxidation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.349, year: 2015

  5. Teaching Green Chemistry with Epoxidized Soybean Oil

    Science.gov (United States)

    Barcena, Homar; Tuachi, Abraham; Zhang, Yuanzhuo

    2017-01-01

    The synthesis of epoxidized soybean oil (ESO) provides students a vantage point on the application of green chemistry principles in a series of experiments. Qualitative tests review the reactions of alkenes, whereas spectroscopic analyses provide insight in monitoring functional group transformations.

  6. Kinetic and Mechanistic Study of the pH-Dependent Activation (Epoxidation) of Prodrug Treosulfan Including the Reaction Inhibition in a Borate Buffer.

    Science.gov (United States)

    Romański, Michał; Ratajczak, Whitney; Główka, Franciszek

    2017-07-01

    A prodrug treosulfan (T) undergoes a pH-dependent activation to epoxide derivatives. The process seems to involve an intramolecular Williamson reaction (IWR) but clear kinetic evidence is lacking. Moreover, a cis-diol system present in the T structure is expected to promote complexation with boric acid. As a result, the prodrug epoxidation would be inhibited; however, this phenomenon has not been investigated. In this article, the effect of pH on the kinetics of T conversion to its monoepoxide was studied from a mechanistic point of view. Also, the influence of boric acid on the reaction kinetics was examined. The rate constants observed for the activation of T (k obs ) in acetate, phosphate, and carbonate buffers satisfied the equation logk obs  = -7.48 + 0.96 pH. The reaction was inhibited in the excess of boric acid over T, and the k obs decreased with increasing borate buffer concentration. The experimental results were consistent with the inhibition model that included the formation of a tetrahedral, anionic T-boric acid monoester. To conclude, in nonborate buffers, the T activation to (2S,3S)-1,2-epoxybutane-3,4-diol 4-methanesulfonate follows IWR mechanism. A borate buffer changes the reaction kinetics and complicates kinetic analysis. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  7. Preliminary physiologically based pharmacokinetic models for benzo[a]pyrene and dibenzo[def,p]chrysene in rodents

    International Nuclear Information System (INIS)

    Crowell, Susan Ritger; Amin, Shantu G.; Anderson, Kim A.; Krishnegowda, Gowdahalli; Sharma, Arun K.; Soelberg, Jolen J.; Williams, David E.; Corley, Richard A.

    2011-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants generated as byproducts of natural and anthropogenic combustion processes. Despite significant public health concern, physiologically based pharmacokinetic (PBPK) modeling efforts for PAHs have so far been limited to naphthalene, plus simpler PK models for pyrene, nitropyrene, and benzo[a]pyrene (B[a]P). The dearth of published models is due in part to the high lipophilicity, low volatility, and myriad metabolic pathways for PAHs, all of which present analytical and experimental challenges. Our research efforts have focused upon experimental approaches and initial development of PBPK models for the prototypic PAH, B[a]P, and the more potent, albeit less studied transplacental carcinogen, dibenzo[def,p]chrysene (DBC). For both compounds, model compartments included arterial and venous blood, flow limited lung, liver, richly perfused and poorly perfused tissues, diffusion limited fat, and a two compartment theoretical gut (for oral exposures). Hepatic and pulmonary metabolism was described for both compounds, as were fractional binding in blood and fecal clearance. Partition coefficients for parent PAH along with their diol and tetraol metabolites were estimated using published algorithms and verified experimentally for the hydroxylated metabolites. The preliminary PBPK models were able to describe many, but not all, of the available data sets, comprising multiple routes of exposure (oral, intravenous) and nominal doses spanning several orders of magnitude. Supported by Award Number P42 ES016465 from the National Institute of Environmental Health Sciences. -- Highlights: ► We present PBPK models for benzo[a]pyrene (B[a]P) and dibenzo[def,p]chrysene (DBC). ► B[a]P model accurately predicts data from multiple sources over a wide dose range. ► DBC model was based on the B[a]P model as less chemical specific data is available. ► DBC model accurately predicted preliminary

  8. Development and Uses of Offline and Web-Searchable Metabolism Databases - The Case of Benzo[a]pyrene.

    Science.gov (United States)

    Rendic, Slobodan P; Guengerich, Frederick P

    2018-01-01

    The present work describes development of offline and web-searchable metabolism databases for drugs, other chemicals, and physiological compounds using human and model species, prompted by the large amount of data published after year 1990. The intent was to provide a rapid and accurate approach to published data to be applied both in science and to assist therapy. Searches for the data were done using the Pub Med database, accessing the Medline database of references and abstracts. In addition, data presented at scientific conferences (e.g., ISSX conferences) are included covering the publishing period beginning with the year 1976. Application of the data is illustrated by the properties of benzo[a]pyrene (B[a]P) and its metabolites. Analysis show higher activity of P450 1A1 for activation of the (-)- isomer of trans-B[a]P-7,8-diol, while P4501B1 exerts higher activity for the (+)- isomer. P450 1A2 showed equally low activity in the metabolic activation of both isomers. The information collected in the databases is applicable in prediction of metabolic drug-drug and/or drug-chemical interactions in clinical and environmental studies. The data on the metabolism of searched compound (exemplified by benzo[a]pyrene and its metabolites) also indicate toxicological properties of the products of specific reactions. The offline and web-searchable databases had wide range of applications (e.g. computer assisted drug design and development, optimization of clinical therapy, toxicological applications) and adjustment in everyday life styles. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. IRIS Toxicological Review of Benzo[a]pyrene (Interagency ...

    Science.gov (United States)

    In January 2017, EPA finalized the IRIS assessment of Benzo[a]pyrene. The Toxicological Review was reviewed internally by EPA and by other federal agencies and White House Offices before public release. Consistent with the May 2009 IRIS assessment development process, all written comments on IRIS assessments submitted by other federal agencies and White House Offices are made publicly available. Accordingly, interagency comments and the interagency science discussion materials provided to other agencies, including interagency review drafts of the IRIS Toxicological Review of Benzo[a]pyrene are posted on this site. EPA is undertaking an update of the Integrated Risk Information System (IRIS) health assessment for benzo[a]pyrene (BaP). The outcome of this project is an updated Toxicological Review and IRIS Summary for BaP that will be entered into the IRIS database.

  10. Selective discrimination of cyclodextrin diols using cyclic sulfates

    DEFF Research Database (Denmark)

    Petrillo, Marta; Marinescu, Lavinia; Rousseau, Cyril

    2009-01-01

    A method for selective monofunctionalition of readily available cyclodextrin diols (2(A-F),3(A-F),6(B,C,E,F)-hexadeca-O-benzyl-alpha-cyclodextrin and 2(A-G),3(A-G),6(B,C,E-G)-nonadeca-O-benzyl-beta-cyclodextrin) by regioselective nucleophilic opening of their cyclic sulfates is presented. Although...

  11. Sequential enzymatic epoxidation involved in polyether lasalocid biosynthesis.

    Science.gov (United States)

    Minami, Atsushi; Shimaya, Mayu; Suzuki, Gaku; Migita, Akira; Shinde, Sandip S; Sato, Kyohei; Watanabe, Kenji; Tamura, Tomohiro; Oguri, Hiroki; Oikawa, Hideaki

    2012-05-02

    Enantioselective epoxidation followed by regioselective epoxide opening reaction are the key processes in construction of the polyether skeleton. Recent genetic analysis of ionophore polyether biosynthetic gene clusters suggested that flavin-containing monooxygenases (FMOs) could be involved in the oxidation steps. In vivo and in vitro analyses of Lsd18, an FMO involved in the biosynthesis of polyether lasalocid, using simple olefin or truncated diene of a putative substrate as substrate mimics demonstrated that enantioselective epoxidation affords natural type mono- or bis-epoxide in a stepwise manner. These findings allow us to figure out enzymatic polyether construction in lasalocid biosynthesis. © 2012 American Chemical Society

  12. Protective Effect of Mulberry (Morus alba L.) Extract against Benzo[a]pyrene Induced Skin Damage through Inhibition of Aryl Hydrocarbon Receptor Signaling.

    Science.gov (United States)

    Woo, Hyunju; Lee, JungA; Park, Deokhoon; Jung, Eunsun

    2017-12-20

    Benzo[a]pyrene (B[a]P), a type of polycyclic aromatic hydrocarbon, is present in the atmosphere surrounding our environment. Although B[a]P is a procarcinogen, enzymatically metabolized benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) could intercalate into DNA to form bulky BPDE-DNA adducts as an ultimate carcinogenic product in human keratinocytes. The aim of this study was to evaluate the protective effect of mulberry extract, purified from the fruit of Morus Alba L., on B[a]P-induced cytotoxicity in human keratinocytes and its mechanisms of action. In this study, we confirmed that B[a]P induced nuclear translocation and the activation of aryl hydrocarbon receptor (AhR) were decreased by pretreatment of mulberry extract. Mulberry extract could decrease DNA damage through the suppression of B[a]P derived DNA adduct formation and restoration of cell cycle retardation at S phase in a dose-dependent manner. Additionally, cyanidin-3-glucoside (C3G), a major active compound of mulberry extract, showed biological activities to protect the cells from B[a]P exposure, similar to the effectivity of the mulberry extract. These results indicated that the inhibitory effect of C3G against B[a]P inducing skin cancer is attributable to repress the AhR signaling pathway.

  13. Omeprazole increases the efficacy of a soluble epoxide hydrolase inhibitor in a PGE2 induced pain model

    International Nuclear Information System (INIS)

    Goswami, Sumanta Kumar; Inceoglu, Bora; Yang, Jun; Wan, Debin; Kodani, Sean D.; Trindade da Silva, Carlos Antonio; Morisseau, Christophe; Hammock, Bruce D.

    2015-01-01

    Epoxyeicosatrienoic acids (EETs) are potent endogenous analgesic metabolites produced from arachidonic acid by cytochrome P450s (P450s). Metabolism of EETs by soluble epoxide hydrolase (sEH) reduces their activity, while their stabilization by sEH inhibition decreases both inflammatory and neuropathic pain. Here, we tested the complementary hypothesis that increasing the level of EETs through induction of P450s by omeprazole (OME), can influence pain related signaling by itself, and potentiate the anti-hyperalgesic effect of sEH inhibitor. Rats were treated with OME (100 mg/kg/day, p.o., 7 days), sEH inhibitor TPPU (3 mg/kg/day, p.o.) and OME (100 mg/kg/day, p.o., 7 days) + TPPU (3 mg/kg/day, p.o., last 3 days of OME dose) dissolved in vehicle PEG400, and their effect on hyperalgesia (increased sensitivity to pain) induced by PGE 2 was monitored. While OME treatment by itself exhibited variable effects on PGE 2 induced hyperalgesia, it strongly potentiated the effect of TPPU in the same assay. The significant decrease in pain with OME + TPPU treatment correlated with the increased levels of EETs in plasma and increased activities of P450 1A1 and P450 1A2 in liver microsomes. The results show that reducing catabolism of EETs with a sEH inhibitor yielded a stronger analgesic effect than increasing generation of EETs by OME, and combination of both yielded the strongest pain reducing effect under the condition of this study. - Highlights: • The soluble epoxide hydrolase (sEH) inhibitor TPPU is anti-hyperalgesic. • Omeprazole potentiates the anti-hyperalgesic actions of TPPU. • This potentiation is associated with increased P450 activity. • The potentiation is associated with an increase in fatty acid epoxide/diol ratio. • Joint use of sEH inhibitors and P450 inducers could result in drug–drug interactions.

  14. Alterations in the metabolism of benzo[a]pyrene in syrian hamster embryo (SHE) cells pretreated with phenolic antioxidants

    International Nuclear Information System (INIS)

    Strniste, G.F.; Okinaka, R.T.; Chen, D.J.

    1983-01-01

    Inhibition of chemical- or radiation-induced neoplasia has been observed in animals whose diets were supplemented with antioxidants commonly used as food additives. Inhibition of the carcinogenicity of benzo[a]pyrene (BaP) or of 7,12-dimenthylbenz[a]anthracene (DMBA) - in rats has been achieved by the addition of the phenolic antioxidants butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT) to the diet. Our data suggest that in SHE cells antioxidants inhibit the overall metabolism of BaP to its various oxidized moieties including 7,8-diol- and 7,8,9,10-tetrol-BaP. A plausible explanation for our results with SHE cells is that the antioxidants interact directly with AHH, thus inhibiting AHH metabolic capacity. From analysis of nuclear material from SHE cells (+- antioxidants) incubated for 36 hours with BaP at 1 μg/ml, it is calculated that 4.6, 2.4 and 2.9 pmol BaP are bound to the DNA isolated from 10 7 nuclei of control, BHA-(20 μg/ml) and p-MP-(10 μg/ml) treated cultures, respectively

  15. The Epoxidation of Limonene over the TS-1 and Ti-SBA-15 Catalysts

    Directory of Open Access Journals (Sweden)

    Agnieszka Wróblewska

    2014-11-01

    Full Text Available Limonene belongs to a group of very important intermediates used in the production of fine chemicals. This monoterpene compound can be obtained from peels of oranges or lemon which are a (biomass waste from the orange juice industry. Thus, limonene is a renewable, easy available and a relatively cheap compound. This work presents preliminary studies on the process of limonene epoxidation over zeolite type catalysts such as: TS-1 and Ti-SBA-15. In these studies methanol was used as a solvent and as an oxidizing agent a 60 wt % hydrogen peroxide solution was applied. The activity of each catalyst was investigated for four chosen temperatures (0 °C, 40 °C, 80 °C and 120 °C. The reaction time was changed from 0.5 to 24 h. For each catalyst the most beneficial conditions (the appropriate temperature and the reaction time have been established. The obtained results were compared and the most active catalyst was chosen. These studies have also shown different possible ways of limonene transformation, not only in the direction of 1,2-epoxylimonene and its corresponding diol, but also in direction of carveol, carvone and perillyl alcohol—compounds with a lot of applications. The possible mechanisms of formation of the allylic oxidation products were proposed.

  16. Prediction of metabolites of epoxidation reaction in MetaTox.

    Science.gov (United States)

    Rudik, A V; Dmitriev, A V; Bezhentsev, V M; Lagunin, A A; Filimonov, D A; Poroikov, V V

    2017-10-01

    Biotransformation is a process of the chemical modifications which may lead to the reactive metabolites, in particular the epoxides. Epoxide reactive metabolites may cause the toxic effects. The prediction of such metabolites is important for drug development and ecotoxicology studies. Epoxides are formed by some oxidation reactions, usually catalysed by cytochromes P450, and represent a large class of three-membered cyclic ethers. Identification of molecules, which may be epoxidized, and indication of the specific location of epoxide functional group (which is called SOE - site of epoxidation) are important for prediction of epoxide metabolites. Datasets from 355 molecules and 615 reactions were created for training and validation. The prediction of SOE is based on a combination of LMNA (Labelled Multilevel Neighbourhood of Atom) descriptors and Bayesian-like algorithm implemented in PASS software and MetaTox web-service. The average invariant accuracy of prediction (AUC) calculated in leave-one-out and 20-fold cross-validation procedures is 0.9. Prediction of epoxide formation based on the created SAR model is included as the component of MetaTox web-service ( http://www.way2drug.com/mg ).

  17. Recent trends in ring opening of epoxides with sulfur nucleophiles.

    Science.gov (United States)

    Ahmad, Sajjad; Zahoor, Ameer Fawad; Naqvi, Syed Ali Raza; Akash, Muhammad

    2018-02-01

    Thiolysis of epoxides offers an efficient and simple synthetic approach to access [Formula: see text]-hydroxy sulfides which are valuable scaffold in the synthesis of various important molecules in medicinal chemistry. This review article presents a recent compilation of the synthetic approaches developed after 2000 for the thiolysis of epoxides.

  18. Ring opening of epoxides with C-nucleophiles.

    Science.gov (United States)

    Faiz, Sadia; Zahoor, Ameer Fawad

    2016-11-01

    Ring opening of epoxides has been an area of interest for organic chemists, owing to their reactivity toward nucleophiles. Such reactions yield important products depending on the type of nucleophiles used. This review article covers the synthetic approaches (1991-2015) used for the ring opening of epoxides via carbon nucleophiles.

  19. Mechanism of titanocene-mediated epoxide opening through homolytic substitution

    DEFF Research Database (Denmark)

    Gansäuer, Andreas; Barchuk, Andriy; Keller, Florian

    2007-01-01

    −titanocene complexes, the transition states of epoxide opening, and the β-titanoxy radicals formed. The results obtained provide a structural basis for the understanding of the factors determining the regioselectivity of ring opening and match the experimentally determined values. By employing substituted titanocenes...... of monomeric and dimeric Ti(III) species was found to be strongly affected by the exact steric conditions. The overall rate constants of the reductive epoxide opening were determined for the first time. These data were employed as the basis for computational studies of the structure and energies of the epoxide...... even more selective epoxide openings could be realized. Moreover, by properly adjusting the steric demands of the catalysts and the substrates the first examples of reversible epoxide openings were designed....

  20. Construction and characterisation of a genetically engineered Escherichia coli strain for the epoxide hydrolase-catalysed kinetic resolution of epoxides

    NARCIS (Netherlands)

    Visser, H.; Oliveira Vil Filho, de M.; Liese, A.; Weijers, C.A.G.M.; Verdoes, J.C.

    2003-01-01

    The Rhodotorula glutinis epoxide hydrolase, Eph1, was produced in the heterologous host Escherichia coli BL21(DE3) in order to develop a highly effective epoxide hydrolysis system. A 138-fold increase in Eph1 activity was found in cell extracts of the recombinant E. coli when compared to cell

  1. Microdroplets Accelerate Ring Opening of Epoxides

    Science.gov (United States)

    Lai, Yin-Hung; Sathyamoorthi, Shyam; Bain, Ryan M.; Zare, Richard N.

    2018-03-01

    The nucleophilic opening of an epoxide is a classic organic reaction that has widespread utility in both academic and industrial applications. We have studied the reaction of limonene oxide with morpholine to form 1-methyl-2-morpholino-4-(prop-1-en-2-yl) cyclohexan-1-ol in bulk solution and in electrosprayed microdroplets with a 1:1 v/v water/methanol solvent system. We find that even after 90 min at room temperature, there is no product detected by nuclear magnetic resonance spectroscopy in bulk solution whereas in room-temperature microdroplets (2-3 μm in diameter), the yield is already 0.5% in a flight time of 1 ms as observed by mass spectrometry. This constitutes a rate acceleration of 105 in the microdroplet environment, if we assume that as much as 5% of product is formed in bulk after 90 min of reaction time. We examine how the reaction rate depends on droplet size, solvent composition, sheath gas pressure, and applied voltage. These factors profoundly influence the extent of reaction. This dramatic acceleration is not limited to just one system. We have also found that the nucleophilic opening of cis-stilbene oxide by morpholine is similarly accelerated. Such large acceleration factors in reaction rates suggest the use of microdroplets for ring opening of epoxides in other systems, which may have practical significance if such a procedure could be scaled. [Figure not available: see fulltext.

  2. Microdroplets Accelerate Ring Opening of Epoxides

    Science.gov (United States)

    Lai, Yin-Hung; Sathyamoorthi, Shyam; Bain, Ryan M.; Zare, Richard N.

    2018-05-01

    The nucleophilic opening of an epoxide is a classic organic reaction that has widespread utility in both academic and industrial applications. We have studied the reaction of limonene oxide with morpholine to form 1-methyl-2-morpholino-4-(prop-1-en-2-yl) cyclohexan-1-ol in bulk solution and in electrosprayed microdroplets with a 1:1 v/ v water/methanol solvent system. We find that even after 90 min at room temperature, there is no product detected by nuclear magnetic resonance spectroscopy in bulk solution whereas in room-temperature microdroplets (2-3 μm in diameter), the yield is already 0.5% in a flight time of 1 ms as observed by mass spectrometry. This constitutes a rate acceleration of 105 in the microdroplet environment, if we assume that as much as 5% of product is formed in bulk after 90 min of reaction time. We examine how the reaction rate depends on droplet size, solvent composition, sheath gas pressure, and applied voltage. These factors profoundly influence the extent of reaction. This dramatic acceleration is not limited to just one system. We have also found that the nucleophilic opening of cis-stilbene oxide by morpholine is similarly accelerated. Such large acceleration factors in reaction rates suggest the use of microdroplets for ring opening of epoxides in other systems, which may have practical significance if such a procedure could be scaled. [Figure not available: see fulltext.

  3. Flow cytometric measurement of the metabolism of benzo [a] pyrene by mouse liver cells in culture

    International Nuclear Information System (INIS)

    Bartholomew, J.C.; Wade, C.G.; Dougherty, K.

    1984-01-01

    The metabolism of benzo[a]pyrene in individual cells was monitored by flow cytometry. The measurements are based on the alterations that occur in the fluorescence emission spectrum of benzo[a]pyrene when it is converted to various metabolities. Using present instrumentation the technique could easily detect 1 x 10/sup 6/ molecules per cells of benzo [a]pyrene and 1 x 10/sup 7/ molecules per cell of the diol epoxide. The analysis of C3H IOT 1/2 mouse fibroblasts growing in culture indicated that there was heterogeneity in the conversion of the parent compound into diol epoxide derivative suggesting that some variation in sensitivity to transformation by benzo[a]pyrene may be due to differences in cellular metabolism

  4. Investigation of benzo(a)pyrene-globin adducts

    Energy Technology Data Exchange (ETDEWEB)

    Wallin, H; Jeffre, A M; Santella, R M

    1987-05-01

    The nature of the adducts formed between benzo(a)pyrene (BP) and globin were investigated in animals treated with (/sup 3/H)BP. Modification levels on globin were determined by radioactivity measurements. Since BP tetraols can be released from benzo(a)pyrene diol epoxide modified protein and DNA by acid treatment, globin samples were treated with acid, released tetraols separated by HPLC and quantitated by scintillation counting. In addition, acid released material was measured in competitive enzyme linked immunosorbent assay (ELISA) using antibodies which recognize BP tetraols. Both measurements indicate that only 2% of bound radioactivity could be released as free BP tetraols. These studies indicate that benzo(a)pyrene diol epoxide may not be the major metabolite of BP involved in globin binding. (author). 14 refs.

  5. Swelling behaviour in n-pentane and mechanical properties of epoxidized natural rubber with different epoxide content

    Science.gov (United States)

    Kinasih, N. A.; Fathurrohman, M. I.; Winarto, D. A.

    2017-07-01

    Epoxidized natural rubber (ENR) with different level of epoxidation (i.e. 10, 20, 30, 40 and 50 mol% indicated as ENR ENR10, ENR20, ENR30, ENR40 and ENR50, respectively) were prepared. They were then vulcanized by using efficient system vulcanization. The effect of epoxide content on curing characteristic, swelling and mechanical properties in N-pentane was investigated. The Attenuated Resonance Fourier Transform Infrared (ATR-FTIR) and H-Nuclear Magnetic Resonance (H-NMR) were used to determine the epoxidation level. Glass transition (Tg) of ENR samples was determined by using Direct Scanning Calorimetry (DSC). The result revealed that the resistance of ENR in N-pentane increased with increasing epoxidation level, which indicated by decreasing equilibrium mol uptake and diffusion coefficient. The compression set of ENR and aging resistance increased with increasing epoxide content, except ENR50 was due to ENR 50 have two Tg value. However, the value of hardness and tensile strength were not effected by epoxidation level.

  6. Enantioselective Epoxide Polymerization Using a Bimetallic Cobalt Catalyst

    KAUST Repository

    Thomas, Renee M.

    2010-11-24

    A highly active enantiopure bimetallic cobalt complex was explored for the enantioselective polymerization of a variety of monosubstituted epoxides. The polymerizations were optimized for high rates and stereoselectivity, with s-factors (kfast/kslow) for most epoxides exceeding 50 and some exceeding 300, well above the threshold for preparative utility of enantiopure epoxides and isotactic polyethers. Values for mm triads of the resulting polymers are typically greater than 95%, with some even surpassing 98%. In addition, the use of a racemic catalyst allowed the preparation of isotactic polyethers in quantitative yields. The thermal properties of these isotactic polyethers are presented, with many polymers exhibiting high T m values. This is the first report of the rapid synthesis of a broad range of highly isotactic polyethers via the enantioselective polymerization of racemic epoxides. © 2010 American Chemical Society.

  7. Epoxide reduction with hydrazine on graphene: a first principles study.

    Science.gov (United States)

    Kim, Min Chan; Hwang, Gyeong S; Ruoff, Rodney S

    2009-08-14

    Mechanisms for epoxide reduction with hydrazine on a single-layer graphene sheet are examined using quantum mechanical calculations within the framework of gradient-corrected spin-polarized density-functional theory. We find that the reduction reaction is mainly governed by epoxide ring opening which is initiated by H transfer from hydrazine or its derivatives. In addition, our calculations suggest that the epoxide reduction by hydrazine may predominantly follow a direct Eley-Rideal mechanism rather than a Langmuir-Hinshelwood mechanism. We also discuss the generation of various hydrazine derivatives during the reduction of graphene oxide with hydrazine and their potential contribution to lowering the barrier height of epoxide ring opening.

  8. Novel microbial epoxide hydrolases for biohydrolysis of glycidyl derivatives

    Czech Academy of Sciences Publication Activity Database

    Kotík, Michael; Břicháč, Jiří; Kyslík, Pavel

    2005-01-01

    Roč. 120, - (2005), s. 364-375 ISSN 0168-1656 Institutional research plan: CEZ:AV0Z5020903 Keywords : screening * epoxide hydrolase * biotransformation Subject RIV: EE - Microbiology, Virology Impact factor: 2.687, year: 2005

  9. Alternating copolymerization of epoxides with anhydrides initiated by organic bases

    Czech Academy of Sciences Publication Activity Database

    Hošťálek, Z.; Trhlíková, Olga; Walterová, Zuzana; Martinez, T.; Peruch, F.; Cramail, H.; Merna, J.

    2017-01-01

    Roč. 88, March (2017), s. 433-447 ISSN 0014-3057 Institutional support: RVO:61389013 Keywords : copolymerization * epoxides * anhydrides Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.531, year: 2016

  10. Enantioselective Epoxide Polymerization Using a Bimetallic Cobalt Catalyst

    KAUST Repository

    Thomas, Renee M.; Widger, Peter C. B.; Ahmed, Syud M.; Jeske, Ryan C.; Hirahata, Wataru; Lobkovsky, Emil B.; Coates, Geoffrey W.

    2010-01-01

    A highly active enantiopure bimetallic cobalt complex was explored for the enantioselective polymerization of a variety of monosubstituted epoxides. The polymerizations were optimized for high rates and stereoselectivity, with s-factors (kfast/kslow) for most epoxides exceeding 50 and some exceeding 300, well above the threshold for preparative utility of enantiopure epoxides and isotactic polyethers. Values for mm triads of the resulting polymers are typically greater than 95%, with some even surpassing 98%. In addition, the use of a racemic catalyst allowed the preparation of isotactic polyethers in quantitative yields. The thermal properties of these isotactic polyethers are presented, with many polymers exhibiting high T m values. This is the first report of the rapid synthesis of a broad range of highly isotactic polyethers via the enantioselective polymerization of racemic epoxides. © 2010 American Chemical Society.

  11. Determination of 3-Monochloropropane-1,2-diol and 2-Monochloropropane-1,3-diol (MCPD) Esters and Glycidyl Esters by Microwave Extraction in Different Foodstuffs.

    Science.gov (United States)

    Marc, Corinne; Drouard-Pascarel, Valérie; Rétho, Cécile; Janvion, Patrice; Saltron, Frédéric

    2016-06-01

    This paper describes a method for the determination of 3-monochloropropane-1,2-diol and 2-monochloropropane-1,3-diol (MCPD) esters and glycidyl esters in various foodstuffs, which are isolated using microwave extraction. The next step is based on alkaline-catalyzed ester cleavage. The released glycidol is transformed into monobromopropanediol (MBPD). All compounds are derivatized in free diols (MCPD and MBPD) with phenylboronic acid and analyzed by gas chromatography-mass spectrometry (GC-MS). The method was validated for oils with a limit of quantitation (LOQ) of 0.1 mg/kg, for chips and crisps with a LOQ of 0.02 mg/kg, and for infant formula with a LOQ of 0.0025 mg/L. Recoveries of each sample were controlled by standard addition on extracts before derivatization. Quantitation was performed by the addition of isotopically labeled glycidyl and 3-monochloropropane-1,2-diol (3-MCPD) esters.

  12. Design and Synthesis of 2-Alkylpyrimidine-4,6-diol and 6-Alkylpyridine-2,4-diol as Potent GPR84 Agonists.

    Science.gov (United States)

    Liu, Yang; Zhang, Qing; Chen, Lin-Hai; Yang, Hui; Lu, Wei; Xie, Xin; Nan, Fa-Jun

    2016-06-09

    A series of alkylpyrimidine-4,6-diol derivatives were designed and synthesized as novel GRP84 agonists based on a high-throughput screening (HTS) hit 1. 6-Nonylpyridine-2,4-diol was identified as the most potent agonist of GPR84 reported so far, with an EC50 of 0.189 nM. These novel GPR84 agonists will provide valuable tools for the study of the physiological functions of GPR84.

  13. Baseline levels of benzo(a)pyrene in southern California mussels

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, B P [Univ. of British Columbia, Vancouver; Young, D R

    1976-12-01

    Marine mussels accumulate the carcinogen benzo(a)-pyrene from contaminated environments. Baseline studies in California indicate that levels of the carcinogen in mussels are at or near zero, except in areas of human activity. This finding runs counter to previous suggestions that benzo(a)pyrene is widely distributed in marine organisms.

  14. Development of Long Chain Alkyl Diol δD as a Paleohydrological Proxy

    Science.gov (United States)

    Neary, A.; Russell, J. M.; Cordero, D.

    2017-12-01

    Understanding past hydroclimate is important to better understand and prepare for future climate changes. Past hydrological change is often studied through δD of lipid biomarkers preserved in sediment. Long chain alkyl diols are lipid biomarkers that are widely distributed in lake and marine sediments. These compounds are produced by certain species of diatoms and algae (Eustigmatophytes). Diol δD is expected to record relative precipitation and evaporation, and other lake surface processes. This would be a valuable addition to the repertoire of organic compounds used for hydrologic reconstruction, such as leaf waxes which record precipitation. While long chain alkyl diols present an opportunity to expand the range of compounds available for compound specific isotope analysis, studies of diol δD are scarce. This study aims to compare diol and leaf wax δD records from Lake Tanganyika spanning approximately the past 20 kyrs in order to elucidate the controlling factors on diol δD values and evaluate the effectiveness of such a record as a paleohydrological proxy. If viable, diol δD records could be used to gain a deeper understanding of past climates. δD leaf wax records have been previously measured in Lake Tanganyika cores (Tierney et al., 2008). This study measures δD of long chain alkyl diols from the same cores in order to compare records. Our current measurements show significant deviations of the diol record from the leaf wax record at times when large magnitude changes in the leaf wax record are occurring, such as a less pronounced Younger Dryas and a more gradual decrease in δD values after Heinrich 1 than the sudden shift expressed by the leaf wax record. In addition to generating a diol δD record through time at Lake Tanganyika, we have also measured diol δD in surface sediments from several east African lakes in order to examine the potential for a proxy calibration. A positive correlation between diol and lake water δD has been observed

  15. Studies on the analysis of benzo(a)pyrene and its metabolites in biological samples by using high performance liquid chromatography/fluorescence detection and gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Lee, Won; Hong, Jee Eun; Shin, Hye Seung; Pyo, Hee Soo; Kim, Yun Je

    2003-01-01

    An analytical method the determination of benzo(a)pyrene (BaP) and its hydroxylated metabolites, 1-hydroxybenzo(a)pyrene (1-OHBaP), 3-hydroxybenzo(a)pyrene (3-OHBaP), benzo(a)pyrene-4,5-dihydrodial(4,5-diolBaP) and benzo(a)pyrene-7,8-dihydrodiol (7,8-diolBaP), in rat urine and plasma has been developed by HPLC/FLD and GC/MS. The derivatization with alkyl iodide was employed to improve the resolution and the detection of two mono hydroxylated metabolites, 1-OHBaP and 3-OHBaP, in LC and GC. BaP and its four metabolites in spiked urine were successfully separated by gradient elution on reverse phase ODS C 18 column (4.6 mm I.D., 100 mm length, particle size 5μm) using a binary mixture of MeOH/H 2 O (85/15, v/v) as mobile phase after ethylation at 90 .deg. C for 10 min. The extraction recoveries of BaP and its metabolites in spiked samples with liquid-liquid extraction, which was better than solid phase extraction, were in the range of 90.3-101.6% in n-hexane for urine and 95.7-106.3% in acetone for plasma, respectively. The calibration curves has shown good linearity with the correlation coefficients (R 2 ) varying from 0.992 to 1.000 for urine and from 0.996 to 1.000 for plasma, respectively. The detection limits of all analytes were obtained in the range of 0.01-0.1 ng/mL for urine and 0.1-0.4ng/mL for plasma, respectively. The metabolites of BaP were excreted as mono hydroxy and dihydrodiol forms after intraperitoneal infection of 20 mg/kg of BaP to rats. The total amounts of BaP and four metabolites excreted in dosed rat urine were 3.79 ng over the 0 - 96 hr period from administration and the excretional recovery was less than 0.065% of the injection amounts of BaP. The proposed method was successfully applied to the determination of BaP and its hydroxylated metabolites in rat urine and plasma for the pharmacokinetic studies

  16. Omeprazole increases the efficacy of a soluble epoxide hydrolase inhibitor in a PGE{sub 2} induced pain model

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, Sumanta Kumar; Inceoglu, Bora; Yang, Jun; Wan, Debin; Kodani, Sean D. [Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA (United States); Trindade da Silva, Carlos Antonio [Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA (United States); Department of Genetics and Biochemistry, Federal University of Uberlandia, MG (Brazil); Morisseau, Christophe [Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA (United States); Hammock, Bruce D., E-mail: bdhammock@ucdavis.edu [Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA (United States)

    2015-12-15

    Epoxyeicosatrienoic acids (EETs) are potent endogenous analgesic metabolites produced from arachidonic acid by cytochrome P450s (P450s). Metabolism of EETs by soluble epoxide hydrolase (sEH) reduces their activity, while their stabilization by sEH inhibition decreases both inflammatory and neuropathic pain. Here, we tested the complementary hypothesis that increasing the level of EETs through induction of P450s by omeprazole (OME), can influence pain related signaling by itself, and potentiate the anti-hyperalgesic effect of sEH inhibitor. Rats were treated with OME (100 mg/kg/day, p.o., 7 days), sEH inhibitor TPPU (3 mg/kg/day, p.o.) and OME (100 mg/kg/day, p.o., 7 days) + TPPU (3 mg/kg/day, p.o., last 3 days of OME dose) dissolved in vehicle PEG400, and their effect on hyperalgesia (increased sensitivity to pain) induced by PGE{sub 2} was monitored. While OME treatment by itself exhibited variable effects on PGE{sub 2} induced hyperalgesia, it strongly potentiated the effect of TPPU in the same assay. The significant decrease in pain with OME + TPPU treatment correlated with the increased levels of EETs in plasma and increased activities of P450 1A1 and P450 1A2 in liver microsomes. The results show that reducing catabolism of EETs with a sEH inhibitor yielded a stronger analgesic effect than increasing generation of EETs by OME, and combination of both yielded the strongest pain reducing effect under the condition of this study. - Highlights: • The soluble epoxide hydrolase (sEH) inhibitor TPPU is anti-hyperalgesic. • Omeprazole potentiates the anti-hyperalgesic actions of TPPU. • This potentiation is associated with increased P450 activity. • The potentiation is associated with an increase in fatty acid epoxide/diol ratio. • Joint use of sEH inhibitors and P450 inducers could result in drug–drug interactions.

  17. Regioselective Acylation of Diols and Triols: The Cyanide Effect.

    Science.gov (United States)

    Peng, Peng; Linseis, Michael; Winter, Rainer F; Schmidt, Richard R

    2016-05-11

    Central topics of carbohydrate chemistry embrace structural modifications of carbohydrates and oligosaccharide synthesis. Both require regioselectively protected building blocks that are mainly available via indirect multistep procedures. Hence, direct protection methods targeting a specific hydroxy group are demanded. Dual hydrogen bonding will eventually differentiate between differently positioned hydroxy groups. As cyanide is capable of various kinds of hydrogen bonding and as it is a quite strong sterically nondemanding base, regioselective O-acylations should be possible at low temperatures even at sterically congested positions, thus permitting formation and also isolation of the kinetic product. Indeed, 1,2-cis-diols, having an equatorial and an axial hydroxy group, benzoyl cyanide or acetyl cyanide as an acylating agent, and DMAP as a catalyst yield at -78 °C the thermodynamically unfavorable axial O-acylation product; acyl migration is not observed under these conditions. This phenomenon was substantiated with 3,4-O-unproteced galacto- and fucopyranosides and 2,3-O-unprotected mannopyranosides. Even for 3,4,6-O-unprotected galactopyranosides as triols, axial 4-O-acylation is appreciably faster than O-acylation of the primary 6-hydroxy group. The importance of hydrogen bonding for this unusual regioselectivity could be confirmed by NMR studies and DFT calculations, which indicate favorable hydrogen bonding of cyanide to the most acidic axial hydroxy group supported by hydrogen bonding of the equatorial hydroxy group to the axial oxygen. Thus, the "cyanide effect" is due to dual hydrogen bonding of the axial hydroxy group which enhances the nucleophilicity of the respective oxygen atom, permitting an even faster reaction for diols than for mono-ols. In contrast, fluoride as a counterion favors dual hydrogen bonding to both hydroxy groups leading to equatorial O-acylation.

  18. Catalytic asymmetric epoxidation of alpha,beta-unsaturated amides: efficient synthesis of beta-aryl alpha-hydroxy amides using a one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process.

    Science.gov (United States)

    Nemoto, Tetsuhiro; Kakei, Hiroyuki; Gnanadesikan, Vijay; Tosaki, Shin-Ya; Ohshima, Takashi; Shibasaki, Masakatsu

    2002-12-11

    The catalytic asymmetric epoxidation of alpha,beta-unsaturated amides using Sm-BINOL-Ph3As=O complex was succeeded. Using 5-10 mol % of the asymmetric catalyst, a variety of amides were epoxidized efficiently, yielding the corresponding alpha,beta-epoxy amides in up to 99% yield and in more than 99% ee. Moreover, the novel one-pot tandem process, one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process, was developed. This method was successfully utilized for the efficient synthesis of beta-aryl alpha-hydroxy amides, including beta-aryllactyl-leucine methyl esters. Interestingly, it was found that beneficial modifications on the Pd catalyst were achieved by the constituents of the first epoxidation, producing a more suitable catalyst for the Pd-catalyzed epoxide opening reaction in terms of chemoselectivity.

  19. Synergistic dual activation catalysis by palladium nanoparticles for epoxide ring opening with phenols.

    Science.gov (United States)

    Seth, Kapileswar; Roy, Sudipta Raha; Pipaliya, Bhavin V; Chakraborti, Asit K

    2013-07-04

    Synergistic dual activation catalysis has been devised for epoxide phenolysis wherein palladium nanoparticles induce electrophilic activation via coordination with the epoxide oxygen followed by nucleophilic activation through anion-π interaction with the aromatic ring of the phenol, and water (reaction medium) also renders assistance through 'epoxide-phenol' dual activation.

  20. Sulfuric acid as a catalyst for ring-opening of biobased bis-epoxides

    Science.gov (United States)

    Vegetable oils can be relatively and easily transformed into bio-based epoxides. Because of this, the acid-catalyzed epoxide ring-opening has been explored for the preparation of bio-based lubricants and polymers. Detailed model studies are carried out only with mono-epoxide made from methyl oleate,...

  1. Biocompatibility of epoxidized styrene-butadiene-styrene block copolymer membrane

    International Nuclear Information System (INIS)

    Yang, Jen Ming; Tsai, Shih Chang

    2010-01-01

    Styrene-butadiene-styrene block copolymer (SBS) membrane was prepared by solution casting method and then was epoxidized with peroxyformic acid generated in situ to yield the epoxidized styrene-butadiene-styrene block copolymer membrane (ESBS). The structure and properties of ESBS were characterized with infrared spectroscopy, Universal Testing Machine, differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA). The performances of contact angle, water content, protein adsorption, and water vapor transmission rate on ESBS membrane were determined. After epoxidation, the hydrophilicity of the membrane increased. The water vapor transmission rate of ESBS membrane is similar to human skin. The biocompatibility of ESBS membrane was evaluated with the cell culture of fibroblasts on the membrane. It revealed that the cells not only remained viable but also proliferated on the surface of the various ESBS membranes and the population doubling time for fibroblast culture decreased.

  2. Electrocatalytic aerobic epoxidation of alkenes: Experimental and DFT investigation

    International Nuclear Information System (INIS)

    Magdesieva, Tatiana V.; Borisova, Nataliya E.; Dolganov, Alexander V.; Ustynyuk, Yuri A.

    2012-01-01

    A new method for electrocatalytic aerobic epoxidation of alkenes catalyzed by binuclear Cu(II) complexes with azomethine ligands based on 2,6-diformyl-4-tert-butylphenol is described. In acetonitrile–water (5%), at the potential of Cu II /Cu I redox couple (–0.8 V vs. Ag/AgCl/KCl) at room temperature the epoxide is obtained in an average yield of around 50%. Contrary to the majority of known epoxidations, no strong oxidants are involved and no free hydrogen peroxide is formed in the reaction, thus making it ecologically friendly. The DFT quantum-chemical modeling of the reaction mechanism revealed that a copper hydroperoxo-complex rather than hydrogen peroxide or a copper oxo-complex oxidizes alkene. The process is very selective since neither products of hydroxylation of benzene ring in styrene nor of allylic oxidation of cyclohexene were detected.

  3. Synthesis and Tribological Studies of Branched Alcohol Derived Epoxidized Biodiesel

    Directory of Open Access Journals (Sweden)

    Qinggong Ren

    2015-09-01

    Full Text Available The optimization and kinetics of the ring-opening reaction of an epoxidized biodiesel (epoxidized rapeseed oil methyl ester (EBD with 2-ethyl hexanol (2-EH were studied. The determined optimum conditions were 4:1 2-EH/oil molar ratio, 90 °C, 18 h, and 7 wt % of Amberlyst D001 (dry catalyst; the product’s oxirane oxygen content was 0.081% with 38.32 mm2/s viscosity at 40 °C. The catalyst retained its high catalytic power after recycling five times. Furthermore, the determined non-catalyzed activation energy was 76 kJ·mol−1 and 54 kJ·mol−1 with the D001 resin catalyst. The product’s chemical structure was investigated through FT-IR and 1H NMR. The viscosity, flash point, pour point, and anti-wear properties of the product were improved compared with those of epoxidized biodiesel.

  4. The oxidation of copper catalysts during ethylene epoxidation.

    Science.gov (United States)

    Greiner, M T; Jones, T E; Johnson, B E; Rocha, T C R; Wang, Z J; Armbrüster, M; Willinger, M; Knop-Gericke, A; Schlögl, R

    2015-10-14

    The oxidation of copper catalysts during ethylene epoxidation was characterized using in situ photoemission spectroscopy and electron microscopy. Gas chromatography, proton-transfer reaction mass spectrometry and electron-ionization mass spectrometry were used to characterize the catalytic properties of the oxidized copper. We find that copper corrodes during epoxidation in a 1 : 1 mixture of oxygen and ethylene. The catalyst corrosion passes through several stages, beginning with the formation of an O-terminated surface, followed by the formation of Cu2O scale and eventually a CuO scale. The oxidized catalyst exhibits measurable activity for ethylene epoxidation, but with a low selectivity of 8/2500) Cu2O forms and eventually covers the surface.

  5. Epoxidation of limonene over Ti MCM 41 and Ti BETA

    International Nuclear Information System (INIS)

    Cubillos Lobo, Jairo Antonio; Gonzalez Rodriguez, Lina Maria; Montes de Correa, Consuelo

    2002-01-01

    Ti MCM 41 were synthesized and evaluated in the epoxidation of limonene, using peroxide of hydrogen (H 2 O) as agent oxidizer. The characteristic hexagonal phase of Ti MCM 41 was obtained by heating the precursor gel during three days at 100 centigrade degrees. Further heating up to ten days leads to a decrease of this phase. The increase (Ti) in the synthesis gel also decreases that phase. The increase of Ti in the synthesis gel also decreases that phase UV VIS and FTIR spectroscopy indicates that Ti was incorporated in the lattice of Ti MCM 41 as well as, in Ti BETA. SEM micrographs of Ti MCM 41 show that the morphology changes with the Ti loading. Ti MCM 41 was most active than Ti BETA for limonene epoxidation even though both show high selectivity to epoxides

  6. A strategy for position-selective epoxidation of polyprenols.

    Science.gov (United States)

    Gnanadesikan, Vijay; Corey, E J

    2008-06-25

    An effective strategy has been developed for the efficient site-selective epoxidation of poylolefinic isoprenoid alcohols, based on the use of an internal control element for intramolecular reaction. The approach is illustrated by application to a series of polyisoprenoid alcohols (polyprenols) at substrate concentration of 0.5 mM. With polyprenol substrates having the hydroxyl function at one terminus, the internal epoxidation can be directed at the double bond of the polyprenol, which is either four or five away from the terminal hydroxyprenyl subunit.

  7. Bakers yeast-mediated transformations of alpha-keto epoxides

    CSIR Research Space (South Africa)

    Meth-Cohn, O

    1994-06-07

    Full Text Available Alpha beta-Epoxy ketones on treatment with baker's yeast yield different types of products depending on their substitution. Small groups such as H or Me attached at the epoxy end protect that end from attack. Thus, 1-acyl epoxides with H, methyl...

  8. Enzymatic epoxidation of biodiesel optimized by response surface ...

    African Journals Online (AJOL)

    During the enzymatic epoxidation of biodiesel, stearic acid was selected as oxygen carrier. Enzyme screening and the load of stearic acid were investigated. The effects of four main reaction conditions including reaction time, temperature, enzyme load, and mole ratio of H2O2/C=C-bonds on the epoxy oxygen group content ...

  9. Effects of experimental variables on the degree of epoxidation of ...

    African Journals Online (AJOL)

    Results show that the acid treatment of the bentonite clay improved its support characteristics by achieving some increase in surface area and optimum treatment condition was found to be 10g bentonite clay treated with 30cm3 sulphuric acid for 6 hours. It was found that higher epoxidation was achieved with treated ...

  10. Properties of epoxide hydrolase from the yeast Rhodotorula glutinis

    NARCIS (Netherlands)

    Ariës-Kronenburg, N.A.E.

    2002-01-01

    Epoxide hydrolases are ubiquitous enzymes that can be found in nearly all living organisms. Some of the enzymes play an important role in detoxifying xenobiotic and metabolic compounds. Others are important in the growth of organisms like

  11. Epoxidation and oxidation reactions using 1,4-butanediol ...

    Indian Academy of Sciences (India)

    Unknown

    and aryl halides to hydroxy compounds through a .... Epoxidation of olefins using 1,4-BDDMA-crosslinked polystyrene supported t- butyl hydroperoxide. Reaction. Isolated. Olefina timeb (h). Productc yield (%). Cinnamic acid. 39 ... aCinnamic acid; bcyclohexene; csubstrate to resin 1 : 2; solvent, dioxan, temperature, 70°C.

  12. Highly efficient epoxidation of alkenes with m-chloroperbenzoic acid ...

    Indian Academy of Sciences (India)

    on a solid support such as polymer, zeolite and silica have recently been reported as innovation in the cat- alytic properties of such compounds.19 23 ..... the homogeneous phases, the Co(III) complex was used ..... solvent-extraction and catalase-like activity studies J. ... 15 as highly active catalysts for epoxidation of styrene.

  13. Propene epoxidation over Au/Ti-SBA-15 catalysts

    NARCIS (Netherlands)

    Sacaliuc, E.; Beale, A.M.; Weckhuysen, B.M.; Nijhuis, T.A.

    2007-01-01

    Highly dispersed gold nanoparticles were synthesized within the channels of a mesoporous Ti-SBA-15 support, followed by thorough catalyst characterization and testing in the selective epoxidation of propene to propene oxide. For this purpose, two series of Ti-SBA-15 materials differing in their Ti

  14. Synthesis of Dinaphtho-dioxaphosphocin-8-oxides, Epoxides and ...

    African Journals Online (AJOL)

    South African Journal of Chemistry ... Preparation of 8-substituted-16H-dinaphtho [2,1-d:1',2'-g] [1,3,2] dioxaphosphocin 8-oxides (5a–g) with an eight-membered phosphorus heterocyclic system (2) and their epoxides and bisphosphonates ... Some of these compounds are found to possess moderate antimicrobial activity.

  15. Synthesis of aluminum nanoparticles capped with copolymerizable epoxides

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Brandon J. [Saint Louis University, Department of Chemistry (United States); Bunker, Christopher E. [Air Force Research Laboratory, Wright-Patterson Air Force Base, Propulsion Directorate (United States); Guliants, Elena A. [University of Dayton Research Institute, Department of Electrical and Computer Engineering (United States); Hayes, Sophia E. [Washington University, Department of Chemistry (United States); Kheyfets, Arthur [Saint Louis University, Department of Chemistry (United States); Wentz, Katherine M. [Washington University, Department of Chemistry (United States); Buckner, Steven W., E-mail: buckners@slu.edu; Jelliss, Paul A., E-mail: jellissp@slu.edu [Saint Louis University, Department of Chemistry (United States)

    2013-06-15

    We report on the synthesis of air-stable aluminum nanoparticles (Al NPs) capped with 1,2-epoxy-9-decene. Long-chain epoxides have proven to be effective capping agents for Al NPs as the epoxide ring is highly susceptible to ring-opening polymerization, leading to the formation of putative polyether loops on the nascent Al NP surface. However, these materials are observed to degrade within several hours to days following exposure to ambient air. By inducing polymerization of the additional terminal alkene functionality on the epoxide, we have produced Al NPs that exhibit both a shelf life of {approx}6 weeks and a high active Al content. Transmission electron microscopy confirms that these spherical nanostructures, {approx}25 nm in diameter, are embedded in a covalently bound polymer matrix that serves as a prophylactic barrier against water/air (H{sub 2}O/O{sub 2}) degradation, and {sup 27}Al solid-state NMR is used to nondestructively confirm the presence of both metallic Al{sup 0} and oxidized Al{sup 3+}. In addition, we have induced polymerization of the epoxide terminal alkene functionality with a long-chain diene monomer, 1,13-tetradecadiene, leading to the formation of Al NPs protected by an extremely hydrophobic polymer matrix. These core-shell nanomaterials also have high active Al contents along with extremely long shelf lives (up to 6 months upon air exposure).

  16. Epoxidation of bulky organic molecules over pillared titanosilicates

    Czech Academy of Sciences Publication Activity Database

    Přech, Jan; Eliášová, Pavla; Aldhayan, D.; Kubů, Martin

    2015-01-01

    Roč. 243, APR 2014 (2015), s. 134-140 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : Cyclooctene * Epoxidation * Layered TS-1 zeolite Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.312, year: 2015

  17. New mechanistic insight in the gold-based propene epoxidation

    NARCIS (Netherlands)

    Parvulescu, E.

    2009-01-01

    Propene oxide is a very important intermediate for the synthesis of commercial products, including adhesives, paints, and cosmetics. The gas-phase epoxidation of propene over Au/Ti-based catalysts is an intriguing scientific topic, not only because of the industrial importance of the production of

  18. Effect of epoxidation level on thermal properties and ionic conductivity of epoxidized natural rubber solid polymer nanocomposite electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Harun, Fatin; Chan, Chin Han; Winie, Tan [Faculty of Applied Sciences, UniversitiTeknologi MARA (UiTM), Shah Alam, 40450 Selangor Darul Ehsan (Malaysia); Sim, Lai Har; Zainal, Nurul Fatahah Asyqin [Center of Foundation Studies, PuncakAlam Campus, UniversitiTeknologi MARA, 40430 Selangor Darul Ehsan (Malaysia)

    2015-08-28

    Effect of epoxide content on the thermal and conductivity properties of epoxidized natural rubber (ENR) solid polymer nanocomposite electrolytes was investigated. Commercial available epoxidized natural rubber having 25 (ENR25) and 50 mole% (ENR50) epoxide, respectively were incorporated with lithium perchlorate (LiClO{sub 4}) salt and titanium dioxide (TiO{sub 2}) nanofiller via solution casting method. The solid polymer nanocomposite electrolytes were characterized by differential scanning calorimetry (DSC) and impedance spectroscopy (IS) for their thermal properties and conductivity, respectively. It was evident that introduction of LiClO{sub 4} causes a greater increase in glass transition temperature (T{sub g}) and ionic conductivity of ENR50 as compared to ENR25. Upon addition of TiO{sub 2} in ENR/LiClO{sub 4} system, a remarkable T{sub g} elevation was observed for both ENRs where ENR50 reveals a more pronounced changes. It is interesting to note that they exhibit different phenomenon in ionic conductivity with TiO{sub 2} loading where ENR25 shows enhancement of conductivity while ENR50 shows declination.

  19. Preparation and biological characteristics of 99mTc-diol a renal agent

    International Nuclear Information System (INIS)

    Castanheira, I.; Paulo, A.; Neves, M.; Patricio, L.; Sawas-Dimopoulou, C.

    1993-01-01

    The present work concerns the production of 1,2-dihydroxypropyl-1-phosphonic acid (diol) by acid hydrolysis of (-cis) 1,2-epoxypropylphosphonic acid (phosphomycin), and its formation as a kit easily labeled with [ 99m Tc]pertechnetate. Biodistribution studies and whole-body autoradiographies in mice show that 99m Tc-diol has a specific affinity for the kidneys: it is rapidly cleared from the blood and excreted in urine. Part of the injected activity remains in the kidney cortex sufficiently long to permit kidney imaging. In comparison with other agents which also localize in the kidney cortex, such as 99m Tc-DMSA and 99m Tc-glucoheptonate ( 99m Tc-GHA), the main differences are the following: the peak of renal activity is reached early in the 5 min post-injection period for 99m Tc-diol, only at about 10 min post-injection for 99m Tc-GHA and after 3 h post-injection for 99m Tc-DMSA. The uptake of 99m Tc-diol by other organs, especially by bones, is much smaller than in the case of 99m Tc-DMSA. Unlike 99m Tc-DMSA, the biodistribution of 99m Tc-diol is not significantly influenced by acid-base imbalance. Moreover, the retention effect of hyperuricemia on 99m Tc-diol blood clearance and kidney excretion could be the result of a competition mechanism between this radiopharmaceutical and uric acid for a common transport system. The above biological characteristics suggest that 99m Tc-diol is a kidney radiopharmaceutical with an ability for functional and imaging studies. (author)

  20. Persistence of urinary excretion products of benzo(a)pyrene

    International Nuclear Information System (INIS)

    Uziel, M.; Haglund, R.; White, D.A.

    1988-01-01

    Persistence of DNA-adducts has been observed in a variety of experimental circumstances and has been suggested as one potential mechanism for explaining the long-term delay before expression of proliferative disease. In this concept, a stable DNA-adduct, which is a remnant of a prior exposure in a nondividing cell, would not express the genotoxic effect until the cells were stimulated to divide, and thus explain the long-term delay in expression of cancer. An alternative view of the observation of persistent DNA-adducts, described in this communication, is the continuing replenishment of DNA adducts by formation and turnover of these adducts from exposure to a constant supply of the ultimate carcinogenic species derived from a prior exposure. It is of interest to note that virtually all experiments where ''persistent'' adducts have been observed have been high dose exposures. During the course of experiments designed to develop improved methods for detection of DNA adducts and related derivatives derived from polynuclear aromatic hydrocarbons (PAH), we observed that there was a continuous excretion of urinary derivatives of the injected benzo(a)pyrene (BaP) beyond the initial burst of detoxification. This report describes the time dependent distribution of those derivatives in blood, urine, feces, and at the site of injection. 11 refs., 5 figs., 4 tabs

  1. Compartmental analysis of benzo[a]pyrene toxicokinetics

    International Nuclear Information System (INIS)

    Bevan, D.R.; Weyand, E.H.

    1986-01-01

    A multicompartmental model to describe quantitatively the toxicokinetics of benzo[a]pyrene (B[a]P) was developed using SAAM (Simulation, Analysis and Modeling). [ 3 H]-B[a]P dissolved in triethylene glycol was administered intratracheally to male Sprague-Dawley rats, and amounts of [ 3 H] were quantified in various tissues at selected times up to 6 hr after administration. Elimination of [ 3 H]-B[a]P and/or metabolites from lungs was biphasic, with half-times of 5.3 min. and 116 min. [ 3 H]-B[a]P and/or metabolites were subsequently distributed primarily to liver and carcass (muscle, bones, fat, skin and associated blood). Carcass contained about 20% of administered [ 3 H] at 6 hr after administration, and agreement between the model and experimental data required that the carcass be modeled as two compartments, one with rapid and one with slow exchange. Approximately 50% of the administered dose was excreted in feces in 6 hr and only 2% appeared in urine. Enterohepatic circulation was accounted for in the model. The model was then used to predict amounts of [ 3 H]-B[a]P and/or metabolites which would be excreted into bile in animals with bile duct cannulas, and good agreement between the model and data was observed

  2. Species differences in biliary excretion of benzo[a]pyrene

    International Nuclear Information System (INIS)

    Weyand, E.H.; Bevan, D.R.

    1986-01-01

    Biliary excretion of benzo[a]pyrene (B[a]P) was investigated in rats, hamsters, and guinea pigs following intratracheal administration. [ 3 H]-B[a]P, in amounts of approximately 150 ng or 350 μg, was instilled into lungs and amounts of radioactivity excreted in bile were monitored for six hrs following administration. Differences in biliary excretion of [ 3 H]-B[a]P and/or metabolites among species were observed at low doses but not at high doses. Six hours after instillation of a low dose of B[a]P, 70, 54, and 62% of the dose was excreted in bile of rats, hamsters, and guinea pigs, respectively. Upon administration of the higher dose of B[a]P, approximately 50% of the dose was excreted in bile in six hrs by all species. Thus, rats and guinea pigs exhibit differences in biliary excretion of low and high doses of B[a]P whereas hamsters do not. Profiles of phase II metabolites in rats and hamsters were similar at both low and high doses, with the majority of metabolites being glucuronides and thioether conjugates. However, differences in relative amounts of these conjugates were observed between the two doses, with a shift towards a greater proportion of glucuronides at the higher dose. Metabolites in bile from guinea pigs were primarily thioether conjugates, which accounted for 88% of metabolites at the low dose and 95% at the high dose

  3. Covalent binding of benzo(a)pyrene-diol-epoxide to histone H2A in rat liver nuclei: target site specificity

    International Nuclear Information System (INIS)

    Kurokawa, M.; MacLeod, M.C.

    1986-01-01

    The authors have recently found that 7r,8t-dihydroxy-9t,10t-oxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE-I), a strong carcinogen, binds selectively to histone H2A-2 variant in rat liver nuclei, using a high performance liquid chromatography (HPLC) system which can separate H4, H2B, 3 different fractions of H2A variants and 3 different H3 variants in an hour. Here the authors examined the binding site of BPDE-I to the H2A-2 variant. The H2A-2 variants were purified from the acid extracted core histones of rat liver nuclei treated with ( 3 H)-BPDE-I by the HPLC system with a semi-preparative Aquapore RP-300 column. HPLC analysis of cyanogen bromide treated-H2A-2, which has one methionine residue, showed that the binding site is located in C-terminal half of H2A-2. In addition, digestions with V8-protease, trypsin and different types of carboxypeptides suggested that there are some target amino acid residues for BPDE-I in the V8-proteolytic C-terminal octapeptide which contains 2 histadine and 3 lysine residues. Currently identification of the target amino acid is proceeding, using amino acid-BPDE adducts prepared in vitro

  4. Ovarian expressed microsomal epoxide hydrolase: Role in detoxification of 4-vinylcyclohexene diepoxide and regulation by phosphatidylinositol-3 kinase signaling

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Poulomi, E-mail: poulomib@iastate.edu [Department of Animal Science, Iowa State University, Ames, IA 50011 (United States); Sen, Nivedita, E-mail: nsen@email.arizona.edu [Department of Physiology, University of Arizona, Tucson, AZ 85724 (United States); Hoyer, Patricia B., E-mail: Hoyer@u.arizona.edu [Department of Physiology, University of Arizona, Tucson, AZ 85724 (United States); Keating, Aileen F., E-mail: akeating@iastate.edu [Department of Animal Science, Iowa State University, Ames, IA 50011 (United States)

    2012-01-01

    4-vinylcyclohexene diepoxide (VCD) is a metabolite of 4-vinylcyclohexene (VCH) which has the potential to be formed in the ovary through CYP2E1 activity. VCD specifically destroys primordial and small primary follicles in the rodent ovary. Mouse ovaries exposed to VCD demonstrate increased mRNA and protein expression of microsomal epoxide hydrolase (mEH), and an inactive tetrol metabolite (4-(1,2-dihydroxy)ethyl-1,2-dihydroxycyclohexane) can be formed in mouse ovarian follicles, potentially through detoxification action of mEH. In contrast, mEH can bioactivate another ovotoxic chemical, 7,12-dimethylbenz[a]anthracene (DMBA) to a more toxic compound, DMBA-3,4-diol-1,2-epoxide. Thus, the present study evaluated a functional role for mEH during detoxification of VCD. Additionally, because inhibition of the phosphatidyinositol-3 kinase (PI3K) signaling pathway in a previous study protected primordial follicles from VCD-induced destruction, but accelerated DMBA-induced ovotoxicity, a role for PI3K in ovarian mEH regulation was evaluated. Using a post-natal day (PND) 4 Fischer 344 rat whole ovary culture system inhibition of mEH using cyclohexene oxide during VCD exposure resulted in a greater (P < 0.05) loss of primordial and small primary follicles relative to VCD-treated ovaries. Also, relative to controls, meh mRNA was increased (P < 0.05) on day 4 of VCD (30 μM) exposure, followed by increased (P < 0.05) mEH protein after 6 days. Furthermore, inhibition of PI3K signaling increased mEH mRNA and protein expression. Thus, these results support a functional role for mEH in the rat ovary, and demonstrate the involvement of PI3K signaling in regulation of ovarian xenobiotic metabolism by mEH. -- Highlights: ► Ovarian mEH functions to metabolize VCD to a less toxic compound. ► mEH expression is increased in a temporal pattern in response to VCD exposure. ► PI3K signaling is involved in regulation of ovarian mEH expression.

