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Sample records for dicarboxylic acids part

  1. 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.

  2. 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.

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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.

  12. 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.

  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. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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).

  6. 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.

  7. 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.

  8. 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.

  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. 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

  12. 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.

  13. 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

  14. 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

  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. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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).

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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).

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. 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

  16. 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

  17. 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 ...

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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...

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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).

  1. 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

  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.

    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

  3. 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

  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. 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

  9. 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

  10. 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

  11. 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.

  12. 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 PAGESBeta

    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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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).

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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%.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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%.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. (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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. [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

  17. 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.

  18. 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

  19. [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.

  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. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. Plasma Amino Acid Concentrations in 108 Children Receiving a Pediatric Amino Acid Formulation as Part of Parenteral Nutrition

    PubMed Central

    Shelton, Chasity M.; Clark, Amanda J.; Storm, Michael C.; Helms, Richard A.

    2010-01-01

    BACKGROUND Plasma amino acid (PAA) levels can be largely normalized during parenteral nutrition (PN) in infants and children using a pediatric-specific amino acid (AA) formulation. However, these previous results were based on individual clinical studies of small populations of neonates and infants. OBJECTIVE We have now examined AA levels in 108 children (0–7 years of age) receiving a pediatric-specific AA formulation in PN using a single analytical methodology. METHODS Infants and children were enrolled in specific protocols and parents/caregivers gave informed consent. Patients were stable and receiving age-appropriate intakes of AA and non-protein calories. Samples were obtained between 8 and10 am, processed immediately, deproteinized, and AA concentrations (μmol/L) were determined on a Beckman 6300 analyzer. Means and SD were calculated for sub-populations stratified by age: 0–1 month (48 patients, n=139), 1–6 months (36 patients, n=124), 7–12 months (11 patients, n=41), and 1–7 years (13 patients, n=51). Z scores were calculated for each amino acid [(observed mean - normal control mean)/normal control SD]. RESULTS When compared to the neonatal reference range, nonessential AA had Z scores that ranged from −1.84 (asparagine) to +1.48 (threonine). Only plasma free cystine, free tyrosine, and phenylalanine had Z scores outside the −2.0 to +2.0 range (95% confidence limits). Plasma free cystine values were low in all groups except neonates. Free tyrosine levels were low in all groups despite the presence of N-acetyl-L-tyrosine in the pediatric AA formulation. Phenylalanine levels were elevated only in neonates. When children 1 to 7 years old were compared with an age-matched reference range, plasma free cystine values were low (Z score −2.47), as were plasma glutamine values (−3.11), but elevations were found in the dicarboxylic amino acids aspartic acid (+2.5) and glutamic acid (+4.27). Regardless of reference range used for comparison, all

  14. 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

  15. Polar organic marker compounds in atmospheric aerosol in the Po Valley during the Supersito campaigns - Part 1: Low molecular weight carboxylic acids in cold seasons

    NASA Astrophysics Data System (ADS)

    Pietrogrande, Maria Chiara; Bacco, Dimitri; Visentin, Marco; Ferrari, Silvia; Poluzzi, Vanes

    2014-04-01

    In the framework of the “Supersito” project, three intensive experimental campaigns were conducted in the Po Valley (Northern Italy) in cold seasons, such as late autumn, pre-winter and deep-winter, over three years from 2011 to 2013. As a part of a study on polar marker compounds, including carboxylic acids, sugar derivatives and lignin phenols, the present study reports a detailed discussion on the atmospheric concentrations of 14 low molecular weight carboxylic acids, mainly dicarboxylic and oxo-hydroxy carboxylic acids, as relevant markers of primary and secondary organic aerosols. PM2.5 samples were collected in two monitoring sites, representing urban and rural background stations. The total quantities of carboxylic acids were 262, 167 and 249 ng m-3 at the urban site and 308, 115, 248 ng m-3 at the rural site in pre-winter, fall and deep-winter, respectively. These high concentrations can be explained by the large human emission sources in the urbanized region, combined with the stagnant atmospheric conditions during the cold seasons that accumulate the organic precursors and accelerate the secondary atmospheric reactions. The distribution profiles of the investigated markers suggest the dominant contributions of primary anthropogenic sources, such as traffic, domestic heating and biomass burning. These results are confirmed by comparison with additional emission tracers, such as anhydro-saccharides for biomass burning and fatty acids originated from different anthropogenic sources. In addition, some secondary constituents were detected in both sites, as produced by in situ photo-chemical reactions from both biogenic (e.g. pinonic acid) and anthropogenic precursors (e.g. phthalic and adipic acids). The impact of different sources from human activities was elucidated by investigating the week pattern of carboxylic and fatty acid concentrations. The weekly trends of analytes during the warmer campaign (fall 2012; mean temperature: 12 °C) may be related to

  16. SnapShot: Nucleic acid immune sensors, part 2.

    PubMed

    Hornung, Veit

    2014-12-18

    The innate immune system has evolved sensors that can detect specific molecular fingerprints of non-self RNA or DNA. At the same time, some receptors respond to nucleic acids of both exogenous and endogenous origin, yet they are spatially segregated from endogenous nucleic acids. This SnapShot schematizes families and individual members of nucleic acid sensors with a focus on their ligands and the signaling pathways they employ.

  17. 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.

  18. 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.

  19. Chemistry in the Comics: Part 3. The Acidity of Paper.

    ERIC Educational Resources Information Center

    Carter, Henry A.

    1989-01-01

    This article focuses on the nature of acidity in pulp paper as found in comic books and library collections. Some of the various factors that contribute to the deterioration of paper are considered from a chemical perspective. (CW)

  20. 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

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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...

  7. 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...

  8. 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...

  9. [Polishing of titanium prosthetics (Part 6). The chemical polishing baths containing hydrofluoric acid and nitric acid].

    PubMed

    Tamaki, Y; Miyazaki, T; Suzuki, E; Miyaji, T

    1989-01-01

    Titanium was polished using several chemical polishing baths containing different ratios of hydrofluoric acid and nitric acid. The meltage, surface roughness, and surface texture of titanium samples after chemical polishing were affected by the ratio of hydrofluoric acid and nitric acid. Generally the meltage increased and surface roughness decreased when the mole concentration of hydrofluoric acid was high and that of nitric acid was low. For example the chemical polishing bath containing 5 mole hydrofluoric acid and 5 mole nitric acid improved the surface texture in one minute, but SEM observation revealed a partially rough surface caused by the excessive solution. The chemical polishing bath containing 1 mole hydrofluoric acid and 5 mole nitric acid did not improve the surface texture in a short time because of low solubility, but improved the surface texture gradually with the extension of the immersion time and a good surface texture was observed by SEM. The chemical polishing using the chemical polishing bath with low solubility and immersion of the prosthetics for a rather long time were considered useful procedures to obtain a smooth surface of titanium prosthetics while maintaining their accuracy.

  10. 40 CFR Appendix A to Part 434 - Alternate Storm Limitations for Acid or Ferruginous Mine Drainage

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Alternate Storm Limitations for Acid or Ferruginous Mine Drainage A Appendix A to Part 434 Protection of Environment ENVIRONMENTAL... Storm Limitations for Acid or Ferruginous Mine Drainage EC01MY92.113...

  11. 40 CFR Appendix A to Part 434 - Alternate Storm Limitations for Acid or Ferruginous Mine Drainage

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Alternate Storm Limitations for Acid or Ferruginous Mine Drainage A Appendix A to Part 434 Protection of Environment ENVIRONMENTAL...—Alternate Storm Limitations for Acid or Ferruginous Mine Drainage EC01MY92.113...

  12. 40 CFR Appendix A to Part 434 - Alternate Storm Limitations for Acid or Ferruginous Mine Drainage

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Alternate Storm Limitations for Acid or Ferruginous Mine Drainage A Appendix A to Part 434 Protection of Environment ENVIRONMENTAL... Storm Limitations for Acid or Ferruginous Mine Drainage EC01MY92.113...

  13. 40 CFR Appendix A to Part 434 - Alternate Storm Limitations for Acid or Ferruginous Mine Drainage

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Alternate Storm Limitations for Acid or Ferruginous Mine Drainage A Appendix A to Part 434 Protection of Environment ENVIRONMENTAL...—Alternate Storm Limitations for Acid or Ferruginous Mine Drainage EC01MY92.113...

  14. 40 CFR Appendix A to Part 434 - Alternate Storm Limitations for Acid or Ferruginous Mine Drainage

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Alternate Storm Limitations for Acid or Ferruginous Mine Drainage A Appendix A to Part 434 Protection of Environment ENVIRONMENTAL...—Alternate Storm Limitations for Acid or Ferruginous Mine Drainage EC01MY92.113...

  15. 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.

  16. Metabolism: Part II. The Tricarboxylic Acid (TCA), Citric Acid, or Krebs Cycle.

    ERIC Educational Resources Information Center

    Bodner, George M.

    1986-01-01

    Differentiates the tricarboxylic acid (TCA) cycle (or Krebs cycle) from glycolysis, and describes the bridge between the two as being the conversion of pyruvate into acetyl coenzyme A. Discusses the eight steps in the TCA cycle, the results of isotopic labeling experiments, and the net effects of the TCA cycle. (TW)

  17. [Practical diagnostics of acid-base disorders: part I: differentiation between respiratory and metabolic disturbances].

    PubMed

    Deetjen, P; Lichtwarck-Aschoff, M

    2012-11-01

    The first part of this overview on diagnostic tools for acid-base disorders focuses on basic knowledge for distinguishing between respiratory and metabolic causes of a particular disturbance. Rather than taking sides in the great transatlantic or traditional-modern debate on the best theoretical model for understanding acid-base physiology, this article tries to extract what is most relevant for everyday clinical practice from the three schools involved in these keen debates: the Copenhagen, the Boston and the Stewart schools. Each school is particularly strong in a specific diagnostic or therapeutic field. Appreciating these various strengths a unifying, simplified algorithm together with an acid-base calculator will be discussed.

  18. Fatty acid composition evaluation of edible parts of Eriocheir sinensis in intensive ponds of Gucheng waters.

    PubMed

    Yu, J Y; Yan, P S

    2015-01-01

    In Gucheng Lake, Jiangsu Province, China, randomly selected crabs were fed 2 diet types. Crab crude oil methyl ester analysis was performed using gas chromatography-mass spectrometry. Fatty acid compositions in the 3 edible parts of a crab - the hepatopancreas, gonad, and muscle - were analyzed. C16:1 and C18:2 were significantly higher in most commercial pellet feed-feeding crabs than in small trash fish-feeding crabs, while the opposite was observed for eicosapentaenoic and docosahexaenoic acids. Phytanic acid reached 1.93% in the hepatopancreas of small trash fish-feeding crabs. Furan fatty-acid-DiMe (11,5) contents in the testes of small trash fish-feeding crabs was 1.49%. These values were higher in male crabs than in female crabs. According to a standard ratio of 1:1:1 which meaning the saturated fathy acid (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) were 33.33 each, fatty acid structure analysis of crab edible parts showed that SFA:MUFA:PUFA of crab edible parts was 2.3-4.1:2.9-5.0:1.3-4.8. The highest muscle score was 29.53 in male trash fish-feeding crabs, and the lowest hepatopancreas score was -40.81 in female commercial pellet feed-feeding crabs. The n-6/n-3 ratio was 0.36-2.48. Muscle ratio was the lowest in female commercial pellet feed-feeding crabs. Thus, small trash fish-feeding and commercial pellet feed-feeding crabs are healthy foods. Overall, for consumption, the males of small trash fish-feeding crabs were better than the females, the muscle was better than the gonads and hepatopancreas, and the testis was better than the ovary. PMID:26125730

  19. 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.

  20. Atmospheric oxalic acid and related secondary organic aerosols in Qinghai Lake, a continental background site in Tibet Plateau

    NASA Astrophysics Data System (ADS)

    Meng, Jingjing; Wang, Gehui; Li, Jianjun; Cheng, Chunlei; Cao, Junji

    2013-11-01

    Summertime PM2.5 aerosols collected from Qinghai Lake (3200 m a.s.l.), a remote continental site in the northeastern part of Tibetan Plateau, were analyzed for dicarboxylic acids (C2-C11), ketocarboxylic acids and α-dicarbonyals. Oxalic acid (C2) is the dominant dicarboxylic acid in the samples, followed by malonic, succinic and azelaic acids. Total dicarboxylic acids (231 ± 119 ng m-3), ketocarboxylic acids (8.4 ± 4.3 ng m-3), and α-dicarbonyls (2.7 ± 2.1 ng m-3) at the Tibetan background site are 2-5 times less than those detected in lowland areas such as 14 Chinese megacities. Compared to those in other urban and marine areas enhancements in relative abundances of C2/total diacids and diacids-C/WSOC of the PM2.5 samples suggest that organic aerosols in the region are more oxidized due to strong solar radiation. Molecular compositions and air mass trajectories demonstrate that the above secondary organic aerosols in the Qinghai Lake atmosphere are largely derived from long-range transport. Ratios of oxalic acid, glyoxal and methylglyoxal to levoglucosan in PM2.5 aerosols emitted from household burning of yak dung, a major energy source for Tibetan in the region, are 30-400 times lower than those in the ambient air, which further indicates that primary emission from biomass burning is a negligible source of atmospheric oxalic acid and α-dicarbonyls at this background site.

  1. Costs of jasmonic acid induced defense in aboveground and belowground parts of corn (Zea mays L.).

    PubMed

    Feng, Yuanjiao; Wang, Jianwu; Luo, Shiming; Fan, Huizhi; Jin, Qiong

    2012-08-01

    Costs of jasmonic acid (JA) induced plant defense have gained increasing attention. In this study, JA was applied continuously to the aboveground (AG) or belowground (BG) parts, or AG plus BG parts of corn (Zea mays L.) to investigate whether JA exposure in one part of the plant would affect defense responses in another part, and whether or not JA induced defense would incur allocation costs. The results indicated that continuous JA application to AG parts systemically affected the quantities of defense chemicals in the roots, and vice versa. Quantities of DIMBOA and total amounts of phenolic compounds in leaves or roots generally increased 2 or 4 wk after the JA treatment to different plant parts. In the first 2 wk after application, the increase of defense chemicals in leaves and roots was accompanied by a significant decrease of root length, root surface area, and root biomass. Four weeks after the JA application, however, no such costs for the increase of defense chemicals in leaves and roots were detected. Instead, shoot biomass and root biomass increased. The results suggest that JA as a defense signal can be transferred from AG parts to BG parts of corn, and vice versa. Costs for induced defense elicited by continuous JA application were found in the early 2 wk, while distinct benefits were observed later, i.e., 4 wk after JA treatment.

  2. Costs of jasmonic acid induced defense in aboveground and belowground parts of corn (Zea mays L.).

    PubMed

    Feng, Yuanjiao; Wang, Jianwu; Luo, Shiming; Fan, Huizhi; Jin, Qiong

    2012-08-01

    Costs of jasmonic acid (JA) induced plant defense have gained increasing attention. In this study, JA was applied continuously to the aboveground (AG) or belowground (BG) parts, or AG plus BG parts of corn (Zea mays L.) to investigate whether JA exposure in one part of the plant would affect defense responses in another part, and whether or not JA induced defense would incur allocation costs. The results indicated that continuous JA application to AG parts systemically affected the quantities of defense chemicals in the roots, and vice versa. Quantities of DIMBOA and total amounts of phenolic compounds in leaves or roots generally increased 2 or 4 wk after the JA treatment to different plant parts. In the first 2 wk after application, the increase of defense chemicals in leaves and roots was accompanied by a significant decrease of root length, root surface area, and root biomass. Four weeks after the JA application, however, no such costs for the increase of defense chemicals in leaves and roots were detected. Instead, shoot biomass and root biomass increased. The results suggest that JA as a defense signal can be transferred from AG parts to BG parts of corn, and vice versa. Costs for induced defense elicited by continuous JA application were found in the early 2 wk, while distinct benefits were observed later, i.e., 4 wk after JA treatment. PMID:22744011

  3. Antioxidant capacity and fatty acid composition of different parts of Adenocarpus complicatus (Fabaceae) from Turkey.

    PubMed

    Berber, Adnan; Zengin, Gokhan; Aktumsek, Abdurrahman; Sanda, Murad Aydin; Uysal, Tuna

    2014-03-01

    Adenocarpus complicatus is distributed throughout the Anatolian peninsula and is widely used for human and animal nutrition. The purpose of this work was to study the antioxidant properties and fatty acid composition of different parts of this plant (fruits and mixed materials). The species was collected from Golyuzu village of the Seydisehir district near Konya province, Turkey. Fruit and mixed parts obtained from this species were ground and a 15g sample was used to prepare methanolic extracts. Powdered plant samples were extracted with 100mL methanol in a mechanical shaker. The obtained extracts were filtered and concentrated to dryness under reduced pressure and were subsequently stored at -20 degrees C. Antioxidant components, namely total phenolic and flavonoid content, were detected for each extract using spectrophotometric methods. Antioxidant capacity was evaluated by various assays including phosphomolybdenum, DPPH free radical scavenging capacity, metal chelating activity, and ferric and cupric ion reducing power. The fatty acid profiles of plant parts were also determined by using gas chromatography. The total phenolic content of fruit (36.21mgGAE/g) was higher than that of mixed materials (13.79mgGAE/g). The methanolic extract of mixed material had higher amounts of flavonoid than fruit extract. The free radical scavenging activity of extracts was expressed as IC50 value (microg/mL) (amount required to inhibit DPPH radical formation by 50%). The lower IC50 value reflects better free radical scavenging action. The radical scavenging activity of the samples was compared with BHT, it showed the mixed material to be almost two times more potent than the fruit extract. However, BHT is an excellent free radical scavenger with an IC50 of 34.061 microg/mL. The ferric and cupric reducing power potentials of the extracts were expressed as EC50 value (the effective concentration at which the absorbance was 0.5). Fruit extract exhibited strong ferric reducing

  4. Air pollution, acid rain, and the future of forests. Part 6. Looking beyond the forest

    SciTech Connect

    Postel, S.

    1984-12-01

    The emerging threat to the world's forests clearly raises the potential economic and ecological consequences of acid rain and air pollution. Because acid rain, ozone, and the buildup of carbon dioxide in the atmosphere are problems with a common origin, they can also have common solutions. Yet most existing and proposed strategies address isolated issues, rather than strive for the integrated solutions that are needed. Placing desulfurizing scrubbers on smokestacks, for example, will reduce sulfur dioxide and thereby control acid rain. But this technology will do nothing to help crops suffering from ozone, nothing to ensure that rain two decades from now will not be just as acidic from nitrogen oxides, and nothing to slow the rate at which carbon dioxide is increasing in the atmosphere. Technological controls for specific pollutants must be part of any plan to reduce emissions substantially in the immediate future. Yet funds are limited, and the time available for reversing these threatening trends grows ever shorter. These problems of common origin must be tackled simultaneously and at their core. Using energy more efficiently, recycling more paper and metals, and generating more power from alternative energy sources are rarely considered in strategies to reduce air pollution or acid rain. Yet they are among the most effective and least costly ways that exist.

  5. Spill behaviour using REACTPOOL. Part I. Results for accidental releases of chlorosulphonic acid (HSO(3)Cl).

    PubMed

    Kapias, T; Griffiths, R F

    2001-01-29

    Chlorosulphonic acid is a toxic, highly reactive and corrosive substance that exists in its liquid form at ambient conditions. Its major hazardous potential comes from the clouds of hydrogen chloride and sulphuric acid mist produced whenever this chemical escapes from containment and is exposed to moisture. It decomposes violently and sometimes explosively in the presence of water, liberating heat. On spillage it creates liquid pools that can either boil or evaporate. There are three sources of water available for reaction: free ground water, substrate water and atmospheric moisture. Hydrogen chloride gas or aqueous solution and sulphuric acid liquid are produced by the hydrolysis reaction. This paper describes the dangers involved in cases of accidental releases of chlorosulphonic acid, referring to its properties, toxicity data and mitigation tests. It also reports results of pool behaviour using REACTPOOL [T. Kapias, R.F. Griffiths, C. Stefanidis, J. Haz. Mat., submitted for publication]. These results indicate that the pool behaviour is governed mainly by the amount of water available for reaction. Surface roughness and wind speed also have a significant effect on the results. A discussion of the results in comparison with those for other water reactive substances is presented in Part III of this series of papers [T. Kapias, R.F. Griffiths, J. Haz. Mat., submitted for publication]. The generated cloud will initially contain chlorosulphonic acid, hydrogen chloride and sulphuric acid with numerous processes taking place. Initially, it is usually denser than air. Although chlorosulphonic acid has been involved in major hazard incidents, there are no experimental data relevant to the modelling requirements. Use of REACTPOOL provides insights into the major hazard role of this substance.

  6. Effect of acid pretreatment on different parts of corn stalk for second generation ethanol production.

    PubMed

    Li, Ping; Cai, Di; Luo, Zhangfeng; Qin, Peiyong; Chen, Changjing; Wang, Yong; Zhang, Changwei; Wang, Zheng; Tan, Tianwei

    2016-04-01

    In this study, the effects of different parts of corn stalk, including stem, leaf, flower, cob and husk on second generation ethanol production were evaluated. FTIR, XRD and SEM were performed to investigate the effect of dilute acid pretreatment. The bagasse obtained after pretreatment were further hydrolyzed by cellulase and used as the substrate for ethanol fermentation. As results, hemicelluloses fractions in different parts of corn stalk were dramatically removed and the solid fractions showed vivid compositions and crystallinities. Compared with other parts of corn stalk, the cob had higher sugar content and better enzymatic digestibility. The highest glucose yield of 94.2% and ethanol production of 24.0 g L(-1) were achieved when the cob was used as feedstock, while the glucose yield and the ethanol production were only 86.0% and 17.1 g L(-1) in the case of flower. PMID:26849200

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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).

  12. 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

  13. 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.

  14. 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

  15. Carbon honeycomb grids for advanced lead-acid batteries. Part III: Technology scale-up

    NASA Astrophysics Data System (ADS)

    Kirchev, A.; Serra, L.; Dumenil, S.; Brichard, G.; Alias, M.; Jammet, B.; Vinit, L.

    2015-12-01

    The carbon honeycomb grid technology employs new carbon/carbon composites with ordered 3D structure instead of the classic lead-acid battery current collectors. The technology is laboratory scaled up from small size grids corresponding to electrodes with a capacity of 3 Ah to current collectors suitable for assembly of lead-acid batteries covering the majority of the typical lead-acid battery applications. Two series of 150 grids each (one positive and one negative) are manufactured using low-cost lab-scale equipment. They are further subjected to pasting with active materials and the resulting battery plates are assembled in 12 V AGM-VLRA battery mono-blocks for laboratory testing and outdoor demonstration in electric scooter replacing its original VRLAB pack. The obtained results demonstrate that the technology can replace successfully the state of the art negative grids with considerable benefits. The use of the carbon honeycomb grids as positive plate current collectors is limited by the anodic corrosion of the entire structure attacking both the carbon/carbon composite part and the electroplated lead-tin alloy coating.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. DISTRIBUTION OF GLIAL FIBRILLARY ACIDIC PROTEIN IN DIFFERENT PARTS OF THE RAT BRAIN UNDER CADMIUM EXPOSURE.

    PubMed

    Kovalchuk, Yu P; Prischepa, I V; Si, U; Nedzvetsky, V S; Kot, Y G; Persky, E E; Ushakova, G A

    2015-01-01

    The chronic effects of low doses of cadmium on the distribution of soluble and filament forms of glial fibrillary acidic protein (GFAP) and their polypeptide fragments in different parts of the rat brain were investigated. Obtained results showed dose-dependent effect of cadmium on the soluble form of GFAP and more pronounced effect on the filament form and composition of the polypeptide fragments of the protein in the rat brain. Prolonged intoxication by cadmium ions in a dose of 1.0 μg/kg of body weight induced a significant decrease in soluble GFAP and an increase in the filament form in the rat brain, pointing to the development of reactive astrogliosis and the risk of neurodegeneration.

  1. Effect of Heat Sealing Temperature on Mechanical Properties and Molecular Structure at Heat-Sealed Parts of Polylactic Acid Film —Part II

    NASA Astrophysics Data System (ADS)

    Hashimoto, Yumi; Hashimoto, Yasuo; Tsujii, Tetsuya; Morimoto, Mitsuhiko; Kotaki, Masaya; Hamada, Hiroyuki

    Actual failure accidents of plastic bags often occur at the pin-hole and/or the crack, and also the edge that is just outside of the heat-sealed part becomes the failure initiation point. In this study, fracture mechanics tests and tear tests were performed to understand the resistance of heat-sealed parts and edge parts to introduced cracks. The fracture resistance and tear strength of the edge part was lower than that of the heat-sealed part, which was more obvious at higher heat sealing temperature. The optimum heat sealing temperature to obtain the balanced properties of heat-sealed polylactic acid (PLA) films was found to be 130°C.

  2. 40 CFR 174.507 - Nucleic acids that are part of a plant-incorporated protectant; exemption from the requirement of...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Nucleic acids that are part of a plant... PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.507 Nucleic acids that are part... nucleic acids that are part of a plant-incorporated protectant are exempt from the requirement of...

  3. 40 CFR 174.507 - Nucleic acids that are part of a plant-incorporated protectant; exemption from the requirement of...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Nucleic acids that are part of a plant... PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.507 Nucleic acids that are part... nucleic acids that are part of a plant-incorporated protectant are exempt from the requirement of...

  4. 40 CFR 174.507 - Nucleic acids that are part of a plant-incorporated protectant; exemption from the requirement of...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Nucleic acids that are part of a plant... PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.507 Nucleic acids that are part... nucleic acids that are part of a plant-incorporated protectant are exempt from the requirement of...

  5. 40 CFR 174.507 - Nucleic acids that are part of a plant-incorporated protectant; exemption from the requirement of...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Nucleic acids that are part of a plant... PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.507 Nucleic acids that are part... nucleic acids that are part of a plant-incorporated protectant are exempt from the requirement of...

  6. 40 CFR 174.507 - Nucleic acids that are part of a plant-incorporated protectant; exemption from the requirement of...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Nucleic acids that are part of a plant... PLANT-INCORPORATED PROTECTANTS Tolerances and Tolerance Exemptions § 174.507 Nucleic acids that are part... nucleic acids that are part of a plant-incorporated protectant are exempt from the requirement of...

  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. Fatty Acid Composition and Conjugated Linoleic Acid Content in Different Carcass parts of Dağlıç Lambs

    PubMed Central

    Karabacak, Ali; Boztepe, Saim

    2014-01-01

    This study was conducted to compare fatty acid composition and content of conjugated linoleic acid (CLA) in different regions of sheep carcasses. Lambs of the Dağlıç breed were used for this purpose. Subsequent to a 68-day period of intensive fattening, fatty acids were examined in samples taken from the legs, shoulders, breasts, and ribs of lamb carcasses. According to the analysis, in leg, shoulder, breast, and rib, respectively, total saturated fatty acids (SFA) were found to be 40.38, 42.69, 42.56, and 40.27%, unsaturated fatty acids (MUFA) were found to be 40.38, 44.17, 46.17, and 49.50%, polyunsaturated fatty acids (PUFA) were found to be 4.79, 4.29, 3.80, and 3.72%, and CLAs were found to be 1.49, 1.69, 1.53, and 1.59%. PMID:24523647

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Comparison of gamma-aminobutyric acid effects in different parts of the cat ileum.

    PubMed

    Pencheva, N; Itzev, D; Milanov, P

    1999-02-26

    The effects of gamma-aminobutyric acid (GABA) and those of a GABA(A) (muscimol) and a GABA(B) (baclofen) receptor agonists were determined on the spontaneous activity of longitudinally or circularly oriented preparations (segments) isolated from terminal, proximal and distal parts of the cat ileum. GABA applied at 1 microM to 2 mM caused dose-dependent biphasic changes (relaxation and contraction) in spontaneous activity of the longitudinal and circular layers in the terminal and distal parts of the cat ileum and monophasic changes (contraction) in the proximal part. The potency of GABA to elicit relaxant and/or contractile effects in different parts of the ileum showed a proximal-to-terminal increasing pattern. In the longitudinal layer of the distal and terminal ileum, muscimol (100 microM) mimicked the relaxation phase of the GABA effect, while baclofen (100 microM) simulated the contractile phase. Bicuculline, atropine and tetrodotoxin abolished GABA- and muscimol-induced relaxation and suppressed, but failed to prevent GABA- and baclofen-induced contractions. In addition, 2-hydroxysaclofen antagonized the baclofen-induced contractile effect, reduced the GABA-induced contractile phase but failed to prevent GABA- and muscimol-induced relaxation. In the circular layer of the same regions, muscimol mimicked the biphasic GABA effects, while baclofen was without effect. Bicuculline, atropine and tetrodotoxin completely prevented the GABA- and muscimol effects, while 2-hydroxysaclofen failed to antagonize them. In the longitudinal and circular layers of the proximal ileum, muscimol (100 microM) exerted a 'GABA-like' transient contractile effect, while baclofen (100 microM) did not elicit any response. Bicuculline, atropine and tetrodotoxin antagonized the GABA- and muscimol-induced contractile responses of longitudinal and circular layers, while 2-hydroxysaclofen was ineffective. The results suggested that the inhibitory and/or excitatory action of GABA on

  14. Lead-acid batteries in micro-hybrid applications. Part I. Selected key parameters

    NASA Astrophysics Data System (ADS)

    Schaeck, S.; Stoermer, A. O.; Kaiser, F.; Koehler, L.; Albers, J.; Kabza, H.

    Micro-hybrid electric vehicles were launched by BMW in March 2007. These are equipped with brake energy regeneration (BER) and the automatic start and stop function (ASSF) of the internal combustion engine. These functions are based on common 14 V series components and lead-acid (LA) batteries. The novelty is given by the intelligent onboard energy management, which upgrades the conventional electric system to the micro-hybrid power system (MHPS). In part I of this publication the key factors for the operation of LA batteries in the MHPS are discussed. Especially for BER one is high dynamic charge acceptance (DCA) for effective boost charging. Vehicle rest time is identified as a particular negative parameter for DCA. It can be refreshed by regular fully charging at elevated charge voltage. Thus, the batteries have to be outstandingly robust against overcharge and water loss. This can be accomplished for valve-regulated lead-acid (VRLA) batteries at least if they are mounted in the trunk. ASSF goes along with frequent high-rate loads for warm cranking. The internal resistance determines the drop of the power net voltage during cranking and is preferably low for reasons of power net stability even after years of operation. Investigations have to be done with aged 90 Ah VRLA-absorbent glass mat (AGM) batteries. Battery operation at partial state-of-charge gives a higher risk of deep discharging (overdischarging). Subsequent re-charging then is likely to lead to the formation of micro-short circuits in the absorbent glass mat separator.

  15. 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.

  16. Chemical structure of humic acids - Part 2, the molecular aggregation of some humic acid fractions in N, N-dimethylformamide

    USGS Publications Warehouse

    Wershaw, R. L.; Pinckney, D.J.

    1977-01-01

    Humic acid fractions form molecular aggregates in solution. In previous studies we have shown by small angle X-ray scattering that the size of these aggregates is a function of pH. In this study we have found that the size of the aggregates of two humic acid fractions in water and buffers and in dimethylformamide solutions can be changed by oxidation with molecular oxygen and air. These results cast new light on the bonding mechanisms that cause aggregation of the humic acid particles in solution. We have interpreted the changes in aggregation sizes as being brought about by changes in intermolecular and intramolecular hydrogen bonding of the humic particles. Solvation of the humic molecules by dimethylformamide interferes with some of the hydrogen bonding reactions between proton donor and acceptor groups on the same humic acid molecules or on different molecules.

  17. 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...

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Air pollution, acid rain, and the future of forests. Part 3. Counting the costs

    SciTech Connect

    Postel, S.

    1984-09-01

    Economic losses are predicted due to the effects of acid rain on forests in Europe and the United States. Growth declines and tree damage on forest lands intensively managed for marketable timber are described. Forest industries which produce paper and other forest products which consume large amounts of energy are said to be reluctant to support acid rain control measures. Few studies have examined the effects of acid deposition combined with intensive forestry practices.

  4. New cytotoxic triterpene acids from aboveground parts of Manihot esculenta from the Suriname rainforest.

    PubMed

    Chaturvedula, V S; Schilling, Jennifer K; Malone, Stan; Wisse, Jan H; Werkhoven, Marga C; Kingston, David G

    2003-03-01

    Two novel triterpene acids, esculentoic acid A ( 1) and B ( 2) as well as the seven known compounds 3 - 9 were isolated from an EtOAc extract of leaves, stems, and twigs of Manihot esculenta by bioassay-guided fractionation for cytotoxic activity. The structures of the two new compounds were established as 3alpha-hydroxytaraxer-14-en-29-oic acid ( 1) and 3-oxotaraxer-14-en-29-oic acid ( 2) on the basis of 1D and 2D NMR spectroscopic data interpretation and chemical conversions. The two new compounds 1 and 2 showed moderate cytotoxicity against the A2780 human ovarian cancer cell line.

  5. 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.

  6. Organic matter in sediments of an acidic mining lake as assessed by lipid analysis. Part I: fatty acids.

    PubMed

    Poerschmann, Juergen; Koschorreck, Matthias; Górecki, Tadeusz

    2012-01-01

    Fatty acid (FA) patterns of sediments collected from the bottom of an acidic mine pit lake (AML) at different depths (surface sediment: 0 to 1cm; deep sediment: 4 to 5 cm) were studied to characterize microbial communities and the sources of sedimentary organic matter (SOM). Studies were performed on the molecular level utilizing source-specific, diagnostic FA biomarkers. The biomarker-based approach has been used widely in marine sediment studies, but has not been applied for sediments from AMLs so far. Combined FA concentrations in the surface sediment were higher compared to those in the deep sediment (497 vs. 127 μg g(-1)d.w., respectively). This was related to deposition of autochthonous biomass and higher terrestrial plants onto the surface sediment, as well as--to lesser extent--with higher bacterial activity on the sediment-water interface. The FA distribution in both sediments was characterized by a strong even-over-odd preference and was bimodal in nature: there was a cluster at nC(14)-nC(18) characteristic of chiefly autochthonous (algal and bacterial) SOM production, and another cluster at nC(22-28) related to input from higher plants. The FA distribution in the surface sediment pointed to higher terrestrial input compared to autochthonous contribution to SOM (67%:33%) as an estimate. Fingerprinting of viable bacteria was accomplished through signature FA markers including branched C(15) and C(17) surrogates, cyclopropanoic acids, 3-hydroxy (OH) acids and monounsaturated surrogates with unusual double bond localization. The abundance of Gram-negative bacteria was higher in the surface sediment as evidenced by total diagnostic 3-OH-fatty acids (37 μg g(-1) versus 25 μg g(-1)). Potential source taxa in both sediment layers included acidophilic iron- and sulfur-oxidizing bacteria including Acidithiobacillus ferrooxidans. High abundances of terminally branched C(15) and C(17) surrogates in both sediments pointed to sulfate- and iron-reducing bacteria

  7. 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.

