The synthesis, NMR properties and preliminary polarization tests on protonated and perdeuterated forms of α-trimethylglutamine (NMe3 Gln), α-trimethylglutamate (NMe3 Glu) and ε-trimethyllysine (NMe3 Lys) are reported. The (15) N-permethylated, perdeuterated amino acids display very long (15) N-T1 values, ranging between 190 and 330 s, are well polarized by the dynamic ...

In this work, a facile electrochemical sensor based on poly(diallyldimethylammonium chloride) (PDDA) functionalized graphene (PDDA-G) and graphite was fabricated. The composite electrode exhibited excellent selectivity and sensitivity towards uric acid (UA), owing to the electrocatalytic effect of graphene nanosheets and the electrostatic attractions between PDDA-G and UA. The anodic peak ...

A biocompatible electrochemical sensor for selective detection of epinephrine (EP) in the presence of 1000-fold excess of ascorbic acid (AA) and uric acid (UA) was fabricated by modifying the carbon paste electrode (CPE) with multi-walled carbon nanotubes (MWCNTs) using a casting method. The electro-catalytic activity of the modified electrode for ...

The kinetic nature of the phosphoric acid digestion reaction enables clumped isotope analysis of carbonates using gas source isotope ratio mass spectrometry (IRMS). In most laboratories acid digestions are performed at 25°C in sealed vessels or at 90°C in a common acid bath. Here we show that different Δ47 results ...

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 ...

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 ...

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 ...

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.

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 ...

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.

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 ...

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 ...

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. ...

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 ...

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 ...

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 ...

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 ...

During L-glutamate production, phosphoenolpyruvate carboxylase and pyruvate carboxylase (PCx) play important roles in supplying oxaloacetate to the tricarboxylic acid cycle. To explore the significance of PCx for L-glutamate overproduction, the pyc gene encoding PCx was amplified in Corynebacterium glutamicum GDK-9 triggered by biotin limitation and CN1021 triggered by a temperature ...

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 ...

Boric acid-based fluorescent complex probe of BBV-HPTS (boronic acid-based benzyl viologen (BBV) and hydroxypyrene trisulfonic acid trisodium salt (HPTS)) was rarely used for sensitive sensing of saccharide (especially glycoprotein) via electrophoresis. We proposed a novel model of moving supramolecule boundary (MSB) formed with monosaccharide or glycoprotein in microcolumn and the ...

OBJECTIVE: To determine the in vivo ability to predict uric acid stone composition by Hounsfield units (HU) with the addition of urine parameters. METHODS: We reviewed all consecutive stones sent for analysis during a 4-year period from our institution for patients with an in-house computed tomography (CT) scan within the prior ...

To improve short-chain fatty acids (SCFAs) production from waste activated sludge (WAS), studies that focus on pre-treatment methods, pH control or adding extra carbon like rice were reported. In this study, a kind of green waste (perennial ryegrass) was used as carbon source to adjust carbon to nitrogen ratio (C/N) ...

In this work, the subsite -3 of cyclodextrin glycosyltransferase (CGTase) from Paenibacillus maceras was engineered to improve maltodextrin specificity for 2-O-d-glucopyranosyl-l-ascorbic acid (AA-2G) synthesis. Specifically, the site-saturation mutagenesis of tyrosine 89, asparagine 94, aspartic acid 196, and aspartic acid 372 in subsite -3 was separately performed, and three mutants Y89F ...

The present work describes a new solution-free strategy for preparation of cluster-like nano/micro CuO/ZnO particles in dielectric barrier discharge (DBD) in which the brass acts as the inner electrode. The cataluminescence (CTL) behaviour of such prepared material for acetic acid was studied for analytical application. Under the optimized conditions, the ...

Present formic acid fuel cell efficiency is limited by low kinetics at the anode, indicating the need for effective catalysts to improve the formic acid oxidation. As a prerequisite, the nature of adsorbed species and specifically the reaction intermediates formed in this process needs to be examined. This work focuses ...