  5. Hepatitis B spliced protein (HBSP) promotes the carcinogenic effects of benzo [alpha] pyrene by interacting with microsomal epoxide hydrolase and enhancing its hydrolysis activity

    International Nuclear Information System (INIS)

    Chen, Jin-Yan; Chen, Wan-Nan; Jiao, Bo-Yan; Lin, Wan-Song; Wu, Yun-Li; Liu, Ling-Ling; Lin, Xu

    2014-01-01

    The risk of hepatocellular carcinoma (HCC) increases in chronic hepatitis B surface antigen (HBsAg) carriers who often have concomitant increase in the levels of benzo[alpha]pyrene-7,8-diol-9,10-epoxide(±) (BPDE)-DNA adduct in liver tissues, suggesting a possible co-carcinogenesis of Hepatitis B virus (HBV) and benzo[alpha]pyrene in HCC; however the exact mechanisms involved are unclear. The interaction between hepatitis B spliced protein (HBSP) and microsomal epoxide hydrolase (mEH) was confirmed using GST pull-down, co-immunoprecipitation and mammalian two-hybrid assay; the effects of HBSP on mEH-mediated B[alpha]P metabolism was examined by high performance liquid chromatography (HPLC); and the influences of HBSP on B[alpha]P carcinogenicity were evaluated by bromodeoxyuridine cell proliferation, anchorage-independent growth and tumor xenograft. HBSP could interact with mEH in vitro and in vivo, and this interaction was mediated by the N terminal 47 amino acid residues of HBSP. HBSP could greatly enhance the hydrolysis activity of mEH in cell-free mouse liver microsomes, thus accelerating the metabolism of benzo[alpha]pyrene to produce more ultimate carcinnogen, BPDE, and this effect of HBSP requires the intact HBSP molecule. Expression of HBSP significantly increased the formation of BPDE-DNA adduct in benzo[alpha]pyrene-treated Huh-7 hepatoma cells, and this enhancement was blocked by knockdown of mEH. HBSP could enhance the cell proliferation, accelerate the G1/S transition, and promote cell transformation and tumorigenesis of B[alpha]P-treated Huh-7 hepatoma cells. Our results demonstrated that HBSP could promote carcinogenic effects of B[alpha]P by interacting with mEH and enhancing its hydrolysis activity

  6. The use of positron annihilation to study polyacrylamide and polymethylmethacrylate-Alcohols and diols mixture

    International Nuclear Information System (INIS)

    Mostafa, N.

    2007-01-01

    The effect of addition of both alcohols and diols to polyacrylamide (PAA) and polymethylmethacrylate (PMMA) forming polymer mixtures was studied using positron annihilation lifetime (PAL) and Doppler broadening of annihilation radiation (DBAR) techniques. It was found that, by increasing chain length of alcohols, PAA-alcohols contain free volume with small size V and low fraction f, while PMMA-alcohols contain free volume with large size and high fraction. On the other hand, S-parameter increases and W-parameter decreases in PAA-diols according to the number of carbon and hydrogen atoms in the chain. In addition, the electrical conductivity measurements are performed on the above two polymer mixtures. The results showed that both PAA and PMMA exhibit semiconducting properties by the addition of alcohols and diols. Correlation between the macroscopic conductivity properties and the microstructures such as free volume and microdefects are established

  7. Energy and chemicals from the selective electrooxidation of renewable diols by organometallic fuel cells.

    Science.gov (United States)

    Bellini, Marco; Bevilacqua, Manuela; Filippi, Jonathan; Lavacchi, Alessandro; Marchionni, Andrea; Miller, Hamish A; Oberhauser, Werner; Vizza, Francesco; Annen, Samuel P; Grützmacher, H

    2014-09-01

    Organometallic fuel cells catalyze the selective electrooxidation of renewable diols, simultaneously providing high power densities and chemicals of industrial importance. It is shown that the unique organometallic complex [Rh(OTf)(trop2NH)(PPh3)] employed as molecular active site in an anode of an OMFC selectively oxidizes a number of renewable diols, such as ethylene glycol , 1,2-propanediol (1,2-P), 1,3-propanediol (1,3-P), and 1,4-butanediol (1,4-B) to their corresponding mono-carboxylates. The electrochemical performance of this molecular catalyst is discussed, with the aim to achieve cogeneration of electricity and valuable chemicals in a highly selective electrooxidation from diol precursors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Gas-phase water-mediated equilibrium between methylglyoxal and its geminal diol

    Science.gov (United States)

    Axson, Jessica L.; Takahashi, Kaito; De Haan, David O.; Vaida, Veronica

    2010-01-01

    In aqueous solution, aldehydes, and to a lesser extent ketones, hydrate to form geminal diols. We investigate the hydration of methylglyoxal (MG) in the gas phase, a process not previously considered to occur in water-restricted environments. In this study, we spectroscopically identified methylglyoxal diol (MGD) and obtained the gas-phase partial pressures of MG and MGD. These results, in conjunction with the relative humidity, were used to obtain the equilibrium constant, KP, for the water-mediated hydration of MG in the gas phase. The Gibbs free energy for this process, ΔG°, obtained as a result, suggests a larger than expected gas-phase diol concentration. This may have significant implications for understanding the role of organics in atmospheric chemistry. PMID:20142510

  9. Evaluation of fish models of soluble epoxide hydrolase inhibition.

    OpenAIRE

    Newman, J W; Denton, D L; Morisseau, C; Koger, C S; Wheelock, C E; Hinton, D E; Hammock, B D

    2001-01-01

    Substituted ureas and carbamates are mechanistic inhibitors of the soluble epoxide hydrolase (sEH). We screened a set of chemicals containing these functionalities in larval fathead minnow (Pimphales promelas) and embryo/larval golden medaka (Oryzias latipes) models to evaluate the utility of these systems for investigating sEH inhibition in vivo. Both fathead minnow and medaka sEHs were functionally similar to the tested mammalian orthologs (murine and human) with respect to substrate hydrol...

  10. A New Mn–Salen Micellar Nanoreactor for Enantioselective Epoxidation of Alkenes in Water

    Directory of Open Access Journals (Sweden)

    Francesco P. Ballistreri

    2018-03-01

    Full Text Available A new chiral Mn–salen catalyst, functionalized with a long aliphatic chain and a choline group, able to act as surfactant catalyst for green epoxidation in water, is here described. This catalyst was employed with a commercial surfactant (CTABr leading to a nanoreactor for the enantioselective epoxidation of some selected alkenes in water, using NaClO as oxidant. This is the first example of a nanoreactor for enantioselective epoxidation of non-functionalized alkenes in water.

  11. Markedly Elevated Carbamazepine-10,11-epoxide/Carbamazepine Ratio in a Fatal Carbamazepine Ingestion

    Directory of Open Access Journals (Sweden)

    Jason L. Russell

    2015-01-01

    Full Text Available Carbamazepine is a widely used anticonvulsant. Its metabolite, carbamazepine-10,11-epoxide, has been found to display similar anticonvulsant and neurotoxic properties. While the ratio of parent to metabolite concentration varies significantly, at therapeutic doses the epoxide concentration is generally about 20% of the parent. We report a case of fatal carbamazepine overdose in which the epoxide metabolite concentration was found to be 450% higher than the parent compound, suggesting a potential role for metabolite quantification in severe toxicity.

  12. Lysophosphatidic acids are new substrates for the phosphatase domain of soluble epoxide hydrolase[S

    OpenAIRE

    Oguro, Ami; Imaoka, Susumu

    2012-01-01

    Soluble epoxide hydrolase (sEH) is a bifunctional enzyme that has a C-terminus epoxide hydrolase domain and an N-terminus phosphatase domain. The endogenous substrates of epoxide hydrolase are known to be epoxyeicosatrienoic acids, but the endogenous substrates of the phosphatase activity are not well understood. In this study, to explore the substrates of sEH, we investigated the inhibition of the phosphatase activity of sEH toward 4-methylumbelliferyl phosphate by using lecithin and its hyd...

  13. Thermoresponsive Polymers and Inverse Opal Hydrogels for the Detection of Diols.

    Science.gov (United States)

    Couturier, Jean-Philippe; Wischerhoff, Erik; Bernin, Robert; Hettrich, Cornelia; Koetz, Joachim; Sütterlin, Martin; Tiersch, Brigitte; Laschewsky, André

    2016-05-03

    Responsive inverse opal hydrogels functionalized by boroxole moieties were synthesized and explored as sensor platforms for various low molar mass as well as polymeric diols and polyols, including saccharides, glycopolymers and catechols, by exploiting the diol induced modulation of their structural color. The underlying thermoresponsive water-soluble copolymers and hydrogels exhibit a coil-to-globule or volume phase transition, respectively, of the LCST-type. They were prepared from oligoethylene oxide methacrylate (macro)monomers and functionalized via copolymerization to bear benzoboroxole moieties. The resulting copolymers represent weak polyacids, which can bind specifically to diols within an appropriate pH window. Due to the resulting modulation of the overall hydrophilicity of the systems and the consequent shift of their phase transition temperature, the usefulness of such systems for indicating the presence of catechols, saccharides, and glycopolymers was studied, exploiting the diol/polyol induced shifts of the soluble polymers' cloud point, or the induced changes of the hydrogels' swelling. In particular, the increased acidity of benzoboroxoles compared to standard phenylboronic acids allowed performing the studies in PBS buffer (phosphate buffered saline) at the physiologically relevant pH of 7.4. The inverse opals constructed of these thermo- and analyte-responsive hydrogels enabled following the binding of specific diols by the induced shift of the optical stop band. Their highly porous structure enabled the facile and specific optical detection of not only low molar mass but also of high molar mass diol/polyol analytes such as glycopolymers. Accordingly, such thermoresponsive inverse opal systems functionalized with recognition units represent attractive and promising platforms for the facile sensing of even rather big analytes by simple optical means, or even by the bare eye.

  14. Sources and proxy potential of long chain alkyl diols in lacustrine environments

    Science.gov (United States)

    Rampen, Sebastiaan W.; Datema, Mariska; Rodrigo-Gámiz, Marta; Schouten, Stefan; Reichart, Gert-Jan; Sinninghe Damsté, Jaap S.

    2014-11-01

    Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD) composition of cultures of ten eustigmatophyte species, with three species from different families grown at various temperatures, to identify the effect of species composition and growth temperature on the LCD distribution. The results were compared with the LCD distribution of sixty-two lake surface sediments, and with previously reported LCD distributions from marine environments. The different families within the Eustigmatophyceae show distinct LCD patterns, with the freshwater family Eustigmataceae most closely resembling LCD distributions in both marine and lake environments. Unlike the other two eustigmatophyte families analyzed (Monodopsidaceae and Goniochloridaceae), C28 and C30 1,13-alkyl diols and C30 and C32 1,15-alkyl diols are all relatively abundant in the family Eustigmataceae, while the mono-unsaturated C32 1,15-alkyl diol was below detection limit. In contrast to the marine environment, LCD distributions in lakes did not show a clear relationship with temperature. The Long chain Diol Index (LDI), a proxy previously proposed for sea surface temperature reconstruction, showed a relatively weak correlation (R2 = 0.33) with mean annual air temperature used as an approximation for annual mean surface temperature of the lakes. A much-improved correlation (R2 = 0.74, p-value cultures of the family Eustigmataceae, suggesting that algae belonging to this family have an important role as a source for LCDs in lacustrine environments, or, alternatively, that the main sources of LCDs are similarly affected by temperature as the Eustigmataceae. The results suggest that LCDs may have the potential to be applicable as a palaeotemperature proxy for lacustrine environments

  15. Anti-1,2-Diols via Ni-Catalyzed Reductive Coupling of Alkynes and α-Oxyaldehydes

    Science.gov (United States)

    Luanphaisarnnont, Torsak; Ndubaku, Chudi O.; Jamison, Timothy F.

    2008-01-01

    Ni-catalyzed reductive coupling of aryl alkynes (1) and enantiomerically enriched α-oxyaldehydes (2) afford differentiated anti-1,2-diols (3) with high diastereoselectivity and regioselectivity, despite the fact that the methoxymethyl (MOM) and para-methoxybenzyl (PMB) protective groups typically favor syn-1,2-diol formation in carbonyl addition reactions of this family of aldehydes. PMID:15987174

  16. Regioselective Benzoylation of Diols and Carbohydrates by Catalytic Amounts of Organobase.

    Science.gov (United States)

    Lu, Yuchao; Hou, Chenxi; Ren, Jingli; Xin, Xiaoting; Xu, Hengfu; Pei, Yuxin; Dong, Hai; Pei, Zhichao

    2016-05-17

    A novel metal-free organobase-catalyzed regioselective benzoylation of diols and carbohydrates has been developed. Treatment of diol and carbohydrate substrates with 1.1 equiv. of 1-benzoylimidazole and 0.2 equiv. of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in MeCN under mild conditions resulted in highly regioselective benzoylation for the primary hydroxyl group. Importantly, compared to most commonly used protecting bulky groups for primary hydroxyl groups, the benzoyl protective group offers a new protection strategy.

  17. Iridium‐Catalyzed Condensation of Amines and Vicinal Diols to Substituted Piperazines

    DEFF Research Database (Denmark)

    Lorentz-Petersen, Linda Luise Reeh; Nordstrøm, Lars Ulrik Rubæk; Madsen, Robert

    2012-01-01

    is believed to involve dehydrogenation of the 1,2‐diol to the α‐hydroxy aldehyde, which condenses with the amine to form the α‐hydroxy imine. The latter rearranges to the corresponding α‐amino carbonyl compound, which then reacts with another amine followed by reduction of the resulting imine.......A straightforward procedure is described for the synthesis of piperazines from amines and 1,2‐diols. The heterocyclization is catalyzed by [Cp*IrCl2]2 and sodium hydrogen carbonate and can be achieved with either toluene or water as solvent. The transformation does not require any stoichiometric...

  18. Preliminary studies of epoxidized palm oil as sizing chemical for carbon fibers

    International Nuclear Information System (INIS)

    Salleh, S.N.M.; Ubaidillah, E.A.E.; Abidin, M.F.Z.

    2010-01-01

    Epoxidized palm oil is derived from palm oil through chemical reaction with peracetic acid. Preliminary studies to coat carbon fibers have shown promising result towards applying natural product in carbon fibre composites. Mechanical studies of sized carbon fibers with epoxidized palm oil showed significant increase in tensile and interfacial shear strength. Surface morphology of sized or coated carbon fibers with epoxidized palm oil reveals clear increase in root means square-roughness (RMS). This indicates the change of the surface topography due to sized or coated carbon fibers with epoxidized palm oil. (author)

  19. Epoxide hydrolase-lasalocid a structure provides mechanistic insight into polyether natural product biosynthesis.

    Science.gov (United States)

    Wong, Fong T; Hotta, Kinya; Chen, Xi; Fang, Minyi; Watanabe, Kenji; Kim, Chu-Young

    2015-01-14

    Biosynthesis of some polyether natural products involves a kinetically disfavored epoxide-opening cyclic ether formation, a reaction termed anti-Baldwin cyclization. One such example is the biosynthesis of lasalocid A, an ionophore antibiotic polyether. During lasalocid A biosynthesis, an epoxide hydrolase, Lsd19, converts the bisepoxy polyketide intermediate into the tetrahydrofuranyl-tetrahydropyran product. We report the crystal structure of Lsd19 in complex with lasalocid A. The structure unambiguously shows that the C-terminal domain of Lsd19 catalyzes the intriguing anti-Baldwin cyclization. We propose a general mechanism for epoxide selection by ionophore polyether epoxide hydrolases.

  20. Kinetics of phosphotungstic acid catalyzed oxidation of propan-1,3-diol and butan-1,4-diol by N-chlorosaccharin

    Directory of Open Access Journals (Sweden)

    Sanjay Kumar Singh

    2011-09-01

    Full Text Available The kinetic studies of N-chlorosaccharin (NCSA oxidation of propan-1,3-diol and butan-1,4-diol have been reported in presence of phophotungstic acid and in aqueous acetic acid medium. The reactions follow first-order in NCSA and one to zero order with respect to substrate and phosphotungstic acid. Increase in the concentration of added perchloric acid increases the rate of oxidation. A negative effect on the oxidation rate is observed for solvent whereas the ionic strength does not influence the rate of reaction. Addition of the reaction product, saccharin, exhibited retarding effect. Various activation parameters have been evaluated. The products of the reactions were identified as the corresponding aldehydes. A suitable scheme of mechanism consistent with the experimental results has been proposed.

  1. Topological, functional, and dynamic properties of the protein interaction networks rewired by benzo(a)pyrene

    International Nuclear Information System (INIS)

    Ba, Qian; Li, Junyang; Huang, Chao; Li, Jingquan; Chu, Ruiai; Wu, Yongning; Wang, Hui

    2015-01-01

    Benzo(a)pyrene is a common environmental and foodborne pollutant that has been identified as a human carcinogen. Although the carcinogenicity of benzo(a)pyrene has been extensively reported, its precise molecular mechanisms and the influence on system-level protein networks are not well understood. To investigate the system-level influence of benzo(a)pyrene on protein interactions and regulatory networks, a benzo(a)pyrene-rewired protein interaction network was constructed based on 769 key proteins derived from more than 500 literature reports. The protein interaction network rewired by benzo(a)pyrene was a scale-free, highly-connected biological system. Ten modules were identified, and 25 signaling pathways were enriched, most of which belong to the human diseases category, especially cancer and infectious disease. In addition, two lung-specific and two liver-specific pathways were identified. Three pathways were specific in short and medium-term networks (< 48 h), and five pathways were enriched only in the medium-term network (6 h–48 h). Finally, the expression of linker genes in the network was validated by Western blotting. These findings establish the overall, tissue- and time-specific benzo(a)pyrene-rewired protein interaction networks and provide insights into the biological effects and molecular mechanisms of action of benzo(a)pyrene. - Highlights: • Benzo(a)pyrene induced scale-free, highly-connected protein interaction networks. • 25 signaling pathways were enriched through modular analysis. • Tissue- and time-specific pathways were identified

  2. Topological, functional, and dynamic properties of the protein interaction networks rewired by benzo(a)pyrene

    Energy Technology Data Exchange (ETDEWEB)

    Ba, Qian [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Li, Junyang; Huang, Chao [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Li, Jingquan; Chu, Ruiai [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Wu, Yongning, E-mail: wuyongning@cfsa.net.cn [Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Wang, Hui, E-mail: huiwang@sibs.ac.cn [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); School of Life Science and Technology, ShanghaiTech University, Shanghai (China)

    2015-03-01

    Benzo(a)pyrene is a common environmental and foodborne pollutant that has been identified as a human carcinogen. Although the carcinogenicity of benzo(a)pyrene has been extensively reported, its precise molecular mechanisms and the influence on system-level protein networks are not well understood. To investigate the system-level influence of benzo(a)pyrene on protein interactions and regulatory networks, a benzo(a)pyrene-rewired protein interaction network was constructed based on 769 key proteins derived from more than 500 literature reports. The protein interaction network rewired by benzo(a)pyrene was a scale-free, highly-connected biological system. Ten modules were identified, and 25 signaling pathways were enriched, most of which belong to the human diseases category, especially cancer and infectious disease. In addition, two lung-specific and two liver-specific pathways were identified. Three pathways were specific in short and medium-term networks (< 48 h), and five pathways were enriched only in the medium-term network (6 h–48 h). Finally, the expression of linker genes in the network was validated by Western blotting. These findings establish the overall, tissue- and time-specific benzo(a)pyrene-rewired protein interaction networks and provide insights into the biological effects and molecular mechanisms of action of benzo(a)pyrene. - Highlights: • Benzo(a)pyrene induced scale-free, highly-connected protein interaction networks. • 25 signaling pathways were enriched through modular analysis. • Tissue- and time-specific pathways were identified.

  3. Enzymatic monoesterification of symmetric diols: restriction of molecular conformations influences selectivity.

    Science.gov (United States)

    Tomer, Sanjiv O; Soni, Hemant P

    2017-10-31

    We have experimentally demonstrated that by 'locking' the molecular conformation through the introduction of a double or triple bond in the center of a symmetric diol, enzymatic monoesterification can be achieved selectively. The enzyme Candida antarctica lipase B, generally used for the transesterification of diols, can be effectively used for the monoesterification of symmetrical diols in an unbuffered system also. By varying the chain length of a carboxylic acid moiety, we have established that optimum selectivity and efficiency can be achieved in the range of 4.8 to 5.0 pK a values. Selectivity can be improved up to 98.75% for a monoester in an overall 73% yield (mixture of a monoester and a diester) when but-2-yne-1,4-diol reacted with hexanoic acid. Water, a by-product, provides an interfacial environment for the enzyme to work in the organic reaction medium. The uniqueness of the reported monoesterification protocol is that it involves only the mechanical stirring of the reaction mixture at room temperature in the presence of the enzyme for 24 h. High percentage yield with selectivity for a monoester, easier product isolation and overall, environmental sustainability are added advantages. The synthesized monoesters are characterized by using HNMR and high resolution mass spectrometry (HRMS).

  4. Synthesis of enantiomerically pure thiocrown ethers derived from 1,1'-binaphthalene-2,2'-diol

    NARCIS (Netherlands)

    Stock, H. Thijs; Kellogg, Richard M.

    1996-01-01

    Synthetic methodology is given for the preparation of two different types of thiocrown ethers from optically pure 1,1'-binaphthalene-2,2'-diol (10). The conceptually simplest approach starts from optically pure 10 itself, which is alkylated (4 equiv of K2CO3 in DMF at 110 degrees C) with

  5. Thermoplastic poly(urethane urea)s from novel, bio-based amorphous polyester diols

    NARCIS (Netherlands)

    Tang, D.; Noordover, B.A.J.; Sablong, R.J.; Koning, C.E.

    2012-01-01

    In this study, two novel, bio-based, amorphous polyester diols, namely poly(1,2-dimethylethylene adipate) (PDMEA) and poly(1,2-dimethylethylene succinate) (PDMES) are used to prepare thermoplastic poly(urethane urea)s (TPUUs). Interestingly, the TPUUs based on PDMEA show similar thermal and

  6. 211At-Rh(16-S4-diol) complex as a precursor for astatine radiopharmaceuticals

    International Nuclear Information System (INIS)

    Pruszynski, M.; Bilewicz, A.

    2006-01-01

    211 At is one of the most promising radionuclides in α-radioimmunotherapy (α-RIT). Unfortunately, biomolecules labeled by direct electrophilic astatination are unstable due to the rapid loss of 211 At under both in vitro and in vivo conditions. The present paper describes the results of our studies on attaching At - to the rhodium(III) complex with thioether ligand: 1,5,9,13-etrathiacyclohexadecane-3,11-diol (16-S4-diol). Rh 3+ was chosen as a moderately soft metal cation which should form very strong bonds with soft At - anions, but first of all because of the kinetic inertness of low spin rhodium(III) d 6 complexes. The 16-S4-diol ligand was selected due to formation of stable complexes with Rh 3+ . The experiments related to optimization of the reaction conditions were performed with the 131 I, basing on a chemical similarity of I - to At - . The experiments with 211 At were then carried out under the conditions found optimal for I - . The preliminary results are promising, and indicate a possibility for astatination of biomolecules by using the 211 At-Rh(16-S4-diol) complex

  7. Microbial Stereoselective One-Step Conversion of Diols to Chiral Lactones in Yeast Cultures

    Directory of Open Access Journals (Sweden)

    Filip Boratyński

    2015-12-01

    Full Text Available It has been shown that whole cells of different strains of yeast catalyze stereoselective oxidation of meso diols to the corresponding chiral lactones. Among screening-scale experiments, Candida pelliculosa ZP22 was selected as the most effective biocatalyst for the oxidation of monocyclic diols 3a–b with respect to the ratio of high conversion to stereoselectivity. This strain was used in the preparative oxidation, affording enantiomerically-enriched isomers of lactones: (+-(3aR,7aS-cis-hexahydro-1(3H -isobenzofuranone (2a and (+-(3aS,4,7,7aR-cis-tetrahydro-1(3H-isobenzofuranone (2b. Scaling up the culture growth, as well as biotransformation conditions has been successfully accomplished. Among more bulky substrates, bicyclic diol 3d was totally converted into enantiomerically-pure exo-bridged (+-(3aR,4S,7R,7aS-cis-tetrahydro-4,7-methanoisobenzofuran -1(3H-one (2d by Yarrovia lipolytica AR71. Microbial oxidation of diol 3f by Candida sake AM908 and Rhodotorula rubra AM4 afforded optically-pure cis-3-butylhexahydro-1(3H -isobenzofuranone (2f, however with low conversion.

  8. An efficient hydrophilic interaction liquid chromatography separation of 7 phospholipid classes based on a diol column

    NARCIS (Netherlands)

    Zhu, C.; Dane, A.; Spijksma, G.; Wang, M.; Greef, J. van der; Luo, G.; Hankemeier, T.; Vreeken, R.J.

    2012-01-01

    A hydrophilic interaction liquid chromatography (HILIC) - ion trap mass spectrometry method was developed for separation of a wide range of phospholipids. A diol column which is often used with normal phase chromatography was adapted to separate different phospholipid classes in HILIC mode using a

  9. Modification of olefinic double bonds of unsaturated fatty acids and other vegetable oil derivatives via epoxidation: A review

    International Nuclear Information System (INIS)

    Noor Armylisas, A.H.; Siti Hazirah, M.F.; Yeong, S.K.; Hazimah, A.H.

    2017-01-01

    The highly strained ring in epoxides makes these compounds very versatile intermediates. Epoxidized vegetable oils are gaining a lot of attention as renewable and environmentally friendly feedstock with various industrial applications such as plasticizers, lubricant base oils, surfactants, etc. Numerous papers have been published on the development of the epoxidation methods and the number is still growing. This review reports the synthetic approaches and applications of epoxidized vegetable oils. [es

  10. Prenatal induction of benzo(a)pyrene hydroxylases in mice

    International Nuclear Information System (INIS)

    Neubert, D.; Tapken, S.

    1988-01-01

    1. Benzo(a)pyrene hydroxylase (BPH) activity was measured in homogenates of fetal liver (day 18) or of whole-embryos of mice on day 9, 10 or 12 of gestation after maternal pretreatment with B(a)P on 3 consecutive days. A 3 H-liberation assay with 3 H-B(a)P labelled either generally or at the 6-position was used. The values obtained with the embryonic/fetal tissues were compared with those found in maternal liver. 2. Three oral doses of 17.5 mg B(a)P/kg body wt were found to just significantly induce BPH in maternal liver. An induction was observed after pretreatment with 24 mg B(a)P/kg body wt in 9, 10 or 12-day-old whole-embryos, but the V max reached was only 10-20% (1% on day 9) of that of adult non-induced liver. The K m (6-hydroxylation) for all tissues tested were in the same range (600-900 nM). The induction was demonstrable in embryos at tissue levels about one order of magnitude lower than those required for induction in maternal liver. 3. Treatment with 25 mg B(a)P/kg body wt on 3 consecutive days was required to induce BPH in fetal liver on day 18 of gestation. The required B(a)P tissue concentrations were about one half of those necessary for induction in maternal liver. 4. Among a variety of other polycyclic hydrocarbons only chrysene showed an inducing potency similar to that of B(a)P in adult and fetal liver. For all compounds tested there was no correlation found in the inducing potency between adult and fetal liver (e.g. coronene). 5. The doses required to induce BPH in the maternal or fetal liver or in whole embryos of rodents are significantly higher (mg range) than those of usual average human exposure or those taken up by smokers (ng range). (orig.)

  11. Resolution of limonene 1,2-epoxide diastereomers by mercury(II) ions

    NARCIS (Netherlands)

    Werf, M. van der; Jongejan, H.; Franssen, M.C.R.

    2001-01-01

    When HgCl2 was added to a diastereomeric mixture of cis- and trans-(4S)-limonene 1,2-epoxide, the Hg(II) ions stereoselectively complexed to the cis epoxide, enabling ring opening by water. The resulting mercuric salt could be demetalated by treatment with NaBH4, giving a mixture of diastereomeric

  12. Derivatization of castor oil based estolide esters: Preparation of epoxides and cyclic carbonates

    Science.gov (United States)

    Estolides that are based on castor oil and oleic acid are versatile starting points for the production of industrial fluids with new properties. A variety of unsaturated estolides were derivatized by epoxidation with hydrogen peroxide. The epoxidized estolides were further modified using supercritic...

  13. Interaction of model aryl- and alkyl-boronic acids and 1,2-diols in aqueous solution.

    Science.gov (United States)

    Marinaro, William A; Prankerd, Richard; Kinnari, Kaisa; Stella, Valentino J

    2015-04-01

    The goal of this work was to quantitate ester formation between alkyl and aryl boronic acids and vicinal-diols or 1,2-diols in aqueous solution. As used here, 1,2-diols includes polyols with one or more 1,2-diol pairs. Multiple techniques were used including apparent pKa shifts of the boronic acids using UV spectrophotometry (for aryl acids) and titration (for aryl and alkyl acids). Isothermal microcalorimetry was also used, with all reactions being enthalpically favored. For all the acids and 1,2-diols and the conditions studied, evidence only supported 1:1 ester formation. All the esters formed were found to be significantly more acidic, as Lewis acids, by 3-3.5 pKa units than the corresponding nonesterified boronic acid. The equilibrium constants for ester formation increased with increasing number of 1,2-diol pairs but stereochemistry may also play a role as sorbitol with five possible 1,2-diol pairs and five isomers (taking into account the stereochemistry of the alcohol groups) was twice as efficient at ester formation compared with mannitol, also with five possible 1,2-diol pairs but only three isomers. Alkyl boronic acids formed esters to a greater extent than aryl acids. Although some quantitative differences were seen between the various techniques used, rank ordering of the structure/reactivity was consistent. Formulation implications of ester formation between boronic acids and 1,2-diols are discussed. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  14. Effect of epoxide equivalent on microstructure of epoxy/rectorite nanocomposite studied by positrons

    International Nuclear Information System (INIS)

    Liu, L.M.; Fang, P.F.; Zhang, S.P.; Wang, S.J.

    2005-01-01

    The epoxy/rectorite nanocomposites with different epoxide equivalent ranging from 188 to 1110 were prepared and the effects of epoxide equivalent on microstructure of materials were studied by X-ray diffraction (XRD) and positron annihilation lifetime spectroscope (PALS). In nanocomposites, the formation of exfoliated structure was observed from XRD pattern at epoxide equivalent >263. The PALS measurements reveal that the fractional free volume in nanocomposites was strongly affected by epoxide equivalent, in particular, the free-volume concentration was dramatically decreased with the increasing epoxide equivalent from 188 to 263, and the S parameter indicates the rectorite structure change and the high sensitivity of positron annihilation to the entry of rectorite into epoxy. These results indicate that positron annihilation characteristics are useful for study the microstructure of epoxy/rectorite nanocomposites

  15. Separation of water-soluble metabolites of benzo[a]pyrene formed by cultured human colon

    DEFF Research Database (Denmark)

    Autrup, Herman

    1979-01-01

    A method has been developed to separate conjugated metabolites of benzo[a]pyrene into three major fractions: sulfate esters, glucuronides and glutathione conjugates. In cultured human colon, formation of sulfate esters and glutathione conjugates is the major conjugation pathway, while formation......-hydroxybenzo[a]pyrene were the major substrates for sulfotransferase in cultured human colon....

  16. Mechanism-based inactivation of benzo[a]pyrene hydroxylase by aryl acetylenes and aryl olefins

    International Nuclear Information System (INIS)

    Gan, L.S.; Lu, J.Y.L.; Alworth, W.L.

    1986-01-01

    A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxgenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, 3-ethynylperylene, 2-ethynylfluorene, methyl 1-pyrenyl acetylene, cis- and trans-1-(2-bromovinyl)pyrene, and 1-allylpyrene serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo[a]pyrene hydroxylase, while 1-vinylpyrene and phenyl 1-pyrenyl acetylene do not cause a detectable suicide inhibition of benzo[a]pyrene hydroxylase. The mechanism-based loss of benzo[a]pyrene hydroxylase caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes (suicide destruction). The suicide inhibition by these aryl acetylenes therefore does not involve covalent binding to the heme moiety of the monooxygenase. Nevertheless, in the presence of NADPH, 3 H-labeled 1-ethynylpyrene becomes covalently attached to the cytochrome P-450 protein; the measured stoichiometry of binding is one 1-ethynylpyrene per P-450 heme unit. The authors conclude that the inhibition of benzo[a]pyrene hydroxylase produced by 1-ethynylpyrene may be related to the mechanism of suicide inhibition of P-450 activity by chloramphenicol rather than the mechanism of suicide destruction of P-450 previously described for acetylene and propyne

  17. Solubility of Benzo[a]pyrene and Organic Matter of Soil in Subcritical Water

    Directory of Open Access Journals (Sweden)

    Svetlana Sushkova

    2015-12-01

    Full Text Available A dynamic subcritical water extraction method of benzo[a]pyrene from soils is under consideration. The optimum conditions for benzo[a]pyrene extraction from soil are described including the soil treatment by subcritical water at 250 °C and 100 atm for 30 min. The effectiveness of developed method was determined using the matrix spiking recovery technique. A comparative analysis was made to evaluate the results of benzo[a]pyrene extraction from soils using the subcritical water and organic solvents. The advantages of the subcritical water extraction involve the use of ecologically friendly solvent, a shorter time for the analysis and a higher amount of benzo[a]pyrene extracted from soil (96 %. The influence of subcritical water extraction on soil properties was measured the investigation of the processes occurring within soil under the influence the high temperature and pressure. Under appropriate conditions of the experiment there is the destruction of the soil organic matter while the composition of the soil mineral fraction remains practically unchanged.

  18. Effect of various chemicals on the metabolism of benzo(a)pyrene by cultured rat colon

    DEFF Research Database (Denmark)

    Autrup, Herman; Harris, Curtis C.; Fugaro, Steven

    1977-01-01

    The effect of various co- and anti-carcinogens of colon carcinogenesis on the metabolism of benzo(a)pyrene (BP) in cultured rat colon is reported. Rat colon enzymatically converted BP into metabolites which bind to cellular macromolecules i.e., DNA and protein. Activity of aryl hydrocarbon...

  19. On the carcinogenic polycyclic aromatic hydrocarbon benzo(a)pyrene in volcano exhausts.

    Science.gov (United States)

    Ilnitsky, A P; Belitsky, G A; Shabad, L M

    1976-05-01

    The content of benzo(a)pyrene in the juvenile ashes of the volcano Tyatya (Kunashir Island, Kuriles) and in the soil, vegetation and volcanic mud collected near volcanos in Kamchatka was studied. It was concluded that volcanic activity does not play a large role in forming the background level of this carcinogen in the human environment.

  20. Investigation of biological destruction of benzo[a]pyrene andpolycyclic aromatic hydrocarbons of biochar in soil

    Science.gov (United States)

    Okunev, R. V.; Smirnova, E. V.; Sharipova, A. R.; Gilmutdinova, I. M.; Giniyatullin, K. G.

    2018-01-01

    The biological decomposition of benzo[a]pyrene in the concentrations exceeding the MAC (maximum permissible concentration) level in soils by 2, 5 and 10 times was studied in laboratory conditions. The gray forest soil samples were contaminated with benzo[a]pyrene and incubated in optimum for bacterial growth soil moisture for 30 and 60 days. The residual amount of contaminant was monitored by HPLC after extraction with acetone-cyclohexane (2:1). Soil microbial activity was evaluated by measuring basal respiration (BR) and substrate-induced respiration (SID) rates of the soil by gas chromatography. The results of the experiment showed that in 60 days the amount of benzo[a]pyrene in contaminated soils decreased; however, this time was not enough for complete decomposition of pollutant. In this case, benzo[a]pyrene has a negative effect on the BR and SIR rates. Soil contamination affected the BR rate only at high doses (10 MPC), whereas the SIR was a more sensitive indicator of the toxic effect of the pollutant and significantly reacts already at concentrations at the level of 2 MPC. The combination of PAHs isolated from biochar has a strong negative effect on the values of BR and SIR.

  1. Epoxidation of polybutadiene rubber in non polar solvent

    International Nuclear Information System (INIS)

    Schneider, Luciane K. de A.; Jacobi, Marly A.M.

    2005-01-01

    The epoxidation of polybutadiene rubber in cyclohexane, at 50 deg C, by the method of performic acid generated in situ, at different reagent concentration was investigated. The epoxy degree was determined by 1 H-RMN, and because of the gelation and coagulation of modified rubber during the reaction, only a maximum of 30 mol % of epoxy degree could be achieved. The reaction followed a first order kinetic in relation to hydrogen peroxide and acid concentration showing a rate constant of 4,0 (± 0,5) x 10 -5 L.mol-1.seg -1 . (author)

  2. Chiral 1,2- and 1,3-diol-functionalized chromophores as Lego building blocks for coupled structures.

    Science.gov (United States)

    Spange, Stefan; Hofmann, Katja; Walfort, Bernhard; Rüffer, Tobias; Lang, Heinrich

    2005-10-14

    Chiral nitroanilines containing 1,2- or 1,3-diol functionalities have been synthesized by nucleophilic aromatic substitution of fluoronitroanilines with 1-aminopropane-2,3-diols and 2-aminopropane-1,3-diol in the melt. X-ray structure analyses confirm retention of the configuration of the chiral center. The novel chromophores are suitable to link reversibly to various substituted arylboronic acids which allows the construction of new solvatochromic sensor molecules suitable to response to solvent and anion coordination by fluoride. The solvatochromism of the new compounds has been studied using the Kamlet-Taft LSE relationship.

  3. Evaluation of the genotoxic potential of 3-monochloropropane-1,2-diol (3-MCPD) and its metabolites, glycidol and beta-chlorolactic acid, using the single cell gel/comet assay.

    Science.gov (United States)

    El Ramy, R; Ould Elhkim, M; Lezmi, S; Poul, J M

    2007-01-01

    3-monochloropropane-1,2-diol (3-MCPD) is a member of a group of chemicals known as chloropropanols. It is found in many foods and food ingredients as a result of food processing. 3-MCPD is regarded as a rat carcinogen known to induce Leydig-cell and mammary gland tumours in males and kidney tumours in both genders. The aim of our study was to clarify the possible involvement of genotoxic mechanisms in 3-MCPD induced carcinogenicity at the target organ level. For that purpose, we evaluated DNA damages in selected target (kidneys and testes) and non-target (blood leukocytes, liver and bone marrow) male rat organs by the in vivo alkaline single cell gel electrophoresis (comet) assay, 3 and 24 h after 3-MCPD oral administration to Sprague-Dawley and Fisher 344 adult rats. 3-MCPD may be metabolised to a genotoxic intermediate, glycidol, whereas the predominant urinary metabolite in rats following 3-MCPD administration is beta-chlorolactic acid. Therefore, we also studied the DNA damaging effects of 3-MCPD and its metabolites, glycidol and beta-chlorolactic acid, in the in vitro comet assay on CHO cells. Our results show the absence of genotoxic potential of 3-MCPD in vivo in the target as well as in the non-target organs. Glycidol, the epoxide metabolite, induced DNA damages in CHO cells. beta-Chlorolactic acid, the main metabolite of 3-MCPD in rats, was shown to be devoid of DNA-damaging effects in vitro in mammalian cells.

  4. 4 Birds 1 Stone to Inhibit 5androstane-3alpha,17beta-diol Conversion to DHT

    Science.gov (United States)

    2016-09-01

    Award Number: W81XWH-15-1-0409 TITLE: 4 Birds 1 Stone to Inhibit 5androstane-3alpha,17beta-diol Conversion to DHT PRINCIPAL INVESTIGATOR...SUBTITLE 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-15-1-04094 Birds 1 Stone to Inhibit 5androstane-3alpha,17beta-diol Conversion to DHT 5c...testicular androgens, testosterone or dihydrotestosterone ( DHT ). Men diagnosed with advanced prostate cancer or failure potentially curative therapy are

  5. Study of epoxidation and its influence on the poly dienes behavior

    International Nuclear Information System (INIS)

    Rocha, Tatiana L.A.C.; Schuster, Robert H.; Meier, Jens; Jacobi, Marly M.; Samios, Dimitrios

    2001-01-01

    The poly dienes epoxidation is a good method to modify the backbone chain, improving some of its properties. The epoxidation rate changes with the time and reaction temperature, epoxidize agent and polymer microstructure. There are two kinds of different kinetic behavior during the reaction of epoxidation, which are related to the epoxidation of trans 1,4 and cis 1,4 double bonds. An increase in the epoxidation content leads to an increase in the glass temperature (Tg) in all materials studied. Tailor-made linear poly dienes modified by epoxidation also show shifts of the flow region of the viscoelastic spectra to lower frequencies and significant changes in the dynamic mechanical storage and loss moduli. With higher side group density, the plateau modulus decreases due to lower entanglement density and the frequency limits of the rubber elastic region shift to lower values. Higher molecular weights shift the onset of the flow region towards lower frequencies extending the rubbery plateau. The predictions of refined tube models, which are derived directly from molecular considerations are in good correlation with the experimental data. (author)

  6. Physio-pharmacological Investigations About the Anti-inflammatory and Antinociceptive Efficacy of (+)-Limonene Epoxide.

    Science.gov (United States)

    de Almeida, Antonia Amanda Cardoso; Silva, Renan Oliveira; Nicolau, Lucas Antonio Duarte; de Brito, Tarcísio Vieira; de Sousa, Damião Pergentino; Barbosa, André Luiz Dos Reis; de Freitas, Rivelilson Mendes; Lopes, Luciano da Silva; Medeiros, Jand-Venes Rolim; Ferreira, Paulo Michel Pinheiro

    2017-04-01

    D-limonene epoxidation generates (+)-limonene epoxide, an understudied compound in the pharmacologically point of view. Herein, we investigated the anti-inflammatory and antinociceptive potentialities of (+)-limonene epoxide and suggested a mechanism of action. The anti-inflammatory potential was analyzed using agents to induce paw edema, permeability, and myeloperoxidase (MPO) activity. Pro-inflammatory cytokines and cell migration of peritoneal cells were also assessed. Antinociceptive effects were evaluated by writhing test induced by acetic acid, formalin, and hot plate assays and contribution of opioid pathways. Pretreated animals with (+)-limonene epoxide showed reduced carrageenan-induced paw edema in all doses (25, 50, and 75 mg/kg) (P Limonene epoxide diminished abdominal contortions induced by acetic acid (78.9%) and paw licking times in both 1 (41.8%) and 2 (51.5%) phases and a pretreatment with naloxone (3 mg/kg) reverted the antinociceptive action in morphine- and (+)-limonene epoxide-treated groups (P limonene epoxide inhibited release/activity of inflammatory mediators, vascular permeability, migration of neutrophils and displayed systemic and peripheral analgesic-dependent effects of the opioid system.

  7. Systemic excretion of benzo(a)pyrene in the control and microsomally induced rat: the influence of plasma lipoproteins and albumin as carrier molecules

    International Nuclear Information System (INIS)

    Shu, H.P.; Bymun, E.N.

    1983-01-01

    In vitro studies have previously indicated that benzo(a)pyrene distributes primarily into the plasma lipoprotein fraction when incubated with whole plasma. Hydroxylated metabolites of benzo(a)pyrene distribute increasingly into the albumin fraction as the degree of metabolite hydroxylation increases. This report assesses the influence of plasma lipoproteins and albumin as carriers for benzo(a)pyrene on carcinogen excretion in the control and microsomally induced rat. Male Sprague-Dawley rats cannulated in the bile duct received i.v. injections of radiolabeled benzo(a)pyrene noncovalently bound to the very-low-density, low-density, or high-density lipoproteins in equimolar amounts. Bile was collected and measured for radioactivity. Cumulative biliary excretions of benzo(a)pyrene complexed with rat lipoproteins were 39.6 +/- 9.7 (S.D.), 24.6 +/- 1.3, and 21.2 +/- 8.8% for very low-density, low-density, and high-density lipoprotein, respectively. Values for excretion of benzo(a)pyrene complexed with rat or human lipoproteins were comparable. These data suggest that the transport molecule can effect a 2-fold difference in benzo(a)pyrene excretion under conditions of the present study. Thus, excretion increased as the degree of benzo(a)pyrene hydroxylation increased. The effect of microsomal enzyme induction on excretion of lipoprotein-bound benzo(a)pyrene was also assessed. Contrary to expectation, excretion of benzo(a)pyrene bound to the very-low-density, low-density, or high-density lipoproteins in Aroclor-induced rats was not greater than that of control animals. Hence, under the conditions of the present study, 60 to 80% of the injected benzo(a)pyrene and 50 to 60% of the injected benzo(a)pyrene metabolites were not excreted immediately in control or microsomally induced animals. This benzo(a)pyrene may represent a carcinogen pool that is slowly excreted

  8. Isomerization of 2-butene-1,4-diol in aqueous solutions catalyzed by palladium(II) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kalabin, S.M.; Novikov, N.A.; Belov, A.P.

    1989-02-01

    The authors studied the isomerization of 2-butene-1,4-diol into 3-butene-1,2-diol at 18-25/degree/C. The concentrations of the diol and PdCl/sub 2/ were (1.0-5.0) /times/ 10/sup /minus/2/ mole/liter at 5-10-fold excess amounts of HCl and NaCl. These additives were used because of their inhibiting action on the oxidation of olefinic compounds. 3-Butene-1,2-diol was identified by /sup 1/H NMR method directly in the reaction solutions in which the reaction solutions in which the reactions in D/sub 2/O were carried out. It was found that palladium(II) complexes catalyze the isomerization of 2-butene-1,4-diol into 3-butene-1,2-diol. A mechanism is proposed for the reaction, which includes the intermediate formation of /eta//sup 3/-allyl complex of palladium with a coordinated hydroxyl group.

  9. Mesogenic polybuthadiene diols with thiol side-chain units: synthesis and thermal behaviour

    Czech Academy of Sciences Publication Activity Database

    Bubnov, Alexej; Kašpar, Miroslav; Sedláková, Zdeňka

    2010-01-01

    Roč. 83, č. 1 (2010), 16-27 ISSN 0141-1594 R&D Projects: GA AV ČR IAA100100911; GA AV ČR(CZ) GA202/09/0047; GA MŠk OC 175 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z40500505 Keywords : mesogenic polymer * phase transition * polybutadiene diol * side -chain polymer Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.006, year: 2010

  10. Crystallization of DNA fragments from water-salt solutions, containing 2-methylpentane-2,3-diol.

    Science.gov (United States)

    Osica, V D; Sukharevsky, B Y; Vasilchenko, V N; Verkin, B I; Polyvtsev, O F

    1976-09-01

    Fragments of calf thymus DNA have been crystallized by precipitation from water-salt solutions, containing 2-methylpentane-2,3-diol (MPD). DNA crystals usually take the form either of spherulites up to 100 mu in diameter or of needles with the length up to 50 mu. No irreversible denaturation of DNA occurs during the crystallization process. X-ray diffraction from dense slurries of DNA crystals yields crystalline powder patterns.

  11. Methods of producing epoxides from alkenes using a two-component catalyst system

    Science.gov (United States)

    Kung, Mayfair C.; Kung, Harold H.; Jiang, Jian

    2013-07-09

    Methods for the epoxidation of alkenes are provided. The methods include the steps of exposing the alkene to a two-component catalyst system in an aqueous solution in the presence of carbon monoxide and molecular oxygen under conditions in which the alkene is epoxidized. The two-component catalyst system comprises a first catalyst that generates peroxides or peroxy intermediates during oxidation of CO with molecular oxygen and a second catalyst that catalyzes the epoxidation of the alkene using the peroxides or peroxy intermediates. A catalyst system composed of particles of suspended gold and titanium silicalite is one example of a suitable two-component catalyst system.

  12. Technological aspects of vegetable oils epoxidation in the presence of ion exchange resins: a review

    Directory of Open Access Journals (Sweden)

    Milchert Eugeniusz

    2016-09-01

    Full Text Available A review paper of the technology basics of vegetable oils epoxidation by means of peracetic or performic acid in the presence of acidic ion exchange resins has been presented. The influence of the following parameters: temperature, molar ratio of acetic acid and hydrogen peroxide to ethylenic unsaturation, catalyst loading, stirring intensity and the reaction time on a conversion of ethylenic unsaturation, the relative percentage conversion to oxirane and the iodine number was discussed. Optimal technological parameters, mechanism of epoxidation by carboxylic peracids and the possibilities of catalyst recycling have been also discussed. This review paper shows the application of epoxidized oils.

  13. Synthesis of Biolubricant Basestocks from Epoxidized Soybean Oil

    Directory of Open Access Journals (Sweden)

    Rosa Turco

    2017-10-01

    Full Text Available This work deals with the preparation of biolubricant basestocks through the ring-opening reaction of epoxidized soybean oil (ESO by alcohols in presence of solid acid catalysts (SAC-13 resin. To this end, different experimental runs were carried out in a lab-scale reactor, analyzing the effect of the alcohol (methanol, ethanol, 2-propanol, 2-butanol, catalyst mass loading (from 1 to 10 wt % with respect to the oil mass and operating temperature (60–90 °C. The main focus of investigation was oxirane conversion. The study was complemented by FT-IR, 1H NMR and kinematic viscosity characterization of the different products of the ring-opening reaction. Experimental conversion data were fitted through a suitable kinetic model. Values of the best-fitting parameters in terms of rate constant, activation energy and catalyst reaction order were obtained, and were potentially useful for the design of an industrial process.

  14. Microwave absorption properties of barium titanate/epoxide resin composites

    International Nuclear Information System (INIS)

    Chen Xiaodong; Wang Guiqin; Duan Yuping; Liu Shunhua

    2007-01-01

    Nano-barium titanate (BT) was prepared by a sol-gel method. The prepared powders were characterized by x-ray powder diffraction and transmission electron microscopy. The complex relative dielectric permittivity (ε = ε' - jε-prime) and magnetic permeability (μ = μ' - jμ-prime) of the BT powders were measured in the frequency range 8 ∼ 18 GHz. The BT/epoxide resin (EP) composite with different volume contents was investigated. The effects of thickness on the BT/EP composite were studied. It was found that an optimum thickness and contents of the absorber can yield the maximum reflection loss which could be obtained over a broad frequency region in the X and Ku bands. Our results indicate that BT could be a promising microwave absorption material

  15. Bacillus subtilis is a Potential Degrader of Pyrene and Benzo[a]pyrene

    Directory of Open Access Journals (Sweden)

    Lynette Ekunwe

    2005-08-01

    Full Text Available Polycyclic Aromatic Hydrocarbons (PAHs are a group of compounds that pose many health threats to human and animal life. They occur in nature as a result of incomplete combustion of organic matter, as well as from many anthropogenic sources including cigarette smoke and automobile exhaust. PAHs have been reported to cause liver damage, red blood cell damage and a variety of cancers. Because of this, methods to reduce the amount of PAHs in the environment are continuously being sought. The purpose of this study was to find soil bacteria capable of degrading high molecular weight PAHs, such as pyrene (Pyr and benzo[a]pyrene (BaP, which contain more than three benzene rings and so persist in the environment. Bacillus subtilis, identified by fatty acid methyl ester (FAME analysis, was isolated from PAH contaminated soil. Because it grew in the presence of 33μg/ml each of pyrene, 1-AP and 1-HP, its biodegradation capabilities were assessed. It was found that after a four-day incubation period at 30oC in 20μg/ml pyrene or benzo[a]pyrene, B. subtilis was able to transform approximately 40% and 50% pyrene and benzo[a]pyrene, respectively. This is the first report implicating B. subtilis in PAH degradation. Whether or not the intermediates resulting from the transformation are more toxic than their parent compounds, and whether B. subtilis is capable of mineralizing pyrene or benzo[a]pyrene to carbon dioxide and water, remains to be evaluated.

  16. Benzo(a)pyrene activation and detoxification by human pulmonary alveolar macrophages and lymphocytes

    International Nuclear Information System (INIS)

    Marshall, M.V.; McLemore, T.L.; Martin, R.R.; Marshall, M.H.; Wray, N.P.; Busbee, D.L.; Cantrell, E.T.; Arnott, M.S.; Griffin, A.C.

    1980-01-01

    Comparisons of pulmonary alveolar macrophages and circulating lymphocytes from five smokers and five nonsmokers for their ability to metabolize benzo(a)pyrene as determined by high pressure liquid chromatography were carried out. Utilizing this approach, further investigation of activation and detoxification by several human cell types could provide the basis for more precise and comprehensive studies of carcinogen and drug metabolism in the human lung, and for a better assessment of cancer risk in selected populations

  17. Approches synthétiques vers le mycothiazole-4,19-diol : utilisation du palladium en synthèse organique

    OpenAIRE

    Batt , Frédéric

    2009-01-01

    Mycothiazole-4,19-diol is a natural compound isolated in 2006 from a marine sponge cacospongia mycofijiensis which has never been synthesized. Its unique structure, its weak abundance and its potential biological activity make mycothiazole-4,19-diol an attractive target in organic chemistry. The challenge is the building of allylic diol-1,2 moiety. In order to make a concise and elegant synthesis of this molecule, four disconnections and many approaches have been studied. A study about the us...

  18. Biobased composites from thermoplastic polyurethane elastomer and cross-linked acrylated-epoxidized soybean oil

    Science.gov (United States)

    Soybean oil is an important sustainable material. Crosslinked acrylated epoxidized soybean oil (AESO) is brittle without flexibility and the incorporation of thermoplastic polyurethane improves its toughness for industrial applications. The hydrophilic functional groups from both oil and polyurethan...

  19. Dysregulation of soluble epoxide hydrolase and lipidomic profiles in anorexia nervosa

    KAUST Repository

    Shih, P. B.; Yang, J.; Morisseau, C.; German, J. B.; Scott-Van Zeeland, A. A.; Armando, A. M.; Quehenberger, O.; Bergen, A. W.; Magistretti, Pierre J.; Berrettini, W.; Halmi, K. A.; Schork, N.; Hammock, B. D.; Kaye, W.

    2015-01-01

    Individuals with anorexia nervosa (AN) restrict eating and become emaciated. They tend to have an aversion to foods rich in fat. Because epoxide hydrolase 2 (EPHX2) was identified as a novel AN susceptibility gene, and because its protein product

  20. General regularities of olefin epoxidation by hydroperoxide catalyzed by V, W and Ti compounds

    International Nuclear Information System (INIS)

    Sapunov, V.N.; Sharykin, V.G.; Logvinov, A.S.; Litvintsev, I.Yu.; Lebedev, N.N.

    1983-01-01

    The kinetic analysis of cyclohexane epoxidation by ethylbenzene hydroperoxide when catalyzed by titanium- and tungsten cyclohexandiolates has shown that the reaction follows the main regularities of hydroperoxide epoxidation previously established for catalysis by molybdenum- and vanadiUm compounds. The catalyst activity varies depending on the metal nature and forms the following series: Mo>V>W>Ti, which agrees with their π-acceptor capacity. During the cyclohexane epoxidation on all catalysts the hydroperoxide activities vary according to the following series: ethylbenzene hydroperoxide>cumene>tertiarybutyl>tertiaryamyl. Correlation relationships between the olefine structure, characterized by th constants, and the reactivity of olefines are foUnd. The reaction sensitivity during catalysis by WV, and Ti cyclohexandiolates is -1.2, -1.0- and -1.3, respectively. The mechanism of hydroperoxide epoxidation of olefine is discussed

  1. Purification and characterisation of a novel enantioselective epoxide hydrolase from Aspergillus niger M200

    Czech Academy of Sciences Publication Activity Database

    Kotík, Michael; Kyslík, Pavel

    2006-01-01

    Roč. 1760, - (2006), s. 245-252 ISSN 0006-3002 Institutional research plan: CEZ:AV0Z50200510 Keywords : epoxide hydrolase * enantioselectivity * aspergillus niger Subject RIV: EE - Microbiology, Virology

  2. High-temperature epoxidation of soybean oil in flow : speeding up elemental reactions wanted and unwanted

    NARCIS (Netherlands)

    Cortese, B.; Croon, de M.H.J.M.; Hessel, V.

    2012-01-01

    The soybean oil epoxidation reaction is investigated theoretically through kinetic modeling of temperature effects enabled through flow processing under superheated conditions. Different from previous studies on such processing, here a complex reaction network superimposed by multiphase transport is

  3. Aqueous benzene-diols react with an organic triplet excited state and hydroxyl radical to form secondary organic aerosol.

    Science.gov (United States)

    Smith, Jeremy D; Kinney, Haley; Anastasio, Cort

    2015-04-21

    Chemical processing in atmospheric aqueous phases, such as cloud and fog drops, can play a significant role in the production and evolution of secondary organic aerosol (SOA). In this work we examine aqueous SOA production via the oxidation of benzene-diols (dihydroxy-benzenes) by the triplet excited state of 3,4-dimethoxybenzaldehyde, (3)DMB*, and by hydroxyl radical, ˙OH. Reactions of the three benzene-diols (catechol (CAT), resorcinol (RES) and hydroquinone (HQ)) with (3)DMB* or ˙OH proceed rapidly, with rate constants near diffusion-controlled values. The two oxidants exhibit different behaviors with pH, with rate constants for (3)DMB* increasing as pH decreases from pH 5 to 2, while rate constants with ˙OH decrease in more acidic solutions. Mass yields of SOA were near 100% for all three benzene-diols with both oxidants. We also examined the reactivity of atmospherically relevant mixtures of phenols and benzene-diols in the presence of (3)DMB*. We find that the kinetics of phenol and benzene-diol loss, and the production of SOA mass, in mixtures are generally consistent with rate constants determined in experiments containing a single phenol or benzene-diol. Combining our aqueous kinetic and SOA mass yield data with previously published gas-phase data, we estimate a total SOA production rate from benzene-diol oxidation in a foggy area with significant wood combustion to be nearly 0.6 μg mair(-3) h(-1), with approximately half from the aqueous oxidation of resorcinol and hydroquinone, and half from the gas-phase oxidation of catechol.

  4. Development of cationically initiated UV curable coating systems based on cyclo-aliphatic diepoxide, ENR, epoxidized poly-butadiene and epoxidized soybean oil

    International Nuclear Information System (INIS)

    Kumar, R.N.; Quah, S.H.; Kong, K.W.; Rozman, H.D.; Tin, W.C.

    1999-01-01

    Epoxidized Natural Rubber (ENR) had been earlier found to impart toughness to otherwise brittle epoxy resin. Since the high viscosity of solutions of ENR in reactive solvent glycidyl methacrylate,imposed a limitation to the incorporation of higher percentages of the elastomer to the epoxy systems, experiments were initiated to employ the liquid elastomer, namely, epoxidized polybutadiene In the formulations. 'Mixture Design', a statistical experimental design, was adopted to study the effect of compositional and process variables on the curing of surface coatings formulated from the above system by UV radiation initiated by cationic photo-initiators. This paper also reports the results of the experiments carded out with epoxidized soybean oil Employed as a flexibilizer in the cycloaliphatic epoxy-ENR system

  5. MWCNTs-Reinforced Epoxidized Linseed Oil Plasticized Polylactic Acid Nanocomposite and Its Electroactive Shape Memory Behaviour

    OpenAIRE

    Alam, Javed; Alam, Manawwer; Raja, Mohan; Abduljaleel, Zainularifeen; Dass, Lawrence

    2014-01-01

    A novel electroactive shape memory polymer nanocomposite of epoxidized linseed oil plasticized polylactic acid and multi-walled carbon nanotubes (MWCNTs) was prepared by a combination of solution blending, solvent cast technique, and hydraulic hot press moulding. In this study, polylactic acid (PLA) was first plasticized by epoxidized linseed oil (ELO) in order to overcome the major limitations of PLA, such as high brittleness, low toughness, and low tensile elongation. Then, MWCNTs were inc...

