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Acid Concentration (acid + concentration)
Kinds of Acid Concentration Selected AbstractsHistometric and Histochemical Analysis of the Effect of Trichloroacetic Acid Concentration in the Chemical Reconstruction of Skin Scars MethodDERMATOLOGIC SURGERY, Issue 10 2006SUNG BIN CHO MD BACKGROUND Atrophic scars can be induced by various causes, including severely inflamed acne, chicken pox, and trauma. Many treatment modalities are used for reconstructing and improving the appearance of scars with various treatment results. OBJECTIVE A recent report shows the clinical efficacy of the chemical reconstruction of skin scars (CROSS) method, which consists of the focal application of trichloroacetic acid (TCA) in a higher concentration. Histometric analysis of the CROSS method, however, has not yet been established. METHODS In this study, five hairless mice were used to evaluate the effect of the CROSS method and to analyze the difference between the CROSS method and simple TCA application. RESULTS Similar histologic changes were observed in the two methods, including epidermal and dermal rejuvenation with new collagen deposition. These changes, however, were more prominent in the CROSS method,treated areas, particularly when 100% TCA was used. CONCLUSION The results of this study suggest that treatment of atrophic scars using the CROSS method is more effective than simple application of TCA in activating fibroblasts in the dermis and increasing the amount of collagen. [source] Tail Muscle Free Amino Acid Concentration of Pacific White Shrimp, Litopenaeus vannamei, Fed Diets Containing Protein-bound versus Crystalline Amino AcidsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2009Joe M. Fox Tail muscle tissue free amino acids (FAA) concentration is reported for subadult (4.3 g) Litopenaeus vannamei fed diets containing only protein-bound amino acids, crystalline lysine as a supplement to protein-bound lysine, and only crystalline amino acids (CAA). FAA were determined in shrimp at 0.00, 0.25, 0.5, 1, 2, 4, and 8 h postfeeding. Highest total tissue concentrations of essential amino acids and individual amino acids were typically observed 4 h postfeeding for shrimp fed intact and crystalline lysine-supplemented feeds. Those shrimp offered diets containing only CAA showed no tissue maxima. Similar uptake patterns for lysine shown by shrimp fed the intact and crystalline lysine-supplemented diet indicate the potential use of small amounts of crystalline lysine in shrimp feeds. [source] Epidemiological Association between Uric Acid Concentration in Plasma, Lipoprotein(a), and the Traditional Lipid ProfileCLINICAL CARDIOLOGY, Issue 2 2010Giuseppe Lippi MD Abstract Background Elevated levels of uric acid in serum (SUA) or plasma (PUA) are increasingly related to cardiovascular disease. It is unclear whether they are independent risk factors or simply markers, reflecting association with other traditional risk factors. Methods We retrospectively assessed results of a lipid profile, including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, total cholesterol to HDL-C ratio (TC/HDL-C), the atherogenic index of plasma (AIP), and lipoprotein(a) (Lp[a]), in a large cohort of unselected adult outpatients. Results Hyperuricemic men displayed significantly increased values of triglycerides and AIP when compared with men with normal PUA levels. In hyperuricemic women, significant differences were observed for HDL-C, triglycerides, TC/HDL-C, and AIP compared with women with normal PUA levels. The percentage of patients with unfavorable values was statistically higher for triglycerides and AIP in hyperuricemic men; for HDL-C, triglycerides, TC/HDL-C, and AIP in hyperuricemic women. In multivariable linear regression analysis triglycerides, AIP, and TC/HDL-C were independently associated with PUA in women, whereas no significant association was observed in men. Conclusion PUA measurement might be advisable in patients to identify those at increased risk of cardiovascular disease (CVD) who might benefit from further triage and intervention. Copyright © 2010 Wiley Periodicals, Inc. [source] Plasma Homocysteine, B Vitamins, and Amino Acid Concentrations in Cats with Cardiomyopathy and Arterial ThromboembolismJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2000M.A. McMichael Arterial thromboembolism (ATE) is a common complication of cats with cardiomyopathy (CM), but little is known about the pathophysiology of ATE. In people, high plasma concentrations of homocysteine and low B vitamin concentrations are risk factors for peripheral vascular disease. In addition, low plasma arginine concentrations have been linked to endothelial dysfunction. The purpose of this study was to compare concentrations of homocysteine, B vitamins, and amino acids in plasma of normal cats to those of cats with CM and ATE. Plasma concentrations of homocysteine, vitamin B6, vitamin B12, folate, and amino acids were measured in 29 healthy cats, 27 cats with CM alone, and 28 cats with both CM and ATE. No differences were found between groups in homocysteine or folate. Mean vitamin B12 concentration (mean ± standard deviation) was lower in cats with ATE (866 ± 367 pg/mL) and cats with CM (939 ± 389 pg/mL) compared with healthy controls (1,650 ± 700 pg/mL; P < .001). Mean vitamin B6 concentration was lower in cats with ATE (3,247 ± 1,215 pmol/mL) and cats with CM (3,200 ± 906 pmol/mL) compared with healthy control animals (4,380 ± 1,302 pmol/mL; P= .005). Plasma arginine concentrations were lower in cats with ATE (75 ± 33 nmol/mL) compared with cats with CM (106 ± 25 nmol/mL) and healthy control animals (96 ± 25 nmol/ mL; P < .001). Vitamin B12 concentration was significantly correlated with left atrial size. We interpret the results of this study to suggest that vitamin B12 and arginine may play a role in CM and ATE of cats. [source] Serum Bile Acids Concentrations in Healthy and Clinically III Neonatal FoalsJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2007Michelle Henry Barton Background:Reference ranges for serum bile acids (SBA) concentration are well established in healthy adult horses. Increased values are indicative of hepatic disease. Hypotheses: SBA concentrations are significantly greater in the neonatal period compared with mature horses, and illness in the neonatal period will further increase