We identified the critical amino acid residues for substrate recognition using two firefly luciferases from Pylocoeria miyako (PmL) and Hotaria parvura (HpL), as these two luciferase enzymes exhibit different activities toward ketoprofen. Specifically, PmL can catalyze the apparent enantioselective thioesterification reaction, while HpL cannot. By comparing the amino acid sequences ...

De gustibus: β-homoDNA has the singular property of being able to pair with homochiral complements of opposite chirality, with a greater stability than that observed in the corresponding isochiral complexes. Relevant to etiological investigations on nucleic acid structure, these results suggest the existence of a relationship between carbohydrate structure and ...

Enterobacter asburiae PSI3 is known to efficiently solubilize rock phosphate by secretion of approximately 50 mM gluconic acid in Tris-buffered medium in the presence of 75 mM glucose and in a mixture of seven aldosugars each at 15 mM concentration, mimicking alkaline vertisol soils. Efficacy of this bacterium in the rhizosphere requires P release ...

In exploring the capability of nuclear magnetic resonance (NMR) spectroscopy for pomegranate juice analysis, the eight aromatic singlet resonances of α- and β-punicalagin were clearly identified in the (1)H NMR spectra of juice samples. The four downfield resonances were found to be sensitive to small pH changes around pH 3.50 where ...

The lipophilic amino acid, (S)-2-aminoundecanoic acid, was synthesized and incorporated at a number of specific positions within the peptide sequence of anoplin. These lipophilic anoplin analogs showed to be more active against Escherichia coli and Staphylococcus aureus compared to native anoplin, while the EC50-value of hemolysis was at least one ...

A Zn(ii) complex was found to exhibit greatly enhanced fluorescence in the presence of histidine but not in the presence of any other amino acids including cysteine. This sensor could also distinguish histidine from other imidazole derivatives.

Tigernut starch has been isolated and modified by forced retrogradation of the acidic gel by freezing and thawing processes. Relevant physicochemical and functional properties of the new excipient (tigernut starch modified by acid gelation and accelerated (forced) retrogradation (STAM)) were evaluated as a direct compression excipient in relation to the ...

Several important neurotransmitter precursors were hyperpolarized via homogeneous hydrogenation with parahydrogen. Polarization enhancement was achieved for (1)H and (13)C spins by several orders of magnitude compared to thermal spectra. Such large signal enhancements of these molecules could facilitate neurotransmitter studies.

Acetylated corn starch (ACS) was synthesized by the reaction of native corn starch (NCS) with acetic anhydride (AA) and acetic acid in an aqueous medium in the presence of p-toluenesulfonic acid (PTSA) as a catalyst. The factors that could affect the degree of substitution (DS) of corn starch were investigated ...

The present work describes the characterization and thermal properties of hydrophobic starch obtained by the esterification of cassava starch with acyl imidazoles, acid chlorides and methyl ester derivatives of fatty acids with n-alkyl chains with 12 to 22 carbon atoms, in order to compare the dependence of their properties as ...

Utilizing the colorimetric and fluorogenic changes, a system based on polydiacetylenes (PDAs) is developed for the detection of neomycin. The PDA supramolecules polymerized from the mixed liposome composed of N-(3-hydroxyphenyl)pentacosa-10,12-diynamide (PCDA-AP) and pentacosa-10,12-diynoic acid (PCDA) at an optimized ratio of 1:9 display a unique colorimetric change (blue to red) and ...

To investigate the involvement of two melanin-concentrating hormones (MCHs) in skin color change and appetite in flatfish, we isolated two forms of prepro-melanin concentrating hormone (pMCHs) mRNA in the starry flounder Platichthys stellatus and compared their amino acid structures to those of other animals. Then, we examined the relationship of ...

The ability of triazolium salts to serve as a precatalyst for both an acid and a powerful base/nucleophile (controlled by additives) has been exploited in a process characterised by a unique in situ catalyst modification strategy.