  6. Hydroxyl-substituted ladder polyethers via selective tandem epoxidation/cyclization sequence.

    Science.gov (United States)

    Czabaniuk, Lara C; Jamison, Timothy F

    2015-02-20

    A new and highly selective method for the synthesis of hydroxyl-substituted tetrahydropyrans is described. This method utilizes titanium(IV) isopropoxide and diethyl tartrate to perform a diastereoselective epoxidation followed by in situ epoxide activation and highly selective endo-cyclization to form the desired tetrahydropyran ring. The HIJ ring fragment of the marine ladder polyether yessotoxin was synthesized using this two-stage tactic that proceeds with high efficiency and excellent regioselectivity.

  7. Selective epoxidation of allylic alcohols with a titania-silica aerogel

    Energy Technology Data Exchange (ETDEWEB)

    Dusi, M.; Mallat, T.; Baiker, A. [Lab. of Technical Chemistry, Swiss Federal Inst. of Technology, ETH-Zentrum, Zuerich (Switzerland)

    1998-12-31

    An amorphous mesoporous titania-silica aerogel (20 wt%TiO{sub 2} - 80 wt% SiO{sub 2}) and tert.-butylhydroperoxide (TBHP) have been used for the epoxidation of various allylic alcohols. Allylic alcohols possessing an internal double bond were more reactive than those with a terminal C=C bond. Epoxide selectivities could be improved by addition of (basic) zeolite 4 A and NaHCO{sub 3} to the reaction mixture. (orig.)

  8. A Dynamic Supramolecular System Exhibiting Substrate Selectivity in the Catalytic Epoxidation of Olefins

    DEFF Research Database (Denmark)

    Jonsson, Stefan; Odille, Fabrice G. J.; Norrby, Per-Ola

    2005-01-01

    A dynamic supramolecular system involving hydrogen bonding between a Mn(III) salen catalyst and a Zn(II) porphyrin receptor exhibits selectivity for pyridine appended cis-beta-substituted styrene derivatives over phenyl appended derivatives in a catalytic epoxidation reaction.......A dynamic supramolecular system involving hydrogen bonding between a Mn(III) salen catalyst and a Zn(II) porphyrin receptor exhibits selectivity for pyridine appended cis-beta-substituted styrene derivatives over phenyl appended derivatives in a catalytic epoxidation reaction....

  9. Ultrasound-assisted chemoenzymatic epoxidation of soybean oil by using lipase as biocatalyst.

    Science.gov (United States)

    Bhalerao, Machhindra S; Kulkarni, Vaishali M; Patwardhan, Anand V

    2018-01-01

    The present work reports the use of ultrasonic irradiation for enhancing lipase catalyzed epoxidation of soybean oil. Higher degree of unsaturated fatty acids, present in the soybean oil was converted to epoxidized soybean oil by using an immobilized lipase, Candida antarctica (Novozym 435). The effects of various parameters on the relative percentage conversion of the double bond to oxirane oxygen were investigated and the optimum conditions were established. The parameters studied were temperature, hydrogen peroxide to ethylenic unsaturation mole ratio, stirring speed, solvent ratio, catalyst loading, ultrasound frequency, ultrasound input power and duty cycle. The main objective of this work was to intensify chemoenzymatic epoxidation of the soybean oil by using ultrasound, to reduce the time required for epoxidation. Epoxidation of the soybean oil was achieved under mild reaction conditions by indirect ultrasonic irradiations (using ultrasonic bath). The relative percentage conversion to oxirane oxygen of 91.22% was achieved within 5h. The lipase was remarkably stable under optimized reaction conditions, later was recovered and reused six times to produce epoxidized soybean oil (ESO). Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Solubility and thermodynamic behavior of vanillin in propane-1,2-diol+water cosolvent mixtures at different temperatures.

    Science.gov (United States)

    Shakeel, Faiyaz; Haq, Nazrul; Siddiqui, Nasir A; Alanazi, Fars K; Alsarra, Ibrahim A

    2015-12-01

    The solubilities of bioactive compound vanillin were measured in various propane-1,2-diol+water cosolvent mixtures at T=(298-318)K and p=0.1 MPa. The experimental solubility of crystalline vanillin was determined and correlated with calculated solubility. The results showed good correlation of experimental solubilities of crystalline vanillin with calculated ones. The mole fraction solubility of crystalline vanillin was recorded highest in pure propane-1,2-diol (7.06×10(-2) at 298 K) and lowest in pure water (1.25×10(-3) at 298 K) over the entire temperature range investigated. Thermodynamic behavior of vanillin in various propane-1,2-diol+water cosolvent mixtures was evaluated by Van't Hoff and Krug analysis. The results showed an endothermic, spontaneous and an entropy-driven dissolution of crystalline vanillin in all propane-1,2-diol+water cosolvent mixtures. Based on solubility data of this work, vanillin has been considered as soluble in water and freely soluble in propane-1,2-diol. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Zirconium-doped magnetic microspheres for the selective enrichment of cis-diol-containing ribonucleosides.

    Science.gov (United States)

    Fan, Hua; Chen, Peihong; Wang, Chaozhan; Wei, Yinmao

    2016-05-27

    Zirconium-doped magnetic microspheres (Zr-Fe3O4) for the selective enrichment of cis-diol-containing biomolecules were easily synthesized via a one-step hydrothermal method. Characterization of the microspheres revealed that zirconium was successfully doped into the lattice of Fe3O4 at a doping level of 4.0 at%. Zr-Fe3O4 possessed good magnetic properties and high specificity towards cis-diol molecules, as shown using 28 compounds. For ribonucleosides, the adsorbent not only has favorable anti-interferential abilities but also has a high adsorption capacity up to 159.4μmol/g. As an example of a real application, four ribonucleosides in urine were efficiently enriched and detected via magnetic solid-phase extraction coupled with high-performance liquid chromatography. Under the optimized extraction conditions, the detection limits were determined to be between 0.005 and 0.017μg/mL, and the linearities ranged from 0.02 to 5.00μg/mL (R≥0.996) for these analytes. The accuracy of the analytical method was examined by studying the relative recoveries of the analytes in real urine samples, with recoveries varying from 77.8% to 119.6% (RSDs<10.6%, n=6). The results indicate that Zr-Fe3O4 is a suitable adsorbent for the analysis of cis-diol-containing biomolecules in practical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Impact of Stereochemistry on Ligand Binding: X-ray Crystallographic Analysis of an Epoxide-Based HIV Protease Inhibitor.

    Science.gov (United States)

    Benedetti, Fabio; Berti, Federico; Campaner, Pietro; Fanfoni, Lidia; Demitri, Nicola; Olajuyigbe, Folasade M; De March, Matteo; Geremia, Silvano

    2014-09-11

    A new pseudopeptide epoxide inhibitor, designed for irreversible binding to HIV protease (HIV-PR), has been synthesized and characterized in solution and in the solid state. However, the crystal structure of the complex obtained by inhibitor-enzyme cocrystallization revealed that a minor isomer, with inverted configuration of the epoxide carbons, has been selected by HIV-PR during crystallization. The structural characterization of the well-ordered pseudopeptide, inserted in the catalytic channel with its epoxide group intact, provides deeper insights into inhibitor binding and HIV-PR stereoselectivity, which aids development of future epoxide-based HIV inhibitors.

  13. Ultrasonicated Synthesis of N-Benzyl-2,3-substituted Morpholines, via the Mitsunobu Diol Cyclisation

    Directory of Open Access Journals (Sweden)

    B. Jayachandra Reddy

    2010-01-01

    Full Text Available A facile five step synthesis of N-benzyl-2,3-substituted morpholines (i-iii was performed. The key steps were microwave assisted Friedel-crafts acylation and diol cyclization carried out via an ultra sonication of Mitsunobu reaction using DEAD (diethylazodicarboxylate, TPP in THF for 1 h. The morpholine products were generated as diasteriomers (ii andiii which has been separated by the column chromatography to good yield. The structure of compounds (i-iii has been characterized by the spectral and chemical studies.

  14. Synthesis of tritium labeled 4-androstenedione, 4-androsten 3α and 3β diols

    International Nuclear Information System (INIS)

    Matei, Lidia; Postolache, C.; Chiper, Diana; Tuta, C.; Bubueanu, G; Tanase, C.

    2009-01-01

    Androgen dependent diseases can appear due to blocking in different stages of biosynthesis of sexual hormones (testosterone, dihydrotestosterone) or to some modification in signalizing pathways through androgen receptor. In the diagnosis of these diseases which appear both in men and women (polycystic ovaries, hirsutism) it is also important the enzymatic activity determination of some key enzymes in steroid genesis steroid 5α-reductase, 3α and 3β-hydroxy-steroid-dehydrogenase, 17β- hydroxy-steroid-dehydrogenase. In this paper, we describe the method of obtaining tritium labeled 4-androstenedione, 4-androsten 3α and 3β diols by biosynthesis and chemical synthesis with testosterone used as substrate. (authors)

  15. Correlation analysis of reactivity in the oxidation of some organic diols by tripropylammonium fluorochromate in non-aqueous media

    Directory of Open Access Journals (Sweden)

    S. Sheik Mansoor

    2016-09-01

    Full Text Available The kinetics of oxidation of some organic diols by tripropylammonium fluorochromate (TriPAFC have been studied in dimethylsulfoxide (DMSO. The main product of oxidation is the corresponding hydroxy aldehydes. The reaction is first order with respect to TriPAFC and exhibited Michaelis-Menten type kinetics with respect to organic diols. The reaction is catalyzed by hydrogen ions. The hydrogen ion dependence has the form: kobs = a + b[H+]. Various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of isokinetic relationship. Oxidation of diols was studied in 18 different organic solvents. The rate data are showing satisfactory correlation with Kamlet–Taft solvotochromic parameters (α, β and π∗. A suitable mechanism of oxidation has been proposed.

  16. Epoxide-mediated differential packaging of Cif and other virulence factors into outer membrane vesicles.

    Science.gov (United States)

    Ballok, Alicia E; Filkins, Laura M; Bomberger, Jennifer M; Stanton, Bruce A; O'Toole, George A

    2014-10-01

    Pseudomonas aeruginosa produces outer membrane vesicles (OMVs) that contain a number of secreted bacterial proteins, including phospholipases, alkaline phosphatase, and the CFTR inhibitory factor (Cif). Previously, Cif, an epoxide hydrolase, was shown to be regulated at the transcriptional level by epoxides, which serve as ligands of the repressor, CifR. Here, we tested whether epoxides have an effect on Cif levels in OMVs. We showed that growth of P. aeruginosa in the presence of specific epoxides but not a hydrolysis product increased Cif packaging into OMVs in a CifR-independent fashion. The outer membrane protein, OprF, was also increased under these conditions, but alkaline phosphatase activity was not significantly altered. Additionally, we demonstrated that OMV shape and density were affected by epoxide treatment, with two distinct vesicle fractions present when cells were treated with epibromohydrin (EBH), a model epoxide. Vesicles isolated from the two density fractions exhibited different protein profiles in Western blotting and silver staining. We have shown that a variety of clinically or host-relevant treatments, including antibiotics, also alter the proteins packaged in OMVs. Proteomic analysis of purified OMVs followed by an analysis of transposon mutant OMVs yielded mutants with altered vesicle packaging. Finally, epithelial cell cytotoxicity was reduced in the vesicles formed in the presence of EBH, suggesting that this epoxide alters the function of the OMVs. Our data support a model whereby clinically or host-relevant signals mediate differential packaging of virulence factors in OMVs, which results in functional consequences for host-pathogen interactions. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  17. Epoxide hydrolase affects estrogen production in the human ovary.

    Science.gov (United States)

    Hattori, N; Fujiwara, H; Maeda, M; Fujii, S; Ueda, M

    2000-09-01

    To investigate the mechanisms of ovarian cell differentiation, we raised a new monoclonal antibody, HCL-3, which reacted with human luteal cells. It also reacted with human and porcine hepatocytes. The immunoaffinity-purified HCL-3 antigen from human corpora lutea (CL) was shown to be a 46-kDa protein. The N-terminal 22 amino acids of the 46-kDa protein from porcine liver exhibited high homology (82%) to human microsomal epoxide hydrolase (mEH). The purified HCL-3 antigen from human CL or porcine liver showed EH enzyme activity, confirming that HCL-3 antigen is identical to mEH, which is reported to detoxify the toxic substrates in the liver. In human follicles, mEH was immunohistochemically detected on granulosa and theca interna cells. In the menstrual and pregnant CL, mEH was also expressed on large and small luteal cells. A competitive inhibitor of EH, 1,2-epoxy-3,3,3-trichloropropane, inhibited the conversion of estradiol from testosterone by granulosa cells cultured in vitro, indicating the involvement of mEH in ovarian estrogen production. Because anticonvulsant sodium valproate and its analogues were reported to inhibit EH enzyme activity, these findings provide a new insight into the etiology of endocrine disorders that are frequently observed among epileptic patients taking anticonvulsant drugs.

  18. Soluble epoxide hydrolase inhibitory activity of anthraquinone components from Aloe.

    Science.gov (United States)

    Sun, Ya Nan; Kim, Jang Hoon; Li, Wei; Jo, A Reum; Yan, Xi Tao; Yang, Seo Young; Kim, Young Ho

    2015-10-15

    Aloe is a short-stemmed succulent herb widely used in traditional medicine to treat various diseases and as raw material in cosmetics and heath foods. In this study, we isolated and identified two new anthraquinone derivatives, aloinoside C (6) and aloinoside D (7), together with six known compounds from an aqueous dissolved Aloe exudate. Their structures were identified by spectroscopic analysis. The inhibitory effects of the isolated compounds on soluble epoxide hydrolase (sEH) were evaluated. Compounds 1-8 inhibited sEH activity potently, with IC50 values ranging from 4.1±0.6 to 41.1±4.2 μM. A kinetic analysis of compounds 1-8 revealed that the inhibitory actions of compounds 1, 6 and 8 were non-competitive, whereas those of compounds 2-5 and 7 were the mixed-type. Molecular docking increases our understanding of receptor-ligand binding of all compounds. These results demonstrate that compounds 1-8 from Aloe are potential sEH inhibitors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Cancer risk estimation for mixtures of coal tars and benzo(a)pyrene

    International Nuclear Information System (INIS)

    Gaylor, D.W.; Culp, S.J.; Goldstein, L.S.; Beland, F.A.

    2000-01-01

    Two-year chronic bioassays were conducted by using B6C3F1 female mice fed several concentrations of two different mixtures of coal tars from manufactured gas waste sites or benzo(a)pyrene (BaP). The purpose of the study was to obtain estimates of cancer potency of coal tar mixtures, by using conventional regulatory methods, for use in manufactured gas waste site remediation. A secondary purpose was to investigate the validity of using the concentration of a single potent carcinogen, in this case benzo(a)pyrene, to estimate the relative risk for a coal tar mixture. The study has shown that BaP dominates the cancer risk when its concentration is greater than 6,300 ppm in the coal tar mixture. In this case the most sensitive tissue site is the forestomach. Using low-dose linear extrapolation, the lifetime cancer risk for humans is estimated to be: Risk -4 (ppm coal tar in total diet) + 240 x 10 -4 (ppm BaP in total diet), based on forestomach tumors. If the BaP concentration in the coal tar mixture is less than 6,300 ppm, the more likely case, then lung tumors provide the largest estimated upper limit of risk, Risk -4 (ppm coal tar in total diet), with no contribution of BaP to lung tumors. The upper limit of the cancer potency (slope factor) for lifetime oral exposure to benzo(a)pyrene is 1.2 x 10 -3 per microg per kg body weight per day from this Good Laboratory Practice (GLP) study compared with the current value of 7.3 x 10 -3 per microg per kg body weight per day listed in the US EPA Integrated Risk Information System

  20. Interspecies differences in the enantioselectivity of epoxide hydrolases in Cryptococcus laurentii (Kufferath) C.E. Skinner and Cryptococcus podzolicus (Bab'jeva & Reshetova) Golubev

    CSIR Research Space (South Africa)

    Botes, AL

    2005-01-01

    Full Text Available Isolates representing Cryptococcus laurentii and Cryptococcus podzolicus, originating from soil of a heath land indigenous to South Africa, were screened for the presence of enantioselective epoxide hydrolases for 2, 2-disubstituted epoxides...

  1. Multimedia transport of particle-bound organics: benzo(a)pyrene test case

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, P A; Cohen, Y

    1986-01-01

    A screening multimedia-compartmental (MCM) modeling approach is presented for predicting the distribution of particle-bound pollutants within an environment consisting of the atmosphere, surface water, and surface soil compartments. An MCM model was used to simulate the dynamic distribution of Benzo(a)Pyrene (B(a)P) for a study region located in southeast Ohio. The model incorporates theoretical estimates of the dry deposition velocity and a new semi-empirical model for rain scavenging of B(a)P. The predicted concentrations of B(a)P compared favorably with available field data.

  2. Occurrence of neoxanthin and lutein epoxide cycle in parasitic Cuscuta species.

    Science.gov (United States)

    Kruk, Jerzy; Szymańska, Renata

    2008-01-01

    In the present study, xanthophyll composition of eight parasitic Cuscuta species under different light conditions was investigated. Neoxanthin was not detected in four of the eight species examined, while in others it occurred at the level of several percent of total xanthophylls. In C. gronovii and C. lupuliformis it was additionally found that the neoxanthin content was considerably stimulated by strong light. In dark-adapted plants, lutein epoxide level amounted to 10-22% of total xanthophylls in only three species, the highest being for C. lupuliformis, while in others it was below 3%, indicating that the lutein epoxide cycle is limited to only certain Cuscuta species. The obtained data also indicate that the presence of the lutein epoxide cycle and of neoxanthin is independent and variable among the Cuscuta species. The xanthophyll cycle carotenoids violaxanthin, antheraxanthin and zeaxanthin were identified in all the examined species and occurred at the level found in other higher plants. The xanthophyll and lutein epoxide cycle pigments showed typical response to high light stress. The obtained results also suggest that the ability of higher plants to synthesize lutein epoxide probably does not depend on the substrate specificity of zeaxanthin epoxidase but on the availability of lutein for the enzyme.

  3. Kinetics of the Epoxidation of Geraniol and Model Systems by Dimethyldioxirane

    Directory of Open Access Journals (Sweden)

    B. S. Crow

    2004-02-01

    Full Text Available The mono-epoxidation of geraniol by dimethyldioxirane was carried out invarious solvents. In all cases, the product ratios for the 2,3 and 6,7 mono-epoxides werein agreement with literature values. Kinetic studies were carried out at 23 oC in thefollowing dried solvent systems: acetone (k2 = 1.49 M-1s-1, carbon tetrachloride/acetone(9/1, k2=2.19 M-1s-1, and methanol/acetone (9/1, k2 = 17 M-1s-1. Individual k2 valueswere calculated for epoxidation of the 2,3 and 6,7 positions in geraniol. The non-conjugated diene system was modeled employing two simple independent alkenes:2-methyl-2-pentene and 3-methyl-2-buten-1-ol by determining the respective k2 valuesfor epoxidation in various solvents. The kinetic results for each independent alkeneshowed that the relative reactivity of the two epoxidation sites in geraniol as a function ofsolvent was not simply a summation of the independent alkene systems.

  4. Cycloadditions to Epoxides Catalyzed by GroupIII-V Transition-Metal Complexes

    KAUST Repository

    D'Elia, Valerio

    2015-05-25

    Complexes of groupIII-V transition metals are gaining increasing importance as Lewis acid catalysts for the cycloaddition of dipolarophiles to epoxides. This review examines the latest reports, including homogeneous and heterogeneous applications. The pivotal step for the cycloaddition reactions is the ring opening of the epoxide following activation by the Lewis acid. Two modes of cleavage (C-C versus C-O) have been identified depending primarily on the substitution pattern of the epoxide, with lesser influence observed from the Lewis acid employed. The widely studied cycloaddition of CO2 to epoxides to afford cyclic carbonates (C-O bond cleavage) has been scrutinized in terms of catalytic efficiency and reaction mechanism, showing that unsophisticated complexes of groupIII-V transition metals are excellent molecular catalysts. These metals have been incorporated, as well, in highly performing, recyclable heterogeneous catalysts. Cycloadditions to epoxides with other dipolarophiles (alkynes, imines, indoles) have been conducted with scandium triflate with remarkable performances (C-C bond cleavage). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Cycloadditions to Epoxides Catalyzed by GroupIII-V Transition-Metal Complexes

    KAUST Repository

    D'Elia, Valerio; Pelletier, Jeremie; Basset, Jean-Marie

    2015-01-01

    Complexes of groupIII-V transition metals are gaining increasing importance as Lewis acid catalysts for the cycloaddition of dipolarophiles to epoxides. This review examines the latest reports, including homogeneous and heterogeneous applications. The pivotal step for the cycloaddition reactions is the ring opening of the epoxide following activation by the Lewis acid. Two modes of cleavage (C-C versus C-O) have been identified depending primarily on the substitution pattern of the epoxide, with lesser influence observed from the Lewis acid employed. The widely studied cycloaddition of CO2 to epoxides to afford cyclic carbonates (C-O bond cleavage) has been scrutinized in terms of catalytic efficiency and reaction mechanism, showing that unsophisticated complexes of groupIII-V transition metals are excellent molecular catalysts. These metals have been incorporated, as well, in highly performing, recyclable heterogeneous catalysts. Cycloadditions to epoxides with other dipolarophiles (alkynes, imines, indoles) have been conducted with scandium triflate with remarkable performances (C-C bond cleavage). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Anti-Leishmania and cytotoxic activities of perillaldehyde epoxide synthetic positional isomers.

    Science.gov (United States)

    Keesen, Tatjana Souza Lima; da Silva, Larisse Virgolino; da Câmara Rocha, Juliana; Andrade, Luciana Nalone; Lima, Tamires Cardoso; de Sousa, Damião Pergentino

    2018-03-13

    Leishmaniasis belongs to a complex of zoonotic disease caused by protozoa of the genus Leishmania and is considered a major public health problem. Several essential oil chemical components have inhibitory effect against protozoa, including Leishmania donovani. Thus, the aim of this study was to evaluate for the first time the anti-Leishmania activity of two p-menthane monoterpene isomers (EPER-1: perillaldehyde 1,2-epoxide and EPER-2: perillaldehyde 8,9-epoxide) against L. donovani promastigotes as well as evaluating cytotoxic effect on mononuclear peripheral blood cells. Results of anti-Leishmania assay revealed that EPER-2 (IC 50  = 3.8 μg.mL -1 ) was 16-fold more potent than its isomer EPER-1 (IC 50  = 64.6 μg.mL -1 ). In contrast to PBMC cells, EPER-2 was not cytotoxic (IC 50  > 400 μg.mL -1 ) when compared to positive control. These data suggest that the disposition of epoxide group into the p-menthane skeleton affects the anti-Leishmania activity, being that the presence of the exocyclic epoxide group considerably increased potency. Thus, it was possible to observe that the location of the epoxide group into the p-menthane skeleton resulted in different potencies.

  7. Chemo-enzymatic epoxidation of olefins by carboxylic acid esters and hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ruesch gen. Klaas, M.; Warwel, S. [Inst. for Biochemistry and Technology of Lipids, H.P. Kaufmanm-Inst., Federal Centre for Cereal, Potato and Lipid Research, Muenster (Germany)

    1998-12-31

    Ethylen and, recently, butadiene can be epoxidized directly with oxygen and for the epoxidation of propylene, the use of heterogeneous transition metals and organic peroxides (Halcon-Process) is the major player. But, beside from those notable exceptions, all other epoxidations, including large ones like the epoxidation of plant oils as PVC-stabilizers (about 200.000 t/year), are carried out with peroxy acids. Because mcpba is far to expensive for most applications, short chain peracids like peracetic acid are used. Being much less stable than mcpba and thus risky handled in large amounts and high concentrations, these peroxy acids were preferably prepared in-situ. However, conventional in-situ formation of peracids has the serious drawback, that a strong acid is necessary to catalyze peroxy acid formation from the carboxylic acid and hydrogen peroxide. The presence of a strong acid in the reaction mixture often results in decreased selectivity because of the formation of undesired by-products by opening of the oxirane ring. Therefore, we propose a new method for epoxidation based on the in-situ preparation of percarboxylic acids from carboxylic acid esters and hydrogen peroxide catalyzed by a commercial, immobilized lipase. (orig.)

  8. Isotope labelling study of CO oxidation-assisted epoxidation of propene. Implications for oxygen activation on Au catalysts.

    Science.gov (United States)

    Jiang, Jian; Oxford, Sean M; Fu, Baosong; Kung, Mayfair C; Kung, Harold H; Ma, Jiantai

    2010-06-07

    (18)O isotope labelling studies of the CO oxidation-assisted epoxidation of propene, catalyzed by a mixture of Au/TiO(2) and TS-1, using a methanol-H(2)O solvent showed the O in the epoxide was exclusively from O(2) and not H(2)O or methanol.

  9. Hydroperoxide-dependent oxygenation of polycyclic aromatic hydrocarbons and their metabolites

    International Nuclear Information System (INIS)

    Marnett, L.J.

    1985-01-01

    Fatty acid hydroperoxides in the presence of heme complexes and heme proteins oxidize benzo(a)pyrene and 7,8-dihydroxy-7, 8-dihydrobenzo(a)pyrene to quinones and diol epoxides, respectively. The oxidizing agent is a peroxyl radical derived from the fatty acid hydroperoxide but not a higher oxidation state of a mammalian peroxidase. The stereochemistry of (+-)-BP-dihydrodiol epoxidation is distinct from that catalyzed by mixed-function oxidases, which provides a convenient method for discriminating the contributions of the two systems to BP-7,8-dihydrodiol metabolism in cell homogenates, cell or organ culture. Using this method, epoxidation of BP-7,89-dihydroodiol has been detected during prostaglandin biosynthesis, lipid peroxidation, and xenobiotic oxygenation. Fatty acid hydroperoxide-dependent oxidation constitutes a novel pathway for metabolic activation of polycyclic hydrocarbons and other carcinogens which has widespread potential in vivo significance

  10. Preparation of Epoxidized Palm Olein as Renewable Material by Using Peroxy Acids

    International Nuclear Information System (INIS)

    Darfizzi Derawi; Jumat Salimon; Waled Abdo Ahmed

    2014-01-01

    Epoxidized palm olein (EPO o ) was prepared through generated in situ of performic acid (HCOOOH), and peracetic acid (CH 3 COOOH) as epoxidation agent with the presence of sulphuric acid (H 2 SO 4 ) 3 % v/ wt as catalyst. Formic acid (HCOOH) or acetic acid (CH 3 COOH) as oxygen carrier and hydrogen peroxide (H 2 O 2 ) as oxygen donor in the reaction system. Highly conversion (95.5 %) of oxirane ring was obtained by using performic acid as epoxidation agent at 150 minutes of reaction time. The reaction yield was 90 % by weight. EPO o has showed good physicochemical properties as renewable material for industrial applications. Carbon ( 13 C-NMR) and proton ( 1 H-NMR) spectra showed the present of epoxy profile at 54 ppm and 2.9 ppm. Epoxy group was detected on 844 cm -1 by fourier transformation infra-red (FTIR) spectra. (author)

  11. Evaluation of fish models of soluble epoxide hydrolase inhibition.

    Science.gov (United States)

    Newman, J W; Denton, D L; Morisseau, C; Koger, C S; Wheelock, C E; Hinton, D E; Hammock, B D

    2001-01-01

    Substituted ureas and carbamates are mechanistic inhibitors of the soluble epoxide hydrolase (sEH). We screened a set of chemicals containing these functionalities in larval fathead minnow (Pimphales promelas) and embryo/larval golden medaka (Oryzias latipes) models to evaluate the utility of these systems for investigating sEH inhibition in vivo. Both fathead minnow and medaka sEHs were functionally similar to the tested mammalian orthologs (murine and human) with respect to substrate hydrolysis and inhibitor susceptibility. Low lethality was observed in either larval or embryonic fish exposed to diuron [N-(3,4-dichlorophenyl), N'-dimethyl urea], desmethyl diuron [N-(3,4-dichlorophenyl), N'-methyl urea], or siduron [N-(1-methylcyclohexyl), N'-phenyl urea]. Dose-dependent inhibition of sEH was a sublethal effect of substituted urea exposure with the potency of siduron diuron = diuron, differing from the observed in vitro sEH inhibition potency of siduron > desmethyl diuron > diuron. Further, siduron exposure synergized the toxicity of trans-stilbene oxide in fathead minnows. Medaka embryos exposed to diuron, desmethyl diuron, or siduron displayed dose-dependent delays in hatch, and elevated concentrations of diuron and desmethyl diuron produced developmental toxicity. The dose-dependent toxicity and in vivo sEH inhibition correlated, suggesting a potential, albeit undefined, relationship between these factors. Additionally, the observed inversion of in vitro to in vivo potency suggests that these fish models may provide tools for investigating the in vivo stability of in vitro inhibitors while screening for untoward effects. PMID:11171526

  12. Enantioselective epoxidation with chiral MN(III)(salen) catalysts: kinetic resolution of aryl-substituted allylic alcohols.

    Science.gov (United States)

    Adam, W; Humpf, H U; Roschmann, K J; Saha-Möller, C R

    2001-08-24

    A set of aryl-substituted allylic alcohols rac-2 has been epoxidized by chiral Mn(salen*) complexes 1 as the catalyst and iodosyl benzene (PhIO) as the oxygen source. Whereas one enantiomer of the allylic alcohol 2 is preferentially epoxidized to give the threo- or cis-epoxy alcohol 3 (up to 80% ee) as the main product (dr up to >95:5), the other enantiomer of 2 is enriched (up to 53% ee). In the case of 1,1-dimethyl-1,2-dihydronaphthalen-2-ol (2c), the CH oxidation to the enone 4c proceeds enantioselectively and competes with the epoxidation. The absolute configurations of the allylic alcohols 2 and their epoxides 3 have been determined by chemical correlation or CD spectroscopy. The observed diastereo- and enantioselectivities in the epoxidation reactions are rationalized in terms of a beneficial interplay between the hydroxy-directing effect and the attack along the Katsuki trajectory.

  13. Impact of culturing conditions on the abundance and composition of long chain alkyl diols in species of the genus

    NARCIS (Netherlands)

    Balzano, S.; Villanueva, L.; de Bar, M.; Sinninghe Damsté, J.S.; Schouten, S.

    2017-01-01

    Long chain alkyl diols (LCDs) are widespread in sediments and are synthesized, among others, by microalgae of the genus Nannochloropsis. The factors regulating the synthesis of LCDs and their biological function are, however, unclear. We investigated the changes in abundance of free + ester-bound

  14. Ruthenium-catalysed synthesis of 2- and 3-substituted quinolines from anilines and 1,3-diols

    DEFF Research Database (Denmark)

    Monrad, Rune Nygaard; Madsen, Robert

    2011-01-01

    A straightforward synthesis of substituted quinolines is described by cyclocondensation of anilines with 1,3-diols. The reaction proceeds in mesitylene solution with catalytic amounts of RuCl3·xH 2O, PBu3 and MgBr2·OEt2. The transformation does not require any stoichiometric additives and only...

  15. Femtosecond double proton transfer dynamics in [2,2'-bipyridyl]-3,3'-diol in sol-gel glasses

    NARCIS (Netherlands)

    Prosposito, P.; Marks, D.R.A.; Zhang, H.; Glasbeek, M.

    1998-01-01

    Abstract: Intramolecular excited state double proton-transfer dynamics has been studied for [2,2'-bipyridyl]-3,3'-diol (BP(OH)2) in sol-gel glass. By means of the femtosecond fluorescence up-conversion technique, the spectral dependence of the fluorescence transients obtained for BP(OH)2 in a few

  16. The introduction of a double bond on the steroid skeleton - the preparation of enol silyl ether derivatives from vicinal diols

    Czech Academy of Sciences Publication Activity Database

    Marek, Aleš; Klepetářová, Blanka; Elbert, Tomáš

    2011-01-01

    Roč. 76, č. 5 (2011), s. 443-456 ISSN 0010-0765 R&D Projects: GA AV ČR IAA400550801 Institutional research plan: CEZ:AV0Z40550506 Keywords : enol silyl ether * vicinal diol * steroids Subject RIV: CC - Organic Chemistry Impact factor: 1.283, year: 2011

  17. Facile and Highly Diastereoselective Synthesis of syn- and cis-1,2-Diol Derivatives from Protected alpha-Hydroxy Ketones

    Czech Academy of Sciences Publication Activity Database

    Jahn, Emanuela; Smrček, Jakub; Pohl, Radek; Císařová, I.; Jones, P. G.; Jahn, Ullrich

    2015-01-01

    Roč. 2015, č. 35 (2015), s. 7785-7798 ISSN 1434-193X Grant - others:COST(XE) CM1201 Institutional support: RVO:61388963 Keywords : synthetic methods * reduction * diastereoselectivity * diols * ketones Subject RIV: CC - Organic Chemistry Impact factor: 3.068, year: 2015

  18. Nucleoside adducts from the in vitro reaction of benzo[a]pyrene-7,8-dihydrodiol 9,10-oxide or benzo[a]pyrene 4,5-oxide with nucleic acids.

    Science.gov (United States)

    Jennette, K W; Jeffrey, A M; Blobstein, S H; Beland, F A; Harvey, R G; Weinstein, I B

    1977-03-08

    The covalent binding of benzo[a]pyrene 4,5-oxide and benzo[a]pyrene-7,8-dihydrodiol 9,10-oxide isomer I and isomer II to nucleic acids in aqueous acetone solution has been investigated. Benzo[a]pyrene 4,5-oxide reacted preferentially with guanosine residues. On the other hand, benzo[a]pyrene-7,8-dihydrodiol 9,10-oxide isomer I and II reacted extensively with guanosine, adenosine, and cytidine residues. Time course studies showed that the reactivity of isomer I or isomer II with homopolyribonucleotides followed the order poly(G) greater than poly(A) greater than poly(C). Alkaline or enzymatic hydrolysis of the modified nucleic acids and subsequent chromatography on Sephadex LH-20 columns yielded benzo[a]pyrene-nucleotide adducts. These were enzymatically converted to the corresponding nucleosides which were resolved into several distinct components by high-pressure liquid chromatography. Evidence was obtained for the presence of multiple nucleoside adducts of guanosine, adenosine, cytidine, deoxyguanosine, deoxyadenosine, and deoxycytidine. The HPLC profiles of adducts formed with isomer I were different from the corresponding profiles of adducts formed with isomer II. Structural aspects of these nucleoside adducts are discussed.

  19. Green chemistry: Efficient epoxides ring-opening with 1-butanol under microwave irradiation

    International Nuclear Information System (INIS)

    Garcia-Vidal, Jesus A.; Duran-Valle, Carlos J.; Ferrera-Escudero, Santiago

    2006-01-01

    Two activated carbons treated with mineral acids (HNO 3 and sulfonitric mixture) have been tested as acid catalysts in the epoxides (1,2-epoxyhexane and styrene oxide) ring-opening reaction with 1-butanol under microwave (MW) irradiation. The mayor obtained product is that resulting of the alcohol addition to the most substituted carbon in the epoxide ring. The most active catalyst is that treated with sulfonitric mixture. The use of a MW oven allows achieving to the complete conversion of styrene oxide in only 2 min

  20. Bonding two surfaces by exposing to actinic radiation an epoxide liquid composition

    International Nuclear Information System (INIS)

    Green, G.E.

    1981-01-01

    A method for preparing a film adhesive from an epoxide resin is described. A liquid containing an epoxide resin and a photopolymerizable compound is polymerized to form a solid continuous film by exposure to actinide radiation. A catalyst can be used but no thermal crosslinking should be allowed to occur. The film so obtained is used to bond surfaces together by the application of heat and pressure. The period of heating can be very short, as there need be no solvent to evaporate and the films need not be thick, typically 20 to 250 μm. (O.T.)

  1. Soybean epoxide production with in situ peracetic acid using homogeneous catalysis

    Directory of Open Access Journals (Sweden)

    Luis Alejandro Boyacá Mendivelso

    2010-01-01

    Full Text Available Using vegetable oils has become an excellent option for petrochemical product substitution. The epoxides obtained from such oils have wide applications as plastifiers and PVC stabilisers and as raw material in polyol synthesis for the polyurethane industry. This paper presents soybean oil epoxidation using a homogeneous catalyst in a well-mixed, stirred reactor being operated in iso- thermal conditions. The best result achieved was a 6.4% oxyrane oxygen content using hydrogen peroxide (25% molar excess, a- cetic acid (5% p/p and sulphuric acid (2% p/p concentrations at 80°C.

  2. Synthesis of Marine Polycyclic Polyethers via Endo-Selective Epoxide-Opening Cascades

    Directory of Open Access Journals (Sweden)

    Timothy F. Jamison

    2010-03-01

    Full Text Available The proposed biosynthetic pathways to ladder polyethers of polyketide origin and oxasqualenoids of terpenoid origin share a dramatic epoxide-opening cascade as a key step. Polycyclic structures generated in these biosynthetic pathways display biological effects ranging from potentially therapeutic properties to extreme lethality. Much of the structural complexity of ladder polyether and oxasqualenoid natural products can be traced to these hypothesized cascades. In this review we summarize how such epoxide-opening cascade reactions have been used in the synthesis of ladder polyethers and oxasqualenoid natural products.

  3. Epoxidation of cyclohexene by ethyl-benzene hydroperoxide in the presence of molybdenum catalyst

    International Nuclear Information System (INIS)

    Sapunov, V.N.; Litvintsev, I.Yu.; Margitfal'vi, J.; Lebedev, N.N.

    1977-01-01

    A study has been made of the kinetic experimental pattern and mechanism of epoxidation of cyclohexene by ethylbenzene hydroperoxide during catalysis by Mo(CO) 6 in various solvents. A first order of reaction with respect to the catalyst and complex order of reaction with respect to the hydroperoxide and olefine have been established. Simple (square and cross) inhibition by reaction products, cyclohexene oxide and methylphenylcarbinol, have been found. An increase in the dielectric constant of the solvent diminishes the epoxidation rate. The mechanism scheme of the process is proposed and main kinetic parameters calculated

  4. Green chemistry: Efficient epoxides ring-opening with 1-butanol under microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Vidal, Jesus A. [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Extremadura, Campus Universitario, Avda. de Elvas, s/n, E-06071-Badajoz (Spain); Duran-Valle, Carlos J. [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Extremadura, Campus Universitario, Avda. de Elvas, s/n, E-06071-Badajoz (Spain)]. E-mail: carlosdv@unex.es; Ferrera-Escudero, Santiago [Departamento de Quimica Inorganica y Quimica Tecnica, Universidad Nacional de Educacion a Distancia, C/Senda del Rey, 9, E-28040 Madrid (Spain)

    2006-06-30

    Two activated carbons treated with mineral acids (HNO{sub 3} and sulfonitric mixture) have been tested as acid catalysts in the epoxides (1,2-epoxyhexane and styrene oxide) ring-opening reaction with 1-butanol under microwave (MW) irradiation. The mayor obtained product is that resulting of the alcohol addition to the most substituted carbon in the epoxide ring. The most active catalyst is that treated with sulfonitric mixture. The use of a MW oven allows achieving to the complete conversion of styrene oxide in only 2 min.

  5. Characterization Study of EPDM Rubber Vulcanized by Gamma Radiation in The Presence of Epoxidized Soybean Oil

    International Nuclear Information System (INIS)

    Radi, H.; Mousaa, I.M.

    2015-01-01

    Composites based on ethylene-propylene-diene rubber (EPDM) were prepared. EPDM loaded with 40 phr fumed silica in the presence of different concentrations of epoxidized soybean oil ranging between 4 and 8 phr. The composites were subjected to various gamma irradiation doses up to 200 kGy. The physical, mechanical and thermal properties of rubber composition as a function of irradiation dose were investigated. Gamma irradiation led to a significant improvement in the properties of the all compositions. Besides, an improvement in the mechanical properties was attained with the addition of 4 phr of epoxidized soybean oil.

  6. ARA-aldehyde and ABA-trans-diol in apple fruits

    International Nuclear Information System (INIS)

    Rock, C.D.; Zeevaart, J.A.D.

    1989-01-01

    We have isolated ABA-aldehyde and ABA-t-diol from postharvest apple fruits, cv. Granny Smith and confirmed their structure by GC-MS. These putative ABA biosynthetic precursors incorporate 18 O to a similar degree as ABA during 48 hours under 18 O 2 atmospheres. The presence of significant amounts of ABA-aldehyde can explain the unique 18 O labeling pattern of ABA in this tissue, where a majority of ABA molecules containing 18 O is labeled in the 1'-hydroxyl group and not in the side chain carboxyl group, the primary site of incorporation for stressed leaves. Exchange of the carbonyl oxygen of ABA-aldehyde with water would decrease 18 O enrichment in the side chain. Results of 18 O 2 experiments and feeding studies using hexadeutero-ABA-aldehyde will be presented and the biosynthetic relationship of these compounds discussed

  7. [BMIM][PF(6)] promotes the synthesis of halohydrin esters from diols using potassium halides.

    Science.gov (United States)

    Oromí-Farrús, Mireia; Eras, Jordi; Villorbina, Gemma; Torres, Mercè; Llopis-Mestre, Veronica; Welton, Tom; Canela, Ramon

    2008-10-01

    Haloesterification of diverse diols with various carboxylic acids was achieved using potassium halides (KX) as the only halide source in ionic liquids. The best yield was obtained in [BMIM][PF(6)] when 1,2-octanediol, palmitic acid and KBr were used. This yield was 85% and the regioisomer with the bromine in primary position was present in a 75:25 ratio. The regioisomeric ratio could be improved using either KCl or some phenylcarboxylic acids. [BMIM][PF(6)] acts as both reaction media and catalyst of the reaction. To the best of our knowledge, this type of combined reaction using an ionic liquid is unprecedented. The other solvents tested did not lead either to the same yield or to the same regioisomeric ratio.

  8. Removal of pyrene and benzo(a)pyrene micropollutant from water via adsorption by green synthesized iron oxide nanoparticles

    Science.gov (United States)

    Hassan, Saad S. M.; Abdel-Shafy, Hussein I.; Mansour, Mona S. M.

    2018-03-01

    Polycyclic aromatic hydrocarbons (PAHs) in water are classified as organic micropollutants, which are carcinogenic even in very low concentration (ppb). In this study the green synthesized iron oxide nanoparticles (IONPs) were green synthesized at room temperature by using pomegranate peel extract. The green synthesized IONPs were used for adsorbing benzo(a)pyrene and pyrene (PAHs) from water. Factors affecting the adsorption were investigated. These factors are: nanoparticles dose, pH, temperature, and initial concentration of PAHs. The overall results showed that the maximum adsorption capacities of IONPs towards pyrene and benzo(a)pyrene were 2.8 and 0.029 mg g-1, respectively. The thermodynamic study indicated an exothermic adsorption process of pyrene and benzo(a)pyrene. The kinetic and isotherm studies were carried out. The obtained data revealed that the adsorption process follows a pseudo-second order mechanism and obeys Langmuir isotherm model. In addition, the IONPs proved to be a potential candidate for the adsorption of pyrene and benzo(a)pyrene even after five cycles of use and regeneration. The investigation was extended using semi-pilot plant to remove the studied PAHs from artificially contaminated water. The results showed that the IONPs was capable to remove the pyrene and benzo (a) pyrene at the rate of 98.5 and 99%, respectively. It also can be used as disinfectant.

  9. Benzo[a]pyrene co-metabolism in the presence of plant root extracts and exudates: Implications for phytoremediation

    Energy Technology Data Exchange (ETDEWEB)

    Rentz, Jeremy A [Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242 (United States); Alvarez, Pedro J.J. [Civil and Environmental Engineering, Rice University, Houston, TX 77251 (United States); Schnoor, Jerald L [Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242 (United States)

    2005-08-15

    Benzo[a]pyrene, a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) was removed from solution by Sphingomonas yanoikuyae JAR02 while growing on root products as a primary carbon and energy source. Plant root extracts of osage orange (Maclura pomifera), hybrid willow (Salix albaxmatsudana), or kou (Cordia subcordata), or plant root exudates of white mulberry (Morus alba) supported 15-20% benzo[a]pyrene removal over 24 h that was similar to a succinate grown culture and an unfed acetonitrile control. No differences were observed between the different root products tested. Mineralization of {sup 14}C-7-benzo[a]pyrene by S. yanoikuyae JAR02 yielded 0.2 to 0.3% {sup 14}CO{sub 2} when grown with plant root products. Collectively, these observations were consistent with field observations of enhanced phytoremediation of HMW PAH and corroborated the hypothesis that co-metabolism may be a plant/microbe interaction important to rhizoremediation. However, degradation and mineralization was much less for root product-exposed cultures than salicylate-induced cultures, and suggested the rhizosphere may not be an optimal environment for HMW PAH degradation by Sphingomonas yanoikuyae JAR02. - Bacterial benzo[a]pyrene cometabolism, a plant-microbe interaction affecting polycyclic aromatic hydrocarbon phytoremediation was demonstrated with Sphingomonas yanoikuyae JAR02 that utilized plant root extracts and exudates as primary substrates.

  10. Benzo[a]pyrene co-metabolism in the presence of plant root extracts and exudates: Implications for phytoremediation

    International Nuclear Information System (INIS)

    Rentz, Jeremy A.; Alvarez, Pedro J.J.; Schnoor, Jerald L.

    2005-01-01

    Benzo[a]pyrene, a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) was removed from solution by Sphingomonas yanoikuyae JAR02 while growing on root products as a primary carbon and energy source. Plant root extracts of osage orange (Maclura pomifera), hybrid willow (Salix albaxmatsudana), or kou (Cordia subcordata), or plant root exudates of white mulberry (Morus alba) supported 15-20% benzo[a]pyrene removal over 24 h that was similar to a succinate grown culture and an unfed acetonitrile control. No differences were observed between the different root products tested. Mineralization of 14 C-7-benzo[a]pyrene by S. yanoikuyae JAR02 yielded 0.2 to 0.3% 14 CO 2 when grown with plant root products. Collectively, these observations were consistent with field observations of enhanced phytoremediation of HMW PAH and corroborated the hypothesis that co-metabolism may be a plant/microbe interaction important to rhizoremediation. However, degradation and mineralization was much less for root product-exposed cultures than salicylate-induced cultures, and suggested the rhizosphere may not be an optimal environment for HMW PAH degradation by Sphingomonas yanoikuyae JAR02. - Bacterial benzo[a]pyrene cometabolism, a plant-microbe interaction affecting polycyclic aromatic hydrocarbon phytoremediation was demonstrated with Sphingomonas yanoikuyae JAR02 that utilized plant root extracts and exudates as primary substrates

  11. Soluble epoxide hydrolase in the generation and maintenance of high blood pressure in spontaneously hypertensive rats

    NARCIS (Netherlands)

    Koeners, Maarten P.; Wesseling, Sebastiaan; Ulu, Arzu; Lopez Sepulveda, Rocio; Morisseau, Christophe; Braam, Branko; Hammock, Bruce D.; Joles, Jaap A.

    Koeners MP, Wesseling S, Ulu A, Sepulveda RL, Morisseau C, Braam B, Hammock BD, Joles JA. Soluble epoxide hydrolase in the generation and maintenance of high blood pressure in spontaneously hypertensive rats. Am J Physiol Endocrinol Metab 300: E691-E698, 2011. First published January 25, 2011; doi:

  12. Chemoenzymatic epoxidation of alkenes with Candida antarctica lipase B and hydrogen peroxide in deep eutectic solvents

    NARCIS (Netherlands)

    Zhou, Pengfei; Wang, Xuping; Yang, Bo; Hollmann, F.; Wang, Yonghua

    2017-01-01

    Epoxides are important synthetic intermediates for the synthesis of a broad range of industrial products. This study presents a promising solution to the current limitation of enzyme instability. By using simple deep eutectic solvents such as choline chloride/sorbitol, significant stabilization

  13. Synthesis and Absolute Configuration of Enantiomerically Pure Vitamin K3 2,3-Epoxide

    NARCIS (Netherlands)

    Snatzke, Günther; Wijnberg, Hans; Feringa, Bernard; Marsman, Bea G.; Greydanus, Ben; Pluim, Henk

    1980-01-01

    The 2,3-epoxide of vitamin K3 (menadione, 1) has been prepared in enantiomerically pure form, and the absolute configuration has been deduced from the CD spectrum. The compound with the negative Cotton effect between 340 and 400 nm has the 2R,3S configuration.

  14. Salphen-Co(III) complexes catalyzed copolymerization of epoxides with CO2

    Czech Academy of Sciences Publication Activity Database

    Hošťálek, Z.; Mundil, R.; Císařová, I.; Trhlíková, Olga; Grau, E.; Peruch, F.; Cramail, H.; Merna, J.

    2015-01-01

    Roč. 63, 20 April (2015), s. 52-61 ISSN 0032-3861 Institutional support: RVO:61389013 Keywords : cobalt salphen catalyst * CO2 epoxide copolymerization * MALDI-TOF Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.586, year: 2015

  15. An efficient hybrid, nanostructured, epoxidation catalyst: titanium silsesquioxane-polystyrene copolymer supported on SBA-15

    NARCIS (Netherlands)

    Santen, van R.A.; Zhang, Lei; Abbenhuis, H.C.L.; Gerritsen, G.; Ní Bhriain, N.M.; Magusin, P.C.M.M.; Mezari, B.; Han, W.; Yang, Q.; Li, Can

    2007-01-01

    A novel interfacial hybrid epoxidation catalyst was designed with a new immobilization method for homogeneous catalysts by coating an inorganic support with an organic polymer film containing active sites. The titanium silsesquioxane (TiPOSS) complex, which contains a single-site titanium active

  16. An efficient hybrid, nanostructured, epoxidation catalyst: titanium silsesquioxane-polystyrene copolymer supported on SBA-15.

    Science.gov (United States)

    Zhang, Lei; Abbenhuis, Hendrikus C L; Gerritsen, Gijsbert; Bhriain, Nollaig Ní; Magusin, Pieter C M M; Mezari, Brahim; Han, Wei; van Santen, Rutger A; Yang, Qihua; Li, Can

    2007-01-01

    A novel interfacial hybrid epoxidation catalyst was designed with a new immobilization method for homogeneous catalysts by coating an inorganic support with an organic polymer film containing active sites. The titanium silsesquioxane (TiPOSS) complex, which contains a single-site titanium active center, was immobilized successfully by in-situ copolymerization on a mesoporous SBA-15-supported polystyrene polymer. The resulting hybrid materials exhibit attractive textural properties (highly ordered mesostructure, large specific surface area (>380 m2 g-1) and pore volume (>or==0.46 cm3 g-1)), and high activity in the epoxidation of alkenes. In the epoxidation of cyclooctene with tert-butyl hydrogen peroxide (TBHP), the hybrid catalysts have rate constants comparable with that of their homogeneous counterpart, and can be recycled at least seven times. They can also catalyze the epoxidation of cyclooctene with aqueous H2O2 as the oxidant. In two-phase reaction media, the catalysts show much higher activity than their homogeneous counterpart due to the hydrophobic environment around the active centers. They behave as interfacial catalysts due to their multifunctionality, that is, the hydrophobicity of polystyrene and the polyhedral oligomeric silsesquioxanes (POSS), and the hydrophilicity of the silica and the mesoporous structure. Combination of the immobilization of homogeneous catalysts on two conventional supports, inorganic solid and organic polymer, is demonstrated to achieve novel heterogeneous catalytic ensembles with the merits of attractive textural properties, tunable surface properties, and optimized environments around the active sites.

  17. Enhancement of catalyst performance in the direct propene epoxidation: a study into gold-titanium synergy

    NARCIS (Netherlands)

    Chen, J.; Halin, S.J.A.; Pidko, E.A.; Verhoeven, M.W.G.M.; Perez Ferrandez, D.M.; Hensen, E.J.M.; Schouten, J.C.; Nijhuis, T.A.

    2013-01-01

    Enhanced productivity toward propene oxide in the direct propene epoxidation with hydrogen and oxygen over gold nanoparticles supported on titanium-grafted silica was achieved by adjusting the gold–titanium synergy. Highly isolated titanium sites were obtained by lowering the titanium loading

  18. Synthesis and properties of cross-linked polymers from epoxidized rubber seed oil and triethylenetetramine

    NARCIS (Netherlands)

    Abduh, Muhammad Yusuf; Iqbal, Muhammad; Picchioni, Francesco; Manurung, Robert; Heeres, Hero J.

    2015-01-01

    A series of epoxidized oils were prepared from rubber seed, soybean, jatropha, palm, and coconut oils. The epoxy content varied from 0.03 to 7.4 wt %, in accordance with the degree of unsaturation of the oils (lowest for coconut, highest for rubber seed oil). Bulk polymerization/curing of the

  19. Synthesis of Chiral Cyclic Carbonates via Kinetic Resolution of Racemic Epoxides and Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Xiao Wu

    2016-01-01

    Full Text Available The catalytic synthesis of cyclic carbonates using carbon dioxide as a C1-building block is a highly active area of research. Here, we review the catalytic production of enantiomerically enriched cyclic carbonates via kinetic resolution of racemic epoxides catalysed by metal-containing catalyst systems.

  20. Epoxidation of Alkenes with Aqueous Hydrogen Peroxide and Quaternary Ammonium Bicarbonate Catalysts

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Kegnæs, Søren

    2013-01-01

    A range of solid and liquid catalysts containing bicarbonate anions were synthesised and tested for the epoxidation of alkenes with aqueous hydrogen peroxide. The combination of bicarbonate anions and quaternary ammonium cations opens up for new catalytic systems that can help to overcome...

  1. UTL titanosilicate: An extra-large pore epoxidation catalyst with tunable textural properties

    Czech Academy of Sciences Publication Activity Database

    Přech, Jan; Čejka, Jiří

    2016-01-01

    Roč. 277, č. 1 (2016), s. 2-8 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : titanosilicate UTL * top-down synthesis * epoxidation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.636, year: 2016

  2. Dinuclear ru-aqua complexes for selective epoxidation catalysis based on supramolecular substrate orientation effects

    KAUST Repository

    Di Giovanni, Carlo; Poater, Albert; Benet-Buchholz, Jordi; Cavallo, Luigi; Solà , Miquel; Llobet, Antoni A.

    2014-01-01

    Ru-aqua complex {[RuII(trpy)(H2O)] 2(μ-pyr-dc)}+ is a powerful epoxidation catalyst for a wide range of linear and cyclic alkenes. High turnover numbers (TNs), up to 17000, and turnover frequencies (TOF), up to 24120 h-1 (6.7 s -1), have been obtained using PhIO as oxidant. This species presents an outstanding stereospecificity for both cis and trans olefins towards the formation of their corresponding cis and trans epoxides. In addition, it shows different reactivity to cis and trans olefins due to a substrate orientation supramolecular effect transmitted by its ligand scaffold. This effect together with the impressive reaction rates are rationalized using electrochemical techniques and DFT calculations. A new Ru-aqua complex that behaves as a powerful epoxidation catalyst for a wide range of linear and cyclic alkenes is reported. High turnover numbers and frequencies are obtained by using PhIO as oxidant. The complex shows an outstanding stereospecificity for both cis and trans olefins towards the formation of their corresponding cis and trans epoxides (see figure). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Functionalization of multi-walled carbon nanotubes by epoxide ring-opening polymerization

    International Nuclear Information System (INIS)

    Jin Fanlong; Rhee, Kyong Yop; Park, Soo-Jin

    2011-01-01

    In this study, covalent functionalization of carbon nanotubes (CNTs) was accomplished by surface-initiated epoxide ring-opening polymerization. FT-IR spectra showed that polyether and epoxide group covalently attached to the sidewalls of CNTs. TGA results indicated that the polyether was successfully grown from the CNT surface, with the final products having a polymer weight percentage of ca. 14–74 wt%. The O/C ratio of CNTs increased significantly from 5.1% to 29.8% after surface functionalization of CNTs. SEM and TEM images of functionalized CNTs exhibited that the tubes were enwrapped by polymer chains with thickness of several nanometers, forming core–shell structures with CNTs at the center. - Graphical abstract: Functionalized CNTs were enwrapped by polymer chains with thickness of several nanometers, forming core–shell structures with CNTs at the center. Highlights: ► CNTs were functionalized by epoxide ring-opening polymerization. ► Polyether and epoxide group covalently attached to the sidewalls of CNTs. ► Functionalized CNTs have a polymer weight percentage of ca. 14–74 wt%. ► Functionalized CNTs were enwrapped by polymer chains with thickness of several nanometers.

  4. Crack resistance increasing in epoxide-rubber coatings of NPP room floors

    International Nuclear Information System (INIS)

    Khorenzhenko, V.I.

    1986-01-01

    Problems of crack resistance increasing in epoxide-rubber coatings for the floors are considered. Exploitation experience of the floors in the special rooms of NPP is given. Perspectivity of application of the compositions described as the building materials for nuclear power stations is pointed out

  5. Improvement of enantioselectivity by immobilized imprinting of epoxide hydrolase from Rhodotorula glutinis

    NARCIS (Netherlands)

    Kronenburg, N.A.E.; Bont, de J.A.M.; Fischer, L.

    2001-01-01

    The yeast Rhodotorula glutinis contains an enantioselective, membrane-associated epoxide hydrolase (EH). Partially purified EH was immobilized in a two-step procedure. In the first step, the proteins were derivatized with itaconic anhydride. In the second step, the derivatized proteins were

  6. Cloning and characterization of an epoxide hydrolase-encoding gene from Rhodotorula glutinis

    NARCIS (Netherlands)

    Visser, H.; Vreugdenhil, S.; Bont, de J.A.M.; Verdoes, J.C.

    2000-01-01

    We cloned and characterized the epoxide hydrolase gene, EPH1, from Rhodotorula glutinis. The EPH1 open reading frame of 1230 bp was interrupted by nine introns and encoded a polypeptide of 409 amino acids with a calculated molecular mass of 46.3 kDa. The amino acid sequence was similar to that of

  7. Synthesis of epoxidized cardanol and its antioxidative properties for vegetable oils and biodiesel

    Science.gov (United States)

    A novel antioxidant epoxidized cardanol (ECD), derived from cardanol, was synthesized and characterized by FT-IR, 1H-NMR and 13C-NMR. Oxidative stability of ECD used in vegetable oils and biodiesel was evaluated by pressurized differential scanning calorimetry (PDSC) and the Rancimat method, respect...

  8. (SalenMn(III Catalyzed Asymmetric Epoxidation Reactions by Hydrogen Peroxide in Water: A Green Protocol

    Directory of Open Access Journals (Sweden)

    Francesco Paolo Ballistreri

    2016-07-01

    Full Text Available Enantioselective epoxidation reactions of some chosen reactive alkenes by a chiral Mn(III salen catalyst were performed in H2O employing H2O2 as oxidant and diethyltetradecylamine N-oxide (AOE-14 as surfactant. This procedure represents an environmentally benign protocol which leads to e.e. values ranging from good to excellent (up to 95%.

  9. Dinuclear ru-aqua complexes for selective epoxidation catalysis based on supramolecular substrate orientation effects

    KAUST Repository

    Di Giovanni, Carlo

    2014-03-03

    Ru-aqua complex {[RuII(trpy)(H2O)] 2(μ-pyr-dc)}+ is a powerful epoxidation catalyst for a wide range of linear and cyclic alkenes. High turnover numbers (TNs), up to 17000, and turnover frequencies (TOF), up to 24120 h-1 (6.7 s -1), have been obtained using PhIO as oxidant. This species presents an outstanding stereospecificity for both cis and trans olefins towards the formation of their corresponding cis and trans epoxides. In addition, it shows different reactivity to cis and trans olefins due to a substrate orientation supramolecular effect transmitted by its ligand scaffold. This effect together with the impressive reaction rates are rationalized using electrochemical techniques and DFT calculations. A new Ru-aqua complex that behaves as a powerful epoxidation catalyst for a wide range of linear and cyclic alkenes is reported. High turnover numbers and frequencies are obtained by using PhIO as oxidant. The complex shows an outstanding stereospecificity for both cis and trans olefins towards the formation of their corresponding cis and trans epoxides (see figure). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Organo-bridged silsesquioxane titanates for heterogeneous catalytic epoxidation with aqueous hydrogen peroxide

    NARCIS (Netherlands)

    Wang, Y.M.; Magusin, P.C.M.M.; Santen, van R.A.; Abbenhuis, H.C.L.

    2007-01-01

    Organo-bridged silsesquioxane titanates for heterogeneous catalytic epoxidation with aqueous hydrogen peroxide were synthesized through the acid-catalyzed hydrolysis and co-condensation of organotrialkoxysilane monomers and a,¿-bis(trialkoxysilyl) alkane cross-linkers in ethanol–water solution, with

  11. The role of epoxide hydrolase Y113H gene variant in pancreatic diseases.

    NARCIS (Netherlands)

    Ockenga, J.; Strunck, S.; Post, C.; Schulz, H.U.; Halangk, J.; Pfutzer, R.H.; Lohr, M.; Oettle, H.; Kage, A.; Rosendahl, J.; Keim, V.; Drenth, J.P.H.; Jansen, J.B.M.J.; Lochs, H.; Witt, H.

