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Propionic Acid (propionic + acid)
Selected Abstracts2,3-Bis(5-alkyl-2-thiono-1,3,5-thiadiazin-3-yl) Propionic Acid: One-Pot Domino Synthesis and Antimicrobial Activity.CHEMINFORM, Issue 22 2005Serry A. A. El Bialy Abstract For Abstract see ChemInform Abstract in Full Text. [source] Stereoselective Michael Addition of Trimethyl Aluminum to Nitro Acrylates: A Route to 2-Methyl-3-amino Propionic Acid.CHEMINFORM, Issue 4 2004Uwe Eilitz Abstract For Abstract see ChemInform Abstract in Full Text. [source] Efficient Synthesis of Halo Indanones via Chlorosulfonic Acid Mediated Friedel,Crafts Cyclization of Aryl Propionic Acids and Their Use in Alkylation Reactions.CHEMINFORM, Issue 21 2007Anil K. Sharma Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Propionic Acids in Organic Synthesis: Novel Synthesis of Benzimidazole, 3,1-Benzoxazine, 3-Aminoquinazoline and 3-Aminothieno[2,3-d]pyrimidine Derivatives Containing 2-Naphthyl Propionyl Moiety.CHEMINFORM, Issue 21 2006Abdullah G. M. Al-Sehemi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Reactive extraction of propionic acid using tri-n-octylamine, tri-n-butyl phosphate and aliquat 336 in sunflower oil as diluentJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2009Amit Keshav Abstract BACKGROUND: Propionic acid is widely used in chemical and allied industries and can be produced by biocultivation in a clean and environmentally friendly route. Recovery of the acid from the dilute stream from the bioreactor is an economic problem. Reactive extraction is a promising method of recovering the acid but suffers from toxicity problems of the solvent employed. There is thus a need for a non-toxic solvent or a combination of less toxic extractants in a non-toxic diluent that can recover acid efficiently. RESULTS: The effect of different extractants (tri-n-butylphosphate (TBP), tri-n-octylamine (TOA) and Aliquat 336) and their mixed binary solutions in sunflower oil diluent was studied to find the best extractant-sunflower oil combination. Equilibrium complexation constant, KE, values of 4.02, 3.13 and 1.87 m3 kmol,1 were obtained for propionic acid extraction using Aliquat 336, TOA and TBP, respectively, in sunflower oil. The effect of different modifiers (1-decanol, methylisobutyl ketone, butyl acetate and dodecanol) on the extraction was also studied and it was found that modifiers enhance extraction, with 1-decanol found to be the best. CONCLUSION: The problem of toxicity in reactive extraction can be reduced by using a non-toxic diluent (sunflower oil) or a modifier in a non-toxic solvent, with the extractant. The addition of modifiers was found to improve the extraction. Copyright © 2008 Society of Chemical Industry [source] Extraction of propionic acid from model solutions: Effect of pH, salts, substrate, and temperatureAICHE JOURNAL, Issue 7 2009Amit Keshav Abstract Propionic acid can be successfully produced from fermentation broth once an efficient recovery method is available for the produced acid. Reactive extraction in this regard is a promising recovery method. pH, salt, substrate, and temperature studies are crucial in the extraction of propionic acid, because these parameters varied in actual fermentation broth. With this regard, effects of these were studied. Extraction from model solutions and salt or substrate containing systems is lower than what was obtained from normal aqueous solutions. Reason of this is the varying degree of hindrances of the salts on extraction of the acid. pH has very large effect on extraction efficiency of the extracting system. At pH > pKa of acid, very low extraction was obtained. Temperature was found to have no effect on the extraction from model solutions used. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Differential induction of LTP and LTD is not determined solely by instantaneous calcium concentration: an essential involvement of a temporal factorEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2001Tomoyuki Mizuno Abstract Two opposite types of synaptic plasticity in the CA1 hippocampus, long-term potentiation (LTP) and long-term depression (LTD), require postsynaptic Ca2+ elevation. To explain these apparently contradictory phenomena, the current view assumes that a moderate postsynaptic increase in Ca2+ leads to LTD, whereas a large increase leads to LTP. No detailed study has so far been attempted to investigate whether the instantaneous Ca2+ elevation level differentially induces LTP or LTD. We therefore used low-frequency (1 Hz) stimulation of Schaffer collateral/commissural fibers in rat hippocampal slices, during a Mg2+ -free period, as the conditioning stimulus to investigate this. This allowed low-frequency afferent stimulation to cause a postsynaptic Ca2+ influx because the voltage-dependent block of N -methyl- d -aspartate (NMDA) receptor-channels by Mg2+ was removed. When delivered during the Mg2+ -free period, a single pulse, as well as 2,600 pulses, induced LTP that was occluded with tetanus-induced LTP. To decrease the Ca2+ influx, ,-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors were completely blocked by the addition of 10 µm 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) to the conditioning medium, in which 1 Hz afferent stimuli (1,600 pulses) induced less LTP and