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Sample records for aliphatic dicarboxylic acid

  1. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  2. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  3. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  4. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  5. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses... salt (PMN P-92-1352) is subject to reporting under this section for the significant new uses...

  6. Effect of aliphatic, monocarboxylic, dicarboxylic, heterocyclic and sulphur-containing amino acids on Leishmania spp. chemotaxis.

    PubMed

    Diaz, E; Zacarias, A K; Pérez, S; Vanegas, O; Köhidai, L; Padrón-Nieves, M; Ponte-Sucre, A

    2015-11-01

    In the sand-fly mid gut, Leishmania promastigotes are exposed to acute changes in nutrients, e.g. amino acids (AAs). These metabolites are the main energy sources for the parasite, crucial for its differentiation and motility. We analysed the migratory behaviour and morphological changes produced by aliphatic, monocarboxylic, dicarboxylic, heterocyclic and sulphur-containing AAs in Leishmania amazonensis and Leishmania braziliensis and demonstrated that L-methionine (10-12 m), L-tryptophan (10-11 m), L-glutamine and L-glutamic acid (10-6 m), induced positive chemotactic responses, while L-alanine (10-7 m), L-methionine (10-11 and 10-7 m), L-tryptophan (10-11 m), L-glutamine (10-12 m) and L-glutamic acid (10-9 m) induced negative chemotactic responses. L-proline and L-cysteine did not change the migratory potential of Leishmania. The flagellum length of L. braziliensis, but not of L. amazonensis, decreased when incubated in hyperosmotic conditions. However, chemo-repellent concentrations of L-alanine (Hypo-/hyper-osmotic conditions) and L-glutamic acid (hypo-osmotic conditions) decreased L. braziliensis flagellum length and L-methionine (10-11 m, hypo-/hyper-osmotic conditions) decreased L. amazonensis flagellum length. This chemotactic responsiveness suggests that Leishmania discriminate between slight concentration differences of small and structurally closely related molecules and indicates that besides their metabolic effects, AAs play key roles linked to sensory mechanisms that might determine the parasite's behaviour.

  7. Properties of Copolymers of Aspartic Acid and Aliphatic Dicarboxylic Acids Prepared by Reactive Extrusion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspartic acid may be prepared chemically or by the fermentation of carbohydrates. Currently, low molecular weight polyaspartic acids are prepared commercially by heating aspartic acid at high temperatures (greater than 220 degrees C) for several hours in the solid state. In an effort to develop a ...

  8. Enzymatic Polymerization of Furan-2,5-Dicarboxylic Acid-Based Furanic-Aliphatic Polyamides as Sustainable Alternatives to Polyphthalamides.

    PubMed

    Jiang, Yi; Maniar, Dina; Woortman, Albert J J; Alberda van Ekenstein, Gert O R; Loos, Katja

    2015-11-01

    Furan-2,5-dicarboxylic acid (FDCA)-based furanic-aliphatic polyamides can be used as promising sustainable alternatives to polyphthalamides (semiaromatic polyamides) and be applied as high performance materials with great commercial interest. In this study, poly(octamethylene furanamide) (PA8F), an analog to poly(octamethylene terephthalamide) (PA8T), is successfully produced via Novozym 435 (N435)-catalyzed polymerization, using a one-stage method in toluene and a temperature-varied two-stage method in diphenyl ether, respectively. The enzymatic polymerization results in PA8F with high weight-average molecular weight (M̅(w)) up to 54000 g/mol. Studies on the one-stage enzymatic polymerization in toluene indicate that the molecular weights of PA8F increase significantly with the concentration of N435; with an optimal reaction temperature of 90 °C. The temperature-varied, two-stage enzymatic polymerization in diphenyl ether yields PA8F with higher molecular weights, as compared to the one-stage procedure, at higher reaction temperatures. MALDI-ToF MS analysis suggests that eight end groups are present in the obtained PA8F: ester/amine, ester/ester, amine/amine, acid/amine, ester/acid, acid/acid, ester/amide, and no end groups (cyclic). Compared to PA8T, the obtained PA8F possesses a similar Tg and similar crystal structures, a comparable Td, but a lower Tm.

  9. Mixed ligand complexes of Cu(II)-2-(2-pyridyl)-benzimidazole and aliphatic or aromatic dicarboxylic acids: Synthesis, characterization and biological activity

    NASA Astrophysics Data System (ADS)

    El-Sherif, Ahmed A.; Jeragh, Bakir J. A.

    2007-11-01

    The synthesis and structural characterization of mixed ligand complexes derived from 2-(2-pyridyl)-benzimidazole (PBI) (1ry ligand) and aliphatic or aromatic dicarboxylic acids (2ry ligand) are reported. Cu(II) complexes were characterized on the bases of their elemental analyses, IR, ESR and thermal analyses. The elemental analysis indicated the formation of mixed ligand complexes in a mole ratio 1:1:1 (Cu:L 1:L 2), L 1 = PBI and L 2 = oxalic acid, phthalic acid or malonic acid. IR spectra showed that PBI acts as a neutral bidentate coordinated to the Cu(II) via the pyridyl and imidazolyl nitrogen atoms. The dicarboxylic acids are bidentate with monodentate carboxylate groups. Thermal decomposition study of complexes was monitored by thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis in N 2 atmosphere. The decomposition course and steps were analysed and the activation parameters of the nonisothermal decomposition were calculated from the TG curves and discussed. The isolated metal chelates were screened for their antimicrobial activities and the results are reported, discussed and compared with some known antibiotics.

  10. Self-assembly in solvates of 2,4-diamino-6-(4-methyl- phenyl)-1,3,5-triazine and in its molecular adducts with some aliphatic dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Nandy, Purnendu; Nayak, Amrita; Biswas, Sharmita Nandy; Pedireddi, V. R.

    2016-03-01

    Solid state structures of 2,4-diamino-6-(4-methylphenyl)-1,3,5-triazine, 1, in the form of methanol and dimethylsulfoxide (DMSO) solvates, as well as supramolecular assemblies of 1 with various aliphatic dicarboxylic acids, oxalic (a), malonic (b), succinic (c), glutaric (d) and adipic (e) have been reported. Analysis of the assemblies has been carried out by single crystal X-ray diffraction and thermal methods. Triazine 1 yields anhydrous molecular adducts with acids a-d, upon co-crystallization either from CH3OH and DMSO solvents. However acid e gives anhydrous adduct from DMSO solvent, while it gives a methanol adduct from CH3OH. Structure determination reveals that molecular adducts 1a, 1d and 1e are in a 2:1 ratio of 1 and the corresponding acid. However the ratio is 1:1, in 1b, perhaps due to the involvement of one of the acid groups in the intramolecular hydrogen bonding and in adduct 1c the ratio observed is 3:2. Structural features in all these assemblies have been rationalised in terms of various recognition patterns formed between the acceptor and donor groups. A noteworthy feature is that -COOH groups in acid a establish interaction with 1 through amino groups, while such interactions are observed to be through hetero -N atoms in case of the acids b-e.

  11. One- and two-dimensional divalent copper coordination polymers based on kinked organodiimine and long flexible aliphatic dicarboxylate ligands

    NASA Astrophysics Data System (ADS)

    Mallika Krishnan, Subhashree; Supkowski, Ronald M.; LaDuca, Robert L.

    2008-11-01

    Hydrothermal synthesis under acidic conditions has afforded a pair of divalent copper coordination polymers containing the kinked dipodal tethering organodiimine 4,4'-dipyridylamine (dpa) and flexible long-chain aliphatic dicarboxylate ligands. The new materials were characterized by single crystal X-ray structure determination, infrared spectroscopy, and thermogravimetric analysis. [CuCl(suberate) 0.5(dpa)] ( 1) manifests 1-D ladder-like motifs aggregated into 3-D through hydrogen bonding and copper-mediated supramolecular interactions. Extension of the aliphatic chain within the dicarboxylate ligand by one methylene unit resulted in {[Cu(azelate)(dpa)(H 2O)] · 3H 2O} ( 2), a (4,4) rhomboid grid 2-D coordination polymer encapsulating acyclic water molecule trimers.

  12. Divergent layer topologies in divalent metal aliphatic dicarboxylate coordination polymers containing 3-pyridylmethylnicotinamide

    NASA Astrophysics Data System (ADS)

    White, Charmaine L.; Torres Salgado, Maria D.; Mizzi, Jessica E.; LaDuca, Robert L.

    2015-12-01

    Hydrothermal reaction of the requisite metal salt, an aliphatic dicarboxylic acid, and the hydrogen-bonding capable dipyridylamide ligand 3-pyridylmethylnicotinamide (3-pmna) resulted in four coordination polymers whose connectedness and layer topology depend on the metal coordination environment and dicarboxylate binding mode. These new crystalline phases were characterized by single crystal X-ray diffraction. [Cu(ox)(3-pmna)]n (1, ox = oxalate) manifests stacked 3-connected (6,3) herringbone layer motifs. {[Cd(mal)(3-pmna)(H2O)]·3H2O}n (2, mal = malonate) shows a 4-connected (4,4) grid topology with entrained water molecule trimeric chains in the interlamellar regions. {[Cd2(suc)2(3-pmna)(H2O)2]·3H2O}n (3, suc = succinate) possesses {Cd2O2} dimer-based [Cd(suc)]n layers pillared by 3-pmna ligands into a 5-connected sandwich motif with 4862 topology. {[Cd(glu)(3-pmna)(H2O)]·3H2O}n (4, glu = glutarate) manifests a rippled (4,4) grid topology. Luminescent behavior in the cadmium complexes is ascribed to intra-ligand molecular orbital transitions. Thermal decomposition behavior is also discussed herein.

  13. Producing dicarboxylic acids using polyketide synthases

    SciTech Connect

    Katz, Leonard; Fortman, Jeffrey L; Keasling, Jay D

    2013-10-29

    The present invention provides for a polyketide synthase (PKS) capable of synthesizing a dicarboxylic acid (diacid). Such diacids include diketide-diacids and triketide-diacids. The invention includes recombinant nucleic acid encoding the PKS, and host cells comprising the PKS. The invention also includes methods for producing the diacids.

  14. Producing dicarboxylic acids using polyketide synthases

    SciTech Connect

    Katz, Leonard; Fortman, Jeffrey L.; Keasling, Jay D.

    2015-05-26

    The present invention provides for a polyketide synthase (PKS) capable of synthesizing a dicarboxylic acid (diacid). Such diacids include diketide-diacids and triketide-diacids. The invention includes recombinant nucleic acid encoding the PKS, and host cells comprising the PKS. The invention also includes methods for producing the diacids.

  15. Combinatorics of aliphatic amino acids.

    PubMed

    Grützmann, Konrad; Böcker, Sebastian; Schuster, Stefan

    2011-01-01

    This study combines biology and mathematics, showing that a relatively simple question from molecular biology can lead to complicated mathematics. The question is how to calculate the number of theoretically possible aliphatic amino acids as a function of the number of carbon atoms in the side chain. The presented calculation is based on earlier results from theoretical chemistry concerning alkyl compounds. Mathematical properties of this number series are highlighted. We discuss which of the theoretically possible structures really occur in living organisms, such as leucine and isoleucine with a chain length of four. This is done both for a strict definition of aliphatic amino acids only involving carbon and hydrogen atoms in their side chain and for a less strict definition allowing sulphur, nitrogen and oxygen atoms. While the main focus is on proteinogenic amino acids, we also give several examples of non-proteinogenic aliphatic amino acids, playing a role, for instance, in signalling. The results are in agreement with a general phenomenon found in biology: Usually, only a small number of molecules are chosen as building blocks to assemble an inconceivable number of different macromolecules as proteins. Thus, natural biological complexity arises from the multifarious combination of building blocks.

  16. Different aliphatic dicarboxylates affected assemble of new coordination polymers constructed from flexible-rigid mixed ligands

    SciTech Connect

    Xu Xinxin; Ma Ying; Wang Enbo

    2007-11-15

    In this article, seven coordination polymers: [Cd(C{sub 5}H{sub 6}O{sub 4})(C{sub 10}H{sub 8}N{sub 2})]{sub n} (1), [Zn(C{sub 5}H{sub 6}O{sub 4})(C{sub 10}H{sub 8}N{sub 2})]{sub n} (2), [Cd(C{sub 6}H{sub 8}O{sub 4})(C{sub 10}H{sub 8}N{sub 2})]{sub n} (3), {l_brace}[Mn(C{sub 10}H{sub 8}N{sub 2})(H{sub 2}O){sub 4}] (C{sub 4}H{sub 4}O{sub 4}).4H{sub 2}O{r_brace}{sub n} (4), [Mn{sub 5}(C{sub 4}H{sub 4}O{sub 4}){sub 4}(O)]{sub n} (5), [Cd(C{sub 4}H{sub 4}O{sub 4})(C{sub 10}H{sub 8}N{sub 2})(H{sub 2}O)]{sub n} (6) and [Zn(C{sub 6}H{sub 6}O{sub 4})(C{sub 12}H{sub 8}N{sub 2})(H{sub 2}O)]{sub n} (7) were synthesized and characterized by single-crystallographic X-ray diffraction. Compounds 1 and 2 are two-dimensional layers connected by glutarate anions and 4,4'-bpy. Unlike compounds 1 and 2, compound 3 is a two-fold interpenetration network. Compound 4 is a one-dimensional chain-like structure, which is further extended to two-dimensional supramolecular layer structure with hydrogen bond. During the synthesis of compound 4, to our surprise, we got compound 5; compound 5 is an interesting three-dimensional network composed of pentanuclear Mn(II) building units and succinate anions. Compound 6 is also a two-dimensional supramolecular layer structure composed of one-dimensional chain-like structure with hydrogen bonds and {pi}-{pi} interactions. Compound 7 is also a one-dimensional chain-like structure, which is further connected with the same kind of interaction to generate two-dimensional supramolecular layer structure. Furthermore, compounds 1 and 2 both exhibit fluorescent property at room temperature. - Graphical abstract: Seven complexes composed by 3D metal ions, aliphatic acid ligand and rigid bidentate nitrogen ligands: 4,4'-bpy, 2,2'-bpy and 1,10'-phen. With the change of the carbon number of the backbone of aliphatic dicarboxylate ligand, we can synthesize different complexes with various structures.

  17. 40 CFR 721.3000 - Dicarboxylic acid monoester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Dicarboxylic acid monoester. 721.3000... Substances § 721.3000 Dicarboxylic acid monoester. (a) Chemical substance and significant new uses subject to... paragraph (a)(2) of this section: dicarboxylic acid monoester, P-83-255. (2) The significant new uses...

  18. 40 CFR 721.3000 - Dicarboxylic acid monoester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Dicarboxylic acid monoester. 721.3000... Substances § 721.3000 Dicarboxylic acid monoester. (a) Chemical substance and significant new uses subject to... paragraph (a)(2) of this section: dicarboxylic acid monoester, P-83-255. (2) The significant new uses...

  19. DICARBOXYLIC ACID CONCENTRATION TRENDS AND SAMPLING ARTIFACTS

    EPA Science Inventory

    Dicarboxylic acids associated with airborne particulate matter were measured during a summer period in Philadelphia that included multiple air pollution episodes. Samples were collected for two ten hour periods each day using a high volume sampler with two quartz fiber filters in...

  20. Yearly trend of dicarboxylic acids in organic aerosols from south of Sweden and source attribution

    NASA Astrophysics Data System (ADS)

    Hyder, Murtaza; Genberg, Johan; Sandahl, Margareta; Swietlicki, Erik; Jönsson, Jan Åke

    2012-09-01

    Seven aliphatic dicarboxylic acids (C3-C9) along with phthalic acid, pinic acid and pinonic acid were determined in 35 aerosol (PM10) samples collected over the year at Vavihill sampling station in south of Sweden. Mixture of dichloromethane and methanol (ratio 1:3) was preferred over water for extraction of samples and extraction was assisted by ultrasonic agitation. Analytes were derivatized using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) containing 1% trimethylsilyl chloride and analyzed using gas chromatography/mass spectrometry. Among studied analytes, azelaic acid was found maximum with an average concentration of 6.0 ± 3.6 ng m-3 and minimum concentration was found for pimelic acid (1.06 ± 0.63 ng m-3). A correlation coefficients analysis was used for defining the possible sources of analytes. Higher dicarboxylic acids (C7-C9) showed a strong correlation with each other (correlation coefficients (r) range, 0.96-0.97). Pinic and pinonic acids showed an increase in concentration during summer. Lower carbon number dicarboxylic acids (C3-C6) and phthalic acid were found strongly correlated, but showed a poor correlation with higher carbon number dicarboxylic acids (C7-C9), suggesting a different source for them. Biomass burning, vehicle exhaust, photo-oxidation of volatile organic compounds (natural and anthropogenic emissions) were possible sources for dicarboxylic acids.

  1. Infrared Predissociation Spectroscopy of H_2-TAGGED Dicarboxylic Acid Anions

    NASA Astrophysics Data System (ADS)

    Wolk, Arron B.; Kamrath, Michael Z.; Leavitt, Christopher M.; Johnson, Mark A.

    2011-06-01

    Singly charged dicarboxylic acid anions, studied in depth by Wang et al. offer insight into the role of ring strain and conformation on the formation of intramolecular hydrogen bonds. These shared proton bonds, common in proteins and polymer systems, can be crucial in secondary and tertiary structure formation. By tracking the infrared spectra of dicarboxylic acid anions as charge and aliphatic chain length are varied, the tendency of these anions to form ring-like structures with an internally shared proton can be asssesed. To adapt the time-of-flight mass spectrometry/infrared presdissociation experiment to larger systems with significant latent vibrational energy and negligible vapor pressure, an electrospray ionization (ESI)/cryogenic quadrupole trap ion source has been interfaced to the Yale time of flight mass spectrometer. Infrared predissociation spectroscopy is carried out on a series of carboxylate anions cooled to 10K and H_2-tagged in a cryogenic ion trap, underscoring the power of this technique to vibrationally quench and structurally characterize large (> 20 atoms) gaseous ions. This technique recovers sharp transitions (~6 cm^-^1 FWHM) in the linear single photon absorption regime which greatly facilitates comparison with ab initio calculations. The methodology used to condense H_2 on these ions is described, revealing the benefits of a pulsed trapping gas paired with a time delay before ion extraction. The sensitivity of the perturbed H_2 transition to charge center exposure is probed by varying the charge and aliphatic chain length of carboxylate anions. Finally, the structure of four carboxylate anions are characterized using their predissociation spectra. H. K. Woo, X. B. Wang, K. C. Lau and L. S. Wang J. Chem. Phys. A 110, 7801-7805 2006.

  2. Aqueous infrared carboxylate absorbances: Aliphatic di-acids

    USGS Publications Warehouse

    Cabaniss, S.E.; Leenheer, J.A.; McVey, I.F.

    1998-01-01

    Aqueous attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra of 18 aliphatic di-carboxylic acids are reported as a function of pH. The spectra show isosbestic points and intensity changes which indicate that Beer's law is obeyed, and peak frequencies lie within previously reported ranges for aqueous carboxylates and pure carboxylic acids. Intensity sharing from the symmetric carboxylate stretch is evident in many cases, so that bands which are nominally due to alkyl groups show increased intensity at higher pH. The asymmetric stretch of the HA- species is linearly related to the microscopic acidity constant of the H2A species, with ??pK 2 intervening atoms). The results suggest that aqueous ATR-FTIR may be able to estimate 'intrinsic' pKa values of carboxylic acids, in addition to providing quantitative estimates of ionization. ?? 1998 Elsevier Science B.V. All rights reserved.

  3. Dehydration polycondensation of dicarboxylic acids and diols using sublimating strong brønsted acids.

    PubMed

    Moyori, Takaya; Tang, Tang; Takasu, Akinori

    2012-05-14

    We investigated catalytic activities of strong brønsted acids for dehydration polycondensations of dicarboxylic acids and diols, which were carried out at low temperature (<100 °C) under reduced pressure (0.3-3 mmHg). Strong Brønsted acids, bis(perfluoroalkanesulfonyl)imide and perfluoroalkanesulfonic acid, showed higher activity than p-toluenesulfonic acid or rare-earth catalysts at 60 °C. In particular, bis(nonafluorobutanesulfonyl)imide (Nf(2)NH) showed the highest activity to synthesize not only aliphatic polyester (M(n) > 19000) but also aromatic polyester (M(n) > 7000). The used Nf(2)NH was sublimated from the reaction flask during polycondensation, and the sublimate, Nf(2)NH, was extra pure so that we can reuse the catalyst without loss of the activity in the dehydration polycondensations.

  4. Selective conversion of biorefinery lignin into dicarboxylic acids.

    PubMed

    Ma, Ruoshui; Guo, Mond; Zhang, Xiao

    2014-02-01

    The emerging biomass-to-biofuel conversion industry has created an urgent need for identifying new applications for biorefinery lignin. This paper demonstrates a new route to producing dicarboxylic acids from biorefinery lignin through chalcopyrite-catalyzed oxidation in a highly selective process. Up to 95 % selectivity towards stable dicarboxylic acids was obtained for several types of biorefinery lignin and model compounds under mild, environmentally friendly reaction conditions. The findings from this study paved a new avenue to biorefinery lignin conversions and applications.

  5. Selective Conversion of Biorefinery Lignin into Dicarboxylic Acids

    SciTech Connect

    Ma, Ruoshui; Guo, Mond; Zhang, Xiao

    2014-02-01

    The emerging biomass-to-biofuel conversion industry has created an urgent need for identifying new applications for biorefinery lignin. This paper demonstrates a new route to producing dicarboxylic acids from biorefinery lignin through chalcopyrite-catalyzed oxidation in a highly selective process. Up to 95 % selectivity towards stable dicarboxylic acids was obtained for several types of biorefinery lignin and model compounds under mild, environmentally friendly reaction conditions. The findings from this study paved a new avenue to biorefinery lignin conversions and applications.

  6. Isoquercitrin Esters with Mono- or Dicarboxylic Acids: Enzymatic Preparation and Properties

    PubMed Central

    Vavříková, Eva; Langschwager, Fanny; Jezova-Kalachova, Lubica; Křenková, Alena; Mikulová, Barbora; Kuzma, Marek; Křen, Vladimír; Valentová, Kateřina

    2016-01-01

    A series of isoquercitrin (quercetin-3-O-β-d-glucopyranoside) esters with mono- or dicarboxylic acids was designed to modulate hydro- and lipophilicity and biological properties. Esterification of isoquercitrin was accomplished by direct chemoenzymatic reaction using Novozym 435 (lipase from Candida antarctica), which accepted C5- to C12-dicarboxylic acids; the shorter ones, such as oxalic (C2), malonic (C3), succinic (C4) and maleic (C4) acids were not substrates of the lipase. Lipophilicity of monocarboxylic acid derivatives, measured as log P, increased with the chain length. Esters with glutaric and adipic acids exhibited hydrophilicity, and the dodecanedioic acid hemiester was more lipophilic. All derivatives were less able to reduce Folin–Ciocalteau reagent (FCR) and scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) than isoquercitrin; ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) radical-scavenging activity was comparable. Dodecanoate and palmitate were the least active in FCR and ABTS scavenging; dodecanoate and hemiglutarate were the strongest DPPH scavengers. In contrast, most derivatives were much better inhibitors of microsomal lipoperoxidation than isoquercitrin; butyrate and hexanoate were the most efficient. Anti-lipoperoxidant activity of monocarboxylic derivatives, except acetates, decreased with increasing aliphatic chain. The opposite trend was noted for dicarboxylic acid hemiesters, isoquercitrin hemidodecanedioate being the most active. Overall, IQ butyrate, hexanoate and hemidodecanedioate are the most promising candidates for further studies. PMID:27338349

  7. Isoquercitrin Esters with Mono- or Dicarboxylic Acids: Enzymatic Preparation and Properties.

    PubMed

    Vavříková, Eva; Langschwager, Fanny; Jezova-Kalachova, Lubica; Křenková, Alena; Mikulová, Barbora; Kuzma, Marek; Křen, Vladimír; Valentová, Kateřina

    2016-01-01

    A series of isoquercitrin (quercetin-3-O-β-d-glucopyranoside) esters with mono- or dicarboxylic acids was designed to modulate hydro- and lipophilicity and biological properties. Esterification of isoquercitrin was accomplished by direct chemoenzymatic reaction using Novozym 435 (lipase from Candida antarctica), which accepted C₅- to C12-dicarboxylic acids; the shorter ones, such as oxalic (C₂), malonic (C₃), succinic (C₄) and maleic (C₄) acids were not substrates of the lipase. Lipophilicity of monocarboxylic acid derivatives, measured as log P, increased with the chain length. Esters with glutaric and adipic acids exhibited hydrophilicity, and the dodecanedioic acid hemiester was more lipophilic. All derivatives were less able to reduce Folin-Ciocalteau reagent (FCR) and scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) than isoquercitrin; ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) radical-scavenging activity was comparable. Dodecanoate and palmitate were the least active in FCR and ABTS scavenging; dodecanoate and hemiglutarate were the strongest DPPH scavengers. In contrast, most derivatives were much better inhibitors of microsomal lipoperoxidation than isoquercitrin; butyrate and hexanoate were the most efficient. Anti-lipoperoxidant activity of monocarboxylic derivatives, except acetates, decreased with increasing aliphatic chain. The opposite trend was noted for dicarboxylic acid hemiesters, isoquercitrin hemidodecanedioate being the most active. Overall, IQ butyrate, hexanoate and hemidodecanedioate are the most promising candidates for further studies. PMID:27338349

  8. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  9. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  10. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  11. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  12. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  13. Study on Dicarboxylic Acids in Aerosol Samples with Capillary Electrophoresis

    PubMed Central

    Adler, Heidi; Sirén, Heli

    2014-01-01

    The research was performed to study the simultaneous detection of a homologous series of α, ω-dicarboxylic acids (C2–C10), oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, with capillary electrophoresis using indirect UV detection. Good separation efficiency in 2,6-pyridinedicarboxylic acid as background electrolyte modified with myristyl trimethyl ammonium bromide was obtained. The dicarboxylic acids were ionised and separated within five minutes. For the study, authentic samples were collected onto dry cellulose membrane filters of a cascade impactor (12 stages) from outdoor spring aerosols in an urban area. Hot water and ultrasonication extraction methods were used to isolate the acids from membrane filters. Due to the low concentrations of acids in the aerosols, the extracts were concentrated with solid-phase extraction (SPE) before determination. The enrichment of the carboxylic acids was between 86 and 134% with sample pretreatment followed by 100-time increase by preparation of the sample to 50 μL. Inaccuracy was optimised for all the sample processing steps. The aerosols contained dicarboxylic acids C2–C10. Then, mostly they contained C2, C5, and C10. Only one sample contained succinic acid. In the study, the concentrations of the acids in aerosols were lower than 10 ng/m3. PMID:24729915

  14. Uranyl Ion Complexes with Long-Chain Aliphatic α,ω-Dicarboxylates and 3d-Block Metal Counterions.

    PubMed

    Thuéry, Pierre; Harrowfield, Jack

    2016-03-01

    Twelve new complexes were obtained from reaction of uranyl ions with the aliphatic dicarboxylic acids HOOC-(CH2)n-2-COOH (H2Cn; n = 7-10 and 12) under solvo-hydrothermal conditions, in the presence of 3d-block metal ions (Mn(2+), Fe(3+), Co(2+), Ni(2+), and Cu(2+)) and 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen). In contrast to previously reported triple-stranded helicates obtained with C9(2-) and C12(2-), all these complexes crystallize as polymeric one-dimensional (1D) or two-dimensional (2D) species. [Fe(bipy)3][(UO2)2(C7)3]·3H2O (1), [Cu(phen)2]2[(UO2)3(C7)4(H2O)2]·2H2O (2), and [Cu(bipy)2]2[(UO2)2(C9)3] (6), in which the 3d cation was reduced in situ, are 1D ladderlike polymers displaying tetra- or hexanuclear rings, of sufficient width to encompass two counterions in 2 and 6. The three complexes [Co(phen)3][(UO2)3(C8)3(O)]·H2O (3), [Ni(phen)3][(UO2)3(C8)3(O)]·H2O (4) and [Co(phen)3][(UO2)3(C9)3(O)]·H2O (5) contain bis(μ3-oxo)-bridged tetranuclear secondary building units, and they crystallize as deeply furrowed 2D assemblies. Depending on the nature of the counterion, C10(2-) gives [Ni(bipy)3][(UO2)2(C10)3]·2H2O (7), a 2D network displaying elongated decanuclear rings containing the counterions, or [Mn(phen)3][(UO2)2(C10)3]·6H2O (8), [Co(phen)3][(UO2)2(C10)3]·7H2O (9), and [Ni(phen)3][(UO2)2(C10)3]·7H2O (10), which consist of 2D assemblies with honeycomb topology; the hexanuclear rings in 8-10 are chairlike and occupied by one counterion and two uranyl groups from neighboring layers. Two complexes of the ligand with the longest chain, C12(2-), are reported. [UO2(C12)(bipy)] (11) is a neutral 1D species in which bipy chelates the uranyl ion and plays an important role in the packing through π-stacking interactions. Two polymeric units, 1D and 2D, coexist in the complex [Ni(bipy)3][(UO2)2(C12)3][UO2(C12)(H2O)2]·H2O (12); the 2D network has the honeycomb topology, but the hexanuclear rings are markedly convoluted, with local features akin to

  15. Tuning different kinds of entangled metal-organic frameworks by modifying the spacer group of aliphatic dicarboxylate ligands and the reactant ratio.

    PubMed

    Yang, Jin-Xia; Zhai, Ji-Quan; Zhang, Xin; Qin, Ye-Yan; Yao, Yuan-Gen

    2016-01-14

    Taking advantage of the conformational flexibility of the bpp ligand and aliphatic dicarboxylic acids, six interesting entangled coordination polymers, {[Cd(fum)(bpp)(H2O)]·(H2O)}n (), {[Cd(fum)(bpp)2]·(H2O)5}n (), {[Cd2(suc)1.5(bpp)2(NO3)(H2O)2]·6H2O}n (), {[Cd(suc)(bpp)2]·(H2O)1.5}n (), {[Cd2(glu)2(bpp)3]·10H2O}n (), and {Cd(adp)(bpp)(H2O)}n () have been prepared and structurally characterized (bpp = 1,3-bi(4-pyridyl)propane, fum = fumaric, suc = succinate, glu = glutaric, adp = adipic). Compounds and are comprised of undulated 2D 4(4)-sql networks. In the structure of compound , two identical undulated layers are parallelly interpenetrated with each other to give a 2D → 2D interpenetrating framework. For , the dangling arms projected from 2D layers are intercalated into the neighboring sheets, producing a 2D → 3D polythreading framework. Compound shows a rare example of a 2D self-penetrating framework with a (3,4)-connected (4(2)·6(3)·8)(4(2)·6) topology. Compound presents an unusual 2D self-threading network with a novel 4-connected {4(2)·6(3)·8} topology. Compound displays a 3D self-penetrating system based on a 2D → 3D parallel polycatenation array. Compound exhibits an unprecedented 3D self-penetrating structure having both 1D + 1D → 1D polycatenation and 3D + 3D → 3D interpenetration characteristics. A comparison of these six compounds demonstrates that both the different spacer lengths of the aliphatic dicarboxylates and reactant ratios appear to play a significant role in the assembly of entangled frameworks. In addition, thermal stabilities and photoluminescence properties of have been examined in the solid state at room temperature. PMID:26621568

  16. Salt and cocrystals of sildenafil with dicarboxylic acids: solubility and pharmacokinetic advantage of the glutarate salt.

    PubMed

    Sanphui, Palash; Tothadi, Srinu; Ganguly, Somnath; Desiraju, Gautam R

    2013-12-01

    Sildenafil is a drug used to treat erectile dysfunction and pulmonary arterial hypertension. Because of poor aqueous solubility of the drug, the citrate salt, with improved solubility and pharmacokinetics, has been marketed. However, the citrate salt requires an hour to reach its peak plasma concentration. Thus, to improve solubility and bioavailability characteristics, cocrystals and salts of the drug have been prepared by treating aliphatic dicarboxylic acids with sildenafil; the N-methylated piperazine of the drug molecule interacts with the carboxyl group of the acid to form a heterosynthon. Salts are formed with oxalic and fumaric acid; salt monoanions are formed with succinic and glutaric acid. Sildenafil forms cocrystals with longer chain dicarboxylic acids such as adipic, pimelic, suberic, and sebacic acids. Auxiliary stabilization via C-H···O interactions is also present in these cocrystals and salts. Solubility experiments of sildenafil cocrystal/salts were carried out in 0.1N HCl aqueous medium and compared with the solubility of the citrate salt. The glutarate salt and pimelic acid cocrystal dissolve faster than the citrate salt in a two hour dissolution experiment. The glutarate salt exhibits improved solubility (3.2-fold) compared to the citrate salt in water. Solubilities of the binary salts follow an inverse correlation with their melting points, while the solubilities of the cocrystals follow solubilities of the coformer. Pharmacokinetic studies on rats showed that the glutarate salt exhibits doubled plasma AUC values in a single dose within an hour compared to the citrate salt. The high solubility of glutaric acid, in part originating from the strained conformation of the molecule and its high permeability, may be the reason for higher plasma levels of the drug.

  17. Method for the production of dicarboxylic acids

    DOEpatents

    Nghiem, N.P.; Donnelly, M.; Millard, C.S.; Stols, L.

    1999-02-09

    The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of (a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; (b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; (c) controllably releasing oxygen to maintain the aerobic atmosphere; (d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/l up to about 1 g/l; (e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; (f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of {>=}1 g/l; and (g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism. 7 figs.

  18. Method for the production of dicarboxylic acids

    DOEpatents

    Nghiem, Nhuan Phu; Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    1999-01-01

    The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; c) controllably releasing oxygen to maintain the aerobic atmosphere; d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/L up to about 1 g/L; e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of .gtoreq.1 g/L; and g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism.

  19. Process for producing peracids from aliphatic hydroxy carboxylic acids

    DOEpatents

    Chum, H.L.; Palasz, P.D.; Ratcliff, M.A.

    1984-12-20

    A process is described for producing peracids from lactic acid-containing solutions derived from biomass processing systems. It consists of adjusting the pH of the solution to about 8 to 9 and removing alkaline residue fractions therefrom to form a solution comprised substantially of lower aliphatic hydroxy acids. The solution is oxidized to produce volatile lower aliphatic aldehydes. The aldehydes are removed as they are generated and converted to peracids.

  20. Process for producing peracids from aliphatic hydroxy carboxylic acids

    DOEpatents

    Chum, Helena L.; Ratcliff, Matthew A.; Palasz, Peter D.

    1986-01-01

    A process for producing peracids from lactic acid-containing solutions derived from biomass processing systems comprising: adjusting the pH of the solution to about 8-9 and removing alkaline residue fractions therefrom to form a solution comprised substantially of lower aliphatic hydroxy acids; oxidizing the solution to produce volatile lower aliphatic aldehydes; removing said aldehydes as they are generated; and converting said aldehydes to peracids.

  1. Quantitative analysis of glycerol in dicarboxylic acid-rich cutins provides insights into Arabidopsis cutin structure.

    PubMed

    Yang, Weili; Pollard, Mike; Li-Beisson, Yonghua; Ohlrogge, John

    2016-10-01

    Cutin is an extracellular lipid polymer that contributes to protective cuticle barrier functions against biotic and abiotic stresses in land plants. Glycerol has been reported as a component of cutin, contributing up to 14% by weight of total released monomers. Previous studies using partial hydrolysis of cuticle-enriched preparations established the presence of oligomers with glycerol-aliphatic ester links. Furthermore, glycerol-3-phosphate 2-O-acyltransferases (sn-2-GPATs) are essential for cutin biosynthesis. However, precise roles of glycerol in cutin assembly and structure remain uncertain. Here, a stable isotope-dilution assay was developed for the quantitative analysis of glycerol by GC/MS of triacetin with simultaneous determination of aliphatic monomers. To provide clues about the role of glycerol in dicarboxylic acid (DCA)-rich cutins, this methodology was applied to compare wild-type (WT) Arabidopsis cutin with a series of mutants that are defective in cutin synthesis. The molar ratio of glycerol to total DCAs in WT cutins was 2:1. Even when allowing for a small additional contribution from hydroxy fatty acids, this is a substantially higher glycerol to aliphatic monomer ratio than previously reported for any cutin. Glycerol content was strongly reduced in both stem and leaf cutin from all Arabidopsis mutants analyzed (gpat4/gpat8, att1-2 and lacs2-3). In addition, the molar reduction of glycerol was proportional to the molar reduction of total DCAs. These results suggest "glycerol-DCA-glycerol" may be the dominant motif in DCA-rich cutins. The ramifications and caveats for this hypothesis are presented. PMID:27211345

  2. trans-cis Configuration regulated supramolecular polymer gels and chirality transfer based on a bolaamphiphilic histidine and dicarboxylic acids.

    PubMed

    Chen, Chunfeng; Wang, Tianyu; Fu, Yunzhi; Liu, Minghua

    2016-01-25

    Supramolecular polymer gels based on the co-assembly of bolaamphiphilic l-histidine(BolaHis) and dicarboxylic acids are dependent on the molar ratios, flexibility and cis-trans configuration of acid molecules. Thus, oligomerized rigid cis-maleic acid or flexible trans-cyclohexane dicarboxylic acid can form chiral supramolecular polymer gels with l-BolaHis. PMID:26617194

  3. Dicarboxylic acids generated by thermal alteration of kerogen and humic acids

    NASA Technical Reports Server (NTRS)

    Kawamura, Kimitaka; Kaplan, I. R.

    1987-01-01

    Significant amounts (up to 2 percent of organic geopolymers) of low-molecular-weight (LMW) dicarboxylic acids (C2-C10) have been detected during thermal alteration (270 C, 2 h) of kerogens and humic acids isolated from young or ancient lithified sediments. Their distribution is characterized by the predominance of oxalic acid followed by succinic, fumaric, and methylsuccinic acids. These acids are probably released by the breakdown of macromolecular structures, which have incorporated biogenic organic compounds, including diacids, during early digenesis in sediments. Because of their reactivity, LMW diacids may play geochemically important roles under natural conditions.

  4. Preparation of polyaniline nanostructures doped with different dicarboxylic acids through template-free method

    NASA Astrophysics Data System (ADS)

    Sun, Chuanyu; Wang, Yu

    2014-09-01

    In this article nanoscaled polyanilines (PANI) were prepared based on template-free method in the presence of dicarboxylic acid dopants (e.g. D-tartaric acid, succinic acid, maleic acid and fumaric acid). The trans-cis isomerization of butenedioic acid played an important role in the formation of nanostructures from the plane-like to nanofibers, and the PANI doped with maleic acid (MA) had larger diameter, higher crystallinity and conductivity than PANI doped with fumaric acid (FA).

  5. Crystal growth and physical characterization of picolinic acid cocrystallized with dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Somphon, Weenawan; Haller, Kenneth J.

    2013-01-01

    Pharmaceutical cocrystals are multicomponent materials containing an active pharmaceutical ingredient with another component in well-defined stoichiometry within the same unit cell. Such cocrystals are important in drug design, particularly for improving physicochemical properties such as solubility, bioavailability, or chemical stability. Picolinic acid is an endogenous metabolite of tryptophan and is widely used for neuroprotective, immunological, and anti-proliferative effects within the body. In this paper we present cocrystallization experiments of a series of dicarboxylic acids, oxalic acid, succinic acid, DL-tartaric acid, pimelic acid, and phthalic acid, with picolinic acid. Characterization by FT-IR and Raman spectroscopy, DSC and TG/DTG analysis, and X-ray powder diffraction show that new compounds are formed, including a 1:1 picolinium tartrate monohydrate, a 2:1 monohydrate adduct of picolinic acid and oxalic acid, and a 2:1 picolinic acid-succinic acid monohydrate cocrystal.

  6. Determination of dicarboxylic acids in tropospherical particles and cloudwater

    NASA Astrophysics Data System (ADS)

    v. Pinxteren, D.; Brüggemann, E.; Herrmann, H.

    2003-04-01

    During two FEBUKO (field investigations of budgets and conversions of particle phase organics in troposheric cloud processes) field campaigns aerosol particle and cloudwater samples were taken in a forestal region in Germany (Thüringer Wald). Particle collection took place in fall 2001 and 2002 at two valley sites (luff and lee) of the mountain Schmücke. On top of this mountain cloudwater was sampled. The aim was to collect and physically and chemically characterize air masses before, while and after passing an orographic cloud in order to provide information about possible multiphase interactions and chemical processing of the aerosol. In this campaign capillary electrophoresis (CE) has been used to determine the dicarboxylic acids. CE has some important advantages for the analysis of ions in aerosol particles compared to the commonly used ion chromatography or gas chromatography. The absolute detection limits are very low (below 1 pmole) and it has a large range of signal-to-concentration linearity. Thus it suits to difficult matrices with strongly changing concentrations and compositions such as aerosol samples. The separation efficiency is usually much higher than in liquid chromatography and the required sample amount is low (down to <1 µL). For sampling of the particles a five-stage low-pressure cascade impactor was used. A humidity-controlled tube bundle served as the inlet device. Tedlar foil was used as an impaction substrate then used for ion analysis. For cloudwater sampling four cloudwater collectors from the California Institute of Technology (CASCC2) were used, which collect droplets with a 50% cut off diameter of 3,5 µm by inertial impaction on several rows of teflon strands. Upcoming results of the measurements are presented.

  7. Performance of AA5052 alloy anode in alkaline ethylene glycol electrolyte with dicarboxylic acids additives for aluminium-air batteries

    NASA Astrophysics Data System (ADS)

    Wang, DaPeng; Zhang, DaQuan; Lee, KangYong; Gao, LiXin

    2015-11-01

    Dicarboxylic acid compounds, i.e. succinic acid (SUA), adipic acid (ADA) and sebacic acid (SEA), are used as electrolyte additives in the alkaline ethylene glycol solution for AA5052 aluminium-air batteries. It shows that the addition of dicarboxylic acids lowers the hydrogen gas evolution rate of commercial AA5052 aluminium alloy anode. AA5052 aluminium alloy has wide potential window for electrochemical activity and better discharge performance in alkaline ethylene glycol solution containing dicarboxylic acid additives. ADA has the best inhibition effect for the self-corrosion of AA5052 anode among the three dicarboxylic acid additives. Fourier transform infrared spectroscopy (FT-IR) reveals that dicarboxylic acids and aluminium ions can form coordination complexes. Quantum chemical calculations shows that ADA has a smaller energy gap (ΔE, the energy difference between the lowest unoccupied orbital and the highest occupied orbital), indicating that ADA has the strongest interaction with aluminium ions.

  8. Decarboxylative Fluorination of Aliphatic Carboxylic Acids via Photoredox Catalysis

    PubMed Central

    Ventre, Sandrine; Petronijevic, Filip R.; MacMillan, David W. C.

    2016-01-01

    The direct conversion of aliphatic carboxylic acids to the corresponding alkyl fluorides has been achieved via visible light-promoted photoredox catalysis. This operationally simple, redox-neutral fluorination method is amenable to a wide variety of carboxylic acids. Photon-induced oxidation of carboxylates leads to the formation of carboxyl radicals, which upon rapid CO2-extrusion and F• transfer from a fluorinating reagent yield the desired fluoroalkanes with high efficiency. Experimental evidence indicates that an oxidative quenching pathway is operable in this broadly applicable fluorination protocol. PMID:25881929

  9. Synthesis of Long Chain Unsaturated-alpha,omega-Dicarboxylic Acids from Renewable Materials via Olefin Metathesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The self-metathesis reaction of soy, rapeseed, tall, and linseed oil fatty acids was investigated for the synthesis of symmetrical long-chain unsaturated-alpha,omega-dicarboxylic acids. The metathesis reactions were carried out in the presence of a Grubbs catalyst under solvent-free conditions at a...

  10. Isolation, characterization, and systematic significance of 2-pyrone-4,6-dicarboxylic acid in Rosaceae.

    PubMed

    Wilkes, S; Glasl, H

    2001-10-01

    2-Pyrone-4,6-dicarboxylic acid was isolated from Potentilla anserina. Until now this substance was only found in bacteria and not in higher plants. By sterile cultivation it was verified that this compound is genuine also in plants. In addition the systematic relevance of 2-pyrone-4,6-dicarboxylic acid within the Rosaceae was tested. The compound seems to be a chemotaxonomic marker for the Rosoideae sensu stricto proposed by Morgan et al. (Morgan, D.R., Soltis, D.E., Robertson, K.R., 1994. Systematic and evolutionary implications of rbcL sequence variation in Rosaceae. American Journal of Botany 81, 890-903).

  11. Polarized Raman spectra and intensities of aliphatic amino acids

    NASA Astrophysics Data System (ADS)

    Himmler, Hans J.; Eysel, Hans H.

    1989-01-01

    Raman spectra of aliphatic α- L-amino acids, glycine, alanine, and valine were re-investigated both in aqueous solution and deuterium oxide solution. The spectra were taken of the zwitterionic and of the completely deprotonated form of the amino acids. Spectra of leucine and isoleucine were studied in water at the isoelectric point. Spectra were recorded both with parallel and perpendicular polarization and the isotropic and anisotropic scattering components were isolated. The integrated intensities of CH stretch, CC stretch and carboxylate bend vibrations are discussed. Linear relations between the number of CC and CH bonds and the total scattered intensity in the appropriate spectral regions are observed. The sum over the carboxylate modes shows characteristic intensities for the first three members of the aliphatic amino acids. An increase of isotropic scattering of ϱ co 2 near 510 cm -1 with increasing chain length of the amino acid (or with increasing concentration) is interpreted as the result of micelle formation.

  12. Synthesis and structural characterisation of amides from picolinic acid and pyridine-2,6-dicarboxylic acid

    PubMed Central

    Devi, Prarthana; Barry, Sarah M.; Houlihan, Kate M.; Murphy, Michael J.; Turner, Peter; Jensen, Paul; Rutledge, Peter J.

    2015-01-01

    Coupling picolinic acid (pyridine-2-carboxylic acid) and pyridine-2,6-dicarboxylic acid with N-alkylanilines affords a range of mono- and bis-amides in good to moderate yields. These amides are of interest for potential applications in catalysis, coordination chemistry and molecular devices. The reaction of picolinic acid with thionyl chloride to generate the acid chloride in situ leads not only to the N-alkyl-N-phenylpicolinamides as expected but also the corresponding 4-chloro-N-alkyl-N-phenylpicolinamides in the one pot. The two products are readily separated by column chromatography. Chlorinated products are not observed from the corresponding reactions of pyridine-2,6-dicarboxylic acid. X-Ray crystal structures for six of these compounds are described. These structures reveal a general preference for cis amide geometry in which the aromatic groups (N-phenyl and pyridyl) are cis to each other and the pyridine nitrogen anti to the carbonyl oxygen. Variable temperature 1H NMR experiments provide a window on amide bond isomerisation in solution. PMID:25954918

  13. Dicarboxylic acids with limited numbers of hydrocarbons stabilize cell membrane and increase osmotic resistance in rat erythrocytes.

    PubMed

    Mineo, Hitoshi; Amita, Nozomi; Kawawake, Megumi; Higuchi, Ayaka

    2013-11-01

    We examined the effect of dicarboxylic acids having 0 to 6 hydrocarbons and their corresponding monocarboxylic or tricarboxylic acids in changing the osmotic fragility (OF) in rat red blood cells (RBCs). Malonic, succinic, glutaric and adipic acids, which are dicarboxylic acids with 1, 2, 3 and 4 straight hydrocarbons located between two carboxylic groups, decreased the OF in a concentration-dependent manner. Other long-chain dicarboxylic acids did not change the OF in rat RBCs. The benzoic acid derivatives, isophthalic and terephthalic acids, but not phthalic acid, decreased the OF in a concentration-dependent manner. Benzene-1,2,3-tricarboxylic acid, but not benzene-1,3,5-tricarboxylic acid, also decreased the OF in rat RBCs. On the other hand, monocarboxylic acids possessing 2 to 7 straight hydrocarbons and benzoic acid increased the OF in rat RBCs. In short-chain dicarboxylic acids, a limited number of hydrocarbons between the two carboxylic groups are thought to form a V- or U-shaped structure and interact with phospholipids in the RBC membrane. In benzene dicarboxylic and tricarboxylic acids, a part of benzene nucleus between the two carboxylic groups is thought to enter the plasma membrane and act on acyl-chain in phospholipids in the RBC membrane. For dicarboxylic and tricarboxylic acids, limited numbers of hydrocarbons in molecules are speculated to enter the RBC membrane with the hydrophilic carboxylic groups remaining outside, stabilizing the structure of the cell membrane and resulting in an increase in osmotic resistance in rat RBCs.

  14. Complexation of Am(III) and Nd(III) by 1,10-Phenanthroline-2,9-Dicarboxylic Acid

    SciTech Connect

    Ogden, Mark D.; Sinkov, Sergey I.; Nilsson, Mikael; Lumetta, Gregg J.; Hancock, Robert D.; Nash, Ken L.

    2013-01-01

    The complexant 1,10-phenanthroline-2,9-dicarboxylic acid (PDA) is a planar tetradentate ligand that is more preorganized for metal complexation than its unconstrained analogue ethylendiiminodiacetic acid (EDDA). Furthermore, the backbone nitrogen atoms of PDA are aromatic, hence are softer than the aliphatic amines of EDDA. It has been hypothesized that PDA will selectively bond to trivalent actinides over lanthanides. In this report, the results of spectrophotometric studies of the complexation of Nd(III) and Am(III) by PDA are reported. Because the complexes are moderately stable, it was necessary to conduct these titrations using competitive equilibrium methods, competitive cation omplexing between PDA and diethylenetriaminepentaacetic acid, and competition between ligand protonation and complex formation. Stability constants and ligand protonation constants were determined at 0.1 mol/L ionic strength and at 0.5 mol/L ionic strength nitrate media at 21 ± 1 C. The stability constants are lower than those predicted from first principles and speciation calculations indicate that Am(III) selectivity over Nd(III) is less than that exhibited by 1,10-phenanthroline.

  15. Defluoridation of water using dicarboxylic acids mediated chitosan-polyaniline/zirconium biopolymeric complex.

    PubMed

    Muthu Prabhu, Subbaiah; Meenakshi, Sankaran

    2016-04-01

    The present investigation describes the preparation of hydrogen bonded chitosan-polyaniline/zirconium biopolymeric matrix by grafting method under dicarboxylic acid medium for the removal of fluoride, first time. Herein, the dicarboxylic acids, oxalic acid, malonic acid, succinic acid were used as medium. The synthesized complex was characterized by usual analytical techniques like FTIR, XRD, SEM and EDAX analysis. From the batch equilibrium experiments, the maximum defluoridation capacity (DC) was found to be 8.713 mg/g at room temperature with the minimum contact time of 24 min at 100mg of the sorbent dosage. The temperature study results of adsorption kinetics showed the adsorption behavior could be better described by the pseudo-second-order equation than pseudo-first-order kinetic model. The adsorption isotherm was well fitted by the Freundlich equation rather than Langmuir and D-R isotherms. The mechanism of fluoride removal was ligand exchange at neutral pH and electrostatic attraction at acidic pH of the medium. Regeneration studies were carried out to identify the best regenerant which makes the process cost-effective. Conclusions of this work demonstrate the potential applicability of the dicarboxylic acid mediated chitosan-polyaniline/zirconium complex as an effective adsorbent for fluoride removal from water. PMID:26706844

  16. Defluoridation of water using dicarboxylic acids mediated chitosan-polyaniline/zirconium biopolymeric complex.

    PubMed

    Muthu Prabhu, Subbaiah; Meenakshi, Sankaran

    2016-04-01

    The present investigation describes the preparation of hydrogen bonded chitosan-polyaniline/zirconium biopolymeric matrix by grafting method under dicarboxylic acid medium for the removal of fluoride, first time. Herein, the dicarboxylic acids, oxalic acid, malonic acid, succinic acid were used as medium. The synthesized complex was characterized by usual analytical techniques like FTIR, XRD, SEM and EDAX analysis. From the batch equilibrium experiments, the maximum defluoridation capacity (DC) was found to be 8.713 mg/g at room temperature with the minimum contact time of 24 min at 100mg of the sorbent dosage. The temperature study results of adsorption kinetics showed the adsorption behavior could be better described by the pseudo-second-order equation than pseudo-first-order kinetic model. The adsorption isotherm was well fitted by the Freundlich equation rather than Langmuir and D-R isotherms. The mechanism of fluoride removal was ligand exchange at neutral pH and electrostatic attraction at acidic pH of the medium. Regeneration studies were carried out to identify the best regenerant which makes the process cost-effective. Conclusions of this work demonstrate the potential applicability of the dicarboxylic acid mediated chitosan-polyaniline/zirconium complex as an effective adsorbent for fluoride removal from water.

  17. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... salt (generic). 721.2098 Section 721.2098 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

  18. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... salt (generic). 721.2098 Section 721.2098 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

  19. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... salt (generic). 721.2098 Section 721.2098 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

  20. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... salt (generic). 721.2098 Section 721.2098 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

  1. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... salt (generic). 721.2098 Section 721.2098 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

  2. The hygroscopic properties of dicarboxylic and multifunctional acids: measurements and UNIFAC predictions.

    PubMed

    Peng, C; Chan, M N; Chan, C K

    2001-11-15

    The role of water-soluble organic compounds on the hygroscopic properties of atmospheric aerosols has recently been the subject of many studies. In particular, low molecular weight dicarboxylic acids and some multifunctional organic acids have been found or are expected to exist in atmospheric aerosols in urban, semiurban, rural, and remote sites. Unlike for their inorganic counterparts, the hygroscopic properties of organic acids have not been well characterized. In this study, the hygroscopic properties of selected water-soluble dicarboxylic acids (oxalic acid, malonic acid, succinic acid, and glutaric acid) and multifunctional acids (citric acid, DL-malic acid, and L-(+)-tartaric acid) were studied using single droplets levitated in an electrodynamic balance at 25 degrees C. The water activities of bulk samples of dilute solutions were also measured. Solute evaporation was observed in the dicarboxylic acids but not in the multifunctional acids. Oxalic acid, succinic acid, and glutaric acid droplets crystallize upon evaporation of water, but, except for glutaric acid droplets, do not deliquesce even at 90% relative humidity (RH). Mass transfer limitation of the deliquescence process was observed in glutaric acid. Neither crystallization nor deliquescence was observed in malonic acid, citric acid, DL-malic acid, or L-(+)-tartaric acid. Malonic acid and these three hydroxy-carboxylic acids absorb water even at RH much lower than their respective deliquescence RH. The growth factor (Gf), defined as the ratio of the particle diameter at RH = 10% to that at RH = 90%, of oxalic acid and succinic acid was close to unity, indicating no hygroscopicity in this range. The remaining acids (malonic acid, glutaric acid, citric acid, malic acid, and tartaric acid) showed roughly similar hygroscopicity of a Gf of 1.30-1.53, which is similar to that of "more hygroscopic" aerosols in field measurements reported in the literature. A generalized equation for these four acids, Gf

  3. Impact of esters of mono- and dicarboxylic acids on diesel fuel quality

    SciTech Connect

    Serdari, A.; Lois, E.; Stournas, S.

    1999-09-01

    The objective of this work was to assess how esters of mono- and dicarboxylic acids of different structure affect diesel fuel quality, by measuring cetane numbers and cold flow properties of blends of the esters under investigation with gasoil. An increase in either the chain length of the normal alcohol used for the esterification or the chain length of the mono- or dicarboxylic acid involved in the esterification improves the cetane number. Among the fatty acid esters of the same molecular type, those having the carboxylic group close to one end of the molecule have better ignition quality, whereas those having the ester group around the middle of the molecule appear to have better cold flow performance. Oleates combine good ignition quality with adequate cold flow performance, whereas the high oxygen content of some diesters seems to be an extra advantage.

  4. Optical Absorption, Stability and Structure of NpO2+ Complexeswith Dicarboxylic Acids

    SciTech Connect

    Guoxin Tian; Linfeng Rao

    2006-01-04

    Complexation of NpO2+ with oxalic acid (OX),2,2'-oxydiacetic acid (ODA), 2,2'-iminodiacetic acid (IDA) and 2,2'-thiodiacetic acid (TDA), has been studied using spectrophotometry in1 M NaClO4. Both the position and the intensity of the absorption band of NpO2+ at 980 nm are affected by the formation of NpO2+/dicarboxylate complexes, providing useful information on the complexation strength, the coordination mode and the structure of the complexes.

  5. Experimental (FTIR and FT-Raman) and theoretical investigation of some pyridine-dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Laxman Naik, J.; Venkatram Reddy, B.; Prabavathi, N.

    2015-11-01

    The FTIR and FT-Raman spectra of 2,3-pyridine-dicarboxylic acid (23PDA); 2,4-pyridine-dicarboxylic acid (24PDA); and 3,4-pyridine-dicarboxylic acid (34PDA) were recorded in the range 4000-450 cm-1 and 4000-50 cm-1, respectively. The optimized geometries and vibrational frequencies along with intensities were computed using DFT employing B3LYP functional with 6-311++G(d,p) basis set. The rms error between observed and calculated frequencies was 11.76, 12.79 and 9.8 cm-1 for 23PDA, 24PDA and 34PDA, respectively. A 74-parameter modified valence force field was evaluated by solving inverse vibrational problem using Wilson's GF matrix method and 99 experimental frequencies of the three molecules were used to refine the force constants in overlay least-squares technique. The average error between observed and computed frequencies was found to be 9.21 cm-1. PED and eigen vectors calculated in the process were used to make unambiguous vibrational assignments. The values of dipole moment, polarizability and hyperpolarizability were computed to determine the NLO behaviour of these molecules. The HOMO and LUMO energies and thermodynamic parameters were also evaluated.

  6. An easy assembled fluorescent sensor for dicarboxylates and acidic amino acids

    PubMed Central

    Zhou, Xiao-bo; Yip, Yuk-Wang; Lee, Albert W M

    2011-01-01

    Summary Two mesitylene based neutral receptors 1 and 2 bearing two thiourea binding sites were constructed as fluorescent probes for sensing dicarboxylates. Their binding affinities toward dicarboxylates, aspartate and glutamate have been investigated in acetonitrile solution by fluorescence titration experiments. Both fluorescent sensors exhibited some ability to discriminate the antipodal forms of aspartate and glutamate. PMID:21286397

  7. Different geometrical arrangements in carboxylate coordination polymers of flexible dicarboxylic acid

    SciTech Connect

    Deka, Himangshu; Sarma, Rupam; Kumari, Satchi; Khare, Alika; Baruah, Jubaraj B.

    2011-07-15

    Dicarboxylate coordination polymers (1-5) of Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II), respectively, derived from (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid (L{sub 1}H{sub 2}) are synthesized and characterized. Depending on the coordination sites around the metal centers and coordination mode of the ligand, dimensionality of these polymers varies. The dicarboxylates adopt three spatial orientations: in-plane linear coordination, out-of-plane cis coordination and out-of-plane trans coordination mode. Both the cis and trans out-of-plane coordination modes are found to exist only if the ancillary ligand pyridine is coordinated to the metal ion. When the aquoligand coordinates the in-plane linear coordination mode of L{sub 1} predominates. The coordination polymers 4 and 5 show photoluminescence in solution. The dicarboxylate of (5-carboxymethoxy-naphthalen-1-yloxy)-acetic acid (L{sub 2}H{sub 2}) does not form coordination polymer under ambient conditions, but prefers to remain as uncoordinated anion providing hydrophobic confinement to hexa-aquometal(II) cation. Compound 3 crystallizes in P2{sub 1} space group and it shows broadband ultra-violet fluorescence centered at 352.9 nm on focusing 632.8 nm He:Ne laser. - Graphical abstract: Different geometrical arrangements in coordination polymers derived from (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid of metal ions Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II) are presented. The (5-carboxymethoxy-naphthalen-1-yloxy)-acetic acid led to hexa-aquo cadmium(II) dicarboxylate. Highlights: > Structural and spectroscopic characterizations of five dicarboxylate coordination polymers of (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid with different metal ions are presented. > Different geometrical arrangements of coordination polymers stabilized in solid state are described. > Photoluminescence properties of the polymers are shown. > NLO property of a copper coordination polymer is described.

  8. Enhanced crystallization of poly (lactic acid) through reactive aliphatic bisamide

    NASA Astrophysics Data System (ADS)

    Nanthananon, P.; Seadan, M.; Pivsa-Art, S.; Suttiruengwong, S.

    2015-07-01

    The poor crystallization rate of poly (lactic acid) (PLA) is a major drawback in terms of controlling the properties of final products. To overcome this, a nucleating agent is normally applied. In this work, the aliphatic bisamide, N, N'-(1,3-propylene) bis(10-undecenamide) (PBU), having reactive functional groups is used as a crystallization promoter for PLA by adding PBU in various concentration (0.1-0.7 wt%) into PLA together with peroxide via reactive melt blending. The conventional ethylene bis-stearamide(EBS) is used for a comparison. The extruded samples are characterized for gel content and FT-IR spectroscopy. The crystallization behaviour and rate, and spherulites morphology are investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM), respectively. It is found that the addition of PBU into PLA results in the dramatic increase in crystallinity and crystallization rate of PLA compared with neat PLA and PLA added EBS. The crystallinity increases to 24.9-28.3% higher than neat PLA under even cooling rate of 7°C/min. The addition of 0.7 wt% PBU shows the fastest crystallization rate with t1/2 value isothermally crystallized at 130°C of only 6 min. POM images indicate the increase in the nucleation density and very fine spherulitesof PLA added PBU, promoting the fast crystallization.

  9. High abundances of water-soluble dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the mountaintop aerosols over the North China Plain during wheat burning season

    NASA Astrophysics Data System (ADS)

    Kawamura, K.; Tachibana, E.; Okuzawa, K.; Aggarwal, S. G.; Kanaya, Y.; Wang, Z. F.

    2013-08-01

    Aerosol (TSP) samples were collected at the summit of Mount Tai (elevation: 1534 m a.s.l., 36.25° N, 117.10° E) located in the North China Plain using a high-volume air sampler and pre-combusted quartz filters. Sampling was conducted on day/night or 3 h basis in the period from 29 May to 28 June 2006 during the field burning of wheat straw residue and the post-burning season. The filter samples were analyzed for low-molecular-weight dicarboxylic acids, ketoacids and α-dicarbonyls using capillary gas chromatography (GC) and GC-MS employing water extraction and butyl ester derivatization. Molecular distributions of dicarboxylic acids (C2-C11, 220-6070 ng m-3) were characterized by a predominance of oxalic (C2) acid (105-3920 ng m-3) followed by succinic (C4) or malonic (C3) acid. Unsaturated aliphatic diacids, including maleic (M), isomaleic (iM) and fumaric (F) acids, were also detected together with aromatic diacids (phthalic, isophthalic and terephthalic acids). ω-oxocarboxylic acids (C2-C9, 24-610 ng m-3) were detected as the second most abundant compound class with the predominance of glyoxylic acid (11-360 ng m-3), followed by α-ketoacid (pyruvic acid, 3-140 ng m-3) and α-dicarbonyls (glyoxal, 1-230 ng m-3 and methylglyoxal, 2-120 ng m-3). We found that these levels (>6000 ng m-3 for diacids) are several times higher than those reported in Chinese megacities at ground levels. The concentrations of diacids increased from late May to early June, showing a maximum on 7 June, and then significantly decreased during the period 8-11 June, when the wind direction shifted from southerly to northerly. Similar temporal trends were found for ketocarboxylic acids and α-dicarbonyls as well as total carbon (TC) and water-soluble organic carbon (WSOC). The temporal variations of water-soluble organics were interpreted by the direct emission from the field burning of agricultural wastes (wheat straw) in the North China Plain and the subsequent photochemical oxidation of

  10. Biodegradation and metabolic pathway of β-chlorinated aliphatic acid in Bacillus sp. CGMCC no. 4196.

    PubMed

    Lin, Chunjiao; Yang, Lirong; Xu, Gang; Wu, Jianping

    2011-04-01

    In this study, a bacterial Bacillus sp. CGMCC no. 4196 was isolated from mud. This strain exhibited the ability to degrade high concentration of 3-chloropropionate (3-CPA, 120 mM) or 3-chlorobutyrate (30 mM), but not chloroacetate or 2-chloropropionate (2-CPA). The growing cells, resting cells, and cell-free extracts from this bacterium had the capability of 3-CPA degradation. The results indicated that the optimum biocatalyst for 3-CPA biodegradation was the resting cells. The 3-CPA biodegradation pathway was further studied through the metabolites and critical enzymes analysis by HPLC, LC-MS, and colorimetric method. The results demonstrated that the metabolites of 3-CPA were 3-hydroxypropionic acid (3-HP) and malonic acid semialdehyde, and the critical enzymes were 3-CPA dehalogenase and 3-HP dehydroxygenase. Thus, the mechanism of the dehalogenase-catalyzed reaction was inferred as hydrolytic dehalogenation which was coenzyme A-independent and oxygen-independent. Finally, the pathway of β-chlorinated aliphatic acid biodegradation could be concluded as follows: the β-chlorinated acid is first hydrolytically dehalogenated to the β-hydroxyl aliphatic acid, and the hydroxyl aliphatic acid is oxidized to β-carbonyl aliphatic acid by β-hydroxy aliphatic acid dehydroxygenase. It is the first report that 3-HP was produced from 3-CPA by β-chlorinated aliphatic acid dehalogenase.

  11. Dicarboxylic acids with limited numbers of hydrocarbons stabilize cell membrane and increase osmotic resistance in rat erythrocytes.

    PubMed

    Mineo, Hitoshi; Amita, Nozomi; Kawawake, Megumi; Higuchi, Ayaka

    2013-11-01

    We examined the effect of dicarboxylic acids having 0 to 6 hydrocarbons and their corresponding monocarboxylic or tricarboxylic acids in changing the osmotic fragility (OF) in rat red blood cells (RBCs). Malonic, succinic, glutaric and adipic acids, which are dicarboxylic acids with 1, 2, 3 and 4 straight hydrocarbons located between two carboxylic groups, decreased the OF in a concentration-dependent manner. Other long-chain dicarboxylic acids did not change the OF in rat RBCs. The benzoic acid derivatives, isophthalic and terephthalic acids, but not phthalic acid, decreased the OF in a concentration-dependent manner. Benzene-1,2,3-tricarboxylic acid, but not benzene-1,3,5-tricarboxylic acid, also decreased the OF in rat RBCs. On the other hand, monocarboxylic acids possessing 2 to 7 straight hydrocarbons and benzoic acid increased the OF in rat RBCs. In short-chain dicarboxylic acids, a limited number of hydrocarbons between the two carboxylic groups are thought to form a V- or U-shaped structure and interact with phospholipids in the RBC membrane. In benzene dicarboxylic and tricarboxylic acids, a part of benzene nucleus between the two carboxylic groups is thought to enter the plasma membrane and act on acyl-chain in phospholipids in the RBC membrane. For dicarboxylic and tricarboxylic acids, limited numbers of hydrocarbons in molecules are speculated to enter the RBC membrane with the hydrophilic carboxylic groups remaining outside, stabilizing the structure of the cell membrane and resulting in an increase in osmotic resistance in rat RBCs. PMID:23770357

  12. Design, Synthesis, EPR-Studies and Conformational Bias of Novel Spin-Labeled DCC-Analogues for the Highly Regioselective Labeling of Aliphatic and Aromatic Carboxylic Acids.

    PubMed

    Gölz, Jan Philipp; NejatyJahromy, Yaser; Bauer, Mirko; Muhammad, Ashraf; Schnakenburg, Gregor; Grimme, Stefan; Schiemann, Olav; Menche, Dirk

    2016-07-01

    Novel types of spin-labeled N,N'-dicyclohexylcarbodiimides (DCC) are reported that bear a 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) residue on one side and different aromatic and aliphatic cyclohexyl analogues on the other side of the diimide core. These readily available novel reagents add efficiently to aliphatic and aromatic carboxylic acids, forming two possible spin-labeled amide derivatives with different radical distances of the resulting amide. The addition of aromatic DCC analogues proceeds with excellent selectivity, giving amides where the carboxylic acid is exclusively connected to the aromatic residue, while little or no selectivity was observed for the aliphatic congeners. The usefulness of these adducts in structural studies was demonstrated by EPR (electron paramagnetic resonance) measurements of biradical adducts of biphenyl-4,4'-dicarboxylic acids. These analyses also reveal high degrees of conformational bias for aromatic DCC derivatives, which further underlines the powerfulness of these novel reagents. This observation was further corroborated by quantum chemical calculations, giving a detailed understanding of the structural dynamics, while detailed information on the solid state structure of all novel reagents was obtained by X-ray structure analyses.

  13. Design, Synthesis, EPR-Studies and Conformational Bias of Novel Spin-Labeled DCC-Analogues for the Highly Regioselective Labeling of Aliphatic and Aromatic Carboxylic Acids.

    PubMed

    Gölz, Jan Philipp; NejatyJahromy, Yaser; Bauer, Mirko; Muhammad, Ashraf; Schnakenburg, Gregor; Grimme, Stefan; Schiemann, Olav; Menche, Dirk

    2016-07-01

    Novel types of spin-labeled N,N'-dicyclohexylcarbodiimides (DCC) are reported that bear a 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) residue on one side and different aromatic and aliphatic cyclohexyl analogues on the other side of the diimide core. These readily available novel reagents add efficiently to aliphatic and aromatic carboxylic acids, forming two possible spin-labeled amide derivatives with different radical distances of the resulting amide. The addition of aromatic DCC analogues proceeds with excellent selectivity, giving amides where the carboxylic acid is exclusively connected to the aromatic residue, while little or no selectivity was observed for the aliphatic congeners. The usefulness of these adducts in structural studies was demonstrated by EPR (electron paramagnetic resonance) measurements of biradical adducts of biphenyl-4,4'-dicarboxylic acids. These analyses also reveal high degrees of conformational bias for aromatic DCC derivatives, which further underlines the powerfulness of these novel reagents. This observation was further corroborated by quantum chemical calculations, giving a detailed understanding of the structural dynamics, while detailed information on the solid state structure of all novel reagents was obtained by X-ray structure analyses. PMID:27272435

  14. Tuning Interchain Interactions in Two-Dimensional Networks of Mn(III) Schiff-Base Complexes and Dicarboxylic Acids by Varying the Linker.

    PubMed

    Aono, Yoshitaka; Yoshida, Hiroki; Katoh, Keiichi; Breedlove, Brian K; Kagesawa, Koichi; Yamashita, Masahiro

    2015-07-20

    Two-dimensional (2D) coordination polymers consisting of Mn(III) Schiff-base complexes and dicarboxylic acids, [{Mn(salen)}4(L1)](PF6)2·(CH3OH)2 (C4; H2L1 = adipid acid) and [{Mn(salen)}4(L2)](PF6)2·(CH3OH)4 (C4'; H2L2 = E,E-1,3-butadiene-1,4-dicarboxylic acid) (salen(2-) = N,N'-(ethylene)bis(salicylideneiminato), were synthesized by using a one-pot reaction and characterized by using single-crystal X-ray crystallographic analysis. One-dimensional (1D) chains composed of Mn(salen) dimers, [Mn2], bridged by carboxylato ligands (-[Mn2]-OCO--[Mn2]-), were linked by dicarboxylato ligands with n-butyl (-C4H8-) (C4) and butadienyl aliphatic groups (-C4H4-) (C4'). From static magnetic measurements on both C4 and C4', there were ferromagnetic interactions between the Mn(III) ions through the phenoxo oxygen atoms of the salen(2-), and antiferromagnetic interactions between the Mn(III) ions through carboxylato ligands (-OCO-). As a result, weak ferromagnetism occurred because of the zigzag-shaped chain structure of C4 and C4', and magnetic anisotropy for Mn(salen). In the magnetization curves for C4', weak interchain interactions (Jlinker) occurred through the π-conjugated butadienyl linkers in C4', which C4 did not have. In other words, changing from saturated to unsaturated aliphatic groups in the dicarboxylic acid linkers resulted in weak interactions between 1D-magnetic chain moieties. Therefore, in the case of only C4', antiferromagnetic phase transition appeared at 2.3 K. Both coordination polymers exhibited slow relaxation of the magnetizations, which originated from SCM moieties, because C4 and C4' showed magnetic correlations. It is noteworthy that alternating current (ac) susceptibilities for C4' are frequency-dependent around the Néel temperature. From analysis of the ac susceptibilities for C4, α (dispersion coefficient of the relaxation of magnetization) varied linearly with 1/T. This signifies that C4 behaved as an SCM with a single relaxation process. On

  15. High abundances of water-soluble dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the mountain aerosols over the North China Plain during wheat burning season

    NASA Astrophysics Data System (ADS)

    Kawamura, K.; Tachibana, E.; Okuzawa, K.; Aggarwal, S. G.; Kanaya, Y.; Wang, Z. F.

    2013-02-01

    Aerosol (TSP) samples were collected at the summit of Mount Tai (elevation: 1534 m a.s.l., 36.25° N; 117.10° E) located in the North China Plain using a high-volume air sampler and pre-combusted quartz filters. Sampling was conducted on day/night or 3 h basis in the period from 29 May to 28 June 2006 during the field burning of wheat straw residue and the post-burning season. The filter samples were analyzed for low molecular weight dicarboxylic acids, ketoacids and α-dicarbonyls using capillary gas chromatography (GC) and GC-MS employing water extraction and butyl ester derivatization. Dicarboxylic acids (C2-C11, 220-6070 ng m-3) were characterized by a predominance of oxalic (C2) acid (105-3920 ng m-3) followed by succinic (C4) or malonic (C3) acid. Unsaturated aliphatic diacids, including maleic (M), isomaleic (iM) and fumaric (F) acid, were also detected together with aromatic diacids (phthalic, iso-phthalic and tere-phthalic acids). ω-Oxocarboxylic acids (C2-C9, 24-610 ng m-3) were detected as the second most abundant compound class with the predominance of glyoxylic acid (11-360 ng m-3), followed by α-ketoacid (pyruvic acid, 3-140 ng m-3) and α-dicarbonyls (glyoxal, 1-230 ng m-3 and methylglyoxal, 2-120 ng m-3). We found that these levels (> 6000 ng m-3 for diacids) are several times higher than those reported in Chinese megacities at ground levels. The concentrations of diacids increased from late May to early June showing a maximum on 7 June and then significantly decreased during 8-11 June when the wind direction shifted from northeasterly to northerly. Similar temporal trends were found for ketocarboxylic acids and α-dicarbonyls as well as total carbon (TC) and water-soluble organic carbon (WSOC). The temporal variations of water-soluble organics were interpreted by the direct emission from the field burning products of agricultural wastes (wheat straw) in the North China Plain and the subsequent photochemical oxidation of volatile and semi

  16. Latitudinal distributions of atmospheric dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls over the western North Pacific: Sources and formation pathways

    NASA Astrophysics Data System (ADS)

    Bikkina, Srinivas; Kawamura, Kimitaka; Miyazaki, Yuzo

    2015-05-01

    The present study aims to assess the molecular distributions of water-soluble dicarboxylic acids (diacids: C2-C12), oxocarboxylic acids (C2-C9), and α-dicarbonyls (glyoxal and methylglyoxal) in aerosols collected over the western North Pacific (WNP) during a summer cruise (August to September 2008). The measured water-soluble organics show pronounced latitudinal distributions with higher concentrations in the region of 30°N-45°N (average 63 ng m-3) than 10°N-30°N (18 ng m-3). Mass fraction of oxalic acid (C2) in total aliphatic diacids (ΣC2-C12) showed higher values (72 ± 10%) in lower latitude (10°N-30°N) than that (56 ± 16%) in higher latitude (30°N-45°N), suggesting a photochemical production of C2 due to an increased insolation over the tropical WNP. A similar trend was found in other diagnostic ratios such as oxalic to succinic (C2/C4) and oxalic to glyoxylic acid (C2/ωC2), which further corroborate an enhanced photochemical aging over the WNP. In addition, relative abundances of oxalic acid in total diacids showed a marked increase as a function of ambient temperature, supporting their photochemical production. Constantly low concentration ratios of adipic and phthalic acids relative to azelaic acid suggest a small contribution of anthropogenic sources and an importance of oceanic sources during the study period. Significant production of C2 through oxidation of biogenic volatile organic compounds emitted from the sea surface is also noteworthy, as inferred from the strong linear correlations among water-soluble organic carbon, methanesulphonic acid, and oxalic acid. Sea-to-air emission of unsaturated fatty acids also contributes to formation of diacids over the WNP.