  8. Characterisation of calamansi (Citrus microcarpa). Part I: volatiles, aromatic profiles and phenolic acids in the peel.

    PubMed

    Cheong, Mun Wai; Chong, Zhi Soon; Liu, Shao Quan; Zhou, Weibiao; Curran, Philip; Bin Yu

    2012-09-15

    Volatile compounds in the peel of calamansi (Citrus microcarpa) from Malaysia, the Philippines and Vietnam were extracted with dichloromethane and hexane, and then analysed by gas chromatography-mass spectroscopy/flame ionisation detector. Seventy-nine compounds representing >98% of the volatiles were identified. Across the three geographical sources, a relatively small proportion of potent oxygenated compounds was significantly different, exemplified by the highest amount of methyl N-methylanthranilate in Malaysian calamansi peel. Principal component analysis and canonical discriminant analysis were applied to interpret the complex volatile compounds in the calamansi peel extracts, and to verify the discrimination among the different origins. In addition, four common hydroxycinnamic acids (caffeic, p-coumaric, ferulic and sinapic acids) were determined in the methanolic extracts of calamansi peel using ultra-fast liquid chromatography coupled to photodiode array detector. The Philippines calamansi peel contained the highest amount of total phenolic acids. In addition, p-Coumaric acid was the dominant free phenolic acids, whereas ferulic acid was the main bound phenolic acid.

  9. Intracellular pH modulates taste receptor cell volume and the phasic part of the chorda tympani response to acids.

    PubMed

    Lyall, Vijay; Pasley, Hampton; Phan, Tam-Hao T; Mummalaneni, Shobha; Heck, Gerard L; Vinnikova, Anna K; DeSimone, John A

    2006-01-01

    The relationship between cell volume and the neural response to acidic stimuli was investigated by simultaneous measurements of intracellular pH (pHi) and cell volume in polarized fungiform taste receptor cells (TRCs) using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) in vitro and by rat chorda tympani (CT) nerve recordings in vivo. CT responses to HCl and CO2 were recorded in the presence of 1 M mannitol and specific probes for filamentous (F) actin (phalloidin) and monomeric (G) actin (cytochalasin B) under lingual voltage clamp. Acidic stimuli reversibly decrease TRC pHi and cell volume. In isolated TRCs F-actin and G-actin were labeled with rhodamine phalloidin and bovine pancreatic deoxyribonuclease-1 conjugated with Alexa Fluor 488, respectively. A decrease in pHi shifted the equilibrium from F-actin to G-actin. Treatment with phalloidin or cytochalasin B attenuated the magnitude of the pHi-induced decrease in TRC volume. The phasic part of the CT response to HCl or CO2 was significantly decreased by preshrinking TRCs with hypertonic mannitol and lingual application of 1.2 mM phalloidin or 20 microM cytochalasin B with no effect on the tonic part of the CT response. In TRCs first treated with cytochalasin B, the decrease in the magnitude of the phasic response to acidic stimuli was reversed by phalloidin treatment. The pHi-induced decrease in TRC volume induced a flufenamic acid-sensitive nonselective basolateral cation conductance. Channel activity was enhanced at positive lingual clamp voltages. Lingual application of flufenamic acid decreased the magnitude of the phasic part of the CT response to HCl and CO2. Flufenamic acid and hypertonic mannitol were additive in inhibiting the phasic response. We conclude that a decrease in pHi induces TRC shrinkage through its effect on the actin cytoskeleton and activates a flufenamic acid-sensitive basolateral cation conductance that is involved in eliciting the phasic part of the CT response to

  10. 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

  11. 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.

  12. Binding of polyphenols to plant cell wall analogues - Part 2: Phenolic acids.

    PubMed

    Padayachee, A; Netzel, G; Netzel, M; Day, L; Zabaras, D; Mikkelsen, D; Gidley, M J

    2012-12-15

    Bacterial cellulose and cellulose-pectin composites were used as well-defined model plant cell wall (PCW) systems to study the interaction between phenolic acids (PA) derived from purple carrot juice concentrate (PCJC) and PCW components. Significant PA depletion from solution occurred, with pure cellulose initially (30s-1h) absorbing more than cellulose-pectin composites in the first hour (ca 20% cf 10-15%), but with all composites absorbing similar levels (ca 30%) after several days. Individual PAs bound to different relative extents with caffeic acid>chlorogenic acid>ferulic acid. Extrapolation of data for these model systems to carrot puree suggests that nutritionally-significant amounts of PAs could bind to cell walls, potentially restricting bioavailability in the small intestine and, as a consequence, delivering PAs to the large intestine for fermentation and metabolism by gut bacteria.

  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. Synthesis and metabotropic glutamate receptor activity of S-oxidized variants of (-)-4-amino-2-thiabicyclo-[3.1.0]hexane-4,6-dicarboxylate: identification of potent, selective, and orally bioavailable agonists for mGlu2/3 receptors.

    PubMed

    Monn, James A; Massey, Steven M; Valli, Matthew J; Henry, Steven S; Stephenson, Gregory A; Bures, Mark; Hérin, Marc; Catlow, John; Giera, Deborah; Wright, Rebecca A; Johnson, Bryan G; Andis, Sherri L; Kingston, Ann; Schoepp, Darryle D

    2007-01-25

    (-)-4-Amino-2-thiabicyclo-[3.1.0]hexane-4,6-dicarboxylate (LY389795, (-)-3) is a highly potent and selective agonist of metabotropic glutamate receptors 2 (mGlu2) and 3 (mGlu3). As part of our ongoing research program, we have prepared S-oxidized variants of (-)-3, compounds (-)-10, (+)-11 (LY404040), and (-)-12 (LY404039). Each of these chiral heterobicyclic amino acids displaced specific binding of the mGlu2/3 receptor antagonist 3H-2S-2-amino-2-(1S,2S-2-carboxycycloprop-1-yl)-3-(xanth-9-yl)propanoic acid (3H-LY341495) from membranes expressing recombinant human mGlu2 or mGlu3 and acted as potent agonists in cells expressing these receptor subtypes. Docking of the most potent of these derivatives, (+)-11, to mGlu2 revealed the possibility of an additional H-bond interaction between the sulfoxide oxygen of (+)-11 with tyrosine residue Y236. Pharmacokinetic analysis of mGlu active enantiomers (+)-11 and (-)-12 in rats showed each to be well absorbed following oral administration. Consistent with their mGlu2/3 agonist potency and pharmacokinetic properties, both (+)-11 and (-)-12 blocked phencyclidine-evoked ambulations in a dose-dependent manner, indicating their potential as nonclassical antipsychotic agents. PMID:17228865

  17. 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

  18. 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.

  19. Search for novel histone deacetylase inhibitors. Part II: design and synthesis of novel isoferulic acid derivatives.

    PubMed

    Lu, Wen; Wang, Fang; Zhang, Tao; Dong, Jinyun; Gao, Hongping; Su, Ping; Shi, Yaling; Zhang, Jie

    2014-05-01

    Previously, we described the discovery of potent ferulic acid-based histone deacetylase inhibitors (HDACIs) with halogeno-acetanilide as novel surface recognition moiety (SRM). In order to improve the affinity and activity of these HDACIs, twenty seven isoferulic acid derivatives were described herein. The majority of title compounds displayed potent HDAC inhibitory activity. In particular, IF5 and IF6 exhibited significant enzymatic inhibitory activities, with IC50 values of 0.73 ± 0.08 and 0.57 ± 0.16 μM, respectively. Furthermore, these compounds showed moderate antiproliferative activity against human cancer cells. Especially, IF6 displayed promising profile as an antitumor candidate with IC50 value of 3.91 ± 0.97 μM against HeLa cells. The results indicated that these isoferulic acid derivatives could serve as promising lead compounds for further optimization. PMID:24702857

  20. Chemical composition and antibacterial properties of essential oil and fatty acids of different parts of Ligularia persica Boiss

    PubMed Central

    Mohadjerani, Maryam; Hosseinzadeh, Rahman; Hosseini, Maryam

    2016-01-01

    Objective: The objective of this research was to investigate the chemical composition and antibacterial activities of the fatty acids and essential oil from various parts of Ligularia persica Boiss (L. persica) growing wild in north of Iran. Materials and Methods: Essential oils were extracted by using Clevenger-type apparatus. Antibacterial activity was tested on two Gram-positive and two Gram-negative bacteria by using micro dilution method. Results: GC and GC∕MS analysis of the oils resulted in detection of 94%, 96%, 93%, 99% of the total essential oil of flowers, stems, roots and leaves, respectively. The main components of flowers oil were cis-ocimene (15.4%), β-myrcene (4.4%), β-ocimene (3.9%), and γ-terpinene (5.0%). The major constituents of stems oil were β-phellandrene (5.4%), β-cymene (7.0%), valencene (3.9%). The main compounds of root oil were fukinanolid (17.0%), α-phellandrene (11.5%) and Β-selinene (5.0%) and in the case of leaves oil were cis-ocimene (4.8%), β-ocimene (4.9%), and linolenic acid methyl ester (4.7%). An analysis by GC-FID and GC-MS on the fatty-acid composition of the different parts of L. persica showed that major components were linoleic acid (11.3-31.6%), linolenic acid (4.7-21.8%) and palmitic acid (7.2-23.2%). Saturated fatty acids were found in lower amounts than unsaturated ones. The least minimum inhibition concentration (MIC) of the L. persica was 7.16 μg/ml against Pseudomonas aeruginosa. Conclusion: Our study indicated that the essential oil from L. persica stems and flowers showed high inhibitory effect on the Gram negative bacteria. The results also showed that fatty acids from the stems and leaves contained a high amount of poly-unsaturated fatty acids (PUFAs). PMID:27462560

  1. An Investigation of the Acid Rock Drainage Generation from the Road Cut Slope in the Middle Part of South Korea

    NASA Astrophysics Data System (ADS)

    Ji, S.; Cheong, Y.; Yim, G.

    2006-05-01

    To examine the Acid Rock Drainage (ARD) generation from the road cut slope, a prediction study including Acid-Base Accounting (ABA) test and Net Acid Generation (NAG) test was performed for road cut rock samples (20 samples) at the new construction site of a highway in the middle part of South Korea. This slope is composed of slate and phyllite. It was a pit wall which was operated as a quarry which produced materials for roofing. pH1:2 and EC1:2 measurements were performed to evaluate free hydrogen ion contents and salts in samples. ABA test was performed to estimate the balance of the acid generating minerals (mainly pyrite) and the acid neutralizing minerals (mainly carbonates) in rock samples. Total sulfur was analyzed by sulfur analyzer, and then the maximum potential acidity (MPA, kg H2SO4/t) was calculated. X-ray diffraction (XRD) analysis was performed to identify the mineral composition of rock samples. Acid neutralizing capacity (ANC) test, after the Sobek et al. (1978), was performed to estimate the amount of acid originated from the oxidation of sulfide minerals. NAPP (Net Acid Producing Potential) was calculated by total sulfur (MPA) and ANC. NAG test was performed with grounded samples and 15 % hydrogen peroxide, and then NAG was analyzed by measuring pH (NAGpH) of the mixed solution. pH1:2 and EC1:2 ranged from 2.95 to 7.23 and 17.1 to 3070.0 ¥ìS/cm, respectively. MPA of samples was ranged from 0.0 to 79.9 kg H2SO4/t. From the XRD analysis pyrite was found at the most samples. In the sample from highly weathered dike, goethite was found. Results of the ANC tests indicated that the value of ANC reached up to 59.36 kg H2SO4/t. Rock samples could be classified as Potential Acid Forming rock (PAF) and Non- Acid Forming rock (NAF) by plotting NAPP versus NAGpH. In this study 17 samples were classified as PAF rock. It means that this slope would generate ARD when they reacted with rain. Two samples were grouped as NAF. By application this ARD prediction

  2. Tribological properties of boric acid and boric acid forming surfaces: Part 1, Crystal chemistry and self-lubricating mechanism of boric acid

    SciTech Connect

    Erdemir, A.

    1990-01-01

    An in-depth understanding of the atomic-scale structure and chemistry of self-lubricating solids and how they relate to the efficiency and endurance of large-scale tribosystems is critically important. Of particular interest is the utilization of this understanding for the development of mechanistic models that can increase our ability to assess and predict the capabilities of self-lubricating solids. Accordingly, a comprehensive investigation was made of the crystal chemistry and self-lubrication mechanisms of boric acid and boric acid-forming surfaces. In this paper, the fundamentals of the crystal chemistry and the proposed lubrication mechanism of boric acid are described. Pin-on-disk tests performed on cold-pressed boric-acid pins and AISI 52100 steel disks, showed that the friction coefficient of this tribosystem is approximately 0.1. The results of this investigation indicate that boric acid, owing to its unique crystal structure and bond characteristics, is a promising solid lubricant for a wide range of tribological applications. 18 refs., 5 figs.

  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. Mechanism of hydrodenitrogenation low temperature oxygen chemisorption over acidic molybdenum catalysts: Part 7

    SciTech Connect

    Miranda, R.

    1991-01-01

    The low temperature oxygen chemisorption over acidic molybdena catalysts has evidenced the strong reducibility of near-surface Mo, and the effect of catalyst loading and support composition on such reducibility. It was determined that for supports with compositions under 50% silica, the optimum loading producing maximum surface reducibility is 8 wt% MoO{sub 3}, while for supports with more than 50% silica, the optimum loading is 4 wt% MoO{sub 3}. At this loading, a substantial portion of the support (containing acidic sites) is also exposed. The role of Lewis sites produced on the molybdena surface by coordinative unsaturation is the strong adsorption of aromatic or unsaturated amines, and the destabilization of C-C and C-N bonds. Hydrogenation and hydrogenolysis can then occur by H addition. The highly acidic Bronsted sites, present on the support as well as on the molybdena, strongly chemisorb the hydrogenated amines. The acidic sites contribute to denitrogenation by Hofmann elimination mechanism, as shown by the the abundance of unsaturated hydrocarbons produced, and are also active for cracking and cyclization, as shown by the selectivity towards methane and cyclopentene. 13 refs., 3 figs., 1 tab.

  6. Nutritional interventions to prevent and treat osteoarthritis. Part I: focus on fatty acids and macronutrients.

    PubMed

    Lopez, Hector L

    2012-05-01

    Osteoarthritis (OA) is the most common cause of musculoskeletal disability in elderly individuals, and it places an enormous economic burden on society. Management of OA is primarily focused on palliative relief by using agents such as nonsteroidal anti-inflammatory drugs and analgesics. However, such an approach is limited by a narrow therapeutic focus that fails to address the progressive and multimodal nature of OA. Given the favorable safety profile of most nutritional interventions, identifying disease-modifying nutritional agents capable of improving symptoms and also preventing, slowing, or even reversing the degenerative process in OA should remain an important paradigm in translational and clinical research. Applying advances in nutritional science to musculoskeletal medicine remains challenging, given the fluid and dynamic nature of the field, along with a rapidly developing regulatory climate over manufacturing and commerce requirements. The aim of this article is to review the available literature on effectiveness and potential mechanism of macronutrients for OA, with a focus on the following: long-chain ω-3 essential fatty acids eicosapentaenoic acid and docosahexaenoic acid, functional ω-6 fatty acid γ-linolenic acid, and macronutrient composition of background diet. There also is a discussion about the concept of rational polysupplementation via the strategic integration of multiple nutraceuticals with potential complementary mechanisms for improving outcomes in OA. As applied nutritional science evolves, it will be important to stay on the forefront of proteomics, metabolomics, epigenetics, and nutrigenomics, because they hold enormous potential for developing novel therapeutic and prognostic breakthroughs in many areas of medicine, including OA.

  7. Metabolic changes associated with tumor metastasis, part 2: Mitochondria, lipid and amino acid metabolism.

    PubMed

    Porporato, Paolo E; Payen, Valéry L; Baselet, Bjorn; Sonveaux, Pierre

    2016-04-01

    Metabolic alterations are a hallmark of cancer controlling tumor progression and metastasis. Among the various metabolic phenotypes encountered in tumors, this review focuses on the contributions of mitochondria, lipid and amino acid metabolism to the metastatic process. Tumor cells require functional mitochondria to grow, proliferate and metastasize, but shifts in mitochondrial activities confer pro-metastatic traits encompassing increased production of mitochondrial reactive oxygen species (mtROS), enhanced resistance to apoptosis and the increased or de novo production of metabolic intermediates of the TCA cycle behaving as oncometabolites, including succinate, fumarate, and D-2-hydroxyglutarate that control energy production, biosynthesis and the redox state. Lipid metabolism and the metabolism of amino acids, such as glutamine, glutamate and proline are also currently emerging as focal control points of cancer metastasis.

  8. Minimum chemical requirements for adhesin activity of the acid-stable part of Candida albicans cell wall phosphomannoprotein complex.

    PubMed

    Kanbe, T; Cutler, J E

    1998-12-01

    This study was conducted to define adhesive characteristics of the acid-stable moiety of the Candida albicans phosphomannoprotein complex (PMPC) on adherence of this fungus to marginal zone macrophages of the mouse spleen. Complete digestion of the acid-stable moiety (Fr.IIS) of the C. albicans PMPC with an alpha-mannosidase or hydrolysis with 0.6 N sulfuric acid destroyed adhesin activity, as determined by the inability of the soluble digests to inhibit yeast cell adherence to the splenic marginal zone. Fr.IIS adhesin activity was decreased following digestion with an alpha-1,2-specific mannosidase. Oligomannosyls consisting of one to six mannose units, which were isolated from the acid-stable part of the PMPC, did not inhibit yeast cell binding and thus do not function alone as adhesin sites in the PMPC. To gain more insight into the minimum requirements for adhesin activity, PMPCs were isolated from a Saccharomyces cerevisiae wild-type strain and from mutant strains mnn1, mnn2, and mnn4; the PMPCs were designated scwt/Fr.II, scmn1/Fr.II, scmn2/Fr.II, and scmn4/Fr.II, respectively. S. cerevisiae scmn2/Fr.II lacks oligomannosyl side chain branches from the outer core mannan, and scmn2/Fr.II was the only PMPC without adhesin activity. S. cerevisiae scwt/Fr.II, scmn1/Fr.II, and scmn4/Fr.II showed adhesin activities less than that of C. albicans Fr.II. These three S. cerevisiae PMPCs are generally similar to Fr. IIS, except that the S. cerevisiae structure has fewer and shorter side chains. Immunofluorescence microscopy show that the acid-stable part of the PMPC is displayed homogeneously on the C. albicans yeast cell surface, which would be expected for a surface adhesin. Our results indicate that both the mannan core and the oligomannosyl side chains are responsible for the adhesin activity of the acid-stable part of the PMPC. PMID:9826359

  9. Hydrometallurgical process for zinc recovery from electric arc furnace dust (EAFD): part I: Characterization and leaching by diluted sulphuric acid.

    PubMed

    Oustadakis, P; Tsakiridis, P E; Katsiapi, A; Agatzini-Leonardou, S

    2010-07-15

    The present paper is the first of a series of two articles dealing with the development of an integrated process for the recovery of zinc from electric arc furnace dust (EAFD), a hazardous industrial waste generated in the collection of particulate material during steelmaking process via electric arc furnace. Part I presents the EAFD characterization and its leaching process by diluted sulphuric acid, whereas Part II deals with the purification of the leach liquor and the recovery of zinc by solvent extraction/electrowinning. The characterization of the examined electric arc furnace dust was carried out by using granulometry analysis, chemical analysis, X-ray diffraction (XRD), thermogravimetric/differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The leaching process was based on the Zn extraction with diluted sulphuric acid from EAFD under atmospheric conditions and without using any preliminary treatment. Statistical design and analysis of experiments were used, in order to determine the main effects and interactions of the leaching process factors, which were: acid normality, temperature and solid to liquid ratio. The zinc recovery efficiency on the basis of EAFD weight reached 80%. X-ray diffraction and scanning electron microscopy were used for the characterization of the leached residues. PMID:20129730

  10. Hydrometallurgical process for zinc recovery from electric arc furnace dust (EAFD): part I: Characterization and leaching by diluted sulphuric acid.

    PubMed

    Oustadakis, P; Tsakiridis, P E; Katsiapi, A; Agatzini-Leonardou, S

    2010-07-15

    The present paper is the first of a series of two articles dealing with the development of an integrated process for the recovery of zinc from electric arc furnace dust (EAFD), a hazardous industrial waste generated in the collection of particulate material during steelmaking process via electric arc furnace. Part I presents the EAFD characterization and its leaching process by diluted sulphuric acid, whereas Part II deals with the purification of the leach liquor and the recovery of zinc by solvent extraction/electrowinning. The characterization of the examined electric arc furnace dust was carried out by using granulometry analysis, chemical analysis, X-ray diffraction (XRD), thermogravimetric/differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The leaching process was based on the Zn extraction with diluted sulphuric acid from EAFD under atmospheric conditions and without using any preliminary treatment. Statistical design and analysis of experiments were used, in order to determine the main effects and interactions of the leaching process factors, which were: acid normality, temperature and solid to liquid ratio. The zinc recovery efficiency on the basis of EAFD weight reached 80%. X-ray diffraction and scanning electron microscopy were used for the characterization of the leached residues.

  11. Stearic acid induces proinflammatory cytokine production partly through activation of lactate-HIF1α pathway in chondrocytes.

    PubMed

    Miao, Hongming; Chen, Liang; Hao, Lijun; Zhang, Xuan; Chen, Yujuan; Ruan, Zhihua; Liang, Houjie

    2015-01-01

    The biomechanics stress and chronic inflammation in obesity are causally linked to osteoarthritis. However, the metabolic factors mediating obesity-related osteoarthritis are still obscure. Here we scanned and identified at least two elevated metabolites (stearic acid and lactate) from the plasma of diet-induced obese mice. We found that stearic acid potentiated LDH-a-dependent production of lactate, which further stabilized HIF1α protein and increased VEGF and proinflammatory cytokine expression in primary mouse chondrocytes. Treatment with LDH-a and HIF1α inhibitors notably attenuated stearic acid-or high fat diet-stimulated proinflammatory cytokine production in vitro and in vivo. Furthermore, positive correlation of plasma lactate, cartilage HIF1α and cytokine levels with the body mass index was observed in subjects with osteoarthritis. In conclusion, saturated free fatty acid induced proinflammatory cytokine production partly through activation of a novel lactate-HIF1α pathway in chondrocytes. Our findings hold promise of developing novel clinical strategies for the management of obesity-related diseases such as osteoarthritis.

  12. Spectroscopic studies of alumina-supported nickel catalysts precursors. Part I. Catalysts prepared from acidic solutions

    NASA Astrophysics Data System (ADS)

    Pasieczna-Patkowska, S.; Ryczkowski, J.

    2007-04-01

    Nickel alumina-supported catalysts were prepared from acidic solutions of nickel nitrate by the CIM and DIM methods (classical and double impregnation, respectively). The catalysts exhibited different nickel species due to the existence of various metal-support interaction strengths. As a consequence, the reducibility and other surface properties changed as a function of the preparation method. The aim of this work was to study the interaction between the metal precursor and the alumina surface by means of FT-IR (Fourier transform infrared) and FT-IR/PAS (FT-IR photoacoustic spectroscopy).

  13. Poly(lactic acid)/natural rubber/cellulose nanocrystal bionanocomposites part I. Processing and morphology.

    PubMed

    Bitinis, Natacha; Verdejo, Raquel; Bras, Julien; Fortunati, Elena; Kenny, Jose Maria; Torre, Luigi; López-Manchado, Miguel Angel

    2013-07-25

    PLA/NR/cellulose nanowhisker composites were prepared using three types of cellulose nanocrystals (CNC), i.e. unmodified CNC obtained from acid hydrolysis of microcrystalline cellulose and two surface modified CNC. The two modification reactions, consisting on the grafting of long alkyl chains and of PLA chains onto the cellulose nanocrystals were carried out in order to facilitate the incorporation of the nanocrystals in the PLA/NR blend. A novel processing method was optimized combining solvent casting and extrusion in order to obtain a homogeneous dispersion of the nanofillers in the blend. The CNC modifications determined their location in the PLA/NR blend and influenced its morphology. PMID:23768607

  14. New surface viscometer of high sensitivity. Part 3. Stearic acid at the oil/water interface

    SciTech Connect

    Goodrich, F.C.; Goupil, D.W.

    1980-06-01

    Work with the knife-in-wall surface shear viscometer is continued using the oil/water interface. The viscometer is useful for studies at liquid/liquid interfaces and also is a valuable tool in investigating the interfacial structure of adsorbed films. When used in conjunction with interfacial tension measurements, it can greatly elucidate the physical condition of an interface. Stearic acid adsorbed from cyclohexane to the cyclohexane/aqueous NaCl interface responds rheologically in dramatic fashion when changes are made in the pH of the aqueous phase of the temperature of the system. Starting at an interfacial viscosity of 5 X 10/sup -4/ surface poise at pH 5.5, etao/w increases to greater than 10/sup -1/ surface poise at the point of maximum surface concentration (pH 9.0). Increasing the pH beyond 9.0 causes the stearic acid to dissolve into the aqueous phase and drastically reduces the interfacial viscosity. The interfacial tension reflects the changes in the interface. At pH 9.0, the interface experiences a phase change as the temperature is raised from T = 21.5 C to T = 21.9 C. 31 references.

  15. Particulates in hydrometallurgy: Part III. Dewatering behavior of flocculated laterite acid leach residues

    NASA Astrophysics Data System (ADS)

    Briceno, A.; Osseo-Asare, K.

    1995-02-01

    Three polyacrylamide-based polymers of different chemical properties (polymer A, 34 pct anionic, 11×106 mol wt; polymer B, 7 pct anionic, 7.5×106 mol wt; polymer C, nonionic, 13.5×106 mol wt) were used to evaluate the flocculation behavior of laterite acid leach residues. The solid-liquid separation characteristics of the leach residues were investigated with the aid of settling rate, supernatant turbidity, and slurry filtrability measurements. The polymeric flocculants were found to be effective in improving the dewatering properties of the acid leach residues. Polymer effectiveness increased with increasing polymer dosage for all the polymers, but an optimum polymer dose was only found for polymer A (34 pct anionic, 11×106 mol wt) in the studied range of polymer addition. Similarly, the dewatering behavior was improved at higher polymer molecular weight. In addition, it was found that the flocculation performance was adversely affected by an increase in the degree of polymer hydrolysis which, in turn, increases the ratio of carboxylic to amide functional groups in the polymer chain. Polymer C (nonionic ˜0 pct hydrolysis, 13.5×106 mol wt) was found to be the most efficient flocculant in terms of all the performance criteria investigated. The preceding results were rationalized in terms of bridging flocculation, the ionization and molecular configuration of the polymers, hydrogen bonding, and the solid/aqueous interfacial charge.

  16. Phospholipid fatty acid analysis as part of the Yucca Mountain Project. Final report

    SciTech Connect

    Ringelberg, D.B.; White, D.C.

    1996-09-01

    In support of the Yucca Mountain subsurface microbial characterization project phospholipid fatty acid (PLFA) analyses for viable microbial biomass, community composition and nutritional status were performed. Results showed a positive correlation between a decrease in viable biomass and increase in depth with the lowest biomass values being obtained from the Topopah Spring geologic horizon. A plot of the ratio of non-viable (diglyceride fatty acids) to viable (PLFA) cells also showed the lowest values to derive from the Topopah Spring horizon. Estimations of microbial community composition, made from the patterns of PLFA recovered from the sediment samples, revealed similarities between samples collected within the same geologic horizons: Tiva Canyon, Pre-Pah Canyon and Topopah Spring. Results indicated the presence of mixed communities composed of gram positive, gram negative, actinomycete and obligate anaerobic bacteria. Culturable organisms, recovered from similar sediments, were representative of the same bacterial classifications although gram positive bacterial isolates typically outnumbered gram negative isolates. Within the gram negative bacterial community, corroborative indicators of physiological stress were apparent in the Topopah Spring horizon.

  17. Root-uptake of (14)C derived from acetic acid and (14)C transfer to rice edible parts.

    PubMed

    Ogiyama, Shinichi; Suzuki, Hiroyuki; Inubushi, Kazuyuki; Takeda, Hiroshi; Uchida, Shigeo

    2010-02-01

    Three types of culture experiments using paddy rice (Oryza sativa L.) were performed to examine root-uptake of (14)C in the form of acetic acid: double pot experiment (hydroponics), wet culture experiment (submerged sand medium), and chamber experiment (hydroponics and submerged sand medium). The (14)C radioactivity in the plant, mediums, and atmospheric carbon dioxide ((14)CO(2)) in the chamber were determined, and the distribution of (14)C in the plant was visualized using autoradiography. In the double pot experiment, the shoot of the plant and the lower root which was soaked in the culture solution had (14)C radioactivity, but the upper root which did not have contact with the solution had none. There were also (14)C radioactivity in the grains and roots in the wet culture experiment. Results of the chamber experiment showed that (14)CO(2) gas was released from the culture solution in both types of cultures. Results indicated that the (14)C-acetic acid absorbed by rice plant through its root would be very small. Most of the (14)C-acetic acid was transformed into gaseous forms either in the culture solution or rhizosphere. A relatively longer time would be needed to assimilate (14)C derived from acetic acid to grain parts after it was once absorbed by the shoot through the root. Availability of (14)C for the plant in sand culture was considered to be decreased compared with that for the plant in the hydroponics experiment. It was suggested that rice plant absorbed and assimilated (14)C through the plant roots not because of uptake of (14)C-acetic acid but because of uptake of (14)C in gaseous forms such as (14)CO(2). PMID:19962904

  18. HPLC simultaneous determination of arbutin, chlorogenic acid and 6'-O-caffeoylarbutin in different parts of Vaccinium dunalianum Wight.

    PubMed

    Luo, Xu-Lu; Li, Na; Xu, Min; Zhu, Hong-Tao; He, Peng; Ding, Yong; Zhao, Ping; Zhang, Ying-Jun

    2015-01-01

    Arbutin (1), chlorogenic acid (2) and 6'-O-caffeoylarbutin (3) are three major components in Vaccinium dunalianum Wight with various promising bioactivities. A reliable, reproducible and accurate method for simultaneous and quantitative determination of 1-3 is developed by RP-HPLC analysis. This method should be appropriate for the quality assurance of unprocessed and processed materials of V. dunalianum. The contents of 1-3 in different parts of V. dunalianum from different origins were analysed. The content of 3 was much higher than those of 1 and 2, accounting for up to 31.76% in the dried leaf buds. Moreover, the leaf buds, flower buds and leaves showed a tendency towards higher contents of 1-3 than the other plant parts.

  19. Organic Analysis in the Miller Range 090657 CR2 Chondrite: Part 2 Amino Acid Analyses

    NASA Technical Reports Server (NTRS)

    Burton, A. S.; Cao, T.; Nakamura-Messenger, K.; Berger, E. L.; Messenger, S.; Clemett, S. J.; Aponte, J. C.; Elsila, J. E.

    2016-01-01

    Primitive carbonaceous chondrites contain a wide variety of organic material, ranging from soluble discrete molecules to insoluble, unstructured kerogen-like components, as well as structured nano-globules of macromolecular carbon. The relationship between the soluble organic molecules, macromolecular organic material, and host minerals are poorly understood. Due to the differences in extractability of soluble and insoluble organic materials, the analysis methods for each differ and are often performed independently. The combination of soluble and insoluble analyses, when performed concurrently, can provide a wider understanding of spatial distribution, and elemental, structural and isotopic composition of organic material in primitive meteorites. Using macroscale extraction and analysis techniques in combination with in situ microscale observation, we have been studying both insoluble and soluble organic material in the primitive CR2 chondrite Miller Range (MIL) 090657. In accompanying abstracts (Cao et al. and Messenger et al.) we discuss insoluble organic material in the samples. By performing the consortium studies, we aim to improve our understanding of the relationship between the meteorite minerals and the soluble and insoluble organic phases and to delineate which species formed within the meteorite and those that formed in nebular or presolar environments. In this abstract, we present the results of amino acid analyses of MIL 090657 by ultra performance liquid chromatography with fluorescence detection and quadrupole-time of flight mass spectrometry. Amino acids are of interest because they are essential to life on Earth, and because they are present in sufficient structural, enantiomeric and isotopic diversity to allow insights into early solar system chemical processes. Furthermore, these are among the most isotopically anomalous species, yet at least some fraction are thought to have formed by aqueously-mediated processes during parent body alteration.

  20. 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.

  1. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study

    SciTech Connect

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-15

    Highlights: • Two scenarios of acid gases removal in WTE plants were compared in an LCA study. • A detailed inventory based on primary data has been reported for the production of the new dolomitic sorbent. • Results show that the comparison between the two scenarios does not show systematic differences. • The potential impacts are reduced only if there is an increase in the energy efficiency of the WTE plant. - Abstract: The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO{sub 2} emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in

  2. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-01

    The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO2 emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in Biganzoli et al. (2014) and from the dolomitic sorbent production plant. The results of the LCA show minor changes in the potential impacts between the two operational modes of the plants. These differences are for 8 impact categories in favour of the new operational mode based on the addition of the dolomitic sorbent, and for 7 impact categories in favour of the traditional operation. A final evaluation was conducted on the potential

  3. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-01

    The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO2 emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in Biganzoli et al. (2014) and from the dolomitic sorbent production plant. The results of the LCA show minor changes in the potential impacts between the two operational modes of the plants. These differences are for 8 impact categories in favour of the new operational mode based on the addition of the dolomitic sorbent, and for 7 impact categories in favour of the traditional operation. A final evaluation was conducted on the potential

  4. Carbon honeycomb grids for advanced lead-acid batteries. Part II: Operation of the negative plates

    NASA Astrophysics Data System (ADS)

    Kirchev, A.; Dumenil, S.; Alias, M.; Christin, R.; de Mascarel, A.; Perrin, M.

    2015-04-01

    The article presents the recent progress in the carbon honeycomb grid technology for valve-regulated lead-acid batteries with absorptive glass-mat separators (AGM-VRLAB). The work is focused on the development of negative current collectors using industrial grade composite honeycomb precursors. The developed model AGM-VRLA cells comprised of one prototype honeycomb negative electrode and two conventional traction positive counter-electrodes show high utilisation of the negative active material and long cycle life both in high-rate partial state of charge (HRPSoC) cycling mode and in deep cycling mode. The analysis of the results from the cycle-life tests and the tear-down analysis indicate that the benefits delivered by the novel grids can be related to the low mesh size of the grid, low γ-coefficient, as well as the use of milled carbon fibre additive. The combination of the three, results in the reversibility of the negative active material sulfation process when the electrolyte concentration in the cells is lower than the one traditionally used in the AGM-VRLAB technology. The negative plates show no signs of irreversible degradation after more than 900 cycles in deep cycling mode and more than 2000 capacity turnovers (equivalent cycles) in HRPSoC cycling mode.

