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Results 401 - 450 of 2882
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Wang Xin - - 2013
Activated carbon (AC) is a high performing and cost effective catalyst for oxygen reduction reactions (ORRs) of air-cathodes in microbial fuel cells (MFCs). Acidic (HNO3) and alkaline (KOH) pretreatments on AC at low temperature (85°C) are conducted to enhance the performance of MFCs. The alkaline pretreatment increased the power density ...
Suneesh P V - - 2013
Tantalum oxide honeycomb nanostructures (THNS) were fabricated by electrochemical anodisation of tantalum in H2SO4-HF medium. XRD analysis showed that annealing of THNS at 400°C improves the crystallinity. HRSEM and AFM results illustrated that nanopores with an average diameter of 30nm were uniformly distributed and the pore size reduced to 24nm ...
Goriparti Subrahmanyam - - 2013
Ellagic acid, a naturally occurring polyphenol, extracted from pomegranate husk, is found to be a very good organic electrode material for rechargeable lithium batteries with high reversible capacities of ∼450 and 200 mA h g(-1) at C/10 and C/2.5 discharge rates, respectively; ex situ NMR studies reveal possible lithiation-delithiation modes ...
Liu Rui-Lin - - 2013
Based on microwave-ultrasonic synergistic in situ extraction-derivatisation (MUED), gas chromatography-mass spectrometry was proposed for rapid analysis of fatty acid profiles in raw nut and seed materials. Several critical experimental parameters for MUED, including reaction temperature, microwave power, amounts of catalyst and derivatisation reagent, have been optimised using response surface methodology. ...
Wang Wen - - 2013
Acid and alkaline pretreatments for enhanced hydrogen production from cassava stillage were investigated in the present study. The result showed that acid pretreatment was suitable for enhancement of soluble carbohydrate while alkaline pretreatment stimulated more soluble total organic carbon production from cassava stillage. Acid pretreatment thereby has higher capacity to ...
Tsubaki Shuntaro - - 2013
Polyoxometalate (POM) clusters were utilized as recyclable acid catalysts and microwave-absorbing agents for the microwave-assisted hydrolysis of corn starch and crystalline cellulose. Phosphotungstic (PW) and silicotungstic (SiW) acids showed high hydrolyzing activity, while phosphomolybdic acid (PMo) showed lower glucose stability. The PW catalyst could be recycled by ether extraction at ...
Deo Kirti S - - 2013
Melasma is a relatively common, acquired symmetric hypermelanosis characterized by irregular light to gray-brown macules involving sun-exposed areas. Kojic acid, with its depigmenting potential due to tyrosinase inhibition and suppression of melanogenesis, has become a vital component of the dermatologists' armamentarium against melasma. To study and compare the efficacy of ...
Desriac N - - 2013
This study aims to quantify the effect of salt and acid preliminary exposure on acid resistance of vegetative cells of Bacillus weihenstephanensis. The psychrotolerant strain KBAB4 was cultured until the mid-exponentially phase (i) in BHI, (ii) in BHI supplemented with 2.5% salt or (iii) in BHI acidified at pH 5.5 ...
Sinha Sukumar - - 2013
A simple, sensitive method for the determination of meta-chlorobenzoic acid in bupropion hydrochloride is described. Chromatographic separation of m-chlorobenzoic acid is achieved using a mobile phase consisting of n-hexane and ethanol (1000:50, v/v) at a flow rate of 1.0 ml/min on a Chiralpak ADH (250 × 4.6 mm). Absorbance is ...
Miftodei Alina Monica AM Discipline of Inorganic Chemistry, University of Medicine and Pharmacy "Grigore T. Popa" - - 2013
Through univalent oxidation chlorpromazine forms a colored and relatively stable radical cation with maximum absorbance at 525 nm, considered a redox mediator in a number of b iochemical reactions. To develop a spectrometric method for the determination of total antioxidant activity based on the reaction of chlorpromazine radical capture by ...
Ali M Abbas MA Department of Chemistry, Rajshahi University of Engineering and Technology, - - 2013
Background. Microwave heating is one of the most attractive cooking methods for food preparation, com-monly employed in households and especially in restaurants for its high speed and convenience. The chemical constituents of oils that degrade during microwave heating do so at rates that vary with heating temperature and time in ...
Abid Muhammad - - 2013
A study was initiated with the objective of evaluating the effects of sonication treatment on quality characteristics of apple juice such as polyphenolic compounds (chlorogenic acid, caffeic acid, catechin, epicatechin and phloridzin), sugars (fructose, glucose and sucrose), mineral elements (Na, K, Ca, P, Mg, Cu and Zn), total carotenoids, total ...