  17. B vitamin supplementation reduces excretion of urinary dicarboxylic acids in autistic children.

    PubMed

    Kałużna-Czaplińska, Joanna; Socha, Ewa; Rynkowski, Jacek

    2011-07-01

    Urinary dicarboxylic acids are an important source of information about metabolism and potential problems especially connected with energy production, intestinal dysbiosis, and nutritional individuality in autistic children. A diet rich in vitamins and macroelements is a new idea of intervention in autism. The objective of the present study was to test the hypothesis that vitamin B2, vitamin B6, and magnesium supplementation is effective in reducing the level of dicarboxylic acids in the urine of autistic children. We examined the levels of succinic, adipic, and suberic acids in the urine of autistic children before and after vitamin supplementation. Thirty children with autism received magnesium (daily dose, 200 mg), vitamin B6 (pyridoxine; daily dose, 500 mg), and vitamin B2 (riboflavin; daily dose, 20 mg). The treatment was provided for a period of 3 months. Organic acids were determined using gas chromatography/mass spectrometry. Before supplementation, the levels of succinic, adipic, and suberic acids in the urine of autistic children were 41.47 ± 50.40 μmol/mmol creatinine, 15.61 ± 15.31 μmol/mmol creatinine, 8.02 ± 6.08 μmol/mmol creatinine; and after supplementation, the levels were 9.90 ± 8.26 μmol/mmol creatinine, 2.92 ± 2.41 μmol/mmol creatinine, and 2.57 ± 3.53 μmol/mmol creatinine, respectively. The results suggest that the supplementation reduces the level of dicarboxylic acid in the urine of autistic children.

  18. B vitamin supplementation reduces excretion of urinary dicarboxylic acids in autistic children.

    PubMed

    Kałużna-Czaplińska, Joanna; Socha, Ewa; Rynkowski, Jacek

    2011-07-01

    Urinary dicarboxylic acids are an important source of information about metabolism and potential problems especially connected with energy production, intestinal dysbiosis, and nutritional individuality in autistic children. A diet rich in vitamins and macroelements is a new idea of intervention in autism. The objective of the present study was to test the hypothesis that vitamin B2, vitamin B6, and magnesium supplementation is effective in reducing the level of dicarboxylic acids in the urine of autistic children. We examined the levels of succinic, adipic, and suberic acids in the urine of autistic children before and after vitamin supplementation. Thirty children with autism received magnesium (daily dose, 200 mg), vitamin B6 (pyridoxine; daily dose, 500 mg), and vitamin B2 (riboflavin; daily dose, 20 mg). The treatment was provided for a period of 3 months. Organic acids were determined using gas chromatography/mass spectrometry. Before supplementation, the levels of succinic, adipic, and suberic acids in the urine of autistic children were 41.47 ± 50.40 μmol/mmol creatinine, 15.61 ± 15.31 μmol/mmol creatinine, 8.02 ± 6.08 μmol/mmol creatinine; and after supplementation, the levels were 9.90 ± 8.26 μmol/mmol creatinine, 2.92 ± 2.41 μmol/mmol creatinine, and 2.57 ± 3.53 μmol/mmol creatinine, respectively. The results suggest that the supplementation reduces the level of dicarboxylic acid in the urine of autistic children. PMID:21840465

  19. Aircraft observations of water-soluble dicarboxylic acids in the aerosols over China

    NASA Astrophysics Data System (ADS)

    Zhang, Yan-Lin; Kawamura, Kimitaka; Qing Fu, Ping; Boreddy, Suresh K. R.; Watanabe, Tomomi; Hatakeyama, Shiro; Takami, Akinori; Wang, Wei

    2016-05-01

    Vertical profiles of dicarboxylic acids, related organic compounds and secondary organic aerosol (SOA) tracer compounds in particle phase have not yet been simultaneously explored in East Asia, although there is growing evidence that aqueous-phase oxidation of volatile organic compounds may be responsible for the elevated organic aerosols (OA) in the troposphere. Here, we found consistently good correlation of oxalic acid, the most abundant individual organic compounds in aerosols globally, with its precursors as well as biogenic-derived SOA compounds in Chinese tropospheric aerosols by aircraft measurements. Anthropogenically derived dicarboxylic acids (i.e., C5 and C6 diacids) at high altitudes were 4-20 times higher than those from surface measurements and even occasionally dominant over oxalic acid at altitudes higher than 2 km, which is in contrast to the predominance of oxalic acid previously reported globally including the tropospheric and surface aerosols. This indicates an enhancement of tropospheric SOA formation from anthropogenic precursors. Furthermore, oxalic acid-to-sulfate ratio maximized at altitudes of ˜ 2 km, explaining aqueous-phase SOA production that was supported by good correlations with predicted liquid water content, organic carbon and biogenic SOA tracers. These results demonstrate that elevated oxalic acid and related SOA compounds from both the anthropogenic and biogenic sources may substantially contribute to tropospheric OA burden over polluted regions of China, implying aerosol-associated climate effects and intercontinental transport.

  20. Hygroscopic Behavior of Multicomponent Aerosols Involving NaCl and Dicarboxylic Acids.

    PubMed

    Peng, Chao; Jing, Bo; Guo, Yu-Cong; Zhang, Yun-Hong; Ge, Mao-Fa

    2016-02-25

    Atmospheric aerosols are usually complex mixtures of inorganic and organic compounds. The hygroscopicity of mixed particles is closely related to their chemical composition and interactions between components, which is still poorly understood. In this study, the hygroscopic properties of submicron particles composed of NaCl and dicarboxylic acids including oxalic acid (OA), malonic acid (MA), and succinic acid (SA) with various mass ratios are investigated with a hygroscopicity tandem differential mobility analyzer (HTDMA) system. Both the Zdanovskii-Stokes-Robinson (ZSR) method and extended aerosol inorganics model (E-AIM) are applied to predict the water uptake behaviors of sodium chloride/dicarboxylic acid mixtures. For NaCl/OA mixed particles, the measured growth factors were significantly lower than predictions from the model methods, indicating a change in particle composition caused by chloride depletion. The hygroscopic growth of NaCl/MA particles was well described by E-AIM, and that of NaCl/SA particles was dependent upon mixing ratio. Compared with model predictions, it was determined that water uptake of the NaCl/OA mixture could be enhanced and could be closer to the predictions by addition of levoglucosan or malonic acid, which retained water even at low relative humidity (RH), leading to inhibition of HCl evaporation during dehydration. These results demonstrate that the coexisting hygroscopic species have a strong influence on the phase state of particles, thus affecting chemical interactions between inorganic and organic compounds as well as the overall hygroscopicity of mixed particles. PMID:26820230

  1. Water uptake of internally mixed ammonium sulfate and dicarboxylic acid particles probed by infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Miñambres, Lorena; Méndez, Estíbaliz; Sánchez, María N.; Castaño, Fernando; Basterretxea, Francisco J.

    2013-05-01

    Tropospheric aerosols are usually mixtures of inorganic and organic compounds in variable proportions, and the relative amount of organic fraction can influence the hygroscopic properties of the particles. Infrared spectra of submicrometer internally mixed dry particles of ammonium sulfate (AS) with various dicarboxylic acids (oxalic, malonic, maleic, glutaric and pimelic) have been measured in an aerosol flow tube at several solute mass ratios. The spectra show a notable broadening in the bandwidth of sulfate ion ν3 vibrational band near 1115 cm-1 with respect to pure AS. We attribute these perturbations, that are biggest at AS/organic acid mass ratio near unity, to intermolecular interactions between inorganic ions and organic acid molecules in the internally mixed solids. The water uptake behavior of internally mixed particles has been measured by recording the infrared integrated absorbance of liquid water as a function of relative humidity (RH). The amount of water present in the particles prior to deliquescence correlates partially with the water solubilities of the dicarboxylic acids, and also with the relative magnitudes of intermolecular interactions in the internally mixed dry solids. Phase change of ammonium sulfate in the internally mixed particles with RH has been spectrally monitored, and it is shown that water uptaken before full deliquescence produces structural changes in the particles that are revealed by their vibrational spectra.

  2. Urea-acetylene dicarboxylic acid reaction: A likely pathway for prebiotic uracil formation

    NASA Astrophysics Data System (ADS)

    Subbaraman, A. S.; Kazi, Z. A.; Choughuley, A. S. U.; Chadha, M. S.

    1980-12-01

    A number of routes have been suggested for the prebiotic synthesis of uracil involving the reaction of urea with malic acid, propiolic acid, cyanoacetylene and others. Cyanoacetylene has been detected in the interstellar medium as well as simulated prebiotic experiments. It is therefore plausible that dicyanoacetylene and its hydrolytic product acetylene dicarboxylic acid, (ADCA) may have played a role in chemical evolution. This aspect has been examined in the present work for the synthesis of uracil from ADCA and urea reaction. It was found that when ADCA reacted with urea, uracil was formed only in the presence of phosphoric acid and phosphates. Ammonium phosphates gave higher yields of uracil than other phosphates. In the absence of phosphoric acid or phosphates no uracil formation took place. This type of synthesis could have taken place in prebiotic oceans which contained ammonium phosphates and other salts.

  3. Induction of human choriogonadotropin in HeLa-cell cultures by aliphatic monocarboxylates and inhibitors of deoxyribonucleic acid synthesis

    PubMed Central

    Ghosh, Nimai K.; Rukenstein, Adriana; Cox, Rody P.

    1977-01-01

    The ectopic production of the glycopeptide hormone human placental choriogonadotropin by HeLa65 cells was measured by radioimmunoassay with antiserum against the β-subunit of choriogonadotropin and with the 125I-labelled β-subunit as a tracer antigen. Choriogonadotropin synthesis was markedly (500-fold) stimulated by sodium butyrate. Kinetic studies and the use of an inhibitor of protein synthesis, cycloheximide, indicated that protein synthesis was required for this induction. Investigation of the efficiency of 22 aliphatic short-chain fatty acids and derivatives in causing increased choriogonadotropin synthesis by HeLa cells showed stringent structural requirements. Induction of choriogonadotropin synthesis in HeLa cells was not restricted to butyrate. Other aliphatic acids (propionate, isobutyrate, valerate and hexanoate) were also capable of inducing choriogonadotropin synthesis at 10–50% of the efficiency of butyrate. Hydroxy derivatives of monocarboxylate inducers, related mono- and di-carboxylic acids, alcohols, amines, ketones, esters and sulphoxide were ineffective in increasing choriogonadotropin production by HeLa cells. A saturated C4 straight-chain acid without substituent hydroxyl groups but with a methyl group at one end and a carboxyl moiety at the other appeared to be most efficient in activating choriogonadotropin production. A second clonal line of HeLa cells, HeLa71, showed a higher constitutive synthesis of choriogonadotropin than HeLa65 cells, which was also markedly increased by butyrate. Butyrate and other aliphatic monocarboxylate inducers of choriogonadotropin synthesis inhibited HeLa-cell growth and DNA synthesis. This inhibition of DNA replication may be related to the mechanism of choriogonadotropin synthesis, since two well-characterized anti-neoplastic inhibitors of DNA synthesis, hydroxyurea and 1-β-d-arabinofuranosylcytosine, also stimulated a 300-fold increase in choriogonadotropin synthesis in HeLa cells and were synergistic

  4. Size distributions of nano/micron dicarboxylic acids and inorganic ions in suburban PM episode and non-episodic aerosol

    NASA Astrophysics Data System (ADS)

    Hsieh, Li-Ying; Kuo, Su-Ching; Chen, Chien-Lung; Tsai, Ying I.

    The distribution of nano/micron dicarboxylic acids and inorganic ions in size-segregated suburban aerosol of southern Taiwan was studied for a PM episode and a non-episodic pollution period, revealing for the first time the distribution of these nanoscale particles in suburban aerosols. Inorganic species, especially nitrate, were present in higher concentrations during the PM episode. A combination of gas-to-nuclei conversion of nitrate particles and accumulation of secondary photochemical products originating from traffic-related emissions was likely a crucial cause of the PM episode. Sulfate, ammonium, and oxalic acid were the dominant anion, cation, and dicarboxylic acid, respectively, accounting for a minimum of 49% of the total anion, cation or dicarboxylic acid mass. Peak concentrations of these species occurred at 0.54 μm in the droplet mode during both non-episodic and PM episode periods, indicating an association with cloud-processed particles. On average, sulfate concentration was 16-17 times that of oxalic acid. Oxalic acid was nevertheless the most abundant dicarboxylic acid during both periods, followed by succinic, malonic, maleic, malic and tartaric acid. The mass median aerodynamic diameter (MMAD) of oxalic acid was 0.77 μm with a bi-modal presence at 0.54 μm and 18 nm during non-episodic pollution and an MMAD of 0.67 μm with mono-modal presence at 0.54 μm in PM episode aerosol. The concomitant formation of malonic acid and oxalic acid was attributed to in-cloud processes. During the PM episode in the 5-100 nm nanoscale range, an oxalic acid/sulfate mass ratio of 40.2-82.3% suggested a stronger formation potential for oxalic acid than for sulfate in the nuclei mode. For total cations (TC), total inorganic anions (TIA) and total dicarboxylic acids (TDA), major contributing particles were in the droplet mode, with least in the nuclei mode. The ratio of TDA to TIA in the nuclei mode increased greatly from 8.40% during the non-episodic pollution

  5. Piezoelectric crystal microbalance measurements of enthalpy of sublimation of C2-C9 dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Dirri, F.; Palomba, E.; Longobardo, A.; Zampetti, E.

    2015-07-01

    We present here a novel experimental setup able to measure the enthalpy of sublimation of a given compound by means of Piezoelectric Crystal Microbalances (PCM). This experiment was performed in the TG-Lab facility in IAPS-INAF, dedicated to the development of TGA sensors for space measurements, such as detection of organic and non-organic volatile species and refractory materials in planetary environments. In order to study physical-chemical processes concerning the Volatile Organic Compounds (VOC) present in atmospheric environments, the setup has been tested on Dicarboxylic acids. Acids with low molecular weight are among the components of organic fraction of particulate matter in the atmosphere, coming from different sources (biogenic and anthropogenic). Considering their relative abundance, it is useful to consider Dicarboxylic acid as "markers" to define the biogenic or anthropogenic origin of the aerosol, thus obtaining some information of the emission sources. In this work, a temperature controlled effusion cell was used to sublimate VOC, creating a molecular flux that was collimated onto a cold PCM. The VOC re-condensed onto the PCM quartz crystal allowing the determination of the deposition rate. From the measurements of deposition rates, it was possible to infer the enthalpy of sublimation of Adipic acid, i.e. Δ Hsub: 141.6 ± 0.8 kJ mol-1, Succinic acid, i.e. 113.3 ± 1.3 kJ mol-1, Oxalic acid, i.e. 62.5 ± 3.1 kJ mol-1 and Azelaic acid, i.e. 124.2 ± 1.2 kJ mol-1 (weight average values). The results obtained are in very good agreement with literature within 10 % for the Adipic, Succinic and Oxalic acid.

  6. Phenolic and short-chained aliphatic organic acid constituents of wild oat (Avena fatua L.) seeds.

    PubMed

    Gallagher, R S; Ananth, R; Granger, K; Bradley, B; Anderson, J V; Fuerst, E P

    2010-01-13

    The objective of this research was to identify and quantify the phenolic and short-chained aliphatic organic acids present in the seeds of three wild-type populations of wild oat and compare these results to the chemical composition of seeds from two commonly utilized wild oat isolines (M73 and SH430). Phenolic acids have been shown to serve as germination inhibitors, as well as protection for seeds from biotic and abiotic stress factors in other species, whereas aliphatic organic acids have been linked to germination traits and protection against pathogens. Wild oat populations were grown under a "common garden" environment to remove maternal variation, and the resulting seeds were extracted to remove the readily soluble and chemically bound phenolic and aliphatic organic acid components. Compounds were identified and quantified using gas chromatography-mass spectrometry. Ferulic and p-coumaric acid comprised 99% of the total phenolic acids present in the seeds, of which 91% were contained in the hulls and 98% were in the chemically bound forms. Smaller quantities of OH benzoic and vanillic acid were also detected. Soluble organic acids concentrations were higher in the M73 isoline compared to SH430, suggesting that these chemical constituents could be related to seed dormancy. Malic, succinic, fumaric and azelaic acid were the dominant aliphatic organic acids detected in all seed and chemical fractions.

  7. A theoretical study of hydrated molecular clusters of amines and dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Xu, Wen; Zhang, Renyi

    2013-08-01

    Amines and carboxylic acids have been recognized as important precursor species in atmospheric new particle formation. In this study, the interaction between dimethylamine and succinic acid is investigated using Basin Paving Monte Carlo (BPMC) sampling with the classical force field to obtain low energy conformers of dimethylamine and succinic acid hydrated molecular clusters. Geometry optimization and frequency calculations are further performed on the basis of the BPMC results using density functional theory. At standard temperature and pressure, dimethylamine binds to succinic acid with a bonding energy of 14.2 kcal mol-1, smaller than that of dimethylamine with sulfuric acid (21.1 kcal mol-1). Hydration promotes proton transfer from succinic acid to dimethylamine and consequently increases the interaction strength, while proton transfer from sulfuric acid to dimethylamine occurs without hydration. On the other hand, the reactivity of sulfuric acid with dimethylamine decreases with the degree of hydration of sulfuric acid. The free energies of formation for hydrated clusters consisting of dimethylamine and succinic acid reveal that the interaction between amines and dicarboxylic acids likely exerts a synergetic effect on atmospheric aerosol nucleation by formation of aminium carboxylate ion pairs.

  8. Mass spectral analysis of C3 and C4 aliphatic amino acid derivatives.

    NASA Technical Reports Server (NTRS)

    Lawless, J. G.; Chadha, M. S.

    1971-01-01

    Diagnostic criteria are obtained for the distinction of alpha, beta, gamma, and N-methyl isomers of the C3 and C4 aliphatic amino acids, using mass spectral analysis of the derivatives of these acids. The use of deuterium labeling has helped in the understanding of certain fragmentation pathways.

  9. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  10. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  11. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  12. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  13. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  14. Distribution and occurrence of aliphatic acid anions in deep subsurface waters

    SciTech Connect

    Fisher, J.B.

    1987-09-01

    This study reports 144 new analyses of short-chain aliphatic acid anions (acetate, propionate, butyrate, and valerate) in formation waters from eight localities: Eastern Venezuelan Basin, Denver Basin, Eastern Green River Basin, San Juan Basin, Piceance Basin, Raton Basin, Gulf Coast Basin, and the Western Overthrust. Reservoir temperature does not predict total or relative abundance of aliphatic acid anions, but does predict maximum total concentrations of these species. Maximum concentrations increase to approx. 90/sup 0/C. Above approx. 90/sup 0/C, maximum concentrations decrease. Above approx. 250/sup 0/C, maximum concentrations should not exceed approx. 1 mg/l. The general order of dominance is acetate >> propionate > butyrate > valerate, but for coal-associated waters is propionate greater than or equal to acetate > butyrate > valerate. Lack of longer-chain aliphatic acid anion dominance over acetate at low reservoir temperatures may suggest hydrologic communication with deeper reservoirs.

  15. Short hydrogen bonds in salts of dicarboxylic acids; structural correlations from solid-state 13C and 2H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kalsbeek, Nicoline; Schaumburg, Kjeld; Larsen, Sine

    1993-10-01

    Solid-state 13C and 2H NMR spectra are found to very suitable for characterizing the short Osbnd H...O hydrogen bonds observed in acid salts of dicarboxylic acids. The majority of the investigated compounds are acid salts of malonic, succinic and tartaric acid with monovalent cations derived from alkali metals and small aliphatic amines. They include systems with symmetric and asymmetric hydrogen bonds. Accurate structural information about their geometry is available from low-temperature X-ray diffraction data. The 13C chemical shifts of the C atoms in the different carboxy groups display a linear variation with the absolute difference between the two Csbnd O bond lengths. Theoretical ab initio calculations for model systems showed that the nuclear quadrupole coupling constant NQCC for 2H increases with increasing asymmetry of the hydrogen-bonded system. NQCC values for 2H in the short symmetric hydrogen-bonded systems are in the range 53-59 kHz compared with the larger values of up to 166kHz found in systems with longer asymmetric hydrogen bonds. The 2H NQCC values display a perfect linear dependence on the asymmetry of the hydrogen bond. 2H NQCC decreases with decreasing temperature in the symmetric hydrogen bonds showing that the corresponding potential has a single well.

  16. Sutter's Mill dicarboxylic acids as possible tracers of parent-body alteration processes

    NASA Astrophysics Data System (ADS)

    Pizzarello, Sandra; Garvie, Laurence A. J.

    2014-11-01

    Dicarboxylic acids were searched for in three Sutter's Mill (SM) fragments (SM2 collected prerain, SM12, and SM41) and found to occur almost exclusively as linear species of 3- to 14-carbon long. Between these, concentrations were low, with measured quantities typically less than 10 nmole g-1 of meteorite and a maximum of 6.8 nmole g-1 of meteorite for suberic acid in SM12. The SM acids' molecular distribution is consistent with a nonbiological origin and differs from those of CMs, such as Murchison or Murray, and of some stones of the C2-ungrouped Tagish Lake meteorite, where they are abundant and varied. Powder X-ray diffraction of SM12 and SM41 show them to be dominated by clays/amorphous material, with lesser amounts of Fe-sulfides, magnetite, and calcite. Thermal gravimetric (TG) analysis shows mass losses up to 1000 °C of 11.4% (SM12) and 9.4% (SM41). These losses are low compared with other clay-rich carbonaceous chondrites, such as Murchison (14.5%) and Orgueil (21.1%). The TG data are indicative of partially dehydrated clays, in accordance with published work on SM2, for which mineralogical studies suggest asteroidal heating to around 500 °C. In view of these compositional traits and mineralogical features, it is suggested that the dicarboxylic acids observed in the SM fragments we analyzed likely represent a combination of molecular species original to the meteorite as well as secondary products formed during parent-body alteration processes, such as asteroidal heating.

  17. Silver-Catalyzed Decarboxylative Radical Azidation of Aliphatic Carboxylic Acids in Aqueous Solution.

    PubMed

    Liu, Chao; Wang, Xiaoqing; Li, Zhaodong; Cui, Lei; Li, Chaozhong

    2015-08-12

    We report herein an efficient and general method for the decarboxylative azidation of aliphatic carboxylic acids. Thus, with AgNO3 as the catalyst and K2S2O8 as the oxidant, the reactions of various aliphatic carboxylic acids with tosyl azide or pyridine-3-sulfonyl azide in aqueous CH3CN solution afforded the corresponding alkyl azides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific azidation.

  18. New aliphatic alcohol and (Z)-4-coumaric acid glycosides from Acanthus ilicifolius.

    PubMed

    Wu, Jun; Zhang, Si; Huang, Jianshe; Xiao, Qiang; Li, Qingxin; Long, Lijuan; Huang, Liangmin

    2003-10-01

    From the aerial parts of Acanthus ilicifolius, a new aliphatic alcohol glycoside (ilicifolioside C) and two new (Z)-4-coumaric acid glycosides, (Z)-4-coumaric acid 4-O-beta-D-glucopyranoside and (Z)-4-coumaric acid 4-O-beta-D-apiofuranosyl-(1"-->2')-O-beta-D-glucopyranoside were isolated. The structural elucidations were based on the analyses of spectroscopic data. Z-Form 4-coumaric acid glycosides were first isolated from plant.

  19. Biomimetic Fenton-catalyzed lignin depolymerization to high-value aromatics and dicarboxylic acids.

    PubMed

    Zeng, Jijiao; Yoo, Chang Geun; Wang, Fei; Pan, Xuejun; Vermerris, Wilfred; Tong, Zhaohui

    2015-03-01

    By mimicking natural lignin degradation systems, the Fenton catalyst (Fe(3+), H2O2) can effectively facilitate lignin depolymerization in supercritical ethanol (7 MPa, 250 °C) to give organic oils that consist of mono- and oligomeric aromatics, phenols, dicarboxylic acids, and their derivatives in yields up to (66.0±8.5) %. The thermal properties, functional groups, and surface chemistry of lignin before and after Fenton treatment were examined by thermogravimetric analysis, pyrolysis-gas chromatography-mass spectrometry, (31)P NMR spectroscopy, and X-ray photoelectron spectroscopy. The results suggest that the Fenton catalyst facilitates lignin depolymerization through cleavage of β-ether bonds between lignin residues. The formation of a lignin-iron chelating complex effectively depresses lignin recondensation; thus minimizing charcoal formation and enhancing the yield of liquid products.

  20. Biodegradation of the chelator 2,6-pyridine dicarboxylic acid (PDA) used for soil metal extraction

    SciTech Connect

    Banerji, S.K.; Regmi, T.P.

    1998-12-31

    In this research the biodegradability of 2,6-pyridine dicarboxylic acid (PDA) was evaluated. This compound has been used as a chelating agent for extraction of metal ions from contaminated soils. Initial experiments indicated that PDA was not biodegraded by unacclimated mixed cultures to any degree. However, acclimated mixed cultures degraded more than 80% of this compound within 12 h under different conditions without showing any sign of inhibition even at high concentrations up to 6 mM (1000 mg/l). The results of PDA biodegradation at all concentrations tested in aqueous solution were very similar to those observed in presence of soil slurry, except that a slight lag of microbial growth occurred at all PDA concentrations in the latter case. No toxicity was evident to the microorganisms during the biodegradation of lead complexed PDA after an initial lag. The PDA complexed with lead was easily available for metabolism by the acclimated mixed culture.

  1. Noncovalent-bonded 1D-3D supramolecular architectures from 2-methylquinoline/quinoline with monocarboxylic acid and dicarboxylic acid

    NASA Astrophysics Data System (ADS)

    Gao, Xingjun; Jin, Shouwen; Jin, Li; Ye, XiangHang; Zheng, Lu; Li, JingWen; Jin, BinPeng; Wang, Daqi

    2014-10-01

    Studies concentrating on noncovalent weak interactions between the organic base of 2-methylquinoline/quinoline, and carboxylic acid derivatives have led to an increased understanding of the role 2-methylquinoline/quinoline have in binding with carboxylic acids. Here anhydrous multicomponent organic acid-base adducts of 2-methylquinoline/quinoline have been prepared with carboxylic acids that ranged from monocarboxylic acid to dicarboxylic acid such as p-nitrobenzoic acid, (4-chloro-phenoxy)-acetic acid, 4-hydroxy-benzoic acid, 5-bromosalicylic acid, 2,4-dihydroxybenzoic acid, α-ketoglutaric acid, and 4-nitrophthalic acid. The seven crystalline complexes were characterized by X-ray diffraction analysis, IR, m.p., and elemental analysis. These structures adopted the hetero supramolecular synthons. Analysis of the crystal packing of 1-7 suggests that there are Nsbnd H⋯O, Osbnd H⋯N, and Osbnd H⋯O hydrogen bonds (charge assisted or neutral) between the acid and quinoline moieties in the studied compounds. Except the classical hydrogen bonding interactions, the secondary propagating interactions also play important roles in structure extension. These weak interactions combined, these compounds displayed 1D-3D framework structure.

  2. 40 CFR 721.10289 - Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). 721.10289 Section 721.10289 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New...

  3. 40 CFR 721.10289 - Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). 721.10289 Section 721.10289 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New...

  4. 40 CFR 721.10289 - Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). 721.10289 Section 721.10289 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New...

  5. Versatile and sustainable synthesis of cyclic imides from dicarboxylic acids and amines by Nb2O5 as a base-tolerant heterogeneous Lewis acid catalyst.

    PubMed

    Ali, Md Ayub; Siddiki, S M A Hakim; Kon, Kenichi; Hasegawa, Junya; Shimizu, Ken-Ichi

    2014-10-27

    Catalytic condensation of dicarboxylics acid and amines without excess amount of activating reagents is the most atom-efficient but unprecedented synthetic method of cyclic imides. Here we present the first general catalytic method, proceeding selectively and efficiently in the presence of a commercial Nb2 O5 as a reusable and base-tolerant heterogeneous Lewis acid catalyst. The method is effective for the direct synthesis of pharmaceutically or industrially important cyclic imides, such as phensuximide, N-hydroxyphthalimide (NHPI), and unsubstituted cyclic imides from dicarboxylic acid or anhydrides with amines, hydroxylamine, or ammonia.

  6. Piezoelectric crystal microbalance measurements of enthalpy of sublimation of C2-C9 dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Dirri, F.; Palomba, E.; Longobardo, A.; Zampetti, E.

    2016-02-01

    We present here a novel experimental set-up that is able to measure the enthalpy of sublimation of a given compound by means of piezoelectric crystal microbalances (PCMs). The PCM sensors have already been used for space measurements, such as for the detection of organic and non-organic volatile species and refractory materials in planetary environments. In Earth atmospherics applications, PCMs can be also used to obtain some physical-chemical processes concerning the volatile organic compounds (VOCs) present in atmospheric environments. The experimental set-up has been developed and tested on dicarboxylic acids. In this work, a temperature-controlled effusion cell was used to sublimate VOC, creating a molecular flux that was collimated onto a cold PCM. The VOC recondensed onto the PCM quartz crystal, allowing the determination of the deposition rate. From the measurements of deposition rates, it has been possible to infer the enthalpy of sublimation of adipic acid, i.e. ΔHsub : 141.6 ± 0.8 kJ mol-1, succinic acid, i.e. 113.3 ± 1.3 kJ mol-1, oxalic acid, i.e. 62.5 ± 3.1 kJ mol-1, and azelaic acid, i.e. 124.2 ± 1.2 kJ mol-1. The results obtained show an accuracy of 1 % for succinic, adipic, and azelaic acid and within 5 % for oxalic acid and are in very good agreement with previous works (within 6 % for adipic, succinic, and oxalic acid and within 11 % or larger for azelaic acid).

  7. Synthesis, structure and properties of zinc(II) coordination polymers with 9H-carbazole-2,7-dicarboxylic acid

    NASA Astrophysics Data System (ADS)

    Yi, Xiu-Chun; Xi, Fu-Gui; Wang, Kun; Su, Zhao; Gao, En-Qing

    2013-10-01

    From a new dicarboxylate ligand, 9H-carbazole-2,7-dicarboxylic acid (2,7-H2CDC), three Zn(II) metal-organic frameworks were synthesized in the absence or presence of ditopic N-donor ligands. They are formulated as [Zn5(μ3-OH)2(2,7-CDC)4(DEF)2] (1) (DEF=N,N-diethylformamide), [Zn2(2,7-CDC)2(DABCO)(H2O)]·5DMF·H2O (2) (DABCO=1-diaza-bicyclo[2.2.2]octane, DMF=N,N-dimethylformamide), and [Zn2(2,7-CDC)2(bpea)]·3DMA·2 H2O (3) (bpea=1,2-bis(4-pyridyl)ethylane, DMA=N,N-dimethylacetamide). Compounds 1 and 3 display the 3D pcu frameworks. In 1 the unusual pentanuclear [Zn5(μ3-OH)2(COO)8] secondary building units (SBUs) are linked by dicarboxylate ligands. Differently, in 3 the well-known paddle-wheel [Zn2(COO)4] SBUs are linked by dicarboxylate and dipyridyl ligands. Compound 2 shows the rare self-catenated 3D alb-3,6-C2/c net topology based on the dinuclear paddle-wheel SBU and a mononuclear unit. The stability and fluorescent properties of the compounds have been studied.

  8. Synthesis, structure and properties of zinc(II) coordination polymers with 9H-carbazole-2,7-dicarboxylic acid

    SciTech Connect

    Yi, Xiu-Chun; Xi, Fu-Gui; Wang, Kun; Su, Zhao; Gao, En-Qing

    2013-10-15

    From a new dicarboxylate ligand, 9H-carbazole-2,7-dicarboxylic acid (2,7-H{sub 2}CDC), three Zn(II) metal-organic frameworks were synthesized in the absence or presence of ditopic N-donor ligands. They are formulated as [Zn{sub 5}(μ{sub 3}-OH){sub 2}(2,7-CDC){sub 4}(DEF){sub 2}] (1) (DEF=N,N-diethylformamide), [Zn{sub 2}(2,7-CDC){sub 2}(DABCO)(H{sub 2}O)]·5DMF·H{sub 2}O (2) (DABCO=1-diaza-bicyclo[2.2.2]octane, DMF=N,N-dimethylformamide), and [Zn{sub 2}(2,7-CDC){sub 2}(bpea)]·3DMA·2 H{sub 2}O (3) (bpea=1,2-bis(4-pyridyl)ethylane, DMA=N,N-dimethylacetamide). Compounds 1 and 3 display the 3D pcu frameworks. In 1 the unusual pentanuclear [Zn{sub 5}(μ{sub 3}-OH){sub 2}(COO){sub 8}] secondary building units (SBUs) are linked by dicarboxylate ligands. Differently, in 3 the well-known paddle–wheel [Zn{sub 2}(COO){sub 4}] SBUs are linked by dicarboxylate and dipyridyl ligands. Compound 2 shows the rare self-catenated 3D alb-3,6-C2/c net topology based on the dinuclear paddle–wheel SBU and a mononuclear unit. The stability and fluorescent properties of the compounds have been studied. - Graphical abstract: A new dicarboxylate ligand, 9H-carbazole-2,7-dicarboxylic acid, was used to construct Zn(II) metal-organic frameworks, including a novel self-catenated network with the rare 3D alb-3,6-C2/c net and two pcu-type networks based on an unprecedented pentanuclear clusters and the common paddle–wheel units. The compounds show blue fluorescent properties. Display Omitted - Highlights: • MOFs with a new carbazole-based dicarboxylate ligand. • New pentanuclear [Zn{sub 5}(μ{sub 3}-OH){sub 2}(COO){sub 8}] secondary building unit. • The rare self-catenated 3D alb-3,6-C2/c net.

  9. Charge transport through dicarboxylic-acid-terminated alkanes bound to graphene-gold nanogap electrodes

    NASA Astrophysics Data System (ADS)

    Liu, Longlong; Zhang, Qian; Tao, Shuhui; Zhao, Cezhou; Almutib, Eman; Al-Galiby, Qusiy; Bailey, Steven W. D.; Grace, Iain; Lambert, Colin J.; Du, Jun; Yang, Li

    2016-07-01

    Graphene-based electrodes are attractive for single-molecule electronics due to their high stability and conductivity and reduced screening compared with metals. In this paper, we use the STM-based matrix isolation I(s) method to measure the performance of graphene in single-molecule junctions with one graphene electrode and one gold electrode. By measuring the length dependence of the electrical conductance of dicarboxylic-acid-terminated alkanes, we find that the transport is consistent with phase-coherent tunneling, but with an attenuation factor of βN = 0.69 per methyl unit, which is lower than the value measured for Au-molecule-Au junctions. Comparison with density-functional-theory calculations of electron transport through graphene-molecule-Au junctions and Au-molecule-Au junctions reveals that this difference is due to the difference in Fermi energies of the two types of junction, relative to the frontier orbitals of the molecules. For most molecules, their electrical conductance in graphene-molecule-Au junctions is higher than that in Au-molecule-Au junctions, which suggests that graphene offers superior electrode performance, when utilizing carboxylic acid anchor groups.Graphene-based electrodes are attractive for single-molecule electronics due to their high stability and conductivity and reduced screening compared with metals. In this paper, we use the STM-based matrix isolation I(s) method to measure the performance of graphene in single-molecule junctions with one graphene electrode and one gold electrode. By measuring the length dependence of the electrical conductance of dicarboxylic-acid-terminated alkanes, we find that the transport is consistent with phase-coherent tunneling, but with an attenuation factor of βN = 0.69 per methyl unit, which is lower than the value measured for Au-molecule-Au junctions. Comparison with density-functional-theory calculations of electron transport through graphene-molecule-Au junctions and Au

  10. Spatial separation of individual substances in effloresced crystals of ternary ammonium sulphate/dicarboxylic acid/water aerosols.

    PubMed

    Treuel, Lennart; Sandmann, Alice; Zellner, Reinhard

    2011-04-18

    This work examines the crystals resulting from the efflorescence of internally mixed aqueous aerosols comprising ammonium sulphate and different dicarboxylic acids. Most studies on the deliquescence of aerosols use previously effloresced aerosols in their experiments. However, during efflorescence a highly supersaturated solution crystallises in a kinetically controlled way unlike the case of thermodynamically controlled crystallisation. Herein the distribution of individual substances within the effloresced crystals is investigated using Raman scanning experiments. The data presented show an intriguingly complex behaviour of these ternary and quarternary aerosols. A spatial separation of substances in the crystals resulting from the efflorescence of previously internally mixed ternary salt/dicarboxylic acid/water aerosol droplets is demonstrated and mechanistic aspects are discussed. PMID:21472958

  11. Aliphatic, Cyclic, and Aromatic Organic Acids, Vitamins, and Carbohydrates in Soil: A Review

    PubMed Central

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-01-01

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research. PMID:24319374

  12. Aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil: a review.

    PubMed

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-11-10

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research.

  13. Aliphatic structure of humic acids; a clue to their origin

    USGS Publications Warehouse

    Hatcher, P.G.; Maciel, G.E.; Dennis, L.W.

    1981-01-01

    Nuclear magnetic resonance spectra (both 1H and 13C) of humic acids from diverse depositional environments indicate the presence of aromatic chemical structures, most likely derived from lignin of vascular plants, and complex, paraffinic structures, most likely derived from algal or microbial sources. The latter components account for a major fraction of humic acid structures in both terrestrial and aquatic environments, suggesting that algae or microbes play a large role in humification of organic remains from both systems. ?? 1981.

  14. Temperature dependences of saturated vapor pressure and the enthalpy of vaporization of n-pentyl esters of dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Portnova, S. V.; Krasnykh, E. L.; Levanova, S. V.

    2016-05-01

    The saturated vapor pressures and enthalpies of vaporization of n-pentyl esters of linear C2-C6 dicarboxylic acids are determined by the transpiration method in the temperature range of 309.2-361.2 K. The dependences of enthalpies of vaporization on the number of carbon atoms in the molecule and on the retention indices have been determined. The predictive capabilities of the existing calculation schemes for estimation of enthalpy of vaporization of the studied compounds have been analyzed.

  15. Measuring enthalpy of sublimation of volatiles by means of micro-thermogravimetry: the case of Dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Dirri, F.; Longobardo, A.; Palomba, E.; Zampetti, E.; Biondi, D.; Boccaccini, A.; Saggin, B.; Bearzotti, A.; Macagnano, A.

    2013-09-01

    VISTA (Volatile In Situ Thermogravimetry Analyser) is a thermogravimeter currently under study for the proposed mission MarcoPolo-R [1,2]. In the framework of this project, we developed a set-up to measure the enthalpy of sublimation ΔH of three dicarboxylic acids, i.e. adipic, succinic and oxalic. The obtained results are in good agreement with literature, and this demonstrates the capability of our device to perform this kind of measurements.

  16. Synthesis and crystal structure of new lanthanide coordination polymers with Pyridine-2, 6-dicarboxylic acid

    NASA Astrophysics Data System (ADS)

    Du, Rui-Zhi; Wang, Yan-Yan; Xie, Yu-Yu; Li, Hao-Tian; Liu, Tian-Fu

    2016-03-01

    Reactions between Ln(NO3)3 aq (Ln = La (1), Ce (2), Pr (3) and Nd(4)), pyridine-2, 6-dicarboxylic acid (2, 6-pdc), and sodium nitroprusside Na2[Fe(CN)5NO] lead to three-dimensional network structures: {[Ln2(2, 6-pdc)2(H2O)8][Fe(CN)5NO]·4H2O}n (Ln = La (1), Ce (2), Pr (3) and Nd(4)). The complexes 1 and 2 crystallize in the monoclinic space group Cc while complexes 3 and 4 crystallize in the monoclinic space group I2. The Ln(III) ion is nine-coordinate by four oxygen atoms of three 2, 6-pdc ligands, four oxygen of water and one nitrogen atom of 2, 6-pdc. Ln(III) ions are bridged by 2, 6-pdc ligands via bridging/chelating-bridging pentadentate coordination to form 3-D framework structures. Hydrogen bonds provide additional stabilization of the crystal structures. The magnetic properties of 2-4 have been investigated.

  17. Electron ionization and dissociation of aliphatic amino acids

    NASA Astrophysics Data System (ADS)

    Papp, P.; Shchukin, P.; Kočíšek, J.; Matejčík, Š.

    2012-09-01

    We present experimental and theoretical study of electron ionization and dissociative ionization to the gas phase amino acids valine, leucine, and isoleucine. A crossed electron/molecular beams technique equipped with quadrupole mass analyzer has been applied to measure mass spectra and ion efficiency curves for formation of particular ions. From experimental data the ionization energies of the molecules and the appearance energies of the fragment ions were determined. Ab initio calculations (Density Functional Theory and G3MP2 methods) were performed in order to calculate the fragmentation paths and interpret the experimental data. The experimental ionization energies of parent molecules [P]+ 8.91 ± 0.05, 8.85 ± 0.05, and 8.79 ± 0.05 eV and G3MP2 ionization energies (adiabatic) of 8.89, 8.88, and 8.81 eV were determined for valine, leucine, and isoleucine, respectively, as well as the experimental and theoretical threshold energies for dissociative ionization channels. The comparison of experimental data with calculations resulted in identification of the ions as well as the neutral fragments formed in the dissociative reactions. Around 15 mass/charge ratio fragments were identified from the mass spectra by comparison of experimental appearance energies with calculated reaction enthalpies for particular dissociative reactions.

  18. Carboxylic and Dicarboxylic Acids Extracted from Crushed Magnesium Oxide Single Crystals

    NASA Technical Reports Server (NTRS)

    Freund, Friedemann; Gupta, Alka D.; Kumar, Devendra; DeVincenzi, Donald (Technical Monitor)

    1998-01-01

    Carboxylic and dicarboxylic acids (glycolic, oxalic, malonic and succinic) have been extracted with tetrahydrofuran (THE) and H2O from large synthetic MgO crystals, crushed to a medium fine powder. The extracts were characterized by infrared spectroscopy and (sup 1)H-NMR (Nuclear Magnetic Resonance). The THF extracts were derivatized with tert-butyldimethylsilyl (t-BDMS) for GC-MS (Gas Chromatography - Mass Spectroscopy) analysis. A single crystal separated from the extract was used for an x-ray structure analysis, giving the monoclinic unit cell, space group P2(sub 1)/c with a(sub o) = 5.543 A, b(sub o) = 8.845 A, c(sub o) = 5.086 A, and beta = 91.9 degrees, consistent with beta-succinic acid, HOOC(CH2)COOH. The amount of extracted acids is estimated to be of the order of 0.1 to 0.5 mg/g MgO. The MgO crystals from which these organic acids were extracted grew from the 2360 C hot melt, saturated with CO/CO2 and H2O, thereby incorporating small amounts of the gaseous components to form a solid solution (ss) with MgO. Upon cooling, the ss becomes supersaturated, causing solute carbon and other solute species to segregate not only to the surface but also internally, to dislocations and subgrain boundaries. The organic acids extracted from the MgO crystals after crushing appear to derive from these segregated solutes that formed C-C, C-H, and C-O bonds along dislocations and other defects in the MgO structure, leading to entities that can generically be described as (HxCyOz)(sup n-). The processes underlying the formation of these precursors are fundamental in nature and expected to be operational in any minerals, preferentially those with dense structures, that crystallized in H2O-CO2-laden environments. This opens the possibility that common magmatic and metamorphic rocks when weathering at the surface of a tectonically active planet like Earth may be an important source of abiogenically formed complex organic compounds.

  19. Carboxylic and dicarboxylic acids extracted from crushed magnesium oxide single crystals

    NASA Technical Reports Server (NTRS)

    Freund, F.; Gupta, A. D.; Kumar, D.

    1999-01-01

    Carboxylic and dicarboxylic acids (glycolic, oxalic, malonic and succinic) have been extracted with tetrahydrofuran (THF) and H2O from large synthetic MgO crystals, crushed to a medium fine powder. The extracts were characterized by infrared spectroscopy and 1H-NMR. The THF extracts were derivatized with tert-butyldimethylsilyl (t-BDMS) for GC-MS analysis. A single crystal separated from the extract was used for an x-ray structure analysis, giving the monoclinic unit cell, space group P21/c with ao = 5.543 A, bo = 8.845 A, co = 5.086 A, and beta = 91.9 degrees, consistent with beta-succinic acid, HOOC(CH2)COOH. The amount of extracted acids is estimated to be of the order of 0.1 to 0.5 mg g-1 MgO. The MgO crystals from which these organic acids were extracted grew from the 2860 degrees C hot melt, saturated with CO/CO2 and H2O, thereby incorporating small amounts of the gaseous components to form a solid solution (ss) with MgO. Upon cooling, the ss becomes supersaturated, causing solute carbon and other solute species to segregate not only to the surface but also internally, to dislocations and subgrain boundaries. The organic acids extracted from the MgO crystals after crushing appear to derive from these segregated solutes that formed C-C, C-H and C-O bonds along dislocations and other defects in the MgO structure, leading to entities that can generically be described as (HxCyOz)n-. The processes underlying the formation of these precursors are fundamental in nature and expected to be operational in any minerals, preferentially those with dense structures, that crystallized in H2O-CO2-laden environments. This opens the possibility that common magmatic and metamorphic rocks when weathering at the surface of a tectonically active planet like Earth may be an important source of abiogenically formed complex organic compounds.

  20. Method of increasing conversion of a fatty acid to its corresponding dicarboxylic acid

    DOEpatents

    Craft, David L.; Wilson, C. Ron; Eirich, Dudley; Zhang, Yeyan

    2004-09-14

    A nucleic acid sequence including a CYP promoter operably linked to nucleic acid encoding a heterologous protein is provided to increase transcription of the nucleic acid. Expression vectors and host cells containing the nucleic acid sequence are also provided. The methods and compositions described herein are especially useful in the production of polycarboxylic acids by yeast cells.

  1. Effects of the dicarboxylic acids malate and fumarate on E. coli 0157:H7 and Salmonella enterica Typhimurium populations in pure culture and in mixed ruminal microorganism fermentations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dicarboxylic organic acids malate and fumarate increase ruminal pH, reduce methane production, increase propionate and total VFA production, and reduce lactic acid accumulation in a manner similar to ionophores. These acids stimulate the ruminal bacterium Selenomonas ruminantium to ferment lact...

  2. The C4-dicarboxylic acid pathway of photosynthesis. Identification of intermediates and products and quantitative evidence for the route of carbon flow

    PubMed Central

    Johnson, Hilary S.; Hatch, M. D.

    1969-01-01

    1. When leaves with the C4-dicarboxylic acid pathway of photosynthesis are exposed to 14CO2 the major labelled compounds formed, in order of labelling, are dicarboxylic acids, 3-phosphoglycerate, bexose phosphates and sucrose. During the present studies several quantitatively minor intermediates were identified and their labelling behaviour is described. 2. The pattern of labelling of dihydroxyacetone phosphate, fructose 1,6-diphosphate and ribulose di- and mono-phosphates during radiotracer pulse–chase experiments was consistent with their operation as intermediates in the pathway of carbon dioxide fixation. 3. Serine, glycine, alanine and glutamate had labelling patterns typical of products secondary to the main flow of carbon. 4. The mechanism of the transfer of label from C-4 of dicarboxylic acids to C-1 of 3-phosphoglycerate was also examined. Evidence consistent with pyruvate being derived from C-1, C-2 and C-3 of oxaloacetate, and for a relationship between ribulose 1,5-diphosphate and the acceptor for the C-4 carboxyl group, was obtained. 5. Evidence is provided that, under steady-state conditions, essentially all the label incorporated from 14CO2 into C-1 of 3 phosphoglycerate enters via C-4 of the dicarboxylic acids. These and other studies indicated that the route via dicarboxylic acids is essentially the sole route for entry of carbon into 3-phosphoglycerate. PMID:5810044

  3. Synthesis, Properties and Applications of Biodegradable Polymers Derived from Diols and Dicarboxylic Acids: From Polyesters to Poly(ester amide)s

    PubMed Central

    Díaz, Angélica; Katsarava, Ramaz; Puiggalí, Jordi

    2014-01-01

    Poly(alkylene dicarboxylate)s constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and α-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amide)s derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed. PMID:24776758

  4. Aliphatic amidase of Rhodococcus rhodochrous PA-34: Purification, characterization and application in synthesis of acrylic acid.

    PubMed

    Thakur, Neerja; Kumar, Vijay; Sharma, Nirmal Kant; Thakur, Shikha; Bhalla, Tek Chand

    2016-01-01

    An intracellular aliphatic amide degrading inducible amidase produced by Rhodococcus rhodochrous PA-34 was characterized and acrylic acid synthesis from acrylamide was carried out using whole cell amidase. A bioprocess was developed at 50 ml fed batch reaction using 400 mM acrylamide feeding at an interval of 30 min resulted in the production of 4 g acrylic acid with volumetric and catalytic productivity of 80 g/l and 19 g/g/h respectively. The amidase of this organism had molecular weight of 40 kDa and was purified to 8.5 fold with 8% yield. This enzyme was active within the temperature range of 30 to 60 °C, with optimum temperature 45 °C and pH 7.5. The Vmax, Km, and kcat of purified amidase were calculated as 250 U/mg protein, 4.5 mM, and 166 sec-1 for acrylamide. The enzyme showed tolerance to metal chelating agent (EDTA) and was strongly inhibited by heavy metal ions Hg2+, Ag2+, Cu2+ and Co2+. R. rhodochrous PA-34 amidase preferentially hydrolyzed small aliphatic toxic amide such as acrylamide. Thus, the amidase of R. rhodochrous PA-34 is promising biocatalyst for the synthesis of industrially important acids and biodegradation of toxic amides. PMID:26667322

  5. Effect of dicarboxylic acid chain length on the self-cleaning property of Nano-TiO2-coated cotton fabrics.

    PubMed

    Khajavi, Ramin; Berendjchi, Amirhosein

    2014-11-12

    In this study, the effect of dicarboxylic acid chain length on the amount of TiO2 nanoparticles (TiO2NPs) adsorption-produced self-cleaning property and washing durability on cotton fabrics were investigated. First, cotton fabric samples were treated with three kinds of dicarboxylic acids--oxalic, succinic, and adipic acids--and then dipped in TiO2NP solution with a certain concentration. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used to investigate bonds formation between dicarboxylic acid groups and hydroxyl groups of cellulose, and a scanning electron microscope (SEM) was applied for the analysis of surface morphology in specimens. Drop absorbency time was determined for samples using the AATCC TM 79:2000. Washing stability and the amount absorption of TiO2NPs were determined by weighing and absorption spectrophotometry procedures, and the stain removal evaluation was conducted to assess the self-cleaning property. Results showed that all of the dicarboxylic acids used in this experiment improved the amount of TiO2NPs absorbed onto cotton samples and their durability to washing. In addition, color variation of samples treated with oxalic acid after 180 min of UV irradiation and drop absorbency time for samples treated with succinic acid were significantly increased by about 126 and 600%, respectively. The best durability was obtained from adipic acid, while a better self-cleaning property was obtained from oxalic acid.

  6. Effect of dicarboxylic acid chain length on the self-cleaning property of Nano-TiO2-coated cotton fabrics.

    PubMed

    Khajavi, Ramin; Berendjchi, Amirhosein

    2014-11-12

    In this study, the effect of dicarboxylic acid chain length on the amount of TiO2 nanoparticles (TiO2NPs) adsorption-produced self-cleaning property and washing durability on cotton fabrics were investigated. First, cotton fabric samples were treated with three kinds of dicarboxylic acids--oxalic, succinic, and adipic acids--and then dipped in TiO2NP solution with a certain concentration. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used to investigate bonds formation between dicarboxylic acid groups and hydroxyl groups of cellulose, and a scanning electron microscope (SEM) was applied for the analysis of surface morphology in specimens. Drop absorbency time was determined for samples using the AATCC TM 79:2000. Washing stability and the amount absorption of TiO2NPs were determined by weighing and absorption spectrophotometry procedures, and the stain removal evaluation was conducted to assess the self-cleaning property. Results showed that all of the dicarboxylic acids used in this experiment improved the amount of TiO2NPs absorbed onto cotton samples and their durability to washing. In addition, color variation of samples treated with oxalic acid after 180 min of UV irradiation and drop absorbency time for samples treated with succinic acid were significantly increased by about 126 and 600%, respectively. The best durability was obtained from adipic acid, while a better self-cleaning property was obtained from oxalic acid. PMID:25275802

  7. Morphology and phase transformations of tin oxide nanostructures synthesized by the hydrothermal method in the presence of dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Zima, Tatyana.; Bataev, Ivan

    2016-11-01

    A new approach to the synthesis of non-stoichiometric tin oxide structures with different morphologies and the phase compositions has been evaluated. The nanostructures were synthesized by hydrothermal treatment of the mixtures of dicarboxylic acids ― aminoterephthalic or oxalic ― with nanocrystalline SnO2 powder, which was obtained via the sol-gel technology. The products were characterized by Raman and IR spectroscopy, SEM, HRTEM, and XRD analysis. It was shown that the controlled addition of a dicarboxylic acid leads not only to a change in the morphology of the nanostructures, but also to SnO2-SnO2/Sn3O4-Sn3O4-SnO phase transformations. A single-phase Sn3O4 in the form of the well-separated hexagonal nanoplates and mixed SnO2/Sn3O4 phases in the form of hierarchical flower-like structures were obtained in the presence of organic additives. The effects of concentration, redox activity of the acids and heat treatment on the basic characteristics of the synthesized tin oxide nanostructures and phase transformations in the synthesized materials are discussed.

  8. Laboratory photochemical processing of aqueous aerosols: formation and degradation of dicarboxylic acids, oxocarboxylic acids and α-dicarbonyls

    NASA Astrophysics Data System (ADS)

    Pavuluri, C. M.; Kawamura, K.; Mihalopoulos, N.; Swaminathan, T.

    2015-07-01

    To better understand the photochemical processing of dicarboxylic acids and related polar compounds, we conducted batch UV irradiation experiments on two types of aerosol samples collected from India, which represent anthropogenic (AA) and biogenic (BA) aerosols, for time periods of 0.5 to 120 h. The irradiated samples were analyzed for molecular compositions of diacids, oxoacids and α-dicarbonyls. The results show that photochemical degradation of oxalic (C2), malonic (C3) and other C8-C12 diacids overwhelmed their production in aqueous aerosols, whereas succinic acid (C4) and C5-C7 diacids showed a significant increase (ca. 10 times) during the course of irradiation experiments. The photochemical formation of oxoacids and α-dicarbonyls overwhelmed their degradation during the early stages of experiment except for ω-oxooctanoic acid (ωC8), which showed a similar pattern to that of C4. We also found a gradual decrease in the relative abundance of C2 to total diacids and an increase in the relative abundance of C4 during prolonged experiment. Based on the changes in concentrations and mass ratios of selected species with the irradiation time, we hypothesize that iron-catalyzed photolysis of C2 and C3 diacids controls their concentrations in Fe-rich atmospheric waters, whereas photochemical formation of C4 diacid (via ωC8) is enhanced with photochemical processing of aqueous aerosols in the atmosphere. This study demonstrates that the ambient aerosols contain abundant precursors that produce diacids, oxoacids and α-dicarbonyls, although some species such as oxalic acid decompose extensively during an early stage of photochemical processing.

  9. Laboratory photochemical processing of aqueous aerosols: formation and degradation of dicarboxylic acids, oxocarboxylic acids and α-dicarbonyls

    NASA Astrophysics Data System (ADS)

    Pavuluri, C. M.; Kawamura, K.; Mihalopoulos, N.; Swaminathan, T.

    2015-01-01

    To better understand the photochemical processing of dicarboxylic acids and related polar compounds, we conducted batch UV irradiation experiments on two types of aerosol samples collected from India, which represent anthropogenic (AA) and biogenic aerosols (BA), for time periods of 0.5 to 120 h. The irradiated samples were analyzed for molecular compositions of diacids, oxoacids and α-dicarbonyls. The results show that photochemical degradation of oxalic (C2) and malonic (C3) and other C8-C12 diacids overwhelmed their production in aqueous aerosols whereas succinic acid (C4) and C5-C7 diacids showed a significant increase (ca. 10 times) during the course of irradiation experiments. The photochemical formation of oxoacids and α-dicarbonyls overwhelmed their degradation during the early stages of experiment, except for ω-oxooctanoic acid (ωC8) that showed a similar pattern to that of C4. We also found a gradual decrease in the relative abundance of C2 to total diacids and an increase in the relative abundance of C4 during prolonged experiment. Based on the changes in concentrations and mass ratios of selected species with the irradiation time, we hypothesize that iron-catalyzed photolysis of C2 and C3 diacids dominates their concentrations in Fe-rich atmospheric waters, whereas photochemical formation of C4 diacid (via ωC8) is enhanced with photochemical processing of aqueous aerosols in the atmosphere. This study demonstrates that the ambient aerosols contain abundant precursors that produce diacids, oxoacids and α-dicarbonyls, although some species such as oxalic acid decompose extensively during an early stage of photochemical processing.

  10. Resolution of a Challenge for Solvation Modeling: Calculation of Dicarboxylic Acid Dissociation Constants Using Mixed Discrete-Continuum Solvation Models

    SciTech Connect

    Marenich, Aleksandr; Ding, Wendu; Cramer, Christopher J.; Truhlar, Donald G.

    2012-06-07

    First and second dissociation constants (pKa values) of oxalic acid, malonic acid, and adipic acid were computed by using a number of theoretical protocols based on density functional theory and using both continuum solvation models and mixed discrete-continuum solvation models. We show that fully implicit solvation models (in which the entire solvent is represented by a dielectric continuum) fail badly for dicarboxylic acids with mean unsigned errors averaged over six pKa values) of 2.4-9.0 log units, depending on the particular implicit model used. The use of water-solute clusters and accounting for multiple conformations in solution significantly improve the performance of both generalized Born solvation models and models that solve the nonhomogeneous dielectric Poisson equation for bulk electrostatics. The four most successful models have mean unsigned errors of only 0.6-0.8 log units.

  11. A novel approach in cinnamic acid synthesis: direct synthesis of cinnamic acids from aromatic aldehydes and aliphatic carboxylic acids in the presence of boron tribromide.

    PubMed

    Chiriac, Constantin I; Tanasa, Fulga; Onciu, Marioara

    2005-02-28

    Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP) and pyridine (Py) as bases and N-methyl-2-pyrolidinone (NMP) as solvent, at reflux (180-190 degrees C) for 8-12 hours.

  12. Seasonal and longitudinal distributions of atmospheric water-soluble dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls over the North Pacific

    NASA Astrophysics Data System (ADS)

    Bikkina, Srinivas; Kawamura, Kimitaka; Imanishi, Katsuya; Boreddy, S. K. R.; Nojiri, Yukihiro

    2015-05-01

    In order to assess the seasonal variability of atmospheric abundances of dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls over the North Pacific and Sea of Japan, aerosol samples were collected along the longitudinal transacts during six cruises between Canada and Japan. The back trajectory analyses indicate that aerosol samples collected in winter and spring are influenced by the East Asian outflow, whereas summer and fall samples are associated with the pristine maritime air masses. Molecular distributions of water-soluble organics in winter and spring samples show the predominance of oxalic acid (C2) followed by succinic (C4) and malonic acids (C3). In contrast, summer and fall marine aerosols are characterized by the predominance of C3 over C4. Concentrations of dicarboxylic acids were higher over the Sea of Japan than the North Pacific. With a lack of continental outflow, higher concentrations during early summer are ascribed to atmospheric oxidation of organic precursors associated with high biological activity in the North Pacific. This interpretation is further supported by the high abundances of azelaic acid, which is a photochemical oxidation product of biogenic unsaturated fatty acids, over the Bering Sea in early summer when surface waters are characterized by high biological productivity. We found higher ratios of oxalic acid to pyruvic and glyoxylic acids (C2/Pyr and C2/ωC2) and glyoxal and methylglyoxal (C2/Gly and C2/MeGly) in summer and fall than in winter and spring, suggesting a production of C2 from the aqueous-phase oxidation of oceanic isoprene. In this study, dicarboxylic acids account for 0.7-38% of water-soluble organic carbon.

  13. Chiral Sensing of Various Amino Acids Using Induced Circularly Polarized Luminescence from Europium(III) Complexes of Phenanthroline Dicarboxylic Acid Derivatives.

    PubMed

    Uchida, Taka-Aki; Nozaki, Koichi; Iwamura, Munetaka

    2016-09-01

    Circularly polarized luminescence (CPL) was observed from [Eu(dppda)2 ](-) (dppda=4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid) and [Eu(pzpda)2 ](-) (pzpda=pyrazino[2,3-f][1,10]phenanthroline-7,10-dicarboxylic acid) in aqueous solutions containing various amino acids. The selectivity of these complexes towards amino acids enabled them to be used as chiral sensors and their behavior was compared with that of [Eu(pda)2 ](-) (pda=1,10-phenanthroline-2,9-dicarboxylic acid). As these Eu(III) complexes have achiral D2d structures under ordinary conditions, there were no CPL signals in the emission assigned to f-f transitions. However, when the solutions contained particular amino acids they exhibited detectable CPL signals with glum values of about 0.1 (glum =CPL/2 TL; TL=total luminescence). On examining 13 amino acids with these three Eu(III) complexes, it was found that whether an amino acid induced a detectable CPL depended on the Eu(III) complex ligands. For example, when ornithine was used as a chiral agent, only [Eu(dppda)2 ](-) exhibited intense CPL in aqueous solutions of 10(-2)  mol dm(-3) . Steep amino acid concentration dependence suggested that CPL in [Eu(dppda)2 ](-) and [Eu(pzpda)2 ](-) was induced by the association of four or more amino acid molecules, whereas CPL in [Eu(pda)2 ](-) was induced by association of two arginine molecules.

  14. Chiral Sensing of Various Amino Acids Using Induced Circularly Polarized Luminescence from Europium(III) Complexes of Phenanthroline Dicarboxylic Acid Derivatives.

    PubMed

    Uchida, Taka-Aki; Nozaki, Koichi; Iwamura, Munetaka

    2016-09-01

    Circularly polarized luminescence (CPL) was observed from [Eu(dppda)2 ](-) (dppda=4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid) and [Eu(pzpda)2 ](-) (pzpda=pyrazino[2,3-f][1,10]phenanthroline-7,10-dicarboxylic acid) in aqueous solutions containing various amino acids. The selectivity of these complexes towards amino acids enabled them to be used as chiral sensors and their behavior was compared with that of [Eu(pda)2 ](-) (pda=1,10-phenanthroline-2,9-dicarboxylic acid). As these Eu(III) complexes have achiral D2d structures under ordinary conditions, there were no CPL signals in the emission assigned to f-f transitions. However, when the solutions contained particular amino acids they exhibited detectable CPL signals with glum values of about 0.1 (glum =CPL/2 TL; TL=total luminescence). On examining 13 amino acids with these three Eu(III) complexes, it was found that whether an amino acid induced a detectable CPL depended on the Eu(III) complex ligands. For example, when ornithine was used as a chiral agent, only [Eu(dppda)2 ](-) exhibited intense CPL in aqueous solutions of 10(-2)  mol dm(-3) . Steep amino acid concentration dependence suggested that CPL in [Eu(dppda)2 ](-) and [Eu(pzpda)2 ](-) was induced by the association of four or more amino acid molecules, whereas CPL in [Eu(pda)2 ](-) was induced by association of two arginine molecules. PMID:27380553

  15. The development of benzo- and naphtho-fused quinoline-2,4-dicarboxylic acids as vesicular glutamate transporter (VGLUT) inhibitors reveals a possible role for neuroactive steroids.

    PubMed

    Carrigan, Christina N; Patel, Sarjubhai A; Cox, Holly D; Bolstad, Erin S; Gerdes, John M; Smith, Wesley E; Bridges, Richard J; Thompson, Charles M

    2014-02-01

    Substituted quinoline-2,4-dicarboxylates (QDCs) are conformationally-restricted mimics of glutamate that were previously reported to selectively block the glutamate vesicular transporters (VGLUTs). We find that expanding the QDC scaffold to benzoquinoline dicarboxylic acids (BQDC) and naphthoquinoline dicarboxylic acids (NQDCs) improves inhibitory activity with the NQDCs showing IC50∼70 μM. Modeling overlay studies showed that the polycyclic QDCs resembled steroid structures and led to the identification and testing of estrone sulfate, pregnenolone sulfate and pregnanolone sulfate that blocked the uptake of l-Glu by 50%, 70% and 85% of control, respectively. Pregnanolone sulfate was further characterized by kinetic pharmacological determinations that demonstrated competitive inhibition and a Ki of ≈20 μM. PMID:24424130

  16. Recommended Correlations for the Surface Tension of Aliphatic, Carboxylic, and Polyfunctional Organic Acids

    NASA Astrophysics Data System (ADS)

    Mulero, A.; Cachadiña, I.; Sanjuán, E. L.

    2016-09-01

    In previous papers, we have proposed specific correlations to reproduce the surface tension values for several sets of fluids and for wide ranges of temperatures. In this paper, we focus our attention on organic fatty (aliphatic, carboxylic, and polyfunctional) acids. We have taken into account the available data and values in the DIPPR and DETHERM databases and also Wohlfarth and Wohlfarth's (1997) book. In some cases we have also considered new data published elsewhere. All the data and values have been carefully filtered and subsequently fitted with the use of the model currently implemented in NIST's REFPROP program, calculating two or four adjustable coefficients for each fluid. As a result, we propose recommended correlations for 99 acids, providing mean absolute percentage deviations below 1.6% in all cases.

  17. Stable carbon isotopic compositions of low-molecular-weight dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, and fatty acids: Implications for atmospheric processing of organic aerosols

    NASA Astrophysics Data System (ADS)

    Zhang, Yan-Lin; Kawamura, Kimitaka; Cao, Fang; Lee, Meehye

    2016-04-01

    Stable carbon isotopic compositions (δ13C) were measured for 23 individual organic species including 9 dicarboxylic acids, 7 oxocarboxylic acids, 1 tricarboxylic acid, 2 α-dicarbonyls, and 4 fatty acids in the aerosols from Gosan background site in East Asia. δ13C values of particle phase glyoxal and methylglyoxal are significantly larger than those previously reported for isoprene and other precursors. The values are consistently less negative in oxalic acid (C2, average -14.1‰), glyoxylic acid (-13.8‰), pyruvic acid (-19.4‰), glyoxal (-13.5‰), and methylglyoxal (-18.6‰) compared to other organic species (e.g., palmitic acid, -26.3‰), which can be explained by the kinetic isotope effects during atmospheric oxidation of pre-aged precursors (e.g., isoprene) and the subsequent gas-particle partitioning after the evaporation of clouds or wet aerosols. The δ13C values of C2 is positively correlated with C2 to organic carbon ratio, indicating that photochemical production of C2 is more pronounced than its degradation during long-range atmospheric transport. The isotopic results also suggest that aqueous phase oxidation of glyoxal and methylglyoxal is a major formation process of oxalic acid via the intermediates such as glyoxylic acid and pyruvic acid. This study provides evidence that organic aerosols are intensively photochemically aged in the western North Pacific rim.

  18. Organic and inorganic aerosol compositions in Ulaanbaatar, Mongolia, during the cold winter of 2007 to 2008: Dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls

    NASA Astrophysics Data System (ADS)

    Jung, Jinsang; Tsatsral, Batmunkh; Kim, Young J.; Kawamura, Kimitaka

    2010-11-01

    To investigate the distributions and sources of water-soluble organic acids in the Mongolian atmosphere, aerosol samples (PM2.5, n = 34) were collected at an urban site (47.92°N, 106.90°E, ˜1300 m above sea level) in Ulaanbaatar, the capital of Mongolia, during the cold winter. The samples were analyzed for water-soluble dicarboxylic acids (C2-C12) and related compounds (ketocarboxylic acids and α-dicarbonyls), as well as organic carbon (OC), elemental carbon, water-soluble OC, and inorganic ions. Distributions of dicarboxylic acids and related compounds were characterized by a predominance of terephthalic acid (tPh; 130 ± 51 ng m-3, 19% of total detected organic acids) followed by oxalic (107 ± 28 ng m-3, 15%), succinic (63 ± 20 ng m-3, 9%), glyoxylic (55 ± 18 ng m-3, 8%), and phthalic (54 ± 27 ng m-3, 8%) acids. Predominance of terephthalic acid, which has not been reported previously in atmospheric aerosols, was mainly due to uncontrolled burning of plastic bottles and bags in home stoves for heating and waste incineration during the cold winter. This study demonstrated that most of the air pollutants were directly emitted from local sources such as heat and power plants, home stoves, and automobiles. Development of an inversion layer (<700 m above ground level) over the basin of Ulaanbaatar accelerated the accumulation of pollutants, causing severe haze episodes during the winter season.

  19. Stable carbon isotopic compositions of low-molecular-weight dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, and fatty acids: implications for atmospheric processing of organic aerosols

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Kawamura, K.; Cao, F.; Lee, M.

    2015-12-01

    Stable carbon isotopic compositions (δ13C) were measured for 23 individual organic species including 9 dicarboxylic acids, 7 oxocarboxylic acids, 1 tricarboxylic acid, 2 α-dicarbonyls and 4 fatty acids in the aerosols from Gosan background site in East Asia. δ13C of particle-phase glyoxal and methylglyoxal are significantly higher than those previously reported for isoprene and other precursors, associated with isotope fractionation during atmospheric oxidation. 13C is consistently more enriched for oxalic acid (C2), glyoxylic acid, pyruvic acid, glyoxal and methylglyoxal compared to other organic compounds identified, which can be explained by the kinetic isotope effects during aqueous-phase processing and the subsequent gas-particle partitioning after clouds or wet aerosols evaporation δ13C of C2 is positively correlated with C2 and organic carbon ratio, indicating that a photochemical production of C2 is more pronounced than its degradation process during long-range transport. The 13C results also suggest that aqueous-phase oxidation of glyoxal and methylglyoxal is major formation process of oxalic acid production via the major intermediates glyoxylic acid and pyruvic acid. This study provides evidence that organic aerosols are intensively photo-chemically aged in this region.

  20. Longitudinal distributions of dicarboxylic acids, ω-oxoacids, pyruvic acid, α-dicarbonyls, and fatty acids in the marine aerosols from the central Pacific including equatorial upwelling

    NASA Astrophysics Data System (ADS)

    Hoque, Mir Md. Mozammal; Kawamura, Kimitaka

    2016-03-01

    Remote marine aerosol samples (total suspended particles) were collected during a cruise in the central Pacific from Japan to Mexico (1°59'N-35°N and 171°54'E-90°58'W). The aerosol samples were analyzed for dicarboxylic acids (C2-C11), ω-oxoacids, pyruvic acid, α-dicarbonyls, and fatty acids as well as organic and elemental carbon, water-soluble organic carbon, and total nitrogen (WSTN). During the study, diacids were the most abundant compound class followed by fatty acids, ω-oxoacids, and α-dicarbonyls. Molecular compositions of diacids showed a predominance of oxalic (C2) acid followed by malonic (C3) and succinic (C4) acids. Oxalic acid comprises 74% of total diacids. This result suggests that photochemical production of oxalic acid is significant over the central Pacific. Spatial distributions of diacids, ω-oxoacids, pyruvic acid, α-dicarbonyls, and fatty acids together with total carbon and WSTN showed higher abundances in the eastern equatorial Pacific where the upwelling of high-nutrient waters followed by high biological productivity is common, indicating that their in situ production is important in the warmer central Pacific through photochemical oxidation from their gaseous and particulate precursors. This study demonstrates that there is a strong linkage in biogeochemical cycles of carbon in the sea-air interface via ocean upwelling, phytoplankton productivity, sea-to-air emissions of organic matter, and formation of secondary organic aerosols in the eastern equatorial Pacific.

  1. Novel one-pot synthesis of dicarboxylic acids mediated alginate-zirconium biopolymeric complex for defluoridation of water.

    PubMed

    Prabhu, Subbaiah Muthu; Meenakshi, Sankaran

    2015-04-20

    The present investigation explains the fluoride removal from aqueous solution using alginate-zirconium complex prepared with respective dicarboxylic acids like oxalic acid (Ox), malonic acid (MA) and succinic acid (SA) as a medium. The complexes viz., alginate-oxalic acid-zirconium (Alg-Ox-Zr), alginate-malonic acid-zirconium (Alg-MA-Zr) and alginate-succinic acid-zirconium (Alg-SA-Zr) were synthesized and studied for fluoride removal. The synthesized complexes were characterized by FTIR, XRD, SEM with EDAX and mapping images. The effects of various operating parameters were optimized. The result showed that the maximum removal of fluoride 9653mgF(-)/kg was achieved by Alg-Ox-Zr complex at acidic pH in an ambient atmospheric condition. Equilibrium data of Alg-Ox-Zr complex was fitted well with Freundlich isotherm. The calculated values of thermodynamic parameters indicated that the fluoride adsorption is spontaneous and endothermic in nature. The mechanism of fluoride removal behind Alg-Ox-Zr complex has been proposed in detail. The suitability of the Alg-Ox-Zr complex has been tested with the field sample collected in a nearby fluoride endemic area.

  2. Fragmentation and dimerization of aliphatic amino acid films induced by vacuum ultraviolet irradiation

    NASA Astrophysics Data System (ADS)

    Tanaka, Masahito; Kaneko, Fusae; Koketsu, Toshiyuki; Nakagawa, Kazumichi; Yamada, Toru

    2008-10-01

    The chemical reaction of aliphatic amino acid, such as alanine (Ala) and leucine (Leu), in the solid phase induced by vacuum ultraviolet (VUV) irradiation was studied by high-performance liquid chromatography technique and mass spectroscopic method. Quantum efficiencies of dimerization of Ala in the solid phase obviously showed irradiated VUV wavelength dependence. The values of quantum efficiencies of formation of Ala dimer were determined to be 5.7×10-5, 1.3×10-3, and 2.4×10-4 for 208, 183, and 87 nm irradiation, respectively. VUV-induced fragment desorption from Ala and Leu films has also been examined by mass spectroscopic method. Observed mass spectra clearly indicated that both the deamination and decarboxylation reactions were common in both Ala and Leu films, and the dissociation of side chain occurred only in Leu film.

  3. Transition-metal-free visible-light photoredox catalysis at room-temperature for decarboxylative fluorination of aliphatic carboxylic acids by organic dyes.

    PubMed

    Wu, Xinxin; Meng, Chunna; Yuan, Xiaoqian; Jia, Xiaotong; Qian, Xuhong; Ye, Jinxing

    2015-07-28

    We report herein an efficient, general and green method for decarboxylative fluorination of aliphatic carboxylic acids. By using a transition-metal-free, organocatalytic photoredox system, the reaction of various aliphatic carboxylic acids with the Selectfluor reagent afforded the corresponding alkyl fluorides in satisfactory yields under visible light irradiation at room temperature.

  4. Gamma-irradiation stability of saturated and unsaturated aliphatic polyanhydrides--ricinoleic acid based polymers.

    PubMed

    Teomim, D; Mäder, K; Bentolila, A; Magora, A; Domb, A J

    2001-01-01

    The effect of terminal sterilization by gamma-irradiation on several ricinoleic acid based polyanhydrides was investigated. The following polymers were used: poly(ricinoleic acid maleate) [P(RAM)], poly(ricinoleic acid succinate) [P(RAS)], poly(hydroxy stearic acid succinate) [P(HSAS)], poly(hydroxy stearic acid maleate) [P(HSAM)], and their copolymers with sebacic acid. The polymers were irradiated with an absorbed dose of 2.5 or 10 Mrad by means of a 60Co source under dry ice or at room temperature. No differences were found between samples irradiated under dry ice and at room temperature. Polymers prepared from monomers containing maleate residues, which contain double bonds adjusted to the anhydride linkage along the polymer chain, decreased in molecular weight, became insoluble, and showed fast hydrolytic degradation. For example, p(RAM), p(HSAM), and their copolymers with sebacic acid decreased in Mw from about 10,000 to about 2000, and from about 30,000 to about 5000, respectively, while polymers based on RAS and HSAS remained stable. This phenomenon was explained by an anhydride interchange-self-depolymerization process of the unsaturated anhydride bonds induced by gamma-irradiation. This explanation was supported by the depolymerization of another class of polymers having an anhydride bond between two double bonds, fumaric acid anhydride polymers. The anhydride bond that lies between two double bonds was found to be more sensitive to gamma-irradiation. This anhydride bond may be cleaved to form two radicals that further react with aliphatic anhydride bonds along the polymer chain to form inter- and/or intracyclization products. PMID:11710004

  5. Aliphatic Hydrocarbons of Cladosporium resinae Cultured on Glucose, Glutamic Acid, and Hydrocarbons

    PubMed Central

    Walker, J. D.; Cooney, J. J.

