Acid-functionalized nanoparticles for biomass hydrolysis

Science.gov (United States)

Pena Duque, Leidy Eugenia

Cellulosic ethanol is a renewable source of energy. Lignocellulosic biomass is a complex material composed mainly of cellulose, hemicellulose, and lignin. Biomass pretreatment is a required step to make sugar polymers liable to hydrolysis. Mineral acids are commonly used for biomass pretreatment. Using acid catalysts that can be recovered and reused could make the process economically more attractive. The overall goal of this dissertation is the development of a recyclable nanocatalyst for the hydrolysis of biomass sugars. Cobalt iron oxide nanoparticles (CoFe2O4) were synthesized to provide a magnetic core that could be separated from reaction using a magnetic field and modified to carry acid functional groups. X-ray diffraction (XRD) confirmed the crystal structure was that of cobalt spinel ferrite. CoFe2O4 were covered with silica which served as linker for the acid functions. Silica-coated nanoparticles were functionalized with three different acid functions: perfluoropropyl-sulfonic acid, carboxylic acid, and propyl-sulfonic acid. Transmission electron microscope (TEM) images were analyzed to obtain particle size distributions of the nanoparticles. Total carbon, nitrogen, and sulfur were quantified using an elemental analyzer. Fourier transform infra-red spectra confirmed the presence of sulfonic and carboxylic acid functions and ion-exchange titrations accounted for the total amount of catalytic acid sites per nanoparticle mass. These nanoparticles were evaluated for their performance to hydrolyze the beta-1,4 glycosidic bond of the cellobiose molecule. Propyl-sulfonic (PS) and perfluoropropyl-sulfonic (PFS) acid functionalized nanoparticles catalyzed the hydrolysis of cellobiose significantly better than the control. PS and PFS were also evaluated for their capacity to solubilize wheat straw hemicelluloses and performed better than the control. Although PFS nanoparticles were stronger acid catalysts, the acid functions leached out of the nanoparticle during

The substituent and solvent effects on the antioxidant activity of the ferulic acid derivations

International Nuclear Information System (INIS)

Najafi, M.; Bukhari, S.A.

2014-01-01

The antioxidant activity of ortho and meta substituted ferulic acid derivatives have been investigated in the gas phase and water. The reaction enthalpies of antioxidant activity of studied derivatives have been calculated and compared with corresponding values of ferulic acid. Results show that EWG substituents increase the BDE, IP, while EDG ones cause a rise in the PA. The ferulic acid derivatives with lowest BDE, IP and PA values were identified as the compounds with high antioxidant activity. Results show that the substituents at ortho position have high potential for synthesis of novel ferulic acid derivatives. Results show that ferulic acid derivatives can process their protective role via HAT and SPLET mechanism in gas phase and solvent, respectively. The calculated reaction enthalpies of the substituted ferulic acids have linear dependences with Hammett constants and EHOMO that can be utilized in the selection of suitable substituents for the synthesis of novel antioxidants based on ferulic acid. (author)

Study of acid-base properties in various water-salt and water-organic solvent mixtures; Etude de proprietes acides-bases dans divers melanges eau-sels et eau-solvants organiques

Energy Technology Data Exchange (ETDEWEB)

Lucas, M [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1968-02-01

Acid-base reactions have been studied in water-salt mixtures and water organic solvent-mixtures. It has been possible to find some relations between the displacement of the equilibria and the numerical value of water activity in the mixture. First have been studied some equilibria H{sup +} + B {r_reversible} HB{sup +} in salt-water mixtures and found a relation between the pK{sub A} value, the solubility of the base and water activity. The reaction HO{sup -} + H{sup +} {r_reversible} H{sub 2}O has been investigated and a relation been found between pK{sub i} values, water activity and the molar concentration of the salt in the mixture. This relation is the same for every mixture. Then the same reactions have been studied in organic solvent-water mixtures and a relation found in the first part of the work have been used with success. So it has been possible to explain easily some properties of organic water-mixture as the shape of the curves of the Hammett acidity function Ho. (authors) [French] Nous avons envisage l'etude des reactions acides-bases dans des melanges eau-sels MX et des melanges d'eau et de solvants organiques. Les uns et les autres ont ete choisis de facon a ce que la basicite du solvant ou celle de l'anion X{sup -} soit negligeable devant celle de l'eau dans les melanges consideres. Dans un premier temps nous avons etudie dans les melanges eau-sels MX les equilibres H{sup +} + B {r_reversible} HB{sup +} et HA {r_reversible} H{sup +} + A{sup -}. On montre que connaissant la valeur de la solubilite de la base B et de l'acide HA dans le melange eau-sel considere et dans l'eau pure et celle de l'activite de l'eau dans le melange, il est possible de prevoir la valeur de la constante de l'equilibre acide-base etudiee. Dans un deuxieme temps nous avons cherche a generaliser ces resultats, lorsque l'on remplace le sel MX dans le melange avec l'eau par un solvant organique. De meme que precedemment, nous avons compare les constantes d'equilibre du type HB

Acid monolayer functionalized iron oxide nanoparticle catalysts

Science.gov (United States)

Ikenberry, Myles

Superparamagnetic iron oxide nanoparticle functionalization is an area of intensely active research, with applications across disciplines such as biomedical science and heterogeneous catalysis. This work demonstrates the functionalization of iron oxide nanoparticles with a quasi-monolayer of 11-sulfoundecanoic acid, 10-phosphono-1-decanesulfonic acid, and 11-aminoundecanoic acid. The carboxylic and phosphonic moieties form bonds to the iron oxide particle core, while the sulfonic acid groups face outward where they are available for catalysis. The particles were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), potentiometric titration, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectrometry (XPS), and dynamic light scattering (DLS). The sulfonic acid functionalized particles were used to catalyze the hydrolysis of sucrose at 80° and starch at 130°, showing a higher activity per acid site than the traditional solid acid catalyst Amberlyst-15, and comparing well against results reported in the literature for sulfonic acid functionalized mesoporous silicas. In sucrose catalysis reactions, the phosphonic-sulfonic nanoparticles (PSNPs) were seen to be incompletely recovered by an external magnetic field, while the carboxylic-sulfonic nanoparticles (CSNPs) showed a trend of increasing activity over the first four recycle runs. Between the two sulfonic ligands, the phosphonates produced a more tightly packed monolayer, which corresponded to a higher sulfonic acid loading, lower agglomeration, lower recoverability through application of an external magnetic field, and higher activity per acid site for the hydrolysis of starch. Functionalizations with 11-aminoundecanoic acid resulted in some amine groups binding to the surfaces of iron oxide nanoparticles. This amine binding is commonly ignored in iron oxide

Synthesis, Acidity Constants and Tautomeric Structure of the Diazonium Coupling Products of 2-(Benzylsulfanyl-7H-purin-6-one in Its Ground and Excited States

Directory of Open Access Journals (Sweden)

Hosam A. Saad

2011-10-01

Full Text Available A series of new 8-arylhydrazono-2-(benzylsulfanyl-7H-purin-6-ones 6 were synthesized, their electronic absorption spectra in different organic solvents of varying polarities were investigated and their acid dissociation constants in both the ground and excited states were determined spectrophotometrically. The tautomeric structures of such products were elucidated by spectral analyses and correlation of their acid dissociation constants with the Hammett equation. The results indicated that the studied compounds 6 exist predominantly in the hydrazone tautomeric form 6A in both the ground and excited states.

Acid-functionalized polyolefin materials and their use in acid-promoted chemical reactions

Science.gov (United States)

Oyola, Yatsandra; Tian, Chengcheng; Bauer, John Christopher; Dai, Sheng

2016-06-07

An acid-functionalized polyolefin material that can be used as an acid catalyst in a wide range of acid-promoted chemical reactions, wherein the acid-functionalized polyolefin material includes a polyolefin backbone on which acid groups are appended. Also described is a method for the preparation of the acid catalyst in which a precursor polyolefin is subjected to ionizing radiation (e.g., electron beam irradiation) of sufficient power and the irradiated precursor polyolefin reacted with at least one vinyl monomer having an acid group thereon. Further described is a method for conducting an acid-promoted chemical reaction, wherein an acid-reactive organic precursor is contacted in liquid form with a solid heterogeneous acid catalyst comprising a polyolefin backbone of at least 1 micron in one dimension and having carboxylic acid groups and either sulfonic acid or phosphoric acid groups appended thereto.

31P NMR Chemical Shifts of Phosphorus Probes as Reliable and Practical Acidity Scales for Solid and Liquid Catalysts.

Science.gov (United States)

Zheng, Anmin; Liu, Shang-Bin; Deng, Feng

2017-10-11

Acid-base catalytic reaction, either in heterogeneous or homogeneous systems, is one of the most important chemical reactions that has provoked a wide variety of industrial catalytic processes for production of chemicals and petrochemicals over the past few decades. In view of the fact that the catalytic performances (e.g., activity, selectivity, and reaction mechanism) of acid-catalyzed reactions over acidic catalysts are mostly dictated by detailed acidic features, viz. type (Brønsted vs Lewis acidity), amount (concentration), strength, and local environments (location) of acid sites, information on and manipulation of their structure-activity correlation are crucial for optimization of catalytic performances as well as innovative design of novel effective catalysts. This review aims to summarize recent developments on acidity characterization of solid and liquid catalysts by means of experimental 31 P nuclear magnetic resonance (NMR) spectroscopy using phosphorus probe molecules such as trialkylphosphine (TMP) and trialkylphosphine oxides (R 3 PO). In particular, correlations between the observed 31 P chemical shifts (δ 31 P) of phosphorus (P)-containing probes and acidic strengths have been established in conjuction with density functional theory (DFT) calculations, rendering practical and reliable acidity scales for Brønsted and Lewis acidities at the atomic level. As illustrated for a variety of different solid and liquid acid systems, such as microporous zeolites, mesoporous molecular sieves, and metal oxides, the 31 P NMR probe approaches were shown to provide important acid features of various catalysts, surpassing most conventional methods such as titration, pH measurement, Hammett acidity function, and some other commonly used physicochemical techniques, such as calorimetry, temperature-programmed desorption of ammonia (NH 3 -TPD), Fourier transformed infrared (FT-IR), and 1 H NMR spectroscopies.

Influence of the anodizing process variables on the acidic properties of anodic alumina films

Directory of Open Access Journals (Sweden)

D.E. Boldrini

Full Text Available Abstract In the present work, the effect of the different variables involved in the process of aluminum anodizing on the total surface acidity of the samples obtained was studied. Aluminum foils were treated by the electro-chemical process of anodic anodizing within the following variable ranges: concentration = 1.5-2.5 M; temperature = 303-323 K; voltage = 10-20 V; time = 30-90 min. The total acidity of the samples was characterized by two different methods: acid-base titration using Hammett indicators and potentiometric titration. The results showed that anodizing time, temperature and concentration were the main variables that determined the surface acid properties of the samples, and to a lesser extent voltage. Acidity increased with increasing concentration of the electrolytic bath, whereas the rest of the variables had the opposite effect. The results obtained provide a novel tool for variable selection in order to use synthetized materials as catalytic supports, adding to previous research based on the morphology of alumina layers.

Eicosahexanoic Acid (EPA and Docosahexanoic Acid (DHA in Muscle Damage and Function

Directory of Open Access Journals (Sweden)

Eisuke Ochi

2018-04-01

Full Text Available Nutritional supplementation not only helps in improving and maintaining performance in sports and exercise, but also contributes in reducing exercise fatigue and in recovery from exhaustion. Fish oil contains large amounts of omega-3 fatty acids, eicosapentaenoic acid (EPA; 20:5 n-3 and docosahexaenoic acid (DHA; 22:6 n-3. It is widely known that omega-3 fatty acids are effective for improving cardiac function, depression, cognitive function, and blood as well as lowering blood pressure. In the relationship between omega-3 fatty acids and exercise performance, previous studies have been predicted improved endurance performance, antioxidant and anti-inflammatory responses, and effectivity against delayed-onset muscle soreness. However, the optimal dose, duration, and timing remain unclear. This review focuses on the effects of omega-3 fatty acid on muscle damage and function as evaluated by human and animal studies and summarizes its effects on muscle and nerve damage, and muscle mass and strength.

Electron inductive effects in the radiolysis of substituted phenylboronic acid solutions

International Nuclear Information System (INIS)

Brown, B.J.; Fitch, P.G.; Sangster, D.F.

1976-01-01

The pulse radiolysis of aqueous solutions of phenylboronic acid PhB(OH) 2 and its m-nitro and m-amino derivatives has been investigated. The transient optical absorption spectra indicate the presence of three intermediate species absorbing with independent maxima at 297, 317 and 400 nm. The 297-nm band has been assigned to the anion formed in an electron capture reaction, i.e. PhB(OH) 2 +epsilonsub(aq) - → PhB(OH) 2 - and the 317-nm band to cyclohexadienyl radicals formed from OH and H attack on OhB(OH) 2 . Hydroxyphenylboronic acid has been identified as the major stable radiation product. For each of the systems studied the respective yield and reactivity of observed intermediate species can be interpreted relative to the inductive effects of substituent groups in agreement with the Hammett relationship. (author)

Mechanism of Oxidation of (p-Substituted Phenylthioacetic Acids with N-Chlorosaccharin

Directory of Open Access Journals (Sweden)

N. M. I. Alhaj

2011-01-01

Full Text Available The kinetics of oxidation of (phenylthioacetic acid (PTAA with N-chlorosaccharin (NCSA have been studied potentiometrically in 80:20 (v/v acetonitrile-water medium at 298 K. The reaction is first-order each with respect to PTAA and NCSA and shows a negative dependence on [H+]. NCSA itself is shown to be the active oxidizing species. Effects of ionic strength variation, added saccharin, added acrylonitrile, added NaCl and solvent composition variation have been studied. Effect of substituents on the reaction rate has been analysed by employing various (p-sustituted phenylthioacetic acids. The electron-releasing substituent in the phenyl ring of PTAA accelerates the reaction rate while the electron-withdrawing substituent retards the rate. The excellently linear Hammett plot yields a large negative ρ value, supporting the involvement a chlorosulphonium ion intermediate in the rate-determining step.

Biological response to purification and acid functionalization of carbon nanotubes

Science.gov (United States)

Figarol, Agathe; Pourchez, Jérémie; Boudard, Delphine; Forest, Valérie; Tulliani, Jean-Marc; Lecompte, Jean-Pierre; Cottier, Michèle; Bernache-Assollant, Didier; Grosseau, Philippe

2014-07-01

Acid functionalization has been considered as an easy way to enhance the dispersion and biodegradation of carbon nanotubes (CNT). However, inconsistencies between toxicity studies of acid functionalized CNT remain unexplained. This could be due to a joint effect of the main physicochemical modifications resulting from an acid functionalization: addition of surface acid groups and purification from catalytic metallic impurities. In this study, the impact on CNT biotoxicity of these two physiochemical features was assessed separately. The in vitro biological response of RAW 264.7 macrophages was evaluated after exposure to 15-240 µg mL-1 of two types of multi-walled CNT. For each type of CNT (small: 20 nm diameter, and big: 90 nm diameter), three different surface chemical properties were studied (total of six CNT samples): pristine, acid functionalized and desorbed. Desorbed CNT were purified by the acid functionalization but presented a very low amount of surface acid groups due to a thermal treatment under vacuum. A Janus effect of acid functionalization with two opposite impacts is highlighted. The CNT purification decreased the overall toxicity, while the surface acid groups intensified it when present at a specific threshold. These acid groups especially amplified the pro-inflammatory response. The threshold mechanism which seemed to regulate the impact of acid groups should be further studied to determine its value and potential link to the other physicochemical state of the CNT. The results suggest that, for a safer-design approach, the benefit-risk balance of an acid functionalization has to be considered, depending on the CNT primary state of purification. Further research should be conducted in this direction.

Dietary fatty acids and membrane protein function.

Science.gov (United States)

Murphy, M G

1990-02-01

In recent years, there has been growing public awareness of the potential health benefits of dietary fatty acids, and of the distinction between the effects of the omega6 and omega3 polyunsaturated fatty acids that are concentrated in vegetable and fish oils, respectively. A part of the biologic effectiveness of the two families of polyunsaturated fatty acids resides in their relative roles as precursors of the eicosanoids. However, we are also beginning to appreciate that as the major components of the hydrophobic core of the membrane bilayer, they can interact with and directly influence the functioning of select integral membrane proteins. Among the most important of these are the enzymes, receptors, and ion channels that are situated in the plasma membrane of the cell, since they carry out the communication and homeostatic processes that are necessary for normal cell function. This review examines current information regarding the effects of diet-induced changes in plasma membrane fatty acid composition on several specific enzymes (adenylate cyclase, 5'-nucleotidase, Na(+)/K(+)-ATPase) and cell-surface receptors (opiate, adrenergic, insulin). Dietary manipulation studies have demonstrated a sensitivity of each to a fatty acid environment that is variably dependent on the nature of the fatty acid(s) and/or source of the membrane. The molecular mechanisms appear to involve fatty acid-dependent effects on protein conformation, on the "fluidity" and/or thickness of the membrane, or on protein synthesis. Together, the results of these studies reinforce the concept that dietary fats have the potential to regulate physiologic function and to further our understanding of how this occurs at a membrane level.

Competitive/co-operative interactions in acid base sandwich: role of cation vs. substituents.

Science.gov (United States)

Kalpana, Ayyavoo; Akilandeswari, Lakshminarayanan

2017-11-15

The cation-π interaction can be envisaged as a lewis acid base interaction, and it is in line with Pearson's acid base concept. The critical examination of interactions between the π-acids (alkali metal cations - Li + , Na + and alkaline earth metal cations Mg 2+ , Ca 2+ ) on one face and tripodal Cr(CO) 3 moiety on the other π face of substituted arenes demonstrates the role of cation and substitutents in manipulating the interactions between them. The interaction of the two π acids on both faces of arene is not expectedly additive, rather it shows either depreciation of interaction energy revealing the competition of acids toward the base or enhancement of interaction energy denoting a cooperative effect. Among the metal cations under study, Mg 2+ shows a cooperative gesture. Although the substituents play a meek role, they unfailingly exert their electronic effects and are amply documented by excellent correlation of various parameters with the Hammett constant σ m . The elusive switching of λ max from the UV to IR region on binding Mg 2+ with substituted arene-Cr(CO) 3 complex is a characteristic clue that TDDFT can help design the ionic sensors for Mg 2+ cations.

Covalently functionalized graphene sheets with biocompatible natural amino acids

International Nuclear Information System (INIS)

Mallakpour, Shadpour; Abdolmaleki, Amir; Borandeh, Sedigheh

2014-01-01

Graphene sheets were covalently functionalized with aromatic–aliphatic amino acids (phenylalanine and tyrosine) and aliphatic amino acids (alanine, isoleucine, leucine, methionine and valine) by simple and green procedure. For this aim, at first natural graphite was converted into graphene oxide (GO) through strong oxidation procedure; then, based on the surface-exposed epoxy and carboxylic acid groups in GO solid, its surface modification with naturally occurring amino acids, occurred easily throughout the corresponding nucleophilic substitution and condensation reactions. Amino acid functionalized graphene demonstrates stable dispersion in water and common organic solvents. Fourier transform infrared, Raman and X-ray photoelectron spectroscopies, X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy were used to investigate the nanostructures and properties of prepared materials. Each amino acid has different considerable effects on the structure and morphology of the pure graphite, from increasing the layer spacing to layer scrolling, based on their structures, functional groups and chain length. In addition, therogravimetric analysis was used for demonstrating a successful grafting of amino acid molecules to the surface of graphene.

Fatty Acids, Lipid Mediators, and T-Cell Function

Science.gov (United States)

de Jong, Anja J.; Kloppenburg, Margreet; Toes, René E. M.; Ioan-Facsinay, Andreea

2014-01-01

Research toward the mechanisms underlying obesity-linked complications has intensified during the last years. As a consequence, it has become clear that metabolism and immunity are intimately linked. Free fatty acids and other lipids acquired in excess by current feeding patterns have been proposed to mediate this link due to their immune modulatory capacity. The functional differences between saturated and unsaturated fatty acids, in combination with their dietary intake are believed to modulate the outcome of immune responses. Moreover, unsaturated fatty acids can be oxidized in a tightly regulated and specific manner to generate either potent pro-inflammatory or pro-resolving lipid mediators. These oxidative derivatives of fatty acids have received detailed attention during the last years, as they have proven to have strong immune modulatory capacity, even in pM ranges. Both fatty acids and oxidized fatty acids have been studied especially in relation to macrophage and T-cells functions. In this review, we propose to focus on the effect of fatty acids and their oxidative derivatives on T-cells, as it is an active area of research during the past 5 years. The effect of fatty acids and their derivatives on activation and proliferation of T-cells, as well as the delicate balance between stimulation and lipotoxicity will be discussed. Moreover, the receptors involved in the interaction between free fatty acids and their derivatives with T-cells will be summarized. Finally, the mechanisms involved in modulation of T-cells by fatty acids will be addressed, including cellular signaling and metabolism of T-cells. The in vitro results will be placed in context of in vivo studies both in humans and mice. In this review, we summarize the latest findings on the immune modulatory function of lipids on T-cells and will point out novel directions for future research. PMID:25352844

Accurate core-electron binding energy shifts from density functional theory

International Nuclear Information System (INIS)

Takahata, Yuji; Marques, Alberto Dos Santos

2010-01-01

Current review covers description of density functional methods of calculation of accurate core-electron binding energy (CEBE) of second and third row atoms; applications of calculated CEBEs and CEBE shifts (ΔCEBEs) in elucidation of topics such as: hydrogen-bonding, peptide bond, polymers, DNA bases, Hammett substituent (σ) constants, inductive and resonance effects, quantitative structure activity relationship (QSAR), and solid state effect (WD). This review limits itself to works of mainly Chong and his coworkers for the period post-2002. It is not a fully comprehensive account of the current state of the art.

Synthesis and characterization of carboxylic acid functionalized silicon nanoparticles

Science.gov (United States)

Shaner, Ted V.

Silicon nanoparticles are of great interest in a great number of fields. Silicon nanoparticles show great promise particularly in the field of bioimaging. Carboxylic acid functionalized silicon nanoparticles have the ability to covalently bond to biomolecules through the conjugation of the carboxylic acid to an amine functionalized biomolecule. This thesis explores the synthesis of silicon nanoparticles functionalized by both carboxylic acids and alkenes and their carboxylic acid functionality. Also discussed is the characterization of the silicon nanoparticles by the use of x-ray spectroscopy. Finally, the nature of the Si-H bond that is observed on the surface of the silicon nanoparticles will be investigated using photoassisted exciton mediated hydrosilation reactions. The silicon nanoparticles are synthesized from both carboxylic acids and alkenes. However, the lack of solubility of diacids is a significant barrier to carboxylic acid functionalization by a mixture of monoacids and diacids. A synthesis route to overcome this obstacle is to synthesize silicon nanoparticles with terminal vinyl group. This terminal vinyl group is distal to the surface of the silicon nanoparticle. The conversion of the vinyl group to a carboxylic acid is accomplished by oxidative cleavage using ozonolysis. The carboxylic acid functionalized silicon nanoparticles were then successfully conjugated to amine functionalized DNA strand through an n-hydroxy succinimide ester activation step, which promotes the formation of the amide bond. Conjugation was characterized by TEM and polyacrylamide gel electrophoresis (PAGE). The PAGE results show that the silicon nanoparticle conjugates move slower through the polyacrylamide gel, resulting in a significant separation from the nonconjugated DNA. The silicon nanoparticles were then characterized by the use of x-ray absorption near edge spectroscopy (Xanes) and x-ray photoelectron spectroscopy (XPS) to investigate the bonding and chemical

Mechanism of Oxidation of (p-Substituted Phenylthioacetic Acids with N-Bromophthalimide

Directory of Open Access Journals (Sweden)

N. M. I. Alhaji

2011-01-01

Full Text Available The kinetics of oxidation of (phenylthioacetic acid (PTAA by N-Bromophthalimide (NBP in acetonitrile-water solvent mixture at 298 K in the presence of perchloric acid has been followed potentiometrically. The reaction is first-order each in NBP and PTAA and inverse fractional-order in H+. Also, it has been found that the reaction rate is not affected by changes in ionic strength of the reaction medium or by the addition of chemicals such as phthalimide, acrylonitrile and potassium bromide. However, an increase in the water content of the solvent mixture causes an increase in the rate of reaction. These observations have been well analyzed in favour of a SN2-type mechanism, involving NBP itself as the reactive species. Effect of substituents on the reaction rate has been analysed by employing various (p-sustituted phenylthioacetic acids. The electron-releasing substituent in the phenyl ring of PTAA accelerates the reaction rate while the electron-withdrawing substituent retards the rate. The excellently linear Hammett plot yields a large negative ρ value, supporting the involvement a bromosulphonium ion intermediate in the rate-determining step.

Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

Energy Technology Data Exchange (ETDEWEB)

Nan, Alexandrina, E-mail: alexandrina.nan@itim-cj.ro; Bunge, Alexander; Turcu, Rodica [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca (Romania)

2015-12-23

Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

Effect of acid hydrolysis on starch structure and functionality: a review.

Science.gov (United States)

Wang, Shujun; Copeland, Les

2015-01-01

Acid hydrolysis is an important chemical modification that can significantly change the structural and functional properties of starch without disrupting its granular morphology. A deep understanding of the effect of acid hydrolysis on starch structure and functionality is of great importance for starch scientific research and its industrial applications. During acid hydrolysis, amorphous regions are hydrolyzed preferentially, which enhances the crystallinity and double helical content of acid hydrolyzed starch. This review discusses current understanding of the effect of acid hydrolysis on starch structure and functionality. The effects of acid hydrolysis on amylose content, chain length distribution of amylopectin molecules, molecular and crystalline organization (including lamellar structure) and granular morphology are considered. Functional properties discussed include swelling power, gelatinization, retrogradation, pasting, gel texture, and in vitro enzyme digestibility. The paper also highlights some promising applications of acid hydrolyzed starch (starch nanocrystals) in the preparation of biodegradable nanocomposites, bio-hydrogen, and slowly digestible starch-based healthy foods.

Chemical functionalization of hyaluronic acid for drug delivery applications

Energy Technology Data Exchange (ETDEWEB)

Vasi, Ana-Maria [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73 Prof. dr. docent Dimitrie Mangeron Street, 700050 Iasi (Romania); Popa, Marcel Ionel, E-mail: mipopa@ch.tuiasi.ro [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73 Prof. dr. docent Dimitrie Mangeron Street, 700050 Iasi (Romania); Butnaru, Maria [“Grigore T. Popa” University of Medicine Pharmacy, Faculty of Medical Bioengineering, 9-13 Kogalniceanu Street, 700454 Iasi (Romania); Dodi, Gianina [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73 Prof. dr. docent Dimitrie Mangeron Street, 700050 Iasi (Romania); SCIENT — Research Center for Instrumental Analysis, S.C. CROMATEC PLUS, 18 Sos. Cotroceni, 060114 Bucharest (Romania); Verestiuc, Liliana [“Grigore T. Popa” University of Medicine Pharmacy, Faculty of Medical Bioengineering, 9-13 Kogalniceanu Street, 700454 Iasi (Romania)

2014-05-01

Functionalized hyaluronic acid (HA) derivatives were obtained by ring opening mechanism of maleic anhydride (MA). FTIR and H{sup 1} NMR spectroscopy were used to confirm the chemical linkage of MA on the hyaluronic acid chains. Thermal analysis (TG-DTG and DSC) and GPC data for the new products revealed the formation of new functional groups, without significant changes in molecular weight and thermal stability. New gels based on hyaluronic acid modified derivatives were obtained by acrylic acid copolymerization in the presence of a redox initiation system. The resulted circular and interconnected pores of the gels were visualized by SEM. The release profiles of an ophthalmic model drug, pilocarpine from tested gels were studied in simulated media. Evaluation of the cytotoxicity and cell proliferation properties indicates the potential of the new systems to be used in contact with biological media in drug delivery applications. - Highlights: • New functionalized hyaluronic acid was prepared by ring opening of maleic anhydride. • Gels with circular pores based on acrylic acid copolymerization were formulated. • In vitro drug loading/release profile was evaluated in simulated ophthalmic media. • The cytotoxicity indicates the potential of derivatives to be used in vivo.

SOCl2 CATALYZED CYCLIZATION OF CHALCONES: SYNTHESIS ...

African Journals Online (AJOL)

Preferred Customer

synthesised pyrazolines have been studied using Bauer-Kirby method. .... was separated with dichloromethane and the solid product was obtained on evaporation. ...... Hammett σ constants in alkenes, alkynes, acid chlorides and styrenes.

Co2 chemosorption by functionalized amino acid derivatives

DEFF Research Database (Denmark)

2015-01-01

The absorption and desorption behaviour of carbon dioxide (CO2) using a composition comprising an ionic compound comprising a cation [A+] and an anion [B-] is described, wherein the anion [B-] is a mono-amine functionalized amino acid.......The absorption and desorption behaviour of carbon dioxide (CO2) using a composition comprising an ionic compound comprising a cation [A+] and an anion [B-] is described, wherein the anion [B-] is a mono-amine functionalized amino acid....

Functionalized carbon nanofibers as solid acid catalysts for transesterification

NARCIS (Netherlands)

Stellwagen, D.R.; van der Klis, Frits; van Es, D.S.; de Jong, K.P.; Bitter, J.H.

2013-01-01

Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient

Functionalized carbon nanofibers as solid-acid catalysts for transesterification

NARCIS (Netherlands)

Stellwagen, D.R.; Klis, van der F.; Es, van D.S.; Jong, de K.P.; Bitter, J.H.

2013-01-01

Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient

New Functions and Potential Applications of Amino Acids.

Science.gov (United States)

Uneyama, Hisayuki; Kobayashi, Hisamine; Tonouchi, Naoto

Currently, several types of amino acids are being produced and used worldwide. Nevertheless, several new functions of amino acids have been recently discovered that could result in other applications. For example, oral stimulation by glutamate triggers the cephalic phase response to prepare for food digestion. Further, the stomach and intestines have specific glutamate-recognizing systems in their epithelial mucosa. Regarding clinical applications, addition of monosodium glutamate to the medicinal diet has been shown to markedly enhance gastric secretion in a vagus-dependent manner. Branched-chain amino acids (BCAAs) are the major components of muscles, and ingestion of BCAAs has been found to be effective for decreasing muscle pain. BCAAs are expected to be a solution for the serious issue of aging. Further, ingestion of specific amino acids could be beneficial. Glycine can be ingested for good night's sleep: glycine ingestion before bedtime significantly improved subjective sleep quality. Ingestion of alanine and glutamine effectively accelerates alcohol metabolism, and ingestion of cystine and theanine effectively prevents colds. Finally, amino acids could be used in a novel clinical diagnostic method: the balance of amino acids in the blood could be an indicator of the risk of diseases such as cancer. These newly discovered functions of amino acids are expected to contribute to the resolution of various issues.

Carboxylic acid-functionalized SBA-15 nanorods for gemcitabine delivery

International Nuclear Information System (INIS)

Bahrami, Zohreh; Badiei, Alireza; Ziarani, Ghodsi Mohammadi

2015-01-01

The present study deals with the functionalization of mesoporous silica nanoparticles as drug delivery systems. Mono, di, and tri amino-functionalized SBA-15 nanorods were synthesized by post-grafting method using (3-aminopropyl) triethoxysilane, N-(2-aminoethyl-)3- aminopropyltrimethoxysilane, and 3-[2-(2-aminoethylamino) ethylamino] propyl trimethoxysilane, respectively. The carboxylic acid derivatives of the amino-functionalized samples were obtained using succinic anhydride. Tminopropyltrimethoxysilanehe obtained modified materials were investigated as matrixes for the anticancer drug (gemcitabine) delivery. The prepared samples were characterized by SAXS, N 2 adsorption/desorption, SEM, transmission electron microscopy, thermogravimetric analysis, and FTIR and UV spectroscopies. The adsorption and release properties of all samples were studied. It was revealed that the adsorption capacity and release behavior of gemcitabine were highly dependent on the type of the introduced functional groups. The carboxylic acid-modified samples have higher loading content, due to the strong interaction with gemcitabine. The maximum content of deposited drug in the modified SBA-15 nanorods is close to 40 wt%. It was found that the surface functionalization leads toward significant decrease of the drug release rate. The carboxylic acid-functionalized samples have slower release rate in contrast with the amino-functionalized samples

Functions and Signaling Pathways of Amino Acids in Intestinal Inflammation

Directory of Open Access Journals (Sweden)

Fang He

2018-01-01

Full Text Available Intestine is always exposed to external environment and intestinal microorganism; thus it is more sensitive to dysfunction and dysbiosis, leading to intestinal inflammation, such as inflammatory bowel disease (IBD, irritable bowel syndrome (IBS, and diarrhea. An increasing number of studies indicate that dietary amino acids play significant roles in preventing and treating intestinal inflammation. The review aims to summarize the functions and signaling mechanisms of amino acids in intestinal inflammation. Amino acids, including essential amino acids (EAAs, conditionally essential amino acids (CEAAs, and nonessential amino acids (NEAAs, improve the functions of intestinal barrier and expressions of anti-inflammatory cytokines and tight junction proteins but decrease oxidative stress and the apoptosis of enterocytes as well as the expressions of proinflammatory cytokines in the intestinal inflammation. The functions of amino acids are associated with various signaling pathways, including mechanistic target of rapamycin (mTOR, inducible nitric oxide synthase (iNOS, calcium-sensing receptor (CaSR, nuclear factor-kappa-B (NF-κB, mitogen-activated protein kinase (MAPK, nuclear erythroid-related factor 2 (Nrf2, general controlled nonrepressed kinase 2 (GCN2, and angiotensin-converting enzyme 2 (ACE2.

Nucleic acid-functionalized transition metal nanosheets for biosensing applications.

Science.gov (United States)

Mo, Liuting; Li, Juan; Liu, Qiaoling; Qiu, Liping; Tan, Weihong

2017-03-15

In clinical diagnostics, as well as food and environmental safety practices, biosensors are powerful tools for monitoring biological or biochemical processes. Two-dimensional (2D) transition metal nanomaterials, including transition metal chalcogenides (TMCs) and transition metal oxides (TMOs), are receiving growing interest for their use in biosensing applications based on such unique properties as high surface area and fluorescence quenching abilities. Meanwhile, nucleic acid probes based on Watson-Crick base-pairing rules are also being widely applied in biosensing based on their excellent recognition capability. In particular, the emergence of functional nucleic acids in the 1980s, especially aptamers, has substantially extended the recognition capability of nucleic acids to various targets, ranging from small organic molecules and metal ions to proteins and cells. Based on π-π stacking interaction between transition metal nanosheets and nucleic acids, biosensing systems can be easily assembled. Therefore, the combination of 2D transition metal nanomaterials and nucleic acids brings intriguing opportunities in bioanalysis and biomedicine. In this review, we summarize recent advances of nucleic acid-functionalized transition metal nanosheets in biosensing applications. The structure and properties of 2D transition metal nanomaterials are first discussed, emphasizing the interaction between transition metal nanosheets and nucleic acids. Then, the applications of nucleic acid-functionalized transition metal nanosheet-based biosensors are discussed in the context of different signal transducing mechanisms, including optical and electrochemical approaches. Finally, we provide our perspectives on the current challenges and opportunities in this promising field. Copyright © 2016 Elsevier B.V. All rights reserved.

Pd(II)-catalysed meta-C–H functionalizations of benzoic acid derivatives

Science.gov (United States)

Li, Shangda; Cai, Lei; Ji, Huafang; Yang, Long; Li, Gang

2016-01-01

Benzoic acids are highly important structural motifs in drug molecules and natural products. Selective C–H bond functionalization of benzoic acids will provide synthetically useful tools for step-economical organic synthesis. Although direct ortho-C–H functionalizations of benzoic acids or their derivatives have been intensely studied, the ability to activate meta-C–H bond of benzoic acids or their derivatives in a general manner via transition-metal catalysis has been largely unsuccessful. Although chelation-assisted meta-C–H functionalization of electron-rich arenes was reported, chelation-assisted meta-C–H activation of electron-poor arenes such as benzoic acid derivatives remains a formidable challenge. Herein, we report a general protocol for meta-C–H olefination of benzoic acid derivatives using a nitrile-based sulfonamide template. A broad range of benzoic acid derivatives are meta-selectively olefinated using molecular oxygen as the terminal oxidant. The meta-C–H acetoxylation, product of which is further transformed at the meta-position, is also reported. PMID:26813919

Biological functions of iduronic acid in chondroitin/dermatan sulfate.

Science.gov (United States)

Thelin, Martin A; Bartolini, Barbara; Axelsson, Jakob; Gustafsson, Renata; Tykesson, Emil; Pera, Edgar; Oldberg, Åke; Maccarana, Marco; Malmstrom, Anders

2013-05-01

The presence of iduronic acid in chondroitin/dermatan sulfate changes the properties of the polysaccharides because it generates a more flexible chain with increased binding potentials. Iduronic acid in chondroitin/dermatan sulfate influences multiple cellular properties, such as migration, proliferation, differentiation, angiogenesis and the regulation of cytokine/growth factor activities. Under pathological conditions such as wound healing, inflammation and cancer, iduronic acid has diverse regulatory functions. Iduronic acid is formed by two epimerases (i.e. dermatan sulfate epimerase 1 and 2) that have different tissue distribution and properties. The role of iduronic acid in chondroitin/dermatan sulfate is highlighted by the vast changes in connective tissue features in patients with a new type of Ehler-Danlos syndrome: adducted thumb-clubfoot syndrome. Future research aims to understand the roles of the two epimerases and their interplay with the sulfotransferases involved in chondroitin sulfate/dermatan sulfate biosynthesis. Furthermore, a better definition of chondroitin/dermatan sulfate functions using different knockout models is needed. In this review, we focus on the two enzymes responsible for iduronic acid formation, as well as the role of iduronic acid in health and disease. © 2013 The Authors Journal compilation © 2013 FEBS.

Effect of amino acid-functionalized multi-walled carbon nanotubes ...

Indian Academy of Sciences (India)

In a single-step, rapid microwave-assisted process, multi-walled carbon nanotubes were functionalized by -valine amino acid. Formation of amino acid on nanotube surface was confirmed by Fourier transform-infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, field emission scanning and transmission ...

Fatty Acid Signaling: The New Function of Intracellular Lipases

Directory of Open Access Journals (Sweden)

Zuzana Papackova

2015-02-01

Full Text Available Until recently, intracellular triacylglycerols (TAG stored in the form of cytoplasmic lipid droplets have been considered to be only passive “energy conserves”. Nevertheless, degradation of TAG gives rise to a pleiotropic spectrum of bioactive intermediates, which may function as potent co-factors of transcription factors or enzymes and contribute to the regulation of numerous cellular processes. From this point of view, the process of lipolysis not only provides energy-rich equivalents but also acquires a new regulatory function. In this review, we will concentrate on the role that fatty acids liberated from intracellular TAG stores play as signaling molecules. The first part provides an overview of the transcription factors, which are regulated by fatty acids derived from intracellular stores. The second part is devoted to the role of fatty acid signaling in different organs/tissues. The specific contribution of free fatty acids released by particular lipases, hormone-sensitive lipase, adipose triacylglycerol lipase and lysosomal lipase will also be discussed.

Bile acids and cardiovascular function in cirrhosis

DEFF Research Database (Denmark)

Voiosu, Andrei; Wiese, Signe; Voiosu, Theodor

2017-01-01

Cirrhotic cardiomyopathy and the hyperdynamic syndrome are clinically important complications of cirrhosis, but their exact pathogenesis is still partly unknown. Experimental models have proven the cardiotoxic effects of bile acids and recent studies of their varied receptor-mediated functions...... offer new insight into their involvement in cardiovascular dysfunction in cirrhosis. Bile acid receptors such as farnesoid X-activated receptor and TGR5 are currently under investigation as potential therapeutic targets in a variety of pathological conditions. These receptors have also recently been...... identified in cardiomyocytes, vascular endothelial cells and smooth muscle cells where they seem to play an important role in cellular metabolism. Chronic cholestasis leading to abnormal levels of circulating bile acids alters the normal signalling pathways and contributes to the development of profound...

Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction

Directory of Open Access Journals (Sweden)

Vicky Gheerardijn

2014-11-01

Full Text Available Functionalized oligonucleotides have recently gained increased attention for incorporation in modified nucleic acid structures both for the design of aptamers with enhanced binding properties as well as the construction of catalytic DNA and RNA. As a shortcut alternative to the incorporation of multiple modified residues, each bearing one extra functional group, we present here a straightforward method for direct linking of functionalized amino acids to the nucleoside base, thus equipping the nucleoside with two extra functionalities at once. As a proof of principle, we have introduced three amino acids with functional groups frequently used as key-intermediates in DNA- and RNAzymes via an efficient and straightforward domino carboxamidation reaction.

Relationship Between Dietary Fatty Acids and Reproductive Functions in Dairy Cattle

Directory of Open Access Journals (Sweden)

Ercan Soydan

2017-12-01

Full Text Available Selection of dairy cattle for higher milk yield, without considering important non-production traits, has decreased reproductive efficiency. Thus, low reproductive performance is a major problem in high yielding dairy cattle. Previous studies showed that dietary manipulation to improve fertility holds much promise and dietary fats have positive effects on reproductive functions in high yielding dairy cattle. Positive effects of fats on reproductive performance due to the fatty acids, which are the precursors of progesterone and prostaglandins. Progesterone and prostaglandins hormones are most important factors that play a role on the control of reproductive functions. The amount of linoleic, linolenic and arachidonic fattty acids in ration can be increase or decrease progesterone and prostaglandins synthesis especially PGF2α from ovary and uterus, respectively. Also fatty acids can be influence follicular development, ovulation, embryonic implantation and maternal recognition of pregnancy. This review focuses on the relationships between dietary fatty acids and reproductive functions such as hormone profiles, ovarian function and follicular development, oocyte quality, embryo development, embryonic implantation and maternal recognition of pregnancy in dairy cattle.

Identification of Novel Functional Inhibitors of Acid Sphingomyelinase

DEFF Research Database (Denmark)

Kornhuber, Johannes; Muehlbacher, Markus; Trapp, Stefan

2011-01-01

of ASM, such as Alzheimer's disease, major depression, radiation-and chemotherapy-induced apoptosis and endotoxic shock syndrome. Residual activity of ASM measured in the presence of 10 mu M drug concentration shows a bimodal distribution; thus the tested drugs can be classified into two groups......We describe a hitherto unknown feature for 27 small drug-like molecules, namely functional inhibition of acid sphingomyelinase (ASM). These entities named FIASMAs (Functional Inhibitors of Acid SphingoMyelinAse), therefore, can be potentially used to treat diseases associated with enhanced activity...... with lower and higher inhibitory activity. All FIASMAs share distinct physicochemical properties in showing lipophilic and weakly basic properties. Hierarchical clustering of Tanimoto coefficients revealed that FIASMAs occur among drugs of various chemical scaffolds. Moreover, FIASMAs more frequently violate...

Effects of solvent and structure on the reactivity of 6-substituted nicotinic acids with diazodiphenylmethane in aprotic solvents

Directory of Open Access Journals (Sweden)

BRATISLAV Ž. JOVANOVIĆ

2009-12-01

Full Text Available The rate constants for the reactions of diazodiphenylmethane (DDM with 6-substituted nicotinic acids in aprotic solvents at 30 °C were determined. The obtained second order rate constants in aprotic solvents, together with literature data for benzoic and nicotinic acids in protic solvents, were used for the calculation of solvent effects, employing the Kamlet-Taft solvatochromic equation (linear solvation energy relationship – LSER in the form: log k = log k0 + s* + a + b. The correlations of the kinetic data were performed by means of multiple linear regression analysis taking appropriate solvent parameters. The sign of the equation coefficients (s, a and b were in agreement with the postulated reaction mechanism, and the mode of the solvent influences on the reaction rate is discussed based on the correlation results. A similar contribution of the non-specific solvent effect and electrophilic solvation was observed for all acids, while the highest contribution of nucleophilic solvation was influenced by their high acidity. Correlation analysis of the rate data with substituent p parameters in an appropriate solvent using the Hammett equation was also performed. The substituent effect on the acid reactivity was higher in aprotic solvents of higher dipolarity/polarizability. The mode of the transmission of the substituent effect is discussed in light of the contribution of solute–solvent interaction on the acid reactivity.

Amide and Ester-Functionalized Humic Acid for Fuel Combustion Enhancement

Science.gov (United States)

Riggs, Mark

Humic acid is a class of naturally occurring molecules composed of large sheet-like regions of cyclic aromatic hydrocarbon networks with surface and edge functional groups including phenols, carboxylic acids, and epoxides. These naturally occurring molecules are found in brown coal deposits near lignite formations. Humic acid has gained attention from the scientific community as a precursor for graphene. Graphene is a 2-dimensional honeycomb structure of fully unsaturated carbon atoms that has exceptional material properties and inherent aromaticity. Graphene's incredible properties are matched by the difficulty associated with reproducibly manufacturing it on a large scale. This issue has limited the use of graphene for commercial applications. The polar functional groups of humic acid contribute to the hydrophilic nature of the molecule, limiting its miscibility in any alkyl-based solvent. Surfactants containing long alkyl chains can affect the miscibility of the molecule in an organic solvent. Surfactants are often difficult to remove from the system. It is theorized that alkylation of the functional sites of humic acid can affect the hydrophilic nature of the molecule, and effectively enable its dispersion into organic solvents without simultaneous incorporation of surfactants. This dissertation investigated the amidation and esterification of humic acid molecules extracted from leonardite. The resulting change in the modified humic acid dispersibility in organic solvents and its potential usage as a fuel additive were evaluated. Butyl, hexyl, octyl, and decyl amide-modified and ester-modified humic acids were synthesized. These products were characterized to confirm successful chemical reaction through thermogravimetric analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The decyl-modified humic acids remained suspended in kerosene mixtures for longer than 1 week. Other organo-humic acids showed varying degrees of flocculation

Optimized Diazo Scaffold for Protein Esterification

Science.gov (United States)

Mix, Kalie A.

2015-01-01

The O-alkylation of carboxylic acids with diazo compounds provides a means to esterify carboxylic acids in aqueous solution. A Hammett analysis of the reactivity of diazo compounds derived from phenylglycinamide revealed that the p-methylphenylglycinamide scaffold has an especially high reaction rate and ester:alcohol product ratio, and esterifies protein carboxyl groups more efficiently than does any known reagent. PMID:25938936

Role of fatty-acid synthesis in dendritic cell generation and function.

Science.gov (United States)

Rehman, Adeel; Hemmert, Keith C; Ochi, Atsuo; Jamal, Mohsin; Henning, Justin R; Barilla, Rocky; Quesada, Juan P; Zambirinis, Constantinos P; Tang, Kerry; Ego-Osuala, Melvin; Rao, Raghavendra S; Greco, Stephanie; Deutsch, Michael; Narayan, Suchithra; Pachter, H Leon; Graffeo, Christopher S; Acehan, Devrim; Miller, George

2013-05-01

Dendritic cells (DC) are professional APCs that regulate innate and adaptive immunity. The role of fatty-acid synthesis in DC development and function is uncertain. We found that blockade of fatty-acid synthesis markedly decreases dendropoiesis in the liver and in primary and secondary lymphoid organs in mice. Human DC development from PBMC precursors was also diminished by blockade of fatty-acid synthesis. This was associated with higher rates of apoptosis in precursor cells and increased expression of cleaved caspase-3 and BCL-xL and downregulation of cyclin B1. Further, blockade of fatty-acid synthesis decreased DC expression of MHC class II, ICAM-1, B7-1, and B7-2 but increased their production of selected proinflammatory cytokines including IL-12 and MCP-1. Accordingly, inhibition of fatty-acid synthesis enhanced DC capacity to activate allogeneic as well as Ag-restricted CD4(+) and CD8(+) T cells and induce CTL responses. Further, blockade of fatty-acid synthesis increased DC expression of Notch ligands and enhanced their ability to activate NK cell immune phenotype and IFN-γ production. Because endoplasmic reticulum (ER) stress can augment the immunogenic function of APC, we postulated that this may account for the higher DC immunogenicity. We found that inhibition of fatty-acid synthesis resulted in elevated expression of numerous markers of ER stress in humans and mice and was associated with increased MAPK and Akt signaling. Further, lowering ER stress by 4-phenylbutyrate mitigated the enhanced immune stimulation associated with fatty-acid synthesis blockade. Our findings elucidate the role of fatty-acid synthesis in DC development and function and have implications to the design of DC vaccines for immunotherapy.

Direct measurement of the interaction energy between solids and gases--3. Comparison of the calorimetric titration method with the amine titration method for the determination of acid strength distribution of the silica-alumina surface

Energy Technology Data Exchange (ETDEWEB)

Taniguchi, H.; Masuda, T.; Tsutsumi, K.; Takahashi, H.

1978-07-01

Comparison of the calorimetric titration method with the amine titration method for the determination of acid strength distribution of the silica-alumina surface was carried out for a catalyst containing 13% by wt alumina and evacuated at 400/sup 0/C at 0.00001 mm Hg for five hours. The heats of adsorption of ammonia on silica-alumina poisoned with Hammett indicators of 8.2 to 3.3 pK/sub a/ were also measured to obtain the relation between the dissociation constant of the acid (pK/sub a/) and the heat of adsorption. At pK/sub a/ values of -5.6 and +3.3, the differential heats of adsorption were 76.1 and 55.1 kj/mole, respectively. The number of acid sites calculated from the heat vs. adsorbed-amount curve was about twice as large as that determined by amine titration. The discrepancy is discussed.

Spectral and Mechanistic Investigation of Oxidative Decarboxylation of Phenylsulfinylacetic Acid by Cr(VI)

International Nuclear Information System (INIS)

Subramaniam, Perumal; Selvi, Natesan Thamil; Devi, Soundarapandian Sugirtha

2014-01-01

The oxidative decarboxylation of phenylsulfinylacetic acid (PSAA) by Cr(VI) in 20% acetonitrile . 80% water (v/v) medium follows overall second order kinetics, first order each with respect to [PSAA] and [Cr(VI)] at constant [H + ] and ionic strength. The reaction is acid catalysed, the order with respect to [H + ] is unity and the active oxidizing species is found to be HCrO 3 + . The reaction mechanism involves the rate determining nucleophilic attack of sulfur atom of PSAA on chromium of HCrO 3 + forming a sulfonium ion intermediate. The intermediate then undergoes α,β-cleavage leading to the liberation of CO 2 . The product of the reaction is found to be methyl phenyl sulfone. The operation of substituent effect shows that PSAA containing electron-releasing groups in the meta- and para-positions accelerate the reaction rate while electron withdrawing groups retard the rate. An excellent correlation is found to exist between log k 2 and Hammett σ constants with a negative value of reaction constant. The ρ value decreases with increase in temperature evidencing the high reactivity and low selectivity in the case of substituted PSAAs

Interactive effects of ambient acidity and salinity on thyroid function during acidic and post-acidic acclimation of air-breathing fish (Anabas testudineus Bloch).

Science.gov (United States)

Peter, M C Subhash; Rejitha, V

2011-11-01

The interactive effects of ambient acidity and salinity on thyroid function are less understood in fish particularly in air-breathing fish. We, therefore, examined the thyroid function particularly the osmotic and metabolic competences of freshwater (FW) and salinity-adapted (SA; 20 ppt) air-breathing fish (Anabas testudineus) during acidic and post-acidic acclimation, i.e., during the exposure of fish to either acidified water (pH 4.2 and 5.2) for 48 h or clean water for 96 h after pre-exposure. A substantial rise in plasma T(4) occurred after acidic exposure of both FW and SA fish. Similarly, increased plasma T(3) and T(4) were found in FW fish kept for post-acidic acclimation and these suggest an involvement of THs in short-term acidic and post-acidic acclimation. Water acidification produced significant hyperglycaemia and hyperuremia in FW fish but not in SA fish. The SA fish when kept for post-acclimation, however, produced a significant hypouremia. In both FW and SA fish, gill Na(+), K(+)-ATPase activity decreased but kidney Na(+), K(+)-ATPase activity increased upon acidic acclimation. During post-acidic acclimation, gill Na(+), K(+)-ATPase activity of the FW fish showed a rise while decreasing its activity in the SA fish. Similarly, post-acidic acclimation reduced the Na(+), K(+)-ATPase activity of intestine but elevated its activity in the liver of SA fish. A higher tolerance of the SA fish to water acidification was evident in these fish as they showed tight plasma and tissue mineral status due to the ability of this fish to counteract the ion loss. In contrast, FW fish showed more sensitivity to water acidification as they loose more ions in that medium. The positive correlations of plasma THs with many tested metabolic and hydromineral indices of both FW and SA fish and also with water pH further confirm the involvement of THs in acidic and post-acidic acclimation in these fish. We conclude that thyroid function of this fish is more sensitive to

[Effect of high blood levels of bile acid on respiratory functions of New Zealand rabbits].

Science.gov (United States)

Wang, Fei; Zhao, Cong; Tian, Yinghong; Yin, Yanru

2013-08-01

To compare the patterns of respiratory function variations resulting from the classical reflex of blood pressure fall and high blood levels of bile acid, so as to provide evidence for the regulation of respiratory function via bile acids. Seventy New Zealand male Rabbits, under general anesthesia with 20% urethane, were subjected to tracheal intubations and carotid artery cannulations via median incisions of the neck. Using a biological signal acquisition system, the changes in the breathing and blood pressure were observed in response to stimulation of the pneumogastric nerves or to ear vein injections of diluted bile acids or the water solutions of 5 dissociated bile acids. Stimulation of the pneumogastric nerves and injections of diluted bile acids both lowered the blood pressure without significant differences in the total reaction time (T). However, the total respiratory reaction time of bile acids, RT(bile acids), was 9-10 times longer than the total reaction time of blood pressure T(bile acids) (Pacids) were higher than that RR(pneumogastric nerves)resulting from the classical reflex (Pacids), the values of RR(bile acids) were significantly higher than those of RR(bile acids) in RT2(bile acids) interval. UDCA produced no significant influence on blood pressure or respiratory function (Pacid reagents did (Pacids not only act through reflex factors but also have direct effects on respiratory function regulation. Under our experimental conditions, UDCA has no effect on blood pressure or respiratory function, but the other 4 dissociated bile acid reagents can all dose-dependently lower blood pressure and significantly affect respiratory function.

A Functional Tricarboxylic Acid Cycle Operates during Growth of Bordetella pertussis on Amino Acid Mixtures as Sole Carbon Substrates.

Directory of Open Access Journals (Sweden)

Marie Izac

Full Text Available It has been claimed that citrate synthase, aconitase and isocitrate dehydrogenase activities are non-functional in Bordetella pertussis and that this might explain why this bacterium's growth is sometimes associated with accumulation of polyhydroxybutyrate (PHB and/or free fatty acids. However, the sequenced genome includes the entire citric acid pathway genes. Furthermore, these genes were expressed and the corresponding enzyme activities detected at high levels for the pathway when grown on a defined medium imitating the amino acid content of complex media often used for growth of this pathogenic microorganism. In addition, no significant PHB or fatty acids could be detected. Analysis of the carbon balance and stoichiometric flux analysis based on specific rates of amino acid consumption, and estimated biomass requirements coherent with the observed growth rate, clearly indicate that a fully functional tricarboxylic acid cycle operates in contrast to previous reports.

Do uric acid deposits in zooxanthellae function as eye-spots?

Directory of Open Access Journals (Sweden)

Hiroshi Yamashita

2009-07-01

Full Text Available The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100-150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot.

Do uric acid deposits in zooxanthellae function as eye-spots?

Science.gov (United States)

Yamashita, Hiroshi; Kobiyama, Atsushi; Koike, Kazuhiko

2009-07-17

The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium) and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100-150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot.

Acid functionalized, highly dispersed carbonaceous spheres: an effective solid acid for hydrolysis of polysaccharides

International Nuclear Information System (INIS)

Jiang Yijun; Li Xiutao; Cao Quan; Mu Xindong

2011-01-01

Highly dispersed carbonaceous spheres with sulfonic acid groups were successfully prepared from glucose by hydrothermal method. Transmission electron microscopy (TEM) showed the as-synthesized carbonaceous materials were uniform, spherical in shape with an average diameter of about 450 nm. Fourier transform infrared (FT-IR) proved that –SO 3 H, –COOH, OH groups were grafted on the surface of the carbonaceous spheres during the sulfonation. Interestingly, the functionalized carbonaceous spheres exhibited high dispersibility in the polar solvent due to the hydrophilic groups on the surface. The mechanism of the formation for the carbonaceous spheres was also discussed based on the analysis of structure and composition. At last, the functionalized carbonaceous spheres were employed as solid acid to hydrolyze starch and cellulose. By comparison, the as-synthesized catalyst showed considerable high yield of glucose.

Acid functionalized, highly dispersed carbonaceous spheres: an effective solid acid for hydrolysis of polysaccharides

Science.gov (United States)

Jiang, Yijun; Li, Xiutao; Cao, Quan; Mu, Xindong

2011-02-01

Highly dispersed carbonaceous spheres with sulfonic acid groups were successfully prepared from glucose by hydrothermal method. Transmission electron microscopy (TEM) showed the as-synthesized carbonaceous materials were uniform, spherical in shape with an average diameter of about 450 nm. Fourier transform infrared (FT-IR) proved that -SO3H, -COOH, OH groups were grafted on the surface of the carbonaceous spheres during the sulfonation. Interestingly, the functionalized carbonaceous spheres exhibited high dispersibility in the polar solvent due to the hydrophilic groups on the surface. The mechanism of the formation for the carbonaceous spheres was also discussed based on the analysis of structure and composition. At last, the functionalized carbonaceous spheres were employed as solid acid to hydrolyze starch and cellulose. By comparison, the as-synthesized catalyst showed considerable high yield of glucose.

Poly(amino acid) functionalized maghemite and gold nanoparticles

International Nuclear Information System (INIS)

Perego, Davide; Manuel Domínguez-Vera, José; Gálvez, Natividad; Masciocchi, Norberto; Guagliardi, Antonietta

2013-01-01

Bimodal MRI/OI imaging probes are of great interest in nanomedicine. Although many organic polymers have been studied thoroughly for in vivo applications, reports on the use of poly(amino acid)s as coating polymers are scarce. In this paper, poly-(d-glutamic acid, d-lysine) (PGL) has been used for coating maghemite and gold nanoparticles. An advantage of this flexible and biocompatible polymer is that, once anchored to the nanoparticle surface, dangling lysine amino groups are available for the incorporation of new functionalities. As an example, Alexa Fluor derivatives have been attached to PGL-coated maghemite nanoparticles to obtain magnetic/fluorescent materials. These dual-property materials could be used as bimodal MRI/OI probes for in vivo imaging. (paper)

Repeated functional convergent effects of NaV1.7 on acid insensitivity in hibernating mammals.

Science.gov (United States)

Liu, Zhen; Wang, Wei; Zhang, Tong-Zuo; Li, Gong-Hua; He, Kai; Huang, Jing-Fei; Jiang, Xue-Long; Murphy, Robert W; Shi, Peng

2014-02-07

Hibernating mammals need to be insensitive to acid in order to cope with conditions of high CO2; however, the molecular basis of acid tolerance remains largely unknown. The African naked mole-rat (Heterocephalus glaber) and hibernating mammals share similar environments and physiological features. In the naked mole-rat, acid insensitivity has been shown to be conferred by the functional motif of the sodium ion channel NaV1.7. There is now an opportunity to evaluate acid insensitivity in other taxa. In this study, we tested for functional convergence of NaV1.7 in 71 species of mammals, including 22 species that hibernate. Our analyses revealed a functional convergence of amino acid sequences, which occurred at least six times independently in mammals that hibernate. Evolutionary analyses determined that the convergence results from both parallel and divergent evolution of residues in the functional motif. Our findings not only identify the functional molecules responsible for acid insensitivity in hibernating mammals, but also open new avenues to elucidate the molecular underpinnings of acid insensitivity in mammals.

Functionalization of carbon nanotube yarn by acid treatment

Directory of Open Access Journals (Sweden)

H.E. Misak

2014-01-01

Full Text Available Carbon nanotube (CNT yarn was functionalized using sulfuric and nitric acid solutions in 3:1 volumetric ratio. Successful functionalization of CNT yarn with carboxyl and hydroxyl groups (e.g., COOH, COO–, OH, etc. was confirmed by attenuated total reflectance spectroscopy. X-ray diffraction revealed no significant change to the atomic in-plane alignment in the CNTs; however, the coherent length along the diameter was significantly reduced during functionalization. A morphology change of wavy extensions protruding from the surface was observed after the functionalization treatment. The force required to fracture the yarn remained the same after the functionalization process; however, the linear density was increased (310%. The increase in linear density after functionalization reduced the tenacity. However, the resistivity density product of the CNT yarn was reduced significantly (234% after functionalization.

