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Sample records for acid oligomers constituents

  1. Comparison of automated pre-column and post-column analysis of amino acid oligomers

    Chow, J.; Orenberg, J. B.; Nugent, K. D.

    1987-01-01

    It has been shown that various amino acids will polymerize under plausible prebiotic conditions on mineral surfaces, such as clays and soluble salts, to form varying amounts of oligomers (n = 2-6). The investigations of these surface reactions required a quantitative method for the separation and detection of these amino acid oligomers at the picomole level in the presence of nanomole levels of the parent amino acid. In initial high-performance liquid chromatography (HPLC) studies using a classical postcolumn o-phthalaldehyde (OPA) derivatization ion-exchange HPLC procedure with fluorescence detection, problems encountered included lengthy analysis time, inadequate separation and large relative differences in sensitivity for the separated species, expressed as a variable fluorescent yield, which contributed to poor quantitation. We have compared a simple, automated, pre-column OPA derivatization and reversed-phase HPLC method with the classical post-column OPA derivatization and ion-exchange HPLC procedure. A comparison of UV and fluorescent detection of the amino acid oligomers is also presented. The conclusion reached is that the pre-column OPA derivatization, reversed-phase HPLC and UV detection produces enhanced separation, improved sensitivity and faster analysis than post-column OPA derivatization, ion-exchange HPLC and fluorescence detection.

  2. Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid and methylglyoxal

    Y. Tan

    2012-01-01

    Full Text Available Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including pyruvate, oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA. Acetic acid plays a central role in the aqueous oxidation of methylglyoxal and it is a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid (20 μM–10 mM was oxidized by OH radicals, and pyruvic acid and methylglyoxal experimental samples were analyzed using new analytical methods, in order to better understand the formation of SOA from acetic acid and methylglyoxal. Glyoxylic, glycolic, and oxalic acids formed from acetic acid and OH radicals. In contrast to the aqueous OH radical oxidation of methylglyoxal, the aqueous OH radical oxidation of acetic acid did not produce succinic acid and oligomers. This suggests that the methylgloxal-derived oligomers do not form through the acid catalyzed esterification pathway proposed previously. Using results from these experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

  3. Preparation and properties of poly(acrylic acid) oligomer stabilized superparamagnetic ferrofluid.

    Lin, Chia-Lung; Lee, Chia-Fen; Chiu, Wen-Yen

    2005-11-15

    Ferrofluids, which are stable dispersions of magnetic particles, behave as liquids that have strong magnetic properties. Nanoparticles of magnetite with a mean diameter of 10-15 nm, which are in the range of superparamagnetism, are usually prepared by the traditional method of co-precipitation from ferrous and ferric electrolyte solution. When diluted, the ferrofluid dispersions are not stable if anionic or cationic surfactants are used as the stabilizer. This work presents an efficient way to prepare a stable aqueous nanomagnetite dispersion. A stable ferrofluid containing Fe3O4 nanoparticles was synthesized via co-precipitation in the presence of poly(acrylic acid) oligomer. The mechanism, microstructure, and properties of the ferrofluid were investigated. The results indicate that the PAA oligomers promoted the nucleation and inhibited the growth of the magnetic iron oxide, and the average diameter of each individual Fe3O4 particle was smaller than 10 nm. In addition, the PAA oligomers provided both electrostatic and steric repulsion against particle aggregation, and the stability of dispersions could be controlled by adjusting the pH value of solution. A small amount of Fe2O3 was found in the nanoparticles but the superparamagnetic behavior of the nanoparticles was not affected. PMID:16009367

  4. Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid

    Y. Tan

    2011-06-01

    Full Text Available Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA. Acetic acid is an important intermediate in aqueous methylglyoxal oxidation and a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. Altieri et al. (2008 proposed that acetic acid was the precursor of oligoesters observed in methylglyoxal oxidation. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid at concentrations relevant to atmospheric waters (20 μM–10 mM was oxidized by OH radical. Products were analyzed by ion chromatography (IC, electrospray ionization mass spectrometry (ESI-MS, and IC-ESI-MS. The formation of glyoxylic, glycolic, and oxalic acids were observed. In contrast to methylglyoxal oxidation, succinic acid and oligomers were not detected. Using results from these and methylglyoxal + OH radical experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

  5. Kinetic properties of two Rhizopus exo-polygalacturonase enzymes hydrolyzing galacturonic acid oligomers using isothermal titration calorimetry

    The kinetic characteristics of two Rhizopus oryzae exo-polygalacturonases acting on galacturonic acid oligomers (GalpA) were determined using isothermal titration calorimetry (ITC). RPG15 hydrolyzing (GalpA)2 demonstrated a Km of 55 uM and kcat of 10.3 s^-1^ while RPG16 was shown to have greater af...

  6. Solution structure of hyaluronic acid oligomers by experimental and theoretical NMR, and molecular dynamics simulation.

    Donati, A; Magnani, A; Bonechi, C; Barbucci, R; Rossi, C

    2001-11-01

    The conformational properties of hyaluronic acid (HA) oligomers in aqueous solution were investigated by combining high-resolution NMR experimental results, theoretical simulation of NMR two-dimensional (2D) spectra by Complete Relaxation Matrix Analysis (CORMA), and molecular dynamics calculations. New experimental findings recorded for the tetra- and hexasaccharides enabled the stiffness of the HA and its viscoelastic properties to be interpreted. In particular, rotating frame nuclear Overhauser effect spectroscopy spectra provided new information about the arrangement of the glycosidic linkage. From (13)C NMR relaxation the rotational correlation time (tau(c)) were determined. The tau(c) were employed in the calculation of geometrical constraints, by using the MARDIGRAS algorithm. Restrained simulated annealing and 1 ns of unrestrained molecular dynamic simulations were performed on the hexasaccharide in a box of 1215 water molecules. The beta(1 --> 3) and beta(1 --> 4) glycosidic links were found to be rigid. The lack of rotational degree of freedom is due to direct and/or water-mediated interresidue hydrogen bonding. Both single or tandem water bridges were found between carboxylate group and N-acetil group. The carboxylate group of glucuronic acid is not involved in a direct link with the amide group of N-acetyl glucosamine and this facilitated bonding between the residue and the water molecules. PMID:11598878

  7. Iodinated hyaluronic acid oligomer-based nanoassemblies for tumor-targeted drug delivery and cancer imaging.

    Lee, Jae-Young; Chung, Suk-Jae; Cho, Hyun-Jong; Kim, Dae-Duk

    2016-04-01

    Nano-sized self-assemblies based on amphiphilic iodinated hyaluronic acid (HA) were developed for use in cancer diagnosis and therapy. 2,3,5-Triiodobenzoic acid (TIBA) was conjugated to an HA oligomer as a computed tomography (CT) imaging modality and a hydrophobic residue. Nanoassembly based on HA-TIBA was fabricated for tumor-targeted delivery of doxorubicin (DOX). Cellular uptake of DOX from nanoassembly, compared to a DOX solution group, was enhanced via an HA-CD44 receptor interaction, and subsequently, the in vitro antitumor efficacy of DOX-loaded nanoassembly was improved in SCC7 (CD44 receptor positive squamous cell carcinoma) cells. Cy5.5, a near-infrared fluorescence (NIRF) dye, was attached to the HA-TIBA conjugate and the in vivo tumor targetability of HA-TIBA nanoassembly, which is based on the interaction between HA and CD44 receptor, was demonstrated in a NIRF imaging study using an SCC7 tumor-xenografted mouse model. Tumor targeting and cancer diagnosis with HA-TIBA nanoassembly were verified in a CT imaging study using the SCC7 tumor-xenografted mouse model. In addition to efficient cancer diagnosis using NIRF and CT imaging modalities, improved antitumor efficacies were shown. HA and TIBA can be used to produce HA-TIBA nanoassembly that may be a promising theranostic nanosystem for cancers that express the CD44 receptor. PMID:26874284

  8. Peptide nucleic acid (PNA) cell penetrating peptide (CPP) conjugates as carriers for cellular delivery of antisense oligomers

    Shiraishi, Takehiko; Nielsen, Peter E

    2012-01-01

    We have explored the merits of a novel delivery strategy for the antisense oligomers based on cell penetrating peptide (CPP) conjugated to a carrier PNA with sequence complementary to part of the antisense oligomer. The effect of these carrier CPP-PNAs was evaluated by using antisense PNA targeting...... splicing correction of the mutated luciferase gene in the HeLa pLuc705 cell line, reporting cellular (nuclear) uptake of the antisense PNA via luciferase activity measurement. Carrier CPP-PNA constructs were studied in terms of construct modification (with octaarginine and/or decanoic acid) and carrier PNA...... length (to adjust binding affinity). In general, the carrier CPP-PNA constructs including the ones with decanoyl modification provided significant increase of the activity of unmodified antisense PNA as well as of antisense octaarginine-PNA conjugates. Antisense activity, and by inference cellular...

  9. High-affinity triplex targeting of double stranded DNA using chemically modified peptide nucleic acid oligomers

    Hansen, Mads E; Bentin, Thomas; Nielsen, Peter E

    2009-01-01

    While sequence-selective dsDNA targeting by triplex forming oligonucleotides has been studied extensively, only very little is known about the properties of PNA-dsDNA triplexes-mainly due to the competing invasion process. Here we show that when appropriately modified using pseudoisocytosine...... substitution, in combination with (oligo)lysine or 9-aminoacridine conjugation, homopyrimidine PNA oligomers bind complementary dsDNA targets via triplex formation with (sub)nanomolar affinities (at pH 7.2, 150 mM Na(+)). Binding affinity can be modulated more than 1000-fold by changes in pH, PNA oligomer...... length, PNA net charge and/or by substitution of pseudoisocytosine for cytosine, and conjugation of the DNA intercalator 9-aminoacridine. Furthermore, 9-aminoacridine conjugation also strongly enhanced triplex invasion. Specificity for the fully matched target versus one containing single centrally...

  10. High-affinity triplex targeting of double stranded DNA using chemically modified peptide nucleic acid oligomers

    Hansen, Mads E.; Bentin, Thomas; Nielsen, Peter E.

    2009-01-01

    While sequence-selective dsDNA targeting by triplex forming oligonucleotides has been studied extensively, only very little is known about the properties of PNA–dsDNA triplexes—mainly due to the competing invasion process. Here we show that when appropriately modified using pseudoisocytosine substitution, in combination with (oligo)lysine or 9-aminoacridine conjugation, homopyrimidine PNA oligomers bind complementary dsDNA targets via triplex formation with (sub)nanomolar affinities (at pH 7....

  11. Milk minor constituents, enzymes, hormones, growth factors, and organic acids

    Rodrigues, L. R.

    2013-01-01

    Milk and derived products contain essential nutrients, such as proteins, lactose, minerals, vitamins, and enzymes. Additionally, despite of their low concentrations in milk, many other minor constituents present important physiological and/or technological roles (e.g. hormones, growth factors). Dairy industries face many challenges regarding milk processing. Also, the full knowledge on these constituents’ physiological roles and effects on health is still lacking. Technological...

  12. Mapping the landscape of potentially primordial informational oligomers: (3'→2')-D-phosphoglyceric acid linked acyclic oligonucleotides tagged with 2,4-disubstituted 5-aminopyrimidines as recognition elements.

    Hernández-Rodríguez, Marcos; Xie, Jian; Osornio, Yazmin M; Krishnamurthy, Ramanarayanan

    2011-05-01

    The (3'→2')-phosphodiester glyceric acid backbone containing an acyclic oligomer tagged with 2,4-disubstituted pyrimidines as alternative recognition elements have been synthesized. Strong cross-pairing of a 2,4-dioxo-5-aminopyrimidine hexamer, rivaling locked nucleic acid (LNA) and peptide nucleic acid (PNA), with complementary adenine-containing DNA and RNA sequences was observed. The corresponding 2,4-diamino- and 2-amino-4-oxo-5-aminopyrimidine-tagged oligomers were synthesized, but difficulties in deprotection, purification, and isolation thwarted further investigations. The acyclic phosphate backbone structure of the protected oligomer seems to be prone to an eliminative degradation owing to the acidic hydrogen at the 2'-position--an arrangement that renders the oligomer vulnerable to the conditions used for the removal of the protecting groups on the heterocyclic recognition element. However, the free oligomers seem to be stable under the conditions investigated. PMID:21387563

  13. Optimizing the Acid Catalyzed Synthesis of Hyperbranched Poly(Glycerol-diacids) Oligomers

    Oligomeric pre-polymers were synthesized by the acid-catalyzed condensation of glycerol with succinic acid, glutaric acid and azelaic acid in dimethylsulfoxide (DMSO) or dimethylformamide (DMF). The prepolymers were obtained, on average in 84% yield, and were characterized by proton NMR, MALDI-TOF ...

  14. The effect of the dietary constituent conjugated linoleic acid and homocysteine on vascular endothelial cell function

    Coen, Paul Martin

    2004-01-01

    The interaction between circulating dietary constituents and the vascular endothelial monolayer is vital to the proper maintenance o f vascular homeostatic mechanisms, such as vasoregulation. Endothelial dysfunction with subsequent loss of vasoregulatory function are implicated in the early stages of atherosclerosis. Conjugated linoleic acid (CLA) and homocysteine are dietary constituents that have been implicated in the aetiology of atherosclerosis. CLA is the collective term used for po...

  15. Photo-crosslinked networks prepared from fumaric acid monoethyl ester-functionalized poly(D,L-lactic acid) oligomers and N-vinyl-2-pyrrolidone for the controlled and sustained release of proteins

    Jansen, Janine; Tibbe, Martijn P.; Mihov, George; Feijen, Jan; Grijpma, Dirk W.

    2012-01-01

    Photo-crosslinked networks were prepared from fumaric acid monoethyl ester-functionalized poly (D,L-lactic acid) oligomers and N-vinyl-2-pyrrolidone. Two model proteins, lysozyme and albumin, were incorporated into the network films as solid particles and their release behavior was studied. By varyi

  16. Application of CCT Technique to Simulate Vibrational Spectra of Nucleic Acid Oligomers

    Andrushchenko, Valery; Bouř, Petr

    Lviv : -, 2011. s. 41-41. [Methods and Applications of Computational Chemistry. International Symposium /4./. 28.06.2011-02.07.2011, Lviv] R&D Projects: GA ČR GAP208/10/0559; GA ČR GAP208/11/0105 Grant ostatní: AV ČR(CZ) M200550902 Institutional research plan: CEZ:AV0Z40550506 Keywords : IR spectroscopy * VCD spectroscopy * quantum chemistry spectra simulations * Cartesian coordinate transfer (CCT) * nucleic acids Subject RIV: CF - Physical ; Theoretical Chemistry

  17. Fundamental Interactions between Deoxyribonucleic Acid (DNA) Oligomers and Au Nanoparticles: Experimental and Theoretical Studies

    Karna, Molleshree; Balu, Radhakrishnan; Griep, Mark; Mallick, Govind

    2011-03-01

    Experimental and theoretical investigations were performed to understand the nature of fundamental interactions between gold nanoparticles (GNPs) and single stranded DNA (ss-DNA). Atomic force microscopic imaging and UV-Visible spectroscopic measurements revealed binding of NPs with ss-DNA under mildly acidic conditions.. Ab initio quantum chemical calculations within the framework of density functional theory provided a possible charge transfer pathway from the DNA base guanine to Au atoms and thus characterizing the interaction as electrostatic. The calculations outline the possible effect of the presence of other bases to guanine mediated charge transfer. Specifically, the presence of an adenine base alters the charge localization at the guanine base and thus prevents charge transfer to NPs.

  18. Crystal structure of a partly self-complementary peptide nucleic acid (PNA) oligomer showing a duplex-triplex network

    Petersson, Britt; Nielsen, Bettina Bryde; Rasmussen, Hanne;

    2005-01-01

    Hoogsteen type. The structural diversity of this PNA demonstrates how the PNA backbone is able to adapt to structures governed by the stacking and hydrogen-bonding interactions between the nucleobases. The crystal structure further shows how PNA oligomers containing limited sequence complementarity may form...

  19. Acanthoic acid and other constituents from the stem of Annoma amazonica (Annonaceae)

    Pinheiro, Maria Lucia B.; Xavier, Clahildek M.; Souza, Afonso D.L. de; Rabelo, Diego de Moura [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Dept. de Quimica], e-mail: lbelem@ufam.edu.br; Batista, Cristiane L.; Batista, Regiane L.; Costa, Emmanuel V.; Campos, Francinete R.; Barison, Anderson [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Centro Politecnico. Dept. de Quimica; Valdez, Rodrigo H.; Ueda-Nakamura, Tania; Nakamura, Celso V. [Universidade Estadual de Maringa (UEM), PR (Brazil). Dept. de Analises Clinicas], e-mail: lbelem@ufam.edu.br

    2009-07-01

    The present work reports the isolation of acanthoic acid, a promising pimaradiene-type diterpene with several important biological activities described in the literature, from the stems of Annona amazonica. We found that acanthoic acid has significant trypanocidal activity against the epimastigote forms of Trypanosoma cruzi. This diterpene is the major constituent of the plant, comprising at least 65% of the hexane extract, demonstrating that A. amazonica is a new renewable natural source for this compound. The chemical investigation also resulted in the isolation of the alkaloids liriodenine and cassythicine, and other compounds including terpenes, sterols, and fatty acids. Additionally, the complete and unequivocal {sup 1}H and {sup 13}C NMR chemical shift assignments for cassythicine are provided. (author)

  20. Acanthoic acid and other constituents from the stem of Annoma amazonica (Annonaceae)

    The present work reports the isolation of acanthoic acid, a promising pimaradiene-type diterpene with several important biological activities described in the literature, from the stems of Annona amazonica. We found that acanthoic acid has significant trypanocidal activity against the epimastigote forms of Trypanosoma cruzi. This diterpene is the major constituent of the plant, comprising at least 65% of the hexane extract, demonstrating that A. amazonica is a new renewable natural source for this compound. The chemical investigation also resulted in the isolation of the alkaloids liriodenine and cassythicine, and other compounds including terpenes, sterols, and fatty acids. Additionally, the complete and unequivocal 1H and 13C NMR chemical shift assignments for cassythicine are provided. (author)

  1. Investigation of the atmospheric behavior of dicarboxylic acids and other polar organic aerosol constituents

    The objective of the present work was to improve the present knowledge about the atmospheric behavior of polar organic aerosol constituents with special respect to dicarboxylic acids. To enable the simultaneous determination of polar organic compounds in atmospheric samples like aerosol or precipitation samples (atmospheric hydrometeors) a new GCMS method was developed. Almost all classes of oxygenated organic compounds like mono- and dicarboxylic acids, aldehydes, alcohols or polar aromatic compounds like phthalates could be determined with only one sample preparation scheme. The separation into two classes of organic compounds with different polarity was performed using solid phase extraction. After a sample pre-treatment of the derived fractions, including esterification of the acids and extraction with cyclohexane, the samples were analyzed with a GCMS system. The new method was applied for the analysis of simultaneously collected interstitial aerosol and cloud water samples from a continental background site in Central Europe (Sonnblick Observatory, located at 3106-m elevation in the Austrian Alps). In all samples a large variety of mono- and dicarboxylic acids were identified and quantified, together with some aldehydes, alcohols and aromatic compounds. Using the obtained data set, for the first time in-cloud scavenging efficiencies for dicarboxylic acids, monocarboxylic acids, and other polar organic compounds were calculated. The results were compared to sulfate, which exhibited an average scavenging efficiency of 0.94. In the last part of the present work the results from laboratory and field investigations conducted with the intention to yield an improved sampling technique for the correction of the positive sampling artifact (adsorption of gas phase organics onto the filter substrate) were presented. (author)

  2. The impact of hyaluronic acid oligomer content on physical, mechanical, and biologic properties of divinyl sulfone-crosslinked hyaluronic acid hydrogels.

    Ibrahim, Samir; Kang, Qian K; Ramamurthi, Anand

    2010-08-01

    In recent studies, we showed that exogenous hyaluronic acid oligomers (HA-o) stimulate functional endothelialization, though native long-chain HA is more bioinert and possibly more biocompatible. Thus, in this study, hydrogels containing high molecular weight (HMW) HA (1 x 10(6) Da) and HA-o mixtures (HA-o: 0.75-10 kDa) were created by crosslinking with divinyl sulfone (DVS). The incorporation of HA-o was found to compromise the physical and mechanical properties of the gels (rheology, apparent crosslinking density, swelling ratio, degradation) and to very mildly enhance inflammatory cell recruitment in vivo; increasing the DVS crosslinker content within the gels in general, had the opposite effect, though the relatively high concentration of DVS within these gels (necessary to create a solid gel) also stimulated a mild subcutaneous inflammatory response in vivo and VCAM-1 expression by endothelial cells (ECs) cultured atop; ICAM-expression levels remained very low irrespective extent of DVS crosslinking or HA-o content. The greatest EC attachment and proliferation (MTT assay) was observed on gels that contained the highest amount of HA-o. The study shows that the beneficial EC response to HA-o and biocompatibility of HA is mostly unaltered by their chemical derivatization and crosslinking into a hydrogel. However, the study also demonstrates that the relatively high concentrations of DVS, necessary to create solid gels, compromise their biocompatibility. Moreover, the poor mechanics of even these heavily crosslinked gels, in the context of vascular implantation, necessitates the investigation of other, more appropriate crosslinking agents. Alternately, the outcomes of this study may be used to guide an approach based on chemical immobilization and controlled surface-presentation of both bioactive HA-o and more biocompatible HMW HA on synthetic or tissue engineered grafts already in use, without the use of a crosslinker, so that improved, predictable, and

  3. Induction of volatile organic compound in the leaves of Lycopersicon esculentum by chitosan oligomer

    He Peiqing; Lin Xuezheng; Shen Jihong; Huang Xiaohang; Chen Kaoshan; Li Guangyou

    2005-01-01

    Induction of VOCs (volatile organic compounds) in the leaves of Lycopersicon esculentum by chitosan oligomer elictor was studied. The results demonstrated that VOCs in chitosan oligomer-treated leaves showed stronger inhibitory activity against Botrytis cinerea than that in water-treated leaves, and the spore germination was reduced by 22.1% in 144h after elicitor treatment at a concentration of 1.0%. A total of 16 constituents were detected in water-treated leaves, and chitosan oligomer treatment increased the amount of VOCs production. Chitosan oligomer at different concentration and different time courses of induction treatment could induce different amount of VOCs. Chitosan oligomer resulted in an optimal production of VOCs in 144h after elicitation at concentration of 0.6%. Chitosan oligomer also enhanced activtity of PAL and LOX. The results showed that the enhancement of VOCs production after chitosan oligomer treatment might be an important agent for L.esculentum acquiring resistance against pathogen.

  4. Radiation curable oligomers

    A process is described for the high energy radiation curing of oligomers for use as coatings. The method is particularly applicable to the reaction products of certain low molecular weight epoxy compounds and certain low molecular weight mono-hydroxy vinyl compounds having at least one vinylic unsaturation. The curable mixture is applied as a thin film and cured very quickly

  5. Electrorheology of aniline oligomers

    Mrlík, M.; Sedlačík, M.; Pavlínek, V.; Bober, Patrycja; Trchová, Miroslava; Stejskal, Jaroslav; Sáha, P.

    2013-01-01

    Roč. 291, č. 9 (2013), s. 2079-2086. ISSN 0303-402X R&D Projects: GA ČR GA202/09/1626 Institutional support: RVO:61389013 Keywords : anilin e oligomers * polyaniline * electrorheology Subject RIV: JI - Composite Materials Impact factor: 2.410, year: 2013

  6. Fatty acid constituents of Peganum harmala plant using Gas Chromatography-Mass Spectroscopy.

    Moussa, Tarek A A; Almaghrabi, Omar A

    2016-05-01

    Fatty acid contents of the Peganum harmala plant as a result of hexane extraction were analyzed using GC-MS. The saturated fatty acid composition of the harmal plant was tetradecanoic, pentadecanoic, tridecanoic, hexadecanoic, heptadecanoic and octadecanoic acids, while the saturated fatty acid derivatives were 12-methyl tetradecanoic, 5,9,13-trimethyl tetradecanoic and 2-methyl octadecanoic acids. The most abundant fatty acid was hexadecanoic with concentration 48.13% followed by octadecanoic with concentration 13.80%. There are four unsaturated fatty acids called (E)-9-dodecenoic, (Z)-9-hexadecenoic, (Z,Z)-9,12-octadecadienoic and (Z,Z,Z)-9,12,15-octadecatrienoic. The most abundant unsaturated fatty acid was (Z,Z,Z)-9,12,15-octadecatrienoic with concentration 14.79% followed by (Z,Z)-9,12-octadecadienoic with concentration 10.61%. Also, there are eight non-fatty acid compounds 1-octadecene, 6,10,14-trimethyl-2-pentadecanone, (E)-15-heptadecenal, oxacyclohexadecan-2 one, 1,2,2,6,8-pentamethyl-7-oxabicyclo[4.3.1]dec-8-en-10-one, hexadecane-1,2-diol, n-heneicosane and eicosan-3-ol. PMID:27081366

  7. Aniline oligomers versus polyaniline

    Stejskal, Jaroslav; Trchová, Miroslava

    2012-01-01

    Roč. 61, č. 2 (2012), s. 240-251. ISSN 0959-8103 R&D Projects: GA AV ČR IAA400500905; GA AV ČR IAA100500902; GA ČR GA203/08/0686; GA ČR GA202/09/1626 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * anilin e oligomers * anilin e Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.125, year: 2012

  8. Aniline oligomers versus polyaniline

    Stejskal, Jaroslav; Trchová, Miroslava

    Strasbourg : InESS, Université de Strasbourg, CNRS, 2011. s. 69. [Congrés Matériaux et Nanostructures .pi.-conjugués 2011 - MNPC 11. 03.10.2011-07.10.2011, Obernai] R&D Projects: GA ČR GA202/09/1626 Institutional research plan: CEZ:AV0Z40500505 Keywords : anilin e oligomers * conducting polymer * polyaniline microspheres Subject RIV: BK - Fluid Dynamics

  9. 香青兰酚酸性化学成分的研究%Phenolic Acid Constituents from Dracocephalum moldavica

    吴小军; 宋建晓; 赵爱华; 贾伟

    2011-01-01

    从香青兰(Dracocephalum moldavica L.)乙醇提取物乙酸乙酯部位中分离得到8个酚酸性化合物,经过理化性质、波谱分析及文献对照,分别鉴定为amburoside A(1)、阿魏酸(2)、咖啡酸(3)、迷迭香酸(4)、迷迭香酸甲酯(5)、木犀草素(6)、山奈酚(7)和β-胡萝卜苷(8).其中化合物1~5为首次从该植物中分离得到.%To investigate the Phenolic acid constituents of Dracocephalum moldavica L, eight compounds were isolated and purified by silica gel and Sephadex LH-20 column chromatography. The compound structures were identified as amburoside A ( 1 ), ferulic acid ( 2 ), caffeic acid (3), rosmarinic acid ( 4 ), methyl rosmarinate ( 5 ), luteolin ( 6 ),kaempferol (7) ,and β-daucosterol (8) based on their spectral data. Among them,compounds 1-5 were obtained from this plant for the first time.

  10. Effects of Exogenous Indole Butyric Acid and Callus Formation on the Anti-oxidant Activity, Total Phenolic, and Anthocyanin Constituents of Mulberry Cuttings

    2006-01-01

    In order to evaluate the effects of exogenous indole butyric acid (IBA) and callus formation on the antioxidant activity, total phenolics, and anthocyanin constituents of Morus nigra L. and M. alba L. cuttings, we investigated the variations before and after the treatment. The results indicate that anti-oxidant ability, total phenolic, and anthocyanin constituents of the callus stems of both Morus species were higher than those of non-callus forming species. There were also increases observed in anti-oxidant ability, total phenolic,and anthocyanin constituents of calli treated with IBA (1 000-3 000 mg/L).

  11. Icariin, a major constituent from Epimedium brevicornum, attenuates ibotenic acid-induced excitotoxicity in rat hippocampus.

    Zong, Nan; Li, Fei; Deng, Yuanyuan; Shi, Jingshan; Jin, Feng; Gong, Qihai

    2016-10-15

    Excitotoxicity is one of the most extensively studied causes of neuronal death and plays an important role in Alzheimer's disease (AD). Icariin is a flavonoid component of a traditional Chinese medicine reported to possess a broad spectrum of pharmacological effects. The present study was designed to investigate the effects of icariin against learning and memory impairment induced by excitotoxicity. Here, we demonstrated that rats receiving intracerebroventricular injection of excitatory neurotoxin ibotenic acid exhibited impaired learning and memory. Oral administration of icariin at doses of 20 and 40mg/kg rescued behavioral performance and protected against neurotoxicity in rat hippocampus by suppressing ibotenic acid induced pro-apoptosis. Furthermore, Western blott of hippocampal specimens revealed that icariin up-regulated the expression of calbindin-D28k protein following ibotenic acid administration. Additionally, icariin inhibited mitogen-activated protein kinase (MAPK) family phosphorylation and nuclear factor kappa B (NF-κB) signaling, implicating the MAPK signaling and NF-κB signaling pathways were involved in the mechanism underlying icariin-mediated neuroprotection against ibotenic acid-induced excitotoxicity. These data suggested that icariin could be a potential agent for treatment of excitotoxicity-related diseases, including AD. PMID:27368415

  12. Oxygen uptake in the radiolysis of aqueous solutions of nucleic acids and their constituents

    G (O2 uptake) has been measured for 27 compounds in N2O/O2 (4:1)- saturated solutions using an oxygen sensitive electrode. G (O2 uptake) (measured at 200C and dose rate of 0.4 Gy s-1) for isopropanol (3.0), sodium formate (3.0), D-glucose (3.2), 2deoxy-D-ribose (3.0), t-butanol (4.2) and diethyl ether (4.5) were found to be in agreement with the expectation based on product yields and/or known mechanisms. High O2 uptake was observed with polyethyleneoxide (10.2), which increases with decreasing dose rate and/or increasing temperature (G(O2 uptake) = 40 at 0.04 Gy s-1 and 500C). These results are explained by assuming a chain reaction. The nucleotides 5'-thymidylic acid (4.4), 5'-deoxy-cytidylic acid (4.8), 5'-deoxyadenylic acid (1.9) and 5'-deoxyguanylic acid (1.6) show that the pyrimidine derivatives consume considerably more oxygen than the purine derivatives. Analogous results are obtained with the nucleobases and nucleosides. The pyrimidine-purine difference is even more pronounced in the corresponding polymer, poly U (21) and poly A (3.5). The large value of poly U shows that a significant contribution of a chain reaction is present. G(O2 uptake) for DNA is dose-rate, temperature and concentration-dependent. The O2 uptake for single-stranded DNA (6.8) and double-stranded DNA (4.6) is higher than for an equivalent mixture of nucleotides (3.2). These results indicate that in DNA also a short chain reaction takes place. (author)

  13. Mushroom tyrosinase inhibitory activity and major fatty acid constituents of Amazonian native flora oils

    Raquel da Silva Teixeira; Paula Rafaela Rocha; Hudson Caetano Polonini; Marcos Antônio Fernandes Brandão; Maria das Graças Afonso Miranda Chaves; Nádia Rezende Barbosa Raposo

    2012-01-01

    In order to treat hyperpigmentation-related problems, there has been a global trend in developing cosmetics claiming to have skin-whitening properties, which act by inhibiting melanin biosynthesis. The objective of this work was to evaluate the in vitro mushroom tyrosinase inhibitory activity of five Amazonian native flora oils, and so to verify the possibility of their incorporation into cosmetic products. In addition, the fatty acid composition of the essential oils was determined by gas ch...

  14. Mushroom tyrosinase inhibitory activity and major fatty acid constituents of Amazonian native flora oils

    Raquel da Silva Teixeira

    2012-09-01

    Full Text Available In order to treat hyperpigmentation-related problems, there has been a global trend in developing cosmetics claiming to have skin-whitening properties, which act by inhibiting melanin biosynthesis. The objective of this work was to evaluate the in vitro mushroom tyrosinase inhibitory activity of five Amazonian native flora oils, and so to verify the possibility of their incorporation into cosmetic products. In addition, the fatty acid composition of the essential oils was determined by gas chromatography-flame ionisation detection in order to determine the main components of these oils. The tyrosinase inhibitory activity of the tested oils was found to be in the following order: açaí (IA50 = 66.08 µg mL-1 > tucumã > patauá > pracaxi > castanha do Brasil. This study suggests that açaí oil has great potential in the treatment of hyperpigmentation and other related disorders, due to its considerable tyrosinase inhibitory activity.Com o intuito de se tratar problemas dermatológicos de hiperpigmentação, há uma tendência mundial no desenvolvimento de cosméticos que possuam propriedades despigmentantes, os quais agem inibindo a biossíntese de melanina. O objetivo deste trabalho foi avaliar in vitro a atividade de inibição da tirosinase de cogumelo de cinco óleos de plantas nativas da Amazônia e, desta forma, verificar a possibilidade de sua incorporação em produtos cosméticos. Ainda, a composição de ácidos graxos dos óleos foi determinada por cromatografia gasosa com detecção por ionização de chama, no intuito de determinar os principais componentes destes óleos. A atividade de inibição da tirosinase dos óleos testados foi encontrada na seguinte ordem: açaí (IA50 = 66,08 µg mL-1 > tucumã > patauá > pracaxi > castanha do Brasil. Este estudo sugere que o óleo de açaí possui grande potencial para o tratamento da hiperpigmentação cutânea e doenças correlatas, devido à sua considerável atividade de inibi

  15. A comparison of simultaneous plasma, atomic absorption, and iron colorimetric determinations of major and trace constituents in acid mine waters

    Ball, J.W.; Nordstrom, D.K.

    1994-01-01

    Sixty-three water samples collected during June to October 1982 from the Leviathan/Bryant Creek drainage basin were originally analyzed by simultaneous multielement direct-current plasma (DCP) atomic-emission spectrometry, flame atomic-absorption spectrometry, graphite-furnace atomic-absorption spectrometry (GFAAS) (thallium only), ultraviolet-visible spectrometry, and hydride-generation atomic-absorption spectrometry.Determinations were made for the following metallic and semi-metallic constituents: AI, As, B, Ba, Be, Bi, Cd, Ca, Cr, Co, Cu, Fe(11), Fe(total), Li, Pb, Mg, Mn, Mo, Ni, K, Sb, Se, Si, Na, Sr, TI, V, and Zn. These samples were re-analyzed later by simultaneous multielement inductively coupled plasma (ICP) atomic-emission spectrometry and Zeeman-corrected GFAAS to determine the concentrations of many of the same constituents with improved accuracy, precision, and sensitivity. The result of this analysis has been the generation of comparative concentration values for a significant subset of the solute constituents. Many of the more recently determined values replace less-than-detection values for the trace metals; others constitute duplicate analyses for the major constituents. The multiple determinations have yielded a more complete, accurate, and precise set of analytical data. They also have resulted in an opportunity to compare the performance of the plasma-emission instruments operated in their respective simultaneous multielement modes. Flame atomic-absorption spectrometry was judged best for Na and K and hydride-generation atomic-absorption spectrometry was judged best for As because of their lower detection limit and relative freedom from interelement spectral effects. Colorimetric determination using ferrozine as the color agent was judged most accurate, precise, and sensitive for Fe. Cadmium, lead, and vanadium concentrations were too low in this set of samples to enable a determination of whether ICP or DCP is a more suitable technique. Of

  16. Quality of Norwegian cucumbers: effect of greenhouse praxis on taste and taste related constituents, and GC-FID analysis on content of fatty acids and aldehydes

    Johnsen, Linda Renate

    2014-01-01

    Earlier studies have shown that sugars (SSC), salts (EC) and the relationships between sugars/salts and sugars/acids (TTA- total titratable acids) may impact taste in cucumber. In this study, the impacts of environmental conditions in greenhouses on appearance, taste, and content of taste related constituents in cucumber are examined. Cucumber were sampled from eight different greenhouses, and analyzed regarding appearance of morphological featur...

  17. PIPERIDINE OLIGOMERS AND COMBINATORIAL LIBRARIES THEREOF

    1999-01-01

    The present invention relates to piperidine oligomers, methods for the preparation of piperidine oligomers and compound libraries thereof, and the use of piperidine oligomers as drug substances. The present invention also relates to the use of combinatorial libraries of piperidine oligomers for...... libraries (arrays) of compounds especially suitable for screening purposes....

  18. Conformation dependent monoclonal antibodies distinguish different replicating strains or conformers of prefibrillar Aβ oligomers

    Yeung Stephen

    2010-12-01

    Full Text Available Abstract Background Age-related neurodegenerative diseases share a number of important pathological features, such as accumulation of misfolded proteins as amyloid oligomers and fibrils. Recent evidence suggests that soluble amyloid oligomers and not the insoluble amyloid fibrils may represent the primary pathological species of protein aggregates. Results We have produced several monoclonal antibodies that specifically recognize prefibrillar oligomers and do not recognize amyloid fibrils, monomer or natively folded proteins. Like the polyclonal antisera, the individual monoclonals recognize generic epitopes that do not depend on a specific linear amino acid sequence, but they display distinct preferences for different subsets of prefibrillar oligomers. Immunological analysis of a number of different prefibrillar Aβ oligomer preparations show that structural polymorphisms exist in Aβ prefibrillar oligomers that can be distinguished on the basis of their reactivity with monoclonal antibodies. Western blot analysis demonstrates that the conformers defined by the monoclonal antibodies have distinct size distributions, indicating that oligomer structure varies with size. The different conformational types of Aβ prefibrillar oligomers can serve as they serve as templates for monomer addition, indicating that they seed the conversion of Aβ monomer into more prefibrillar oligomers of the same type. Conclusions These results indicate that distinct structural variants or conformers of prefibrillar Aβ oligomers exist that are capable of seeding their own replication. These conformers may be analogous to different strains of prions.

  19. Effect of dietary supplementation of gallic acid on nitrogen balance, nitrogen excretion pattern and urinary nitrogenous constituents in beef cattle.

    Wei, Chen; Yang, Kai; Zhao, Guangyong; Lin, Shixin; Xu, Zhiwei

    2016-10-01

    The objective of the trial was to study the effects of dietary supplementation of gallic acid (GA) on nitrogen (N) balance, N excretion pattern and urinary N constituents in beef cattle. In a 4 × 4 Latin square design, four male 30-month-old Simmental cattle (443 ± 22 kg live weight) received four levels of GA (purity ≥ 98.5%), i.e. 0, 5.3, 10.5, 21.1 g/kg DM, added to a basal ration. Each experimental period lasted 17 d, consisting of 12 d adaptation and 5 d sampling. The results showed that supplementation of GA at 5.3, 10.5 or 21.1 g/kg DM did not affect the N balance but regulated the N excretion pattern by increasing the ratio of faecal N/urinary N and decreasing the ratio of urinary urea N/total urinary N in beef cattle fed at maintenance level. PMID:27494638

  20. MALDI-FTMS for the characterization of ultraviolet and X-ray damage to nucleic acid constituents

    Both low energy (far-ultraviolet) and high energy (X-ray) radiation can cause DNA damage by inducing strand breaks, base modifications, and sugar alternations. These changes may lead to mutations and ultimately cell death if they cannot be biologically repaired. It is therefore necessary to characterize both the identities (at the isomeric level) and the abundances of the radiation-induced products to probe the nature of DNA damage in these cases. Matrix-assisted laser desorption/ionization Fourier transform mass spectroscopy (MALDI-FTMS) is well-suited for the direct detection and characterization of radiation-induced damage to nucleic acid constituents, including oligonucleotides. This technique eliminates the need to hydrolyze and derivatize the samples prior to mass analysis, thereby reducing the possibility of modifying the sample after irradiation. The accurate mass measurement and ion trapping capabilities of FTMS permit the detailed examination of the structures of these products. Reverse phase liquid chromatography (HPLC) is used to purify irradiated samples prior to mass analysis to quantitate the dose dependent formation of products after they have been identified by mass spectrometry

  1. Preparation of Chito-Oligomers by Hydrolysis of Chitosan in the Presence of Zeolite as Adsorbent

    Khalid A. Ibrahim

    2016-07-01

    Full Text Available An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as immuno-enhancing effects on animals. Conventional depolymerization methods of chitosan to chito-oligomers are either chemical by acid-hydrolysis under harsh conditions or by enzymatic degradation. In this work, hydrolysis of chitosan to chito-oligomers has been achieved by applying adsorption-separation technique using diluted HCl in the presence of different types of zeolite as adsorbents. The chito-oligomers were retrieved from adsorbents and characterized by differential scanning calorimetry (DSC, liquid chromatography/mass spectroscopy (LC/MS, and ninhydrin test.

  2. Preparation of Chito-Oligomers by Hydrolysis of Chitosan in the Presence of Zeolite as Adsorbent.

    Ibrahim, Khalid A; El-Eswed, Bassam I; Abu-Sbeih, Khaleel A; Arafat, Tawfeeq A; Al Omari, Mahmoud M H; Darras, Fouad H; Badwan, Adnan A

    2016-01-01

    An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers) in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as immuno-enhancing effects on animals. Conventional depolymerization methods of chitosan to chito-oligomers are either chemical by acid-hydrolysis under harsh conditions or by enzymatic degradation. In this work, hydrolysis of chitosan to chito-oligomers has been achieved by applying adsorption-separation technique using diluted HCl in the presence of different types of zeolite as adsorbents. The chito-oligomers were retrieved from adsorbents and characterized by differential scanning calorimetry (DSC), liquid chromatography/mass spectroscopy (LC/MS), and ninhydrin test. PMID:27455287

  3. Green approach to corrosion inhibition of mild steel in two acidic solutions by the extract of Punica granatum peel and main constituents

    Behpour, M., E-mail: m.behpour@kashanu.ac.ir [Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, I.R. 87317-51167 (Iran, Islamic Republic of); Ghoreishi, S.M.; Khayatkashani, M. [Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, I.R. 87317-51167 (Iran, Islamic Republic of); Soltani, N. [Department of Chemistry, Payame Noor University (PNU), 19395-4697 Tehran (Iran, Islamic Republic of)

    2012-01-05

    Graphical abstract: Ellagic acid (EA) and tannic acid (TA) were studied as corrosion inhibitors. The electron density HOMO and LUMO of EA and TA were used to explain difference in behavior of them. Highlights: Black-Right-Pointing-Pointer The extract of Punica granatum (PG) and their main constituent (ellagic acid (EA)) are found to be good inhibitors for the corrosion of mild steel in 1 M H{sub 2}SO{sub 4} and 2 M HCl. Black-Right-Pointing-Pointer The electrochemical inhibitive mechanism is explained by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) results. Black-Right-Pointing-Pointer The adsorption of ALLOX on mild steel surface was found to accord with the Temkin adsorption isotherm. Black-Right-Pointing-Pointer The effect of temperature on the corrosion behavior of mild steel in 2 M HCl and 1 M H{sub 2}SO{sub 4} without and with the PG extract was studied. - Abstract: The effect of the extract of Punica granatum (PG) and their main constituents involve ellagic acid (EA) and tannic acid (TA), as mild steel corrosion inhibitor in 2 M HCl and 1 M H{sub 2}SO{sub 4} solutions was investigated by weight loss measurements. The results obtained from the weight loss measurements show that the inhibition efficiency of TA even in high concentration is very low. Thus, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) investigations were used for different concentrations of PG and EA and best concentration of TA. Potentiodynamic polarization curves indicated that PG and EA behave as mixed-type inhibitors. EIS measurements show an increase of the transfer resistance with increasing inhibitor concentration. The temperature effect on the corrosion behavior of steel without and with the PG extract was studied. The inhibition action of the extract was discussed in view of Langmuir adsorption isotherm.

  4. Green approach to corrosion inhibition of mild steel in two acidic solutions by the extract of Punica granatum peel and main constituents

    Graphical abstract: Ellagic acid (EA) and tannic acid (TA) were studied as corrosion inhibitors. The electron density HOMO and LUMO of EA and TA were used to explain difference in behavior of them. Highlights: ► The extract of Punica granatum (PG) and their main constituent (ellagic acid (EA)) are found to be good inhibitors for the corrosion of mild steel in 1 M H2SO4 and 2 M HCl. ► The electrochemical inhibitive mechanism is explained by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) results. ► The adsorption of ALLOX on mild steel surface was found to accord with the Temkin adsorption isotherm. ► The effect of temperature on the corrosion behavior of mild steel in 2 M HCl and 1 M H2SO4 without and with the PG extract was studied. - Abstract: The effect of the extract of Punica granatum (PG) and their main constituents involve ellagic acid (EA) and tannic acid (TA), as mild steel corrosion inhibitor in 2 M HCl and 1 M H2SO4 solutions was investigated by weight loss measurements. The results obtained from the weight loss measurements show that the inhibition efficiency of TA even in high concentration is very low. Thus, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) investigations were used for different concentrations of PG and EA and best concentration of TA. Potentiodynamic polarization curves indicated that PG and EA behave as mixed-type inhibitors. EIS measurements show an increase of the transfer resistance with increasing inhibitor concentration. The temperature effect on the corrosion behavior of steel without and with the PG extract was studied. The inhibition action of the extract was discussed in view of Langmuir adsorption isotherm.

  5. Effect of humic constituents on the transformation of chlorinated phenols and anilines in the presence of oxidoreductive enzymes or birnessite

    Park, J.W.; Dec, J.; Bollag, J.M. (Pennsylvania State Univ., University Park, PA (United States)); Kim, J.E. (Kyngpook National Univ., Taegu (Korea, Republic of). Dept. of Agricultural Chemistry)

    1999-06-15

    Chlorinated phenols and anilines are transformed and detoxified in soil through oxidative coupling reactions mediated by enzymes or metal oxides. The reactions may be influences by humic constituents, such as syringaldehyde or catechol, that originate from lignin decomposition and are also subject to oxidative coupling. In this study, the effect of humic constituents on xenobiotic transformation was evaluated in vitro based on the determination of unreacted chlorophenols and chloroanilines. In experiments with peroxidase, laccase, and birnessite, the transformation of most chlorophenols was considerably enhanced by the addition of syringaldehyde. Less enhancement was observed using 4-hydroxybenzoic acid, and the addition of catechol resulted in a reduction of most transformations. The opposite was observed in experiments with tyrosinase, in which case catechol caused considerable enhancement of chlorophenol transformation. The varying effect of catechol can be explained by different transformation mechanisms involving either o-quinone coupling or free radical coupling. Regardless of the agent used to mediate the reactions, chloroanilines seemed to undergo nucleophilic addition to quinone oligomers, which resulted from coupling of the humic constituents. Catechol, which readily forms quinones and quinone oligomers, was most efficient in enhancing these reactions.

  6. Caffeoylquinic Acids Are Major Constituents with Potent Anti-Influenza Effects in Brazilian Green Propolis Water Extract

    Tomohiko Urushisaki; Tomoaki Takemura; Shigemi Tazawa; Mayuko Fukuoka; Junji Hosokawa-Muto; Yoko Araki; Kazuo Kuwata

    2011-01-01

    Influenza A viral infections reached pandemic levels in 1918, 1957, 1968, and, most recently, in 2009 with the emergence of the swine-origin H1N1 influenza virus. The development of novel therapeutics or prophylactics for influenza virus infection is urgently needed. We examined the evaluation of the anti-influenza virus (A/WSN/33 (H1N1)) activity of Brazilian green propolis water extract (PWE) and its constituents by cell viability and real-time PCR assays. Our findings showed strong eviden...

  7. Synthesis and properties of photo-curable silicone (meth)acrylate oligomers

    Photo-curable resins are widely used in various applications such as coatings, adhesives and inks, due to their high efficiencies, environmental friendly technology and saving of energy. Silicone (meth) acrylate oligomers offer an excellent slip property because of their low surface tension. In addition, they can enhance other properties like chemical resistance and heat resistance. In this research, photo-curable silicone (meth) acrylate oligomers are prepared from modified PDMS (polydimethyl siloxane) polyols, diisocyanate, carboxylic acid and hydroxyl (meth) acrylate to evaluate basic property of these oligomers. (Author)

  8. Effect of abscisic acid on biochemical constituents, enzymatic and non enzymatic antioxidant status of lettuce (Lactuca sativa L. under varied irrigation regimes

    Mohamed A. Al Muhairi

    2015-12-01

    Full Text Available Economically important vegetable crop lettuce (Lactuca sativa L. of family Asteraceae was selected for the present investigation. It is being cultivated in UAE due to its commercial importance. In lettuce cultivation, the major problem is the requirement of large quantities of irrigation water. The present study was aimed to reduce the water consumption of lettuce cultivation; for that, a varied irrigation regime was used with the application of abscisic acid (ABA. The parameters studied were biochemical constituents, antioxidant potential and antioxidant enzymes’ activities in lettuce plants under drought stress and its response to ABA under stress. Drought stress caused an increase in the biochemical constituents like proline and amino acid contents when compared with control and also increased under individual ABA treatments and treatments under drought stress. The non-enzymatic antioxidant molecules like ascorbate and α-tocopherol showed significant increase under drought condition in lettuce. ABA slightly reduced these contents. The antioxidant enzymes like superoxide dismutase, catalase and peroxidase showed significant increase under drought condition and ABA caused significant enhancement in these antioxidant enzymes under drought stress and also in unstressed conditions, thereby protecting the plants from the deleterious effects of drought stress. From the results of this investigation, it can be concluded that ABA in 10 mg g−1 can be used as a potential tool to minimise the drought stress effects in lettuce cultivation.

  9. Oxymer - a new class of aliphatic polycarbonate oligomers improving the properties of radiation curable systems

    In this paper a new class of aliphatic polycarbonate oligomers that greatly improves the properties of radiation curable systems is presented. Through the use of these oligomers hydrolytic stability and outdoor durability can be achieved without compromising any other aspect of the coating performance making it deal for many interior as well as exterior applications such as automotive coatings and UV adhesives. In addition, the chemical constituents of this new class of aliphatic polycarbonates awards low surface energy making them suitable for coating of low surface energy substrates e.g within the field of graphic arts. (Author)

  10. 端羟基聚乳酸低聚物的制备与性能研究%Preparation and Properties of Hydroxyl Terminated Polylactic Acid Oligomer

    张苗苗; 常军; 杨超; 张恒; 许贺

    2015-01-01

    以左旋乳酸和1,4-丁二醇为原料,氯化亚锡(SnCl2・2H2O)和辛酸亚锡(Sn(OCT)2)为催化剂通过熔融缩聚法合成端羟基聚乳酸(HO-PLLA-OH)。熔融缩聚反应工艺条件为:0.1%SnCl2・2H2O(mol%)和0.1%Sn(OCt)2(mol%),聚合温度控制在180℃,反应时间为10 h,并采用红外光谱(IR)、核磁共振谱(1H-NMR),测得产物黏均分子量(Mη)为9528,差示扫描热分析( DSC)等手段对聚合物的热性能进行了研究。低聚物在缓冲液中20天失重率为43.1%。%L-lactic acid and 1,4-butanediol were used to synthesize hydroxyl terminated PLLA( HO-PLLA-OH) by melt polycondensation with stannous chloride and stannous octoate as catalyst.The polymerization conditions was attributed as follows:the dose of SnCl2・ 2H2 O and Sn(OCT)2 reached 0.1%, polymerization temperature was 180℃, polymerization time was 10 h.The synthesized HO-PLLA-OH was detected by infrared spectroscopy ( IR) and proton nuclear magnetic resonance (1H-NMR).The viscosity-average molecular weight was exceeded 9528 detected by ubbelohde viscometer, and the thermal perproty was investigated by differential scanning calorimeter(DSC).Weight loss of HO-PLLA-OH was 43.1%in 20 days.

  11. Cellulose oligomers production and separation for the synthesis of new fully bio-based amphiphilic compounds.

    Billès, Elise; Onwukamike, Kelechukwu N; Coma, Véronique; Grelier, Stéphane; Peruch, Frédéric

    2016-12-10

    Cellulose oligomers are water-soluble, on the contrary to cellulose, which greatly increase their application range. In this study, cellulose oligomers were obtained from the acidic hydrolysis of cellulose with phosphoric acid. The global yield in water-soluble oligomers was around 23% with polymerization degree (DP) ranging from 1 to 12. The cellulose oligomers DP distribution was successfully reduced by differential solubilisation in methanol as one of the goals of this work was to avoid the use of a time-consuming full chromatographic separation. The methanol-soluble oligomers were mainly low DP (≤3). The oligomers of higher molar mass, composed of 42% of cellotetraose and 36% of cellopentaose, were then functionalized and coupled with stearic acid through azide-alkyne click chemistry to obtain amphiphilic compounds. The self-assembly of these new bio-based compounds was finally investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM) and their critical micellar concentration (CMC) was found to be in the same range as alkylmaltosides and alkylglucosides. PMID:27577903

  12. Ferroelectric and dielectric properties of electroactive oligomers and nanocomposites

    Kraemer, Kristin L.

    Polyvinylidene fluoride (PVDF) and its copolymers have been well established as ferroelectric polymers. The dielectric and ferroelectric properties for vinylidene fluoride (VDF) oligomer thin films were investigated. By synthesizing oligomers instead of long polymer chains, films with higher crystalinity can be formed and the locations of oligomers can be controlled for applications such as molecular electronics. Evidence of ferroelectricity was observed in oligomer thin films evaporated onto room temperature substrates and by Langmuir-Blodgett (LB) deposition. Voltage and frequency dependence of the capacitance was measured. Oligomers functionalized with phosphonic acid formed self-assembled monolayers (SAM) on aluminum and mica substrates. Film thickness was measured by ellipsometry and atomic force microscopy (AFM). The time dependence on film growth was measured for SAMs on mica substrates by AFM. The islands had already formed by 1 minute, and by 1 hour film was continuous. Additionally, studies were performed on composite dielectric systems with the goal of fabricating high energy density dielectrics containing nanoparticles with an organic shell. The first two types of samples had barium titante nanoparticles coated with functionalized alkanes or VDF oligomers. The first sample type consisted of coated nanoparticles embedded in a PVDF copolymer or terpolymer spin-coated film. At low particle concentrations, the matrix properties dominated the electrical measurements while at high concentrations, the samples were electrically fragile. The second sample type consisted of alternating layers of LB terpolymer and LB nanoparticles. These samples allowed for high particle concentrations while maintaining the high breakdown strength of the polymer layers. The final type of sample was titanium dioxide nanoparticles formed by cluster deposition and coated with an evaporated paraffin or VDF oligomer. These samples tended to have low breakdown strengths and poor

  13. Effect of blanching, dehydration method and temperature on the ascorbic acid, colour, sliminess and other constituents of okra fruit.

    Inyang, U E; Ike, C I

    1998-03-01

    Freshly harvested okra fruits were blanched in boiling water (with or without 0.2% sodium metablsulphite salt) and the effect of this treatment, dehydration methods and temperature on certain characteristics of okra investigated. Blanching resulted in the slight decrease in carbohydrate, fat, ash, colour components, ascorbic acid and viscosity. Besides this initial loss, blanching in sulphite solution led to the retention of more of the colour components and ascorbic acid during dehydration. All dehydrated okra samples had higher contents of carbohydrate, fat and ash but lesser contents of protein and ascorbic acid than fresh okra. Fresh okra fruits, on the other hand, had higher content of the colour pigments and were more viscous than all dehydrated products. Samples blanched prior to dehydration retained more of the colour components but were less viscous than unblanched samples. Vacuum dehydrated samples retained more ascorbic acid, colour pigment and mucilage at each of the dehydration temperatures than those from a hot air oven. High dehydration temperatures had negative effect on the colour, ascorbic acid and viscosity of okra. PMID:9713583

  14. 蝉翼藤茎中有机酸成分的研究%Organic Acid Constituents from the Stem of Securidaca inappendiculata Hassk.

    杨学东; 徐丽珍; 杨世林

    2001-01-01

    Objective:To investigate the organic acid constituents from the stem of Securidaca inappendiculata.Method:Column chromatographic techniques were used to isolate and purify the constituents.The structures were elucidated by spectra analysis.Result:Five compounds were isolated and identified as ferulic acid(Ⅰ), cinnamic acid(Ⅱ), palmic acid(Ⅲ), salicylic acid(Ⅳ) and benzoic acid(Ⅴ).Conclusion:Compounds Ⅰ~Ⅳ were isolated from the plant for the first time.%目的:对蝉翼藤茎中有机酸成分进行化学研究。方法:各种色谱技术进行分离纯化,理化性质和光谱分析进行结构鉴定。结果:分离得到5个有机酸类化合物,分别鉴定为阿魏酸(Ⅰ)、肉桂酸(Ⅱ)、棕榈酸(Ⅲ)、水杨酸(Ⅳ) 和苯甲酸(Ⅴ)。结论:化合物Ⅰ~Ⅳ为首次从该属植物中分离得到。

  15. Prion protein oligomer and its neurotoxicity

    Pei Huang; Fulin Lian; Yi Wen; Chenyun Guo; Donghai Lin

    2013-01-01

    The prion diseases,also known as transmissible spongiform encephalopathies,are fatal neurodegenerative disorders.According to the 'protein only' hypothesis,the key molecular event in the pathogenesis of prion disease is the conformational conversion of the host-derived cellular prion protein (PrPC) into a misfolded form (scrapie PrP,prpSc).Increasing evidence has shown that the most infectious factor is the smaller subfibrillar oligomers formed by prion proteins.Both the prion oligomer and PrPSc are rich in β-sheet structure and resistant to the proteolysis of proteinase K.The prion oligomer is soluble in physiologic environments whereas PrPSc is insoluble.Various prion oligomers are formed in different conditions.Prion oligomers exhibited more neurotoxicity both in vitro and in vivo than the fibrillar forms of PrPSc,implying that prion oligomers could be potential drug targets for attacking prion diseases.In this article,we describe recent experimental evidence regarding prion oligomers,with a special focus on prion oligomer formation and its neurotoxicity.

  16. E.S.R. of spin-trapped radicals in gamma-irradiated polycrystalline nucleic acid constituents and their halogenated derivatives

    Free radicals in γ-irradiated polycrystalline nucleic acid constituents and their 5-halogenated derivatives have been studied by e.s.r. and spin-trapping. After γ-irradiation at room temperature, the polycrystalline samples were dissolved in aqueous solutions of t-nitrosobutane (tNB) in the absence or presence of oxygen. For many of the nucleic acid constituents two types of radicals, -C(5)RH-C(6)H- and -C(5)R-C(6)H2-, formed by H-addition to the double bond [-C(5)R = C(6)H-] of the base, were observed, where R is -CH3 or -H. In addition, radicals formed on the sugar moiety were found for some nucleosides. When oxygen was present in the tNB solution, the relative stability of trapped radicals was changed, and thus the presence of more than one radical species could be established. For halogenated bases, the radical produced by H-abstraction from N(1) was observed, and an additional radical species formed by H-addition to the C(6) position was found for 5-fluorouracil. For halogenated nucleosides, the same spectrum was observed in all compounds except the 5-fluoroderivatives, and was assigned to the radicals produced on the sugar moiety. For 5-fluorodeoxyuridine and 5-fluorouridine, the radical formed by H-addition to the C(6) position of the base was observed. In general, the present results are in good agreement with those of previous single crystal studies, but in the case of halogenated compounds other than the 5-fluoroderivatives, it was not possible to spin-trap the α-halo radicals which were the most prominent radicals formed from γ-irradiation of single crystals at room temperature. (author)

  17. Effects of protein deficiency on the rate of radioactivity loss from body constituents in adult rats given 14C-amino acids

    The effect of protein deficiency on the rate of loss of radioactivity from body constituents was studied in adult rats administered 14C-Chlorella protein hydrolysate or 14C-lysine. Rats were kept on a protein-free diet for 3 weeks and then injected with labelled amino acids and fed on a protein-free diet for 3 more days to allow 14C deposition in tissues. Then they were given experimental diets (protein-free diet, 1% and 10% wheat gluten diets pair-fed with the protein-free diet, and 10% wheat gluten diet ad libitum) for 7 days and sacrificed. The rates of loss of radioactivity from tissue proteins became low in general with the extent of protein deficiency. This increased capacity of tissues to retain 14C-amino acids may result from higher efficiency of protein utilization in protein deficiency. The reutilization of free amino acids and the rate of catabolism of tissue protein are discussed on the basis of the results. The half-life of muscle protein was too long to observe the effects of experimental diets given for 7 days on the rate of loss of radioactivity. (auth.)

  18. Justification for Selecting Level A vs. Level B Personal Protective Equipment to Remediate a Room Containing Concentrated Acids, Bases and Radiological Constituents

    Selecting the appropriate personal protective equipment (PPE) is based on providing an adequate level of employee protection relative to the task-specific conditions and hazards. PPE is categorized into four ensembles, based on the degree of protection afforded; e.g., Levels A (most restrictive), B, C, and D (least restrictive). What is often overlooked in preparing an ensemble is that the PPE itself can create significant worker hazards; i.e., the greater the level of PPE, the greater the associated risks. Furthermore, there is confusion as to whether a more ''conservative approach'' should always be taken since Level B provides the same level of respiratory protection as Level A but less skin protection. This paper summarizes the Occupational Safety and Health Administration regulations addressing Level A versus Level B, and provides justification for selecting Level B over Level A without under-protecting the employee during a particular remediation scenario. The scenario consisted of an entry team performing (1) an initial entry into a room containing concentrated acids (e.g., hydrofluoric acid), bases, and radiological constituents; (2) sampling and characterizing container contents; and (3) retrieving characterized containers. The invasive nature of the hydrofluoric acid sampling and characterization scenario created a high potential for splash, immersion, and exposure to hazardous vapors, requiring additional skin protection. The hazards associated with this scenario and the chemical nature of hydrofluoric acid provided qualitative evidence to justify Level A. Once the hydrofluoric acid was removed from the room, PPE performance was evaluated against the remaining chemical inventory. If chemical breakthrough from direct contact was not expected to occur and instrument readings confirmed the absence of any hazardous vapors, additional skin protection afforded by wearing a vapor-tight, totally-encapsulated suit was not required. Therefore, PPE performance and

  19. Protective Effect of Safranal, a Constituent of Crocus sativus, on Quinolinic Acid-induced Oxidative Damage in Rat Hippocampus

    Hamid Reza Sadeghnia

    2013-01-01

    Full Text Available Objective(s: Quinolinic acid (QA-mediated excitotoxicity has been widely used as a model for studying neurodegenerative disorders. Recent studies suggested that saffron (Crocus sativus or its active metabolite, i.e. safranal, exerts pharmacological actions on central nervous system including anxiolytic, anticonvulsant, and neuroprotective properties. The present study aimed to investigate the effect safranal pretreatment on QA-induced oxidative damage in rat hippocampus. Materials and Methods: Under anesthesia, a guide cannula was stereotaxically inserted into left ventral hippocampus of rats. The rats were then given either saline or safranal (72.75, 145.5, and 291 mg/kg, IP 30 min before administration of QA (300 nmol, intrahippocampal injection. The markers of oxidative stress including thiobarbituric acid reactive substances (TBARS, as an index of lipid preoxidation, total sulfhydryl groups, antioxidant capacity of hippocampus (using FRAP assay, and oxidative DNA damage (%tail DNA, using comet assay were measured in hippocampus. Results: The QA induced a significant increase in TBARS levels and %tail DNA and remarkable decrease in antioxidant power (FRAP value and total sulfhydryl content of hippocampus, in comparison with control animals. Systemic administration of safranal (291 mg/kg, IP, effectively and dose-dependently decreased the QA-induced lipid peroxidation (P

  20. Resolving the bulk δ 15N values of ancient human and animal bone collagen via compound-specific nitrogen isotope analysis of constituent amino acids

    Styring, Amy K.; Sealy, Judith C.; Evershed, Richard P.