    1973-01-01

    The carbon source markedly influenced the qualitative and quantitative composition of cellular hydrocarbons in Cladosporium resinae. Total lipid and hydrocarbon content was greater in cells grown on n-alkanes than in cells grown on glucose or glutamic acid. Glucose-grown cells contained a spectrum of aliphatic hydrocarbons from C7 to C36; pristane and n-hexadecane comprised 98% of the total. Cells grown on glutamic acid contained C7 to C23 hydrocarbons; n-tridecane, n-tetradecane, n-hexadecane, and pristane made up 74% of the total. n-Decane-grown cells yielded C8 to C32 compounds, and n-hexadecane (96%) was the major hydrocarbon. Cells grown on individual n-alkanes from C11 to C15 all contained C11 to C28 hydrocarbons, and cells grown on n-hexadecane contained C11 to C32 hydrocarbons. In n-undecane-grown cells, n-hexadecane and pristane made up 92% of the total, but in cells grown on C12 to C16 n-alkanes the major cellular hydrocarbon was the one on which the cells were grown. This suggests that cells cultured on n-alkanes of C12 or longer accumulate n-alkanes prior to oxidizing them. PMID:4762391

  6. Syntheses and Antibiotic Evaluation of 2-{[(2R,4R)-4-Carboxy-2-hydroxypyrrolidin-1-yl]carbonyl}benzene-1,5-dicarboxylic Acids and 2-Carbamoylbenzene-1,5-dicarboxylic Acid Analogues

    PubMed Central

    2016-01-01

    Our search for new antibiotics led to the syntheses and biological evaluation of new classes of dicarboxylic acid analogues. The syntheses involve nucleophilic addition of different substituted benzylamine, aniline, alkylamine, and 4-hydroxyl-L-proline with carbamoylbenzoic acid. The results of the antimicrobial activity as indicated by the zone of inhibition (ZOI) showed that Z10 is the most active against Pseudomonas aeruginosa (32 mm) and least active against Candida stellatoidea (27 mm) and Vancomycin Resistant Enterococci (VRE) (27 mm), while Z7 shows the least zone of inhibition (22 mm) against Methicillin Resistant Staphylococcus aureus (MRSA). The minimum inhibition concentration (MIC) determination reveals that Z10 inhibits the growth of tested microbes at a low concentration of 6.25 μg/mL, while Z9 and Z12 inhibits the growth of most microbes at a concentration of 12.5 μg/mL, recording the least MIC. The Minimum Bactericidal/Fungicidal Concentration (MBC/MFC) results revealed that Z10 has the highest bactericidal/fungicidal effect on the test microbes, at a concentration of 12.5 μg/mL, with the exception of Candida stellatoidea and Vancomycin Resistant Enterococci (VRE) with MBC/MFC of 25 μg/mL. The result of this investigation reveals the potential of the target compounds (Z1–3,5,7–12) in the search for new antimicrobial agents. PMID:26981281

  7. Syntheses and Antibiotic Evaluation of 2-{[(2R,4R)-4-Carboxy-2-hydroxypyrrolidin-1-yl]carbonyl}benzene-1,5-dicarboxylic Acids and 2-Carbamoylbenzene-1,5-dicarboxylic Acid Analogues.

    PubMed

    Tukur, Abdulrazaq; Bello, Isaac Asusheyi; Koorbanally, Neil Anthony; Habila, James Dama

    2016-01-01

    Our search for new antibiotics led to the syntheses and biological evaluation of new classes of dicarboxylic acid analogues. The syntheses involve nucleophilic addition of different substituted benzylamine, aniline, alkylamine, and 4-hydroxyl-L-proline with carbamoylbenzoic acid. The results of the antimicrobial activity as indicated by the zone of inhibition (ZOI) showed that Z 10 is the most active against Pseudomonas aeruginosa (32 mm) and least active against Candida stellatoidea (27 mm) and Vancomycin Resistant Enterococci (VRE) (27 mm), while Z 7 shows the least zone of inhibition (22 mm) against Methicillin Resistant Staphylococcus aureus (MRSA). The minimum inhibition concentration (MIC) determination reveals that Z 10 inhibits the growth of tested microbes at a low concentration of 6.25 μg/mL, while Z 9 and Z 12 inhibits the growth of most microbes at a concentration of 12.5 μg/mL, recording the least MIC. The Minimum Bactericidal/Fungicidal Concentration (MBC/MFC) results revealed that Z 10 has the highest bactericidal/fungicidal effect on the test microbes, at a concentration of 12.5 μg/mL, with the exception of Candida stellatoidea and Vancomycin Resistant Enterococci (VRE) with MBC/MFC of 25 μg/mL. The result of this investigation reveals the potential of the target compounds (Z 1-3,5,7-12 ) in the search for new antimicrobial agents. PMID:26981281

  8. Seasonal and rainfall-type variations in inorganic ions and dicarboxylic acids and acidity of wet deposition samples collected from subtropical East Asia

    NASA Astrophysics Data System (ADS)

    Tsai, Ying I.; Hsieh, Li-Ying; Kuo, Su-Ching; Chen, Chien-Lung; Wu, Pei-Ling

    2011-07-01

    Rainfall samples were collected over a period of 3 years and 8 months in subtropical East Asia. They are categorized into different rainfall types and analyzed to assess the ionic composition and its effect on the acidity of wet deposition in southern Taiwan. Only 4% of samples had a pH of <5.0, indicating that the study area is not impacted significantly by acid rain. The volume-weighted mean (VWM) pH by rainfall type was Spring Rain 5.74, Typhoon Rain 5.56, Summer Rain 5.46, Typhoon Outer Circulation (TOC) Rain 5.45, Plum Rain 5.32 and Autumn-Winter Rain 5.29. Dilution effects were important to the equivalent ionic concentration of different rainfall types. HCO 3-, SO 42- and Cl - were detected as major anions whereas NH 4+, Na + and Ca 2+ were major cations. CO 2-derived HCO 3- was the major ionic species in all but Typhoon Rain and Spring Rain, in which the major species were Na + and Cl - and Ca 2+, respectively. Excluding HCO 3-, the major species were NH 4+, Na + and Ca 2+ in Plum Rain, the secondary photochemical products SO 42-, NO 3- and NH 4+ in TOC Rain and Summer Rain, and Na + and Ca 2+ in Autumn-Winter Rain. Calculation of arithmetic means showed that dicarboxylic acids contributed between 0.25% and 0.53% of the total ionic concentration and of these, oxalic acid contributed the least (81.3% of the dicarboxylic acid) to TOC Rain and the most (96.1% of the dicarboxylic acid) to Spring Rain, suggestive of long-range transport in the latter. Differences in wet deposition composition were shown to be a result of differences in local emissions and long-range transport (hence of prevailing wind direction) during the period of rainfall and of the frequency and volume of rain that typifies each rainfall type. Principal component analysis (PCA) further revealed that traffic-related and industrial organic and inorganic pollutants, their secondary photochemical products, sea salts, and dust are important contributors to wet deposition. Moreover, the ratio of

  9. Molecular distributions and isotopic compositions of marine aerosols over the western North Atlantic: Dicarboxylic acids, ketoacids, α-dicarbonyls (glyoxal and methylglyoxal), fatty acids, sugars, and SOA tracers

    NASA Astrophysics Data System (ADS)

    Kawamura, K.; Ono, K.; Tachibana, E.; Quinn, P.; Bates, T. S.

    2013-12-01

    Marine aerosols were collected over the western North Atlantic from off the coast of Boston to Bermuda during the WACS (Western Atlantic Climate Study) cruise of R/V Ronald H. Brown in August 2012 using a high volume air sampler and pre-combusted quartz fiber filters. Aerosol filter samples (n=5) were analyzed for OC/EC, major inorganic ions, low molecular weight dicarboxylic acids and various secondary organic aerosol (SOA) tracers using carbon analyzer, ion chromatograph, GC/FID and GC/MS, respectively. Homologous series (C2-C12) of dicarboxylic acids (31-335 ng m-3) were detected with a predominance of oxalic acid. Total carbon and nitrogen and their stable isotope ratios were determined as well as stable carbon isotopic compositions of individual diacids using IRMS. Diacids were found to be the most abundant compound class followed by monoterpene-SOA tracers > isoprene-SOA tracers > sugar compounds > ketoacids > fatty alcohols > fatty acids > α-dicarbonyls > aromatic acids > n-alkanes. The concentrations of these compounds were higher in the coastal site and decreased in the open ocean. However, diacids stayed relatively high even in the remote ocean. Interestingly, contributions of oxalic acid to total aerosol carbon increased from the coast (2.3%) to the remote ocean (5.6%) during long-range atmospheric transport. Stable carbon isotopic composition of oxalic acid increased from the coast (-17.5‰) to open ocean (-12.4‰), suggesting that photochemical aging of organic aerosols occurred during the atmospheric transport over the ocean. Stable carbon isotope ratios of bulk aerosol carbon also increased from the coast near Boston to the open ocean near Bermuda.

  10. Atmospheric dry plus wet deposition and wet-only deposition of dicarboxylic acids and inorganic compounds in a coastal suburban environment

    NASA Astrophysics Data System (ADS)

    Tsai, Ying I.; Kuo, Su-Ching; Young, Li-Hao; Hsieh, Li-Ying; Chen, Pei-Ti

    2014-06-01

    This study investigated the chemical properties and composition sources of dicarboxylic organic acids and inorganic salts in dry plus wet deposition (DWD) and wet-only deposition at a coastal suburban area in southern Taiwan in 2008. DWD is the accumulation of dry deposition and wet deposition from the beginning of each new rain event, while wet-only deposition is the wet deposition from the beginning of each new rain event only. A total of 60 samples were collected during the period of study. The wet-only deposition samples were slightly more acidic (pH 5.01-5.50) than the DWD samples (pH 5.51-6.00). The total volume-weighted mean (VWM) equivalent ionic concentration of 784.3 ± 431.1 μeq L-1 in DWD was higher than that of 682.2 ± 392.4 μeq L-1 in wet-only deposition. In both types of deposition the major cation species were Ca2+, Na+ and NH4+, and the major anion species were HCO3-, Cl- and non-sea salt (nss) nss-SO42-. Total dicarboxylic acids contributed only 0.60% and 0.45% of the total ionic equivalent concentration in DWD and wet-only deposition, respectively, and oxalic and malonic acids were the major dicarboxylic acid species. DWD to wet-only deposition species concentration ratios (DWD/W ratios) were always higher than 1.0. DWD contained more water-soluble inorganic salts and dicarboxylic acids than wet-only deposition, with DWD/W ratios of the dust-bound species K+, Mg2+ and Ca2+ as large as 1.6-1.8 and those from photochemical species nss-SO42- and NH4+ of 1.36 and 1.29, respectively. These ratios show that the dry deposition flux of dust is greater than that of photochemical particles. In addition, the 1.81 ratio for oxalic acid shows that oxalic acid is easier to remove from the atmosphere via dry deposition than malonic and succinic acids. Probable deposition composition sources for both DWD and wet-only deposition, investigated using principal component analysis, were marine spray, photochemical inorganic products, and terrestrial origin and

  11. Marsh plant response to metals: Exudation of aliphatic low molecular weight organic acids (ALMWOAs)

    NASA Astrophysics Data System (ADS)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2016-03-01

    Metal exposure is known to induce the production and secretion of substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere by plant roots. Knowledge on this matter is extensive for soil plants but still considerably scarce regarding marsh plants roots adapted to high salinity media. Phragmites australis and Halimione portulacoides, two marsh plants commonly distributed in European estuarine salt marshes, were used to assess the response of roots of both species, in terms of ALMWOAs exudation, to Cu, Ni and Cd exposure (isolated and in mixture since in natural environment, they are exposed to mixture of metals). As previous studies were carried out in unrealistic and synthetic media, here a more natural medium was selected. Therefore, in vitro experiments were carried out, with specimens of both marsh plants, and in freshwater contaminated with two different Cu, Ni and Cd concentrations (individual metal and in mixture). Both marsh plants were capable of liberating ALMWOAs into the surrounding medium. Oxalic, citric and maleic acids were found in P. australis root exudate solutions and oxalic and maleic acids in H. portulacoides root exudate solutions. ALMWOA liberation by both plants was plant species and metal-dependent. For instance, Cu affected the exudation of oxalic acid by H. portulacoides and of oxalic and citric acids by P. australis roots. In contrast, Ni and Cd did not stimulate any specific response. Regarding the combination of all metals, H. portulacoides showed a similar response to that observed for Cu individually. However, in the P. australis case, at high metal concentration mixture, a synergetic effect led to the increase of oxalic acid levels in root exudate solution and to a decrease of citric acid liberation. A correlation between ALMWOAs exudation and metal accumulation could not be established. P. australis and H. portulacoides are considered suitable metal phytoremediators of estuarine impacted areas

  12. Gas/particle partitioning of low-molecular-weight dicarboxylic acids at a suburban site in Saitama, Japan

    NASA Astrophysics Data System (ADS)

    Bao, Linfa; Matsumoto, Mariko; Kubota, Tsutomu; Sekiguchi, Kazuhiko; Wang, Qingyue; Sakamoto, Kazuhiko

    2012-02-01

    Low-molecular-weight dicarboxylic acids (diacids) exhibit semivolatile behavior in the atmosphere, but their partitioning between the gaseous and particulate phases is still unclear. An annular denuder-filter pack system with a cyclone PM 2.5 was employed to investigate the gaseous and particulate phase concentrations of diacids, with high collection efficiency of most target compounds. Saturated diacids, unsaturated diacids, ketocarboxylic acids, and dicarbonyls were determined in gaseous and particulate samples collected from a suburban site in Japan, during 2007 summer, 2008 late-winter and early-winter. The concentrations of gaseous and particulate diacids in early-winter were lower than those in summer, but higher than those in late-winter. Individual diacid in gaseous phase showed a relatively good correlation with ambient oxidants, but a low correlation with NO gas (a primary pollutant). Particulate fraction to the total amount ( FP) of individual acid was larger in winter than in summer, and also was larger at night than in the daytime. In the same sample, individual diacid and ketocarboxylic acid had higher particulate phase occurrence ( FP > 56% in summer), whereas unsaturated diacid had higher gaseous phase occurrence ( FP < 18% in summer). In summer, gas/particle partitioning of diacids varied diurnally; FP values of oxalic and glyoxylic acids increased from their lowest values in the morning to their highest values at night, exhibiting the similar diurnal variation of relative humidity in the atmosphere. The higher humidity at night may lead to the formation of droplets in which water-soluble gaseous phases can dissolve, thus promoting gas-to-particle conversion. These results suggest that gas/particle partitioning of diacids depends not only on the concentrations in the gaseous phase by photochemical oxidation, but also on the characteristics of the atmosphere (e.g., temperature, sunlight, and relative humidity) and the aerosols (e.g., acidity

  13. Direct enantioseparation of underivatized aliphatic 3-hydroxyalkanoic acids with a quinine-based zwitterionic chiral stationary phase.

    PubMed

    Ianni, Federica; Pataj, Zoltán; Gross, Harald; Sardella, Roccaldo; Natalini, Benedetto; Lindner, Wolfgang; Lämmerhofer, Michael

    2014-10-10

    While aliphatic 2-hydroxyalkanoic acids have been more or less successfully enantioseparated with various chiral stationary phases by HPLC and GC, analogous applications on underivatized aliphatic 3-hydroxyalkanoic acids are completely absent in the scientific literature. With the aim of closing this gap, the enantioseparation of 3-hydroxybutyric acid, 3-hydroxydecanoic acid and 3-hydroxymyristic acid has been performed with two ion-exchange type chiral stationary phases (CSPs): one containing the anion-exchange type tert-butyl carbamoyl quinine chiral selector motif (Chiralpak QN-AX), and the other carrying the new zwitterionic variant based on trans-(S,S)-2-aminocyclohexanesulfonic acid-derivatized quinine carbamate (Chiralpak ZWIX(+)) as the chiral selector and enantiodiscriminating element, respectively. The zwitterionic enantiorecognition material provided better results in terms of enantioselectivity and resolution compared to the anion-exchanger CSP at reduced retention times due to the intramolecular counterion effect imposed by the sulfonic acid moiety and its competition with the 3-hydroxyalkanoic acid analyte for ionic interaction at the quininium-anion exchanger site. It is thus recommended as the CSP of first choice for enantioseparations of the class of aliphatic 3-hydroxyalkanoic acids. With use of polar organic eluent composed of ACN/MeOH/AcOH - 95/5/0.05 (v/v/v), a good compromise in terms of analysis time and enantioresolution quality was accomplished. The major experimental variables have been investigated for optimization of the resolution and allowed to derive information on the enantiorecognition mechanism. Corresponding Chiralpak ZWIX(-), based on pseudo-enantiomeric selector derived from quinidine and trans-(R,R)-2-aminocyclohexanesulfonic acid with opposite configurations provided reversed enantiomer elution orders. It has further to be stressed that these separations can be obtained with mass spectrometry compatible mobile phases.

  14. Colorimetric detection of Bi (III) in water and drug samples using pyridine-2,6-dicarboxylic acid modified silver nanoparticles.

    PubMed

    Mohammadi, Somayeh; Khayatian, Gholamreza

    2015-09-01

    A new selective, simple, fast and sensitive method is developed for sensing assay of Bi (III) using pyridine-2,6-dicarboxylic acid or dipicolinic acid (DPA) modified silver nanoparticles (DPA-AgNPs). Silver nanoparticles (AgNPs) were synthesized by reducing silver nitrate (AgNO3) with sodium borohydride (NaBH4) in the presence of DPA. Bismuth detection is based on color change of nanoparticle solution from yellow to red that is induced in the presence of Bi (III). Aggregation of DPA-AgNPs has been confirmed with UV-vis absorption spectra and transmission electron microscopy (TEM) images. Under the optimized conditions, a good linear relationship (correlation coefficient r=0.995) is obtained between the absorbance ratio (A525/A390) and the concentration of Bi (III) in the 0.40-8.00 μM range. This colorimetric probe allows Bi (III) to be rapidly quantified with a 0.01 μM limit of detection. The present method successfully applied to determine bismuth in real water and drug samples. Recoveries of water samples were in the range of 91.2-99.6%. PMID:25919329

  15. A novel method for determination of low molecular weight dicarboxylic acids in background atmospheric aerosol using ion chromatography.

    PubMed

    Tsai, Ying I; Hsieh, Li-Ying; Weng, Tzu-Hsiang; Ma, Yu-Chien; Kuo, Su-Ching

    2008-09-19

    This paper describes a novel gradient elution ion chromatographic method using a Dionex AS11 system for the determination of low molecular weight dicarboxylic acids (low-M(w) DCAs) in background atmospheric aerosol. Interference with the oxalic acid peak from sulfate in background PM(2.5) aerosol, 15.8 times the oxalic acid concentration, was remedied by removing sulfate using a barium cartridge, whilst interference with the malonic acid peak from carbonate was reduced by using a carbonate removal device. An alternative remedy to sulfate interference was use of an AS14 system using isocratic eluent, and this produced good resolution of oxalic acid from a high sulfate peak. In both the AS11 and the AS14 system, linear correlation coefficients were at all times >0.9990 with excellent linear range, the recoveries ranged from 92.8 to 106%, with relative standard deviation of 3.67-6.30%, whilst method detection limits (MDLs) ranged from 0.36microgL(-1) for malic acid to 3.87microgL(-1) for maleic acid. These data indicate that the analytical methods developed herein produce excellent separation efficiency and good determination of low-M(w) DCAs with satisfactory accuracy, recoveries, and MDLs. Samples left at room temperature (20 degrees C) for 300min in a simulation of the 'waiting time' involved in the proposed IC analysis decayed to between 86% (oxalic acid) and 39% (succinic and malonic acids) of their original concentration, whilst at 4 degrees C concentrations remained at 96-101% of original, indicating that maintaining samples at a low temperature prior to injection into the IC analyzer is vital for obtaining accurate results when analyzing low-M(w) DCAs. Oxalic acid was found to be the most prevalent low-M(w) DCA in background aerosol, comprising 57% of the total low-M(w) DCAs and 0.959% of the PM(2.5) aerosol mass, followed by succinic acid and malonic acid.

  16. Structure of seven organic salts assembled from 2,6-diaminopyridine with monocarboxylic acids, dicarboxylic acids, and tetracarboxylic acids

    NASA Astrophysics Data System (ADS)

    Gao, Xingjun; Zhang, Huan; Wen, Xianhong; Liu, Bin; Jin, Shouwen; Wang, Daqi

    2015-08-01

    Studies concentrating on non-covalent interactions between the organic base of 2,6-diaminopyridine, and carboxylic acids have led to an increased understanding of the role 2,6-diaminopyridine in binding with carboxylic acid derivatives. Here anhydrous and hydrated multi-component organic acid-base salts of 2,6-diaminopyridine have been prepared with the carboxylic acids as nicotinic acid, o-chlorobenzoic acid, 1,3-benzodioxole-5-carboxylic acid, 3,5-dinitrosalicylic acid, 4-nitro-phthalic acid, 1,4-cyclohexanedicarboxylic acid, and butane-1,2,3,4-tetracarboxylic acid. The seven crystalline compounds were characterized by X-ray diffraction analysis, infrared (IR), melting point (mp), and elemental analysis. All structures adopted the hetero R22(8) supramolecular synthons. The supramolecular architectures bear extensive Nsbnd H⋯N, Osbnd H⋯N, Osbnd H⋯O, Nsbnd H⋯O, and CH⋯O associations as well as other nonbonding contacts as CHsbnd N, CH2sbnd O, π-π, C-π, O-π, Cl-π, Clsbnd O, and Osbnd O interactions. The role of weak and strong hydrogen bonding in the crystal packing is ascertained.

  17. The influence of dicarboxylic acids: Oxalic acid and tartaric acid on the compressive strength of glass ionomer cements

    NASA Astrophysics Data System (ADS)

    Permana, Ahmadi Jaya; Setyawati, Harsasi; Hamami, Murwani, Irmina Kris

    2016-03-01

    Glass ionomer cement (GIC) has limitation on the mechanical properties especially compressive strength. The change of compressive strength of GIC by adding oxalic acid and tartaric acid has been investigated. Oxalic acid and tartaric acid was added to the liquid components at concentrations of 0 - 15% (w/w). Powder component of GIC was made from optimum experimental powder glass SiO2-Al2O3-CaF2. GIC was characterized by compressive strength test, SEM-EDX and FTIR. The addition of tartaric acid to GIC has greater improvement than addition of oxalic acid. The addition of tartaric acid at 10 % (w/w) to GIC has greatest value of compressive strength.

  18. Analysis of. gamma. -radiolysis products of aqueous solutions of esters of aliphatic amino acids by the PMR method

    SciTech Connect

    Panin, V.I.; Sidorov, P.S.; Usatyi, A.F.

    1987-09-01

    The ..gamma..-radiolysis of aqueous solutions of methyl esters of aliphatic amino acids and peptides was investigated by the method of nuclear (proton) magnetic resonance (PMR). The resonance lines appearing in the PMR spectra of the irradiated systems were identified, and a conclusion was drawn about the molecular structure of the radiolysis products. The kinetics of the accumulation of radiolysis products was studied, and the values of their radiation yields were estimated.

  19. Kinetics of aluminum and sulfate release from forest soil by mono- and diprotic aliphatic acids

    SciTech Connect

    Evans, A. Jr.; Zelazny, L.W. )

    1990-06-01

    A batch equilibration study evaluated the influence of naturally occurring low-molecular-weight mono- and diprotic aliphatic acids on the rate of Al and SO{sub 4}{sup 2{minus}} release in a Cecil soil (Typic Hapludult). The authors adjusted the pH of the organic acids (OAs) and of the soil suspension (3.8% w/w) to pH 4.0 and allowed them to equilibrate thermally before the experiment. After rapid addition of OAs to the soil suspension, they took solution samples at various time intervals and analyzed for Al, SO{sub 4}{sup 2{minus}}, and OA concentration. The initial concentration of OA in suspension was 1 {times} 10{sup {minus}5} mol liter{sup {minus}1}. Both Al and SO{sub 4}{sup 2{minus}} release followed pseudo-first-order kinetics, whereas OA adsorption obeyed simple first-order kinetics. The rate of Al release (k{sub 1}) was more rapid for the diprotic OA treatment (20.4 {times} 10{sup {minus}8} mol s{sup {minus}1}), as was SO{sub 4}{sup 2{minus}} release (1.63 {times} 10{sup {minus}8} mol s{sup {minus}1}), compared to the monoprotic OA treatment. The rate of Al release varied inversely with OA chain length and the distance between -COOH functional groups. The addition of substituent -OH groups between the -COOH groups further reduced K{sub 1}. A similar trend was observed for the rate of SO{sub 4}{sup 2{minus}} release (k{sub 1}) into solution. Monoprotic OAs were more rapidly adsorbed to the particle surfaces than were diprotic OAs. The authors postulate that removal of Al and SO{sub 4}{sup 2{minus}} from solution occurs via selective mineral precipitation.

  20. Formation of water-soluble dicarboxylic acids, oxoacids and a-dicarbonyls by ozone oxidation of isoprene

    NASA Astrophysics Data System (ADS)

    Kawamura, K.; Tachibana, E.; Sakamoto, Y.; Hirokawa, J.

    2014-12-01

    Water-soluble dicarboxylic acids such as oxalic acid (C2) are the dominant organic compound class in atmospheric aerosols. They can act as cloud condensation nuclei and affect on the Earth climate. Diacids can be primary emitted from fossil fuel combustion and biomass burning and secondarily produced by photochemical oxidations of biogenic and anthropogenic hydrocarbons. However, their sources and formation processes are still not well understood. Recently model and observation studies suggested the importance of isoprene as a precursor of oxalic acid. Isoprene is the most abundant BVOC emitted from terrestrial plants and can serve as important precursors of diacids. We conducted a laboratory oxidation of isoprene (2.0 ppm) with ozone (4.3 ppm) in a Teflon bag for 10 to 480 min. The formed particles were collected with quartz fiber filters and analyzed for diacids, oxoacids and a-dicarbonyls employing water extraction and butyl ester derivatization and using GC and GC/MS techniques. Here, we report the analytical results to better understand the formation process of diacids and related compounds from isoprene. We detected homologous series of saturated diacids (C2-C6), unsaturated diacids (maleic and methylmaleic acids), w-oxocarboxylic acids (C2-C9), pyruvic acid, glyoxal and methylglyoxal. We found that oxalic acid (3000-9700 ngm-3) is the most abundant diacid followed by succinic (C4) or malonic (C3) acid. Their concentrations increased with reaction time showing a maximum in 4 hours. Interestingly, C3/C4 ratios increased with time. The second most abundant species after oxalic acid was generally methylglyoxal (3600-9600 ngm-3), except for the 30 min. sample where methylglyoxal was more abundant than oxalic acid. Glyoxylic acid (wC2) was found as the most abundant oxoacid (1600-3800 ngm-3) followed by wC3 and wC4. Although the concentrations of diacids and related compounds are 1-2 orders magnitude higher than those reported in ambient aerosols, this study

  1. Poly[diaqua(μ(2)-3-carboxypyrazine-2-carboxylato)(μ(2)-pyrazine-2,3-dicarboxylic acid)potassium(I)].

    PubMed

    Tombul, Mustafa; Güven, Kutalmis; Svoboda, Ingrid

    2007-01-01

    The structural unit of the title compound, [K(C(6)H(3)N(2)O(4))(C(6)H(4)N(2)O(4))(H(2)O)(2)](n), consists of one potassium cation, one hydrogen pyrazine-2,3-dicarboxyl-ate anion, one pyrazine-2,3-dicarboxylic acid mol-ecule and two water mol-ecules; this is twice the asymmetric unit, since the potassium cation lies on an inversion centre. Each anion or acid mol-ecule is linked to two potassium cations, while the potassium cation has contacts to four symmetry-equivalent organic ligands, with two different coordination modes towards this cation. In addition, each potassium cation is coordinated by two water O atoms, raising the coordination number to eight. One of the carboxyl groups of the acid retains its H atom, which forms a hydrogen bond to a coordinated water mol-ecule. The other carboxyl group is deprotonated in half of the ligands and protonated in the other half, taking part in a strong O-H⋯O hydrogen bond disordered over an inversion centre. The stabilization of the crystal structure is further assisted by O-H⋯O and O-H⋯N hydrogen bonds in which water acts as the donor. PMID:21200587

  2. catena-Poly[[diaqua-rubidium(I)](μ(2)-3-carboxy-pyrazine-2-carboxyl-ato)(μ(2)-pyrazine-2,3-dicarboxylic acid)].

    PubMed

    Tombul, Mustafa; Guven, Kutalmis

    2009-01-01

    The structural unit of the title compound, [Rb(C(6)H(3)N(2)O(4))(C(6)H(4)N(2)O(4))(H(2)O)(2)](n), consists of one rubidium cation, one hydrogen pyrazine-2,3-dicarboxyl-ate anion, one pyrazine-2,3-dicarboxylic acid mol-ecule and two water mol-ecules. This formulation is repeated twice in the asymmetric unit as the rubidium cation lies on an inversion centre. Each anion or acid mol-ecule is linked to two rubidium cations, while the rubidium cation has close contacts to four symmetry-equivalent organic ligands, with two different coordination modes towards this cation. In addition, each rubidium cation is coordinated by two water O atoms, raising the coordination number to eight. One of the carboxyl groups of the acid holds its H atom, which forms a hydrogen bond to a coordinated water mol-ecule. The other carboxyl group is deprotonated in half of the ligands and protonated in the other half, taking part in a strong O-H⋯O hydrogen bond disordered over an inversion centre. The stabil-ization of the crystal structure is further assisted by O-H⋯O and O-H⋯N hydrogen-bonding inter-actions involving the water mol-ecules and carboxyl-ate O atoms. PMID:21581808

  3. Specific chiral sensing of amino acids using induced circularly polarized luminescence of bis(diimine)dicarboxylic acid europium(III) complexes.

    PubMed

    Okutani, Kazuhiro; Nozaki, Koichi; Iwamura, Munetaka

    2014-06-01

    The circularly polarized luminescence (CPL) from [Eu(pda)2](-) (pda = 1,10-phenanthroline-2,9-dicarboxylic acid) and [Eu(bda)2](-) (bda = 2,2'-bipyridine-6,6'-dicarboxylic acid) in aqueous solutions containing various amino acids was investigated. The europium(III) complexes exhibited bright-red luminescence assignable to the f-f transition of the Eu(III) ion when irradiated with UV light. Although the luminescence was not circularly polarized in the solid state or in aqueous solutions, in accordance with the achiral crystal structure, the complexes exhibited detectable induced CPL (iCPL) in aqueous solutions containing chiral amino acids. In the presence of L-pyrrolidonecarboxylic acid, both [Eu(pda)2](-) and [Eu(bda)2](-) showed similar iCPL intensity (glum ∼ 0.03 for the (5)D0 → (7)F1 transition at 1 mol·dm(-3) of the amino acid). On the other hand, in the presence of L-histidine or L-arginine, [Eu(pda)2](-) exhibited intense CPL (glum ∼ 0.08 for the (5)D0 → (7)F1 transition at 0.10 mol·dm(-3) of the amino acid), whereas quite weak CPL was observed for [Eu(bda)2](-) under the same conditions (glum < 0.01). On the basis of analysis of the iCPL intensities in the presence of 12 amino acids, [Eu(pda)2](-) was found to be a good chiral CPL probe with high sensitivity (about 10(-2) mol·dm(-3)) and high selectivity for L-histidine at pH 3 and for L-arginine at pH 7. The mechanism of iCPL was evaluated by analysis of the fine structures in the luminescence spectra and the amino acid concentration dependence of glum. For the [Eu(pda)2](-)-histidine/arginine systems, the europium(III) complexes possess coordination structures similar to that in the crystal with slight distortion to form a chiral structure due to specific interaction with two zwitterionic amino acids. This mechanism was in stark contrast to that of the europium(III) complex-pyrrolidonecarboxylic acid system in which one amino acid coordinates to the Eu(III) ion to yield an achiral coordination

  4. Low-temperature heat capacities and standard molar enthalpy of formation of pyridine-2,6-dicarboxylic acid

    NASA Astrophysics Data System (ADS)

    Yang, Wei-Wei; Di, You-Ying; Kong, Yu-Xia; Tan, Zhi-Cheng

    2010-06-01

    This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of heat capacities as a function of temperature was fitted by the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K. The constant-volume energy of combustion of the compound was determined by means of a precision rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion of the compound was derived from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound was calculated from a combination of the datum of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.

  5. Piperazine-2,3-dicarboxylic acid Derivatives as Dual Antagonists of NMDA and GluK1-Containing Kainate Receptors

    PubMed Central

    Irvine, Mark W.; Costa, Blaise M.; Dlaboga, Daniel; Culley, Georgia; Hulse, Richard; Scholefield, Caroline L.; Atlason, Palmi; Fang, Guangyu; Eaves, Richard; Morley, Richard; Mayo-Martin, Maria B.; Amici, Mascia; Bortolotto, Zuner A.; Donaldson, Lucy; Collingridge, Graham L.; Molnár, Elek; Monaghan, Daniel T.; Jane, David E.

    2011-01-01

    Competitive N-methyl-D-aspartate receptor (NMDAR) antagonists bind to the GluN2 subunit, of which there are four types (GluN2A-D). We report that some N1-substituted derivatives of cis-piperazine-2,3-dicarboxylic acid display improved relative affinity for GluN2C and GluN2D versus GluN2A and GluN2B. These derivatives also display subtype-selectivity among the more distantly related kainate receptor family. Compounds 18i and (−)-4 were the most potent kainate receptor antagonists and 18i was selective for GluK1 versus GluK2, GluK3 and AMPA receptors. Modeling studies revealed structural features required for activity at GluK1 subunits and suggested that S674 was vital for antagonist activity. Consistent with this hypothesis, replacing the equivalent residue in GluK3 (alanine) with a serine imparts 18i antagonist activity. Antagonists with dual GluN2D and GluK1 antagonist activity may have beneficial effects in various neurological disorders. Consistent with this idea, antagonist 18i (30 mg/Kg i.p.) showed antinociceptive effects in an animal model of mild nerve injury. PMID:22111545

  6. Genome-scale metabolic modeling and in silico analysis of lipid accumulating yeast Candida tropicalis for dicarboxylic acid production.

    PubMed

    Mishra, Pranjul; Park, Gyu-Yeon; Lakshmanan, Meiyappan; Lee, Hee-Seok; Lee, Hongweon; Chang, Matthew Wook; Ching, Chi Bun; Ahn, Jungoh; Lee, Dong-Yup

    2016-09-01

    Recently, the bio-production of α,ω-dicarboxylic acids (DCAs) has gained significant attention, which potentially leads to the replacement of the conventional petroleum-based products. In this regard, the lipid accumulating yeast Candida tropicalis, has been recognized as a promising microbial host for DCA biosynthesis: it possess the unique ω-oxidation pathway where the terminal carbon of α-fatty acids is oxidized to form DCAs with varying chain lengths. However, despite such industrial importance, its cellular physiology and lipid accumulation capability remain largely uncharacterized. Thus, it is imperative to better understand the metabolic behavior of this lipogenic yeast, which could be achieved by a systems biological approach. To this end, herein, we reconstructed the genome-scale metabolic model of C. tropicalis, iCT646, accounting for 646 unique genes, 945 metabolic reactions, and 712 metabolites. Initially, the comparative network analysis of iCT646 with other yeasts revealed several distinctive metabolic reactions, mainly within the amino acid and lipid metabolism including the ω-oxidation pathway. Constraints-based flux analysis was, then, employed to predict the in silico growth rates of C. tropicalis which are highly consistent with the cellular phenotype observed in glucose and xylose minimal media chemostat cultures. Subsequently, the lipid accumulation capability of C. tropicalis was explored in comparison with Saccharomyces cerevisiae, indicating that the formation of "citrate pyruvate cycle" is essential to the lipid accumulation in oleaginous yeasts. The in silico flux analysis also highlighted the enhanced ability of pentose phosphate pathway as NADPH source rather than malic enzyme during lipogenesis. Finally, iCT646 was successfully utilized to highlight the key directions of C. tropicalis strain design for the whole cell biotransformation application to produce long-chain DCAs from alkanes. Biotechnol. Bioeng. 2016;113: 1993-2004.

  7. Water-soluble organic carbon, dicarboxylic acids, ketoacids, and α-dicarbonyls in the tropical Indian aerosols

    NASA Astrophysics Data System (ADS)

    Pavuluri, Chandra Mouli; Kawamura, Kimitaka; Swaminathan, T.

    2010-06-01

    Tropical aerosol (PM10) samples (n = 49) collected from southeast coast of India were studied for water-soluble dicarboxylic acids (C2-C12), ketocarboxylic acids (C2-C9), and α-dicarbonyls (glyoxal and methylglyoxal), together with analyses of total carbon (TC) and water-soluble organic carbon (WSOC). Their distributions were characterized by a predominance of oxalic acid followed by terephthalic (t-Ph), malonic, and succinic acids. Total concentrations of diacids (227-1030 ng m-3), ketoacids (16-105 ng m-3), and dicarbonyls (4-23 ng m-3) are comparative to those from other Asian megacities such as Tokyo and Hong Kong. t-Ph acid was found as the second most abundant diacid in the Chennai aerosols. This feature has not been reported previously in atmospheric aerosols. t-Ph acid is most likely derived from the field burning of plastics. Water-soluble diacids were found to contribute 0.4%-3% of TC and 4%-11% of WSOC. Based on molecular distributions and backward air mass trajectories, we found that diacids and related compounds in coastal South Indian aerosols are influenced by South Asian and Indian Ocean monsoons. Organic aerosols are also suggested to be significantly transported long distances from North India and the Middle East in early winter and from Southeast Asia in late winter, but some originate from photochemical reactions over the Bay of Bengal. In contrast, the Arabian Sea, Indian Ocean, and South Indian continent are suggested as major source regions in summer. We also found daytime maxima of most diacids, except for C9 and t-Ph acids, which showed nighttime maxima in summer. Emissions from marine and terrestrial plants, combined with land/sea breezes and in situ photochemical oxidation, are suggested especially in summer as an important factor that controls the composition of water-soluble organic aerosols over the southeast coast of India. Regional emissions from anthropogenic sources are also important in megacity Chennai, but their influence is

  8. Scavenging of SO 4- radical anions by mono- and dicarboxylic acids in the Mn(II)-catalyzed S(IV) oxidation in aqueous solution

    NASA Astrophysics Data System (ADS)

    Grgić, Irena; Podkrajšek, Boštjan; Barzaghi, Paolo; Herrmann, Hartmut

    The rate constants for reactions of the SO 4- radical anion with some low molecular weight monocarboxylic acids (MCAs) and dicarboxylic acids (DCAs) and their anions using the laser flash photolysis-long path laser absorption (LFP-LPLA) technique were determined. The present study contains the first measured rate constants for SO 4- reactions with glycolic, lactic, malic and malonic acid. The rate constants are found to be in the range from 10 5 to 10 7 M -1 s -1, with the lower values found for acids and higher values for their respective anions. In addition, the rate constants for scavenging of SO 4- by all investigated organics in the Mn(II)-catalyzed S(IV) autoxidation at pH 4.5 and T=25 °C were determined by means of the reversed rate method. The comparison between these rate constants and the rate constants obtained by direct measurements confirms the proposed inhibiting mechanism for the Mn(II)-catalyzed S(IV) autoxidation in the presence of monocarboxylic acids. In the case of formic acid, which causes the highest inhibition, this mechanism can explain the second part of kinetic traces (i.e. after the induction period). Surprisingly, although dicarboxylic acids are reactive toward SO 4- they do not contribute to the inhibition of S(IV) oxidation (especially malic and malonic acids).

  9. Ion-Exclusion High-Performance Liquid Chromatography of Aliphatic Organic Acids Using a Surfactant-Modified C18 Column.

    PubMed

    Fasciano, Jennifer M; Mansour, Fotouh R; Danielson, Neil D

    2016-07-01

    Ion exclusion chromatography (IELC) of short chain aliphatic carboxylic acids is normally done using a cation exchange column under standard HPLC conditions but not in the ultra-HPLC (UHPLC) mode. A novel IELC method for the separation of this class of carboxylic acids by either HPLC or UHPLC utilizing a C18 column dynamically modified with sodium dodecyl sulfate has been developed. The sample capacity is estimated to be near 10 mM for a 20 µL injection or 0.2 µmol using a 150 × 4.6 mm column. The optimum mobile phase determined for three standard mixtures of organic acids is 1.84 mM sulfuric acid at pH 2.43 and a flow rate of 0.6 mL/min. Under optimized conditions, a HPLC separation of four aliphatic carboxylic acids such as tartaric, malonic, lactic and acetic can be achieved in under 4 min and in <2 min in the UHPLC mode at 2.1 mL/min. A variety of fruit juice and soft drink samples are analyzed. Stability of the column as measured by the retention order of maleic and fumaric acid is estimated to be ∼4,000 column volumes using HPLC and 600 by UHPLC. Reproducible chromatograms are achieved over at least a 2-month period. This study shows that the utility of a C18 column can be easily extended when needed to IELC under either standard or UHPLC conditions.

  10. Field Observation of Heterogeneous Formation of Dicarboxylic acids, Keto-carboxylic acids, α-Dicarbonyls and Nitrate in Xi'an, China during Asian dust storm periods

    NASA Astrophysics Data System (ADS)

    Wang, G.; Wang, J.; Ren, Y.; Li, J.

    2015-12-01

    To understand the formation mechanism of secondary organic aerosols (SOA) on dust surfaces, this study investigated the concentrations and compositions of dicarboxylic acids (C2-C11), keto-carboxylic acids (C3-C7), α-dicarbonyls and inorganic ions in size-segregated aerosols (9-stages) collected in Xi'an, China during the nondust storm and dust storm periods of 2009 and 2011. During the events the ambient particulate dicarboxylic acids were 932-2240 ng m-3, which are comparable and even higher than those in nondust periods. Molecular compositions of the above SOA are similar to those in nondust periods with oxalic acid being the leading species. In the presence of the dust storms, all the above mentioned SOA species in Xi'an were predominantly enriched on the coarse particles (>2.1μm), and oxalic acid well correlated with NO3- (R2=0.72, p<0.001) rather than SO42-.This phenomenon differs greatly from the SOA in any other nondust period that is characterized by an enrichment of oxalic acid in fine particles and a strong correlation of oxalic acid with SO42-. Our results further demonstrate that NO3- in the dust periods in Xi'an was mostly derived from secondary oxidation, whereas SO42- during the events was largely derived from surface soil of Gobi deserts. We propose a formation pathway to explain these observations, in which nitric acid and/or nitrogen oxides react with dust to produce Ca(NO3)2 and form a liquid phase on the surface of dust aerosols via water vapor-absorption of Ca(NO3)2, followed by a partitioning of the gas-phase water-soluble organic precursors (e.g.,glyoxal and methylglyoxal) into the aqueous-phase and a subsequent oxidation into oxalic acid. To the best of our knowledge, we found for the first time the enrichment of glyoxal and methylglyoxal on dust surface. Our data suggest an important role of nitrate in the heterogeneous formation process of SOA on the surface of Asian dust.

  11. Diurnal variations of total carbon, dicarboxylic acids, ketoacids and α-dicarbonyls in aerosols in the northern vicinity of Beijing

    NASA Astrophysics Data System (ADS)

    He, N.; Kawamura, K.; Okuzawa, K.; Kanaya, Y.; Wang, Z. F.

    2013-06-01

    Aerosol samples (TSP, n=58) were collected on day- and night-time basis at Mangshan in the north of Beijing, China in autumn 2007 to better understand the status of air quality and the influence of urban pollutants in the northern vicinity of Beijing. The samples were analyzed for aerosol mass, total carbon (TC), low molecular weight α, ω-dicarboxylic acids (C2-C12), ketoacids (ωC2-ωC9, pyruvic acid), α-dicarbonyls (glyoxal and methylglyoxal), as well as aromatic (phthalic, iso- and tere-phthalic) diacids. Aerosol mass and TC concentrations are higher in daytime than in nighttime. TC/aerosol mass ratios in this study are lower than those reported in megacities in East Asia, but higher than those reported in marine aerosols. Molecular distributions of diacids demonstrated that oxalic (C2) acid was the most abundant species, comprising 38-77% of total diacids, followed by succinic (C4) and malonic (C3) acids. For most compounds, the concentrations were higher in daytime than nighttime, indicating that diacids are produced in daytime by photochemical oxidation of organic precursors emitted from anthropogenic sources in Beijing during the transport to Mangshan area by the northward wind. However, we found that C2 concentrations are higher in nighttime than in daytime. A positive correlation of C2 to glyoxylic acid (ωC2) was obtained at night when relative humidity increased up to 100%, suggesting that aqueous phase production of C2 occurs in nighttime via the oxidation of ωC2. Depletion of C2 by photolysis of Fe-oxalato complexes might be another reason for the lower concentrations of C2 in daytime samples. High phthalic acid/C4 ratios in the aerosol samples suggest that automobile combustion and coal burning products are important sources, which are subjected to photochemical oxidation during the atmospheric transport of urban aerosols from Beijing. In contrast, higher concentrations of methylglyoxal in nighttime than daytime may suggest that isoprene emitted

  12. Molecular composition of dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids in atmospheric aerosols from Tanzania, East Africa during wet and dry seasons

    NASA Astrophysics Data System (ADS)

    Mkoma, S. L.; Kawamura, K.

    2013-02-01

    Atmospheric aerosol samples of PM2.5 and PM10 were collected during the wet and dry seasons in 2011 from a rural site in Tanzania and analysed for water-soluble dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, and fatty acids using a gas chromatography/flame ionization detector (GC/FID) and GC/mass spectrometry. Here we report the molecular composition and sources of diacids and related compounds for wet and dry seasons. Oxalic acid (C2) was found as the most abundant diacid species followed by succinic and/or malonic acids whereas glyoxylic acid and glyoxal were the dominant ketoacid and α-dicarbonyl, respectively in both seasons in PM2.5 and PM10. Mean concentration of C2 in PM2.5 (121 ± 47 ng m-3) was lower in wet season than dry season (258 ± 69 ng m-3). Similarly, PM10 samples showed lower concentration of C2 (169 ± 42 ng m-3) in wet season than dry season (292 ± 165 ng m-3). Relative abundances of C2 in total diacids were 65% and 67% in PM2.5 and 65% and 64% in PM10 in the wet and dry seasons, respectively. Total concentrations of diacids (289-362 ng m-3), ketoacids (37.8-53.7 ng m-3), and α-dicarbonyls (5.7-7.8 ng m-3) in Tanzania are higher than those reported at a rural background site in Nylsvley (South Africa) but comparable or lower than those reported from sites in Asia and Europe. Diacids and ketoacids were found to be present mainly in PM2.5 in both seasons (total α-dicarbonyls in the dry season), suggesting a production of organic acids from pyrogenic sources and photochemical oxidations. Averaged contributions of total diacids to aerosol total carbon were 1.4% in PM2.5 and 2.1% in PM10 during wet season and 3.3% in PM2.5 and 3.9% in PM10 during dry season whereas those to water-soluble organic carbon were 2.2% and 4.7% in PM2.5 during wet season and 3.1% and 5.8% in PM10 during dry season. The higher ratios in dry season suggest an enhanced photochemical oxidation of organic precursors probably via heterogeneous reactions on

  13. Stable vesicles composed of monocarboxylic or dicarboxylic fatty acids and trimethylammonium amphiphiles.

    PubMed

    Caschera, F; Bernardino de la Serna, J; Löffler, P M G; Rasmussen, T E; Hanczyc, M M; Bagatolli, L A; Monnard, P-A

    2011-12-01

    The self-assembly of cationic and anionic amphiphile mixtures into vesicles in aqueous media was studied using two different systems: (i) decanoic acid and trimethyldecylammonium bromide and (ii) hexadecanedioic acid (a simple bola-amphiphile) and trimethyldecylammonium bromide. The resulting vesicles with varying amphiphile ratios were characterized using parameters such as the critical vesicle concentration, pH sensitivity, and encapsulation efficiency. We also produced and observed giant vesicles from these mixtures using the electroformation method and confocal microscopy. The mixed catanionic vesicles were shown to be more stable than those formed by pure fatty acids. Those containing bola-amphiphile even showed the encapsulation of a small hydrophilic solute (8-hydroxypyrene-1,3,6-trisulfonic-acid), suggesting a denser packing of the amphiphiles. Compression and kinetics analysis of monolayers composed of these amphiphiles mixtures at the air/water interface suggests that the stabilization of the structures can be attributed to two main interactions between headgroups, predominantly the formation of hydrogen bonds between protonated and deprotonated acids and the additional electrostatic interactions between ammonium and acid headgroups. PMID:21932777

  14. Structures and physical properties of the cocrystals of adefovir dipivoxil with dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Jung, Sungyup; Lee, Jonghwi; Kim, Il Won

    2013-06-01

    The cocrystallization of adefovir dipivoxil (AD) with suberic acid (SUB) or succinic acid (SUC) was examined. X-ray diffraction was used to determine the structures of AD/SUB and AD/SUC cocrystals. Both cocrystals were formed via multiple hydrogen bonds between the adenine part of AD and the carboxylic acid groups of SUB or SUC. Longer SUB effectively dispersed AD molecules, and AD hydrogen-bonded only to SUB. When shorter SUC was used, AD formed hydrogen bonding with both SUC and adjacent AD. As a result, the cocrystal compositions were AD/SUB=1:1 and AD/SUC=2:1. Both cocrystals displayed superior thermal stability and increased aqueous solubility. The present study demonstrated that the adenine and similar structures of active pharmaceutical ingredients could be used to produce cocrystals of improved physical properties.

  15. Copper(II)-lanthanide(III) coordination polymers constructed from pyridine-2,5-dicarboxylic acid: Preparation, crystal structure and photoluminescence

    NASA Astrophysics Data System (ADS)

    Xia, Zheng-Qiang; Wei, Qing; Chen, San-Ping; Feng, Xin-Ming; Xie, Gang; Qiao, Cheng-Fang; Zhang, Guo-Chun; Gao, Sheng-Li

    2013-01-01

    A series of 3d-4f heterometallic coordination polymers, formulated as {[Cu3Ln2(pydc)6(H2O)12]·4H2O}n [Ln=Tb (1), Eu (2), Dy (3), Ho (4), Lu (5)], {[CuNd2(pydc)4(H2O)3]·H2O}n (6) and {[Cu3Pr2(pydc)6(H2O)13]·4H2O}n (7) (where H2pydc=pyridine-2,5-dicarboxylic acid), have been hydrothermally prepared by reactions of H2pydc ligand with lanthanide ions in the presence of Cu(II) ion. X-ray crystal structure analysis reveals that these compounds exhibit rich structural chemistry. 1-5 are isomorphous and present a two-dimensional network constructed from Ln2Cu2L2(H2O)2 SBU rings and CuL2(H2O) building blocks. In 6, two-dimensional ladder-like layers based on Nd(III) belts and CuL2O2 units are assembled by H2pydc ligands into a three-dimensional open framework. Polymer 7 displays a two-dimensional wave-like layer structure containing two distinct ring units, in which a new coordination mode of the pydc2- ligand is observed. The results indicate that the coordination flexibility of the pydc2- ligand and lanthanide contraction effect play cooperative roles in the formation of coordination polymers with different polymeric architectures. Compounds 1-2 exhibit intense green and red luminescence emission characteristics of Tb(III) and Eu(III), respectively. Furthermore, elemental analyses (EA), infrared spectra (IR) and thermogravimetric analyses (TGA) of these compounds were also studied.

  16. Plastic shaping of aqueous alumina suspensions with saccharides and dicarboxylic acids

    SciTech Connect

    Goel, H.; Schilling, C.H.; Biner, S.B.

    1996-06-01

    Traditional methods for the shape-forming of engineering ceramics entail plastic deformation of powder slurries containing hazardous organic liquids as suspending media. Replacing these organics with aqueous media requires the development of environmentally-benign, water-soluble additives which serve as plasticizers and binders. Fundamental studies were performed with aqueous suspensions of colloidal {alpha}-Al{sub 2}O{sub 3} to evaluate the role of sucrose, maltodextrin, and oxalic acid on viscosity, sedimentation and filtration characteristics, plastic flow behavior of filter cakes, and sinterability. Maltodextrin and oxalic acid systems exhibited superior results, including filtration to high packing-densities and clay-like plasticity with minimal cracking.

  17. Pretreatment of solid carbonaceous material with dicarboxylic aromatic acids to prevent scale formation

    DOEpatents

    Brunson, Roy J.

    1982-01-01

    Scale formation during the liquefaction of lower ranking coals and similar carbonaceous materials is significantly reduced and/or prevented by pretreatment with a pretreating agent selected from the group consisting of phthalic acid, phthalic anhydride, pyromellitic acid and pyromellitic anhydride. The pretreatment is believed to convert the scale-forming components to the corresponding phthalate and/or pyromellitate prior to liquefaction. The pretreatment is accomplished at a total pressure within the range from about 1 to about 2 atmospheres. Temperature during pretreatment will generally be within the range from about 5.degree. to about 80.degree. C.

  18. Concentrations of higher dicarboxylic acids C5-C13 in fresh snow samples collected at the High Alpine Research Station Jungfraujoch during CLACE 5 and 6

    NASA Astrophysics Data System (ADS)

    Winterhalter, R.; Kippenberger, M.; Williams, J.; Fries, E.; Sieg, K.; Moortgat, G. K.

    2009-03-01

    Samples of freshly fallen snow were collected at the high alpine research station Jungfraujoch (Switzerland) in February and March 2006 and 2007, during the Cloud and Aerosol Characterization Experiments (CLACE) 5 and 6. In this study a new technique has been developed and demonstrated for the measurement of organic acids in fresh snow. The melted snow samples were subjected to solid phase extraction and resulting solutions analysed for organic acids by HPLC-MS-TOF using negative electrospray ionization. A series of linear dicarboxylic acids from C5 to C13 and phthalic acid, were identified and quantified. In several samples the biogenic acid pinonic acid was also observed. In fresh snow the median concentration of the most abundant acid, adipic acid, was 0.69 μg L-1 in 2006 and 0.70 μg L-1 in 2007. Glutaric acid was the second most abundant dicarboxylic acid found with median values of 0.46 μg L-1 in 2006 and 0.61 μg L-1 in 2007, while the aromatic acid phthalic acid showed a median concentration of 0.34 μg L-1 in 2006 and 0.45 μg L-1 in 2007. The concentrations in the samples from various snowfall events varied significantly, and were found to be dependent on the back trajectory of the air mass arriving at Jungfraujoch. Air masses of marine origin showed the lowest concentrations of acids whereas the highest concentrations were measured when the air mass was strongly influenced by boundary layer air.

  19. Concentrations of higher dicarboxylic acids C5-C13 in fresh snow samples collected at the High Alpine Research Station Jungfraujoch during CLACE 5 and 6

    NASA Astrophysics Data System (ADS)

    Winterhalter, R.; Kippenberger, M.; Williams, J.; Fries, E.; Sieg, K.; Moortgat, G. K.

    2008-10-01

    Samples of freshly fallen snow were collected at the high alpine research station Jungfraujoch (Switzerland) in February and March 2006 and 2007, during the Cloud and Aerosol Characterization Experiments (CLACE) 5 and 6. In this study a new technique has been developed and demonstrated for the measurement of organic acids in fresh snow. The melted snow samples were subjected to solid phase extraction and resulting solution analysed for organic acids by HPLC-MS-TOF using negative electrospray ionization. A series of linear dicarboxylic acids from C5 to C13 and phthalic acid, were identified and quantified. In several samples the biogenic acid pinonic acid was also observed. In fresh snow the median concentration of the most abundant acid, adipic acid, was 0.69 μg L-1 in 2006 and 0.70 μg L-1 in 2007. Glutaric acid was the second most abundant dicarboxylic acid found with median values of 0.46 μg L-1 in 2006 and 0.61 μg L-1 in 2007, while the aromatic acid phthalic acid showed a median concentration of 0.34 μg L-1 in 2006 and 0.45 μg L-1 in 2007. The concentrations in the samples from various snowfall events varied significantly, and were found to be dependent on the back trajectory of the air mass arriving at Jungfraujoch. Air masses of marine origin showed the lowest concentrations of acids whereas the highest concentrations were measured when the air mass was strongly influenced by boundary layer air.

  20. Effects of the dicarboxylic acids malate and fumarate on E. coli O157:H7 and Salmonella Typhimurium populations in pure culture and mixed ruminal culture in in vitro fermentations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dicarboxylic acids malate and fumarate increase ruminal pH, reduce methane production, increase propionate and total VFA production, and reduce lactic acid accumulation in a manner similar to ionophores. The mechanism by which these acids effect the ruminal environment is reported to be through...

  1. Biotransformation of 5-hydroxy-methylfurfural into 2,5-furan-dicarboxylic acid by bacterial isolate using thermal acid algal hydrolysate.

    PubMed

    Yang, Chu-Fang; Huang, Ci-Ruei

    2016-08-01

    Thermal acid hydrolysis is often used to deal with lignocellulosic biomasses, but 5-hydroxy-methylfurfural (5-HMF) formed during hydrolysis deeply influences downstream fermentation. 2,5-Furan-dicarboxylic acid (FDCA), which is in the list of future important biomass platform molecules can be obtained using 5-HMF biotransformation. Based on the connection between 5-HMF removal in acid hydrolysate and FDCA production, the optimum thermal acid hydrolysis condition for macroalgae Chaetomorpha linum was established. Potential microbes capable of transforming 5-HMF into FDCA were isolated and characterized under various parameters and inoculated into algal hydrolysate to perform 5-HMF biotransformation. The optimum hydrolysis condition was to apply 0.5M HCl to treat 3% algal biomass under 121°C for 15min. Isolated Burkholderia cepacia H-2 could transform 2000mg/L 5-HMF at the initial pH of 7 at 28°C and 1276mg/L FDCA was received. Strain B. cepacia H-2 was suitable for treating the algal hydrolysate without dilution, receiving 989.5mg/L FDCA. PMID:27151683

  2. Cyclohexane-1,2-dicarboxylic acid diisononyl ester and metabolite effects on rat epididymal stromal vascular fraction differentiation of adipose tissue

    SciTech Connect

    Campioli, Enrico; Duong, Tam B.; Deschamps, François; Papadopoulos, Vassilios

    2015-07-15

    Plastics are generally mixed with additives like plasticizers to enhance their flexibility, pliability, and elasticity proprieties. Plasticizers are easily released into the environment and are absorbed mainly through ingestion, dermal contact, and inhalation. One of the main classes of plasticizers, phthalates, has been associated with endocrine and reproductive diseases. In 2002, 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) was introduced in the market for use in plastic materials and articles intended to come into contact with food, and it received final approval from the European Food Safety Authority in 2006. At present, there is limited knowledge about the safety and potential metabolic and endocrine-disrupting properties of DINCH and its metabolites. The purpose of this study was to evaluate the biological effects of DINCH and its active metabolites, cyclohexane-1,2-dicarboxylic acid (CHDA) and cyclohexane-1,2-dicarboxylic acid mono isononyl ester (MINCH), on rat primary stromal vascular fraction (SVF) of adipose tissue. DINCH and its metabolite, CHDA, were not able to directly affect SVF differentiation. However, exposure of SVF to 50 μM and 100 μM concentrations of MINCH affected the expression of Cebpa and Fabp4, thus inducing SVF preadipocytes to accumulate lipids and fully differentiate into mature adipocytes. The effect of MINCH was blocked by the specific peroxisome proliferator-activated receptor (PPAR)-α antagonist, GW6471. Taken together, these results suggest that MINCH is a potent PPAR-α agonist and a metabolic disruptor, capable of inducing SVF preadipocyte differentiation, that may interfere with the endocrine system in mammals. - Highlights: • DINCH and CHDA did not affect the adipogenesis of the SVF. • MINCH affected the adipogenesis of the SVF. • MINCH effect was blocked by the specific PPAR-α antagonist GW6471. • MINCH exerted a similar effect as MEHP on SVF adipogenesis. • DINCH/MINCH are potential metabolic

  3. Cyclohexane-1,2-dicarboxylic acid diisononyl ester and metabolite effects on rat epididymal stromal vascular fraction differentiation of adipose tissue.

    PubMed

    Campioli, Enrico; Duong, Tam B; Deschamps, François; Papadopoulos, Vassilios

    2015-07-01

    Plastics are generally mixed with additives like plasticizers to enhance their flexibility, pliability, and elasticity proprieties. Plasticizers are easily released into the environment and are absorbed mainly through ingestion, dermal contact, and inhalation. One of the main classes of plasticizers, phthalates, has been associated with endocrine and reproductive diseases. In 2002, 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) was introduced in the market for use in plastic materials and articles intended to come into contact with food, and it received final approval from the European Food Safety Authority in 2006. At present, there is limited knowledge about the safety and potential metabolic and endocrine-disrupting properties of DINCH and its metabolites. The purpose of this study was to evaluate the biological effects of DINCH and its active metabolites, cyclohexane-1,2-dicarboxylic acid (CHDA) and cyclohexane-1,2-dicarboxylic acid mono isononyl ester (MINCH), on rat primary stromal vascular fraction (SVF) of adipose tissue. DINCH and its metabolite, CHDA, were not able to directly affect SVF differentiation. However, exposure of SVF to 50 μM and 100 μM concentrations of MINCH affected the expression of Cebpa and Fabp4, thus inducing SVF preadipocytes to accumulate lipids and fully differentiate into mature adipocytes. The effect of MINCH was blocked by the specific peroxisome proliferator-activated receptor (PPAR)-α antagonist, GW6471. Taken together, these results suggest that MINCH is a potent PPAR-α agonist and a metabolic disruptor, capable of inducing SVF preadipocyte differentiation, that may interfere with the endocrine system in mammals.

  4. Solid-state NMR studies of theophylline co-crystals with dicarboxylic acids.

    PubMed

    Pindelska, Edyta; Sokal, Agnieszka; Szeleszczuk, Lukasz; Pisklak, Dariusz Maciej; Kolodziejski, Waclaw

    2014-11-01

    In this work, three polycrystalline materials containing co-crystals of theophylline with malonic, maleic, and glutaric acids were studied using (13)C, (15)N and (1)H solid-state NMR and FT-IR spectroscopy. The NMR assignments were supported by gauge including projector augmented waves (GIPAW) calculations of chemical shielding, performed using X-ray determined geometry. The experimental (13)C cross polarization/magic angle spinning (CP/MAS) NMR results and the calculated isotropic chemical shifts were in excellent agreement. A rapid and convenient method for theophylline co-crystals crystal structure analysis has been proposed for co-crystals, which are potentially new APIs.

  5. Mutations of fumarase that distinguish between the active site and a nearby dicarboxylic acid binding site.

    PubMed Central

    Weaver, T.; Lees, M.; Banaszak, L.

    1997-01-01

    Two mutant forms of fumarase C from E. coli have been made using PCR and recombinant DNA. The recombinant form of the protein included a histidine arm on the C-terminal facilitating purification. Based on earlier studies, two different carboxylic acid binding sites, labeled A- and B-, were observed in crystal structures of the wild type and inhibited forms of the enzyme. A histidine at each of the sites was mutated to an asparagine. H188N at the A-site resulted in a large decrease in specific activity, while the H129N mutation at the B-site had essentially no effect. From the results, we conclude that the A-site is indeed the active site, and a dual role for H188 as a potential catalytic base is proposed. Crystal structures of the two mutant proteins produced some unexpected results. Both mutations reduced the affinity for the carboxylic acids at their respective sites. The H129N mutant should be particularly useful in future kinetic studies because it sterically blocks the B-site with the carboxyamide of asparagine assuming the position of the ligand's carboxylate. In the H188N mutation at the active site, the new asparagine side chain still interacts with an active site water that appears to have moved slightly as a result of the mutation. PMID:9098893

  6. Two new Zn(II) coordination polymers based on mixed pipemidic acid and flexible aromatic dicarboxylic acid ligands: Syntheses, crystal structures and luminescent properties

    NASA Astrophysics Data System (ADS)

    Jia, Yanxia; Zhou, Pingping

    2016-09-01

    Two new Zn(II) coordination polymers, namely [Zn(4,4‧-sdb) (HPPA)]n (1) and [Zn(2,2‧-bpdc)0.5(PPA)]n (2) (4,4‧-H2sdb = 4,4‧-sulfonyldibenzoate, 2,2‧-H2bpdc = 2,2‧-biphenyldicarboxylic acid, HPPA = pipemidic acid) were successfully obtained under hydrothermal conditions. These two compounds were further characterized by single-crystal X-ray diffraction analyses, elemental analyses, powder X-ray diffraction (PXRD) analyses and IR spectra. Compound 1 features a 1D chain structure, which further extended into a 3D supramolecular framework via intermolecular hydrogen bonds and weak van der Waals interactions, and compound 2 features a 3D framework with 6-connected α-Po-type topology. The structural regulation for these two compounds was successfully achieved by changing the flexible aromatic dicarboxylic acid ligand. Moreover, the thermal stabilities and luminescent properties for these two compounds were also investigated.

  7. Engineering Escherichia coli for Conversion of Glucose to Medium-Chain ω-Hydroxy Fatty Acids and α,ω-Dicarboxylic Acids.

    PubMed

    Bowen, Christopher H; Bonin, Jeff; Kogler, Anna; Barba-Ostria, Carlos; Zhang, Fuzhong

    2016-03-18

    In search of sustainable approaches to plastics production, many efforts have been made to engineer microbial conversions of renewable feedstock to short-chain (C2-C8) bifunctional polymer precursors (e.g., succinic acid, cadaverine, 1,4-butanediol). Less attention has been given to medium-chain (C12-C14) monomers such as ω-hydroxy fatty acids (ω-OHFAs) and α,ω-dicarboxylic acids (α,ω-DCAs), which are precursors to high performance polyesters and polyamides. Here we engineer a complete microbial conversion of glucose to C12 and C14 ω-OHFAs and α,ω-DCAs, with precise control of product chain length. Using an expanded bioinformatics approach, we screen a wide range of enzymes across phyla to identify combinations that yield complete conversion of intermediates to product α,ω-DCAs. Finally, through optimization of culture conditions, we enhance production titer of C12 α,ω-DCA to nearly 600 mg/L. Our results indicate potential for this microbial factory to enable commercially relevant, renewable production of C12 α,ω-DCA-a valuable precursor to the high-performance plastic, nylon-6,12. PMID:26669968

  8. Production of Long-Chain α,ω-Dicarboxylic Acids by Engineered Escherichia coli from Renewable Fatty Acids and Plant Oils.

    PubMed

    Sathesh-Prabu, Chandran; Lee, Sung Kuk

    2015-09-23

    Long-chain α,ω-dicarboxylic acids (LDCAs, ≥ C12) are widely used as a raw material for preparing various commodities and polymers. In this study, a CYP450-monooxygenase-mediated ω-oxidation pathway system with high ω-regioselectivity was heterologously expressed in Escherichia coli to produce DCAs from fatty acids. The resulting engineered E. coli produced a maximum of 41 mg/L of C12 DCA and 163 mg/L of C14 DCA from fatty acids (1 g/L), following 20 h of whole cell biotransformation. Addition of a heme precursor and the hydroxyl radical scavenger, thiourea, increased product concentration (159 mg/L of C12 DCA and 410 mg/L of C14 DCA) in a shorter culture duration than that of the corresponding controls. DCAs of various chain lengths were synthesized from coconut oil hydrolysate using the engineered E. coli. This novel synthetic biocatalytic system could be applied to produce high value DCAs in a cost-effective manner from renewable plant oils. PMID:26359801

  9. Ion-Exclusion High-Performance Liquid Chromatography of Aliphatic Organic Acids Using a Surfactant-Modified C18 Column.

    PubMed

    Fasciano, Jennifer M; Mansour, Fotouh R; Danielson, Neil D

    2016-07-01

    Ion exclusion chromatography (IELC) of short chain aliphatic carboxylic acids is normally done using a cation exchange column under standard HPLC conditions but not in the ultra-HPLC (UHPLC) mode. A novel IELC method for the separation of this class of carboxylic acids by either HPLC or UHPLC utilizing a C18 column dynamically modified with sodium dodecyl sulfate has been developed. The sample capacity is estimated to be near 10 mM for a 20 µL injection or 0.2 µmol using a 150 × 4.6 mm column. The optimum mobile phase determined for three standard mixtures of organic acids is 1.84 mM sulfuric acid at pH 2.43 and a flow rate of 0.6 mL/min. Under optimized conditions, a HPLC separation of four aliphatic carboxylic acids such as tartaric, malonic, lactic and acetic can be achieved in under 4 min and in <2 min in the UHPLC mode at 2.1 mL/min. A variety of fruit juice and soft drink samples are analyzed. Stability of the column as measured by the retention order of maleic and fumaric acid is estimated to be ∼4,000 column volumes using HPLC and 600 by UHPLC. Reproducible chromatograms are achieved over at least a 2-month period. This study shows that the utility of a C18 column can be easily extended when needed to IELC under either standard or UHPLC conditions. PMID:27006111

  10. Poly[diaqua(μ2-3-carboxypyrazine-2-carboxylato)(μ2-pyrazine-2,3-dicarboxylic acid)potassium(I)

    PubMed Central

    Tombul, Mustafa; Güven, Kutalmis; Svoboda, Ingrid

    2008-01-01

    The structural unit of the title compound, [K(C6H3N2O4)(C6H4N2O4)(H2O)2]n, consists of one potassium cation, one hydrogen pyrazine-2,3-dicarboxyl­ate anion, one pyrazine-2,3-dicarboxylic acid mol­ecule and two water mol­ecules; this is twice the asymmetric unit, since the potassium cation lies on an inversion centre. Each anion or acid mol­ecule is linked to two potassium cations, while the potassium cation has contacts to four symmetry-equivalent organic ligands, with two different coordination modes towards this cation. In addition, each potassium cation is coordinated by two water O atoms, raising the coordination number to eight. One of the carboxyl groups of the acid retains its H atom, which forms a hydrogen bond to a coordinated water mol­ecule. The other carboxyl group is deprotonated in half of the ligands and protonated in the other half, taking part in a strong O—H⋯O hydrogen bond disordered over an inversion centre. The stabilization of the crystal structure is further assisted by O—H⋯O and O—H⋯N hydrogen bonds in which water acts as the donor. PMID:21200587

  11. Dicarboxylic acids, ω-oxocarboxylic acids, α-dicarbonyls, WSOC, OC, EC, and inorganic ions in wintertime size-segregated aerosols from central India: Sources and formation processes.

    PubMed

    Deshmukh, Dhananjay K; Kawamura, Kimitaka; Deb, Manas K

    2016-10-01

    The size distributions of aerosols can provide evidences for their sources and formation processes in the atmosphere. Size-segregated aerosols (9-sizes) were collected in urban site (Raipur: 21.2°N and 82.3°E) in central India during winter of 2012-2013. The samples were analyzed for dicarboxylic acids (C2-C12), ω-oxocarboxylic acids (ωC2-ωC9), pyruvic acid and α-dicarbonyls (C2-C3) as well as elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC) and inorganic ions. Diacids showed a predominance of oxalic acid (C2) followed by succinic and azelaic acid whereas ω-oxoacids exhibited a predominance of glyoxylic acid and glyoxal was more abundant than methylglyoxal in all the sizes. Diacids, ω-oxoacids and α-dicarbonyls showed bimodal size distribution with peaks in fine and coarse modes. High correlations of fine mode diacids and related compounds with potassium and levoglucosan suggest that they were presumably due to a substantial contribution of primary emission from biomass burning and secondary production from biomass burning derived precursors. High correlations of C2 with higher carbon number diacids (C3-C9) suggest that they have similar sources and C2 may be produced via the decay of its higher homologous diacids in fine mode. Considerable portions of diacids and related compounds in coarse mode suggest that they were associated with mineral dust particles by their adsorption and photooxidation of anthropogenic and biogenic precursors via heterogeneous reaction on dust surface. This study demonstrates that biomass burning and dust particles are two major factors to control the size distribution of diacids and related compounds in the urban aerosols from central India. PMID:27414241

  12. Preparation, characterisation and study of in vitro biologically active azamacrocyclic Cu(II) dicarboxylate complexes

    NASA Astrophysics Data System (ADS)

    Antonijević-Nikolić, Mirjana; Antić-Stanković, Jelena; Tanasković, Sladjana B.; Korabik, Maria J.; Gojgić-Cvijović, Gordana; Vučković, Gordana

    2013-12-01

    New cationic Cu(II) complexes with N, N‧, N″, N″‧-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) and aliphatic dicarboxylic acids: pentanedioic (glutaric acid = glutH2), hexanedioic acid (adipic acid = adipH2) and decanedioic acid (sebacic acid = sebH2) of general formula [Cu4(L)(tpmc)2](ClO4)6·xH2O, L = glut, x = 2; L = adip, x = 7; L = seb, x = 6 were isolated. Their composition and charges are proposed based on elemental analyses and molar conductivity measurements. By the comparison of their UV-Vis, reflectance, FTIR and EPR spectral data, CV and SQUID magnetic measurements, with those for the complex with butanedioic acid (succinic acid = succH2) of known molecular structure and analysis of LC/MS spectra, geometry with two [Cu2tpmc]4+ units bridged by dicarboxylate dianion engaging all oxygens is proposed. Within units, Cu(II) ions are also bridged with N portion of cyclam ring. All four complexes were screened to in vitro antimicrobial and cytotoxic activity along with free primary and secondary ligands, Cu(II) salt and solvent controls. Detected antibacterial and cytotoxic activity for the complexes was enhanced in most cases than the corresponding controls.

  13. Size distributions of dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids in atmospheric aerosols from Tanzania, East Africa during wet and dry seasons

    NASA Astrophysics Data System (ADS)

    Mkoma, S. L.; Kawamura, K.

    2012-09-01

    Atmospheric aerosol samples of PM2.5 and PM10 were collected during the wet and dry seasons in 2011 from a rural site in Tanzania and analysed for water-soluble dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids using a gas chromatography (GC) and GC/mass spectrometry. Here we report the size distribution and sources of diacids and related compounds for wet and dry seasons. Oxalic acid (C2) was found as the most abundant diacid species followed by succinic and/or malonic acids whereas glyoxylic acid and glyoxal were the dominant ketoacids and α-dicarbonyls, respectively in both seasons in PM2.5 and PM10. Mean concentration of C2 in PM2.5 (121.5± 46.6 ng m-3) was lower in wet season than dry season (258.1± 69.5 ng m-3). Similarly, PM10 samples showed lower concentration of C2 (168.6 ± 42.4 ng m-3) in wet season than dry season (292.4± 164.8 ng m-3). Relative abundances of C2 in total diacids were 65.4% and 67.1% in PM2.5 and 64.6% and 63.9% in PM10 in the wet and dry seasons, respectively. Total concentrations of diacids (289-362 m-3), ketoacids (37.8-53.7ng m-3), and α-dicarbonyls (5.7-7.8 ng m-3) in Tanzania are higher to those reported at a rural background site in Nylsvley (South Africa) but comparable or lower to those reported from sites in Asia and Europe. Diacids and ketoacids were found to be present mainly in the fine fraction in both seasons (total α-dicarbonyls in the dry season), suggesting a production of organic aerosols from pyrogenic sources and photochemical oxidations. The averaged contributions of total diacid carbon to aerosol total carbon were 1.4% in PM2.5 and 2.1% in PM10 in wet season and 3.3% in PM2.5 and 3.9% in PM10 in dry season whereas those to water-soluble organic carbon were 2.2% and 4.7% inPM2.5 and 3.1% and 5.8% in PM10 during the wet and dry seasons, respectively. These ratios suggest an enhanced photochemical oxidation of organic precursors and heterogeneous reactions on aerosols under strong solar

  14. Water-soluble dicarboxylic acids and ω-oxocarboxylic acids in size-segregated aerosols over northern Japan during spring: sources and formation processes

    NASA Astrophysics Data System (ADS)

    Deshmukh, Dhananjay Kumar; Kawamura, Kimitaka; Kobayashi, Minoru; Gowda, Divyavani

    2016-04-01

    Seven sets (AF01-AF07) of size-segregated aerosol (12-sizes) samples were collected using a Micro-Orifice Uniform Deposit Impactor (MOUDI) in Sapporo, Japan during the spring of 2001 to understand the sources and atmospheric processes of water-soluble organic aerosols in the outflow region of Asian dusts. The samples were analyzed for dicarboxylic acids (C2-C12) and ω-oxocarboxylic acids as well as inorganic ions. The molecular distribution of diacids showed the predominance of oxalic acid (C2) followed by malonic and succinic acids whereas ω-oxoacids showed the predominance of glyoxylic acid (ωC2) in size-segregated aerosols. SO42- and NH4+ are enriched in submicron mode whereas NO3- and Ca2+ are in supermicron mode. Most of diacids and ω-oxoacids are enriched in supermicron mode in the samples (AF01-AF03) influenced by the long-range transport of mineral dusts whereas enhanced presence in submicron mode was observed in other sample sets. The strong correlations of C2 with Ca2+ (r = 0.95-0.99) and NO3- (r = 0.96-0.98) in supermicron mode in the samples AF01-AF03 suggest the adsorption or production of C2 diacid via heterogeneous reaction on the surface of mineral dust during long-range atmospheric transport. The preferential enrichment of diacids and ω-oxoacids in mineral dust has important implications for the solubility and cloud nucleation properties of the dominant fraction of water-soluble organic aerosols. This study demonstrates that biofuel and biomass burning and mineral dust originated in East Asia are two major factors to control the size distribution of diacids and related compounds over northern Japan.