SBA. Animals:Ten healthy mature horses, 12 healthy foals, and 31 clinically ill foals. Methods:Prospective cross-sectional study. Blood samples were obtained once from the mature horses, from healthy foals immediately after birth, at 2 days, and at 1, 2, 3, 4, and 6 weeks of age; and from ill foals less than 1 month of age at the time of admission to the Veterinary Teaching Hospital. SBA concentrations were determined enzymatically and by radioimmunoassay. Total and direct bilirubin and triglyceride concentrations were measured, as well as sorbitol dehydrogenase (SDH) and ,-glutamyltransferase (GGT) activities. Results:There was a significant negative correlation between age and SBA concentration. Compared with mature horses, SBA concentrations were significantly greater in healthy foals at each collection time over the first 6 weeks of life. Radioimmunoassay values were lower than enzymatic SBA values, with increasing bias as the mean difference between values increased. When comparing age-matched values between healthy and ill foals, there were no significant differences in SBA. None of the ill foals had a primary diagnosis of hepatic disease. There was no significant correlation between the SBA concentration and the bilirubin or triglyceride concentrations or the GGT activity. There was a significant direct correlation between increased SBA and serum SDH activity in healthy foals only. Conclusion and Clinical Importance: SBA concentrations in foals are significantly higher in the early neonatal period, underscoring the importance of using age-matched references when evaluating clinical pathology values during the neonatal period. [source] Influence of citric acid on calcium sulfate dihydrate crystallization in aqueous mediaCRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2007S. Titiz-Sargut Abstract The crystallization of Calcium sulfate dihydrate produced by the reaction between pure Ca(OH)2 suspension and H2SO4 solution was investigated at different pH values, temperatures and citric acid concentrations. Crystal size distributions, filtration rates and zeta potentials of gypsum were determined as a function of citric acid concentrations at pH 3.5 and 65°C. The influence of citric acid on the morphology of gypsum was also investigated and discussed. The average particle size of gypsum was reached to maximum in the presence of approximately 2500 ppm citric acid concentration, where the minimum cake resistance and maximum filtration rate were obtained. In the presence of citric acid, various crystal morphologies such as tabular, plate-like, double-taper leaf-like and flower-like, etc., were obtained. The change of morphology is related to the preferential adsorption of citric acid on different crystallographic faces. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Abnormal myelin formation in rhizomelic chondrodysplasia punctata type 2 (DHAPAT-deficiency)DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 7 2000László Sztriha MD PhD The case of a Yemeni girl with isolated peroxisomal acyl-CoA:dihydroxyacetonephosphateacyltransferase (DHAPAT) deficiency is reported. She had rhizomelic chondrodysplasia punctata, microcephaly, failure to thrive, delayed motor and mental development, and spastic quadriplegia. Deficient de novo plasmalogen synthesis in her fibroblasts as a result of low DHAPAT activity was found, while her very-long-chain fatty acid profile, phytanic acid concentration, alkyl-dihydroxyacetonephosphate synthase (alkyl-DHAP synthase) activity, and peroxisomal 3-ketoacyl-CoA thiolase protein were normal. A mutation in her DHAPAT complementary DNA resulted in the substitution of an arginine residue in the protein at position 211 by a histidine (R211H). Magnetic resonance imaging showed abnormal white matter signal in the centrum semiovale involving the arcuate fibers, while the corpus callosum was normal. DHAPAT and alkyl-DHAP synthase initiate the synthesis of plasmalogens, which are major constituents of myelin phospholipids. The reported girl's abnormal formation of myelin is probably related to the inadequacy of plasmalogen biosynthesis, which is likely to be due to deficient DHAPAT activity. [source] Reflux and pH: ,alkaline' components are not neutralized by gastric pH variationsDISEASES OF THE ESOPHAGUS, Issue 1 2000P. Bechi The ability of the ,alkaline' components of reflux to cause harm in vivo is still open to debate, although these components have been shown in vitro to be capable of damaging the mucosa. The precipitation of bile acids and lysolecithin that occurs at low pH values is the main reason for questioning in vivo mucosal damage. This study was undertaken to determine the composition of gastric aspirates at different original pH values and the degree of solubility of the alkaline components when pH modifications are artificially induced. The samples for chemical analysis were collected from indwelling nasogastric tubes after surgical procedures that did not involve the upper gastrointestinal tract. Bile acid and lysolecithin concentrations were assessed by means of dedicated methods. Thirty-five samples were available for bile acid evaluation and 27 for lysolecithin evaluation. Bile acid and lysolecithin assessments were repeated after pH adjustment at 2, 3.5, 5.5 and 7. For easier assessment of the results, three ranges of the original pH were selected (pH,<,2, 2 , pH < 5, pH , 5). For each pH range, results were pooled together and compared with those in the other pH ranges. Bile acid concentrations were 113 ± 48, 339 ± 90 and 900 ± 303 (mean ± s.e.m. ,mol/L), respectively, in the three groups selected on account of the different original pH values. Differences were significant (p < 0.001). Both taurine- and glycine-conjugated bile acids were represented even at pH < 2. No major differences were observed in bile acid concentration with the artificially induced pH variations. Lysolecithin concentrations were 5.99 ± 3.27, 30.80 ± 8.43 and 108.37 ± 22.17 (mean ± SEM ,g/ml), respectively, in the three groups selected on account of the different original pH ranges. Differences were significant (p < 0.001). No significant differences in lysolecithin concentration were detected with the artificially induced pH variations. In conclusion, both bile acids and lysolecithin are naturally represented in the gastric environment even at very low pH values, although their concentrations decrease on lowering