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Sample records for adipic acid

  1. Adipic Acid: Vigorous Import Growth

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Adipic acid is mainly used to manufacture nylon 6,6, plasticizers, grease, polyurethane etc. There are three major commercial production processes: cyclohexane process, cyclohexanol process, butadiene carbonylation process, and the air oxidation of cyclohexane process constitute 93% of the total.

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

    Science.gov (United States)

    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

  3. CCN activation experiments with adipic acid: effect of particle phase and adipic acid coatings on soluble and insoluble particles

    Directory of Open Access Journals (Sweden)

    S. S. Hings

    2008-07-01

    Full Text Available Slightly soluble atmospherically relevant organic compounds may influence particle CCN activity and therefore cloud formation. Adipic acid is a frequently employed surrogate for such slightly soluble organic materials. The 11 published experimental studies on the CCN activity of adipic acid particles are not consistent with each other nor do they, in most cases, agree with the Köhler theory. The CCN activity of adipic acid aerosol particles was studied over a significantly wider range of conditions than in any previous single study. The work spans the conditions of the previous studies and also provides alternate methods for producing "wet" (deliquesced solution droplets and dry adipic acid particles without the need to produce them by atomization of aqueous solutions. The experiments suggest that the scatter in the previously published CCN measurements is most likely due to the difficulty of producing uncontaminated adipic acid particles by atomization of solutions and possibly also due to uncertainties in the calibration of the instruments. The CCN activation of the small (dm<150 nm initially dry particles is subject to a deliquescence barrier, while for the larger particles the activation follows the Köhler curve. Wet adipic acid particles follow the Köhler curve over the full range of particle diameters studied. In addition, the effect of adipic acid coatings on the CCN activity of both soluble and insoluble particles has also been studied. When a water-soluble core is coated by adipic acid, the CCN-hindering effect of particle phase is eliminated. An adipic acid coating on hydrophobic soot yields a CCN active particle. If the soot particle is relatively small (dcore≤102 nm, the CCN activity of the coated particles approaches the deliquescence line of adipic acid, suggesting that the total size of the particle determines CCN activation and the soot core acts as a scaffold.

  4. Evaporation of methyl- and dimethyl-substituted malonic, succinic, glutaric and adipic acid particles at ambient temperatures

    DEFF Research Database (Denmark)

    Mønster, Jacob Garbrecht; Rosenørn, Thomas; Svenningsson, Birgitta;

    2004-01-01

    Evaporation; organic aerosols; vapor pressure; dicarboxylic acid; maonic acid; succinic acid; glutaric acid; adipic acid......Evaporation; organic aerosols; vapor pressure; dicarboxylic acid; maonic acid; succinic acid; glutaric acid; adipic acid...

  5. 78 FR 20029 - Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance...

    Science.gov (United States)

    2013-04-03

    ... AGENCY 40 CFR Part 180 Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic...: This regulation establishes an exemption from the requirement of a tolerance for residues of castor oil... residues of castor oil, polymer with adipic acid, linoleic acid, oleic acid and ricinoleic acid on food...

  6. Effect of milling on DSC thermogram of excipient adipic acid.

    Science.gov (United States)

    Ng, Wai Kiong; Kwek, Jin Wang; Yuen, Aaron; Tan, Chin Lee; Tan, Reginald

    2010-03-01

    The purpose of this research was to investigate why and how mechanical milling results in an unexpected shift in differential scanning calorimetry (DSC) measured fusion enthalpy (Delta(fus)H) and melting point (T(m)) of adipic acid, a pharmaceutical excipient. Hyper differential scanning calorimetry (hyper-DSC) was used to characterize adipic acid before and after ball-milling. An experimental study was conducted to evaluate previous postulations such as electrostatic charging using the Faraday cage method, crystallinity loss using powder X-ray diffraction (PXRD), thermal annealing using DSC, impurities removal using thermal gravimetric analysis (TGA) and Karl Fischer titration. DSC thermograms showed that after milling, the values of Delta(fus)H and T(m) were increased by approximately 9% and 5 K, respectively. Previous suggestions of increased electrostatic attraction, change in particle size distribution, and thermal annealing during measurements did not explain the differences. Instead, theoretical analysis and experimental findings suggested that the residual solvent (water) plays a key role. Water entrapped as inclusions inside adipic acid during solution crystallization was partially evaporated by localized heating at the cleaved surfaces during milling. The correlation between the removal of water and melting properties measured was shown via drying and crystallization experiments. These findings show that milling can reduce residual solvent content and causes a shift in DSC results.

  7. 21 CFR 184.1009 - Adipic acid.

    Science.gov (United States)

    2010-04-01

    ... also known as 1,4-butanedicarboxylic acid or hexane-dioic acid. It is prepared by nitric acid oxidation... percent for fats and oil as defined in § 170.3(n)(12) of this chapter; 0.0004 percent for frozen...

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

    Science.gov (United States)

    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. PMID:27259135

  9. Catalytic routes towards acrylic acid, adipic acid and epsilon-caprolactam starting from biorenewables

    OpenAIRE

    Beerthuis, R.; Rothenberg, G.; Shiju, N.R.

    2015-01-01

    The majority of bulk chemicals are derived from crude oil, but the move to biorenewable resources is gaining both societal and commercial interest. Reviewing this transition, we first summarise the types of today's biomass sources and their economical relevance. Then, we assess the biobased productions of three important bulk chemicals: acrylic acid, adipic acid and epsilon-caprolactam. These are the key monomers for high-end polymers (polyacrylates, nylon 6.6 and nylon 6, respectively) and a...

  10. Poly(glycerol adipate)-fatty acid esters as versatile nanocarriers

    DEFF Research Database (Denmark)

    Weiss, Verena M; Naolou, Toufik; Hause, Gerd;

    2012-01-01

    Poly(glycerol adipate) (PGA) is a biodegradable polymer with promising features for nanoparticulate drug carrier systems. By acylation of PGA with fatty acids, composite systems with amphiphilic properties can be obtained. Variation of the fatty acid (laurate, stearate and behenate) and their sub......Poly(glycerol adipate) (PGA) is a biodegradable polymer with promising features for nanoparticulate drug carrier systems. By acylation of PGA with fatty acids, composite systems with amphiphilic properties can be obtained. Variation of the fatty acid (laurate, stearate and behenate...

  11. Poly(ether amide) segmented block copolymers with adipic acid based tetraamide segments

    NARCIS (Netherlands)

    Biemond, G.J.E.; Feijen, J.; Gaymans, R.J.

    2007-01-01

    Poly(tetramethylene oxide)-based poly(ether ester amide)s with monodisperse tetraamide segments were synthesized. The tetraamide segment was based on adipic acid, terephthalic acid, and hexamethylenediamine. The synthesis method of the copolymers and the influence of the tetraamide concentration, wh

  12. cis,cis-Muconic acid: separation and catalysis to bio-adipic acid for nylon-6,6 polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Vardon, Derek R.; Rorrer, Nicholas A.; Salvachúa, Davinia; Settle, Amy E.; Johnson, Christopher W.; Menart, Martin J.; Cleveland, Nicholas S.; Ciesielski, Peter N.; Steirer, K. Xerxes; Dorgan, John R.; Beckham, Gregg T.

    2016-01-01

    cis,cis-Muconic acid is a polyunsaturated dicarboxylic acid that can be produced renewably via the biological conversion of sugars and lignin-derived aromatic compounds. Subsequently, muconic acid can be catalytically converted to adipic acid -- the most commercially significant dicarboxylic acid manufactured from petroleum. Nylon-6,6 is the major industrial application for adipic acid, consuming 85% of market demand; however, high purity adipic acid (99.8%) is required for polymer synthesis. As such, process technologies are needed to effectively separate and catalytically transform biologically derived muconic acid to adipic acid in high purity over stable catalytic materials. To that end, this study: (1) demonstrates bioreactor production of muconate at 34.5 g L-1 in an engineered strain of Pseudomonas putida KT2440, (2) examines the staged recovery of muconic acid from culture media, (3) screens platinum group metals (e.g., Pd, Pt, Rh, Ru) for activity and leaching stability on activated carbon (AC) and silica supports, (4) evaluates the time-on-stream performance of Rh/AC in a trickle bed reactor, and (5) demonstrates the polymerization of bio-adipic acid to nylon-6,6. Separation experiments confirmed AC effectively removed broth color compounds, but subsequent pH/temperature shift crystallization resulted in significant levels of Na, P, K, S and N in the crystallized product. Ethanol dissolution of muconic acid precipitated bulk salts, achieving a purity of 99.8%. Batch catalysis screening reactions determined that Rh and Pd were both highly active compared to Pt and Ru, but Pd leached significantly (1-9%) from both AC and silica supports. Testing of Rh/AC in a continuous trickle bed reactor for 100 h confirmed stable performance after 24 h, although organic adsorption resulted in reduced steady-state activity. Lastly, polymerization of bio-adipic acid with hexamethyldiamine produced nylon-6,6 with comparable properties to its petrochemical counterpart

  13. Synthesis and characterization of aliphatic polyesters from glycerol, by-product of biodiesel production, and adipic acid

    Directory of Open Access Journals (Sweden)

    Michel de Meireles Brioude

    2007-12-01

    Full Text Available In the present work, polyesters were prepared from the polycondensation between glycerol and adipic acid using dibutyltin dilaurate as catalyst. Three glycerol: adipic acid molar ratio were used for the bulk polymerization namely: 2:2; 2:3 and 2:4. FTIR confirmed the esterification of glycerol by the acid for all the polymers. DSC and XRD indicated no crystallinity for all the polymers. The morphology of the materials are characterized by globular structure, which may suggest compositional fluctuations throughout the samples.

  14. Engineering a Polyketide Synthase for In Vitro Production of Adipic Acid.

    Science.gov (United States)

    Hagen, Andrew; Poust, Sean; Rond, Tristan de; Fortman, Jeffrey L; Katz, Leonard; Petzold, Christopher J; Keasling, Jay D

    2016-01-15

    Polyketides have enormous structural diversity, yet polyketide synthases (PKSs) have thus far been engineered to produce only drug candidates or derivatives thereof. Thousands of other molecules, including commodity and specialty chemicals, could be synthesized using PKSs if composing hybrid PKSs from well-characterized parts derived from natural PKSs was more efficient. Here, using modern mass spectrometry techniques as an essential part of the design-build-test cycle, we engineered a chimeric PKS to enable production one of the most widely used commodity chemicals, adipic acid. To accomplish this, we introduced heterologous reductive domains from various PKS clusters into the borrelidin PKS' first extension module, which we previously showed produces a 3-hydroxy-adipoyl intermediate when coincubated with the loading module and a succinyl-CoA starter unit. Acyl-ACP intermediate analysis revealed an unexpected bottleneck at the dehydration step, which was overcome by introduction of a carboxyacyl-processing dehydratase domain. Appending a thioesterase to the hybrid PKS enabled the production of free adipic acid. Using acyl-intermediate based techniques to "debug" PKSs as described here, it should one day be possible to engineer chimeric PKSs to produce a variety of existing commodity and specialty chemicals, as well as thousands of chemicals that are difficult to produce from petroleum feedstocks using traditional synthetic chemistry.

  15. Engineering a Polyketide Synthase for In Vitro Production of Adipic Acid.

    Science.gov (United States)

    Hagen, Andrew; Poust, Sean; Rond, Tristan de; Fortman, Jeffrey L; Katz, Leonard; Petzold, Christopher J; Keasling, Jay D

    2016-01-15

    Polyketides have enormous structural diversity, yet polyketide synthases (PKSs) have thus far been engineered to produce only drug candidates or derivatives thereof. Thousands of other molecules, including commodity and specialty chemicals, could be synthesized using PKSs if composing hybrid PKSs from well-characterized parts derived from natural PKSs was more efficient. Here, using modern mass spectrometry techniques as an essential part of the design-build-test cycle, we engineered a chimeric PKS to enable production one of the most widely used commodity chemicals, adipic acid. To accomplish this, we introduced heterologous reductive domains from various PKS clusters into the borrelidin PKS' first extension module, which we previously showed produces a 3-hydroxy-adipoyl intermediate when coincubated with the loading module and a succinyl-CoA starter unit. Acyl-ACP intermediate analysis revealed an unexpected bottleneck at the dehydration step, which was overcome by introduction of a carboxyacyl-processing dehydratase domain. Appending a thioesterase to the hybrid PKS enabled the production of free adipic acid. Using acyl-intermediate based techniques to "debug" PKSs as described here, it should one day be possible to engineer chimeric PKSs to produce a variety of existing commodity and specialty chemicals, as well as thousands of chemicals that are difficult to produce from petroleum feedstocks using traditional synthetic chemistry. PMID:26501439

  16. Novel microbial screen for detection of 1,4-butanediol, ethylene glycol, and adipic acid.

    Science.gov (United States)

    Stieglitz, B; Weimer, P J

    1985-03-01

    A novel microbial-screening procedure was developed for separate detection of 1,4-butanediol, ethylene glycol, and adipic acid, three commercially important oxychemicals potentially derivable from bacterial omega-oxidation of n-butanol, ethanol, and hexanoic acid, respectively. The screening method involved postproduction addition of one of several specific Pseudomonas strains which produce a soluble fluorescent pigment during growth on the product of interest. A mutation and selection procedure was developed for isolation of specific strains with phenotypes for growth and pigment production on the desired product (e.g., 1,4-butanediol), but not on its bioconversion substrate (e.g., n-butanol), common by-products (e.g., n-butyrate), or product isomers. Pigment production was growth associated and required cultivation of the screening strains under limiting Fe3+ concentrations. The pigments resembled well-characterized, iron-chelating siderophores produced by other fluorescent pseudomonads. The sensitivity of the assay for product accumulation was enhanced by (i) conducting the screening in microtiter dishes to permit examination of individual isolates of putative producers and to control product diffusion, (ii) using a wavelength cutoff filter to reduce background source light, and (iii) using adapted screening strains which grew at lower (0.3 mM) concentrations of test compounds. The potential utility of the method for detecting a variety of oxidative catabolic products is discussed.

  17. Properties of alkali-solubilized collagen solution crosslinked by N-hydroxysuccinimide activated adipic acid

    Science.gov (United States)

    Chen, Yihui; Zhang, Min; Liu, Wentao; Li, Guoying

    2011-03-01

    The effect of N-hydroxysuccinimide activated adipic acid (NHS-AA) on the properties of alkali-solubilized collagen solutions was examined. The residual amino group content in crosslinked collagen, determined by trinitrobenzensulfonic acid (TNBS) assay, was decreased with increasing NHS-AA concentration. The results from differential scanning calorimeter (DSC) indicated that the maximum denaturation temperature ( T d) of crosslinked collagen solution was about 4.2°C higher than that of un-crosslinked collagen solution (36.6°C). Moreover, the values of storage modulus ( G'), loss modulus ( G″) and complex viscosity ( η*), obtained by means of dynamic frequency sweeps, were increased as NHS-AA concentration added up to 1.5 mM, and then decreased slightly when further increased NHS-AA concentration. Besides, for collagen solution crosslinked with 1.5 mM NHS-AA, dynamic denaturation temperature ( T dd) was about 1.1°C lower than T d (40.8°C), and the Arrhenius-type time-temperature superposition (TTS) principle was applied to yield the activation energy to be 474.4 kJmol-1.

  18. Synthesis and in vitro bio degradation of poly(ethylene adipate- co-D,L-lactic acid copolymers (PLEA

    Directory of Open Access Journals (Sweden)

    Bakouri Hichem

    2014-09-01

    Full Text Available The present research mainly focused on the synthesis and study of bio degradation of poly (ethylene adipate-co-D,L-lactic acid. PLEA were prepared via ring opening polymerization from D,L-lactide and poly(ethylene adipate. PLEA was characterized by 1H NMR spectra and DSC; results showed that those properties showed high dependence on its composition.In vitro degradation behaviors of PLEA have been systematically investigated up to 12 weeks in phosphate buffer saline solution at 37 °C. The weight and polymer molecular weight were measured as a function of degradation time. Bacterial degradation was completed by investigating the physico-chemical properties using spectroscopy FTIR and DSC.

  19. A green two-step process for adipic acid production from cyclohexene. A study on parameters affecting selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Cavani, F.; Macchia, F.; Pino, R.; Raabova, K.; Rozhko, E. [Bologna Univ. (Italy). Dipt. di Chimica Industriale e dei Materiali; Alini, S.; Accorinti, P.; Babini, G. [Radici Chimica SpA, Novara (Italy)

    2011-07-01

    In this paper, we report about the effect of reaction parameters on catalytic behavior in a twostep process aimed at the synthesis of adipic acid from cyclohexene. In the first step, cyclohexene reacts with an aqueous solution of hydrogen peroxide, under conditions leading to the formation of trans-1,2-cyclohexandiol as the prevailing product; the reaction is catalysed by tungstic acid, in the presence of phosphoric acid and of a PT agent. In the second step, 1,2-cyclohexandiol is oxidized with air, in the presence of an heterogeneous catalyst made of alumina-supported Ru(OH){sub 3}. This process is aimed at using the minimal amount of the costly hydrogen peroxide, since only one mole is theoretically needed per mole of cyclohexene. The first step afforded very high yield to the glycol, using only a slight excess of hydrogen peroxide. However, the second step turned out to be the more critical one, since the selectivity to adipic acid was very low because of the concomitant occurrence of several undesired side reactions. The latter were in part due to the reaction conditions used, which were necessary for the activation of cyclohexandiol. (orig.)

  20. Electrospun Scaffolds from Low Molecular Weight Poly(ester amide)s Based on Glycolic Acid, Adipic Acid and Odd or Even Diamines

    OpenAIRE

    Sara Keiko Murase; Luís Javier del Valle; Jordi Puiggalí

    2015-01-01

    Electrospinning of regular poly(ester amide)s (PEAs) constituted by glycolic acid, adipic acid and diamines with five and six carbon atoms has been carried out. Selected PEAs were constituted by natural origin products and could be easily prepared by a polycondensation method that avoids tedious protection and deprotection steps usually required for obtaining polymers with a regular sequence. Nevertheless, the synthesis had some limitations that mainly concerned the final low/moderate molecul...

  1. Metabolism of phytanic acid and 3-methyl-adipic acid excretion in patients with adult Refsum disease.

    Science.gov (United States)

    Wierzbicki, Anthony S; Mayne, Phillip D; Lloyd, Matthew D; Burston, David; Mei, Guam; Sidey, Margaret C; Feher, Michael D; Gibberd, F Brian

    2003-08-01

    Adult Refsum disease (ARD) is associated with defective alpha-oxidation of phytanic acid (PA). omega-Oxidation of PA to 3-methyl-adipic acid (3-MAA) occurs although its clinical significance is unclear. In a 40 day study of a new ARD patient, where the plasma half-life of PA was 22.4 days, omega-oxidation accounted for 30% initially and later all PA excretion. Plasma and adipose tissue PA and 3-MAA excretion were measured in a cross-sectional study of 11 patients. The capacity of the omega-oxidation pathway was 6.9 (2.8-19.4) mg [20.4 (8.3-57.4) micromol] PA/day. 3-MAA excretion correlated with plasma PA levels (r = 0.61; P = 0.03) but not adipose tissue PA content. omega-Oxidation during a 56 h fast was studied in five patients. 3-MAA excretion increased by 208 +/- 58% in parallel with the 158 (125-603)% rise in plasma PA. Plasma PA doubled every 29 h, while 3-MAA excretion followed second-order kinetics. Acute sequelae of ARD were noted in three patients (60%) after fasting. The omega-oxidation pathway can metabolise PA ingested by patients with ARD, but this activity is dependent on plasma PA concentration. omega-Oxidation forms a functional reserve capacity that enables patients with ARD undergoing acute stress to cope with limited increases in plasma PA levels.

  2. Clean synthesis of adipic acid from cyclohexene in microemulsions with stearyl dimethyl benzyl ammonium chloride as surfactant: From the laboratory to bench scale

    OpenAIRE

    Quesada-Peñate, Isariebel; Lesage, Geoffroy; Cognet, Patrick; Poux, Martine

    2012-01-01

    International audience Adipic acid, HOOC(CH2)4COOH, is a white crystalline solid used primarily in the manufacture of nylon-6,6 polyamide. In industry, adipic acid is mainly produced by oxidation of cyclohexane with air and nitric acidfollowing a homogeneous two-step route. However, this process leads to the formation of nitrous oxide, a greenhouse gas that has to be decomposed. The aim of this study was the development of a clean technology at pilot scale in order to obtain and recover pu...

  3. Measurement and Correlation of Solubilities of Adipic Acid in Different Solvents%已二酸溶解度的测定与关联

    Institute of Scientific and Technical Information of China (English)

    毛治博; 孙晓波; 栾向海; 王钰; 刘国际

    2009-01-01

    Using a simple and reliable apparatus, the solubilities of adipic acid in water, ethanol, chloroform, n-butanol and acetone are determined by the analytic method. The results are correlated with Xh equation, Apelblat equation, and UNIFAC equation. The solubilities calculated by these models are in good agreement with experi-mental data, so that the models can meet the requirements of engineering design.

  4. Dissociative Ionization Mechanism and Appearance Energies in Adipic Acid Revealed by Imaging Photoelectron Photoion Coincidence, Selective Deuteration, and Calculations.

    Science.gov (United States)

    Heringa, Maarten F; Slowik, Jay G; Prévôt, André S H; Baltensperger, Urs; Hemberger, Patrick; Bodi, Andras

    2016-05-26

    Adipic acid, a model compound for oxygenated organic aerosol, has been studied at the VUV beamline of the Swiss Light Source. Internal energy selected cations were prepared by threshold photoionization using vacuum ultraviolet synchrotron radiation and imaging photoelectron photoion coincidence spectroscopy (iPEPICO). The threshold photoelectron spectrum yields a vertical ionization energy (IE) of 10.5 eV, significantly above the calculated adiabatic IE of 8.6 eV. The cationic minimum is accessible after vertical ionization by H-transfer from one of the γ-carbons to a carbonyl oxygen and is sufficiently energetic to decay by water loss at the ionization onset. The slope of the breakdown curves, quantum chemical calculations, and selective deuteration of the carboxylic hydrogens establish the dissociative photoionization mechanism. After ionization, one γ-methylene hydrogen and the two carboxylic hydrogens are randomized prior to H2O loss. On the basis of the deuteration degree in the H2O + CO-loss product at higher energies, a direct water-loss channel without complete randomization also exists. The breakdown diagram and center of gravity of the H2O + CO-loss peak were modeled to obtain 0 K appearance energies of 10.77, 10.32, and 11.53 eV for H2O + CO loss, CH2COOH loss, and H2O + CH2COOH loss from adipic acid. These agree well with the CBS-QB3 calculated values of 10.68, 10.45, and 11.57 eV, respectively, which shows that threshold photoionization can yield energetics data as long as the dissociation is statistical, even when the parent ion cannot be observed. The results can be used as a starting point for a deeper understanding of the ionization and low-energy fragmentation of organic aerosol components. PMID:27100102

  5. Effect of dietary adipic acid and corn dried distillers grains with solubles on laying hen performance and nitrogen loss from stored excreta with or without sodium bisulfate.

    Science.gov (United States)

    Romero, C; Abdallh, M E; Powers, W; Angel, R; Applegate, T J

    2012-05-01

    Effects of dietary adipic acid (0 vs. 1%) and corn dried distillers grains with solubles (DDGS; 0 vs. 20%) were evaluated on hen performance and egg characteristics from 26 to 34 wk of age. Four isocaloric and isonitrogenous diets were randomly assigned to blocks of 6 consecutive cages (36 cages per diet; 2 hens per cage). On wk 2 and 7 of the experiment, excreta were collected by cage block, mixed, and equally split into 2 containers. Sodium bisulfate (SBS) was spread (8.8 kg/100 m(2)) on the top surface of half of the containers. All containers were stored uncovered for 14 d at room temperature. Excreta pH, DM, and N content were measured on d 0, 7, and 14 of storage. Feed intake (112 g/d per hen), egg production (96.1%), and egg specific gravity (1.079 g/g) were not affected by diet. On excreta collection day, a synergy (P = 0.014) between dietary adipic acid and DDGS was detected, as the lowest excreta pH was obtained with the diet including both adipic acid and DDGS. On d 7 of storage, excreta pH was still reduced by dietary adipic acid (P = 0.046) and DDGS (P hens fed 20% DDGS lost 19.7% more N (P = 0.039) during storage than hens not eating DDGS. Surface amendment of excreta with SBS increased excreta DM content, with the effect being even more marked on d 14 of storage (increase of 6.7 percentage units; P < 0.001), consistently decreased excreta pH during storage (P < 0.001) and reduced N loss by 26.1% for the 14 d of storage period. PMID:22499873

  6. Production and Treatment of Three Waste in Adipic Acid Prodution%己二酸生产中“三废”的产生与处理

    Institute of Scientific and Technical Information of China (English)

    董菲菲; 许小军

    2015-01-01

    From green prodution ,the causes of three waste prodution in mainstream adipic acid production at home are summarized ,the treatment method for waste gas ,waste liquid,waste solid are introduced .%从绿色生产的角度总结了目前国内主流的己二酸生产工艺中工业三废产生的原因,从废气、废液、废固三方面介绍了其相对应的处理方法。

  7. Experimental improvement of preparation for adipic acid through oxidation of potassium permanganate%高锰酸钾氧化制备己二酸的实验改进

    Institute of Scientific and Technical Information of China (English)

    徐翔宇

    2011-01-01

    通过改变高锰酸钾氧化环己醇制备己二酸的方法,使制备己二酸的实验变得简便、过程简单、反应时间缩短、产率提高、实验效果理想.%Through changing the method of the preparation for adipic acid of the potassium permanganate oxidizing cyclohexanol, the experiment of preparation for adipic acid becomes more simple and convenient. The whole process is simple, the reaction time is shortened, the yield is increased and the experimental results are very ideal.

  8. Electrospun Scaffolds from Low Molecular Weight Poly(ester amides Based on Glycolic Acid, Adipic Acid and Odd or Even Diamines

    Directory of Open Access Journals (Sweden)

    Sara Keiko Murase

    2015-05-01

    Full Text Available Electrospinning of regular poly(ester amides (PEAs constituted by glycolic acid, adipic acid and diamines with five and six carbon atoms has been carried out. Selected PEAs were constituted by natural origin products and could be easily prepared by a polycondensation method that avoids tedious protection and deprotection steps usually required for obtaining polymers with a regular sequence. Nevertheless, the synthesis had some limitations that mainly concerned the final low/moderate molecular weight that could be attained. Therefore, it was considered interesting to evaluate if electrospun scaffolds could still be prepared taking also advantage of the capability of PEAs to establish intermolecular hydrogen bonds. Results indicated that the crucial factor was the control of polymer concentration in the electrospun solution, being necessary that this concentration was higher than 40% (w/v. The PEA with the lowest molecular weight (Mw close to 8000 g/mol was the most appropriate to obtain electrospun samples with a circular cross-section since higher molecular sized polymers show solvent retention problems derived from the high viscosity of the electrospun solution that rendered ribbon-like morphologies after the impact of fibers into the collector. The studied PEAs were semicrystalline and biodegradable, as demonstrated by calorimetric and degradation studies. Furthermore, the new scaffolds were able to encapsulate drugs with anti-inflammatory and bacteriostatic activities like ketoprofen. The corresponding release and bactericide activity was evaluated in different media and against different bacteria. Finally, biocompatibility was demonstrated using both fibroblast and epithelial cell lines.

  9. The mechanics of hyaluronic acid/adipic acid dihydrazide hydrogel: towards developing a vessel for delivery of preadipocytes to native tissues.

    Science.gov (United States)

    Shoham, Naama; Sasson, Aviad Levi; Lin, Feng-Huei; Benayahu, Dafna; Haj-Ali, Rami; Gefen, Amit

    2013-12-01

    Promising treatment approaches in repairing tissue defects include implementation of regenerative medicine strategies, particularly delivery of preadipocytes to sites where adipose tissue damage needs to be repaired or where fat needs to be generated. In this study, we suggest that the injectable hyaluronic acid/adipic acid dihydrazide (HA/ADH) hydrogel may be an adipose-tissue-like material in terms of biological compatibility as well as mechanical behavior. First, we show that the hydrogel enables and supports growth, proliferation and differentiation of 3T3-L1 preadipocytes. Second, given that adipose tissue is a weight-bearing biological structure, we investigate the large deformation mechanical behavior of the hydrogel with and without embedded preadipocytes, by performing confined and unconfined compression tests and then calibrating a strain energy density (SED) function to the results. Four test groups were examined: (1) Hydrogel specimens right after the preparation without cells, (2) and (3) 3-days-cultured hydrogel specimens with and without cells, respectively, and (4) 6-days-cultured hydrogel specimens with cells. A one-term Ogden SED was found to adequately describe the hyperelastic behavior of the hydrogel specimens in all experimental groups. Importantly, we found that the mechanical properties of the hydrogel, when subjected to compression, are in good agreement with those of native adipose tissue, with the better fit occurring 3-6 days after preparation of the hydrogel. Third, computational finite element studies of the mechanical (stress-strain) behavior of the HA/ADH hydrogel when containing mature adipocytes indicated that the stiffnesses of the constructs were mildly affected by the presence of the adipocytes. Hence, we conclude that injectable HA/ADH hydrogel may serve as a vessel for protecting preadipocytes during, and at a short-term after delivery to native tissues, e.g. in research towards regenerative medicine in tissue reconstructions.

  10. Catalytic oxidation of cyclohexanone to adipic acid catalysed by supported phosphotungstic acid%固载磷钨酸催化氧化环己酮合成己二酸

    Institute of Scientific and Technical Information of China (English)

    叶天旭; 马雪妮; 刘京燕

    2009-01-01

    Adipic acid was synthesized via oxidation of cyclohexanone using phosphotungstic acid (H3PW12O40)/Al2O3 as the catalyst and 30% H2O2 as the oxidant. The influence of reaction condition on the yield of adipic acid was investigated. The optimum reaction condition was obtained as follows: n (hydrogen peroxide): n (phosphoric acid ): n (cyclohexanone)=4.4:0.99:1 ,n( phosphotungstic acid):n(cyclohexanone) =1:290, reaction at 75℃ for 1 h and then at 93℃ for7 h. Adipic acid yield of 95.5% was attained using with phosphoric acid as the promoter. Strength of the supported catalyst was enhanced by introduction of lanthanum.%以氧化铝固载的磷钨酸为催化剂,30%过氧化氢为氧化剂,催化氧化环己酮合成己二酸.考察反应条件对己二酸收率的影响,得到最佳工艺条件:n(过氧化氢)∶n(磷酸)∶n(环己酮)=4.4∶0.99∶1,n(磷钨酸)∶n(环己酮)=1∶290,75℃反应1 h,再于93℃反应7 h,加入磷酸助剂,己二酸收率达95.5%.采用镧改性氧化铝固载磷钨酸,固载强度高.

  11. Biodegradation of poly(lactic acid), poly(hydroxybutyrate-co-hydroxyvalerate), poly(butylene succinate) and poly(butylene adipate-co-terephthalate) under anaerobic and oxygen limited thermophilic conditions

    OpenAIRE

    Jutakan Boonmee; Charnwit Kositanont; Thanawadee Leejarkpai

    2016-01-01

    In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid) (PLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), poly(butylene succinate) (PBS), and poly(butylene adipate-co-terephthalate) (PBAT) were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of b...

  12. Heat Treatment Effects on the Mechanical Properties and Morphologies of Poly (Lactic Acid/Poly (Butylene Adipate-co-terephthalate Blends

    Directory of Open Access Journals (Sweden)

    Hsien-Tang Chiu

    2013-01-01

    Full Text Available In this study the relationships between mechanicals properties and morphology of the poly (lactic acid (PLA/poly (butylene adipate-co-terephthalate (PBAT blends with or without heat treatment were investigated. The differential scanning calorimetry (DSC analysis showed that blends have a two-phase structure indicating that they are immiscible. On the other hand, the PLA/PBAT (30/70 blend achieved the best tensile and impact strength because of its sea-island morphology, except for high PBAT content. The PLA/PBAT (70/30 and PLA/PBAT (50/50 blends showed irregular and directive-layer morphologies, in scanning electron microscopy (SEM analysis, producing a break cross-section with various fiber shapes. Both blends showed lower tensile strength and impact strength than the PLA/PBAT (30/70. After heat treatment, the PLA/PBAT blends showed high modulus of tensile and HDT because of a high degree of crystallization. The high degree of crystallization in the blends, which originated in the heat treatment, reduced their impact strength and elongation. However, the effect of high degree of crystallization on the PLA/PBAT (30/70 blend was small because of its sea-island morphology.

  13. Novel electrospun nanofibrous matrices prepared from poly(lactic acid)/poly(butylene adipate) blends for controlled release formulations of an anti-rheumatoid agent.

    Science.gov (United States)

    Siafaka, Panoraia I; Barmbalexis, Panagiotis; Bikiaris, Dimitrios N

    2016-06-10

    In the present work, a series of novel formulations consisting of poly(lactic acid)/poly(butylene adipate) (PLA/PBAd) electrospun blends was examined as controlled release matrices for Leflunomide's active metabolite, Teriflunomide (TFL). The mixtures were prepared using different ratios of PLA and PBAd in order to produce nanofibrous matrices with different characteristics. Miscibility studies of the blended polymeric fibers were performed through differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). Hydrolytic degradation in the prepared fibers was evaluated at 37°C using a phosphate buffered saline solution. Different concentrations of (TFL) (5, 10, 15wt.%) were incorporated into nanofibers for examining the drug release behavior in simulated body fluids (SBF), at 37°C. The drug-loaded nanofibrous formulations were further characterized by Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy, DSC and XRD. Gel permeation chromatography (GPC) analysis was used to evaluate the mechanism of TFL release. Artificial neural networks (ANN) and multi-linear-regression (MLR) models were used to evaluate the effect of % content of PBAd (X1) and TFL (X2) on an initial burst effect and a dissolution behavior. It was found that PLA/PBAd nanofibers have different diameters depending on the ratio of used polyesters and added drug. TFL was incorporated in an amorphous form inside the polymeric nanofibers. In vitro release studies reveal that a drug release behavior is correlated with the size of the nanofibers, drug loading and matrix degradation after a specific time. ANN dissolution modeling showed increased correlation efficacy compared to MLR. PMID:27039136

  14. 78 FR 33748 - Diisopropyl Adipate; Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2013-06-05

    ... In the Federal Register of August 22, 2012 (77 FR 50661) (FRL-9358- 9), EPA issued a notice pursuant... conservative. Diisopropyl adipate is a large molecular weight compound compared to adipic acid. Converting...., textiles (clothing and diapers), carpets, swimming pools, and hard surface disinfection on walls,...

  15. Influence of acids composition in the properties of poly(glycerol citrate-co-adipate); Influencia da composicao dos acidos nas propriedades do poli(glicerol citrato-co-adipato)

    Energy Technology Data Exchange (ETDEWEB)

    Brioude, M.M.; Pereira, R.; Fiuza, R.P.; Jose, N.M., E-mail: mbrioude@gmail.co [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica

    2010-07-01

    Synthetic polymers are highly resistant to degradation, being one of the greatest responsible for environment pollution. Consequently, an increase in biodegradable polymers research and development is happening. In this work we propose the synthesis and characterization of polyesters potentially biodegradable using glycerol, citric acid (CA) and adipic acid (AD). The polyesters were prepared by adding the reactants in molar ratio between glycerol:acids (1:1,5), but changing the acids ratio. The system was heated to 150-160 deg C, under nitrogen atmosphere and magnetic stirring, without catalyst adding. The samples were characterized by TGA, DSC, FTIR, XRD e SEM. The results show that the polymers prepared are amorphous polyesters, with two thermal events in 250 deg C and 450 deg C and the surfaces presents smooth and rough regions refers to bonds between glycerol and CA or AD, respectively. (author)

  16. 工业级己二酸无机杂质元素的光谱研究%Study on Determination of Inorganic Impurity Elements in Industrial Grade Adipic Acid by Inductively Coupled Plasma Optical Emission Spectrometry

    Institute of Scientific and Technical Information of China (English)

    马宁; 谢华林; 欧竞; 符靓

    2014-01-01

    An analytical method for determination of Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Cu, Zn and Pb in industrial grade adipic acid by using inductively coupled plasma optical emission spectrometry (ICP-OES) was established. The adipic acid was dissolved with HNO3, then the above 12 inorganic impurity elements in the solution were analyzed directly by ICP-OES. The working parameters of the instrument were optimized. Appropriate analysis line of various elements was selected. Y as internal standard element was used to compensate matrix effect and signal drift. Under the optimal conditions, the detection limits was 0.56~18.20µg/L, the recoveries of standard addition was in the range of 92.96%~107.90%and the RSD was 0.8%~3.3%. This method was simple, sensitive and precise, and was suitable for the determination of inorganic impurity elements in industrial grade adipic acid.%建立工业级己二酸中多个无机杂质元素的快速光谱分析方法。己二酸样品经硝酸溶解后直接用电感耦合等离子体发射光谱(ICP-OES)法测定其中的Na、Mg、Al、K、Ca、V、Cr、Mn、Fe、Cu、Zn、Pb等12种无机杂质元素。通过优化仪器工作参数,选择最佳的分析波长,并以Y为内标元素消除了测定过程中的光谱干扰和基体效应。在优化的实验条件下,方法的检出限为0.56~18.20µg·L-1,各元素的加标回收率为92.96%~107.90%,RSD为0.8%~3.3%。方法可实现工业级己二酸中无机杂质元素的快速准确测定。

  17. 己二酸-1,4-丁二醇-尿素共聚物的合成与表征%Synthesis, characterization of adipic acid-l, 4-butanediol-urea copolymer

    Institute of Scientific and Technical Information of China (English)

    刘跃军; 谢伟; 刘亦武; 刘磅

    2012-01-01

    A novel adipic acid copolymer was synthesized via condensation polymerization with adipic acid, urea and, 1,4-butanediol as the raw materials. The influences of reaction time, catalyst, mass ratio of raw materials and the temperature on the property of copolymer were investigated. The structure, thermodynamic perform- ance and the molecular weights of the eopolymer were characterized by fourier transform infrared (FT-IR), 1 H- NMR spectrum, gel permeation chromatography (GPG) and thermogravimeter-differential scanning calorimeter (TG-DSC) respectively. The results show that under the condition of 220℃, 10h, the optimal feed molar ratios n (1,4-butanediol and urea)/n (adipic acid) == 1.16 : 1, n (adipie acid)/n (urea) = 5 : 1, the amount of catalyst was 0.03wt %), a desired adipic acid copolymer whose weight-average molecular weight reaches 12700 could be obtained. The prepared copolymer has higher thermostability, degradability and good appearance.%以己二酸、1,4-丁二醇和尿素为原料,在氩气环境下,通过高温熔融缩聚反应合成了一种新型可降解的己二酸-丁二醇-尿素共聚物,并对反应时间、催化剂种类及其用量、原料配比、反应温度等因素对聚合产物的影响进行了研究。采用红外光谱(FT-IR)、核磁共振(1H-NMR)、凝胶渗透色谱(GPC)、热重分析(TG)、差示量热扫描(DSC)对产物的结构与性能进行了表征。结果表明,当丁二醇和尿素的总量与己二酸(n(丁二醇+尿素)∶n(己二酸))的摩尔比为1.16∶1,丁二醇和尿素(n(1,4-丁二醇)∶n(尿素))的摩尔比为5∶1,最高反应温度为220℃,二月桂酸二丁基锡为催化剂且用量为原料总量的0.03%,总反应时间10h,所得到产物的重均分子量(Mw)可达12700,其颜色、热稳定性和降解性能等较好。

  18. Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

    Directory of Open Access Journals (Sweden)

    Jutakan Boonmee

    2016-01-01

    Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

  19. Pepper protein phosphatase type 2C, CaADIP1 and its interacting partner CaRLP1 antagonistically regulate ABA signalling and drought response.

    Science.gov (United States)

    Lim, Chae Woo; Lee, Sung Chul

    2016-07-01

    Abscisic acid (ABA) is a key phytohormone that regulates plant growth and developmental processes, including seed germination and stomatal closing. Here, we report the identification and functional characterization of a novel type 2C protein phosphatase, CaADIP1 (Capsicum annuum ABA and Drought-Induced Protein phosphatase 1). The expression of CaADIP1 was induced in pepper leaves by ABA, drought and NaCl treatments. Arabidopsis plants overexpressing CaADIP1 (CaADIP1-OX) exhibited an ABA-hyposensitive and drought-susceptible phenotype. We used a yeast two-hybrid screening assay to identify CaRLP1 (Capsicum annuum RCAR-Like Protein 1), which interacts with CaADIP1 in the cytoplasm and nucleus. In contrast to CaADIP1-OX plants, CaRLP1-OX plants displayed an ABA-hypersensitive and drought-tolerant phenotype, which was characterized by low levels of transpirational water loss and increased expression of stress-responsive genes relative to those of wild-type plants. In CaADIP1-OX/CaRLP1-OX double transgenic plants, ectopic expression of the CaRLP1 gene led to strong suppression of CaADIP1-induced ABA hyposensitivity during the germinative and post-germinative stages, indicating that CaADIP1 and CaRLP1 act in the same signalling pathway and CaADIP1 functions downstream of CaRLP1. Our results indicate that CaADIP1 and its interacting partner CaRLP1 antagonistically regulate the ABA-dependent defense signalling response to drought stress. PMID:26825039

  20. Synthesis and structural characterization of zirconium phosphate adipate dimethyl sulphoxide: A new lambda-type organic-inorganic layered material

    Indian Academy of Sciences (India)

    Hussein Alhendawi

    2014-07-01

    −Zirconium phosphate adipate dimethyl sulphoxide, -ZrPO4(OOC-(CH2)4-COOH)(CH3)2SO, is prepared by means of topotactic anion exchange of the chloride ligand of -Zirconium phosphate, -ZrPO4Cl(CH3)2SO, with adipate. The samples are characterized by thermal analyses, X-ray diffractometry and FT-IR spectrophotometry. The used analysis approaches provide strong evidence that the chloride monovalent anions of -Zirconium phosphate are completely exchanged with the carboxylate groups of the adipate monoanionic ligands. Moreover, the adipate ligands replace the chloride anions in a 1:1 stoichiometry. In this case the formula of the derivative should contain the monoanionic adipate fragment: (OOC-(CH2)4-COOH). This formula is in agreement with TGA and elemental analysis. With respect to intercalation properties, the synthesized adipate-solid phase has a higher acidic character and a larger gallery height in comparison to the pristine -Zirconium phosphate (1.47, 1.02 nm, respectively). Therefore, this material is expected to be a suitable host for intercalation of huge basic guests.

  1. Effect of Alcohol Structure on the Optimum Condition for Novozym 435-Catalyzed Synthesis of Adipate Esters

    Directory of Open Access Journals (Sweden)

    Mohd Basyaruddin Abdul Rahman

    2011-01-01

    Full Text Available Immobilized Candida antarctica lipase B, Novozym 435, was used as the biocatalyst in the esterification of adipic acid with four different isomers of butanol (n-butanol, sec-butanol, iso-butanol, and tert-butanol. Optimum conditions for the synthesis of adipate esters were obtained using response surface methodology approach with a four-factor-five-level central composite design concerning important reaction parameters which include time, temperature, substrate molar ratio, and amount of enzyme. Reactions under optimized conditions has yielded a high percentage of esterification (>96% for n-butanol, iso-butanol, and sec-butanol, indicating that extent of esterification is independent of the alcohol structure for primary and secondary alcohols at the optimum conditions. Minimum reaction time (135 min for achieving maximum ester yield was obtained for iso-butanol. The required time for attaining maximum yield and also the initial rates in the synthesis of di-n-butyl and di-sec-butyl adipate were nearly the same. Immobilized Candida antarctica lipase B was also capable of esterifying tert-butanol with a maximum yield of 39.1%. The enzyme is highly efficient biocatalyst for the synthesis of adipate esters by offering a simple production process and a high esterification yield.

  2. Effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture Efeito da suplementação com ácido linoléico conjugado sobre a atividade da lípase lipoprotéica em cultura de adipócitos 3T3-L1

    Directory of Open Access Journals (Sweden)

    Adriana Prais Botelho

    2009-10-01

    Full Text Available Supplementation with conjugated linoleic acid may reduce fat body mass and increase lean body mass in various species. Some studies have demonstrated that conjugated linoleic acid reduces body fat, in part, by inhibiting the activity of lipoprotein lipase in adipocytes. The objective of this work was to study the effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture. 3T3-L1 adipocytes received linoleic acid (group C or conjugated linoleic acid (group AE, supplemented with AdvantEdge® CLA, and group CO, supplemented with CLA One® in concentrations of 1 mmol/L. Heparin-releasable lipoprotein lipase activity was analyzed by means of a 3T3-L1 adipocyte culture. After 7 days, heparin-releasable lipoprotein lipase activity was lower in the groups AE and CO supplemented with conjugated linoleic acid. These results suggest that one of the mechanisms by which CLA is capable of reducing body fat is by reducing lipoprotein lipase activity.A suplementação com ácido linoléico conjugado pode reduzir a gordura corporal e aumentar a massa magra em diferentes espécies. Alguns estudos têm demonstrado que o ácido linoléico conjugado reduz a gordura corporal, por meio da inibição da atividade de lípase lipoprotéica em adipócitos. O objetivo deste estudo foi avaliar o efeito da suplementação com uma mistura de isômeros do ácido linoléico conjugado sobre a atividade da lípase lipoprotéica em cultura de adipócitos 3T3-L1. Os adipócitos 3T3-L1 receberam ácido linoléico (grupo controle ou ácido linoléico conjugado (grupo AE, suplementado com AdvantEdge® CLA, e grupo CO, suplementado com CLA One® na concentração de 1 mmol/L. A atividade de lípase lipoprotéica livre de heparina foi analisada pela média da cultura de adipócitos. Após 7 dias, a atividade da lípase lipoprotéica livre de heparina mostrou menores valores nos grupos AE e CO, suplementados com ácido linol

  3. Analysis of Adipate Ester Contents in PVC Plastics

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    2006-01-01

    -ethylhexyl adipate or DEHA [103-23-1], also known as Adimoll® or di-octyl adipate, DOA, see Fig. 1. A widely used plasticizer in food (cling) films is DEHA, often in combination with polymers, epoxidized soya-bean oil, etcetera. DEHA also occurs in children toys. We have previously shown that the presence...