    2010-01-01

    Stable nitrogen isotope analysis is a fundamental tool in assessing dietary preferences and trophic positions within contemporary and ancient ecosystems. In order to assess more fully the dietary contributions to human tissue isotope values, a greater understanding of the complex biochemical and physiological factors which underpin bulk collagen δ 15N values is necessary. Determinations of δ 15N values of the individual amino acids which constitute bone collagen are necessary to unravel these relationships, since different amino acids display different δ 15N values according to their biosynthetic origins. A range of collagen isolates from archaeological faunal and human bone ( n = 12 and 11, respectively), representing a spectrum of terrestrial and marine protein origins and diets, were selected from coastal and near-coastal sites at the south-western tip of Africa. The collagens were hydrolysed and δ 15N values of their constituent amino acids determined as N-acetylmethyl esters (NACME) via gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The analytical approach employed accounts for 56% of bone collagen nitrogen. Reconstruction of bulk bone collagen δ 15N values reveals a 2‰ offset from bulk collagen δ 15N values which is attributable to the δ 15N value of the amino acids which cannot currently be determined by GC-C-IRMS, notably arginine which comprises 53% of the nitrogen unaccounted for (23% of the total nitrogen). The δ 15N values of individual amino acids provide insights into both the contributions of various amino acids to the bulk δ 15N value of collagen and the factors influencing trophic position and the nitrogen source at the base of the food web. The similarity in the δ 15N values of alanine, glutamate, proline and hydroxyproline reflects the common origin of their amino groups from glutamate. The depletion in the δ 15N value of threonine with increasing trophic level indicates a fundamental difference between

  1. A study of aqueous solutions of nucleic acid constituents exposed to monochromatic 160 nm vacuum-UV light by spin-trapping method

    Spin-trapping technique was employed to detect and identify free radical intermediates produced in aqueous solutions of nucleic acid constituents (pyrimidine bases and pyrimidine nucleosides) after irradiation by monochromatic 160 nm vacuum-UV light from the electron storage ring. Short-lived free radicals produced in the molecules were converted into relatively long-lived free radicals (spin-adducts) by the reaction with MNP used as a spin trap. The resulting nitroxide radicals were subsequently analysed by esr. Clear evidence that most of the radicals were not formed by H-addition but formed by OH-addition at the C5 position of the 5,6 double bond were obtained for pyrimidine bases. For pyrimidine nucleosides, although the effect of H2O-D2O exchange was not recognized on resolution improvement of the hyperfine structure of the esr spectra, careful analysis of the hyperfine structure made it possible to identify the radical structures: OH-addition radicals at the C6 of the double bond of the base moiety in addition to the OH-addition radicals at the C5 position for all except for 2'-deoxycytidine. Evidence for the formation of free radicals at the sugar moiety was not clear. (author)

  2. Self-propagative replication of Aβ oligomers suggests potential transmissibility in Alzheimer disease.

    Amit Kumar

    Full Text Available The aggregation of amyloid-β (Aβ peptide and its deposition in parts of the brain form the central processes in the etiology of Alzheimer disease (AD. The low-molecular weight oligomers of Aβ aggregates (2 to 30 mers are known to be the primary neurotoxic agents whose mechanisms of cellular toxicity and synaptic dysfunction have received substantial attention in the recent years. However, how these toxic agents proliferate and induce widespread amyloid deposition throughout the brain, and what mechanism is involved in the amplification and propagation of toxic oligomer species, are far from clear. Emerging evidence based on transgenic mice models indicates a transmissible nature of Aβ aggregates and implicates a prion-like mechanism of oligomer propagation, which manifests as the dissemination and proliferation of Aβ toxicity. Despite accumulating evidence in support of a transmissible nature of Aβ aggregates, a clear, molecular-level understanding of this intriguing mechanism is lacking. Recently, we reported the characterization of unique replicating oligomers of Aβ42 (12-24 mers in vitro called Large Fatty Acid-derived Oligomers (LFAOs (Kumar et al., 2012, J. Biol. Chem. In the current report, we establish that LFAOs possess physiological activity by activating NF-κB in human neuroblastoma cells, and determine the experimental parameters that control the efficiency of LFAO replication by self-propagation. These findings constitute the first detailed report on monomer - oligomer lateral propagation reactions that may constitute potential mechanism governing transmissibility among Aβ oligomers. These data support the previous reports on transmissible mechanisms observed in transgenic animal models.

  3. Loop Sequence Context Influences the Formation and Stability of the i-Motif for DNA Oligomers of Sequence (CCCXXX)4, where X = A and/or T, under Slightly Acidic Conditions.

    McKim, Mikeal; Buxton, Alexander; Johnson, Courtney; Metz, Amanda; Sheardy, Richard D

    2016-08-11

    The structure and stability of DNA is highly dependent upon the sequence context of the bases (A, G, C, and T) and the environment under which the DNA is prepared (e.g., buffer, temperature, pH, ionic strength). Understanding the factors that influence structure and stability of the i-motif conformation can lead to the design of DNA sequences with highly tunable properties. We have been investigating the influence of pH and temperature on the conformations and stabilities for all permutations of the DNA sequence (CCCXXX)4, where X = A and/or T, using spectroscopic approaches. All oligomers undergo transitions from single-stranded structures at pH 7.0 to i-motif conformations at pH 5.0 as evidenced by circular dichroism (CD) studies. These folded structures possess stacked C:CH(+) base pairs joined by loops of 5'-XXX-3'. Although the pH at the midpoint of the transition (pHmp) varies slightly with loop sequence, the linkage between pH and log K for the proton induced transition is highly loop sequence dependent. All oligomers also undergo the thermally induced i-motif to single-strand transition at pH 5.0 as the temperature is increased from 25 to 95 °C. The temperature at the midpoint of this transition (Tm) is also highly dependent on loop sequence context effects. For seven of eight possible permutations, the pH induced, and thermally induced transitions appear to be highly cooperative and two state. Analysis of the CD optical melting profiles via a van't Hoff approach reveals sequence-dependent thermodynamic parameters for the unfolding as well. Together, these data reveal that the i-motif conformation exhibits exquisite sensitivity to loop sequence context with respect to formation and stability. PMID:27438583

  4. [Chemical constituents of Desmodium sambuense].

    Li, Chuankuan; Zhang, Qianjun; Huang, Zhongbi; Chen, Qing; Yao, Rongjun

    2010-09-01

    The chemical constituents of Desmodium sambuense were studied. Chromatographic techniques were applied to isolate and purify the constituents, and the structures were identified on the basis of physico-chemical and spectroscopeic methods. Thirteen compounds were isolated from the 75% ethanol extract of Desmodium sambuens and elucidated as beta-amyrin(1), betulic acid(2), daucosterol(3), triacontanoic acid(4), lup-20(29)-en-3-one(5), tetracosanoic-2,3-dihydroxypropylester(6), stigmast-5-ene-3beta, 7alpha-ol (7),methyl phaeophorbidea(8), o-hydroxy benzoic acid(9),beta-sitosterol(10),d-catechin(11), luteolin (12), epigallocatechin (13). All of the compounds were isolated from this plant for the first time. PMID:21141491

  5. Characterization of oligomers from methylglyoxal under dark conditions: a pathway to produce secondary organic aerosol through cloud processing during nighttime

    Yasmeen, F.; Sauret, N.; Gal, J.-F.; Maria, P.-C.; Massi, L.; Maenhaut, W.; Claeys, M.

    2010-04-01

    Aqueous-phase oligomer formation from methylglyoxal, a major atmospheric photooxidation product, has been investigated in a simulated cloud matrix under dark conditions. The aim of this study was to explore an additional pathway producing secondary organic aerosol (SOA) through cloud processes without participation of photochemistry during nighttime. Indeed, atmospheric models still underestimate SOA formation, as field measurements have revealed more SOA than predicted. Soluble oligomers (n = 1-8) formed in the course of acid-catalyzed aldol condensation and acid-catalyzed hydration followed by acetal formation have been detected and characterized by positive and negative ion electrospray ionization mass spectrometry. Aldol condensation proved to be a favorable mechanism under simulated cloud conditions, while hydration/acetal formation was found to strongly depend on the pH of the system and only occurred at a pHaldol oligomer series starts with a β-hydroxy ketone via aldol condensation, where oligomers are formed by multiple additions of C3H4O2 units (72 Da) to the parent β-hydroxy ketone. Ion trap mass spectrometry experiments were performed to structurally characterize the major oligomer species. A mechanistic pathway for the growth of oligomers under cloud conditions and in the absence of UV-light and OH radicals, which could substantially enhance in-cloud SOA yields, is proposed here for the first time.

  6. Aβ42-oligomer Interacting Peptide (AIP) neutralizes toxic amyloid-β42 species and protects synaptic structure and function

    Barucker, Christian; Bittner, Heiko J.; Chang, Philip K.-Y.; Cameron, Scott; Hancock, Mark A.; Liebsch, Filip; Hossain, Shireen; Harmeier, Anja; Shaw, Hunter; Charron, François M.; Gensler, Manuel; Dembny, Paul; Zhuang, Wei; Schmitz, Dietmar; Rabe, Jürgen P.; Rao, Yong; Lurz, Rudi; Hildebrand, Peter W.; McKinney, R. Anne; Multhaup, Gerhard

    2015-10-01

    The amyloid-β42 (Aβ42) peptide is believed to be the main culprit in the pathogenesis of Alzheimer disease (AD), impairing synaptic function and initiating neuronal degeneration. Soluble Aβ42 oligomers are highly toxic and contribute to progressive neuronal dysfunction, loss of synaptic spine density, and affect long-term potentiation (LTP). We have characterized a short, L-amino acid Aβ-oligomer Interacting Peptide (AIP) that targets a relatively well-defined population of low-n Aβ42 oligomers, rather than simply inhibiting the aggregation of Aβ monomers into oligomers. Our data show that AIP diminishes the loss of Aβ42-induced synaptic spine density and rescues LTP in organotypic hippocampal slice cultures. Notably, the AIP enantiomer (comprised of D-amino acids) attenuated the rough-eye phenotype in a transgenic Aβ42 fly model and significantly improved the function of photoreceptors of these flies in electroretinography tests. Overall, our results indicate that specifically “trapping” low-n oligomers provides a novel strategy for toxic Aβ42-oligomer recognition and removal.

  7. Report on the U.S. Geological Survey's evaluation program for standard reference samples distributed in October 1993 : T-127 (trace constituents), M-128 (major constituents), N-40 (nutrients), N-41 (nutrients), P-21 (low ionic strength), Hg-17 (mercury), AMW-3 (acid mine water), and WW-1 (whole water)

    Long, H.K.; Farrar, J.W.

    1994-01-01

    This report presents the results of the U.S. Geological Survey's analytical evaluation program for eight standard reference samples--T-127 (trace constituents), M-128 (major constituents), N-40 (nutrients), N-41 (nutrients), P-21 (low ionic strength), Hg-17 (mercury), AMW-3 (acid mine water), and WW-1 (whole water)--that were distributed in October 1993 to 158 laboratories registered in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data that were received from 145 of the laboratories were evaluated with respect to: overall laboratory performance and relative laboratory performance for each analyte in the eight reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the eight standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

  8. Electrografting of conductive oligomers and polymers using diazonium electroreduction

    This paper describes the attachment of conjugated oligomers onto electrode surface through the reduction of diazonium compounds. In this connection some properties of conjugated oligomers and of layers grafted through diazonium electroreduction will first be briefly presented. The electrochemical behavior of conjugated oligomers grafted on a surface using diazonium electroreduction will then be discussed. (paper)

  9. Resveratrol oligomers isolated from Carex species inhibit growth of human colon tumorigenic cells mediated by cell cycle arrest.

    González-Sarrías, Antonio; Gromek, Samantha; Niesen, Daniel; Seeram, Navindra P; Henry, Geneive E

    2011-08-24

    Research has shown that members of the Carex genus produce biologically active stilbenoids including resveratrol oligomers. This is of great interest to the nutraceutical industry given that resveratrol, a constituent of grape and red wine, has attracted immense research attention due to its potential human health benefits. In the current study, five resveratrol oligomers (isolated from Carex folliculata and Carex gynandra ), along with resveratrol, were evaluated for antiproliferative effects against human colon cancer (HCT-116, HT-29, Caco-2) and normal human colon (CCD-18Co) cells. The resveratrol oligomers included one dimer, two trimers, and two tetramers: pallidol (1); α-viniferin (2) and trans-miyabenol C (3); and kobophenols A (4) and B (5), respectively. Although not cytotoxic, the resveratrol oligomers (1-5), as well as resveratrol, inhibited growth of the human colon cancer cells. Among the six stilbenoids, α-viniferin (2) was most active against the colon cancer cells with IC(50) values of 6-32 μM (>2-fold compared to normal colon cells). Moreover, α-viniferin (at 20 μM) did not induce apoptosis but arrested cell cycle (in the S-phase) for the colon cancer but not the normal colon cells. This study adds to the growing body of knowledge supporting the anticancer effects of resveratrol and its oligomers. Furthermore, Carex species should be investigated for their nutraceutical potential given that they produce biologically active stilbenoids such as α-viniferin. PMID:21761862

  10. Peptide oligomers for holographic data storage

    Berg, Rolf Henrik; Hvilsted, Søren; Ramanujam, P.S.

    1996-01-01

    materials. Here we show that holographic gratings with large first-order diffraction efficiencies (up to 80%) can be written and erased optically in oligomer films only a few micrometres thick. The holograms also exhibit good thermal stability, and are not erased after heating to 180 degrees C for one month...

  11. Bioactive constituents in aronia berries

    2014-01-01

    The aim of this thesis was to investigate some of the potential health benefits of aronia berries with main focus on the phenolic substances. Extractions and fractionations of aronia berries were performed to obtain several crude extracts and subfractions. In addition, well known constituents of aronia berries (anthocyanins, procyanidins and phenolic acids) were isolated. The different samples obtained were then tested in various in vitro bioassays to determine their biological activities as ...

  12. Montmorillonite catalysis of RNA oligomer formation in aqueous solution. A model for the prebiotic formation of RNA

    Ferris, J. P.; Ertem, G.

    1993-01-01

    Oligomers of adenylic acid of up to the 11-mer in length are formed by the reaction of the phosphorimidazolide of adenosine (ImpA) in pH 8 aqueous solution at room temperature in the presence of Na(+)-montmorillonite. These oligomers are joined by phosphodiester bonds in which the 3',5'-linkage predominates over the 2',5'-linkage by a 2:1 ratio. Reaction of a 9:1 mixture of ImpA, A5'ppA results in the formation of oligomers with a 3:1 ratio of 3',5'- to 2',5'-linked phosphodiester bonds. A high proportion of these oligomers contain the A5'ppA grouping. A5'ppA reacts much more rapidly with ImpA than does 5'-ADP (ppA) or 5'-ATP (pppA). The exchangeable cation associated with the montmorillonite effects the observed catalysis with Li+, Na+, NH4+, and Ca2+ being the more effective while Mg2+ and Al3+ are almost ineffective catalysts. 2',5'-Linked oligomers, up to the tetramer in length, are formed using UO2(2+)-montmorillonite. The structure analysis of individual oligomer fractions was performed by selective enzymatic and KOH hydrolytic studies followed by HPLC analysis of the reaction products. It is concluded from the composition of the oligomers that the rate of addition ImpA to a 3'-terminus containing a 2',5'-linkage is slower than the addition to a nucleoside joined by a 3',5'-linked phosphodiester bond. The potential importance of mineral catalysis of the formation of RNA and other oligomers on primitive Earth is discussed.

  13. 鳄嘴花叶氨基酸和微量元素分析及其化学成分研究%Analysis of Amino Acids, Trace Elements and Chemical Constituents from the Leaves of Clinacanthus nutans

    易博; 徐文彤; 邓盾; 邓涛

    2012-01-01

    目的 分析鳄嘴花叶中的氨基酸、微量元素及主要化学成分.方法 采用HPLC法和等离子体发射光谱法测定了鳄嘴花叶中氨基酸和微量元素的成分和含量,采用柱色谱法对鳄嘴花叶中的主要化学成分进行研究.结果 从鳄嘴花叶中分析测定出了17种氨基酸和11种微量元素,叶中总氨基酸含量达11.54%.分离鉴定出4种主要化学成分,羽扇豆醇(1)、异牡荆苷(2)、β-胡萝卜苷(3)、肥皂草苷(4).结论 鳄嘴花叶富含大量的人体必需氨基酸、微量元素及活性天然产物,具有较高的营养价值和药用价值.%Objective To analyze amino acids, trace elements and chemical constituents from the leaves of Clinacanthus nutans . Methods The amino acids and trace elements were detected by HPLC and ICP-OES, respectively. Chemical constituents were identified by the combination of column chromatography and spectral analysis. Results The leaves contained seventeen varieties of amino acids, eleven trace elements, and four primary chemical components. Conclusion The leaves are rich in amino acids, trace elements and bioactive chemical constituents, suggesting that Clinacanthus nutans is of high nutritional value.

  14. Synthesis of Citric-Acrylate Oligomer and its in-Situ Reaction with Chrome Tanned Collagen (hide powder)

    The purpose of this study was to formulate the new combined system of acrylic and citric acids, which has been prepared by free radical polymerization and esterification reaction at the same time to form citric acrylate (CAC) oligomer through ester linkage and low molecular weight (Mw 2241), in compared with polyacrylic acid. The chemical structure and the reaction mechanism of this oligomer were confirmed by different spectroscopic tools (1H, 13C-NMR, ATR-IR), gel permeation chromatography and thermogravimetric analysis (TGA/DTA). The problem of the effect of the masking agents in the chrome tanning of the collagen and the pickling of the hide has been approached from the study of the hydrothermal and mechanical properties, using this new eco-friendly oligomer, which was carried out in-situ treated/grafted chrome tanned collagen (hide powder), and pickled hide. The microemulsion grafting copolymerization of (CAC) using 2.2-azo-bis isobutyronitrile (ABIN), via direct coupling reaction, onto the chrome tanned collagen showed that the free amino groups of the collagen were considered to be a potential site for the in-situ reaction with (CAC) oligomer. Also, using of citric-acrylate (CAC) oligomer, during chrome tanning of leather, instead of the traditional strong acids (sulfuric, hydrochloric and formic) resulted in significant improvement in chrome exhaustion and physical properties

  15. High in vitro antimicrobial activity of β-peptoid-peptide hybrid oligomers against planktonic and biofilm cultures of Staphylococcus epidermidis

    Liu, Yang; Knapp, Kolja Michael; Yang, Liang;

    2013-01-01

    An array of β-peptoid-peptide hybrid oligomers displaying different amino acid/peptoid compositions and chain lengths was studied with respect to antimicrobial activity against Staphylococcus epidermidis both in planktonic and biofilm cultures, comparing the effects with those of the common antib...... killing of bacterial cells. This class of peptidomimetics may constitute promising antimicrobial alternatives for the prevention and treatment of multidrug-resistant S. epidermidis infections.......An array of β-peptoid-peptide hybrid oligomers displaying different amino acid/peptoid compositions and chain lengths was studied with respect to antimicrobial activity against Staphylococcus epidermidis both in planktonic and biofilm cultures, comparing the effects with those of the common...

  16. Oligomer formation during gas-phase ozonolysis of small alkenes and enol ethers: new evidence for the central role of the Criegee Intermediate as oligomer chain unit

    A. Sadezky

    2008-05-01

    Full Text Available An important fraction of secondary organic aerosol (SOA formed by atmospheric oxidation of diverse volatile organic compounds (VOC has recently been shown to consist of high-molecular weight oligomeric species. In our previous study (Sadezky et al., 2006, we reported the identification and characterization of oligomers as main constituents of SOA from gas-phase ozonolysis of small enol ethers. These oligomers contained repeated chain units of the same chemical composition as the main Criegee Intermediates (CI formed during the ozonolysis reaction, which were CH2O2 (mass 46 for alkyl vinyl ethers (AVE and C2H4O2 (mass 60 for ethyl propenyl ether (EPE. In the present work, we extend our previous study to another enol ether (ethyl butenyl ether EBE and a variety of structurally related small alkenes (trans-3-hexene, trans-4-octene and 2,3-dimethyl-2-butene.

    Experiments have been carried out in a 570 l spherical glass reactor at atmospheric conditions in the absence of seed aerosol. SOA formation was measured by a scanning mobility particle sizer (SMPS. SOA filter samples were collected and chemically characterized off-line by ESI(+/TOF MS and ESI(+/TOF MS/MS, and elemental compositions were determined by ESI(+/FTICR MS and ESI(+/FTICR MS/MS. The results for all investigated unsaturated compounds are in excellent agreement with the observations of our previous study. Analysis of the collected SOA filter samples reveal the presence of oligomeric compounds in the mass range 200 to 800 u as major constituents. The repeated chain units of these oligomers are shown to systematically have the same chemical composition as the respective main Criegee Intermediate (CI formed during ozonolysis of the unsaturated compounds, which is C3H6O2 (mass 74 for ethyl butenyl ether (EBE, trans-3-hexene, and 2,3-dimethyl-2-butene, and C4H8

  17. Asymmetric Wave Propagation Through Saturable Nonlinear Oligomers

    Daniel Law

    2014-10-01

    Full Text Available In the present paper we consider nonlinear dimers and trimers (more generally, oligomers embedded within a linear Schrödinger lattice where the nonlinear sites are of saturable type. We examine the stationary states of such chains in the form of plane waves, and analytically compute their reflection and transmission coefficients through the nonlinear oligomer, as well as the corresponding rectification factors which clearly illustrate the asymmetry between left and right propagation in such systems. We examine not only the existence but also the dynamical stability of the plane wave states. Lastly, we generalize our numerical considerations to the more physically relevant case of Gaussian initial wavepackets and confirm that the asymmetry in the transmission properties also persists in the case of such wavepackets.

  18. Oligomer functionalized nanotubes and composites formed therewith

    Zettl, Alexander K; Sainsbury, Toby; Frechet, Jean M.J.

    2014-03-18

    Disclosed herein is a sequential functionalization methodology for the covalent modification of nanotubes with between one and four repeat units of a polymer. Covalent attachment of oligomer units to the surface of nanotubes results in oligomer units forming an organic sheath around the nanotubes, polymer-functionalized-nanotubes (P-NTs). P-NTs possess chemical functionality identical to that of the functionalizing polymer, and thus provide nanoscale scaffolds which may be readily dispersed within a monomer solution and participate in the polymerization reaction to form a polymer-nanotube/polymer composite. Formation of polymer in the presence of P-NTs leads to a uniform dispersion of nanotubes within the polymer matrix, in contrast to aggregated masses of nanotubes in the case of pristine-NTs. The covalent attachment of oligomeric units to the surface of nanotubes represents the formation of a functional nanoscale building block which can be readily dispersed and integrated within the polymer to form a novel composite material.

  19. Risk of oligomers in the textile industry

    Giachino, G.M.; Perrelli, G.; Passarino, G.; Comino, E.; Pira, E.; Scansetti, G.; Rubino, G.F.

    1982-11-01

    An experimental research was carried out at the Institute of Occupational Health of Turin University on the risks following exposure to oligomers with particular reference to the textile industry. A group of 36 Sprague-Dawley rats were injected endotracheally with a suspension of dust collected from various sections of twisting and spinning departments while 6 rats used as controls were treated with normal solution. Five rats had pneumonia and 1 rat showed the presence of aspecific granuloma; the histological patterns for the other rats were found to be similar to those of the control group. In the Authors' opinion it is impossible at the moment to give a definite conclusion as to the role of oligomers in lung damage.

  20. Self-assembly of aniline oligomers

    Zhao, Y.; Tomšík, Elena; Wang, J.; Morávková, Zuzana; Zhigunov, Alexander; Stejskal, Jaroslav; Trchová, Miroslava

    2013-01-01

    Roč. 8, č. 1 (2013), s. 129-137. ISSN 1861-4728 R&D Projects: GA ČR GA202/09/1626; GA ČR GAP205/12/0911 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : morphology * oligoaniline * oligomers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.935, year: 2013

  1. Scandium extraction by phenolformaldehyde resol oligomers

    Scandium extraction by phenolahrvaldehyde resol oligomers ''Yarresin B'', ''101 K'' and also by bis-(2-hydroxy-5-octylbenzyl)amine, bis-2-hydroxy-5-alkylbenzyl)amine and disulfide of p-alkylphenol was studied. It is shown that nitrogen-containing reagents, particularly ''Yarresin B'', extract scandium more effectively. Influence of time of phase contact, nitrogen content in ''Yarresin B'' composition on scandium extraction is studied, extraction isotherm is plotted

  2. Enzymatic hydrolysis of PTT polymers and oligomers

    Eberl, A.; Heumann, Sonja; Kotek, R.; Kaufmann, F; Mitscher, S.; Paulo, Artur Cavaco; Gübitz, Georg M.

    2008-01-01

    Oligomers and polymers (film, fabrics) of the linear aromatic polyester poly(trimethylene terephthalate) (PTT) were treated with polyesterases from Thermomyces lanuginosus, Penicillium citrinum, Thermobifida fusca and Fusarium solani pisi. The cutinase from T. fusca was found to release the highest amounts of hydrolysis products from PTT materials and was able to open and hydrolyse a cyclic PTT dimer according to RP-HPLC–UV detection. In contrast, the lipase from T. lanuginosus also showed ac...

  3. Methyl-esterified 3-hydroxybutyrate oligomers protect bacteria from hydroxyl radicals.

    Koskimäki, Janne J; Kajula, Marena; Hokkanen, Juho; Ihantola, Emmi-Leena; Kim, Jong H; Hautajärvi, Heidi; Hankala, Elina; Suokas, Marko; Pohjanen, Johanna; Podolich, Olga; Kozyrovska, Natalia; Turpeinen, Ari; Pääkkönen, Mirva; Mattila, Sampo; Campbell, Bruce C; Pirttilä, Anna Maria

    2016-05-01

    Bacteria rely mainly on enzymes, glutathione and other low-molecular weight thiols to overcome oxidative stress. However, hydroxyl radicals are the most cytotoxic reactive oxygen species, and no known enzymatic system exists for their detoxification. We now show that methyl-esterified dimers and trimers of 3-hydroxybutyrate (ME-3HB), produced by bacteria capable of polyhydroxybutyrate biosynthesis, have 3-fold greater hydroxyl radical-scavenging activity than glutathione and 11-fold higher activity than vitamin C or the monomer 3-hydroxybutyric acid. We found that ME-3HB oligomers protect hypersensitive yeast deletion mutants lacking oxidative stress-response genes from hydroxyl radical stress. Our results show that phaC and phaZ, encoding polymerase and depolymerase, respectively, are activated and polyhydroxybutyrate reserves are degraded for production of ME-3HB oligomers in bacteria infecting plant cells and exposed to hydroxyl radical stress. We found that ME-3HB oligomer production is widespread, especially in bacteria adapted to stressful environments. We discuss how ME-3HB oligomers could provide opportunities for numerous applications in human health. PMID:26974813

  4. Elimination of the interfering effects of ascorbic acid in the electrochemical monitoring of bio-active constituents in body fluid samples by using the powder microelectrode technique

    Cha, Chuan-sin; Chen, Jianyong

    2001-09-01

    Interference caused by ascorbic acid has been one of the most frequently encountered problems in the design of amperometric biosensors. The accuracy of the nowadays well- commercialized amperometric blood glucose monitor is still more or less affected by the fluctuation of ascorbic acid level in blood. The interference of ascorbic acid is serious and widespread.

  5. Structure and Oligomers Distribution of Commercial Tara (Caesalpina spinosa Hydrolysable Tannin

    Samuele GIOVANDO

    2013-03-01

    Full Text Available Solvent extracted commercial Tara tanninextract have been examined by Matrix Assisted LaserDesorption/Ionisation Time-of-Flight (MALDI-TOFmass spectrometry and by High Pressure LiquidChromatography (HPLC. The Tara extract has beenfound to be composed of a series of oligomers ofpolygallic acid attached by an ester link to one quinicacid. They constitute the oligomers in higherproportion in the extract. Other polygallic chains linkedto one only or two repeating units such as caffeic acidand methylated quinic, methylated gallic andmethylated caffeic acids are also present. Negativeion mode MALDI-TOF showed that somecarbohydrate residues appear to still be present,linked to the polyphenolic material of the extract buttheir proportion is very low as would be expected of asolvent extracted tannin.

  6. Vibronic Lineshapes of PTCDA Oligomers in Helium Nanodroplets

    Roden, Jan; Eisfeld, Alexander; Dvorak, Matthieu; Buenermann, Oliver; Stienkemeier, Frank

    2010-01-01

    Oligomers of the organic semiconductor PTCDA are studied by means of helium nanodroplet isolation (HENDI) spectroscopy. In contrast to the monomer absorption spectrum, which exhibits clearly separated, very sharp absorption lines, it is found that the oligomer spectrum consists of three main peaks having an apparent width orders of magnitude larger than the width of the monomer lines. Using a simple theoretical model for the oligomer, in which a Frenkel exciton couples to internal vibrational...

  7. Pigments and oligomers for inks - moving towards the best combination

    The formulation of UV curable printing inks depends on several complex factors. If the individual components of the ink are not complementary, then performance problems can arise. One critical combination is that between the pigment and the oligomer. In a new approach to improve understanding of pigment/oligomer interactions, the resources of a pigment manufacturer and an oligomer manufacturer have been combined to investigate the problem. Initial screening of process yellow pigments and several oligomer types highlighted performance variations which were then examined in more detail

  8. Chemical Modifications of Antisense Morpholino Oligomers Enhance Their Efficacy against Ebola Virus Infection▿

    Swenson, Dana L.; Warfield, Kelly L.; Warren, Travis K.; Lovejoy, Candace; Hassinger, Jed N.; Ruthel, Gordon; Blouch, Robert E; Moulton, Hong M; Weller, Dwight D.; Iversen, Patrick L.; Bavari, Sina

    2009-01-01

    Phosphorodiamidate morpholino oligomers (PMOs) are uncharged nucleic acid-like molecules designed to inactivate the expression of specific genes via the antisense-based steric hindrance of mRNA translation. PMOs have been successful at knocking out viral gene expression and replication in the case of acute viral infections in animal models and have been well tolerated in human clinical trials. We propose that antisense PMOs represent a promising class of therapeutic agents that may be useful ...

  9. Mx oligomer: a novel capsid pattern sensor?

    Kong, Jia; Ma, Min; He, Shuangyi; Qin, Xiaohong

    2016-08-01

    Myxovirus resistance proteins represent a family of interferon-induced restriction factors of the innate and adaptive immune system. Human MxB acts as a novel restriction factor with antiviral activity against a range of HIV-1 and other retroviruses mainly by inhibiting the uncoating process after reverse transcription but prior to integration. Based on published data and conservation analysis, we propose a novel hypothesis, in which MxB dimers form higher order oligomers that restrict retroviral replication by binding to the viral capsid. Insights into the mechanistic basis of structural and functional characteristics of MxB will greatly advance our understanding of MxB. PMID:27492442

  10. Macrocyclic 2,7-Anthrylene Oligomers.

    Yamamoto, Yuta; Wakamatsu, Kan; Iwanaga, Tetsuo; Sato, Hiroyasu; Toyota, Shinji

    2016-05-01

    A macrocyclic compound consisting of six 2,7-anthrylene units was successfully synthesized by Ni-mediated coupling of the corresponding dibromo precursor as a novel π-conjugated compound. This compound was sufficiently stable and soluble in organic solvents due to the presence of mesityl groups. X-ray analysis showed that the molecule had a nonplanar and hexagonal wheel-shaped framework of approximately S6 symmetry. The dynamic process between two S6 structures was observed by using the dynamic NMR technique, the barrier being 58 kJ mol(-1) . The spectroscopic properties of the hexamer were compared with those of analogous linear oligomers. PMID:26918910

  11. Anharmonic Vibrational Dynamics of DNA Oligomers

    Kühn, O; Krishnan, G M; Fidder, H; Heyne, K

    2008-01-01

    Combining two-color infared pump-probe spectroscopy and anharmonic force field calculations we characterize the anharmonic coupling patterns between fingerprint modes and the hydrogen-bonded symmetric NH$_2$ stretching vibration in adenine-thymine dA$_{20}$-dT$_{20}$ DNA oligomers. Specifically, it is shown that the anharmonic coupling between the NH$_2$ bending and the CO stretching vibration, both absorbing around 1665 cm-1, can be used to assign the NH$_2$ fundamental transition at 3215 cm-1 despite the broad background absorption of water.

  12. Environmental Factors Preceding Aβ40 Monomer to Oligomers and the Detection of Oligomers in Alzheimer's Disease Patient Serum

    Yoichi Matsunaga; Midori Suenaga

    2012-01-01

    We present here environmental factors including pH shifts, temperature, and metal ions surrounding A β 40 monomer to precede the oligomers. We also suggest a new idea to detect A β 40 oligomers with anti-A β 40 monoclonal antibody using enzyme-linked immunosorbent assay. This method involves the different sensitivity of the thermal shifts between A β 40 monomer and the oligomers. The idea is useful for the diagnostics of Alzheimer's disease to detect A β 40 oligomers in the serum from the pat...

  13. Isolation and Quantification of Polyamide Cyclic Oligomers in Kitchen Utensils and Their Migration into Various Food Simulants.

    Abe, Yutaka; Mutsuga, Motoh; Ohno, Hiroyuki; Kawamura, Yoko; Akiyama, Hiroshi

    2016-01-01

    Small amounts of cyclic monomers and oligomers are present in polyamide (PA)-based kitchen utensils. In this study, we isolated eight PA-based cyclic monomers and oligomers from kitchen utensils made from PA6 (a polymer of ε-caprolactam) and PA66 (a polymer of 1,6-diaminohexane and adipic acid). Their structures were identified using high-resolution mass spectrometry and 1H- and 13C-nuclear magnetic resonance spectroscopy, and their residual levels in PA-based kitchen utensils and degree of migration into food simulants were quantified by high-performance liquid chromatography/mass spectrometry using purchased PA6 monomer and isolated PA66 monomers, and isolated PA6 and PA66 oligomers as calibration standards. Their total residual levels among 23 PA-based kitchen utensils made from PA6, PA66, and copolymers of PA6 and PA66 (PA6/66) ranged from 7.8 to 20 mg/g. Using water, 20% ethanol, and olive oil as food simulants, the total migration levels of the PA monomers and oligomers ranged from 0.66 to 100 μg/cm2 under most examined conditions. However, the total migration levels of the PA66 monomer and oligomers from PA66 and PA6/66 kitchen utensils into 20% ethanol at 95°C were very high (1,700 and 2,200 μg/cm2, respectively) due to swelling by high-temperature ethanol. PMID:27453976

  14. Cooperative Switching in Nanofibers of Azobenzene Oligomers.

    Weber, Christopher; Liebig, Tobias; Gensler, Manuel; Zykov, Anton; Pithan, Linus; Rabe, Jürgen P; Hecht, Stefan; Bléger, David; Kowarik, Stefan

    2016-01-01

    Next-generation molecular devices and machines demand the integration of molecular switches into hierarchical assemblies to amplify the response of the system from the molecular level to the meso- or macro-scale. Here, we demonstrate that multi-azobenzene oligomers can assemble to form robust supramolecular nanofibers in which they can be switched repeatedly between the E- and Z-configuration. While in isolated oligomers the azobenzene units undergo reversible photoisomerization independently, in the nanofibers they are coupled via intermolecular interactions and switch cooperatively as evidenced by unusual thermal and kinetic behavior. We find that the photoisomerization rate from the Z-isomer to the E-isomer depends on the fraction of Z-azobenzene in the nanofibers, and is increased by more than a factor of 4 in Z-rich fibers when compared to E-rich fibers. This demonstrates the great potential of coupling individual photochromic units for increasing their quantum efficiency in the solid state with potential relevance for actuation and sensing. PMID:27161608

  15. Solvent induced track sensitization. Extraction of oligomers

    Apel, P.; Angert, N.; Brüchle, W.; Hermann, H.; Kampschulte, U.; Klein, P.; Kravets, L. I.; Oganessian, Yu. Ts.; Remmert, G.; Spohr, R.; Steckenreiter, T.; Trautmann, C.; Vetter, J.

    1994-04-01

    Oligomer extraction from polyethylene terephthalate (PET) irradiated by xenon ions of 11.4 MeV/u is investigated using UV spectrophotometry and gel permeation chromatography (GPC). The cyclic trimer is identified as the predominant diffusing species removed during extraction by dimethyl formamide (DMF). Extraction dynamics is modeled by a rapid (time constant ≈ 2 min) and a slow (time constant ≈ 100 min) diffusion process attributed to the latent ion tracks and to the virgin material, respectively. Thereby latent tracks act simultaneously as irrigation and drainage pipes for the transfer of the solvent into and the extraction of oligomers from the polymer matrix. Thus tracks help to release osmotic pressure differences and to avoid blistering of the unirradiated polymer during solvent exchange. The total extracted mass per track shows a characteristic decrease with increasing ion fluence interpreted as oxygen effect, due to the decreasing supply of oxygen in the sample during irradiation. The extractable mass corresponds to an equivalent track diameter of initially around 10 nm contracting with increasing ion fluence to an asymptotic value around 3 nm.

  16. Cooperative Switching in Nanofibers of Azobenzene Oligomers

    Weber, Christopher; Liebig, Tobias; Gensler, Manuel; Zykov, Anton; Pithan, Linus; Rabe, Jürgen P.; Hecht, Stefan; Bléger, David; Kowarik, Stefan

    2016-01-01

    Next-generation molecular devices and machines demand the integration of molecular switches into hierarchical assemblies to amplify the response of the system from the molecular level to the meso- or macro-scale. Here, we demonstrate that multi-azobenzene oligomers can assemble to form robust supramolecular nanofibers in which they can be switched repeatedly between the E- and Z-configuration. While in isolated oligomers the azobenzene units undergo reversible photoisomerization independently, in the nanofibers they are coupled via intermolecular interactions and switch cooperatively as evidenced by unusual thermal and kinetic behavior. We find that the photoisomerization rate from the Z-isomer to the E-isomer depends on the fraction of Z-azobenzene in the nanofibers, and is increased by more than a factor of 4 in Z-rich fibers when compared to E-rich fibers. This demonstrates the great potential of coupling individual photochromic units for increasing their quantum efficiency in the solid state with potential relevance for actuation and sensing. PMID:27161608

  17. Chemical constituents from Melaleuca alternifolia (Myrtaceae)

    The first chemical study of non-volatile constituents from the bark and stem of Melaleuca alternifolia (Myrtaceae) led to the isolation and identification of 3,3'-O-dimethylellagic acid (1) and five pentacyclic triterpenes: 2α,3β,23-trihydroxyolean-12-en-28-oic acid (arjunolic acid, 2), 3β-hydroxylup-20(29)-en-27,28-dioic acid (melaleucic acid, 3), betulinic acid (4), betuline (5), 3β-O-acetylurs-12-en-28-oic acid (6), a mixture of fatty acids and esters, and several hydrocarbons. For 2α,3β,23-trihydroxyolean-12-en-28-oic acid (2) and 3β-O-acetylurs-12-en-28-oic acid (6) a first detailed assignment of 1H NMR is presented. (author)

  18. Characterization of oligomers from methylglyoxal under dark conditions: a pathway to produce secondary organic aerosol through cloud processing during nighttime

    F. Yasmeen

    2010-04-01

    Full Text Available Aqueous-phase oligomer formation from methylglyoxal, a major atmospheric photooxidation product, has been investigated in a simulated cloud matrix under dark conditions. The aim of this study was to explore an additional pathway producing secondary organic aerosol (SOA through cloud processes without participation of photochemistry during nighttime. Indeed, atmospheric models still underestimate SOA formation, as field measurements have revealed more SOA than predicted. Soluble oligomers (n = 1–8 formed in the course of acid-catalyzed aldol condensation and acid-catalyzed hydration followed by acetal formation have been detected and characterized by positive and negative ion electrospray ionization mass spectrometry. Aldol condensation proved to be a favorable mechanism under simulated cloud conditions, while hydration/acetal formation was found to strongly depend on the pH of the system and only occurred at a pH<3.5. No evidence was found for formation of organosulfates. The aldol oligomer series starts with a β-hydroxy ketone via aldol condensation, where oligomers are formed by multiple additions of C3H4O2 units (72 Da to the parent β-hydroxy ketone. Ion trap mass spectrometry experiments were performed to structurally characterize the major oligomer species. A mechanistic pathway for the growth of oligomers under cloud conditions and in the absence of UV-light and OH radicals, which could substantially enhance in-cloud SOA yields, is proposed here for the first time.

  19. Vibronic line shapes of PTCDA oligomers in helium nanodroplets.

    Roden, Jan; Eisfeld, Alexander; Dvořák, Matthieu; Bünermann, Oliver; Stienkemeier, Frank

    2011-02-01

    Oligomers of the organic semiconductor 3,4,9,10-perylene-tetracarboxylic-dianhydride, C(24)H(8)O(6) (PTCDA) are studied by means of helium nanodroplet isolation spectroscopy. In contrast to the monomer absorption spectrum, which exhibits clearly separated, very sharp absorption lines, it is found that the oligomer spectrum consists of three main peaks having an apparent width orders of magnitude larger than the width of the monomer lines. Using a simple theoretical model for the oligomer, in which a Frenkel exciton couples to internal vibrational modes of the monomers, these experimental findings are nicely reproduced. The three peaks present in the oligomer spectrum can already be obtained taking only one effective vibrational mode of the PTCDA molecule into account. The inclusion of more vibrational modes leads to quasicontinuous spectra, resembling the broad oligomer spectra. PMID:21303160

  20. Statistical mechanics of thermal denaturation of DNA oligomers

    Navin Singh; Yashwant Singh

    2003-08-01

    Double stranded DNA chain is known to have non-trivial elasticity. We study the effect of this elasticity on the denaturation profile of DNA oligomer by constraining one base pair at one end of the oligomer to remain in unstretched (or intact) state. The effect of this constraint on the denaturation profile of the oligomer has been calculated using the Peyrard–Bishop Hamiltonian. The denaturation profile is found to be very different from the free (i.e. without the constraint) oligomer. We have also examined how this constraint affects the denaturation profile of the oligomer having a segment of defect sites located at different parts of the chain.

  1. Properties of Surface Cyclic Oligomers Present on Polyester Fiber

    郑敏; 宋心远

    2003-01-01

    The effects of different treatments, such as dry heat,wet heat, solvent vapor and ultrasonic, on properties of the cyclic oligomers on the surface of polyester fiber are studied. The components of surface oligomers are analyzed through Thin-Layer Chromatograph. The result shows that: all of the treatments, especially solvent vapor treatment, can significantly increase the content of surface cyclic oligomers. The content of cyclic trimer is increased more considerably than other oligomers. Moreover, the morphology and the distribution of surface cyclic oligomers are also different from different treatments: Dry heat and wet heat cause larger polygonal solids distributed evenly on the surface of fiber; solvent vapor makes fiber surface exhibit irregular rodlike crystal shapes randomly; ultrasonic treatment induces some obscure and smaller deposits on the surface of fiber.

  2. Atomic View of a Toxic Amyloid Small Oligomer

    Laganowsky, Arthur; Liu, Cong; Sawaya, Michael R.; Whitelegge, Julian P.; Park, Jiyong; Zhao, Minglei; Pensalfini, Anna; Soriaga, Angela B.; Landau, Meytal; Teng, Poh K.; Cascio, Duilio; Glabe, Charles; Eisenberg, David (UCI); (UCLA)

    2012-04-30

    Amyloid diseases, including Alzheimer's, Parkinson's, and the prion conditions, are each associated with a particular protein in fibrillar form. These amyloid fibrils were long suspected to be the disease agents, but evidence suggests that smaller, often transient and polymorphic oligomers are the toxic entities. Here, we identify a segment of the amyloid-forming protein {alpha}{beta} crystallin, which forms an oligomeric complex exhibiting properties of other amyloid oligomers: {beta}-sheet-rich structure, cytotoxicity, and recognition by an oligomer-specific antibody. The x-ray-derived atomic structure of the oligomer reveals a cylindrical barrel, formed from six antiparallel protein strands, that we term a cylindrin. The cylindrin structure is compatible with a sequence segment from the {beta}-amyloid protein of Alzheimer's disease. Cylindrins offer models for the hitherto elusive structures of amyloid oligomers.

  3. Characterization of non-photochemically formed oligomers from methylglyoxal: a pathway to produce secondary organic aerosol through cloud processing during night-time

    F. Yasmeen

    2009-10-01

    Full Text Available Aqueous-phase oligomer formation from methylglyoxal, a major atmospheric photooxidation product, has been investigated in a simulated cloud matrix under dark conditions. The aim of this study was to explore an additional path producing secondary organic aerosol (SOA through cloud processes without photochemistry during night-time. Indeed, atmospheric models still underestimate SOA formation, as field measurements have revealed more SOA than predicted. Soluble oligomers (n=1–8 formed in the course of acid-catalyzed aldol condensation and acid-catalyzed hydration followed by acetal formation have been detected and characterized by positive and negative ion electrospray ionization mass spectrometry. Aldol condensation proved to be a favorable mechanism under simulated cloud conditions, while hydration/acetal formation was found to strongly depend on the pH of the system. The aldol oligomer series starts with a β-hydroxy ketone via aldol condensation, where oligomers are formed by multiple additions of C3H4O2 units (72 Da to the parent β-hydroxy ketone. Ion trap mass spectrometry experiments were performed to structurally characterize the major oligomer species. A mechanistic pathway for the growth of oligomers under cloud conditions and in the absence of UV-light and OH radicals, which could substantially enhance in-cloud SOA yields, is proposed here for the first time.

  4. Characterization of non-photochemically formed oligomers from methylglyoxal: a pathway to produce secondary organic aerosol through cloud processing during night-time

    Yasmeen, F.; Sauret, N.; Gal, J. F.; Maria, P.-C.; Massi, L.; Maenhaut, W.; Claeys, M.

    2009-10-01

    Aqueous-phase oligomer formation from methylglyoxal, a major atmospheric photooxidation product, has been investigated in a simulated cloud matrix under dark conditions. The aim of this study was to explore an additional path producing secondary organic aerosol (SOA) through cloud processes without photochemistry during night-time. Indeed, atmospheric models still underestimate SOA formation, as field measurements have revealed more SOA than predicted. Soluble oligomers (n=1-8) formed in the course of acid-catalyzed aldol condensation and acid-catalyzed hydration followed by acetal formation have been detected and characterized by positive and negative ion electrospray ionization mass spectrometry. Aldol condensation proved to be a favorable mechanism under simulated cloud conditions, while hydration/acetal formation was found to strongly depend on the pH of the system. The aldol oligomer series starts with a β-hydroxy ketone via aldol condensation, where oligomers are formed by multiple additions of C3H4O2 units (72 Da) to the parent β-hydroxy ketone. Ion trap mass spectrometry experiments were performed to structurally characterize the major oligomer species. A mechanistic pathway for the growth of oligomers under cloud conditions and in the absence of UV-light and OH radicals, which could substantially enhance in-cloud SOA yields, is proposed here for the first time.

  5. New strategy for stable-isotope-aided, multidimensional NMR spectroscopy of DNA oligomers

    Ono, Okira; Tate, Shin-Ichi; Kainosho, Masatsune [Tokyo Metropolitan Univ., Tokyo (Japan)

    1994-12-01

    Nuclear Magnetic Resonance (NMR) is the most efficient method for determining the solution structures of biomolecules. By applying multidimensional heteronuclear NMR techniques to {sup 13}C/{sup 15}N-labeled proteins, we can determine the solution structures of proteins with molecular mass of 20 to 30kDa at an accuracy similar to that of x-ray crystallography. Improvements in NMR instrumentation and techniques as well as the development of protein engineering methods for labeling proteins have rapidly advanced multidimensional heteronuclear NMR of proteins. In contrast, multidimensional heteronuclear NMR studies of nucleic acids is less advanced because there were no efficient methods for preparing large amounts of labeled DNA/RNA oligomers. In this report, we focused on the chemical synthesis of DNA oligomers labeled at specific residue(s). RNA oligomers with specific labels, which are difficult to synthesize by the enzyme method, can be synthesized by the chemical method. The specific labels are useful for conformational analysis of larger molecules such as protein-nucleic acid complexes.

  6. New strategy for stable-isotope-aided, multidimensional NMR spectroscopy of DNA oligomers

    Nuclear Magnetic Resonance (NMR) is the most efficient method for determining the solution structures of biomolecules. By applying multidimensional heteronuclear NMR techniques to 13C/15N-labeled proteins, we can determine the solution structures of proteins with molecular mass of 20 to 30kDa at an accuracy similar to that of x-ray crystallography. Improvements in NMR instrumentation and techniques as well as the development of protein engineering methods for labeling proteins have rapidly advanced multidimensional heteronuclear NMR of proteins. In contrast, multidimensional heteronuclear NMR studies of nucleic acids is less advanced because there were no efficient methods for preparing large amounts of labeled DNA/RNA oligomers. In this report, we focused on the chemical synthesis of DNA oligomers labeled at specific residue(s). RNA oligomers with specific labels, which are difficult to synthesize by the enzyme method, can be synthesized by the chemical method. The specific labels are useful for conformational analysis of larger molecules such as protein-nucleic acid complexes

  7. Enzymatic hydrolysis of PTT polymers and oligomers.

    Eberl, A; Heumann, S; Kotek, R; Kaufmann, F; Mitsche, S; Cavaco-Paulo, A; Gübitz, G M

    2008-05-20

    Oligomers and polymers (film, fabrics) of the linear aromatic polyester poly(trimethylene terephthalate) (PTT) were treated with polyesterases from Thermomyces lanuginosus, Penicillium citrinum, Thermobifida fusca and Fusarium solani pisi. The cutinase from T. fusca was found to release the highest amounts of hydrolysis products from PTT materials and was able to open and hydrolyse a cyclic PTT dimer according to RP-HPLC-UV detection. In contrast, the lipase from T. lanuginosus also showed activity on the PTT fibres and on bis(3-hydroxypropyl) terephthalate (BHPT) but was not able to hydrolyse the polymer film, mono(3-hydroxypropyl) terephthalate (MHPT) nor the cyclic dimer of PTT. As control enzymes inhibited with mercury chloride were used. Surface hydrophilicity changes were investigated with contact angle measurements and the degree of crystallinity changes were determined with DSC. PMID:18405994

  8. Formation of secondary organic aerosol and oligomers from the ozonolysis of enol ethers

    Sadezky, A.; Chaimbault, P.; Mellouki, A.; Römpp, A.; Winterhalter, R.; Le Bras, G.; Moortgat, G. K.

    2006-10-01

    Formation of secondary organic aerosol has been observed in the gas phase ozonolysis of a series of enol ethers, among them several alkyl vinyl ethers (AVE, ROCH=CH2), such as ethyl, propyl, n-butyl, iso-butyl, t-butyl vinyl ether, and ethyl propenyl ether (EPE, C2H5OCH=CHCH3). The ozonolysis has been studied in a 570 l spherical glass reactor at ambient pressure (730 Torr) and room temperature (296 K). Gas phase reaction products were investigated by in-situ FTIR spectroscopy, and secondary organic aerosol (SOA) formation was monitored by a scanning mobility particle sizer (SMPS). The chemical composition of the formed SOA was analysed by a hybrid mass spectrometer using electrospray ionization (ESI). The main stable gas phase reaction product is the respective alkyl formate ROC(O)H, formed with yields of 60 to 80%, implying that similar yields of the corresponding excited Criegee Intermediates (CI) CH2O2 for the AVE and CH3CHO2 for EPE are generated. Measured SOA yields are between 2 to 4% for all enol ethers. Furthermore, SOA formation is strongly reduced or suppressed by the presence of an excess of formic acid, which acts as an efficient CI scavenger. Chemical analysis of the formed SOA by ESI(+)/MS-TOF allows to identify oligomeric compounds in the mass range 200 to 800 u as its major constituents. Repetitive chain units are identified as CH2O2 (mass 46) for the AVE and C2H4O2 (mass 60) for EPE and thus have the same chemical compositions as the respective major Criegee Intermediates formed during ozonolysis of these ethers. The oligomeric structure and chain unit identity are confirmed by HPLC/ESI(+)/MS-TOF and ESI(+)/MS/MS-TOF experiments, whereby successive and systematic loss of a fragment with mass 46 for the AVE (and mass 60 for EPE) is observed. It is proposed that the oligomer has the following basic structure of an oligoperoxide, -[CH(R)-O-O]n-, where R=H for the AVE and R=CH3 for the EPE. Oligoperoxide formation is thus suggested to be another, so

  9. Determination of the content of rosmarinic acid by HPLC and analytical comparison of volatile constituents by GC-MS in different parts of Perilla frutescens (L.) Britt

    Liu, Jing; Wan, Yuklam; Zhao, Zhongzhen; Chen, Hubiao

    2013-01-01

    Background Perilla frutescens (L.) Britt. is not only an edible plant but also a traditional medicinal plant commonly used for treating common cold. It is widely cultivated in southern China. The anatomical parts of P. frutescens that are recorded as medicines in the Chinese material medica are: Perillae Caulis, Perillae Folium and Perillae Fructus, which are the dried stems, the dried leaves and the dried ripe fruits, respectively. Rosmarinic acid is one of major polyphenolic ingredients fou...

  10. Polymerization on the rocks: negatively-charged alpha-amino acids

    Hill, A. R. Jr; Bohler, C.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    Oligomers of the negatively-charged amino acids, glutamic acid, aspartic acid, and O-phospho-L-serine are adsorbed by hydroxylapatite and illite with affinities that increase with oligomer length. In the case of oligo-glutamic acids adsorbed on hydroxylapatite, addition of an extra residue results in an approximately four-fold increase in the strength of adsorption. Oligomers much longer than the 7-mer are retained tenaciously by the mineral. Repeated incubation of short oligo-glutamic acids adsorbed on hydroxylapatite or illite with activated monomer leads to the accumulation of oligomers at least 45 units long. The corresponding reactions of aspartic acid and O-phospho-L-serine on hydroxylapatite are less effective in generating long oligomers, while illite fails to accumulate substantial amounts of long oligomers of aspartic acid or of O-phospho-L-serine.

  11. Constituents of Chondria armata

    Govenkar, M.B.; Wahidullah, S.

    A novel long chain fatty ester, pentyl hentriacontanoate 1 and an orange red pigment, caulerpin 2 have been isolated and characterised from a red alga Chondria armata. The pigment caulerpin hitherto known to be a constituent of green algae of genus...

  12. Quantifier Scope and Constituency

    Park, J C

    1995-01-01

    Traditional approaches to quantifier scope typically need stipulation to exclude readings that are unavailable to human understanders. This paper shows that quantifier scope phenomena can be precisely characterized by a semantic representation constrained by surface constituency, if the distinction between referential and quantificational NPs is properly observed. A CCG implementation is described and compared to other approaches.

  13. Thermodynamics of Constituent Quarks

    Pirner, H. J.; Wachs, M

    1997-01-01

    We investigate the thermal behavior of quarks and antiquarks interacting via a temperature-dependent linear potential. The quarks are constituent quarks with dynamically generated masses from the background linear $\\sigma$-model.We find a transition from a system of bound mesons to a correlated quark gas at the same temperature as the chiral transition temperature.

  14. Isoflavone and Protein Constituents of Lactic Acid-Fermented Soy Milk Combine to Prevent Dyslipidemia in Rats Fed a High Cholesterol Diet

    Maki Kobayashi; Shintaro Egusa; Mitsuru Fukuda

    2014-01-01

    A high cholesterol diet induces dyslipidemia. This study investigated whether isoflavone aglycones in lactic acid-fermented soy milk (LFS) improve lipid metabolism in rats fed a high cholesterol diet. Male Sprague-Dawley rats aged seven weeks were fed an AIN-93G diet, a 1% cholesterol diet (a high cholesterol diet), a high-cholesterol diet containing 4% isoflavone extract of LFS (LFS extract diet), a high-cholesterol diet containing 19.4% ethanol-washed LFS (ethanol-washed LFS diet, isoflavon...

  15. Acid rain effect in the constituent material of Mexican Mayan monuments; Efecto de la lluvia acida en el material constituyente de los monumentos Mayas mexicanos

    Bravo Alvarez, H.; Soto Ayala, R.; Sosa Echeverria, R.; Sanchez Alvarez, P. [Facultad de Ingenieria, UNAM, Mexico, D.F. (Mexico)

    2003-12-01

    Actually, acid rain is considered as a potential problem that affects materials and ecosystems. The effect on monuments, made mainly from limestone, has been studied for long time. In this work, a sample of limestone from Tulum, Quintana Roo, was studied. The following parameters were measured: density, porosity and percentage of water adsorption. Also, the sample was irrigated with acid rain prepared in the laboratory (pH 4.6), based in the chemical composition of 56 rain samples from Puerto Morelos, Quintana Roo, in 1994 and 1995. The results obtained show that acid rain is neutralized by calcium carbonate from the limestone. The high calcium concentrations in the effluent show that limestone is dissolved by acid rain. Superficial recession was 4.4 {mu}m/year under experimental conditions used. [Spanish] Actualmente la lluvia acida se ha convertido en un problema potencial que afecta en mayor o menor grado a materiales y a los ecosistemas. El efecto que causa la lluvia acida en monumentos construidos fundamentalmente de roca caliza, ha sido objeto de muchas investigaciones realizadas, prioritariamente, por paises que poseen estructuras, cuyo material de construccion es caliza. En este trabajo de investigacion se estudio una muestra de roca caliza proveniente de los monumentos mayas de Tulum, Quintana Roo. Se determinaron los parametros de densidad, porosidad y porcentaje de adsorcion de agua. Asimismo, se efectuo la irrigacion de la muestra con lluvia acida (pH aprox. 4.6), preparada en el laboratorio con base en la composicion quimica que se determino en 56 muestras de agua de lluvia provenientes de Puerto Morelos, punto cercano a los monumentos de Tulum, Quintana Roo, durante los anos 1994 y 1995. Los resultados permiten concluir que la lluvia acida sufre un proceso de neutralizacion con el carbonato de calcio de la roca caliza. Las altas concentraciones de calcio en el efluente, mostraron que la roca caliza sufrio una disolucion con la lluvia acida. La

  16. Effect of the acid rain in the constituent material of the Mayan Mexican monuments; Efecto de la lluvia acida en el material constituyente de los monuments mayas mexicanos

    Bravo Alvarez, H; Soto Ayala, R; Sosa Echeverria, R; Sanchez Alvarez, P [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2003-10-15

    Actually, acid rain is considered as a potential problem that affects materials and ecosystems. The effect on monuments, made mainly from limestone, has been studied for long time. In this work, a sample of limestone from Tulum, Qintana Roo, was studied. The following parameters were measured: density, porosity and percentage of water adsorption. Also, the sample was irrigated with acid rain prepared in the laboratory (pH = 4.6), based in the chemical composition of 56 rain samples from Puerto Morelos, Quintana Roo, in 1994 and 1995. The results obtained show that acid rain is neutralized by calcium carbonate from the limestone. The high calcium concentrations in the effluent, show that limestone is dissolved by acid rain. Superficial recession was 4.4 {mu}m/year under experimental conditions used. [Spanish] Actualmente la lluvia acida se ha convertido en un problema potencial que afecta en mayor o menor grado a materiales y a los ecosistemas. El efecto que causa la lluvia acida en monumentos construidos fundamentalmente de roca caliza, ha sido objeto de muchas investigaciones realizadas, prioritariamente, por paises que poseen estructuras, cuyo material de construccion es caliza. En este trabajo de investigacion se estudio una muestra de roca caliza proveniente de los monumentos mayas de Tulum, Quintana Roo. Se determinaron los parametros de densidad, porosidad y porcentaje de adsorcion de agua. Asimismo, se efectuo la irrigacion de la muestra con lluvia acida (pH aprox.4.6), preparada en el laboratorio con base en la composicion quimica que se determino en 56 muestras de agua de lluvia provenientes de Puerto Morelos, punto cercano a los monumentos de Tulum, Quintana Roo, durante los anos 1994 y 1995. Los resultados permiten concluir que la lluvia acida sufre un proceso de naturalizacion con el carbonato de calcio de la roca caliza. Las altas concentraciones de calcio en el efluente, mostraron que la roca caliza sufrio una disolucion con la lluvia acida. La

  17. A new source of oxygenated organic aerosol and oligomers

    J. Liggio

    2013-03-01

    Full Text Available A large oxygenated organic uptake to aerosols was observed when exposing ambient urban air to inorganic acidic and non-acidic sulfate seed aerosol. For non-acidic seed aerosol the uptake was attributed to the direct dissolution of primary vehicle exhaust gases into the aqueous aerosol fraction, and was correlated to the initial seed sulphate mass. The uptake of primary oxygenated organic gases to aerosols in this study represents a significant amount of organic aerosol (OA that may be considered primary when compared to that reported for primary organic aerosol (POA, but is considerably more oxygenated (O : C ~ 0.3 than traditional POA. Consequently, a fraction of measured ambient oxygenated OA, which correlates with secondary sulphate, may in fact be of a primary, rather than secondary source. These results represent a new source of oxygenated OA on neutral aerosol and imply that the uptake of primary organic gases will occur in the ambient atmosphere, under dilute conditions, and in the presence of pre-existing SO4 aerosols which contain water. Conversely, under acidic seed aerosol conditions, oligomer formation was observed with the uptake of organics being enhanced by a factor of three or more compared to neutral aerosols, and in less than 2 min, representing an additional source of SOA to the atmosphere. This resulted in a trajectory in Van Krevelen space towards higher O : C (slope ~ −1.5, despite a lack of continual gas-phase oxidation in this closed system. The results demonstrate that high molecular weight species will form on acidic aerosols at the ambient level and mixture of organic gases, but are otherwise unaffected by subsequent aerosol neutralization, and that aerosol acidity will affect the organic O : C via aerosol-phase reactions. These two processes, forming oxygenated POA under neutral conditions and SOA under acidic conditions can contribute to the total ambient OA mass and the evolution of ambient aerosol O : C ratios

  18. Atomistic simulation of CO 2 solubility in poly(ethylene oxide) oligomers

    Hong, Bingbing

    2013-10-02

    We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide) dimethyl ether, CH3O(CH 2CH2O)nCH3 (PEO for short) is a widely applied physical solvent that forms the major organic constituent of a class of novel nanoparticle-based absorbents. Good predictions were obtained for pressure-composition-density relations for CO2 + PEO oligomers (2 ≤ n ≤ 12), using the Potoff force field for PEO [J. Chem. Phys. 136, 044514 (2012)] together with the TraPPE model for CO2 [AIChE J. 47, 1676 (2001)]. Water effects on Henrys constant of CO2 in PEO have also been investigated. Addition of modest amounts of water in PEO produces a relatively small increase in Henrys constant. Dependence of the calculated Henrys constant on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length. © 2013 Taylor & Francis.

  19. Influence of soil phenolic constituents on plant uptake of 32P-labelled phosphate from an acid tea soil of Sri Lanka

    Phenols are believed to play a dominant role in the formation and composition of humus, a subject of fundamental importance to soil productivity. In the present study, greenhouse techniques were used to examine the comparative effects of phenol-rich and non-phenolic plant residues as soil amendments on uptake of 32P-labelled phosphate from a high P-fixing acid soil. The results indicate that: (i) incorporation of phenol-rich plant residues increases 'soil phenolic content'; (ii) this increase in soil phenolic content does not result in a corresponding decrease in P fixation capacity or an increase in plant uptake of labelled P; (iii) plant residues having low degradability are more effective in decreasing P fixation capacity of soil and thus increasing plant uptake of labelled P. (author)

  20. Organic heterostructures based on arylenevinylene oligomers deposited by MAPLE

    Socol, M.; Preda, N.; Vacareanu, L.; Grigoras, M.; Socol, G.; Mihailescu, I. N.; Stanculescu, F.; Jelínek, Miroslav; Stanculescu, A.; Stoicanescu, M.

    2014-01-01

    Roč. 302, May (2014), s. 216-222. ISSN 0169-4332 Institutional support: RVO:68378271 Keywords : organic heterostructures * MAPLE * oligomer * optoelectronica Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.711, year: 2014

  1. Revisting the physics of Fano resonances for nanoparticle oligomers

    Hopkins, Ben; Miroshnichenko, Andrey E; Kivshar, Yuri S

    2013-01-01

    We present a new and robust approach for interpreting the physics of Fano resonances in both metallic and dielectric oligomer nanostructures. A key mechanism for Fano resonances is revealed by demonstrating that Fano resonances can be generated purely from the interference of non-orthogonal collective eigenmodes, which are clearly identified based on the coupled-dipole approximation. We prove analytically a general theorem to identify the number of collective eigenmodes that can be excited in ring-type nanoparticle oligomers and further demonstrate that no dark mode excitation is necessary for existence of Fano resonances in symmetric oligomers. As a consequence, we unify the understanding of Fano resonances for both plasmonic and all-dielectric oligomers.