    2009-01-01

    OBJECTIVES: Chronic pancreatitis (CP) and pancreatic adenocarcinoma (pCA) are associated with risk factors such as alcohol intake and tobacco smoking. Microsomal epoxide hydrolase (EPHX1) is a phase II detoxifying enzyme capable of tobacco-borne toxicant inactivation. We studied the role of the

  12. Strengths, Weaknesses, Opportunities and Threats: Computational Studies of Mn- and Fe-Catalyzed Epoxidations

    Directory of Open Access Journals (Sweden)

    Filipe Teixeira

    2016-12-01

    Full Text Available The importance of epoxides as synthetic intermediates in a number of highly added-value chemicals, as well as the search for novel and more sustainable chemical processes have brought considerable attention to the catalytic activity of manganese and iron complexes towards the epoxidation of alkenes using non-toxic terminal oxidants. Particular attention has been given to Mn(salen and Fe(porphyrin catalysts. While the former attain remarkable enantioselectivity towards the epoxidation of cis-alkenes, the latter also serve as an important model for the behavior of cytochrome P450, thus allowing the exploration of complex biological processes. In this review, a systematic survey of the bibliographical data for the theoretical studies on Mn- and Fe-catalyzed epoxidations is presented. The most interesting patterns and trends are reported and finally analyzed using an evaluation framework similar to the SWOT (Strengths, Weaknesses, Opportunities and Threats analysis performed in enterprise media, with the ultimate aim to provide an overview of current trends and areas for future exploration.

  13. Chlorophyll catalyse the photo-transformation of carcinogenic benzo[a]pyrene in water

    Science.gov (United States)

    Luo, Lijuan; Lai, Xueying; Chen, Baowei; Lin, Li; Fang, Ling; Tam, Nora F. Y.; Luan, Tiangang

    2015-01-01

    Algal blooms cause great damage to water quality and aquaculture. However, this study showed that dead algal cells and chlorophyll could accelerate the photo-transformation of benzo[a]pyrene (BaP), a ubiquitous and persistent pollutant with potently mutagenic and carcinogenic toxicities, under visible light irradiation. Chlorophyll was found to be the major active substance in dead algal cells, and generated a high level of singlet oxygen to catalyse the photo-transformation of BaP. According to various BaP metabolites formed, the degradation mechanism was proposed as that chlorophyll in dead algal cells photo-oxidized BaP to quinones via photocatalytic generation of singlet oxygen. The results provided a good insight into the role of chlorophyll in the photo-transformation of organic contaminants and could be a possible remediation strategy of organic pollutants in natural environment. PMID:26239357

  14. Combined effects of inhaled plutonium oxide and benzo[a]pyrene on lung carcinogenesis in rats

    International Nuclear Information System (INIS)

    Metivier, H.; Masse, R.; Wahrendorf, J.; Lafuma, J.

    1986-01-01

    This study describes the effect of two intratracheal instillations (5 mg each) of benzo[a]pyrene (BP) on lung carcinogenesis in rats that had previously inhaled three levels of 239 PuO 2 . The BP does not modify survival in the high-level 239 PuO 2 -exposed rats, but markedly reduces survival in the two other groups. Median survival time with BP alone is shorter (666 days) than for the control group (838 days). Tumor incidence was increased by BP exposure, and the tumors were usually fatal, whereas tumors observed after 239 PuO 2 inhalation alone were usually not fatal. Statistical analysis of these data poses a problem because of the need to compare incidental and fatal tumors. 22 refs., 5 figs., 7 tabs

  15. Determination of lead, zinc and benzo(a)pyrene in incineration flue gas

    International Nuclear Information System (INIS)

    Han Baohua; Gao Zhuqin; Guo Qian

    2003-01-01

    An analitical method was developed for the determination of lead(Pb), zinc(Zn) and benzo(a)pyrene (BaP) in flue gas of radwaste pyroysis incinerator, respectively using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and High Performance Liquid Chromatography (HPLC). The sample preparation and the influence of major components in back-ground were researched. Interference correction coefficient for Pb and Zn are given in this article. The recovery of Pb, Zn and BaP are all above 84.0% and the relative standard deviation (RSD) were 3.51% for Pb, 7.28% for Zn and 4.50% for BaP, respectively. It shows that this analytical method can meet the incineration processes. (authors)

  16. Benzo[a]pyrene in urban environments of eastern Moscow: pollution levels and critical loads

    Science.gov (United States)

    Kasimov, Nikolay S.; Kosheleva, Natalia E.; Nikiforova, Elena M.; Vlasov, Dmitry V.

    2017-02-01

    Polycyclic aromatic hydrocarbons (PAHs), particularly benzo[a]pyrene (BaP), are toxic compounds emitted from various anthropogenic sources. Understanding the BaP concentrations, dynamics and decomposition in soil is required to assess the critical loads of BaP in urban environments. This study is the first attempt to evaluate all major input and output components of benzo[a]pyrene (BaP) balance and to calculate the permissible load on the urban environment in different land-use zones in the Eastern district of Moscow. BaP contamination of the snow cover in the Eastern district of Moscow was related to daily BaP fallout from the atmosphere. In 2010, the mean content of the pollutant in the snow dust was 1942 ng g-1, whereas the average intensity of its fallout was 7.13 ng m-2 per day. Across the territory, BaP winter fallout intensities varied from 0.3 to 1100 ng m-2 per day. The average BaP content in the surface (0-10 cm) soil horizons was 409 ng g-1, which is 83 times higher than the local background value and 20 times higher than the maximum permissible concentration (MPC) accepted in Russia. The variations in soil and snow BaP concentrations among different land-use zones were examined. A significant contribution of BaP from the atmosphere to urban soils was identified. Based on the measurements of BaP atmospheric fallout and BaP reserves in the soils, the critical loads of BaP for the land-use zones in the Eastern district were calculated for different values of degradation intensity and different exposure times. It was established that at an annual degradation intensity of 1-10 %, ecologically safe BaP levels in the soils of all land-use zones, excluding the agricultural zone, will only be reached after many decades or centuries.

  17. Kinetics and mechanism of styrene epoxidation by chlorite: role of chlorine dioxide.

    Science.gov (United States)

    Leigh, Jessica K; Rajput, Jonathan; Richardson, David E

    2014-07-07

    An investigation of the kinetics and mechanism for epoxidation of styrene and para-substituted styrenes by chlorite at 25 °C in the pH range of 5-6 is described. The proposed mechanism in water and water/acetonitrile includes seven oxidation states of chlorine (-I, 0, I, II, III, IV, and V) to account for the observed kinetics and product distributions. The model provides an unusually detailed quantitative mechanism for the complex reactions that occur in mixtures of chlorine species and organic substrates, particularly when the strong oxidant chlorite is employed. Kinetic control of the reaction is achieved by the addition of chlorine dioxide to the reaction mixture, thereby eliminating a substantial induction period observed when chlorite is used alone. The epoxidation agent is identified as chlorine dioxide, which is continually formed by the reaction of chlorite with hypochlorous acid that results from ClO produced by the epoxidation reaction. The overall stoichiometry is the result of two competing chain reactions in which the reactive intermediate ClO reacts with either chlorine dioxide or chlorite ion to produce hypochlorous acid and chlorate or chloride, respectively. At high chlorite ion concentrations, HOCl is rapidly eliminated by reaction with chlorite, minimizing side reactions between HOCl and Cl2 with the starting material. Epoxide selectivity (>90% under optimal conditions) is accurately predicted by the kinetic model. The model rate constant for direct reaction of styrene with ClO2(aq) to produce epoxide is (1.16 ± 0.07) × 10(-2) M(-1) s(-1) for 60:40 water/acetonitrile with 0.20 M acetate buffer. Rate constants for para substituted styrenes (R = -SO3(-), -OMe, -Me, -Cl, -H, and -NO2) with ClO2 were determined. The results support the radical addition/elimination mechanism originally proposed by Kolar and Lindgren to account for the formation of styrene oxide in the reaction of styrene with chlorine dioxide.

  18. Pilot scale production, characterization, and optimization of epoxidized vegetable oil-based resins

    Science.gov (United States)

    Monono, Ewumbua Menyoli

    Novel epoxidized sucrose soyate (ESS) resins perform much better than other vegetable oil-based resins; thus, they are of current interest for commercial scale production and for a wide range of applications in coatings and polymeric materials. However, no work has been published that successfully scaled-up the reaction above a 1 kg batch size. To achieve this goal, canola oil was first epoxidized at a 300 g scale to study the epoxidation rate and thermal profile at different hydrogen peroxide (H2O2) addition rates, bath temperatures, and reaction times. At least 83% conversion of double bonds to oxirane was achieved by 2.5 h, and the reaction temperature was 8-15 °C higher than the water bath temperature within the first 30-40 min of epoxidation. A 38 L stainless steel kettle was modified as a reactor to produce 10 kg of ESS. Twenty 7-10 kg batches of ESS were produced with an overall 87.5% resin yield and > 98% conversion after batch three. The conversion and resin quality were consistent across the batches due to the modifications on the reaction that improved mixing and reaction temperature control within 55-65 oC. The total production time was reduced from 8 to 4 days due to the fabrication of a 40 L separatory funnel for both washing and filtration. A math model was developed to optimize the epoxidation process. This was done by using the Box-Behnken design to model the conversion at various acetic acid, H2O2, and Amberlite ratios and at various reaction temperatures and times. The model had an adjusted R2 of 97.6% and predicted R2 of 96.8%. The model showed that reagent amounts and time can be reduced by 18% without compromising the desired conversion value and quality.

  19. Synthesis and essay of an Ionomer like catalyst of olefins epoxidation

    International Nuclear Information System (INIS)

    Boyaca Mendivelso, Alejandro; Tempesti, Ezio

    1995-01-01

    The purpose of the present work is the preparation of an ionomer with base in Molybdenum and to evaluate its activity like catalyst of olefins epoxidation like alternative of synthesis of catalysts of the Hawk process. A polymer is synthesized with available functional groups to stabilize the metal starting from sodium molybdate; the characterization is made by atomic absorption, spectroscopy to GO, and X.P.S. The characterization indicates that indeed it is possible to stabilize the Mo in the main polymeric. The evaluation in reaction in liquid phase allows similar conversions to those of a homogeneous catalyst. The selective epoxidation of olefins for alkyl hydroperoxides, it has acquired great importance inside the industrial processes obtaining of propylene oxide due to the recent use of the terbutilic alcohol (co-produced together with the epoxide), as preservative in gasoline free of lead. In the environment of these processes, and in particular in the Hawk process possibilities of technological innovation, in the concerning to the heterogenization of conventional catalysts, at the moment used in homogeneous phase. The present work collaborate to some tentative that look for to generate alternative of preparation of catalysts for the process Hawk, synthesizing and testing the activity of an ionomer like epoxidation catalyst, which tries to reproduce the chemical structure of the complexes organ-metallic pear to suppress the separation stages and necessary recovery facilitating its recurrent reutilization with eventual economic repercussions in the industrial process. It is described the procedure of synthesis of the ionomer, the characterization and the evaluation of the activity in reaction under diverse conditions. Of the made characterization it comes off that the heterogenization of catalysts for olefins epoxidation, according to the Hawk process, is possible by means of the preparation of polymers modified appropriately. Likewise the evaluation in

  20. Long chain diol index (LDI) as an organic-based sea surface temperature proxy in the Korean East Sea (NW Pacific)

    Science.gov (United States)

    Gal, Jong-Ku; Kim, Jung-Hyun; Kang, Su-Jin; Lee, Dong-Hun; Shin, Kyung-Hoon

    2016-04-01

    Long chain diol index (LDI) was introduced as an organic-based sea surface temperature (SST) proxy. LDI is expressed as the C30 1,15-diol abundance relative to those of C28 1,13-, C30 1,13- and C30 1,15-diols. There were a few studies which accessed the potential of LDI based on the culture, core top sediments, suspended particulate organic matters, and down-core sediments. However it is still unknown about the source of the diols and robustness as the SST proxy in the various marine environments. In the current study, we examined the applicability of the LDI in the East Sea of Korea where productivity and thus sedimentation rates are high. We will compare the LDI data with those of alkenone-based UK'37 by analyzing two multicores covering the last 100 year.

  1. Preparation and characterization of fluorophenylboronic acid-functionalized affinity monolithic columns for the selective enrichment of cis-diol-containing biomolecules.

    Science.gov (United States)

    Li, Qianjin; Liu, Zhen

    2015-01-01

    Boronate affinity monolithic columns have been developed into an important means for the selective recognition and capture of cis-diol-containing biomolecules, such as glycoproteins, nucleosides and saccharides. The ligands of boronic acids are playing an important role in boronate affinity monolithic columns. Although several boronate affinity monoliths with high affinity toward cis-diol-containing biomolecules have been reported, only few publications are focused on their detailed procedures for preparation and characterization. This chapter describes in detail the preparation and characterization of a boronate affinity monolithic column applying 2,4-difluoro-3-formyl-phenylboronic acid (DFFPBA) as a ligand. The DFFPBA-functionalized monolithic column not only exhibited an ultrahigh boronate affinity toward cis-diol-containing biomolecules, but also showed great potential for the selective enrichment of cis-diol-containing biomolecules in real samples.

  2. QSPR models based on molecular mechanics and quantum chemical calculations. 1. Construction of Boltzmann averaged descriptors for alkanes, alcohols, diols, ethers and cyclic compounds

    DEFF Research Database (Denmark)

    Dyekjær, Jane Dannow; Rasmussen, Kjeld; Jonsdottir, Svava Osk

    2002-01-01

    Values for nine descriptors for QSPR (quantitative structure-property relationships) modeling of physical properties of 96 alkanes, alcohols, ethers, diols, triols and cyclic alkanes and alcohols in conjunction with the program Codessa are presented. The descriptors are Boltzmann-averaged by sele......Values for nine descriptors for QSPR (quantitative structure-property relationships) modeling of physical properties of 96 alkanes, alcohols, ethers, diols, triols and cyclic alkanes and alcohols in conjunction with the program Codessa are presented. The descriptors are Boltzmann...

  3. Cs2CO3-promoted polycondensation of CO2with diols and dihalides for the synthesis of miscellaneous polycarbonates

    KAUST Repository

    Chen, Zuliang

    2016-07-12

    A one-pot protocol for the direct synthesis of polycarbonates through polycondensation of diols, dihalides and CO2 in the presence of Cs2CO3 is described. The conditions were optimized by studying the polycondensation of CO2 with 1,4-phenylenedimethanol and 1,4-dibromobutane as model monomers. Then, diols and dihalides with different spacers between the reactive groups including aliphatic, aromatic and poly(ethylene glycol) were tested under optimal conditions. Miscellaneous polycarbonates exhibiting molar masses in the range of 43 000 g mol-1 (GPC) and conversion higher than 96% could be obtained. The proposed mechanism rules out the possibility of ether linkage formation during polycondensation and accounts for the creation of carbonate linkages in two different ways. The thermal properties of the synthesized polycarbonates were unveiled by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). © 2016 The Royal Society of Chemistry.

  4. Efficient Pd@MIL-101(Cr) hetero-catalysts for 2-butyne-1,4-diol hydrogenation exhibiting high selectivity

    KAUST Repository

    Yin, Dongdong

    2017-01-05

    Pd@MIL-101(Cr) hetero-catalysts have been successfully prepared using the metal-organic chemical vapour deposition (MOCVD) approach, by choosing [Pd(η-CH)(η-CH)] as a volatile precursor, and the hydrothermally stable metal-organic framework, MIL-101(Cr) as a support. The prepared Pd@MIL-101(Cr) hetero-catalysts characterized with various analytical techniques, exhibited highly monodispersed immobilized Pd nanoparticles in the MIL-101(Cr) cavities, while retaining the pristine crystallinity and porosity. The intact hybrid Pd@MIL-101(Cr) has been demonstrated to be an efficient catalyst for 2-butyne-1,4-diol hydrogenation with excellent activity, stability and selectivity (2-butene-1,4-diol (>94%)).

  5. Effects of the Amount and Type of Diol Ring Openers on the Properties of Oligolactide Acrylates for UV-Curable Printing Inks

    Directory of Open Access Journals (Sweden)

    Santi Kulsiriswad

    2017-10-01

    Full Text Available This study aimed to synthesize low viscosity oligolactide acrylates for UV-curable inks from oligolactide diols. Firstly, low molecular weight oligolactide diols were prepared by ring opening reaction of L-lactide with diols. Oligolactide acrylates were then synthesized by functionalizing the oligolactide diols with acrylic acid. In this study, three diol ring openers having short and long alkyl chain length were used to investigate the effects of the amount and type of diols on the properties of the oligolactide acrylates. The obtained oligomers were characterized, and the viscosities of oligolactide acrylates were measured. Results showed that oligolactide acrylates were successfully synthesized in all cases of ring openers, as confirmed by 1H-NMR (proton nuclear magnetic resonance spectroscopy and FTIR (Fourier transform infrared spectroscopy. An increase in the alkyl chain length of the ring openers resulted in oligomers with lower viscosity and a decrease in Tg. Following that, the obtained oligolactide acrylates were employed for the formulation of UV-curable screen printing inks and their properties were investigated. Results showed that the inks formulated from oligomers with lower molecular weight exhibited better ink flow. Additionally, all ink films cured by UV radiation were very flexible with excellent adhesion, high impact resistance, and excellent water resistance.

  6. Dielectric and ferroelectric sensing based on molecular recognition in Cu(1,10-phenlothroline)2SeO4.(diol) systems

    Science.gov (United States)

    Ye, Heng-Yun; Liao, Wei-Qiang; Zhou, Qionghua; Zhang, Yi; Wang, Jinlan; You, Yu-Meng; Wang, Jin-Yun; Chen, Zhong-Ning; Li, Peng-Fei; Fu, Da-Wei; Huang, Songping D.; Xiong, Ren-Gen

    2017-02-01

    The process of molecular recognition is the assembly of two or more molecules through weak interactions. Information in the process of molecular recognition can be transmitted to us via physical signals, which may find applications in sensing and switching. The conventional signals are mainly limited to light signal. Here, we describe the recognition of diols with Cu(1,10-phenlothroline)2SeO4 and the transduction of discrete recognition events into dielectric and/or ferroelectric signals. We observe that systems of Cu(1,10-phenlothroline)2SeO4.(diol) exhibit significant dielectric and/or ferroelectric dependence on different diol molecules. The compounds including ethane-1,2-diol or propane-1,2-diol just show small temperature-dependent dielectric anomalies and no reversible polarization, while the compound including ethane-1,3-diol shows giant temperature-dependent dielectric anomalies as well as ferroelectric reversible spontaneous polarization. This finding shows that dielectricity and/or ferroelectricity has the potential to be used for signalling molecular recognition.

  7. The reactivity of linseed and soybean oil with different epoxidation degree towards vinyl acetate and impact of the resulting copolymer on the wood durability

    Directory of Open Access Journals (Sweden)

    M. Jebrane

    2017-05-01

    Full Text Available Linseed (LO and soybean oil (SO were in–situ epoxidized with peracetic acid to produce different degree of epoxidized LO and epoxidized SO. For comparison purpose, commercial epoxidized linseed oil (ELO® and epoxidized soybean oil (ESO® were also included in the study. The effect of epoxidation degree on the copolymerization reaction between epoxidized oils and vinyl acetate (VAc was investigated. Results showed that a copolymer can be formed between VAc and epoxidized LO with high epoxy content, while no reaction occurred between VAc and SO or its epoxidized derivatives. As the most reactive monomer among the studied oils, the epoxidized LO with highest epoxy content (i.e. ELO® was mixed with VAc and then impregnated into the wood using three different ELO®/VAc formulations either as solution or as emulsions. After curing, the impact of the resulting copolymer issued from the three tested formulations on the wood durability was evaluated. Results showed that the formulation comprising VAc, ELO®, H2O, K2S2O8 and alkaline emulsifier (Formulation 3 can significantly improve wood’s durability against white rot- (Trametes versicolor and brown rot fungi (Postia placenta and Coniophora puteana. Treated wood of 8% weight percentage gain (WPG was sufficient to ensure decay resistance against the test fungi with less than 5% mass loss.

  8. Monolayer behaviour of chiral compounds at the air-water interface: 4-hexadecyloxy-butane-1,2-diol

    DEFF Research Database (Denmark)

    Rietz, R.; Rettig, W.; Brezesinski, G.

    1996-01-01

    Monolayers of the pure S-enantiomer (x(S) = 1) and of two mixtures x(S) = 0.75 and x(S) = 0.5 (racemate) of 4-hexadecyloxy-butane-1,2-diol (C16H33-O-CH2-CH2-CHOH-CH2OH) (HOBD) have been studied at the air-water interface by thermodynamic measurements, fluorescence microscopy and X-ray diffraction...

  9. A novel type of banana liquid crystals based on 1-substituted naphtalene-2,7-diol cores

    Czech Academy of Sciences Publication Activity Database

    Svoboda, J.; Novotná, Vladimíra; Kozmík, V.; Glogarová, Milada; Weissflog, W.; Diele, S.; Pelzl, G.

    2003-01-01

    Roč. 13, - (2003), s. 2104-2110 ISSN 0959-9428 R&D Projects: GA ČR(CZ) GA202/02/0840 Grant - others:COST(XE) D14 WG 00015 Institutional research plan: CEZ:AV0Z1010914 Keywords : liquid crystals * banana -shaped mesogens * substituted naphthalene diols Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.659, year: 2003

  10. One pot 'click' reactions : tandem enantioselective biocatalytic epoxide ring opening and [3+2] azide alkyne cycloaddition

    NARCIS (Netherlands)

    Campbell-Verduyn, Lachlan S.; Szymanski, Wiktor; Postema, Christiaan P.; Dierckx, Rudi A.; Elsinga, Philip H.; Janssen, Dick B.; Feringa, Ben L.

    2010-01-01

    Halohydrin dehalogenase (HheC) can perform enantioselective azidolysis of aromatic epoxides to 1,2-azido alcohols which are subsequently ligated to alkynes producing chiral hydroxy triazoles in a one-pot procedure with excellent enantiomeric excess.

  11. Identification and characterization of dimeric oxidation products of p-cymene-2,3-diol isolated from Thymus vulgaris L.

    Science.gov (United States)

    Rainis, Guido; Ternes, Waldemar

    2014-01-08

    The aim of this study was to investigate the oxidation products of p-cymene-2,3-diol, a major antioxidative constituent of thyme (Thymus vulgaris L.). Although a dimeric form of p-cymene-2,3-diol and some derivative substances exhibiting valuable food technological and health-promoting properties have been reported in earlier publications, no obvious correlation has been shown between these substances. A modified HPLC-ESI-MS method made it possible to prove that two dimers, 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl (1) and the newly identified 3',4'-dihydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl-3,4-dione (2), are oxidation products of p-cymene-2,3-diol. 2 was characterized by the fragmentation pattern determined by multiple mass spectrometry, (1)H NMR, (13)C NMR, H-H COSY, HSQC, and HMBC. Both biphenyls were also quantitated in freeze-dried thyme as well as in a food matrix spiked with thyme extract. Model experiments using raw and cooked minced pork meat as matrix and sodium nitrite as oxidizing and reduction agent with and without ascorbic acid as protective reagent showed the correlation between food processing and dimer generation.

  12. Aggressive electrolyte poisons and multifunctional fluids comprised of diols and diamines for emergency shutdown of lithium-ion batteries

    Science.gov (United States)

    Noelle, Daniel J.; Shi, Yang; Wang, Meng; Le, Anh V.; Qiao, Yu

    2018-04-01

    Electrolyte poisons comprised of diols and diamines are investigated for the intended function of exacerbating internal resistance in lithium-ion batteries upon short circuit failure, to quickly arrest uncontrolled joule heat generation in the earliest stages. The competing dynamics of powerful short circuit currents and electrolyte poisoning interactions are evaluated via simultaneous nail penetration and poison injection of LIR2450 format LiCoO2/graphite 120 mAh coin cells. To forcibly increase electrolyte impedance, diols serve to hinder charge-carrying ion mobility by raising solution viscosity, while diamines disrupt solvent permittivity by rapidly polymerizing the ethylene carbonate solvent. Diamines demonstrate great potency, and are suitable for integration into battery cells within chemically-inert, breakable containers, rigged for release upon mechanical activation. Mixtures of 1,2-ethanediol and 1,2-ethanediamine show synergistic poisoning effects, decreasing peak temperature accrued by 70% when introduced simultaneously upon nail penetration. With the innate presence and abundance of diols and diamines in electric vehicle heat exchangers, they may be employed for multifunctional applications.

  13. Life history traits and the activity of antioxidative enzymes in Lymantria dispar L. (lepidoptera, lymantriidae) larvae exposed to benzo[a]pyrene.

    Science.gov (United States)

    Ilijin, Larisa; Mrdaković, Marija; Todorović, Dajana; Vlahović, Milena; Gavrilović, Anja; Mrkonja, Aleksandra; Perić-Mataruga, Vesna

    2015-11-01

    Increased presence of benzo[a]pyrene in the environment underlines the need for development of sensitive biomarkers for monitoring. Antioxidative enzymes could be used as early-warning signals because of their sensitivity and applicability. The activity of 2 antioxidative enzymes, superoxide dismutase (SOD) and catalase (CAT), were measured in midgut tissues of fifth instar Lymantria dispar larvae exposed to different concentrations of benzo[a]pyrene: 2 ng, 10 ng, 20 ng, 100 ng, 200 ng, and 2000 ng benzo[a]pyrene/g dry food weight. Larval development, larval mass, and relative growth rate were also monitored. The authors detected prolonged larval development, as well as reduced larval mass and relative growth rate in larvae exposed to all benzo[a]pyrene concentrations. The L. dispar midgut SOD activity was significantly increased, and 2 SOD isoforms were detected on native polyacrylamide gel electrophoresis in larvae fed on artificial diet supplemented with benzo[a]pyrene. In contrast, the control group had only 1 isoform. Catalase activity was significantly increased in all benzo[a]pyrene-treated larvae. Native gel electrophoresis showed that a switch in active CAT isoforms occurred after benzo[a]pyrene treatment. Thus, SOD and CAT in polyphagous herbivorous L. dispar larvae are very sensitive to low concentrations of benzo[a]pyrene. Therefore, they could be used as biomarkers for exposure and effects of this toxic polycyclic aromatic hydrocarbon. © 2015 SETAC.

  14. Hasse diagram as a green analytical metrics tool: ranking of methods for benzo[a]pyrene determination in sediments.

    Science.gov (United States)

    Bigus, Paulina; Tsakovski, Stefan; Simeonov, Vasil; Namieśnik, Jacek; Tobiszewski, Marek

    2016-05-01

    This study presents an application of the Hasse diagram technique (HDT) as the assessment tool to select the most appropriate analytical procedures according to their greenness or the best analytical performance. The dataset consists of analytical procedures for benzo[a]pyrene determination in sediment samples, which were described by 11 variables concerning their greenness and analytical performance. Two analyses with the HDT were performed-the first one with metrological variables and the second one with "green" variables as input data. Both HDT analyses ranked different analytical procedures as the most valuable, suggesting that green analytical chemistry is not in accordance with metrology when benzo[a]pyrene in sediment samples is determined. The HDT can be used as a good decision support tool to choose the proper analytical procedure concerning green analytical chemistry principles and analytical performance merits.

  15. Novel approaches to analysis of 3-chloropropane-1,2-diol esters in vegetable oils.

    Science.gov (United States)

    Moravcova, Eliska; Vaclavik, Lukas; Lacina, Ondrej; Hrbek, Vojtech; Riddellova, Katerina; Hajslova, Jana

    2012-03-01

    A sensitive and accurate method utilizing ultrahigh performance liquid chromatography (U-HPLC) coupled to high resolution mass spectrometry based on orbitrap technology (orbitrapMS) for the analysis of nine 3-chloropropane-1,2-diol (3-MCPD) diesters in vegetable oils was developed. To remove the interfering triacylglycerols that induce strong matrix effects, a clean-up step on silica gel column was used. The quantitative analysis was performed with the use of deuterium-labeled internal standards. The lowest calibration levels estimated for the respective analytes ranged from 2 to 5 μg kg(-1). Good recovery values (89-120%) and repeatability (RSD 5-9%) was obtained at spiking levels of 2 and 10 mg kg(-1). As an alternative, a novel ambient desorption ionization technique, direct analysis in real time (DART), hyphenated with orbitrapMS, was employed for no separation, high-throughput, semi-quantitative screening of 3-MCPD diesters in samples obtained by chromatographic fractionation. Additionally, the levels of 3-MCPD diesters measured in reallife vegetable oil samples (palm oil, sunflower oil, rapeseed oil) using both methods are reported. Relatively good agreement of the data generated by U-HPLC-orbitrapMS and DART-orbitrapMS were observed. With regard to a low ionization yield achieved for 3-MCPD monoesters, the methods presented in this paper were not yet applicable for the analysis of these contaminants at the naturally occurring levels.

  16. Formation of monochloropropane-1,2-diol and its esters in biscuits during baking.

    Science.gov (United States)

    Mogol, Burçe Ataç; Pye, Céline; Anderson, Warwick; Crews, Colin; Gökmen, Vural

    2014-07-23

    The formation of free monochloropropane-1,2-diol (3-MCPD and 2-MCPD) and its esters (bound-MCPD) was investigated in biscuits baked with various time and temperature combinations. The effect of salt as a source of chloride on the formation of these processing contaminants was also determined. Kinetic examination of the data indicated that an increasing baking temperature led to an increase in the reaction rate constants for 3-MCPD, 2-MCPD, and bound-MCPD. The activation energies of formation of 3-MCPD and 2-MCPD were found to be 29 kJ mol(-1). Eliminating salt from the recipe decreased 3-MCPD and 2-MCPD formation rate constants in biscuits by 57.5 and 85.4%, respectively. In addition, there was no formation of bound-MCPD in biscuits during baking without salt. Therefore, lowering the thermal load or limiting the chloride concentration should be considered a means of reducing or eliminating the formation of these contaminants in biscuits. Different refined oils were also used in the recipe to test their effect on the occurrence of free MCPD and its esters in biscuits. Besides the baking process, the results also confirmed the role of refined oil in the final concentration of these contaminants in biscuits.

  17. Binding site for the adenosyl group of coenzyme B12 in diol dehydrase

    International Nuclear Information System (INIS)

    Toraya, T.

    1985-01-01

    The binding of cob(II)alamin (CblII) and 5'-deoxyadenosine to diol dehydrase was studied spectroscopically and with [U- 14 C]5'-deoxyadenosine. CblII was bound to this enzyme forming a tight 1:1 complex which was resistant to oxidation by O 2 even in the presence of CN-. An irreversible 1:1:1 ternary complex was formed between enzyme, CblII, and 5'-deoxyadenosine, when the enzyme was incubated first with the nucleoside and then with CblII. When this order of addition of the constituents was reversed, no 5'-deoxyadenosine was bound to the enzyme-CblII complex. Hydroxocobalamin could also bind to the enzyme together with the nucleoside, while other cob(III)alamins bearing a bulkier Co beta ligand displaced the nucleoside upon binding to the enzyme. The binding of [U- 14 C]5'-deoxyadenosine was strongly inhibited by unlabeled 5'-deoxy-ara-adenosine, 4',5'-anhydroadenosine, adenosine, adenine, and 5',8-cyclic adenosine, in this order, but not by 5'-deoxyuridine. These results constitute direct evidence for the presence of the binding site for the adenosyl group of adenosylcobalamin, which is spatially limited to and highly specific for adenine nucleosides. The binding of 5'-deoxyadenosine to the apoenzyme was reversible

  18. Urinary 5α-androstane-3α,17β-diol radioimmunoassay: a new clinical evaluation

    International Nuclear Information System (INIS)

    Wright, F.; Mowszowicz, I.; Mauvais-Jarvis, P.

    1978-01-01

    A rapid specific and reliable RIA for urinary 5α-androstane-3α, 17β-diol (Adiol) is described using chromatographical purification and a specific antibody. Values are reported under some physiological and pathological conditions in 179 individuals. In 43 normal adult men the mean (+- SD) urinary Adiol excretion was 193 +- 77 μg/24 h, and in 29 normal women it was 44 +- 23 μg/24 h. These values are significantly different (P < 0.01). In 49 hirsute women, urinary Adiol Excretion was elevated (137 +- 51 μg/24 h) and significantly different from this value in normal women (P < 0.01). The urinary Adiol excretion in 10 postmenopausal women was very low (< 5 μg/24 h). In normal adult subjects, the theoretical contribution to urinary Adiol of the major secreted androgens was calculated. Whereas dehydroisoandrosterone and dehydroisoandrosterone sulfate yield the same amount of urinary Adiol in both sexes, testosterone is the main precursor of Adiol in men and androstenedione is the main precursor in normal premenopausal and hirsute women. However, the amount of Adiol recovered in the 24-h urine depends not only on the secretion rate of androstenedione and testosterone but is also related to the testosterone 5α-reductase activity present in androgen target cells, especially in sexual skin

  19. Selective hydrodeoxygenation of cyclic vicinal diols to cyclic alcohols over tungsten oxide-palladium catalysts.

    Science.gov (United States)

    Amada, Yasushi; Ota, Nobuhiko; Tamura, Masazumi; Nakagawa, Yoshinao; Tomishige, Keiichi

    2014-08-01

    Hydrodeoxygenation of cyclic vicinal diols such as 1,4-anhydroerythritol was conducted over catalysts containing both a noble metal and a group 5-7 transition-metal oxide. The combination of Pd and WOx allowed the removal of one of the two OH groups selectively. 3-Hydroxytetrahydrofuran was obtained from 1,4-anhydroerythritol in 72 and 74% yield over WOx -Pd/C and WOx -Pd/ZrO2 , respectively. The WOx -Pd/ZrO2 catalyst was reusable without significant loss of activity if the catalyst was calcined as a method of regeneration. Characterization of WOx -Pd/C with temperature-programmed reduction, X-ray diffraction, and transmission electron microscopy/energy-dispersive X-ray spectroscopy suggested that Pd metal particles approximately 9 nm in size were formed on amorphous tungsten oxide particles. A reaction mechanism was proposed on the basis of kinetics, reaction results with tungsten oxides under an atmosphere of Ar, and density functional theory calculations. A tetravalent tungsten center (W(IV) ) was formed by reduction of WO3 with the Pd catalyst and H2 , and this center served as the reductant for partial hydrodeoxygenation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Exposure assessment of 3-monochloropropane-1, 2-diol esters from edible oils and fats in China.

    Science.gov (United States)

    Li, Chang; Nie, Shao-Ping; Zhou, Yong-Qiang; Xie, Ming-Yong

    2015-01-01

    3-monochoropropane-1, 2-diol (3-MCPD) esters from edible oils are considered to be a possible risk factor for adverse effects in human. In the present study, the exposure assessment of 3-MCPD esters to Chinese population was performed. A total of 143 edible oil and fat samples collected from Chinese markets were determined for the concentrations of 3-MCPD esters. The concentration data together with the data of fats consumed were analyzed by the point evaluation and probabilistic assessment for the exposure assessment. The point evaluation showed that the mean daily intake (DI) of 3-MCPD esters were lower than the value of provisional maximum tolerable daily intake (PMTDI) of 3-MCPD (2 µg/kg BW/d). The mean DI values in different age groups obtained from probabilistic assessment were similar to the results of the point evaluation. However, in high percentiles (95th, 97.5th, 99th), the DI values in all age groups were undesirably higher than the value of PMTDI. Overall, the children and adolescents exposed more to 3-MCPD esters than the adults. Uncertainty was also analyzed for the exposure assessment. Decreasing the level of 3-MCPD esters in edible oils and consuming less oil were top priority to minimize the risk of 3-MCPD esters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. HILIC separation and quantitation of water-soluble vitamins using diol column.

    Science.gov (United States)

    Karatapanis, Andreas E; Fiamegos, Yiannis C; Stalikas, Constantine D

    2009-04-01

    Hydrophilic interaction liquid-chromatography (HILIC) in conjunction with diode array detection has been applied for the separation of selected-water-soluble vitamins using an end-capped HILIC-diol column. Vitamins with significant biological importance, such as thiamine (B(1)), riboflavin (B(2)), nicotinic acid (B(3)), nicotinamide (B(3)), pyridoxine (B(6)), folic acid (B(9)), cyanocobalamin (B(12)) and ascorbic acid (vitamin C) were simultaneously separated. Chromatographic conditions including type and percentage of organic modifier in the mobile phase, pH, type and concentration of buffer salt and flow rate were investigated. ACN was shown to offer superior separation for the compounds tested as compared to methanol, isopropanol and THF. Isocratic separation and analysis were achieved for six vitamins (B(1), B(2), nicotinic acid/nicotinamide, B(6) and C) at ACN-H(2)O 90:10, containing ammonium acetate 10 mM, triethylamine 20 mM, pH 5.0, using a flow rate of 0.8 mL/min, while a gradient was necessary to resolve a mixture of all eight water-soluble vitamins. The HILIC method was validated and successfully applied to the analysis of a pharmaceutical formulation and an energy drink negating the need for time consuming clean-up steps.

  2. Toxicological assessment of 3-chloropropane-1,2-diol and glycidol fatty acid esters in food.

    Science.gov (United States)

    Bakhiya, Nadiya; Abraham, Klaus; Gürtler, Rainer; Appel, Klaus Erich; Lampen, Alfonso

    2011-04-01

    Fatty acid esters of 3-chloropropane-1,2-diol (3-MCPD) and glycidol are a newly identified class of food process contaminants. They are widespread in refined vegetable oils and fats and have been detected in vegetable fat-containing products, including infant formulas. There are no toxicological data available yet on the 3-MCPD and glycidol esters, and the primary toxicological concern is based on the potential release of 3-MCPD or glycidol from the parent esters by lipase-catalyzed hydrolysis in the gastrointestinal tract. Although 3-MCPD is assessed as a nongenotoxic carcinogen with a tolerable daily intake (TDI) of 2 μg/kg body weight (bw), glycidol is a known genotoxic carcinogen, which induces tumors in numerous organs of rodents. The initial exposure estimates, conducted by Federal Institute for Risk Assessment (BfR) under the assumption that 100% of the 3-MPCD and glycidol are released from their esters, revealed especially that infants being fed commercial infant formula could ingest harmful amounts of 3-MCPD and glycidol. However, the real oral bioavailability may be lower. As this gives rise for toxicological concern, the currently available toxicological data of 3-MCPD and glycidol and their esters are summarized in this review and discussed with regard to data gaps and further research needs. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. 3-Monochloropropane-1,2-diol fatty acid esters in commercial deep-fat fried foods.

    Science.gov (United States)

    Arisseto, Adriana Pavesi; Marcolino, Priscila Francisca Corrêa; Vicente, Eduardo

    2015-01-01

    Levels of 3-monochloropropane-1,2-diol (3-MCPD) fatty acid esters were evaluated in commercial deep-fat fried foods from the Brazilian market using a GC-MS method preceded by acid-catalysed methanolysis. A limit of detection of 0.04 mg kg(-1), a limit of quantitation of 0.08 mg kg(-1), mean recoveries varying from 82% to 92%, and coefficients of variation ranging from 2.5% to 5.0% for repeatability and from 3.6% to 6.5% for within-laboratory reproducibility were obtained during in-house validation. The levels of the compounds in the evaluated samples, expressed as free 3-MCPD equivalent, ranged from not detected to 0.99 mg kg(-)(1), and the highest concentrations were observed in samples of chopped onion and garlic. A preliminary estimation of 3-MCPD intake using these occurrence data suggested low risks to human health, but a potential concern may arise in particular cases of consumers of fried food.

  4. [Occurrence of 3-monochloropropane-1,2-diol (3-MCPD) in food products].

    Science.gov (United States)

    Gawarska, Halina; Sawilska-Rautenstrauch, Dorota; Starski, Andrzej; Karłowski, Kazimierz

    2009-01-01

    3-Monochloropropane-1,2-diol (3-MCPD) is a contaminant belongs to a group of chemicals called chloropropanols. 3-MCPD can be formed in foods as result of processing or storage condition. At the beginning 3-MCPD was identified as a contaminant of the acid-hydrolysed vegetable protein, which is produced using hydrochloric acid and high temperature. Studies have shown that 3-MCPD is carcinogenic for rats, however genotoxic adverse effect was not observed in vivo. The purpose of this studies was determination of 3-MCPD amounts in retail food products and comparison with the EC legislative limit. 99 samples of foodstuffs was tested: soya sauce, hydrolysed vegetable protein (HVP), sugar, instant soups, stock cubes, bakery products, chips and edible fats. 3-MCPD was detected at levels below 10 microg/kg in 15% of the tested samples, and above 10 microg/kg in 63%. 3-MCPD was not occurred in 22% of the tested samples. The samples were analysed by gas chromatography-mass spectrometry (GC/MS).

  5. Antioxidants Inhibit Formation of 3-Monochloropropane-1,2-diol Esters in Model Reactions.

    Science.gov (United States)

    Li, Chang; Jia, Hanbing; Shen, Mingyue; Wang, Yuting; Nie, Shaoping; Chen, Yi; Zhou, Yongqiang; Wang, Yuanxing; Xie, Mingyong

    2015-11-11

    The capacities of six antioxidants to inhibit the formation of 3-monochloropropane-1,2 diol (3-MCPD) esters were examined in this study. Inhibitory capacities of the antioxidants were investigated both in chemical models containing the precursors (tripalmitoyl glycerol, 1,2-dipalmitoyl-sn-glycerol, monopalmitoyl glycerol, and sodium chloride) of 3-MCPD esters and in oil models (rapeseed oil and sodium chloride). Six antioxidants, butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA), tert-butyl hydroquinone (TBHQ), propyl gallate (PG), L-ascorbyl palmitate (AP), and α-tocopherol (VE), were found to exhibit inhibiting capacities on 3-MCPD ester formation both in chemical models and in oil models. TBHQ provided the highest inhibitory capacity both in chemical models and in oil models; 44% of 3-MCPD ester formation was inhibited in the presence of TBHQ (66 mg/kg of oil) after heating of rapeseed oil at 230 °C for 30 min, followed by PG and AP. BHT, BHA, and VE appeared to have weaker inhibitory abilities in both models. VE exhibited the lowest inhibition rate; 22% of 3-MCPD esters were inhibited in the presence of VE (172 mg/kg of oil) after heating of rapeseed oil at 230 °C for 30 min. In addition, the inhibition rates of PG and VE decreased dramatically with an increase in temperature or heating time. The results suggested that some antioxidants, such as TBHQ, PG, and AP, could be the potential inhibitors of 3-MCPD esters in practice.

  6. Influence of dough ingredients on 3-chloropropane-1,2-diol (3-MCPD) formation in toast.

    Science.gov (United States)

    Breitling-Utzmann, C M; Hrenn, H; Haase, N U; Unbehend, G M

    2005-02-01

    The influence of different dough ingredients such as fat, salt, sourdough, emulsifiers, and sugar on the formation of 3-chloropropane-1,2-diol (3-MCPD) during toast preparation under domestic conditions was investigated. In comparison with a fat-free recipe, addition of 1% peanut fat considerably increased 3-MCPD formation, but varying the fat (2-5%) or salt (1.6-2.4%) contents within technological acceptable limits did not show any significant differences. A baking agent, which is usually commercially applied by many toast bakers or industrial toast manufacturers, increased 3-MCPD formation in toasted bread slices. Considerable evidence was found that the baking agent's main component sucrose had the major part in increasing 3-MCPD levels. Emulsifiers containing monoacylglycerols moderately increased 3-MCPD levels, but the addition of lecithin did not have any significant influence. 3-MCPD levels showed a good correlation with the lightness (L* value) of the bread slices; their 3-MCPD content increased exponentially towards dark coloured toasts. The relation between 3-MCPD and 2-MCPD was an average of 3:1 in all samples. Dichloropropanols such as, for example, 1,3-dichloropropanol could not be detected.

  7. Defect Stabilized Gold Atoms on Graphene as Potential Catalysts for Ethylene Epoxidation: A First-principles Investigation

    KAUST Repository

    Liu, Xin; Yang, Yang; Chu, Minmin; Duan, Ting; Meng, Changgong; Han, Yu

    2015-01-01

    We performed a first-principles based investigation on the potential role of Au atoms stabilized by defects on graphene in ethylene epoxidation. We showed that the interactions between the Au atoms and vacancies on graphene not only make the Au atomic diffusion a 2.10 eV endothermic process, but also tune the energy level of Au-d states for the activation of O2 and ethylene and promote the formation and dissociation of the peroxametallacycle intermediate. The catalytic cycle of ethylene epoxidation is initiated with the formation of a peroxametallacycle intermediate by the coadsorbed ethylene and O2, through the dissociation of which an ethylene epoxide molecule and an adsorbed O atom are formed. Then, gaseous ethylene reacts with the remnant O atom directly for the formation of another ethylene epoxide molecule. The desorption of ethylene epoxide is facilitated by the subsequent adsorption of O2 or ethylene and a new reaction cycle initiates. The calculated energy barriers for the formation and dissociation of the peroxametallacycle intermediate and the regeneration of Au sites are 0.30, 0.84 and 0.18 eV, respectively, and are significantly lower than those for aldehyde formation. These findings suggest the potential high catalytic performance of these Au atoms for ethylene epoxidation.

  8. Defect Stabilized Gold Atoms on Graphene as Potential Catalysts for Ethylene Epoxidation: A First-principles Investigation

    KAUST Repository

    Liu, Xin

    2015-11-24

    We performed a first-principles based investigation on the potential role of Au atoms stabilized by defects on graphene in ethylene epoxidation. We showed that the interactions between the Au atoms and vacancies on graphene not only make the Au atomic diffusion a 2.10 eV endothermic process, but also tune the energy level of Au-d states for the activation of O2 and ethylene and promote the formation and dissociation of the peroxametallacycle intermediate. The catalytic cycle of ethylene epoxidation is initiated with the formation of a peroxametallacycle intermediate by the coadsorbed ethylene and O2, through the dissociation of which an ethylene epoxide molecule and an adsorbed O atom are formed. Then, gaseous ethylene reacts with the remnant O atom directly for the formation of another ethylene epoxide molecule. The desorption of ethylene epoxide is facilitated by the subsequent adsorption of O2 or ethylene and a new reaction cycle initiates. The calculated energy barriers for the formation and dissociation of the peroxametallacycle intermediate and the regeneration of Au sites are 0.30, 0.84 and 0.18 eV, respectively, and are significantly lower than those for aldehyde formation. These findings suggest the potential high catalytic performance of these Au atoms for ethylene epoxidation.

  9. Phthalic acid and benzo[a]pyrene in soil-plant-water systems amended with contaminated sewage sludge

    DEFF Research Database (Denmark)

    Mougin, C.; Dappozze, F.; Brault, A.

    2006-01-01

    We studied the fate of C-14-labelled phthalic acid and benzo[a]pyrene applied to the soil by the way of contaminated sewage sludge in model ecosystems allowing the simultaneous assessment of physicochemical and biological descriptors. Here we show that the mineralisation of phthalic acid is highe......[a]pyrene is recalcitrant to biodegradation whatever the type of soil contamination. We show also that the chemicals present in the sludge are poorly transferred to soil leachates and plant seedlings....

  10. A rat organo-typic model for identifying and characterizing Ρ53 mutations induced by benzo(a)pyrene treatment

    International Nuclear Information System (INIS)

    Le Rhun, Y.; Duthu, A.; May, E.; Paris, F.; Martin, M.

    1997-01-01

    A p53 wild-type cell line was established from embryo rat lung treated by the benzo(a)pyrene. Two different p53 mutant cell lines were derived from this parental cell line and showed different characteristics including tumor induction, radiosensitivity and chemo-sensitivity. This system is a useful tools for analysing the effect of various p53 mutants in neoplastic development. (authors)

  11. Synthesis and characterization of new magnetically recoverable molybdenum nanocatalyst for epoxidation of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Masteri-Farahani, M., E-mail: mfarahany@yahoo.com [Faculty of Chemistry, University of Tarbiat Moallem, Tehran (Iran, Islamic Republic of); Kashef, Z. [Faculty of Chemistry, University of Tarbiat Moallem, Tehran (Iran, Islamic Republic of)

    2012-04-15

    New heterogeneous molybdenum catalyst was prepared through covalent attachment of a Schiff base ligand on the surface of silica coated magnetite nanoparticles via aminopropyl spacer and subsequent complexation with MoO{sub 2}(acac){sub 2}. The prepared nanocatalyst was characterized with Fourier transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopies and vibrating sample magnetometry. Catalytic epoxidation of some olefins and allylic alcohols by prepared nanocatalyst using tert-butyl hydroperoxide and cumene hydroperoxide as oxidants was achieved with good activities and selectivities. - Highlights: Black-Right-Pointing-Pointer Silica coated magnetite nanoparticles were modified with a Schiff base ligand. Black-Right-Pointing-Pointer Next reaction with MoO{sub 2}(acac){sub 2} afforded magnetically recoverable nanocatalyst. Black-Right-Pointing-Pointer The prepared nanocatalyst catalyzed the epoxidation of olefins with TBHP.

  12. An investigation into the Ti-grafting structure on MCM-41 and epoxidation catalysis

    DEFF Research Database (Denmark)

    Yuan, Q.C.; Hagen, A.; Roessner, F.

    2006-01-01

    The structure of titanium species grafted on a purely siliceous MCM-41 and their catalysis in the epoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP) were investigated. FT-IR, XANES and UV-vis were used for the examination of the Ti-grafted MCM-41. The results indicated...... that the titanium atoms are grafted on the wall surface of the MCM-41 by four-fold coordination. The four-fold coordinated titanium species are mainly grafted by two or one -O-Si-O- bridges on the MCM-41, resulting in so-called bipodal or monopodal titanium centres in partially polymerised states. The ratio...... of monopodal to bipodal titanium increases with the increase in Ti-content. These partially polymerised titanium species considered as catalytic active centres have high activity and selectivity in the epoxidation reaction. The used Ti-grafted MCM-41 samples were regenerated by heating in nitrogen or air...

  13. Discovery and characterization of thermophilic limonene-1,2-epoxide hydrolases from hot spring metagenomic libraries

    DEFF Research Database (Denmark)

    Ferrandi, Erica Elisa; Sayer, Christopher; Isupov, Michail N.

    2015-01-01

    thermophilic sources, have higher optimal temperatures and apparent melting temperatures than Re-LEH. The new LEH enzymes have been crystallized and their structures solved to high resolution in the native form and in complex with the inhibitor valpromide for Tomsk-LEH and poly(ethylene glycol) for CH55-LEH......,2-epoxide hydrolase (LEH) family of enzymes. These two LEHs (Tomsk-LEH and CH55-LEH) show EH activities towards different epoxide substrates, differing in most cases from those previously identified for Rhodococcus erythropolis (Re-LEH) in terms of stereoselectivity. Tomsk-LEH and CH55-LEH, both from....... The structural analysis has provided insights into the LEH mechanism, substrate specificity and stereoselectivity of these new LEH enzymes, which has been supported by mutagenesis studies....

  14. Exploiting epoxidized natural rubber latex (ENRL) as a starting raw material for latex-based products

    Science.gov (United States)

    Siti Nor Qamarina, M.; Fatimah Rubaizah, M. R.; Nurul Suhaira, A.; Norhanifah, M. Y.

    2017-12-01

    Epoxidized natural rubber latex (ENRL) is a chemically modified natural rubber latex produced from epoxidation process that involves usage of organic peracids. Conversion of the ENRL into dry rubber products has been known to exhibit many beneficial properties, however limited published works were found on diversifiying the ENRL latex-based products applications. In this preliminary work, different source of raw materials and neutralization systems were investigated. The objective was to explore possibilities in producing distinctive ENRL. Findings have demonstrated that different source of raw materials and neutralization systems influenced the typical ENRL specifications, stability behavior and particle size distribution. Morphological observations performed on these ENRL systems appeared to agree with the ENRL characteristics achieved. Since experimenting these two main factors resulted in encouraging ENRL findings, detailed work shall be further scrutinized to search for an optimum condition in producing marketable ENRL specifically for latex-based products applications.

  15. Flow cytometric analysis of mitotic cycle perturbation by chemical carcinogens in cultured epithelial cells. [Effects of benzo(a)pyrene-diol-epoxide on mitotic cycle of cultural mouse liver epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Pearlman, Andrew Leonard [Univ. of California, Berkeley, CA (United States)

    1978-08-01

    A system for kinetic analysis of mitotic cycle perturbation by various agents was developed and applied to the study of the mitotic cycle effects and dependency of the chemical carcinogen benzo(a)pyrene-diolepoxide, DE, upon a mouse lever epithelial cell line, NMuLi. The study suggests that the targets of DE action are not confined to DNA alone but may include cytoplasmic structures as well. DE was found to affect cells located in virtually every phase of the mitotic cycle, with cells that were actively synthesizing DNA showing the strongest response. However, the resulting perturbations were not confined to S-phase alone. DE slowed traversal through S-phase by about 40% regardless of the cycle phase of the cells exposed to it, and slowed traversal through G2M by about 50%. When added to G1 cells, DE delayed recruitment of apparently quiescent (G0) cells by 2 hours, and reduced the synchrony of the cohort of cells recruited into active proliferation. The kinetic analysis system consists of four elements: tissue culture methods for propagating and harvesting cell populations; an elutriation centrifugation system for bulk synchronization of cells in various phases of the mitotic cycle; a flow cytometer (FCM), coupled with appropriate staining protocols, to enable rapid analysis of the DNA distribution of any given cell population; and data reduction and analysis methods for extracting information from the DNA histograms produced by the FCM. The elements of the system are discussed. A mathematical analysis of DNA histograms obtained by FCM is presented. The analysis leads to the detailed implementation of a new modeling approach. The new modeling approach is applied to the estimation of cell cycle kinetic parameters from time series of DNA histograms, and methods for the reduction and interpretation of such series are suggested.

  16. Stabilizing effect of epoxidized sunflower oil as a secondary stabilizer for Ca/Hg stabilized PVC

    Directory of Open Access Journals (Sweden)

    2008-01-01

    Full Text Available Unsaturated triglyceride oil sunflower was epoxidized and characterized by chemical and spectroscopic methods. Epoxidized sunflower oil (ESO was used as an organic thermal co-stabilizer for rigid poly(vinyl chloride (PVC in the presence of tricalcium dicitrate (Ca3(C6H5O72 and mercury (II acetate (Hg(CH3COO2. The thermo-oxidative degradation of PVC was studied in the presence of these ternary stabilizer systems at 170, 180, 190 and 200°C in N2 atmosphere. The effects of metal carboxylate combination Ca/Hg in the absence and in the presence of epoxidized sunflower oil on static heat treatment of PVC have been studied. The formation of polyene sequences was investigated by UV-visible and FT-IR spectroscopy and by comparing viscosity data obtained in the presence and in the absence of the additives. It was found that the additives retard the rate of degradation and reduce the extent of polymer chain scission associated with the thermal degradation of poly(vinyl chloride. Synergistic effects were found when stabilizer was blended in 50:50 weight ratios with either. It was found that ESO exerted a stabilizing effect on the degradation of PVC. The activation energy for degraded PVC in absence of stabilizers was 38.6 kJ•mol–1 and in the presence of Ca/Hg and Ca/Hg/ESO were 53.3 and 64.7 kJ•mol–1 respectively. In order of compare the efficiency of the epoxidized sunflower oil with these metal soap stabilizers, thermal stabilities were evaluated on the basis of evolved hydrogen chloride determined by conductometry technique and degree of discoloration are discussed.

  17. Supported sub-nanometer Ta oxide clusters as model catalysts for the selective epoxidation of cyclooctene

    KAUST Repository

    Zwaschka, Gregor; Rondelli, Manuel; Krause, Maximilian; Rö tzer, Marian David; Hedhili, Mohamed N.; Heiz, Ulrich; Basset, Jean-Marie; Schweinberger, Florian; D'Elia, Valerio

    2018-01-01

    The preparation of organic ligands-free, isolated tantalum oxide atoms (Ta1) and small clusters (Tan>1) on flat silicate supports was accomplished by ultra-high vacuum (UHV) techniques followed by oxidation in air. The resulting surface complexes were thoroughly characterized and tested as supported catalysts for the epoxidation of cycloalkenes. The observed catalytic performance highlights the potential of the applied method for the production of active catalysts and the study of well-defined, ligand-free metal oxide moieties.

  18. Supported sub-nanometer Ta oxide clusters as model catalysts for the selective epoxidation of cyclooctene

    KAUST Repository

    Zwaschka, Gregor

    2018-01-22

    The preparation of organic ligands-free, isolated tantalum oxide atoms (Ta1) and small clusters (Tan>1) on flat silicate supports was accomplished by ultra-high vacuum (UHV) techniques followed by oxidation in air. The resulting surface complexes were thoroughly characterized and tested as supported catalysts for the epoxidation of cycloalkenes. The observed catalytic performance highlights the potential of the applied method for the production of active catalysts and the study of well-defined, ligand-free metal oxide moieties.

  19. The stability of the three transmembrane and the four transmembrane human vitamin K epoxide reductase models

    Science.gov (United States)

    Wu, Sangwook

    2016-04-01

    The three transmembrane and the four transmembrane helix models are suggested for human vitamin K epoxide reductase (VKOR). In this study, we investigate the stability of the human three transmembrane/four transmembrane VKOR models by employing a coarse-grained normal mode analysis and molecular dynamics simulation. Based on the analysis of the mobility of each transmembrane domain, we suggest that the three transmembrane human VKOR model is more stable than the four transmembrane human VKOR model.

  20. Abscisic (ABA)-aldehyde is a precursor to, and 1',4'-trans-ABA-diol a catabolite of, ABA in apple

    International Nuclear Information System (INIS)

    Rock, C.D.; Zeevaart, J.A.D.

    1990-01-01

    Previous 18 O labeling studies of abscisic acid (ABA) have shown that apple (Malus domestica Borkh. cv Granny Smith) fruits synthesize a majority of [ 18 O]ABA with the label incorporated in the 1'-hydroxyl position and unlabeled in the carboxyl group (JAD Zeevaart, TG Heath, DA Gage [1989] Plant Physiol 91: 1594-1601). It was proposed that exchange of 18 O in the side chain with the medium occurred at an aldehyde intermediate stage of ABA biosynthesis. We have isolated ABA-aldehyde and 1'-4'-trans-ABA-diol (ABA-trans-diol) from 18 O-labeled apple fruit tissue and measured the extent and position of 18 O incorporation by tandem mass spectrometry. 18 O-Labeling patterns of ABA-aldehyde, ABA-trans-diol, and ABA indicate that ABA-aldehyde is a precursor to, and ABA-trans-diol a catabolite of, ABA. Exchange of 18 O in the carbonyl of ABA-aldehyde can be the cause of loss of 18 O from the side chain of [ 18 O]ABA. Results of feeding experiments with deuterated substrates provide further support for the precursor-product relationship of ABA-aldehyde → ABA → ABA-trans-diol. The ABA-aldehyde and ABA-trans-diol contents of fruits and leaves were low, approximately 1 and 0.02 nanograms per gram fresh weight for ABA-aldehyde and ABA-trans-diol, respectively, while ABA levels in fruits ranged from 10 to 200 nanograms per gram fresh weight. ABA biosynthesis was about 10-fold lower in fruits than in leaves. In fruits, the majority of ABA was conjugated to β-D-glucopyranosyl abscisate, whereas in leaves ABA was mainly hydroxylated to phaseic acid. Parallel pathways for ABA and trans-ABA biosynthesis and conjugation in fruits and leaves are proposed

  1. Characterization of an epoxide hydrolase from the Florida red tide dinoflagellate, Karenia brevis.

    Science.gov (United States)

    Sun, Pengfei; Leeson, Cristian; Zhi, Xiaoduo; Leng, Fenfei; Pierce, Richard H; Henry, Michael S; Rein, Kathleen S

    2016-02-01

    Epoxide hydrolases (EH, EC 3.3.2.3) have been proposed to be key enzymes in the biosynthesis of polyether (PE) ladder compounds such as the brevetoxins which are produced by the dinoflagellate Karenia brevis. These enzymes have the potential to catalyze kinetically disfavored endo-tet cyclization reactions. Data mining of K. brevis transcriptome libraries revealed two classes of epoxide hydrolases: microsomal and leukotriene A4 (LTA4) hydrolases. A microsomal EH was cloned and expressed for characterization. The enzyme is a monomeric protein with molecular weight 44kDa. Kinetic parameters were evaluated using a variety of epoxide substrates to assess substrate selectivity and enantioselectivity, as well as its potential to catalyze the critical endo-tet cyclization of epoxy alcohols. Monitoring of EH activity in high and low toxin producing cultures of K. brevis over a three week period showed consistently higher activity in the high toxin producing culture implicating the involvement of one or more EH in brevetoxin biosynthesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Persistence and changes in bioavailability of dieldrin, DDE and heptachlor epoxide in earthworms over 45 years

    Science.gov (United States)

    Beyer, W. Nelson; Gale, Robert W.