  5. Free fatty acid particles in protein formulations, part 2: contribution of polysorbate raw material.

    PubMed

    Siska, Christine C; Pierini, Christopher J; Lau, Hollis R; Latypov, Ramil F; Fesinmeyer, R Matthew; Litowski, Jennifer R

    2015-02-01

    Polysorbate 20 (PS20) is a nonionic surfactant frequently used to stabilize protein biopharmaceuticals. During the development of mAb formulations containing PS20, small clouds of particles were observed in solutions stored in vials. The degree of particle formation was dependent on PS20 concentration. The particles were characterized by reversed-phase HPLC after dissolution and labeling with the fluorescent dye 1-pyrenyldiazomethane. The analysis showed that the particles consisted of free fatty acids (FFAs), with the distribution of types consistent with those found in the PS20 raw material. Protein solutions formulated with polysorbate 80, a chemically similar nonionic surfactant, showed a substantial delay in particle formation over time compared with PS20. Multiple lots of polysorbates were evaluated for FFA levels, each exhibiting differences based on polysorbate type and lot. Polysorbates purchased in more recent years show a greater distribution and quantity of FFA and also a greater propensity to form particles. This work shows that the quality control of polysorbate raw materials could play an important role in biopharmaceutical product quality.

  6. Heterogeneous Formation of Polar Stratospheric Clouds- Part 1: Nucleation of Nitric Acid Trihydrate (NAT)

    NASA Technical Reports Server (NTRS)

    Hoyle, C. R.; Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Grooss, J.-U.; Peter, T.

    2013-01-01

    Satellite-based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current understanding, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid-December 2009, a heterogeneous nucleation mechanism is required, occurring via immersion freezing on the surface of solid particles, likely of meteoritic origin. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along more than sixty thousand trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) observation points. Comparing the optical properties of the modelled NAT with these observations enabled a thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory, is simple to implement in models and provides substantial advantages over previous approaches which involved a constant rate of NAT nucleation in a given volume of air. It is shown that the new method is capable of reproducing observed polar stratospheric clouds (PSCs) very well, despite the varied conditions experienced by air parcels travelling along the different trajectories. In a companion paper, ZOMM is applied to a later period of the winter, when ice PSCs are also present, and it is shown that the observed PSCs are also represented extremely well under these conditions.

  7. 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.

  8. 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.

  9. Tribological properties of boric acid and boric-acid-forming surfaces: Part 2, Formation and self-lubrication mechanisms of boric acid films on boron- and boric-oxide-containing surfaces

    SciTech Connect

    Erdemir, A.; Fenske, G.R.; Erck, R.A.; Nichols, F.A.; Busch, D.

    1990-01-01

    This paper describes the formation and self-lubricating mechanisms of boric acid films on boron- and boric oxide-containing surfaces. As reported in part I, boric acid, owing to a layered triclinic crystal structure and weak interlayer bonds, enjoys an unusual lubrication capability. RF-magnetron sputtering and vacuum evaporation techniques were used to produce thin coatings of boron and boric oxides on steel substrates. The results of tribological experiments indicate that the room temperature friction coefficient of tribosystems that include boron and/or boric oxide coatings ranges from 0.05 to 0.07, depending on the coating type. Laser-Raman spectroscopy of these surfaces revealed that this low friction is associated with a thin boric acid film that forms on the surfaces of these coatings. The fabrication and potential importance of boric acid and boric acid-forming surfaces for practical applications are enumerated. Surface engineering of tribomaterials, such as these demonstrated in this paper, is suggested as a new lubrication concept for use in present and future tribological industries. 16 refs.

  10. 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.

  11. Site-Specifically Labeled Immunoconjugates for Molecular Imaging--Part 2: Peptide Tags and Unnatural Amino Acids.

    PubMed

    Adumeau, Pierre; Sharma, Sai Kiran; Brent, Colleen; Zeglis, Brian M

    2016-04-01

    Molecular imaging using radioisotope- or fluorophore-labeled antibodies is increasingly becoming a critical component of modern precision medicine. Yet despite this promise, the vast majority of these immunoconjugates are synthesized via the random coupling of amine-reactive bifunctional probes to lysines within the antibody, a process that can result in heterogeneous and poorly defined constructs with suboptimal pharmacological properties. In an effort to circumvent these issues, the last 5 years have played witness to a great deal of research focused on the creation of effective strategies for the site-specific attachment of payloads to antibodies. These chemoselective modification methods yield immunoconjugates that are more homogenous and better defined than constructs created using traditional synthetic approaches. Moreover, site-specifically labeled immunoconjugates have also been shown to exhibit superior in vivo behavior compared to their randomly modified cousins. The over-arching goal of this two-part review is to provide a broad yet detailed account of the various site-specific bioconjugation approaches that have been used to create immunoconjugates for positron emission tomography (PET), single photon emission computed tomography (SPECT), and fluorescence imaging. In Part 1, we covered site-specific bioconjugation techniques based on the modification of cysteine residues and the chemoenzymatic manipulation of glycans. In Part 2, we will detail two families of bioconjugation approaches that leverage biochemical tools to achieve site-specificity. First, we will discuss modification methods that employ peptide tags either as sites for enzyme-catalyzed ligations or as radiometal coordination architectures. And second, we will examine bioconjugation strategies predicated on the incorporation of unnatural or non-canonical amino acids into antibodies via genetic engineering. Finally, we will compare the advantages and disadvantages of the modification

  12. Site-Specifically Labeled Immunoconjugates for Molecular Imaging—Part 2: Peptide Tags and Unnatural Amino Acids

    PubMed Central

    Adumeau, Pierre; Sharma, Sai Kiran; Brent, Colleen; Zeglis, Brian M.

    2016-01-01

    Molecular imaging using radioisotope- or fluorophore-labeled antibodies is increasingly becoming a critical component of modern precision medicine. Yet despite this promise, the vast majority of these immunoconjugates are synthesized via the random coupling of amine-reactive bifunctional probes to lysines within the antibody, a process that can result in heterogeneous and poorly defined constructs with suboptimal pharmacological properties. In an effort to circumvent these issues, the last 5 years have played witness to a great deal of research focused on the creation of effective strategies for the site-specific attachment of payloads to antibodies. These chemoselective modification methods yield immunoconjugates that are more homogenous and better defined than constructs created using traditional synthetic approaches. Moreover, site-specifically labeled immunoconjugates have also been shown to exhibit superior in vivo behavior compared to their randomly modified cousins. The over-arching goal of this two-part review is to provide a broad yet detailed account of the various site-specific bioconjugation approaches that have been used to create immunoconjugates for positron emission tomography (PET), single photon emission computed tomography (SPECT), and fluorescence imaging. In Part 1, we covered site-specific bioconjugation techniques based on the modification of cysteine residues and the chemoenzymatic manipulation of glycans. In Part 2, we will detail two families of bioconjugation approaches that leverage biochemical tools to achieve site-specificity. First, we will discuss modification methods that employ peptide tags either as sites for enzyme-catalyzed ligations or as radiometal coordination architectures. And second, we will examine bioconjugation strategies predicated on the incorporation of unnatural or non-canonical amino acids into antibodies via genetic engineering. Finally, we will compare the advantages and disadvantages of the modification

  13. Defensive strategies in Geranium sylvaticum, Part 2: Roles of water-soluble tannins, flavonoids and phenolic acids against natural enemies.

    PubMed

    Tuominen, Anu

    2013-11-01

    Geranium sylvaticum is a common herbaceous plant in Fennoscandia, which has a unique phenolic composition. Ellagitannins, proanthocyanidins, galloylglucoses, gallotannins, galloyl quinic acids and flavonoids possess variable distribution in its different organs. These phenolic compounds are thought to have an important role in plant-herbivore interactions. The aim of this study was to quantify these different water-soluble phenolic compounds and measure the biological activity of the eight organs of G. sylvaticum. Compounds were characterized and quantified using HPLC-DAD/MS, in addition, total proanthocyanidins were determined by BuOH-HCl assay and total phenolics by the Folin-Ciocalteau method. Two in vitro biological activity measurements were used: the prooxidant activity was measured by the browning assay and antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Organ extracts were fractionated using column chromatography on Sephadex LH-20 and the activities of fractions was similarly measured to evaluate which polyphenol groups contributed the most to the biological activity of each organ. The data on the activity of fractions were examined by multivariate data analysis. The water-soluble extracts of leaves and pistils, which contained over 30% of the dry weight as ellagitannins, showed the highest pro-oxidant activity among the organ extracts. Fraction analysis revealed that flavonoids and galloyl quinic acids also exhibited high pro-oxidant activity. In contrast, the most antioxidant active organ extracts were those of the main roots and hairy roots that contained high amounts of proanthocyanidins in addition to ellagitannins. Analysis of the fractions showed that especially ellagitannins and galloyl quinic acids have high antioxidant activity. We conclude that G. sylvaticum allocates a significant amount of tannins in those plant parts that are important to the fitness of the plant and susceptible to natural enemies, i

  14. Supramolecular assemblies of 4,7-phenanthroline with various aromatic polycarboxylic acids

    NASA Astrophysics Data System (ADS)

    Biswas, Sharmita Nandy; Nandy, Purnendu

    2016-10-01

    Five molecular complexes 1a-1e, of 4,7-phenanthroline (1) with various aromatic polycarboxylic acids such as benzene-1,3-dicarboxylic acid (a), pyridine-2,6-dicarboxylic acid (b), pyridine-2,5-dicarboxylic acid (c), benzene-1,2,3,4,5-pentacarboxylic acid (d) and 1,2,3,4,5,6-benzenehexacarboxylic acid (e) have been prepared and characterized by single crystal X-ray diffraction and thermogravimetric analyses. The analysis shows that all the assemblies crystallized as hydrates, except complex, 1c, formed between 1 and pyridine-2,5-dicarboxylic acid. Single crystal X-ray data reveals that the packing patterns of all the molecular complexes have been directed by strong hydrogen bonding O-H⋯O/O-H⋯N/N+-H⋯O- and weak hydrogen bonding C-H⋯O interactions. All the hydrated assemblies aggregate through the formation of cyclic networks as basic recognition pattern. Further, we observed that water molecules play significant role for production of supramolecular assemblies.

  15. Compartmentation of Metabolism of the C12-, C9-, and C5-n-dicarboxylates in Rat Liver, Investigated by Mass Isotopomer Analysis: ANAPLEROSIS FROM DODECANEDIOATE.

    PubMed

    Jin, Zhicheng; Bian, Fang; Tomcik, Kristyen; Kelleher, Joanne K; Zhang, Guo-Fang; Brunengraber, Henri

    2015-07-24

    We investigated the compartmentation of the catabolism of dodecanedioate (DODA), azelate, and glutarate in perfused rat livers, using a combination of metabolomics and mass isotopomer analyses. Livers were perfused with recirculating or nonrecirculating buffer containing one fully (13)C-labeled dicarboxylate. Information on the peroxisomal versus mitochondrial catabolism was gathered from the labeling patterns of acetyl-CoA proxies, i.e. total acetyl-CoA, the acetyl moiety of citrate, C-1 + 2 of β-hydroxybutyrate, malonyl-CoA, and acetylcarnitine. Additional information was obtained from the labeling patterns of citric acid cycle intermediates and related compounds. The data characterize the partial oxidation of DODA and azelate in peroxisomes, with terminal oxidation in mitochondria. We did not find evidence of peroxisomal oxidation of glutarate. Unexpectedly, DODA contributes a substantial fraction to anaplerosis of the citric acid cycle. This opens the possibility to use water-soluble DODA in nutritional or pharmacological anaplerotic therapy when other anaplerotic substrates are impractical or contraindicated, e.g. in propionic acidemia and methylmalonic acidemia.

  16. Penetration of biomass-burning emissions from South Asia through the Himalayas: new insights from atmospheric organic acids.

    PubMed

    Cong, Zhiyuan; Kawamura, Kimitaka; Kang, Shichang; Fu, Pingqing

    2015-01-01

    High levels of carbonaceous aerosol exist over South Asia, the area adjacent to the Himalayas and Tibetan Plateau. Little is known about if they can be transported across the Himalayas, and as far inland as the Tibetan Plateau. As important constituents of aerosols, organic acids have been recognized as unique fingerprints to identify the atmospheric process. Here we measured dicarboxylic acids and related compounds in aerosols on the northern slope of Mt. Everest (Qomolangma, 4276 m a.s.l.). Strong positive correlations were observed for dicarboxylic acids with biomass burning tracers, levoglucosan and K(+), demonstrating that this area was evidently affected by biomass burning. The seasonal variation pattern of dicarboxylic acids is consistent with OC and EC, being characterized by a pronounced maximum in the pre-monsoon season. Molecular distributions of dicarboxylic acids and related compounds (malonic acid/succinic acid, maleic acid/fumaric acid) further support this finding. We suggest that the local meteorological conditions and regional atmospheric flow process could facilitate the penetration of the carbonaceous aerosols from South Asia throughout the Himalayas. With the consideration of the darkening force of carbonaceous aerosols, our finding has important implication for this climate-sensitive area, where the glacier melting supplies water for billions of people downstream. PMID:25854556

  17. Penetration of biomass-burning emissions from South Asia through the Himalayas: new insights from atmospheric organic acids.

    PubMed

    Cong, Zhiyuan; Kawamura, Kimitaka; Kang, Shichang; Fu, Pingqing

    2015-04-09

    High levels of carbonaceous aerosol exist over South Asia, the area adjacent to the Himalayas and Tibetan Plateau. Little is known about if they can be transported across the Himalayas, and as far inland as the Tibetan Plateau. As important constituents of aerosols, organic acids have been recognized as unique fingerprints to identify the atmospheric process. Here we measured dicarboxylic acids and related compounds in aerosols on the northern slope of Mt. Everest (Qomolangma, 4276 m a.s.l.). Strong positive correlations were observed for dicarboxylic acids with biomass burning tracers, levoglucosan and K(+), demonstrating that this area was evidently affected by biomass burning. The seasonal variation pattern of dicarboxylic acids is consistent with OC and EC, being characterized by a pronounced maximum in the pre-monsoon season. Molecular distributions of dicarboxylic acids and related compounds (malonic acid/succinic acid, maleic acid/fumaric acid) further support this finding. We suggest that the local meteorological conditions and regional atmospheric flow process could facilitate the penetration of the carbonaceous aerosols from South Asia throughout the Himalayas. With the consideration of the darkening force of carbonaceous aerosols, our finding has important implication for this climate-sensitive area, where the glacier melting supplies water for billions of people downstream.

  18. Penetration of biomass-burning emissions from South Asia through the Himalayas: new insights from atmospheric organic acids

    NASA Astrophysics Data System (ADS)

    Cong, Zhiyuan; Kawamura, Kimitaka; Kang, Shichang; Fu, Pingqing

    2015-04-01

    High levels of carbonaceous aerosol exist over South Asia, the area adjacent to the Himalayas and Tibetan Plateau. Little is known about if they can be transported across the Himalayas, and as far inland as the Tibetan Plateau. As important constituents of aerosols, organic acids have been recognized as unique fingerprints to identify the atmospheric process. Here we measured dicarboxylic acids and related compounds in aerosols on the northern slope of Mt. Everest (Qomolangma, 4276 m a.s.l.). Strong positive correlations were observed for dicarboxylic acids with biomass burning tracers, levoglucosan and K+, demonstrating that this area was evidently affected by biomass burning. The seasonal variation pattern of dicarboxylic acids is consistent with OC and EC, being characterized by a pronounced maximum in the pre-monsoon season. Molecular distributions of dicarboxylic acids and related compounds (malonic acid/succinic acid, maleic acid/fumaric acid) further support this finding. We suggest that the local meteorological conditions and regional atmospheric flow process could facilitate the penetration of the carbonaceous aerosols from South Asia throughout the Himalayas. With the consideration of the darkening force of carbonaceous aerosols, our finding has important implication for this climate-sensitive area, where the glacier melting supplies water for billions of people downstream.

  19. Carbonization and oxidation of metal-organic frameworks based on 1,4-naphthalene dicarboxylates

    NASA Astrophysics Data System (ADS)

    Chen, Jiun-Jen; Chen, Ya-Ting; Senthil Raja, Duraisamy; Kang, Yu-Hao; Tseng, Pen-Chang; Lin, Chia-Her

    2015-10-01

    Three new isostructural metal-organic frameworks (MOFs), [V(OH)(NDC)] (1), [Cr(OH)(NDC)] (2), and [Ga(OH)(NDC)] (3) have been synthesized hydrothermally using 1,4-naphthalene dicarboxylate (NDC) as the linker. These MOFs (1, 2 and 3) have been used as a template for the synthesis of metal-oxide-inserted nanoporous carbon materials. The newly synthesized MOFs and the resulting porous carbon hybrid functional materials have been characterized using powder x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy dispersive x-ray spectroscopic analysis. Results show that compounds 2 and 3 form their respective metal oxide nanoparticles on the surface of the carbon materials during carbonization at 800 °C. The gas sorption properties of the new MOFs and their corresponding carbon frameworks have been reported.

  20. 2D→3D polycatenated and 3D→3D interpenetrated metal–organic frameworks constructed from thiophene-2,5-dicarboxylate and rigid bis(imidazole) ligands

    SciTech Connect

    Erer, Hakan; Yeşilel, Okan Zafer; Arıcı, Mürsel; Keskin, Seda; Büyükgüngör, Orhan

    2014-02-15

    Hydrothermal reactions of rigid 1,4-bis(imidazol-1-yl)benzene (dib) and 1,4-bis(imidazol-1-yl)-2,5-dimethylbenzene (dimb) with deprotonated thiophene-2,5-dicarboxylic acid (H{sub 2}tdc) in the presence of Zn(II) and Cd(II) salts in H{sub 2}O produced three new metal–organic frameworks, namely, [Zn(µ-tdc)(H{sub 2}O)(µ-dib)]{sub n} (1), [Cd(µ-tdc)(H{sub 2}O)(µ-dib)]{sub n} (2), and ([Cd{sub 2}(µ{sub 3}-tdc){sub 2}(µ-dimb){sub 2}]·(H{sub 2}O)){sub n}(3). These MOFs were characterized by FT-IR spectroscopy, elemental, thermal (TG, DTA, DTG and DSC), and single-crystal X-ray diffraction analyses. Isomorphous complexes 1 and 2 reveal polycatenated 2D+2D→3D framework based on an undulated (4,4)-sql layer. Complex 3 exhibits a new 4-fold interpenetrating 3D framework with the point symbol of 6{sup 6}. Molecular simulations were used to assess the potentials of the complexes for H{sub 2} storage application. Moreover, these coordination polymers exhibit blue fluorescent emission bands in the solid state at room temperature. - Graphical abstract: In this study, hydrothermal reactions of rigid 1,4-bis(imidazol-1-yl)benzene (dib) and 1,4-bis(imidazol-1-yl)-2,5-dimethylbenzene (dimb) with deprotonated thiophene-2,5-dicarboxylic acid (H{sub 2}tdc) in the presence of Zn(II) and Cd(II) salts in H{sub 2}O produced three new metal–organic frameworks. Isomorphous complexes 1 and 2 reveal polycatenated 2D+2D→3D framework based on an undulated (4,4)-sql layer. Complex 3 exhibits a new 4-fold interpenetrating 3D framework with the point symbol of 6{sup 6}. Molecular simulations were used to assess the potentials of the complexes for H{sub 2} storage application. These coordination polymers exhibit blue fluorescent emission bands in the solid state at room temperature. Display Omitted - Highlights: • Complexes 1 and 2 display polycatenated 2D+2D→3D framework. • Complex 3 exhibits a new 4-fold interpenetrating 3D framework. • Complex 1 adsorbs the highest amount of

  1. Di- versus Trinuclear Copper(II) Cryptate for the Uptake of Dicarboxylate Anions.

    PubMed

    Esteves, Catarina V; Mateus, Pedro; André, Vânia; Bandeira, Nuno A G; Calhorda, Maria José; Ferreira, Liliana P; Delgado, Rita

    2016-07-18

    Searching for receptors selective for the binding of dicarboxylate anions, the copper(II) complexes of the known ditopic octaazacryptand (t2pN8), derived from bistren [tren = tris(2-aminoethyl)amine] linked by p-xylyl spacers, were re-examined, with the expectation of observing a selective binding of oxalate or malonate by bridging the two copper centers of the [Cu2(t2pN8)(H2O)2](4+) receptor. Solution studies involving the supramolecular species formed by the receptor and oxalate (oxa(2-)), malonate (mal(2-)), and succinate (suc(2-)) anions are reported. The determined association constants revealed the unexpected formation of a 3:1:1 Cu/t2pN8/anion stoichiometry for the cascade species with oxa(2-) and mal(2-), and the single crystal X-ray structural characterization confirmed the presence of tricopper(II) complexes, with an unusual binding mode for the dicarboxylate anions. Each of the two copper atoms binds four nitrogen donor atoms of the t2pN8 cryptand and one additional hydroxide group, which bridges to the third copper. The square planar environment of this one is complete with two oxygen atoms from the oxalate (or the malonate). The two copper centers bound to the tren heads are ∼6.5 Å apart, each one at about 3.5 Å from the third Cu center. These studies were complemented by SQUID magnetization measurements and DFT calculations. The magnetic susceptibility measurements of the oxalate cascade complex showed a strong magnetic coupling (J = - 210 cm(-1)) between the Cu centers at a short distance (3.5 Å), while the coupling between the two equivalent Cu atoms (∼6.5 Å) was only -70 cm(-1). This result was well reproduced by DFT calculations. PMID:27355987

  2. [Compositions of organic acids in PM10 emission sources in Xiamen urban atmosphere].

    PubMed

    Yang, Bing-Yu; Huang, Xing-Xing; Zheng, An; Liu, Bi-Lian; Wu, Shui-Ping

    2013-01-01

    The possible organic acid emission sources in PM10 in Xiamen urban atmosphere such as cooking, biomass burning, vehicle exhaust and soil/dust were obtained using a re-suspension test chamber. A total of 15 organic acids including dicarboxylic acids, fatty acids and aromatic acids were determined using GC/MS after derivatization with BF3/n-butanol. The results showed that the highest total concentration of 15 organic acids (53%) was found in cooking emission and the average concentration of the sum of linoleic acid and oleic acid was 24% +/- 14%. However, oxalic acid was the most abundant species followed by phthalic acid in gasoline vehicle exhaust. The ratios of adipic to azelaic acid in gasoline combustion emissions were significantly higher than those in other emission sources, which can be used to qualitatively differentiate anthropogenic and biological source of dicarboxylic acids in atmospheric samples. The ratios of malonic to succinic acid in source emissions (except gasoline generator emissions) were lower (0.07-0.44) than ambient PM10 samples (0.61-3.93), which can be used to qualitatively differentiate the primary source and the secondary source of dicarboxylic acids in urban PM10.

  3. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part I. Regeneration of Amine-Carboxylic Acid Extracts

    SciTech Connect

    Poole, L.J.; King, C.J.

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO{sub 2} and H{sub 2}S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, succinic acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The concentration

  4. Acid precipitation - (Part I). Hearings before the Subcommittee on Health and the Environment of the Committee on Energy and Commerce, House of Representatives, Ninety-Seventh Congress, First Session on Effects and Solutions to Combat Acid Precipitation

    SciTech Connect

    Not Available

    1982-01-01

    Part 1 of the record covers three days of hearings on effects of acid rain and possible solutions to combat it. The 24 witnesses include a panel of business representatives from the Adirondacks area of New York, spokesmen from four other states affected by acid rain, and representatives of the Northeast States, all of whom described the threat to animal life in the lakes and streams, to lumber, and to human life because of acidification.

  5. Structural modulation and luminescent properties of four CdII coordination architectures based on 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole and flexible/rigid dicarboxylate ligands

    NASA Astrophysics Data System (ADS)

    Xia, Liang; Dong, Wen-Wen; Ye, Xiao; Zhao, Jun; Li, Dong-Sheng

    2016-10-01

    To systematically investigate the influence of the flexible or rigid auxiliary ligands on the structures and properties of transition metal compounds, we synthesized four new d10 coordination polymers (CPs) from 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (4-Hpzpt) and flexible/rigid dicarboxylate ligands, [Cd(4-pzpt)2]n (1), [Cd3(4-pzpt)2(suc)2]n (2), [Cd2(4-Hpzpt)(nbc)2(H2O)]n (3) and {[Cd2(4-pzpt)2(tfbdc)(H2O)4]·H2O}n (4) (H2suc=1,2-ethanedicarboxylic acid, H2nbc=hthalene-1,4-dicarboxylic acid, H2tfbdc =2,3,5,6-tetrafluoroterephthalic acid). Single crystal X-ray analysis indicates that compound 1 shows a 44-sql layer, which is extended to a 3D network via nonclassical C-H…N hydrogen bonds. Compound 2 possesses a 6-connected pcu-4120.63 net composed of trinuclear CdII-clusters. Compound 3 represents a rare 3D (3,4,4,5)-connected topology with a Schläfli symbol of (4·6·7)(4·53·72)(53·6·7·9)(42·55·6·72). Compound 4 exhibits a 2D+2D→2D parallel interpenetrated 63-hcb network. The adjacent 2D networks are interdigitated with each other to form the resulting 3D supramolecular architecture through classical O-H…N and O-H…O hydrogen bonds. Structural diversities indicate that the nature of flexible/rigid-dicarboxlates plays crucial roles in modulating structures of these compounds. Moreover, the luminescent properties of them have been briefly investigated.

  6. Poly[[tetra­aqua­bis­(μ3-pyridine-2,6-dicarboxyl­ato)(μ2-pyridine-2,6-dicarboxyl­ato)dilanthanum(III)] dihydrate

    PubMed Central

    Lush, Shie Fu; Shen, Fwu Ming

    2011-01-01

    There are two independent LaIII cations in the polymeric title compound, {[La2(C7H3NO4)3(H2O)4]·2H2O}n. One is nine-coordinated in an LaN2O7 tricapped trigonal–prismatic geometry formed by three pyridine-2,6-dicarboxyl­ate anions and two water mol­ecules, while the other is ten-coordinated in an LaNO9 bicapped square-anti­prismatic geometry formed by four pyridine-2,6-dicarboxyl­ate anions and two water mol­ecules. The two LaIII cations are separated by a non-bonding distance of 5.026 (3) Å. The pyridine-2,6-dicarboxyl­ate anions bridge the LaIII cations, forming a three-dimensional polymeric complex. The crystal structure contains extensive classical O—H⋯O hydrogen bonds and weak inter­molecular C—H⋯O hydrogen bonds. The crystal structure is further consolidated by π–π stacking between pyridine rings, the shortest centroid–centroid distance between parallel pyridine rings being 3.700 (5) Å. PMID:22064837

  7. Uptake of 4-chloro-2-methylphenoxyacetic acid (MCPA) from the apical membrane of Caco-2 cells by the monocarboxylic acid transporter

    SciTech Connect

    Kimura, Osamu; Tsukagoshi, Kensuke; Endo, Tetsuya

    2008-03-15

    The cellular uptake mechanism of 4-chloro-2-methylphenoxyacetic acid (MCPA), a phenoxyacetic acid derivative, was investigated using Caco-2 epithelial cells. The cells were incubated with 50 {mu}M MCPA at pH 6.0 and 37 deg. C, and the uptake of MCPA from the apical membranes was measured. The uptake of MCPA was significantly decreased by incubation at low temperature (4 {sup o}C) and markedly increased by lowering the extracellular pH. Pretreatment with a protonophore, carbonylcyanide-p-(trifluoromethoxy)phenylhydrazone (25 {mu}M), or metabolic inhibitors, 2,4-dinitrophenol (1 mM) and sodium azide (10 mM), significantly decreased the uptake of MCPA by 53%, 45% and 48%, respectively. Coincubation of MCPA with 10 mM L-lactic acid or {alpha}-cyano-4-hydroxycinnamate, which is a substrate or an inhibitor of the monocarboxylic acid transporters (MCTs), significantly decreased the uptake of MCPA by 31% and 20%, respectively, and coincubation with benzoic acid profoundly decreased the uptake by 68%. In contrast, coincubation with succinic acid (a dicarboxylic acid) did not affect the uptake. Kinetic analysis of initial MCPA uptake suggested that MCPA is taken up via a carrier-mediated process [K{sub m} = 1.37 {+-} 0.15 mM, V{sub max} = 115 {+-} 6 nmol (mg protein){sup -1} (3 min){sup -1}]. Lineweaver-Burk plots show that benzoic acid competitively inhibits the uptake of MCPA with a K{sub i} value of 4.68 {+-} 1.76 mM. A trans-stimulation effect on MCPA uptake was found in cells preloaded with benzoic acid. These results suggest that the uptake of MCPA from the apical membrane of Caco-2 cells is mainly mediated by common MCTs along with benzoic acid but also in part by L-lactic acid.

  8. Assembly and property research on seven 0D–3D complexes derived from imidazole dicarboxylate and 1,2-bi(pyridin-4-yl)ethene

    SciTech Connect

    Mu, Bao; Li, Qian; Lv, Lei; Yang, Dan-Dan; Wang, Qing; Huang, Ru-Dan

    2015-03-15

    The hydrothermal reaction of transition metals, 1H-imidazole-4,5-dicarboxylic acid (H{sub 3}ImDC) and 1,2-bi(pyridin-4-yl)ethene (bpe) affords a series of new complexes, namely, [Mn(HImDC)(bpe)(H{sub 2}O)] (1), [M(H{sub 2}ImDC){sub 2}(H{sub 2}O){sub 2}]·(bpe) (M=Fe(2), Co(3), Zn(4), Cd(6)), [Zn{sub 3}(ImDC){sub 2}(bpe)(H{sub 2}O)]·3H{sub 2}O (5) and [Cd(H{sub 2}ImDC)(bpe)] (7), which are characterized by elemental analyses, IR, TG, XRPD and single crystal X-ray diffraction. Complex 1 exhibits a one dimensional (1D) zigzag chain with two types of irregular rings, and the 1D chains are linked to form a three dimensional (3D) supramolecular framework by the hydrogen bonding interactions (O–H∙∙∙O and O–H∙∙∙N). Complexes 2–4 and 6 are isomorphous, and they display the mononuclear structures. In these complexes, the O–H∙∙∙O and O–H∙∙∙N hydrogen bonds play an important role in sustaining the whole 3D supramolecular frameworks. Complex 5 shows a (3,3)-connected 3D framework with (10{sup 3}) topology, and the lattice water molecules as guest molecules exist in the 3D framework. Complex 7 is a wave-like two dimensional (2D) structure, in which the adjacent 1D chains point at the opposite directions. Moreover, the fluorescent properties of complexes 1–7 and the magnetic property of 1 have been investigated. The water vapor adsorption for complex 5 has been researched at 298 K. - Graphical abstract: Seven new complexes based on different structural characteristics have been hydrothermally synthesized by the mixed ligands. The fluorescent properties, the magnetic property and the water vapor adsorption have been investigated. - Highlights: • The semi-rigid ligand with C=C bonds and imidazole dicarboxylates with some advantages have been used. • A series of new complexes with different structural characteristics have been discussed in detail. • The fluorescent properties, the magnetic property and the water vapor adsorption have been

  9. 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

  10. Synthesis, crystal structures, and properties of two novel cadmium(II)-organic frameworks based on asymmetric dicarboxylate and N-donor ligands

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoli; Gao, Loujun; Zhang, Xiaoge; Han, Xuhua; Wang, Yao; Sun, Rong

    2014-08-01

    Two novel cadmium(II)-organic frameworks with asymmetric dicarboxylate and N-donor ligands, namely [Cd(cpa)(phen)]n (1) and {[Cd2(cpa)2(bpy)1.5]·0.5H2O}n (2) (H2cpa = 3-(4-benzoic)propionic acid, phen = 1,10-phenanthroline, bpy = 4,4";-bipyridine) have been hydrothermally synthesized and characterized by elemental analyses, FT-IR spectra, single-crystal X-ray diffraction analyses, TGA, powder XRD and fluorescent measurements. 1 displays a double zigzag chain structure containing 8-number and 22-number circles. 2 Shows a 6-connected 3D polymer network based on tetranuclear cadmium cluster units. The most striking feature of 2 is that a pair of identical 3D networks are interlocked with each other to the form a 2-fold interpenetrated 3D α-Po structural topology. The diverse structures of two complexes indicate that the skeleton of N-donor ligands plays a great role in the assembly of such different frameworks. In addition, the thermal stabilities, XRD and photoluminescence properties of 1-2 were also studied.

  11. Lanthanide-Potassium Biphenyl-3,3'-disulfonyl-4,4'-dicarboxylate Frameworks: Gas Sorption, Proton Conductivity, and Luminescent Sensing of Metal Ions.

    PubMed

    Zhou, Li-Juan; Deng, Wei-Hua; Wang, Yu-Ling; Xu, Gang; Yin, Shun-Gao; Liu, Qing-Yan

    2016-06-20

    A novel sulfonate-carboxylate ligand of biphenyl-3,3'-disulfonyl-4,4'-dicarboxylic acid (H4-BPDSDC) and its lanthanide-organic frameworks {[LnK(BPDSDC)(DMF)(H2O)]·x(solvent)}n (JXNU-2, where JXNU denotes Jiangxi Normal University, DMF indicates dimethylformamide, and Ln = Sm(3+), Eu(3+), and Pr(3+)) were synthesized and structurally characterized. The three isomorphous lanthanide compounds feature three-dimensional frameworks constructed from one-dimensional (1D) rod-shaped heterometallic Ln-K secondary building units and are an illustration of a Kagome-like lattice with large 1D hexagonal channels and small 1D trigonal channels. The porous material of the representive JXNU-2(Sm) has an affinity to quadrupolar molecules such as CO2 and C2H2. In addition, the JXNU-2(Sm) compound exhibits humidity- and temperature-dependent proton conductivity with a large value of 1.11 × 10(-3) S cm(-1) at 80 °C and 98% relative humidity. The hydrophilic sulfonate group on the surface of channels facilitates enrichment of the solvate water molecules in the channels, which enhances the proton conductivity of this material. Moreover, the JXNU-2(Eu) material with the characteristic bright red color shows the potential for recognition of K(+) and Fe(3+) ions. The enhancing Eu(3+) luminescence with the K(+) ion and quenching Eu(3+) luminescence with the Fe(3+) ion can be associated with the functional groups of the organic ligand.