Wang Qi - - 2013
A sensitive electrochemical active interface for sugar sensing based on the specific boronic acid-diol binding was established. The sensing matrix was formed by stirring a suspension of graphene oxide (GO) with 4-aminophenylboronic acid (APBA). The resulting composite consists of a water insoluble precipitate of reduced graphene oxide (rGO) with APBA ...
Chen Suming - - 2013
Carbon nanodots were applied for the first time as a new matrix for the analysis of low-molecular-weight compounds by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in both positive- and negative-ion modes. A wide range of small molecules including amino acids, peptides, fatty acids, as well as β-agonists and ...
Giuberti G - - 2013
The need to improve the knowledge of fermentation processes within the digestive tract in pigs is growing, particularly for ingredients that may act as potential prebiotic sources, such as resistant starch (RS). A study (based on enzymatic digestion followed by in vitro fermentation) was conducted to investigate whether various sources ...
Park Soo-Yun - - 2013
In the present study, carotenoids, anthocyanin and phenolic acids of cauliflowers (Brassica oleracea L. ssp. botrytis) with various colored florets (white, yellow, green and purple) were characterized to determine their phytochemical diversity. Additionally, 48 metabolites comprising amino acids, organic acids, sugars and sugar alcohols were identified using gas chromatography-time-of-flight mass ...
Freitas Maria Betânia de - - 2013
The nitroaromatic compound 4-bromomethyl-3-nitrobenzoic acid (ANB) is a promising antitumoral agent whose activity has recently been investigated. Forced degradation studies were conducted on ANB with a high-performance liquid chromatography-ultraviolet assay to establish its stability and selectivity. ANB was subjected to degradation studies under hydrolytic (acid and alkaline), oxidative and light ...
Madeira Pedro P - - 2013
Partition ratios of 8 free l-amino acids (Gln, Glu, His, Lys, Met, Ser, Thr, and Tyr) were measured in 10 different polymer/polymer aqueous two-phase systems containing 0.15 M NaCl in 0.01 M phosphate buffer, pH 7.4. The solute-specific coefficients representing the solute dipole/dipole, hydrogen-bonding and electrostatic interactions with the aqueous environment of ...
Liang Liya - - 2013
In this study, repetitive production of succinic acid from lignocellulose hydrolysates by enhancement of ATP supply in metabolically engineered E. coli is reported. Escherichia coli BA305, a pflB, ldhA, ppc, and ptsG deletion strain overexpressing ATP-forming phosphoenolpyruvate (PEP) carboxykinase (PEPCK), produced a final succinic acid concentration of 83gL(-1) with a ...
Braunberger Christina - - 2013
The herb of Drosera peltata, commonly named the shield sundew, is used as an antitussive in phytotherapy, although the plants' composition has not been determined in detail so far. Hence, in this study, we present a validated, sensitive, reliable, and cheap narrow-bore LC-DAD method for the simultaneous quantification of flavonoids ...
Kim Hyun-Wook - - 2013
This study was conducted to evaluate the antioxidant effects of soy sauce on lipid oxidation and color stability of raw beef patties. Raw beef patties were formulated with four solutions such as NaCl (sodium chloride solution), NaCl/SS (1:1 ratio of sodium chloride and soy sauce solution), SS (soy sauce solution), ...
Malaj Naim - - 2013
Anthocyanins are a natural source of pigments in plants and their processed food products have become attractive and excellent candidates to replace the synthetic colourants due to their characteristic intense colours and associated health benefits. The intermolecular copigmentation between anthocyanins and other colourless compounds has been reported to be an ...
Piergies Natalia - - 2013
This paper shows systematic spectroscopic studies using Fourier-transform infrared absorption (FT-IR), Fourier-transform Raman (FT-Raman), and surface enhanced Raman (SERS) in an aqueous silver sol of fluoro- and formyl- analogues of phenylboronic acids: 2-fluorophenylboronic acid (2-F-PhB(OH)2), 3-fluorophenylboronic acid (3-F-PhB(OH)2), 4-fluorophenylboronic acid (4-F-PhB(OH)2), 2-formylphenylboronic acid (2-CHO-PhB(OH)2), 3-formylphenylboronic acid (3-CHO-PhB(OH)2), and 4-formylphenylboronic acid ...
Hu Xianmei - - 2013
The potential use of arachidonic acid (AA) to enhance the production of β-carotene in Blakeslea trispora was investigated in this work. To study the mechanism of the B. trispora response to AA, we used a systematic analytical approach to investigate the changes in the B. trispora cell metabolome at different ...
