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Adipic Acid (adipic + acid)
Selected AbstractsTransporters involved in apical and basolateral uptake of ceftibuten into Caco-2 cellsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 8 2002Rajeev M. Menon Abstract Ceftibuten uptake from the apical and basolateral side of Caco-2 cells grown on transwells was studied. Uptake into the cells showed concentration dependent saturation. The apical transporter(s) showed a higher capacity and lower affinity for ceftibuten than the basolateral transporter(s). Uptake was inhibited in the presence of higher pH and in the presence of 2,4-dinitro phenol (DNP). A proton gradient had a greater effect on the apical than on the basolateral transporter. Glycyl proline, a dipeptide transport system (PEPT1) substrate, inhibited ceftibuten uptake into Caco-2 cells. Benzoic acid, a monocarboxylic acid (MCT) transporter substrate also exhibited a strong inhibition of ceftibuten uptake, but acetic acid had no effect. Adipic acid inhibited apical uptake of ceftibuten but had no effect on the basolateral uptake. None of the inhibitors had a significant effect on ceftibuten uptake in absence of a pH gradient. Addition of inhibitors in presence of DNP led to a greater decrease in ceftibuten uptake, when compared to the effect of DNP alone, indicating a facilitated diffusion process. These results indicate that ceftibuten uptake in Caco-2 cells involve multiple transport pathways. Apical uptake is mediated by an energy dependent carrier-mediated process and an energy independent facilitated diffusion process. The apical transport system is different from the basolateral transporter. Copyright © 2002 John Wiley & Sons, Ltd. [source] Novel Cadmium(II) Adipate Coordination Polymers with Structural Transformation via Oxalate Ligand: Syntheses, Structures and Fluorescence PropertiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 20 2004Na Hao Abstract Two novel cadmium adipate coordination polymers [Cd{O2C(CH2)4CO2}{1,10-phen}]n (1) and [Cd2(C2O4){O2C(CH2)4CO2(OH2)2}{2,2,-bipy}]·H2O (2) [adipic acid = HO2C(CH2)4CO2H] have been hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. Crystallographic data for 1: monoclinic, C2/c, a = 16.186(3) Å, b = 15.487(3) Å, c = 14.052(3) Å, , = 112.73(3)°, Z = 8. Crystal data for 2: monoclinic, Cc, a = 23.448(5) Å, b = 11.826(2) Å, c = 8.3163(17) Å, , = 99.08(3)°, Z = 4. The structural analysis reveals that 1 forms a novel one-dimensional chain in which the binuclear Cd centers are linked by adipate anions. Compound 2 is the first example in which both a 2,2,-bipy ligand and an oxalate group are found in the {M/adipate} system. Compound 2 possesses one-dimensional sine- or cosine-type chains, which are alternately connected together by the oxalate group to form a three-dimensional framework. The structural determination reveals that the introduction of the oxalate ligand causes the dimensional transformation of the compounds. Compounds 1 and 2 show strong fluorescent properties at room temperature. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] The Coming of Advanced Materials: A Personal View of the Contributions by Cambridge Scientists,ADVANCED MATERIALS, Issue 38-39 2009John Meurig Thomas Abstract The highly significant contributions both directly and indirectly made to the study of condensed matter in general and to advanced materials in particular by a succession of Cambridge scientists over the early years of the past half century are adumbrated in the light of the conjunction of the 21st anniversary of the founding of this journal and the 800th anniversary of the University of Cambridge. So also are the reasons for the burgeoning growth in the last few decades of the preparation, characterization, and use of various kinds of advanced materials. A summary is also given of the author's own work in solid-state and materials science, including a brief appraisal of recent strategies for the design of advanced catalysts for the production (under environmentally benign conditions) of a number of industrially important chemicals ranging from vitamins to commodities, such as adipic acid and terephthalic acid, and building blocks, such as styrene oxide, that are utilized in the manufacture of cosmetics and perfumes. [source] Gellan,adipic acid blends crosslinked by means of a dehydrothermal treatmentJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Niccoletta Barbani Abstract Blends of gellan gum (GE) and adipic acid (ADA), at various ratios, were manufactured in the form of films by casting from aqueous solutions and crosslinked by a