  12. Highly sensitive optical sensor that detects Hg2+ and Cu2+ by immobilizing dicarboxylate 1,5-diphenyl-3-thiocarbazone on surface functionalized PVA microspheres

    NASA Astrophysics Data System (ADS)

    Bai, Xue; Gu, Haixin; Hua, Zulin; Dai, Zhangyan; Yang, Bei; Li, Yulong

    2015-11-01

    A novel optical sensor to detect Hg2+ and Cu2+ is prepared by immobilizing a synthesized dicarboxylate 1,5-diphenyl-3-thiocarbazone (DDT) group on functionalized polyvinyl alcohol (PVA) microspheres. This optical sensor is successfully fabricated by extensive characterization with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Its colorimetric properties, selectivity, sensitivity, and reversibility are investigated as well. In this sensing system, DDT-PVA selectively recognized multiple heavy metal ions, as indicated by the changes in color from orange to scarlet for Hg2+ and from orange to gray for Cu2+. In particular, this optical sensor exhibits the most apparent color changes at pH levels of 12 and 2. Hence, Hg2+ and Cu2+ can be detected in aqueous solution at minimum detection limits of 0.053 and 0.132 μM, respectively, with a UV-vis spectrometer. Furthermore, the sensor can be regenerated by ethylene diamine tetraacetic acid and reused several times. Therefore, the optical sensor can detect Hg2+ because of its selectivity, sensitivity, and reversibility.

  13. Oxidant and acid aerosol exposure in healthy subjects and subjects with asthma. Part 1. Effects of oxidants, combined with sulfuric or nitric acid, on the pulmonary function of adolescents with asthma. Part 2. Effects of sequential sulfuric acid and ozone exposures on the pulmonary function of healthy subjects and subjects with asthma. Research report, February 1989-April 1994

    SciTech Connect

    Koenig, J.Q.; Covert, D.S.; Pierson, W.E.; Hanley, Q.S.; Rebolledo, V.

    1994-11-01

    The study investigated the pulmonary effects of acid summer haze in a controlled laboratory setting. Of 28 adolescent subjects with allergic asthma, exercise-induced bronchospasm, and a positive response to a standardized methacholine challenge enrolled in the study, 22 completed the study. For two consecutive days each subject inhaled each of four test atmospheres by mouthpiece. The order of exposure to the four test atmospheres was assigned via a random protocol; air, oxidants (0.12 parts per million (ppm) ozone plus 0.30 ppm nitrogen dioxide), oxidants plus sulfuric acid at 70 micro/m3 of air, or oxidants plus 0.05 ppm nitric acid. Exposure to each of the different atmospheres was separated by at least one week. A postexposure methacholine challenge was performed on Day 3.

  14. Inhibition of N-acetylglutamate synthase by various monocarboxylic and dicarboxylic short-chain coenzyme A esters and the production of alternative glutamate esters.

    PubMed

    Dercksen, M; IJlst, L; Duran, M; Mienie, L J; van Cruchten, A; van der Westhuizen, F H; Wanders, R J A

    2014-12-01

    Hyperammonemia is a frequent finding in various organic acidemias. One possible mechanism involves the inhibition of the enzyme N-acetylglutamate synthase (NAGS), by short-chain acyl-CoAs which accumulate due to defective catabolism of amino acids and/or fatty acids in the cell. The aim of this study was to investigate the effect of various acyl-CoAs on the activity of NAGS in conjunction with the formation of glutamate esters. NAGS activity was measured in vitro using a sensitive enzyme assay with ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) product analysis. Propionyl-CoA and butyryl-CoA proved to be the most powerful inhibitors of N-acetylglutamate (NAG) formation. Branched-chain amino acid related CoAs (isovaleryl-CoA, 3-methylcrotonyl-CoA, isobutyryl-CoA) showed less pronounced inhibition of NAGS whereas the dicarboxylic short-chain acyl-CoAs (methylmalonyl-CoA, succinyl-CoA, glutaryl-CoA) had the least inhibitory effect. Subsequent work showed that the most powerful inhibitors also proved to be the best substrates in the formation of N-acylglutamates. Furthermore, we identified N-isovalerylglutamate, N-3-methylcrotonylglutamate and N-isobutyrylglutamate (the latter two in trace amounts), in the urines of patients with different organic acidemias. Collectively, these findings explain one of the contributing factors to secondary hyperammonemia, which lead to the reduced in vivo flux through the urea cycle in organic acidemias and result in the inadequate elimination of ammonia.

  15. Possible carcinogenic potential of dimethyl dimethoxy biphenyl dicarboxylate in experimental animals

    PubMed Central

    Botros, Sanaa Sabet; El-Lakkany, Naglaa Mohamed; Hammam, Olfat Ali; Sabra, Abdel-Naser Abdel-Aal; Taha, Alaa Awad

    2016-01-01

    Dimethyl dimethoxy biphenyl dicarboxylate (DDB) has been extensively used in the treatment of liver diseases accounting for 1–6% of the global disease burden. Cell replication, DNA synthesis, and proliferation, providing significant information about behavior of cells were examined in mice exposed to subchronic administration with DDB. Conventional liver functions specifically gamma-glutamyltransferase (γ-GT), a marker expressing liver canceration was also investigated. Normal mice were allocated into two groups each of 10 mice. The 1st and 2nd groups were treated with DDB in a dose of 50 mg/kg/day, 5 days/week for 1 month and 3 months, respectively. Comparable groups of normal mice were left without treatment as controls. Compared to normal control group, animals receiving DDB for 3 months showed marked elevations of both alanine aminotransferase and γ-GT, significant inhibition in cytochrome P450, a significant increase in the mean ploidy and 4C with moderate to marked increase in S-phase populations and the number of proliferating cell nuclear antigen-positive cells. In conclusion, this is the first report on the potential relationship between the subchronic administration of DDB and the increase in the hepatocyte proliferation, cell replication and DNA synthesis that may raise an alarm regarding possible DDB insult on the biological behavior of cells. PMID:27144153

  16. [Amino acid composition and quaternary structure of glucosoisomerase (d-xylose-ketol-isomerase) from Actinomyces olivocinereus 154].

    PubMed

    Rezchikov, A A; Ulezlo, I V; Ananichev, A V; Bezborodov, A M

    1980-01-01

    The amino acid composition of glucosoisomerase from Actinomyces olivocinereus 154 was investigated. The content of dicarboxylic acids--aspartic and glutamic--was found to be greater than that of basic acids--lysine, arginine and histidine. Hydrophobic acids were also detected to occur on appreciable quantities. No cysteine was seen in the enzyme. The experimental data on the effect of sodium dodecyl sulfate and urea suggests that the enzyme has a quaternary structure consisting of four nonidentical subunits. PMID:7220510

  17. Polymerized fatty acid amine derivatives useful as friction and wear-reducing additives

    SciTech Connect

    Coupland, K.; Smith, C.R.

    1981-02-10

    A hydrocarbon composition having a major portion of a hydrocarbon preferably a lubricating oil such as mineral oil and at least a friction-reducing amount usually 0.01 to 10 weight percent of an amine or amine derivative of a hydrocarbon-soluble polymerized fatty acid e.g. a dimeramine derived from a dicarboxylic acid containing at least 12 carbon atoms such as 9(10)-carboxy stearic acid has improved antifriction and flue economy properties.

  18. Polymerization of beta-amino acids in aqueous solution

    NASA Technical Reports Server (NTRS)

    Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged alpha- and beta-amino acids in homogeneous aqueous solution. alpha-Amino acids can be oligomerized efficiently using CDI, but not by EDAC. beta-Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an alpha- and beta-dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.

  19. Purification process for succinic acid produced by fermentation

    SciTech Connect

    Glassner, D.A.; Elankovan, P.; Beacom, D.R.

    1995-12-31

    Succinic acid is a versatile four-carbon dicarboxylic acid. It can be used commercially as an intermediate chemical for the manufacture of 1,4-butanediol, maleic anhydride, and many other chemicals. Succinic acid can be produced by the fermentation of carbohydrates. A complete process for the production and purification of succinic acid from carbohydrates has been developed. The process includes fermentation, desalting electrodialysis, water-splitting electrodialysis, and crystallization to produce a pure crystalline succinic acid. This article will present experimental work performed in the development of this process.

  20. Amino acids as co-amorphous stabilizers for poorly water-soluble drugs--Part 2: molecular interactions.

    PubMed

    Löbmann, Korbinian; Laitinen, Riikka; Strachan, Clare; Rades, Thomas; Grohganz, Holger

    2013-11-01

    The formation of co-amorphous drug-drug mixtures has proved to be a powerful approach to stabilize the amorphous form and at the same time increase the dissolution of poorly water-soluble drugs. Molecular interactions in these co-amorphous formulations can play a crucial role in stabilization and dissolution enhancement. In this regard, Fourier-transform infrared spectroscopy (FTIR) is a valuable tool to analyze the molecular near range order of the compounds in the co-amorphous mixtures. In this study, several co-amorphous drugs--low molecular weight excipient blends--have been analyzed with FTIR spectroscopy. Molecular interactions of the drugs carbamazepine and indomethacin with the amino acids arginine, phenylalanine, and tryptophan were investigated. The amino acids were chosen from the biological target site of both drugs and prepared as co-amorphous formulations together with the drugs by vibrational ball milling. A detailed analysis of the FTIR spectra of these formulations revealed specific peak shifts in the vibrational modes of functional groups of drug and amino acid, as long as one amino acid from the biological target site was present in the blends. These peak shifts indicate that the drugs formed specific molecular interactions (hydrogen bonding and π-π interactions) with the amino acids. In the drug-amino acid mixtures that contained amino acids which were not present at the biological target site, no such interactions were identified. This study shows the potential of amino acids as small molecular weight excipients in co-amorphous formulations to stabilize the amorphous form of a poorly water-soluble drug through strong and specific molecular interactions with the drug.

  1. Fluorescent sensing and electrocatalytic properties of three Zn(II)/Co(II) coordination complexes containing two different dicarboxylates and two various bis(pyridyl)-bis(amide) ligands

    NASA Astrophysics Data System (ADS)

    Lin, Hongyan; Rong, Xing; Liu, Guocheng; Wang, Xiang; Wang, Xiuli; Duan, Surui

    2016-09-01

    Three new transition metal(II) coordination complexes constructed from two different dicarboxylates (1,3-H2BDC = 1,3-benzenedicarboxylic acid, 1,4-H2NDC = 1,4-naphthalenedicarboxylic acid) and two bis(pyridyl)-bis(amide) ligands (3-bpcd = N,N‧-bis(3-pyridyl)cyclohexane-1,4-dicarboxamide, 3-bpod = N,N‧-bis(3-pyridyl)octandiamide), [Zn(1,3-BDC)(3-bpcd)0.5(H2O)]·H2O (1), [Zn(1,3-BDC)(3-bpod)0.5(H2O)] (2) and [Co(1,4-NDC)(3-bpod)1.5(H2O)] (3) have been synthesized in the hydrothermal environments and structurally characterized by IR, TG and single crystal X-ray diffraction. Complexes 1 and 2 possess the similar 1D ladder-like chain based on [Zn(1,3-BDC)]n zigzag chain and the bidentate ligands 3-bpcd/or 3-bpod. Complex 3 shows a 2D layered structure with a 5-connected {410} topology, which consists of 1D linear [Co(1,4-NDC)]n chain and [Co(3-bpod)1.5]n chain with alternating arrangement of 3-bpod ligands and Co2(3-bpod)2 dinuclear loops. The adjacent 1D chains for 1-2 or the 2D layers for 3 are further extended into 2D or 3D supramolecular frameworks through the hydrogen bonding interactions. Additionally, the solid state fluorescent properties for the title complexes 1-3, the fluorescent sensing behaviors of complexes 1-2 and the electrochemical behaviour of complex 3 have been investigated.

  2. Fatty acids in sparry calcite fracture fills and microsparite cement of septarian diagenetic concretions

    NASA Astrophysics Data System (ADS)

    Pearson, M. J.; Hendry, J. P.; Taylor, C. W.; Russell, M. A.

    2005-04-01

    Sparry calcite fracture fills and concretion body cements in concretions from the Flodigarry Shale Member of the Staffin Shale Formation, Isle of Skye, Scotland, entrap and preserve mineral and organic materials of sedimentary and diagenetic origin. Fatty acids are a major component of the lipids recovered by decarbonation and comprise mainly n-alkanoic and α-ω dicarboxylic acids. Two generations of fracture-fill calcite (early brown and later yellow) and the concretion body microspar yield significantly different fatty acid profiles. Early brown calcites yield mainly medium-chain n-alkanoic acids with strong even predominance; later yellow calcites are dominated by α-ω dicarboxylic acids with no even predominance. Both fracture fills lack the long-chain n-alkanoic and α-ω dicarboxylic acids additionally recovered from the concretion bodies. The absence of longer chain acids in the calcite spar fracture fills is inferred to result from the transport of fatty acids by septarian mineralising fluids whereby low-aqueous solubility of longer chain acids or their salts accounts for their relative immobility. Comparative experiments have been carried out using conventional solvent extraction on the concretion body and associated shales, both decarbonated and untreated. Extracted lipid yields are higher, but the fatty acids probably derive from mixed locations in the rock including both kerogen- and carbonate-associated lipid pools. Only experiments involving decarbonation yielded α-ω dicarboxylic acids in molecular distributions probably controlled mainly by fluid transport. Alkane biomarker ratios indicate very low thermal maturity has been experienced by the concretions and their host sediments. Septarian cracks lined by brown calcite formed during early burial. Microbial CO 2 from sulphate-reducing bacteria was probably the main source of mineralising carbonate. Emplacement of the later septarian fills probably involved at least one episode of fluid invasion.

  3. Alteration of organic matter during infaunal polychaete gut passage and links to sediment organic geochemistry. Part I: Amino acids

    NASA Astrophysics Data System (ADS)

    Woulds, Clare; Middelburg, Jack J.; Cowie, Greg L.

    2012-01-01

    Of the factors which control the quantity and composition of organic matter (OM) buried in marine sediments, the links between infaunal ingestion and gut passage and sediment geochemistry have received relatively little attention. This study aimed to use feeding experiments and novel isotope tracing techniques to quantify amino acid net accumulation and loss during polychaete gut passage, and to link this to patterns of selective preservation and decay in sediments. Microcosms containing either Arenicolamarina or Hediste (formerly Nereis) diversicolor were constructed from defaunated sediment and filtered estuarine water, and maintained under natural temperature and light conditions. They were fed with 13C-labelled diatoms daily for 8 days, and animals were transferred into fresh, un-labelled sediment after ∼20 days. Samples of fauna, microcosm sediment and faecal matter were collected after 8, ∼20 and ∼40 days, and analysed for their bulk isotopic signatures and 13C-labelled amino acid compositions. Bulk isotopic data showed that, consistent with their feeding modes, Hediste assimilated added 13C more quickly, and attained a higher labelling level than Arenicola. Both species retained the added 13C in their biomass even after removal from the food. A principal component analysis of 13C-labelled amino acid mole percentages showed clear differences in composition between the algae, faunal tissues, and sediment plus faecal matter. Further, the two species of polychaete showed different compositions in their tissues. The amino acids phenylalanine, valine, leucine, iso-leucine, threonine and proline showed net accumulation in polychaete tissues. Serine, methionine, lysine, aspartic and glutamic acids and tyrosine were rapidly lost through metabolism, consistent with their presence in easily digestible cell components (as opposed to cell walls which offer physical protection). All sample types (polychaete tissues, sediments and faecal matter) were enriched in

  4. Dianthosaponins G-I, triterpene saponins, an anthranilic acid amide glucoside and a flavonoid glycoside from the aerial parts of Dianthus japonicus and their cytotoxicity.

    PubMed

    Kanehira, Yuka; Kawakami, Susumu; Sugimoto, Sachiko; Matsunami, Katsuyoshi; Otsuka, Hideaki

    2016-10-01

    Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of the aerial parts of Dianthus japonicus afforded three further triterpene glycosyl estsers, termed dianthosaponins G-I, an anthranilic acid amide glucoside and a C-glycosyl flavonoid along with one known triterpene saponin. Their structures were elucidated from spectroscopic evidence. The cytotoxicity of the isolated compounds toward A549 cells was evaluated.

  5. Dianthosaponins G-I, triterpene saponins, an anthranilic acid amide glucoside and a flavonoid glycoside from the aerial parts of Dianthus japonicus and their cytotoxicity.

    PubMed

    Kanehira, Yuka; Kawakami, Susumu; Sugimoto, Sachiko; Matsunami, Katsuyoshi; Otsuka, Hideaki

    2016-10-01

    Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of the aerial parts of Dianthus japonicus afforded three further triterpene glycosyl estsers, termed dianthosaponins G-I, an anthranilic acid amide glucoside and a C-glycosyl flavonoid along with one known triterpene saponin. Their structures were elucidated from spectroscopic evidence. The cytotoxicity of the isolated compounds toward A549 cells was evaluated. PMID:27351981

  6. Phenolic acid derivatives with potential anticancer properties--a structure-activity relationship study. Part 1: methyl, propyl and octyl esters of caffeic and gallic acids.

    PubMed

    Fiuza, S M; Gomes, C; Teixeira, L J; Girão da Cruz, M T; Cordeiro, M N D S; Milhazes, N; Borges, F; Marques, M P M

    2004-07-01

    The antiproliferative and cytotoxic properties of polyphenolic acid derivatives, structurally related with the natural models caffeic and gallic acids, have been tested in human cervix adenocarcinoma cells (HeLa). Simultaneous structural information was obtained for these compounds through theoretical ab initio methods. This study was conducted for the following esters: methyl caffeate (MC, 1), propyl caffeate (PC, 2), octyl caffeate (OC, 3), methyl gallate (MG, 4), propyl gallate (PG, 5) and octyl gallate (OG, 6). A significant growth-inhibition effect was assessed for some of these compounds, clearly dependent on their structural characteristics. Marked structure-activity relationships (SARs)--namely the number of hydroxyl ring substituents--were found to rule the biological effect of such systems.

  7. Extraction of benzene and naphthalene carboxylic acids using quaternary ammonium salts as a model study for the separation of coal oxidation products

    SciTech Connect

    Kawamura, K.; Nagano, H.; Okuwaki, A.

    2005-07-01

    The ion-pair solvent extraction of benzene- and naphthalene-carboxylic acids has been investigated as a model study for the separation of coal oxidation products, which are formed by treatment with alkaline solutions at high temperatures. It was possible that benzene- and naphthalene-dicarboxylic acids are extracted into several types of organic solvents with quaternary ammonium ions. The extraction equilibrium constants (K{sub ex}) for benzoic acid, 1,2-benzenedicarboxylic acid, 1,3-benzenedicarboxylic acid, 1-naphthoic acid, 2-naphthoic acid, 2,3-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid into chloroform were determined at 20{sup o}C. The difference of K{sub ex} among the aromatic acids was sufficiently large for designing a separation method for these aromatic acids. It was unexpected that the extraction of dicarboxylic acids was slower than that of monocarboxylic acids, although the ion-pair formation of aromatic carboxylate ion with quaternary ammonium ion is normally considered as a diffusion control reaction in aqueous phase. Thus, this fact suggests that the phase transfer of the ion-pair from aqueous to organic phase is the rate-determining step. Liner-free-energy relationship was observed for the monocarboxylic acids using different quaternary ammonium salts while that was ambiguous for the dicarboxylic acids. This is due to the steric influence of the counter ions for the magnitude of K{sub ex}.

  8. Studies of the pulse charge of lead-acid batteries for PV applications. Part III. Electrolyte concentration effects on the electrochemical performance of the positive plate

    NASA Astrophysics Data System (ADS)

    Kirchev, A.; Delaille, A.; Karoui, F.; Perrin, M.; Lemaire, E.; Mattera, F.

    2008-05-01

    In the third part of this work the effects of the sulphuric acid concentration on the positive plate discharge capacity, impedance and oxygen overvoltage are discussed. It has been found that the full discharge capacity of the positive plate is available down to electrolyte concentrations of 3 mol l-1 (s.g. 1.18 g ml-1). At further acid dilution, capacity of the positive plate declines, keeping the utilization of the sulphuric acid about 50%. Decreasing the acid concentration, the oxygen overvoltage decreases with a factor of 12-18 mV M-1, excluding the effect of the equilibrium potential of the oxygen electrode as a function of pH. The capacitance of the electrical double layer decrease linearly with the dilution of the sulphuric acid suggesting strong adsorption effects. This suggestion has been confirmed from the measurements of potential of the zero charge of the positive plate, which increases from 1.11 to 1.34 V vs. Ag/Ag2SO4 in the region 1.11-4.60 M H2SO4. From the measurement of the time constant of the electronic transfer through the gel part of the lead dioxide (Tgel) as a function of the acid concentration and the applied potential, a change in the mechanism of the lead dioxide hydration has been estimated-below 1 M H2SO4Tgel increases sharply, showing sharp increases of the extent of the hydration. The dilution of the electrolyte increases substantially the value of average double layer current in the beginning of the charge. During the pulse overcharge at the employed frequency of 1 Hz, the average double layer current is equal to the pulse amplitude, suggesting that the maximal efficiency of the pulse charge is reached.

  9. Occurrence and characterization of oils rich in gamma-linolenic acid part II: fatty acids and squalene from Macaronesian Echium leaves.

    PubMed

    Guil-Guerrero, J L; García-Maroto, F; Campra-Madrid, P; Gómez-Mercado, F

    2000-06-01

    Leaves from 25 Macaronesian Echium (Boraginaceae) species have been surveyed for hydrocarbon compounds. These plants were previously reported as the major source of gamma-linolenic acid so far found in nature. In addition, six European Echium species and the common Borago officinalis have been analysed for comparative purposes. High squalene amounts were found in all Echium plants from the Macaronesia, ranging from 3.73%, in E. simplex to 20.1% in E. fastousum. Squalene was almost absent from all European Echium species, and the same is true for B. officinalis. The relatively high oil content (2.27%) in leaves of E. fastuosum raises the total squalene amount to about 0.46% within this tissue. The main fatty acid component in the leaf was alpha-linolenic acid (ALA, 18:3omega3), ranging in the Macaronesian Echium from 9.32% in E. acanthocarpum to 54.45% in E. simplex. Possible utilisation of these plants as a commercial source of squalene and hypotheses about its physiological role in the plant are discussed. PMID:10939357

  10. Development of a New Antileishmanial Aziridine-2,3-Dicarboxylate-Based Inhibitor with High Selectivity for Parasite Cysteine Proteases

    PubMed Central

    Schad, Caroline; Baum, Ulrike; Frank, Benjamin; Dietzel, Uwe; Mattern, Felix; Gomes, Carlos; Ponte-Sucre, Alicia; Moll, Heidrun

    2015-01-01

    Leishmaniasis is one of the major neglected tropical diseases of the world. Druggable targets are the parasite cysteine proteases (CPs) of clan CA, family C1 (CAC1). In previous studies, we identified two peptidomimetic compounds, the aziridine-2,3-dicarboxylate compounds 13b and 13e, in a series of inhibitors of the cathepsin L (CL) subfamily of the papain clan CAC1. Both displayed antileishmanial activity in vitro while not showing cytotoxicity against host cells. In further investigations, the mode of action was characterized in Leishmania major. It was demonstrated that aziridines 13b and 13e mainly inhibited the parasitic cathepsin B (CB)-like CPC enzyme and, additionally, mammalian CL. Although these compounds induced cell death of Leishmania promastigotes and amastigotes in vitro, the induction of a proleishmanial T helper type 2 (Th2) response caused by host CL inhibition was observed in vivo. Therefore, we describe here the synthesis of a new library of more selective peptidomimetic aziridine-2,3-dicarboxylates discriminating between host and parasite CPs. The new compounds are based on 13b and 13e as lead structures. One of the most promising compounds of this series is compound s9, showing selective inhibition of the parasite CPs LmaCatB (a CB-like enzyme of L. major; also named L. major CPC) and LmCPB2.8 (a CL-like enzyme of Leishmania mexicana) while not affecting mammalian CL and CB. It displayed excellent leishmanicidal activities against L. major promastigotes (50% inhibitory concentration [IC50] = 37.4 μM) and amastigotes (IC50 = 2.3 μM). In summary, we demonstrate a new selective aziridine-2,3-dicarboxylate, compound s9, which might be a good candidate for future in vivo studies. PMID:26596939

  11. Water-deficit impact on fatty acid and essential oil composition and antioxidant activities of cumin (Cuminum cyminum L.) aerial parts.

    PubMed

    Bettaieb, Iness; Knioua, Sana; Hamrouni, Ibtissem; Limam, Ferid; Marzouk, Brahim

    2011-01-12

    This study is designed to examine the effect of water deficit on growth, fatty acid and essential oil composition, and antioxidant activities of Cuminum cyminum aerial part extracts. Plants were treated with different levels of water deficit: control (C), moderate water deficit (MWD), and severe water deficit (SWD). Plant growth (height, fresh and dry matter weights) as well as yield components were significantly increased under moderate water deficit and conversely reduced at severe level. Total fatty acid content decreased significantly with severity of constraint. Drought reduced considerably the proportions of major fatty acids and the unsaturated to saturated fatty acid ratio. The essential oil yield was 0.14% (based on the dry weight); it increased by 2.21-fold at MWD but decreased by 42.8% under SWD in comparison to the control. Drought results in the modification of the essential oil chemotype from 1-phenyl-1-butanol to 1-phenyl-1,2-ethanediol. Antioxidant activities of the acetone extracts were determined by two complementary test systems, namely, DPPH and β-carotene/linoleic acid. The highest activity was exhibited by moderately stressed plants and was reduced significantly under SWD. In control plants, the total phenolic amount was 10.23 mg GAE/g DW, which increased by 1.5-fold under MWD and decreased by 42% under SWD.

  12. 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

  13. 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.

  14. 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.

  15. Compliance with revised acid rain monitoring requirements for gas and oil fired units: Appendix D and E of Part 75

    SciTech Connect

    Sheppard, M.; Culligan, K.

    1995-12-31

    EPA`s CEM rule (40 CFR Part 75) implements the monitoring provisions of Title IV of the Clean Air Act Amendments of 1990. In most cases Part 75 requires utilities to monitor sulfur dioxide (SO{sub 2}), nitrogen oxide (NO{sub x}) and carbon dioxide emissions (CO{sub 2}), and volumetric flow and opacity using Continuous Emissions Monitoring Systems (CEMS). Appendix D and E of 40 CFR Part 75 provide alternatives to using Continuous Emissions Monitoring Systems (CEMS) to comply with the monitoring requirements of Title IV of the Clean Air Act. EPA is considering a number of changes to Part 75, including significant changes to Appendix D and E. Part 75 was originally promulgated on January 11, 1993. Due to both experience gained in the implementation of Phase 1 and the early implementation of Phase 2 and petitions filed by several groups, EPA has prepared a number of changes to Part 75. This paper discusses what EPA anticipates these changes will be and how EPA anticipates that these changes will affect the regulated community. In addition, it discusses EPA`s expectations for certification applications for units using Appendix D and E.

  16. Reactions of tetraphenyltitanium with organic acids

    SciTech Connect

    Razuvaev, G.A.; Vyshinskaya, L.I.; Vasil'eva, G.A.

    1987-12-10

    As a result of the reactions of tetraphenyltitanium with dibasic organic acids high yields were obtained of new thermally stable titanium(III) complexes: phenyltitanium(III)carboxylates. Under the action of proton-active reagents (hydrochloric acid, cyclopentadiene, methanol) the latter break down with the breakage of titanium-phenyl bond. The proposed structure was based on IR- and ESR-spectral data. The dinuclear structure of the complexes was established on the basis of a study of the triplet structure of the ESR spectra, which showed the existence of intermolecular titanium-titanium exchange through methylene groups of the dicarboxylate bridges.

  17. Defensive strategies in Geranium sylvaticum. Part 1: organ-specific distribution of water-soluble tannins, flavonoids and phenolic acids.

    PubMed

    Tuominen, Anu; Toivonen, Eija; Mutikainen, Pia; Salminen, Juha-Pekka

    2013-11-01

    A combination of high-resolution mass spectrometry and modern HPLC column technology, assisted by diode array detection, was used for accurate characterization of water-soluble polyphenolic compounds in the pistils, stamens, petals, sepals, stems, leaves, roots and seeds of Geranium sylvaticum. The organs contained a large variety of polyphenols, five types of tannins (ellagitannins, proanthocyanidins, gallotannins, galloyl glucoses and galloyl quinic acids) as well as flavonoids and simple phenolic acids. In all, 59 compounds were identified. Geraniin and other ellagitannins dominated in all the green photosynthetic organs. The other organs seem to produce distinctive polyphenol groups: pistils accumulated gallotannins; petals acetylglucose derivatives of galloylglucoses; stamens kaempferol glycosides, and seeds and roots accumulated proanthocyanidins. The intra-plant distribution of the different polyphenol groups may reflect the different functions and importance of various types of tannins as the defensive chemicals against herbivory.

  18. Characterization of Jamaican agro-industrial wastes. Part II, fatty acid profiling using HPLC: precolumn derivatization with phenacyl bromide.

    PubMed

    Bailey-Shaw, Y A; Golden, K D; Pearson, A G M; Porter, R B R

    2012-09-01

    This paper describes the determination of fatty acid composition of coffee, citrus and rum distillery wastes using reversed-phase high-performance liquid chromatography (RP-HPLC). Lipid extracts of the waste samples are derivatized with phenacyl bromide and their phenacyl esters are separated on a C8 reversed-phase column by using continuous gradient elution with water and acetonitrile. The presence of saturated and unsaturated fatty acids in quantifiable amounts in the examined wastes, as well as the high percentage recoveries, are clear indications that these wastes have potential value as inexpensive sources of lipids. The HPLC procedures described here could be adopted for further analysis of materials of this nature. PMID:22595260

  19. ALS (acidic lithium sulphate) decomposition method (part iv) Kjeldahl determination of nitrogen in heterocyclic ring compounds containing nitrogennitrogen bond.

    PubMed

    Yoshikuni, N

    1994-01-01

    Heterocyclic ring compounds containing nitrogennitrogen bonds such as 1H-1,2,4 triazole, 2,4,6 trimethylbenzenesulfonyltriazolide and pyridazine can be completely decomposed in the molten state with mixtures of various ratios of concentrated sulphuric acid and lithium sulphate (molten ALS) flux containing a catalyst such as silver sulphate. The quantitative recovery of nitrogen in the above three compounds with the molten ALS flux decomposition system can be obtained by the Kjeldahl method.

  20. Two-dimensional Zn(II) and one-dimensional Co(II) coordination polymers based on benzene-1,4-dicarboxylate and pyridine ligands.

    PubMed

    Zhou, Li-Juan; Han, Chang-Bao; Wang, Yu-Ling

    2016-02-01

    Coordination polymers constructed from metal ions and organic ligands have attracted considerable attention owing to their diverse structural topologies and potential applications. Ligands containing carboxylate groups are among the most extensively studied because of their versatile coordination modes. Reactions of benzene-1,4-dicarboxylic acid (H2BDC) and pyridine (py) with Zn(II) or Co(II) yielded two new coordination polymers, namely, poly[(μ4-benzene-1,4-dicarboxylato-κ(4)O:O':O'':O''')(pyridine-κN)zinc(II)], [Zn(C8H4O2)(C5H5N)]n, (I), and catena-poly[aqua(μ3-benzene-1,4-dicarboxylato-κ(3)O:O':O'')bis(pyridine-κN)cobalt(II)], [Co(C8H4O2)(C5H5N)2(H2O)]n, (II). In compound (I), the Zn(II) cation is five-coordinated by four carboxylate O atoms from four BDC(2-) ligands and one pyridine N atom in a distorted square-pyramidal coordination geometry. Four carboxylate groups bridge two Zn(II) ions to form centrosymmetric paddle-wheel-like Zn2(μ2-COO)4 units, which are linked by the benzene rings of the BDC(2-) ligands to generate a two-dimensional layered structure. The two-dimensional layer is extended into a three-dimensional supramolecular structure with the help of π-π stacking interactions between the aromatic rings. Compound (II) has a one-dimensional double-chain structure based on Co2(μ2-COO)2 units. The Co(II) cations are bridged by BDC(2-) ligands and are octahedrally coordinated by three carboxylate O atoms from three BDC(2-) ligands, one water O atom and two pyridine N atoms. Interchain O-H...O hydrogen-bonding interactions link these chains to form a three-dimensional supramolecular architecture. PMID:26846498

  1. Lanthanide-Potassium Biphenyl-3,3'-disulfonyl-4,4'-dicarboxylate Frameworks: Gas Sorption, Proton Conductivity, and Luminescent Sensing of Metal Ions.

    PubMed

    Zhou, Li-Juan; Deng, Wei-Hua; Wang, Yu-Ling; Xu, Gang; Yin, Shun-Gao; Liu, Qing-Yan

    2016-06-20

    A novel sulfonate-carboxylate ligand of biphenyl-3,3'-disulfonyl-4,4'-dicarboxylic acid (H4-BPDSDC) and its lanthanide-organic frameworks {[LnK(BPDSDC)(DMF)(H2O)]·x(solvent)}n (JXNU-2, where JXNU denotes Jiangxi Normal University, DMF indicates dimethylformamide, and Ln = Sm(3+), Eu(3+), and Pr(3+)) were synthesized and structurally characterized. The three isomorphous lanthanide compounds feature three-dimensional frameworks constructed from one-dimensional (1D) rod-shaped heterometallic Ln-K secondary building units and are an illustration of a Kagome-like lattice with large 1D hexagonal channels and small 1D trigonal channels. The porous material of the representive JXNU-2(Sm) has an affinity to quadrupolar molecules such as CO2 and C2H2. In addition, the JXNU-2(Sm) compound exhibits humidity- and temperature-dependent proton conductivity with a large value of 1.11 × 10(-3) S cm(-1) at 80 °C and 98% relative humidity. The hydrophilic sulfonate group on the surface of channels facilitates enrichment of the solvate water molecules in the channels, which enhances the proton conductivity of this material. Moreover, the JXNU-2(Eu) material with the characteristic bright red color shows the potential for recognition of K(+) and Fe(3+) ions. The enhancing Eu(3+) luminescence with the K(+) ion and quenching Eu(3+) luminescence with the Fe(3+) ion can be associated with the functional groups of the organic ligand. PMID:27267985

  2. Assignment of the gene coding for the human high-affinity glutamate transporter EAAC1 to 9p24: Potential role in dicarboxylic aminoaciduria and neurodegenerative disorders

    SciTech Connect

    Smith, C.P.; Kanai, Y.; Stelzner, M.; Hediger, M.A.; Weremowicz, S.; Morton, C.C. )

    1994-03-15

    Functional defects of high-affinity glutamate transporters have been implicated in the pathophysiology of neurodegenerative diseases such as amyotrophic lateral sclerosis. In small intestine and kidney, in which the high-affinity glutamate transporter mediates net absorption of glutamate and aspartate across epithelial cells, an inborn error of glutamate transport is thought to cause dicarboxylic aminoaciduria. This disorder is characterized by increased urinary excretion of glutamate and aspartate and is, in general, associated with neurologic and developmental abnormalities. Recently, the authors isolated a cDNA encoding a high-affinity glutamate transporter (EAAC1) that also transports aspartate but not other amino acids. EAAC1 is ubiquitously expressed throughout the body, particularly in brain (neurons), intestine, and kidney. Here, the authors present mapping of the chromosome location of EAAC1 using Southern analysis of a panel of human/rodent somatic cell hybrids and fluorescence in situ hybridization (FISH). Southern analysis of EcoRI-digested DNA gave bands at 6.5, 5.6, 5.1, and 1.2 kb for human genomic DNA; 7.5 kb for mouse genomic DNA; and 7.3, 3.2, and 1 kb for hamster genomic DNA. All four human EAAC1-specific bands were observed in the lane corresponding to the human/Chinese hamster hybrid containing chromosome 9 but not in lanes corresponding to any other hybrid. Because the human/Chinese hamster hybrid is the only one retaining chromosome 9, this result unambiguously assigns human EAAC1 to chromosome 9. For precise chromosome assignment of the human EAAC1 gene, they employed FISH. Map position of the EAAC1 probe was assigned by visual inspection of the fluorescent signal on the DAPI-stained metaphase chromosomes. The human EAAC1 gene was assigned to 9p24.