  4. Data on synthesis of oligomeric and polymeric poly(butylene adipate-co-butylene terephthalate model substrates for the investigation of enzymatic hydrolysis

    Directory of Open Access Journals (Sweden)

    Veronika Perz

    2016-06-01

    Full Text Available The aliphatic-aromatic copolyester poly(butylene adipate-co-butylene terephthalate (PBAT, also known as ecoflex, contains adipic acid, 1,4-butanediol and terephthalic acid and is proven to be compostable [1–3]. We describe here data for the synthesis and analysis of poly(butylene adipate-co-butylene terephthalate variants with different adipic acid:terephatalic acid ratios and 6 oligomeric PBAT model substrates. Data for the synthesis of the following oligomeric model substrates are described: mono(4-hydroxybutyl terephthalate (BTa, bis(4-(hexanoyloxybutyl terephthalate (HaBTaBHa, bis(4-(decanoyloxybutyl terephthalate (DaBTaBDa, bis(4-(tetradecanoyloxybutyl terephthalate (TdaBTaBTda, bis(4-hydroxyhexyl terephthalate (HTaH and bis(4-(benzoyloxybutyl terephthalate (BaBTaBBa. Polymeric PBAT variants were synthesized with adipic acid:terephatalic acid ratios of 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50. These polymeric and oligomeric substances were used as ecoflex model substrates in enzymatic hydrolysis experiments in the article “Substrate specificities of cutinases on aliphatic-aromatic polyesters and on their model substrates” [4].

  5. Polymerization of Pyrrole and Thiophene on Polyethylene Adipate Electrodes

    OpenAIRE

    Erturan, Seyfettin; TORAMAN, Burcu YALVAÇ and Sena

    1998-01-01

    Polymerizations of pyrrole and thiophene on a platinum foil coated by polyethylene adipate (PEA) were carried out in acetonitrile by electrochemical methods. Different compositions of semi-conducting composite films of PEA/Polypyrrole(PPy), PEA/Polythiophene(PT) were prepared by the electrochemical polymerization of pyrrole and thiophene on PEA electrode. The polymerization was possible only for a certain thickness of the polyethylene adipate(PEA) on the platinum. Conductivities of PEA/PPy, P...

  6. Design, Synthesis and Characterisation of Novel Biodegradable Aliphatic Copolyesters- Poly(ethylene sebacate-co-butylene succinate and Poly(ethylene sebacate-co-butylene adipate

    Directory of Open Access Journals (Sweden)

    L. SOWBAGYALAKSHMI PRABHA

    2012-12-01

    Full Text Available Synthesis of novel aliphatic biodegradable copolyesters namely Poly (ethylene sebacate-co-butylene succinate and Poly (ethylene sebacate-co-butylene adipate were carried out using Poly (butylene Succinate, Poly (Butylene Adipate and Poly (Ethylene Sebacate in presence of Poly Phosphoric acid. Synthesis of Poly (Butylene Succinate, Poly (Butylene Adipate and Poly (Ethylene Sebacate were carried out using respective diols and diacids in presence of titanium tetrabutoxide as catalyst. Newly synthesized copolyesters were characterized by solubility studies, viscosity measurements, thermal analysis, IR Spectroscopy and Nuclear Magnetic Resonance Spectroscopy (1H-NMR and 13C-NMR. The characteristic peaks present in the homopolyesters were recorded in the copolymers as well. DSC analysis of the copolyesters showed multiple melting peaks, while increase of methylene units in the di-acid decreased the Tg.

  7. Poly(lactide)-g-poly(butylene succinate-co-adipate) with High Crystallization Capacity and Migration Resistance

    OpenAIRE

    Xi Yang; Huan Xu; Karin Odelius; Minna Hakkarainen

    2016-01-01

    Plasticized polylactide (PLA) with increased crystallization ability and prolonged life-span in practical applications due to the minimal plasticizer migration was prepared. Branched plasticized PLA was successfully obtained by coupling poly(butylene succinate-co-adipate) (PBSA) to crotonic acid (CA) functionalized PLA. The plasticization behavior of PBSA coupled PLA (PLA-CA-PBSA) and its counterpart PBSA blended PLA (PLA/PBSA) were fully elucidated. For both PLA-CA-PBSA and PLA/PBSA, a decre...

  8. Toxicological investigation of di(2-ethylhexyl)adipate in rats

    NARCIS (Netherlands)

    Jansen EHJM; van den Ham WA; de Fluiter P; van Leeuwen FXR

    1993-01-01

    In a study in which male rats have been exposed to 0, 200, 600, 2000, 6000 and 20000 mg di(2-ethylhexyl)adipate (DEHA)/kg diet for 2 weeks, body weight and liver weight and a number of enzyme parameters which are related with peroxisome proliferation (palmitoyl coenzyme-A oxidase (PCO), enoyl coenzy

  9. 40 CFR 721.8079 - Isophorone diisocyanate neopentyl glycol adipate polyurethane prepolymer.

    Science.gov (United States)

    2010-07-01

    ... glycol adipate polyurethane prepolymer. 721.8079 Section 721.8079 Protection of Environment ENVIRONMENTAL... adipate polyurethane prepolymer. (a) Chemical substance and significant new uses subject to reporting. (1... polyurethane prepolymer (PMN P-94-1743) is subject to reporting under this section for the significant new...

  10. Synthesis, Characterization, and Biodegradation Studies of Poly(1,4-cyclohexanedimethylene-adipate-carbonates

    Directory of Open Access Journals (Sweden)

    Ajay S. Chandure

    2014-01-01

    Full Text Available Aliphatic/alicyclic poly(1,4-cyclohexanedimethylene-adipate-carbonates (PCACs were synthesized by a transesterification from 1,4-cyclohexamethylendimethanol (1,4-CHDM, adipic acid (AA, diethyl carbonate (DEC, and titanium butoxide Ti(OBu4 as a transesterification catalyst. The synthesized PCACs were characterized by the Fourier transform infrared (FTIR, X-ray diffraction analysis (XRD, solubility, solution viscosity, gel permeation chromatography (GPC, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, and scanning electron microscope (SEM for their structural, physical, thermal, and morphological investigation. The structure of synthesized PCACs was confirmed by FTIR. All TGA curves of PCACs shows 10% weight loss above 270°C, and they reveal good thermal stability. Biodegradability of PCACs was investigated by hydrolytic degradation at (pH 7.2 and 11.5, enzymatic degradation using Rhizopus delemar lips at 37°C in phosphate buffer solution (PBS, and soil burial degradation at 30°C. The hydrolytic degradation shows the greater rate of weight loss in PBS at pH-11.5 than pH-7.2. The hydrolytic and soil burial degradation shows faster rate of weight loss as compared to enzymatic degradation. Biodegradation rate of PCACs follows the order: PCAC-20 > PCAC-40 > PCAC-60. SEM images show that degradation occurred all over the film surface, creating holes and cracks. These biodegradable PCACs may be able to replace conventional polymer in the fabrication of packaging film in near future.

  11. In vitro release of clomipramine HCl and buprenorphine HCl from poly adipic anhydride (PAA) and poly trimethylene carbonate (PTMC) blends.

    Science.gov (United States)

    Dinarvand, Rassoul; Alimorad, Mohammed Massoud; Amanlou, Massoud; Akbari, Hamid

    2005-10-01

    Controlled drug-delivery technology is concerned with the systematic release of a pharmaceutical agent to maintain a therapeutic level of the drug in the body for modulated and/or prolonged periods of time. This may be achieved by incorporating the therapeutic agent into a degradable polymer vehicle, which releases the agent continuously as the matrix erodes. In this study, poly trimethylene carbonate (PTMC), an aliphatic polycarbonate, and poly adipic anhydride (PAA), an aliphatic polyanhydride, were synthesized via melt condensation and ring-opening polymerization of trimethylene carbonate and adipic acid, respectively. The release of clomipramine HCl and buprenorphine HCl from discs prepared with the use of PTMC-PAA blends in phosphate buffer (pH 7.4) are also described. Clomipramine HCl and buprenorphine HCl were both used as hydrophilic drug models. Theoretical treatment of the data with the Peppas model revealed that release of clomipramine HCl (5%) in devices containing 70% PTMC or more followed a Fickian diffusion model. However, the releases of buprenorphine HCl (5%) in the same devices were anomalous. For devices containing 50% and more PAA, surface erosion may play a significant role in the release of both molecules.

  12. Influence of the adipate and dissolved oxygen concentrations on the beta-lactam production during continuous cultivations of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus

    DEFF Research Database (Denmark)

    Robin, Jarno Jacky Christian; Bonneau, S.; Schipper, D.;

    2003-01-01

    The influence of adipate concentration and dissolved oxygen on production of adipoyl-7-aminodeacetoxycephalosporanic acid (ad-7-ADCA) by a recombinant strain of Penicillium chrysogenum expressing the expandase gene from Streptomyces clavuligerus was studied in glucose-limited continuous cultures....... decreased from 15 to 7%AS, r(p) (total) increased to 25 mumol g DW-1 h(-1), mainly due to a two-fold increase in the adipoyl-6-aminopenicillanic acid (ad-6-APA) specific productivity....

  13. Development of silver/titanium dioxide/chitosan adipate nanocomposite as an antibacterial coating for fruit storage

    Science.gov (United States)

    A novel nanocomposite of silver/titanium dioxide/chitosan adipate (Ag/TiO2/CS) was developed through photochemical reduction using a chitosan adipate template. Chitosan served as a reducing agent for the metal ions, and anchored metal ions by forming Ag–N coordination bonds and electrostatic attract...

  14. Metabolic network analysis of an adipoyl-7-ADCA-producing strain of Penicillium chrysogenum: Elucidation of adipate degradation

    DEFF Research Database (Denmark)

    Thykær, Jette; Christensen, Bjarke; Nielsen, Jens

    2002-01-01

    An adipoyl-7-ADCA-producing, recombinant strain of Penicillium chrysogenum was characterized by metabolic network analysis, with special focus on the degradation of adipate and determination of the metabolic fluxes. Degradation of the side-chain precursor, adipate, causes an undesired consumption...

  15. Development of poly(glycerol adipate) nanoparticles loaded with non-steroidal anti-inflammatory drugs.

    NARCIS (Netherlands)

    Wahab, A.; Favretto, M.E.; Onyeagor, N.D.; Khan, G.M.; Douroumis, D.; Casely-Hayford, M.A.; Kallinteri, P.

    2012-01-01

    The aim of this study was to assess acylated and non-acylated poly(glycerol adipate) polymers (PGA) as suitable nanoparticulate systems for encapsulation and release of ibuprofen, ibuprofen sodium salt (IBU-Na) and ketoprofen as model drugs. Drug encapsulated nanoparticles were prepared using the in

  16. Effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture Efeito da suplementação com ácido linoléico conjugado sobre a atividade da lípase lipoprotéica em cultura de adipócitos 3T3-L1

    OpenAIRE

    Adriana Prais Botelho; Lilia Ferreira Santos-Zago; Admar Costa de Oliveira

    2009-01-01

    Supplementation with conjugated linoleic acid may reduce fat body mass and increase lean body mass in various species. Some studies have demonstrated that conjugated linoleic acid reduces body fat, in part, by inhibiting the activity of lipoprotein lipase in adipocytes. The objective of this work was to study the effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture. 3T3-L1 adipocytes received linoleic acid (group C) or conjugated linole...

  17. ANALYSIS OF ADIPATE ESTER CONTENTS IN POLY(VINYL CHLORIDE) PLASTICS

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Otero, Amalia Dopazo

    2006-01-01

    Fourier transform (FT-) Raman spectroscopy excited with a 1064 nm laser can be used to determine the content of plasticizers in commercial flexible poly vinyl chloride (PVC) products. Our previous study [T. Nørbygaard, R.W. Berg, Analysis of phthalate ester content in PVC plastics by means of FT......-Raman Spectroscopy, Appl. Spectrosc. 58 (4) (2004) 410–413]—on detection of the presence of phthalate esters in PVC by FT-Raman spectroscopy — is here extended to the similar case of adipate esters (AEs) in samples of soft poly vinyl chloride plastics. Spectra of a range of adipate ester plasticizers (11 AEs...... dicarboxylic esters have very similar bands. This limits the detection as to what kind of ester and how much is present in a sample. An essential finding was however that one can use the absence of any Raman band in the 1020–1060 cm-1 range of the adipate esters, as a means to verify that a given soft PVC...

  18. Catalytic routes towards acrylic acid, adipic acid and epsilon-caprolactam starting from biorenewables

    NARCIS (Netherlands)

    R. Beerthuis; G. Rothenberg; N.R. Shiju

    2015-01-01

    The majority of bulk chemicals are derived from crude oil, but the move to biorenewable resources is gaining both societal and commercial interest. Reviewing this transition, we first summarise the types of today's biomass sources and their economical relevance. Then, we assess the biobased producti

  19. Poly(lactide-g-poly(butylene succinate-co-adipate with High Crystallization Capacity and Migration Resistance

    Directory of Open Access Journals (Sweden)

    Xi Yang

    2016-04-01

    Full Text Available Plasticized polylactide (PLA with increased crystallization ability and prolonged life-span in practical applications due to the minimal plasticizer migration was prepared. Branched plasticized PLA was successfully obtained by coupling poly(butylene succinate-co-adipate (PBSA to crotonic acid (CA functionalized PLA. The plasticization behavior of PBSA coupled PLA (PLA-CA-PBSA and its counterpart PBSA blended PLA (PLA/PBSA were fully elucidated. For both PLA-CA-PBSA and PLA/PBSA, a decrease of Tg to around room temperature and an increase in the elongation at break of PLA from 14% to 165% and 460%, respectively, were determined. The crystallinity was increased from 2.1% to 8.4% for PLA/PBSA and even more, to 10.6%, for PLA-CA-PBSA. Due to the inherent poor miscibility between the PBSA and PLA, phase separation occurred in the blend, while PLA-CA-PBSA showed no phase separation which, together with the higher crystallinity, led to better oxygen barrier properties compared to neat PLA and PLA/PBSA. A higher resistance to migration during hydrolytic degradation for the PLA-CA-PBSA compared to the PLA/PBSA indicated that the plasticization effect of PBSA in the coupled material would be retained for a longer time period.

  20. 21 CFR 178.3690 - Pentaerythritol adipate-stearate.

    Science.gov (United States)

    2010-04-01

    ... not to exceed 15 as determined by ASTM method D1386-78, “Standard Test Method for Saponification...) Saponification number of 270-280 as determined by ASTM method D1387-78, “Standard Test Method for Acid...

  1. The liquid–liquid coexistence curves of {x dimethyl adipate + (1 − x) n-hexane} and {x dimethyl adipate + (1 − x) n-heptane} in the critical region

    International Nuclear Information System (INIS)

    Highlights: ► Coexistence curves of (dimethyl adipate + n-hexane) (+n-heptane) were measured. ► The critical exponent β are consistent with the 3D-Ising value. ► The asymmetry of the coexistence curves were discussed by complete scaling theory. - Abstract: The liquid–liquid coexistence curves for (dimethyl adipate + n-hexane), (dimethyl adipate + n-heptane) have been measured, from which the critical amplitudes and the critical exponents are deduced. The critical exponent β corresponding to the coexistence curves are consistent with the 3D-Ising value. The experimental results have also been analyzed to determine the critical amplitudes of Wegner-correction terms when β and Δ are fixed at their theoretical values, and to examine the asymmetry of the diameters for the coexistence curves.

  2. Determination of organic acids evolution during apple cider fermentation using an improved HPLC analysis method

    NARCIS (Netherlands)

    Zhang, H.; Zhou, F.; Ji, B.; Nout, M.J.R.; Fang, Q.; Zhang, Z.

    2008-01-01

    An efficient method for analyzing ten organic acids in food, namely citric, pyruvic, malic, lactic, succinic, formic, acetic, adipic, propionic and butyric acids, using HPLC was developed. Boric acid was added into the mobile phase to separate lactic and succinic acids, and a post-column buffer solu

  3. Antiandrogenic effects in male rats perinatally exposed to a mixture of di(2-ethylhexyl) phthalate and di(2-ethylhexyl) adipate

    DEFF Research Database (Denmark)

    Jarfelt, K.; Dalgaard, M.; Hass, Ulla;

    2005-01-01

    Di(2-ethylhexyl) phthalate (DEHP) is a well-known testicular toxicant inducing adverse effects in androgen responsive tissues. Therefore, di(2-ethylhexyl) adipate (DERA) is currently being evaluated as a potential substitute for DEHP. Similarities in structure and metabolism of DERP and DEHA have...

  4. Cellulose nanocrystal and poly[di(ethylene glycol) adipate] blend for tunable lens

    Science.gov (United States)

    Ko, Hyun-U.; Kim, Hyun Chan; Li, Yaguang; Kim, Sang Youn; Kim, Jaehwan

    2016-04-01

    In these days, consumer electronics and medical device for optical diagnosis are minimalized and mobilized. The focusing part is one of crucial parts of optical diagnosis systems to reduce the size and weight. Thus, demand for tunable lens that change the focus itself is increased. To meet the demand, many tunable lens has been studied by utilizing smart materials that responded under mechanical, magnetic, optical, thermal, chemical, electrical or electrochemical stimuli. This paper reports a cellulose nanocrystal (CNC) and poly[di(ethylene glycol) adipate] (PDEGA) blend that is able to respond under electromechanical stimulus. The preparation of CNC/PDEGA and its characterization are illustrated and its actuation behavior is tested . Because the material has high dielectric constant and high reflection index, it is good candidate material for tunable lens.

  5. Poly(butylene succinate-co-butylene adipate)/cellulose nanocrystal composites modified with phthalic anhydride.

    Science.gov (United States)

    Zhang, Xuzhen; Zhang, Yong

    2015-12-10

    As a kind of biomass nanofiller for polymers, cellulose nanocrystal (CNC) has good mechanical properties and reinforcing capability. To improve the compatibility of poly(butylene succinate-co-butylene adipate) (PBSA)/CNC composites, phthalic anhydride was used as a compatilizer during melt mixing, leading to the significant improvement of the mechanical properties and thermal stability of the composites, which is related to the better dispersion of CNC in the composites. The addition of phthalic anhydride could accelerate the crystallization of PBSA component as evidenced by the curves of isothermal crystallization of the composites, but had little effect on the crystalline polymorphs of PBSA component. The addition of phthalic anhydride could strongly improve the hydrophobicity of the composites. The good mechanical properties, fast crystallization and improved hydrophobicity of PBSA/CNC composites with phthalic anhydride are favor to their practical commercial utilization.

  6. Influence of Teflon substrate on crystallization and enzymatic degradation of polymorphic poly(butylene adipate)

    DEFF Research Database (Denmark)

    Ning, Zhenbo; Nielsen, Ronnie Bo Højstrup; Zhao, Lifen;

    2014-01-01

    Oriented and non-oriented Teflon films, which were found to have the same crystalline structure, but different surface morphologies, were used to sandwich poly(butylene adipate) (PBA) films during isothermal crystallization. It was found that both the Teflon surface structure and the PBA...... polymorphic structure are the determining factors to induce epitaxial crystallization. The oriented Teflon film was able to induce epitaxial crystallization of PBA alpha crystal, while the non-oriented Teflon did not induce any epitaxial crystallization of PBA. Epitaxial crystallization did not occurred for...... PBA beta crystals between neither the oriented nor the non-oriented Teflon films. The enzymatic degradation rate of PBA films was not determined by the epitaxial crystallization, in fact it was still dependent on the polymorphic crystal structure of PBA. The morphological changes of PBA films after...

  7. Electron beam-induced crosslinking of poly(butylene adipate-co-terephthalate)

    International Nuclear Information System (INIS)

    Biodegradable poly(butylene adipate-co-terephthalate) (PBAT) was crosslinked by electron beam irradiation and their properties were investigated in this research. PBAT films prepared by a solution casting method were crosslinked by electron beam under various absorbed doses ranging 20-200 kGy and their properties were characterized by using a crosslinking degree measurement, a thermogravimetric analyzer (TGA), universal testing machine (UTM), dynamic mechanical analyzer (DMA), and thermal mechanical analyzer (TMA). The results of the crosslinking degree measurement revealed that the PBAT could be crosslinked by electron beam irradiation and its crosslinking degree was dependant on the absorbed dose. In addition, the results of the UTM, DMA, TMA, and TGA analyses revealed that the thermal and mechanical properties of the crosslinked PBS was much improved in comparison to those of the control PBAT.

  8. Thermodynamics Calculation and Analysis of Synthesis of Dimethyl Adipate%己二酸二甲酯合成体系的热力学估算及分析

    Institute of Scientific and Technical Information of China (English)

    杨超; 魏晓霞; 霍稳周

    2011-01-01

    The group contribution method was applied to estimate the enthalpy and entropy of adipic acid and dimethyl adipate in the specified reacting system under the standard state. The functional correlations between the heat capacity of these organic compounds and temperature were established. In addition, the Gibbs free energy and standard equilibrium constant of the reaction were calculated under different temperatures. Based on the thermodynamics analysis, it's found that the reaction can be almost carried out completely when reaching the equilibrium. Therefore the conclusion that the reaction is practicable in thermodynamics has been verified.%采用基团贡献法估算了反应体系中己二酸和已二酸二甲酯在298.15 K标准状态下的生成焓和标准熵,并且估算了这两种物质的比热容随温度变化的关系式,计算了不同温度条件下反应的焓变、吉布斯自由能变和标准平衡常数.通过对该反应体系的热力学分析发现,当达到平衡时该反应几乎可以进行到底,从而验证了该反应在热力学上的可行性.

  9. Influence of end groups in hyperbranched polyesters used as modifiers in the characteristics of epoxy thermosets cured by adipic dihydrazide

    OpenAIRE

    Serra, A; A. M. Tomuta; X. Ramis; S. De la Flor

    2013-01-01

    Mixtures of diglycidylether of bisphenol A (DGEBA) resin and different ratios of aliphatic-aromatic hyperbranched polyester (HBP) were cured by a latent curing agent, adipic dihydrazide (AH). The HBPs prepared have hydroxyl groups or 10-undecenoyl or allyl groups as chain ends. The curing mixtures were investigated by differential scanning calorimetry (DSC) to study the curing process and to evaluate the kinetic parameters of the different formulations. These studies suggest that HBPs decreas...

  10. Crystal engineering of analogous and homologous organic compounds: hydrogen bonding patterns in trimethoprim hydrogen phthalate and trimethoprim hydrogen adipate

    OpenAIRE

    Rychlewska Urszula; Francis Savarimuthu; Muthiah Packianathan; Warżajtis Beata

    2006-01-01

    Abstract Background Trimethoprim [2,4-diamino-5-(3',4',5'-trimethoxybenzyl)pyrimidine] is an antifolate drug. It selectively inhibits the bacterial dihydrofolate reductase (DHFR) enzyme. Results In the crystal structures of trimethoprim (TMP)-hydrogen phthalate (1) and trimethoprim-hydrogen adipate (2), one of the N atoms of the pyrimidine ring is protonated and it interacts with the deprotonated carboxylate oxygens through a pair of nearly parallel N-H...O hydrogen bonds to form a fork-like ...

  11. Preparation and characterization of nanocomposite of maleated poly(butylene adipate-co-terephthalate) with organoclay.

    Science.gov (United States)

    Chen, Jung-Hung; Yang, Ming-Chien

    2015-01-01

    Nanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) with montmorillonite (MMT) nanoparticles were prepared via melt blending. Natural MMT was modified by either octadecylamine (ODA) or dihexylamine (DHA). Neat PBAT was grafted with maleic anhydride via melt grafting process. Intercalation of the organoclay in the PBAT matrix was studied by X-ray diffraction (XRD). From the results of transmission electron microscope (TEM), the dispersion of ODA-modified MMT in the PBAT matrix was more homogeneous than that of neat MMT. The addition of organoclay can increase the cooling crystallization temperature of PBAT, as observed by differential scanning calorimetry (DSC). Furthermore, the results of thermogravimetric analyzer (TGA) showed that the addition of ODA-modified MMT can improve the thermal stability of PBAT nanocomposites. The tensile strength was little affected, while the Young's modulus was increased with the addition of nanoclays. The grafting of PBAT with MA resulted in improved interaction between polymer matrix and the silicate layer due to the formation of chemical/physical bonds, thus the dispersion of organoclays was enhanced. By grafting PBAT with MA, the enzymatic biodegradation of the nanocomposite was increased, while the photodegradation of PBAT was little affected. Furthermore, the transmission of water vapor was reduced by the addition of organically modified MMT. PMID:25491991

  12. Dispersion study of nanofibrillated cellulose based poly(butylene adipate-co-terephthalate) composites.

    Science.gov (United States)

    Mukherjee, Tapasi; Czaka, Michael; Kao, Nhol; Gupta, Rahul K; Choi, Hyoung Jin; Bhattacharya, Sati

    2014-02-15

    The production of lower cost bionanocomposites based on nanofibrillated cellulose (NFC) is a promising source to develop the next generation of light weight and high performance materials for a variety of defense, infrastructure and energy applications. In this study, a series of bio-nanocomposites were developed by reinforcing NFC from regenerated wood fiber into poly(butylene adipate-co-terephthalate) (PBAT) by injection molding. The incorporation of NFC in PBAT matrix (0.2-1 wt%) increased the storage modulus (G') and dynamic viscosity (η') as revealed by shear rheology, indicating a percolation threshold around 0.2-0.5 wt% region. DSC analysis showed similar trends with slight improvement of glass transition (Tg) and crystallization temperature (Tc). Percentage crystallinity, as calculated from heat of fusion equation and taking into account 100% crystallized PBAT data improved in overall. This is a fundamental study aimed at understanding the morphological, rheological and thermal evaluation of such nanocomposites for an improved dispersion of NFC as filler in the matrix. PMID:24507316

  13. Effect of Anodic Alumina Oxide Pore Diameter on the Crystallization of Poly(butylene adipate).

    Science.gov (United States)

    Sun, Xiaoli; Fang, Qunqun; Li, Huihui; Ren, Zhongjie; Yan, Shouke

    2016-04-01

    Poly(butylene adipate) (PBA) was infiltrated into the anodic alumina oxide (AAO) templates with the pore diameter of around 30, 70, and 100 nm and PBA nanotubes with different diameters were prepared. The crystallization and phase transition behavior of the obtained PBA nanotubes capped in the nanopores have been explored by using X-ray diffraction and differential scanning calorimetry. Only α-PBA crystals form in the bulk sample during nonisothermal crystallization. By contrast, predominant β-PBA crystals form in the AAO templates. The β-PBA crystals formed in the nanopores with pore diameter less than 70 nm prefer to adopt an orientation with their b-axis parallel to the long axis of the pore. During the melt recrystallization, it was found that the critical temperature (Tβ), below which pure β-crystals form, is 20 °C for bulk PBA. It drops down significantly with the pore diameter for the PBA in the AAO template. Moreover, the β-crystals in the porous template exhibit larger lattice parameters compared with the bulk crystals. By monitoring the change of β-crystals in the heating process, it was found that β-crystals in the AAO template with the pore diameter of 30 nm (D30) melt directly while the β-crystals transform to α-crystals in the template with the pore diameter of 100 nm (D100). The intensity of (020) Bragg peak of β-crystals decreases at a similar rate in both D30 and D100 but disappears at a relatively lower temperature in D30. On the other hand, the β(110) peak intensity of β-PBA crystals formed in the D100 template decreases first at slower rate before α crystals appear, and then at a faster rate once the β to α phase transition takes place. PMID:27008378

  14. Preparation and characterization of nanocomposite of maleated poly(butylene adipate-co-terephthalate) with organoclay

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jung-Hung [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Yang, Ming-Chien, E-mail: myang@mail.ntust.edu.tw [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2015-01-01

    Nanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) with montmorillonite (MMT) nanoparticles were prepared via melt blending. Natural MMT was modified by either octadecylamine (ODA) or dihexylamine (DHA). Neat PBAT was grafted with maleic anhydride via melt grafting process. Intercalation of the organoclay in the PBAT matrix was studied by X-ray diffraction (XRD). From the results of transmission electron microscope (TEM), the dispersion of ODA-modified MMT in the PBAT matrix was more homogeneous than that of neat MMT. The addition of organoclay can increase the cooling crystallization temperature of PBAT, as observed by differential scanning calorimetry (DSC). Furthermore, the results of thermogravimetric analyzer (TGA) showed that the addition of ODA-modified MMT can improve the thermal stability of PBAT nanocomposites. The tensile strength was little affected, while the Young's modulus was increased with the addition of nanoclays. The grafting of PBAT with MA resulted in improved interaction between polymer matrix and the silicate layer due to the formation of chemical/physical bonds, thus the dispersion of organoclays was enhanced. By grafting PBAT with MA, the enzymatic biodegradation of the nanocomposite was increased, while the photodegradation of PBAT was little affected. Furthermore, the transmission of water vapor was reduced by the addition of organically modified MMT. - Highlights: • Nanocomposites of PBAT and clay nanoparticles were prepared via melting blending. • Maleated PBAT/organoclays exhibited higher Young's moduli than neat PBAT/neat MMT. • The enzymatic degradation of PBAT composites was improved by maleation. • Maleation caused little effect on the photodegradation of PBAT. • Organoclays retarded the permeation of water vapor through PBAT composites.

  15. Specific migration of di-(2-ethylhexyl)adipate (DEHA) from plasticized PVC film: results from an enforcement campaign

    DEFF Research Database (Denmark)

    Petersen, Jens Højslev; Breindahl, T.

    1998-01-01

    , olive oil, followed by clean-up using size exclusion chromatography and final determination of di-(2-ethylhexyl) adipate (DEHA) by combined capillary gas chromatography and mass spectrometry (GC-MS). In the initial screening, the samples were exposed to the alternative food simulant, isooctane, and DEHA...... Units. Initially, all films were screened for the migration into isooctane (exposed 2 h at 40 degrees C) of DEHA and other potentially present low molecular weight plasticizers using full scanning mass spectrometry. Films showing a substantial migration of DEHA were further tested with olive oil...

  16. Enzymatic Synthesis and Characterization of Hydrophilic Sugar Based Polyesters and Their Modification with Stearic Acid

    Directory of Open Access Journals (Sweden)

    Muhammad Humayun Bilal

    2016-03-01

    Full Text Available Biodegradable and hydrophilic functional polyesters were synthesized enzymatically using xylitol or d-sorbitol together with divinyl adipate and lipase B from Candida antartica (CAL-B. The resulting polyesters had pendant OH-groups from their sugar units which were esterified to different degrees with stearic acid chloride. The structure and the degrees of polymerization of the resulting graft copolymers based on poly(xylitol adipate and poly(d-sorbitol adipate were characterized by 1H NMR spectroscopy and SEC. DSC, WAXS and SAXS measurements indicated that a phase separation between polymer backbone and stearoyl side chains occurred in the graft copolymers, and, additionally, the side chains were able to crystallize which resulted in the formation of a lamellar morphology. Additionally, nanoparticles of the graft copolymers in an aqueous environment were studied by DLS and negative stain TEM.

  17. in situ ring-opening polymerization of hydroxyapatite/poly(ethylene adipate)--(ethylene terephthalate) biomimetic composites

    Indian Academy of Sciences (India)

    Punnama Siriphannon; Pathavuth Monvisade

    2013-02-01

    Hydroxyapatite/poly(ethylene adipate)--poly(ethylene terephthalate) biomaterials (HAp/PEA--PET) have been prepared by ring opening polymerization (ROP) of cyclic oligo(ethylene adipate)--oligo(ethylene terephthalate) (C-OEA--C-OET) in the porous hydroxyapatite (HAp) scaffolds at 250 °C for 24 h under vacuum. The content of ROP-PEA--PET in the HAp/PEA--PET composite was about 20 wt% with the values of number average molecular weight ($\\bar{M}$n) and weight average molecular weight ($\\bar{M}$W) of 3380 and 7160 g/mol, respectively. Compressive strength and modulus of the HAp/PEA--PET composites were about 29 and 246 MPa, respectively. These mechanical properties were higher than those of the porous HAp templates and natural cancellous bone. In vitro bioactivity of the HAp/PEA--PET composites was studied by soaking in simulated body fluid (SBF) under the flowing system at the rate of 130 mL/day for 7, 14, 21 and 28 days. The formation of hydroxyapatite nanocrystals was observed on the composite surfaces through the consumption of calcium and phosphorus from the SBF solution, indicating the bioactivity of these HAp/PEA--PET composites. These results indicated the competency of HAp/PEA--PET composites for biomedical applications.

  18. 1-Phenyl-3-(quinolin-5-yl)urea as a host for distinction of phthalic acid and terephthalic ac

    Indian Academy of Sciences (India)

    Dipjyoti Kalita; Jubaraj B Baruah

    2013-03-01

    Co-crystals of 1-phenyl-3-(quinolin-5-yl)urea (1) with terephthalic acid, adipic acid; and salts of 1 with phthalic acid, -toluenesulphonic acids are prepared and structurally characterized. The reaction of phthalic acid and -toluenesulphonic acid resulted in protonation of the host 1, whereas the terephthalic acid and adipic acid interact with 1, led to cocrystals with the host 1 through hydrogen bond interactions. The hydrogen bonds that appears in the urea taps of the host molecules 1 are lost while formation of salts; in such cases anions interacts with the urea portion of the host, while in the co-crystals the hydrogen bonded urea taps are retained. The salts are yellow in colour while the co-crystals are colourless; thereby the positional isomer phthalic acid can be distinguished from the terephthalic acid.

  19. 十二水合硫酸铁铵催化合成己二酸二丁酯的工艺研究%Study on Synthesis Technology of Dibutyl Adipate Catalyzed by Ammonium Ferric Sulfate Dodecahydrate

    Institute of Scientific and Technical Information of China (English)

    迟卫军

    2009-01-01

    以十二水合硫酸铁铵为催化剂,己二酸与正丁醇为原料合成了己二酸二丁酯,讨论了醇酸物质的量比、催化剂用量、反应时间、带水剂等因素对酯化率的影响,确定了最佳工艺条件为:以0.1mol己二酸为基准,醇酸物质的量比为5.0:1,催化剂用量为5.0g,反应时间为1.0h,不用带水剂,己二酸二丁酯的酯化率为98.2%.该催化剂具有催化活性高,反应时间短,酯化率高,与目前工业中使用的硫酸相比环境污染小,对设备几乎无腐蚀等优点,且十二水合硫酸铁铵价格低廉易得,性质稳定,不溶于反应体系,是一种很有发展前景的催化剂.%With using ammonium ferric sulfate dodecahydrate as the catalyst, edipic acid and n-butyl alcohol as the raw materials, dibutyl adipate was synthesized. The effects of the amount of catalyst, reaction time, water-carrying agent and molar ratio of alcohol to acid on esterification rate were discussed and the optimal reaction conditions were obtained as follows: baaing on 0.1 mol adipie acid, the molar ratio of n-butyl alcohol to adipic acid was 5.0:1, the mass d catalyst was 5.0g, reaction time was 1.0h, no water-carrying agent required. Under these conditions, the highest esterification rate could reach 98.2%. Ammonium ferric sulfate dedecahydrate has many advantages, such as high catalytic activity, short reaction time, high esterification rate, non-corrosion and non-pollution to the environment comparing with sulfuric acid which is being used in industry at present. The catalyst is also low coat and stable, it will not dissolve in the reaction system, and it has a good developing foreground.

  20. Synthesis of biocompatible poly(ε-caprolactone-block-poly(propylene adipate copolymers appropriate for drug nanoencapsulation in the form of core-shell nanoparticles

    Directory of Open Access Journals (Sweden)

    Nanaki SG

    2011-11-01

    Full Text Available Stavroula G Nanaki1, Kostas Pantopoulos2, Dimitrios N Bikiaris11Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece; 2Lady Davis Institute for Medical Research and Department of Medicine, McGill University, Montreal, Quebec, CanadaAbstract: Poly(propylene adipate-block-poly(ε-caprolactone copolymers were synthesized using a combination of polycondensation and ring-opening polymerization of ε-caprolactone in the presence of poly(propylene adipate. Gel permeation chromatography was used for molecular weight determination, whereas hydrogen-1 nuclear magnetic resonance and carbon-13 nuclear magnetic resonance spectroscopy were employed for copolymer characterization and composition evaluation. The copolymers were found to be block while their composition was similar to the feeding ratio. They formed semicrystalline structures, while only poly(ε-caprolactone formed crystals, as shown by wide angle X-ray diffraction. Differential scanning calorimetry data suggest that the melting point and heat of fusion of copolymers decreased by increasing the poly(propylene adipate amount. The synthesized polymers exhibited low cytotoxicity and were used to encapsulate desferrioxamine, an iron-chelating drug. The desferrioxamine nanoparticles were self-assembled into core shell structures, had mean particle size <250 nm, and the drug remained in crystalline form. Further studies revealed that the dissolution rate was mainly related to the melting temperature, as well as to the degree of crystallinity of copolymers.Keywords: biocompatible polyesters, poly(ε-caprolactone, poly(propylene adipate, drug encapsulation, desferrioxamine

  1. Solder Flux Residues and Humidity-Related Failures in Electronics: Relative Effects of Weak Organic Acids Used in No-Clean Flux Systems

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    This paper presents the results of humidity testing of weak organic acids (WOAs), namely adipic, succinic, glutaric, dl-malic, and palmitic acids, which are commonly used as activators in no-clean solder fluxes. The study was performed under humidity conditions varying from 60% relative humidity ...

  2. Effect of Anorganic Substance on Physical Properties of Poly (Butylene Succinate -co- Adipate) Irradiated by Electron Beam

    International Nuclear Information System (INIS)

    Poly(butylene succinate-co-adipate), PBSA were electron beam irradiated in the presence of inorganic materials. The samples gave high gel fraction by irradiation in the presence of 2% silicon dioxide and 2% carbon black. It was found that addition of carbon black (CB) was effective for improving the heat stability of the sample. This is because of three-dimensional carbon black- polymer networks. Irradiated PBSA sheets broke immediately at 110 oC with load 6.67 kgf/cm2, while irradiated the same sample mixed with 2% carbon black did not break at the same condition. Biodegradability of crosslinked PBSA by soil burial tests was accelerated by addition of carbon black. (author)

  3. Influence of end groups in hyperbranched polyesters used as modifiers in the characteristics of epoxy thermosets cured by adipic dihydrazide

    Directory of Open Access Journals (Sweden)

    A. Serra

    2013-07-01

    Full Text Available Mixtures of diglycidylether of bisphenol A (DGEBA resin and different ratios of aliphatic-aromatic hyperbranched polyester (HBP were cured by a latent curing agent, adipic dihydrazide (AH. The HBPs prepared have hydroxyl groups or 10-undecenoyl or allyl groups as chain ends. The curing mixtures were investigated by differential scanning calorimetry (DSC to study the curing process and to evaluate the kinetic parameters of the different formulations. These studies suggest that HBPs decrease the curing rate of epoxy/AH in the case of vinyl terminated HPB, whereas OH terminated HBP accelerates the first stages and delays the lasts. The thermosets obtained showed an improvement in microhardness and impact strength without any reduction of the Tg and thermal parameters. Microparticle phase separation was observed with the undecenoyl HBP derivatives or when a 10% of allyl HBP derivative was in the formulation.

  4. Enhancement of Mechanical and Thermal Properties of Oil Palm Empty Fruit Bunch Fiber Poly(butylene adipate-co-terephtalate) Biocomposites by Matrix Esterification Using Succinic Anhydride

    OpenAIRE

    Samira Siyamak; Nor Azowa Ibrahim; Sanaz Abdolmohammadi; Wan Md Zin Bin Wan Yunus; Mohamad Zaki AB Rahman

    2012-01-01

    In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (EcoflexTM), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites’ performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence ...

  5. Effect of Fiber Esterification on Fundamental Properties of Oil Palm Empty Fruit Bunch Fiber/Poly(butylene adipate-co-terephthalate) Biocomposites

    OpenAIRE

    Mohamad Zaki AB Rahman; Wan Md Zin Wan Yunus; Nor Azowa Ibrahim; Sanaz Abdolmohammadi; Samira Siyamak

    2012-01-01

    A new class of biocomposites based on oil palm empty fruit bunch fiber and poly(butylene adipate-co-terephthalate) (PBAT), which is a biodegradable aliphatic aromatic co-polyester, were prepared using melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 wt% and characterized. Chemical treatment of oil palm empty fruit bunch (EFB) fiber was successfully done by grafting succinic anhydride (SAH) onto the EFB fiber surface, and the modified fib...

  6. Synthesis of biocompatible poly(ε-caprolactone)-block-poly(propylene adipate) copolymers appropriate for drug nanoencapsulation in the form of core-shell nanoparticles

    OpenAIRE

    Nanaki SG; Pantopoulos K; Bikiaris DN

    2011-01-01

    Stavroula G Nanaki1, Kostas Pantopoulos2, Dimitrios N Bikiaris11Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece; 2Lady Davis Institute for Medical Research and Department of Medicine, McGill University, Montreal, Quebec, CanadaAbstract: Poly(propylene adipate)-block-poly(ε-caprolactone) copolymers were synthesized using a combination of polycondensation and ring-opening polymerization of...

  7. Synthesis of biocompatible poly(ɛ-caprolactone)- block-poly(propylene adipate) copolymers appropriate for drug nanoencapsulation in the form of core-shell nanoparticles

    OpenAIRE

    Bikiaris, Dimitrios; Nanaki,; Pantopoulos,

    2011-01-01

    Stavroula G Nanaki1, Kostas Pantopoulos2, Dimitrios N Bikiaris11Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece; 2Lady Davis Institute for Medical Research and Department of Medicine, McGill University, Montreal, Quebec, CanadaAbstract: Poly(propylene adipate)-block-poly(ε-caprolactone) copolymers were synthesized using a combination of polycondensation and ring-opening polymerization of...

  8. Biodegradation of poly(lactic acid) and poly(butylene succinate-co-adipate) by Paenibacillus amylolyticus strain TB-13

    OpenAIRE

    Teeraphatpornchai, Teerawat

    2003-01-01

    Polymer materials developed during the last 80 years are generally resistant to microbial attack, a property that is now currently regarded as a shortcoming concerning solid waste management. As a source of alternative environmental friendly materials, the synthesis of degradable polymers is becoming of considerable interest.Recently, increasing iterest has been devoted to understanding the degradation mechanisms of polymers in the environment. A number of synthetic polymers have been referre...

  9. Production and characterization of novel starch and poly(butylene adipate-co-terephthalate)-based materials and their applications

    Science.gov (United States)

    Stagner, Jacqueline Ann

    This work focuses on the production and characterization of blends of maleated thermoplastic starch (MTPS) and poly(butylenes adipate-co-terephthalate) and their application for use as thermoformed objects, films, and foams. First, by the production and characterization of maleated thermoplastic starch (MTPS) synthesized by reactive extrusion in a twin-screw extruder, a better understanding of MTPS was gained. This reactive thermoplastic starch was prepared with glycerol as the plasticizer, maleic anhydride (MA), and free-radical initiator, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (Luperox 101). Dynamic light scattering (DLS), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), soxhlet extraction in acetone, and environmental scanning electron microscopy (ESEM) were performed to determine the effect of maleation, extrusion temperature, initiator concentration, and maleic anhydride concentration on the resulting MTPS. Next, maleated thermoplastic starch (MTPS) and thermoplastic starch (TPS) were reactively blended in a twin-screw extruder with a biodegradable polyester, poly(butylene adipate-co-terephthalate) (PBAT). The blends were extruded to produce thermoformable sheets. The mechanical properties of the sheets were characterized by tensile and puncture tests. Proof of grafting was determined by soxhlet extraction in dichloromethane and FTIR analysis. Observations of the thermal properties were made using DSC, while the surface of the sheets was imaged using ESEM. Blends of MTPS and PBAT were also extruded to produce films. Mechanical testing (tensile and puncture tests) and barrier performance testing (carbon dioxide, oxygen, and water vapor permeability) were performed on the films. Transmission electron microscopy (TEM) was used to image the blends and to view the dispersion of the various phases. Finally, blends of MTPS and PBAT were extruded with an endothermic chemical blowing agent to produce foams. The foams were

  10. Di-(2-ethylhexyl) adipate and 20 phthalates in composite food samples from the 2013 Canadian Total Diet Study.

    Science.gov (United States)

    Cao, Xu-Liang; Zhao, Wendy; Dabeka, Robert

    2015-01-01

    A sensitive and selective GC-MS method was developed and used for simultaneous analysis of di-(2-ethylhexyl) adipate (DEHA) and 20 selected phthalates in the food samples from the 2013 Canadian Total Diet Study. At least one of the 21 target chemicals was detected in 141 of the 159 different food composite samples analysed. However, only seven of the 21 target chemicals were detected, with di-(2-ethylhexyl) phthalate (DEHP) and DEHA being detected most frequently, in 111 and 91 different food composite samples, respectively, followed by di-n-butyl phthalate (DBP) (n = 44), n-butyl benzyl phthalate (BBzP) (32), di-iso-butyl phthalate (DiBP) (27), di-ethyl phthalate (DEP) (3), and di-cyclohexyl phthalate (DCHP) (1). Levels of DEP (di-ethyl phthalate), DiBP, DBP, BBzP and DCHP were low, in general, with average concentrations of 9.63, 8.26, 23.2, 12.4 and 64.9 ng g(-1), respectively. Levels of DEHA and DEHP varied widely, ranging from 1.4 to 6010 ng g(-1) and from 14.4 to 714 ng g(-1), respectively. High levels of DEHA were found mainly in the composite samples where the individual food items used to prepare the composite were likely packaged in polyvinyl chloride (PVC) wrapping film, while the highest DEHP levels were found in the vegetable and fruit samples.

  11. Preparation and characterization of crosslinked poly(butylene adipate-co-terephthalate)/polyhedral oligomeric silsesquioxane nanocomposite by electron beam irradiation

    International Nuclear Information System (INIS)

    The electron beam-induced crosslinking of poly(butylene adipate-co-terephthalate) (PBAT)/polyhedral oligomeric silsesquioxane (POSS) nanocomposites was investigated in this study. PBAT/POSS nanocomposites prepared by a solution blending with various compositions were crosslinked by electron beam irradiation at various absorbed doses ranging from 20 to 200 kGy and their properties were characterized in terms of their degree of crosslinking, morphology, thermal and mechanical properties, and biodegradability. The results of the degree of crosslinking measurements revealed that PBAT/POSS nanocomposites were more effectively crosslinked than the pure PBAT and that the degree of crosslinking was dependent on the absorbed dose and POSS content. From the results of the FE-SEM and EDX analyses, the POSS was found to be uniformly dispersed in the PBAT matrix. Based on the results of the UTM, DMA, and TMA, the crosslinked PBAT/POSS nanocomposites exhibited much higher thermal and mechanical properties compared to those of the pure PBAT. - Highlights: ► Crosslinked PBAT/POSS nanocomposites were prepared by electron beam irradiation. ► The POSS as a nanofillers was homogeneously dispersed in the PBAT matrix. ► The crosslinked nanocomposites exhibited improved thermal and mechanical properties.