never induced LTD. To further reduce the Ca2+ influx, NMDA receptors were partially blocked with d -(,)-2-amino-5-phosphonopentanoic acid (d -AP5). A small number of 1 Hz stimuli, however, never induced LTD. Only when the conditioning stimuli exceeded 200 pulses was LTD induced. The present findings provide definitive evidence that protracted conditioning is a prerequisite for the induction of LTD. Thus, not only the amplitude but also the duration of postsynaptic Ca2+ elevation could be essential factors for differentially inducing LTP or LTD. [source] Drastic Solid-State Fluorescence Enhancement Behaviour of Phenanthro[9,10- d]imidazole-Type Fluorescent Hosts upon Inclusion of Carboxylic AcidsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 34 2009Yousuke Ooyama Abstract The crystals of phenanthro[9,10- d]imidazole-type fluorescent host 1 exhibit drastic fluorescence enhancement behaviour with a redshift in the emission maximum upon enclathration of various carboxylic acids such as formic acid, acetic acid and propionic acid. The optical changes are greatly dependent on the identity of the enclathrated carboxylic acids. The fluorescent clathrate compounds are formed not only by cocrystallization from carboxylic acid solutions but also by solid (fluorescent host),gas (carboxylic acid vapour) contact. Furthermore, when the acetic acid inclusion crystals are exposed to propionic acid vapour, acetic acid is gradually replaced by propionic acid. The guest exchange of the inclusion crystals was accompanied with colour and fluorescent intensity changes. The X-ray structural analyses of the guest-free and carboxylic acid inclusion compounds demonstrated that the destructions of the ,,, interactions, and the intermolecular hydrogen bonds binding fluorophores were induced by the enclathrated carboxylic acid molecules. Moreover, the imidazole ring of the host is protonated by the enclathrated carboxylic acid proton. On the basis of the spectroscopic data and the crystal structures, the effects of the enclathrated carboxylic acid on the solid-state photophysical properties of the clathrate compounds are discussed.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Exploring the GluR2 ligand-binding core in complex with the bicyclical AMPA analogue (S)-4-AHCPFEBS JOURNAL, Issue 7 2005Bettina B. Nielsen The X-ray structure of the ionotropic GluR2 ligand-binding core (GluR2-S1S2J) in complex with the bicyclical AMPA analogue (S)-2-amino-3-(3-hydroxy-7,8-dihydro-6H -cyclohepta[d]-4-isoxazolyl)propionic acid [(S)-4-AHCP] has been determined, as well as the binding pharmacology of this construct and of the full-length GluR2 receptor. (S)-4-AHCP binds with a glutamate-like binding mode and the ligand adopts two different conformations. The Ki of (S)-4-AHCP at GluR2-S1S2J was determined to be 185 ± 29 nm and at full-length GluR2(R)o it was 175 ± 8 nm. (S)-4-AHCP appears to elicit partial agonism at GluR2 by inducing an intermediate degree of domain closure (17°). Also, functionally (S)-4-AHCP has an efficacy of 0.38 at GluR2(Q)i, relative to (S)-glutamate. The proximity of bound (S)-4-AHCP to domain D2 prevents full D1,D2 domain closure, which is limited by steric repulsion, especially between Leu704 and the ligand. [source] Dramatic Morphology Control in the Fabrication of Porous Polymer Films,ADVANCED FUNCTIONAL MATERIALS, Issue 22 2008Luke A. Connal Abstract Highly ordered, porous honeycomb films are prepared by the breath-figure (BF) technique using dendron-functionalized star polymers as precursors. By changing the nature of the dendritic end groups, dramatically different porous morphologies can be produced. Three series of star polymers are prepared with both the size of the 2,2-bis(methoxy)propionic acid (bis-MPA)-based dendron end group and the dendron functionality being varied. Star polymers end-functionalized with acetonide-protected dendrons (generations 1 to 4) are initially prepared and the acetonide groups subsequently deprotected to yield hydroxyl-functionalized star polymers. Modification of these hydroxyl groups with pentadecafluorooctanoyl chloride yields a third series of functionalized star polymers. The resulting star polymers have surface groups with very different polarity and by utilizing these star polymers to form honeycomb films by the BF technique, the morphology produced is dramatically different. The star polymers with amphiphilic character afford interconnected porous morphologies with multiple layers of pores. The star polymers with pentadecafluorooctanoyl end groups show highly ordered monolayers of pores with extremely thin walls and represent a new porous morphology that has previously not been reported. The ability to prepare libraries of different dendronized star polymers has given further insights into the BF technique and allows the final porous morphology to be controllably tuned utilizing the functional chain ends and generation number of the dendronized star polymers. [source] Fermentation characteristics and aerobic stability of grass silage inoculated with Lactobacillus buchneri, with or without homofermentative lactic acid bacteriaGRASS & FORAGE SCIENCE, Issue 4 2001F. Driehuis Aerobic spoilage by yeasts and moulds is a major cause of reduced nutritional value of silage and increases the risk of potential pathogenic