  15. Stable carbon isotopic compositions of total carbon, dicarboxylic acids and glyoxylic acid in the tropical Indian aerosols: Implications for sources and photochemical processing of organic aerosols

    NASA Astrophysics Data System (ADS)

    Pavuluri, Chandra Mouli; Kawamura, Kimitaka; Swaminathan, T.; Tachibana, Eri

    2011-09-01

    The tropical Indian aerosols (PM10) collected on day- and nighttime bases in winter and summer, 2007 from Chennai (13.04°N; 80.17°E) were studied for stable carbon isotopic compositions (δ13C) of total carbon (TC), individual dicarboxylic acids (C2-C9) and glyoxylic acid (ωC2). δ13C values of TC ranged from -23.9‰ to -25.9‰ (-25.0 ± 0.6‰; n = 49). Oxalic (C2) (-17.1 ± 2.5‰), malonic (C3) (-20.8 ± 1.8‰), succinic (C4) (-22.5 ± 1.5‰) and adipic (C6) (-20.6 ± 4.1‰) acids and ωC2 acid (-22.4 ± 5.5‰) were found to be more enriched with 13C compared to TC. In contrast, suberic (C8) (-29.4 ± 1.8‰), phthalic (Ph) (-30.1 ± 3.5‰) and azelaic (C9) (-28.4 ± 5.8‰) acids showed smaller δ13C values than TC. Based on comparisons of δ13C values of TC in Chennai aerosols to those (-24.7 ± 2.2‰) found in unburned cow-dung samples collected from Chennai and isotopic signatures of the particles emitted from point sources, we found that biofuel/biomass burning are the major sources of carbonaceous aerosols in South and Southeast Asia. The decrease in δ13C values of C9 diacid by about 5‰ from winter to summer suggests that tropical plant emissions also significantly contribute to organic aerosol in this region. Significant increase in δ13C values from C4 to C2 diacids in Chennai aerosols could be attributed for their photochemical processing in the tropical atmosphere during long-range transport from source regions.

  16. Contamination of aluminium oxide surfaces in ambient air investigated by FTIR MSR and TOF SIMS. Chemisorption of aliphatic carboxylic acids

    NASA Astrophysics Data System (ADS)

    Sondag, A. H. M.; Raas, M. C.; Van Velzen, P. N. T.

    1989-03-01

    Contamination in ambient air of freshly evaporated aluminium surfaces covered with a thin layer of native oxide has been studied using Fourier transform infrared multiple specular reflectance (FTIR MSR) and time-of-flight secondary ion mass spectrometry (TOF SIMS). The FTIR MSR experiments yield vibrational spectra than can be attributed to short-chain aliphatic carboxylic acids. Some reference spectra have been measured by FTIR MSR spectroscopy of samples prepared by chemisorption of formic, acetic, lactic, butyric and palmitic acids on oxidized aluminium and (in some cases) silver surfaces. From these data the major contaminant has to be the acetate ion. Saturation of the spectral intensities is observed within an hour after exposure to air. The TOF SIMS spectra confirm the conclusion with respect to the acetate ion. Mass peaks belonging to the formate, lactate and some inorganic anions are present in the TOF SIMS spectra.

  17. Surface enhanced Raman scattering of 2,2‧-biphenyl dicarboxylic acid on silver surfaces: Structure and orientation upon adsorption

    NASA Astrophysics Data System (ADS)

    Eom, So Young; Lee, Yu Ran; Kwon, Chan Ho; Kim, Hong Lae

    2016-07-01

    The SERS spectrum of 2,2‧-biphenyl dicarboxylic acid (22-BPDC) adsorbed on Ag nanoparticles has been measured and the observed bands are identified and assigned referred to the ordinary Raman spectrum and to the previously measured SERS spectrum of 4,4‧-biphenyl dicarboxylic acid (44-BPDC). [J. Mol. Struct. 1050, 2013, 128] As in the case of 44-BPDC, quantum chemical density functional theory calculations have also been performed to figure out structures and to calculate vibrational wavenumbers and eigenvectors in 22-BPDC. The observed SERS spectra could successfully be simulated from the models for adsorption of 22-BPDC to Ag and three Ag atom clusters. As opposed to 44-BPDC adsorbed flat on the Ag surfaces through both the COO-Ag and phenyl π-electron-metal interactions, the two phenyl rings remain twisted in 22-BPDC upon adsorption on the Ag surfaces with less π-electron-metal interaction because of small space allowances for the two closely located carboxyl groups compared to 44-BPDC.

  18. Double D-π-A dye linked by 2,2'-bipyridine dicarboxylic acid: influence of para- and meta-substituted carboxyl anchoring group.

    PubMed

    Ganesan, Paramaguru; Chandiran, Aravind Kumar; Gao, Peng; Rajalingam, Renganathan; Grätzel, Michael; Nazeeruddin, Mohammad Khaja

    2015-04-01

    Starting from 2,2'-bipyridine dicarboxylic acid, two new (D-π-A)2 sensitizers, including m-DA with the carboxyl anchoring group substituted meta to the donor-bridge moiety and p-DA with a para-substituted anchoring group, were synthesized in order to evaluate the impact of the position of the anchoring group on the optical, electrochemical, and photovoltaic properties of dye-sensitized solar cells. p-DA exhibits red-shifted absorption behavior compared to m-DA, owing to the more efficiently extended π-conjugation with para substitution. Both m-DA and p-DA are adsorbed on the mesoporous TiO2 surface by using both of their carboxylic acid groups in a bianchoring mode, which is confirmed through attenuated total reflectance FTIR analysis. Red-shifted absorption of p-DA assists the achievement of a red-shifted incident photon-to-electron conversion efficiency and a higher short-circuit current density than m-DA. The photogenerated electron lifetime in TiO2 is also found to be higher for para substituted p-DA than the meta-substituted m-DA, which results in a higher open-circuit voltage. All of the results suggest that dicarboxyl-2,2'-bipyridine can be used as an acceptor for metal-free organic sensitizers. However, the anchoring segments should be adjusted to the favorable position of the corresponding donor-bridge moieties for better conjugation.

  19. Synthesis, characterization and biological activities of metal(II) dipicolinate complexes derived from pyridine-2,6-dicarboxylic acid and 2-(piperazin-1-yl)ethanol

    NASA Astrophysics Data System (ADS)

    Büyükkıdan, Nurgün; Yenikaya, Cengiz; İlkimen, Halil; Karahan, Ceyda; Darcan, Cihan; Korkmaz, Tülin; Süzen, Yasemin

    2015-12-01

    The new water-soluble and air stable compounds (H2ppz)[Co(dipic)2]·6H2O (1), (H2ppz)[Ni(dipic)2]·6H2O (2) and (H2ppz)[Zn(dipic)2]·6H2O (3) were prepared by the reaction of corresponding metal(II) acetates and a proton transfer salt, (H2ppz) (Hdipic)2, (4) of pyridine-2,6-dicarboxylic acid (H2dipic) and 2-(piperazin-1-yl)ethanol (ppz). The compounds 1-3 were characterized by elemental, IR, UV-vis. thermal analyses, magnetic measurement and single crystal X-ray diffraction studies. The molecular structures of the title compounds consist of one 1-(2-hydroxyethyl)piperazine-1,4-diium (H2ppz+2) cation, one bis(pyridine-2,6-dicarboxylate)metal(II) [M(dipic)2]2- anion, and six uncoordinated water molecules. In compounds 1-3 the metal ions coordinate to two oxygen and one nitrogen atoms of two pyridine-2,6-dicarboxylate molecules forming an octahedral environment. Antimicrobial activities against Gram (-) wild type (Escherichia coli and Pseudomonas aeruginosa), Gram (+) wild type (Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus and Bacillus subtilis) and clinical isolate (Morganella morganii, Proteus vulgaris and Enterobacter aeruginosa) were also studied. The results were reported, discussed and compared with the corresponding starting materials ((H2ppz) (Hdipic)2 (4), H2dipic and ppz). MIC (Minimal Inhibition Concentration) values of the newly synthesized compounds were determined as 4000 μg/ml (except B. subtilis and clinical isolate E. aeruginosa, >4000 μg/ml).

  20. Dimethyl and diethyl esters of 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carb-oxy-lic acid: a comparison.

    PubMed

    Alfonso, Montserrat; Stoeckli-Evans, Helen

    2016-02-01

    In dimethyl 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carboxyl-ate, C18H14N4O4, (I), and diethyl 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carboxyl-ate, C20H18N4O4, (II), the dimethyl and diethyl esters of 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carb-oxy-lic acid, the orientation of the two pyridine rings differ. In (I), pyridine ring B is inclined to pyrazine ring A by 44.8 (2)° and the pyridine and pyrazine N atoms are trans to one another, while pyridine ring C is inclined to the pyrazine ring by 50.3 (2)°, with the pyridine and pyrazine N atoms cis to one another. In compound (II), the diethyl ester, which possesses twofold rotation symmetry, the pyridine ring is inclined to the pyrazine ring by 40.7 (1)°, with the pyridine and pyrazine N atoms trans to one another. In the crystal of (I), mol-ecules are linked by C-H⋯N hydrogen bonds, forming chains along [001]. The chains are linked by C-H⋯π inter-actions, forming a three-dimensional structure. In the crystal of (II), mol-ecules are linked via C-H⋯O hydrogen bonds, forming a three-dimensional framework. There are C-H⋯π inter-actions present within the framework. PMID:26958396

  1. Dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, fatty acids and benzoic acid in PM2.5 aerosol collected during CAREBeijing-2007: an effect of traffic restriction on air quality

    NASA Astrophysics Data System (ADS)

    Ho, K. F.; Huang, R.-J.; Kawamura, K.; Tachibana, E.; Lee, S. C.; Ho, S. S. H.; Zhu, T.; Tian, L.

    2014-06-01

    Thirty water-soluble organic species, including dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, fatty acids, and benzoic acid were determined as well as organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC) in PM2.5 samples collected during the Campaign of Air Quality Research in Beijing 2007 (CAREBeijing-2007) in the urban and suburban areas of Beijing. The objective of this study is to identify the influence of traffic emissions and regional transport to the atmosphere in Beijing during summer. PM2.5 samples collected with or without traffic restriction in Beijing are selected to evaluate the effectiveness of local traffic restriction measure on air pollution reduction. The average concentrations of the total quantified bifunctional organic compounds (TQBOC), total fatty acids and benzoic acid during the entire sampling period were 1184 ± 241 ng m-3, 597 ± 159 ng m-3 and 1496 ± 511ng m-3 in PKU, and 1050 ± 303 ng m-3, 475 ± 114 ng m-3 and 1278 ± 372 ng m-3 in Yufa. Oxalic acid (C2) was found as the most abundant dicarboxylic acid at PKU and Yufa, followed by phthalic acid (Ph). A strong even carbon number predominance with the highest level at palmitic acid (C16:0), followed by stearic acid (C18:0) was found for fatty acids. According to the back trajectories modeling results, the air masses were found to originate mainly from northeast, passing over southeast or south of Beijing (heavily populated, urbanized and industrialized areas), during heavier pollution events, whereas they are mainly from north or northwest sector (mountain areas without serious anthropogenic pollution sources) during cleaner events. The data with wind only from the same sector (minimizing the difference from regional contribution) but with and without traffic restriction in Beijing were analyzed to evaluate the effectiveness of local traffic restriction measure on the reduction of local air pollution in Beijing. The results suggested that the

  2. Dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, fatty acids and benzoic acid in PM2.5 aerosol collected during CAREBeijing-2007: an effect of traffic restriction on air quality

    NASA Astrophysics Data System (ADS)

    Ho, K. F.; Huang, R.-J.; Kawamura, K.; Tachibana, E.; Lee, S. C.; Ho, S. S. H.; Zhu, T.; Tian, L.

    2015-03-01

    Thirty water-soluble organic species, including dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, fatty acids and benzoic acid were determined as well as organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC) in PM2.5 samples collected during the Campaign of Air Quality Research in Beijing 2007 (CAREBeijing-2007) in the urban and suburban areas of Beijing. The objective of this study is to identify the influence of traffic emissions and regional transport to the atmosphere in Beijing during summer. PM2.5 samples collected with or without traffic restriction in Beijing are selected to evaluate the effectiveness of local traffic restriction measures on air pollution reduction. The average concentrations of the total quantified bifunctional organic compounds (TQBOCs), total fatty acids and benzoic acid during the entire sampling period were 1184±241, 597±159 and 1496±511 ng m-3 in Peking University (PKU), and 1050±303, 475±114 and 1278±372 ng m-3 in Yufa, Beijing. Oxalic acid (C2) was found as the most abundant dicarboxylic acid at PKU and Yufa followed by phthalic acid (Ph). A strong even carbon number predominance with the highest level at stearic acid (C18:0), followed by palmitic acid (C16:0) was found for fatty acids. According to the back trajectories modeling results, the air masses were found to originate mainly from the northeast, passing over the southeast or south of Beijing (heavily populated, urbanized and industrialized areas), during heavier pollution events, whereas they are mainly from the north or northwest sector (mountain areas without serious anthropogenic pollution sources) during less pollution events. The data with wind only from the same sector (minimizing the difference from regional contribution) but with and without traffic restriction in Beijing were analyzed to evaluate the effectiveness of local traffic restriction measures on the reduction of local air pollution in Beijing. The results suggested

  3. Synthesis of nanomagnetic fluids and their UV spectrophotometric response with aliphatic organic acids and 1st tier dendrimers

    NASA Astrophysics Data System (ADS)

    Pandya, Shivani R.; Singh, Man

    2016-04-01

    Synthesis of Magnetic nanoparticles were made using coprecipitation method on mixing Fe+3 and Fe+2 in 2:1 ratio with aqueous 8M NaOH which on heating at 90°C for 2 h has yielded 85% magnetic (Fe3O4) nanoparticles (MNPs), characterized by XRD, VSM, SEM, and HR-TEM. The formic acid (FA), oxalic acid (OA) and citric acid (CA), the series of aliphatic organic acids along with Trimesoyl 1, 3, 5 tridimethyl malonate (TTDMM), trimesoyl 1, 3, 5 tridiethyl malonate (TTDEM), trimesoyl 1, 3, 5 tridipropyl malonate (TTDPM), trimesoyl 1, 3, 5 tridibutyl malonate (TTDBM) and trimesoyl 1, 3, 5 tridihexyl malonate (TTDHM) 1st tier dendrimers were used separately for preparing nanomagnetic fluid. From 25 to 150 µM MNPs at an interval of 25 µM were dispersed in 150 µM of acids and dendrimers separately with DMSO. UV-VIS spectrophotometry showed a maximum MNPs dispersion with TTDMM against others and found to be most stable nanomagnetic fluid on account of capping type mechanism of acids.

  4. C4-Dicarboxylate Utilization in Aerobic and Anaerobic Growth.

    PubMed

    Unden, Gottfried; Strecker, Alexander; Kleefeld, Alexandra; Kim, Ok Bin

    2016-06-01

    C4-dicarboxylates and the C4-dicarboxylic amino acid l-aspartate support aerobic and anaerobic growth of Escherichia coli and related bacteria. In aerobic growth, succinate, fumarate, D- and L-malate, L-aspartate, and L-tartrate are metabolized by the citric acid cycle and associated reactions. Because of the interruption of the citric acid cycle under anaerobic conditions, anaerobic metabolism of C4-dicarboxylates depends on fumarate reduction to succinate (fumarate respiration). In some related bacteria (e.g., Klebsiella), utilization of C4-dicarboxylates, such as tartrate, is independent of fumarate respiration and uses a Na+-dependent membrane-bound oxaloacetate decarboxylase. Uptake of the C4-dicarboxylates into the bacteria (and anaerobic export of succinate) is achieved under aerobic and anaerobic conditions by different sets of secondary transporters. Expression of the genes for C4-dicarboxylate metabolism is induced in the presence of external C4-dicarboxylates by the membrane-bound DcuS-DcuR two-component system. Noncommon C4-dicarboxylates like l-tartrate or D-malate are perceived by cytoplasmic one-component sensors/transcriptional regulators. This article describes the pathways of aerobic and anaerobic C4-dicarboxylate metabolism and their regulation. The citric acid cycle, fumarate respiration, and fumarate reductase are covered in other articles and discussed here only in the context of C4-dicarboxylate metabolism. Recent aspects of C4-dicarboxylate metabolism like transport, sensing, and regulation will be treated in more detail. This article is an updated version of an article published in 2004 in EcoSal Plus. The update includes new literature, but, in particular, the sections on the metabolism of noncommon C4-dicarboxylates and their regulation, on the DcuS-DcuR regulatory system, and on succinate production by engineered E. coli are largely revised or new.

  5. C4-Dicarboxylate Utilization in Aerobic and Anaerobic Growth.

    PubMed

    Unden, Gottfried; Strecker, Alexander; Kleefeld, Alexandra; Kim, Ok Bin

    2016-06-01

    C4-dicarboxylates and the C4-dicarboxylic amino acid l-aspartate support aerobic and anaerobic growth of Escherichia coli and related bacteria. In aerobic growth, succinate, fumarate, D- and L-malate, L-aspartate, and L-tartrate are metabolized by the citric acid cycle and associated reactions. Because of the interruption of the citric acid cycle under anaerobic conditions, anaerobic metabolism of C4-dicarboxylates depends on fumarate reduction to succinate (fumarate respiration). In some related bacteria (e.g., Klebsiella), utilization of C4-dicarboxylates, such as tartrate, is independent of fumarate respiration and uses a Na+-dependent membrane-bound oxaloacetate decarboxylase. Uptake of the C4-dicarboxylates into the bacteria (and anaerobic export of succinate) is achieved under aerobic and anaerobic conditions by different sets of secondary transporters. Expression of the genes for C4-dicarboxylate metabolism is induced in the presence of external C4-dicarboxylates by the membrane-bound DcuS-DcuR two-component system. Noncommon C4-dicarboxylates like l-tartrate or D-malate are perceived by cytoplasmic one-component sensors/transcriptional regulators. This article describes the pathways of aerobic and anaerobic C4-dicarboxylate metabolism and their regulation. The citric acid cycle, fumarate respiration, and fumarate reductase are covered in other articles and discussed here only in the context of C4-dicarboxylate metabolism. Recent aspects of C4-dicarboxylate metabolism like transport, sensing, and regulation will be treated in more detail. This article is an updated version of an article published in 2004 in EcoSal Plus. The update includes new literature, but, in particular, the sections on the metabolism of noncommon C4-dicarboxylates and their regulation, on the DcuS-DcuR regulatory system, and on succinate production by engineered E. coli are largely revised or new. PMID:27415771

  6. Syntheses, structures and fluorescence properties of cadmium coordination polymers with triangular 1,3-bis[2-(4‧-pyridyl)ethenyl]benzene and linear dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Liang, Rui; Yue, Fangfang; Wang, Yuting; Guo, Yongkang; Xuan, Xiaopeng

    2016-09-01

    Three new polymeric complexes [Cd3(1,3-BPEB)3(1,4-BDC)3·2H2O]n (1), [Cd2(1,3-BPEB)2(4,4‧-BPDC)2]n (2) and [Cd2(1,3-BPEB)2(4,4‧-STDC)2]n (3) (1,3-BPEB = 1,3-bis[2-(4‧-pyridyl)ethenyl]benzene, 1,4-BDC = 1,4-benzenedicarboxylic acid, 4,4‧-BPDC = 4,4‧-biphenyldicarboxylic acid and 4,4‧-STDC = 4,4‧-stilbenedicarboxylic acid) have been prepared by the solvothermal reaction of 1,3-BPEB, Cd(NO3)2·4H2O and dicarboxylic acids. Single-crystal X-ray diffraction reveals that these complexes have novel complicated structures. Complex 1 is a 3-D network structure by linking Cd atoms with 1,4-BDC and 1,3-BPEB ligands. Complex 2 shows a 3-D interpenetrating layered structure formed by three networks which derived from bridged Cd atoms with 4,4‧-BPDC and 1,3-BPEB ligands. Complex 3 has a fivefold interpenetrating 3-D coordination framework by linking Cd atoms with 4,4‧-STDC and 1,3-BPEB ligands. The dicarboxylic acids afford different coordination modes to bind Cd atoms in these three complexes. Additionally, these compounds were further characterized by PXRD, FT-IR spectroscopy and thermogravimetric (TG) analysis. Their fluorescence spectra were also determined and analyzed in the solid state at room temperature.

  7. Complexation behavior of trivalent actinides and lanthanides with 1,10-phenanthroline-2,9-dicarboxylic acid based ligands: insight from density functional theory.

    PubMed

    Manna, Debashree; Ghanty, Tapan K

    2012-08-21

    We have investigated the complexation behavior of preorganized 1,10-phenanthroline-2,9-dicarboxylic acid (PDA) based ligands with trivalent lanthanides and actinides using density functional theory with various GGA type exchange-correlation functionals and different basis sets. New ligands have been designed from PDA through functionalization with soft donor atoms such as sulfur, resulting in mono-thio-dicarboxylic acids (TCA/TCA1) and di-thio-dicarboxylic acid (THIO). It has been found that selectivity in terms of complexation energy of actinides over lanthanides is the maximum with TCA1 where the metal-ligand binding is through the O atoms. This unusual feature where a softer actinide metal ion is bonded strongly with hard donor oxygen atoms has been explained using the popular chemical concepts, viz., Pearson's Hard-Soft-Acid-Base (HSAB) principle and the frontier orbital theory of chemical reactivity as proposed by Fukui. Detailed analysis within the framework of the HSAB principle indicates that the presence of softer nitrogen atoms in the phenanthroline moiety (which also act as donors to the metal ion) has a profound influence in changing the soft nature of the actinide ion, which in turn binds with the hard oxygen atoms in a stronger way as compared to the valence isoelectronic lanthanide ion. Also, the trends in the variation of calculated values of the metal-ligand bond distances and the corresponding complex formation energies have been rationalized using the Fukui reactivity indices corresponding to the metal ions and the donor sites. All the calculations have also been done in the presence of solvent. The "intra-ligand synergistic effect" demonstrated here for PDA or TCA1 with soft and hard donor centers might be very important in designing new ligands for selective extraction of various metal ions in a competitive environment. However, for TCA and THIO ligands with only soft donor centers, "intra-ligand synergism" may not be very efficient although

  8. Copper(II)-lanthanide(III) coordination polymers constructed from pyridine-2,5-dicarboxylic acid: Preparation, crystal structure and photoluminescence

    SciTech Connect

    Xia Zhengqiang; Wei Qing; Chen Sanping; Feng Xinming; Xie Gang; Qiao Chengfang; Zhang Guochun; Gao Shengli

    2013-01-15

    A series of 3d-4f heterometallic coordination polymers, formulated as {l_brace} [Cu{sub 3}Ln{sub 2}(pydc){sub 6}(H{sub 2}O){sub 12}]{center_dot}4H{sub 2}O{r_brace} {sub n} [Ln=Tb (1), Eu (2), Dy (3), Ho (4), Lu (5)], {l_brace} [CuNd{sub 2}(pydc){sub 4}(H{sub 2}O){sub 3}]{center_dot}H{sub 2}O{r_brace} {sub n} (6) and {l_brace} [Cu{sub 3}Pr{sub 2}(pydc){sub 6}(H{sub 2}O){sub 13}]{center_dot}4H{sub 2}O{r_brace} {sub n} (7) (where H{sub 2}pydc=pyridine-2,5-dicarboxylic acid), have been hydrothermally prepared by reactions of H{sub 2}pydc ligand with lanthanide ions in the presence of Cu(II) ion. X-ray crystal structure analysis reveals that these compounds exhibit rich structural chemistry. 1-5 are isomorphous and present a two-dimensional network constructed from Ln{sub 2}Cu{sub 2}L{sub 2}(H{sub 2}O){sub 2} SBU rings and CuL{sub 2}(H{sub 2}O) building blocks. In 6, two-dimensional ladder-like layers based on Nd(III) belts and CuL{sub 2}O{sub 2} units are assembled by H{sub 2}pydc ligands into a three-dimensional open framework. Polymer 7 displays a two-dimensional wave-like layer structure containing two distinct ring units, in which a new coordination mode of the pydc{sup 2-} ligand is observed. The results indicate that the coordination flexibility of the pydc{sup 2-} ligand and lanthanide contraction effect play cooperative roles in the formation of coordination polymers with different polymeric architectures. Compounds 1-2 exhibit intense green and red luminescence emission characteristics of Tb(III) and Eu(III), respectively. Furthermore, elemental analyses (EA), infrared spectra (IR) and thermogravimetric analyses (TGA) of these compounds were also studied. - Graphical abstract: Seven 3d-4f heterometallic coordination polymers were synthesized by reactions of H{sub 2}pydc with lanthanide metal ions in the presence of Cu{sup 2+}, the effects of Cu{sup 2+} on the structures and photoluminescent properties of Ln-pydc{sup 2-} systems were investigated. Highlights

  9. Catalytic C-H bond activation at nanoscale Lewis acidic aluminium fluorides: H/D exchange reactions at aromatic and aliphatic hydrocarbons.

    PubMed

    Prechtl, Martin H G; Teltewskoi, Michael; Dimitrov, Anton; Kemnitz, Erhard; Braun, Thomas

    2011-12-16

    Nanoscopic amorphous Lewis acidic aluminium fluorides, such as aluminium chlorofluoride (ACF) and high-surface aluminium fluoride (HS-AlF(3)), are capable of activating C-H bonds of aliphatic hydrocarbons. H/D exchange reactions are catalysed under mild conditions (40 °C).

  10. Dual effects of aliphatic carboxylic acids on cresolase and catecholase reactions of mushroom tyrosinase.

    PubMed

    Gheibi, N; Saboury, A A; Haghbeen, K; Rajaei, F; Pahlevan, A A

    2009-10-01

    Catecholase and cresolase activities of mushroom tyrosinase (MT) were studied in presence of some n-alkyl carboxylic acid derivatives. Catecholase activity of MT achieved its optimal activity in presence of 1.0, 1.25, 2.0, 2.2 and 3.2 mM of pyruvic acid, acrylic acid, propanoic acid, 2-oxo-butanoic acid, and 2-oxo-octanoic acid, respectively. Contrarily, the cresolase activity of MT was inhibited by all type of the above acids. Propanoic acid caused an uncompetitive mode of inhibition (K(i)=0.14 mM), however, the pyruvic, acrylic, 2-oxo-butanoic and 2-oxo-octanoic acids showed a competitive manner of inhibition with the inhibition constants (K(i)) of 0.36, 0.6, 3.6 and 4.5 mM, respectively. So, it seems that, there is a physical difference in the docking of mono- and o-diphenols to the tyrosinase active site. This difference could be an essential determinant for the course of the catalytic cycle. Monophenols are proposed to bind only the oxyform of the tyrosinase. It is likely that the binding of acids occurs through their carboxylate group with one copper ion of the binuclear site. Thus, they could completely block the cresolase reaction, by preventing monophenol binding to the enzyme. From an allosteric point of view, n-alkyl acids may be involved in activation of MT catecholase reactions.

  11. Simultaneous and sensitive analysis of aliphatic carboxylic acids by ion-chromatography using on-line complexation with copper(II) ion.

    PubMed

    Kemmei, Tomoko; Kodama, Shuji; Yamamoto, Atsushi; Inoue, Yoshinori; Hayakawa, Kazuichi

    2015-01-01

    A new approach to ion chromatography is proposed to improve the UV detection of aliphatic carboxylic acids separated by anion-exchange chromatography. When copper(II) ion added to the mobile phase, it forms complexes with carboxylic acids that can be detected at 240 nm. The absorbance was found to increase with increasing copper(II) ion concentration. The retention times of α-hydroxy acids were also found to depend on the copper(II) ion concentration. Addition of acetonitrile to the mobile phase improved the separation of aliphatic carboxylic acids. The detection limits of the examined carboxylic acids (formate, glycolate, acetate, lactate, propionate, 3-hydroxypropionate, n-butyrate, isobutyrate, n-valerate, isovalerate, n-caproate) calculated at S/N=3 ranged from 0.06 to 3 μM. The detector signal was linear over three orders of magnitude of carboxylic acid concentration. The proposed method was successfully applied to analyze aliphatic carboxylic acids in rainwater and bread.

  12. Limits of detections for the determination of mono- and dicarboxylic acids using gas and liquid chromatographic methods coupled with mass spectrometry

    PubMed Central

    Št’ávová, Jana; Beránek, Josef; Nelson, Eric P.; Diep, Bonnie A.; Kubátová, Alena

    2011-01-01

    The chromatographic separation and instrumental limits of detection (LODs) were obtained for a broad range of C1-C18 monocarboxylic (MCAs) and C2-C14 dicarboxylic acids (DCAs) employing either chemical derivatization followed by gas chromatography-mass spectrometry and flame ionization detection (GC-MS/FID) or direct analysis with liquid chromatography high resolution MS and tandem MS (LC-MS). Suitability, efficiency and stability of reaction products for several derivatization agents used for esterification (BF3/butanol), and trimethysilylation, including trimethylsilyl-N-N-dimethylcarbamate (TMSDMC) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) were evaluated. The lowest limits of detection for the majority of compounds below 10 pg (with the exception of acetic acid) were obtained for derivatization with BF3/butanol followed by GC-MS in the total ion current (TIC) mode. Further improvements were achieved when applying either selected ion monitoring (SIM), which decreased the LODs to 1–4 pg or a combination of SIM and TIC (SITI) (2–5 pg). GC-FID provided LODs comparable to those obtained by GC-MS TIC. Both trimethylsilylation (followed by GC-MS) and direct LC-MS/MS analysis yielded LODs of 5– 40 pg for most of the acids. For volatile acids the LODs were higher, e.g., 25 and 590 ng for TMSDMC and BSTFA derivatized formic acid, respectively whereas the LC-MS methods did not allow for the analysis of formic acid at all. PMID:21185238

  13. Structure and properties of Al-MIL-53-ADP, a breathing MOF based on the aliphatic linker molecule adipic acid.

    PubMed

    Reinsch, Helge; Pillai, Renjith S; Siegel, Renée; Senker, Jürgen; Lieb, Alexandra; Maurin, Guillaume; Stock, Norbert

    2016-03-14

    The new aluminium based metal-organic framework [Al(OH)(O2C-C4H8-CO2)]·H2O denoted as Al-MIL-53-ADP-lp (lp stands for large pore) was synthesised under solvothermal conditions. This solid is an analogue of the archetypical aluminium terephthalate Al-MIL-53 based on the aliphatic single-chain linker molecule adipic acid (H2ADP, hexanedioic acid). In contrast to its aromatic counterparts, Al-MIL-53-ADP exhibits a structural breathing behaviour solely upon dehydration/rehydration. The crystal structure of the anhydrous compound denoted as Al-MIL-53-ADP-np (np stands for narrow pore) was determined by a combination of forcefield-based computations and Rietveld refinement of the powder X-ray diffraction data while the structure of the hydrated form Al-MIL-53-ADP-lp was derived computationally by a combination of force field based methods and Density Functional Theory calculations. Both structures were further supported by (1)H, (13)C and (27)Al high-resolution NMR MAS 1D data coupled again with simulations. Al-MIL-53-ADP was further characterised by means of vibrational spectroscopy, elemental analysis, thermogravimetry and water vapour sorption. PMID:26498663

  14. Aliphatic Hydrocarbons and Fatty Acids of Some Marine and Freshwater Microorganisms

    PubMed Central

    Oró, J.; Tornabene, T. G.; Nooner, D. W.; Gelpi, E.

    1967-01-01

    Gas chromatography and combined gas chromatography-mass spectrometry have been used to study the fatty acids and hydrocarbons of a bacterium from the Pacific Ocean, Vibrio marinus, a freshwater blue-green alga, Anacystis nidulans, and algal mat communities from the Gulf of Mexico. Both types of microorganisms (bacteria and algae) showed relatively simple hydrocarbon and fatty acid patterns, the hydrocarbons predominating in the region of C-17 and the fatty acids in the range of C-14 to C-18. The patterns of V. marinus were more comparable to those of the algal populations than to patterns reported for other bacteria. An incomplete correlation between fatty acids and hydrocarbons in both types of organisms was observed, making it difficult to accept the concept that the biosynthesis of hydrocarbons follows a simple fatty acid decarboxylation process. PMID:6025301

  15. Synthesis and characterization of zinc-organic frameworks with 1,4-benzenedicarboxylic acid and azobenzene-4,4'-dicarboxylic acid

    NASA Astrophysics Data System (ADS)

    Nguyen, Van Hung; Phuong Thuy Nguyen, Ngoc; Tuyet Nhung Nguyen, Thi; Thanh Thuy Le, Thi; Nghiem Le, Van; Chinh Nguyen, Quoc; Quang Ton, That; Hoang Nguyen, Thai; Phuong Thoa Nguyen, Thi

    2011-06-01

    The solvothermal reactions of 1,4-bezenedicarboxylic acid (H2BDC) or azobenzene-4,4'-dicarboxylic acid (H2ABD) with zinc ions/clusters lead to the formation of four crystalline materials. All of these compounds were characterized by x-ray diffraction, optical microscopy, thermo-gravimetric analysis and nitrogen adsorption. Block-shaped crystals (BZ1) with various shapes and sizes were obtained at H2BDC:Zn mole ratio of 1:1 and H2BDC concentration of 0.1 M. At more dilute H2BDC concentration of 0.01 M and H2BDC:Zn mole ratio of 1 : 4, the reaction product was cubic crystals (BZ2) with a size of 250 μm. In the H2ABD system, flat-plate-like crystals (AZ1) were obtained at H2ABD:Zn mole ratio of 1 : 1 and H2ABD concentration of 0.01 M. Meanwhile, thick-block-like crystals (AZ2) were formed at the same H2ABD:Zn mole ratio but at 0.004 M H2ABD. The Langmuir surface area (SLang) of the materials was remarkable, enhanced by diluting the reaction solution. For the compounds synthesized in N,N'-dimethylformamide (DMF), SLang increased from 304.6 m2 g‑1 for BZ1 to 2631 m2 g‑1 for BZ2 and from 475.8 m2 g‑1 for AZ1 to 3428 m2 g‑1 for AZ2. Meanwhile, BZ2 synthesized in N,N'-diethylformamide (BZ2/DEF) got the highest SLang of 4330 m2 g‑1. Both AZ2 and BZ2 materials were stable up to 400 °C.

  16. Highly Preorganized Ligand 1,10-Phenanthroline-2,9-dicarboxylic Acid for the Selective Recovery of Uranium from Seawater in the Presence of Competing Vanadium Species

    DOE PAGES

    Lashley, Mark A.; Ivanov, Alexander S.; Bryantsev, Vyacheslav S.; Dai, Sheng; Hancock, Robert D.

    2016-09-30

    Studies of the complexation of new promising ligands with uranyl (UO22+) and other seawater cations can aid the development of more efficient, selective, and robust sorbents for the recovery of uranium from seawater. Here, we propose that the ligand design principles based on structural preorganization can be successfully applied to obtain a dramatic enhancement in UO22+ ion binding affinity and selectivity. This concept is exemplified through the investigation of the com-plexes of UO22+, VO2+, and VO2+ with the highly preorganized ligand PDA (1,10-phenanthroline-2,9-dicarboxylic acid) using a combination of fluores-cence and absorbance techniques, along with den-sity functional theory (DFT) calculations. Moreover,more » the measured stability constant value, log K1, of 16.5 for the UO22+/PDA complex is very high compared to uranyl complexes with other dicarboxylic ligands. Moreover, PDA exhibits strong selectivity for uranyl over vanadium ions, since the determined sta-bility constant values of the PDA complexes of the vanadium ions are quite low (V(IV) log K1 = 7.4, V(V) = 7.3). Finally, the structures of the corresponding UO22+, VO2+, and VO2+ complexes with PDA were identified by systematic DFT calculations, and helped to interpret the stronger binding affinity for uranium over the vanadium ions. Due to its high chemical stability, selectivity, and structural preor-ganization for UO22+ complexation, PDA is a very promising candidate that can be potentially used in the development of novel adsorbent materials for the selective extraction of uranium from sea-water.« less

  17. Removal of aliphatic amino acids by hybrid organic inorganic layered compounds

    NASA Astrophysics Data System (ADS)

    Silverio, Fabiano; dos Reis, Márcio José; Tronto, Jairo; Valim, João Barros

    2007-04-01

    Amino acids have been extensively used in several processes of the pharmaceutical and food industries. Treatments for the recovery and reuse of the wastewaters generated from these processes are few and little known. This work aims at studying the influence of variables like temperature, pH and ionic strength on the adsorption of the amino acids Asp and Glu, contained in aqueous solutions, on layered double hydroxides of the Mg-Al-CO 3-LDH system. The adsorption experiments were performed at two different temperatures (298 and 310 K), two different pH values (7.0 and 10.0), and two ionic strength conditions (with or without the addition of NaCl). The adsorption isotherms exhibited similar profiles under the various conditions studied: an increase in temperature as well as an increase in the pH value decreased the amount of adsorbed amino acid while an increase in the ionic strength increased Asp and Glu adsorption. The PXRD analysis showed that the diffractograms obtained before and after the adsorption of amino acids have a similar pattern. The FT-IR spectra of the adsorbed material presented specific bands, which are related to the amino acids. The concentration range varied up to the anion solubility product and the extraction rate lay between 2.7 and 23.4% at higher equilibrium concentrations, showing that Mg-Al-CO 3-LDH is efficient at removing the amino acids from the aqueous medium.

  18. Generation of aliphatic acid anions and carbon dioxide by hydrous pyrolysis of crude oils

    USGS Publications Warehouse

    Kharaka, Y.K.; Lundegard, P.D.; Ambats, G.; Evans, William C.; Bischoff, J.L.

    1993-01-01

    Two crude oils with relatively high (0.60 wt%) and low (0.18 wt%) oxygen contents were heated in the presence of water in gold-plated reactors at 300??C for 2348 h. The high-oxygen oil was also heated at 200??C for 5711 h. The compositions of aqueous organic acid anions of the oils and of the headspace gases were monitored inn order to investigate the distribution of organic acids that can be generated from liquid petroleum. The oil with higher oxygen content generated about five times as much organic anions as the other oil. The dominant organic anions produced were acetate, propionate and butyrate. Small amounts of formate, succinate, methyl succinate and oxalate were also produced. The dominant oxygen-containing product was CO2, as has been observed in similar studies on the hydrous pyrolysis of kerogen. These results indicate that a significant portion (10-30%) of organic acid anions reported i be generated by thermal alteration of oils in reservoir rocks. The bulk of organic acid anions present in formation waters, however, is most likely generated by thermal alteration of kerogen in source rocks. Kerogen is more abundant than oil in sedimentary basins and the relative yields of organic acid anions reported from the hydrous pyrolysis of kerogen are much higher than the yields obtained for the two oils. ?? 1993.

  19. Synthesis, characterization, crystal structure and solution studies of a novel proton transfer (charge transfer) complex of 2,2‧-dipyridylamine with 2,6-pyridine dicarboxylic acid

    NASA Astrophysics Data System (ADS)

    Ghasemi, Khaled; Rezvani, Ali Reza; Shokrollahi, Ardeshir; Zarghampour, Fereshteh; Moghimi, Abolghasem; García-Granda, Santiago; Mendoza-Meroño, Rafael

    2015-06-01

    Reaction between 2,2‧-dipyridylamine (DPA) and 2,6-pyridine dicarboxylic acid (dipicolinic acid, dipicH2), in water results in the formation of a proton transfer or charge transfer (CT) complex, (DPAH)+(dipicH)-·H2O, 1. The characterization was performed using 1H NMR and FTIR spectroscopy, elemental analysis and X-ray crystallography. The crystal system is triclinic with space group P1. The structural investigations exhibit that the hydrogen bonds and π-π stacking interactions stabilize the crystal structure of proton transfer complex. The protonation constants of 2,6-pyridine dicarboxylic acid, 2,2‧-dipyridylamine and the equilibrium constants for dipic-DPA (1:1) proton transfer system were calculated by potentiometric pH titration method using Hyperquad2008 program. The stoichiometries of the proton transfer species in solution was in agreement with the solid state result.

  20. Lipid bilayer permeation of aliphatic amine and carboxylic acid drugs: rates of insertion, translocation and dissociation from MD simulations.

    PubMed

    Oruç, Tuğçe; Küçük, Sami Emre; Sezer, Deniz

    2016-09-21

    Aliphatic amines (AAs) and carboxylic acids (CAs) constitute the two most commonly occurring chemical groups among orally active drugs [Manallack, et al., ChemMedChem, 2013, 8, 242]. Here, we aim to rationalize this observation in terms of molecular properties that are essential for drug bioavailability. To this end, the permeation of the AA drug dyclonine and the CA drug 4-phenylbutyrate through a lipid bilayer is studied with molecular dynamics (MD) simulations. Permeability coefficients for the neutral and ionized forms of these drugs are calculated using the inhomogeneous solubility-diffusion model. To draw conclusions about other AA and CA drugs, the permeability coefficient is expressed as a sum over contributions from drug insertion into, translocation across, and dissociation from the lipid bilayer. Simple but general expressions for each of these separate steps are obtained and validated against the MD simulations of dyclonine and phenylbutyrate. We conclude that the neutral forms of most AA and CA drugs have large permeability coefficients (>1 cm s(-1)), while their ionized forms ensure solubility in aqueous environments. Thus, a physicochemical rationale for the reported abundance of AAs and CAs among drugs is provided.

  1. Lipid bilayer permeation of aliphatic amine and carboxylic acid drugs: rates of insertion, translocation and dissociation from MD simulations.

    PubMed

    Oruç, Tuğçe; Küçük, Sami Emre; Sezer, Deniz

    2016-09-21

    Aliphatic amines (AAs) and carboxylic acids (CAs) constitute the two most commonly occurring chemical groups among orally active drugs [Manallack, et al., ChemMedChem, 2013, 8, 242]. Here, we aim to rationalize this observation in terms of molecular properties that are essential for drug bioavailability. To this end, the permeation of the AA drug dyclonine and the CA drug 4-phenylbutyrate through a lipid bilayer is studied with molecular dynamics (MD) simulations. Permeability coefficients for the neutral and ionized forms of these drugs are calculated using the inhomogeneous solubility-diffusion model. To draw conclusions about other AA and CA drugs, the permeability coefficient is expressed as a sum over contributions from drug insertion into, translocation across, and dissociation from the lipid bilayer. Simple but general expressions for each of these separate steps are obtained and validated against the MD simulations of dyclonine and phenylbutyrate. We conclude that the neutral forms of most AA and CA drugs have large permeability coefficients (>1 cm s(-1)), while their ionized forms ensure solubility in aqueous environments. Thus, a physicochemical rationale for the reported abundance of AAs and CAs among drugs is provided. PMID:27539552

  2. Low molecular weight dicarboxylic acids, ketoacids, and dicarbonyls in the fine particles from a roadway tunnel: possible secondary production from the precursors.

    PubMed

    Wang, Haobo; Kawamura, Kimitaka; Ho, K F; Lee, S C

    2006-10-15

    Low molecular weight dicarboxylic acids (DCAs), ketoacids, and alpha-dicarbonyls have been determined for the PM2.5 samples in a Hong Kong roadway tunnel, using a water extraction followed by a butyl ester and/or dibutyl acetal derivatization technique. For the most wintertime sampling runs, outlet and inlet concentrations of the quantified compounds were found to be quite similar (ca. 10% differences), leading to the conclusion that direct emissions of the organic compounds are insignificant from vehicles in hot-stabilized operations although vehicular emissions can provide important precursors to them. In contrast, a significant concentration increase of most compounds was observed at the outlet station compared to the inlet station in the summertime runs, which might be explained by the secondary production of aerosols in the tunnel. The organic compounds studied comprised a small fraction (<1%) of aerosol organic carbon (OC). In winter, their abundances relative to that of OC in outlet samples were found to be significantly less than those in inlet samples. On the basis of the summer data, apparent secondary production factors of the compounds were calculated, which indicate that adipic and m-phthalic acids can be favorably formed in the tunnel. However, like other DCAs, direct emissions of adipic, m-phthalic, and p-phthalic acids from automobiles are suggested to be insignificant.

  3. Bio-inspired nitrile hydration by peptidic ligands based on L-cysteine, L-methionine or L-penicillamine and pyridine-2,6-dicarboxylic acid.

    PubMed

    Byrne, Cillian; Houlihan, Kate M; Devi, Prarthana; Jensen, Paul; Rutledge, Peter J

    2014-01-01

    Nitrile hydratase (NHase, EC 4.2.1.84) is a metalloenzyme which catalyses the conversion of nitriles to amides. The high efficiency and broad substrate range of NHase have led to the successful application of this enzyme as a biocatalyst in the industrial syntheses of acrylamide and nicotinamide and in the bioremediation of nitrile waste. Crystal structures of both cobalt(III)- and iron(III)-dependent NHases reveal an unusual metal binding motif made up from six sequential amino acids and comprising two amide nitrogens from the peptide backbone and three cysteine-derived sulfur ligands, each at a different oxidation state (thiolate, sulfenate and sulfinate). Based on the active site geometry revealed by these crystal structures, we have designed a series of small-molecule ligands which integrate essential features of the NHase metal binding motif into a readily accessible peptide environment. We report the synthesis of ligands based on a pyridine-2,6-dicarboxylic acid scaffold and L-cysteine, L-S-methylcysteine, L-methionine or L-penicillamine. These ligands have been combined with cobalt(III) and iron(III) and tested as catalysts for biomimetic nitrile hydration. The highest levels of activity are observed with the L-penicillamine ligand which, in combination with cobalt(III), converts acetonitrile to acetamide at 1.25 turnovers and benzonitrile to benzamide at 1.20 turnovers.

  4. Identification of keto- and hydroxy-dicarboxylic acids in remote marine aerosols from the western North Pacific: GC and GC/TOF-MS measurements

    NASA Astrophysics Data System (ADS)

    Vani, D.; Kawamura, K.; Tachibana, E.; Boreddy, S. K. R.

    2015-12-01

    Dicarboxylic acids (diacids) are dominant components of organic aerosols in the atmosphere. They contribute significantly to the total aerosol mass and have a serious impacts on global climate changes. However, studies on keto- and hydroxy-diacids in marine aerosols are limited. Compare to diacids, keto- and hydroxy-diacids are more hygroscopic due to the additional polar groups (OH and CO) and, hence, acts as cloud condensation nuclei (CCN). Molecular characterization of these compounds provides insight into organic aerosols sources and transformation pathways. We collected marine aerosols from remote Chichijima Island in the western North Pacific from December 2010 to November 2011 and studied for water-soluble keto- and hydroxy-diacids. Carboxyl groups were derivatized to dibutyl esters with 14% boron trifluoride/n-butanol, whereas hydroxyl groups were derivatized to trimethylsilyl ethers using N,O-Bis (trimethylsilyl) trifluoroacetamide (BSTFA). After two-step derivatization, samples were injected to GC, GC/MS and GC/TOF-MS. In the GC chromatogram, we detected several new peaks after BSTFA derivatization of dibutyl ester fraction. Based on mass spectral interpretation, we found these peaks as homologues series of hydroxy-diacids and keto-diacids. Some of these hydroxy-diacids have been individually reported in literature in the laboratory photo-oxidation experiments and forest environments samples. But, there are no evidences to prove their sources and formation mechanism in the atmosphere. Here, we report for the first time homologous series of hydroxy-diacids (hC3di-hC6di) and keto-diacid (oxaloacetic acid, enol and keto forms) in remote marine atmosphere. Molecular distributions of hydroxy-diacids generally showed the predominance of malic acid followed by tartronic acid. Both hydroxy- and keto-diacids show significant positive correlation with oxalic acid and SO42-, suggesting that they are generated in the atmosphere and play an important role in the

  5. Reactions of charged phenyl radicals with aliphatic amino acids in the gas phase.

    PubMed

    Huang, Yiqun; Guler, Leo; Heidbrink, Jenny; Kenttämaa, Hilkka

    2005-03-23

    Gas-phase reactivity of five differently substituted positively charged phenyl radicals was examined toward six amino acids by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR). The reactivity of the radicals studied was determined by the electrophilicity of the radical, which can be characterized by the radical's electron affinity (EA). The larger the electron affinity of the radical, the higher the overall reaction rate. In addition to the expected H-atom abstraction, several unprecedented reaction pathways were observed, including NH2 abstraction, SH abstraction, and SCH3 abstraction. These reaction pathways dominate for the most electrophilic radicals, and they may not follow radical but rather nucleophilic addition-elimination mechanisms. Hydrogen abstraction from glycine was also investigated theoretically. The results indicate that hydrogen abstraction from alphaC of glycine is both kinetically and thermodynamically favored over the NH2 group. The ordering of transition state energies for hydrogen abstraction from the alphaC and NH2 groups was found to reflect the radicals' EA ordering.

  6. Transepithelial transport of aliphatic carboxylic acids studied in Madin Darby canine kidney (MDCK) cell monolayers.

    PubMed

    Cho, M J; Adson, A; Kezdy, F J

    1990-04-01

    Transport of 14C-labeled acetic, propionic (PA), butyric, valeric, heptanoic (HA), and octanoic (OA) acids across the Madin Darby canine kidney (MDCK) epithelial cell monolayer grown on a porous polycarbonate membrane was studied in Hanks' balanced salt solution (HBSS) at 37 degrees C in both apical-to-basolateral and basolateral-to-apical directions. At micromolar concentrations of solutes, metabolic decomposition was significant as evidenced by [14C]CO2 production during the OA transport. The apparent permeability (Pe) indicates that as lipophilicity increases, diffusion across the "unstirred" boundary layer becomes rate limiting. In support of this notion, transport of OA and HA was enhanced by agitation, showed an activation energy of 3.7 kcal/mol for OA, and resulted in identical Pe values for both transport directions. Analysis of Pe changes with varying alkyl chain length resulted in a delta G of -0.68 +/- 0.09 kcal/mol for -CH2-group transfer from an aqueous phase to the MDCK cells. When the intercellular tight junctions were opened by the divalent chelator EGTA in Ca2+/Mg2(+)-free HBSS, transport of the fluid-phase marker Lucifer yellow greatly increased because of paracellular leakage. PA transport also showed a significant increase, but OA transport was independent of EGTA. Although albumin also undergoes paracellular transport in the presence of EGTA and OA binds strongly to albumin, OA transport in EGTA solution was unchanged by albumin. These observations indicate that transmembrane transport is the major mechanism for lipophilic substances. The present study, together with earlier work on the transport of polar substances, shows that the MDCK cell monolayer is an excellent model of the transepithelial transport barrier.

  7. Transepithelial transport of aliphatic carboxylic acids studied in Madin Darby canine kidney (MDCK) cell monolayers

    SciTech Connect

    Cho, M.J.; Adson, A.; Kezdy, F.J. )

    1990-04-01

    Transport of 14C-labeled acetic, propionic (PA), butyric, valeric, heptanoic (HA), and octanoic (OA) acids across the Madin Darby canine kidney (MDCK) epithelial cell monolayer grown on a porous polycarbonate membrane was studied in Hanks' balanced salt solution (HBSS) at 37{degrees}C in both apical-to-basolateral and basolateral-to-apical directions. At micromolar concentrations of solutes, metabolic decomposition was significant as evidenced by (14C)CO2 production during the OA transport. The apparent permeability (Pe) indicates that as lipophilicity increases, diffusion across the unstirred boundary layer becomes rate limiting. In support of this notion, transport of OA and HA was enhanced by agitation, showed an activation energy of 3.7 kcal/mol for OA, and resulted in identical Pe values for both transport directions. Analysis of Pe changes with varying alkyl chain length resulted in a delta G of -0.68 +/- 0.09 kcal/mol for -CH2-group transfer from an aqueous phase to the MDCK cells. When the intercellular tight junctions were opened by the divalent chelator EGTA in Ca2+/Mg2(+)-free HBSS, transport of the fluid-phase marker Lucifer yellow greatly increased because of paracellular leakage. PA transport also showed a significant increase, but OA transport was independent of EGTA. Although albumin also undergoes paracellular transport in the presence of EGTA and OA binds strongly to albumin, OA transport in EGTA solution was unchanged by albumin. These observations indicate that transmembrane transport is the major mechanism for lipophilic substances. The present study, together with earlier work on the transport of polar substances, shows that the MDCK cell monolayer is an excellent model of the transepithelial transport barrier.

  8. Thermodynamic models of aqueous solutions containing inorganic electrolytes and dicarboxylic acids at 298.15 K. 2. Systems including dissociation equilibria.

    PubMed

    Clegg, Simon L; Seinfeld, John H

    2006-05-01

    Atmospheric aerosols contain a significant fraction of water-soluble organic compounds, including dicarboxylic acids. Pitzer activity coefficient models are developed, using a wide range of data at 298.15 K, for the following systems containing succinic acid (H(2)Succ) and/or succinate salts: [H(+), Li(+), Na(+), K(+), Rb(+), Cs(+)]Cl(-)-H(2)Succ-H(2)O, HNO(3)-H(2)Succ-H(2)O, H(+)-NH(4)(+)-HSucc(-)-Succ(2-)-NH(3)-H(2)Succ-H(2)O, NH(4)Cl-(NH(4))(2)Succ-H(2)O, H(+)-Na(+)-HSucc(-)-Succ(2-)-Cl(-)-H(2)Succ-H(2)O, NH(4)NO(3)-H(2)Succ-H(2)O, and H(2)SO(4)-H(2)Succ-H(2)O. The above compositions are given in terms of ions in the cases where acid dissociation was considered. Pitzer models were also developed for the following systems containing malonic acid (H(2)Malo): H(+)-Na(+)-HMalo(-)-Malo(2-)-Cl(-)-H(2)Malo-H(2)O, and H(2)Malo-H(2)SO(4)-H(2)O. The models are used to evaluate the extended Zdanovskii-Stokes-Robinson (ZSR) model proposed by Clegg and Seinfeld (J. Phys. Chem. A 2004, 108, 1008-1017) for calculating water and solute activities in solutions in which dissociation equilibria occur. The ZSR model yields satisfactory results only for systems that contain moderate to high concentrations of (nondissociating) supporting electrolyte. A practical modeling scheme is proposed for aqueous atmospheric aerosols containing both electrolytes and dissociating (organic) nonelectrolytes.

  9. Molecular distributions and stable carbon isotopic compositions of dicarboxylic acids and related compounds in aerosols from Sapporo, Japan: Implications for photochemical aging during long-range atmospheric transport

    NASA Astrophysics Data System (ADS)

    Aggarwal, Shankar G.; Kawamura, Kimitaka

    2008-07-01

    Molecular and stable carbon isotopic (δ13C value) compositions of dicarboxylic acids, ketoacids, and dicarbonyls in aerosol samples (i.e., total suspended particles) collected in Sapporo, northern Japan during spring and summer were determined to better understand the photochemical aging of organic aerosols during long-range transport from East Asia and Siberia. Their molecular distributions were characterized by the predominance of oxalic acid (C2) followed by malonic (C3) or occasionally succinic (C4) acids. Concentrations of total diacids ranged from 106-787 ng m-3 with ketoacids (13-81 ng m-3) and dicarbonyls (2.6-28 ng m-3) being less abundant. Water-soluble organic carbon (WSOC) comprised 23-69% of aerosol organic carbon (OC). OC to elemental carbon (EC) ratios were high (3.6-19, mean: 8.7). The ratios of C3/C4 and WSOC/OC did not show significant diurnal changes, suggesting that the Sapporo aerosols were not seriously affected by local photochemical processes and instead they were already aged. δ13C values of the dominant diacids (C2 - C4) ranged from -14.0 to -25.3‰. Largest δ13C values (-14.0 to -22.4‰, mean: -18.8‰) were obtained for C2, whereas smallest values (-25.1 to -31.4‰, mean: -28.1‰) were for azelaic acid (C9). In general, δ13C values of C2 - C4 diacids became less negative with aerosol aging (i.e., WSOC/OC), presumably due to isotopic fractionation during photochemical degradation of diacids. By comparing the δ13C values of diacids in the Sapporo aerosols with different air mass source regions, we suggest that although initial δ13C values of diacids depend on their precursor sources, the enrichment in 13C can be ascribed to aerosol photochemical aging.

  10. Structures of CoII and ZnII complexes of the proton-transfer compound derived from pyrazine-2,3-dicarboxylic acid and piperazine.

    PubMed

    Ghadermazi, Mohammad; Gharamaleki, Jafar Attar; Olmstead, Marilyn M; Almasi, Mehdi

    2015-07-01

    The reaction of the proton-transfer compound piperazine-1,4-diium pyrazine-2,3-dicarboxylate 4.5-hydrate, C4H12N2(2+)·C6H2N2O4(2-)·4.5H2O or (pipzH2)(pyzdc)·4.5H2O (pyzdcH2 is pyrazine-2,3-dicarboxylic acid and pipz is piperazine), (I), with Zn(NO3)2·6H2O and CoCl2·6H2O results in the formation of bis(piperazine-1,4-diium) bis(μ-pyrazine-2,3-dicarboxylato)-κ(3)N(1),O(2):O(3);κ(3)O(3):N(1),O(2)-bis[aqua(pyrazine-2,3-dicarboxylato-κ(2)N(1),O(2))zinc(II)] decahydrate, (C4H12N2)2[Zn2(C6H2N2O4)4(H2O)2]·10H2O or (pipzH2)2[Zn(pyzdc)2(H2O)]2·10H2O, (II), and catena-poly[piperazine-1,4-diium [cobalt(II)-bis(μ-pyrazine-2,3-dicarboxylato)-κ(3)N(1),O(2):O(3);κ(3)O(3):N(1),O(2)] hexahydrate], {(C4H12N2)[Co(C6H2N2O4)2]·6H2O}n or {(pipzH2)[Co(pyzdc)2]·6H2O}n, (III), respectively. In (I), pyzdcH2 is doubly deprotonated on reaction with piperazine as a base. Compound (II) crystallizes as a dimer, whereas compound (III) exists as a one-dimensional coordination polymer. In (II), two pyzdc(2-) groups chelate to each of the two Zn(II) atoms through a ring N atom and an O atom of the 2-carboxylate group. In one ligand, the adjacent 3-carboxylate group bridges to a neighbouring metal atom. A water molecule ligates in the sixth coordination site. The structure of (II) can be described as a commensurate superlattice due to an ordering in the hydrogen-bonded network. In (III), no water is coordinated to the metal atom and the coordination sphere is comprised of two N,O-chelates plus two bridging O atoms. A large number of hydrogen bonds are observed in all three compounds. These interactions, as well as π-π and C=O...π stacking interactions, play important structural roles. PMID:26146390

  11. Two new coordination polymers constructed by naphthalene-1,4-dicarboxylic acid and 2,4-diamino-6-methyl-triazine

    NASA Astrophysics Data System (ADS)

    Li, Yamin; Xiao, Changyu; Zhang, Xudong; Xu, Yanhui; Li, Junrui; Lun, Huijie; Chen, Qi

    2013-08-01

    Two new transition metal coordination complexes, {[MnO(nda)](H2dmt)(H2O)}n (1), [Ag5(nda)2.5(dmt)]n (2), (H2nda=naphthalene-1,4-dicarboxylic acid, dmt=2,4-diamine-6-methyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of H2nda and dmt with the homologous MnCl2·4H2O and AgNO3, respectively, and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis (TGA). The compound 1 exhibits a 3D network comprising 1D metal chain {MnO(CO2)2}n connected by the ligand nda2-, featuring a four-connected uninodal diamond -like topology. In compound 2, it is firstly observed that decanuclear silver units as secondary building units to construct 3D network by the ligands dmt and nda2-, with a rare 2-nodal (3,8)-connected tfz-d topology ({43}2{46.618.84}). The interactions within each Mn(II)-Mn(II) pair of compound 1 are antiferromagnetic (g=2.07, J=-1.42(1) cm-1, zj‧=-0.73(2) cm-1). In addition, compound 2 exhibits photoluminescent property at about 472 nm (λex=394 nm).

  12. The fate of P2Y-related orphan receptors: GPR80/99 and GPR91 are receptors of dicarboxylic acids.

    PubMed

    Gonzalez, Nathalie Suarez; Communi, Didier; Hannedouche, Sébastien; Boeynaems, Jean-Marie

    2004-12-01

    Several orphan G protein-coupled receptors are structurally close to the family of P2Y nucleotide receptors: GPR80/99 and GPR91 are close to P2Y(1/2/4/6/11) receptors, whereas GPR87, H963 and GPR34 are close to P2Y(12/13/14). Over the years, several laboratories have attempted without success to identify the ligands of those receptors. In early 2004, two papers have been published: One claiming that GPR80/99 is an AMP receptor, called P2Y(15), and the other one showing that GPR80/99 is a receptor for alpha-ketoglutarate, while GPR91 is a succinate receptor. The accompanying paper by Qi et al. entirely supports that GPR80/99 is an alpha-ketoglutarate receptor and not an AMP receptor. The closeness of dicarboxylic acid and P2Y nucleotide receptors might be linked to the negative charges of both types of ligands and the involvement of conserved Arg residues in their neutralization. PMID:18404396

  13. Cadmium and zinc chain and cluster-based layered coordination polymers prepared from flexible-arm aromatic ortho-dicarboxylic acids and 4-pyridylnicotinamide

    NASA Astrophysics Data System (ADS)

    Kraft, Peter E.; Uebler, Jacob W.; LaDuca, Robert L.

    2013-04-01

    Hydrothermal reaction of a d10-metal nitrate salt, a flexible-arm aromatic ortho-dicarboxylic acid, and 4-pyridylnicotinamide (4-pna) afforded four new crystalline coordination polymers, which were characterized by single-crystal X-ray diffraction. [Cd(Hhmph)(nic)(H2O)2]n (1, hmph = homophthalate, nic = nicotinate) is a 1-D coordination polymer chain compound whose nic ligands were generated in situ via 4-pna hydrolysis. Addition of base and a shorter reaction duration afforded [Cd(hmph)(4-pna)]n (2), which has dinuclear [Cd2(hmph)2] dimers linked into a 1-D ladder polymer via 4-pna ligands. A similar chain structure, albeit with a different hmph binding mode, is seen in [Zn(hmph)(4-pna)]n (3). {[Zn2(phda)2(4-pna)2(H2O)]ṡH2O}n (4, phda = 1,2-phenylenediacetate) has both anti-syn bridged [Zn2(OCO)2] ring dimers and [Zn2(OCO)4] paddlewheel dimers, linked into a layered coordination polymer by dipodal 4-pna ligands. Luminescent properties of these new materials are also presented.

  14. Cytotoxic Activity of Bioactive Compound 1, 2- Benzene Dicarboxylic Acid, Mono 2- Ethylhexyl Ester Extracted from a Marine Derived Streptomyces sp. VITSJK8

    PubMed Central

    Krishnan, Kannabiran; Mani, Abirami; Jasmine, Subashini

    2014-01-01

    Marine Streptomyces are prolific producers of majority of bioactive secondary metabolites which are used in pharmaceutical industry as effective drugs against life threatening diseases. The cytotoxic activity of the pure compound 1, 2- benzene dicarboxylic acid, mono 2- ethylhexyl ester (DMEHE) from marine derived actinomycete Streptomyces sp. VITSJK8 was investigated against mouse embryonic fibroblast (NIH 3T3) and human keratinocyte (HaCaT) normal cell lines, human hepatocellular liver carcinoma (HepG 2) and human breast adenocarcinoma (MCF-7) cell lines by using MTT assay. The compound DMEHE exhibited IC 50 values of 42, 100, 250 and 500 µg/ ml against HepG2, MCF-7, HaCaT and NIH 3T3 cell lines, respectively. The effect of DMEHE on the growth of cancer cell lines was expressed as the % of viability. Cell viability was recorded as 67.7%, 78.14%, 82.23% and 96. 11% in HepG2, MCF-7, HaCaT and NIH 3T3 cells, respectively. The results of the study conclude that the bioactive compound isolated from the potential isolate Streptomyces sp. VITSJK8 exhibited cytotoxic activity against HepG2 and MCF- 7 cancer cell lines and low toxicity against normal HaCaT and NIH 3T3 cell lines. PMID:25635251

  15. Plasma dynamics in double-pulse LIBS on dicarboxylic acids using combined 532 nm Nd:YAG and carbon dioxide laser pulses.

    PubMed

    Brown, Staci R; Akpovo, Charlemagne A; Martinez, Jorge; Johnson, Lewis

    2014-01-01

    Laser-induced breakdown spectroscopy (LIBS) was used as a method to monitor the evolution of C, hydrogen-α, carbon-carbon, and carbon-nitrogen spectral emissions from atmospheric recombination in a specific set of organic materials. Ablated samples were composed of a series of linear chain dicarboxylic acids with two to seven C atoms. Accumulated pulses of a focused neodymium-doped yttrium aluminum garnet (Nd:YAG) Q-switched laser beam operated at 532 nm generate a plasma in air at the sample surface. In this work, a dual-pulse LIBS technique was used to improve signal strength by enhancing the nanosecond LIBS plasma with CO2 transverse-excited breakdown in atmosphere laser pulses with an operating wavelength of 10.6 μm. Through a time-resolved analysis, we demonstrate the correlation between the signal strength of selected emissions and the number of C atoms in the linear chain. We also illustrate the effects that these constraints, along with the presence of a chiral C in the chain, have on the peak intensities of the individual lines with respect to each other by comparing the increase or nonexistence of certain spectral lines as we increase the number of C atoms in the linear chain.

  16. Origin of C2-C5 dicarboxylic acids in the European atmosphere inferred from year-round aerosol study conducted at a west-east transect

    NASA Astrophysics Data System (ADS)

    Legrand, M.; Preunkert, S.; Oliveira, T.; Pio, C. A.; Hammer, S.; GelencséR, A.; Kasper-Giebl, A.; Laj, P.

    2007-12-01

    An atmospheric study of C2-C5 dicarboxylic acids was conducted over two years at seven sites located from the Azores to eastern continental European sites. The lowest concentrations of total C2-C5 diacids are observed at the Azores (Portugal) and at 4360 m elevation in the Alps (˜50 ng m-3), and the highest (400 ng m-3) are observed at the rural K-puszta site (Hungary). Quasi-absent at surface sites, the seasonal cycle of total diacids is characterized by a pronounced summer maximum at elevated sites, the highest summer level (510 ng m-3) being observed at the forested mountain site of Schauinsland (Germany). Whatever site and season, oxalic acid is always the most abundant diacid with a relative abundance higher than 60%. The climatology of C2-C5 diacids in Europe is discussed versus environmental conditions at sites (marine/continental, rural/forested, boundary layer/free troposphere, and winter/summer). Observations are used to discuss the possible sources of C2-C5 diacids, with special emphasis on their primary versus secondary and natural versus anthropogenic origin. At surface sites in winter, fast secondary productions in wood burning plumes in addition to secondary production from volatile organic carbon (VOC) species emitted by vehicles seem to be important contributors. In summer the impact of anthropogenic sources is weakened and biogenic emissions from vegetation (unsaturated fatty acids, isoprene, oxygenated VOCs, and eventually monoterpenes) likely represent major precursors of diacids. At the Azores, diacids are not only related to long-range transport from continents but also to marine biogenic emissions from phytoplankton, particularly in summer.

  17. Comparison of dicarboxylic acids and related compounds in aerosol samples collected in Xi'an, China during haze and clean periods

    NASA Astrophysics Data System (ADS)

    Cheng, Chunlei; Wang, Gehui; Zhou, Bianhong; Meng, Jingjing; Li, Jianjun; Cao, Junji; Xiao, Shun

    2013-12-01

    PM10 aerosols from Xi'an, a mega city of China in winter and summer, 2009 were measured for secondary organic aerosols (SOA) (i.e., dicarboxylic acids (DCA), keto-carboxylic acids, and α-dicarbonyls), water-soluble organic (WSOC) and inorganic carbon (WSIC), elemental carbon (EC) and organic carbon (OC). Molecular compositions of SOA on haze and clean days in both seasons were compared to investigate their sources and formation mechanisms. DCA in the samples were 1843 ± 810 ng m-3 in winter and 1259 ± 781 ng m-3 in summer, respectively, which is similar and even higher than those measured in 2003. Oxalic acid (C2, 1162 ± 570 ng m-3 in winter and 1907 ± 707 ng m-3 in summer) is the predominant species of DCA, followed by t-phthalic (tPh) in winter and phthalic (Ph) in summer. Such a molecular composition is different from those in other Asian cities where succinic acid (C4) or malonic acid (C3) is the second highest species, which is mostly due to significant emissions from household combustion of coal and open burning of waste material in Xi'an. Mass ratios of C2/diacids, diacids/WSOC, WSOC/OC and individual diacid-C/WSOC are higher on the haze days than on the clean days in both seasons, suggesting an enhanced SOA production under the haze condition. We also found that the haze samples are acidic while the clean samples are almost neutral. Such a difference in particle acidity is consistent with the enhanced SOA production, because acid-catalysis is an important aqueous-phase formation pathway of SOA. Gly/mGly mass ratio showed higher values on haze days than on clean day in both seasons. We comprehensively investigated the ratio in literature and found a consistent pattern. Based on our observation results and those documented data we proposed for the first time that concentration ratio of Gly/mGly can be taken as an indicator of aerosol ageing.

  18. Dicarboxylic acid anhydride condensation with compounds containing active methylene groups. 4: Some 4-nitrophthalic anhydride condensation reactions

    NASA Technical Reports Server (NTRS)

    Oskaja, V.; Rotberg, J.

    1985-01-01

    By 4-nitrophthalic anhydride condensation with acetoacetate in acetic anhydride and triethylamine solution with subsequent breakdown of the intermediate condensation product, 5-nitroindanedione-1,3 was obtained. A 4-nitrophthalic anhydride with acetic anhydride, according to reaction conditions, may yield two products: in the presence of potassium acetate and at high temperatures 4-(or 5-)-nitro-2-acetylbenzoic acid is formed: in the presence of triethylamine and at room temperature 5-( or 6-)-nitrophthalic acetic acid is isolated. A 4-nitrophthalic anhydride and malonic acid in pyridine solution according to temperature yield either 5-( or 6-)-nitrophthalic acetic acid or 4-(or 5-)-nitro-2-acetylbenzoic acid.

  19. Novel heteroleptic lanthanide organic frameworks containing pyridine-2,5-dicarboxylic acid and in situ generated piperazine-2,5-dicarboxylic acid from piperazine: Hydrothermal synthesis and luminescent properties

    NASA Astrophysics Data System (ADS)

    Ay, Burak; Yildiz, Emel; Kani, İbrahim

    2016-01-01

    Two novel 3D lanthanide metal-organic frameworks [Ln(pydc)(pip)1/2(H2O] (Ln=Ce (1) and Pr (2), H2pydc=2,5-pyridinedicarboxylic acid, H2pip=2,5-piperazinedicarboxylic acid have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffractions (PXRD), and single-crystal X-ray diffractions. Field emission scanning electron microscopy (FESEM) was used for morphological analysis. Complexes are isostructural and feature interesting 3D frameworks. Both compounds crystallize in the monoclinic system, space group P21/c. Structural analyses of 1 and 2 show that Ln3+ ions connect with each other through H2pydc and H2pip. To the best of our knowledge, they are the first heteroleptic lanthanide polymers obtained through in situ 2,5-piperazinedicarboxylic acid syntheses. Moreover, thermal and luminescent properties of the compounds have been investigated.

  20. Vanadium(IV/V) speciation of pyridine-2,6-dicarboxylic acid and 4-hydroxy-pyridine-2,6-dicarboxylic acid complexes: potentiometry, EPR spectroscopy and comparison across oxidation states.

    PubMed

    Jakusch, Tamás; Jin, Wenzheng; Yang, Luqin; Kiss, Tamás; Crans, Debbie C

    2003-05-01

    Evaluation of stability of vanadium(IV) and (V) complexes under similar conditions is critical for the interpretation and assessment of bioactivity of various vanadium species. Detailed understanding of the chemical properties of these complexes is necessary to explain differences observed their activity in biological systems. These studies are carried out to link the chemistry of both vanadium(IV) and (V) complexes of two ligands, 2,6-pyridinedicarboxylic acid (dipicolinic acid, H(2)dipic) and 4-hydroxy-2,6-pyridinedicarboxylic acid (H(2)dipic-OH). Solution speciation of the two 2,6-pyridinedicarboxylic acids with vanadium(IV) and vanadium(V) ions was determined by pH-potentiometry at I=0.2 M (KCl) ionic strength and at T=298 K. The stability and the metal affinities of the ligands were compared. Vanadium(V) complexes were found to form only tridentate coordinated 1:1 complexes, while vanadium(IV) formed complexes with both 1:1 and 1:2 stoichiometries. The formation constant reflects hindered coordination of a second ligand molecule, presumably because of the relatively small size of the metal ion. The most probable binding mode of the complexes was further explored using ambient and low temperature EPR spectroscopy for vanadium(IV) and 51V NMR spectroscopy for vanadium(V) systems. Upon complex formation the pyridinol-OH in position 4 deprotonates with pK approximately 3.7-4.1, which is approximately 6 orders of magnitude lower than that of the free ligand. The deprotonation enhances the ligand metal ion affinity compared to the parent ligand dipicolinic acid. In the light of the speciation and stability data of the metal complexes, the efficiency of the two ligands in transporting the metal ion in the two different oxidation states are assessed and discussed.

  1. A base-mediated self-propagative Lossen rearrangement of hydroxamic acids for the efficient and facile synthesis of aromatic and aliphatic primary amines.

    PubMed

    Ohtsuka, Naoya; Okuno, Moriaki; Hoshino, Yujiro; Honda, Kiyoshi

    2016-10-14

    A variety of aromatic and aliphatic hydroxamic acids were converted to the corresponding primary amines via base-mediated rearrangement. This rearrangement could proceed with less than 1 equiv. of K2CO3 in polar solvents under thermal conditions with no external reagents. This rearrangement has several features including no external activating agents needed for promoting the rearrangement, less than one equivalent of a base is sufficient for the reaction, and a clean reaction in which only carbon dioxide is produced as a by-product. A self-propagating mechanism via an isocyanate intermediate is proposed and elementary reaction steps, namely, chain propagation reactions are supported by experiments. PMID:27605448

  2. Directing Group in Decarboxylative Cross-Coupling: Copper-Catalyzed Site-Selective C-N Bond Formation from Nonactivated Aliphatic Carboxylic Acids.

    PubMed

    Liu, Zhao-Jing; Lu, Xi; Wang, Guan; Li, Lei; Jiang, Wei-Tao; Wang, Yu-Dong; Xiao, Bin; Fu, Yao

    2016-08-01

    Copper-catalyzed directed decarboxylative amination of nonactivated aliphatic carboxylic acids is described. This intramolecular C-N bond formation reaction provides efficient access to the synthesis of pyrrolidine and piperidine derivatives as well as the modification of complex natural products. Moreover, this reaction presents excellent site-selectivity in the C-N bond formation step through the use of directing group. Our work can be considered as a big step toward controllable radical decarboxylative carbon-heteroatom cross-coupling. PMID:27439145

  3. A base-mediated self-propagative Lossen rearrangement of hydroxamic acids for the efficient and facile synthesis of aromatic and aliphatic primary amines.

    PubMed

    Ohtsuka, Naoya; Okuno, Moriaki; Hoshino, Yujiro; Honda, Kiyoshi

    2016-10-14

    A variety of aromatic and aliphatic hydroxamic acids were converted to the corresponding primary amines via base-mediated rearrangement. This rearrangement could proceed with less than 1 equiv. of K2CO3 in polar solvents under thermal conditions with no external reagents. This rearrangement has several features including no external activating agents needed for promoting the rearrangement, less than one equivalent of a base is sufficient for the reaction, and a clean reaction in which only carbon dioxide is produced as a by-product. A self-propagating mechanism via an isocyanate intermediate is proposed and elementary reaction steps, namely, chain propagation reactions are supported by experiments.