The Antifungal Activity of Functionalized Chitin Nanocrystals in Poly (Lactid Acid Films

Directory of Open Access Journals (Sweden)

Asier M. Salaberria

2017-05-01

Full Text Available As, in the market, poly (lactic acid (PLA is the most used polymer as an alternative to conventional plastics, and as functionalized chitin nanocrystals (CHNC can provide structural and bioactive properties, their combination sounds promising in the preparation of functional nanocomposite films for sustainable packaging. Chitin nanocrystals were successfully modified via acylation using anhydride acetic and dodecanoyl chloride acid to improve their compatibility with the matrix, PLA. The nanocomposite films were prepared by extrusion/compression approach using different concentrations of both sets of functionalized CHNC. This investigation brings forward that both sets of modified CHNC act as functional agents, i.e., they slightly improved the hydrophobic character of the PLA nanocomposite films, and, very importantly, they also enhanced their antifungal activity. Nonetheless, the nanocomposite films prepared with the CHNC modified with dodecanoyl chloride acid presented the best properties.

[Correlation Between Functional Groups and Radical Scavenging Activities of Acidic Polysaccharides from Dendrobium].

Science.gov (United States)

Liao, Ying; Yuan, Wen-yu; Zheng, Wen-ke; Luo, Ao-xue; Fan, Yi-jun

2015-11-01

To compare the radical scavenging activity of five different acidic polysaccharides, and to find the correlation with the functional groups. Alkali extraction method and Stepwise ethanol precipitation method were used to extract and concentrate the five Dendrobium polysaccharides, and to determine the contents of sulfuric acid and uronic acid of each kind of acidic polysaccharides, and the scavenging activity to ABTS+ radical and hydroxyl radical. Functional group structures were examined by FTIR Spectrometer. Five kinds of Dendrobium polysaccharides had different ability of scavenging ABTS+ free radical and hydroxyl free radical. Moreover, the study had shown that five kinds of antioxidant activity of acidic polysaccharides had obvious correlation withuronic acid and sulfuric acid. The antioxidant activity of each sample was positively correlated with the content of uronic acid, and negatively correlated with the content of sulfuric acid. Sulfuric acid can inhibit the antioxidant activity of acidic polysaccharide but uronic acid can enhance the free radical scavenging activity. By analyzing the structure characteristics of five acidic polysaccharides, all samples have similar structures, however, Dendrobium denneanum, Dendrobium devonianum and Dendrobium officinale which had β configuration have higher antioxidant activity than Dendrobium nobile and Dendrobium fimbriatum which had a configuration.

A density functional theory study of magneto-electric Jones birefringence of noble gases, furan homologues, and mono-substituted benzenes

International Nuclear Information System (INIS)

Fahleson, Tobias; Norman, Patrick; Coriani, Sonia; Rizzo, Antonio; Rikken, Geert L. J. A.

2013-01-01

We report on the results of a systematic ab initio study of the Jones birefringence of noble gases, of furan homologues, and of monosubstituted benzenes, in the gas phase, with the aim of analyzing the behavior and the trends within a list of systems of varying size and complexity, and of identifying candidates for a combined experimental/theoretical study of the effect. We resort here to analytic linear and nonlinear response functions in the framework of time-dependent density functional theory. A correlation is made between the observable (the Jones constant) and the atomic radius for noble gases, or the permanent electric dipole and a structure/chemical reactivity descriptor as the para Hammett constant for substituted benzenes

Retinoic acid synthesis and functions in early embryonic development

Directory of Open Access Journals (Sweden)

Kam Richard Kin Ting

2012-03-01

Full Text Available Abstract Retinoic acid (RA is a morphogen derived from retinol (vitamin A that plays important roles in cell growth, differentiation, and organogenesis. The production of RA from retinol requires two consecutive enzymatic reactions catalyzed by different sets of dehydrogenases. The retinol is first oxidized into retinal, which is then oxidized into RA. The RA interacts with retinoic acid receptor (RAR and retinoic acid X receptor (RXR which then regulate the target gene expression. In this review, we have discussed the metabolism of RA and the important components of RA signaling pathway, and highlighted current understanding of the functions of RA during early embryonic development.

Serum neuron-specific enolase, biogenic amino-acids and neurobehavioral function in lead-exposed workers from lead-acid battery manufacturing process.

Science.gov (United States)

Ravibabu, K; Barman, T; Rajmohan, H R

2015-01-01

The interaction between serum neuron-specific enolase (NSE), biogenic amino-acids and neurobehavioral function with blood lead levels in workers exposed to lead form lead-acid battery manufacturing process was not studied. To evaluate serum NSE and biogenic amino-acids (dopamine and serotonin) levels, and neurobehavioral performance among workers exposed to lead from lead-acid storage battery plant, and its relation with blood lead levels (BLLs). In a cross-sectional study, we performed biochemical and neurobehavioral function tests on 146 workers exposed to lead from lead-acid battery manufacturing process. BLLs were assessed by an atomic absorption spectrophotometer. Serum NSE, dopamine and serotonin were measured by ELISA. Neurobehavioral functions were assessed by CDC-recommended tests---simple reaction time (SRT), symbol digit substitution test (SDST), and serial digit learning test (SDLT). There was a significant correlation (r 0.199, pSDLT and SRT had also a significant positive correlation (r 0.238, p<0.01). NSE had a negative correlation (r -0.194, p<0.05) with serotonin level. Multiple linear regression analysis revealed that both SRT and SDST had positive significant associations with BLL. SRT also had a positive significant association with age. Serum NSE cannot be used as a marker for BLL. The only domain of neurobehavioral function tests that is affected by increased BLL in workers of lead-acid battery manufacturing process is that of the "attention and perception" (SDST).

Glucose-Sensitive Hydrogel Optical Fibers Functionalized with Phenylboronic Acid.

Science.gov (United States)

Yetisen, Ali K; Jiang, Nan; Fallahi, Afsoon; Montelongo, Yunuen; Ruiz-Esparza, Guillermo U; Tamayol, Ali; Zhang, Yu Shrike; Mahmood, Iram; Yang, Su-A; Kim, Ki Su; Butt, Haider; Khademhosseini, Ali; Yun, Seok-Hyun

2017-04-01

Hydrogel optical fibers are utilized for continuous glucose sensing in real time. The hydrogel fibers consist of poly(acrylamide-co-poly(ethylene glycol) diacrylate) cores functionalized with phenylboronic acid. The complexation of the phenylboronic acid and cis-diol groups of glucose enables reversible changes of the hydrogel fiber diameter. The analyses of light propagation loss allow for quantitative glucose measurements within the physiological range. © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcriptome mining and in silico structural and functional analysis of ascorbic acid and tartaric acid biosynthesis pathway enzymes in rose-scanted geranium.

Science.gov (United States)

Narnoliya, Lokesh K; Sangwan, Rajender S; Singh, Sudhir P

2018-06-01

Rose-scented geranium (Pelargonium sp.) is widely known as aromatic and medicinal herb, accumulating specialized metabolites of high economic importance, such as essential oils, ascorbic acid, and tartaric acid. Ascorbic acid and tartaric acid are multifunctional metabolites of human value to be used as vital antioxidants and flavor enhancing agents in food products. No information is available related to the structural and functional properties of the enzymes involved in ascorbic acid and tartaric acid biosynthesis in rose-scented geranium. In the present study, transcriptome mining was done to identify full-length genes, followed by their bioinformatic and molecular modeling investigations and understanding of in silico structural and functional properties of these enzymes. Evolutionary conserved domains were identified in the pathway enzymes. In silico physicochemical characterization of the catalytic enzymes revealed isoelectric point (pI), instability index, aliphatic index, and grand average hydropathy (GRAVY) values of the enzymes. Secondary structural prediction revealed abundant proportion of alpha helix and random coil confirmations in the pathway enzymes. Three-dimensional homology models were developed for these enzymes. The predicted structures showed significant structural similarity with their respective templates in root mean square deviation analysis. Ramachandran plot analysis of the modeled enzymes revealed that more than 84% of the amino acid residues were within the favored regions. Further, functionally important residues were identified corresponding to catalytic sites located in the enzymes. To, our best knowledge, this is the first report which provides a foundation on functional annotation and structural determination of ascorbic acid and tartaric acid pathway enzymes in rose-scanted geranium.

Dehydration of D-xylose to furfural using acid-functionalized MWCNTs catalysts

Science.gov (United States)

Termvidchakorn, Chompoopitch; Itthibenchapong, Vorranutch; Songtawee, Siripit; Chamnankid, Busaya; Namuangruk, Supawadee; Faungnawakij, Kajornsak; Charinpanitkul, Tawatchai; Khunchit, Radchadaporn; Hansupaluk, Nanthiya; Sano, Noriaki; Hinode, Hirofumi

2017-09-01

Acid-functionalized multi-wall carbon nanotubes (MWCNTs) catalysts were prepared by a wet chemical sonication with various acid solutions, i.e. H2SO4, H3PO4, HNO3, and HCl. Sulfonic groups and carboxyl groups were detected on MWCNTs with H2SO4 treatment (s-MWCNTs), while only carboxyl groups were presented from other acid treatments. The catalytic dehydration of D-xylose into furfural was evaluated using a batch reactor at 170 °C for 3 h under N2 pressure of 15 bar. The highest furfural selectivity was achieved around 57% by s-MWCNTs catalyst, suggesting a positive role of the sulfonic functionalized groups. The effect of Co species was related to their Lewis acid property resulting in the enhancement of xylose conversion with low selectivity to furfural product. Invited talk at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

Tuning the acid/base properties of nanocarbons by functionalization via amination.

Science.gov (United States)

Arrigo, Rosa; Hävecker, Michael; Wrabetz, Sabine; Blume, Raoul; Lerch, Martin; McGregor, James; Parrott, Edward P J; Zeitler, J Axel; Gladden, Lynn F; Knop-Gericke, Axel; Schlögl, Robert; Su, Dang Sheng

2010-07-21

The surface chemical properties and the electronic properties of vapor grown carbon nanofibers (VGCNFs) have been modified by treatment of the oxidized CNFs with NH(3). The effect of treatment temperature on the types of nitrogen functionalities introduced was evaluated by synchrotron based X-ray photoelectron spectroscopy (XPS), while the impact of the preparation methods on the surface acid-base properties was investigated by potentiometric titration, microcalorimetry, and zeta potential measurements. The impact of the N-functionalization on the electronic properties was measured by THz-Time Domain spectroscopy. The samples functionalized via amination are characterized by the coexistence of acidic and basic O and N sites. The population of O and N species is temperature dependent. In particular, at 873 K nitrogen is stabilized in substitutional positions within the graphitic structure, as heterocyclic-like moieties. The surface presents heterogeneously distributed and energetically different basic sites. A small amount of strong basic sites gives rise to a differential heat of CO(2) adsorption of 150 kJ mol(-1). However, when functionalization is carried out at 473 K, nitrogen moieties with basic character are introduced and the maximum heat of adsorption is significantly lower, at approximately 90 kJ mol(-1). In the latter sample, energetically different basic sites coexist with acidic oxygen groups introduced during the oxidative step. Under these conditions, a bifunctional acidic and basic surface is obtained with high hydrophilic character. N-functionalization carried out at higher temperature changes the electronic properties of the CNFs as evaluated by THz-TDS. The functionalization procedure presented in this work allows high versatility and flexibility in tailoring the surface chemistry of nanocarbon material to specific needs. This work shows the potential of the N-containing nanocarbon materials obtained via amination in catalysis as well as electronic

Serum Neuron-Specific Enolase, Biogenic Amino-Acids and Neurobehavioral Function in Lead-Exposed Workers from Lead-Acid Battery Manufacturing Process

Directory of Open Access Journals (Sweden)

K Ravibabu

2015-01-01

Full Text Available Background: The interaction between serum neuron-specific enolase (NSE, biogenic amino-acids and neurobehavioral function with blood lead levels in workers exposed to lead form lead-acid battery manufacturing process was not studied. Objective: To evaluate serum NSE and biogenic amino-acids (dopamine and serotonin levels, and neurobehavioral performance among workers exposed to lead from lead-acid storage battery plant, and its relation with blood lead levels (BLLs. Methods: In a cross-sectional study, we performed biochemical and neurobehavioral function tests on 146 workers exposed to lead from lead-acid battery manufacturing process. BLLs were assessed by an atomic absorption spectrophotometer. Serum NSE, dopamine and serotonin were measured by ELISA. Neurobehavioral functions were assessed by CDC-recommended tests—simple reaction time (SRT, symbol digit substitution test (SDST, and serial digit learning test (SDLT. Results: There was a significant correlation (r 0.199, p<0.05 between SDST and BLL. SDLT and SRT had also a significant positive correlation (r 0.238, p<0.01. NSE had a negative correlation (r –0.194, p<0.05 with serotonin level. Multiple linear regression analysis revealed that both SRT and SDST had positive significant associations with BLL. SRT also had a positive significant association with age. Conclusion: Serum NSE cannot be used as a marker for BLL. The only domain of neurobehavioral function tests that is affected by increased BLL in workers of lead-acid battery manufacturing process is that of the “attention and perception” (SDST.

Bronsted acid-functionalized choline chloride-butane sultone for the ...

Indian Academy of Sciences (India)

M P PADMA PRIYA

2018-03-21

Mar 21, 2018 ... Choline chloride and 1,4-butane sultone were combined to obtain a sulphonic acid-functionalized ..... Knifton J F and Sanderson J R 1990 Method for produc- ... alkenes via the Knoevenagel condensation Tetrahedron. Lett.

Improved mitochondrial function with diet-induced increase in either docosahexaenoic acid or arachidonic acid in membrane phospholipids.

Directory of Open Access Journals (Sweden)

Ramzi J Khairallah

Full Text Available Mitochondria can depolarize and trigger cell death through the opening of the mitochondrial permeability transition pore (MPTP. We recently showed that an increase in the long chain n3 polyunsaturated fatty acids (PUFA docosahexaenoic acid (DHA; 22:6n3 and depletion of the n6 PUFA arachidonic acid (ARA; 20:4n6 in mitochondrial membranes is associated with a greater Ca(2+ load required to induce MPTP opening. Here we manipulated mitochondrial phospholipid composition by supplementing the diet with DHA, ARA or combined DHA+ARA in rats for 10 weeks. There were no effects on cardiac function, or respiration of isolated mitochondria. Analysis of mitochondrial phospholipids showed DHA supplementation increased DHA and displaced ARA in mitochondrial membranes, while supplementation with ARA or DHA+ARA increased ARA and depleted linoleic acid (18:2n6. Phospholipid analysis revealed a similar pattern, particularly in cardiolipin. Tetralinoleoyl cardiolipin was depleted by 80% with ARA or DHA+ARA supplementation, with linoleic acid side chains replaced by ARA. Both the DHA and ARA groups had delayed Ca(2+-induced MPTP opening, but the DHA+ARA group was similar to the control diet. In conclusion, alterations in mitochondria membrane phospholipid fatty acid composition caused by dietary DHA or ARA was associated with a greater cumulative Ca(2+ load required to induced MPTP opening. Further, high levels of tetralinoleoyl cardiolipin were not essential for normal mitochondrial function if replaced with very-long chain n3 or n6 PUFAs.

Identification of novel functional inhibitors of acid sphingomyelinase.

Directory of Open Access Journals (Sweden)

Johannes Kornhuber

Full Text Available We describe a hitherto unknown feature for 27 small drug-like molecules, namely functional inhibition of acid sphingomyelinase (ASM. These entities named FIASMAs (Functional Inhibitors of Acid SphingoMyelinAse, therefore, can be potentially used to treat diseases associated with enhanced activity of ASM, such as Alzheimer's disease, major depression, radiation- and chemotherapy-induced apoptosis and endotoxic shock syndrome. Residual activity of ASM measured in the presence of 10 µM drug concentration shows a bimodal distribution; thus the tested drugs can be classified into two groups with lower and higher inhibitory activity. All FIASMAs share distinct physicochemical properties in showing lipophilic and weakly basic properties. Hierarchical clustering of Tanimoto coefficients revealed that FIASMAs occur among drugs of various chemical scaffolds. Moreover, FIASMAs more frequently violate Lipinski's Rule-of-Five than compounds without effect on ASM. Inhibition of ASM appears to be associated with good permeability across the blood-brain barrier. In the present investigation, we developed a novel structure-property-activity relationship by using a random forest-based binary classification learner. Virtual screening revealed that only six out of 768 (0.78% compounds of natural products functionally inhibit ASM, whereas this inhibitory activity occurs in 135 out of 2028 (6.66% drugs licensed for medical use in humans.

Using Caenorhabditis elegans to Uncover Conserved Functions of Omega-3 and Omega-6 Fatty Acids

Science.gov (United States)

Watts, Jennifer L.

2016-01-01

The nematode Caenorhabditis elegans is a powerful model organism to study functions of polyunsaturated fatty acids. The ability to alter fatty acid composition with genetic manipulation and dietary supplementation permits the dissection of the roles of omega-3 and omega-6 fatty acids in many biological process including reproduction, aging and neurobiology. Studies in C. elegans to date have mostly identified overlapping functions of 20-carbon omega-6 and omega-3 fatty acids in reproduction and in neurons, however, specific roles for either omega-3 or omega-6 fatty acids are beginning to emerge. Recent findings with importance to human health include the identification of a conserved Cox-independent prostaglandin synthesis pathway, critical functions for cytochrome P450 derivatives of polyunsaturated fatty acids, the requirements for omega-6 and omega-3 fatty acids in sensory neurons, and the importance of fatty acid desaturation for long lifespan. Furthermore, the ability of C. elegans to interconvert omega-6 to omega-3 fatty acids using the FAT-1 omega-3 desaturase has been exploited in mammalian studies and biotechnology approaches to generate mammals capable of exogenous generation of omega-3 fatty acids. PMID:26848697

N-3 fatty acids and membrane microdomains: from model membranes to lymphocyte function.

Science.gov (United States)

Shaikh, Saame Raza; Teague, Heather

2012-12-01

This article summarizes the author's research on fish oil derived n-3 fatty acids, plasma membrane organization and B cell function. We first cover basic model membrane studies that investigated how docosahexaenoic acid (DHA) targeted the organization of sphingolipid-cholesterol enriched lipid microdomains. A key finding here was that DHA had a relatively poor affinity for cholesterol. This work led to a model that predicted DHA acyl chains in cells would manipulate lipid-protein microdomain organization and thereby function. We then review how the predictions of the model were tested with B cells in vitro followed by experiments using mice fed fish oil. These studies reveal a highly complex picture on how n-3 fatty acids target lipid-protein organization and B cell function. Key findings are as follows: (1) n-3 fatty acids target not just the plasma membrane but also endomembrane organization; (2) DHA, but not eicosapentaenoic acid (EPA), disrupts microdomain spatial distribution (i.e. clustering), (3) DHA alters protein lateral organization and (4) changes in membrane organization are accompanied by functional effects on both innate and adaptive B cell function. Altogether, the research over the past 10 years has led to an evolution of the original model on how DHA reorganizes membrane microdomains. The work raises the intriguing possibility of testing the model at the human level to target health and disease. Copyright © 2012 Elsevier Ltd. All rights reserved.

Function modification of SR-PSOX by point mutations of basic amino acids

Directory of Open Access Journals (Sweden)

Chen Chunxia

2011-04-01

Full Text Available Abstract Background Atherosclerosis (AS is a common cardiovascular disease. Transformation of macrophages to form foam cells by internalizing modified low density-lipoprotein (LDL via scavenger receptor (SR is a key pathogenic process in the onset of AS. It has been demonstrated that SR-PSOX functions as either a scavenger receptor for uptake of atherogenic lipoproteins and bacteria or a membrane-anchored chemokine for adhesion of macrophages and T-cells to the endothelium. Therefore, SR-PSOX plays an important role in the development of AS. In this study the key basic amino acids in the chemokine domain of SR-PSOX have been identified for its functions. Results A cell model to study the functions of SR-PSOX was successfully established. Based on the cell model, a series of mutants of human SR-PSOX were constructed by replacing the single basic amino acid residue in the non-conservative region of the chemokine domain (arginine 62, arginine 78, histidine 80, arginine 82, histidine 85, lysine 105, lysine 119, histidine 123 with alanine (designated as R62A, R78A, H80A, R82A, H85A, K105A, K119A and H123A, respectively. Functional studies showed that the mutants with H80A, H85A, and K105A significantly increased the activities of oxLDL uptake and bacterial phagocytosis compared with the wild-type SR-PSOX. In addition, we have also found that mutagenesis of either of those amino acids strongly reduced the adhesive activity of SR-PSOX by using a highly non-overlapping set of basic amino acid residues. Conclusion Our study demonstrates that basic amino acid residues in the non-conservative region of the chemokine domain of SR-PSOX are critical for its functions. Mutation of H80, H85, and K105 is responsible for increasing SR-PSOX binding with oxLDL and bacteria. All the basic amino acids in this region are important in the cells adhesion via SR-PSOX. These findings suggest that mutagenesis of the basic amino acids in the chemokine domain of SR-PSOX may

Acid monomer analysis in waterborne polymer systems by targeted labeling of carboxylic acid functionality, followed by pyrolysis - gas chromatography.

Science.gov (United States)

Brooijmans, T; Okhuijsen, R; Oerlemans, I; Schoenmakers, P J; Peters, R

2018-05-14

Pyrolysis - gas chromatography - (PyGC) is a common method to analyse the composition of natural and synthetic resins. The analysis of acid functionality in, for example, waterborne polyacrylates and polyurethanes polymers has proven to be difficult due to solubility issues, inter- and intramolecular interaction effects, lack of detectability in chromatographic analysis, and lack of thermal stability. Conventional analytical techniques, such as PyGC, cannot be used for the direct detection and identification of acidic monomers, due to thermal rearrangements that take place during pyrolysis. To circumvent this, the carboxylic acid groups are protected prior to thermal treatment by reaction with 2-bromoacetophenone. Reaction conditions are investigated and optimised wrt. conversion measurements. The aproach is applied to waterborne polyacryalates and the results are discussed. This approach enables identification and (semi)quantitative analysis of different acid functionalities in waterborne polymers by PyGC. Copyright © 2018 Elsevier B.V. All rights reserved.

High γ-aminobutyric acid production from lactic acid bacteria: Emphasis on Lactobacillus brevis as a functional dairy starter.

Science.gov (United States)

Wu, Qinglong; Shah, Nagendra P

2017-11-22

γ-Aminobutyric acid (GABA) and GABA-rich foods have shown anti-hypertensive and anti-depressant activities as the major functions in humans and animals. Hence, high GABA-producing lactic acid bacteria (LAB) could be used as functional starters for manufacturing novel fermented dairy foods. Glutamic acid decarboxylases (GADs) from LAB are highly conserved at the species level based on the phylogenetic tree of GADs from LAB. Moreover, two functionally distinct GADs and one intact gad operon were observed in all the completely sequenced Lactobacillus brevis strains suggesting its common capability to synthesize GABA. Difficulties and strategies for the manufacture of GABA-rich fermented dairy foods have been discussed and proposed, respectively. In addition, a genetic survey on the sequenced LAB strains demonstrated the absence of cell envelope proteinases in the majority of LAB including Lb. brevis, which diminishes their cell viabilities in milk environments due to their non-proteolytic nature. Thus, several strategies have been proposed to overcome the non-proteolytic nature of Lb. brevis in order to produce GABA-rich dairy foods.

Functionalization of Fatty Acid Vesicles through Newly Synthesized Bolaamphiphile-DNA Conjugates

DEFF Research Database (Denmark)

Wamberg, M. C.; Wieczorek, R.; Brier, S. B.

2014-01-01

The surface functionalization of fatty acid vesicles will allow their use as nanoreactors for complex chemistry. In this report, the tethering of several DNA conjugates to decanoic acid vesicles for molecular recognition and synthetic purposes was explored. Due to the highly dynamic nature......), and consists of a single hydrocarbon chain of 20 carbons having on one end a triazole group linked to the S'-phosphate of the nucleic acid and on the other side a hydroxyl-group. Its insertion was so effective that a fluorescent label on the DNA complementary to the conjugate could be used to visualize fatty...... acid structures....

Damage and recovery of skin barrier function after glycolic acid chemical peeling and crystal microdermabrasion.

Science.gov (United States)

Song, Ji Youn; Kang, Hyun A; Kim, Mi-Yeon; Park, Young Min; Kim, Hyung Ok

2004-03-01

Superficial chemical peeling and microdermabrasion have become increasingly popular methods for producing facial rejuvenation. However, there are few studies reporting the skin barrier function changes after these procedures. To evaluate objectively the degree of damage visually and the time needed for the skin barrier function to recover after glycolic acid peeling and aluminum oxide crystal microdermabrasion using noninvasive bioengineering methods. Superficial chemical peeling using 30%, 50%, and 70% glycolic acid and aluminum oxide crystal microdermabrasion were used on the volar forearm of 13 healthy women. The skin response was measured by a visual observation and using an evaporimeter, corneometer, and colorimeter before and after peeling at set time intervals. Both glycolic acid peeling and aluminum oxide crystal microdermabrasion induced significant damage to the skin barrier function immediately after the procedure, and the degree of damage was less severe after the aluminum oxide crystal microdermabrasion compared with glycolic acid peeling. The damaged skin barrier function had recovered within 24 hours after both procedures. The degree of erythema induction was less severe after the aluminum oxide crystal microdermabrasion compared with the glycolic acid peeling procedure. The degree of erythema induced after the glycolic acid peeling procedure was not proportional to the peeling solution concentration used. The erythema subsided within 1 day after the aluminum oxide crystal microdermabrasion procedure and within 4 days after the glycolic acid peeling procedure. These results suggest that the skin barrier function is damaged after the glycolic acid peeling and aluminum oxide crystal microdermabrasion procedure but recovers within 1 to 4 days. Therefore, repeating the superficial peeling procedure at 2-week intervals will allow sufficient time for the damaged skin to recover its barrier function.

Optimizing scoring function of protein-nucleic acid interactions with both affinity and specificity.

Directory of Open Access Journals (Sweden)

Zhiqiang Yan

Full Text Available Protein-nucleic acid (protein-DNA and protein-RNA recognition is fundamental to the regulation of gene expression. Determination of the structures of the protein-nucleic acid recognition and insight into their interactions at molecular level are vital to understanding the regulation function. Recently, quantitative computational approach has been becoming an alternative of experimental technique for predicting the structures and interactions of biomolecular recognition. However, the progress of protein-nucleic acid structure prediction, especially protein-RNA, is far behind that of the protein-ligand and protein-protein structure predictions due to the lack of reliable and accurate scoring function for quantifying the protein-nucleic acid interactions. In this work, we developed an accurate scoring function (named as SPA-PN, SPecificity and Affinity of the Protein-Nucleic acid interactions for protein-nucleic acid interactions by incorporating both the specificity and affinity into the optimization strategy. Specificity and affinity are two requirements of highly efficient and specific biomolecular recognition. Previous quantitative descriptions of the biomolecular interactions considered the affinity, but often ignored the specificity owing to the challenge of specificity quantification. We applied our concept of intrinsic specificity to connect the conventional specificity, which circumvents the challenge of specificity quantification. In addition to the affinity optimization, we incorporated the quantified intrinsic specificity into the optimization strategy of SPA-PN. The testing results and comparisons with other scoring functions validated that SPA-PN performs well on both the prediction of binding affinity and identification of native conformation. In terms of its performance, SPA-PN can be widely used to predict the protein-nucleic acid structures and quantify their interactions.

Humic acids: Structural properties and multiple functionalities for novel technological developments.

Science.gov (United States)

de Melo, Bruna Alice Gomes; Motta, Fernanda Lopes; Santana, Maria Helena Andrade

2016-05-01

Humic acids (HAs) are macromolecules that comprise humic substances (HS), which are organic matter distributed in terrestrial soil, natural water, and sediment. HAs differ from the other HS fractions (fulvic acid and humins) in that they are soluble in alkaline media, partially soluble in water, and insoluble in acidic media. Due to their amphiphilic character, HAs form micelle-like structures in neutral to acidic conditions, which are useful in agriculture, pollution remediation, medicine and pharmaceuticals. HAs have undefined compositions that vary according to the origin, process of obtainment, and functional groups present in their structures, such as quinones, phenols, and carboxylic acids. Quinones are responsible for the formation of reactive oxygen species (ROS) in HAs, which are useful for wound healing and have fungicidal/bactericidal properties. Phenols and carboxylic acids deprotonate in neutral and alkaline media and are responsible for various other functions, such as the antioxidant and anti-inflammatory properties of HAs. In particular, the presence of phenolic groups in HAs provides antioxidant properties due to their free radical scavenging capacity. This paper describes the main multifunctionalities of HAs associated with their structures and properties, focusing on human health applications, and we note perspectives that may lead to novel technological developments. To the best of our knowledge, this is the first review to address this topic from this approach. Copyright © 2015 Elsevier B.V. All rights reserved.

Plant-based Paste Fermented by Lactic Acid Bacteria and Yeast: Functional Analysis and Possibility of Application to Functional Foods

Directory of Open Access Journals (Sweden)

Shinsuke Kuwaki

2012-01-01

Full Text Available A plant-based paste fermented by lactic acid bacteria and yeast (fermented paste was made from various plant materials. The paste was made of fermented food by applying traditional food-preservation techniques, that is, fermentation and sugaring. The fermented paste contained major nutrients (carbohydrates, proteins, and lipids, 18 kinds of amino acids, and vitamins (vitamin A, B 1 B 2 , B 6 , B 12 , E, K, niacin, biotin, pantothenic acid, and folic acid. It contained five kinds of organic acids, and a large amount of dietary fiber and plant phytochemicals. Sucrose from brown sugar, used as a material, was completely resolved into glucose and fructose. Some physiological functions of the fermented paste were examined in vitro. It was demonstrated that the paste possessed antioxidant, antihypertensive, antibacterial, anti-inflammatory, anti-allergy and anti-tyrosinase activities in vitro. It was thought that the fermented paste would be a helpful functional food with various nutrients to help prevent lifestyle diseases.

Serum Neuron-Specific Enolase, Biogenic Amino-Acids and Neurobehavioral Function in Lead-Exposed Workers from Lead-Acid Battery Manufacturing Process

OpenAIRE

K Ravibabu; T Barman; HR Rajmohan

2015-01-01

Background: The interaction between serum neuron-specific enolase (NSE), biogenic amino-acids and neurobehavioral function with blood lead levels in workers exposed to lead form lead-acid battery manufacturing process was not studied. Objective: To evaluate serum NSE and biogenic amino-acids (dopamine and serotonin) levels, and neurobehavioral performance among workers exposed to lead from lead-acid storage battery plant, and its relation with blood lead levels (BLLs). Methods: In a c...

Development of Manufacturing Method of Highly Functional Material Gallic acid-CLA Ester Using Irradiation

International Nuclear Information System (INIS)

Cho, C. H.; Byun, M. W.; Jeong, I. Y.; Kim, D. H.

2006-01-01

Increasing interest and current trends for natural materials with various health beneficial functions by radiation (RT)-biotechnology (BT) fusion by developed countries. However, the information and development of new functional materials using the RT-BT fusion technology is still limited. The target material developed and manufactured by RT-BT fusion technology may have a multi-functional effect on human health and it can be applied for pharmaceutical materials as well as functional food ingredient. The market of functional new materials has been grown dramatically and a multi-functional material manufactured by RT-BT fusion technology may have a great economic impact for both the domestic and overseas market. Development of GA-CLA ester by chemical synthetic method. Transformation of linoleic acid to conjugated linoleic acid by irradiation. Identification and confirmation of the biological functions including antioxidative, cancer cell proliferation inhibition, anti-microbial, enhancement of immune response and lipid metabolism of GA-CLA ester. Increase industrial applicability of the new materials. Development of GA-CLA ester by chemical synthetic method(2 patents submitted). Development of the optimum methodology of GA-CLA and its derivative, octadeca-9,12-dienyl-3,4,5-trihydroxy benzoate). Identification and confirmation of biological activities of GA-CLA. Extramural funding from the Ministry of Commerce, Industry, and Energy subjected by gallic acid-fatty acid derivatives (205,000,000 Won). Provides the basic data for successful project 'Development of cosmeceutical and cosmetics using gallic acid fatty acid derivatives' funded by Ministry of Commerce, Industry, and Energy and collaboration with the Technology-invested venture company, SunBiotech, Co. and problem-solving for industrial application. Complete the patent procedure and publish the results to international or domestic peer-reviewed journals

Role of folic acid in nitric oxide bioavailability and vascular endothelial function.

Science.gov (United States)

Stanhewicz, Anna E; Kenney, W Larry

2017-01-01

Folic acid is a member of the B-vitamin family and is essential for amino acid metabolism. Adequate intake of folic acid is vital for metabolism, cellular homeostasis, and DNA synthesis. Since the initial discovery of folic acid in the 1940s, folate deficiency has been implicated in numerous disease states, primarily those associated with neural tube defects in utero and neurological degeneration later in life. However, in the past decade, epidemiological studies have identified an inverse relation between both folic acid intake and blood folate concentration and cardiovascular health. This association inspired a number of clinical studies that suggested that folic acid supplementation could reverse endothelial dysfunction in patients with cardiovascular disease (CVD). Recently, in vitro and in vivo studies have begun to elucidate the mechanism(s) through which folic acid improves vascular endothelial function. These studies, which are the focus of this review, suggest that folic acid and its active metabolite 5-methyl tetrahydrofolate improve nitric oxide (NO) bioavailability by increasing endothelial NO synthase coupling and NO production as well as by directly scavenging superoxide radicals. By improving NO bioavailability, folic acid may protect or improve endothelial function, thereby preventing or reversing the progression of CVD in those with overt disease or elevated CVD risk. © The Author(s) 2016. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Improvement of CNT dispersion in HDPE by acid and octadecylamine functionalizations

International Nuclear Information System (INIS)

Menezes, Beatriz Rossi Canuto de; Ferreira, Filipe Vargas; Franceschi, Wesley; Brito, Felipe Sales; Nunes, Evelyn Alves; Rodrigues, Karla Faquine; Cividanes, Luciana de Simone; Thim, Gilmar Patrocínio; Rosa, Cintia

2016-01-01

Full text: Since their discovery in 1991, carbon nanotubes (CNTs) have attracted great attention due to their extraordinary structure and exceptional mechanical properties that make them a suitable candidate for polymer-based nanocomposites reinforcement [1]. However, CNTs full potential can only be achieved with a proper dispersion in the matrix, that depends of Van der Waals interactions among CNTs due to the large surface area and the small size. These interactions decrease the CNT dispersion due to the formation of agglomerates. In order to overcome this limitation, surface functionalization with acid and alkyl groups has been used to increase the CNTs dispersion and compatibility with polymer matrix [2]. Therefore, the focus of the present work is to improve the dispersion of CNTs in high density polyethylene (HDPE) matrix through their functionalization with acid (H 2 SO 4 +HNO 3 ) and octadecylamine (ODA:CH 3 (CH 2 ) 17 NH 2 ). The CNT/HDPE nanocomposites (0.8%wt of CNTs) were prepared by mechanical agitation of the melted mixture of CNTs and HDPE and subsequent compression molding. Three nanocomposites were prepared: (1) HDPE + pristine CNTs, (2) HDPE + acid functionalized CNTs, and (3) HDPE + ODA functionalized CNTs. In order to confirm the surface treatment, CNTs was characterized by FT-IR, XPS, Raman, and TEM. The improvement in CNTs dispersion and compatibility with HDPE was verified by tensile test, microhardness, SEM-FEG. The results showed an improvement in the CNTs dispersion for HDPE with acid and ODA functionalized CNTs. The Young's modulus and Vickers microhardness increased significantly for HDPE with treated CNTs when compared with pristine CNTs. References: [1] S Iijima, Nature 354, 56-58 (1991). [2] R Ansari, S Ajori, S Rouhi, Appl Surf Sci 332, 640-647 (2015). (author)

Microbial communities, processes and functions in acid mine drainage ecosystems.

Science.gov (United States)

Chen, Lin-xing; Huang, Li-nan; Méndez-García, Celia; Kuang, Jia-liang; Hua, Zheng-shuang; Liu, Jun; Shu, Wen-sheng

2016-04-01

Acid mine drainage (AMD) is generated from the oxidative dissolution of metal sulfides when water and oxygen are available largely due to human mining activities. This process can be accelerated by indigenous microorganisms. In the last several decades, culture-dependent researches have uncovered and validated the roles of AMD microorganisms in metal sulfides oxidation and acid generation processes, and culture-independent studies have largely revealed the diversity and metabolic potentials and activities of AMD communities, leading towards a full understanding of the microbial diversity, functions and interactions in AMD ecosystems. This review describes the diversity of microorganisms and their functions in AMD ecosystems, and discusses their biotechnological applications in biomining and AMD bioremediation according to their capabilities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Folic acid: a marker of endothelial function in type 2 diabetes?

Directory of Open Access Journals (Sweden)

Arduino A Mangoni

2005-04-01

Full Text Available Arduino A Mangoni1, Roy A Sherwood2, Belinda Asonganyi2, Emma L Ouldred3, Stephen Thomas4, Stephen HD Jackson31Department of Clinical Pharmacology, Centre for Neuroscience, School of Medicine, Flinders University, Adelaide, SA, Australia; 2Clinical Biochemistry, King’s College Hospital, London, UK; 3Department of Health Care of the Elderly, Guy’s, King’s, and St Thomas’ School of Medicine, King’s College, London, UK; 4Department of Diabetic Medicine, King’s College Hospital, London, UKObjectives: Endothelial dysfunction is a common feature of type 2 diabetes. Recent studies suggest that the B-vitamin folic acid exerts direct beneficial effects on endothelial function, beyond the well known homocysteine lowering effects. Therefore, folic acid might represent a novel “biomarker” of endothelial function. We sought to determine whether plasma levels of folic acid determine endothelial-dependent vasodilation in patients with type 2 diabetes.Methods: Forearm arterial blood flow (FABF was measured at baseline and during intrabrachial infusion of the endothelial-dependent vasodilator acetylcholine (15 µg/min and the endothelial-independent vasodilator sodium nitroprusside (2 µg/min in 26 type 2 diabetic patients (age 56.5 ± 0.9 years, means ± SEM with no history of cardiovascular disease.Results: FABF ratio (ie, the ratio between the infused and control forearm FABF significantly increased during acetylcholine (1.10 ± 0.04 vs 1.52 ± 0.07, p < 0.001 and sodium nitroprusside (1.12 ± 0.11 vs 1.62 ± 0.06, p < 0.001 infusions. After correcting for age, gender, diabetes duration, smoking, hypertension, body mass index, microalbuminuria, glycated hemoglobin, low-density lipoprotein cholesterol, and homocysteine, multiple regression analysis showed that plasma folic acid concentration was the only independent determinant (p = 0.037, R2 = 0.22 of acetylcholine-mediated, but not sodium nitroprusside-mediated, vasodilatation

Organosulfonic acid-functionalized mesoporous composites based on natural rubber and hexagonal mesoporous silica

Energy Technology Data Exchange (ETDEWEB)

Nuntang, Sakdinun; Poompradub, Sirilux [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Butnark, Suchada [PTT Research and Technology Institute, PTT Public Company Limited, Wangnoi, Ayutthaya 13170 (Thailand); Yokoi, Toshiyuki; Tatsumi, Takashi [Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ngamcharussrivichai, Chawalit, E-mail: Chawalit.Ng@Chula.ac.th [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand)

2014-10-15

This study is the first report on synthesis, characterization and catalytic application of propylsulfonic acid-functionalized mesoporous composites based on natural rubber (NR) and hexagonal mesoporous silica (HMS). In comparison with propylsulfonic acid-functionalized HMS (HMS-SO{sub 3}H), a series of NR/HMS-SO{sub 3}H composites were prepared via an in situ sol–gel process using tetrahydrofuran as the synthesis media. Tetraethylorthosilicate as the silica source, was simultaneously condensed with 3-mercaptopropyltrimethoxysilane in a solution of NR followed by oxidation with hydrogen peroxide to achieve the mesoporous composites containing propylsulfonic acid groups. Fourier-transform infrared spectroscopy and {sup 29}Si MAS nuclear magnetic resonance spectroscopy results verified that the silica surfaces of the NR/HMS-SO{sub 3}H composites were functionalized with propylsulfonic acid groups and covered with NR molecules. After the incorporation of NR and organo-functional group into HMS, the hexagonal mesostructure remained intact concomitantly with an increased framework wall thickness and unit cell size, as evidenced by the X-ray powder diffraction analysis. Scanning electron microscopy analysis indicated a high interparticle porosity of NR/HMS-SO{sub 3}H composites. The textural properties of NR/HMS-SO{sub 3}H were affected by the amount of MPTMS loading to a smaller extent than that of HMS-SO{sub 3}H. NR/HMS-SO{sub 3}H exhibited higher hydrophobicity than HMS-SO{sub 3}H, as revealed by H{sub 2}O adsorption–desorption measurements. Moreover, the NR/HMS-SO{sub 3}H catalysts possessed a superior specific activity to HMS-SO{sub 3}H in the esterification of lauric acid with ethanol, resulting in a higher conversion level. - Highlights: • Acidic NR/HMS-SO{sub 3}H composites were prepared by in situ sol–gel process. • Propylsulfonic acid was functionalized onto HMS surface by direct co-condensation. • NR/HMS-SO{sub 3}H exhibited a hexagonal

New insights into sulfur amino acids function in gut health and disease

Science.gov (United States)

The gastrointestinal tract (GIT) is a metabolically significant site of sulfur amino acids (SAAs) metabolism in the body. Aside from their role in protein synthesis, methionine and cysteine are involved in many biological functions and diseases. Methionine (MET) is an indispensable amino acid and is...

Branched-chain amino acids alter neurobehavioral function in rats

Science.gov (United States)

Coppola, Anna; Wenner, Brett R.; Ilkayeva, Olga; Stevens, Robert D.; Maggioni, Mauro; Slotkin, Theodore A.; Levin, Edward D.

2013-01-01

Recently, we have described a strong association of branched-chain amino acids (BCAA) and aromatic amino acids (AAA) with obesity and insulin resistance. In the current study, we have investigated the potential impact of BCAA on behavioral functions. We demonstrate that supplementation of either a high-sucrose or a high-fat diet with BCAA induces anxiety-like behavior in rats compared with control groups fed on unsupplemented diets. These behavioral changes are associated with a significant decrease in the concentration of tryptophan (Trp) in brain tissues and a consequent decrease in serotonin but no difference in indices of serotonin synaptic function. The anxiety-like behaviors and decreased levels of Trp in the brain of BCAA-fed rats were reversed by supplementation of Trp in the drinking water but not by administration of fluoxetine, a selective serotonin reuptake inhibitor, suggesting that the behavioral changes are independent of the serotonergic pathway of Trp metabolism. Instead, BCAA supplementation lowers the brain levels of another Trp-derived metabolite, kynurenic acid, and these levels are normalized by Trp supplementation. We conclude that supplementation of high-energy diets with BCAA causes neurobehavioral impairment. Since BCAA are elevated spontaneously in human obesity, our studies suggest a potential mechanism for explaining the strong association of obesity and mood disorders. PMID:23249694

Sulphamic acid-functionalized magnetic Fe3O4 nanoparticles as ...

Indian Academy of Sciences (India)

as recyclable catalyst for synthesis of imidazoles under microwave irradiation ... functionalized magnetic Fe3O4 nanoparticles (SA–MNPs) as a novel solid acid catalyst under solvent-free classical heating ..... green chemistry approach.

Preparation of N, N, N-trimethyl chitosan-functionalized retinoic acid ...

African Journals Online (AJOL)

encapsulated solid lipid nanoparticles for the effective treatment of glioma. Methods: Retinoic acid-loaded solid lipid nanoparticles (R-SLNs) were prepared using homogenization followed by sonication. R-SLN surfaces were functionalized electrostatically ...

Enzymatic Synthesis of Amino Acids Endcapped Polycaprolactone: A Green Route Towards Functional Polyesters.

Science.gov (United States)

Duchiron, Stéphane W; Pollet, Eric; Givry, Sébastien; Avérous, Luc

2018-01-30

ε-caprolactone (CL) has been enzymatically polymerized using α-amino acids based on sulfur (methionine and cysteine) as (co-)initiators and immobilized lipase B of Candida antarctica (CALB) as biocatalyst. In-depth characterizations allowed determining the corresponding involved mechanisms and the polymers thermal properties. Two synthetic strategies were tested, a first one with direct polymerization of CL with the native amino acids and a second one involving the use of an amino acid with protected functional groups. The first route showed that mainly polycaprolactone (PCL) homopolymer could be obtained and highlighted the lack of reactivity of the unmodified amino acids due to poor solubility and affinity with the lipase active site. The second strategy based on protected cysteine showed higher monomer conversion, with the amino acids acting as (co-)initiators, but their insertion along the PCL chains remained limited to chain endcapping. These results thus showed the possibility to synthesize enzymatically polycaprolactone-based chains bearing amino acids units. Such cysteine endcapped PCL materials could then find application in the biomedical field. Indeed, subsequent functionalization of these polyesters with drugs or bioactive molecules can be obtained, by derivatization of the amino acids, after removal of the protecting group.

Fatty acids are required for epidermal permeability barrier function.

Science.gov (United States)

Mao-Qiang, M; Elias, P M; Feingold, K R

1993-08-01

The permeability barrier is mediated by a mixture of ceramides, sterols, and free fatty acids arranged as extracellular lamellar bilayers in the stratum corneum. Whereas prior studies have shown that cholesterol and ceramides are required for normal barrier function, definitive evidence for the importance of nonessential fatty acids is not available. To determine whether epidermal fatty acid synthesis also is required for barrier homeostasis, we applied 5-(tetradecyloxy)-2-furancarboxylic acid (TOFA), an inhibitor of acetyl CoA carboxylase, after disruption of the barrier by acetone or tape stripping. TOFA inhibits epidermal fatty acid by approximately 50% and significantly delays barrier recovery. Moreover, coadministration of palmitate with TOFA normalizes barrier recovery, indicating that the delay is due to a deficiency in bulk fatty acids. Furthermore, TOFA treatment also delays the return of lipids to the stratum corneum and results in abnormalities in the structure of lamellar bodies, the organelle which delivers lipid to the stratum corneum. In addition, the organization of secreted lamellar body material into lamellar bilayers within the stratum corneum interstices is disrupted by TOFA treatment. Finally, these abnormalities in lamellar body and stratum corneum membrane structure are corrected by coapplication of palmitate with TOFA. These results demonstrate a requirement for bulk fatty acids in barrier homeostasis. Thus, inhibiting the epidermal synthesis of any of the three key lipids that form the extracellular, lipid-enriched membranes of the stratum corneum results in an impairment in barrier homeostasis.

Enhancing Cooperativity in Bifunctional Acid–Pd Catalysts with Carboxylic Acid-Functionalized Organic Monolayers

Energy Technology Data Exchange (ETDEWEB)

Coan, Patrick D. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Ellis, Lucas D. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Griffin, Michael B. [National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Schwartz, Daniel K. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Medlin, J. Will [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States

2018-03-01

Cooperative catalysts containing a combination of noble metal hydrogenation sites and Bronsted acid sites are critical for many reactions, including the deoxygenation (DO) of biomass-derived oxygenates in the upgrading of pyrolysis oil. One route toward the design of cooperative catalysts is to tether two different catalytically active functions so that they are in close proximity while avoiding undesirable interactions that can block active sites. Here, we deposited carboxylic acid (CA)-functionalized organophosphonate monolayers onto Al2O3-supported Pd nanoparticle catalysts to prepare bifunctional catalysts containing both Bronsted acid and metal sites. Modification with phosphonic acids (PAs) improved activity and selectivity for gas-phase DO reactions, but the degree of improvement was highly sensitive to both the presence and positioning of the CA group, suggesting a significant contribution from both the PA and CA sites. Short spacer lengths of 1-2 methylene groups between the phosphonate head and CA tail were found to yield the best DO rates and selectivities, whereas longer chains performed similarly to self-assembled monolayers having alkyl tails. Results from a combination of density functional theory and Fourier transform infrared spectroscopy suggested that the enhanced catalyst performance on the optimally positioned CAs was due to the generation of strong acid sites on the Al2O3 support adjacent to the metal. Furthermore, the high activity of these sites was found to result from a hydrogen-bonded cyclic structure involving cooperativity between the phosphonate head group and CA tail function. More broadly, these results indicate that functional groups tethered to supports via organic ligands can influence catalytic chemistry on metal nanoparticles.

The construction of an amino acid network for understanding protein structure and function.

Science.gov (United States)

Yan, Wenying; Zhou, Jianhong; Sun, Maomin; Chen, Jiajia; Hu, Guang; Shen, Bairong

2014-06-01

Amino acid networks (AANs) are undirected networks consisting of amino acid residues and their interactions in three-dimensional protein structures. The analysis of AANs provides novel insight into protein science, and several common amino acid network properties have revealed diverse classes of proteins. In this review, we first summarize methods for the construction and characterization of AANs. We then compare software tools for the construction and analysis of AANs. Finally, we review the application of AANs for understanding protein structure and function, including the identification of functional residues, the prediction of protein folding, analyzing protein stability and protein-protein interactions, and for understanding communication within and between proteins.

Synthesis and properties of amino acid functionalized water-soluble perylene diimides

Energy Technology Data Exchange (ETDEWEB)

Ma, Yongshan; Li, Xuemei; Wei, Xiaofeng; Jiang, Tianyi; Wu, Junsen; Ren, Huixue [Shandong Jianzhu University, Jinan (China)

2015-07-15

We prepared amino acid functionalized water-soluble perylene diimides: N,N'-bi(L-glutamic acid)-perylene-3,4;9,10-dicarboxylic diimide (1), N,N'-bi(L-phenylalanine acid)-perylene-3,4;9,10-dicarboxylic diimide (2), N,N'-bi(Lglutamic amine)-perylene-3,4;9,10-dicarboxylic diimide (3) and N,N'-bi(L-phenylalanine amine)-perylene-3,4;9,10-dicarboxylic diimide (4). The structures of 3 and 4 were confirmed by {sup 1}H NMR, FT-IR and MS. The maximal absorption bands of compound 1 and 2 in concentrated sulfuric acid were red-shifted for about 48 and 74 nm, respectively, compared with that of Perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA). Nearly no fluorescence was observed for compounds 1 and 2 in water, while compounds 3 and 4 were significantly water-soluble and had very high fluorescent quantum. The mechanism of the optical properties change was discussed, and the π-π stacking caused by H{sup +} led to the changes of fluorescence spectrum and absorption spectrum. The calculated molecular orbital energies and the frontier molecular orbital maps of compounds 1-2 based on density function theory (DFT) calculations were reported. Owing to the high water-soluble, the perylene derivatives 3 and 4 were successfully applied as high-performance fluorochromes for living hela cells imaging.

Improving surface functional properties of tofu whey-derived peptides by chemical modification with fatty acids.

Science.gov (United States)

Matemu, Athanasia Oswald; Katayama, Shigeru; Kayahara, Hisataka; Murasawa, Hisashi; Nakamura, Soichiro

2012-04-01

Effect of acylation with saturated fatty acids on surface functional properties of tofu whey-derived peptides was investigated. Tofu whey (TW) and soy proteins (7S, 11S, and acid-precipitated soy protein [APP]) were hydrolyzed by Protease M 'Amano' G, and resulting peptide mixtures were acylated with esterified fatty acids of different chain length (6C to 18C) to form a covalent linkage between the carboxyl group of fatty acid and the free amino groups of peptide. Acylation significantly (P properties of 7S, 11S, and APP peptides independent of fatty acid chain length. Acylation decreased water binding capacity although oil binding capacity of acylated tofu whey ultra filtered fraction (UFTW acids had shown significant higher surface hydrophobicity as in contrast with acylated UFTW acids can further affect functional properties of soy proteins. © 2012 Institute of Food Technologists®

Effects of Ascorbic Acid on Reproductive Functions of Male Wistar ...

African Journals Online (AJOL)

Effects of Ascorbic Acid on Reproductive Functions of Male Wistar Rats Exposed to Nicotine. ... smoke, and its effects on male reproductive system and fertility are well documented. ... The drugs were orally administered for thirty-five days.

Effects of Ascorbic Acid on Reproductive Functions of Male Wistar ...

African Journals Online (AJOL)

In conclusion, ascorbic acid supplement may suppress nicotine toxic effects on reproductive functions in male rats. ... et al., 2007). Nicotine is rapidly absorbed by the brain .... difference (LSD) test. p<0.05 was considered significant. Statistical ...

Omega-3 Fatty Acids Modulate TRPV4 Function through Plasma Membrane Remodeling.

Science.gov (United States)

Caires, Rebeca; Sierra-Valdez, Francisco J; Millet, Jonathan R M; Herwig, Joshua D; Roan, Esra; Vásquez, Valeria; Cordero-Morales, Julio F

2017-10-03

Dietary consumption of ω-3 polyunsaturated fatty acids (PUFAs), present in fish oils, is known to improve the vascular response, but their molecular targets remain largely unknown. Activation of the TRPV4 channel has been implicated in endothelium-dependent vasorelaxation. Here, we studied the contribution of ω-3 PUFAs to TRPV4 function by precisely manipulating the fatty acid content in Caenorhabditis elegans. By genetically depriving the worms of PUFAs, we determined that the metabolism of ω-3 fatty acids is required for TRPV4 activity. Functional, lipid metabolome, and biophysical analyses demonstrated that ω-3 PUFAs enhance TRPV4 function in human endothelial cells and support the hypothesis that lipid metabolism and membrane remodeling regulate cell reactivity. We propose a model whereby the eicosanoid's epoxide group location increases membrane fluidity and influences the endothelial cell response by increasing TRPV4 channel activity. ω-3 PUFA-like molecules might be viable antihypertensive agents for targeting TRPV4 to reduce systemic blood pressure. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Encapsulation of vegetable oils as source of omega-3 fatty acids for enriched functional foods.

Science.gov (United States)

Ruiz Ruiz, Jorge Carlos; Ortiz Vazquez, Elizabeth De La Luz; Segura Campos, Maira Rubi

2017-05-03

Polyunsaturated omega-3 fatty acids (PUFAs), a functional component present in vegetable oils, are generally recognized as being beneficial to health. Omega-3 PUFAs are rich in double bonds and unsaturated in nature; this attribute makes them highly susceptible to lipid oxidation and unfit for incorporation into long shelf life foods. The microencapsulation of oils in a polymeric matrix (mainly polysaccharides) offers the possibility of controlled release of the lipophilic functional ingredient and can be useful for the supplementation of foods with PUFAs. The present paper provides a literature review of different vegetable sources of omega-3 fatty acids, the functional effects of omega-3 fatty acids, different microencapsulation methods that can possibly be used for the encapsulation of oils, the properties of vegetable oil microcapsules, the effect of encapsulation on oxidation stability and fatty acid composition of vegetable oils, and the incorporation of long-chain omega-3 polyunsaturated fatty acids in foods.

Studies on Synthesis of Electrochemically Exfoliated Functionalized Graphene and Polylactic Acid/Ferric Phytate Functionalized Graphene Nanocomposites as New Fire Hazard Suppression Materials.

Science.gov (United States)

Feng, Xiaming; Wang, Xin; Cai, Wei; Qiu, Shuilai; Hu, Yuan; Liew, Kim Meow

2016-09-28

Practical application of functionalized graphene in polymeric nanocomposites is hampered by the lack of cost-effective and eco-friendly methods for its production. Here, we reported a facile and green electrochemical approach for preparing ferric phytate functionalized graphene (f-GNS) by simultaneously utilizing biobased phytic acid as electrolyte and modifier for the first time. Due to the presence of phytic acid, electrochemical exfoliation leads to low oxidized graphene sheets (a C/O ratio of 14.8) that are tens of micrometers large. Successful functionalization of graphene was confirmed by the appearance of phosphorus and iron peaks in the X-ray photoelectron spectrum. Further, high-performance polylactic acid/f-GNS nanocomposites are readily fabricated by a convenient masterbatch strategy. Notably, inclusion of well-dispersed f-GNS resulted in dramatic suppression on fire hazards of polylactic acid in terms of reduced peak heat-release rate (decreased by 40%), low CO yield, and formation of a high graphitized protective char layer. Moreover, obviously improvements in crystallization rate and thermal conductivities of polylactic acid nanocomposites were observed, highlighting its promising potential in practical application. This novel strategy toward the simultaneous exfoliation and functionalization for graphene demonstrates a simple yet very effective approach for fabricating graphene-based flame retardants.

The bonding of heavy metals on nitric acid-etched coal fly ashes functionalized with 2-mercaptoethanol or thioglycolic acid

International Nuclear Information System (INIS)

Muñoz, M.I.; Aller, A.J.; Littlejohn, D.

2014-01-01

Coal fly ash is a waste by-product of the coal fire industry, which generates many environmental problems. Alternative uses of this material would provide efficient solutions for this by-product. In this work, nitric acid-etched coal fly ash labelled with 2-mercaptoethanol or thioglycolic acid was assessed for retention of Al(III), As(III), Cu(II), Cd(II), Fe(III), Mn(II), Hg(II), Ni(II), Pb(II) and Zn(II) ions. The bonding characteristics between the organic compounds with the solid support, as well as with the metal ions, were evaluated using various surface analytical techniques. Visualization of the organically-functionalized coal fly ash particle was possible using scanning electron microscopy (SEM), while the elemental composition of the functionalized material, before and after retention of the metal ions, was obtained by energy dispersive (ED)-X ray spectrometry (XRS) and electrothermal atomic absorption spectrometry (ETAAS). Fourier transform infrared (FT-IR) spectrometry and Raman spectrometry were used to obtain information about the functional groups. It was found that some metal(oid) ions (As, Ni, Pb, Zn) were coordinated through the mercaptan group, while other metal(oid)s (Al, Cd, Cu, Fe, Hg, Mn) were apparently bonded to oxygen atoms. A low-cost and effective solid phase retention system for extraction of heavy metals from aqueous solutions was thus developed. - Graphical abstract: Nitric acid-etched coal fly ash labelled with 2-mercaptoethanol or thioglycolic acid was intended for the retention of heavy metals. The bonding characteristics between the organic compounds with the solid support, as well as with the metal ions, were evaluated using surface analytical techniques. - Highlights: • Coal fly ashes were organically-functionalized. • Organically-functionalized coal fly ashes were spectrometrically characterized. • Organically-functionalized coal fly ashes can be used as an effective solid sorbent for metal(oid)s. • This retention

Enzymatic Synthesis of Amino Acids Endcapped Polycaprolactone: A Green Route Towards Functional Polyesters

Directory of Open Access Journals (Sweden)

Stéphane W. Duchiron

2018-01-01

Full Text Available ε-caprolactone (CL has been enzymatically polymerized using α-amino acids based on sulfur (methionine and cysteine as (co-initiators and immobilized lipase B of Candida antarctica (CALB as biocatalyst. In-depth characterizations allowed determining the corresponding involved mechanisms and the polymers thermal properties. Two synthetic strategies were tested, a first one with direct polymerization of CL with the native amino acids and a second one involving the use of an amino acid with protected functional groups. The first route showed that mainly polycaprolactone (PCL homopolymer could be obtained and highlighted the lack of reactivity of the unmodified amino acids due to poor solubility and affinity with the lipase active site. The second strategy based on protected cysteine showed higher monomer conversion, with the amino acids acting as (co-initiators, but their insertion along the PCL chains remained limited to chain endcapping. These results thus showed the possibility to synthesize enzymatically polycaprolactone-based chains bearing amino acids units. Such cysteine endcapped PCL materials could then find application in the biomedical field. Indeed, subsequent functionalization of these polyesters with drugs or bioactive molecules can be obtained, by derivatization of the amino acids, after removal of the protecting group.

Synthesis of Ricinoleic Acid Estolides by the Esterification of Ricinoleic Acids Using Functional Acid Ionic Liquids as Catalysts.

Science.gov (United States)

Wang, Gaoshang; Sun, Shangde

2017-07-01

Estolides of ricinoleic acid (RA) have been used as lubricants and pigment dispersant in many industries. In this paper, functional acid ionic liquids (ILs) were firstly used as catalysts to prepare RA estolides by the esterification of RAs in solvent-free system. Different ILs were used as catalysts for the esterification. Effect of reaction variables (IL amount, reaction temperature and reaction time) on the esterification were also investigated and optimized using response surface methodology (RSM). Among all tested ILs, [BSO 3 HMIM]TS showed the best performance for the esterification. Arrhenius equation for the esterification was lnV 0 =14.897-7558.7/T, and the activation energy (Ea) was 62.84 kJ/mol. A high degree of polymerization with an acid value of 48.0±2.5 mg KOH/g was achieved at the optimized conditions (IL load 12%, reaction temperature 140°C, and reaction time 12 h). The effect of reaction variables on the esterification decreased in the order of catalyst loading of IL > reaction temperature > reaction time.

Functional properties and fatty acids profile of different beans varieties.