  2. 聚丙烯酸类浆料组分设计分析及命名建议%Constituent Design Analyses and Naming Suggestion on Polyacrylic Acid Size

    洪仲秋

    2001-01-01

    阐述了设计聚丙烯酸类浆料应根据四种主要组分——单体、乳化剂、引发剂和分散介质的主 要性质以及对聚合物性能的影响进行优选;针对国内聚丙烯酸类浆料命名不统一的现状,提 出了规范命名的具体建议,并根据纺织产品的发展动态指出了开发新型浆料的方向。%The viewpoint in designing polyacrylic acid size was elaborated like that the design should be optimized by the main performance and the influence on the polymer of four important constituents such as monomer,emul sifier,initiator and dispersion medium.In view the statusquo of the uncentrali zation on naming polyacrylic acid size in nation,the practical suggestion on sta ndarding the naming was pointed out,and the direction on developing new size was pointed out by the development tendency of textile products.

  3. [Constituents of the leaves of Ligustrum delavayanum Hariot].

    Nagy, M; Baróniková, S; Grancai, D; Mucaji, P

    2001-11-01

    From the chloroform part of Ligustrum delavayanum Hariot, leaves five constituents were isolated: tyrosol, esculetine, kempferol-7-O-rhamnoside, quercetine-3-O-glucoside, and quercetine. Further six constituents (probably malvidine, two secoiridoid glycosides, caffeic acid monosaccharide ester, quercetine monoglycoside (no hyperoside), and quercetine diglycoside (no rutinoside)) were isolated from the methanolic part of above mentioned drug. PMID:11797198

  4. Inorganic Constituents in Coal

    Rađenović A.

    2006-02-01

    Full Text Available Coal contains not only organic matter but also small amounts of inorganic constituents. More thanone hundred different minerals and virtually every element in the periodic table have been foundin coal. Commonly found group minerals in coal are: major (quartz, pyrite, clays and carbonates,minor, and trace minerals. Coal includes a lot of elements of low mass fraction of the orderof w=0.01 or 0.001 %. They are trace elements connected with organic matter or minerals comprisedin coal. The fractions of trace elements usually decrease when the rank of coal increases.Fractions of the inorganic elements are different, depending on the coal bed and basin. A varietyof analytical methods and techniques can be used to determine the mass fractions, mode ofoccurrence, and distribution of organic constituents in coal. There are many different instrumentalmethods for analysis of coal and coal products but atomic absorption spectroscopy – AAS is theone most commonly used. Fraction and mode of occurrence are one of the main factors that haveinfluence on transformation and separation of inorganic constituents during coal conversion.Coal, as an important world energy source and component for non-fuels usage, will be continuouslyand widely used in the future due to its relatively abundant reserves. However, there is aconflict between the requirements for increased use of coal on the one hand and less pollution onthe other. It’s known that the environmental impacts, due to either coal mining or coal usage, canbe: air, water and land pollution. Although, minor components, inorganic constituents can exert asignificant influence on the economic value, utilization, and environmental impact of the coal.

  5. Inorganic Constituents in Coal

    Rađenović A.

    2006-01-01

    Coal contains not only organic matter but also small amounts of inorganic constituents. More thanone hundred different minerals and virtually every element in the periodic table have been foundin coal. Commonly found group minerals in coal are: major (quartz, pyrite, clays and carbonates),minor, and trace minerals. Coal includes a lot of elements of low mass fraction of the orderof w=0.01 or 0.001 %. They are trace elements connected with organic matter or minerals comprisedin coal. The fract...

  6. Chemical constituents of Asparagus

    J S Negi

    2010-01-01

    Full Text Available Asparagus species (family Liliaceae are medicinal plants of temperate Himalayas. They possess a variety of biological properties, such as being antioxidants, immunostimulants, anti-inflammatory, antihepatotoxic, antibacterial, antioxytocic, and reproductive agents. The article briefly reviews the isolated chemical constituents and the biological activities of the plant species. The structural formula of isolated compounds and their distribution in the species studied are also given.

  7. Beer constituents as potential cancer chemopreventive agents.

    Gerhäuser, Clarissa

    2005-09-01

    Beer is a complex alcoholic beverage made from barley (malt), hop, water and yeast. Phenolic constituents of beer are derived from malt (70-80%) and hop (20-30%). Structural classes include simple phenols, benzoic- and cinnamic acid derivatives, coumarins, catechins, di-, tri- and oligomeric proanthocyanidins, (prenylated) chalcones and flavonoids as well as alpha- and iso-alpha-acids derived from hop. Compounds belonging to different structural classes have distinct profiles of biological activity in in vitro test systems, and in combination might lead to enhanced effects. Scientific evidence has accumulated over the past 10 years pointing to the cancer preventive potential of selected hop-derived beer constituents, i.e., prenylflavonoids including xanthohumol and isoxanthohumol, and hop bitter acids. Chemopreventive activities observed with these compounds relevant to inhibition of carcinogenesis at the initiation, promotion and progression phases, as well as results from in vivo studies on metabolism, bioavailability and efficacy are summarised in this review. PMID:15953717

  8. The effect of polar end of long-chain fluorocarbon oligomers in promoting the superamphiphobic property over multi-scale rough Al alloy surfaces

    Saifaldeen, Zubayda S.; Khedir, Khedir R.; Camci, Merve T.; Ucar, Ahmet; Suzer, Sefik; Karabacak, Tansel

    2016-08-01

    Rough structures with re-entrant property and their subsequent surface energy reduction with long-chain fluorocarbon oligomers are both critical in developing superamphiphobic (SAP, i.e. both super hydrophobic and superoleophobic) surfaces. However, morphology of the low-surface energy layer on a rough re-entrant substrate can strongly depend on the fluorocarbon oligomers used. In this study, the effect of polar end of different kinds of long-chain fluorocarbon oligomers in promoting a self-assembled monolayer with close packed molecules and robust adhesion on multi-scale rough Al alloy surfaces was investigated. Hierarchical Al alloy surfaces with microgrooves and nanograss structures were developed by a simple combination of one-directional mechanical sanding and post treatment in boiling de-ionized water (DIW). Three types of long-chain fluorocarbon oligomers of 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDTS), 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFDCS), and perfluorooctanoic acid (PFOA) were chemically vaporized onto these rough Al alloy surfaces. The PFDCS exhibited the lowest surface free energy of less than 10 mN/m. The contact angle and sliding angle measurements for water, ethylene glycol, and peanut oil verified the SAP property of hierarchical rough Al alloy surfaces treated with alkylsilane oligomers (PFDTS, PFDCS). However, the hierarchical surfaces treated with fluorocarbon oligomer with polar acidic tail (PFOA) showed highly amphiphobic properties but could not reach the threshold for SAP. Chemical stability of the hierarchical Al alloy surfaces treated with the fluorocarbon oligomers was tested under the harsh conditions of ultra-sonication in acetone and annealing at high temperature after different treatment times. Contact angle measurements revealed the robustness of the alkylsilane oligomers and deterioration of the PFOA coating particularly for low surface tension liquids. The robust adhesion and close-packing of the alkylsilane

  9. [Chemical constituents from Cinnamomum cassia].

    He, Shan; Jiang, Yong; Tu, Peng-fei

    2015-09-01

    Various column chromatography, such as silica gel, Sephadex LH-20, ODS, and semi-preparative HPLC was used to isolate and purify the chemical constituents from Cinnamomum cassia. The structures were determined on the basis of NMR and MS spectral data analysis, together with the comparison with literature data. Fifteen compounds were isolated from the 85% aqueous ethanol extract of C. cassia, and their structures were identified as (2R, 3R)-5,7,3',4'-tetramethoxyflavan-3-ol( 1), (2R, 3R)-5,7-dimethoxy-3',4'-methylenedioxyflavan-3-ol (2), coumarin (3), cinnamic acid (4), (E)-2-hydroxy-phenylpropionic acid cinnamoyl ester (5), 3, 3', 4, 4'-tetrahydroxy biphenyl (6), methylstictic acid (7), epi-boscialin (8), (1R,2S,3S,4S)-2,3-epoxy-1, 4-dihydroxy-5-methyl-5-cyelohexene (9), 4,5-dihydroxy-3-methyl cyclohex-2-enone (10), cis-4-hydroxymellein (11), and 2-hydroxy-4-methoxyl-cinnamaldehyde (12). Compounds 5-11 were obtained from this genus plants for the first time. PMID:26983207

  10. Chemical constituents of Saniculiphyllum guangxiense.

    Geng, Chang-An; Huang, Xiao-Yan; Lei, Li-Gong; Zhang, Xue-Mei; Chen, Ji-Jun

    2012-08-01

    The first phytochemical investigation on Saniculiphyllum guangxiense resulted in the isolation of two new triterpenoids, 16β-hydroxybryodulcosigenin (3) and 3α-O-feruloylolean-12-en-27-oic acid (6), together with six known compounds, menisdaurin (1), purshianin (2), oleanolic acid (4), 3β-hydroxyolean-12-en-27-oic acid (5), β-sitosterol (7), and daucosterol (8), which were characterized by extensive spectroscopic analyses and in one case by X-ray diffraction. According to this primary investigation, S. guangxiense is rich in nitrile glucosides and triterpenoids, of which menisdaurin (1; 0.06%) and purshianin (2; 0.015%) are the main constituents. Compounds 1-6 were assayed for their anti-hepatitis B virus (HBV) activities against the secretion of HBsAg and HBeAg, as well as HBV DNA replication on Hep G 2.2.15 cell line in vitro. The most active compound, menisdaurin (1), inhibits HBV DNA replication with an IC(50) value of 0.32 mM (SI>11.97). PMID:22899611

  11. Optimizing antisense oligonucleotides using phosphorodiamidate morpholino oligomers.

    Popplewell, Linda J; Malerba, Alberto; Dickson, George

    2012-01-01

    Duchenne muscular dystrophy (DMD) is caused by mutations that disrupt the reading frame of the human DMD gene. Selective removal of exons flanking an out-of-frame DMD mutation can result in an in-frame mRNA transcript that may be translated into an internally deleted Becker muscular dystrophy-like functionally active dystrophin protein with therapeutic activity. Antisense oligonucleotides (AOs) can be designed to bind to complementary sequences in the targeted mRNA and modify pre-mRNA splicing to correct the reading frame of a mutated transcript. AO-induced exon skipping resulting in functional truncated dystrophin has been demonstrated in animal models of DMD both in vitro and in vivo, in DMD patient cells in vitro in culture, and in DMD muscle explants. The recent advances made in this field suggest that it is likely that AO-induced exon skipping will be the first gene therapy for DMD to reach the clinic. However, it should be noted that personalized molecular medicine may be necessary, since the various reading frame-disrupting mutations are spread across the DMD gene. The different deletions that cause DMD would require skipping of different exons, which would require the optimization and clinical trial workup of many specific AOs. This chapter describes the methodologies available for the optimization of AOs, in particular phosphorodiamidate morpholino oligomers, for the targeted skipping of specific exons on the DMD gene. PMID:22454060

  12. Biophysical characterization data on Aβ soluble oligomers produced through a method enabling prolonged oligomer stability and biological buffer conditions

    Amanda C. Crisostomo

    2015-09-01

    Aβ1-40 soluble oligomers are produced that are suitable for biophysical studies requiring sufficient transient stability to exist in their “native” conformation in biological phosphate-saline buffers for extended periods of time. The production involves an initial preparation of highly monomeric Aβ in a phosphate saline buffer that transitions to fibrils and oligomers through time incubation alone, without added detergents or non-aqueous chemicals. This criteria ensures that the only difference between initial monomeric Aβ reactant and subsequent Aβ oligomer products is their degree of peptide assembly. A number of chemical and biophysical methods were used to characterize the monomeric reactants and soluble oligomer and amyloid fibril products, including chemical cross-linking, Western blots, fraction solubility, thioflvain T binding, size exclusion chromatography, transmission electron micrscopy, circular dichroism spectroscopy, and fluorescence resonance energy transfer.

  13. Conversion of the common food constituent 5-hydroxymethylfurfural into a mutagenic and carcinogenic sulfuric acid ester in the mouse in vivo.

    Monien, Bernhard H; Frank, Heinz; Seidel, Albrecht; Glatt, Hansruedi

    2009-06-01

    5-Hydroxymethylfurfural (HMF), formed by acid-catalyzed dehydration and in the Maillard reaction from reducing sugars, is found at high levels in numerous foods. It was shown to initiate colon aberrant crypt foci in rats and skin papillomas and hepatocellular adenomas in mice. HMF is inactive in in vitro genotoxicity tests using standard activating systems but is activated to a mutagen by sulfotransferases. The product, 5-sulfoxymethylfurfural (SMF), is a stronger carcinogen than HMF. SMF has not been detected in the biotransfomation experiments conducted on HMF in humans and animals in vivo up to date. Here, we report pharmacokinetic properties of HMF and SMF in FVB/N mice. Sensitive assays for the quantification of HMF and SMF by LC-MS/MS multiple reaction monitoring were devised. SMF, intravenously injected (4.4 micromol/kg body mass), showed first-order elimination kinetics in blood plasma (t(1/2) = 7.9 min). HMF, injected intravenously (793 micromol/kg body mass), demonstrated biphasic kinetics in plasma (t(1/2) = 1.7 and 28 min for the initial and terminal elimination phases, respectively); the volume of distribution of the central compartment corresponded approximately to the total body water. The maximum SMF plasma level was observed at the first sampling time, 2.5 min after HMF administration. On the basis of these kinetic data, it was estimated that between 452 and 551 ppm of the initial HMF dose was converted to SMF and reached the circulation. It is likely that additional SMF reacted with cellular structures at the site of generation and thus is ignored in this balance. Our work supports the hypothesis that HMF-related carcinogenicity may be mediated by its reactive metabolite SMF. PMID:19382817

  14. Isoflavone and Protein Constituents of Lactic Acid-Fermented Soy Milk Combine to Prevent Dyslipidemia in Rats Fed a High Cholesterol Diet

    Maki Kobayashi

    2014-12-01

    Full Text Available A high cholesterol diet induces dyslipidemia. This study investigated whether isoflavone aglycones in lactic acid-fermented soy milk (LFS improve lipid metabolism in rats fed a high cholesterol diet. Male Sprague-Dawley rats aged seven weeks were fed an AIN-93G diet, a 1% cholesterol diet (a high cholesterol diet, a high-cholesterol diet containing 4% isoflavone extract of LFS (LFS extract diet, a high-cholesterol diet containing 19.4% ethanol-washed LFS (ethanol-washed LFS diet, isoflavone-poor diet, or a high cholesterol diet containing 23.2% intact LFS (intact LFS diet for five weeks. The plasma total cholesterol (TC level was increased in the rats fed the LFS extract diet compared with those fed the high cholesterol diet. The TC level was decreased by the intact LFS and ethanol-washed LFS diets. The cholesterol-lowering effect was stronger in the rats fed the intact LFS diet than those fed the ethanol-washed LFS diet. The plasma triglyceride (TG level was unchanged in the rats fed the LFS extract diet, but it decreased in rats fed the intact LFS and ethanol-washed LFS diets. Although, compared with the high cholesterol diet, the LFS extract and ethanol-washed LFS diets did not reduce hepatic cholesterol and TG, both levels were remarkably lowered by the intact LFS diet. These results suggest that the improvement in lipid metabolism of rats fed a high-cholesterol diet containing LFS isoflavone aglycones is not due to an independent effect but due to a cooperative effect with soy protein.

  15. Analysis of gamma irradiated pepper constituents, 1

    A reversed phase high performance liquid chromatographic (HPLC) method was developed for the analysis of many constituents of pepper at the same time. And a extraction method of ultraviolet absorbing constituents from pepper was developed for the HPLC analysis. The Ultraviolet absorbing constituents were extracted by precooled Automatic Air-Hammer from frozen pepper with 20% acetonitrile in water. The process of extraction was achieved under cooling by liquid nitrogen from start to end. The extracted constituents were separated on a reversed phase C8 (LiChrospher 300 RP - 8 10 μm 0.4 I.D. x 0.4 cm and LiChrosorb RP - 8 SelectB 0.4 I. D. x 25 cm) column with a concave gradient from 0.1% trifluoro acetic acid (TFA) in water to 75% acetonitrile and 0.1% TFA in water for 60 minutes. The eluted constituents were detected 210 nm and 280 nm. The present method permits the detection of about 50 peaks by 280 nm. (author)

  16. Peculiarities of coalescence during extraction of scandium by phenol formaldehyde oligomer from sulfate solutions

    Different types of coalescence in extraction system of 0.5 M solution of phenol formaldehyde oligomer in toluene - aqueous scandium sulfuric acid solutions are detected and studied. Condition under the which scandium is extracted in organic phase completely within 30 second are established. Extraction and reextraction of scandium in the cases of different duration of phase contact are investigated. Reproducible regularities of changes of light scattering of extracts and pH values of raffinates in different conditions are revealed. Empirical equation describing coalescence for one of the considered case is presented

  17. Extraction of scandium from chloride solutions using phenolformaldehyde resol oligomer Yarrezin B

    Scandium extraction from acid chloride solutions using phenolformaldehyde resol oligomer Yarrezin B (YRB) was studied by the methods of UV, IR and X-ray photoelectron spectroscopy. In YRB molecules phenol nuclei are bound by methylene, o,o-dimethyleneamine and o,o-dimethyleneether bridges. It was ascertained that under the conditions scandium is extracted by chelate mechanism at metal/reagent ratio 1 : 1, besides, two chlorine atoms and two water molecules are incorporated into the complex. Coordination bond scandium-nitrogen in aminogroup is observed in the complex

  18. Heterogeneous reactions of glyoxal on mineral particles: A new avenue for oligomers and organosulfate formation

    Shen, Xiaoli; Wu, Huihui; Zhao, Yue; Huang, Dao; Huang, Liubin; Chen, Zhongming

    2016-04-01

    Glyoxal (GL) plays a crucial role in the formation of secondary organic aerosols (SOA), because it is highly water soluble and capable of oligomerization. This is the first study to describe irreversible heterogeneous reactions of GL on clean and acidic gas-aged SiO2, α-Al2O3, and CaCO3 particles, as models of real mineral particles, at various relative humidity and without irradiation and gas phase oxidants. A series of products, including oligomers, organosulfates, and organic acids, which contribute to SOA formation, were produced. GL uptake on SO2-aged α-Al2O3 enabled the oxidation of surface S(IV) to S(VI). The presence of adsorbed water on particles favored GL uptake and the formation of oligomers and organosulfate, but it suppressed organic acid formation. In addition, the aging process enhanced the positive effect of adsorbed water on GL uptake. These findings will further our understanding of the GL sink and SOA sources in the atmosphere.

  19. Single-molecule imaging of the oligomer formation of the nonhexameric Escherichia coli UvrD helicase

    Yokota, Hiroaki; Chujo, Yuko Ayabe; Harada, Yoshie

    2013-01-01

    Superfamily I helicases are nonhexameric helicases responsible for the unwinding of nucleic acids. However, whether they unwind DNA in the form of monomers or oligomers remains a controversy. In this study, we addressed this question using direct single-molecule fluorescence visualization of Escherichia coli UvrD, a superfamily I DNA helicase. We performed a photobleaching-step analysis of dye-labeled helicases and determined that the helicase is bound to 18-basepair (bp) double-stranded DNA ...

  20. Effect of Honey-toasting on the Constituents and Contents of Aristolochic Acid Analogues in Aristolochiae Fructus%蜜炙对马兜铃中马兜铃酸类物质含量的影响

    李正红; 杨标; 杨武亮; 陈海芳; 杨明; 袁金斌; 严志宏; 罗小泉

    2013-01-01

    Objective:To evaluate the degree of de-toxification of Aristolochiae Fructus by honey-toasting technology from chemical viewpoint.Methods:The contents of aristolochic acid analogues (AAs)in Aristolochiae Fructus and its honey-toasted product were determined by HPLC,and the degree of de-toxicfication was evaluated comprehensively.Results:After honey-toasted,the contents of AAs decreased to varying degrees,and some new compounds were found.Conclusion:The constituents and contents of Aristolochiae Fructus change after honey-toasted,which indicate honey-toasting can rednce the toxicity of Aristolochiae Fructus.%目的:从化学角度探讨马兜铃蜜炙减毒的程度.方法:采用HPLC法测定马兜铃蜜炙前后几种主要马兜铃酸类成分的含量,并结合其他色谱峰的变化情况综合分析蜜炙减毒的程度.结果:马兜铃经蜜炙后,几种马兜铃酸类物质有不同程度的降低并且有新的物质生成.结论:马兜铃经蜜炙后,其化学成分发生了质和量的变化,证实蜜炙能够减毒.

  1. 一点红化学成分分离及其原儿茶酸含量测定%Isolation of chemical constituents of Emilia sonchifolia and determination of protocatechuic acid

    王立升; 陈淋敏; 张艳华; 庞丽

    2014-01-01

    For the development and utilization of the medicinal worth of Emilia sonchifolia plants, the chemical constituents of Emilia sonchifolia were extracted with water extraction and alcohol pre-cipitation methods. Combined with the use of sub-polar semi-preparative high performance liquid chromatography to isolation the parts of ethyl acetate extract of Emilia sonchifolia aqueous extract and determine the structure of a compound based on their physicochemical properties and spectral data. Five compounds were isolated from the Emilia sonchifolia, which were identified as:4-hydroxyphe-nylacetic acid (1), 4-hydroxybenzoic acid (2), 4-hydroxycinnamic acid (3), protocatechuic acid (4), and syringic acid (5) . All compounds except compound 2 were isolated from this plant for the first time. The determination of protocatechuic acid in Emilia sonchifolia was performed using ex-ternal standard method. The standard curve of protocatechuic acid showed a good linearity in the range of 10~100 μg of concentration with R2=0. 999 5. The method developed in this study was rapid, accurate and easy to be used, therefore it would be good for determination of protocatechuic acid content in Emilia sonchifolia.%为开发利用一点红植物的药用价值,以水提醇沉法提取一点红药材,采用极性分段结合半制备高效液相色谱法分离提取一点红水提物乙酸乙酯萃取部位,并根据理化性质和波谱数据确定其化合物结构,结果从一点红全草药材中分离得到5个单体化合物,经鉴定分别为对羟基苯乙酸(1)、对羟基苯甲酸(2)、对羟基肉桂酸(3)、原儿茶酸(4)、丁香酸(5),除化合物2外的4个化合物均为首次从该植物中分离得到;并采用外标法测定一点红中原儿茶酸的含量,其标准曲线在10~100μg范围内线性关系良好(R2=0.9995),该方法准确度高、重复性好,是一种快速有效的检测一点红中原儿茶酸含量的方法。

  2. Observation of Fano resonances in all-dielectric nanoparticle oligomers.

    Chong, Katie E; Hopkins, Ben; Staude, Isabelle; Miroshnichenko, Andrey E; Dominguez, Jason; Decker, Manuel; Neshev, Dragomir N; Brener, Igal; Kivshar, Yuri S

    2014-05-28

    It is well-known that oligomers made of metallic nanoparticles are able to support sharp Fano resonances originating from the interference of two plasmonic resonant modes with different spectral width. While such plasmonic oligomers suffer from high dissipative losses, a new route for achieving Fano resonances in nanoparticle oligomers has opened up after the recent experimental observations of electric and magnetic resonances in low-loss dielectric nanoparticles. Here, light scattering by all-dielectric oligomers composed of silicon nanoparticles is studied experimentally for the first time. Pronounced Fano resonances are observed for a variety of lithographically-fabricated heptamer nanostructures consisting of a central particle of varying size, encircled by six nanoparticles of constant size. Based on a full collective mode analysis, the origin of the observed Fano resonances is revealed as a result of interference of the optically-induced magnetic dipole mode of the central particle with the collective mode of the nanoparticle structure. This allows for effective tuning of the Fano resonance to a desired spectral position by a controlled size variation of the central particle. Such optically-induced magnetic Fano resonances in all-dielectric oligomers offer new opportunities for sensing and nonlinear applications. PMID:24616191

  3. TAU OLIGOMERS AS DIRECT TARGETS FOR ALZHEIMER´S DIAGNOSIS AND NOVEL DRUGS

    Leonardo eGuzman-Martinez

    2013-10-01

    Full Text Available A cumulative number of approaches have been carried out to elucidate the pathogenesis of Alzheimer´s disease (AD. Tangle formation has been identified as a major event involved in the neurodegenerative process, due to the conversion of either soluble peptides or oligomers into insoluble filaments. Most of recent studies share in common the observation that formation of tau oligomers and the subsequent pathological filaments arrays is a critical step in AD etiopathogenesis. Oligomeric tau species appear to be neurotoxic for neuronal cells, and therefore appear as an appropriate target for the design of molecules that may control morphological and functional alterations leading to cognitive impairment. Thus, current therapeutic strategies are aimed at three major types of molecules: 1 Inhibitors of protein kinases and phosphatases that may control neuronal degeneration, 2 Methylene blue, and 3 Natural phytocomplexes and polyphenolics compounds able to either inhibit the formation of tau filaments or disaggregate them. Only a few polyphenolic molecules have emerged to prevent tau aggregation. Fulvic acid, a humic substance, has a potential activity to protect cognitive impairment. In fact, formation of paired helical filaments (PHFs in vitro, is inhibited by fulvic acid affecting the length of fibrils and their morphology.

  4. Oligomer Molecules for Efficient Organic Photovoltaics.

    Lin, Yuze; Zhan, Xiaowei

    2016-02-16

    Solar cells, a renewable, clean energy technology that efficiently converts sunlight into electricity, are a promising long-term solution for energy and environmental problems caused by a mass of production and the use of fossil fuels. Solution-processed organic solar cells (OSCs) have attracted much attention in the past few years because of several advantages, including easy fabrication, low cost, lightweight, and flexibility. Now, OSCs exhibit power conversion efficiencies (PCEs) of over 10%. In the early stage of OSCs, vapor-deposited organic dye materials were first used in bilayer heterojunction devices in the 1980s, and then, solution-processed polymers were introduced in bulk heterojunction (BHJ) devices. Relative to polymers, vapor-deposited small molecules offer potential advantages, such as a defined molecular structure, definite molecular weight, easy purification, mass-scale production, and good batch-to-batch reproducibility. However, the limited solubility and high crystallinity of vapor-deposited small molecules are unfavorable for use in solution-processed BHJ OSCs. Conversely, polymers have good solution-processing and film-forming properties and are easily processed into flexible devices, whereas their polydispersity of molecular weights and difficulty in purification results in batch to batch variation, which may hamper performance reproducibility and commercialization. Oligomer molecules (OMs) are monodisperse big molecules with intermediate molecular weights (generally in the thousands), and their sizes are between those of small molecules (generally with molecular weights 10000). OMs not only overcome shortcomings of both vapor-deposited small molecules and solution-processed polymers, but also combine their advantages, such as defined molecular structure, definite molecular weight, easy purification, mass-scale production, good batch-to-batch reproducibility, good solution processability, and film-forming properties. Therefore, OMs are a

  5. Liquid chromatographic fractionations of mixtures of polystyrene oligomers

    Oligomer mixtures of 800, 2200, and 4000 molecular weight polystyrene have been fractionated using silica and bonded phase columns under similar conditions of solvent gradient and flow rate. Using a hexane tetrahydrofuran gradient, the silica and nitro phases were best in that they separated 41 and 43 oligomers, respectively. At the other extreme, a phenyl bonded phase column gave virtually no resolution using a water/THF gradient, and a cyano bonded phase column, using the earlier hexane/tetrahydrofuran system, resolved only 10 oligomers. Amino and octadecyl bonded phase columns gave results intermediate between these two extremes. The strength of the solvent used to dissolve the sample was found to be of critical importance. Use of too good a sample solvent seriously degraded the attainable resolution. When number-average and weight-average molecular weights for an 800 molecular weight polystyrene sample were calculated from the oligomer distribution, the silica column gave values which were most consistent with those reported from other methods. 5 figures, 4 tables

  6. Plasma amyloid beta peptides and oligomers antibodies in Alzheimer's disease

    Zhou, L.; Chu, LW; Kwan, JSC; Ho, JWM; Lam, KSL; Ho, PWL; Chan, KH

    2011-01-01

    INTRODUCTION: Various forms of amyloid beta (Aβ) including Aβ peptides, oligomers, protofibrils and fibrils are thought to be pathogenic in Alzheimer’s disease (AD). The exact pathophysiological role of endogenous Aβ autoantibodies (Ab) in healthy subjects and AD patients are uncertain. Potential protective role ...

  7. Mass Spectrometric Characterization of Oligomers in Pseudomonas aeruginosa Azurin Solutions

    Sokolová, L.; Williamson, H.; Sýkora, Jan; Hof, Martin; Gray, H. B.; Brutschy, B.; Vlček Jr., Antonín

    2011-01-01

    Roč. 115, č. 16 (2011), s. 4790-4800. ISSN 1520-6106 R&D Projects: GA MŠk(CZ) ME10124; GA MŠk(CZ) LC06063 Institutional research plan: CEZ:AV0Z40400503 Keywords : mass spectrometry * oligomers * pseudomonas aeruginosa azurin solutions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.696, year: 2011

  8. The oxidation of aniline to aniline oligomers and polyaniline

    Stejskal, Jaroslav; Trchová, Miroslava

    Istanbul: International Union of Pure and Applied Chemistry, 2013. s. 878. [World Chemistry Congress /44./. 11.08.2013-16.08.2013, Istanbul] R&D Projects: GA MŠk LG13037 Institutional support: RVO:61389013 Keywords : anilin e oligomers * polyaniline * microflowers Subject RIV: CD - Macromolecular Chemistry

  9. Self-assembly of 33-mer gliadin peptide oligomers.

    Herrera, M G; Benedini, L A; Lonez, C; Schilardi, P L; Hellweg, T; Ruysschaert, J-M; Dodero, V I

    2015-11-28

    The 33-mer gliadin peptide, LQLQPF(PQPQLPY)3PQPQPF, is a highly immunogenic peptide involved in celiac disease and probably in other immunopathologies associated with gliadin. Herein, dynamic light scattering measurements showed that 33-mer, in the micromolar concentration range, forms polydisperse nano- and micrometer range particles in aqueous media. This behaviour is reminiscent of classical association of colloids and we hypothesized that the 33-mer peptide self-assembles into micelles that could be the precursors of 33-mer oligomers in water. Deposition of 33-mer peptide aqueous solution on bare mica generated nano- and microstructures with different morphologies as revealed by atomic force microscopy. At 6 μM, the 33-mer is organised in isolated and clusters of spherical nanostructures. In the 60 to 250 μM concentration range, the spherical oligomers associated mainly in linear and annular arrangements and structures adopting a "sheet" type morphology appeared. At higher concentrations (610 μM), mainly filaments and plaques immersed in a background of nanospherical structures were detected. The occurrence of different morphologies of oligomers and finally the filaments suggests that the unique specific geometry of the 33-mer oligomers has a crucial role in the subsequent condensation and organization of their fractal structures into the final filaments. The self-assembly process on mica is described qualitatively and quantitatively by a fractal diffusion limited aggregation (DLA) behaviour with the fractal dimension in the range of 1.62 ± 0.02 to 1.73 ± 0.03. Secondary structure evaluation of the oligomers by Attenuated Total Reflection FTIR spectroscopy (ATR-FTIR) revealed the existence of a conformational equilibrium of self-assembled structures, from an extended conformation to a more folded parallel beta elongated structures. Altogether, these findings provide structural and morphological information about supramolecular organization of the 33-mer

  10. Design, synthesis, and characterization of biomimetic oligomers

    Laursen, Jonas Striegler

    Peptides and proteins made from the 20 canonical amino acids are responsible for many processes necessary for organisms to function. Beside their composition, proteins obtain their activity and unique selectivity through an ability to display functionalities accurately in the three-dimensional sp...

  11. Study of Synthesis of Copoly (lactic acid/glycolic acid) by Direct Melt Polycondensation

    LAN Ping; GAO Qin-wei; SHAO Hui-li; HU Xue-chao

    2005-01-01

    A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/ptoluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.

  12. Alteration of the selectivity of hybridization of immobilized oligonucleotide probes by co-immobilization with charged oligomers of ethylene glycol

    A significant challenge exists in the creation of an environment for immobilized probe oligonucleotides that offer good structural regularity and reproducibility, where nearest neighbour interactions provide for control of selectivity, yet where the degree of hybridization does not alter nearest neighbour interactions. This new work explores whether a 'matrix isolation' method will produce the desired environment for the probe molecules. The DNA oligonucleotide probes are polyelectrolytes with charged backbones and significant flexibility. It is possible to isolate the probe molecules by surrounding each, on average, with a sheath of immobilized oligomer that is not based on complementary nucleic acid, yet that is a polyelectrolyte in order to control the surface density and charge within the mixed film. Preliminary work investigates a mixture of dT20 as the probe oligonucleotide, and a 20-mer oligomer primarily containing ethylene glycol phosphate, as a matrix isolation material in a 1:20 mole ratio, respectively. Melt temperature (Tm) measurements indicate that the thermodynamic stability of the probe molecules can be adjusted using the oligomer matrix to achieve lower Tm values by up to 5 deg. C, with full retention of selectivity for discrimination of single base pair mismatches even under conditions where the probes at a surface are saturated with complementary target

  13. An electric nose based on arylenevinylene polymers and oligomers

    de Wit, Michael

    An electronic nose is an instrument, which comprises an array of electronic chemical sensors with partial specificity and an appropriate pattern-recognition system, capable of recognising simple or complex odours. Our efforts are centred around the sensors part of the nose. In fact, we applied a number of polymeric and oligomeric members of the arylenevinylene group of molecules as the active layer for conductimetric sensors (chemiresistors). The electric resistance of the active layer changes when it is exposed to vapors. The response of the sensor on a vapour is defined as the fractional, percentual change of the resistance compared to that in clean air. We made the sensors by depositing the organic layers on a substrate containing pre-printed gold contacts. At first we tested poly(2,5-thienylene vinylene) (PTV). A synthetic method was employed in which a soluble methoxy-precursor polymer of PTV was isolated, which was then spin-coated onto the substrate, and after being converted thermally to PTV, subsequently doped by iodine. The values of the responses of the PTV sensors are comparable to those sensors based on other conducting polymers, but the (partial) selectivity for the vapors is different. The responses of the PTV sensor are linearly related to the concentration. Incomplete conversion of the precursor polymer to the final PTV leads to copolymers of methoxy-PTV and PTV itself varying inter alia in the degree of conjugation. Chemiresistors based on these new materials show an affinity to vapors differing from that of PTV. We discovered that the arylenevinylenes need not to be of polymeric nature for this application. In fact, the arylenevinylene oligomers perform better. The oligomers are easier to modify and to process than polymers. We tested 2,5-dimethoxy-1,4-bis(3,4,5-trimethoxystyrylbenzene) (OMT) in its pure form and in blends with polycarbonate. The responses of these oligomeric sensors are on the average five times higher than those of the

  14. Chemical constituents of Salacia elliptica (Celastraceae)

    Duarte, Lucienir Pains; Figueiredo, Rute Cunha; Sousa, Grasiely Faria de; Soares, Debora Barbosa da Silva; Rodrigues, Salomao Bento Vasconcelos; Silva, Fernando Cesar; Silva, Gracia Divina de Fatima, E-mail: lucienir@ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Vieira Filho, Sidney Augusto [Universidade Federal de Ouro Preto, MG (Brazil). Escola de Farmacia. Dept. de Farmacia

    2010-07-01

    The chemical investigation of Salacia elliptica allowed to the isolation of 20 constituents: two polyols, one xanthone, a mixture of long chain hydrocarbons, one carboxylic acid, one polymer, two steroidal compounds, one aromatic ester and eleven pentacyclic triterpenes. These triterpenes include 3{beta}-stearyloxy-oleanane, 3{beta}-stearyloxy-ursane, one seco-friedelane, and eight compounds of the friedelane series. The chemical structure and the relative configuration of a new triterpene 1,3-dioxo-16alpha-hydroxyfriedelane (15) were established through {sup 1}H and {sup 13}C NMR including 2D experiments (HMBC, HMQC, COSY and NOESY) and herein reported for the first time (author)

  15. Charge transfer in conjugated oligomers encapsulated into carbon nanotubes

    Almadori, Y.; Alvarez, L.; Michel, T.; Le Parc, R.; Bantignies, J.L.; Hermet, P.; Sauvajol, J.L. [Laboratoire Charles Coulomb UMR 5521, Universite Montpellier 2, 34095 Montpellier (France); Laboratoire Charles Coulomb UMR 5521, CNRS, 34095 Montpellier (France); Arenal, R. [Laboratoire d' Etude des Microstructures, CNRS-ONERA, 92322 Chatillon (France); Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, U. Zaragoza, 50018 Zaragoza (Spain); Babaa, R. [Laboratoire de Chimie des Surfaces et Interfaces, CEA, IRAMIS, SPCSI, 91191 Gif-sur-Yvette Cedex (France); Chemical Engineering Department, University of Technology PETRONAS, UTP, Ipoh-Perak (Malaysia); Jouselme, B.; Palacin, S. [Laboratoire de Chimie des Surfaces et Interfaces, CEA, IRAMIS, SPCSI, 91191 Gif-sur-Yvette Cedex (France)

    2011-11-15

    This study deals with a hybrid system consisting in quaterthiophene derivative encapsulated inside single-walled and multi-walled carbon nanotubes. Investigations of the encapsulation step are performed by transmission electron microscopy. Raman spectroscopy data point out different behaviors depending on the laser excitation energy with respect to the optical absorption of quaterthiophene. At low excitation energy (far from the oligomer resonance window) there is no significant modification of the Raman spectra before and after encapsulation. By contrast, at high excitation energy (close to the oligomer resonance window), Raman spectra exhibit a G-band shift together with an important RBM intensity loss, suggesting a significant charge transfer between the inserted molecule and the host nanotubes. Those results suggest a photo induced process leading to a significant charge transfer. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Ultrafast Killing and Self-Gelling Antimicrobial Imidazolium Oligomers.

    Riduan, Siti Nurhanna; Yuan, Yuan; Zhou, Feng; Leong, Jiayu; Su, Haibin; Zhang, Yugen

    2016-04-01

    Infectious diseases and the increasing threat of worldwide pandemics have underscored the importance of antibiotics and hygiene. Intensive efforts have been devoted to developing new antibiotics to meet the rapidly growing demand. In particular, advancing the knowledge of the structure-property-activity relationship is critical to expedite the design and development of novel antimicrobial with the needed potential and efficacy. Herein, a series of new antimicrobial imidazolium oligomers are developed with the rational manipulation of terminal group's hydrophobicity. These materials exhibit superior activity, excellent selectivity, ultrafast killing (>99.7% killing within 30 s), and desirable self-gelling properties. Molecular dynamic simulations reveal the delicate effect of structural changes on the translocation motion across the microbial cell membrane. The energy barrier of the translocation process analyzed by free energy calculations provides clear kinetic information to suggest that the spontaneous penetration requires a very short timescale of seconds to minutes for the new imidazolium oligomers. PMID:26891016

  17. Some biological actions of PEG-conjugated RNase A oligomers

    Poučková, P.; Škvor, J.; Gotte, G.; Vottariello, F.; Slavík, Tomáš; Matoušek, Josef; Laurents, D. V.; Libonati, M.; Souček, J.

    2006-01-01

    Roč. 53, č. 1 (2006), s. 79-85. ISSN 0028-2685 R&D Projects: GA ČR GA523/04/0755; GA MZd NR8233 Grant ostatní: Spanish Ministerio de Ciencia y Technologia BQU2003-05227 Institutional research plan: CEZ:AV0Z50450515 Keywords : RNase A oligomers * polyethylene glycol conjugates * anti-tumour activity Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.247, year: 2006

  18. Circular dichroism from Fano resonances in planar chiral oligomers

    Hopkins, Ben; Poddubny, Alexander N.; Miroshnichenko, Andrey E.; Kivshar, Yuri S.

    2015-05-01

    Here we present a general approach for describing the physics of Fano resonances in nanoparticle oligomers. It is shown that the interference of nonorthogonal collective eigenmodes is a sufficient condition to produce Fano resonances. We then show that such nonorthogonality between eigenmodes also permits the existence of a new form circular dichroism in the absorption and scattering cross-sections, even when circular dichroism is forbidden in the extinction cross-section.

  19. Microspherical aniline oligomers and their nitrogen-containing carbon analogues

    Rozlívková, Zuzana; Trchová, Miroslava; Konyushenko, Elena; Stejskal, Jaroslav

    Granada : European Polymer Federation, 2011. s. 1166. ISBN 978-84-694-3124-5. [European Polymer Congress 2011, Congress of the Specialized Group of Polymers /12./. 26.06.2011-01.07.2011, Granada] R&D Projects: GA AV ČR IAA100500902 Institutional research plan: CEZ:AV0Z40500505 Keywords : anilin e oligomers * self-assembly * carbonization Subject RIV: CD - Macromolecular Chemistry

  20. The Viscoelastic Behavior of Polymer/Oligomer Blends

    Zheng, Wei; McKenna, Gregory; Simon, Sindee

    2009-03-01

    The dynamics in athermal blends of poly(α-methyl styrene) (PaMS) and its short chain oligomer are investigated using rheometry and differential scanning calorimetry (DSC). Master curves for the dynamic shear responses, G' and G", are successfully constructed for both the pure materials and the blends, indicating the validity of the time-temperature superposition principle. The temperature dependence of the shift factor follows the WLF (Williams-Landel-Ferry) behavior over the temperature range studied, and for the blends, the dependence is dominated by the high mobility oligomer. The discrete relaxation spectra of the materials are calculated and are found to be broader for the blends than for the pure materials. A similar domination of the dynamics by the oligomer is observed in DSC enthalpy recovery studies and in the broadened glass transition from DSC. The ability to predict the dynamic responses of the blends from the responses of the neat materials is examined, and whether this prediction needs to incorporate the self-concentration idea as described in Colmenero's model will be discussed.

  1. Aβ42 oligomers selectively disrupt neuronal calcium release.

    Lazzari, Cristian; Kipanyula, Maulilio J; Agostini, Mario; Pozzan, Tullio; Fasolato, Cristina

    2015-02-01

    Accumulation of amyloid-β (Aβ) peptides correlates with aging and progression of Alzheimer's disease (AD). Aβ peptides, which cause early synaptic dysfunctions, spine loss, and memory deficits, also disturb intracellular Ca(2+) homeostasis. By cytosolic and endoplasmic reticulum Ca(2+) measurements, we here define the short-term effects of synthetic Aβ42 on neuronal Ca(2+) dynamics. When applied acutely at submicromolar concentration, as either oligomers or monomers, Aβ42 did not cause Ca(2+) release or Ca(2+) influx. Similarly, 1-hour treatment with Aβ42 modified neither the resting cytosolic Ca(2+) level nor the long-lasting Ca(2+) influx caused by KCl-induced depolarization. In contrast, Aβ42 oligomers, but not monomers, significantly altered Ca(2+) release from stores with opposite effects on inositol 1,4,5-trisphosphate (IP3)- and caffeine-induced Ca(2+) mobilization without alteration of the total store Ca(2+) content. Ca(2+) dysregulation by Aβ42 oligomers involves metabotropic glutamate receptor 5 and requires network activity and the intact exo-endocytotic machinery, being prevented by tetrodotoxin and tetanus toxin. These findings support the idea that Ca(2+) store dysfunction is directly involved in Aβ42 neurotoxicity and represents a potential therapeutic target in AD-like dementia. PMID:25453559

  2. SELECTIVE TRANSPORT OF GOLD(Ⅱ) THROUGH THE LIQUID MEMBRANE CONTAINING POLYTHIOETHER OLIGOMER AS CARRIER

    XUYuwu; WANGYing; 等

    1993-01-01

    This paper deals with the transport properties of oligomer of polythioether PSA used as moble carrier in bulk liquid membrane for gold(Ⅲ).It was found that Au(Ⅲ) can be transported by PSA from source phase to receiving phase completely under appropriate conditions and only Au(Ⅲ) can be transferred through the liquid membrane to receiving phase from a mixture of Na(I)-Cu(Ⅱ)-Au(Ⅲ)-Fe(Ⅲ)-Pt(Ⅳ) in the following system:HAuCl4-HCl(aq.)/PSA-ClCH2-CH2Cl/(NH2)2CS-HCl(aq.).The transport rate of Au(Ⅲ) depended on the concentration of carrier,the thickness of liquid membrane,the concentration of Au(Ⅲ) in source phase and the acidity of the media.

  3. Characterization of radiation modified κ-carrageenan oligomers for bio-based materials development

    κ-carrageenan oligomers are known to have several biological activities such as anti-HIV, anti-herpes, antitumor and antioxidant properties. Recent progress in the development of radiation modified κ-carrageenan has resulted in new applications such as plant growth promoter, radiation dose indicator and hydrogels for wound dressing. This presentation would touch on the changes in chemical structure, gelation and conformational transition behavior and molecular size of κ-carrageenan at doses from 0 to 200 kGy and would be correlated to these functions for the development of bio-based materials. Chemical and spectral analyses were carried out using UV-Vis spectroscopy, FT-IR spectroscopy, NMR spectroscopy, reducing sugar analysis, free sulfate and carboxylic acid analysis. The chemical and spectral analyses of the radiolytic products indicated increasing reducing sugars, carbonyl, carboxylic acids, and sulfates with increasing doses which reached a maximum level at a certain dose depending on the irradiation condition. Values were very much lower in solid irradiation (in vacuum and in air) as compared to aqueous irradiation. NMR data also revealed an intact structure of the oligomer irradiated at 100 kGy in the specific fraction that contains an Mw = (3-10) kDa. κ-carrageenan oligomers exhibited antioxidant properties as determined by hydroxyl radical scavenging activity, reducing power and DPPH radical scavenging capacity assay. The degree of oxidative inhibition increased with increasing dose which can be attributed to higher reducing sugar. Dynamic light scattering (DLS) experiments showed that a dose of up to 50 kGy, sol-gelation transition was still observed. Beyond 50 kGy, no gelation took place, instead appearance of fast relax-carrageenan mode in characteristic decay time function was observed at doses of (75-150) kGy. Optimum peak intensity was found at 100 kGy (mol wt. 5-10 kDa) which coincides with the optimum plant growth promoter effect in κ

  4. Microwave-assisted click polymerization for the synthesis of Abeta(16-22) cyclic oligomers and their self-assembly into polymorphous aggregates.

    Elgersma, Ronald C; van Dijk, Maarten; Dechesne, Annemarie C; van Nostrum, Cornelus F; Hennink, Wim E; Rijkers, Dirk T S; Liskamp, Rob M J

    2009-11-01

    We report on the design, synthesis, and structural analysis of cyclic oligomers with an amyloidogenic peptide sequence as the repeating unit to obtain novel self-assembling bionanomaterials. The peptide was derived from the Alzheimer Abeta(16-22) sequence since its strong tendency to form antiparallel beta-sheets ensured the formation of intermolecular hydrogen bridges on which the supramolecular assembly of the individual cyclic oligomers was based. The synthesis of the cyclic oligomers was performed via a microwave-assisted Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction of azido-Lys-Leu-Val-Phe-Phe-Ala-Glu-propargyl amide as the monomer. The formation of cyclic oligomers, up to pentamers (35 amino acid residues), was verified by MALDI-TOF analysis and the individual cyclic monomer and dimer could be isolated by HPLC. Gelation behavior and the self-assembly of the linear monomer and the cyclic monomer and dimer were studied by TEM, FTIR and CD. Significant differences were observed in the morphology of the supramolecular aggregates of these three peptides that could be explained by alterations of the hydrogen bond network. PMID:19830304

  5. Pyridine-containing m-phenylene ethynylene oligomers having tunable basicities.

    Heemstra, Jennifer M; Moore, Jeffrey S

    2004-03-01

    Incorporation of a pyridine monomer into the backbone of a m-phenylene ethynylene oligomer allows functionalization of the interior binding cavity of the folded oligomer. The basicity of the inwardly directed pyridine moiety was modulated by changing the substituents on the pyridine ring and through oligomer folding, granting access to a pK(a) range of 5-14 in acetonitrile. [reaction: see text] PMID:14986943

  6. Antiinflammatory constituents of teramnus labialis

    Sridhar C

    2006-01-01

    Full Text Available Bioassay-guided fractionation, based on antiinflammatory activity of the methanolic extractives of Teramnus labialis led to the isolation and characterization of vitexin, bergenin, daidzin and 3-O-methyl-D- chiro -inositol as active constituents. Vitexin exhibited a dose-dependent inhibitory activity on 5-lipoxygenase enzyme. The isolated constituents were also screened for their antioxidant activity by nitroblue tetrazolium (NBT riboflavin photo reduction method. Vitexin exhibited moderate antioxidant activity. This is the first reported occurrence of vitexin, bergenin, daidzin and 3-O-methyl-D- chiro -inositol in T. labialis.

  7. Adsorption behavior of conjugated {C}3-oligomers on Si(100) and HOPG surfaces

    Mahieu, G; Stiévenard, Didier; Krzeminski, Christophe; Delerue, Christophe; Roncali, Jean; Martineau, C; 10.1021/la026907n

    2012-01-01

    A pi-conjugated {C}3h-oligomer involving three dithienylethylene branches bridged at the meta positions of a central benzenic core has been synthesized and deposited either on the Si(100) surface or on the HOPG surface. On the silicon surface, scanning tunneling microscopy allows the observation of isolated molecules. Conversely, by substituting the thiophene rings of the oligomers with alkyl chains, a spontaneous ordered film is observed on the HOPG surface. As the interaction of the oligomers is different with both surfaces, the utility of the Si(100) surface to characterize individual oligomers prior to their use into a 2D layer is discussed.

  8. Gene-Specific Effects of Antisense Phosphorodiamidate Morpholino Oligomer-Peptide Conjugates on Escherichia coli and Salmonella enterica Serovar Typhimurium in Pure Culture and in Tissue Culture

    Lucas D Tilley; Hine, Orion S.; Kellogg, Jill A.; Hassinger, Jed N.; Weller, Dwight D.; Iversen, Patrick L.; Geller, Bruce L.

    2006-01-01

    The objective was to improve efficacy of antisense phosphorodiamidate morpholino oligomers (PMOs) by improving their uptake into bacterial cells. Four different bacterium-permeating peptides, RFFRFFRFFXB, RTRTRFLRRTXB, RXXRXXRXXB, and KFFKFFKFFKXB (X is 6-aminohexanoic acid and B is β-alanine), were separately coupled to two different PMOs that are complementary to regions near the start codons of a luciferase reporter gene (luc) and a gene required for viability (acpP). Luc peptide-PMOs targ...

  9. Dietary Supplements and Sports Performance: Metabolites, Constituents, and Extracts

    Williams Melvin

    2006-01-01

    Abstract This is the fifth in a series of six articles to discuss the major classes of dietary supplements (vitamins; minerals; amino acids; herbs or botanicals; and metabolites/constituents/extracts). The major focus is on efficacy of such dietary supplements to enhance exercise or sports performance.

  10. Dietary Supplements and Sports Performance: Metabolites, Constituents, and Extracts

    Williams Melvin

    2006-12-01

    Full Text Available Abstract This is the fifth in a series of six articles to discuss the major classes of dietary supplements (vitamins; minerals; amino acids; herbs or botanicals; and metabolites/constituents/extracts. The major focus is on efficacy of such dietary supplements to enhance exercise or sports performance.

  11. Antifungal constituents of Melicope borbonica

    Simonsen, Henrik Toft; Adsersen, Anne; Bremner, Paul;

    2004-01-01

    -methoxycoumarin, cedrelopsin and psoralen], two sesquiterpenes (alpha-curcumene and 3,6-epidioxy-1,10-bisaboladiene), eugenol, methyleugenol and a lignan (sesamin) were isolated. None of the isolated constituents exhibited antiin fl ammatory activity in vitro. No alkaloids were detected....

  12. Inactivation of lipoprotein lipase occurs on the surface of THP-1 macrophages where oligomers of angiopoietin-like protein 4 are formed

    Makoveichuk, Elena; Sukonina, Valentina; Kroupa, Olessia [Department of Medical Biosciences, Physiological Chemistry Umea University, SE-901 87 Umea (Sweden); Thulin, Petra; Ehrenborg, Ewa [Atherosclerosis Research Unit, Department of Medicine, Karolinska Institutet, SE-171 76 Stockholm (Sweden); Olivecrona, Thomas [Department of Medical Biosciences, Physiological Chemistry Umea University, SE-901 87 Umea (Sweden); Olivecrona, Gunilla, E-mail: Gunilla.Olivecrona@medbio.umu.se [Department of Medical Biosciences, Physiological Chemistry Umea University, SE-901 87 Umea (Sweden)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Lipoprotein lipase (LPL) activity is controlled by ANGPTL4 in THP-1 macrophages. Black-Right-Pointing-Pointer Both LPL and ANGPTL4 bind to THP-1 macrophages in a heparin-releasable fashion. Black-Right-Pointing-Pointer Only monomers of ANGPTL4 are present within THP-1 macrophages. Black-Right-Pointing-Pointer Covalent oligomers of ANGPTL4 appear on cell surface and in medium. Black-Right-Pointing-Pointer Inactivation of LPL coincide with ANGPTL4 oligomer formation on cell surfaces. -- Abstract: Lipoprotein lipase (LPL) hydrolyzes triglycerides in plasma lipoproteins causing release of fatty acids for metabolic purposes in muscles and adipose tissue. LPL in macrophages in the artery wall may, however, promote foam cell formation and atherosclerosis. Angiopoietin-like protein (ANGPTL) 4 inactivates LPL and ANGPTL4 expression is controlled by peroxisome proliferator-activated receptors (PPAR). The mechanisms for inactivation of LPL by ANGPTL4 was studied in THP-1 macrophages where active LPL is associated with cell surfaces in a heparin-releasable form, while LPL in the culture medium is mostly inactive. The PPAR{delta} agonist GW501516 had no effect on LPL mRNA, but increased ANGPTL4 mRNA and caused a marked reduction of the heparin-releasable LPL activity concomitantly with accumulation of inactive, monomeric LPL in the medium. Intracellular ANGPTL4 was monomeric, while dimers and tetramers of ANGPTL4 were present in the heparin-releasable fraction and medium. GW501516 caused an increase in the amount of ANGPTL4 oligomers on the cell surface that paralleled the decrease in LPL activity. Actinomycin D blocked the effects of GW501516 on ANGPTL4 oligomer formation and prevented the inactivation of LPL. Antibodies against ANGPTL4 interfered with the inactivation of LPL. We conclude that inactivation of LPL in THP-1 macrophages primarily occurs on the cell surface where oligomers of ANGPTL4 are formed.

  13. Inactivation of lipoprotein lipase occurs on the surface of THP-1 macrophages where oligomers of angiopoietin-like protein 4 are formed

    Highlights: ► Lipoprotein lipase (LPL) activity is controlled by ANGPTL4 in THP-1 macrophages. ► Both LPL and ANGPTL4 bind to THP-1 macrophages in a heparin-releasable fashion. ► Only monomers of ANGPTL4 are present within THP-1 macrophages. ► Covalent oligomers of ANGPTL4 appear on cell surface and in medium. ► Inactivation of LPL coincide with ANGPTL4 oligomer formation on cell surfaces. -- Abstract: Lipoprotein lipase (LPL) hydrolyzes triglycerides in plasma lipoproteins causing release of fatty acids for metabolic purposes in muscles and adipose tissue. LPL in macrophages in the artery wall may, however, promote foam cell formation and atherosclerosis. Angiopoietin-like protein (ANGPTL) 4 inactivates LPL and ANGPTL4 expression is controlled by peroxisome proliferator-activated receptors (PPAR). The mechanisms for inactivation of LPL by ANGPTL4 was studied in THP-1 macrophages where active LPL is associated with cell surfaces in a heparin-releasable form, while LPL in the culture medium is mostly inactive. The PPARδ agonist GW501516 had no effect on LPL mRNA, but increased ANGPTL4 mRNA and caused a marked reduction of the heparin-releasable LPL activity concomitantly with accumulation of inactive, monomeric LPL in the medium. Intracellular ANGPTL4 was monomeric, while dimers and tetramers of ANGPTL4 were present in the heparin-releasable fraction and medium. GW501516 caused an increase in the amount of ANGPTL4 oligomers on the cell surface that paralleled the decrease in LPL activity. Actinomycin D blocked the effects of GW501516 on ANGPTL4 oligomer formation and prevented the inactivation of LPL. Antibodies against ANGPTL4 interfered with the inactivation of LPL. We conclude that inactivation of LPL in THP-1 macrophages primarily occurs on the cell surface where oligomers of ANGPTL4 are formed.

  14. Characterization of glycidyl methacrylate - crosslinked hyaluronan hydrogel scaffolds incorporating elastogenic hyaluronan oligomers.

    Ibrahim, S; Kothapalli, C R; Kang, Q K; Ramamurthi, A

    2011-02-01

    Prior studies on two-dimensional cell cultures suggest that hyaluronic acid (HA) stimulates cell-mediated regeneration of extracellular matrix structures, specifically those containing elastin, though such biologic effects are dependent on HA fragment size. Towards being able to regenerate three-dimensional (3-D) elastic tissue constructs, the present paper studies photo-crosslinked hydrogels containing glycidyl methacrylate (GM)-derivatized bio-inert high molecular weight (HMW) HA (1 × 10(6)Da) and a bioactive HA oligomer mixture (HA-o: MW ∼0.75 kDa). The mechanical (rheology, degradation) and physical (apparent crosslinking density, swelling ratio) properties of the gels varied as a function of incorporated HA oligomer content; however, overall, the mechanics of these hydrogels were too weak for vascular applications as stand-alone materials. Upon in vivo subcutaneous implantation, only a few inflammatory cells were evident around GM-HA gels, however their number increased as HA-o content within the gels increased, and the collagen I distribution was uniform. Smooth muscle cells (SMC) were encapsulated into GM hydrogels, and calcein acetoxymethyl detection revealed that the cells were able to endure twofold the level of UV exposure used to crosslink the gels. After 21 days of culture, SMC elastin production, measured by immunofluorescence quantification, showed HA-o to increase cellular deposition of elastic matrix twofold relative to HA-o-free GM-HA gels. These results demonstrate that cell response to HA/HA-o is not altered by their methacrylation and photo-crosslinking into a hydrogel, and that HA-o incorporation into cell-encapsulating hydrogel scaffolds can be useful for enhancing their production of elastic matrix structures in a 3-D space, important for regenerating elastic tissues. PMID:20709199

  15. Conformation of chromatin oligomers. A new argument for a change with the hexanucleosome.

    Marion, C; Bezot, P; Hesse-Bezot, C; Roux, B; Bernengo, J C

    1981-11-01

    Quasielastic laser light scattering measurements have been made on chromatin oligomers to obtain information on the transition in their electrooptical properties, previously observed for the hexameric structures [Marion, C. and Roux, B. (1978) Nucleic Acids Res. 5, 4431-4449]. Translational diffusion coefficients were determined for mononucleosomes to octanucleosomes containing histone H1 over a range of ionic strength. At high ionic strength, oligomers show a linear dependence of the logarithm of diffusion coefficient upon the logarithm of number of nucleosomes. At low ionic strength a change occurs between hexamer and heptamer. Our results agree well with the recent sedimentation data of Osipova et al. [Eur. J. Biochem. (1980) 113, 183-188] and of Butler and Thomas [J. Mol. Biol. (1980) 140, 505-529] showing a change in stability with hexamer. Various models for the arrangements of nucleosomes in the superstructure of chromatin are discussed. All calculations clearly indicate a conformational change with the hexanucleosome and the results suggest that, at low ionic strength, the chromatin adopts a loosely helical structure of 28-nm diameter and 22-nm pitch. These results are also consistent with a discontinuity every sixth nucleosome, corresponding to a turn of the helix. This discontinuity may explain the recent electric dichroism data of Lee et al. [Biochemistry (1981) 20, 1438-1445]. The hexanucleosome structure which we have previously suggested, with the faces of nucleosomes arranged radially to the helical axis has been recently confirmed by Mc Ghee et al. [Cell (1980) 22, 87-96]. With an increase of ionic strength, the helix becomes more regular and compact with a slightly reduced outer diameter and a decreased pitch, the dimensions resembling those proposed for solenoid models. PMID:7308214

  16. Effect of synthetic aβ peptide oligomers and fluorinated solvents on Kv1.3 channel properties and membrane conductance.

    Maria I Lioudyno

    Full Text Available The impact of synthetic amyloid β (1-42 (Aβ(1-42 oligomers on biophysical properties of voltage-gated potassium channels Kv 1.3 and lipid bilayer membranes (BLMs was quantified for protocols using hexafluoroisopropanol (HFIP or sodium hydroxide (NaOH as solvents prior to initiating the oligomer formation. Regardless of the solvent used Aβ(1-42 samples contained oligomers that reacted with the conformation-specific antibodies A11 and OC and had similar size distributions as determined by dynamic light scattering. Patch-clamp recordings of the potassium currents showed that synthetic Aβ(1-42 oligomers accelerate the activation and inactivation kinetics of Kv 1.3 current with no significant effect on current amplitude. In contrast to oligomeric samples, freshly prepared, presumably monomeric, Aβ(1-42 solutions had no effect on Kv 1.3 channel properties. Aβ(1-42 oligomers had no effect on the steady-state current (at -80 mV recorded from Kv 1.3-expressing cells but increased the conductance of artificial BLMs in a dose-dependent fashion. Formation of amyloid channels, however, was not observed due to conditions of the experiments. To exclude the effects of HFIP (used to dissolve lyophilized Aβ(1-42 peptide, and trifluoroacetic acid (TFA (used during Aβ(1-42 synthesis, we determined concentrations of these fluorinated compounds in the stock Aβ(1-42 solutions by (19F NMR. After extensive evaporation, the concentration of HFIP in the 100× stock Aβ(1-42 solutions was ∼1.7 μM. The concentration of residual TFA in the 70× stock Aβ(1-42 solutions was ∼20 μM. Even at the stock concentrations neither HFIP nor TFA alone had any effect on potassium currents or BLMs. The Aβ(1-42 oligomers prepared with HFIP as solvent, however, were more potent in the electrophysiological tests, suggesting that fluorinated compounds, such as HFIP or structurally-related inhalational anesthetics, may affect Aβ(1-42 aggregation and potentially enhance ability

  17. Antioxidant Constituents of Cotoneaster melanocarpus Lodd.

    Holzer, Veronika M D; Lower-Nedza, Agnieszka D; Nandintsetseg, Myagmar; Batkhuu, Javzan; Brantner, Adelheid H

    2013-01-01

    The aim of this study was the evaluation of the antioxidant capacity of Cotoneaster melanocarpus Lodd. and the identification of antioxidant active constituents of this plant. C. melanocarpus Lodd. is a shrub indigenous to Mongolia and used in Traditional Mongolian Medicine as a styptic. Before extraction, the plant material was separated into three parts: young sterile shoots, older stems and leaves. All these parts were extracted with water, methanol, ethyl acetate, dichloromethane and hexane, successively. The methanolic extract of the sterile shoots showed the highest antioxidant activity in the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay (IC50 30.91 ± 2.97 µg/mL). This active extract was further analyzed with chromatographic methods. TLC fingerprinting and HPLC indicated the presence of the flavonol glycosides quercetin-3-O-rutinoside (rutin), quercetin-3-O-galactoside (hyperoside) and quercetin-3-O-glucoside (isoquercetin), ursolic acid as well as chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid. The findings were substantiated with LC-MS. All identified compounds have antioxidant properties and therefore contribute to the radical scavenging activity of the whole plant. PMID:26784464

  18. Antioxidant Constituents of Cotoneaster melanocarpus Lodd.

    Adelheid H. Brantner

    2013-10-01

    Full Text Available The aim of this study was the evaluation of the antioxidant capacity of Cotoneaster melanocarpus Lodd. and the identification of antioxidant active constituents of this plant. C. melanocarpus Lodd. is a shrub indigenous to Mongolia and used in Traditional Mongolian Medicine as a styptic. Before extraction, the plant material was separated into three parts: young sterile shoots, older stems and leaves. All these parts were extracted with water, methanol, ethyl acetate, dichloromethane and hexane, successively. The methanolic extract of the sterile shoots showed the highest antioxidant activity in the DPPH (2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (IC50 30.91 ± 2.97 µg/mL. This active extract was further analyzed with chromatographic methods. TLC fingerprinting and HPLC indicated the presence of the flavonol glycosides quercetin-3-O-rutinoside (rutin, quercetin-3-O-galactoside (hyperoside and quercetin-3-O-glucoside (isoquercetin, ursolic acid as well as chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid. The findings were substantiated with LC-MS. All identified compounds have antioxidant properties and therefore contribute to the radical scavenging activity of the whole plant.