dehydrothermal treatment (DHT). The materials, before and after DHT, were characterized by both physicochemical tests and cellular adhesion and growth on the film surfaces. The total reflection and spotlight Fourier transform infrared (FTIR) spectroscopy and optical and scanning electron microscopy showed the presence of both GE-rich and ADA-rich regions and the formation of ester groups after DHT. Differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis (DMA) showed that the crosslinking by DHT made the materials more thermally stable. The swelling in water, which diminished in the films subjected to DHT, confirmed that the crosslinking enhanced the whole stability of the material. DMA also showed that the behavior of the GE,ADA blends was quite similar to that of some living tissues, such as the skin. The cell cultures indicated that the materials, especially that with a 6 : 10 ADA-to-GE ratio, were very able to promote cellular adhesion and proliferation. In conclusion, the GE,ADA crosslinked blends appeared very suitable for a use as biomaterials; in particular, the cell cultures indicated that they might be useful as scaffolds for tissue reconstruction. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Main-chain, thermotropic, liquid-crystalline, hydrogen-bonded polymers of 4,4,-bipyridyl with aliphatic dicarboxylic acidsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2003Pradip K. Bhowmik Abstract A series of main-chain, thermotropic, liquid-crystalline (LC), hydrogen-bonded polymers or self-assembled structures based on 4,4,-bipyridyl as a hydrogen-bond acceptor and aliphatic dicarboxylic acids, such as adipic and sebacic acids, as hydrogen-bond donors were prepared by a slow evaporation technique from a pyridine solution and were characterized for their thermotropic, LC properties with a number of experimental techniques. The homopolymer of 4,4,-bipyridyl with adipic acid exhibited high-order and low-order smectic phases, and that with sebacic acid exhibited only a high-order smectic phase. Like the homopolymer with adipic acid, the two copolymers of 4,4,-bipyridyl with adipic and sebacic acids (75/25 and 25/75) also exhibited two types of smectic phases. In contrast, the copolymer of 4,4,-bipyridyl with adipic and sebacic acids (50/50), like the homopolymer with sebacic acid, exhibited only one high-order smectic phase. Each of them, including the copolymers, had a broad temperature range of LC phases (36,51 °C). The effect of copolymerization for these hydrogen-bonded polymers on the thermotropic properties was examined. Generally, copolymerization increased the temperature range of LC phases for these polymers, as expected, with a larger decrease in the crystal-to-LC transition than in the LC-to-isotropic transition. Additionally, it neither suppressed the formation of smectic phases nor promoted the formation of a nematic phase in these hydrogen-bonded polymers, as usually observed in many thermotropic LC polymers. The thermal transitions for all of them, measured by differential scanning calorimetry, were well below their decomposition temperatures, as measured by thermogravimetric analysis, which were in the temperature range of 193,210 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1282,1295, 2003 [source] Synthesis of new crosslinkable polymers by chemoselective polymerizations of 2-(1-aziridinyl)ethyl methacrylateJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2003Takashi Ishizone The anionic vinyl polymerization of 2-(1-aziridinyl)ethyl methacrylate (1) quantitatively proceeded with diphenylmethylpotassium in the presence of diethylzinc in tetrahydrofuran at ,78 °C for 12 h to form a polymethacrylate (2) with an aziridine ring in each repeating unit. The resulting polymer 2 possessed the predicted molecular weight and narrow molecular weight distribution (weight-average molecular/number-average molecular weight < 1.1) and became readily insoluble by treatment with adipic acid via the crosslinking of the pendant aziridinyl moiety. A poly(ethylene imine) bearing methacryloyl pendant groups was obtained with triethyloxonium tetrafluoroborate via the cationic ring-opening polymerization of 1 in heptane/dichloromethane at 0 °C for 2 h. [source] Hydrolytic Degradation and Monomer Recovery of Poly(butylene succinate) and Poly(butylene succinate/adipate) in the MeltMACROMOLECULAR REACTION ENGINEERING, Issue 6 2008Hideto Tsuji Abstract Aliphatic dicarboxylic acid/aliphatic diol-derived polyesters, poly(butylene succinate) and poly(butylene succinate/adipate), have been hydrolytically degraded in the melt in high-temperature and high-pressure water over a wide temperature range of 180,300,°C for periods of up to 30 min. The formation/decomposition of succinic acid (SA), adipic acid (AA), and butane-1,4-diol (BD), plus the molecular weight change of PBS and PBSA were then investigated. SA and AA were recovered at maximum yields of 65,80%, whereas BD was recovered at a maximum yield of only 30%, probably because of its decomposition. The obtained results were compared with those reported for aliphatic hydroxycarboxylic acid-derived polyesters and aromatic dicarboxylic acid/aliphatic diol-derived polyesters. [source] X-ray studies of crystalline complexes involving amino acids and peptides.ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2006XLIII. The asymmetric unit of the dl -lysine complex of adipic acid [bis(dl -lysinium) adipate], 2C6H15N2O2+·C6H8O42,, contains a zwitterionic singly charged lysinium cation and half a doubly charged adipate anion (the complete anion has inversion symmetry). That of the l -lysine complex (lysinium hydrogen adipate), C6H15N2O2+·C6H9O4,, consists of a lysinium cation and a singly charged hydrogen adipate anion. In both structures, the lysinium cations organize into layers interconnected by adipate or hydrogen adipate anions. However, the arrangement of the molecular ions in the layer is profoundly different in the dl - and l -lysine complexes. The hydrogen adipate anions in the l -lysine complex form linear arrays in which adjacent ions are interconnected by a symmetric O,H,O hydrogen bond. [source] Comparison of ceftibuten transport across Caco-2 cells and rat jejunum mounted on modified ussing chambersBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2003R.M. Menon Abstract Ceftibuten uptake into Caco-2 cells and intestinal brush border membrane vesicles is mediated by the dipeptide transport system (PEPT1). The apical to basolateral transport characteristics of ceftibuten across Caco-2 cells and rat jejunum mounted on a modified Ussing chamber was examined. Mannitol was used as a paracellular marker along with trans-epithelial electrical resistance (TEER) for monitoring tight junction permeability. Transport across Caco-2 cells and rat jejunum mounted on a modified Ussing chamber was linear across the concentration range 0.25,10 mm. The net flux of mannitol and ceftibuten was higher across rat jejunum compared with Caco-2 cells. At a donor concentration of 0.25 mm, ceftibuten transport across Caco-2 cells was found to be pH dependent. Glycyl proline, a dipeptide, and 2,4- dinitrophenol, an energy poison, caused a reduction in the permeability of 0.25 mm ceftibuten across Caco-2 cells. Benzoic acid and adipic acid also inhibited transcellular transport of ceftibuten. At a donor concentration of 0.25 mm, passive paracellular transport accounts for about 60% and the active carrier mediated mechanism accounts for about 40% of ceftibuten transport across Caco-2 cells. None of the inhibitors however, had a significant effect on ceftibuten transport across rat jejunum mounted on a modified Ussing chamber at a donor concentration of 0.25 mm. In the concentration range 0.25,10 mm, ceftibuten is predominantly transported by paracellular mechanisms across rat jejunum and a mixture of active and passive transport across Caco-2 cells. Copyright © 2003 John Wiley & Sons, Ltd. [source] Lipase-catalyzed dimethyl adipate synthesis: Response surface modeling and kineticsBIOTECHNOLOGY JOURNAL, Issue 8 2010Naz Chaibakhsh Abstract Dimethyl adipate (DMA) was synthesized by immobilized Candida antarctica lipase B-catalyzed esterification of adipic acid and methanol. To optimize the reaction conditions of ester production, response surface methodology was applied, and the effects of four factors namely, time, temperature, enzyme concentration, and molar ratio of substrates on product synthesis were determined. A statistical model predicted that the maximum conversion yield would be 97.6%, at the optimal conditions of 58.5°C, 54.0 mg enzyme, 358.0 min, and 12:1 molar ratio of methanol to adipic acid. The R2 (0.9769) shows a high correlation between predicted and experimental values. The kinetics of the reaction was also investigated in this study. The reaction was found to obey the ping-pong bi-bi mechanism with methanol inhibition. The kinetic parameters were determined and used to simulate the experimental results. A good quality of fit was observed between the simulated and experimental initial rates. [source] Production of a Polyester Degrading Extracellular Hydrolase from Thermomonospora fuscaBIOTECHNOLOGY PROGRESS, Issue 5 2002Mona K. Gouda The production