  12. Effect of organo-modified montmorillonite on poly(butylene succinate/poly(butylene adipate-co-terephthalate nanocomposites

    Directory of Open Access Journals (Sweden)

    2010-07-01

    Full Text Available The composite material based on poly(butylene succinate (PBS, poly(butylene adipate-co-terephthalate (PBAT and organo-modified montmorillonite (OMMT were prepared by melt blending technique and characterized. Sodium montmorillonite (Na-MMT was successfully modified by octadecylammonium (ODA and dimethyldioctadecylammonium (DDOA salts to become OMMT through cation exchange technique which is shown by the increase of basal spacing of clay by XRD. The addition of the OMMT to the PBS/PBAT blends produced nanocomposites which is proved by XRD and TEM. Tensile tests showed increase in tensile strength and modulus which is attributed to the existence of strong interactions between PBS/PBAT and clay, particularly with OMMT. Highest tensile strength of nanocomposite was observed at 1 wt% of OMMT incorporated. TGA study showed that the thermal stability of the blend increased after the addition of clays. SEM micrographs of the fracture surfaces show that the morphology of the blend becomes homogeneous and smoother with presence of OMMT.

  13. Toughening of biodegradable polylactide/poly(butylene succinate-co-adipate) blends via in situ reactive compatibilization.

    Science.gov (United States)

    Ojijo, Vincent; Ray, Suprakas Sinha; Sadiku, Rotimi

    2013-05-22

    Polylactide and poly(butylene succinate-co-adipate) (PLA/PBSA) were melt-blended in the presence of triphenyl phosphite (TPP). An increase in the torque during melt mixing was used to monitor the changes in viscosity as compatibilization of the blends occurred. Scanning electron micrographs showed not only a reduction in the dispersed-phase size with increased TPP content but also fibrillated links between the PLA and PBSA phases, signifying compatibilization. Moreover, optimization of parameters such as the mixing sequence and time, TPP content, and PBSA concentration revealed that blends containing 30 and 10 wt % PBSA and 2 wt % TPP, which were processed for 30 min, were optimal in terms of thermomechanical properties. The impact strength increased from 6 kJ/m(2) for PLA to 11 and 16 kJ/m(2) for blends containing 30 and 10 wt % PBSA, respectively, whereas the elongation-at-break increased from 6% for PLA to 20 and 37% for blends containing 30 and 10 wt % PBSA, respectively. Upon compatibilization, the failure mode shifted from the brittle fracture of PLA to ductile deformation, effected by the debonding between the two phases. With improved phase adhesion, compatibilized blends not only were toughened but also did not significantly lose tensile strength and thermal stability.

  14. Morphology and mechanical properties of poly(butylene adipate-co-terephthalate)/potato starch blends in the presence of synthesized reactive compatibilizer or modified poly(butylene adipate-co-terephthalate).

    Science.gov (United States)

    Wei, Dafu; Wang, Hao; Xiao, Huining; Zheng, Anna; Yang, Yang

    2015-06-01

    The biodegradable poly(butylene adipate-co-terephthalate)(PBAT)/thermoplastic starch (TPS) composite has received considerable attention because of the environmental concerns raised by solid waste disposal. However, the application of PBAT/TPS blends was limited due to the poor mechanical properties originating from the incompatibility between PBAT and TPS. In this work, two approaches were developed to improve the mechanical properties of PBAT/TPS blends. One approach is to use compatibilizers, including the synthesized reactive compatibilizer - a styrene-maleic anhydride-glycidyl methacrylate (SMG) terpolymer, and the commercial compatibilizer (Joncryl-ADR-4368). The chemical structures of SMG were analyzed with (1)H NMR and FT-IR. The other approach is to use the modified PBAT (M-PBAT) to replace part of PBAT in the PBAT/TPS blends. M-PBATs with higher molecular weight were obtained via reactive extrusion of PBAT in the presence of a chain extender. The better dispersion of TPS in PBAT was observed in SEM images when using M-PBAT, leading to the higher tensile strength and elongation at break of PBAT/TPS blends. However, the elongation at break decreased in the presence of compatibilizer (SMG or 4368), though the tensile strength remained in a similar level or slightly higher. Overall, the tensile strength and the elongation at break of the resulting biodegradable PBAT/M-PBAT/TPS blends (TPS=40wt%) were above 27.0MPa and 500%, respectively, which is promising for various applications, including packaging and agricultural mulching films.

  15. THERMAL PROPERTY, MISCIBILITY AND CRYSTALLIZATION BEHAVIOR OF POLY(3-HYDROXYBUTYRATE-co 3-YDROXYHEXANOATE) AND POLY(BUTYLENE SUCCINATE-ADIPATE) (PHBHHX/PBSA) BLENDS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Blends of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(butylene succinate-adipate) (PBSA), both biodegradable semicrystalline polyesters, were prepared with the ratio of PHBHHx/PBSA ranging from 80/20 to 20/80 by melt mixing method. Differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), dynamic mechanical thermal analysis (DMA), polarizing optical microscopy (POM) and wide angle X-ray diffractometer (WAXD) were used to study the miscibility and crystallization behavior of PHBHHx/PBSA blends. Experimental results indicate that PHBHHx is immiscible with PBSA as shown by the almost unchanged glass transition temperature and the biphasic melt.

  16. The solubility measurements of sodium dicarboxylate salts; sodium oxalate, malonate, succinate, glutarate, and adipate in water from T = (279.15 to 358.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Rozaini, Mohd Zul Helmi [School of Environmental Science, University of East Anglia, Norwich, Norfolk NR4 7TJ (United Kingdom); Department of Chemical Sciences, Faculty of Science and Technology, University Malaysia Terengganu, 21030 Kuala Terengganu (Malaysia)], E-mail: zulhelmi@umt.edu.my; Brimblecombe, Peter [School of Environmental Science, University of East Anglia, Norwich, Norfolk NR4 7TJ (United Kingdom)

    2009-09-15

    The solubility measurements of sodium dicarboxylate salts; sodium oxalate, malonate, succinate, glutarate, and adipate in water at temperatures from (278.15 to 358.15 K) were determined. The molar enthalpies of solution at T = 298.15 K were derived: {delta}{sub sol}H{sub m} (m = 2.11 mol . kg{sup -1}) = 13.86 kJ . mol{sup -1} for sodium oxalate; {delta}{sub sol}H{sub m} (m = 3.99 mol . kg{sup -1}) = 14.83 kJ . mol{sup -1} for sodium malonate; {delta}{sub sol}H{sub m} (m = 2.45 mol . kg{sup -1}) = 14.83 kJ . mol{sup -1} for sodium succinate; {delta}{sub sol}H{sub m} (m = 4.53 mol . kg{sup -1}) = 16.55 kJ . mol{sup -1} for sodium glutarate, and {delta}{sub sol}H{sub m} (m = 3.52 mol . kg{sup -1}) = 15.70 kJ . mol{sup -1} for sodium adipate. The solubility value exhibits a prominent odd-even effect with respect to terms with odd number of sodium dicarboxylate carbon numbers showing much higher solubility. This odd-even effect may have implications for the relative abundance of these compounds in industrial applications and also in the atmospheric aerosols.

  17. Simultaneous analysis of phthalates, adipate and polycyclic aromatic hydrocarbons in edible oils using isotope dilution-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Oh, Min-Seok; Lee, Seon-Hwa; Moon, Myeong Hee; Lee, Dong Soo; Park, Hyun-Mee

    2014-01-01

    A method for simultaneous determination of 12 priority phthalates, adipate and polycyclic aromatic hydrocarbons (PAHs) in edible oils by isotope dilution-gas chromatography-mass spectrometry (ID-GC-MS) was developed for fast, accurate and trace analysis. The extraction and clean-up procedures were optimised, and using stable isotope-labelled internal standards for each analyte, relative standard deviations (RSDs) of 0.92-10.6% and spiked sample recoveries of 80.6-97.8% were obtained. Limits of detection for PAHs were in the range of 0.15-0.77 µg/kg and those for phthalates were in the range of 4.6-10.0 µg/kg. The calibration curves exhibited good linearities with regression coefficients of R(2) ≥ 0.99. Twelve edible oils were examined to evaluate the efficiency of this method. Among the 12 analytes, dibutyl phthalates (DBP), diethylhexyl phthalates (DEHP), diethylhexyl adipate (DEHA), benzo[a]anthracene (B[a]A), chrysene (Chry) and benzo[b]fluoranthene (B[b]F) were detected in the range of 1.17-806 µg/kg.

  18. Homogeneous vs. heterogeneous nucleation in water-dicarboxylic acid systems

    Directory of Open Access Journals (Sweden)

    A. I. Hienola

    2008-10-01

    Full Text Available Binary heterogeneous nucleation of water-succinic/glutaric/malonic/adipic acid on nanometer-sized particles is investigated within the frame of classical heterogeneous nucleation theory. Homogeneous nucleation is also included for comparison. It is found that the nucleation probabilities depend on the contact angle and on the size of the seed particles. New thermodynamical properties, such as saturation vapor pressure, density and surface tension for all the dicarboxylic acid aqueous solutions are included in the calculations. While the new surface tension and density formulations do not bring any significant difference in the computed nucleation rate for homogeneous nucleation for succinic and glutaric acids, the use of the newly derived equations for the vapor pressure decrease the acid concentrations in gas phase with 3 orders of magnitude. According to our calculations, the binary heterogeneous nucleation of succinic acid-water and glutaric acid-water – although it requires a 3–4 orders of magnitude lower vapor concentrations than the homogeneous nucleation – cannot take place in atmospheric conditions. On the other hand binary homogeneous nucleation of adipic acid-water systems might be possible in conditions occuring in upper boundary layer. However, a more detailed characterization of the interaction between the surface and the molecules of the nucleating vapor should be considered in the future.

  19. Preparation, Mechanical, and Thermal Properties of Biodegradable Polyesters/Poly(Lactic Acid Blends

    Directory of Open Access Journals (Sweden)

    Peng Zhao

    2010-01-01

    Full Text Available Series of biodegradable polyesters poly(butylene adipate (PBA, poly(butylene succinate (PBS, and poly(butylene adipate-co-butylene terephthalate (PBAT were synthesized successfully by melt polycondensation. The polyesters were characterized by Fourier transform infrared spectroscopy (FTIR, 1H-NMR, differential scanning calorimetry (DSC, and gel permeation chromatography (GPC, respectively. The blends of poly(lactic acid (PLA and biodegradable polyester were prepared using a twin screw extruder. PBAT, PBS, or PBA can be homogenously dispersed in PLA matrix at a low content (5–20 wt%, yielding the blends with much higher elongation at break than homo-PLA. DSC analysis shows that the isothermal and nonisothermal crystallizabilities of PLA component are promoted in the presence of a small amount of PBAT.

  20. Modelling the cloud condensation nucleus activity of organic acids

    Directory of Open Access Journals (Sweden)

    Z. Varga

    2007-04-01

    Full Text Available In this study vapour pressure osmometry was used to determine water activity in solutions of organic acids. The surface tension of the solutions was also monitored in parallel and then Köhler curves were calculated for nine organic acids (oxalic, malonic, succinic, glutaric, adipic acid, maleic acid, malic acid, citric acid and pinonic acid. Surface tension depression is negligible for most of the organic acids in dilute (≤1 w/w% solutions. Therefore, these compounds affect the supersaturation only in the beginning phase of droplet formation but not necessarily at the critical size. An exception is cis-pinonic acid which remarkably depress surface tension also in dilute (0.1 w/w% solution and hence at the critical point. The surface tension of organic acid solutions is influenced by the solubility of the compound, the length of the carbon chain and also by the polar functional groups present in the molecule. Similarly to surface tension solubility plays an important role also in water activity: compounds with higher solubility (e.g. malonic, maleic, and glutaric acid reduce water activity significantly in the early phase of droplet formation while less soluble acids (e.g. succinic and adipic acid are saturated in small droplets and the solution starts diluting only in bigger droplets. As a consequence, compounds with lower solubility have a minor effect on water activity in the early phase of droplet formation. To deduce the total effect Köhler curves were calculated and critical supersaturations were determined for the organic acids using measured surface tension and water activity. It was found that critical supersaturation grew with growing carbon number. Oxalic acid had the lowest critical supersaturation in the size range studied and it was comparable to the activation of ammonium sulfate. The Sc values obtained in this study were compared to data from CCNC measurements. In most cases good agreement was found.

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

    Science.gov (United States)

    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).

  2. Phase diagrams in blends of poly(3-hydroxybutyric acid with various aliphatic polyesters

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available Phase behavior with immiscibility, miscibility, crystalline morphology, and kinetic analysis in blends of poly(3-hydroxybutyric acid (PHB with aliphatic polyesters such as poly(butylene adipate (PBA, poly(ethylene adipate (PEA, poly(trimethylene adipate (PTA, or poly(ethylene succinate (PESu, respectively, were explored mainly using differential scanning calorimeter (DSC and polarized-light optical microscopy (POM. Immiscibility phase behavior with reversible upper-critical-solution-temperature (UCST is common in the PHB/polyester blends. The polyester/polyester blend of PHB/PTA is partially miscible with no UCST in melt and amorphous glassy states within a composition range of PTA less than 50 wt%. The miscible crystalline/crystalline blend exhibits ring-banded spherulites at Tc = 50~100°C, with inter-ring spacing dependent on Tc. All immiscible or partially miscible PHB/polyester blends, by contrast, exhibit disrupted ringbanded spherulites or discrete spherical phase domains upon cooling from UCST to crystallization. The blends of PHB with all other aliphatic polyesters, such as PESu, PEA, PBA, etc. are only partially miscible or immiscible with an upper critical solution temperature (UCST at 180~221°C depending on blend composition. UCST with reversibility was verified.

  3. Anthropometrische und psychosoziale Prädiktoren für den langfristigen Erfolg einer ambulanten Lifestyleintervention bei übergewichtigen und adipösen Kindern und Jugendlichen

    OpenAIRE

    Fröhlich, Georg

    2010-01-01

    Einleitung: Der Effektivitätsnachweis einer ambulanten Therapie von übergewichtigen und adipösen Kindern und Jugendlichen ist in der Vergangenheit mehrfach erbracht worden und weist zufriedenstellende Ergebnisse auf. Dennoch ist die Behandlung kontinuierlich zu verbessern. Diesbezüglich sind Teilnehmermerkmale, sog. Prädiktoren, zu eruieren, die den langfristigen Erfolg und die postinterventionelle BMI-SDS Entwicklung beschreiben. Methode: An der einjährigen ambulanten multimodalen Therapi...

  4. Water-enhanced solubility of carboxylic acids in organic solvents and its applications to extraction processes

    Energy Technology Data Exchange (ETDEWEB)

    Starr, J.N.; King, C.J.

    1991-11-01

    The solubilities of carboxylic acids in certain organic solvents increase remarkably with an increasing amount of water in the organic phase. This phenomenon leads to a novel extract regeneration process in which the co-extracted water is selectively removed from an extract, and the carboxylic acid precipitates. This approach is potentially advantageous compared to other regeneration processes because it removes a minor component of the extract in order to achieve a large recovery of acid from the extract. Carboxylic acids of interest include adipic acid, fumaric acid, and succinic acid because of their low to moderate solubilities in organic solvents. Solvents were screened for an increase in acid solubility with increased water concentration in the organic phase. Most Lewis-base solvents were found to exhibit this increased solubility phenomena. Solvents that have a carbonyl functional group showed a very large increase in acid solubility. 71 refs., 52 figs., 38 tabs.

  5. Synthesis and characterization of new optically active copoly(amid-imide)s based on N-phthalimido-L-aspartic acid and aromatic diamines

    Institute of Scientific and Technical Information of China (English)

    Khalil; Faghihi; Hamidreza; Alimohammadi

    2010-01-01

    In this article,six new optically active copoly(amide-imide)s(10a-f) were synthesized through the direct polycondensation reaction of N-phthalimido-L-aspartic acid(4) with 1,5-diamino naphthalene(8),3,4-diamino benzophenone(9) in the presence of therphthahc acid(7),fumaric acid(6) and adipic acid(5) as a second diacid in a medium consisting of N-methyl-2-pyrrolidone,triphenyl phosphite, calcium chloride and pyridine.The resulting copolymers were fully characterized by means of FT-IR spectroscopy,elementa...

  6. Investigation on Polylactide (PLA/Poly(butylene adipate-co-terephthalate (PBAT/Bark Flour of Plane Tree (PF Eco-Composites

    Directory of Open Access Journals (Sweden)

    Qiang Dou

    2016-05-01

    Full Text Available Polylactide (PLA/poly(butylene adipate-co-terephthalate (PBAT/bark flour of plane tree (PF eco-composites were prepared via melt blending. The morphologies, mechanical properties, crystal structures and melting and crystallization behaviors of the eco-composites were investigated by means of scanning electron microscopy (SEM, mechanical tests, polarized light microscopy (PLM, wide angle X-ray diffraction (WAXD and differential scanning calorimetry (DSC, respectively. It is shown that the interfacial adhesion between PLA matrix and PF is weak and the mechanical properties of PLA/PF eco-composites are poor. The titanate treatment improves the adhesion between the matrix and the filler and enhances the stiffness of the eco-composites. The toughness is improved by PBAT and ductile fractured surfaces can be found. The spherulitic size of PLA is decreased by the addition of PF. The α crystalline form of PLA remains in the composites. Compared with PF, T-PF (PF treated by a titanate coupling agent and PBAT have negative effects on the crystallization of PLA.

  7. Active biodegradable films produced with blends of rice flour and poly(butylene adipate co-terephthalate): effect of potassium sorbate on film characteristics.

    Science.gov (United States)

    Sousa, G M; Soares Júnior, M S; Yamashita, F

    2013-08-01

    The objective of work was to produce and characterize biodegradable films from rice flour, poly(butylene adipate co-terephthalate) (PBAT), glycerol and potassium sorbate, for application as active packaging for fresh lasagna pasta. The films were evaluated with respect to their optical, water vapor barrier, mechanical and microstructural properties. The mechanical properties and microstructure were evaluated after use as packaging material for fresh pasta for 45 days at 7°C. The blends of rice flour, PBAT, glycerol and potassium sorbate showed good processability and allowed for the pilot scale production of films by blow extrusion process. The addition of 1 to 5% potassium sorbate as plasticizer agent of films in place of glycerol did not alter the film mechanical properties and a sorbate concentration greater or equal than 3% reduced the opacity, although increasing the water vapor permeability. The films could be used as active packaging for fresh food pasta, since they remained integral and easy to handle after application. The rice flour was shown to be an excellent material for the formulation of biodegradable films, since it is a low-cost raw material from a renewable source. The addition of potassium sorbate did not affect the extrusion process, and could be used in the production of packaging for use with foods. PMID:23706195

  8. Effect of Chain-Extenders on the Properties and Hydrolytic Degradation Behavior of the Poly(lactide/ Poly(butylene adipate-co-terephthalate Blends

    Directory of Open Access Journals (Sweden)

    Mingqing Chen

    2013-10-01

    Full Text Available Biodegradable poly(lactide/poly(butylene adipate-co-terephthalate (PLA/PBAT blends were prepared by reactive blending in the presence of chain-extenders. Two chain-extenders with multi-epoxy groups were studied. The effect of chain-extenders on the morphology, mechanical properties, thermal behavior, and hydrolytic degradation of the blends was investigated. The compatibility between the PLA and PBAT was significantly improved by in situ formation of PLA-co-PBAT copolymers in the presence of the chain-extenders, results in an enhanced ductility of the blends, e.g., the elongation at break was increased to 500% without any decrease in the tensile strength. The differential scanning calorimeter (DSC results reveal that cold crystallization of PLA was enhanced due to heterogeneous nucleation effect of the in situ compatibilized PBAT domains. As known before, PLA is sensitive to hydrolysis and in the presence of PBAT and the chain-extenders, the hydrolytic degradation of the blend was evident. A three-stage hydrolysis mechanism for the system is proposed based on a study of weight loss and molecular weight reduction of the samples and the pH variation of the degradation medium.

  9. Effect of nanoclay loading on the thermal and mechanical properties of biodegradable polylactide/poly[(butylene succinate)-co-adipate] blend composites.

    Science.gov (United States)

    Ojijo, Vincent; Sinha Ray, Suprakas; Sadiku, Rotimi

    2012-05-01

    Polylactide/poly[(butylene succinate)-co-adipate] (PLA/PBSA)-organoclay composites were prepared via melt compounding in a batch mixer. The weight ratio of PLA to PBSA was kept at 70:30, while the weight fraction of the organoclay was varied from 0 to 9%. Small angle X-ray scattering patterns showed slightly better dispersion in PBSA than PLA, and there was a tendency of the silicate layers to delaminate in PBSA at low clay content. Thermal analysis revealed that crystallinity was dependent on the clay content as well its localization within the composite. On the other hand, thermal stability marginally improved for composites with 2 wt %. Tensile properties showed dependence on clay content and localization. Composite with 2 wt % clay content showed slight improvement in elongation at break. Overall, the optimum property was found for a composite with 2 wt % of the organoclay. This paper therefore has demonstrated the significance of the clay content and localization on the properties of the PLA/PBSA blends.

  10. Role of specific interfacial area in controlling properties of immiscible blends of biodegradable polylactide and poly[(butylene succinate)-co-adipate].

    Science.gov (United States)

    Ojijo, Vincent; Sinha Ray, Suprakas; Sadiku, Rotimi

    2012-12-01

    Binary blends of two biodegradable polymers: polylactide (PLA), which has high modulus and strength but is brittle, and poly[(butylene succinate)-co-adipate] (PBSA), which is flexible and tough, were prepared through batch melt mixing. The PLA/PBSA compositions were 100/0, 90/10, 70/30, 60/40, 50/50, 40/60, 30/70, 10/90, and 0/100. Fourier-transform infrared measurements revealed the absence of any chemical interaction between the two polymers, resulting in a phase-separated morphology as shown by scanning electron microscopy (SEM). SEM micrographs showed that PLA-rich blends had smaller droplet sizes when compared to the PBSA-rich blends, which got smaller with the reduction in PBSA content due to the differences in their melt viscosities. The interfacial area of PBSA droplets per unit volume of the blend reached a maximum in the 70PLA/30PBSA blend. Thermal stability and mechanical properties were not only affected by the composition of the blend, but also by the interfacial area between the two polymers. Through differential scanning calorimetry, it was shown that molten PBSA enhanced crystallization of PLA while the stiff PLA hindered cold crystallization of PBSA. Optimal synergies of properties between the two polymers were found in the 70PLA/30PBSA blend because of the maximum specific interfacial area of the PBSA droplets.

  11. Enhancement of Mechanical and Thermal Properties of Oil Palm Empty Fruit Bunch Fiber Poly(butylene adipate-co-terephtalate Biocomposites by Matrix Esterification Using Succinic Anhydride

    Directory of Open Access Journals (Sweden)

    Samira Siyamak

    2012-02-01

    Full Text Available In this work, the oil palm empty fruit bunch (EFB fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate PBAT (EcoflexTM, as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites’ performance by chemical modification using succinic anhydride (SAH as a coupling agent in the presence and absence of dicumyl peroxide (DCP and benzoyl peroxide (BPO as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt % and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA. Scanning Electron Microscopy (SEM was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt % of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt % succinic anhydride (SAH and 1 (wt % dicumyl peroxide (DCP improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites’ spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.

  12. Effect of fiber esterification on fundamental properties of oil palm empty fruit bunch fiber/poly(butylene adipate-co-terephthalate) biocomposites.

    Science.gov (United States)

    Siyamak, Samira; Ibrahim, Nor Azowa; Abdolmohammadi, Sanaz; Yunus, Wan Md Zin Wan; Rahman, Mohamad Zaki Ab

    2012-01-01

    A new class of biocomposites based on oil palm empty fruit bunch fiber and poly(butylene adipate-co-terephthalate) (PBAT), which is a biodegradable aliphatic aromatic co-polyester, were prepared using melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 wt% and characterized. Chemical treatment of oil palm empty fruit bunch (EFB) fiber was successfully done by grafting succinic anhydride (SAH) onto the EFB fiber surface, and the modified fibers were obtained in two levels of grafting (low and high weight percentage gain, WPG) after 5 and 6 h of grafting. The FTIR characterization showed evidence of successful fiber esterification. The results showed that 40 wt% of fiber loading improved the tensile properties of the biocomposite. The effects of EFB fiber chemical treatments and various organic initiators content on mechanical and thermal properties and water absorption of PBAT/EFB 60/40 wt% biocomposites were also examined. The SAH-g-EFB fiber at low WPG in presence of 1 wt% of dicumyl peroxide (DCP) initiator was found to significantly enhance the tensile and flexural properties as well as water resistance of biocomposite (up to 24%) compared with those of untreated fiber reinforced composites. The thermal behavior of the composites was evaluated from thermogravimetric analysis (TGA)/differential thermogravimetric (DTG) thermograms. It was observed that, the chemical treatment has marginally improved the biocomposites' thermal stability in presence of 1 wt% of dicumyl peroxide at the low WPG level of grafting. The improved fiber-matrix surface enhancement in the chemically treated biocomposite was confirmed by SEM analysis of the tensile fractured specimens. PMID:22408394

  13. Osteoconductive bio-based meshes based on Poly(hydroxybutyrate-co-hydroxyvalerate) and poly(butylene adipate-co-terephthalate) blends

    Energy Technology Data Exchange (ETDEWEB)

    Nar, Mangesh; Staufenberg, Gerrit; Yang, Bing [Department of Material Science and Engineering, University of North Texas, 1155 Union Circle #305310, Denton, TX 76203-5017 (United States); Robertson, Lesli [Department of Fibers, College of Visual Arts and Design, 1155 Union Circle #305100, Denton, TX 76203-5017 (United States); Patel, Rinkesh H. [Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A and M University Baylor College of Dentistry, Dallas, TX 75246 (United States); Varanasi, Venu G., E-mail: vvaranasi@bcd.tamhsc.edu [Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A and M University Baylor College of Dentistry, Dallas, TX 75246 (United States); D' Souza, Nandika Anne, E-mail: nandika.dsouza@unt.edu [Department of Material Science and Engineering, University of North Texas, 1155 Union Circle #305310, Denton, TX 76203-5017 (United States); Department of Mechanical and Energy Engineering, University of North Texas, 1155 Union Circle # 311098, Denton, TX 76203-5017 (United States)

    2014-05-01

    Poly(butylene adipate-co-terephthalate) (PBAT) and Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) are biopolymers that have the potential to be used in applications of bone healing. In this study, it is hypothesized that the polymer blend has the combined strength and osteoconductivity to support osteoblast collagen formation. PBAT (PBAT 100), and a blend with 20% PHBV (PBAT 80) were extruded in the form of fibers and then knitted in the form of mesh. These were tested in the warp as well as weft direction for the tensile properties; these showed that the weft direction had higher performance than the warp. The individual fibers were kept in phosphate buffered saline (PBS) over the period of 8 weeks and were tested for the storage and loss modulus using a dynamic mechanical analyser (DMA). The results indicated that mechanical relaxation strength showed a decrease and then an increase. In vitro osteoconductivity studies were done by using differentiating osteoblasts (MC3T3-E1 subclone 4 cells). Environmental Scanning Electron Microscopy (ESEM) showed that pre-soaking the samples in α-MEM for two weeks resulted in cell attachment and growth. X-ray diffraction (XRD) was used to determine the change in structure of polymers due to in vitro degradation for two weeks. Raman spectroscopy showed that all scaffolds supported the formation of a collagenous network over the scaffold surfaces. For a combination of knittable manufacturing, mechanical performance and osteoconductivity, blends offer an effective route. - Highlights: • PBAT and PHBV blend can be knitted to form mesh with good mechanical properties. • PBAT and PHBV blend do not show significant weight loss over a period of 8 weeks in PBS. • Osteoblast cell culture was done on these samples. • They support extracellular matrix and growth and hence are osteoconductive.

  14. Super-Robust Polylactide Barrier Films by Building Densely Oriented Lamellae Incorporated with Ductile in Situ Nanofibrils of Poly(butylene adipate-co-terephthalate).

    Science.gov (United States)

    Zhou, Sheng-Yang; Huang, Hua-Dong; Ji, Xu; Yan, Ding-Xiang; Zhong, Gan-Ji; Hsiao, Benjamin S; Li, Zhong-Ming

    2016-03-01

    Remarkable combination of excellent gas barrier performance, high strength, and toughness was realized in polylactide (PLA) composite films by constructing the supernetworks of oriented and pyknotic crystals with the assistance of ductile in situ nanofibrils of poly(butylene adipate-co-terephthalate) (PBAT). On the basis that the permeation of gas molecules through polymer materials with anisotropic structure would be more frustrated, we believe that oriented crystalline textures cooperating with inerratic amorphism can be favorable for the enhancement of gas barrier property. By taking full advantage of intensively elongational flow field, the dispersed phase of PBAT in situ forms into nanofibrils, and simultaneously sufficient row-nuclei for PLA are induced. After appropriate thermal treatment with the acceleration effect of PBAT on PLA crystallization, oriented lamellae of PLA tend to be more perfect in a preferential direction and constitute into a kind of network interconnecting with each other. At the same time, the molecular chains between lamellae tend to be more extended. This unique structure manifests superior ability in ameliorating the performance of PLA film. The oxygen permeability coefficient can be achieved as low as 2 × 10(-15) cm(3) cm cm(-2) s(-1) Pa(-1), combining with the high strength, modulus, and ductility (104.5 MPa, 3484 MPa, and 110.6%, respectively). The methodology proposed in this work presents an industrially scalable processing method to fabricate super-robust PLA barrier films. It would indeed push the usability of biopolymers forward, and certainly prompt wider application of biodegradable polymers in the fields of environmental protection such as food packaging, medical packaging, and biodegradable mulch. PMID:26959220

  15. Influence of low contents of superhydrophilic MWCNT on the properties and cell viability of electrospun poly (butylene adipate-co-terephthalate) fibers.

    Science.gov (United States)

    Rodrigues, Bruno V M; Silva, Aline S; Melo, Gabriela F S; Vasconscellos, Luana M R; Marciano, Fernanda R; Lobo, Anderson O

    2016-02-01

    The use of poly (butylene adipate-co-terephthalate) (PBAT) in tissue engineering, more specifically in bone regeneration, has been underexplored to date due to its poor mechanical resistance. In order to overcome this drawback, this investigation presents an approach into the preparation of electrospun nanocomposite fibers from PBAT and low contents of superhydrophilic multi-walled carbon nanotubes (sMWCNT) (0.1-0.5wt.%) as reinforcing agent. We employed a wide range of characterization techniques to evaluate the properties of the resulting electrospun nanocomposites, including Field Emission Scanning Electronic Microscopy (FE-SEM), Transmission Electronic Microscopy (TEM), tensile tests, contact angle measurements (CA) and biological assays. FE-SEM micrographs showed that while the addition of sMWCNT increased the presence of beads on the electrospun fibers' surfaces, the increase of the neat charge density due to their presence reduced the fibers' average diameter. The tensile test results pointed that sMWCNT acted as reinforcement in the PBAT electrospun matrix, enhancing its tensile strength (from 1.3 to 3.6MPa with addition of 0.5wt.% of sMWCNT) and leading to stiffer materials (lower elongation at break). An evaluation using MG63 cells revealed cell attachment into the biomaterials and that all samples were viable for biomedical applications, once no cytotoxic effect was observed. MG-63 cells osteogenic differentiation, measured by ALP activity, showed that mineralized nodules formation was increased in PBAT/0.5%CNTs when compared to control group (cells). This investigation demonstrated a feasible novel approach for producing electrospun nanocomposites from PBAT and sMWCNT with enhanced mechanical properties and adequate cell viability levels, which allows for a wide range of biomedical applications for these materials. PMID:26652433

  16. Effect of Fiber Esterification on Fundamental Properties of Oil Palm Empty Fruit Bunch Fiber/Poly(butylene adipate-co-terephthalate Biocomposites

    Directory of Open Access Journals (Sweden)

    Mohamad Zaki AB Rahman

    2012-01-01

    Full Text Available A new class of biocomposites based on oil palm empty fruit bunch fiber and poly(butylene adipate-co-terephthalate (PBAT, which is a biodegradable aliphatic aromatic co-polyester, were prepared using melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 wt% and characterized. Chemical treatment of oil palm empty fruit bunch (EFB fiber was successfully done by grafting succinic anhydride (SAH onto the EFB fiber surface, and the modified fibers were obtained in two levels of grafting (low and high weight percentage gain, WPG after 5 and 6 h of grafting. The FTIR characterization showed evidence of successful fiber esterification. The results showed that 40 wt% of fiber loading improved the tensile properties of the biocomposite. The effects of EFB fiber chemical treatments and various organic initiators content on mechanical and thermal properties and water absorption of PBAT/EFB 60/40 wt% biocomposites were also examined. The SAH-g-EFB fiber at low WPG in presence of 1 wt% of dicumyl peroxide (DCP initiator was found to significantly enhance the tensile and flexural properties as well as water resistance of biocomposite (up to 24% compared with those of untreated fiber reinforced composites. The thermal behavior of the composites was evaluated from thermogravimetric analysis (TGA/differential thermogravimetric (DTG thermograms. It was observed that, the chemical treatment has marginally improved the biocomposites’ thermal stability in presence of 1 wt% of dicumyl peroxide at the low WPG level of grafting. The improved fiber-matrix surface enhancement in the chemically treated biocomposite was confirmed by SEM analysis of the tensile fractured specimens.

  17. Enhancement of mechanical and thermal properties of oil palm empty fruit bunch fiber poly(butylene adipate-co-terephtalate) biocomposites by matrix esterification using succinic anhydride.

    Science.gov (United States)

    Siyamak, Samira; Ibrahim, Nor Azowa; Abdolmohammadi, Sanaz; Yunus, Wan Md Zin Bin Wan; Rahman, Mohamad Zaki Ab

    2012-01-01

    In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (Ecoflex™), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites' performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites' spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite. PMID:22343368

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

    Science.gov (United States)

    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.

  19. Optimisation of a wet FGD pilot plant using fine limestone and organic acids

    DEFF Research Database (Denmark)

    Frandsen, Jan; Kiil, Søren; Johnsson, Jan Erik

    2001-01-01

    The effects of adding an organic acid or using a limestone with a fine particle size distribution (PSD) have been examined in a wet flue gas desulphurisation (FGD) pilot plant. Optimisation of the plant with respect to the degree of desulphurisation and the residual limestone content of the gypsum...... has been the aim of the work. In contrast to earlier investigations with organic acids, all essential process parameters (i.e. gas phase concentration profiles of SO(2), slurry pH profiles. and residual limestone in the gypsum) were considered. Slurry concentrations of adipic acid in the range of 0......-7 mM were employed. The overall degree of desulphurisation in the plant increased from 83% at 0 mM to 90% at 3 mM and the residual limestone level was reduced from 4.6 to 1.4 wt%. Increasing the slurry concentration of adipic acid above 3 mM gave only a slightly higher degree of desulphurisation...

  20. Volatile aromatic hydrocarbons and dicarboxylic acid concentrations in air at an urban site in the Southwestern US

    Science.gov (United States)

    Tran, Ngoc K.; Steinberg, Spencer M.; Johnson, Brian J.

    Concentrations of benzene, toluene, ethylbenzene, o-xylene, and m- and p-xylene were measured at an urban sampling site in Las Vegas, NV by sorbent sampling followed by thermal desorption and determination by GC-PID. Simultaneously, measurements of oxalic, malonic, succinic, and adipic acids were made at the same site by collection on quartz filters, extraction, esterification, and determination by GC-FID. For the period from April 7, 1997 to June 11, 1997, 201 sets of hydrocarbon measurements and 99 sets of acid measurements were made. Additional measurements of dicarboxylic acids were made on samples that represented potential direct sources, e.g. green plants and road dust. Correlations between the hydrocarbon and CO concentrations (measured by the Clark County Health District at a nearby site) were highly significant and a strong negative correlation of hydrocarbon concentration with ozone concentration (also from the county site) was observed under quiescent atmospheric conditions. In general, dicarboxylic acid concentrations were well correlated with one another (with the exception of adipic acid) but not well correlated with hydrocarbon, CO, and ozone concentrations. Multiple sources and complex formation processes are indicated for the dicarboxylic acids.

  1. Preliminary Study on Lipase-catalyzed Synthesis of Polyesters Containing L-Malic Acid Units

    Institute of Scientific and Technical Information of China (English)

    Da Hu YAO; Guang Ji LI

    2006-01-01

    Terpolymer of 1, 8-octanediol, adipic acid, and L-malic acid was synthesized via a lipase-catalyzed direct polycondensation. The products were characterized by GPC and 1H NMR.The results indicated that the molecular weight of the prepared polymers decreased with increasing L-malic acid content in the monomer feed ratio, and that change in the L-malic acid content from 0to 20 mol % did not remarkably influenced on the molecular weight distribution Mw/Mn of the prepared samples. The 1H NMR spectra of the obtained copolymer samples showed that hydroxyl groups of L-malic acid did not take part in the polymerization reaction.

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

    Directory of Open Access Journals (Sweden)

    Heidi Adler

    2014-01-01

    Full Text Available 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.

  3. Teixit adipós epicàrdic i senyalització a través dels Receptors Toll like (TLR): Paper en la patofisiologia de l'aterosclerosi

    OpenAIRE

    Benaiges Martinez, Consol

    2015-01-01

    El Teixit adipós epicàrdic (TAE) és un dipòsit de greix visceral inusual amb continuïtat anatòmica i funcional amb les artèries coronàries i amb el miocardi. S’ha vist que en condicions fisiològiques el TAE mostra propietats cardioprotectores però en condicions patològiques el TAE pot afectar localment a les artèries coronàries a través de la secreció de substancies proinflamatòries i pot estar implicat en la patogènesi de l'aterosclerosi. L’objectiu d’aquest estudi es determinar el paper ...

  4. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    2012-01-01

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  5. Oxalic acid as a heterogeneous ice nucleus in the upper troposphere and its indirect aerosol effect

    Directory of Open Access Journals (Sweden)

    B. Zobrist

    2006-05-01

    Full Text Available Heterogeneous ice freezing points of aqueous solutions containing various immersed solid dicarboxylic acids (oxalic, adipic, succinic, phthalic and fumaric have been measured with a differential scanning calorimeter. The results show that only the dihydrate of oxalic acid (OAD acts as a heterogeneous ice nucleus, with an increase in freezing temperature between 2-5 K depending on solution composition. In several field campaigns, oxalic acid enriched particles have been detected in the upper troposphere with single particle aerosol mass spectrometry. Simulations with a microphysical box model indicate that the presence of OAD may reduce the ice particle number density in cirrus clouds by up to ~50% when compared to exclusively homogeneous cirrus formation without OAD. Using the ECHAM4 climate model we estimate the global net radiative effect caused by this heterogeneous freezing to result in a cooling as high as -0.3 Wm-2.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Estudi del canal de glicerol aqp7 i de l'adipoquina zag en l'àmbit de l'obesitat, la diabetis tipus 2 i la síndrome metabòlica. Dues proteïnes implicades en la lipòlisi del teixit adipós

    OpenAIRE

    Ceperuelo Mallafré, Mª Victòria

    2010-01-01

    L'obesitat incrementa les possibilitats de patir altres malalties com la diabetis mellitus tipus 2 (DM2), la dislipèmia, la hipertensió, entre d'altres. Per tal de poder avançar en noves dianes terapèutiques que millorin aquestes malalties és necessari conèixer millor la biologia del teixit adipós i els seus components. El teixit adipós blanc, a més a més d'emmagatzemar la major part de les reserves energètiques, és capaç de tenir activitat metabòlica i endocrina. Cal tenir en compte que un ...

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

    Science.gov (United States)

    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.

  10. Efeito de dietas hiperlipídicas com extrato de baru e chocolate sobre a área de adipócitos de ratos submetidos ao exercício físico

    Directory of Open Access Journals (Sweden)

    Fabricio Cesar de Paula Ravagnani

    2012-06-01

    Full Text Available INTRODUÇÃO: O acúmulo de tecido adiposo provoca uma série de distúrbios metabólicos, os quais poderiam ser atenuados pela modulação dietética e prática de exercícios físicos. OBJETIVO: Avaliar os efeitos de dietas hipercalóricas/hiperlipídicas com extrato de baru e chocolate associadas ao exercício aeróbio sobre a área de adipócitos e triglicérides hepáticos (TGLhep de ratos. MÉTODOS: Após o desmame, ratos da linhagem Wistar, com exceção dos controles (dieta Nuvilab®; 3,48kcal/g, foram alimentados com dieta à base de chocolate (4,17kcal/g, por dois meses, para indução da obesidade. Feito isso, os animais foram distribuídos em seis grupos: controle sedentários (CS, controle exercitados (CE, baru sedentários (BS, baru exercitados (BE, chocolate sedentários (CHOS, chocolate exercitados (CHOE, de acordo com a introdução da dieta com extrato de baru e treinamento de natação (2% do peso corporal., 8 sem., 5x/semana, 1h/sessão. Após a morte dos animais, o conteúdo de TGLhep foi determinado e os tecidos adiposos retroperitoneal, inguinal e omental foram removidos, pesados e submetidos à avaliação da área de adipócitos. RESULTADOS: As dietas hipercalóricas aumentaram o peso e a área de células do tecido retroperitoneal em relação à dieta controle (p BE: 0,88 ± 0,43mg.100mg-1; CHOS: 1,77 ± 0,64 > CHOE: 0,86 ± 0,41mg.100mg-1. CONCLUSÃO: O treinamento físico em intensidade leve à moderada reduziu significativamente os depósitos adiposos omental (visceral e inguinal dos animais alimentados com dieta controle e chocolate. Esse mesmo comportamento não foi reproduzido com a dieta à base de extrato de baru. Os animais exercitados apresentaram menor conteúdo de TGLhep, mesmo na persistência das dietas hiperlipídicas/hipercalóricas.

  11. Long-distance inter-hydrogen bond coupling effects in the polarized IR spectra of succinic acid crystals

    Science.gov (United States)

    Flakus, Henryk T.; Hachuła, Barbara; Hołaj-Krzak, Jakub T.

    2015-05-01

    The spectral properties of four different crystalline succinic acid (HOOC-(CH2)2-COOH) (SAC) isotopomer systems, h6, d2, d4 and d6, were examined by means of the IR spectroscopy in polarized light aided by numerical simulations of the νO-H and νO-D band contour shapes on utilizing the "strong-coupling" model. The abnormal IR spectral properties of SAC crystals in relation to the corresponding properties of glutaric, pimelic and adipic acid crystals were ascribed to the hyperconjugation electronic effects in the acid associated molecules. A vibronic coupling mechanism involving the proton stretching vibrations in the (COOH)2 cycles and the electronic motions in the molecular skeletons, the isotopic "H/D self-organization" mechanisms and a long-distance vibrational exciton coupling between the adjacent (COOH)2 cycles in the molecular chains are mainly responsible for the generation of the temperature effects in the crystalline IR spectra.

  12. Aqueous Phase Photo-Oxidation of Succinic Acid: Changes in Hygroscopic Properties and Reaction Products

    Science.gov (United States)

    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.

  13. Potentiometric studies on ternary complexes involving some divalent transition metal ions, gallic acid and biologically abundant aliphatic dicarboxylic acids in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Abdelatty Mohamed Radalla

    2015-06-01

    Full Text Available Formation of binary and ternary complexes of the divalent transition metal ions, Cu2+, Ni2+, Co2+ and Zn2+ with gallic acid and the biologically important aliphatic dicarboxylic acids (adipic, succinic, malic, malonic, maleic, tartaric and oxalic acids were investigated by means of the potentiometric technique at 25 °C and I = 0.10 mol dm−3 NaNO3. The acid-base properties of the ligands were investigated and discussed. The acidity constants of gallic acid and aliphatic dicarboxylic acids were determined and used for determining the stability constants of the binary and ternary complexes formed in the aqueous medium under the above experimental conditions. The formation of the different 1:1 and 1:2 binary complexes and 1:1:1 ternary complexes are inferred from the corresponding potentiometric pH-metric titration curves. The ternary complex formation was found to occur in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The values of Δ log K, percentage of relative stabilization (%R.S. and log X were evaluated and discussed. The concentration distribution of the various complex species formed in solution was evaluated and discussed. The mode of chelation of ternary complexes formed was ascertained by conductivity measurements.

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

    Directory of Open Access Journals (Sweden)

    Eva Vavříková

    2016-06-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  17. Oxidative degradation of organic acids conjugated with sulfite oxidation in flue-gas desulfurization. Final report, June 1984-June 1986

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.J.; Rochelle, G.T.

    1988-02-01

    This report gives results of a study of organic acid-degradation conjugated with sulfite oxidation under flue-gas desulfurization (FGD) conditions. The oxidative degradation constant, k12, is defined as the ratio of organic-acid degradation rate and sulfite oxidation-rate times the ratio of the concentrations of dissolved S(IV) and organic acid. It is not significantly affected by pH or dissolved oxygen in the absence of Mn or Fe. However, k12 is increased by certain transition metals such as Fe, Co, and Ni and is decreased by Mn and halides. Lower dissolved S(IV) magnifies these effects. A free-radical mechanism was proposed to describe the kinetics. 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), smaller dicarboxylic acids, monocarboxylic acids, other carbonyl compounds, and hydrocarbons.

  18. Oxidative degradation of organic acid conjugated with sulfite oxidation in flue gas desulfurization: products, kinetics and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.J.; Rochelle, G.T.

    1987-03-01

    Organic acid degradation conjugated with sulfite oxidation has been studied under flue gas desulfurization (FGD) conditions. The oxidative degradation constant k/sub 12/ is defined as the ratio of organic acid degradation rate and sulfite oxidation rate times the ratio of the concentration of dissolved S(IV) and organic acid. It is not significantly affected by pH or dissolved oxygen in the absence of manganese or iron. However, k/sub 12/ is increased by certain transition metals such as Fe, Co, and Ni and is decreased by Mn and halides. Lower dissolved S(IV) magnifies these effects. A free radical mechanism was proposed to describe the kinetics. Hydroxy and sulfonated carboxylic acids degrade approximately 3 times slower than saturated dicarboxylic acids, while maleic acid, an unsaturated dicarboxylic acid, degraded an order of magnitude factor. A wide spectrum of degradation products of adipic acid were found, including carbon dioxide - the major product - smaller dicarboxylic acids, monocarboxylic acids, other carbonyl compounds, and hydrocarbons. 30 references, 7 figures, 7 tables.

  19. 40 CFR 98.51 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an adipic acid production process and the...

  20. 76 FR 30781 - Confidentiality Determinations for Data Required Under the Mandatory Greenhouse Gas Reporting...

    Science.gov (United States)

    2011-05-26

    ... and units located in Indian Country. Adipic Acid Production....... 325199 Adipic acid manufacturing... business information. See 40 FR 21987, 21990 (May 20, 1975). \\2\\ GHGs Reported, Production/Throughput...); Subpart E, Adipic Acid Production (as amended by 75 FR 66434, October 28, 2010); Subpart F,...