    2013-01-01

    The finding of dieldrin (88 ng/g), DDE (52 ng/g), and heptachlor epoxide (19 ng/g) in earthworms from experimental plots after a single moderate application (9 kg/ha) 45 years earlier attests to the remarkable persistence of these compounds in soil and their continued uptake by soil organisms. Half-lives (with 95 % confidence intervals) in earthworms, estimated from exponential decay equations, were as follows: dieldrin 4.9 (4.3-5.7) years, DDE 5.3 (4.7-6.1) years, and heptachlor epoxide 4.3 (3.8-4.9) years. These half-lives were not significantly different from those estimated after 20 years. Concentration factors (dry weight earthworm tissue/dry weight soil) were initially high and decreased mainly during the first 11 years after application. By the end of the study, average concentration factors were 1.5 (dieldrin), 4.0 (DDE), and 1.8 (heptachlor epoxide), respectively.

  3. Optimization of the In Situ Epoxidation of Linoleic Acid of Jatropha Curcas Oil With Performic Acid

    International Nuclear Information System (INIS)

    Hong, L.K.; Rahimi Mohd Yusop; Nadia Salih; Jumat Salimon

    2015-01-01

    The aim of this study is to optimise the epoxidation of linoleic acid of Jatropha curcas oil. This experiment was carried out with performic acid generated in situ by using hydrogen peroxide and formic acid. The method was evaluated on different parameters such as reaction temperature, mole ratios of formic acid to ethylenic unsaturation and hydrogen peroxide to ethylenic unsaturation. The optimum relative conversion into oxirane (80.4 %) and conversion of iodine (94.7 %) was achieved with ∼70 % yield at the condition of 45 degree Celsius reaction temperature, formic acid to ethylenic unsaturation mole ratio of 2.0, hydrogen peroxide to ethylenic unsaturation mole ratio of 12.0 for 2 hours of reaction time. The epoxidized linoleic acid was characterized by using Fourier transform infrared (FTIR) spectroscopy and NMR analysis. The result was also found that the formations of an epoxide and oxirane ring cleavage were both occurred at the same time if low amount of hydrogen peroxide was used. (author)

  4. Effects of partial hydrogenation, epoxidation, and hydroxylation on the fuel properties of fatty acid methyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Wadumesthrige, Kapila; Salley, Steven O.; Ng, K.Y. Simon [Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, MI 48202 (United States)

    2009-10-15

    The properties of biodiesel depend on the chemical structure of individual fatty acid methyl esters (FAME). In this work the chemical structure of fatty acid chains was modified by catalytic hydrogenation, epoxidation and hydroxylation under controlled conditions. Hydrolysis of ester functionality or oxidation of fatty acid chain was not observed during these reactions. The properties of hydrogenated FAME strongly depend on the hydrogenation time. The total saturated fatty acid (SFA) percentage increased from 29.3% to 76.2% after 2 h of hydrogenation. This hydrogenated FAME showed higher oxidation stability and higher cetane number but poor cold flow properties. Formation of trans FAME was observed during hydrogenation. Both hydroxylation and epoxidation resulted in a decrease of unsaturated fatty acid methyl ester (UFA) fraction. The percentages of total unsaturated FAME decreased 39% in the epoxidation reaction and 44% in the hydroxylation reaction. The addition of hydroxyl groups to the unsaturated regions of the fatty acid chain yields biodiesel with better cold flow properties, increased lubricity and slightly increased oxidative stability. However, epoxy FAME shows some interesting properties such as higher oxidation stability, higher cetane number and acceptable cold flow properties, which met the limits of ASTM D6751 biodiesel specifications. (author)

  5. Epoxidized Vegetable Oils Plasticized Poly(lactic acid Biocomposites: Mechanical, Thermal and Morphology Properties

    Directory of Open Access Journals (Sweden)

    Buong Woei Chieng

    2014-10-01

    Full Text Available Plasticized poly(lactic acid PLA with epoxidized vegetable oils (EVO were prepared using a melt blending method to improve the ductility of PLA. The plasticization of the PLA with EVO lowers the Tg as well as cold-crystallization temperature. The tensile properties demonstrated that the addition of EVO to PLA led to an increase of elongation at break, but a decrease of tensile modulus. Plasticized PLA showed improvement in the elongation at break by 2058% and 4060% with the addition of 5 wt % epoxidized palm oil (EPO and mixture of epoxidized palm oil and soybean oil (EPSO, respectively. An increase in the tensile strength was also observed in the plasticized PLA with 1 wt % EPO and EPSO. The use of EVO increases the mobility of the polymeric chains, thereby improving the flexibility and plastic deformation of PLA. The SEM micrograph of the plasticized PLA showed good compatible morphologies without voids resulting from good interfacial adhesion between PLA and EVO. Based on the results of this study, EVO may be used as an environmentally friendly plasticizer that can improve the overall properties of PLA.

  6. Lysophosphatidic acids are new substrates for the phosphatase domain of soluble epoxide hydrolase[S

    Science.gov (United States)

    Oguro, Ami; Imaoka, Susumu

    2012-01-01

    Soluble epoxide hydrolase (sEH) is a bifunctional enzyme that has a C-terminus epoxide hydrolase domain and an N-terminus phosphatase domain. The endogenous substrates of epoxide hydrolase are known to be epoxyeicosatrienoic acids, but the endogenous substrates of the phosphatase activity are not well understood. In this study, to explore the substrates of sEH, we investigated the inhibition of the phosphatase activity of sEH toward 4-methylumbelliferyl phosphate by using lecithin and its hydrolyzed products. Although lecithin itself did not inhibit the phosphatase activity, the hydrolyzed lecithin significantly inhibited it, suggesting that lysophospholipid or fatty acid can inhibit it. Next, we investigated the inhibition of phosphatase activity by lysophosphatidyl choline, palmitoyl lysophosphatidic acid, monopalmitoyl glycerol, and palmitic acid. Palmitoyl lysophosphatidic acid and fatty acid efficiently inhibited phosphatase activity, suggesting that lysophosphatidic acids (LPAs) are substrates for the phosphatase activity of sEH. As expected, palmitoyl, stearoyl, oleoyl, and arachidonoyl LPAs were efficiently dephosphorylated by sEH (Km, 3–7 μM; Vmax, 150–193 nmol/min/mg). These results suggest that LPAs are substrates of sEH, which may regulate physiological functions of cells via their metabolism. PMID:22217705

  7. Lysophosphatidic acids are new substrates for the phosphatase domain of soluble epoxide hydrolase.

    Science.gov (United States)

    Oguro, Ami; Imaoka, Susumu

    2012-03-01

    Soluble epoxide hydrolase (sEH) is a bifunctional enzyme that has a C-terminus epoxide hydrolase domain and an N-terminus phosphatase domain. The endogenous substrates of epoxide hydrolase are known to be epoxyeicosatrienoic acids, but the endogenous substrates of the phosphatase activity are not well understood. In this study, to explore the substrates of sEH, we investigated the inhibition of the phosphatase activity of sEH toward 4-methylumbelliferyl phosphate by using lecithin and its hydrolyzed products. Although lecithin itself did not inhibit the phosphatase activity, the hydrolyzed lecithin significantly inhibited it, suggesting that lysophospholipid or fatty acid can inhibit it. Next, we investigated the inhibition of phosphatase activity by lysophosphatidyl choline, palmitoyl lysophosphatidic acid, monopalmitoyl glycerol, and palmitic acid. Palmitoyl lysophosphatidic acid and fatty acid efficiently inhibited phosphatase activity, suggesting that lysophosphatidic acids (LPAs) are substrates for the phosphatase activity of sEH. As expected, palmitoyl, stearoyl, oleoyl, and arachidonoyl LPAs were efficiently dephosphorylated by sEH (Km, 3-7 μM; Vmax, 150-193 nmol/min/mg). These results suggest that LPAs are substrates of sEH, which may regulate physiological functions of cells via their metabolism.

  8. Properties of composite laminates based on basalt fibers with epoxidized vegetable oils

    International Nuclear Information System (INIS)

    Samper, M.D.; Petrucci, R.; Sanchez-Nacher, L.; Balart, R.; Kenny, J.M.

    2015-01-01

    Highlights: • New environmentally friendly composites from biobased epoxies and basalt fibers. • Improved performance with conventional silane treatment on basalt fabrics. • Composites with excellent appearance due to basalt shiny brown color. • Potential applications as substitute of glass fiber reinforced composites in engineering design. • Processing with conventional resin transfer molding (RTM) techniques. - Abstract: This paper deals with the development of polymeric materials derived from epoxidized vegetable oils which have been used in the manufacture of laminated composite materials with basalt fabrics. Epoxidized linseed oil (ELO) and epoxidized soybean oil (ESBO) were used as biobased matrices. The basalt fabrics were modified with amino-silane and glycidyl-silane to increase fiber–matrix interactions. The curing behavior of both resins was evaluated by differential scanning calorimetry (DSC) and oscillatory rheometry (OR). The evaluation of mechanical properties was made by tensile, flexural and Charpy tests. The extent of the fiber–matrix interactions among interface was evaluated by scanning electron microscopy (SEM). The obtained results revealed that surface modification of basalt fibers with glycidyl-silane clearly improves the mechanical properties of the composites. The use of the ELO resin as matrix for composite laminates improved substantially the mechanical performance compared to composites made with ESBO

  9. Comparative Study of Chemical, Mechanical, Thermal, and Barrier Properties of Poly(Lactic Acid Plasticized with Epoxidized Soybean Oil and Epoxidized Palm Oil

    Directory of Open Access Journals (Sweden)

    Yee Bond Tee

    2015-12-01

    Full Text Available To investigate epoxidized palm oil’s (EPO potential as plasticizer for poly(lactic acid (PLA, its plasticizing effect was compared with commercialized epoxidized soybean oil (ESO. The plasticizers were respectively melt-compounded into PLA at 3, 5, 10, and 15 wt.%. As it was aimed for the blends to be characterized towards packaging appropriate for food products, they were hot-pressed into ~0.3-mm sheets, which is the approximate thickness of clamshell packaging. Fourier transform infrared spectroscopy (FTIR confirmed the plasticizers’ compatibility with PLA. At similar loadings, EPO was superior in reinforcing elongation at break (EAB, thermal, and barrier properties of PLA. The ductility of PLA was notably improved to 50.0% with addition of 3 wt.% of EPO. From thermogravimetric analysis (TGA, PLA/EPO5 improved PLA’s thermal stability, while all PLA/ESO blends reported reduced thermal stability. From differential scanning calorimetry (DSC, the increase in crystallinity and the shifts in enthalpy of fusions in all plasticized blends denoted facilitation of PLA to form thermally stable α-form crystals. The addition of EPO enabled PLA to become highly impermeable to oxygen, which can extend its potential in packaging extensive range of oxygen sensitive food.

  10. Highly selective sulfur ylide mediated asymmetric epoxidations and aziridinations using an inexpensive chiral sulfide and applications to the synthesis of quinine and quinidine (abstract)

    International Nuclear Information System (INIS)

    Arshad, M.; Illa, O.; Mcgarrigle, E.M.

    2011-01-01

    Asymmetric sulfur ylide mediated epoxidation, which is considered a complimentary method to asymmetric epoxidation of alkene has been utilized as a key step in the asymmetric total synthesis of complex cinchona alkaloids quinine and quinidine. Isothiocineole 1, which was readily available in one step from very inexpensive starting materials, is employed as a chiral sulfide to prepare the desired sulfonium salt 2. The semi-stabilised ylide derived from this salt on epoxidation with meroquinene aldehyde 3, afforded the required epoxide 4 in 81% yield and 89:11 diastereoselectivity (trans/cis). The epoxide was converted to the target quinine 5 in 73% yield over four steps in one pot. Similarly, the opposite enantiomer of isothiocineole was used to synthesise the corresponding sulfonium salt, which on reaction with meroquinene aldehyde gave epoxide in 73% yield and 84:16 diastereoselectivity (trans/cis). This epoxide was transformed to the target quinidine in 78% yield over four steps in one pot. The epoxidation reactions proceeded under reagent control with high trans selectivity. The effect of sulfide and ylide substituents on the stereochemical outcome of the epoxidation reaction is also prescribed. (author)

  11. Benzo[a]pyrene treatment leads to changes in nuclear protein expression and alternative splicing

    Energy Technology Data Exchange (ETDEWEB)

    Yan Chunlan; Wu Wei [Department of Toxicology, Zhejiang University School of Public Health, 388 Yu-Hang-Tang Road, Hangzhou, Zhejiang 310058 (China); Li Haiyan [Department of Toxicology, Zhejiang University School of Public Health, 388 Yu-Hang-Tang Road, Hangzhou, Zhejiang 310058 (China); Huzhou Maternity and Child Care Hospital, Huzhou, Zhejiang 313000 (China); Zhang Guanglin [Department of Toxicology, Zhejiang University School of Public Health, 388 Yu-Hang-Tang Road, Hangzhou, Zhejiang 310058 (China); Duerksen-Hughes, Penelope J. [Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92354 (United States); Zhu Xinqiang, E-mail: zhuxq@zju.edu.cn [Department of Toxicology, Zhejiang University School of Public Health, 388 Yu-Hang-Tang Road, Hangzhou, Zhejiang 310058 (China); Yang Jun, E-mail: gastate@zju.edu.cn [Department of Toxicology, Zhejiang University School of Public Health, 388 Yu-Hang-Tang Road, Hangzhou, Zhejiang 310058 (China); Zhejiang-California International Nanosystems Institute, Hangzhou, Zhejiang 310029 (China)

    2010-04-01

    Benzo[a]pyrene (BaP) is a potent pro-carcinogen generated from the combustion of fossil fuel and cigarette smoke. Previously, using a proteomic approach, we have shown that BaP can induce changes in the expression of many cellular proteins, including transcription regulators. In the present study, using a similar approach, we examined the nuclear protein response to BaP in HeLa cells and found that BaP treatment caused expression changes in many nuclear proteins. Twenty-four of these proteins were successfully identified, several of which are involved in the alternative splicing of mRNA, DNA replication, recombination, and repair. The changed expression levels were further confirmed by immunoblot analysis using specific antibodies for two proteins, Lamin A and mitotic checkpoint protein Bub3. The nuclear localization of these two proteins was also confirmed by confocal microscopy. To determine whether alternative splicing was activated following BaP treatment, we examined Fas and CD44, two genes previously shown to be targets of alternative splicing in respond to DNA damage. While no significant activation of alternative splicing was observed for Fas, CD44 splicing variants were found after BaP treatment. Together, these data show that DNA damage induces dramatic changes in nuclear protein expression, and that alternative splicing might be involved in the cellular response to DNA damage.

  12. Chemical sensing of Benzo[a]pyrene using Corchorus depressus fluorescent flavonoids.

    Science.gov (United States)

    Ahmad, Wajiha; Rana, Nosheen Fatima; Riaz, Sundus; Ahmad, Nasir Mehmood; Hameed, Maryam; Naeem, Ayesha; Tahir, Rabbiya

    2018-04-01

    Plant phytochemicals, such as flavonoids are in use for the development of optical biosensor. Benzo[a]pyrene (B[a]P), is a pervasive environmental and dietary carcinogen. A fluorescent assay is developed using plant isolated flavonoid for the detection of B[a]P. High content saponins are excluded from the flavonoid-containing methanolic extract of Corchorus depressus by implying reduction of silver ions by saponins resulting in formation of silver nanoparticles. Isolated plant flavonoids are used to develop a spectrofluorometric assay for the detection of B[a]P. Decrease in the flavonoid fluorescence intensity by B[a]P is found to be based on both static and dynamic quenching. Specificity of the assay for B[a]P was tested for other carcinogens belonging to different classes of compounds. Flavonoids-mediated sensing can be implied for the development of new generation of nanoparticle-based biosensors that can be more sensitive and less susceptible to external factors, such as temperature and humidity.

  13. Benzo[a]pyrene and Benzo[k]fluoranthene in Some Processed Fish and Fish Products

    Directory of Open Access Journals (Sweden)

    Olatunde S. Olatunji

    2015-01-01

    Full Text Available In this study, the concentration levels of the probable carcinogenic PAH fractions, benzo[a]pyrene (BaP and benzo[k]fluoranthrene (BkF in fillets of some processed fish species were investigated. Fish species comprising Merluccius poli (hake, Tyrsites atun (snoek, Seriola lalandi (yellow-tail and Brama brama (angel fish were bought in fish shops at Gordon’s Bay, Western Cape, South Africa. The fish were gutted, filleted and prepared for edibility by frying, grilling and boiling. Polycyclic aromatic hydrocarbons were extracted from each homogenized fish sample, cleaned-up using solid phase extraction (SPE, and analysed for the PAH fractions, BaP and BkF using a Gas Chromatograph coupled with a Flame Ionization Detector (GC-FID. The sum of the two PAHs (∑2PAH i.e., BaP and BkF ranged between 0.56 and 1.46 µg/kg, in all boiled, grilled and fried fish species. The fried fish extracts showed significantly higher (p < 0.05 abundance of ∑2PAH, than grilled and boiled fish. Dietary safety and PAHs toxicity was also discussed.

  14. Fingerprinting of traditional Chinese medicines on the C18-Diol mixed-mode column in online or offline two-dimensional liquid chromatography on the single column modes.

    Science.gov (United States)

    Wang, Qing; Tong, Ling; Yao, Lin; Zhang, Peng; Xu, Li

    2016-06-05

    In the present study, a mixed-mode stationary phase, C18-Diol, was applied for fingerprint analysis of traditional Chinese medicines. Hydrophobic, hydrogen bonding and electrostatic interactions were demonstrated to contribute the retention separately or jointly, which endowed the C18-Diol stationary phase with distinct selectivity compared to the bare C18 one. The separation of total alkaloids extracted from Fritillaria hupehensis was compared on the C18-Diol and conventional C18 column with the greater resolving power and better symmetry responses on the former one. Besides, a novel two-dimensional liquid chromatography on the single column (2D-LC-1C) was realized on C18-Diol with the offline mode for the alcohol extract of Fritillaria hupehensis and online mode for Ligusticum chuanxiong Hort. The early co-eluted extracted components with great polarity on the first dimension were reinjected on the same column and well separated on the second dimension. The results exhibited that the two complementary RPLC and HILIC modes on C18-Diol stationary phase enhanced the separation capacity and revealed more abundant chemical information of the sample, which was a powerful tool in analyzing complex herbal medicines. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Iridium- and ruthenium-catalysed synthesis of 2,3-disubstituted indoles from anilines and vicinal diols

    DEFF Research Database (Denmark)

    Tursky, Matyas; Lorentz-Petersen, Linda Luise Reeh; Olsen, L. B.

    2010-01-01

    A straightforward and atom-economical method is described for the synthesis of 2,3-disubstituted indoles. Anilines and 1,2-diols are condensed under neat conditions with catalytic amounts of either [Cp*IrCl2](2)/MsOH or RuCl3 center dot xH(2)O/phosphine (phosphine = PPh3 or xantphos). The reactio...... the alpha-hydroxyimine which rearranges to the corresponding alpha-aminoketone. Acid-or metal-catalysed electrophilic ring-closure with the release of water then furnishes the indole product....

  16. In-Situ Generated Graphene as the Catalytic Site for Visible-Light Mediated Ethylene Epoxidation on AG Nanocatalysts

    Science.gov (United States)

    Zhang, Xueqiang Alex; Jain, Prashant

    2017-06-01

    Despite the harsh conditions for chemical conversion, ethylene oxide produced from ethylene epoxidation on Ag-based heterogeneous catalyst constitutes one of the largest volume chemicals in chemical industry. Recently, photocatalytic epoxidation of ethylene over plasmonic Ag nanoparticles enables the chemical conversion under significantly decreased temperature and ambient pressure conditions. Yet a detailed understanding of the photocatalytic process at the reactant/catalyst interface is under debate. Surface enhanced Raman spectroscopy (SERS) is a powerful vibrational spectroscopy technique that enables the localized detection of rare and/or transient chemical species with high sensitivity under in situ and ambient conditions. Using SERS, we are able to monitor at individual sites of an Ag nanocatalyst the visible-light-mediated adsorption and epoxidation of ethylene. From detected intermediates, we find that the primary step in the photoepoxidation is the transient formation of graphene catalyzed by the Ag surface. Density functional theory (DFT) simulations that model the observed SERS spectra suggest that the defective edge sites of the graphene formed on Ag constitute the active site for C2H4 adsorption and epoxidation. Further studies with pre-formed graphene/Ag catalyst composites confirm the indispensable role of graphene in visible-light-mediated ethylene epoxidation. Carbon is often thought to be either an innocent support or a poison for metallic catalysts; however our studies reveal a surprising role for crystalline carbon layers as potential co-catalysts.

  17. Influence of oil composition on the formation of fatty acid esters of 2-chloropropane-1,3-diol (2-MCPD) and 3-chloropropane-1,2-diol (3-MCPD) under conditions simulating oil refining.

    Science.gov (United States)

    Ermacora, Alessia; Hrncirik, Karel

    2014-10-15

    The toxicological relevance and widespread occurrence of fatty acid esters of 2-chloropropane-1,3-diol (2-MCPD) and 3-chloropropane-1,2-diol (3-MCPD) in refined oils and fats have recently triggered an interest in the mechanism of formation and decomposition of these contaminants during oil processing. In this work, the effect of the main precursors, namely acylglycerols and chlorinated compounds, on the formation yield of MCPD esters was investigated in model systems simulating oil deodorization. The composition of the oils was modified by enzymatic hydrolysis, silica gel purification and application of various refining steps prior to deodorization (namely degumming, neutralization, bleaching). Partial acylglycerols showed greater ability, than did triacylglycerols, to form MCPD esters. However, no direct correlation was found between these two parameters, since the availability of chloride ions was the main limiting factor in the formation reaction. Polar chlorinated compounds were found to be the main chloride donors, although the presence of reactive non-polar chloride-donating species was also observed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Asymmetric aminolytic kinetic resolution of racemic epoxides using recyclable chiral polymeric Co(III)-salen complexes: a protocol for total utilization of racemic epoxide in the synthesis of (R)-Naftopidil and (S)-Propranolol.

    Science.gov (United States)

    Kumar, Manish; Kureshy, Rukhsana I; Shah, Arpan K; Das, Anjan; Khan, Noor-ul H; Abdi, Sayed H R; Bajaj, Hari C

    2013-09-20

    Chiral polymeric Co(III) salen complexes with chiral ((R)/(S)-BINOL, diethyl tartrate) and achiral (piperazine and trigol) linkers with varying stereogenic centers were synthesized for the first time and used as catalysts for aminolytic kinetic resolution (AKR) of a variety of terminal epoxides and glycidyl ethers to get enantio-pure epoxides (ee, 99%) and N-protected β-amino alcohols (ee, 99%) with quantitative yield in 16 h at RT under optimized reaction conditions. This protocol was also used for the synthesis of two enantiomerically pure drug molecules (R)-Naftopidil (α1-blocker) and (S)-Propranolol (β-blocker) as a key step via AKR of single racemic naphthylglycidyl ether with Boc-protected isoproylamine with 100% epoxide utilization at 1 g level. The catalyst 1 was successfully recycled for a number of times.

  19. Effect of ageing on benzo[a]pyrene extractability in contrasting soils

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Luchun [CERAR-Centre for Environmental Risk Assessment and Remediation and Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Naidu, Ravi, E-mail: Ravi.Naidu@newcastle.edu.au [CERAR-Centre for Environmental Risk Assessment and Remediation and Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Liu, Yanju; Palanisami, Thavamani; Dong, Zhaomin; Mallavarapu, Megharaj [CERAR-Centre for Environmental Risk Assessment and Remediation and Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Semple, Kirk T. [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

    2015-10-15

    Highlights: • In vitro assessment of B[a]P in contaminated soils using 4 different methods. • An exponential kinetic model fits well with the extractability data. • Fitting parameter and {sup 14}C residue correlates with key soil properties. • Fractionation of B[a]P was obtained based on extractability by extractants. - Abstract: Changes in benzo[a]pyrene (B[a]P) extractability over 160 days ageing in four contrasting soils varying in organic matter content and clay mineralogy were investigated using dichloromethane: acetone 1:1 (DCM/Ace), 60 mM hydroxypropyl-β-cyclodextrin (HPCD) solution, 1-butanol (BuOH) and Milli-Q water. The B[a]P extractability by the four methods decreased with ageing and a first-order exponential model could be used to describe the kinetics of release. Correlation of the kinetic rate constant with major soil properties showed a significant effect of clay and sand contents and pore volume fraction (<6 nm) on sequestration of the desorbable fraction (by HPCD) and the water-extractable fraction. Analysis of {sup 14}C-B[a]P in soils after ageing showed a limited loss of B[a]P via degradation. Fractionation of B[a]P pools associated with the soil matrix was analysed according to extractability of B[a]P by the different extraction methods. A summary of the different fractions is proposed for the illustration of the effect of ageing on different B[a]P-bound fractions in soils. This study provides a better understanding of the B[a]P ageing process associated with different fractions and also emphasises the extraction capacity of the different methods employed.

  20. Effect of ageing on benzo[a]pyrene extractability in contrasting soils

    International Nuclear Information System (INIS)

    Duan, Luchun; Naidu, Ravi; Liu, Yanju; Palanisami, Thavamani; Dong, Zhaomin; Mallavarapu, Megharaj; Semple, Kirk T.

    2015-01-01

    Highlights: • In vitro assessment of B[a]P in contaminated soils using 4 different methods. • An exponential kinetic model fits well with the extractability data. • Fitting parameter and 14 C residue correlates with key soil properties. • Fractionation of B[a]P was obtained based on extractability by extractants. - Abstract: Changes in benzo[a]pyrene (B[a]P) extractability over 160 days ageing in four contrasting soils varying in organic matter content and clay mineralogy were investigated using dichloromethane: acetone 1:1 (DCM/Ace), 60 mM hydroxypropyl-β-cyclodextrin (HPCD) solution, 1-butanol (BuOH) and Milli-Q water. The B[a]P extractability by the four methods decreased with ageing and a first-order exponential model could be used to describe the kinetics of release. Correlation of the kinetic rate constant with major soil properties showed a significant effect of clay and sand contents and pore volume fraction (<6 nm) on sequestration of the desorbable fraction (by HPCD) and the water-extractable fraction. Analysis of 14 C-B[a]P in soils after ageing showed a limited loss of B[a]P via degradation. Fractionation of B[a]P pools associated with the soil matrix was analysed according to extractability of B[a]P by the different extraction methods. A summary of the different fractions is proposed for the illustration of the effect of ageing on different B[a]P-bound fractions in soils. This study provides a better understanding of the B[a]P ageing process associated with different fractions and also emphasises the extraction capacity of the different methods employed

  1. Dermal bioavailability of benzo[a]pyrene on lampblack: implications for risk assessment.

    Science.gov (United States)

    Stroo, Hans F; Roy, Timothy A; Liban, Cris B; Kreitinger, Joseph P

    2005-06-01

    Lampblack is the principal source of contamination in soils at manufactured gas plant (MGP) sites where oil was used as the feedstock. Risks and cleanup criteria at these sites are determined primarily by the total carcinogenic polynuclear aromatic hydrocarbon (PAH) content, particularly the concentration of benzo[a]pyrene (BaP). Dermal contact with soils at oil-gas MGP sites is a significant component of the overall risks. Seven samples were collected from oil-gas MGP sites and the steady-state dermal fluxes were measured over 96 h in vitro. The standard dermal bioassay technique (in which 3H-BaP is added to the soil matrix) was modified to allow direct measurement of the dermal absorption of the native BaP in the samples. The experimentally derived dermal absorption factors for BaP were 14 to 107 times lower than the default assumption of 15% over 24 h (55-fold lower on average). The dermal fluxes were correlated positively to the total BaP and total carbon concentrations. The measured dermal absorption factors were compared to the default risk-assessment calculations for all seven samples. The calculated excess cancer risk was reduced as a result of using the measured absorption factors by 97% on average (with reductions ranging from 93 to 99%). This work indicates the risks at oil-gas MGP sites currently are overestimated by one to two orders of magnitude, and provides a protocol for the testing and data analysis needed to generate site-specific cleanup levels.

  2. Effect of the Apulia air quality plan on PM10 and benzo(apyrene exceedances

    Directory of Open Access Journals (Sweden)

    L. Trizio

    2016-03-01

    Full Text Available During the last years, several exceedances of PM10 and benzo(apyrene limit values exceedances were recorded in Taranto, a city in southern Italy included in so-called areas at high risk of environmental crisis because of the presence of a heavy industrial district including the largest steel factory in Europe. A study of these critical pollution events showed a close correlation with the wind coming from the industrial site to the adjacent urban area. During 2011, at monitoring sites closes to the industrial area, at least the 65% of PM10 exceedances were related to wind day conditions (characterized by at least 3 consecutive hours of wind coming from 270-360±2deg with an associated speed higher than 7 m/s. For this reason, in 2012 an integrated environmental permit and a regional air quality plan were enacted to reduce pollutant emissions from industrial plants. A study of PM10 levels registered during windy days was performed during critical episodes of pollution highlighting that the difference between windy days and no windy days’ concentrations reduces from 2012 to 2014 in industrial site. False negative events (verified ex-post by observed meteorological data not identified by the forecast model - did not show a significant influence on PM concentration: PM10 values were comparable and sometimes lower than windy days levels. It is reasonable that the new scenario with a relevant reduction emissions form Ilva plant reduced the pollutants contribution from industrial area, contributing to PM10 levels decrease, also in false negative events.

  3. Transcriptional responses of Acropora hyacinthus embryo under the benzo(a)pyrene stress by deep sequencing.

    Science.gov (United States)

    Xiao, Rong; Zhou, Hailong; Chen, Chien-Min; Cheng, Huamin; Li, Hongwu; Xie, Jia; Zhao, Hongwei; Han, Qian; Diao, Xiaoping

    2018-04-24

    Coral embryos are a critical and sensitive period for the early growth and development of coral. Benzo(a)pyrene (BaP) is widely distributed in the ocean and has strong toxicity, but there is little information on the toxic effects to coral embryos exposed to this widespread environmental contaminant. Thus, in this study, we utilized the Illumina Hiseq™ 4000 platform to explore the gene response of Acropora hyacinthus embryos under the BaP stress. A total of 130,042 Unigenes were obtained and analyzed, and approximately 37.67% of those matched with sequences from four different species. In total, 2606 Unigenes were up-regulated, and 3872 Unigenes were down-regulated. After Gene Ontology (GO) annotation, the results show that the "cellular process" and "metabolic process" were leading in the category of biological processes, which the "binding" and "catalytic activity" were the most abundant subcategories in molecular function. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the most differentially expressed genes (DEGs) were enriched, as well as down-regulated in the pathways of oxidative phosphorylation, metabolism of xenobiotics, immune-related genes, apoptosis and human disease genes. At the same time, 388,197 of Single-nucleotide Polymorphisms (SNPs) and 6164 of Simple Sequence Repeats (SSRs) were obtained, which can be served as the richer and more valuable SSRs molecular markers in the future. The results of this study can help to better understand the toxicological mechanism of coral embryo exposed to BaP, and it is also essential for the protection and restoration of coral reef ecosystem in the future. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Assessment of sediment quality based on toxic equivalent benzo[a]Pyrene concentration

    International Nuclear Information System (INIS)

    King, T.L.; Lee, K.

    2004-01-01

    This study examined benzo[a]pyrene (B[a]P) as an indicator and its thresholds for polycyclic aromatic hydrocarbons (PAH) in sediments. The indicator, based on toxicity and carcinogenic effects, was selected to assess the marine environment and changes in marine environmental quality (MEQ) in Sydney Harbour, Nova Scotia. It was shown that the bioavailability of B[a]P and other PAHs is greatly affected by the quality and quantity of dissolved organic matter and organic carbon content. Two coal coke facilities were constructed on the shore of Sydney Harbour in the 19th century. For many years, the coke-ovens discharged toxic liquid effluent through the Tar Ponds into the harbour, contaminating the ground and surface water with arsenic, lead and other toxins. It also led to the accumulation of PAHs and polychlorinated biphenyls. A recent assessment of PAH contamination of Sydney Harbour has focused on the exposure of organisms to contaminants as well as the biological effects on the organisms. All samples collected from the South Arm of Sydney Harbour exceeded the upper threshold of established regulatory guidelines. Samples from the Northwest Arm were within regulatory limits, suggesting that industrial and municipal sources were the primary sources of pollution. PAH concentrations were used to identify sediments that exceed effects thresholds based on MEQ guidelines. The results were compared to actual observations of biological effects. Toxic equivalency factors were established for B[a]P and other PAHs in order to estimate cumulative exposure levels. The concentrations can be compared to regulatory sediment quality guidelines established in Canada and the United States for the protection of marine life. 34 refs., 6 tabs., 2 figs

  5. Selective Propene Epoxidation on Immobilized Au6-10 Clusters: The Effect of Hydrogen and Water on Activity and Selectivity

    DEFF Research Database (Denmark)

    Lee, Sungsik; Molina, Luis M.; López, María J.

    2009-01-01

    Epoxidation made easy: Subnanometer gold clusters immobilized on amorphous alumina result in a highly active and selective catalyst for propene epoxidation. The highest selectivity is found for gas mixtures involving oxygen and water, thus avoiding the use of hydrogen. Ab initio DFT calculations ...

  6. Synthesis and characterization of biodegradable poly (ethylene glycol) and poly (caprolactone diol) end capped poly (propylene fumarate) cross linked amphiphilic hydrogel as tissue engineering scaffold material.

    Science.gov (United States)

    Krishna, Lekshmi; Jayabalan, Muthu

    2009-12-01

    Biodegradable poly (caprolactone diol-co-propylene fumarate-co-ethylene glycol) amphiphilic polymer with poly (ethylene glycol) and poly (caprolactone diol) chain ends (PCL-PPF-PEG) was prepared. PCL-PPF-PEG undergoes fast setting with acrylamide (aqueous solution) by free radical polymerization and produces a crosslinked hydrogel. The cross linked and freeze-dried amphiphilic material has porous and interconnected network. It undergoes higher degree of swelling and water absorption to form hydrogel with hydrophilic and hydrophobic domains at the surface and appreciable tensile strength. The present hydrogel is compatible with L929 fibroblast cells. PCL-PPF-PEG/acrylamide hydrogel is a candidate scaffold material for tissue engineering applications.

  7. Potassium cyanate-induced modification of toxic and mutagenic effects of gamma-radiation and benzo(A)-pyrene

    International Nuclear Information System (INIS)

    Serebryanyj, A.M.; Sal'nikova, L.E.; Bakhitova, L.M.; Pashin, Yu.V.; AN SSSR, Moscow

    1989-01-01

    In experiments with CHO-AT3-2 cell culture, a study was made of the effect of potassium cyanate (KNCO) on the effect of gamma-radiation and benzo(a)pyrene (BP) by the following tests: cell viability, induction of cells with micronuclei and fragmentated nuclei and mutations by thymidinekinase (TK) and Na + /K + -ATPase loci. Some tests have revealed the increase in the effect of gamma-radiation and BP produced by potassium cyanate. It is suggested that sensitizing effects are related to repair system inhibition and/or changes in the cell chromatin structure produced by KNCO

  8. Monitoring of radiolytic degradation of benzo(a)pyrene using γ-rays in aqueous media by HPLC

    International Nuclear Information System (INIS)

    Butt, S. Bilal; Qureshi, Rashid N.; Ahmed, Shafaat

    2005-01-01

    Poly nuclear aromatic hydrocarbons (PAHs) are generated in the environment by various industrial processes and anthropogenic activities. These compounds are quite stable and persist in the environment due to the aromatic bonding within the rings. Benzo(a)pyrene (B(a)P) is a potential carcinogenic and conditions for its degradation have been optimized by investigating γ-ray dose intensity, its concentration effect and the influence of surfactant presence. HPLC has been used to monitor the degree of degradation of B(a)P under the optimum conditions

  9. A Bimetallic Aluminium(Salphen) Complex for the Synthesis of Cyclic Carbonates from Epoxides and Carbon Dioxide.

    Science.gov (United States)

    Wu, Xiao; North, Michael

    2017-01-10

    A bimetallic aluminium(salphen) complex is reported as a sustainable, efficient and inexpensive catalyst for the synthesis of cyclic carbonates from epoxides and carbon dioxide. In the presence of this complex and tetrabutylammonium bromide, terminal and internal epoxides reacted at 50 °C and 10 bar carbon dioxide pressure to afford their corresponding cyclic carbonates in yields of 50-94 % and 30-71 % for terminal and internal cyclic carbonates, respectively. Mechanistic studies using deuterated epoxides and an analogous monometallic aluminium(salphen) chloride complex support a mechanism for catalysis by the bimetallic complex, which involves intramolecular cooperative catalysis between the two aluminium centres. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Photochemical epoxidation of olefins by visible light in a redox system involving Sb(V) tetraphenylporphyrin and water

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Haruo; Hida, Mitsuhiko (Tokyo Metropolitan Univ. (Japan))

    1989-03-25

    The authors explore electron donors from the viewpoint of solar energy storage. Much attention has been focused on how a water molecule can be incorporated into electron donor system. In this paper, the authors describe a photochemical epoxidation of alkene sensitized by Sb(V)-, P(V)-, Sn(IV)-, Ge(IV)- tetraphenylporphyrin (TPP) with higher oxidation potential than 1.0 Volts vs. NHE in redox systems with a water molecule as an electron donor. The water molecule acts as an electron donor, and alkene acts as an oxygen atom acceptor in this photoredox system. Epoxidation of alkenes usually requires strong oxidizing agents either by the thermal or photochemical method. This is the first example of the photochemical epoxide formation from alkene and water without any strong oxidizing agent. 1 fig.

  11. Metabolism of isoeugenol via isoeugenol-diol by a newly isolated strain of Bacillus subtilis HS8.

    Science.gov (United States)

    Zhang, Yongmei; Xu, Ping; Han, Shuai; Yan, Haiqin; Ma, Cuiqing

    2006-12-01

    A bacterium designated as HS8 was newly isolated from soil based on its ability to degrade isoeugenol. The strain was identified as Bacillus subtilis according to its 16S rDNA sequence analysis and biochemical characteristics. The metabolic pathway for the degradation of isoeugenol was examined. Isoeugenol-diol, for the first time, was detected as an intermediate from isoeugenol to vanillin by a bacterial strain. Isoeugenol was converted to vanillin via isoeugenol-diol, and vanillin was then metabolized via vanillic acid to guaiacol by strain HS8. These metabolites, vanillin, vanillic acid, and guaiacol, are all valuable aromatic compounds in flavor production. At the same time, the bipolymerization of isoeugenol was observed, which produced dehydrodiisoeugenol and decreased the vanillin yield. High level of vanillic acid decarboxylase activity was detected in cell-free extract. These findings provided a detailed profile of isoeugenol metabolism by a B. subtilis strain for the first time, which would improve the production of valuable aromatic compounds by biotechnology.

  12. Cross-Linked Dependency of Boronic Acid-Conjugated Chitosan Nanoparticles by Diols for Sustained Insulin Release

    Directory of Open Access Journals (Sweden)

    Nabil A. Siddiqui

    2016-10-01

    Full Text Available Boronic acids have been widely investigated for their potential use as glucose sensors in glucose responsive polymeric insulin delivery systems. Interactions between cyclic diols and boronic acids, anchored to polymeric delivery systems, may result in swelling of the delivery system, releasing the drug. In this study, 4-formylphenylboronic acid conjugated chitosan was formulated into insulin containing nanoparticles via polyelectrolyte complexation. The nanoparticles had an average diameter of 140 ± 12.8 nm, polydispersity index of 0.17 ± 0.1, zeta potential of +19.1 ± 0.69 mV, encapsulation efficiency of 81% ± 1.2%, and an insulin loading capacity of 46% ± 1.8% w/w. Changes in size of the nanoparticles and release of insulin were type of sugar- and concentration-dependent. High concentration of diols resulted in a sustained release of insulin due to crosslink formation with boronic acid moieties within the nanoparticles. The formulation has potential to be developed into a self-regulated insulin delivery system for the treatment of diabetes.

  13. Preparation and surface active properties of oxypropylated diol monoesters of fatty acids with an amide oxime terminal group

    Directory of Open Access Journals (Sweden)

    Eissa, A. M.F.

    1994-10-01

    Full Text Available Locally produced non-edible oil, namely, rice bran oil (R.B.O. was utilized as starting materials for preparing new nonionic surfactant. Oxypropylated diol monoesters of linoleic and rice bran oil fatty acids were prepared. Also amide oxime derivatives were obtained. Surface active properties of these compounds were measured. Under neutral condition amide eximes served as nonionic surfactants and their properties were similar to other oxypropylated monoesters.

    Se ha utilizado un aceite no comestible de producción local, denominado, aceite de salvado de arroz (R.B.O. como materia prima para la preparación de nuevos tensioactivos no iónicos. Se prepararon diol monoésteres oxipropilados de ácido linoleico y ácidos grasos de aceite de salvado de arroz. También se obtuvieron los derivados de amido oxima. Se midieron las propiedades de tensión superficial de estos compuestos. Bajo condiciones neutras las amido eximas sirvieron como tensioactivos no iónicos y sus propiedades fueron similares a los de otros monoésteres oxipropilados.

  14. Studies on Poly(propylene fumarate-co-caprolactone diol Thermoset Composites towards the Development of Biodegradable Bone Fixation Devices

    Directory of Open Access Journals (Sweden)

    M. Jayabalan

    2009-01-01

    Full Text Available The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene fumarate-co-caprolactone diol was also studied without any reinforcement for comparison. The reinforcing fibre acts as a barrier for the curing reaction leading to longer setting time and lesser cross-link density. The fibre and HA reinforced composites have almost the same compressive strength. Nonreinforced material undergoes greater degree of swelling. Among the reinforced materials, the hydroxyapatite reinforced composite has a much higher swelling percentage than the fibre reinforced one. The studies on in vitro degradation of the cured materials reveal hydrolytic degradation in Ringer's solution and PBS medium during aging. All the three materials are found to swell initially in Ringer's solution and PBS medium during aging and then undergo gradual degradation. Compression properties of these cross-linked composites increase with aging; HA reinforced composite has the highest compressive strength and compressive modulus, whereas the aged fibre-reinforced composite has the least compressive strength and modulus.

  15. Studies on Poly(propylene fumarate-co-caprolactone diol) Thermoset Composites towards the Development of Biodegradable Bone Fixation Devices.

    Science.gov (United States)

    Jayabalan, M

    2009-01-01

    The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol) thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene fumarate-co-caprolactone diol) was also studied without any reinforcement for comparison. The reinforcing fibre acts as a barrier for the curing reaction leading to longer setting time and lesser cross-link density. The fibre and HA reinforced composites have almost the same compressive strength. Nonreinforced material undergoes greater degree of swelling. Among the reinforced materials, the hydroxyapatite reinforced composite has a much higher swelling percentage than the fibre reinforced one. The studies on in vitro degradation of the cured materials reveal hydrolytic degradation in Ringer's solution and PBS medium during aging. All the three materials are found to swell initially in Ringer's solution and PBS medium during aging and then undergo gradual degradation. Compression properties of these cross-linked composites increase with aging; HA reinforced composite has the highest compressive strength and compressive modulus, whereas the aged fibre-reinforced composite has the least compressive strength and modulus.

  16. Regioselective Nucleophilic Ring Opening of Epoxides and Aziridines derived from Homoallylic Alcohols

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Groth, Thomas

    1997-01-01

    The regioselectivity of nucleophilic ring opening of some 3,4-epoxy and 3,4-aziridino alcohols has been studied. The nucleophiles chosen were complex hydrides (LiAlH4, Red-Al and DIBAL) and Lipshutz- or Gilman-type organocuprate reagents. The C-4 substituent in the substrates was varied in order...... to study steric and electronic effects on the ring opening reactions. For alkyl substituents at C-4, most of the results can be explained on the basis of intramolecular delivery of the nucleophile to C-3 via a six-membered transition state, leading to 1,4-diols or 1,4-amino alcohol derivatives. In general......, the epoxy alcohols gave poorer regioselectivity than the N-tosyl aziridino alcohols, for which selectivities of >95:5 were routinely obtained. The activating effect of a phenyl group at C-4 led to a switch in regiochemistry, with the 1,3-diol or 1,3-amino alcohol derivative as the major product. (C) 1997...

  17. Efficient Cycloaddition Reaction of Carbon Dioxide with Epoxide by Rhodamine Based Catalyst Under 1 atm Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Qing; Luo, Huadong; Cao, Di; Zhang, Haibo; Wang, Wenjing; Zhou, Xiaohai [Wuhan University, Wuhan (China)

    2012-06-15

    Rhodamine B (RhB) and rhodamine 6G (Rh6G) were employed as catalysts for the synthesis of cyclic carbonate from carbon dioxide and epoxide. It turned out that the catalytic activity of Rh6G was nearly 29 times higher than that of RhB at 1 atm pressure, 90 .deg. C. Furthermore, the catalytic efficiency of RhB and Rh6G was greatly enhanced with triethylamine as co-catalyst. Under the optimized conditions, the best isolated yield (93%) of cyclic carbonate was achieved without organic solvent and metal component

  18. Studies on whole cell fluorescence-based screening for epoxide hydrolases and Baeyer-Villiger monooxygenases

    International Nuclear Information System (INIS)

    Bicalho, Beatriz; Chen, Lu S.; Marsaioli, Anita J.; Grognux, Johann; Reymond, Jean-Louis

    2004-01-01

    Biocatalysis reactions were performed on microtiter plates (200 μL) aiming at the utilization of fluorogenic substrates (100 μmol L -1 ) for rapid whole cell screening for epoxide hydrolases (EHs) and Baeyer-Villiger monooxygenases (BVMOs). A final protocol was achieved for EHs, with 3 new enzymatic sources being detected (Agrobacterium tumefaciens, Pichia stipitis, Trichosporom cutaneum). The fluorogenic assay for BVMO did not work as expected. However, an approach to possible variables involved (aeration; pH) provided the first detection of a BVMO activity in T. cutaneum. (author)

  19. Direct gas-phase epoxidation of propylene to propylene oxide through radical reactions: A theoretical study

    Science.gov (United States)

    Kizilkaya, Ali Can; Fellah, Mehmet Ferdi; Onal, Isik

    2010-03-01

    The gas-phase radical chain reactions which utilize O 2 as the oxidant to produce propylene oxide (PO) are investigated through theoretical calculations. The transition states and energy profiles were obtained for each path. The rate constants were also calculated. The energetics for the competing pathways indicate that PO can be formed selectively due to its relatively low activation barrier (9.3 kcal/mol) which is in a good agreement with the experimental value (11 kcal/mol) of gas-phase propylene epoxidation. The formation of the acrolein and combustion products have relatively high activation barriers and are not favored. These results also support the recent experimental findings.

  20. Catalytic applications of immobilized ionic liquids for synthesis of cyclic carbonates from carbon dioxide and epoxides

    International Nuclear Information System (INIS)

    Kim, Dong-Woo; Roshan, Roshith; Tharun, Jose; Cherian, Amal; Park, Dae-Won

    2013-01-01

    The catalytic applicability of ionic liquids immobilized on various support materials such as silica, polystyrene and biopolymers in the cycloaddition of carbon dioxide with epoxides is reviewed in this work. Comparisons of the catalytic efficiency of these various catalysts have been done from the aspect of turnover number and reusability. The studies revealed that ionic liquids or support materials possessing hydrogen bonding capable groups exhibited enhanced catalytic activity towards cyclic carbonate synthesis. Moreover, the increased quest towards environmentally benign materials has renewed the search for biocompatible materials as support for ionic liquids

  1. Synthesis of Carbasugars from Aldonolactones: Ritter-Type Epoxide Opening of Polyhydroxylated Aminocyclopentanes

    DEFF Research Database (Denmark)

    Lundt, Inge; Johansen, Steen Karsk; Kornø, Hanne Tøfting

    1999-01-01

    Using the cis-fused cyclopentane-1,4-lactone, 1(R),5(S)-7(R),8(R)-dihydroxy-2-oxabicyclo[3.3.0]oct-3-one (1), as starting material, 5-deoxycarba-*-L-xylo-hexofuranose (6) together with ?- (12) and ?-1-amino-1,5-dideoxycarba-L-xylo-hexofuranose (16) have been prepared using a number...... of stereoselective transformations. The key step was the regioselective opening of the epoxide 1(R),5(S)-7(R),8(R)-epoxy-2-oxabicyclo[3.3.0]oct-3-one (4) with different nucleophiles....

  2. Studying the iodine leaching from the compositions based on epoxide resin and lead iodide

    International Nuclear Information System (INIS)

    Kalinin, N.N.; Elizarova, A.N.

    1988-01-01

    When studying iodine leaching, the possibility to use solid compositions, produced by incorporation of dry powdered lead iodide and its aqueous suspension into epoxide resin for long-term immobilization of iodine-129 under conditions of monitored storage, is evaluated. Analysis of the results obtained has shown that leaching rate in the first 4 days has the maximum value and constitutes (4.2 - 2700.0) x 10 -6 cm/day. Then the process of leaching is determined by diffusion mechanism. For samples, prepared by wet lead iodide incorporation the rate of leaching is higher than that of the corresponding samples prepared by dry compound incorporation

  3. Quantum chemical study of the mechanism of action of vitamin K epoxide reductase (VKOR)

    Science.gov (United States)

    Deerfield, David, II; Davis, Charles H.; Wymore, Troy; Stafford, Darrel W.; Pedersen, Lee G.

    Possible model, but simplistic, mechanisms for the action of vitamin K epoxide reductase (VKOR) are investigated with quantum mechanical methods (B3LYP/6-311G**). The geometries of proposed model intermediates in the mechanisms are energy optimized. Finally, the energetics of the proposed (pseudo-enzymatic) pathways are compared. We find that the several pathways are all energetically feasible. These results will be useful for designing quantum mechanical/molecular mechanical method (QM/MM) studies of the enzymatic pathway once three-dimensional structural data are determined and available for VKOR.

  4. Rapid epoxidation of palm acid oil with lipase action under microwave irradiation

    International Nuclear Information System (INIS)

    Saifuddin, N.; Wei Zhan Lee; Koh, X.N.; Ramesh, S.; Abdullah, S.F.

    2010-01-01

    In view of growing environmental concerns and tightened regulations over contaminants and pollution in the environment in recent years, calls for biodegradable and nontoxic vegetable oil-based lubricants are abound. They have very low volatility due to the higher molecular weight of the triacylglycerol molecule and a narrow range of viscosity changes with temperature. Polar ester groups in the molecule are able to adhere to metal surfaces, and therefore, possess good boundary lubrication properties. In addition, vegetable oils have high solubilising power for polar contaminants and additive molecules. However, vegetable oils show poor oxidative and thermal stability primarily due to the presence of unsaturation. The presence of ester functionality also renders these oils susceptible to hydrolytic breakdown. The proposed modification of the vegetable oils is an important manner to obtain potentially useful products using a renewable feedstock. In designing a green process to effectively carry out the epoxidation reaction, we report herein, an inexpensive, practical, safe and environmentally friendly method to epoxidize palm acid oil under extremely mild conditions. This work highlights the increased reaction rate of the epoxidation process when microwave irradiation is introduced. The starting material used is Palm Acid Oil, a by-product of the alkali refining process of palm oil. Acid oil can serve as an inexpensive raw materials and are very good substitute for neat vegetable oil such as palm oil for the production of bio lubricant. It is high in Free Fatty Acids (FFA) and is the ideal material for the epoxidation process due to the importance of FFAs in producing peroxy-acids as an oxygen carrier. The double bonds the triglycerides are reacted with a per acid, generated for safety reasons in situ using hydrogen peroxide. Novozym 435 acts as the catalyst in the process and with its good selectivity, the occurrence of by-products is controlled. The method and

  5. Epoxide resin coatings of cans - substance transfer to oil-containing foods possible

    OpenAIRE

    German Federal Institute for Risk Assessment

    2016-01-01

    Oily foods in cans can contain levels of Cyclo-di-BADGE (CdB) that present a health risk for high consumers. This is the result of a health risk assessment of the Federal Institute for Risk Assessment (BfR) in which the institute analysed data on the CdB content of canned fish preserved in oil. CdB is a molecule consisting of Bisphenol A (BPA) and Bisphenol A diglycidyl ether (BADGE). It is formed as a by-product during the production of epoxide resins which are, for example, used for the int...

  6. Exploration of Cocatalyst Effects on a Bimetallic Cobalt Catalyst System: Enhanced Activity and Enantioselectivity in Epoxide Polymerization

    KAUST Repository

    Widger, Peter C. B.; Ahmed, Syud M.; Coates, Geoffrey W.

    2011-01-01

    Organic ionic compounds were synthesized and investigated as cocatalysts with a bimetallic cobalt complex for enantioselective epoxide polymerization. The identities of both the cation and the anion were systematically varied, and the subsequent reactivity was studied. The nature of the ionic cocatalyst dramatically impacted the rate and enantioselectivity of the catalyst system. The ionic cocatalyst [P(N=P(N(CH2)4)3) 4 +][tBuCO2 -] in combination with a bimetallic cobalt complex produced a catalyst system that exhibited the greatest activity and selectivity for a variety of monosubstituted epoxides. © 2011 American Chemical Society.

  7. Exploration of Cocatalyst Effects on a Bimetallic Cobalt Catalyst System: Enhanced Activity and Enantioselectivity in Epoxide Polymerization

    KAUST Repository

    Widger, Peter C. B.

    2011-07-26

    Organic ionic compounds were synthesized and investigated as cocatalysts with a bimetallic cobalt complex for enantioselective epoxide polymerization. The identities of both the cation and the anion were systematically varied, and the subsequent reactivity was studied. The nature of the ionic cocatalyst dramatically impacted the rate and enantioselectivity of the catalyst system. The ionic cocatalyst [P(N=P(N(CH2)4)3) 4 +][tBuCO2 -] in combination with a bimetallic cobalt complex produced a catalyst system that exhibited the greatest activity and selectivity for a variety of monosubstituted epoxides. © 2011 American Chemical Society.

  8. Determination of Benzo(a)pyrene in Malaysian commercialized coffee powder using solid phase extraction and gas chromatography

    International Nuclear Information System (INIS)

    Noraini Kasim; Rozita Osman; Norashikin Saim; Licaberth Ismail

    2012-01-01

    Roasting is a critical process in coffee production as it enables the development of flavor and aroma. Benzo[a]pyrene (BaP) is a non desirable product of incomplete combustion at temperatures between 300 and 600 degree Celsius and may be produced during roasting step. In this study, selected samples of roasted coffee powder were analysed for BaP. Extraction of BaP was achieved using C 18 solid phase extraction (SPE) prior to analysis by gas chromatography. Calibration curve prepared with concentrations ranged between 3 - 50 ppm showed good linearity with r = 0.999. The limit of detection (LOD) was 0.25 ppm and the limit of quantification (LOQ) was 0.85 ppm. Recovery of BaP obtained from spiked sample (3 ppm) was 88.7 % with RSD (n=3) of 5.4 %. Benzo[a]pyrene was detected in all samples, at level ranging from 0.14 to 0.62 ppb. (author)

  9. A common carcinogen benzo[a]pyrene causes neuronal death in mouse via microglial activation.

    Directory of Open Access Journals (Sweden)

    Kallol Dutta

    Full Text Available BACKGROUND: Benzo[a]pyrene (B[a]P belongs to a class of polycyclic aromatic hydrocarbons that serve as micropollutants in the environment. B[a]P has been reported as a probable carcinogen in humans. Exposure to B[a]P can take place by ingestion of contaminated (especially grilled, roasted or smoked food or water, or inhalation of polluted air. There are reports available that also suggests neurotoxicity as a result of B[a]P exposure, but the exact mechanism of action is unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using neuroblastoma cell line and primary cortical neuron culture, we demonstrated that B[a]P has no direct neurotoxic effect. We utilized both in vivo and in vitro systems to demonstrate that B[a]P causes microglial activation. Using microglial cell line and primary microglial culture, we showed for the first time that B[a]P administration results in elevation of reactive oxygen species within the microglia thereby causing depression of antioxidant protein levels; enhanced expression of inducible nitric oxide synthase, that results in increased production of NO from the cells. Synthesis and secretion of proinflammatory cytokines were also elevated within the microglia, possibly via the p38MAP kinase pathway. All these factors contributed to bystander death of neurons, in vitro. When administered to animals, B[a]P was found to cause microglial activation and astrogliosis in the brain with subsequent increase in proinflammatory cytokine levels. CONCLUSIONS/SIGNIFICANCE: Contrary to earlier published reports we found that B[a]P has no direct neurotoxic activity. However, it kills neurons in a bystander mechanism by activating the immune cells of the brain viz the microglia. For the first time, we have provided conclusive evidence regarding the mechanism by which the micropollutant B[a]P may actually cause damage to the central nervous system. In today's perspective, where rising pollution levels globally are a matter of grave concern, our

  10. Compartmental analysis of the disposition of benzo[a]pyrene in rats.

    Science.gov (United States)

    Bevan, D R; Weyand, E H

    1988-11-01

    We have previously reported the disposition of benzo[a]pyrene (B[a]P) and its metabolites in male Sprague-Dawley rats following intratracheal instillation of [3H]B[a]P [Weyand, E.H. and Bevan, D.R. (1986) Cancer Res., 46, 5655-5661]. In some experiments, cannulas were implanted in the bile duct of the animals prior to administration of [3H]B[a]P [Weyand, E.H. and Bevan, D.R. (1987) Drug Metab. Disposition, 15, 442-448]. Based on these data, we have developed a compartmental model of the distribution of radioactivity to provide a quantitative description of the fate of B[a]P and its metabolites in rats. Modeling of the distribution of radioactivity was performed using the Simulation, Analysis and Modeling (SAAM) and conversational SAAM (CONSAM) computer programs. Compartments in the model included organs into which the largest amounts of radioactivity were distributed as well as pathways for excretion of radioactivity from the animals. Data from animals with and without cannulas implanted in the bile duct were considered simultaneously during modeling. Radioactivity was so rapidly absorbed from the lungs that an absorption phase into blood was not apparent at the earliest sampling times. Using the model of extrapolate to shorter times, it was predicted that the maximum amount of radioactivity was present in blood within 2 min after administration. In addition, considerable recycling of radioactivity back to lungs from blood was predicted by the model. Transfer of radioactivity from blood to liver and carcass (skin, muscle, bones, fat and associated blood) also was extensive. Carcass was modeled as the sum of two compartments to obtain agreement between the model and experimental data. The model accounted for enterohepatic circulation of B[a]P metabolites; data also required that intestinal secretion be included in the model. Quantitative data obtained from compartmental analysis included rate constants for transfer of radioactivity among compartments as well as

  11. Direct characterization of cotton fabrics treated with di-epoxide by nuclear magnetic resonance.

    Science.gov (United States)

    Xiao, Min; Chéry, Joronia; Keresztes, Ivan; Zax, David B; Frey, Margaret W

    2017-10-15

    A non-acid-based, di-functional epoxide, neopentyl glycol diglycidyl ether (NPGDGE), was used to modify cotton fabrics. Direct characterization of the modified cotton was conducted by Nuclear Magnetic Resonance (NMR) without grinding the fabric into a fine powder. NaOH and MgBr 2 were compared in catalyzing the reaction between the epoxide groups of NPGDGE and the hydroxyl groups of cellulose. Possible reaction routes were discussed. Scanning electron microscopy (SEM) images showed that while the MgBr 2 -catalyzed reaction resulted in self-polymerization of NPGDGE, the NaOH-catalyzed reaction did not. Fourier transform infrared spectroscopy (FTIR) showed that at high NaOH concentration cellulose restructures from allomorph I to II. NMR studies verified the incorporation of NPGDGE into cotton fabrics with a clear NMR signal, and confirmed that at higher NaOH concentration the efficiency of grafting of NPGDGE was increased. This demonstrates that use of solid state NMR directly on woven fabric samples can simultaneously characterize chemical modification and crystalline polymorph of cotton. No loss of tensile strength was observed for cotton fabrics modified with NPGDGE. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. STUDY OF EPOXIDE DECYCLISATION OF CARYOPHYLENE OXIDE WITH SYNTHETIC ZEOLITE AS CATALYSTS

    Directory of Open Access Journals (Sweden)

    Winarto Haryadi

    2010-06-01

    Full Text Available The reaction of epoxide ring opening of caryophillene oxide has been done using zeolite H-Y, H-sodalit, and H-ZSM-5 as catalysts. The reactions were done in two types, there were in dioxane solvent at temperature of 110 oC and without solvent at temperature of 175 oC. The catalyst weight was 10 % from caryophillene oxide weight, and the time of reaction was four hours. The product of reaction was analyzed using GC, FTIR, and GC-MS. The reactions of caryophillene oxide in dioxane solvent with the three kinds of zeolites did not give any targeted product. Whereas, the reactions without solvent gave three main products, there was one compound with one group of secondary hidroxyl (secondary alcohol, and two compounds of ketone from caryophillene. The reaction product of caryophillene oxide obtained without using solvent with the three type of catalysts were then compared. Conversion of three main products produced by H-ZSM-5 catalyst, H-sodalit catalyst and H-Y catalyst were 82.11 %, 54.92 % and 38.53 % respectively. For that reason, the transformation of caryophillene oxide using H-ZSM-5 catalyst was considered to be the best selective product. The alcohol product was resulted from reaction between caryophillene oxide and Bronsted acid, and  the ketone products was resulted from the reaction with Lewis acid in zeolite.   Keywords: Epoxide ring opening, HY, H-sodalit and HZSM-5

  13. Polymerization of Oriental Lacquer (Urushi with Epoxidized Linseed Oil as a New Reactive Diluent

    Directory of Open Access Journals (Sweden)

    Takahisa Ishimura

    2015-01-01

    Full Text Available A hybrid lacquer (HBL paint prepared by combining a natural kurome lacquer (KL paint and an amino silane reagent, for example, N-(2-aminoethyl-3-aminopropyl triethoxysilane (AATES, produced a polymerized film faster than the KL paint alone. However, the viscosity of the HBL paint was too viscous for easy handling. Addition of 10 wt% of an epoxidized linseed oil, ELO-6, with 6.4 mol% epoxidation as a reactive diluent to the HBL paint decreased the viscosity by 1/2 from 25476 mPa·s to 12841 mPa·s and improved the ease of coatability. The polymerization mechanism was elucidated by NMR measurements of extracts from the resulting polymerization films, suggesting that amino groups in the HBL paint reacted with epoxy groups of ELO-6 in the lacquer matrix, and then the complex reacted with double bonds of the urushiol side-chain by autooxidation and cross-linking reactions to give a hard polymerized film with a high quality of color and gloss. These results indicate that the addition of ELO-6 improved the polymerizability of both KL and HBL paints without decreasing the quality of the resulting films.