Human consumption of flaxseed is increasing due to its health benefit properties and extrusion processes can enhance its nutritional quality. Extruded flaxseed meal (EFM) obtained in a pilot plant was characterized and incorporated in flour mixes and cereal-based bars to demonstrate its nutritious usefulness. Amino acid content was not affected ...

Chromite ore processing residue (COPR), the solid waste product from the high-temperature alkaline processing of ferrochromite (FeO·CrO), contains Cr(VI) in soluble and insoluble compounds formed in the roasting process. This research investigated tartaric acid in combination with Mn and isopropyl alcohol (IPOH ) as co-reductants for reagent- and COPR-derived Cr(VI). ...

BACKGROUND: Phytic acid of soy meal (SM) could influence protein and important minerals digestion of monogastric animals. Aspergillus oryzae (ATCC 9362) solid state fermentation was applied to degrade phytic acid in SM. Two - stage temperature fermentation protocol was investigated to increase the degradation rate. The first stage was to ...

Twenty years ago two different polymorphs of carbonic acid, α- and β-H2CO3, were isolated as thin, crystalline films. They were characterized by infrared and, lately, by Raman spectroscopy. Determination of the crystal structure of these two polymorphs, using cryo-powder and thin film X-ray diffraction techniques, has failed so far. Recently, ...

Folin-Ciocalteau method of total phenolics assay, originally developed for protein determination, has recently evolved as a total antioxidant capacity assay, but found to be incapable of measuring lipophilic antioxidants due to the high affinity of FC chromophore, i.e. multivalent-charged phospho-tungsto-molybdate(V), toward water. Thus, the FC method was modified and standardized ...

We tested the stability and reaction of several amino acids using hydrothermal system simulators: an autoclave and two kinds of flow reactors at 200-250 °C. This study generally showed that there is a variation in the individual amino acids survivability in the simulators. This is mainly attributed to the following factors; ...

We report loading of vitamin C (ascorbic acid) on to lysozyme-shelled microbubbles. The interaction between lysozyme-shelled microbubbles and vitamin C was studied by use of cyclic and differential pulse voltammetry, zeta potential measurements, and scanning electron microscopy. The effect of microbubbles on electrochemical measurement of ascorbic acid was evaluated. The ...

Chlorogenic acid and caffeic acid were selected as test samples for separation by the pH-zone-refining counter-current chromatography. The separation of these test samples was performed with two-phase solvent system composed of methyl-tert.-butyl-ether-acetonitrile-water at a volume ration of 4:1:5 (v/v) where trifluoroacetic acid (8 mM) was added to the organic stationary ...

Time-resolved utilization of multiple amino acids by Phaeobacter inhibens DSM 17395 was studied during growth with casamino acids. The 15 detected amino acids could be grouped according to depletion rate into four different categories, i.e. from rapid (category I) to non-depletion (category IV). Upon entry into stationary growth phase, amino ...

The influences of Tween 80 on the pullulan production, cell growth, glucosyltransferase activity and fatty acid composition of the cells were studied. The addition of Tween 80 to the culture medium significantly enhanced the pullulan production, but had no impact to biomass accumulation. Glucosyltransferase activity involved in pullulan synthesis was ...

Hepatopancreatic brush border membrane vesicles (BBMV), made from Atlantic White shrimp (Litopenaeus setiferus), were used to characterize the transport properties of (3)H-L-leucine influx by these membrane systems and how other essential amino acids and the cations, sodium and potassium, interact with this transport system. (3)H-L-leucine uptake by BBMV was pH-sensitive ...

Our dependency on reduced carbon for energy has led to a rapid increase in the search for sustainable alternatives and a call to focus on energy densification and increasing biomass yields. In this study we generated a uniquely stabilised plant structural protein (cysteine-oleosin) that encapsulates triacylglycerol (TAG). When co-expressed with ...