of the naturally occurring pH. Given the concentration variability of bile acids and lysolecithin, further studies are needed to assess the minimal concentration capable of mucosal damage in vivo. [source] Augmentation of all- trans -retinoic acid concentration in plasma by preventing inflammation responses induced by atRA-loaded microspheres with concurrent treatment of dexamethasoneDRUG DEVELOPMENT RESEARCH, Issue 4 2004Kyeongsoon Park Abstract All- trans retinoic acid (atRA)-loaded microspheres severely induce inflammatory responses after microsphere implantation. Fibroblasts and a thick band of fibrous capsule resulting from the inflammatory responses could hamper drug permeation to the bloodstream because fibroblasts actively metabolize atRA into polar metabolites and the thick fibrous capsule acts as a diffusion barrier. In the present study, we investigated whether the fibroblast proliferation and collagen deposition induced by atRA released from microspheres might affect the atRA concentration in plasma and atRA metabolism with or without treatment of dexamethasone as an anti-inflammatory drug. After subcutaneous injection of atRA-loaded microspheres in rats, it was observed that atRA-loaded microspheres induced severe inflammatory responses and stimulated fibroblast proliferation and collagen deposition in fibrous capsules. On the other hand, the orally treated dexamethasone effectively prevented inflammatory responses in a dose-dependent manner and suppressed about 49% of the number of fibroblasts and collagen deposition in fibrous capsules at 14 days. In addition, after the treatment of dexamethasone, the atRA concentration in plasma was increased, and its metabolism was decreased approximately by 40% at 7 days, compared to the group treated alone with atRA-loaded microspheres. In conclusion, the concurrent treatment of dexmethasone with atRA-loaded microspheres could prevent inflammatory responses and metabolism of atRA, thereby maintaining the atRA concentration in plasma for longer periods in the therapeutic range. Drug Dev. Res. 61:197,206, 2004. © 2004 Wiley-Liss, Inc. [source] Flexibility in the composition and concentration of amino acids in honeydew of the drepanosiphid aphid Tuberculatus quercicolaECOLOGICAL ENTOMOLOGY, Issue 6 2002Izumi Yao Abstract 1. Mutualistic interactions between aphids and ants are mediated by honeydew that aphids produce. Previous work showed that when attended by the ant Formica yessensis Forel (Hymenoptera: Formicidae), nymphs of the aphid Tuberculatus quercicola (Matsumura) (Homoptera: Aphididae) developed into significantly smaller adults with lower fecundity than did nymphs that were not ant attended. 2. This study tested the hypothesis that this cost of ant attendance arises through changes in the quality and quantity of honeydew. Ant-attended and ant-excluded aphid colonies were prepared in the field. The composition and concentration of amino acids were compared between the honeydew produced by ant-attended colonies and that produced by ant-excluded colonies. 3. The aphids excreted smaller droplets of honeydew, but also excreted them more frequently, in ant-attended colonies than in ant-excluded colonies. The honeydew of ant-attended aphids contained more types of amino acid, and a significantly higher total concentration of amino acids, than did the honeydew of ant-excluded aphids. 4. These results suggest that the increase in the concentration of amino acids in honeydew leads to a shortage of nitrogen available for aphid growth and reproduction, resulting in lower performance under ant attendance. 5. With the advance of seasons, a significant reduction was found in both the total free amino acid concentration in phloem sap and the frequency of honeydew excretion; however the total concentration of amino acids in the honeydew did not vary significantly during the seasons, suggesting that aphids keep the quality of honeydew constant in order to maintain ant visitation. [source] New Methylene Blue (NMB) Encapsulated in Mesoporous AlMCM-41 Material and Its Application for Amperometric Determination of Ascorbic Acid in Real SamplesELECTROANALYSIS, Issue 15 2007Shabnam Sohrabnezhad Abstract New methylene blue (NMB) dye incorporated into AlMCM-41 surfactant-free and hybrid surfactant-AlMCM-41 mesophase. UV-vis evidence shows that new methylene blue dye protonated in both cases of zeolites. New methylene blue is electroactive in zeolites and their electrochemical activity has been studied by cyclic voltammetry and compared to that of NMB in aqueous solutions. New methylene blue molecules are not released to the solution during CV measurements and are accessible to H3O+ ions. The presence of surfactant affects the kinetics of the redox process through proton ions diffusion. The midpoint potentials (Em) values show that new methylene blue dye incorporated into AlMCM-41 can be reduced easily with respect to solution new methylene blue. New methylene blue interacting with surfactant polar heads and residual Br, ions as a results, it shows a couple of peaks in high potential with respect to new methylene blue solution. The electrode made with methylene blue-AlMCM-41 without surfactant was used for the mediated oxidation of ascorbic acid. The anodic peak current observed in cyclic voltammetry was linearly dependent on the ascorbic acid concentration. The calibration plot was linear over the ascorbic acid concentration range 1.0×10,5 to 5.0×10,4 M. The detection limit of the method is 1.0×10,5 M, low enough for trace ascorbic acid determination in various real samples. [source] Highly Sensitive and Selective Measurement of Bismuth in Seawater and Drug with 1,2-Phenylenedioxydiacetic Acid by Cathodic Adsorptive Stripping VoltammetryELECTROANALYSIS, Issue 7 2006B. Gholivand Abstract A new method is presented for determination of bismuth based on cathodic adsorptive stripping of complex bismuth with 1,2-phenylenedioxydiacetic acid (PDA) at a hanging mercury drop electrode (HMDE). The effect of various parameters such as pH, concentration of ligand, accumulation potential and accumulation time on the selectivity and sensitivity were studied. The optimum conditions for determination of bismuth include nitric acid concentration 0.01,M, 8.0×10,4,M PDA and accumulation time 120,s, accumulation potential of ,200,mV. The limits of detection are 0.25 and 0.05,nM, and responses are linear 1,1000 