  19. A synthetic analogue of melittin aggregates in large oligomers.

    John, E.; Jähnig, F

    1992-01-01

    An analogue of melittin synthesized in the group of E. T. Kaiser (DeGrado, W. F., F. J. Keźdy, and E. T. Kaiser. 1981. J. Am. Chem. Soc. 103:679-681) was investigated by Raman spectroscopy and fluorescence anisotropy decay. In water, the analogue is completely alpha-helical and aggregates in large oligomers of about 50 monomers. In vesicle membranes, it undergoes orientational fluctuations similar to melittin. The most significant difference from melittin, therefore, is the formation of strai...

  20. Structural Transitions of Solvent-Free Oligomer-Grafted Nanoparticles

    Chremos, Alexandros

    2011-09-01

    Novel structural transitions of solvent-free oligomer-grafted nanoparticles are investigated by using molecular dynamics simulations of a coarse-grained bead-spring model. Variations in core size and grafting density lead to self-assembly of the nanoparticles into a variety of distinct structures. At the boundaries between different structures, the nanoparticle systems undergo thermoreversible transitions. This structural behavior, which has not been previously reported, deviates significantly from that of simple liquids. The reversible nature of these transitions in solvent-free conditions offers new ways to control self-assembly of nanoparticles at experimentally accessible conditions. © 2011 American Physical Society.

  1. The flower-like hierarchical architectures assembled from aniline oligomers

    Zhao, Yanchai; Tomšík, Elena; Trchová, Miroslava; Stejskal, Jaroslav

    Volume 1, No1. Sumy : Sumy State University Publishing, 2012 - (Pogrebnjak, A.), 01PCN16_1-01PCN16_4 ISSN 2304-1862. [International Conference /2./ "Nanomaterials: Applications & Properties - 2012 (NAP-2012)". Alushta (UA), 17.09.2012-22.09.2012] R&D Projects: GA ČR GA202/09/1626; GA AV ČR IAA400500905; GA ČR GAP205/12/0911 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : self-assembly * anilin e * oligomers Subject RIV: CD - Macromolecular Chemistry

  2. Constituents

    Thrane, Torben

    2004-01-01

    Taking language as a special, second-order representational system, the article explores some consequences of this view for syntactico-semantic analysis, in particular for the notion of argument structure.......Taking language as a special, second-order representational system, the article explores some consequences of this view for syntactico-semantic analysis, in particular for the notion of argument structure....

  3. The Chemical Constituents and Pharmacological Actions of Cordyceps sinensis.

    Liu, Yi; Wang, Jihui; Wang, Wei; Zhang, Hanyue; Zhang, Xuelan; Han, Chunchao

    2015-01-01

    Cordyceps sinensis, also called DongChongXiaCao (winter worm, summer grass) in Chinese, is becoming increasingly popular and important in the public and scientific communities. This study summarizes the chemical constituents and their corresponding pharmacological actions of Cordyceps sinensis. Many bioactive components of Cordyceps sinensis have been extracted including nucleoside, polysaccharide, sterol, protein, amino acid, and polypeptide. In addition, these constituents' corresponding pharmacological actions were also shown in the study such as anti-inflammatory, antioxidant, antitumour, antiapoptosis, and immunomodulatory actions. Therefore can use different effects of C. sinensis against different diseases and provide reference for the study of Cordyceps sinensis in the future. PMID:25960753

  4. Amyloid oligomer structure characterization from simulations: A general method

    Nguyen, Phuong H., E-mail: phuong.nguyen@ibpc.fr [Laboratoire de Biochimie Théorique, UPR 9080, CNRS Université Denis Diderot, Sorbonne Paris Cité IBPC, 13 rue Pierre et Marie Curie, 75005 Paris (France); Li, Mai Suan [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Derreumaux, Philippe, E-mail: philippe.derreumaux@ibpc.fr [Laboratoire de Biochimie Théorique, UPR 9080, CNRS Université Denis Diderot, Sorbonne Paris Cité IBPC, 13 rue Pierre et Marie Curie, 75005 Paris (France); Institut Universitaire de France, 103 Bvd Saint-Germain, 75005 Paris (France)

    2014-03-07

    Amyloid oligomers and plaques are composed of multiple chemically identical proteins. Therefore, one of the first fundamental problems in the characterization of structures from simulations is the treatment of the degeneracy, i.e., the permutation of the molecules. Second, the intramolecular and intermolecular degrees of freedom of the various molecules must be taken into account. Currently, the well-known dihedral principal component analysis method only considers the intramolecular degrees of freedom, and other methods employing collective variables can only describe intermolecular degrees of freedom at the global level. With this in mind, we propose a general method that identifies all the structures accurately. The basis idea is that the intramolecular and intermolecular states are described in terms of combinations of single-molecule and double-molecule states, respectively, and the overall structures of oligomers are the product basis of the intramolecular and intermolecular states. This way, the degeneracy is automatically avoided. The method is illustrated on the conformational ensemble of the tetramer of the Alzheimer's peptide Aβ{sub 9−40}, resulting from two atomistic molecular dynamics simulations in explicit solvent, each of 200 ns, starting from two distinct structures.

  5. Acidic pH retards the fibrillization of human islet amyloid polypeptide due to electrostatic repulsion of histidines

    Li, Yang; Xu, Weixin; Mu, Yuguang; Zhang, John Z. H.

    2013-08-01

    The human Islet Amyloid Polypeptide (hIAPP) is the major constituent of amyloid deposits in pancreatic islets of type-II diabetes. IAPP is secreted together with insulin from the acidic secretory granules at a low pH of approximately 5.5 to the extracellular environment at a neutral pH. The increased accumulation of extracellular hIAPP in diabetes indicates that changes in pH may promote amyloid formation. To gain insights and underlying mechanisms of the pH effect on hIAPP fibrillogenesis, all-atom molecular dynamics simulations in explicit solvent model were performed to study the structural properties of five hIAPP protofibrillar oligomers, under acidic and neutral pH, respectively. In consistent with experimental findings, simulation results show that acidic pH is not conducive to the structural stability of these oligomers. This provides a direct evidence for a recent experiment [L. Khemtemourian, E. Domenech, J. P. F. Doux, M. C. Koorengevel, and J. A. Killian, J. Am. Chem. Soc. 133, 15598 (2011)], 10.1021/ja205007j, which suggests that acidic pH inhibits the fibril formation of hIAPP. In addition, a complementary coarse-grained simulation shows the repulsive electrostatic interactions among charged His18 residues slow down the dimerization process of hIAPP by twofold. Besides, our all-atom simulations reveal acidic pH mainly affects the local structure around residue His18 by destroying the surrounding hydrogen-bonding network, due to the repulsive interactions between protonated interchain His18 residues at acidic pH. It is also disclosed that the local interactions nearby His18 operating between adjacent β-strands trigger the structural transition, which gives hints to the experimental findings that the rate of hIAPP fibril formation and the morphologies of the fibrillar structures are strongly pH-dependent.

  6. Oligomer Formation Reactions of Criegee Intermediates in the Ozonolysis of Small Unsaturated Hydrocarbons

    Sakamoto, Y.; Inomata, S.; Hirokawa, J.

    2013-12-01

    Secondary organic aerosol (SOA) constitutes a substantial fraction of atmospheric fine particulate matters and has an effect on visibility, climate and human health. One of the major oxidizing processes leading to SOA formation is an ozonolysis of unsaturated hydrocarbons (UHCs).[1] Despite of its importance, the contribution of the ozonolysis of UHCs to the SOA formation in the troposphere is not sufficiently understood due to a lack of information on reaction pathways to produce low volatile compounds. While many studies have previously been focused on SOA formation from the ozonolysis of large UHCs, SOA formation from the ozonolysis of UHCs with less than six carbon atoms have been rarely investigated because their products are expected to be too volatile to contribute to the SOA formation. Very recently, a few studies have reported the SOA formation from the ozonolysis of such small UHCs but chemical mechanisms are still unclear. [2-4] In order to understand SOA formation from the ozonolysis of the small UHCs, this study investigated gas- and particle-phase products in laboratory experiments with a Teflon bag using a negative ion chemical ionization mass spectrometry (NI-CIMS) with chloride ion transfer for chemical ionization. This technique is suitable for analysis of compounds such as carboxylic acids and hydroperoxides expected to be produced in the ozonolysis of UHCs with less fragmentation, high selectivity, and high sensitivity. In the particle-phase analysis, SOAs collected on a PTFE filter were heated, and thermally desorbed compounds were analyzed. In the gas-phase analysis, series of peaks with an interval of a mass-to-charge ratio equal to the molecular weight of a Criegee intermediate formed in their ozonolysis were observed. These peaks were attributed to oligomeric hydroperoxides composed of Criegee intermediates as a chain unit. These oligomeric hydroperoxides were also observed in the particle-phase analysis, indicating that the oligomeric

  7. Tau oligomers impair memory and induce synaptic and mitochondrial dysfunction in wild-type mice

    Jackson George R

    2011-06-01

    Full Text Available Abstract Background The correlation between neurofibrillary tangles of tau and disease progression in the brains of Alzheimer's disease (AD patients remains an area of contention. Innovative data are emerging from biochemical, cell-based and transgenic mouse studies that suggest that tau oligomers, a pre-filament form of tau, may be the most toxic and pathologically significant tau aggregate. Results Here we report that oligomers of recombinant full-length human tau protein are neurotoxic in vivo after subcortical stereotaxic injection into mice. Tau oligomers impaired memory consolidation, whereas tau fibrils and monomers did not. Additionally, tau oligomers induced synaptic dysfunction by reducing the levels of synaptic vesicle-associated proteins synaptophysin and septin-11. Tau oligomers produced mitochondrial dysfunction by decreasing the levels of NADH-ubiquinone oxidoreductase (electron transport chain complex I, and activated caspase-9, which is related to the apoptotic mitochondrial pathway. Conclusions This study identifies tau oligomers as an acutely toxic tau species in vivo, and suggests that tau oligomers induce neurodegeneration by affecting mitochondrial and synaptic function, both of which are early hallmarks in AD and other tauopathies. These results open new avenues for neuroprotective intervention strategies of tauopathies by targeting tau oligomers.

  8. Chemical Constituents of Caesalpinia decapetala (Roth Alston

    Song Yang

    2013-01-01

    Full Text Available The current study targets the chemical constituents of Caesalpinia decapetala (Roth Alston and investigates the bioactivities of the isolated compounds. Fourteen known compounds were isolated using column chromatography, and structural identification was performed by physical and spectral analyses. The biological activities of the compounds were also evaluated by 3-(4,5-dimethythiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT and 2,2-diphenlyl-1-picrylhydrazyl (DPPH assays. Emodin (6, baicalein (9, and apigenin (12 displayed antitumor activities against the MGC-803 cell line, while quercetin (2, rutin (5, baicalein (9, and epicatechin (13 showed stronger DPPH scavenging activities compared with ascorbic acid. Andrographolide (1, quercetin (2, bergenin (4, rutin (5, emodin (6, betulin (7, baicalein (9, polydatin (10, salicin (11, and apigenin (12, were obtained from C. decapetala (Roth Alston for the first time.

  9. Chemical constituents from Abutilon indicum.

    Kuo, Ping-Chung; Yang, Mei-Lin; Wu, Pei-Lin; Shih, Hui-Nung; Thang, Tran Dinh; Dung, Nguyen Xuan; Wu, Tian-Shung

    2008-01-01

    The investigation on the chemical constituents of the whole plant of Abutilon indicum has resulted in the isolation of two new compounds, abutilin A (1) and (R)-N-(1'-methoxycarbonyl-2'-phenylethyl)-4-hydroxybenzamide (2), as well as 28 known compounds. The structures of the two new compounds were established on the basis of the spectroscopic analysis, and the known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literature. PMID:18636384

  10. Hanford-specific waste constituents

    This section gives an overview of the specific chemical separation problems that need to be addressed for the Hanford Site. The constituents of the waste include toxic metals, oxy-anions, sequestering agents, actinides (mainly plutonium and americium), noble metals, other radioactive materials (technetium, cesium, strontium), and organic materials. The four waste matrices in which these wastes are found are the underground storage tanks, the soils, groundwater, and decommissioned reactors and equipment

  11. Current and constituent quark masses

    It is shown how the current quark mass, engendered by the electroweak sector, gives rise to a constituent quark mass, via the Dyson-Schwinger equations. The chiral symmetry breaking phenomenon on massless QCD is thereby seen to have an implementable generalization to the situation in which the strong bare mass is non-zero. A consistent renormalization is carried out for an arbitrary covariant gauge. (author). 16 refs

  12. Chemical constituents of Amygdalus spp. oil from Iran

    Y. Amanzadeh

    2016-01-01

    Full Text Available Background and objectives: Amygdalus with a number of endemic species grow vastly in Iran. Edible sweet almond (A. communis, is cultivated in many countries due to its pharmaceutical, nutritional and cosmetic importance; while almond oil which is rich in oleic acid is known for its economic interest. In the present study, the amount and constituents of oil of six Amygdalus species including A. communis, A. Iranshahrii, A. scoparia, A. lycioides, A. reticulata  and A. elaeagnifolia have been analyzed. Methods: The oil of the plants fruits were obtained with hot and cold methods using n-hexane and their percentages were compared. Then, the oils were analysed by GC after methylation of their constituents. Results: The results demonstrated that the hot method gave higher oil yield than cold method. The amounts of the species oils were almost similar except for A. Iranshahrii which contained the least amount of the oil. The most dominant constituents of the oils comprised of palmitic, stearic, oleic and linoleic acids with almost the same pattern, consisting of mostly oleic acid followed by linoleic and palmitic acids. In all samples only little amounts of stearic acid was detectable. Conclusion: Considering the results of the present study, the evaluated species are of high economic value and could be used as alternatives to sweet almond in pharmaceutical, nutritional and cosmetic industries.

  13. The Role of Amyloid-β Oligomers in Toxicity, Propagation, and Immunotherapy

    Sengupta, Urmi; Nilson, Ashley N.; Kayed, Rakez

    2016-01-01

    The incidence of Alzheimer's disease (AD) is growing every day and finding an effective treatment is becoming more vital. Amyloid-β (Aβ) has been the focus of research for several decades. The recent shift in the Aβ cascade hypothesis from all Aβ to small soluble oligomeric intermediates is directing the search for therapeutics towards the toxic mediators of the disease. Targeting the most toxic oligomers may prove to be an effective treatment by preventing their spread. Specific targeting of oligomers has been shown to protect cognition in rodent models. Additionally, the heterogeneity of research on Aβ oligomers may seem contradictory until size and conformation are taken into account. In this review, we will discuss Aβ oligomers and their toxicity in relation to size and conformation as well as their influence on inflammation and the potential of Aβ oligomer immunotherapy.

  14. Measuring Single-Bond Rupture Forces Using High Electric Fields in Microfluidic Channels and DNA Oligomers as Force Tags

    Breisch, Stefanie; Gonska, Julian; Deissler, Helmut; Stelzle, Martin

    2005-01-01

    The disruption force of specific biotin-streptavidin bonds was determined using DNA oligomers as force tags. Forces were generated by an electric field acting on a biotinylated fluorescently labeled DNA oligomer. DNA oligomers were immobilized via biotin-streptavidin bonds on the walls of microfluidic channels. Channel layout and fluid-based deposition process were designed to enable well-defined localized deposition of the oligomers in a narrow gap of the microchannel. Electric fields of up ...

  15. EVALUATION OF PHYTOCHEMICAL CONSTITUENT IN CONVENTIONAL AND NON CONVENTIONAL SPECIES OF CURCUMA

    Saxena Jyoti

    2012-08-01

    Full Text Available Plants and plant based medicaments are the basis of many of the modern pharmaceutical we use today for our various aliment. Plant show medicinal properties as it contain phytochemical constituent. Phytochemical constituent are non nutritive plant chemical that have disease preventive properties .This paper reports an investigation of phytochemical constituent present in the Methanolic crude rhizome extract of conventional and non conventional Curcuma species i.e Curcuma caecia , Curcuma amada and Cucrcuma longa .The phytochemical analysis was performed to detect the presence of Carbohydrates ,Starch, Amino acid, Steroid, Tannin ,Alkaloid , Flavanoid ,Glycoside and Saponin . Presence of phytochemical constituent shows the protective and disease preventive properties of plants.

  16. Chemical constituents from the whole plant of Gaultheria itoana Hayata.

    Chen, Chung-Yi; Lin, Rong-Jyh; Huang, Jin-Cherng; Wu, Yi-Hung; Cheng, Ming-Jen; Hung, His-Chou; Lo, Wen-Li

    2009-10-01

    Two new diterpenoids, 14,18-dihydroxyabieta-8,11,13-trien-7-one (1) and 13-acetyl-14,18-dihydroxy-podocarpa-8,11,13-triene (2), together with eight known compounds, i.e., gaultheric acid (3), vanillic acid (4), 4-hydroxybenzoic acid (5), cinnamic acid (6), stearic acid (7), palmitic acid (8), beta-sitosterol (9), and stigmasterol (10), were isolated from the MeOH extract of the whole plant of Gaultheria itoana Hayata (Ericaceae). The structures of the new constituents were elucidated by spectroscopic methods (UV, IR, and 1D- and 2D-NMR) and by mass spectrometry (HR-ESI-MS). Among them, 1 and 2 were demonstrated to exhibit significant cytotoxic activity against the LNCaP cell line. PMID:19842133

  17. INNOVATION CONSTITUENT OF SUSTAINABLE DEVELOPMENT

    O. Zhylinska

    2014-06-01

    Full Text Available The paper substantiates an innovation constituent of sustainable development along with environmental, social and economic pillars of the concept. Determining of implementation details of innovation activity by J. Schumpeter is a theoretical prerequisite to understanding of innovation constituent. An innovator-entrepreneur provides a customer with an information image of 'new combinations.' The image is created by identifying customer's future needs, which outline business aims, subject and appropriate means for creating the innovation products. However, consumer choice is largely motivated by values and specific rules of behavior. The rules of consumer society that in the industrial age become the motive, morality and institution, did not consider the reproductive capabilities of the environment. This disagreement was previously presented in The Limits to Growth by the Club of Rome and was reflected in the concept of sustainable development, which gained immense significance after the report of the World Commission on Environment and Development in 1987 (Our Common Future. The study highlights importance for establishment of new social values that motivate innovators to change their thinking, comprehend their responsibility not only to consumers but also to the environment and future generations. The Rio+20 Corporate Sustainability Forum: Innovation and Collaboration for the Future We want, organized by the UN Global Compact, demonstrates the interest of entrepreneurs in practical implementation of the concept of sustainable development, through an effective innovation activity. The paper summarizes management tools for implementing business commitments to action in priority areas of ensuring sustainable development: Energy & Climate, Water & Ecosystems, Agriculture & Food, Economics & Finance of Sustainable Development, Social Development, and Urbanization & Cities. Main stages of changes in companies are outlined for making responsible

  18. Radiation-chemical hardening of phenol-formaldehyde oligomers

    Radiation-chemical hardening of phenol formaldehyde oligomers of the resol type has been studied in the presence of furfural and diallylphthalate diluents. The samples have been hardened on an electron accelerator at an electron energy of 1.0-1.1 MeV and a dose rate of 2-3 Mrad/s. The kinetics of hardening has been studied on the yield of gel fraction within the range of absorbed doses from 7 to 400 Mrad. Radiation-chemical hardening of the studied compositions is activated with sensitizers, namely, amines, metal chlorides, and heterocyclic derivatives of metals. Furfural and diallylphthalate compositions are suitable for forming glass-fibre plastic items by the wet method and coatings under the action of ionizing radiations

  19. Formation of RNA oligomers on montmorillonite: site of catalysis

    Ertem, G.; Ferris, J. P.

    1998-01-01

    Certain montmorillonites catalyze the self condensation of the 5'-phosphorimidazolide of nucleosides in pH 8 aqueous electrolyte solutions at ambient temperatures leading to formation of RNA oligomers. In order to establish the nature of the sites on montmorillonite responsible for this catalytic activity, oligomerization reactions were run with montmorillonites which had been selectively modified (I) at the edges by (a) fluoride treatment, (b) silylation, (c) metaphosphate treatment of the anion exchange sites (II) in the interlayer by (a) saturation with quaternary alkylammonium ions of increasing size, (b) aluminum polyoxo cations. High pressure liquid chromatography, HPLC, analysis of condensation products for their chain lengths and yields indicated that modification at the edges did not affect the catalytic activity to a significant extent, while blocking the interlayer strongly inhibited product formation.

  20. Diffusivities and Viscosities of Poly(ethylene oxide) Oligomers

    Hong, Bingbing

    2010-10-14

    Diffusivities and viscosities of poly(ethylene oxide) (PEO) oligomer melts with 1 to 12 repeat units have been obtained from equilibrium molecular dynamics simulations using the TraPPE-UA force field. The simulations generated diffusion coefficients with high accuracy for all of the molar masses studied, but the statistical uncertainties in the viscosity calculations were significantly larger for longer chains. There is good agreement of the calculated viscosities and densities with available experimental data, and thus, the simulations can be used to bridge gaps in the data and for extrapolations with respect to chain length, temperature, and pressure. We explored the convergence characteristics of the Green-Kubo formulas for different chain lengths and propose minimal production times required for convergence of the transport properties. The chain-length dependence of the transport properties suggests that neither Rouse nor reptation models are applicable in the short-chain regime investigated. © 2010 American Chemical Society.

  1. VCD Studies on Chiral Characters of Metal Complex Oligomers

    Hisako Sato

    2013-01-01

    Full Text Available The present article reviews the results on the application of vibrational circular dichroism (VCD spectroscopy to the study of stereochemical properties of chiral metal complexes in solution. The chiral characters reflecting on the vibrational properties of metal complexes are revealed by measurements of a series of β-diketonato complexes with the help of theoretical calculation. Attention is paid to the effects of electronic properties of a central metal ion on vibrational energy levels or low-lying electronic states. The investigation is further extended to the oligomers of β-diketonato complex units. The induction of chiral structures is confirmed by the VCD spectra when chiral inert moieties are connected with labile metal ions. These results have demonstrated how VCD spectroscopy is efficient in revealing the static and dynamic properties of mononuclear and multinuclear chiral metal complexes, which are difficult to clarify by means of other spectroscopes.

  2. Opposite translocation of long and short oligomers through a nanopore

    Getfert, Sebastian; Töws, Thomas; Reimann, Peter

    2013-06-01

    We consider elongated cylindrical particles, modeling, e.g., DNA fragments or nanorods, while they translocate under the action of an externally applied voltage through a solid state nanopore. Particular emphasis is put on the concomitant potential energy landscape encountered by the particle on its passage through the pore due to the complex interplay of various electrohydrodynamic effects beyond the realm of small Debye lengths. We find that the net potential energy difference across the membrane may be of opposite sign for short and long particles of equal diameters and charge densities (e.g., oligomers). Thermal noise thus leads to biased diffusion through the pore in opposite directions. By means of an additional membrane gate electrode it is even possible to control the specific particle length at which this transport inversion occurs.

  3. Volatile Constituents of Zhumaria Majdae

    Yazdanparst

    1993-07-01

    Full Text Available Capillary gas chromatography mass spectrometry (GC- MS analyses of a sample of essential oil of zhumaria Linalool ned by simple water distillation of the pulverized air - dired leaves and flowers of the plant indicated that Linalool and comphor are the two major constituents of the volatile oil. Sylvestrene , y -terpinene, a- Pinene, b - carene, camphene, and Epiborneol constitute the other main components of the essential oil. The GC - MS chromatogram indicated the presence of more than fifty - components in the oil, most of them were present in trace amounts. In this study, the chemical structures of twenty of these consti tuents were elucidated using GC - MS analysis.

  4. Fibre constituents of some foods.

    Rani, B; Kawatra, A

    1994-06-01

    Some plant foods viz. bottlegourd, carrot, cauliflower, cabbage, green bengalgram, pea, apple, plum, guava, karonda, blackgram husk and lentil husk were analysed for their dietary fibre components. The total dietary fibre contents of these foods varied from 14.68 to 78.21 percent on dry matter basis. As compared to fruits and vegetables, the husks had higher amount of total dietary fibre. Cellulose represented as the major fibre constituent in most of the foods whereas, husks were observed to be good sources of hemicellulose. All foods were low in pectin and lignin contents except guava. PMID:7971775

  5. Characteristics of Amyloid-Related Oligomers Revealed by Crystal Structures of Macrocyclic [beta]-Sheet Mimics

    Liu, Cong; Sawaya, Michael R.; Cheng, Pin-Nan; Zheng, Jing; Nowick, James S.; Eisenberg, David (UCI); (UCLA)

    2011-09-20

    Protein amyloid oligomers have been strongly linked to amyloid diseases and can be intermediates to amyloid fibers. {beta}-Sheets have been identified in amyloid oligomers. However, because of their transient and highly polymorphic properties, the details of their self-association remain elusive. Here we explore oligomer structure using a model system: macrocyclic peptides. Key amyloidogenic sequences from A{beta} and tau were incorporated into macrocycles, thereby restraining them to {beta}-strands, but limiting the growth of the oligomers so they may crystallize and cannot fibrillate. We determined the atomic structures for four such oligomers, and all four reveal tetrameric interfaces in which {beta}-sheet dimers pair together by highly complementary, dry interfaces, analogous to steric zippers found in fibers, suggesting a common structure for amyloid oligomers and fibers. In amyloid fibers, the axes of the paired sheets are either parallel or antiparallel, whereas the oligomeric interfaces display a variety of sheet-to-sheet pairing angles, offering a structural explanation for the heterogeneity of amyloid oligomers.

  6. The case for soluble Aβ oligomers as a drug target in Alzheimer's disease.

    Hefti, Franz; Goure, William F; Jerecic, Jasna; Iverson, Kent S; Walicke, Patricia A; Krafft, Grant A

    2013-05-01

    Soluble Aβ oligomers are now widely recognized as key pathogenic structures in Alzheimer's disease. They inhibit synaptic function, leading to early memory deficits and synaptic degeneration, and they trigger the downstream neuronal signaling responsible for phospho-tau Alzheimer's pathology. The marginal effects observed in recent clinical studies of solanezumab, targeting monomeric Aβ, and bapineuzumab, targeting amyloid plaques, prompted expert comments that drug discovery efforts in Alzheimer's disease should focus on soluble forms of Aβ rather than fibrillar Aβ deposits found in amyloid plaques. Accumulating scientific data suggest that soluble Aβ oligomers represent the optimal intervention target within the amyloid manifold. Active drug discovery approaches include antibodies that selectively capture soluble Aβ oligomers, selective modifiers of oligomer assembly, and receptor antagonists. The onset of symptomatic clinical benefit is expected to be rapid for such agents, because neuronal memory signaling should normalize on blockage of soluble Aβ oligomers. This key feature is not shared by amyloid-lowering therapeutics, and it should translate into streamlined clinical development for oligomer-targeting drugs. Oligomer-targeting drugs should also confer long-term disease modification and slowing of disease progression, because they prevent the downstream signaling responsible for phospho-tau mediated cytoskeletal degeneration. PMID:23582316

  7. Fluorene- and benzofluorene-cored oligomers as low threshold and high gain amplifying media

    Kazlauskas, Karolis, E-mail: karolis.kazlauskas@ff.vu.lt; Kreiza, Gediminas; Bobrovas, Olegas; Adomėnienė, Ona; Adomėnas, Povilas; Juršėnas, Saulius [Institute of Applied Research, Vilnius University, Saulėtekio 9-III, LT-10222 Vilnius (Lithuania); Jankauskas, Vygintas [Department of Solid State Electronics, Vilnius University, Saulėtekio 9-III, LT-10222 Vilnius (Lithuania)

    2015-07-27

    Deliberate control of intermolecular interactions in fluorene- and benzofluorene-cored oligomers was attempted via introduction of different-length alkyl moieties to attain high emission amplification and low amplified spontaneous emission (ASE) threshold at high oligomer concentrations. Containing fluorenyl peripheral groups decorated with different-length alkyl moieties, the oligomers were found to express weak concentration quenching of emission, yet excellent carrier drift mobilities (close to 10{sup −2} cm{sup 2}/V/s) in the amorphous films. Owing to the larger radiative decay rates (>1.0 × 10{sup 9 }s{sup −1}) and smaller concentration quenching, fluorene-cored oligomers exhibited down to one order of magnitude lower ASE thresholds at higher concentrations as compared to those of benzofluorene counterparts. The lowest threshold (300 W/cm{sup 2}) obtained for the fluorene-cored oligomers at the concentration of 50 wt % in polymer matrix is among the lowest reported for solution-processed amorphous films in ambient conditions, what makes the oligomers promising for lasing application. Great potential in emission amplification was confirmed by high maximum net gain (77 cm{sup −1}) revealed for these compounds. Although the photostability of the oligomers was affected by photo-oxidation, it was found to be comparable to that of various organic lasing materials including some commercial laser dyes evaluated under similar excitation conditions.

  8. Small protease sensitive oligomers of PrPSc in distinct human prions determine conversion rate of PrP(C.

    Chae Kim

    Full Text Available The mammalian prions replicate by converting cellular prion protein (PrP(C into pathogenic conformational isoform (PrP(Sc. Variations in prions, which cause different disease phenotypes, are referred to as strains. The mechanism of high-fidelity replication of prion strains in the absence of nucleic acid remains unsolved. We investigated the impact of different conformational characteristics of PrP(Sc on conversion of PrP(C in vitro using PrP(Sc seeds from the most frequent human prion disease worldwide, the Creutzfeldt-Jakob disease (sCJD. The conversion potency of a broad spectrum of distinct sCJD prions was governed by the level, conformation, and stability of small oligomers of the protease-sensitive (s PrP(Sc. The smallest most potent prions present in sCJD brains were composed only of∼20 monomers of PrP(Sc. The tight correlation between conversion potency of small oligomers of human sPrP(Sc observed in vitro and duration of the disease suggests that sPrP(Sc conformers are an important determinant of prion strain characteristics that control the progression rate of the disease.

  9. Modelling Ser129 phosphorylation inhibits membrane binding of pore-forming alpha-synuclein oligomers.

    Georg Sebastian Nübling

    Full Text Available BACKGROUND: In several neurodegenerative diseases, hyperphosphorylation at position Ser129 is found in fibrillar deposits of alpha-synuclein (asyn, implying a pathophysiological role of asyn phosphorylation in neurodegeneration. However, recent animal models applying asyn phosphorylation mimics demonstrated a protective effect of phosphorylation. Since metal-ion induced asyn oligomers were identified as a potential neurotoxic aggregate species with membrane pore-forming abilities, the current study was undertaken to determine effects of asyn phosphorylation on oligomer membrane binding. METHODS: We investigated the influence of S129 phosphorylation on interactions of metal-ion induced asyn oligomers with small unilamellar lipid vesicles (SUV composed of POPC and DPPC applying the phosphorylation mimic asyn129E. Confocal single-particle fluorescence techniques were used to monitor membrane binding at the single-particle level. RESULTS: Binding of asyn129E monomers to gel-state membranes (DPPC-SUV is slightly reduced compared to wild-type asyn, while no interactions with membranes in the liquid-crystalline state (POPC-SUV are seen for both asyn and asyn129E. Conversely, metal-ion induced oligomer formation is markedly increased in asyn129E. Surprisingly, membrane binding to POPC-SUV is nearly absent in Fe(3+ induced asyn129E oligomers and markedly reduced in Al(3+ induced oligomers. CONCLUSION: The protective effect of pseudophosphorylation seen in animal models may be due to impeded oligomer membrane binding. Phosphorylation at Ser129 may thus have a protective effect against neurotoxic asyn oligomers by preventing oligomer membrane binding and disruption of the cellular electrophysiological equilibrium. Importantly, these findings put a new complexion on experimental pharmaceutical interventions against POLO-2 kinase.

  10. Conformational stability of fibrillar amyloid-beta oligomers via protofilament pair formation - a systematic computational study.

    Anna Kahler

    Full Text Available Amyloid-[Formula: see text] (A[Formula: see text] oligomers play a crucial role in Alzheimer's disease due to their neurotoxic aggregation properties. Fibrillar A[Formula: see text] oligomerization can lead to protofilaments and protofilament pairs via oligomer elongation and oligomer association, respectively. Small fibrillar oligomers adopt the protofilament topology, whereas fibrils contain at least protofilament pairs. To date, the underlying growth mechanism from oligomers to the mature fibril still remains to be elucidated. Here, we performed all-atom molecular dynamics simulations in explicit solvent on single layer-like protofilaments and fibril-like protofilament pairs of different size ranging from the tetramer to the 48-mer. We found that the initial U-shaped topology per monomer is maintained over time in all oligomers. The observed deviations of protofilaments from the starting structure increase significantly with size due to the twisting of the in-register parallel [Formula: see text]-sheets. This twist causes long protofilaments to be unstable and leads to a breakage. Protofilament pairs, which are stabilized by a hydrophobic interface, exhibit more fibril-like properties such as the overall structure and the twist angle. Thus, they can act as stable conformational templates for further fibril growth. Key properties like the twist angle, shape complementarity, and energetics show a size-dependent behavior so that small oligomers favor the protofilament topology, whereas large oligomers favor the protofilament pair topology. The region for this conformational transition is at the size of approximately twelve A[Formula: see text] monomers. From that, we propose the following growth mechanism from A[Formula: see text] oligomers to fibrils: (1 elongation of short protofilaments; (2 breakage of large protofilaments; (3 formation of short protofilament pairs; and (4 elongation of protofilament pairs.

  11. Research Progress on Chemical Constituents of Lonicerae japonicae flos

    Wang, Lingna; Jiang, Qiu; Hu, Jinghong; Zhang, Yongqing; Li, Jia

    2016-01-01

    Lonicerae japonicae flos is commonly used in traditional Chinese medicine for thousands of years with confirmed curative effects. Except for medicine, it is also used in healthy food, cosmetics, and soft beverages for its specific activities. Therefore, the chemical constituents, mainly including organic acids, flavonoids, iridoids, triterpenoids, and volatile oils, have been well studied by many scholars in recent years and a comprehensive and systematic review on chemical constituents of Lonicerae japonicae flos is indispensable. This paper aims at reviewing the chemical components of LJF in recent years through searching for the literatures both at home and abroad. Our results show that 212 components have been isolated from Lonicerae japonicae flos, including 27 flavonoids, 40 organic acids, 83 iridoids, 17 triterpenoids, and 45 other compounds, which could lay a foundation for the further application of Lonicerae japonicae flos. PMID:27403439

  12. Antiplasmodial constituents of Cajanus cajan.

    Duker-Eshun, George; Jaroszewski, Jerzy W; Asomaning, William A; Oppong-Boachie, Francis; Brøgger Christensen, S

    2004-02-01

    Bioactivity-guided fractionation of extracts of roots and leaves of Cajanus cajan afforded 8 compounds: betulinic acid, biochanin A, cajanol, genistein and 2'-hydroxygenistein, longistylin A and C, and pinostrobin. The two stilbenes, longistylin A and C, and betulinic acid showed a moderately high in vitro activity against the chloroquine-sensitive Plasmodium falciparum strain 3D7. PMID:15022164

  13. Analysis of fatty acid constituents in seed oil of Althaea rosea (L.) Caven by GC-MS%蜀葵种油的脂肪酸组成分析

    张学杰; 程传格; 李法曾

    2003-01-01

    The seed oil from Althaea rosea (L.) Caven was extracted with Hexane.After saponification and formation,the oil was determined by Capillary GC-MS.16 compounds have been determined and its unsaturation is 72.59%,Among them the content of linoleic acid is 69.24%.

  14. Isolation and identification of chemical constituents from acid hydrolyzed extract of kernel of Castanea mollissima Blume%板栗种仁酸水解物化学成分的分离与鉴定

    江冰娅; 吴兆华; 黄健; 高慧媛; 王喆星; 吴立军

    2009-01-01

    目的 更好地开发利用板栗(Castanea mollissima Blum)种仁.方法 对板栗种仁的体积分数为95%的乙醇提取物进行酸水解,水解物采用硅胶柱色谱、氧化铝柱色谱、凝胶柱色谱和重结晶等方法进行分离;根据理化性质和NMR谱数据并参考文献鉴定其结构.结果 分离鉴定了10个化合物,分别为对羟基苯甲酸(p-hydroxybenzoic acid,1)、原儿茶酸(protocatechuic acid,2)、没食子酸(gallic acid,3)、5 -羟甲基糠醛(5-hydroxymethylfurfural,4)、β-谷甾醇(β-sitosterol,5)、α-菠甾醇(α-spinasterol,6)、齐墩果酸(oleanane acid,7)、2α-羟基齐墩果酸(maslinic acid,8)、α-香树脂醇(α-amyrin,9)、单棕榈酸甘油酯(glycerolmonopalmitate,10).结论 化合物6、8为首次从栗属植物中分离得到;化合物9为首次从板栗中分离得到.

  15. The Chemical Constituents and Pharmacological Actions of Cordyceps sinensis

    Yi Liu; Jihui Wang; Wei Wang; Hanyue Zhang; Xuelan Zhang; Chunchao Han

    2015-01-01

    Cordyceps sinensis, also called DongChongXiaCao (winter worm, summer grass) in Chinese, is becoming increasingly popular and important in the public and scientific communities. This study summarizes the chemical constituents and their corresponding pharmacological actions of Cordyceps sinensis. Many bioactive components of Cordyceps sinensis have been extracted including nucleoside, polysaccharide, sterol, protein, amino acid, and polypeptide. In addition, these constituents’ corresponding ph...

  16. Novel method for isolation of major phenolic constituents from cashew (Anacardium occidentale L.) nut shell liquid.

    Paramashivappa, R; Kumar, P P; Vithayathil, P J; Rao, A S

    2001-05-01

    Commercially available cashew (Anacardium occidentale L.) nut shell liquid (CNSL) mainly contains the phenolic constituents anacardic acid, cardol, and cardanol. These phenolic constituents are themselves heterogeneous, and each of them contains saturated, monoene, diene, and trienes in the fifteen-carbon side chain. This communication describes the separation of anacardic acid, cardol, and cardanol for industrial application. Anacardic acid was selectively isolated as calcium anacardate. The acid-free CNSL was treated with liquor ammonia and extracted with hexane/ethyl acetate (98:2) to separate the mono phenolic component, cardanol. Subsequently, ammonia solution was extracted with ethyl acetate/hexane (80:20) to obtain cardol. PMID:11368634

  17. Dynamic conformations of nucleophosmin (NPM1 at a key monomer-monomer interface affect oligomer stability and interactions with granzyme B.

    Wei D Duan-Porter

    Full Text Available Nucleophosmin (NPM1 is an abundant, nucleolar tumor antigen with important roles in cell proliferation and putative contributions to oncogenesis. Wild-type NPM1 forms pentameric oligomers through interactions at the amino-terminal core domain. A truncated form of NPM1 found in some hepatocellular carcinoma tissue formed an unusually stable oligomer and showed increased susceptibility to cleavage by granzyme B. Initiation of translation at the seventh methionine generated a protein (M7-NPM that shared all these properties. We used deuterium exchange mass spectrometry (DXMS to perform a detailed structural analysis of wild-type NPM1 and M7-NPM, and found dynamic conformational shifts or local "unfolding" at a specific monomer-monomer interface which included the β-hairpin "latch." We tested the importance of interactions at the β-hairpin "latch" by replacing a conserved tyrosine in the middle of the β-hairpin loop with glutamic acid, generating Y67E-NPM. Y67E-NPM did not form stable oligomers and further, prevented wild-type NPM1 oligomerization in a dominant-negative fashion, supporting the critical role of the β-hairpin "latch" in monomer-monomer interactions. Also, we show preferential cleavage by granzyme B at one of two available aspartates (either D161 or D122 in M7-NPM and Y67E-NPM, whereas wild-type NPM1 was cleaved at both sites. Thus, we observed a correlation between the propensity to form oligomers and granzyme B cleavage site selection in nucleophosmin proteins, suggesting that a small change at an important monomer-monomer interface can affect conformational shifts and impact protein-protein interactions.

  18. Dependence of tunneling current through a single molecule of phenylene oligomers on the molecular length.

    Wakamatsu, Satoshi; Fujii, Shintaro; Akiba, Uichi; Fujihira, Masamichi

    2003-01-01

    The electrical properties of single phenylene oligomers were studied in terms of the dependence of the tunneling current on the length of the oligomers using self-assembling techniques and scanning tunneling microscopy (STM). It is important to isolate single molecules in an insulating matrix for the measurement of the conductivity of the single molecule. We demonstrate here a novel self-assembled monolayer (SAM) matrix appropriate for isolation of the single molecules. A bicyclo[2.2.2]octane derivative was used for a SAM matrix, in which the single molecules were inserted at molecular lattice defects. The isolated single molecules of phenylene oligomers inserted in the SAM matrix were observed as protrusions in STM topography using a constant current mode. We measured the topographic heights of the molecular protrusions using STM and estimated the decay constant, beta, of the tunneling current through the single phenylene oligomers using a bilayer tunnel junction model. PMID:12801653

  19. Charge transport and dielectric relaxation processes in anilin-based oligomers

    Mrlík, M.; Moučka, R.; Ilčíková, M.; Bober, Patrycja; Kazantseva, N.; Špitálský, Z.; Trchová, Miroslava; Stejskal, Jaroslav

    2014-01-01

    Roč. 192, June (2014), s. 37-42. ISSN 0379-6779 Institutional support: RVO:61389013 Keywords : anilin e-based oligomers * conductivity * dielectric properties Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.252, year: 2014

  20. Chemical Constituents of Acanthochlamys bracteata

    李帮经; 高宝莼; 彭树林; 廖循; 丁立生

    2005-01-01

    A novel nortriterpene, acanthochlamic acid (6), along with 18 known compounds has been isolated from the whole plants of Acanthochlamys bracteata P. C. Kao, a single species in family Acanthochlamydaceae which is endemic to the southwest of China. The structure of the novel nortriterpene was elucidated as 3,4-seco-3-norlup-4(23),20(29)-dien-2,28-dioic acid by spectroscopic techniques including 1D and 2D NMR spectroscopy and confirmed by X-ray crystallography.

  1. Transient dichroism in photoreceptor membranes indicates that stable oligomers of rhodopsin do not form during excitation.

    Downer, N W; Cone, R A

    1985-01-01

    If a photoexcited rhodopsin molecule initiates the formation of rhodopsin oligomers during the process of visual excitation, the rate of rotational diffusion of the rhodopsin molecules involved should change markedly. Using microsecond-flash photometry, we have observed the rotational diffusion of rhodopsin throughout the time period of visual excitation and found that no detectable change occurs in its rotational diffusion rate. Partial chemical cross-linking of the retina yields oligomers o...

  2. Modelling the size-dependence effects on the electronic properties of conjugated oligomers

    Correia, Helena M. G.; Ramos, Marta M. D.

    2011-01-01

    Comunicação oral. Conjugated oligomers are materials that have the potential to be used in organic and hybrid electronic and optoelectronic devices as an active component. However, the electronic properties responsible for their electrical and optical behaviour are size-dependent. Here we use a self-consistent quantum molecular dynamics method to study the effect of the oligomers length at nanosize regime on the ionization potential, electron affinity, charge (electrons and holes) mobility...

  3. Effect of alkyl substituents on the adsorption of thienylenevinylene oligomers on the Si (100) surface

    Grandidier, Bruno; Stiévenard, Didier; Krzeminski, Christophe; Delerue, Christophe; Frere, Pierre; Blanchard, Phillippe; Roncali, Jean; 10.1016/S0039-6028(00)00946-8

    2012-01-01

    The adsorption of thienylenevinylene oligomers on the Si(100) surface has been investigated using scanning tunneling microscopy. The mode of substitution of the thiophene ring exerts a strong influence on the adsorption configurations and the images of the oligomer based on 3,4-dihexyl thiophene are highly voltage dependent. We discuss the influence of the alkyl chains on the adsorption process and on the appearance of the molecules in the STM images.

  4. Development of new fusion proteins for visualizing amyloid-β oligomers in vivo

    Tomoyo Ochiishi; Motomichi Doi; Kazuhiko Yamasaki; Keiko Hirose; Akira Kitamura; Takao Urabe; Nobutaka Hattori; Masataka Kinjo; Tatsuhiko Ebihara; Hideki Shimura

    2016-01-01

    The intracellular accumulation of amyloid-β (Aβ) oligomers critically contributes to disease progression in Alzheimer’s disease (AD) and can be the potential target of AD therapy. Direct observation of molecular dynamics of Aβ oligomers in vivo is key for drug discovery research, however, it has been challenging because Aβ aggregation inhibits the fluorescence from fusion proteins. Here, we developed Aβ1-42-GFP fusion proteins that are oligomerized and visualize their dynamics inside cells ev...

  5. Instability of a Class A G Protein-Coupled Receptor Oligomer Interface

    Fonseca, Jacqueline M.; Lambert, Nevin A.

    2009-01-01

    The quaternary structure of G protein-coupled receptors (GPCRs) can influence their trafficking and ability to transduce signals. GPCR oligomers are generally portrayed as long-lived entities, although the stability of these complexes has not been studied. Here we show that D2 dopamine receptor protomers interact transiently at a specific oligomer interface. Selective immobilization of cyan fluorescent protein-D2 receptors (C-D2Rs) in the plasma membrane failed to comp...

  6. Ultrarobust Thin-Film Devices from Self-Assembled Metal-Terpyridine Oligomers.

    Karipidou, Zoi; Branchi, Barbara; Sarpasan, Mustafa; Knorr, Nikolaus; Rodin, Vadim; Friederich, Pascal; Neumann, Tobias; Meded, Velimir; Rosselli, Silvia; Nelles, Gabriele; Wenzel, Wolfgang; Rampi, Maria Anita; von Wrochem, Florian

    2016-05-01

    Ultrathin molecular layers of Fe(II) -terpyridine oligomers allow the fabrication of large-area crossbar junctions by conventional electrode vapor deposition. The junctions are electrically stable for over 2.5 years and operate over a wide range of temperatures (150-360 K) and voltages (±3 V) due to the high cohesive energy and packing density of the oligomer layer. Electrical measurements reveal ideal Richardson-Shottky emission in surprising agreement with electrochemical, optical, and photoemission data. PMID:26970207

  7. Mapping eGFP Oligomer Mobility in Living Cell Nuclei

    Zwerger, Monika; Müller, Gabriele; Waldeck, Waldemar; Langowski, Jörg

    2009-01-01

    Movement of particles in cell nuclei can be affected by viscosity, directed flows, active transport, or the presence of obstacles such as the chromatin network. Here we investigate whether the mobility of small fluorescent proteins is affected by the chromatin density. Diffusion of inert fluorescent proteins was studied in living cell nuclei using fluorescence correlation spectroscopy (FCS) with a two-color confocal scanning detection system. We first present experiments exposing FCS-specific artifacts encountered in live cell studies as well as strategies to prevent them, in particular those arising from the choice of the fluorophore used for calibration of the focal volume, as well as temperature and acquisition conditions used for fluorescence fluctuation measurements. After defining the best acquisition conditions, we show for various human cell lines that the mobility of GFP varies significantly within the cell nucleus, but does not correlate with chromatin density. The intranuclear diffusional mobility strongly depends on protein size: in a series of GFP-oligomers, used as free inert fluorescent tracers, the diffusion coefficient decreased from the monomer to the tetramer much more than expected for molecules free in aqueous solution. Still, the entire intranuclear chromatin network is freely accessible for small proteins up to the size of eGFP-tetramers, regardless of the chromatin density or cell line. Even the densest chromatin regions do not exclude free eGFP-monomers or multimers. PMID:19347038

  8. Mapping eGFP oligomer mobility in living cell nuclei.

    Nicolas Dross

    Full Text Available Movement of particles in cell nuclei can be affected by viscosity, directed flows, active transport, or the presence of obstacles such as the chromatin network. Here we investigate whether the mobility of small fluorescent proteins is affected by the chromatin density. Diffusion of inert fluorescent proteins was studied in living cell nuclei using fluorescence correlation spectroscopy (FCS with a two-color confocal scanning detection system. We first present experiments exposing FCS-specific artifacts encountered in live cell studies as well as strategies to prevent them, in particular those arising from the choice of the fluorophore used for calibration of the focal volume, as well as temperature and acquisition conditions used for fluorescence fluctuation measurements. After defining the best acquisition conditions, we show for various human cell lines that the mobility of GFP varies significantly within the cell nucleus, but does not correlate with chromatin density. The intranuclear diffusional mobility strongly depends on protein size: in a series of GFP-oligomers, used as free inert fluorescent tracers, the diffusion coefficient decreased from the monomer to the tetramer much more than expected for molecules free in aqueous solution. Still, the entire intranuclear chromatin network is freely accessible for small proteins up to the size of eGFP-tetramers, regardless of the chromatin density or cell line. Even the densest chromatin regions do not exclude free eGFP-monomers or multimers.

  9. Synthesis and Characterization of Poly (Arylene Ether Benzimidazole) Oligomers

    Leonard, Michael J.

    1995-01-01

    Several poly(arylene ether benzimidazole) oligomers were prepared by the nucleophilic aromatic substitution reaction of a bisphenol benzimidazole and various alkyl-substituted aromatic bisphenols with an activated aromatic dihalide in N, N-dimethylacetarnide. Moderate to high molecular weight terpolymers were obtained in all cases, as shown by their inherent viscosities, which ranged from 0.50 to 0.87 dL g(sup -1). Glass transition temperatures (T(sub g)s) of polymer powders ranged from 267-280 C. Air-dried unoriented thin film T(sub g)s were markedly lower than those of the powders, whereas T(sub g)s of films dried in a nitrogen atmosphere were identical to those of the corresponding powders. In addition, air-dried films were dark amber and brittle, whereas nitrogen-dried films were yellow and creasable. Nitrogen-dried films showed slightly higher thin-film tensile properties than the air-dried films, as well.

  10. Antidiabetic activity of the chemical constituents of Combretum dolichopetalum root in mice

    Uzor, Philip F.; Osadebe, Patience O.

    2016-01-01

    The root of Combretum dolichopetalum (Combreatacea) is used in ethnomedicine for the management of diabetes mellitus. Though some compounds have been isolated from it, the antidiabetic principles have not been identified. The present study was designed to evaluate the chemical constituents from the root of C. dolichopetalum with a view to identifying the antidiabetic principles. The constituents include the alkaloids, echinulin (1) and arestrictin B (2), the terpenoids, arjunolic acid (3) and 4'-dihydrophaseic acid (4) as well as the phenolic acids, ellagic acid (5) and 3, 4, 3'-tri-O-methylellagic acid (6). Twenty eight mice (in seven groups, n = 4) were made diabetic using alloxan monohydrate (i.p., 120 mg/kg) and treated orally with either the vehicle (control group), any of the constituents or glibenclamide (standard drug). The fasting blood glucose of the diabetic animals was monitored for nine hours. Results showed that all the chemical constituents (1-6) exhibited significant (p < 0.05) antidiabetic activity comparable to glibenclamide. The alkaloids exhibited the most profound antidiabetic activity. The present study has thus identified the antidiabetic principles of C. dolichopetalum root as echinulin, arestrictin B, arjunolic acid, 4'-dihydrophaseic acid, ellagic acid and 3, 4, 3'-tri-O-methylellagic acid. The study has further validated the ethnomedicinal use of the root of C. dolichopetalum in diabetes. PMID:27298614

  11. [Chemical constituents from Euphorbia lunulata].

    Zhao, Ming; Wu, Shuang; Li, Jun; Tang, Wan-Xia; Wang, Jin-Lan; Zhang, Shu-Jun

    2014-06-01

    The chemical constituents from Euphorbia lunulata was investigated in this paper. Fourteen compounds were isolated and purified by column chromatographies on silica gel and preparative HPLC. Their structures were identified by physiochemical properties and NMR data analysis as lupeol (1), euphol (2), cassipourol(3) , 24-methylenecycloartan-3beta-ol (4), 24-hydroperoxycycloart-25-en-3beta-ol (5), 25-hydroperoxycycloart-23-en-3beta-ol (6), betulin (7), uvaol (8), (23E) -25-methoxycycloart-23-en-3beta-ol (9), (23E) -cycloart-23,25-dien-3beta-ol (10), 24-methylenecycloartan-3beta, 28-diol (11), salicinolide (12), 2alpha, 3beta, 5alpha, 9alpha, 15beta-pentaacetoxy-11,12-epoxy-7beta, 8alpha-diisobutyryloxyjatropha-6 (17) -en-14-one (13) and 3beta, 5alpha, 15beta-triacetoxy-7beta-isobutyryloxy-9alpha-nicotinoyloxyjatropha-6 (17), 11(E)-dien-14-one (14). Among them, compounds 1-11 were isolated from E. lunulata for the first time. PMID:25244761

  12. Constituents of Nepeta crassifolia (Lamiaceae)

    ALI, Syed Amir IBRAHIM and Muhammad Shaiq

    2007-01-01

    A long chain ketone (crassifone), a pentacyclic triterpenoid coupled with fatty acid moiety (crassifoate), and an acyclic diterpenoid (crassifol) have been isolated from the ethanol soluble part of Nepeta crassifolia (Lamiaceae) collected from Kangavar, Iran. Structures of all the metabolites were elucidated with the aid of spectroscopic techniques, including 2D NMR experiments.

  13. Monitoring degradation of oil sands constituents and foodweb dynamics in aquatic reclamation using stable isotopes

    Farwell, A.J.; Butler, B.J.; Dixon, D.G. [Waterloo Univ., ON (Canada). Dept. of Biology; Mackinnon, M.D. [Syncrude Canada Ltd., Edmonton, AB (Canada)

    2003-07-01

    The process of extracting bitumen from the Athabasca oil sands deposits in northern Alberta generates large volumes of process-affected water with highly toxic constituents such as naphthenic acids. Napthenic acids can biodegrade and become less toxic in reclaimed aquatic systems. This study used stable isotopes to examine the cycling of oil sands constituents in aquatic systems. Benthic invertebrates were collected from test pits at Syncrude Canada Ltd. Dragonflies and damselflies showed trends in carbon 13 depletion and nitrogen 15 enrichment in pits with high levels of process-affected water. Chironomids and amphipods showed only nitrogen 15 enrichment. Carbon 13 depletion suggests invertebrate assimilation and incorporation of oil sands constituents through the microbial foodweb. It is important to define the isotope pathway of naphthenic acid degradation because naphthenic acids could represent a major source of carbon in reclaimed systems.

  14. Constituency Leadership: A Model for School Leaders.

    Strodl, Peter

    Principals must integrate information originating from many sectors among the schools' constituents. The degree to which constituent groups participate in school activities helps determine the quality of instruction and learning. Crucial to the role of administrator is a network of interactions between people and things, school board pressures and…

  15. Radiation damage to DNA constituents

    The molecular changes of the DNA molecule, in various systems exposed to inoizing radiation, have been the subject of a great number of studies. In the present work electron spin resonance spectroscopy (ESR) has been applied to irradiated crystalline systems, in particular single crystals of DNA subunits and their derivatives. The main conclusions about the molecular damage are based on this technique in combination with molecular orbital calculations. It should be emphasized that the ESR technique is restricted to damage containing unpaired electrons. These unstable intermediates called free radicals seem, however, to be involved in all molecular models describing the action of radiation on DNA. One of the premises for a detailed theory of the radiation induced reactions at the physico-chemical level seems to involve exact knowledge of the induced free radicals as well as the modes of their formation and fate. For DNA, as such, it is hardly possible to arrive at such a level of knowledge since the molecular complexity prevents selective studies of the many different radiation induced products. One possible approach is to study the free radicals formed in the constituents of DNA. In the present work three lines of approach should be mentioned. The first is based on the observation that radical formation in general causes only minor structural alterations to the molecule in question. The use of isotopes with different spin and magnetic moment (in particular deuterium) may also serve a source of information. Deuteration leads to a number of protons, mainly NH - and OH, becoming substituted, and if any of these are involved in interactions with unpaired protons the resonance pattern is influeneed. The third source of information is molecular orbital calculation. The electron spin density distribution is a function in the three dimensional space based on the system's electronic wave functions. This constitutes the basis for the idea that ESR data can be correlated with

  16. Novel Enzymatic Synthesis of 3-hydroxybutyric Acid Oligomerswith Inserted Lactobionic Acid Moieties

    Kakasi-Zsurka, S.; Todea, A.; But, A.; PAUL, C; Boeriu, C.G.; Nagv, A.; Davidescu, C.M.; Peter, F

    2011-01-01

    3-Hydroxybutyric acid and lactobionic acid yielded linear and cyclic oligomers in a lipase-catalyzedcondensation polymerization reaction, performed at 80°C in bulk and organic solvent systems. Novozyme435 was the most efficient biocatalyst, and a mixture of t-butanol and dimethylsulfoxide in 80:20 (v/v) ratioprovided the highest copolymer conversions. The highest degree of polymerization reached 7 in case ofcopolymers with inserted lactobionic acid moiety and 11 for the 3-hydroxybutyric acid ...

  17. Angiostatic effects of Brazilian green propolis and its chemical constituents.

    Chikaraishi, Yuichi; Izuta, Hiroshi; Shimazawa, Masamitsu; Mishima, Satoshi; Hara, Hideaki

    2010-04-01

    Propolis, a resinous substance collected by honeybees from various plant sources, has several pharmacological actions, such as anti-tumor and anti-inflammatory effects. The aim of this study was to evaluate the anti-angiogenic effects of a water extract of Brazilian green propolis (WEP) and its constituents, caffeoylquinic acid derivatives, against angiogenic processes in human umbilical vein endothelial cells (HUVECs) in vitro. We also examined the anti-angiogenic effects of WEP against retinal neovascularization in a murine oxygen-induced retinopathy model in vivo. WEP and its constituents significantly suppressed vascular endothelial growth factor (VEGF)-induced HUVEC proliferation, migration, and tube formation in vitro. WEP and its caffeoylquinic acid derivatives suppressed VEGF-stimulated phosphorylation of mitogen-activated protein kinase in HUVECs (versus VEGF alone). Moreover, WEP (300 mg/kg/day, subcutaneously for 5 days) significantly suppressed retinal neovascularization in the murine oxygen-induced retinopathy model. These data indicate that (i) WEP has angiostatic effects against angiogenic processes in vitro and in an in vivo model of murine oxygen-induced retinopathy and (ii) the inhibitory effects of WEP against in vitro angiogenesis are chiefly derived from its caffeoylquinic acid derivatives. Judging from these findings, WEP and its caffeoylquinic acid derivatives may represent candidates for preventive or therapeutic agents against diseases caused by angiogenesis. PMID:19960454

  18. Solvent free low-melt viscosity imide oligomers and thermosetting polymide composites

    Chuang, Chun-Hua (Inventor)

    2012-01-01

    .[.This invention relates to the composition and a solvent-free process for preparing novel imide oligomers and polymers specifically formulated with effective amounts of a dianhydride such as 2,3,3',4-biphenyltetra carboxylic dianydride (a-BPDA), at least one aromatic diamine and an endcapped of 4-phenylethynylphthalic anhydride (PEPA) or nadic anhydride to produce imide oligomers that possess a low-melt viscosity of 1-60 poise at 260-280.degree. C. When the imide oligomer melt is cured at about 371.degree. C. in a press or autoclave under 100-500 psi, the melt resulted in a thermoset polyimide having a glass transition temperature (T.sub.g) equal to and above 310.degree. C. A novel feature of this process is that the monomers; namely the dianhydrides, diamines and the endcaps, are melt processable to form imide oligomers at temperatures ranging between 232-280.degree. C. (450-535.degree. F.) without any solvent. These low-melt imide oligomers can be easily processed by resin transfer molding (RTM), vacuum-assisted resin transfer molding (VARTM) or the resin infusion process with fiber preforms e.g. carbon, glass or quartz preforms to produce polyimide matrix composites with 288-343.degree. C. (550-650.degree. F.) high temperature performance capability..]. .Iadd.This invention relates to compositions and a solvent-free reaction process for preparing imide oligomers and polymers specifically derived from effective amounts of dianhydrides such as 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), at least one aromatic polyamine and an end-cap such as 4-phenylethynyphthalic anhydride (PEPA) or nadic anhydride to produce imide oligomers that possess a low-melt viscosity of 1-60 poise at 260.degree. C.-280.degree. C..Iaddend.

  19. The Lewis acid catalyzed synthesis of hyperbranched Oligo(glycerol-diacid)s in aprotic polar media

    The Lewis-acid, titanium (IV) butoxide (15% (w/w; catalyst/reactants)), was used to catalyze the condensation of 0.05 mol glycerol with 0.10 mol of either succinic acid, glutaric acid, or azelaic acid to produce oligomers. The reactions were refluxed in dilute solutions of dimethylsulfoxide (DMSO) o...

  20. Phenolic constituents from Drypetes armoracia.

    Wandji, Jean; Tillequin, François; Mulholland, Dulcie A; Temgoua, Agathe D; Wansi, Jean-D; Seguin, Elisabeth; Fomum, Z Tanee

    2003-06-01

    The methanol extract of the dried stem bark of Drypetes armoracia Pax & Hoffm. afforded two compounds named drypearmoracein A, (E)-4,5,6,7-tetrahydroxy-2-benzylhept-2-enoic acid and drypearmoracein B, 2,3-dihydroxy-9,10-tetrahydroanthra-1,4-quinone along with five known compounds: friedelan-3 beta-ol, friedelin, friedelane-3,7-dione, drypemolundein B and beta-stigmasterol. Their structures were established on the basis of spectroscopic analysis and chemical evidence. PMID:12770597

  1. Computational design of organometallic oligomers featuring 1,3-metal-carbon bonding and planar tetracoordinate carbon atoms.

    Zhao, Xue-Feng; Yuan, Cai-Xia; Wang, Xiang; Li, Jia-Jia; Wu, Yan-Bo; Wang, Xiaotai

    2016-01-15

    Density functional theory computations (B3LYP) have been used to explore the chemistry of titanium-aromatic carbon "edge complexes" with 1,3-metal-carbon (1,3-MC) bonding between Ti and planar tetracoordinate Cβ . The titanium-coordinated, end-capping chlorides are replaced with OH or SH groups to afford two series of difunctional monomers that can undergo condensation to form oxide- and sulfide-bridged oligomers. The sulfide-linked oligomers have less molecular strain and are more exergonic than the corresponding oxide-linked oligomers. The HOMO-LUMO gap of the oligomers varies with their composition and decreases with growing oligomer chain. This theoretical study is intended to enrich 1,3-MC bonding and planar tetracoordinate carbon chemistry and provide interesting ideas to experimentalists. Organometallic complexes with the TiE2 (E = OH and SH) decoration on the edge of aromatic hydrocarbons have been computationally designed, which feature 1,3-metal-carbon (1,3-MC) bonding between titanium and planar tetracoordinate β-carbon. Condensation of these difunctional monomers by eliminating small molecules (H2O and H2S) produce chain-like oligomers. The HOMO-LUMO gaps of the oligomers decreases with growing oligomer chain, a trend that suggests possible semiconductor properties for oligomers with longer chains. PMID:26399226

  2. Prefibrillar transthyretin oligomers and cold stored native tetrameric transthyretin are cytotoxic in cell culture

    Recent studies suggest that soluble, oligomeric species, which are intermediates in the fibril formation process in amyloid disease, might be the key species in amyloid pathogenesis. Soluble oligomers of human wild type transthyretin (TTR) were produced to elucidate oligomer properties. Employing ThT fluorescence, time-resolved fluorescence anisotropy of pyrene-labeled TTR, chemical cross-linking, and electron microscopy we demonstrated that early formed soluble oligomers (within minutes) from A-state TTR comprised on the average 20-30 TTR monomers. When administered to neuroblastoma cells these early oligomers proved highly cytotoxic and induced apoptosis after 48 h of incubation. More mature fibrils (>24 h of fibrillation) were non-toxic. Surprisingly, we also found that native tetrameric TTR, when purified and stored under cold conditions (4 deg. C) was highly cytotoxic. The effect could be partially restored by increasing the temperature of the protein. The cytotoxic effects of native tetrameric TTR likely stems from a hitherto unexplored low temperature induced rearrangement of the tetramer conformation that possibly is related to the conformation of misfolded TTR in amyloigogenic oligomers.