  14. Development of SBR-Nano clay Composites with Epoxidized Natural Rubber as Compatibilizer

    International Nuclear Information System (INIS)

    Rajasekar, R.; Das, Ch.K.; Gert Heinrich, G.; Das, A.

    2009-01-01

    The significant factor that determines the improvement of properties in rubber by the incorporation of nano clay is its distribution in the rubber matrix. The simple mixing of nonpolar rubber and organically modified nano clay will not contribute for the good dispersion of nano filler in the rubbery matrix. Hence a polar rubber like epoxidized natural rubber (ENR) can be used as a compatibilizer in order to obtain a better dispersion of the nano clay in the matrix polymer. Epoxidized natural rubber and organically modified nano clay composites (EC) were prepared by solution mixing. The nano clay employed in this study is Cloisite 20A. The obtained nano composites were incorporated in styrene butadiene-rubber (SBR) compounds with sulphur as a curing agent. The morphology observed through X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) shows that the nano clay is highly intercalated in ENR, and further incorporation of EC in SBR matrix leads to partial exfoliation of the nano clay. Dynamic mechanical thermal analysis showed an increase in storage modulus and lesser damping characteristics for the compounds containing EC loading in SBR matrix. In addition, these compounds showed improvement in the mechanical properties.

  15. Aerobic methylcyclohexane-promoted epoxidation of stilbene over gold nanoparticles supported on Gd-doped titania

    KAUST Repository

    Mendez, Violaine; Guillois, Kevin; Daniè le, Sté phane; Tuel, Alain; Caps, Valerie

    2010-01-01

    Aerobic partial oxidations of alkanes and alkenes are important processes of the petrochemical industry. The radical mechanisms involved can be catalyzed by soluble salts of transition metals (Co, Cu, Mn...). We show here that the model methylcyclohexane/stilbene co-oxidation reaction can be efficiently catalyzed at lower temperature by supported gold nanoparticles. The support has little influence on gold intrinsic activity but more on the apparent reaction rates which are a combination of catalytic activity and diffusion limitations. These are here minimized by using gadolinium-doped titania nanocrystallites as support for gold nanoparticles. This material is obtained by mild hydrolysis of a new Gd4TiO(OiPr)14 bimetallic oxoalkoxide. It leads to enhanced wettability of the < 3 nm gold particles in the tert-butyl hydroperoxide (TBHP)-initiated epoxidation of stilbene in methylcyclohexane; Au/TiO2:Gd3+ is in turn as active as the state-of-the-art hydrophobic Au/SiO2 catalyst. The rate-determining step of this reaction is identified as the gold-catalyzed homolytic decomposition of TBHP generating radicals and initiating the methylcyclohexane-mediated epoxidation of stilbene, yielding a methylcyclohexan-1-ol/trans-stilbene oxide mixture. Methylcyclohexan-1-ol can also be obtained in the absence of the alkene in the gold-catalyzed solvent-free autoxidation of methylcyclohexane, evidencing the catalytic potential of gold nanoparticles for low temperature C-H activation. © 2010 The Royal Society of Chemistry.

  16. Mechanistic aspects of the metal catalyzed alternating copolymerization of epoxides and carbon monoxide.

    Science.gov (United States)

    Allmendinger, Markus; Molnar, Ferenc; Zintl, Manuela; Luinstra, Gerrit A; Preishuber-Pflügl, Peter; Rieger, Bernhard

    2005-09-05

    The cobalt-catalyzed alternating copolymerization of epoxides and CO is a novel, direct approach to aliphatic polyesters, such as poly(hydroxybutyrate) (PHB). This reaction was found to be catalyzed by Ph3Si[Co(CO)4] (4) and pyridine affording in a first step the stable mono-insertion product Ph3Si-O-CH(CH3)-CH2-CO-Co(CO)4 (5). However, a profound mechanistic understanding, especially of the role of pyridine as the key component for the polymerization reaction was missing. ATR-IR online monitoring under catalytic conditions and DFT calculations were used to show that an acylpyridinium cation is formed by cleavage of the cobalt-acyl bond of 5 in the presence of pyridine. The Lewis acid thus generated activates the next incoming epoxide monomer for ring opening through [Co(CO)4]-. The catalytic cycle is completed by a subsequent CO insertion in the new cobalt-alkyl bond. The calculations are used to explore the energetic hypersurface of the polymerization reaction and are complemented by extended experimental investigations that also support the mechanistic hypotheses.

  17. MWCNTs-reinforced epoxidized linseed oil plasticized polylactic acid nanocomposite and its electroactive shape memory behaviour.

    Science.gov (United States)

    Alam, Javed; Alam, Manawwer; Raja, Mohan; Abduljaleel, Zainularifeen; Dass, Lawrence Arockiasamy

    2014-10-31

    A novel electroactive shape memory polymer nanocomposite of epoxidized linseed oil plasticized polylactic acid and multi-walled carbon nanotubes (MWCNTs) was prepared by a combination of solution blending, solvent cast technique, and hydraulic hot press moulding. In this study, polylactic acid (PLA) was first plasticized by epoxidized linseed oil (ELO) in order to overcome the major limitations of PLA, such as high brittleness, low toughness, and low tensile elongation. Then, MWCNTs were incorporated into the ELO plasticized PLA matrix at three different loadings (2, 3 and 5 wt. %), with the aim of making the resulting nanocomposites electrically conductive. The addition of ELO decreased glass transition temperature, and increased the elongation and thermal degradability of PLA, as shown in the results of differential scanning calorimetry (DSC), tensile test, and thermo gravimetric analysis (TGA). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe surface morphology, topography, and the dispersion of MWCNTs in the nanocomposite. Finally, the electroactive-shape memory effect (electroactive-SME) in the resulting nanocomposite was investigated by a fold-deploy "U"-shape bending test. As per the results, the addition of both ELO and MWCNTs to PLA matrix seemed to enhance its overall properties with a great deal of potential in improved shape memory. The 3 wt. % MWCNTs-reinforced nanocomposite system, which showed 95% shape recovery within 45 s at 40 DC voltage, is expected to be used as a preferential polymeric nanocomposite material in various actuators, sensors and deployable devices.

  18. MWCNTs-Reinforced Epoxidized Linseed Oil Plasticized Polylactic Acid Nanocomposite and Its Electroactive Shape Memory Behaviour

    Directory of Open Access Journals (Sweden)

    Javed Alam

    2014-10-01

    Full Text Available A novel electroactive shape memory polymer nanocomposite of epoxidized linseed oil plasticized polylactic acid and multi-walled carbon nanotubes (MWCNTs was prepared by a combination of solution blending, solvent cast technique, and hydraulic hot press moulding. In this study, polylactic acid (PLA was first plasticized by epoxidized linseed oil (ELO in order to overcome the major limitations of PLA, such as high brittleness, low toughness, and low tensile elongation. Then, MWCNTs were incorporated into the ELO plasticized PLA matrix at three different loadings (2, 3 and 5 wt. %, with the aim of making the resulting nanocomposites electrically conductive. The addition of ELO decreased glass transition temperature, and increased the elongation and thermal degradability of PLA, as shown in the results of differential scanning calorimetry (DSC, tensile test, and thermo gravimetric analysis (TGA. Scanning electron microscopy (SEM and atomic force microscopy (AFM were used to observe surface morphology, topography, and the dispersion of MWCNTs in the nanocomposite. Finally, the electroactive-shape memory effect (electroactive-SME in the resulting nanocomposite was investigated by a fold-deploy “U”-shape bending test. As per the results, the addition of both ELO and MWCNTs to PLA matrix seemed to enhance its overall properties with a great deal of potential in improved shape memory. The 3 wt. % MWCNTs-reinforced nanocomposite system, which showed 95% shape recovery within 45 s at 40 DC voltage, is expected to be used as a preferential polymeric nanocomposite material in various actuators, sensors and deployable devices.

  19. Precursor effect on the property and catalytic behavior of Fe-TS-1 in butadiene epoxidation

    Science.gov (United States)

    Wu, Mei; Zhao, Huahua; Yang, Jian; Zhao, Jun; Song, Huanling; Chou, Lingjun

    2017-11-01

    The effect of iron precursor on the property and catalytic behavior of iron modified titanium silicalite molecular sieve (Fe-TS-1) catalysts in butadiene selective epoxidation has been studied. Three Fe-TS-1 catalysts were prepared, using iron nitrate, iron chloride and iron sulfate as precursors, which played an important role in adjusting the textural properties and chemical states of TS-1. Of the prepared Fe-TS-1 catalysts, those modified by iron nitrate (FN-TS-1) exhibited a significant enhanced performance in butadiene selective epoxidation compared to those derived from iron sulfate (FS-TS-1) or iron chloride (FC-TS-1) precursors. To obtain a deep understanding of their structure-performance relationship, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Temperature programmed desorption of NH3 (NH3-TPD), Diffuse reflectance UV-Vis spectra (DR UV-Vis), Fourier transformed infrared spectra (FT-IR) and thermal gravimetric analysis (TGA) were conducted to characterize Fe-TS-1 catalysts. Experimental results indicated that textural structures and acid sites of modified catalysts as well as the type of Fe species influenced by the precursors were all responsible for the activity and product distribution.

  20. Surface science study of selective ethylene epoxidation catalyzed by the Ag(110) surface: Structural sensitivity

    International Nuclear Information System (INIS)

    Campbell, C.T.

    1984-01-01

    The selective oxidation of ethylene to ethylene epoxide (C 2 H 4 +1/2O 2 →C 2 H 4 O) over Ag is the simplest example of kinetically controlled, selective heterogeneous catalysis. We have studied the steady-state kinetics and selectivity of this reaction for the first time on a clean, well-characterized Ag(110) surface by using a special apparatus which allows rapid (approx.20 s) transfer between a high-pressure catalytic microreactor and an ultrahigh vacuum surface analysis (AES, XPS, LEED, TDS) chamber. The effects of temperature and reactant pressures upon the rate and selectivity are virtually identical on Ag(110) and supported, high surface area Ag catalysts. The absolute specific rate (per Ag surface atom) is, however, some 100-fold higher for Ag(110) than for high surface area catalysts. This is related to the well-known structural sensitivity of this reaction. It is postulated that a small percentage of (110) planes (or [110]-like sites) are responsible for most of the catalytic activity of high surface area catalysts. The high activity of the (110) plane is attributed to its high sticking probability for dissociative oxygen adsorption, since the rate of ethylene epoxidation is shown in a related work [Ref. 1: C. T. Campbell and M. T. Paffett, Surf. Sci. (in press)] to be proportional to the coverage of atomically adsorbed oxygen at constant temperature and ethylene pressure

  1. Epoxides cross-linked hexafluoropropylidene polybenzimidazole membranes for application as high temperature proton exchange membranes

    International Nuclear Information System (INIS)

    Yang, Jingshuai; Xu, Yixin; Liu, Peipei; Gao, Liping; Che, Quantong; He, Ronghuan

    2015-01-01

    Covalently cross-linked hexafluoropropylidene polybenzimidazole (F 6 PBI) was prepared and used to fabricate high temperature proton exchange membranes with enhanced mechanical strength against thermoplastic distortion. Three different epoxides, i.e. bisphenol A diglycidyl ether (R 1 ), bisphenol A propoxylate diglycidyl ether (R 2 ) and poly(ethylene glycol) diglycidyl ether (R 3 ), were chosen as the cross-linkers to investigate the influence of their structures on the properties of the cross-linked F 6 PBI membranes. All the cross-linked F 6 PBI membranes displayed excellent stability towards the radical oxidation. Comparing with the pure F 6 PBI membrane, the cross-linked F 6 PBI membranes showed high acid doping level but less swelling after doping phosphoric acid at elevated temperatures. The mechanical strength at 130 °C was improved from 0.4 MPa for F 6 PBI membrane to a range of 0.8–2.0 MPa for the cross-linked F 6 PBI membranes with an acid doping level as high as around 14, especially for that crosslinking with the epoxide (R 3 ), which has a long linear structure of alkyl ether. The proton conductivity of the cross-linked membranes was increased accordingly due to the high acid doping levels. Fuel cell tests demonstrated the technical feasibility of the acid doped cross-linked F 6 PBI membranes for high temperature proton exchange membrane fuel cells

  2. Letter to the Editor: About "Studies of Viscosity and Excess Molar Volume of Binary Mixtures of Propane-1,2 diol with Water at Various Temperatures"

    Czech Academy of Sciences Publication Activity Database

    Linek, Jan

    2003-01-01

    Roč. 208, 1-2 (2003), s. 261-263 ISSN 0378-3812 R&D Projects: GA ČR GA203/02/1098 Institutional research plan: CEZ:AV0Z4072921 Keywords : water * propane-1,2-diol * physical properties Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.165, year: 2003

  3. (E-2-((4R,5R-5-((Benzyloxymethyl-2,2-dimethyl-1,3-dioxolan-4-ylbut-2-ene-1,4-diol

    Directory of Open Access Journals (Sweden)

    Carlos R. Carreras

    2010-04-01

    Full Text Available The synthesis of (E-2-((4R,5R-5-((benzyloxymethyl-2,2-dimethyl-1,3-dioxolan-4-ylbut-2-ene-1,4-diol by a one-step reduction of the appropriate 2-substituted butenolide is reported. Product characterization was carried out by IR, 1H NMR, 13C NMR, MS, elemental analysis and optical rotation.

  4. Synthesis and thermal behavior of telechelic poly(butadiene)diols with azobenzene-based liquid-crystalline units in side chains

    Czech Academy of Sciences Publication Activity Database

    Poláková, Lenka; Sedláková, Zdeňka; Látalová, Petra

    2010-01-01

    Roč. 64, č. 4 (2010), s. 315-326 ISSN 0170-0839 R&D Projects: GA ČR GA202/09/2078 Institutional research plan: CEZ:AV0Z40500505 Keywords : azobenzene mesogens * radical addition * poly(butadiene)diols Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.215, year: 2010

  5. High-Throughput Assay for Enantiomeric Excess Determination in 1,2- and 1,3-Diols and Direct Asymmetric Reaction Screening.

    Science.gov (United States)

    Shcherbakova, Elena G; Brega, Valentina; Lynch, Vincent M; James, Tony D; Anzenbacher, Pavel

    2017-07-26

    A simple and efficient method for determination of the yield, enantiomeric/diasteriomeric excess (ee/de), and absolute configuration of crude chiral diols without the need of work-up and product isolation in a high throughput setting is described. This approach utilizes a self-assembled iminoboronate ester formed as a product by dynamic covalent self-assembly of a chiral diol with an enantiopure fluorescent amine such as tryptophan methyl ester or tryptophanol and 2-formylphenylboronic acid. The resulting diastereomeric boronates display different photophysical properties and allow for fluorescence-based ee determination of molecules containing a 1,2- or 1,3-diol moiety. This method has been utilized for the screening of ee in a number of chiral diols including atorvastatin, a statin used for the treatment of hypercholesterolemia. Noyori asymmetric hydrogenation of benzil was performed in a highly parallel fashion with errors products from the parallel asymmetric synthesis in real time and in a high-throughput screening (HTS) fashion. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Chiral separation of synthetic vicinal diol compounds by capillary zone electrophoresis with borate buffer and beta-cyclodextrin as buffer additive.

    Science.gov (United States)

    Zhao, Yan; Yang, Xingbin; Jiang, Ru; Sun, Xiaoli; Liu, Wenmin; Zhang, Shengyong

    2006-05-01

    The investigation on capillary electrophoretic enantioseparation of six synthetic compounds containing vicinal diol groups has been undertaken to acquire the optimum conditions using native beta-cyclodextrin (beta-CD) as chiral selector and borate as a background electrolyte. The separation was carried out in an uncoated capillary (58.5 cm x 75 microm i.d., effective length 48.5 cm) and the effects of several important factors were investigated in detail. The results showed that beta-CD as a chiral selector exhibited good enantioselectivity and that the enantioseparation was greatly influenced by the structure of the diols, the borate concentration and the buffer pH. The optimum performance was obtained for the chiral vicinal diols under the conditions of 200 mM borate buffer of pH 9.8 containing 1.7% beta-CD at an applied voltage of 15 kV and a capillary temperature of 20 degrees C. Under the conditions, four diols were baseline separated with fast analysis time and the good theoretical plate numbers (above 10 x 10(4)) and favorable migration-time reproducibilities (RSDs below 3.0%) were obtained. The separation results were satisfactory.

  7. Glass transition and the rigid amorphous phase in semicrystalline blends of bacterial polyhydroxybutyrate PHB with low molecular mass atactic R,S-PHB-diol

    NARCIS (Netherlands)

    Hoehne, G.W.H.

    2004-01-01

    The glass transition and the crystallinity of blends of isotactic bacterial PHB and low molecular mass atactic R, S-PHB-diols was investigated by means of differential scanning calorimetry (DSC), temperature-modulated DSC and dielectric spectroscopy. It was found that (i) Tg of crystallized blends

  8. Speed of sound in saturated aliphatic alcohols (propan-2-ol, butan-2-ol, and 2-methylpropan-1-ol) and alkanediols (ethane-1,2-diol, propane-1,2- and -1,3-diol) at temperature between 253.15 K and 353.15 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Dávila, María J.; Gedanitz, Holger; Span, Roland

    2016-01-01

    Highlights: • Speed of sound measurements were made in aliphatic alcohols and alkanediols. • Speeds of sound were measured in a wide temperature and pressure range. • A pulse-echo method with a double path type sensor operating at 8 MHz was employed. • A double polynomial equation was used to fit the experimental speed of sound data. • The accurate results were compared with available literature sources. - Abstract: Speeds of sound have been measured in three saturated aliphatic alcohols (propan-2-ol, butan-2-ol, and 2-methylpropan-1-ol) and three alkanediols (ethane-1,2-diol, propane-1,2- and -1,3-diol) in the temperature range from (253.15 to 353.15) K and pressures up to 30 MPa by use of a pulse-echo method with a double path type sensor operating at 8 MHz. The expanded overall uncertainties (k = 2) in the speed of sound measurements are estimated to be 0.013% for propan-2-ol, 0.019% for butan-2-ol, 0.01% for 2-methylpropan-1-ol, 0.009% for ethane-1,2-diol, 0.02% for propane-1,2-diol, and 0.07% for propane-1,3-diol. Experimental speeds of sound data were correlated with the temperature and pressure with an empirical double polynomial equation. Our results were also compared with the available literature data and a satisfactory agreement was found.

  9. Highly Sensitive Determination of 2,4,6-Trinitrotoluene and Related Byproducts Using a Diol Functionalized Column for High Performance Liquid Chromatography

    Science.gov (United States)

    Gumuscu, Burcu; Erdogan, Zeynep; Guler, Mustafa O.; Tekinay, Turgay

    2014-01-01

    In this work, a new detection method for complete separation of 2,4,6-trinitrotoluene (TNT); 2,4-dinitrotoluene (2,4-DNT); 2,6-dinitrotoluene (2,6-DNT); 2-aminodinitrotoluene (2-ADNT) and 4-aminodinitrotoluene (4-ADNT) molecules in high-performance liquid-chromatography (HPLC) with UV sensor has been developed using diol column. This approach improves on cost, time, and sensitivity over the existing methods, providing a simple and effective alternative. Total analysis time was less than 13 minutes including column re-equilibration between runs, in which water and acetonitrile were used as gradient elution solvents. Under optimized conditions, the minimum resolution between 2,4-DNT and 2,6-DNT peaks was 2.06. The recovery rates for spiked environmental samples were between 95–98%. The detection limits for diol column ranged from 0.78 to 1.17 µg/L for TNT and its byproducts. While the solvent consumption was 26.4 mL/min for two-phase EPA and 30 mL/min for EPA 8330 methods, it was only 8.8 mL/min for diol column. The resolution was improved up to 49% respect to two-phase EPA and EPA 8330 methods. When compared to C-18 and phenyl-3 columns, solvent usage was reduced up to 64% using diol column and resolution was enhanced approximately two-fold. The sensitivity of diol column was afforded by the hydroxyl groups on polyol layer, joining the formation of charge-transfer complexes with nitroaromatic compounds according to acceptor-donor interactions. Having compliance with current requirements, the proposed method demonstrates sensitive and robust separation. PMID:24905826

  10. Highly sensitive determination of 2,4,6-trinitrotoluene and related byproducts using a diol functionalized column for high performance liquid chromatography.

    Science.gov (United States)

    Gumuscu, Burcu; Erdogan, Zeynep; Guler, Mustafa O; Tekinay, Turgay

    2014-01-01

    In this work, a new detection method for complete separation of 2,4,6-trinitrotoluene (TNT); 2,4-dinitrotoluene (2,4-DNT); 2,6-dinitrotoluene (2,6-DNT); 2-aminodinitrotoluene (2-ADNT) and 4-aminodinitrotoluene (4-ADNT) molecules in high-performance liquid-chromatography (HPLC) with UV sensor has been developed using diol column. This approach improves on cost, time, and sensitivity over the existing methods, providing a simple and effective alternative. Total analysis time was less than 13 minutes including column re-equilibration between runs, in which water and acetonitrile were used as gradient elution solvents. Under optimized conditions, the minimum resolution between 2,4-DNT and 2,6-DNT peaks was 2.06. The recovery rates for spiked environmental samples were between 95-98%. The detection limits for diol column ranged from 0.78 to 1.17 µg/L for TNT and its byproducts. While the solvent consumption was 26.4 mL/min for two-phase EPA and 30 mL/min for EPA 8330 methods, it was only 8.8 mL/min for diol column. The resolution was improved up to 49% respect to two-phase EPA and EPA 8330 methods. When compared to C-18 and phenyl-3 columns, solvent usage was reduced up to 64% using diol column and resolution was enhanced approximately two-fold. The sensitivity of diol column was afforded by the hydroxyl groups on polyol layer, joining the formation of charge-transfer complexes with nitroaromatic compounds according to acceptor-donor interactions. Having compliance with current requirements, the proposed method demonstrates sensitive and robust separation.

  11. Highly sensitive determination of 2,4,6-trinitrotoluene and related byproducts using a diol functionalized column for high performance liquid chromatography.

    Directory of Open Access Journals (Sweden)

    Burcu Gumuscu

    Full Text Available In this work, a new detection method for complete separation of 2,4,6-trinitrotoluene (TNT; 2,4-dinitrotoluene (2,4-DNT; 2,6-dinitrotoluene (2,6-DNT; 2-aminodinitrotoluene (2-ADNT and 4-aminodinitrotoluene (4-ADNT molecules in high-performance liquid-chromatography (HPLC with UV sensor has been developed using diol column. This approach improves on cost, time, and sensitivity over the existing methods, providing a simple and effective alternative. Total analysis time was less than 13 minutes including column re-equilibration between runs, in which water and acetonitrile were used as gradient elution solvents. Under optimized conditions, the minimum resolution between 2,4-DNT and 2,6-DNT peaks was 2.06. The recovery rates for spiked environmental samples were between 95-98%. The detection limits for diol column ranged from 0.78 to 1.17 µg/L for TNT and its byproducts. While the solvent consumption was 26.4 mL/min for two-phase EPA and 30 mL/min for EPA 8330 methods, it was only 8.8 mL/min for diol column. The resolution was improved up to 49% respect to two-phase EPA and EPA 8330 methods. When compared to C-18 and phenyl-3 columns, solvent usage was reduced up to 64% using diol column and resolution was enhanced approximately two-fold. The sensitivity of diol column was afforded by the hydroxyl groups on polyol layer, joining the formation of charge-transfer complexes with nitroaromatic compounds according to acceptor-donor interactions. Having compliance with current requirements, the proposed method demonstrates sensitive and robust separation.

  12. In vitro investigations of α-amylase mediated hydrolysis of cyclodextrins in the presence of ibuprofen, flurbiprofen, or benzo[a]pyrene

    DEFF Research Database (Denmark)

    Riisager, Ludmilla Lumholdt; Holm, R.; Jørgensen, E. B.

    2012-01-01

    -γ-cyclodextrins have different biopharmaceutical behaviours than the other evaluated cyclodextrins. The rate of degradation was affected by the addition of the inclusion complex forming additives flurbiprofen, ibuprofen and benzo[a]pyrene. This effect between the degradation dynamics and the included additives...

  13. Factors controlling benzo(a)pyrene concentration in aerosols in the urbanized coastal zone. A case study: Gdynia, Poland (Southern Baltic Sea).

    Science.gov (United States)

    Staniszewska, Marta; Graca, Bożena; Bełdowska, Magdalena; Saniewska, Dominika

    2013-06-01

    Annual study on the benzo(a)pyrene (BaP) concentration in aerosols in the coastal zone of the Gulf of Gdansk (southern Baltic) has been performed at Gdynia station. Combustion processes, especially domestic heating of both local and regional origin, were identified as the main sources of benzo(a)pyrene in this area. Concentrations observed during the heating season (mean 2.18 ng m(-3)) were significantly higher than these recorded in the non-heating season (mean 0.05 ng m(-3)). High benzo(a)pyrene concentrations were associated with low temperature and high humidity. Whereas high levels of precipitation usually decreased the BaP concentration in aerosols. The concentration of this factor in the studied area depended also on the wind direction and air masses trajectories. During heating season, continental air masses (coming from S, SE, SW) seemed to increase benzo(a)pyrene concentration, while maritime air masses (from N, NE, NW) caused its decrease. The differences in the BaP concentration resulting from potentially different emission levels of this compound during working and non-working days were not clearly pronounced.

  14. Metabolism of benzo(a)pyrene and 7,12-dimethylbenz(a)anthracene in cultured human bronchus and pancreatic duct

    DEFF Research Database (Denmark)

    Harris, Curtis C.; Autrup, Herman; Stoner, Gary

    1977-01-01

    The metabolism of two carcinogenic polynuclear aro matic hydrocarbons, benzo[a]pyrene (BP) and 7,12-dimethylbenz[a]anthracene, was studied in expiants of human pancreatic duct and bronchus cultured in a chemically defined medium. In cultured human bronchial mucosa, activity of aryl hydrocarbon hy...

  15. Metabolism of benzo(a)pyrene and identification of the major benzo(a)pyrene-DNA adducts in cultured human colon

    DEFF Research Database (Denmark)

    Autrup, Herman; Harris, Curtis C.; Trump, Benjamin F.

    1978-01-01

    The metabolism of benzo(a)pyrene in cultured human colon has been investigated. Nontumorous colonie tissue was collected at the time of either surgery or "immediate autopsy" from patients with or without colonic cancer. After 24 hr in culture the expiants were exposed to [3H]benzo(a)pyrene for an...

  16. Aerobic Epoxidation of Olefins Catalyzed by the Cobalt‐Based Metal–Organic Framework STA‐12(Co)

    DEFF Research Database (Denmark)

    Beier, Matthias Josef; Kleist, Wolfgang; Wharmby, Michael T.

    2012-01-01

    , (E)‐stilbene was converted with high selectivities between 80 and 90 %. Leaching of Co was low and the reaction was found to proceed mainly heterogeneously. The catalyst was reusable with only a small loss of activity. The catalytic epoxidation of stilbene with the MOF featured an induction period...

  17. (Salen)Ti(Ⅳ)-Catalyzed Asymmetric Ring-opening of meso Epoxides Using Dithiophosphorus Acid as the Nucleophile

    Institute of Scientific and Technical Information of China (English)

    Zheng Hong ZHOU; Zhao Ming LI; Bing LIU; Kang Ying LI; Li Xin WANG; Guo Feng ZHAO; Qi Lin ZHOU; Chu Chi TANG

    2006-01-01

    The asymmetric ring-opening of epoxides with dithiophosphorus acids catalyzed by a (salen)Ti(Ⅳ) complex formed in situ from the reaction of Ti(OPr-i)4 and the chiral Schiff base derived from (1R,2R)-(+)-diaminocyclohexane was realized. The resulting products were obtained with low to good enantioselectivity (up to 73% ee).

  18. Organic carbonates as solvents in macrocyclic Mn(III) salen catalyzed asymmetric epoxidation of non-functionalized olefins

    Czech Academy of Sciences Publication Activity Database

    Maity, N. Ch.; Rao, G. V. S.; Prathap, Kaniraj Jeya; Abdi, S. H. R.; Kureshy, R. I.; Khan, N. H.; Bajaj, H. C.

    2013-01-01

    Roč. 366, January (2013), s. 380-389 ISSN 1381-1169 Institutional support: RVO:61388963 Keywords : asymmetric epoxidation * organic carbonate * macrocyclic Mn(III) salen complex Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.679, year: 2013

  19. Combination of supramolecular cross-linking with covalent cross-linking through epoxide ring-opening including gel studies

    NARCIS (Netherlands)

    Hofmeier, H.; El-Ghayoury, A.; Schubert, U.S.

    2003-01-01

    Terpolymers based on poly(methyl methacrylate), containing terpyridine-moieties as well as epoxide groups, were synthesized via free-radical polymeri-zation. The products were cross-linked non-covalently with iron(II) ions and cova-lently by treatment with AlCl3. Both steps could be combined in

  20. Combination of supramolecular cross-linking with covalent cross-linking through epoxide ring-opening including gel studies

    NARCIS (Netherlands)

    Hofmeier, H.; El-Ghayoury, A.; Schubert, U.S.

    2003-01-01

    Terpolymers based on poly(methyl methacrylate), containing terpyridinemoieties as well as epoxide groups, were synthesized via free-radical polymerization. The products were cross-linked non-covalently with iron(II) ions and covalently by treatment with AlCl3. Both steps could be combined in

  1. Anhydrous ZnCl2: A Highly Efficient Reagent for Facile and Regioselective Conversion of Epoxides to β-Chlorohydrins

    Directory of Open Access Journals (Sweden)

    Ronak Eisavi

    2016-01-01

    Full Text Available Facile conversion of structurally different epoxides to the corresponding β-chlorohydrins was carried out successfully with anhydrous ZnCl2 in CH3CN. The reactions were carried out within 10-50 min to give β-chlorohydrins with perfect regioselectivity and high yields (80-97%.

  2. Synthesis, Characterizations and Investigation of Electrochemical Behaviours of 4-[(2-Hydroxyphenyliminomethyl]benzene-1,3-diol

    Directory of Open Access Journals (Sweden)

    Aysen D. Mulazimoglu

    2009-01-01

    Full Text Available This Schiff base ligand, 4-[(2-hydroxyphenylimino methyl]benzene-1,3-diol (HIBD was synthesized by reaction of 2-aminophenol and 2,4-dihydroxybenzaldehyde. The ligand was characterized by elemental analysis, FT-IR and 1H-NMR. Electrochemical behaviors were investigated on the glassy carbon electrode (GC surface with cyclic voltammetry (CV. The modification of HIBD on the GC was performed in +0.3 V and +2,8 V potential range using 100 mV s-1 scanning rate having 5 cycle. For the characterization of the modified surfaces 1 mM ferrocene redox probe in 0,1 M tetrabutylammonium tetrafluoroborate (TBATFB and 1 mM ferricyanide redox probe in 0.1 M H2SO4 were used.

  3. Formation and reduction of 3-monochloropropane-1,2-diol esters in peanut oil during physical refining.

    Science.gov (United States)

    Li, Chang; Li, Linyan; Jia, Hanbing; Wang, Yuting; Shen, Mingyue; Nie, Shaoping; Xie, Mingyong

    2016-05-15

    In the present study, lab-scale physical refining processes were investigated for their effects on the formation of 3-monochloropropane-1,2-diol (3-MCPD) esters. The potential precursors, partial acylglycerols and chlorines were determined before each refining step. 3-MCPD esters were not detected in degummed and bleached oil when the crude oils were extracted by solvent. While in the hot squeezed crude oils, 3-MCPD esters were detected with low amounts. 3-MCPD esters were generated with maximum values in 1-1.5h at a certain deodorizing temperature (220-260°C). Chlorine seemed to be more effective precursor than partial acylglycerol. By washing bleached oil before deodorization with ethanol solution, the precursors were removed partially and the content of 3-MCPD esters decreased to some extent accordingly. Diacetin was found to reduce 3-MCPD esters effectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Occurrence of 3-chloro-propane-1,2-diol (3-MCPD) and related compounds in foods: a review.

    Science.gov (United States)

    Hamlet, C G; Sadd, P A; Crews, C; Velísek, J; Baxter, D E

    2002-07-01

    A critical review of the occurrence of 3-chloro-propane-1,2-diol (3-MCPD) in foods not known to contain hydrolysed vegetable proteins is presented. The review covers the properties and chemistry of 3-MCPD and the current methods of analysis in foodstuffs. The results of UK surveys of 3-MCPD occurrence in both retail foods and commercial food ingredients are discussed with particular reference to cereal, meat and dairy products. The possible mechanisms for the formation and decay of 3-MCPD in foods are suggested. The review does not cover the detailed toxicology of 3-MCPD and its occurrence in hydrolysed vegetable proteins, which have been considered elsewhere, nor possible issues such as in-vivo formation.

  5. Modeling of Toxicity-Relevant Electrophilic Reactivity for Guanine with Epoxides: Estimating the Hard and Soft Acids and Bases (HSAB) Parameter as a Predictor.

    Science.gov (United States)

    Zhang, Jing; Wang, Chenchen; Ji, Li; Liu, Weiping

    2016-05-16

    According to the electrophilic theory in toxicology, many chemical carcinogens in the environment and/or their active metabolites are electrophiles that exert their effects by forming covalent bonds with nucleophilic DNA centers. The theory of hard and soft acids and bases (HSAB), which states that a toxic electrophile reacts preferentially with a biological macromolecule that has a similar hardness or softness, clarifies the underlying chemistry involved in this critical event. Epoxides are hard electrophiles that are produced endogenously by the enzymatic oxidation of parent chemicals (e.g., alkenes and PAHs). Epoxide ring opening proceeds through a SN2-type mechanism with hard nucleophile DNA sites as the major facilitators of toxic effects. Thus, the quantitative prediction of chemical reactivity would enable a predictive assessment of the molecular potential to exert electrophile-mediated toxicity. In this study, we calculated the activation energies for reactions between epoxides and the guanine N7 site for a diverse set of epoxides, including aliphatic epoxides, substituted styrene oxides, and PAH epoxides, using a state-of-the-art density functional theory (DFT) method. It is worth noting that these activation energies for diverse epoxides can be further predicted by quantum chemically calculated nucleophilic indices from HSAB theory, which is a less computationally demanding method than the exacting procedure for locating the transition state. More importantly, the good qualitative/quantitative correlations between the chemical reactivity of epoxides and their bioactivity suggest that the developed model based on HSAB theory may aid in the predictive hazard evaluation of epoxides, enabling the early identification of mutagenicity/carcinogenicity-relevant SN2 reactivity.

  6. Exploring Lactobacillus reuteri DSM20016 as a biocatalyst for transformation of longer chain 1,2-diols: Limits with microcompartment.

    Science.gov (United States)

    Chen, Lu; Hatti-Kaul, Rajni

    2017-01-01

    Lactobacillus reuteri metabolises glycerol efficiently to form 3-hydroxypropionic acid (3-HP) and 1,3-propanediol (1,3PDO) by the same mechanism as that for 1,2-propanediol (1,2PDO) conversion to propionic acid and propanol via its propanediol utilization (pdu) pathway. Pdu enzymes are encoded by the pdu-operon, which also contain genes encoding the shell proteins of the microcompartment housing the metabolic pathway. In this work the selectivity and kinetics of the reactions catalysed by L. reuteri DSM20016 Pdu enzymes glycerol dehydratase (GDH), 1,3-propanediol oxidoreductase (PduQ) and coenzyme-A acylating propionaldehyde dehydrogenase (PduP), produced recombinantly, was investigated against corresponding substrates of different chain lengths. Glycerol dehydratase exhibited activity against C2-C4 polyols, with the highest activity against glycerol and 1,2-propanediol (1,2-PDO). A double mutant of the pduC gene of GDH (PduC-S302A/Q337A) was constructed that displayed lowered activity against glycerol and 1,2PDO but extended the substrate range upto C6-diol. The best substrate for both PduQ and PduP was 3-hydroxypropanal (3HPA), although PduP exhibited nearly 10-fold higher specific activity. The enzymes also showed some activity against C3-C10 aliphatic aldehydes, with PduP having higher relative activity. Subsequently, transformation of polyols using whole cells of L. reuteri containing the wild type- and mutated GDH, respectively, confirmed the reduced activity of the mutant against glycerol and 1,2PDO, but its activity against longer substrates was negligible. In contrast, recombinant Escherichia coli BL21(DE3) cells harboring the GDH variant converted diols with up to C6 carbon chain length to their respective aldehydes, suggesting that the protein shell of the microcompartment in L. reuteri posed a barrier to the passage of longer chain substrate.

  7. Si-Imidazole-HSO4 Functionalized Magnetic Fe3O4 Nanoparticles as an Efficient and Reusable Catalyst for the Regioselective Ring Opening of Epoxides in Water

    Directory of Open Access Journals (Sweden)

    Eshagh Rezaee Nezhad

    2016-01-01

    Full Text Available An efficient and simple method for the preparation of Si-Imidazole-HSO4 functionalized magnetic Fe3O4 nanoparticles (Si-Im-HSO4 MNPs and used as an efficient and reusable magnetic catalysts for the regioselective ring opening of epoxides under green conditions in water. This catalyst was used for the ring opening of epoxide corresponding to the thiocyanohydrins and azidohydrines. Compared to the classical ring opening of epoxides, this new method consistently has the advantage of excellent yields, short reaction times, and methodological simplicity.

  8. Combination of natural fiber Boehmeria nivea (ramie) with matrix epoxide for bullet proof vest body armor

    Energy Technology Data Exchange (ETDEWEB)

    Anggoro, Didi Dwi, E-mail: anggorophd@gmail.com; Kristiana, Nunung, E-mail: nuna.c631@gmail.com [Master of Chemical Engineering, Faculty of Engineering, Diponegoro University Jln. Prof. Sudharto, Tembalang, Semarang, 50239 (Indonesia)

    2015-12-29

    Ballistic protection equipment, such as a bulletproof vest, is a soldier’s most important means of preserving life and survivability in extreme combat conditions. The bulletproof vests are designed to protect the user’s chest from injury without disturbing the ability to perform his duties. Aromatic polyamide or aramid fibers known under the trade name Kevlar, Trawon and so is synthetic fiber materials commonly used in the manufacture of bulletproof vests. This synthetic fibers have high tensile strength and ductility. Kevlar is expensive and imported material. In this study, will introduce local natural raw materials, ramie fiber (Boehmeria nivea) which is cheaper and environmentally friendly. It has enough tenacity and tensile strength as a bulletproof vest. This experiment uses two panels, there are Panel A as front surface of Panel B. Panel A is a combination of ramie and epoxide matrix, while panel B is only ramie. From several variations of experimental combinations between Panel A and Panel B, optimal combination obtained with 16 layers of panel A and 31-34 layers of panel B which is able to protect againts cal. 7.65 mm × 17 mm (.32 ACP) bullet fired through pistol .32 Pindad from a distance of 20 meters. Panel with a size of 20 cm × 20 cm has a total thickness between 12,922 to13,745 mm and a total weight between 506,26 to 520,926gram. Scanning electron microscopy (SEM) observations indicated that the porosity and surface area of the ramie fiber is smooth, fiber surfaces showed topography with micropores. SEM also showed well-arranged structure of fibers bonding. Energy Dispersive X-ray (EDX) analysis indicated 100 % carbon contents in ramie fiber. Test result indicates that panel from composite ramie-epoxide can reach the level 1of International Standard of NIJ - 010104. Compared to panel from polyester fiber, the panel from composite ramie-epoxide (0,50-0,52 kg) is lighter weight than panel polyester fiber (1,642 kg)

  9. Combination of natural fiber Boehmeria nivea (ramie) with matrix epoxide for bullet proof vest body armor

    International Nuclear Information System (INIS)

    Anggoro, Didi Dwi; Kristiana, Nunung

    2015-01-01

    Ballistic protection equipment, such as a bulletproof vest, is a soldier’s most important means of preserving life and survivability in extreme combat conditions. The bulletproof vests are designed to protect the user’s chest from injury without disturbing the ability to perform his duties. Aromatic polyamide or aramid fibers known under the trade name Kevlar, Trawon and so is synthetic fiber materials commonly used in the manufacture of bulletproof vests. This synthetic fibers have high tensile strength and ductility. Kevlar is expensive and imported material. In this study, will introduce local natural raw materials, ramie fiber (Boehmeria nivea) which is cheaper and environmentally friendly. It has enough tenacity and tensile strength as a bulletproof vest. This experiment uses two panels, there are Panel A as front surface of Panel B. Panel A is a combination of ramie and epoxide matrix, while panel B is only ramie. From several variations of experimental combinations between Panel A and Panel B, optimal combination obtained with 16 layers of panel A and 31-34 layers of panel B which is able to protect againts cal. 7.65 mm × 17 mm (.32 ACP) bullet fired through pistol .32 Pindad from a distance of 20 meters. Panel with a size of 20 cm × 20 cm has a total thickness between 12,922 to13,745 mm and a total weight between 506,26 to 520,926gram. Scanning electron microscopy (SEM) observations indicated that the porosity and surface area of the ramie fiber is smooth, fiber surfaces showed topography with micropores. SEM also showed well-arranged structure of fibers bonding. Energy Dispersive X-ray (EDX) analysis indicated 100 % carbon contents in ramie fiber. Test result indicates that panel from composite ramie-epoxide can reach the level 1of International Standard of NIJ - 010104. Compared to panel from polyester fiber, the panel from composite ramie-epoxide (0,50-0,52 kg) is lighter weight than panel polyester fiber (1,642 kg)

  10. Linking embryo toxicity with genotoxic responses in the freshwater snail Physa acuta: single exposure to benzo(a)pyrene, fluoxetine, bisphenol A, vinclozolin and exposure to binary mixtures with benzo(a)pyrene.

    Science.gov (United States)

    Sánchez-Argüello, Paloma; Aparicio, Natalia; Fernández, Carlos

    2012-06-01

    Genotoxic effects on fauna after waterborne pollutant exposure have been demonstrated by numerous research programmes. Less effort has been focused on establishing relationship between genotoxicity and long-term responses at higher levels of biological organization. Taking into account that embryos may be more sensitive indicators of reproductive impairment than alterations in fertility, we have developed two assays in multiwell plates to address correlations between embryo toxicity and genotoxicity. The potential teratogenicity was assessed by analyzing abnormal development and mortality of Physa acuta at embryonic stage. Genotoxicity was measured by the micronucleus (MN) test using embryonic cells. Our results showed that linkage between genotoxicity and embryo toxicity depends on mechanisms of action of compounds under study. Embryo toxic responses showed a clear dose-related tendency whereas no clear dose-dependent effect was observed in micronucleus induction. The higher embryo toxicity was produced by benzo(a)pyrene exposure followed by fluoxetine and bisphenol A. Vinclozolin was the lower embryo toxic compound. Binary mixtures with BaP always resulted in higher embryo toxicity than single exposures but antagonistic effects were observed for MN induction. Benzo(a)pyrene produced the higher MN induction at 0.04 mg/L, which also produced clear embryo toxic effects. Fluoxetine did not induce cytogenetic effects but 0.25mg/L altered embryonic development. Bisphenol A significantly reduced hatchability at 0.5mg/L while MN induction appeared with higher treatments than those that start causing teratogenicity. Much higher concentration of vinclozolin (5mg/L) reduced hatchability and induced maximum MN formation. In conclusion, while validating one biomarker of genotoxicity and employing one ecologically relevant effect, we have evaluated the relative sensitivity of a freshwater mollusc for a range of chemicals. The embryo toxicity test is a starting point for the

  11. Benzo(a)pyrene accumulation in soils of technogenic emission zone by subcritical water extraction method

    Science.gov (United States)

    Sushkova, Svetlana; Minkina, Tatiana; Kizilkaya, Ridvan; Mandzhieva, Saglara; Batukaev, Abdulmalik; Bauer, Tatiana; Gulser, Coskun

    2016-04-01

    The purpose of research is the assessment of main marker of polycyclic aromatic hydrocarbons contamination, benzo[a]pyrene (BaP) content in soils of emission zone of the power complex plant in soils with use of ecologically clean and effective subcritical water extraction method. Studies were conducted on the soils of monitoring plots subjected to Novocherkassk Power Plant emissions from burning coal. In 2000, monitoring plots were established at different distances from the NPS (1.0-20.0 km). Soil samples for the determination of soil properties and the contents of BaP were taken from a depth of 0-20 cm. The soil cover in the region under study consisted of ordinary chernozems, meadow-chernozemic soils, and alluvial meadow soils. This soil revealed the following physical and chemical properties: Corg-3.1-5.0%, pH-7.3-7.6, ECE-31.2-47.6 mmol(+)/100g; CaCO3-0.2-1.0%, the content of physical clay - 51-67% and clay - 3-37%. BaP extraction from soils was carried out by a subcritical water extraction method. Subcritical water extraction of BaP from soil samples was conducted in a specially developed extraction cartridge made of stainless steel and equipped with screw-on caps at both ends. It was also equipped with a manometer that included a valve for pressure release to maintain an internal pressure of 100 atm. The extraction cartridge containing a sample and water was placed into an oven connected to a temperature regulator under temperature 250oC and pressure 60 atm. The BaP concentration in the acetonitrile extract was determined by HPLC. The efficiency of BaP extraction from soil was determined using a matrix spike. The main accumulation of pollutant in 20 cm layer of soils is noted directly in affected zone on the plots situated at 1.2, 1.6, 5.0, 8.0 km from emission source in the direction of prevailing winds. The maximum quantity of a pollutant was founded in the soil of the plot located mostly close to a source of pollution in the direction of prevailing winds

  12. Perfluoroalkylated Derivatives of Diols and Triols. Selectivity in the Reaction of Primary and Secondary Hydroxy Groups with Perfluoroalkylepoxides. Hemocompatibility and Effect on Perfluorocarbon Emulsion

    Czech Academy of Sciences Publication Activity Database

    Církva, Vladimír; Polák, R.; Paleta, O.; Kodíček, K.; Forman, S.

    2002-01-01

    Roč. 67, č. 10 (2002), s. 1436-1448 ISSN 0010-0765 R&D Projects: GA ČR GA203/98/1174; GA MŠk LB98233 Keywords : perfluoroalkyl epoxides * fluoroalkylations * fluorophilic triols Subject RIV: CC - Organic Chemistry Impact factor: 0.848, year: 2002

  13. Performance of magnetorheological elastomer based green epoxidized natural rubber/sucrose acetate isobutyrate hybrid matrix

    Science.gov (United States)

    Khairi, Muntaz Hana Ahmad; Amri Mazlan, Saiful; Aziz, Siti Aishah Abdul; Ubaidillah; Tan Shilan, Salihah

    2018-04-01

    This study introduces a sucrose acetate isobutyrate (SAIB) as a novel additive of magnetorheological elastomers (MREs). The MREs utilized an epoxidized natural rubber (ENR) as the matrix and carbonyl iron particles (CIPs) as their filler. The CIPs were fixed at 60 wt%. The viscosity of the compound was observed using a viscometer. Meanwhile, the microstructures were observed by using field emission scanning electron microscope (FESEM). Rheological properties regarding shear storage modulus were measured by using a rheometer (MCR 302, Anton Paar). The experimental results demonstrated that the MREs-based ENR/SAIB had a decrement in their viscosity by 40% reduction. Moreover, the magnetorheological (MR) effect increased by 23% as the increment of magnetic fields. The morphological photograph showed that the CIPs embedded well within the matrix. The fabricated MREs samples were strain dependent, where all MREs samples exhibit the deteriorating trend when increasing the strain amplitude.

  14. Synthesis, Characterization and Epoxidation of cis-Enriched New Polycarbonates Catalyzed by Efficient Organotin Compound

    Directory of Open Access Journals (Sweden)

    A. H. Massoudi

    2011-01-01

    Full Text Available Presence of active functional groups on polymer chain is a suitable aspect of polymer structure which allows performing next favourite reactions on polymer molecule. In this research a novel aromatic derivative of cis-but-2-endiol was synthesized as monomer. The synthesized monomer was polymerized using diphenyl carbonate and 1,4-butandiol as second and third monomer along with organotin catalyst. Polymerization reaction performed by using melt-phase transesterification process to produce a new terpolymer of polycarbonate. During the reaction the double bonds are preserved on polymer chain and epoxidized by m-chloroperbenzoic acid (MCBPA in good yield to demonstrate the reactivity and possibility of performing further reactions on double bonds of polymer.

  15. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Adam, Nurul Ilham [Faculty of Applied Sciences, Universiti Teknologi MARA, KampusTapah, 35400 Tapah Road, Tapah, Perak (Malaysia); Yahya, Muhd Zu Azhan [Faculty of Defence Sciences and Technology, Universiti Pertahanan Nasional Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur (Malaysia); Ali, Ab Malik Marwan [Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2015-08-28

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ({sup 1}HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in {sup 1}HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF{sub 3}SO{sub 3} show the highest conductivity. The complexation between EMG30 and LiCF{sub 3}SO{sub 3} were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

  16. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    International Nuclear Information System (INIS)

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

    2015-01-01

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ( 1 HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in 1 HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF 3 SO 3 show the highest conductivity. The complexation between EMG30 and LiCF 3 SO 3 were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

  17. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    Science.gov (United States)

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

    2015-08-01

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance (1HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in 1HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF3SO3 show the highest conductivity. The complexation between EMG30 and LiCF3SO3 were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR).

  18. Zirconium(IV)-Catalyzed Ring Opening of on-DNA Epoxides in Water.

    Science.gov (United States)

    Fan, Lijun; Davie, Christopher P

    2017-05-04

    DNA-encoded library technology (ELT) has spurred wide interest in the pharmaceutical industry as a powerful tool for hit and lead generation. In recent years a number of "DNA-compatible" chemical modifications have been published and used to synthesize vastly diverse screening libraries. Herein we report a newly developed, zirconium tetrakis(dodecyl sulfate) [Zr(DS) 4 ] catalyzed ring-opening of on-DNA epoxides in water with amines, including anilines. Subsequent cyclization of the resulting on-DNA β-amino alcohols leads to a variety of biologically interesting, nonaromatic heterocycles. Under these conditions, a library of 137 million on-DNA β-amino alcohols and their cyclization products was assembled. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Thermoset coatings from epoxidized sucrose soyate and blocked, bio-based dicarboxylic acids.

    Science.gov (United States)

    Kovash, Curtiss S; Pavlacky, Erin; Selvakumar, Sermadurai; Sibi, Mukund P; Webster, Dean C

    2014-08-01

    A new 100% bio-based thermosetting coating system was developed from epoxidized sucrose soyate crosslinked with blocked bio-based dicarboxylic acids. A solvent-free, green method was used to block the carboxylic acid groups and render the acids miscible with the epoxy resin. The thermal reversibility of this blocking allowed for the formulation of epoxy-acid thermoset coatings that are 100% bio-based. This was possible due to the volatility of the vinyl ethers under curing conditions. These systems have good adhesion to metal substrates and perform well under chemical and physical stress. Additionally, the hardness of the coating system is dependent on the chain length of the diacid used, making it tunable. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Soluble Epoxide Hydrolase Inhibitory Activity of Selaginellin Derivatives from Selaginella tamariscina

    Directory of Open Access Journals (Sweden)

    Jang Hoon Kim

    2015-12-01

    Full Text Available Selaginellin derivatives 1–3 isolated from Selaginella tamariscina were evaluated for their inhibition of soluble epoxide hydrolase (sEH to demonstrate their potential for the treatment of cardiovascular disease. All selaginellin derivatives (1–3 inhibited sEH enzymatic activity and PHOME hydrolysis, in a dose-dependent manner, with IC50 values of 3.1 ± 0.1, 8.2 ± 2.2, and 4.2 ± 0.2 μM, respectively. We further determined that the derivatives function as non-competitive inhibitors. Moreover, the predicted that binding sites and interaction between 1–3 and sEH were solved by docking simulations. According to quantitative analysis, 1–3 were confirmed to have high content in the roots of S. tamariscina; among them, selaginellin 3 exhibited the highest content of 189.3 ± 0.0 μg/g.

  1. Investigation on magnetic field dependent modulus of epoxidized natural rubber based magnetorheological elastomer

    International Nuclear Information System (INIS)

    Yunus, N. A.; Mazlan, S. A.; Ubaidillah; Aziz, S. A. A.; Khairi, M. H. Ahmad; Wahab, N. A. A.; Shilan, S. T.

    2016-01-01

    This paper presents an investigation on the use of epoxidized natural rubber (ENR) as a matrix of magnetorheological elastomers (MREs). Isotropic ENR-based MRE samples were synthesized by homogeneously mixed the ENR compound with carbonyl iron particles (CIPs). The microstructure of the sample was observed, and the magnetic field-dependent moduli were analyzed using rheometer. The influences of excitation frequency, CIPs content and magnetic field on the field-dependent moduli of ENR-based MREs were evaluated through dynamic shear test. The microstructure of MRE samples demonstrated the dispersed CIPs in the ENR matrix. The remarkable increment of storage and loss moduli of the ENR-based MREs has exhibited the magnetically controllable storage and loss moduli of the samples when exposed to the magnetic field. Consequently, the CIPs content, frequency and magnetic field were significantly influenced the dynamic moduli of the ENR-based MREs. (paper)

  2. Reaction of biscyclopentadienyl molybdendihalides with tert.-butyl hydroperoxide and its using for cyclohexene epoxidation

    International Nuclear Information System (INIS)

    Aleksandrov, Yu.A.; Fomin, V.M.; Kolmakov, A.O.

    1983-01-01

    As a result of reactions of biscyclopentadienyl molybden-dihalides (Cp 2 MoX 2 , X=Cl, Br or I) with tert.-butyl hydroperoxide, tert.-butylperoxides of biscyclopentadienyl molybdendichloride and-dibromide are synthesized for the first time, which are characterized by physico-chemical properties. Cyclohexene in the reaction mixture of Cp 2 MoX 2 with tert -butyl hydroperoxide is oxidated to form cyclohexene oxide, the reaction proceeding at a high rate and with a quantitative yield. Tert.-butylperoxide of biscyclopentadienyl molybdendihalide is responsible for the cyclohexene epoxidation reaction. The schemes for the mechanism of Cp 2 MoX 2 reactions with tert.-butyl hydroperoxide in the absence and presence of olefine are suggested

  3. Extremely efficient crystallization of HKUST-1 and Keggin-loaded related phases through the epoxide route.

    Science.gov (United States)

    Oestreicher, Víctor; Jobbágy, Matías

    2017-03-25

    Highly crystalline HKUST-1 and COK-16-like phases were obtained based on a mild in situ alkalinization one-pot epoxide driven method. A slurry composed of finely ground trimesic acid, H 3 BTC, dispersed in a CuCl 2 aqueous solution quantitatively developed well crystallized HKUST-1 after the addition of propylene oxide. The use of solid H 3 BTC ensures a low concentration of free linker, favoring crystalline growth over the precipitation of amorphous or metastable impurities. An extreme space-time yield of 2.1 × 10 5 kg m -3 day -1 was reached, with no linker excess and minimum use of solvent. The method was equally efficient in the achievement of pure NENU/COK-16 phases, containing [PW 12 O 40 ] 3- , [PMo 12 O 40 ] 3- and [SiMo 12 O 40 ] 4- polyoxometalates.

  4. FTIR and morphology of liquid epoxidized natural rubber acrylate (LENRA)/silica hybrid composites

    International Nuclear Information System (INIS)

    Eda Yuhana Ariffin; Azizan Ahmad; Dahlan Mohd; Mahathir Mohamed

    2009-01-01

    Synthesis of organic-inorganic hybrid composites was carried out by combination of liquid epoxidized natural rubber acrylate (LENRA) and silica. Silica was introduce to the matrix by sol gel technique. The sol-gel technique was employed to prepare silica using tetraethyorthosilicate (TEOS) as precursor. HDDA and irga cure 184 were added to the formulations as reactive diluents and photosensitizer, respectively. The chemical modification was studied by Fourier Transform Infrared (FTIR) and energy dispersive X-ray analysis (EDAX). The morphological studies were conducted by the optical and scanning electron microscopes (SEM). It shows that silica was dispersed very well in the matrix for lower concentration of TEOS while agglomeration occurs at the higher concentration. The average particles size of silica were less than 100 nm. (Author)

  5. Effects of benzo(a)pyrene exposure on the ATPase activity and calcium concentration in the hippocampus of neonatal rats.

    Science.gov (United States)

    Yang, Kai; Chen, Chengzhi; Cheng, Shuqun; Cao, Xianqing; Tu, Baijie

    2017-03-30

    To investigate whether postnatal benzo(a)pyrene (B(a)P) exposure caused the impairments on the process of neurodevelopment and the alteration in the calcium medium in the neonatal rats. Eighty neonatal Sprague Dawley (SD) rats were randomly divided into 5 groups (untreated control group, vehicle group, 0.02 mg/kg, 0.2 mg/kg and 2 mg/kg B(a)P-exposed group). Rats were treated with B(a)P by the intragastric administration from postnatal day (PND) 4 to 25. Morris water maze (MWM) was employed to observe the spatial memory of rats. The activity of calcium adenosine triphosphatase (Ca2+-ATPase), sodium-potassium adenosine triphosphatase (Na+-K+-ATPase) and calcium-magnesium adenosine triphosphatase (Ca2+-Mg2+-ATPase) in the hippocampus were detected by commercial kits. Fura-2 pentakis(acetoxymethyl) (Fura-2/AM) probe and reactive oxygen species (ROS) reagent kit were used for measuring the concentration of Ca2+ and ROS in the hippocampus synapse, respectively. Rats exposed to B(a)P resulted in the deficits in the spatial memory manifested by the increased escape latency and decreased number of crossing platform and time spent in target quadrant in comparison with the control groups. Benzo(a)pyrene exposure caused the significant decrease in the ATPase activity in the hippocampus and caused Ca2+ overload in the synaptic, besides, the ROS concentration increased significantly which may further induce neurobehavioral impairment of the neonatal rats. Our findings suggest that postnatal B(a)P exposure may cause the neurobehavioral impairments in the neonatal rats, which were mediated by the decreased ATPase activity and elevated Ca2+ concentration. Int J Occup Med Environ Health 2017;30(2):203-211. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  6. Cytochrome b5 and epoxide hydrolase contribute to benzo[a]pyrene-DNA adduct formation catalyzed by cytochrome P450 1A1 under low NADPH:P450 oxidoreductase conditions

    International Nuclear Information System (INIS)

    Stiborová, Marie; Moserová, Michaela; Černá, Věra; Indra, Radek; Dračínský, Martin; Šulc, Miroslav; Henderson, Colin J.; Wolf, C. Roland; Schmeiser, Heinz H.; Phillips, David H.; Frei, Eva; Arlt, Volker M.