Science.gov (United States)

Lo Turco, Vincenzo; Potortì, Angela Giorgia; Rando, Rossana; Ravenda, Pietro; Dugo, Giacomo; Di Bella, Giuseppa

2016-10-01

Dried seeds of four varieties of Phaseolus vulgaris, three of Vigna unguiculata ssp. unguiculata and two of Vigna angularis grown and marketed in Italy, Mexico, India, Japan, Ghana and Ivory Coast were analysed for fatty acids content. In oils from seeds of P. vulgaris, the main fatty acids were linolenic (34.7-41.5%) and linoleic (30.7-40.3%), followed by palmitic (10.7-16.8%). The first three aforementioned fatty acids in the lipid fraction of V. unguiculata varieties were 28.4, 28.7 and 26.2%, respectively; while in V. angularis varieties, main fatty acids were linoleic (36.4-39.1%) and palmitic (26.9-33.3%), followed by linolenic (17.9-22.2%). Statistical analyses indicate that botanical species play a rule in bean fatty acids distribution, while the same was not verified for geographical origin. Furthermore, the atherogenic index (AI) and the thrombogenic index (TI) were investigated for health and nutritional information. The results showed that these wide spread legumes have functional features to human health.

Functional role of ascorbic acid in bread-making | Dadzie-Mensah ...

African Journals Online (AJOL)

bread characteristics. Various levels of ascorbic acid and bromate were used in the bread production to compare critical functional properties of bread. The results showed that the specific volume of the loaves increased from 2.80 cm3/g ...

Chemoselective, Substrate-directed Fluorination of Functionalized Cyclopentane β-Amino Acids.

Science.gov (United States)

Kiss, Loránd; Nonn, Melinda; Sillanpää, Reijo; Haukka, Matti; Fustero, Santos; Fülöp, Ferenc

2016-12-06

This work describes a substrate-directed fluorination of some highly functionalized cyclopentane derivatives. The cyclic products incorporating CH 2 F or CHF 2 moieties in their structure have been synthesized from diexo- or diendo-norbornene β-amino acids following a stereocontrolled strategy. The synthetic study was based on an oxidative transformation of the ring carbon-carbon double bond of the norbornene β-amino acids, followed by transformation of the resulted "all cis" and "trans" diformyl intermediates by fluorination with "chemodifferentiation". © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanistic evidence for a ring-opening pathway in the Pd-catalyzed direct arylation of benzoxazoles

DEFF Research Database (Denmark)

Sanchez, R.S.; Zhuravlev, Fedor

2007-01-01

The direct Pd-catalyzed arylation of 5-substituted benzoxazoles, used as a mechanistic model for 1,3-azoles, was investigated experimentally and computationally. The results of the primary deuterium kinetic isotope effect, Hammett studies, and H/D exchange were shown to be inconsistent with the r......The direct Pd-catalyzed arylation of 5-substituted benzoxazoles, used as a mechanistic model for 1,3-azoles, was investigated experimentally and computationally. The results of the primary deuterium kinetic isotope effect, Hammett studies, and H/D exchange were shown to be inconsistent...... with the rate-limiting electrophilic or concerted palladation. A mechanism, proposed on the basis of kinetic and computational studies, includes generation of isocyanophenolate as the key step. The DFT calculations suggest that the overall catalytic cycle is facile and is largely controlled by the C-H acidity...

Quantitative determination of acidic groups in functionalized graphene by direct titration

Czech Academy of Sciences Publication Activity Database

Ederer, J.; Janoš, P.; Ecorchard, Petra; Štengl, Václav; Bělčická, Zuzana; Šťastný, Martin; Pop-Georgievski, Ognen; Dohnal, V.

2016-01-01

Roč. 103, JUN (2016), s. 44-53 ISSN 1381-5148 R&D Projects: GA ČR(CZ) GA14-05146S Institutional support: RVO:61388980 ; RVO:61389013 Keywords : Acid-base titration * Carboxylic functional groups * Graphene oxide * Phenolic functional groups * Proton-binding model Subject RIV: CA - Inorganic Chemistry ; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 3.151, year: 2016

Urea dimethacrylates functionalized with bisphosphonate/bisphosphonic acid for improved dental materials

OpenAIRE

Güven, Melek Naz; Guven, Melek Naz; Akyol, Ece; Duman, Fatma Demir; Acar, Havva Yağcı; Acar, Havva Yagci; Karahan, Özlem; Karahan, Ozlem; Avcı, Duygu; Avci, Duygu

2017-01-01

Incorporation of bisphosphonate/bisphosphonic acid groups in dental monomer structures should increase interaction of these monomers with dental tissue as these groups have strong affinity for hydroxyapatite. Therefore, new urea dimethacrylates functionalized with bisphosphonate (1a, 1b) and bisphosphonic acid (2a, 2b) groups are synthesized and evaluated for dental applications. Monomers 1a and 1b are synthesized from 2isocyanatoethyl methacrylate (IEM) and two bisphosphonated amines (BPA1 a...

Evolution of sequence-defined highly functionalized nucleic acid polymers

Science.gov (United States)

Chen, Zhen; Lichtor, Phillip A.; Berliner, Adrian P.; Chen, Jonathan C.; Liu, David R.

2018-03-01

The evolution of sequence-defined synthetic polymers made of building blocks beyond those compatible with polymerase enzymes or the ribosome has the potential to generate new classes of receptors, catalysts and materials. Here we describe a ligase-mediated DNA-templated polymerization and in vitro selection system to evolve highly functionalized nucleic acid polymers (HFNAPs) made from 32 building blocks that contain eight chemically diverse side chains on a DNA backbone. Through iterated cycles of polymer translation, selection and reverse translation, we discovered HFNAPs that bind proprotein convertase subtilisin/kexin type 9 (PCSK9) and interleukin-6, two protein targets implicated in human diseases. Mutation and reselection of an active PCSK9-binding polymer yielded evolved polymers with high affinity (KD = 3 nM). This evolved polymer potently inhibited the binding between PCSK9 and the low-density lipoprotein receptor. Structure-activity relationship studies revealed that specific side chains at defined positions in the polymers are required for binding to their respective targets. Our findings expand the chemical space of evolvable polymers to include densely functionalized nucleic acids with diverse, researcher-defined chemical repertoires.

Biomimetic L-aspartic acid-derived functional poly(ester amide)s for vascular tissue engineering.

Science.gov (United States)

Knight, Darryl K; Gillies, Elizabeth R; Mequanint, Kibret

2014-08-01

Functionalization of polymeric biomaterials permits the conjugation of cell signaling molecules capable of directing cell function. In this study, l-phenylalanine and l-aspartic acid were used to synthesize poly(ester amide)s (PEAs) with pendant carboxylic acid groups through an interfacial polycondensation approach. Human coronary artery smooth muscle cell (HCASMC) attachment, spreading and proliferation was observed on all PEA films. Vinculin expression at the cell periphery suggested that HCASMCs formed focal adhesions on the functional PEAs, while the absence of smooth muscle α-actin (SMαA) expression implied the cells adopted a proliferative phenotype. The PEAs were also electrospun to yield nanoscale three-dimensional (3-D) scaffolds with average fiber diameters ranging from 130 to 294nm. Immunoblotting studies suggested a potential increase in SMαA and calponin expression from HCASMCs cultured on 3-D fibrous scaffolds when compared to 2-D films. X-ray photoelectron spectroscopy and immunofluorescence demonstrated the conjugation of transforming growth factor-β1 to the surface of the functional PEA through the pendant carboxylic acid groups. Taken together, this study demonstrates that PEAs containing aspartic acid are viable biomaterials for further investigation in vascular tissue engineering. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Surface functionalization of two-dimensional metal chalcogenides by Lewis acid-base chemistry

Science.gov (United States)

Lei, Sidong; Wang, Xifan; Li, Bo; Kang, Jiahao; He, Yongmin; George, Antony; Ge, Liehui; Gong, Yongji; Dong, Pei; Jin, Zehua; Brunetto, Gustavo; Chen, Weibing; Lin, Zuan-Tao; Baines, Robert; Galvão, Douglas S.; Lou, Jun; Barrera, Enrique; Banerjee, Kaustav; Vajtai, Robert; Ajayan, Pulickel

2016-05-01

Precise control of the electronic surface states of two-dimensional (2D) materials could improve their versatility and widen their applicability in electronics and sensing. To this end, chemical surface functionalization has been used to adjust the electronic properties of 2D materials. So far, however, chemical functionalization has relied on lattice defects and physisorption methods that inevitably modify the topological characteristics of the atomic layers. Here we make use of the lone pair electrons found in most of 2D metal chalcogenides and report a functionalization method via a Lewis acid-base reaction that does not alter the host structure. Atomic layers of n-type InSe react with Ti4+ to form planar p-type [Ti4+n(InSe)] coordination complexes. Using this strategy, we fabricate planar p-n junctions on 2D InSe with improved rectification and photovoltaic properties, without requiring heterostructure growth procedures or device fabrication processes. We also show that this functionalization approach works with other Lewis acids (such as B3+, Al3+ and Sn4+) and can be applied to other 2D materials (for example MoS2, MoSe2). Finally, we show that it is possible to use Lewis acid-base chemistry as a bridge to connect molecules to 2D atomic layers and fabricate a proof-of-principle dye-sensitized photosensing device.

Esterification of oil adsorbed on palm decanter cake into methyl ester using sulfonated rice husk ash as heterogeneous acid catalyst

Science.gov (United States)

Hindryawati, Noor; Erwin, Maniam, Gaanty Pragas

2017-02-01

Palm Decanter cake (PDC) which is categorized as the waste from palm oil mill has been found to contain residual crude palm oil. The oil adsorbed on the PDC (PDC-oil) can be extracted and potentially used as feedstock for biodiesel production. Feedstock from waste like PDC-oil is burdened with high free fatty acids (FFAs) which make the feedstock difficult to be converted into biodiesel using basic catalyst. Therefore, in this study, a solid acid, RHA-SO3H catalyst was synthesized by sulfonating rice husk ash (RHA) with concentrated sulfuric acid. The RHA-SO3H prepared was characterized with TGA, FTIR, BET, XRD, FE-SEM, and Hammett indicators (methyl red, bromophenol blue, and crystal violet). PDC was found to have about 11.3 wt. % oil recovered after 1 hour extraction using ultrasound method. The presence of sulfonate group was observed in IR spectrum, and the surface area of RHA-SO3H was reduced to 37 m2.g-1 after impregnation of sulfonate group. The RHA-SO3H catalyst showed that it can work for both esterification of free fatty acid which is present in PDC-oil, and transesterification of triglycerides into methyl ester. The results showed highest methyl ester content of 70.2 wt.% at optimal conditions, which was 6 wt.% catalyst amount, methanol to oil molar ratio of 17:1 for 5 hours at 120 °C.

Plant amino acid-derived vitamins: biosynthesis and function.

Science.gov (United States)

Miret, Javier A; Munné-Bosch, Sergi

2014-04-01

Vitamins are essential organic compounds for humans, having lost the ability to de novo synthesize them. Hence, they represent dietary requirements, which are covered by plants as the main dietary source of most vitamins (through food or livestock's feed). Most vitamins synthesized by plants present amino acids as precursors (B1, B2, B3, B5, B7, B9 and E) and are therefore linked to plant nitrogen metabolism. Amino acids play different roles in their biosynthesis and metabolism, either incorporated into the backbone of the vitamin or as amino, sulfur or one-carbon group donors. There is a high natural variation in vitamin contents in crops and its exploitation through breeding, metabolic engineering and agronomic practices can enhance their nutritional quality. While the underlying biochemical roles of vitamins as cosubstrates or cofactors are usually common for most eukaryotes, the impact of vitamins B and E in metabolism and physiology can be quite different on plants and animals. Here, we first aim at giving an overview of the biosynthesis of amino acid-derived vitamins in plants, with a particular focus on how this knowledge can be exploited to increase vitamin contents in crops. Second, we will focus on the functions of these vitamins in both plants and animals (and humans in particular), to unravel common and specific roles for vitamins in evolutionary distant organisms, in which these amino acid-derived vitamins play, however, an essential role.

Visual functions in phenylketonuria-evaluating the dopamine and long-chain polyunsaturated fatty acids depletion hypotheses.

Science.gov (United States)

Gramer, Gwendolyn; Förl, Birgit; Springer, Christina; Weimer, Petra; Haege, Gisela; Mackensen, Friederike; Müller, Edith; Völcker, Hans Eberhard; Hoffmann, Georg Friedrich; Lindner, Martin; Krastel, Hermann; Burgard, Peter

2013-01-01

In phenylketonuria presymptomatic treatment following newborn screening prevents severe mental and physical impairment. The reasons for subtle impairments of cerebral functions despite early treatment remain unclear. We assessed a broad spectrum of visual functions in early-treated patients with phenylketonuria and evaluated two hypotheses-the dopamine and the long-chain polyunsaturated fatty acids (LCPUFAs) depletion hypotheses. Contrast sensitivity, colour vision, electroretinography, frequency doubling technology campimetry (FDT), and their relation with blood phenylalanine and docosahexaenoic acid levels were assessed in 36 patients with phenylketonuria and 18 age-matched healthy controls. Contrast sensitivity was significantly lower and total error scores in colour vision significantly higher in patients than controls. Electroretinography results differed significantly between patients and controls. We found a trend for the effect of phenylalanine-levels on contrast sensitivity and a significant effect on colour vision/FDT results. Docosahexaenoic acid levels in erythrocytes were not associated with visual functions. This is the first evaluation of visual functions in phenylketonuria using a comprehensive ophthalmological test battery. We found no evidence supporting the long-chain polyunsaturated fatty acids depletion hypothesis. However, the effect of phenylalanine-levels on visual functions suggests that imbalance between phenylalanine and tyrosine may affect retinal dopamine levels in phenylketonuria. This is supported by the similar patterns of visual functions in patients with phenylketonuria observed in our study and patients with Parkinson's disease. Copyright © 2012 Elsevier Inc. All rights reserved.

Effects of salicylic acid on post-ischaemic ventricular function and purine efflux in isolated mouse hearts.

Science.gov (United States)

Farthing, Don; Gehr, Lynne; Karnes, H Thomas; Sica, Domenic; Gehr, Todd; Larus, Terri; Farthing, Christine; Xi, Lei

2007-01-01

Acetyl salicylic acid (aspirin) is one of the most widely used drugs in the world. Various plasma concentrations of aspirin and its predominant metabolite, salicylic acid, are required for its antiarthritic (1.5-2.5 mM), anti-inflammatory (0.5-5.0 mM) or antiplatelet (0.18-0.36 mM) actions. A recent study demonstrated the inhibitory effects of both aspirin and salicylic acid on oxidative phosphorylation and ATP synthesis in isolated rat cardiac mitochondria in a dose-dependent manner (0-10 mM concentration range). In this context, the present study was conducted to determine the effects of salicylic acid on inosine efflux (a potential biomarker of acute cardiac ischaemia) as well as cardiac contractile function in the isolated mouse heart following 20 min of zero-flow global ischaemia. Inosine efflux was found at significantly higher concentrations in ischaemic hearts perfused with Krebs buffer fortified with 1.0 mM salicylic acid compared with those without salicylic acid (12575+/-3319 vs. 1437+/-348 ng ml(-1) min(-1), mean+/-SEM, n=6 per group, psalicylic acid potentiates 8.8-fold ATP nucleotide purine catabolism into its metabolites (e.g. inosine, hypoxanthine). Salicylic acid (0.1 or 1.0 mM) did not appreciably inhibit purine nucleoside phosphorylase (the enzyme converts inosine to hypoxanthine) suggesting the augmented inosine efflux was due to the salicylic acid effect on upstream elements of cellular respiration. Whereas post-ischaemic cardiac function was further depressed by 1.0 mM salicylic acid, perfusion with 0.1 mM salicylic acid led to a remarkable functional improvement despite moderately increased inosine efflux (2.7-fold). We conclude that inosine is a sensitive biomarker for detecting cardiac ischaemia and salicylic acid-induced effects on cellular respiration. However, the inosine efflux level appears to be a poor predictor of the individual post-ischaemic cardiac functional recovery in this ex vivo model.

Preparation and Characterization of Sulfonic Acid Functionalized Silica and Its Application for the Esterification of Ethanol and Maleic Acid

Science.gov (United States)

Sirsam, Rajkumar; Usmani, Ghayas

2016-04-01

The surface of commercially available silica gel, 60-200 mesh size, was modified with sulfonic acid through surface activation, grafting of 3-Mercaptopropyltrimethoxysilane, oxidation and acidification of 3-Mercaptopropylsilica. Sulfonic Acid Functionalization of Silica (SAFS) was confirmed by Fourier Transform Infra-red (FTIR) spectroscopy and thermal gravimetric analysis. Acid-base titration was used to estimate the cation exchange capacity of the SAFS. Catalytic activity of SAFS was judged for the esterification of ethanol with maleic acid. An effect of different process parameters viz. molar ratio, catalyst loading, speed of agitation and temperature were studied and optimized by Box Behnken Design (BBD) of Response Surface Methodology (RSM). Quadratic model developed by BBD-RSM reasonably satisfied an experimental and predicted values with correlation coefficient value R2 = 0.9504.

Serum uric acid and renal function in patients with type 1 diabetes: a nationwide study in Brazil.

Science.gov (United States)

Pizarro, Marcela Haas; Santos, Deborah Conte; Barros, Bianca Senger Vasconcelos; de Melo, Laura Gomes Nunes; Gomes, Marilia Brito

2018-01-01

Diabetes nephropathy is a microvascular complication associated with high morbidity and mortality in patients with type 1 diabetes, and its pathogenesis is not fully understood. Our aim was to evaluate the association between levels of serum uric acid and renal function assessed by glomerular filtration rate (GFR) and albuminuria in patients with type 1 diabetes. This is a multicenter, cross-sectional, observational study with 1686 patients, conducted between August 2011 and August 2014 in 14 public clinics from ten Brazilian cities. Renal function was estimated by CKD-EPI (adults) and by Schwartz (adolescents). We analyzed 1686 patients, aged 30.1 ± 12.0, with 15.4 ± 9.3 years of duration of diabetes; 55.8% were female and 54.0% were Caucasians. Serum uric acid was related to renal function, with a mean of 4.8 ± 1.4 (in the normal renal function group) vs 5.2 ± 2.0 (GFR ≥ 60 ml/min and albuminuria) vs 6.5 ± 2.6 mg/dl (GFR uric acid and GFR (r = - 0.316, p uric acid. Considering only patients with normal renal function (n = 1170), a decrease of 2.04 ml/min in the GFR for every increase of 1 mg/dl in Serum uric acid was noted using multivariate analysis. Patients with higher levels of serum uric acid have worse renal function, independently of HbA1c or duration of diabetes, which persisted even in patients with normal renal function. Further prospective studies are necessary to establish if patients with higher serum uric acid may have an elevated risk for developing chronic kidney disease.

Omega-3 fatty acid supplementation and cognitive function: are smaller dosages more beneficial?

Directory of Open Access Journals (Sweden)

Abubakari AR

2014-09-01

Full Text Available Abdul-Razak Abubakari,1 Mohammad-Mahdi Naderali,2 Ebrahim K Naderali3 1School of Health and Life Sciences, Glasgow Caledonian University, London, UK; 2Blue Coat School, Liverpool, UK; 3School of Health Sciences, Liverpool Hope University, Hope Park Campus, Liverpool, UK Abstract: As longevity increases, so does the global prevalence of cognitive dysfunction. Numerous lifestyle and/or dietary interventions such as omega-3 fatty acids have been suggested to improve memory. Therefore, this study examined the consistency and strength of the impact of supplementation of omega-3 fatty acids on overall cognitive function using systematic reviews and meta-analytic methods. Of 905 studies retrieved from all searches, 12 randomized controlled trials were included in the meta-analysis. There were differences between studies reporting outcomes for single memory function parameters. Subgroup analysis of doses used (low versus high indicated that subjects receiving low (<1.73 g/day doses of omega-3 fatty acids had a significant reduction in cognitive decline rate (-0.07, 95% confidence interval -0.01, -0.02 but there was no evidence for beneficial effects at higher doses (+0.04, 95% confidence interval -0.06, +0.14 compared with the placebo group. This study suggests that omega-3 fatty acids may be beneficial in preventing memory decline at lower doses. Keywords: cognitive impairment, Alzheimer's disease, dietary fatty acids, omega-3, docosahexaenoic acid

Structure and functioning of the acid-base system in the Baltic Sea

Science.gov (United States)

Kuliński, Karol; Schneider, Bernd; Szymczycha, Beata; Stokowski, Marcin

2017-12-01

The marine acid-base system is relatively well understood for oceanic waters. Its structure and functioning is less obvious for the coastal and shelf seas due to a number of regionally specific anomalies. In this review article we collect and integrate existing knowledge of the acid-base system in the Baltic Sea. Hydrographical and biogeochemical characteristics of the Baltic Sea, as manifested in horizontal and vertical salinity gradients, permanent stratification of the water column, eutrophication, high organic-matter concentrations and high anthropogenic pressure, make the acid-base system complex. In this study, we summarize the general knowledge of the marine acid-base system as well as describe the peculiarities identified and reported for the Baltic Sea specifically. In this context we discuss issues such as dissociation constants in brackish water, different chemical alkalinity models including contributions by organic acid-base systems, long-term changes in total alkalinity, anomalies of borate alkalinity, and the acid-base effects of biomass production and mineralization. Finally, we identify research gaps and specify limitations concerning the Baltic Sea acid-base system.

Acidic nanoparticles are trafficked to lysosomes and restore an acidic lysosomal pH and degradative function to compromised ARPE-19 cells.

Directory of Open Access Journals (Sweden)

Gabriel C Baltazar

Full Text Available Lysosomal enzymes function optimally in acidic environments, and elevation of lysosomal pH can impede their ability to degrade material delivered to lysosomes through autophagy or phagocytosis. We hypothesize that abnormal lysosomal pH is a key aspect in diseases of accumulation and that restoring lysosomal pH will improve cell function. The propensity of nanoparticles to end up in the lysosome makes them an ideal method of delivering drugs to lysosomes. This study asked whether acidic nanoparticles could traffic to lysosomes, lower lysosomal pH and enhance lysosomal degradation by the cultured human retinal pigmented epithelial cell line ARPE-19. Acidic nanoparticles composed of poly (DL-lactide-co-glycolide (PLGA 502 H, PLGA 503 H and poly (DL-lactide (PLA colocalized to lysosomes of ARPE-19 cells within 60 min. PLGA 503 H and PLA lowered lysosomal pH in cells compromised by the alkalinizing agent chloroquine when measured 1 hr. after treatment, with acidification still observed 12 days later. PLA enhanced binding of Bodipy-pepstatin-A to the active site of cathepsin D in compromised cells. PLA also reduced the cellular levels of opsin and the lipofuscin-like autofluorescence associated with photoreceptor outer segments. These observations suggest the acidification produced by the nanoparticles was functionally effective. In summary, acid nanoparticles lead to a rapid and sustained lowering of lysosomal pH and improved degradative activity.

Functional amino acids in nutrition and health.

Science.gov (United States)

Wu, Guoyao

2013-09-01

The recent years have witnessed growing interest in biochemistry, physiology and nutrition of amino acids (AA) in growth, health and disease of humans and other animals. This results from the discoveries of AA in cell signaling involving protein kinases, G protein-coupled receptors, and gaseous molecules (i.e., NO, CO and H2S). In addition, nutritional studies have shown that dietary supplementation with several AA (e.g., arginine, glutamine, glutamate, leucine, and proline) modulates gene expression, enhances growth of the small intestine and skeletal muscle, or reduces excessive body fat. These seminal findings led to the new concept of functional AA, which are defined as those AA that participate in and regulate key metabolic pathways to improve health, survival, growth, development, lactation, and reproduction of the organisms. Functional AA hold great promise in prevention and treatment of metabolic diseases (e.g., obesity, diabetes, and cardiovascular disorders), intrauterine growth restriction, infertility, intestinal and neurological dysfunction, and infectious disease (including viral infections).

Effect of oral administration of terephthalic acid on testicular functions of rats

International Nuclear Information System (INIS)

Cui Lunbiao; Dai Guidong; Xu Lichun; Wang Shouling; Song Ling; Zhao Renzhen; Xiao Hang; Zhou Jianwei; Wang Xinru

2004-01-01

To investigate the toxic effect of terephthalic acid (TPA) on testicular functions of rats, male Sprague-Dawley rats were orally administered TPA in diet at the levels 0 (control), 0.2, 1 and 5% for 90 days. Testicular functions were assessed by histopathology, testicular sperm head counts, daily sperm production, sperm motility (measured by computer-assisted sperm analysis, CASA), biochemical indices (marker testicular enzymes), and serum testosterone. Oral feeding with terephthalic acid did not cause body and testes weight loss in TPA-treated groups. Histopathologically, damages of spermatogenic cells and Sertoli cells were observed by electron microscope, testicular sperm head counts, daily sperm production, and activities of sorbitol dehydrogenase (SDH) were decreased significantly in the 5% TPA group. The motility of spermatozoa was reduced significantly in all treated groups, which was correlated with administration doses. Serum testosterone concentrations were not declined in treated groups. In conclusion, TPA can cause impairment of testicular functions. The primary sites of action may be spermatogenic cells and Sertoli cells. The results of the present study provide first information of TPA on testicular functions in male rats

Study of application properties of novel trisazo hetero bi-functional reactive dyes based on j-acid derivatives for cotton

International Nuclear Information System (INIS)

Mokhtari, Javad; Akbarzadeh, A; Phillips, D A S; Taylor, J A

2009-01-01

Three novel trisazo hetero bi-functional reactive dyes based on J-acid derivatives were prepared using the diazonium salt of [4-(4-sulphophenylazo-)-2,5-dimethylazobenzene-2-sulphonic acid] and a hetero bi-functional coupling component, derived from 1-hydroxy-6-aminonapthalene-3-sulphonic acid (J-acid), 1-hydroxy-6- methylaminonapthalene-3-sulphonic acid (methyl J-acid), and 1-hydroxy-6-aminonaphthalene-3,5-disulphonic acid (sulpho J-acid). On balance, the dye derived from sulpho J-acid displayed the most attractive set of technical properties, building up and fixing more efficiently than those derived from J-acid and methyl J-acid. In addition, the sulpho J-acid based dye offered better migration and, therefore, level dyeing and ease of wash off. (author)

Sensitive Determination of 6-Thioguanine Using Caffeic Acid-functionalized Fe3O4 Nanoparticles as an Electrochemical Sensor

Science.gov (United States)

Amir, Md.; Tunesi, Mawada M.; Soomro, Razium A.; Baykal, Abdülhadi; Kalwar, Nazar H.

2018-04-01

The study demonstrates the potential application of caffeic acid-functionalized magnetite nanoparticles (CA-Fe3O4 NPs) as an effective electrode modifying material for the electrochemical oxidation of the 6-thioguanine (6-TG) drug. The functionalized Fe3O4 NPs were prepared using simple wet-chemical methodology where the used caffeic acid acted simultaneously as growth controlling and functionalizing agent. The study discusses the influence of an effective functionalization on the signal sensitivity observed for the electro-oxidation of 6-TG over CA-Fe3O4 NPs in comparison to a glassy carbon electrode modified with bare and nicotinic acid (NA)-functionalized Fe3O4 NPs. The experiment results provided sufficient evidence to support the importance of favorable functionality to achieve higher signal sensitivity for the electro-oxidation of 6-TG. The presence of favorable interactions between the active functional moieties of caffeic acid and 6-TG synergized with the greater surface area of magnetic NPs produces a stable electro-oxidation signal within the working range of 0.01-0.23 μM with sensitive up to 0.001 μM. Additionally, the sensor showed the strong anti-interference potential against the common co-existing drug molecules such as benzoic acid, acetaminophen, epinephrine, norepinephrine, glucose, ascorbic acid and l-cysteine. In addition, the successful quantification of 6-TG from the commercial tablets obtained from local pharmacy further signified the practical capability of the discussed sensor.

Effect of fatty acids on functional properties of normal wheat and waxy wheat starches: A structural basis.

Science.gov (United States)

Wang, Shujun; Wang, Jinrong; Yu, Jinglin; Wang, Shuo

2016-01-01

The effects of three saturated fatty acids on functional properties of normal wheat and waxy wheat starches were investigated. The complexing index (CI) of normal wheat starch-fatty acid complexes decreased with increasing carbon chain length. In contrast, waxy wheat starch-fatty acid complexes presented much lower CI. V-type crystalline polymorphs were formed between normal wheat starch and three fatty acids, with shorter chain fatty acids producing more crystalline structure. FTIR and Raman spectroscopy presented the similar results with XRD. The formation of amylose-fatty acid complex inhibited granule swelling, gelatinization progression, retrogradation and pasting development of normal wheat starch, with longer chain fatty acids showing greater inhibition. Amylopectin can also form complexes with fatty acids, but the amount of complex was too little to be detected by XRD, FTIR, Raman and DSC. As a consequence, small changes were observed in the functional properties of waxy wheat starch with the addition of fatty acids. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of the frequency of functional SH3 domains with different limited sets of amino acids using mRNA display.

Directory of Open Access Journals (Sweden)

Junko Tanaka

Full Text Available Although modern proteins consist of 20 different amino acids, it has been proposed that primordial proteins consisted of a small set of amino acids, and additional amino acids have gradually been recruited into the genetic code. This hypothesis has recently been supported by comparative genome sequence analysis, but no direct experimental approach has been reported. Here, we utilized a novel experimental approach to test a hypothesis that native-like globular proteins might be easily simplified by a set of putative primitive amino acids with retention of its structure and function than by a set of putative new amino acids. We performed in vitro selection of a functional SH3 domain as a model from partially randomized libraries with different sets of amino acids using mRNA display. Consequently, a library rich in putative primitive amino acids included a larger number of functional SH3 sequences than a library rich in putative new amino acids. Further, the functional SH3 sequences were enriched from the primitive library slightly earlier than from a randomized library with the full set of amino acids, while the function and structure of the selected SH3 proteins with the primitive alphabet were comparable with those from the 20 amino acid alphabet. Application of this approach to various combinations of codons in protein sequences may be useful not only for clarifying the precise order of the amino acid expansion in the early stages of protein evolution but also for efficiently creating novel functional proteins in the laboratory.

Conjugated linoleic acids as functional food: an insight into their health benefits

OpenAIRE

Benjamin Sailas; Spener Friedrich

2009-01-01

Abstract This review evaluates the health benefits of the functional food, conjugated linoleic acids (CLA) - a heterogeneous group of positional and geometric isomers of linoleic acid predominantly found in milk, milk products, meat and meat products of ruminants. During the past couple of decades, hundreds of reports - principally based on in vitro, microbial, animal, and of late clinical trials on humans - have been accumulating with varying biological activities of CLA isomers. These studi...

Highly thermal-stable and functional cellulose nanocrystals and nanofibrils produced using fully recyclable organic acids

Science.gov (United States)

Liheng Chen; Junyong Zhu; Carlos Baez; Peter Kitin; Thomas Elder

2016-01-01

Here we report the production of highly thermal stable and functional cellulose nanocrystals (CNC) and nanofibrils (CNF) by hydrolysis using concentrated organic acids. Due to their low water solubility, these solid organic acids can be easily recovered after hydrolysis reactions through crystallization at a lower or ambient temperature. When dicarboxylic acids were...

Hydrogen-bond acidic functionalized carbon nanotubes (CNTs) with covalently-bound hexafluoroisopropanol groups

Energy Technology Data Exchange (ETDEWEB)

Fifield, Leonard S.; Grate, Jay W.

2010-06-01

Fluorinated hydrogen-bond acidic groups are directly attached to the backbone of single walled carbon nanotubes (SWCNTs) without the introduction of intermediate electron donating surface groups. Hexafluoroalcohol functional groups are exceptionally strong hydrogen bond acids, and are added to the nanotube surface using the aryl diazonium approach to create hydrogen-bond acidic carbon nanotube (CNT) surfaces. These groups can promote strong hydrogen-bonding interactions with matrix materials in composites or with molecular species to be concentrated and sensed. In the latter case, this newly developed material is expected to find useful application in chemical sensors and in CNT-based preconcentrator devices for the detection of pesticides, chemical warfare agents and explosives.

Feature-Based Classification of Amino Acid Substitutions outside Conserved Functional Protein Domains

Directory of Open Access Journals (Sweden)

Branislava Gemovic

2013-01-01

Full Text Available There are more than 500 amino acid substitutions in each human genome, and bioinformatics tools irreplaceably contribute to determination of their functional effects. We have developed feature-based algorithm for the detection of mutations outside conserved functional domains (CFDs and compared its classification efficacy with the most commonly used phylogeny-based tools, PolyPhen-2 and SIFT. The new algorithm is based on the informational spectrum method (ISM, a feature-based technique, and statistical analysis. Our dataset contained neutral polymorphisms and mutations associated with myeloid malignancies from epigenetic regulators ASXL1, DNMT3A, EZH2, and TET2. PolyPhen-2 and SIFT had significantly lower accuracies in predicting the effects of amino acid substitutions outside CFDs than expected, with especially low sensitivity. On the other hand, only ISM algorithm showed statistically significant classification of these sequences. It outperformed PolyPhen-2 and SIFT by 15% and 13%, respectively. These results suggest that feature-based methods, like ISM, are more suitable for the classification of amino acid substitutions outside CFDs than phylogeny-based tools.

Mechanistic Investigation of the Ruthenium–N-Heterocyclic-Carbene-Catalyzed Amidation of Alcohols and Amines

DEFF Research Database (Denmark)

Makarov, Ilya; Fristrup, Peter; Madsen, Robert

2012-01-01

The mechanism of the ruthenium–N-heterocyclic-carbene-catalyzed formation of amides from alcohols and amines was investigated by experimental techniques (Hammett studies, kinetic isotope effects) and by a computational study by using dispersion-corrected density functional theory (DFT/ M06...

Preparation of Phosphonic Acid Functionalized Graphene Oxide-modified Aluminum Powder with Enhanced Anticorrosive Properties

Science.gov (United States)

He, Lihua; Zhao, Yan; Xing, Liying; Liu, Pinggui; Wang, Zhiyong; Zhang, Youwei; Liu, Xiaofang

2017-07-01

To improve the anticorrosive performance of aluminum powder, a common functional filler in polymer coatings, we report a novel method to prepare graphene oxide modified aluminum powder (GO-Al) using 3-aminoproplyphosphoic acid as "link" agent. The GO nanosheets were firstly functionalized with 3-aminoproplyphosphoic acid (APSA) by the reaction of amine groups of APSA and the epoxy groups of GO. Subsequently, a layer of GO nanosheets uniformly and tightly covered the surface of flaky aluminum particle though the strong linking strength between -PO(OH)2 functional groups of the modified GO and aluminum. The hydrogen evolution experiment suggests that the GO attached on the aluminum powder could effectively improve the anticorrosive performance of the pigments.

Palladium catalyst system comprising zwitterion and/or acid-functionalized ionic liquid

DEFF Research Database (Denmark)

2011-01-01

The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3......COCHCOCH3), Pd (CF3COO)2, Pd(PPh3)4 or Pd2(dibenzylideneacetone)3. Such catalyst systems can be used for e.g. alkoxycarbonylation reactions, carboxylation reactions, and/or in a co-polymerization reaction, e.g. in the production of methyl propionate and/or propanoic acid, optionally in processes forming...... methyl methacrylate and/or methacrylic acid. Catalyst systems according to the invention are suitable for reactions forming separable product and catalyst phases and supported ionic liquid phase SILP applications....

Dietary fatty acids influence sperm quality and function.

Science.gov (United States)

Ferramosca, A; Moscatelli, N; Di Giacomo, M; Zara, V

2017-05-01

Recently, obesity has been linked to male infertility. In animal models the administration of a high-fat diet caused a reduction in sperm quality, by impairing gamete energy metabolism. The aim of this study was to investigate a possible effect of dietary fatty acids supplementation in the modulation of sperm energy metabolism and, in turn, in the improvement of sperm quality in rats fed a high-fat diet. Sexually mature male Sprague-Dawley rats were divided into four groups and fed for 4 weeks a standard diet (control group), a high-fat diet (enriched in 35% of fat and 15% sucrose), a high-fat diet supplemented with 2.5% olive oil (a source of monounsaturated fatty acids) or a high-fat diet supplemented with 2.5% krill oil (a source of n-3 polyunsaturated fatty acids). Liver and adipose tissue weight, plasma glucose, insulin and lipid concentrations were determined. Activities of enzymes involved in sperm energetic metabolism were evaluated by spectrophotometric assays. Sperm mitochondrial respiratory efficiency was also assayed. The obtained results suggest that olive oil partially counteracts the negative effects of a high-fat diet on sperm quality, by increasing gamete motility, by reducing oxidative stress and slightly improving mitochondrial respiration efficiency. On the other hand, krill oil determines an increase in sperm concentration and motility, an increase in the activities of lactate dehydrogenase, Krebs cycle enzymes and respiratory chain complexes; a parallel increase in the cellular levels of ATP and a reduction in oxidative damage were also observed. These results suggest that dietary fatty acids are able to positively influence sperm quality and function. © 2017 American Society of Andrology and European Academy of Andrology.

Interfacial characteristics of an epoxy composite reinforced with phosphoric acid-functionalized Kevlar fibers

Science.gov (United States)

Li, J.; Xia, Y. C.

2010-07-01

A Kevlar fiber was functionalized with the phosphoric acid (PA) of different concentrations. The surface characteristics of the fiber were examined by using the X-ray photoelectron spectroscopy. It was found that the PA functionalization considerably increased the bond strength between the Kevlar fiber and an epoxy matrix.

Amino Acid Profile, Group of Functional and Molecular Weight Distribution of Goat Skin Gelatin That Produced Through Acid Process

Directory of Open Access Journals (Sweden)

Muhammad Irfan Said

2012-02-01

Full Text Available Gelatin is a product of hydrolysis of collagen protein from animals that are partially processed.  Gelatin used in food and non food industries.  Gelatin is produced when many import of raw skins and bones of pigs and cows.  Goat skins potential as a raw material substitution that still doubt its halal. Process production of gelatin determine the properties of gelatin. The objectives of this research were to determine amino acid profile, group of functional and molecular weight distribution of gelatin made from goat skins which was produced through a process of acid. The skin of male Bligon goat, 1.5 to 2.5 year old was used as raw materials. Process production of gelatin was using acid type acetic acid (CH3COOH 0.5 M (v/v as curing material. The experimental design applied in this study and commercial gelatin was used as control. The results showed that gelatin produced from goat skin through the process of acid had properties identical with commercial gelatin. It can be concluded that the gelatin has the potential substitute product of commercial gelatin. Keywords: collagen, gelatin, goat skin, curing, acid process

Arachidonic acid and other unsaturated fatty acids and some of their metabolites function as endogenous antimicrobial molecules: A review

Directory of Open Access Journals (Sweden)

Undurti N. Das

2018-05-01

Full Text Available Our body is endowed with several endogenous anti-microbial compounds such as interferon, cytokines, free radicals, etc. However, little attention has been paid to the possibility that lipids could function as antimicrobial compounds. In this short review, the antimicrobial actions of various polyunsaturated fatty acids (PUFAs, mainly free acids and their putative mechanisms of action are described. In general, PUFAs kill microbes by their direct action on microbial cell membranes, enhancing generation of free radicals, augmenting the formation of lipid peroxides that are cytotoxic, and by increasing the formation of their bioactive metabolites, such as prostaglandins, lipoxins, resolvins, protectins and maresins that enhance the phagocytic action of leukocytes and macrophages. Higher intakes of α-linolenic and cis-linoleic acids (ALA and LA respectively and fish (a rich source of eicosapentaenoic acid and docosahexaenoic acid might reduce the risk pneumonia. Previously, it was suggested that polyunsaturated fatty acids (PUFAs: linoleic, α-linolenic, γ-linolenic (GLA, dihomo-GLA (DGLA, arachidonic (AA, eicosapentaenoic (EPA, and docosahexaenoic acids (DHA function as endogenous anti-bacterial, anti-fungal, anti-viral, anti-parasitic, and immunomodulating agents. A variety of bacteria are sensitive to the growth inhibitory actions of LA and ALA in vitro. Hydrolyzed linseed oil can kill methicillin-resistant Staphylococcus aureus. Both LA and AA have the ability to inactivate herpes, influenza, Sendai, and Sindbis virus within minutes of contact. AA, EPA, and DHA induce death of Plasmodium falciparum both in vitro and in vivo. Prostaglandin E1 (PGE1 and prostaglandin A (PGA, derived from DGLA, AA, and EPA inhibit viral replication and show anti-viral activity. Oral mucosa, epidermal cells, lymphocytes and macrophages contain and release significant amounts of PUFAs on stimulation. PUFAs stimulate NADPH-dependent superoxide production by

Effects of compound amino acids capsule on the immunological function of naval servicemen

Directory of Open Access Journals (Sweden)

Hai-zhong ZHONG

2012-01-01

Full Text Available Objective  To investigate the effects of the compound amino acids capsule on the immunological function of the naval servicemen during military activity. Methods  The subjects included 100 officers and soldiers, whose Modified Fatigue Rating Scale (MFIS scores were >21 points. The participants were randomly divided into two groups, namely, the amino acids capsule group and placebo group (n=50. Under the condition of military operations, either amino acids capsule (8 kinds of essential amino acids and 11 kinds of vitamins were contained or placebo capsule was given for 14 days continuously. The humoral immune indices, i.e., IgG, IgA, IgM, and complements C3 and C4, were measured with immunoturbidimetry. The percentage of peripheral blood CD subsets was measured using flow cytometry on the first day and 14th day. Results  The levels of IgG, IgM, and complement C3 in the capsule group were significantly higher on the 14th day than on the first day (P+CD4+ T lymphocytes and CD3－CD19+ B lymphocytes in the capsule group on the 14th day were higher than those on the first day, whereas the CD3－CD56+ NK lymphocytes decreased significantly (PConclusion  Compound amino acids capsule can improve the humoral and cellular immunological function of naval servicemen.

Adsorption of uranium ions by crosslinked polyester resin functionalized with acrylic acid from aqueous solutions

International Nuclear Information System (INIS)

Cemal Oezeroglu; Niluefer Metin

2012-01-01

In this paper, the crosslinked polyester resin containing acrylic acid functional groups was used for the adsorption of uranium ions from aqueous solutions. For this purpose, the crosslinked polyester resin of unsaturated polyester in styrene monomer (Polipol 353, Poliya) and acrylic acid as weight percentage at 80 and 20%, respectively was synthesized by using methyl ethyl ketone peroxide (MEKp, Butanox M60, Azo Nobel)-cobalt octoate initiator system. The adsorption of uranium ions on the sample (0.05 g copolymer and 5 mL of U(VI) solution were mixed) of the crosslinked polyester resin functionalized with acrylic acid was carried out in a batch reactor. The effects of adsorption parameters of the contact time, temperature, pH of solution and initial uranium(VI) concentration for U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid were investigated. The adsorption data obtained from experimental results depending on the initial U(VI) concentration were analyzed by the Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The adsorption capacity and free energy change were determined by using D-R isotherm. The obtained experimental adsorption data depending on temperature were evaluated to calculate the thermodynamic parameters of enthalpy (ΔH o ), entropy (ΔS o ) and free energy change (ΔG o ) for the U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid from aqueous solutions. The obtained adsorption data depending on contact time were analyzed by using adsorption models such as the modified Freundlich, Elovich, pseudo-first order and pseudo-second-order kinetic models. (author)

Xanthurenic acid translocates proapoptotic Bcl-2 family proteins into mitochondria and impairs mitochondrial function

Directory of Open Access Journals (Sweden)

Hess Otto M

2004-04-01

Full Text Available Abstract Background Xanthurenic acid is an endogenous molecule produced by tryptophan degradation, produced in the cytoplasm and mitochondria. Its accumulation can be observed in aging-related diseases, e.g. senile cataract and infectious disease. We previously reported that xanthurenic acid provokes apoptosis, and now present a study of the response of mitochondria to xanthurenic acid. Results Xanthurenic acid at 10 or 20 μM in culture media of human aortic smooth muscle cells induces translocation of the proteins Bax, Bak, Bclxs, and Bad into mitochondria. In 20 μM xanthurenic acid, Bax is also translocated to the nucleus. In isolated mitochondria xanthurenic acid leads to Bax and Bclxs oligomerization, accumulation of Ca2+, and increased oxygen consumption. Conclusion Xanthurenic acid interacts directly with Bcl-2 family proteins, inducing mitochondrial pathways of apoptosis and impairing mitochondrial functions.

Synthesis selective transport properties of cleft-type ionophores having two convergent hydroxamic acid functions

International Nuclear Information System (INIS)

Kim, Duck Hee; Choi, Mi Jung; Chang, Suk Kyu

2001-01-01

A series of cleft-type ionophores having two convergent hydroxamic acid functions are prepared and their selective ionophoric properties toward heavy metal and transition metal ions have been investigated. Hydroxamic acids 3 exhibited a prominent selectivity toward heavy metal ions of Hg 2+ and Pb 2+ , and transition metal ions of Cu 2+ over other transition metal and alkaline earth metal ions from slightly acidic source phase (pH 6) to an acidic receiving phase (pH 1). Selective ionophoric properties toward Pb 2+ and Cu 2+ ions over other surveyed metal ions are also confirmed by the FAB-MS measurements

Palladium catalyst system comprising zwitterion and/or acid-​functionalized ionic liquid

DEFF Research Database (Denmark)

2011-01-01

The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3...... methyl methacrylate and/or methacrylic acid. Catalyst systems according to the invention are suitable for reactions forming separable product and catalyst phases and supported ionic liquid phase SILP applications....

Dihydroazulene Photochromism:Synthesis, Molecular Electronics and Hammett Correlations

DEFF Research Database (Denmark)

Broman, Søren Lindbæk

This thesis describes the development of a versatile synthetic protocol for preparation of a large selection of dihydroazulenes (DHAs) with both electron withdrawing and donating groups. By UV-Vis and NMR spectroscopies and even in a single-molecule junction, their ability to undergo a light...... will be discussed in detail. The second chapter describes the design and synthesis of DHA/VHFs intended for use in molecular electronics and their solution and single-molecule junction switching properties. By the expansion of the recently reported procedure for functionalization of this system by Suzuki cross...

Amino Acid Functionalization of Doped Single-Walled Carbon Nanotubes: Effects of Dopants and Side Chains as Well as Zwitterionic Stabilizations.

Science.gov (United States)

Jiang, Lisha; Zhu, Chang; Fu, Yujie; Yang, Gang

2017-04-06

Functionalization of single-walled carbon nanotubes (SWCNTs) is necessitated in a number of conditions such as drug delivery, and here amino acid functionalization of SWCNTs is conducted within the framework of density functional theory. Functionalization efficiencies of Gly are largely determined by dopants, as a combined effect of atomic radius, electronic configuration, and distortion to SWCNTs. Different functionalization sites in Gly have divergent interaction strengths with M/SWCNTs that decline as O b > N > O a , and this trend seems almost independent of the identity of metallic dopants. B/SWCNT behaves distinctly and prefers to the N site. Dopants affect principally interaction strengths, while amino acids regulate significantly both functionalization configurations and interaction energies. Then focus is given to stabilization of zwitterionic amino acids due to enhanced interactions with the widely used zwitterionic drugs. All metallic dopants render zwitterionic Gly to be the most stable, and side chains in amino acids rather than dopants in M/SWCNTs cause more pronounced effects to zwitterionic stabilizations. Charge transfers between amino acids and M/SWCNTs are closely associated with zwitterionic stabilization effects, and different charge transfer mechanisms between M/SWCNTs and metal ions are interpreted. Thus, this work provides a comprehensive understanding of amino acid functionalization of M/SWCNTs.

Observing trends in the functionalization of cnts using same oxidizing acids under two different conditions

International Nuclear Information System (INIS)

Aftab, S.

2013-01-01

Excellent electrical, mechanical, optical and thermal properties are attributed to carbon nanotubes. Carbon nanotubes need to be functionalized to form a homogeneous dispersion. In this work, catalytically produced carbon nanotubes have been functionalized under two different conditions using the same acid medium. The effect of the two reaction routes on the carbon nanotubes, in terms of the extent of covalent functionalization has been determined by several techniques. Scanning electron microscopy aided in the observation of their morphology and X-ray diffraction was used to ascertain their structure. Other analytical characterization tools employed were Fourier transform infrared spectroscopy, Zeta potential measurement, UV spectroscopy, Oxygen percentage analysis, Boehm's titration and visual dispersion. Results show that carbon nanotubes functionalized by refluxing in the acids are much better dispersed. (author)

Dietary supplementation with an amino acid blend enhances intestinal function in piglets.

Science.gov (United States)

Yi, Dan; Li, Baocheng; Hou, Yongqing; Wang, Lei; Zhao, Di; Chen, Hongbo; Wu, Tao; Zhou, Ying; Ding, Binying; Wu, Guoyao

2018-05-16

The traditionally classified nutritionally non-essential amino acids are now known to be insufficiently synthesized for maximal growth and optimal health in piglets. This study determined the effects of dietary supplementation with an amino acid blend (AAB; glutamate:glutamine:glycine:arginine:N-acetylcysteine = 5:2:2:1:0.5) on piglet growth performance and intestinal functions. Sixteen piglets (24-day-old) were randomly assigned to a corn and soybean meal-based diet supplemented with 0.99% alanine (isonitrogenous control) or 1% AAB. On day 20 of the trial, blood and intestinal tissue samples were obtained from piglets. Compared with the control, AAB supplementation reduced (P sodium-independent amino acid transporters (b 0,+ AT and y + LAT1), aquaporin (AQP) 3, AQP8, AQP10, nuclear factor erythroid 2-related factor 2 and glutathione S-transferase omega-2, and protein abundances of AQP3, AQP4, claudin-1, occludin and myxovirus resistance 1; and the numbers of Bifidobacterium genus and Lactobacillus genus in the colon digesta. Collectively, these comprehensive results indicate that dietary AAB supplementation plays an important role in improving piglet growth and intestinal function.

Predicting taxonomic and functional structure of microbial communities in acid mine drainage.

Science.gov (United States)

Kuang, Jialiang; Huang, Linan; He, Zhili; Chen, Linxing; Hua, Zhengshuang; Jia, Pu; Li, Shengjin; Liu, Jun; Li, Jintian; Zhou, Jizhong; Shu, Wensheng

2016-06-01

Predicting the dynamics of community composition and functional attributes responding to environmental changes is an essential goal in community ecology but remains a major challenge, particularly in microbial ecology. Here, by targeting a model system with low species richness, we explore the spatial distribution of taxonomic and functional structure of 40 acid mine drainage (AMD) microbial communities across Southeast China profiled by 16S ribosomal RNA pyrosequencing and a comprehensive microarray (GeoChip). Similar environmentally dependent patterns of dominant microbial lineages and key functional genes were observed regardless of the large-scale geographical isolation. Functional and phylogenetic β-diversities were significantly correlated, whereas functional metabolic potentials were strongly influenced by environmental conditions and community taxonomic structure. Using advanced modeling approaches based on artificial neural networks, we successfully predicted the taxonomic and functional dynamics with significantly higher prediction accuracies of metabolic potentials (average Bray-Curtis similarity 87.8) as compared with relative microbial abundances (similarity 66.8), implying that natural AMD microbial assemblages may be better predicted at the functional genes level rather than at taxonomic level. Furthermore, relative metabolic potentials of genes involved in many key ecological functions (for example, nitrogen and phosphate utilization, metals resistance and stress response) were extrapolated to increase under more acidic and metal-rich conditions, indicating a critical strategy of stress adaptation in these extraordinary communities. Collectively, our findings indicate that natural selection rather than geographic distance has a more crucial role in shaping the taxonomic and functional patterns of AMD microbial community that readily predicted by modeling methods and suggest that the model-based approach is essential to better understand natural

Using analyses of amino Acid coevolution to understand protein structure and function.

Science.gov (United States)

Ashenberg, Orr; Laub, Michael T

2013-01-01

Determining which residues of a protein contribute to a specific function is a difficult problem. Analyses of amino acid covariation within a protein family can serve as a useful guide by identifying residues that are functionally coupled. Covariation analyses have been successfully used on several different protein families to identify residues that work together to promote folding, enable protein-protein interactions, or contribute to an enzymatic activity. Covariation is a statistical signal that can be measured in a multiple sequence alignment of homologous proteins. As sequence databases have expanded dramatically, covariation analyses have become easier and more powerful. In this chapter, we describe how functional covariation arises during the evolution of proteins and how this signal can be distinguished from various background signals. We discuss the basic methodology for performing amino acid covariation analysis, using bacterial two-component signal transduction proteins as an example. We provide practical suggestions for each step of the process including assembly of protein sequences, construction of a multiple sequence alignment, measurement of covariation, and analysis of results. Copyright © 2013 Elsevier Inc. All rights reserved.

Facile fabrication of siloxane @ poly (methylacrylic acid) core-shell microparticles with different functional groups

Energy Technology Data Exchange (ETDEWEB)

Zhao, Zheng-Bai; Tai, Li; Zhang, Da-Ming; Jiang, Yong, E-mail: yj@seu.edu.cn [Southeast University, School of Chemistry and Chemical Engineering (China)

2017-02-15

Siloxane @ poly (methylacrylic acid) core-shell microparticles with functional groups were prepared by a facile hydrolysis-condensation method in this work. Three different silane coupling agents 3-methacryloxypropyltrimethoxysilane (MPS), 3-triethoxysilylpropylamine (APTES), and 3-glycidoxypropyltrimethoxysilane (GPTMS) were added along with tetraethoxysilane (TEOS) into the polymethylacrylic acid (PMAA) microparticle ethanol dispersion to form the Si@PMAA core-shell microparticles with different functional groups. The core-shell structure and the surface special functional groups of the resulting microparticles were measured by transmission electron microscopy and FTIR. The sizes of these core-shell microparticles were about 350–400 nm. The corresponding preparation conditions and mechanism were discussed in detail. This hydrolysis-condensation method also could be used to functionalize other microparticles which contain active groups on the surface. Meanwhile, the Si@PMAA core-shell microparticles with carbon-carbon double bonds and amino groups have further been applied to prepare hydrophobic coatings.

Facile fabrication of siloxane @ poly (methylacrylic acid) core-shell microparticles with different functional groups

International Nuclear Information System (INIS)

Zhao, Zheng-Bai; Tai, Li; Zhang, Da-Ming; Jiang, Yong

2017-01-01

Siloxane @ poly (methylacrylic acid) core-shell microparticles with functional groups were prepared by a facile hydrolysis-condensation method in this work. Three different silane coupling agents 3-methacryloxypropyltrimethoxysilane (MPS), 3-triethoxysilylpropylamine (APTES), and 3-glycidoxypropyltrimethoxysilane (GPTMS) were added along with tetraethoxysilane (TEOS) into the polymethylacrylic acid (PMAA) microparticle ethanol dispersion to form the Si@PMAA core-shell microparticles with different functional groups. The core-shell structure and the surface special functional groups of the resulting microparticles were measured by transmission electron microscopy and FTIR. The sizes of these core-shell microparticles were about 350–400 nm. The corresponding preparation conditions and mechanism were discussed in detail. This hydrolysis-condensation method also could be used to functionalize other microparticles which contain active groups on the surface. Meanwhile, the Si@PMAA core-shell microparticles with carbon-carbon double bonds and amino groups have further been applied to prepare hydrophobic coatings.

Effects of Different Solvents on the Surface Acidic Oxygen-containing Functional Groups on Xanthoceras sorbifolia Shell

Directory of Open Access Journals (Sweden)

Linan Liu

2014-03-01

Full Text Available This study reports the preparation of a novel biomaterial from a forestry residue - Xanthoceras sorbifolia shell (XSS - by solvent modification. The effects of acid and base (hydrochloric acerbic, acetic acid, sodium hydroxide, ammonia water and some organic solvents (ethanol, acetone, ethyl acetate, chloroform, petroleum ether, and n-hexane on the surface acidic functional groups (SAFGs on XSS were investigated. The amount of SAFGs was quantified using acid and alkali chemical titration methods, and the characteristics of virgin XSS were compared with treated ones by FT-IR spectroscopy. It was found that acid solutions can increase the concentration of SAFGs, while alkaline solutions reduce it. The XSS treated in 0.5 M HCl has the largest number of total acidic functional groups and phenolic hydroxyl groups. The shell extracted with 2 M acetic acid has the highest concentration of carboxyl. The SAFG contents were remarkably increased by treatments with ethanol and acetone, due to the outstanding enhancement of phenolic hydroxyl. These changes in the SAFGs of XSS brought about by treatments with various solutions could be a theoretical foundation for modifying this residue to create a new type of highly efficient absorbent material.

Functional characterization of two microsomal fatty acid desaturases from Jatropha curcas L.

Science.gov (United States)

Wu, Pingzhi; Zhang, Sheng; Zhang, Lin; Chen, Yaping; Li, Meiru; Jiang, Huawu; Wu, Guojiang

2013-10-15

Linoleic acid (LA, C18:2) and α-linolenic acid (ALA, C18:3) are polyunsaturated fatty acids (PUFAs) and major storage compounds in plant seed oils. Microsomal ω-6 and ω-3 fatty acid (FA) desaturases catalyze the synthesis of seed oil LA and ALA, respectively. Jatropha curcas L. seed oils contain large proportions of LA, but very little ALA. In this study, two microsomal desaturase genes, named JcFAD2 and JcFAD3, were isolated from J. curcas. Both deduced amino acid sequences possessed eight histidines shown to be essential for desaturases activity, and contained motif in the C-terminal for endoplasmic reticulum localization. Heterologous expression in Saccharomyces cerevisiae and Arabidopsis thaliana confirmed that the isolated JcFAD2 and JcFAD3 proteins could catalyze LA and ALA synthesis, respectively. The results indicate that JcFAD2 and JcFAD3 are functional in controlling PUFA contents of seed oils and could be exploited in the genetic engineering of J. curcas, and potentially other plants. Copyright © 2013 Elsevier GmbH. All rights reserved.

Catalytic transformation of functionalized carboxylic acids using multifunctional rhenium complexes.

Science.gov (United States)

Naruto, Masayuki; Agrawal, Santosh; Toda, Katsuaki; Saito, Susumu

2017-06-13

Carboxylic acids (CAs) are one of the most ubiquitous and important chemical feedstocks available from biorenewable resources, CO 2 , and the petrochemical industry. Unfortunately, chemoselective catalytic transformations of CH n CO 2 H (n = 1-3) groups into other functionalities remain a significant challenge. Herein, we report rhenium V complexes as extremely effective precatalysts for this purpose. Compared to previously reported heterogeneous and homogeneous catalysts derived from high- or low-valent metals, the present method involves a α-C-H bond functionalization, a hydrogenation, and a hydrogenolysis, which affords functionalized alcohols with a wide substrate scope and high chemoselectivity under relatively mild reaction conditions. The results represent an important step toward a paradigm shift from 'low-valent' to 'high-valent' metal complexes by exploring a new portfolio of selective functional group transformations of highly oxygenated organic substrates, as well as toward the exploitation of CAs as a valuable biorenewable feedstock.

A proteomic analysis of the functional effects of fatty acids in NIH 3T3 fibroblasts

LENUS (Irish Health Repository)

Magdalon, Juliana

2011-11-24

Abstract Previous studies have demonstrated that long chain fatty acids influence fibroblast function at sub-lethal concentrations. This study is the first to assess the effects of oleic, linoleic or palmitic acids on protein expression of fibroblasts, as determined by standard proteomic techniques. The fatty acids were not cytotoxic at the concentration used in this work as assessed by membrane integrity, DNA fragmentation and the MTT assay but significantly increased cell proliferation. Subsequently, a proteomic analysis was performed using two dimensional difference gel electrophoresis (2D-DIGE) and MS based identification. Cells treated with 50 μM oleic, linoleic or palmitic acid for 24 h were associated with 24, 22, 16 spots differentially expressed, respectively. Among the identified proteins, α-enolase and far upstream element binding protein 1 (FBP-1) are of importance due to their function in fibroblast-associated diseases. However, modulation of α-enolase and FBP-1 expression by fatty acids was not validated by the Western blot technique.

Conjugated linoleic acids as functional food: an insight into their health benefits

Directory of Open Access Journals (Sweden)

Benjamin Sailas

2009-09-01

Full Text Available Abstract This review evaluates the health benefits of the functional food, conjugated linoleic acids (CLA - a heterogeneous group of positional and geometric isomers of linoleic acid predominantly found in milk, milk products, meat and meat products of ruminants. During the past couple of decades, hundreds of reports - principally based on in vitro, microbial, animal, and of late clinical trials on humans - have been accumulating with varying biological activities of CLA isomers. These studies highlight that CLA, apart form the classical nuclear transcription factors-mediated mechanism of action, appear to exhibit a number of inter-dependent molecular signalling pathways accounting for their reported health benefits. Such benefits relate to anti-obesitic, anti-carcinogenic, anti-atherogenic, anti-diabetagenic, immunomodulatory, apoptotic and osteosynthetic effects. On the other hand, negative effects of CLA have been reported such as fatty liver and spleen, induction of colon carcinogenesis and hyperproinsulinaemia. As far as human consumption is concerned, a definite conclusion for CLA safety has not been reached yet. Parameters such as administration of the type of CLA isomer and/or their combination with other polyunsaturated fatty acids, mode of administration (eg., as free fatty acid or its triglyceride form, liquid or solid, daily dose and duration of consumption, gender, age, or ethnic and geographical backgrounds remain to be determined. Yet, it appears from trials so far conducted that CLA are functional food having prevailing beneficial health effects for humans.