  4. Hydrolytic synthesis of novel lanthanide(III) complexes with pyridine-2,6-dicarboxylic acid: Characterization of the structure and the physical properties

    NASA Astrophysics Data System (ADS)

    Hojnik, Nuša; Kristl, Matjaž; Golobič, Amalija; Jagličić, Zvonko; Drofenik, Miha

    2015-01-01

    The coordination compounds of pyridine-2,6-dicarboxylic acid and two lanthanide(III) ions, Ho3+ and Dy3+, were hydrolytically synthesized in aqueous solutions at a slightly basic pH, and then characterized by thermogravimetric analysis, IR spectroscopy, magnetic measurements as well as X-ray powder and single-crystal diffraction analysis. The elemental analyses were performed to check the purity of the compounds. The formula for these compounds is identified as Na3[Ln(Pydc)3]ṡ14H2O (Ln = Ho, 1; Ln = Dy, 2) in agreement with the X-ray structural analysis and all the other experimental data. The absence of the 1709 cm-1 band corresponding to ν(C dbnd O) in the IR spectra of the compounds evidences the deprotonating of the carboxyl group. The very strong inductive effect of the metal ion that is readily coordinated by the carboxylate group of the zwitterionic ligand is responsible for the formation of the product. The single-crystal X-ray structural analysis revealed that compounds 1 and 2 are isostructural. Their structure can be described as interchanging layers of complex anions [Ln(Pydc)3]3 (Ln = Ho and Dy for 1 and 2, respectively) and layers of hydrated sodium cations. In complex anions the holmium and dysprosium atoms are coordinated by three crystallographically independent pyridinedicarboxylate ligands in tridentate-chelate mode, via one O atom of both carboxylate groups and the ring N atom. The coordination number is nine and the coordination polyhedron is a tricapped trigonal prism with O atoms at the corners.

  5. Peptidyl prolyl isomerase Pin1-inhibitory activity of D-glutamic and D-aspartic acid derivatives bearing a cyclic aliphatic amine moiety.

    PubMed

    Nakagawa, Hidehiko; Seike, Suguru; Sugimoto, Masatoshi; Ieda, Naoya; Kawaguchi, Mitsuyasu; Suzuki, Takayoshi; Miyata, Naoki

    2015-12-01

    Pin1 is a peptidyl prolyl isomerase that specifically catalyzes cis-trans isomerization of phosphorylated Thr/Ser-Pro peptide bonds in substrate proteins and peptides. Pin1 is involved in many important cellular processes, including cancer progression, so it is a potential target of cancer therapy. We designed and synthesized a novel series of Pin1 inhibitors based on a glutamic acid or aspartic acid scaffold bearing an aromatic moiety to provide a hydrophobic surface and a cyclic aliphatic amine moiety with affinity for the proline-binding site of Pin1. Glutamic acid derivatives bearing cycloalkylamino and phenylthiazole groups showed potent Pin1-inhibitory activity comparable with that of known inhibitor VER-1. The results indicate that steric interaction of the cyclic alkyl amine moiety with binding site residues plays a key role in enhancing Pin1-inhibitory activity.

  6. Simultaneous ion-exclusion chromatography and cation-exchange chromatography of anions and cations in environmental water samples on a weakly acidic cation-exchange resin by elution with pyridine-2,6-dicarboxylic acid.

    PubMed

    Ding, M Y; Tanaka, K; Hu, W; Hasebe, K; Haddad, P R

    2001-05-01

    A non-suppressed conductivity detection ion chromatographic method using a weakly acidic cation-exchange column (Tosoh TSKgel OApak-A) was developed for the simultaneous separation and determination of common inorganic anions (Cl-, NO3- and SO4(2-)) and cations (Na+, NH4+, K+, Mg2+ and Ca2+). A satisfactory separation of these anions and cations on the weakly acidic cation-exchange column was achieved in 25 min by elution with a mixture of 1.6 mmol L-1 pyridine-2,6-dicarboxylic acid and 8.0 mmol L-1 18-crown-6 at flow rate of 1.0 mL min-1. On this weakly acidic cation-exchange resin, anions were retained by an ion-exclusion mechanism and cations by a cation-exchange mechanism. The linear range of the peak area calibration curves for all analytes were up to two orders of magnitude. The detection limits calculated at S/N = 3 ranged from 0.25 to 1.9 mumol L-1 for anions and cations. The ion-exclusion chromatography-cation-exchange chromatography method developed in this work was successfully applied to the simultaneous determination of major inorganic anions and cations in rainwater, tap water and snow water samples.

  7. Use of a polystyrene-divinylbenzene-based weakly acidic cation-exchange resin column and propionic acid as an eluent in ion-exclusion/adsorption chromatography of aliphatic carboxylic acids and ethanol in food samples.

    PubMed

    Mori, Masanobu; Hironaga, Takahiro; Kajiwara, Hiroe; Nakatani, Nobutake; Kozaki, Daisuke; Itabashi, Hideyuki; Tanaka, Kazuhiko

    2011-01-01

    We developed an ion-exclusion/adsorption chromatography (IEAC) method employing a polystyrene-divinylbenzene-based weakly acidic cation-exchange resin (PS-WCX) column with propionic acid as the eluent for the simultaneous determination of multivalent aliphatic carboxylic acids and ethanol in food samples. The PS-WCX column well resolved mono-, di-, and trivalent carboxylic acids in the acidic eluent. Propionic acid as the eluent gave a higher signal-to-noise ratio, and enabled sensitive conductimetric detection of analyte acids. We found the optimal separation condition to be the combination of a PS-WCX column and 20-mM propionic acid. Practical applicability of the developed method was confirmed by using a short precolumn with a strongly acidic cation-exchange resin in the H(+)-form connected before the separation column; this was to remove cations from food samples by converting them to hydrogen ions. Consequently, common carboxylic acids and ethanol in beer, wine, and soy sauce were successfully separated by the developed method.

  8. Synthesis and Preclinical Evaluation of Radioiodinated Hypericin Dicarboxylic Acid as a Necrosis Avid Agent in Rat Models of Induced Hepatic, Muscular, and Myocardial Necroses.

    PubMed

    Li, Jindian; Zhang, Jian; Yang, Shengwei; Jiang, Cuihua; Zhang, DongJian; Jin, Qiaomei; Wang, Qin; Wang, Cong; Ni, Yicheng; Yin, Zhiqi; Song, Shaoli

    2016-01-01

    Myocardial infarction (MI) leads to substantial morbidity and mortality around the world. Accurate assessment of myocardial viability is essential to assist therapies and improve patient outcomes. (131)I-hypericin dicarboxylic acid ((131)I-HDA) was synthesized and evaluated as a potential diagnostic agent for earlier assessment of myocardium viability compared to its preceding counterpart (131)I-hypericin ((131)I-Hyp) with strong hydrophobic property, long plasma half-life, and high uptake in mononuclear phagocyte system (MPS). Herein, HDA was synthesized and characterized, and self-aggregation constant Kα was analyzed by spectrophotometry. Plasma half-life was determined in healthy rats by γ-counting. (131)I-HDA and (131)I-Hyp were prepared with iodogen as oxidant. In vitro necrosis avidity of (131)I-HDA and (131)I-Hyp was evaluated in necrotic cells induced by hyperthermia. Biodistribution was determined in rat models of induced necrosis using γ-counting, autoradiography, and histopathology. Earlier imaging of necrotic myocardium to assess myocardial viability was performed in rat models of reperfused myocardium infarction using single photon emission computed tomography/computed tomography (SPECT/CT). As a result, the self-aggregation constant Kα of HDA was lower than that of Hyp (105602 vs 194644, p < 0.01). (131)I-HDA displayed a shorter blood half-life compared with (131)I-Hyp (9.21 vs 31.20 h, p < 0.01). The necrotic-viable ratio in cells was higher with (131)I-HDA relative to that with (131)I-Hyp (5.48 vs 4.63, p < 0.05). (131)I-HDA showed a higher necrotic-viable myocardium ratio (7.32 vs 3.20, p < 0.01), necrotic myocardium-blood ratio (3.34 vs 1.74, p < 0.05), and necrotic myocardium-lung ratio (3.09 vs 0.61, p < 0.01) compared with (131)I-Hyp. (131)I-HDA achieved imaging of necrotic myocardium at 6 h postinjection (p.i.) with SPECT/CT, earlier than what (131)I-Hyp did. Therefore, (131)I-HDA may serve as a promising necrosis-avid diagnostic agent for

  9. Structures and standard molar enthalpies of formation of a series of Ln(III)–Cu(II) heteronuclear compounds with pyrazine-2,3-dicarboxylic acid

    SciTech Connect

    Yang, Qi; Xie, Gang; Wei, Qing; Chen, Sanping Gao, Shengli

    2014-07-01

    Fifteen lanthanide–copper heteronuclear compounds, formulated as [CuLn{sub 2}(pzdc){sub 4}(H{sub 2}O){sub 6}]·xH{sub 2}O (1–6(x=2), 8(x=3), 9–10(x=4)); [CuLn{sub 2}(pzdc){sub 4}(H{sub 2}O){sub 4}]·xH{sub 2}O (7, 12–13, 15(x=4), 14(x=5), 11(x=8)) (Ln(III)=La(1); Ce(2); Pr(3); Nd(4); Sm(5); Eu(6); Gd(7); Tb(8); Dy(9); Ho(10); Er(11); Tm(12); Yb(13); Lu(14); Y(15); H{sub 2}pzdc (C{sub 6}H{sub 4}N{sub 2}O{sub 4})=pyrazine-2,3-dicarboxylic acid) have been hydrothermally synthesized. All compounds were characterized by element analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. X-ray diffraction analyses confirm that all compounds are isostructural and feature a 3D brick-like framework structure with (4.6{sup 2}){sub 2}(4{sup 2}.6{sup 2}.8{sup 2})(6{sup 3}){sup 2}(6{sup 5}.8){sub 2} topology. Using 1 mol cm{sup −3} HCl(aq) as calorimetric solvent, with an isoperibol solution–reaction calorimeter, the standard molar enthalpies of formation of all compounds were determined by a designed thermochemical cycle. In addition, solid state luminescence properties of compounds 5, 6, 8 and 9 were studied in the solid state. - Graphical abstract: According to Hess' rule, the standard molar enthalpies of formation of Ln–Cu heterometallic coordination compounds were determined by a designed thermochemical cycle. - Highlights: • Fifteen lanthanide–copper heteronuclear isostructural compounds. • Structurally characterization by IR, X-ray diffraction and thermal analysis. • The standard molar enthalpy of formation. • Isoperibol solution–reaction calorimetry.

  10. Two new coordination polymers constructed by naphthalene-1,4-dicarboxylic acid and 2,4-diamino-6-methyl-triazine

    SciTech Connect

    Li, Yamin; Xiao, Changyu; Zhang, Xudong; Xu, Yanhui; Li, Junrui; Lun, Huijie; Chen, Qi

    2013-08-15

    Two new transition metal coordination complexes, ([MnO(nda)](H{sub 2}dmt)(H{sub 2}O)){sub n} (1), [Ag{sub 5}(nda){sub 2.5}(dmt)]{sub n} (2), (H{sub 2}nda=naphthalene-1,4-dicarboxylic acid, dmt=2,4-diamine-6-methyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of H{sub 2}nda and dmt with the homologous MnCl{sub 2}·4H{sub 2}O and AgNO{sub 3}, respectively, and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis (TGA). The compound 1 exhibits a 3D network comprising 1D metal chain (MnO(CO{sub 2}){sub 2}){sub n} connected by the ligand nda{sup 2−}, featuring a four-connected uninodal diamond -like topology. In compound 2, it is firstly observed that decanuclear silver units as secondary building units to construct 3D network by the ligands dmt and nda{sup 2−}, with a rare 2-nodal (3,8)-connected tfz-d topology ((4{sup 3}){sub 2}(4{sup 6}.6{sup 18}.8{sup 4})). The interactions within each Mn(II)—Mn(II) pair of compound 1 are antiferromagnetic (g=2.07, J=−1.42(1) cm{sup −1}, zj′=−0.73(2) cm{sup −1}). In addition, compound 2 exhibits photoluminescent property at about 472 nm (λ{sub ex}=394 nm). - Graphical abstract: Two new transition metal coordination complexes 1–2 have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis thermogravimetric analysis (TGA). Highlights: • The compound 1 exhibits a 3D network with four-connected uninodal diamond-like topology. • The first 3D network of 2 with a rare tfz-d topology consists of decanuclear silver clusters as secondary building units. • The magnetic measurement indicates the compound 1 shows antiferromagnetic interactions. • The photoluminescent property of 2 has been measured.

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

    PubMed

    Gill, Iqbal; Patel, Ramesh

    2006-02-01

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

  12. The Flögel-three-component reaction with dicarboxylic acids - an approach to bis(β-alkoxy-β-ketoenamides) for the synthesis of complex pyridine and pyrimidine derivatives.

    PubMed

    Bera, Mrinal K; Domínguez, Moisés; Hommes, Paul; Reissig, Hans-Ulrich

    2014-01-01

    An extension of the substrate scope of the Flögel-three-component reaction of lithiated alkoxyallenes, nitriles and carboxylic acids is presented. The use of dicarboxylic acids allowed the preparation of symmetrical bis(β-ketoenamides) from simple starting materials in moderate yields. Cyclocondensations of these enamides to 4-hydroxypyridine derivatives or to functionalized pyrimidines efficiently provided symmetrically and unsymmetrically substituted fairly complex (hetero)aromatic compounds containing up to six conjugated aryl and hetaryl groups. In addition, subsequent functionalizations of the obtained heterocycles by palladium-catalyzed couplings or by oxidations are reported. We also describe the simple synthesis of a structurally interesting macrocyclic bispyrimidine derivative incorporating a 17-membered ring, whose configuration was elucidated by DFT calculations and by subsequent reactions. PMID:24605160

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

    PubMed

    Gill, Iqbal; Patel, Ramesh

    2006-02-01

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

  14. The Flögel-three-component reaction with dicarboxylic acids - an approach to bis(β-alkoxy-β-ketoenamides) for the synthesis of complex pyridine and pyrimidine derivatives.

    PubMed

    Bera, Mrinal K; Domínguez, Moisés; Hommes, Paul; Reissig, Hans-Ulrich

    2014-01-01

    An extension of the substrate scope of the Flögel-three-component reaction of lithiated alkoxyallenes, nitriles and carboxylic acids is presented. The use of dicarboxylic acids allowed the preparation of symmetrical bis(β-ketoenamides) from simple starting materials in moderate yields. Cyclocondensations of these enamides to 4-hydroxypyridine derivatives or to functionalized pyrimidines efficiently provided symmetrically and unsymmetrically substituted fairly complex (hetero)aromatic compounds containing up to six conjugated aryl and hetaryl groups. In addition, subsequent functionalizations of the obtained heterocycles by palladium-catalyzed couplings or by oxidations are reported. We also describe the simple synthesis of a structurally interesting macrocyclic bispyrimidine derivative incorporating a 17-membered ring, whose configuration was elucidated by DFT calculations and by subsequent reactions.

  15. The Flögel-three-component reaction with dicarboxylic acids – an approach to bis(β-alkoxy-β-ketoenamides) for the synthesis of complex pyridine and pyrimidine derivatives

    PubMed Central

    Bera, Mrinal K; Domínguez, Moisés; Hommes, Paul

    2014-01-01

    Summary An extension of the substrate scope of the Flögel-three-component reaction of lithiated alkoxyallenes, nitriles and carboxylic acids is presented. The use of dicarboxylic acids allowed the preparation of symmetrical bis(β-ketoenamides) from simple starting materials in moderate yields. Cyclocondensations of these enamides to 4-hydroxypyridine derivatives or to functionalized pyrimidines efficiently provided symmetrically and unsymmetrically substituted fairly complex (hetero)aromatic compounds containing up to six conjugated aryl and hetaryl groups. In addition, subsequent functionalizations of the obtained heterocycles by palladium-catalyzed couplings or by oxidations are reported. We also describe the simple synthesis of a structurally interesting macrocyclic bispyrimidine derivative incorporating a 17-membered ring, whose configuration was elucidated by DFT calculations and by subsequent reactions. PMID:24605160

  16. Influence of season and salinity on the exudation of aliphatic low molecular weight organic acids (ALMWOAs) by Phragmites australis and Halimione portulacoides roots

    NASA Astrophysics Data System (ADS)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2015-01-01

    Plant roots have the ability to produce and secrete substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere. This phenomenon occurs for several purposes, for instance, the detoxification of pollutants. Nevertheless, knowledge about the exudation of such substances from marsh plants roots is still scarce. This work aimed at studying: 1) the ability of marsh plants, freshly collected in estuarine marshes, to liberate ALMWOAs into the surrounding medium and 2) the influence of the physiological cycle of these plants on the exudation of those substances. In vitro experiments were carried out, in different seasons, with Phragmites australis and Halimione portulacoides (two marsh plants widely distributed in Europe). Root exudates were collected in freshwater to which plant specimens, in different physiological stages, were exposed. Both marsh plants were capable of liberating oxalic and citric acids into the surrounding medium. Formic acid was also released by P. australis roots and acetic acid by H. portulacoides. There was a seasonal effect on the liberation of ALMWOAs by both plant roots. Marked changes were registered in the nature and levels of the ALMWOAs liberated and such changes depended upon the season in which the specimens were collected. In growing season, a significantly higher liberation of oxalic and citric acids (and acetic acid but only in H. portulacoides case) was observed. For P. australis, formic acid was only found in the decaying stage (autumn and winter). The nature of the medium (in particular, salinity) was a feature conditioning the exudation of ALMWOAs. Both plants were shown to contribute for the presence of ALMWOAs in marsh rhizosediments (some ALMWOAs were found in pore waters extracted). The nature and extent of this contribution will be however dependent upon plants' physiological stage, in addition to plant species. Therefore, these features should be taken into consideration in the event of

  17. Synergistic effects in solvent-extraction systems based on alkylsalicylic acids. I. Extraction of trivalent rare-earth metals in the presence of aliphatic amides

    SciTech Connect

    Preston, J.S.; Preez, A.C. du

    1995-07-01

    Aliphatic carboxylic acid amides were found to cause synergistic shifts in the pH{sub 50} values for the extraction of the trivalent rare-earth metals from chloride media by solutions of alkylsalicylic acids in xylene. For the different types of amide examined, the synergistic shifts for the extraction of neodymium by 3,5-diisopropylsalicylic acid (DIPSA) generally decrease in the order: R.CO.NR{sub 2}` > R.CO.NHR` > R.CO.NH{sub 2}, where R and R` are alkyl groups. With the N,N-dialkyl amides (R.CO.NR{sub 2}`) and the N-alkyl amides (R.CO.NHR`), the extent of the synergistic effect decreases with increasing chain-branching in either of the alkyl groups R and R`. For additions to 0.25 M alkylsalicylic acid, the synergistic effect increases with concentrations of up to 0.1 M amide, and decreases with higher concentrations. The extent of the synergistic shift produced by a given amide, as well as the separation in pH{sub 50} values from lanthanum to lutetium, increases with increasing steric bulk of the alkylsalicylic acid used. The separations between adjacent lanthanides are too small to be of any practical interest, however. Measurement of the solubility of salicylic acids (HA) in xylene containing various amounts of N,N-dialkyl amide (L) indicate that essentially complete formation of the HA.L adduct takes place. Treatment of metal-distribution data by slope analysis, and measurement of the solubility of the neodymium-DIPSA complex in xylene in the presence of amide suggest that the mixed-ligand complex has the stoichiometry NdA{sub 3}L{sub 2}. 18 refs., 6 figs., 3 refs.

  18. Role of the reaction intermediates in determining PHIP (parahydrogen induced polarization) effect in the hydrogenation of acetylene dicarboxylic acid with the complex [Rh (dppb)]{sup +} (dppb: 1,4-bis(diphenylphosphino)butane)

    SciTech Connect

    Reineri, F.; Aime, S.; Gobetto, R.; Nervi, C.

    2014-03-07

    This study deals with the parahydrogenation of the symmetric substrate acetylene dicarboxylic acid catalyzed by a Rh(I) complex bearing the chelating diphosphine dppb (1,4-bis(diphenylphosphino)butane). The two magnetically equivalent protons of the product yield a hyperpolarized emission signal in the {sup 1}H-NMR spectrum. Their polarization intensity varies upon changing the reaction solvent from methanol to acetone. A detailed analysis of the hydrogenation pathway is carried out by means of density functional theory calculations to assess the structure of hydrogenation intermediates and their stability in the two solvents. The observed polarization effects have been accounted on the basis of the obtained structures. Insights into the lifetime of a short-lived reaction intermediate are also obtained.

  19. Analysis of aliphatic waxes associated with root periderm or exodermis from eleven plant species.

    PubMed

    Kosma, Dylan K; Rice, Adam; Pollard, Mike

    2015-09-01

    Aliphatic waxes can be found in association with suberized tissues, including roots. Non-polar lipids were isolated by rapid solvent extraction of mature regions of intact roots from eleven angiosperms, including both monocots and dicots. The majority of roots analyzed were taproots or tuberous taproots that had undergone secondary growth and thus were covered by a suberized periderm. The exceptions therein were maize (Zea mays L.) and rice (Oryza sativa L.), which present a suberized exodermis. The analysis herein focused on aliphatic waxes, with particular emphasis on alkyl hydroxycinnamates (AHCs). AHCs were widely distributed, absent from only one species, were found in both aerial and subterranean portions of tuberous taproots, and were associated with the fibrous roots of both maize and rice. Most species also contained monoacylglycerols, fatty alcohols and/or free fatty acids. Carrot (Daucus carrota L.) was the outlier, containing only free fatty acids, sterols, and polyacetylenes as identified components. Sterols were the only ubiquitous component across all roots analyzed. Monoacylglycerols of ω-hydroxy fatty acids were present in maize and rice root waxes. For species within the Brassiceae, wax compositions varied between subspecies or varieties and between aerial and subterranean portions of taproots. In addition, reduced forms of photo-oxidation products of ω-hydroxy oleate and its corresponding dicarboxylic acid (10,18-dihydroxy-octadec-8-enoate, 9,18-dihydroxy-octadec-10-enoate and 9-hydroxyoctadec-10-ene-1,18-dioate) were identified as naturally occurring suberin monomers in rutabaga (Brassica napus subsp. rapifera Metzg.) periderm tissues.

  20. Analysis of aliphatic waxes associated with root periderm or exodermis from eleven plant species.

    PubMed

    Kosma, Dylan K; Rice, Adam; Pollard, Mike

    2015-09-01

    Aliphatic waxes can be found in association with suberized tissues, including roots. Non-polar lipids were isolated by rapid solvent extraction of mature regions of intact roots from eleven angiosperms, including both monocots and dicots. The majority of roots analyzed were taproots or tuberous taproots that had undergone secondary growth and thus were covered by a suberized periderm. The exceptions therein were maize (Zea mays L.) and rice (Oryza sativa L.), which present a suberized exodermis. The analysis herein focused on aliphatic waxes, with particular emphasis on alkyl hydroxycinnamates (AHCs). AHCs were widely distributed, absent from only one species, were found in both aerial and subterranean portions of tuberous taproots, and were associated with the fibrous roots of both maize and rice. Most species also contained monoacylglycerols, fatty alcohols and/or free fatty acids. Carrot (Daucus carrota L.) was the outlier, containing only free fatty acids, sterols, and polyacetylenes as identified components. Sterols were the only ubiquitous component across all roots analyzed. Monoacylglycerols of ω-hydroxy fatty acids were present in maize and rice root waxes. For species within the Brassiceae, wax compositions varied between subspecies or varieties and between aerial and subterranean portions of taproots. In addition, reduced forms of photo-oxidation products of ω-hydroxy oleate and its corresponding dicarboxylic acid (10,18-dihydroxy-octadec-8-enoate, 9,18-dihydroxy-octadec-10-enoate and 9-hydroxyoctadec-10-ene-1,18-dioate) were identified as naturally occurring suberin monomers in rutabaga (Brassica napus subsp. rapifera Metzg.) periderm tissues. PMID:26143051

  1. Enrichment of aliphatic, alicyclic and aromatic acids by oil-degrading bacteria isolated from the rhizosphere of plants growing in oil-contaminated soil from Kazakhstan.

    PubMed

    Mikolasch, Annett; Omirbekova, Anel; Schumann, Peter; Reinhard, Anne; Sheikhany, Halah; Berzhanova, Ramza; Mukasheva, Togzhan; Schauer, Frieder

    2015-05-01

    Three microbial strains were isolated from the rhizosphere of alfalfa (Medicago sativa), grass mixture (Festuca rubra, 75 %; Lolium perenne, 20 %; Poa pratensis, 10 %), and rape (Brassica napus) on the basis of their high capacity to use crude oil as the sole carbon and energy source. These isolates used an unusually wide spectrum of hydrocarbons as substrates (more than 80), including n-alkanes with chain lengths ranging from C12 to C32, monomethyl- and monoethyl-substituted alkanes (C12-C23), n-alkylcyclo alkanes with alkyl chain lengths from 4 to 18 carbon atoms, as well as substituted monoaromatic and diaromatic hydrocarbons. These three strains were identified as Gordonia rubripertincta and Rhodococcus sp. SBUG 1968. During their transformation of this wide range of hydrocarbon substrates, a very large number of aliphatic, alicyclic, and aromatic acids was detected, 44 of them were identified by GC/MS analyses, and 4 of them are described as metabolites for the first time. Inoculation of plant seeds with these highly potent bacteria had a beneficial effect on shoot and root development of plants which were grown on oil-contaminated sand. PMID:25592733

  2. Enrichment of aliphatic, alicyclic and aromatic acids by oil-degrading bacteria isolated from the rhizosphere of plants growing in oil-contaminated soil from Kazakhstan.

    PubMed

    Mikolasch, Annett; Omirbekova, Anel; Schumann, Peter; Reinhard, Anne; Sheikhany, Halah; Berzhanova, Ramza; Mukasheva, Togzhan; Schauer, Frieder

    2015-05-01

    Three microbial strains were isolated from the rhizosphere of alfalfa (Medicago sativa), grass mixture (Festuca rubra, 75 %; Lolium perenne, 20 %; Poa pratensis, 10 %), and rape (Brassica napus) on the basis of their high capacity to use crude oil as the sole carbon and energy source. These isolates used an unusually wide spectrum of hydrocarbons as substrates (more than 80), including n-alkanes with chain lengths ranging from C12 to C32, monomethyl- and monoethyl-substituted alkanes (C12-C23), n-alkylcyclo alkanes with alkyl chain lengths from 4 to 18 carbon atoms, as well as substituted monoaromatic and diaromatic hydrocarbons. These three strains were identified as Gordonia rubripertincta and Rhodococcus sp. SBUG 1968. During their transformation of this wide range of hydrocarbon substrates, a very large number of aliphatic, alicyclic, and aromatic acids was detected, 44 of them were identified by GC/MS analyses, and 4 of them are described as metabolites for the first time. Inoculation of plant seeds with these highly potent bacteria had a beneficial effect on shoot and root development of plants which were grown on oil-contaminated sand.

  3. Synthesis of aliphatic esters of cinnamic acid as potential lipophilic antioxidants catalyzed by lipase B from Candida antarctica.

    PubMed

    Jakovetić, Sonja M; Jugović, Branimir Z; Gvozdenović, Milica M; Bezbradica, Dejan I; Antov, Mirjana G; Mijin, Dušan Z; Knežević-Jugović, Zorica D

    2013-08-01

    Immobilized lipase from Candida antarctica (Novozyme 435) was tested for the synthesis of various phenolic acid esters (ethyl and n-butyl cinnamate, ethyl p-coumarate and n-butyl p-methoxycinnamate). The second-order kinetic model was used to mathematically describe the reaction kinetics and to compare present processes quantitatively. It was found that the model agreed well with the experimental data. Further, the effect of alcohol type on the esterification of cinnamic acid was investigated. The immobilized lipase showed more ability to catalyze the synthesis of butyl cinnamate. Therefore, the process was optimized for the synthesis of butyl cinnamate as a function of solvent polarity (logP) and amount of biocatalyst. The highest ester yield of 60.7 % was obtained for the highest enzyme concentration tested (3 % w/w), but the productivity was for 34 % lower than the corresponding value obtained for the enzyme concentration of 1 % (w/w). The synthesized esters were purified, identified, and screened for antioxidant activities. Both DPPH assay and cyclic voltammetry measurement have shown that cinnamic acid esters have better antioxidant properties than cinnamic acid itself.

  4. Structural and spectroscopic properties of an aliphatic boronic acid studied by combination of experimental and theoretical methods

    NASA Astrophysics Data System (ADS)

    Cyrański, Michał K.; Jezierska, Aneta; Klimentowska, Paulina; Panek, Jarosław J.; Żukowska, GraŻyna Z.; Sporzyński, Andrzej

    2008-03-01

    Boronic acids have emerged as one of the most useful class of organoboron molecules, with application in synthesis, catalysis, analytical chemistry, supramolecular chemistry, biology, and medicine. In this study, the structural and spectroscopic properties of n-butylboronic acid were investigated using experimental and theoretical approaches. X-ray crystallography method provided structural information on the studied compound in the solid state. Infrared and Raman spectroscopy served as tools for the data collection on vibrational modes of the analyzed system. Car-Parrinello molecular dynamics simulations in solid state were carried out at 100 and 293K to investigate an environmental and temperature influence on molecular properties of the n-butylboronic acid. Analysis of interatomic distances of atoms involved in the intermolecular hydrogen bond was performed to study the proton motion in the crystal. Subsequently, Fourier transform of autocorrelation functions of atomic velocities and dipole moment was applied to study the vibrational properties of the compound. In addition, the inclusion of quantum nature of proton motion was performed for O-H stretching vibrational mode by application of the envelope method for intermolecular hydrogen-bonded system. The second part of the computational study consists of simulations performed in vacuo. Monomeric and dimeric forms of the n-butylboronic acid were investigated using density functional theory and Møller-Plesset second-order perturbation method. The basis set superposition error was estimated. Finally, atoms in molecules (AIM) theory was applied to study electron density topology and properties of the intermolecular hydrogen bond. Successful reproduction of the molecular properties of the n-butylboronic acid by computational methodologies, presented in the manuscript, indicates the way for future studies of large boron-containing organic systems of importance in biology or materials science.

  5. Structural and spectroscopic properties of an aliphatic boronic acid studied by combination of experimental and theoretical methods.

    PubMed

    Cyrański, Michał K; Jezierska, Aneta; Klimentowska, Paulina; Panek, Jarosław J; Zukowska, Grazyna Z; Sporzyński, Andrzej

    2008-03-28

    Boronic acids have emerged as one of the most useful class of organoboron molecules, with application in synthesis, catalysis, analytical chemistry, supramolecular chemistry, biology, and medicine. In this study, the structural and spectroscopic properties of n-butylboronic acid were investigated using experimental and theoretical approaches. X-ray crystallography method provided structural information on the studied compound in the solid state. Infrared and Raman spectroscopy served as tools for the data collection on vibrational modes of the analyzed system. Car-Parrinello molecular dynamics simulations in solid state were carried out at 100 and 293 K to investigate an environmental and temperature influence on molecular properties of the n-butylboronic acid. Analysis of interatomic distances of atoms involved in the intermolecular hydrogen bond was performed to study the proton motion in the crystal. Subsequently, Fourier transform of autocorrelation functions of atomic velocities and dipole moment was applied to study the vibrational properties of the compound. In addition, the inclusion of quantum nature of proton motion was performed for O-H stretching vibrational mode by application of the envelope method for intermolecular hydrogen-bonded system. The second part of the computational study consists of simulations performed in vacuo. Monomeric and dimeric forms of the n-butylboronic acid were investigated using density functional theory and Moller-Plesset second-order perturbation method. The basis set superposition error was estimated. Finally, atoms in molecules (AIM) theory was applied to study electron density topology and properties of the intermolecular hydrogen bond. Successful reproduction of the molecular properties of the n-butylboronic acid by computational methodologies, presented in the manuscript, indicates the way for future studies of large boron-containing organic systems of importance in biology or materials science. PMID:18376948

  6. Synthesis, crystal structure and properties of two 1D nano-chain coordination polymers constructed by lanthanide with pyridine-3,4-dicarboxylic acid and 1,10-phenanthroline

    SciTech Connect

    Song Huihua Li Yajuan; Song You; Han Zhangang; Yang Fang

    2008-05-15

    The hydrothermal reactions of LnCl{sub 3}.6H{sub 2}O (Ln=Eu, Tb), pyridine-3,4-dicarboxylic acid (3,4-pydaH{sub 2}), 1,10-phenthroline (phen) and NaOH in aqueous medium yield two metal-organic hybrid materials, [Eu{sub 2}(3,4-pyda){sub 3}(phen)(H{sub 2}O).H{sub 2}O]{sub n} (1) and [Tb{sub 2}(3,4-pyda){sub 3}(phen)(H{sub 2}O).H{sub 2}O]{sub n} (2), respectively. Both compounds have similar topology structure containing one-dimensional nano-chain, which is further assembled into a three-dimensional supramolecular network via {pi}-{pi} stacking interactions and hydrogen bonds. To the best of our knowledge, they represent the first example of nano-chain coordination polymers constructed by 3,4-pydaH{sub 2} and chelate heterocylic ligand. Interestingly, the 3,4-pyda anion exhibits three kinds of coordination modes in these complexes. The coordination modes of 3,4-pyda in complexes 1 and 2 have not been observed in other coordination polymers containing 3,4-pyda ligands. Compounds 1 and 2 exhibit strong fluorescent emission bands in the solid state at room temperature. Their magnetic analyses show that they exhibit different magnetic interactions. - Graphical abstract: Two novel lanthanide coordination polymers [M{sub 2}(pydc){sub 3}(phen)(H{sub 2}O).H{sub 2}O]{sub n} (M=Eu(1) and Tb(2), pydc=pyridine-3,4-dicarboxylate, phen=1,10-phenthroline) have been synthesized and characterized. Both compounds reveal a one-dimensional nano-chain, which is further assembled into a three-dimensional supramolecular network via {pi}-{pi} stacking interactions and hydrogen bonds. Their luminescent and magnetic properties have been investigated.

  7. Microbial degradation of aliphatic and aliphatic-aromatic co-polyesters.

    PubMed

    Shah, Aamer Ali; Kato, Satoshi; Shintani, Noboru; Kamini, Numbi Ramudu; Nakajima-Kambe, Toshiaki

    2014-04-01

    Biodegradable plastics (BPs) have attracted much attention since more than a decade because they can easily be degraded by microorganisms in the environment. The development of aliphatic-aromatic co-polyesters has combined excellent mechanical properties with biodegradability and an ideal replacement for the conventional nondegradable thermoplastics. The microorganisms degrading these polyesters are widely distributed in various environments. Although various aliphatic, aromatic, and aliphatic-aromatic co-polyester-degrading microorganisms and their enzymes have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. In this review, we have reported some new microorganisms and their enzymes which could degrade various aliphatic, aromatic, as well as aliphatic-aromatic co-polyesters like poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(ε-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(L-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), and poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL). The mechanism of degradation of aliphatic as well as aliphatic-aromatic co-polyesters has also been discussed. The degradation ability of microorganisms against various polyesters might be useful for the treatment and recycling of biodegradable wastes or bioremediation of the polyester-contaminated environments.

  8. Distribution and sources of aliphatic hydrocarbons and fatty acids in surface sediments of a tropical estuary south west coast of India (Cochin estuary).

    PubMed

    Gireeshkumar, T R; Deepulal, P M; Chandramohanakumar, N

    2015-03-01

    Surface sediments samples from the Cochin estuary were measured for elemental, stable isotopic and molecular biomarkers (aliphatic hydrocarbons and fatty acids) to study the sources and distribution of sedimentary organic matter. Concentrations of total organic carbon (TOC), total nitrogen (TN) and stable isotopic ratios of carbon (δ(13)C) ranged from 0.62 to 2.74 %, 0.09 to 0.25 % and -27.5 to 21.7 ‰, respectively. Sedimentary n-alkanes ranged from 6.03 to 43.23 μg g(-1) with an average of 16.79 μg g(-1), while total fatty acids varied from 22.55 to 440.69 μg g(-1). The TOC/TN ratios and δ(13)C suggest a mixture of marine- and terrestrial-derived organic matter in the surface sediments with increasing contributions from marine-derived organic matter towards the seaward side. Long-chain n-alkanes derived from higher plants predominated the inner part of the estuary, while short-chain n-alkanes derived from planktonic sources predominated the bar mouth region. The even carbon preference of the C12-C22 n-alkanes may refer to the direct biogenic contribution from bacteria, fungi and yeast species and to the potential direct petroleum inputs. The presence of odd mid-chain n-alkanes in the sediments indicates the organic matter inputs from submerged and floating macrophytes (water hyacinth). Various molecular indices such as carbon preference index, terrestrial to aquatic ratio, average chain length and the ratios of mid-chain n-alkanes support the aforementioned inferences. The high contribution of odd and branched chain fatty acids along with very low contribution of polyunsaturated fatty acids, suggest the effective utilisation of algae-derived organic matter by bacteria and the effective recycling of labile organic matter in whole settling and deposition processes. The distributional variability of n-alkanes and fatty acids reveals the preferential utilisation of marine-derived organic matter and the selective preservation of terrestrial

  9. The enzymatic activities of the Escherichia coli basic aliphatic amino acid decarboxylases exhibit a pH zone of inhibition.

    PubMed

    Kanjee, Usheer; Gutsche, Irina; Ramachandran, Shaliny; Houry, Walid A

    2011-11-01

    The stringent response regulator ppGpp has recently been shown by our group to inhibit the Escherichia coli inducible lysine decarboxylase, LdcI. As a follow-up to this observation, we examined the mechanisms that regulate the activities of the other four E. coli enzymes paralogous to LdcI: the constitutive lysine decarboxylase LdcC, the inducible arginine decarboxylase AdiA, the inducible ornithine decarboxylase SpeF, and the constitutive ornithine decarboxylase SpeC. LdcC and SpeC are involved in cellular polyamine biosynthesis, while LdcI, AdiA, and SpeF are involved in the acid stress response. Multiple mechanisms of regulation were found for these enzymes. In addition to LdcI, LdcC and SpeC were found to be inhibited by ppGpp; AdiA activity was found to be regulated by changes in oligomerization, while SpeF and SpeC activities were regulated by GTP. These findings indicate the presence of multiple mechanisms regulating the activity of this important family of decarboxylases. When the enzyme inhibition profiles are analyzed in parallel, a "zone of inhibition" between pH 6 and pH 8 is observed. Hence, the data suggest that E. coli utilizes multiple mechanisms to ensure that these decarboxylases remain inactive around neutral pH possibly to reduce the consumption of amino acids at this pH. PMID:21957966

  10. The enzymatic activities of the Escherichia coli basic aliphatic amino acid decarboxylases exhibit a pH zone of inhibition.

    PubMed

    Kanjee, Usheer; Gutsche, Irina; Ramachandran, Shaliny; Houry, Walid A

    2011-11-01

    The stringent response regulator ppGpp has recently been shown by our group to inhibit the Escherichia coli inducible lysine decarboxylase, LdcI. As a follow-up to this observation, we examined the mechanisms that regulate the activities of the other four E. coli enzymes paralogous to LdcI: the constitutive lysine decarboxylase LdcC, the inducible arginine decarboxylase AdiA, the inducible ornithine decarboxylase SpeF, and the constitutive ornithine decarboxylase SpeC. LdcC and SpeC are involved in cellular polyamine biosynthesis, while LdcI, AdiA, and SpeF are involved in the acid stress response. Multiple mechanisms of regulation were found for these enzymes. In addition to LdcI, LdcC and SpeC were found to be inhibited by ppGpp; AdiA activity was found to be regulated by changes in oligomerization, while SpeF and SpeC activities were regulated by GTP. These findings indicate the presence of multiple mechanisms regulating the activity of this important family of decarboxylases. When the enzyme inhibition profiles are analyzed in parallel, a "zone of inhibition" between pH 6 and pH 8 is observed. Hence, the data suggest that E. coli utilizes multiple mechanisms to ensure that these decarboxylases remain inactive around neutral pH possibly to reduce the consumption of amino acids at this pH.

  11. An enhanced procedure for measuring organic acids and methyl esters in PM2.5

    NASA Astrophysics Data System (ADS)

    Liu, F.; Duan, F.; He, K.; Ma, Y.; Rahn, K. A.; Zhang, Q.

    2015-03-01

    We have developed an enhanced analytical procedure to measure organic acids and methyl esters in fine aerosol with much greater specificity and sensitivity than previously available. This capability is important because of these species and their low concentrations, even in highly polluted atmospheres like Beijing, China. The procedure first separates the acids and esters from the other organic compounds with anion-exchange solid- phase extraction (SPE), then, quantifies them by gas chromatography coupled with mass spectrometry. This allows us to accurately quantify the C4-C11 dicarboxylic and the C8-C30 monocarboxylic acids. Then the acids are separated from the esters on an aminopropyl SPE cartridge, whose weak retention isolates and enriches the acids from esters prevents the fatty acids and dimethyl phthalate from being overestimated. The resulting correlations between the aliphatic acids and fatty acid methyl esters (FAMEs) suggest that FAMEs had sources similar to those of the carboxylic acids, or were formed by esterifying carboxylic acids, or that aliphatic acids were formed by hydrolyzing FAMEs. In all, 17 aromatic acids were identified and quantified using this procedure coupled with gas chromatography-tandem mass spectrometry, including the five polycyclic aromatic hydrocarbon (PAH) acids 2-naphthoic, biphenyl-4-carboxylic, 9-oxo-9H-fluorene-1-carboxylic, biphenyl-4,4´-dicarboxylic, and phenanthrene-1-carboxylic acid, plus 1,8-naphthalic anhydride. Correlations between the PAH-acids and the dicarboxylic and aromatic acids indicated that the first three acids and 1,8-naphthalic anhydride were mainly secondary, the last two mainly primary.

  12. Molecular complexes of alprazolam with carboxylic acids, boric acid, boronic acids, and phenols. Evaluation of supramolecular heterosynthons mediated by a triazole ring.

    PubMed

    Varughese, Sunil; Azim, Yasser; Desiraju, Gautam R

    2010-09-01

    A series of molecular complexes, both co-crystals and salts, of a triazole drug-alprazolam-with carboxylic acids, boric acid, boronic acids, and phenols have been analyzed with respect to heterosynthons present in the crystal structures. In all cases, the triazole ring behaves as an efficient hydrogen bond acceptor with the acidic coformers. The hydrogen bond patterns exhibited with aromatic carboxylic acids were found to depend on the nature and position of the substituents. Being a strong acid, 2,6-dihydroxybenzoic acid forms a salt with alprazolam. With aliphatic dicarboxylic acids alprazolam forms hydrates and the water molecules play a central role in synthon formation and crystal packing. The triazole ring makes two distinct heterosynthons in the molecular complex with boric acid. Boronic acids and phenols form consistent hydrogen bond patterns, and these are seemingly independent of the substitutional effects. Boronic acids form noncentrosymmetric cyclic synthons, while phenols form O--H...N hydrogen bonds with the triazole ring.

  13. Controlled-release fertilizer prepared using a biodegradable aliphatic copolyester of poly(butylene succinate) and dimerized fatty acid.

    PubMed

    Lubkowski, Krzysztof; Smorowska, Aleksandra; Grzmil, Barbara; Kozłowska, Agnieszka

    2015-03-18

    The preparation and characterization of a controlled-release multicomponent (NPK) fertilizer with the coating layer consisting of a biodegradable copolymer of poly(butylene succinate) and a butylene ester of dilinoleic acid (PBS/DLA) is reported. The morphology and structure of the resulting polymer-coated materials and the thickness of the covering layers were examined using X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis. The mechanical properties of these materials were determined with a strength-testing machine. Nutrient release was measured in water using spectrophotometry, potentiometry, and conductivity methods. The results of the nutrient release experiments from these polymer-coated materials were compared with the requirements for controlled-release fertilizers. A conceptual model is presented describing the mechanism of nutrient release from the materials prepared in this study. This model is based on the concentrations of mineral components inside the water-penetrated fertilizer granules, the diffusion properties of the nutrients in water, and a diffusion coefficient through the polymer layer. The experimental kinetic data on nutrient release were interpreted using the sigmoidal model equation developed in this study. PMID:25715823

  14. Controlled-release fertilizer prepared using a biodegradable aliphatic copolyester of poly(butylene succinate) and dimerized fatty acid.

    PubMed

    Lubkowski, Krzysztof; Smorowska, Aleksandra; Grzmil, Barbara; Kozłowska, Agnieszka

    2015-03-18

    The preparation and characterization of a controlled-release multicomponent (NPK) fertilizer with the coating layer consisting of a biodegradable copolymer of poly(butylene succinate) and a butylene ester of dilinoleic acid (PBS/DLA) is reported. The morphology and structure of the resulting polymer-coated materials and the thickness of the covering layers were examined using X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis. The mechanical properties of these materials were determined with a strength-testing machine. Nutrient release was measured in water using spectrophotometry, potentiometry, and conductivity methods. The results of the nutrient release experiments from these polymer-coated materials were compared with the requirements for controlled-release fertilizers. A conceptual model is presented describing the mechanism of nutrient release from the materials prepared in this study. This model is based on the concentrations of mineral components inside the water-penetrated fertilizer granules, the diffusion properties of the nutrients in water, and a diffusion coefficient through the polymer layer. The experimental kinetic data on nutrient release were interpreted using the sigmoidal model equation developed in this study.

  15. An enhanced procedure for measuring organic acids and methyl esters in PM2.5

    NASA Astrophysics Data System (ADS)

    Liu, F.; Duan, F. K.; He, K. B.; Ma, Y. L.; Rahn, K. A.; Zhang, Q.

    2015-11-01

    A solid-phase extraction (SPE) pretreatment procedure allowing organic acids to be separated from methyl esters in fine aerosol has been developed. The procedure first separates the organic acids from fatty acid methyl esters (FAMEs) and other nonacid organic compounds by aminopropyl-based SPE cartridge and then quantifies them by gas chromatography/mass spectrometry. The procedure prevents the fatty acids and dimethyl phthalate from being overestimated, and so allows us to accurately quantify the C4-C11 dicarboxylic acids (DCAs) and the C8-C30 monocarboxylic acids (MCAs). Results for the extraction of DCAs, MCAs, and AMAs in eluate and FAMEs in effluate by SAX and NH2 SPE cartridges exhibited that the NH2 SPE cartridge gave higher extraction efficiency than the SAX cartridge. The recoveries of analytes ranged from 67.5 to 111.3 %, and the RSD ranged from 0.7 to 10.9 %. The resulting correlations between the aliphatic acids and FAMEs suggest that the FAMEs had sources similar to those of the carboxylic acids, or were formed by esterifying carboxylic acids, or that aliphatic acids were formed by hydrolyzing FAMEs. Through extraction and cleanup using this procedure, 17 aromatic acids in eluate were identified and quantified by gas chromatography/tandem mass spectrometry, including five polycyclic aromatic hydrocarbon (PAH): acids 2-naphthoic, biphenyl-4-carboxylic, 9-oxo-9H-fluorene-1-carboxylic, biphenyl-4,4´-dicarboxylic, and phenanthrene-1-carboxylic acid, plus 1,8-naphthalic anhydride. Correlations between the PAH acids and the dicarboxylic and aromatic acids suggested that the first three acids and 1,8-naphthalic anhydride were secondary atmospheric photochemistry products and the last two mainly primary.

  16. Synthesis and Pharmacological Characterization of C4-(Thiotriazolyl)-substituted-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylates. Identification of (1R,2S,4R,5R,6R)-2-Amino-4-(1H-1,2,4-triazol-3-ylsulfanyl)bicyclo[3.1.0]hexane-2,6-dicarboxylic Acid (LY2812223), a Highly Potent, Functionally Selective mGlu2 Receptor Agonist.

    PubMed

    Monn, James A; Prieto, Lourdes; Taboada, Lorena; Hao, Junliang; Reinhard, Matthew R; Henry, Steven S; Beadle, Christopher D; Walton, Lesley; Man, Teresa; Rudyk, Helene; Clark, Barry; Tupper, David; Baker, S Richard; Lamas, Carlos; Montero, Carlos; Marcos, Alicia; Blanco, Jaime; Bures, Mark; Clawson, David K; Atwell, Shane; Lu, Frances; Wang, Jing; Russell, Marijane; Heinz, Beverly A; Wang, Xushan; Carter, Joan H; Getman, Brian G; Catlow, John T; Swanson, Steven; Johnson, Bryan G; Shaw, David B; McKinzie, David L

    2015-09-24

    Identification of orthosteric mGlu(2/3) receptor agonists capable of discriminating between individual mGlu2 and mGlu3 subtypes has been highly challenging owing to the glutamate-site sequence homology between these proteins. Herein we detail the preparation and characterization of a series of molecules related to (1S,2S,5R,6S)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylate 1 (LY354740) bearing C4-thiotriazole substituents. On the basis of second messenger responses in cells expressing other recombinant human mGlu2/3 subtypes, a number of high potency and efficacy mGlu2 receptor agonists exhibiting low potency mGlu3 partial agonist/antagonist activity were identified. From this, (1R,2S,4R,5R,6R)-2-amino-4-(1H-1,2,4-triazol-3-ylsulfanyl)bicyclo[3.1.0]hexane-2,6-dicarboxylic acid 14a (LY2812223) was further characterized. Cocrystallization of 14a with the amino terminal domains of hmGlu2 and hmGlu3 combined with site-directed mutation studies has clarified the underlying molecular basis of this unique pharmacology. Evaluation of 14a in a rat model responsive to mGlu2 receptor activation coupled with a measure of central drug disposition provides evidence that this molecule engages and activates central mGlu2 receptors in vivo. PMID:26313429

  17. Rapid radiosynthesis of [11C] and [14C]azelaic, suberic, and sebacic acids for in vivo mechanistic studies of systemic acquired resistance in plants

    SciTech Connect

    Best M.; Fowler J.; Best, M.; Gifford, A.N.; Kim, S.W.; Babst, B.; Piel, M.; Roesch, F.; Fowler, J.S.

    2011-11-25

    A recent report that the aliphatic dicarboxylic acid, azelaic acid (1,9-nonanedioic acid) but not related acids, suberic acid (1,8-octanedioic acid) or sebacic (1,10-decanedioic acid) acid induces systemic acquired resistance to invading pathogens in plants stimulated the development of a rapid method for labeling these dicarboxylic acids with {sup 11}C and {sup 14}C for in vivo mechanistic studies in whole plants. {sup 11}C-labeling was performed by reaction of ammonium [{sup 11}C]cyanide with the corresponding bromonitrile precursor followed by hydrolysis with aqueous sodium hydroxide solution. Total synthesis time was 60 min. Median decay-corrected radiochemical yield for [{sup 11}C]azelaic acid was 40% relative to trapped [{sup 11}C]cyanide, and specific activity was 15 GBq/{micro}mol. Yields for [{sup 11}C]suberic and sebacic acids were similar. The {sup 14}C-labeled version of azelaic acid was prepared from potassium [{sup 14}C]cyanide in 45% overall radiochemical yield. Radiolabeling procedures were verified using {sup 13}C-labeling coupled with {sup 13}C-NMR and liquid chromatography-mass spectrometry analysis. The {sup 11}C and {sup 14}C-labeled azelaic acid and related dicarboxylic acids are expected to be of value in understanding the mode-of-action, transport, and fate of this putative signaling molecule in plants.

  18. Trans-hemispheric contribution of C2-C10 α, ω-dicarboxylic acids, and related polar compounds to water-soluble organic carbon in the western Pacific aerosols in relation to photochemical oxidation reactions

    NASA Astrophysics Data System (ADS)

    SempéRé, Richard; Kawamura, Kimitaka

    2003-06-01

    Marine aerosol samples were collected during a western Pacific cruise covering the latitude range between 35°N and 40°S (140°E-180°E). They were analyzed for total carbon (TC), total nitrogen (TN), water-soluble organic carbon (WSOC) along with the molecular distributions of C2-C10 α, ω-dicarboxylic acids, and related polar compounds, mainly, ω-oxocarboxylic acids (C2-C9) and α-dicarbonyls (C2-C3). Oxalic acid (C2) was the most abundant followed by malonic (C3) and succinic (C4) acids. The total diacid concentration range was 7-605 ng m-3 (av. 85 ng m-3) and the diacid-carbon accounted for 2-15% (average 8%) of WSOC which comprised 29-55% (average 40%) of TC. Dry depositions of total diacids over the northern and southern Pacific Ocean were estimated to be 256-1907 μg m-2 yr-1 (average 735; n = 4) and 22-396 μg m-2 yr-1 (average 134; n = 14), respectively, whereas the air-to-sea flux of oxalic acid was 18-1351 μg m-2 yr-1 (average 466 μg m-2 yr-1) and 7.5-275 μg m-2 yr-1 (average 75 μg m-2 yr-1) in the Northern and Southern Hemispheres. We observed that the concentration ratios of diacid-C/WSOC, azelaic acid (C9)/ω-oxononanoic acid, maleic acid (iC4cis)/fumaric (iC4trans) acid and succinic acid (C4)/total diacids were correlated with air temperature. These findings showed that the intensity of photochemical oxidation reactions and thus the variation in sunlight intensity characterized here by air temperature, significantly control the molecular distribution of water-soluble organic compounds during the long-range transport of anthropogenic and/or biogenic higher molecular weight organic compounds.

  19. (2,2'-Bipyridine-4,4'-dicarb-oxy-lic acid-κN,N')chlorido(2,2':6',2''-terpyridyl-κN,N',N'')ruthenium(II) perchlorate ethanol monosolvate monohydrate.

    PubMed

    Nielsen, Anne; McKenzie, Christine J; Bond, Andrew D

    2012-01-01

    In the title compound, [RuCl(C(15)H(11)N(3))(C(12)H(8)N(2)O(4))]ClO(4)·C(2)H(5)OH·H(2)O, the geometry of the ClN(5) coordination set around the Ru(II) atom is close to octa-hedral, but distorted on account of the limited bite angles of the polypyridyl ligands. The complexes are linked by O-H⋯O hydrogen bonds between the carboxyl groups and the crystal lattice water mol-ecules into chains along [110]. Face-to-face stacking inter-actions are formed between terpyridine ligands, with inter-planar separations of 3.66 (1) and 3.42 (1) Å, and between bipyridine-4,4'-dicarb-oxy-lic acid ligands, with inter-planar separations of 3.65 (1) and 3.72 (1) Å. Three O atoms of the perchlorate ion are each disordered equally over two positions. The hy-droxy group of the ethanol mol-ecule is also disordered over two sites with refined occupancies of 0.794 (9) and 0.206 (9). PMID:22259372

  20. Isolation of phenazine 1,6-di-carboxylic acid from Pseudomonas aeruginosa strain HRW.1-S3 and its role in biofilm-mediated crude oil degradation and cytotoxicity against bacterial and cancer cells.

    PubMed

    Dasgupta, Debdeep; Kumar, Abhinash; Mukhopadhyay, Balaram; Sengupta, Tapas K

    2015-10-01

    Pseudomonas sp. has long been known for production of a wide range of secondary metabolites during late exponential and stationary phases of growth. Phenazine derivatives constitute a large group of secondary metabolites produced by microorganisms including Pseudomonas sp. Phenazine 1,6-di-carboxylic acid (PDC) is one of such metabolites and has been debated for its origin from Pseudomonas sp. The present study describes purification and characterization of PDC isolated from culture of a natural isolate of Pseudomonas sp. HRW.1-S3 while grown in presence of crude oil as sole carbon source. The isolated PDC was tested for its effect on biofilm formation by another environmental isolate of Pseudomonas sp. DSW.1-S4 which lacks the ability to produce any phenazine compound. PDC showed profound effect on both planktonic as well as biofilm mode of growth of DSW.1-S4 at concentrations between 5 and 20 μM. Interestingly, PDC showed substantial cytotoxicity against three cancer cell lines and against both Gram-positive and Gram-negative bacteria. Thus, the present study not only opens an avenue to understand interspecific cooperation between Pseudomonas species which may lead its applicability in bioremediation, but also it signifies the scope of future investigation on PDC for its therapeutic applications.

  1. Molecular structure, vibrational spectroscopic (FT-IR, FT-Raman), UV-vis spectra, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis, thermodynamic properties of benzophenone 2,4-dicarboxylic acid by ab initio HF and density functional method

    NASA Astrophysics Data System (ADS)

    Chaitanya, K.

    2012-02-01

    The FT-IR (4000-450 cm -1) and FT-Raman spectra (3500-100 cm -1) of benzophenone 2,4-dicarboxylic acid (2,4-BDA) have been recorded in the condensed state. Density functional theory calculation with B3LYP/6-31G(d,p) basis set have been used to determine ground state molecular geometries (bond lengths and bond angles), harmonic vibrational frequencies, infrared intensities, Raman activities and bonding features of the title compounds. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability ( β0) and related properties ( β, α0 and Δ α) of 2,4-BDA is calculated using HF/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO analysis. The calculated first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charges is also calculated. Because of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-vis spectra and electronic absorption properties were explained and illustrated from the frontier molecular orbitals.

  2. Rainwater monocarboxylic and dicarboxylic acid concentrations in southeastern North Carolina, USA, as a function of air-mass back-trajectory

    NASA Astrophysics Data System (ADS)

    Brooks Avery, G.; Kieber, Robert J.; Witt, Melanie; Willey, Joan D.

    Eight organic acids were measured in 111 rain events occurring between September 1996 and May 1998 in Wilmington, North Carolina. Formic and acetic acids were the most abundant comprising approximately 75% of the total molar quantity of organic acids. The annual volume-weighted concentrations of organic acids in order of decreasing abundance in rainwater was formic (9.9 μM), acetic (7.3 μM), oxalic (1.8 μM), lactic (1.3 μM), succinic (1.0 μM), malonic (0.7 μM), pyruvic (0.3 μM), and maleic (0.1 μM), with methanesulfonic and glyoxylic acids usually below their detection limit. Growing season back-trajectory data provided strong evidence that terrestrial organic acid sources dominated over marine sources. Air mass back-trajectory analysis indicated that during the growing season air mass origin had a consistent impact on concentrations of rainwater organic acids. Rain with continental back-trajectories coming from the west had the highest concentrations of organic acids while two predominately marine back-trajectories had the lowest concentrations. Concentrations of organic acids in non-growing season rain did not display a consistent pattern indicating variability in sources. Seasonality of individual organic acids for specific back-trajectories was most pronounced in terrestrial back-trajectories and least in the marine back-trajectories indicating that seasonality in rainwater organic acid concentrations is driven by variations in terrestrial sources. Formic to acetic acid ratios (F:A), previously an indicator of terrestrial versus marine sources of these organic acids, were similar for all back-trajectories reflecting anthropogenic impacts on F:A locally and regionally. The ratios of malonic to succinic acids (M:S), also an indicator of sources for these acids, indicated direct anthropogenic sources for terrestrial back-trajectories and secondary processes for marine back-trajectories.

  3. CCN activity of aliphatic amine secondary aerosol

    NASA Astrophysics Data System (ADS)

    Tang, X.; Price, D.; Praske, E.; Vu, D.; Purvis-Roberts, K.; Silva, P. J.; Cocker, D. R., III; Asa-Awuku, A.

    2014-01-01

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical). The particle composition can contain both secondary organic aerosol (SOA) and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N2O5 (source of nitrate radical, NO3), contains less volatile compounds than the primary aliphatic amine (BA) aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. Higher CCN activity (κ > 0.3) was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2), as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3). Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss) settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 < κ < 0.7. This work indicates that

  4. A 3D POM–MOF composite based on Ni(ΙΙ) ion and 2,2´-bipyridyl-3,3´-dicarboxylic acid: Crystal structure and proton conductivity

    SciTech Connect

    Wei, Meilin; Wang, Xiaoxiang; Sun, Jingjing; Duan, Xianying

    2013-06-01

    We have succeeded in constructing a 3D POM–MOF, (H[Ni(Hbpdc)(H₂O)₂]₂[PW₁₂O₄₀]·8H₂O)n (H₂bpdc=2,2´-bipyridyl-3,3´-dicarboxylic acid), by the controllable self-assembly of H₂bpdc, Keggin-anions and Ni²⁺ ions based on the electrostatic and coordination interactions. Interestingly, Hbpdc⁻ as polydentate organic ligands and Keggin-anion as polydentate inorganic ligands are covalently linked transition-metal nickel at the same time. The title complex represents a new example of introducing the metal N-heterocyclic multi-carboxylic acid frameworks into POMs chemistry. Based on Keggin-anions being immobilized as part of the metal N-heterocyclic multi-carboxylic acid framework, the title complex realizes four approaches in the 1D hydrophilic channel used to engender proton conductivity in MOFs. Its water adsorption isotherm at room temperature and pressure shows that the water content in it was 31 cm³ g⁻¹ at the maximum allowable humidity, corresponding to 3.7 water molecules per unit formula. It exhibits good proton conductivities (10⁻⁴–10⁻³ S cm⁻¹) at 100 °C in the relative humidity range 35–98%. The corresponding activation energy (E{sub a}) of conductivity was estimated to be 1.01 eV. - Graphical abstract: A POM–MOF composite constructed by Keggin-type polyanion, Ni²⁺ and H₂bpdc shows good proton conductivities of 10⁻⁴–10⁻³ S cm⁻¹ at 100 °C under 35–98% RH. - Highlights: • A POM–MOF was constructed by combining metal N-heterocyclic multi-carboxylic acid framework and Keggin anion. • It opens a pathway for design and synthesis of multifunctional hybrid materials based on two building units. • Three types of potential proton-carriers have been assembled in the 1D hydrophilic channels of the POM–MOF. • It achieved such proton conductivities as 10⁻⁴–10⁻³ S cm⁻¹ at 100 °C in the RH range 35–98%.

  5. A novel copper(II) complex constructed with mixed ligands of biphenyl-4,4'-dicarboxylic acid (H 2bpdc) and dipyrido[3,2-d:2',3'-f]quinoxaline (Dpq): Synthesis, structure, electrochemistry and electrocatalysis

    NASA Astrophysics Data System (ADS)

    Lin, HongYan; Wang, XiuLi; Hu, HaiLiang; Chen, BaoKuan; Liu, GuoCheng

    2009-03-01

    A novel metal-organic framework [Cu 2(bpdc) 2(Dpq) 2(H 2O)]·H 2O ( 1) has been obtained from hydrothermal reaction of copper chloride with the mixed ligands [biphenyl-4,4'-dicarboxylic acid (H 2bpdc) and dipyrido[3,2-d:2',3'-f]quinoxaline (Dpq)], and structurally characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction analysis. The unique feature is that there simultaneously exist two kinds of one-dimensional (1-D) zigzag polymeric chains in complex 1. Moreover, the 1-D polymeric chains are ultimately packed into a three-dimensional (3-D) supramolecular framework through two different hydrogen bonding interactions. The adjacent different chains are linked by C-H⋯O hydrogen bonding interactions, and the same kind chains are further connected through C-H⋯π stacking interactions. Additionally, the complex 1 was used as solid bulk-modifier to fabricate renewable carbon paste electrode (Cu-CPE) by the direct mixing method. The electrochemical behavior and electrocatalysis of Cu-CPE have been studied in detail. The results indicate that Cu-CPE give one-electron quasi-reversible redox waves in potential range of 400 to -300 mV due to the metal copper ion Cu(II)/Cu(I). The Cu-CPE showed good electrocatalytic activity toward the reduction of the bromate, nitrite and hydrogen peroxide. The electrocatalytic reduction peak currents of KBrO 3, KNO 2 and H 2O 2 showed a linear dependence on their concentrations. All of the results revealed that the Cu-CPE had a good reproducibility, remarkable long-term stability and especially good surface renewability by simple mechanical polishing in the event of surface fouling, which is important for practical application.

  6. WAY-855 (3-amino-tricyclo[2.2.1.02.6]heptane-1,3-dicarboxylic acid): a novel, EAAT2-preferring, nonsubstrate inhibitor of high-affinity glutamate uptake

    PubMed Central

    Dunlop, John; Eliasof, Scott; Stack, Gary; McIlvain, H Beal; Greenfield, Alexander; Kowal, Dianne; Petroski, Robert; Carrick, Tikva

    2003-01-01

    The pharmacological profile of a novel glutamate transport inhibitor, WAY-855 (3-amino-tricyclo[2.2.1.02.6]heptane-1,3-dicarboxylic acid), on the activity of the human forebrain glutamate transporters EAAT1, EAAT2 and EAAT3 expressed in stable mammalian cell lines and in Xenopus laevis oocytes is presented. WAY-855 inhibited glutamate uptake mediated by all three subtypes in a concentration-dependent manner, with preferential inhibition of the CNS-predominant EAAT2 subtype in both cells and oocytes. IC50 values for EAAT2 and EAAT3 inhibition in cells were 2.2 and 24.5 μM, respectively, while EAAT1 activity was inhibited by 50% at 100 μM (IC50 values determined in oocytes were 1.3 μM (EAAT2), 52.5 μM (EAAT3) and 125.9 μM (EAAT1)). Application of WAY-855 to EAAT-expressing oocytes failed to induce a transporter current, and the compound failed to exchange with accumulated [3H]D-aspartate in synaptosomes consistent with a nonsubstrate inhibitor. WAY-855 inhibited D-aspartate uptake into cortical synaptosomes by a competitive mechanism, and with similar potency to that observed for the cloned EAAT2. WAY-855 failed to agonise or antagonise ionotropic glutamate receptors in cultured hippocampal neurones, or the human metabotropic glutamate receptor subtype 4 expressed in a stable cell line. WAY-855 represents a novel structure in glutamate transporter pharmacology, and exploration of this structure might provide insights into the discrimination between EAAT2 and other EAAT subtypes. PMID:14517179

  7. Model pharmaceutical co-crystallization: Guest-directed assembly of caffeine and aromatic tri-hydroxy and dicarboxylic acids into different heteromolecular hydrogen bonding networks in solid state

    NASA Astrophysics Data System (ADS)

    Mahapatra, Ajit Kumar; Sahoo, Prithidipa; Goswami, Shyamaprosad; Fun, Hoong-Kun

    2010-01-01

    Three model pharmaceutical caffeine-containing co-crystals of 1,3,5-trihydroxybenzene (phloroglucinol), isophthalic acid and 5-hydroxyisophthalic acid were synthesized and characterized via single-crystal X-ray diffraction. The three crystalline forms reported are an anhydrous co-crystal and other two are co-crystal hydrates. Also their binding properties were studied by UV-vis analysis. In each of these structures, an organised intermolecular hydrogen bonding motif was observed. A comparison of hydrogen bonding motifs in the crystal sheets was presented.

  8. C4-Dicarboxylic acid metabolism in bundle-sheath chloroplasts, mitochondria and strands of Eriochloa borumensis Hack., a phosphoenolpyruvate-carboxykinase type C4 species.

    PubMed

    Rathnam, C K; Edwards, G E

    1977-01-01

    C4-acid metabolism by isolated bundlesheath chloroplasts, mitochondria and strands of Eriochloa borumensis Hack., a phosphoennolpyruvate-carboxykinase (PEP-CK) species, was investigated. Aspartate, oxaloacetate (OAA) and malate were decarboxylated by strands with several-fold stimulation upon illumination. There was strictly light-dependent decarboxylation of OAA and malate by the chloroplasts, but the chloroplasts did not decarboxylate aspartate in light or dark. PEP was a primary product of OAA or malate decarboxylation by the chloroplasts and its formation was inhibited by 3-(3,4-dichlorophenyl)-1, 1-dimethylurea or NH4Cl. There was very little conversion of PEP to pyruvate by bundle-sheath chloroplasts, mitochondria or strands. Decarboxylation of the three C4-acids by mitochondria was light-independent. Pyruvate was the only product of mitochondrial metabolism of C4-acids, and was apparently transaminated in the cytoplasm since PEP and alanine were primarily exported out of the bundle-sheath strands. Light-dependent C4-acid decarboxylation by the chloroplasts is suggested to be through the PEP-CK, while the mitochondrial C4-acid decarboxylation may proceed through the NAD-malic enzyme (NAD-ME) system. In vivo both aspartate and malate are considered as transport metobolites from mesophyll to bundle-sheath cells in PEP-CK species. Aspartate would be metabolized by the mitochondria to OAA. Part of the OAA may be converted to malate and decarboxylated through NAD-ME, and part may be transported to the chloroplasts for decarboxylation through PEP-CK localized in the chloroplasts. Malate transported from mesophyll cells may serve as carboxyl donor to chloroplasts through the chloroplastic NAD-malate dehydrogenase and PEP-CK. Bundle-sheath strands and chloroplasts fixed (14)CO2 at high rates and exhibited C4-acid-dependent O2 evolution in the light. Studies with 3-mercaptopicolinic acid, a specific inhibitor of PEP-CK, have indicated that most (about 70%) of the OAA

  9. Condensation of anhydrides or dicarboxylic acids with compounds containing active methylene groups. Part 19: Condensation of phthalic and substituted phthalic anhydrides with benzoylacetic ester

    NASA Technical Reports Server (NTRS)

    Rotberg, Y. T.; Oshkaya, V. P.

    1985-01-01

    Phthalylbenzoylacetic ester and its nitro and halogen derivatives were prepared through condensation of phthalic anhydride, nitrophthalic anhydride, and phthalic halide anhydride with benzoylacetic ester in a solution of acetic anhydride and triethylamine. The condensation of hemipinic acid anhydride proceeds similarly, but under more drastic conditions. Derivatives of indan-1,3-dione are also formed, with a small yield, in the reaction of nitrophthalic anhydrides with benzoylacetic ester in the presence of increased quantities of triethylamine.

  10. Condensation of anhydrides or dicarboxylic acids with compounds containing active methylene groups. Part 1: Condensation of phthalic anhydride with acetoacetic and malonic ester

    NASA Technical Reports Server (NTRS)

    Oshkaya, V. P.; Vanag, G. Y.

    1985-01-01

    Phthalic anhydride was condensed with acetoacetic ester in acetic anhydride and triethylamine solution, and when phthalyl chloride was reacted with sodium acetoacetic ester compounds were formed of the phthalide and indandione series: phthalylacetoacetic ester and a derivative of indan-1,3-dione which after boiling with hydrochloric acid yielded indan-1,3-dione. Phthalylmalonic ester was obtained from phthalic anhydride and malonic ester in the presence of triethylamine.

  11. Metabolic profile of mephedrone: Identification of nor-mephedrone conjugates with dicarboxylic acids as a new type of xenobiotic phase II metabolites.

    PubMed

    Linhart, Igor; Himl, Michal; Židková, Monika; Balíková, Marie; Lhotková, Eva; Páleníček, Tomáš

    2016-01-01

    Metabolic profile of mephedrone (4-methylmethcathinone, 4-MMC), a frequently abused recreational drug, was determined in rats in vivo. The urine of rats dosed with a subcutaneous bolus dose of 20mg 4-MMC/kg was analysed by LC/MS. Ten phase I and five phase II metabolites were identified by comparison of their retention times and MS(2) spectra with those of authentic reference standards and/or with the MS(2) spectra of previously identified metabolites. The main metabolic pathway was N-demethylation leading to normephedrone (4-methylcathinone, 4-MC) which was further conjugated with succinic, glutaric and adipic acid. Other phase I metabolic pathways included oxidation of the 4-methyl group, carbonyl reduction leading to dihydro-metabolites and ω-oxidation at the position 3'. Five of the metabolites detected, namely, 4-carboxynormephedrone (4-carboxycathinone, 4-CC), 4-carboxydihydronormephedrone (4-carboxynorephedrine, 4-CNE), hydroxytolyldihydro-normephedrone (4-hydroxymethylnorephedrine, 4-OH-MNE) and conjugates of 4-MC with glutaric and adipic acid, have not been reported as yet. The last two conjugates represent a novel, hitherto unexploited, type of phase II metabolites in mammals together with an analogous succinic acid conjugate of 4-MC identified by Pozo et al. (2015). These conjugates might be potentially of great importance in the metabolism of other psychoactive amines.

  12. Toward biotechnological production of adipic acid and precursors from biorenewables.

    PubMed

    Polen, Tino; Spelberg, Markus; Bott, Michael

    2013-08-20

    Adipic acid is the most important commercial aliphatic dicarboxylic acid in the chemical industry and is primarily used for the production of nylon-6,6 polyamide. The current adipic acid market volume is about 2.6 million tons/y and the average annual demand growth rate forecast to stay at 3-3.5% worldwide. Hitherto, the industrial production of adipic acid is carried out by petroleum-based chemo-catalytic processes from non-renewable fossil fuels. However, in the past years, efforts were made to find alternative routes for adipic acid production from renewable carbon sources by biotechnological processes. Here we review the approaches and the progress made toward bio-based production of adipic acid. PMID:22824738

  13. Aqua-(pyridine-3-carb-oxy-lic acid-κN)(pyridine-2,6-dicarboxyl-ato-κO,N,O)copper(II) monohydrate.

    PubMed

    Chen, Ting Ting; Shang, Yan Fang; Xi, Xia; Zhang, Yue Hua; Wang, Nan Ping

    2011-06-01

    In the title Cu(II) complex, [Cu(C(7)H(3)NO(4))(C(6)H(5)NO(2))(H(2)O)]·H(2)O, the environment of the Cu(2+) ion is a distorted square pyramid with the axial site occupied by the O atom from the coordinated water mol-ecule and the square base formed by two O and two N atoms from the tridentate anion and the neutral monodentate pyridine-3-carboxylic acid ligand. O-H⋯O hydrogen bonds, as well as π-π inter-actions [centroid-centroid distance = 3.945 (3) Å] contribute to the stabilization of this structure. PMID:21754683

  14. Optical properties in the UV and visible spectral region of organic acids relevant to tropospheric aerosols

    NASA Astrophysics Data System (ADS)

    Lund Myhre, C. E.; Nielsen, C. J.

    2004-09-01

    Refractive and absorption indices in the UV and visible region of selected aqueous organic acids relevant to tropospheric aerosols are reported. The acids investigated are the aliphatic dicarboxylic acids oxalic, malonic, tartronic, succinic and glutaric acid. In addition we report data for pyruvic, pinonic, benzoic and phthalic acid. To cover a wide range of conditions we have investigated the aqueous organic acids at different concentrations spanning from highly diluted samples to concentrations close to saturation. The density of the investigated samples is reported and a parameterisation of the absorption and refractive index that allows the calculation of the optical constants of mixed aqueous organic acids at different concentrations is presented. The single scattering albedo is calculated for two size distributions using measured and a synthetic set of optical constants. The results show that tropospheric aerosols consisting of only these organic acids and water have a pure scattering effect.

  15. Optical properties in the UV and visible spectral region of organic acids relevant to tropospheric aerosols

    NASA Astrophysics Data System (ADS)

    Lund Myhre, C. E.; Nielsen, C. J.

    2004-06-01

    Refractive and absorption indices in the UV and visible region of selected aqueous organic acids relevant to tropospheric aerosols are reported. The acids investigated are the aliphatic dicarboxylic acids oxalic, malonic, tartronic, succinic and glutaric acid. In addition we report data for pyruvic, pinonic, benzoic and phthalic acid. To cover a wide range of conditions we have investigated the aqueous organic acids at different concentrations spanning from highly diluted samples to concentrations close to saturation. The density of the investigated samples is reported and a parameterisation of the absorption and refractive index that allows the calculation of the optical constants of mixed aqueous organic acids at different concentrations is presented. The single scattering albedo is calculated for two size distributions using measured and a synthetic set of optical constants. The results show that tropospheric aerosols consisting of only these organic acids and water have a pure scattering effect.

  16. Anaerobic digestion of aliphatic polyesters.

    PubMed

    Šmejkalová, Pavla; Kužníková, Veronika; Merna, Jan; Hermanová, Soňa

    2016-01-01

    Anaerobic processes for the treatment of plastic materials waste represent versatile and effective approach in environmental protection and solid waste management. In this work, anaerobic biodegradability of model aliphatic polyesters, poly(L-lactic acid) (PLA), and poly(ɛ-caprolactone) (PCL), in the form of powder and melt-pressed films with varying molar mass, was studied. Biogas production was explored in batch laboratory trials at 55 ± 1°C under a nitrogen atmosphere. The inoculum used was thermophilic digested sludge (total solids concentration of 2.9%) from operating digesters at the Central Waste Water Treatment Plant in Prague, Czech Republic. Methanogenic biodegradation of PCLs typically yielded from 54 to 60% of the theoretical biogas yield. The biodegradability of PLAs achieved from 56 to 84% of the theoretical value. High biogas yield (up to 677 mL/g TS) with high methane content (more than 60%), comparable with conventionally processed materials, confirmed the potential of polyester samples for anaerobic treatment in the case of their exploitation in agriculture or as a packaging material in the food industry.