microorganisms. Recent studies have shown that inoculation with Lactobacillus buchneri inhibits yeast growth and reduces the susceptibility to aerobic spoilage of various ensiled forages. The aim of this study was to determine whether these effects are retained when L. buchneri is added in combination with homofermentative lactic acid bacteria. In three experiments, silages were produced from perennial ryegrass [240,421 g kg,1 dry matter (DM)] inoculated with L. buchneri or L. buchneri plus a mixture of Pediococcus pentosaceus and Lactobacillus plantarum (inoculant PL). Uninoculated silage and silage inoculated with PL alone served as controls. Silages were examined for pH and DM loss in the course of ensilage and chemical and microbiological composition and aerobic stability after 3,4 months. L. buchneri plus PL and PL alone increased the initial rate of pH decline. L. buchneri alone and L. buchneri plus PL enhanced aerobic stability and, in general, reduced yeast and mould counts. In addition, these inoculants increased the final pH and DM loss and the concentrations of acetic acid and 1,2-propanediol (or propionic acid and 1-propanol instead of 1,2-propanediol), and decreased the concentration of lactic acid. The effects of L. buchneri on fermentation products increased with decreasing DM content. In silages of less than 270 g kg,1 DM, L. buchneri increased the ammonia-N concentration. It is suggested that this was associated with the relatively high final pH resulting from the high metabolic activity of L. buchneri in these silages. [source] Modulation of Na+ transport across isolated rumen epithelium by short-chain fatty acids in hay- and concentrate-fed sheepJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 11-12 2003S. K. Uppal Summary The effect of increasing concentrations of short-chain fatty acids [SCFA; mixture of the Na+ salts of acetic acid (62.5%), propionic acid (25.0%) and of butyric acid (12.5%)] on Na+ transport of sheep rumen epithelium was studied in vitro. The conventional Ussing chamber method was used for measuring Na+ transport rates (22Na+), short-circuit current (Isc) and tissue conductance (GT) of isolated rumen epithelium. SCFA in the buffer solution on the mucosal side caused a linear increase of Jnet Na+ from 1.14, to 1.22, 1.78 and 2.50 ,eq/cm2/h in hay-fed sheep at 0, 15, 40 and 80 mmol/l SCFA, respectively. In a second study, the effect of higher SCFA concentrations [0 (control), 80, 100 and 120 mmol/l] was investigated with epithelia from two groups of sheep. One group was subjected to hay ad libitum, whereas the other received concentrate feed (800 g/day in equal portions at 7.00 am and 3.00 pm) and hay ad libitum. Epithelia from concentrate-fed sheep again showed a significant (p < 0.05) and linear increase in Jnet Na+ at 80, 100 and 120 mmol/l. However, in hay-fed sheep, the difference in increase among 80, 100 and 120 mmol/l SCFA was not significant, indicating that, above 80 mmol/l SCFA Jms and Jnet exhibit saturation. Moreover, Na+ fluxes (Jms and Jnet) were generally higher in concentrate-fed than in hay-fed sheep at all SCFA concentrations and significant differences were observed at 100 and 120 mmol/l SCFA. The obtained results confirm the effect of SCFA on Na+ transport and are in agreement with studies regarding feeding regimes and electrolyte transport in the rumen. The important new observation is the increase of Na+ transport in concentrate-fed sheep even at high concentrations of SCFA (100 and 120 mmol/l). The enhanced activity of the Na+/H+ exchanger at these SCFA concentrations supports the assumption that the capacity for regulating the intracellular pH by extrusion of protons is increased, suggesting an adaptation in concentrate-fed sheep. This adaptation could prevent possible disturbances of epithelial functions (transport and barrier) under conditions of increased SCFA absorption. [source] Pathways that produce volatile sulphur compounds from methionine in Oenococcus oeniJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2008A. Vallet Abstract Aims:, Determination of pathways involved in synthesis of volatile sulphur compounds (VSC) from methionine by Oenococcus oeni isolated from wine. Methods and Results:, Production of VSC by O. oeni from methionine was investigated during bacterial cultures and in assays performed in the presence of resting cells or protein fractions. Cells of O. oeni grown in a medium supplemented with methionine produced methanethiol, dimethyl disulphide, methionol and 3-(methylthio)propionic acid. Methional was also detected, but only transiently during the exponential growth phase. It was converted to methionol and 3-(methylthio) propionic acid in assays. Although this acid could be produced alternatively from 2-oxo-4-(methylthio) butyric acid (KMBA) by oxidative decarboxylation. In addition, KMBA was a precursor for methanethiol and dimethyl disulphide synthesis. Interestingly, assays with resting cells and protein fractions suggested that a specific enzyme could be involved in this conversion in O. oeni. Conclusion:, This work shows that methional and KMBA are the key intermediates for VSC synthesis from methionine in O. oeni. Putative enzymatic and chemical pathways responsible for the production of these VSC are discussed. Significance and impact of the study:, This work