    2014-01-01

    In previous studies we had administered benzo[a]pyrene (BaP) to genetically engineered mice (HRN) which do not express NADPH:cytochrome P450 oxidoreductase (POR) in hepatocytes and observed higher DNA adduct levels in livers of these mice than in wild-type mice. To elucidate the reason for this unexpected finding we have used two different settings for in vitro incubations; hepatic microsomes from control and BaP-pretreated HRN mice and reconstituted systems with cytochrome P450 1A1 (CYP1A1), POR, cytochrome b 5 , and epoxide hydrolase (mEH) in different ratios. In microsomes from BaP-pretreated mice, in which Cyp1a1 was induced, higher levels of BaP metabolites were formed, mainly of BaP-7,8-dihydrodiol. At a low POR:CYP1A1 ratio of 0.05:1 in the reconstituted system, the amounts of BaP diones and BaP-9-ol formed were essentially the same as at an equimolar ratio, but formation of BaP-3-ol was ∼1.6-fold higher. Only after addition of mEH were BaP dihydrodiols found. Two BaP-DNA adducts were formed in the presence of mEH, but only one when CYP1A1 and POR were present alone. At a ratio of POR:CYP1A1 of 0.05:1, addition of cytochrome b 5 increased CYP1A1-mediated BaP oxidation to most of its metabolites indicating that cytochrome b 5 participates in the electron transfer from NADPH to CYP1A1 required for enzyme activity of this CYP. BaP-9-ol was formed even by CYP1A1 reconstituted with cytochrome b 5 without POR. Our results suggest that in livers of HRN mice Cyp1a1, cytochrome b 5 and mEH can effectively activate BaP to DNA binding species, even in the presence of very low amounts of POR

  7. Epoxide hydrolase-catalyzed enantioselective conversion of trans-stilbene oxide: Insights into the reaction mechanism from steady-state and pre-steady-state enzyme kinetics

    Czech Academy of Sciences Publication Activity Database

    Archelas, A.; Zhao, W.; Faure, B.; Iacazio, G.; Kotík, Michael

    2016-01-01

    Roč. 591, FEB 2016 (2016), s. 66-75 ISSN 0003-9861 Institutional support: RVO:61388971 Keywords : Catalytic mechanism * Epoxide hydrolase * Electrophilic catalysis Subject RIV: CE - Biochemistry Impact factor: 3.165, year: 2016

  8. Heterogeneous catalytic epoxidation of C/sub 8/-C/sub 1/4 olefins by tert. -butyl hydroperoxide

    Energy Technology Data Exchange (ETDEWEB)

    Dahlmann, J; Hoeft, E; Boeden, H F; Dilcher, H

    1979-09-01

    Heterogeneous catalytic epoxidation of C/sub 8/-C/sub 14/ olefins by tert.-butyl hydroperoxide (TBHP) avoids large product losses to side reactions, associated with the use of homogeneous catalysts, such as Mo(CO)/sub 6/. With an unsupported MoO/sub 3/ catalyst, 48% TBHP conversion was achieved after one hour (vs. 24% after two hours for Mo(CO)/sub 6/) in 1-octene epoxidation at 90/sup 0/C and 2:1:3 octene/TBHP/toluene (solvent) molar ratio. The use of silica-supported catalysts, such as Bi/sub 9/PMo/sub 12/O/sub 52//30% SiO/sub 2/ (ACN, an industrial catalyst for acrylonitrile), MoO/sub 3//30% SiO/sub 2/ (D-1), 3MoO/sub 3/-Sb/sub 2/O/sub 5//50% SiO/sub 2/ (D-2), or 2MoO/sub 3/-As/sub 2/O/sub 3//50% SiO/sub 2/ (D-3) increased the conversion to 68, 67, 70, and 73%, respectively, with up to 95-99% selectivities for the epoxide. Under optimum conditions of 3:1 olefin/TBHP, 110/sup 0/C, and 2-4 g/l. catalyst, TBHP conversions in epoxidation of 1-tetradecene in a batch reactor over ACN, D-2, and D-3 after two hours were 94, 88, and 91%, respectively, but they decreased to 52, 78, and 79%, respectively, after five two-hour operating cycles. In epoxidation of 1-decene or a mixture of decene isomers (a model for the industrial olefin mixtures obtained by paraffin dehydrogenation via the Parex process) carried out in a continuous flow reactor over the D-3 catalyst at 90/sup 0/-110/sup 0/C, stable catalytic activities with TBHP conversions of approx. 90% and 90-96% selectivities for epoxides were observed for about 900 hr.

  9. Role of keto–enol tautomerization in a chiral phosphoric acid catalyzed asymmetric thiocarboxylysis of meso-epoxide: a DFT study

    KAUST Repository

    Ajitha, Manjaly John; Huang, Kuo-Wei

    2015-01-01

    The mechanism of a chiral phosphoric acid catalyzed thiocarboxylysis of meso-epoxide was investigated by density functional theory (DFT) calculations (M06-2X). The nucleophilic ring opening of epoxide by thiobenzoic acid was found to proceed via a concerted termolecular transition state with a simultaneous dual proton transfer to yield the β-hydroxy thioester product. Electrostatic interactions together with the steric environment inside the chiral catalyst play an important role in determining the enantioselectivity of the reaction.

  10. Role of keto–enol tautomerization in a chiral phosphoric acid catalyzed asymmetric thiocarboxylysis of meso-epoxide: a DFT study

    KAUST Repository

    Ajitha, Manjaly John

    2015-09-15

    The mechanism of a chiral phosphoric acid catalyzed thiocarboxylysis of meso-epoxide was investigated by density functional theory (DFT) calculations (M06-2X). The nucleophilic ring opening of epoxide by thiobenzoic acid was found to proceed via a concerted termolecular transition state with a simultaneous dual proton transfer to yield the β-hydroxy thioester product. Electrostatic interactions together with the steric environment inside the chiral catalyst play an important role in determining the enantioselectivity of the reaction.

  11. Catalytic Efficiency of Titanium Dioxide (TiO2) and Zeolite ZSM-5 Catalysts in the in-situ Epoxidation of Palm Olein

    Science.gov (United States)

    Yunus, M. Z. Mohd; Jamaludin, S. K.; Abd. Karim, S. F.; Gani, A. Abd; Sauki, A.

    2018-05-01

    Titanium dioxide and zeolite ZSM-5 are the commonly used heterogeneous catalysts in many chemical reactions. They have several advantages such as low cost and environmental friendly. In this study, titanium dioxide and zeolite ZSM-5 act as catalyst in the in-situ epoxidation of palm olein. Epoxidation of palm olein was carried out by using in-situ generated performic acid to produce epoxidized palm olein in a semi-batch reactor at different temperatures (45°C and 60°C) and agitation speed of 400 rpm. The effects of both catalysts are studied to compare their efficiency in catalyzing the in-situ epoxidation. Epoxidized palm olein was analyzed by using percent of relative conversion to oxirane (RCO%) and fourier transform infrared spectroscopy (FTIR). Surface area of the catalysts used were then characterized by using BET. The results indicated that titanium dioxide is a better catalyst in the in-situ epoxidation of palm olein since it provides higher RCO% compared to Zeolite ZSM-5 at 45°C.

  12. Analytical approaches for the detection of epoxides and hydroperoxides in active pharmaceutical ingredients, drug products and herbals.

    Science.gov (United States)

    Elder, D P; Snodin, D; Teasdale, A

    2010-04-06

    This review summarizes the analytical approaches reported in the literature relating to epoxide and hydroperoxide impurities. It is intended that it should provide guidance for analysts faced by the need to control such impurities, particularly where this is due to concerns relating to their potential genotoxicity. An extensive search of the literature relating to this class of impurities revealed a large number of references relating to analysis of epoxides/hydroperoxides associated with herbal remedies. Given the general applicability of the analytical methodology and due to the widespread use of herbal products the authors decided to include herbal medicines in this review. The review also reflects on the very different approaches taken in terms of the assessment/control of genotoxic impurities for such herbal remedies to that required for pharmaceutical products. Copyright 2009 Elsevier B.V. All rights reserved.

  13. Iron-functionalized nanoporous silica type SBA-15: Synthesis, characterization and application in alkene epoxidation in presence of hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Mahdieh Ghazizadeh

    2017-05-01

    Full Text Available Fe(IIIsalophen complex on a SBA-15 support functionalized with (3-aminopropyltriethoxysilane as a linker. It has been synthesized and characterized by XRD, adsorption–desorption of nitrogen, SEM, FT-IR and UV–Vis. The formation of metal-salophen complex with the amino groups as connectors to the SBA-15 surface was confirmed. This material was successfully used as a heterogeneous catalyst for the epoxidation of alkenes and the effects of reaction time, different solvents and amount of catalyst on catalytic activity were investigated. This catalyst gave suitable and comparable yield and percentage conversion values. It is also stable and can be recycled and reused in the epoxidation of alkenes.

  14. Immersion calorimetry as a tool to evaluate the catalytic performance of titanosilicate materials in the epoxidation of cyclohexene.

    Science.gov (United States)

    Vernimmen, Jarian; Guidotti, Matteo; Silvestre-Albero, Joaquin; Jardim, Erika O; Mertens, Myrjam; Lebedev, Oleg I; Van Tendeloo, Gustaaf; Psaro, Rinaldo; Rodríguez-Reinoso, Francisco; Meynen, Vera; Cool, Pegie

    2011-04-05

    Different types of titanosilicates are synthesized, structurally characterized, and subsequently catalytically tested in the liquid-phase epoxidation of cyclohexene. The performance of three types of combined zeolitic/mesoporous materials is compared with that of widely studied Ti-grafted-MCM-41 molecular sieve and the TS-1 microporous titanosilicate. The catalytic test results are correlated with the structural characteristics of the different catalysts. Moreover, for the first time, immersion calorimetry with the same substrate molecule as in the catalytic test reaction is applied as an extra means to interpret the catalytic results. A good correlation between catalytic performance and immersion calorimetry results is found. This work points out that the combination of catalytic testing and immersion calorimetry can lead to important insights into the influence of the materials structural characteristics on catalysis. Moreover, the potential of using immersion calorimetry as a screening tool for catalysts in epoxidation reactions is shown.

  15. 2-Butyne-1,4-diol as a novel corrosion inhibitor for API X65 steel pipeline in carbonate/bicarbonate solution

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi Meresht, E. [Materials Engineering Department, Faculty of Engineering, Tarbiat Modares University, 1411713114, Tehran (Iran, Islamic Republic of); Shahrabi Farahani, T., E-mail: tshahrabi34@modares.ac.ir [Materials Engineering Department, Faculty of Engineering, Tarbiat Modares University, 1411713114, Tehran (Iran, Islamic Republic of); Neshati, J. [Research Institute of Petroleum Industry, RIPI, 1485733111, Tehran (Iran, Islamic Republic of)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Corrosion of API 5L X65 is effectively reduced by the addition of the inhibitor. Black-Right-Pointing-Pointer The techniques include weight loss, potentiodynamic polarization, EIS and AFM. Black-Right-Pointing-Pointer 2-Butyne-1,4-diol acts as a mixed-type inhibitor. Black-Right-Pointing-Pointer The adsorption of 2-butyne-1,4-diol obeys Langmuir adsorption isotherm. - Abstract: The inhibition effects of 2-butyne-1,4-diol on the corrosion susceptibility of grade API 5L X65 steel pipeline in 2 M Na{sub 2}CO{sub 3}/1 M NaHCO{sub 3} solution were studied by electrochemical techniques and weight loss measurements. The results indicated that this inhibitor was a mixed-type inhibitor, with a maximum percentage inhibition efficiency of approximately 92% in the presence of 5 mM inhibitor. Atomic force microscopy revealed that a protective film was formed on the surface of the inhibited sample. The adsorption of the inhibitor was found to conform to the Langmuir isotherm with the standard adsorption free energy of -21.08 kJ mol{sup -1}.

  16. 2-Butyne-1,4-diol as a novel corrosion inhibitor for API X65 steel pipeline in carbonate/bicarbonate solution

    International Nuclear Information System (INIS)

    Sadeghi Meresht, E.; Shahrabi Farahani, T.; Neshati, J.

    2012-01-01

    Highlights: ► Corrosion of API 5L X65 is effectively reduced by the addition of the inhibitor. ► The techniques include weight loss, potentiodynamic polarization, EIS and AFM. ► 2-Butyne-1,4-diol acts as a mixed-type inhibitor. ► The adsorption of 2-butyne-1,4-diol obeys Langmuir adsorption isotherm. - Abstract: The inhibition effects of 2-butyne-1,4-diol on the corrosion susceptibility of grade API 5L X65 steel pipeline in 2 M Na 2 CO 3 /1 M NaHCO 3 solution were studied by electrochemical techniques and weight loss measurements. The results indicated that this inhibitor was a mixed-type inhibitor, with a maximum percentage inhibition efficiency of approximately 92% in the presence of 5 mM inhibitor. Atomic force microscopy revealed that a protective film was formed on the surface of the inhibited sample. The adsorption of the inhibitor was found to conform to the Langmuir isotherm with the standard adsorption free energy of −21.08 kJ mol −1 .

  17. Isolation of endosulfan sulfate-degrading Rhodococcus koreensis strain S1-1 from endosulfan contaminated soil and identification of a novel metabolite, endosulfan diol monosulfate

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Koji; Kawashima, Fujimasa [Department of Applied Biology and Chemistry, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502 (Japan); Organochemicals Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604 (Japan); Takagi, Kazuhiro, E-mail: ktakagi@affrc.go.jp [Department of Applied Biology and Chemistry, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502 (Japan); Organochemicals Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604 (Japan); Kataoka, Ryota [Department of Environmental Science, University of Yamanashi, 41-4-37 Takeda, Kofu, Yamanashi (Japan); Kotake, Masaaki [Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 981-8555 (Japan); Kiyota, Hiromasa [Graduate School of Environmental & Life Science, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 (Japan); Yamazaki, Kenichi [Organochemicals Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604 (Japan); Sakakibara, Futa [Organochemicals Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604 (Japan); The Japan Society for the Promotion of Science(JSPS), 1-8 Chiyoda-ku, Tokyo (Japan); Okada, Sanae [Department of Applied Biology and Chemistry, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502 (Japan)

    2016-05-13

    An aerobic endosulfan sulfate-degrading bacterium, Rhodococcus koreensis strain S1-1, was isolated from soil to which endosulfan had been applied annually for more than 10 years until 2008. The strain isolated in this work reduced the concentration of endosulfan sulfate (2) from 12.25 μM to 2.11 μM during 14 d at 30 °C. Using ultra performance liquid chromatography-electrospray ionization-mass spectroscopy (UPLC-ESI-MS), a new highly water-soluble metabolite possessing six chlorine atoms was found to be endosulfan diol monosulfate (6), derived from 2 by hydrolysis of the cyclic sulfate ester ring. The structure of 6 was elucidated by chemical synthesis of the candidate derivatives and by HR-MS and UPLC-MS analyses. Therefore, it was suggested that the strain S1-1 has a new metabolic pathway of 2. In addition, 6 was expected to be less toxic among the metabolites of 1 because of its higher water-solubility. -- Highlights: •A novel endosulfan sulfate-degrading bacterium was isolated and named strain S1-1. •Strain S1-1 degraded endosulfan sulfate into a novel metabolite endosulfan diol monosulfate. •Endosulfan diol monosulfate showed higher polarity than other known metabolites of endosulfan. •We proposed the plausible metabolic pathway of endosulfan in terms of organic chemistry.

  18. Isolation of endosulfan sulfate-degrading Rhodococcus koreensis strain S1-1 from endosulfan contaminated soil and identification of a novel metabolite, endosulfan diol monosulfate

    International Nuclear Information System (INIS)

    Ito, Koji; Kawashima, Fujimasa; Takagi, Kazuhiro; Kataoka, Ryota; Kotake, Masaaki; Kiyota, Hiromasa; Yamazaki, Kenichi; Sakakibara, Futa; Okada, Sanae

    2016-01-01

    An aerobic endosulfan sulfate-degrading bacterium, Rhodococcus koreensis strain S1-1, was isolated from soil to which endosulfan had been applied annually for more than 10 years until 2008. The strain isolated in this work reduced the concentration of endosulfan sulfate (2) from 12.25 μM to 2.11 μM during 14 d at 30 °C. Using ultra performance liquid chromatography-electrospray ionization-mass spectroscopy (UPLC-ESI-MS), a new highly water-soluble metabolite possessing six chlorine atoms was found to be endosulfan diol monosulfate (6), derived from 2 by hydrolysis of the cyclic sulfate ester ring. The structure of 6 was elucidated by chemical synthesis of the candidate derivatives and by HR-MS and UPLC-MS analyses. Therefore, it was suggested that the strain S1-1 has a new metabolic pathway of 2. In addition, 6 was expected to be less toxic among the metabolites of 1 because of its higher water-solubility. -- Highlights: •A novel endosulfan sulfate-degrading bacterium was isolated and named strain S1-1. •Strain S1-1 degraded endosulfan sulfate into a novel metabolite endosulfan diol monosulfate. •Endosulfan diol monosulfate showed higher polarity than other known metabolites of endosulfan. •We proposed the plausible metabolic pathway of endosulfan in terms of organic chemistry.

  19. Microsomal epoxide hydrolase gene polymorphisms and risk of chronic obstructive pulmonary disease: A comprehensive meta-analysis

    OpenAIRE

    LI, HUI; FU, WEI-PING; HONG, ZE-HUI

    2012-01-01

    Microsomal epoxide hydrolase (EPHX1) is an enzyme involved in the detoxification the products of smoking and is proposed to be a genetic factor for the development of chronic obstructive pulmonary disease (COPD). Two functional polymorphisms of EPHX1, T113C and A139G, have been analyzed in numerous studies to assess the COPD risk attributed to these variants. However, the conclusions were controversial. We performed a comprehensive meta-analysis to clarify these findings. A total of 24 studie...

  20. Enantioselective syntheses of aeruginosin 298-A and its analogues using a catalytic asymmetric phase-transfer reaction and epoxidation.

    Science.gov (United States)

    Ohshima, Takashi; Gnanadesikan, Vijay; Shibuguchi, Tomoyuki; Fukuta, Yuhei; Nemoto, Tetsuhiro; Shibasaki, Masakatsu

    2003-09-17

    We developed a versatile synthetic process for aeruginosin 298-A as well as several attractive analogues, in which all stereocenters were controlled by a catalytic asymmetric phase-transfer reaction and epoxidation. Furthermore, drastic counteranion effects in phase-transfer catalysis were observed for the first time, making it possible to three-dimensionally fine-tune the catalyst (ketal part, aromatic part, and counteranion).

  1. Silica-supported, single-site titanium catalysts for olefin epoxidation. A molecular precursor strategy for control of catalyst structure.

    Science.gov (United States)

    Jarupatrakorn, Jonggol; Don Tilley, T

    2002-07-17

    A molecular precursor approach involving simple grafting procedures was used to produce site-isolated titanium-supported epoxidation catalysts of high activity and selectivity. The tris(tert-butoxy)siloxy titanium complexes Ti[OSi(O(t)Bu)(3)](4) (TiSi4), ((i)PrO)Ti[OSi(O(t)Bu)(3)](3) (TiSi3), and ((t)BuO)(3)TiOSi(O(t)Bu)(3) (TiSi) react with the hydroxyl groups of amorphous Aerosil, mesoporous MCM-41, and SBA-15 via loss of HO(t)Bu and/or HOSi(O(t)Bu)(3) and introduction of titanium species onto the silica surface. Powder X-ray diffraction, nitrogen adsorption/desorption, infrared, and diffuse reflectance ultraviolet spectroscopies were used to investigate the structures and chemical natures of the surface-bound titanium species. The titanium species exist mainly in isolated, tetrahedral coordination environments. Increasing the number of siloxide ligands in the molecular precursor decreases the amount of titanium that can be introduced this way, but also enhances the catalytic activity and selectivity for the epoxidation of cyclohexene with cumene hydroperoxide as oxidant. In addition, the high surface area mesoporous silicas (MCM-41 and SBA-15) are more effective than amorphous silica as supports for these catalysts. Supporting TiSi3 on the SBA-15 affords highly active cyclohexene epoxidation catalysts (0.25-1.77 wt % Ti loading) that provide turnover frequencies (TOFs) of 500-1500 h(-1) after 1 h (TOFs are reduced by about half after calcination). These results demonstrate that oxygen-rich siloxide complexes of titanium are useful as precursors to supported epoxidation catalysts.

  2. Dose-response relationship of rat aryl hydrocarbon hydroxylase and epoxide hydratase induction

    Energy Technology Data Exchange (ETDEWEB)

    Gielen, J.E.; Goujon, F.M.; Sele-Doyen, J.; Van Cantfort, J.

    1980-01-01

    This paper summarizes our recent results supporting the hypothesis that different regulation mechanisms are involved in the control of AHH and EH activity and that the AHH induction in the extrahepatic tissues might also be affected by liver specific inducers. In the rat, lung and kidney AHH is highly sensitive to the inducers present in cigarette smoke and cigarette smoke condensate, the EH activity not being affected by the same agents. Phenobarbital is also able to protentiate the inducing action of low doses of benzo(a)pyrene on the lung AHH activity. In primary rat liver cells in culture, AHH and EH can be selectivly induced. Low doses of benz(a)anthracene preferentially enhance the AHH activity while trans-stilbene oxide an various antioxidants modify only the EH activity. Phenobarbital, which also induces the AHH activity in cell culture, produces a more than additive effect when added to the culture medium in a mixture with benz(a)anthracene. Trans-stilbene oxide prevents the AHH induction by phenobarbital and not by benz(a)anthracene. Our results suggest that, in addition to its own induction capacity, phenobarbital is also able to potentiate the action of chemicals belonging to a different class of inducers.

  3. Metal–organic framework-based catalysts: Chemical fixation of CO2 with epoxides leading to cyclic organic carbonates

    Directory of Open Access Journals (Sweden)

    M. Hassan eBeyzavi

    2015-01-01

    Full Text Available As a C1 feedstock, CO2 has the potential to be uniquely highly economical in both a chemical and a financial sense. In particular, the highly atom-economical acid-catalyzed cycloaddition of CO2 to epoxides to yield cyclic organic carbonates (OCs, a functionality having many important industrial applications, is an attractive reaction for the utilization of CO2 as a chemical feedstock. Metal–organic frameworks (MOFs are promising candidates in catalysis as they are a class of crystalline, porous and functional materials with remarkable properties including great surface area, high stability, open channels and permanent porosity. MOFs structure tunability and their affinity for CO2, makes them great catalysts for the formation of OCs using CO2 and epoxides. In this review, we examine MOF-based catalytic materials for the cycloaddition of carbon dioxide to epoxides. Catalysts are grouped based on the location of catalytic sites, i.e., at the struts, nodes, defect sites, or some combination thereof. Additionally, important features of each catalyst system are critically discussed.

  4. Metal-Free Alternating Copolymerization of CO2with Epoxides: Fulfilling “Green” Synthesis and Activity

    KAUST Repository

    Zhang, Dongyue

    2016-08-16

    Polycarbonates were successfully synthesized for the first time through the anionic copolymerization of epoxides with CO2, under metal-free conditions. Using an approach based on the activation of epoxides by Lewis acids and of CO, by appropriate cations, well-defined alternating copolymers made of CO, and propylene oxide (PO) or cyclohexene oxide (CHO) were indeed obtained. Triethyl borane was the Lewis acid chosen to activate the epoxides, and onium halides or onium alkoxides involving either ammonium, phosphonium, or phosphazenium cations were selected to initiate the copolymerization. In the case of PO, the carbonate content of the poly(propylene carbonate) formed was in the range of 92-99% and turnover numbers (TON) were close to 500; in the case of CHO perfectly alternating poly(cyclohexene carbonate) were obtained and TON values were close to 4000. The advantages of such a copolymerization system are manifold: (i) no need for multistep catalyst/ligand synthesis as in previous works; (ii) no transition metal involved in the copolymer synthesis and therefore no coloration of the samples isolated; and (iii) no necessity for postsynthesis purification.

  5. Synthesis and characterization of supported heteropolymolybdate nanoparticles between silicate layers of Bentonite with enhanced catalytic activity for epoxidation of alkenes

    International Nuclear Information System (INIS)

    Salavati, Hossein; Rasouli, Nahid

    2011-01-01

    Highlights: → The PVMo and nanocomposite catalyst (PVMo/Bentonite) as catalyst for epoxidation of alkenes. → The composite catalyst showed higher catalytic activity than parent heteropolymolybdate (PVMo). →The use of ultrasonic irradiation increased the conversions and reduced the reaction times. → The H 2 O 2 is a green and eco-friendly oxidant in this catalytic system. -- Abstract: A new heterogeneous catalyst (PVMo/Bentonite) consisting of vanadium substituted heteropolymolybdate with Keggin-type structure Na 5 [PV 2 Mo 10 O 40 ].14H 2 O (PVMo) supported between silicate layers of bentonite has been synthesized by impregnation method and characterized using X-ray diffraction, Fourier-transformed infrared spectroscopy, scanning electron microscopy, UV-vis diffuse reflectance spectroscopy, transmission electron microscopy and elemental analysis. X-ray diffraction and scanning electron microscopy analysis indicated that PVMo was finely dispersed into layers of bentonite as support. The PVMo/Bentonite used as an efficient heterogeneous catalyst for epoxidation of alkenes. Various cyclic and linear alkenes were oxidized into the corresponding epoxides in high yields and selectivity with 30% aqueous H 2 O 2 . The catalyst was reused several times, without observable loss of activity and selectivity. The obtained results showed that the catalytic activity of the PVMo/Bentonite was higher than that of pure heteropolyanion (PVMo).

  6. Lipase catalyzed epoxidation of fatty acid methyl esters derived from unsaturated vegetable oils in absence of carboxylic acid.

    Science.gov (United States)

    Sustaita-Rodríguez, Alejandro; Ramos-Sánchez, Víctor H; Camacho-Dávila, Alejandro A; Zaragoza-Galán, Gerardo; Espinoza-Hicks, José C; Chávez-Flores, David

    2018-04-11

    Nowadays the industrial chemistry reactions rely on green technologies. Enzymes as lipases are increasing its use in diverse chemical processes. Epoxidized fatty acid methyl esters obtained from transesterification of vegetable oils have recently found applications as polymer plasticizer, agrochemical, cosmetics, pharmaceuticals and food additives. In this research article, grapeseed, avocado and olive oils naturally containing high percents of mono and poly unsaturations were used as starting materials for the production of unsaturated fatty acid methyl esters. The effect of lauric acid as an active oxygen carrier was studied on epoxidation reactions where unsaturated fatty acid methyl esters were converted to epoxy fatty acid methyl esters using immobilized Candida antarctica Lipase type B as catalyst and hydrogen peroxide as oxygen donor at mild temperature and pressure conditions. After this study it was confirmed by 1 H NMR, 13 C NMR and GC-MS that the addition of lauric acid to the enzymatic reaction is unnecessary to transform the alkenes in to epoxides. It was found that quantitative conversions were possible in despite of a carboxylic acid absence.

  7. Heteropolytungstate nanoparticles: Microemulsion-mediated preparation and investigation of their catalytic activity in the epoxidation of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Masteri-Farahani, M., E-mail: mfarahany@yahoo.com; Ghorbani, M.

    2016-04-15

    Highlights: • Keggin type Q{sub 3}PW{sub 12}O{sub 40} nanoparticles were synthesized by using microemulsion system. • The nanoparticles have uniform size of about 25 nm and spherical morphologies. • The prepared nanoparticles act as reusable catalyst in the epoxidation of olefins with H{sub 2}O{sub 2}. - Abstract: Keggin type Q{sub 3}PW{sub 12}O{sub 40} nanoparticles (Q = cetyltrimethylammonium cation) were synthesized in water-in-oil (w/o) microemulsion consisted of water/cetyltrimethylammonium bromide/n-butanol/isooctane. Reaction of Na{sub 2}WO{sub 4}, Na{sub 2}HPO{sub 4} and hydrochloric acid within water containing nanoreactors of reverse micelles resulted in the preparation of Q{sub 3}PW{sub 12}O{sub 40} nanoparticles. The resultant nanoparticles were analyzed by physicochemical methods such as FT-IR spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, thermogravimetric analyses (TGA-DTA), scanning and transmission electron microscopy and atomic force microscopy which show nearly uniform spherical nanoparticles with size of about 15 nm. Finally, catalytic activity of the Q{sub 3}PW{sub 12}O{sub 40} nanoparticles was examined in the epoxidation of olefins with H{sub 2}O{sub 2}. The prepared nanoparticles acted as recoverable and reusable catalyst in the epoxidation of olefins with H{sub 2}O{sub 2}.

  8. Natural Optical Activity of Chiral Epoxides: the Influence of Structure and Environment on the Intrinsic Chiroptical Response

    Science.gov (United States)

    Lemler, Paul M.; Craft, Clayton L.; Vaccaro, Patrick

    2017-06-01

    Chiral epoxides built upon nominally rigid frameworks that incorporate aryl substituents have been shown to provide versatile backbones for asymmetric syntheses designed to generate novel pharmaceutical and catalytic agents. The ubiquity of these species has motivated the present studies of their intrinsic (solvent-free) circular birefringence (CB), the measurement of which serves as a benchmark for quantum-chemical predictions of non-resonant chiroptical behavior and as a beachhead for understanding the often-pronounced mediation of such properties by environmental perturbations (e.g., solvation). The optical rotatory dispersion (or wavelength-resolved CB) of (R)-styrene oxide (R-SO) and (S,S)-phenylpropylene oxide (S-PPO) have been interrogated under ambient solvated and isolated conditions, where the latter efforts exploited the ultrasensitive techniques of cavity ring-down polarimetry. Both of the targeted systems display marked solvation effects as evinced by changes the magnitude and (in the case of R-SO) the sign of the extracted specific optical rotation, with the anomalously large response evoked from S-PPO distinguishing it from other members of the epoxide family. Linear-response calculations of dispersive optical activity have been performed at both density-functional and coupled-cluster levels of theory to unravel the structural and electronic origins of experimental findings, thereby suggesting the possible involvement of hindered torsional motion along dihedral coordinates adjoining phenyl and epoxide moieties.

  9. Effect of irradiation on poly(vinyl chloride)/epoxidized natural rubber blend in the presence of additives: FTIR analysis

    International Nuclear Information System (INIS)

    Chantara Thevy Ratnam; Khairul Zaman Dahlan; Baharin, A.; Nasir, M.

    2001-01-01

    The effect of irradiation on the structure of 50/50 poly(vinyl chloride)/epoxidized natural rubber blend (PVC/ENR) was studied using the Fourier Transform Spectroscopy (FTIR). The 50/50 PVC/ENR blend was irradiated by using 3.0 MeV electron beam machine at 0 and 200 kGy irradiation doses. The influence of several additives such as TMPTA, Irganox 1010, and tribasic lead sulfate on the irradiation induced changes of the blend was investigated. It was found that upon irradiation, ring opening of the epoxide groups, oxidation as well crosslinking at residual double bonds occurred, leading to decreases in the intensities of the epoxide and cis double bond bands and an increases in ether and furan bands. The addition of Irganox 1010 and tribasic lead sulfate were found to inhibit the irradiation-induced reaction in the blend to a considerable extent. The importance of TMPTA in preventing the intramolecular ring opening side chain reaction was also discussed. However, studies did not reveal the exact nature of the irradiation-induced reactions involved in the blend. (Author)

  10. Infrared, Raman and density functional characterization and structural study of 2-Nitro-2-phenyl-propane-1,3-diol

    Science.gov (United States)

    Kaya, Mehmet Fatih; Bağlayan, Özge; Kaya, Esma Güneş; Alver, Özgür

    2017-12-01

    Nitro compound and nitro derivatives are industrially important to produce rubber and agricultural chemicals. In this study, one of the promising derivatives of nitro compound 2-Nitro-2-phenyl-propane-1,3-diol (2NPP) is examined in detail. FT-Infrared and dispersive Raman spectra of 2NPP (C9H11NO4) were respectively recorded in 4000-10 cm-1 and 4000-100 cm-1. The bond distances and angles, conformational distributions, vibrational frequencies and the assignment of each mode, some thermodynamic parameters and reactivity descriptors: total energy, hardness, chemical potential, electrophilicity index, electronegativity, frontier orbitals energy gap of 2NPP were investigated by using DFT/B3LYP method with 6-31++G (d,p) basis set. In order to locate the global minimum on the potential energy surface of 2NPP, a beforehand conformational examinations were carried out using Spartan 10 along with semi-emprical PM6 method. The results of conformational analyses showed that there are five possible conformations having energies under 2 kcal/mol. Comparison of the theoretical and experimental results clearly indicates that density functional hybrid B3LYP/6-31++G (d,p) level of theory can be used to predict vibrational frequencies and structural parameters of 2NPP. Further, C1 geometry is considered to be the global minimum conformation of 2NPP.

  11. Efficiency of 1,9- Nonane-diol-diacrylate as a radiation vulcanization accelerator for natural rubber latex

    International Nuclear Information System (INIS)

    Haque, M.E.

    2003-09-01

    The efficiency of 1,9- Nonane-diol-diacrylate (NDDA) as a radiation vulcanization accelerator (RVA) for natural rubber latex (NRL) was investigated. Both gamma rays and electron beam (EB) were used for vulcanizing NRL with NDDA. The radiation dose of gamma rays, concentration of NDDA required to vulcanize the latex were optimized. 20 kGy radiation dose of gamma rays and 5 phr concentration of NDDA were found optimum to get maximum tensile and related properties. NRL was vulcanized under EB to find out the optimum condition of irradiation with this RVA. The defoamer concentrations, length of irradiation time under EB, concentration of RVA were optimizer by changing various parameters of the EB machine with a constant set of the others. 0.2 phr defoamer concentration, 30 minutes irradiation time and 5 phr concentration of NDDA were found optimum for irradiation of NRL under the EB machine. Effect of low current and optimum volume of latex charged in the reaction vessel suitable for vulcanization at a time were found out. (author)

  12. Toxic mechanisms of 3-monochloropropane-1,2-diol on progesterone production in R2C rat leydig cells.

    Science.gov (United States)

    Sun, Jianxia; Bai, Shun; Bai, Weibin; Zou, Feiyan; Zhang, Lei; Su, Zhijian; Zhang, Qihao; Ou, Shiyi; Huang, Yadong

    2013-10-16

    3-Monochloropropane-1,2-diol (3-MCPD) is a well-known food processing contaminant that has been shown to impede the male reproductive function. However, its mechanism of action remains to be elucidated. In this study, the effects of 3-MCPD on progesterone production were investigated using R2C Leydig cells. 3-MCPD caused concentration-dependent inhibition of cell viability at the IC25, IC50, and IC75 levels of 1.027, 1.802, and 3.160 mM, respectively. Single cell gel/comet assay and atomic force microscopy assay showed that 3-MCPD significantly induced early apoptosis. In addition, 3-MCPD significantly reduced progesterone production by reducing the expression of cytochrome P450 side-chain cleavage enzyme, steroidogenic acute regulatory protein, and 3β-hydroxysteroid dehydrogenase in R2C cells. The change in steroidogenic acute regulatory protein expression was highly consistent with progesterone production. Furthermore, the mitochondrial membrane potential and cAMP significantly decreased.

  13. Structural and vibrational study of a neurotransmitter molecule: Dopamine [4-(2-aminoethyl) benzene-1,2-diol].

    Science.gov (United States)

    Jha, Omkant; Yadav, T K; Yadav, R A

    2018-01-15

    Structural and vibrational studies for the most stable conformer of dopamine {4-(2-Aminoethyl) benzene-1, 2-diol} have been carried out at the DFT/B3LYP/6-311++G** level using the Gaussian 09 software. The IR and Raman spectra have been recorded and analyzed in light of the computed vibrational parameters using the DFT and the PEDs computed with the help of the GAR2PED software. Some of the fundamentals have considerably changed frequencies in going from benzene to dopamine. Except the rocking and wagging modes of the NH 2 group the other four modes are pure group modes. The rocking and wagging modes of the NH 2 group show mixing with the other modes. The two OH stretching vibrations are highly localized modes. The Kekule phenyl ring stretching mode is found to remain almost unchanged. The HOMO-LUMO study suggests the existence of charge transfer within the molecule and the energy gap supports the pharmacological active property of the dopamine molecule. The NBO analysis has been carried out to understand the proper and improper hydrogen bonding. Copyright © 2017. Published by Elsevier B.V.

  14. Dietary exposure of Hong Kong adults to fatty acid esters of 3-monochloropropane-1,2-diol.

    Science.gov (United States)

    Chung, H Y; Chung, Stephen W C; Chan, B T P; Ho, Yuk Yin; Xiao, Ying

    2013-01-01

    A total of 290 individual food samples were collected in Hong Kong, China, for 3-monochloropropane-1,2-diol (3-MCPD) fatty acid esters analysis. Most samples were processed food and in ready-to-eat form. The results show that the levels of 3-MCPD fatty acid esters were high in biscuits, fats and oils, snacks and Chinese pastry with mean bound 3-MCPD levels of 440, 390, 270 and 270 μg kg⁻¹, respectively. The dietary exposures to bound 3-MCPD of average and high adult consumers were estimated to be 0.20 and 0.53 μg kg bw⁻¹ day⁻¹, respectively. The primary toxicological concern of 3-MCPD fatty acid esters is its potential to release 3-MCPD in vivo during digestion in the gastrointestinal tract. 3-MCPD would affect the kidney, the central nervous system and the male reproductive system of rats. Assuming that 100% of the 3-MCPD was released from 3-MCPD fatty acid esters by hydrolysis in the digestive system, the dietary exposures to 3-MCPD for average and high adult consumers were only 10% and 26% of the provisional maximum tolerable daily intake (PMTDI) of 3-MCPD established by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) (2 μg kg bw⁻¹ day⁻¹), respectively. The results suggest that both average and high adult consumers are unlikely to experience major toxicological effects of 3-MCPD.

  15. Lack of effect on rat testicular organogenesis after in utero exposure to 3-monochloropropane-1,2-diol (3-MCPD).

    Science.gov (United States)

    El Ramy, Rosy; Ould Elhkim, Mostafa; Poul, Martine; Forest, Maguelone G; Leduque, Patrick; Le Magueresse-Battistoni, Brigitte

    2006-10-01

    3-Monochloropropane-1,2-diol (3-MCPD) is a food-born contaminant known to display toxic effects on male reproduction, producing infertility in rats and humans. Using the rat as a model, we investigated whether or not testicular organogenesis, which, in the rat species, occurs during the second half of gestation, was at particular risk regarding 3-MCPD toxicity. Pregnant rats were given daily doses of 5, 10 or 25 mg/kg BW of 3-MCPD from days 11.5-18.5 postcoitum (dpc). On 19.5 dpc, testes were removed from fetuses for histological examination and testosterone analysis. Eight genes were selected among the differentiation markers of testicular cell lineages, and their expression was studied by RT-PCR. The levels of 3-MCPD and its main metabolite, beta-chlorolactic acid, were assayed in fetal tissues and dam plasma. Our results show a statistically significant decrease in the mean body weight gain of pregnant rats treated with 10 and 25 mg/kg BW of 3-MCPD. Fetal testes exposed to 3-MCPD exhibited normal histology and produced testosterone at levels that were similar to controls. In addition, 3-MCPD did not alter gene expression in the fetal testes. This lack of effect occurred under conditions where 3-MCPD and beta-chlorolactic acid were found to readily cross the placental barrier and diffuse throughout the fetal tissues. Our findings indicate that 3-MCPD has minimal effect on rat testicular organogenesis.

  16. Optimization of palm oil physical refining process for reduction of 3-monochloropropane-1,2-diol (3-MCPD) ester formation.

    Science.gov (United States)

    Zulkurnain, Musfirah; Lai, Oi Ming; Tan, Soo Choon; Abdul Latip, Razam; Tan, Chin Ping

    2013-04-03

    The reduction of 3-monochloropropane-1,2-diol (3-MCPD) ester formation in refined palm oil was achieved by incorporation of additional processing steps in the physical refining process to remove chloroester precursors prior to the deodorization step. The modified refining process was optimized for the least 3-MCPD ester formation and acceptable refined palm oil quality using response surface methodology (RSM) with five processing parameters: water dosage, phosphoric acid dosage, degumming temperature, activated clay dosage, and deodorization temperature. The removal of chloroester precursors was largely accomplished by increasing the water dosage, while the reduction of 3-MCPD esters was a compromise in oxidative stability and color of the refined palm oil because some factors such as acid dosage, degumming temperature, and deodorization temperature showed contradictory effects. The optimization resulted in 87.2% reduction of 3-MCPD esters from 2.9 mg/kg in the conventional refining process to 0.4 mg/kg, with color and oil stability index values of 2.4 R and 14.3 h, respectively.

  17. Indole-3-acetic acid/diol based pH-sensitive biological macromolecule for antibacterial, antifungal and antioxidant applications.

    Science.gov (United States)

    G, Chitra; D S, Franklin; S, Sudarsan; M, Sakthivel; S, Guhanathan

    2017-02-01

    Indole-3-acetic acid (IAA)/diol based pH-sensitive biopolymeric hydrogels with tunable biological properties (cytotoxicity, anti-oxidant and anti-fungal) have been synthesized via condensation polymerization. The present study focused on the synthesis of heterocyclic hydrogel using citric acid (CA), indole-3-acetic acid (IAA) and diethylene glycol (DEG) by condensation polymerization. The hydrogels revealed a pH-sensitive swelling behaviour, with increased swelling in acidic media, then turns to decreased the swelling in the basic media. The hydrogel samples were tested for antifungal activity against Aspergillus fumigates, Rhizopusoryzae and Candida albicans at different concentrations using ketoconazole as positive control and DMSO as negative control for antifungal activity. Antioxidant activity increasing nature in DPPH than NO radical compared with rutin and confirmed non toxic property using cytotoxicity analysis. The biopolymeric hydrogels were characterized by Fourier transform infrared (FT-IR) spectroscopy, 1 H NMR, 13 C NMR, TGA, DSC followed by scanning electron microscopy (SEM). Such hydrogels with antioxidant properties is recommended for medical applications such as bandages, catheters, drains and tubes to prevent infection. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Soluble epoxide hydrolase activity and pharmacologic inhibition in horses with chronic severe laminitis.

    Science.gov (United States)

    Guedes, A; Galuppo, L; Hood, D; Hwang, S H; Morisseau, C; Hammock, B D

    2017-05-01

    The roles of soluble epoxide hydrolase and lipid mediators in inflammatory and neuropathic pain could be relevant in laminitis pain management. To determine soluble epoxide hydrolase (sEH) activity in the digital laminae, sEH inhibitor potency in vitro, and efficacy of a sEH inhibitor as an adjunct analgesic therapy in chronic laminitic horses. In vitro experiments and clinical case series. sEH activity was measured in digital laminae from euthanised healthy and laminitic horses (n = 5-6/group). Potency of 7 synthetic sEH inhibitors was determined in vitro using equine liver cytosol. One of them (t-TUCB; 0.1 mg/kg bwt i.v. every 24 h) was selected based on potency and stability, and used as adjunct therapy in 10 horses with severe chronic laminitis (Obel grades 2, one horse; 3-4, nine horses). Daily assessments of forelimb lifts, pain scores, physiologic and laboratory examinations were performed before (baseline) and during t-TUCB treatment. Data are presented as mean ± s.d. and 95% confidence intervals (CI). sEH activity in the digital laminae from laminitic horses (0.9±0.6 nmol/min/mg; 95% CI 0.16-1.55 nmol/min/mg) was significantly greater (P = 0.01) than in healthy horses (0.17±0.09 nmol/min/mg; CI 0.07-0.26 nmol/min/mg). t-TUCB as an adjunct analgesic up to 10 days (4.3±3 days) in laminitic horses was associated with significant reduction in forelimb lifts (36±22%; 95% CI 9-64%) and in pain scores (18±23%; 95% CI 2-35%) compared with baseline (P = 0.04). One horse developed gas colic and another corneal vascularisation in a blind eye during treatment. No other significant changes were observed. Absence of control group and evaluator blinding in case series. sEH activity is significantly higher in the digital laminae of actively laminitic compared with healthy horses, and use of a potent inhibitor of equine sEH as adjunct analgesic therapy appears to decrease signs of pathologic pain in laminitic horses. © 2016 EVJ Ltd.

  19. An investigation of endocrine disrupting effects and toxic mechanisms modulated by benzo[a]pyrene in female scallop Chlamys farreri

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Shuangmei; Pan, Luqing, E-mail: panlq@ouc.edu.cn; Sun, Xiaohua

    2013-11-15

    Highlights: •B[a]P disturbed progesterone, 17β-estradiol and testosterone production in scallop. •B[a]P inhibited 3β-HSD, CYP17 and 17β-HSD expression after a 10-day exposure. •B[a]P of lower dose elevated AHR-CYP1A expression but high dose B[a]P inhibited them. •ER and vitellogenin transcription was consistent with AHR after B[a]P exposure. •B[a]P exposure induced relatively developmental delay and impairment of ovary. -- Abstract: The purpose of this study was to investigate the endocrine disrupting effects induced by benzo[a]pyrene (B[a]P) and explore the underlying mechanisms in mollusks. In this study, sexually mature female Chlamys farreri were exposed to benzo[a]pyrene for 10 days at four different concentrations as 0, 0.025, 0.5 and 10 μg/L. Sex steroids were identified and quantified by electrochemiluminescence immunoassay (ECLIA) method and results showed that exposure to B[a]P exerts great suppression on 17β-estradiol, testosterone production and disrupts progesterone levels in ovary. Transcription of genes were detected and measured by real-time RT-PCR. It showed that at day 10 B[a]P inhibited 3β-HSD, CYP17 and 17β-HSD mRNA expression in a dose-dependent manner, which suggests that they could be potential targets of B[a]P that disrupt steroidogenic machinery. Moreover, 0.025 μg/L B[a]P activated transcription of aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), CYP1A1 and estrogen receptor (ER), while 10 μg/L B[a]P suppressed all of them. The consistency of their responses to B[a]P exposure implies that AHR action may be involved in invertebrate CYP regulation and ER transcription despite of unknown mechanisms. Additionally, B[a]P exposure could induce ovarian impairment and developmental delay in C. farreri. Overall, sensitivity of C. farreri to endocrine disruption and toxicity suggests that C. farreri is a suitable species for study of endocrine-disrupting effects in marine invertebrates. This study will form a

  20. An investigation of endocrine disrupting effects and toxic mechanisms modulated by benzo[a]pyrene in female scallop Chlamys farreri

    International Nuclear Information System (INIS)

    Tian, Shuangmei; Pan, Luqing; Sun, Xiaohua

    2013-01-01

    Highlights: •B[a]P disturbed progesterone, 17β-estradiol and testosterone production in scallop. •B[a]P inhibited 3β-HSD, CYP17 and 17β-HSD expression after a 10-day exposure. •B[a]P of lower dose elevated AHR-CYP1A expression but high dose B[a]P inhibited them. •ER and vitellogenin transcription was consistent with AHR after B[a]P exposure. •B[a]P exposure induced relatively developmental delay and impairment of ovary. -- Abstract: The purpose of this study was to investigate the endocrine disrupting effects induced by benzo[a]pyrene (B[a]P) and explore the underlying mechanisms in mollusks. In this study, sexually mature female Chlamys farreri were exposed to benzo[a]pyrene for 10 days at four different concentrations as 0, 0.025, 0.5 and 10 μg/L. Sex steroids were identified and quantified by electrochemiluminescence immunoassay (ECLIA) method and results showed that exposure to B[a]P exerts great suppression on 17β-estradiol, testosterone production and disrupts progesterone levels in ovary. Transcription of genes were detected and measured by real-time RT-PCR. It showed that at day 10 B[a]P inhibited 3β-HSD, CYP17 and 17β-HSD mRNA expression in a dose-dependent manner, which suggests that they could be potential targets of B[a]P that disrupt steroidogenic machinery. Moreover, 0.025 μg/L B[a]P activated transcription of aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), CYP1A1 and estrogen receptor (ER), while 10 μg/L B[a]P suppressed all of them. The consistency of their responses to B[a]P exposure implies that AHR action may be involved in invertebrate CYP regulation and ER transcription despite of unknown mechanisms. Additionally, B[a]P exposure could induce ovarian impairment and developmental delay in C. farreri. Overall, sensitivity of C. farreri to endocrine disruption and toxicity suggests that C. farreri is a suitable species for study of endocrine-disrupting effects in marine invertebrates. This study will form a

  1. Mechanisms of interaction of radiation with matter

    International Nuclear Information System (INIS)

    Geacintov, N.E.; Pope, M.

    1993-01-01

    This project is concerned with the mechanisms by which polynuclear aromatic (PNA) compounds on the one hand, and ionizing radiation on the other, cause damage to DNA. PNA compounds constitute an important class of environmental pollutants derived from energy-related sources which, upon metabolic activation to diolepoxide derivatives, produce bulky PNA-DNA lesions interfere with the normal DNA replication and transcription processes, and give rise to mutations and the initiation of tumors. Chiral and other stereochemical effects play a key role in determining the biological effects of a given PNA diol epoxide and the potentially mutagenic lesions which are formed. New and efficient methods for synthesizing stereochemically pure and precisely positioned PNA diol epoxide-DNA lesions in small DNA fragments are reported here. We have elucidated the structures of three stereoisomeric benzo[a]pyrene diol epoxide-DNA adducts. How these adducts affect on DNA polymerase fidelity, transcription, and DNA repair are currently being investigated with respect to detailed structure-biological activity correlations. Spectroscopic techniques such as circular dichroism, fluorescence, and photoionization play an important role in the characterizations of the PNA adducts. A new method was developed for measuring the lifetimes as well as the energies of picosecond duration electronically excited states. Using this technique, it is proposed that short-lived (15 ps) charge-transfer (CT) states in the PNA compound tetracene are activated by a 20 ps laser pulse; an unusual external photoemission echo do to the recombination of CT states is observed 85 ps after the pulse

  2. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David [Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, 40450 Selangor Darul Ehsan (Malaysia)

    2015-08-28

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB{sup −}4 harboring phaC{sub cs} from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two T{sub g}s present for the blends and both remain constant for different compositions which corresponds to the T{sub g}s of the parent polymers. This indicates that the blends are immiscible.

  3. Engineering characterisation of epoxidized natural rubber-modified hot-mix asphalt.

    Directory of Open Access Journals (Sweden)

    Ramez A Al-Mansob

    Full Text Available Road distress results in high maintenance costs. However, increased understandings of asphalt behaviour and properties coupled with technological developments have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, polymers have become extremely popular as modifiers to improve the performance of the asphalt mix. This study investigates the performance characteristics of epoxidized natural rubber (ENR-modified hot-mix asphalt. Tests were conducted using ENR-asphalt mixes prepared using the wet process. Mechanical testing on the ENR-asphalt mixes showed that the resilient modulus of the mixes was greatly affected by testing temperature and frequency. On the other hand, although rutting performance decreased at high temperatures because of the increased elasticity of the ENR-asphalt mixes, fatigue performance improved at intermediate temperatures as compared to the base mix. However, durability tests indicated that the ENR-asphalt mixes were slightly susceptible to the presence of moisture. In conclusion, the performance of asphalt pavement can be enhanced by incorporating ENR as a modifier to counter major road distress.

  4. Gamma irradiation effect on acrylated-epoxidized soybean oil: polymerization and characterization

    International Nuclear Information System (INIS)

    Hernandez-lopez, S.; Sanchez-Mendieta, V.; Vigueras-Santiago, E.; Martin Del Campo-Lopez, E.; Urena-Nunez, F.

    2006-01-01

    In this work we present the gamma-irradiation dose effect on acrylated-epoxidized soybean oil (AESO). AESO started to polymerize at 12 kGy and at higher doses (24, 110 and 340 kGy) there is an increase in cross-linking reaction without degradation, thermal or structural changes. Polymeric products were glassy, thermosetting, insoluble, which no longer melt upon heating, and no Tg was observed between -30 to 300 deg C. These polymers were obtained with a specific shape and different properties in comparison with the thermal PolyAESO (rubber) due to higher cross-linking achieved by gamma irradiation. NMR, FT-IR and DSC techniques evidenced these facts. Friction and scratching properties were dependent of irradiation dose. Due to an increase in cross-linking density, lower friction values, reached at high doses (110 and 340 kGy), were accompanied by a lower scratching penetration depth in these polymers. Gamma-ray polymerization could be an alternative and efficient method for in situ synthesis of thermosetting polymers, copolymers and composites with given shapes, controlled polymerization degrees and optimized properties

  5. Cobaltoporphyrin-Catalyzed CO 2 /Epoxide Copolymerization: Selectivity Control by Molecular Design

    KAUST Repository

    Anderson, Carly E.; Vagin, Sergei I.; Xia, Wei; Jin, Hanpeng; Rieger, Bernhard

    2012-01-01

    A series of cobalt(III) chloride porphyrin complexes of the general formula 5,10,15,20-tetra(p-alkoxy)phenylporphyrin cobalt chloride (4b-e) and the related 5,10,15,20-tetra(p-nitro)phenylporphyrin cobalt chloride (4f) are presented and their reactivity toward propylene oxide (PO)/CO 2 coupling/copolymerization is explored. While the nitro-substituted complex (4f), in conjunction with an onium salt, shows moderate activity toward cyclization, the 4b-e/onium systems show superior copolymerization activity in comparison to tetraphenylporphyrin Co(III) chloride (4a) with high selectivity and conversion to poly(propylene carbonate) (PPC). A comprehensive copolymerization behavior study of the alkoxy-substituted porphyrin complexes 4b-e in terms of reaction temperature and CO 2 pressure is presented. Complexes bearing longer alkoxy-substituents demonstrate the highest polymerization activity and molecular weights, however all substituted catalyst systems display a reduced tolerance to increased temperature with respect to PPC formation. Studies of the resulting polymer microstructures show excellent head-to-tail epoxide incorporation and near perfectly alternating poly(carbonate) character at lower polymerization temperatures. © 2012 American Chemical Society.

  6. Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

    Science.gov (United States)

    Xu, Tiwen; Jia, Zhixin; Luo, Yuanfang; Jia, Demin; Peng, Zheng

    2015-02-01

    The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress-strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

  7. Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tiwen [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Jia, Zhixin, E-mail: zxjia@scut.edu.cn [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Yuanfang; Jia, Demin [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Peng, Zheng [Agricultural Product Processing Research Institute, Chinese Academy of Tropical Agriculture Sciences, Zhanjiang 524001 (China)

    2015-02-15

    Highlights: • Substantiate the ring open reaction between Si-OH of silica and epoxy groups of ENR. • ENR can act as a bridge between NR and silica to enhance the interfacial interaction. • As a modifier, ENR gets the potential to be used in the tread of green tire for improving the wet skid resistance apparently. - Abstract: The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress–strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

  8. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    International Nuclear Information System (INIS)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David

    2015-01-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB − 4 harboring phaC cs from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two T g s present for the blends and both remain constant for different compositions which corresponds to the T g s of the parent polymers. This indicates that the blends are immiscible

  9. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Science.gov (United States)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David

    2015-08-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB-4 harboring phaCcs from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two Tgs present for the blends and both remain constant for different compositions which corresponds to the Tgs of the parent polymers. This indicates that the blends are immiscible.

  10. Occurrence of urea-based soluble epoxide hydrolase inhibitors from the plants in the order Brassicales.

    Directory of Open Access Journals (Sweden)

    Seiya Kitamura

    Full Text Available Recently, dibenzylurea-based potent soluble epoxide hydrolase (sEH inhibitors were identified in Pentadiplandra brazzeana, a plant in the order Brassicales. In an effort to generalize the concept, we hypothesized that plants that produce benzyl glucosinolates and corresponding isothiocyanates also produce these dibenzylurea derivatives. Our overall aim here was to examine the occurrence of urea derivatives in Brassicales, hoping to find biologically active urea derivatives from plants. First, plants in the order Brassicales were analyzed for the presence of 1, 3-dibenzylurea (compound 1, showing that three additional plants in the order Brassicales produce the urea derivatives. Based on the hypothesis, three dibenzylurea derivatives with sEH inhibitory activity were isolated from maca (Lepidium meyenii roots. Topical application of one of the identified compounds (compound 3, human sEH IC50 = 222 nM effectively reduced pain in rat inflammatory pain model, and this compound was bioavailable after oral administration in mice. The biosynthetic pathway of these urea derivatives was investigated using papaya (Carica papaya seed as a model system. Finally, a small collection of plants from the Brassicales order was grown, collected, extracted and screened for sEH inhibitory activity. Results show that several plants of the Brassicales order could be potential sources of urea-based sEH inhibitors.

  11. Adhesion property of epoxidized natural rubber (ENR-based adhesives containing calcium carbonate

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The adhesion property (i.e. viscosity, loop tack and peel strength of epoxidized natural rubber (ENR 25 and ENR 50 grade-based pressure-sensitive adhesive was studied in the presence of calcium carbonate. The range of calcium carbonate loaded was from 10 to 50 parts per hundred parts of rubber (phr. Coumarone-indene resin was used as the tackifier and its concentration was fixed at 80 phr. Toluene was chosen as the solvent throughout the investigation. The substrates (PET film/paper were coated with the adhesive using a SHEEN hand coater at a coating thickness of 60 µm. Viscosity of the adhesive was measured by a HAAKE Rotary Viscometer whereas loop tack and peel strength were determined by a Llyod Adhesion Tester operating at 30 cm/min. Results show that viscosity of ENR-based adhesives increases gradually with increase in calcium carbonate loading due to the concentration effect of the filler. However, for loop tack and peel strength, it passes through a maximum at 30 phr calcium carbonate, an observation which is attributed to the optimum wettability of adhesive on the substrate at this adhesive composition. ENR 25-based adhesive consistently exhibits higher adhesion property than ENR 50 for all calcium carbonate loadings studied.

  12. Enantioselective polymerization of epoxides using biaryl-linked bimetallic cobalt catalysts: A mechanistic study

    KAUST Repository

    Ahmed, Syud M.; Poater, Albert; Childers, M. Ian; Widger, Peter C B; Lapointe, Anne M.; Lobkovsky, Emil B.; Coates, Geoffrey W.; Cavallo, Luigi

    2013-01-01

    The enantioselective polymerization of propylene oxide (PO) using biaryl-linked bimetallic salen Co catalysts was investigated experimentally and theoretically. Five key aspects of this catalytic system were examined: (1) the structural features of the catalyst, (2) the regio- and stereoselectivity of the chain-growth step, (3) the probable oxidation and electronic state of Co during the polymerization, (4) the role of the cocatalyst, and (5) the mechanism of monomer enchainment. Several important insights were revealed. First, density functional theory (DFT) calculations provided detailed structural information regarding the regio- and stereoselective chain-growth step. Specifically, the absolute stereochemistry of the binaphthol linker determines the enantiomer preference in the polymerization, and the interaction between the salen ligand and the growing polymer chain is a fundamental aspect of enantioselectivity. Second, a new bimetallic catalyst with a conformationally flexible biphenol linker was synthesized and found to enantioselectively polymerize PO, though with lower enantioselectivity than the binaphthol linked catalysts. Third, DFT calculations revealed that the active form of the catalyst has two active exo anionic ligands (chloride or carboxylate) and an endo polymer alkoxide which can ring-open an adjacent cobalt-coordinated epoxide. Fourth, calculations showed that initiation is favored by an endo chloride ligand, while propagation is favored by the presence of two exo carboxylate ligands. © 2013 American Chemical Society.

  13. Structure-Based Optimization of Arylamides as Inhibitors of Soluble Epoxide Hydrolase

    Energy Technology Data Exchange (ETDEWEB)

    Eldrup, Anne B.; Soleymanzadeh, Fariba; Taylor, Steven J.; Muegge, Ingo; Farrow, Neil A.; Joseph, David; McKellop, Keith; Man, Chuk C.; Kukulka, Alison; De Lombaert, Stephane; (Boehringer)

    2009-11-04

    Inhibition of soluble epoxide hydrolase (sEH) is hypothesized to lead to an increase in circulating levels of epoxyeicosatrienoic acids, resulting in the potentiation of their in vivo pharmacological properties. As part of an effort to identify inhibitors of sEH with high and sustained plasma exposure, we recently performed a high throughput screen of our compound collection. The screen identified N-(3,3-diphenyl-propyl)-nicotinamide as a potent inhibitor of sEH. Further profiling of this lead revealed short metabolic half-lives in microsomes and rapid clearance in the rat. Consistent with these observations, the determination of the in vitro metabolic profile of N-(3,3-diphenyl-propyl)-nicotinamide in rat liver microsomes revealed extensive oxidative metabolism and a propensity for metabolite switching. Lead optimization, guided by the analysis of the solid-state costructure of N-(3,3-diphenyl-propyl)-nicotinamide bound to human sEH, led to the identification of a class of potent and selective inhibitors. An inhibitor from this class displayed an attractive in vitro metabolic profile and high and sustained plasma exposure in the rat after oral administration.