  17. Anaerobic digestion of aliphatic polyesters.

    PubMed

    Šmejkalová, Pavla; Kužníková, Veronika; Merna, Jan; Hermanová, Soňa

    2016-01-01

    Anaerobic processes for the treatment of plastic materials waste represent versatile and effective approach in environmental protection and solid waste management. In this work, anaerobic biodegradability of model aliphatic polyesters, poly(L-lactic acid) (PLA), and poly(ɛ-caprolactone) (PCL), in the form of powder and melt-pressed films with varying molar mass, was studied. Biogas production was explored in batch laboratory trials at 55 ± 1°C under a nitrogen atmosphere. The inoculum used was thermophilic digested sludge (total solids concentration of 2.9%) from operating digesters at the Central Waste Water Treatment Plant in Prague, Czech Republic. Methanogenic biodegradation of PCLs typically yielded from 54 to 60% of the theoretical biogas yield. The biodegradability of PLAs achieved from 56 to 84% of the theoretical value. High biogas yield (up to 677 mL/g TS) with high methane content (more than 60%), comparable with conventionally processed materials, confirmed the potential of polyester samples for anaerobic treatment in the case of their exploitation in agriculture or as a packaging material in the food industry. PMID:27191559

  18. [Differences in the light-activation of NADP-dependent glyceraldehyde-3-phosphate dehydrogenase and of ribulose-5-phosphate kinase between plants containing the Calvin and those containing the C4-dicarboxylic acid pathway of photosynthetic carbon reduction].

    PubMed

    Steiger, E; Ziegler, I; Ziegler, H

    1971-06-01

    1. Preceding experiments had shown that irradiance of intact leaves or of isolated chloroplasts causes a reversible increase in the activity of NADP-GPD (Ziegler and Ziegler, 1965) as well as of ribulose-5-phosphate kinase (Latzko and Gibbs, 1969). Examination of several species which carry out the Calvin type of photosynthetic CO2 fixation (Vicia faba, Spinacia oleracea, Nicotiana tabacum, Avena sativa) now revealed that the dark level of NADP-GPD activity ranges between 300-400 μmol NADPH/mg chlorophyll·h; irradiance causes an activation to an turnover rate of 900-1600 μmol NADPH/mg chlorophyll·h. 2. The dark-level of ribulose-5-phosphate kinase in these Calvin type plants corresponds to about 400 \\gmmol PO4---/mg chlorophyll\\sdh. It rises to 900\\2-1300 \\gmmol PO4---/mg chlorophyll\\sdh after irradiance. 3. In all species examined which carry out the C4-dicarboxylic acid type of CO2 fixation (Zea mays, Cyperus rotundus, Portulacca oleracea, Saccharum officinarum) the dark-level of NADP-GPD as well as of ribulose-5-phosphate kinase is already as high as the light-level of Calvin type plants. In these species irradiance either activates both enzymes only to a small extent (Saccharum officinarum, Portulacea oleracea) or it activates only one of the two enzymes to an exceptional high activity (NADP-GPD in Zea mays, ribulose-5-phosphate kinase in Cyperus rotundus), while the activity of the other one remains nearly constant. 4. The dark-level of NADP-GPD in young Zea mays (2 leaves expanded) is as high as in adult plants; moreover its further activation by light corresponds to that in adult plants. In contrast, the dark-activity of ribulose-5-phosphate kinase in young Zea mays corresponds to the lower level found in Calvin type plants and is activated by irradiance in the same manner as it is in the latter plants. 5. The activity of ribose-5-phosphate isomerase is not influenced by light.

  19. New insight on aliphatic linkages in the macromolecular organic fraction of Orgueil and Murchison meteorites through ruthenium tetroxide oxidation

    NASA Astrophysics Data System (ADS)

    Remusat, Laurent; Derenne, Sylvie; Robert, François

    2005-09-01

    Ruthenium tetroxide oxidation was used to examine the macromolecular insoluble organic matter (IOM) from the Orgueil and Murchison meteorites and especially to characterize the aliphatic linkages. Already applied to various terrestrial samples, ruthenium tetroxide is a selective oxidant which destroys aromatic units, converting them into CO 2, and yields aliphatic and aromatic acids. In our experiment on chondritic IOM, it produces mainly short aliphatic diacids and polycarboxylic aromatic acids. Some short hydroxyacids are also detected. Aliphatic diacids are interpreted as aliphatic bridges between aromatic units in the chemical structure, and polycarboxylic aromatic acids are the result of the fusion of polyaromatic units. The product distribution shows that aliphatic links are short with numerous substitutions. No indigenous monocarboxylic acid was detected, showing that free aliphatic chains must be very short (less than three carbon atoms). The hydroxyacids are related to the occurrence of ester and ether functional groups within the aliphatic bridges between the aromatic units. This technique thus allows us to characterize in detail the aliphatic linkages of the IOMs, and the derived conclusions are in agreement with spectroscopic, pyrolytic, and degradative results previously reported. Compared to terrestrial samples, the aliphatic part of chondritic IOM is shorter and highly substituted. Aromatic units are smaller and more cross-linked than in coals, as already proposed from NMR data. Orgueil and Murchison IOM exhibit some tiny differences, especially in the length of aliphatic chains.

  20. Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

    PubMed Central

    Bassanini, Ivan; Hult, Karl

    2015-01-01

    Summary Dicarboxylic acids and their derivatives (esters and anhydrides) have been used as acylating agents in lipase-catalyzed reactions in organic solvents. The synthetic outcomes have been dimeric or hybrid derivatives of bioactive natural compounds as well as functionalized polyesters. PMID:26664578

  1. Thermodynamics of Boroxine Formation from the Aliphatic Boronic Acid Monomers R–B(OH)2 (R = H, H3C, H2N, HO, and F): A Computational Investigation

    PubMed Central

    Bhat, Krishna L.; Markham, George D.; Larkin, Joseph D.; Bock, Charles W.

    2011-01-01

    Boroxines are the 6-membered cyclotrimeric dehydration products of organoboronic acids: 3 R– B(OH)2 → R3B3O3 + 3 H2O, and in recent years have emerged as a useful class of organoboron molecules with applications in organic synthesis both as reagents and catalysts, as structural components in boronic acid derived pharmaceutical agents, as anion acceptors and electrolyte additives for battery materials [AL Korich and PM Iovine, Dalton Trans. 39 (2010) 1423–1431]. Second-order Møller-Plesset perturbation theory, in conjunction with the Dunning-Woon correlation-consistent cc-pVDZ, aug-cc-pVDZ, cc-pVTZ, and aug-cc-pVTZ basis sets, was used to investigate the structures and relative energies of the endo-exo, anti, and syn conformers of the aliphatic boronic acids R–B(OH)2 (R = H, H3C, H2N, HO, and F), as well as the thermodynamics of their boroxine formation; single-point calculations at the MP2/aug-cc-pVQZ, MP2/aug-cc-pV5Z, and CCSD(T)/aug-cc-pVTZ level using the MP2/aug-cc-pVTZ optimized geometries were also performed in selected cases. The endo-exo conformer was generally lowest in energy in vacuo, as well as in PCM and CPCM models of aqueous and carbon tetrachloride media. The values of ΔH2980 for boroxine formation via dehydration from the endo-exo conformers of these aliphatic boronic acids ranged from −2.9 for (H2N)3B3O3 to +12.2 kcal/mol for H3B3O3 at the MP2/aug-cc-pVTZ level in vacuo; for H3B3O3 the corresponding values in PCM:UFF implicit carbon tetrachloride and aqueous media were +11.2 and +9.8 kcal/mol, respectively. Based on our calculations, we recommend that ΔHf(298 K) for boroxine listed in the JANAF compilation needs to be revised from −290.0 kcal/mol to approximately −277.0 kcal/mol. PMID:21650154

  2. The unusual canangafruticosides A-E: five monoterpene glucosides, two monoterpenes and a monoterpene glucoside diester of the aryldihydronaphthalene lignan dicarboxylic acid from leaves of Cananga odorata var. fruticosa.

    PubMed

    Nagashima, Jiro; Matsunami, Katsuyoshi; Otsuka, Hideaki; Lhieochaiphant, Duangporn; Lhieochaiphant, Sorasak

    2010-09-01

    From the leaves of Cananga odorata var. fruticosa, five unusual monoterpene glucosides, named canangafruticosides A-E (1-5), along with two unusual non-glucosidic monoterpenes (6, 7) were isolated. An aryldihydronaphthalene-type lignan dicarboxylate (8) was also isolated, with two moles of canangafruticoside A (1) on its ester moiety. This lignan also showed strong blue fluorescence emission under basic conditions. The structures of these compounds were elucidated by means of spectroscopic methods, with their absolute configurations determined by application of the modified Mosher's method to a compound chemically derived from canangafruticoside E. PMID:20619865

  3. Cloud condensation nuclei (CCN) activity of aliphatic amine secondary aerosol

    NASA Astrophysics Data System (ADS)

    Tang, X.; Price, D.; Praske, E.; Vu, D. N.; Purvis-Roberts, K.; Silva, P. J.; Cocker, D. R., III; Asa-Awuku, A.

    2014-06-01

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g., hydroxyl radical and nitrate radical). The particle can contain both secondary organic aerosol (SOA) and inorganic salts. The ratio of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ, ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N2O5 (source of nitrate radical, NO3) contains less volatile compounds than the primary aliphatic amine (BA) aerosol. As relative humidity (RH) increases, inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. The humid BA + N2O5 aerosol products were found to be very sensitive to the temperature at which the measurements were made within the streamwise continuous-flow thermal gradient CCN counter; κ ranges from 0.4 to 0.7 dependent on the instrument supersaturation (ss) settings. The variance of the measured aerosol κ values indicates that simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems' κ ranges within 0.2 < κ < 0.7. This work indicates that aerosols formed via nighttime reactions with amines are likely to produce hygroscopic and volatile aerosol, whereas photochemical reactions with OH produce secondary organic aerosol of lower CCN activity. The contributions of semivolatile secondary organic and inorganic material from aliphatic amines must be considered for accurate hygroscopicity and CCN predictions from aliphatic amine systems.

  4. Synthesis, pharmacological characterization, and molecular modeling of heterobicyclic amino acids related to (+)-2-aminobicyclo[3.1.0] hexane-2,6-dicarboxylic acid (LY354740): identification of two new potent, selective, and systemically active agonists for group II metabotropic glutamate receptors.

    PubMed

    Monn, J A; Valli, M J; Massey, S M; Hansen, M M; Kress, T J; Wepsiec, J P; Harkness, A R; Grutsch, J L; Wright, R A; Johnson, B G; Andis, S L; Kingston, A; Tomlinson, R; Lewis, R; Griffey, K R; Tizzano, J P; Schoepp, D D

    1999-03-25

    As part of our ongoing research program aimed at the identification of highly potent, selective, and systemically active agonists for group II metabotropic glutamate (mGlu) receptors, we have prepared novel heterobicyclic amino acids (-)-2-oxa-4-aminobicyclo[3.1. 0]hexane-4,6-dicarboxylate (LY379268, (-)-9) and (-)-2-thia-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate (LY389795, (-)-10). Compounds (-)-9 and (-)-10 are structurally related to our previously described nanomolar potency group II mGlu receptor agonist, (+)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylate monohydrate (LY354740 monohydrate, 5), with the C4-methylene unit of 5 being replaced with either an oxygen atom (as in (-)-9) or a sulfur atom (as in (-)-10). Compounds (-)-9 and (-)-10 potently and stereospecifically displaced specific binding of the mGlu2/3 receptor antagonist ([3H]LY341495) in rat cerebral cortical homogenates, displaying IC50 values of 15 +/- 4 and 8.4 +/- 0.8 nM, respectively, while having no effect up to 100 000 nM on radioligand binding to the glutamate recognition site on NMDA, AMPA, or kainate receptors. Compounds (-)-9 and (-)-10 also potently displaced [3H]LY341495 binding from membranes expressing recombinant human group II mGlu receptor subtypes: (-)-9, Ki = 14.1 +/- 1.4 nM at mGlu2 and 5.8 +/- 0.64 nM at mGlu3; (-)-10, Ki = 40.6 +/- 3.7 nM at mGlu2 and 4.7 +/- 1.2 nM at mGlu3. Evaluation of the functional effects of (-)-9 and (-)-10 on second-messenger responses in nonneuronal cells expressing human mGlu receptor subtypes demonstrated each to be a highly potent agonist for group II mGlu receptors: (-)-9, EC50 = 2.69 +/- 0.26 nM at mGlu2 and 4.58 +/- 0.04 nM at mGlu3; (-)-10, EC50 = 3.91 +/- 0.81 nM at mGlu2 and 7.63 +/- 2. 08 nM at mGlu3. In contrast, neither compound (up to 10 000 nM) displayed either agonist or antagonist activity in cells expressing recombinant human mGlu1a, mGlu5a, mGlu4a, or mGlu7a receptors. The agonist effects of (-)-9 and (-)-10 at group II m

  5. 40 CFR 721.3364 - Aliphatic ether.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aliphatic ether. 721.3364 Section 721... Aliphatic ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aliphatic ether (PMN P-93-1381) is subject to reporting under...

  6. 40 CFR 721.3364 - Aliphatic ether.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aliphatic ether. 721.3364 Section 721... Aliphatic ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aliphatic ether (PMN P-93-1381) is subject to reporting under...

  7. Aliphatic hydrocarbons of the Murchison meteorite

    SciTech Connect

    Cronin, J.R.; Pizzarello, S. )

    1990-10-01

    The indigenous organic compounds of carbonaceous chondrites have been difficult to characterize because of problems arising from terrestrial contamination. The fall of the Murchison meteorite (CM2) provided pristine samples which allowed the resolution of some prior ambiguities as, for example, in the case of the amino acids. However, the nature of the aliphatic hydrocarbons has remained unclear. Shortly after the Murchison fall, one laboratory found them to be mainly cycloalkanes; another found, in order of abundance, branched alkanes, olefins, and cycloalkanes; while a third reported predominantly n-alkanes followed by methyl alkanes and olefins. The authors have reinvestigated this question using benzene-methanol as the extraction solvent, silica-gel chromatography for fractionation of the extract, and GC-MS, and IR and NMR spectroscopic techniques for the analyses. When interior samples were obtained and the analyses carried out under conditions that minimized environmental contaminants, they have found the principal aliphatic components of the Murchison meteorite to be a structurally diverse suite of C{sub 15} to C{sub 30} branched alkyl-substituted mono-, di-, and tricyclic alkanes. Comparative analyses were carried out on the Murray (CM2), Allende (CV3), and New Concord (L6) chondrites that illustrate the nature of the contamination problem encountered with carbonaceous chondrites.

  8. Aliphatic hydrocarbons of the Murchison meteorite.

    PubMed

    Cronin, J R; Pizzarello, S

    1990-01-01

    The indigenous organic compounds of carbonaceous chondrites have been difficult to characterize because of problems arising from terrestrial contamination. The fall of the Murchison meteorite (CM2) provided pristine samples which allowed the resolution of some prior ambiguities as, for example, in the case of the amino acids. However, the nature of the aliphatic hydrocarbons has remained unclear. Shortly after the Murchison fall, one laboratory found them to be mainly cycloalkanes; another found, in order of abundance, branched alkanes, olefins, and cycloalkanes; while a third reported predominantly n-alkanes followed by methyl alkanes and olefins. We have reinvestigated this question using benzene-methanol as the extraction solvent, silica-gel chromatography for fractionation of the extract, and GC-MS, and IR and NMR spectroscopic techniques for the analyses. When interior samples were obtained and the analyses carried out under conditions that minimized environmental contaminants, we have found the principal aliphatic components of the Murchison meteorite to be a structurally diverse suite of C15 to C30 branched alkyl-substituted mono-, di-, and tricyclic alkanes. Comparative analyses were carried out on the Murray (CM2), Allende (CV3), and New Concord (L6) chondrites that illustrate the nature of the contamination problem encountered with carbonaceous chondrites.

  9. Guided desaturation of unactivated aliphatics

    NASA Astrophysics Data System (ADS)

    Voica, Ana-Florina; Mendoza, Abraham; Gutekunst, Will R.; Fraga, Jorge Otero; Baran, Phil S.

    2012-08-01

    The excision of hydrogen from an aliphatic carbon chain to produce an isolated olefin (desaturation) without overoxidation is one of the most impressive and powerful biosynthetic transformations for which there are no simple and mild laboratory substitutes. The versatility of olefins and the range of reactions they undergo are unsurpassed in functional group space. Thus, the conversion of a relatively inert aliphatic system into its unsaturated counterpart could open new possibilities in retrosynthesis. In this article, the invention of a directing group to achieve such a transformation under mild, operationally simple, metal-free conditions is outlined. This ‘portable desaturase’ (TzoCl) is a bench-stable, commercial entity (Aldrich, catalogue number L510092) that is facile to install on alcohol and amine functionalities to ultimately effect remote desaturation, while leaving behind a synthetically useful tosyl group.

  10. Guided Desaturation of Unactivated Aliphatics

    PubMed Central

    Voica, Ana-Florina; Mendoza, Abraham; Gutekunst, Will R.; Fraga, Jorge Otero; Baran, Phil S.

    2012-01-01

    The excision of hydrogen from an aliphatic carbon chain to produce an isolated olefin (desaturation) without over-oxidation is one of the most impressive and powerful biosynthetic transformations for which there are no simple and mild laboratory substitutes. The versatility of olefins and the range of reactions they undergo is unsurpassed in functional group space. Thus, the conversion of a relatively inert aliphatic system to its unsaturated counterpart can open new possibilities in retrosynthesis. In this article, the invention of a directing group to achieve such a transformation under mild, operationally simple, metal-free conditions is outlined. This “portable desaturase” (TzoCl) is a bench-stable, commercial entity (Aldrich, cat # L510092) that is facile to install on alcohol and amine functionalities to ultimately effect remote desaturation, while leaving behind a synthetically useful tosyl group. PMID:22824894

  11. Scope and limitations of aliphatic Friedel-Crafts alkylations. Lewis acid catalyzed addition reactions of alkyl chlorides to carbon-carbon double bonds

    SciTech Connect

    Mayr, H.; Striepe, W.

    1983-04-22

    Lewis acid catalyzed addition reactions of alkyl halides with unsaturated hydrocarbons have been studied. 1:1 addition products are formed if the addends dissociate faster than the corresponding products; otherwise, polymerization takes place. For reaction conditions under which these compounds exist mainly undissociated, solvolysis constants of model compounds can be used to predict the outcome of any such addition reactions if systems with considerable steric hindrance are excluded.

  12. Aliphatic hydrocarbons of the fungi.

    NASA Technical Reports Server (NTRS)

    Weete, J. D.

    1972-01-01

    Review of studies of aliphatic hydrocarbons which have been recently detected in the spores of phytopathogenic fungi, and are found to be structurally very similar to the alkanes of higher plants. It appears that the hydrocarbon components of the few mycelial and yeast forms reported resemble the distribution found in bacteria. The occurence and distribution of these compounds in the fungi is discussed. Suggested functional roles of fungal spore alkanes are presented.

  13. Dicarboxylic acids, oxoacids, benzoic acid, α-dicarbonyls, WSOC, OC, and ions in spring aerosols from Okinawa Island in the western North Pacific Rim: size distributions and formation processes

    NASA Astrophysics Data System (ADS)

    Deshmukh, D. K.; Kawamura, K.; Lazaar, M.; Kunwar, B.; Boreddy, S. K. R.

    2015-09-01

    Size-segregated aerosols (9-stages from < 0.43 to > 11.3 μm in diameter) were collected at Cape Hedo, Okinawa in spring 2008 and analyzed for water-soluble diacids (C2-C12), ω-oxoacids (ωC2-ωC9), pyruvic acid, benzoic acid and α-dicarbonyls (C2-C3) as well as water-soluble organic carbon (WSOC), organic carbon (OC) and major ions. In all the size-segregated aerosols, oxalic acid (C2) was found as the most abundant species followed by malonic and succinic acids whereas glyoxylic acid (ωC2) was the dominant oxoacid and glyoxal (Gly) was more abundant than methylglyoxal. Diacids (C2-C5), ωC2 and Gly as well as WSOC and OC peaked at 0.65-1.1 μm in fine mode whereas azelaic (C9) and 9-oxononanoic (ωC9) acids peaked at 3.3-4.7 μm in coarse mode. Sulfate and ammonium are enriched in fine mode whereas sodium and chloride are in coarse mode. These results imply that water-soluble species in the marine aerosols could act as cloud condensation nuclei (CCN) to develop the cloud cover over the western North Pacific Rim. The organic species are likely produced by a combination of gas-phase photooxidation, and aerosol-phase or in-cloud processing during long-range transport. The coarse mode peaks of malonic and succinic acids were obtained in the samples with marine air masses, suggesting that they may be associated with the reaction on sea salt particles. Bimodal size distributions of longer-chain diacid (C9) and oxoacid (ωC9) with a major peak in the coarse mode suggest their production by photooxidation of biogenic unsaturated fatty acids via heterogeneous reactions on sea salt particles.

  14. Pharmacological and pharmacokinetic properties of a structurally novel, potent, and selective metabotropic glutamate 2/3 receptor agonist: in vitro characterization of agonist (-)-(1R,4S,5S,6S)-4-amino-2-sulfonylbicyclo[3.1.0]-hexane-4,6-dicarboxylic acid (LY404039).

    PubMed

    Rorick-Kehn, Linda M; Johnson, Bryan G; Burkey, Jennifer L; Wright, Rebecca A; Calligaro, David O; Marek, Gerard J; Nisenbaum, Eric S; Catlow, John T; Kingston, Ann E; Giera, Deborah D; Herin, Marc F; Monn, James A; McKinzie, David L; Schoepp, Darryle D

    2007-04-01

    Group II metabotropic glutamate (mGlu) receptor agonists, including (1S,2S,5R,6S)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylate monohydrate (LY354740) and (-)-2-oxa-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate (LY379268), have demonstrated efficacy in animal models of anxiety and schizophrenia, and LY354740 decreased anxiety in human subjects. Herein, we report the in vitro pharmacological profile and pharmacokinetic properties of another potent, selective, and structurally novel mGlu2/3 receptor agonist, (-)-(1R,4S,5S,6S)-4-amino-2-sulfonylbicyclo[3.1.0]hexane-4,6-dicarboxylic acid (LY404039) and provide comparisons with LY354740. Similar to LY354740, LY404039 is a nanomolar potent agonist at recombinant human mGlu2 and mGlu3 receptors (K(i) = 149 and 92, respectively) and in rat neurons expressing native mGlu2/3 receptors (Ki = 88). LY404039 is highly selective for mGlu2/3 receptors, showing more than 100-fold selectivity for these receptors, versus ionotropic glutamate receptors, glutamate transporters, and other receptors targeted by known anxiolytic and antipsychotic medications. Functionally, LY404039 potently inhibited forskolin-stimulated cAMP formation in cells expressing human mGlu2 and mGlu3 receptors. Electrophysiological studies indicated that LY404039 suppressed electrically evoked excitatory activity in the striatum, and serotonin-induced l-glutamate release in the prefrontal cortex; effects reversed by LY341495. These characteristics suggest LY404039 modulates glutamatergic activity in limbic and forebrain areas relevant to psychiatric disorders; and that, similar to LY354740, it works through a mechanism that may be devoid of negative side effects associated with current antipsychotics and anxiolytics. Interestingly, despite the slightly lower potency (approximately 2-5-fold) of LY404039 versus LY354740 in binding, functional, and electrophysiological assays, LY404039 demonstrated higher plasma exposure and better oral bioavailability in

  15. Time-resolved FT EPR and optical spectroscopy study on photooxidation of aliphatic alpha-amino acids in aqueous solutions; electron transfer from amino vs carboxylate functional group.

    PubMed

    Tarabek, Peter; Bonifacić, Marija; Beckert, Dieter

    2006-06-01

    Using time-resolved Fourier transform electron paramagnetic resonance, FT EPR, and optical spectroscopy, the photooxidation of glycine, alpha-alanine, alpha-aminoisobutyric acid, and model compounds beta-alanine, methylamine and sodium acetate, by excited triplets of anthraquinone-2,6-disulfonate dianion was studied in aqueous solutions in the pH range 5-13. Anthraquinone radical trianions showing strong emissive spin-polarization (CIDEP) were formed, indicating fast electron transfer from the quenchers to the spin-polarized quinone triplet as the primary reaction. None of the primary radicals formed upon one-electron oxidation of quenchers could be detected at the nanosecond time scale of FT EPR measurements because of their very fast transformation into secondary products. The latter were identified to be decarboxylated alpha-aminoalkyl radicals for alpha-amino acids anions and zwitterions, beta-aminoalkyl radicals for beta-alanine zwitterions, and methyl radicals for acetate anions; corresponding aminyl radicals were the first EPR detectable products from beta-alanine anions and methylamine. Thus, anthraquinone-2,6-disulfonate triplet can take an electron from both NH(2)- and -CO(2)(-) functional groups forming aminium ((+*)NH(2)-) and acyloxyl (-CO(2)(*)) radicals, respectively. Aminium radicals derived from beta-alanine anions and CH(3)-NH(2) stabilize by deprotonation into aminyl radicals, whereas these derived from alpha-amino acids anions are known to suffer ultrafast decarboxylation (tau approximately 10 ps). Analysis of the polarization patterns revealed that decarboxylation from acyloxyl radicals are considerably slower (ns < tau < 0.1 micros). Therefore, in the case of alpha-amino acids, the isoelectronic structures NH(2)-CR(2)-CO(2)(*) and (+*)NH(2)-CR(2)-CO(2)(-) probably do not constitute resonance mesomeric forms of one and the same species and the decarboxylation of aminium radicals is not preceded by the intramolecular carboxylate to amino group

  16. Dicarboxylic acids, oxoacids, benzoic acid, α-dicarbonyls, WSOC, OC, and ions in spring aerosols from Okinawa Island in the western North Pacific Rim: size distributions and formation processes

    NASA Astrophysics Data System (ADS)

    Deshmukh, Dhananjay K.; Kawamura, Kimitaka; Lazaar, Manuel; Kunwar, Bhagawati; Boreddy, Suresh K. R.

    2016-04-01

    Size-segregated aerosols (nine stages from < 0.43 to > 11.3 µm in diameter) were collected at Cape Hedo, Okinawa, in spring 2008 and analyzed for water-soluble diacids (C2-C12), ω-oxoacids (ωC2-ωC9), pyruvic acid, benzoic acid, and α-dicarbonyls (C2-C3) as well as water-soluble organic carbon (WSOC), organic carbon (OC), and major ions (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3-, SO42-, and MSA-). In all the size-segregated aerosols, oxalic acid (C2) was found to be the most abundant species, followed by malonic and succinic acids, whereas glyoxylic acid (ωC2) was the dominant oxoacid and glyoxal (Gly) was more abundant than methylglyoxal. Diacids (C2-C5), ωC2, and Gly as well as WSOC and OC peaked at fine mode (0.65-1.1 µm) whereas azelaic (C9) and 9-oxononanoic (ωC9) acids peaked at coarse mode (3.3-4.7 µm). Sulfate and ammonium were enriched in fine mode, whereas sodium and chloride were in coarse mode. Strong correlations of C2-C5 diacids, ωC2 and Gly with sulfate were observed in fine mode (r = 0.86-0.99), indicating a commonality in their secondary formation. Their significant correlations with liquid water content in fine mode (r = 0.82-0.95) further suggest an importance of the aqueous-phase production in Okinawa aerosols. They may also have been directly emitted from biomass burning in fine mode as supported by strong correlations with potassium (r = 0.85-0.96), which is a tracer of biomass burning. Bimodal size distributions of longer-chain diacid (C9) and oxoacid (ωC9) with a major peak in the coarse mode suggest that they were emitted from the sea surface microlayers and/or produced by heterogeneous oxidation of biogenic unsaturated fatty acids on sea salt particles.

  17. Development of aliphatic biodegradable photoluminescent polymers

    PubMed Central

    Yang, Jian; Zhang, Yi; Gautam, Santosh; Liu, Li; Dey, Jagannath; Chen, Wei; Mason, Ralph P.; Serrano, Carlos A.; Schug, Kevin A.; Tang, Liping

    2009-01-01

    None of the current biodegradable polymers can function as both implant materials and fluorescent imaging probes. The objective of this study was to develop aliphatic biodegradable photoluminescent polymers (BPLPs) and their associated cross-linked variants (CBPLPs) for biomedical applications. BPLPs are degradable oligomers synthesized from biocompatible monomers including citric acid, aliphatic diols, and various amino acids via a convenient and cost-effective polycondensation reaction. BPLPs can be further cross-linked into elastomeric cross-linked polymers, CBPLPs. We have shown representatively that BPLP-cysteine (BPLP-Cys) and BPLP-serine (BPLP-Ser) offer advantages over the traditional fluorescent organic dyes and quantum dots because of their preliminarily demonstrated cytocompatibility in vitro, minimal chronic inflammatory responses in vivo, controlled degradability and high quantum yields (up to 62.33%), tunable fluorescence emission (up to 725 nm), and photostability. The tensile strength of CBPLP-Cys film ranged from 3.25 ± 0.13 MPa to 6.5 ± 0.8 MPa and the initial Modulus was in a range of 3.34 ± 0.15 MPa to 7.02 ± 1.40 MPa. Elastic CBPLP-Cys could be elongated up to 240 ± 36%. The compressive modulus of BPLP-Cys (0.6) (1:1:0.6 OD:CA:Cys) porous scaffold was 39.60 ± 5.90 KPa confirming the soft nature of the scaffolds. BPLPs also possess great processability for micro/nano-fabrication. We demonstrate the feasibility of using BPLP-Ser nanoparticles (“biodegradable quantum dots”) for in vitro cellular labeling and noninvasive in vivo imaging of tissue engineering scaffolds. The development of BPLPs and CBPLPs represents a new direction in developing fluorescent biomaterials and could impact tissue engineering, drug delivery, bioimaging. PMID:19506254

  18. Insights into the supramolecular features in isopropylmalonic and n-butylmalonic acids: Inputs from PIXEL and Hirshfeld surface analysis

    NASA Astrophysics Data System (ADS)

    Dey, Dhananjay; Mondal, Ranjan Kumar; Dhibar, Subhendu; Lin, Chia-Her; Schollmeyer, Dieter; Chopra, Deepak; Dey, Biswajit

    2016-10-01

    In this study, we have investigated the supramolecular pattern in two dicarboxylic acids, namely isopropylmalonic acid (1) and n-butylmalonic acid (2), via the presence of different hydrogen bonding patterns and aliphatic chains associated with the respective acids. The crystal structure is formed via the presence of strong Osbnd H⋯O and Csbnd H⋯O H-bonds, in the solid-state. The nature and energetics of the different supramolecular architectures in these two molecules have been further analyzed quantitatively via the PIXEL method. Hirshfeld surface analysis and fingerprint plots help to evaluate the contribution of different types of intermolecular contacts in the crystal packing. MESP calculations have been done to delineate the negative and positive areas of the electrostatic potential in different regions of the molecule in the crystal environment.

  19. A new redox-active coordination polymer with cobalticinium dicarboxylate.

    PubMed

    Kondo, Mitsuru; Hayakawa, Yuri; Miyazawa, Makoto; Oyama, Aiko; Unoura, Kei; Kawaguchi, Hiroyuki; Naito, Tetsuyoshi; Maeda, Kenji; Uchida, Fumio

    2004-09-20

    A new two-dimensional coordination polymer with cobalticinium 1,1'-dicarboxylate (ccdc) incorporated in the framework has been prepared, the ccdc functioning as unique monoanionic dicarboxylate ligands. The compound shows a high redox activity based on the ccdc units.

  20. Evidence for the role of metabotropic glutamate (mGlu)2 not mGlu3 receptors in the preclinical antipsychotic pharmacology of the mGlu2/3 receptor agonist (-)-(1R,4S,5S,6S)-4-amino-2-sulfonylbicyclo[3.1.0]hexane-4,6-dicarboxylic acid (LY404039).

    PubMed

    Fell, Matthew J; Svensson, Kjell A; Johnson, Bryan G; Schoepp, Darryle D

    2008-07-01

    (-)-(1R,4S,5S,6S)-4-amino-2-sulfonylbicyclo[3.1.0]hexane-4,6-dicarboxylic acid (LY404039) is a potent and selective group II metabotropic glutamate [(mGlu)2 and mGlu3] receptor agonist for which its prodrug LY2140023 [(1R,4S,5S,6S)-2-thiabicyclo[3.1.0]-hexane-4,6-dicarboxylic acid,4-[(2S)-2-amino-4-(methylthio)-1-oxobutyl]amino-, 2,2-dioxide monohydrate] has recently been shown to have efficacy in the treatment of the positive and negative symptoms of schizophrenia. In this article, we use mGlu receptor-deficient mice to investigate the relative contribution of mGlu2 and mGlu3 receptors in mediating the antipsychotic profile of LY404039 in the phencyclidine (PCP) and d-amphetamine (AMP) models of psychosis. To further explore the mechanism of action of LY404039, we compared the drugs' ability to block PCP-induced hyperlocomotion to that of atypical antipsychotics in wild-type and mice lacking mGlu2/3 receptors. In wild-type animals, LY404039 (3-30 mg/kg i.p.) significantly reversed AMP (5 mg/kg, i.p.)-induced increases in ambulations, distance traveled, and reduced time spent at rest. LY404039 reversed PCP (7.5 mg/kg i.p.)-evoked behaviors at 10 mg/kg. The antipsychotic-like effects of LY404039 (10 mg/kg i.p.) on PCP and AMP-evoked behavioral activation were absent in mGlu2 and mGlu2/3 but not in mGlu3 receptor-deficient mice, indicating that the activation of mGlu2 and not mGlu3 receptors is responsible for the antipsychotic-like effects of the mGlu2/3 receptor agonist LY404039. In contrast, the atypical antipsychotic drugs clozapine and risperidone inhibited PCP-evoked behaviors in both wild-type and mGlu2/3 receptor-deficient mice. These data demonstrate that the antipsychotic-like effects of the mGlu2/3 receptor agonist LY404039 in psychostimulant models of psychosis are mechanistically distinct from those of atypical antipsychotic drugs and are dependent on functional mGlu2 and not mGlu3 receptors. PMID:18424625

  1. Bacterial isolates degrading aliphatic polycarbonates.

    PubMed

    Suyama, T; Hosoya, H; Tokiwa, Y

    1998-04-15

    Bacteria that degrade an aliphatic polycarbonate, poly(hexamethylene carbonate), were isolated from river water in Ibaraki. Prefecture, Japan, after enrichment in liquid medium containing poly(hexamethylene carbonate) suspensions as carbon source, and dilution to single cells. Four of the strains, 35L, WFF52, 61A and 61B2, degraded poly(hexamethylene carbonate) on agar plate containing suspended poly(hexamethylene carbonate). Degradation of poly(hexamethylene carbonate) was confirmed by gel permeation chromatography. Besides poly(hexamethylene carbonate), the strains were found to degrade poly(tetramethylene carbonate). The strains were characterized morphologically, physiologically, and by 16S rDNA sequence analysis. Strains 35L and WFF52 were tentatively identified as Pseudomonas sp. and Variovorax sp., respectively, while strains 61A and 61B2 constitute an unidentified branch within the beta subclass of the Proteobacteria.

  2. Urinary toxicokinetics of di-(isononyl)-cyclohexane-1,2-dicarboxylate (DINCH(®)) in humans following single oral administration.

    PubMed

    Völkel, Wolfgang; Kiranoglu, Mandy; Dettbarn, Gerhard; John, Andrea; Jessel, Sönke; Seidel, Albrecht; Fromme, Hermann

    2016-04-25

    Phthalates such as di-2-ethylhexyl phthalate (DEHP) were restricted due to their toxic mainly reprotoxic effects. Therefore compounds such as di-(isononyl)-cyclohexane-1,2-dicarboxylate (DINCH(®)) substitute these phthalates and the exposure of humanes to substitutes may occur. Here, kinetic data are presented to assess the exposure of humans. Male and female volunteers excreted nearly the complete orally administered dose (1mg/kg b.w. corresponding to the tolerable daily intake of EFSA) of di-(isononyl)-cyclohexane-1,2-dicarboxylate within 70 h. More than 75% were excreted within 24h. Besides the main metabolite cyclohexane-1,2-dicarboxylic acid (CHDA) quantitated after hydrolysis four further metabolites of DINCH(®) are determined. Cyclohexane-1,2-dicarboxylic acid-mono-(7-hydroxy-4-methyl)octyl ester (OH-MINCH) is the main secondary metabolite with about 14% of the administered dose. Differences in excretion of all metabolites between male and females are small. Based on the generated toxicokinetic data exposure of 20 humans is recalculated from their spot urine sample collected in 2014 and the exposure are clearly below the current tolerable daily intake of 1mg/kg b.w.

  3. C6-C10-dicarboxylic aciduria: biochemical considerations in relation to diagnosis of beta-oxidation defects.

    PubMed

    Gregersen, N; Kølvraa, S; Mortensen, P B; Rasmussen, K

    1982-01-01

    By means of gas chromatographic methods substantial amounts of the C6-C10-dicarboxylic acids, i.e. adipic, suberic and sebacic acids, have been found in the urine from children with unexplained attacks of lethargy and hypotonia, presumably related to episodes of fever and/or insufficient food intake. The course have once been fatal and is often characterized by severe hypoglycemia without ketonuria. Systematic gas chromatographic/mass spectrometric determinations of selected organic acid metabolites in the urine, together with enzymatic measurements in fibroblasts and clinical data from 4 patients of this category, have shown that the biochemical basis of this syndrome can be inborn errors of the beta-oxidation of fatty acids, localized to the medium-chain acyl-CoA dehydrogenation system. The biosynthesis of adipic, suberic and sebacic acids was studied using ketotic rats as the model, since ketosis in rats and humans is accompanied by excessive urinary excretion of adipic and suberic acids. A probable pathway for the production of the three dicarboxylic acids was found to be an initial omega-oxidation of the medium-chain C10-C14-monocarboxylic acids followed by beta-oxidation of the resulting medium-chain dicarboxylic acids. It is argued that the source of the omega-oxidizable monocarboxylic acids in ketosis most probably is the fat deposites, and it is speculated that the patients with beta-oxidation defects supplement this source with beta-oxidation intermediate medium-chain monocarboxylic acids, accumulated as a result of the defect. The ratio between the excreted amounts of adipic acid and sebacic acid in the urine from the patients with beta-oxidation defects is less than 50. This is in contrast to the ratio in urine from ketotic patients, where it is greater than 100. Adipic acid/sebacic acid ratio-measured by means of a gas chromatographic analysis-is therefore suggested as a tool in the diagnosis of dicarboxylic acidurias. Based on the clinical picture and

  4. A Bio-Catalytic Approach to Aliphatic Ketones

    PubMed Central

    Xiong, Mingyong; Deng, Jin; Woodruff, Adam P.; Zhu, Minshan; Zhou, Jun; Park, Sun Wook; Li, Hui; Fu, Yao; Zhang, Kechun

    2012-01-01

    Depleting oil reserves and growing environmental concerns have necessitated the development of sustainable processes to fuels and chemicals. Here we have developed a general metabolic platform in E. coli to biosynthesize carboxylic acids. By engineering selectivity of 2-ketoacid decarboxylases and screening for promiscuous aldehyde dehydrogenases, synthetic pathways were constructed to produce both C5 and C6 acids. In particular, the production of isovaleric acid reached 32 g/L (0.22 g/g glucose yield), which is 58% of the theoretical yield. Furthermore, we have developed solid base catalysts to efficiently ketonize the bio-derived carboxylic acids such as isovaleric acid and isocaproic acid into high volume industrial ketones: methyl isobutyl ketone (MIBK, yield 84%), diisobutyl ketone (DIBK, yield 66%) and methyl isoamyl ketone (MIAK, yield 81%). This hybrid “Bio-Catalytic conversion” approach provides a general strategy to manufacture aliphatic ketones, and represents an alternate route to expanding the repertoire of renewable chemicals. PMID:22416247

  5. A combined experimental and DFT/TD-DFT investigation of structural, electronic, and cation-induced switching of photophysical properties of bimetallic Ru(II) and Os(II) complexes derived from imidazole-4,5-dicarboxylic acid and 2,2'-bipyridine.

    PubMed

    Das, Shyamal; Karmakar, Srikanta; Saha, Debasish; Baitalik, Sujoy

    2013-06-17

    Experimental results coupled with computational studies were utilized to investigate the structural and electronic properties of mixed-ligand bimetallic ruthenium(II) and osmium(II) complexes of composition [(bpy)2M(Imdc)M(bpy)2](+) [M = Ru(II) (1) and M = Os(II) (2)], where H3Imdc = imidazole-4,5-dicarboxylic acid and bpy = 2,2'-bipyridine. The X-ray crystal structures of both the bimetallic complexes were determined which showed that compound 1 crystallizes in monoclinic form with space group P2(1)/c, while 2 is obtained in orthorhombic form with the space group Pca2(1). The optimized geometrical parameters for the complexes computed both in the gas phase and in solution are reported and compared with the single-crystal X-ray data. The absorption spectra, redox behaviors, and luminescence properties of the complexes were thoroughly investigated. The complexes display very intense, ligand-centered absorption bands in the UV and moderately intense MLCT bands in the visible regions. While the Ru(II) complex displays moderately strong luminescence, the corresponding Os(II) complex does not luminesce at room temperature. Both the bimetallic complexes show two successive one-electron reversible metal-centered oxidations. The effect of alkali, alkaline earth, and transition metal cations on the absorption and emission spectral behavior of the complexes has also been studied in detail. As compared to the luminescence intensities and the quantum yields of the free complexes, those of the complexes were enhanced substantially in the presence of selective cations showing cation-induced molecular switching behaviors. Density functional theory (DFT) and time-dependent DFT (TD-DFT) studies provide insight into the nature of the ground and excited states with resulting detailed assignments of the orbitals involved in absorption and emission transitions. In particular, the blue-shifts of the absorption and emission bands in the presence of cations are also reproduced by our

  6. Syntheses and characterization of novel lanthanide adamantine-dicarboxylate coordination complexes

    SciTech Connect

    Li Xing; Wei Danyi; Huang Shijie; Zheng Yueqing

    2009-01-15

    Hydrothermal reactions of 1,10-phenanthroline (phen), 1,3-adamantanedicarboxylic acid (H{sub 2}L) and lanthanide chlorides yielded six compounds: [Ln(L)(HL)(phen)] (Ln=Pr, 1; Nd, 2), [Ln(L)(HL)(phen)(H{sub 2}O)] (Sm, 3; Eu, 4), [Tb(L)(HL)(phen)(H{sub 2}O)]{sub 2}.2H{sub 2}O (5), [Er{sub 3}(L){sub 4}(OH)(phen)]{sub 2} (6). Compounds 1-4 are structurally featured by one-dimensional polymeric chains; 5 hold binuclear structure constructed from eight-coordinated lanthanide center LnN{sub 2}O{sub 6} of distorted bicapped trigonal prism bridged by dicarboxylate ligands; 6 shows that erbium ions are in mono and bicapped trigonal prismatic geometries, respectively, which are further connected by {mu}{sub 3}-OH to give rise to trinuclear structure. Thermogravimetric analyses of 1, 3 and 5 were performed. Fluorescent measurements of 4 and 5 were carried out, respectively. - Grapical Abstract: Hydrothermal reactions of 1,10-phenanthroline, 1,3-adamantanedicarboxylic acid and lanthanide choloride yielded a novel supramolecular architectures constructed from polyhedral LnN{sub 2}O{sub 6} of distorted bicapped trigonal prism bridged by dicarboxylate.

  7. Mixed ligand two dimensional Cd(ii)/Ni(ii) metal organic frameworks containing dicarboxylate and tripodal N-donor ligands: Cd(ii) MOF is an efficient luminescent sensor for detection of picric acid in aqueous media.

    PubMed

    Rachuri, Yadagiri; Parmar, Bhavesh; Bisht, Kamal Kumar; Suresh, Eringathodi

    2016-05-01

    Two dimensional metal organic frameworks (MOFs) [Cd(5-BrIP)(TIB)]n () and [Ni2(5-BrIP)2(TIB)2]n (), involving the aromatic polycarboxylate ligand 5-bromo isophthalic acid (H2BrIP), flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)benzene (TIB) and Cd(ii)/Ni(ii) metal nodes have been synthesized by different methods. These compounds were characterized by various analytical methods, and variable temperature X-ray diffraction data showed thermal stability of both MOFs up to 350 °C. Phase purity as well as water stability of the MOFs were established by powder X-ray diffraction, and the structural diversity of the compounds were investigated by single-crystal X-ray diffraction. Both the MOFs are mixed ligand 2D nets, and the topology of the network can be described as a binodal 3,5-c connected net with 3,5L2 topology having the point symbol {4(2)·6(7)·8}{4(2)·6}. Sensing of picric acid [2,4,6-trinitrophenol, TNP] by luminescence quenching among a large range of nitroanalytes in aqueous phase by the Cd(ii) luminescent MOF (LMOF) were been investigated. Structural studies on 1 : 1 co-crystals () of TIB and TNP were carried out. The selective and sensitive fluorescence quenching response of towards electron-deficient TNP over other nitro analytes in aqueous phase was demonstrated by fluorescence quenching titration. Concomitant occurrence of electron transfer/energy transfer processes and electrostatic interaction favours the selective sensing of TNP. A Cd(ii) LMOF ()-coated paper strip that we developed demonstrated fast and selective response to TNP, by the complete quenching of the blue fluorescence upon excitation of the paper strip at 365 nm radiation in its presence. PMID:27067118

  8. Tuning structural dimensionalities of two new luminescent Cd(II) compounds: Different dicarboxylate coligands

    NASA Astrophysics Data System (ADS)

    Cao, Xiulian; Xing, Guang'en; Zhang, Yan

    2016-11-01

    Two new Cd(II) compounds, namely [Cd (tdc)(HPPA)]n·n (H2O) (1) and [Cd3 (obb)2(PPA)2(H2O)3]n (2) (H2tdc = 2,5-thiophenedicarboxylic acid, HPPA = pipemidic acid, H2oba = 4,4‧-oxybis (benzoate)), have been synthesized by incorporating pipemidic acid with Cd(II) ions and dicarboxylate coligands. Structural analyses reveal that compound 1 is a 1D chain structure, and further extended into a 2D supramolecular layered framework via intermolecular π…π and hydrogen bonding interactions, and compound 2 features a 3-fold interpenetrated 3D framework with 4-connected dia topology. HPPA ligand displays two different coordination modes in these two compounds. In addition, the thermal stabilities and luminescent properties of compounds 1 and 2 were also investigated in the solid state at room temperature.

  9. Selective Mono-reduction of Pyrrole-2,5 and 2,4-Dicarboxylates.

    PubMed

    Yasui, Eiko; Tsuda, Jyunpei; Ohnuki, Satoshi; Nagumo, Shinji

    2016-01-01

    Pyrrole-2,5-dicarboxylates were rapidly and selectively reduced to the corresponding mono-alcohol using 3 eq of diisobutylaluminum hydride at 0°C. Pyrrole-2,4-dicarboxylate showed the same reactivity; however, the selectivity decreased with pyrrole-3,4-dicarboxylate. When the nitrogen atom of the pyrrole-2,5-dicarboxylate is protected with a benzyl group, selective mono-reduction does not occur. Considering that furan-2,5-dicarboxylates did not give the corresponding mono-alcohol under the same conditions, the unprotected nitrogen atom of pyrrole apparently plays an important role in this selective mono-reduction. PMID:27581630

  10. 40 CFR 721.10534 - Brominated aliphatic alcohol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Brominated aliphatic alcohol (generic... Specific Chemical Substances § 721.10534 Brominated aliphatic alcohol (generic). (a) Chemical substance and... aliphatic alcohol (PMN P-12-260) is subject to reporting under this section for the significant new...

  11. 40 CFR 721.10534 - Brominated aliphatic alcohol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Brominated aliphatic alcohol (generic... Specific Chemical Substances § 721.10534 Brominated aliphatic alcohol (generic). (a) Chemical substance and... aliphatic alcohol (PMN P-12-260) is subject to reporting under this section for the significant new...

  12. 40 CFR 721.3520 - Aliphatic polyglycidyl ether.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aliphatic polyglycidyl ether. 721.3520... Substances § 721.3520 Aliphatic polyglycidyl ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aliphatic polyglycidyl ether (PMN P-89-1036) is subject...

  13. 40 CFR 721.3520 - Aliphatic polyglycidyl ether.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aliphatic polyglycidyl ether. 721.3520... Substances § 721.3520 Aliphatic polyglycidyl ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aliphatic polyglycidyl ether (PMN P-89-1036) is subject...

  14. Enzymatic degradation of aliphatic nitriles by Rhodococcus rhodochrous BX2, a versatile nitrile-degrading bacterium.

    PubMed

    Fang, Shumei; An, Xuejiao; Liu, Hongyuan; Cheng, Yi; Hou, Ning; Feng, Lu; Huang, Xinning; Li, Chunyan

    2015-06-01

    Nitriles are common environmental pollutants, and their removal has attracted increasing attention. Microbial degradation is considered to be the most acceptable method for removal. In this work, we investigated the biodegradation of three aliphatic nitriles (acetonitrile, acrylonitrile and crotononitrile) by Rhodococcus rhodochrous BX2 and the expression of their corresponding metabolic enzymes. This organism can utilize all three aliphatic nitriles as sole carbon and nitrogen sources, resulting in the complete degradation of these compounds. The degradation kinetics were described using a first-order model. The degradation efficiency was ranked according to t1/2 as follows: acetonitrile>trans-crotononitrile>acrylonitrile>cis-crotononitrile. Only ammonia accumulated following the three nitriles degradation, while amides and carboxylic acids were transient and disappeared by the end of the assay. mRNA expression and enzyme activity indicated that the tested aliphatic nitriles were degraded via both the inducible NHase/amidase and the constitutive nitrilase pathways, with the former most likely preferred.

  15. Aliphatic long-chain C20 polyesters from olefin metathesis.

    PubMed

    Trzaskowski, Justyna; Quinzler, Dorothee; Bährle, Christian; Mecking, Stefan

    2011-09-01

    Self-metathesis of undecenoic acid with [(PCy3)2Cl2Ru=CHPh] (2), followed by exhaustive hydrogenation yielded pure 1,20-eicosanedioic acid (5) (>99%) free of side-products from isomerization. Polycondensation with eicosane-1,20-diol (6), formed by reduction of the diol, yielded polyester 20,20 (Tm = 108 °C). By comparison, the known ADMET polymerization of undec-10-enyl undec-10-enoate (7), and subsequent exhaustive polymer-analogous hydrogenation yielded a polyester (poly-8) with irregular structure of the ester groups in the polymer chain (-O(C=O)- vs. -C(=O)O-) (Tm = 103 °C). Hydrogenation of secondary dispersions of poly-7 yielded aqueous dispersions of the long-chain aliphatic polyester poly-8.

  16. Renaissance of Aliphatic Polycarbonates: New Techniques and Biomedical Applications

    PubMed Central

    Xu, Jianwen; Feng, Ellva; Song, Jie

    2014-01-01

    Aliphatic polycarbonates were discovered a long time ago, with their conventional applications mostly limited to low molecular weight oligomeric intermediates for copolymerization with other polymers. Recent developments in polymerization techniques have overcome the difficulty in preparing high molecular weight aliphatic polycarbonates. These in turn, along with new functional monomers, have enabled the preparation of a wide range of aliphatic polycarbonates with diverse chemical compositions and structures. This review summarizes the latest polymerization techniques for preparing well-defined functional aliphatic polycarbonates, as well as the new applications of those aliphatic polycarbonates, esecially in the biomedical field. PMID:24994939

  17. A combined experimental and DFT/TDDFT investigation of structural, electronic, and pH-induced tuning of photophysical and redox properties of osmium(II) mixed-chelates derived from imidazole-4,5-dicarboxylic acid and 2,2'-bipyridine.

    PubMed

    Das, Shyamal; Saha, Debasish; Mardanya, Sourav; Baitalik, Sujoy

    2012-10-21

    Experimental results coupled with computational studies were utilized to investigate the structural and electronic properties of mixed-ligand monometallic osmium(II) complexes of composition [(bipy)(2)Os(H(2)Imdc)](+) (1(+)), the N-H deprotonated form [(bipy)(2)Os(HImdc)] (1), and the COOH deprotonated form [(bipy)(2)Os(Imdc)](-) (1(-)), where H(3)Imdc = imidazole-4,5-dicarboxylic acid and bipy = 2,2'-bipyridine. The X-ray crystal structures of [(bipy)(2)Os(H(2)Imdc)](+) (1(+)) and [(bipy)(2)Os(HImdc)] (1) have been determined, which showed that compound 1(+) crystallizes in a monoclinic form with the space group P2(1)/c, while 1 is obtained in a triclinic form with the space group P1[combining macron]. The optimized geometrical parameters for the complexes computed both in the gas phase and in solution are reported and compared with the available X-ray data. The influence of pH on the photophysical and redox properties of the complexes has been thoroughly investigated. As compared to protonated complex (1(+)), which undergoes reversible oxidation at 0.50 V (vs. Ag/AgCl) in acetonitrile, the redox potential of the fully deprotonated complex (1(-)) is shifted to a much lower value, 0.16 V. The proton-coupled redox activity of 1(+) has been studied over the pH range 2-12 in an acetonitrile-water (3 : 2) medium. From the pH versus E(1/2) profile, the equilibrium constants of the complex species in the protonated/deprotonated forms and the metal ion in +2/+3 oxidation states have been determined. Using these values the bond dissociation free energies for the imidazole N-H and COOH bonds have also been estimated. The pK(a) values for 1(+) in the +2 state have also been determined spectrophotometrically. Substantial red shifts in the MLCT bands and the large shift in the E(1/2) value to a less positive potential that occur on deprotonation are energetically correlated. Density functional theory (DFT) and time-dependent DFT (TD-DFT) studies provide insight into the nature

  18. Combinations of Aromatic and Aliphatic Radiolysis.

    PubMed

    LaVerne, Jay A; Dowling-Medley, Jennifer

    2015-10-01

    The production of H(2) in the radiolysis of benzene, methylbenzene (toluene), ethylbenzene, butylbenzene, and hexylbenzene with γ-rays, 2-10 MeV protons, 5-20 MeV helium ions, and 10-30 MeV carbon ions is used as a probe of the overall radiation sensitivity and to determine the relative contributions of aromatic and aliphatic entities in mixed hydrocarbons. The addition of an aliphatic side chain with progressively from one to six carbon lengths to benzene increases the H(2) yield with γ-rays, but the yield seems to reach a plateau far below that found from a simple aliphatic such as cyclohexane. There is a large increase in H(2) with LET (linear energy transfer) for all of the substituted benzenes, which indicates that the main process for H(2) formation is a second-order process and dominated by the aromatic entity. The addition of a small amount of benzene to cyclohexane can lower the H(2) yield from the value expected from a simple mixture law. A 50:50% volume mixture of benzene-cyclohexane has essentially the same H(2) yield as cyclohexylbenzene at a wide variation in LET, suggesting that intermolecular energy transfer is as efficient as intramolecular energy transfer.

  19. Spider monkeys (Ateles geoffroyi) are less sensitive to the odor of aliphatic ketones than to the odor of other classes of aliphatic compounds.

    PubMed

    Eliasson, Moa; Hernandez Salazar, Laura Teresa; Laska, Matthias

    2015-10-01

    Aliphatic ketones are widely present in body-borne and food odors of primates. Therefore, we used an operant conditioning paradigm and determined olfactory detection thresholds in four spider monkeys for a homologous series of aliphatic 2-ketones (2-butanone to 2-nonanone) and two of their isomers (3- and 4-heptanone). We found that, with the exception of the two shortest-chained ketones, all animals detected concentrations <1 ppm (parts per million), and with five odorants individual animals even reached threshold values <0.1 ppm. Further, we found a significant correlation between olfactory sensitivity of the spider monkeys and carbon chain length of the 2-ketones which can best be described as a U-shaped function. In contrast, no significant correlation was found between olfactory sensitivity and position of the functional carbonyl group. Across-odorant and across-species comparisons revealed the following: spider monkeys are significantly less sensitive to the odors of aliphatic ketones than to the odor of other classes of aliphatic compounds (1-alcohols, n-aldehydes, n-acetic esters, and n-carboxylic acids) sharing the same carbon length. Spider monkeys do not differ significantly in their olfactory sensitivity for aliphatic ketones from squirrel monkeys and pigtail macaques, but are significantly less sensitive to these odorants compared to human subjects and mice. These findings support the notion that neuroanatomical and genetic properties do not allow for reliable predictions with regard to a species' olfactory sensitivity. Further, we conclude that the frequency of occurrence of a class of odorants in a species' chemical environment does not allow for reliable predictions of the species' olfactory sensitivity. PMID:26055441

  20. Studies of the acidic components of the Colorado Green River formation oil shale-Mass spectrometric identification of the methyl esters of extractable acids.

    NASA Technical Reports Server (NTRS)

    Haug, P.; Schnoes, H. K.; Burlingame, A. L.

    1971-01-01

    Study of solvent extractable acidic constituents of oil shale from the Colorado Green River Formation. Identification of individual components is based on gas chromatographic and mass spectrometric data obtained for their respective methyl esters. Normal acids, isoprenoidal acids, alpha, omega-dicarboxylic acids, mono-alpha-methyl dicarboxylic acids and methyl ketoacids were identified. In addition, the presence of monocyclic, benzoic, phenylalkanoic and naphthyl-carboxylic acids, as well as cycloaromatic acids, is demonstrated by partial identification.

  1. 40 CFR 721.3000 - Dicarboxylic acid monoester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... point type, the following statements: WARNING! HARMFUL IF INHALED OR ABSORBED THROUGH THE SKIN. MAY CAUSE REPRODUCTIVE EFFECTS. —Do not get in eye, on skin, or clothing. —Do not breathe (vapor, mist... least 15 minutes. SKIN: Promptly wash thoroughly with mild soap and water. INHALATION: Remove to...

  2. 40 CFR 721.3000 - Dicarboxylic acid monoester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CAUSE REPRODUCTIVE EFFECTS. —Do not get in eye, on skin, or clothing. —Do not breathe (vapor, mist... smoking. —Keep container closed. FIRST AID: In case of contact. EYES: Immediately flush with water for...

  3. 40 CFR 721.3000 - Dicarboxylic acid monoester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CAUSE REPRODUCTIVE EFFECTS. —Do not get in eye, on skin, or clothing. —Do not breathe (vapor, mist... smoking. —Keep container closed. FIRST AID: In case of contact. EYES: Immediately flush with water for...

  4. Mass spectrometry study of the sublimation of aliphatic dipeptides

    NASA Astrophysics Data System (ADS)

    Badelin, V. G.; Tyunina, E. Yu.; Krasnov, A. V.; Tyunina, V. V.; Giricheva, N. I.; Girichev, A. V.

    2012-03-01

    The sublimation of glycyl-L-α-alanine (Gly-Ala), L-α-alanyl-L-α-alanine (Ala-Ala), and DL-α-alanyl-DL-α-valine (Ala-Val) aliphatic dipeptides is studied by electron ionization mass spectrometry in combination with Knudsen effusion. The temperature range in which substances sublime as monomer molecular forms is determined. Enthalpies of sublimation Δs H°( T) are determined for Gly-Ala, Ala-Ala, and Ala-Val. It is shown that the enthalpy of sublimation of dipeptides increases with an increase in the side hydrocarbon radical. The unknown Δs H°(298) values for 17 amino acids and nine dipeptides are estimated using the proposed "structure-property" correlation model, in which the geometry and electron characteristics of molecules are used as structural descriptors.

  5. CYP79F1 and CYP79F2 have distinct functions in the biosynthesis of aliphatic glucosinolates in Arabidopsis.

    PubMed

    Chen, Sixue; Glawischnig, Erich; Jørgensen, Kirsten; Naur, Peter; Jørgensen, Bodil; Olsen, Carl-Erik; Hansen, Carsten H; Rasmussen, Hasse; Pickett, John A; Halkier, Barbara A

    2003-03-01

    Cytochromes P450 of the CYP79 family catalyze the conversion of amino acids to oximes in the biosynthesis of glucosinolates, a group of natural plant products known to be involved in plant defense and as a source of flavor compounds, cancer-preventing agents and bioherbicides. We report a detailed biochemical analysis of the substrate specificity and kinetics of CYP79F1 and CYP79F2, two cytochromes P450 involved in the biosynthesis of aliphatic glucosinolates in Arabidopsis thaliana. Using recombinant CYP79F1 and CYP79F2 expressed in Escherichia coli and Saccharomyces cerevisiae, respectively, we show that CYP79F1 metabolizes mono- to hexahomomethionine, resulting in both short- and long-chain aliphatic glucosinolates. In contrast, CYP79F2 exclusively metabolizes long-chain elongated penta- and hexahomomethionines. CYP79F1 and CYP79F2 are spatially and developmentally regulated, with different gene expression patterns. CYP79F2 is highly expressed in hypocotyl and roots, whereas CYP79F1 is strongly expressed in cotyledons, rosette leaves, stems, and siliques. A transposon-tagged CYP79F1 knockout mutant completely lacks short-chain aliphatic glucosinolates, but has an increased level of long-chain aliphatic glucosinolates, especially in leaves and seeds. The level of long-chain aliphatic glucosinolates in a transposon-tagged CYP79F2 knockout mutant is substantially reduced, whereas the level of short-chain aliphatic glucosinolates is not affected. Biochemical characterization of CYP79F1 and CYP79F2, and gene expression analysis, combined with glucosinolate profiling of knockout mutants demonstrate the functional role of these enzymes. This provides valuable insights into the metabolic network leading to the biosynthesis of aliphatic glucosinolates, and into metabolic engineering of altered aliphatic glucosinolate profiles to improve nutritional value and pest resistance. PMID:12609033

  6. Novel synthetic method for the preparation of amphiphilic hyaluronan by means of aliphatic aromatic anhydrides.

    PubMed

    Huerta-Angeles, Gloria; Bobek, Martin; Příkopová, Eva; Šmejkalová, Daniela; Velebný, Vladimír

    2014-10-13

    The present work describes a novel and efficient method of synthesis of amphiphilic hyaluronan (HA) by esterification with alkyl fatty acids. These derivatives were synthesized under mild aqueous and well controlled conditions using mixed aliphatic aromatic anhydrides. These anhydrides characterized by the general formula RCOOCOC6H2Cl3 can be easily prepared by the reaction of the corresponding fatty acid (R) with 2,4,6-trichlorobenzoyl chloride (TCBC) in the presence of triethylamine. The aliphatic aromatic anhydrides RCOOCOC6H2Cl3 then react with the polysaccharide and enable the synthesis of aliphatic acid esters of HA in good yields. No hydrolytic degradation of hyaluronic acid could be observed. Parameters controlling the degree of esterification were systematically studied. Fatty acids with different chain lengths can be introduced applying this methodology. The degree of substitution was decreasing with increasing length of hydrophobic chain. The reaction products were fully characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), SEC-MALLS and chromatographic analyses. Although the esterified HA products exhibited aggregation in solution as demonstrated by NMR, microscopy and rheology, they were still water-soluble.

  7. Interior and Interfacial Aqueous Solvation of Benzene Dicarboxylate Dianions and Their Methylated Analogues: A Combined Molecular Dynamics and Photoelectron Spectroscopy Study

    SciTech Connect

    Minofar, Babak; Vrbka, Lubos; Mucha, Martin; Jungwirth, Pavel; Yang, Xin; Wang, Xue B.; Fu, Youjun; Wang, Lai S.

    2005-06-16

    Aqueous solvation of benzene dicarboxylate dianions (BCD2-) was studied by means of photoelectron spectroscopy and molecular dynamics simulations. Photoelectron spectra of hydrated ortho-, and para-BCD2- with up to 25 water molecules were obtained. An even-odd effect was observed for the p-BCD2- system as a result of the alternate solvation of the two negative charges. However, the high polarizability of the benzene ring makes the two carboxylate groups interact with each other in p-BCD2-, suppressing the strength of this even-odd effect compared with the linear dicarboxylate dianions linked by an aliphatic chain. No even-odd effect was observed for the o-BCD2- system, because each solvent molecule can interact with the two carboxylate groups at the same time due to their proximity. For large solvated clusters, the spectral features of the solute decreased while the solvent features became dominant, suggesting that both o- and p-BCD2- are situated in the center of the solvated clusters. Molecular dynamics simulations with both non-polarizable and polarizable force fields confirmed that all three isomers (o-, m-, and p-BCD2-) solvate in the aqueous bulk. However, upon methylation the hydrophobic forces overwhelm electrostatic interactions and, as a result, the calculations predict that the tetra-methyl o-BCD2- is located at the water surface with the carboxylate groups anchored in the liquid and the methylated benzene ring tilted away from the aqueous phase.

  8. Spreading coefficients of aliphatic hydrocarbons on water

    SciTech Connect

    Takii, Taichi; Mori, Y.H. . Dept. of Mechanical Engineering)

    1993-11-01

    Experiments have been performed to determine the equilibrium spreading coefficients of some aliphatic hydrocarbons (C[sub 6]C[sub 10]) on water. The thickness of a discrete lens of each hydrocarbon sample floating on a stagnant water pool was measured interferometrically and used to calculate the spreading coefficient of the hydrocarbon with the aid of Langmuir's capillarity theory. The dependences of the spreading coefficient, thus observed, on temperature (0--50 C) and on the number of carbon atoms in the hydrocarbon molecule are in qualitative agreement with the predictions based on the Lifshitz theory of van der Waals forces.

  9. Biofiltration of gasoline and diesel aliphatic hydrocarbons.

    PubMed

    Halecky, Martin; Rousova, Jana; Paca, Jan; Kozliak, Evguenii; Seames, Wayne; Jones, Kim

    2015-02-01

    The ability of a biofilm to switch between the mixtures of mostly aromatic and aliphatic hydrocarbons was investigated to assess biofiltration efficiency and potential substrate interactions. A switch from gasoline, which consisted of both aliphatic and aromatic hydrocarbons, to a mixture of volatile diesel n-alkanes resulted in a significant increase in biofiltration efficiency, despite the lack of readily biodegradable aromatic hydrocarbons in the diesel mixture. This improved biofilter performance was shown to be the result of the presence of larger size (C₉-C(12)) linear alkanes in diesel, which turned out to be more degradable than their shorter-chain (C₆-C₈) homologues in gasoline. The evidence obtained from both biofiltration-based and independent microbiological tests indicated that the rate was limited by biochemical reactions, with the inhibition of shorter chain alkane biodegradation by their larger size homologues as corroborated by a significant substrate specialization along the biofilter bed. These observations were explained by the lack of specific enzymes designed for the oxidation of short-chain alkanes as opposed to their longer carbon chain homologues.

  10. Gaseous aliphatic aldehydes in Chinese incense smoke

    SciTech Connect

    Lin, J.M.; Wang, L.H. )

    1994-09-01

    Aliphatic aldehydes were found during the combustion of materials. Tobacco smoke contains aldehydes. Fire fighters were exposed to aldehydes when they conducted firefighting. Aldehydes in ambient air come mainly from the incomplete combustion of hydrocarbons and from photochemical reaction. Most aldehydes in ambient air are formaldehyde and acetaldehyde. Formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and benzaldehyde were found in the atmosphere in Los Angeles. Burning Chinese incense for worshipping deities is a Chinese daily routine. It was suspected to be a factor causing nasopharynegeal cancer. Epidemiological studies correlated it with the high risk of childhood brain tumor and the high risk of childhood leukemia. Ames test identified the mutagenic effect of the smoke from burning Chinese incense. The smoke had bee proved to contain polycyclic aromatic hydrocarbons and aromatic aldehydes. Suspicion about formaldehyde and other alphatic aldehydes was evoked, when a survey of indoor air pollution was conducted in Taipei city. This study determined the presence of aliphatic aldehydes in the smoke from burning Chinese incense under a controlled atmosphere. 12 refs., 5 figs., 2 tabs.

  11. Biodegradation of aliphatic and aromatic polycarbonates.

    PubMed

    Artham, Trishul; Doble, Mukesh

    2008-01-01

    Polycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to biodegrade either through the action of pure enzymes or by bacterial whole cells. Very little information is available that deals with the biodegradation of aromatic polycarbonates. Biodegradation is governed by different factors that include polymer characteristics, type of organism, and nature of pretreatment. The polymer characteristics such as its mobility, tacticity, crystallinity, molecular weight, the type of functional groups and substituents present in its structure, and plasticizers or additives added to the polymer all play an important role in its degradation. The carbonate bond in aliphatic polycarbonates is facile and hence this polymer is easily biodegradable. On the other hand, bisphenol A polycarbonate contains benzene rings and quaternary carbon atoms which form bulky and stiff chains that enhance rigidity. Even though this polycarbonate is amorphous in nature because of considerable free volume, it is non-biodegradable since the carbonate bond is inaccessible to enzymes because of the presence of bulky phenyl groups on either side. In order to facilitate the biodegradation of polymers few pretreatment techniques which include photo-oxidation, gamma-irradiation, or use of chemicals have been tested. Addition of biosurfactants to improve the interaction between the polymer and the microorganisms, and blending with natural or synthetic polymers that degrade easily, can also enhance the biodegradation.

  12. Mn2(2,5-disulfhydrylbenzene-1,4-dicarboxylate): a microporous metal-organic framework with infinite (-Mn-S-)∞ chains and high intrinsic charge mobility.

    PubMed

    Sun, Lei; Miyakai, Tomoyo; Seki, Shu; Dincă, Mircea

    2013-06-01

    The reaction of MnCl2 with 2,5-disulfhydrylbenzene-1,4-dicarboxylic acid (H4DSBDC), in which the phenol groups in 2,5-dihydroxybenzene-1,4-dicarboxylic acid (H4DOBDC) have been replaced by thiophenol units, led to the isolation of Mn2(DSBDC), a thiolated analogue of the M2(DOBDC) series of metal-organic frameworks (MOFs). The sulfur atoms participate in infinite one-dimensional Mn-S chains, and Mn2(DSBDC) shows a high surface area and high charge mobility similar to that found in some of the most common organic semiconductors. The synthetic approach to Mn2(DSBDC) and its excellent electronic properties provide a blueprint for a potentially rich area of exploration in microporous conductive MOFs with low-dimensional charge transport pathways.

  13. Sodium hypochlorite oxidation of petroleum aliphatic contaminants in calcareous soils.

    PubMed

    Picard, François; Chaouki, Jamal

    2016-02-01

    This research project investigated the sodium hypochlorite (NaClO) oxidation of aliphatic petroleum contaminants (C10-C50) in a calcareous soil (average 5473 ppm C10-C50, 15 wt% Ca), which had been excavated from a contaminated industrial site. The decontamination objective was to lower the C10-C50 concentration to 700 ppm. CO2 acidity was used in the project to boost the NaClO oxidation yield and seems to have played a role in desorbing the natural organic matter. The experimental conditions were a 2- to 16-h reaction time, at room temperature, with a 1 to 12.5 wt% NaClO oxidative solution and a fixed 2:1 solution-to-soil ratio. With a 3 wt% NaClO solution and with a CO2 overhead, the NaClO dosage requirement was maintained below 60 g NaClO/g of oxidized C10-C50 over the entire decontamination range. The strong chlorine smell remaining after the reaction was completed suggests that part of the NaClO requirement can be recycled. Except traces of chloroform, there were no regulation-listed organochloride contaminants detected on either the treated soil samples or leachates and the total count of chlorinated compounds in treated soil samples was below the detection limit of 250 mg/kg. The NaClO oxidation mechanism on aliphatic substrates might be triggered by transition metals, such as manganese, but no attempt has been made to investigate the oxidation mechanism. Further investigations would include a constant-fed NaClO system and other techniques to lower the required NaClO dosage.

  14. 40 CFR 721.4497 - Aliphatic polyisocyanates (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aliphatic polyisocyanates (generic name). 721.4497 Section 721.4497 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.4497 Aliphatic polyisocyanates (generic name). (a) Chemical...

  15. Metalloradical-catalyzed aliphatic carbon-carbon activation of cyclooctane.

    PubMed

    Chan, Yun Wai; Chan, Kin Shing

    2010-05-26

    The aliphatic carbon-carbon activation of c-octane was achieved via the addition of Rh(ttp)H to give Rh(ttp)(n-octyl) in good yield under mild reaction conditions. The aliphatic carbon-carbon activation was Rh(II)(ttp)-catalyzed and was very sensitive to porphyrin sterics.

  16. Aryl isomerization during aliphatic CH bond activation

    SciTech Connect

    Chamberlain, L.R.; Rothwell, I.P.

    1983-03-23

    The transition-metal-stablized benzyne or o-phenylene (n/sup 2/-C/sub 6/H/sub 4/) ligand has been shown to be both an interesting and reactive group. The ligand is normally generated in mononuclear systems by ..beta..- (ortho-) hydrogen abstraction from an aryl group, and this synthetic approach has allowed a stable example to be isolated and structurally characterized. Here the conclusive identification of a benzyne intermediate during the isomerization of a tantalum-aryl compound is reported. The reaction is interesting in that the ortho hydrogen is transferred to the carbon atom of a cyclometalated chelate, the reverse (isomerization) step thus involving the activation of an aliphatic CH bond by the intermediate benzyne.

  17. Validation of Alternatives to Aliphatic Isocyanate Polyurethanes

    NASA Technical Reports Server (NTRS)

    Curran, Jerome

    2007-01-01

    The National Aeronautics and Space Administration (NASA) Headquarters chartered the Acquisition Pollution Prevention (AP2) Office to coordinate agency activities affecting pollution prevention issues identified during system and component acquisition and sustainment processes. The primary objective of this effort is to demonstrate and validate alternatives to aliphatic isocyanate polyurethane coatings. Successful completion of this project will result in one or more isocyanate-free coating systems qualified for use at Air Force Space Command (AFSPC) and NASA centers participating in this study. The objective of this project is to qualify the candidates under the specifications for the standard system. This project will compare coating performance of the proposed alternatives to existing coating systems or standards.

  18. Stable isotope investigations of chlorinated aliphatic hydrocarbons.

    SciTech Connect

    Abrajano, T.; Heraty, L. J.; Holt, B. D.; Huang, L.; Sturchio, N. C.

    1999-06-01

    Stable isotope ratio measurements for carbon (C) and chlorine (Cl) can be used to elucidate the processes affecting transformation and transportation of chlorinated aliphatic hydrocarbons (CAHs) in the environment. Methods recently developed in our laboratory for isotopic analysis of CAHs have been applied to laboratory measurements of the kinetic isotope effects associated with aerobic degradation of dichloromethane (DCM) and with both anaerobic and aerobic cometabolic degradation of trichlomethene (TCE) in batch and column microbial cultures. These experimental determinations of fractionation factors are crucial for understanding the behavior of CAHs in complex natural systems, where the extent of biotransformation can be masked by dispersion and volatilization. We have also performed laboratory investigations of kinetic isotope effects accompanying evaporation of CAHs, as well as field investigations of natural attenuation and in situ remediation of CAHs in a number of contaminated shallow aquifers at sites operated by the federal government and the private sector.

  19. NO3 and OH initiated secondary aerosol formation from aliphatic amines - salt formation and effect of water vapor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aliphatic amines enter the atmosphere from a variety of sources, and have been detected existing in gas and particle phases in the atmosphere. Similar to ammonia, amines can form inorganic salt through acid-base reactions. However, the atmospheric behavior of amines with atmospheric oxidants (e.g. n...

  20. NO3 radical, OH radical and O3-initiated secondary aerosol formation from aliphatic amines

    NASA Astrophysics Data System (ADS)

    Tang, Xiaochen; Price, Derek; Praske, Eric; Lee, Su Anne; Shattuck, Morgan A.; Purvis-Roberts, Kathleen; Silva, Philip J.; Asa-Awuku, Akua; Cocker, David R.

    2013-06-01

    Aliphatic amines enter the atmosphere from a variety of sources, and exist in both gas and particle phases in the atmosphere. Similar to ammonia, amines can form inorganic salts through acid-base reactions. However, the atmospheric behavior of amines with atmospheric oxidants (e.g. the nitrate radical (NO3), the hydroxyl radical (OH), O3) is still poorly understood. In this study, chamber experiments were conducted to explore the reaction between three aliphatic amines and HNO3/O3/NO3/OH. Effects of water vapor were also explored by conducting experiments under different relative humidity conditions (RH<0.1% to ˜40%). Results show that all three amines have a high potential to form secondary aerosol in reactions with NO3, and are affected by the presence of water vapor. DEA and BA are capable of forming a significant amount of stable inorganic salt at ppb level concentrations, while TMA tends to form mostly non-salt secondary organic aerosol under dry conditions. The OH photooxidation of amines has much lower secondary aerosol yield and is independent of relative humidity, while ozonolysis produced negligible amount of aerosol. Secondary aerosol from OH oxidation was composed of organic components only, due to the lack of acid source. This study shows that night time chemistry of aliphatic amines can produce secondary organic and inorganic aerosol mixtures, and the relative contribution of each component depends on the environment relative humidity.