confirms the capacity of O. oeni to metabolize methionine and describes the involvement of potential enzymatic pathways. [source] FTIR, 1H-NMR spectra, and thermal characterization of water-based polyurethane/acrylic hybridsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008O. R. Pardini Abstract Polyurethane (PU) polymer was synthesized following a prepolymer mixing process, by polyaddition of isophorone diisocyanate (IPDI), poly(propylene glycol) (PPG), 2-hydroxyethyl methacrylate (HEMA), and 2,2-bis(hydroxymethyl)propionic acid (DMPA). The PU anionomer having 2-ethoxymethacrylate terminal groups was dispersed in water by prior neutralization of carboxylic acid groups of DMPA with triethylamine (TEA), chain extended with hydrazine (HZM) in water and a dispersion polymerization with methyl methacrylate/n -butyl acrylate/acrylic acid mixture was performed. The above polymerization reactions lead to the formation of PU/acrylic hybrids having a chemical bond between PU and acrylic moieties. Acrylic content was varied from 0 to 50 wt % and samples were purified to eliminate oligomers and impurities before characterization. The FTIR and 1H-NMR spectra of these purified hybrid samples were obtained and bands and peaks assignments were discussed. Thermal properties (DSC and TGA) were also discussed. Breaking hydrogen bonds is the main reason for changes in properties with increasing acrylic content. Particle size data of dispersions is also presented and discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Two cinnamate derivatives produce similar alteration in mRNA expression and activity of antioxidant enzymes in ratsJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 5 2003Mi-Kyung Lee Abstract Cinnamate is a widespread secondary metabolite of phenolic compound synthesized by plants for defensive purposes. The current study was designed to investigate the effect of two structurally related cinnamate derivatives, 4-hydroxycinnamate and 3-(4-hydroxyphenyl)propionic acid (HPP), on the mRNA expression and activity of antioxidant enzymes in high-cholesterol-fed rats. Male rats were fed a 1 g/100 g high-cholesterol diet with supplements of either 4-hydroxycinnamate or HPP (0.135 mmol/100 g diet) for 6 weeks. The plasma paraoxonase activity was found to be higher in the cinnamate-derivative-supplemented groups than in the control group. The erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities, plus glutathione (GSH) level, were all significantly higher in the 4-hydroxycinnamate- and HPP-supplemented groups than in the control group. However, both 4-hydroxycinnamate and HPP supplementation significantly lowered the hepatic activities and mRNA expression of CAT and glutathione peroxidase (GSH-Px) compared to the control group. The hepatic mRNA expression and activity of SOD did not differ between the groups. The hepatic thiobarbituric acid reactive substances (TBARS) level was significantly lowered by the 4-hydroxycinnamate and HPP supplementation. Accordingly, these results indicate that supplementation by 4-hydroxycinnamate and HPP would seem to enhance the antioxidative defense of erythrocyte. Both HPP and 4-hydroxycinnamate would appear to be beneficial in improving the function of antioxidative enzymes on a molecular level in high-cholesterol-fed rats. © 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:255,262, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10087 [source] Reactive extraction of propionic acid using tri-n-octylamine, tri-n-butyl phosphate and aliquat 336 in sunflower oil as diluentJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2009Amit Keshav Abstract BACKGROUND: Propionic acid is widely used in chemical and allied industries and can be produced by biocultivation in a clean and environmentally friendly route. Recovery of the acid from the dilute stream from the bioreactor is an economic problem. Reactive extraction is a promising method of recovering the acid but suffers from toxicity problems of the solvent employed. There is thus a need for a non-toxic solvent or a combination of less toxic extractants in a non-toxic diluent that can recover acid efficiently. RESULTS: The effect of different extractants (tri-n-butylphosphate (TBP), tri-n-octylamine (TOA) and Aliquat 336) and their mixed binary solutions in sunflower oil diluent was studied to find the best extractant-sunflower oil combination. Equilibrium complexation constant, KE, values of 4.02, 3.13 and 1.87 m3 kmol,1 were obtained for propionic acid extraction using Aliquat 336, TOA and TBP, respectively, in sunflower oil. The effect of different modifiers (1-decanol, methylisobutyl ketone, butyl acetate and dodecanol) on the extraction was also studied and it was found that modifiers enhance extraction, with 1-decanol found to be the best. CONCLUSION: The problem of toxicity in reactive extraction can be reduced by using a non-toxic diluent (sunflower oil) or a modifier in a non-toxic solvent, with the extractant. The addition of modifiers was found to improve the extraction. Copyright © 2008 Society of Chemical Industry [source] Effect of changes of pH on the anaerobic/aerobic transformations of biological phosphorus removal in wastewater fed with a mixture of propionic and acetic acidsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2006Yinguang Chen