and 0.1,400,nM at tacc of 60 and 120,s, respectively. Many common anions and cations do not interfere in the determination of bismuth. The method was applied to the determination of bismuth in some real samples such as sea , and spring water and drug. [source] Simultaneous Determination of Copper and Bismuth by Anodic Stripping Voltammetry Using H-Point Standard Addition Method with Simultaneous Addition of AnalytesELECTROANALYSIS, Issue 17 2005Esmaeil Shams Abstract Simultaneous determination of bismuth and copper by anodic stripping voltammetry using H-point standard addition method (HPSAM) with simultaneous addition of analytes is described. The effect of various parameters including acid concentration, accumulation time, accumulation potential and concentration ratio of analytes in the standard solution on the sensitivity and accuracy of method were investigated. The results of applying the H-point standard addition method showed that Cu2+ and Bi3+ could be determined simultaneously with the concentration ratios of Cu2+ to Bi3+ varying from 1,:,15 to 16,:,1 in the mixed sample. The method was successfully applied to the simultaneous determination of copper and bismuth in some synthetic mixtures. [source] Association of serum sialic acid and MMP-9 with lipids and inflammatory markersEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2 2000Kalela Background Inflammation of the arterial wall has emerged to be an important contributor to the process of atherosclerosis, the major cause of coronary heart disease. Several factors are currently under investigation as inflammatory markers of atherosclerosis. Serum sialic acid and matrix metalloproteinase-9 may provide such markers. We studied their association with the lipid profile and with the inflammatory markers C-reactive protein and leukocyte count in a clinically healthy population of men. Materials and methods Cardiovascular risk-related laboratory tests were carried out in 65 consecutive male employees in connection with an occupational health survey in 1996. The subjects were divided into tertiles on the basis of serum sialic acid or matrix metalloproteinase-9 concentration. Results In a stepwise polychotomous logistic regression model adjusting for coronary heart disease risk factors, serum sialic acid concentration was not associated with markers of inflammation but rather with the lipid risk factors of atherosclerosis: inversely with HDL cholesterol (OR = 0.081, 95% CI 0.0068,0.97) and positively with total cholesterol (OR = 2.4, 95% CI 1,5.6). Matrix metalloproteinase-9 levels had a significant positive correlation with the leukocyte count (OR = 2.3, 95% CI 1.4,4). Conclusions Serum sialic acid does not appear to be an indicator of inflammation but is somehow connected with the level of total and HDL cholesterol. Serum matrix metalloproteinase-9 may provide a useful marker of inflammation because it correlates with the leukocyte count and is not associated with the lipid profile. [source] One-Pot Synthesis of Core-Modified Rubyrin, Octaphyrin, and Dodecaphyrin: Characterization and Nonlinear Optical PropertiesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 27 2007Rajeev Kumar Abstract Modified 26, rubyrin, 36, octaphyrin, and 54, dodecaphyrin systems have been synthesized in moderately good yields through acid-catalyzed condensations of terthiophene diols and tripyrranes. The product distributions are decided both by the acid catalyst concentration and by the nature of the meso substituents. For example, a new isomer of [26]hexaphyrin(1.1.1.1.0.0) (rubyrin) was obtained with 0.3 equiv. of p -toluenesulfonic acid, when the meso substituent was mesityl in at least one of the precursors. A change of the mesityl substituent for a p -methoxy substituent in terthiophene diol resulted in the formation of a [3,+,3,+,3,+,3] condensation product , [54]dodecaphyrin(1.1.1.1.0.0.1.1.1.1.0.0) , in addition to the expected rubyrin. Furthermore, an increase in the acid concentration to 0.6 equiv. resulted in the formation of a new [36]octaphyrin(1.1.1.1.1.1.0.0), in addition to the rubyrin and dodecaphyrin. A single-crystal X-ray analysis of octaphyrin represents the first example of a planar conformation of an octaphyrin with six meso links. In rubyrin 19, one thiophene ring, opposite to the terthiophene subunit, is inverted, while in octaphyrin 30 one pyrrole ring and two thiophene rings are inverted. The various conformational possibilities tested for the unsubstituted dodecaphyrin 28, at semiempirical level, suggest that the most stable conformation is a figure-eight. The final geometry optimization of figure-eight dodecaphyrin was done at the B3LYP/6-31G* level of DFT. Octaphyrins and dodecaphyrins bind trifluoroacetate anion effectively in their diprotonated forms, the binding constants (K) being 638 M,1 for dodecaphyrin 28, and 415 M,1 for octaphyrin 30. Electrochemical data reveal HOMO destabilization with increasing , electron conjugation, consistently with the large red shifts of the absorption bands. Preliminary studies on the use of these expanded porphyrins as third-order NLO materials were followed by measurements of their two-photon absorption (TPA) cross-sections [,(2)]. The ,(2) values increase upon going from the 26, rubyrins to the 54, dodecaphyrins, confirming our earlier observation that increases in ,-conjugated electrons increase the TPA values.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Effect of acetic acid and pH on the cofermentation of glucose and xylose to ethanol by a genetically engineered strain of Saccharomyces cerevisiaeFEMS YEAST RESEARCH, Issue 4 2010Elizabeth Casey Abstract A current challenge of the cellulosic ethanol industry is the effect of inhibitors present in biomass hydrolysates. Acetic acid is an example of one such inhibitor that is released during the pretreatment of hemicellulose. This study examined the effect of acetic acid on the cofermentation of glucose and xylose under controlled pH conditions by Saccharomyces cerevisiae 424A(LNH-ST), a genetically engineered industrial yeast strain. Acetic acid concentrations of 7.5 and 15 g L,1, representing the range of concentrations expected in actual biomass hydrolysates, were tested under controlled pH conditions of 5, 5.5, and 6. The presence of acetic acid in the fermentation media led to a significant decrease in the observed maximum cell biomass concentration. Glucose- and