  1. Synthesis and Crystal of Compound of 2-Aminopyrimidine and Adipic Acid%2—氨基嘧啶与己二酸化合物的合成和单晶培养

    Institute of Scientific and Technical Information of China (English)

    李伟; 郭玩桃

    2002-01-01

    2—氨基嘧啶与己二酸等摩尔混合,以一定比例的乙醇—水溶液为溶剂。在适当的物理化学条件下,合成未见报道的新型化合物,并培养出适合作。射线衍射实验研究的单晶。以供进一步作晶体结构研究。

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Modelling the cloud condensation nucleus activity of organic acids on the basis of surface tension and osmolality measurements

    Directory of Open Access Journals (Sweden)

    Z. Varga

    2007-09-01

    Full Text Available In this study vapour pressure osmometry was used to determine water activity in the solutions of organic acids. The surface tension of the solutions was also monitored in parallel and then Köhler curves were calculated for nine organic acids (oxalic, malonic, succinic, glutaric, adipic, maleic, malic, citric and cis-pinonic. Surface tension depression is negligible for most of the organic acids in dilute (≤1 w/w% solutions. Therefore, these compounds affect equilibrium vapour pressure only in the beginning phase of droplet formation when the droplet solution is more concentrated but not necessarily at the critical size. An exception is cis-pinonic acid which remarkably depress surface tension also in dilute (0.1 w/w% solution and hence at the critical point. The surface tension of organic acid solutions is influenced by the solubility of the compound, the length of the carbon chain and also by the polar functional groups present in the molecule. Similarly to surface tension solubility plays an important role also in water activity: compounds with higher solubility (e.g. malonic, maleic and glutaric acid reduce water activity significantly in the early phase of droplet formation while less soluble acids (e.g. succinic and adipic acid are saturated in small droplets and the solution starts diluting only in bigger droplets. As a consequence, compounds with lower solubility have a minor effect on water activity in the early phase of droplet formation. To deduce the total effect Köhler curves were calculated and critical supersaturations (Sc were determined for the organic acids using measured surface tension and water activity. It was found that critical supersaturation grew with growing carbon number. Oxalic acid had the lowest critical supersaturation in the size range studied and it was comparable to the activation of ammonium sulphate. The Sc values obtained in this study were compared to data from CCNC

  4. Controlled Release of Salicylic Acid from Biodegradable Cross-Linked Polyesters.

    Science.gov (United States)

    Dasgupta, Queeny; Chatterjee, Kaushik; Madras, Giridhar

    2015-09-01

    The purpose of this work was to develop a family of cross-linked poly(xylitol adipate salicylate)s with a wide range of tunable release properties for delivering pharmacologically active salicylic acid. The synthesis parameters and release conditions were varied to modulate polyester properties and to understand the mechanism of release. Varying release rates were obtained upon longer curing (35% in the noncured polymer to 10% in the cured polymer in 7 days). Differential salicylic acid loading led to the synthesis of polymers with variable cross-linking and the release could be tuned (100% release for the lowest loading to 30% in the highest loading). Controlled release was monitored by changing various factors, and the release profiles were dependent on the stoichiometric composition, pH, curing time, and presence of enzyme. The polymer released a combination of salicylic acid and disalicylic acid, and the released products were found to be nontoxic. Minimal hemolysis and platelet activation indicated good blood compatibility. These polymers qualify as "bioactive" and "resorbable" and can, therefore, find applications as immunomodulatory resorbable biomaterials with tunable release properties.

  5. Processing stability of cross-linked starches in acid sauce applications and identification of some of the molecular factors involved

    NARCIS (Netherlands)

    Steeneken, P.A.M.; Woortman, A.J.J.; Oudhuis, A.A.C.M.

    2011-01-01

    The thickening functionality of four acetylated di-starch adipates with variations in starch source and amylose and adipate contents was evaluated in a simplified small-scale model sauce system at fourteen processing conditions with variations in temperature, shear, and pH. A processing stability fa

  6. 己二酸/酚醛树脂共聚炭化制备多孔炭材料及其电性能研究%Preparation of Porous Carbon by Polymer Blending of Phenolic Resin and Adipic Diacid

    Institute of Scientific and Technical Information of China (English)

    夏笑虹; 刘洪波; 黄衍瑞; 杨丽; 石磊

    2011-01-01

    Porous carbons used for electric double layer capacitors (EDLCs) were prepared by chemical blending of phenolic resin (PF) and adipic diacid (DA). Chemical reaction of PF with diacid is manifested by a shift of carbonyl stretching peak of diacid to a higher frequency in FT-IR spectra and a higher decomposition temperature of diacid in TG curves. The influences of the ratio of vv(DA) to vv(PF) on pore structure, adsorption behavior and capacity performance were investigated. The specific surface area and total pore volume increase with the ratio of w(DA) to w(PF) at first and then decrease, reach the maximum at the value of w(PF)/w(DA), which are 550 cm2/g and 0.27 cm3/g, respectively. When the porous carbon used for the electrodes of electrochemical double layer capacitor (EDLC), a satisfied specific capacitances of 145 F/g in 30 wt% KOH aqueous electrolytes is acquired and the capacitance maintenance achieve 70% while the current density enlarged 50 times.%以酚醛树脂(PF)为炭前驱体,己二酸(DA)为致孔链段,利用聚合物共聚炭化法制备双电层电容器用多孔炭材料:通过红外和热重分析证实己二酸与酚醛树脂发生了化学反应,DA以链段或支链的形式存在于酚醛树脂固化体系中,并在后续炭化过程中热解逸出.氮气吸附分析表明酚醛树脂固化体系中的DA起到了一定的造孔作用,随着DA加入量增加,多孔炭比表面积先增大后减小,当w(PF)/w(DA )=3∶1时所得多孔炭的比表面积为550 cm2/g,孔容为0.27 cm3/g.采用直流充放电法、交流阻抗法和循环伏安法测定以上述多孔炭为电极材料的双电层电容器的电化学性能,结果表明:w(PF)/w(DA)=3:1时制得的多孔炭电极在30% KOH电解液中比电容为145 F/g,电流密度增大50倍,比电容保持率达到70%.

  7. Folic Acid

    Science.gov (United States)

    Folic acid is a B vitamin. It helps the body make healthy new cells. Everyone needs folic acid. For women who may get pregnant, it is really important. Getting enough folic acid before and during pregnancy can prevent major birth ...

  8. Amino acids

    Science.gov (United States)

    ... amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan , and valine. Nonessential amino acids "Nonessential" means that our bodies produce an amino ...

  9. Preparation and Characterization of Waterborne Polyurethaneurea Composed of Dimer Fatty Acid Polyester Polyol

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available A series of polyurethaneurea (PUU aqueous dispersions, which were stable at ambient temperature for more than 1 year, were prepared with C 36 -dimer-fatty-acid-based polyester polyol, isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine. The particle size of all these PUU (DPU aqueous dispersions ( <100 nm was less than that of comparable specimens, that is, poly-(neopentyl glycol adipate polyester-polyol-based PUU (APU aqueous dispersions, and the polydispersity index was very narrow ( ≤1.13 . The films prepared with the DPU aqueous dispersions exhibited excellent waterproof performance, such as low amount of water absorption (1.3 wt%, and good mechanical properties (hardness and tensile strength, resulting from the strong hydrogen bonding in urea carbonyl groups and the perfect ordered structure of hard segments compared with those prepared with the APU aqueous dispersions. The surface hydrophobicity of the films prepared with modified DPU aqueous dispersions, which were modified with a fluorinated polyacrylate emulsion, was excellent, as the water contact angle on the surface of such films rose up to 100. The mechanical properties of such modified DPU films were further enhanced.

  10. Joint effect of organic acids and inorganic salts on cloud droplet activation

    Directory of Open Access Journals (Sweden)

    M. Frosch

    2011-04-01

    Full Text Available We have investigated CCN properties of internally mixed particles composed of one organic acid (oxalic acid dihydrate, succinic acid, adipic acid, citric acid, cis-pinonic acid, or Nordic reference fulvic acid and one inorganic salt (sodium chloride or ammonium sulphate. Surface tension and water activity of aqueous model solutions with concentrations relevant for CCN activation were measured using a tensiometer and osmometry, respectively. The measurements were used to calculate Köhler curves and critical supersaturations, which were compared to measured critical supersaturations of particles with the same chemical compositions, determined with a cloud condensation nucleus counter. Surfactant surface partitioning was not accounted for. For the aqueous solutions containing cis-pinonic acid and fulvic acid, a depression of surface tension was observed, but for the remaining solutions the effect on surface tension was negligible at concentrations relevant for cloud droplet activation. The surface tension depression of aqueous solutions containing both organic acid and inorganic salt was approximately the same as or smaller than that of aqueous solutions containing the same mass of the corresponding pure organic acids. Water activity was found to be highly dependent on the type and amount of inorganic salt. Sodium chloride was able to decrease water activity more than ammonium sulphate and both inorganic salts are predicted to have a smaller Raoult term than the studied organic acids. Increasing the mass ratio of the inorganic salt led to a decrease in water activity. Water activity measurements were compared to results from the E-AIM model and values estimated from both constant and variable van't Hoff factors. The correspondence between measurements and estimates was overall good, except for highly concentrated solutions. Critical supersaturations calculated with Köhler theory based on measured water activity and surface tension, but not

  11. 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

    Science.gov (United States)

    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.

  12. Folic Acid

    Science.gov (United States)

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

  13. 胃旁路术对2型糖尿病大鼠脂肪组织胰岛素受体β及胰岛素受体底物-1表达的影响%Effect of gastric bypass operation on expressions of adipic insulin receptor and insulin receptor substrate-1 in rats with type 2 diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    徐键; 林杉; 尹家俊

    2015-01-01

    Objective To investigate the expressions of adipic insulin receptor β (IR-β) and insulin receptor substrate-1 (IRS-1) after gastric bypass (GBP) operation in spontaneous rats with type 2 diabetes mellitus (GK rats) and to elucidate the mechanisms of GBP in improving insulin resistance. Methods Thirty male GK rats aged 8 weeks were randomly divided into 3 groups according to the table of random number:the operation group (GBP, 10 rats), the sham operation group (the same sites were cut off as GBP and end to end anastomosis was performed in site, 10 rats) and the diet pairing group (the same kind and weight dieting as the operation group, 10 rats), besides 10 male SD rats aged 8 weeks were used as blank control group (free eating and drinking). Four weeks before and after operation, levels of fasting blood glucose (FPG) and fasting insulin (FINS) were measured, HOMA-IR was calculated respectively, and compared among 4 groups. Then rats were decapitated to retrieve the omentum. Expressions of adipic IR-βand IRS-1 protein were detected by Western blot. Results Compared with the preoperative levels, the FPG and HOMA-IR decreased significantly 4 weeks after surgery in operation group [(5.13±0.22) vs. (11.73±0.37) mmol/L, 2.16± 0.18 vs. 5.10±0.29, P0.05). FINS showed no obvious change in these 4 groups after operation(all P>0.05). Expressions of IR-β and IRS-1 were significantly higher in operation group than those in other 3 groups 4 weeks after the operation (all P0.05);而假手术组和饮食配对组较术前无显著变化(均P>0.05);术后4周手术组IR-β及IRS-1表达量均明显高于其他3组(均P<0.05)。结论胃旁路术能上调2型糖尿病大鼠胰岛素信号转导通路中IR-β及IRS-1的表达,改善脂肪组织胰岛素抵抗,提高胰岛素的敏感性。

  14. Joint effect of organic acids and inorganic salts on cloud droplet activation

    Directory of Open Access Journals (Sweden)

    M. Frosch

    2010-07-01

    Full Text Available We have investigated CCN properties of internally mixed particles composed of one organic acid (oxalic acid, succinic acid, adipic acid, citric acid, cis-pinonic acid, or nordic reference fulvic acid and one inorganic salt (sodium chloride or ammonium sulphate. Surface tension and water activity of aqueous model solutions with concentrations relevant for CCN activation were measured using a tensiometer and osmometry, respectively. The measurements were used to calculate Köhler curves, which were compared to measured critical supersaturations of particles with the same chemical compositions, determined with a cloud condensation nucleus counter. Surfactant surface partitioning was not accounted for. For the mixtures containing cis-pinonic acid or fulvic acid, a depression of surface tension was observed, but for the remaining mixtures the effect on surface tension was negligle at concentrations relevant for cloud droplet activation, and water activity was the more significant term in the Köhler equation. The surface tension depression of aqueous solutions containing both organic acid and inorganic salt was approximately the same as or smaller than that of aqueous solutions containing the same mass of the corresponding pure organic acids. Water activity was found to be highly dependent on the type and amount of inorganic salt. Sodium chloride was able to decrease water activity more than ammonium sulphate and both inorganic compounds had a higher effect on water activity than the studied organic acids, and increasing the mass ratio of the inorganic compound led to a decrease in water activity. Water activity measurements were compared to results from the E-AIM model and values estimated from both constant and variable van't Hoff factors to evaluate the performance of these approaches. The correspondence between measuments and estimates was overall good, except for highly concentrated solutions. Critical supersaturations calculated with K

  15. Ibotenic acid and thioibotenic acid

    DEFF Research Database (Denmark)

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

    2004-01-01

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

  16. Biopolymer Blends Based on Poly (lactic acid: Shear and Elongation Rheology/Structure/Blowing Process Relationships

    Directory of Open Access Journals (Sweden)

    Racha Al-Itry

    2015-05-01

    Full Text Available This study was dedicated to the blown film extrusion of poly(lactic acid, which mainly presents poor shear and elongation viscosities, and its blends. In order to enhance its melt strength, two main routes were selected (i a structural modification through chain extension and branching mechanisms by adding a reactive multifunctional epoxide (named Joncryl and (ii blending with poly(butylene adipate-co-terephtalate, named PBAT in presence (or not of Joncryl. The effects of the reactive agent on the shear and elongation rheology, morphological, and interfacial properties of the blends were systematically investigated. A decrease of the interfacial tension has been also demonstrated according to the deformed drop retraction method (DDRM. Hence, the role of Joncryl as a compatibilizer was highlighted. Consequently, finer morphology of the dispersed phase was obtained. Furthermore, the impact of the two modification routes on the blown film extrusion ability of PLA has been studied. Based on the improved shear and elongational rheological properties, a great enlargement of the blowing processing window of PLA modified with Joncryl was demonstrated. Indeed, with the addition of Joncryl into PLA–PBAT blends, a reduction of the instability defects has been detected. Finally, the induced crystalline structure and the thermo-mechanical properties of blown films were shown to be improved.

  17. [Gastric Acid].

    Science.gov (United States)

    Ruíz Chávez, R

    1996-01-01

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

  18. Validação em laboratório de método analítico para determinação do teor de adipato e ftalato de di-(2-etil-hexila utilizados como plastificantes em filmes flexíveis de PVC Validation in laboratory of the analytical method to determine di-(2-ethylhexyl phthalate and adipate utilized as plasticizers in pvc films

    Directory of Open Access Journals (Sweden)

    Andreia Artur Esteves

    2007-02-01

    Full Text Available The validation of analytical methods was carried out for di-(ethylhexyl phthalate (DEHP and adipate (DEHA the determination of in PVC films. The level of DEHP and DEHA in samples was determined by leaving the film in contact with n-heptane during 48 hours and analysis in a gas chromatograph (GC equipped with a flame ionization detector and fused silica column with 5% phenylmethyl silicone in the dimensions 30 m x 0.53 mm x 2.65 mm. The results for detection and the quantification limits were smaller than the restriction limits. The recovery rates of DEHP and DEHA were, respectively, 69.10 and 75.30 %.

  19. Organosulfates and organic acids in Arctic aerosols: speciation, annual variation and concentration levels

    Science.gov (United States)

    Hansen, A. M. K.; Kristensen, K.; Nguyen, Q. T.; Zare, A.; Cozzi, F.; Nøjgaard, J. K.; Skov, H.; Brandt, J.; Christensen, J. H.; Ström, J.; Tunved, P.; Krejci, R.; Glasius, M.

    2014-02-01

    Sources, composition and occurrence of secondary organic aerosols (SOA) in the Arctic were investigated at Zeppelin Mountain, Svalbard, and Station Nord, northeast Greenland, during the full annual cycle of 2008 and 2010 respectively. We focused on the speciation of three types of SOA tracers: organic acids, organosulfates and nitrooxy organosulfates from both anthropogenic and biogenic precursors, here presenting organosulfate concentrations and compositions during a full annual cycle and chemical speciation of organosulfates in Arctic aerosols for the first time. Aerosol samples were analysed using High Performance Liquid Chromatography coupled to a quadrupole Time-of-Flight mass spectrometer (HPLC-q-TOF-MS). A total of 11 organic acids (terpenylic acid, benzoic acid, phthalic acid, pinic acid, suberic acid, azelaic acid, adipic acid, pimelic acid, pinonic acid, diaterpenylic acid acetate (DTAA) and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA)), 12 organosulfates and one nitrooxy organosulfate were identified at the two sites. Six out of the 12 organosulfates are reported for the first time. Concentrations of organosulfates follow a distinct annual pattern at Station Nord, where high concentration were observed in late winter and early spring, with a mean total concentration of 47 (±14) ng m-3, accounting for 7 (±2)% of total organic matter, contrary to a considerably lower organosulfate mean concentration of 2 (±3) ng m-3 (accounting for 1 (±1)% of total organic matter) observed during the rest of the year. The organic acids followed the same temporal trend as the organosulfates at Station Nord; however the variations in organic acid concentrations were less pronounced, with a total mean organic acid concentration of 11.5 (±4) ng m-3 (accounting for 1.7 (±0.6)% of total organic matter) in late winter and early spring, and 2.2 (±1) ng m-3 (accounting for 0.9 (±0.4)% of total organic matter) during the rest of the year. At Zeppelin Mountain

  20. Organosulfates and organic acids in Arctic aerosols: speciation, annual variation and concentration levels

    Directory of Open Access Journals (Sweden)

    A. M. K. Hansen

    2014-02-01

    Full Text Available Sources, composition and occurrence of secondary organic aerosols (SOA in the Arctic were investigated at Zeppelin Mountain, Svalbard, and Station Nord, northeast Greenland, during the full annual cycle of 2008 and 2010 respectively. We focused on the speciation of three types of SOA tracers: organic acids, organosulfates and nitrooxy organosulfates from both anthropogenic and biogenic precursors, here presenting organosulfate concentrations and compositions during a full annual cycle and chemical speciation of organosulfates in Arctic aerosols for the first time. Aerosol samples were analysed using High Performance Liquid Chromatography coupled to a quadrupole Time-of-Flight mass spectrometer (HPLC-q-TOF-MS. A total of 11 organic acids (terpenylic acid, benzoic acid, phthalic acid, pinic acid, suberic acid, azelaic acid, adipic acid, pimelic acid, pinonic acid, diaterpenylic acid acetate (DTAA and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA, 12 organosulfates and one nitrooxy organosulfate were identified at the two sites. Six out of the 12 organosulfates are reported for the first time. Concentrations of organosulfates follow a distinct annual pattern at Station Nord, where high concentration were observed in late winter and early spring, with a mean total concentration of 47 (±14 ng m−3, accounting for 7 (±2% of total organic matter, contrary to a considerably lower organosulfate mean concentration of 2 (±3 ng m−3 (accounting for 1 (±1% of total organic matter observed during the rest of the year. The organic acids followed the same temporal trend as the organosulfates at Station Nord; however the variations in organic acid concentrations were less pronounced, with a total mean organic acid concentration of 11.5 (±4 ng m−3 (accounting for 1.7 (±0.6% of total organic matter in late winter and early spring, and 2.2 (±1 ng m−3 (accounting for 0.9 (±0.4% of total organic matter during the rest of the year. At Zeppelin Mountain

  1. Stearic Acid

    Science.gov (United States)

    Young, Jay A.

    2004-01-01

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

  2. Perfluorooctanoic acid

    NARCIS (Netherlands)

    P. de Voogt

    2014-01-01

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

  3. Solder Flux Residues and Humidity-Related Failures in Electronics: Relative Effects of Weak Organic Acids Used in No-Clean Flux Systems

    Science.gov (United States)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-04-01

    This paper presents the results of humidity testing of weak organic acids (WOAs), namely adipic, succinic, glutaric, dl-malic, and palmitic acids, which are commonly used as activators in no-clean solder fluxes. The study was performed under humidity conditions varying from 60% relative humidity (RH) to ˜99%RH at 25°C. The following parameters were used for characterization of WOAs: mass gain due to water adsorption and deliquescence of the WOA (by quartz crystal microbalance), resistivity of the water layer formed on the printed circuit board (by impedance spectroscopy), and leakage current measured using the surface insulation resistance pattern in the potential range from 0 V to 10 V. The combined results indicate the importance of the WOA chemical structure for the water adsorption and therefore conductive water layer formation on the printed circuit board assembly (PCBA). A substantial increase of leakage currents and probability of electrochemical migration was observed at humidity levels above the RH corresponding to the deliquescence point of WOAs present as contaminants on the printed circuit boards. The results suggest that use of solder fluxes with WOAs having higher deliquescence point could improve the reliability of electronics operating under circumstances in which exposure to high humidity is likely to occur.

  4. Analysis of phthalic acid diesters, monoester, and other plasticizers in polyvinyl chloride household products in Japan.

    Science.gov (United States)

    Kawakami, Tsuyoshi; Isama, Kazuo; Matsuoka, Atsuko

    2011-01-01

    The aim of this study was to determine the concentrations of six phthalic acid diesters (PAEs) [di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), diisononyl phthalate (DINP), di-n-octyl phthalate (DNOP), and diisodecyl phthalate (DIDP)], two non-phthalic plasticizers [di(2-ethylhexyl) adipate (DEHA), 2,2,4-trimethyl-1,3-pentanediol diisobutylate (TMPDIB)], and mono 2-ethylhexyl phthalate(MEHP) in polyvinyl chloride (PVC) household products that children often places in their mouths and/or contact with their skin (41 products, 47 samples) in Japan. The detection frequencies of the studied compounds were as follows: DEHP (79 %), DINP-2 (13 %), DINP-1 (11 %), DBP (8.5 %), DEHA (8.5 %), DIDP (4.3 %), and DNOP (2.1 %). Concentrations of these compounds ranged from 0.021 % to 48 %. BBP and TMPDIB were not detected in the all samples. Most samples contained DEHP and DINP at high concentrations over 0.1 %. High concentrations of PAEs were detected in PVC household products that appear appealing to children and can possibly be licked and chewed by them. Di(2-ethylhexyl) terephtalete, diisononyl 1,2-cyclohexanedicarboxylic acid, acetyl tributyl citrate, and di(2-ethylhexyl) 4-cyclohexene-1,2-dicarboxylate used as substitute plasticizers were also detected in several samples. MEHP was present in 70 % of the samples, with concentrations ranging from trace amounts to 140 μg/g. The ratios of MEHP against DEHP were 6.2 × 10(-4) to 1.6 × 10(-1) %. MEHP in the household products investigated in this study was most probably an impurity in DEHP. The high concentrations of PAEs detected in products that children often place in their mouth reveal the importance of replacing plasticizers in common household products, and not just children's toys, with safer alternatives.

  5. Modification of poly (butylene succinate-co-butylene adipate) (PBSA) by physical blending with poly (1,2-propylene succiate) (PPSu)%聚(丁二酸-1,2-丙二酯)(PPSu)对聚(丁二酸丁二酯-共聚-己二酸丁二酯)(PBSA)的物理改性的研究

    Institute of Scientific and Technical Information of China (English)

    王瑞冬; 徐军; 郭宝华

    2012-01-01

    聚(丁二酸丁二酯-共聚-己二酸丁二酯)(PBSA)是一种全生物降解材料,但由于其结晶度较高,无定形区比例较少,导致韧性不足.聚(丁二酸-1,2-丙二酯)(PPSu)是一种非结晶的生物可降解聚酯,在室温下处于无定型态.研究了PPSu对于PBSA的物理改性作用,通过DSC、DMA、POM、SEM测试对PBSA/PPSu的共混体系进行了表征,发现这2种脂肪族聚酯的共混物为部分相容体系,少量PPSu和PBSA相容.随PPSu质量分数的增加,共混体系玻璃化转变温度稍有升高,结晶速率下降.PPSu质量分数达10%时,断面刻蚀的SEM图片显示相分离结构.力学性能测试结果表明,在混入少量PPSu后,PBSA的抗冲击强度得到了较大提升.%Poly (butylene succinate-co-butylene adipate) (PBSA) is a kind of biodegradable material. However, due to its high degree of crystallinity and a low proportion of amorphou region,PBSA has low impact resistance. Poly( 1, 2-propylene succiate) (PPSu) is a kind of amorphous polymer,which can also be fully degraded in environment. In this study, PPSu is blended with PBSA. The miscibility, crystallization kinetics and the mechanical properties of the blends are investigated. Differential scanning caloreroetry, thermomechanical analysis, phase contrast optical microscopy and scanning electron microscopy have been adopted to study the miscibility of the two polymer components. The results show that PBSA and PPSu are miscible partially. When PPSu content is larger than 10 wt% , phase separation is observed in the blends. Increasing the amount of PPSu,the blends have higher glass transition temperature and slower crystallization rate. Compared with PBSA,the impact strength of the blends is greatly improved.

  6. Hydroxycarboxylic acids and salts

    Energy Technology Data Exchange (ETDEWEB)

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  7. Hydrofluoric acid poisoning

    Science.gov (United States)

    Fluorhydric acid ... stomach, or intestine have holes (perforations) from the acid. ... Hydrofluoric acid is especially dangerous. The most common accidents involving hydrofluoric acid cause severe burns on the skin ...

  8. Understanding Acid Rain

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  9. Okadaic acid

    DEFF Research Database (Denmark)

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

    2014-01-01

    was studied at the electron microscopic level using the membrane-impermeable marker Ruthenium Red (RR). Like FM dye, RR was taken up into TWEEs and multivesicular bodies (MVBs). However, OA induced the formation of a large number of lamellar bodies (LBs), a type of lysosome-related organelles. LBs...... hyper protein phosphorylation, but no detectable loss of cell polarity or cytoskeletal integrity of the enterocytes. Using a fluorescent membrane marker, FM dye, endocytosis from the brush border was affected by the toxin. Although constitutive uptake into subapical terminal web-localized early...... in acidic organelles, implying a different toxic mechanism of action. We propose that rapid induction of LBs, an indicator of phospholipidosis, should be included in the future toxicity profile of OA....

  10. Dehydroabietic acid

    Directory of Open Access Journals (Sweden)

    Xiao-Ping Rao

    2009-10-01

    Full Text Available The title compound [systematic name: (1R,4aS,10aR-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds.

  11. Corrosion inhibition of carbon steel by sodium metavanadate

    Directory of Open Access Journals (Sweden)

    VIJAYA GOPAL SRIBHARATHY

    2012-08-01

    Full Text Available The inhibition efficiency of sodium metavanadate (SMV-adipic acid (AA system in controlling corrosion of carbon steel in an aqueous solution containing 60 ppm of Cl- has been evaluated by weight-loss method; 250 ppm of SMV exhibits inhibition efficiency of 56 %. Addition of adipic acid to SMV improves the inhibition efficiency of the system. The formulation consisting of 250 ppm of SMV and 250 ppm of adipic acid has inhibition efficiency of 98 %. A synergistic effect exists between SMV and adipic acid with the synergism parameters greater than 1. Mecha¬nistic aspects of corrosion inhibition have been studied by electrochemical methods like potentiodynamic polarization and electrochemical impedance spectroscopy. FTIR spectra reveal that the protective film consists of Fe2+-SMV complex and Fe2+-adipic acid complex. The protective film has been analyzed by fluorescence spectra, SEM and EDAX.

  12. Seasonal characteristics of oxalic acid and related SOA in the free troposphere of Mt. Hua, central China: implications for sources and formation mechanisms.

    Science.gov (United States)

    Meng, Jingjing; Wang, Gehui; Li, Jianjun; Cheng, Chunlei; Ren, Yanqin; Huang, Yao; Cheng, Yuting; Cao, Junji; Zhang, Ting

    2014-09-15

    PM10 aerosols from the summit of Mt. Hua (2060 m a.s.l) in central China during the winter and summer of 2009 were analyzed for dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls. Molecular composition of dicarboxylic acids (C2-C11) in the free tropospheric aerosols reveals that oxalic acid (C2, 399 ± 261 ng m(-3) in winter and 522 ± 261 ng m(-3) in summer) is the most abundant species in both seasons, followed by malonic (C3) and succinic (C4) acids, being consistent with that on ground levels. Most of the diacids are more abundant in summer than in winter, but adipic (C6) and phthalic (Ph) acids are twice lower in summer, suggesting more significant impact of anthropogenic pollution on the wintertime alpine atmosphere. Moreover, glyoxal (Gly) and methylglyoxal (mGly) are also lower in summer (12 ± 6.1 ng m(-3)) than in winter (22 ± 13 ng m(-3)). As both dicarbonyls are a major precursor of C2, their seasonal variation patterns, which are opposite to those of the diacids, indicate that the mountain troposphere is more oxidative in summer. C2 showed strong linear correlations with levoglucosan in winter and oxidation products of isoprene and monoterpene in summer. PCA analysis further suggested that the wintertime C2 and related SOA in the Mt. Hua troposphere mostly originate from photochemical oxidations of anthropogenic pollutants emitted from biofuel and coal combustion in lowland regions. On contrast, the summertime C2 and related SOA mostly originate from further oxidation of the mountainous isoprene and monoterpene oxidation products. The AIM model calculation results showed that oxalic acid concentration well correlated with particle acidity (R(2)=0.60) but not correlated with particle liquid water content, indicating that particle acidity favors the organic acid formation because aqueous-phase C2 production is the primary mechanism of C2 formation in ambient aerosols and is driven by acid-catalyzed oxidation. PMID:24925591

  13. Effects of total gastrectomy on plasma silicon and amino acid concentrations in men.

    Science.gov (United States)

    Tatara, Marcin R; Krupski, Witold; Szpetnar, Maria; Dąbrowski, Andrzej; Bury, Paweł; Szabelska, Anna; Charuta, Anna; Boguszewska-Czubara, Anna; Maciejewski, Ryszard; Wallner, Grzegorz

    2015-12-01

    The aim of the study was to determine one-year effects of total gastrectomy on plasma silicon and free amino acid concentrations in patients and evaluate changes of volumetric bone mineral density (vBMD) in lumbar spine. Eight patients were enrolled to the control (CTR) group. Six patients subjected to total gastrectomy (GX group) were included to the experimental group. vBMD in trabecular and cortical bone was measured in lumbar vertebrae at baseline (before surgery) and one year later using quantitative computed tomography. Plasma concentrations of silicon and free amino acids were determined at baseline and one year later using photometric method and ion-exchange chromatography. Body weights within CTR and GX groups were not different after one-year follow-up when compared to the baseline values (P > 0.05). An average annual decrease of vBMD in the trabecular bone in the gastrectomized patients reached 15.0% in lumbar spine and was significantly different in comparison to the percentage changes observed in CTR group (P = 0.02). One-year percentage change of vBMD in the cortical bone in L1 and L2 has shown significantly decreased values by 10.5 and 9.1% in the GX group when compared to the percentage change observed in the controls (P < 0.05). Plasma concentration of adipic acid was significantly higher by 101.6% one year after total gastrectomy procedure in the patients when compared to the baseline value (P = 0.01). Plasma concentration of silicon was significantly lowered by 26.7% one year after the total gastrectomy when compared to the baseline value (P = 0.009). Total gastrectomy in patients has induced severe osteoporotic changes in lumbar spine within one-year period. The observed osteoporotic changes were associated with decreased plasma concentration of silicon indicating importance of exocrine and endocrine functions of stomach for silicon homeostasis maintenance. Gastrectomy-induced bone loss was not related to decreased amino acid

  14. Hidrofilicidade de filmes de amido/poli(butileno adipato co-tereftalato (Pbat adicionados de tween 80 e óleo de soja Hydrophilicity of starch and poly(butylene adipate-co-terephthalate (Pbat films containing tween 80 and soybean oil

    Directory of Open Access Journals (Sweden)

    Renata P. Herrera Brandelero

    2013-01-01

    Full Text Available A incorporação de amido ao polímero poli (butilenoadipatoco-tereftalato (PBAT através de blendas com alto teor de amido pode ser uma alternativa para obter embalagens biodegradáveis, minimizar custos e o uso de recursos não renováveis. No entanto, a adição de amido aumenta a permeabilidade ao vapor de água (PVA. A incorporação em filmes com amido de substâncias como óleos vegetais e surfactantes pode diminuir a hidrofilicidade, favorecendo as aplicações destes como embalagens. A hidrofilicidade dos filmes elaborados por blendas de amido/PBAT adicionados de óleo de soja (OS e tween 80 (TW foi avaliada considerando o efeito do OS e TW nas isotermas de sorção dos filmes, na PVA e nos coeficientes de difusão (Dw e solubilidade (β do vapor de água. Filmes com OS com ou sem TW apresentaram menor quantidade de água de sorção, sendo os filmes com menores quantidades de OS e sem TW menos hidrofílicos e menos permeáveis aos vapores de água. A adição de OS reduziu os valores de β e Dw dos filmes de amido/PBAT. O efeito foi relacionado com o aumento das porções hidrofóbicas e da compatibilidade entre o amido e PBAT na presença de OS.Incorporating starch into the poly(butylene adipate-co-terephthalate (PBAT polymer by means of blends with high starch contents is a possible option for producing biodegradable packaging using renewable resources and reducing costs. However, the addition of starch increases the water vapour permeability (WVP. The incorporation of substances as lipids and surfactants can reduce the hydrophilicity of films containing starch, favouring their use as packaging. The hydrophilicity of films produced from blends of starch/PBAT with added soybean oil (SO and tween 80 (TW was studied. The effects of these substances on the sorption isotherm, on the WVP and on the water vapour diffusion (Dw and solubility (β coefficients of the films were evaluated. The water sorption in films with SO, with or without TW

  15. Retarded acid emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Fast, C.R.; Rixe, F.H.; Duffield, E.L. Jr.

    1972-08-01

    Compositions for use in acidizing hydrocarbon-bearing formations are described. Retarded acid emulsions of prolonged stability make it possible for the acid in this form to be displaced substantial distances out into the formation before becoming spent. The action of acid emulsions for use in acidizing hydrocarbon-bearing formations is prolonged by employing as the principal emulsifying agent an amine salt of dodecylbenzene sulfonic acid. Acid emulsions employing the amine salt of dodecylbenzene sulfonic acid exhibit greater stability than those employing the free acid. (8 claims)

  16. Acid Lipase Disease

    Science.gov (United States)

    ... Enhancing Diversity Find People About NINDS NINDS Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, ... Related NINDS Publications and Information What is Acid Lipase Disease ? Acid lipase disease or deficiency occurs when ...

  17. Plasma amino acids

    Science.gov (United States)

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  18. POLYELEOSTEARIC ACID VESICLES

    Institute of Scientific and Technical Information of China (English)

    LI Zichen; XIE Ximng; FAN Qinghua; FANG Yifei

    1992-01-01

    α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solutionofeleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.

  19. Acid distribution in phosphoric acid fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Okae, I.; Seya, A.; Umemoto, M. [Fuji Electric Co., Ltd., Chiba (Japan)

    1996-12-31

    Electrolyte acid distribution among each component of a cell is determined by capillary force when the cell is not in operation, but the distribution under the current load conditions had not been clear so far. Since the loss of electrolyte acid during operation is inevitable, it is necessary to store enough amount of acid in every cell. But it must be under the level of which the acid disturbs the diffusion of reactive gases. Accordingly to know the actual acid distribution during operation in a cell is very important. In this report, we carried out experiments to clarify the distribution using small single cells.

  20. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Science.gov (United States)

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  1. Acid Deposition Phenomena

    International Nuclear Information System (INIS)

    Acid deposition, commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as wet deposition (rain, snow, cloud, fog) or dry deposition (dry particles, gas). Rain and snow are already naturally acidic, but are only considered problematic when less than a ph of 5.0 The main chemical precursors leading to acidic conditions are atmospheric concentrations of sulfur dioxide (SO2) and nitrogen oxides (NOx). When these two compounds react with water, oxygen, and sunlight in the atmosphere, the result is sulfuric (H2SO4) and nitric acids (HNO3), the primary agents of acid deposition which mainly produced from the combustion of fossil fuel and from petroleum refinery. Airborne chemicals can travel long distances from their sources and can therefore affect ecosystems over broad regional scales and in locations far from the sources of emissions. According to the concern of petroleum ministry with the environment and occupational health, in this paper we will discussed the acid deposition phenomena through the following: Types of acidic deposition and its components in the atmosphere Natural and man-made sources of compounds causing the acidic deposition. Chemical reactions causing the acidic deposition phenomenon in the atmosphere. Factors affecting level of acidic deposition in the atmosphere. Impact of acid deposition. Procedures for acidic deposition control in petroleum industry

  2. Plasma amino acids

    Science.gov (United States)

    Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

  3. The Acid Rain Reader.

    Science.gov (United States)

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  4. Acid Rain Study Guide.

    Science.gov (United States)

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  5. Azetidinic amino acids

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie;

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form fr...

  6. Immunoglobulin and fatty acids

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising 0.1-10 w/w % immunoglobulin (Ig), 4-14 w/w % saturated fatty acids, 4-14 w/w % mono-unsaturated fatty acids and 0-5 w/w % poly-unsaturated fatty acids, wherein the weight percentages are based on the content of dry matter in the composition...

  7. Organic-Acid-Assisted Fabrication of Low-Cost Li-Rich Cathode Material (Li[Li1/6Fe1/6Ni1/6Mn1/2]O-2) for Lithium-Ion Battery

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Taolin; Chen, Shi; Li, Li; Zhang, Xiaoxiao; Wu, Huiming; Wu, Tianpin; Sun, Cheng-Jun; Chen, Renjie; Wu, Feng; Lu, Jun; Amine, Khalil

    2014-12-24

    A novel Li-rich cathode Li[Li1/6Fe1/6Ni1/6Mn1/2]O-2 (0.4Li(2)MnO(3-)0.6LiFe(1/3)Ni(1/3)Mn(1/3)O(2)) was synthesized by a solgel method, which uses citric acid (SC), tartaric acid (ST), or adipic acid (SA) as a chelating agent. The structural, morphological, and electrochemical properties of the prepared samples were characterized by various methods. X-ray diffraction showed that single-phase materials are formed mainly with typical alpha-NaFeO2 layered structure (R3 m), and the SC sample has the lowest Li/Ni cation disorder. The morphological study indicated homogeneous primary particles in good distribution size (100 nm) with small aggregates. The Fe, Ni, and Mn valences were determined by X-ray absorption near-edge structure analysis. In coin cell tests, the initial reversible discharge capacity of an SA electrode was 289.7 mAh g(-1) at the 0.1C rate in the 1.54.8 V voltage range, while an SC electrode showed a better cycling stability with relatively high capacity retention. At the 2C rate, the SC electrode can deliver a discharge capacity of 150 mAh g(-1) after 50 cycles. Differential capacity vs voltage curves were employed to further investigate the electrochemical reactions and the structural change process during cycling. This low-cost, Fe-based compound prepared by the solgel method has the potential to be used as the high capacity cathode material for Liion batteries.

  8. Cleavage of nucleic acids

    Science.gov (United States)

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    2000-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  9. Acidizing carbonate reservoirs with chlorocarboxylic acid salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, E.A.; Scheuerman, R.F.; Templeton, C.C.

    1978-10-31

    A carbonate reservoir is acidized slowly by injecting an aqueous solution of a chlorocarboxylic acid salt so that the rate of the acidization is limited to the rate at which an acid is formed by the hydrolyzing of the chlorocarboxylate ions. The rate at which a chlorocarboxylic acid salt hydrolyzes to form an acid provides the desired rate of acid-release. A more complete acid-base reaction by chloroacetic acid, as compared to formic, acetic, and proprionic, is due to its being a much stronger acid. The pKa of chloroacetic acid is 2.86, whereas that of formic acid is 3.75, and that of acetic acid is 4.75. The pKa of a solution of a weak acid is the pH exhibited when the concentration of undissociated acid equals the concentration of the acid anion. 14 claims.

  10. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition. PMID:27175515

  11. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

  12. Interactions of methylamine and ammonia with atmospheric nucleation precursor H2SO4 and common organic acids: Thermodynamics and atmospheric implications

    Science.gov (United States)

    Xu, Y.; Nadykto, A. B.; Jiang, L.; Bai, Z.

    2016-06-01

    Interactions of the two common atmospheric bases, ammonia (NH3) and methylamine MA (CH3NH2), which are considered to be important stabilizers of binary clusters in the Earth's atmosphere, with H2SO4, the key atmospheric precursor, and 14 common atmospheric organic acids (COA) (formic (CH2O2), acetic (C2H4O2), oxalic (C2H2O4), malonic (C3H4O4), succinic (C4H6O4), glutaric acid (C5H8O4), adipic (C6H10O4), benzoic (C6H5COOH), phenylacetic (C6H5CH2COOH), pyruvic (C3H4O3), maleic acid (C4H4O4), malic (C4H6O5), tartaric (C4H6O6) and pinonic acid (C10H16O3)) have been studied using the composite high-accuracy G3MP2 method. The thermodynamic stability of mixed (COA) (H2SO4), (COA)(B1) and (COA)(B2) dimers and (COA) (H2SO4) (B1) and (COA) (H2SO4) (B1) trimers, where B1 and B2 represent methylamine (CH3NH2) and ammonia (NH3), respectively, have been investigated and their impacts on the thermodynamic stability of clusters containing H2SO4 have been analyzed. It has been shown that in many cases the interactions of H2SO4 with COA, ammonia and methylamine lead to the formation of heteromolecular dimers and trimers, which are certainly more stable than (H2SO4)2 and (H2SO4)3. It has also been found that free energies of (COA) (H2SO4)+ CH3NH2⇔(COA) (H2SO4)(CH3NH2) reactions exceed 10-15 kcal mol-1. This is a clear indication that mixed trimers composed of COA, H2SO4 and methylamine are very stable and can thus serve as possible nucleation sites. The present study leads us to conclude that the interactions of COA coexisting with H2SO4 and common atmospheric bases in the Earth's atmosphere may be an important factor affecting the stability of nucleating sulfuric acid clusters and that the impacts of COA on atmospheric nucleation should be studied in further details.

  13. Microorganisms for producing organic acids

    Energy Technology Data Exchange (ETDEWEB)

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

    Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

  14. Acid-Base Homeostasis.

    Science.gov (United States)

    Hamm, L Lee; Nakhoul, Nazih; Hering-Smith, Kathleen S

    2015-12-01

    Acid-base homeostasis and pH regulation are critical for both normal physiology and cell metabolism and function. The importance of this regulation is evidenced by a variety of physiologic derangements that occur when plasma pH is either high or low. The kidneys have the predominant role in regulating the systemic bicarbonate concentration and hence, the metabolic component of acid-base balance. This function of the kidneys has two components: reabsorption of virtually all of the filtered HCO3(-) and production of new bicarbonate to replace that consumed by normal or pathologic acids. This production or generation of new HCO3(-) is done by net acid excretion. Under normal conditions, approximately one-third to one-half of net acid excretion by the kidneys is in the form of titratable acid. The other one-half to two-thirds is the excretion of ammonium. The capacity to excrete ammonium under conditions of acid loads is quantitatively much greater than the capacity to increase titratable acid. Multiple, often redundant pathways and processes exist to regulate these renal functions. Derangements in acid-base homeostasis, however, are common in clinical medicine and can often be related to the systems involved in acid-base transport in the kidneys.

  15. Bile acid sequestrants

    DEFF Research Database (Denmark)

    Hansen, Morten; Sonne, David P; Knop, Filip K

    2014-01-01

    Bile acids are synthesized in the liver from cholesterol and have traditionally been recognized for their role in absorption of lipids and in cholesterol homeostasis. In recent years, however, bile acids have emerged as metabolic signaling molecules that are involved in the regulation of lipid...... and glucose metabolism, and possibly energy homeostasis, through activation of the bile acid receptors farnesoid X receptor (FXR) and TGR5. Bile acid sequestrants (BASs) constitute a class of drugs that bind bile acids in the intestine to form a nonabsorbable complex resulting in interruption...... of the enterohepatic circulation. This increases bile acid synthesis and consequently reduces serum low-density lipoprotein cholesterol. Also, BASs improve glycemic control in patients with type 2 diabetes. Despite a growing understanding of the impact of BASs on glucose metabolism, the mechanisms behind their glucose...

  16. Citric Acid Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Lewis, Pattie L. (Compiler)

    2013-01-01

    The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

  17. Docosahexaenoic Acid Neurolipidomics

    OpenAIRE

    Niemoller, Tiffany D.; Bazan, Nicolas G.

    2009-01-01

    Mediator lipidomics is a field of study concerned with the characterization, structural elucidation and bioactivity of lipid derivatives generated by enzymatic activity. Omega-3 fatty acids have beneficial effects for vision, brain function, cardiovascular function, and immune-inflammatory responses. Docosahexaenoic acid [DHA; 22:6(n-3)], the most abundant essential omega-3 fatty acid in the human body, is selectively enriched and avidly retained in the central nervous system as an acyl chain...

  18. The acid rain primer

    International Nuclear Information System (INIS)

    Acid rain continues to be a major problem in North America, and particularly in eastern Canada. This report introduced the topic of acid rain and discussed its formation, measurement, sources, and geographic distribution. The major sources of sulphur dioxide in Canada are smelting metals, burning coal for electrical power generation, industrial emissions (e.g., pulp and paper, petroleum and aluminum industry), and oil and gas extraction and refining. In Canada, the largest source of nitrogen oxide is the burning of fossil fuels by the transportation sector. Problem areas for acid rain in Canada were identified. The effects of acid rain were examined on lakes and aquatic ecosystems, forests and soils, human-made structures and materials, human health, and on visibility. Acid rain policies and programs were then presented from a historical and current context. Ecosystem recovery from acid rain was discussed with reference to acid rain monitoring, atmospheric response to reductions in acid-causing emissions, and ecosystem recovery of lakes, forests, and aquatic ecosystems. Challenges affecting ecosystem recovery were also presented. These challenges include drought and dry weather, decrease of base cations in precipitation, release of sulphate previously stored in soil, mineralization and immobilization of sulphur/sulphates. Last, the report discussed what still needs to be done to improve the problem of acid rain as well as future concerns. These concerns include loss of base cations from forested watersheds and nitrogen deposition and saturation. 21 refs., 2 tabs., 17 figs

  19. USGS Tracks Acid Rain

    Science.gov (United States)

    Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

    1995-01-01

    The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

  20. THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE

    Science.gov (United States)

    This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

  1. Omega-3 Fatty Acids

    Science.gov (United States)

    Omega-3 fatty acids are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount of triglycerides ( ... the blood in people with very high triglycerides. Omega-3 fatty acids are in a class of medications called antilipemic ...

  2. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  3. Locked nucleic acid

    DEFF Research Database (Denmark)

    Jepsen, Jan Stenvang; Sørensen, Mads D; Wengel, Jesper;

    2004-01-01

    Locked nucleic acid (LNA) is a class of nucleic acid analogs possessing very high affinity and excellent specificity toward complementary DNA and RNA, and LNA oligonucleotides have been applied as antisense molecules both in vitro and in vivo. In this review, we briefly describe the basic...