Cardiomyocyte Triglyceride Accumulation and Reduced Ventricular Function in Mice with Obesity Reflect Increased Long Chain Fatty Acid Uptake and De Novo Fatty Acid Synthesis

Directory of Open Access Journals (Sweden)

Fengxia Ge

2012-01-01

Full Text Available A nonarteriosclerotic cardiomyopathy is increasingly seen in obese patients. Seeking a rodent model, we studied cardiac histology, function, cardiomyocyte fatty acid uptake, and transporter gene expression in male C57BL/6J control mice and three obesity groups: similar mice fed a high-fat diet (HFD and db/db and ob/ob mice. At sacrifice, all obesity groups had increased body and heart weights and fatty livers. By echocardiography, ejection fraction (EF and fractional shortening (FS of left ventricular diameter during systole were significantly reduced. The Vmax for saturable fatty acid uptake was increased and significantly correlated with cardiac triglycerides and insulin concentrations. Vmax also correlated with expression of genes for the cardiac fatty acid transporters Cd36 and Slc27a1. Genes for de novo fatty acid synthesis (Fasn, Scd1 were also upregulated. Ten oxidative phosphorylation pathway genes were downregulated, suggesting that a decrease in cardiomyocyte ATP synthesis might explain the decreased contractile function in obese hearts.

Pd nanoparticles supported on functionalized multi-walled carbon nanotubes (MWCNTs) and electrooxidation for formic acid

Energy Technology Data Exchange (ETDEWEB)

Yang, Sudong; Mi, Hongyu; Ye, Xiangguo [Institute of Applied Chemistry, Xinjiang University, Urumqi 830046 (China); Zhang, Xiaogang [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

2008-01-03

To improve the utilization and activity of anodic catalysts for formic acid electrooxidation, palladium (Pd) particles were loaded on the MWCNTs, which were functionalized in a mixture of 96% sulfuric acid and 4-aminobenzenesulfonic acid, using sodium nitrite to produce intermediate diazonium salts from substituted anilines. The composition, particle size, and crystallinity of the Pd/f-MWCNTs catalysts were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) measurements. The electrocatalytic properties of the Pd/f-MWCNTs catalysts for formic acid oxidation were investigated by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) in 0.5 mol L{sup -1} H{sub 2}SO{sub 4} solution. The results demonstrated that the catalytic activity was greatly enhanced due to the improved water-solubility and dispersion of the f-MWCNTs, which were facile to make the small particle size (3.8 nm) and uniform dispersion of Pd particles loading on the surface of the MWCNTs. In addition, the functionalized MWCNTs with benzenesulfonic group can provide benzenesulfonic anions in aqueous solution, which may combine with hydrogen cation and then promote the oxidation of formic acid reactive intermediates. So the Pd/f-MWCNTs composites showed excellent electrocatalytic activity for formic acid oxidation. (author)

ImprimatinC1, a novel plant immune-priming compound, functions as a partial agonist of salicylic acid.

Science.gov (United States)

Noutoshi, Yoshiteru; Jikumaru, Yusuke; Kamiya, Yuji; Shirasu, Ken

2012-01-01

Plant activators are agrochemicals that protect crops from pathogens. They confer durable resistance to a broad range of diseases by activating intrinsic immune mechanisms in plants. To obtain leads regarding useful compounds, we have screened a chemical library using an established method that allows selective identification of immune-priming compounds. Here, we report the characterisation of one of the isolated chemicals, imprimatinC1, and its structural derivative imprimatinC2. ImprimatinC1 functions as a weak analogue of salicylic acid (SA) and activates the expression of defence-related genes. However, it lacks antagonistic activity toward jasmonic acid. Structure-activity relationship analysis suggests that imprimatinC1 and C2 can be metabolised to 4-chlorobenzoic acid and 3,4-chlorobenzoic acid, respectively, to function in Arabidopsis. We also found that imprimatinC1 and C2 and their potential functional metabolites acted as partial agonists of SA. Thus, imprimatinC compounds could be useful tools for dissecting SA-dependent signal transduction pathways.

Acid-sensing ion channels: trafficking and synaptic function

Directory of Open Access Journals (Sweden)

Zha Xiang-ming

2013-01-01

Full Text Available Abstract Extracellular acidification occurs in the brain with elevated neural activity, increased metabolism, and neuronal injury. This reduction in pH can have profound effects on brain function because pH regulates essentially every single biochemical reaction. Therefore, it is not surprising to see that Nature evolves a family of proteins, the acid-sensing ion channels (ASICs, to sense extracellular pH reduction. ASICs are proton-gated cation channels that are mainly expressed in the nervous system. In recent years, a growing body of literature has shown that acidosis, through activating ASICs, contributes to multiple diseases, including ischemia, multiple sclerosis, and seizures. In addition, ASICs play a key role in fear and anxiety related psychiatric disorders. Several recent reviews have summarized the importance and therapeutic potential of ASICs in neurological diseases, as well as the structure-function relationship of ASICs. However, there is little focused coverage on either the basic biology of ASICs or their contribution to neural plasticity. This review will center on these topics, with an emphasis on the synaptic role of ASICs and molecular mechanisms regulating the spatial distribution and function of these ion channels.

Acid-sensing ion channels: trafficking and synaptic function.

Science.gov (United States)

Zha, Xiang-ming

2013-01-02

Extracellular acidification occurs in the brain with elevated neural activity, increased metabolism, and neuronal injury. This reduction in pH can have profound effects on brain function because pH regulates essentially every single biochemical reaction. Therefore, it is not surprising to see that Nature evolves a family of proteins, the acid-sensing ion channels (ASICs), to sense extracellular pH reduction. ASICs are proton-gated cation channels that are mainly expressed in the nervous system. In recent years, a growing body of literature has shown that acidosis, through activating ASICs, contributes to multiple diseases, including ischemia, multiple sclerosis, and seizures. In addition, ASICs play a key role in fear and anxiety related psychiatric disorders. Several recent reviews have summarized the importance and therapeutic potential of ASICs in neurological diseases, as well as the structure-function relationship of ASICs. However, there is little focused coverage on either the basic biology of ASICs or their contribution to neural plasticity. This review will center on these topics, with an emphasis on the synaptic role of ASICs and molecular mechanisms regulating the spatial distribution and function of these ion channels.

Amino-Functional Polybenzimidazole Blends with Enhanced Phosphoric Acid Mediated Proton Conductivity as Fuel Cell Electrolytes

DEFF Research Database (Denmark)

Aili, David; Javakhishvili, Irakli; Han, Junyoung

2016-01-01

A new amino-functional polybenzimidazole copolymer is synthesized by homogeneous solution condensation polymerization from a novel monomer, N,N′-bis (2,4-diaminophenyl)-1,3-diaminopropane. The copolymer readily dissolves in organic solvents and shows good film forming characteristics. To balance...... the phosphoric acid uptake and to obtain mechanically robust membranes, the amino-functional polybenzimidazole derivative is blended with high molecular weight poly [2,2′-(m-phenylene)-5,5′-bisbenzimidazole] at different ratios. Due to the high acid uptake, the homogenous blend membranes show enhanced proton...

Diversity and functional properties of acid-tolerant bacteria isolated from tea plantation soil of Assam.

Science.gov (United States)

Goswami, Gunajit; Deka, Priyadarshini; Das, Pompi; Bora, Sudipta Sankar; Samanta, Ramkrishna; Boro, Robin Chandra; Barooah, Madhumita

2017-07-01

In this study, we report on the bacterial diversity and their functional properties prevalent in tea garden soils of Assam that have low pH (3.8-5.5). Culture-dependent studies and phospholipid fatty acid analysis revealed a high abundance of Gram-positive bacteria. Further, 70 acid-tolerant bacterial isolates characterized using a polyphasic taxonomy approach could be grouped to the genus Bacillus, Lysinibacillus, Staphylococcus, Brevundimonas, Alcaligenes, Enterobacter, Klebsiella, Escherichia, and Aeromonas. Among the 70 isolates, 47 most promising isolates were tested for their plant growth promoting activity based on the production of Indole Acetic Acid (IAA), siderophore, and HCN as well as solubilization of phosphate, zinc, and potassium. Out of the 47 isolates, 10 isolates tested positive for the entire aforesaid plant growth promoting tests and further tested for quantitative analyses for production of IAA, siderophore, and phosphate solubilization at the acidic and neutral condition. Results indicated that IAA and siderophore production, as well as phosphate solubilization efficiency of the isolates decreased significantly (P ≤ 0.05) in the acidic environment. This study revealed that low soil pH influences bacterial community structure and their functional properties.

Neural Correlates of Visual-Spatial Attention in Electrocorticographic Signals in Humans

Science.gov (United States)

2011-09-23

PEST) procedure (Taylor and Creelman , 1967; Hammett and Snowden, 1995) that was run at the beginning of the session. The PEST procedure selected the...Medical Publishers, Inc. Taylor, M. M., and Creelman , C. D. (1967). PEST: efficient estimates on probabil- ity functions. J. Acoust. Soc. Am. 41

Overall renal and tubular function during infusion of amino acids in normal man

DEFF Research Database (Denmark)

Olsen, Niels Vidiendal; Hansen, J M; Ladefoged, S D

1990-01-01

sodium concentration] increased by 40% (P less than 0.001). Plasma renin concentration did not change significantly. 4. The results suggest that amino acids increase GFR by a primary effect on renal haemodynamics or, less likely, by reducing the signal to the tubuloglomerular feedback mechanism......1. Amino acids have been used to test renal reserve filtration capacity. Previous studies suggest that amino acids increase glomerular filtration rate (GFR) by reducing distal tubular flow and tubuloglomerular feedback activity. 2. Glomerular function and the renal tubular handling of sodium during...... infusion of amino acids was studied in 12 normal volunteers. 3. Clearance of sodium (CNa) was unchanged. Effective renal plasma flow increased slightly, but significantly, by 9% (P less than 0.05). GFR was increased by 13% (P less than 0.001). Clearance of lithium (CLi) (used as an index of proximal...

High serum uric acid levels are a protective factor against unfavourable neurological functional outcome in patients with ischaemic stroke.

Science.gov (United States)

Wang, Yu-Fang; Li, Jiao-Xing; Sun, Xun-Sha; Lai, Rong; Sheng, Wen-Li

2018-05-01

Objective We aimed to evaluate the association between serum uric acid levels at the onset and prognostic outcome in patients with acute ischaemic stroke. Methods We retrospectively analysed the outcomes of 1166 patients with ischaemic stroke who were hospitalized in our centre during August 2008 to November 2012. Correlations of serum uric acid levels and prognostic outcomes were analysed. Results Men had higher serum uric acid levels and better neurological functional outcomes compared with women. There was a strong negative correlation between serum uric acid levels and unfavourable neurological functional outcomes. Generalized estimated equation analysis showed that a higher serum uric acid level (>237 µmol/L) was a protective factor for neurological functional outcome in male, but not female, patients. Among five trial of ORG 10172 in acute stroke treatment classification subtypes, only patients with the large-artery atherosclerosis subtype had a significant protective effect of serum uric acid levels on neurological outcome. Conclusions Our study shows that high serum uric acid levels are a significant protective factor in men and in the large-artery atherosclerosis subtype in patients with ischaemic stroke. This is helpful for determining the prognostic value of serum uric acid levels for neurological outcome of acute ischaemic stroke.

Ethylenediamine-functionalized graphene oxide incorporated acid-base ion exchange membranes for vanadium redox flow battery

International Nuclear Information System (INIS)

Liu, Shuai; Li, Dan; Wang, Lihua; Yang, Haijun; Han, Xutong; Liu, Biqian

2017-01-01

Highlights: • Ethylenediamine functionalized graphene oxide. • Layered structure of functionalized graphene oxide block vanadium ions crossover. • Protonated N-containing groups suppress vanadium ions permeation. • Ion transport channels are narrowed by electrostatic interactions. • Vanadium crossover decreased due to enhanced Donnan effect and special structure. - Abstract: As a promising large-scale energy storage battery, vanadium redox flow battery (VRFB) is urgently needed to develop cost-effective membranes with excellent performance. Novel acid-base ion exchange membranes (IEMs) are fabricated based on sulfonated poly(ether ether ketone) (SPEEK) matrix and modified graphene oxide (GO) by solution blending. N-based functionalized graphene oxide (GO-NH 2 ) is fabricated by grafting ethylenediamine onto the edge of GO via a facile method. On one hand, the impermeable layered structures effectively block ion transport pathway to restrain vanadium ions crossover. On the other hand, acid-base pairs form between −SO 3 − groups and N-based groups on the edge of GO nanosheets, which not only suppress vanadium ions contamination but also provide a narrow pathway for proton migration. The structure is beneficial for achieving an intrinsic balance between conductivity and permeability. By altering amounts of GO-NH 2 , a sequence of acid-base IEMs are characterized in detail. The single cells assembled with acid-base IEMs show self-discharge time for 160 h, capacity retention 92% after 100 cycle, coulombic efficiency 97.2% and energy efficiency 89.5%. All data indicate that acid-base IEMs have promising prospects for VRFB applications.

Saponification of esters of chiral alpha-amino acids anchored through their amine function on solid support.

Science.gov (United States)

Cantel, Sonia; Desgranges, Stéphane; Martinez, Jean; Fehrentz, Jean-Alain

2004-06-01

Anchoring an alpha-amino acid residue by its amine function onto a solid support is an alternative to develop chemistry on its carboxylic function. This strategy can involve the use of amino-acid esters as precursors of the carboxylic function. A complete study on the Wang-resin was performed to determine the non racemizing saponification conditions of anchored alpha-amino esters. The use of LiOH, NaOH, NaOSi(Me)3, various solvents and temperatures were tested for this reaction. After saponification and cleavage from the support, samples were examined through their Marfey's derivatives by reversed phase HPLC to evaluate the percentage of racemization.

Acid- and base-catalysis in the mononuclear rearrangement of some (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole in toluene: effect of substituents on the course of reaction.

Science.gov (United States)

D'Anna, Francesca; Frenna, Vincenzo; Ghelfi, Franco; Marullo, Salvatore; Spinelli, Domenico

2011-04-15

The reaction rates for the rearrangement of eleven (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole 3a-k into the relevant (2-aryl-5-phenyl-2H-1,2,3-triazol-4-yl)ureas 4a-k in the presence of trichloroacetic acid or of piperidine have been determined in toluene at 313.1 K. The results have been related to the effect of the aryl substituent by using Hammett and/or Ingold-Yukawa-Tsuno correlations and have been compared with those previously collected in a protic polar solvent (dioxane/water) as well as with those on the analogous rearrangement of the corresponding (Z)-arylhydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazole 1a-k in benzene. Some light can thus be shed on the general differences of chemical reactivity between protic polar (or dipolar aprotic) and apolar solvents.

Molecular acidity: An accurate description with information-theoretic approach in density functional reactivity theory.

Science.gov (United States)

Cao, Xiaofang; Rong, Chunying; Zhong, Aiguo; Lu, Tian; Liu, Shubin

2018-01-15

Molecular acidity is one of the important physiochemical properties of a molecular system, yet its accurate calculation and prediction are still an unresolved problem in the literature. In this work, we propose to make use of the quantities from the information-theoretic (IT) approach in density functional reactivity theory and provide an accurate description of molecular acidity from a completely new perspective. To illustrate our point, five different categories of acidic series, singly and doubly substituted benzoic acids, singly substituted benzenesulfinic acids, benzeneseleninic acids, phenols, and alkyl carboxylic acids, have been thoroughly examined. We show that using IT quantities such as Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy, information gain, Onicescu information energy, and relative Rényi entropy, one is able to simultaneously predict experimental pKa values of these different categories of compounds. Because of the universality of the quantities employed in this work, which are all density dependent, our approach should be general and be applicable to other systems as well. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Carboxylic acid functionalization of halloysite nanotubes for sustained release of diphenhydramine hydrochloride

Energy Technology Data Exchange (ETDEWEB)

Zargarian, S. Sh.; Haddadi-Asl, V., E-mail: haddadi@aut.ac.ir; Hematpour, H. [Amirkabir University of Technology, Department of Polymer Engineering and Color Technology (Iran, Islamic Republic of)

2015-05-15

Halloysite nanotubes (HNT) (cylindrical shape with external diameter and length in the range of 30–80 nm and 0.2–1 µm, respectively) were functionalized with 3-aminopropyltriethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, maleic anhydride was attached to the APTES moieties to yield carboxylic acid-functionalized HNT. Loading and subsequent release of a model drug molecule diphenhydramine hydrochloride (DPH) on modified and unmodified nanotubes were investigated. Morphology of HNT was studied by electron microscopy. Successful attachment of APTES and carboxylic acid groups to halloysite and drug loading were evaluated by Fourier transform infrared spectroscopy. The amount of surface modification and drug adsorption capacity were calculated via thermogravimetric analysis. The ordered crystal structure of loaded drug was evaluated by X-ray diffraction. UV–Visible spectrophotometer was used to study drug release from modified and unmodified samples. Carboxylated halloysite exhibits higher loading capacity and prolonged release of DPH as compared to that of the natural halloysite.

Carboxylic acid functionalization of halloysite nanotubes for sustained release of diphenhydramine hydrochloride

International Nuclear Information System (INIS)

Zargarian, S. Sh.; Haddadi-Asl, V.; Hematpour, H.

2015-01-01

Halloysite nanotubes (HNT) (cylindrical shape with external diameter and length in the range of 30–80 nm and 0.2–1 µm, respectively) were functionalized with 3-aminopropyltriethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, maleic anhydride was attached to the APTES moieties to yield carboxylic acid-functionalized HNT. Loading and subsequent release of a model drug molecule diphenhydramine hydrochloride (DPH) on modified and unmodified nanotubes were investigated. Morphology of HNT was studied by electron microscopy. Successful attachment of APTES and carboxylic acid groups to halloysite and drug loading were evaluated by Fourier transform infrared spectroscopy. The amount of surface modification and drug adsorption capacity were calculated via thermogravimetric analysis. The ordered crystal structure of loaded drug was evaluated by X-ray diffraction. UV–Visible spectrophotometer was used to study drug release from modified and unmodified samples. Carboxylated halloysite exhibits higher loading capacity and prolonged release of DPH as compared to that of the natural halloysite

Acidic surface functional groups and mineral elements in Lakra coal (Sindh, Pakistan)

International Nuclear Information System (INIS)

Saeed, K.; Ishaq, M.; Ahjmad, I.; Shakirullah, M.; Haider, S.

2010-01-01

Surface acidity of virgin coal (Lakra Sindh, Pakistan) and variously extracted/leached coal samples with HNO/sub 3/ NaOH, and KMnO/sub 4/, were investigated by aqueous potentiometric titration employing KOH as a titrant. The titration curve of virgin coal showed that its surface might contain carboxylic, carbonyl, phenolic and other weak acidic functional groups such as enols and C-H bond. The titration curves of leached coal samples showed inflections at pH 4-11, being not similar the inflections of carboxylic groups. This inflection might be given by functional groups like CO/sub 2/, phenolic, enols and C-H. Mineral matter such as Fe, K, Zn, Mn and Ni were determined in the ash of coal by atomic absorption spectrophotometer and was found that Fe (3104 micro g/g) in the highest and Ni (36.05 micro g/g) in the lowest quantity is present in virgin coal sample. (author)

Boronic Acid functionalized core-shell polymer nanoparticles prepared by distillation precipitation polymerization for glycopeptide enrichment.

Science.gov (United States)

Qu, Yanyan; Liu, Jianxi; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

2012-07-16

The boronic acid-functionalized core-shell polymer nanoparticles, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@4-vinylphenylboronic acid (poly(MBA-co-MAA)@VPBA), were successfully synthesized for enriching glycosylated peptides. Such nanoparticles were composed of a hydrophilic polymer core prepared by distillation precipitation polymerization (DPP) and a boronic acid-functionalized shell designed for capturing glycopeptides. Owing to the relatively large amount of residual vinyl groups introduced by DPP on the core surface, the VPBA monomer was coated with high efficiency, working as the shell. Moreover, the overall polymerization route, especially the use of DPP, made the synthesis of nanoparticles facile and time-saving. With the poly(MBA-co-MAA)@VPBA nanoparticles, 18 glycopeptides from horseradish peroxidase (HRP) digest were captured and identified by MALDI-TOF mass spectrometric analysis, relative to eight glycopeptides enriched by using commercially available meta-aminophenylboronic acid agarose under the same conditions. When the concentration of the HRP digest was decreased to as low as 5 nmol, glycopeptides could still be selectively isolated by the prepared nanoparticles. Our results demonstrated that the synthetic poly(MBA-co-MAA)@VPBA nanoparticles might be a promising selective enrichment material for glycoproteome analysis. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Functional Foods Enriched with Marine Microalga Nannochloropsis oculata as a Source of ω-3 Fatty Acids

Directory of Open Access Journals (Sweden)

Srinivasan Babuskin

2014-01-01

Full Text Available The demand for functional food incorporated with ω-3 fatty acids is increasing over the years due to their added health benefits, such as reducing the risk of cardiovascular diseases, type II diabetes, ocular diseases, arthritis, etc. This study mainly aims to develop functional cookies and pasta enriched with ω-3 fatty acids. Nannochloropsis oculata was used because of its relatively high growth rate, high lipid content, resistance to mixing and contamination together with high nutritional values. The effect of the incorporation of Nannochloropsis oculata biomass on colour, firmness, fatty acid profile and sensory characteristics of cookies and pasta were evaluated. The colour values were found to be stable for two months of storage and the firmness increased with the addition of microalgal biomass. Omega-3 polyunsaturated fatty acid (PUFA levels (eicosapentaenoic and docosahexaenoic acids of 98 mg per 100 g and 63 mg per 100 g were observed in cookies and pasta, respectively, enriched with 1 % of Nannochloropsis oculata biomass. Sensory evaluation showed that the addition of up to 2 and 3 % of microalgal biomass was positively evaluated and accepted for cookies and pasta, respectively. This study confirms that the cookies and pasta enriched with Nannochloropsis oculata biomass might be used as a potential source of ω-3 fatty acids.

Quantitative structure-activity relationship analysis of substituted arylazo pyridone dyes in photocatalytic system: Experimental and theoretical study

Energy Technology Data Exchange (ETDEWEB)

Dostanić, J., E-mail: jasmina@nanosys.ihtm.bg.ac.rs [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Lončarević, D. [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Zlatar, M. [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Chemistry, Njegoševa 12, 11000 Belgrade (Serbia); Vlahović, F. [University of Belgrade, Innovation center of the Faculty of Chemistry, 11000 Belgrade (Serbia); Jovanović, D.M. [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia)

2016-10-05

Highlights: • Electronic effects of para substituted arylazo pyridone dyes. • Linear relationship between Hammett σ{sub p} constants and dyes photoreactivity. • The photocatalytic reactions facilitated by el.-acceptors and retarded by el.-donors. • Fukui functions to analyze the reactivity on concurrent sites within a molecule. • Hydroxyl radicals sustain attack from two reaction sites, depending on a substituent type. - Abstract: A series of arylazo pyridone dyes was synthesized by changing the type of the substituent group in the diazo moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The structural and electronic properties of the investigated dyes was calculated at the M062X/6-31 + G(d,p) level of theory. The observed good linear correlations between atomic charges and Hammett σ{sub p} constants provided a basis to discuss the transmission of electronic substituent effects through a dye framework. The reactivity of synthesized dyes was tested through their decolorization efficiency in TiO{sub 2} photocatalytic system (Degussa P-25). Quantitative structure-activity relationship analysis revealed a strong correlation between reactivity of investigated dyes and Hammett substituent constants. The reaction was facilitated by electron-withdrawing groups, and retarded by electron-donating ones. Quantum mechanical calculations was used in order to describe the mechanism of the photocatalytic oxidation reactions of investigated dyes and interpret their reactivities within the framework of the Density Functional Theory (DFT). According to DFT based reactivity descriptors, i.e. Fukui functions and local softness, the active site moves from azo nitrogen atom linked to benzene ring to pyridone carbon atom linked to azo bond, going from dyes with electron-donating groups to dyes with electron-withdrawing groups.

Quantitative structure-activity relationship analysis of substituted arylazo pyridone dyes in photocatalytic system: Experimental and theoretical study

International Nuclear Information System (INIS)

Dostanić, J.; Lončarević, D.; Zlatar, M.; Vlahović, F.; Jovanović, D.M.

2016-01-01

Highlights: • Electronic effects of para substituted arylazo pyridone dyes. • Linear relationship between Hammett σ_p constants and dyes photoreactivity. • The photocatalytic reactions facilitated by el.-acceptors and retarded by el.-donors. • Fukui functions to analyze the reactivity on concurrent sites within a molecule. • Hydroxyl radicals sustain attack from two reaction sites, depending on a substituent type. - Abstract: A series of arylazo pyridone dyes was synthesized by changing the type of the substituent group in the diazo moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The structural and electronic properties of the investigated dyes was calculated at the M062X/6-31 + G(d,p) level of theory. The observed good linear correlations between atomic charges and Hammett σ_p constants provided a basis to discuss the transmission of electronic substituent effects through a dye framework. The reactivity of synthesized dyes was tested through their decolorization efficiency in TiO_2 photocatalytic system (Degussa P-25). Quantitative structure-activity relationship analysis revealed a strong correlation between reactivity of investigated dyes and Hammett substituent constants. The reaction was facilitated by electron-withdrawing groups, and retarded by electron-donating ones. Quantum mechanical calculations was used in order to describe the mechanism of the photocatalytic oxidation reactions of investigated dyes and interpret their reactivities within the framework of the Density Functional Theory (DFT). According to DFT based reactivity descriptors, i.e. Fukui functions and local softness, the active site moves from azo nitrogen atom linked to benzene ring to pyridone carbon atom linked to azo bond, going from dyes with electron-donating groups to dyes with electron-withdrawing groups.

Mechanical properties of PET composites using multi-walled carbon nanotubes functionalized by inorganic and itaconic acids

Directory of Open Access Journals (Sweden)

A. May-Pat

2012-02-01

Full Text Available Multi-walled carbon nanotubes (MWCNTs were oxidized by two different acid treatments and further functionalized with itaconic acid (IA. The functionalized MWCNTs were used to fabricate Poly(ethylene terephthalate (PET composites by melt mixing. The presence of functional groups on the surface of the treated MWCNTs was confirmed by infrared spectroscopy and thermogravimetric analysis. The MWCNTs oxidized with a concentrated mixture of HNO3 and H2SO4 exhibited more oxygen containing functional groups (OH, COOH but also suffer larger structural degradation than those oxidized by a mild treatment based on diluted HNO3 followed by H2O2. PET composites were fabricated using the oxidized-only and oxidized followed by functionalization with IA MWCNTs. PET composites fabricated with MWCNT oxidized by mild conditions showed improved tensile strength and failure strain, while harsh MWCNT oxidation render them overly brittle.

Improvement in cardiac function and free fatty acid metabolism in a case of dilated cardiomyopathy with CD36 deficiency.

Science.gov (United States)

Hirooka, K; Yasumura, Y; Ishida, Y; Komamura, K; Hanatani, A; Nakatani, S; Yamagishi, M; Miyatake, K

2000-09-01

A 27-year-old man diagnosed as having dilated cardiomyopathy (DCM) without myocardial accumulation of 123I-beta-methyl-iodophenylpentadecanoic acid, and he was found to have type I CD36 deficiency. This abnormality of cardiac free fatty acid metabolism was also confirmed by other methods: 18F-fluoro-2-deoxyglucose positron emission tomography, measurements of myocardial respiratory quotient and cardiac fatty acid uptake. Although the type I CD36 deficiency was reconfirmed after 3 months, the abnormal free fatty acid metabolism improved after carvedilol therapy and was accompanied by improved cardiac function. Apart from a cause-and-effect relationship, carvedilol can improve cardiac function and increase free fatty acid metabolism in patients with both DCM and CD36 deficiency.

Single amino acid substitution in important hemoglobinopathies does not disturb molecular function and biological process

Directory of Open Access Journals (Sweden)

Viroj Wiwanitkit

2008-06-01

Full Text Available Viroj WiwanitkitDepartment of Laboratory Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, ThailandAbstract: Hemoglobin is an important protein found in the red cells of many animals. In humans, the hemoglobin is mainly distributed in the red blood cell. Single amino acid substitution is the main pathogenesis of most hemoglobin disorders. Here, the author used a new gene ontology technology to predict the molecular function and biological process of four important hemoglobin disorders with single substitution. The four studied important abnormal hemoglobins (Hb with single substitution included Hb S, Hb E, Hb C, and Hb J-Baltimore. Using the GoFigure server, the molecular function and biological process in normal and abnormal hemoglobins was predicted. Compared with normal hemoglobin, all studied abnormal hemoglobins had the same function and biological process. This indicated that the overall function of oxygen transportation is not disturbed in the studied hemoglobin disorders. Clinical findings of oxygen depletion in abnormal hemoglobin should therefore be due to the other processes rather than genomics, proteomics, and expression levels.Keywords: hemoglobin, amino acid, substitution, function

Effects of ioxaglic acid on cardiac functions during coronary arteriography in canines

Energy Technology Data Exchange (ETDEWEB)

Traegaardh, B. (Malmoe Allmaenna Sjukhus, Malmoe, Sweden); Lynch, P.R. (Temple Univ., Philadelphia, PA (USA). School of Medicine)

1983-01-01

The new monoacid dimer ioxaglic acid (P286), the non-ionic metrizamide (Amipaque) and diatrizoate (Renografin 76) were compared regarding their effects on left ventricular pressure, the first derivative of left ventricular pressure, aortic pressures and on ECG changes during left and right coronary angiography in dogs. Ioxaglate was found to affect most of these parameters less than diatrizoate probably due to its lower osmolality. Ioxaglate should be regarded suitable for coronary angiography. However, ioxaglate was found to have greater effects on the cardiac function than the equiosmolar metrizamide. This is probably due to the chemotoxicity of the anion or possibly to the sodium content of the ioxaglic acid solution.

Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Dron, Julien [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)], E-mail: julien.dron@up.univ-mrs.fr; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)

2007-12-12

The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF{sub 3}/methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L{sup -1}. Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices.

Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry

International Nuclear Information System (INIS)

Dron, Julien; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri

2007-01-01

The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF 3 /methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L -1 . Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices

Benefits of Docosahexaenoic Acid, Folic Acid, Vitamin D and Iodine on Foetal and Infant Brain Development and Function Following Maternal Supplementation during Pregnancy and Lactation

Directory of Open Access Journals (Sweden)

Nancy L. Morse

2012-07-01

Full Text Available Scientific literature is increasingly reporting on dietary deficiencies in many populations of some nutrients critical for foetal and infant brain development and function. Purpose: To highlight the potential benefits of maternal supplementation with docosahexaenoic acid (DHA and other important complimentary nutrients, including vitamin D, folic acid and iodine during pregnancy and/or breast feeding for foetal and/or infant brain development and/or function. Methods: English language systematic reviews, meta-analyses, randomised controlled trials, cohort studies, cross-sectional and case-control studies were obtained through searches on MEDLINE and the Cochrane Register of Controlled Trials from January 2000 through to February 2012 and reference lists of retrieved articles. Reports were selected if they included benefits and harms of maternal supplementation of DHA, vitamin D, folic acid or iodine supplementation during pregnancy and/or lactation. Results: Maternal DHA intake during pregnancy and/or lactation can prolong high risk pregnancies, increase birth weight, head circumference and birth length, and can enhance visual acuity, hand and eye co-ordination, attention, problem solving and information processing. Vitamin D helps maintain pregnancy and promotes normal skeletal and brain development. Folic acid is necessary for normal foetal spine, brain and skull development. Iodine is essential for thyroid hormone production necessary for normal brain and nervous system development during gestation that impacts childhood function. Conclusion: Maternal supplementation within recommended safe intakes in populations with dietary deficiencies may prevent many brain and central nervous system malfunctions and even enhance brain development and function in their offspring.

The Curtin–Hammett Principle

Indian Academy of Sciences (India)

IAS Admin

Here, we intend to provide a qualitative ... She works as. CSIR Senior Research Fellow. (Ext). ... conformational analysis, Pollak and Curtin put forward the fun- ..... A common question to the students in their practical classes is: how can the ...

Optical Sensing of Aromatic Amino Acids and Dipeptides by a Crown-Ether-Functionalized Perylene Bisimide Fluorophore.

Science.gov (United States)

Weißenstein, Annike; Saha-Möller, Chantu R; Würthner, Frank

2018-06-04

The host-guest binding properties of a fluorescent perylene bisimide (PBI) receptor equipped with crown ether were studied in detail with a series of aromatic amino acids and dipeptides by UV/Vis, fluorescence and NMR spectroscopy. Fluorescence titration experiments showed that electron-rich aromatic amino acids and dipeptides strongly quench the fluorescence of the electron-poor PBI host molecule. Benesi-Hildebrand plots of fluorescence titration data confirmed the formation of host-guest complexes with 1:2 stoichiometry. Binding constants determined by global analysis of UV/Vis and fluorescence titration experiments revealed values between 10 3  m -1 and 10 5  m -1 in acetonitrile/methanol (9:1) at 23 °C. These data showed that amino acid l-Trp having an indole group and dipeptides containing this amino acid bind to the PBI receptor more strongly than other amino acids and dipeptides investigated here. For dipeptides containing l-Trp or l-Tyr, the binding strength is dependent on the distance between the ammonium group and the aromatic unit of the amino acids and dipeptides leading to a strong sensitivity for Ala-Trp dipeptide. 1D and 2D NMR experiments also corroborated 1:2 host-guest complexation and indicated formation of two diastereomeric species of host-guest complexes. The studies have shown that a properly functionalized PBI fluorophore functions as a molecular probe for the optical sensing of aromatic amino acids and dipeptides. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ligand-functionalized degradable polyplexes formed by cationic poly(aspartic acid)-grafted chitosan-cyclodextrin conjugates

Science.gov (United States)

Song, Hai-Qing; Li, Rui-Quan; Duan, Shun; Yu, Bingran; Zhao, Hong; Chen, Da-Fu; Xu, Fu-Jian

2015-03-01

Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE-FA/pDNA, and ternary CCPE-FA/CCPE/pDNA (prepared by layer-by-layer assembly) polyplexes were investigated in detail using different cell lines. The CCPE-based polyplexes displayed much higher transfection efficiencies than the CS-based polyplexes reported earlier by us. The ternary polyplexes of CCPE-FA/CCPE/pDNA produced excellent gene transfection abilities in the folate receptor (FR)-positive tumor cells. This work would provide a promising means to produce highly efficient polyplexes for future gene therapy applications.Polypeptide-based degradable polyplexes attracted considerable attention in drug delivery systems. Polysaccharides including cyclodextrin (CD), dextran, and chitosan (CS) were readily grafted with cationic poly(aspartic acid)s (PAsps). To further enhance the transfection performances of PAsp-based polyplexes, herein, different types of ligand (folic acid, FA)-functionalized degradable polyplexes were proposed based on the PAsp-grafted chitosan-cyclodextrin conjugate (CCPE), where multiple β-CDs were tied on a CS chain. The FA-functionalized CCPE (i.e., CCPE-FA) was obtained via a host-guest interaction between the CD units of CCPE and the adamantane (Ad) species of Ad-modified FA (Ad-FA). The resulting CCPE/pDNA, CCPE

Lipidization of Simple and di-Functional Amino Acids

International Nuclear Information System (INIS)

Zainab Idris; Mohd Wahid Samsudin; Salmiah Ahmad

2013-01-01

This paper discuss the modification of azelaic acid into its applicable form by attachment of both its carboxyl sites to N-terminal of amino acid ethyl ester forming amide linkages in anhydrous medium. Acylation of glycine ethyl ester hydrochloride with azelaic acid dichloride was best conducted in a 100 % anhydrous medium. L-amino acid ethyl ester bearing a primary hydroxyl group on its side chain gave mixtures of product and variation in composition depending on the mole ratio of reactants used. Reduction in purity was also observed for L-amino acid ethyl ester with primary -SH group on its side chain as compared to L-amino acid ethyl ester having -SCH 3 group on the L-amino acid side chain. The diamidoester of azelaic acid with L-alanine ethyl ester, L-valine ethyl ester, L-leucine ethyl ester and L-glutamic acid diethyl ester were in good yield when prepared through the modified Schotten-Baumann reaction conditions. (author)

Supervanadophile: Complexation, preconcentration and transport studies of vanadium by octa functionalized calix [4] resorcinarene - hydroxamic acid

International Nuclear Information System (INIS)

Jain, V. K.; Pillai, S. G.; Gupte, H. S.

2008-01-01

A new octa functionalized calix[4] resorcinarene bearing eight hydroxamic acid groups has been synthesized and its analytical properties have been investigated. To elucidate the structure of the compound, elemental analysis, fourier transform infrared and 1 H NMR spectral data have been used. The compound showed high affinity and selectivity for vanadium(V) in presence of large quantities of associated metal ions. The complexation of vanadium(V) with octa functionalized calix[4] resorcinarene bearing eight hydroxamic acid has a 4:1 metal: ligand stoichiometry as evaluated by Job's plot. A spectrophotometric method is proposed for the extractive determination of vanadium(V) in an acidic medium in the presence of diversified matrix, and verified by inductively coupled plasma-atomic emission spectrometry. Under the optimum condition of acidity, solvent, interfering ions and octa functionalized calix[4] resorcinarene bearing eight hydroxamic acid concentration, the molar absorptivity of the complex is 5630 1 mol -1 cm -1 at 495 nm. The system obeys Beer's law over the range 0.125-8.75 μg ml -1 of vanadium(V) with Sandell sensitivity 0.009 μg cm -2 . The preconcentration factor and overall stability constant evaluated at 25 d eg C were 142 and 14.18, respectively. The complexation is characterized by favorable enthalpy and entropy changes. Liquid membrane transport studies of vanadium(V) were carried out from source to the receiving phase under controlled conditions and a mechanism for transport is suggested. To check the validity of the proposed method, vanadium is determined in environmental, biological samples and some standard reference materials from NIST and BCS

Impact of ursodeoxycholic acid on a CCK1R cholesterol-binding site may contribute to its positive effects in digestive function.

Science.gov (United States)

Desai, Aditya J; Dong, Maoqing; Harikumar, Kaleeckal G; Miller, Laurence J

2015-09-01

Dysfunction of the type 1 cholecystokinin (CCK) receptor (CCK1R) as a result of increased gallbladder muscularis membrane cholesterol has been implicated in the pathogenesis of cholesterol gallstones. Administration of ursodeoxycholic acid, which is structurally related to cholesterol, has been shown to have beneficial effects on gallstone formation. Our aims were to explore the possible direct effects and mechanism of action of bile acids on CCK receptor function. We studied the effects of structurally related hydrophobic chenodeoxycholic acid and hydrophilic ursodeoxycholic acid in vitro on CCK receptor function in the setting of normal and elevated membrane cholesterol. We also examined their effects on a cholesterol-insensitive CCK1R mutant (Y140A) disrupting a key site of cholesterol action. The results show that, similar to the impact of cholesterol on CCK receptors, bile acid effects were limited to CCK1R, with no effects on CCK2R. Chenodeoxycholic acid had a negative impact on CCK1R function, while ursodeoxycholic acid had no effect on CCK1R function in normal membranes but was protective against the negative impact of elevated cholesterol on this receptor. The cholesterol-insensitive CCK1R mutant Y140A was resistant to effects of both bile acids. These data suggest that bile acids compete with the action of cholesterol on CCK1R, probably by interacting at the same site, although the conformational impact of each bile acid appears to be different, with ursodeoxycholic acid capable of correcting the abnormal conformation of CCK1R in a high-cholesterol environment. This mechanism may contribute to the beneficial effect of ursodeoxycholic acid in reducing cholesterol gallstone formation. Copyright © 2015 the American Physiological Society.

Simultaneous Reduction and Functionalization of Graphene Oxide by 4-Hydrazinobenzenesulfonic Acid for Polymer Nanocomposites

Directory of Open Access Journals (Sweden)

Song-Jie Qiao

2016-02-01

Full Text Available Graphene oxide (GO was functionalized and reduced simultaneously by a new reductant, 4-hydrazinobenzenesulfonic acid (HBS, with a one-step and environmentally friendly process. The hydrophilic sulfonic acid group in HBS was grafted onto the surface of GO through a covalent bond. The successful preparation of HBS reduced GO (HBS-rGO was testified by scanning electron microscope (SEM, X-ray diffraction (XRD, Raman spectroscopy, Fourier transform infrared spectra (FTIR, X-ray photoelectron spectroscopic (XPS and thermogravimetric analysis (TGA. The interlayer space of HBS-rGO was increased to 1.478 nm from 0.751 nm for GO, resulting in a subdued Van der Waals’ force between layers and less possibility to form aggregations. The aqueous dispersibility of graphene was improved to 13.49 mg/mL from 0.58 mg/mL after the functionalization. The viscosity of the epoxy resin based HBS-rGO composite could be regulated by an adjustment of the content of HBS-rGO. This study provides a new and applicable approach for the preparation of hydrophilic functionalized graphene, and makes it possible for the application of graphene in some functional polymer nanocomposites, such as specialty water-based coatings.

Identification of functional residues essential for dehalogenation by the non-stereospecific α-haloalkanoic acid dehalogenase from Rhizobium sp. RC1.

Science.gov (United States)

Hamid, Azzmer Azzar Abdul; Hamid, Tengku Haziyamin Tengku Abdul; Wahab, Roswanira Abdul; Huyop, Fahrul

2015-03-01

The non-stereospecific α-haloalkanoic acid dehalogenase DehE from Rhizobium sp. RC1 catalyzes the removal of the halide from α-haloalkanoic acid D,L-stereoisomers and, by doing so, converts them into hydroxyalkanoic acid L,D-stereoisomers, respectively. DehE has been extensively studied to determine its potential to act as a bioremediation agent, but its structure/function relationship has not been characterized. For this study, we explored the functional relevance of several putative active-site amino acids by site-specific mutagenesis. Ten active-site residues were mutated individually, and the dehalogenase activity of each of the 10 resulting mutants in soluble cell lysates against D- and L-2-chloropropionic acid was assessed. Interestingly, the mutants W34→A,F37→A, and S188→A had diminished activity, suggesting that these residues are functionally relevant. Notably, the D189→N mutant had no activity, which strongly implies that it is a catalytically important residue. Given our data, we propose a dehalogenation mechanism for DehE, which is the same as that suggested for other non-stereospecific α-haloalkanoic acid dehalogenases. To the best of our knowledge, this is the first report detailing a functional aspect for DehE, and our results could help pave the way for the bioengineering of haloalkanoic acid dehalogenases with improved catalytic properties. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dietary acid load and renal function have varying effects on blood acid-base status and exercise performance across age and sex.

Science.gov (United States)

Hietavala, Enni-Maria; Stout, Jeffrey R; Frassetto, Lynda A; Puurtinen, Risto; Pitkänen, Hannu; Selänne, Harri; Suominen, Harri; Mero, Antti A

2017-12-01

Diet composition influences acid-base status of the body. This may become more relevant as renal functional capacity declines with aging. We examined the effects of low (LD) versus high dietary acid load (HD) on blood acid-base status and exercise performance. Participants included 22 adolescents, 33 young adults (YA), and 33 elderly (EL), who followed a 7-day LD and HD in a randomized order. At the end of both diet periods the subjects performed a cycle ergometer test (3 × 10 min at 35%, 55%, 75%, and (except EL) until exhaustion at 100% of maximal oxygen uptake). At the beginning of and after the diet periods, blood samples were collected at rest and after all workloads. Oxygen uptake, respiratory exchange ratio (RER), and heart rate (HR) were monitored during cycling. In YA and EL, bicarbonate (HCO 3 - ) and base excess (BE) decreased over the HD period, and HCO 3 - , BE, and pH were lower at rest after HD compared with LD. In YA and EL women, HCO 3 - and BE were lower at submaximal workloads after HD compared with LD. In YA women, the maximal workload was 19% shorter and maximal oxygen uptake, RER, and HR were lower after HD compared with LD. Our data uniquely suggests that better renal function is associated with higher availability of bases, which may diminish exercise-induced acidosis and improve maximal aerobic performance. Differences in glomerular filtration rate between the subject groups likely explains the larger effects of dietary acid load in the elderly compared with younger subjects and in women compared with men.

Acute exposure to realistic acid fog: effects on respiratory function and airway responsiveness in asthmatics.

Science.gov (United States)

Leduc, D; Fally, S; De Vuyst, P; Wollast, R; Yernault, J C

1995-11-01

Naturally occurring fogs in industrialized cities are contaminated by acidic air pollutants. In Brussels, Belgium, the pH of polluted fogwater may be as low as 3 with osmolarity as low as 30 mOsm. In order to explore short-term respiratory effects of a realistic acid-polluted fog, we collected samples of acid fog in Brussels, Belgium, which is a densely populated and industrialized city, we defined characteristics of this fog and exposed asthmatic volunteers at rest through a face mask to fogs with physical and chemical characteristics similar to those of natural fogs assessed in this urban area. Fogwater was sampled using a screen collector where droplets are collected by inertial impaction and chemical content of fogwater was assessed by measurement of conductivity, pH, visible colorimetry, high pressure liquid chromatography, and atomic absorption spectrophotometry over a period of one year. The fogwater composition was dominated by NH4+ and SO4- ions. First we evaluated the possible effect of fog acidity alone. For this purpose 14 subjects with asthma were exposed at rest for 1 hr [mass median aerodynamic diameter to a large-particle (MMAD), 9 microns] aerosol with H2SO4 concentration of 500 micrograms/m3 (pH 2.5) and osmolarity of 300 mOsm. We did not observe significant change in pulmonary function or bronchial responsiveness to metacholine. In the second part of the work, 10 asthmatic subjects were exposed to acid fog (MMAD, 7 microns) containing sulfate and ammonium ions (major ions recovered in naturally occurring fogs) with pH 3.5 and osmolarity 30 mOsm. Again, pulmonary function and bronchial reactivity were not modified after inhalation of this fog. It was concluded that short-term exposure to acid fog reproducing acidity and hypoosmolarity of natural polluted fogs does not induce bronchoconstriction and does not change bronchial responsiveness in asthmatics.

Sorption of humic acid to functionalized multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Wang, Fei; Yao, Jun; Chen, Huilun; Yi, Zhengji; Xing, Baoshan

2013-01-01

The environmental behavior of carbon nanotubes (CNTs) and humic acid (HA) is a prominent concern, but effect of functionalities on their sorption is not clear yet. Functionalized multi-walled CNTs (MCNT15) and HA were used to study their sorption behavior. Sorption rate of HA to MCNTs was dominantly controlled by its diffusion from liquid-MCNT boundary to MCNT surfaces. The sorption is in the sequence of MCNT15 > MCNT15-NH 2 > MCNT15-OH > MCNT15-COOH > MCNT15-Ni, which was dependent on their surface area and meso- and macro-pore volume. The functionalities of MCNTs regulated the sorption by affecting their interaction mechanisms (i.e., H-bonding, π–π, and hydrophobic interaction). Additionally, the amount of these functionalities on the MCNT surface reduced indirectly the sorption sites due to the steric hindrance. Electrostatic repulsion deceased the sorption of HA by MCNTs with increasing pH. This study demonstrated the importance of functionalities on the MCNTs for the sorption of HA. -- Highlights: •HA sorption kinetics was well fitted using Lagergren pseudo second-order model. •Sorption rate of HA was controlled by diffusion from liquid-MCNT boundary to MCNT surfaces. •Sorption was dependent on their surface area and meso- and macro-pore volume. •Functionalities of MCNTs regulated the sorption by affecting interaction mechanisms. -- The functionalities of MCNTs regulated the sorption behavior between MCNTs and HA

Synthesis and physical-chemical properties of functional derivatives of 3-benzyl-8-propylxanthinyl-7-acetic acid

Directory of Open Access Journals (Sweden)

E. K. Mikhal’chenko

2017-08-01

Full Text Available Introduction. Synthetic research of new biologically active compounds occupies an important place in modern pharmaceutical science.Thus it is important to develop techniques for the biologically active substances functionalization. Esters and amides take special place among the variety of functional derivatives of organic acids,. These fragments are well-known pharmacophores and could be found in a wide range of drugs. Thus, the nootropic agent pyracetam is 2-oxo-1-pyrolidineacetamide, and is the selective antagonist of β-adrenoreceptores; atenolol is a derivative of benzeneacetamide. Substituted acetamide and ester fragments are also present in the structures of aprofen, spasmolitin, acetylidine and β-lactam cephalosporins and penicillins antibiotics.Aim of our research was the synthetic method development for functional derivatives of 3-benzyl-8-propylxanthinyl-7-acetic acid and the study of their physical-chemical properties. Materials and methods. Melting points were determined using capillary method on DMP (M. 1Н NMR-spectra were recorded by Varian Mercury VX-200 device (company «Varian» – USA solvent – (DMSO-d6, internal standard – ТМS. Elemental analysis of obtained compounds was produced on device Elementar Vario L cube. Chemical shifts were reported in ppm (parts per million values. Infrared (IR spectra were measured on a Bruker Alpha instrument using a potassium bromide (KBr disk, scanning from 400 to 4000 cm-1. Results and discussion. We selected 3-benzyl-8-propylxanthinyl-7-acetic acid as initial compound for our study. For synthesis of hexyl, heptyl, octyl, nonyl, decyl and benzyl esters of 3-benzyl-8-propylxanthinyl-7-acetic acid we used alternative method, that included alkylation of sodium salts of acids with alkyl halogens. Reaction was made at DMF medium by reflux of reagents. Next stage of our research was the synthesis of amides of 3-beznyl-8-propylxanthinyl-7-acetic acid by the reaction of ethyl or propyl esters

Improved stability and antidiabetic potential of insulin containing folic acid functionalized polymer stabilized multilayered liposomes following oral administration

DEFF Research Database (Denmark)

Agrawal, Ashish Kumar; Harde, Harshad; Thanki, Kaushik

2014-01-01

The present study reports the folic acid (FA) functionalized insulin loaded stable liposomes with improved bioavailability following oral administration. Liposomes were stabilized by alternating coating of negatively charged poly(acrylic acid) (PAA) and positively charged poly(allyl amine...

Combined effects of simulated acid rain and lanthanum chloride on chloroplast structure and functional elements in rice.

Science.gov (United States)

Hu, Huiqing; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

2016-05-01

Acid rain and rare earth element (REE) pollution exist simultaneously in many agricultural regions. However, how REE pollution and acid rain affect plant growth in combination remains largely unknown. In this study, the combined effects of simulated acid rain and lanthanum chloride (LaCl3) on chloroplast morphology, chloroplast ultrastructure, functional element contents, chlorophyll content, and the net photosynthetic rate (P n) in rice (Oryza sativa) were investigated by simulating acid rain and rare earth pollution. Under the combined treatment of simulated acid rain at pH 4.5 and 0.08 mM LaCl3, the chloroplast membrane was smooth, proteins on this membrane were uniform, chloroplast structure was integrated, and the thylakoids were orderly arranged, and simulated acid rain and LaCl3 exhibited a mild antagonistic effect; the Mg, Ca, Mn contents, the chlorophyll content, and the P n increased under this combined treatment, with a synergistic effect of simulated acid rain and LaCl3. Under other combined treatments of simulated acid rain and LaCl3, the chloroplast membrane surface was uneven, a clear "hole" was observed on the surface of chloroplasts, and the thylakoids were dissolved and loose; and the P n and contents of functional elements (P, Mg, K, Ca, Mn, Fe, Ni, Cu, Zn and Mo) and chlorophyll decreased. Under these combined treatments, simulated acid rain and LaCl3 exhibited a synergistic effect. Based on the above results, a model of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis was established in order to reveal the combined effects on plant photosynthesis, especially on the photosynthetic organelle-chloroplast. Our results would provide some references for further understanding the mechanism of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis.

Functionalized-graphene modified graphite electrode for the selective determination of dopamine in presence of uric acid and ascorbic acid.

Science.gov (United States)

Mallesha, Malledevaru; Manjunatha, Revanasiddappa; Nethravathi, C; Suresh, Gurukar Shivappa; Rajamathi, Michael; Melo, Jose Savio; Venkatesha, Thimmappa Venkatarangaiah

2011-06-01

Graphene is chemically synthesized by solvothermal reduction of colloidal dispersions of graphite oxide. Graphite electrode is modified with functionalized-graphene for electrochemical applications. Electrochemical characterization of functionalized-graphene modified graphite electrode (FGGE) is carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The behavior of FGGE towards ascorbic acid (AA), dopamine (DA) and uric acid (UA) has been investigated by CV, differential pulse voltammetry (DPV) and chronoamperommetry (CA). The FGGE showed excellent catalytic activity towards electrochemical oxidation of AA, DA and UA compared to that of the bare graphite electrode. The electrochemical oxidation signals of AA, DA and UA are well separated into three distinct peaks with peak potential separation of 193mv, 172mv and 264mV between AA-DA, DA-UA and AA-UA respectively in CV studies and the corresponding peak potential separations in DPV mode are 204mv, 141mv and 345mv. The FGGE is successfully used for the simultaneous detection of AA, DA and UA in their ternary mixture and DA in serum and pharmaceutical samples. The excellent electrocatalytic behavior of FGGE may lead to new applications in electrochemical analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

Functionalization of chitosan/poly(lactic acid-glycolic acid) sintered microsphere scaffolds via surface heparinization for bone tissue engineering.

Science.gov (United States)

Jiang, Tao; Khan, Yusuf; Nair, Lakshmi S; Abdel-Fattah, Wafa I; Laurencin, Cato T

2010-06-01

Scaffolds exhibiting biological recognition and specificity play an important role in tissue engineering and regenerative medicine. The bioactivity of scaffolds in turn influences, directs, or manipulates cellular responses. In this study, chitosan/poly(lactic acid-co-glycolic acid) (chitosan/PLAGA) sintered microsphere scaffolds were functionalized via heparin immobilization. Heparin was successfully immobilized on chitosan/PLAGA scaffolds with controllable loading efficiency. Mechanical testing showed that heparinization of chitosan/PLAGA scaffolds did not significantly alter the mechanical properties and porous structures. In addition, the heparinized chitosan/PLAGA scaffolds possessed a compressive modulus of 403.98 +/- 19.53 MPa and a compressive strength of 9.83 +/- 0.94 MPa, which are in the range of human trabecular bone. Furthermore, the heparinized chitosan/PLAGA scaffolds had an interconnected porous structure with a total pore volume of 30.93 +/- 0.90% and a median pore size of 172.33 +/- 5.89 mum. The effect of immobilized heparin on osteoblast-like MC3T3-E1 cell growth was investigated. MC3T3-E1 cells proliferated three dimensionally throughout the porous structure of the scaffolds. Heparinized chitosan/PLAGA scaffolds with low heparin loading (1.7 microg/scaffold) were shown to be capable of stimulating MC3T3-E1 cell proliferation by MTS assay and cell differentiation as evidenced by elevated osteocalcin expression when compared with nonheparinized chitosan/PLAGA scaffold and chitosan/PLAGA scaffold with high heparin loading (14.1 microg/scaffold). This study demonstrated the potential of functionalizing chitosan/PLAGA scaffolds via heparinization with improved cell functions for bone tissue engineering applications.

Roles of acidic functional groups of carbon fiber surfaces in enhancing interfacial adhesion behavior

International Nuclear Information System (INIS)

Park, Soo-Jin; Kim, Byung-Joo

2005-01-01

The gas phase ozone treatment was used as a method to bind acidic oxygen functional groups on carbon fiber surfaces. The ozone treatment on carbon fibers was varied with the ozone concentration and treatment time. Surface analyses of the carbon fibers before and after treatments were performed by FT-IR, X-ray photoelectron spectrometer (XPS), and dynamic contact angle measurements. Mechanical interfacial properties of the fibers/polymer composites were investigated by using critical stress intensity factor (K IC ) and critical energy release rate (G IC ) measurements. From the results of FT-IR and XPS, it was observed that the oxygen functional groups, such as -OH, O-C=O, C=O, and C-O, were attached on the carbon fiber surfaces after the ozone treatment. The mechanical interfacial properties of the composites also showed higher values than those of untreated composites. Ozone treatment is attributed to the increase of both the acidic functional groups and the degree of adhesion at interfaces between the fibers and polymeric resin in composites

Amino acid composition reveals functional diversity of zooplankton in tropical lakes related to geography, taxonomy and productivity.

Science.gov (United States)

Aranguren-Riaño, Nelson J; Guisande, Cástor; Shurin, Jonathan B; Jones, Natalie T; Barreiro, Aldo; Duque, Santiago R

2018-04-16

Variation in resource use among species determines their potential for competition and co-existence, as well as their impact on ecosystem processes. Planktonic crustaceans consume a range of micro-organisms that vary among habitats and species, but these differences in resource consumption are difficult to characterize due to the small size of the organisms. Consumers acquire amino acids from their diet, and the composition of tissues reflects both the use of different resources and their assimilation in proteins. We examined the amino acid composition of common crustacean zooplankton from 14 tropical lakes in Colombia in three regions (the Amazon floodplain, the eastern range of the Andes, and the Caribbean coast). Amino acid composition varied significantly among taxonomic groups and the three regions. Functional richness in amino acid space was greatest in the Amazon, the most productive region, and tended to be positively related to lake trophic status, suggesting the niche breadth of the community could increase with ecosystem productivity. Functional evenness increased with lake trophic status, indicating that species were more regularly distributed within community-wide niche space in more productive lakes. These results show that zooplankton resource use in tropical lakes varies with both habitat and taxonomy, and that lake productivity may affect community functional diversity and the distribution of species within niche space.

4-Phenylbutyric Acid Reveals Good Beneficial Effects on Vital Organ Function via Anti-Endoplasmic Reticulum Stress in Septic Rats.

Science.gov (United States)

Liu, Liangming; Wu, Huiling; Zang, JiaTao; Yang, Guangming; Zhu, Yu; Wu, Yue; Chen, Xiangyun; Lan, Dan; Li, Tao

2016-08-01

Sepsis and septic shock are the common complications in ICUs. Vital organ function disorder contributes a critical role in high mortality after severe sepsis or septic shock, in which endoplasmic reticulum stress plays an important role. Whether anti-endoplasmic reticulum stress with 4-phenylbutyric acid is beneficial to sepsis and the underlying mechanisms are not known. Laboratory investigation. State Key Laboratory of Trauma, Burns and Combined Injury. Sprague-Dawley rats. Using cecal ligation and puncture-induced septic shock rats, lipopolysaccharide-treated vascular smooth muscle cells, and cardiomyocytes, effects of 4-phenylbutyric acid on vital organ function and the relationship with endoplasmic reticulum stress and endoplasmic reticulum stress-mediated inflammation, apoptosis, and oxidative stress were observed. Conventional treatment, including fluid resuscitation, vasopressin, and antibiotic, only slightly improved the hemodynamic variable, such as mean arterial blood pressure and cardiac output, and slightly improved the vital organ function and the animal survival of septic shock rats. Supplementation of 4-phenylbutyric acid (5 mg/kg; anti-endoplasmic reticulum stress), especially administered at early stage, significantly improved the hemodynamic variables, vital organ function, such as liver, renal, and intestinal barrier function, and animal survival in septic shock rats. 4-Phenylbutyric acid application inhibited the endoplasmic reticulum stress and endoplasmic reticulum stress-related proteins, such as CCAAT/enhancer-binding protein homologous protein in vital organs, such as heart and superior mesenteric artery after severe sepsis. Further studies showed that 4-phenylbutyric acid inhibited endoplasmic reticulum stress-mediated cytokine release, apoptosis, and oxidative stress via inhibition of nuclear factor-κB, caspase-3 and caspase-9, and increasing glutathione peroxidase and superoxide dismutase expression, respectively. Anti

Ursodeoxycholic acid attenuates colonic epithelial secretory function

Science.gov (United States)

Kelly, Orlaith B; Mroz, Magdalena S; Ward, Joseph B J; Colliva, Carolina; Scharl, Michael; Pellicciari, Roberto; Gilmer, John F; Fallon, Padraic G; Hofmann, Alan F; Roda, Aldo; Murray, Frank E; Keely, Stephen J

2013-01-01

Dihydroxy bile acids, such as chenodeoxycholic acid (CDCA), are well known to promote colonic fluid and electrolyte secretion, thereby causing diarrhoea associated with bile acid malabsorption. However, CDCA is rapidly metabolised by colonic bacteria to ursodeoxycholic acid (UDCA), the effects of which on epithelial transport are poorly characterised. Here, we investigated the role of UDCA in the regulation of colonic epithelial secretion. Cl− secretion was measured across voltage-clamped monolayers of T84 cells and muscle-stripped sections of mouse or human colon. Cell surface biotinylation was used to assess abundance/surface expression of transport proteins. Acute (15 min) treatment of T84 cells with bilateral UDCA attenuated Cl− secretory responses to the Ca2+ and cAMP-dependent secretagogues carbachol (CCh) and forskolin (FSK) to 14.0 ± 3.8 and 40.2 ± 7.4% of controls, respectively (n= 18, P acid (LCA). Accordingly, LCA (50–200 μm) enhanced agonist-induced secretory responses in vitro and a metabolically stable UDCA analogue, 6α-methyl-UDCA, exerted anti-secretory actions in vitro and in vivo. In conclusion, UDCA exerts direct anti-secretory actions on colonic epithelial cells and metabolically stable derivatives of the bile acid may offer a new approach for treating intestinal diseases associated with diarrhoea. PMID:23507881

Dual responsive dysprosium-doped hydroxyapatite particles and toxicity reduction after functionalization with folic and glucuronic acids

Energy Technology Data Exchange (ETDEWEB)

Sánchez Lafarga, Ana Karen; Pacheco Moisés, Fermín P. [Departamento de Química, Universidad de Guadalajara, Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico); Gurinov, Andrey [Research Resources Center for Magnetic Resonance, Saint Petersburg State University, Universitetskij pr. 26, 198504 St. Petersburg (Russian Federation); Ortiz, Genaro Gabriel [Laboratorio Desarrollo-Envejecimiento, Enfermedades Neurodegenerativas, Centro de Investigación Biomédica de Occidente (CIBO), Instituto Mexicano de Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Carbajal Arízaga, Gregorio Guadalupe, E-mail: gregoriocarbajal@yahoo.com.mx [Departamento de Química, Universidad de Guadalajara, Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico)

2015-03-01

The development of probes for biomedical applications demands materials with low toxicity levels besides fluorescence or magnetic properties to be detected by confocal microscopes or MRI resonators. Several drug delivery systems or other biomedical materials prepared with hydroxyapatite have been proposed, however, toxicity effects might arise when the size of particles is nanometric. In this study, hydroxyapatite functionalized with glucuronic or folic acids presented lower oxidative stress, measured from lipoperoxides and nitric oxide indicators in rats than pure hydroxyapatite. In separated experiments, hydroxyapatite was doped with dysprosium cations by coprecipitation producing a single crystal phase with fluorescent properties easily visualized by confocal microscopy when excited at 488 nm. These particles also presented the ability to modify the proton relaxation time in T1 maps collected by magnetic resonance imaging. These modified hydroxyapatite nanoparticles could be candidates to design bimodal probes with low toxicity. - Highlights: • Hydroxyapatite functionalized with glucuronic acid reduced oxidative stress in rats. • Functionalization with folic acid reduced oxidative stress in rats. • Dysprosium doping does not affect the crystalline structure of hydroxyapatite. • Dysprosium doped particles are visible in fluorescent microscope. • Dysprosium doped particles act as MRI contrast agents.