Abstract Most studies on the transformation of enhanced biological phosphorus removal have used acetic acid as the carbon source and focused on the anaerobic phase. In this paper the anaerobic and aerobic transformations of phosphorus removal microorganisms at various pH values were investigated with wastewater containing 3.14 mM C propionic acid and 1.56 mM C acetic acid. It was observed that the influence of acidic pH on the concentrations of mixed-liquor suspended solids and biomass was stronger than that of basic pH, and the maximal cell growth appeared at pH 7.6. The observed uptake rate of propionic acid was much faster than that of acetic acid at all pH values investigated, and both were affected by pH. The anaerobic transformations of polyhydroxyalkanoates and glycogen linearly decreased with increasing pH from 6.6 to 8.6, and a greater glycogen transformation correlated to greater polyhydroxyalkanoate transformation in both anaerobic and aerobic stages. Further studies revealed that at pH 6.6 and 8.6 the overall phosphorus release and uptake was low and there was no net phosphorus removal, although the initial phosphorus release was high. However, when the pH was controlled at pH 7.1 and 7.6, a phosphorus removal efficiency of 97.03% and 96.43% was achieved, respectively, which was greater than that of 87.46% at uncontrolled pH. Copyright © 2006 Society of Chemical Industry [source] Volatile fatty acid production during anaerobic mesophilic digestion of solid potato wasteJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2004Wilson Parawira Abstract The production of volatile fatty acids by anaerobic digestion of solid potato waste was investigated using a batch solid waste reactor with a working capacity of 2 dm,3 at 37°C. Solid potato waste was packed into the digester and the organic content of the waste was released by microbial activity by circulating water over the bed, using batch loads of 500 g or 1000 g potato waste. The sequence of appearance of the volatile fatty acids was (acetic, propionic); (n -butyric); (n -valeric, iso-valeric, caproic); (iso-butyric). After 300 h digestion of potato waste on a small scale, the fermentation products were chiefly (mg g,1 total VFAs): acetic acid (420), butyric acid (310), propionic acid (140) and caproic acid (90), with insignificant amounts of iso-butyric acid, n -valeric and iso-valeric acids. When the load of potato solids was increased, the volatile fatty acid content was similar, but butyric acid constituted 110 mg g,1 and lactic acid 400 mg g,1 of the total volatile fatty acids. The maximum soluble chemical oxygen demand (COD) achieved under the experimental conditions used was 27 and 37 g COD dm,3 at low and high loadings of potato solids, respectively. The total volatile fatty acids reached 19 g dm,3 of leachate at both loads of potato solid waste. Gas production was negligible, indicating that methanogenic activity was effectively inhibited. Copyright © 2004 Society of Chemical Industry [source] Ghanaian Cocoa Bean Fermentation Characterized by Spectroscopic and Chromatographic Methods and ChemometricsJOURNAL OF FOOD SCIENCE, Issue 6 2010Patrick C. Aculey Abstract:, Export of cocoa beans is of great economic importance in Ghana and several other tropical countries. Raw cocoa has an astringent, unpleasant taste, and flavor, and has to be fermented, dried, and roasted to obtain the characteristic cocoa flavor and taste. In an attempt to obtain a deeper understanding of the changes in the cocoa beans during fermentation and investigate the possibility of future development of objective methods for assessing the degree of fermentation, a novel combination of methods including cut test, colorimetry, fluorescence spectroscopy, NIR spectroscopy, and GC-MS evaluated by chemometric methods was used to examine cocoa beans sampled at different durations of fermentation and samples representing fully fermented and dried beans from all cocoa growing regions of Ghana. Using colorimetry it was found that samples moved towards higher,a* and,b* values as fermentation progressed. Furthermore, the degree of fermentation could, in general, be well described by the spectroscopic methods used. In addition, it was possible to link analysis of volatile compounds with predictions of fermentation time. Fermented and dried cocoa beans from the Volta and the Western regions clustered separately in the score plots based on colorimetric, fluorescence, NIR, and GC-MS indicating regional differences in the composition of Ghanaian cocoa beans. The study demonstrates the potential of colorimetry and spectroscopic methods as valuable tools for determining the fermentation degree of cocoa beans. Using GC-MS it was possible to demonstrate the formation of several important aroma compounds such 2-phenylethyl acetate, propionic acid, and acetoin and the breakdown of others like diacetyl during fermentation. Practical Application:, The present study demonstrates the potential of using colorimetry and spectroscopic methods as objective methods for determining cocoa bean quality along the processing chain. Development of objective methods for determining cocoa bean quality will be of great importance for quality insurance within the fields of cocoa processing and raw material control in chocolate producing companies. [source] Fermentation