  3. Stable carbon isotopic compositions of organic acids in total suspended particles and dusts from Guangzhou, China

    NASA Astrophysics Data System (ADS)

    Ma, Shexia; Peng, Ping'an; Song, Jianzhong; Zhao, Jinping; He, Lulu; Sheng, Guoying; Fu, Jiamo

    2010-10-01

    Stable carbon isotopic compositions of individual organic acids were determined in total suspended particles and dusts from Guangzhou. The δ 13C values of high molecular weight n-alkanoic acids (C 20-C 28) varied from -34.1‰ to -32.4‰ and tended to be heavier in summer and lighter in winter. These δ 13C values indicate that high molecular weight n-alkanoic acids were derived mainly from emission by C 3 plants. Reduced biological synthesis of high molecular weight n-alkanoic acids in winter may be the reason for the light carbon isotopic composition. The δ 13C values of low molecular weight n-alkanoic acids (C 10-C 18) changed from -31.7‰ to -30.3‰ and exhibited a reverse seasonal trend, i.e., heavier in winter and lighter in summer. Slightly heavier δ 13C values of low molecular weight n-alkanoic acids than those of high molecular weight n-alkanoic acids suggested that they may be emitted from blended sources, e.g., anthropogenic sources and vegetation waxes. Lighter δ 13C values in summer may be attributed to relatively low anthropogenic sources and high botanic sources in summer. Dicarboxylic acids and aromatic acids have been proposed as secondary products from photochemical degradation. The average δ 13C values of dicarboxylic acids and aromatic acids were heavier, and ranged from -25.2‰ to -22.9‰ and from -30.0‰ to -27.6‰, respectively. Both dicarboxylic acids and aromatic acids displayed the same temporal variations in the δ 13C values, i.e., negative δ 13C in the summer samples and positive in the winter samples, which may be controlled by photochemical reactions; they are generally severe in winter in Guangzhou under the monsoon weather system. The heaviest δ 13C values were observed in dicarboxylic acids, indicating that dicarboxylic acids were formed by fast and more complete oxidation reactions. These results indicate that the stable carbon isotopic composition of organic acids may provide important information about sources and

  4. Vascular effects of the Mediterranean diet-part II: role of omega-3 fatty acids and olive oil polyphenols.

    PubMed

    Scoditti, Egeria; Capurso, Cristiano; Capurso, Antonio; Massaro, Marika

    2014-12-01

    The lower occurrence of cardiovascular disease and cancer in populations around the Mediterranean basin as detected in the 1950s was correctly attributed to the peculiar dietary habits of those populations. Essentially, until the mid-20th century, typical Mediterranean diets were rich in fruits, vegetables, legumes, whole-wheat bread, nuts, fish, and, as a common culinary trait, the routine use of extra-virgin olive oil. Nowadays, the regular adoption of such dietary patterns is still thought to result in healthful benefits. Such patterns ensure the assumption of molecules with antioxidant and anti-inflammatory actions, among which ω-3 polyunsaturated fatty acids (PUFAs), ω-9 monounsaturated fatty acids (oleic acid), and phenolic compounds. The aim of this review is to provide an update of the vasculo-protective pathways mediated by ω-3 PUFAs and polyphenols in the context of the modern Mediterranean dietary habits, including the possible cross-talk and synergy between these typical components. This review complements a parallel one focusing on the role of dietary nitrates and alimentary fats.

  5. High temperature abatement of acid gases from waste incineration. Part I: experimental tests in full scale plants.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Rigamonti, Lucia; Marras, Roberto; Grosso, Mario

    2015-02-01

    In recent years, several waste-to-energy plants in Italy have experienced an increase of the concentration of acid gases (HCl, SO2 and HF) in the raw gas. This is likely an indirect effect of the progressive decrease of the amount of treated municipal waste, which is partially replaced by commercial waste. The latter is characterised by a higher variability of its chemical composition because of the different origins, with possible increase of the load of halogen elements such as chlorine (Cl) and fluorine (F), as well as of sulphur (S). A new dolomitic sorbent was then tested in four waste-to-energy plants during standard operation as a pre-cleaning stage, to be directly injected at high temperature in the combustion chamber. For a sorbent injection of about 6 kg per tonne of waste, the decrease of acid gases concentration downstream the boiler was in the range of 7-37% (mean 23%) for HCl, 34-95% (mean 71%) for SO2 and 39-80% (mean 63%) for HF. This pre-abatement of acid gases allowed to decrease the feeding rate of the traditional low temperature sorbent (sodium bicarbonate in all four plants) by about 30%. Furthermore, it was observed by the plant operators that the sorbent helps to keep the boiler surfaces cleaner, with a possible reduction of the fouling phenomena and a consequent increase of the specific energy production. A preliminary quantitative estimate was carried out in one of the four plants. PMID:25465511

  6. High temperature abatement of acid gases from waste incineration. Part I: experimental tests in full scale plants.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Rigamonti, Lucia; Marras, Roberto; Grosso, Mario

    2015-02-01

    In recent years, several waste-to-energy plants in Italy have experienced an increase of the concentration of acid gases (HCl, SO2 and HF) in the raw gas. This is likely an indirect effect of the progressive decrease of the amount of treated municipal waste, which is partially replaced by commercial waste. The latter is characterised by a higher variability of its chemical composition because of the different origins, with possible increase of the load of halogen elements such as chlorine (Cl) and fluorine (F), as well as of sulphur (S). A new dolomitic sorbent was then tested in four waste-to-energy plants during standard operation as a pre-cleaning stage, to be directly injected at high temperature in the combustion chamber. For a sorbent injection of about 6 kg per tonne of waste, the decrease of acid gases concentration downstream the boiler was in the range of 7-37% (mean 23%) for HCl, 34-95% (mean 71%) for SO2 and 39-80% (mean 63%) for HF. This pre-abatement of acid gases allowed to decrease the feeding rate of the traditional low temperature sorbent (sodium bicarbonate in all four plants) by about 30%. Furthermore, it was observed by the plant operators that the sorbent helps to keep the boiler surfaces cleaner, with a possible reduction of the fouling phenomena and a consequent increase of the specific energy production. A preliminary quantitative estimate was carried out in one of the four plants.

  7. Amino acids as co-amorphous stabilizers for poorly water soluble drugs--Part 1: preparation, stability and dissolution enhancement.

    PubMed

    Löbmann, Korbinian; Grohganz, Holger; Laitinen, Riikka; Strachan, Clare; Rades, Thomas

    2013-11-01

    Poor aqueous solubility of an active pharmaceutical ingredient (API) is one of the most pressing problems in pharmaceutical research and development because up to 90% of new API candidates under development are poorly water soluble. These drugs usually have a low and variable oral bioavailability, and therefore an unsatisfactory therapeutic effect. One of the most promising approaches to increase dissolution rate and solubility of these drugs is the conversion of a crystalline form of the drug into its respective amorphous form, usually by incorporation into hydrophilic polymers, forming glass solutions. However, this strategy only led to a small number of marketed products usually because of inadequate physical stability of the drug (crystallization). In this study, we investigated a fundamentally different approach to stabilize the amorphous form of drugs, namely the use of amino acids as small molecular weight excipients that form specific molecular interactions with the drug resulting in co-amorphous forms. The two poorly water soluble drugs carbamazepine and indomethacin were combined with amino acids from the binding sites of the biological receptors of these drugs. Mixtures of drug and the amino acids arginine, phenylalanine, tryptophan and tyrosine were prepared by vibrational ball milling. Solid-state characterization with X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) revealed that the various blends could be prepared as homogeneous, single phase co-amorphous formulations indicated by the appearance of an amorphous halo in the XRPD diffractograms and a single glass transition temperature (Tg) in the DSC measurements. In addition, the Tgs of the co-amorphous mixtures were significantly increased over those of the individual drugs. The drugs remained chemically stable during the milling process and the co-amorphous formulations were generally physically stable over at least 6 months at 40 °C under dry conditions. The

  8. Ascorbic acid partly antagonizes resveratrol mediated heme oxygenase-1 but not paraoxonase-1 induction in cultured hepatocytes - role of the redox-regulated transcription factor Nrf2

    PubMed Central

    2011-01-01

    Background Both resveratrol and vitamin C (ascorbic acid) are frequently used in complementary and alternative medicine. However, little is known about the underlying mechanisms for potential health benefits of resveratrol and its interactions with ascorbic acid. Methods The antioxidant enzymes heme oxygenase-1 and paraoxonase-1 were analysed for their mRNA and protein levels in HUH7 liver cells treated with 10 and 25 μmol/l resveratrol in the absence and presence of 100 and 1000 μmol/l ascorbic acid. Additionally the transactivation of the transcription factor Nrf2 and paraoxonase-1 were determined by reporter gene assays. Results Here, we demonstrate that resveratrol induces the antioxidant enzymes heme oxygenase-1 and paraoxonase-1 in cultured hepatocytes. Heme oxygenase-1 induction by resveratrol was accompanied by an increase in Nrf2 transactivation. Resveratrol mediated Nrf2 transactivation as well as heme oxygenase-1 induction were partly antagonized by 1000 μmol/l ascorbic acid. Conclusions Unlike heme oxygenase-1 (which is highly regulated by Nrf2) paraoxonase-1 (which exhibits fewer ARE/Nrf2 binding sites in its promoter) induction by resveratrol was not counteracted by ascorbic acid. Addition of resveratrol to the cell culture medium produced relatively low levels of hydrogen peroxide which may be a positive hormetic redox-signal for Nrf2 dependent gene expression thereby driving heme oxygenase-1 induction. However, high concentrations of ascorbic acid manifold increased hydrogen peroxide production in the cell culture medium which may be a stress signal thereby disrupting the Nrf2 signalling pathway. PMID:21199573

  9. Mineral Dissolution and Metal Mobility From Rhizosphere and Non-rhizosphere Soils by Low Molecular Weight Organic Acids

    NASA Astrophysics Data System (ADS)

    Little, D. A.; Field, J. B.; Welch, S. A.

    2005-12-01

    This research is part of an ongoing investigation of micro-biogeochemistry in the rhizosphere of co-occurring Eucalyptus mannifera and Acacia falciformis on the Southern Tablelands of New South Wales, Australia. While there is still considerable controversy in the literature regarding the roles of low molecular weight organic acids in soil processes there is growing evidence suggesting low molecular weight compounds, especially di-carboxylic acids, have large impacts on mineral dissolution and metal mobility in the rhizosphere. Rhizosphere and non-rhizosphere samples from adjacent E. mannifera and A. falciformis trees were subjected to four separate treatments in sets of 3 replicates; +oxalic acid, +malic acid, +citric acid or +NaCl control solution. These three acids were chosen because they are produced by rhizosphere species and they form stable complexes with nutrient elements such as Phosphorus (P), Iron (Fe), and Calcium (Ca). Solution samples were collected at day 1, day 8 and day 15 for pH measurement and analysed for major and trace elements by ICP-AES and ICP-MS. The results of the preliminary dissolution experiments show that milli-molar concentrations of individual organic acids, malate and oxalate, and in particular citrate, greatly increase the release of major and trace metals to solution compared to inorganic controls. Concentrations of Al and Fe in organic acid solutions were up to 10 times greater than in the inorganic controls. Si concentrations were a factor of 2-5 greater in the organic acid solutions, suggesting preferential weathering of Fe and Al oxyhydroxide phases rather than primary silicate minerals. Dissolution of elements such as Si, Al and Fe from rhizosphere soils were about twice that observed from non-rhizosphere soils, further supporting this. Interestingly Ti and Zr, which are usually considered to be immobile during chemical weathering and are not usually taken up by plants, were also mobilised from the rhizosphere soils

  10. Profiling of Gallic and Ellagic Acid Derivatives in Different Plant Parts of Terminalia arjuna by HPLC-ESI-QTOF-MS/MS.

    PubMed

    Singh, Awantika; Bajpai, Vikas; Kumar, Sunil; Sharma, Kulwant Rai; Kumara, Brijesh

    2016-02-01

    Terminalia arjuna is a medicinal plant used in ethnomedicine and the codified traditional medicine. A number of active constituents are reported, but there is no information on the whole range of gallic and ellagic acid derivatives present in this plant A rapid and sensitive analytical method was developed using reverse phase high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS) for qualitative analysis to determine the array of bioactive phytochemicals and their variations in different plant parts viz. bark, unripe fruit, ripe fruit, leaf, root and stem. Separation was performed on a Thermo Betasil C8 column (250 mm x 4.5 mm, 5 µm) with a mobile phase consisted of 0.1% formic acid aqueous solution and acetonitrile at a flow rate of 0.5 mL/min in 55 min. A wide range of constituents of T. arjuna were characterized and broadly grouped as 27 gallic acid and 52 ellagic acid derivatives.

  11. Profiling of Gallic and Ellagic Acid Derivatives in Different Plant Parts of Terminalia arjuna by HPLC-ESI-QTOF-MS/MS.

    PubMed

    Singh, Awantika; Bajpai, Vikas; Kumar, Sunil; Sharma, Kulwant Rai; Kumara, Brijesh

    2016-02-01

    Terminalia arjuna is a medicinal plant used in ethnomedicine and the codified traditional medicine. A number of active constituents are reported, but there is no information on the whole range of gallic and ellagic acid derivatives present in this plant A rapid and sensitive analytical method was developed using reverse phase high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS) for qualitative analysis to determine the array of bioactive phytochemicals and their variations in different plant parts viz. bark, unripe fruit, ripe fruit, leaf, root and stem. Separation was performed on a Thermo Betasil C8 column (250 mm x 4.5 mm, 5 µm) with a mobile phase consisted of 0.1% formic acid aqueous solution and acetonitrile at a flow rate of 0.5 mL/min in 55 min. A wide range of constituents of T. arjuna were characterized and broadly grouped as 27 gallic acid and 52 ellagic acid derivatives. PMID:27032211

  12. Computational study on the acidic constants of chiral Brønsted acids in dimethyl sulfoxide.

    PubMed

    Yang, Chen; Xue, Xiao-Song; Li, Xin; Cheng, Jin-Pei

    2014-05-16

    The pK(a) values of a series of chiral Brønsted acids, including N-triflylphosphoramides, bis(sulfonyl)imides, bis(sulfuryl)imides, dicarboxylic acids, sulfonic acids, and N-phosphinyl phosphoramides, were predicted by using the SMD/M06-2x/6-311++G(2df,2p)//B3LYP/6-31+G(d) method in DMSO. The results revealed that the calculated pKa values ranged from -9.06 to 12.18 for different types of acids. The influence of acidic strength on reactivity and stereoselectivity was discussed using the calculated acidity data. Given that the choice of catalyst with appropriate acidity is the primary condition, several new catalyst candidates were designed by calculating corresponding pK(a) values of parent acids.

  13. Theoretical study of the hydrolysis mechanism of 2-pyrone-4,6-dicarboxylate (PDC) catalyzed by LigI.

    PubMed

    Zhang, Shujun; Ma, Guangcai; Liu, Yongjun; Ling, Baoping

    2015-09-01

    2-Pyrone-4,6-dicarboxylate lactonase (LigI) is the first identified enzyme from amidohydrolase superfamily that does not require a divalent metal ion for catalytic activity. It catalyzes the reversible hydrolysis of 2-pyrone-4,6-dicarboxylate (PDC) to 4-oxalomesaconate (OMA) and 4-carboxy-2-hydroxymuconate (CHM) in the degradation of lignin. In this paper, a combined quantum mechanics and molecule mechanics (QM/MM) approach was employed to study the reaction mechanism of LigI from Sphingomonas paucimobilis. According to the results of our calculations, the whole catalytic reaction contains three elementary steps, including the nucleophilic attack, the cleavage of CO of lactone (substrate) and the intramolecular proton transfer. The intermediate has two intramolecular proton transfer pathways, due to which, two final hydrolysis products can be obtained. The energy profile indicates that 4-carboxy-2-hydroxymuconate (CHM) is the main hydrolysis product, therefore, the isomerization between 4-carboxy-2-hydroxymuconate (CHM) and 4-oxalomesaconate (OMA) is suggested to occur in solvent. During the catalytic reaction, residue Asp248 acts as a general base to activate the hydrolytic water molecule. Although His31, His33 and His180 do not directly participate in the chemical process, they play assistant roles by forming electrostatic interactions with the substrate and its involved species in activating the carbonyl group of the substrate and stabilizing the intermediates and transition states.

  14. Monitoring the formation of carbide crystal phases during the thermal decomposition of 3d transition metal dicarboxylate complexes

    SciTech Connect

    Huba, ZJ; Carpenter, EE

    2014-06-06

    Single molecule precursors can help to simplify the synthesis of complex alloys by minimizing the amount of necessary starting reagents. However, single molecule precursors are time consuming to prepare with very few being commercially available. In this study, a simple precipitation method is used to prepare Fe, Co, and Ni fumarate and succinate complexes. These complexes were then thermally decomposed in an inert atmosphere to test their efficiency as single molecule precursors for the formation of metal carbide phases. Elevated temperature X-ray diffraction was used to identify the crystal phases produced upon decomposition of the metal dicarboxylate complexes. Thermogravimetric analysis coupled with an infrared detector was used to identify the developed gaseous decomposition products. All complexes tested showed a reduction from the starting M2+ oxidation state to the M oxidation state, upon decomposition. Also, each complex tested showed CO2 and H2O as gaseous decomposition products. Nickel succinate, iron succinate, and iron fumarate complexes were found to form carbide phases upon decomposition. This proves that transition metal dicarboxylate salts can be employed as efficient single molecule precursors for the formation of metal carbide crystal phases.

  15. Chemical constituents of Malagasy liverworts, part II: mastigophoric acid methyl ester of biogenetic interest from Mastigophora diclados (Lepicoleaceae Subf. Mastigophoroideae).

    PubMed

    Harinantenaina, Liva; Asakawa, Yoshinori

    2004-11-01

    In the course of our chemotaxonomic study of the liverworts growing in Madagascar, mastigophoric acid methyl ester, along with eleven known compounds were isolated from Mastigophora diclados. Isolated metabolites showed that the Malagasy Mastigophora is more related to the samples from Borneo and Japan than to the Taiwanese or Malaysian ones. The biosynthesis of the herbertane type sesquiterpenoids from Mastigophora diclados is suggested to be similar to those found in the genus Herbertus. The herbertane-type sesquiterpenoids were screened for Staphylococcus aureus strain inhibition.

  16. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 3: Michael addition reactions and miscellaneous transformations.

    PubMed

    Aceña, José Luis; Sorochinsky, Alexander E; Soloshonok, Vadim

    2014-09-01

    The major goal of this review is a critical discussion of the literature data on asymmetric synthesis of α-amino acids via Michael addition reactions involving Ni(II)-complexes of amino acids. The material covered is divided into two conceptually different groups dealing with applications of: (a) Ni(II)-complexes of glycine as C-nucleophiles and (b) Ni(II)-complexes of dehydroalanine as Michael acceptors. The first group is significantly larger and consequently subdivided into four chapters based on the source of stereocontrolling element. Thus, a chiral auxiliary can be used as a part of nucleophilic glycine Ni(II) complex, Michael acceptor or both, leading to the conditions of matching vs. mismatching stereochemical preferences. The particular focus of the review is made on the practical aspects of the methodology under discussion and mechanistic considerations.

  17. Dicarboxylate-controlled three Zn(II) coordination polymers incorporating flexible 1,2-bis(imidazol-1‧-yl)ethane ligand: Syntheses, structures, thermal stabilities and photoluminescent properties

    NASA Astrophysics Data System (ADS)

    Hao, Hong-Jun; Sun, Di; Liu, Fu-Jing; Huang, Rong-Bin; Zheng, Lan-Sun

    2012-03-01

    Three mixed-ligand Zn(II) coordination polymers (CPs) of the formula {[Zn2(bime)2(adip)2]ṡ(H2O)5}n (1), {[Zn(bime)(ipa)]ṡ(H2O)3}n (2), {[Zn(bime)(tpa)]ṡ(H2O)ṡ(CH3OH)}n (3) (bime = 1,2-bis(imidazol-1'-yl)ethane, H2adip = adipic acid, H2ipa = isophthalic acid and H2tpa = terephthalic acid) were synthesized. All CPs have been characterized by element analysis, powder X-ray diffraction (PXRD), IR and X-ray single-crystal diffraction. Complexes 1 and 2 exhibit similar wavy two-dimensional (2D) sheets with 44-sql topology. Compared to 1, complex 2 contains a larger window owing to the different conformation of bime ligand. In both 1 and 2, we observed 1D water chain filling in the 44-sql net. In 3, the bime acts as a bidentate ligand and the tpa adopts a μ2-η1,η1 coordinated mode which links the Zn(II) ions to form a 2D 63-hcb net. The results suggest that the dicarboxylates play crucial roles in the formation of the different structures. In addition, the thermal stabilities and the photoluminescence properties of them were also investigated.

  18. Improved amber and opal suppressor tRNAs for incorporation of unnatural amino acids in vivo. Part 1: Minimizing misacylation

    PubMed Central

    Rodriguez, Erik A.; Lester, Henry A.; Dougherty, Dennis A.

    2007-01-01

    The incorporation of unnatural amino acids site-specifically is a valuable technique for structure–function studies, incorporation of biophysical probes, and determining protein–protein interactions. THG73 is an amber suppressor tRNA used extensively for the incorporation of >100 different residues in over 20 proteins, but under certain conditions THG73 is aminoacylated in vivo by endogenous aminoacyl-tRNA synthetase. Similar aminoacylation is seen with the Escherichia coli Asn amber suppressor tRNA, which has also been used to incorporate UAAs in many studies. We now find that the natural amino acid placed on THG73 is Gln. Since the E. coli GlnRS recognizes positions in the acceptor stem, we made several acceptor stem mutations in the second to fourth positions on THG73. All mutations reduce aminoacylation in vivo and allow for the selection of highly orthogonal tRNAs. To show the generality of these mutations, we created opal suppressor tRNAs that show less aminoacylation in Xenopus oocytes relative to THG73. We have created a library of Tetrahymena thermophila Gln amber suppressor tRNAs that will be useful for determining optimal suppressor tRNAs for use in other eukaryotic cells. PMID:17698638

  19. Surface functionalization of bioactive glasses with natural molecules of biological significance, Part I: Gallic acid as model molecule

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Ferraris, Sara; Prenesti, Enrico; Verné, Enrica

    2013-12-01

    Gallic acid (3,4,5-trihydroxybenzoic acid, GA) and its derivatives are a group of biomolecules (polyphenols) obtained from plants. They have effects which are potentially beneficial to heath, for example they are antioxidant, anticarcinogenic and antibacterial, as recently investigated in many fields such as medicine, food and plant sciences. The main drawbacks of these molecules are both low stability and bioavailability. In this research work the opportunity to graft GA to bioactive glasses is investigated, in order to deliver the undamaged biological molecule into the body, using the biomaterial surfaces as a localized carrier. GA was considered for functionalization since it is a good model molecule for polyphenols and presents several interesting biological activities, like antibacterial, antioxidant and anticarcinogenic properties. Two different silica based bioactive glasses (SCNA and CEL2), with different reactivity, were employed as substrates. UV photometry combined with the Folin&Ciocalteu reagent was adopted to test the concentration of GA in uptake solution after functionalization. This test verified how much GA consumption occurred with surface modification and it was also used on solid samples to test the presence of GA on functionalized glasses. XPS and SEM-EDS techniques were employed to characterize the modification of material surface properties and functional group composition before and after functionalization.

  20. Surface grafted chitosan gels. Part I. Molecular insight into the formation of chitosan and poly(acrylic acid) multilayers.

    PubMed

    Liu, Chao; Thormann, Esben; Claesson, Per M; Tyrode, Eric

    2014-07-29

    Composite polyelectrolyte multilayers of chitosan and low molecular weight poly(acrylic acid) (PAA) have been assembled by sequential adsorption as a first step toward building a surface anchored chitosan gel. Silane chemistry was used to graft the first chitosan layer to prevent film detachment and decomposition. The assembly process is characterized by nonlinear growth behavior, with different adsorption kinetics for chitosan and PAA. In situ analysis of the multilayer by means of surface sensitive total internal reflection Raman (TIRR) spectroscopy, combined with target factor analysis of the spectra, provided information regarding composition, including water content, and ionization state of weak acidic and basic groups present in the thin composite film. Low molecular weight PAA, mainly in its protonated form, diffuses into and out of the composite film during adsorption and rinsing steps. The higher molecular weight chitosan shows a similar behavior, although to a much lower extent. Our data demonstrate that the charged monomeric units of chitosan are mainly compensated by carboxylate ions from PAA. Furthermore, the morphology and mechanical properties of the multilayers were investigated in situ using atomic force microscopy operating in PeakForce tapping mode. The multilayer consists of islands that grow in lateral dimension and height during the build-up process, leading to close to exponentially increasing roughness with deposition number. Both diffusion in and out of at least one of the two components (PAA) and the island-like morphology contribute to the nonlinear growth of chitosan/PAA multilayers.

  1. 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.

  2. The possible role of hydrothermal vents in chemical evolution: Succinic acid radiolysis and thermolysis

    NASA Astrophysics Data System (ADS)

    Cruz-Castañeda, J.; Colín-García, M.; Negrón-Mendoza, A.

    2014-07-01

    In this research, the behavior under a high radiation field or high temperature of succinic acid, a dicarboxylic acid clue in metabolic routes, is studied. For this purpose, the molecule was irradiated with gamma rays in oxygen-free aqueous solutions, and the thermal decomposition was studied in a static system at temperatures up to 90 °C, simulating a white hydrothermal vent. Our results indicate that a succinic acid is a relatively stable compound under irradiation. The gamma radiolysis yields carbon dioxide and di- and tricarboxylic acids such as malonic, carboxysuccinic, and citric acids. The main products obtained by the thermal treatment were CO2 and propionic acid.

  3. A two-dimensional mixed-valence Cu(II)/Cu(I) coordination polymer constructed from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate.

    PubMed

    Zhang, Li Yang; Lu, Li Ping; Feng, Si Si

    2016-08-01

    Coordination polymers are a thriving class of functional solid-state materials and there have been noticeable efforts and progress toward designing periodic functional structures with desired geometrical attributes and chemical properties for targeted applications. Self-assembly of metal ions and organic ligands is one of the most efficient and widely utilized methods for the construction of CPs under hydro(solvo)thermal conditions. 2-(Pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate (HPIDC(2-)) has been proven to be an excellent multidentate ligand due to its multiple deprotonation and coordination modes. Crystals of poly[aquabis[μ3-5-carboxy-2-(pyridin-3-yl)-1H-imidazole-4-carboxylato-κ(5)N(1),O(5):N(3),O(4):N(2)]copper(II)dicopper(I)], [Cu(II)Cu(I)2(C10H5N3O4)2(H2O)]n, (I), were obtained from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylic acid (H3PIDC) and copper(II) chloride under hydrothermal conditions. The asymmetric unit consists of one independent Cu(II) ion, two Cu(I) ions, two HPIDC(2-) ligands and one coordinated water molecule. The Cu(II) centre displays a square-pyramidal geometry (CuN2O3), with two N,O-chelating HPIDC(2-) ligands occupying the basal plane in a trans geometry and one O atom from a coordinated water molecule in the axial position. The Cu(I) atoms adopt three-coordinated Y-shaped coordinations. In each [CuN2O] unit, deprotonated HPIDC(2-) acts as an N,O-chelating ligand, and a symmetry-equivalent HPIDC(2-) ligand acts as an N-atom donor via the pyridine group. The HPIDC(2-) ligands in the polymer serve as T-shaped 3-connectors and adopt a μ3-κ(2)N,O:κ(2)N',O':κN''-coordination mode, linking one Cu(II) and two Cu(I) cations. The Cu cations are arranged in one-dimensional -Cu1-Cu2-Cu3- chains along the [001] direction. Further crosslinking of these chains by HPIDC(2-) ligands along the b axis in a -Cu2-HPIDC(2-)-Cu3-HPIDC(2-)-Cu1- sequence results in a two-dimensional polymer in the (100) plane. The resulting (2,3)-connected net has a

  4. A two-dimensional mixed-valence Cu(II)/Cu(I) coordination polymer constructed from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate.

    PubMed

    Zhang, Li Yang; Lu, Li Ping; Feng, Si Si

    2016-08-01

    Coordination polymers are a thriving class of functional solid-state materials and there have been noticeable efforts and progress toward designing periodic functional structures with desired geometrical attributes and chemical properties for targeted applications. Self-assembly of metal ions and organic ligands is one of the most efficient and widely utilized methods for the construction of CPs under hydro(solvo)thermal conditions. 2-(Pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate (HPIDC(2-)) has been proven to be an excellent multidentate ligand due to its multiple deprotonation and coordination modes. Crystals of poly[aquabis[μ3-5-carboxy-2-(pyridin-3-yl)-1H-imidazole-4-carboxylato-κ(5)N(1),O(5):N(3),O(4):N(2)]copper(II)dicopper(I)], [Cu(II)Cu(I)2(C10H5N3O4)2(H2O)]n, (I), were obtained from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylic acid (H3PIDC) and copper(II) chloride under hydrothermal conditions. The asymmetric unit consists of one independent Cu(II) ion, two Cu(I) ions, two HPIDC(2-) ligands and one coordinated water molecule. The Cu(II) centre displays a square-pyramidal geometry (CuN2O3), with two N,O-chelating HPIDC(2-) ligands occupying the basal plane in a trans geometry and one O atom from a coordinated water molecule in the axial position. The Cu(I) atoms adopt three-coordinated Y-shaped coordinations. In each [CuN2O] unit, deprotonated HPIDC(2-) acts as an N,O-chelating ligand, and a symmetry-equivalent HPIDC(2-) ligand acts as an N-atom donor via the pyridine group. The HPIDC(2-) ligands in the polymer serve as T-shaped 3-connectors and adopt a μ3-κ(2)N,O:κ(2)N',O':κN''-coordination mode, linking one Cu(II) and two Cu(I) cations. The Cu cations are arranged in one-dimensional -Cu1-Cu2-Cu3- chains along the [001] direction. Further crosslinking of these chains by HPIDC(2-) ligands along the b axis in a -Cu2-HPIDC(2-)-Cu3-HPIDC(2-)-Cu1- sequence results in a two-dimensional polymer in the (100) plane. The resulting (2,3)-connected net has a

  5. Assembly of Cerium(III) 2,2'-Bipyridine-5,5'-dicarboxylate-based Metal–Organic Frameworks by Solvent Tuning

    SciTech Connect

    Ayhan, Ozan; Malaestean, Iurie L.; Ellern, Arkady; van Leusen, Jan; Baca, Svetlana G.; Kögerler, Paul

    2014-07-02

    Two cerium(III) 2,2'-bipyridine-5,5'-dicarboxylate-based 3D coordination networks highlight the ability of CeIII ions to adopt different coordination environments upon subtle changes to the reaction conditions, producing metal-organic frameworks that integrate varying crystal solvent contents.

  6. 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.

  7. Biooxidation of fatty acid distillates to dibasic acids by a mutant of Candida tropicalis.

    PubMed

    Gangopadhyay, Sarbani; Nandi, Sumit; Ghosh, Santinath

    2006-01-01

    Fatty acid distillates (FADs) produced during physical refining of vegetable oil contains large amount of free fatty acid. A mutant of Candida tropicalis (M20) obtained after several stages of UV mutation are utilized to produce dicarboxylic acids (DCAs) from the fatty acid distillates of rice bran, soybean, coconut, palm kernel and palm oil. Initially, fermentation study was carried out in shake flasks for 144 h. Products were isolated and identified by GLC analysis. Finally, fermentation was carried out in a 2 L jar fermenter, which yielded 62 g/L and 48 g/L of total dibasic acids from rice bran oil fatty acid distillate and coconut oil fatty acid distillate respectively. FADs can be effectively utilized to produce DCAs of various chain lengths by biooxidation process. PMID:17693693

  8. IUPAC-NIST Solubility Data Series. 90. Hydroxybenzoic Acid Derivatives in Binary, Ternary, and Multicomponent Systems. Part I. Hydroxybenzoic Acids, Hydroxybenzoates, and Hydroxybenzoic Acid Salts in Water and Aqueous Systems

    NASA Astrophysics Data System (ADS)

    Goto, Rensuke; Fukuda, Hiroshi; Königsberger, Erich; Königsberger, Lan-Chi

    2011-03-01

    The solubility data for well-defined binary, ternary, and multicomponent systems of solid-liquid type are reviewed. One component, which is 2-, 3-, and 4-hydroxybenzoic acids, 4-hydroxybenzoate alkyl esters (parabens), or hydroxybenzoic acid salts, is in the solid state at room temperature and another component is liquid water, meaning that all of the systems are aqueous solutions. The ternary or multicomponent systems include organic substances of various classes (hydrocarbons of several structural types, halogenated hydrocarbons, alcohols, acids, ethers, esters, amides, and surfactants) or inorganic substances. Systems reported in the primary literature from 1898 through 2000 are compiled. For seven systems, sufficient binary data for hydroxybenzoic acids or parabens in water are available to allow critical evaluation. Almost all data are expressed as mass and mole fractions as well as the originally reported units, while some data are expressed as molar concentration.

  9. The profile of volatile compounds in the outer and inner parts of broiled pork neck is strongly influenced by the acetic-acid marination conditions.