  14. Efficient epoxidation over cyanocobalamine containing SBA-15 organic-inorganic nanohybrids

    Energy Technology Data Exchange (ETDEWEB)

    Karimi, Z. [Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Mahjoub, A.R., E-mail: mahjouba@modares.ac.ir [Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of)

    2010-05-01

    SBA-15 mesoporous silica is synthesized using triblock copolymer P123 surfactant and chemically modified by aminopropyl, thiol, ammonium and sulfonic acid functional groups. Functionalization is performed via post synthesize method using 3-aminopropyltriethoxysilane (APTES) or 3-mercatopropyl trimethoxysilane (MPTMS) precursor. The as synthesized mesoporous systems are applied for immobilization of cyanocobalamine. Functionalization effectively improves sorption properties of the supports, while different functional groups exert different effects. The organic-inorganic mesoporous materials are characterized via X-ray diffraction (XRD), nitrogen adsorption and desorption, transmission electron microscopy (TEM), FT-IR and inductively coupled plasma-optical emission (ICP). The newly synthesized systems exhibit high catalytic activity for heterogeneous epoxidation of cyclooctene in presence of hydrogen peroxide. Reaction conditions are optimized, effect of functional groups on performance of the catalysts is taken into consideration and reusability of the designed heterogeneous systems is studied. Systems with chemically modified supports are shown to be more efficient and stable catalysts however; chemical nature of functional groups plays a crucial role.

  15. Mechanical, Thermal and Morphological Properties of Poly(lactic acid/Epoxidized Palm Olein Blend

    Directory of Open Access Journals (Sweden)

    Hazimah Abu Hassan

    2012-10-01

    Full Text Available Poly(lactic acid (PLA is known to be a useful material in substituting the conventional petroleum-based polymer used in packaging, due to its biodegradability and high mechanical strength. Despite the excellent properties of PLA, low flexibility has limited the application of this material. Thus, epoxidized palm olein (EPO was incorporated into PLA at different loadings (1, 2, 3, 4 and 5 wt% through the melt blending technique and the product was characterized. The addition of EPO resulted in a decrease in glass transition temperature and an increase of elongation-at-break, which indicates an increase in the PLA chain mobility. PLA/EPO blends also exhibited higher thermal stability than neat PLA. Further, the PLA/1 wt% EPO blend showed enhancement in the tensile, flexural and impact properties. This is due to improved interaction in the blend producing good compatible morphologies, which can be revealed by Scanning Electron Microscopy (SEM analysis. Therefore, PLA can be efficiently plasticized by EPO and the feasibility of its use as flexible film for food packaging should be considered.

  16. Preferential hydroxylation over epoxidation catalysis by a horseradish peroxidase mutant: a cytochrome P450 mimic.

    Science.gov (United States)

    de Visser, Sam P

    2007-10-25

    Density functional theory calculations are presented on the catalytic properties of a horseradish peroxidase mutant whereby the axial nitrogen atom is replaced by phosphorus. This mutant has never been studied experimentally and only one theoretical report on this system is known (de Visser, S. P. J. Phys. Chem. B 2006, 110, 20759-20761). Thus, a one-atom substitution in horseradish peroxidase changes the properties of the catalytic center of the enzyme to more cytochrome P450-type qualities. In particular, the phosphorus-substituted horseradish peroxidase mutant reacts with substrates via a unique reactivity pattern, whereby alkanes are regioselectively hydroxylated even in the presence of a double bond. Reaction barriers of propene epoxidation and hydroxylation are almost identical to ones observed for a cytochrome P450 catalyst and significantly higher than those obtained for a horseradish peroxidase catalyst. It is shown that the regioselectivity difference is entropy and thermally driven and that the electron-transfer processes that occur during the reaction mechanism follow cytochrome P450-type patterns in the hydroxylation reaction.

  17. Hybrid thermosets from vinyl ester resin and acrylated epoxidized soybean oil (AESO

    Directory of Open Access Journals (Sweden)

    2011-01-01

    Full Text Available A series of hybrids composed of styrene crosslinkable vinyl ester (VE and acrylated epoxidized soybean oil (AESO were produced via free radical-induced crosslinking. The VE/AESO ratio was changed between 75/25 and 25/75 wt%. Moreover, to support phase grafting the VE/AESO = 50/50 wt% hybrid was modified with phthalic anhydride in various amounts (1, 5 and 10 wt%. The structure of the hybrid systems was investigated by dynamic mechanical thermal analysis (DMTA, differential scanning calorimetry (DSC, and atomic force microscopy (AFM. The properties of the systems were assessed by static flexural and fracture mechanical tests. The resistance to thermal degradation was inspected by thermogravimetric analysis (TGA. The results suggested that the hybrids have an interpenetrating network (IPN structure. With increasing AESO content the stiffness (modulus, strength and glass transition temperature (Tg of the hybrids decreased, whereas their ductility increased. Phthalic anhydride caused an adverse trend. Both the fracture toughness and fracture energy increased with increasing AESO content. They were less affected by adding phthalic anhydride phase couplant. Interestingly, the hybrids outperformed the parent VE and AESO in respect to resistance to thermal degradation.

  18. Evaluation of permanent deformation and durability of epoxidized natural rubber modified asphalt mix

    Science.gov (United States)

    Al-Mansob, Ramez A.; Ismail, Amiruddin; Rahmat, Riza Atiq O. K.; Nazri Borhan, Muhamad; Alsharef, Jamal M. A.; Albrka, Shaban Ismael; Rehan Karim, Mohamed

    2017-09-01

    The road distresses have caused too much in maintenance cost. However, better understandings of the behaviours and properties of asphalt, couples with greater development in technology, have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, modifiers such as polymers are the most popular modifiers used to improve the performance of asphalt mix. This study was conducted to investigate the use of epoxidized natural rubber (ENR) to be mixed with asphalt mix. Tests were conducted to investigate the performance characteristics of ENR-asphalt mixes, where the mixes were prepared according to the wet process. Mechanical testing on the ENR-asphalt mixes have demonstrated that the asphalt mix permanent deformation performance at high temperature was found to be improved compared to the base mixes. However, the durability studies have indicated that ENR-asphalt mixes are slightly susceptible with the presence of moisture. The durability of the ENR-asphalt mixes were found to be enhanced in term of permanent deformation at high and intermediate temperatures compared to the base asphalt mixes. As conclusion, asphalt pavement performance can be enhanced by using ENR as modifier to face the major road distresses.

  19. Enantioselective polymerization of epoxides using biaryl-linked bimetallic cobalt catalysts: A mechanistic study

    KAUST Repository

    Ahmed, Syud M.

    2013-12-18

    The enantioselective polymerization of propylene oxide (PO) using biaryl-linked bimetallic salen Co catalysts was investigated experimentally and theoretically. Five key aspects of this catalytic system were examined: (1) the structural features of the catalyst, (2) the regio- and stereoselectivity of the chain-growth step, (3) the probable oxidation and electronic state of Co during the polymerization, (4) the role of the cocatalyst, and (5) the mechanism of monomer enchainment. Several important insights were revealed. First, density functional theory (DFT) calculations provided detailed structural information regarding the regio- and stereoselective chain-growth step. Specifically, the absolute stereochemistry of the binaphthol linker determines the enantiomer preference in the polymerization, and the interaction between the salen ligand and the growing polymer chain is a fundamental aspect of enantioselectivity. Second, a new bimetallic catalyst with a conformationally flexible biphenol linker was synthesized and found to enantioselectively polymerize PO, though with lower enantioselectivity than the binaphthol linked catalysts. Third, DFT calculations revealed that the active form of the catalyst has two active exo anionic ligands (chloride or carboxylate) and an endo polymer alkoxide which can ring-open an adjacent cobalt-coordinated epoxide. Fourth, calculations showed that initiation is favored by an endo chloride ligand, while propagation is favored by the presence of two exo carboxylate ligands. © 2013 American Chemical Society.

  20. Pharmacological inhibition of soluble epoxide hydrolase or genetic deletion reduces diclofenac-induced gastric ulcers.

    Science.gov (United States)

    Goswami, Sumanta Kumar; Rand, Amelia Ann; Wan, Debin; Yang, Jun; Inceoglu, Bora; Thomas, Melany; Morisseau, Christophe; Yang, Guang-Yu; Hammock, Bruce D

    2017-07-01

    This research was conducted to evaluate the hypothesis that gastric ulcers caused by the NSAID diclofenac sodium (DCF) can be prevented by the soluble epoxide hydrolase inhibitor TPPU. Mice were administered a single dose of 10, 30 or 100mg/kg of DCF. Once an ulcerative dose of DCF was chosen, mice were pretreated with TPPU for 7days at 0.1mg/kg to evaluate anti-ulcer effects of the sEH inhibitor on anatomy, histopathology, pH, inflammatory markers and epithelial apoptosis of stomachs. Diclofenac caused ulceration of the stomach at a dose of 100mg/kg and a time post dose of 6h. Ulcers generated under these conditions were associated with a significant increase in the levels of TNF-α and IL-6 in serum and increased apoptosis compared to control mice. Pretreatment with TPPU resulted in a decrease of ulceration in mice treated with DCF with a significant decrease in the level of apoptosis, TNF-α and IL-6 in the serum in comparison to diclofenac-treated mice. TPPU did not affect the pH of the stomach, whereas omeprazole elevated the pH of the stomach as expected. A similar anti-ulcer effect was observed in sEH gene knockout mice treated with DCF. The sEH inhibitor TPPU decreases the NSAID-induced stomach ulcers. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Soluble epoxide hydrolase inhibitors of indolinone alkaloids and phenolic derivatives from Cimicifuga dahurica (Turcz.) Maxim.

    Science.gov (United States)

    Thao, Nguyen Phuong; Luyen, Bui Thi Thuy; Lee, Ji Sun; Kim, Jang Hoon; Kim, Young Ho

    2017-04-15

    The aim of this study was to search for potential therapeutic agents by identifying novel inhibitors of soluble epoxide hydrolase (sEH) from natural plants using an in silico approach. We found that an ethanolic extract from the roots of Cimicifuga dahurica (Turcz.) Maxim. significantly inhibited sEH in vitro. In a phytochemical investigation using assay-guided fractionation of the dichloromethane extract of C. dahurica, we isolated two new indolinone alkaloids (5 and 6) and five related constituents (1-4, and 7) and established their structures based on an extensive analysis using 1D and 2D NMR, and MS methods. All of the isolated compounds inhibited sEH enzymatic activity in a dose-dependent manner, with IC 50 values ranging from 0.8±0.0 to 2.8±0.4μM. A kinetic analysis of compounds 1-7 revealed that compound 2 was non-competitive; 1, 3, and 7 were mixed-type; and 4-6 were competitive inhibitors. Molecular docking was employed to further elucidate their receptor-ligand binding characteristics. These results demonstrated that compounds from C. dahurica are potential sEH inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Genetic Deletion of Soluble Epoxide Hydrolase Attenuates Inflammation and Fibrosis in Experimental Obstructive Nephropathy

    Directory of Open Access Journals (Sweden)

    Chin-Wei Chiang

    2015-01-01

    Full Text Available Soluble epoxide hydrolase (sEH is abundantly expressed in kidney and plays a potent role in regulating inflammatory response in inflammatory diseases. However, the role of sEH in progression of chronic kidney diseases such as obstructive nephropathy is still elusive. In current study, wild-type (WT and sEH deficient (sEH−/− mice were subjected to the unilateral ureteral obstruction (UUO surgery and the kidney injury was evaluated by histological examination, western blotting, and ELISA. The protein level of sEH in kidney was increased in UUO-treated mice group compared to nonobstructed group. Additionally, UUO-induced hydronephrosis, renal tubular injury, inflammation, and fibrosis were ameliorated in sEH−/− mice with the exception of glomerulosclerosis. Moreover, sEH−/− mice with UUO showed lower levels of inflammation-related and fibrosis-related protein such as monocyte chemoattractant protein-1, macrophage inflammatory protein-2, interleukin-1β (IL-1β, IL-6, inducible nitric oxide synthase, collagen 1A1, and α-actin. The levels of superoxide anion radical and hydrogen peroxide as well as NADPH oxidase activity were also decreased in UUO kidneys of sEH−/− mice compared to that observed in WT mice. Collectively, our findings suggest that sEH plays an important role in the pathogenesis of experimental obstructive nephropathy and may be a therapeutic target for the treatment of obstructive nephropathy-related diseases.

  3. Development of UV Curable Overprint Varnishes (OPV) Formulation from Epoxidized Palm Olein Acrylated (EPOLA)

    International Nuclear Information System (INIS)

    Nurul Huda Mudri; Nik Ghazali Nik Salleh; Mek Zah Salleh

    2014-01-01

    The synthesis procedure of Epoxidized Palm Olein Acrylated (EPOLA) has been established by Radiation Curing and Synthesis Group. The quality control test such as acid value, oxirane oxygen content and Fourier- Transform Infra Red (FTIR) were done to monitor the synthesis process. The completion of synthesis process was observed via FTIR with the presence of hydroxyl (-OH) absorption between 3440-3480 cm -1 and an absorption of acrylate groups at 819 cm -1 . The EPOLA was then coated on glass plate and irradiated with UV light. It was found that EPOLA is curable under exposure of UV light and has potential in the application of Overprint Varnishes (OPV). Several formulations have been developed which basically consist of oligomer, monomer, photo initiator EPOLA and additives. The formulations were then coated on black and white paper and irradiated under UV light. The speed of the conveyer was set at 5 m/ min and 20 m/ min during irradiation and the number of passes for the coated substrate to be cured is recorded. The physical characterization such as adhesion and curing rate were observed compared with desirable finished products. (author)

  4. Meta-analysis of microsomal epoxide hydrolase gene polymorphism and risk of hepatocellular carcinoma.

    Science.gov (United States)

    Zhong, Jian-Hong; Xiang, Bang-De; Ma, Liang; You, Xue-Mei; Li, Le-Qun; Xie, Gui-Sheng

    2013-01-01

    Hepatocarcinogenesis is a complex process that may be influenced by many factors, including polymorphism in microsomal epoxide hydrolase (mEH). Previous work suggests an association between the Tyr113His and His139Arg mEH polymorphisms and susceptibility to hepatocellular carcinoma (HCC), but the results have been inconsistent. PubMed, EMBASE, Google Scholar and the Chinese National Knowledge Infrastructure databases were systematically searched to identify relevant studies. A meta-analysis was performed to examine the association between Tyr113His and His139Arg mEH polymorphism and susceptibility to HCC. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Eleven studies were included in the meta-analysis, involving 1,696 HCC cases and 3,600 controls. The 113His- mEH allele was significantly associated with increased risk of HCC based on allelic contrast (OR = 1.35, 95% CI = 1.04-1.75, p = 0.02), homozygote comparison (OR = 1.65, 95% CI = 1.07-2.54, p = 0.02) and a recessive genetic model (OR = 1.54, 95% CI = 1.21-1.96, penvironment to modulate risk of HCC. Further large and well-designed studies are needed to confirm these conclusions.

  5. Warfarin traps human vitamin K epoxide reductase in an intermediate state during electron transfer

    Science.gov (United States)

    Shen, Guomin; Cui, Weidong; Zhang, Hao; Zhou, Fengbo; Huang, Wei; Liu, Qian; Yang, Yihu; Li, Shuang; Bowman, Gregory R.; Sadler, J. Evan; Gross, Michael L.; Li, Weikai

    2017-01-01

    Although warfarin is the most widely used anticoagulant worldwide, the mechanism by which warfarin inhibits its target, human vitamin K epoxide reductase (hVKOR), remains unclear. Here we show that warfarin blocks a dynamic electron-transfer process in hVKOR. A major fraction of cellular hVKOR is at an intermediate redox state of this process containing a Cys51-Cys132 disulfide, a characteristic accommodated by a four-transmembrane-helix structure of hVKOR. Warfarin selectively inhibits this major cellular form of hVKOR, whereas disruption of the Cys51-Cys132 disulfide impairs warfarin binding and causes warfarin resistance. Relying on binding interactions identified by cysteine alkylation footprinting and mass spectrometry coupled with mutagenesis analysis, we are able to conduct structure simulations to reveal a closed warfarin-binding pocket stabilized by the Cys51-Cys132 linkage. Understanding the selective warfarin inhibition of a specific redox state of hVKOR should enable the rational design of drugs that exploit the redox chemistry and associated conformational changes in hVKOR. PMID:27918545

  6. "Green" composites from renewable resources: preparation of epoxidized soybean oil and flax fiber composites.

    Science.gov (United States)

    Liu, Zengshe; Erhan, Sevim Z; Akin, Danny E; Barton, Franklin E

    2006-03-22

    In recent years there has been considerable interest in using natural plant fibers as reinforcements for plastics. The motivation includes cost, performance enhancement, weight reduction, and environment concerns. High performance flax fiber could potentially substitute for glass or carbon fibers as reinforcements for plastics. This study reports the "green" composites obtained from a mixture of epoxidized soybean oil and epoxy resin, 1,1,1-tris(p-hydroxyphenyl)ethane triglycidyl ether (THPE-GE), reinforced with flax fiber. The compression molding method is used for making the composites. Curing agents triethylenetetramine and diethylenetriamine provide better physical properties of the composites than Jeffamine agents D-230 and EDR-148. Both the flexural modulus and the tensile modulus of the composites increase as the amount of THPE-GE increases. The flexural modulus increased at a fiber content of fiber content until a maximum at 13.5 wt %, and then it decreases. The flax fiber length affected the mechanical properties of the composites: the longer the fiber length, the better are the mechanical properties observed.

  7. Cobaltoporphyrin-Catalyzed CO 2 /Epoxide Copolymerization: Selectivity Control by Molecular Design

    KAUST Repository

    Anderson, Carly E.

    2012-09-11

    A series of cobalt(III) chloride porphyrin complexes of the general formula 5,10,15,20-tetra(p-alkoxy)phenylporphyrin cobalt chloride (4b-e) and the related 5,10,15,20-tetra(p-nitro)phenylporphyrin cobalt chloride (4f) are presented and their reactivity toward propylene oxide (PO)/CO 2 coupling/copolymerization is explored. While the nitro-substituted complex (4f), in conjunction with an onium salt, shows moderate activity toward cyclization, the 4b-e/onium systems show superior copolymerization activity in comparison to tetraphenylporphyrin Co(III) chloride (4a) with high selectivity and conversion to poly(propylene carbonate) (PPC). A comprehensive copolymerization behavior study of the alkoxy-substituted porphyrin complexes 4b-e in terms of reaction temperature and CO 2 pressure is presented. Complexes bearing longer alkoxy-substituents demonstrate the highest polymerization activity and molecular weights, however all substituted catalyst systems display a reduced tolerance to increased temperature with respect to PPC formation. Studies of the resulting polymer microstructures show excellent head-to-tail epoxide incorporation and near perfectly alternating poly(carbonate) character at lower polymerization temperatures. © 2012 American Chemical Society.

  8. Ag-Cu Bimetallic Nanoparticles Prepared by Microemulsion Method as Catalyst for Epoxidation of Styrene

    Directory of Open Access Journals (Sweden)

    Hong-Kui Wang

    2012-01-01

    Full Text Available Ag/Cu bimetallic nanocatalysts supported on reticulate-like γ-alumina were prepared by a microemulsion method using N2H4·H2O as the reducing agent. The catalysts were activated by calcination followed with hydrogen reduction at 873K, and the properties were confirmed using various characterization techniques. Compared with metal oxides particles, Ag-Cu particles exhibited smaller sizes (<5 nm after calcination in H2 at 873K. XPS results indicated that the binding energies changed with the Ag/Cu ratios, suggesting that increasing the copper content gave both metals a greater tendency to lose electrons. Furthermore, Ag-Cu bimetallic nanoparticles supported on γ-alumina showed better catalytic activity on the epoxidation of styrene as compared with the corresponding monometallic silver or copper. The styrene oxide selectivity could reach 76.6% at Ag/Cu molar ratio of 3/1, while the maximum conversion (up to 94.6% appeared at Ag/Cu molar ratio of 1/1 because of the maximum interaction between silver and copper.

  9. Oil-in-Water Emulsions Stabilized by Saponified Epoxidized Soybean Oil-Grafted Hydroxyethyl Cellulose.

    Science.gov (United States)

    Huang, Xujuan; Li, Qiaoguang; Liu, He; Shang, Shibin; Shen, Minggui; Song, Jie

    2017-05-03

    An oil-in-water emulsion stabilized by saponified epoxidized soybean oil-grafted hydroxyethyl cellulose (H-ESO-HEC) was investigated. By using an ultrasonic method, oil-in-water emulsions were prepared by blending 50 wt % soybean oil and 50 wt % H-ESO-HEC aqueous suspensions. The influence of H-ESO-HEC concentrations on the properties of oil-in-water emulsions was examined. The H-ESO-HEC concentrations in the aqueous phase varied from 0.02 to 0.40 wt %. When the H-ESO-HEC concentration was 0.4 wt %, the emulsion remained stable for >80 days. The mean droplet sizes of the emulsions decreased by increasing the H-ESO-HEC concentration and extending the ultrasonic time. The adsorption amounts of H-ESO-HEC at the oil-water interface increased when the H-ESO-HEC concentrations in the aqueous phase increased. The rheological property revealed that the apparent viscosity of the H-ESO-HEC-stabilized oil-in-water emulsions increased when the H-ESO-HEC concentrations increased. Steady flow curves indicated an interfacial film formation in the emulsions. The evolution of G', G″, and tan η indicated the predominantly elastic behaviors of all the emulsions.

  10. Thermodynamics of coil-hyperbranched poly(styrene-b-acrylated epoxidized soybean oil) block copolymers

    Science.gov (United States)

    Lin, Fang-Yi; Hohmann, Austin; Hernández, Nacú; Cochran, Eric

    Here we present the phase behavior of a new type of coil-hyperbranched diblock copolymer: poly(styrene- b-acrylated epoxidized soybean oil), or PS-PAESO. PS-PAESO is an example of a biorenewable thermoplastic elastomer (bio-TPE). To date, we have shown that bio-TPEs can be economical commercial substitutes for their petrochemically derived analogues--such as poly(styrene- b-butadiene- b-styrene) (SBS)--in a range of applications including pressure sensitive adhesives and bitumen modification. From a polymer physics perspective, PS-PAESO is an interesting material in that it couples a linear coil-like block with a highly branched block. Thus in contrast to the past five decades of studies on linear AB diblock copolymers, coil-hyperbranched block copolymers are relatively unknown to the community and can be expected to deviate substantially from the standard ``universal'' phase behavior in the AB systems. To explore these new materials, we have constructed a library of PS-PAESO materials spanning a range of molecular weight and composition values. The phase transition behavior and the morphology information will be interpreted by isochronal temperature scanning in dynamic shear rheology, small angle X-ray scattering and the corresponding transmission electron microscopy.

  11. Preparation of Non-Woven Fiber Mats by Mixture of PVC and Epoxidized Natural Rubber

    International Nuclear Information System (INIS)

    Muhammad Hariz Othman; Mahathir Mohamed; Dahlan Mohd

    2014-01-01

    Eletrospun non-woven fibre mats prepared from ENR modified PVC were successfully fabricated at ambient temperature by electro spinning method. Liquid epoxidized natural rubber (LENR) was used because it is easier to handle compared to dried ENR. PVC was mixed with LENR based on 3 different ratios (9:1, 8:2 and 7:3). The effect of ENR on electrospinnibality of PVC was investigated.The morphologies and thermal properties of the electro span fibre mats were characterized and assessed using scanning calorimetry (DSC). The polymer solution concentration 16 aut % formed a diameter of the fibres were mainly affected by the addition of natural rubber and weight ratio of the solution. The diameter of the fibres also decreased with increasing amount of LENR in the solution. Thermal degradation involved two-step degradation with the first degradation representing the dehydro chlorination of PVC to form polyene and followed by the decomposition of LENR and the polyene.Addition of LENR into the sample caused the T g of electro spun fibre mats of PVC/LENR to shift toward lower temperature. (author)

  12. Nitration of benzo[a]pyrene adsorbed on coal fly ash particles by nitrogen dioxide: role of thermal activation.

    Science.gov (United States)

    Kristovich, Robert L; Dutta, Prabir K

    2005-09-15

    Nitration of benzo[a]pyrene (BaP) by nitrogen dioxide (NO2) adsorbed on the surface of thermally activated coal fly ash and model aluminosilicate particles led to the formation of nitrobenzo[a]pyrenes as verified by extraction and gas chromatography/mass spectrometry (GC/MS). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was utilized to follow the nitration reaction on the surface of zeolite Y. Nitrobenzo[a]pyrene formation was observed along with the formation of nitrous acid and nitrate species. The formation of the BaP radical cation was also observed on thermally activated aluminosilicate particles by electron spin resonance (ESR) spectroscopy. On the basis of GC/MS, DRIFTS, and ESR spectroscopy results, a mechanism of nitration involving intermediate BaP radical cations generated on thermally activated aluminosilicate particles is proposed. These observations have led to the hypothesis that nitration of adsorbed polyaromatic hydrocarbons on coal fly ash by reaction with nitrogen oxides can occur in the smokestack, but with the aging of the fly ash particles, the extent of the nitration reaction will be diminished.

  13. Prediction of benzo[a]pyrene content of smoked sausage using back-propagation artificial neural network.

    Science.gov (United States)

    Chen, Yan; Cai, Kezhou; Tu, Zehui; Nie, Wen; Ji, Tuo; Hu, Bing; Chen, Conggui; Jiang, Shaotong

    2017-11-29

    Benzo[a]pyrene (BaP), a potent mutagen and carcinogen, is reported to be present in processed meat products and, in particular, in smoked meat. However, few methods exist for predictive determination of the BaP content of smoked meats such as sausage. In this study, an artificial neural network (ANN) model based on the back-propagation (BP) algorithm was used to predict the BaP content of smoked sausage. The results showed that the BP network based on the Levenberg-Marquardt algorithm was the best suited for creating a nonlinear map between the input and output parameters. The optimal network structure was 3-7-1 and the learning rate was 0.6. This BP-ANN model allowed for accurate predictions, with the correlation coefficients (R) for the experimentally determined training, validation, test and global data sets being 0.94, 0.96, 0.95 and 0.95 respectively. The validation performance was 0.013, suggesting that the proposed BP-ANN may be used to predictively detect the BaP content of smoked meat products. An effective predictive model was constructed for estimation of the BaP content of smoked sausage using ANN modeling techniques, which shows potential to predict the BaP content in smoked sausage. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. Effects of benzo(a)pyrene on the skeletal development of Sebastiscus marmoratus embryos and the molecular mechanism involved

    International Nuclear Information System (INIS)

    He Chengyong; Zuo Zhenghong; Shi Xiao; Li Ruixia; Chen Donglei; Huang Xin; Chen Yixin; Wang Chonggang

    2011-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants, which have been known to be carcinogenic and teratogenic. However, the skeletal development toxicity of PAHs and the mechanism involved remain unclear. In fishes, the neurocranial and craniofacial skeleton develop as cartilage. The signaling molecules of hedgehog (Hh) family play crucial roles in regulating skeletal development. In the present study, rockfish (Sebastiscus marmoratus) embryos were exposed to benzo(a)pyrene (BaP) for 7 days at environmental levels (0.05, 0.5 and 5 nmol/L) which resulted in craniofacial skeleton deformities. BaP exposure reduced the cell proliferation activity in the craniofacial skeleton as detected by quantitative PCR and in situ hybridization. The expression of Sonic hedgehog (Shh), rather than Indian hedgehog (Ihh), was down-regulated in the craniofacial skeleton in the 0.5 and 5 nmol/L groups. Consistent with the Shh results, the expression of Ptch1 and Gli2 was decreased by BaP exposure and BMP4 was presented on changes in the 0.5 and 5 nmol/L groups. These results suggested that BaP could impair the expression and function of Shh signaling pathway, perturbing the proliferation of chondrocytes and so disturbing craniofacial skeletal development.

  15. Effect of Soil Aging on the Phytoremediation Potential of Zea mays in Chromium and Benzo[a]Pyrene Contaminated Soils.

    Science.gov (United States)

    Chigbo, Chibuike

    2015-06-01

    This study compared the phytoremediation potential of Zea mays in soil either aged or freshly amended with chromium (Cr) and benzo[a]pyrene (B[a]P). Z. mays showed increased shoot biomass in aged soils than in freshly spiked soils. The shoot biomass in contaminated soils increased by over 50% in aged soil when compared to freshly amended soils, and over 29% more Cr was accumulated in the shoot of Z. mays in aged soil than in freshly amended soil. Planting Z. mays in aged soil helped in the dissipation of more than 31% B[a]P than in freshly spiked soil, but in the absence of plants, there seemed to be no difference between the dissipation rates of B[a]P in freshly and aged co-contaminated soil. Z. mays seemed to enhance the simultaneous removal of Cr and B[a]P in aged soil than in freshly spiked soil and hence can be a good plant choice for phytoremediation of co-contaminated soils.

  16. Screening of Lactobacillus strains for their ability to bind benzo(a)pyrene and the mechanism of the process.

    Science.gov (United States)

    Zhao, Hongfei; Zhou, Fang; Qi, Yeqiong; Dziugan, Piotr; Bai, Fengling; Walczak, Piotr; Zhang, Bolin

    2013-09-01

    In order to investigate the binding ability of Lactobacillus strains to Benzo(a)pyrene (BaP), 15 strains were analysed. L. plantarum CICC 22135 and L. pentosus CICC 23163 exhibited high efficiency in removing BaP from aqueous medium; the binding rates were 66.76% and 64.31%, respectively. This process was affected by temperature, incubation time and pH, and cell viability was not necessary for the binding ability. Additionally, both strains, especially strain CICC 23163 showed high specificity in binding BaP. The cell-BaP complexes were stable in aqueous medium. The mechanism of binding was investigated by examining the binding ability of different components of the microorganism cells. The results revealed that peptidoglycans played an important role in binding BaP and its structural integrity was required. Consequently, we proposed that the mechanism of this process was a physisorption and peptidoglycan was the main binding site. These two strains may be used for dietary detoxification in human diet and animal feed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Molecular characterization of ABC transporters in marine ciliate, Euplotes crassus: Identification and response to cadmium and benzo[a]pyrene.

    Science.gov (United States)

    Kim, Hokyun; Yim, Bora; Kim, Jisoo; Kim, Haeyeon; Lee, Young-Mi

    2017-11-30

    ATP-binding cassette (ABC) transporters participate in transporting various substances, including xenobiotics, in or out of cells. However, their genetic information and function in ciliates remain still unclear. In this study, we sequenced and characterized two ABC transporter genes (EcABCB and EcABCC), and investigated the effect of cadmium (Cd) and benzo[a]pyrene (B[a]P) on their function and gene expression, using efflux assay and real-time reverse transcription-polymerase chain reaction (qRT-PCR), respectively, in the marine ciliate, Euplotes crassus. Sequencing analysis and efflux assay showed that EcABCB and EcABCC are typical ABC transporters, possessing conserved function. Exposure to Cd (≥5mg/L) and B[a]P (≥50.5μg/L) enhanced accumulation of a substrate. A significant increase in the expression of EcABCB and EcABC mRNA was observed at lower concentration in response to Cd and B[a]P. Our findings indicate that Cd and B[a]P could inhibit the efflux function of ABC transporters, leading to cellular toxicity in the ciliate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Quantitative determination of benzo[a]pyrene in foodstuffs using benzo[a]pyrene[G-3H

    International Nuclear Information System (INIS)

    Masuda, Yoshito; Shimamura, Kyoko; Yano, Hiroshige

    1977-01-01

    A method for quantitative determination of nano gram level of benzo(a)pyrene (BP) in foodstuffs using tritiated BP( 3 H-BP) was described. Extracts from foodstuffs, having been added a certain amount of 3 H-BP, were fractionated by column chromatography on Florisil, and thinlayer chromatography on acetylated cellulose. Concentration and radio activity of BP in the final fraction were determined by fluorescence spectrometry and liquid scintillation. Recovery ratio of each experiment was obtained by comparing the radio activities of added 3 H-BP and separated BP. Concentration of BP in the sample analyzed was calculated from the amount of isolated BP and the recovery ratio in each experiment. A quantitative limit of BP by this method was 0.2 ppb when 50 g of sample was used. By this method, contents of BO in each sample of Tenpura oil, salad oil, flour, and polished rice were determined as 0.6, 0.2, 0.1 and < 0.1 ppb on average, respectively. (auth.)

  19. Can we use modelling methodologies to assess airborne benzo[a]pyrene from biomonitors? A comprehensive evaluation approach

    Science.gov (United States)

    Ratola, N.; Jiménez-Guerrero, P.

    2015-09-01

    Biomonitoring data available on levels of atmospheric polycyclic aromatic hydrocarbons (PAHs) in pine needles from the Iberian Peninsula was used to estimate air concentrations of benzo[a]pyrene (BaP) and, at the same time, fuelled the comparison with chemistry transport model representations. Simulations with the modelling system WRF + CHIMERE were validated against data from the European Monitoring and Evaluation Programme (EMEP) air sampling network and using modelled atmospheric concentrations as a consistent reference in order to compare the performance of vegetation-to-air estimating methods. A spatial and temporal resolution of 9 km and 1 h was implemented. The field-based database relied on a pine needles sampling scheme comprising 33 sites in Portugal and 37 sites in Spain complemented with the BaP measurements available from the EMEP sites. The ability of pine needles to act as biomonitoring markers for the atmospheric concentrations of BaP was estimated converting the levels obtained in pine needles into air concentrations by six different approaches, one of them presenting realistic concentrations when compared to the modelled atmospheric values. The justification for this study is the gaps still existing in the knowledge of the life cycles of semi-volatile organic compounds (SVOCs), particularly the partition processes between air and vegetation. The strategy followed in this work allows the definition of the transport patterns (e.g. dispersion) established by the model for atmospheric concentrations and the estimated values in vegetation.

  20. Interconnection of Key Microbial Functional Genes for Enhanced Benzo[a]pyrene Biodegradation in Sediments by Microbial Electrochemistry.

    Science.gov (United States)

    Yan, Zaisheng; He, Yuhong; Cai, Haiyuan; Van Nostrand, Joy D; He, Zhili; Zhou, Jizhong; Krumholz, Lee R; Jiang, He-Long

    2017-08-01

    Sediment microbial fuel cells (SMFCs) can stimulate the degradation of polycyclic aromatic hydrocarbons in sediments, but the mechanism of this process is poorly understood at the microbial functional gene level. Here, the use of SMFC resulted in 92% benzo[a]pyrene (BaP) removal over 970 days relative to 54% in the controls. Sediment functions, microbial community structure, and network interactions were dramatically altered by the SMFC employment. Functional gene analysis showed that c-type cytochrome genes for electron transfer, aromatic degradation genes, and extracellular ligninolytic enzymes involved in lignin degradation were significantly enriched in bulk sediments during SMFC operation. Correspondingly, chemical analysis of the system showed that these genetic changes resulted in increases in the levels of easily oxidizable organic carbon and humic acids which may have resulted in increased BaP bioavailability and increased degradation rates. Tracking microbial functional genes and corresponding organic matter responses should aid mechanistic understanding of BaP enhanced biodegradation by microbial electrochemistry and development of sustainable bioremediation strategies.

  1. Effects of benzo(a)pyrene on the skeletal development of Sebastiscus marmoratus embryos and the molecular mechanism involved

    Energy Technology Data Exchange (ETDEWEB)

    He Chengyong [Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen (China); Zuo Zhenghong [Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen (China); Shi Xiao; Li Ruixia; Chen Donglei; Huang Xin; Chen Yixin [Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen (China); Wang Chonggang, E-mail: cgwang@xmu.edu.cn [Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen (China)

    2011-01-25

    Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants, which have been known to be carcinogenic and teratogenic. However, the skeletal development toxicity of PAHs and the mechanism involved remain unclear. In fishes, the neurocranial and craniofacial skeleton develop as cartilage. The signaling molecules of hedgehog (Hh) family play crucial roles in regulating skeletal development. In the present study, rockfish (Sebastiscus marmoratus) embryos were exposed to benzo(a)pyrene (BaP) for 7 days at environmental levels (0.05, 0.5 and 5 nmol/L) which resulted in craniofacial skeleton deformities. BaP exposure reduced the cell proliferation activity in the craniofacial skeleton as detected by quantitative PCR and in situ hybridization. The expression of Sonic hedgehog (Shh), rather than Indian hedgehog (Ihh), was down-regulated in the craniofacial skeleton in the 0.5 and 5 nmol/L groups. Consistent with the Shh results, the expression of Ptch1 and Gli2 was decreased by BaP exposure and BMP4 was presented on changes in the 0.5 and 5 nmol/L groups. These results suggested that BaP could impair the expression and function of Shh signaling pathway, perturbing the proliferation of chondrocytes and so disturbing craniofacial skeletal development.

  2. A glucose-responsive pH-switchable bioelectrocatalytic sensor based on phenylboronic acid-diol specificity

    International Nuclear Information System (INIS)

    Gao, Peiyi; Wang, Zhihua; Yang, Lele; Ma, Tengfei; Yang, Ling; Guo, Qianqiong; Huang, Shasheng

    2015-01-01

    Graphical abstract: A pH-switchable bioelectrocatayltic sensor was developed, which exhibited an obvious anodic current in acidic conditions as “ON” state, yet a prohibited signal in alkaline conditions as “OFF” state. With the change of pH and/or the presence of glucose, our proposed biosensor produced the corresponding amplified signal, providing a better sensitivity. - Abstract: Aminophenylboronic acid moieties were covalently grafted onto mercaptobenzoic acid moieties, and glucose oxidase was then immobilized through boronic acid-diol specific recognition to form a pH-sensitive electrosensor switching between pH 5.8 and pH 8.0 base solution. Using potassium ferricyanide as electroactive probe, the response was intensified in acidic condition while hindered in alkaline condition. The sharp and stable contrast in current was performed alternately upon the change of pH like a “pH switch”. In the presence of glucose, the response to glucose was further amplified catalytically by glucose oxidase on “ON” state, while electron transfer was inhibited on “OFF” state. Furthermore, when our sensor was on “ON” state, it showed a good linearity ranging from 0 to 30 μmol L −1 of glucose, with a detection limit of 348 nmol L −1 (S/B = 3) and a dynamic range extending to 50 μmol L −1 . Glucose-responsive, pH-switchable and catalytically-amplified, our biosensor provided a new method for the detection of glucose in the form of pH switch in human serum sample, and was promising to more complicated environment

  3. Novel Magnetic Microprobe with Benzoboroxole-Modified Flexible Multisite Arm for High-Efficiency cis-Diol Biomolecule Detection.

    Science.gov (United States)

    Chen, Guosheng; Huang, Siming; Kou, Xiaoxue; Zhang, Jin'ge; Wang, Fuxin; Zhu, Fang; Ouyang, Gangfeng

    2018-03-06

    With regard to regulating a variety of biological events, including molecular recognition, signal transduction, cell adhesion, and immune response, cis-diol biomolecules, such as saccharides and glycoproteins, play vital roles. However, saccharides and glycoproteins in living systems usually exist in very low abundance, along with abundant interfering components. High-efficiency detection of saccharides and glycoproteins is a challenging yet highly impactful area of research. Herein, we reported a novel magnetic microprobe with a benzoboroxole-modified flexible multisite arm (PEG 2000-grafted PAMAM dendrimers; the microprobe was denoted as BFMA-MNP) for high-efficiency saccharides detection. The extraction capacity was significantly improved by ∼2 orders of magnitude, because of the integration of the enhanced hydrophilicity and multivalency effects in benzoboroxoles and the enhanced accessibility of the binding sites within the PEG 2000-grafted PAMAM dendrimers. As a result, the proposed approach possessed several advantages, compared with previous boronic acid-based methods, including ultrahigh sensitivity (limit of detection was <1 ng/mL), wide linear range (ranged from 0.5 μM to 2000 μM), and applicable in physiological pH condition. Furthermore, we established a general BFMA-MNP/glycoproteins/AuNPs sandwich assay to realize the visual glycoprotein qualitative screening for the first time. The unique sandwich assay possessed the dual nature of the magnetic separation by BFMA-MNPs and specific coloration by citrate-coated AuNPs. This visual sandwich assay enabled fast differentiation of the existence of glycoproteins in complicated samples without any advanced instruments. We believe the proposed BFMA-MNP microprobe herein will advance the ideas to detect and identify trace saccharides and glycoproteins in important fields such as glycomics and glycoproteomics.

  4. Altered susceptibility of an obese rat model to 13-week subchronic toxicity induced by 3-monochloropropane-1,2-diol.

    Science.gov (United States)

    Toyoda, Takeshi; Cho, Young-Man; Akagi, Jun-Ichi; Mizuta, Yasuko; Matsushita, Kohei; Nishikawa, Akiyoshi; Imaida, Katsumi; Ogawa, Kumiko

    2017-01-01

    3-Monochloropropane-1,2-diol (3-MCPD) is a heat-induced food contaminant that has been shown to be a nongenotoxic renal carcinogen. Although the toxicity of 3-MCPD has been widely investigated for decades, there is a further concern that 3-MCPD might exert more potent toxicity in high-risk population with underlying diseases such as hyperlipidemia associated with obesity. In the present study, we performed a 13-week subchronic toxicity study for 3-MCPD using an obesity rat model to investigate the differences in susceptibility between obese and normal individuals. Male F344 and obese Zucker (lean and fatty) rats were administered 0, 9, 28.5, 90, 285, or 900 ppm 3-MCPD in drinking water for 13 weeks. 3-MCPD treatment decreased body weight gain, increased relative kidney weights, induced anemia, and induced epithelial cell necrosis in epididymal ducts in all 3 strains. The degrees of epididymal damage were higher in F344 and lean rats than in fatty rats, while renal toxicity was most potent in F344 rats and comparable in lean and fatty rats. In contrast, the hematology data indicated that anemia was worse in fatty rats than in F344 and lean rats, and a significant decrease in hematopoietic cells in the bone marrow was observed only in fatty rats. The no-observed-adverse-effect level was estimated to be 28.5 ppm in all 3 strains for 3-MCPD. These results suggested that obese Zucker rats may be more susceptible to 3-MCPD-dependent toxicity in the hematopoietic tissues than their lean counterparts.

  5. Partial molar volumes of organic solutes in water. XXIV. Selected alkane-α,ω-diols at temperatures T = 298 K to 573 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Cibulka, Ivan; Hnědkovský, Lubomír

    2013-01-01

    Highlights: • Standard molar volumes of three alkane-α,ω-diols (C 5 , C 8 , C 9 ) in water are presented. • Data were obtained in the range T from (298 to 573) K and p up to 30 MPa. • Dependences on carbon atom number, temperature, and pressure are analysed. -- Abstract: Density data for dilute aqueous solutions of three alkane-α,ω-diols (pentane-1,5-diol, octane-1,8-diol, nonane-1,9-diol) are presented together with standard molar volumes (partial molar volumes at infinite dilution) calculated from the experimental data. The measurements were performed at temperatures from T = 298 K up to T = 573 K. Experimental pressures were slightly above the saturation vapour pressure of water, and (15 and 30) MPa. The data were obtained using a high-temperature high-pressure flow vibrating-tube densimeter. Measured standard molar volumes were combined with data previously published for other members of the homologous series and discussed. Experimental standard molar volumes were correlated as a function of temperature and pressure using an empirical polynomial function. Dependences of standard molar volumes on temperature and pressure were analysed. Contributions of the methylene group to the standard molar volume were also evaluated and discussed

  6. NMR study of the epoxidation of liquid hydrolyzed poly-butadiene and meta-chloro-per-benzoic acid; Estudo atraves de RMN da reacao de epoxidacao de polibutadieno liquido hidroxilado (PBLH) e acido m-cloro perbenzoico (AMCPB)

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Marcelo [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Akcelrud, L [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica; Menezes, Sonia Cabral de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1994-12-31

    This work presents a study concerning the selectivity of the different configurations of the double bond present in liquid hydrolyzed poly-butadiene towards the epoxidation reaction with meta-chloro-per-benzoic acid through hydrogen-1, carbon-13 NMR aiming the production of new materials, varying the epoxidation level 12 refs., 7 figs., 4 tabs.

  7. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 82, Revision 1 (FGE.82Rev1): Consideration of Epoxides evaluated by the JECFA (65 th meeting)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present consideration concerns a group of five epoxides evaluated by the JECFA at the 65th meeting in 2005. This revision is made due to inclusion of one additional substance, beta-ionone epoxide [FL-no: 07.170], cleared...

  8. Multi-wall carbon nanotubes supported molybdenyl acetylacetonate: Efficient and highly reusable catalysts for epoxidation of alkenes with tert-butyl hydroperoxide

    Energy Technology Data Exchange (ETDEWEB)

    Esnaashari, Fariba [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Moghadam, Majid, E-mail: moghadamm@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Mirkhani, Valiollah, E-mail: mirkhani@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Tangestaninejad, Shahram; Mohammadpoor-Baltork, Iraj; Khosropour, Ahmad Reza; Zakeri, Maryam [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2012-11-15

    Efficient epoxidation of olefins catalyzed by MoO{sub 2}(acac){sub 2} supported on amines functionalized MWCNTs is reported. The MWCNTs bearing carboxylic acid groups were modified with 2-aminophenol and 2-aminothiophenol. These amine-MWCNTs act as bidentate ligand for attachment of Mo catalyst. These catalysts were characterized by elemental analysis, scanning electron microscopy, FT-IR and diffuse reflectance UV-Vis spectroscopic methods. The prepared catalysts were used for efficient epoxidation of different alkenes such as cyclic and linear ones with tert-butyl hydroperoxide in refluxing 1,2-dichloroethane. These heterogeneous catalysts can be reused several times without significant loss of their catalytic activity. Highlights: Black-Right-Pointing-Pointer Supporting of molybdenyl acetylacetonate on amine-modified MWCNTs. Black-Right-Pointing-Pointer Heterogeneous catalysts were prepared. Black-Right-Pointing-Pointer These catalysts were highly efficient in the epoxidation of alkenes with TBHP. Black-Right-Pointing-Pointer Makes the catalysts reusable.

  9. Multi-wall carbon nanotubes supported molybdenyl acetylacetonate: Efficient and highly reusable catalysts for epoxidation of alkenes with tert-butyl hydroperoxide

    International Nuclear Information System (INIS)

    Esnaashari, Fariba; Moghadam, Majid; Mirkhani, Valiollah; Tangestaninejad, Shahram; Mohammadpoor-Baltork, Iraj; Khosropour, Ahmad Reza; Zakeri, Maryam

    2012-01-01

    Efficient epoxidation of olefins catalyzed by MoO 2 (acac) 2 supported on amines functionalized MWCNTs is reported. The MWCNTs bearing carboxylic acid groups were modified with 2-aminophenol and 2-aminothiophenol. These amine–MWCNTs act as bidentate ligand for attachment of Mo catalyst. These catalysts were characterized by elemental analysis, scanning electron microscopy, FT-IR and diffuse reflectance UV–Vis spectroscopic methods. The prepared catalysts were used for efficient epoxidation of different alkenes such as cyclic and linear ones with tert-butyl hydroperoxide in refluxing 1,2-dichloroethane. These heterogeneous catalysts can be reused several times without significant loss of their catalytic activity. Highlights: ► Supporting of molybdenyl acetylacetonate on amine-modified MWCNTs. ► Heterogeneous catalysts were prepared. ► These catalysts were highly efficient in the epoxidation of alkenes with TBHP. ► Makes the catalysts reusable.

  10. Steviamine, a new class of indolizidine alkaloid [(1R,2S,3R,5R,8aR-3-hydroxymethyl-5-methyloctahydroindolizine-1,2-diol hydrobromide

    Directory of Open Access Journals (Sweden)

    Amber L. Thompson

    2009-11-01

    Full Text Available X-ray crystallographic analysis of the title hydrobromide salt, C10H20N+·Br−, of (1R,2S,3R,5R,8aR-3-hydroxymethyl-5-methyloctahydroindolizine-1,2-diol defines the absolute and relative stereochemistry at the five chiral centres in steviamine, a new class of polyhydroxylated indolizidine alkaloid isolated from Stevia rebaudiana (Asteraceae leaves. In the crystal structure, molecules are linked by intermolecular O—H...Br and N—H...Br hydrogen bonds, forming double chains around the twofold screw axes along the b-axis direction. Intramolecular O—H...O interactions occur.

  11. Multipoint attachment to a support protects enzyme from inactivation by organic solvents: alpha-Chymotrypsin in aqueous solutions of alcohols and diols.

    Science.gov (United States)

    Mozhaev, V V; Sergeeva, M V; Belova, A B; Khmelnitsky, Y L

    1990-03-25

    Inactivation of alpha-chymotrypsin in aqueous solutions of alcohols and diols proceeds both reversibly and irreversibly. Reversible loss of the specific enzyme activity results from conformational changes (unfolding) of the enzyme detected by fluorescence spectroscopy. Multipoint covalent attachment to the matrix of polyacryl-amide gel by copolymerization method stabilizes alpha-chymotrypsin from denaturation by alcohols, the stabilizing effect increasing with the number of bonds between the protein and the support. Immobilization protects the enzyme also from irreversible inactivation by organic solvents resulting from bimolecular aggregation and autolysis.

  12. Hydroformylation of olefins and reductive carbonylation of aryl halides with syngas formed ex situ from dehydrogenative decarbonylation of hexane-1,6-diol

    DEFF Research Database (Denmark)

    Christensen, Stig Holden; Olsen, Esben Paul Krogh; Rosenbaum, Jascha

    2014-01-01

    A variety of primary alcohols have been investigated as convenient substrates for the ex situ delivery of carbon monoxide and molecular hydrogen in a two-chamber reactor. The gaseous mixture is liberated in one chamber by an iridium-catalysed dehydrogenative decarbonylation of the alcohol...... and then consumed in the other chamber in either a rhodium-catalysed hydroformylation of olefins or a palladium-catalysed reductive carbonylation of aryl halides. Hexane-1,6-diol was found to be the optimum alcohol for both reactions where moderate to excellent yields were obtained of the product aldehydes...

  13. Synthesis, characterization and impedance spectroscopy study of magnetite/epoxidized natural rubber nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Tan, W.L. [Nanoscience Research Laboratory, School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Abu Bakar, M., E-mail: bmohamad@usm.my [Nanoscience Research Laboratory, School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2013-06-05

    Highlights: ► The Fe{sub 3}O{sub 4}/ENR nanocomposites have not been synthesized and reported. ► Nanocomposites were obtained via in situ synthesis of Fe{sub 3}O{sub 4} in the presence of ENR. ► The use of ENR enabled control of the size of Fe{sub 3}O{sub 4} particles to <20 nm. ► Conductivity of the nanocomposites increases with the increase in Fe{sub 3}O{sub 4} loading. ► The equivalent circuit for the nanocomposites is proposed and discussed. -- Abstract: The magnetite (Fe{sub 3}O{sub 4}) particles were synthesized in situ in the presence of epoxidized natural rubber (ENR) to produce the various Fe{sub 3}O{sub 4}/ENR nanocomposites. The X-ray diffraction (XRD) analysis confirmed the existence of Fe{sub 3}O{sub 4} particles in the composites. The FTIR and DSC studies suggested that no chemical interactions between the particles and the matrix. The SEM and X-mapping micrographs revealed that the Fe{sub 3}O{sub 4} particles were distributed within the ENR matrix. The ENR matrix exerts control on the Fe{sub 3}O{sub 4} particles with a size of <20 nm in the composites. The Fe{sub 3}O{sub 4} particles also affect the electrical properties of the composites. Impedance spectroscopy studies show that the electrical conductivity of the nanocomposites increases with the increase in Fe{sub 3}O{sub 4} loading in the composite. The equivalent circuit for the Fe{sub 3}O{sub 4}/ENR nanocomposites is proposed and discussed.

  14. Tissue Expressions of Soluble Human Epoxide Hydrolase-2 Enzyme in Patients with Temporal Lobe Epilepsy.

    Science.gov (United States)

    Ahmedov, Merdin Lyutviev; Kemerdere, Rahsan; Baran, Oguz; Inal, Berrin Bercik; Gumus, Alper; Coskun, Cihan; Yeni, Seher Naz; Eren, Bulent; Uzan, Mustafa; Tanriverdi, Taner

    2017-10-01

    We sought to simply demonstrate how levels of soluble human epoxide hydrolase-2 show changes in both temporal the cortex and hippocampal complex in patients with temporal lobe epilepsy. A total of 20 patients underwent anterior temporal lobe resection due to temporal lobe epilepsy. The control group comprised 15 people who died in traffic accidents or by falling from a height, and their autopsy findings were included. Adequately sized temporal cortex and hippocampal samples were removed from each patient during surgery, and the same anatomic structures were removed from the control subjects during the autopsy procedures. Each sample was stored at -80°C as rapidly as possible until the enzyme assay. The temporal cortex in the epilepsy patients had a significantly higher enzyme level than did the temporal cortex of the control group (P = 0.03). Correlation analysis showed that as the enzyme level increases in the temporal cortex, it also increases in the hippocampal complex (r 2  = 0.06, P = 0.00001). More important, enzyme tissue levels showed positive correlations with seizure frequency in both the temporal cortex and hippocampal complex in patients (r 2  = 0.7, P = 0.00001 and r 2  = 0.4, P = 0.003, respectively). The duration of epilepsy was also positively correlated with the hippocampal enzyme level (r 2  = 0.06, P = 0.00001). Soluble human epoxy hydrolase enzyme-2 is increased in both lateral and medial temporal tissues in temporal lobe epilepsy. Further studies should be conducted as inhibition of this enzyme has resulted in a significant decrease in or stopping of seizures and attenuated neuroinflammation in experimental epilepsy models in the current literature. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Vitamin K epoxide reductase complex subunit 1 (Vkorc1 haplotype diversity in mouse priority strains

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    Kohn Michael H

    2008-12-01

    Full Text Available Abstract Background Polymorphisms in the vitamin K-epoxide reductase complex subunit 1 gene, Vkorc1, could affect blood coagulation and other vitamin K-dependent proteins, such as osteocalcin (bone Gla protein, BGP. Here we sequenced the Vkorc1 gene in 40 mouse priority strains. We analyzed Vkorc1 haplotypes with respect to prothrombin time (PT and bone mineral density and composition (BMD and BMC; phenotypes expected to be vitamin K-dependent and represented by data in the Mouse Phenome Database (MPD. Findings In the commonly used laboratory strains of Mus musculus domesticus we identified only four haplotypes differing in the intron or 5' region sequence of the Vkorc1. Six haplotypes differing by coding and non-coding polymorphisms were identified in the other subspecies of Mus. We detected no significant association of Vkorc1 haplotypes with PT, BMD and BMC within each subspecies of Mus. Vkorc1 haplotype sequences divergence between subspecies was associated with PT, BMD and BMC. Conclusion Phenotypic variation in PT, BMD and BMC within subspecies of Mus, while substantial, appears to be dominated by genetic variation in genes other than the Vkorc1. This was particularly evident for M. m. domesticus, where a single haplotype was observed in conjunction with virtually the entire range of PT, BMD and BMC values of all 5 subspecies of Mus included in this study. Differences in these phenotypes between subspecies also should not be attributed to Vkorc1 variants, but should be viewed as a result of genome wide genetic divergence.

  16. Meta-analysis of microsomal epoxide hydrolase gene polymorphism and risk of hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Jian-Hong Zhong

    Full Text Available BACKGROUND: Hepatocarcinogenesis is a complex process that may be influenced by many factors, including polymorphism in microsomal epoxide hydrolase (mEH. Previous work suggests an association between the Tyr113His and His139Arg mEH polymorphisms and susceptibility to hepatocellular carcinoma (HCC, but the results have been inconsistent. METHODS: PubMed, EMBASE, Google Scholar and the Chinese National Knowledge Infrastructure databases were systematically searched to identify relevant studies. A meta-analysis was performed to examine the association between Tyr113His and His139Arg mEH polymorphism and susceptibility to HCC. Odds ratios (ORs and 95% confidence intervals (95% CIs were calculated. RESULTS: Eleven studies were included in the meta-analysis, involving 1,696 HCC cases and 3,600 controls. The 113His- mEH allele was significantly associated with increased risk of HCC based on allelic contrast (OR = 1.35, 95% CI = 1.04-1.75, p = 0.02, homozygote comparison (OR = 1.65, 95% CI = 1.07-2.54, p = 0.02 and a recessive genetic model (OR = 1.54, 95% CI = 1.21-1.96, p<0.001, while individuals carrying the Arg139Arg mEH genotype had no association with increased or decreased risk of HCC. CONCLUSION: The 113His- allele polymorphism in mEH may be a risk factor for hepatocarcinogenesis, while the mEH 139Arg- allele may not be a risk or protective factor. There is substantial evidence that mEH polymorphisms interact synergistically with other genes and the environment to modulate risk of HCC. Further large and well-designed studies are needed to confirm these conclusions.

  17. Inhibition of the soluble epoxide hydrolase promotes albuminuria in mice with progressive renal disease.

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    Oliver Jung

    2010-08-01

    Full Text Available Epoxyeicotrienoic acids (EETs are cytochrome P450-dependent anti-hypertensive and anti-inflammatory derivatives of arachidonic acid, which are highly abundant in the kidney and considered reno-protective. EETs are degraded by the enzyme soluble epoxide hydrolase (sEH and sEH inhibitors are considered treatment for chronic renal failure (CRF. We determined whether sEH inhibition attenuates the progression of CRF in the 5/6-nephrectomy model (5/6-Nx in mice. 5/6-Nx mice were treated with a placebo, an ACE-inhibitor (Ramipril, 40 mg/kg, the sEH-inhibitor cAUCB or the CYP-inhibitor fenbendazole for 8 weeks. 5/6-Nx induced hypertension, albuminuria, glomerulosclerosis and tubulo-interstitial damage and these effects were attenuated by Ramipril. In contrast, cAUCB failed to lower the blood pressure and albuminuria was more severe as compared to placebo. Plasma EET-levels were doubled in 5/6 Nx-mice as compared to sham mice receiving placebo. Renal sEH expression was attenuated in 5/6-Nx mice but cAUCB in these animals still further increased the EET-level. cAUCB also increased 5-HETE and 15-HETE, which derive from peroxidation or lipoxygenases. Similar to cAUCB, CYP450 inhibition increased HETEs and promoted albuminuria. Thus, sEH-inhibition failed to elicit protective effects in the 5/6-Nx model and showed a tendency to aggravate the disease. These effects might be consequence of a shift of arachidonic acid metabolism into the lipoxygenase pathway.

  18. Altered soluble epoxide hydrolase-derived oxylipins in patients with seasonal major depression: An exploratory study.

    Science.gov (United States)

    Hennebelle, Marie; Otoki, Yurika; Yang, Jun; Hammock, Bruce D; Levitt, Anthony J; Taha, Ameer Y; Swardfager, Walter

    2017-06-01

    Many cytochrome p450-derived lipids promote resolution of inflammation, in contrast to their soluble epoxide hydrolase(sEH)-derived oxylipin breakdown products. Here we compare plasma oxylipins and precursor fatty acids between seasons in participants with major depressive disorder with seasonal pattern (MDD-s). Euthymic participants with a history of MDD-s recruited in summer-fall were followed-up in winter. At both visits, a structured clinical interview (DSM-5 criteria) and the Beck Depression Inventory II (BDI-II) were administered. Unesterified and total oxylipin pools were assayed by liquid chromatography tandem mass-spectrometry (LC-MS/MS). Precursor fatty acids were measured by gas chromatography. In nine unmedicated participants euthymic at baseline who met depression criteria in winter, BDI-II scores increased from 4.9±4.4 to 19.9±7.7. Four sEH-derived oxylipins increased in winter compared to summer-fall with moderate to large effect sizes. An auto-oxidation product (unesterified epoxyketooctadecadienoic acid) and lipoxygenase-derived 13-hydroxyoctadecadienoic acid also increased in winter. The cytochrome p450-derived 20-COOH-leukotriene B4 (unesterified) and total 14(15)-epoxyeicosatetraenoic acid, and the sEH-derived 14,15-dihydroxyeicostrienoic acid (unesterified), decreased in winter. We conclude that winter depression was associated with changes in cytochrome p450- and sEH-derived oxylipins, suggesting that seasonal shifts in omega-6 and omega-3 fatty acid metabolism mediated by sEH may underlie inflammatory states in symptomatic MDD-s. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  19. YCl3-Catalyzed Highly Selective Ring Opening of Epoxides by Amines at Room Temperature and under Solvent-Free Conditions

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    Wuttichai Natongchai

    2017-11-01

    Full Text Available A simple, efficient, and environmentally benign approach for the synthesis of β-amino alcohols is herein described. YCl3 efficiently carried out the ring opening of epoxides by amines to produce β-amino alcohols under solvent-free conditions at room temperature. This catalytic approach is very effective, with several aromatic and aliphatic oxiranes and amines. A mere 1 mol % concentration of YCl3 is enough to deliver β-amino alcohols in good to excellent yields with high regioselectivity.

  20. CO2 Conversion: The Potential of Porous–Organic Polymers (POPs) for the cycloaddition of CO2 and epoxides

    KAUST Repository

    Alkordi, Mohamed Helmi

    2016-03-30

    Novel porous organic polymers (POPs) have been synthesized using functionalized Cr and Co-salen complexes as molecular building blocks. The integration of metalosalen catalysts into the porous polymers backbone permits the successful utilization of the materials as solid-state catalysts for CO2-epoxide cycloadditions reactions with excellent catalytic performance under mild conditions of temperature and pressure. The catalyst proved to be fully recyclable and robust thus showing the potential of POPs as smart functional materials for the heterogenization of key catalytic elements.