Aadil Rana Muhammad - - 2013
Sonication is recognised as a potential technique for improvement in the quality of fruit juices. This study was initiated with the objective of evaluating the effect of sonication treatments on some important quality parameters of grapefruit juice such as physico-chemical (pH, acidity and °Brix), Hunter colour values (L(∗), a(∗) and ...
Lin Xiaoyun - - 2013
A novel modified electrode was constructed by the electro-polymerization of 4,5-dihydroxy-3-[(2-hydroxy-5-sulfophenyl)azo]-2,7-naphthalenedisulfonic acid trisodium salt (acid chrome blue K (ACBK)) at a graphene oxide (GO)-nafion modified glassy carbon electrode (GCE). The characterization of an electrochemically synthesized poly-ACBK/GO-nafion film was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), atomic force microscopy ...
Meng F - - 2013
In this study, a synchronous fluorescence detection method for ferulic acid (FA) is proposed based on a redox reaction between FA and Ce(IV) sulfate in dilute sulfuric acid medium at room temperature. It was found that FA could reduce Ce(IV) to Ce(III) in acidic medium, and sodium tripolyphosphate could further ...
Figueiredo-Filho Luiz C S - - 2013
We explore the recent reports that the use of graphene modified electrodes gives rise to the electrocatalytic oxidation of kojic acid. It is demonstrated that large quantifiable voltammetric signatures are observed on bare/unmodified graphitic electrodes, which are shown to be analytically useful and superior to those observed at graphene modified ...
Suzuki Yoko - - 2013
We identified two compounds that demonstrated 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity from cultures of Lactobacillus plantarum. Spectroscopic analyses proved these compounds to be L-3-(4-hydroxyphenyl) lactic acid (HPLA) and L-indole-3-lactic acid (ILA). The respective EC50 values for HPLA and ILA were 36.6 ± 4.3 mM and 13.4 ± 1.0 mM.
Winkler Henning - - 2013
Being completely bio-based, fatty acid starch esters (FASEs) are attractive materials that represent an alternative to crude oil-based plastics. In this study, two synthesis methods were compared in terms of their efficiency, toxicity and, especially, product solubility with starch laurate (C12) as model compound. Laurates (DS>2) were obtained through transesterification ...
Sakharov Ivan Yu - - 2013
Using a full factorial design the optimization of experimental conditions of enhanced chemiluminescence reaction (ECR) catalyzed by horseradish peroxidase (HRP) in the presence of 3-(10'-phenothiazinyl)propionic acid (PPA) as a primary enhancer was performed. The effect of concentrations of PPA, hydrogen peroxide, MORPH, luminol, and Tris on a ratio of peroxidase-catalyzed ...
Echavarría Ap - - 2013
The formation of soluble melanoidins from a single combination of sugar (fructose) and amino acid model systems were evaluated kinetically. The selected amino acids, commonly found in apple juice and highly reactive in the Maillard reaction, were asparagine, aspartic acid, and glutamic acid. The effect of these reagents and the ...
Hunter Rebecca A RA Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, - - 2013
Standard photolithographic techniques and a nitric oxide (NO) selective xerogel polymer were utilized to fabricate an amperometric NO microfluidic sensor with low background noise and the ability to analyze NO levels in small sample volumes (~250 μL). The sensor exhibited excellent analytical performance in phosphate buffered saline, including a NO ...
Peng Yue - - 2013
The SCR activities of MoO3-CeO2 catalysts are enhanced by both Lewis and Brønsted acidities provided by surface cerium atoms and amorphous MoO3 structures, respectively, but are suppressed by stable adsorbed nitrate or nitrite species on the defect sites of CeO2.
Prasad Bhim Bali - - 2013
A new molecularly imprinted polymer-matrix (titanium dioxide nanoparticle/multiwalled carbon nanotubes) nanocomposite was developed for the modification of pencil graphite electrode as an enantioselective sensing probe for aspartic acid isomers, prevalent at ultra trace level in aqueous and real samples. The nanocomposite having many shape complementary cavities was synthesized adopting surface ...
Mahfoudhi Nesrine - - 2013
The use of coatings is a technique used to increase postharvest life of the fruit. Almond gum exudate was used, in comparison with gum arabic, at concentrations of 10% as a novel edible coating, to preserve the quality parameters of tomato (Solanumlycopersicum). Fruits were harvested at the mature-green stage of ...
Li F F College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, - - 2013
This study was conducted to evaluate chemical composition, nitrogen-corrected true metabolizable energy (TMEn) and true amino acids digestibility of corn distillers dried grains with solubles (DDGS) produced in China. Twenty five sources of corn DDGS was collected from 8 provinces of China. A precision-fed rooster assay was used to determine ...