xylose-specific consumption rates decreased as the acetic acid concentration increased, with the inhibitory effect being more severe for xylose consumption. The ethanol production rates also decreased when acetic acid was present, but ethanol metabolic yields increased under the same conditions. The results also revealed that the inhibitory effect of acetic acid could be reduced by increasing media pH, thus confirming that the undissociated form of acetic acid is the inhibitory form of the molecule. [source] Nanoporous Copper with Tunable Nanoporosity for SERS ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 8 2009Lu-Yang Chen Abstract Nanostructured materials with designable microstructure and controllable physical and chemical properties are highly desired for practical applications in nanotechnology. In this article, it is reported that nanoporous copper with a tunable nanopore size can be fabricated by controlling the dealloying process. The influence of acid concentration and etching potential on the formation of nanoprosity is systematically investigated. With optimal etching conditions, the nanopore sizes can be tailored from ,15 to ,120,nm by controlling the dealloying time. It is found that the tunable nanoporosity leads to significant improvements in surface-enhanced Raman scattering (SERS) of nanoporous copper and peak values of SERS enhancements for both rhodamine 6G and crystal violet 10B molecules are observed at a pore size of ,30,50,nm. This study underscores the effect of complex three-dimensional nanostructures on physical and chemical properties and is helpful in developing inexpensive SERS substrates for sensitive instrumentations in molecular diagnostics. [source] Silage quality when Moringa oleifera is ensiled in mixtures with Elephant grass, sugar cane and molassesGRASS & FORAGE SCIENCE, Issue 4 2009B. Mendieta-Araica Abstract Fourteen different silages were prepared using mixtures of Moringa (Moringa oleifera), Elephant grass (Pennisetum purpureum cv Taiwan) or sugar cane (Saccharum officinarum). Molasses from sugar cane was used in the amounts of either 10 or 50 g kg,1 fresh matter (FM) in treatments without sugar cane. A completely randomized design with three replicates of each treatment was used. The silages were prepared in 1800 mL micro silos and opened after 120 d. The presence of Moringa and Elephant grass in the silage changed the pH by ,0·8 and +0·7, respectively (P < 0·001), indicating a favourable effect of Moringa on silage pH. Overall differences were found among treatments for dry matter content, crude protein and acetic acid concentrations, weight loss, CO2 production and silage pH after spoilage (P < 0·001). Weight loss was proportionately 0·034 and 0·014 in silages with and without sugar cane respectively (P < 0·001). Overall, differences (P < 0·05) were also found for neutral-detergent fibre and lactic acid concentrations, lactic acid bacteria counts, clostridial counts and time to spoilage of the silages. Treatments containing Moringa had higher lactic acid concentrations (+16 g kg,1 DM; P < 0·01) compared to treatments without but the presence of Moringa decreased time to spoilage by 67 h (P < 0·05). No differences were found in propionic acid concentration or fungal growth of the silages. It is concluded that Moringa can be used as a component of high quality silages which also contain high concentrations of crude protein. [source] The effect of harvest date and inoculation on the yield, fermentation characteristics and feeding value of forage pea and field bean silagesGRASS & FORAGE SCIENCE, Issue 3 2001M. D. Fraser Two experiments describe the ensiling potential of whole-crop forage peas (Pisum sativum) and field beans (Vicia faba). In Experiment 1, forage peas (cv. Magnus) and field beans (cv. Mayo) were harvested at 10, 12 and 14 weeks after sowing, and ensiled in 10 kg mini-silos either untreated or treated with an inoculant (Lactobacillus plantarum). In terms of yield and ensiling potential, the optimum growth stage for harvesting forage peas occurred at 12 weeks of growth. In contrast, delaying the harvest of field beans until 14 weeks gave the highest yields of dry matter (DM) and crude protein (CP). Changes in crop maturity had little effect on the chemical composition of the fresh forages, but between-harvest date differences were observed in the DM, ammonia-N, CP, water-soluble carbohydrates (WSC), acid-detergent fibre (ADF), neutral-detergent fibre (NDF), lactic acid and volatile fatty acids (VFA) concentrations and pH of the corresponding silages. Fermentation was improved by applying an inoculant. In Experiment 2, forage peas and field beans were harvested at 14 weeks after sowing and ensiled as round-bale silage, either untreated or treated with an inoculant. The yields of the crops were similar, and the only difference in the chemical composition of the wilted forages was a higher CP concentration in the field beans. However, after the ensiling process was complete, the forage pea silages were found to have significantly higher DM, WSC, starch and butyric acid concentrations compared with the field bean silages, and lower ammonia-N, CP, ADF, acetic acid and lactic acid concentrations. Inoculation was found to increase the lactic acid concentration and reduce the pH and ammonia-N and acetic acid concentrations of the silages. Each of the silages produced in Experiment 2 was offered to six Suffolk crossbred wether lambs, aged 10 months. Voluntary DM intakes were similar on all treatments, despite the apparent digestibility of the forage pea silages being significantly higher than that of the field bean silages. Nitrogen retention was higher for lambs offered forage pea silage. Application of an inoculant was found to have a negative effect on the amount of N retained, indicating the necessity for more detailed investigations into proteolytic activity within these crops during the fermentation process. [source] THE ROLE OF BACTERIAL SYMBIONTS IN AMINO ACID COMPOSITION OF BLACK BEAN APHIDSINSECT SCIENCE, Issue 3 2003Xue-xia Miao Abstract To evaluate the role of bacterial symbionts (Buchnera spp.) in the black bean aphids (Aphis craccivora Koch), the aphids were treated with the antibiotic, rifampicin, to eliminate their intracellular symbiotic bacteria. Analysis of protein and amino acid concentration in 7-day-old of aposymbiotic aphids showed that the total