  4. Amino Acid Crossword Puzzle

    Science.gov (United States)

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  5. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  6. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  7. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  8. Uric acid - blood

    Science.gov (United States)

    ... High levels of uric acid can sometimes cause gout or kidney disease. You may have this test if you have had or are about to have certain types of chemotherapy. Rapid weight loss, which may occur with such treatments, can increase the amount of uric acid in ...

  9. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from...

  10. Carbolic acid poisoning

    Science.gov (United States)

    ... you to. If the person swallowed the carbolic acid, give them water or milk right away, if a provider tells ... well someone does depends on how much carbolic acid they swallowed and how quickly they receive treatment. The faster medical help is given, the better ...

  11. Neurotoxicity of Folic Acid

    NARCIS (Netherlands)

    Amsterdam van JGC; Jansen EHJM; A Opperhuizen; TOX

    2004-01-01

    The present review summarises the neurotoxicological effects of folic acid. Some studies in animals have shown that folic acid is neurotoxic and epileptogenic when applied directly to the brain. One poorly controlled and not further reproduced study from 1970 reported neurotoxic symptoms like malais

  12. Salicylic Acid Topical

    Science.gov (United States)

    ... skin blemishes in people who have acne. Topical salicylic acid is also used to treat skin conditions that involve scaling or overgrowth of skin ... water for 15 minutes.Do not apply topical salicylic acid to skin that is broken, red, swollen, irritated, or infected. ...

  13. 21 CFR 74.3102 - FD&C Blue No. 2.

    Science.gov (United States)

    2010-04-01

    ... copolymer of adipic acid and hexamethylene diamine) surgical sutures for use in general surgery subject to... Food, Drug, and Cosmetic Act with respect to the medical device in which the color additive FD&C...

  14. The Influence of Additives on Crystallization of Polyvinyl Chloride

    Institute of Scientific and Technical Information of China (English)

    LIU Yaqun; ZHANG Chaocan

    2007-01-01

    Acetanilide, adipic acid and potassium hydrogen phthalate were chosen as nucleating agents of polyvinyl chloride(PVC), and their effects on PVC crystallization were studied by differential scanning calorimetry, wide angle X-ray diffraction and fourier transform infrared spectroscopy. The experimental results indicate that all of the three additives are compatible with PVC to some extent, but adipic acid's compatibility with PVC is less satisfactory. The three additives can improve PVC crystallinity, and acetanilide can decrease PVC glass transition temperature(Tg)and narrow PVC melting range, while adipic acid and potassium hydrogen phthalate rise Tg of PVC and widen its melting range. All additives do not affect PVC crystal system and all samples are in orthorhombic system. All additives can improve (200), (110), (210) and (201, 111) planes growing. Moreover, acetanilide and adipic acid can shrink PVC spacings and improve the crystal perfection of PVC, but potassium hydrogen phthalate swells spacings and reduces the perfection of PVC crystal.

  15. Fusidic acid in dermatology

    DEFF Research Database (Denmark)

    Schöfer, Helmut; Simonsen, Lene

    1995-01-01

    Studies on the clinical efficacy of fusidic acid in skin and soft-tissue infections (SSTIs), notably those due to Staphylococcus aureus, are reviewed. Oral fusidic acid (tablets dosed at 250 mg twice daily, or a suspension for paediatric use at 20 mg/kg/day given as two daily doses) has shown good...... efficacy and tolerability. Similarly, plain fusidic acid cream or ointment used two or three times daily in SSTIs such as impetigo are clinically and bacteriologically effective, with minimal adverse events. Combination formulations of fusidic acid with 1% hydrocortisone or 0.1% betamethasone achieve...... excellent results in infected eczema by addressing both inflammation and infection. A new lipid-rich combination formulation provides an extra moisturizing effect. Development of resistance to fusidic acid has remained generally low or short-lived and can be minimized by restricting therapy to no more than...

  16. 21 CFR 172.860 - Fatty acids.

    Science.gov (United States)

    2010-04-01

    ... acid, caprylic acid, lauric acid, myristic acid, oleic acid, palmitic acid, and stearic acid. (b) The... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Fatty acids. 172.860 Section 172.860 Food and Drugs... Multipurpose Additives § 172.860 Fatty acids. The food additive fatty acids may be safely used in food and...

  17. Gluconic acid production.

    Science.gov (United States)

    Anastassiadis, Savas; Morgunov, Igor G

    2007-01-01

    Gluconic acid, the oxidation product of glucose, is a mild neither caustic nor corrosive, non toxic and readily biodegradable organic acid of great interest for many applications. As a multifunctional carbonic acid belonging to the bulk chemicals and due to its physiological and chemical characteristics, gluconic acid itself, its salts (e.g. alkali metal salts, in especially sodium gluconate) and the gluconolactone form have found extensively versatile uses in the chemical, pharmaceutical, food, construction and other industries. Present review article presents the comprehensive information of patent bibliography for the production of gluconic acid and compares the advantages and disadvantages of known processes. Numerous manufacturing processes are described in the international bibliography and patent literature of the last 100 years for the production of gluconic acid from glucose, including chemical and electrochemical catalysis, enzymatic biocatalysis by free or immobilized enzymes in specialized enzyme bioreactors as well as discontinuous and continuous fermentation processes using free growing or immobilized cells of various microorganisms, including bacteria, yeast-like fungi and fungi. Alternatively, new superior fermentation processes have been developed and extensively described for the continuous and discontinuous production of gluconic acid by isolated strains of yeast-like mold Aureobasidium pullulans, offering numerous advantages over the traditional discontinuous fungi processes.

  18. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    , chlorinated lipids have been found in meat exposed to hypochlorite disinfected water, and in chlorine-treated flour and in products made from such flour. Following exposure to chlorine bleached pulp mill effluents, aquatic organisms may have elevated concentrations of chlorinated fatty acids in their lipids......Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also...

  19. [Hydrofluoric acid burns].

    Science.gov (United States)

    Holla, Robin; Gorter, Ramon R; Tenhagen, Mark; Vloemans, A F P M Jos; Breederveld, Roelf S

    2016-01-01

    Hydrofluoric acid is increasingly used as a rust remover and detergent. Dermal contact with hydrofluoric acid results in a chemical burn characterized by severe pain and deep tissue necrosis. It may cause electrolyte imbalances with lethal consequences. It is important to identify high-risk patients. 'High risk' is defined as a total affected body area > 3% or exposure to hydrofluoric acid in a concentration > 50%. We present the cases of three male patients (26, 31, and 39 years old) with hydrofluoric acid burns of varying severity and describe the subsequent treatments. The application of calcium gluconate 2.5% gel to the skin is the cornerstone of the treatment, reducing pain as well as improving wound healing. Nails should be thoroughly inspected and possibly removed if the nail is involved, to ensure proper healing. In high-risk patients, plasma calcium levels should be evaluated and cardiac monitoring is indicated.

  20. Difficult Decisions: Acid Rain.

    Science.gov (United States)

    Miller, John A.; Slesnick, Irwin L.

    1989-01-01

    Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

  1. Folic acid in diet

    Science.gov (United States)

    ... green leafy vegetables Dried beans and peas (legumes) Citrus fruits and juices Fortified means that vitamins have ... A.D.A.M. Editorial team. Related MedlinePlus Health Topics Folic Acid Browse the Encyclopedia A.D. ...

  2. Omega-6 Fatty Acids

    Science.gov (United States)

    ... are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean oils. Other types of ... in black currant seed, borage seed, and evening primrose oils. Omega-6 fatty acids are used for ...

  3. Acid rain: An overview

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary of the effects of acid rain and related processes, sources, issues, corrective actions, research, current law, potential solutions, political solutions,...

  4. Stomach acid test

    Science.gov (United States)

    Gastric acid secretion test ... The test is done after you have not eaten for a while so fluid is all that remains in ... injected into your body. This is done to test the ability of the cells in the stomach ...

  5. Citric acid urine test

    Science.gov (United States)

    ... usually done while you are on a normal diet. Ask your provider for more information. ... acidosis and a tendency to form calcium kidney stones. The ... acid levels: A high carbohydrate diet Estrogen therapy Vitamin D

  6. Amino acid racemisation dating

    Energy Technology Data Exchange (ETDEWEB)

    Murray-Wallace, C.V. [University of Wollongong, Wollongong, NSW (Australia). School of Geosciences

    1999-11-01

    The potential of the time-dependent amino acid racemisation reaction as a method of age assessment was first reported by Hare and Abelson (1968). They noted that in specimens of the bivalve mollusc Mercenaria sp., greater concentrations of amino acids in the D-configuration with increasing fossil age. Hare and Abelson (1968) also reported negligible racemisation in a modern specimen of Mecanaria sp. On this basis they suggested that the extent of amino acid racemisation (epimerisation in the case of isoleucine) may be used to assess the age of materials within and beyond the range of radiocarbon dating. For the past thirty years amino acid racemisation has been extensively applied in Quaternary research as a method of relative and numeric dating, and a particularly large literature has emerged on the subject 12 refs.

  7. Amino Acid Metabolism Disorders

    Science.gov (United States)

    Metabolism is the process your body uses to make energy from the food you eat. Food is ... One group of these disorders is amino acid metabolism disorders. They include phenylketonuria (PKU) and maple syrup ...

  8. Azelaic Acid Topical

    Science.gov (United States)

    ... pores and by decreasing production of keratin, a natural substance that can lead to the development of ... acid controls acne and rosacea but does not cure these conditions. It may take 4 weeks or ...

  9. Neutron Nucleic Acid Crystallography.

    Science.gov (United States)

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination.

  10. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles...

  11. Method for isolating nucleic acids

    Science.gov (United States)

    Hurt, Jr., Richard Ashley; Elias, Dwayne A.

    2015-09-29

    The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

  12. Acidification and Acid Rain

    Science.gov (United States)

    Norton, S. A.; Veselã½, J.

    2003-12-01

    Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that

  13. Acid Rain, pH & Acidity: A Common Misinterpretation.

    Science.gov (United States)

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  14. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

  15. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  16. EFFECT OF ACIDITY ON ACID-SENSITIVE UV CURING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Qi-dao Chen; Bing Wu; Xiao-yin Hong

    1999-01-01

    By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.

  17. Chemistry and electrochemistry in trifluoroacetic acid. Comparison with acetic acid

    International Nuclear Information System (INIS)

    As the trifluoroacetic acid is, with the acetic acid, one of most often used carboxylic acids as solvent, notably in organic chemistry, this research thesis addresses some relatively simple complexing and redox reactions to highlight the peculiar feature of this acid, and to explain its very much different behaviour with respect to acetic acid. The author develops the notion of acidity level in solvents of low dielectric constant. The second part addresses a specific solvent: BF3(CH3COOH)2. The boron trifluoride strengthens the acidity of acetic acid and modifies its chemical and physical-chemical properties. In the third part, the author compares solvent properties of CF3COOH and CH3COOH. Noticed differences explain why the trifluoroacetic acid is a more interesting reaction environment than acetic acid for reactions such as electrophilic substitutions or protein solubilisation

  18. Determination of Sialic Acids by Acidic Ninhydrin Reaction

    Directory of Open Access Journals (Sweden)

    Yao,Kenzabroh

    1987-12-01

    Full Text Available A new acidic ninhydrin method for determining free sialic acids is described. The method is based on the reaction of sialic acids with Gaitonde's acid ninhydrin reagent 2 which yields a stable color with an absorption maximum at 470 nm. The standard curve is linear in the range of 5 to 500 nmol of N-acetylneuraminic acid per 0.9 ml of reaction mixture. The reaction was specific only for sialic acids among the various sugars and sugar derivatives examined. Some interference of this method by cysteine, cystine and tryptophan was noted, although their absorption maxima differed from that of sialic acids. The interference by these amino acids was eliminated with the use of a small column of cation-exchange resin. The acidic ninhydrin method provides a simple and rapid method for the determination of free sialic acids in biological materials.

  19. Improving the pH-response of pHLIP insertion at tumor acidity for targeted drug delivery against cancer: Biophysical studies in model membranes and evaluations in cells

    Science.gov (United States)

    Onyango, Joab Otieno

    pH (Low) Insertion Peptide (pHLIP) possesses unique qualities that can be applied in cancer biology. It is a peptide that lives in three worlds: In State I, pHLIP exists as an unstructured monomer in solution at neutral pH; In State II, pHLIP partitions to the surface of a lipid bilayer at neutral pH; In State III, pHLIP inserts across the lipid bilayer by forming a transmembrane (TM) alpha helix under slightly acidic conditions (pH 6). These properties allow pHLIP to target acidosis (pH 6.5-7.0), a ubiquitous feature of solid tumors. Although pHLIP shows promise as a drug delivery vehicle, insertion properties such as pH50 (i.e. the pH at which 50% of pHLIP are inserted) and Hill coefficient must be tuned to improve tumor targeting and drug delivery in vivo. When TM region D14 and D25 residues were replaced with two glutamic acid residues as well as noncanonical amino acids such as alpha amino adipic acid (Aad) and gamma carboxyglutamic acid (Gla), we discovered pHLIP variants that possess a pH50 that can match tumor extracellular pH. pHLIP variants D25EE, Asp25Aad, and Asp14Gla/Asp25Aad, insert with pH50 of 6.60, 6.74, and 6.79, respectively. We also tuned pH-response (cooperativity of insertion) and we found that the Asp14Gla variant can insert into membrane with the sharpest transition observed so far for a pHLIP (i.e. over half pH unit vs. one pH unit for WT). Furthermore, we used turn-on fluorescence to evaluate the new variants in cancer cells. The most promising Asp25Aad pHLIP gave near theoretical maximum level of dequenching in cancerous A549 cells at pH 6.2 and 6.4, indicating a high level of plasma-membrane insertion. Under the same conditions, the `WT' and D25E pHLIP variants have low levels of plasma-membrane insertion in cells. Dequenching levels were low in non-cancerous HK2 cell line.

  20. Domoic Acid Epileptic Disease

    Directory of Open Access Journals (Sweden)

    John S. Ramsdell

    2014-03-01

    Full Text Available Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis.

  1. A Demonstration of Acid Rain

    Science.gov (United States)

    Fong, Man Wai

    2004-01-01

    A demonstration showing acid rain formation is described. Oxides of sulfur and nitrogen that result from the burning of fossil fuels are the major pollutants of acid rain. In this demonstration, SO[subscript 2] gas is produced by the burning of matches. An acid-base indicator will show that the dissolved gas turns an aqueous solution acidic.

  2. Amino acid analysis.

    Science.gov (United States)

    Crabb, J W; West, K A; Dodson, W S; Hulmes, J D

    2001-05-01

    Amino acid analysis (AAA) is one of the best methods to quantify peptides and proteins. Two general approaches to quantitative AAA exist, namely, classical postcolumn derivatization following ion-exchange chromatography and precolumn derivatization followed by reversed-phase HPLC (RP-HPLC). Excellent instrumentation and several specific methodologies are available for both approaches, and both have advantages and disadvantages. This unit focuses on picomole-level AAA of peptides and proteins using the most popular precolumn-derivatization method, namely, phenylthiocarbamyl amino acid analysis (PTC-AAA). It is directed primarily toward those interested in establishing the technology with a modest budget. PTC derivatization and analysis conditions are described, and support and alternate protocols describe additional techniques necessary or useful for most any AAA method--e.g., sample preparation, hydrolysis, instrument calibration, data interpretation, and analysis of difficult or unusual residues such as cysteine, tryptophan, phosphoamino acids, and hydroxyproline. PMID:18429107

  3. Biodegradation of cyanuric acid.

    Science.gov (United States)

    Saldick, J

    1974-12-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO(2) and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand.

  4. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    Halogenated fatty acids are the major contributors to organohalogen compounds in lipids of marine mammals, fish, and bivalves. For the initial characterization of these recently noticed compounds, a determination of the halogen concentration has usually been combined with some lipid isolation...... and separation method. This review covers separation by solid phase chromatography, gel permeation chromatography, and liquid-liquid extraction, followed by halogen determination. All studies performed according to this outline have indicated that the major organohalogen compounds are chlorinated fatty acids...... bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD...

  5. Calorimetry of Nucleic Acids.

    Science.gov (United States)

    Rozners, Eriks; Pilch, Daniel S; Egli, Martin

    2015-12-01

    This unit describes the application of calorimetry to characterize the thermodynamics of nucleic acids, specifically, the two major calorimetric methodologies that are currently employed: differential scanning (DSC) and isothermal titration calorimetry (ITC). DSC is used to study thermally induced order-disorder transitions in nucleic acids. A DSC instrument measures, as a function of temperature (T), the excess heat capacity (C(p)(ex)) of a nucleic acid solution relative to the same amount of buffer solution. From a single curve of C(p)(ex) versus T, one can derive the following information: the transition enthalpy (ΔH), entropy (ΔS), free energy (ΔG), and heat capacity (ΔCp); the state of the transition (two-state versus multistate); and the average size of the molecule that melts as a single thermodynamic entity (e.g., the duplex). ITC is used to study the hybridization of nucleic acid molecules at constant temperature. In an ITC experiment, small aliquots of a titrant nucleic acid solution (strand 1) are added to an analyte nucleic acid solution (strand 2), and the released heat is monitored. ITC yields the stoichiometry of the association reaction (n), the enthalpy of association (ΔH), the equilibrium association constant (K), and thus the free energy of association (ΔG). Once ΔH and ΔG are known, ΔS can also be derived. Repetition of the ITC experiment at a number of different temperatures yields the ΔCp for the association reaction from the temperature dependence of ΔH.

  6. [Nicotinic acid and nicotinamide].

    Science.gov (United States)

    Kobayashi, M; Shimizu, S

    1999-10-01

    Nicotinic acid and nicotinamide are called niacin. They are the antipellagra vitamin essential to many animals for growth and health. In human being, niacin is believed necessary together with other vitamins for the prevention and cure of pellagra. Niacin is widely distributed in nature; appreciable amounts are found in liver, fish, yeast and cereal grains. Nicotinamide is a precursor of the coenzyme NAD and NADP. Some of the most understood metabolic processes that involve niacin are glycolysis, fatty acid synthesis and respiration. Niacin is also related to the following diseases: Hartnup disease; blue diaper syndrome; tryptophanuria; hydroxykynureninuria; xanthurenic aciduria; Huntington's disease. PMID:10540864

  7. Whither Acid Rain?

    OpenAIRE

    Peter Brimblecombe

    2000-01-01

    Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and s...

  8. 2-arylureidobenzoic acids

    DEFF Research Database (Denmark)

    Valgeirsson, Jon; Nielsen, Elsebet Ø; Peters, Dan;

    2003-01-01

    A series of 2-arylureidobenzoic acids (AUBAs) was prepared by a short and effective synthesis, and the pharmacological activity at glutamate receptors was evaluated in vitro and in vivo. The compounds showed noncompetitive antagonistic activity at the kainate receptor subtype GluR5. The most potent...... on the benzoic acid moiety (ring A), whereas ring B tolerated a variety of substituents, but with a preference for lipophilic substituents. The most potent compounds had a 4-chloro substituent on ring A and 3-chlorobenzene (6b), 2-naphthalene (8h), or 2-indole (8k) as ring B and had IC(50) values of 1.3, 1...

  9. NITRIC ACID PICKLING PROCESS

    Science.gov (United States)

    Boller, E.R.; Eubank, L.D.

    1958-08-19

    An improved process is described for the treatment of metallic uranium surfaces preparatory to being given hot dip coatings. The process consists in first pickling the uraniunn surInce with aqueous 50% to 70% nitric acid, at 60 to 70 deg C, for about 5 minutes, rinsing the acid solution from the uranium article, promptly drying and then passing it through a molten alkali-metal halide flux consisting of 42% LiCl, 53% KCla and 5% NaCl into a molten metal bath consisting of 85 parts by weight of zinc and 15 parts by weight of aluminum

  10. Whither Acid Rain?

    Directory of Open Access Journals (Sweden)

    Peter Brimblecombe

    2000-01-01

    Full Text Available Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  11. Polyunsaturated fatty acids and inflammation

    OpenAIRE

    Calder Philip C

    2004-01-01

    The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites) and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and ...

  12. Fatty acids of Thiobacillus thiooxidans.

    Science.gov (United States)

    Levin, R A

    1971-12-01

    Fatty acid spectra were made on Thiobacillus thiooxidans cultures both in the presence and absence of organic compounds. Small additions of glucose or acetate had no significant effect either on growth or fatty acid content. The addition of biotin had no stimulatory effect but did result in slight quantitative changes in the fatty acid spectrum. The predominant fatty acid was a C(19) cyclopropane acid.

  13. Continuous cultivations of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus: Growth yields and morphological characterization

    DEFF Research Database (Denmark)

    Robin, Jarno Jacky Christian; Lettier, G.; Mcintyre, Mhairi;

    2003-01-01

    place in significant amounts only at dilution rates below 0.03 h(-1). After three to five residence times, adipate degradation and ad-7-ADCA production disappeared, and this allowed determination of the biomass yield coefficient on adipate. The morphology was measured at different dilution rates......The growth stoichiometry of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus was determined in glucose-limited chemostat cultivations using a chemically defined medium. This strain produces adipoyl-7-aminocleacetoxycephalosporanic acid (ad-7-ADCA) when...... it is fed with adipic acid. The biomass yield and maintenance coefficients for the strain were similar to those found for penicillin-producing strains of Penicillium chrysogenum. The maximum specific growth rate in the chemostat was found to be 0.11 h(-1). Metabolic degradation of adipate was found to take...

  14. Lactic acid bacterial cell factories for gamma-aminobutyric acid.

    Science.gov (United States)

    Li, Haixing; Cao, Yusheng

    2010-11-01

    Gamma-aminobutyric acid is a non-protein amino acid that is widely present in organisms. Several important physiological functions of gamma-aminobutyric acid have been characterized, such as neurotransmission, induction of hypotension, diuretic effects, and tranquilizer effects. Many microorganisms can produce gamma-aminobutyric acid including bacteria, fungi and yeasts. Among them, gamma-aminobutyric acid-producing lactic acid bacteria have been a focus of research in recent years, because lactic acid bacteria possess special physiological activities and are generally regarded as safe. They have been extensively used in food industry. The production of lactic acid bacterial gamma-aminobutyric acid is safe and eco-friendly, and this provides the possibility of production of new naturally fermented health-oriented products enriched in gamma-aminobutyric acid. The gamma-aminobutyric acid-producing species of lactic acid bacteria and their isolation sources, the methods for screening of the strains and increasing their production, the enzymatic properties of glutamate decarboxylases and the relative fundamental research are reviewed in this article. And the potential applications of gamma-aminobutyric acid-producing lactic acid bacteria were also referred to.

  15. Acid Rain Classroom Projects.

    Science.gov (United States)

    Demchik, Michael J.

    2000-01-01

    Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

  16. The Acid Rain Game.

    Science.gov (United States)

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  17. The Acid Rain Debate.

    Science.gov (United States)

    Oates-Bockenstedt, Catherine

    1997-01-01

    Details an activity designed to motivate students by incorporating science-related issues into a classroom debate. Includes "The Acid Rain Bill" and "Position Guides" for student roles as committee members, consumers, governors, industry owners, tourism professionals, senators, and debate directors. (DKM)

  18. Koetjapic acid chloroform hemisolvate

    Directory of Open Access Journals (Sweden)

    Z. D. Nassar

    2010-06-01

    Full Text Available The asymmetric unit of the title compound, C30H46O4·0.5CHCl3, consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS-7-(2-carboxyethyl-3,4b,7,10b,12a-pentamethyl-8-(prop-1-en-2-yl-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexadecahydrochrysene-3-carboxylic acid] molecule and one half-molecule of chloroform solvent, which is disordered about a twofold rotation axis. The symmetry-independent component is further disordered over two sites, with occupancies of 0.30 and 0.20. The koetjapic acid contains a fused four-ring system, A/B/C/D. The A/B, B/C and C/D junctions adopt E/trans/cis configurations, respectively. The conformation of ring A is intermediate between envelope and half-chair and ring B adopts an envelope conformation whereas rings C and D adopt chair conformations. A weak intramolecular C—H...O hydrogen bond is observed. The koetjapic acid molecules are linked into dimers by two pairs of intermolecular O—H...O hydrogen bonds. The dimers are stacked along the c axis.

  19. Acid Rain Investigations.

    Science.gov (United States)

    Hugo, John C.

    1992-01-01

    Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

  20. Lactic acid and lactates

    NARCIS (Netherlands)

    Schreurs, V.V.A.M.

    2010-01-01

    This review aims to integrate the present state of knowledge on lactate metabolism in human and mammalian physiology as far as it could be subject to nutritional interventions. An integrated view on the nutritional, metabolic and physiological aspects of lactic acid and lactates might open a perspec

  1. Hyaluronic Acid Assays

    DEFF Research Database (Denmark)

    Itenov, Theis Skovsgaard; Kirkby, Nikolai S; Bestle, Morten H;

    2015-01-01

    BACKGROUD: Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method. METHODS: HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme...

  2. Accidents with sulfuric acid

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2006-01-01

    Full Text Available Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eighteen years (from 1988 till the beginning of 2006 are analyzed in this paper. It is very alarming data that, according to all the recorded accidents, over 1.6 million tons of sulfuric acid were exuded. Although water transport is the safest (only 16.38% of the total amount of accidents in that way 98.88% of the total amount of sulfuric acid was exuded into the environment. Human factor was the common factor in all the accidents, whether there was enough control of the production process, of reservoirs or transportation tanks or the transport was done by inadequate (old tanks, or the accidents arose from human factor (inadequate speed, lock of caution etc. The fact is that huge energy, sacrifice and courage were involved in the recovery from accidents where rescue teams and fire brigades showed great courage to prevent real environmental catastrophes and very often they lost their lives during the events. So, the phrase that sulfuric acid is a real "environmental bomb" has become clearer.

  3. Acid Ceramidase in Melanoma

    DEFF Research Database (Denmark)

    Realini, Natalia; Palese, Francesca; Pizzirani, Daniela;

    2016-01-01

    Acid ceramidase (AC) is a lysosomal cysteine amidase that controls sphingolipid signaling by lowering the levels of ceramides and concomitantly increasing those of sphingosine and its bioactive metabolite, sphingosine 1-phosphate. In the present study, we evaluated the role of AC-regulated sphing...

  4. Zoledronic Acid Injection

    Science.gov (United States)

    ... blood cells that produce substances needed to fight infection)] or by cancer that began in another part of the body but has spread to the bones. Zoledronic acid (Zometa) is not cancer chemotherapy, and it will not slow or stop the ...

  5. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  6. Origin of fatty acids

    International Nuclear Information System (INIS)

    The appearance of fatty acids and membranes is one of the most important events of the prebiotic world because genesis of life required the compartmentalization of molecules. Membranes allowed cells to become enriched with molecules relevant for their evolution and gave rise to gradients convertible into energy. By virtue of their hydrophobic/hydrophilic interface, membranes developed certain enzymatic activities impossible in the aqueous phase. A prebiotic cell is an energy unit but it is also an information unit. It has a past, a present and a future. The biochemistry of fatty acids involves acetylCoA, malonylCoA and an enzyme, acyl synthetase, which joins both molecules. After substitution of the acetyl group in place of the carboxyl group of malonyl derivatives, the chain is reduced and dehydrated to crotonyl derivatives. These molecules can again react with malonylCoA to form unsaturated chain; they can also undergo a new reduction step to form butyryl derivatives which can react with malonylCoA to form a longer aliphatic chain. The formation of malonylCoA consumes ATP. The reduction step needs NADPH and proton. Dehydration requires structural information because the reduction product is chiral (D configuration). It is unlikely that these steps were possible in a prebiotic environment. Thus we have to understand how fatty acids could appear in the prebiotic era. This hypothesis about the origin of fatty acids is based on the chemistry of sulfonium ylides and sulfonium salts. The most well-known among these molecules are S-melthyl-methionine and S-adenosyl methionine. The simplest sulfonium cation is the trimethylsulfonium cation. Chemists have evidence that these products can produce olefin when they are heated or flashed with UV light in some conditions. I suggest that these volatile products can allow the formation of fatty acids chains in atmospheric phase with UV and temperature using methanol as starting material. Different synthetic pathways will be

  7. The Study of the Adhesive Activity and Modification Possibilities of Melamine-Urea-Formaldehyde (MUF), Urea-Formaldehyde (UF) Resins

    OpenAIRE

    Kajaks, J; Kolbins, A

    2014-01-01

    Two types of thermosetting resins MUF and UF have been used as glues for birch wood veneer. As resins modifiers polyvinylacetate emulsion (PVA), polyvinylbutiral (PVB) (powder and solution), rubber latex, adipic (Ad) and sebacic (Seb) acids have been utilized. For glued system shear strength and deformation, bending properties and impact strength have been tested. The best properties: adhesive activity and elasticity have been shown by resins modified with PVB powder, rubber latex, adipic and...

  8. Melt processing of polymer biocomposites

    OpenAIRE

    Juliana França Marinho; Natália Ferreira Braga; Annelise Krohn; Fernanda Salviano Myata; Luiz Henrique Silveira; Abner Cabral Neto; Guilhermino José Macêdo Fechine

    2015-01-01

    A coupled device extruder and injection moulding were used to prepare biocomposites in order to provide a continuous and large-scale production, and overcome the fiber degradation inside the extruder. Two types of biocomposites were prepared, Sisal/poly(buthylene adipate-co-terephthlate) – PBAT and Juta/poly(lactide acid)/poly(buthylene adipate-co-terephthlate) blend. The biocomposites were prepared with fiber as-received and alkaline treated. The mechanical properties of biocomposites were i...

  9. Potentiometric determination of peroxodisulfuric acid during electrolysis sulfuric acid

    Directory of Open Access Journals (Sweden)

    Fedor Malchik

    2013-09-01

    Full Text Available Was proposed two potentiometric methods for determining peroxodisulfuric acid during electrolysis of sulfuric acid (potentiometric titration method and direct potentiometry, based on its interaction with a known excess of a solution Fe2+.

  10. Arterial Blood Carbonic Acid Inversely Determines Lactic and Organic Acids

    OpenAIRE

    Aiken, Christopher Geoffrey Alexander

    2013-01-01

    Objective: To establish that arterial blood carbonic acid varies inversely with lactic acid in accordance with bicarbonate exchanging for lactate across cell membranes through the anion exchange mechanism to maintain the Gibbs-Donnan equilibrium.

  11. [Lipid synthesis by an acidic acid tolerant Rhodotorula glutinis].

    Science.gov (United States)

    Lin, Zhangnan; Liu, Hongjuan; Zhang, Jian'an; Wang, Gehua

    2016-03-01

    Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis. PMID:27349116

  12. Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells

    Directory of Open Access Journals (Sweden)

    Duan Rui-Dong

    2009-12-01

    Full Text Available Abstract Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-β-boswellic acids (AKBA, a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health.

  13. Acetic acid extraction from aqueous solutions using fatty acids

    NARCIS (Netherlands)

    IJmker, H.M.; Gramblicka, M.; Kersten, S.R.A.; Ham, van der A.G.J.; Schuur, B.

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  14. [Progress in glucaric acid].

    Science.gov (United States)

    Qiu, Yuying; Fang, Fang; Du, Guocheng; Chen, Jian

    2015-04-01

    Glucaric acid (GA) is derived from glucose and commonly used in chemical industry. It is also considered as one of the "Top value-added chemicals from biomass" as carbohydrate monomers to produce various synthetic polymers and bioenergy. The demand for GA in food manufacture is increasing. GA has also attracted public attentions due to its therapeutic uses such as regulating hormones, increasing the immune function and reducing the risks of cancers. Currently GA is produced by chemical oxidation. Research on production of GA via microbial synthesis is still at preliminary stage. We reviewed the advances of glucaric acid applications, preparation and quantification methods. The prospects on production of GA by microbial fermentation were also discussed. PMID:26380405

  15. Synthesis,Characterization and Comparison of Biodegradation Poly(ethylene terephthalate)Modified with Acid and Glycol%酸和醇改性可降解PET的合成表征和对比

    Institute of Scientific and Technical Information of China (English)

    姚雅文; 兰建武; 石坤; 黄夏; 贺雯

    2015-01-01

    Poly(ethylene adipate-co-ethylene terephthalate)(PEAT) and poly(hexanediol terephthalate-co-ethylene terephthalate) (PHET) was separately synthesized via melt polycondensation from dimethyl terephthalate(DMT),1,6-adipic acid(AA),1,6-hexylene glycol(HG),ethylene glycol(EG). Intrinsic viscosity,chemical structure and thermal properties were investigated by means of ubbelohde viscometer,FTIR,1H–NMR,DSC and TGA. The results show that PEAT and PHET are successfully synthesized,which are random copolyester. With the adding of AA and HG,melting point and decomposition point of the synthetic copolyesters shifted toward lower temperature,and the biodegradability can be greatly enhanced compared with PET. Compared with PEAT and PHET, it turns out that the thermal stability of PHET is a little bit better while the biodegradability is a little bit worse than PEAT.%采用熔融缩聚法,以对苯二甲酸二甲酯(DMT)、1,6–己二酸(AA)、1,6–己二醇(HG)和乙二醇(EG)为原料,将结构相近的AA和HG分别引入聚对苯二甲酸乙二酯(PET),合成了可降解聚对苯二甲酸乙二醇-co-己二酸乙二醇酯(PEAT)和聚对苯二甲酸乙二醇-co-对苯二甲酸己二醇酯(PHET),对比相似结构酸和醇对PET性能影响差别。采用乌式黏度计对PEAT和PHET的特性黏度进行了测试,通过傅立叶变换红外光谱(FTIR)、核磁共振氢谱(1H–NMR)、差示扫描量热分析(DSC)和热失重(TG)分析对其化学结构和热性能进行了研究和对比,通过酶降解,检测PEAT和PHET的可降解性能。结果表明,成功地合成了PEAT与PHET,且其为无规共聚物。AA和HG的加入,使聚酯的熔点和热分解温度有所降低,而且与PET相比,可降解性能明显提高。对比PEAT和PHET可知,PHET的热稳定性略优,可降解性略差。

  16. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2007-01-01

    Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness.......Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness....

  17. Retinoic acid and cancer treatment

    OpenAIRE

    Chen, Mei-Chih; Hsu, Shih-Lan; Lin, Ho; Yang, Tsung-Ying

    2014-01-01

    Retinoic acid which belongs to the retinoid class of chemical compounds is an important metabolite of vitamin A in diets. It is currently understood that retinoic acid plays important roles in cell development and differentiation as well as cancer treatment. Lung, prostate, breast, ovarian, bladder, oral, and skin cancers have been demonstrated to be suppressed by retinoic acid. Our results also show that low doses and high doses of retinoic acid may respectively cause cell cycle arrest and a...

  18. Acids and bases solvent effects on acid-base strenght

    CERN Document Server

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  19. Pantothenic acid biosynthesis in zymomonas

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

    2014-07-01

    Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

  20. An Umbrella for Acid Rain.

    Science.gov (United States)

    Randal, Judith

    1979-01-01

    The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

  1. Self-neutralizing well acidizing

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, E.A.; Scheuerman, R.F.

    1974-07-30

    A process for acidizing a subterranean region by contacting it with an acidic solution is improved by dissolving in the solution a pH-increasing reactant that subsequently adjusts the pH of the solution to a selected relatively neutral value. Urea is an example of the acid neutralizer. (10 claims)

  2. Acid Rain Limits Global Warming

    Institute of Scientific and Technical Information of China (English)

    Will Knight; 张林玲

    2004-01-01

    @@ Acid rain restricts global warming by reducing methane① emissions from natural wetland areas, suggests a global climate study. Acid rain is the result of industrial pollution,which causes rainwater to carry small quantities of acidic compoumds② such as sulphuric and nitric acid③. Contaminated rainwater can upset rivers and lakes, killing fish and other organisms and also damage plants, trees and buildings.

  3. Antibiofilm Properties of Acetic Acid

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup;

    2014-01-01

    -negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms....

  4. Heterogeneous uptake of amines by citric acid and humic acid.

    Science.gov (United States)

    Liu, Yongchun; Ma, Qingxin; He, Hong

    2012-10-16

    Heterogeneous uptake of methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) onto citric acid and humic acid was investigated using a Knudsen cell reactor coupled to a quadrupole mass spectrometer at 298 K. Acid-base reactions between amines and carboxylic acids were confirmed. The observed uptake coefficients of MA, DMA, and TMA on citric acid at 298 K were measured to be 7.31 ± 1.13 × 10(-3), 6.65 ± 0.49 × 10(-3), and 5.82 ± 0.68 × 10(-3), respectively, and showed independence of sample mass. The observed uptake coefficients of MA, DMA, and TMA on humic acid at 298 K increased linearly with sample mass, and the true uptake coefficients of MA, DMA, and TMA were measured to be 1.26 ± 0.07 × 10(-5), 7.33 ± 0.40 × 10(-6), and 4.75 ± 0.15 × 10(-6), respectively. Citric acid, having stronger acidity, showed a higher reactivity than humic acid for a given amine; while the steric effect of amines was found to govern the reactivity between amines and citric acid or humic acid.

  5. Molecular interaction of pinic acid with sulfuric acid

    DEFF Research Database (Denmark)

    Elm, Jonas; Kurtén, Theo; Bilde, Merete;

    2014-01-01

    We investigate the molecular interactions between the semivolatile α-pinene oxidation product pinic acid and sulfuric acid using computational methods. The stepwise Gibbs free energies of formation have been calculated utilizing the M06-2X functional, and the stability of the clusters is evaluated...... from the corresponding ΔG values. The first two additions of sulfuric acid to pinic acid are found to be favorable with ΔG values of -9.06 and -10.41 kcal/mol. Addition of a third sulfuric acid molecule is less favorable and leads to a structural rearrangement forming a bridged sulfuric acid-pinic acid...... cluster. The involvement of more than one pinic acid molecule in a single cluster is observed to lead to the formation of favorable (pinic acid)2(H2SO4) and (pinic acid)2(H2SO4)2 clusters. The identified most favorable growth paths starting from a single pinic acid molecule lead to closed structures...

  6. Ionic liquid supported acid-catalysed esterification of lauric acid

    International Nuclear Information System (INIS)

    Ionic Liquid (IL) based on 1-n-butyl-3-methylimidazolium bis(trifluoro methylsulfonyl)imide (BMI.NTf2) under acidic condition was used as catalyst for the esterification reaction of fatty acid. Various acids namely sulphuric acid, perchloric acid, p-toulene sulphonic acid and various chloride salts such as zinc chloride (ZnCl2) and iron (III) chloride (FeCl3) immobilized in ionic liquid BMI.NTf2 gave acidic ILs. These acidic ILs were tested as catalysts for esterification reactions. Esterification of alcohol (methanol) with fatty acid (lauric acid) using ionic liquid BMI.NTf2 combined with H2SO4 (BMI.NTf2(H2SO4)) gave high activity (>85 %) and selectivity (100 %) observed over a period of 2 hours reaction with reaction temperature 70 degree Celsius. The ester became easily separated due to IL forming biphasic with product after the reaction where ester accumulated as the upper phase and IL with water produced after reaction at lower phase. Catalytic activities comparison also be studied between acidic ionic liquid BMI.NTf2 with acidic ionic liquid ChCl.2ZnCl2 and conventional acid catalyst. These ILs were characterised by using FTIR, NMR and TGA. Results from FTIR were showed no significant difference between ILs with ILs in acidic condition. The TGA curve show BMI.NTf2 thermals decomposition is ≥400 degree Celsius but when BMI.NTf2 combination with H2SO4, TGA curve show weight loss increase and becomes unstable. The advantages of ILs as catalyst are clean process and green chemistry due to its behaviour such as non-volatile, no loss of solvent through evaporation and reduced environmentally impact. This ILs-catalyst system can be recycle for further reaction. (author)

  7. Microbial transformations of isocupressic acid.

    Science.gov (United States)

    Lin, S J; Rosazza, J P

    1998-07-01

    Microbial transformations of the labdane-diterpene isocupressic acid (1) with different microorganisms yielded several oxygenated metabolites that were isolated and characterized by MS and NMR spectroscopic analyses. Nocardia aurantia (ATCC 12674) catalyzed the cleavage of the 13,14-double bond to yield a new nor-labdane metabolite, 2. Cunninghamella elegans (-) (NRRL 1393) gave 7beta-hydroxyisocupressic acid (3) and labda-7,13(E)-diene-6beta,15, 17-triol-19-oic acid (4), and Mucor mucedo (ATCC 20094) gave 2alpha-hydroxyisocupressic acid (5) and labda-8(17),14-diene-2alpha, 13-diol-19-oic acid (6).

  8. Invasive cleavage of nucleic acids

    Science.gov (United States)

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    1999-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  9. Polyunsaturated fatty acids and inflammation

    Directory of Open Access Journals (Sweden)

    Calder Philip C.

    2004-01-01

    Full Text Available The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and so available for eicosanoid production. Thus, n-3 polyunsaturated fatty acids act as arachidonic acid antagonists. Components of both natural and acquired immunity, including the production of key inflammatory cytokines, can be affected by n-3 polyunsaturated fatty acids. Although some of the effects of n-3 fatty acids may be brought about by modulation of the amount and types of eicosanoids made, it is possible that these fatty acids might elicit some of their effects by eicosanoid-independent mechanisms. Such n-3 fatty acid-induced effects may be of use as a therapy for acute and chronic inflammation, and for disorders that involve an inappropriately-activated immune response.

  10. Mycophenolic Acid in Silage

    Science.gov (United States)

    Schneweis, Isabell; Meyer, Karsten; Hörmansdorfer, Stefan; Bauer, Johann

    2000-01-01

    We examined 233 silage samples and found that molds were present in 206 samples with counts between 1 × 103 and 8.9 × 107 (mean, 4.7 × 106) CFU/g. Mycophenolic acid, a metabolite of Penicillium roqueforti, was detected by liquid chromatography-mass spectrometry in 74 (32%) of these samples at levels ranging from 20 to 35,000 (mean, 1,400) μg/kg. This compound has well-known immunosuppressive properties, so feeding with contaminated silage may promote the development of infectious diseases in livestock. PMID:10919834

  11. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures...... and 82, respectively. The aminolactone 84 was converted into the corresponding amino sugar 89.With the aim of synthesising substrates for the Pictet-Spengler reaction three 4-aldehydo acetamidodideoxytetronolactones 92, 97 and 103 were prepared by periodate cleavage of the corresponding hexonolactones...

  12. Nucleic Acid Vaccines

    Institute of Scientific and Technical Information of China (English)

    LU Shan

    2004-01-01

    @@ Anew method of immunization was discovered in the early 1990s. Several research groups independently demonstrated that direct inoculation of DNA plasmids coding for a specific protein antigen could elicit immune responses against that antigen[1-4].Since in theory the mRNA molecules also have the potential to be translated into the protein antigen, this vaccination approach was officially named by WHO as the nucleic acid vaccination even though the term DNA vaccine has been used more commonly in the literature. This novel approach is considered the fourth generation of vaccines after live attenuated vaccines, killed or inactivated vaccines and recombinant protein based subunit vaccines.

  13. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    OpenAIRE

    B. Syama Sundar; P.S.Radhakrishna murti

    2014-01-01

    Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation wi...

  14. Growth of nitric acid hydrates on thin sulfuric acid films

    Science.gov (United States)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-05-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1 - 3 × 10-4 Torr H2O and 1 - 2.5 × 10-6 Torr HNO3) and subjected to cooling and heating cycles. FTIR spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  15. Caro's acid - its introduction to uranium acid leaching in Australia

    International Nuclear Information System (INIS)

    After extensive testing and plant trials to establish the benefits of Caro's acid (H2SO5) as an alternative oxidant, Queensland Mines Limited decided to replace pyrolusite with Caro's acid in its acid leach uranium treatment plant at Nabarlek. The decision was based on the reagent savings and environmental gains associated with the removal of manganese from the process liquors, as well as the labour savings and improved oxidation reduction potential control possible in leaching using the Caro's acid system. Some changes in operating parameters were necessary with the introduction of Caro's acid to the treatment plant. Operating results have confirmed the relationship between oxidant demand and uranium content of ore established during the trials. Acid savings have been as predicted from the plant trials. The major saving has been of hydrated lime required for tailings neutralisation

  16. Solid acid catalysis from fundamentals to applications

    CERN Document Server

    Hattori, Hideshi

    2014-01-01

    IntroductionTypes of solid acid catalystsAdvantages of solid acid catalysts Historical overviews of solid acid catalystsFuture outlookSolid Acids CatalysisDefinition of acid and base -Brnsted acid and Lewis acid-Acid sites on surfacesAcid strengthRole of acid sites in catalysisBifunctional catalysisPore size effect on catalysis -shape selectivity-Characterization of Solid Acid Catalysts Indicator methodTemperature programmed desorption (TPD) of ammoniaCalorimetry of adsorption of basic moleculesInfrare

  17. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

    Sandhu, G.K.; Singh, K.; Lark, B.S.;

    2002-01-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), n-hexanoic acid (C6H12O2), n-caprylic acid (C8H16O2), lauric acid (C12H24O2), myristic acid (C14H28O2), palmitic acid (C16H32O2), oleic acid (C18H34O2...

  18. Therapeutic targeting of bile acids

    Science.gov (United States)

    Gores, Gregory J.

    2015-01-01

    The first objectives of this article are to review the structure, chemistry, and physiology of bile acids and the types of bile acid malabsorption observed in clinical practice. The second major theme addresses the classical or known properties of bile acids, such as the role of bile acid sequestration in the treatment of hyperlipidemia; the use of ursodeoxycholic acid in therapeutics, from traditional oriental medicine to being, until recently, the drug of choice in cholestatic liver diseases; and the potential for normalizing diverse bowel dysfunctions in irritable bowel syndrome, either by sequestering intraluminal bile acids for diarrhea or by delivering more bile acids to the colon to relieve constipation. The final objective addresses novel concepts and therapeutic opportunities such as the interaction of bile acids and the microbiome to control colonic infections, as in Clostridium difficile-associated colitis, and bile acid targeting of the farnesoid X receptor and G protein-coupled bile acid receptor 1 with consequent effects on energy expenditure, fat metabolism, and glycemic control. PMID:26138466

  19. Synthesis of stearic acid triethanolamine ester over solid acid catalysts

    Institute of Scientific and Technical Information of China (English)

    Tao Geng; Qiu Xiao Li; Ya Jie Jiang; Wei Wang

    2010-01-01

    The synthesis of stearic acid triethanolamine ester over solid acid catalysts was investigated.The results showed that the catalytic activity and selectivity of zirconium sulfate supported on SBA-15(6)(pore diameter 6 nm)is better than that of commonly used hypophosphorous acid,zirconium sulfate supported on MCM-41 and zirconium sulfate supported on SBA-15(9)(pore diameter 9 nm).