  3. Indirect detection of ethylene glycol oligomers using a contactless conductivity detector in capillary liquid chromatography.

    Takeuchi, Toyohide; Sedyohutomo, Anang; Lim, Lee Wah

    2009-07-01

    Ethylene glycol oligomers were visualized by indirect conductimetric detection based on dilution of the mobile phase due to the analytes. A high electrical conductivity background was maintained by the addition of 5 mM sodium nitrate in the mobile phase, and the analytes were visualized by decreases in the background when they eluted. A capacitively coupled contactless conductivity detector was convenient to monitor effluents from the microcolumn with minimum extra-column band broadening. The signals as negative peaks were linear to the concentration of the analytes, and a concentration detection limit of 0.025% was achieved for tetraethylene glycol at S/N=3, corresponding to the mass detection limit of 38 ng for 0.15 microl injection. The logarithm of the retention factor of ethylene glycol oligomers was linear to the degree of polymerization (DP) as well as to the acetonitrile composition in the mobile phase. These situations allowed us to estimate the DP of eluted ethylene glycol oligomers by using a few oligomers with known DP. The dynamic reserve, defined as the ratio of the background to its noise level achieved under the present conditions, was 2.3 x 10(5) which was much larger than that achieved by UV absorption detection. The present method was applied to profile ethylene glycol oligomers contained in commercially available PEG reagents. PMID:19609021

  4. Hybrid conjugated organic oligomers consisting of oligodiacetylene and thiophene units: synthesis and optical properties.

    Pilzak, Gregor S; van Gruijthuijsen, Kitty; van Doorn, Reindert H; van Lagen, Barend; Sudhölter, Ernst J R; Zuilhof, Han

    2009-09-14

    Novel and highly soluble hybrid conjugated organic oligomers consisting of oligodiacetylene and thiophene units have been synthesized in high purity through iterative and divergent approaches based on a sequence of Sonogashira reactions. The series of thiophene-containing oligodiacetylenes (ThODAs) and homocoupled ThODAs (HThODAs) show--both in solution and in the solid state--a strong optical absorption, which is progressively red shifted with increasing chain length. The linear correlation of the absorption maximum (lambda(A)(max)) with the inverse of conjugation length (CL = number of double and triple bonds) shows that the effective conjugation length of this system is extended up to at least CL = 20. Furthermore, absorption measurements of dropcast thin films display not only a bathochromic shift of the absorption maxima but also a higher wavelength absorption, which is attributed to increased pi-pi interactions. The wavelength of the maximum fluorescence emission (lambda(E)(max)) also increases with CL, and emission is maximal for oligomers with CL=7-12 (fluorescence quantum yield Phi(F) = approximately 0.2). Both longer and shorter oligomers display marginal emission. The calculated Stokes shifts of these planar materials are relatively large (0.4 eV) for all oligomers, and likely due to excitation to the S(2) state, thus suggesting that the presence of enyne moieties dominates the ordering of the lowest excited states. The fluorescence lifetimes (tau(F)) are short (tau(F,max) = line with highly rigid oligomers. PMID:19637259

  5. Alzheimer's-associated Aβ oligomers show altered structure, immunoreactivity and synaptotoxicity with low doses of oleocanthal

    It now appears likely that soluble oligomers of amyloid-β1-42 peptide, rather than insoluble fibrils, act as the primary neurotoxin in Alzheimer's disease (AD). Consequently, compounds capable of altering the assembly state of these oligomers (referred to as ADDLs) may have potential for AD therapeutics. Phenolic compounds are of particular interest for their ability to disrupt Aβ oligomerization and reduce pathogenicity. This study has focused on oleocanthal (OC), a naturally-occurring phenolic compound found in extra-virgin olive oil. OC increased the immunoreactivity of soluble Aβ species, when assayed with both sequence- and conformation-specific Aβ antibodies, indicating changes in oligomer structure. Analysis of oligomers in the presence of OC showed an upward shift in MW and a ladder-like distribution of SDS-stable ADDL subspecies. In comparison with control ADDLs, oligomers formed in the presence of OC (Aβ-OC) showed equivalent colocalization at synapses but exhibited greater immunofluorescence as a result of increased antibody recognition. The enhanced signal at synapses was not due to increased synaptic binding, as direct detection of fluorescently-labeled ADDLs showed an overall reduction in ADDL signal in the presence of OC. Decreased binding to synapses was accompanied by significantly less synaptic deterioration assayed by drebrin loss. Additionally, treatment with OC improved antibody clearance of ADDLs. These results indicate oleocanthal is capable of altering the oligomerization state of ADDLs while protecting neurons from the synaptopathological effects of ADDLs and suggest OC as a lead compound for development in AD therapeutics.

  6. Parametrization of the Gay-Berne potential for conjugated oligomer with a high aspect ratio

    Lee, Cheng K.; Hua, Chi C.; Chen, Show A.

    2010-08-01

    The Gay-Berne (GB) potential has been a popular semiempirical model for describing the short-range intermolecular forces for a wide variety of aspherical molecules, including liquid crystals and anisotropic colloids, with generally small molecular dimensions and low aspect ratios (<5). This study evaluates the parametrization of the GB potential for a high-aspect-ratio (=10) oligomer belonging to a model conjugated polymer. We elaborate that the semiflexibility associated with a large oligomer species demands a variant umbrella-sampling scheme in establishing the potentials of mean force (PMFs) for four pair ellipsoid arrangements typically utilized to parametrize the GB potential. The model ellipsoid so constructed is shown to capture the PMFs of essential intermediate arrangements as well, and, according to the results of simplex optimizations, recommendations are given for the minimum set of parameters to be included in the optimization of a large oligomer or particulate species. To further attest the parametrized GB potential, the coarse-grained (CG) Monte Carlo simulations employing the GB potential and the back-mapped, full-atom atomistic molecular dynamics (AMD) simulations were performed for a dense oligomer system at two representative system temperatures. The results indicated that the CG simulations can capture, with exceptional computational efficiency, the AMD predictions with good thermal transferability. In future perspectives, we remark on potential applications to construct efficient, parameter-free CG models for capturing fundamental material properties of large oligomer/particulate species as well as long-chain conjugated polymers.

  7. Determination of the critical molar mass of ovalbumin oligomers degraded by ultrasound

    BRATOLJUB H. MILOSAVLJEVIC

    2000-02-01

    Full Text Available An experimental method has been developed which enables the determination of the critical molar mass (Mmc of ovalbumin oligomers degraded by ultrasound of known frequency. To test the validity of the Mmc postulate, a series of ovalbumin oligomers was prepared by the radiolytic cross-linking of 1% solutions of ovalbumin monomer dissolved in 50 mM Na/K-phosphate buffer pH 7.0 saturated with N2O. Under these conditions, irradiation with 5 kGy from a 60Co source, yielded ovalbumin dimers, trimers, tetramers, and higher order oligomers. On the basis of the results obtained with the ovalbumin oligomers, it was concluded that for ultrasound of 23 kHz frequency and 5mm amplitude, the Mmc was 274000 + 14000 g/mol. Our results confirmed that the two postulates in the chemistry of polymer degradation by ultrasound are valid when ovalbumin oligomers are used as substrates, i.e., (1 that the higher the molar mass of the original macromolecule, the faster is its degradation rate, and (2 that a lower molar mass limit (LMmL exists below which the macromolecules are resistent to further degradation.

  8. Folate: a functional food constituent.

    Iyer, Ramya; Tomar, S K

    2009-01-01

    Folate, a water-soluble vitamin, includes naturally occurring food folate and synthetic folic acid in supplements and fortified foods. Mammalian cells cannot synthesize folate and its deficiency has been implicated in a wide variety of disorders. A number of reviews have dwelt up on the health benefits associated with increased folate intakes and many countries possess mandatory folate enrichment programs. Lately, a number of studies have shown that high intakes of folic acid, the chemically synthesized form, but not natural folates, can cause adverse effects in some individuals such as the masking of the hematological manifestations of vitamin B(12) deficiency, leukemia, arthritis, bowel cancer, and ectopic pregnancies. As fermented milk products are reported to contain even higher amounts of folate produced by the food-grade bacteria, primarily lactic acid bacteria (LAB), the focus has primarily shifted toward the natural folate, that is, folate produced by LAB and levels of folate present in foods fermented by/or containing these valuable microorganisms. The proper selection and use of folate-producing microorganisms is an interesting strategy to increase "natural" folate levels in foods. An attempt has been made through this review to share information available in the literature on wide ranging aspects of folate, namely, bioavailability, analysis, deficiency, dietary requirements, and health effects of synthetic and natural folate, dairy and nondairy products as a potential source of folate, microorganisms with special reference to Streptococcus thermophilus as prolific folate producer, and recent insight on modulation of folate production levels in LAB by metabolic engineering. PMID:20492126

  9. [Chemical constituents from Spatholobus sinensis].

    Yin, Ting; Liu, Hua; Wang, Bin; Tu, Guang-Zhong; Liang, Hong; Zhao, Yu-Ying

    2008-01-01

    Spatholobus sinensis is a plant of the Spatholobus genus (Leguminosae family). Its caulis are used as "ji-xue-teng" regionally. However, to our knowledge, no phytochemical investigation on S. sinensis has been reported to date. In this study, eight compounds were isolated from the ethanol extract of the caulis of S. sinensis, by solvents extraction and column chromatography methods. By analysis of their physic-chemical constants and spectral data, the structures of 8 compounds were identified as spatholosineside A (1), 2',4',5,7-tetrahydroxyisoflavone (2), isoliquiritigenin (3), lupinalbin A (4), coumestrol (5), naringenin (6), protocatechuic acid (7), leonuriside A (8). Compound 1 is a new compound. PMID:18357735

  10. Chemical Constituents of Cordyceps cicadae.

    Chu, Zhi-Bo; Chang, Jun; Zhu, Ying; Sun, Xun

    2015-12-01

    One new bifuran derivative (1), together with fourteen known compounds, were isolated from Cordyceps cicadae X. Q. Shing. The known compounds included nine nucleosides, uracil (2), uridine (3), 2'-deoxyuridine (4), 2'-deoxyinosine (5), guanosine (6), 2'-deoxyguanosine (7), thymidine (8), adenosine (9), and 2'-deoxyadenosine (10); three amino acids tryptophan (11), phenylalanine (12), and tyrosine (13); and two dopamine analogues N-acetylnoradrenaline (14) and its dimer, trans-2-(3',4'-dihydroxyphenyl)-3-acetylamino-7-(N-acetyl-2"-amino-ethylene)-1,4-benzodioxane (15). Their structures were decisively elucidated by spectroscopic analysis, including 1D and 2D NMR techniques. PMID:26882686

  11. Chemical Constituents from Campylotropis hirtella.

    Xie, Yang-Guo; Li, Tao; Wang, Guo-Wei; Ren, Jie; Wang, Xing; Pan, Ya-Ping; Li, Hui-Liang; Yan, Shi-Kai; Jin, Hui-Zi; Zhang, Wei-Dong

    2016-05-01

    A phytochemical investigation on the roots of Campylotropis hirtella afforded nine new isoflavones (3-9, 12, 15), two new isoflavans (10 and 11), one new coumestan (1), and three new prenylated benzoic acid derivatives (2, 13, 14), together with twenty-four known compounds. Their structures were established by spectroscopic analysis and circular dichroism data. The isolated compounds were also evaluated for their antibacterial activities against Enterococcus faecalis, Salmonella gallinarum, Streptococcus suis, Streptococcus agalactiae, Aeromonas hydrophila, Pseudomonas aeruginosa, Bacillus subtilis, Riemerella anatipestifer, and Vibrio alginolyticus. PMID:27220079

  12. The MitCHAP-60 Disease Is Due to Entropic Destabilization of the Human Mitochondrial Hsp60 Oligomer*

    Parnas, Avital; Nadler, Michal; Nisemblat, Shahar; Horovitz, Amnon; Mandel, Hanna; Azem, Abdussalam

    2009-01-01

    The 60-kDa heat shock protein (mHsp60) is a vital cellular complex that mediates the folding of many of the mitochondrial proteins. Its function is executed in cooperation with the co-chaperonin, mHsp10, and requires ATP. Recently, the discovery of a new mHsp60-associated neurodegenerative disorder, MitCHAP-60 disease, has been reported. The disease is caused by a point mutation at position 3 (D3G) of the mature mitochondrial Hsp60 protein, which renders it unable to complement the deletion of the homologous bacterial protein in Escherichia coli (Magen, D., Georgopoulos, C., Bross, P., Ang, D., Segev, Y., Goldsher, D., Nemirovski, A., Shahar, E., Ravid, S., Luder, A., Heno, B., Gershoni-Baruch, R., Skorecki, K., and Mandel, H. (2008) Am. J. Hum. Genet. 83, 30–42). The molecular basis of the MitCHAP-60 disease is still unknown. In this study, we present an in vitro structural and functional analysis of the purified wild-type human mHsp60 and the MitCHAP-60 mutant. We show that the D3G mutation leads to destabilization of the mHsp60 oligomer and causes its disassembly at low protein concentrations. We also show that the mutant protein has impaired protein folding and ATPase activities. An additional mutant that lacks the first three amino acids (N-del), including Asp-3, is similarly impaired in refolding activity. Surprisingly, however, this mutant exhibits profound stabilization of its oligomeric structure. These results suggest that the D3G mutation leads to entropic destabilization of the mHsp60 oligomer, which severely impairs its chaperone function, thereby causing the disease. PMID:19706612

  13. The MitCHAP-60 disease is due to entropic destabilization of the human mitochondrial Hsp60 oligomer.

    Parnas, Avital; Nadler, Michal; Nisemblat, Shahar; Horovitz, Amnon; Mandel, Hanna; Azem, Abdussalam

    2009-10-01

    The 60-kDa heat shock protein (mHsp60) is a vital cellular complex that mediates the folding of many of the mitochondrial proteins. Its function is executed in cooperation with the co-chaperonin, mHsp10, and requires ATP. Recently, the discovery of a new mHsp60-associated neurodegenerative disorder, MitCHAP-60 disease, has been reported. The disease is caused by a point mutation at position 3 (D3G) of the mature mitochondrial Hsp60 protein, which renders it unable to complement the deletion of the homologous bacterial protein in Escherichia coli (Magen, D., Georgopoulos, C., Bross, P., Ang, D., Segev, Y., Goldsher, D., Nemirovski, A., Shahar, E., Ravid, S., Luder, A., Heno, B., Gershoni-Baruch, R., Skorecki, K., and Mandel, H. (2008) Am. J. Hum. Genet. 83, 30-42). The molecular basis of the MitCHAP-60 disease is still unknown. In this study, we present an in vitro structural and functional analysis of the purified wild-type human mHsp60 and the MitCHAP-60 mutant. We show that the D3G mutation leads to destabilization of the mHsp60 oligomer and causes its disassembly at low protein concentrations. We also show that the mutant protein has impaired protein folding and ATPase activities. An additional mutant that lacks the first three amino acids (N-del), including Asp-3, is similarly impaired in refolding activity. Surprisingly, however, this mutant exhibits profound stabilization of its oligomeric structure. These results suggest that the D3G mutation leads to entropic destabilization of the mHsp60 oligomer, which severely impairs its chaperone function, thereby causing the disease. PMID:19706612

  14. Salacia crassifolia (Celastraceae: CHEMICAL CONSTITUENTS AND ANTIMICROBIAL ACTIVITY

    Vanessa G. Rodrigues

    2015-02-01

    Full Text Available The phytochemical study of hexane extract from leaves of Salacia crassifolia resulted in the isolation of 3β-palmitoxy-urs-12-ene, 3-oxofriedelane, 3β-hydroxyfriedelane, 3-oxo-28-hydroxyfriedelane, 3-oxo-29-hydroxyfriedelane, 28,29-dihydroxyfriedelan-3-one, 3,4-seco-friedelan-3-oic acid, 3β-hydroxy-olean-9(11:12-diene and the mixture of α-amirin and β-amirin. β-sitosterol, the polymer gutta-percha, squalene and eicosanoic acid were also isolated. The chemical structures of these constituents were established by IR, 1H and 13C NMR spectral data. Crude extracts and the triterpenes were tested against Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis and no activity was observed under the in vitro assay conditions. The hexane, chloroform, ethyl acetate and ethanol crude extracts, and the constituent 3,4-seco-friedelan-3-oic acid and 28,29-dihydroxyfriedelan-3-one showed in vitro antimicrobial activity against Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Streptococcus sanguinis and Candida albicans.

  15. [GC-MS analysis of volatile constituents from five different kinds of Chinese eaglewood].

    Mei, Wen-Li; Zeng, Yan-Bo; Liu, Jun; Dai, Hao-Fu

    2007-05-01

    Volatile oils of five different kinds of Chinese eaglewood were extracted with aether at room temperature. The chemical constituents and relative contents of the volatile oils were analysed by GC-MS. It showed that all the five volatile oils were mainly composed of sesquiterpenes, aromatic constituents and fatty acids. Several sesquiterpenes, such as hinesol, nootkatone, valerenic acid, velleral, guaiol, gamma-gurjunene, gamma-selinene, viridiflorol, isoaromadendrene epoxide, valencene, alpha-costol et. al., together with several aromatic constituents, 2,4-di-tert-butylphenol,4-methyl-2,6-di-tert-butylphenol, phenylpropionic acid, 1-(benzyloxy)-8-naphthol, anisylacetone, et. al. were found in the volatile oils of Chinese eaglewood for the first time. The samilarities and differences of the volatile oils from the five kinds of Chinese eaglewood were compared. It suggested that the quality of Chinese eaglewood could be evaluated by GC-MS analyse of the volatile oil. PMID:17727060

  16. A mechanistic model of tau amyloid aggregation based on direct observation of oligomers

    Shammas, Sarah L.; Garcia, Gonzalo A.; Kumar, Satish; Kjaergaard, Magnus; Horrocks, Mathew H.; Shivji, Nadia; Mandelkow, Eva; Knowles, Tuomas P. J.; Mandelkow, Eckhard; Klenerman, David

    2015-04-01

    Protein aggregation plays a key role in neurodegenerative disease, giving rise to small oligomers that may become cytotoxic to cells. The fundamental microscopic reactions taking place during aggregation, and their rate constants, have been difficult to determine due to lack of suitable methods to identify and follow the low concentration of oligomers over time. Here we use single-molecule fluorescence to study the aggregation of the repeat domain of tau (K18), and two mutant forms linked with familial frontotemporal dementia, the deletion mutant ΔK280 and the point mutant P301L. Our kinetic analysis reveals that aggregation proceeds via monomeric assembly into small oligomers, and a subsequent slow structural conversion step before fibril formation. Using this approach, we have been able to quantitatively determine how these mutations alter the aggregation energy landscape.

  17. Oligomers of heat-shock proteins: Structures that don't imply function

    Jacobs, William M; Frenkel, Daan

    2015-01-01

    Most proteins must remain soluble in the cytosol in order to perform their biological functions. To protect against undesired protein aggregation, living cells maintain a population of molecular chaperones that ensure the solubility of the proteome. Here we report simulations of a lattice model of interacting proteins to understand how low concentrations of passive molecular chaperones, such as small heat-shock proteins, suppress thermodynamic instabilities in protein solutions. Given fixed concentrations of chaperones and client proteins, the solubility of the proteome can be increased by tuning the chaperone--client binding strength. Surprisingly, we find that the binding strength that optimizes solubility while preventing irreversible chaperone binding also promotes the formation of weakly bound chaperone oligomers, although the presence of these oligomers does not significantly affect the thermodynamic stability of the solution. Such oligomers are commonly observed in experiments on small heat-shock prote...

  18. Biodegradable polyester-based eco-composites containing hemp fibers modified with macrocyclic oligomers

    Conzatti, Lucia; Utzeri, Roberto; Hodge, Philip; Stagnaro, Paola

    2016-05-01

    An original compatibilizing pathway for hemp fibers/poly(1,4-butylene adipate-co-terephtalate) (PBAT) eco-composites was explored exploiting the capability of macrocyclic oligomers (MCOs), obtained by cyclodepolymerization (CDP) of PBAT at high dilution, of being re-converted into linear chains by entropically-driven ring-opening polymerization (ED-ROP) that occurs simply heating the MCOS in the bulk. CDP reaction of PBAT was carried out varying solvent, catalyst and reaction time. Selected MCOs were used to adjust the conditions of the ED-ROP reaction. The best experimental conditions were then adopted to modify hemp fibers. Eco-composites based on PBAT and hemp fibers as obtained or modified with PBAT macrocyclics or oligomers were prepared by different process strategies. The best fiber-PBAT compatibility was observed when the fibers were modified with PBAT oligomers before incorporation in the polyester matrix.

  19. Simple Extrapolation Method to Predict the Electronic Structure of Conjugated Polymers from Calculations on Oligomers

    Larsen, Ross E.

    2016-05-12

    We introduce two simple tight-binding models, which we call fragment frontier orbital extrapolations (FFOE), to extrapolate important electronic properties to the polymer limit using electronic structure calculations on only a few small oligomers. In particular, we demonstrate by comparison to explicit density functional theory calculations that for long oligomers the energies of the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and of the first electronic excited state are accurately described as a function of number of repeat units by a simple effective Hamiltonian parameterized from electronic structure calculations on monomers, dimers and, optionally, tetramers. For the alternating copolymer materials that currently comprise some of the most efficient polymer organic photovoltaic devices one can use these simple but rigorous models to extrapolate computed properties to the polymer limit based on calculations on a small number of low-molecular-weight oligomers.

  20. Incorporation of 14C in chemical constituents of algal cells

    Two marine algal species Dunaliella premodecta, Chlamydemonas sp. and one fresh water species Scenedesmus obliquus were studied for 14C incorporation under laboratory conditions. The uptake of 14C in dry marine algal species was found to be more compared to that in fresh water species for the same initial concentration in the respective media. A sequential extraction technique was employed to study the distribution of 14C in different organic constituents. 14C fixation was found to be more in fatty acid fractions followed by protein and nucleoprotein fraction. (author). 13 refs., 2 tabs

  1. The Chemical Constituents and Pharmacological Actions of Cordyceps sinensis

    Yi Liu

    2015-01-01

    Full Text Available Cordyceps sinensis, also called DongChongXiaCao (winter worm, summer grass in Chinese, is becoming increasingly popular and important in the public and scientific communities. This study summarizes the chemical constituents and their corresponding pharmacological actions of Cordyceps sinensis. Many bioactive components of Cordyceps sinensis have been extracted including nucleoside, polysaccharide, sterol, protein, amino acid, and polypeptide. In addition, these constituents’ corresponding pharmacological actions were also shown in the study such as anti-inflammatory, antioxidant, antitumour, antiapoptosis, and immunomodulatory actions. Therefore can use different effects of C. sinensis against different diseases and provide reference for the study of Cordyceps sinensis in the future.

  2. Constituents from Senecio scandens and their antioxidant bioactivity.

    Leu, Yann-Lii; Lin, Chih-Lung; Kuo, Ping-Chung

    2011-03-01

    Forty-one compounds including two new constituents, senecainin A (1) and 3-methoxyisonicotinic acid (2), were characterized from the methanol extracts of the whole plant of Senecio scandens. The structures of the new compounds were comprehensively established with the aid of 1D and 2D NMR spectroscopic and mass spectrometric analyses. The chemical structures of known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literature. In addition, the antioxidant activity of some of the isolates was examined in the DPPH free radical scavenging assay. Among the tested compounds, (-)-monoepoxylignanolide, (-)-pinoresinol and (-)-epi-pinoresinol displayed significant antioxidant bioactivity. PMID:21547668

  3. Molecular insight into amyloid oligomer destabilizing mechanism of flavonoid derivative 2-(4' benzyloxyphenyl)-3-hydroxy-chromen-4-one through docking and molecular dynamics simulations.

    Kumar, Akhil; Srivastava, Swati; Tripathi, Shubhandra; Singh, Sandeep Kumar; Srikrishna, Saripella; Sharma, Ashok

    2016-06-01

    Aggregation of amyloid peptide (Aβ) has been shown to be directly related to progression of Alzheimer's disease (AD). Aβ is neurotoxic and its deposition and aggregation ultimately lead to cell death. In our previous work, we reported flavonoid derivative (compound 1) showing promising result in transgenic AD model of Drosophila. Compound 1 showed prevention of Aβ-induced neurotoxicity and neuroprotective efficacy in Drosophila system. However, mechanism of action of compound 1 and its effect on the amyloid is not known. We therefore performed molecular docking and atomistic, explicit-solvent molecular dynamics simulations to investigate the process of Aβ interaction, inhibition, and destabilizing mechanism. Results showed different preferred binding sites of compound 1 and good affinity toward the target. Through the course of 35 ns molecular dynamics simulation, conformations_5 of compound 1 intercalates into the hydrophobic core near the salt bridge and showed major structural changes as compared to other conformations. Compound 1 showed interference with the salt bridge and thus reducing the inter strand hydrogen bound network. This minimizes the side chain interaction between the chains A-B leading to disorder in oligomer. Contact map analysis of amino acid residues between chains A and B also showed lesser interaction with adjacent amino acids in the presence of compound 1 (conformations_5). The study provides an insight into how compound 1 interferes and disorders the Aβ peptide. These findings will further help to design better inhibitors for aggregation of the amyloid oligomer. PMID:26208790

  4. Nicotinamide mononucleotide protects against β-amyloid oligomer-induced cognitive impairment and neuronal death.

    Wang, Xiaonan; Hu, Xuejun; Yang, Yang; Takata, Toshihiro; Sakurai, Takashi

    2016-07-15

    Amyloid-β (Aβ) oligomers are recognized as the primary neurotoxic agents in Alzheimer's disease (AD). Impaired brain energy metabolism and oxidative stress are implicated in cognitive decline in AD. Nicotinamide adenine dinucleotide (NAD(+)), a coenzyme involved in redox activities in the mitochondrial electron transport chain, has been identified as a key regulator of the lifespan-extending effects, and the activation of NAD(+) expression has been linked with a decrease in Aβ toxicity in AD. One of the key precursors of NAD(+) is nicotinamide mononucleotide (NMN), a product of the nicotinamide phosphoribosyltransferase reaction. To determine whether improving brain energy metabolism will forestall disease progress in AD, the impact of the NAD(+) precursor NMN on Aβ oligomer-induced neuronal death and cognitive impairment were studied in organotypic hippocampal slice cultures (OHCs) and in a rat model of AD. Treatment of intracerebroventricular Aβ oligomer infusion AD model rats with NMN (500mg/kg, intraperitoneally) sustained improvement in cognitive function as assessed by the Morris water maze. In OHCs, Aβ oligomer-treated culture media with NMN attenuated neuronal cell death. NMN treatment also significantly prevented the Aβ oligomer-induced inhibition of LTP. Furthermore, NMN restored levels of NAD(+) and ATP, eliminated accumulation of reactive oxygen species (ROS) in the Aβ oligomer-treated hippocampal slices. All these protective effects were reversed by 3-acetylpyridine, which generates inactive NAD(+). The present study indicates that NMN could restore cognition in AD model rats. The beneficial effect of NMN is produced by ameliorating neuron survival, improving energy metabolism and reducing ROS accumulation. These results suggest that NMN may become a promising therapeutic drug for AD. PMID:27130898

  5. 女贞果实及种子的化学成分%The chemical constituents from fruits and seeds of Ligustrum lucidum Ait.

    林文群; 陈忠; 李萍; 刘剑秋

    2002-01-01

    The chemical constituents from fruits and seeds of Ligustrum lucidum Ait. Were determined. The content of fatty oil in the seeds reached 14.70%. The main constituents of fatty acid were: oleic acid (44.37%), linoleic acid (40.378%), linolenic acid (0.867%), palmitic acid (4.525%), stearic acid (1.843%) etc, and the contents of unsaturated fatty acid reached 88.184%, the seed oil was of higher nutrient value. The contents of amino acids and mineral elements were relatively abundant. The content of total sugar of the fruits was rich also. And its fruits and seeds were of potential values in exploitation and utilization.

  6. Hazardous constituent source term. Revision 2

    1994-11-17

    The Department of Energy (DOE) has several facilities that either generate and/or store transuranic (TRU)-waste from weapons program research and production. Much of this waste also contains hazardous waste constituents as regulated under Subtitle C of the Resource Conservation and Recovery Act (RCRA). Toxicity characteristic metals in the waste principally include lead, occurring in leaded rubber gloves and shielding. Other RCRA metals may occur as contaminants in pyrochemical salt, soil, debris, and sludge and solidified liquids, as well as in equipment resulting from decontamination and decommissioning activities. Volatile organic compounds (VOCS) contaminate many waste forms as a residue adsorbed on surfaces or occur in sludge and solidified liquids. Due to the presence of these hazardous constituents, applicable disposal regulations include land disposal restrictions established by Hazardous and Solid Waste Amendments (HSWA). The DOE plans to dispose of TRU-mixed waste from the weapons program in the Waste Isolation Pilot Plant (WIPP) by demonstrating no-migration of hazardous constituents. This paper documents the current technical basis for methodologies proposed to develop a post-closure RCRA hazardous constituent source term. For the purposes of demonstrating no-migration, the hazardous constituent source term is defined as the quantities of hazardous constituents that are available for transport after repository closure. Development of the source term is only one of several activities that will be involved in the no-migration demonstration. The demonstration will also include uncertainty and sensitivity analyses of contaminant transport.

  7. Synthesis and incorporation of thienylene vinylene oligomers in main-chain copolymers

    Madrigal, L.G.; Elandaloussi, E.H.; Spangler, C.W.

    1998-07-01

    Poly [2,5-thienylene vinylene] (PTV) has been studied extensively over the past decade for both its metallic conductivity behavior upon chemical doping, as well as its interesting third order nonlinear optical properties. PTV oligomers have been synthesized by the group, as well as others, and the formation of polaron-like radical-cations or bipolaron-like dications by oxidative doping has been demonstrated. In this paper the authors describe a general synthetic approach to PTV oligomers functionalized for copolymer formation by step-growth reaction.

  8. Considerable Enhancement of Emission Yields of [Au(CN)2(-)] Oligomers in Aqueous Solutions by Coexisting Cations.

    Wakabayashi, Ryo; Maeba, Junichi; Nozaki, Koichi; Iwamura, Munetaka

    2016-08-01

    The photophysical properties of [Au(CN)2(-)] oligomers in aqueous solutions were investigated as functions of coexisting cations as well as the viscosity and temperature of solutions. A solution of [Au(CN)2(-)] in the concentration range of 0.03-0.2 mol/dm(3) exhibited emission peaks at 460-480 nm because of the presence of oligomers larger than trimers. Although the emission yields (ϕem) of K[Au(CN)2] solutions were wavelength regions were very short and independent of the viscosity of the solutions and coexisting cations (dimer, ∼25 ps; trimer, ∼2 ns). These results indicated that the deactivation of the excited-state [Au(CN)2(-)]n oligomers (n ≥ 4) was dominated by the dissociation of the oligomers to a shorter species (dimer or trimer). The hydrophobic interactions between tetraalkylammonium cations and CN ligands remarkably stabilized the larger oligomers and suppressed the dissociation of the excited-state oligomers, which enhanced the emission yield of the oligomers. This work provides a new method of "exciplex tuning" by changing the environment of excited-state [Au(CN)2(-)]n oligomers. PMID:27391559

  9. Enzymatic production of defined chitosan oligomers with a specific pattern of acetylation using a combination of chitin oligosaccharide deacetylases

    Hamer, Stefanie Nicole; Cord-Landwehr, Stefan; Biarnés, Xevi; Planas, Antoni; Waegeman, Hendrik; Moerschbacher, Bruno Maria; Kolkenbrock, Stephan

    2015-03-01

    Chitin and chitosan oligomers have diverse biological activities with potentially valuable applications in fields like medicine, cosmetics, or agriculture. These properties may depend not only on the degrees of polymerization and acetylation, but also on a specific pattern of acetylation (PA) that cannot be controlled when the oligomers are produced by chemical hydrolysis. To determine the influence of the PA on the biological activities, defined chitosan oligomers in sufficient amounts are needed. Chitosan oligomers with specific PA can be produced by enzymatic deacetylation of chitin oligomers, but the diversity is limited by the low number of chitin deacetylases available. We have produced specific chitosan oligomers which are deacetylated at the first two units starting from the non-reducing end by the combined use of two different chitin deacetylases, namely NodB from Rhizobium sp. GRH2 that deacetylates the first unit and COD from Vibrio cholerae that deacetylates the second unit starting from the non-reducing end. Both chitin deacetylases accept the product of each other resulting in production of chitosan oligomers with a novel and defined PA. When extended to further chitin deacetylases, this approach has the potential to yield a large range of novel chitosan oligomers with a fully defined architecture.

  10. A NEW APPROACH TO ELECTROACTIVE POLYMERS VIA WELL-DEFINED OLIGOMERS WITH FURTHER POLYMERIZABLE END-GROUPS

    Yen Wei; You-hai Yu; Wan-jin Zhang; Ce Wang; Xin-ru Jia; Susan A. Jansen

    2002-01-01

    Among the inherent drawbacks of conducting polymers are the limited processibility, uneven polydispersity in molecular weight and the existence of structure defects, which become the obstacles for many electronic, optical and biological applications that demand the materials to have well-defined structures and high chemical purity. To solve these problems, our research in the last decade or so has focused on the synthesis of electroactive oligomers of well-defined structures, controllable molecular weights, narrow or uniform polydispersity. We have developed a general strategy for the synthesis of such oligomers based on the theory of non-classical or reactivation chain polymerization. The aniline oligomers with minimum 4 nitrogen atoms and 3 phenylene rings exhibit similar characteristic redox behavior and electroactivity as polyaniline. Electronic conductivity of the oligomers of 7 or 8 aniline units approaches that of polyaniline. Solubility of the oligomers is much improved over that of conventional polyaniline. Various functional groups can be introduced into the oligomers either by proper selection of starting materials or by post-synthesis modifications via common organic reactions. The functionalized oligomers undergo further polymerizations to afford a variety of new electroactive materials, including polyamides, polyimides, polyureas, polyurethanes, polyacrylamides and epoxy polymers. Numerous potential applications, particularly as anticorrosion materials, are discussed for the oligomers and their polymeric derivatives.

  11. Chemical constituents from Melaleuca alternifolia (Myrtaceae); Constituintes quimicos de Melaleuca alternifolia (Myrtaceae)

    Vieira, Tatiana R.; Barbosa, Luiz C.A.; Maltha, Celia R.A. [Vicosa Univ., MG (Brazil). Dept. de Quimica]. E-mail: lcab@ufv.br; Paula, Vanderlucia F. [Universidade Estadual do Sudoeste da Bahia, Jequie, BA (Brazil). Dept. de Quimica e Exatas; Nascimento, Evandro A. [Uberlandia Univ., MG (Brazil). Inst. de Quimica

    2004-08-01

    The first chemical study of non-volatile constituents from the bark and stem of Melaleuca alternifolia (Myrtaceae) led to the isolation and identification of 3,3'-O-dimethylellagic acid (1) and five pentacyclic triterpenes: 2{alpha},3{beta},23-trihydroxyolean-12-en-28-oic acid (arjunolic acid, 2), 3{beta}-hydroxylup-20(29)-en-27,28-dioic acid (melaleucic acid, 3), betulinic acid (4), betuline (5), 3{beta}-O-acetylurs-12-en-28-oic acid (6), a mixture of fatty acids and esters, and several hydrocarbons. For 2{alpha},3{beta},23-trihydroxyolean-12-en-28-oic acid (2) and 3{beta}-O-acetylurs-12-en-28-oic acid (6) a first detailed assignment of {sup 1}H NMR is presented. (author)

  12. Constituintes químicos de Melaleuca alternifolia (Myrtaceae Chemical constituents from Melaleuca alternifolia (Myrtaceae

    Tatiana R. Vieira

    2004-08-01

    Full Text Available The first chemical study of non-volatile constituents from the bark and stem of Melaleuca alternifolia (Myrtaceae led to the isolation and identification of 3,3'-O-dimethylellagic acid (1 and five pentacyclic triterpenes: 2alpha,3beta,23-trihydroxyolean-12-en-28-oic acid (arjunolic acid, 2, 3beta-hydroxylup-20(29-en-27,28-dioic acid (melaleucic acid, 3, betulinic acid (4, betuline (5, 3beta-O-acetylurs-12-en-28-oic acid (6, a mixture of fatty acids and esters, and several hydrocarbons. For 2alpha,3beta,23-trihydroxyolean-12-en-28-oic acid (2 and 3beta-O-acetylurs-12-en-28-oic acid (6 a first detailed assignment of ¹H NMR is presented.

  13. Crystallization and preliminary crystallographic study of oligomers of the haemolytic lectin CEL-III from the sea cucumber Cucumaria echinata.

    Unno, Hideaki; Hisamatsu, Keigo; Nagao, Tomonao; Tateya, Yuki; Matsumoto, Naoki; Goda, Shuichiro; Hatakeyama, Tomomitsu

    2013-04-01

    CEL-III is a Ca(2+)-dependent haemolytic lectin isolated from the marine invertebrate Cucumaria echinata. This lectin binds to Gal/GalNAc-containing carbohydrate chains on the cell surface and, after conformational changes, oligomerizes to form ion-permeable pores in cell membranes. CEL-III also forms soluble oligomers similar to those formed in cell membranes upon binding of specific carbohydrates in high-pH and high-salt solutions. These soluble and membrane CEL-III oligomers were crystallized and X-ray diffraction data were collected. Crystals of soluble oligomers and membrane oligomers diffracted X-rays to 3.3 and 4.2 Å resolution, respectively, using synchrotron radiation and the former was found to belong to space group C2. Self-rotation functional analysis of the soluble oligomer crystal suggested that it might be composed of heptameric CEL-III. PMID:23545649

  14. Morphology and mechanical properties of radiation-polymerized urethane-acrylates. I. Pure oligomers. [Electron beams and gamma radiation of acrylo-urethane oligomers

    Wadhwa, L.H.; Walsh, W.K.

    1982-02-01

    The morphology of electron beam cured polyacrylo-urethane films based on polyethylene adipate and toluene diisocyanate was characterized to explain their mechanical properties. The polyacrylo-urethane films have a one-phase morphology in which the hard urethane segments and the soft polyester segments are homogeneously mixed. The films obtained from 1000-molecular-weight oligomer are hard and somewhat brittle due to their one-phase morphology in which hard glassy segments play a dominant role. The films obtained from 4600- and 6000-molecular-weight oligomers are soft and tough, once again due to their one-phase morphology in which soft rubbery segments are more effective. The original crystalline structure of 6000-molecular-weight oligomer is retained in the precrystallized ..gamma..-irradiated film, but electron-beam-irradiated films showed partial melting of the crystallites due to the heat of polymerization. The solid state polymerized films have a lower elongation, a higher modulus, and a higher breaking strength due to their crystallinity.

  15. Correlated Conformational Motions of the KH Domains of Far Upstream Element Binding Protein Complexed with Single-Stranded DNA Oligomers.

    Chakraborty, Kaushik; Bandyopadhyay, Sanjoy

    2015-08-27

    Single-stranded DNA binding (SSB) proteins bind with single-stranded DNA (ss-DNA) segments that are generated as intermediates during DNA metabolic processes. The primary function of an SSB protein is to protect the ss-DNA from being degraded so that other enzymes can effectively act on it. We have performed atomistic molecular dynamics simulations of the two DNA binding K homology (KH) domains (KH3 and KH4) of the far upstream element (FUSE) binding protein (FBP) complexed with two ss-DNA oligomers in aqueous solutions. Attempts have been made to study the effects of complexation on the internal motions of the protein domains and the correlated dynamics of the amino acid residue side chains. In agreement with experiments, KH3 domain has been found to be relatively more flexible in the complexed state. The calculations reveal increased long-range anticorrelated motions among several amino acid residues in the complexed forms. Compared to the KH4 domain, noticeable increase in N-H dipole ordering on complexation has been observed for the KH3 domain. Importantly, it is demonstrated that the effects of the DNA strands on the side chain orientations of the arginine and lysine residues and their ordering and dynamics play critical roles in forming the complexes and their structural stability. PMID:25830509

  16. Chemical constituents of Panax ginseng exposed to. gamma. irradiation

    Kwon, Joongho; Belanger, J.M.R.; Sigouin, M.; Lanthier, J.; Willemot, C.; Pare, J.R.J. (Agriculture Canada, Saint-Hyacinthe, Quebec (Canada))

    1990-03-01

    Chemical constituents were monitored to assess the biochemical and nutritional safety of Panax ginseng powders that were irradiated at doses of 1-10 kGy. Quantitative analysis has shown that the main effective components - saponins - are not altered by {sup 60}Co {gamma} irradiation. Ginsenoside-Rg{sub 1} was not affected by the treatment. Negligible changes were observed in the free carbohydrate contents. Doses of more than 5 kGy caused significant decreases in sulfur-containing amino acids and in tyrosine. At doses of 10 kGy, free amino acids, such as proline and lysine, showed an appreciable increase. The composition in minerals was not altered irrespective of the applied doses.

  17. Tyrosinase Inhibitory Chemical Constituents from Cleyera japonica Thunberg Branches

    Jung Eun Kim

    2014-05-01

    Full Text Available Bioassay-guided investigation of the branches of Cleyera japonica led to the isolation of four phenolic constituents: 3,3’-di-O-methylellagic acid (1, 3,3’-di-O-methylellagic acid 4’-O-β-D-xylofuranoside (2, 3,5,7-trihydroxychromone 3-O-α-L-arabinofuranoside (3 and aviculin (4. Their structures were elucidated on the basis of spectral studies, as well as by comparison with literature data. Tyrosinase inhibition activities were carried out for the isolated compounds using arbutin as a positive control. Among them, compound 2 was identified as a potent tyrosinase inhibitor. It inhibited mushroom tyrosinase with an IC50 value of 0.078 mM, which is about three times more active than arbutin (IC50 =0.25 mM. All of the compounds 1-4 were isolated for the first time from this plant.

  18. Rubus Fruticosus L.: Constituents, Biological Activities and Health Related Uses

    Muhammad Zia-Ul-Haq

    2014-07-01

    Full Text Available Rubus fruticosus L. is a shrub famous for its fruit called blackberry fruit or more commonly blackberry. The fruit has medicinal, cosmetic and nutritive value. It is a concentrated source of valuable nutrients, as well as bioactive constituents of therapeutic interest highlighting its importance as a functional food. Besides use as a fresh fruit, it is also used as ingredient in cooked dishes, salads and bakery products like jams, snacks, desserts, and fruit preserves. R. fruticosus contains vitamins, steroids and lipids in seed oil and minerals, flavonoids, glycosides, terpenes, acids and tannins in aerial parts that possess diverse pharmacological activities such as antioxidant, anti-carcinogenic, anti-inflammatory, antimicrobial anti-diabetic, anti-diarrheal, and antiviral. Various agrogeoclimatological factors like cultivar, environmental conditions of the area, agronomic practices employed, harvest time, post-harvest storage and processing techniques all influence the nutritional composition of blackberry fruit. This review focuses on the nutrients and chemical constituents as well as medicinal properties of different parts of R. fruticosus. Various cultivars and their physicochemical characteristics, polyphenolic content and ascorbic acid content are also discussed. The information in the present work will serve as baseline data and may lead to new biomedical applications of R. fruticosus as functional food.

  19. Crataegus pinnatifida: Chemical Constituents, Pharmacology, and Potential Applications

    Jiaqi Wu

    2014-01-01

    Full Text Available Crataegus pinnatifida (Hawthorn is widely distributed in China and has a long history of use as a traditional medicine. The fruit of C. pinnatifida has been used for the treatment of cardiodynia, hernia, dyspepsia, postpartum blood stasis, and hemafecia and thus increasing interest in this plant has emerged in recent years. Between 1966 and 2013, numerous articles have been published on the chemical constituents, pharmacology or pharmacologic effects and toxicology of C. pinnatifida. To review the pharmacologic advances and to discuss the potential perspective for future investigation, we have summarized the main literature findings of these publications. So far, over 150 compounds including flavonoids, triterpenoids, steroids, monoterpenoids, sesquiterpenoids, lignans, hydroxycinnamic acids, organic acids and nitrogen-containing compounds have been isolated and identified from C. pinnatifida. It has been found that these constituents and extracts of C. pinnatifida have broad pharmacological effects with low toxicity on, for example, the cardiovascular, digestive, and endocrine systems, and pathogenic microorganisms, supporting the view that C. pinnatifida has favorable therapeutic effects. Thus, although C. pinnatifida has already been widely used as pharmacological therapy, due to its various active compounds, further research is warranted to develop new drugs.

  20. Crataegus pinnatifida: chemical constituents, pharmacology, and potential applications.

    Wu, Jiaqi; Peng, Wei; Qin, Rongxin; Zhou, Hong

    2014-01-01

    Crataegus pinnatifida (Hawthorn) is widely distributed in China and has a long history of use as a traditional medicine. The fruit of C. pinnatifida has been used for the treatment of cardiodynia, hernia, dyspepsia, postpartum blood stasis, and hemafecia and thus increasing interest in this plant has emerged in recent years. Between 1966 and 2013, numerous articles have been published on the chemical constituents, pharmacology or pharmacologic effects and toxicology of C. pinnatifida. To review the pharmacologic advances and to discuss the potential perspective for future investigation, we have summarized the main literature findings of these publications. So far, over 150 compounds including flavonoids, triterpenoids, steroids, monoterpenoids, sesquiterpenoids, lignans, hydroxycinnamic acids, organic acids and nitrogen-containing compounds have been isolated and identified from C. pinnatifida. It has been found that these constituents and extracts of C. pinnatifida have broad pharmacological effects with low toxicity on, for example, the cardiovascular, digestive, and endocrine systems, and pathogenic microorganisms, supporting the view that C. pinnatifida has favorable therapeutic effects. Thus, although C. pinnatifida has already been widely used as pharmacological therapy, due to its various active compounds, further research is warranted to develop new drugs. PMID:24487567

  1. Cytotoxic helix-rich oligomer formation by melittin and pancreatic polypeptide.

    Pradeep K Singh

    Full Text Available Conversion of amyloid fibrils by many peptides/proteins involves cytotoxic helix-rich oligomers. However, their toxicity and biophysical studies remain largely unknown due to their highly dynamic nature. To address this, we chose two helical peptides (melittin, Mel and pancreatic polypeptide, PP and studied their aggregation and toxicity. Mel converted its random coil structure to oligomeric helical structure upon binding to heparin; however, PP remained as helix after oligomerization. Interestingly, similar to Parkinson's associated α-synuclein (AS oligomers, Mel and PP also showed tinctorial properties, higher hydrophobic surface exposure, cellular toxicity and membrane pore formation after oligomerization in the presence of heparin. We suggest that helix-rich oligomers with exposed hydrophobic surface are highly cytotoxic to cells irrespective of their disease association. Moreover as Mel and PP (in the presence of heparin instantly self-assemble into stable helix-rich amyloidogenic oligomers; they could be represented as models for understanding the biophysical and cytotoxic properties of helix-rich intermediates in detail.

  2. High-resolution NMR characterization of low abundance oligomers of amyloid-β without purification.

    Kotler, Samuel A; Brender, Jeffrey R; Vivekanandan, Subramanian; Suzuki, Yuta; Yamamoto, Kazutoshi; Monette, Martine; Krishnamoorthy, Janarthanan; Walsh, Patrick; Cauble, Meagan; Holl, Mark M Banaszak; Marsh, E Neil G; Ramamoorthy, Ayyalusamy

    2015-01-01

    Alzheimer's disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling (1)H-(1)H NMR experiments to overcome many of these limitations. Using (1)H-(1)H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time (1)H-(1)H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5-15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils. PMID:26138908

  3. Hybrid Conjugated Organic Oligomers Consisting of Oligodiacetylene and Thiophene Units: Synthesis and Optical Properties

    Pilzak, G.S.; Gruijthuijsen, van K.; Doorn, van R.H.; Lagen, van B.; Sudhölter, E.J.R.; Zuilhof, H.

    2009-01-01

    Novel and highly soluble hybrid conjugated organic oligomers consisting of oligodiacetylene and thiophene units have been synthesized in high purity through iterative and divergent approaches based on a sequence of Sonogashira reactions. The series of thiophene-containing oligodiacetylenes (ThODAs)

  4. Structure–property relationships of synthetic organophosphorus flame retardant oligomers by thermal analysis

    Highlights: • Oligomers with different chemical components in molecular chains were synthesized. • FP-3 containing three IFR components possessed high thermal stability. • FP-3 possessed lowest flammability. • FP-3 exhibited a synergistic interaction between gas and condensed phase. - Abstract: A series of flame retardant oligomers with different chemical components in molecular chains, designated as FP-1, FP-2 and FP-3, respectively, were successfully synthesized using solution polycondensation and well characterized. The thermal properties and flammability of these oligomers were investigated by thermogravimetric analysis (TGA) and microscale combustion calorimeter (MCC). The results demonstrated that FP-3 had the lowest flammability in terms of the lowest maximum mass loss rate, and FP-1 possessed the highest thermal stability and char yield, due to its higher stable hexatomic ring structure of piperazine compared with the linear alkane chain structure of neopentyl glycol. The gases evolved during decomposition were analyzed using Fourier transform infrared coupled with the thermogravimetric analyzer (TG–IR) technique. The char residues of the flame retardant oligomers were investigated by scanning electron microscopy (SEM) and Raman spectroscopy. The results demonstrated that FP-3 exhibited a synergistic interaction between the gas phase and condensation phase, increasing its flame retardancy

  5. Ultrafast Photoinduced Electron Transfer in a π-Conjugated Oligomer/Porphyrin Complex

    Aly, Shawkat Mohammede

    2014-10-02

    Controlling charge transfer (CT), charge separation (CS), and charge recombination (CR) at the donor-acceptor interface is extremely important to optimize the conversion efficiency in solar cell devices. In general, ultrafast CT and slow CR are desirable for optimal device performance. In this Letter, the ultrafast excited-state CT between platinum oligomer (DPP-Pt(acac)) as a new electron donor and porphyrin as an electron acceptor is monitored for the first time using femtosecond (fs) transient absorption (TA) spectroscopy with broad-band capability and 120 fs temporal resolution. Turning the CT on/off has been shown to be possible either by switching from an organometallic oligomer to a metal-free oligomer or by controlling the charge density on the nitrogen atom of the porphyrin meso unit. Our time-resolved data show that the CT and CS between DPP-Pt(acac) and cationic porphyrin are ultrafast (approximately 1.5 ps), and the CR is slow (ns time scale), as inferred from the formation and the decay of the cationic and anionic species. We also found that the metallic center in the DPP-Pt(acac) oligomer and the positive charge on the porphyrin are the keys to switching on/off the ultrafast CT process.

  6. Diverse metastable structures formed by small oligomers of α-synuclein probed by force spectroscopy.

    Krishna Neupane

    Full Text Available Oligomeric aggregates are widely suspected as toxic agents in diseases caused by protein aggregation, yet they remain poorly characterized, partly because they are challenging to isolate from a heterogeneous mixture of species. We developed an assay for characterizing structure, stability, and kinetics of individual oligomers at high resolution and sensitivity using single-molecule force spectroscopy, and applied it to observe the formation of transient structured aggregates within single oligomers of α-synuclein, an intrinsically-disordered protein linked to Parkinson's disease. Measurements of the molecular extension as the proteins unfolded under tension in optical tweezers revealed that even small oligomers could form numerous metastable structures, with a surprisingly broad range of sizes. Comparing the structures formed in monomers, dimers and tetramers, we found that the average mechanical stability increased with oligomer size. Most structures formed within a minute, with size-dependent rates. These results provide a new window onto the complex α-synuclein aggregation landscape, characterizing the microscopic structural heterogeneity and kinetics of different pathways.

  7. Organization in sol-gel polymerization of methacrylate co-oligomers containing trimethoxysilylpropyl methacrylate

    Vraštil, J.; Matějka, Libor; Špaček, V.; Večeřa, M.; Prokůpek, L.

    2005-01-01

    Roč. 46, č. 25 (2005), s. 11232-11240. ISSN 0032-3861 Institutional research plan: CEZ:AV0Z40500505 Keywords : organic-inorganic hybrid * sol-gel process * oligomers Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.849, year: 2005

  8. Development of new fusion proteins for visualizing amyloid-β oligomers in vivo.

    Ochiishi, Tomoyo; Doi, Motomichi; Yamasaki, Kazuhiko; Hirose, Keiko; Kitamura, Akira; Urabe, Takao; Hattori, Nobutaka; Kinjo, Masataka; Ebihara, Tatsuhiko; Shimura, Hideki

    2016-01-01

    The intracellular accumulation of amyloid-β (Aβ) oligomers critically contributes to disease progression in Alzheimer's disease (AD) and can be the potential target of AD therapy. Direct observation of molecular dynamics of Aβ oligomers in vivo is key for drug discovery research, however, it has been challenging because Aβ aggregation inhibits the fluorescence from fusion proteins. Here, we developed Aβ1-42-GFP fusion proteins that are oligomerized and visualize their dynamics inside cells even when aggregated. We examined the aggregation states of Aβ-GFP fusion proteins using several methods and confirmed that they did not assemble into fibrils, but instead formed oligomers in vitro and in live cells. By arranging the length of the liker between Aβ and GFP, we generated two fusion proteins with "a long-linker" and "a short-linker", and revealed that the aggregation property of fusion proteins can be evaluated by measuring fluorescence intensities using rat primary culture neurons transfected with Aβ-GFP plasmids and Aβ-GFP transgenic C. elegans. We found that Aβ-GFP fusion proteins induced cell death in COS7 cells. These results suggested that novel Aβ-GFP fusion proteins could be utilized for studying the physiological functions of Aβ oligomers in living cells and animals, and for drug screening by analyzing Aβ toxicity. PMID:26982553

  9. Detection of aniline oligomers on polyaniline-gold interface using resonance Raman scattering

    Trchová, Miroslava; Morávková, Zuzana; Dybal, Jiří; Stejskal, Jaroslav

    2014-01-01

    Roč. 6, č. 2 (2014), s. 942-950. ISSN 1944-8244 R&D Projects: GA ČR GAP205/12/0911; GA ČR(CZ) GA13-00270S Institutional support: RVO:61389013 Keywords : polyaniline * aniline oligomers * Raman spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 6.723, year: 2014

  10. Solid state properties of oligomers containing dithienothiophene or fluorene residues suitable for field effect transistor devices

    Porzio, William [Istituto per lo Studio delle Macromolecole del C.N.R. via E. Bassini 15, 20133 Milan (Italy)]. E-mail: w.porzio@ismac.cnr.it; Destri, Silvia [Istituto per lo Studio delle Macromolecole del C.N.R. via E. Bassini 15, 20133 Milan (Italy); Giovanella, Umberto [Istituto per lo Studio delle Macromolecole del C.N.R. via E. Bassini 15, 20133 Milan (Italy); Pasini, Mariacecilia; Marin, Luminita [Istituto per lo Studio delle Macromolecole del C.N.R. via E. Bassini 15, 20133 Milan (Italy); Institute of Macromolecular Chemistry 41A Grigore Ghica Voda Alley, 708487 Iasi (Romania); Iosip, Mariana Dana [Istituto per lo Studio delle Macromolecole del C.N.R. via E. Bassini 15, 20133 Milan (Italy); Institute of Macromolecular Chemistry 41A Grigore Ghica Voda Alley, 708487 Iasi (Romania); Campione, Marcello [Dipartimento di Scienza dei Materiali, Universita di Milano Bicocca, via E. Cozzi 53, Milan (Italy)

    2007-06-25

    A series of three thiophene based oligomers has been extensively characterized. The chemical design has been addressed to obtain ionization potential (IP) and electronic affinity (EA) values matching the work function of commonly used electrode materials. Such IP and EA values were tested by cyclovoltammetry. In order to tune electron-donation and drawing strength the sequence of the molecule subunits in the oligomer has been varied. The thermal properties with particular reference to their stability during preparation and operation were checked by using differential scanning calorimetry, polarised light microscopy and thermogravimetric analysis techniques. Prototypes of thin film field effect transistor, based on this series of oligomers have been electrically and structurally characterized. The long axes of the molecules are oriented nearly perpendicular to the gate insulator, in agreement with both highly sensitive X-ray diffraction and atomic force microscopy. From powder diffraction data the structure of oligomer I was solved. A general relation is envisaged between charge mobility and packing closeness in the series. For the most promising molecule a study of mobility/temperature behaviour was performed yielding interesting results.

  11. Towards directional assembly of hierarchical structures: aniline oligomers as the model precursors

    Zhao, Y.; Stejskal, Jaroslav; Wang, J.

    2013-01-01

    Roč. 5, č. 7 (2013), s. 2620-2626. ISSN 2040-3364 R&D Projects: GA ČR GAP205/12/0911 Institutional support: RVO:61389013 Keywords : aniline oligomers * hierarchical nanostructures * microflowers Subject RIV: CD - Macromolecular Chemistry Impact factor: 6.739, year: 2013

  12. A cytotoxic amyloid oligomer self-triggered and NIR- enhanced amyloidosis therapeutic system

    Can Xu[1,2; Peng Shi[1,2; Meng Li[1,2; Jinsong Ren[1; xiaogang Qu[1

    2015-01-01

    We report a new strategy for improving the efficiency of non-specific amyloidosis therapeutic drugs by coating amyloid-responsive lipid bilayers. The approach had drawn inspiration from amyloid oligomer-mediated cell membrane disruption in the pathogenesis of amyloidosis. A graphene-mesoporous silica hybrid (GMS)-supported lipid bilayer (GMS-Lip) system was used as a drug carrier, Drugs were well confined inside the nanocarrier until encountering amyloid oligomers, which could pierce the lipid bilayer coat and cause drug release. To ensure release efficiency, use of a near-infrared (NIR) laser was also introduced to facilitate drug release, taking advantage of the photothermal effect of GMS and thermal sensitivity of lipid bilayers. To facilitate tracking, fluorescent dyes were co-loaded with drugs within GMS-Lip and the NIR laser was used once the oligomer-triggered release had been signaled. Because of the spatially and temporally controllable property of light, the NIR-assisted release could be easily and selectively activated locally by tracking the fluorescence signal. Our design is based on arnyloidosis pathogenesis, the cytotoxic amyloid oligomer self-triggered release via cell membrane disruption, for the controlled release of drug molecules. The results may shed light on the development of pathogenesis- inspired drug delivery systems,

  13. Designing thiophene-based azomethine oligomers with tailored properties: Self-assembly and charge carrier mobility

    Kiriy, N.; Bocharova, V.; Kiriy, A.;

    2004-01-01

    quaterthiophene, considerably improves the self-assembly properties without suppression of solubility. Self-assembly of azomethine oligomers with (QT-amide) and without amide moieties (QT-aniline) were monitored by UV-vis, XRD, and AFM. Although no changes in the UV-vis spectrum of QT-aniline is observed upon...

  14. Tracking chromosomal positions of oligomers - a case study with Illumina's BovineSNP50 beadchip

    Brockmann Gudrun A

    2010-02-01

    Full Text Available Abstract Background High density genotyping arrays have become established as a valuable research tool in human genetics. Currently, more than 300 genome wide association studies were published for human reporting about 1,000 SNPs that are associated with a phenotype. Also in animal sciences high density genotyping arrays are harnessed to analyse genetic variation. To exploit the full potential of this technology single nucleotide polymorphisms (SNPs on the chips should be well characterized and their chromosomal position should be precisely known. This, however, is a challenge if the genome sequence is still subject to changes. Results We have developed a mapping strategy and a suite of software scripts to update the chromosomal positions of oligomer sequences used for SNP genotyping on high density arrays. We describe the mapping procedure in detail so that scientists with moderate bioinformatics skills can reproduce it. We furthermore present a case study in which we re-mapped 54,001 oligomer sequences from Ilumina's BovineSNP50 beadchip to the bovine genome sequence. We found in 992 cases substantial discrepancies between the manufacturer's annotations and our results. The software scripts in the Perl and R programming languages are provided as supplements. Conclusions The positions of oligomer sequences in the genome are volatile even within one build of the genome. To facilitate the analysis of data from a GWAS or from an expression study, especially with species whose genome assembly is still unstable, it is recommended to update the oligomer positions before data analysis.

  15. Structure–property relationships of synthetic organophosphorus flame retardant oligomers by thermal analysis

    Bai, Zhiman [State Key Lab of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren’ai Road Suzhou, Jiangsu 215123 (China); Wang, Xin; Tang, Gang; Song, Lei [State Key Lab of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Lab of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren’ai Road Suzhou, Jiangsu 215123 (China); Yuen, Richard K.K., E-mail: Richard.Yuen@cityu.edu.hk [USTC-CityU Joint Advanced Research Centre, Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren’ai Road Suzhou, Jiangsu 215123 (China); Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue Kowloon (Hong Kong)

    2013-08-10

    Highlights: • Oligomers with different chemical components in molecular chains were synthesized. • FP-3 containing three IFR components possessed high thermal stability. • FP-3 possessed lowest flammability. • FP-3 exhibited a synergistic interaction between gas and condensed phase. - Abstract: A series of flame retardant oligomers with different chemical components in molecular chains, designated as FP-1, FP-2 and FP-3, respectively, were successfully synthesized using solution polycondensation and well characterized. The thermal properties and flammability of these oligomers were investigated by thermogravimetric analysis (TGA) and microscale combustion calorimeter (MCC). The results demonstrated that FP-3 had the lowest flammability in terms of the lowest maximum mass loss rate, and FP-1 possessed the highest thermal stability and char yield, due to its higher stable hexatomic ring structure of piperazine compared with the linear alkane chain structure of neopentyl glycol. The gases evolved during decomposition were analyzed using Fourier transform infrared coupled with the thermogravimetric analyzer (TG–IR) technique. The char residues of the flame retardant oligomers were investigated by scanning electron microscopy (SEM) and Raman spectroscopy. The results demonstrated that FP-3 exhibited a synergistic interaction between the gas phase and condensation phase, increasing its flame retardancy.

  16. High-capacity conductive nanocellulose paper sheets for electrochemically controlled extraction of DNA oligomers.

    Aamir Razaq

    Full Text Available Highly porous polypyrrole (PPy-nanocellulose paper sheets have been evaluated as inexpensive and disposable electrochemically controlled three-dimensional solid phase extraction materials. The composites, which had a total anion exchange capacity of about 1.1 mol kg(-1, were used for extraction and subsequent release of negatively charged fluorophore tagged DNA oligomers via galvanostatic oxidation and reduction of a 30-50 nm conformal PPy layer on the cellulose substrate. The ion exchange capacity, which was, at least, two orders of magnitude higher than those previously reached in electrochemically controlled extraction, originated from the high surface area (i.e. 80 m(2 g(-1 of the porous composites and the thin PPy layer which ensured excellent access to the ion exchange material. This enabled the extractions to be carried out faster and with better control of the PPy charge than with previously employed approaches. Experiments in equimolar mixtures of (dT(6, (dT(20, and (dT(40 DNA oligomers showed that all oligomers could be extracted, and that the smallest oligomer was preferentially released with an efficiency of up to 40% during the reduction of the PPy layer. These results indicate that the present material is very promising for the development of inexpensive and efficient electrochemically controlled ion-exchange membranes for batch-wise extraction of biomolecules.

  17. Development of new fusion proteins for visualizing amyloid-β oligomers in vivo

    Ochiishi, Tomoyo; Doi, Motomichi; Yamasaki, Kazuhiko; Hirose, Keiko; Kitamura, Akira; Urabe, Takao; Hattori, Nobutaka; Kinjo, Masataka; Ebihara, Tatsuhiko; Shimura, Hideki

    2016-01-01

    The intracellular accumulation of amyloid-β (Aβ) oligomers critically contributes to disease progression in Alzheimer’s disease (AD) and can be the potential target of AD therapy. Direct observation of molecular dynamics of Aβ oligomers in vivo is key for drug discovery research, however, it has been challenging because Aβ aggregation inhibits the fluorescence from fusion proteins. Here, we developed Aβ1-42-GFP fusion proteins that are oligomerized and visualize their dynamics inside cells even when aggregated. We examined the aggregation states of Aβ-GFP fusion proteins using several methods and confirmed that they did not assemble into fibrils, but instead formed oligomers in vitro and in live cells. By arranging the length of the liker between Aβ and GFP, we generated two fusion proteins with “a long-linker” and “a short-linker”, and revealed that the aggregation property of fusion proteins can be evaluated by measuring fluorescence intensities using rat primary culture neurons transfected with Aβ-GFP plasmids and Aβ-GFP transgenic C. elegans. We found that Aβ-GFP fusion proteins induced cell death in COS7 cells. These results suggested that novel Aβ-GFP fusion proteins could be utilized for studying the physiological functions of Aβ oligomers in living cells and animals, and for drug screening by analyzing Aβ toxicity. PMID:26982553

  18. Cholesterol facilitates interactions between α-synuclein oligomers and charge-neutral membranes

    van Maarschalkerweerd, Andreas; Vetri, Valeria; Vestergaard, Bente

    2015-01-01

    Oligomeric species formed during α-synuclein fibrillation are suggested to be membrane-disrupting agents, and have been associated with cytotoxicity in Parkinson's disease. The majority of studies, however, have revealed that the effect of α-synuclein oligomers is only noticeable on systems compo...