protein content per mg fresh weight was significantly reduced by 29%, but free amino acid titers were increased by 17%. The ratio of the essential amino acids was in general only around 20% essential amino acids in phloem sap of broad bean, whereas it was 44% and 37% in symbiotic and aposymbiotic aphids, respectively, suggesting that the composition of the free amino acids was unbalanced. For example, the essential amino acid, threonine represented 21.6% of essential amino acids in symbiotic aphids, but it was only 16.7% in aposymbiotic aphids. Likewise, two nonessential amino acids, tyrosine and serine, represented 8.9% and 5.6% of total amino acids in symbiontic aphids, respectively, but they enhanced to 21.1% and 13.6% in aposymbiotic aphids. It seems likely that the elevated free amino acid concentration in aposymbiotic aphids was caused by the limited protein anabolism as the result of the unbalanced amino acid composition. [source] Kinetics and mechanism of the dehydration reaction of sarcosine to a bislactame through diacyclperoxide intermediate in strong acidic mediumINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2009Homayoon Bahrami The influence of substitution on the amine functional group of glycine in the permanganic oxidation of such an ,-amino acid in moderately concentrated sulfuric acid medium has been investigated. Reaction products analysis has revealed that contrary to the usual ,-amino acid oxidation product, which is an aldehyde species, a valuable compound, namely 1,4-dimethylpiperazine-2,5-dione, has been obtained as the main product via a cheap, simple, efficient, and novel method. Sarcosine has been chosen as a substituted derivative of glycine, and the kinetics and mechanism of its permanganic oxidation have been investigated using a spectrophotometric technique. Conclusive evidence has proven delayed autocatalytic activity for Mn(II) in this reaction, analogous to some ,-amino acids. It has been revealed that such activity can show up when a certain concentration ratio of Mn(II) to sarcosine is built up in the medium, which we call the "critical ratio." The magnitude of the latter ratio depends on the sulfuric acid concentration. Considering the "delayed autocatalytic behavior" of Mn(II) ions, rate equations satisfying observations for both catalytic and noncatalytic routes have been presented. The reaction shows first-order dependence on permanganate ions and sarcosine concentrations in both catalytic and noncatalytic pathways, and apparent first-order dependence on Mn2+ ions in catalytic pathways. The correspondence of pseudo-order rate constants of the catalytic and noncatalytic pathways to Arrhenius and Eyring laws has verified "critical ratio" as well as "delayed autocatalytic behavior" concepts. The activation parameters associated with both pathways have been computed and discussed. Mechanisms for both catalytic and noncatalytic routes involving radical intermediates as well as a product having a diketopiperazine skeleton have been reported for the first time. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 689,703, 2009 [source] Evaporation of a model skin lotion with beta-hydroxy acidsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2004A. Al Bawab Synopsis Two , -hydroxy acids, malic and salicylic acids were combined with a non-ionic surfactant, a commercial pentaoxyethylene sorbitan mono-oleate and water to form a simple model of a skin lotion and the phase diagrams were determined. One emulsion formulation with relative amounts of the three components similar to those in commercial lotions was used to observe microscopically the changes in the emulsion structure during evaporation. The microscope images were subsequently compared to the information from the phase diagram under equilibrium conditions. The results showed the behavior of the systems of the two acids to be distinctly different; as exemplified by that of a typical formulation with 3% by weight of acid and 5% of surfactant. The malic acid system consisted of vesicles, exclusively formed by the surfactant and water, in an aqueous molecular solution of the acid and the initial evaporation resulted in an increase of the acid concentration in the aqueous solution to reach 35.5%, before solid crystals of the acid solid solution appeared. The salicylic acid formulation, on the other hand, already at the beginning of the determination consisted of water, particles of the acid solid solution and surfactant vesicles. In both cases the remaining deposit after total evaporation was particles of a solid acid solution and liquid surfactant. Résumé Deux acides , -hydroxy malique et salicylique ont été combinés avec un surfactant non ionique, un pentaoxyethylene sorbitan mono-oleate commercial et de l'eau pour former un model simple de lotion pour la peau. Leurs diagrammes de phase ont été déterminés. Une formule d'émulsion avec une quantité relative des trois composantes similaire a celles des lotions commerciales a été utilisée pour observer les changements microscopiques dans la structure de l'émulsion au cours de l,évaporation. Les images du microscope ont été ensuite comparées aux informations des diagrammes de phase dans les conditions d'équilibre. Les résultats ont montré que le comportement des systémes des deux acides est clairement différent, comme le montre l'exemple d'une formulation typique à 3% du poids d'acide et 5% du surfactant. Le système d'acide malique est constitué de vésicules exclusivement formées du surfactant et d'eau, dans une solution aqueuse moléculaire de l'acide, et l'évaporation initiale a eu comme consèquence l'augmentation de la concentration de l'acide en solution aqueuse qui a atteint 35.5% avant l'apparition des cristaux de la solution de l'acide solide. D'autre part la formulation de l'acide salicylique des le début de la détermination fut constituée d'eau, de particules de solution de l'acide solide et des vésicules du surfactant. Dans les deux cas les restes déposés après l'évaporation totale ètaient constitués des particules de la solution solide d'acide et du liquide surfactant. [source] Characteristics of traditional Croatian ewe's cheese from the island of KrkINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2008N MIKULEC Krk cheese is a hard, full-fat cheese made from raw sheep's milk, characterized by a delicate, full and strong flavour. The aim of this study was to determine