Miura Katsuyuki K Department of Health Science, Shiga University of Medical Science, Otsu, Japan. - - 2013
In short-term feeding trials, replacement of other macronutrients with monounsaturated fatty acid reduces blood pressure. However, observational studies have not clearly demonstrated a relationship between monounsaturated fatty acid intake and blood pressure. We report associations of monounsaturated fatty acid intake of individuals with blood pressure in a cross-sectional study. The ...
Jindal Kajal - - 2013
Nitrogen-doped zinc oxide thin films (ZnO:N) have been realized as a potential matrix for the development of a uric acid biosensor. The correlation between the change in property of the ZnO film with N doping concentration and its biosensing response has been studied. The nitrogen dopant in a ZnO film ...
Hwang Ko-Eun - - 2013
Raw and deep fried chicken nuggets containing various levels of ganghwayakssuk ethanolic extract (GE) in combination with ascorbic acid (Aa) were evaluated for shelf-life during refrigerated storage (4°C). The pH and color (lightness, redness, and yellowness) values of raw and deep fried samples were significantly affected by the addition of ...
Nadler André - - 2013
Caged compounds are designed to release biologically active signaling molecules with temporal, spatial, and even subcellular resolution. But how localized does the signal stay? Using the example of diacylglycerol, some signal responses (PKC) are shown to remain spatially distinct while other signals ([Ca(2+) ]i ) spread across the entire cell. ...
Zhou Miao - - 2013
A simple and novel supramolecular hydrogel was prepared from ferrocene (Fc) modified amino acid phenylalanine (F) and utilized as electrochemical immunosensing platform for the detection of human IgG. Scanning electron microscopy (SEM) characterization indicated that the hydrogel is composed of fibrils with diameter around 50-100nm and length extend to 1mm. ...
Lu Zexiang - - 2013
Acidic ionic liquids (AILs) as a novel catalyst in biomass liquefaction can accord with the demand of green chemistry and enhance the development of biomass thermal chemical conversion. A series of AILs containing HSO4- were synthesized by the imidazolium cation functionalization and applied to the Chinese fir sawdust liquefaction in ...
Li Chuanchang - - 2013
A novel mineral-based composite phase change materials (PCMs) was prepared via vacuum impregnation method assisted with microwave-acid treatment of the graphite (G) and bentonite (B) mixture. Graphite and microwave-acid treated bentonite mixture (GBm) had more loading capacity and higher crystallinity of stearic acid (SA) in the SA/GBm composite. The SA/GBm ...
Nasser Abdelhamid Hani - - 2013
The present study introduces two novel organic matrices for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the analysis of small molecules. The first matrix is "2-amino-4,5-diphenylfuran-3-carboxylic acid" (also called furoic acid, FA) which was synthesized and then characterized by ultraviolet (UV), infrared (FTIR), nuclear magnetic resonance NMR ((1)H and ...
Lu Yuanyuan Y State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, - - 2013
Chlorogenic acid and caffeic acid were selected as test samples for separation by the pH-zone-refining countercurrent chromatography (CCC). The separation of these test samples was performed with a two-phase solvent system composed of methyl-tert-butyl-ether/acetonitrile/water at a volume ratio of 4:1:5 v/v/v where trifluoroacetic acid (TFA; 8 mM) was added to ...
Tan Hooi Teng - - 2013
Oil palm empty fruit bunch (EFB) is abundantly available in Malaysia and it is a potential source of xylose for the production of high-value added products. This study aimed to optimize the hydrolysis of EFB using dilute sulfuric acid (H2SO4) and phosphoric acid (H3PO4) via response surface methodology for maximum ...
Jaramillo Oscar Johnny - - 2013
This study unifies contradictory conclusions reported in literature on acid hydrolysis of lignocellulosic materials, using batch and plug flow reactors, regarding the influence of the initial liquid ratio of acid aqueous solution to solid lignocellulosic material on sugar yield and concentration. The proposed model takes into account the volume change ...
Limón Piedad M - - 2013
The multiequilibrium system of reactions of cyanidin 3-glucoside at acidic and mildly acidic pH values was studied in the presence of caffeine as a copigment. The thermodynamic and kinetic constants were determined using the so-called direct and reverse pH jump experiments that were followed by conventional UV-vis spectroscopy or stopped ...
Long Bo - - 2013
The gas-phase reactions of sulfuric acid catalyzed hydrolysis of formaldehyde and formaldehyde with sulfuric acid and H2SO4…H2O complex are investigated employing the high-level quantum chemical calculations with M062X and CCSD(T) theoretical methods and the conventional transition state theory (CTST) with Eckart tunneling correction. The calculated results show that the energy ...
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