  19. NMR investigation of aniline oligomers produced in the oxidation of aniline in alkaline medium

    Kříž, Jaroslav; Konyushenko, Elena; Trchová, Miroslava; Stejskal, Jaroslav

    2011-01-01

    Roč. 60, č. 9 (2011), s. 1296-1302. ISSN 0959-8103 R&D Projects: GA ČR GA203/08/0686; GA AV ČR IAA400500905 Institutional research plan: CEZ:AV0Z40500505 Keywords : anilin e oligomers * polyaniline * anilin e oxidation Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.902, year: 2011

  20. UV curable lens production using molecular weight controlled PEEK based acrylic oligomer (Ac-PEEK).

    İnan, Tulay Y; Yıldız, Emel; Karaca, Birsen; Dogan, Hacer; Vatansever, Alican; Nalbant, Muhammed; Eken, Koray

    2014-08-01

    We produced UV curable lenses with properties blocking short wave UV light. In the UV-curable formulations, we used an oligomer (Ac-PEEK) with another urethan oligomer (Mw = 2000). Radically active, molecular weight controlled Ac-PEEK was obtained by reacting 2-hydroxyl ethyl methacrylate with molecular- weight- controlled and isocyanate terminated PEEK (Mn = 4500). We characterized all synthesized monomer, oligomer and optical materials with UV/Vis spectrophotometer with interferogram, elemental analyser, mass spectrophotometer, proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermal gravimetric analyzer, differential scanning calorimeter, scanning electron microscopy and gas chromatography. Results suggested that newly synthesized oligomer with the structure of PEEK absorbs short wave UV-light. Ageing tests [ISO 11979-5, Ophthalmic implants-intraocular lenses (IOL)-Part 5: Biocompatibility] performed on the IOL materials were successful. High contact angle of the obtained lenses suggests that all lenses were hydrophobic and SEM results revealed that lenses are morphologically homogeneous. Based on all positive properties just mentioned, we safely conclude that the lenses produced in this study are very promising for IOL production. PMID:24796625

  1. Carbonization of aniline oligomers to electrically polarizable particles and their use in electrorheology

    Plachý, T.; Sedlačík, M.; Pavlínek, V.; Trchová, Miroslava; Morávková, Zuzana; Stejskal, Jaroslav

    2014-01-01

    Roč. 256, 15 November (2014), s. 398-406. ISSN 1385-8947 R&D Projects: GA ČR GAP205/12/0911; GA ČR(CZ) GA13-08944S Institutional support: RVO:61389013 Keywords : anilin e * anilin e oligomers * carbonization Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.321, year: 2014

  2. Rapid Multistep Synthesis of a Bioactive Peptidomimetic Oligomer for the Undergraduate Laboratory

    Utku, Yeliz; Rohatgi, Abhinav; Yoo, Barney; Kirshenbaum, Kent; Zuckermann, Ronald N.; Pohl, Nicola L.

    2010-01-01

    Peptidomimetic compounds are increasingly important in drug-discovery applications. We introduce the synthesis of an N-substituted glycine oligomer, a bioactive "peptoid" trimer. The six-step protocol is conducted on solid-phase resin, enabling the synthesis to be performed by undergraduate organic chemistry students. This synthesis lab was…

  3. Folic acid-polydopamine nanofibers show enhanced ordered-stacking via π-π interactions.

    Fan, Hailong; Yu, Xiang; Liu, Yang; Shi, Zujin; Liu, Huihui; Nie, Zongxiu; Wu, Decheng; Jin, Zhaoxia

    2015-06-21

    Recent research has indicated that polydopamine and synthetic eumelanins are optoelectronic biomaterials in which one-dimensional aggregates composed of ordered-stacking oligomers have been proposed as unique organic semiconductors. However, improving the ordered-stacking of oligomers in polydopamine nanostructures is a big challenge. Herein, we first demonstrate how folic acid molecules influence the morphology and nanostructure of polydopamine via tuning the π-π interactions of oligomers. MALDI-TOF mass spectrometry reveals that porphyrin-like tetramers are characteristic of folic acid-polydopamine (FA-PDA) nanofibers. X-ray diffraction combined with simulation studies indicate that these oligomers favour aggregation into graphite-like ordered nanostructures via strong π-π interactions. High-resolution TEM characterization of carbonized FA-PDA hybrids show that in FA-PDA nanofibers the size of the graphite-like domains is over 100 nm. The addition of folic acid in polydopamine enhances the ordered stacking of oligomers in its nanostructure. Our study steps forward to discover the mystery of the structure-property relationship of FA-PDA hybrids. It paves a way to optimize the properties of PDA through the design and selection of oligomer structures. PMID:25959650

  4. Gluonic Structure of the Constituent Quark

    Kochelev, Nikolai; Zhang, Baiyang; Zhang, Pengming

    2015-01-01

    Based on both the constituent quark picture and the instanton model for QCD vacuum, we calculate the unpolarized and polarized gluon distributions in the constituent quark and in the nucleon. Our approach consists of the two main steps. At the first step, we calculate the gluon distributions inside the constituent quark generated by the perturbative quark-gluon interaction, the non-perturbative quark-gluon interaction, and the non-perturbative quark-gluon-pion anomalous chromomagnetic interaction. The non-perturbative interactions are related to the existence of the instantons, strong topological fluctuations of gluon fields, in the QCD vacuum. At the second step, the convolution model is applied to derive the gluon distributions in the nucleon. A very important role of the pion field in producing the unpolarized and the polarized gluon distributions in the hadrons is discovered. We discuss a possible solution of the proton spin problem.

  5. Gluonic structure of the constituent quark

    Kochelev, Nikolai; Lee, Hee-Jung; Zhang, Baiyang; Zhang, Pengming

    2016-06-01

    Based on both the constituent quark picture and the instanton model for QCD vacuum, we calculate the unpolarized and polarized gluon distributions in the constituent quark and in the nucleon. Our approach consists of the two main steps. At the first step, we calculate the gluon distributions inside the constituent quark generated by the perturbative quark-gluon interaction, the non-perturbative quark-gluon interaction, and the non-perturbative quark-gluon-pion anomalous chromomagnetic interaction. The non-perturbative interactions are related to the existence of the instantons, strong topological fluctuations of gluon fields, in the QCD vacuum. At the second step, the convolution model is applied to derive the gluon distributions in the nucleon. A very important role of the pion field in producing the unpolarized and the polarized gluon distributions in the hadrons is discovered. We discuss a possible solution of the proton spin problem.

  6. Natural amyloid-β oligomers acutely impair the formation of a contextual fear memory in mice.

    Kara A Kittelberger

    Full Text Available Memory loss is one of the hallmark symptoms of Alzheimer's disease (AD. It has been proposed that soluble amyloid-beta (Abeta oligomers acutely impair neuronal function and thereby memory. We here report that natural Abeta oligomers acutely impair contextual fear memory in mice. A natural Abeta oligomer solution containing Abeta monomers, dimers, trimers, and tetramers was derived from the conditioned medium of 7PA2 cells, a cell line that expresses human amyloid precursor protein containing the Val717Phe familial AD mutation. As a control we used 7PA2 conditioned medium from which Abeta oligomers were removed through immunodepletion. Separate groups of mice were injected with Abeta and control solutions through a cannula into the lateral brain ventricle, and subjected to fear conditioning using two tone-shock pairings. One day after fear conditioning, mice were tested for contextual fear memory and tone fear memory in separate retrieval trials. Three experiments were performed. For experiment 1, mice were injected three times: 1 hour before and 3 hours after fear conditioning, and 1 hour before context retrieval. For experiments 2 and 3, mice were injected a single time at 1 hour and 2 hours before fear conditioning respectively. In all three experiments there was no effect on tone fear memory. Injection of Abeta 1 hour before fear conditioning, but not 2 hours before fear conditioning, impaired the formation of a contextual fear memory. In future studies, the acute effect of natural Abeta oligomers on contextual fear memory can be used to identify potential mechanisms and treatments of AD associated memory loss.

  7. Formation of soluble amyloid oligomers and amyloid fibrils by the multifunctional protein vitronectin

    Langen Ralf

    2008-10-01

    Full Text Available Abstract Background The multifunctional protein vitronectin is present within the deposits associated with Alzheimer disease (AD, age-related macular degeneration (AMD, atherosclerosis, systemic amyloidoses, and glomerulonephritis. The extent to which vitronectin contributes to amyloid formation within these plaques, which contain misfolded, amyloidogenic proteins, and the role of vitronectin in the pathophysiology of the aforementioned diseases is currently unknown. The investigation of vitronectin aggregation is significant since the formation of oligomeric and fibrillar structures are common features of amyloid proteins. Results We observed vitronectin immunoreactivity in senile plaques of AD brain, which exhibited overlap with the amyloid fibril-specific OC antibody, suggesting that vitronectin is deposited at sites of amyloid formation. Of particular interest is the growing body of evidence indicating that soluble nonfibrillar oligomers may be responsible for the development and progression of amyloid diseases. In this study we demonstrate that both plasma-purified and recombinant human vitronectin readily form spherical oligomers and typical amyloid fibrils. Vitronectin oligomers are toxic to cultured neuroblastoma and retinal pigment epithelium (RPE cells, possibly via a membrane-dependent mechanism, as they cause leakage of synthetic vesicles. Oligomer toxicity was attenuated in RPE cells by the anti-oligomer A11 antibody. Vitronectin fibrils contain a C-terminal protease-resistant fragment, which may approximate the core region of residues essential to amyloid formation. Conclusion These data reveal the propensity of vitronectin to behave as an amyloid protein and put forth the possibilities that accumulation of misfolded vitronectin may contribute to aggregate formation seen in age-related amyloid diseases.

  8. PrP(Sc-specific antibodies with the ability to immunodetect prion oligomers.

    Mourad Tayebi

    Full Text Available The development of antibodies with binding capacity towards soluble oligomeric forms of PrPSc recognised in the aggregation process in early stage of the disease would be of paramount importance in diagnosing prion diseases before extensive neuropathology has ensued. As blood transfusion appears to be efficient in the transmission of the infectious prion agent, there is an urgent need to develop reagents that would specifically recognize oligomeric forms of the abnormally folded prion protein, PrPSc.To that end, we show that anti-PrP monoclonal antibodies (called PRIOC mAbs derived from mice immunised with native PrP-coated microbeads are able to immunodetect oligomers/multimers of PrPSc. Oligomer-specific immunoreactivity displayed by these PRIOC mAbs was demonstrated as large aggregates of immunoreactive deposits in prion-permissive neuroblastoma cell lines but not in equivalent non-infected or prn-p(0/0 cell lines. In contrast, an anti-monomer PrP antibody displayed diffuse immunoreactivity restricted to the cell membrane. Furthermore, our PRIOC mAbs did not display any binding with monomeric recombinant and cellular prion proteins but strongly detected PrPSc oligomers as shown by a newly developed sensitive and specific ELISA. Finally, PrioC antibodies were also able to bind soluble oligomers formed of Aβ and α-synuclein. These findings demonstrate the potential use of anti-prion antibodies that bind PrPSc oligomers, recognised in early stage of the disease, for the diagnosis of prion diseases in blood and other body fluids.

  9. Amyloid β oligomers elicit mitochondrial transport defects and fragmentation in a time-dependent and pathway-specific manner.

    Rui, Yanfang; Zheng, James Q

    2016-01-01

    Small oligomeric forms of amyloid-β (Aβ) are believed to be the culprit for declined brain functions in AD in part through their impairment of neuronal trafficking and synaptic functions. However, the precise cellular actions of Aβ oligomers and underlying mechanisms in neurons remain to be fully defined. Previous studies have identified mitochondria as a major target of Aβ toxicity contributing to early cognitive decline and memory loss in neurodegenerative diseases including Alzheimer's disease (AD). In this study, we report that Aβ oligomers acutely elicit distinct effects on the transport and integrity of mitochondria. We found that acute exposure of hippocampal neurons to Aβ oligomers from either synthetic peptides or AD brain homogenates selectively impaired fast transport of mitochondria without affecting the movement of late endosomes and lysosomes. Extended exposure of hipoocampal neurons to Aβ oligomers was found to result in mitochondrial fragmentation. While both mitochondrial effects induced by Aβ oligomers can be abolished by the inhibition of GSK3β, they appear to be independent from each other. Aβ oligomers impaired mitochondrial transport through HDAC6 activation whereas the fragmentation involved the GTPase Drp-1. These results show that Aβ oligomers can acutely disrupt mitochondrial transport and integrity in a time-dependent and pathway-specific manner. These findings thus provide new insights into Aβ-induced mitochondrial defects that may contribute to neuronal dysfunction and AD pathogenesis. PMID:27535553

  10. Hypoglycemic activities of A- and B-type procyanidin oligomer-rich extracts from different Cinnamon barks.

    Lu, Zhaolian; Jia, Qi; Wang, Rui; Wu, Ximin; Wu, Yingchun; Huang, Caiguo; Li, Yiming

    2011-02-15

    Procyanidin oligomers in Cinnamon are thought to be responsible for the biological activity in the treatment of diabetes mellitus (DM). To clarify types of procyanidin oligomers in different Cinnamon species and investigate their different effects, the present study investigated procyanidin oligomers in polyphenolic oligomer-rich extracts of three Cinnamon samples by LC-MS methods, and their hypoglycemic activities were detected in vivo and in vitro. The results showed that two of the three samples from Cinnamomum cassia were rich in B-type procyanidin oligomers, and the other sample was rich in A-type procyanidin oligomers. The Cinnamon extracts were administered at doses of 200 and 300 mg/kg body wt. in high-fat diet-fed and low-dose streptozotocin (STZ)-induced diabetic mice for 14 days. The results showed that blood glucose concentrations were significantly decreased in all Cinnamon extract groups compared with the control group (pCinnamon extracts significantly increased the consumption of extracellular glucose in insulin-resistant HepG2 cells and normal HepG2 cells compared with the control group. These results suggest that both A- and B-type procyanidin oligomers in different Cinnamon species have hypoglycemic activities and may improve insulin sensitivity in type 2 DM. PMID:20851586

  11. Kinetic properties of Rhizopus oryzae RPG1 endo-polygalacturonase hydrolyzing galacturonic acid oligomers

    Future fuel and specialty chemical production will benefit from the use of agricultural biomass. Efficient and effective use of agricultural biomass requires conversion to simple sugars by chemical pre-treatments and enzymes into simple sugars. Rhizopus oryzae, a filamentous fungus, makes enzymes ca...

  12. Microflora dynamics in earthworms casts in an artificial soil (biosynthesol containing lactic acid oligomers

    Alauzet Nathalie

    2001-01-01

    Full Text Available Studies were performed to appreciate the presence of micro-organisms able to degrade OLA, in earthworms casts or in the surroundings. Worms were grown in biosynthesol, an artificial soil. The counting of bacteria and fungi in earthworms casts and in biosynthesol without earthworms suggested that earthworms ate some of the micro-organisms. The main filamentous fungi genera found were Aspergillus, Trichoderma, Fusarium and Penicillium. Previous results in the literature have shown that some species from the Aspergillus and Fusarium genera were able to degrade OLA and other aliphatic esters. It could be suggested that these two genera and some bacteria were responsible for the pre-degradation of OLA, and that earthworms might eat them.

  13. The flavonoid herbacetin diglucoside as a constituent of the lignan macromolecule from flaxseed hulls

    Struijs, K.; Vincken, J.P.; Verhoef, R.P.; Oostveen, van W.H.M.; Voragen, A.G.J.; Gruppen, H.

    2007-01-01

    Lignans in flaxseed are known to be part of a macromolecule in which they are connected through the linker-molecule hydroxy-methyl-glutaric acid (HMGA). In this study, the lignan macromolecule was extracted from flaxseed hulls and degraded to its monomeric constituents by complete saponification. Be

  14. Kavain, the Major Constituent of the Anxiolytic Kava Extract, Potentiates GABAA Receptors

    Chua, Han Chow; Christensen, Emilie H T; Hoestgaard-Jensen, Kirsten;

    2016-01-01

    Extracts of the pepper plant kava (Piper methysticum) are effective in alleviating anxiety in clinical trials. Despite the long-standing therapeutic interest in kava, the molecular target(s) of the pharmacologically active constituents, kavalactones have not been established. γ-Aminobutyric acid ...

  15. Acyl secoiridoids and antifungal constituents from Gentiana macrophylla.

    Tan, R X; Wolfender, J L; Zhang, L X; Ma, W G; Fuzzati, N; Marston, A; Hostettmann, K

    1996-07-01

    LC-UV-mass spectrometry and bioassay co-directed fractionation of an aqueous acetone extract of the roots of Gentiana macrophylla gave three new chromene derivatives and two novel and six known secoiridoids, along with kurarinone, kushenol I, beta-sitosterol, stigmasterol, daucosterol, beta-sitosterol-3-O-gentiobioside, alpha-amyrin, oleanolic acid, isovitexin, gentiobiose and methyl 2-hydroxy-3-(1-beta-D-glucopyranosyl)oxybenzoate. The structures of the new products were established from spectral and chemical evidence as 2-methoxyanofinic acid and macrophyllosides A-D. The six known secoiridoids were gentiopicroside, sweroside, 6'-O-beta-D-glucosylgentiopicroside, 6'-O-beta-D-glucosylsweroside, trifloroside and rindoside. The new acid (2-methoxyanofinic acid), its methyl ester, kurarinone and kushenol I were shown to be active against the plant pathogenic fungus Cladosporium cucumerinum. The methyl ester and kurarinone inhibited also the growth of the human pathogenic yeast Candida albicans. Structure-activity relationships were studied. Thus, addition of a methoxyl group to the benzene nucleus of anofinic acid (2,2-dimethyl-2H-1-benzopyran-6-carboxylic acid) increased the antifungal activity remarkably whereas glycosylation at the carboxylic moiety was found to remove the activity. Esterification of the new acid induced its activity against C. albicans, but decreased its growth inhibition properties against C. cucumerinum. Hydroxylation of kurarinone at the 3 beta-position removed its activity against C. albicans and decreased the inhibition of C. cucumerinum. In addition, the chemotaxonomic significance of the identified constituents is discussed. PMID:9397205

  16. Phytochemical constituents of some Indian medicinal plants

    Dhandapani, R.; Sabna, B.

    2008-01-01

    Alkaloids, tannins, saponins, steroid, terpenoid, flavonoids, phlobatannin and cardie glycoside distribution in seven medicinal plants belonging to different families were assessed and compared. The medicinal plants investigated were Aegle marmelos, Cynodon dactylon, Eclipta prostrata, Moringa pterygosperma, Pongamia pinnata, Sida acuta and Tridax procumbens. The significance of the plants in traditional medicine and the importance of the distribution of these chemical constituents were discu...

  17. Patch testing with constituents of Compositae mixes

    Paulsen, Evy; Andersen, Klaus Ejner

    2012-01-01

    Background. The development of mixes containing Compositae plant extracts has improved the diagnosis of Compositae contact allergy, but none of them has fulfilled the criteria for an ideal European plant mix. Objective. To evaluate which constituents of two commercial Compositae mixes were most u...

  18. Hyperon polarization in the constituent quark model

    A mechanism for hyperon polarization in the inclusive production is considered. The main role belongs to the orbital angular momentum and polarization of strange quark-antiquark pairs in the internal structure of constituent quarks. The nonperturbative hadron structure is based on the results of chiral quark models

  19. Constituent quark description of nucleon structure

    Nucleon structure functions are calculated within the constituent quark in the leading order. The results compare well with the experimental data for entire range of kinematics in x and Q2and with the next - to - leading order calculation of GRV

  20. ASSESSING UNIVERSITY RESEARCH PERFORMANCE WITH MULTIPLE CONSTITUENCIES

    Kuang-Liang Liu; Chen-Chi Chang

    2012-01-01

    The research performance of the university is critical to the national competitiveness. Previous research has established that research performance is based on scholarly publishing. Several studies suggested that journal ranking is the important research quality indicator. However, unilateral measurement for the research performance will seriously corrode the development of university research work. Assessing university research performance with multiple constituencies is a better to enhance ...

  1. 40 CFR 264.93 - Hazardous constituents.

    2010-07-01

    ... 264.93 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Releases From Solid Waste Management Units § 264.93 Hazardous constituents. (a) The Regional Administrator...

  2. Mesons in the Constituent Quark Model

    WANG Li; PING Jia-Lun

    2007-01-01

    The quark-antiquark (q(-q)) spectrum is studied by solving the Schrǒdinger equation in the framework of non-relativistic constituent quark model. An overall good fit to the experimental data of meson is obtained. The interactions between quark and antiquark consist of quadratic colour confinement-exchange, one-gluon-exchange, and Goldstone-boson-exchange potentials.

  3. 21 CFR 610.15 - Constituent materials.

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Constituent materials. 610.15 Section 610.15 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) BIOLOGICS... culture produced vaccines. Extraneous protein known to be capable of producing allergenic effects in...

  4. Accumulation of oligomer-prone α-synuclein exacerbates synaptic and neuronal degeneration in vivo.

    Rockenstein, Edward; Nuber, Silke; Overk, Cassia R; Ubhi, Kiren; Mante, Michael; Patrick, Christina; Adame, Anthony; Trejo-Morales, Margarita; Gerez, Juan; Picotti, Paola; Jensen, Poul H; Campioni, Silvia; Riek, Roland; Winkler, Jürgen; Gage, Fred H; Winner, Beate; Masliah, Eliezer

    2014-05-01

    In Parkinson's disease and dementia with Lewy bodies, α-synuclein aggregates to form oligomers and fibrils; however, the precise nature of the toxic α-synuclein species remains unclear. A number of synthetic α-synuclein mutations were recently created (E57K and E35K) that produce species of α-synuclein that preferentially form oligomers and increase α-synuclein-mediated toxicity. We have shown that acute lentiviral expression of α-synuclein E57K leads to the degeneration of dopaminergic neurons; however, the effects of chronic expression of oligomer-prone α-synuclein in synapses throughout the brain have not been investigated. Such a study could provide insight into the possible mechanism(s) through which accumulation of α-synuclein oligomers in the synapse leads to neurodegeneration. For this purpose, we compared the patterns of neurodegeneration and synaptic damage between a newly generated mThy-1 α-synuclein E57K transgenic mouse model that is prone to forming oligomers and the mThy-1 α-synuclein wild-type mouse model (Line 61), which accumulates various forms of α-synuclein. Three lines of α-synuclein E57K (Lines 9, 16 and 54) were generated and compared with the wild-type. The α-synuclein E57K Lines 9 and 16 were higher expressings of α-synuclein, similar to α-synuclein wild-type Line 61, and Line 54 was a low expressing of α-synuclein compared to Line 61. By immunoblot analysis, the higher-expressing α-synuclein E57K transgenic mice showed abundant oligomeric, but not fibrillar, α-synuclein whereas lower-expressing mice accumulated monomeric α-synuclein. Monomers, oligomers, and fibrils were present in α-synuclein wild-type Line 61. Immunohistochemical and ultrastructural analyses demonstrated that α-synuclein accumulated in the synapses but not in the neuronal cells bodies, which was different from the α-synuclein wild-type Line 61, which accumulates α-synuclein in the soma. Compared to non-transgenic and lower-expressing mice, the

  5. Stereocomplexation in Copolymer Networks Incorporating Enantiomeric Glycerol-Based 3-Armed Lactide Oligomers and a 2-Armed ɛ-Caprolactone Oligomer

    Ayaka Shibita

    2016-07-01

    Full Text Available The reactions of enantiomeric glycerol-based 3-armed lactide oligomers (H3DLAO and H3LLAO and a diethylene glycol-based 2-armed ɛ-caprolactone oligomer (H2CLO with hexamethylene diisocyanate (HDI produced polyesterurethane copolymer networks (PEU-3scLAO/2CLOs 100/0, 75/25, 50/50, 25/75 and 0/100 with different feed ratios of stereocomplex (sc lactide oligomer (H3scLAO = H3DLAO + H3LLAO, H3DLAO/H3LLAO = 1/1 and H2CLO. Thermal and mechanical properties of the copolymer networks were compared with those of a simple homochiral (hc network (PEU-3DLAO produced by the reaction of H3DLAO and HDI. X-ray diffraction and differential scanning calorimetric analyses revealed that sc crystallites are formed without any hc crystallization for PEU-3scLAO/2CLOs, and that PEU-3DLAO is amorphous. The melting temperatures of sc crystallites for PEU-3scLAO/2CLOs were much higher than that of hc crystallites of H3DLAO. The polarized optical microscopic analysis revealed that the nucleation efficiency is enhanced with increasing feed of H3scLAO fraction, whereas the spherulite growth rate is accelerated with increasing feed H2CLO fraction over 100/0-50/50 networks. PEU-3scLAO/2CLO 100/0 (i.e., PEU-3scLAO exhibited a higher tensile strength and modulus than PEU-3DLAO. The elongation at break and tensile toughness for PEU-3scLAO/2CLOs increased with an increasing feed amount of H2CLO.

  6. Aromatic constituents in fresh leaves of Lingtou Dancong Tea induced by drought stress

    CAO Panrong; LIU Chunyan; LIU Kebin

    2007-01-01

    The effect of different degrees of drought stress on the aromatic constituents and their relative contents in fresh leaves ofLingtou Dancong tea plants was studied in this paper.The results showed that drought stress could evidently increase the kinds of aromatic components in the fresh leaves.The largest number of kinds(58)of the aromatic constituents was detected when soil relative water content was 53.90% among all the designed treatments,while the lowest number was found under a soil relative water content of 99.75%.The total amount of relative contents of 17 kinds of aromatic components such as linalool etc.,increased with drought stress,whereas 12 kinds of aromatic components such as tetradecanoic acid etc.,decreased with drought stress. Linalool,linalool oxide,tetradecane, 10-methylnonadecane, and dodecanal showed high contents under the soil relative water content of 53.90%;Cyclohexane,1-hexadecene,and 1tricosanolonly were induced in the soil relative water content of 53.90% and 29.25%;while drought stress could inhibit the synthesis of constituents of 7 kinds such as nonanedioic acid monomethyl ester,etc.Different degrees of drought stress could induce various kinds of aromatic constituents,and the number of aromatic constituents induced in fresh leaves increased with the strengthening of drought stress.

  7. Studies on Chemical Constituents From Artabotrys Hainanensis

    CHEN Guangying; SONG Xiao-Ping; HAN Chang-ri

    2004-01-01

    Artabotrys Hainanensis R.E. Fries are plants of the Annonaccac family artabotrys genus,which includes an estimated 100 types of plants distributed mainly in the tropical zone and the subtropics areas. Four types of the plants are discovered in our country, two of which, A.Hongkongensis Hance and A. hexapetalus (Linn. F.) Bhandari, in Guangdong Province, and the other two, A. Pilosus and A. Hainanensis R.E. Fries, in Hainan Province. The latter are widely distributed in Hainan Island with very rich reserves. They have long been used among the ordinary people as medicinal plants with antipyretic, antidotal, antiphlogistic and analgesic effects and are often used for malaria. Scholars from home and abroad have paid much attention to the plants of the Annonaccac family for their containing anti-tumor activities, and after early or late research of the chemical constituents of the root, stem (derm), leaf and fruit of many types of plants of Artabotrys genus, more than 40 compounds including alkaloid, flavone and terpenoid have been isolated and obtained. Artabotrys Hainanensis R.E. Fries are Hainan endemic plants and there has been no report on the research of their chemical constituents and biological activities so far. In order to find new constituents of pharmacologic activity, we have researched the chemical constituents of the leaf and stem.The crude drugs were collected from Hainan Jianfeng Mountain and were identified as Artabotrys Hainanensis R.E. Fries of the Annonaccac family artabotrys genus. Its sample specimen is now kept in Chemistry Department of Hainan Normal University.After isolation and identification of constituent, six compounds were isolated from the leaf of Artabotrys Hainanensis R.E. Fries and elucidated as β -sitosterol (Ⅰ), catechin (Ⅱ), mangiferin (Ⅲ),(Ⅳ), (Ⅴ), (Ⅵ). All the compounds were obtained from this plant for the first time. Compounds Ⅱ, Ⅲ,Ⅳ, Ⅴ and Ⅵ were obtained from the genus of Artabotrys for the first time.

  8. Amyloid β oligomers induce interleukin-1β production in primary microglia in a cathepsin B- and reactive oxygen species-dependent manner

    Amyloid β (Aβ) peptide, a causative agent of Alzheimer's disease, forms two types of aggregates: oligomers and fibrils. These aggregates induce inflammatory responses, such as interleukin-1β (IL-1β) production by microglia, which are macrophage-like cells located in the brain. In this study, we examined the effect of the two forms of Aβ aggregates on IL-1β production in mouse primary microglia. We prepared Aβ oligomer and fibril from Aβ (1–42) peptide in vitro. We analyzed the characteristics of these oligomers and fibrils by electrophoresis and atomic force microscopy. Interestingly, Aβ oligomers but not Aβ monomers or fibrils induced robust IL-1β production in the presence of lipopolysaccharide. Moreover, Aβ oligomers induced endo/phagolysosome rupture, which released cathepsin B into the cytoplasm. Aβ oligomer-induced IL-1β production was inhibited not only by the cathepsin B inhibitor CA-074-Me but also by the reactive oxygen species (ROS) inhibitor N-acetylcysteine. Random chemical crosslinking abolished the ability of the oligomers to induce IL-1β. Thus, multimerization and fibrillization causes Aβ oligomers to lose the ability to induce IL-1β. These results indicate that Aβ oligomers, but not fibrils, induce IL-1β production in primary microglia in a cathepsin B- and ROS-dependent manner. - Highlights: • We prepared amyloid β (Aβ) fibrils with minimum contamination of Aβ oligomers. • Primary microglia (MG) produced IL-1β in response to Aβ oligomers, but not fibrils. • Only Aβ oligomers induced leakage of cathepsin B from endo/phagolysosomes. • IL-1β production in response to Aβ oligomers depended on both cathepsin B and ROS. • Crosslinking reduced the ability of the Aβ oligomers to induce IL-1β from MG

  9. Amyloid β oligomers induce interleukin-1β production in primary microglia in a cathepsin B- and reactive oxygen species-dependent manner

    Taneo, Jun; Adachi, Takumi [Department of Animal Development and Physiology, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto 606-8501 (Japan); Yoshida, Aiko; Takayasu, Kunio [Responses to Environmental Signals and Stresses, Graduate School of Biostudies, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto, Kyoto 606-8501 (Japan); Takahara, Kazuhiko, E-mail: ktakahar@zoo.zool.kyoto-u.ac.jp [Department of Animal Development and Physiology, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto 606-8501 (Japan); Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), Tokyo 102-0081 (Japan); Inaba, Kayo [Department of Animal Development and Physiology, Kyoto University, Yoshida-Konoe, Sakyo, Kyoto 606-8501 (Japan); Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), Tokyo 102-0081 (Japan)

    2015-03-13

    Amyloid β (Aβ) peptide, a causative agent of Alzheimer's disease, forms two types of aggregates: oligomers and fibrils. These aggregates induce inflammatory responses, such as interleukin-1β (IL-1β) production by microglia, which are macrophage-like cells located in the brain. In this study, we examined the effect of the two forms of Aβ aggregates on IL-1β production in mouse primary microglia. We prepared Aβ oligomer and fibril from Aβ (1–42) peptide in vitro. We analyzed the characteristics of these oligomers and fibrils by electrophoresis and atomic force microscopy. Interestingly, Aβ oligomers but not Aβ monomers or fibrils induced robust IL-1β production in the presence of lipopolysaccharide. Moreover, Aβ oligomers induced endo/phagolysosome rupture, which released cathepsin B into the cytoplasm. Aβ oligomer-induced IL-1β production was inhibited not only by the cathepsin B inhibitor CA-074-Me but also by the reactive oxygen species (ROS) inhibitor N-acetylcysteine. Random chemical crosslinking abolished the ability of the oligomers to induce IL-1β. Thus, multimerization and fibrillization causes Aβ oligomers to lose the ability to induce IL-1β. These results indicate that Aβ oligomers, but not fibrils, induce IL-1β production in primary microglia in a cathepsin B- and ROS-dependent manner. - Highlights: • We prepared amyloid β (Aβ) fibrils with minimum contamination of Aβ oligomers. • Primary microglia (MG) produced IL-1β in response to Aβ oligomers, but not fibrils. • Only Aβ oligomers induced leakage of cathepsin B from endo/phagolysosomes. • IL-1β production in response to Aβ oligomers depended on both cathepsin B and ROS. • Crosslinking reduced the ability of the Aβ oligomers to induce IL-1β from MG.

  10. Structural requirements for the procoagulant activity of nucleic acids.

    Julia Gansler

    Full Text Available Nucleic acids, especially extracellular RNA, are exposed following tissue- or vessel damage and have previously been shown to activate the intrinsic blood coagulation pathway in vitro and in vivo. Yet, no information on structural requirements for the procoagulant activity of nucleic acids is available. A comparison of linear and hairpin-forming RNA- and DNA-oligomers revealed that all tested oligomers forming a stable hairpin structure were protected from degradation in human plasma. In contrast to linear nucleic acids, hairpin forming compounds demonstrated highest procoagulant activities based on the analysis of clotting time in human plasma and in a prekallikrein activation assay. Moreover, the procoagulant activities of the DNA-oligomers correlated well with their binding affinity to high molecular weight kininogen, whereas the binding affinity of all tested oligomers to prekallikrein was low. Furthermore, four DNA-aptamers directed against thrombin, activated protein C, vascular endothelial growth factor and nucleolin as well as the naturally occurring small nucleolar RNA U6snRNA were identified as effective cofactors for prekallikrein auto-activation. Together, we conclude that hairpin-forming nucleic acids are most effective in promoting procoagulant activities, largely mediated by their specific binding to kininogen. Thus, in vivo application of therapeutic nucleic acids like aptamers might have undesired prothrombotic or proinflammatory side effects.

  11. Leaching of DOC, DN, and inorganic constituents from scrap tires.

    Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

    2015-11-01

    One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse. PMID:25712610

  12. Covalent bonding of chloroanilines to humic constituents: Pathways, kinetics, and stability

    Covalent coupling to natural humic constituents comprises an important transformation pathway for anilinic pollutants in the environment. We systematically investigated the reactions of chlorine substituted anilines with catechol and syringic acid in horseradish peroxidase (HRP) catalyzed systems. It was demonstrated that although nucleophilic addition was the mechanism of covalent bonding to both catechol and syringic acid, chloroanilines coupled to the 2 humic constituents via slightly different pathways. 1,4-addition and 1,2-addition are involved to catechol and syringic acid, respectively. 1,4-addition showed empirical 2nd order kinetics and this pathway seemed to be more permanent than 1,2-addition. Stability experiments demonstrated that cross-coupling products with syringic acid could be easily released in acidic conditions. However, cross-coupling with catechol was relatively stable at similar conditions. Thus, the environmental behavior and bioavailability of the coupling products should be carefully assessed. -- Highlights: •Chloroanilines covalently coupled to humic constituents in HRP catalyzed processes, which facilitated their transformation. •MS technique was employed to analyze the coupling products and therefore elucidate the reaction pathways. •Chloroanilines couple to catechol and syringic acid via 1,4- and 1,2-nucleophilic addition pathways, respectively. •Cross-coupling products formed via 1,4-nucleophilic addition pathway were more stable than those via 1,2-addition pathway. -- Bound residues of chloroanilines formed via 1,2- and 1,4-nucleophilic addition pathways showed different stability

  13. Electrical detection of dengue virus (DENV) DNA oligomer using silicon nanowire biosensor with novel molecular gate control.

    Nuzaihan M N, M; Hashim, U; Md Arshad, M K; Kasjoo, S R; Rahman, S F A; Ruslinda, A R; Fathil, M F M; Adzhri, R; Shahimin, M M

    2016-09-15

    In this paper, a silicon nanowire biosensor with novel molecular gate control has been demonstrated for Deoxyribonucleic acid (DNA) detection related to dengue virus (DENV). The silicon nanowire was fabricated using the top-down nanolithography approach, through nanostructuring of silicon-on-insulator (SOI) layers achieved by combination of the electron-beam lithography (EBL), plasma dry etching and size reduction processes. The surface of the fabricated silicon nanowire was functionalized by means of a three-step procedure involving surface modification, DNA immobilization and hybridization. This procedure acts as a molecular gate control to establish the electrical detection for 27-mers base targets DENV DNA oligomer. The electrical detection is based on the changes in current, resistance and conductance of the sensor due to accumulation of negative charges added by the immobilized probe DNA and hybridized target DNA. The sensitivity of the silicon nanowire biosensors attained was 45.0µAM(-1), which shows a wide-range detection capability of the sensor with respect to DNA. The limit of detection (LOD) achieved was approximately 2.0fM. The demonstrated results show that the silicon nanowire has excellent properties for detection of DENV with outstanding repeatability and reproducibility performances. PMID:27107147

  14. Electrospray mass spectrometry of NeuAc oligomers associated with the C fragment of the tetanus toxin

    Prieto, M C; Whittal, R M; Baldwin, M A; Burlingame, A L; Balhorn, R

    2005-04-03

    The Clostridial neurotoxins, botulinum and tetanus, gain entry into neuronal cells by protein recognition involving cell specific binding sites. The sialic or N-acetylneuraminic acid (NeuAc) residues of gangliosides attached to the surface of motor neurons are the suspected recognition and interaction points with Clostridial neurotoxins, although not necessarily the only ones. We have used electrospray ionization mass spectrometry (ESIMS) to examine formation of complexes between the tetanus toxin C fragment, or targeting domain, and carbohydrates containing NeuAc groups to determine how NeuAc residues contribute to ganglioside binding. ESI-MS was used to rapidly and efficiently measure dissociation constants for a number of related NeuAc-containing carbohydrates and NeuAc oligomers, information that has helped identify the structural features of gangliosides that determine their binding to tetanus toxin. The strength of the interactions between the C fragment and (NeuAc){sub n}, are consistent with the topography of the targeting domain of tetanus toxin and the nature of its carbohydrate binding sites. The results suggest that the targeting domain of tetanus toxin contains two binding sites that can accommodate NeuAc (or a dimer). This study also shows that NeuAc must play an important role in ganglioside binding and molecular recognition, a process critical for normal cell function and one frequently exploited by toxins, bacteria and viruses to facilitate their entrance into cells.

  15. Combinatorial Synthesis, Screening, and Binding Studies of Highly Functionalized Polyamino-amido Oligomers for Binding to Folded RNA

    Jonathan K. Pokorski

    2012-01-01

    Full Text Available Folded RNA molecules have recently emerged as critical regulatory elements in biological pathways, serving not just as carriers of genetic information but also as key components in enzymatic assemblies. In particular, the transactivation response element (TAR of the HIV genome regulates transcriptional elongation by interacting specifically with the Tat protein, initiating the recruitment of the elongation complex. Preventing this interaction from occurring in vivo halts HIV replication, thus making RNA-binding molecules an intriguing pharmaceutical target. Using α-amino acids as starting materials, we have designed and synthesized a new class of polyamino-amido oligomers, called PAAs, specifically for binding to folded RNA structures. The PAA monomers were readily incorporated into a 125-member combinatorial library of PAA trimers. In order to rapidly assess RNA binding, a quantum dot-based fluorescent screen was developed to visualize RNA binding on-resin. The binding affinities of hits were quantified using a terbium footprinting assay, allowing us to identify a ligand (SFF with low micromolar affinity (kd=14 μM for TAR RNA. The work presented herein represents the development of a flexible scaffold that can be easily synthesized, screened, and subsequently modified to provide ligands specific for binding to folded RNAs.

  16. Fluorescent oligomer as a chemosensor for the label-free detection of Fe(3+) and dopamine with selectivity and sensitivity.

    Zhao, Lingli; Xin, Xia; Ding, Peng; Song, Aixin; Xie, Zengchun; Shen, Jinglin; Xu, Guiying

    2016-07-01

    In this article, a sensitive and selective turn-off fluorescence chemosensor, Tyloxapol (one kind of water soluble oligomer), was developed for the label-free detection of Fe(3+) ions in aqueous solution. Fluorescence (FL) experiments demonstrated that Tyloxapol was a sensitive and selective fluorescence sensor for the detection of Fe(3+) directly in water over a wide range of metal cations including Na(+), K(+), Ag(+), Hg(2+), Cd(2+), Co(2+), Cu(2+), Cr(3+), Mn(2+), Ba(2+), Zn(2+), Ni(2+), Mg(2+), Ca(2+), and Pb(2+). Moreover, the fluorescence intensity of Tyloxapol has shown a linear response to Fe(3+) in the concentration range of 0-100 μmol L(-1) with a detection limit of 2.2 μmol L(-1) in aqueous solution. Next, based on a competition mechanism, another turn-on sensing application of the Tyloxapol/Fe(3+) platform to probe dopamine (DA) against various other biological molecules such as other neurotransmitters or amino acids (norepinephrine bitartrate, acetylcholine chloride, alanine, valine, phenylalanine, tyrosine, leucine, glycine, histidine) were also investigated. It is expected that our strategy may offer a new approach for developing simple, cost-effective, rapid and sensitive sensors in biological and environmental applications. PMID:27216398

  17. [Chemical constituents of Taraxacum sinicum Kitag].

    Ling, Y; Zhang, Y; Cai, S; Xiao, Y; Cai, S; Zheng, J

    1998-04-01

    Five compounds were separated from Taraxacum sinicum by means of solvent extraction and rechromatography on silical gel. Their structures were established as caffeic acid, ferulic acid, chlorogenic acid, luteolin and diosmetin by spectral analysis and chemical evidence. All the compounds were isolated from this plant for the first time. Chlorogenic acid and diosmetin have not been discovered from Taraxacum genus previously. PMID:11596250

  18. Detection of Aspergillus fumigatus pulmonary fungal infections in mice with 99mTc-labeled MORF oligomers targeting ribosomal RNA

    Purpose: Invasive aspergillosis is a major cause of infectious morbidity and mortality in immunocompromised patients. The fungus Aspergillus fumigatus (A. fumigatus) is the primary causative agent of invasive aspergillosis. However, A. fumigatus infections remain difficult to diagnose particularly in the early stages due to the lack of a rapid, sensitive and specific diagnostic approach. In this study, we investigated 99mTc labeled MORF oligomers targeting fungal ribosomal RNA (rRNA) for the imaging detection of fungal infections. Procedures: Three phosphorodiamidate morpholino (MORF) oligomer (a DNA analogue) probes were designed: AGEN, complementary to a sequence of the fungal 28S ribosomal RNA (rRNA) of Aspergillus, as a genus-specific probe; AFUM, complementary to the 28S rRNA sequence of A. fumigatus, as a fungus species-specific probe; and cMORF, irrelevant to all fungal species, as a control probe. The probes were conjugated with Alexa Fluor 633 carboxylic acid succinimidyl ester (AF633) for fluorescence imaging or with NHS-mercaptoacetyl triglycine (NHS-MAG3) for nuclear imaging with 99mTc and then evaluated in vitro and in vivo. Results: The specific binding of AGEN and AFUM to fungal total RNA was confirmed by dot blot hybridization while specific binding of AGEN and AFUM in fixed and live A. fumigatus was demonstrated by both fluorescent in situ hybridization (FISH) analysis and accumulation in live cells. SPECT imaging of BALB/c mice with pulmonary A. fumigatus infections and administered 99mTc labeled AGEN and AFUM showed immediate and obvious accumulation in the infected lungs, while no significant accumulation of the control 99mTc-cMORF in the infected lung was observed. Compared to non-infected mice, with sacrifice at 1 h, the accumulation of 99mTc-AGEN and 99mTc-AFUM in the lungs of mice infected with A. fumigatus was 2 and 2.7 fold higher respectively. Conclusions: In vivo targeting fungal ribosomal RNA with 99mTc labeled MORF probes AGEN and AFUM

  19. ANTICANCER ACTIVITY OF ISOLATED CHEMICAL CONSTITUENTS FROM MILIUSA SMITHIAE

    Chonthicha Naphong

    2013-01-01

    Full Text Available Miliusa plants belonging to the family Annonaceae are found in Thailand and have been used as Thai traditional medicines. There have been a few previously reports on the chemical constituents of plants in this genus, describing the presence of aporphine alkaloids, terpenoids, flavonoids, phenylpropanoids, styrylpyrones, bis-styryls and homogentisic acid derivatives. Miliusa smithiae, a new species for Thailand and world, has not been studied chemical composition. The present study described phytochemical study of the leaves and twigs of M. smithiae together with their cytotoxicity. The M. smithiae was selected and percolated with hexane, ethyl acetate, acetone and methanol. The extracts were purified and elucidated chemical structures. The constituent of ethyl acetate extract of M. smithiae has been investigated. We isolated and identified two flavonoid derivatives, 5-hydroxy-3,7,4′-trimetoxyflavone (1 and 5,3′-dihydroxy-3,7,4′-trimetoxyflavone (2. The structures of these compounds were elucidated on the basis of spectroscopic evidence. Studies on ethyl acetate extract of M. smithiae has now resulted the isolation and structural characterization of two flavonoids. Their anticancer activities were evaluated using SRB assays. In this method, compound 2 showed potential activity in cell lines.

  20. Leachability of radioactive constituents from uranium mine tailings

    A project was carried out using lysimeters to determine the leaching of radioactive constituents and BaRaSO4 from abandoned uranium mine tailings. Lime addition to the surface of acidic abandoned tailings did not reduce the level of radioactive constituents in the leachate. Considerable increases in levels of the radionuclides 230Th, 232Th and 22/8Th, as well as gross alpha and beta activity in the leachate, occurred five months after recycling of BaRaSO4 sediments to the surface layers of abandoned tailings. After nine months of leaching, the levels of 226Ra in the leachate were 30% greater than the tailings plus sediment treatment than from tailings only (control). Another experiment compared the quality of effluent flowing over chemically-fixed (solidified) BaRaSO4 sediments with that of non-fixed (control) in simulated sedimentation ponds. During seven months the release of 226 Ra to water from chemically-fixed BaRaSO4 sediments remained 3 for phosphorus removal) was applied to supply 3 percent organic matter in the top 15 cm of the revegetated lysimeters. Undiluted effluent and leachate from chemically-fixed BaRaSO4 sediments and fresh tailings were 100 percent lethal to Daphnia pulex and rainbow trout (Salmo gairdneri) in static 96-hour bioassay tests. Diluted (50 percent) effluent samples were non-toxic. (auth)

  1. A new biocompatible nanocomposite as a promising constituent of sunscreens.

    Amin, Rehab M; Elfeky, Souad A; Verwanger, Thomas; Krammer, Barbara

    2016-06-01

    Skin naturally uses antioxidants to protect itself from the damaging effects of sunlight. If this is not sufficient, other measures have to be taken. Like this, hydroxyapatite has the potential to be applied as an active constituent of sunscreens since calcium phosphate absorbs in the ultraviolet region (UV). The objective of the present work was to synthesize a hydroxyapatite-ascorbic acid nanocomposite (HAp/AA-NC) as a new biocompatible constituent of sunscreens and to test its efficiency with skin cell models. The synthesized HAp/AA-NC was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, absorption spectrophotometry and X-ray diffraction analysis. The protective effect of the construct was tested with respect to viability and intracellular reactive oxygen species (ROS) generation of primary human dermal fibroblasts (SKIN) and human epidermal keratinocytes (HaCaT). Both cell lines were irradiated with UV light, λmax=254 nm with a fluence of 25 mJ cm(-2) to mimic the effect of UV radiation of sunlight on the skin. Results showed that HAp/AA-NC had a stimulating effect on the cell viability of both, HaCaT and SKIN cells, relative to the irradiated control. Intracellular ROS significantly decreased in UV irradiated cells when treated with HAp/AA-NC. We conclude that the synthesized HAp/AA-NC have been validated in vitro as a skin protector against the harmful effect of UV-induced ROS. PMID:27040194

  2. The Cytotoxic Constituents from Marine-derived Streptomyces 3320#

    2006-01-01

    The present work studies the chemical constituents from marine-derived streptomyces 3320# and their antitumor activities. The n-BuOH extract of the ferment broth of 3320# was chromatographed on silica gel, Sephadex LH-20, ODS columns and HPLC to separate the compounds with antitoumor activities. Their structures were identified using IR, UV, NMR, MS spectroscopic techniques and compared with published data. The antitumor activities of the isolates were assayed using SRB method and flow cytometry assay, accompanied with the morphological observation of the cells under light microscope against mammalian tsFT210 cells. Ten compounds, cyclo-(Ala-Leu) 1, cyclo-(Ala-Ile) 2, cyclo-(Ala-Val) 3, cyclo-(Phe- Pro) 4, cyclo-(Phe-Gly) 5, cyclo-(Leu-Pro) 6, 1-methyl-1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylic acid 7, N-(4-hydroxyphenethyl) acetamide 8, 4-methyoxy-1-(2-hydroxy) ethylbenzene 9 and uridine 10, were isolated from the ferment broth of streptomyces 3320#. Among them, compounds 6, 7, 8 and 10 showed potent cytotoxicity against the tsFT210 cell with the IC50 values of 3 . 6, 7 . 2, 5 . 2 and 1 . 6 mmol L - 1, respectively. Compounds 8, 10 also exhibited apoptosis inducing activity under 2 . 0 mmol L - 1. Compounds 6, 7, 8 and 10 are the principle bioactive constituents responsible for the antitumor activities of marine streptomyces 3320# . Compound 7 was isolated from this species for the first time.

  3. Sequence-Defined Oligomers from Hydroxyproline Building Blocks for Parallel Synthesis Applications.

    Kanasty, Rosemary L; Vegas, Arturo J; Ceo, Luke M; Maier, Martin; Charisse, Klaus; Nair, Jayaprakash K; Langer, Robert; Anderson, Daniel G

    2016-08-01

    The functionality of natural biopolymers has inspired significant effort to develop sequence-defined synthetic polymers for applications including molecular recognition, self-assembly, and catalysis. Conjugation of synthetic materials to biomacromolecules has played an increasingly important role in drug delivery and biomaterials. We developed a controlled synthesis of novel oligomers from hydroxyproline-based building blocks and conjugated these materials to siRNA. Hydroxyproline-based monomers enable the incorporation of broad structural diversity into defined polymer chains. Using a perfluorocarbon purification handle, we were able to purify diverse oligomers through a single solid-phase extraction method. The efficiency of synthesis was demonstrated by building 14 unique trimers and 4 hexamers from 6 diverse building blocks. We then adapted this method to the parallel synthesis of hundreds of materials in 96-well plates. This strategy provides a platform for the screening of libraries of modified biomolecules. PMID:27365192

  4. Preparation and NMR characterization of glucosamine oligomers bearing an azide function using chitosan.

    Maria Marzaioli, Alberto; Bedini, Emiliano; Lanzetta, Rosa; Perino, Vincenzo; Parrilli, Michelangelo; De Castro, Cristina

    2012-10-01

    In this study, a procedure to produce glucosamine oligomers with the amino functions transformed into azido groups was optimized, and HPLC purification afforded to the isolation of nine different oligosaccharides derivatives, with the reducing end transformed in alditol. These oligomers differed for the degree of polymerization and for the type of alditol at the reducing end. The first group comprehended species from di- to hexasaccharide, with all the amino functions converted into an azido group. The second and the third groups were isolated in minor yields, and were both constituted from tri- and tetrasaccharides; the difference between the two groups regarded exclusively the type of alditol found at the reducing end, which was a glucosaminitol in the first case, or a N-acetylglucosaminitol in the other. Products were fully characterized by 2D NMR spectroscopy. The azido moieties installed on these oligosaccharides can be further exploited in Cu(I) catalyzed azido-alkyne cycloaddition reactions. PMID:22840011

  5. Similarities and differences in the influence of polycations and oligomers on DNA conformation and packaging.

    Kasyanenko, Nina; Dribinsky, Boris

    2016-05-01

    A comparison of DNA conformational changes in a solution containing the poly-l-lysine with the number of monomers z=3, 5, 17, 20, 270, 325 and polyamines (spermine and spermidine) was carried out in 1M and 5mM NaCl solutions. It was shown that despite the identical results of DNA condensation induced by compounds, their influence on the DNA conformation prior to packaging depends on whether they belong to a long polycations or short oligomers. DNA secondary and tertiary structures were examined using Circular Dichroism, UV-vis Spectrophotometry, Dynamic Light Scattering, Low Gradient Viscometry, Flow Birefringence, and AFM. The phase diagrams for systems of DNA-polycations, DNA-oligomers, DNA-polyamines were drawn. PMID:26780466

  6. Highly durable and efficient quantum dot-sensitized solar cells based on oligomer gel electrolytes.

    Kim, Heejin; Hwang, Insung; Yong, Kijung

    2014-07-23

    For stable quantum dot-sensitized solar cells, an oligomer-contained gel electrolyte was employed with a carbon-based counter electrode and a hierarchically shelled ZnO photoelectrode. Poly(ethylene glycol) dimethyl-ether (PEGDME) was added to the polysulfide electrolyte to enhance the stability of the methanol-based electrolyte. In addition, the nanocomposite gel electrolyte with fumed silica was used, which provided a solid three-dimensional network. A quantum-dot-modified ZnO nanowire photoanode enhanced the visible light harvesting, and a Pt/CNT-RGO counter electrode increased the catalytic activity. The oligomer gel electrolyte prevented the liquid electrolyte from leaking, and the carbon-based counter electrode retarded chemical poisoning at the counter electrode. The optimized cell exhibited 5.45% photoelectric conversion efficiency with long-term stability demonstrated over 5000 s operation time. PMID:24987930

  7. "Nail" and "comb" effects of cholesterol modified NIPAm oligomers on cancer targeting liposomes

    Li, Wengang

    2014-01-01

    Thermosensitive liposomes are a promising approach to controlled release and reduced drug cytotoxicity. Low molecular weight N-isopropylacrylamide (NIPAm) oligomers (NOs) with different architectures (main chain NOs (MCNOs) and side chain NOs (SCNOs)) were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and radical polymerization and then separately used to prepare thermosensitive liposomes. A more controlled and enhanced release was observed for both NO liposomes compared to pristine ones. Two release mechanisms depending on the oligomer architecture, namely "nail" for MCNOs and "comb" for SCNOs, are proposed. In addition to thermosensitivity, the cancer targeting property of NO liposomes was achieved by further biotinylation of the delivery system. © The Royal Society of Chemistry.

  8. Heat-induced formation of myosin oligomer-soluble filament complex in high-salt solution.

    Shimada, Masato; Takai, Eisuke; Ejima, Daisuke; Arakawa, Tsutomu; Shiraki, Kentaro

    2015-02-01

    Heat-induced aggregation of myosin into an elastic gel plays an important role in the water-holding capacity and texture of meat products. Here, we investigated thermal aggregation of porcine myosin in high-salt solution over a wide temperature range by dynamic light scattering experiments. The myosin samples were readily dissolved in 1.0 M NaCl at 25 °C followed by dilution into various salt concentrations. The diluted solutions consistently contained both myosin monomers and soluble filaments. The filament size decreased with increasing salt concentration and temperature. High temperatures above Tm led to at least partial dissociation of soluble filaments and thermal unfolding, resulting in the formation of soluble oligomers and binding to the persistently present soluble filaments. Such a complex formation between the oligomers and filaments has never been observed. Our results provide new insight into the heat-induced myosin gelation in high-salt solution. PMID:25445683

  9. Characterization of oligomers from methylglyoxal under dark conditions: a pathway to produce secondary organic aerosol through cloud processing during nighttime

    F. Yasmeen; N. Sauret; Gal, J.-F.; Maria, P.-C.; Massi, L.; W. Maenhaut; Claeys, M.

    2010-01-01

    Aqueous-phase oligomer formation from methylglyoxal, a major atmospheric photooxidation product, has been investigated in a simulated cloud matrix under dark conditions. The aim of this study was to explore an additional pathway producing secondary organic aerosol (SOA) through cloud processes without participation of photochemistry during nighttime. Indeed, atmospheric models still underestimate SOA formation, as field measurements have revealed more SOA than predicted. Soluble oligomers (&l...

  10. Single-site modifications and their effect on the folding stability of m-phenylene ethynylene oligomers.

    Goto, Hirofumi; Heemstra, Jennifer M; Hill, David J; Moore, Jeffrey S

    2004-03-18

    [reaction: see text] The folded structure of a m-phenylene ethynylene oligomer is tolerant to single-site modifications to both the backbone sequence and end groups. The helical structure is reinforced by multiple noncovalent interactions, allowing the oligomer sequence to be customized without a significant change in stability in most cases. The small changes that are observed are consistent with the expected behavior of pi-stacked systems and demonstrate subtle control over folding through single-site modifications. PMID:15012057

  11. Unambiguous identification of esters as oligomers in secondary organic aerosol formed from cyclohexene and cyclohexene/α-pinene ozonolysis

    MÜller, L.; Reinnig, M.-C.; Warnke, J.; Hoffmann, Th.

    2007-01-01

    The build-up of oligomeric compounds during secondary organic aerosol (SOA) formation is subject of atmospheric research since several years. New particle formation and especially the SOA mass yield might be influenced significantly by oligomer formation. However, the chemical nature of observed oligomers and their formation pathways are still unclear. In this paper, the structural characterization of certain dimeric compounds (esters) formed during the ozonolysis of cyclohexene and cyclohexe...

  12. Quarternization of 3-azido-1-propyne oligomers obtained by copper(I)-catalyzed azide–alkyne cycloaddition polymerization

    Shun Nakano; Akihito Hashidzume; Takahiro Sato

    2015-01-01

    3-Azido-1-propyne oligomer (oligoAP) samples, prepared by copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) polymerization, were quarternized quantitatively with methyl iodide in sulfolane at 60 °C to obtain soluble oligomers. The conformation of the quarternized oligoAP in dilute DMSO-d6 solution was examined by pulse-field-gradient spin-echo NMR based on the touched bead model.

  13. Novel Novolac-Phthalonitrile and Siloxane-Phthalonitrile Resins cured with low melting Novolac Oligomers for Flame Retardant Structural Thermosets

    Hardrict, Shauntrece Nicole

    2003-01-01

    Novel Novolac-Phthalonitrile and Siloxane-Phthalonitrile Resins cured with low melting Novolac Oligomers for Flame Retardant Structural Thermosets Shauntrece Nicole Hardrict Department of Chemistry Virginia Polytechnic Institute and State University ABSTRACT The chemical modification of low molecular weight novolac oligomers and siloxane/silane-containing monomers has led to novel phthalonitrile derivatives with low glass transition temperatures, ranging from -25 to 75 ºC...

  14. Disrupting self-assembly and toxicity of amyloidogenic protein oligomers by "molecular tweezers" - from the test tube to animal models

    Attar, A.; Bitan, G.

    2014-01-01

    Despite decades of research, therapy for diseases caused by abnormal protein folding and aggregation (amyloidoses) is limited to treatment of symptoms and provides only temporary and moderate relief to sufferers. The failure in developing successful diseasemodifying drugs for amyloidoses stems from the nature of the targets for such drugs - primarily oligomers of amyloidogenic proteins, which are distinct from traditional targets, such as enzymes or receptors. The oligomers are metastable, do...

  15. Estimating the energy of intramolecular hydrogen bonds in chitosan oligomers

    Mikhailov, G. P.; Lazarev, V. V.

    2016-07-01

    The effect the number of chitosan monomer units CTS n ( n = 1-5), the protonation of chitosan dimers, and the interaction between CTS n ( n = 1-3) and acetate ions have on the energy of intramolecular hydrogen bonds is investigated by means of QTAIM analysis and solving the vibrational problem within the cluster-continuum model. It is established that the number of H-bonds in CTS n is 2 n - 1 and the total energy of H-bonds grows by ~20 kJ/mol. It is concluded that the hydrogen bonds between CTS and acetate ions play a major role in the stabilization of polyelectrolyte complexes in dilute acetic acid solutions of CTS.

  16. Simulation of tethered oligomers in nanochannels using multi-particle collision dynamics

    Raghu, Riyad; Schofield, Jeremy

    2012-01-01

    The effect of a high Reynold's number, pressure-driven flow of a compressible gas on the conformation of an oligomer tethered to the wall of a square-channel is studied under both ideal solvent and poor solvent conditions using a hybrid multiparticle collision dynamics and molecular dynamics algorithm. Unlike previous studies, the flow field contains an elongational component in addition to a shear component as well as fluid slip near the walls and results in a Schmidt number for the polymer ...

  17. PFO-BPy Solubilizers for SWNTs: Modelling of Polymers from Oligomers

    Glanzmann, Livia N.; Mowbray, Duncan J.; Rubio, Angel

    2014-01-01

    Due to their exeptional physical properties, single walled carbon nanotubes (SWNTs) embedded in organic polymers (polymer-SWNT hybrid systems) are promising materials for organic photovoltaic (OPV) devices. Already at the SWNT sorting and debundling step, polymers such as the copolymer of 9,9-dioctylfluorenyl-2,7-diyl and bipyridine (PFO-BPy) are used as solubilizers. However, to model polymer-SWNT hybrid systems, we must first determine the smallest oligomer needed to sufficiently describe t...

  18. Interchain tube pressure effect in extensional flows of oligomer diluted nearly monodisperse polystyrene melts

    Rasmussen, Henrik K.; Huang, Qian

    2014-01-01

    times and entanglements have been established based on published extensional experiments on nearly monodisperse polystyrene melts. The constitutive equation has shown agreement with the experimental startup of and steady extension data from Huang et al. (Macromolecules 46:5026–5035, 2013a) based on 285...... and 545 kg/mol polystyrenes diluted in styrene oligomers containing 3.3 (1.92 kg/mol) and 7.3 (4.29 kg/mol) Kuhn steps....

  19. Luminescent Quadrupolar Borazine Oligomers: Synthesis, Photophysics, and Two-Photon Absorption Properties.

    Chen, Pangkuan; Marshall, Ariel S; Chi, San-Hui; Yin, Xiaodong; Perry, Joseph W; Jäkle, Frieder

    2015-12-01

    A set of monodisperse bent donor-acceptor-donor-type conjugated borazine oligomers, BnNn+1 (n=1-4), incorporating electron-rich triarylamine donor and electron-deficient triarylborane acceptor units has been prepared through an iterative synthetic approach that takes advantage of highly selective silicon-boron and tin-boron exchange reactions. The effect of chain elongation on the electrochemical, one- and two-photon properties and excited-state photodynamics has been investigated. Strong intramolecular charge transfer (ICT) from the arylamine donors to boryl-centered acceptor sites results in emissions with high quantum yields (Φfl >0.5) in the range of 400-500 nm. Solvatochromic effects lead to solvent shifts as large as ∼70 nm for the shortest member (n=1) and gradually decrease with chain elongation. The oligomers exhibit strong two-photon absorption (2PA) in the visible spectral region with 2PA cross sections as large as 1410 GM (n=4), and broadband excited-state absorption (ESA) attributed to long-lived singlet-singlet and radical cation/anion absorption. The excited-state dynamics also show sensitivity to the solvent environment. Electrochemical observations and DFT calculations (B3LYP/6-31G*) reveal spatially separated HOMO and LUMO levels resulting in highly fluorescent oligomers with strong ICT character. The BnNn+1 oligomers have been used to demonstrate the detection of cyanide anions with association constants of log K>7. PMID:26514664

  20. Antiviral Effects of Antisense Morpholino Oligomers in Murine Coronavirus Infection Models▿

    Burrer, Renaud; Neuman, Benjamin W.; Ting, Joey P.C.; Stein, David A.; Moulton, Hong M.; Iversen, Patrick L.; Kuhn, Peter; Michael J Buchmeier

    2007-01-01

    The recent emergence of novel pathogenic human and animal coronaviruses has highlighted the need for antiviral therapies that are effective against a spectrum of these viruses. We have used several strains of murine hepatitis virus (MHV) in cell culture and in vivo in mouse models to investigate the antiviral characteristics of peptide-conjugated antisense phosphorodiamidate morpholino oligomers (P-PMOs). Ten P-PMOs directed against various target sites in the viral genome were tested in cell...