Dual responsive dysprosium-doped hydroxyapatite particles and toxicity reduction after functionalization with folic and glucuronic acids

International Nuclear Information System (INIS)

Sánchez Lafarga, Ana Karen; Pacheco Moisés, Fermín P.; Gurinov, Andrey; Ortiz, Genaro Gabriel; Carbajal Arízaga, Gregorio Guadalupe

2015-01-01

The development of probes for biomedical applications demands materials with low toxicity levels besides fluorescence or magnetic properties to be detected by confocal microscopes or MRI resonators. Several drug delivery systems or other biomedical materials prepared with hydroxyapatite have been proposed, however, toxicity effects might arise when the size of particles is nanometric. In this study, hydroxyapatite functionalized with glucuronic or folic acids presented lower oxidative stress, measured from lipoperoxides and nitric oxide indicators in rats than pure hydroxyapatite. In separated experiments, hydroxyapatite was doped with dysprosium cations by coprecipitation producing a single crystal phase with fluorescent properties easily visualized by confocal microscopy when excited at 488 nm. These particles also presented the ability to modify the proton relaxation time in T1 maps collected by magnetic resonance imaging. These modified hydroxyapatite nanoparticles could be candidates to design bimodal probes with low toxicity. - Highlights: • Hydroxyapatite functionalized with glucuronic acid reduced oxidative stress in rats. • Functionalization with folic acid reduced oxidative stress in rats. • Dysprosium doping does not affect the crystalline structure of hydroxyapatite. • Dysprosium doped particles are visible in fluorescent microscope. • Dysprosium doped particles act as MRI contrast agents

Transglycosylation of gallic acid by using Leuconostoc glucansucrase and its characterization as a functional cosmetic agent.

Science.gov (United States)

Nam, Seung-Hee; Park, Jeongjin; Jun, Woojin; Kim, Doman; Ko, Jin-A; Abd El-Aty, A M; Choi, Jin Young; Kim, Do-Ik; Yang, Kwang-Yeol

2017-12-22

Gallic acid glycoside was enzymatically synthesized by using dextransucrase and sucrose from gallic acid. After purification by butanol partitioning and preparative HPLC, gallic acid glucoside was detected at m/z 355 (C 13 , H 16 , O 10 , Na) + by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The yield of gallic acid glucoside was found to be 35.7% (114 mM) by response surface methodology using a reaction mixture of 319 mM gallic acid, 355 mM sucrose, and 930 mU/mL dextransucrase. The gallic acid glucoside obtained showed 31% higher anti-lipid peroxidation and stronger inhibition (Ki = 1.23 mM) against tyrosinase than that shown by gallic acid (Ki = 1.98 mM). In UVB-irradiated human fibroblast cells, gallic acid glucoside lowered matrix metalloproteinase-1 levels and increased the collagen content, which was indicative of a stronger anti-aging effect than that of gallic acid or arbutin. These results indicated that gallic acid glucoside is likely a superior cosmetic ingredient with skin-whitening and anti-aging functions.

Synthesis, hybridization characteristics, and fluorescence properties of oligonucleotides modified with nucleobase-functionalized locked nucleic acid adenosine and cytidine monomers.

Science.gov (United States)

Kaura, Mamta; Kumar, Pawan; Hrdlicka, Patrick J

2014-07-03

Conformationally restricted nucleotides such as locked nucleic acid (LNA) are very popular as affinity-, specificity-, and stability-enhancing modifications in oligonucleotide chemistry to produce probes for nucleic acid targeting applications in molecular biology, biotechnology, and medicinal chemistry. Considerable efforts have been devoted in recent years to optimize the biophysical properties of LNA through additional modification of the sugar skeleton. We recently introduced C5-functionalization of LNA uridines as an alternative and synthetically more straightforward approach to improve the biophysical properties of LNA. In the present work, we set out to test the generality of this concept by studying the characteristics of oligonucleotides modified with four different C5-functionalized LNA cytidine and C8-functionalized LNA adenosine monomers. The results strongly suggest that C5-functionalization of LNA pyrimidines is indeed a viable approach for improving the binding affinity, target specificity, and/or enzymatic stability of LNA-modified ONs, whereas C8-functionalization of LNA adenosines is detrimental to binding affinity and specificity. These insights will impact the future design of conformationally restricted nucleotides for nucleic acid targeting applications.

Biliary tract enhancement in gadoxetic acid-enhanced MRI correlates with liver function biomarkers

International Nuclear Information System (INIS)

Noda, Yoshifumi; Goshima, Satoshi; Kajita, Kimihiro; Kawada, Hiroshi; Kawai, Nobuyuki; Koyasu, Hiromi; Matsuo, Masayuki; Bae, Kyongtae T.

2016-01-01

Purpose: To evaluate the association between gadoxetic-acid-enhanced magnetic resonance (MR) imaging measurements and laboratory and clinical biomarkers of liver function and fibrosis. Materials and methods: One hundred thirty nine consecutive patients with suspected liver disease or liver tumor underwent gadoxetic-acid-enhanced MR imaging. MR imaging measurements during the hepatobiliary phase included biliary tract structure-to-muscle signal intensity ratio (SIR). These measurements were compared with Child-Pugh classification, end-stage liver disease (MELD) score, and aspartate aminotransferase-to-platelet ratio index (APRI). Results: The SIRs of cystic duct and common bile duct were significantly correlated with Child-Pugh classification (P = 0.012 for cystic duct and P < 0.0001 for common bile duct), MELD score (P = 0.0016 and P = 0.0033), and APRI (P = 0.0022 and P = 0.0015). The sensitivity, specificity, and area under the receiver-operating-characteristic curve were: (74%, 88%, 0.86) with the SIR of common bile duct for the detection of patients with Child-Pugh class B or C; (100%, 87%, 0.94) with the SIR of cystic duct for MELD score (>10); (65%, 76%, 0.70) with the SIR of common bile duct for APRI (>1.5). Conclusion: Gadoxetic-acid contrast enhancement of cystic duct and common bile duct could be used as biomarkers to assess liver function.

Biliary tract enhancement in gadoxetic acid-enhanced MRI correlates with liver function biomarkers

Energy Technology Data Exchange (ETDEWEB)

Noda, Yoshifumi [Department of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu, 501-1194 (Japan); Goshima, Satoshi, E-mail: gossy@par.odn.ne.jp [Department of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu, 501-1194 (Japan); Kajita, Kimihiro [Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194 (Japan); Kawada, Hiroshi; Kawai, Nobuyuki; Koyasu, Hiromi; Matsuo, Masayuki [Department of Radiology, Gifu University Hospital, 1-1 Yanagido, Gifu, 501-1194 (Japan); Bae, Kyongtae T. [Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA (United States)

2016-11-15

Purpose: To evaluate the association between gadoxetic-acid-enhanced magnetic resonance (MR) imaging measurements and laboratory and clinical biomarkers of liver function and fibrosis. Materials and methods: One hundred thirty nine consecutive patients with suspected liver disease or liver tumor underwent gadoxetic-acid-enhanced MR imaging. MR imaging measurements during the hepatobiliary phase included biliary tract structure-to-muscle signal intensity ratio (SIR). These measurements were compared with Child-Pugh classification, end-stage liver disease (MELD) score, and aspartate aminotransferase-to-platelet ratio index (APRI). Results: The SIRs of cystic duct and common bile duct were significantly correlated with Child-Pugh classification (P = 0.012 for cystic duct and P < 0.0001 for common bile duct), MELD score (P = 0.0016 and P = 0.0033), and APRI (P = 0.0022 and P = 0.0015). The sensitivity, specificity, and area under the receiver-operating-characteristic curve were: (74%, 88%, 0.86) with the SIR of common bile duct for the detection of patients with Child-Pugh class B or C; (100%, 87%, 0.94) with the SIR of cystic duct for MELD score (>10); (65%, 76%, 0.70) with the SIR of common bile duct for APRI (>1.5). Conclusion: Gadoxetic-acid contrast enhancement of cystic duct and common bile duct could be used as biomarkers to assess liver function.

Natural Arabidopsis brx loss-of-function alleles confer root adaptation to acidic soil.

Science.gov (United States)

Gujas, Bojan; Alonso-Blanco, Carlos; Hardtke, Christian S

2012-10-23

Soil acidification is a major agricultural problem that negatively affects crop yield. Root systems counteract detrimental passive proton influx from acidic soil through increased proton pumping into the apoplast, which is presumably also required for cell elongation and stimulated by auxin. Here, we found an unexpected impact of extracellular pH on auxin activity and cell proliferation rate in the root meristem of two Arabidopsis mutants with impaired auxin perception, axr3 and brx. Surprisingly, neutral to slightly alkaline media rescued their severely reduced root (meristem) growth by stimulating auxin signaling, independent of auxin uptake. The finding that proton pumps are hyperactive in brx roots could explain this phenomenon and is consistent with more robust growth and increased fitness of brx mutants on overly acidic media or soil. Interestingly, the original brx allele was isolated from a natural stock center accession collected from acidic soil. Our discovery of a novel brx allele in accessions recently collected from another acidic sampling site demonstrates the existence of independently maintained brx loss-of-function alleles in nature and supports the notion that they are advantageous in acidic soil pH conditions, a finding that might be exploited for crop breeding. Copyright © 2012 Elsevier Ltd. All rights reserved.

Investigation of the adsorption of amino acids on Pd(1 1 1): A density functional theory study

International Nuclear Information System (INIS)

James, Joanna N.; Han, Jeong Woo; Sholl, David S.

2014-01-01

Graphical abstract: - Highlights: • Density functional theory calculations have been performed to study the adsorption of glycine, alanine, norvaline, valine, proline, cysteine, and serine on Pd(1 1 1). • The common structural framework for the adsorption of most amino acids onto Pd(1 1 1) is in a tridentate fashion via a nitrogen atom and two oxygen atoms. • The shifts in vibrational frequencies associated with NHH and COO support the adsorption patterns of amino acids we examined. • The adsorption strength of amino acids depends on how much the molecules deform during the adsorption process. - Abstract: Density functional theory calculations have been used to study the adsorption of glycine, alanine, norvaline, valine, proline, cysteine, and serine on Pd(1 1 1). Most amino acids except cysteine adsorb onto the surface in a tridentate fashion through a nitrogen atom and both oxygen atoms. For cysteine, an additional bond is formed with the surface due to the strong affinity of the sulfur atom, resulting in a significantly larger adsorption energy. The adsorption patterns of amino acids we examined are supported by the shifts in vibrational frequencies associated with NHH and COO. The adsorption strength of amino acids depends on how much the molecules deform during the adsorption process. Understanding the adsorption of amino acids on Pd(1 1 1) provides fundamental information for future consideration of the interactions between their derivatives or more complicated biomolecules and metal surfaces

Distinct functional domains within the acidic cluster of tegument protein pp28 required for trafficking and cytoplasmic envelopment of human cytomegalovirus.

Science.gov (United States)

Seo, Jun-Young; Jeon, Hyejin; Hong, Sookyung; Britt, William J

2016-10-01

Human cytomegalovirus UL99-encoded tegument protein pp28 contains a 16 aa acidic cluster that is required for pp28 trafficking to the assembly compartment (AC) and the virus assembly. However, functional signals within the acidic cluster of pp28 remain undefined. Here, we demonstrated that an acidic cluster rather than specific sorting signals was required for trafficking to the AC. Recombinant viruses with chimeric pp28 proteins expressing non-native acidic clusters exhibited delayed viral growth kinetics and decreased production of infectious virus, indicating that the native acidic cluster of pp28 was essential for wild-type virus assembly. These results suggested that the acidic cluster of pp28 has distinct functional domains required for trafficking and for efficient virus assembly. The first half (aa 44-50) of the acidic cluster was sufficient for pp28 trafficking, whereas the native acidic cluster consisting of aa 51-59 was required for the assembly of wild-type levels of infectious virus.

Chemical Transport Knockout for Oxidized Vitamin C, Dehydroascorbic Acid, Reveals Its Functions in vivo

Directory of Open Access Journals (Sweden)

Hongbin Tu

2017-09-01

Full Text Available Despite its transport by glucose transporters (GLUTs in vitro, it is unknown whether dehydroascorbic acid (oxidized vitamin C, DHA has any in vivo function. To investigate, we created a chemical transport knockout model using the vitamin C analog 6-bromo-ascorbate. This analog is transported on sodium-dependent vitamin C transporters but its oxidized form, 6-bromo-dehydroascorbic acid, is not transported by GLUTs. Mice (gulo−/− unable to synthesize ascorbate (vitamin C were raised on 6-bromo-ascorbate. Despite normal survival, centrifugation of blood produced hemolysis secondary to near absence of red blood cell (RBC ascorbate/6-bromo-ascorbate. Key findings with clinical implications were that RBCs in vitro transported dehydroascorbic acid but not bromo-dehydroascorbic acid; RBC ascorbate in vivo was obtained only via DHA transport; ascorbate via DHA transport in vivo was necessary for RBC structural integrity; and internal RBC ascorbate was essential to maintain ascorbate plasma concentrations in vitro/in vivo.

Aspartic acid

Science.gov (United States)

... we eat. Aspartic acid is also called asparaginic acid. Aspartic acid helps every cell in the body work. It ... release Normal nervous system function Plant sources of aspartic acid include: avocado, asparagus, and molasses. Animal sources of ...

α-Amino acid containing degradable polymers as functional biomaterials: rational design, synthetic pathway, and biomedical applications.

Science.gov (United States)

Sun, Huanli; Meng, Fenghua; Dias, Aylvin A; Hendriks, Marc; Feijen, Jan; Zhong, Zhiyuan

2011-06-13

Currently, biomedical engineering is rapidly expanding, especially in the areas of drug delivery, gene transfer, tissue engineering, and regenerative medicine. A prerequisite for further development is the design and synthesis of novel multifunctional biomaterials that are biocompatible and biologically active, are biodegradable with a controlled degradation rate, and have tunable mechanical properties. In the past decades, different types of α-amino acid-containing degradable polymers have been actively developed with the aim to obtain biomimicking functional biomaterials. The use of α-amino acids as building units for degradable polymers may offer several advantages: (i) imparting chemical functionality, such as hydroxyl, amine, carboxyl, and thiol groups, which not only results in improved hydrophilicity and possible interactions with proteins and genes, but also facilitates further modification with bioactive molecules (e.g., drugs or biological cues); (ii) possibly improving materials biological properties, including cell-materials interactions (e.g., cell adhesion, migration) and degradability; (iii) enhancing thermal and mechanical properties; and (iv) providing metabolizable building units/blocks. In this paper, recent developments in the field of α-amino acid-containing degradable polymers are reviewed. First, synthetic approaches to prepare α-amino acid-containing degradable polymers will be discussed. Subsequently, the biomedical applications of these polymers in areas such as drug delivery, gene delivery and tissue engineering will be reviewed. Finally, the future perspectives of α-amino acid-containing degradable polymers will be evaluated.

Peptic ulcer pathophysiology: acid, bicarbonate, and mucosal function

DEFF Research Database (Denmark)

Højgaard, L; Mertz Nielsen, A; Rune, S J

1996-01-01

The previously accepted role of gastric acid hypersecretion in peptic ulcer disease has been modified by studies showing no correlation between acid output and clinical outcome of ulcer disease, or between ulcer recurrence rate after vagotomy and preoperative acid secretion. At the same time......, studies have been unable to demonstrate increased acidity in the duodenal bulb in patients with duodenal ulcer, and consequently more emphasis has been given to the mucosal protecting mechanisms. The existence of an active gastric and duodenal mucosal bicarbonate secretion creates a pH gradient from...... cell removal and repair regulated by epidermal growth factor. Sufficient mucosal blood flow, including a normal acid/base balance, is important for subepithelial protection. In today's model of ulcer pathogenesis, gastric acid and H. pylori work in concert as aggressive factors, with the open question...

[Teichoic acids from lactic acid bacteria].

Science.gov (United States)

Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

2012-01-01

The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

Functionalized graphene with polymer toughener as novel interface modifier for property-tailored poly(lactic acid)/graphene nanocomposites

Science.gov (United States)

In this work, an effective strategy for engineering the interfacial compatibility between graphene and polylactic acid (PLA) was developed by manipulating the functionalization of graphene and introducing an epoxy-containing elastomer modifier. Curing between the functional groups of the modified gr...

Density functional theory study of acetic acid steam reforming on Ni(111)

Science.gov (United States)

Ran, Yan-Xiong; Du, Zhen-Yi; Guo, Yun-Peng; Feng, Jie; Li, Wen-Ying

2017-04-01

Catalytic steam reforming of bio-oil is a promising process to convert biomass into hydrogen. To shed light on this process, acetic acid is selected as the model compound of the oxygenates in bio-oil, and density functional theory is applied to investigate the mechanism of acetic acid steam reforming on the Ni(111) surface. The most favorable pathway of this process on the Ni(111) surface is suggested as CH3COOH* → CH3COO* → CH3CO* → CH2CO* → CH2* + CO* → CH* → CHOH* → CHO* → CO*, followed by the water gas shift reaction to produce CO2 and H2. CH* species are identified as the major carbon deposition precursor, and the water gas shift reaction is the rate-determining step during the whole acetic acid steam reforming process, as CO* + OH* → cis-COOH* is kinetically restricted with the highest barrier of 1.85 eV. Furthermore, the formation pathways and initial dissociation of important intermediates acetone and acetaldehyde are also investigated.

Silk amino acids improve physical stamina and male reproductive function of mice.

Science.gov (United States)

Shin, Sunhee; Yeon, Seongho; Park, Dongsun; Oh, Jiyoung; Kang, Hyomin; Kim, Sunghyun; Joo, Seong Soo; Lim, Woo-Taek; Lee, Jeong-Yong; Choi, Kyung-Chul; Kim, Ki Yon; Kim, Seung Up; Kim, Jong-Choon; Kim, Yun-Bae

2010-01-01

The effects of a silk amino acid (SAA) preparation on the physical stamina and male reproductive function of mice were investigated. Eight-week-old male ICR mice (29-31 g) were orally administered SAA (50, 160 or 500 mg/kg) for 44 d during 30-min daily swimming exercise. The mice were subjected to a weight-loaded (5% of body weight) forced swimming on the 14th, 28th and 42nd day to determine maximum swimming time, and after a 2-d recovery period (treated with SAA without swimming exercise), parameters related to fatigue and reproductive function were analyzed from blood, muscles and reproductive organs. Repeated swimming exercise increased the maximum swimming time to some extent, in spite of a marked reduction in body weight gain, and SAA further enhanced the stamina in a dose-dependent manner. Forced swimming exercises increased blood parameters of tissue injury, but depleted blood glucose and tissue glycogen, which were substantially prevented by SAA treatment. In addition, SAA significantly reduced the muscular thiobarbituric acid-reactive substances and blood corticosterone content increased by forced swimming. Swimming exercise decreased the blood testosterone level, which was recovered by SAA, leading to enhanced sperm counts. These combined results indicate that SAA not only enhances physical stamina by minimizing damage to tissues, including muscles, as well as preventing energy depletion caused by swimming stress, but also improves male reproductive function by increasing testosterone and sperm counts.

Nanocomposites of phosphonic-acid-functionalized polyethylenes with inorganic quantum dots.

Science.gov (United States)

Rünzi, Thomas; Baier, Moritz C; Negele, Carla; Krumova, Marina; Mecking, Stefan

2015-01-01

Insertion of diethyl vinyl phosphonates and free vinyl phosphonic acid, respectively, into [(P^O)Pd(Me)(dmso)] ((P^O) = κ(2)-P,O-Ar2PC6H4SO2O with Ar = 2-MeOC6H4) (1-dmso) occurs in a 2,1- as well as 1,2-fashion, to form a four-and a five-membered chelate [(P^O)Pd{κ(2)-C,O-CH(P(O)(OR)2)CH2CH3}] and [(P^O)Pd{κ(2)-C,O-CH2CH(P(O)(OR)2)CH3}] (R = H, Et). No decomposition or other reactions of 1 by free phosphonic acid moieties occur. Copolymerization in a pressure reactor by 1-dmso yields linear random poly(ethylene-co-diethyl vinyl phosphonate) and poly(ethylene-co-vinyl phosphonic acid). In these copolymerizations, reversible coordination of the phosphonate moieties of free monomer as well as chelate formation by incorporated monomer retards chain growth as also evidenced by relative binding studies of diethyl phosphonate towards 1. Post-polymerization emulsification of poly(ethylene-co-vinyl phosphonic acid) together with CdSe/CdS quantum dots (QDs) yields submicron (ca. 50 nm from dynamic light scattering (DLS) and transmission electron microscopy (TEM)) polymer particles with the QDs embedded in the functionalized polyethylene in a nonaggregated fashion. This embedding benefits the fluorescence behavior in terms of continuous emission and life-time as revealed by wide-field fluorescence measurements. These composite particle dispersions are employed as a ″masterbatch" together with an aqueous high density polyethylene (HDPE) dispersion to generate thin films (by spin-coating) and bulk materials (from the melt), respectively, in which the inorganic nanoparticles remain highly disperse. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

FabQ, a Dual-Function Dehydratase/Isomerase, Circumvents the Last Step of the Classical Fatty Acid Synthesis Cycle

OpenAIRE

Bi, Hongkai; Wang, Haihong; Cronan, John E.

2013-01-01

In the classical anaerobic pathway of unsaturated fatty acid biosynthesis, that of Escherichia coli, the double bond is introduced into the growing acyl chain by the FabA dehydratase/isomerase. Another dehydratase, FabZ, functions in the chain elongation cycle. In contrast, Aerococcus viridans has only a single FabA/FabZ homolog we designate FabQ. FabQ can not only replace the function of E. coli FabZ in vivo, but it also catalyzes the isomerization required for unsaturated fatty acid biosynt...

Synthesis of Molecularly Imprinted Polymers for Amino Acid Derivates by Using Different Functional Monomers

Directory of Open Access Journals (Sweden)

Sonia Scorrano

2011-03-01

Full Text Available Fmoc-3-nitrotyrosine (Fmoc-3-NT molecularly imprinted polymers (MIPs were synthesized to understand the influence of several functional monomers on the efficiency of the molecular imprinting process. Acidic, neutral and basic functional monomers, such as acrylic acid (AA, methacrylic acid (MAA, methacrylamide (MAM, 2-vinylpyridine (2-VP, 4-vinylpyridine (4-VP, have been used to synthesize five different polymers. In this study, the MIPs were tested in batch experiments by UV-visible spectroscopy in order to evaluate their binding properties. The MIP prepared with 2-VP exhibited the highest binding affinity for Fmoc-3NT, for which Scatchard analysis the highest association constant (2.49 × 104 M−1 was obtained. Furthermore, titration experiments of Fmoc-3NT into acetonitrile solutions of 2-VP revealed a stronger bond to the template, such that a total interaction is observed. Non-imprinted polymers as control were prepared and showed no binding affinities for Fmoc-3NT. The results are indicative of the importance of ionic bonds formed between the –OH residues of the template molecule and the pyridinyl groups of the polymer matrix. In conclusion, 2-VP assists to create a cavity which allows better access to the analytes.

Structural and thermal properties of carboxylic acid functionalized polythiophenes

Directory of Open Access Journals (Sweden)

Ariane de França Mescoloto

2014-01-01

Full Text Available Polythiophenes functionalized with polar groups at the end of side-chain have emerged as an alternative method to obtain good compatibility between this class of conjugated polymers and electron acceptor compounds. The aim is to prevent phase segregation and to improve the efficiency of the polythiophene technological devices. However, homopolymers synthesized from thiophene rings with high polar groups at the end of the side-chain, such as hydroxyl and carboxylic acid groups, are poorly soluble in common volatile organic solvents. We report on a systematic preparation of copolymers of 3-hexylthiophene (HT and thiophene-3-acetic acid (TAA, using different feed ratios. The chemical structures of the copolymers were confirmed by FTIR and ¹H-NMR. The TAA content in these copolymers were 33, 38 and 54 mol %. HPSEC results did not show any remarkable correlation with TAA contents in the copolymers. In contrast, the thermal analyses showed a decrease in the thermal stability and an increase in rigidity of their backbones, for the copolymers with high amounts of TAA. The solubility and optical property of copolymers were also related to the TAA contents. Thus, the properties of these copolymers can be modulated by a simple control of feed ratio of TAA in the copolymerization.

Radiation curable coatings containing hydroxy functional polyethers and polyesters of monoethylenic acids or hydroxy esters thereof

International Nuclear Information System (INIS)

Kaufman, M.L.

1978-01-01

Relatively water insoluble hydroxy functional monoethylenic polyethers or polyesters of monoethylenic carboxylic acids or hydroxy alkyl esters thereof are formed by adducting the monoethylenic acid or its hydroxy ester with an anhydride selected from monoepoxides, lactones, or mixtures thereof in the presence of a Lewis acid catalyst, such as BF 3 etherate, at a temperature below that at which the unsaturation is consumed, typically about 30 to 70 0 C. These adducts are of low volatility and of low toxicity and can be radiation cured in admixture with polyacrylates to form coatings having improved resistance to elevated temperature exposure

Docosahexaenoic acid (DHA, an essential fatty acid for the proper functioning of neuronal cells: their role in mood disorders

Directory of Open Access Journals (Sweden)

2009-06-01

Full Text Available The brain and the nervous system are tissues with high contents of two polyunsaturated fatty acids: arachidonic acid (20:4, omega-6, AA and docosahexaenoic acid (22:6, omega-3, DHA. Despite their abundance in these tissues, AA and DHA cannot be re-synthesized in mammals. However, the concentration of these fatty acids can be modulated by dietary intake. AA and DHA must be provided by the diet as such (preformed or through the respective omega-6 and omega-3 precursors from vegetable origin. Linoleic acid, the precursor of AA is very abundant in the western diet and therefore the formation of AA from linoleic acid is not restrictive. On the other hand, alpha linolenic acid, the precursor of DHA is less available in our diet and preformed DHA is highly restrictive in some populations. During the last period of gestation and during the early post natal period, neurodevelopment occurs exceptionally quickly, and significant amounts of omega-6 and omega-3 polyunsaturated fatty acids, especially DHA, are critical to allow neurite outgrowth and the proper brain and retina development and function. In this review various functions of DHA in the nervous system, its metabolism into phospholipids, and its involvement in different neurological and mood disorders, such as Alzheimer’s disease, depression, and others are revised.

El cerebro y el sistema nervioso son tejidos con un alto contenido de dos ácidos grasos poliinsaturados: el ácido araquidónico (20:4, omega-6, AA y el ácido docosahexaenoico (22:6, omega-3, DHA. A pesar de la abundancia de estos ácidos grasos en dichos tejidos los mamíferos no los pueden sintetizar de novo. Sin embargo, la concentración de estos ácidos grasos puede ser modificada por la dieta. El AA y el DHA pueden ser aportados por la dieta como tales (preformados o a partir de los respectivos precursores de origen vegetal. El ácido linoleico, precursor del AA es muy abundante en la dieta occidental, por lo cual la

Functionalization of glassy carbon surface by means of aliphatic and aromatic amino acids. An experimental and theoretical integrated approach

International Nuclear Information System (INIS)

Vanossi, Davide; Benassi, Rois; Parenti, Francesca; Tassinari, Francesco; Giovanardi, Roberto; Florini, Nicola; De Renzi, Valentina; Arnaud, Gaelle; Fontanesi, Claudio

2012-01-01

Highlights: ► Glassy carbon is functionalized via electrochemical assisted grafting of amino acids. ► The grafting mechanism is suggested to involve the “zwitterionic” species. ► DFT calculations allowed to determine the electroactive species. ► An original grafting mechanism is proposed. - Abstract: Glassy carbon (GC) electrode surfaces are functionalized through electrochemical assisted grafting, in oxidation regime, of six amino acids (AA): β-alanine (β-Ala), L-aspartic acid (Asp), 11-aminoundecanoic acid (UA), 4-aminobenzoic acid (PABA), 4-(4-amino-phenyl)-butyric acid (PFB), 3-(4-amino-phenyl)-propionic acid (PFP). Thus, a GC/AA interface is produced featuring carboxylic groups facing the solution. Electrochemical (cyclic voltammetry and electrochemical impedance spectroscopy) and XPS techniques are used to experimentally characterize the grafting process and the surface state. The theoretical results are compared with the experimental evidence to determine, at a molecular level, the overall grafting mechanism. Ionization potentials, standard oxidation potentials, HOMO and electron spin distributions are calculated at the CCD/6-31G* level of the theory. The comparison of experimental and theoretical data suggests that the main electroactive species is the “zwitterionic” form for the three aliphatic amino acids, while the amino acids featuring the amino group bound to the phenyl aromatic moiety show a different behaviour. The comparison between experimental and theoretical results suggests that both the neutral and the zwitterionic forms are present in the acetonitrile solution in the case of 4-(4-amino-phenyl)-butyric acid (PFB) and 3-(4-amino-phenyl)-propionic acid.

α,β-Unsaturated monoterpene acid glucose esters: structural diversity, bioactivities and functional roles.

Science.gov (United States)

Goodger, Jason Q D; Woodrow, Ian E

2011-12-01

The glycosylation of lipophilic small molecules produces many important plant secondary metabolites. The majority of these are O-glycosides with relatively fewer occurring as glucose esters of aromatic or aliphatic acids. In particular, monoterpene acid glucose esters have much lower structural diversity and distribution compared to monoterpene glycosides. Nevertheless, there have been over 20 monoterpene acid glucose esters described from trees in the genus Eucalyptus (Myrtaceae) in recent years, all based on oleuropeic acid, menthiafolic acid or both. Here we review all of the glucose esters containing these monoterpenoids identified in plants to date. Many of the compounds contain phenolic aglycones and all contain at least one α,β-unsaturated carbonyl, affording a number of important potential therapeutic reactivities such as anti-tumor promotion, carcinogenesis suppression, and anti-oxidant and anti-inflammatory activities. Additional properties such as cytotoxicity, bitterness, and repellency are suggestive of a role in plant defence, but we also discuss their localization to the exterior of foliar secretory cavity lumina, and suggest they may also protect secretory cells from toxic terpenes housed within these structures. Finally we discuss how the use of a recently developed protocol to isolate secretory cavities in a functional state could be used in conjunction with systems biology approaches to help characterize their biosynthesis and roles in plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

Naked mole-rat acid-sensing ion channel 3 forms nonfunctional homomers, but functional heteromers.

Science.gov (United States)

Schuhmacher, Laura-Nadine; Callejo, Gerard; Srivats, Shyam; Smith, Ewan St John

2018-02-02

Acid-sensing ion channels (ASICs) form both homotrimeric and heterotrimeric ion channels that are activated by extracellular protons and are involved in a wide range of physiological and pathophysiological processes, including pain and anxiety. ASIC proteins can form both homotrimeric and heterotrimeric ion channels. The ASIC3 subunit has been shown to be of particular importance in the peripheral nervous system with pharmacological and genetic manipulations demonstrating a role in pain. Naked mole-rats, despite having functional ASICs, are insensitive to acid as a noxious stimulus and show diminished avoidance of acidic fumes, ammonia, and carbon dioxide. Here we cloned naked mole-rat ASIC3 (nmrASIC3) and used a cell-surface biotinylation assay to demonstrate that it traffics to the plasma membrane, but using whole-cell patch clamp electrophysiology we observed that nmrASIC3 is insensitive to both protons and the non-proton ASIC3 agonist 2-guanidine-4-methylquinazoline. However, in line with previous reports of ASIC3 mRNA expression in dorsal root ganglia neurons, we found that the ASIC3 antagonist APETx2 reversibly inhibits ASIC-like currents in naked mole-rat dorsal root ganglia neurons. We further show that like the proton-insensitive ASIC2b and ASIC4, nmrASIC3 forms functional, proton-sensitive heteromers with other ASIC subunits. An amino acid alignment of ASIC3s between 9 relevant rodent species and human identified unique sequence differences that might underlie the proton insensitivity of nmrASIC3. However, introducing nmrASIC3 differences into rat ASIC3 (rASIC3) produced only minor differences in channel function, and replacing the nmrASIC3 sequence with that of rASIC3 did not produce a proton-sensitive ion channel. Our observation that nmrASIC3 forms nonfunctional homomers may reflect a further adaptation of the naked mole-rat to living in an environment with high-carbon dioxide levels. © 2018 by The American Society for Biochemistry and Molecular

A safer and flexible method for the oxygen functionalization of carbon nanotubes by nitric acid vapors

International Nuclear Information System (INIS)

Santangelo, Saveria; Piperopoulos, Elpida; Fazio, Enza; Faggio, Giuliana; Ansari, Shabana; Lanza, Maurizio; Neri, Fortunato; Messina, Giacomo; Milone, Candida

2014-01-01

The functionalization by nitric acid vapors at azeotropic concentration has been recently proposed to eliminate drawbacks of the widely utilized liquid phase functionalization method. This work suggests to exploit the so-called “salt effect” to improve the vapor phase oxidation method in terms of safety and flexibility. Increasing the relative volatility of acid, the addition of Mg(NO 3 ) 2 salt to the HNO 3 + H 2 O solution allows (i) obtaining vapors with HNO 3 at the azeotropic concentration from a more diluted liquid solution (i.e. operating under safer conditions), and (ii) varying the concentration of HNO 3 in the vapor phase even above the azeotropic concentration limit (with improved process flexibility). High-resolution transmission electron microscopy, thermo-gravimetry, Raman spectroscopy and X-ray photoemission spectroscopy systematic analyses are carried out on pristine and oxidized nanotubes in order to assess their functionalization degree, surface chemistry and structural evolution. The most relevant finding of this preliminary study is that the nanotube functionalization extent increases linearly with the HNO 3 vapor concentration.

A safer and flexible method for the oxygen functionalization of carbon nanotubes by nitric acid vapors

Energy Technology Data Exchange (ETDEWEB)

Santangelo, Saveria, E-mail: saveria.santangelo@unirc.it [Dipartimento di Ingegneria Civile, dell’Energia, dell’Ambiente e dei Materiali (DICEAM), Università “Mediterranea”, 89122 Reggio Calabria (Italy); Piperopoulos, Elpida [Dipartimento di Ingegneria Eletronica, Chimica ed Ingegneria Industriale (DIECII), Università di Messina, 98166 Messina (Italy); Fazio, Enza [Dipartimento di Fisica e di Scienze della Terra (DFST), Università di Messina, 98166 Messina (Italy); Faggio, Giuliana [Dipartimento di Ingegneria dell’Informazione, delle Infrastrutture e dell’Energia Sostenibile (DIIES), Università “Mediterranea”, 89122 Reggio Calabria (Italy); Ansari, Shabana [Dipartimento di Ingegneria Eletronica, Chimica ed Ingegneria Industriale (DIECII), Università di Messina, 98166 Messina (Italy); Lanza, Maurizio [Istituto per i Processi Chimico Fisici (IPCF) del CNR, 98158 Messina (Italy); Neri, Fortunato [Dipartimento di Fisica e di Scienze della Terra (DFST), Università di Messina, 98166 Messina (Italy); Messina, Giacomo [Dipartimento di Ingegneria dell’Informazione, delle Infrastrutture e dell’Energia Sostenibile (DIIES), Università “Mediterranea”, 89122 Reggio Calabria (Italy); Milone, Candida [Dipartimento di Ingegneria Eletronica, Chimica ed Ingegneria Industriale (DIECII), Università di Messina, 98166 Messina (Italy)

2014-06-01

The functionalization by nitric acid vapors at azeotropic concentration has been recently proposed to eliminate drawbacks of the widely utilized liquid phase functionalization method. This work suggests to exploit the so-called “salt effect” to improve the vapor phase oxidation method in terms of safety and flexibility. Increasing the relative volatility of acid, the addition of Mg(NO{sub 3}){sub 2} salt to the HNO{sub 3} + H{sub 2}O solution allows (i) obtaining vapors with HNO{sub 3} at the azeotropic concentration from a more diluted liquid solution (i.e. operating under safer conditions), and (ii) varying the concentration of HNO{sub 3} in the vapor phase even above the azeotropic concentration limit (with improved process flexibility). High-resolution transmission electron microscopy, thermo-gravimetry, Raman spectroscopy and X-ray photoemission spectroscopy systematic analyses are carried out on pristine and oxidized nanotubes in order to assess their functionalization degree, surface chemistry and structural evolution. The most relevant finding of this preliminary study is that the nanotube functionalization extent increases linearly with the HNO{sub 3} vapor concentration.

Differences in functional traits between invasive and native Amaranthus species under simulated acid deposition with a gradient of pH levels

Science.gov (United States)

Wang, Congyan; Wu, Bingde; Jiang, Kun; Zhou, Jiawei

2018-05-01

Co-occurring invasive plant species (invaders hereafter) and natives receive similar or even the same environmental selection pressures. Thus, the differences in functional traits between natives and invaders have become widely recognized as a major driving force of the success of plant invasion. Meanwhile, increasing amounts of acid are deposited into ecosystems. Thus, it is important to elucidate the potential effects of acid deposition on the functional traits of invaders in order to better understand the potential mechanisms for the successful invasion. This study aims to address the differences in functional traits between native red amaranth (Amaranthus tricolor L.; amaranth hereafter) and invasive redroot pigweed (A. retroflexus L.; pigweed hereafter) under simulated acid deposition with a gradient of pH levels. Pigweed was significantly taller than amaranth under most treatments. The greater height of pigweed can lead to greater competitive ability for resource acquisition, particularly for sunlight. Leaf shape index of pigweed was also significantly greater than that of amaranth under all treatments. The greater leaf shape index of pigweed can enhance the efficiency of resource capture (especially sunlight capture) via adjustments to leaf shape and size. Thus, the greater height and leaf shape index of pigweed can significantly enhance its competitive ability, especially under acid deposition. Acid deposition of pH 5.6 significantly increased amaranth leaf width in the co-cultivation due to added nutrients. The pH 4.5 acid deposition treatment significantly increased the specific leaf area of amaranth in the monoculture compared with the pH 5.6 acid deposition treatment and the control. The main mechanism explaining this pattern may be due to acid deposition mediating a hormesis effect on plants, promoting plant growth. The values of the relative competition intensity between amaranth and pigweed for most functional traits were lower than zero under most

Functional Properties and Amino Acid Profile of Spirulina Platensis Protein Isolates

International Nuclear Information System (INIS)

Bashir, S.; Sharif, M. K.; Butt, M. S.; Shahid, M.

2016-01-01

Protein malnutrition and food insecurity represent serious obstructions to sustainable development, poverty reduction and food quality throughout the world. The present study has been designed to evaluate the Spirulina platensis (SP) as a protein alternative source for the utilization in food products. A protein isolate was prepared from S. platensis powder through extraction with 0.1N NaOH, precipitation at pH 3, neutralization of the dispersed precipitate to pH 6.8-7.0, and subsequent freeze drying. The S. platensis isolate amino acids compositions revealed that the total essential amino acids contribution was comparatively higher in SPI (31.16±1.43 g/100 g) as compared with SP (27.75±1.21 g/100 g). Moreover, oil and water absorption capacities, foaming and emulsifying properties, surface hydrophobicity and nitrogen solubility index were found better functional properties under laboratory conditions except emulsion properties. Conclusively, SP and its isolates might be used in various food products to curtail protein energy malnutrition. (author)

Mechanistic investigation of the one-pot formation of amides by oxidative coupling of alcohols with amines in methanol

DEFF Research Database (Denmark)

Mielby, Jerrik Jørgen; Riisager, Anders; Fristrup, Peter

2013-01-01

The one-pot formation of amides by oxidative coupling of alcohols and amines via intermediate formation of methyl ester using supported gold and base as catalysts was studied using the Hammett methodology. Determining the relative reactivity of four different para-substituted benzyl alcohol deriv...... a theoretical Hammett plot that was in good agreement with the one obtained experimentally....

Application of functionalized lanthanide-based nanoparticles for the detection of okadaic acid-specific immunoglobulin G.

Science.gov (United States)

Stipić, Filip; Pletikapić, Galja; Jakšić, Željko; Frkanec, Leo; Zgrablić, Goran; Burić, Petra; Lyons, Daniel M

2015-01-29

Marine biotoxins are widespread in the environment and impact human health via contaminated shellfish, causing diarrhetic, amnesic, paralytic, or neurotoxic poisoning. In spite of this, methods for determining if poisoning has occurred are limited. We show the development of a simple and sensitive luminescence resonance energy transfer (LRET)-based concept which allows the detection of anti-okadaic acid rabbit polyclonal IgG (mouse monoclonal IgG1) using functionalized lanthanide-based nanoparticles. Upon UV excitation, the functionalized nanoparticles were shown to undergo LRET with fluorophore-labeled anti-okadaic acid antibodies which had been captured and bound by okadaic acid-decorated nanoparticles. The linear dependence of fluorescence emission intensity with antigen-antibody binding events was recorded in the nanomolar to micromolar range, while essentially no LRET signal was detected in the absence of antibody. These results may find applications in new, cheap, and robust sensors for detecting not only immune responses to biotoxins but also a wide range of biomolecules based on antigen-antibody recognition systems. Further, as the system is based on solution chemistry it may be sufficiently simple and versatile to be applied at point-of-care.

Effects of gamma-aminobutyric acid (GABA) on synaptogenesis and synaptic function

DEFF Research Database (Denmark)

Belhage, B; Hansen, G H; Elster, L

1998-01-01

The correct establishment and function of synapses depend on a variety of factors, such as guidance of pre- and postsynaptic neurons as well as receptor development and localization. gamma-Aminobutyric acid (GABA) has a pronounced effect on these events and elicits differentiation of neurons......; that is, GABA acts as a trophic signal. Accordingly, activating preexisting GABA receptors, a trophic GABA signal enhances the growth rate of neuronal processes, facilitates synapse formation, and promotes synthesis of specific proteins. Transcription and de novo synthesis are initiated by the GABA signal......, but the intracellular link between GABA receptor activation and DNA transcription is largely unknown. GABA also controls the induction and development of functionally and pharmacologically different GABAA receptor subtypes. The induced receptors are likely to be inserted only into the synaptic membrane domain. However...

Density Functional Theory Study of Leaching Performance of Different Acids on Pyrochlore (100) Surface

Science.gov (United States)

Yang, Xiuli; Fang, Qing; Ouyang, Hui

2018-06-01

Pyrochlore leaching using hydrofluoric, sulfuric, and hydrochloric acids has been studied via experimental methods for years, but the interactions between niobium atoms on the pyrochlore surface and different acids have not been investigated. In this work, first-principles calculations based on density functional theory were used to elucidate the leaching performance of these three acids from the viewpoint of geometrical and electronic structures. The calculation results indicate that sulfate, chloride, and fluoride anions influence the geometric structure of pyrochlore (100) to different extents, decreasing in the order: sulfate, fluoride, chloride. Orbitals of O1 and O2 atoms of sulfate hybridized with those of surface niobium atom. Fluorine orbitals hybridized with those of surface niobium atoms. However, no obvious overlap exists between any orbitals of chlorine and surface niobium, revealing that chlorine does not interact chemically with surface niobium atoms.

Novel metabolic and physiological functions of branched chain amino acids: a review

Institute of Scientific and Technical Information of China (English)

Shihai Zhang; Xiangfang Zeng; Man Ren; Xiangbing Mao; Shiyan Qiao

2017-01-01

It is widely known that branched chain amino acids (BCAA) are not only elementary components for building muscle tissue but also participate in increasing protein synthesis in animals and humans.BCAA (isoleucine,leucine and valine) regulate many key signaling pathways,the most classic of which is the activation of the mTOR signaling pathway.This signaling pathway connects many diverse physiological and metabolic roles.Recent years have witnessed many striking developments in determining the novel functions of BCAA including:(1) Insufficient or excessive levels of BCAA in the diet enhances lipolysis.(2) BCAA,especially isoleucine,play a major role in enhancing glucose consumption and utilization by up-regulating intestinal and muscular glucose transporters.(3)Supplementation of leucine in the diet enhances meat quality in finishing pigs.(4) BCAA are beneficial for mammary health,milk quality and embryo growth.(5) BCAA enhance intestinal development,intestinal amino acid transportation and mucin production.(6) BCAA participate in up-regulating innate and adaptive immune responses.In addition,abnormally elevated BCAA levels in the blood (decreased BCAA catabolism) are a good biomarker for the early detection of obesity,diabetes and other metabolic diseases.This review will provide some insights into these novel metabolic and physiological functions of BCAA.

Novel metabolic and physiological functions of branched chain amino acids: a review.

Science.gov (United States)

Zhang, Shihai; Zeng, Xiangfang; Ren, Man; Mao, Xiangbing; Qiao, Shiyan

2017-01-01

It is widely known that branched chain amino acids (BCAA) are not only elementary components for building muscle tissue but also participate in increasing protein synthesis in animals and humans. BCAA (isoleucine, leucine and valine) regulate many key signaling pathways, the most classic of which is the activation of the mTOR signaling pathway. This signaling pathway connects many diverse physiological and metabolic roles. Recent years have witnessed many striking developments in determining the novel functions of BCAA including: (1) Insufficient or excessive levels of BCAA in the diet enhances lipolysis. (2) BCAA, especially isoleucine, play a major role in enhancing glucose consumption and utilization by up-regulating intestinal and muscular glucose transporters. (3) Supplementation of leucine in the diet enhances meat quality in finishing pigs. (4) BCAA are beneficial for mammary health, milk quality and embryo growth. (5) BCAA enhance intestinal development, intestinal amino acid transportation and mucin production. (6) BCAA participate in up-regulating innate and adaptive immune responses. In addition, abnormally elevated BCAA levels in the blood (decreased BCAA catabolism) are a good biomarker for the early detection of obesity, diabetes and other metabolic diseases. This review will provide some insights into these novel metabolic and physiological functions of BCAA.

Nb-Based Zeolites: Efficient bi-Functional Catalysts for the One-Pot Synthesis of Succinic Acid from Glucose

Directory of Open Access Journals (Sweden)

Magdi El Fergani

2017-12-01

Full Text Available The one-pot production of succinic acid from glucose was investigated in pure hot water as solvent using Nb (0.02 and 0.05 moles%-Beta zeolites obtained by a post-synthesis methodology. Structurally, they are comprised of residual framework Al-acid sites, extra-framework isolated Nb (V and Nb2O5 pore-encapsulated clusters. The Nb-modified Beta-zeolites acted as bi-functional catalysts in which glucose is dehydrated to levulinic acid (LA which, further, suffers an oxidation process to succinic acid (SA. After the optimization of the reaction conditions, that is, at 180 °C, 18 bar O2, and 12 h reaction time, the oxidation of glucose occurred with a selectivity to succinic acid as high as 84% for a total conversion.

TECHNOLOGICAL AND FUNCTIONAL PROPERTIES OF LACTIC ACID BACTERIA: THE IMPORTANCE OF THESE MICROORGANISMS FOR FOOD

Directory of Open Access Journals (Sweden)

Amanda de Souza Motta

2015-12-01

Full Text Available Eacters of coccus or rods Gram-positive, catalase negative, non-sporulating, which produce lactic acid as the major end product during the fermentation of carbohydrates. When applied on food, provides beneficial effects to consumers through its functional and technological properties. With this the present review article, explore the potential application of lactic acid bacteria in food. The following genera are considered the principal lactic acid bacteria: Aerococcus, Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus, Tetragenococcus, Vagococcus and Weissella. These cultures have been used as starter or adjunct cultures for the fermentation of foods and beverages due to their contributions to the sensorial characteristics of these products and by microbiological stability. Their probiotic properties have also been investigated. More recent studies by indigenous cultures have received increased attention in light of the search for isolated cultures of a given raw material and a certain region. These microorganisms are being investigated for its functional and technological potential that may be applied in product development with its own characteristics and designation of origin. Those properties will be discussed in the present review in order to highlight the performance of these bacteria and the high degree of control over the fermentation process and standardization of the final product. The use of autochthonous cultures will be considered due the increase of studies of new cultures of lactic acid bacteria isolated of milk and meat of distinct products.

Oral administration of eicosapentaenoic acid or docosahexaenoic acid modifies cardiac function and ameliorates congestive heart failure in male rats.

Science.gov (United States)

Yamanushi, Tomoko T; Kabuto, Hideaki; Hirakawa, Eiichiro; Janjua, Najma; Takayama, Fusako; Mankura, Mitsumasa

2014-04-01

This study assessed the effects of eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) on normal cardiac function (part 1) and congestive heart failure (CHF) (part 2) through electrocardiogram analysis and determination of EPA, DHA, and arachidonic acid (AA) concentrations in rat hearts. In part 2, pathologic assessments were also performed. For part 1 of this study, 4-wk-old male rats were divided into a control group and 2 experimental groups. The rats daily were orally administered (1 g/kg body weight) saline, EPA-ethyl ester (EPA-Et; E group), or DHA-ethyl ester (DHA-Et; D group), respectively, for 28 d. ECGs revealed that QT intervals were significantly shorter for groups E and D compared with the control group (P ≤ 0.05). Relative to the control group, the concentration of EPA was higher in the E group and concentrations of EPA and DHA were higher in the D group, although AA concentrations were lower (P ≤ 0.05). In part 2, CHF was produced by subcutaneous injection of monocrotaline into 5-wk-old rats. At 3 d before monocrotaline injection, rats were administered either saline, EPA-Et, or DHA-Et as mentioned above and then killed at 21 d. The study groups were as follows: normal + saline (control), CHF + saline (H group), CHF + EPA-Et (HE group), and CHF + DHA-Et (HD group). QT intervals were significantly shorter (P ≤ 0.05) in the control and HD groups compared with the H and HE groups. Relative to the H group, concentrations of EPA were higher in the HE group and those of DHA were higher in the control and HD groups (P ≤ 0.05). There was less mononuclear cell infiltration in the myocytes of the HD group than in the H group (P = 0.06). The right ventricles in the H, HE, and HD groups showed significantly increased weights (P ≤ 0.05) compared with controls. The administration of EPA-Et or DHA-Et may affect cardiac function by modification of heart fatty acid composition, and the administration of DHA-Et may ameliorate CHF.

Phosphorescence Imaging of Living Cells with Amino Acid-Functionalized Tris(2-phenylpyridine)iridium(III) Complexes

NARCIS (Netherlands)

Steunenberg, P.; Ruggi, A.; Berg, van den N.S.; Buckle, T.; Kuil, J.; Leeuwen, van F.W.B.; Velders, A.H.

2012-01-01

A series of nine luminescent cyclometalated octahedral iridium(III) tris(2-phenylpyridine) complexes has been synthesized, functionalized with three different amino acids (glycine, alanine, and lysine), on one, two, or all three of the phenylpyridine ligands. All starting complexes and final

Endocrine functions of bile acids

NARCIS (Netherlands)

Houten, Sander M.; Watanabe, Mitsuhiro; Auwerx, Johan

2006-01-01

Bile acids (BAs), a group of structurally diverse molecules that are primarily synthesized in the liver from cholesterol, are the chief components of bile. Besides their well-established roles in dietary lipid absorption and cholesterol homeostasis, it has recently emerged that BAs are also

D-Amino acid oxidase bio-functionalized platforms: Toward an enhanced enzymatic bio-activity

Science.gov (United States)

Herrera, Elisa; Valdez Taubas, Javier; Giacomelli, Carla E.

2015-11-01

The purpose of this work is to study the adsorption process and surface bio-activity of His-tagged D-amino acid oxidase (DAAO) from Rhodotorula gracilis (His6-RgDAAO) as the first step for the development of an electrochemical bio-functionalized platform. With such a purpose this work comprises: (a) the His6-RgDAAO bio-activity in solution determined by amperometry, (b) the adsorption mechanism of His6-RgDAAO on bare gold and carboxylated modified substrates in the absence (substrate/COO-) and presence of Ni(II) (substrate/COO- + Ni(II)) determined by reflectometry, and (c) the bio-activity of the His6-RgDAAO bio-functionalized platforms determined by amperometry. Comparing the adsorption behavior and bio-activity of His6-RgDAAO on these different solid substrates allows understanding the contribution of the diverse interactions responsible for the platform performance. His6-RgDAAO enzymatic performance in solution is highly improved when compared to the previously used pig kidney (pk) DAAO. His6-RgDAAO exhibits an amperometrically detectable bio-activity at concentrations as low as those expected on a bio-functional platform; hence, it is a viable bio-recognition element of D-amino acids to be coupled to electrochemical platforms. Moreover, His6-RgDAAO bio-functionalized platforms exhibit a higher surface activity than pkDAAO physically adsorbed on gold. The platform built on Ni(II) modified substrates present enhanced bio-activity because the surface complexes histidine-Ni(II) provide with site-oriented, native-like enzymes. The adsorption mechanism responsible of the excellent performance of the bio-functionalized platform takes place in two steps involving electrostatic and bio-affinity interactions whose prevalence depends on the degree of surface coverage.

Esophageal acid sensitivity and mucosal integrity in patients with functional heartburn.

Science.gov (United States)

Weijenborg, P W; Smout, A J P M; Bredenoord, A J

2016-11-01

Patients with functional heartburn (FH) experience troublesome heartburn that is not related to gastroesophageal reflux. The etiology of the heartburn sensation in FH patients is unknown. In patients with reflux disease, esophageal hypersensitivity seems associated with impaired mucosal integrity. We aimed to determine esophageal sensitivity and mucosal integrity in FH and non-erosive reflux disease (NERD) patients. In this prospective experimental study, we performed an acid perfusion test and upper endoscopy with biopsies in 12 patients with NERD and nine patients with FH. Mucosal integrity was measured during endoscopy using electrical tissue impedance spectroscopy and biopsy specimens were analyzed in Ussing chambers for transepithelial electrical resistance and transepithelial permeability. Lag time to heartburn perception was significantly longer in FH patients (median 12 min) than in NERD patients (median 3 min). Once perceived, intensity of heartburn was scored equal with median visual analog scale 6.5 and 7.1 respectively. Esophageal mucosal integrity was also comparable between FH and NERD patients, both in vivo extracellular impedance and ex vivo transepithelial resistance and permeability were similar. Patients with FH did not show acid hypersensitivity as seen in patients with NERD. However, once perceived, intensity of heartburn is similar. Esophageal mucosal integrity is similar between NERD and FH patients, and is therefore unlikely to be the underlying cause of the observed difference in esophageal acid perception. © 2016 John Wiley & Sons Ltd.

EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and gamma-linolenic acid (GLA) and contribution to normal cognitive function (ID 532) and maintenance

DEFF Research Database (Denmark)

Tetens, Inge

claims in relation to docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and gamma-linolenic acid (GLA) and contribution to normal cognitive function and maintenance of normal bone. The scientific substantiation is based on the information provided by the Member States in the consolidated list...... and fish oil”. From the references provided, the Panel assumes that the food constituents that are the subject of the claims are the n-6 fatty acid gamma-linolenic acid (GLA) in evening primrose oil and the n-3 long-chain polyunsaturated fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA...... of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders. The food constituents that are the subjects of the health claims are “omega-3 and omega-6 fatty acids (GLA)”, “gamma-linolenic acid + eicosapentaenoic acid (GLA+EPA)”, and “evening primrose oil...

Characterization of the mycobacterial acyl-CoA carboxylase holo complexes reveals their functional expansion into amino acid catabolism.

Directory of Open Access Journals (Sweden)

Matthias T Ehebauer

2015-02-01

Full Text Available Biotin-mediated carboxylation of short-chain fatty acid coenzyme A esters is a key step in lipid biosynthesis that is carried out by multienzyme complexes to extend fatty acids by one methylene group. Pathogenic mycobacteria have an unusually high redundancy of carboxyltransferase genes and biotin carboxylase genes, creating multiple combinations of protein/protein complexes of unknown overall composition and functional readout. By combining pull-down assays with mass spectrometry, we identified nine binary protein/protein interactions and four validated holo acyl-coenzyme A carboxylase complexes. We investigated one of these--the AccD1-AccA1 complex from Mycobacterium tuberculosis with hitherto unknown physiological function. Using genetics, metabolomics and biochemistry we found that this complex is involved in branched amino-acid catabolism with methylcrotonyl coenzyme A as the substrate. We then determined its overall architecture by electron microscopy and found it to be a four-layered dodecameric arrangement that matches the overall dimensions of a distantly related methylcrotonyl coenzyme A holo complex. Our data argue in favor of distinct structural requirements for biotin-mediated γ-carboxylation of α-β unsaturated acid esters and will advance the categorization of acyl-coenzyme A carboxylase complexes. Knowledge about the underlying structural/functional relationships will be crucial to make the target category amenable for future biomedical applications.

Effect of Strong Acid Functional Groups on Electrode Rise Potential in Capacitive Mixing by Double Layer Expansion

KAUST Repository

Hatzell, Marta C.

2014-12-02

© 2014 American Chemical Society. The amount of salinity-gradient energy that can be obtained through capacitive mixing based on double layer expansion depends on the extent the electric double layer (EDL) is altered in a low salt concentration (LC) electrolyte (e.g., river water). We show that the electrode-rise potential, which is a measure of the EDL perturbation process, was significantly (P = 10^-5) correlated to the concentration of strong acid surface functional groups using five types of activated carbon. Electrodes with the lowest concentration of strong acids (0.05 mmol g^-1) had a positive rise potential of 59 ± 4 mV in the LC solution, whereas the carbon with the highest concentration (0.36 mmol g^-1) had a negative rise potential (-31 ± 5 mV). Chemical oxidation of a carbon (YP50) using nitric acid decreased the electrode rise potential from 46 ± 2 mV (unaltered) to -6 ± 0.5 mV (oxidized), producing a whole cell potential (53 ± 1.7 mV) that was 4.4 times larger than that obtained with identical electrode materials (from 12 ± 1 mV). Changes in the EDL were linked to the behavior of specific ions in a LC solution using molecular dynamics and metadynamics simulations. The EDL expanded in the LC solution when a carbon surface (pristine graphene) lacked strong acid functional groups, producing a positive-rise potential at the electrode. In contrast, the EDL was compressed for an oxidized surface (graphene oxide), producing a negative-rise electrode potential. These results established the linkage between rise potentials and specific surface functional groups (strong acids) and demonstrated on a molecular scale changes in the EDL using oxidized or pristine carbons.

Effect of Strong Acid Functional Groups on Electrode Rise Potential in Capacitive Mixing by Double Layer Expansion

KAUST Repository

Hatzell, Marta C.; Raju, Muralikrishna; Watson, Valerie J.; Stack, Andrew G.; van Duin, Adri C. T.; Logan, Bruce E.