of Cucumbers Brined with Calcium Chloride Instead of Sodium ChlorideJOURNAL OF FOOD SCIENCE, Issue 3 2010Roger F. McFeeters ABSTRACT:, Waste water containing high levels of NaCl from cucumber fermentation tank yards is a continuing problem for the pickled vegetable industry. A major reduction in waste salt could be achieved if NaCl were eliminated from the cucumber fermentation process. The objectives of this project were to ferment cucumbers in brine containing CaCl2 as the only salt, to determine the course of fermentation metabolism in the absence of NaCl, and to compare firmness retention of cucumbers fermented in CaCl2 brine during subsequent storage compared to cucumbers fermented in brines containing both NaCl and CaCl2 at concentrations typically used in commercial fermentations. The major metabolite changes during fermentation without NaCl were conversion of sugars in the fresh cucumbers primarily to lactic acid which caused pH to decrease to less than 3.5. This is the same pattern that occurs when cucumbers are fermented with NaCl as the major brining salt. Lactic acid concentration and pH were stable during storage and there was no detectable production of propionic acid or butyric acid that would indicate growth of spoilage bacteria. Firmness retention in cucumbers fermented with 100 to 300 mM CaCl2 during storage at a high temperature (45 °C) was not significantly different from that obtained in fermented cucumbers with 1.03 M NaCl and 40 mM CaCl2. In closed jars, cucumber fermentations with and without NaCl in the fermentation brine were similar both in the chemical changes caused by the fermentative microorganisms and in the retention of firmness in the fermented cucumbers. [source] Rebamipide enema therapy as a treatment for patients with active distal ulcerative colitisJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2007Ryuichi Furuta Background:, The clinical efficacy of corticosteroids in the treatment of ulcerative colitis (UC) is well-established. However, prolonged usage of these drugs can result in serious complications. Rebamipide {2-(4-chlorobenzoylamino)-3[2-(1H)-quinolinon-4-yl] propionic acid}, a cytoprotective agent, has been reported to have anti-inflammatory activity and to repair mucosal injury in animal colitis models. The aim of the present study was to assess the clinical efficacy and safety of a novel Rebamipide enema therapy in UC patients. Methods:, Twenty patients with the active distal type of UC in whom corticosteroid treatment had been unsuccessful were treated with rectal administration of Rebamipide twice a day for 3 weeks, during which corticosteroid dosage was kept constant. The efficacy of treatment was assessed from clinical symptoms and endoscopic findings. The anti-inflammatory effect of Rebamipide was also examined by monitoring changes in the intensity of histological inflammation and levels of cytokine activity in the rectal mucosa. Results:, At 3 weeks after the initiation of Rebamipide enema therapy, 11 patients (55%) achieved clinical remission. Sixteen (80%) were colonoscopically judged to be responders, with decreased levels of interleukin (IL)-1, but not of IL-8, and an increased ratio of IL-1 receptor antagonist/IL-1, in organ cultures of mucosal tissues. The change in the number of infiltrating neutrophils was not significantly correlated with the clinical response to this therapy. No side-effects were noted in any patients. Conclusion:, Rebamipide enema therapy proved to be safe and useful in corticosteroid-refractory patients with the active distal type of UC. [source] Protective effect of rebamipide on indomethacin-induced intestinal damage in ratsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2001Hiroyuki Mizoguchi Abstract Background and Aim: We evaluated the effect of rebamipide (2-(4-chlorobenzoylamino)-3-[2(1H)-quinolinon-4-yl] propionic acid), a novel anti-ulcer drug, on indomethacin-induced small intestinal lesions in rats. Methods: The animals were administered indomethacin (10 mg/kg, s.c.), and they were killed 24 h later. Rebamipide (30,300 mg/kg) was administered p.o. twice, 30 min before, and 6 h after indomethacin. Results: Indomethacin caused hemorrhagic lesions in the rat small intestine, accompanied by an increase in enterobacterial translocation, inducible nitric oxide synthase (iNOS) and myeloperoxidase (MPO) activities, as well as thiobarbituric acid (TBA) reactants, and these changes were significantly prevented by the supplementation with 16,16-dimethyl prostaglandin E2 (dmPGE2; 10 ,g/kg, i.v.) or the pretreatment of animals with the antibiotic ampicillin. Treatment of the animals with rebamipide dose-dependently prevented the development of intestinal lesions, and this effect was mimicked by i.v. administration of superoxide dismutase (SOD: 3000 U/kg) + catalase (CAT: 5000 U/kg). The protection by rebamipide was accompanied by a significant suppression of the increase in both MPO and iNOS activities, and a complete inhibition of the increase in TBA reactants, while SOD + CAT significantly inhibited the increase of MPO activity and TBA reactants, but not iNOS activity. The bacterial translocation following indomethacin was also significantly decreased by either rebamipide or SOD + CAT. Conclusion: These results confirmed the importance of enterobacteria and