  20. Bile acid interactions with cholangiocytes

    Institute of Scientific and Technical Information of China (English)

    Xuefeng Xia; Heather Francis; Shannon Glaser; Gianfranco Alpini; Gene LeSage

    2006-01-01

    Cholangiocytes are exposed to high concentrations of bile acids at their apical membrane. A selective transporter for bile acids, the Apical Sodium Bile Acid Cotransporter (ASBT) (also referred to as Ibat; gene name Slc10a2)is localized on the cholangiocyte apical membrane. On the basolateral membrane, four transport systems have been identified (t-ASBT, multidrug resistance (MDR)3,an unidentified anion exchanger system and organic solute transporter (Ost) heteromeric transporter, OstαOstβ. Together, these transporters unidirectionally move bile acids from ductal bile to the circulation. Bile acids absorbed by cholangiocytes recycle via the peribiliaryplexus back to hepatocytes for re-secretion into bile.This recycling of bile acids between hepatocytes and cholangiocytes is referred to as the cholehepatic shunt pathway. Recent studies suggest that the cholehepatic shunt pathway may contribute in overall hepatobiliary transport of bile acids and to the adaptation to chronic cholestasis due to extrahepatic obstruction. ASBT is acutely regulated by an adenosine 3', 5'-monophosphate (cAMP)-dependent translocation to the apical membrane and by phosphorylation-dependent ubiquitination and proteasome degradation. ASBT is chronically regulated by changes in gene expression in response to biliary bile acid concentration and inflammatory cytokines.Another potential function of cholangiocyte ASBT is to allow cholangiocytes to sample biliary bile acids in order to activate intracellular signaling pathways. Bile acids trigger changes in intracellular calcium, protein kinase C (PKC), phosphoinositide 3-kinase (PI3K), mitogenactivated protein (MAP) kinase and extracellular signalregulated protein kinase (ERK) intracellular signals.Bile acids significantly alter cholangiocyte secretion,proliferation and survival. Different bile acids have differential effects on cholangiocyte intracellular signals,and in some instances trigger opposing effects on cholangiocyte secretion

  1. Molecular Simulation of Naphthenic Acid Removal on Acidic Catalyst Ⅱ. Experimental results of catalytic decarboxylation over acidic catalysts

    Institute of Scientific and Technical Information of China (English)

    Fu Xiaoqin; Tian Songbai; Hou Shuandi; Longjun; Wang Xieqing

    2008-01-01

    The energy barriers of thermal decarboxylation reactions of petroleum acids and catalytic decarboxylation reactions of Br(o)nsted acid and Lewis acid were analyzed using molecular simulation technology.Compared with thermal decarboxylation reactions of petroleum acids, the decarboxylation reactions by acid catalysts were easier to occur. The decarboxylaton effect by Lewis acid was better than Br(o)nsted acid. The mechanisms of catalytic decarboxylation over acid catalyst were also verified by experiments on a fixed bed and a fluidized bed, the experimental results showed that the rate of acid removal could reach up to 97% over the acidic catalyst at a temperature above 400℃.

  2. Kojic acid in organic synthesis

    OpenAIRE

    ZIRAK, MARYAM; Eftekhari-Sis, Bagher

    2015-01-01

    The reactions of kojic acid in organic synthesis are reviewed. The aim of this review is to cover the literature up to the end of 2014, showing the distribution of publications involving kojic acid chemistry in the synthesis of various pyrone containing compounds, pyridine and pyridone heterocycles, and also other organic compounds. First, introductory text about the preparation, biological, and industrial applications, and the chemical properties of kojic acid is given. Then its uses in orga...

  3. Polyunsaturated Fatty Acids in Children

    OpenAIRE

    Lee, Ji-Hyuk

    2013-01-01

    Polyunsaturated fatty acids (PUFAs) are the major components of brain and retina, and are the essential fatty acids with important physiologically active functions. Thus, PUFAs should be provided to children, and are very important in the brain growth and development for fetuses, newborn infants, and children. Omega-3 fatty acids decrease coronary artery disease and improve blood flow. PUFAs have been known to have anti-inflammatory action and improved the chronic inflammation such as auto-im...

  4. Fatty acid biosynthesis in actinomycetes

    OpenAIRE

    Gago, Gabriela; Diacovich, Lautaro; Arabolaza, Ana; Tsai, Shiou-Chuan; Gramajo, Hugo

    2011-01-01

    All organisms that produce fatty acids do so via a repeated cycle of reactions. In mammals and other animals, these reactions are catalyzed by a type I fatty acid synthase (FAS), a large multifunctional protein to which the growing chain is covalently attached. In contrast, most bacteria (and plants) contain a type II system in which each reaction is catalyzed by a discrete protein. The pathway of fatty acid biosynthesis in Escherichia coli is well established and has provided a foundation fo...

  5. [Hydrofluoric acid poisoning: case report].

    Science.gov (United States)

    Cortina, Tatiana Judith; Ferrero, Hilario Andrés

    2013-01-01

    Hydrofluoric acid is a highly dangerous substance with industrial and domestically appliances. Clinical manifestations of poisoning depend on exposure mechanism, acid concentration and exposed tissue penetrability. Gastrointestinal tract symptoms do not correlate with injury severity. Patients with history of hydrofluoric acid ingestion should undergo an endoscopy of the upper gastrointestinal tract. Intoxication requires immediate intervention because systemic toxicity can take place. We present a 5 year old girl who accidentally swallowed 5 ml of 20% hydrofluoric acid. We performed gastrointestinal tract endoscopy post ingestion, which revealed erythematous esophagus and stomach with erosive lesions. Two months later, same study was performed and revealed esophagus and stomach normal mucous membrane.

  6. Preparation and characterization Al3+-bentonite Turen Malang for esterification fatty acid (palmitic acid, oleic acid and linoleic acid)

    Science.gov (United States)

    Abdulloh, Abdulloh; Aminah, Nanik Siti; Triyono, Mudasir, Trisunaryanti, Wega

    2016-03-01

    Catalyst preparation and characterization of Al3+-bentonite for esterification of palmitic acid, oleic acid and linoleic acid has been done. Al3+-bentonite catalyst was prepared from natural bentonite of Turen Malang through cation exchange reaction using AlCl3 solution. The catalysts obtained were characterized by XRD, XRF, pyridine-FTIR and surface area analyser using the BET method. Catalyst activity test of Al3+-bentonite for esterification reaction was done at 65°C using molar ratio of metanol-fatty acid of 30:1 and 0.25 g of Al3+-bentonite catalyst for the period of ½, 1, 2, 3, 4 and 5 hours. Based on the characterization results, the Al3+-bentonite Turen Malang catalyst has a d-spacing of 15.63 Ǻ, acid sites of Brönsted and Lewis respectively of 230.79 µmol/g and 99.39 µmol/g, surface area of 507.3 m2/g and the average of radius pore of 20.09 Å. GC-MS analysis results of the oil phase after esterification reaction showed the formation of biodiesel (FAME: Fatty acid methyl ester), namely methyl palmitate, methyl oleate and methyl linoleate. The number of conversions resulted in esterification reaction using Al3+-bentonite Turen Malang catalyst was 74.61%, 37.75%, and 20, 93% for the esterification of palmitic acid, oleic acid and linoleic acid respectively.

  7. ACETIC ACID AND A BUFFER

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  8. Molecular structural studies of lichen substances II: atranorin, gyrophoric acid, fumarprotocetraric acid, rhizocarpic acid, calycin, pulvinic dilactone and usnic acid

    Science.gov (United States)

    Edwards, Howell G. M.; Newton, Emma M.; Wynn-Williams, David D.

    2003-06-01

    The FT-Raman and infrared vibrational spectra of some important lichen compounds from two metabolic pathways are characterised. Key biomolecular marker bands have been suggested for the spectroscopic identification of atranorin, gyrophoric acid, fumarprotocetraric acid rhizocarpic acid, calycin, pulvinic dilactone and usnic acid. A spectroscopic protocol has been defined for the detection of these molecules in organisms subjected to environmental stresses such as UV-radiation exposure, desiccation and low temperatures. Use of the protocol will be made for the assessment of survival strategies used by stress-tolerant lichens in Antarctic cold deserts.

  9. Peptide Nucleic Acids Having Amino Acid Side Chains

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than the corresponding DNA or RNA strands, and exhibit increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a group consisting of nat...

  10. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    Directory of Open Access Journals (Sweden)

    Je Min Lee

    2016-01-01

    Full Text Available Polyunsaturated fatty acids (PUFAs are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism.

  11. Carbonic Acid Retreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Baylor university

    2003-06-01

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. (1) Solidify the theoretical understanding of the binary CO{sub 2}/H{sub 2}O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. (2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. (3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. (4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. (5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for

  12. Carbonic Acid Pretreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry

    2003-05-31

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic

  13. Amino acids in Arctic aerosols

    Directory of Open Access Journals (Sweden)

    E. Scalabrin

    2012-07-01

    Full Text Available Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS to analyze 20 amino acids to quantify compounds at fmol m−3 levels. Mean total FAA concentration was 1070 fmol m−3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45–60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m−3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (<0.49 μm and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanics.

  14. Ghrelin and gastric acid secretion

    Institute of Scientific and Technical Information of China (English)

    Koji Yakabi; Junichi Kawashima; Shingo Kato

    2008-01-01

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-in-duced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric add secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

  15. Origin of nucleic acids

    International Nuclear Information System (INIS)

    The appearance of nucleic acids is the first event after the birth of membranes which made it possible to assure the perenniality of information. The complexity of these molecules has led some scientists to propose that they were not prebiotic but rather derived a more simple and achiral primitive ancestor. This hypothesis suggests that ribose possesses properties that allowed the formation of certain polysaccharides which evolved to RNA. The first step of the hypothesis is the selection and concentration of ribofuranose. This sugar has chelating properties and its alpha-ribofuranose is favoured in the chelating position. The density of the sugar with a heavy cation is greater than water and thus the complex can escape the UV radiation at the surface of the ocean. The particularity of ribose is to be able to form a homochiral regular array of these basic chelating structures with pyrophosphite. These arrays evolve towards the formation of polysaccharides (poly ribose phosphate) which have a very organized structure. These polysaccharides in turn evolve to RNA by binding of adenine and deoxyguanine which are HCN derivatives that can react with the polysaccharides. The primitive RNA is methylated and oxidized to form prebiotic RNA with adenosine, cytidine, 7methyl-guanosine and ribothymidine as nucleic bases. The pathway of biosynthesis of DNA form RNA will be studied. I suggest that the appearance of DNA results form the interaction between prebiotic double stranded RNA and proteins. DNA could be a product of RNA degradation by proteins. The catabolism of RNA to DNA requires a source of free radicals, protons and hydrides. RNA cannot produce free radicals, which are provided by the phenol group of the amino acid tyrosien. Protons are provided by the medium and hydrides are provided by 7-methyl-guanosine which can fix hydrides coming from hydrogen gas and donate them for the transformation of a riboside to a deoxyriboside. This pathway suggests that DNA appeared at

  16. Folic Acid: Data and Statistics

    Science.gov (United States)

    ... acid fortification in the United States Recently, the American Journal of Preventive Medicine published a new study looking at the costs ... acid fortification and spina bifida in the U.S. American Journal of Preventive Medicine. January 2016 [epub ahead of print]. Related Links ...

  17. Omega-3 fatty acids (image)

    Science.gov (United States)

    Omega-3 fatty acids are a form of polyunsaturated fat that the body derives from food. Omega-3s (and omega- ... fish including tuna, salmon, and mackerel. Other important omega 3 fatty acids are found in dark green leafy vegetables, flaxseed ...

  18. Acid Rain: The Scientific Challenge.

    Science.gov (United States)

    Godfrey, Paul J.

    1991-01-01

    Documents the workings and findings of the Massachusetts Acid Rain Monitoring Project, which has pooled the volunteer efforts of more than 1,000 amateur and professional scientists since 1983. Reports on the origins of air pollution, the prediction of acid rain, and its effects on both water life and land resources. (JJK)

  19. Acid Rain: An Educational Opportunity?

    Science.gov (United States)

    Marion, James I.

    1984-01-01

    Deals with how educators can handle the subject of acid rain; illustrates suggestions with experiences of grade nine students visiting Frost Valley Environmental Education Center (Oliverea, New York) to learn scientific concepts through observation of outdoor phenomena, including a stream; and discusses acid rain, pH levels, and pollution control…

  20. Acid Rain: What's the Forecast?

    Science.gov (United States)

    Bybee, Rodger

    1984-01-01

    Discusses various types of acid rain, considered to be a century-old problem. Topics include: wet and dry deposition, effects on a variety of environments, ecosystems subject to detrimental effects, and possible solutions to the problem. A list of recommended resources on acid rain is provided. (BC)

  1. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2003-01-01

    The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness.......The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness....

  2. Cocrystals of fenamic acids with nicotinamide

    OpenAIRE

    Fábián, László; Hamill, Noel; Eccles, Kevin S; Moynihan, Humphrey A; Maguire, Anita R.; McCausland, Linda; Lawrence, Simon E.

    2011-01-01

    Cocrystal formation between nicotinamide and five fenamic acid derivative drugs (flufenamic acid, niflumic tolfenamic acid, mefenamic acid and meclofenamic acid) was investigated using solution-based and solid-state preparation methods. It was anticipated that the well-known acid-aromatic nitrogen heterosynthon would provide a sufficient driving force for cocrystallization. The experiments yielded cocrystals with four of the five acids. Although the structures of these molecules are similar, ...

  3. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    Directory of Open Access Journals (Sweden)

    B.Syama Sundar

    2014-06-01

    Full Text Available Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation with Mn (VII in case of DL-Mandelic acid. The following order of reactivity is observed: DL-Mandelic acid > Phenyl acetic acid. The high reactivity of DL-Mandelic acid over phenyl acetic acid may be due to different mechanisms operating with the two substrates and benzaldehyde is the final product in both the cases.

  4. N-(3-Nitrophenylmaleamic acid

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-07-01

    Full Text Available In the title compound, C10H8N2O5, the molecule is slightly distorted from planarity. The molecular structure is stabilized by two intramolecular hydrogen bonds. The first is a short O—H...O hydrogen bond (H...O distance = 1.57 Å within the maleamic acid unit and the second is a C—H...O hydrogen bond (H...O distance = 2.24 Å which connects the amide group with the benzene ring. The nitro group is twisted by 6.2 (2° out of the plane of the benzene ring. The crystal structure manifests a variety of hydrogen bonding. The packing is dominated by a strong intermolecular N—H...O interaction which links the molecules into chains running along the b axis. The chains within a plane are further assembled by three additional types of intermolecular C—H...O hydrogen bonds to form a sheet parallel to the (overline{1}01 plane.

  5. Microfluidics in amino acid analysis.

    Science.gov (United States)

    Pumera, Martin

    2007-07-01

    Microfluidic devices have been widely used to derivatize, separate, and detect amino acids employing many different strategies. Virtually zero-dead volume interconnections and fast mass transfer in small volume microchannels enable dramatic increases in on-chip derivatization reaction speed, while only minute amounts of sample and reagent are needed. Due to short channel path, fast subsecond separations can be carried out. With sophisticated miniaturized detectors, the whole analytical process can be integrated on one platform. This article reviews developments of lab-on-chip technology in amino acid analysis, it shows important design features such as sample preconcentration, precolumn and postcolumn amino acid derivatization, and unlabeled and labeled amino acid detection with focus on advanced designs. The review also describes important biomedical and space exploration applications of amino acid analysis on microfluidic devices. PMID:17542043

  6. Molten fatty acid based microemulsions.

    Science.gov (United States)

    Noirjean, Cecile; Testard, Fabienne; Dejugnat, Christophe; Jestin, Jacques; Carriere, David

    2016-06-21

    We show that ternary mixtures of water (polar phase), myristic acid (MA, apolar phase) and cetyltrimethylammonium bromide (CTAB, cationic surfactant) studied above the melting point of myristic acid allow the preparation of microemulsions without adding a salt or a co-surfactant. The combination of SANS, SAXS/WAXS, DSC, and phase diagram determination allows a complete characterization of the structures and interactions between components in the molten fatty acid based microemulsions. For the different structures characterized (microemulsion, lamellar or hexagonal phases), a similar thermal behaviour is observed for all ternary MA/CTAB/water monophasic samples and for binary MA/CTAB mixtures without water: crystalline myristic acid melts at 52 °C, and a thermal transition at 70 °C is assigned to the breaking of hydrogen bounds inside the mixed myristic acid/CTAB complex (being the surfactant film in the ternary system). Water determines the film curvature, hence the structures observed at high temperature, but does not influence the thermal behaviour of the ternary system. Myristic acid is partitioned in two "species" that behave independently: pure myristic acid and myristic acid associated with CTAB to form an equimolar complex that plays the role of the surfactant film. We therefore show that myristic acid plays the role of a solvent (oil) and a co-surfactant allowing the fine tuning of the structure of oil and water mixtures. This solvosurfactant behaviour of long chain fatty acid opens the way for new formulations with a complex structure without the addition of any extra compound. PMID:27241163

  7. Pentadecanoic and Heptadecanoic Acids: Multifaceted Odd-Chain Fatty Acids.

    Science.gov (United States)

    Pfeuffer, Maria; Jaudszus, Anke

    2016-07-01

    The odd-chain fatty acids (OCFAs) pentadecanoic acid (15:0) and heptadecanoic acid (17:0), which account for only a small proportion of total saturated fatty acids in milk fat and ruminant meat, are accepted biomarkers of dairy fat intake. However, they can also be synthesized endogenously, for example, from gut-derived propionic acid (3:0). A number of studies have shown an inverse association between OCFA concentrations in human plasma phospholipids or RBCs and risk of type 2 diabetes and cardiovascular disease. We propose a possible involvement in metabolic regulation from the assumption that there is a link between 15:0 and 17:0 and the metabolism of other short-chain, medium-chain, and longer-chain OCFAs. The OCFAs 15:0 and 17:0 can be elongated to very-long-chain FAs (VLCFAs) such as tricosanoic acid (23:0) and pentacosanoic acid (25:0) in glycosphingolipids, particularly found in brain tissue, or can be derived from these VLCFAs. Their chains can be shortened, yielding propionyl-coenzyme A (CoA). Propionyl-CoA, by succinyl-CoA, can replenish the citric acid cycle (CAC) with anaplerotic intermediates and, thus, improve mitochondrial energy metabolism. Mitochondrial function is compromised in a number of disorders and may be impaired with increasing age. Optimizing anaplerotic intermediate availability for the CAC may help to cope with demands in times of increased metabolic stress and with aging. OCFAs may serve as substrates for synthesis of both odd-numbered VLCFAs and propionyl-CoA or store away excess propionic acid.

  8. Pentadecanoic and Heptadecanoic Acids: Multifaceted Odd-Chain Fatty Acids.

    Science.gov (United States)

    Pfeuffer, Maria; Jaudszus, Anke

    2016-07-01

    The odd-chain fatty acids (OCFAs) pentadecanoic acid (15:0) and heptadecanoic acid (17:0), which account for only a small proportion of total saturated fatty acids in milk fat and ruminant meat, are accepted biomarkers of dairy fat intake. However, they can also be synthesized endogenously, for example, from gut-derived propionic acid (3:0). A number of studies have shown an inverse association between OCFA concentrations in human plasma phospholipids or RBCs and risk of type 2 diabetes and cardiovascular disease. We propose a possible involvement in metabolic regulation from the assumption that there is a link between 15:0 and 17:0 and the metabolism of other short-chain, medium-chain, and longer-chain OCFAs. The OCFAs 15:0 and 17:0 can be elongated to very-long-chain FAs (VLCFAs) such as tricosanoic acid (23:0) and pentacosanoic acid (25:0) in glycosphingolipids, particularly found in brain tissue, or can be derived from these VLCFAs. Their chains can be shortened, yielding propionyl-coenzyme A (CoA). Propionyl-CoA, by succinyl-CoA, can replenish the citric acid cycle (CAC) with anaplerotic intermediates and, thus, improve mitochondrial energy metabolism. Mitochondrial function is compromised in a number of disorders and may be impaired with increasing age. Optimizing anaplerotic intermediate availability for the CAC may help to cope with demands in times of increased metabolic stress and with aging. OCFAs may serve as substrates for synthesis of both odd-numbered VLCFAs and propionyl-CoA or store away excess propionic acid. PMID:27422507

  9. Biophysical properties of phenyl succinic acid derivatised hyaluronic acid

    DEFF Research Database (Denmark)

    Neves-Petersen, Maria Teresa; Klitgaard, Søren; Skovsen, Esben;

    2010-01-01

    Modification of hyaluronic acid (HA) with aryl succinic anhydrides results in new biomedical properties of HA as compared to non-modified HA, such as more efficient skin penetration, stronger binding to the skin, and the ability to blend with hydrophobic materials. In the present study, hyaluronic...... acid has been derivatised with the anhydride form of phenyl succinic acid (PheSA). The fluorescence of PheSA was efficiently quenched by the HA matrix. HA also acted as a singlet oxygen scavenger. Fluorescence lifetime(s) of PheSA in solution and when attached to the HA matrix has been monitored...

  10. Hypocholesterolemic Effects of Eicosapentaenoic Acid and Docosahexaenoic Acid in Rats

    OpenAIRE

    KANAZAWA, Akio; TESHIMA, Shin-ichi; TOKIWA, Shigeru; IMATANAKA, Nobuya; カナザワ, アキオ; テシマ, シンイチ; トキワ, シゲル; イマタナカ, ノブヤ; 金沢, 昭夫; 手島, 新一; 常盤, 繁; 今田中, 伸哉

    1984-01-01

    Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) methylesters (ME) were preparedfrom a squid-liver oil and their hypocholesterolemic activities examined with rats. The supplementof 0.3% EPA-ME to the diet containing 1.0% cholesterol and 4.0% butter as lipids reduced a serum-cholesterollevel markedly, whereas DHA-ME gave almost no effect on the serum-cholesterol level.Both EPA-ME and DHA-ME reduced the liver-cholesterol level as effectively as linoleic acid did.The supplement of smal...

  11. Analytical application of aminohydroxamic acids

    International Nuclear Information System (INIS)

    Anthranilic hydroxamic acid was prepared by coupling of methylanthranilate (prepared by esterification of anthranilic acid with methyl alcohol using the fisher-speir method) with freshly prepared hydroxylamine. The lignad was characterized by the usual reaction of hydroxamic acid with acidic V(V) and Fe(III) solutions that gives blood-red colour in amyl alcohol and deep-violet colour in aqueous solution, respectively. The absorbance of Fe(III)-hydroxamic acids complexes increases with increase of pH. In this study, the effect of pH on the absorbance of Fe(III)-anthranilic hydroxamic acid was in accordance with this trend. The maximum absorbance was obtained at pH 5.0 at maximum wavelength of 482 nm. For Cu(II)-anthranilic hydroxamic acid complex, the use of acidic basic pH lead to precipitation of Cu(II)-ligand complex. But when using buffer pH (acetic acid/sodium acetate) a clear green colour of Cu(II)-ligand complex was obtained. The maximum wavelength of 390 nm. V(V)-anthranilic hydroxamic acid complex was extracted in acidic medium in amyl alcohol at pH 2.0 because in aqueous solution V(V)-anthranilic hydroxamic acid complex has not clear colour. It was observed the the maximum extraction in acidic medium decrease sharply with the increasing of pH value. The maximum wavelength for maximum absorbance was recorded at 472 nm. V(V) interfered with determination of Fe(III)) above concentration of 2 ppm, whereas Cu(II) interferes slightly with the determination of Fe(III) ions even at a high concentration of the Cu(II) ions. Both Cu(II) and Ni(II) do not interfere with the determination of V(V) ions even at high concentrations, Fe(III) ion produced slight interference, while Mo(VI) ions have a pronounced interference. Both V(V) and Fe(III) ions interfered markedly with the determination of Cu(II) ions, and made impractical under conditions. However, the calibration curves for the three metal ions produced a practical linear dynamic range.(Author)

  12. Listeria monocytogenes DNA glycosylase AdiP affects flagellar motility, biofilm formation, virulence, and stress responses

    Science.gov (United States)

    The temperature-dependent alteration of flagellar motility gene expression is critical for the foodborne pathogen Listeria monocytogenes to respond to a changing environment. In this study, a genetic determinant, L. monocytogenes f2365_0220 (lmof2365_0220), encoding a putative protein that is struct...

  13. Polymeric chains, hydrogen bonds and magnetism in Nd(III) adipates

    International Nuclear Information System (INIS)

    An AC susceptibility study of [Nd2(O2C(CH2)4CO2)3(H2O)2] (1) obtained from a solution at ambient conditions was performed in the range 14-320K. An ordering transition, TC=280(2)K, not related to a structural phase transition, a ferromagnetic like Curie-Weiss behavior above TC, an antiferromagnetic like dependence of χ'-1 at the lowest temperatures and a non-linear thermal dependence of χ'-1 in the in-between region have been observed. Samples prepared by hydration of 1 during different periods showed enhancement of the observed features. Links between water content, crystal structure and magnetic response are discussed

  14. The Property and Application of Arachidonic Acid

    Institute of Scientific and Technical Information of China (English)

    王相勤; 姚建铭; 袁成凌; 王纪; 余增亮

    2002-01-01

    Arachidonic acid (AA) is one of the most important PUFAs (polyunsaturated fatty acids) in human body. A high-yield arachidonic acid-producing strain (mortierella alpina) was selected by ion implantation (the relative content of arachidonic acid is 70.2% among all fatty acids). This paper mainly introduced the structure, distribution, source, physiologic healthcare function and application of AA.

  15. Cycloadditions for Studying Nucleic Acids.

    Science.gov (United States)

    Kath-Schorr, Stephanie

    2016-02-01

    Cycloaddition reactions for site-specific or global modification of nucleic acids have enabled the preparation of a plethora of previously inaccessible DNA and RNA constructs for structural and functional studies on naturally occurring nucleic acids, the assembly of nucleic acid nanostructures, therapeutic applications, and recently, the development of novel aptamers. In this chapter, recent progress in nucleic acid functionalization via a range of different cycloaddition (click) chemistries is presented. At first, cycloaddition/click chemistries already used for modifying nucleic acids are summarized, ranging from the well-established copper(I)-catalyzed alkyne-azide cycloaddition reaction to copper free methods, such as the strain-promoted azide-alkyne cycloaddition, tetrazole-based photoclick chemistry and the inverse electron demand Diels-Alder cycloaddition reaction between strained alkenes and tetrazine derivatives. The subsequent sections contain selected applications of nucleic acid functionalization via click chemistry; in particular, site-specific enzymatic labeling in vitro, either via DNA and RNA recognizing enzymes or by introducing unnatural base pairs modified for click reactions. Further sections report recent progress in metabolic labeling and fluorescent detection of DNA and RNA synthesis in vivo, click nucleic acid ligation, click chemistry in nanostructure assembly and click-SELEX as a novel method for the selection of aptamers. PMID:27572987

  16. PHARMACOLOGICAL ACTIVITIES OF PROTOCATECHUIC ACID.

    Science.gov (United States)

    Khan, Abida Kalsoom; Rashid, Rehana; Fatima, Nighat; Mahmood, Sadaf; Mir, Sadullah; Khan, Sara; Jabeen, Nyla; Murtaza, Ghulam

    2015-01-01

    Protocatechuic acid (3,4-dihydroxybenzoic acid, PCA) is a simple phenolic acid. It is found in a large variety of edible plants and possesses various pharmacological activities. This article aims to review the modern trends in phytochemical isolation and extraction of PCA from plants and other natural resources. Moreover, this article also encompasses pharmacological and biological activities of PCA. It is well known to have anti-inflammatory, antioxidant, anti-hyperglycemia, antibacterial, anticancer, anti-ageing, anti-athro- genic, anti-tumoral, anti-asthma, antiulcer, antispasmodic and neurological properties. PMID:26647619

  17. Amino Acids from a Comet

    Science.gov (United States)

    Cook, Jamie Elisla

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

  18. Molar extinction coefficients of some fatty acids

    Science.gov (United States)

    Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

    2002-10-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

  19. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    Directory of Open Access Journals (Sweden)

    NEENA GARG

    2015-10-01

    Full Text Available Lactic acid bacteria (LAB is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LAB are used as starter culture, consortium members and bioprotective agents in food industry that improve food quality, safety and shelf life. A variety of probiotic LAB species are available including Lactobacillus acidophilus, L. bulgaricus, L. lactis, L. plantarum, L. rhamnosus, L. reuteri, L. fermentum, Bifidobacterium longum, B. breve, B. bifidum, B. esselnsis, B. lactis, B. infantis that are currently recommended for development of functional food products with health-promoting capacities.

  20. Uranium extraction from phosphoric acid

    International Nuclear Information System (INIS)

    A study has been carried out for the extraction of uranium from phosphoric acid produced in Algeria. First of all, the Algerian phosphoric acid produced in Algeria by SONATRACH has been characterised. This study helped us to synthesize a phosphoric acid that enabled us to pass from laboratory tests to pilot scale tests. We have then examined extraction and stripping parameters: diluent, DZEPHA/TOPO ratio and oxidising agent. The laboratory experiments enabled us to set the optimum condition for the choice of diluent, extractant concentration, ratio of the synergic mixture, oxidant concentration, redox potential. The equilibrium isotherms lead to the determination of the number of theoretical stages for the uranium extraction and stripping of uranium, then the extraction from phosphoric acid has been verified on a pilot scale (using a mixer-settler)

  1. Biotechnological production of citric acid

    Directory of Open Access Journals (Sweden)

    Belén Max

    2010-12-01

    Full Text Available This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors. Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus. Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger, and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks for the bioproduction of citric acid.

  2. Pantothenic acid (Vitamin B5)

    Science.gov (United States)

    ... It is widely found in both plants and animals including meat, vegetables, cereal grains, legumes, eggs, and ... vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin/niacinamide), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), ...

  3. Low acid producing solid propellants

    Science.gov (United States)

    Bennett, Robert R.

    1995-01-01

    The potential environmental effects of the exhaust products of conventional rocket propellants have been assessed by various groups. Areas of concern have included stratospheric ozone, acid rain, toxicity, air quality and global warming. Some of the studies which have been performed on this subject have concluded that while the impacts of rocket use are extremely small, there are propellant development options which have the potential to reduce those impacts even further. This paper discusses the various solid propellant options which have been proposed as being more environmentally benign than current systems by reducing HCI emissions. These options include acid neutralized, acid scavenged, and nonchlorine propellants. An assessment of the acid reducing potential and the viability of each of these options is made, based on current information. Such an assessment is needed in order to judge whether the potential improvements justify the expenditures of developing the new propellant systems.

  4. Bile acid sequestrants for cholesterol

    Science.gov (United States)

    ... ency/patientinstructions/000787.htm Bile acid sequestrants for cholesterol To use the sharing features on this page, ... are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can stick ...

  5. Simultaneous analysis of small organic acids and humic acids using high performance size exclusion chromatography

    NARCIS (Netherlands)

    Qin, X.P.; Liu, F.; Wang, G.C.; Weng, L.P.

    2012-01-01

    An accurate and fast method for simultaneous determination of small organic acids and much larger humic acids was developed using high performance size exclusion chromatography. Two small organic acids, i.e. salicylic acid and 2,3-dihydroxybenzoic acid, and one purified humic acid material were used

  6. Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Kessel, Kurt R.

    2016-01-01

    Corrosion is an extensive problem that affects the National Aeronautics and Space Administration (NASA) and European Space Agency (ESA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. It is vital to reduce corrosion costs and risks in a sustainable manner. The primary objective of this effort is to qualify citric acid as an environmentally-preferable alternative to nitric acid for passivation of stainless steel alloys.

  7. Aqueous Photochemistry of Glyoxylic Acid.

    Science.gov (United States)

    Eugene, Alexis J; Xia, Sha-Sha; Guzman, Marcelo I

    2016-06-01

    Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging of photoproducts is studied by UV-visible and fluorescence spectroscopies to reveal that the optical properties are altered by the glyoxal produced. The optical properties display periodicity in the time domain of the UV-visible spectrum of chromophores with absorption enhancement (thermochromism) or loss (photobleaching) during nighttime and daytime cycles, respectively. During irradiation, excited state glyoxylic acid can undergo α-cleavage or participate in hydrogen abstractions. The use of (13)C nuclear magnetic resonance spectroscopy (NMR) analysis shows that glyoxal is an important intermediate produced during direct photolysis. Glyoxal quickly reaches a quasi-steady state as confirmed by UHPLC-MS analysis of its corresponding (E) and (Z) 2,4-dinitrophenylhydrazones. The homolytic cleavage of glyoxylic acid is proposed as a fundamental step for the production of glyoxal. Both carbon oxides, CO2(g) and CO(g) evolving to the gas-phase, are quantified by FTIR spectroscopy. Finally, formic acid, oxalic acid, and tartaric acid photoproducts are identified by ion chromatography (IC) with conductivity and electrospray (ESI) mass spectrometry (MS) detection and (1)H NMR spectroscopy. A reaction mechanism is proposed based on all experimental observations. PMID:27192089

  8. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B;

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

  9. SATURATED PICRIC ACID PREVENTS AUTOPHAGIA

    Directory of Open Access Journals (Sweden)

    V Rahimi-Movaghar

    2008-08-01

    Full Text Available "nThe dysesthesia and paresthesia that occurs in laboratory rats after spinal cord injury (SCI results in autophagia. This self-destructive behavior interferes with functional assessments in designed studies and jeopardizes the health of the injured rat. In this study, we evaluated role of saturated picric acid in the prevention of autophagia and self-mutilation. All rats were anesthetized with an intraperitoneal injection of a mixture of ketamine (100 mg/kg and xylazine (10 mg/kg for the SCI procedures. In the first 39 rats, no solution applied to the hind limbs, but in the next 26 cases, we smeared the saturated picric acid on the tail, lower extremities, pelvic, and abdomen of the rats immediately after SCI. In the rats without picric acid, 23 rats died following autophagia, but in the 26 rats with picric acid, there was no autophagia (P < 0.001. Picric acid side effects in skin and gastrointestinal signs such as irritation, redness and diarrhea were not seen in any rat. Saturated picric acid is a topical solution that if used appropriately and carefully, might be safe and effectively prevents autophagia and self-mutilation. When the solution is applied to the lower abdomen and limbs, we presume that its bitterness effectively prevents the rat from licking and biting the limb.

  10. Performance of Different Acids on Sandstone Formations

    Directory of Open Access Journals (Sweden)

    M. A. Zaman

    2013-12-01

    Full Text Available Stimulation of sandstone formations is a challenging task, which involves several chemicals and physical interactions of the acid with the formation. Some of these reactions may result in formation damage. Mud acid has been successfully used to stimulate sandstone reservoirs for a number of years. It is a mixture of hydrofluoric (HF and hydrochloric (HCl acids designed to dissolve clays and siliceous fines accumulated in the near-wellbore region. Matrix acidizing may also be used to increase formation permeability in undamaged wells. The change may be up to 50% to 100% with the mud acid. For any acidizing process, the selection of acid (Formulation and Concentration and the design (Pre-flush, Main Acid, After-flush is very important. Different researchers are using different combinations of acids with different concentrations to get the best results for acidization. Mainly the common practice is combination of Hydrochloric Acid – Hydrofluoric with Concentration (3% HF – 12% HCl. This paper presents the results of a laboratory investigation of Orthophosphoric acid instead of hydrochloric acid in one combination and the second combination is Fluoboric and formic acid and the third one is formic and hydrofluoric acid. The results are compared with the mud acid and the results calculated are porosity, permeability, and FESEM Analysis and Strength tests. All of these new combinations shows that these have the potential to be used as acidizing acids on sandstone formations.

  11. An Efficient Procedure for Esterification of Aryloxyacetic Acid and Arylthioacetic Acid Catalyzed by Silica Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    LI,Hong-Ya; LI,Ji-Tai; LI,Hui-Zhang

    2004-01-01

    @@ Aryloxyacetate and arylthioacetate are wildly used in herbicides, plant regulator and insecticides. Recently, Wille et al. have reported that methyl aryloxyacetate is an efficient agent to prevent and treat allergic contact dermatitis.[1] The most popular synthesis is by heating sodium phenoxide (mercaptide) with ethyl chloroacetate in DMF,[2] or by the esterification of acid with alcohol using concentrated H2SO4 as catalyst.[3] In this paper, synthesis of aryloxyacetate and aryl thioacetate from aryloxyacetic acid and arylthioacetic acid respectively in ether catalyzed by silica sulfuric acid in 83%~94% yields is described. The catalyst is reused for 3 times without significant loss of activity (Entry 4). Compared with common procedures, the present procedure possesses the advantages of the operational simplicity, short reaction time,less-corrosion, high yield and reusable catalyst.

  12. Vanadocene reactions with hydroxy acids. [Hydroxy acids: acetylsalicylic, gallic, lactic, salicyclic, orotic,. gamma. -hydroxybutyric acids

    Energy Technology Data Exchange (ETDEWEB)

    Latyaeva, V.N.; Lineva, A.N.; Zimina, S.V.; Ehllert, O.G.; Arsen' eva, T.I. (Gor' kovskij Meditsinskij Inst. (USSR))

    1984-03-01

    To prepare a series of vanadium cyclopentadienylcarboxylates soluble in water, the vanadocene reactions with lactic, ..gamma..-oxybutyric-, salicylic,- gallic-, orotic-, and acetylsalicylic acids have been studied. To determine the influence of cyclopentadienyl groups, bound with a vanadium atom, on the physiological activity of the complexes formed, vanadium halides are made to react with lactic acid. Only the vanadocene reaction with orotic acid was conducted in an aqueous medium, other interactions were realized in the diethyl ether, toluene, T, H, P medium. The interaction of vanadocene and vanadium halides with lactic-, salicylic-, acetylsalicylic- and gallic acids was found to lead to the formation of water-soluble vanadium complexes of Cp/sub 2/, VOCOR or CpV (OCOR)/sub 2/ type. The data on the produced compounds yield, their IR spectra, decomposition temperatures, solubility, effective magnetic moments are presented.

  13. Fluorotelomer acids are more toxic than perfluorinated acids.

    Science.gov (United States)

    Phillips, Michelle M MacDonald; Dinglasan-Panlilio, Mary Joyce A; Mabury, Scott A; Solomon, Keith R; Sibley, Paul K

    2007-10-15

    Saturated and unsaturated fluorotelomer carboxylic acids have been identified as intermediates in the degradation of fluorotelomer alcohols to perfluorinated carboxylic acids (PFCAs). Although surface waters are the likely environmental sink for telomer acids, no fate or toxicity data exist for this matrix. We assessed the acute toxicity of the 4:2, 6:2, 8:2, and 10:2 saturated (FTCA) and unsaturated (FTUCA) fluorotelomer carboxylic acids to Daphnia magna, Chironomus tentans, and Lemna gibba. In general, toxicity increased with increasing fluorocarbon (FC) chain length, particularly for telomer acids of > or =8 FCs. In addition, the FTCAs were generally more toxic than the corresponding FTUCAs. Acute EC50s ranged from 0.025 mg/L (0.04 micromol/L) for D. magna (10:2 FTCA, immobility) to 63 mg/L (167 micromol/L) for C. tentans (6:2 FTCA, growth). While chain-length trends observed in the current study agree with those previously reported for PFCAs, the toxicity thresholds generated here are up to 10,000 times smaller. Our data provide the first evidence that PFCA precursors are more toxic than the PFCAs themselves. PMID:17993163

  14. Nucleic Acid Backbone Structure Variations: Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    Nielsen, Peter E.

    2010-01-01

    Synthetic analogues and mimics of the natural genetic material deoxyribonucleic acid (DNA) are potential gene therapeutic (antisense or antigene) drugs. One of these mimics, peptide nucleic acids (PNAs), are chemically closer to peptides and proteins than to DNA, but nonetheless have retained many...... of the structural properties of DNA. These molecules have found applications as probes in genetic diagnostics and are also being developed into antisense (RNA (ribonucleic acid) interference) gene therapeutic drugs, targeting selected genes through sequence-specific recognition of (messenger or micro......)RNA and in the future also antigene applications targeting the double-stranded DNA of the genes themselves leading to gene silencing or guiding specific gene repair. Finally, the special chemical and structural properties of PNA suggest that these or similar molecules might have played a role in the prebiotic origin...

  15. Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

    Science.gov (United States)

    Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

    2006-01-01

    Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

  16. Boronic acid-based autoligation of nucleic acids

    DEFF Research Database (Denmark)

    Barbeyron, R.; Vasseur, J.-J.; Smietana, M.;

    2013-01-01

    Abstract: The development of synthetic systems displaying dynamic and adaptive characteristics is a formidable challenge with wide applications from biotechnology to therapeutics. Recently, we described a dynamic and programmable nucleic acid-based system relying on the formation of reversible...... boronate internucleosidic linkages. The DNA- or RNA-templated system comprises a 5′-ended boronic acid probe connecting a 3′-ended ribonucleosidic oligonucleotide partner. To explore the dominant factors that control the reversible linkage, we synthesized a series of 3′-end modified ribonucleotidic strands...

  17. Conjugated Linoleic Acid Accumulation via 10-Hydroxy-12-Octadecaenoic Acid during Microaerobic Transformation of Linoleic Acid by Lactobacillus acidophilus

    OpenAIRE

    Ogawa, Jun; Matsumura, Kenji; Kishino, Shigenobu; Omura, Yoriko; Shimizu, Sakayu

    2001-01-01

    Specific isomers of conjugated linoleic acid (CLA), a fatty acid with potentially beneficial physiological and anticarcinogenic effects, were efficiently produced from linoleic acid by washed cells of Lactobacillus acidophilus AKU 1137 under microaerobic conditions, and the metabolic pathway of CLA production from linoleic acid is explained for the first time. The CLA isomers produced were identified as cis-9, trans-11- or trans-9, cis-11-octadecadienoic acid and trans-9, trans-11-octadecadie...

  18. 21 CFR 184.1007 - Aconitic acid.

    Science.gov (United States)

    2010-04-01

    ... salt from cane sugar or molasses. It may be synthesized by sulfuric acid dehydration of citric acid.... 102-103, test for citric acid, which is incorporated by reference in accordance with 5 U.S.C. 552(a... carbonizable substances. Passes the test for citric acid of the “Food Chemicals Codex,” 4th ed. (1996), pp....

  19. How does Listeria monocytogenes combat acid conditions?

    Science.gov (United States)

    Listeria monocytogenes, a major foodborne pathogen, possesses a number of mechanisms which enable it to combat the challenges posed by acidic environments such as acidic foods and the acidity in the gastrointestinal tract. These mechanisms include the acid tolerance response, a two-component regula...

  20. Veal fatty acid composition of different breeds

    OpenAIRE

    Ivica Kos; Jelena Ramljak; Ante Ivanković; Miljenko Konjačić; Nikolina Kelava

    2010-01-01

    Veal fatty acid composition in M. Longissimus thoracis was investigated in different calf breeds (Simmental, Holstein, Simmental x Holstein). Calves were reared on the same farm under identical feeding and handling conditions. Simmental calves had higher polyunsaturated fatty acid (PUFA) but lower saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) values than Holstein and crossbreed calves (P

  1. Effect of propionic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    Science.gov (United States)

    Xu, Jian; Bao, Jia-Wei; Su, Xian-Feng; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2016-03-01

    In this study, an integrated citric acid-methane fermentation process was established to solve the problem of wastewater treatment in citric acid production. Citric acid wastewater was treated through anaerobic digestion and then the anaerobic digestion effluent (ADE) was further treated and recycled for the next batch citric acid fermentation. This process could eliminate wastewater discharge and reduce water resource consumption. Propionic acid was found in the ADE and its concentration continually increased in recycling. Effect of propionic acid on citric acid fermentation was investigated, and results indicated that influence of propionic acid on citric acid fermentation was contributed to the undissociated form. Citric acid fermentation was inhibited when the concentration of propionic acid was above 2, 4, and 6 mM in initial pH 4.0, 4.5 and, 5.0, respectively. However, low concentration of propionic acid could promote isomaltase activity which converted more isomaltose to available sugar, thereby increasing citric acid production. High concentration of propionic acid could influence the vitality of cell and prolong the lag phase, causing large amount of glucose still remaining in medium at the end of fermentation and decreasing citric acid production.

  2. [Circulating nucleic acids and infertility].

    Science.gov (United States)

    Scalici, E; Mullet, T; Ferrières Hoa, A; Gala, A; Loup, V; Anahory, T; Belloc, S; Hamamah, S

    2015-09-01

    Circulating nucleic acids (cell-free DNA and microRNAs) have for particularity to be easily detectable in the biological fluids of the body. Therefore, they constitute biomarkers of interest in female and male infertility care. Indeed, in female, they can be used to detect ovarian reserve disorders (polycystic ovary syndrome and low functional ovarian reserve) as well as to assess follicular microenvironment quality. Moreover, in men, their expression levels can vary in case of spermatogenesis abnormalities. Finally, circulating nucleic acids have also the ability to predict successfully the quality of in vitro embryo development. Their multiple contributions during assisted reproductive technology (ART) make of them biomarkers of interest, for the development of new diagnostic and/or prognostic tests, applied to our specialty. Circulating nucleic acids would so offer the possibility of personalized medical care for infertile couples in ART. PMID:26298813

  3. Toxicologic Study of Monochloroacetic Acid

    Institute of Scientific and Technical Information of China (English)

    Lu Bo; Zhan Ping

    2006-01-01

    @@ Monochloroacetic Acid (MCA) is a chlorinated analog of acetic acids. MCA and its sodium salt (SMCA) are widely used as a chemical intermediate (primarily in the manufacture of chlorophenoxy herbicides,carboxymethylcelluose, glycine and indigoid dyes).Moreover, MCA has been found as a common by-product of the chlorination of drinking water. Chloroacetates are ubiquitous in the environment, and MCA is the most abundant among chloroacetates. A background level of 0.1 - 1μg/L is expected to occur in precipitation[1]. Total world wide annual production of MCA reported was about 400 000 tons[2]. Many studies have showed that MCA not only caused acute or chronic damage to the skin , liver, kidney, heart, brain and other organs, but also caused acute death systemically under high concentration[2,3]. So this article will discuss the toxic effect of Monochloroacetic Acid in Toxicology.

  4. Nitric Acid Poisoning: Case Report

    International Nuclear Information System (INIS)

    Nitric acid (HNO3) is a corrosive fluid that, when in contact with reducing agents, generates nitrogen oxides that are responsible for inhalation poisoning. We present two cases of poisoning from nitric acid gas inhalation resulting from occupational exposure. Imaging findings were similar in both cases, consistent with adult respiratory distress syndrome (ARDS): bilaterally diffuse alveolar opacities on the chest X-ray and a cobblestone pattern on computed tomography (CT).one of the patients died while the other evolved satisfactorily after treatment with n-acetyl cysteine and mechanical ventilation. The diagnosis of nitric acid poisoning was made on the basis of the history of exposure and the way in which the radiological findings evolved.

  5. Fauna of an acid stream

    Energy Technology Data Exchange (ETDEWEB)

    Jewell, M.E.

    1922-01-01

    The hydrogen-ion concentration of the water of the big muddy river was found to vary between pH 5.8 and pH 6.8 to 7.2, the higher acidity occurring during the winter. The bottom fauna was characterized by the abundance of clams and shrimp, and by the absence of branchiate snails and ephemerid nymphs. Fish fry and fingerlings were found in large numbers during the summer in weakly acid water, pH 6.8. Observations on our acid streams, continued over a considerable period of time, would tell us much concerning the adaptability of various species to different hydrogen-ion concentrations and are greatly needed in the interpretation of experimental data.