2014-01-01

© 2014 American Chemical Society. The amount of salinity-gradient energy that can be obtained through capacitive mixing based on double layer expansion depends on the extent the electric double layer (EDL) is altered in a low salt concentration (LC) electrolyte (e.g., river water). We show that the electrode-rise potential, which is a measure of the EDL perturbation process, was significantly (P = 10^-5) correlated to the concentration of strong acid surface functional groups using five types of activated carbon. Electrodes with the lowest concentration of strong acids (0.05 mmol g^-1) had a positive rise potential of 59 ± 4 mV in the LC solution, whereas the carbon with the highest concentration (0.36 mmol g^-1) had a negative rise potential (-31 ± 5 mV). Chemical oxidation of a carbon (YP50) using nitric acid decreased the electrode rise potential from 46 ± 2 mV (unaltered) to -6 ± 0.5 mV (oxidized), producing a whole cell potential (53 ± 1.7 mV) that was 4.4 times larger than that obtained with identical electrode materials (from 12 ± 1 mV). Changes in the EDL were linked to the behavior of specific ions in a LC solution using molecular dynamics and metadynamics simulations. The EDL expanded in the LC solution when a carbon surface (pristine graphene) lacked strong acid functional groups, producing a positive-rise potential at the electrode. In contrast, the EDL was compressed for an oxidized surface (graphene oxide), producing a negative-rise electrode potential. These results established the linkage between rise potentials and specific surface functional groups (strong acids) and demonstrated on a molecular scale changes in the EDL using oxidized or pristine carbons.

Beneficial effects of amino acid-functionalized graphene nanosheets incorporated in the photoanode material of dye-sensitized solar cells: A practical and theoretical study

International Nuclear Information System (INIS)

Taki, Mahmood; Rezaei, Behzad; Fani, Najmeh; Borandeh, Sedigheh; Abdolmaleki, Amir; Ensafi, Ali A.

2017-01-01

Highlights: • Electrochemical properties of GO was improved with incorporated amino acids. • Functionalized amino acids could act as a reducing agent for GO. • Aromatic amino acids-GO had improved photovoltaic properties over aliphatic ones. • Aromatic ring of tyrosine was aligned in parallel to the GO sheet. • A bang gap for GO was emerged with functionalizing with amino acids. - Abstract: In this research, covalently functionalized graphene oxide (GO) with some biocompatible amino acids were incorporated to the TiO_2 film and employed as the photoanodes of dye-sensitized solar cells (DSSCs). Electrochemical analysis of the amino acids-functionalized graphene oxide (AFGs) confirmed that the attached amino acids could be acted as a reducing agent of the GO. The photovoltaic performance of the assembled DSSCs under illumination of simulated AM 1.5 sunlight (100 mW cm"−"2) showed an enhancement of about 4.1 and 1.8 fold for the solar cell assembled with the tyrosine-functionalized GO in relation to the control solar cells constructed with GO-TiO_2 composite and blank TiO_2 film, respectively. These results were in accordance with electron life time and transport time resulted from the open circuit voltage decay (OCVD), electrochemical impedance spectroscopy (EIS) and intensity modulated photocurrent spectroscopy (IMPS) analysis. The density functional theory (DFT) calculations exhibited a proper spacial arrangement for the tyrosine-GO structure that could improve electron transfer between the adjucent GO sheets. Density of electronic states (DOS) exhibited a gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels for the simulated AFG structures. This effect could facilitate the light adsorption process in near-IR region.

Beneficial effects of amino acid-functionalized graphene nanosheets incorporated in the photoanode material of dye-sensitized solar cells: A practical and theoretical study

Energy Technology Data Exchange (ETDEWEB)

Taki, Mahmood [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Rezaei, Behzad, E-mail: rezaei@cc.iut.ac.ir [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Fani, Najmeh [Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Islamic Republic of Iran (Iran, Islamic Republic of); Borandeh, Sedigheh [Center for Nanotechnology in Drug Delivery, Shiraz University of Medical Science, Shiraz 71345, Islamic Republic of Iran (Iran, Islamic Republic of); Abdolmaleki, Amir; Ensafi, Ali A. [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of)

2017-05-01

Highlights: • Electrochemical properties of GO was improved with incorporated amino acids. • Functionalized amino acids could act as a reducing agent for GO. • Aromatic amino acids-GO had improved photovoltaic properties over aliphatic ones. • Aromatic ring of tyrosine was aligned in parallel to the GO sheet. • A bang gap for GO was emerged with functionalizing with amino acids. - Abstract: In this research, covalently functionalized graphene oxide (GO) with some biocompatible amino acids were incorporated to the TiO{sub 2} film and employed as the photoanodes of dye-sensitized solar cells (DSSCs). Electrochemical analysis of the amino acids-functionalized graphene oxide (AFGs) confirmed that the attached amino acids could be acted as a reducing agent of the GO. The photovoltaic performance of the assembled DSSCs under illumination of simulated AM 1.5 sunlight (100 mW cm{sup −2}) showed an enhancement of about 4.1 and 1.8 fold for the solar cell assembled with the tyrosine-functionalized GO in relation to the control solar cells constructed with GO-TiO{sub 2} composite and blank TiO{sub 2} film, respectively. These results were in accordance with electron life time and transport time resulted from the open circuit voltage decay (OCVD), electrochemical impedance spectroscopy (EIS) and intensity modulated photocurrent spectroscopy (IMPS) analysis. The density functional theory (DFT) calculations exhibited a proper spacial arrangement for the tyrosine-GO structure that could improve electron transfer between the adjucent GO sheets. Density of electronic states (DOS) exhibited a gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels for the simulated AFG structures. This effect could facilitate the light adsorption process in near-IR region.

Serum uric acid to creatinine ratio: A predictor of incident chronic kidney disease in type 2 diabetes mellitus patients with preserved kidney function.

Science.gov (United States)

Gu, Liubao; Huang, Liji; Wu, Haidi; Lou, Qinglin; Bian, Rongwen

2017-05-01

Serum uric acid has shown to be a predictor of renal disease progression in most but not all studies. This study aims to test whether renal function-normalized serum uric acid is superior to serum uric acid as the predictor of incident chronic kidney disease in type 2 diabetes mellitus patients. In this study, 1339 type 2 diabetes mellitus patients with estimated glomerular filtration rate ⩾60 mL/min/1.73 m 2 and normouricemia were included. Renal function-normalized serum uric acid was calculated using serum uric acid/creatinine. Cox regression analysis was used to estimate the association between serum uric acid, renal function-normalized serum uric acid and incident chronic kidney disease. In total, 74 (5.53%) patients developed to chronic kidney disease 3 or greater during a median follow-up of 4 years, with older ages, longer diabetes duration and lower estimated glomerular filtration rate at baseline. The decline rate of estimated glomerular filtration rate was positively correlated with serum uric acid/creatinine ( r = 0.219, p uric acid ( r = 0.005, p = 0.858). Moreover, multivariate analysis revealed that serum uric acid was not an independent risk factor for incident chronic kidney disease ( p = 0.055), whereas serum uric acid to creatinine ratio was significantly associated with incident chronic kidney disease independently of potential confounders including baseline estimated glomerular filtration rate. serum uric acid to creatinine ratio might be a better predictor of incident chronic kidney disease in type 2 diabetes mellitus patients.

Properties of poly(lactic acid)/hydroxyapatite composite through the use of epoxy functional compatibilizers for biomedical application.

Science.gov (United States)

Monmaturapoj, Naruporn; Srion, Autcharaporn; Chalermkarnon, Prasert; Buchatip, Suthawan; Petchsuk, Atitsa; Noppakunmongkolchai, Warobon; Mai-Ngam, Katanchalee

2017-08-01

A composite of 70/30 poly(lactic acid)/hydroxyapatite was systematically prepared using various amounts of glycidyl methacrylate as reactive compatibilizer or Joncryl ADR®-4368 containing nine glycidyl methacrylate functions as a chain extension/branching agent to improve the mechanical and biological properties for suitable usage as internal bone fixation devices. The effect of glycidyl methacrylate/Joncryl on mechanical properties of poly(lactic acid)/hydroxyapatite was investigated through flexural strength. Cell proliferation and differentiation of osteoblast-like MC3T3-E1 cells cultured on the composite samples were determined by Alamar Blue assay and alkaline phosphatase expression, respectively. Result shows that flexural strength tends to decrease, as glycidyl methacrylate content increases except for 1 wt.% glycidyl methacrylate. With an addition of dicumyl peroxide, the flexural strength shows an improvement than that of without dicumyl peroxide probably due to the chemical bonding of the hydroxyapatite and poly(lactic acid) as revealed by FTIR and NMR, whereas the composite with 5 wt.% Joncryl shows the best result, as the flexural strength increases getting close to pure poly(lactic acid). The significant morphology change could be seen in composite with Joncryl where the uniform agglomeration of hydroxyapatite particles oriented in poly(lactic acid) matrix. Addition of the epoxy functional compatibilizers at suitable percentages could also have benefits to cellular attachment, proliferation, differentiation and mineralization. So that, this poly(lactic acid)/hydroxyapatite composite could be a promising material to be used as internal bone fixation devices such as screws, pins and plates.

The effect of natural and synthetic fatty acids on membrane structure, microdomain organization, cellular functions and human health.

Science.gov (United States)

Ibarguren, Maitane; López, David J; Escribá, Pablo V

2014-06-01

This review deals with the effects of synthetic and natural fatty acids on the biophysical properties of membranes, and on their implication on cell function. Natural fatty acids are constituents of more complex lipids, like triacylglycerides or phospholipids, which are used by cells to store and obtain energy, as well as for structural purposes. Accordingly, natural and synthetic fatty acids may modify the structure of the lipid membrane, altering its microdomain organization and other physical properties, and provoking changes in cell signaling. Therefore, by modulating fatty acids it is possible to regulate the structure of the membrane, influencing the cell processes that are reliant on this structure and potentially reverting pathological cell dysfunctions that may provoke cancer, diabetes, hypertension, Alzheimer's and Parkinson's disease. The so-called Membrane Lipid Therapy offers a strategy to regulate the membrane composition through drug administration, potentially reverting pathological processes by re-adapting cell membrane structure. Certain fatty acids and their synthetic derivatives are described here that may potentially be used in such therapies, where the cell membrane itself can be considered as a target to combat disease. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

Amino acids and proteins

NARCIS (Netherlands)

van Goudoever, Johannes B.; Vlaardingerbroek, Hester; van den Akker, Chris H.; de Groof, Femke; van der Schoor, Sophie R. D.

2014-01-01

Amino acids and protein are key factors for growth. The neonatal period requires the highest intake in life to meet the demands. Those demands include amino acids for growth, but proteins and amino acids also function as signalling molecules and function as neurotransmitters. Often the nutritional

In Vitro Effect of Fatty Acids Identified in the Plasma of Obese Adolescents on the Function of Pancreatic ?-Cells

OpenAIRE

Velasquez, Claudia; Vasquez, Juan Sebastian; Balcazar, Norman

2017-01-01

Background The increase in circulating free fatty acid (FFA) levels is a major factor that induces malfunction in pancreatic ?-cells. We evaluated the effect of FFAs reconstituted according to the profile of circulating fatty acids found in obese adolescents on the viability and function of the murine insulinoma cell line (mouse insulinoma [MIN6]). Methods From fatty acids obtained commercially, plasma-FFA profiles of three different youth populations were reconstituted: obese with metabolic ...

High fat-diet and saturated fatty acid palmitate inhibits IGF-1 function in chondrocytes.

Science.gov (United States)

Nazli, S A; Loeser, R F; Chubinskaya, S; Willey, J S; Yammani, R R

2017-09-01

Insulin-like growth factor-1 (IGF-1) promotes matrix synthesis and cell survival in cartilage. Chondrocytes from aged and osteoarthritic cartilage have a reduced response to IGF-1. The purpose of this study was to determine the effect of free fatty acids (FFA) present in a high-fat diet on IGF-1 function in cartilage and the role of endoplasmic reticulum (ER) stress. C57BL/6 male mice were maintained on either a high-fat (60% kcal from fat) or a low-fat (10% kcal from fat) diet for 4 months. Mice were then sacrificed; femoral head cartilage caps were collected and treated with IGF-1 to measure proteoglycan (PG) synthesis. Cultured human chondrocytes were treated with 500 μM FFA palmitate or oleate, followed by stimulation with (100 ng/ml) IGF-1 overnight to measure CHOP (a protein marker for ER stress) and PG synthesis. Human chondrocytes were pre-treated with palmitate or 1 mM 4-phenyl butyric acid (PBA) or 1 μM C-Jun N terminal Kinase (JNK) inhibitor, and IGF-1 function (PG synthesis and signaling) was measured. Cartilage explants from mice on the high fat-diet showed reduced IGF-1 mediated PG synthesis compared to a low-fat group. Treatment of human chondrocytes with palmitate induced expression of CHOP, activated JNK and inhibited IGF-1 function. PBA, a small molecule chemical chaperone that alleviates ER stress rescued IGF-1 function and a JNK inhibitor rescued IGF-1 signaling. Palmitate-induced ER stress inhibited IGF-1 function in chondrocytes/cartilage via activating the mitogen-activated protein (MAP) kinase JNK. This is the first study to demonstrate that ER stress is metabolic factor that regulates IGF-1 function in chondrocytes. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Amine-modified hyaluronic acid-functionalized porous silicon nanoparticles for targeting breast cancer tumors

Science.gov (United States)

Almeida, Patrick V.; Shahbazi, Mohammad-Ali; Mäkilä, Ermei; Kaasalainen, Martti; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A.

2014-08-01

Active targeting of nanoparticles to receptor-overexpressing cancer cells has great potential for enhancing the cellular uptake of nanoparticles and for reducing fast clearance of the nanoparticles from the body. Herein, we present a preparation method of a porous silicon (PSi)-based nanodelivery system for breast cancer targeting, by covalently conjugating a synthesized amide-modified hyaluronic acid (HA+) derived polymer on the surface of undecylenic acid-modified thermally hydrocarbonized PSi (UnTHCPSi) nanoparticles. The resulting UnTHCPSi-HA+ nanoparticles showed relatively small size, reduced polydispersibility, high biocompatibility, improved colloidal and human plasma stability, as well as enhanced cellular interactions and internalization. Moreover, we demonstrated that the enhanced cellular association of UnTHCPSi-HA+ relies on the capability of the conjugated HA+ to bind and consequently target CD44 receptors expressed on the surface of breast cancer cells, thus making the HA+-functionalized UnTHCPSi nanoparticles a suitable and promising nanoplatform for the targeting of CD44-overexpressing breast tumors and for drug delivery.Active targeting of nanoparticles to receptor-overexpressing cancer cells has great potential for enhancing the cellular uptake of nanoparticles and for reducing fast clearance of the nanoparticles from the body. Herein, we present a preparation method of a porous silicon (PSi)-based nanodelivery system for breast cancer targeting, by covalently conjugating a synthesized amide-modified hyaluronic acid (HA+) derived polymer on the surface of undecylenic acid-modified thermally hydrocarbonized PSi (UnTHCPSi) nanoparticles. The resulting UnTHCPSi-HA+ nanoparticles showed relatively small size, reduced polydispersibility, high biocompatibility, improved colloidal and human plasma stability, as well as enhanced cellular interactions and internalization. Moreover, we demonstrated that the enhanced cellular association of Un

Identification of differences in human and great ape phytanic acid metabolism that could influence gene expression profiles and physiological functions

Directory of Open Access Journals (Sweden)

Siegmund Kimberly D

2010-10-01

Full Text Available Abstract Background It has been proposed that anatomical differences in human and great ape guts arose in response to species-specific diets and energy demands. To investigate functional genomic consequences of these differences, we compared their physiological levels of phytanic acid, a branched chain fatty acid that can be derived from the microbial degradation of chlorophyll in ruminant guts. Humans who accumulate large stores of phytanic acid commonly develop cerebellar ataxia, peripheral polyneuropathy, and retinitis pigmentosa in addition to other medical conditions. Furthermore, phytanic acid is an activator of the PPAR-alpha transcription factor that influences the expression of genes relevant to lipid metabolism. Results Despite their trace dietary phytanic acid intake, all great ape species had elevated red blood cell (RBC phytanic acid levels relative to humans on diverse diets. Unlike humans, chimpanzees showed sexual dimorphism in RBC phytanic acid levels, which were higher in males relative to females. Cultured skin fibroblasts from all species had a robust capacity to degrade phytanic acid. We provide indirect evidence that great apes, in contrast to humans, derive significant amounts of phytanic acid from the hindgut fermentation of plant materials. This would represent a novel reduction of metabolic activity in humans relative to the great apes. Conclusion We identified differences in the physiological levels of phytanic acid in humans and great apes and propose this is causally related to their gut anatomies and microbiomes. Phytanic acid levels could contribute to cross-species and sex-specific differences in human and great ape transcriptomes, especially those related to lipid metabolism. Based on the medical conditions caused by phytanic acid accumulation, we suggest that differences in phytanic acid metabolism could influence the functions of human and great ape nervous, cardiovascular, and skeletal systems.

The bile acids, deoxycholic acid and ursodeoxycholic acid, regulate colonic epithelial wound healing.

Science.gov (United States)

Mroz, Magdalena S; Lajczak, Natalia K; Goggins, Bridie J; Keely, Simon; Keely, Stephen J

2018-03-01

The intestinal epithelium constitutes an innate barrier which, upon injury, undergoes self-repair processes known as restitution. Although bile acids are known as important regulators of epithelial function in health and disease, their effects on wound healing processes are not yet clear. Here we set out to investigate the effects of the colonic bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on epithelial restitution. Wound healing in T 84 cell monolayers grown on transparent, permeable supports was assessed over 48 h with or without bile acids. Cell migration was measured in Boyden chambers. mRNA and protein expression were measured by RT-PCR and Western blotting. DCA (50-150 µM) significantly inhibited wound closure in cultured epithelial monolayers and attenuated cell migration in Boyden chamber assays. DCA also induced nuclear accumulation of the farnesoid X receptor (FXR), whereas an FXR agonist, GW4064 (10 µM), inhibited wound closure. Both DCA and GW4064 attenuated the expression of CFTR Cl - channels, whereas inhibition of CFTR activity with either CFTR- inh -172 (10 µM) or GlyH-101 (25 µM) also prevented wound healing. Promoter/reporter assays revealed that FXR-induced downregulation of CFTR is mediated at the transcriptional level. In contrast, UDCA (50-150 µM) enhanced wound healing in vitro and prevented the effects of DCA. Finally, DCA inhibited and UDCA promoted mucosal healing in an in vivo mouse model. In conclusion, these studies suggest bile acids are important regulators of epithelial wound healing and are therefore good targets for development of new drugs to modulate intestinal barrier function in disease treatment. NEW & NOTEWORTHY The secondary bile acid, deoxycholic acid, inhibits colonic epithelial wound healing, an effect which appears to be mediated by activation of the nuclear bile acid receptor, FXR, with subsequent downregulation of CFTR expression and activity. In contrast, ursodeoxycholic acid promotes

Biotransformation of Flavonoid Conjugates with Fatty Acids and Evaluations of Their Functionalities

Directory of Open Access Journals (Sweden)

Cynthia Q. Sun

2017-11-01

Full Text Available Enzymatic conjugation with fatty acids including omega-3 polyunsaturated fatty acids (ω-3 PUFAs derived from fish oil to three citrus fruit-derived flavonoids: grapefruit extract, naringin, and neohesperidin dihydrochalcone were investigated. The conversions were achieved over 85% under the catalysis of lipase Novozyme 435 in acetone at 45°C at semi-preparative scale. The conjugates were purified via solvent partition and silica gel chromatography and achieved 90–98% in purity. The NMR analysis of the conjugates confirmed that the fatty acid carbon chain was linked onto the primary –OH group on the glucose moiety of the flavonoids. The purified flavonoid conjugates alongside their original flavonoids were analyzed for antioxidant activities via 2,2-diphenyl-1-picrylhydrazyl scavenging assay, and anti-peroxidation test via peroxide values measured during a 1-week fish oil storage trial. Vascular endothelial growth factor (VEGF assay was conducted with 1, 10, and 100 μM of naringin and grapefruits and their conjugates, respectively, and total VEGF levels were measured at 24 and 48 h, respectively, using ELISA and dot blot analysis. The results from these functionality experiments demonstrated that flavonoid FA conjugates have at least comparable (if not higher antioxidant activity, anti-peroxidation activity, and anti-angiogenic activity.

Tranexamic acid increases early perioperative functional outcomes after total knee arthroplasty

Directory of Open Access Journals (Sweden)

Matthew J. Grosso, MD

2018-03-01

Full Text Available Background: The purpose of this study was to investigate the influence of tranexamic acid (TXA on functional outcomes in the immediate postoperative period after total knee arthroplasty (TKA. We hypothesized that the known benefits of TXA would confer measurable clinical improvements in physical therapy (PT performance, decrease pain, and decrease hospital length of stay (LOS. Methods: We retrospectively analyzed 560 TKA patients, including 280 consecutive patients whose surgery was performed before the initiation of a standardized TXA protocol and the first 280 patients who received TXA after protocol initiation. Outcome measurements included postoperative changes in hemoglobin and hematocrit, LOS, pain scores, destination of discharge, and steps ambulated with PT over 5 sessions. Results: TXA administration resulted in less overall drops in hemoglobin (P < .001 and hematocrit levels (P < .001. Moreover, patients administered TXA ambulated more than their counterparts during every PT session, which was statistically significant during the second (P = .010, third (P = .011, and fourth (P = .024 sessions. On average, the TXA cohort ambulated 20% more per PT session than patients who did not receive TXA (P < .001. TXA administration did not influence pain levels during PT, hospital LOS, or discharge destination in this investigation. Conclusions: It is well known that TXA reduces postoperative anemia, but this study also demonstrates that it confers early perioperative functional benefits for TKA patients. Potential mechanisms for this benefit include reduced rates of postoperative anemia and reduced rates of hemarthroses. Keywords: Tranexamic acid, Total knee arthroplasty, Blood loss, Physical therapy

The shikimate pathway: review of amino acid sequence, function and three-dimensional structures of the enzymes.

Science.gov (United States)

Mir, Rafia; Jallu, Shais; Singh, T P

2015-06-01

The aromatic compounds such as aromatic amino acids, vitamin K and ubiquinone are important prerequisites for the metabolism of an organism. All organisms can synthesize these aromatic metabolites through shikimate pathway, except for mammals which are dependent on their diet for these compounds. The pathway converts phosphoenolpyruvate and erythrose 4-phosphate to chorismate through seven enzymatically catalyzed steps and chorismate serves as a precursor for the synthesis of variety of aromatic compounds. These enzymes have shown to play a vital role for the viability of microorganisms and thus are suggested to present attractive molecular targets for the design of novel antimicrobial drugs. This review focuses on the seven enzymes of the shikimate pathway, highlighting their primary sequences, functions and three-dimensional structures. The understanding of their active site amino acid maps, functions and three-dimensional structures will provide a framework on which the rational design of antimicrobial drugs would be based. Comparing the full length amino acid sequences and the X-ray crystal structures of these enzymes from bacteria, fungi and plant sources would contribute in designing a specific drug and/or in developing broad-spectrum compounds with efficacy against a variety of pathogens.

Identification of a highly conserved valine-glycine-phenylalanine amino acid triplet required for HIV-1 Nef function

Directory of Open Access Journals (Sweden)

Meuwissen Pieter J

2012-04-01

Full Text Available Abstract Background The Nef protein of HIV facilitates virus replication and disease progression in infected patients. This role as pathogenesis factor depends on several genetically separable Nef functions that are mediated by interactions of highly conserved protein-protein interaction motifs with different host cell proteins. By studying the functionality of a series of nef alleles from clinical isolates, we identified a dysfunctional HIV group O Nef in which a highly conserved valine-glycine-phenylalanine (VGF region, which links a preceding acidic cluster with the following proline-rich motif into an amphipathic surface was deleted. In this study, we aimed to study the functional importance of this VGF region. Results The dysfunctional HIV group O8 nef allele was restored to the consensus sequence, and mutants of canonical (NL4.3, NA-7, SF2 and non-canonical (B2 and C1422 HIV-1 group M nef alleles were generated in which the amino acids of the VGF region were changed into alanines (VGF→AAA and tested for their capacity to interfere with surface receptor trafficking, signal transduction and enhancement of viral replication and infectivity. We found the VGF motif, and each individual amino acid of this motif, to be critical for downregulation of MHC-I and CXCR4. Moreover, Nef’s association with the cellular p21-activated kinase 2 (PAK2, the resulting deregulation of cofilin and inhibition of host cell actin remodeling, and targeting of Lck kinase to the trans-golgi-network (TGN were affected as well. Of particular interest, VGF integrity was essential for Nef-mediated enhancement of HIV virion infectivity and HIV replication in peripheral blood lymphocytes. For targeting of Lck kinase to the TGN and viral infectivity, especially the phenylalanine of the triplet was essential. At the molecular level, the VGF motif was required for the physical interaction of the adjacent proline-rich motif with Hck. Conclusion Based on these findings, we

Functional genomics for food microbiology: Molecular mechanisms of weak organic acid preservative adaptation in yeast

NARCIS (Netherlands)

Brul, S.; Kallemeijn, W.; Smits, G.

2008-01-01

The recent era of genomics has offered tremendous possibilities to biology. This concise review describes the possibilities of applying (functional) genomics studies to the field of microbial food stability. In doing so, the studies on weak-organic-acid stress response in yeast are discussed by way

Functionalization of yogurts with Agaricus bisporus extracts encapsulated in spray-dried maltodextrin crosslinked with citric acid.

Science.gov (United States)

Francisco, Cristhian R L; Heleno, Sandrina A; Fernandes, Isabel P M; Barreira, João C M; Calhelha, Ricardo C; Barros, Lillian; Gonçalves, Odinei Hess; Ferreira, Isabel C F R; Barreiro, Maria Filomena

2018-04-15

Mushroom extracts contain bioactive compounds potentially useful to functionalize foodstuffs. Herein, alcoholic extracts of Agaricus bisporus were studied for their bioactivity and viability as functional ingredients in a food product with high water content (yogurt). Extracts were microencapsulated (to improve their stability and hydrophilicity) by spray-drying, using maltodextrin crosslinked with citric acid as encapsulating material. The effect of thermal treatment (after atomization) on crosslinking and bioactivity of microspheres was tested. The incorporation of free and thermally untreated forms resulted in yogurts with higher initial antioxidant activity (EC 50 values: 214 and 272 mg.mL -1 ) that decreased after 7 days (EC 50 values: 248 and 314 mg.mL -1 ). Contrarily, thermally treated microencapsulated extracts showed higher antioxidant activity after the same period (EC 50 values, 0 days: 106 mg.mL -1 ; 7 days: 48.7 mg.mL -1 ), in result of an effective protection provided by microencapsulation with crosslinked maltodextrin and citric acid. Functionalized yogurts showed an overall maintenance of nutritional properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Novel sulfonated poly (ether ether ketone)/phosphonic acid-functionalized titania nanohybrid membrane by an in situ method for direct methanol fuel cells

Science.gov (United States)

Wu, Hong; Cao, Ying; Li, Zhen; He, Guangwei; Jiang, Zhongyi

2015-01-01

Sulfonated poly (ether ether ketone)/phosphonic acid-functionalized titania nanohybrid membranes are prepared by an in situ method using titanium tetrachloride (TiCl4) as inorganic precursor and amino trimethylene phosphonic acid (ATMP) as modifier. Phosphonic acid-functionalized titania nanoparticles with a uniform particle size of ∼50 nm are formed and dispersed homogeneously in the SPEEK matrix with good interfacial compatibility. Accordingly, the nanohybrid membranes display remarkably enhanced proton conduction property due to the incorporation of additional sites for proton transport and the formation of well-connected channels by bridging the hydrophilic domains in SPEEK matrix. The nanohybrid membrane with 6 wt. % of phosphonic acid-functionalized titania nanoparticles exhibits the highest proton conductivity of 0.334 S cm-1 at 65 °C and 100% RH, which is 63.7% higher than that of pristine SPEEK membrane. Furthermore, the as-prepared nanohybrid membranes also show elevated thermal and mechanical stabilities as well as decreased methanol permeability.

ALKALI RESISTANT CATALYST

DEFF Research Database (Denmark)

2008-01-01

The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

International Nuclear Information System (INIS)

Jiang, Tingshun; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

2014-01-01

Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH 3 -TPD and N 2 physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)–MCM-48 samples, SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO 4 2− /Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h −1 and the reaction temperature is 140 °C. - Highlights: • Sulfuric acid functional mesoporous solid acid catalysts were prepared via impregnation method. • The alkylation of phenol with tert-butyl alcohol was carried out over these solid acid catalysts. • The catalytic activity of SO 4 2− /Zr-MCM-48-25 catalyst is much higher than that of the others. • A maximum phenol conversion of 91.6% was achieved under optimum reaction conditions for SO 4 2− /Zr-MCM-48-25

Control of cell function on a phospholipid polymer having phenylboronic acid moiety

Energy Technology Data Exchange (ETDEWEB)

Saito, Aya; Ishihara, Kazuhiko [Department of Materials Engineering, School of Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Konno, Tomohiro [Center for NanoBio Integration, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ikake, Hiroki; Kurita, Kimio, E-mail: konno@bioeng.t.u-tokyo.ac.j [Department of Materials and Applied Chemistry, Graduate School of Science and Technology, Nihon University, 1-8-14, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan)

2010-10-01

We synthesized a water-insoluble phospholipid polymer bearing a phenylboronic acid moiety (PMBV), which induces cell adhesion through a specific interaction with the glycoprotein, fibronectin. Surface plasmon resonance analysis revealed that fibronectin was adsorbed on the PMBV surface. When fibroblasts were cultured on the PMBV surface, the cells adhered and proliferated normally while showing a spherical morphology. In addition, the adherent cells were able to detach after the addition of sugar molecules, which bound to phenylboronic acid through an exchange reaction. The cell cycle of adherent cells was evaluated with the embedded HeLa-Fucci cells by using a fluorescent ubiquitination-based cell cycle indicator. The cell-cycle analysis by fluorescence microscopy indicated that the adherent HeLa-Fucci cells tended to converge to the G1 phase. The differentiation of mesenchymal stem cells to chondrocytes was accelerated on PMBV in the presence of bone morphogenetic protein-2. We concluded that PMBV is a useful surface in experiments for assessing cellular function and differentiation.

Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

International Nuclear Information System (INIS)

Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia; Lu, Xiaoquan; Zhou, Xibin

2014-01-01

Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via π–π conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 μM, and 10–1000 μM, with the detection limits (S/N = 3) of 10.09 μM, 0.29 μM and 1.24 μM, respectively. Furthermore, the modified electrode was investigated for real sample analysis

Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

Energy Technology Data Exchange (ETDEWEB)

Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China); Lu, Xiaoquan, E-mail: Luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070 (China); Zhou, Xibin, E-mail: zhouxb@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China)

2014-05-01

Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via π–π conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 μM, and 10–1000 μM, with the detection limits (S/N = 3) of 10.09 μM, 0.29 μM and 1.24 μM, respectively. Furthermore, the modified electrode was investigated for real sample analysis.

Lactobacillus casei combats acid stress by maintaining cell membrane functionality.

Science.gov (United States)

Wu, Chongde; Zhang, Juan; Wang, Miao; Du, Guocheng; Chen, Jian

2012-07-01

Lactobacillus casei strains have traditionally been recognized as probiotics and frequently used as adjunct culture in fermented dairy products where lactic acid stress is a frequently encountered environmental condition. We have investigated the effect of lactic acid stress on the cell membrane of L. casei Zhang [wild type (WT)] and its acid-resistant mutant Lbz-2. Both strains were grown under glucose-limiting conditions in chemostats; following challenge by low pH, the cell membrane stress responses were investigated. In response to acid stress, cell membrane fluidity decreased and its fatty acid composition changed to reduce the damage caused by lactic acid. Compared with the WT, the acid-resistant mutant exhibited numerous survival advantages, such as higher membrane fluidity, higher proportions of unsaturated fatty acids, and higher mean chain length. In addition, cell integrity analysis showed that the mutant maintained a more intact cellular structure and lower membrane permeability after environmental acidification. These results indicate that alteration in membrane fluidity, fatty acid distribution, and cell integrity are common mechanisms utilized by L. casei to withstand severe acidification and to reduce the deleterious effect of lactic acid on the cell membrane. This detailed comparison of cell membrane responses between the WT and mutant add to our knowledge of the acid stress adaptation and thus enable new strategies to be developed aimed at improving the industrial performance of this species under acid stress.

Effect of omega-3 fatty acids supplementation during pregnancy on lung function in preschoolers: a clinical trial.

Science.gov (United States)

Gutiérrez-Delgado, R I; Barraza-Villarreal, A; Escamilla-Núñez, C; Hernández-Cadena, L; Garcia-Feregrino, R; Shackleton, C; Ramakrishnan, U; Sly, P D; Romieu, I

2018-04-04

Prenatal omega-3 fatty acids improve alveolarization, diminish inflammation, and improve pulmonary growth, but it is unclear whether these outcomes translate into improved postnatal lung function. We assessed the effect of prenatal supplementation with docosahexaenoic acid (DHA) on offspring lung function through 60 months of age. We included a cohort of 772 Mexican preschoolers whose mothers participated in a clinical trial (NCT00646360) of supplementation with DHA or a placebo from week 18-22 of gestation through delivery. The children were followed after birth and anthropometric measurements and forced oscillation tests were performed at 36, 48, and 60 months of age. The effect of DHA was tested using a longitudinal mixed effect models. Overall, mean (Standard Deviation) of the measurements of respiratory system resistance and respiratory system reactance at 6, 8, and 10 Hz during follow up period were 11.3 (2.4), 11.1 (2.4), 10.3 (2.2) and -5.2 (1.6), -4.8 (1.7), -4.6 (1.6), respectively. There were no significant differences in pulmonary function by treatment group. DHA did not affect the average lung function or the trajectories through 60 months. Prenatal DHA supplementation did not influence pulmonary function in this cohort of Mexican preschoolers.

Synthesis and characterization of triflic acid-functionalized mesoporous Zr-TMS catalysts: heterogenization of CF3SO3H over Zr-TMS and its catalytic activity

NARCIS (Netherlands)

Chidambaram, M.; Curulla Ferre, D.; Singh, A.P.; Anderson, B.G.

2003-01-01

Triflic acid-functionalized Zr-TMS (zirconium oxide with a mesostructured framework; TMS, transition metal oxide mesoporous molecular sieves) catalysts have been synthesized by functionalizing triflic acid onto the walls of Zr-TMS via post synthesis method. The synthesized materials were

Molecular interaction of pinic acid with sulfuric acid

DEFF Research Database (Denmark)

Elm, Jonas; Kurtén, Theo; Bilde, Merete

2014-01-01

We investigate the molecular interactions between the semivolatile α-pinene oxidation product pinic acid and sulfuric acid using computational methods. The stepwise Gibbs free energies of formation have been calculated utilizing the M06-2X functional, and the stability of the clusters is evaluated...... cluster. The involvement of more than one pinic acid molecule in a single cluster is observed to lead to the formation of favorable (pinic acid)2(H2SO4) and (pinic acid)2(H2SO4)2 clusters. The identified most favorable growth paths starting from a single pinic acid molecule lead to closed structures...

Influence of acid diffusion on the performance of lead-acid cells

Energy Technology Data Exchange (ETDEWEB)

Kappus, W.; Bohmann, J.

1983-11-01

A model for the discharge performance of the lead-acid cell is proposed. Diffusion of acid into the porous electrodes, which is connected with diffusional polarization, is considered as the principal factor in the transport process. The end of discharge is determined either by acid depletion inside the electrodes or by exhaustion of the active material, where utilization of the active material as a function of the acid density and the specific current is determined from empirical expressions. Curves of diffusional polarizations as a function of the discharge time are presented. Calculated discharge capacities show the influence of various parameters such as electrode thickness, current, and acid density. Tubular and pasted plates are considered.

A Δ-9 Fatty Acid Desaturase Gene in the Microalga Myrmecia incisa Reisigl: Cloning and Functional Analysis

Directory of Open Access Journals (Sweden)

Wen-Bin Xue

2016-07-01

Full Text Available The green alga Myrmecia incisa is one of the richest natural sources of arachidonic acid (ArA. To better understand the regulation of ArA biosynthesis in M. incisa, a novel gene putatively encoding the Δ9 fatty acid desaturase (FAD was cloned and characterized for the first time. Rapid-amplification of cDNA ends (RACE was employed to yield a full length cDNA designated as MiΔ9FAD, which is 2442 bp long in sequence. Comparing cDNA open reading frame (ORF sequence to genomic sequence indicated that there are 8 introns interrupting the coding region. The deduced MiΔ9FAD protein is composed of 432 amino acids. It is soluble and localized in the chloroplast, as evidenced by the absence of transmembrane domains as well as the presence of a 61-amino acid chloroplast transit peptide. Multiple sequence alignment of amino acids revealed two conserved histidine-rich motifs, typical for Δ9 acyl-acyl carrier protein (ACP desaturases. To determine the function of MiΔ9FAD, the gene was heterologously expressed in a Saccharomyces cerevisiae mutant strain with impaired desaturase activity. Results of GC-MS analysis indicated that MiΔ9FAD was able to restore the synthesis of monounsaturated fatty acids, generating palmitoleic acid and oleic acid through the addition of a double bond in the Δ9 position of palmitic acid and stearic acid, respectively.

Acid-base equilibria inside amine-functionalized mesoporous silica.

Science.gov (United States)

Yamaguchi, Akira; Namekawa, Manato; Kamijo, Toshio; Itoh, Tetsuji; Teramae, Norio

2011-04-15

Acid-base equilibria and effective proton concentration inside a silica mesopore modified with a trimethyl ammonium (TMAP) layer were studied by steady-state fluorescence experiments. The mesoporous silica with a dense TMAP layer (1.4 molecules/nm(2)) was prepared by a post grafting of N-trimethoxysilylpropyl-N,N,N-trimethylammonium at surfactant-templated mesoporous silica (diameter of silica framework =3.1 nm). The resulting TMAP-modified mesoporous silica strongly adsorbed of anionic fluorescence indicator dyes (8-hydroxypyrene-1,3,6-trisulfonate (pyranine), 8-aminopyrene-1,3,6-trisulfonate (APTS), 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid disulfuric acid (TPPS), 2-naphthol-3,6-disulfonate (2NT)) and fluorescence excitation spectra of these dyes within TMAP-modified mesoporous silica were measured by varying the solution pH. The fluorescence experiments revealed that the acid-base equilibrium reactions of all pH indicator dyes within the TMAP-modified silica mesopore were quite different from those in bulk water. From the analysis of the acid-base equilibrium of pyranine, the following relationships between solution pH (pH(bulk)) and the effective proton concentration inside the pore (pH(pore)) were obtained: (1) shift of pH(pore) was 1.8 (ΔpH(pore)=1.8) for the pH(bulk) change from 2.1 to 9.1 (ΔpH(bulk)=7.0); (2) pH(pore) was not simply proportional to pH(bulk); (3) the inside of the TMAP-modified silica mesopore was suggested to be in a weak acidic or neutral condition when pH(bulk) was changed from 2.0 to 9.1. Since these relationships between pH(bulk) and pH(pore) could explain the acid-base equilibria of other pH indicator dyes (APTS, TPPS, 2NT), these relationships were inferred to describe the effective proton concentration inside the TMAP-modified silica mesopore. © 2011 American Chemical Society

Monoselective o-C–H Functionalizations of Mandelic Acid and α-Phenylglycine

Science.gov (United States)

2015-01-01

Pd-catalyzed C–H functionalization of mandelic acid and α-phenylglycine is reported. We have developed different protocols for the arylation, iodination, acetoxylation, and olefination of these substrates based on two different (Pd(II)/Pd(IV) and Pd(II)/Pd(0)) catalytic cycles. Four crucial features of these protocols are advantageous for practical applications. First, the α-hydroxyl and amino groups are protected with simple protecting groups such as acetates (Ac, Piv) and carbamates (Boc, Fmoc), respectively. Second, these protocols do not involve installation and removal of a directing group. Third, monoselectivity is accomplished. Fourth, no epimerization occurs at the vulnerable α-chiral centers. PMID:26162456

Recent progress in synthesis and surface functionalization of mesoporous acidic heterogeneous catalysts for esterification of free fatty acid feedstocks: A review

International Nuclear Information System (INIS)

Soltani, Soroush; Rashid, Umer; Al-Resayes, Saud Ibrahim; Nehdi, Imededdine Arbi

2017-01-01

Highlights: • Mesoporous catalysts have potential to esterify the wastes feedstocks. • Surface area of mesoporous catalysts depends on materials synthesis methods. • Hydrophobic surface of sulfonated catalyst causes adsorption on FFA particles. • Mesoporous catalysts have large active sites to trap free fatty acids particles. • Recyclability of mesoporous catalyst is a key feature for biodiesel production. - Abstract: Biodiesel is considered as a sulfur free, non-toxic and biodegradable source of energy and its burning provide less pollution than petroleum based fuels. In case of using fried waste oils, animal’s fats and waste cultivated oil which contain high free fatty acid (FFA), esterification is taking place. Through esterification reaction, catalyst is an integral part which accelerates the FFA conversion to the methyl ester (ME) in shorter reaction time. Although, most of the current catalysts have some defect such as poor recyclability, less surface area and poor porosity. Mesoporous materials have been recently attracted remarkable interests because of its desirable properties, such as large and harmonized surface area, tuneable mesoporous channels with flexible pore size, excellent thermal stability, and post-functionalization surface characteristics. The combination of remarkable physico-chemical and textural properties as well as high activity has proposed them as advanced materials. In this review, it has been attempted to present the details of fundamental properties of mesoporous catalysts, various synthetic methods and formation mechanisms, and surface functionalization methodologies. The effects of various factors (such as surface area, porosity, acidity, post-calcination temperature, and reaction parameters) on esterification of different feedstocks are discussed in detail. Furthermore, the kinetic study of esterification reaction in the presence of mesoporous catalysts is also elaborated. At the end, remarkable challenges and outlooks

Influence of humic acids on the migration behavior of radioactive and non-radioactive substances under conditions close to nature. Synthesis, radiometric determination of functional groups, complexation

International Nuclear Information System (INIS)

Pompe, S.; Bubner, M.; Schmeide, K.; Heise, K.H.; Bernhard, G.; Nitsche, H.

2000-04-01

The interaction behavior of humic acids with uranium(VI) and the influence of humic substances on the migration behavior of uranium was investigated. A main focus of this work was the synthesis of four different humic acid model substances and their characterization and comparison to the natural humic acid from Aldrich. A radiometric method for the determination of humic acid functional groups was applied in addition to conventional methods for the determination of the functionality of humic acids. The humic acid model substances show functional and structural properties comparable to natural humic acids. Modified humic acids with blocked phenolic OH were synthesized to determine the influence of phenolic OH groups on the complexation behavior of humic acids. A synthesis method for 14 C-labeled humic acids with high specific activity was developed. The complexation behavior of synthetic and natural humic acids with uranium(VI) was investigated by X-ray absorption spectroscopy, laser-induced fluorescence spectroscopy and FTIR spectroscopy. The synthetic model substances show an interaction behavior with uranium(VI) that is comparable to natural humic acids. This points to the fact that the synthetic humic acids simulate the functionality of their natural analogues very well. For the first time the influence of phenolic OH groups on the complexation behavior of humic acids was investigated by applying a modified humic acid with blocked phenolic OH groups. The formation of a uranyl hydroxy humate complex was identified by laserspectroscopic investigations of the complexation of Aldrich humic acid with uranium(VI) at pH7. The migration behavior of uranium in a sandy aquifer system rich in humic substances was investigated in column experiments. A part of uranium migrates non-retarded through the sediment, bound to humic colloids. The uranium migration behavior is strongly influenced by the kinetically controlled interaction processes of uranium with the humic colloids

[THE EFFECT OF ACID RAIN ON ULTRASTRUCTURE AND FUNCTIONAL PARAMETERS OF PHOTOSYNTHETIC APPARATUS OF PEA LEAVES].

Science.gov (United States)

Polishchuk, A V; Vodka, M V; Belyavskaya, N A; Khomochkin, A P; Zolotareva, E K

2016-01-01

The effects of simulated acid rain (SAR) on the ultrastructure and functional parameters of the photosynthetic apparatus were studied using 14-day-old pea leaves as test system. Pea plants were sprayed with an aqueous solution containing NaNO₃(0.2 mM) and Na₂SO₄(0.2 mM) (pH 5.6, a control variant), or with the same solution, which was acidified to pH 2.5 (acid variant). Functional characteristics were determined by chlorophyll fluorescence analysis. Acid rain application caused reduction in the efficiency of the photosynthetic electron transport by 25%, which was accompanied by an increase by 85% in the quantum yield of thermal dissipation of excess light quanta. Ultrastructural changes in chloroplast were registered by transmission electron microscopy (TEM) after two days of the SAR-treatment of pea leaves. In this case, the changes in the structure of grana, heterogeneity of thylakoids packaging in granum, namely, the increase of intra-thylakoid gaps and thickness of granal thylakoids compared to the control were found. The migration of protein complexes in thylakoid membranes of chloroplasts isolated from leaves treated with SAR was suppressed. It was shown also that carbonic anhydrase activity was inhibited in chloroplast preparations isolated from SAR-treated pea leaves. We proposed a hypothesis on the possible inactivation of thylakoid carbonic anhydrase under SAR and its involvement in the inhibition of photochemical activity of chloroplasts. The data obtained allows to suggest that acid rains negatively affect the photosynthetic apparatus disrupting the membrane system of chloroplast.

Association of Lead Exposure, Serum Uric Acid and Parameters of Renal Function in Nigerian Lead-Exposed Workers

Directory of Open Access Journals (Sweden)

DD Alasia

2010-09-01

Full Text Available Background: The presence of hyperuricemia and renal function impairment, especially in the absence of urate stone formation is strongly suggestive of lead nephropathy. The evaluation of this association is essential in areas where lead exposure is still prevalent and uncontrolled. Objective: To determine the relationship between serum uric acid and renal function indices in lead-exposed workers. Methods: A cross-sectional study of 190 adults with occupational lead exposure and 80 adults (comparison group, matched for age and sex was performed in Port Harcourt, South-south Nigeria. Blood lead was used as the biomarker of lead exposure while serum urea, serum creatinine, urine albumin (using urine albumin:creatinine ratio, estimated glomerular filtration rate (GFR and serum uric acid were the renal function indices measured. Results: Occupationally lead-exposed subjects had a significantly (p = 0.008 higher mean±SD blood lead levels (50.37±24.58 μg/dL than the comparison group (41.40±26.85. The mean±SD serum urea (8.6±2.3 mg/dL, creatinine (1.0±0.2 mg/dL and serum uric acid (4.6±1.2 mg/dL were significantly (p < 0.01 higher in the study subjects than the comparison group (7.6±2.4, 0.9±0.2, and 3.9±1.1 mg/dL, respectively. The mean±SD creatinine clearance was significantly (p = 0.002 lower in the study subjects than the comparison group (98.9±21.3 vs. 108.2±25.2 mL/min/1.72 m2. Serum uric acid level correlated positively with serum creatinine (r = 0.134 and negatively with GFR (r = ‑0.151. Conclusion: People with occupational lead exposure are at risk of developing hyperuricemia and renal impairment.

Assessment of central dopaminergic function using plasma-free homovanillic acid after debrisoquin administration.

Science.gov (United States)

Riddle, M A; Leckman, J F; Cohen, D J; Anderson, M; Ort, S I; Caruso, K A; Shaywitz, B A

1986-01-01

Central dopaminergic (DA) function in children and adults was assessed by monitoring plasma-free levels of the dopamine metabolite homovanillic acid (pHVA) before and after a single oral dose and chronic oral administration of debrisoquin. Debrisoquin inhibits peripheral metabolism of dopamine to HVA and does not cross the blood-brain barrier. By reducing peripheral formation of HVA through the use of debrisoquin, the remaining HVA in plasma more accurately reflects central DA activity. Debrisoquin administration resulted in marked reductions of pHVA in each of 12 patients studied. Eleven of the 12 subjects tolerated debrisoquin without physical or behavioral side effects. The debrisoquin administration method appears to be a safe and potentially valid technique for evaluating aspects of central dopaminergic function in children and adults.

Functional Properties of Plasticized Bio-Based Poly(Lactic Acid)_Poly(Hydroxybutyrate) (PLA_PHB) Films for Active Food Packaging

OpenAIRE

Burgos, Nuria; Armentano, Ilaria; Fortunati, Elena; Dominici, Franco; Luzi, Francesca; Fiori, Stefano; Cristofaro, Francesco; Visai, Livia; Jiménez, Alfonso; Kenny, José María

2017-01-01

Fully bio-based and biodegradable active films based on poly(lactic acid) (PLA) blended with poly(3-hydroxybutyrate) (PHB) and incorporating lactic acid oligomers (OLA) as plasticizers and carvacrol as active agent were extruded and fully characterized in their functional properties for antimicrobial active packaging. PLA_PHB films showed good barrier to water vapor, while the resistance to oxygen diffusion decreased with the addition of OLA and carvacrol. Their overall migration in aqueous f...

Helminthosporic acid functions as an agonist for gibberellin receptor.

Science.gov (United States)

Miyazaki, Sho; Jiang, Kai; Kobayashi, Masatomo; Asami, Tadao; Nakajima, Masatoshi

2017-11-01

Helminthosporol was isolated from a fungus, Helminthosporium sativum, as a natural plant growth regulator in 1963. It showed gibberellin-like bioactivity that stimulated the growth of the second leaf sheath of rice. After studying the structure-activity relationship between the compound and some synthesized analogs, it was found that helminthosporic acid (H-acid) has higher gibberellin-like activity and chemical stability than helminthosporol. In this study, we showed that (1) H-acid displays gibberellin-like activities not only in rice but also in Arabidopsis, (2) it regulates the expression of gibberellin-related genes, (3) it induces DELLA degradation through binding with a gibberellin receptor (GID1), and (4) it forms the GID1-(H-acid)-DELLA complex to transduce the gibberellin signal in the same manner as gibberellin. This work shows that the H-acid mode of action acts as an agonist for gibberellin receptor.

Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

Energy Technology Data Exchange (ETDEWEB)

Jiang, Tingshun, E-mail: tshjiang@mail.ujs.edu.cn; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

2014-10-15

Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH{sub 3}-TPD and N{sub 2} physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)–MCM-48 samples, SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO{sub 4}{sup 2−}/Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h{sup −1} and the reaction temperature is 140 °C. - Highlights: • Sulfuric acid functional mesoporous solid acid catalysts were prepared via impregnation method. • The alkylation of phenol with tert-butyl alcohol was carried out over these solid acid catalysts. • The catalytic activity of SO{sub 4}{sup 2−}/Zr-MCM-48-25 catalyst is much higher than that of the others. • A maximum phenol conversion of 91.6% was achieved under optimum reaction conditions for SO{sub 4}{sup 2−}/Zr-MCM-48-25.

B vitamins and n-3 fatty acids for brain development and function: review of human studies

NARCIS (Netherlands)

Rest, van de O.; Hooijdonk, L.W.A.; Doets, E.L.; Schiepers, O.J.G.; Eilander, J.H.C.; Groot, de C.P.G.M.

2012-01-01

Background: Nutrition is one of many factors that affect brain development and functioning, and in recent years the role of certain nutrients has been investigated. B vitamins and n–3 polyunsaturated fatty acids (PUFA) are two of the most promising and widely studied nutritional factors. Methods: In

Glutamate dehydrogenase (RocG) in Bacillus licheniformis WX-02: Enzymatic properties and specific functions in glutamic acid synthesis for poly-γ-glutamic acid production.

Science.gov (United States)

Tian, Guangming; Wang, Qin; Wei, Xuetuan; Ma, Xin; Chen, Shouwen

2017-04-01

Poly-γ-glutamic acid (γ-PGA), a natural biopolymer, is widely used in cosmetics, medicine, food, water treatment, and agriculture owing to its features of moisture sequestration, cation chelation, non-toxicity and biodegradability. Intracellular glutamic acid, the substrate of γ-PGA, is a limiting factor for high yield in γ-PGA production. Bacillus subtilis and Bacillus licheniformis are both important γ-PGA producing strains, and B. subtilis synthesizes glutamic acid in vivo using the unique GOGAT/GS pathway. However, little is known about the glutamate synthesis pathway in B. licheniformis. The aim of this work was to characterize the glutamate dehydrogenase (RocG) in glutamic acid synthesis from B. licheniformis with both in vivo and in vitro experiments. By re-directing the carbon flux distribution, the rocG gene deletion mutant WX-02ΔrocG produced intracellular glutamic acid with a concentration of 90ng/log(CFU), which was only 23.7% that of the wild-type WX-02 (380ng/log(CFU)). Furthermore, the γ-PGA yield of mutant WX-02ΔrocG was 5.37g/L, a decrease of 45.3% compared to the wild type (9.82g/L). In vitro enzymatic assays of RocG showed that RocG has higher affinity for 2-oxoglutarate than glutamate, and the glutamate synthesis rate was far above degradation. This is probably the first study to reveal the glutamic acid synthesis pathway and the specific functions of RocG in B. licheniformis. The results indicate that γ-PGA production can be enhanced through improving intracellular glutamic acid synthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Compositional and functional features of humic acid-like fractions from vermicomposting of sewage sludge and cow dung

Energy Technology Data Exchange (ETDEWEB)

Li Xiaowei [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Xing Meiyan, E-mail: xmy5000@163.com [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Yang Jian; Huang Zhidong [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

2011-01-30

The chemical changes occurring in five different substrates of sewage sludge spiked with different proportions of cow dung after vermicomposting with Eisenia foetida for 90 days were investigated. Their humic acid-like (HAL) fractions were isolated to determine the elemental and functional composition, and structural and functional characteristics using ultraviolet/visible, Fourier transform infrared (FT-IR) and fluorescence spectroscopies and scanning electron microscopy. After vermicomposting, the total organic C and C/N ratio decreased, and the total extractable C and humic acid (HA) C increased in all substrates. In the HAL fractions, the C and H contents, C/N and C/O and aliphatic structures, proteinaceous components and carbohydrates decreased, while the O and N and acidic functional group contents and C/H ratio, aromaticity and polycondensation structures increased. Further, the results suggest that the addition of cow dung to sewage sludge could improve the quality of organic matter humification of the substrates. The structures of HAL fractions in vermicomposts resembled those typical of soil HA, especially the vermicompost of cow dung alone. Scanning electron microscopy showed the microstructure of HAL fraction in final product became close-grained and lumpy. Overall results indicate that vermicomposting was an efficient technology for promoting organic matter (OM) humification in sewage sludge and cow dung alone, as well as in mixtures of both materials, improving their quality and environmental safety as a soil OM resource for utilization as soil amendments.

Compositional and functional features of humic acid-like fractions from vermicomposting of sewage sludge and cow dung.

Science.gov (United States)

Li, Xiaowei; Xing, Meiyan; Yang, Jian; Huang, Zhidong

2011-01-30

The chemical changes occurring in five different substrates of sewage sludge spiked with different proportions of cow dung after vermicomposting with Eisenia foetida for 90 days were investigated. Their humic acid-like (HAL) fractions were isolated to determine the elemental and functional composition, and structural and functional characteristics using ultraviolet/visible, Fourier transform infrared (FT-IR) and fluorescence spectroscopies and scanning electron microscopy. After vermicomposting, the total organic C and C/N ratio decreased, and the total extractable C and humic acid (HA) C increased in all substrates. In the HAL fractions, the C and H contents, C/N and C/O and aliphatic structures, proteinaceous components and carbohydrates decreased, while the O and N and acidic functional group contents and C/H ratio, aromaticity and polycondensation structures increased. Further, the results suggest that the addition of cow dung to sewage sludge could improve the quality of organic matter humification of the substrates. The structures of HAL fractions in vermicomposts resembled those typical of soil HA, especially the vermicompost of cow dung alone. Scanning electron microscopy showed the microstructure of HAL fraction in final product became close-grained and lumpy. Overall results indicate that vermicomposting was an efficient technology for promoting organic matter (OM) humification in sewage sludge and cow dung alone, as well as in mixtures of both materials, improving their quality and environmental safety as a soil OM resource for utilization as soil amendments. Copyright © 2010 Elsevier B.V. All rights reserved.

Compositional and functional features of humic acid-like fractions from vermicomposting of sewage sludge and cow dung

International Nuclear Information System (INIS)

Li Xiaowei; Xing Meiyan; Yang Jian; Huang Zhidong

2011-01-01

The chemical changes occurring in five different substrates of sewage sludge spiked with different proportions of cow dung after vermicomposting with Eisenia foetida for 90 days were investigated. Their humic acid-like (HAL) fractions were isolated to determine the elemental and functional composition, and structural and functional characteristics using ultraviolet/visible, Fourier transform infrared (FT-IR) and fluorescence spectroscopies and scanning electron microscopy. After vermicomposting, the total organic C and C/N ratio decreased, and the total extractable C and humic acid (HA) C increased in all substrates. In the HAL fractions, the C and H contents, C/N and C/O and aliphatic structures, proteinaceous components and carbohydrates decreased, while the O and N and acidic functional group contents and C/H ratio, aromaticity and polycondensation structures increased. Further, the results suggest that the addition of cow dung to sewage sludge could improve the quality of organic matter humification of the substrates. The structures of HAL fractions in vermicomposts resembled those typical of soil HA, especially the vermicompost of cow dung alone. Scanning electron microscopy showed the microstructure of HAL fraction in final product became close-grained and lumpy. Overall results indicate that vermicomposting was an efficient technology for promoting organic matter (OM) humification in sewage sludge and cow dung alone, as well as in mixtures of both materials, improving their quality and environmental safety as a soil OM resource for utilization as soil amendments.

Biological functions of iduronic acid in chondroitin/dermatan sulfate

OpenAIRE

Thelin, Martin A; Bartolini, Barbara; Axelsson, Jakob; Gustafsson, Renata; Tykesson, Emil; Pera, Edgar; Oldberg, ?ke; Maccarana, Marco; Malmstrom, Anders

2013-01-01

The presence of iduronic acid in chondroitin/dermatan sulfate changes the properties of the polysaccharides because it generates a more flexible chain with increased binding potentials. Iduronic acid in chondroitin/dermatan sulfate influences multiple cellular properties, such as migration, proliferation, differentiation, angiogenesis and the regulation of cytokine/growth factor activities. Under pathological conditions such as wound healing, inflammation and cancer, iduronic acid has diverse...

Synthesis of highly phosphonic acid functionalized benzene-bridged periodic mesoporous organosilicas for use as efficient dye adsorbents

International Nuclear Information System (INIS)

Deka, Juti Rani; Liu, Chia-Ling; Wang, Tzu-Hua; Chang, Wei-Chieh; Kao, Hsien-Ming

2014-01-01

Highlights: • Synthesis of highly phosphonic acid functionalized benzene-bridged PMOs. • Phosphonic acid loaded PMOs as adsorbent for cationic and anionic dyes. • Due to electrostatic interaction the adsorbent has high dye adsorption capacity. • π–π stacking interaction between benzene and dye enhances adsorption capacity. • Intraparticle diffusion played a dominant role in the adsorption process. - Abstract: Periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall were functionalized with a tunable content of phosphonic acid groups. These bifunctional materials were synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic conditions using nonionic surfactant Brij-S10 as template. The materials exhibited well-ordered mesostructures and were characterized by X-ray diffraction, nitrogen sorption, TEM, TGA, FTIR, and solid-state NMR measurements. The materials thus obtained were employed as adsorbents to remove different types of dyes, for example, cationic dyes methylene blue and phenosafranine, anionic orange II, and amphoteric rhodamine B, from aqueous solutions. The materials exhibited a remarkably high adsorption capacity than activated carbon due to their ordered mesostructures, a large number of phosphonic acid groups, and high surface areas. The adsorption was mainly governed by electrostatic interaction, but also involved π–π stacking interaction as well as hydrogen bonding. The adsorption kinetics can be better fitted by the pseudo-second order model. The adsorption process was controlled by the mechanisms of external mass transfer and intraparticle diffusion. The materials retained more than 97% dye removal efficiency after use for five consecutive cycles

Docosahexaenoic Acid-Derived Fatty Acid Esters of Hydroxy Fatty Acids (FAHFAs) With Anti-inflammatory Properties.

Science.gov (United States)

Kuda, Ondrej; Brezinova, Marie; Rombaldova, Martina; Slavikova, Barbora; Posta, Martin; Beier, Petr; Janovska, Petra; Veleba, Jiri; Kopecky, Jan; Kudova, Eva; Pelikanova, Terezie; Kopecky, Jan

2016-09-01

White adipose tissue (WAT) is a complex organ with both metabolic and endocrine functions. Dysregulation of all of these functions of WAT, together with low-grade inflammation of the tissue in obese individuals, contributes to the development of insulin resistance and type 2 diabetes. n-3 polyunsaturated fatty acids (PUFAs) of marine origin play an important role in the resolution of inflammation and exert beneficial metabolic effects. Using experiments in mice and overweight/obese patients with type 2 diabetes, we elucidated the structures of novel members of fatty acid esters of hydroxy fatty acids-lipokines derived from docosahexaenoic acid (DHA) and linoleic acid, which were present in serum and WAT after n-3 PUFA supplementation. These compounds contained DHA esterified to 9- and 13-hydroxyoctadecadienoic acid (HLA) or 14-hydroxydocosahexaenoic acid (HDHA), termed 9-DHAHLA, 13-DHAHLA, and 14-DHAHDHA, and were synthesized by adipocytes at concentrations comparable to those of protectins and resolvins derived from DHA in WAT. 13-DHAHLA exerted anti-inflammatory and proresolving properties while reducing macrophage activation by lipopolysaccharides and enhancing the phagocytosis of zymosan particles. Our results document the existence of novel lipid mediators, which are involved in the beneficial anti-inflammatory effects attributed to n-3 PUFAs, in both mice and humans. © 2016 by the American Diabetes Association.