of a polyester-degrading hydrolase from the thermophilic actinomycete Thermomonospora fusca was investigated with regard to its potential technical application. Only in the presence of a polyester (random aliphatic-aromatic copolyester from 1,4-butanediol, terephthalic acid, and adipic acid with around 40,50 mol % terephthalic acid in the acid component), the excretion of the extracellular enzyme could be achieved with an optimized synthetic medium using pectin and NH4Cl as nitrogen source. Compared to complex media, a significantly higher specific activity at comparable volumetric yields could be obtained, thus reducing the expenditure for purification. The activity profile in the medium is controlled by a complex process involving (1) induction of enzyme excretion, (2) enzyme adsorption on the hydrophobic polyester surface, (3) inhibition of enzyme generation by monomers produced by polyester cleavage, and (4) enzyme denaturation. Diafiltration with cellulose acetate membranes as the sole downstream processing step led to a product of high purity and with sufficient yield (60% of total activity). Scaling-up from shaking flasks to a fermentor scale of 100 L revealed no specific problems. However, the excretion of the hydrolase by the actinomycete turned out to be inhibited by the degradation products (monomers) of the aliphatic-aromatic copolyester used as inductor for the enzyme production. The crude enzyme exhibited generally similar properties (temperature and pH optimum) as the highly purified hydrolase described previously; however, the storage capability and thermal stability is improved when the crude enzyme solution is diafiltrated. [source] Hydrolysis of Adiponitrile in Near-critical WaterCHINESE JOURNAL OF CHEMISTRY, Issue 9 2008Pei-Gao DUAN Abstract Hydrolysis of adiponitrile (ADN) in near-critical water was successfully conducted in a batch reactor. Influences of m(AND)/m(water) ratio, temperature, time, m(AND)/m(additive) ratio, kind of additive and pressure on the yield of each product were investigated. Five compounds resulting from the hydrolysis of ADN, including 5-cyanovaleramide, adipamide, adipamic acid, adipic acid and trace of 5-cyanovaleric acid, were detected by high performance liquid chromatography. The results showed that change of ADN concentration and temperature had significant influences on the yields of adipamide, adipamic acid and adipic acid; time was the significant factor for the yield of 5-cyanovaleric acid; and the yield of 5-cyanovaleramide was more dependent on the ADN concentration. [source] Synthesis and Characterization of Poly(butylene adipate- co - terephthalate) Catalyzed by Rare Earth StearatesCHINESE JOURNAL OF CHEMISTRY, Issue 10 2007Kui ZHU Abstract Rare earth (Nd, Y, La, Dy) stearates have been synthesized and used as single component catalysts for the polycondensation of dimethyl terephthalate, adipic acid and 1,4-butanediol for the first time preparing biodegradable poly(butylene adipate- co -terephthalate) (PBAT) with high molecular weight. The microstructures of PBAT were characterized by 1H NMR spectra. The PBAT exhibits good mechanical properties such as high tensile strength (ca. 20 MPa) and long break elongation (>700%). [source] Synthesis and specific biodegradation of novel polyesteramides containing amino acid residuesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2001Yujiang Fan Abstract Novel polyesteramides were synthesized from p -nitrophenyl esters of sebacic or adipic acids and diamines containing ,-amino acid ester groups. The optimal polymerization condition was 60 °C in N,N -dimethylformamide. The structures of these polymers were confirmed by IR and NMR. The number-average molecular weights of these polyesteramides ranged from 2280 to 23,600 (except for the polymers containing glycine residues), depending on the nature of the amino acid used. The biodegradability of the polyesteramides was investigated by in vitro hydrolysis with proteases and a lipase as catalysts in borate buffer solutions. The results indicated that the polymers containing L -phenylalanine were hydrolyzed most effectively by ,-chymotrypsin, subtilisin Carlsberg, and subtilisin BPN,. The polyesteramides containing other amino acid residues also underwent hydrolysis to different extents, reflecting the substrate specificity of the proteases. Lipase had almost no effect on the hydrolytic degradation of these polyesteramides. The polymers containing glycine residues were hardly decomposed by any of the enzymes used. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1318,1328, 2001 [source] | ||||||||||||||||