  1. Polyethylenimine-modified Pluronics (PCMs) Improve Morpholino Oligomer Delivery in Cell Culture and Dystrophic mdx Mice

    Wang, Mingxing; Wu, Bo; Lu, Peijuan; Cloer, Caryn; Tucker, Jay D; Lu, Qilong

    2012-01-01

    We investigated a series of small-sized polyethylenimine (PEI, 0.8/1.2 k)-conjugated pluronic copolymers (PCMs) for their potential to enhance delivery of an antisense phosphorodiamidate morpholino oligomer (PMO) in vitro and in dystrophic mdx mice. PCM polymers containing pluronics of molecular weight (Mw) ranging 2–6 k, with hydrophilic-lipophilic balance (HLB) 7–23, significantly enhanced PMO-induced exon-skipping in a green fluorescent protein (GFP) reporter-based myoblast culture system....

  2. Differential effects of co-chaperonin homologs on cpn60 oligomers.

    Bonshtien, Anat L; Parnas, Avital; Sharkia, Rajach; Niv, Adina; Mizrahi, Itzhak; Azem, Abdussalam; Weiss, Celeste

    2009-09-01

    In this study, we have investigated the relationship between chaperonin/co-chaperonin binding, ATP hydrolysis, and protein refolding in heterologous chaperonin systems from bacteria, chloroplast, and mitochondria. We characterized two types of chloroplast cpn60 oligomers, ch-cpn60 composed of alpha and beta subunits (alpha(7)beta(7) ch-cpn60) and one composed of all beta subunits (beta(14) ch-cpn60). In terms of ATPase activity, the rate of ATP hydrolysis increased with protein concentration up to 60 microM, reflecting a concentration at which the oligomers are stable. At high concentrations of cpn60, all cpn10 homologs inhibited ATPase activity of alpha(7)beta(7) ch-cpn60. In contrast, ATPase of beta(14) ch-cpn60 was inhibited only by mitochondrial cpn10, supporting previous reports showing that beta(14) is functional only with mitochondrial cpn10 and not with other cpn10 homologs. Surprisingly, direct binding assays showed that both ch-cpn60 oligomer types bind to bacterial, mitochondrial, and chloroplast cpn10 homologs with an equal apparent affinity. Moreover, mitochondrial cpn60 binds chloroplast cpn20 with which it is not able to refold denatured proteins. Protein refolding experiments showed that in such instances, the bound protein is released in a conformation that is not able to refold. The presence of glycerol, or subsequent addition of mitochondrial cpn10, allows us to recover enzymatic activity of the substrate protein. Thus, in our systems, the formation of co-chaperonin/chaperonin complexes does not necessarily lead to protein folding. By using heterologous oligomer systems, we are able to separate the functions of binding and refolding in order to better understand the chaperonin mechanism. PMID:19224397

  3. High-Capacity Conductive Nanocellulose Paper Sheets for Electrochemically Controlled Extraction of DNA Oligomers

    Aamir Razaq; Gustav Nyström; Maria Strømme; Albert Mihranyan; Leif Nyholm

    2011-01-01

    Highly porous polypyrrole (PPy)-nanocellulose paper sheets have been evaluated as inexpensive and disposable electrochemically controlled three-dimensional solid phase extraction materials. The composites, which had a total anion exchange capacity of about 1.1 mol kg(-1), were used for extraction and subsequent release of negatively charged fluorophore tagged DNA oligomers via galvanostatic oxidation and reduction of a 30-50 nm conformal PPy layer on the cellulose substrate. The ion exchange ...

  4. Complexation between scandium and nitrogen-containing para-alkylphenol formaldehyde oligomer

    Stoichiometric composition and bond nature in scandium complex with nitrogen-containing p-alkylphenol-formaldehyde oligomer (NAFO) formed upon scandium extraction by NAFO solution in toluene from chloride aqueous solutions are determined by the interphase distribution method, IR and UV spectroscopy. It is found that scandium coordination in the complex corresponds to a distorted octahedron. Conformation feasibilities of scandium complexing with NAFO are examined

  5. Constituent models and large transverse momentum reactions

    The discussion of constituent models and large transverse momentum reactions includes the structure of hard scattering models, dimensional counting rules for large transverse momentum reactions, dimensional counting and exclusive processes, the deuteron form factor, applications to inclusive reactions, predictions for meson and photon beams, the charge-cubed test for the e/sup +-/p → e/sup +-/γX asymmetry, the quasi-elastic peak in inclusive hadronic reactions, correlations, and the multiplicity bump at large transverse momentum. Also covered are the partition method for bound state calculations, proofs of dimensional counting, minimal neutralization and quark--quark scattering, the development of the constituent interchange model, and the A dependence of high transverse momentum reactions

  6. Chemical Constituents from Roots of Flemingia philippinensis

    FU Man-qin; DENG Dun; FENG Shi-xiu; HUANG Ri-ming; TIAN Shuai; QIU Sheng-xiang

    2012-01-01

    Objective To study the chemical constituents from the roots of Flemingia philippinensis.Methods The chemical constituents were isolated and purified by combination of silica gel column,Sephadex LH-20,polyamide,and ODS column chromatography.The structures of the isolated compounds were identified by means of spectral data.Results Ten compounds were isolated from F.philippinensis and identified as isoderrone (1),dalparvin A (2),prunetin (3),7,3'-dihydroxy-5,4',5'-trimethoxyisoflavone (4),pratensein-7-O-β-D-glucoside (5),sissotrin (6),sophororicoside (7),formononetin (8),orobol (9),and biochanin A (10).Conclusion Compounds 1-6 are obtained from this plant for the first time.

  7. [Chemical constituents in higher polar substances from Desmodium caudatum].

    Zhu, Dan; Wang, Di; Wang, Guang-Hui; Guo, Zhi-Jian; Zou, Xiu-Hong; Lin, Ting; Chen, Hai-Feng

    2014-08-01

    In this study the chemical constituents of the higher polar sustances from Desmodium caudatum were investigated.The compounds were isolated by using column chromatographies over silicagel, polyamide, ODS, Sephadex LH-20, and preparative HPLC. The structures of these compounds were identified on the basis of NMR and MS spectra. Thirteen compounds were obtained and their structures were identified as vanillin(1), loliolide(2), indole-3-carboxaldehyde(3), salicylic acid(4), swertisin(5), saccharumoside C(6), isosinensin (7), kaempferol 3-O-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside (8), isovitexin (9), vitexin (10), nothofagin(11), resveratroloside (12), and 2"-α-rhamnopyranosyl-7-O-methylvitexin (13). Except for compound 5, the remaining compounds were isolated from D. caudatum for the first time. Compounds 2, 3, 6-8, 11-13 were separated from the genus Desmodium for the first time. PMID:25509297

  8. Phytochemical constituents of some Indian medicinal plants.

    Dhandapani, R; Sabna, B

    2008-04-01

    Alkaloids, tannins, saponins, steroid, terpenoid, flavonoids, phlobatannin and cardie glycoside distribution in seven medicinal plants belonging to different families were assessed and compared. The medicinal plants investigated were Aegle marmelos, Cynodon dactylon, Eclipta prostrata, Moringa pterygosperma, Pongamia pinnata, Sida acuta and Tridax procumbens. The significance of the plants in traditional medicine and the importance of the distribution of these chemical constituents were discussed with respect to the role of these plants in ethnomedicine in India. PMID:22557280

  9. Model for quark and lepton constituents

    Fairlie, D.; Nuyts, J.; Taormina, A.

    1983-01-01

    A model of subconstituents for quarks and leptons is presented in which each of three different types transforms under a different group which is gauged. The binding is taken as magnetic, the dual of the usual electric charge and hence very strong. The spin of the constituents is zero. The spin of the bound states arises dynamically. Weak interactions violate parity maximally and the Weinberg angle, related to the generation problem, comes out well numerically. Two exotic states are predicted.

  10. Model for quark and lepton constituents

    Fairlie, D.; Nuyts, J.; Taormina, A.

    1983-01-01

    A model of subconstituents for quarks and leptons is presented in which each of three different types transforms under a different group which is gauged. The binding is taken as magnetic, the dual of the usual electric charge, and hence very strong. The spin of the constituents is zero. The spin of the bound states arises dynamically. Weak interactions violate parity maximally and the Weinberg angle, related to the generation problem, comes out well numerically. Two exotic states are predicted.

  11. POSITIVE COMMUNICATION: DEFINITION AND CONSTITUENT FEATURES

    Leontovich Olga Arkadyevna

    2014-01-01

    Whereas positive communication is generally seen as an appealing phenomenon of interaction, it remains under-researched from the theoretical point of view. The topic warrants special attention because in today's Russian world negativity prevails, which is due to opposing political views, incompatible values in public discourse. The paper aims at the study of the constituent characteristics, structural components and basic mechanisms of positive communication. The analysis of the dictionary de...

  12. Effect of phenolic oligomer on adhesion of poly (ethylene terephthalate) film laminated steel sheets by Electron Beam Curing method

    Adhesion of poly (ethylene terephthalate) film by Electron Beam Curing (EBC) method which can be thought as an energy-saving process was studied for the purpose of bestowing economically design and distinctness of image on thermosetting high molecular weight polyester precoated steel sheets. Adhesion of EB curable resins onto metal is generally poor. In this report, addition of EB curable phenolic resole oligomer with bifunctional acrylates to the top coat used for precoated steel was studied in order to increase the adhesion of an EB curable adhesive, and it was found that the phenolic oligomer is tremendously effective for the improvement of adhesion. The reasons why the phenolic oligomer provides excellent adhesion were 1) elongation at break of the top coat to which the phenolic oligomer is added is little decreased by EB irradiation, and the formability does not reduce. 2) As the phenolic oligomer is unevenly distributed to the surface layer of the top coat, it is suggested that the contact frequency of the phenolic oligomer to the EB curable adhesive is so high that graft polymerization between them is liable to occur. (author)

  13. Crystallization and preliminary crystallographic study of oligomers of the haemolytic lectin CEL-III from the sea cucumber Cucumaria echinata

    Oligomers of the haemolytic lectin CEL-III from the marine invertebrate C. echinata were crystallized and data were collected to 3.3 Å resolution using synchrotron radiation. CEL-III is a Ca2+-dependent haemolytic lectin isolated from the marine invertebrate Cucumaria echinata. This lectin binds to Gal/GalNAc-containing carbohydrate chains on the cell surface and, after conformational changes, oligomerizes to form ion-permeable pores in cell membranes. CEL-III also forms soluble oligomers similar to those formed in cell membranes upon binding of specific carbohydrates in high-pH and high-salt solutions. These soluble and membrane CEL-III oligomers were crystallized and X-ray diffraction data were collected. Crystals of soluble oligomers and membrane oligomers diffracted X-rays to 3.3 and 4.2 Å resolution, respectively, using synchrotron radiation and the former was found to belong to space group C2. Self-rotation functional analysis of the soluble oligomer crystal suggested that it might be composed of heptameric CEL-III

  14. Multifunctional oligomer incorporation: a potent strategy to enhance the transfection activity of poly(l-lysine).

    Liu, Shuai; Yang, Jixiang; Ren, Hongqi; O'Keeffe-Ahern, Jonathan; Zhou, Dezhong; Zhou, Hao; Chen, Jiatong; Guo, Tianying

    2016-03-01

    Natural polycations, such as poly(l-lysine) (PLL) and chitosan (CS), have inherent superiority as non-viral vectors due to their unparalleled biocompatibility and biodegradability. However, the application was constrained by poor transfection efficiency and safety concerns. Since previous modification strategies greatly weakened the inherent advantages of natural polycations, developing a strategy for functional group introduction with broad applicability to enhance the transfection efficiency of natural polycations without compromising their cationic properties is imperative. Herein, two uncharged functional diblock oligomers P(DMAEL-b-NIPAM) and P(DMAEL-b-Vlm) were prepared from a lactose derivative, N-iso-propyl acrylamide (NIPAM) as well as 1-vinylimidazole (Vlm) and further functionalized with four small ligands folate, glutathione, cysteine and arginine, respectively, aiming to enhance the interactions of complexes with cells, which were quantified utilizing a quartz crystal microbalance (QCM) biosensor, circumventing the tedious material screening process of cell transfection. Upon incorporation with PLL and DNA, the multifunctional oligomers endow the formulated ternary complexes with great properties suitable for transfection, such as anti-aggregation in serum, destabilized endosome membrane, numerous functional sites for promoted endocytosis and therefore robust transfection activity. Furthermore, different from the conventional strategy of decreasing cytotoxicity by reducing the charge density, the multifunctional oligomer incorporation strategy maintains the highly positive charge density, which is essential for efficient cellular uptake. This system develops a new platform to modify natural polycations towards clinical gene therapy. PMID:26797493

  15. Simulation of tethered oligomers in nanochannels using multi-particle collision dynamics.

    Raghu, Riyad Chetram; Schofield, Jeremy

    2012-07-01

    The effect of a high Reynold's number, pressure-driven flow of a compressible gas on the conformation of an oligomer tethered to the wall of a square channel is studied under both ideal solvent and poor solvent conditions using a hybrid multiparticle collision dynamics and molecular dynamics algorithm. Unlike previous studies, the flow field contains an elongational component in addition to a shear component as well as fluid slip near the walls and results in a Schmidt number for the polymer beads that is less than unity. In both solvent regimes the oligomer is found to extend in the direction of flow. Under the ideal solvent conditions, torsional twisting of the chain and aperiodic cyclical dynamics are observed for the end of the oligomer. Under poor solvent conditions, a metastable helix forms in the end of the chain despite the lack of any attractive potential between beads in the oligomeric chain. The formation of the helix is postulated to be the result of a solvent induced chain collapse that has been confined to a single dimension by a strong flow field. PMID:22779677

  16. NEXAFS characterization of DNA components and molecular-orientation of surface-bound DNA oligomers

    Samuel, Newton T. [National ESCA and Surface Analysis Center for Biomedical Problems, Department of Chemical Engineering, University of Washington, Box 351750, Seattle, WA 98195 (United States); Lee, C.-Y. [National ESCA and Surface Analysis Center for Biomedical Problems, Department of Chemical Engineering, University of Washington, Box 351750, Seattle, WA 98195 (United States); Gamble, Lara J. [National ESCA and Surface Analysis Center for Biomedical Problems, Department of Bioengineering, University of Washington, Box 351750, Seattle, WA 98195 (United States); Fischer, Daniel A. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Castner, David G. [National ESCA and Surface Analysis Center for Biomedical Problems, Department of Chemical Engineering, University of Washington, Box 351750, Seattle, WA 98195 (United States) and National ESCA and Surface Analysis Center for Biomedical Problems, Department of Bioengineering, University of Washington, Box 351750, Seattle, WA 98195 (United States)]. E-mail: castner@nb.engr.washington.edu

    2006-07-15

    Single stranded DNA oligomers (ssDNA) immobilized onto solid surfaces forms the basis for several biotechnological applications such as DNA microarrays, affinity separations, and biosensors. Surface structure of Surface-bound oligomers is expected to significantly influence their biological activity and interactions with the environment. In this study near-edge X-ray absorption fine structure spectroscopy (NEXAFS) is used to characterize the components of DNA (nucleobases, nucleotides and nucleosides) and the orientation information of surface-bound ssDNA. The K-edges of carbon, nitrogen and oxygen have spectra with features that are characteristic of the different chemical species present in the nucleobases of DNA. The effect of addition of the DNA sugar and phosphate components on the NEXAFS K-edge spectra was also investigated. The polarization-dependent nitrogen K-edge NEXAFS data show significant changes for different orientations of surface bound ssDNA. These results establish NEXAFS as a powerful technique for chemical and structural characterization of surface-bound DNA oligomers.

  17. Enzymatic generation of galactose-rich oligosaccharides/oligomers from potato rhamnogalacturonan I pectic polysaccharides.

    Khodaei, Nastaran; Karboune, Salwa

    2016-04-15

    Potato pulp by-product rich in galactan-rich rhamnogalacturonan I (RG I) was investigated as a new source of oligosaccharides with potential prebiotic properties. The efficiency of selected monocomponent enzymes and multi-enzymatic preparations to generate oligosaccharides/oligomers from potato RG I was evaluated. These overall results of yield were dependent on the activity profile of the multi-enzymatic preparations. Highest oligo-RG I yield of 93.9% was achieved using multi-enzymatic preparation (Depol 670L) with higher hydrolytic activity toward side chains of RG I as compared to its backbone. Main oligo-RG I products were oligosaccharides with DP of 2-12 (79.8-100%), while the oligomers with DP of 13-70 comprised smaller proportion (0.0-20.2%). Galactose (58.9-91.2%, w/w) was the main monosaccharide of oligo-RG I, while arabinose represented 0.0-12.1%. An understanding of the relationship between the activity profile of multi-enzymatic preparations and the yield/DP of oligo-RG I was achieved. This is expected to provide the capability to generate galacto- and galacto(arabino) oligosaccharides and their corresponding oligomers from an abundant by-product. PMID:26616968

  18. Structural Properties of HIV Integrase. Lens Epithelium-derived Growth Factor Oligomers

    Gupta, K.; Diamond, T; Hwang, Y; Bushman, F; Van Duyne, G

    2010-01-01

    Integrase (IN) is the catalytic component of the preintegration complex, a large nucleoprotein assembly critical for the integration of the retroviral genome into a host chromosome. Although partial crystal structures of human immunodeficiency virus IN alone and its complex with the integrase binding domain of the host factor PSIP1/lens epithelium-derived growth factor (LEDGF)/p75 are available, many questions remain regarding the properties and structures of LEDGF-bound IN oligomers. Using analytical ultracentrifugation, multiangle light scattering, and small angle x-ray scattering, we have established the oligomeric state, stoichiometry, and molecular shapes of IN {center_dot} LEDGF complexes in solution. Analyses of intact IN tetramers bound to two different LEDGF truncations allow for placement of the integrase binding domain by difference analysis. Modeling of the small angle x-ray scattering envelopes using existing structural data suggests domain arrangements in the IN oligomers that support and extend existing biochemical data for IN {center_dot} LEDGF complexes and lend new insights into the quaternary structure of LEDGF-bound IN tetramers. These IN oligomers may be involved in stages of the viral life cycle other than integration, including assembly, budding, and early replication.

  19. NEXAFS characterization of DNA components and molecular-orientation of surface-bound DNA oligomers

    Single stranded DNA oligomers (ssDNA) immobilized onto solid surfaces forms the basis for several biotechnological applications such as DNA microarrays, affinity separations, and biosensors. Surface structure of Surface-bound oligomers is expected to significantly influence their biological activity and interactions with the environment. In this study near-edge X-ray absorption fine structure spectroscopy (NEXAFS) is used to characterize the components of DNA (nucleobases, nucleotides and nucleosides) and the orientation information of surface-bound ssDNA. The K-edges of carbon, nitrogen and oxygen have spectra with features that are characteristic of the different chemical species present in the nucleobases of DNA. The effect of addition of the DNA sugar and phosphate components on the NEXAFS K-edge spectra was also investigated. The polarization-dependent nitrogen K-edge NEXAFS data show significant changes for different orientations of surface bound ssDNA. These results establish NEXAFS as a powerful technique for chemical and structural characterization of surface-bound DNA oligomers

  20. NMR studies of DNA oligomers and their interactions with minor groove binding ligands

    Fagan, P A [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1996-05-01

    The cationic peptide ligands distamycin and netropsin bind noncovalently to the minor groove of DNA. The binding site, orientation, stoichiometry, and qualitative affinity of distamycin binding to several short DNA oligomers were investigated by NMR spectroscopy. The oligomers studied contain A,T-rich or I,C-rich binding sites, where I = 2-desaminodeoxyguanosine. I{center_dot}C base pairs are functional analogs of A{center_dot}T base pairs in the minor groove. The different behaviors exhibited by distamycin and netropsin binding to various DNA sequences suggested that these ligands are sensitive probes of DNA structure. For sites of five or more base pairs, distamycin can form 1:1 or 2:1 ligand:DNA complexes. Cooperativity in distamycin binding is low in sites such as AAAAA which has narrow minor grooves, and is higher in sites with wider minor grooves such as ATATAT. The distamycin binding and base pair opening lifetimes of I,C-containing DNA oligomers suggest that the I,C minor groove is structurally different from the A,T minor groove. Molecules which direct chemistry to a specific DNA sequence could be used as antiviral compounds, diagnostic probes, or molecular biology tools. The author studied two ligands in which reactive groups were tethered to a distamycin to increase the sequence specificity of the reactive agent.

  1. Dynamics in coarse-grained models for oligomer-grafted silica nanoparticles

    Hong, Bingbing

    2012-01-01

    Coarse-grained models of poly(ethylene oxide) oligomer-grafted nanoparticles are established by matching their structural distribution functions to atomistic simulation data. Coarse-grained force fields for bulk oligomer chains show excellent transferability with respect to chain lengths and temperature, but structure and dynamics of grafted nanoparticle systems exhibit a strong dependence on the core-core interactions. This leads to poor transferability of the core potential to conditions different from the state point at which the potential was optimized. Remarkably, coarse graining of grafted nanoparticles can either accelerate or slowdown the core motions, depending on the length of the grafted chains. This stands in sharp contrast to linear polymer systems, for which coarse graining always accelerates the dynamics. Diffusivity data suggest that the grafting topology is one cause of slower motions of the cores for short-chain oligomer-grafted nanoparticles; an estimation based on transition-state theory shows the coarse-grained core-core potential also has a slowing-down effect on the nanoparticle organic hybrid materials motions; both effects diminish as grafted chains become longer. © 2012 American Institute of Physics.

  2. LptA Assembles into Rod-Like Oligomers Involving Disorder-to-Order Transitions

    Santambrogio, Carlo; Sperandeo, Paola; Villa, Riccardo; Sobott, Frank; Polissi, Alessandra; Grandori, Rita

    2013-10-01

    LptA is a periplasmic protein involved in the transport of lipopolysaccharide (LPS) from the inner membrane (IM) to the outer membrane (OM) of Gram-negative bacteria. Growing evidence supports a model in which LptA assembles into oligomers, forming a physical bridge connecting IM and OM. This work investigates assembly and architecture of LptA oligomers. Circular dichroism and "native" electrospray-ionization ion-mobility mass spectrometry (ESI-IM-MS) are employed to test concentration dependence of LptA structural features and to analyze the morphology of higher-order aggregates. The results show that LptA progressively assembles into rod-like oligomers without fixed stoichiometry, and grows by an n + 1 mechanism up to at least the pentamer. The oligomerization process induces disorder-to-order transitions in the polypeptide chain. Comparison with crystallographic and computational data suggests that these conformational changes likely involve short disordered regions at the N- and C-termini of monomeric LptA. The protein response to thermal denaturation displays strong concentration dependence, indicating that oligomerization increases protein stability. LptA conformational stability can also be enhanced by in vitro LPS binding. The genesis of these fibrillar structures could be relevant for the correct transport of LPS across the bacterial periplasm.

  3. Panchromatic Light Capture and Efficient Excitation Transfer Leading to Near-IR Emission of BODIPY Oligomers.

    Sharma, Ritambhara; Gobeze, Habtom B; D'Souza, Francis; Ravikanth, Mangalampalli

    2016-08-18

    All-BODIPY-based (BODIPY=boron-dipyrromethene) donor-acceptor systems capable of wide-band absorbance leading to efficient energy transfer in the near-IR region are reported. A covalently linked 3-pyrrolyl BODIPY-BODIPY dimer building block bearing an ethynyl group at the meso-aryl position is synthesized and coupled with three different monomeric BODIPY/pyrrolyl BODIPY building blocks with a bromo/iodo group under Pd(0) coupling conditions to obtain three covalently linked 3-pyrrolyl-BODIPY-based donor-acceptor oligomers in 19-29 % yield. The oligomers are characterized in detail by 1D and 2D NMR spectroscopy, high-resolution mass spectrometry, and optical spectroscopy. Due to the presence of different functionalized BODIPY derivatives in the oligomers, panchromatic light capture (300-725 nm) is witnessed. Fluorescence studies reveal singlet-singlet energy transfer from BODIPY monomer to BODIPY dimer leading to emission in the 700-800 nm range. Theoretical modeling according to the Förster mechanism predicts ultrafast energy transfer due to good spectral overlap of the donor and acceptor entities. Femtosecond transient absorption studies confirm this to be the case and thus show the relevance of the currently developed all-BODIPY-based energy-funneling supramolecular sytems with near-IR emission to solar-energy harvesting applications. PMID:27168532

  4. Detection of Aβ Monomers and Oligomers: Early Diagnosis of Alzheimer's Disease.

    Zhou, Yanli; Liu, Lantao; Hao, Yuanqiang; Xu, Maotian

    2016-03-18

    Alzheimer's disease (AD), as the most common progressive neurodegenerative disorder, is pathologically characterized by deposition of extracellular plaque composed of amyloid-β peptide (Aβ). Different assembled states of Aβ have been considered as both important biomarkers and drug targets for the diagnosis and therapy of AD. Recent studies demonstrate that small, diffusible Aβ oligomers formed by aggregation of Aβ monomers are the major toxic agents in AD. Therefore, the development of reliable assays for Aβ (both monomers and oligomers) will be important for the early differential diagnosis of dementia, predicting the progression of AD, as well as monitoring the effectiveness of novel anti-Aβ drugs for AD. In this review, we summarize the recent progress made in the development of techniques for detection of Aβ monomers and oligomers. In particular, the principles governing the design of these sensors are classified and summarized. Moreover, the advantages and disadvantages of the assays are evaluated. This review also discusses the improvements and challenges for application of these assays in the early diagnosis of AD. PMID:26994700

  5. Analysis of gamma irradiated pepper constituents, 2

    Black pepper, white pepper, frozen green pepper and real pink pepper (kept in vinegar) were analyzed by reversed phase IIPLC. The extraction method and HPLC conditions were same as the first report, that is, the extraction from pepper was performed by Automatic Air Hammer and the extracted samples were separated on a reversed phase C8 column with a concave gradient from 0.1% trifluoro aceticacid (TFA) in water to 75% acetonitrile - 0.1% TFA in water for 60 minutes and detected at 210 nm, 280 nm. The different constituents were observed clearly on chromatogram between black pepper and white pepper. The different constituents were observed between different producing white peppers, and as the result that the analyzed pepper was distinguished its producing district by HPLC chromatogram. In order to investigate of effect of lyophilization on white pepper extracts, lyophilized extraction was analyzed by this HPLC method. Some peaks were decreased by lyophilization. The effect of heat on white pepper constituents was examined. White pepper was heated by electronic oven and thermostat. When the former method was used, decreased peak number (peak height was lower than without heat treatment) was more than latter method. These subtle change was able to be recognized by these HPLC chromatograms. (author)

  6. Constituent Particle Clustering and Pitting Corrosion

    Harlow, D. Gary

    2012-08-01

    Corrosion is a primary degradation mechanism that affects the durability and integrity of structures made of aluminum alloys, and it is a concern for commercial transport and military aircraft. In aluminum alloys, corrosion results from local galvanic coupling between constituent particles and the metal matrix. Due to variability in particle sizes, spatial location, and chemical composition, to name a few critical variables, corrosion is a complex stochastic process. Severe pitting is caused by particle clusters that are located near the material surface, which, in turn, serve as nucleation sites for subsequent corrosion fatigue crack growth. These evolution processes are highly dependent on the spatial statistics of particles. The localized corrosion growth rate is primarily dependent on the galvanic process perpetuated by particle-to-particle interactions and electrochemical potentials. Frequently, severe pits are millimeters in length, and these pits have a dominant impact on the structural prognosis. To accommodate large sizes, a model for three-dimensional (3-D) constituent particle microstructure is proposed. To describe the constituent particle microstructure in three dimensions, the model employs a fusion of classic stereological techniques, spatial point pattern analyses, and qualitative observations. The methodology can be carried out using standard optical microscopy and image analysis techniques.

  7. Lipophilic Constituents of Rumex vesicarius L. and Rumex dentatus L.

    Mona A. Abou Elfotoh

    2013-09-01

    Full Text Available Rumex dentatus L. and Rumex vesicarius L., of the family Polygonaceae, are edible herbs growing wild in Egypt. Their lipoid constituents were examined by both liquid chromatography/mass spectrometry (LC/MS and by gas chromatography/mass spectrometry (GC/MS. Their essential oil compositions consisted mainly of thujene, limonene, fenchon, estragole, and anethole but at largely different concentration. Fatty acid compositions were similar among the two species and consisting of palmitic, oleic, linoleic and linolenic acids, with R. vesicarius containing much higher level of omega-3-fatty acids. Both of the crude lipid extracts of the two species showed strong antioxidant activity as a radical quenching agent against 2,2-diphenyl-1-picrylhydrazyl (DPPH systems. Antioxidant activities were mostly associated with the polar lipid fractions. High performance thin layer chromatography (HPTLC, both in the normal and reversed phase,as well as liquid chromatography/mass spectrometry (LC/MS in the positive and negative electrospray ionization (ESI, showed unique chemical profile for each species that can be useful for species identification and quality control of herbal drug formulations. R. vesicarius was characterized by abundances of flavonoids and R. dentatus was abundant in anthraquinones and chromones.

  8. Lipophilic Constituents of Rumex vesicarius L. and Rumex dentatus L.

    Abou Elfotoh, Mona A.; Shams, Khaled A.; Anthony, Kevin P.; Shahat, Abdelaaty A.; Ibrahim, Magda T.; Abdelhady, Nevein M.; Abdel Azim, Nahla S.; Hammouda, Faiza M.; El-Missiry, Mostafa M.; Saleh, Mahmoud A.

    2013-01-01

    Rumex dentatus L. and Rumex vesicarius L., of the family Polygonaceae, are edible herbs growing wild in Egypt. Their lipoid constituents were examined by both liquid chromatography/mass spectrometry (LC/MS) and by gas chromatography/mass spectrometry (GC/MS). Their essential oil compositions consisted mainly of thujene, limonene, fenchon, estragole, and anethole but at largely different concentration. Fatty acid compositions were similar among the two species and consisting of palmitic, oleic, linoleic and linolenic acids, with R. vesicarius containing much higher level of omega-3-fatty acids. Both of the crude lipid extracts of the two species showed strong antioxidant activity as a radical quenching agent against 2,2-diphenyl-1-picrylhydrazyl (DPPH) systems. Antioxidant activities were mostly associated with the polar lipid fractions. High performance thin layer chromatography (HPTLC), both in the normal and reversed phase, as well as liquid chromatography/mass spectrometry (LC/MS) in the positive and negative electrospray ionization (ESI), showed unique chemical profile for each species that can be useful for species identification and quality control of herbal drug formulations. R. vesicarius was characterized by abundances of flavonoids and R. dentatus was abundant in anthraquinones and chromones. PMID:26784344

  9. Estimating instream constituent loads using replicate synoptic sampling, Peru Creek, Colorado

    Runkel, Robert L.; Walton-Day, Katherine; Kimball, Briant A.; Verplanck, Philip L.; Nimick, David A.

    2013-01-01

    The synoptic mass balance approach is often used to evaluate constituent mass loading in streams affected by mine drainage. Spatial profiles of constituent mass load are used to identify sources of contamination and prioritize sites for remedial action. This paper presents a field scale study in which replicate synoptic sampling campaigns are used to quantify the aggregate uncertainty in constituent load that arises from (1) laboratory analyses of constituent and tracer concentrations, (2) field sampling error, and (3) temporal variation in concentration from diel constituent cycles and/or source variation. Consideration of these factors represents an advance in the application of the synoptic mass balance approach by placing error bars on estimates of constituent load and by allowing all sources of uncertainty to be quantified in aggregate; previous applications of the approach have provided only point estimates of constituent load and considered only a subset of the possible errors. Given estimates of aggregate uncertainty, site specific data and expert judgement may be used to qualitatively assess the contributions of individual factors to uncertainty. This assessment can be used to guide the collection of additional data to reduce uncertainty. Further, error bars provided by the replicate approach can aid the investigator in the interpretation of spatial loading profiles and the subsequent identification of constituent source areas within the watershed. The replicate sampling approach is applied to Peru Creek, a stream receiving acidic, metal-rich effluent from the Pennsylvania Mine. Other sources of acidity and metals within the study reach include a wetland area adjacent to the mine and tributary inflow from Cinnamon Gulch. Analysis of data collected under low-flow conditions indicates that concentrations of Al, Cd, Cu, Fe, Mn, Pb, and Zn in Peru Creek exceed aquatic life standards. Constituent loading within the study reach is dominated by effluent from the

  10. Constituents of the flowers of Punica granatum.

    Wang, Rufeng; Wei Wang; Wang, Liang; Liu, Ruining; Yi Ding; Du, Lijun

    2006-12-01

    A new polyphenol compound named pomegranatate (1), together with, ellagic acid, 3,3',4'-tri-O-methylellagic acid, ethyl brevifolincarboxylate, urolic and maslinic acids, and daucosterol were isolated from the ethanolic extract of the flowers of Punica granatum. The structure of compound 1 was determined by spectroscopic analysis. Maslinic acid exhibited antioxidant activity, evaluated by measurement of LDL susceptibility to oxidation. PMID:16887296

  11. Structure/Property Relationships of Poly(L-lactic Acid/Mesoporous Silica Nanocomposites

    Javier Gudiño-Rivera

    2013-01-01

    Full Text Available Biodegradable poly(L-lactic acid (PLLA/mesoporous silica nanocomposites were prepared by grafting L-lactic acid oligomer onto silanol groups at the surface of mesoporous silica (SBA-15. The infrared results showed that the lactic acid oligomer was grafted onto the mesoporous silica. Surface characterization of mesoporous silica proved that the grafted oligomer blocked the entry of nitrogen into the mesopores. Thermal analysis measurements showed evidence that, once mixed with PLLA, SBA-15 not only nucleated the PLLA but also increased the total amount of crystallinity. Neat PLLA and its nanocomposites crystallized in the same crystal habit and, as expected, PLLA had a defined periodicity compared with the nanocomposites. This was because the grafted macromolecules on silica tended to cover the lamellar crystalline order. The g-SBA-15 nanoparticles improved the tensile moduli, increasing also the tensile strength of the resultant nanocomposites. Overall, the silica concentration tended to form a brittle material.

  12. An extract of Tagetes lucida and its phenolic constituents as antioxidants.

    Aquino, Rita; Cáceres, Armando; Morelli, Silvana; Rastrelli, Luca

    2002-12-01

    Analysis of a methanolic extract of Tagetes lucida leaves has resulted in the isolation of a new flavonol glycoside, quercetagenin 3,4'-dimethyl ether 7-O-beta-D-glucopyranoside (1), two new phenolic acids, 3-(2-O-beta-D-glucopyranosyl-4-methoxyphenyl)propanoic acid (2) and its methylester (3), and known flavonols, aromatic acids, and 7-methoxycoumarin. Using the DPPH degrees test, the extract and some of its constituents showed a significant free-radical-scavenging effect in comparison to alpha-tocopherol and standard flavonols. PMID:12502312

  13. Pembuatan Kitosan Oligomer Melalui Metode Degradasi Oksidatif Dengan Penambahan H2o2 Dan Ultrasonic Bath Dan Pengaruhnya Terhadap Viskositas Dan Berat Molekul

    Julianti, Salmi

    2012-01-01

    A research about the preparation of chitosan oligomers with oxidative degradation method by H2O2 30% and ultrasonic bath and the influence on viscosity and molecular weight has been studied. Chitosan oligomers were obtained under degradation process by strong oxidizing H2O2 30% and ultrasonic bath. The chitosan oligomers that were obtained, then determined the value of intrinsic viscosity by using ostwald viscometry and the value of molecular weight by using Mark-Kuhn-Houwink equation. The r...

  14. A Monte Carlo approach for assessing the specificity of protein oligomers observed in nano-electrospray mass spectra

    Lane, Laura A.; Ruotolo, Brandon T.; Robinson, Carol V.; Favrin, Giorgio; Benesch, Justin L. P.

    2009-06-01

    Nano-electrospray mass spectrometry is an emerging approach for studying the architecture and dynamics of complex oligomeric proteins. The analysis of such species can, however, be hindered by [`]non-specific' protein-protein associations which arise as a result of the electrospray method. To understand the formation of specific versus non-specific protein oligomers detected by mass spectrometry we have developed a simple and rapid computational approach. This Monte Carlo algorithm characterizes the occupancy of protein species in the last offspring droplets created by the nano-electrospray process. As such it enables us to assess whether oligomers detected in mass spectra reflect solution populations, or instead are the result of associations during droplet fission and evaporation. We have trained and validated this method on three model protein complexes which are not known to form higher order oligomers, and one which has a tendency to self-associate in solution in a concentration dependent manner. We have then compared predictions of droplet occupancy to abundances obtained from mass spectra for the tetrameric amyloid-related protein transthyretin, which can cause cardiomyopathy and polyneuropathy in humans. Interestingly, when such comparisons were made for wild-type transthyretin we were able to observe a propensity for the protein to form specific oligomers larger than the tetramer. In contrast, the tendency for the leucine-55-proline variant to form such oligomers was considerably reduced. We contemplate the significance of these specific higher order wild-type oligomers, and absence of such species in the variant, on the pathway of amyloid formation in transthyretin. More generally this easy-to-implement computational approach promises to improve our ability to identify oligomers of biological significance within the mass spectra of heterogenous protein complexes.

  15. 唇形科益母草等7种植物果实化学成分分析及形态特征%Studies on Chemical Constituents and Morphological Characters of the Fruits of Seven Labiatae Plants

    林文群; 曾碧榕; 陈忠

    2003-01-01

    The chemical constituents and morphological characters of the fruits of seven Labiatae plants have been studied. The results showed that the contents of fatty oils in the fruits are abundant. The main constituents of unsaturated fatty acids are α-linolenic acid, linolic acid, oleic acid, and arachidonic acid. The main constituents of saturated fatty acids are palmitic acid and stearic acid. Although different kinds of fruit oils have different content of a specific unsaturated fatty acid, the content of total unsaturated fatty acids is more than 90% of fruit oils. The fruits also contain eighteen kinds of amino acids and some mineral elements. Due to high nutritional ingredients, there is potential prospect to explore and utilize them. Their morphological characters were also discussed.

  16. Nucleon structure functions from constituent quark

    Khorramian, Ali N.; Arash, Firooz

    1999-10-01

    We have used a constituent quarks model to describe the nucleon structure function, F2( χ, Q2), for a wide range of χ=[10 -6,1] and Q2 = [0.5, 5000] GeV2. We have found that although F2 rises as χ decreases, but there exists some χ0 ≤ 10 -4 - 10 -5, below which the rise of F2 subsides drastically and hence, exhibits an almost flat behavior, compatible with the latest results from HERA, at least for low Q2.

  17. Corporate Governance: The Role of Other Constituencies

    Reinhard H. Schmidt

    1997-01-01

    The paper discusses the role of various constituencies in the corporate governance of a corporation from the perspective of incomplete contracts. A strict shareholder value orientation in the sense of a rule that at any time firm decisions should be made strictly in the interest of the present shareholders would make it difficult for the firm to establish long-term relationships as the potential partners would have to fear that, at a later stage of the co-operation, the shareholders or a mana...

  18. Chemical Constituents from Bletilla ochracea Schltr.

    CAI Jin-yan; ZHAO Lin; ZHANG De-zhi

    2007-01-01

    To study the chemical constituents in Bletilla ochracea Schltr. , repeated column chromatographies and preparative TLC were used for the isolation of compounds, and spectroscopic techniques(NMR, IR, UV and MS) were used for their structural identification. Seven compounds, 2,7-bis(allyloxy)-5-methoxy-3-methyl-9, 10-dihydrophenanthrene(1), gastrodin(2), gastrodigenin(3), β-sitosterol(4), stigmasterol(5), 4-hydroxybenzaldehyde(6), and daucosterol(7) were obtained from the roots of B. ochracea Schltr. Compound 1 is structurally illustrated as a novel compound, and the others are isolated from the title plant for the first time.

  19. Chemical constituents of Breynia glauca leaves

    Butsarakham Supudompol

    2005-08-01

    Full Text Available From the leaves of Breynia glauca, eight compounds including friedelin (1, 3-oxo- 4,5-sitosterone (2, friedelan-3β-ol (3, β-sitosterol (4, kaempferol (5, arbutin (6, kaempferol-3-O-rutinoside (7 and quercetion-3-O-glucoside (8 were isolated. The presence of these compounds supports the traditional use of this plant as a detoxifying agent. In addition, all of these chemical constituents were tested for antiviral potential against herpes simplex virus types 1 and 2, but were found to be inactive at 50 μg/ml.

  20. Phenolic constituents in irradiated banana fruit tissues

    The ''Hom Tong'' banana fruits grown in Thailand irradiated at 10, 20, 30 and 40 Krad and stored at 170C were used for analyses. The total phenolic compounds observed in irradiated fruits were higher than non-irradiated ones after harvested and 7 days of storage. The total phenolic components in the pulp of banana fruits were decreased during ripening when stored from 7-35 days. However, the phenolic constituents become increased again after 21 days of storage at the doses of 20 and 40 Krad due to the infected fruits by the fungus during the fruits approached to over ripe

  1. Vanadium(5) sorption from weakly acid solutions

    Distribution of vanadium(5) between diluted solutions of sulfuric acid and macroporous polymer sorbent impregnated by a mixture of nitrogen-containing phenol-formaldehyde resol oligomer (R) and tributylphosphate has been studied. It has been ascertained that under the conditions mentioned vanadium transfers to solid phase as a mixture of chelates with stoichiometric ratio V:R = 1:1 and 2:1. During sorption by impregnated sorbent R capacity in terms of vanadium increases essentially as compared with solvent extraction

  2. Decaying hadrons within constituent-quark models

    Kleinhappel, Regina

    2012-01-01

    Within conventional constituent-quark models hadrons come out as stable bound states of the valence (anti)quarks. Thereby the resonance character of hadronic excitations is completely ignored. A more realistic description of hadron spectra can be achieved by including explicit mesonic degrees of freedom, which couple directly to the constituent quarks. We will present a coupled-channel formalism that describes such hybrid systems in a relativistically invariant way and allows for the decay of excited hadrons. The formalism is based on the point-form of relativistic quantum mechanics. If the confining forces between the (anti)quarks are described by instantaneous interactions it can be formally shown that the mass-eigenvalue problem for a system that consists of dynamical (anti)quarks and mesons reduces to a hadronic eigenvalue problem in which the eigenstates of the pure confinement problem (bare hadrons) are coupled via meson loops. The only point where the quark substructure enters are form factors at the m...

  3. ASSESSING UNIVERSITY RESEARCH PERFORMANCE WITH MULTIPLE CONSTITUENCIES

    Kuang-Liang Liu

    2012-12-01

    Full Text Available The research performance of the university is critical to the national competitiveness. Previous research has established that research performance is based on scholarly publishing. Several studies suggested that journal ranking is the important research quality indicator. However, unilateral measurement for the research performance will seriously corrode the development of university research work. Assessing university research performance with multiple constituencies is a better to enhance the university research. Although substantial studies have been performed on the critical factors that affect knowledge exploration in the university, those in knowledge exploitation are still lacking. With the multiple constituencies, a fully understanding of research performance can be gained. In the research model, knowledge exploration represents the academic research and knowledge exploitation represents the university–industry collaboration. Data collected from 124 university data in online database. The study shows that knowledge exploration and exploitation both are significant positive predictors of university competitiveness. University resources play important roles to affect both knowledge exploration and exploitation in the university. The study also shows that higher knowledge exploration will enhance knowledge exploitation. Implications for theory and practice and suggestions for future research are discussed.

  4. POSITIVE COMMUNICATION: DEFINITION AND CONSTITUENT FEATURES

    Leontovich Olga Arkadyevna

    2014-12-01

    Full Text Available Whereas positive communication is generally seen as an appealing phenomenon of interaction, it remains under-researched from the theoretical point of view. The topic warrants special attention because in today's Russian world negativity prevails, which is due to opposing political views, incompatible values in public discourse. The paper aims at the study of the constituent characteristics, structural components and basic mechanisms of positive communication. The analysis of the dictionary definitions of the term positive and its combinability in the National Corpus of the Russian Language, the British National Corpus, the Corpus of Contemporary American English allows to describe positive communication as an interaction based on positive attitude, aimed at mutual understanding and satisfying for all the parties involved. Positive communication is constructive, effective, supportive and coloured with good emotions; these characteristics can be regarded as its constituent features. The universal components of positive communication include: positive intentionality, initiative, adaptation to the interlocutor, empathic listening and social support. On the other hand, assertiveness is culturally specific: it is regarded as part and parcel of positive communication in the US, but is not seen as desirable in Russia and a number of other countries. The research will be continued in order to further identify the characteristics of positive communication, trace and test the validity of the theoretical claims and predictions on the basis of real-life situations.

  5. Constituent gluons and the static quark potential

    Greensite, Jeff; Szczepaniak, Adam P.

    2016-04-01

    We suggest that Hamiltonian matrix elements between physical states in QCD might be approximated, in Coulomb gauge, by "lattice-improved" tree diagrams; i.e. tree diagram contributions with dressed ghost, transverse gluon, and Coulomb propagators obtained from lattice simulations. Such matrix elements can be applied to a truncated-basis treatment of hadronic states which include constituent gluons. As an illustration, we apply this hybrid approach to the heavy quark potential, for quark-antiquark separations up to 2.4 fm. The Coulomb string tension in SU(3) gauge theory is about a factor of 4 times greater than the asymptotic string tension. In our approach we show that a single constituent gluon is in principle sufficient, up to 2.4 fm, to reduce this overshoot by the factor required. The static potential remains linear, although the precise value of the string tension depends on details of the Couloumb gauge ghost and gluon propagators in the infrared regime. In this connection we present new lattice results for the transverse gluon propagator in position space.

  6. Analysis of gamma irradiated pepper constituents, 5

    Gamma irradiated peppers (10 krad, 100 krad, 1 Mrad) were analyzed by HPLC. The extraction method and HPLC conditions were same as the first report, that is, the extraction from pepper was performed by Automatic Air Hammer and the extracted samples were separated on a reversed phase C8 column with a concave gradient from 0.1% trifluoro aceticacid (TFA) in water to 75% acetonitrile-0.1% TFA in water for 60 minutes and detected at 210 nm, 280 nm. It is difficult to compare with irradiated and unirradiated pepper constituents by their peak height or area. And the method of multi variant statistically analysis was introduced. The 'peak n area/peak n + 1 area' ratio was calculated by computer. Each peak area was accounted by integrator. The value of these ratio were called 'parameter'. Each chromatogram has 741 parameters calculated with 39 chromatographic peaks. And these parameters were abopted to the multi variant statiscally analysis. Comparison of constituents between irradiated pepper and unirradiated pepper was done by 741 parameters. The correlation of parameters between irradiated and unirradiated was investigated by use of computer. Some parameters of irradiated case were selected as which had no correlation with unirradiated case. That is to say these parameters were thought to be changed with gamma spectrum irradiation. By this method, Coumarin was identified as a changed component with gamma irradiation. (author)

  7. Chemical constituents and antihistamine activity of Bixa orellana leaf extract

    Yong Yoke Keong

    2013-02-01

    Full Text Available Abstract Background Bixa orellana L. has been traditionally used in Central and South America to treat a number of ailments, including internal inflammation, and in other tropical countries like Malaysia as treatment for gastric ulcers and stomach discomfort. The current study aimed to determine the major chemical constituents of the aqueous extract of B. orellana (AEBO and to evaluate the antihistamine activity of AEBO during acute inflammation induced in rats. Methods Acute inflammation was produced by subplantar injection of 0.1 mL of 0.1% histamine into the right hind paw of each rat in the control and treatment groups. The degree of edema was measured before injection and at the time points of 30, 60, 120, 180, 240 and 300 min after injection. Changes of peritoneal vascular permeability were studied using Evans blue dye as a detector. Vascular permeability was evaluated by the amount of dye leakage into the peritoneal cavity in rats. To evaluate the inhibitory effect of AEBO on biochemical mediators of vascular permeability, the levels of nitric oxide (NO and vascular endothelial growth factor (VEGF were determined in histamine-treated paw tissues. The major constituents of AEBO were determined by gas chromatography–mass spectrometry (GC-MS analysis. Results AEBO produced a significant inhibition of histamine-induced paw edema starting at 60 min time point, with maximal percentage of inhibition (60.25% achieved with a dose of 150 mg/kg of AEBO at 60 min time point. Up to 99% of increased peritoneal vascular permeability produced by histamine was successfully suppressed by AEBO. The expression of biochemical mediators of vascular permeability, NO and VEGF, was also found to be downregulated in the AEBO treated group. Gas chromatography–mass spectrometry (GC-MS analysis revealed that the major constituent in AEBO was acetic acid. Conclusions The experimental findings demonstrated that the anti-inflammatory activity of AEBO was

  8. Frying temperatures and minor constituents of oils and fats

    Boskou, Dimitrios

    1998-08-01

    Full Text Available Two important classes of minor constituents of oils and fats are tocopherols and sterols. Both these classes are biologically active and they also affect the stability and performance of an oil at elevated temperatures. Tocopherols are phenolic antioxidants that react with free radicals and their concentration is reduced signifantly when the oil is heated. α-TocopheroI is lost faster during deep-fat frying than the beta, gamma and delta homologues. In the presence of stronger antioxidants, natural or synthetic, losses of α-tocopherol can be eliminated. Unchanged phytosterols naturally present in vegetable oils are believed to be beneficial for the health. Depending on the chemical structure, phytosterols may act as prooxidants or antioxidants. Sterols with an ethylidene group in the side chain have been found effective in retarding polymerisation at temperatures similar to those of deep-fat frying. Under unfavourable conditions (high temperature, presence of air oxidation products are formed from sterols and a marked increase in the oxidation rate of the fat is observed. Oxidation products of the main phytosterols, β-sitosterol and stigmasterol, are: hydrocarbons (3,5-diene and 3,5,22-triene, mono-, di- and triunsaturated ketosteroids (4-en-3-one, 3,5-dien-7-one, 3,5,22-trien-7-one, 5,6-epoxy derivatives, 3,7-diols and pregnane derivatives. Other minor constituents which may affect the rate of degradation of unsaturated triacylglycerols at high temperatures are squalene, pigments and phospholipids. Squalene and phospholipids have both been reported to retard the degradation of unsaturated fatty acids under simulated frying conditions. High chlorophyll levels were found to increase the rate of tocopherol decomposition and formation of polymers in rape seed oil heated at 180°C.

  9. Chemical constituents of selected Sudanese medicinal and aromatic plants

    Sudanese medicinal and aromatic plants (Alternanthra repens, Ambrosia maritima, Citrus paradisi, Croton zambesicus, Lepidium sativum, Morettia phillaena, Nauclea latifolia, Plectranthus barbatus, Pluchea dioscorides, and Sphaeranthus suaveolens) were analyzed for their chemical composition, mineral contents and secondary constituents. The concentration of manganese, copper, iron, nickel, lead, zinc and potassium in plant samples was performed using x-ray fluorescence spectrometry. The trace elements found in the smallest amount of the investigated plant species are lead, nickel and copper, while high concentration was detected for potassium, iron and manganese. Mn was accumulated with high level in Alternanthra repens species. Potassium was abundant in S. suaveolens and Ambrosia maritima. The values of concentration obtained for all studied elements were compared with published values of reference material, trace elements in Hay (powder) by International Atomic Energy Agency. Phyto chemical analysis of investigated plants was performed for constituents: Flavonoids, saponins, tannins, alkaloids, amino acids and sugars. The methanolic extracts of P.barbatus, C.paradisi, A.repens, N.latifolia, L. sativum and C. zambesicus are found to contain alkaloids. Results of TLC analysis were shown as Rf values for saponins, bitter principles, essential oils, flavonoids and alkaloids. Quantification of flavonoids and tannins showed that flavonoid content was highest in case of Alternanthera repens and Sphaeranthus suavertens, whereas the highest tannin content was in case of Nauclea latifolia and Sphaearanthus suavertens. The results suggest that the user of traditional Sudanese crude drugs should be warned of potential danger of heavy metal poisoning because their concentrations seem to be higher than maximum values allowed by health agencies in several countries. This study has provided some biochemical basis for the ethno medical use of extracts from different candidate plant

  10. Sucralose sweetener in vivo effects on blood constituents radiolabeling, red blood cell morphology and radiopharmaceutical biodistribution in rats

    Effects of sucralose sweetener on blood constituents labelled with technetium-99m (99mTc) on red blood cell (RBC) morphology, sodium pertechnetate (Na99mTcO4) and diethylenetriaminepentaacetic acid labeled with 99mTc (99mTc-DTPA) biodistribution in rats were evaluated. Radiolabeling on blood constituents from Wistar rats was undertaken for determining the activity percentage (%ATI) on blood constituents. RBC morphology was also evaluated. Na99mTcO4 and 99mTc-DTPA biodistribution was used to determine %ATI/g in organs. There was no alteration on RBC blood constituents and morphology %ATI. Sucralose sweetener was capable of altering %ATI/g of the radiopharmaceuticals in different organs. These findings are associated to the sucralose sweetener in specific organs.

  11. Ginkgo biloba extract alters the binding of the sodium [123I] iodide (Na123I) on blood constituents

    We evaluated the in vitro effect of an aqueous extract of Ginkgo biloba (EGb) on the distribution in blood cells (BC) and plasma (P) and on the binding of Na123I to the blood constituents using precipitation with trichloroacetic acid. The radioactivity percentages insoluble (SF) and insoluble fraction (IF) of blood constituents were determined. The EGb interfered (p123I in the P (from 69.64 to 86.13) and BC (from 30.36 to 13.87) and altered the fixation of the Na123I in IF-P and in IF-BC. - Highlights: ► Interaction between the Ginkgo biloba and blood constituents radiolabeled. ► Modification of the binding of sodium iodide (Na123I) to the blood constituents. ► This alteration should have influence in a diagnosis of nuclear medicine.

  12. Sucralose sweetener in vivo effects on blood constituents radiolabeling, red blood cell morphology and radiopharmaceutical biodistribution in rats

    Rocha, G.S.; Pereira, M.O. [Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamento de Biofisica e Biometria, Avenida 28 de Setembro, 87, Vila Isabel, 20551030 Rio de Janeiro (Brazil); Universidade Federal do Rio Grande do Norte, Programa de Pos-Graduacao em Ciencias da Saude, Avenida General Gustavo Cordeiro de Farias, s/n, 59010180 Natal, Rio Grande do Norte (Brazil); Benarroz, M.O.; Frydman, J.N.G.; Rocha, V.C. [Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamento de Biofisica e Biometria, Avenida 28 de Setembro, 87, Vila Isabel, 20551030 Rio de Janeiro (Brazil); Pereira, M.J. [Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamento de Fisiologia, Avenida 28 de Setembro, 87, Vila Isabel, 20551030 Rio de Janeiro (Brazil); Fonseca, A.S., E-mail: adnfonseca@ig.com.b [Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamento de Biofisica e Biometria, Avenida 28 de Setembro, 87, Vila Isabel, 20551030 Rio de Janeiro (Brazil); Universidade Federal do Estado do Rio de Janeiro, Instituto Biomedico, Departamento de Ciencias Fisiologicas, Rua Frei Caneca, 94, Rio de Janeiro 20211040 (Brazil); Medeiros, A.C. [Universidade Federal do Rio Grande do Norte, Programa de Pos-Graduacao em Ciencias da Saude, Avenida General Gustavo Cordeiro de Farias, s/n, 59010180 Natal, Rio Grande do Norte (Brazil); Bernardo-Filho, M. [Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamento de Biofisica e Biometria, Avenida 28 de Setembro, 87, Vila Isabel, 20551030 Rio de Janeiro (Brazil); Instituto Nacional do Cancer, Coordenadoria de Pesquisa Basica, Praca Cruz Vermelha, 23, 20230130 Rio de Janeiro (Brazil)

    2011-01-15

    Effects of sucralose sweetener on blood constituents labelled with technetium-99m ({sup 99m}Tc) on red blood cell (RBC) morphology, sodium pertechnetate (Na{sup 99m}TcO{sub 4}) and diethylenetriaminepentaacetic acid labeled with {sup 99m}Tc ({sup 99m}Tc-DTPA) biodistribution in rats were evaluated. Radiolabeling on blood constituents from Wistar rats was undertaken for determining the activity percentage (%ATI) on blood constituents. RBC morphology was also evaluated. Na{sup 99m}TcO{sub 4} and {sup 99m}Tc-DTPA biodistribution was used to determine %ATI/g in organs. There was no alteration on RBC blood constituents and morphology %ATI. Sucralose sweetener was capable of altering %ATI/g of the radiopharmaceuticals in different organs. These findings are associated to the sucralose sweetener in specific organs.

  13. Constructing Gold-thiolate Oligomers and Polymers on Au(111) Based on the Linear S-Au-S Geometry

    Jiang, Deen [ORNL; Dai, Sheng [ORNL

    2009-01-01

    Although neat gold-thiolate oligomers and polymers made of linear S-Au-S bonds have been well-known, observation of RS-Au-SR linear complexes (RS-being an alkylthiolate group) on Au(111) has been reported only recently. On the basis of the unique geometry and bonding of the RS-Au-SR complex on Au(111), we construct simple geometric models of Au-SR oligomers and polymers on Au(111) by fusing linear S-Au-S units matched to the underlying Au(111) surface lattice. We then optimize these models by density functional theory. The hexagonal geometry of the Au(111) lattice determines three possible angles (60{sup o}, 120{sup o}, and 180{sup o}) for connecting two linear S-Au-S units, which lead to isomerism of the Au-SR oligomers and polymer on Au(111). Here we explore open dimers, trimers, and tetramers and cyclic trimers, tetramers, and hexamers of the Au-SR oligomers on Au(111). We also examine four isomers of the Au-SR polymer on Au(111). We find that the 120{sup o} Au-S-Au angle is preferred in constructing both oligomeric and polymeric isomers. The two polymeric isomers with 120{sup o} Au-S-Au angles are found to be energetically competitive with a previous model proposed for the Au-SR polymer on Au(111). We also discuss potential ways to create Au-SR oligomers on Au(111).

  14. Constructing Gold-Thiolate Oligomers and Polymers on Au(111) Based on the Linear S-Au-S Geometry

    Dai, Sheng [ORNL; Jiang, Deen [ORNL

    2009-01-01

    Although neat gold-thiolate oligomers and polymers made of linear S-Au-S bonds have been well-known, observation of RS-Au-SR linear complexes (RS- being an alkylthiolate group) on Au(111) has been reported only recently. On the basis of the unique geometry and bonding of the RS-Au-SR complex on Au(111), we construct simple geometric models of Au-SR oligomers and polymers on Au(111) by fusing linear S-Au-S units matched to the underlying Au(111) surface lattice. We then optimize these models by density functional theory. The hexagonal geometry of the Au(111) lattice determines three possible angles (60{sup o}, 120{sup o}, and 180{sup o}) for connecting two linear S-Au-S units, which lead to isomerism of the Au-SR oligomers and polymer on Au(111). Here we explore open dimers, trimers, and tetramers and cyclic trimers, tetramers, and hexamers of the Au-SR oligomers on Au(111). We also examine four isomers of the Au-SR polymer on Au(111). We find that the 120{sup o} Au-S-Au angle is preferred in constructing both oligomeric and polymeric isomers. The two polymeric isomers with 120{sup o} Au-S-Au angles are found to be energetically competitive with a previous model proposed for the Au-SR polymer on Au(111). We also discuss potential ways to create Au-SR oligomers on Au(111).

  15. Selective amyloid β oligomer assay based on abasic site-containing molecular beacon and enzyme-free amplification.

    Zhu, Linling; Zhang, Junying; Wang, Fengyang; Wang, Ya; Lu, Linlin; Feng, Chongchong; Xu, Zhiai; Zhang, Wen

    2016-04-15

    Amyloid-beta (Aβ) oligomers are highly toxic species in the process of Aβ aggregation and are regarded as potent therapeutic targets and diagnostic markers for Alzheimer's disease (AD). Herein, a label-free molecular beacon (MB) system integrated with enzyme-free amplification strategy was developed for simple and highly selective assay of Aβ oligomers. The MB system was constructed with abasic site (AP site)-containing stem-loop DNA and a fluorescent ligand 2-amino-5,6,7-trimethyl-1,8-naphyridine (ATMND), of which the fluorescence was quenched upon binding to the AP site in DNA stem. Enzyme-free amplification was realized by target-triggered continuous opening of two delicately designed MBs (MB1 and MB2). Target DNA hybridization with MB1 and then MB2 resulted in the release of two ATMND molecules in one binding event. Subsequent target recycling could greatly amplify the detection sensitivity due to the greatly enhanced turn-on emission of ATMND fluorescence. Combining with Aβ oligomers aptamers, the strategy was applied to analyze Aβ oligomers and the results showed that it could quantify Aβ oligomers with high selectivity and monitor the Aβ aggregation process. This novel method may be conducive to improve the diagnosis and pathogenic study of Alzheimer's disease. PMID:26613510

  16. Investigation of intermolecular interactions between single walled nanotubes and conjugated oligomers using the dispersion-corrected DFT methods

    Lagowski, Jolanta B.; Aljohani, Suad; Khan, M. Zahidul H.; Zhao, Yuming

    The area of carbon nanotubes (CNT)-polymer composites has been progressing rapidly in recent years. Pure CNT and CNT-polymer composites have many useful (industry related) properties: ranging from electronic electrical conductivity to superior strength. However the full potential of using CNTs as reinforcements (in say a polymer matrix) has been severely limited because of complications associated with the dispersion of CNTs. CNTs tend to entangle with each other forming materials that have properties that fall short of the expectations. The goal of this work is to identify the type of conjugated oligomers that are best suited for the dispersion of single walled CNT (SWCNT). For this purpose, various methods of dispersion corrected density functional theory (DFT-D/B97D, /WB97XD, /CAM-B3LYP) have been used to investigate the interaction between the SWCNT and the organic conjugated oligomers with different end groups (aldehyde (ALD) and dithiafulvenyl (DTF)). We investigate the effect of intermolecular interactions on the structure, polarity and energetics of the oligomers and SWCNT combinations. The comparison of results obtained using different DFT approximations is made. Our results show that DFT-endcapped oligomer interact more strongly with CNT than ALD-endcapped oligomer. The financial support from NSERC, SACBC and Memorial University and the computational resources from Compute Canada were received.