Molecular Cloning and Functional Expression of a Δ9- Fatty Acid Desaturase from an Antarctic Pseudomonas sp. A3

Science.gov (United States)

Garba, Lawal; Mohamad Ali, Mohd Shukuri; Oslan, Siti Nurbaya; Rahman, Raja Noor Zaliha Raja Abd

2016-01-01

Fatty acid desaturase enzymes play an essential role in the synthesis of unsaturated fatty acids. Pseudomonas sp. A3 was found to produce a large amount of palmitoleic and oleic acids after incubation at low temperatures. Using polymerase Chain Reaction (PCR), a novel Δ9- fatty acid desaturase gene was isolated, cloned, and successfully expressed in Escherichia coli. The gene was designated as PA3FAD9 and has an open reading frame of 1,185 bp which codes for 394 amino acids with a predicted molecular weight of 45 kDa. The activity of the gene product was confirmed via GCMS, which showed a functional putative Δ9-fatty acid desaturase capable of increasing the total amount of cellular unsaturated fatty acids of the E. coli cells expressing the gene. The results demonstrate that the cellular palmitoleic acids have increased two-fold upon expression at 15°C using only 0.1 mM IPTG. Therefore, PA3FAD9 from Pseudomonas sp.A3 codes for a Δ9-fatty acid desaturase-like protein which was actively expressed in E. coli. PMID:27494717

Use of Calcium and Alendronic Acid Preparations in Correction of Structural and Functional Disorders of Bone Tissue in Thyrotoxicosis

Directory of Open Access Journals (Sweden)

O.B. Oliynyk

2012-02-01

Full Text Available Impact of calcium and alendronic acid preparations on disorders of structural and functional state of bone tissue in experimental animals at exogenic thyrotoxicosis was studied. It was defined that introduction of calcium preparations reduces bone mineral density loss in female rats with drug thyrotoxicosis, and combined use of calcium and alendronic acid prevents bone tissue loss regardless of thyrotoxicosis duration and presence of ovariectomy.

TDDFT calculations and photoacoustic spectroscopy experiments used to identify phenolic acid functional biomolecules in Brazilian tropical fruits in natura

Science.gov (United States)

Lourenço Neto, M.; Agra, K. L.; Suassuna Filho, J.; Jorge, F. E.

2018-03-01

Time-dependent density functional theory (TDDFT) calculations of electronic transitions have been widely used to determine molecular structures. The excitation wavelengths and oscillator strengths obtained with the hybrid exchange-correlation functional B3LYP in conjunction with the ADZP basis set are employed to simulate the UV-Vis spectra of eight phenolic acids. Experimental and theoretical UV-Vis spectra reported previously in the literature are compared with our results. The fast, sensitive and non-destructive technique of photoacoustic spectroscopy (PAS) is used to determine the UV-Vis spectra of four Brazilian tropical fresh fruits in natura. Then, the PAS along with the TDDFT results are for the first time used to investigate and identify the presence of phenolic acids in the fruits studied in this work. This theoretical method with this experimental technique show to be a powerful and cheap tool to detect the existence of phenolic acids in fruits, vegetables, cereals, and grains. Comparison with high performance liquid chromatography results, when available, is also carried out.

Flavonoids and phenolic acids from pearl millet (Pennisetum glaucum based foods and their functional implications

Directory of Open Access Journals (Sweden)

Vanisha S Nambiar

2012-07-01

Full Text Available Background: Pearl millet (Pennisetum glaucum, considered a poor man’s cereal, may be a repository of dietary antioxidants, especially flavonoids and phenolic acids, which provide bioactive mechanisms to reduce free radical induced oxidative stress and probably play a role in the prevention of ageing and various diseases associated with oxidative stress, such as cancer, cardiovascular, and neurodegenerative diseases.Objective: The present study focused on the identification of individual flavonoids and phenolic acids from seven commercial varieties of pearl millet and five samples of pearl millet-based traditional recipes of Banaskantha, Gujarat, India.Methods: Total phenols were determined by the Folin-Ciocalteu method, and individual polyphenol separation included the isolation and identification of (a flavonoids, (b phenolic acids, and (c glycoflavones involving interaction with diagnostic reagents and paper chromatographic separation of compounds and their UV-visible spectroscopic studies including hypsochromic and bathchromic shifts with reagents such as AlCl3, AlCl3/HCl, NaOMe, NaOAc,and NaOAc/H3PO3. Five traditional recipes consumed in the pearl millet producing belt of Banaskantha, Gujarat, India, were standardized in the laboratory and analyzed for phenol and individual flavonoids. Results: Total phenols in raw samples ranged from 268.5 - 420mg/100g of DW and 247.5 -Functional Foods in Health and Disease 2012, 2(7:251-264335mg/100g of DW in cooked recipes. The commonly identified flavonoids were tricin, acacetin, 3, 4 Di-OMe luteolin, and 4-OMe tricin. Five phenolic acids were identified: namely vanilic acid, syringic acid, melilotic acid, para-hydroxyl benzoic acid, and salicylic acid.Conclusion: The presence of flavonoids, such as tricin, acacetin, 3, 4 Di-OMe luteolin, and 4-OMe tricin, indicate the chemopreventive efficacy of pearl millet. They may be inversely related to mortality from coronary heart disease and to the incidence

Helminthosporic acid functions as an agonist for gibberellin receptor

OpenAIRE

Miyazaki, Sho; Jiang, Kai; Kobayashi, Masatomo; Asami, Tadao; Nakajima, Masatoshi

2017-01-01

Helminthosporol was isolated from a fungus, Helminthosporium sativum, as a natural plant growth regulator in 1963. It showed gibberellin-like bioactivity that stimulated the growth of the second leaf sheath of rice. After studying the structure–activity relationship between the compound and some synthesized analogs, it was found that helminthosporic acid (H-acid) has higher gibberellin-like activity and chemical stability than helminthosporol. In this study, we showed that (1) H-acid displays...

Changes in the carbohydrate and organic acid contents of tomatoes as a function of radiation dose and storage time

Energy Technology Data Exchange (ETDEWEB)

Kovacs, E [Kozponti Elelmiszeripari Kutato Intezet, Budapest (Hungary)

1974-01-01

Sugars and organic acids of tomatoes, variety Original Fruehrot, in different stages of development were examined by gas chromatography after silylation. Changes in the carbohydrate and organic acid content of half-ripe and ripe tomatoes were determined after treatment with different radiation doses (5, 15, 30, 60, 250 and 500 krad). Fructose, glucose, saccharose and malic acid could be detected in the tomato samples. The saccharose and malic acid contents of half-ripe tomatoes decreased as a result of irradiation with doses above 250 krad. In ripe tomatoes, the malic acid content fell most markedly under the influence of irradiation. The sugar content tended to decrease as a function of storage time, except for samples treated with 15 krad which usually delayed decomposition of the components tested. The effect of irradiation was more extensive in half-ripe tomatoes than in ripe ones.

Phospholipid metabolism and nuclear function: roles of the lipin family of phosphatidic acid phosphatases.

Science.gov (United States)

Siniossoglou, Symeon

2013-03-01

Phospholipids play important roles in nuclear function as dynamic building blocks for the biogenesis of the nuclear membrane, as well as signals by which the nucleus communicates with other organelles, and regulate a variety of nuclear events. The mechanisms underlying the nuclear roles of phospholipids remain poorly understood. Lipins represent a family of phosphatidic acid (PA) phosphatases that are conserved from yeasts to humans and perform essential functions in lipid metabolism. Several studies have identified key roles for lipins and their regulators in nuclear envelope organization, gene expression and the maintenance of lipid homeostasis in yeast and metazoans. This review discusses recent advances in understanding the roles of lipins in nuclear structure and function. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism. Copyright © 2012 Elsevier B.V. All rights reserved.

Surface functionalization of bioactive glasses with natural molecules of biological significance, Part I: Gallic acid as model molecule

Science.gov (United States)

Zhang, Xin; Ferraris, Sara; Prenesti, Enrico; Verné, Enrica

2013-12-01

Gallic acid (3,4,5-trihydroxybenzoic acid, GA) and its derivatives are a group of biomolecules (polyphenols) obtained from plants. They have effects which are potentially beneficial to heath, for example they are antioxidant, anticarcinogenic and antibacterial, as recently investigated in many fields such as medicine, food and plant sciences. The main drawbacks of these molecules are both low stability and bioavailability. In this research work the opportunity to graft GA to bioactive glasses is investigated, in order to deliver the undamaged biological molecule into the body, using the biomaterial surfaces as a localized carrier. GA was considered for functionalization since it is a good model molecule for polyphenols and presents several interesting biological activities, like antibacterial, antioxidant and anticarcinogenic properties. Two different silica based bioactive glasses (SCNA and CEL2), with different reactivity, were employed as substrates. UV photometry combined with the Folin&Ciocalteu reagent was adopted to test the concentration of GA in uptake solution after functionalization. This test verified how much GA consumption occurred with surface modification and it was also used on solid samples to test the presence of GA on functionalized glasses. XPS and SEM-EDS techniques were employed to characterize the modification of material surface properties and functional group composition before and after functionalization.

Physiological functions and pathogenic potential of uric acid: A review.

Science.gov (United States)

El Ridi, Rashika; Tallima, Hatem

2017-09-01

Uric acid is synthesized mainly in the liver, intestines and the vascular endothelium as the end product of an exogenous pool of purines, and endogenously from damaged, dying and dead cells, whereby nucleic acids, adenine and guanine, are degraded into uric acid. Mentioning uric acid generates dread because it is the established etiological agent of the severe, acute and chronic inflammatory arthritis, gout and is implicated in the initiation and progress of the metabolic syndrome. Yet, uric acid is the predominant anti-oxidant molecule in plasma and is necessary and sufficient for induction of type 2 immune responses. These properties may explain its protective potential in neurological and infectious diseases, mainly schistosomiasis. The pivotal protective potential of uric acid against blood-borne pathogens and neurological and autoimmune diseases is yet to be established.

Retinoic Acid-Related Orphan Receptors (RORs): Regulatory Functions in Immunity, Development, Circadian Rhythm, and Metabolism

Science.gov (United States)

Cook, Donald N.; Kang, Hong Soon; Jetten, Anton M.

2015-01-01

In this overview, we provide an update on recent progress made in understanding the mechanisms of action, physiological functions, and roles in disease of retinoic acid related orphan receptors (RORs). We are particularly focusing on their roles in the regulation of adaptive and innate immunity, brain function, retinal development, cancer, glucose and lipid metabolism, circadian rhythm, metabolic and inflammatory diseases and neuropsychiatric disorders. We also summarize the current status of ROR agonists and inverse agonists, including their regulation of ROR activity and their therapeutic potential for management of various diseases in which RORs have been implicated. PMID:26878025

Retinoic Acid-Related Orphan Receptors (RORs: Regulatory Functions in Immunity, Development, Circadian Rhythm, and Metabolism

Directory of Open Access Journals (Sweden)

Donald N. Cook

2015-12-01

Full Text Available In this overview, we provide an update on recent progress made in understanding the mechanisms of action, physiological functions, and roles in disease of retinoic acid related orphan receptors (RORs. We are particularly focusing on their roles in the regulation of adaptive and innate immunity, brain function, retinal development, cancer, glucose and lipid metabolism, circadian rhythm, metabolic and inflammatory diseases and neuropsychiatric disorders. We also summarize the current status of ROR agonists and inverse agonists, including their regulation of ROR activity and their therapeutic potential for management of various diseases in which RORs have been implicated.

High fluorescence emission of carboxylic acid functionalized polystyrene/BaTiO{sub 3} nanocomposites and rare earth metal complexes: Preparation and characterization

Energy Technology Data Exchange (ETDEWEB)

Cao, X. T.; Showkat, A. M.; Wang, Z.; Lim, K. T., E-mail: ktlim@pknu.ac.kr [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

2015-03-30

Noble fluorescence nanocomposite compound based on barium titanate nanoparticles (BTO), polystyrene (PSt), and terbium ion (Tb{sup 3+}) was synthesized by a combination of surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization, Friedel-Crafts alkylation reaction and coordinate chemistry. Initially, a modification of surface of BTO was conducted by an exchange process with S-benzyl S’-trimethoxysilylpropyltrithiocarbonate to create macro-initiator for polymerization of styrene. Subsequently, aryl carboxylic acid functionalized polystyrene grafted barium titanate (BTO-g-PSt-COOH) was generated by substitution reaction between 4-(Chloromethyl) benzoic acid and PSt chains. The coordination of the nanohybrids with Tb{sup 3+} ions afforded fluorescent Tb{sup 3+} tagged aryl carboxylic acid functionalized polystyrene grafted barium titanate (BTO-g-PSt-Tb{sup 3+}) complexes. Structure, morphology, and fluorescence properties of nanohybrid complexes were investigated by respective physical and spectral studies. FT-IR and SEM analyses confirmed the formation of BTO-g-PSt-Tb{sup 3+}nanohybrids. Furthermore, TGA profiles demonstrated the grafting of aryl carboxylic acid functionalized polystyrene on BTO surface. Optical properties of BTO-g-PSt-Tb{sup 3+} complexes were investigated by fluorescence spectroscopy.

Miscibility and specific interactions in blends of poly(n-vinyl-2-pyrrolidone) and acid functional polyester resins.

NARCIS (Netherlands)

Senatore, D.; Berix, M.J.A.; Laven, J.; Benthem, van R.A.T.M.; With, de G.; Mezari, B.; Magusin, P.C.M.M.

2008-01-01

Miscibility and intermol. interactions of novel blends of poly(N-vinyl-2-pyrrolidone) (PVP) and acid functional polyester resins (APE) were studied by use of Differential Scanning Calorimetry (DSC), Attenuated Total Reflectance Fourier Transform IR (ATR-FTIR), Cross-Polarization Magic Angle Spinning

Functional groups and reactivity of size-fractionated Aldrich humic acid

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Tadao, E-mail: tanaka.tadao26@jaea.go.jp [Nuclear Safety Research Center, Japan Atomic Energy Agency, Shirakata 2-4, Tokai, Naka, Ibaraki, 319-1195 (Japan)

2012-03-20

The complexation affinity of the Aldrich Chemicals humic acid with {sup 60}Co was examined with respect to molecular size of humic acid. Correlations between the affinity and the structures of humic acid were studied. At low humic acid concentration range, {sup 60}Co was interacted with the humic acid of size fraction over 100k Da (HA(100<)). With increasing humic acid concentration, the {sup 60}Co was preferentially interacted with the 30k-100k Da of humic acid (HA(30-100)). Fractionated HA(100<) and HA(30-100) were characterized from their FTIR (Fourier Transform Infra-Red), {sup 13}C NMR spectral analyses and acid-base titration curves. The HA(10<) having aliphatic branched structure, smaller amount of COOH group and large proton exchangeable capacity, seem to show low covalent bonding nature and high ion exchangeability in the complexation. In addition, steric hindrance may affect on the complexation, by winding up like random coils from the branched structure. The HA(30-100) is dominated with the aromatic COOH group and OH group and it may preferentially coordinate to {sup 60}Co by covalent binding. These presumptions were supported by XPS analysis, in which the biding energy of cobalt-humates was discussed.

Phenylboronic acid functionalized reduced graphene oxide based fluorescence nano sensor for glucose sensing

Energy Technology Data Exchange (ETDEWEB)

Basiruddin, SK; Swain, Sarat K., E-mail: swainsk2@yahoo.co.in

2016-01-01

Reduced graphene has emerged as promising tools for detection based application of biomolecules as it has high surface area with strong fluorescence quenching property. We have used the concept of fluorescent quenching property of reduced graphene oxide to the fluorescent probes which are close vicinity of its surface. In present work, we have synthesized fluorescent based nano-sensor consist of phenylboronic acid functionalized reduced graphene oxide (rGO–PBA) and di-ol modified fluorescent probe for detection of biologically important glucose molecules. This fluorescent graphene based nano-probe has been characterized by high resolution transmission electron microscope (HRTEM), Atomic force microscope (AFM), UV–visible, Photo-luminescence (PL) and Fourier transformed infrared (FT-IR) spectroscopy. Finally, using this PBA functionalized reduced GO based nano-sensor, we were able to detect glucose molecule in the range of 2 mg/mL to 75 mg/mL in aqueous solution of pH 7.4. - Highlights: • Easy and simple synthesis of PBA functionalized reduced GO based nano probe. • PBA functionalized reduced GO graphene based nano-probes are characterized. • PBA functionalized reduced GO nano probe is used to detect glucose molecules. • It is very cost-effective and enzyme-free detection of glucose in solution.

Design of an effective bifunctional catalyst organotriphosphonic acid-functionalized ferric alginate (ATMP-FA) and optimization by Box-Behnken model for biodiesel esterification synthesis of oleic acid over ATMP-FA.

Science.gov (United States)

Liu, Wei; Yin, Ping; Liu, Xiguang; Qu, Rongjun

2014-12-01

Biodiesel production has become an intense research area because of rapidly depleting energy reserves and increasing petroleum prices together with environmental concerns. This paper focused on the optimization of the catalytic performance in the esterification reaction of oleic acid for biodiesel production over the bifunctional catalyst organotriphosphonic acid-functionalized ferric alginate ATMP-FA. The reaction parameters including catalyst amount, ethanol to oleic acid molar ratio and reaction temperature have been optimized by response surface methodology (RSM) using the Box-Behnken model. It was found that the reaction temperature was the most significant factor, and the best conversion ratio of oleic acid could reach 93.17% under the reaction conditions with 9.53% of catalyst amount and 8.62:1 of ethanol to oleic acid molar ratio at 91.0 °C. The research results show that two catalytic species could work cooperatively to promote the esterification reaction, and the bifunctional ATMP-FA is a potential catalyst for biodiesel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ursodeoxycholic acid suppresses eosinophilic airway inflammation by inhibiting the function of dendritic cells through the nuclear farnesoid X receptor.

Science.gov (United States)

Willart, M A M; van Nimwegen, M; Grefhorst, A; Hammad, H; Moons, L; Hoogsteden, H C; Lambrecht, B N; Kleinjan, A

2012-12-01

Ursodeoxycholic acid (UDCA) is the only known beneficial bile acid with immunomodulatory properties. Ursodeoxycholic acid prevents eosinophilic degranulation and reduces eosinophil counts in primary biliary cirrhosis. It is unknown whether UDCA would also modulate eosinophilic inflammation outside the gastrointestinal (GI) tract, such as eosinophilic airway inflammation seen in asthma. The working mechanism for its immunomodulatory effect is unknown. The immunosuppressive features of UDCA were studied in vivo, in mice, in an ovalbumin (OVA)-driven eosinophilic airway inflammation model. To study the mechanism of action of UDCA, we analyzed the effect of UDCA on eosinophils, T cells, and dendritic cell (DCs). DC function was studied in greater detail, focussing on migration and T-cell stimulatory strength in vivo and interaction with T cells in vitro as measured by time-lapse image analysis. Finally, we studied the capacity of UDCA to influence DC/T cell interaction. Ursodeoxycholic acid treatment of OVA-sensitized mice prior to OVA aerosol challenge significantly reduced eosinophilic airway inflammation compared with control animals. DCs expressed the farnesoid X receptor for UDCA. Ursodeoxycholic acid strongly promoted interleukin (IL)-12 production and enhanced the migration in DCs. The time of interaction between DCs and T cells was sharply reduced in vitro by UDCA treatment of the DCs resulting in a remarkable T-cell cytokine production. Ursodeoxycholic acid-treated DCs have less capacity than saline-treated DCs to induce eosinophilic inflammation in vivo in Balb/c mice. Ursodeoxycholic acid has the potency to suppress eosinophilic inflammation outside the GI tract. This potential comprises to alter critical function of DCs, in essence, the effect of UDCA on DCs through the modulation of the DC/T cell interaction. © 2012 John Wiley & Sons A/S.

Functional analysis of free fatty acid receptor GPR120 in human eosinophils: implications in metabolic homeostasis.

Science.gov (United States)

Konno, Yasunori; Ueki, Shigeharu; Takeda, Masahide; Kobayashi, Yoshiki; Tamaki, Mami; Moritoki, Yuki; Oyamada, Hajime; Itoga, Masamichi; Kayaba, Hiroyuki; Omokawa, Ayumi; Hirokawa, Makoto

2015-01-01

Recent evidence has shown that eosinophils play an important role in metabolic homeostasis through Th2 cytokine production. GPR120 (FFA4) is a G protein-coupled receptor (GPCR) for long-chain fatty acids that functions as a regulator of physiological energy metabolism. In the present study, we aimed to investigate whether human eosinophils express GPR120 and, if present, whether it possesses a functional capacity on eosinophils. Eosinophils isolated from peripheral venous blood expressed GPR120 at both the mRNA and protein levels. Stimulation with a synthetic GPR120 agonist, GW9508, induced rapid down-regulation of cell surface expression of GPR120, suggesting ligand-dependent receptor internalization. Although GPR120 activation did not induce eosinophil chemotactic response and degranulation, we found that GW9508 inhibited eosinophil spontaneous apoptosis and Fas receptor expression. The anti-apoptotic effect was attenuated by phosphoinositide 3-kinase (PI3K) inhibitors and was associated with inhibition of caspase-3 activity. Eosinophil response investigated using ELISpot assay indicated that stimulation with a GPR120 agonist induced IL-4 secretion. These findings demonstrate the novel functional properties of fatty acid sensor GPR120 on human eosinophils and indicate the previously unrecognized link between nutrient metabolism and the immune system.

Adsorptive detoxification of fermentation inhibitors in acid pretreated liquor using functionalized polymer designed by molecular simulation.

Science.gov (United States)

Devendra, Leena P; Pandey, Ashok

2017-11-01

Acid pretreatment is the most common method employed in the lignocellulosic biorefinery leading to the separation of pentose and hexose sugar. The liquor obtained after pretreatment (acid pretreatment liquor or APL) needs to be detoxified prior to fermentation. The aim of this study was to design functional groups on a polymer matrix which are selective in their interaction to inhibitors with little or no specificity to sugars. Molecular modeling was used as a tool to design a suitable adsorbent for selective adsorption of inhibitors from a complex mixture of APL. Phenyl glycine-p-sulfonic acid loaded on chloromethylated polystyrene polymer was designed as an adsorbent for selective interaction with inhibitors. Experimental verification of the selectivity was successfully achieved. The current study provides insights on the adsorptive separation processes at the molecular level by design of specific adsorbent which can be tailor made for the better selectivity of the desired component.

Changes in the carbohydrate and organic acid contents of tomatoes as a function of radiation dose and storage time

International Nuclear Information System (INIS)

Kovacs, E.

1974-01-01

Sugars and organic acids of tomatoes, variety Original Fruehrot, in different stages of development were examined by gas chromatography after silylation. Changes in the carbohydrate and organic acid content of half-ripe and ripe tomatoes were determined after treatment with different radiation doses (5, 15, 30, 60, 250 and 500 krad). Fructose, glucose, saccharose and malic acid could be detected in the tomato samples. The saccharose and malic acid contents of half-ripe tomatoes decreased as a result of irradiation with doses above 250 krad. In ripe tomatoes, the malic acid content fell most markedly under the influence of irradiation. The sugar content tended to decrease as a function of storage time, except for samples treated with 15 krad which usually delayed decomposition of the components tested. The effect of irradiation was more extensive in half-ripe tomatoes than in ripe ones. (F.J.)

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

International Nuclear Information System (INIS)

Bloemen, Maarten; Brullot, Ward; Luong, Tai Thien; Geukens, Nick; Gils, Ann; Verbiest, Thierry

2012-01-01

Superparamagnetic iron oxide nanoparticles can provide multiple benefits for biomedical applications in aqueous environments such as magnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality water-dispersible nanoparticles around 10 nm in size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.

NPPD: A Protein-Protein Docking Scoring Function Based on Dyadic Differences in Networks of Hydrophobic and Hydrophilic Amino Acid Residues

Directory of Open Access Journals (Sweden)

Edward S. C. Shih

2015-03-01

Full Text Available Protein-protein docking (PPD predictions usually rely on the use of a scoring function to rank docking models generated by exhaustive sampling. To rank good models higher than bad ones, a large number of scoring functions have been developed and evaluated, but the methods used for the computation of PPD predictions remain largely unsatisfactory. Here, we report a network-based PPD scoring function, the NPPD, in which the network consists of two types of network nodes, one for hydrophobic and the other for hydrophilic amino acid residues, and the nodes are connected when the residues they represent are within a certain contact distance. We showed that network parameters that compute dyadic interactions and those that compute heterophilic interactions of the amino acid networks thus constructed allowed NPPD to perform well in a benchmark evaluation of 115 PPD scoring functions, most of which, unlike NPPD, are based on some sort of protein-protein interaction energy. We also showed that NPPD was highly complementary to these energy-based scoring functions, suggesting that the combined use of conventional scoring functions and NPPD might significantly improve the accuracy of current PPD predictions.

Synthesis of New Functionalized Citric Acid-based Dendrimers as Nanocarrier Agents for Drug Delivery

Directory of Open Access Journals (Sweden)

Sanaz Motamedi

2011-06-01

Full Text Available Introduction: Citric acid-polyethylene glycol-citric acid (CPEGC triblock dendrimers can serve as potential delivery systems. Methods: In this investigation, CPEGC triblock dendrimers were synthesized and then imidazole groups were conjugated onto the surface of the G1, G2 and G3 of the obtained dendrimers. In order to study the type of the interactions between the functionalized dendrimers and a drug molecule, Naproxen which contains acidic groups, was examined as a hydrophobic drug in which the interactions would be of the electrostatic kind between its acidic groups and the lone pair electrons of nitrogen atom in imidazole groups. The quantity of the trapped drug and also the amount of its release were measured with UV spectrometric method in pH 1, 7.4 and 10. The average diameter of the nanocarriers was measured by Dynamic Light Scattering (DLS technique Results: The size range of particles was determined to be 16-50 nm for different generations. The rate of the release increased in pH=10 in all generations due to the increase in Naproxen solubility and the hydrolysis of the esteric bonds in the mentioned pH. The results showed that the amount of the trapped drug increased with the increase in the generation of the dendrimer and pH. Conclusion: Based on our findings, we suggest CPEGC triblock dendrimers possess great potential to be used as drug/gene delivery system.

Two choices for the functionalization of silica nanoparticles with gallic acid: characterization of the nanomaterials and their antimicrobial activity against Paenibacillus larvae

Science.gov (United States)

Vico, Tamara A.; Arce, Valeria B.; Fangio, María F.; Gende, Liesel B.; Bertran, Celso A.; Mártire, Daniel O.; Churio, María S.

2016-11-01

Silica nanoparticles attached to gallic acid were synthesized from 7-nm diameter fumed silica particles by different functionalization methods involving the condensation of hydroxyl or carboxyl groups. The particles were characterized by thermal analyses and UV-vis, FTIR, NMR, and EPR spectroscopies. In comparison to free gallic acid, enhanced stability and increased antimicrobial activity against Paenibacillus larvae were found for the functionalized nanoparticles. Thus, both derivatization strategies result in improved properties of the natural polyphenol as antimicrobial agent for the treatment of honeybee pathologies.

Two choices for the functionalization of silica nanoparticles with gallic acid: characterization of the nanomaterials and their antimicrobial activity against Paenibacillus larvae

International Nuclear Information System (INIS)

Vico, Tamara A.; Arce, Valeria B.; Fangio, María F.; Gende, Liesel B.; Bertran, Celso A.; Mártire, Daniel O.; Churio, María S.

2016-01-01

Silica nanoparticles attached to gallic acid were synthesized from 7-nm diameter fumed silica particles by different functionalization methods involving the condensation of hydroxyl or carboxyl groups. The particles were characterized by thermal analyses and UV–vis, FTIR, NMR, and EPR spectroscopies. In comparison to free gallic acid, enhanced stability and increased antimicrobial activity against Paenibacillus larvae were found for the functionalized nanoparticles. Thus, both derivatization strategies result in improved properties of the natural polyphenol as antimicrobial agent for the treatment of honeybee pathologies.

Two choices for the functionalization of silica nanoparticles with gallic acid: characterization of the nanomaterials and their antimicrobial activity against Paenibacillus larvae

Energy Technology Data Exchange (ETDEWEB)

Vico, Tamara A. [Universidad Nacional de Mar del Plata, Departamento de Química, FCEyN/IFIMAR, CONICET (Argentina); Arce, Valeria B. [CONICET La Plata—CIC—UNLP, Centro de Investigaciones Ópticas (CIOp) (Argentina); Fangio, María F., E-mail: mfangio@mdp.edu.ar [Universidad Nacional de Mar del Plata, Departamento de Química, FCEyN/IFIMAR, CONICET (Argentina); Gende, Liesel B. [Universidad Nacional de Mar del Plata, Centro de Investigaciones en Abejas Sociales, FCEyN (Argentina); Bertran, Celso A. [University of Campinas, Chemistry Institute (Brazil); Mártire, Daniel O. [Universidad Nacional de La Plata, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CONICET (Argentina); Churio, María S., E-mail: schurio@mdp.edu.ar [Universidad Nacional de Mar del Plata, Departamento de Química, FCEyN/IFIMAR, CONICET (Argentina)

2016-11-15

Silica nanoparticles attached to gallic acid were synthesized from 7-nm diameter fumed silica particles by different functionalization methods involving the condensation of hydroxyl or carboxyl groups. The particles were characterized by thermal analyses and UV–vis, FTIR, NMR, and EPR spectroscopies. In comparison to free gallic acid, enhanced stability and increased antimicrobial activity against Paenibacillus larvae were found for the functionalized nanoparticles. Thus, both derivatization strategies result in improved properties of the natural polyphenol as antimicrobial agent for the treatment of honeybee pathologies.

Recent insights into the biological functions of liver fatty acid binding protein 1

Science.gov (United States)

Wang, GuQi; Bonkovsky, Herbert L.; de Lemos, Andrew; Burczynski, Frank J.

2015-01-01

Over four decades have passed since liver fatty acid binding protein (FABP)1 was first isolated. There are few protein families for which most of the complete tertiary structures, binding properties, and tissue occurrences are described in such detail and yet new functions are being uncovered for this protein. FABP1 is known to be critical for fatty acid uptake and intracellular transport and also has an important role in regulating lipid metabolism and cellular signaling pathways. FABP1 is an important endogenous cytoprotectant, minimizing hepatocyte oxidative damage and interfering with ischemia-reperfusion and other hepatic injuries. The protein may be targeted for metabolic activation through the cross-talk among many transcriptional factors and their activating ligands. Deficiency or malfunction of FABP1 has been reported in several diseases. FABP1 also influences cell proliferation during liver regeneration and may be considered as a prognostic factor for hepatic surgery. FABP1 binds and modulates the action of many molecules such as fatty acids, heme, and other metalloporphyrins. The ability to bind heme is another cytoprotective property and one that deserves closer investigation. The role of FABP1 in substrate availability and in protection from oxidative stress suggests that FABP1 plays a pivotal role during intracellular bacterial/viral infections by reducing inflammation and the adverse effects of starvation (energy deficiency). PMID:26443794

Comparative nucleic acid transfection efficacy in primary hepatocytes for gene silencing and functional studies

Directory of Open Access Journals (Sweden)

Morral Núria

2011-01-01

Full Text Available Abstract Background Primary hepatocytes are the best resource for in vitro studies directed at understanding hepatic processes at the cellular and molecular levels, necessary for novel drug development to treat highly prevalent diseases such as non-alcoholic steatohepatitis, cardiovascular disease and type 2 diabetes. There is a need to identify simple methods to genetically manipulate primary hepatocytes and conduct functional studies with plasmids, small interfering RNA (siRNA or microRNA (miRNA. New lipofection reagents are available that have the potential to yield higher levels of transfection with reduced toxicity. Findings We have tested several liposome-based transfection reagents used in molecular biology research. We show that transfection efficiency with one of the most recently developed formulations, Metafectene Pro, is high with plasmid DNA (>45% cells as well as double stranded RNA (>90% with siRNA or microRNA. In addition, negligible cytotoxicity was present with all of these nucleic acids, even if cells were incubated with the DNA:lipid complex for 16 hours. To provide the proof of concept that these conditions can be used not only for overexpression of a gene of interest, but also in RNA interference applications, we targeted two liver expressed genes, Sterol Regulatory Element-Binding Protein-1 and Fatty Acid Binding Protein 5 using plasmid-mediated short hairpin RNA expression. In addition, similar transfection conditions were used to optimally deliver siRNA and microRNA. Conclusions We have identified a lipid-based reagent for primary hepatocyte transfection of nucleic acids currently used in molecular biology laboratories. The conditions described here can be used to expedite a large variety of research applications, from gene function studies to microRNA target identification.

Effect of functional monomers in all-in-one adhesive systems on formation of enamel/dentin acid-base resistant zone.

Science.gov (United States)

Nikaido, Toru; Ichikawa, Chiaki; Li, Na; Takagaki, Tomohiro; Sadr, Alireza; Yoshida, Yasuhiro; Suzuki, Kazuomi; Tagami, Junji

2011-01-01

This study aimed at evaluating the effect of functional monomers in all-in-one adhesive systems on formation of acid-base resistant zone (ABRZ) in enamel and dentin. Experimental adhesive systems containing one of three functional monomers; MDP, 3D-SR and 4-META were applied to enamel or dentin surface and light-cured. A universal resin composite was then placed. The specimens were subjected to a demineralizing solution (pH 4.5) and 5% NaClO for acid-base challenge and then observed by SEM. The ABRZ was clearly observed in both enamel and dentin interfaces. However, enamel ABRZ was thinner than dentin ABRZ in all adhesives. Morphology of the ABRZ was different between enamel and dentin, and also among the adhesives. Funnel-shaped erosion was observed only in the enamel specimen with the 4-META adhesive. The formation of enamel/dentin ABRZ was confirmed in all adhesives, but the morphology was influenced by the functional monomers.

Identification and Functional Characterization of Genes Encoding Omega-3 Polyunsaturated Fatty Acid Biosynthetic Activities from Unicellular Microalgae

Directory of Open Access Journals (Sweden)

Royah Vaezi

2013-12-01

Full Text Available In order to identify novel genes encoding enzymes involved in the biosynthesis of nutritionally important omega-3 long chain polyunsaturated fatty acids, a database search was carried out in the genomes of the unicellular photoautotrophic green alga Ostreococcus RCC809 and cold-water diatom Fragilariopsis cylindrus. The search led to the identification of two putative “front-end” desaturases (Δ6 and Δ4 from Ostreococcus RCC809 and one Δ6-elongase from F. cylindrus. Heterologous expression of putative open reading frames (ORFs in yeast revealed that the encoded enzyme activities efficiently convert their respective substrates: 54.1% conversion of α-linolenic acid for Δ6-desaturase, 15.1% conversion of 22:5n-3 for Δ4-desaturase and 38.1% conversion of γ-linolenic acid for Δ6-elongase. The Δ6-desaturase from Ostreococcus RCC809 displays a very strong substrate preference resulting in the predominant synthesis of stearidonic acid (C18:4Δ6,9,12,15. These data confirm the functional characterization of omega-3 long chain polyunsaturated fatty acid biosynthetic genes from these two species which have until now not been investigated for such activities. The identification of these new genes will also serve to expand the repertoire of activities available for metabolically engineering the omega-3 trait in heterologous hosts as well as providing better insights into the synthesis of eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA in marine microalgae.

Biological Functions of ilvC in Branched-Chain Fatty Acid Synthesis and Diffusible Signal Factor Family Production in Xanthomonas campestris

Directory of Open Access Journals (Sweden)

Kai-Huai Li

2017-12-01

Full Text Available In bacteria, the metabolism of branched-chain amino acids (BCAAs is tightly associated with branched-chain fatty acids (BCFAs synthetic pathways. Although previous studies have reported on BCFAs biosynthesis, more detailed associations between BCAAs metabolism and BCFAs biosynthesis remain to be addressed. In this study, we deleted the ilvC gene, which encodes ketol-acid reductoisomerase in the BCAAs synthetic pathway, from the Xanthomonas campestris pv. campestris (Xcc genome. We characterized gene functions in BCFAs biosynthesis and production of the diffusible signal factor (DSF family signals. Disruption of ilvC caused Xcc to become auxotrophic for valine and isoleucine, and lose the ability to synthesize BCFAs via carbohydrate metabolism. Furthermore, ilvC mutant reduced the ability to produce DSF-family signals, especially branched-chain DSF-family signals, which might be the main reason for Xcc reduction of pathogenesis toward host plants. In this report, we confirmed that BCFAs do not have major functions in acclimatizing Xcc cells to low temperatures.

Mechanistic Investigation of Molybdate-Catalysed Transfer Hydrodeoxygenation.

Science.gov (United States)

Larsen, Daniel B; Petersen, Allan R; Dethlefsen, Johannes R; Teshome, Ayele; Fristrup, Peter

2016-11-07

The molybdate-catalysed transfer hydrodeoxygenation (HDO) of benzyl alcohol to toluene driven by oxidation of the solvent isopropyl alcohol to acetone has been investigated by using a combination of experimental and computational methods. A Hammett study that compared the relative rates for the transfer HDO of five para-substituted benzylic alcohols was carried out. Density-functional theory (DFT) calculations suggest a transition state with significant loss of aromaticity contributes to the lack of linearity observed in the Hammett study. The transfer HDO could also be carried out in neat PhCH 2 OH at 175 °C. Under these conditions, PhCH 2 OH underwent disproportionation to yield benzaldehyde, toluene, and significant amounts of bibenzyl. Isotopic-labelling experiments (using PhCH 2 OD and PhCD 2 OH) showed that incorporation of deuterium into the resultant toluene originated from the α position of benzyl alcohol, which is in line with the mechanism suggested by the DFT study. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proteomic characterization of the acid tolerance response in Lactobacillus delbrueckii subsp. bulgaricus CAUH1 and functional identification of a novel acid stress-related transcriptional regulator Ldb0677.

Science.gov (United States)

Zhai, Zhengyuan; Douillard, François P; An, Haoran; Wang, Guohong; Guo, Xinghua; Luo, Yunbo; Hao, Yanling

2014-06-01

To overcome the deleterious effects of acid stress, Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) elicits an adaptive response to acid stress. In this study, proteomics approach complemented by transcriptional analysis revealed some cellular changes in L. bulgaricus CAUH1 during acid adaptation. We observed an increase of glycolysis-associated proteins, promoting an optimal utilization of carbohydrates. Also, rerouting of the pyruvate metabolism to fatty acid biosynthesis was observed, indicating a possible modification of the cell membrane rigidity and impermeability. In addition, expression of ribosomal protein S1 (RpsA) was repressed; however, the expression of EF-Tu, EF-G and TypA was up-regulated at both protein and transcript levels. This suggests a reduction of protein synthesis in response to acid stress along with possible enhancement of the translational accuracy and protein folding. It is noteworthy that the putative transcriptional regulator Ldb0677 was 1.84-fold up-regulated. Heterologous expression of Ldb0677 was shown to significantly enhance acid resistance in host strain Lactococcus lactis. To clarify its role in transcriptional regulation network, the DNA-binding specificity of Ldb0677 was determined using bacterial one-hybrid and electrophoretic mobility shift assay. The identification of a binding motif (SSTAGACR) present in the promoter regions of 22 genes indicates that it might function as a major regulator in acid stress response in L. bulgaricus. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Lactic acid bacteria: microbiological and functional aspects

National Research Council Canada - National Science Library

Lahtinen, Sampo

2012-01-01

"Updated with the substantial progress made in lactic acid and bacteria research since the third edition, this fourth volume discusses improved insights in genetics and new molecular biological techniques...

Co-production of functional exopolysaccharides and lactic acid by Lactobacillus kefiranofaciens originated from fermented milk, kefir.

Science.gov (United States)

Cheirsilp, Benjamas; Suksawang, Suwannee; Yeesang, Jarucha; Boonsawang, Piyarat

2018-01-01

Kefiran is a functional exopolysaccharide produced by Lactobacillus kefiranofaciens originated from kefir, traditional fermented milk in the Caucasian Mountains, Russia. Kefiran is attractive as thickeners, stabilizers, emulsifiers, gelling agents and also has antimicrobial and antitumor activity. However, the production costs of kefiran are still high mainly due to high cost of carbon and nitrogen sources. This study aimed to produce kefiran and its co-product, lactic acid, from low-cost industrial byproducts. Among the sources tested, whey lactose (at 2% sugar concentration) and spent yeast cells hydrolysate (at 6 g-nitrogen/L) gave the highest kefiran of 480 ± 21 mg/L along with lactic acid of 20.1 ± 0.2 g/L. The combination of these two sources and initial pH were optimized through Response Surface Methodology. With the optimized medium, L. kefiranofaciens produced more kefiran and lactic acid up to 635 ± 7 mg/L and 32.9 ± 0.7 g/L, respectively. When the pH was controlled to alleviate the inhibition from acidic pH, L. kefiranofaciens could consume all sugars and produced kefiran and lactic acid up to 1693 ± 29 mg/L and 87.49 ± 0.23 g/L, respectively. Moreover, the fed-batch fermentation with intermittent adding of whey lactose improved kefiran and lactic acid productions up to 2514 ± 93 mg/L and 135 ± 1.75 g/L, respectively. These results indicate the promising approach to economically produce kefiran and lactic acid from low-cost nutrient sources.

Investigating tautomeric polymorphism in crystalline anthranilic acid using terahertz spectroscopy and solid-state density functional theory.

Science.gov (United States)

Delaney, Sean P; Witko, Ewelina M; Smith, Tiffany M; Korter, Timothy M

2012-08-02

Terahertz spectroscopy is sensitive to the interactions between molecules in the solid-state and recently has emerged as a new analytical tool for investigating polymorphism. Here, this technique is applied for the first time to the phenomenon of tautomeric polymorphism where the crystal structures of anthranilic acid (2-aminobenzoic acid) have been investigated. Three polymorphs of anthranilic acid (denoted Forms I, II and III) were studied using terahertz spectroscopy and the vibrational modes and relative polymorph stabilities analyzed using solid-state density functional theory calculations augmented with London dispersion force corrections. Form I consists of both neutral and zwitterionic molecules and was found to be the most stable polymorph as compared to Forms II and III (both containing only neutral molecules). The simulations suggest that a balance between steric interactions and electrostatic forces is responsible for the favoring of the mixed neutral/zwitterion solid over the all neutral or all zwitterion crystalline arrangements.

Structural analysis of binding functionality of folic acid-PEG dendrimers against folate receptor.

Science.gov (United States)

Sampogna-Mireles, Diana; Araya-Durán, Ingrid D; Márquez-Miranda, Valeria; Valencia-Gallegos, Jesús A; González-Nilo, Fernando D

2017-03-01

Dendrimers functionalized with folic acid (FA) are drug delivery systems that can selectively target cancer cells with folate receptors (FR-α) overexpression. Incorporation of polyethylene glycol (PEG) can enhance dendrimers solubility and pharmacokinetics, but ligand-receptor binding must not be affected. In this work we characterized, at atomic level, the binding functionality of conventional site-specific dendrimers conjugated with FA with PEG 750 or PEG 3350 as a linker. After Molecular Dynamics simulation, we observed that both PEG's did not interfere over ligand-receptor binding functionality. Although binding kinetics could be notably affected, the folate fragment from both dendrimers remained exposed to the solvent before approaching selectively to FR-α. PEG 3350 provided better solubility and protection from enzymatic degradation to the dendrimer than PEG 750. Also, FA-PEG3350 dendrimer showed a slightly better interaction with FR-α than FA-PEG750 dendrimer. Therefore, theoretical evidence supports that both dendrimers are suitable as drug delivery systems for cancer therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

Is Lactate an undervalued functional component of lactic acid bacteria-fermented food products?

Directory of Open Access Journals (Sweden)

Graciela eGarrote

2015-06-01

Full Text Available Although it has been traditionally regarded as an intermediate of carbon metabolism and major component of fermented dairy products contributing to organoleptic and antimicrobial properties of food, there is evidence gathered in recent years that lactate has bioactive properties that may be responsible of broader properties of functional foods. Lactate can regulate critical functions of several key players of the immune system such as macrophages and dendritic cells, being able to modulate inflammatory activation of epithelial cells as well. Intraluminal levels of lactate derived from fermentative metabolism of lactobacilli have been shown to modulate inflammatory environment in intestinal mucosa. The molecular mechanisms responsible to these functions, including histone deacetylase dependent-modulation of gene expression and signalling through G-protein coupled receptors have started to be described. Since lactate is a major fermentation product of several bacterial families with probiotic properties, we here propose that it may contribute to some of the properties attributed to these microorganisms and in a larger view, to the properties of food products fermented by lactic acid bacteria.

Accumulation, selection and covariation of amino acids in sieve tube sap of tansy (Tanacetum vulgare) and castor bean (Ricinus communis): evidence for the function of a basic amino acid transporter and the absence of a γ-amino butyric acid transporter.

Science.gov (United States)

Bauer, Susanne N; Nowak, Heike; Keller, Frank; Kallarackal, Jose; Hajirezaei, Mohamad-Reza; Komor, Ewald

2014-09-01

Sieve tube sap was obtained from Tanacetum by aphid stylectomy and from Ricinus after apical bud decapitation. The amino acids in sieve tube sap were analyzed and compared with those from leaves. Arginine and lysine accumulated in the sieve tube sap of Tanacetum more than 10-fold compared to the leaf extracts and they were, together with asparagine and serine, preferably selected into the sieve tube sap, whereas glycine, methionine/tryptophan and γ-amino butyric acid were partially or completely excluded. The two basic amino acids also showed a close covariation in sieve tube sap. The acidic amino acids also grouped together, but antagonistic to the other amino acids. The accumulation ratios between sieve tube sap and leaf extracts were smaller in Ricinus than in Tanacetum. Arginine, histidine, lysine and glutamine were enriched and preferentially loaded into the phloem, together with isoleucine and valine. In contrast, glycine and methionine/tryptophan were partially and γ-amino butyric acid almost completely excluded from sieve tube sap. The covariation analysis grouped arginine together with several neutral amino acids. The acidic amino acids were loaded under competition with neutral amino acids. It is concluded from comparison with the substrate specificities of already characterized plant amino acid transporters, that an AtCAT1-like transporter functions in phloem loading of basic amino acids, whereas a transporter like AtGAT1 is absent in phloem. Although Tanacetum and Ricinus have different minor vein architecture, their phloem loading specificities for amino acids are relatively similar. © 2014 Scandinavian Plant Physiology Society.

Dose-response functions for effects of acidic precipitation on vegetation

Energy Technology Data Exchange (ETDEWEB)

Jacobson, J S; Troiano, J J

1983-01-01

Research on the effect of sulfuric and nitric acids, as well as other substances, in rain on plant growth has focused on quantifying the relationship between doses of acids in precipitation and plant response. After eight years, there has been no direct demonstration of harmful effects to plants by ambient acidic rain in North America, and there remains considerable uncertainty about the potential risk to cultivated and native plants. Current efforts to describe the relationships between dose of acidity and effects on plants need better experimental approaches if the results are to be more relevant to actual field situations. Mechanistic models that describe the physiological and biochemical basis for effects of acidic rain on plants will be needed to provide confidence in the predictions of plant response. 34 references, 1 figure.

Characterization of acid functional groups of carbon dots by nonlinear regression data fitting of potentiometric titration curves

Science.gov (United States)

Alves, Larissa A.; de Castro, Arthur H.; de Mendonça, Fernanda G.; de Mesquita, João P.

2016-05-01

The oxygenated functional groups present on the surface of carbon dots with an average size of 2.7 ± 0.5 nm were characterized by a variety of techniques. In particular, we discussed the fit data of potentiometric titration curves using a nonlinear regression method based on the Levenberg-Marquardt algorithm. The results obtained by statistical treatment of the titration curve data showed that the best fit was obtained considering the presence of five Brønsted-Lowry acids on the surface of the carbon dots with constant ionization characteristics of carboxylic acids, cyclic ester, phenolic and pyrone-like groups. The total number of oxygenated acid groups obtained was 5 mmol g-1, with approximately 65% (∼2.9 mmol g-1) originating from groups with pKa titrated and initial concentration of HCl solution. Finally, we believe that the methodology used here, together with other characterization techniques, is a simple, fast and powerful tool to characterize the complex acid-base properties of these so interesting and intriguing nanoparticles.

Density functional theory fragment descriptors to quantify the reactivity of a molecular family: application to amino acids.

Science.gov (United States)

Senet, P; Aparicio, F

2007-04-14

By using the exact density functional theory, one demonstrates that the value of the local electronic softness of a molecular fragment is directly related to the polarization charge (Coulomb hole) induced by a test electron removed (or added) from (at) the fragment. Our finding generalizes to a chemical group a formal relation between these molecular descriptors recently obtained for an atom in a molecule using an approximate atomistic model [P. Senet and M. Yang, J. Chem. Sci. 117, 411 (2005)]. In addition, a practical ab initio computational scheme of the Coulomb hole and related local descriptors of reactivity of a molecular family having in common a similar fragment is presented. As a blind test, the method is applied to the lateral chains of the 20 isolated amino acids. One demonstrates that the local softness of the lateral chain is a quantitative measure of the similarity of the amino acids. It predicts the separation of amino acids in different biochemical groups (aliphatic, basic, acidic, sulfur contained, and aromatic). The present approach may find applications in quantitative structure activity relationship methodology.

Application of citric acid in acid stimulation treatments

Energy Technology Data Exchange (ETDEWEB)

Alkhaldi, M.H.; Sarma, H.K. [Adelaide Univ., Adelaide (Australia); Nasr-el-Din, H.A. [Texas A and M Univ., College Station, TX (United States)

2009-07-01

A rotating disk apparatus was used to investigate mass transfer during the reaction of citric acid with calcite. The study evaluated the effects of initial acid concentrations, temperature, and disk rotational speed on the effective diffusion coefficient of citric acid. The diffusion coefficient was calculated at 25, 40, and 50 degrees C using various citric acid concentrations. The study indicated that the coefficient was a function of the interactions between calcium citrate precipitation and counter calcium ions. At high acid concentrations, the effects of calcium citrate precipitation and counter calcium ions were significant. The calculated citric acid diffusion coefficients were not comparable with measured effective diffusion coefficients using the rotating disk. At lower initial citric acid concentrations, the effects of both calcium citrate precipitation and counter calcium ions on citric acid diffusivity were minimal. It was concluded that temperature effects on the diffusion coefficient followed Arrhenius law. Activation energy was equal to 37.9 kJ/mol. 34 refs., 4 tabs., 13 figs.

Functional microorganisms for functional food quality.

Science.gov (United States)

Gobbetti, M; Cagno, R Di; De Angelis, M

2010-09-01

Functional microorganisms and health benefits represent a binomial with great potential for fermented functional foods. The health benefits of fermented functional foods are expressed either directly through the interactions of ingested live microorganisms with the host (probiotic effect) or indirectly as the result of the ingestion of microbial metabolites synthesized during fermentation (biogenic effect). Since the importance of high viability for probiotic effect, two major options are currently pursued for improving it--to enhance bacterial stress response and to use alternative products for incorporating probiotics (e.g., ice cream, cheeses, cereals, fruit juices, vegetables, and soy beans). Further, it seems that quorum sensing signal molecules released by probiotics may interact with human epithelial cells from intestine thus modulating several physiological functions. Under optimal processing conditions, functional microorganisms contribute to food functionality through their enzyme portfolio and the release of metabolites. Overproduction of free amino acids and vitamins are two classical examples. Besides, bioactive compounds (e.g., peptides, γ-amino butyric acid, and conjugated linoleic acid) may be released during food processing above the physiological threshold and they may exert various in vivo health benefits. Functional microorganisms are even more used in novel strategies for decreasing phenomenon of food intolerance (e.g., gluten intolerance) and allergy. By a critical approach, this review will aim at showing the potential of functional microorganisms for the quality of functional foods.

Proliferation related acidic leucine-rich protein PAL31 functions as a caspase-3 inhibitor

International Nuclear Information System (INIS)

Sun Weiyong; Kimura, Hiromichi; Hattori, Naka; Tanaka, Satoshi; Matsuyama, Shigemi; Shiota, Kunio

2006-01-01

Proliferation related acidic leucine-rich protein PAL31 (PAL31) is expressed in proliferating cells and consists of 272 amino acids with a tandem structure of leucine-rich repeats in the N-terminus and a highly acidic region with a putative nuclear localization signal in the C-terminus. We previously reported that PAL31 is required for cell cycle progression. In the present study, we found that the antisense oligonucleotide of PAL31 induced apoptosis to the transfected Nb2 cells. Stable transfectants, in which PAL31 was regulated by an inducible promoter, were generated to gain further insight into the signaling role of PAL31 in the regulation of apoptosis. Expression of PAL31 resulted in the marked rescue of Rat1 cells from etoposide and UV radiation-induced apoptosis and the cytoprotection was correlated with the levels of PAL31 protein. Thus, cytoprotection from apoptosis is a physiological function of PAL31. PAL31 can suppress caspase-3 activity but not cytochrome c release in vitro, indicating that PAL31 is a direct caspase-3 inhibitor. In conclusion, PAL31 is a multifunctional protein working as a cell cycle progression factor as well as a cell survival factor

In Vitro Effect of Fatty Acids Identified in the Plasma of Obese Adolescents on the Function of Pancreatic β-Cells

Directory of Open Access Journals (Sweden)

Claudia Velasquez

2017-05-01

Full Text Available BackgroundThe increase in circulating free fatty acid (FFA levels is a major factor that induces malfunction in pancreatic β-cells. We evaluated the effect of FFAs reconstituted according to the profile of circulating fatty acids found in obese adolescents on the viability and function of the murine insulinoma cell line (mouse insulinoma [MIN6].MethodsFrom fatty acids obtained commercially, plasma-FFA profiles of three different youth populations were reconstituted: obese with metabolic syndrome; obese without metabolic syndrome; and normal weight without metabolic syndrome. MIN6 cells were treated for 24 or 48 hours with the three FFA profiles, and glucose-stimulated insulin secretion, cell viability, mitochondrial function and antioxidant activity were evaluated.ResultsThe high FFA content and high polyunsaturated ω6/ω3 ratio, present in plasma of obese adolescents with metabolic syndrome had a toxic effect on MIN6 cell viability and function, increasing oxidative stress and decreasing glucose-dependent insulin secretion.ConclusionThese results could help to guide nutritional management of obese young individuals, encouraging the increase of ω-3-rich food consumption in order to reduce the likelihood of deterioration of β-cells and the possible development of type 2 diabetes mellitus.

Subtype-specific Modulation of Acid-sensing Ion Channel (ASIC) Function by 2-Guanidine-4-methylquinazoline*

Science.gov (United States)

Alijevic, Omar; Kellenberger, Stephan

2012-01-01

Acid-sensing ion channels (ASICs) are neuronal Na+-selective channels that are transiently activated by extracellular acidification. ASICs are involved in fear and anxiety, learning, neurodegeneration after ischemic stroke, and pain sensation. The small molecule 2-guanidine-4-methylquinazoline (GMQ) was recently shown to open ASIC3 at physiological pH. We have investigated the mechanisms underlying this effect and the possibility that GMQ may alter the function of other ASICs besides ASIC3. GMQ shifts the pH dependence of activation to more acidic pH in ASIC1a and ASIC1b, whereas in ASIC3 this shift goes in the opposite direction and is accompanied by a decrease in its steepness. GMQ also induces an acidic shift of the pH dependence of inactivation of ASIC1a, -1b, -2a, and -3. As a consequence, the activation and inactivation curves of ASIC3 but not other ASICs overlap in the presence of GMQ at pH 7.4, thereby creating a window current. At concentrations >1 mm, GMQ decreases maximal peak currents by reducing the unitary current amplitude. Mutation of residue Glu-79 in the palm domain of ASIC3, previously shown to be critical for channel opening by GMQ, disrupted the GMQ effects on inactivation but not activation. This suggests that this residue is involved in the consequences of GMQ binding rather than in the binding interaction itself. This study describes the mechanisms underlying the effects of a novel class of ligands that modulate the function of all ASICs as well as activate ASIC3 at physiological pH. PMID:22948146

Subtype-specific modulation of acid-sensing ion channel (ASIC) function by 2-guanidine-4-methylquinazoline.

Science.gov (United States)

Alijevic, Omar; Kellenberger, Stephan

2012-10-19

Acid-sensing ion channels (ASICs) are neuronal Na(+)-selective channels that are transiently activated by extracellular acidification. ASICs are involved in fear and anxiety, learning, neurodegeneration after ischemic stroke, and pain sensation. The small molecule 2-guanidine-4-methylquinazoline (GMQ) was recently shown to open ASIC3 at physiological pH. We have investigated the mechanisms underlying this effect and the possibility that GMQ may alter the function of other ASICs besides ASIC3. GMQ shifts the pH dependence of activation to more acidic pH in ASIC1a and ASIC1b, whereas in ASIC3 this shift goes in the opposite direction and is accompanied by a decrease in its steepness. GMQ also induces an acidic shift of the pH dependence of inactivation of ASIC1a, -1b, -2a, and -3. As a consequence, the activation and inactivation curves of ASIC3 but not other ASICs overlap in the presence of GMQ at pH 7.4, thereby creating a window current. At concentrations >1 mM, GMQ decreases maximal peak currents by reducing the unitary current amplitude. Mutation of residue Glu-79 in the palm domain of ASIC3, previously shown to be critical for channel opening by GMQ, disrupted the GMQ effects on inactivation but not activation. This suggests that this residue is involved in the consequences of GMQ binding rather than in the binding interaction itself. This study describes the mechanisms underlying the effects of a novel class of ligands that modulate the function of all ASICs as well as activate ASIC3 at physiological pH.

Functional nanoparticles exploit the bile acid pathway to overcome multiple barriers of the intestinal epithelium for oral insulin delivery

DEFF Research Database (Denmark)

Fan, Weiwei; Xia, Dengning; Zhu, Quanlei

2018-01-01

, especially to avoid lysosomal degradation, and basolateral release. Here, the functional material, deoxycholic acid-conjugated chitosan, is synthesized and loaded with the model protein drug insulin into deoxycholic acid-modified nanoparticles (DNPs). The DNPs designed in this study are demonstrated......Oral absorption of protein/peptide-loaded nanoparticles is often limited by multiple barriers of the intestinal epithelium. In addition to mucus translocation and apical endocytosis, highly efficient transepithelial absorption of nanoparticles requires successful intracellular trafficking...... to endolysosomal escape of DNPs. Additionally, DNPs can interact with a cytosolic ileal bile acid-binding protein that facilitates the intracellular trafficking and basolateral release of insulin. In rats, intravital two-photon microscopy also reveals that the transport of DNPs into the intestinal villi...

Successes and failures of DFT functionals in acid/base and redox reactions of organic and biochemical interest

OpenAIRE

Silva, Pedro J.; Ramos, Maria João

2011-01-01

The performance of 18 different DFT functionals in the prediction of absolute and relative energies of organic and biochemical acid/base and redox reactions was evaluated, using MP2 extrapolated to the complete basis set limit and CCSD(T)/aug-cc-pVTZ energies as benchmark. Absolute reduction energies were predicted with relatively large average errors (2–4 kcal mol−1) except for the best functional, PBE0 (1.3 ± 1.2 kcal mol−1). The DFT predictions of relative reduction energies afforded mean ...

The effect of acid hydrolysis on the technological functional properties of pinhão (Araucaria brasiliensis starch

Directory of Open Access Journals (Sweden)

Roberta Cruz Silveira Thys

2013-02-01

Full Text Available Technological functional properties of native and acid-thinned pinhão (seeds of Araucária angustifolia, Brazilian pine starches were evaluated and compared to those of native and acid-thinned corn starches. The starches were hydrolyzed (3.2 mol.L-1 HCl, 44 ºC, 6 hours and evaluated before and after the hydrolysis reaction in terms of formation, melting point and thermo-reversibility of gel starches, retrogradation (in a 30-day period and measurements every three days, paste freezing and thawing stability (after six freezing and thawing cycles, swelling power, and solubility. The results of light transmittance (% of pastes of native and acid-thinned pinhão starches was higher (lower tendency to retrogradation than that obtained for corn starches after similar storage period. Native pinhão starch (NPS presented lower syneresis than native corn starch (NCS when submitted to freeze-thaw cycles. The acid hydrolysis increased the syneresis of the two native varieties under storage at 5 ºC and after freezing and thawing cycles. The solubility of NPS was lower than that of native corn starch at 25, 50, and 70 ºC. However, for the acid-thinned pinhão starch (APS, this property was significantly higher (p < 0.05 when compared to that of acid-thinned corn starch (ACS. From the results obtained, it can be said that the acid treatment was efficient in producing a potential fat substitute from pinhão starch variety, but this ability must be further investigated.