    PubMed

    Biller, Elżbieta; Boselli, Emanuele; Obiedziński, Mieczysław; Karpiński, Piotr; Waszkiewicz-Robak, Bożena

    2016-11-01

    Raw pork neck cutlets were marinated in an aqueous solution of acetic acid (pH4, 24h, 4°C) without (M) or with 1% (w/w) of glucose. The control (K) was formed by non-treated raw pork neck. The cutlets were then broiled (185°C, 30min). In all K cutlets, significant higher amounts of volatile compounds (VCs) were developed after broiling than the other samples. Significant more aldehydes and alcohols were present in the inner parts than in the surface. The correlation between surface and internal layers was high only for aldehydes. Marinating decreased the differences among VCs and led to the standardization of the processed meat. The addition of glucose to the marinade led to more volatile aldehydes, carboxylic acids, esters, furan, pyran, pyrazine, pyrrol and pyridine derivatives than in M samples. Several (53) specific VCs explained the differences among the surface samples related to the marinating process. However, only 16 VCs explained the variance among the inner parts. PMID:27395822

  10. Part 2. Comparison of emergency washing solutions in 70% hydrofluoric acid-burned human skin in an established ex vivo explants model

    PubMed Central

    Burgher, François; Mathieu, Laurence; Lati, Elian; Gasser, Philippe; Peno-Mazzarino, Laurent; Blomet, Joël; Hall, Alan H; Maibach, Howard I

    2011-01-01

    Background: Hydrofluoric acid (HF) is a small and partially dissociated acid (pKa 3.2), able to deeply penetrate into human skin in addition to the corrosiveness of the hydrogen ion (H+) and the toxicity of the fluoride ion (F-). However, there has been a lack of experimental studies to objectively characterize the results of human HF skin exposure decontamination. Methodology/principal findings: A previously established experimental method using a human skin explants ex vivo model (Part 1. Experimental 70% hydrofluoric acid (HF) burns: Histological observations in an established human skin explants ex vivo model) described the lesions that appeared following 70% HF penetration. Within 5min, 70% HF penetrates to the dermis. Using the same experimental conditions, a comparison study of two different washing protocols was performed: water + topical calcium gluconate (CaG) versus Hexafluorine®. In these conditions, washing for 15min with running tap water followed by topical CaG ointment only delayed burn onset, while severe tissue damage appeared later. In contrast, after washing with Hexafluorine® over 10 min, no histological lesions developed. These results are in accordance with the results of accidental human industrial case reports. Conclusion/significance: Amphoteric and hypertonic Hexafluorine® can deactivate H+ and chelate F- ions. Based on these results, it should be considered as a promising first-aid decontamination solution to prevent or minimize significant local and systemic consequences of concentrated HF skin exposures. PMID:21083510

  11. Antioxidant capacity and amino acid analysis of Caralluma adscendens (Roxb.) Haw var. fimbriata (wall.) Grav. & Mayur. aerial parts.

    PubMed

    Maheshu, Vellingiri; Priyadarsini, Deivamarudhachalam Teepica; Sasikumar, Jagathala Mahalingam

    2014-10-01

    Caralluma adscendens (Roxb.) Haw var. fimbriata (wall.) Grav. & Mayur. is a traditional food consumed as vegetable or pickle in arid regions of India and eaten during famines. In Indian traditional medicine, the plant is used to treat diabetes, inflammation and etc. The aim of this study was to evaluate the antioxidant properties (DPPH, TEAC, TAA, FRAP, OH˙ and NO˙ radical scavenging activities) of the different extracts from aerial parts. The levels of total phenolics and flavonoids of the extracts were also determined. The extracts were found to have different levels of antioxidant properties in the test models used. Methanol and water extracts had good total phenolic and flavonoid contents showed potent antioxidant and free radical scavenging activities. The antioxidant activity was correlated well with the amount of total phenolics present in the extracts. The extracts and its components may be used as an additive in food preparations and nutraceuticals. PMID:25328180

  12. Sequential Mixed Cultures: From Syngas to Malic Acid.

    PubMed

    Oswald, Florian; Dörsam, Stefan; Veith, Nicolas; Zwick, Michaela; Neumann, Anke; Ochsenreither, Katrin; Syldatk, Christoph

    2016-01-01

    Synthesis gas (syngas) fermentation using acetogenic bacteria is an approach for production of bulk chemicals like acetate, ethanol, butanol, or 2,3-butandiol avoiding the fuel vs. food debate by using carbon monoxide, carbon dioxide, and hydrogen from gasification of biomass or industrial waste gases. Suffering from energetic limitations, yields of C4-molecules produced by syngas fermentation are quite low compared with ABE fermentation using sugars as a substrate. On the other hand, fungal production of malic acid has high yields of product per gram metabolized substrate but is currently limited to sugar containing substrates. In this study, it was possible to show that Aspergilus oryzae is able to produce malic acid using acetate as sole carbon source which is a main product of acetogenic syngas fermentation. Bioreactor cultivations were conducted in 2.5 L stirred tank reactors. During the syngas fermentation part of the sequential mixed culture, Clostridium ljungdahlii was grown in modified Tanner medium and sparged with 20 mL/min of artificial syngas mimicking a composition of clean syngas from entrained bed gasification of straw (32.5 vol-% CO, 32.5 vol-% H2, 16 vol-% CO2, and 19 vol-% N2) using a microsparger. Syngas consumption was monitored via automated gas chromatographic measurement of the off-gas. For the fungal fermentation part gas sparging was switched to 0.6 L/min of air and a standard sparger. Ammonia content of medium for syngas fermentation was reduced to 0.33 g/L NH4Cl to meet the requirements for fungal production of dicarboxylic acids. Malic acid production performance of A. oryzae in organic acid production medium and syngas medium with acetate as sole carbon source was verified and gave YP∕S values of 0.28 g/g and 0.37 g/g respectively. Growth and acetate formation of C. ljungdahlii during syngas fermentation were not affected by the reduced ammonia content and 66 % of the consumed syngas was converted to acetate. The overall conversion

  13. Sequential Mixed Cultures: From Syngas to Malic Acid.

    PubMed

    Oswald, Florian; Dörsam, Stefan; Veith, Nicolas; Zwick, Michaela; Neumann, Anke; Ochsenreither, Katrin; Syldatk, Christoph

    2016-01-01

    Synthesis gas (syngas) fermentation using acetogenic bacteria is an approach for production of bulk chemicals like acetate, ethanol, butanol, or 2,3-butandiol avoiding the fuel vs. food debate by using carbon monoxide, carbon dioxide, and hydrogen from gasification of biomass or industrial waste gases. Suffering from energetic limitations, yields of C4-molecules produced by syngas fermentation are quite low compared with ABE fermentation using sugars as a substrate. On the other hand, fungal production of malic acid has high yields of product per gram metabolized substrate but is currently limited to sugar containing substrates. In this study, it was possible to show that Aspergilus oryzae is able to produce malic acid using acetate as sole carbon source which is a main product of acetogenic syngas fermentation. Bioreactor cultivations were conducted in 2.5 L stirred tank reactors. During the syngas fermentation part of the sequential mixed culture, Clostridium ljungdahlii was grown in modified Tanner medium and sparged with 20 mL/min of artificial syngas mimicking a composition of clean syngas from entrained bed gasification of straw (32.5 vol-% CO, 32.5 vol-% H2, 16 vol-% CO2, and 19 vol-% N2) using a microsparger. Syngas consumption was monitored via automated gas chromatographic measurement of the off-gas. For the fungal fermentation part gas sparging was switched to 0.6 L/min of air and a standard sparger. Ammonia content of medium for syngas fermentation was reduced to 0.33 g/L NH4Cl to meet the requirements for fungal production of dicarboxylic acids. Malic acid production performance of A. oryzae in organic acid production medium and syngas medium with acetate as sole carbon source was verified and gave YP∕S values of 0.28 g/g and 0.37 g/g respectively. Growth and acetate formation of C. ljungdahlii during syngas fermentation were not affected by the reduced ammonia content and 66 % of the consumed syngas was converted to acetate. The overall conversion

  14. Sequential Mixed Cultures: From Syngas to Malic Acid

    PubMed Central

    Oswald, Florian; Dörsam, Stefan; Veith, Nicolas; Zwick, Michaela; Neumann, Anke; Ochsenreither, Katrin; Syldatk, Christoph

    2016-01-01

    Synthesis gas (syngas) fermentation using acetogenic bacteria is an approach for production of bulk chemicals like acetate, ethanol, butanol, or 2,3-butandiol avoiding the fuel vs. food debate by using carbon monoxide, carbon dioxide, and hydrogen from gasification of biomass or industrial waste gases. Suffering from energetic limitations, yields of C4-molecules produced by syngas fermentation are quite low compared with ABE fermentation using sugars as a substrate. On the other hand, fungal production of malic acid has high yields of product per gram metabolized substrate but is currently limited to sugar containing substrates. In this study, it was possible to show that Aspergilus oryzae is able to produce malic acid using acetate as sole carbon source which is a main product of acetogenic syngas fermentation. Bioreactor cultivations were conducted in 2.5 L stirred tank reactors. During the syngas fermentation part of the sequential mixed culture, Clostridium ljungdahlii was grown in modified Tanner medium and sparged with 20 mL/min of artificial syngas mimicking a composition of clean syngas from entrained bed gasification of straw (32.5 vol-% CO, 32.5 vol-% H2, 16 vol-% CO2, and 19 vol-% N2) using a microsparger. Syngas consumption was monitored via automated gas chromatographic measurement of the off-gas. For the fungal fermentation part gas sparging was switched to 0.6 L/min of air and a standard sparger. Ammonia content of medium for syngas fermentation was reduced to 0.33 g/L NH4Cl to meet the requirements for fungal production of dicarboxylic acids. Malic acid production performance of A. oryzae in organic acid production medium and syngas medium with acetate as sole carbon source was verified and gave YP∕S values of 0.28 g/g and 0.37 g/g respectively. Growth and acetate formation of C. ljungdahlii during syngas fermentation were not affected by the reduced ammonia content and 66 % of the consumed syngas was converted to acetate. The overall conversion

  15. Effect of modifications of dual acid-etched implant surfaces on periimplant bone formation. Part II: calcium phosphate coatings.

    PubMed

    Schliephake, H; Aref, A; Scharnweber, D; Rösler, S; Sewing, A

    2009-01-01

    The aim of the present study was to test the hypothesis that calcium phosphate coatings of dual acid-etched surfaces (DAEs) can improve periimplant bone regeneration. Ten adult female foxhounds received experimental titanium screw implants in the mandible 3 months after removal of all premolar teeth. Five types of surface states were evaluated in each animal: (i) implants with a machined surface (MS) (Control 1); (ii) implants with a DAE (Control 2); (iii) implants with a DAE coated with collagen I (Control 3); (iv) implants with a DAE with mineralized collagen I; and (v) implants with a DAE with a hydroxylapatite (HA) coating. Periimplant bone regeneration was assessed by histomorphometry after 1 and 3 months in five dogs each by measuring bone implant contact (BIC) and the volume density of the newly formed periimplant bone (BVD). After 1 month, mean BIC of experimental implants did not differ significantly from implants with DAE and collagen-coated surfaces, but was significantly higher than the MS implants. BVD was enhanced significantly only in implants with mineralized collagen coating compared with DAE and collagen-coated controls. After 3 months, the mean values of BIC had increased significantly in the group of implants with HA and mineralized collagen coating but were not significantly different from implants with DAE and collagen-coated surfaces. The same held true for the mean BVD values. In conclusion, the present study could not verify the hypothesis that calcium phosphate coatings of DAEs in the present form enhanced periimplant bone formation compared with the DAE surface alone. PMID:19126106

  16. Differences among Branded Hyaluronic Acids in Italy, Part 1: Data from In Vitro and Animal Studies and Instructions for Use

    PubMed Central

    Migliore, A.; Bizzi, E.; De Lucia, O.; Delle Sedie, A.; Bentivegna, M.; Mahmoud, Asmaa; Foti, C.

    2016-01-01

    BACKGROUND The use of hyaluronic acid (HA) for intra-articular (IA) injection is widespread around the world for patients affected by osteoarthritis. AIM The aim of this study is to identify scientific evidence from in vitro and in vivo studies supporting the use of IA HAs marketed in Italy. We also evaluated the accuracy of indications and contraindications reported in the leaflets of such HAs compared with the available scientific evidence. MATERIALS AND METHODS An extensive literature search was performed to identify all in vitro and in vivo model studies reporting on the effects of various HAs marketed in Italy for IA use. Data reported in the leaflets of different HA-based products for IA use were extracted and analyzed alongside evidence from in vitro and in vivo model studies. RESULTS Nine in vitro studies and 11 studies on animal models were examined. Comparing results with what is reported in the leaflets of HAs marketed in Italy, it was observed that many branded formulations are introduced in the market without any reporting of basic scientific evidence. Only 12.82% and 17.95% of branded products had been shown to be effective with scientific evidence from in vitro and in vivo studies, respectively. The rationale of use of these products is based on their nature, as if a class effect existed such that all HAs would yield similar effects. CONCLUSIONS Data on HAs deriving from in vitro and in vivo studies are scarce and relate to only a small percentage of products marketed in Italy. Many indications and contraindications are arbitrarily reported in Italian HA leaflets without the support of scientific evidence. Larger and brand-specific studies are necessary and should be reported in the leaflets to guide clinicians in making an appropriate choice regarding HA-based IA therapy. PMID:27257398

  17. Rational assembly of Pb(II)/Cd(II)/Mn(II) coordination polymers based on flexible V-shaped dicarboxylate ligand: Syntheses, helical structures and properties

    SciTech Connect

    Yang, Gao-Shan; Liu, Chong-Bo; Liu, Hong; Robbins, Julianne; Zhang, Z. John; Yin, Hong-Shan; Wen, Hui-Liang; Wang, Yu-Hua

    2015-05-15

    Six new coordination polymers, namely, [Pb(L)(H{sub 2}O)] (1), [Pb(L)(phen)] (2), [Pb{sub 2}(L){sub 2}(4,4′-bipy){sub 0.5}] (3), [Cd(L)(phen)] (4), [Cd(L)(4,4′-bipy)]·H{sub 2}O (5) and [Mn(L)(4,4′-bipy)]·H{sub 2}O (6) have been synthesized by the hydrothermal reaction of 2,2′-[hexafluoroisopropylidenebis(p-phenyleneoxy)]diacetic acid (H{sub 2}L) with Pb(II)/Cd(II)/Mn(II) in the presence of ancillary ligands 4,4′-bipyridine (4,4′-bipy) or 1,10-phenanthroline (phen). Complexes 1 and 4–6 exhibit 2-D structures, and complexes 2–3 display 3-D frameworks, of which L{sup 2−} ligands join metal ions to single-stranded helical chains of 1, 3–6 and double-stranded helical chains of 2. Complexes 2 and 3 also contain double-stranded Metal–O helices. Topology analysis reveals that complexes 1 and 4 both represent 4-connected sql net, 2 represents 6-connected pcu net, 3 exhibits a novel (3,12)-connected net, while 5 and 6 display (3,5)-connected gek1 net. The six complexes exhibit two kinds of inorganic–organic connectivities: I{sup 0}O{sup 2} for 1, 4–6, and I{sup 1}O{sup 2} for 2–3. The photoluminescent properties of 4–5 and the magnetic properties of 6 have been investigated. - Graphical abstract: Six new Pb(II)/Cd(II)/Mn(II) coordination polymers with helical structures based on flexible V-shaped dicarboxylate ligand have been synthesized and structurally characterized. Photoluminescent and magnetic properties have been investigated. - Highlights: • Six novel M(II) coordination polymers with 2,2′-[hexafluoroisopropylidenebis(p-phenyleneoxy)]diacetic acid and N-donor ligands. • Complexes 1–6 show diverse intriguing helical characters. • The luminescent properties of complexes 1–5 were investigated. • Complex 6 shows antiferromagnetic coupling.

  18. Spatio-temporal trends and monitoring design of perfluoroalkyl acids in the eggs of gull (Larid) species from across Canada and parts of the United States.

    PubMed

    Gewurtz, Sarah B; Martin, Pamela A; Letcher, Robert J; Burgess, Neil M; Champoux, Louise; Elliott, John E; Weseloh, D V Chip

    2016-09-15

    A large spatial dataset of perfluoroalkyl acid (PFAA) concentrations in eggs of herring gulls (Larus argentatus or congeneric species) collected from late April to early June between 2009 and 2014 from 28 colonies across Canada and parts of the Unites States was used to evaluate location-specific patterns in chemical concentrations and to generate hypotheses on the major sources affecting PFAA distributions. The highly bioaccumulative perfluorooctane sulfonic acid (PFOS) as well as other perfluoroalkyl sulfonic acids (PFSAs) showed the greatest concentrations in eggs from the lower Great Lakes of southern Ontario as well as from the St. Lawrence River. Despite the 2000 to 2002 phase-out of PFOS and related C8 chemistry by the major manufacturer at the time, ongoing losses from consumer products during use and disposal in urban/industrial locations continue to be major sources to the environment and are influencing the spatial trends of PFOS in Canada. In comparison to PFOS, perfluoroalkyl carboxylic acids (PFCAs) were not as concentrated in eggs in close proximity to urbanized/industrialized centers, but had surprisingly elevated levels in relatively remote regions such as Great Slave Lake, NT and East Bay in Hudson Bay, NU. The present results support the hypothesis that atmospheric transport and degradation of precursor chemicals, such as the fluorotelomer alcohols 8:2 FTOH and 10:2 FTOH, are influencing the spatial trends of PFCAs in Canada. A power analysis conducted on a representative urbanized/industrialized colony in the Toronto Harbour, ON, and a relatively remote colony in Lake Superior, emphasized the importance of consistent and long-term data collection in order to detect the anticipated changes in PFAA concentrations in Canadian gull eggs. PMID:27183458

  19. A novel two-dimensional layered framework built of strontium(II) with 4-nitrobenzene-1,3-dicarboxylic acid.

    PubMed

    Xiong, Li Qin; Qi, Chuan Min

    2007-06-01

    In poly[[aquastrontium(II)]-micro(6)-4-nitrobenzene-1,3-dicarboxylato-kappa(7)O(1):O(2):O(2):O(3):O(3),O(4):O(4)], [Sr(C(8)H(3)NO(6))(H(2)O)](n), the Sr(II) ion displays a distorted bicapped triangular prismatic configuration, defined by seven carboxyl O atoms from six symmetry-related ligands and one water molecule. The ligand molecules connect the Sr(II) ions into a two-dimensional layered framework in the ac plane, with close O...O contacts between the nitro groups and with each nitro group providing one acceptor O atom for a weak intermolecular C-H...O hydrogen bond. PMID:17551180

  20. Regional Air Quality Model Application of the Aqueous-Phase Photo Reduction of Atmospheric Oxidized Mercury by Dicarboxylic Acids

    EPA Science Inventory

    In most ecosystems, atmospheric deposition is the primary input of mercury. The total wet deposition of mercury in atmospheric chemistry models is sensitive to parameterization of the aqueous-phase reduction of divalent oxidized mercury (Hg2+). However, most atmospheric chemistry...

  1. Hydrothermal synthesis and structural characterization of Zn(II)- and Cd(II)-pyridine-2,3-dicarboxylate 2D coordination polymers, {(NH 4) 2[M(μ-pydc) 2]·2H 2O} n

    NASA Astrophysics Data System (ADS)

    Çolak, Alper Tolga; Pamuk, Gönül; Yeşilel, Okan Zafer; Yüksel, Fatma

    2011-12-01

    In this study, two novel coordination polymers {(NH 4) 2[M(μ-pydc) 2]·2H 2O} n (M = Zn(II), 1 and Cd(II), 2) (H 2pydc = Pyridine-2,3-dicarboxylic acid or quinolinic acid) have been hydrothermally synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. It has been observed that 1 and 2 have crystallized in the monoclinic space group P2 1/n. The M(II) ions are coordinated by the tridentate pydc bridging ligand through the oxygen atom of the carboxylate groups and the nitrogen atom of the pyridine ring in a bidentate manner and the oxygen atoms of carboxylate groups of other pydc ligands forming a distorted octahedral geometry. X-ray single crystal structural analyses put forth that two-dimensional frameworks were formed, and were assembled into a three-dimensional supramolecular structure by intermolecular N-H⋯O and O-H⋯O hydrogen bonding interactions.

  2. Foam for fracturing and acid stimulation. Part 2. Job control of a foam operation and a case history

    SciTech Connect

    Holcomb, D.L.

    1982-02-01

    This 3-part series of works is a comprehensive guide to the background, design and implementation of foamed stimulation for the treatment of oil and gas wells. It is adapted from the foam stimulation training manual developed and in use by Smith Energy Services. The manual is the product of 7 yr research and includes edited material already published, as well as information made available for the first time. This work should allow an interested party to acquire a basic understanding of the principles of foam and how it is utilized successfully as a stimulation medium. The following conclusions are made. Charts can be used onsite to maintain designed parameters during fracturing, if treating conditions are not as anticipated. Equations are used to determine wellhead treating pressures and changes in foam rate and quality. Increasing or decreasing the nitrogen rate maintains foam rate and quality. Increasing or decreasing the water rate maintains foam quality, but changes the frac rate correspondingly. Pumping rates can be changed and foam quality maintained, if there is a partial loss in nitrogen or water rate.

  3. Poly[aqua­bis(μ-benzene-1,2-dicarboxyl­ato)ethano­ltetra­lithium

    PubMed Central

    Rodríguez-Cuamatzi, Patricia; Tlahuext, Hugo; Höpfl, Herbert

    2009-01-01

    In the crystal structure of the title compound [Li4(C8H4O4)2(C2H5OH)(H2O)]n, there are four crystallographically independent metal centers each of which is coordinated by four O atoms. The benzene-1,2-dicarboxyl­ate 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 mol­ecules by the Li+ ions. Simultaneously, the water and ethanol mol­ecules are involved in O—H⋯O and C—H⋯π inter­actions. PMID:21582040

  4. Integrated engineering of β-oxidation reversal and ω-oxidation pathways for the synthesis of medium chain ω-functionalized carboxylic acids.

    PubMed

    Clomburg, James M; Blankschien, Matthew D; Vick, Jacob E; Chou, Alexander; Kim, Seohyoung; Gonzalez, Ramon

    2015-03-01

    An engineered reversal of the β-oxidation cycle was exploited to demonstrate its utility for the synthesis of medium chain (6-10-carbons) ω-hydroxyacids and dicarboxylic acids from glycerol as the only carbon source. A redesigned β-oxidation reversal facilitated the production of medium chain carboxylic acids, which were converted to ω-hydroxyacids and dicarboxylic acids by the action of an engineered ω-oxidation pathway. The selection of a key thiolase (bktB) and thioesterase (ydiI) in combination with previously established core β-oxidation reversal enzymes, as well as the development of chromosomal expression systems for the independent control of pathway enzymes, enabled the generation of C6-C10 carboxylic acids and provided a platform for vector based independent expression of ω-functionalization enzymes. Using this approach, the expression of the Pseudomonas putida alkane monooxygenase system, encoded by alkBGT, in combination with all β-oxidation reversal enzymes resulted in the production of 6-hydroxyhexanoic acid, 8-hydroxyoctanoic acid, and 10-hydroxydecanoic acid. Following identification and characterization of potential alcohol and aldehyde dehydrogenases, chnD and chnE from Acinetobacter sp. strain SE19 were expressed in conjunction with alkBGT to demonstrate the synthesis of the C6-C10 dicarboxylic acids, adipic acid, suberic acid, and sebacic acid. The potential of a β-oxidation cycle with ω-oxidation termination pathways was further demonstrated through the production of greater than 0.8 g/L C6-C10 ω-hydroxyacids or about 0.5 g/L dicarboxylic acids of the same chain lengths from glycerol (an unrelated carbon source) using minimal media.

  5. 2-methoxyethanol as a solvent for conductometric acid-base titrations.

    PubMed

    Schwartz, G A; Barker, B J

    1975-09-01

    Conductometric titrations of a series of organic acids in 2-methoxyethanol were performed with 1,3-diphenylguanidine (DPG) as titrant. For benzoic, p-chlorobenzoic and picric acids, phenylphenol and barbital, excellent recoveries were obtained from well-defined conductance vs. volume plots. Results for the dicarboxylic phthalic and adipic acids were also good. However, the titration curves for the difunctional salicylic and p-hydroxybenzoic acids were not clearly defined. The results are discussed and compared with cnductometric titrations of acids in other non-aqueous solvents. Several determinations of electrolyte conductance as a function of concentration revealed that, as expected, the selected substances are weak electrolytes in methoxyethanol.

  6. Syntheses, structures and magnetic properties of four coordination polymers based on nitrobenzene dicarboxylate and various N-donor coligands

    NASA Astrophysics Data System (ADS)

    Li, Gui-Lian; Yin, Wei-Dong; Liu, Guang-Zhen; Ma, Lu-Fang; Wang, Li-Ya

    2014-12-01

    Four new coordination polymers {[Ni(4-Nbdc)(bpa)(H2O)]}n (1), {[Co(4-Nbdc)(bpp) (H2O)]}n (2), {[Ni(4-Nbdc)(bpp)(H2O)]·H2O}n (3), and {[Mn2(3-Nbdc)2(bib)3]·2H2O}n (4) (4-Nbdc=4-nitrobenzene-1,2-dicarboxylate, 3-Nbdc=3-nitrobenzene-1,2-dicarboxylate, bpa=1,2-bi(4-pyridyl)ethane, bpp=1,3-bis(4-pyridyl)propane, and bib=1,4-bis(1-imidazoly)benzene), were synthesized by hydrothermal reactions, and characterized by single-crystal X-ray diffractions, elemental analysis, FT-IR, PXRD, TGA and magnetic analysis. Complexes 1 and 2 display quasi-trapezoidal chain and brick-wall layer, and both of them contain metal-carboxylate binuclear units. Complexes 3 and 4 exhibit three-dimensional frameworks with the (66) dia topology and (44.610.8)(44.62) fsc topology, and both of them contain metal-carboxylate chains. The carboxyl groups with syn-anti coordination mode mediate effectively the weak ferromagnetic coupling interaction within Ni(II)-carboxylate binuclear in 1 (J=1.27 cm-1) and Ni(II)-carboxylate chain in 3 (J=1.44 cm-1), respectively, and the carboxyl groups with anti-anti coordination mode leads to the classic antiferromagnetic coupling interaction within Mn(II)-carboxylate chain in 4 (J=-0.77 cm-1).

  7. SMA CARNI-VAL TRIAL PART II: A Prospective, Single-Armed Trial of L-Carnitine and Valproic Acid in Ambulatory Children with Spinal Muscular Atrophy

    PubMed Central

    Kissel, John T.; Scott, Charles B.; Reyna, Sandra P.; Crawford, Thomas O.; Simard, Louise R.; Krosschell, Kristin J.; Acsadi, Gyula; Elsheik, Bakri; Schroth, Mary K.; D'Anjou, Guy; LaSalle, Bernard; Prior, Thomas W.; Sorenson, Susan; Maczulski, Jo Anne; Bromberg, Mark B.; Chan, Gary M.; Swoboda, Kathryn J.

    2011-01-01

    Background Multiple lines of evidence have suggested that valproic acid (VPA) might benefit patients with spinal muscular atrophy (SMA). The SMA CARNIVAL TRIAL was a two part prospective trial to evaluate oral VPA and l-carnitine in SMA children. Part 1 targeted non-ambulatory children ages 2–8 in a 12 month cross over design. We report here Part 2, a twelve month prospective, open-label trial of VPA and L-carnitine in ambulatory SMA children. Methods This study involved 33 genetically proven type 3 SMA subjects ages 3–17 years. Subjects underwent two baseline assessments over 4–6 weeks and then were placed on VPA and L-carnitine for 12 months. Assessments were performed at baseline, 3, 6 and 12 months. Primary outcomes included safety, adverse events and the change at 6 and 12 months in motor function assessed using the Modified Hammersmith Functional Motor Scale Extend (MHFMS-Extend), timed motor tests and fine motor modules. Secondary outcomes included changes in ulnar compound muscle action potential amplitudes (CMAP), handheld dynamometry, pulmonary function, and Pediatric Quality of Life Inventory scores. Results Twenty-eight subjects completed the study. VPA and carnitine were generally well tolerated. Although adverse events occurred in 85% of subjects, they were usually mild and transient. Weight gain of 20% above body weight occurred in 17% of subjects. There was no significant change in any primary outcome at six or 12 months. Some pulmonary function measures showed improvement at one year as expected with normal growth. CMAP significantly improved suggesting a modest biologic effect not clinically meaningful. Conclusions This study, coupled with the CARNIVAL Part 1 study, indicate that VPA is not effective in improving strength or function in SMA children. The outcomes used in this study are feasible and reliable, and can be employed in future trials in SMA. Trial Regsitration Clinicaltrials.gov NCT00227266 PMID:21754985

  8. Benefits and risks of fish consumption Part II. RIBEPEIX, a computer program to optimize the balance between the intake of omega-3 fatty acids and chemical contaminants.

    PubMed

    Domingo, José L; Bocio, Ana; Martí-Cid, Roser; Llobet, Juan M

    2007-02-12

    In recent years, and based on the importance of fish as a part of a healthy diet, there has been a notable promotion of fish and seafood consumption. However, a number of recent studies have shown that fish may be a potential source of exposure to chemical pollutants, some of them with well known adverse effects on human health. Recently, we determined in 14 edible marine species the concentrations of eicosapentaenoic acid (EPA) and docosohexaenoic acid (DHA), as well as those of a number of chemical contaminants: Cd, Hg, Pb, polychlorinated dibenzo-p-dioxins and furans, polychlorinated biphenyls, hexachlorobenzene, polycyclic aromatic hydrocarbons, polychlorinated naphthalenes, polybrominated diphenylethers and polychlorinated diphenylethers. To quantitative establish the intake of these pollutants (risks) versus that of EPA+DHA (benefits), we designed a simple computer program, RIBEPEIX. The concentrations of EPA, DHA, and the chemical pollutants were introduced into the program. We here present how RIBEPEIX may be used as an easy tool to optimize fish consumption: most suitable species, frequency of consumption, and size of meals. RIBEPEIX can be useful not only for professionals (cardiologists, general physicians, nutritionists, toxicologists, etc.), but also for the general population. It is available at: .

  9. Design and synthesis of four coordination polymers generated from 2,2'-biquinoline-4,4'-dicarboxylate and aromatic bidentate ligands

    SciTech Connect

    Ye Junwei; Zhang Ping; Ye Kaiqi; Zhang Hongyu; Jiang Shimei; Ye Ling; Yang Guangdi; Wang Yue . E-mail: yuewang@jlu.edu.cn

    2006-02-15

    Four coordination polymers [Zn(bqdc)(phen)]{sub n} (1), [Zn(bqdc)(bpy)(H{sub 2}O)]{sub n} (2), [Mn(bqdc)(bpy)(H{sub 2}O){sub 2}]{sub n} (3) and [Mn(bqdc)(phen)(H{sub 2}O){sub 2}]{sub n} (4) (H{sub 2}bqdc=2,2'-biquinoline-4,4'-dicarboxylic acid, phen=1,10-phenanthroline and bpy=2,2'-bipyridyl) have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. Crystal data for 1: monoclinic system, C2/c, a=14.141(3)A, b=10.021(2)A, c=18.511(4)A, {beta}=103.78(3){sup o}, V=2547.6(9)A{sup 3}, Z=4. Crystal data for 2: monoclinic system, p2{sub 1}/n, a=13.656(3)A, b=10.015(2)A, c=19.127(4)A, {beta}=107.13(7){sup o}, V=2500.1(9)A{sup 3}, Z=4. Crystal data for 3: monoclinic system, C2/c, a=14.5050(8)A, b=15.1932(8)A, c=12.7549(6)A, {beta}=116.8010(11){sup o}, V=2508.9(2)A{sup 3}, Z=4. Crystal data for 4: monoclinic system, C2/c, a=14.1732(17)A, b=16.115(3)A, c=12.809(3)A, {beta}=117.04(3){sup o}, V=2605.7(8)A{sup 3}, Z=4. Single helix-like chains exist in 1. The supramolecular structure of 1 exhibits extended two-dimensional network while 2-4 display extended three-dimensional architectures based on interchain hydrogen bonding and {pi}-{pi} interactions. Compounds 1 and 2 show blue photoluminescence under UV light suggesting that they may be employed to develop luminescent materials. Compounds 3 and 4 show interesting magnetic behaviors.

  10. Oxidant and acid aerosol exposure in healthy subjects and subjects with asthma. Part I: Effects of oxidants, combined with sulfuric or nitric acid, on the pulmonary function of adolescents with asthma.

    PubMed

    Koenig, J Q; Covert, D S; Pierson, W E; Hanley, Q S; Rebolledo, V; Dumler, K; McKinney, S E

    1994-11-01

    Both peak flow decrements in children at summer camps and increased hospital admissions for asthma have been associated with summer "acid haze," which is composed of ozone and various acidic species. The objective of this study was to investigate the pulmonary effects of acid summer haze in a controlled laboratory setting. Twenty-eight adolescent subjects with allergic asthma, exercise-induced bronchospasm, and a positive response to a standardized methacholine challenge enrolled in the study; 22 completed the study. Each subject inhaled one of four test atmospheres by mouthpiece on two consecutive days. The order of exposure to the four test atmospheres was assigned via a random protocol: air, oxidants (0.12 parts per million [ppm]* ozone plus 0.30 ppm nitrogen dioxide), oxidants plus sulfuric acid at 70 micrograms/m3 of air, or oxidants plus 0.05 ppm nitric acid. Exposure to each of the different atmospheres was separated by at least one week. The exposures were carried out during alternating 15-minute periods of rest and moderate exercise for a total exposure period of 90 minutes per day. Pulmonary function was measured before and after exposure on both test days and again on the third day as a follow-up measurement. A postexposure methacholine challenge was performed on Day 3. Low methacholine concentrations were chosen for the postexposure challenge to avoid provoking a response. The protocol was designed to detect subtle changes in airway reactivity. The statistical significance of the pulmonary function values was tested using paired t tests. First, we compared the difference between baseline and postexposure measurements after air exposure on Day 1 with the differences between baseline and postexposure measurements after Day 1 exposure to each of the other three atmospheres. Second, we compared the difference between baseline and postexposure measurements after the Day 2 air exposure with the differences between baseline and postexposure measurements after

  11. Seasonal and spatial changes of free and bound organic acids in total suspended particles in Guangzhou, China

    NASA Astrophysics Data System (ADS)

    Ma, Shexia; Peng, Ping'an; Song, Jianzhong; Bi, Xinhui; Zhao, Jinping; He, Lulu; Sheng, Guoying; Fu, Jiamo

    2010-12-01

    The concentrations and compositions of free and bound organic acids in total suspended particles from typical urban, suburban and forest park sites of Guangzhou were determined in this study. The free form of organic acids (solvent extractable) in aerosols in Guangzhou varied with site and season. The suburban samples contained the highest contents of alkanoic, alkenoic and dicarboxylic acids. These findings were consistent with a higher supply of hydrocarbons and NOx in the suburban area. However, concentrations of aromatic acids were similar in the urban, suburban and forest park sites. Generally, winter season samples of the acids from anthropogenic sources contained more organic acids than summer season samples due to stronger removal by wet deposition in the summer. For the acids from botanic sources, the summer season samples were higher. In addition to the free acids, bound acids (solvent non-extractable) mainly formed by esterification of free acids were also found in the samples. In general, bound acids were higher than free acids. Esterification is mainly controlled by the pKa of organic acids and the atmospheric pH value. This explains why aromatic and dicarboxylic acids occur mainly as bound forms and why the samples from urban sites contained high levels of bound acids as the pH of rain water can reach 4.53. Concentrations of alkanoic and alkenoic acids in the aerosols of Guangzhou were much higher than those in the other areas studied.