  6. Tumor Acidity as Evolutionary Spite

    Directory of Open Access Journals (Sweden)

    Mohammed E. A. Shayoub

    2011-01-01

    Full Text Available Most cancer cells shift their metabolic pathway from a metabolism reflecting the Pasteur-effect into one reflecting the Warburg-effect. This shift creates an acidic microenvironment around the tumor and becomes the driving force for a positive carcinogenesis feedback loop. As a consequence of tumor acidity, the tumor microenvironment encourages a selection of certain cell phenotypes that are able to survive in this caustic environment to the detriment of other cell types. This selection can be described by a process which can be modeled upon spite: the tumor cells reduce their own fitness by making an acidic environment, but this reduces the fitness of their competitors to an even greater extent. Moreover, the environment is an important dimension that further drives this spite process. Thus, diminishing the selective environment most probably interferes with the spite process. Such interference has been recently utilized in cancer treatment.

  7. Tumor Acidity as Evolutionary Spite

    Energy Technology Data Exchange (ETDEWEB)

    Alfarouk, Khalid O., E-mail: khalid.alfarouk@act.sd [Department of Biotechnology, Africa City of Technology, Khartoum (Sudan); Department of Pharmaceutics, Faculty of Pharmacy, University of Khartoum, Khartoum (Sudan); Muddathir, Abdel Khalig [Department of Pharmacognosy, Faculty of Pharmacy, University of Khartoum, Khartoum (Sudan); Shayoub, Mohammed E. A. [Department of Pharmaceutics, Faculty of Pharmacy, University of Khartoum, Khartoum (Sudan)

    2011-01-20

    Most cancer cells shift their metabolic pathway from a metabolism reflecting the Pasteur-effect into one reflecting the Warburg-effect. This shift creates an acidic microenvironment around the tumor and becomes the driving force for a positive carcinogenesis feedback loop. As a consequence of tumor acidity, the tumor microenvironment encourages a selection of certain cell phenotypes that are able to survive in this caustic environment to the detriment of other cell types. This selection can be described by a process which can be modeled upon spite: the tumor cells reduce their own fitness by making an acidic environment, but this reduces the fitness of their competitors to an even greater extent. Moreover, the environment is an important dimension that further drives this spite process. Thus, diminishing the selective environment most probably interferes with the spite process. Such interference has been recently utilized in cancer treatment.

  8. Influence of acidified acidity to uranium bioleaching

    International Nuclear Information System (INIS)

    The relationship between the acidified acidity and the acid consumption and uranium leaching rate in the process of uranium bioleaching is investigated. Results indicate that higher uranium leaching rate is obtained when the relatively high acidity was applied at beginning. For different minerals, although the original acidity should be different, lower original acidity was not better for shortening leaching period and improving uranium leaching rate. It confirms 30-40 g/L sulfuric acid as the original acidity was more suitable and more than 30 g/ L should be applied if the mineral particle sizes were larger. (authors)

  9. Solubilities of Isophthalic Acid in Acetic Acid + Water Solvent Mixtures

    Institute of Scientific and Technical Information of China (English)

    CHENG Youwei; HUO Lei; LI Xi

    2013-01-01

    The solubilities of isophthalic acid (1) in binary acetic acid (2) + water (3) solvent mixtures were determined in a pressurized vessel.The temperature range was from 373.2 to 473.2K and the range of the mole fraction of acetic acid in the solvent mixtures was from x2 =0 to 1.A new method to measure the solubility was developed,which solved the problem of sampling at high temperature.The experimental results indicated that within the temperature range studied,the solubilities of isophthalic acid in all mixtures showed an increasing trend with increasing temperature.The experimental solubilities were correlated by the Buchowski equation,and the calculate results showed good agreement with the experimental solubilities.Furthermore,the mixed solvent systems were found to exhibit a maximum solubility effect on the solubility,which may be attributed to the intermolecular association between the solute and the solvent mixture.The maximum solubility effect was well modeled by the modified Wilson equation.

  10. Bipolar lead acid battery development

    Science.gov (United States)

    Eskra, Michael; Vidas, Robin; Miles, Ronald; Halpert, Gerald; Attia, Alan; Perrone, David

    1991-01-01

    A modular bipolar battery configuration is under development at Johnson Control, Inc. (JCI) and the Jet Propulsion Laboratory (JPL). The battery design, incorporating proven lead acid electrochemistry, yields a rechargeable, high-power source that is light weight and compact. This configuration offers advantages in power capability, weight, and volume over conventional monopolar batteries and other battery chemistries. The lead acid bipolar battery operates in a sealed, maintenance-free mode allowing for maximum application flexibility. It is ideal for high-voltage and high-power applications.

  11. Nucleic Acid Aptamers Against Proteases

    DEFF Research Database (Denmark)

    Dupont, D M; Andersen, L M; Bøtkjær, Kenneth Alrø;

    2011-01-01

    Proteases are potential or realized therapeutic targets in a wide variety of pathological conditions. Moreover, proteases are classical subjects for studies of enzymatic and regulatory mechanisms. We here review the literature on nucleic acid aptamers selected with proteases as targets. Designing......-specifically, for instance with vastly different affinities to zymogen and active enzyme forms. Furthermore, aptamers can be selected to inhibit the enzyme activity of the target proteases, but also to inhibit functionally important exosite interactions, for instance cofactor binding. Several protease-inhibiting aptamers...... strategies and of new principles for regulating the activity of the inhibitory action of aptamers of general interest to researchers working with nucleic acid aptamers...

  12. Acid Sulfate Alteration on Mars

    Science.gov (United States)

    Ming, D. W.; Morris, R. V.

    2016-01-01

    A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Acid sulfate alteration has been identified at all three landing sites visited by NASA rover missions (Spirit, Opportunity, and Curiosity). Spirit landed in Gusev crater in 2004 and discovered Fe-sulfates and materials that have been extensively leached by acid sulfate solutions. Opportunity landing on the plains of Meridiani Planum also in 2004 where the rover encountered large abundances of jarosite and hematite in sedimentary rocks. Curiosity landed in Gale crater in 2012 and has characterized fluvial, deltaic, and lacustrine sediments. Jarosite and hematite were discovered in some of the lacustrine sediments. The high elemental abundance of sulfur in surface materials is obvious evidence that sulfate has played a major role in aqueous processes at all landing sites on Mars. The sulfate-rich outcrop at Meridiani Planum has an SO3 content of up to 25 wt.%. The interiors of rocks and outcrops on the Columbia Hills within Gusev crater have up to 8 wt.% SO3. Soils at both sites generally have between 5 to 14 wt.% SO3, and several soils in Gusev crater contain around 30 wt.% SO3. After normalization of major element compositions to a SO3-free basis, the bulk compositions of these materials are basaltic, with a few exceptions in Gusev crater and in lacustrine mudstones in Gale crater. These observations suggest that materials encountered by the rovers were derived from basaltic precursors by acid sulfate alteration under nearly isochemical conditions (i.e., minimal leaching). There are several cases, however, where acid sulfate alteration minerals (jarosite and hematite) formed in open hydrologic systems, e.g., in Gale crater lacustrine mudstones. Several hypotheses have been suggested for the

  13. 21 CFR 184.1033 - Citric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Citric acid. 184.1033 Section 184.1033 Food and... Substances Affirmed as GRAS § 184.1033 Citric acid. (a) Citric acid (C6H8O7, CAS Reg. No. 77-92-9) is the... mole of water per mole of citric acid. Citric acid may be produced by recovery from sources such...

  14. General consideration on sialic acid chemistry.

    Science.gov (United States)

    Cao, Hongzhi; Chen, Xi

    2012-01-01

    Sialic acids, also known as neuraminic acids, are a family of negatively charged α-keto acids with a nine-carbon backbone. These unique sugars have been found at the termini of many glycan chains of vertebrate cell surface, which play pivotal roles in mediating or modulating a variety of physiological and pathological processes. This brief review covers general approaches for synthesizing sialic acid containing structures. Recently developed synthetic methods along with structural diversities and biological functions of sialic acid are discussed.

  15. Acid-functionalized polyolefin materials and their use in acid-promoted chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Oyola, Yatsandra; Tian, Chengcheng; Bauer, John Christopher; Dai, Sheng

    2016-06-07

    An acid-functionalized polyolefin material that can be used as an acid catalyst in a wide range of acid-promoted chemical reactions, wherein the acid-functionalized polyolefin material includes a polyolefin backbone on which acid groups are appended. Also described is a method for the preparation of the acid catalyst in which a precursor polyolefin is subjected to ionizing radiation (e.g., electron beam irradiation) of sufficient power and the irradiated precursor polyolefin reacted with at least one vinyl monomer having an acid group thereon. Further described is a method for conducting an acid-promoted chemical reaction, wherein an acid-reactive organic precursor is contacted in liquid form with a solid heterogeneous acid catalyst comprising a polyolefin backbone of at least 1 micron in one dimension and having carboxylic acid groups and either sulfonic acid or phosphoric acid groups appended thereto.

  16. Citric Acid Passivation of Stainless Steel

    Science.gov (United States)

    Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

    2009-01-01

    Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

  17. [Alpha-linolenic acid and cardiovascular diseases].

    Science.gov (United States)

    Ristić-Medić, Danijela; Ristić, Gordana; Tepsić, Vesna

    2003-01-01

    IMPORTANCE AND METABOLISM OF ALPHA-LINOLENIC ACID: Alpha-linolenic acid is an essential fatty acid which cannot be produced in the body and must be taken by food. Both in animals and humans, alpha-linolenic acid is desaturated and elongated into eicosapentaenoic and docosahexaenoic acid. It is also incorporated into plasma and tissue lipids and its conversion is affected by levels of linoleic acid. POTENTIAL ROLE IN PATHOGENESIS OF CARDIOVASCULAR DISEASES: Diet enriched in n-3 fatty acids, especially alpha-linolenic acid, reduces the incidence of cardiac death. Studies have shown that alpha linolenic acid prevents ventricular fibrillation which is the main cause of cardiac death. Studies in rats suggest that alpha-linolenic acid may be more effective in preventing ventricular fibrillations than eicosapentaenoic and docosahexaenoic acid. Furthermore, alpha-linolenic acid is the main fatty acid decreasing platalet aggregation which is an important step in thrombosis i.e. non-fatal myocardial infarction and stroke. DIETARY SOURCES AND NUTRITION RECOMMENDATIONS: Dietary sources include flaxseed and flaxseed oil, canola oil, soybean and soybean oil, pumpkin seed and pumpkin oil, walnuts and walnut oil. Strong evidence supports beneficial effects of alpha-linolenic acid and its dietary sources should be incorporated into balanced diet for prevention of cardiovascular diseases. The recommended daily intake is 2 g with a ratio of 5/1 for linoleic/alpha-linolenic acid. PMID:15510909

  18. Hydroxylated analogues of 5-aminovaleric acid as 4-aminobutyric acidB receptor antagonists

    DEFF Research Database (Denmark)

    Kristiansen, U; Hedegaard, A; Herdeis, C;

    1992-01-01

    The (R) and (S) forms of 5-amino-2-hydroxyvaleric acid (2-OH-DAVA) and 5-amino-4-hydroxyvaleric acid (4-OH-DAVA) were designed as structural hybrids of the 4-aminobutyric acidB (GABAB) agonist (R)-(-)-4-amino-3-hydroxybutyric acid [(R)-(-)-3-OH-GABA] and the GABAB antagonist 5-aminovaleric acid...

  19. 40 CFR 721.2086 - Coco acid triamine condensate, polycarboxylic acid salts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Coco acid triamine condensate... Specific Chemical Substances § 721.2086 Coco acid triamine condensate, polycarboxylic acid salts. (a... coco acid triamine condensate, poly-car-box-ylic acid salts. (PMN P-92-446) is subject to...

  20. Peptide Nucleic Acids Complexes of Two Peptide Nucleic Acid Strands and One

    DEFF Research Database (Denmark)

    1999-01-01

    Peptide nucleic acids and analogues of peptide nucleic acids are used to form duplex, triplex, and other structures with nucleic acids and to modify nucleic acids. The peptide nucleic acids and analogues thereof also are used to modulate protein activity through, for example, transcription arrest...

  1. 5-Caffeoylquinic acid and caffeic acid orally administered suppresses P-selectin expression on mouse platelets

    Science.gov (United States)

    Caffeic acid and 5-caffeoylquinic acid are a naturally occurring phenolic acid and its ester found in human diets. In this paper, potential effects of caffeic acid and 5-caffeoylquinic acid found in coffee and other plant sources on platelet activation were studied via investigating P-selectin expre...

  2. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    NARCIS (Netherlands)

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M.B.

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn

  3. Acid Rain: What It Is -- How You Can Help!

    Science.gov (United States)

    National Wildlife Federation, Washington, DC.

    This publication discusses the nature and consequences of acid precipitation (commonly called acid rain). Topic areas include: (1) the chemical nature of acid rain; (2) sources of acid rain; (3) geographic areas where acid rain is a problem; (4) effects of acid rain on lakes; (5) effect of acid rain on vegetation; (6) possible effects of acid rain…

  4. 2-(3-Hydroxybenzylaminoacetic acid

    Directory of Open Access Journals (Sweden)

    Li-Hua Zhi

    2011-07-01

    Full Text Available There are two independent 2-(3-hydroxybenzylaminoacetic acid molecules, C9H11NO3, in the asymmetric unit of the title compound. The dihedral angle between the benzene rings of the two independent molecules is 58.12 (4°. The crystal packing is stablized by intermolecular O—H...O and N—H...O hydrogen bonds.

  5. Getting folic acid nutrition right

    Science.gov (United States)

    The two articles in this issue of the journal provide some definitive answers to questions relating to folic acid exposure and folate nutritional status of the US population in the post-fortification era, and, by implication, pose other questions. Most convincingly, these reports, which are based la...

  6. Boric Acid in Kjeldahl Analysis

    Science.gov (United States)

    Cruz, Gregorio

    2013-01-01

    The use of boric acid in the Kjeldahl determination of nitrogen is a variant of the original method widely applied in many laboratories all over the world. Its use is recommended by control organizations such as ISO, IDF, and EPA because it yields reliable and accurate results. However, the chemical principles the method is based on are not…

  7. Combinatorics of aliphatic amino acids.

    Science.gov (United States)

    Grützmann, Konrad; Böcker, Sebastian; Schuster, Stefan

    2011-01-01

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

  8. Engineering robust lactic acid bacteria

    NARCIS (Netherlands)

    Bron, P.A.; Bokhorst-van de Veen, van H.; Wels, M.; Kleerebezem, M.

    2011-01-01

    For centuries, lactic acid bacteria (LAB) have been industrially exploited as starter cultures in the fermentation of foods and feeds for their spoilage-preventing and flavor-enhancing characteristics. More recently, the health-promoting effects of LAB on the consumer have been widely acknowledged,

  9. Uric acid in multiple sclerosis

    NARCIS (Netherlands)

    Koch, M; De Keyser, J

    2006-01-01

    Peroxynitrite, a reactive oxidant formed by the reaction of nitric oxide with superoxide at sites of inflammation in multiple sclerosis (MS), is capable of damaging tissues and cells. Uric acid, a natural scavenger of peroxynitrite, reduces inflammatory demyelination in experimental allergic encepha

  10. Alternative to Nitric Acid Passivation

    Science.gov (United States)

    Kessel, Kurt R.

    2015-01-01

    The Ground Systems Development and Operations (GSDO) Program at NASA John F. Kennedy Space Center (KSC), Florida, has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of NASA and the GSDO Program, the objective of this project is to qualify citric acid as an environmentally-preferable alternative to nitric acid for passivation of stainless steel alloys. This project is a direct follow-on to United Space Alliance (USA) work at KSC to optimize the parameters for the use of citric acid and verify effectiveness. This project will build off of the USA study to further evaluate citric acids effectiveness and suitability for corrosion protection of a number of stainless steels alloys used by NASA, the Department of Defense (DoD), and the European Space Agency (ESA).

  11. A route to quantitative 13C NMR analysis of multicomponent polyesters

    DEFF Research Database (Denmark)

    Hvilsted, S.

    1991-01-01

    A protocol for quantitative sequential 13C NMR analysis is developed for polyesters composed of trimethylol propane (TMP), neopentyl glycol (NPG), and adipic and isophthalic acids. TMP centred, structural models with methyl adipate and isophthalate branches in all possible combinations...... on the size of the specific model. This relaxation behaviour defines the experimental conditions for obtaining the quantitative assessment of all polyester polyol structural sequences based on quaternary TMP and NPG carbons. The special case dealt with here additionally centers all acid moieties between...

  12. Hexamethylene Diamine: Shortage in the Short Term and Surplus for the Long Run

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Hexamethylene diamine is mainly used for the production of nylon 6,6 and nylon 6,10 respectively by a neutralization reaction with adipic acid and a reaction with decanedioic acid. Afterwards, nylon 6,6 and nylon 6,10 can be made into various kinds of nylon resins, nylon fiber and engineering plastics.

  13. Quantitative analysis of copolymers : influence of the structure of the monomer on the ionization efficiency in electrospray ionization FTMS

    NARCIS (Netherlands)

    Koster, S.; Mulder, B.; Duursma, M.C.; Boon, J.J.; Philipsen, H.J.A.; Velde, J.W.; Nielen, M.W.F.; Koster, de C.G.; Heeren, R.M.A.

    2002-01-01

    The influence of the ionization efficiency on the measured copolymer sequence distribution is presented. Large differences in ionization efficiency were observed for mixtures of homopolyesters containing dipropoxylated bisphenol A/adipic acid and dipropoxylated bisphenol A/isophthalic acid and the c

  14. Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids.

    Science.gov (United States)

    Banerjee, Amit; Senthilkumar, Soundararasu; Baskaran, Sundarababu

    2016-01-18

    Direct oxidation of the 4,6-O-benzylidene acetal protecting group to C-6 carboxylic acid has been developed that provides an easy access to a wide range of biologically important and synthetically challenging uronic acid and sugar amino acid derivatives in good yields. The RuCl3 -NaIO4 -mediated oxidative cleavage method eliminates protection and deprotection steps and the reaction takes place under mild conditions. The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six-carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues. PMID:26572799

  15. Effect of acetic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    Science.gov (United States)

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-09-01

    An integrated citric acid-methane fermentation process was proposed to solve the problem of extraction wastewater in citric acid fermentation process. Extraction wastewater was treated by anaerobic digestion and then recycled for the next batch of citric acid fermentation to eliminate wastewater discharge and reduce water resource consumption. Acetic acid as an intermediate product of methane fermentation was present in anaerobic digestion effluent. In this study, the effect of acetic acid on citric acid fermentation was investigated and results showed that lower concentration of acetic acid could promote Aspergillus niger growth and citric acid production. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) staining was used to quantify the activity of A. niger cells, and the results suggested that when acetic acid concentration was above 8 mM at initial pH 4.5, the morphology of A. niger became uneven and the part of the cells' activity was significantly reduced, thereby resulting in deceasing of citric acid production. Effects of acetic acid on citric acid fermentation, as influenced by initial pH and cell number in inocula, were also examined. The result indicated that inhibition by acetic acid increased as initial pH declined and was rarely influenced by cell number in inocula.

  16. Eskimo plasma constituents, dihomo-gamma-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid inhibit the release of atherogenic mitogens.

    Science.gov (United States)

    Smith, D L; Willis, A L; Nguyen, N; Conner, D; Zahedi, S; Fulks, J

    1989-01-01

    Studies in man and laboratory animals suggest that omega 3 polyunsaturated fatty acid constituents of fish oils have antiatherosclerotic properties. We have studied the effects of several such polyunsaturated fatty acids for ability to modify the in vitro release of mitogens from human platelets. Such mitogens may produce the fibro-proliferative component of atherosclerotic plaques. Both 5,8,11,14,17-eicosapentaenoic acid (20:5 omega 3) and 4,7,10,13,16,19-docosahexaenoic acid (22:6 omega 3), major constituents of fish oils, inhibited adenosine diphosphate-induced aggregation of platelets and the accompanying release of mitogens. These effects are dose dependent. Linolenic acid (18:3 omega 3), the biosynthetic precursor of eicosapentaenoic acid, also inhibited platelet aggregation and mitogen release. Eicosapentaenoic acid also inhibited mitogen release from human monocyte-derived macrophages, which, in vivo, are an additional source of mitogens during atherogenesis. Potent inhibition of human platelet aggregation and mitogen release was also seen with dihomo-gamma-linolenic acid (8,11,14-eicosatrienoic acid 20:3 omega 6), whose levels are reportedly elevated in Eskimos subsisting on marine diets. We conclude that diets that elevate plasma and/or tissue levels of eicosapentaenoic acid, docosahexaenoic acid and dihomo-gamma-linolenic acid precursor gamma-linolenic acid (18:3 omega 6) may exert antiatherosclerotic effects by inhibiting the release of mitogens from platelets and other cells.

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

    Science.gov (United States)

    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.

  18. Chemical peeling - Glycolic acid versus trichloroacetic acid in melasma

    Directory of Open Access Journals (Sweden)

    Kalla G

    2001-01-01

    Full Text Available Melasma continues to be a therapeutic challenge. 100 patients of melasma not responding to conventional depigmenting agents were divided into 2 groups, one treated with 55 - 75% glycolic acid (68 patients and the other with 10-15% trichloroacetic acid (32 patients. Applications were made after every 15 days and response assessed clinically along with relapse or hyperpigmentation after 3 month follow up period. More than 75% improvement was seen in 30%, and 50-75% improvement in 24% patients. Response with TCA was more rapid as compared to GA. Chronic pigmentation responded more favourably to TCA. Relapse and hyperpigmentation was more-25% in TCA as compared to 5.9% GA. Sun exposure was the most important precipitating factor followed by pregnancy and drugs.

  19. Quinone-amino acid conjugates targeting Leishmania amino acid transporters.

    Science.gov (United States)

    Prati, Federica; Goldman-Pinkovich, Adele; Lizzi, Federica; Belluti, Federica; Koren, Roni; Zilberstein, Dan; Bolognesi, Maria Laura

    2014-01-01

    The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7) to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III) with amino acids (i.e. arginine and lysine) by means of an amide linkage. The toxicity of the synthesized conjugates against Leishmania extracellular (promastigotes) and intracellular (amastigotes) forms was investigated, as well their inhibition of the relevant amino acid transporters. We observed that some conjugates indeed displayed toxicity against the parasites; in particular, 7 was identified as the most potent derivative (at concentrations of 1 µg/mL and 2.5 µg/mL residual cell viability was reduced to 15% and 48% in promastigotes and amastigotes, respectively). Notably, 6, while retaining the cytotoxic activity of quinone II, displayed no toxicity against mammalian THP1 cells. Transport assays indicated that the novel conjugates inhibited transport activity of lysine, arginine and proline transporters. Furthermore, our analyses suggested that the toxic conjugates might be translocated by the transporters into the cells. The non-toxic probes that inhibited transport competed with the natural substrates for binding to the transporters without being translocated. Thus, it is likely that 6, by exploiting amino acid transporters, can selectively deliver its toxic effects to Leishmania cells. This work provides the first evidence that amino acid transporters of the human pathogen Leishmania might be modulated by small molecules, and warrants their further investigation from drug discovery and chemical biology perspectives. PMID:25254495

  20. Quinone-Amino Acid Conjugates Targeting Leishmania Amino Acid Transporters

    OpenAIRE

    Federica Prati; Adele Goldman-Pinkovich; Federica Lizzi; Federica Belluti; Roni Koren; Dan Zilberstein; Maria Laura Bolognesi

    2014-01-01

    The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7) to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III) with amino acids (i.e. arginine and lysine) by means of an amide linkage. The toxi...

  1. Quinone-amino acid conjugates targeting Leishmania amino acid transporters.

    Directory of Open Access Journals (Sweden)

    Federica Prati

    Full Text Available The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7 to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III with amino acids (i.e. arginine and lysine by means of an amide linkage. The toxicity of the synthesized conjugates against Leishmania extracellular (promastigotes and intracellular (amastigotes forms was investigated, as well their inhibition of the relevant amino acid transporters. We observed that some conjugates indeed displayed toxicity against the parasites; in particular, 7 was identified as the most potent derivative (at concentrations of 1 µg/mL and 2.5 µg/mL residual cell viability was reduced to 15% and 48% in promastigotes and amastigotes, respectively. Notably, 6, while retaining the cytotoxic activity of quinone II, displayed no toxicity against mammalian THP1 cells. Transport assays indicated that the novel conjugates inhibited transport activity of lysine, arginine and proline transporters. Furthermore, our analyses suggested that the toxic conjugates might be translocated by the transporters into the cells. The non-toxic probes that inhibited transport competed with the natural substrates for binding to the transporters without being translocated. Thus, it is likely that 6, by exploiting amino acid transporters, can selectively deliver its toxic effects to Leishmania cells. This work provides the first evidence that amino acid transporters of the human pathogen Leishmania might be modulated by small molecules, and warrants their further investigation from drug discovery and chemical biology perspectives.

  2. Bioisosteric modifications of 2-arylureidobenzoic acids

    DEFF Research Database (Denmark)

    Valgeirsson, Jon; Nielsen, Elsebet O; Peters, Dan;

    2004-01-01

    2-Arylureidobenzoic acids (AUBAs) have recently been presented as the first series of selective noncompetitive GluR5 antagonists. In this paper we have modified the acidic moiety of the AUBAs by introducing different acidic and neutral groups, and similarly, we have replaced the urea linker...... of the AUBAs with other structurally related linkers. Replacing the acid with neutral substituents led to inactive compounds in all instances, showing that an acidic moiety is necessary for activity. Replacing the carboxylic moiety in 2a with a sulfonic acid (5c) or a tetrazole ring (5d) improved the potency...

  3. Endocrine and paracrine role of bile acids

    Institute of Scientific and Technical Information of China (English)

    Verena Keitel; Ralf Kubitz; Dieter H(a)ussinger

    2008-01-01

    Bile acids are not only important for the absorption of dietary lipids and fat soluble vitamins but are signalling molecules with diverse endocrine and paracrine functions.Bile acids regulate bile acid,lipid and glucose metabolism and modulate temperature and energy homeostasis.Furthermore,bile acids can not only promote cell proliferation and liver regeneration but can also induce programmed cell death.Bile acid functions are mediated through different pathways which comprise the activation of nuclear hormone receptors,of intracellular kinases and of the plasma membranebound,G-protein coupled bile acid receptor TGR5/Gpbar-1.

  4. Oxidation-reduction reactions of simple hydroxamic acids and plutonium(IV) ions in nitric acid

    OpenAIRE

    Carrott, M. J.; Fox, O. D.; LeGurun, G.; Jones, C J; Mason, C; Taylor, Robin; Andrieux, Fabrice; Boxall, Colin

    2008-01-01

    Simple hydroxamic acids such as formo- and aceto-hydroxamic acids have been proposed as suitable reagents for the separation of either Pu and/or Np from U in modified or single cycle Purex based solvent extraction processes designed to meet the emerging requirements of advanced fuel cycles. The stability of these hydroxamic acids is dominated by their decomposition through acid hydrolysis. Kinetic studies of the acid hydrolysis of formo- and acetohydroxamic acids are reported in the absence a...

  5. Accidental intoxication with hydrochloric acid and hydrofluoric acid mixture

    Directory of Open Access Journals (Sweden)

    Anna Smędra-Kaźmirska

    2014-08-01

    Full Text Available The paper describes a fatal case of accidental ingestion of a mixture of hydrochloric acid and hydrofluoric acid. The man was admitted to hospital, where appropriate treatment, adequate to his condition, was instituted. Numerous ventricular fibrillation episodes, for which the patient was defibrillated repeatedly, were observed during the period of hospitalization. The patient was in a critical condition, with progressive symptoms of hypovolemic shock and multiorgan failure. On the next day after admission, signs of electromechanical dissociation progressing to asystole were noted. The instituted resuscitation procedure proved ineffective and the patient died. Autopsy revealed brownish discoloration of the esophageal, gastric, and small intestinal mucous membranes. Numerous ulcerations without signs of perforation were found both in the esophagus and in the stomach. The mucous membrane of the small intestine demonstrated focal rubefactions, whereas no focal lesions of the large intestinal mucosa were seen. Microscopic investigation of the biopsy specimens collected from the stomach, duodenum and small intestine revealed mucous membrane necrosis foci, reaching the deeper layers of the wall of these organs. The mucous membrane of the large intestine was congested. Bioptates obtained from the lungs indicated the presence of hemorrhagic infarcts and focal extravasations. Poisoning with the aforementioned acids with consequent necrosis of the esophageal, gastric, duodenal and small intestinal walls with hemorrhages to the gastrointestinal tract, as well as extravasations and hemorrhagic infarcts in the lungs was considered to be the cause of death.

  6. Accidental intoxication with hydrochloric acid and hydrofluoric acid mixture.

    Science.gov (United States)

    Smędra-Kaźmirska, A; Kędzierski, M; Barzdo, M; Jurczyk, Ap; Szram, S; Berent, J

    2014-01-01

    The paper describes a fatal case of accidental ingestion of a mixture of hydrochloric acid and hydrofluoric acid. The man was admitted to hospital, where appropriate treatment, adequate to his condition, was instituted. Numerous ventricular fibrillation episodes, for which the patient was defibrillated repeatedly, were observed during the period of hospitalization. The patient was in a critical condition, with progressive symptoms of hypovolemic shock and multiorgan failure. On the next day after admission, signs of electromechanical dissociation progressing to asystole were noted. The instituted resuscitation procedure proved ineffective and the patient died. Autopsy revealed brownish discoloration of the esophageal, gastric, and small intestinal mucous membranes. Numerous ulcerations without signs of perforation were found both in the esophagus and in the stomach. The mucous membrane of the small intestine demonstrated focal rubefactions, whereas no focal lesions of the large intestinal mucosa were seen. Microscopic investigation of the biopsy specimens collected from the stomach, duodenum and small intestine revealed mucous membrane necrosis foci, reaching the deeper layers of the wall of these organs. The mucous membrane of the large intestine was congested. Bioptates obtained from the lungs indicated the presence of hemorrhagic infarcts and focal extravasations. Poisoning with the aforementioned acids with consequent necrosis of the esophageal, gastric, duodenal and small intestinal walls with hemorrhages to the gastrointestinal tract, as well as extravasations and hemorrhagic infarcts in the lungs was considered to be the cause of death.

  7. Spontaneous curvature of phosphatidic acid and lysophosphatidic acid.

    Science.gov (United States)

    Kooijman, Edgar E; Chupin, Vladimir; Fuller, Nola L; Kozlov, Michael M; de Kruijff, Ben; Burger, Koert N J; Rand, Peter R

    2005-02-15

    The formation of phosphatidic acid (PA) from lysophosphatidic acid (LPA), diacylglycerol, or phosphatidylcholine plays a key role in the regulation of intracellular membrane fission events, but the underlying molecular mechanism has not been resolved. A likely possibility is that PA affects local membrane curvature facilitating membrane bending and fission. To examine this possibility, we determined the spontaneous radius of curvature (R(0p)) of PA and LPA, carrying oleoyl fatty acids, using well-established X-ray diffraction methods. We found that, under physiological conditions of pH and salt concentration (pH 7.0, 150 mM NaCl), the R(0p) values of PA and LPA were -46 A and +20 A, respectively. Thus PA has considerable negative spontaneous curvature while LPA has the most positive spontaneous curvature of any membrane lipid measured to date. The further addition of Ca(2+) did not significantly affect lipid spontaneous curvature; however, omitting NaCl from the hydration buffer greatly reduced the spontaneous curvature of PA, turning it into a cylindrically shaped lipid molecule (R(0p) of -1.3 x 10(2) A). Our quantitative data on the spontaneous radius of curvature of PA and LPA at a physiological pH and salt concentration will be instrumental in developing future models of biomembrane fission. PMID:15697235

  8. Anti-Diabetic Effects of Madecassic Acid and Rotundic Acid

    Directory of Open Access Journals (Sweden)

    Yuan-Man Hsu

    2015-12-01

    Full Text Available Anti-diabetic effects of madecassic acid (MEA and rotundic acid (RA were examined. MEA or RA at 0.05% or 0.1% was supplied to diabetic mice for six weeks. The intake of MEA, not RA, dose-dependently lowered plasma glucose level and increased plasma insulin level. MEA, not RA, intake dose-dependently reduced plasminogen activator inhibitor-1 activity and fibrinogen level; as well as restored antithrombin-III and protein C activities in plasma of diabetic mice. MEA or RA intake decreased triglyceride and cholesterol levels in plasma and liver. Histological data agreed that MEA or RA intake lowered hepatic lipid droplets, determined by ORO stain. MEA intake dose-dependently declined reactive oxygen species (ROS and oxidized glutathione levels, increased glutathione content and maintained the activity of glutathione reductase and catalase in the heart and kidneys of diabetic mice. MEA intake dose-dependently reduced interleukin (IL-1β, IL-6, tumor necrosis factor-α and monocyte chemoattractant protein-1 levels in the heart and kidneys of diabetic mice. RA intake at 0.1% declined cardiac and renal levels of these inflammatory factors. These data indicated that MEA improved glycemic control and hemostatic imbalance, lowered lipid accumulation, and attenuated oxidative and inflammatory stress in diabetic mice. Thus, madecassic acid could be considered as an anti-diabetic agent.

  9. Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

    Science.gov (United States)

    Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

    1990-01-01

    The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

  10. Linoleic acid: between doubts and certainties.

    Science.gov (United States)

    Choque, Benjamin; Catheline, Daniel; Rioux, Vincent; Legrand, Philippe

    2014-01-01

    Linoleic acid is the most abundant polyunsaturated fatty acid in human nutrition and represents about 14 g per day in the US diet. Following the discovery of its essential functions in animals and humans in the early 1920's, studies are currently questioning the real requirement of linoleic acid. It seems now overestimated and creates controversy: how much linoleic acid should be consumed in a healthy diet? Beyond the necessity to redefine the dietary requirement of linoleic acid, many questions concerning the consequences of its excessive consumption on human health arise. Linoleic acid is a direct precursor of the bioactive oxidized linoleic acid metabolites. It is also a precursor of arachidonic acid, which produces pro-inflammatory eicosanoids and endocannabinoids. A majority of the studies on linoleic acid and its derivatives show a direct/indirect link with inflammation and metabolic diseases. Many authors claim that a high linoleic acid intake may promote inflammation in humans. This review tries to (i) highlight the importance of reconsidering the actual requirement of linoleic acid (ii) point out the lack of knowledge between dietary levels of linoleic acid and the molecular mechanisms explaining its physiological roles (iii) demonstrate the relevance of carrying out further human studies on the single variable linoleic acid.

  11. Thermochemistry of aqueous pyridine-3-carboxylic acid (nicotinic acid)

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Elsa M. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Instituto Politecnico de Setubal, ESTBarreiro, Rua Americo da Silva Marinho, 2839-001 Lavradio (Portugal); Rego, Talita S. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Minas da Piedade, Manuel E., E-mail: memp@fc.ul.p [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal)

    2011-06-15

    Research highlights: {yields} We determined the {Delta}{sub sol}H{sub m} of solid nicotinic acid (NA) in water by solution calorimetry. {yields} We determined {Delta}{sub dil}H{sub m} of an aqueous nicotinic acid solution by flow calorimetry. {yields} We determined (aq, {infinity}) for the 3 NA species involved in acid/base equilibria. {yields} We determined the enthalpy of formation of NA(aq) under saturation conditions.. - Abstract: The molar enthalpy of solution of solid nicotinic acid (NA) at T = 298.15 K, to give an aqueous solution of molality m = 3.748 . 10{sup -3} mol {center_dot} kg{sup -1}, was determined as {Delta}{sub sol}H{sub m} = (19,927 {+-} 48) J {center_dot} mol{sup -1}, by solution calorimetry. Enthalpies of dilution, {Delta}{sub dil}H{sub m}, of 0.1005 mol {center_dot} kg{sup -1} aqueous nicotinic acid to yield final solutions with molality in the approximate range (0.03 to 0.09) mol {center_dot} kg{sup -1} were also measured by flow calorimetry. Combining the two sets of data and the results of pH measurements, with values of proton dissociation enthalpies and {Delta}{sub f}H{sub m}{sup 0}(NA, cr) selected from the literature, it was possible to derive the standard molar enthalpies of formation of the three nicotinic acid species involved in protonation/deprotonation equilibria, at infinite dilution: {Delta}{sub f}H{sub m}{sup 0}(HN{sup +}C{sub 5}H{sub 4}COOH.{infinity}H{sub 2}O,aq) = (328.2 {+-} 1.2) kJ {center_dot} mol{sup -1}, {Delta}{sub f}H{sub m}{sup 0}(HN{sup +}C{sub 5}H{sub 4}COO{sup -}.{infinity}H{sub 2}O,aq) = (325.0 {+-} 1.2) kJ {center_dot} mol{sup -1}, and {Delta}{sub f}H{sub m}{sup 0}(NC{sub 5}H{sub 4}COO{sup -}.{infinity}H{sub 2}O,aq) = (313.7 {+-} 1.2) kJ {center_dot} mol{sup -1}. Finally, the enthalpy of solution of nicotinic acid at T = 298.15 K, under saturation conditions (m = 0.138 mol {center_dot} kg{sup -1}), and the standard molar enthalpy of formation of the corresponding solution could also be obtained as {Delta

  12. Prenatal long-chain polyunsaturated fatty acid status : the importance of a balanced intake of docosahexaenoic acid and arachidonic acid

    NARCIS (Netherlands)

    Hadders-Algra, Mijna

    2008-01-01

    This review addresses the effect of prenatal long-chain polyunsaturated fatty acid (LCPUFA) status on neuro-developmental outcome. It focuses on the major LPCUFA doxosahexaenoic acid (DNA; 22:6 omega 3) and arachidonic acid (AA; 20:4 omega 6). Due to enzymatic competition high DHA intake results in

  13. Effect of supplementation of arachidonic acid (AA) or a combination of AA plus docosahexaenoic acid on breastmilk fatty acid composition

    NARCIS (Netherlands)

    Smit, EN; Koopmann, M; Boersma, ER; Muskiet, FAJ

    2000-01-01

    We investigated whether supplementation with arachidonic acid (20:4 omega 6; AA), ora combination of AA and docosahexaenoic acid (22:6 omega 3; DHA) would affect human milk polyunsaturated fatty acid (PUFA) composition. Ten women were daily supplemented with 300 mg AA, eight with 300 mg AA, 110 mg e

  14. [Inherited amino acid transport disorders].

    Science.gov (United States)

    Igarashi, Y; Tada, K

    1992-07-01

    Disorders due to inherited amino acids transport defect are reviewed. The disorders were categorized into three types of transport defects, namely, brush-border membrane of epithelial cells of small intestine and kidney tubules (Hartnup disease, blue diaper syndrome, cystinuria, iminoglycinuria and lysine malabsorption syndrome), basolateral membrane (lysinuric protein intolerance) and membrane of intracellular organelles (cystinosis and hyperornitinemia-hyperammonemia-homocitrullinuria syndrome). Pathogenesis, clinical feature, laboratory findings, diagnosis, genetics and treatment of these disorders are described, briefly. There is not much data for the transport systems themselves, so that further investigation in molecular and gene levels for transport systems is necessary to clarify the characteristics of the transport and heterogeneity of phenotypes in inherited amino acids transport disorders. PMID:1404888

  15. Nucleic acid based logical systems.

    Science.gov (United States)

    Han, Da; Kang, Huaizhi; Zhang, Tao; Wu, Cuichen; Zhou, Cuisong; You, Mingxu; Chen, Zhuo; Zhang, Xiaobing; Tan, Weihong

    2014-05-12

    Researchers increasingly visualize a significant role for artificial biochemical logical systems in biological engineering, much like digital logic circuits in electrical engineering. Those logical systems could be utilized as a type of servomechanism to control nanodevices in vitro, monitor chemical reactions in situ, or regulate gene expression in vivo. Nucleic acids (NA), as carriers of genetic information with well-regulated and predictable structures, are promising materials for the design and engineering of biochemical circuits. A number of logical devices based on nucleic acids (NA) have been designed to handle various processes for technological or biotechnological purposes. This article focuses on the most recent and important developments in NA-based logical devices and their evolution from in vitro, through cellular, even towards in vivo biological applications.

  16. Europium complexes with trifluoroacetic acid

    International Nuclear Information System (INIS)

    Synthesis conditions and spectra-luminescent properties of different-ligand europium complexes of the composition Eu (TFA)2x2D, where TFA = anion of trifluoroacetic acid, D = 1,10-phenanthroline, 2,2-dipyridyl, triphenylphosphinoxide, hexamethyl-phosphotriamide, were studied. The compounds prepared have been characterized by the methods of elementary chemical analysis, IR and luminescence spectroscopy. It is shown that in the complex compounds two methods of coordination of the acid residue functional groups are realized, i.e. monodentate and bridge functions. The compounds were tested for resistance to UV light effect and to heating in the air. Complex with 2,2-dipyridyl proved the most thermally stable complex in the series studied, its decomposition temperature being 240 deg C

  17. Ursodeoxycholic acid and superoxide anion

    Institute of Scientific and Technical Information of China (English)

    Predrag Ljubuncic; Omar Abu-Salach; Arieh Bomzon

    2005-01-01

    AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O2--induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants.RESULTS: UDCA at a concentration as high as 1 mmol/Ldid not impair the ability of the X-XO system to generate O2-, but could scavenge O2- at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 μmol/L.CONCLUSION: UDCA can scavenge O2-, an action that may be beneficial to patients with primary biliary cirrhosis.

  18. Palmitic Acid and Health: Introduction.

    Science.gov (United States)

    Agostoni, Carlo; Moreno, Luis; Shamir, Raanan

    2016-09-01

    Interest in the dietary role and metabolic effect of saturated fatty acids has been recently renewed on the basis of epidemiologic observations and economical approach to health and well-being. Saturated fats may favorably increase blood HDL-Cholesterol levels without significant changes of the total cholesterol/HDL-Cholesterol ratio. Also, the negative effect of saturated fat on cardiovascular diseases risk has recently been challenged. Palmitic acid, among all, may have special structural and functional roles in utero and in infancy, and indeed is it is being delivered in a unique form in human milk. Future research should include objective cost-benefit analyses when disentangling the role of saturated fats in dietary recommendations. PMID:25764181

  19. Nucleic Acid Aptamers Against Proteases

    OpenAIRE

    Dupont, D M; Andersen, L M; Bøtkjær, Kenneth Alrø; Andreasen, P A

    2011-01-01

    Proteases are potential or realized therapeutic targets in a wide variety of pathological conditions. Moreover, proteases are classical subjects for studies of enzymatic and regulatory mechanisms. We here review the literature on nucleic acid aptamers selected with proteases as targets. Designing small molecule protease inhibitors of sufficient specificity has proved a daunting task. Aptamers seem to represent a promising alternative. In our review, we concentrate on biochemical mechanisms of...

  20. Rechargeable lead-acid batteries.

    Science.gov (United States)

    1990-09-01

    Batteries used in medical equipment, like their counterparts in consumer products, attract little attention until they fail to function effectively. In some applications, such as in emergency medical devices, battery failure can have fatal consequences. While modern batteries are usually quite reliable, ECRI has received 53 written problem reports and countless verbal reports or questions related to battery problems in hospitals during the past five years. This large number of reports is due, at least in part, to the enormous quality of batteries used to operate or provide backup power in contemporary hospital equipment. As part of an ongoing evaluation of rehabilitation assistive equipment, ECRI has been studying the performance of 12 V rechargeable deep-cycle lead-acid batteries used in powered wheelchairs. During the course of this evaluation, it has become apparent that many professionals, both clinical and industrial, regard batteries as "black box" devices and know little about proper care and maintenance--and even less about battery selection and purchase. Because equipment performance and reliability can be strongly influenced by different battery models, an understanding of battery characteristics and how they affect performance is essential when selecting and purchasing batteries. The types of rechargeable batteries used most commonly in hospitals are lead-acid and nickel-cadmium (nicad), which we compare below; however, the guidance we provide in this article focuses on lead-acid batteries. While the examples given are for high-capacity 12 V deep-cycle batteries, similar analyses can be applied to smaller lead-acid batteries of different voltages.

  1. Oleic acid biosynthesis in cyanobacteria

    International Nuclear Information System (INIS)

    The biosynthesis of fatty acids in cyanobacteria is very similar to the well characterized system found in green plants. However, the initial desaturation of stearic acid in cyanobacteria appears to represent a significant departure from plant systems in which stearoyl-ACP is the exclusive substrate for desaturation. In Anabaena variabilis, the substrate appears to be monoglucosyldiacylglycerol, a lipid not found in plants. The authors examined five different cyanobacteria to determine if the pathway in A. variabilis was generally present in other cyanobacteria. The cyanobacteria studied were A. variabilis, Chlorogloeopsis sp., Schizothrix calcicola, Anacystis marina, and Anacystis nidulans. Each were grown in liquid culture, harvested, and examined for stearoyl-ACP desaturase activity or incubated with 14CO2. None of the cyanobacteria contained any stearoyl-ACP desaturase activity in whole homogenates or 105,000g supernatants. All were capable of incorporating 14CO2 into monoglucosyldiacylglycerol and results from incubations of 20 min, 1 hr, 1 hr + 10 hr chase were consistent with monoglucosyldiacylglycerol serving as precursor for monogalctosyldiacylglycerol. Thus, initial evidence is consistent with oleic acid biosynthesis occurring by desaturation of stearoyl-monoglucosyldiacylglycerol in all cyanobacteria

  2. Thermal Stability Of Formohydroxamic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F. F.; Rudisill, T. S.

    2011-10-21

    The thermal stability of formohydroxamic acid (FHA) was evaluated to address the potential for exothermic decomposition during storage and its use in the uranium extraction process. Accelerating rate calorimetry showed rapid decomposition at a temperature above 65 {degree}C; although, the rate of pressure rise was greater than two orders of magnitude less than the lower bound for materials which have no explosive properties with respect to transportation. FHA solutions in water and nitric acid did not reach runaway conditions until 150 {degree}C. Analysis by differential scanning calorimetry showed that FHA melted at 67 {degree}C and thermally decomposed at 90 {degree}C with an enthalpy of -1924 J/g. The energics of the FHA thermal decomposition are comparable to those measured for aqueous solutions of hydroxylamine nitrate. Solid FHA should be stored in a location where the temperature does not exceed 20-25 {degree}C. As a best practice, the solid material should be stored in a climate-controlled environment such as a refrigerator or freezer. FHA solutions in water are not susceptible to degradation by acid hydrolysis and are the preferred way to handle FHA prior to use.