farm influence on the chemical composition of sheep's milk for Krk cheese production, and the chemical characteristics of Krk cheese during ripening. Gross composition of the milk used complies with the average sheep's milk composition from the Croatian Adriatic region. During ripening, fat, protein, salt content and lactic acid concentration increased (P < 0.01), as well as the water-soluble nitrogen fraction and the 12%-trichloroacetic-acid-soluble nitrogen fraction (P < 0.05). Degradation of ,-casein could be an indicator of the ripening quality of Krk cheese. [source] Bio-hydrogen production from acetic acid steam-exploded corn straws by simultaneous saccharification and fermentation with Ethanoligenens harbinense B49INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 5 2010Ji-Fei Xu Abstract Bio-hydrogen produced from acetic acid steam-exploded corn straw (ASCS) by simultaneous saccharification and fermentation (SSF) with Ethanoligenes harbinense 49. The effects of acetic acid concentration and enzyme loading were investigated with respect to the maximum specific hydrogen production rate and hydrogen productivity. The hydrogen yield increased with increasing of acetic acid concentration, increased and then decreased with increasing of enzyme loading. The effect of enzyme loading for hydrogen production was more crucial than that of the acetic acid concentration. At acetic acid concentration of 16% and enzyme loading of 120 and 180,U/g, the maximum hydrogen yield and maximum specific hydrogen production rate was 72,ml/g ASCS and 103,ml/g VSS·d, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source] Experimental study on sulfur trioxide decomposition in a volumetric solar receiver,reactorINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2009Adam Noglik Abstract Process conditions for the direct solar decomposition of sulfur trioxide have been investigated and optimized by using a receiver,reactor in a solar furnace. This decomposition reaction is a key step to couple concentrated solar radiation or solar high-temperature heat into promising sulfur-based thermochemical cycles for solar production of hydrogen from water. After proof-of-principle a modified design of the reactor was applied. A separated chamber for the evaporation of the sulfuric acid, which is the precursor of sulfur trioxide in the mentioned thermochemical cycles, a higher mass flow of reactants, an independent control and optimization of the decomposition reactor were possible. Higher mass flows of the reactants improve the reactor efficiency because energy losses are almost independent of the mass flow due to the predominant contribution of re-radiation losses. The influence of absorber temperature, mass flow, reactant initial concentration, acid concentration, and residence time on sulfur trioxide conversion and reactor efficiency has been investigated systematically. The experimental investigation was accompanied by energy balancing of the reactor for typical operational points. The absorber temperature turned out to be the most important parameter with respect to both conversion and efficiency. When the reactor was applied for solar sulfur trioxide decomposition only, reactor efficiencies of up to 40% were achieved at average absorber temperature well below 1000°C. High conversions almost up to the maximum achievable conversion determined by thermodynamic equilibrium were achieved. As the re-radiation of the absorber is the main contribution to energy losses of the reactor, a cavity design is predicted to be the preferable way to further raise the efficiency. Copyright © 2009 John Wiley & Sons, Ltd. [source] Synthesis and characterization of polyacrylamides containing meso -2,3-dimercaptosuccinic acid end groupsADVANCES IN POLYMER TECHNOLOGY, Issue 1 2010Cemal Özero Abstract By using meso -2,3-dimercaptosuccinic acid-cerium(IV) sulfate and meso -2,3-dimercaptosuccinic acid-potassium permanganate redox systems, the polymerization reaction of acrylamide (AAm) monomer was examined in aqueous acidic medium at low temperatures. Water-soluble polyacrylamides bearing meso -2,3-dimercaptosuccinic acid end groups were synthesized using meso -2,3-dimercaptosuccinic acid as a reducing agent. The effects of parameters such as the molar ratio of acrylamide to initiator, temperature, polymerization time, and sulfuric acid concentration on the yields and molecular weights of polymers were investigated. The augmentation in initiator concentration resulted in a decrease in molecular weight but an increase in the yield of polymers. The increase in reaction temperature from 20 to 60°C led to a decrease in the yield from 56.80% to 20.58%. Ce(IV) and Mn(VII) ions are reduced to Ce(III) and Mn(II) ions in the polymerization reaction and the synthesized acrylamide polymers containing meso -2,3-dimercaptosuccinic acid end groups can absorb these ions at the end of the polymerization reaction. Ultraviolet-visible and atomic absorption measurements of polymer solutions were performed to indicate complexation between polyacrylamide and Ce(III) ions or Mn(II) ions. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:45,53, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20180 [source] Effects of adding liquid dl -methionine hydroxy analogue-free acid to drinking water on growth performance and small intestinal morphology of nursery pigsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2010C. Kaewtapee Summary This study was conducted to evaluate the effect of adding liquid dl -methionine hydroxy analogue free acid (LMA) to drinking water on growth performance, small intestinal morphology and volatile fatty acids in the caecum of nursery pigs. Twenty-four crossbred pigs (Large White × Landrace, BW ,18 kg) were divided into three groups with four replications of two piglets each. The piglets received drinking water without (control), with 0.05 or 0.10% LMA. The results indicated that adding LMA at 0.10% to drinking water significantly increased their weight gain, average daily feed intake (p < 0.05) and tended to improve the feed conversion ratio. Adding LMA to drinking water significantly increased their water intake and significantly reduced the pH of drinking water (p < 0.01), thus total plate count (p < 0.01) and Escherichia coli in drinking water was reduced (p < 0.05), while the total number of bacteria in the caecum was not significantly affected. Liquid