  12. Acid rain

    SciTech Connect

    Not Available

    1985-01-01

    This report has four parts: they discuss acid rain in relation to acid soils, agriculture, forests, and aquatic ecosystems. Among findings: modern sources of acid deposition from the atmosphere for all the acid soils in the world, nor even chiefly responsible for those of northern U.S. Agriculture has its problems, but acid precipitation is probably not one of them. More research is needed to determine to what extent acid precipitation is responsible for forest declines and for smaller detrimental effects on forest growth where no damage to the foliage is evident. Many lakes and streams are extremely sensitive to added acids.

  13. Oxidative degradation of organic acids conjugated with sulfite oxidation in flue gas desulfurization

    SciTech Connect

    Lee, Y.I.

    1986-01-01

    Organic acid degradation conjugated with sulfite oxidation has been studied under flue gas desulfurization (EGD) conditions. The oxidative degradation constant, k/sub 12/, is defined as the ratio of organic acid degradation rate and sulfite oxidation rate after being normalized by the concentrations of organic acid and dissolved S(IV). K/sub 12/, not significantly affected by pH or dissolved oxygen, is around 10/sup -3/ in the absence of manganese or iron. However, k/sub 12/ is increased by certain transition metals such as Co, Ni, and Fe and is decreased by Mn and halides. Lower dissolved S(IV) magnified these effects. No k/sub 12/ greater than 4 x 10/sup -3/ or smaller than 0.1 x 10/sup -3/ has been observed. A free radical mechanism was proposed to describe the kinetics: (1) sulfate free radical is the major radical responsible to the degradation of organic acid; (2) ferrous generates sulfate radical by reacting with monoxypersulfate to enhance k/sub 12/; (3) manganous consumes sulfate radical to decrease k/sub 12/; (4) dissolved S(IV) competes with ferrous for monoxypersulfate and with manganous for sulfate radical to demonstrate the effects of dissolved S(IV) on k/sub 12/. Hydroxy and sulfonated carboxylic acids degrade approximately three times slower than saturated dicarboxylic acids; while maleic acid, an unsaturated dicarboxylic acid, degraded an order of magnitude faster. A wide spectrum of degradation products of adipic acid were found, including carbon dioxide - the major product, glutaric semialdehyde - the major retained product with low manganese, glutaric acid and valeric acids - the major retained product with high manganese, lower molecular weight mono- and dicarboxylic acids, other carbonyl compounds, and hydrocarbons.

  14. Functionalization of Microporous Lanthanide-Based Metal-Organic Frameworks by Dicarboxylate Ligands with Methyl-Substituted Thieno[2,3-b]thiophene Groups: Sensing Activities and Magnetic Properties.

    PubMed

    Wang, Suna; Cao, Tingting; Yan, Hui; Li, Yunwu; Lu, Jing; Ma, Ranran; Li, Dacheng; Dou, Jianmin; Bai, Junfeng

    2016-06-01

    From a methyl-substituted thieno[2,3-b]thiophene dicarboxylate, three types of three-dimensional (3-D) microporous lanthanide-based metal-organic frameworks, {[Ln(DMTDC)1.5(H2O)2]·DEF}n (type I, Ln = Eu 1, Tb 2), {[Ln(DMTDC)1.5(H2O)2]·0.5DMF·0.5H2O}n (type II, Ln = Gd 3, Dy 4, Er 5), and {[Ln4(DMTDC)6(DMF)2]·0.5DMF·1.5H2O}n (type III, Ln = Er 6) (H2DMTDC = 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid, DEF = N,N'-diethylformamide, DMF = N,N'-dimethylformamide), have been solventhermally synthesized. Types I and II are isostructural, which exhibit 1-D triangular channels constructed by double-stranded rod-shaped {Ln(CO2)2}n chains. Type III demonstrates an intriguing framework with triple-stranded rod-shaped {Ln(CO2)3}n chains arranged along the (1,1,0) and (1,-1,0) axes and possesses two kinds of triangular channels along two axes, respectively. Immobilization of the Lewis basic sites of thiophene groups induced gas adsorption and sensing properties into these microporous frameworks. Complexes 5(Er) and 6(Er) display moderate adsorption properties toward N2 and CO2, and the Qst of CO2 are as high as 36.3 and 34.8 kJ mol(-1), respectively. Complexes 1(Eu) and 2(Tb) exhibit sensing properties toward nitrobenzene, acetone, and the Cu(2+) ion in both DMF and aqueous solution. Complex 3(Gd) shows a significant magnetocaloric effect with ΔSm = 24.3 J·kg(-1)·K(-1) at 3.0 K and 7 T. Complex 4(Dy) exhibits slow magnetic relaxation with the energy barrier Δ/kB of 48.29 K. PMID:27168002

  15. A new Kagomé lattice coordination polymer based on bismuth and pyridine-2,5-dicarboxylate: structure and photoluminescent properties.

    PubMed

    Wibowo, Arief C; Smith, Mark D; zur Loye, Hans-Conrad

    2011-07-14

    A new Kagomé lattice topology assembled from ML(4) metal-organic polyhedra prepared using bismuth nitrate and pyridine-2,5-dicarboxylate has been obtained via a solvo-thermal reaction. Bi(pydc)(2)·(H(3)O(+))(H(2)O)(0.83) is, to the best of our knowledge, the first example of a bismuth-based coordination polymer to form with a Kagomé topology. Its structure and photoluminescence properties are reported.

  16. Lewis Acid Catalyzed Selective Reactions of Donor-Acceptor Cyclopropanes with 2-Naphthols.

    PubMed

    Kaicharla, Trinadh; Roy, Tony; Thangaraj, Manikandan; Gonnade, Rajesh G; Biju, Akkattu T

    2016-08-16

    Lewis acid-catalyzed reactions of 2-substituted cyclopropane 1,1-dicarboxylates with 2-naphthols is reported. The reaction exhibits tunable selectivity depending on the nature of Lewis acid employed and proceed as a dearomatization/rearomatization sequence. With Bi(OTf)3 as the Lewis acid, a highly selective dehydrative [3+2] cyclopentannulation takes place leading to the formation of naphthalene-fused cyclopentanes. Interestingly, engaging Sc(OTf)3 as the Lewis acid, a Friedel-Crafts-type addition of 2-naphthols to cyclopropanes takes place, thus affording functionalized 2-naphthols. Both reactions furnished the target products in high regioselectivity and moderate to high yields. PMID:27391792

  17. Preclinical toxicology and tissue platinum distribution of novel oral antitumour platinum complexes: ammine/amine platinum(IV) dicarboxylates.

    PubMed

    McKeage, M J; Morgan, S E; Boxall, F E; Murrer, B A; Hard, G C; Harrap, K R

    1994-01-01

    The preclinical toxicology and tissue platinum distribution of a series of six orally given antitumour platinum complexes [ammine/amine platinum(IV) dicarboxylates] with structural variations of their alicyclic amine (c-C5, c-C6 or c-C7), axial dicarboxylate (CH3, C3H7 or NHC2H5) or leaving substituents (Cl2 or OCOOCO) was studied in the mouse. Platinum tissue levels measured at 48 h after a single oral dose at 0.5 of the MTD were highest in the liver (6.0-19 micrograms/g) and second highest in the kidney (2.8-12 micrograms/g), and these levels were up to 5 times higher than those reported with equi-toxic doses of i.v. cisplatin and i.v. carboplatin. Platinum levels in the lung, heart, spleen, skin, skeletal muscle and brain were all < or = 3.1 micrograms/g at this dose level. Liver platinum levels measured at 2 h, 2 days, 6 days and 10 days after a single oral dose at the MTD ranged widely (from 15 to 109 micrograms platinum/g), were related to the number of carbon atoms in the axial dicarboxylate and alicyclic amine groups (r = 0.9389) and showed a diversity of time-course profiles. Elevations of plasma ALT activity were recorded with single oral doses of JM225 and JM256 at the MTD. Accumulation of platinum in the liver with repeated oral dosing weekly for 4 consecutive weeks at 0.5 of the MTD occurred with JM269 (3.3-fold increase, P < 0.05) and JM225 (2.4-fold increase, P < 0.05), and elevated plasma ALT activity (44 +/- 33 IU/l) was recorded with repeated oral doses of JM269. JM216 was selected from this series of analogues for further study on the basis of the elevated plasma ALT activity (JM225, JM256 and JM269), liver platinum accumulation (JM269 and JM225), poor activity against human ovarian carcinoma xenografts (JM291) or severe emetogenesis (JM221) of other examples. Following a single oral dose of JM216 at the MTD, transient reductions in the WBC (nadir, 1.6 x 10(9)/l, 2 days, 74% reduction), platelet count (nadir, 613 x 10(9)/l, 10 days, 33% reduction

  18. Leucine-induced activation of translational initiation is partly regulated by the branched-chain {alpha}-keto acid dehydrogenase complex in C2C12 cells

    SciTech Connect

    Nakai, Naoya . E-mail: nakai@hss.osaka-u.ac.jp; Shimomura, Yoshiharu; Tamura, Tomohiro; Tamura, Noriko; Hamada, Koichiro; Kawano, Fuminori; Ohira, Yoshinobu

    2006-05-19

    Branched-chain amino acid leucine has been shown to activate the translational regulators through the mammalian target of rapamycin. However, the leucine's effects are self-limiting because leucine promotes its own disposal by an oxidative pathway. The irreversible and rate-limiting step in the leucine oxidation pathway is catalyzed by the branched-chain {alpha}-keto acid dehydrogenase (BCKDH) complex. The complex contains E1 ({alpha}2{beta}2), E2, and E3 subunits, and its activity is abolished by phosphorylation of the E1{alpha} subunit by BCKDH kinase. The relationship between the activity of BCKDH complex and leucine-mediated activation of the protein translation was investigated using the technique of RNA interference. The activity of BCKDH complex in C2C12 cell was modulated by transfection of small interfering RNA (siRNA) for BCKDH E2 subunit or BCKDH kinase. Transfection of siRNAs decreased the mRNA expression and protein amount of corresponding gene. Suppression of either E2 subunit or kinase produced opposite effects on the cell proliferation and the activation of translational regulators by leucine. Suppression of BCKDH kinase for 48 h resulted in decreasing cell proliferation. In contrast, E2 suppression led to increased amount of total cellular protein. The phosphorylation of p70 S6 kinase by leucine was increased in E2-siRNA transfected C2C12 cells, whereas the leucine's effect was diminished in kinase-siRNA transfected cells. These results suggest that the activation of the translational regulators by leucine was partly regulated by the activity of BCKDH complex.

  19. Benefits and risks of fish consumption Part I. A quantitative analysis of the intake of omega-3 fatty acids and chemical contaminants.

    PubMed

    Domingo, José L; Bocio, Ana; Falcó, Gemma; Llobet, Juan M

    2007-02-12

    In recent years, and based on the importance of fish as a part of a healthy diet, there has been a notable promotion of fish consumption. However, the balance between health benefits and risks, due to the intake of chemical contaminants, is not well characterized. In the present study, edible samples of 14 marine species were analyzed for the concentrations of omega-3 fatty acids, as well as a number of metals and organic pollutants. Daily intakes were specifically determined for a standard adult of 70kg, and compared with the tolerable/admissible intakes of the pollutants, if available. Salmon, mackerel, and red mullet were the species showing the highest content of omega-3 fatty acids. The daily intakes of cadmium, lead, and mercury through fish consumption were 1.1, 2.0, and 9.9microg, respectively. Dioxins and furans plus dioxin-like polychlorinated biphenyls (PCBs) intake was 38.0pg WHO-TEQ/day, whereas those of polybrominated diphenyl ethers (PBDEs), polychlorinated diphenyl ethers (PCDEs), polychlorinated naphthalenes (PCNs) and hexachlorobenzene (HCB) were 20.8, 39.4, 1.53, and 1.50ng/day, respectively. In turn, the total intake of 16 analyzed polycyclic aromatic hydrocarbons (PAHs) was 268ng/day. The monthly fish consumption limits for human health endpoints based on the intake of these chemical contaminants were calculated for a 70 years exposure. In general terms, most marine species here analyzed should not mean adverse health effects for the consumers. However, the type of fish, the frequency of consumption, and the meal size are essential issues for the balance of the health benefits and risks of regular fish consumption.

  20. Syntheses, structures and magnetic properties of four coordination polymers based on nitrobenzene dicarboxylate and various N-donor coligands

    SciTech Connect

    Li, Gui-Lian; Yin, Wei-Dong; Liu, Guang-Zhen; Ma, Lu-Fang; Wang, Li-Ya

    2014-12-15

    Four new coordination polymers ([Ni(4-Nbdc)(bpa)(H{sub 2}O)]){sub n} (1), ([Co(4-Nbdc)(bpp) (H{sub 2}O)]){sub n} (2), ([Ni(4-Nbdc)(bpp)(H{sub 2}O)]·H{sub 2}O){sub n} (3), and ([Mn{sub 2}(3-Nbdc){sub 2}(bib){sub 3}]·2H{sub 2}O){sub n} (4) (4-Nbdc=4-nitrobenzene-1,2-dicarboxylate, 3-Nbdc=3-nitrobenzene-1,2-dicarboxylate, bpa=1,2-bi(4-pyridyl)ethane, bpp=1,3-bis(4-pyridyl)propane, and bib=1,4-bis(1-imidazoly)benzene), were synthesized by hydrothermal reactions, and characterized by single-crystal X-ray diffractions, elemental analysis, FT-IR, PXRD, TGA and magnetic analysis. Complexes 1 and 2 display quasi-trapezoidal chain and brick-wall layer, and both of them contain metal–carboxylate binuclear units. Complexes 3 and 4 exhibit three-dimensional frameworks with the (6{sup 6}) dia topology and (4{sup 4}.6{sup 10}.8)(4{sup 4}.6{sup 2}) fsc topology, and both of them contain metal–carboxylate chains. The carboxyl groups with syn-anti coordination mode mediate effectively the weak ferromagnetic coupling interaction within Ni(II)–carboxylate binuclear in 1 (J=1.27 cm{sup −1}) and Ni(II)–carboxylate chain in 3 (J=1.44 cm{sup −1}), respectively, and the carboxyl groups with anti-anti coordination mode leads to the classic antiferromagnetic coupling interaction within Mn(II)–carboxylate chain in 4 (J=−0.77 cm{sup −1}). - Highlights: • Four novel coordination polymers were hydrothermally synthesized. • 1 is 1D quasi-trapezoidal chain and 2 is brick-wall layer both with dinuclear units. • 3 and 4 show 3D frameworks both with 1D metal–carboxylate chains. • 1 and 3 exhibit ferromagnetic coupling, while 4 shows antiferromagnetic coupling.

  1. Poly[[dodeca­aqua­bis­(μ3-pyridine-2,6-dicarboxyl­ato)tetra­kis­(μ2-pyridine-2,6-dicarboxyl­ato)tri­calciumdieuropium(III)] 10.5-hydrate

    PubMed Central

    Shi, Fengjuan; Deng, Jiguang; Dai, Hongxing

    2012-01-01

    In the title compound, {[Ca3Eu2(C7H3NO4)6(H2O)12]·10.5H2O}n, the EuIII ion is nine-coordinated by three tridentate pyridine-2,6-dicarboxyl­ate (PDA) ligands, forming a [Eu(PDA)3]3− building block. The Ca2+ ions adopt two types of coordination geometries. One Ca2+ ion, lying on a twofold rotation axis, is eight-coordinated by four carboxyl­ate O atoms from four PDA ligands and four water mol­ecules, and the other two Ca2+ ions, each lying on an inversion center, are six-coordinated by two carboxyl­ate O atoms from two PDA ligands and four water mol­ecules. The carboxyl­ate groups bridge the EuIII and Ca2+ ions into a three-dimensional porous framework, with channels extending along [010] and [001] in which lattice water mol­ecules are located. Two of the lattice water mol­ecules are disordered over two sets of sites with equal occupancy and one water mol­ecule is 0.25-occupied. Numerous O—H⋯O hydrogen bonds involving the water mol­ecules and carboxyl­ate O atoms are present. PMID:22590167

  2. Interactions of amino acids, carboxylic acids, and mineral acids with different quinoline derivatives

    NASA Astrophysics Data System (ADS)

    Kalita, Dipjyoti; Deka, Himangshu; Samanta, Shyam Sundar; Guchait, Subrata; Baruah, Jubaraj B.

    2011-03-01

    A series of quinoline containing receptors having amide and ester bonds are synthesized and characterised. The relative binding abilities of these receptors with various amino acids, carboxylic acids and mineral acids are determined by monitoring the changes in fluorescence intensity. Among the receptors bis(2-(quinolin-8-yloxy)ethyl) isophthalate shows fluorescence enhancement on addition of amino acids whereas the other receptors shows fluorescence quenching on addition of amino acids. The receptor N-(quinolin-8-yl)-2-(quinolin-8-yloxy) propanamide has higher binding affinity for amino acids. However, the receptor N-(quinolin-8-yl)-2-(quinolin-8-yloxy)acetamide having similar structure do not bind to amino acids. This is attributed to the concave structure of the former which is favoured due to the presence of methyl substituent. The receptor bis(2-(quinolin-8-yloxy)ethyl) isophthalate do not bind to hydroxy carboxylic acids, but is a good receptor for dicarboxylic acids. The crystal structure of bromide and perchlorate salts of receptor 2-bromo-N-(quinolin-8-yl)-propanamide are determined. In both the cases the amide groups are not in the plane of quinoline ring. The structure of N-(quinolin-8-yl)-2-(quinolin-8-yloxy)acetamide, N-(2-methoxyphenethyl)-2-(quinolin-8-yloxy)acetamide and their salts with maleic acid as well as fumaric acid are determined. It is observed that the solid state structures are governed by the double bond geometry of these two acid. Maleic acid forms salt in both the cases, whereas fumaric acid forms either salt or co-crystals.

  3. Selection of background electrolyte for CZE analysis by a chemometric approach. Part I. Separation of a mixture of acidic non-steroidal anti-inflammatory drugs.

    PubMed

    Furlanetto, Sandra; Lanteri, Silvia; Orlandini, Serena; Gotti, Roberto; Giannini, Iacopo; Pinzauti, Sergio

    2007-03-12

    This paper is the first part of the presentation of a chemometric approach for the rapid selection of a suitable background electrolyte (BGE) in CZE analysis of small drug molecules. The strategy is based on principal component analysis and experimental design. In this first section, the approach is applied to the analysis of a mixture of six arylpropionic anti-inflammatory drugs. Initially, 222 possible aqueous background electrolytes (objects) were characterized using as descriptors pH, conductivity, ionic strength and relative viscosity. In order to allow the dissociation of the acidic analytes, this original data set was reduced to 154 background electrolytes with pH values higher than or equal to 5. Principal component analysis made it possible to graphically represent the new set of objects, described by the four variables, in a two-dimensional space. Among these electrolytes, Kennard-Stone algorithm selected ten objects to be tested by CZE, covering homogeneously principal component space. CZE analyses were carried out with the selected electrolytes, and 0.1 M borax was identified as the most suitable one for the specified application. Finally, the characteristics of the analysis were finely tuned by means of a response surface study, which allowed the best conditions to be determined: borax concentration, 0.09 M; methanol, 6% (v/v); temperature, 24 degrees C, voltage, 20 kV. Applying these conditions, a baseline resolution among the six compounds was obtained in less than 10 min.

  4. Two new pyridine-2,3-dicarboxylate coordination polymers prepared from zerovalent metal precursor: Syntheses, luminescent and magnetic properties

    NASA Astrophysics Data System (ADS)

    Semerci, Fatih; Yeşilel, Okan Zafer; Soylu, Mustafa Serkan; Yerli, Yusuf; Dal, Hakan

    2014-02-01

    Two new K+/Cu(II) and Zn(II) coordination polymers with pyridine-2,3-dicarboxylate (pydc), {K2[Cu(μ-pydc)2]·3H2O}n (1) and {[Zn(μ-pydc)(H2O)(4-mim)]·H2O}n (2) (4-mim=4-methylimidazole) have been synthesized from zerovalent metal and characterized by IR, EPR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. In the sandwiched 3D anionic framework of 1, pydc ligands exhibit hexadentate coordination; tridentate coordination bond with Cu(II) and tridentate ionic interaction with K+ ions. {K2[Cu(μ-pydc)2]·3H2O}n shows a rare topology consists of three dimensional (3,4,5)-connected network with the point symbol of {42.6}2{42.84}{43.6.86}2. The distorted square pyramidal geometry of 2 is completed with an nitrogen atom from 4-mim and aqua ligand to form a 1D polynuclear structure. The hydrogen bonds link the 1D chains into 3D architecture. The temperature dependent magnetic property of complex 1 has been studied. Complex 2 exhibits unusual yellow luminescence in the solid state at room temperature.

  5. Poly[[aqua­tris­(μ4-benzene-1,2-dicarboxyl­ato)dilanthanum(III)] hemihydrate

    PubMed Central

    Lush, Shie Fu; Shen, Fwu Ming

    2011-01-01

    The asymmetric unit of the title coordination polymer, {[La2(C8H4O4)3(H2O)]·0.5H2O}n, contains two independent LaIII atoms, one of which is surrounded by eight carboxyl­ate-O atoms from six benzene-1,2-dicarboxyl­ate (BDC) anions in a bicapped trigonal–prismatic geometry. The other LaIII atom is nine-coordinated in a tricapped trigonal–prismatic geometry, formed by eight carboxyl­ate-O atoms from six BDC anions and a coordinated water mol­ecule. The BDC anions bridge the LaIII atoms, forming a two-dimensional polymeric complex parallel to (001). The crystal structure contains weak O—H⋯O and non-classical C—H⋯O hydrogen bonds. A C—H⋯π inter­action is also present in the crystal structure. The uncoordinated water molecule shows half-occupation. PMID:22064614

  6. Synthesis, characterization and DFT studies of diethyl 4-hydroxy-6-nitro-4H-chromene-2,3-dicarboxylate

    NASA Astrophysics Data System (ADS)

    Dinparast, Leila; Valizadeh, Hassan; Vessally, Esmail; Bahadori, Mir Babak

    2016-02-01

    In the present study, diethyl 4-hydroxy-6-nitro-4H-chromene-2,3-dicarboxylate (DHNC) was synthesized and characterized using FT-IR, 1H and 13CNMR spectroscopy, mass spectrometry and UV-Vis (200-700 nm, in DMSO) spectrum. The structure of the title molecule was optimized at the B3LYP and PBE1PBE levels of theory using 6-311++G(d,p) basis set. The fundamental vibrational modes and chemical shifts of 1H and 13C of the present molecule were calculated using the B3LYP/6-311++G(d,p) and PBE1PBE/6-311++G(d,p) methods. UV-Vis spectrum of the title molecule was also calculated in DMSO and gas phase. The high stability and charge delocalization of DHNC arising from intramolecular hyperconjugative interaction confirmed with the NBO analysis at two DFT methods. Theoretical studies of the molecular orbitals such as HOMO-LUMO energy gap, mapped molecular electrostatic potential (MEP) surfaces and the Mulliken and NBO charges were also performed with the same levels of theory. In this work, the computed results and experimental observations support well each other.

  7. Loss-of-function mutations in the glutamate transporter SLC1A1 cause human dicarboxylic aminoaciduria

    PubMed Central

    Bailey, Charles G.; Ryan, Renae M.; Thoeng, Annora D.; Ng, Cynthia; King, Kara; Vanslambrouck, Jessica M.; Auray-Blais, Christiane; Vandenberg, Robert J.; Bröer, Stefan; Rasko, John E.J.

    2010-01-01

    Solute carrier family 1, member 1 (SLC1A1; also known as EAAT3 and EAAC1) is the major epithelial transporter of glutamate and aspartate in the kidneys and intestines of rodents. Within the brain, SLC1A1 serves as the predominant neuronal glutamate transporter and buffers the synaptic release of the excitatory neurotransmitter glutamate within the interneuronal synaptic cleft. Recent studies have also revealed that polymorphisms in SLC1A1 are associated with obsessive-compulsive disorder (OCD) in early-onset patient cohorts. Here we report that SLC1A1 mutations leading to substitution of arginine to tryptophan at position 445 (R445W) and deletion of isoleucine at position 395 (I395del) cause human dicarboxylic aminoaciduria, an autosomal recessive disorder of urinary glutamate and aspartate transport that can be associated with mental retardation. These mutations of conserved residues impeded or abrogated glutamate and cysteine transport by SLC1A1 and led to near-absent surface expression in a canine kidney cell line. These findings provide evidence that SLC1A1 is the major renal transporter of glutamate and aspartate in humans and implicate SLC1A1 in the pathogenesis of some neurological disorders. PMID:21123949

  8. One-step green synthesis of non-hazardous dicarboxyl cellulose flocculant and its flocculation activity evaluation.

    PubMed

    Zhu, Hangcheng; Zhang, Yong; Yang, Xiaogang; Liu, Hongyi; Shao, Lan; Zhang, Xiumei; Yao, Juming

    2015-10-15

    The waste management of used flocculants is a thorny issue in the field of wastewater treatment. To natural cellulose based flocculants, utilization of hazardous cellulose solvent and simplification of synthetic procedure are the two urgent problems needing to be further improved. In this work, a series of natural dicarboxyl cellulose flocculants (DCCs) were one-step synthesized via Schiff-base route. The cellulose solvent (NaOH/Urea solution) was utilized during the synthesis process. The full-biodegradable flocculants avoid causing secondary pollution to environment. The chemical structure and solution property of the DCC products were characterized by FT-IR, (1)H NMR, (13)C NMR, TGA, FESEM, charge density and ζ-potential. Kaolin suspension and effluent from paper mill were selected to evaluate the flocculation activity of the DCCs. Their flocculation performance was compared with that of commercial cationic polyacrylamide and poly aluminium chloride flocculants. The positive results showed that the NaOH/Urea solvent effectively promoted the dialdehyde cellulose (DAC) conversion to DCC in the one-step synthesis reaction. The DCCs with the carboxylate content more than 1 mmol/g exhibited steady flocculation performance to kaolin suspension in the broad pH range from 4 to 10. Its flocculation capacity to the effluent from paper mill also showed excellent.

  9. 2-Amino-5-methyl­pyridinium 1H-pyrazole-3,5-dicarboxyl­ate trihydrate

    PubMed Central

    Shahani, Tara; Fun, Hoong-Kun; Hemamalini, Madhukar

    2010-01-01

    In the title compound, 2C6H9N2 +·C5H2N2O4 2−·3H2O, the 1H-pyrazole-3,5-dicarboxyl­ate anion is close to planar [maximum deviation = 0.208 (1) Å]. The two distinct 2-amino-5-methyl­pyridinium cations are also almost planar, with maximum deviations of 0.018 (2) and 0.014 (2) Å. In the crystal, pairs of inter­molecular N—H⋯O and O—H⋯O hydrogen bonds connect neighbouring mol­ecules into dimers, generating R 2 2(8) and R 2 4(8) ring motifs, respectively. Further inter­molecular N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network. PMID:21589058

  10. Lignan dicarboxylates and terpenoids from the flower buds of Cananga odorata and their inhibitory effects on melanogenesis.

    PubMed

    Matsumoto, Takahiro; Nakamura, Seikou; Nakashima, Souichi; Fujimoto, Katsuyoshi; Yoshikawa, Masayuki; Ohta, Tomoe; Ogawa, Keiko; Matsuda, Hisashi

    2014-04-25

    The methanolic extract from the flower buds of Cananga odorata showed an inhibitory effect on melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells. From the methanolic extract, two new lignan dicarboxylates, canangalignans I and II, three new terpenoids, canangaterpenes I, II, and III, and eight known compounds were isolated. The structures of these compounds were elucidated on the basis of chemical/physicochemical evidence. Several mono- and sesquiterpene analogues significantly inhibited melanogenesis. In particular, canangaterpene I and (3R,3aR,8aS)-3-isopropyl-8a-methyl-8-oxo-1,2,3,3a,6,7,8,8a-octahydroazulene-5-carbaldehyde exhibited a potent inhibitory effect on melanogenesis [inhibition (%): 34.7±4.2 (p<0.01), 45.5±5.7 (p<0.01) at 1 μM, respectively] without inducing cytotoxicity. Moreover, the biological effect of these compounds was much stronger than that of the reference compound, arbutin. Thus, these isolated terpenoid derivatives may be promising therapeutic agents for the treatment of several skin disorders. PMID:24601675

  11. 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

  12. Caffeoylquinic acid derivatives isolated from the aerial parts of Gynura divaricata and their yeast α-glucosidase and PTP1B inhibitory activity.

    PubMed

    Chen, Jian; Mangelinckx, Sven; Ma, Li; Wang, Zhengtao; Li, Weilin; De Kimpe, Norbert

    2014-12-01

    The phytochemical investigation of natural products of Gynura divaricata led to the isolation of eleven caffeoylquinic acid derivatives. They were characterized by spectrometric methods as 5-O-caffeoylquinic acid (1), 5-O-p-coumaroylquinic acid (2), 5-O-feruloylquinic acid (3), methyl 5-O-caffeoylquinate (4), 3,4-dicaffeoylquinic acid (5), 3,5-dicaffeoylquinic acid (6), 4,5-dicaffeoylquinic acid (7), methyl 3,4-dicaffeoylquinate (8), methyl 3,5-dicaffeoylquinate (9), methyl 4,5-dicaffeoylquinate (10) and ethyl 4,5-dicaffeoylquinate (11). The individual compounds were screened for the inhibition of yeast α-glucosidase and Protein Tyrosine Phosphatase 1B (PTP1B) using in vitro assays. Among the isolated compounds, 3,4-dicaffeoylquinic acid (5), 4,5-dicaffeoylquinic acid (7), methyl 3,4-dicaffeoylquinate (8) and methyl 4,5-dicaffeoylquinate (10) exhibited significant inhibitory activities against α-glucosidase. In addition, 5-O-p-coumaroylquinic acid (2), 3,5-dicaffeoylquinic acid (6) and 4,5-dicaffeoylquinic acid (7) had considerable inhibitory effect against PTP1B. Based on these findings, the caffeoylquinic acid derivatives were deduced to be potentially responsible for the anti-diabetic activity of G. divaricata. The preliminary structure-activity relationship study suggests that the number and positioning of caffeoyl groups in the quinic acid derivatives are important for both α-glucosidase and PTP1B inhibitory potency. Moreover, the corresponding methyl esters of some dicaffeoylquinic acids have enhanced inhibitory activity against yeast α-glucosidase.

  13. Three novel indium MOFs derived from dicarboxylate ligands: Syntheses, structures and photoluminescent properties

    SciTech Connect

    Wang Liping; Song Tianyou; Li Chao; Xia Jing; Wang Shengyan; Wang Li; Xu Jianing

    2012-06-15

    The self-assembly of InCl{sub 3} with 1,4-phenylenediacetic acid (1,4-H{sub 2}pda), 1,3-benzendicarboxylic acid (1,3-H{sub 2}bdc) and 1,4-cyclohexanedicarboxylic acid (1,4- H{sub 2}chdc) generates three new In(III) MOFs, (Me{sub 2}NH{sub 2})[In(cis-1,4-pda){sub 2}] (1), HIn(1,3-bdc){sub 2}{center_dot}2DMF (2) and In(OH)(trans-1,4-chdc) (3) (Me{sub 2}NH=dimethylamine, DMF=N, N'-dimethylformamide). Compound 1 displays a novel 1D no-planar double chain. Although a mixture of cis- and trans-1,4-H{sub 2}pda was used, the product of compound 1 is a single phase with only cis-pda{sup 2-} ligands. Compound 2 possesses a 2D square lattice with sql topology. Interestingly, in compound 2, the 4-connected building unit containing InO{sub 6} octahedron is firstly occurred in In-MOFs. Compound 3 is built up from the infinite metal-oxide chains cross-linked by trans-1,4-chdc{sup 2-} to form 3D framework with rhombus-shaped channels. Furthermore, compounds 1-3 present intense solid-state fluorescent emissions at room temperature. - Graphical abstract: Three new In-MOFs based on different dicaboxylate acids display 1D chain, 2D layer and 3D open-framework, respectively and show strong luminescence emissions at room temperature. Highlights: Black-Right-Pointing-Pointer Three new indium metal-organic frameworks have been solvothermal synthesized. Black-Right-Pointing-Pointer The structural variation is attributed to the diverse coordination modes of ligands. Black-Right-Pointing-Pointer Compounds 1-3 exhibit 1D double chain, 2D layer and 3D open-framework, respectively. Black-Right-Pointing-Pointer These compounds exhibit strong solid-state luminescence emission at room temperature.

  14. Structure based identification of inhibitors for the SLC13 family of Na+/dicarboxylate cotransporters

    PubMed Central

    Colas, Claire; Pajor, Ana M.; Schlessinger, Avner

    2016-01-01

    In mammals, citric acid cycle intermediates play a key role in regulating various metabolic processes, such as fatty acid synthesis and glycolysis. Members of the sodium dependent SLC13 transporter family mediate the transport of di and tricarboxylates into cells. SLC13 members have been implicated in lifespan extension and resistance to high fat diets, thus, they are emerging drug targets for aging and metabolic disorders. We previously characterized key structural determinants of substrate and cation binding for the human NaDC3/SLC13A3 transporter using a homology model. Here, we combine computational modeling and virtual screening with functional and biochemical testing, to identify 9 previously unknown inhibitors for multiple members of the SLC13 family from human and mouse. Our results reveal previously unknown substrate selectivity determinants for the SLC13 family, including key residues that mediate ligand binding and transport, as well as promiscuous and specific SLC13 small molecule ligands. The newly discovered ligands can serve as chemical tools to further characterize the SLC13 family or as lead molecules for future development of potent inhibitors for the treatment of metabolic diseases and aging. Our results improve our understanding of the structural components that are important for substrate specificity in this physiologically important family as well as in other structurally related transport systems. PMID:26176240

  15. Relationship between adipic acid concentration and the core symptoms of autism spectrum disorders.

    PubMed

    Puig-Alcaraz, Carmen; Fuentes-Albero, Milagros; Cauli, Omar

    2016-08-30

    Dicarboxylic acids are an important source of information about metabolism and potential physiopathological alterations in children with autism spectrum disorders (ASDs). We measured the concentration between dicarboxylic adipic and suberic acids in children with an ASD and typically-developing (TD) children and analyzed any relationships between the severity of the core symptoms of ASDs and other clinical features (drugs, supplements, drugs, or diet). The core symptoms of autism were evaluated using the DSM-IV criteria, and adipic acid and suberic acid were measured in urine samples. Overall, no increase in the concentration of adipic acid in children with ASDs compared to TD children, however when considering vitamin B supplementation in ASD there were significantly increased level of urinary adipic acid in children with an ASD not taking vitamin B supplementation compared to supplemented children or to TD children. No significant difference were observed in suberic acid. Interestingly, the increase in adipic acid concentration was significantly and indirectly correlated with the severity of the deficit in socialization and communication skills in children with an ASD. Therefore, therapeutic treatments aimed at decreasing adipic acid concentration might not be beneficial for treating the core symptoms of ASDs.