  3. Acid Rain: The Silent Environmental Threat.

    Science.gov (United States)

    Zmud, Mia

    1992-01-01

    Describes the silent environmental threat posed by acid rain. Caused mainly by manmade pollutants, acid rain damages water and trees, decreases visibility, corrodes monuments, and threatens public health. The article includes guidelines for action. (SM)

  4. Nature in the Classroom: Acid Rain.

    Science.gov (United States)

    Doyle, Charles

    1982-01-01

    As a lesson topic, acid rain is defined, its chemistry given, and its development since the 1950s described. The worldwide effects of acid rain are discussed along with the available technology for controlling the problem. (CM)

  5. How Acid Reflux Disease Damages Teeth

    Science.gov (United States)

    ... more Seniors' Oral Health How to Keep Your Teeth for a Lifetime Tooth loss is simply the ... your desktop! more... How Acid Reflux Disease Damages Teeth Article Chapters How Acid Reflux Disease Damages Teeth ...

  6. Acid rain information book. Second edition

    International Nuclear Information System (INIS)

    Potential consequences of widespread acid precipitation are reviewed through an extensive literature search. Major aspects of the acid rain phenomena are discussed, areas of uncertainty identified, and current research summarized

  7. Bile acids for primary sclerosing cholangitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Gluud, C

    2003-01-01

    Bile acids have been used for treating primary sclerosing cholangitis, but their beneficial and harmful effects remain unclear.......Bile acids have been used for treating primary sclerosing cholangitis, but their beneficial and harmful effects remain unclear....

  8. Histidine-Containing Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2000-01-01

    Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics.......Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics....

  9. Role of succinic acid in chemical evolution

    Science.gov (United States)

    Negron-Mendoza, A.; Ponnamperuma, C.

    1982-01-01

    Succinic acid is converted into other carboxylic acids by ionizing radiation. The results obtained have been correlated with the ready formation of this compound in prebiotic experiments. Its role in biological systems may be related to its prebiotic occurrence.

  10. RETINOIC ACID ALTERS EPITHELIAL DIFFERENTIATION DURING PALATOGENESIS

    Science.gov (United States)

    Retinoids are teratogenic in humans and animals, producing a syndrome of craniofacial malformations which includes cleft palate. his study investigates the mechanism through which retinoic acid induces cleft palate. urine palatogenesis after exposure to retinoic acid in utero is ...

  11. Self-breaking retarded acid emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Scherubel, G.A.

    1979-02-20

    A subterranean formation is acidized with an acid-in-oil emulsion consisting of an aqueous acidizing solution, an oil, an alkyl C/sub 8/ to C/sub 18/ primary fatty amine, and at least one diethanolamide of at least one C/sub 8/ to C/sub 18/ fatty acid. The present invention is an improved acid-in-oil acidizing emulsion, and acidizing method such as an emulsion, the emulsion being of the type containing an effective amount of at least one C/sub 8/ to C/sub 18/ primary amine as a cationic surfactant to increase the normal reaction. The diethanolamine is a nonionic surfactant which causes the emulsion to break as the acidizing capacity of the emulsion becomes substantially depleted, i.e., spent, on the formation. 41 claims.

  12. Profile of Fatty Acids, Amino Acids, Carotenoid Total, and α-Tocopherol from Flying Fish Eggs

    Directory of Open Access Journals (Sweden)

    Aulia Azka

    2015-12-01

    Full Text Available Flying fish are found in waters of eastern Indonesia, which until now is still limited information about nutritional content. The purpose of this research was determine the composition of fatty acids, amino acids, total carotenoids, α-tocopherol flying fish eggs (Hyrundicthys sp.. The composition of fatty acid was measured by gas chromatography (GC, while amino acids, total carotenoids, α-tocopherol was measured by High performanced Liquid Chromatography (HPLC. Egg contained 22 fatty acids such as saturated fatty acid 29.71%, monounsaturated fatty acid 7.86%, and polysaturated fatty acid 13.64%. The result showed that eggs flying fish contained 17 amino acids, such as essential amino acid 14.96% and non-essential amino acids 20.27%. Eggs contained a total carotenoid of 245.37 ppm. α-tocopherol content of flying fish eggs by 1.06 ppm.

  13. Capture and release of acid-gasses with acid-gas binding organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Heldebrant, David J; Yonker, Clement R; Koech, Phillip K

    2015-03-17

    A system and method for acid-gas capture wherein organic acid-gas capture materials form hetero-atom analogs of alkyl-carbonate when contacted with an acid gas. These organic-acid gas capture materials include combinations of a weak acid and a base, or zwitterionic liquids. This invention allows for reversible acid-gas binding to these organic binding materials thus allowing for the capture and release of one or more acid gases. These acid-gas binding organic compounds can be regenerated to release the captured acid gasses and enable these organic acid-gas binding materials to be reused. This enables transport of the liquid capture compounds and the release of the acid gases from the organic liquid with significant energy savings compared to current aqueous systems.

  14. The Use of Acid-Aluminium Tolerant Bradyrhizobium japonicum Inoculant for Soybean Grown on Acid Soils

    Directory of Open Access Journals (Sweden)

    ANGELIA REZTY FITRIANI SITUMORANG

    2009-12-01

    Full Text Available Land with low pH soil spread widely in Indonesia can be used for soybean (Glycine max cultivation, although the production is low. The use of acid tolerant soybean and acid-Al tolerant nitrogen-fixing bacteria was an alternative way to increase soybean productivity on acid soils. This research was conducted to study the influence of acid-Al tolerant Bradyrhizobium japonicum on growth of Slamet cultivar soybean planted on acid soils in greenhouse. Three strains of acid-Al tolerant B. japonicum, i.e. BJ 11 (19, BJ 11 (5, and BJ 11 (wt, were used in this experiment. The result showed that inoculation of all acid-Al tolerant B. japonicum strains could increase plant height, shoot and root weight, number of flowers, pods, seeds, seeds dry weight, and shoot and seed nitrogen content.

  15. Analysis of the apple fruit acid/low-acid trait by SSR markers

    Institute of Scientific and Technical Information of China (English)

    Yuxin YAO; Heng ZHAI; Lingling ZHAO; Kai YI; Zhi LIU; Ye SONG

    2008-01-01

    It is necessary to find out the genetic character-istics of malic acid in the course of apple genomic research and breeding. In this study, the SSR marker linked to the acid/low-acid trait in apple fruit was identified from 140 SSR primer pairs, using 91 F1 population hybrids from the intra-specific cross between apple cultivar 'Dongguang' and 'Fuji' as the experimental materials. Of 140 SSR primer pairs, only primer SDY085 produced a polymorphic band linked to acid trait, and the linkage distance was 8.89 cM. Also, the titrated acid and malic acid in different developmental stages were determined. The SSR marker analysis, coupled with the change of the total acid and malic acid contents, revealed that the acid/low-acid trait was governed by a major gene and acid trait was completely dominant.

  16. Incorporation of conjugated linoleic acid (CLA and α-linolenic acid (LNA in pacu fillets

    Directory of Open Access Journals (Sweden)

    Deoclécio José Barilli

    2014-03-01

    Full Text Available The objective of this study was to evaluate the incorporation of conjugated linoleic acid and α-linolenic acid in fillets of pacu fish raised in net cages and fed diets enriched with these acids. The fish were fed for 49 days, and at the end of this period the fatty acid content in the fillets was determined by gas chromatography. Concentrations of α-linolenic acid, eicosapentaenoic acid, and the total omega-3 (n-3 fatty acid in the fillets increased, improving the n-6/n-3 ratio. In addition, the incorporation of conjugated linoleic acid in the fish fillets proved well established. This study showed that the use of diets enriched with conjugated linoleic acid and α-linolenic acid results in the incorporation of these acids in the of pacu fish fillets, improving their nutritional quality.

  17. Drug Nanoparticle Formulation Using Ascorbic Acid Derivatives

    OpenAIRE

    Kunikazu Moribe; Waree Limwikrant; Kenjirou Higashi; Keiji Yamamoto

    2011-01-01

    Drug nanoparticle formulation using ascorbic acid derivatives and its therapeutic uses have recently been introduced. Hydrophilic ascorbic acid derivatives such as ascorbyl glycoside have been used not only as antioxidants but also as food and pharmaceutical excipients. In addition to drug solubilization, drug nanoparticle formation was observed using ascorbyl glycoside. Hydrophobic ascorbic acid derivatives such as ascorbyl mono- and di-n-alkyl fatty acid derivatives are used either as drugs...

  18. 21 CFR 184.1005 - Acetic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acetic acid. 184.1005 Section 184.1005 Food and... Substances Affirmed as GRAS § 184.1005 Acetic acid. (a) Acetic acid (C2H4O2, CAS Reg. No. 64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation...

  19. Enhancement of colposcopic image by sulphosalicylic acid.

    Directory of Open Access Journals (Sweden)

    Khilnani P

    1993-01-01

    Full Text Available Acetic acid is used conventionally for enhancement of the colposcopic image. We used sulphosalicylic acid instead of acetic acid in 50 normal cases. The normal appearance was enhanced in all cases. The image was also enhanced in 70% cases of cervical intraepithelial neoplasia and 90% cases of cervical condyloma accuminata. The image was not inferior to that with acetic acid in any of the cases.

  20. Complicated Composting: Persistent Pyridine Carboxylic Acid Herbicides

    OpenAIRE

    Reimer, Julie

    2013-01-01

    This paper reviews pyridine carboxylic acid herbicide impacts on compost. Pyridine carboxylic acid herbicides are not completely broken down during grass growth, harvest and drying of hay, in the digestive tract of livestock, or during composting. These herbicides are a popular choice for broadleaf weed control because of this persistence: they remain effective for months or years. Pyridine carboxylic acids are also more effective than the common herbicide 2, 4-dichlorophenoxyacetic acid and ...

  1. Direct Channeling of Retinoic Acid between Cellular Retinoic Acid-Binding Protein II and Retinoic Acid Receptor Sensitizes Mammary Carcinoma Cells to Retinoic Acid-Induced Growth Arrest

    OpenAIRE

    Budhu, Anuradha S.; Noy, Noa

    2002-01-01

    Cellular retinoic acid-binding protein II (CRABP-II) is an intracellular lipid-binding protein that associates with retinoic acid with a subnanomolar affinity. We previously showed that CRABP-II enhances the transcriptional activity of the nuclear receptor with which it shares a common ligand, namely, the retinoic acid receptor (RAR), and we suggested that it may act by delivering retinoic acid to this receptor. Here, the mechanisms underlying the effects of CRABP-II on the transcriptional ac...

  2. Microbial production of natural poly amino acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Three kinds of poly amino acids, poly-γ-glutamic acid, poly(ε-L-lysine) and multi-L-arginyl-poly (L-aspartic acid) can be synthesized by enzymatic process independently from ribosomal protein biosynthesis pathways in microorganism. These biosynthesized polymers have attracted more and more attentions because of their unique properties and various applications. In this review, the current knowledge on the biosynthesis, biodegradations and applications of these three poly amino acids are summarized.

  3. Fatty Acid Composition of Agaricus bisporus (Lange) Sing.

    OpenAIRE

    Aktümsek, Abdurrahman; ÖZTÜRK, Celâleddin; KAŞIK, Giyasettin

    1998-01-01

    Fatty acid compositions of fruit body, stem, lamellae and total of Agaricus bisporus were seperately analysed by GLC. In the all fatty acid compositions of A. bisporus, linoleic acid were predominant. Percentages of linoleic acid were varied between 53.45 - 68.78%. It was showed that the other major fatty acids were palmitic, oleic and stearic acid in the fatty acid compositions.

  4. Acrylic Acid and Esters Will Be Oversupply

    Institute of Scientific and Technical Information of China (English)

    Zheng Chengwang

    2007-01-01

    @@ Drastic capacity growth The production capacity of acrylic acid in China has grown drastically in recent years. With the completion of the 80 thousand t/a acrylic acid and 130 thous and t/a acrylic ester project in Shenyang Paraffin Chemical Industrial Co., Ltd., (CCR2006,No. 31) the capacity of acrylic acid in China has reached 882 thousand t/a.

  5. Treating burns caused by hydrofluoric acid.

    Science.gov (United States)

    Summers, Anthony

    2011-06-01

    Hydrofluoric acid is an ingredient of many common household and industrial solutions. Even seemingly minor burns caused by this acid can have catastrophic effects if they are treated inappropriately or late. This article describes the signs and symptoms, the pathophysiology and the emergency management of hydrofluoric acid burns.

  6. Hydrofluoric acid on dentin should be avoided.

    NARCIS (Netherlands)

    Loomans, B.A.C.; Mine, A.; Roeters, F.J.M.; Opdam, N.J.M.; Munck, J. De; Huysmans, M.C.D.N.J.M.; Meerbeek, B. Van

    2010-01-01

    Hydrofluoric acid can be used for intra-oral repair of restorations. Contamination of tooth substrate with hydrofluoric acid cannot always be avoided. OBJECTIVES: To investigate the bonding effectiveness to hydrofluoric acid contaminated dentin by, micro-tensile bond strength testing, SEM and TEM. M

  7. Lipoxygenase inhibitory activity of anacardic acids.

    Science.gov (United States)

    Ha, Tae Joung; Kubo, Isao

    2005-06-01

    6[8'(Z)-pentadecenyl]salicylic acid, otherwise known as anacardic acid (C15:1), inhibited the linoleic acid peroxidation catalyzed by soybean lipoxygenase-1 (EC 1.13.11.12, type 1) with an IC50 of 6.8 microM. The inhibition of the enzyme by anacardic acid (C15:1) is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Dixon plots indicates that anacardic acid (C15:1) is a competitive inhibitor and the inhibition constant, KI, was obtained as 2.8 microM. Although anacardic acid (C15:1) inhibited the linoleic acid peroxidation without being oxidized, 6[8'(Z),11'(Z)-pentadecadienyl]salicylic acid, otherwise known as anacardic acid (C15:2), was dioxygenated at low concentrations as a substrate. In addition, anacardic acid (C15:2) was also found to exhibit time-dependent inhibition of lipoxygenase-1. The alk(en)yl side chain of anacardic acids is essential to elicit the inhibitory activity. However, the hydrophobic interaction alone is not enough because cardanol (C15:1), which possesses the same side chain as anacardic acid (C15:1), acted neither as a substrate nor as an inhibitor. PMID:15913294

  8. 21 CFR 582.6033 - Citric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Citric acid. 582.6033 Section 582.6033 Food and..., FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 2 § 582.6033 Citric acid. (a) Product. Citric acid. 2 For the purpose of this subpart, no attempt has been made...

  9. 21 CFR 582.1033 - Citric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Citric acid. 582.1033 Section 582.1033 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1033 Citric acid. (a) Product. Citric acid. (b) Conditions of use. This substance is...

  10. Acid Rain: What We Must Do.

    Science.gov (United States)

    Gorham, Eville

    1983-01-01

    Addresses questions about the nature, source, and history of acid rain. In addition, discusses the questions: Why is acid rain a problem? Is acid rain getting worse? What is the threat of further problems? Concludes that it is time to act on the problem and recommends an appropriate course of action. (JN)

  11. Acid Rain. LC Science Tracer Bullet.

    Science.gov (United States)

    Hollmann, Pauline, Comp.

    The term "acid rain," also called "acid precipitation," generally refers to any precipitation having a pH value of less than 5.6. This guide to the literature on acid rain in the collections of the Library of Congress is not necessarily intended to be a comprehensive bibliography. It is designed to provide the reader with a set of resources that…

  12. Acid Rain Students Do Original Research.

    Science.gov (United States)

    Outdoor Communicator, 1984

    1984-01-01

    At Park Senior High School (Cottage Grove, Minnesota), 46 juniors and seniors planted 384 red pine seedlings in connection with their original research on acid rain, with advice from Dr. Harriet Stubbs, director of the Acid Precipitation Awareness Program (West Saint Paul), which has been developing acid rain teaching materials. (MH)

  13. 21 CFR 172.130 - Dehydroacetic acid.

    Science.gov (United States)

    2010-04-01

    ... Food Preservatives § 172.130 Dehydroacetic acid. The food additive dehydroacetic acid and/or its sodium... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Dehydroacetic acid. 172.130 Section 172.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  14. 21 CFR 582.1005 - Acetic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acetic acid. 582.1005 Section 582.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1005 Acetic acid. (a) Product. Acetic acid. (b) Conditions of use. This substance is...

  15. Genetics of proteinases of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan; Venema, Gerhardus

    1988-01-01

    Because it is essential for good growth with concomitant rapid acid production, and for the production of flavorous peptides and amino acids, the proteolytic ability of lactic acid bacteria is of crucial importance for reliable dairy product quality. In view of this importance, considerable research

  16. Amino acid analyses of Apollo 14 samples.

    Science.gov (United States)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Aue, W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

  17. Unnatural reactive amino acid genetic code additions

    Science.gov (United States)

    Deiters, Alexander; Cropp, T. Ashton; Chin, Jason W.; Anderson, J. Christopher; Schultz, Peter G.

    2014-08-26

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  18. Unnatural reactive amino acid genetic code additions

    Energy Technology Data Exchange (ETDEWEB)

    Deiters, Alexander; Cropp, Ashton T; Chin, Jason W; Anderson, Christopher J; Schultz, Peter G

    2013-05-21

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  19. Tranexamic acid for upper gastrointestinal bleeding

    DEFF Research Database (Denmark)

    Gluud, Lise Lotte; Klingenberg, Sarah Louise; Langholz, Ebbe

    2012-01-01

    Tranexamic acid reduces haemorrhage through its antifibrinolytic effects. In a previous version of the present review, we found that tranexamic acid may reduce mortality. The present review includes updated searches of randomised trials on tranexamic acid versus placebo, cimetidine or lansoprazole....

  20. 21 CFR 582.1091 - Succinic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Succinic acid. 582.1091 Section 582.1091 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1091 Succinic acid. (a) Product. Succinic acid. (b) Conditions of use. This substance is...

  1. Dietary arachidonic acid in perinatal nutrition

    DEFF Research Database (Denmark)

    Lauritzen, Lotte; Fewtrell, Mary; Agostoni, Carlo

    2015-01-01

    Arachidonic acid (AA) is supplied together with docosahexaenoic acid (DHA) in infant formulas, but we have limited knowledge about the effects of supplementation with either of these long-chain polyunsaturated fatty acids (LCPUFA) on growth and developmental outcomes. AA is present in similar lev...

  2. Amino acids as antioxidants for frying oil

    Science.gov (United States)

    Amino acids, proteins and hydrolysates of proteins have been known to protect edible oils from oxidation. While amino acids and related materials have high potential as antioxidants for frying oil, effectiveness of each amino acid and mechanisms of their activities are not well understood yet. Propo...

  3. Maastricht essential fatty acid birth cohort

    NARCIS (Netherlands)

    Van der Wurff, Inge; De Groot, Renate; Stratakis, Nikos; Gielen, Marij; Hornstra, Gerard; Zeegers, Maurice

    2016-01-01

    The Maastricht Essential Fatty Acid Birth cohort (MEFAB) was established in 1989 to study the changes in fatty acid concentration during pregnancy and how this related to the fatty acid concentrations of the neonate. The original sample contains data of 1203 subjects. Some participants whom particip

  4. 21 CFR 582.1061 - Lactic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Lactic acid. 582.1061 Section 582.1061 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1061 Lactic acid. (a) Product. Lactic acid. (b) Conditions of use. This substance is...

  5. 21 CFR 556.590 - Salicylic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Salicylic acid. 556.590 Section 556.590 Food and... Residues of New Animal Drugs § 556.590 Salicylic acid. A tolerance of zero is established for residues of salicylic acid in milk from dairy animals....

  6. Solid-state actinide acid phosphites from phosphorous acid melts

    Energy Technology Data Exchange (ETDEWEB)

    Oh, George N. [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Burns, Peter C., E-mail: pburns@nd.edu [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2014-07-01

    The reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})]. This compound crystallizes in space group P2{sub 1}/n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO{sub 2}OH){sub 4} (An=U, Th) and of the mixed acid phosphite–phosphite U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O)·2(H{sub 2}O). α- and β-An(HPO{sub 2}OH){sub 4} crystallize in space groups C2/c and P2{sub 1}/n, respectively, and comprise a three-dimensional network of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O){sub 2}·(H{sub 2}O) crystallizes in a layered structure in space group Pbca that is composed of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized. - Graphical abstract: Reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with DMF produces crystals of (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})] with a layered structure. Reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup and further solution-state reactions result in the crystallization of the actinide acid phosphites An(HPO{sub 2}OH){sub 4} (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite

  7. Docosahexaenoic acid and n-6 docosapentaenoic acid supplementation alter rat skeletal muscle fatty acid composition

    Directory of Open Access Journals (Sweden)

    Lim Sun-Young

    2007-04-01

    Full Text Available Abstract Background Docosahexaenoic acid (22:6n-3, DHA and n-6 docosapentaenoic acid (22:5n-6, DPAn-6 are highly unsaturated fatty acids (HUFA, ≥ 20 carbons, ≥ 3 double bonds that differ by a single carbon-carbon double bond at the Δ19 position. Membrane 22:6n-3 may support skeletal muscle function through optimal ion pump activity of sarcoplasmic reticulum and electron transport in the mitochondria. Typically n-3 fatty acid deficient feeding trials utilize linoleic acid (18:2n-6, LA as a comparison group, possibly introducing a lower level of HUFA in addition to n-3 fatty acid deficiency. The use of 22:5n-6 as a dietary control is ideal for determining specific requirements for 22:6n-3 in various physiological processes. The incorporation of dietary 22:5n-6 into rat skeletal muscles has not been demonstrated previously. A one generation, artificial rearing model was utilized to supply 22:6n-3 and/or 22:5n-6 to rats from d2 after birth to adulthood. An n-3 fatty acid deficient, artificial milk with 18:2n-6 was supplemented with 22:6n-3 and/or 22:5n-6 resulting in four artificially reared (AR dietary groups; AR-LA, AR-DHA, AR-DPAn-6, AR-DHA+DPAn-6. A dam reared group (DAM was included as an additional control. Animals were sacrificed at 15 wks and soleus, white gastrocnemius and red gastrocnemius muscles were collected for fatty acid analyses. Results In all muscles of the DAM group, the concentration of 22:5n-6 was significantly lower than 22:6n-3 concentrations. While 22:5n-6 was elevated in the AR-LA group and the AR-DPAn-6 group, 20:4n-6 tended to be higher in the AR-LA muscles and not in the AR-DPAn-6 muscles. The AR-DHA+DPAn-6 had a slight, but non-significant increase in 22:5n-6 content. In the red gastrocnemius of the AR-DPAn-6 group, 22:5n-6 levels (8.1 ± 2.8 wt. % did not reciprocally replace the 22:6n-3 levels observed in AR-DHA reared rats (12.2 ± 2.3 wt. % suggesting a specific preference/requirement for 22:6n-3 in red

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

    Science.gov (United States)

    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.

  9. SEM ANALYSIS OF THE ACID-ETCHED ENAMEL PATTERNS PROMOTED BY ACIDIC MONOMERS AND PHOSPHORIC ACIDS

    OpenAIRE

    Mirela Sanae Shinohara; Marcelo Tavares de Oliveira; Vinícius Di Hipólito; Marcelo Giannini; Mario Fernando de Goes

    2006-01-01

    ABSTRACT OBJECTIVE: Although self-etching bonding systems (SES) are indicated to prepare dental enamel for bonding, concerns have been expressed regarding their effectiveness. The aim of this study was to analyze the etching pattern (EP) of nine SES in comparison with 35% and 34% phosphoric acid etchants (FA) on intact (IN) and ground (GR) enamel surface. MATERIALS AND METHODS: Twenty-two human third molars were sectioned in mesial-distal and buccal-lingual directions, and four dental fragmen...

  10. Nucleic acid-binding glycoproteins which solubilize nucleic acids in dilute acid: re-examination of the Ustilago maydis glycoproteins

    Energy Technology Data Exchange (ETDEWEB)

    Unrau, P.; Champ, D.R.; Young, J.L.; Grant, C.E.

    1980-01-01

    Holloman reported the isolation from Ustilago maydis of a glycoprotein which prevented the precipitation of nucleic acids in cold 5% trichloroacetic acid. Two glycoprotein fractions from U. maydis with this nucleic acid-solubilizing activity were isolated in our laboratory using improved purification procedures. The activity was not due to nuclease contamination. The glycoproteins are distinguished by: their ability to bind to concanavalin A-Sepharose; their differential binding to double- and single-stranded deoxyribonucleic acid, and to ribonucleic acid; their molecular weights (46,000 and 69,000); and the relative amounts present in growing versus nongrowing cells. Both fractions required sulfhydryl-reducing conditions for optimal yields, specific activity, and stability. Nucleic acid binding was cooperative, the minimum number of glycoproteins required to make a native T7 DNA molecule soluble in dilute acid being estimated at 2 and 15, respectively.

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

    Science.gov (United States)

    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.

  12. Kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid

    NARCIS (Netherlands)

    Girisuta, B.; Janssen, L. P. B. M.; Heeres, H. J.

    2007-01-01

    A variety of interesting bulk chemicals is accessible by the acid-catalyzed hydrolysis of cellulose. An interesting example is levulinic acid, a versatile precursor for fuel additives, polymers, and resins. A detailed kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid is r

  13. Molecular pharmacology of 4-substituted glutamic acid analogues at ionotropic and metabotropic excitatory amino acid receptors

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Nielsen, B; Stensbøl, T B;

    1997-01-01

    The pharmacology of (2S,4R)-4-methylglutamic acid, (2S,4S)-4-methylglutamic acid and (S)- and (R)-4-methyleneglutamic acids (obtained in high chemical and enantiomeric purity from racemic 4-methyleneglutamic acid by chiral HPLC using a Crownpak CR(+) column), was examined in binding experiments u...

  14. Device for the detection of acid vapors and particularly hydrofluoric acid vapors

    International Nuclear Information System (INIS)

    This device concerns the detection of acid vapors contained in a gaseous environment which have to be controlled. It uses a detector with a calorimetric material. It can be used to detect acid vapors, but it detects particularly hydrofluoric acid vapors. In nuclear industry, this device can detect hydrofluoric acid from UF6, even at high temperature. (TEC)

  15. Separation and identification of amino acids from lignite humic acids by thin layer chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Damian, L.; Marutoiu, C.; Niac, G.

    1985-07-01

    Thin layer chromatography with and without temperature gradient was used to identify ten amino acids in the humic acid hydrolysate of Rovinari lignite, using cellulose and volcanic tuff as stationary phases. The acids found were L-leucine, isoleucine, phenylalanine, L-valine, tyrosine, proline, L-alanine, glutamic acid, threonine and L-lysine. 8 references.

  16. Interference effects from coexisting fatty acids on elaidic acid separation by fractionating crystallization: A model study

    DEFF Research Database (Denmark)

    Jala, Ram Chandra Reddy; Guo, Zheng; Bjerring, Thomas;

    2010-01-01

    A multi-stage temperature-programmed fractionating crystallization process was carried out to examine the effects of the presence of stearic acid (SA), oleic acid (OA), and linoleic acid (LA) on the separation of elaidic acid (EA). The results showed that the efficiency of fractionating crystalli...

  17. DOES JASMONIC ACID PREVENT THE GERMINATION

    OpenAIRE

    ÇAVUŞOĞLU, Kürşat

    2009-01-01

    Abstract: Effect of jasmonic acid on seed germination and seedling growth of barley (Hordeum vulgare L. cv. Bülbül 89) was investigated in the present study. Jasmonic acid concentrations less than 1500 µM have not inhibited the seed germination, while 1500 and 2000 µM jasmonic acid levels caused atypical germination. The germination was completely inhibited at 3000 µM level of jasmonic acid. However, the seedling growth clearly slowed down with increasing concentrations of jasmonic acid. Furt...

  18. The Specifications for Monitoring of Acid Rain

    Institute of Scientific and Technical Information of China (English)

    Tang Jie

    2011-01-01

    Background Since China is a country seriously affected by acid rain pollution,it is a long-term fundamental work for acid rain pollution prevention and control in China by getting well informed of the characteristics of spatial and temporal changes in acid rain and long-term trends of these changes.In order to reach the national demand for acid rain monitoring data,the China Meteorological Administration (CMA) began to construct the network of acid rain monitoring stations in 1992.By the end of 2010,the total number of monitoring stations has exceeded 340.

  19. Chicoric acid: chemistry, distribution, and production

    Directory of Open Access Journals (Sweden)

    Jungmin eLee

    2013-12-01

    Full Text Available Though chicoric acid was first identified in 1958, it was largely ignored until recent popular media coverage cited potential health beneficial properties from consuming food and dietary supplements containing this compound. To date, plants from at least 63 genera and species have been found to contain chicoric acid, and while the compound is used as a processing quality indicator, it may also have useful health benefits. This review of chicoric acid summarizes research findings and highlights gaps in research knowledge for investigators, industry stakeholders, and consumers alike. Additionally, chicoric acid identification and quantification methods, biosynthesis, processing improvements to increase chicoric acid retention, and potential areas for future research are discussed.

  20. Formation constants of mixed ligand complexes of oxovanadium(IV) with salicylic acid/5-sulphosalicylic acid/8-hydroxyquinoline-5-sulphonic acid and hippuric acid

    International Nuclear Information System (INIS)

    Equilibrium studies are described on the interaction of oxovanadium(IV) with salicylic acid (SA)/5-sulphosalicylic acid (SSA)/8-hydroxyquinoline-5-sulphonic acid (HQSA) in presence of hippuric acid. The formation of 1:1:1 mixed ligand complexes and their hydroxo derivatives inferred from the pH-metric titration curves and formation constants of 1:1:1 ternary complexes have been evaluated at 30 +- 0.5deg (μ = 0.1 M KNO3). The order of stability of ternary complexes has been found to be the same as that of 1:1 binary complexes involving hydroxy acids. (author)

  1. Bile acids in regulation of intestinal physiology.

    LENUS (Irish Health Repository)

    Keating, Niamh

    2009-10-01

    In addition to their roles in facilitating lipid digestion and absorption, bile acids are recognized as important regulators of intestinal function. Exposure to bile acids can dramatically influence intestinal transport and barrier properties; in recent years, they have also become appreciated as important factors in regulating cell growth and survival. Indeed, few cells reside within the intestinal mucosa that are not altered to some degree by exposure to bile acids. The past decade saw great advances in the knowledge of how bile acids exert their actions at the cellular and molecular levels. In this review, we summarize the current understanding of the role of bile acids in regulation of intestinal physiology.

  2. "Stratifiability index" - A quantitative assessment of acid stratification in flooded lead acid batteries

    Science.gov (United States)

    Schulte, Dominik; Sauer, Dirk Uwe; Ebner, Ellen; Börger, Alexander; Gose, Sven; Wenzl, Heinz

    2014-12-01

    A methodology is presented to quantify acid stratification in flooded lead acid batteries and compare different types of batteries regardless of their design features and size by means of the proposed "stratifiability index". This index describes to what degree acid stratification develops in flooded lead acid batteries. Different test procedures are proposed which induce severe acid stratification within 48 h and lead to significantly different degrees of acid stratification. The test procedures are intended to assist in the development and selection of batteries which are less prone to develop severe acid stratification.

  3. Intestinal transport of sulfanilic acid in rats immunized with protein-sulfanilic acid conjugate.

    Science.gov (United States)

    Yamamoto, A; Kawaratani, T; Kawashima, K; Hashida, M; Sezaki, H

    1990-07-01

    Intestinal transport of sulfanilic acid was examined by means of an in vitro everted sac technique in rats immunized with a bovine gamma-globulin-sulfanilic acid conjugate. At a low concentration of sulfanilic acid, the intestinal transport of sulfanilic acid was decreased in rats immunized with bovine gamma-globulin-sulfanilic acid conjugate. This phenomenon was dose dependent and antigen specific, since there was no difference in the transport of sulfanilic acid at a high concentration and of an unrelated hapten. These results suggested that parenteral immunization impaired not only the intestinal transport of macromolecular antigens, as previously shown, but also the transport of the low molecular weight hapten, sulfanilic acid.

  4. Lactobionic and cellobionic acid production profiles of the resting cells of acetic acid bacteria.

    Science.gov (United States)

    Kiryu, Takaaki; Kiso, Taro; Nakano, Hirofumi; Murakami, Hiromi

    2015-01-01

    Lactobionic acid was produced by acetic acid bacteria to oxidize lactose. Gluconobacter spp. and Gluconacetobacter spp. showed higher lactose-oxidizing activities than Acetobacter spp. Gluconobacter frateurii NBRC3285 produced the highest amount of lactobionic acid per cell, among the strains tested. This bacterium assimilated neither lactose nor lactobionic acid. At high lactose concentration (30%), resting cells of the bacterium showed sufficient oxidizing activity for efficient production of lactobionic acid. These properties may contribute to industrial production of lactobionic acid by the bacterium. The bacterium showed higher oxidizing activity on cellobiose than that on lactose and produced cellobionic acid. PMID:25965080

  5. Current topics in the biotechnological production of essential amino acids, functional amino acids, and dipeptides.

    Science.gov (United States)

    Mitsuhashi, Satoshi

    2014-04-01

    Amino acids play important roles in both human and animal nutrition and in the maintenance of health. Here, amino acids are classified into three groups: first, essential amino acids, which are essential to nutrition; second, functional amino acids, recently found to be important in the promotion of physiological functions; and third, dipeptides, which are used to resolve problematic features of specific free amino acids, such as their instability or insolubility. This review focusses on recent researches concerning the microbial production of essential amino acids (lysine and methionine), functional amino acids (histidine and ornithine), and a dipeptide (L-alanyl-L-glutamine). PMID:24679256

  6. Study of Synthesis of Copoly (lactic acid/glycolic acid) by Direct Melt Polycondensation

    Institute of Scientific and Technical Information of China (English)

    LAN Ping; GAO Qin-wei; SHAO Hui-li; HU Xue-chao

    2005-01-01

    A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/ptoluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.

  7. Evolution of retinoic acid receptors and retinoic acid signaling.

    Science.gov (United States)

    Gutierrez-Mazariegos, Juliana; Schubert, Michael; Laudet, Vincent

    2014-01-01

    Retinoic acid (RA) is a vitamin A-derived morphogen controlling important developmental processes in vertebrates, and more generally in chordates, including axial patterning and tissue formation and differentiation. In the embryo, endogenous RA levels are controlled by RA synthesizing and degrading enzymes and the RA signal is transduced by two retinoid receptors: the retinoic acid receptor (RAR) and the retinoid X receptor (RXR). Both RAR and RXR are members of the nuclear receptor superfamily of ligand-activated transcription factors and mainly act as heterodimers to activate the transcription of target genes in the presence of their ligand, all-trans RA. This signaling pathway was long thought to be a chordate innovation, however, recent findings of gene homologs involved in RA signaling in the genomes of a wide variety of non-chordate animals, including ambulacrarians (sea urchins and acorn worms) and lophotrochozoans (annelids and mollusks), challenged this traditional view and suggested that the RA signaling pathway might have a more ancient evolutionary origin than previously thought. In this chapter, we discuss the evolutionary history of the RA signaling pathway, and more particularly of the RARs, which might have experienced independent gene losses and duplications in different animal lineages. In sum, the available data reveal novel insights into the origin of the RA signaling pathway as well as into the evolutionary history of the RARs. PMID:24962881

  8. Microbial production of citric acid

    Directory of Open Access Journals (Sweden)

    Luciana P. S Vandenberghe

    1999-01-01

    Full Text Available Citric acid is the most important organic acid produced in tonnage and is extensively used in food and pharmaceutical industries. It is produced mainly by submerged fermentation using Aspergillus niger or Candida sp. from different sources of carbohydrates, such as molasses and starch based media. However, other fermentation techniques, e.g. solid state fermentation and surface fermentation, and alternative sources of carbon such as agro-industrial residues have been intensively studied showing great perspective to its production. This paper reviews recent developments on citric acid production by presenting a brief summary of the subject, describing micro-organisms, production techniques, and substrates, etc.O ácido cítrico é o ácido mais produzido em termos de tonagem e é extensivamente utilizado pelas indústrias alimentícia e farmacêutica. É produzido principalmente por fermentação submersa utilizando o fungo Aspergillus niger e leveduras do gênero Candida sp. à partir de diferentes fontes de carbono, como a glicose e meios à base de amido. No entanto, outras técnicas de fermentação, e.g. fermentação no estado sólido e em superfície, e fontes alternativas de carbono tem sido intensamente estudadas mostrando grande perspectivas para o processo. O presente trabalho apresenta um resumo dos últimos avanços sobre a produção do ácido cítrico, descrevendo de maneira sucinta os trabalhos mais recentes, descrevendo microrganismos, técnicas de produção e substratos empregados, etc.

  9. Amino acid properties conserved in molecular evolution.

    Directory of Open Access Journals (Sweden)

    Witold R Rudnicki

    Full Text Available That amino acid properties are responsible for the way protein molecules evolve is natural and is also reasonably well supported both by the structure of the genetic code and, to a large extent, by the experimental measures of the amino acid similarity. Nevertheless, there remains a significant gap between observed similarity matrices and their reconstructions from amino acid properties. Therefore, we introduce a simple theoretical model of amino acid similarity matrices, which allows splitting the matrix into two parts - one that depends only on mutabilities of amino acids and another that depends on pairwise similarities between them. Then the new synthetic amino acid properties are derived from the pairwise similarities and used to reconstruct similarity matrices covering a wide range of information entropies. Our model allows us to explain up to 94% of the variability in the BLOSUM family of the amino acids similarity matrices in terms of amino acid properties. The new properties derived from amino acid similarity matrices correlate highly with properties known to be important for molecular evolution such as hydrophobicity, size, shape and charge of amino acids. This result closes the gap in our understanding of the influence of amino acids on evolution at the molecular level. The methods were applied to the single family of similarity matrices used often in general sequence homology searches, but it is general and can be used also for more specific matrices. The new synthetic properties can be used in analyzes of protein sequences in various biological applications.

  10. Pairwise amino acid secondary structural propensities

    Science.gov (United States)

    Chemmama, Ilan E.; Chapagain, Prem P.; Gerstman, Bernard S.

    2015-04-01

    We investigate the propensities for amino acids to form a specific secondary structure when they are paired with other amino acids. Our investigations use molecular dynamics (MD) computer simulations, and we compare the results to those from the Protein Data Bank (PDB). Proper comparison requires weighting of the MD results in a manner consistent with the relative frequency of appearance in the PDB of each possible pair of amino acids. We find that the propensity for an amino acid to assume a secondary structure varies dramatically depending on the amino acid that is before or after it in the primary sequence. This cooperative effect means that when selecting amino acids to facilitate the formation of a secondary structure in peptide engineering experiments, the adjacent amino acids must be considered. We also examine the preference for a secondary structure in bacterial proteins and compare the results to those of human proteins.

  11. ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIAL ISOLATES

    Directory of Open Access Journals (Sweden)

    Utkarsha S. Shivsharan

    2013-08-01

    Full Text Available Micro-organisms have tendency to produce antimicrobial substances which show biological activity against other kind of micro-organisms. This phenomenon of bacterial antagonism is observed in lactic acid bacteria with competitive advantages. The lactic acid bacteria are commonly present in many fermented products, fruits and milk products. The variety of antimicrobial substances produced by lactic acid bacteria showing good inhibition capacity include production of lactic acid, acetic acid, hydrogen peroxide, carbon dioxide, diacetyl and bacteriocin. Bacteriocins produced by lactic acid bacteria are the subject of intense research because of their antimicrobial activity against food born bacteria such as Listeria monocytogenes, staphylococcus aureus, Bacillus cereus, Clostridium botulinum and several others .Bacteriocins may be bacteriostatic or bactericidal with narrow or broad range of activity. The main of the study was to study the antimicrobial activity of such lactic acid bacterial isolates.

  12. Gluconic acid production by Penicillium puberulum.

    Science.gov (United States)

    Elnaghy, M A; Megalla, S E

    1975-01-01

    Twenty-five Penicillium species isolated from Egyptian soil were examined for their ability to produce gluconic acid in surface culture. Of the eight species capable of producing gluconic acid, Penicillium puberulum gave the maximum yield (91% gluconic acid from glucose after 7 days of fermentation with 3% CaCO3). Peptone was the best nitrogen source for acid fermentation and glucose was superior to sucrose. Addition of low concentrations of KH2PO4 and MgSO4 - 7 H2O stimulated acid production. An initial pH of 6.1 was most favourable for acid accumulation and addition of CaCO3 was necessary for maximum acid production.

  13. The Strongest Acid: Protonation of Carbon Dioxide.

    Science.gov (United States)

    Cummings, Steven; Hratchian, Hrant P; Reed, Christopher A

    2016-01-22

    The strongest carborane acid, H(CHB11F11), protonates CO2 while traditional mixed Lewis/Brønsted superacids do not. The product is deduced from IR spectroscopy and calculation to be the proton disolvate, H(CO2)2(+). The carborane acid H(CHB11F11) is therefore the strongest known acid. The failure of traditional mixed superacids to protonate weak bases such as CO2 can be traced to a competition between the proton and the Lewis acid for the added base. The high protic acidity promised by large absolute values of the Hammett acidity function (H0) is not realized in practice because the basicity of an added base is suppressed by Lewis acid/base adduct formation. PMID:26663640

  14. Nucleic acid delivery with microbubbles and ultrasound.

    Science.gov (United States)

    Rychak, Joshua J; Klibanov, Alexander L

    2014-06-01

    Nucleic acid-based therapy is a growing field of drug delivery research. Although ultrasound has been suggested to enhance transfection decades ago, it took a combination of ultrasound with nucleic acid carrier systems (microbubbles, liposomes, polyplexes, and viral carriers) to achieve reasonable nucleic acid delivery efficacy. Microbubbles serve as foci for local deposition of ultrasound energy near the target cell, and greatly enhance sonoporation. The major advantage of this approach is in the minimal transfection in the non-insonated non-target tissues. Microbubbles can be simply co-administered with the nucleic acid carrier or can be modified to carry nucleic acid themselves. Liposomes with embedded gas or gas precursor particles can also be used to carry nucleic acid, release and deliver it by the ultrasound trigger. Successful testing in a wide variety of animal models (myocardium, solid tumors, skeletal muscle, and pancreas) proves the potential usefulness of this technique for nucleic acid drug delivery. PMID:24486388

  15. Ferrocenyl-phospho-nic acid.

    Science.gov (United States)

    Yang, Bao-Zhang; Xu, Chao; Duan, Tai-Ke; Chen, Qun; Zhang, Qian-Feng

    2011-08-01

    In the title compound, [Fe(C(5)H(5))(C(5)H(6)O(3)P)], the phosphate group is bonded to the ferrocene unit with a P-C bond length of 1.749 (3) Å. In the crystal, six ferrocenyl-phospho-nic acid mol-ecules are connected by 12 strong inter-molecular O-H⋯O hydrogen bonds, leading to the formation of a highly distorted octa-hedral cage. The volume of the octa-hedral cage is about 270 Å(3).

  16. Nanoscale Properties of Boric Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanoscale properties of boric acid were studied by using atomic force microscopy (AFM) and nanome-chanical testing system. XPS was used to research on the transform behaviors of H3BO3 at different temperatures.The crystal structure, surface morphology, and mechanical properties of H3BO3 were described. The results showthat H3BO3 has layered structure, and can be transformed to boron oxide at high temperature. In addition there area lot of defects in H3BO3 crystal.

  17. Direct amidation of amino acid derivatives catalyzed by arylboronic acids : applications in dipeptide synthesis.

    OpenAIRE

    Liu, S.; Yang, Y.; Liu, X.; Ferdousi, F. K.; Batsanov, A.S.; Whiting, A

    2013-01-01

    The direct amidation of amino acid derivatives catalyzed by arylboronic acids has been examined. The reaction was generally slow relative to simple amine-carboxylic acid combinations though proceeded at 65–68 °C generally avoiding racemization. 3,4,5-Trifluorophenylboronic and o-nitrophenylboronic acids were found to be the best catalysts, though for slower dipeptide formations, high catalyst loadings were required and an interesting synergistic catalytic effect between two arylboronic acids ...

  18. Radioprotective activity of folic acid

    International Nuclear Information System (INIS)

    The radioprotective activity of folic acid has been studied using rat liver mitochondria membrane, protein and superoxide dismutase (SOD) as well as pBR 322 plasmid DNA as the model in vitro systems. The vitamin could effectively prevent the γ-ray induced lipid peroxidation as assessed by measuring thiobarbituric acid reactive substrates and protein carbonyl formation effectively. It also could also prevent radiation-induced damage of mitochondrial SOD and restore its level to normalcy Likewise; it prevented radiation-induced DNA strand breaks in a concentration dependent manner. The radioprotective activity could be attributed to its ability to scavenge the hydroxyl and superoxide radicals wherein its pseudo-phenolic moiety and C-9 methylene group play the key role. Radioprotective activity of a polysaccharide preparation from the Indian medicinal plant, Tinospora cordifolia Miers has been established using Saccharomyces cerevisiae X2180 strain as the in vivo test model. The entire activity could be attributed to the radical scavenging capacity of the preparation, as it did not enhance the expression of the protective enzymes, catalase and superoxide dismutase in the yeast cells. (author)

  19. Starch composites with aconitic acid.

    Science.gov (United States)

    Gilfillan, William Neil; Doherty, William O S

    2016-05-01

    The aim of this project is to examine the effectiveness of using aconitic acid (AcA), a tricarboxylic acid which contains a carbon/carbon double bond (CC), to enhance the properties of starch-based films. Starch/glycerol cast films were prepared with 0, 2, 5, 10 and 15wt% AcA (starch wt% basis) and the properties analysed. It was shown that AcA acted as both a cross-linking agent and also a strong plasticising agent. The 5wt% AcA derived starch films were the most effectively cross-linked having the lowest solubility (28wt%) and decreased swelling coefficient (35vol.%) by approximately 3 times and 2.4 times respectively compared to the control film submerged in water (23°C). There was also a significant increase in the film elongation at break by approximately 35 times (compared to the control) with the addition of 15wt% AcA, emphasising the plasticising effect of AcA. However, generally there was a reduced tensile strength, softening of the film, and reduced thermal stability with increased amounts of AcA. PMID:26876996

  20. Pulmonary delivery of nucleic acids.

    Science.gov (United States)

    Birchall, James

    2007-11-01

    The lung is an appropriate present and future target for gene therapy approaches designed to treat inherited monogenic diseases, eradicate bronchial tumours, transfer pharmacologically active products to the general circulation, express enzymes to catabolise toxins, manage pulmonary hypertension and lung injury and vaccinate against infection. Despite 35 years of gene therapy research and some significant milestones in molecular biology, the clinical potential of gene therapy has yet to be realised. In pulmonary gene therapy the nucleic acid cargo needs to be delivered to cells in the target region of the lung, and even in cases when these targets are well defined this is severely limited by the pulmonary architecture, clearance mechanisms, immune activation, the presence of respiratory mucus and the availability of a truly representative biological model. The challenge from a drug delivery perspective is to consider the suitability of conventional nebulisers and inhalers for delivering DNA to the lung and design and apply integrated formulation and device solutions specific to nucleic acid delivery. PMID:17970661