iNOS/NO in the pathogenesis of indomethacin-induced small intestinal lesions, and suggested that rebamipide prevents the development of these lesions, probably by its radical scavenging action. [source] Synthesis of 1-substituted 3,5-diaryl-2-pyrazolines by the reaction of ,,,-unsaturated ketones with hydrazinesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2006Albert Lévai 1-Acetyl-, 1-propionyl- and 1-phenyl-3,5-diaryl-2-pyrazolines have been synthesized by the reaction of the appropriate ,,,-unsaturated ketones with hydrazine or phenylhydrazine in hot acetic acid or propionic acid. Structures of all new 2-pyrazolines 16-40 have been elucidated by microanalyses, 1H and 13C nmr spectroscopies. [source] Synthesis and radioiodination of some 9-aminoacridine derivatives for potential use in radionuclide therapyJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 12 2005Senait Ghirmai Abstract Three derivatives of the DNA intercalating compound 9-aminoacridine, were prepared and radioiodinated for biological experiments. The compounds are the stannyl derivatives 3-{4-[3-(acridin-9-ylamino)-propoxy]-3-trimethylstannyl-phenyl}-propionic acid and acridin-9-yl-{3-[4-(2-amino-ethyl)-2-trimethylstannyl-phenoxy]-propyl}-amine which were synthesized from the corresponding iodo derivatives by palladium catalyzed reactions, and 4-[2-(acridin-9-ylamino)-ethyl]-phenol. The two stannylated compounds and the phenol were used as precursors for radioiodination and were labeled with 125I using chloramine-T as an oxidant achieving high-to-excellent yields. Copyright © 2005 John Wiley & Sons, Ltd. [source] Extraction of propionic acid from model solutions: Effect of pH, salts, substrate, and temperatureAICHE JOURNAL, Issue 7 2009Amit Keshav Abstract Propionic acid can be successfully produced from fermentation broth once an efficient recovery method is available for the produced acid. Reactive extraction in this regard is a promising recovery method. pH, salt, substrate, and temperature studies are crucial in the extraction of propionic acid, because these parameters varied in actual fermentation broth. With this regard, effects of these were studied. Extraction from model solutions and salt or substrate containing systems is lower than what was obtained from normal aqueous solutions. Reason of this is the varying degree of hindrances of the salts on extraction of the acid. pH has very large effect on extraction efficiency of the extracting system. At pH > pKa of acid, very low extraction was obtained. Temperature was found to have no effect on the extraction from model solutions used. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Identification of a new functional target of haloperidol metabolite: implications for a receptor-independent role of 3-(4-fluorobenzoyl) propionic acidJOURNAL OF NEUROCHEMISTRY, Issue 2 2006Hyeon Soo Kim Abstract Haloperidol, a dopamine D2 receptor blocker, is a classical neuroleptic drug that elicits extrapyramidal symptoms. Its metabolites include 3-(4-fluorobenzoyl) propionic acid (FBPA) and 4-(4-chlorophenyl)-4-piperidinol (CPHP). Until now, the biological significance of these metabolites has remained largely unknown. Here, we report that the administration of FBPA to mice effected a suppression of locomotor activity and induced catalepsy in a manner similar to that observed with haloperidol, whereas CPHP had no significant effects. Neither of these two metabolites, however, exhibited any ability to bind to the dopamine D2 receptor. FBPA blocked dopamine-induced extracellular signal-regulated kinase 1/2 phosphorylation, and it specifically affected mitogen-activated protein kinase kinase (MEK)1/2 activity in hippocampal HN33 cells. Moreover, FBPA was capable of direct interaction with MEK1/2, and inhibited its activity in vitro. We demonstrated the generation of haloperidol metabolites within haloperidol-treated cells by mass spectrometric analyses. Collectively, our results confirm the biological activity of FBPA, and provide initial clues as to the receptor-independent role of haloperidol. [source] Target-Specific Glutamatergic Regulation of Dopamine Neurons in the Ventral Tegmental AreaJOURNAL OF NEUROCHEMISTRY, Issue 4 2000Ryuichi Takahata Abstract: Dopamine (DA) neurons in the ventral tegmental area (VTA) are thought to play a critical role in affective, motivational, and cognitive functioning. There are fundamental target-specific differences in the functional characteristics of subsets of these neurons. For example, DA afferents to the prefrontal cortex (PFC) have a higher firing and transmitter turnover rate and are more responsive to some pharmacological and environmental stimuli than DA projections to the nucleus accumbens (NAc). These functional differences may be attributed in part to differences in tonic regulation by glutamate. The present study provides evidence for this mechanism: In freely moving animals, blockade of basal glutamatergic activity in the VTA by the selective ,-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate antagonist LY293558 produced an increase in DA release in the NAc while significantly decreasing DA release in the PFC. These data support an AMPA receptor-mediated tonic inhibitory regulation of mesoaccumbens neurons and a tonic excitatory regulation of mesoprefrontal DA neurons. This differential