  16. State estimation of an acid gas removal (AGR) plant as part of an integrated gasification combined cycle (IGCC) plant with CO2 capture

    SciTech Connect

    Paul, P.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    An accurate estimation of process state variables not only can increase the effectiveness and reliability of process measurement technology, but can also enhance plant efficiency, improve control system performance, and increase plant availability. Future integrated gasification combined cycle (IGCC) power plants with CO2 capture will have to satisfy stricter operational and environmental constraints. To operate the IGCC plant without violating stringent environmental emission standards requires accurate estimation of the relevant process state variables, outputs, and disturbances. Unfortunately, a number of these process variables cannot be measured at all, while some of them can be measured, but with low precision, low reliability, or low signal-to-noise ratio. As a result, accurate estimation of the process variables is of great importance to avoid the inherent difficulties associated with the inaccuracy of the data. Motivated by this, the current paper focuses on the state estimation of an acid gas removal (AGR) process as part of an IGCC plant with CO2 capture. This process has extensive heat and mass integration and therefore is very suitable for testing the efficiency of the designed estimators in the presence of complex interactions between process variables. The traditional Kalman filter (KF) (Kalman, 1960) algorithm has been used as a state estimator which resembles that of a predictor-corrector algorithm for solving numerical problems. In traditional KF implementation, good guesses for the process noise covariance matrix (Q) and the measurement noise covariance matrix (R) are required to obtain satisfactory filter performance. However, in the real world, these matrices are unknown and it is difficult to generate good guesses for them. In this paper, use of an adaptive KF will be presented that adapts Q and R at every time step of the algorithm. Results show that very accurate estimations of the desired process states, outputs or disturbances can be

  17. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part II. Recovery of Ammonia from Sour Waters

    SciTech Connect

    Poole, L.J.; King, C.J.

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO{sub 2} and H{sub 2}S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, SUCCiOlC acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The concentration

  18. Asymmetric synthesis of N-protected chiral 1-aminoalkylphosphonic acids and synthesis of side chain-functionalized depsiphosphonopeptides.

    PubMed

    Liu, Han; Cai, Shuzong; Xu, Jiaxi

    2006-05-01

    Optically active 1-aminoalkylphosphonic acid derivatives were synthesized in moderate yields and optical purities via Mannich-type reactions of benzyl carbamate, aldehydes, and optically pure chlorophosphites. Side chain-functionalized depsiphosphonopeptides were also prepared in satisfactory yields directly from one-pot reactions of benzyl carbamate, aldehydes, and diethyl (R,R)-2-chloro-1,3,2-dioxaphospholane-4,5-dicarboxylate. PMID:16285019

  19. Simultaneous determination of C2-C22 non-esterified fatty acids and other metabolically relevant carboxylic acids in biological material by gas chromatography of their benzyl esters.

    PubMed

    Schatowitz, B; Gercken, G

    1988-03-18

    A method for the simultaneous determination of non-esterified short-, medium- and long-chain fatty acids and other types of metabolically relevant carboxylic acids such as hydroxy, keto, aromatic and dicarboxylic acids in biological material by capillary gas chromatography of benzyl ester derivatives is described. Sample preparation avoiding incomplete isolation of carboxylic acids consisted of deproteinization and extraction with ethanol, fixation of carboxylic acids as carboxylates, removal of interfering compounds such as neutral lipids by hexane extraction and amino acids, acyl carnitines and other cations by cation-exchange chromatography, derivatization of keto groups of ketocarboxylic acids into O-methyl oximes and benzyl ester formation by reaction of the potassium carboxylates with benzyl bromide via crown ether catalysis. The sample preparation conditions were investigated, showing the usefulness of this method for quantitative determinations. Chromatograms obtained from human serum, human urine and rat heart ventricle and concentrations of carboxylic acids in these specimens are presented. PMID:3372640

  20. Two new pyridine-2,3-dicarboxylate coordination polymers prepared from zerovalent metal precursor: Syntheses, luminescent and magnetic properties

    SciTech Connect

    Semerci, Fatih; Yeşilel, Okan Zafer; Soylu, Mustafa Serkan; Yerli, Yusuf; Dal, Hakan

    2014-02-15

    Two new K{sup +}/Cu(II) and Zn(II) coordination polymers with pyridine-2,3-dicarboxylate (pydc), (K{sub 2}[Cu(μ-pydc){sub 2}]·3H{sub 2}O){sub n} (1) and ([Zn(µ-pydc)(H{sub 2}O)(4-mim)]·H{sub 2}O){sub n} (2) (4-mim=4-methylimidazole) have been synthesized from zerovalent metal and characterized by IR, EPR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. In the sandwiched 3D anionic framework of 1, pydc ligands exhibit hexadentate coordination; tridentate coordination bond with Cu(II) and tridentate ionic interaction with K{sup +} ions. (K{sub 2}[Cu(μ-pydc){sub 2}]·3H{sub 2}O){sub n} shows a rare topology consists of three dimensional (3,4,5)-connected network with the point symbol of (4{sup 2}.6){sub 2}(4{sup 2}.8{sup 4})(4{sup 3}.6.8{sup 6}){sub 2}. The distorted square pyramidal geometry of 2 is completed with an nitrogen atom from 4-mim and aqua ligand to form a 1D polynuclear structure. The hydrogen bonds link the 1D chains into 3D architecture. The temperature dependent magnetic property of complex 1 has been studied. Complex 2 exhibits unusual yellow luminescence in the solid state at room temperature. - Graphical abstract: Two new K{sup +}/Cu(II) and Zn(II) coordination polymers with pyridine-2,3-dicarboxylate (pydc), (K{sub 2}[Cu(μ-pydc){sub 2}]·3H{sub 2}O){sub n} (1) and ([Zn(µ-pydc)(H{sub 2}O)(4-mim)]·H{sub 2}O){sub n} (2) (4-mim=4-methylimidazole) have been synthesized from zerovalent metal and characterized by IR, EPR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. The water soluble (K{sub 2}[Cu(μ-pydc){sub 2}]·3H{sub 2}O){sub n} shows three dimensional a rare 3,4,5-connected network with the point symbol of (4{sup 2}.6){sub 2}(4{sup 2}.8{sup 4})(4{sup 3}.6.8{sup 6}){sub 2}. The temperature dependent magnetic property of complex 1 has been studied. Complex 2 exhibits unusual yellow luminescence in the solid state at room temperature. Display Omitted - Highlights: • Water

  1. Carbolic acid poisoning

    MedlinePlus

    Phenol poisoning; Phenylic acid poisoning; Hydroxybenzene poisoning; Phenic acid poisoning; Benzenol poisoning ... Below are symptoms of carbolic acid poisoning in different parts of the ... urine Decreased urine output No urine output EYES, EARS, ...

  2. Chiral Brønsted Acids for Asymmetric Organocatalysis

    NASA Astrophysics Data System (ADS)

    Kampen, Daniela; Reisinger, Corinna M.; List, Benjamin

    Chiral Brønsted acid catalysis is an emerging area of organocatalysis. Since the pioneering studies of the groups of Akiyama and Terada in 2004 on the use of chiral BINOL phosphates as powerful Brønsted acid catalysts in asymmetric Mannich-type reactions, numerous catalytic asymmetric transformations involving imine activation have been realized by means of this catalyst class, including among others Friedel-Crafts, Pictet-Spengler, Strecker, cycloaddition reactions, transfer hydrogenations, and reductive aminations. More recently, chiral BINOL phosphates found application in multicomponent and cascade reactions as for example in an asymmetric version of the Biginelli reaction. With the introduction of chiral BINOL-derived N-triflyl phosphoramides in 2006, asymmetric Brønsted acid catalysis is no longer restricted to reactive substrates. Also certain carbonyl compounds can be activated through these stronger Brønsted acid catalysts. In dealing with sensitive substrate classes, chiral dicarboxylic acids proved of particular value.

  3. [Clinical value of the sequential study of the uric acid in CSF in patients with cerebral diseases: Part I. Brain tumor and the effect of irradiation].

    PubMed

    Ueda, T; Wakisaka, S; Kinoshita, K; Adachi, H

    1984-03-01

    Uric acid is the end product of the purine metabolism in the human and is mainly excreted to the urine. The studies on cerebrospinal fluid (CSF) uric acid in patients with various neurological diseases were reported in the literature. In the present study the authors discussed the clinical value of the sequential study of the CSF uric acid content in patients with brain tumors. CSF was investigated for uric acid in 23 controls and 30 cases of brain tumor. The results were as follows: The mean value and standard deviation of the uric acid in CSF in controls was 0.23 +/- 0.13 mg/dl. The uric acid in CSF increased in patients with malignant brain tumor (0.49 +/- 0.22 mg/dl, p less than 0.005), but was in normal range in patients with benign brain tumor (0.32 +/- 0.13 mg/dl, 0.10 less than p less than 0.25). There was no significant correlation between CSF uric acid and CSF protein contents. Uric acid in the lumbar CSF was approximately 4 times higher than in the ventricular CSF in patients with brain tumor. The CSF uric acid had progressively increased during irradiation to the whole brain. The factors contributing to increase of the uric acid in CSF were thought to be increased permeability of blood-CSF barrier, global damage of brain tissue, increased nucleic acid catabolism in the central nervous system (CNS) for example in tumor, inflammation or immunoreaction, increased of xanthine, hypoxanthine or xanthine oxidase activity in the CNS, directly increased of plasma components into the CSF due to such as subarachnoid hemorrhage, intraventricular hemorrhage, bleeding in the tumor or surgical operation, dysfunction of the CSF dynamics.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Deduced products of C4-dicarboxylate transport regulatory genes of Rhizobium leguminosarum are homologous to nitrogen regulatory gene products.

    PubMed Central

    Ronson, C W; Astwood, P M; Nixon, B T; Ausubel, F M

    1987-01-01

    We have sequenced two genes dctB and dctD required for the activation of the C4-dicarboxylate transport structural gene dctA in free-living Rhizobium leguminosarum. The hydropathic profile of the dctB gene product (DctB) suggested that its N-terminal region may be located in the periplasm and its C-terminal region in the cytoplasm. The C-terminal region of DctB was strongly conserved with similar regions of the products of several regulatory genes that may act as environmental sensors, including ntrB, envZ, virA, phoR, cpxA, and phoM. The N-terminal domains of the products of several regulatory genes thought to be transcriptional activators, including ntrC, ompR, virG, phoB and sfrA. In addition, the central and C-terminal regions of DctD were strongly conserved with the products of ntrC and nifA, transcriptional activators that require the alternate sigma factor rpoN (ntrA) as co-activator. The central region of DctD also contained a potential ATP-binding domain. These results are consistent with recent results that show that rpoN product is required for dctA activation, and suggest that DctB plus DctD-mediated transcriptional activation of dctA may be mechanistically similar to NtrB plus NtrC-mediated activation of glnA in E. coli. PMID:3671068

  5. Genetic and epigenetic transgenerational implications related to omega-3 fatty acids. Part I: maternal FADS2 genotype and DNA methylation correlate with polyunsaturated fatty acid status in toddlers: an exploratory analysis.

    PubMed

    Lupu, Daniel S; Cheatham, Carol L; Corbin, Karen D; Niculescu, Mihai D

    2015-11-01

    Polyunsaturated fatty acid metabolism in toddlers is regulated by a complex network of interacting factors. The contribution of maternal genetic and epigenetic makeup to this milieu is not well understood. In a cohort of mothers and toddlers 16 months of age (n = 65 mother-child pairs), we investigated the association between maternal genetic and epigenetic fatty acid desaturase 2 (FADS2) profiles and toddlers' n-6 and n-3 fatty acid metabolism. FADS2 rs174575 variation and DNA methylation status were interrogated in mothers and toddlers, as well as food intake and plasma fatty acid concentrations in toddlers. A multivariate fit model indicated that maternal rs174575 genotype, combined with DNA methylation, can predict α-linolenic acid plasma concentration in all toddlers and arachidonic acid concentrations in boys. Arachidonic acid intake was predictive for its plasma concentration in girls, whereas intake of 3 major n-3 species (eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were predictive for their plasma concentrations in boys. FADS2 genotype and DNA methylation in toddlers were not related to plasma concentrations or food intakes, except for CpG8 methylation. Maternal FADS2 methylation was a predictor for the boys' α-linolenic acid intakes. This exploratory study suggests that maternal FADS2 genetic and epigenetic status could be related to toddlers' polyunsaturated fatty acid metabolism.

  6. Acid Precipitation

    ERIC Educational Resources Information Center

    Likens, Gene E.

    1976-01-01

    Discusses the fact that the acidity of rain and snow falling on parts of the U.S. and Europe has been rising. The reasons are still not entirely clear and the consequences have yet to be well evaluated. (MLH)

  7. MexAB-OprM specific efflux pump inhibitors in Pseudomonas aeruginosa. Part 4: Addressing the problem of poor stability due to photoisomerization of an acrylic acid moiety.

    PubMed

    Nakayama, Kiyoshi; Kuru, Noriko; Ohtsuka, Masami; Yokomizo, Yoshihiro; Sakamoto, Atsunobu; Kawato, Haruko; Yoshida, Ken-ichi; Ohta, Toshiharu; Hoshino, Kazuki; Akimoto, Katsuya; Itoh, Junko; Ishida, Hiroko; Cho, Aesop; Palme, Monica H; Zhang, Jason Z; Lee, Ving J; Watkins, William J

    2004-05-17

    Exchange of the ethylene tether in a series of pyridopyrimidine-based MexAB-OprM specific efflux pump inhibitors to an amide bond stabilized the olefin of the acrylic acid moiety, preventing facile photoisomerization to the Z-isomer. Furthermore, the activity was drastically improved in the amide tether variants, providing extremely potent acrylic acid and vinyl tetrazole analogues.

  8. The Determination of "Apparent" pKa's. Part II: An Experiment Using Very Weak Acids (pKa's > 11.4).

    ERIC Educational Resources Information Center

    Cawley, John J.

    1995-01-01

    Presents an experiment designed to show students that the Henderson-Hasselbalch equation will fail when they use this particular one-half titration technique for acids with large pKa's. Involves determining the apparent pKa for such acids and using that to calculate the true pKa. (JRH)

  9. Enantioselective excited-state quenching of racemic Tb (III) and Eu (III) Tris (pyridine-2,6-dicarboxylate) by vitamin B 12 derivatives

    NASA Astrophysics Data System (ADS)

    Meskers, Stefan C. J.; Dekkers, Harry P. J. M.

    1999-08-01

    Enantioselectivity in the dynamic quenching of the luminescence of the Δ and Λ enantiomers of racemic Tb(III)(pyridine-2,6-dicarboxylate=DPA) 33- and Eu(DPA) 33- by a series of corrinoids is demonstrated by time resolved luminescence and circular-polarization-of-luminescence (CPL) spectroscopy. Studied are cyanocobalamin (vitamin B 12), aquacobalamin (B 12a) and its conjugated base hydroxocobalamin (HOCbl), dicyanocobinamide ((CN) 2Cbi) and the heptamethyl ester of dicyanocobyrinic acid ((CN) 2Cby(OMe) 7). For this set of quenchers (Q), the diastereomeric quenching rate constants ( kqΔ and kqΛ) are reported together with the degree of enantioselectivity Eq=( kqΔ- kqΛ)/( kqΔ+ kqΛ). In the systems with Tb, values of the average rate constant kqavg(=( kqΔ+ kqΛ)/2) are 1.0, 2.9 and 0.53 10 8 M -1 s -1 for CNCbl, (CN) 2Cbi, (CN) 2Cby(OMe) 7 with Eq=-0.24, -0.20, +0.01 (standard error of Eq is 0.01). The quenching by B 12a is strongly dependent on pH and ionic strength ( I); when I=12 mM we find kqavg=5.3, Eq=-0.23 at pH 6.7 and kqavg=1.3, Eq=-0.27 at pH 8.9. Corresponding rates for Eu are 0.41, 27, 3.4 10 7 M -1 s -1 and for B 12a, 7.3 and 1.2 10 7 M -1 s -1, corresponding values for Eq -0.27, -0.29, +0.02, -0.21 and -0.29. The quenching reaction is modeled as a pre-equilibrium involving the formation of an encounter complex (association constant K) followed by the actual electronic energy transfer step (rate ket). By relating the quenching data with molecular structure it is argued that the binding in the encounter complex involves two hydrogen bonds between the uncoordinated carboxylate oxygen atom of two DPA ligands of Ln(DPA) 33- and two amide groups of the corrinoid, presumably involving the a and g, the a and b, or the b and g side chains. For some corrinoid/Ln(DPA) 33- complexes the association constants and enantioselectivities in the ground state are known (Spectrochimica Acta 55A (1999) 1837-1855), which allows for an estimate of the average rate of

  10. Acid-base titrations by stepwise addition of equal volumes of titrant with special reference to automatic titrations-III Presentation of a fully automatic titration apparatus and of results supporting the theories given in the preceding parts.

    PubMed

    Pehrsson, L; Ingman, F

    1977-02-01

    This paper forms Part III of a series in which the first two parts describe methods for evaluating titrations performed by stepwise addition of equal volumes of titrant. The great advantage of these methods is that they do not require an accurate calibration of the electrode system. This property makes the methods very suitable for routine work. e.g., in automatic analysis. An apparatus for performing such titrations automatically is presented. Further, results of titrations of monoprotic acids, a diprotic acid, an ampholyte, a mixture of an acid with its conjugate base, and mixtures of two acids with a small difference between the stability constants are given. Most of these titrations cannot be evaluated by the Gran or Hofstee methods but yield results having errors of the order of 0.1% if the methods proposed in Parts I and II of this series are employed. The advantages of the method of stepwise addition of equal volumes of titrant combined with the proposed evaluation methods, in comparison with common methods such as titration to a preset pH, are that all the data are used in the evaluation, permitting a statistical treatment and giving better possibilities for tracing systematic errors.

  11. Studies of the pulse charge of lead-acid batteries for PV applications. Part II. Impedance of the positive plate revisited

    NASA Astrophysics Data System (ADS)

    Kirchev, A.; Delaille, A.; Perrin, M.; Lemaire, E.; Mattera, F.

    In the second part of this publication series, dedicated to the pulse charge of the lead-acid battery, a special attention is paid to the impedance spectrum of the positive plate as a source for estimation of the electrostatic capacitance of the double layer (C dl) on the surface of the positive active mass. The impedance spectra were measured at open circuit for different states of charge (SoC) in H 2SO 4 with specific gravity 1.24 and 1.28 g ml -1. A substantial difference was observed in the impedance spectra of partially charged and partially discharged positive plates keeping the same value of the SOC. The impedance data were subjected to inductance error correction, followed by differential impedance analysis (DIA). Considering the results from DIA, the recently published equivalent circuits of the positive plate in charged and in discharged state and the gel-crystal model of the lead dioxide, we proposed a model of the positive plate in partial state of charge (PSoC). The analysis of the obtained experimental results using this model and DIA show that the double layer capacitance is not frequency distributed. The influence of the state of charge and state of health on the model parameters is discussed. One of the most interesting results is the dependence of C dl on SOC-it features a hysteresis at which the values of C dl during the charge are 5-6 times higher than the corresponding ones during the discharge. This result was discussed in terms of changes in the double layer structure considering the gel-crystal model of the lead dioxide. During the discharge in H 2SO 4 with specific gravity 1.28 g ml -1 a passivation process was detected as a high frequency pseudo-inductive loop in the Nyquist plots in PSoC. The passivation time constant is higher at 50-60% SOC and decreases to zero in the end of the discharge. During the charge in both electrolytes, pseudo-inductive time constant was observed too. It was attributed to the phenomena of the dehydration of Pb

  12. Screening procedure for detection of non-steroidal anti-inflammatory drugs and their metabolites in urine as part of a systematic toxicological analysis procedure for acidic drugs and poisons by gas chromatography-mass spectrometry after extractive methylation.

    PubMed

    Maurer, H H; Tauvel, F X; Kraemer, T

    2001-01-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used as analgesic and anti-rheumatic drugs, and they are often misused. A gas chromatographic-mass spectrometric (GC-MS) screening procedure was developed for their detection in urine as part of a systematic toxicological analysis procedure for acidic drugs and poisons after extractive methylation. The compounds were separated by capillary GC and identified by computerized MS in the full-scan mode. Using mass chromatography with the ions m/z 119, 135, 139, 152, 165, 229, 244, 266, 272, and 326, the possible presence of NSAIDs and their metabolites could be indicated. The identity of positive signals in such mass chromatograms was confirmed by comparison of the peaks underlying full mass spectra with the reference spectra recorded during this study. This method allowed the detection of therapeutic concentrations of acemetacin, acetaminophen (paracetamol), acetylsalicylic acid, diclofenac, diflunisal, etodolac, fenbufen, fenoprofen, flufenamic acid, flurbiprofen, ibuprofen, indometacin, kebuzone, ketoprofen, lonazolac, meclofenamic acid, mefenamic acid, mofebutazone, naproxen, niflumic acid, phenylbutazone, suxibuzone, tiaprofenic acid, tolfenamic acid, and tolmetin in urine samples. The overall recoveries of the different NSAIDs ranged between 50 and 80% with coefficients of variation of less than 15% (n = 5), and the limits of detection of the different NSAIDs were between 10 and 50 ng/mL (S/N = 3) in the full-scan mode. Extractive methylation has proved to be a versatile method for STA of various acidic drugs, poisons, and their metabolites in urine. It has also successfully been used for plasma analysis.

  13. 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.

  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.

    2004-06-01

    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.

  15. Propagated fixed-bed mixed-acid fermentation: Part I: Effect of volatile solid loading rate and agitation at high pH.

    PubMed

    Golub, Kristina W; Forrest, Andrea K; Mercy, Kevin L; Holtzapple, Mark T

    2011-11-01

    Countercurrent fermentation is a high performing process design for mixed-acid fermentation. However, there are high operating costs associated with moving solids, which is an integral component of this configuration. This study investigated the effect of volatile solid loading rate (VSLR) and agitation in propagated fixed-bed fermentation, a configuration which may be more commercially viable. To evaluate the role of agitation on fixed-bed configuration performance, continuous mixing was compared with periodic mixing. VSLR was also varied and not found to affect acid yields. However, increased VSLR and liquid retention time did result in higher conversions, productivity, acid concentrations, but lower selectivities. Agitation was demonstrated to be important for this fermentor configuration, the periodically-mixed fermentation had the lowest conversion and yields. Operating at a high pH (∼9) contributed to the high selectivity to acetic acid, which might be industrially desirable but at the cost of lower yield compared to a neutral pH.

  16. Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behavior.

    PubMed

    Patrick, Rhonda P; Ames, Bruce N

    2015-06-01

    Serotonin regulates a wide variety of brain functions and behaviors. Here, we synthesize previous findings that serotonin regulates executive function, sensory gating, and social behavior and that attention deficit hyperactivity disorder, bipolar disorder, schizophrenia, and impulsive behavior all share in common defects in these functions. It has remained unclear why supplementation with omega-3 fatty acids and vitamin D improve cognitive function and behavior in these brain disorders. Here, we propose mechanisms by which serotonin synthesis, release, and function in the brain are modulated by vitamin D and the 2 marine omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Brain serotonin is synthesized from tryptophan by tryptophan hydroxylase 2, which is transcriptionally activated by vitamin D hormone. Inadequate levels of vitamin D (∼70% of the population) and omega-3 fatty acids are common, suggesting that brain serotonin synthesis is not optimal. We propose mechanisms by which EPA increases serotonin release from presynaptic neurons by reducing E2 series prostaglandins and DHA influences serotonin receptor action by increasing cell membrane fluidity in postsynaptic neurons. We propose a model whereby insufficient levels of vitamin D, EPA, or DHA, in combination with genetic factors and at key periods during development, would lead to dysfunctional serotonin activation and function and may be one underlying mechanism that contributes to neuropsychiatric disorders and depression. This model suggests that optimizing vitamin D and marine omega-3 fatty acid intake may help prevent and modulate the severity of brain dysfunction.

  17. Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behavior.

    PubMed

    Patrick, Rhonda P; Ames, Bruce N

    2015-06-01

    Serotonin regulates a wide variety of brain functions and behaviors. Here, we synthesize previous findings that serotonin regulates executive function, sensory gating, and social behavior and that attention deficit hyperactivity disorder, bipolar disorder, schizophrenia, and impulsive behavior all share in common defects in these functions. It has remained unclear why supplementation with omega-3 fatty acids and vitamin D improve cognitive function and behavior in these brain disorders. Here, we propose mechanisms by which serotonin synthesis, release, and function in the brain are modulated by vitamin D and the 2 marine omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Brain serotonin is synthesized from tryptophan by tryptophan hydroxylase 2, which is transcriptionally activated by vitamin D hormone. Inadequate levels of vitamin D (∼70% of the population) and omega-3 fatty acids are common, suggesting that brain serotonin synthesis is not optimal. We propose mechanisms by which EPA increases serotonin release from presynaptic neurons by reducing E2 series prostaglandins and DHA influences serotonin receptor action by increasing cell membrane fluidity in postsynaptic neurons. We propose a model whereby insufficient levels of vitamin D, EPA, or DHA, in combination with genetic factors and at key periods during development, would lead to dysfunctional serotonin activation and function and may be one underlying mechanism that contributes to neuropsychiatric disorders and depression. This model suggests that optimizing vitamin D and marine omega-3 fatty acid intake may help prevent and modulate the severity of brain dysfunction. PMID:25713056

  18. Investigation of pyridine carboxylic acids in CM2 carbonaceous chondrites: Potential precursor molecules for ancient coenzymes

    NASA Astrophysics Data System (ADS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-07-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  19. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    NASA Technical Reports Server (NTRS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We lso report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  20. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    NASA Technical Reports Server (NTRS)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  1. 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.

  2. Lanthanide-thiophene-2,5-dicarboxylate frameworks: ionothermal synthesis, helical structures, photoluminescent properties, and single-crystal-to-single-crystal guest exchange.

    PubMed

    Zhan, Cai-Hong; Wang, Fei; Kang, Yao; Zhang, Jian

    2012-01-01

    Eight three-dimensional lanthanide-thiophene-2,5-dicarboxylate frameworks, [Ln(TDC)(2)]·(choline) (1-6; Ln = Gd, Nd, Eu, Er, Tb, Dy; TDC = thiophene-2,5-dicarboxylate), [Yb(TDC)(2)(e-urea)]·(choline)·H(2)O (7; e-urea = ethyleneurea), [Nd(2)(TDC)(3)(e-urea)(4)]·3(e-urea) (8) have been successfully prepared in deep eutectic solvents (choline chloride/e-urea), respectively. Compounds 1-7 are anionic frameworks with 8-connected bcu topology, while compound 8 features a neutral 6-connected rob-type framework with guest e-urea molecules. In these structures, lanthanide ions show dicapped trigonal prism, pentagonal bipyramid, and tricapped trigonal prism coordination configurations, respectively, and the TDC ligands exhibit different coordination modes. Versatile helical substructures are presented in these compounds. The photoluminescent properties of compounds 3 (Eu) and 8 (Nd) were studied. Moreover, compound 8 can perform single-crystal-to-single-crystal guest exchange. The ethanol-exchange mechanism of 8 can be ascribed to the kinetically controlled flexibility (KCF). PMID:22136232

  3. 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.

  4. Biotechnological production of muconic acid: current status and future prospects.

    PubMed

    Xie, Neng-Zhong; Liang, Hong; Huang, Ri-Bo; Xu, Ping

    2014-01-01

    Muconic acid (MA), a high value-added bio-product with reactive dicarboxylic groups and conjugated double bonds, has garnered increasing interest owing to its potential applications in the manufacture of new functional resins, bio-plastics, food additives, agrochemicals, and pharmaceuticals. At the very least, MA can be used to produce commercially important bulk chemicals such as adipic acid, terephthalic acid and trimellitic acid. Recently, great progress has been made in the development of biotechnological routes for MA production. This present review provides a comprehensive and systematic overview of recent advances and challenges in biotechnological production of MA. Various biological methods are summarized and compared, and their constraints and possible solutions are also described. Finally, the future prospects are discussed with respect to the current state, challenges, and trends in this field, and the guidelines to develop high-performance microbial cell factories are also proposed for the MA production by systems metabolic engineering. PMID:24751381

  5. Organic acids in continental background aerosols

    NASA Astrophysics Data System (ADS)

    Limbeck, Andreas; Puxbaum, Hans

    With a newly developed method aerosol samples from three distinctly different continental sites were analyzed: an urban site (Vienna), a savanna site in South Africa (Nylsvley Nature Reserve, NNR) and a free tropospheric continental background site (Sonnblick Observatory, SBO). In all samples a range of monocarboxylic acids (MCAs) and dicarboxylic acids (DCAs) has been identified and quantified. The three most abundant MCAs in Vienna were the C18, C16 and C14 acids with concentrations of 66, 45 and 36 ng m -3, respectively. At the mid tropospheric background site (SBO) the three most abundant MCAs were the C18, C16 and C12 acid. For the DCAs at all three sites oxalic, malonic and succinic acid were the dominant compounds. For some individual compounds an information about the sources could be obtained. For example the determined unsaturated MCAs in South Africa appear to result from biogenic sources whereas in Vienna those acids are considered to be derived from combustion processes. Oxalic and glyoxalic acid appear to have a free tropospheric air chemical source. The relative high amounts at SBO in comparison to Vienna can only be explained by secondary formation of oxalic acid in the atmosphere.

  6. Asymmetric epoxidation of allylic alcohols catalyzed by vanadium-binaphthylbishydroxamic Acid complex.

    PubMed

    Noji, Masahiro; Kobayashi, Toshihiro; Uechi, Yuria; Kikuchi, Asami; Kondo, Hisako; Sugiyama, Shigeo; Ishii, Keitaro

    2015-03-20

    A vanadium-binaphthylbishydroxamic acid (BBHA) complex-catalyzed asymmetric epoxidation of allylic alcohols is described. The optically active binaphthyl-based ligands BBHA 2a and 2b were synthesized from (S)-1,1'-binaphthyl-2,2'-dicarboxylic acid and N-substituted-O-trimethylsilyl (TMS)-protected hydroxylamines via a one-pot, three-step procedure. The epoxidations of 2,3,3-trisubstituted allylic alcohols using the vanadium complex of 2a were easily performed in toluene with a TBHP water solution to afford (2R)-epoxy alcohols in good to excellent enantioselectivities.

  7. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 2: aldol, Mannich addition reactions, deracemization and (S) to (R) interconversion of α-amino acids.

    PubMed

    Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim

    2013-11-01

    This review provides a comprehensive treatment of literature data dealing with asymmetric synthesis of α-amino-β-hydroxy and α,β-diamino acids via homologation of chiral Ni(II) complexes of glycine Schiff bases using aldol and Mannich-type reactions. These reactions proceed with synthetically useful chemical yields and thermodynamically controlled stereoselectivity and allow direct introduction of two stereogenic centers in a single operation with predictable stereochemical outcome. Furthermore, new application of Ni(II) complexes of α-amino acids Schiff bases for deracemization of racemic α-amino acids and (S) to (R) interconversion providing additional synthetic opportunities for preparation of enantiomerically pure α-amino acids, is also reviewed. Origin of observed diastereo-/enantioselectivity in the aldol, Mannich-type and deracemization reactions, generality and limitations of these methodologies are critically discussed.

  8. The effect of perinatal anoxia on amino acid metabolism in the developing brain. Part II: The effect of perinatal anoxia on the free amino acid patterns in CSF of infants and children.

    PubMed

    Kaneko, K

    1985-01-01

    To clarify the effects of perinatal anoxia on the subsequent amino acid metabolism in the brain of children, free amino acid levels in the cerebrospinal fluid (CSF) were determined in 15 children diagnosed as having cerebral palsy and/or mental retardation with perinatal anoxia, and 58 control children without anoxia, aged from 4 days to 12 yrs. There was no significant difference in total amino acid levels between anoxic children and the controls. In the controls, the Gln level in CSF was high, Arg, Asp and Glu levels in CSF were almost the same during infancy and childhood, and the levels of Orn, Lys, His, Tau, Thr, Ser, Asn, Gly, Ala, Val, Met, Ile, Leu, Tyr and Phe in CSF decreased with age until pre-school age. In the newborns and infants among the anoxic children, the levels of most free amino acids in CSF were relatively high compared with those of the controls and, except Glu and Gln, decreased with age during infancy. The Orn, His, Gly, Tyr and Phe levels in CSF of anoxic children were lower than those of the controls in older infants. These results suggest that perinatal anoxia affected free amino acid patterns in CSF of newborns and infants and that the subsequent disturbance of amino acid metabolism in their brains remained after birth.

  9. Characterization of Jamaican agro-industrial wastes. Part I: characterization of amino acids using HPLC: pre-column derivatization with phenylisothiocyanate.

    PubMed

    Bailey-Shaw, Y A; Golden, K D; Pearson, A G M; Porter, R B R

    2009-09-01

    Jamaican agro-industries generate large quantities of wastes, which are either discarded or under-utilized. In order to evaluate the possible utilization of these wastes, it is necessary that the profiles of the major biochemical groups be developed. This paper describes the determination of the amino acid composition of coffee, citrus, and rum distillery wastes using a reversed-phase high-performance liquid chromatography method. Acid hydrolysates of the wastes are derivatized with phenylisothiocyanate. They are analyzed as their phenylthiocarbamyl derivatives and determined quantitatively using norleucine as the internal standard. The presence of all the 17 amino acids investigated, nine of which include those essential for animal nutrition, are observed in the samples investigated, suggesting a high quality of protein with implications in the formulation of animal feeds. PMID:19772744

  10. Induced Smectic-G Phase through Intermolecular Hydrogen Bonding, Part XII: Thermal and Phase Behaviour of p-aminobenzonitrile: p-n-alkoxybenzoic acids

    NASA Astrophysics Data System (ADS)