Phosphinic acid functionalized carbon nanotubes for sensitive and selective sensing of chromium(VI)

Energy Technology Data Exchange (ETDEWEB)

Deep, Akash, E-mail: dr.akashdeep@csio.res.in; Sharma, Amit L.; Tuteja, Satish K.; Paul, A.K.

2014-08-15

Highlights: • SWCNTs have been conjugated with bis(2,4,4-trimethylpentyl) phosphinic acid (PA/d). • SWCNT-PA/d adduct is demonstrated for electrochemical sensing of Cr(VI). • Linear response is obtained for 0.01–10 ppb Cr(VI). • Sensitivity and the limit of detection are 35 ± 4 nA/ppb and 0.01 ppb, respectively. • Proposed sensing of Cr(VI) is selective with respect to many other metals. - Abstract: Single-walled carbon nanotubes (SWCNTs) have been functionalized with a phosphinic acid derivative ‘bis(2,4,4-trimethylpentyl) phosphinic acid’ (PA/d). It has been achieved by treating the chlorinated SWCNTs with PA/d at 80 °C. Successful functionalization and different nanomaterial properties have been investigated by UV–vis–NIR, FTIR, Raman spectroscopy, AFM and FE-SEM. PA/d conjugated SWCNTs (CNT–PA) are dispersible in some common organic solvents, e.g. CH{sub 2}Cl{sub 2}, DMF, CHCl{sub 3}, and THF. The ‘CNT–PA’ complex was spin-casted on boron doped silicon wafer. Thus fabricated sensing electrode is demonstrated for sensitive and selective electrochemical sensing of chromium(VI) ions. A linear response is obtained over a wide range of Cr(VI) concentration (0.01–10 ppb). The sensor's sensitivity and the limit of detection are observed to be 35 ± 4 nA/ppb and 0.01 ppb, respectively. The practical utility of the proposed sensor is demonstrated by determining the Cr(VI) concentration in an industrial effluent sample and an underground water sample.

Detection of Promyelocytic Leukemia/Retinoic Acid Receptor α (PML/RARα Fusion Gene with Functionalized Graphene Oxide

Directory of Open Access Journals (Sweden)

Hongwei Wang

2013-06-01

Full Text Available An attempt was made to use functionalized graphene oxide (GO to detect the Promyelocytic leukemia/Retinoic acid receptor α fusion gene (PML/RARα fusion gene, a marker gene of acute promyelocytic leukemia. The functionalized GO was prepared by chemical exfoliation method, followed by a polyethylene glycol grafting. It is found that the functionalized GO can selectively adsorb the fluorescein isothiocyanate (FITC-labeled single-stranded DNA probe and quench its fluorescence. The probe can be displaced by the PML/RARα fusion gene to restore the fluorescence, which can be detected by laser confocal microscopy and flow cytometry. These can be used to detect the presence of the PML/RARα fusion gene. This detection method is verified to be fast, simple and reliable.

Effect of Uric Acid-Lowering Agents on Endothelial Function: A Randomized, Double-Blind, Placebo-Controlled Trial.

Science.gov (United States)

Borgi, Lea; McMullan, Ciaran; Wohlhueter, Ann; Curhan, Gary C; Fisher, Naomi D; Forman, John P

2017-02-01

Higher levels of serum uric acid are independently associated with endothelial dysfunction, a mechanism for incident hypertension. Overweight/obese individuals are more prone to endothelial dysfunction than their lean counterparts. However, the effect of lowering serum uric acid on endothelial dysfunction in these individuals has not been examined thoroughly. In this randomized, double-blind, placebo-controlled trial of nonhypertensive, overweight, or obese individuals with higher serum uric acid (body mass index ≥25 kg/m 2 and serum uric acid ≥5.0 mg/dL), we assigned subjects to probenecid (500-1000 mg/d), allopurinol (300-600 mg/d), or matching placebo. The primary outcome was endothelium-dependent vasodilation measured by brachial artery ultrasound at baseline and 8 weeks. By the end of the trial, 47, 49, and 53 participants had been allocated to receive probenecid, allopurinol, and placebo, respectively. Mean serum uric acid levels significantly decreased in the probenecid (from 6.1 to 3.5 mg/dL) and allopurinol groups (from 6.1 to 2.9 mg/dL) but not in the placebo group (6.1 to 5.6 mg/dL). None of the interventions produced any significant change in endothelium-dependent vasodilation (probenecid, 7.4±5.1% at baseline and 8.3±5.1% at 8 weeks; allopurinol, 7.6±6.0% at baseline and 6.2±4.8% at 8 weeks; and placebo, 6.5±3.8% at baseline and 7.1±4.9% at 8 weeks). In this randomized, double-blind, placebo-controlled trial, uric acid lowering did not affect endothelial function in overweight or obese nonhypertensive individuals. These data do not support the hypothesis that uric acid is causally related to endothelial dysfunction, a potential mechanism for development of hypertension. © 2016 American Heart Association, Inc.

Insights into the Structure, Function, and Ligand Discovery of the Large Neutral Amino Acid Transporter 1, LAT1

Directory of Open Access Journals (Sweden)

Natesh Singh

2018-04-01

Full Text Available The large neutral amino acid transporter 1 (LAT1, or SLC7A5 is a sodium- and pH-independent transporter, which supplies essential amino acids (e.g., leucine, phenylalanine to cells. It plays an important role at the Blood–Brain Barrier (BBB where it facilitates the transport of thyroid hormones, pharmaceuticals (e.g., l-DOPA, gabapentin, and metabolites into the brain. Moreover, its expression is highly upregulated in various types of human cancer that are characterized by an intense demand for amino acids for growth and proliferation. Therefore, LAT1 is believed to be an important drug target for cancer treatment. With the crystallization of the arginine/agmatine antiporter (AdiC from Escherichia Coli, numerous homology models of LAT1 have been built to elucidate the substrate binding site, ligand–transporter interaction, and structure–function relationship. The use of these models in combination with molecular docking and experimental testing has identified novel chemotypes of ligands of LAT1. Here, we highlight the structure, function, transport mechanism, and homology modeling of LAT1. Additionally, results from structure–function studies performed on LAT1 are addressed, which have enhanced our knowledge of the mechanism of substrate binding and translocation. This is followed by a discussion on ligand- and structure-based approaches, with an emphasis on elucidating the molecular basis of LAT1 inhibition. Finally, we provide an exhaustive summary of different LAT1 inhibitors that have been identified so far, including the recently discovered irreversible covalent inhibitors.

Gallic acid grafting effect on delivery performance and antiglaucoma efficacy of antioxidant-functionalized intracameral pilocarpine carriers.

Science.gov (United States)

Chou, Shih-Feng; Luo, Li-Jyuan; Lai, Jui-Yang

2016-07-01

Functionalization of therapeutic carrier biomaterials can potentially provide additional benefits in drug delivery for disease treatment. Given that this modification determines final therapeutic efficacy of drug carriers, here, we investigate systematically the role of grafting amount of antioxidant gallic acid (GA) onto GN in situ gelling copolymers made of biodegradable gelatin and thermo-responsive poly(N-isopropylacrylamide) for intracameral delivery of pilocarpine in antiglaucoma treatment. As expected, increasing redox reaction time increased total antioxidant activities and free radical scavenging abilities of synthesized carrier biomaterials. The hydrophilic nature of antioxidant molecules strongly affected physicochemical properties of carrier materials with varying GA grafting amounts, thereby dictating in vitro release behaviors and mechanisms of pilocarpine. In vitro oxidative stress challenges revealed that biocompatible carriers with high GA content alleviated lens epithelial cell damage and reduced reactive oxygen species. Intraocular pressure and pupil diameter in glaucomatous rabbits showed correlations with GA-mediated release of pilocarpine. Additionally, enhanced pharmacological treatment effects prevented corneal endothelial cell loss during disease progression. Increasing GA content increased total antioxidant level and decreased nitrite level in the aqueous humor, suggesting a much improved antioxidant status in glaucomatous eyes. This work significantly highlights the dependence of physicochemical properties, drug release behaviors, and bioactivities on intrinsic antioxidant capacities of therapeutic carrier biomaterials for glaucoma treatment. Development of injectable biodegradable polymer depots and functionalization of carrier biomaterials with antioxidant can potentially provide benefits such as improved bioavailability, controlled release pattern, and increased therapeutic effect in intracameral pilocarpine administration for glaucoma

Enhanced functional properties of tannic acid after thermal hydrolysis

Science.gov (United States)

Thermal hydrolysis processing of fresh tannic acid was carried out in a closed reactor at four different temperatures (65, 100, 150 and 200°C). Pressures reached in the system were 1.3 and 4.8 MPa at 150 and 200°C, respectively. Hydrolysis products (gallic acid and pyrogallol) were separated and qua...

Synthesis of ellagic acid and its 4,4'-di-Ο-alky derivatives from gallic acid

OpenAIRE

Alam, Ashraful; 高口, 豊; 坪井, 貞夫

2005-01-01

Synthesis of ellagic acid and its 4,4'-di-Ο-alkyl derivatives from gallic acid is described. Ellagic acid is prepared by oxidative coupling of gallic acid with ο-chloranil. Functionalized methyl bormogallate underwent Ullmann coupling to give the biphenyl that upon lactonization resulted in the ellagic acid and its alkoxy derivatives.

The Effect of Marine Derived n-3 Fatty Acids on Adipose Tissue Metabolism and Function

Directory of Open Access Journals (Sweden)

Marijana Todorčević

2015-12-01

Full Text Available Adipose tissue function is key determinant of metabolic health, with specific nutrients being suggested to play a role in tissue metabolism. One such group of nutrients are the n-3 fatty acids, specifically eicosapentaenoic acid (EPA; 20:5n-3 and docosahexaenoic acid (DHA; 22:6n-3. Results from studies where human, animal and cellular models have been utilised to investigate the effects of EPA and/or DHA on white adipose tissue/adipocytes suggest anti-obesity and anti-inflammatory effects. We review here evidence for these effects, specifically focusing on studies that provide some insight into metabolic pathways or processes. Of note, limited work has been undertaken investigating the effects of EPA and DHA on white adipose tissue in humans whilst more work has been undertaken using animal and cellular models. Taken together it would appear that EPA and DHA have a positive effect on lowering lipogenesis, increasing lipolysis and decreasing inflammation, all of which would be beneficial for adipose tissue biology. What remains to be elucidated is the duration and dose required to see a favourable effect of EPA and DHA in vivo in humans, across a range of adiposity.

Adsorption and oxidation of oxalic acid on anatase TiO2 (001) surface: A density functional theory study.

Science.gov (United States)

Sun, Tao; Wang, Yun; Zhang, Haimin; Liu, Porun; Zhao, Huijun

2015-09-15

Anatase TiO2 (001) surfaces have attracted great interest for photo-degradation of organic species recently due to their high reactivity. In this work, adsorption properties and oxidation mechanisms of oxalic acid on the anatase TiO2 (001) surface have been theoretically investigated using the first-principles density functional theory. Various possible adsorption configurations are considered by diversifying the connectivity of carboxylic groups with the surface. It is found that the adsorption of oxalic acid on the anatase (001) surface prefer the dissociative states. A novel double-bidentate configuration has been found due to the structural match between oxalic acid and the (001) surface. More charge is transferred from the adsorbed oxalic acid to the surface with the double-bidentate configuration when comparing with other adsorption structures. Thus, there is a positive correlation relationship between the transferred charge amount and the interfacial bond numbers when oxalic acid adsorbs on the anatase TiO2 (001) surface. The adsorption energies with dispersion corrections have demonstrated that the van der Waals interactions play an important role in the adsorption, especially when adsorbates are close to the surface. Copyright © 2015 Elsevier Inc. All rights reserved.

Association of serum uric acid level with muscle strength and cognitive function among Chinese aged 50-74 years

DEFF Research Database (Denmark)

Wu, Yili; Zhang, Dongfeng; Pang, Zengchang

2013-01-01

AIM: Previous studies have shown that uric acid (UA) has strong anti-oxidant properties, and that high circulating levels of UA are prospectively associated with improved muscle function and cognitive performances in elderly Caucasians. We carried out a replication study in elderly Chinese using...

Boronic acid functionalized silica microparticles for isolation of flavonoids from Hypericum perforatum

Directory of Open Access Journals (Sweden)

Onur Çetinkaya

2017-10-01

Full Text Available We have selectively separated cis- and/or vicinal-diol-containing flavonoids from Hypericum perfaratum (HP by adsorption/desorption using aminophenylboronic acid (APBA functionalized uniform (1.6 μm silica microparticles (BASPs synthesized via the Stöber method. Silica particles were alkylated by its terminal –OH with 3-aminopropyl trimethoxysilane (APTS, glutaraldehyde (GA and APBA. The results from model adsorption studies indicated that these microparticles selectively adsorbed quercetin and rutin but partially apigenin. The antioxidant and antiradical activities of the desorption solution were slightly higher than that of the post-adsorption solution. These results indicated that the BASP selectively adsorbed the cis- and/or vicinal antioxidant and antiradical flavonoids.

Ion binding by humic and fulvic acids: A computational procedure based on functional site heterogeneity and the physical chemistry of polyelectrolyte solutions

International Nuclear Information System (INIS)

Marinsky, J.A.; Reddy, M.M.; Ephraim, J.; Mathuthu, A.

1988-04-01

Ion binding equilibria for humic and fulvic acids are examined from the point of view of functional site heterogeneity and the physical chemistry of polyelectrolyte solutions. A detailed explanation of the potentiometric properties of synthetic polyelectrolytes and ion-exchange gels is presented first to provide the basis for a parallel consideration of the potentiometric properties exhibited by humic and fulvic acids. The treatment is then extended to account for functional site heterogeneity. Sample results are presented for analysis of the ion-binding reactions of a standard soil fulvic acid (Armadale Horizons Bh) with this approach to test its capability for anticipation of metal ion removal from solution. The ultimate refined model is shown to be adaptable, after appropriate consideration of the heterogeneity and polyelectrolyte factors, to programming already available for the consideration of ion binding by inorganics in natural waters. (orig.)

Ocular biocompatibility of gelatin microcarriers functionalized with oxidized hyaluronic acid

Energy Technology Data Exchange (ETDEWEB)

Lai, Jui-Yang, E-mail: jylai@mail.cgu.edu.tw [Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan 33302, Taiwan (China); Biomedical Engineering Research Center, Chang Gung University, Taoyuan 33302, Taiwan (China); Center for Tissue Engineering, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan (China); Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan (China); Department of Materials Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan (China); Ma, David Hui-Kang [Center for Tissue Engineering, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan (China); Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan (China); Department of Chinese Medicine, Chang Gung University, Taoyuan 33302, Taiwan (China)

2017-03-01

Given that the presence of aldehyde groups on the oxidized sugar residues may pose toxicity concerns, it is necessary to examine the safety of gelatin microcarriers (GMC) functionalized with oxidized hyaluronic acid (oHA) for potential ophthalmic applications. In this study, the ocular biocompatibility of biopolymer microcarriers was investigated in vitro using primary rabbit corneal cell cultures and in vivo using the anterior chamber of the rabbit eye model. Our results showed that different types of corneal cells including epithelial, stromal, and endothelial cells remain viable and actively proliferate following 2 and 4 days of exposure to test materials. In addition, similar interleukin-6 gene expression levels and comet tail lengths were seen in the presence and absence of biopolymer microcarriers, suggesting no cellular inflammation and genotoxicity. After 7 and 14 days of intracameral injection in the rabbit eyes, both the GMC samples and their counterparts functionalized with oHA were well tolerated in the ocular anterior chamber as demonstrated by slit-lamp biomicroscopy. Clinical observations including specular microscopic examinations, corneal topography, and corneal thickness measurements also showed that the rabbits bearing biopolymer microcarriers exhibit no signs of corneal edema and astigmatism as well as endothelial damage, indicating the absence of tissue response. It is concluded that the GMC materials functionalized with oHA (oxidation level: 10.4 ± 0.9%) are compatible toward corneal cells and ocular anterior segment tissues at a concentration of 10 mg/ml. The information about the effect of coupling of aldehyde-functionalized HA to gelatin on in vitro and in vivo biocompatibility of biopolymer composites can be used as further development of corneal stromal cell microcarriers for tissue engineering applications. - Highlights: • We examine in vitro and in vivo ocular biocompatibility of biopolymer microcarrier. • Gelatin-oxidized HA

Ocular biocompatibility of gelatin microcarriers functionalized with oxidized hyaluronic acid

International Nuclear Information System (INIS)

Lai, Jui-Yang; Ma, David Hui-Kang

2017-01-01

Given that the presence of aldehyde groups on the oxidized sugar residues may pose toxicity concerns, it is necessary to examine the safety of gelatin microcarriers (GMC) functionalized with oxidized hyaluronic acid (oHA) for potential ophthalmic applications. In this study, the ocular biocompatibility of biopolymer microcarriers was investigated in vitro using primary rabbit corneal cell cultures and in vivo using the anterior chamber of the rabbit eye model. Our results showed that different types of corneal cells including epithelial, stromal, and endothelial cells remain viable and actively proliferate following 2 and 4 days of exposure to test materials. In addition, similar interleukin-6 gene expression levels and comet tail lengths were seen in the presence and absence of biopolymer microcarriers, suggesting no cellular inflammation and genotoxicity. After 7 and 14 days of intracameral injection in the rabbit eyes, both the GMC samples and their counterparts functionalized with oHA were well tolerated in the ocular anterior chamber as demonstrated by slit-lamp biomicroscopy. Clinical observations including specular microscopic examinations, corneal topography, and corneal thickness measurements also showed that the rabbits bearing biopolymer microcarriers exhibit no signs of corneal edema and astigmatism as well as endothelial damage, indicating the absence of tissue response. It is concluded that the GMC materials functionalized with oHA (oxidation level: 10.4 ± 0.9%) are compatible toward corneal cells and ocular anterior segment tissues at a concentration of 10 mg/ml. The information about the effect of coupling of aldehyde-functionalized HA to gelatin on in vitro and in vivo biocompatibility of biopolymer composites can be used as further development of corneal stromal cell microcarriers for tissue engineering applications. - Highlights: • We examine in vitro and in vivo ocular biocompatibility of biopolymer microcarrier. • Gelatin-oxidized HA

Mechanistic Investigation of Molybdate-Catalysed Transfer Hydrodeoxygenation

DEFF Research Database (Denmark)

Larsen, Daniel Bo; Petersen, Allan Robertson; Dethlefsen, Johannes Rytter

2016-01-01

The molybdate-catalysed transfer hydrodeoxygenation (HDO) of benzyl alcohol to toluene driven by oxidation of the solvent isopropyl alcohol to acetone has been investigated by using a combination of experimental and computational methods. A Hammett study that compared the relative rates for the t......The molybdate-catalysed transfer hydrodeoxygenation (HDO) of benzyl alcohol to toluene driven by oxidation of the solvent isopropyl alcohol to acetone has been investigated by using a combination of experimental and computational methods. A Hammett study that compared the relative rates...

Does docosahexaenoic acid supplementation in term infants enhance neurocognitive functioning in infancy?

Science.gov (United States)

Heaton, Alexandra E; Meldrum, Suzanne J; Foster, Jonathan K; Prescott, Susan L; Simmer, Karen

2013-11-20

The proposal that dietary docosahexaenoic acid (DHA) enhances neurocognitive functioning in term infants is controversial. Theoretical evidence, laboratory research and human epidemiological studies have convincingly demonstrated that DHA deficiency can negatively impact neurocognitive development. However, the results from randomized controlled trials (RCTs) of DHA supplementation in human term-born infants have been inconsistent. This article will (i) discuss the role of DHA in the human diet, (ii) explore the physiological mechanisms by which DHA plausibly influences neurocognitive capacity, and (iii) seek to characterize the optimal intake of DHA during infancy for neurocognitive functioning, based on existing research that has been undertaken in developed countries (specifically, within Australia). The major observational studies and RCTs that have examined dietary DHA in human infants and animals are presented, and we consider suggestions that DHA requirements vary across individuals according to genetic profile. It is important that the current evidence concerning DHA supplementation is carefully evaluated so that appropriate recommendations can be made and future directions of research can be strategically planned.

Does docosahexaenoic acid supplementation in term infants enhance neurocognitive functioning in infancy?

Directory of Open Access Journals (Sweden)

Alexandra Elizabeth Heaton

2013-11-01

Full Text Available The proposal that dietary docosahexaenoic acid (DHA enhances neurocognitive functioning in term infants is controversial. Theoretical evidence, laboratory research and human epidemiological studies have convincingly demonstrated that DHA deficiency can negatively impact neurocognitive development. However, the results from randomized controlled trials (RCTs of DHA supplementation in human term-born infants have been inconsistent. This article will i discuss the role of DHA in the human diet, ii explore the physiological mechanisms by which DHA plausibly influences neurocognitive capacity and iii seek to characterize the optimal intake of DHA during infancy for neurocognitive functioning, based on existing research that has been undertaken in developed countries (specifically, within Australia. The major observational studies and RCTs that have examined dietary DHA in human infants and animals are presented, and we consider suggestions that DHA requirements vary across individuals according to genetic profile. It is important that the current evidence concerning DHA supplementation is carefully evaluated so that appropriate recommendations can be made and future directions of research can be strategically planned.

Synthesis and Characterization of Rhodamine B-ethylenediamine-hyaluronan Acid as Potential Biological Functional Materials

Science.gov (United States)

Li, Y. L.; Wang, W. X.; Wang, Y.; Zhang, W. B.; Gong, H. M.; Liu, M. X.

2018-05-01

The purpose of this study is to synthesize and characterize fluorescent polymers, rhodamine B-ethylenediamine-hyaluronan acid (RhB-EA-HA). RhB-EA-HA was successfully synthesized by ester ammonolysis reaction and amidation reaction. Moreover, the structural properties of RhB-EA-HA were characterized by 1H-NMR spectra, UV-vis spectrometry and Fourier transform infrared spectroscopy (FT-IR). RhB-EA-HA can be grafted on the surface of silica nanomaterials, which may be potential biological functional materials for drug delivery system.

Soft Cysteine Signaling Network: The Functional Significance of Cysteine in Protein Function and the Soft Acids/Bases Thiol Chemistry That Facilitates Cysteine Modification.

Science.gov (United States)

Wible, Ryan S; Sutter, Thomas R

2017-03-20

The unique biophysical and electronic properties of cysteine make this molecule one of the most biologically critical amino acids in the proteome. The defining sulfur atom in cysteine is much larger than the oxygen and nitrogen atoms more commonly found in the other amino acids. As a result of its size, the valence electrons of sulfur are highly polarizable. Unique protein microenvironments favor the polarization of sulfur, thus increasing the overt reactivity of cysteine. Here, we provide a brief overview of the endogenous generation of reactive oxygen and electrophilic species and specific examples of enzymes and transcription factors in which the oxidation or covalent modification of cysteine in those proteins modulates their function. The perspective concludes with a discussion of cysteine chemistry and biophysics, the hard and soft acids and bases model, and the proposal of the Soft Cysteine Signaling Network: a hypothesis proposing the existence of a complex signaling network governed by layered chemical reactivity and cross-talk in which the chemical modification of reactive cysteine in biological networks triggers the reorganization of intracellular biochemistry to mitigate spikes in endogenous or exogenous oxidative or electrophilic stress.

Omega-3 polyunsaturated fatty acids preserve retinal function in type 2 diabetic mice.

Science.gov (United States)

Sapieha, P; Chen, J; Stahl, A; Seaward, M R; Favazza, T L; Juan, A M; Hatton, C J; Joyal, J-S; Krah, N M; Dennison, R J; Tang, J; Kern, T S; Akula, J D; Smith, L E H

2012-07-23

Diabetic retinopathy (DR) is associated with hyperglycemia-driven microvascular pathology and neuronal compromise in the retina. However, DR is also linked to dyslipidemia. As omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) are protective in proliferative retinopathy, we investigated the capacity of ω-3PUFAs to preserve retinal function in a mouse model of type 2 diabetes mellitus (T2DM). Male leptin-receptor-deficient (db/db) mice were maintained for 22 weeks (4 weeks-26 weeks of life) on calorically and compositionally matched diets, except for 2% enrichment in either ω-3 or ω-6PUFAs. Visual function was assessed at 9, 14 and 26 weeks by electroretinography. Retinal capillary and neuronal integrity, as well as glucose challenge responses, were assessed on each diet. The ω-3PUFA diet significantly preserved retinal function in the mouse model of T2DM to levels similar to those observed in nondiabetic control mice on normal chow. Conversely, retinal function gradually deteriorated in db/db mice on a ω-6PUFA-rich diet. There was also an enhanced ability of ω-3PUFA-fed mice to respond to glucose challenge. The protection of visual function appeared to be independent of cytoprotective or anti-inflammatory effects of ω-3PUFAs. This study identifies beneficial effects of dietary ω-3PUFAs on visual function in T2DM. The data are consistent with dyslipidemia negatively impacting retinal function. As ω-3PUFA lipid dietary interventions are readily available, safe and inexpensive, increasing ω-3PUFA intake in diabetic patients may slow the progression of vision loss in T2DM.

Identification and functional characterisation of genes encoding the omega-3 polyunsaturated fatty acid biosynthetic pathway from the coccolithophore Emiliania huxleyi.

Science.gov (United States)

Sayanova, Olga; Haslam, Richard P; Calerón, Monica Venegas; López, Noemi Ruiz; Worthy, Charlotte; Rooks, Paul; Allen, Michael J; Napier, Johnathan A

2011-05-01

The Prymnesiophyceae coccolithophore Emiliania huxleyi is one of the most abundant alga in our oceans and therefore plays a central role in marine foodwebs. E. huxleyi is notable for the synthesis and accumulation of the omega-3 long chain polyunsaturated fatty acid docosahexaenoic acid (DHA; 22:6Δ(4,7,10,13,16,19), n-3) which is accumulated in fish oils and known to have health-beneficial properties to humans, preventing cardiovascular disease and related pathologies. Here we describe the identification and functional characterisation of the five E. huxleyi genes which direct the synthesis of docosahexaenoic acid in this alga. Surprisingly, E. huxleyi does not use the conventional Δ6-pathway, instead using the alternative Δ8-desaturation route which has previously only been observed in a few unrelated microorganisms. Given that E. huxleyi accumulates significant levels of the Δ6-desaturated fatty acid stearidonic acid (18:4Δ(6,9,12,15), n-3), we infer that the biosynthesis of DHA is likely to be metabolically compartmentalised from the synthesis of stearidonic acid. Copyright © 2011 Elsevier Ltd. All rights reserved.

Functionalized ZnO Nanoparticles with Gallic Acid for Antioxidant and Antibacterial Activity against Methicillin-Resistant S. aureus

Directory of Open Access Journals (Sweden)

Joomin Lee

2017-11-01

Full Text Available In this study, we report a new multifunctional nanoparticle with antioxidative and antibacterial activities in vitro. ZnO@GA nanoparticles were fabricated by coordinated covalent bonding of the antioxidant gallic acid (GA on the surface of ZnO nanoparticles. This addition imparts both antioxidant activity and high affinity for the bacterial cell membrane. Antioxidative activities at various concentrations were evaluated using a 2,2′-azino-bis(ethylbenzthiazoline-6-sulfonic acid (ABTS radical scavenging method. Antibacterial activities were evaluated against Gram-positive bacteria (Staphylococcus aureus: S. aureus, including several strains of methicillin-resistant S. aureus (MRSA, and Gram-negative bacteria (Escherichia coli. The functionalized ZnO@GA nanoparticles showed good antioxidative activity (69.71%, and the bactericidal activity of these nanoparticles was also increased compared to that of non-functionalized ZnO nanoparticles, with particularly effective inhibition and high selectivity for MRSA strains. The results indicate that multifunctional ZnO nanoparticles conjugated to GA molecules via a simple surface modification process displaying both antioxidant and antibacterial activity, suggesting a possibility to use it as an antibacterial agent for removing MRSA.

Extraction of unsaturated fatty acid-rich oil from common carp (Cyprinus carpio) roe and production of defatted roe hydrolysates with functional, antioxidant, and antibacterial properties.

Science.gov (United States)

Ghelichi, Sakhi; Shabanpour, Bahareh; Pourashouri, Parastoo; Hajfathalian, Mona; Jacobsen, Charlotte

2018-03-01

Common carp roe is a rich protein and oil source, which is usually discarded with no specific use. The aims of this study were to extract oil from the discarded roe and examine functional, antioxidant, and antibacterial properties of defatted roe hydrolysates (CDRHs) at various degrees of hydrolysis (DH). Gas chromatography of fatty acid methyl esters revealed that common carp roe oil contained high levels of unsaturated fatty acids. The results of high-performance liquid chromatography-mass spectrometry indicated that enzymatic hydrolysis of defatted roe yielded higher content of essential amino acids. CDRHs displayed higher solubility than untreated defatted roe, which increased with DH. Better emulsifying and foaming properties were observed at lower DH and non-isoelectric points. Furthermore, water and oil binding capacity decreased with DH. CDRHs exhibited antioxidant activity both in vitro and in 5% roe oil-in-water emulsions and inhibited the growth of certain bacterial strains. Common carp roe could be a promising source of unsaturated fatty acids and functional bioactive agents. Unsaturated fatty acid-rich oil extracted from common carp roe can be delivered into food systems by roe oil-in-water emulsions fortified by functional, antioxidant, and antibacterial hydrolysates from the defatted roe. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids

DEFF Research Database (Denmark)

Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strømgaard, Kristian

2014-01-01

An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order...

Analysis of organic acids and phenols of interest in the wine industry using Langmuir–Blodgett films based on functionalized nanoparticles

International Nuclear Information System (INIS)

Medina-Plaza, C.; García-Cabezón, C.; García-Hernández, C.; Bramorski, C.; Blanco-Val, Y.; Martín-Pedrosa, F.; Kawai, T.; Saja, J.A. de; Rodríguez-Méndez, M.L.

2015-01-01

Highlights: • For the first time functionalized NPs immobilized in LB films have been used as voltammetric sensors. • Films showed excellent electrocatalytic properties toward phenols and acids found in wines. • Improved performance is due to combination of electrocatalytic NPs with the high surface/volume of LB films. • The potential applications in the wine industry have been evidenced. - Abstract: A chemically modified electrode consisting of Langmuir–Blodgett (LB) films of n-dodecanethiol functionalized gold nanoparticles (S DOD AuNP-LB), was investigated as a voltammetric sensor of organic and phenolic acids of interest in the wine industry. The nanostructured films demonstrated interfacial properties being able to detect the main organic acids present in grapes and wines (tartaric, malic, lactic and citric). Compared to a bare ITO electrode, the modified electrodes exhibited a shift of the reduction potential in the less positive direction and a marked enhancement in the current response. Moreover, the increased electrocatalytic properties made it possible to distinguish between the different dissociable protons of polyprotic acids. The S DOD AuNP-LB sensor was also able to provide enhanced responses toward aqueous solutions of phenolic acids commonly found in wines (caffeic and gallic acids). The presence of nanoparticles increased drastically the sensitivity toward organic acids and phenolic compounds. Limits of detection as low as 10 −6 mol L −1 were achieved. Efficient catalytic activity was also observed in mixtures of phenolic acid/tartaric in the range of pHs typically found in wines. In such mixtures, the electrode was able to provide simultaneous information about the acid and the phenol concentrations with a complete absence of interferences. The excellent sensing properties shown by these sensors could be attributed to the electrocatalytic properties of the nanoparticles combined with the high surface to volume ratio and homogeneity

Analysis of organic acids and phenols of interest in the wine industry using Langmuir–Blodgett films based on functionalized nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Medina-Plaza, C. [Department of Inorganic Chemistry, Engineers School, Universidad de Valladolid (Spain); García-Cabezón, C. [Department of Materials Science, Engineers School, Universidad de Valladolid (Spain); García-Hernández, C.; Bramorski, C. [Department of Inorganic Chemistry, Engineers School, Universidad de Valladolid (Spain); Blanco-Val, Y.; Martín-Pedrosa, F. [Department of Materials Science, Engineers School, Universidad de Valladolid (Spain); Kawai, T. [Department of Industrial Chemistry, Tokyo University of Science (Japan); Saja, J.A. de [Department of Condensed Matter Physics, Universidad de Valladolid (Spain); Rodríguez-Méndez, M.L., E-mail: mluz@eii.uva.es [Department of Inorganic Chemistry, Engineers School, Universidad de Valladolid (Spain)

2015-01-01

Highlights: • For the first time functionalized NPs immobilized in LB films have been used as voltammetric sensors. • Films showed excellent electrocatalytic properties toward phenols and acids found in wines. • Improved performance is due to combination of electrocatalytic NPs with the high surface/volume of LB films. • The potential applications in the wine industry have been evidenced. - Abstract: A chemically modified electrode consisting of Langmuir–Blodgett (LB) films of n-dodecanethiol functionalized gold nanoparticles (S{sub DOD}AuNP-LB), was investigated as a voltammetric sensor of organic and phenolic acids of interest in the wine industry. The nanostructured films demonstrated interfacial properties being able to detect the main organic acids present in grapes and wines (tartaric, malic, lactic and citric). Compared to a bare ITO electrode, the modified electrodes exhibited a shift of the reduction potential in the less positive direction and a marked enhancement in the current response. Moreover, the increased electrocatalytic properties made it possible to distinguish between the different dissociable protons of polyprotic acids. The S{sub DOD}AuNP-LB sensor was also able to provide enhanced responses toward aqueous solutions of phenolic acids commonly found in wines (caffeic and gallic acids). The presence of nanoparticles increased drastically the sensitivity toward organic acids and phenolic compounds. Limits of detection as low as 10{sup −6} mol L{sup −1} were achieved. Efficient catalytic activity was also observed in mixtures of phenolic acid/tartaric in the range of pHs typically found in wines. In such mixtures, the electrode was able to provide simultaneous information about the acid and the phenol concentrations with a complete absence of interferences. The excellent sensing properties shown by these sensors could be attributed to the electrocatalytic properties of the nanoparticles combined with the high surface to volume ratio

Surface-functionalized polymethacrylic acid based hydrogel microparticles for oral drug delivery.

Science.gov (United States)

Sajeesh, S; Bouchemal, K; Sharma, C P; Vauthier, C

2010-02-01

Aim of the present work was to develop novel thiol-functionalized hydrogel microparticles based on poly(methacrylic acid)-chitosan-poly(ethylene glycol) (PCP) for oral drug delivery applications. PCP microparticles were prepared by a modified ionic gelation process in aqueous medium. Thiol modification of surface carboxylic acid groups of PCP micro particles was carried out by coupling l-cysteine with a water-soluble carbodiimide. Ellman's method was adopted to quantify the sulfhydryl groups, and dynamic light-scattering technique was used to measure the average particle size. Cytotoxicity of the modified particles was evaluated on Caco 2 cells by MTT assay. Effect of thiol modification on permeability of paracellular marker fluorescence dextran (FD4) was evaluated on Caco 2 cell monolayers and freshly excised rat intestinal tissue with an Ussing chamber set-up. Mucoadhesion experiments were carried out by an ex vivo bioadhesion method with excised rat intestinal tissue. The average size of the PCP microparticles was increased after thiol modification. Thiolated microparticles significantly improved the paracellular permeability of FD4 across Caco 2 cell monolayers, with no sign of toxicity. However, the efficacy of thiolated system remained low when permeation experiments were carried out across excised intestinal membrane. This was attributed to the high adhesion of the thiolated particles on the gut mucosa. Nevertheless, it can be concluded that surface thiolation is an interesting strategy to improve paracellular permeability of hydrophilic macromolecules. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Adherence of amino acids functionalized iron oxide nanoparticles on bacterial models E. Coli and B. subtilis

Science.gov (United States)

Trujillo, W.; Zarria, J.; Pino, J.; Menacho, L.; Coca, M.; Bustamante, A.

2018-03-01

Magnetic iron oxides nanoparticles (NPs) functionalized with lysine (Lys) and arginine (Arg) was obtained by following chemical co-precipitation route in basic medium. The synthesis was performed by mixing ferrous chloride (FeCl2•4H2O), ferric chloride (FeCl3•6H2O) and the specific amino acid in a molar ratio of 1: 2: 0.5, respectively. High pH sample was washed several times with distilled water to reach a pH similar to distilled water (Ph=7) after the synthesis process, part of the NPs obtained was dried. Of the measurements of XRD and MS was obtained that the samples are magnetic nanoparticles of maghemite of about 9 nm in diameter. Of the FTIR and zeta potential measures was obtained that the amino acids Lys and Arg were correctly functionalized at magnetic nanoparticles, referred to herein as M@Lys and M@Arg. In order to demonstrate the capture and adhesion of the nanoparticles to the bacteria, scanning electron microscopy (SEM) was performed. The obtained visualization of both bacteria shows that they are coated by the magnetic particles. In addition, M@Lys (B. sutilis) were cultured to verify the inhibition of growth measured by colony forming units (CFU), the concentrations of M@Lys were 1.75x102 g/mL and 0.875x102 g/mL. After the confrontation obtained efficiencies of 75.63% and 98.75% respectively for the third dilution. While for the fourth dilution were 90% and 98.57% respectively were obtained for each concentration of nanoparticles. Hinting that a high efficiency of bacterial capture at very low concentrations of NPs, which gives us a tool to capture nanobiotechnology bacteria in liquid cultures with application to capture them in wastewater. Based on our results we concluded that NPS functionalized with the amino acids Lys and Arg adhere to the bacteria efficiently in low concentrations.

Improvement of Intestinal Immune Cell Function by Lactic Acid Bacteria for Dairy Products

Directory of Open Access Journals (Sweden)

Tomonori Kamiya

2016-12-01

Full Text Available Lactic acid bacteria (LAB form a major component of gut microbiota and are often used as probiotics for fermented foods, such as yoghurt. In this study, we aimed to evaluate immunomodulatory activity of LAB, especially that of Lactobacillus bulgaricus ME-552 (ME552 and Streptococcus thermophilus ME-553 (ME553. In vivo/in vitro assay was performed in order to investigate their effects on T cell function. After oral administration of ME553 to C57BL/6 mice, the amount of both interferon γ (IFN-γ and interleukin 17 (IL-17 produced by cluster of differentiation (CD 4+ T cells from Peyer’s patches (PPs were significantly enhanced. On the other hand, ME552 only up-regulated the production of IL-17 from PP cells. The extent of induction for IFN-γ production differed between ME552 and ME553. These results suggest that LAB modulate T cell effector functions and mucosal immunity.

Improvement of Intestinal Immune Cell Function by Lactic Acid Bacteria for Dairy Products.

Science.gov (United States)

Kamiya, Tomonori; Watanabe, Yohei; Makino, Seiya; Kano, Hiroshi; Tsuji, Noriko M

2016-12-23

Lactic acid bacteria (LAB) form a major component of gut microbiota and are often used as probiotics for fermented foods, such as yoghurt. In this study, we aimed to evaluate immunomodulatory activity of LAB, especially that of Lactobacillus bulgaricus ME-552 (ME552) and Streptococcus thermophilus ME-553 (ME553). In vivo/in vitro assay was performed in order to investigate their effects on T cell function. After oral administration of ME553 to C57BL/6 mice, the amount of both interferon γ (IFN-γ) and interleukin 17 (IL-17) produced by cluster of differentiation (CD) 4⁺ T cells from Peyer's patches (PPs) were significantly enhanced. On the other hand, ME552 only up-regulated the production of IL-17 from PP cells. The extent of induction for IFN-γ production differed between ME552 and ME553. These results suggest that LAB modulate T cell effector functions and mucosal immunity.

[The isozymes of stearil-coenzymeA-desaturase and insulin activity in the light of phylogenetic theory of pathology. Oleic fatty acid and realization of biologic functions of trophology and locomotion].

Science.gov (United States)

2013-11-01

The formation of function of isozymes of stearil-coenzymeA-desaturases occured at the different stages of phylogeny under realization of biologic function of trophology (stearil-coenzymeA-desaturase 1) and biologic function of locomotion, insulin system (stearil-coenzymeA-desaturase 2) billions years later. The stearil-coenzymeA-desaturase 1 transforms in C 18:1 oleic fatty acid only exogenous C 16:0 palmitinic saturated fatty acid. The stearil-coenzymeA-desaturase 2 transforms only endogenic palmitinic saturated fatty acid, synthesized form glucose. The biologic role of insulin is in energy support of biologic function of locomotion. Insulin through expressing stearil-coenzymeA-desaturase 2 transforms energetically non-optimal palmitinic variation of metabolism of substrates into highly effective oleic variation for cells' groundwork of energy (saturated fatty acid and mono fatty acid). The surplus of palmitinic saturated fatty acid in food is enabled in pathogenesis of resistance to insulin and derangement of synthesis of hormone by beta-cells of islets. The resistance to insulin and diabetes mellitus are primarily the derangement of metabolism of saturated fatty acids with mono fatty acids, energy problems of organism and only afterwards the derangement of metabolism of carbohydrates. It is desirable to restrict food intake of exogenous palmitinic saturated fatty acid. The reasons are low expression of independent of insulin stearil-coenzymeA-desaturase 2, marked lipotoxicity of polar form of palmitinic saturated fatty acid and synthesis of non-optimal palmitinic triglycerides instead of physiologic and more energetically more effective oleic triglycerides.

Acidity function p(a(H) gamma(Cl)) as a step to pH assessment.

Science.gov (United States)

Camões, Maria Filomena; Guiomar Lito, Maria

2002-11-01

The conventional assignment of pH reference buffer standards, pH(S), is achieved by means of a series of procedures that follow from measurement of Harned cell potentials for an electrolyte solution which is the buffer solution of interest. An intermediate step is assessment of the acidity function p( a(H) gamma(Cl))(0), the extrapolated value of a linear representation of the dependence of p( a(H) gamma(Cl)) on m(Cl) for at least three different molalities, m(Cl), of added alkali chloride (0.005; 0.010; 0.015 mol kg(-1) KCl). This experimental value can be compared with a theoretically expected value calculated from the dissociation constants of the buffer species. Whereas these calculations always give negative slopes for diprotic and triprotic acids and zero slope for monoprotic acids, experimental values with negative or positive slopes can be obtained for well fitting straight lines obtained for buffer solutions with ionic strengths from 0.0025 to 0.144 mol kg(-1). Such disagreement between theoretically and experimentally obtained values introduce an extra source of uncertainty in the establishment of pH(S) and on its traceability chain. In this work examples are presented and discussed for which the discrepancy between expected and experimental values leads to different intercept p( a(H) gamma(Cl))(0).

Molecular Features of Humic Acids and Fulvic Acids from Contrasting Environments

NARCIS (Netherlands)

Schellekens, Judith; Buurman, Peter; Kalbitz, Karsten; Zomeren, van Andre; Vidal-Torrado, Pablo; Cerli, Chiara; Comans, Rob N.J.

2017-01-01

Insight in the molecular structure of humic acid (HA) and fulvic acid (FA) can contribute to identify relationships between their molecular properties, and further our quantitative abilities to model important organic matter functions such as metal complexation and association with mineral

Exploitation of grape marc as functional substrate for lactic acid bacteria and bifidobacteria growth and enhanced antioxidant activity.

Science.gov (United States)

Campanella, Daniela; Rizzello, Carlo Giuseppe; Fasciano, Cristina; Gambacorta, Giuseppe; Pinto, Daniela; Marzani, Barbara; Scarano, Nicola; De Angelis, Maria; Gobbetti, Marco

2017-08-01

This study aimed at using grape marc for the growth of lactic acid bacteria and bifidobacteria with the perspective of producing a functional ingredient having antioxidant activity. Lactobacillus plantarum 12A and PU1, Lactobacillus paracasei 14A, and Bifidobacterium breve 15A showed the ability to grow on grape marc (GM) based media. The highest bacterial cell density (>9.0 CFU/g) was found in GM added of 1% of glucose (GMG). Compared to un-inoculated and incubated control fermented GMG showed a decrease of carbohydrates and citric acid together with an increase of lactic acid. The content of several free amino acids and phenol compounds differed between samples. Based on the survival under simulated gastro-intestinal conditions, GMG was a suitable carrier of lactic acid bacteria and bifidobacteria strains. Compared to the control, cell-free supernatant (CFS) of fermented GMG exhibited a marked antioxidant activity in vitro. The increased antioxidant activity was confirmed using Caco-2 cell line after inducing oxidative stress, and determining cell viability and radical scavenging activity through MTT and DCFH-DA assays, respectively. Supporting these founding, the SOD-2 gene expression of Caco-2 cells also showed a lowest pro-oxidant effect induced by the four CFS of GMG fermented by lactic acid bacteria and bifidobacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

Requirement of a Functional Flavin Mononucleotide Prenyltransferase for the Activity of a Bacterial Decarboxylase in a Heterologous Muconic Acid Pathway in Saccharomyces cerevisiae.

Science.gov (United States)

Weber, Heike E; Gottardi, Manuela; Brückner, Christine; Oreb, Mislav; Boles, Eckhard; Tripp, Joanna

2017-05-15

Biotechnological production of cis , cis -muconic acid from renewable feedstocks is an environmentally sustainable alternative to conventional, petroleum-based methods. Even though a heterologous production pathway for cis , cis -muconic acid has already been established in the host organism Saccharomyces cerevisiae , the generation of industrially relevant amounts of cis , cis -muconic acid is hampered by the low activity of the bacterial protocatechuic acid (PCA) decarboxylase AroY isomeric subunit C iso (AroY-C iso ), leading to secretion of large amounts of the intermediate PCA into the medium. In the present study, we show that the activity of AroY-C iso in S. cerevisiae strongly depends on the strain background. We could demonstrate that the strain dependency is caused by the presence or absence of an intact genomic copy of PAD1 , which encodes a mitochondrial enzyme responsible for the biosynthesis of a prenylated form of the cofactor flavin mononucleotide (prFMN). The inactivity of AroY-C iso in strain CEN.PK2-1 could be overcome by plasmid-borne expression of Pad1 or its bacterial homologue AroY subunit B (AroY-B). Our data reveal that the two enzymes perform the same function in decarboxylation of PCA by AroY-C iso , although coexpression of Pad1 led to higher decarboxylase activity. Conversely, AroY-B can replace Pad1 in its function in decarboxylation of phenylacrylic acids by ferulic acid decarboxylase Fdc1. Targeting of the majority of AroY-B to mitochondria by fusion to a heterologous mitochondrial targeting signal did not improve decarboxylase activity of AroY-C iso , suggesting that mitochondrial localization has no major impact on cofactor biosynthesis. IMPORTANCE In Saccharomyces cerevisiae , the decarboxylation of protocatechuic acid (PCA) to catechol is the bottleneck reaction in the heterologous biosynthetic pathway for production of cis , cis -muconic acid, a valuable precursor for the production of bulk chemicals. In our work, we demonstrate

Short-term increase of plasma free fatty acids does not interfere with intrinsic mitochondrial function in healthy young men

NARCIS (Netherlands)

Brands, Myrte; Hoeks, Joris; Sauerwein, Hans P.; Ackermans, Mariette T.; Ouwens, Margriet; Lammers, Nicolette M.; van der Plas, Mart N.; Schrauwen, Patrick; Groen, Albert K.; Serlie, Mireille J.

2011-01-01

Free fatty acid (FFA)- and obesity-induced insulin resistance has been associated with disturbed mitochondrial function. Elevated plasma FFA can impair insulin-induced increase of adenosine triphosphate synthesis and downregulate the expression of genes important in the biogenesis of mitochondria in

Fatty acid-producing hosts

Science.gov (United States)

Pfleger, Brian F; Lennen, Rebecca M

2013-12-31

Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

[Role of sialic acid loss in the myocardium in depressing the contractile function of the heart muscle during stress].

Science.gov (United States)

Meerson, F Z; Saulia, A I; Gudumak, V S

1985-01-01

Under conditions of stress a time-dependent decrease in content of sialic acids was found in adult rats; within 9 hrs of the animal immobilization the sialic acid content was decreased by 40% as compared with controls. At the same time, activities of trypsin and LDHI were increased in blood serum. The data obtained suggest that activation of proteases occurring during the stress led to increased hydrolysis of base components of glycocalyx and to impairment of the cardiomyocyte sarcolemma. These phenomena appear to be responsible for the post-stress deterioration of heart muscle contractile functions.

Binary boronic acid-functionalized attapulgite with high adsorption capacity for selective capture of nucleosides at acidic pH values

International Nuclear Information System (INIS)

Li, Huihui; Zhu, Shuqiang; Cheng, Ting; Wang, Shuxia; Zhu, Bin; Liu, Xiaoyan; Zhang, Haixia

2016-01-01

Boronate affinity materials have been widely used for selective capture of cis-diols such as nucleosides. Adsorbents with features of low binding pH and high adsorption capacity are highly desired. However, most reported materials only possess one of the two features. We have synthesized a 1,3,5-triazine-containing binary boronic acid by reacting cyanuric chloride with 3-amino phenylboronic acid, and the product was then grafted onto attapulgite (a fibrous aluminum-magnesium silicate). The resulting functionalized attapulgite exhibit low binding pH (5.0) and display high adsorption capacity (19.5 ± 1.1 mg⋅g"−"1 for adenosine). The material exhibits high selectivity for cis-diols even in the presence of a 1000-fold excess of interferences. It was applied to the selective extraction of nucleosides from human urine. Typical features of the method include (a) limits of detection in the range from 4 to 17 ng⋅mL"−"1, (b) limits of quantification between 13 and 57 ng⋅mL"−"1, (c) relative standard deviations of ≤9.1 %, and (d) recoveries of nucleosides from spiked human urine between 85.0 and 112.9 %. In our perception, the material and method offer a promising strategy for selective capture of cis-diols in the areas of proteomics, metabolomics and glycomics. (author)

Nanoparticle-functionalized nucleic acids: A strategy for amplified electrochemical detection of some single-base mismatches

International Nuclear Information System (INIS)

Ahangar, Laleh Enayati; Mehrgardi, Masoud A.

2011-01-01

In this study, nanoparticle-functionalized nucleic acids were employed to improve the sensitivity of electrochemical DNA biosensors that make capable them to detect different types of single-base mismatches (SBMs), including thermodynamically stable ones. The present biosensor was constructed by the immobilization of platinum nanoparticles (Pt-NPs) on the surface of a carbon paste electrode (CPE) via SH-functionalized DNA. A redox probe of 2-mercapto-1-methyl imidazole (MMI), which has different electrochemical behavior on Pt-NP and CPE, was used. This behavior helps to overcome the pinhole effect in DNA hybridization biosensors. Additionally, in the present biosensor, the positioning of the redox probe under the SBM in DNA, which decreases the sensitivity of most DNA biosensors, did not contribute to the observed electrochemical signal.

Nanoparticle-functionalized nucleic acids: A strategy for amplified electrochemical detection of some single-base mismatches

Energy Technology Data Exchange (ETDEWEB)

Ahangar, Laleh Enayati [Department of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Mehrgardi, Masoud A., E-mail: m.mehrgardi@gmail.co [Department of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

2011-02-15

In this study, nanoparticle-functionalized nucleic acids were employed to improve the sensitivity of electrochemical DNA biosensors that make capable them to detect different types of single-base mismatches (SBMs), including thermodynamically stable ones. The present biosensor was constructed by the immobilization of platinum nanoparticles (Pt-NPs) on the surface of a carbon paste electrode (CPE) via SH-functionalized DNA. A redox probe of 2-mercapto-1-methyl imidazole (MMI), which has different electrochemical behavior on Pt-NP and CPE, was used. This behavior helps to overcome the pinhole effect in DNA hybridization biosensors. Additionally, in the present biosensor, the positioning of the redox probe under the SBM in DNA, which decreases the sensitivity of most DNA biosensors, did not contribute to the observed electrochemical signal.

Optimizing biosensing properties on undecylenic Acid-functionalized diamond.

Science.gov (United States)

Zhong, Yu Lin; Chong, Kwok Feng; May, Paul W; Chen, Zhi-Kuan; Loh, Kian Ping

2007-05-08

The optimization of biosensing efficiency on a diamond platform depends on the successful coupling of biomolecules on the surface, and also on effective signal transduction in the biorecognition events. In terms of biofunctionalization of diamond surfaces, surface electrochemical studies of diamond modified with undecylenic acid (UA), with and without headgroup protection, were performed. The direct photochemical coupling method employing UA was found to impart a higher density of carboxylic acid groups on the diamond surface compared to that using trifluoroethyl undecenoate (TFEU) as the protecting group during the coupling process. Non-faradic impedimetric DNA sensing revealed that lightly doped diamond gives better signal transduction sensitivity compared to highly doped diamond.

The impact of serum uric acid reduction on renal function and blood pressure in chronic kidney disease patients with hyperuricemia.

Science.gov (United States)

Tsuji, Takayuki; Ohishi, Kazuhisa; Takeda, Asumi; Goto, Daiki; Sato, Taichi; Ohashi, Naro; Fujigaki, Yoshihide; Kato, Akihiko; Yasuda, Hideo

2018-04-26

Febuxostat is tolerable in chronic kidney disease (CKD) patients with hyperuricemia. However, the long-term effect of lowering uric acid with febuxostat on renal function and blood pressure has not been elucidated. This was a 2 years retrospective observational study. 86 CKD patients with hyperuricemia who continued with allopurinol (allopurinol group, n = 30), switched from allopurinol to febuxostat (switched group, n = 25), or were newly prescribed febuxostat (febuxostat group, n = 31) were included in this study. Serum uric acid, estimated glomerular filtration rate (eGFR), blood pressure, and urinary protein were analyzed. Moreover, the impact of serum uric acid reduction on renal function and blood pressure was assessed. Serum uric acid in the switched and febuxostat groups was significantly reduced at 6 months (switched group; 8.49 ± 1.32-7.19 ± 1.14 mg/dL, p uric acid was increased (6.86 ± 0.87-7.10 ± 0.85 mg/dL, p = 0.0213). eGFR was significantly increased (35.2 ± 12.8-37.3 ± 13.9 mL/min/1.73 m 2 , p = 0.0232), while mean arterial pressure (93.1 ± 10.8-88.2 ± 9.5 mmHg, p = 0.0039) was significantly decreased at 6 months in the febuxostat group, resulting in the retention of eGFR for 2 years. The impact of serum uric acid reduction might have beneficial effects on CKD progression and blood pressure. However, a large prospective study is needed to determine the long-term efficacy of febuxostat therapy in CKD patients with hyperuricemia.

Bile acids modulate signaling by functional perturbation of plasma membrane domains.

Science.gov (United States)

Zhou, Yong; Maxwell, Kelsey N; Sezgin, Erdinc; Lu, Maryia; Liang, Hong; Hancock, John F; Dial, Elizabeth J; Lichtenberger, Lenard M; Levental, Ilya

2013-12-13

Eukaryotic cell membranes are organized into functional lipid and protein domains, the most widely studied being membrane rafts. Although rafts have been associated with numerous plasma membrane functions, the mechanisms by which these domains themselves are regulated remain undefined. Bile acids (BAs), whose primary function is the solubilization of dietary lipids for digestion and absorption, can affect cells by interacting directly with membranes. To investigate whether these interactions affected domain organization in biological membranes, we assayed the effects of BAs on biomimetic synthetic liposomes, isolated plasma membranes, and live cells. At cytotoxic concentrations, BAs dissolved synthetic and cell-derived membranes and disrupted live cell plasma membranes, implicating plasma membrane damage as the mechanism for BA cellular toxicity. At subtoxic concentrations, BAs dramatically stabilized domain separation in Giant Plasma Membrane Vesicles without affecting protein partitioning between coexisting domains. Domain stabilization was the result of BA binding to and disordering the nonraft domain, thus promoting separation by enhancing domain immiscibility. Consistent with the physical changes observed in synthetic and isolated biological membranes, BAs reorganized intact cell membranes, as evaluated by the spatial distribution of membrane-anchored Ras isoforms. Nanoclustering of K-Ras, related to nonraft membrane domains, was enhanced in intact plasma membranes, whereas the organization of H-Ras was unaffected. BA-induced changes in Ras lateral segregation potentiated EGF-induced signaling through MAPK, confirming the ability of BAs to influence cell signal transduction by altering the physical properties of the plasma membrane. These observations suggest general, membrane-mediated mechanisms by which biological amphiphiles can produce their cellular effects.

Effects of Acids, Bases, and Heteroatoms on Proximal Radial Distribution Functions for Proteins.

Science.gov (United States)

Nguyen, Bao Linh; Pettitt, B Montgomery

2015-04-14

The proximal distribution of water around proteins is a convenient method of quantifying solvation. We consider the effect of charged and sulfur-containing amino acid side-chain atoms on the proximal radial distribution function (pRDF) of water molecules around proteins using side-chain analogs. The pRDF represents the relative probability of finding any solvent molecule at a distance from the closest or surface perpendicular protein atom. We consider the near-neighbor distribution. Previously, pRDFs were shown to be universal descriptors of the water molecules around C, N, and O atom types across hundreds of globular proteins. Using averaged pRDFs, a solvent density around any globular protein can be reconstructed with controllable relative error. Solvent reconstruction using the additional information from charged amino acid side-chain atom types from both small models and protein averages reveals the effects of surface charge distribution on solvent density and improves the reconstruction errors relative to simulation. Solvent density reconstructions from the small-molecule models are as effective and less computationally demanding than reconstructions from full macromolecular models in reproducing preferred hydration sites and solvent density fluctuations.

A malonitrile-functionalized metal-organic framework for hydrogen sulfide detection and selective amino acid molecular recognition

Science.gov (United States)

Li, Haiwei; Feng, Xiao; Guo, Yuexin; Chen, Didi; Li, Rui; Ren, Xiaoqian; Jiang, Xin; Dong, Yuping; Wang, Bo

2014-03-01

A novel porous polymeric fluorescence probe, MN-ZIF-90, has been designed and synthesized for quantitative hydrogen sulfide (H2S) fluorescent detection and highly selective amino acid recognition. This distinct crystalline structure, derived from rational design and malonitrile functionalization, can trigger significant enhancement of its fluorescent intensity when exposed to H2S or cysteine molecules. Indeed this new metal-organic framework (MOF) structure shows high selectivity of biothiols over other amino acids and exhibits favorable stability. Moreover, in vitro viability assays on HeLa cells show low cytotoxicity of MN-ZIF-90 and its imaging contrast efficiency is further demonstrated by fluorescence microscopy studies. This facile yet powerful strategy also offers great potential of using open-framework materials (i.e. MOFs) as the novel platform for sensing and other biological applications.

Physiological function and ecological aspects of fatty acid-amino acid conjugates in insects.

Science.gov (United States)

Yoshinaga, Naoko

2016-07-01

In tritrophic interactions, plants recognize herbivore-produced elicitors and release a blend of volatile compounds (VOCs), which work as chemical cues for parasitoids or predators to locate their hosts. From detection of elicitors to VOC emissions, plants utilize sophisticated systems that resemble the plant-microbe interaction system. Fatty acid-amino acid conjugates (FACs), a class of insect elicitors, resemble compounds synthesized by microbes in nature. Recent evidence suggests that the recognition of insect elicitors by an ancestral microbe-associated defense system may be the origin of tritrophic interactions mediated by FACs. Here we discuss our findings in light of how plants have customized this defense to be effective against insect herbivores, and how some insects have successfully adapted to these defenses.

Molecular dynamics simulations of the amino acid-ZnO (10-10) interface: A comparison between density functional theory and density functional tight binding results

Energy Technology Data Exchange (ETDEWEB)

Holthaus, Svea große; Köppen, Susan, E-mail: koeppen@hmi.uni-bremen.de; Frauenheim, Thomas; Ciacchi, Lucio Colombi [Bremen Centre for Computational Materials Science, University of Bremen, 28359 Bremen (Germany)

2014-06-21

We investigate the adsorption behavior of four different amino acids (glutamine, glutamate, serine, cysteine) on the zinc oxide (101{sup ¯}0) surface, comparing the geometry and energy associated with a number of different adsorption configurations. In doing this, we highlight the benefits and limits of using density-functional tight-binding (DFTB) with respect to standard density functional theory (DFT). The DFTB method is found to reliably reproduce the DFT adsorption geometries. Analysis of the adsorption configurations emphasizes the fundamental role of the first hydration layer in mediating the interactions between the amino acids and the surface. Direct surface-molecule bonds are found to form predominantly via the carboxylate groups of the studied amino acids. No surface-mediated chemical reactions are observed, with the notable exception of a proton transfer from the thiol group of cysteine to a hydroxyl group of the surface hydration layer. The adsorption energies are found to be dominated both by the formation of direct or indirect surface-molecule hydrogen bonds, but also by the rearrangement of the hydrogen-bond network in surface proximity in a non-intuitive way. Energetic comparisons between DFTB and DFT are made difficult on one side by the long time necessary to achieve convergence of potential energy values in MD simulations and on the other side by the necessity of including higher-order corrections to DFTB to obtain a good description of the hydrogen bond energetics. Overall, our results suggest that DFTB is a good reference method to set the correct chemical states and the initial geometries of hybrid biomolecule/ZnO systems to be simulated with non-reactive force fields.

Molecular dynamics simulations of the amino acid-ZnO (10-10) interface: a comparison between density functional theory and density functional tight binding results.

Science.gov (United States)