regulation may result in target-specific effects on the basal output of DA neurons and on the regulatory influence of voltage-gated NMDA receptors in response to phasic activation by behaviorally relevant stimuli. [source] Expressions of nitrotyrosine and TUNEL immunoreactivities in cultured rat spinal cord neurons after exposure to glutamate, nitric oxide, or peroxynitriteJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2001Y. Manabe Abstract Although excitotoxic and oxidative stress play important roles in spinal neuron death, the exact mechanism is not fully understood. We examined cell damage of primary culture of 11-day-old rat spinal cord by addition of glutamate, nitric oxide (NO) or peroxynitrite (PN) with detection of nitrotyrosine (NT) or terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL). With addition of glutamate, NOC18 (a slow NO releaser) or PN, immunoreactivity for NT became stronger in the cytoplasm of large motor neurons in the ventral horn at 6 to 48 hr and positive in the axons of the ventral horn at 24 to 48 hr. TUNEL positive nuclei were found in spinal large motor neurons from 24 hr, and the positive cell number greatly increased at 48 hr in contrast to the vehicle. Pretreatment of cultures with ,-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/kainate receptor antagonist, NO-suppressing agent, and antioxidant protected the immunoreactivity for NT or TUNEL. The present results suggest that both excitotoxic and oxidative stress play an important role in the upregulation of NT nitration and the apoptotic pathway in cultured rat spinal neurons. J. Neurosci. Res. 65:371,377, 2001. © 2001 Wiley-Liss, Inc. [source] A strategy for synthesis of ion-bonded amphiphilic miktoarm star copolymers via supramolecular macro-RAFT agentJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2008Dairen Lu Abstract Amphiphilic supramolecular miktoarm star copolymers linked by ionic bonds with controlled molecular weight and low polydispersity have been successfully synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization using an ion-bonded macromolecular RAFT agent (macro-RAFT agent). Firstly, a new tetrafunctional initiator, dimethyl 4,6-bis(bromomethyl)-isophthalate, was synthesized and used as an initiator for atom transfer radical polymerization (ATRP) of styrene to form polystyrene (PSt) containing two ester groups at the middle of polymer chain. Then, the ester groups were converted into tertiary amino groups and the ion-bonded supramolecular macro-RAFT agent was obtained through the interaction between the tertiary amino group and 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid (DMP). Finally, ion-bonded amphiphilic miktoarm star copolymer, (PSt)2 -poly(N -isopropyl-acrylamide)2, was prepared by RAFT polymerization of N -isopropylacrylamide (NIPAM) in the presence of the supramolecular macro-RAFT agent. The polymerization kinetics was investigated and the molecular weight and the architecture of the resulting star polymers were characterized by means of 1H-NMR, FTIR, and GPC techniques. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5805,5815, 2008 [source] Semibatch emulsion polymerization of methyl methacrylate using different polyurethane particlesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2005ebenik Abstract Aqueous acrylic-polyurethane (AC,PU) hybrid emulsions were prepared by semibatch emulsion polymerization of methyl methacrylate (MMA) in the presence of four polyurethane (PU) dispersions. The PU dispersions were synthesized with isophorone diisocyanate (IPDI), 1000 and 2000 molecular weight (MW) poly(neopentyl) adipate, 1000 MW polytetramethyleneetherglycol, butanediol (BD), and dimethylol propionic acid (DMPA). MMA was added in the monomer emulsion feed. We studied the effect of the use of different PU seed particles on the rate of polymerization, the particle size and distribution, the number of particles, and the average number of radicals per particle. The PU rigidity was controlled by varying the polyol chemical structure, the polyol MW (Mn), and by adding BD. The monomer feed rate was varied to study its influence on the process. It was observed that the PU particles that had been prepared with a higher MW polyol swelled better with MMA before the monomer-starved conditions occurred. There seemed to be no significant discrepancies between the series with different PU seeds in the monomer-starved conditions. The overall conversion depended on the monomer addition rate, and the polymerization rate acquired a constant value that was comparable to the value of the monomer addition rate. The instantaneous conversion increased slightly. The average particle size increased, and the total particle number in the reactor was constant and similar to the number of PU particles in the initial charge. The average number of radicals per particle increased. The differences between the system with a constant particle number and average number of radicals per particle and the system with a fixed radical concentration are discussed. The semibatch emulsion polymerization of MMA in the presence of PU particles studied was better compared to the system with a fixed radical concentration. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 844,858, 2005 [source] | ||||||||||||||||||||||||||||||||||||||||