dl -methionine hydroxy analogue free acid supplementation in drinking water tended to decrease pH in the stomach, duodenum, jejunum, colon and rectum. Furthermore, adding LMA at 0.10% significantly increased villous height in the duodenum, jejunum and ileum (p < 0.05), and the villous height:crypt depth ratio in the jejunum and ileum (p < 0.01) was higher, whereas acetic acid concentration in the caecum was significantly lower than in the control group. It could be concluded that adding LMA to drinking water improved growth performance of the nursery pigs because of high water quality and high nutrient utilization caused by an improvement of small intestinal morphology (not from nutritional effect of methionine source). [source] Effect of different liquid cultures of live yeast strains on performance, ruminal fermentation and microbial protein synthesis in lambsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 6 2008M. K. Tripathi Summary Three yeast strains, Kluyveromyces marximanus NRRL-3234 (KM), Saccharomyces cerevisiae NCDC-42 (SC) and Saccharomyces uvarum ATCC-9080 (SU), and a mixed culture (1:1:1 ratio) were evaluated for their value as probiotics in lamb feeding in two experiment. In experiment I and II, 20 and 30 pre-weaner lambs were fed for 63 and 60 days in two and three equal groups respectively. All lambs were offered ad libitum a creep mixture and Zizyphus nummularia leaves, and yeasts were dosed orally. In experiment I, one group received no yeast, the other of the mixed culture (1.5,2 × 1010 live cells/ml). In experiment II, yeast cultivation was modified yielding 1.5,2 × 1013 live cells/ml. Lambs of the three experimental groups received 1 ml/kg live weight of one of the individual yeasts. Feed intake did not differ among groups of both experiments with the exception of SC-supplemented lambs in experiment II which showed a trend to higher intakes per kg metabolic body weight and in percentage of body weight when compared with KM- and SU-supplemented lambs. Supplementation of the mixed yeast culture had no effect on intakes of digestible crude protein and metabolisable energy, nutrient digestibility, nitrogen balance and rumen fermentation characteristics (pH, ammonia, volatile fatty acid concentration, protozoa count) and urinary allantoin as an indicator of microbial protein synthesis. The same was true for comparisons in experiment II except ciliate protozoa counts, which showed a trend to be the highest with SU and the lowest with SC. The results of present study show that the response of lambs to supplemented live yeast cultures is inconsistent, as it lacked to have an effect in the present study, and that differences among strains were small, even when supplemented at a much higher live cell count. [source] Effect of dietary linoleic acid concentration and vitamin E supplementation on cell desquamation and susceptibility to oxidative damage of pig jejunal mucosaJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1-2 2001C. J. López Bote Sixty Large White × Great York pigs weighing approximately 60 kg were individually fed on six experimental diets. The experiment was organized in a 3 × 2 factorial arrangement design with three different fat sources and a basal or supplemented (200 mg/kg diet) level of ,-tocopheryl acetate. All diets contained the same concentration of saturated fatty acids (15 ± 0.2 g/kg dry matter) but differed in the concentration of C18 : 2 (14 ± 0.5, 18 ± 0.4 and 21 ± 0.6 g/kg) and monounsaturated fatty acids (19 ± 0.2, 15 ± 1.2 and 10 ± 1.3 g/kg). No effect of dietary treatment was observed on weight gain and feed consumption. A histological study of the jejunal mucosa showed lower cell desquamation in groups containing a supplemental level of ,-tocopheryl acetate (p=0.080). A higher cell desquamation was found in the groups fed diets containing the higher concentration of C18 : 2 (p=0.087). We also observed an interaction effect (p < 0.001) of dietary fat source and vitamin E supplementation on jejunal cell desquamation in which the effect of dietary vitamin E was lower when diets with a low concentration of C18 : 2 were administered. In vitro- induced oxidation of jejunal mucosa homogenates was lower in pigs fed diets supplemented with ,-tocopheryl acetate (p < 0.002). The dietary concentration of C18 : 2 significantly affected oxidation of pig jejunal mucosa (p < 0.002). [source] Changes in amino acid composition in the tissues of African catfish (Clarias gariepinus) as a consequence of dietary L-carnitine supplementsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2002R. O. A. Ozório A study was undertaken to examine the effect of different amounts of dietary lysine (13 and 21 g kg,1 diet), lipid (80 and 160 g kg,1 diet) and L -carnitine (0.2 and 1.0 g kg,1 diet) on growth performance, proximate composition and amino acid metabolism of the African catfish (Clarias gariepinus). Juvenile African catfish (23 ± 1.5 g/fish) were stocked into 70-L aquaria (16 aquaria, 28 fish/aquarium) connected to a recirculation system during a maximum period of 74 days. All groups were fed at a level of 24 g kg,0.8 day,1 in an experiment run at pair feeding. Animals receiving 1.0 g carnitine accumulated up to six times more carnitine in their tissues than animals receiving 0.2 g (P < 0.05). Acyl-carnitine and free L -carnitine levels increased in the whole body and in tissues. Dietary L -carnitine supplements increased protein-to-fat ratios in the body, but did not affect growth rate. Protein-to-fat ratios were only affected when the biosynthesis capacity of L -carnitine was restricted due to low lysine levels and when there was a shortage of dietary fat. When lysine was offered at 21 g kg,1 feed, dietary L -carnitine supplements did not affect the amino acid concentrations of body tissues. Dietary L -carnitine supplements raised the concentration of glutamic acid,>,aspartic acid,>,glycine > alanine > arginine > serine > threonine in skeletal muscle tissue (P < 0.05). Total amino acid concentration in muscle and liver tissues (dry-matter basis) increased from 506 to 564 and from 138 to 166 mg g,1, respectively, when diets were offered with high L -carnitine, low lysine and low fat levels. These data suggest that dietary L -carnitine supplementation may increase fatty acid oxidation and possibly decrease amino acid combustion for energy. [source] | ||||||||||||||||||||||||||||||||||||||||