  1. Solvothermal synthesis and structure of 3D frameworks of Nd(III) and Y(III) with thiophene-2,5-dicarboxylate and N,N‧-diethylformamide

    NASA Astrophysics Data System (ADS)

    Sharma, Swati; Yawer, Mohd; Kariem, Mukaddus; Sheikh, Haq Nawaz

    2016-08-01

    Two new 3D MOFs [Nd2(TDA)3(DEF)2(H2O)]n (1) and [Y4(TDA)6(DEF)4]n (2) [Thiophene-2,5-dicarboxylic acid (H2TDA) and N,N‧-diethylformamide (DEF)] were synthesized by solvothermal method. They were characterized by elemental analyses, infrared spectroscopy and single crystal X-ray diffraction studies. The two MOFs (1) and (2) belong to the monoclinic system with space group P21/n and C 2 respectively. Structural characterizations by single-crystal X-ray crystallography reveal that 1 and 2 adopt three-dimensional frameworks constructed by cross-linking of rod shaped infinite chain secondary building unit (SBU) by thiophene-2,5-dicarboxylates as linker. These frameworks feature rhomboidal channels, inside which coordinated DEF/H2O solvent molecules are located. DEF plays pivotal role in reaction and design of MOFs. Thermogravimetric analysis shows that both MOFs are thermally robust.

  2. Adsorption of halogenated aliphatic contaminants by graphene nanomaterials.

    PubMed

    Zhou, Yang; Apul, Onur Guven; Karanfil, Tanju

    2015-08-01

    In this study, adsorption of ten environmentally halogenated aliphatic synthetic organic compounds (SOCs) by a pristine graphene nanosheet (GNS) and a reduced graphene oxide (rGO) was examined, and their adsorption behaviors were compared with those of a single-walled carbon nanotube (SWCNT) and a granular activated carbon (GAC). In addition, the impacts of background water components (i.e., natural organic matter (NOM), ionic strength (IS) and pH) on the SOC adsorption behavior were investigated. The results indicated HD3000 and SWCNT with higher microporous volumes exhibited higher adsorption capacities for the selected aliphatic SOCs than graphenes, demonstrating microporosity of carbonaceous adsorbents played an important role in the adsorption. Analysis of adsorption isotherms demonstrated that hydrophobic interactions were the dominant contributor to the adsorption of aliphatic SOCs by graphenes. However, π-π electron donor-acceptor and van der Waals interactions are likely the additional mechanisms contributing to the adsorption of aliphatic SOCs on graphenes. Among the three background solution components examined, NOM showed the most influential effect on adsorption of the selected aliphatic SOCs, while pH and ionic strength had a negligible effects. The NOM competition on aliphatic adsorption was less pronounced on graphenes than SWCNT. Overall, in terms of adsorption capacities, graphenes tested in this study did not exhibit a major advantage over SWCNT and GAC for the adsorption of aliphatic SOCs.

  3. Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes

    PubMed Central

    Vida, Norbert; Václavík, Jiří

    2016-01-01

    Summary Oxidation of 3- and 4-pentafluorosulfanyl-substituted anisoles and phenols with hydrogen peroxide and sulfuric acid provided a mixture of SF5-substituted muconolactone, maleic, and succinic acids. A plausible mechanism for the formation of the aliphatic SF5 compounds was presented and their chemical reactivity was investigated. SF5-substituted para-benzoquinone was synthesized; its oxidation led to an improved yield of 2-(pentafluorosulfanyl)maleic acid. The reaction of SF5-substituted maleic anhydride and para-benzoquinone with cyclopentadiene afforded the Diels–Alder adducts. Decomposition of 3-(pentafluorosulfanyl)muconolactone in acidic, neutral and basic aqueous media was investigated and the decarboxylation of 2-(pentafluorosulfanyl)maleic acid provided 3-(pentafluorosulfanyl)acrylic acid. PMID:26877813

  4. Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes.

    PubMed

    Vida, Norbert; Václavík, Jiří; Beier, Petr

    2016-01-01

    Oxidation of 3- and 4-pentafluorosulfanyl-substituted anisoles and phenols with hydrogen peroxide and sulfuric acid provided a mixture of SF5-substituted muconolactone, maleic, and succinic acids. A plausible mechanism for the formation of the aliphatic SF5 compounds was presented and their chemical reactivity was investigated. SF5-substituted para-benzoquinone was synthesized; its oxidation led to an improved yield of 2-(pentafluorosulfanyl)maleic acid. The reaction of SF5-substituted maleic anhydride and para-benzoquinone with cyclopentadiene afforded the Diels-Alder adducts. Decomposition of 3-(pentafluorosulfanyl)muconolactone in acidic, neutral and basic aqueous media was investigated and the decarboxylation of 2-(pentafluorosulfanyl)maleic acid provided 3-(pentafluorosulfanyl)acrylic acid. PMID:26877813

  5. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    EPA Science Inventory

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  6. Phenylethanoid and aliphatic alcohol glycosides from Acanthus ilicifolius.

    PubMed

    Wu, Jun; Zhang, Si; Xiao, Qiang; Li, Qingxin; Huang, Jianshe; Long, Lijuan; Huang, Liangmin

    2003-06-01

    A phenylethanoid glycoside (ilicifolioside A) and an aliphatic alcohol glycoside (ilicifolioside B), have been isolated from the aerial parts of Acanthus ilicifolius, together with eight known compounds. Their structures were determined from spectroscopic analyses.

  7. Evaluation of antibacterial activity of synthetic aliphatic and aromatic monoacylglycerols.

    PubMed

    Batovska, Daniela; Todorova, Iva; Parushev, Stoyan; Tsvetkova, Iva; Najdenski, Hristo; Ubukata, Makoto

    2008-01-01

    The antibacterial activity of synthetic aliphatic and aromatic monoacylglycerols (MAGs) was studied against two human pathogens: Staphylococcus aureus and Escherichia coli. The active compounds inhibited selectively S. aureus. The most active compounds amongst them were those with medium size aliphatic chain and aromatic MAGs with electron withdrawing substituents at the aryl ring. The introduction of one or two-carbon spacer between the aryl ring and the carboxylic function did not influence antibacterial effectiveness. PMID:19004249

  8. Olfactory discrimination ability for aliphatic esters in squirrel monkeys and humans.

    PubMed

    Laska, M; Freyer, D

    1997-08-01

    Using a behavioral paradigm designed to simulate olfactory-guided foraging, the ability of five squirrel monkeys to distinguish iso-amyl acetate from n- and iso-forms of other acetic esters (ethyl acetate to decyl acetate) and from other esters carrying the iso-amyl group (iso-amyl propionate to iso-amyl capronate) was investigated. We found (i) that all five animals were clearly able to discriminate between all odor pairs tested; (ii) a significant negative correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length of both the aliphatic alcohol group and the aliphatic acid group of the esters; and (iii) that iso- and n-amyl acetate were perceived as qualitatively similar despite different steric conformation. Using a triple-forced choice procedure, 20 human subjects were tested on the same tasks in parallel and showed a very similar pattern of discrimination performance compared with the squirrel monkeys. Thus, the results of this study provide evidence of well-developed olfactory discrimination ability in squirrel monkeys for aliphatic esters and support the assumption that human and non-human primates may share common principles of odor quality perception. PMID:9279468

  9. Dimethyl dimethoxy biphenyl dicarboxylate attenuates hepatic and metabolic alterations in high fructose-fed rats.

    PubMed

    Morsy, Mohamed A; Ibrahim, Mohamed A; Abd-Elghany, Manal I

    2016-01-01

    High fructose consumption is currently linked to metabolic disorders including insulin resistance and dyslipidemia as well as hepatic steatosis. Dimethyl dimethoxy biphenyl dicarboxylate (DDB) is a hepatoprotectant with antioxidant and anti-inflammatory properties. The aim of this study therefore is to evaluate the effect of DDB on high fructose-induced metabolic disturbances and hepatic steatosis in a rat model. Male Wistar rats were allocated into three groups: control, fructose-fed (10% in drinking water and 10% in diet), and fructose-fed DDB (300 mg/kg, orally)-treated groups. Rats were fed a high-fructose diet for 6 weeks, while DDB was administered for an additional 2 weeks. High-fructose consumption elevated serum glucose and insulin levels and impaired oral glucose tolerance test, revealing insulin resistance. It also increased serum triglycerides and alanine aminotransferase as well as visceral fat content and decreased serum high-density lipoprotein. Additionally, histopathological examination revealed that high fructose intake induced hepatic steatosis. These alterations were associated with increased serum uric acid as well as hepatic content of malondialdehyde and nitric oxide (NO) in addition to overexpression of inducible NO synthase (iNOS). DDB administration significantly ameliorated the high fructose-induced hepatic and metabolic alterations. In conclusion, DDB ameliorates high fructose-induced metabolic disorders and hepatic steatosis in rats. Such protection is, at least in part, due to the inhibition of lipid peroxidation, decrease in iNOS overexpression, and reduction of elevated uric acid.

  10. Topsoil drying combined with increased sulfur supply leads to enhanced aliphatic glucosinolates in Brassica juncea leaves and roots.

    PubMed

    Tong, Yu; Gabriel-Neumann, Elke; Ngwene, Benard; Krumbein, Angelika; George, Eckhard; Platz, Stefanie; Rohn, Sascha; Schreiner, Monika

    2014-01-01

    The decrease of water availability is leading to an urgent demand to reduce the plants' water supply. This study evaluates the effect of topsoil drying, combined with varying sulfur (S) supply on glucosinolates in Brassica juncea in order to reveal whether a partial root drying may already lead to a drought-induced glucosinolate increase promoted by an enhanced S supply. Without decreasing biomass, topsoil drying initiated an increase in aliphatic glucosinolates in leaves and in topsoil dried roots supported by increased S supply. Simultaneously, abscisic acid was determined, particularly in dehydrated roots, associated with an increased abscisic acid concentration in leaves under topsoil drying. This indicates that the dehydrated roots were the direct interface for the plants' stress response and that the drought-induced accumulation of aliphatic glucosinolates is related to abscisic acid formation. Indole and aromatic glucosinolates decreased, suggesting that these glucosinolates are less involved in the plants' response to drought. PMID:24444925

  11. Aliphatic chain length by isotropic mixing (ALCHIM): determining composition of complex lipid samples by 1H NMR spectroscopy

    PubMed Central

    Yi, Ruiyang; Volden, Paul A.; Conzen, Suzanne D.

    2015-01-01

    Quantifying the amounts and types of lipids present in mixtures is important in fields as diverse as medicine, food science, and biochemistry. Nuclear magnetic resonance (NMR) spectroscopy can quantify the total amounts of saturated and unsaturated fatty acids in mixtures, but identifying the length of saturated fatty acid or the position of unsaturation by NMR is a daunting challenge. We have developed an NMR technique, aliphatic chain length by isotropic mixing, to address this problem. Using a selective total correlation spectroscopy technique to excite and transfer magnetization from a resolved resonance, we demonstrate that the time dependence of this transfer to another resolved site depends linearly on the number of aliphatic carbons separating the two sites. This technique is applied to complex natural mixtures allowing the identification and quantification of the constituent fatty acids. The method has been applied to whole adipocytes demonstrating that it will be of great use in studies of whole tissues. PMID:24831341

  12. SAMPLING ARTIFACT ESTIMATES FOR ALKANES, HOPANES, AND ALIPHATIC CARBOXYLIC ACIDS

    EPA Science Inventory

    Sampling artifacts for molecular markers from organic speciation of particulate matter were investigated by analyzing forty-one samples collected in Philadelphia as a part of the Northeast Oxidant and Particulate Study (NEOPS). Samples were collected using a high volume sampler ...

  13. [Antioxidant and antitumor activity of dirhenium dicarboxylates in animals with guerin carcinoma].

    PubMed

    Leus, I V; Shamelashvili, K L; Skoryk, O D; Tretiak, S Iu; Golichenko, O A; Shtemenko, O V; Shtemenko, N I

    2012-01-01

    The antioxidant and anticancer properties of dirhenium dicarboxylates of cis- and transconfiguration with different organic ligands in a model of tumor growth (Guerin carcinoma) were studied. It was shown that compounds of different configuration had similar antitumor effect, and dirhenium (III) cis-dicarboxylates were characterized by higher antioxidant activity and degree of activation of erythrocyte superoxide dismutase (SOD) in comparison with trans-isomers. The dependence between the structure of dirhenium (III) dicarboxylates and their ability to activate erythrocyte SOD in the model of tumor growth was shown for the first time. The in vitro studies have shown that rhenium compounds of cis- and transconfiguration interacted similarly with erythrocyte SOD, changing the protein secondary structure. In contrast to trans-dicarboxylate, for cis-dicarboxylate the SOD-like activity was demonstrated to be on the first minutes of the xantine-oxidase reaction. The studied features of the interaction between rhenium compounds and SOD in vitro explain only partly the activation of SOD in experiments in vivo. The attempt is made to explain the differences in the mechanisms of antioxidant activity of dirhenium cis- and trans-dicarboxylates. PMID:22860404

  14. Indigenous aliphatic amines in the aqueously altered Orgueil meteorite

    NASA Astrophysics Data System (ADS)

    Aponte, José C.; Dworkin, Jason P.; Elsila, Jamie E.

    2015-10-01

    The CI1 Orgueil meteorite is a highly aqueously altered carbonaceous chondrite. It has been extensively studied, and despite its extensive degree of aqueous alteration and some documented instances of contamination, several indigenous organic compounds including amino acids, carboxylic acids, and nucleobases have been detected in its carbon-rich matrix. We recently developed a novel gas chromatographic method for the enantiomeric and compound-specific isotopic analyses of meteoritic aliphatic monoamines in extracts and have now applied this method to investigate the monoamine content in Orgueil. We detected 12 amines in Orgueil, with concentrations ranging from 1.1 to 332 nmol g-1 of meteorite and compared this amine content in Orgueil with that of the CM2 Murchison meteorite, which experienced less parent-body aqueous alteration. Methylamine is four times more abundant in Orgueil than in Murchison. As with other species, the amine content in Orgueil extracts shows less structural diversity than that in Murchison extracts. We measured the compound-specific stable carbon isotopic ratios (δ13C) for 5 of the 12 monoamines detected in Orgueil and found a range of δ13C values from -20 to +59‰. These δ13C values fall into the range of other meteoritic organic compounds, although they are 13C-depleted relative to their counterparts extracted from the Murchison meteorite. In addition, we measured the enantiomeric composition for the chiral monoamines (R)- and (S)-sec-butylamine in Orgueil, and found it was racemic within experimental error, in contrast with the L-enantiomeric excess found for its amino acid structural analog isovaline. The racemic nature of sec-butylamine in Orgueil was comparable to that previously observed in Murchison, and to other CM2 and CR2 carbonaceous chondrites measured in this work (ALH 83100 [CM1/2], LON 94101 [CM2], LEW 90500 [CM2], LAP 02342 [CR2], and GRA 95229 [CR2]). These results allow us to place some constraints on the effects of

  15. Iron-Catalyzed Oxyfunctionalization of Aliphatic Amines at Remote Benzylic C-H Sites.

    PubMed

    Mbofana, Curren T; Chong, Eugene; Lawniczak, James; Sanford, Melanie S

    2016-09-01

    We report the development of an iron-catalyzed method for the selective oxyfunctionalization of benzylic C(sp(3))-H bonds in aliphatic amine substrates. This transformation is selective for benzylic C-H bonds that are remote (i.e., at least three carbons) from the amine functional group. High site selectivity is achieved by in situ protonation of the amine with trifluoroacetic acid, which deactivates more traditionally reactive C-H sites that are α to nitrogen. The scope and synthetic utility of this method are demonstrated via the synthesis and derivatization of a variety of amine-containing, biologically active molecules. PMID:27529646

  16. Aliphatic alcohols in spirits inhibit phagocytosis by human monocytes.

    PubMed

    Pál, László; Árnyas, Ervin M; Bujdosó, Orsolya; Baranyi, Gergő; Rácz, Gábor; Ádány, Róza; McKee, Martin; Szűcs, Sándor

    2015-04-01

    A large volume of alcoholic beverages containing aliphatic alcohols is consumed worldwide. Previous studies have confirmed the presence of ethanol-induced immunosuppression in heavy drinkers, thereby increasing susceptibility to infectious diseases. However, the aliphatic alcohols contained in alcoholic beverages might also impair immune cell function, thereby contributing to a further decrease in microbicidal activity. Previous research has shown that aliphatic alcohols inhibit phagocytosis by granulocytes but their effect on human monocytes has not been studied. This is important as they play a crucial role in engulfment and killing of pathogenic microorganisms and a decrease in their phagocytic activity could lead to impaired antimicrobial defence in heavy drinkers. The aim of this study was to measure monocyte phagocytosis following their treatment with those aliphatic alcohols detected in alcoholic beverages. Monocytes were separated from human peripheral blood and phagocytosis of opsonized zymosan particles by monocytes treated with ethanol and aliphatic alcohols individually and in combination was determined. It was shown that these alcohols could suppress the phagocytic activity of monocytes in a concentration-dependent manner and when combined with ethanol, they caused a further decrease in phagocytosis. Due to their additive effects, it is possible that they may inhibit phagocytosis in a clinically meaningful way in alcoholics and episodic heavy drinkers thereby contribute to their increased susceptibility to infectious diseases. However, further research is needed to address this question.

  17. Ligand-controlled assembly of Cd(II) coordination polymers based on mixed ligands of naphthalene-dicarboxylate and dipyrido[3,2-d:2',3'-f]quinoxaline: From 0D+1D cocrystal, 2D rectangular network (4,4), to 3D PtS-type architecture

    SciTech Connect

    Liu Guocheng; Chen Yongqiang; Wang Xiuli Chen Baokuan; Lin Hongyan

    2009-03-15

    Three novel Cd(II) coordination polymers, namely, [Cd(Dpq)(1,8-NDC)(H{sub 2}O){sub 2}][Cd(Dpq)(1,8-NDC)].2H{sub 2}O (1), [Cd(Dpq)(1,4-NDC)(H{sub 2}O)] (2), and [Cd(Dpq)(2,6-NDC)] (3) have been obtained from hydrothermal reactions of cadmium(II) nitrate with the mixed ligands dipyrido [3,2-d:2',3'-f]quinoxaline (Dpq) and three structurally related naphthalene-dicarboxylate ligands [1,8-naphthalene-dicarboxylic acid (1,8-H{sub 2}NDC), 1,4-naphthalene-dicarboxylic acid (1,4-H{sub 2}NDC), and 2,6-naphthalene-dicarboxylic acid (2,6-H{sub 2}NDC)]. Single-crystal X-ray diffraction analysis reveals that the three polymers exhibit novel structures due to different naphthalene-dicarboxylic acid. Compound 1 is a novel cocrystal of left- and right-handed helical chains and binuclear complexes and ultimately packed into a 3D supramolecular structure through hydrogen bonds and {pi}-{pi} stacking interactions. Compound 2 shows a 2D rectangular network (4,4) bridged by 1,4-NDC with two kinds of coordination modes and ultimately packed into a 3D supramolecular structure through inter-layer {pi}-{pi} stacking interactions. Compound 3 is a new 3D coordination polymer with distorted PtS-type network. In addition, the title compounds exhibit blue/green emission in solid state at room temperature. - Graphical abstract: Three novel Cd(II) compounds have been synthesized under hydrothermal conditions exhibiting a systematic variation of architecture by the employment of three structurally related naphthalene-dicarboxylate ligands.

  18. Hyperbranched Aliphatic Polyester Modified Activated Carbon Particles with Homogenized Surface Groups

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Zhang, Liuxue

    The hyperbranched aliphatic polyester grafted activated carbon (HAPE-AC), was successfully prepared by the simple "one-pot" method. The surface functional groups of commercial activated carbon particles were homogenized to hydroxyl groups by being oxidized with nitric acid and then reduced with lithium tetrahydroaluminate (LiAlH4) at first. Secondly, the surface hydroxyl groups were used as the active sites for the solution polycondensation of the AB2 monomer, 2, 2-bis(hydroxymethyl)propionic acid (bis-MPA), with the catalysis of p-toluenesulfonic acid (p-TSA). The homogenization of the surface groups of the activated carbon particles and the graft polymerization of the hyperbranched aliphatic polyester were investigated by X-ray photoelectron spectroscopy (XPS) technique. The products were also characterized with Fourier transform infrared (FT-IR) and scanning electron microscope (SEM). The competitive adsorption properties of the products toward the heavy metal ions (Cu(II), Hg(II), Zn(II), and Cd(II)) also proved the translations of the surface groups.

  19. Topological Analysis of DcuA, an Anaerobic C4-Dicarboxylate Transporter of Escherichia coli

    PubMed Central

    Golby, Paul; Kelly, David J.; Guest, John R.; Andrews, Simon C.

    1998-01-01

    Escherichia coli possesses three independent anaerobic C4-dicarboxylate transport systems encoded by the dcuA, dcuB, and dcuC genes. The dcuA and dcuB genes encode related integral inner-membrane proteins, DcuA and DcuB (433 and 446 amino acid residues), which have 36% amino acid sequence identity. A previous amino acid sequence-based analysis predicted that DcuA and DcuB contain either 12 or 14 transmembrane helices, with the N and C termini located in the cytoplasm or periplasm (S. Six, S. C. Andrews, G. Unden, and J. R. Guest, J. Bacteriol. 176:6470–6478, 1994). These predictions were tested by constructing and analyzing 66 DcuA-BlaM fusions in which C terminally truncated forms of DcuA are fused to a β-lactamase protein lacking the N-terminal signal peptide. The resulting topological model differs from those previously predicted. It has just 10 transmembrane helices and a central, 80-residue cytoplasmic loop between helices 5 and 6. The N and C termini are located in the periplasm and the predicted orientation is consistent with the “positive-inside rule.” Two highly hydrophobic segments are not membrane spanning: one is in the cytoplasmic loop; the other is in the C-terminal periplasmic region. The topological model obtained for DcuA can be applied to DcuA homologues in other bacteria as well as to DcuB. Overproduction of DcuA to 15% of inner-membrane protein was obtained with the lacUV5-promoter-based plasmid, pYZ4. PMID:9733683

  20. Metal(II) complexes synthesized based on quinoline-2,3-dicarboxylate as electrocatalysts for the degradation of methyl orange.

    PubMed

    Gong, Yun; Zhang, Miao Miao; Qin, Jian Bo; Li, Jian; Meng, Jiang Ping; Lin, Jian Hua

    2014-06-14

    Based on quinoline-2,3-dicarboxylic acid (H2L), two metal(II) complexes formulated as MnL(phen)(H2O)·H2O (phen = 1,10-phenanthroline) (1) and Co(HL)2(PPA)·4H2O (PPA = N(1),N(4)-di(pyridin-4-yl)terephthalamide) (2) were synthesized and structurally characterized by single-crystal X-ray diffraction. Both complexes 1 and 2 exhibit one-dimensional (1D) chain-like structures, in which stable five-membered rings are observed. Different chains are linked by strong π-π stacking interactions into a three-dimensional (3D) supramolecular architecture. Both complexes can increase the degradation rate of methyl orange (MO), which is expected to be associated with their electrocatalytic activities for the H2 evolution reaction from water. PMID:24741675

  1. Determinants of substrate and cation transport in the human Na+/dicarboxylate cotransporter NaDC3.

    PubMed

    Schlessinger, Avner; Sun, Nina N; Colas, Claire; Pajor, Ana M

    2014-06-13

    Metabolic intermediates, such as succinate and citrate, regulate important processes ranging from energy metabolism to fatty acid synthesis. Cytosolic concentrations of these metabolites are controlled, in part, by members of the SLC13 gene family. The molecular mechanism underlying Na(+)-coupled di- and tricarboxylate transport by this family is understood poorly. The human Na(+)/dicarboxylate cotransporter NaDC3 (SLC13A3) is found in various tissues, including the kidney, liver, and brain. In addition to citric acid cycle intermediates such as α-ketoglutarate and succinate, NaDC3 transports other compounds into cells, including N-acetyl aspartate, mercaptosuccinate, and glutathione, in keeping with its dual roles in cell nutrition and detoxification. In this study, we construct a homology structural model of NaDC3 on the basis of the structure of the Vibrio cholerae homolog vcINDY. Our computations are followed by experimental testing of the predicted NaDC3 structure and mode of interaction with various substrates. The results of this study show that the substrate and cation binding domains of NaDC3 are composed of residues in the opposing hairpin loops and unwound portions of adjacent helices. Furthermore, these results provide a possible explanation for the differential substrate specificity among dicarboxylate transporters that underpin their diverse biological roles in metabolism and detoxification. The structural model of NaDC3 provides a framework for understanding substrate selectivity and the Na(+)-coupled anion transport mechanism by the human SLC13 family and other key solute carrier transporters.

  2. Syntheses, characterization, antimicrobial and cytotoxic activities of pyridine-2,5-dicarboxylate complexes with 1,10-phenanthroline.

    PubMed

    Colak, Alper Tolga; Oztopcu-Vatan, Pinar; Colak, Ferdag; Akduman, Demet; Kabadere, Selda; Uyar, Ruhi

    2013-10-01

    In this study, four mononuclear M(II)-pyridine-2,5-dicarboxylate (M = Co(II), Ni(II), Cu(II) and Zn(II) complexes with pyridine-2,5-dicarboxylic acid or isocinchomeronic acid, 1,10-phenanthroline (phen), [Co(Hpydc)(2)(phen)]·H(2)O (1), [Ni(pydc)(phen)(2)]·6.5H(2)O (2) [Cu(pydc)(phen)(H(2)O)(2)] (3) and [Zn(pydc)(phen)(H(2)O)(2)]·H(2)O (4) have been synthesized. Elemental, thermal and mass analyses, molar conductance, magnetic susceptibilities, IR and UV/vis spectroscopic studies have been performed to characterize the complexes. Subsequently, these ligands and complexes were tested for antimicrobial activity by disc diffusion method on Gram positive, negative bacteria and yeast. In addition, cytotoxic activity tests were performed on rat glioma (C6) cells by MTT viability assay for 24 and 48 h. Antimicrobial activity results demonstrated that when compared to the standard antibiotics, phen displayed the most effective antimicrobial effect. The effect of synthesized complexes was close to phen or less. Cytotoxic activity results showed that IC(50) value of phen was determined as 31 μM for 48 h. (1) and (2) compared to the alone ligand had less toxic activity. IC(50) values of (3) for 24 and 48 h treatments were 2.5 and 0.6 μM, respectively. IC(50) value of (4) for 48 h was 15 μM. In conclusion, phen, (3) and (4) may be useful as antibacterial and antiproliferative agents in the future. PMID:23669312

  3. Composition and sources of aliphatic lipids and sterols in sediments of a tropical island, southern South China Sea: preliminary assessment.

    PubMed

    Mohd Tahir, N; Pang, S Y; Abdullah, N A; Suratman, S

    2013-12-01

    Near-shore surface sediment was collected from five stations off Redang Island located on the eastern coast of Peninsular Malaysia. Freeze-dried sediments were Soxhlet extracted and then fractionated using column chromatography into aliphatic and polar fractions. Determination of these fractions was carried out using gas chromatography mass spectrometry. The concentration of total resolved aliphatic hydrocarbons in sediments ranged from 157 to 308 ng/g. The distribution of aliphatic fraction showed the presence of n-alkanes ranging from nC15 to nC33 with a minor odd-to-even predominance exhibiting carbon maximum, depending on station, at nC17, nC26, nC29 or nC31. Calculation of Carbon Preference Index (CPI) for CPI(15-33) gave values ranging from 1.09 to 1.46. n-Alkanol in all sediment exhibits even-to-odd carbon predominance ranging from nC16 to nC28 and maximising at nC22. n-Fatty acids distribution ranged from nC14 to nC24 with a dominant maximum at nC16 and exhibiting high values of short chain fatty acids (≤nC20) to long chain fatty acids (>nC20) ratios. Unsaturated fatty acids, particularly nC16:1 and nC18:1 is also ubiquitous in all samples. Cholesterol is the most abundant compound amongst the sterol group ranging from 42.8 to 62.6% of the total sterols. β-Sitosterol, brassicasterol and stigmasterol, are also present but of relatively lower amount. These observations suggest that the aliphatic lipids and sterols in the study area originate, mainly, from biogenic sources of marine microbial with minor contribution from epiticular waxes of terrestrial plants.

  4. Composition and sources of aliphatic lipids and sterols in sediments of a tropical island, southern South China Sea: preliminary assessment.

    PubMed

    Mohd Tahir, N; Pang, S Y; Abdullah, N A; Suratman, S

    2013-12-01

    Near-shore surface sediment was collected from five stations off Redang Island located on the eastern coast of Peninsular Malaysia. Freeze-dried sediments were Soxhlet extracted and then fractionated using column chromatography into aliphatic and polar fractions. Determination of these fractions was carried out using gas chromatography mass spectrometry. The concentration of total resolved aliphatic hydrocarbons in sediments ranged from 157 to 308 ng/g. The distribution of aliphatic fraction showed the presence of n-alkanes ranging from nC15 to nC33 with a minor odd-to-even predominance exhibiting carbon maximum, depending on station, at nC17, nC26, nC29 or nC31. Calculation of Carbon Preference Index (CPI) for CPI(15-33) gave values ranging from 1.09 to 1.46. n-Alkanol in all sediment exhibits even-to-odd carbon predominance ranging from nC16 to nC28 and maximising at nC22. n-Fatty acids distribution ranged from nC14 to nC24 with a dominant maximum at nC16 and exhibiting high values of short chain fatty acids (≤nC20) to long chain fatty acids (>nC20) ratios. Unsaturated fatty acids, particularly nC16:1 and nC18:1 is also ubiquitous in all samples. Cholesterol is the most abundant compound amongst the sterol group ranging from 42.8 to 62.6% of the total sterols. β-Sitosterol, brassicasterol and stigmasterol, are also present but of relatively lower amount. These observations suggest that the aliphatic lipids and sterols in the study area originate, mainly, from biogenic sources of marine microbial with minor contribution from epiticular waxes of terrestrial plants. PMID:23856812

  5. Catalytic Asymmetric Hydroamination of Unactivated Internal Olefins to Aliphatic Amines

    PubMed Central

    Yang, Yang; Shi, Shi-Liang; Niu, Dawen; Liu, Peng; Buchwald, Stephen L.

    2015-01-01

    Catalytic assembly of enantiopure aliphatic amines from abundant and readily available precursors has long been recognized as a paramount challenge in synthetic chemistry. Herein, we describe a mild and general copper-catalyzed hydroamination that effectively converts unactivated internal olefins, an important yet unexploited class of abundant feedstock chemicals, into highly enantioenriched α-branched amines (≥ 96% enantiomeric excess) featuring two minimally differentiated aliphatic substituents. This method provides a powerful means to access a broad range of advanced, highly functionalized enantioenriched amines of interest in pharmaceutical research and other areas. PMID:26138973

  6. Properties of yeast Saccharomyces cerevisiae plasma membrane dicarboxylate transporter.

    PubMed

    Aliverdieva, D A; Mamaev, D V; Bondarenko, D I; Sholtz, K F

    2006-10-01

    Transport of succinate into Saccharomyces cerevisiae cells was determined using the endogenous coupled mitochondrial succinate oxidase system. The dependence of succinate oxidation rate on the substrate concentration was a curve with saturation. At neutral pH the K(m) value of the mitochondrial "succinate oxidase" was fivefold less than that of the cellular "succinate oxidase". O-Palmitoyl-L-malate, not penetrating across the plasma membrane, completely inhibited cell respiration in the presence of succinate but not glucose or pyruvate. The linear inhibition in Dixon plots indicates that the rate of succinate oxidation is limited by its transport across the plasmalemma. O-Palmitoyl-L-malate and L-malate were competitive inhibitors (the K(i) values were 6.6 +/- 1.3 microM and 17.5 +/- 1.1 mM, respectively). The rate of succinate transport was also competitively inhibited by the malonate derivative 2-undecyl malonate (K(i) = 7.8 +/- 1.2 microM) but not phosphate. Succinate transport across the plasma membrane of S. cerevisiae is not coupled with proton transport, but sodium ions are necessary. The plasma membrane of S. cerevisiae is established to have a carrier catalyzing the transport of dicarboxylates (succinate and possibly L-malate and malonate).

  7. Transport of C5 dicarboxylate compounds by Pseudomonas putida.

    PubMed Central

    Edwards, W V; Sando, J J; Hartline, R A

    1979-01-01

    Induced glutarate and 2-oxoglutarate uptake and transport by Pseudomonas putida were investigated in whole cells and membrane vesicles, respectively. Uptake of 2-oxoglutarate, but not glutarate, was against a concentration gradient to 1.7-fold greater than the initial extracellular concentration. Membrane vesicles transported 2-oxoglutarate and glutarate against gradients to intramembrane concentrations fivefold greater than the initial extravesicle concentrations. The rates of transport of both compounds were greatest in the presence of the artificial electron donor system phenazine methosulfate-ascorbate. Malate and D-lactate were the only naturally occurring compounds that served as electron donors. Uptake and transport were inhibited by KCN, NaN3, and 2,2-dinitrophenol. Kinetic parameters of transport were: glutarate, apparent Km--1.22 mM, Vmax--400 nmol/min per mg of membrane protein; 2-oxoglutarate, apparent Km--131 microM, Vmax--255 nmol/min per mg of membrane protein. Studies of competitive inhibition indicated a common system for transport of five C5 dicarboxylate compounds. The apparent Km and Ki values with 2-oxoglutarate as a substrate placed the substrate affinity for transport in the order 2-oxoglutarate greater than glutarate greater than D-2-hydroxyglutarate and L-2-hydroxyglutarate greater than glutaconate. PMID:479107

  8. Kinetic and molecular orbital analyses of dicarboxylic acylcarnitine methylesterification show that derivatization may affect the screening of newborns by tandem mass spectrometry.

    PubMed

    Maeda, Yasuhiro; Nakajima, Yoko; Gotoh, Kana; Hotta, Yuji; Kataoka, Tomoya; Sugiyama, Naruji; Shirai, Naohiro; Ito, Tetsuya; Kimura, Kazunori

    2016-01-01

    Newborns are routinely screened for organic acidemias by acylcarnitine analysis. We previously reported the partial catalytic methylesterification of dicarboxylic acylcarnitines by benzenesulfonic acid moiety in the solid extraction cartridge during extraction from serum. Since the diagnosis of organic acidemias by tandem mass spectrometry is affected by the higher molecular weight of these derivatized acylcarnitines, we investigated the methylesterification conditions. The kinetic constants for the methylesterification of carboxyl groups on the acyl and carnitine sides of carnitine were 2.5 and 0.24h(-1), respectively. The physical basis underlying this difference in methylesterification rates was clarified theoretically, illustrating that methylesterification during extraction proceeds easily and must be prevented.

  9. Kinetic and molecular orbital analyses of dicarboxylic acylcarnitine methylesterification show that derivatization may affect the screening of newborns by tandem mass spectrometry.

    PubMed

    Maeda, Yasuhiro; Nakajima, Yoko; Gotoh, Kana; Hotta, Yuji; Kataoka, Tomoya; Sugiyama, Naruji; Shirai, Naohiro; Ito, Tetsuya; Kimura, Kazunori

    2016-01-01

    Newborns are routinely screened for organic acidemias by acylcarnitine analysis. We previously reported the partial catalytic methylesterification of dicarboxylic acylcarnitines by benzenesulfonic acid moiety in the solid extraction cartridge during extraction from serum. Since the diagnosis of organic acidemias by tandem mass spectrometry is affected by the higher molecular weight of these derivatized acylcarnitines, we investigated the methylesterification conditions. The kinetic constants for the methylesterification of carboxyl groups on the acyl and carnitine sides of carnitine were 2.5 and 0.24h(-1), respectively. The physical basis underlying this difference in methylesterification rates was clarified theoretically, illustrating that methylesterification during extraction proceeds easily and must be prevented. PMID:26597535

  10. A Dicarboxylate Transporter, LjALMT4, Mainly Expressed in Nodules of Lotus japonicus.

    PubMed

    Takanashi, Kojiro; Sasaki, Takayuki; Kan, Tomohiro; Saida, Yuka; Sugiyama, Akifumi; Yamamoto, Yoko; Yazaki, Kazufumi

    2016-07-01

    Legume plants can establish symbiosis with soil bacteria called rhizobia to obtain nitrogen as a nutrient directly from atmospheric N2 via symbiotic nitrogen fixation. Legumes and rhizobia form nodules, symbiotic organs in which fixed-nitrogen and photosynthetic products are exchanged between rhizobia and plant cells. The photosynthetic products supplied to rhizobia are thought to be dicarboxylates but little is known about the movement of dicarboxylates in the nodules. In terms of dicarboxylate transporters, an aluminum-activated malate transporter (ALMT) family is a strong candidate responsible for the membrane transport of carboxylates in nodules. Among the seven ALMT genes in the Lotus japonicus genome, only one, LjALMT4, shows a high expression in the nodules. LjALMT4 showed transport activity in a Xenopus oocyte system, with LjALMT4 mediating the efflux of dicarboxylates including malate, succinate, and fumarate, but not tricarboxylates such as citrate. LjALMT4 also mediated the influx of several inorganic anions. Organ-specific gene expression analysis showed LjALMT4 mRNA mainly in the parenchyma cells of nodule vascular bundles. These results suggest that LjALMT4 may not be involved in the direct supply of dicarboxylates to rhizobia in infected cells but is responsible for supplying malate as well as several anions necessary for symbiotic nitrogen fixation, via nodule vasculatures. PMID:27183039

  11. Functional characterization of a Na(+)-coupled dicarboxylate transporter from Bacillus licheniformis.

    PubMed

    Strickler, Melodie A; Hall, Jason A; Gaiko, Olga; Pajor, Ana M

    2009-12-01

    The Na(+)-coupled dicarboxylate transporter, SdcL, from Bacillus licheniformis is a member of the divalent anion/Na(+) symporter (DASS) family that includes the bacterial Na(+)/dicarboxylate cotransporter SdcS (from Staphyloccocus aureus) and the mammalian Na(+)/dicarboxylate cotransporters, NaDC1 and NaDC3. The transport properties of SdcL produced in Escherichia coli are similar to those of its prokaryotic and eukaryotic counterparts, involving the Na(+)-dependent transport of dicarboxylates such as succinate or malate across the cytoplasmic membrane with a K(m) of approximately 6 microM. SdcL may also transport aspartate, alpha-ketoglutarate and oxaloacetate with low affinity. The cotransport of Na(+) and dicarboxylate by SdcL has an apparent stoichiometry of 2:1, and a K(0.5) for Na(+) of 0.9 mM. Our findings represent the characterization of another prokaryotic protein of the DASS family with transport properties similar to its eukaryotic counterparts, but with a broader substrate specificity than other prokaryotic DASS family members. The broader range of substrates carried by SdcL may provide insight into domains of the protein that allow a more flexible or larger substrate binding pocket.

  12. Applicability of the theory of thermodynamic similarity to predict the enthalpies of vaporization of aliphatic aldehydes

    NASA Astrophysics Data System (ADS)

    Esina, Z. N.; Korchuganova, M. R.

    2015-06-01

    The theory of thermodynamic similarity is used to predict the enthalpies of vaporization of aliphatic aldehydes. The predicted data allow us to calculate the phase diagrams of liquid-vapor equilibrium in a binary water-aliphatic aldehyde system.

  13. Coligand-regulated assembly, fluorescence, and magnetic properties of Co(II) and Cd(II) complexes with a non-coplanar dicarboxylate

    SciTech Connect

    Xin, Ling-Yun; Liu, Guang-Zhen; Ma, Lu-Fang; Wang, Li-Ya

    2013-10-15

    A non-coplanar dicarboxylate ndca (H{sub 2}ndca=5-norbornene-2,3-dicarboxylic acid), combining with various dipyridyl-typed tectons, constructs six Cd(II)/Co(II) coordination polymers under hydrothermal conditions, namely [Co(ndca)(H{sub 2}O)]{sub n} (1), ([Co(ndca)(bpe)(H{sub 2}O)]·H{sub 2}O){sub n} (2), [Co(ndca)(bpa){sub 0.5}(H{sub 2}O)]{sub n} (3), [Cd(ndca)(bpe)(H{sub 2}O)]{sub n} (4), ([Cd(ndca)(bpa)(H{sub 2}O)]·0.5H{sub 2}O){sub n} (5), and ([Cd(ndca)(bpp) (H{sub 2}O)]·H{sub 2}O){sub n} (6) (bpe=1,2-di(4-pyridyl)ethylene, bpa=1,2-bi(4-pyridyl)ethane, and bpp=1,3-bis(4-pyridyl)propane). All these compounds contain various metal(II)–carboxylate motifs, including carboxylate binuclear (2, 4, 5), carboxylate chain (1, 6) and carboxylate layer (3), which are further extended by dipyridyl-typed coligands to afford a vast diversity of the structures with 2D pyknotic layers (1, 6), 2D open layer (5), 2D→3D interpenetrated networks (2,4), and 3D pillared-layer framework (3), respectively. In addition, fluorescent spectra of Cd(II) complexes and magnetic properties of Co(II) complexes are also given. - Graphical abstract: Six various cadmium(II)/cobalt(II)–organic frameworks were constructed by 5-norbornene-2,3-dicarboxylic acid and different bis(pyridine) rod-like tectons, and Cd (II) complexes exhibit blue–violet emissions, whereas Co (II) complexes show antiferromagnetic behaviours. Display Omitted.

  14. Selective stabilization of aliphatic organic carbon by iron oxide

    PubMed Central

    Adhikari, Dinesh; Yang, Yu

    2015-01-01

    Stabilization of organic matter in soil is important for natural ecosystem to sequestrate carbon and mitigate greenhouse gas emission. It is largely unknown what factors govern the preservation of organic carbon in soil, casting shadow on predicting the response of soil to climate change. Iron oxide was suggested as an important mineral preserving soil organic carbon. However, ferric minerals are subject to reduction, potentially releasing iron and decreasing the stability of iron-bound organic carbon. Information about the stability of iron-bound organic carbon in the redox reaction is limited. Herein, we investigated the sorptive interactions of organic matter with hematite and reductive release of hematite-bound organic matter. Impacts of organic matter composition and conformation on its sorption by hematite and release during the reduction reaction were analyzed. We found that hematite-bound aliphatic carbon was more resistant to reduction release, although hematite preferred to sorb more aromatic carbon. Resistance to reductive release represents a new mechanism that aliphatic soil organic matter was stabilized by association with iron oxide. Selective stabilization of aliphatic over aromatic carbon can greatly contribute to the widely observed accumulation of aliphatic carbon in soil, which cannot be explained by sorptive interactions between minerals and organic matter. PMID:26061259

  15. Triphosgene–Amine Base Promoted Chlorination of Unactivated Aliphatic Alcohols

    PubMed Central

    Villalpando, Andrés; Ayala, Caitlan E.; Watson, Christopher B.; Kartika, Rendy

    2014-01-01

    Unactivated α-branched primary and secondary aliphatic alcohols have been successfully transformed into their corresponding alkyl chlorides in high yields upon treatment with a mixture of triphosgene and pyridine in dichloromethane at reflux. These mild chlorination conditions are high yielding, stereospecific, and well tolerated by numerous sensitive functionalities. Furthermore, no nuisance waste products are generated in the course of the reactions. PMID:23496045

  16. Cloud condensation nuclei activity of aliphatic amine secondary aerosol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical). The resulting particle composition can contain both secondary organic aerosol (SOA) and inorganic salts. The fraction of organic to inorganic materials in the particulate ...

  17. Selective stabilization of aliphatic organic carbon by iron oxide.

    PubMed

    Adhikari, Dinesh; Yang, Yu

    2015-01-01

    Stabilization of organic matter in soil is important for natural ecosystem to sequestrate carbon and mitigate greenhouse gas emission. It is largely unknown what factors govern the preservation of organic carbon in soil, casting shadow on predicting the response of soil to climate change. Iron oxide was suggested as an important mineral preserving soil organic carbon. However, ferric minerals are subject to reduction, potentially releasing iron and decreasing the stability of iron-bound organic carbon. Information about the stability of iron-bound organic carbon in the redox reaction is limited. Herein, we investigated the sorptive interactions of organic matter with hematite and reductive release of hematite-bound organic matter. Impacts of organic matter composition and conformation on its sorption by hematite and release during the reduction reaction were analyzed. We found that hematite-bound aliphatic carbon was more resistant to reduction release, although hematite preferred to sorb more aromatic carbon. Resistance to reductive release represents a new mechanism that aliphatic soil organic matter was stabilized by association with iron oxide. Selective stabilization of aliphatic over aromatic carbon can greatly contribute to the widely observed accumulation of aliphatic carbon in soil, which cannot be explained by sorptive interactions between minerals and organic matter. PMID:26061259

  18. Introducing Aliphatic Substitution with a Discovery Experiment Using Competing Electrophiles

    ERIC Educational Resources Information Center

    Curran, Timothy P.; Mostovoy, Amelia J.; Curran, Margaret E.; Berger, Clara

    2016-01-01

    A facile, discovery-based experiment is described that introduces aliphatic substitution in an introductory undergraduate organic chemistry curriculum. Unlike other discovery-based experiments that examine substitution using two competing nucleophiles with a single electrophile, this experiment compares two isomeric, competing electrophiles…

  19. A thermostable transketolase evolved for aliphatic aldehyde acceptors.

    PubMed

    Yi, Dong; Saravanan, Thangavelu; Devamani, Titu; Charmantray, Franck; Hecquet, Laurence; Fessner, Wolf-Dieter

    2015-01-11

    Directed evolution of the thermostable transketolase from Geobacillus stearothermophilus based on a pH-based colorimetric screening of smart libraries yielded several mutants with up to 16-fold higher activity for aliphatic aldehydes and high enantioselectivity (>95% ee) in the asymmetric carboligation step. PMID:25415647

  20. A novel chiral aliphatic-aromatic diamine promoted direct, highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins under solvent-free conditions.

    PubMed

    Miao, Shifeng; Bai, Jinjin; Yang, Jin; Zhang, Yawen

    2010-10-01

    A series of new highly efficient chiral aliphatic-aromatic diamine catalysts have been designed and successfully applied to the asymmetric Michael addition of cyclohexanone with nitroolefins under solvent-free conditions without any acidic additives. The desired adducts were obtained in high yields with excellent enantio- and diastereoselectivities of syn products (up to >99% ee, >99:1 dr).

  1. Synthesis, structure, and photoluminescence of ZnII and CdII coordination complexes constructed by structurally related 5,6-substituted pyrazine-2,3-dicarboxylate ligands

    NASA Astrophysics Data System (ADS)

    Li, Yun-Wu; Tao, Ying; Hu, Tong-Liang

    2012-08-01

    Aiming at exploring the effect of substituting groups of three structurally related ligands, 5,6-diethyl-pyrazine-2,3-dicarboxylic acid (H2L1), 5,6-diphenyl-pyrazine-2,3-dicarboxylic acid (H2L2), and dibenzo[f,h]quinoxaline-2,3-dicarboxylic acid (H2L3), seven new coordination polymers constructed from these three substituted dicarboxylate ligands, {[Zn(L1)(H2O)3]·2H2O}∞ (1), {[Cd2(L2ʹ)4(H2O)]·3H2O}∞ (2), [Zn(L2)(CH3OH)]∞ (3), {[Zn(L2)(H2O)2]·H2O}∞ (4), {[Zn(L2ʹ)]·H2O}∞ (5), [Zn2(L3)(DMF)4]∞(6), [Zn(L3)(2,2ʹ-bipy)(H2O)]∞(7), have been prepared and structurally characterized. 1 is a 1D chain structure in which ZnII ion is six-coordinated with octahedron geometry. 2 is also a 1D chain structure in which there are two crystallographically independent CdII ions in the asymmetric unit and exist transformative L2ʹ ligands in the resulting complex. 3 and 4 both possess 2D layer network with the same (4, 82) topology, while the two complexes take different coordination modes during the forming of the compounds. 5 has a 1D chain structure based on the transformative L2ʹ ligand in which ZnII ion is five-coordinated with bipyramidal geometry. 6 and 7 both have 1D chain structure constructed from L3 ligand. Thereinto, ZnII ion in 6 is five-coordinated by three oxygen atoms from two individual L3 ligands and two oxygen atoms from two DMF molecules. While in 7 there are also five coordination sites occupied by two carboxylate oxygen atoms from two L3 ligands. In addition, the compounds are characterized by elemental analysis, IR spectra. The luminescent properties of the compounds are also discussed and exhibit strong fluorescent emissions in the solid state.

  2. 40 CFR 721.10608 - Aliphatic diisocyanate polymer with alkanediol and alkylglycol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aliphatic diisocyanate polymer with... Significant New Uses for Specific Chemical Substances § 721.10608 Aliphatic diisocyanate polymer with.... (1) The chemical substance identified generically as aliphatic diisocyanate polymer with...

  3. 40 CFR 721.10608 - Aliphatic diisocyanate polymer with alkanediol and alkylglycol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aliphatic diisocyanate polymer with... Significant New Uses for Specific Chemical Substances § 721.10608 Aliphatic diisocyanate polymer with.... (1) The chemical substance identified generically as aliphatic diisocyanate polymer with...

  4. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polyaziridinyl ester of an aliphatic... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  5. Compositions and sources of extractable organic matter in Mesopotamian marshland surface sediments of Iraq. I: aliphatic lipids

    NASA Astrophysics Data System (ADS)

    Rushdi, Ahmed I.; Douabul, Ali A.; Mohammed, Sama Samir; Simoneit, Bernd R. T.

    2006-08-01

    Shallow surface sediment samples from the Mesopotamian marshlands of Iraq were collected and analyzed to determine the distribution, concentrations and sources of aliphatic lipid compounds ( n-alkanes, n-alkanols, n-alkanoic acids, and methyl n-alkanoates) and molecular markers of petroleum in these wetlands. The sediments were collected using a stainless steel sediment corer, dried, extracted with a dichloromethane/methanol mixture and then analyzed by gas chromatography-mass spectrometry (GC MS). The aliphatic lipid compounds included n-alkanes, n-alkanoic acids, n-alkanols and methyl n-alkanoates with concentrations ranged from 6.8 to 31.1 μg/g, 4.1 to 5.0 μg/g, 5.9 to 7.7 μg/g and from 0.3 to 5.9 μg/g, respectively. The major sources of aliphatic lipids were natural from waxes of higher plants (24 30%) and microbial residues (42 30%), with a significant contribution from anthropogenic sources (27 30%, petroleum), based on the organic geochemical parameters and indices. Further studies are needed to characterize the rate, accumulation and transformation of various organic matter sources before and after re-flooding of these wetlands.

  6. Biodegradation of Aliphatic-Aromatic Copolyesters by Thermomonospora fusca and Other Thermophilic Compost Isolates

    PubMed Central

    Kleeberg, Ilona; Hetz, Claudia; Kroppenstedt, Reiner Michael; Müller, Rolf-Joachim; Deckwer, Wolf-Dieter

    1998-01-01

    Random aliphatic-aromatic copolyesters synthesized from 1,4-butanediol, adipic acid, and terephthalic acid (BTA) have excellent thermal and mechanical properties and are biodegradable by mixed cultures (e.g., in compost). Over 20 BTA-degrading strains were isolated by using compost as a microbial source. Among these microorganisms, thermophilic actinomycetes obviously play an outstanding role and appear to dominate the initial degradation step. Two actinomycete strains exhibited about 20-fold higher BTA degradation rates than usually observed in a common compost test. These isolates were identified as Thermomonospora fusca strains. They appeared to be particularly suitable for establishment of rapid degradation tests and were used in comparative studies on the biodegradation of various polyesters. PMID:9572944

  7. The mitochondrial dicarboxylate and 2-oxoglutarate carriers do not transport glutathione.

    PubMed

    Booty, Lee M; King, Martin S; Thangaratnarajah, Chancievan; Majd, Homa; James, Andrew M; Kunji, Edmund R S; Murphy, Michael P

    2015-02-27

    Glutathione carries out vital protective roles within mitochondria, but is synthesised in the cytosol. Previous studies have suggested that the mitochondrial dicarboxylate and 2-oxoglutarate carriers were responsible for glutathione uptake. We set out to characterise the putative glutathione transport by using fused membrane vesicles of Lactococcus lactis overexpressing the dicarboxylate and 2-oxoglutarate carriers. Although transport of the canonical substrates could be measured readily, an excess of glutathione did not compete for substrate uptake nor could transport of glutathione be measured directly. Thus these mitochondrial carriers do not transport glutathione and the identity of the mitochondrial glutathione transporter remains unknown.

  8. Examining the Amine Functionalization in Dicarboxylates: Photoelectron Spectroscopy and Theoretical Studies of Aspartate and Glutamate

    SciTech Connect

    Deng, Shihu; Hou, Gao-Lei; Kong, Xiangyu; Valiev, Marat; Wang, Xue B.

    2014-06-30

    Aspartate (Asp2-) and Glutamate (Glu2-), two doubly charged conjugate bases of the corresponding amino acids were investigated using low temperature negative ion photoelectron spectroscopy (NIPES) and ab-initio calculations. The effect of amine functionalization was studied by a direct comparison to the parent dicarboxylate species (-CO2–(CH2)n–CO2-, DCn2-) -- succinate (DC22-) and propionate (DC32-). Experimentally the addition of amine group for n = 2 case (DC22-, Asp2-) significantly improves the stability of the resultant Asp2- dianionic species, albeit that NIPES shows only a small increase in adiabatic electron detachment energy (ADE) (+0.05eV). In contrast, for n = 3 (DC32-, Glu2-), much larger ADE increase is observed (+0.15eV). Similar results are obtained through ab-initio calculations. The latter indicates that increased stability of Asp2- can be attributed to the lowering of the energy of singlet dianion state due to hydrogen bonding effects. The effect of the amino group on the doublet monoanion state is more complicated, and results in the weakening of the binding of the adjacent carboxylate group due to electronic structure resonance effects. This conclusion is confirmed by the analysis of NIPES results that show enhanced production of near zero kinetic energy electrons observed experimentally for amine-functionalized species.

  9. Two three-dimensional coordination polymers of lead(II) with iminodiacetate and naphthalene-dicarboxylate anions: Synthesis, characterization and luminescence behavior

    SciTech Connect

    Hazari, Debdoot; Jana, Swapan Kumar; Fleck, Michel; Zangrando, Ennio; Dalai, Sudipta

    2014-11-15

    Two lead(II) compounds [Pb{sub 3}(idiac){sub 3}(phen){sub 2}(H{sub 2}O)]·2(H{sub 2}O) (1) and [Pb(ndc)]{sub n} (2), where H{sub 2}idiac=iminodiacetic acid, phen=1,10-phenanthroline and H{sub 2}ndc=naphthalene-2,6-dicarboxylic acid, have been synthesized and structurally characterized. Single crystal X-ray diffraction analysis showed that compound 1 is a discrete trinuclear complex (of two-fold symmetry) which evolves to a supramolecular 3D network via π–π interactions, while in compound 2 the naphthalene dicarboxylate anion act as a linker to form a three dimensional architecture, where the anion adopts a bis-(bidentate bridging) coordination mode connecting four Pb(II) centers. The photoluminescence property of the two complexes has been studied. - graphical abstract: Two new topologically different 1D coordination polymers formed by Pb{sub 4} clusters have been synthesized and characterized by x-ray analysis. The luminescence and thermal properties have been studied. - Highlights: • 1 is a trinuclear complex of Pb(II) growing to 3D network via weak interactions. • In 1, layers of (4,4) rhomboidal topology are identified. • In 2, the ndc anion adopts interesting bis-(bidentate bridging) coordination. • In 2, network is reinforced by C–H…π-ring interactions between the ndc rings.

  10. Safety in the Chemical Laboratory: Nitric Acid, Nitrates, and Nitro Compounds.

    ERIC Educational Resources Information Center

    Bretherick, Leslie

    1989-01-01

    Discussed are the potential hazards associated with nitric acid, inorganic and organic nitrate salts, alkyl nitrates, acyl nitrates, aliphatic nitro compounds, aromatic nitro compounds, and nitration reactions. (CW)

  11. Competitive Oxidation and Reduction of Aliphatic Alcohols over (WO3)3 Clusters

    SciTech Connect

    Kim, Yu K.; Dohnalek, Zdenek; Kay, Bruce D.; Rousseau, Roger J.

    2009-06-04

    The reactions of C1 to C4 aliphatic alcohols over (WO3)3 clusters were studied experimentally and theoretically using temperature-programmed desorption, infrared reflection-absorption spectroscopy and density functional theory. The results reveal that all C1 to C4 aliphatic alcohols readily react with (WO3)3 clusters by heterolytic cleavage of the RO-H bond to give alkoxy (RO ) bound to W(VI) centers and a proton (H+) attached to the terminal oxygen atom of a tungstyl group (W=O). Two protons adsorbed onto the cluster readily react with the doubly-bonded oxygen to from a water molecule that desorbs at 200-300 K and the alkoxy that undergoes decomposition at higher temperatures into the corresponding alkene, aldehyde, and/or ether. Our theory predicts that all three channels proceed over the W(VI) Lewis acid site with energy barriers of 30-40 kcal/mol, where dehydration is favored over the others. We also present further analysis of the yield and reaction temperature as a function of the alkyl substituents and discuss the origin of the reaction selectivity among the three reaction channels.

  12. Poly[bis­(N,N-dimethyl­formamide)tris­(μ4-trans-stilbene-4,4′-dicarboxyl­ato)­tricadmium(II)]: a two-dimensional network with an unusual 36 topology

    PubMed Central

    Lee, Dong-Heon; Park, Gyungse

    2008-01-01

    In the title compound, [Cd3(C16H10O4)3(C3H7NO)2]n or [Cd3(SDA)3(DMF)2]n (H2SDA is trans-stilbene-4,4′-dicarboxylic acid and DMF is dimethyl­formamide), the linear dicarboxylate ligand forms a two-dimensionally layered metal–organic network with the relatively uncommon 36 topology. The structure reveals trinuclear secondary building units and has an octa­hedral geometry at a central metal ion (occupying a symmetry site) and tetra­hedral geometries at two surrounding symmetrically equivalent metal ions lying on a threefold axis. The six-connected planar trinuclear CdII centers, Cd3(O2CR)6, play a role as potential nodes in generation of the relatively uncommon 36 topology. The coordinated DMF unit is disordered around the threefold axis. PMID:21202737

  13. Syntheses, structures and properties of three metal–organic complexes containing 2,2′-dipyridyl-5,5′-dicarboxylate ligands

    SciTech Connect

    Liu, Jiancai; Zhang, Yudong; Shang, Sensen; Li, Yanzhou; Chen, Lijuan Zhao, Junwei

    2015-01-15

    Three new metal–organic complexes Cu[Hbpdc]{sub 2} (1), [Ni(bpdc)(H{sub 2}O)]·H{sub 2}O (2) and [Ni(H{sub 2}bpdc)(H{sub 2}O){sub 2}]SO{sub 4} (3) (H{sub 2}bpdc=2,2′-bipyridyl-5,5′-dicarboxylic acid) have been hydrothermally prepared and structurally characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. 1 is a 3-D supramolecular architecture formed by hydrogen bonding interactions between carboxyl O atoms and strong face-to-face π⋯π stacking interactions between bipyridyl rings of Hbpdc{sup −} ligands, 2 exhibits an intriguing 2-D sheet constructed from [Ni(bpdc)(H{sub 2}O)] units and 3 displays an infinite 1-D chain built by ([Ni(H{sub 2}bpdc)(H{sub 2}O){sub 2}]{sup 2+}) fragments through SO{sub 4}{sup 2−}. Moreover, thermogravimetric (TG) and derivative thermogravimetric (DTG) analyses of 3 have been conducted and the TG curve shows two-stage weight loss between 300 and 950 K and the corresponding apparent activation energies are calculated by Ozawa–Flynn–Wall (OFW) method and Friedman method. The most probable kinetic model function of the dehydration reaction of 3 has been estimated by Coats–Redfern integral method and Achar–Bridly–Sharp differential method. - Graphical abstract: Three metal–organic complexes containing 2,2′-dipyridyl-5,5′-dicarboxylate ligands were synthesized and the thermal decomposition kinetics were investigated. - Highlights: • Metal–organic complexes containing 2,2′-dipyridyl-5,5′-dicarboxylate ligands. • 3-D supramolecular architecture. • Thermal decomposition kinetics.

  14. Lipstick dermatitis due to C18 aliphatic compounds.

    PubMed

    Hayakawa, R; Matsunaga, K; Suzuki, M; Arima, Y; Ohkido, Y

    1987-04-01

    An 18-year-old girl developed cheilitis. She had a past history of lip cream dermatitis, but the cause was not found. Patch tests with 2 lipsticks were strongly positive. Tests with the ingredients were positive to 2 aliphatic compounds, glyceryl diisostearate and diisostearyl malate. Impurities in the materials were suspected as the cause. Analysis by gas chromatography detected 3 chemicals in glyceryl diisostearate and 1 in diisostearyl malate as impurities. Patch testing with the impurities and glyceryl monoisostearate 0.01% pet in glyceryl diisostearate and isostearyl alcohol 0.25% pet in diisostearyl malate were strongly positive. The characteristics common to the 2 chemicals were liquidity at room temperature, branched C18 aliphatic compound and primary alcohol. Chemicals lacking any of the above 3 features did not react.

  15. Determination of aliphatic hydrocarbons in the alga Himanthalia elongata.

    PubMed

    Punín Crespo, M O; Lage Yusty, M A

    2004-02-01

    The algae considered new foods according to Regulation CE 258/97 need a guarantee of their healthfulness before being in the European market. In this work ten samples of the brown alga Himanthalia elongata have been analyzed with the aim of verifying the absence of aliphatic hydrocarbons, due to the ability of the macroalgae to capture lipophilic organic compounds of the marine water coming from accidental or continuous leaks of raw oil and refined products, which happen each year with the growth of the industrialization and the demand of energy. The fat of the samples were Soxhlet extracted using hexane:dichloromethane (1:1) for 7h. The organic fractions were purified using silica microcolumns. The identification and quantification of the aliphatic hydrocarbons have been carried out using gas chromatography (GC) with flame ionization detector (FID). The total hydrocarbon content was between 14.8 and 40.2 microg g(-1) dry weight. PMID:14759670

  16. Biodegradation of Trihalomethanes and Other Halogenated Aliphatic Compounds

    NASA Technical Reports Server (NTRS)

    Smith, G. B.

    1996-01-01

    The biological dehalogenation of common water pollutants such as trichloromethane (chloroform) and other halogenated aliphatic compounds was the subject of this project. Samples from diverse water environments such as from groundwater contaminated with halogenated compounds and wastewaters from regional treatment plants were studied to identify conditions that favor certain dehalogenation reactions over others. Gene probe analyses of DNA extracted from the dichlormethane-degrading wastewater indicated the presence of the gene coding for dichloromethane dehalogenase, indicating the genetic basis for the dechlorination activity observed. These studies indicate that methanogenic bacteria are the organisms responsible for the chloroform dechlorination. Dechlorination of a common chlorofluorocarbon (CFC-11) was identified in samples taken from a regional aquifer contaminated with halogenated aliphatic compounds.

  17. Aliphatics hydrocarbon content in surface sediment from Jakarta Bay, Indonesia

    NASA Astrophysics Data System (ADS)

    YAzis, M.; Asia, L.; Piram, A.; Doumenq, P.; Syakti, A. D.

    2016-02-01

    Sedimentary aliphatic hydrocarbons content have been studied quantitatively and qualitatively using GC/MS method in eight coastal stations located in the Jakarta Bay, North of Jakarta, Indonesia. The total concentrations n-alkanes have ranged from 480 μg.kg-1to 1,935 μg.kg-1sediment dry weight. Several ratios (e.g. CPI24-32, NAR, TAR, Pr/Phy, n-C17/Pr, n- C18/Phyt,n-C29/n-C17, Ʃn-alkanes/n-C16LMW/HMW, Paq and TMD) were used to evaluate the possible sources of terrestrial-marine inputs of these hydrocarbons in the sediments. The various origins of aliphatic hydrocarbons were generally biogenic, including both terrigenous and marine, with an anthropogenic pyrolytic contribution (petrogenic and biogenic combustion). Two stations (G,H) were thehighest concentration and had potential risk to environment

  18. Manganese-Mediated Coupling Reaction of Vinylarenes and Aliphatic Alcohols

    PubMed Central

    Zhang, Wei; Wang, Nai-Xing; Bai, Cui-Bing; Wang, Yan-Jing; Lan, Xing-Wang; Xing, Yalan; Li, Yi-He; Wen, Jia-Long

    2015-01-01

    Alcohols and alkenes are the most abundant and commonly used organic building blocks in the large-scale chemical synthesis. Herein, this is the first time to report a novel and operationally simple coupling reaction of vinylarenes and aliphatic alcohols catalyzed by manganese in the presence of TBHP (tert-butyl hydroperoxide). This coupling reaction provides the oxyalkylated products of vinylarenes with good regioselectivity and accomplishes with the principles of step-economies. A possible reaction mechanism has also been proposed. PMID:26470633

  19. Room Temperature, Metal-Free Arylation of Aliphatic Alcohols

    PubMed Central

    Ghosh, Raju; Lindstedt, Erik; Jalalian, Nazli; Olofsson, Berit

    2014-01-01

    Diaryliodonium salts are demonstrated as efficient arylating agents of aliphatic alcohols under metal-free conditions. The reaction proceeds at room temperature within 90 min to give alkyl aryl ethers in good to excellent yields. Aryl groups with electron-withdrawing substituents are transferred most efficiently, and unsymmetric iodonium salts give chemoselective arylations. The methodology has been applied to the formal synthesis of butoxycaine. PMID:24808991

  20. Aerobic microorganism for the degradation of chlorinated aliphatic hydrocarbons

    DOEpatents

    Fliermans, Carl B.

    1989-01-01

    A chlorinated aliphatic hydrocarbon-degrading microorganism, having American Type Culture Collection accession numbers ATCC 53570 and 53571, in a biologically pure culture aseptically collected from a deep subsurface habitat and enhanced, mineralizes trichloroethylene and tetrachloroethylene to HCl, H.sub.2 O and Co.sub.2 under aerobic conditions stimulated by methane, acetate, methanol, tryptone-yeast extract, propane and propane-methane.

  1. Manganese-Mediated Coupling Reaction of Vinylarenes and Aliphatic Alcohols.

    PubMed

    Zhang, Wei; Wang, Nai-Xing; Bai, Cui-Bing; Wang, Yan-Jing; Lan, Xing-Wang; Xing, Yalan; Li, Yi-He; Wen, Jia-Long

    2015-01-01

    Alcohols and alkenes are the most abundant and commonly used organic building blocks in the large-scale chemical synthesis. Herein, this is the first time to report a novel and operationally simple coupling reaction of vinylarenes and aliphatic alcohols catalyzed by manganese in the presence of TBHP (tert-butyl hydroperoxide). This coupling reaction provides the oxyalkylated products of vinylarenes with good regioselectivity and accomplishes with the principles of step-economies. A possible reaction mechanism has also been proposed. PMID:26470633

  2. Manganese-Mediated Coupling Reaction of Vinylarenes and Aliphatic Alcohols

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Wang, Nai-Xing; Bai, Cui-Bing; Wang, Yan-Jing; Lan, Xing-Wang; Xing, Yalan; Li, Yi-He; Wen, Jia-Long

    2015-10-01

    Alcohols and alkenes are the most abundant and commonly used organic building blocks in the large-scale chemical synthesis. Herein, this is the first time to report a novel and operationally simple coupling reaction of vinylarenes and aliphatic alcohols catalyzed by manganese in the presence of TBHP (tert-butyl hydroperoxide). This coupling reaction provides the oxyalkylated products of vinylarenes with good regioselectivity and accomplishes with the principles of step-economies. A possible reaction mechanism has also been proposed.

  3. Formation and Morphology of "shish-like" Fibril Crystals of Aliphatic Polyesters from the Sheared Melt

    SciTech Connect

    Yamazaki, S.; Itoh, M; Oka, T; Kimura, K

    2010-01-01

    We found the formation of 'shish-like' fibril crystals of aliphatic polyesters such as poly(L-lactic acid) (PLLA), poly({var_epsilon}-caprolactone) (PCL), poly(12-hydroxydodecanoic acid) (PHDA) and poly(16-hydroxyhexadecanoic acid) (PHHA) from the sheared melt with shear rate {gamma} = 5 s{sup -1} observed by polarizing optical microscope (POM). The melting temperature T{sub m}s of obtained fibril crystals of PLLA and PCL were higher than those of spherulites and were close to the equilibrium melting temperature T{sub m}{sup 0}. The small angle X-ray scattering (SAXS) patterns from the bulk sample including fibril crystals, small amount of unoriented small crystals and amorphous showed no peaks arose from the existence of long periods in fibril crystals. These are the evidence that the observed fibril crystals consist of assemblies of a lot of extended chain crystals (ECCs). We observed the morphology of moderately extracted single strand of fibril crystals at the magnification of POM by means of scanning electron microscope. We found that macroscopic fibril crystals of PLLA with diameter d = 10 {micro}m consist of the bundle structure of microscopic fibril crystals with d = 2 {micro}m. From POM observation of the formation of fibril crystals of PLLA and PCL, we showed phase diagrams of molecular weight M and crystallization temperature T{sub c} for the formation of fibril crystals. From these phase diagrams, we evaluated a critical M and T{sub c} for the formation of fibril crystals. Moreover, from the sequential melting and crystallization experiments, it was implied that the entanglement and transesterification play an important role on the formation of fibril crystals of aliphatic polyesters.

  4. Biodegradation of aliphatic vs. aromatic hydrocarbons in fertilized arctic soils

    USGS Publications Warehouse

    Braddock, J.F.

    1999-01-01

    A study was carried out to test a simple bioremediation treatment strategy in the Arctic and analyze the influence of fertilization the degradation of aliphatic and aromatic hydrocarbons, e.g., pristine, n-tetradecane, n-pentadecane, 2-methylnaphthalene, naphthalene, and acenaphthalene. The site was a coarse sand pad that once supported fuel storage tanks. Diesel-range organics concentrations were 250-860 mg/kg soil at the beginning of the study. Replicate field plots treated with fertilizer yielded final concentrations of 0, 50, 100, or 200 mg N/kg soil. Soil pH and soil-water potentials decreased due to fertilizer application. The addition of fertilizer considerably increased soil respiration potentials, but not the populations of microorganisms measured. Fertilizer addition also led to ??? 50% loss of measured aliphatic and aromatic hydrocarbons in surface and subsurface soils. For fertilized plots, hydrocarbon loss was not associated with the quantity of fertilizer added. Losses of aliphatic hydrocarbons were ascribed to biotic processes, while losses of aromatic hydrocarbons were due to biotic and abiotic processes.

  5. Ligand-controlled assembly of Cd(II) coordination polymers based on mixed ligands of naphthalene-dicarboxylate and dipyrido[3,2-d:2‧,3‧-f]quinoxaline: From 0D+1D cocrystal, 2D rectangular network (4,4), to 3D PtS-type architecture

    NASA Astrophysics Data System (ADS)

    Liu, Guocheng; Chen, Yongqiang; Wang, Xiuli; Chen, Baokuan; Lin, Hongyan

    2009-03-01

    Three novel Cd(II) coordination polymers, namely, [Cd(Dpq)(1,8-NDC)(H 2O) 2][Cd(Dpq)(1,8-NDC)]·2H 2O ( 1), [Cd(Dpq)(1,4-NDC)(H 2O)] ( 2), and [Cd(Dpq)(2,6-NDC)] ( 3) have been obtained from hydrothermal reactions of cadmium(II) nitrate with the mixed ligands dipyrido [3,2-d:2',3'-f]quinoxaline (Dpq) and three structurally related naphthalene-dicarboxylate ligands [1,8-naphthalene-dicarboxylic acid (1,8-H 2NDC), 1,4-naphthalene-dicarboxylic acid (1,4-H 2NDC), and 2,6-naphthalene-dicarboxylic acid (2,6-H 2NDC)]. Single-crystal X-ray diffraction analysis reveals that the three polymers exhibit novel structures due to different naphthalene-dicarboxylic acid. Compound 1 is a novel cocrystal of left- and right-handed helical chains and binuclear complexes and ultimately packed into a 3D supramolecular structure through hydrogen bonds and π- π stacking interactions. Compound 2 shows a 2D rectangular network (4,4) bridged by 1,4-NDC with two kinds of coordination modes and ultimately packed into a 3D supramolecular structure through inter-layer π- π stacking interactions. Compound 3 is a new 3D coordination polymer with distorted PtS-type network. In addition, the title compounds exhibit blue/green emission in solid state at room temperature.

  6. 76 FR 76963 - Certain New Chemicals; Receipt and Status Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-09

    ...) Hydroxyl-terminated aliphatic polycarbonate. P-10-0111 10/24/2011 10/6/2011 (G) Benzene dicarboxylic acid...; aliphatic polycarbonate. P-10-0286 10/20/2011 9/28/2011 (G) Hydroxyl-terminated aliphatic polycarbonate. P-10-0287 10/20/2011 9/26/2011 (G) Hydroxyl-terminated aliphatic polycarbonate. P-10-0288 10/20/2011...

  7. Aerobic growth of campylobacter in media supplemented with C3-monocarboxylates and C4-dicarboxylates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted to examine aerobic growth of Campylobacter spp. in media supplemented with C4-dicarboxylates (fumarate, succinate, or malate) and C3-monocarboxylates (pyruvate or lactate). Basal broth media composed of tryptose, yeast extract, and a mineral-vitamin solution was supplement...

  8. Cyclization-induced turn-on fluorescence system applicable to dicarboxylate sensing.

    PubMed

    Noguchi, Takao; Roy, Bappaditya; Yoshihara, Daisuke; Tsuchiya, Youichi; Yamamoto, Tatsuhiro; Shinkai, Seiji

    2014-01-01

    A novel tetraphenylethene-based fluorescence (FL) chemosensor exhibits nonlinear turn-on FL switching though cooperative binding of L-tartarate, where its convergent binding to form cyclic substructures is responsible for the FL increase. This binding scheme achieves selective detection of dicarboxylates over monocarboxylates, thus is potentially applicable to the preliminary screening for metabolic disorders.

  9. Biochemical Characterization of the C4-Dicarboxylate Transporter DctA from Bacillus subtilis▿

    PubMed Central

    Groeneveld, Maarten; Detert Oude Weme, Ruud G. J.; Duurkens, Ria H.; Slotboom, Dirk Jan

    2010-01-01

    Bacterial secondary transporters of the DctA family mediate ion-coupled uptake of C4-dicarboxylates. Here, we have expressed the DctA homologue from Bacillus subtilis in the Gram-positive bacterium Lactococcus lactis. Transport of dicarboxylates in vitro in isolated membrane vesicles was assayed. We determined the substrate specificity, the type of cotransported ions, the electrogenic nature of transport, and the pH and temperature dependence patterns. DctA was found to catalyze proton-coupled symport of the four C4-dicarboxylates from the Krebs cycle (succinate, fumurate, malate, and oxaloacetate) but not of other mono- and dicarboxylates. Because (i) succinate-proton symport was electrogenic (stimulated by an internal negative membrane potential) and (ii) the divalent anionic form of succinate was recognized by DctA, at least three protons must be cotransported with succinate. The results were interpreted in the light of the crystal structure of the homologous aspartate transporter GltPh from Pyrococcus horikoshii. PMID:20363944

  10. Segregation and Alteration of Phenolic and Aliphatic Components of Root and Leaf Litter by Detritivores and Microbes

    NASA Astrophysics Data System (ADS)

    Filley, T. R.; Altmann, J.; Szlavecz, K. A.; Kalbitz, K.; Gamblin, D.; Nierop, K.

    2012-12-01

    The physical and microbial transformation of plant detritus in the litter layer and soil is accompanied by chemical separation of progressively soluble fractions and their movement into the rhizosphere driving subsequent soil processes. We investigated the combined action of specific detritivores, microbial decay, and leaching on the chemical separation of plant aromatic and aliphatic components from root, wood, and leaf tissue using 13C-TMAH thermochemolysis. This method enabled the simultaneous analysis of hydrolyzable tannin and lignin fragments, substituted fatty acids, and condensed tannin composition and revealed process-specific chemical transformations to plant secondary compounds. Long-term incubation and field sampling demonstrated how plant residues are progressively leached of the water soluble, oxidized fragments generated through decay. The residues appeared only slightly altered, in the case of brown rot wood, or enriched in aliphatic fragments, in the case of leaf and root tissue. Water extractable fractions were always selectively dominated by polyphenolics, either as demethylated lignin or tannins, and nearly devoid of aliphatic materials, despite high concentrations in the starting materials. Additionally, for plant materials with high tannin contents, such as pine needles, consumption and passage through some arthropod guts revealed what appeared to be microbially-mediated methylation of phenols, and a loss of tannins in leachates. These findings are indications for an in-situ phenol detoxification mechanism. This research provides important information regarding the links between biochemical decay and the chemical nature of organic matter removed and remaining in the soil profile.

  11. Thermally induced degradation of sulfur-containing aliphatic glucosinolates in broccoli sprouts (Brassica oleracea var. italica) and model systems.

    PubMed

    Hanschen, Franziska S; Platz, Stefanie; Mewis, Inga; Schreiner, Monika; Rohn, Sascha; Kroh, Lothar W

    2012-03-01

    Processing reduces the glucosinolate (GSL) content of plant food, among other aspects due to thermally induced degradation. Since there is little information about the thermal stability of GSL and formation of corresponding breakdown products, the thermally induced degradation of sulfur-containing aliphatic GSL was studied in broccoli sprouts and with isolated GSL in dry medium at different temperatures as well as in aqueous medium at different pH values. Desulfo-GSL have been analyzed with HPLC-DAD, while breakdown products were estimated using GC-FID. Whereas in the broccoli sprouts structural differences of the GSL with regard to thermal stability exist, the various isolated sulfur-containing aliphatic GSL degraded nearly equally and were in general more stable. In broccoli sprouts, methylsulfanylalkyl GSL were more susceptible to degradation at high temperatures, whereas methylsulfinylalkyl GSL were revealed to be more affected in aqueous medium under alkaline conditions. Besides small amounts of isothiocyanates, the main thermally induced breakdown products of sulfur-containing aliphatic GSL were nitriles. Although they were most rapidly formed at comparatively high temperatures under dry heat conditions, their highest concentrations were found after cooking in acidic medium, conditions being typical for domestic processing.

  12. Cost-Benefit Analysis for Alternatives to Aliphatic Isocyanate Polyurethanes

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie

    2007-01-01

    NASA and Air Force Space Command (AFSPC) have similar missions and therefore similar facilities and structures in similar environments. The standard practice for protecting metallic substrates in atmospheric environments is the application of an applied coating system. The most common topcoats used in coating systems are polyurethanes that contain isocyanates. Isocyanates are classified as potential human carcinogens and are known to cause cancer in animals. The primary objective of this effort was to demonstrate and validate alternatives to aliphatic isocyanate polyurethanes resulting in one or more isocyanate-free coatings qualified for use at AFSPC and NASA installations participating in this project. This Cost-Benefit Analysis (CBA) quantifies the estimated capital and process costs of coating alternatives and cost savings relative to the current coatings. The estimates in this CBA are to be used for assessing the relative merits of the selected alternatives. The actual economic effects at any specific facility will depend on the alternative material or technology implemented, the number of actual applications converted, future workloads, and other factors . The participants initially considered eighteen (18) alternative coatings as described in the Potential Alternatives Report entitled Potential Alternatives Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, prepared by ITB. Of those, 8 alternatives were selected for testing in accordance with the Joint Test Protocol entitled Joint Test Protocol for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, and the Field Test Plan entitled Field Evaluations Test Plan for Validation of Alternatives 10 Aliphatic Isocyanate Polyurethanes, both of which were prepared by ITB. A joint Test Report entitled Joint Test Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, prepared by ITB, documents the results of the laboratory and field testing, as well as any

  13. A rapid and sensitive method for the simultaneous analysis of aliphatic and polar molecules containing free carboxyl groups in plant extracts by LC-MS/MS

    PubMed Central

    2009-01-01

    Background Aliphatic molecules containing free carboxyl groups are important intermediates in many metabolic and signalling reactions, however, they accumulate to low levels in tissues and are not efficiently ionized by electrospray ionization (ESI) compared to more polar substances. Quantification of aliphatic molecules becomes therefore difficult when small amounts of tissue are available for analysis. Traditional methods for analysis of these molecules require purification or enrichment steps, which are onerous when multiple samples need to be analyzed. In contrast to aliphatic molecules, more polar substances containing free carboxyl groups such as some phytohormones are efficiently ionized by ESI and suitable for analysis by LC-MS/MS. Thus, the development of a method with which aliphatic and polar molecules -which their unmodified forms differ dramatically in their efficiencies of ionization by ESI- can be simultaneously detected with similar sensitivities would substantially simplify the analysis of complex biological matrices. Results A simple, rapid, specific and sensitive method for the simultaneous detection and quantification of free aliphatic molecules (e.g., free fatty acids (FFA)) and small polar molecules (e.g., jasmonic acid (JA), salicylic acid (SA)) containing free carboxyl groups by direct derivatization of leaf extracts with Picolinyl reagent followed by LC-MS/MS analysis is presented. The presence of the N atom in the esterified pyridine moiety allowed the efficient ionization of 25 compounds tested irrespective of their chemical structure. The method was validated by comparing the results obtained after analysis of Nicotiana attenuata leaf material with previously described analytical methods. Conclusion The method presented was used to detect 16 compounds in leaf extracts of N. attenuata plants. Importantly, the method can be adapted based on the specific analytes of interest with the only consideration that the molecules must contain at

  14. Novel aliphatic lipid-based diesters for use in lubricant formulations: Structure property investigations

    NASA Astrophysics Data System (ADS)

    Raghunanan, Latchmi Cindy

    Structure-property relationships are increasingly valued for the identification of specifically engineered materials with properties optimized for targeted application(s). In this work, linear and branched diesters for use in lubricant formulations are prepared from lipid-based oleochemicals and their structure-property relationships reported. It is shown that the branched diesters possess exceptional physical property profiles, including suppression of crystallization, and are superior alternatives for use in lubricant formulations. For the linear aliphatic diesters, both high and low temperature properties were predictable functions of total chain length, and both were differently influenced by the fatty acid versus diol chain length. Symmetry did not influence either, although thermal stability decreased and thermal transition temperatures increased with increasing saturation. All of the linear diesters demonstrated Newtonian flow behaviour. Viscosity was also predictable as a function of total chain length; any microstructural features due to structural effects were superseded by mass effects.

  15. Platinum-Catalyzed, Terminal-Selective C(sp(3))-H Oxidation of Aliphatic Amines.

    PubMed

    Lee, Melissa; Sanford, Melanie S

    2015-10-14

    This Communication describes the terminal-selective, Pt-catalyzed C(sp(3))-H oxidation of aliphatic amines without the requirement for directing groups. CuCl2 is employed as a stoichiometric oxidant, and the reactions proceed in high yield at Pt loadings as low as 1 mol%. These transformations are conducted in the presence of sulfuric acid, which reacts with the amine substrates in situ to form ammonium salts. We propose that protonation of the amine serves at least three important roles: (i) it renders the substrates soluble in the aqueous reaction medium; (ii) it limits binding of the amine nitrogen to Pt or Cu; and (iii) it electronically deactivates the C-H bonds proximal to the nitrogen center. We demonstrate that this strategy is effective for the terminal-selective C(sp(3))-H oxidation of a variety of primary, secondary, and tertiary amines. PMID:26439251

  16. Coligand-regulated assembly, fluorescence, and magnetic properties of Co(II) and Cd(II) complexes with a non-coplanar dicarboxylate

    NASA Astrophysics Data System (ADS)

    Xin, Ling-Yun; Liu, Guang-Zhen; Ma, Lu-Fang; Wang, Li-Ya

    2013-10-01

    A non-coplanar dicarboxylate ndca (H2ndca=5-norbornene-2,3-dicarboxylic acid), combining with various dipyridyl-typed tectons, constructs six Cd(II)/Co(II) coordination polymers under hydrothermal conditions, namely [Co(ndca)(H2O)]n (1), {[Co(ndca)(bpe)(H2O)]·H2O}n (2), [Co(ndca)(bpa)0.5(H2O)]n (3), [Cd(ndca)(bpe)(H2O)]n (4), {[Cd(ndca)(bpa)(H2O)]·0.5H2O}n (5), and {[Cd(ndca)(bpp) (H2O)]·H2O}n (6) (bpe=1,2-di(4-pyridyl)ethylene, bpa=1,2-bi(4-pyridyl)ethane, and bpp=1,3-bis(4-pyridyl)propane). All these compounds contain various metal(II)-carboxylate motifs, including carboxylate binuclear (2, 4, 5), carboxylate chain (1, 6) and carboxylate layer (3), which are further extended by dipyridyl-typed coligands to afford a vast diversity of the structures with 2D pyknotic layers (1, 6), 2D open layer (5), 2D→3D interpenetrated networks (2,4), and 3D pillared-layer framework (3), respectively. In addition, fluorescent spectra of Cd(II) complexes and magnetic properties of Co(II) complexes are also given.

  17. Complexation of NpO2+ with N-methyl-iminodiacetic Acid: in Comparison with Iminodiacetic and Dipicolinic Acids

    SciTech Connect

    Tian, Guoxin; Rao, Linfeng

    2010-10-01

    Complexation of Np(V) with N-methyl-iminodiacetic acid (MIDA) in 1 M NaClO{sub 4} solution was studied with multiple techniques including potentiometry, spectrophotometry, and microcalorimetry. The 1:2 complex, NpO{sub 2}(MIDA){sub 2}{sup 3-} was identified for the first time in aqueous solution. The correlation between its optical absorption properties and symmetry was discussed, in comparison with Np(V) complexes with two structurally related nitrilo-dicarboxylic acids, iminodiacetic acid (IDA) and dipicolinic acid (DPA). The order of the binding strength (DPA > MIDA > IDA) is explained by the difference in the structural and electronic properties of the ligands. In general, the nitrilo-dicarboxylates form stronger complexes with Np(V) than oxy-dicarboxylates due to a much more favorable enthalpy of complexation.

  18. Assessing the Origins of Aliphatic Amines in the Murchison Meteorite from their Compound-Specific Carbon Isotopic Ratios and Enantiomeric Composition

    NASA Technical Reports Server (NTRS)

    Aponte, Jose; Dworkin, Jason; Elsila, Jamie E.

    2014-01-01

    The study of meteoritic organic compounds provides a unique window into the chemical inventory of the early Solar System and prebiotic chemistry that may have been important for the origin of life on Earth. Multiple families of organic compounds have been extracted from the Murchison meteorite, which is one of the most thoroughly studied carbonaceous chondrites. The amino acids extracted from Murchison have been extensively analyzed, including measurements of non-terrestrial stable isotopic ratios and discoveries of L-enantiomeric excesses for alpha-dialkyl amino acids, notably isovaline. However, although the isotopic signatures of bulk amine-containing fractions have been measured, the isotopic ratios and enantiomeric composition of individual aliphatic amines, compounds that are chemically related to amino acids, remain unknown. Here, we report a novel method for the extraction, separation, identification and quantitation of aliphatic monoamines extracted from the Murchison meteorite. Our results show a complete suite of structural isomers, with a larger concentration of methylamine and ethylamine and decreasing amine concentrations with increasing carbon number. The carbon isotopic compositions of fourteen meteoritic aliphatic monoamines were measured, with delta C-13 values ranging from +21% to +129%, showing a decrease in C-13 with increasing carbon number, a relationship that may be consistent with the chain elongation mechanism under kinetic control previously proposed for meteoritic amino acids. We also found the enantiomeric composition of sec-butylamine, a structural analog to isovaline, was racemic within error, while the isovaline extracted from the same Murchison piece showed an L-enantiomeric excess of 9.7; this result suggested that processes leading to enantiomeric excess in the amino acid did not affect the amine. We used these collective data to assess the primordial synthetic origins of these meteoritic aliphatic amines and their potential

  19. Assessing the origins of aliphatic amines in the Murchison meteorite from their compound-specific carbon isotopic ratios and enantiomeric composition

    NASA Astrophysics Data System (ADS)

    Aponte, José C.; Dworkin, Jason P.; Elsila, Jamie E.

    2014-09-01

    The study of meteoritic organic compounds provides a unique window into the chemical inventory of the early Solar System and prebiotic chemistry that may have been important for the origin of life on Earth. Multiple families of organic compounds have been extracted from the Murchison meteorite, which is one of the most thoroughly studied carbonaceous chondrites. The amino acids extracted from Murchison have been extensively analyzed, including measurements of non-terrestrial stable isotopic ratios and discoveries of L-enantiomeric excesses for α-dialkyl amino acids, notably isovaline. However, although the isotopic signatures of bulk amine-containing fractions have been measured, the isotopic ratios and enantiomeric composition of individual aliphatic amines, compounds that are structurally related to amino acids, remain unknown. Here, we report a novel method for the extraction, separation, identification and quantitation of aliphatic monoamines extracted from the Murchison meteorite. Our results show a complete suite of structural isomers, with a larger concentration of methylamine and ethylamine and decreasing amine concentrations with increasing carbon number. The carbon isotopic compositions of fourteen meteoritic aliphatic monoamines were measured, with δ13C values ranging from +21‰ to +129‰, showing a decrease in 13C with increasing carbon number, a relationship that may be consistent with the chain elongation mechanism under kinetic control previously proposed for meteoritic amino acids. We also found the enantiomeric composition of sec-butylamine, a structural analog to isovaline, was racemic within error, while the isovaline extracted from the same Murchison piece showed an L-enantiomeric excess of 9.7%; this result suggested that processes leading to enantiomeric excess in the amino acid did not affect the amine. We used these collective data to assess the primordial synthetic origins of these meteoritic aliphatic amines and their potential linkage

  20. Amino and fatty acids in carbonaceous meteorites

    NASA Technical Reports Server (NTRS)

    Kvenvolden, K. A.

    1974-01-01

    Analyses of two carbonaceous meteorites have provided much of the latest evidence which seems to support Oparin's theory on the origin of life. The meteorites involved are the Murray meteorite, which fell in 1950, and the Murchison meteorite, which fell in 1969. The amino acids in the two meteorites are similar in composition. Eight of the twenty amino acids found belong to amino acids present in proteins. A number of monocarboxylic and dicarboxylic fatty acids were also found in the meteorites.

  1. Aliphatic peptidyl hydroperoxides as a source of secondary oxidation in hydroxyl radical protein footprinting

    PubMed Central

    Saladino, Jessica; Liu, Mian; Live, David; Sharp, Joshua S.

    2009-01-01

    Hydroxyl radical footprinting is a technique for studying protein structure and binding that entails oxidizing a protein system of interest with diffusing hydroxyl radicals, and then measuring the amount of oxidation of each amino acid. One important issue in hydroxyl radical footprinting is limiting amino acid oxidation by secondary oxidants to prevent uncontrolled oxidation which can cause amino acids to appear more solvent accessible than they really are. Previous work suggested that hydrogen peroxide was the major secondary oxidant of concern in hydroxyl radical footprinting experiments; however, even after elimination of all hydrogen peroxide, some secondary oxidation was still detected. Evidence is presented for the formation of peptidyl hydroperoxides as the most abundant product upon oxidation of aliphatic amino acids. Both reverse phase liquid chromatography and catalase treatment were shown to be ineffective at eliminating peptidyl hydroperoxides. The ability of these peptidyl hydroperoxides to directly oxidize methionine is demonstrated, suggesting the value of methionine amide as an in situ protectant. Hydroxyl radical footprinting protocols require the use of an organic sulfide or similar peroxide scavenger in addition to removal of hydrogen peroxide in order to successfully eradicate all secondary oxidizing species and prevent uncontrolled oxidation of sulfur-containing residues. PMID:19278868

  2. A convenient tandem one-pot synthesis of donor-acceptor-type triphenylene 2,3-dicarboxylic esters from diarylacetylene.

    PubMed

    Feng, Chun; Tian, Xian-Li; Zhou, Jing; Xiang, Shi-Kai; Yu, Wen-Hao; Wang, Bi-Qin; Hu, Ping; Redshaw, Carl; Zhao, Ke-Qing

    2014-09-28

    A tandem one-pot method for the direct synthesis of polysubstituted triphenylene 2,3-dicarboxylic esters with different substitution patterns was developed by enyne metathesis of diarylacetylene, followed by Diels-Alder, aromatization and a cyclization cascade.

  3. Aliphatic polyesters: great degradable polymers that cannot do everything.

    PubMed

    Vert, Michel

    2005-01-01

    Nowadays the open and the patent literatures propose a large number of polymers whose main chains can be degraded usefully. Among these degradable polymers, aliphatic polyester-based polymeric structures are receiving special attention because they are all more or less sensitive to hydrolytic degradation, a feature of interest when compared with the fact that living systems function in aqueous media. Only some of these aliphatic polyesters are enzymatically degradable. A smaller number is biodegradable, and an even more limited number is biorecyclable. To be of practical interest, a degradable polymer must fulfill many requirements that depend very much on the targeted application, on the considered living system, and on living conditions. It is shown that aliphatic polyester structures made of repeating units that can generate metabolites upon degradation or biodegradation like poly(beta-hydroxy alkanoate)s and poly(alpha-hydroxy alkanoate)s are of special interest. Their main characteristics are confronted to the specifications required by various potential sectors of applications, namely, surgery, pharmacology, and the environment. It is shown that degradation, bioresorption, and biorecycling that are targets when one wants to respect living systems are also drastic limiting factors when one wants to achieve a device of practical interest. Finding a universal polymer that would be the source of all the polymeric biomaterials needed to work in contact with living organisms of the various life kingdoms and respect them remains a dream. On the other hand, finding one polymeric structure than can fulfill the requirements of one niche application remains a big issue.

  4. Aliphatic Polyethers: Classical Polymers for the 21st Century.

    PubMed

    Klein, Rebecca; Wurm, Frederik R

    2015-06-01

    Polyethers-polymers with the structural element (R'-O-R)n in their backbone--are an old class of polymers which were already used at the time of the ancient Egyptians. However, still today these materials are highly important with applications in all areas of our life, reaching from the automotive and paper industry to cosmetics and biomedical applications. In this Review, different aliphatic polyethers like poly(epoxide)s, poly(oxetane)s, and poly(tetrahydrofuran) are discussed. Special emphasis is placed on the history, the polymerization techniques (industrially and in academia), the properties, the applications as well as recent developments of these materials.

  5. Manganese-catalyzed selective oxidation of aliphatic C-H groups and secondary alcohols to ketones with hydrogen peroxide.

    PubMed

    Dong, Jia Jia; Unjaroen, Duenpen; Mecozzi, Francesco; Harvey, Emma C; Saisaha, Pattama; Pijper, Dirk; de Boer, Johannes W; Alsters, Paul; Feringa, Ben L; Browne, Wesley R

    2013-09-01

    An efficient and simple method for selective oxidation of secondary alcohols and oxidation of alkanes to ketones is reported. An in situ prepared catalyst is employed based on manganese(II) salts, pyridine-2-carboxylic acid, and butanedione, which provides good-to-excellent conversions and yields with high turnover numbers (up to 10 000) with H2 O2 as oxidant at ambient temperatures. In substrates bearing multiple alcohol groups, secondary alcohols are converted to ketones selectively and, in general, benzyl C-H oxidation proceeds in preference to aliphatic C-H oxidation.

  6. Palladium-catalyzed hydroaminocarbonylation of alkenes with amines: a strategy to overcome the basicity barrier imparted by aliphatic amines.

    PubMed

    Zhang, Guoying; Gao, Bao; Huang, Hanmin

    2015-06-22

    A novel and efficient palladium-catalyzed hydroaminocarbonylation of alkenes with aminals has been developed under mild reaction conditions, and allows the synthesis of a wide range of N-alkyl linear amides in good yields with high regioselectivity. On the basis of this method, a cooperative catalytic system operating by the synergistic combination of palladium, paraformaldehyde, and acid was established for promoting the hydroaminocarbonylation of alkenes with both aromatic and aliphatic amines, which do not react well under conventional palladium-catalyzed hydroaminocarbonylation.

  7. Poly[aqua-bis(μ-benzene-1,2-dicarboxyl-ato)ethano-ltetra-lithium].

    PubMed

    Rodríguez-Cuamatzi, Patricia; Tlahuext, Hugo; Höpfl, Herbert

    2009-01-01

    In the crystal structure of the title compound [Li(4)(C(8)H(4)O(4))(2)(C(2)H(5)OH)(H(2)O)](n), there are four crystallographically independent metal centers each of which is coordinated by four O atoms. The benzene-1,2-dicarboxyl-ate groups act as bidentate-bridging ligands producing a two-dimensional coordination network parallel to the ab plane. The coordination polymer is further stabilized by coordination of water and ethanol mol-ecules by the Li(+) ions. Simultaneously, the water and ethanol mol-ecules are involved in O-H⋯O and C-H⋯π inter-actions. PMID:21582040

  8. Tetracene dicarboxylic imide and its disulfide: synthesis of ambipolar organic semiconductors for organic photovoltaic cells.

    PubMed

    Okamoto, Toshihiro; Suzuki, Tsuyoshi; Tanaka, Hideyuki; Hashizume, Daisuke; Matsuo, Yutaka

    2012-01-01

    We have designed and synthesized a new donor/acceptor-type tetracene derivative by the introduction of dicarboxylic imide and disulfide groups as electron-withdrawing and -donating units, respectively. The prepared compounds, tetracene dicarboxylic imide (TI) and its disulfide (TIDS) have high chemical and electrochemical stability as well as long-wavelength absorptions of up to 886 nm in the thin films. The crystal packing structure of TIDS molecules features face-to-face π-stacking, derived from dipole-dipole interactions. Notably, TIDS exhibited ambipolar properties of both electron-donating and -accepting natures in p-n and p-i-n heterojunction organic thin-film photovoltaic devices. Accordingly, TI and TIDS are expected to be promising compounds for designing new organic semiconductors.

  9. Terrestrial ecotoxicity of short aliphatic protic ionic liquids.

    PubMed

    Peric, Brezana; Martí, Esther; Sierra, Jordi; Cruañas, Robert; Iglesias, Miguel; Garau, Maria Antonia

    2011-12-01

    A study of the ecotoxicity of different short aliphatic protic ionic liquids (PILs) on terrestrial organisms was conducted. Tests performed within the present study include those assessing the effects of PILs on soil microbial functions (carbon and nitrogen mineralization) and terrestrial plants. The results show that the nominal lowest-observed-adverse-effect concentration (LOAEC) values were 5,000 mg/kg (dry soil) for the plant test in two species (Lolium perenne, Allium cepa), 1,000 mg/kg (dry soil) for the plant test in one species (Raphanus sativus), and 10,000 mg/kg (dry soil) for carbon and nitrogen microbial transformation tests (all concentrations are nominal). Most of the median effective concentration values (EC50) were above 1,000 mg/kg (dry soil). Based on the obtained results, these compounds can be described as nontoxic for soil microbiota and the analyzed plants, and potentially biodegradable in soils, as can be deduced from the respirometric experiment. The toxicity rises with the increase of complexity of the PILs molecule (branch and length of aliphatic chain) among the three PILs analyzed. PMID:21935980

  10. Effects of aliphatic aldehydes on the growth and patulin production of Penicillium expansum in apple juice.

    PubMed

    Taguchi, Tomoyasu; Kozutsumi, Daisuke; Nakamura, Ruka; Sato, Yoshio; Ishihara, Atsushi; Nakajima, Hiromitsu

    2013-01-01

    The effects of 16 aliphatic aldehydes with 3-10 carbons on the growth and patulin production of Penicillium expansum were examined. When P. expansum spores were inoculated into apple juice broth, some alkenals, including 2-propenal, (E)-2-butenal, (E)-2-pentenal, and (E)-2-hexenal, inhibited fungal growth and patulin production. Their minimal inhibitory concentrations were 5, 50, 80, and 80 µg/mL respectively. Vital staining indicated that these alkenals killed mycelia within 4 h. Treatment of the spores with these aldehydes also resulted in rapid loss of germination ability, within 0.5-2 d. On the other hand, aliphatic aldehydes with 8-10 carbons significantly enhanced patulin production without affecting fungal growth: 300 µg/mL of octanal and 100 µg/mL of (E)-2-octenal increased the patulin concentrations in the culture broth by as much as 8.6- and 7.8-fold as compared to that of the control culture respectively. The expression of the genes involved in patulin biosynthesis in P. expansum was investigated in mycelia cultured in apple juice broth containing 300 µg/mL of octanal for 3.5, 5, and 7 d. Transcription of the msas gene, encoding 6-methylsalicylic acid synthase, which catalyzed the first step in the patulin biosynthetic pathway was remarkably high in the 3.5-d and 5-d-old cultures as compared with the control. However, octanal did not any increase the transcription of the msas in the 7-d-old culture or that of the other two genes, IDH and the peab1, in culture. Thus the enhanced patulin accumulation with supplementation with these aldehydes is attributable to the increased amount of the msas transcript.

  11. Aliphatic and eudesmalolide esters extracted from the roots of Inula racemosa Hook

    PubMed Central

    Khan, Maria; Mir, S.R.; Ali, Abuzar; Yusuf, Mohammad; Ali, Mohammed

    2014-01-01

    Background: Phytochemical investigation of hydroalcoholic extract of the root of Inula racemosa Hook. Materials and Methods: Open silica gel column chromatographic techniques with different solvent systems was used for isolation of aliphatic and eudesmalolide esters from hydroalcoholic extract of the root of Inula racemosa. The structure elucidation of the compounds was done on the basis of spectral data analysis, chemical reactions and comparision with literature data. Results: Phytochemical investigation of the hydroalcoholic extract of the root of Inula racemosa Hook. f. led to the isolation of (5z, 13z)-n-decanyl-n-docos-5, 13-dienoate, a new fatty acid ester, two new sesquiterpenic ester identified as 15-[(13z, 18′z, 20′z)-n-tricos-13, 18, 20-trienyl]-eudesmal-4 (11), 6, 12 (13)-trien-8,14-olide-15-oate and 15- [(16′z), (21′z)-n- tetracos-16′, 21′- dienyl]-eudesmal-4 (11) 6, 12 (13)-trien-8, 14-olide-15-oate, two new eudesmanolide ester i.e. 15-[(16z)-n-monadec-16′- enyl]-eudesmal-4 (11) 6, 12 (13)-trien-8,14-olide-15-oate and 15-[(16′z)-n-tetracos-16′- enyl]-endesmal-4 (11), 6, 12 (13)-trien-8,14-olide-15-oate along with the known compound n-Hexadecanyl n-docosanoate. Conclusion: Five new phytoconstituents were identified along with one known compound as aliphatic and eudesmalolide esters from the hydroalcoholic extract of the root of Inula racemosa, as mentioned above. PMID:24695458

  12. Clickable degradable aliphatic polyesters via copolymerization with alkyne epoxy esters: synthesis and postfunctionalization with organic dyes.

    PubMed

    Teske, Nele S; Voigt, Julia; Shastri, V Prasad

    2014-07-23

    Degradable aliphatic polyesters are the cornerstones of nanoparticle (NP)-based therapeutics. In this paradigm, covalent modification of the NP with cell-targeting motifs and dyes can aid in guiding the NP to its destination and gaining visual confirmation. Therefore, strategies to impart chemistries along the polymer backbone that are amenable to easy modification, such as 1,3-dipolar cycloaddition of an azide to an alkyne (the "click reaction"), could be significant. Here we present a simple and efficient way to introduce alkyne groups at high density in aliphatic polyesters without compromising their crystallinity via the copolymerization of cyclic lactones with propargyl 3-methylpentenoate oxide (PMPO). Copolymers of lactic acid and ε-caprolactone with PMPO were synthesized with up to 9 mol % alkyne content, and accessibility of the alkyne groups to the click reaction was demonstrated using several dyes commonly employed in fluorescence microscopy and imaging (Cy3, ATTO-740, and coumarin 343). In order to establish the suitability of these copolymers as nanocarriers, copolymers were formulated into NPs, and cytocompatibility, cellular uptake, and visualization studies undertaken in HeLa cells. Dye-modified NPs exhibited no quenching, remained stable in solution for at least 10 days, showed no cytotoxicity, and were readily taken up by HeLa cells. Furthermore, in addition to enabling the incorporation of multiple fluorophores within the same NP through blending of individual dye-modified copolymers, dye-modified polyesters offer advantages over physical entrapment of dye, including improved signal to noise ratio and localization of the fluorescence signal within cells, and possess the necessary prerequisites for drug delivery and imaging.

  13. A series of Zn-4f heterometallic coordination polymers and a zinc complex containing a flexible mixed donor dicarboxylate ligand.

    PubMed

    Feng, Xun; Feng, Yu-Quan; Liu, Lang; Wang, Li-Ya; Song, Hong-Liang; Ng, Seik-Weng

    2013-06-01

    A new zinc compound, together with a corresponding series of Zn-4f heterometallic coordination polymers, namely, [Zn(H2PBDA)(PBDA)]n (1), {[Ln2(PBDA)2·2H2O] [Zn2(PBDA)2Cl2]}n [H2PBDA = 3-(pyridin-3-yl-oxy) benzene-1,2-dicarboxylic acid, and Ln = Pr(2), Nd(3), Eu(4), Gd(5), Dy(6), Ho(7), Er(8)] have been hydrothermally synthesized and characterized systematically. Polymers 2-8 feature two-dimensional (2D) 4,4 networks, containing the original 1D heterometallic double stranded chains composed of [Ln2Zn2(PBDA)2] entities. The extensive hydrogen bonding and π-π stacking interactions were observed to stabilize the extended architectures. The luminescence emission spectra of the polymers vary depending on the lanthanide(III) ion present. Informative magnetic susceptibility measurements show that the same carboxylate bridging fashion of the PBDA ligand results in the different magnetic properties occurring within the heterometallic coordination polymers. In addition, polymer 6 exhibits an interesting slow magnetic relaxation behavior at lower temperatures.

  14. In situ hydrothermal syntheses, structures and photoluminescent properties of four novel metal-organic frameworks constructed by lanthanide (Ln=Ce(III), Pr(III), Eu(III)) and Cu(I) metals with flexible dicarboxylate acids and piperazine-based ligands

    NASA Astrophysics Data System (ADS)

    Ay, Burak; Karaca, Serkan; Yildiz, Emel; Lopez, Valerie; Nanao, Max H.; Zubieta, Jon

    2016-01-01

    Four novel metal-organic frameworks,[Cu2Cl2(pyrz)]n (1) and (H2pip)n[Ln2(pydc)4(H2O)2]n (Ln=Ce (2), Pr (3) and Eu (4), H2pzdc=2,3-pyrazinedicarboxylic acid, pyrz=pyrazine, H2pydc=2,6-pyridinedicarboxylic acid, H2pip=piperazine) have been synthesized under hydrothermal conditions and characterized by the elemental analysis, ICP, Far IR (FIR), FT-IR spectra, TGA, single crystal X-ray diffraction analysis and powder X-ray diffraction (PXRD). Compound 1 is two-dimensional containing Cl-Cu-Cl sites, while the lanthanide complexes contain one-dimensional infinite Ln-O-Ln chains. All the complexes show high thermal stability. The complexes 1-3 exhibit luminescence emission bands at 584, 598 and 614 nm at room temperature when excited at 300 nm. Complex 4 exhibits bright red solid-state phosphorescence upon exposure to UV radiation at room temperature.

  15. Comparative study of two layered lanthanide dicarboxylates based on europium(III) dimers

    NASA Astrophysics Data System (ADS)

    Surblé, Suzy; Serre, Christian; Millange, Franck; Pellé, Fabienne; Férey, Gérard

    2007-02-01

    The new rare-earth dicarboxylate solid Eu 2(H 2O) 4{C 6H 10-(CO 2) 2} 3·2H 2O or MIL-94 has been isolated under hydrothermal conditions. Its layered structure, which was solved using X-ray powder diffraction data, is built up from dimers of nine-coordinated edge-sharing polyhedra linked through 1,3-cyclohexane dicarboxylate (1,3-CHC) moieties. A comparative study of MIL-94 and the layered lanthanide dicarboxylate EuBDC or Eu 2(H 2O) 2{C 6H 4-(CO 2) 2} 3, which is built up from dimers of corner-sharing polyhedra and 1,3-benzenedicarboxylate (1,3-BDC) linkers, is also reported. Crystal data for MIL-94: orthorhombic space group Pnma (no. 62) with a = 8.8470(1) Å, b = 25.0148(1) Å, c = 14.3716(4) Å and Z = 4. MIL stands for Material Institut Lavoisier.

  16. Sulfoxide-TFAA and nucleophile combination as new reagent for aliphatic C-H functionalization at indole 2α-position.

    PubMed

    Tayu, Masanori; Higuchi, Kazuhiro; Inaba, Masato; Kawasaki, Tomomi

    2013-01-21

    Aliphatic C-H functionalization at indole 2α-position mediated by acyloxythionium species 1 generated from sulfoxide and acid anhydride has been developed. The combination of sulfoxide and TFAA with O-, N- and C-nucleophiles enabled introduction of various substituents in a one-pot procedure. Especially on utilizing DMSO, the combination provided a practical and efficient method for the synthesis of a wide range of 2α-substituted indoles.

  17. Two Novel Flavin-Containing Monooxygenases Involved in Biosynthesis of Aliphatic Glucosinolates.

    PubMed

    Kong, Wenwen; Li, Jing; Yu, Qingyue; Cang, Wei; Xu, Rui; Wang, Yang; Ji, Wei

    2016-01-01

    Glucosinolates, a class of secondary metabolites from cruciferous plants, are derived from amino acids and have diverse biological activities, such as in biotic defense, depending on their side chain modification. The first structural modification step in the synthesis of aliphatic (methionine-derived) glucosinolates-S-oxygenation of methylthioalkyl glucosinolates to methylsulfinylalkyl glucosinolates-was found to be catalyzed by five flavin-containing monooxygenases (FMOs), FMOGS-OX1-5. Here, we report two additional FMOGS-OX enzymes, FMOGS-OX6, and FMOGS-OX7, encoded by At1g12130 and At1g12160, respectively. The overexpression of both FMOGS-OX6 and FMOGS-OX7 decreased the ratio of methylthioalkyl glucosinolates to the sum of methylthioalkyl and methylsulfinylalkyl glucosinolates, suggesting that the introduction of the two genes converted methylthioalkyl glucosinolates into methylsulfinylalkyl glucosinolates. Analysis of expression pattern revealed that the spatial expression of the two genes is quite similar and partially overlapped with the other FMOGS-OX genes, which are primarily expressed in vascular tissue. We further analyzed the responsive expression pattern of all the seven FMOGS-OX genes to exogenous treatment with abscisic acid, 1-aminocyclopropane-1-carboxylic acid (ACC), jasmonic acid (JA), salicylic acid, indole-3-acetic acid (IAA), and low and high temperatures. Although these genes showed same tendency toward the changing stimulus, the sensitivity of each gene was quite different. The variety in spatial expression among the FMOGS-OX genes while responding to environmental stimulus indicated a complex and finely tuned regulation of glucosinolates modifications. Identification of these two novel FMOGS-OX enzymes will enhance the understanding of glucosinolates modifications and the importance of evolution of these duplicated genes. PMID:27621741

  18. Two Novel Flavin-Containing Monooxygenases Involved in Biosynthesis of Aliphatic Glucosinolates

    PubMed Central

    Kong, Wenwen; Li, Jing; Yu, Qingyue; Cang, Wei; Xu, Rui; Wang, Yang; Ji, Wei

    2016-01-01

    Glucosinolates, a class of secondary metabolites from cruciferous plants, are derived from amino acids and have diverse biological activities, such as in biotic defense, depending on their side chain modification. The first structural modification step in the synthesis of aliphatic (methionine-derived) glucosinolates—S-oxygenation of methylthioalkyl glucosinolates to methylsulfinylalkyl glucosinolates—was found to be catalyzed by five flavin-containing monooxygenases (FMOs), FMOGS-OX1-5. Here, we report two additional FMOGS-OX enzymes, FMOGS-OX6, and FMOGS-OX7, encoded by At1g12130 and At1g12160, respectively. The overexpression of both FMOGS-OX6 and FMOGS-OX7 decreased the ratio of methylthioalkyl glucosinolates to the sum of methylthioalkyl and methylsulfinylalkyl glucosinolates, suggesting that the introduction of the two genes converted methylthioalkyl glucosinolates into methylsulfinylalkyl glucosinolates. Analysis of expression pattern revealed that the spatial expression of the two genes is quite similar and partially overlapped with the other FMOGS-OX genes, which are primarily expressed in vascular tissue. We further analyzed the responsive expression pattern of all the seven FMOGS-OX genes to exogenous treatment with abscisic acid, 1-aminocyclopropane-1-carboxylic acid (ACC), jasmonic acid (JA), salicylic acid, indole-3-acetic acid (IAA), and low and high temperatures. Although these genes showed same tendency toward the changing stimulus, the sensitivity of each gene was quite different. The variety in spatial expression among the FMOGS-OX genes while responding to environmental stimulus indicated a complex and finely tuned regulation of glucosinolates modifications. Identification of these two novel FMOGS-OX enzymes will enhance the understanding of glucosinolates modifications and the importance of evolution of these duplicated genes.

  19. Two Novel Flavin-Containing Monooxygenases Involved in Biosynthesis of Aliphatic Glucosinolates

    PubMed Central

    Kong, Wenwen; Li, Jing; Yu, Qingyue; Cang, Wei; Xu, Rui; Wang, Yang; Ji, Wei

    2016-01-01

    Glucosinolates, a class of secondary metabolites from cruciferous plants, are derived from amino acids and have diverse biological activities, such as in biotic defense, depending on their side chain modification. The first structural modification step in the synthesis of aliphatic (methionine-derived) glucosinolates—S-oxygenation of methylthioalkyl glucosinolates to methylsulfinylalkyl glucosinolates—was found to be catalyzed by five flavin-containing monooxygenases (FMOs), FMOGS-OX1-5. Here, we report two additional FMOGS-OX enzymes, FMOGS-OX6, and FMOGS-OX7, encoded by At1g12130 and At1g12160, respectively. The overexpression of both FMOGS-OX6 and FMOGS-OX7 decreased the ratio of methylthioalkyl glucosinolates to the sum of methylthioalkyl and methylsulfinylalkyl glucosinolates, suggesting that the introduction of the two genes converted methylthioalkyl glucosinolates into methylsulfinylalkyl glucosinolates. Analysis of expression pattern revealed that the spatial expression of the two genes is quite similar and partially overlapped with the other FMOGS-OX genes, which are primarily expressed in vascular tissue. We further analyzed the responsive expression pattern of all the seven FMOGS-OX genes to exogenous treatment with abscisic acid, 1-aminocyclopropane-1-carboxylic acid (ACC), jasmonic acid (JA), salicylic acid, indole-3-acetic acid (IAA), and low and high temperatures. Although these genes showed same tendency toward the changing stimulus, the sensitivity of each gene was quite different. The variety in spatial expression among the FMOGS-OX genes while responding to environmental stimulus indicated a complex and finely tuned regulation of glucosinolates modifications. Identification of these two novel FMOGS-OX enzymes will enhance the understanding of glucosinolates modifications and the importance of evolution of these duplicated genes. PMID:27621741

  20. Polyestercarbonates which exhibit improved processibility

    DOEpatents

    Krabbenhoft, Herman Otto

    1999-01-01

    The invention relates to a polyestercarbonate polymer which comprises repeating units of a mono-unsaturated aliphatic dicarboxylic acid having about 12 to about 20 carbon atoms. Preferred dicarboxylic acids for incorporation into the polymer are cis-octadec-9-enedioic acid or trans-octadec-9-enedioic acid. The use of these mono-unsaturated acids results in polymers with lower glass transition temperatures, and enhances processibility.

  1. Tailored design of ruthenium molecular catalysts with 2,2'-bypyridine-6,6'-dicarboxylate and pyrazole based ligands for water oxidation.

    PubMed

    Daniel, Quentin; Wang, Lei; Duan, Lele; Li, Fusheng; Sun, Licheng

    2016-10-01

    With the incorporation of pyrazole and DMSO as axial ligands, a series of tailor-designed Ru water oxidation catalysts [Ru(bda)(DMSO)(L)] (H2bda = 2,2'-bypyridine-6,6'-dicarboxylic acid; DMSO = dimethyl sulfoxide; L = pyrazole, A-1; 4-Br-3-methyl pyrazole, B-1) and [Ru(bda)(L)2] (L = pyrazole, A-2; 4-Br-3-methyl pyrazole, B-2) have been generated in situ from their corresponding precursors [Ru(κ3(O,N,N)-bda)(DMSO)x(L)3-x] which are in a zwitterionic form with an extra pyrazole based ligand in the equatorial position. Formation of the active catalyst has been investigated under pH 1.0 conditions. Electrochemistry and water oxidation activity of these catalysts were investigated. By fine tuning of the catalyst structure, the turnover frequency was increased up to 500 s(-1) and the stability over 6000 turnovers. PMID:27241474

  2. Molar Absorptivity and Concentration-Dependent Quantum Yield of Fe(II) Photo-Formation for the Aqueous Solutions of Fe(III)-Dicarboxylate Complexes

    NASA Astrophysics Data System (ADS)

    Hitomi, Y.; Arakaki, T.

    2009-12-01

    Redox cycles of iron in the aquatic environment affect formation of reactive oxygen species such as hydrogen peroxide and hydroxyl radicals, which in turn determines lifetimes of many organic compounds. Although aqueous Fe(III)-dicarboxylate complexes are considered to be important sources of photo-formed Fe(II), molar absorptivity and quantum yield of Fe(II) formation for individual species are not well understood. We initiated a study to characterize Fe(II) photo-formation from Fe(III)-dicarboxylates with the concentration ranges that are relevant to the natural aquatic environment. The Visual MINTEQ computer program was used to calculate the equilibrium concentrations of individual Fe(III)-dicarboxylate species. The molar absorptivity of Fe(III)-dicarboxylate species was obtained by UV-VIS spectrophotometer, and the product of the quantum yield and the molar absorptivity of Fe(III)-dicarboxylate species were obtained from photochemical experiments. These experimental data were combined with the calculated equilibrium Fe(III)-dicarboxylate concentrations to determine individual molar absorptivity and quantum yield of Fe(II) photo-formation for a specific Fe(III)-dicarboxylate species. We used initial concentrations of less than 10 micromolar Fe(III) to study the photochemical formation of Fe(II). Dicarboxylate compounds studied include oxalate, malonate, succinate, malate, and phthalate. We report molar absorptivity and concentration-dependent quantum yields of Fe(II) photo-formation of individual Fe(III)-dicarboxylates.

  3. Carboxylic acid accelerated formation of diesters

    DOEpatents

    Tustin, G.C.; Dickson, T.J.

    1998-04-28

    This invention pertains to accelerating the rate of formation of 1,1-dicarboxylic esters from the reaction of an aldehyde with a carboxylic acid anhydride or a ketene in the presence of a non-iodide containing a strong Bronsted acid catalyst by the addition of a carboxylic acid at about one bar pressure and between about 0 and 80 C in the substantial absence of a hydrogenation or carbonylation catalyst.

  4. Carboxylic acid accelerated formation of diesters

    DOEpatents

    Tustin, Gerald Charles; Dickson, Todd Jay

    1998-01-01

    This invention pertains to accelerating the rate of formation of 1,1-dicarboxylic esters from the reaction of an aldehyde with a carboxylic acid anhydride or a ketene in the presence of a non-iodide containing a strong Bronsted acid catalyst by the addition of a carboxylic acid at about one bar pressure and between about 0.degree. and 80.degree. C. in the substantial absence of a hydrogenation or carbonylation catalyst.

  5. 40 CFR 721.10605 - Polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polyoxyalkylene ether, polymer with..., polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic). (a) Chemical substance and... polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (PMN P-11-485) is...

  6. 40 CFR 721.10605 - Polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polyoxyalkylene ether, polymer with..., polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic). (a) Chemical substance and... polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (PMN P-11-485) is...

  7. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  8. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  9. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  10. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  11. 40 CFR 721.9952 - Alkoxylated aliphatic diisocyanate allyl ether (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... allyl ether (generic). 721.9952 Section 721.9952 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.9952 Alkoxylated aliphatic diisocyanate allyl ether... identified generically as alkoxylated aliphatic diisocyanate allyl ether (PMN P-00-0353) is subject...

  12. 40 CFR 721.9952 - Alkoxylated aliphatic diisocyanate allyl ether (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... allyl ether (generic). 721.9952 Section 721.9952 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.9952 Alkoxylated aliphatic diisocyanate allyl ether... identified generically as alkoxylated aliphatic diisocyanate allyl ether (PMN P-00-0353) is subject...

  13. Preferences in removal of aliphatic and aromatic gasoline components by biofiltration under varied loading.

    PubMed

    Halecky, Martin; Paca, Jan; Kozliak, Evguenii I

    2012-01-01

    Removal of gasoline vapors from waste air was investigated in a bench-scale perlite biofilter for three aromatic-to-aliphatic mass ratios (62/38, 92/8 and 44/56) under different loads, varied by changing both the substrate inlet concentration and air flow rate. The measurement of concentration profiles along the bed height allowed for an assessment of interactions between the aromatic and aliphatic fractions of gasoline. Variations in both the inlet concentrations and empty bed residence time significantly influenced the removal of aliphatic gasoline components. Except for the lowest organic loads, the whole biofilter bed was required for achieving an acceptable removal efficiency of aliphatic hydrocarbons. The presence of large amounts of aromatics negatively impacted the removal of aliphatics. By contrast, the aromatic gasoline components were near-completely removed from any mixtures; the bulk of them were degraded in the first (out of three) biofilter section, even at high concentrations of aliphatic hydrocarbons. The observed effect was shown to be due to competitive interactions of aliphatic and aromatic components, which is consistent with the biological steps being rate limiting. Mass transfer, particularly for aliphatic components due to their high Henry's law constants, was shown to be rate-limiting under extreme scenarios, such as low loading rates and EBRT.

  14. A statistical approach to the interpretation of aliphatic hydrocarbon distributions in marine sediments

    USGS Publications Warehouse

    Rapp, J.B.

    1991-01-01

    Q-mode factor analysis was used to quantitate the distribution of the major aliphatic hydrocarbon (n-alkanes, pristane, phytane) systems in sediments from a variety of marine environments. The compositions of the pure end members of the systems were obtained from factor scores and the distribution of the systems within each sample was obtained from factor loadings. All the data, from the diverse environments sampled (estuarine (San Francisco Bay), fresh-water (San Francisco Peninsula), polar-marine (Antarctica) and geothermal-marine (Gorda Ridge) sediments), were reduced to three major systems: a terrestrial system (mostly high molecular weight aliphatics with odd-numbered-carbon predominance), a mature system (mostly low molecular weight aliphatics without predominance) and a system containing mostly high molecular weight aliphatics with even-numbered-carbon predominance. With this statistical approach, it is possible to assign the percentage contribution from various sources to the observed distribution of aliphatic hydrocarbons in each sediment sample. ?? 1991.

  15. Surface Characterization of Aliphatic Polyester -g- Phosphorylcholine Copolymers

    NASA Astrophysics Data System (ADS)

    Zhang, Xiongfei; Emrick, Todd; Hsu, Shaw L.

    2007-03-01

    In order to control biodegradation behavior of a class of polyesters, hydrophilic functional groups were grafted onto the main chains. Phosphorylcholine (PC) molecules with azide attached at the end were synthesized. Due to their excellent biocompatibility and hydrophilicity, they have been covalently coupled to biodegradable aliphatic polyesters via a ``click'' cycloaddition reaction to produce amphiphilic graft copolymers. A series of copolymers were prepared by varying the molar incorporation of PC groups. Surface properties of the copolymers were examined to further explore their applications in drug delivery systems. Grazing angle reflection infrared spectroscopy was employed to determine segmental orientation at the film surface. XPS was used to verify surface composition. A water adsorption experiment was carried out to determine the water permeation rate. The improvement in hydrophilicity was confirmed by a water contact experiment. Results indicate that the graft copolymers were promising in drug delivery systems.

  16. Antitumor Agents 293. Non-toxic Dimethyl-4,4′-dimethoxy-5,6,5′,6′-dimethylenedioxybiphenyl-2,2′-dicarboxylate (DDB) Analogs Chemosensitize Multidrug Resistant Cancer Cells to Clinical Anticancer Drugs

    PubMed Central

    Hung, Hsin-Yi; Ohkoshi, Emika; Goto, Masuo; Bastow, Kenneth F.; Nakagawa-Goto, Kyoko; Lee, Kuo-Hsiung

    2012-01-01

    Novel dimethyl-4,4′-dimethoxy-5,6,5′,6′-dimethylenedioxybiphenyl-2,2′-dicarboxylate (DDB) analogs were designed and synthesized to improve their chemosensitizing action on KBvin (vincristine resistant nasopharyngeal carcinoma) cells, a multi-drug resistant cell line over-expressing P-glycoprotein (P-gp). Structure-activity relationship analysis showed that aromatic and bulky aliphatic side chains at the 2,2′-positions effectively and significantly sensitized P-gp overexpressing multidrug resistant (MDR) cells to anticancer drugs, such as paclitaxel (TAX), vincristine (VCR), and doxorubicin (DOX). DDB derivatives 16 and 23 showed 5–10 times more effective reversal ability than verapamil (VRP) for TAX and VCR. Analog 6 also exhibited five times greater chemosensitizing effect against DOX than VRP. Importantly, no cytotoxicity was observed by the active DDB analogs against both non-MDR and MDR cells, suggesting that DDB analogs serve as the novel lead compounds for the development of chemosensitizers to overcome MDR phenotype. The mechanism of action studies demonstrated that effective inhibition of P-glycoprotein by DDB analogs dramatically elevated cellular concentration of anticancer drugs. PMID:22612652

  17. Conjugated dicarboxylate anodes for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Armand, M.; Grugeon, S.; Vezin, H.; Laruelle, S.; Ribière, P.; Poizot, P.; Tarascon, J.-M.

    2009-02-01

    Present Li-ion batteries for portable electronics are based on inorganic electrodes. For upcoming large-scale applications the notion of materials sustainability produced by materials made through eco-efficient processes, such as renewable organic electrodes, is crucial. We here report on two organic salts, Li2C8H4O4 (Li terephthalate) and Li2C6H4O4(Li trans-trans-muconate), with carboxylate groups conjugated within the molecular core, which are respectively capable of reacting with two and one extra Li per formula unit at potentials of 0.8 and 1.4V, giving reversible capacities of 300 and 150mAhg-1. The activity is maintained at 80∘C with polyethyleneoxide-based electrolytes. A noteworthy advantage of the Li2C8H4O4 and Li2C6H4O4 negative electrodes is their enhanced thermal stability over carbon electrodes in 1M LiPF6 ethylene carbonate-dimethyl carbonate electrolytes, which should result in safer Li-ion cells. Moreover, as bio-inspired materials, both compounds are the metabolites of aromatic hydrocarbon oxidation, and terephthalic acid is available in abundance from the recycling of polyethylene terephthalate.

  18. The role of essential fatty acids in development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acids are aliphatic monocarboxylic acids. They are classified as saturated, monounsaturated, or polyunsaturated fatty acids depending upon the number of double bonds in the carbon chain. Saturated fatty acids have no double bonds, monounsaturated fatty acids have 1 double bond, and polyunsat...

  19. Highly Anisotropic Thermal Expansion in Molecular Films of Dicarboxylic Fatty Acids

    SciTech Connect

    Tamam L.; Ocko B.; Kraack, H.; Sloutskin, E.; Deutsch, M.

    2012-05-25

    Angstrom-resolution x-ray measurements reveal the existence of two-dimensional (2D) crystalline order in molecularly thin films of surface-parallel-oriented fatty diacid molecules supported on a liquid mercury surface. The thermal expansion coefficients along the two unit cell vectors are found to differ 17-fold. The high anisotropy of the 2D thermal expansion and the crystalline coherence length are traced to the different bonding in the two directions: van der Waals normal to, and covalent plus hydrogen bonding along the molecular backbone axis. Similarities with, and differences from, negative thermal expansion materials are discussed.

  20. [A novel nano-hydroxyapatite/aliphatic polyesteramide composite].

    PubMed

    Deng, Xia; Chen, Zhiqing; Qian, Zhiyong; Liu, Caibing; Li, Hong

    2008-04-01

    Hydrothermally synthesized nano-hydroxyapatite (n-HA) varying in weight from 10% to 30% was used as filler to make nanocomposites with novel aliphatic polyesteramide (PEA) in our laboratory. The structure and properties of PEA and its n-HA composites were investigated through transmission electron microscopy, infrared spectrometry, X-ray diffractioin, scanning electron microscopy and energy spectrometry. The shape and size of the n-HA crystals are similar to those of the apatite crystals in natural bone. Molecule interactions are present between the n-HA and PEA in the composite, which allows the uniform dispersion of n-HA in PEA matrix. This contributes enhanced mechanical property and bioactivity to the composite. The cytocompatibility of the composites has been investigated by culturing osteoblasts on the membranes. Good cell attachment and proliferation manner were observed on the membranes after 1 week. These results suggest that the PEA/n-HA composites prepared in this study may serve as potential candidate scaffold for tissue engineering.

  1. Liquid-crystalline aromatic-aliphatic copolyester bioresorbable polymers.

    PubMed

    de Oca, Horacio Montes; Wilson, Joanne E; Penrose, Andrew; Langton, David M; Dagger, Anthony C; Anderson, Melissa; Farrar, David F; Lovell, Christopher S; Ries, Michael E; Ward, Ian M; Wilson, Andrew D; Cowling, Stephen J; Saez, Isabel M; Goodby, John W

    2010-10-01

    The synthesis and characterisation of a series of liquid-crystalline aromatic-aliphatic copolyesters are presented. Differential scanning calorimetry showed these polymers have a glass transition temperature in the range 72 degrees C-116 degrees C. Polarised optical microscopy showed each polymer exhibits a nematic mesophase on heating to the molten state at temperatures below 165 degrees C. Melt processing is demonstrated by the production of injection moulded and compression moulded specimens with Young's modulus of 5.7 +/- 0.3 GPa and 2.3 +/- 0.3 GPa, respectively. Wide-angle X-ray scattering data showed molecular orientation is responsible for the increase of mechanical properties along the injection direction. Degradation studies in the temperature range 37 degrees C-80 degrees C are presented for one polymer of this series and a kinetic constant of 0.002 days(-1) is obtained at 37 degrees C assuming a first order reaction. The activation energy (83.4 kJ mol(-1)) is obtained following the Arrhenius analysis of degradation, showing degradation of this material is less temperature sensitive compared with other commercially available biodegradable polyesters. In vitro and in vivo biocompatibility data are presented and it is shown the unique combination of degradative, mechanical and biological properties of these polymers may represent in the future an alternative for medical device manufacturers.

  2. Organochlorine compounds and aliphatic hydrocarbons in Pacific walrus blubber.

    PubMed

    Seagars, D J; Garlich-Miller, J

    2001-01-01

    Blubber samples were collected from 8 male and 19 female Pacific walrus (Odobenus rosmarus divergens) taken during a 1991 joint USA/USSR cruise traveling widely through the Bering Sea. Dieldrin was found at a level similar to that reported 10 years earlier; oxychlordane was found at a slightly higher concentration than reported previously (Taylor et aL, 1989). Heptachlor epoxide was detected for the first time and found at a low concentration. An initial testing for alpha-, beta- and gamma-HCH detected concentrations similar to those in other Bering Sea pinnipeds. Mean summation of PCB was 0.45 microg g(-1) wet weight in males and 0.16 microg g(-1) in females; only one sample was > 1 microg g(-1). Traces of aliphatic hydrocarbons were detected in all sampled animals, only pristane (x = 0.48 microg g(-1)) was found in concentrations > 1 microg g(-1). Small sample sizes, a lack of samples from immature animals, and uniformly low concentrations of contaminants precluded meaningful analysis of age-related effects and regional differences.

  3. Aliphatic polyesters for medical imaging and theranostic applications.

    PubMed

    Nottelet, Benjamin; Darcos, Vincent; Coudane, Jean

    2015-11-01

    Medical imaging is a cornerstone of modern medicine. In that context the development of innovative imaging systems combining biomaterials and contrast agents (CAs)/imaging probes (IPs) for improved diagnostic and theranostic applications focuses intense research efforts. In particular, the classical aliphatic (co)polyesters poly(lactide) (PLA), poly(lactide-co-glycolide) (PLGA) and poly(ɛ-caprolactone) (PCL), attract much attention due to their long track record in the medical field. This review aims therefore at providing a state-of-the-art of polyester-based imaging systems. In a first section a rapid description of the various imaging modalities, including magnetic resonance imaging (MRI), optical imaging, computed tomography (CT), ultrasound (US) and radionuclide imaging (SPECT, PET) will be given. Then, the two main strategies used to combine the CAs/IPs and the polyesters will be discussed. In more detail we will first present the strategies relying on CAs/IPs encapsulation in nanoparticles, micelles, dendrimers or capsules. We will then present chemical modifications of polyesters backbones and/or polyester surfaces to yield macromolecular imaging agents. Finally, opportunities offered by these innovative systems will be illustrated with some recent examples in the fields of cell labeling, diagnostic or theranostic applications and medical devices.

  4. Process for the synthesis of aliphatic alcohol-containing mixtures

    DOEpatents

    Greene, M.I.; Gelbein, A.P.

    1984-10-16

    A process for the synthesis of mixtures which include saturated aliphatic alcohols is disclosed. In the first step of the process, the first catalyst activation stage, a catalyst, which comprises the oxides of copper, zinc, aluminum, potassium and one or two additional metals selected from the group consisting of chromium, magnesium, cerium, cobalt, thorium and lanthanum, is partially activated. In this step, a reducing gas stream, which includes hydrogen and at least one inert gas, flows past the catalyst at a space velocity of up to 5,000 liters (STP) per hour, per kilogram of catalyst. The partially activated catalyst is then subjected to the second step of the process, second-stage catalyst activation. In this step, the catalyst is contacted by an activation gas stream comprising hydrogen and carbon monoxide present in a volume ratio of 0.5:1 and 4:1, respectively, at a temperature of 200 to 450 C and a pressure of between 35 and 200 atmospheres. The activation gas flows at a space velocity of from 1,000 to 20,000 liters (STP) per hour, per kilogram of catalyst. Second-stage activation continues until the catalyst is contacted with at least 500,000 liters (STP) of activation gas per kilogram of catalyst. The fully activated catalyst, in the third step of the process, contacts a synthesis gas stream comprising hydrogen and carbon monoxide.

  5. Process for the synthesis of aliphatic alcohol-containing mixtures

    DOEpatents

    Greene, Marvin I.; Gelbein, Abraham P.

    1984-01-01

    A process for the synthesis of mixtures which include saturated aliphatic alcohols is disclosed. In the first step of the process, the first catalyst activation stage, a catalyst, which comprises the oxides of copper, zinc, aluminum, potassium and one or two additional metals selected from the group consisting of chromium, magnesium, cerium, cobalt, thorium and lanthanum, is partially activated. In this step, a reducing gas stream, which includes hydrogen and at least one inert gas, flows past the catalyst at a space velocity of up to 5,000 liters (STP) per hour, per kilogram of catalyst. The partially activated catalyst is then subjected to the second step of the process, second-stage catalyst activation. In this step, the catalyst is contacted by an activation gas stream comprising hydrogen and carbon monoxide present in a volume ratio of 0.5:1 and 4:1, respectively, at a temperature of 200.degree. to 450.degree. C. and a pressure of between 35 and 200 atmospheres. The activation gas flows at a space velocity of from 1,000 to 20,000 liters (STP) per hour, per kilogram of catalyst. Second-stage activation continues until the catalyst is contacted with at least 500,000 liters (STP) of activation gas per kilogram of catalyst. The fully activated catalyst, in the third step of the process, contacts a synthesis gas stream comprising hydrogen and carbon monoxide.

  6. Shape memory polymers based on uniform aliphatic urethane networks

    SciTech Connect

    Wilson, T S; Bearinger, J P; Herberg, J L; Marion III, J E; Wright, W J; Evans, C L; Maitland, D J

    2007-01-19

    Aliphatic urethane polymers have been synthesized and characterized, using monomers with high molecular symmetry, in order to form amorphous networks with very uniform supermolecular structures which can be used as photo-thermally actuable shape memory polymers (SMPs). The monomers used include hexamethylene diisocyanate (HDI), trimethylhexamethylenediamine (TMHDI), N,N,N{prime},N{prime}-tetrakis(hydroxypropyl)ethylenediamine (HPED), triethanolamine (TEA), and 1,3-butanediol (BD). The new polymers were characterized by solvent extraction, NMR, XPS, UV/VIS, DSC, DMTA, and tensile testing. The resulting polymers were found to be single phase amorphous networks with very high gel fraction, excellent optical clarity, and extremely sharp single glass transitions in the range of 34 to 153 C. Thermomechanical testing of these materials confirms their excellent shape memory behavior, high recovery force, and low mechanical hysteresis (especially on multiple cycles), effectively behaving as ideal elastomers above T{sub g}. We believe these materials represent a new and potentially important class of SMPs, and should be especially useful in applications such as biomedical microdevices.

  7. Electrospun aliphatic polycarbonates as tailored tissue scaffold materials.

    PubMed

    Welle, Alexander; Kröger, Mario; Döring, Manfred; Niederer, Kerstin; Pindel, Elvira; Chronakis, Ioannis S

    2007-04-01

    Two different aliphatic polycarbonates were synthesised from CO(2) and the respective epoxides. Poly(propyl carbonate) (PPC) was prepared by heterogeneous catalysis with zinc glutarate. Poly(cyclohexyl carbonate) (PCHC) was prepared via living copolymerisation homogeneously catalysed by a 3-amino-2-cyanoimidoacrylate zinc acetate complex and subjected to electrospinning. The obtained nanofibres had a well-defined morphology free of beads along the fibres and with slightly porous structures on their surface. Subsequently, low-power deep UV irradiations, previously applied for photochemical surface modifications of two-dimensional and three-dimensional scaffolds from biostable polymers, were performed. Here, an effect on surface and bulk properties of PPC nanofibres was observed. Surface modifications of both polymers affected plasma protein adsorption. Photochemical bulk modifications observed for the first time on PPC nanofibres are indicating the possibility of spatial control of biodegradation rates, hence allow for control of the progression of host/implant interactions in vivo. In particular PPC was used for cell culture of L929 fibroblasts and primary rat hepatocytes. Even delicate primary cells showed good adhesion to the scaffolds and high viability.

  8. Aliphatic hydrocarbons in Great Barrier Reef organisms and environment

    NASA Astrophysics Data System (ADS)

    Coates, M.; Connell, D. W.; Bodero, J.; Miller, G. J.; Back, R.

    1986-07-01

    This investigation was undertaken to assess the chemical nature, occurrence, and possible origin of petroleum hydrocarbons in the Great Barrier Reef ecosystem. Aliphatic hydrocarbons in surface sediments, water, and a suite of seven species from widely separated coral reefs in the Great Barrier Reef area were analysed by gas chromatography, and by gas chromatography coupled with mass spectrometry. The hydrocarbons found were substantially of biogenic origin. The major components were n-pentadecane, n-heptadecane, pristane and mono-alkenes based on heptadecane, and were believed to originate from benthic algae and phytoplankton. There was no evidence to suggest that lipid content had any influence on hydrocarbon content. Hydrocarbons from the organisms and sediments have characteristic composition patterns which would be altered by the presence of petroleum hydrocarbons. An unresolved complex mixture, usually considered indicative of petroleum contamination, was found in greater than trace amounts only in Holothuria (sea cucumber) and Acropora (coral) from the Capricorn Group, and in some sediment samples from the Capricorn Group and Lizard Island area.

  9. Synthesis and characterization of water-soluble chitosan grafted with hydrophilic aliphatic polyester.

    PubMed

    Chen, Jiajia; Zheng, Liuchun; Chen, Xiaonong; Wang, Zhaodong; Li, Chuncheng; Xiao, Yaonan; Guan, Guohu; Zhu, Wenxiang

    2015-03-01

    Traditionally, hydrophobic aliphatic polyester has been employed to modify chitosan and organic soluble or swellable graft copolymers have been obtained. In this work, linear poly(butylene tartrate) (PBT) with hydrophilic pendant hydroxyl groups, which was synthesized by direct polycondensation of tartaric acid and butanediol under mild condition, was chosen to modify chitosan and synthesize PBT grafted chitosan (CS-g-PBT) with the mediation of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide in aqueous solution of an ionic liquid. The chain length of the grafted PBT could be facilely controlled by varying the molecular weight of PBT. The chemical structures of CS-g-PBT were systematically characterized by 1H NMR, attenuated total reflectance Fourier transform infrared and wide-angle X-ray diffraction. The thermal properties were investigated by thermogravimetric analysis and differential scanning calorimetry. The water solubility of chitosan has been effectively improved after grafting with PBT and a water-soluble chitosan derivative has been synthesized. Meanwhile, the water solubility of grafts varies regularly with chain length of grafted PBT. PMID:25576746

  10. Aliphatic hyperbranched polyester: a new building block in the construction of multifunctional nanoparticles and nanocomposites.

    PubMed

    Santra, Santimukul; Kaittanis, Charalambos; Perez, J Manuel

    2010-04-20

    Herein we report the design and synthesis of multifunctional hyperbranched polyester-based nanoparticles and nanocomposites with properties ranging from magnetic, fluorescence, antioxidant and X-ray contrast. The fabrication of these nanostructures was achieved using a novel aliphatic and biodegradable hyperbranched polyester (HBPE) synthesized from readily available diethyl malonate. The polymer's globular structure with functional surface carboxylic groups and hydrophobic cavities residing in the polymer's interior allows for the formation of multifunctional polymeric nanoparticles, which are able to encapsulate a diversity of hydrophobic cargos. Via simple surface chemistry modifications, the surface carboxylic acid groups were modified to yield nanoparticles with a variety of surface functionalizations, such as amino, azide and propargyl groups, which mediated the conjugation of small molecules. This capability achieved the engineering of the HBPE nanoparticle surface for specific cell internalization studies and the formation of nanoparticle assemblies for the creation of novel nanocomposites that retained, and in some cases enhanced, the properties of the parental nanoparticle building blocks. Considering these results, the HBPE polymer, nanoparticles and composites should be ideal for biomedical, pharmaceutical, nanophotonics applications. PMID:19957939

  11. Aqueous Phase Photo-Oxidation of Succinic Acid: Changes in Hygroscopic Properties and Reaction Products

    NASA Astrophysics Data System (ADS)

    Hudson, P. K.; Ninokawa, A.; Hofstra, J.; de Lijser, P.

    2013-12-01

    Atmospheric aerosol particles have been identified as important factors in understanding climate change. The extent to which aerosols affect climate is determined, in part, by hygroscopic properties which can change as a result of atmospheric processing. Dicarboxylic acids, components of atmospheric aerosol, have a wide range of hygroscopic properties and can undergo oxidation and photolysis reactions in the atmosphere. In this study, the hygroscopic properties of succinic acid aerosol, a non-hygroscopic four carbon dicarboxylic acid, were measured with a humidified tandem differential mobility analyzer (HTDMA) and compared to reaction products resulting from the aqueous phase photo-oxidation reaction of hydrogen peroxide and succinic acid. Reaction products were determined and quantified using gas chromatography-flame ionization detection (GC-FID) and GC-mass spectrometry (GC-MS) as a function of hydrogen peroxide:succinic acid concentration ratio and photolysis time. Although reaction products include larger non-hygroscopic dicarboxylic acids (e.g. adipic acid) and smaller hygroscopic dicarboxylic acids (e.g. malonic and oxalic acids), comparison of hygroscopic growth curves to Zdanovskii-Stokes-Robinson (ZSR) predictions suggests that the hygroscopic properties of many of the product mixtures are largely independent of the hygroscopicity of the individual components. This study provides a framework for future investigations to fully understand and predict the role of chemical reactions in altering atmospheric conditions that affect climate.

  12. Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

    EPA Science Inventory

    This project evaluated the potential of an innovative approach to aquifer restoration: enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (...

  13. Field Evaluations Test Plan for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie

    2005-01-01

    The objective of this project is to qualify candidate alternatives to Aliphatic Isocyanate Polyurethane coatings under the specifications for the standard system. This project will compare coating performance of the proposed alternatives to existing coating systems or standards.

  14. Syntheses and some features of five new cyclohexane-1,3-dicarboxylates with multiple stereogenic centers

    NASA Astrophysics Data System (ADS)

    Ismiyev, Arif M.; Maharramov, Abel M.; Aliyeva, Rafiga A.; Askerov, Rizvan K.; Mahmudov, Kamran T.; Kopylovich, Maximilian N.; Naïli, Houcine; Pombeiro, Armando J. L.

    2013-01-01

    The condensation of diethyl 4-hydroxy-4-methyl-6-oxo-2-(4-substitutedphenyl)-cyclohexane-1,3-dicarboxylates and N'-(2-chloropropyl)ethane-1,2-diamine leads to diethyl 1-(2-chloropropyl)-9-hydroxy-9-methyl-7-phenyl-1,4-diazaspiro[4.5]decane-6,8-dicarboxylate (2) and its para-substituted methyl (1), chloro (3), bromo (4), and nitro (5) derivatives with a new stereogenic center, which were fully characterized by elemental analysis, ESI-MS, IR, 1H and 13C NMR spectroscopies and X-ray single-crystal analysis (for 2). The condensation reaction is regioselective, only cyclohexanone carbonyl moiety undergoes the transformation, leaving the β-keto ester carbonyls unreacted. Withing the compounds 1-5, the increase in the Hammett's σp, related normal σpn, inductive σI, negative σp- and positive σp+ polar conjugation and Taft's σpo substituent constants generally leads to the corresponding drift of δOsbnd H and δNsbnd H NMR chemical shifts to lower field.

  15. Radiation induced effects in segmented poly(siloxaneurethaneureas) based on aliphatic and aromatic diisocyanates

    NASA Astrophysics Data System (ADS)

    Przybytniak, Grażyna; Kornacka, Ewa; Kozakiewicz, Janusz; Przybylski, Jarosław

    2007-12-01

    Poly(siloxaneurethaneureas) (PSURURs) prepared from aromatic and aliphatic isocyanates were investigated upon exposure to ionising radiation. Radicals are formed both in siloxane and urethane segments. In comparison with aliphatic analogues it was found that in aromatic PSURURs: (1) concentration of all radicals is lower, (2) relative concentration of methylene radicals formed in siloxane units is higher, (3) the radiation yield of H 2 is more than three times smaller and (4) it seems that efficiency of cross-linking is less significant.

  16. Recent Advances in the Functionalization of Aliphatic Polyesters by Ring-Opening Polymerization

    NASA Astrophysics Data System (ADS)

    Lecomte, Philippe; Jerome, Christine

    Two main strategies aiming at synthesizing aliphatic polyesters bearing pendant functional groups will be reported. The first one is based on the synthesis and the polymerization of lactones substituted by various functional groups. The direct grafting of functional groups onto aliphatic polyesters is the second strategy. Last but not least, the association of these two strategies is very promising in order to overcome their respective limitations.

  17. Sources and distribution of aliphatic and polyaromatic hydrocarbons in sediments from the Neuquen River, Argentine Patagonia.

    PubMed

    Monza, Liliana B; Loewy, Ruth M; Savini, Mónica C; Pechen de d'Angelo, Ana M

    2013-01-01

    Spatial distribution and probable sources of aliphatic and polyaromatic hydrocarbons (AHs, PAHs) were investigated in surface sediments collected along the bank of the Neuquen River, Argentina. Total concentrations of aliphatic hydrocarbons ranged between 0.41 and 125 μg/g dw. Six stations presented low values of resolved aliphatic hydrocarbons and the n-alkane distribution indexes applied suggested a clear biogenic source. These values can be considered the baseline levels of aliphatic hydrocarbons for the river sediments. This constitutes important information for the assessment of future impacts since a strong impulse in the exploitation of shale gas and shale oil in these zones is nowadays undergoing. For the other 11 stations, a mixture of aliphatic hydrocarbons of petrogenic and biogenic origin was observed. The spatial distribution reflects local inputs of these pollutants with a significant increase in concentrations in the lower course, where two major cities are located. The highest values of total aliphatic hydrocarbons were found in this sector which, in turn, was the only one where individual PAHs were detected.

  18. THE CARRIERS OF THE INTERSTELLAR UNIDENTIFIED INFRARED EMISSION FEATURES: AROMATIC OR ALIPHATIC?

    SciTech Connect

    Li Aigen; Draine, B. T. E-mail: draine@astro.princeton.edu

    2012-12-01

    The unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 {mu}m, commonly attributed to polycyclic aromatic hydrocarbon (PAH) molecules, have been recently ascribed to coal- or kerogen-like organic nanoparticles with a mixed aromatic-aliphatic structure. However, we show in this Letter that this hypothesis is inconsistent with observations. We estimate the aliphatic fraction of the UIE carriers based on the observed intensities of the 3.4 {mu}m and 6.85 {mu}m emission features by attributing them exclusively to aliphatic C-H stretch and aliphatic C-H deformation vibrational modes, respectively. We derive the fraction of carbon atoms in aliphatic form to be <15%. We conclude that the UIE emitters are predominantly aromatic, with aliphatic material at most a minor part of the UIE carriers. The PAH model is consistent with astronomical observations and PAHs dominate the strong UIE bands.

  19. Two- and three-dimensional networks of gadolinium(III) with dicarboxylate ligands: synthesis, crystal structure, and magnetic properties.

    PubMed

    Cañadillas-Delgado, Laura; Pasan, Jorge; Fabelo, Oscar; Hernandez-Molina, María; Lloret, Francesc; Julve, Miguel; Ruiz-Pérez, Catalina

    2006-12-25

    Four gadolinium(III) complexes with dicarboxylate ligands of formulas [Gd2(mal)3(H2O)5]n.2nH2O (1), [Gd2(mal)3(H2O)6]n (2), [NaGd(mal)(ox)(H2O)3]n (3), and [Gd2(ox)3(H2O)6]n.2.5nH2O (4) (mal = malonate; ox = oxalate) have been prepared, and their magnetic properties have been investigated as a function of the temperature. The structures of 1-3 have been determined by X-ray diffraction methods. The crystal structure of 4 was already known, and it is made of hexagonal layers of Gd atoms that are bridged by bis-bidentate oxalate. Compound 1 is isostructural with the europium(III) malonate complex [Eu2(mal)3(H2O)5]n.2nH2O,1 whose structure was reported elsewhere. The Gd atoms in 1 define a two-dimensional network where a terminal bidentate and bridging bidentate/bis-monodentate and tris-bidentate coordination modes of malonate occur. Compound 2 has a three-dimensional structure with a structural phase transition at 226 K, which involves a change of the space group from I2/a to Ia. Although its structure at room temperature was already known, that below 226 K was not. Pairs of Gd atoms with a double oxo-carboxylate bridge occur in both phases, and the main differences between both structures deal with the Gd environment and the H-bond pattern. 3 is also a three-dimensional compound, and it was obtained by reacting Gd(III) ions with malonic acid in a silica gel medium. Oxalic acid results as an oxidized product of the malonic acid, and single crystals of the heteroleptic complex were produced. The Gd atoms in 3 are connected through bis-bidentate oxalate and carboxylate-malonate bridges in the anti-anti and anti-syn coordination modes. Compounds 1 and 2 exhibit weak but significant ferromagnetic couplings between the Gd(III) ions through the single (1) and double (2) oxo-carboxylate bridges, whereas antiferromagnetic interactions across the bis-bidentate oxalate account for the overall antiferromagnetic behavior observed in 3 and 4.

  20. Aliphatic polyester block polymers: renewable, degradable, and sustainable.

    PubMed

    Hillmyer, Marc A; Tolman, William B

    2014-08-19

    Nearly all polymers are derived from nonrenewable fossil resources, and their disposal at their end of use presents significant environmental problems. Nonetheless, polymers are ubiquitous, key components in myriad technologies and are simply indispensible for modern society. An important overarching goal in contemporary polymer research is to develop sustainable alternatives to "petro-polymers" that have competitive performance properties and price, are derived from renewable resources, and may be easily and safely recycled or degraded. Aliphatic polyesters are particularly attractive targets that may be prepared in highly controlled fashion by ring-opening polymerization of bioderived lactones. However, property profiles of polyesters derived from single monomers (homopolymers) can limit their applications, thus demanding alternative strategies. One such strategy is to link distinct polymeric segments in an A-B-A fashion, with A and B chosen to be thermodynamically incompatible so that they can self-organize on a nanometer-length scale and adopt morphologies that endow them with tunable properties. For example, such triblock copolymers can be useful as thermoplastic elastomers, in pressure sensitive adhesive formulations, and as toughening modifiers. Inspired by the tremendous utility of petroleum-derived styrenic triblock copolymers, we aimed to develop syntheses and understand the structure-property profiles of sustainable alternatives, focusing on all renewable and all readily degradable aliphatic polyester triblocks as targets. Building upon oxidation chemistry reported more than a century ago, a constituent of the peppermint plant, (-)-menthol, was converted to the ε-caprolactone derivative menthide. Using a diol initiator and controlled catalysis, menthide was polymerized to yield a low glass transition temperature telechelic polymer (PM) that was then further functionalized using the biomass-derived monomer lactide (LA) to yield fully renewable PLA