  17. Assembly of Heterometallic Rigid-Rod Complexes and Coordination Oligomers from Gold(I) Metalloligands.

    Cámara, Verónica; Barquero, Natalia; Bautista, Delia; Gil-Rubio, Juan; Vicente, José

    2015-07-01

    The reactions of TpylC6H4C≡CAuL (Tpyl = 2,2':6',2″-terpyridin-4'-yl; L = PPh3, CNXy; Xy = 2,6-dimethylphenyl) with MX2·nH2O (M = Fe, X = ClO4; M = Co, X = BF4; M = Zn, X = TfO, ClO4) in a 2:1 molar ratio give complexes [M(TpylC6H4C≡CAuL)2]X2. Similarly, the reactions of PPN[(TpylC6H4C≡C)2Au] (PPN = (Ph3P)2N) with an equimolar amount of MX2·nH2O give coordination oligomers [M{(TpylC6H4C≡C)2Au}]nXn (M = Fe, Zn, X = ClO4; M = Co, X = BF4). The complexes and oligomers have been isolated and characterized. The crystal structures of [Fe(TpylC6H4C≡CAuCNXy)2](ClO4)2 and [Co(TpylC6H4C≡CAuPPh3)2](BF4)2 have been determined by X-ray diffraction. The hydrodynamic sizes of complexes [M(TpylC6H4C≡CAuPPh3)2]X2 and coordination oligomers [M{(TpylC6H4C≡C)2Au}]nXn have been studied by NMR diffusion spectroscopy and dynamic light scattering measurements. PMID:26087239

  18. Environmental enrichment strengthens corticocortical interactions and reduces amyloid-β oligomers in aged mice.

    Mainardi, Marco; Di Garbo, Angelo; Caleo, Matteo; Berardi, Nicoletta; Sale, Alessandro; Maffei, Lamberto

    2014-01-01

    Brain aging is characterized by global changes which are thought to underlie age-related cognitive decline. These include variations in brain activity and the progressive increase in the concentration of soluble amyloid-β (Aβ) oligomers, directly impairing synaptic function and plasticity even in the absence of any neurodegenerative disorder. Considering the high social impact of the decline in brain performance associated to aging, there is an urgent need to better understand how it can be prevented or contrasted. Lifestyle components, such as social interaction, motor exercise and cognitive activity, are thought to modulate brain physiology and its susceptibility to age-related pathologies. However, the precise functional and molecular factors that respond to environmental stimuli and might mediate their protective action again pathological aging still need to be clearly identified. To address this issue, we exploited environmental enrichment (EE), a reliable model for studying the effect of experience on the brain based on the enhancement of cognitive, social and motor experience, in aged wild-type mice. We analyzed the functional consequences of EE on aged brain physiology by performing in vivo local field potential (LFP) recordings with chronic implants. In addition, we also investigated changes induced by EE on molecular markers of neural plasticity and on the levels of soluble Aβ oligomers. We report that EE induced profound changes in the activity of the primary visual and auditory cortices and in their functional interaction. At the molecular level, EE enhanced plasticity by an upward shift of the cortical excitation/inhibition balance. In addition, EE reduced brain Aβ oligomers and increased synthesis of the Aβ-degrading enzyme neprilysin. Our findings strengthen the potential of EE procedures as a non-invasive paradigm for counteracting brain aging processes. PMID:24478697

  19. ENVIRONMENTAL ENRICHMENT STRENGTHENS CORTICOCORTICAL INTERACTIONS AND REDUCES AMYLOID-β OLIGOMERS IN AGED MICE

    Marco eMainardi

    2014-01-01

    Full Text Available Brain aging is characterized by global changes which are thought to underlie age-related cognitive decline. These include variations in brain activity and the progressive increase in the concentration of soluble amyloid-β (Aβ oligomers, directly impairing synaptic function and plasticity even in the absence of any neurodegenerative disorder. Considering the high social impact of the decline in brain performance associated to aging, there is an urgent need to better understand how it can be prevented or contrasted. Lifestyle components, such as social interaction, motor exercise and cognitive activity, are thought to modulate brain physiology and its susceptibility to age-related pathologies. However, the precise functional and molecular factors that respond to environmental stimuli and might mediate their protective action again pathological aging still need to be clearly identified. To address this issue, we exploited environmental enrichment (EE, a reliable model for studying the effect of experience on the brain based on the enhancement of cognitive, social and motor experience, in aged wild-type mice. We analyzed the functional consequences of EE on aged brain physiology by performing in vivo local field potential (LFP recordings with chronic implants. In addition, we also investigated changes induced by EE on molecular markers of neural plasticity and on the levels of soluble Aβ oligomers. We report that EE induced profound changes in the activity of the primary visual and auditory cortices and in their functional interaction. At the molecular level, EE enhanced plasticity by an upward shift of the cortical excitation/inhibition balance. In addition, EE reduced brain Aβ oligomers and increased synthesis of the Aβ-degrading enzyme neprilysin. Our findings strengthen the potential of EE procedures as a non-invasive paradigm for counteracting brain aging processes.

  20. Lipid constituents of marine sponge Suberites carnosus

    Mishra, P.D; Wahidullah, S.; DeSouza, L.; Kamat, S.Y.

    Sterols (22E) - 24- methyl-cholest - 4, 8(9), 22(23) - triene - 3, 7 - diol (1) and (22E)-24-methyl-ergost-6, 22(23)-diene-5, 8-epidioxy-3-ol (2), a fatty acid nonadecanoic acid and a fatty ester methyl nonadecanoate have been isolated from...

  1. Immunosuppressive Effects of A-Type Procyanidin Oligomers from Cinnamomum tamala

    Liang Chen; Yang Yang; Pulong Yuan; Yifu Yang; Kaixian Chen; Qi Jia; Yiming Li

    2014-01-01

    Cinnamon barks extracts have been reported to regulate immune function; however, the component(s) in cinnamon barks responsible for this effect is/are not yet clear. The aim of this study is to find out the possible component(s) that can be used as therapeutic agents for immune-related diseases from cinnamon bark. In this study, the immunosuppressive effects of fraction (named CT-F) and five procyanidin oligomers compounds, cinnamtannin B1, cinnamtannin D1 (CTD-1), parameritannin A1, procyani...

  2. π-CONJUGATED OLIGOMERS IN SUPRAMOLECULAR CRYSTALS AND THEIR OPTOELECTRONIC FUNCTIONS

    Zeng-qi Xie; Bing Yang; Yu-guang Ma; Jia-cong Shen

    2007-01-01

    Functional organic molecular materials and conjugated oligomers or polymers now allow the low-cost fabrication of thin films for insertion into new generations of electronic and optoelectronic devices. The performance of these devices relies on the understanding and optimization of several complementary processes. Our goal is to discuss the relationship between the molecular stacking structures and their optoelectronic properties that are of importance in all these areas. The concept of intermolecular interaction should be taken here in the special sense that is inter-dipole coupling. Specifically, we will address the impact of inter-dipole interaction between adjacent molecules in aggregate state on the solid-state emission properties.

  3. SYNTHESES OF POLYSTYRENE RESINS CONTAINING POLYETHER OLIGOMERS AND THEIR EXTRACTION FOR GOLD (Ⅲ)

    DONG Shihua; LIU Shi; XU Yuwu

    1994-01-01

    Three polystyrene resins containing polyether oligomers as extractants were synthesized and their extraction properties were studied. Gold (Ⅲ) ion could be extracted rapidly by the resins (T1/2<1min.)with high efficiency and capacity (for LS-B resin that were 99.8% and 95.8mg/gR respectively) from aqueous solution but most of the co-existing metal ions such as Pd (Ⅱ),Cu(Ⅱ), Zn (Ⅱ), Pb (Ⅱ) and Cd (Ⅱ) were remained. The extraction capacity and stripping percentage for gold (Ⅲ) remained unchanged in four extraction-stripping cycles. The resins also showed good column extraction-elution properties.

  4. Inhibition of Gene Expression in Escherichia coli by Antisense Phosphorodiamidate Morpholino Oligomers

    Geller, B L; Deere, J. D.; Stein, D A; Kroeker, A. D.; Moulton, H. M.; Iversen, P. L.

    2003-01-01

    Antisense phosphorodiamidate morpholino oligomers (PMOs) were tested for the ability to inhibit gene expression in Escherichia coli. PMOs targeted to either a myc-luciferase reporter gene product or 16S rRNA did not inhibit luciferase expression or growth. However, in a strain with defective lipopolysaccharide (lpxA mutant), which has a leaky outer membrane, PMOs targeted to the myc-luciferase or acyl carrier protein (acpP) mRNA significantly inhibited their targets in a dose-dependent respon...

  5. Prediction of Excitation Energies for Conjugated Oligomers and Polymers from Time-Dependent Density Functional Theory

    Jianmin Tao

    2010-05-01

    Full Text Available With technological advances, light-emitting conjugated oligomers and polymers have become competitive candidates in the commercial market of light-emitting diodes for display and other technologies, due to the ultralow cost, light weight, and flexibility. Prediction of excitation energies of these systems plays a crucial role in the understanding of their optical properties and device design. In this review article, we discuss the calculation of excitation energies with time-dependent density functional theory, which is one of the most successful methods in the investigation of the dynamical response of molecular systems to external perturbation, owing to its high computational efficiency.

  6. Seasonal variations of the phenolic constituents in bilberry (Vaccinium myrtillus L.) leaves, stems and fruits, and their antioxidant activity.

    Bujor, Oana-Crina; Le Bourvellec, Carine; Volf, Irina; Popa, Valentin I; Dufour, Claire

    2016-12-15

    The seasonal variations of the content and diversity of phenolic compounds, as well as the antioxidant activity of leaves, stems and fruits of bilberry collected in May, July and September, were evaluated for two consecutive years. UPLC/MS(n) analyses showed the predominance of anthocyanins in fruits, caffeic acid derivatives in leaves whereas flavanol oligomers represented more than half of the phenolic compounds in stems. Thioacidolysis revealed degrees of polymerization between 2 and 4 and (-)-epicatechin as the main flavanol unit. The sum of the phenolic compounds by UPLC was highly correlated with the total polyphenol content and the antioxidant activity in the DPPH test for all the extracts except for May leaves. The latter were relatively rich in p-coumaric acid derivatives. Seasonal effects were more marked for leaves, which exhibited higher antioxidant activities and phenolic contents in July and September when these parameters were at their highest in July for stems. PMID:27451155

  7. ANTICANCER ACTIVITY OF ISOLATED CHEMICAL CONSTITUENTS FROM MILIUSA SMITHIAE

    Chonthicha Naphong; Wilart Pompimon; Punchavee Sombutsiri

    2013-01-01

    Miliusa plants belonging to the family Annonaceae are found in Thailand and have been used as Thai traditional medicines. There have been a few previously reports on the chemical constituents of plants in this genus, describing the presence of aporphine alkaloids, terpenoids, flavonoids, phenylpropanoids, styrylpyrones, bis-styryls and homogentisic acid derivatives. Miliusa smithiae, a new species for Thailand and world, has not been studied chemical composition. The present study described p...

  8. Anti-Inflammatory Activities of Cinnamomum cassia Constituents In Vitro and In Vivo

    Jung-Chun Liao; Jeng-Shyan Deng; Chuan-Sung Chiu; Wen-Chi Hou; Shyh-Shyun Huang; Pei-Hsin Shie; Guang-Jhong Huang

    2012-01-01

    We have investigated the anti-inflammatory effects of Cinnamomum cassia constituents (cinnamic aldehyde, cinnamic alcohol, cinnamic acid, and coumarin) using lipopolysaccharide (LPS)-stimulated mouse macrophage (RAW264.7) and carrageenan (Carr)-induced mouse paw edema model. When RAW264.7 macrophages were treated with cinnamic aldehyde together with LPS, a significant concentration-dependent inhibition of nitric oxide (NO), tumor necrosis factor (TNF- α ), and prostaglandin E2 (PGE2) levels p...

  9. A Spotlight on Chemical Constituents and Pharmacological Activities of Nigella glandulifera Freyn et Sint Seeds

    Ping Li; Xiao-Lan Cheng; Xin-Guang Liu; Besma Boubertakh

    2013-01-01

    Plants belonging to the Ranunculaceae family, and particularly their seeds, have been a hot research topic in numerous pharmacognosy laboratories. Nigella glandulifera Freyn et Sint (NG) is one of the promising, but relatively insufficiently studied, plants from this family. In this review, we summarize the recently isolated chemical constituents from the seeds of this plant including alkaloids, flavonol glycosides, isobenzofuranone derivatives, saponins, terpenes, terpenoids, and fatty acids...

  10. Antioxidant activities and phenolic constituents of Cephalotaxus oliveri Mast. aerial parts

    Zeng Lingbin; Vrijmoed L.L.P.

    2012-01-01

    The present study was to analyze the antioxidant activity and the responsible chemical constituents in Cephalotaxus oliveri Mast. aerial parts. DPPH (2,2-diphenyl-1-picryl hydrazyl), ABTS [2,2’-azinobis(3-ethylbenzothiazoline- 6-sulfonic acid)], reducing power and total phenolic content assays indicate that the methanol extract of the aerial parts is the most potent radical-scavenger and reducing agent with the highest level of phenolic content among the test extracts. The highly posit...

  11. Biofunctional Constituents from Liriodendron tulipifera with Antioxidants and Anti-Melanogenic Properties

    Chung-Yi Chen; Po-Len Liu; Zhi-Hong Wen; Pei-Fang Wu; Yi-Chieh Lin; Wei-Jen Li; Hui-Min Wang

    2013-01-01

    From the stems of Liriodendron tulipifera, seventeen known compounds have been extracted, isolated and purified. By using spectroscopic analysis, the structures of these pure constituents were determined as three lignans, four steroids and ten benzenoids. Identified compounds were screened for antioxidant abilities using: 1,1-diphenyl-2-picrylhydrazul (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging free radical activity assays; metal chelating power te...

  12. The spermatogenic effect of yacon extract and its constituents and their inhibition effect of testosterone metabolism.

    Park, Jeong Sook; Han, Kun

    2013-03-01

    We screened the pharmacological effects of a 50% ethanol extract of Yacon tubers and leaves on spermatogenesis in rats. As a result, we found that Yacon tuber extracts increased sperm number and serum testosterone level in rats. It has been reported that the crude extract of Yacon tubers and leaves contain phenolic acids, such as, chlorogenic acid, ferulic acid and caffeic acid by HPLC/MS analysis. We were interested in the contributions made by phenolic acid, particularly chlorogenic acid of Yacon tuber extract to the spermatogenic activity. After administering Yacon tuber extract or chlorogenic acid to rats for 5 weeks, numbers of sperm in epididymis were increased by 34% and 20%, respectively. We also administered ferulic acid, which has been reported to be a metabolite of chlorogenic acid and a constituent of Yacon tuber extract to investigate its spermatogenic activity in rats. Yacon tuber extract and ferulic acid increased sperm numbers by 43% and 37%, respectively. And, Yacon tuber extract, and chlorogenic acid showed significantly inhibition effect of testoeterone degradation in rat liver homogenate. We considered that the spermatogenic effect of Yacon tuber extract might be related to phenolic compounds and their inhibitory effect of testosterone degradation. Yacon showed the possibility as ameliorable agents of infertility by sperm deficiency and late onset hypogonadism syndrome with low level of testosterone. PMID:24009874

  13. Bioactive Constituents and Antioxidant Activity of Some Carpathian Basin honeys.

    Gyergyák, Kinga; Boros, Borbála; Marton, Krisztina; Felinger, Attila; Papp, Nóra; Farkas, Ágnes

    2016-02-01

    Unifloral honeys have a high commercial value and should undergo a strict quality control before marketing. This study aimed at determining floral origin, polyphenolic compounds and antioxidant activity in 7 samples marketed as lavender and thyme honeys. The samples were subjected to pollen analysis to confirm their botanical origin. Coupled chromatographic techniques (HPLC-DAD-ESI-MS) were optimized for the separation and identification of polyphenolic compounds. The antioxidant properties of the samples were determined by spectrophotometric methods. Pollen profile analysis revealed that only 3 out of 5 alleged lavender honeys contained a low percentage (0.6-1.5) of lavender pollen; and there were only traces (0.1-0.6%) of thyme pollen in the alleged thyme honeys. Polyphenolic constituents did not allow for the clear separation of honey samples, revealing no marker compounds previously associated with lavender and thyme honeys. All samples contained large amounts of chlorogenic acid, chrysin, hesperetin, kaempferol and p-coumaric acid; as well as abscisic acid, a plant hormone known to be present in floral nectar and honey. Our results suggest that only one of five alleged lavender honeys and neither of the two alleged thyme honeys are true unifloral honeys. However, they can still provide various health benefits, such as being good sources of antioxidants. There was no relationship between the antioxidant activity and the uni- or multifloral character of the honey samples. Total phenolic content and antioxidant activity was the lowest in the honey sample with lavender and the highest in one of the alleged lavender honeys. Our findings highlight the importance of microscopical and phytochemical analyses of honeys before marketing, to ensure satisfactory quality for customers. PMID:27032212

  14. Dibaryons in a constituent quark model

    Park, Woosung; Lee, Su Houng

    2015-01-01

    We investigate the properties of dibaryons containing u and d quarks in the constituent quark model. In constructing the ground state wave function, we choose the spatial part to be fully symmetric and the remaining color, isospin and spin part to be antisymmetric so as to satisfy the the Pauli principle. By adapting the IS coupling scheme that combine the isospin basis function with the spin basis function, and subsequently coupling this to the color singlet basis function, we construct the color $\\otimes$ isospin $\\otimes$ spin states compatible with the physical states of the dibaryon. By using the variational method, we then calculate the mass of the dibaryon in a nonrelativistic potential model, involving Coulomb, color confinement and color-spin hyperfine interaction. In particular, to asses the stability for different types of the confinement potential, we introduce one that is linearly proportional to the interquark distance and another to its square root. For all cases considered, we find that there ...

  15. LHCb pentaquarks in constituent quark models

    Ortega, P G; Fernández, F

    2016-01-01

    The recently discovered $P_c(4380)^+$ and $P_c(4450)^+$ states at LHCb have masses close to the $\\bar D\\Sigma_c^*$ and $\\bar D^*\\Sigma_c$ thresholds, respectively, which suggest that they may have significant meson-baryon molecular components. We analyze these states in the framework of a constituent quark model which has been applied to a wide range of hadronic observables, being the model parameters, therefore, completely constrained. The $P_c(4380)^+$ and $P_c(4450)^+$ are studied as molecular states composed by charmed baryons and open charm mesons. Several bound states with the proper binding energy are found in the $\\bar D\\Sigma_c^*$ and $\\bar D^*\\Sigma_c$ channels. We discuss the possible assignments of these states from their decay widths. Moreover, two more states are predicted, associated with the $\\bar D\\Sigma_c$ and $\\bar D^* \\Sigma_c^*$ thresholds.

  16. Constituent gluons and the static quark potential

    Greensite, Jeff

    2015-01-01

    We suggest that Hamiltonian matrix elements between physical states in QCD might be approximated, in Coulomb gauge, by "lattice-improved" tree diagrams; i.e. tree diagram contributions with dressed ghost, transverse gluon, and Coulomb propagators obtained from lattice simulations. Such matrix elements can be applied to a variational treatment of hadronic states which include constituent gluons. As an illustration and first application of this hybrid approach, we derive a variational estimate of the heavy quark potential for distances up to 2.5 fm. The Coulomb string tension in SU(3) gauge theory is about a factor of four times greater than the asymptotic string tension. In our variational approach, using for simplicity a single variational parameter, we can reduce this overshoot by nearly the factor required. The building blocks of our approach are Coulomb gauge propagators, and in this connection we present new lattice results for the ghost and transverse gluon propagators in position space.

  17. Multi-Constituent Simulation of Thrombus Deposition

    Wu, Wei-Tao; Massoudi, Mehrdad; Wagner, William R; Antaki, James F

    2016-01-01

    Based on the transport model of Sorensen et al. (1999), an improved mathematical model describing the process of thrombus deposition and growth was developed. Blood is treated as a multi-constituent mixture comprised of a linear fluid phase and a thrombus phase. The transport and reactions of 10 chemical and biological species are modeled using a system of coupled convection-reaction-diffusion (CRD) equations. These represent three main processes: initiation, propagation and stabilization. Computational fluid dynamic (CFD) simulations using the libraries of OpenFOAM were performed for two illustrative benchmark problems: mural thrombus growth in an injured blood vessel and thrombus deposition in a small (125 x 95 micros) crevice observed in vitro. For both problems, the simulated thrombus deposition agreed very well with experimental observations, both spatially and temporally. These promising results encourage further simulations to investigate clinical conditions and design factors that affect the risk of t...

  18. Constituent gluons and the static quark potential

    Greensite, Jeff [San Francisco State Univ., CA (United States); Szczepaniak, Adam P. [Indiana Univ., Bloomington, IN (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-04-01

    We suggest that Hamiltonian matrix elements between physical states in QCD might be approximated, in Coulomb gauge, by "lattice-improved" tree diagrams; i.e. tree diagram contributions with dressed ghost, transverse gluon, and Coulomb propagators obtained from lattice simulations. Such matrix elements can be applied to a variational treatment of hadronic states which include constituent gluons. As an illustration and first application of this hybrid approach, we derive a variational estimate of the heavy quark potential for distances up to 2.5 fm. The Coulomb string tension in SU(3) gauge theory is about a factor of four times greater than the asymptotic string tension. In our variational approach, using for simplicity a single variational parameter, we can reduce this overshoot by nearly the factor required. The building blocks of our approach are Coulomb gauge propagators, and in this connection we present new lattice results for the ghost and transverse gluon propagators in position space.

  19. SYNTHESIS, CHARACTERIZATION, THERMAL DEGRADATION AND ELECTRICAL CONDUCTIVITY OF OLIGO[2-(2-HYDROXYPHENYLIMINOMETHYLBENZYLIDENE)AMINOPHENOL]AND OLIGOMER-METAL COMPLEXES

    (I)smet Kaya; S(u)leyman Culhao(g)lu

    2008-01-01

    The oxidative polycondensation reaction conditions of 2-[(2-hydroxyphenyliminomethylbenzylidene)amino-phenol] (2-HPIMBAP) has been accomplished by using air O2 and NaOCl oxidants in an aqueous alkaline medium between50-90℃. The optimum reaction conditions of the oxidative polycondensation and the main parameters of the process wereestablished. At the optimum reaction conditions, yield of the products were found to be 67.72% and 61.49% for air O2 andNaOCl oxidants respectively. The structures of the monomer and oligomer were confirmed by FT-IR, UV-Vis, 1H-NMR and13C-NMR and elemental analysis. Also, TGA-DTA, SEC techniques and solubility tests were applied for characterization.1H-NMR and 13C-NMR data show that the polymerization proceeded by the C-C and C-O-C coupling systems of orthoand para positions and oxyphenylene according to-OH group of 2-HPIMBAP. The number-average molecular weight(Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of oligo[2-(2-hydroxyphenyliminomethylbenzylidene)aminophenol] (oligo(2-HPIMBAP)) were determined. Thermal analyses of oligomer-metal complexeswere investigated in N2 atmosphere between 15-1000℃. Electrical conductivities of oligo(2-HPIMBAP) and oligomer-metalcomplexes measured with four point technique. Electrical conductivity of the oligo(2-HPIMBAP) was measured, showingthat the oligomer is a typical semiconductor. Optical band gaps (Eg) of 2-HPIMBAP, oligo(2-HPIMBAP) and oligomer-metal complex compounds were determined by UV-Vis measurements. The monomer and oligomer were screened forantibacterial activities.

  20. Length dependence of rectification in organic co-oligomer spin rectifiers

    Gui-Chao, Hu; Zhao, Zhang; Ying, Li; Jun-Feng, Ren; Chuan-Kui, Wang

    2016-05-01

    The rectification ratio of organic magnetic co-oligomer diodes is investigated theoretically by changing the molecular length. The results reveal two distinct length dependences of the rectification ratio: for a short molecular diode, the charge-current rectification changes little with the increase of molecular length, while the spin-current rectification is weakened sharply by the length; for a long molecular diode, both the charge-current and spin-current rectification ratios increase quickly with the length. The two kinds of dependence switch at a specific length accompanied with an inversion of the rectifying direction. The molecular ortibals and spin-resolved transmission analysis indicate that the dominant mechanism of rectification suffers a change at this specific length, that is, from asymmetric shift of molecular eigenlevels to asymmetric spatial localization of wave functions upon the reversal of bias. This work demonstrates a feasible way to control the rectification in organic co-oligomer spin diodes by adjusting the molecular length. Project supported by the National Natural Science Foundation of China (Grant No. 11374195), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2014AM017), the Taishan Scholar Project of Shandong Province, China, and the Excellent Young Scholars Research Fund of Shandong Normal University, China.

  1. Immunosuppressive Effects of A-Type Procyanidin Oligomers from Cinnamomum tamala

    Liang Chen

    2014-01-01

    Full Text Available Cinnamon barks extracts have been reported to regulate immune function; however, the component(s in cinnamon barks responsible for this effect is/are not yet clear. The aim of this study is to find out the possible component(s that can be used as therapeutic agents for immune-related diseases from cinnamon bark. In this study, the immunosuppressive effects of fraction (named CT-F and five procyanidin oligomers compounds, cinnamtannin B1, cinnamtannin D1 (CTD-1, parameritannin A1, procyanidin B2, and procyanidin C1, from Cinnamomum tamala or Cinnamomum cassia bark were examined on splenocytes proliferation model induced by ConA or LPS. Then, the effects of activated compound CTD-1 on cytokine production and 2,4-dinitrofluorobenzene (DNFB induced delayed-type hypersensitivity (DTH response were detected to evaluate the immunosuppressive activity of CTD-1. It was found that CT-F and CTD-1 significantly inhibited the splenocyte proliferation induced by ConA or LPS. CTD-1 dose-dependently reduced the level of IFN-γ and IL-2 and intensively suppressed DNFB-induced DTH responses. These findings suggest that the immunosuppressive activities of cinnamon bark are in part due to procyanidin oligomers. CTD-1 may be a potential therapeutic agent for immune-related diseases.

  2. Oligomer formation in the troposphere: from experimental knowledge to 3-D modeling

    Lemaire, Vincent; Coll, Isabelle; Couvidat, Florian; Mouchel-Vallon, Camille; Seigneur, Christian; Siour, Guillaume

    2016-04-01

    The organic fraction of atmospheric aerosols has proven to be a critical element of air quality and climate issues. However, its composition and the aging processes it undergoes remain insufficiently understood. This work builds on laboratory knowledge to simulate the formation of oligomers from biogenic secondary organic aerosol (BSOA) in the troposphere at the continental scale. We compare the results of two different modeling approaches, a first-order kinetic process and a pH-dependent parameterization, both implemented in the CHIMERE air quality model (AQM) (www.lmd.polytechnique.fr/chimere), to simulate the spatial and temporal distribution of oligomerized secondary organic aerosol (SOA) over western Europe. We also included a comparison of organic carbon (OC) concentrations at two EMEP (European Monitoring and Evaluation Programme) stations. Our results show that there is a strong dependence of the results on the selected modeling approach: while the irreversible kinetic process leads to the oligomerization of about 50 % of the total BSOA mass, the pH-dependent approach shows a broader range of impacts, with a strong dependency on environmental parameters (pH and nature of aerosol) and the possibility for the process to be reversible. In parallel, we investigated the sensitivity of each modeling approach to the representation of SOA precursor solubility (Henry's law constant values). Finally, the pros and cons of each approach for the representation of SOA aging are discussed and recommendations are provided to improve current representations of oligomer formation in AQMs.

  3. Ring-like oligomers of Synaptotagmins and related C2 domain proteins

    Zanetti, Maria N; Bello, Oscar D; Wang, Jing; Coleman, Jeff; Cai, Yiying; Sindelar, Charles V; Rothman, James E; Krishnakumar, Shyam S

    2016-01-01

    We recently reported that the C2AB portion of Synaptotagmin 1 (Syt1) could self-assemble into Ca2+-sensitive ring-like oligomers on membranes, which could potentially regulate neurotransmitter release. Here we report that analogous ring-like oligomers assemble from the C2AB domains of other Syt isoforms (Syt2, Syt7, Syt9) as well as related C2 domain containing protein, Doc2B and extended Synaptotagmins (E-Syts). Evidently, circular oligomerization is a general and conserved structural aspect of many C2 domain proteins, including Synaptotagmins. Further, using electron microscopy combined with targeted mutations, we show that under physiologically relevant conditions, both the Syt1 ring assembly and its rapid disruption by Ca2+ involve the well-established functional surfaces on the C2B domain that are important for synaptic transmission. Our data suggests that ring formation may be triggered at an early step in synaptic vesicle docking and positions Syt1 to synchronize neurotransmitter release to Ca2+ influx. DOI: http://dx.doi.org/10.7554/eLife.17262.001 PMID:27434670

  4. Synchrotron radiation small angle scattering studies of d(TTAGGG)4 oligomer in solution

    Telomeric DNA sequences play a crucial role in maintaining chromosome stability and integrity. In human chromosomes telomeres are composed of tandem (TTAGGG)n repeats. The structural parameters and low-resolution structure of a synthetic d(TTAGGG)4 oligomer in solution has been studied in the absence and in the presence of potassium cations, with the use of the small angle scattering of synchrotron radiation. The radii of gyration RG, calculated for d(TTAGGG)4 oligomer (in 10 mM Tris/HCl pH 7.3) was 1.42 nm, while RG, (in 10 mM Tris/HCl pH 7.3; 0.1 mM KCl) was 1.32 nm. The pair distance distribution function, P(r), yielded a maximum dimension of 4.55and 4.35 nm for solutions in the absence and the presence of potassium cations. On the basis of SAXS data, the low-resolution structure in solution has been reconstructed using ab inito methods.

  5. The effects of soluble Aβ oligomers on neurodegeneration in Alzheimer's disease.

    Brouillette, Jonathan

    2014-01-01

    The neurodegenerative process that defines Alzheimer''s disease (AD) is initially characterized by synaptic alterations followed by synapse loss and ultimately cell death. Decreased synaptic density that precedes neuronal death is the strongest pathological correlate of cognitive deficits observed in AD. Substantial synapse and neuron loss occur early in disease progression in the entorhinal cortex (EC) and the CA1 region of the hippocampus, when memory deficits become clinically detectable. Mounting evidence suggests that soluble amyloid-β (Aβ) oligomers trigger synapse dysfunction both in vitro and in vivo. However, the neurodegenerative effect of Aβ species observed on neuronal culture or organotypic brain slice culture has been more challenging to mimic in animal models. While most of the transgenic mice that overexpress Aβ show abundant amyloid plaque pathology and early synaptic alterations, these models have been less successful in recapitulating the spatiotemporal pattern of cell loss observed in AD. Recently we developed a novel animal model that revealed the neurodegenerative effect of soluble low-molecular-weight Aβ oligomers in vivo. This new approach may now serve to determine the molecular and cellular mechanisms linking soluble Aβ species to neurodegeneration in animals. In light of the low efficiency of AD therapies based on the amyloid cascade hypothesis, a novel framework, the aging factor cascade hypothesis, is proposed in an attempt to integrate the new data and concepts that emerged from recent research to develop disease modifying therapies. PMID:23859546

  6. Identification of chlorinated oligomers formed during anodic oxidation of phenol in the presence of chloride

    Graphical abstract: - Highlights: • By-products from anodic oxidation of phenol in the presence of chloride are investigated. • Chlorinated oligomer formation is demonstrated by LC-QTOF-MS. • They have structures similar to triclosan and polychlorinated dibenzo-p-dioxins. - Abstract: Chlorinated oligomer intermediates formed during the anodic electrochemical oxidation of phenol with a boron-doped diamond electrode were studied at two different concentrations of chloride (5 mM and 50 mM). Under the same ionic strength, with sodium sulfate being the make-up ion, a 10-fold increase in Cl− led to removal rates 10.8, 1.5, and 1.4 times higher for phenol, TOC, and COD, respectively. Mono-, di- and trichlorophenols resulting from electrophilic substitution were the identified by-products. Nevertheless, discrepancies between theoretical and measured TOC values along with gaps in the mass balance of chlorine-containing species indicated the formation of unaccounted-for chlorinated by-products. Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins

  7. Identification of chlorinated oligomers formed during anodic oxidation of phenol in the presence of chloride

    Chen, Linxi; Campo, Pablo; Kupferle, Margaret J., E-mail: margaret.kupferle@uc.edu

    2015-02-11

    Graphical abstract: - Highlights: • By-products from anodic oxidation of phenol in the presence of chloride are investigated. • Chlorinated oligomer formation is demonstrated by LC-QTOF-MS. • They have structures similar to triclosan and polychlorinated dibenzo-p-dioxins. - Abstract: Chlorinated oligomer intermediates formed during the anodic electrochemical oxidation of phenol with a boron-doped diamond electrode were studied at two different concentrations of chloride (5 mM and 50 mM). Under the same ionic strength, with sodium sulfate being the make-up ion, a 10-fold increase in Cl{sup −} led to removal rates 10.8, 1.5, and 1.4 times higher for phenol, TOC, and COD, respectively. Mono-, di- and trichlorophenols resulting from electrophilic substitution were the identified by-products. Nevertheless, discrepancies between theoretical and measured TOC values along with gaps in the mass balance of chlorine-containing species indicated the formation of unaccounted-for chlorinated by-products. Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins.

  8. [Study on chemical constituents of Orobanche coerulescens].

    Zhao, Jun; Yan, Ming; Huang, Yi; He, Wen-yi; Zhao, Yu

    2007-10-01

    Six compounds were isolated and purified from Orobanche coerulescens by extraction and different kinds of column chromatography. The structures were determined on the basis of spectral analysis. The structures were elucidated as D-mannitol(I), beta-sitosterol(II), succinic acid(III), caffeic acid(IV), protocatechuic aldehyde(V) and daucosterol(VI). All compounds are obtained from this plant for the first time. PMID:18300497

  9. Chemical constituents of Croton oligandrum (Euphorbiaceae).

    Abega, Destaing F; Kapche, Deccaux W F G; Ango, Patrick Y; Mapitse, Renameditswe; Yeboah, Samuel O; Ngadjui, Bonaventure T

    2014-01-01

    A new clerodane diterpene derivative named crotonoligaketone was obtained from the stem bark of Croton oligandrum along with eight known compounds including crotonadiol, imbricatadiol, crotonzambefuran B, 7-acetoxytrachiloban-18-oic acid, 3-O-acetylaleuritolic acid, lupeol, beta-sitosterol, and stigmasterol. The structures of the isolated compounds were established on the basis of their spectral data and by comparison with those reported in the literature. PMID:25069155

  10. Crystallization and preliminary crystallographic study of oligomers of the haemolytic lectin CEL-III from the sea cucumber Cucumaria echinata

    Unno, Hideaki; Hisamatsu, Keigo; Nagao, Tomonao; Tateya, Yuki; Matsumoto, Naoki; Goda, Shuichiro; Hatakeyama, Tomomitsu

    2013-01-01

    CEL-III is a Ca2+-dependent haemolytic lectin isolated from the marine invertebrate Cucumaria echinata. This lectin binds to Gal/GalNAc-containing carbohydrate chains on the cell surface and, after conformational changes, oligomerizes to form ion-permeable pores in cell membranes. CEL-III also forms soluble oligomers similar to those formed in cell membranes upon binding of specific carbohydrates in high-pH and high-salt solutions. These soluble and membrane CEL-III oligomers were crystallize...

  11. Steady State and Time-Resolved Fluorescence Dynamics of Triphenylamine Based Oligomers with Phenylene/Thiophene/Furan in Solvents

    ZENG Qi; LIU Ying-Liang; MENG Kang; ZHAO Xiang-Jie; WANG Shu-Feng; GONG Qi-Huang

    2009-01-01

    We investigate the photo-physical properties of a series of triphenylamine-based oligomers by steady-state and picosecond transient fluorescence measurements in solvents. The oligomers are composed alternatively with triph-enylamine and phenylene/thiophene/furan group, bridged by vinyl group (PNB/PNT/PNF). Their fluorescence spectra show bathochromic phenomenon with solvent polarity and viscosity increasing. The fluorescence decays are bi-exponential for PNB and PNT, and tri-exponential for PNF in THF and aniline. The strong viscosity dependence suggests conformational relaxation along the PNF chain after photo excitation.

  12. CRP and Adiponectin and Its Oligomers in the Metabolic Syndrome: Evaluation of New Laboratory-Based Biomarkers

    Devaraj, Sridevi; Swarbrick, Michael M.; Singh, Uma; Adams-Huet, Beverley; Havel, Peter J.; Jialal, Ishwarlal

    2008-01-01

    The metabolic syndrome (MetS) confers an increased risk for diabetes and cardiovascular disease. Although high-sensitive C-reactive protein (hsCRP) concentrations are higher and adiponectin concentrations lower in MetS, there is no reliable biochemical measure that can capture its various features. We evaluated whether hsCRP, adiponectin, or the ratio of adiponectin or its oligomers, especially the high-molecular-weight (HMW) oligomer, to hsCRP predict MetS in 123 subjects with MetS compared ...

  13. On the local anaesthetic action of propolis and some of its constituents.

    Paintz, M; Metzner, J

    1979-12-01

    An ethanolic propolis extract and some constituents isolated from propolis were tested on the cornea of the rabbit and of the mouse for local anaesthetic activity. Total anaesthesia was obtained with the total extract as well as with the compounds 5,7-dihydroxyflavanone (pinocembrin), 5-hydroxy-7-methoxyflavanone (pinostrobin) and with a mixture of caffeic acid esters. Each of these compounds was nearly thrice as potent as the total extract. Propoxypiperocaine which was tested for the purpose of comparison was still efficient in an almost 10-fold lower concentration. When applied subcutaneously, pinocembrin and the mixture of caffeic acid esters produced nearly the same anaesthesia as lidocaine. PMID:545354

  14. Gastroprotective effect of the Mapuche crude drug Araucaria araucana resin and its main constituents.

    Schmeda-Hirschmann, Guillermo; Astudillo, Luis; Rodríguez, Jaime; Theoduloz, Cristina; Yáñez, Tania

    2005-10-01

    The resin from the tree Araucaria araucana (Araucariaceae) has been used since pre-columbian times by the Mapuche amerindians to treat ulcers. The gastroprotective effect of the resin was assessed in the ethanol-HCl-induced gastric ulcer in mice showing a dose-dependent gastroprotective activity at 100, 200 and 300 mg/kg per os. The main three diterpene constituents of the resin, namely imbricatolic acid, 15-hydroxyimbricatolal and 15-acetoxyimbricatolic acid were isolated and evaluated for gastroprotective effect at doses of 50, 100 and 200 mg/kg. A dose-related gastroprotective effect with highly significant activity (Paraucana resin by the Mapuche culture. PMID:15985351

  15. Single molecule experiments emphasize GM1 as a key player of the different cytotoxicity of structurally distinct Aβ1-42 oligomers.

    Calamai, Martino; Evangelisti, Elisa; Cascella, Roberta; Parenti, Niccoló; Cecchi, Cristina; Stefani, Massimo; Pavone, Francesco

    2016-02-01

    It is well established that cytotoxic Aβ oligomers are the key factor that triggers the initial tissue and cell modifications eventually culminating in the development of Alzheimer's disease. Aβ1-42 oligomers display a high degree of polymorphism, and several structurally different oligomers have been described. Amongst them, two types, recently classified as A+ and A-, have been shown to possess similar size but distinct toxic properties, as a consequence of their biophysical and structural differences. Here, we have investigated by means of single molecule tracking the oligomer mobility on the plasma membrane of living neuroblastoma cells and the interaction with the ganglioside GM1, a component of membrane rafts. We have found that A+ and A- oligomers display a similar lateral diffusion on the plasma membrane of living cells. However, only the toxic A+ oligomers appear to interact and alter the mobility of GM1. We have also studied the lateral diffusion of each kind of oligomers in cells depleted or enriched in GM1. We found that the content of GM1 influences the diffusion of both types of oligomer, although the effect of the increased levels of GM1 is higher for the A+ type. Interestingly, the content of GM1 also affects significantly the mobility of GM1 molecules themselves. PMID:26656159

  16. Masses of constituent quarks confined in open bottom hadrons

    Jovanović, V Borka; Jovanović, P; Milošević, J; Ignjatović, S R

    2014-01-01

    We apply color-spin and flavor-spin quark-quark interactions to the meson and baryon constituent quarks, and calculate constituent quark masses, as well as the coupling constants of these interactions. The main goal of this manuscript was to determine constituent quark masses from light and open bottom hadron masses, using the fitting method we have developed and clustering of hadron groups. We use color-spin Fermi-Breit (FB) and flavor-spin Glozman-Riska (GR) hyperfine interaction (HFI) to determine constituent quark masses (especially $b$ quark mass). Our improved fitting procedure of constituent quark masses showed that both interactions we studied represent satisfactory approximations in the case of heavy mesons and baryons with $b$ quark, but on average color-spin (Fermi-Breit) hyperfine interaction yields better fits. Our method also shows the way how the constituent quark masses and the strength of the interaction constants appear in different hadron environments.

  17. Recovery of alkali metal constituents from catalytic coal conversion residues

    Soung, W.Y.

    In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide to precipitate silicon constituents, the pH of the resultant solution is increased, preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  18. Acute effects of dietary constituents on motor skill and cognitive performance in athletes.

    Baker, Lindsay B; Nuccio, Ryan P; Jeukendrup, Asker E

    2014-12-01

    Performance in many sports is at least partially dependent on motor control, coordination, decision-making, and other cognitive tasks. This review summarizes available evidence about the ingestion of selected nutrients or isolated compounds (dietary constituents) and potential acute effects on motor skill and/or cognitive performance in athletes. Dietary constituents discussed include branched-chain amino acids, caffeine, carbohydrate, cocoa flavanols, Gingko biloba, ginseng, guarana, Rhodiola rosea, sage, L-theanine, theobromine, and tyrosine. Although this is not an exhaustive list, these are perhaps the most researched dietary constituents. Caffeine and carbohydrate have the greatest number of published reports supporting their ability to enhance acute motor skill and cognitive performance in athletes. At this time, there is insufficient published evidence to substantiate the use of any other dietary constituents to benefit sports-related motor skill or cognitive performance. The optimal dose and timing of caffeine and carbohydrate intake promoting enhanced motor skill and cognitive performance remain to be identified. Valid, reliable, and sensitive batteries of motor skills and cognitive tests should be developed for use in future efficacy studies. PMID:25400063

  19. Oligomer Formation of Amyloid-β(29-42) from Its Monomers Using the Hamiltonian Replica-Permutation Molecular Dynamics Simulation.

    Itoh, Satoru G; Okumura, Hisashi

    2016-07-14

    Oligomers of amyloid-β peptides (Aβ) are formed during the early stage of the amyloidogenesis process and exhibit neurotoxicity. The oligomer formation process of Aβ and even that of Aβ fragments are still poorly understood, though understanding of these processes is essential for remedying Alzheimer's disease. In order to better understand the oligomerization process of the C-terminal Aβ fragment Aβ(29-42) at the atomic level, we performed the Hamiltonian replica-permutation molecular dynamics simulation with Aβ(29-42) molecules using the explicit water solvent model. We observed that oligomers increased in size through the sequential addition of monomers to the oligomer, rather than through the assembly of small oligomers. Moreover, solvent effects played an important role in this oligomerization process. PMID:27281682

  20. Diverse mechanisms of antidiabetic effects of the different procyanidin oligomer types of two different cinnamon species on db/db mice.

    Chen, Liang; Sun, Peng; Wang, Ting; Chen, Kaixian; Jia, Qi; Wang, Heyao; Li, Yiming

    2012-09-12

    The procyanidin oligomers are thought to be responsible for the antidiabetic activity of cinnamon. To investigate the hypoglycemic effects of different procyanidin oligomer types, the procyanidin oligomer-rich extracts were prepared from two different cinnamon species. Using high-performance liquid chromatography with purified procyanidin oligomers as reference compounds, we found that the Cinnamomum cassia extract (CC-E) and Cinnamomum tamala extract (CT-E) were rich in B- and A-type procyanidin oligomers, respectively. In the experiment, 8-week-old diabetic (db/db) mice were gavaged with CC-E and CT-E (both 200 mg/kg per day) for 4 weeks. Both CC-E and CT-E exhibited antidiabetic effects. Moreover, histopathological studies of the pancreas, liver, and adipose tissue showed that CC-E promoted lipid accumulation in the adipose tissue and liver, whereas CT-E mainly improved the insulin concentration in the blood and pancreas. PMID:22920511

  1. Change in chemical constituents and free radical-scavenging activity during Pear (Pyrus pyrifolia) cultivar fruit development.

    Cho, Jeong-Yong; Lee, Sang-Hyun; Kim, Eun Hee; Yun, Hae Rim; Jeong, Hang Yeon; Lee, Yu Geon; Kim, Wol-Soo; Moon, Jae-Hak

    2015-01-01

    Changes in chemical constituent contents and DPPH radical-scavenging activity in fruits of pear (Pyrus pyrifolia) cultivars during the development were investigated. The fruits of seven cultivars (cv. Niitaka, Chuhwangbae, Wonhwang, Hwangkeumbae, Hwasan, Manpungbae, and Imamuraaki) were collected at 15-day intervals after day 20 of florescence. Vitamins (ascorbic acid and α-tocopherol), arbutin, chlorogenic acid, malaxinic acid, total caffeic acid, total flavonoids, and total phenolics were the highest in immature pear fruit on day 20 after florescence among samples at different growth stages. All of these compounds decreased gradually in the fruit during the development. Immature pear fruit on day 35 or 50 after florescence exhibited higher free radical-scavenging activity than that at other times, although activities were slightly different among cultivars. The chemical constituent contents and free radical-scavenging activity were largely different among immature fruits of the pear cultivars, but small differences were observed when they matured. PMID:25348501

  2. Spin structure of constituent quark and polarized structure of hadrons

    Polarized parton distribution inside a constituent quark is calculated. This structure is universal for all hadrons and the polarized structure of any hadron is a convolution of polarized constituent quark distribution in the hadron with the polarized structure function of the constituent quark. This approach gives very good agreement with the experimental data on polarized proton, neutron, and deuteron. However, in order to assemble the components to build the spin the constituent quark we are forced to include a sizeable orbital angular momentum. (author)

  3. Assignment of hexuronic acid stereochemistry in synthetic heparan sulfate tetrasaccharides with 2-O-sulfo uronic acids using electron detachment dissociation

    Agyekum, Isaac; Patel, Anish B.; Zong, Chengli; Boons, Geert Jan; Amster, I. Jonathan

    2015-01-01

    The present work focuses on the assignment of uronic acid stereochemistry in heparan sulfate (HS) oligomers. The structural elucidation of HS glycosaminoglycans is the subject of considerable importance due to the biological and biomedical significance of this class of carbohydrates. They are highly

  4. Natural wax constituents of a supercritical fluid CO(2) extract from quince (Cydonia oblonga Mill.) pomace.

    Lorenz, Peter; Berger, Melanie; Bertrams, Julia; Wende, Kristian; Wenzel, Kristin; Lindequist, Ulrike; Meyer, Ulrich; Stintzing, Florian C

    2008-05-01

    The chemical constituents of a lipophilic extract from quince (Cydonia oblonga Mill.), obtained by supercritical fluid CO(2) extraction of the dried fruit pomace were investigated. Solvent partition of quince wax with n-hexane or acetone yielded an insoluble (crystalline) and a soluble (oily) fraction. Both fractions were analyzed separately using gas chromatography/mass spectrometry (GC/MS). The insoluble fraction consisted of saturated n-aldehydes, n-alcohols and free n-alkanoic acids of carbon chain lengths between 22 and 32, with carbon chain lengths of 26 and 28 dominating. Also odd-numbered unbranched hydrocarbons, mainly C27, C29 and C31, were detected particularly in the acetone-insoluble fraction (total, 15.8%). By means of vacuum liquid chromatography, triterpenoic acids were separated from the hexane-insoluble matter and identified as a mixture of ursolic, oleanolic and betulinic acids. The major constituents of the hexane-soluble fraction were glycerides of linoleic [Δ(9,12), 18:2] and oleic [Δ(9), 18:1] acids, accompanied by free linoleic, oleic and palmitic acids (C16). Moreover β-sitosterol, Δ(5)-avenasterol as well as trace amounts of other sterols were assigned. Finally the carotenoids phytoene and phytofluene were identified and quantified by UV/vis and high-performance liquid chromatography/MS techniques, yielding 1.0 and 0.3% of the quince wax, respectively. It is anticipated that the complex of lipid constituents from quince wax may exert interesting biological activities, the elucidation of which awaits further studies. PMID:18418588

  5. Leachability of radioactive constituents from uranium mine tailings

    A series of long-term studies were conducted both to examine the leachability of major constituents (acidity, TDS) and radioisotopes from uranium mining/milling tailings and settling pond sludges, and to assess the effect of two treatment methods (solidification and vegetation) on leachate characteristics. Four bench-scale experiments were conducted to examine the leachability of: 1) old tailings and those containing a large portion of (Ba,Ra)SO4 sludges; 2) untreated and solidified (Ba,Ra)SO4 sludges located at the bottom of settling ponds; 3) new tailings that had been vegetated or solidified; and 4) new tailings subject to varying flow rates. A fifth study was conducted to examine the microbiology of Experiments 2 and 3. In addition, the lysimeter solids remaining in the old tailings at the end of Experiment 1 were characterized through chemical and radionuclide analyses and Scanning Electron Microscope-X-ray Emission and Mossbauer Spectroscopy techniques. This report provides an extensive database of temporal variations in leachate characteristics under both normal and accelerated water application rates. It also presents hypotheses of possible leaching mechanisms in the wastes that could explain the observed data, and conceptual model of tailings leaching processes which integrates the results of all the tailings experiments

  6. Estimation of Quercetin, an Anxiolytic Constituent, in Elaeocarpus ganitrus.

    Mohan Pal S. Ishar

    2013-03-01

    Full Text Available Having established quercetin as the anxiolytic constituent of Elaeocarpus ganitrus, it was decided to use it as marker to standardize the plant material. Quercetin was used as an external standard for determining its content in E. ganitrus beads by TLC densitometry. An HPTLC densitometric method has been developed to estimate quercetin inE. ganitrus beads so that plant can be standardized on the basis of its bioactive marker. Two methods were followed for preparing the test samples for determining the quercetin content. Initially, quercetin was determined in the ethanol extract of the plant material. It was also determined in the acid hydrolyzed ethanol extract, in order to free quercetin from its O-glycoside. Quercetin content in the hydrolyzed ethanol extract (0.11% w/w of E. ganitrus beads was found to be about 4 times more than in the ethanol extract prepared by direct method (0.03% w/w. Results showed that quercetin occurs in E. ganitrus beads in the form of glycoside.

  7. Chemical Constituents of the Roots of Anemone altaica Fisch. ex C. A. Mey.

    Zhong-Jie ZOU; Yue-Sheng DONG; Jun-Shan YANG

    2005-01-01

    The roots of Anemone altaica Fisch. ex C. A. Mey. have been used in the treatment of epilepsia,neurasthenia, and arthritis in Chinese folk medicine for a long time. In order to find new and bioactive compounds, the chemical constituents of the roots of A. altaica were investigated and nine compounds were isolated from the EtOH extract of this plant. On the basis of spectroscopic methods, the structures of these compounds were elucidated as 4-(9H-β-carbolin-1-yl)-4-oxo-butyric acid (1), carboxymethyl isoferulate (2), isoferulic acid (3), cirsiumaldehyde (4), 5-hydroxy-4-oxo-pentanoic acid (5), triacontane (6), palmic acid (7), β-sitosterol (8), and daucosterol (9). Among them, 1 and 2 were new compounds, and 3 and 4 were obtained from this genus for the first time.

  8. Antimicrobial chemical constituents from endophytic fungus Phomasp.

    Hidayat Hussain; Siegfried Draeger; Barbara Schulz; Karsten Krohn; Ines Kock; Ahmed Al-Harrasi; Ahmed Al-Rawahi; Ghulam Abbas; Ivan R Green; Afzal Shah; Amin Badshah; Muhammad Saleem

    2014-01-01

    Objective:To evaluate the antimicrobial potential of different extracts of the endophytic fungus Phomasp. and the tentative identification of their active constituents.Methods:The extract and compounds were screened for antimicrobial activity using theAgarWellDiffusionMethod. Four compounds were purified using column chromatography and their structures were assigned using1H and13CNMR spectra,DEPT,2DCOSY,HMQC andHMBC experiments.Results:The ethyl acetate fraction ofPhomasp. showed good antifungal, antibacterial, and algicidal properties.One new dihydrofuran derivative, named phomafuranol(1), together with three known compounds, phomalacton(2),(3R)-5-hydroxymellein(3) and emodin(4) were isolated from the ethyl acetate fraction ofPhomasp.Preliminary studies indicated that phomalacton(2) displayed strong antibacterial, good antifungal and antialgal activities.Similarly(3R)-5-hydroxymellein (3) and emodin(4) showed good antifungal, antibacterial and algicidal properties.Conclusions:Antimicrobial activities of the ethyl acetate fraction of the endophytic fungusPhomasp. and isolated compounds clearly demonstrate thatPhomasp. and its active compounds represent a great potential for the food, cosmetic and pharmaceutical industries.

  9. Constituent-Quark Model and New Particles

    Akers, D

    2003-01-01

    An elementary constituent-quark (CQ) model by Mac Gregor is reviewed with currently published data from light meson spectroscopy. It was previously shown in the CQ model that there existed several mass quanta m = 70 MeV, B = 140 MeV and X = 420 MeV, which were responsible for the quantization of meson yrast levels. The existence of a 70-MeV quantum was postulated by Mac Gregor and was shown to fit the Nambu empirical mass formula mn = (n/2)137me, n a positive integer. It is shown in this paper that recent data of new light mesons fit into the CQ model. With the introduction of the Russell-Saunders coupling scheme into the CQ model, several new meson particles are predicted to exist. The existence of the f0(560) meson is predicted and is shown to fit current experimental data from the Particle Data Group listing. The existence of meson partners or groupings is shown.

  10. Constituents of south Indian vetiver oils.

    Mallavarapu, Gopal Rao; Syamasundar, Kodakandla V; Ramesh, S; Rao, Bhaskaruni R Rajeswara

    2012-02-01

    The essential oils isolated from vetiver [Vetiveria zizanioides (L.) Nash.] roots collected from four locations in south India were analyzed by GC-FID and GC-MS. Eighty constituents, representing 94.5-97.8% of the oils, have been identified. The oils from Bangalore, Hyderabad, Kundapur, and Mettupalayam were rich in sesquiterpenes and oxygenated sesquiterpenes with cedrane, bisabolane, eudesmane, eremophilane, and zizaane skeletons. The main components of the four essential oils were: eudesma-4,6-diene (delta-selinene) + beta-vetispirene (3.9-6.1%), beta-vetivenene (0.9-9.4%), 13-nor-trans-eudesma-4(15),7-dien-11-one + amorph-4-en-10-ol (5.0-6.4%), trans-eudesma-4(15),7-dien-12-ol (vetiselinenol) + (E)-opposita-4(15),7(11)-dien-12-ol (3.7-5.9%), eremophila-1 (10),11-dien-2alpha-ol (nootkatol) + ziza-6(13)-en-12-ol (khusimol) (16.1-19.2%), and eremophila-1(10),7(11)-dien-2alpha-ol (isonootkatol) + (E)-eremophila-1(10),7(11)-12-ol (isovalencenol) (5.6-6.9%). The important compounds that impart the characteristic vetiver odor are: khusimene, delta-selinene, beta-vetivenene, cyclocopacamphan-12-ol (epimers A and B), vetiselinenol, khusimol, isovalencenol, khusimone, alpha-vetivone, and beta-vetivone. The chemical profiles of the oils are comparable to Haitian vetiver oil. PMID:22474964

  11. System for measuring engine exhaust constituents

    This patent describes a system for measuring an automotive engine exhaust constituent. It comprises: a meter for determining the mass of air flowing through the engine and for generating an engine airflow signal corresponding to the airflow; sample handling apparatus; diluent adding means; processor means. This patent also describes a method for using an analyzer to determine the amount of lubricating oil consumed by an automotive engine. It comprises: determining the amount of sulfur dioxide within the room air being drawn into the engine; maintaining a constant total flow comprised of a constant fraction of the engine's exhaust gas and a diluent gas through the analyzer, while: determining the amount of sulfur dioxide contained within the engine's exhaust, determining the amount of sulfur dioxide contained within the engine's exhaust, while operating the engine on room air; determining an efficiency factor for the analyzer; and using the efficiency factor and the concentration of sulfur in the engine oil and the amounts of sulfur dioxide determined in steps a and d to determine the amount of lubrication oil leaving the engine through its exhaust

  12. [Chemical constituents of Sapium sebiferum leaves].

    Gao, Li; Tian, Hua; Lv, Pei-jun; Wang, Jia-ping; Wang, Yi-fen

    2015-04-01

    Chemical constituents of ethyl acetate extract of Sapium sebiferum leaves were isolated and purified by various chromatographic methods, including column chromatographies over silica gel, macroporous adsorption resin, and Sephadex LH-20, as well as preparative TLC and semi preparative HPLC. As a results, 15 compounds were separated from Sapium sebiferum leaves and their structures were examined by spectral analysis including NMR and MS data and identified as( + )-(7R,7'R,7"S,7'"S,8S,8'S,8"S,8'"S)-4", 4"'-dihydroxy-3,3',3",3',5,5'-hexamethoxy-7,9';7',9-diepoxy-4,8";4',8'"-bisoxy-8,8'-dineo-lignan-7",7"',9",9"'-tetraol(1) ,1-(4'- hydroxy-3'-methoxyphenyl)-2-[4"-(3-hydroxypropyl) -2", 6"-dimethoxyphenoxy] propane-1, 3-diol (2), Thero-2, 3-bis-(4-hydroxy-3- methoxypheyl)-3-methoxy-propanol(3) , threo-5-hydroxy-3,7-dimethoxyphenyl propane-8,9-diol (4), boropinol B (5), threo-8S-7-methoxysyringylglycerol(6), 5-hydroxymethylfurfural(7), 5-( methoxy-methyl)-1H-pyrrole-2-carbaldehyde (8), quercetin (9) , kaempferol (10), ethyl gallate(11), coniferaldehyde(12), vanillin(13), 7-hydroxy-6-methoxy-2H-1-henzopyran-2-one(14),and 1-heptacosanol (15). All compounds except for compounds 9-11,14 were separated from this plant for the first time. PMID:26281591

  13. Volatile Constituents of Three Illicium Plants

    Nguyen B. Qinh

    2016-05-01

    Full Text Available The chemical composition of volatiles from the leaves of three different Illicium species has been studied. The essential oils were obtained by hydrodistillation and analyzed by GC (FID and GC-MS. The components by identified by MS libraries and their LRIs. The essential oil contents vary between 0.12% and 0.21% (v/w, calculated on a dry weight basis. Illicium majus J. D. Hooker & Thomson afforded oil whose major constituents were aromadendrene (13.0%, cuparene (8.2%, 1,8-cineole (8.1% and calamenene (7.8%. However, 1,8-cineole (8.4%, linalool (7.7%, (E-nerolidol (7.6% and sabinene (7.1% were the quantitatively significant compounds of the leaf oil of Illicium micranthun Dunn. The leaf oil of Illicium tsaii A. C. Smith comprised mainly of (E-nerolidol (15.5%, β-caryophyllene (8.1%, β-cedrene (6.5%, 1,8-cineole (6.3% and calamenene (6.3%. The chemical composition of the leaf essential oils of these plants from are being reported for the first time.

  14. Mechanisms of hybrid oligomer formation in the pathogenesis of combined Alzheimer's and Parkinson's diseases.

    Igor F Tsigelny

    Full Text Available BACKGROUND: Misfolding and pathological aggregation of neuronal proteins has been proposed to play a critical role in the pathogenesis of neurodegenerative disorders. Alzheimer's disease (AD and Parkinson's disease (PD are frequent neurodegenerative diseases of the aging population. While progressive accumulation of amyloid beta protein (Abeta oligomers has been identified as one of the central toxic events in AD, accumulation of alpha-synuclein (alpha-syn resulting in the formation of oligomers and protofibrils has been linked to PD and Lewy body Disease (LBD. We have recently shown that Abeta promotes alpha-syn aggregation and toxic conversion in vivo, suggesting that abnormal interactions between misfolded proteins might contribute to disease pathogenesis. However the molecular characteristics and consequences of these interactions are not completely clear. METHODOLOGY/PRINCIPAL FINDINGS: In order to understand the molecular mechanisms involved in potential Abeta/alpha-syn interactions, immunoblot, molecular modeling, and in vitro studies with alpha-syn and Abeta were performed. We showed in vivo in the brains of patients with AD/PD and in transgenic mice, Abeta and alpha-synuclein co-immunoprecipitate and form complexes. Molecular modeling and simulations showed that Abeta binds alpha-syn monomers, homodimers, and trimers, forming hybrid ring-like pentamers. Interactions occurred between the N-terminus of Abeta and the N-terminus and C-terminus of alpha-syn. Interacting alpha-syn and Abeta dimers that dock on the membrane incorporated additional alpha-syn molecules, leading to the formation of more stable pentamers and hexamers that adopt a ring-like structure. Consistent with the simulations, under in vitro cell-free conditions, Abeta interacted with alpha-syn, forming hybrid pore-like oligomers. Moreover, cells expressing alpha-syn and treated with Abeta displayed increased current amplitudes and calcium influx consistent with the

  15. Phytochemical investigation of Gynura bicolor leaves and cytotoxicity evaluation of the chemical constituents against HCT 116 cells.

    Teoh, Wuen Yew; Tan, Hooi Poay; Ling, Sui Kiong; Abdul Wahab, Norhanom; Sim, Kae Shin

    2016-01-01

    Gynura bicolor (Compositae) is a popular vegetable in Asia and believed to confer a wide range of benefits including anti-cancer. Our previous findings showed that the ethyl acetate extract of G. bicolor possessed cytotoxicity and induced apoptotic and necrotic cell death in human colon carcinoma cells (HCT 116). A combination of column chromatography had been used to purify chemical constituents from the ethyl acetate and water extract of G. bicolor leaves. Eight chemical constituents 5-p-trans-coumaroylquinic acid (I), 4-hydroxybenzoic acid (II), rutin (III), kampferol-3-O-rutinoside (IV), 3,5-dicaffeoylquinic acid (V), kampferol-3-O-glucoside (VI), guanosine (VII) and chlorogenic acid (VIII) were isolated from G. bicolor grown in Malaysia. To our best knowledge, all chemical constituents were isolated for the first time from G. bicolor leaves except rutin (III). 3,5-dicaffeoylquinic acid (V), guanosine (VII) and chlorogenic acid (VIII) demonstrated selective cytotoxicity (selective index>3) against HCT 116 cancer cells compared to CCD-18Co human normal colon cells. PMID:25738869

  16. Bioactive natural constituents from food sources-potential use in hypertension prevention and treatment.

    Huang, Wu-Yang; Davidge, Sandra T; Wu, Jianping

    2013-01-01

    Prevention and management of hypertension are the major public health challenges worldwide. Uncontrolled high blood pressure may lead to a shortened life expectancy and a higher morbidity due to a high risk of cardiovascular complications such as coronary heart disease (which leads to heart attack) and stroke, congestive heart failure, heart rhythm irregularities, and kidney failure etc. In recent years, it has been recognized that many dietary constituents may contribute to human cardiovascular health. There has been an increased focus on identifying these natural components of foods, describing their physiological activities and mechanisms of actions. Grain, vegetables, fruits, milk, cheese, meat, chicken, egg, fish, soybean, tea, wine, mushrooms, and lactic acid bacteria are various food sources with potential antihypertensive effects. Their main bioactive constituents include angiotensin I-converting enzyme (ACE) inhibitory peptides, vitamins C and E, flavonoids, flavanols, cathecins, anthocyanins, phenolic acids, polyphenols, tannins, resveratrol, polysaccharides, fiber, saponin, sterols, as well as K, Ca, and P. They may reduce blood pressure by different mechanisms, such as ACE inhibition effect, antioxidant, vasodilatory, opiate-like, Ca(2+) channel blocking, and chymase inhibitory activities. These functional foods may provide new therapeutic applications for hypertension prevention and treatment, and contribute to a healthy cardiovascular population. The present review summarizes the antihypertensive food sources and their bioactive constituents, as well as physiological mechanisms of dietary products, especially focusing on ACE inhibitory activity. PMID:23627503

  17. Templated Synthesis of Peptide Nucleic Acids via Sequence-Selective Base-Filling Reactions

    Heemstra, Jennifer M.; Liu, David Ruchien

    2009-01-01

    The templated synthesis of nucleic acids has previously been achieved through the backbone ligation of preformed nucleotide monomers or oligomers. In contrast, here we demonstrate templated nucleic acid synthesis using a base-filling approach in which individual bases are added to abasic sites of a peptide nucleic acid (PNA). Because nucleobase substrates in this approach are not self-reactive, a base-filling approach may reduce the formation of nontemplated reaction products. Using either re...

  18. Tuning of the excited state properties of phenylenevinylene oligomers : A time-dependent density functional theory study

    Grozema, FC; Telesca, R; Snijders, JG; Siebbeles, LDA

    2003-01-01

    This paper discusses a time-dependent density functional theory study of the effect of molecular structure on the excited state polarizability of conjugated molecules. A short phenylenevinylene oligomer containing three phenyl rings (PV2, distyryl benzene) is taken as a model system. Introduction of

  19. Lifetimes of organic photovoltaics: Design and synthesis of single oligomer molecules in order to study chemical degradation mechanisms

    Alstrup, J.; Norrman, K.; Jørgensen, M.; Krebs, Frederik C

    2006-01-01

    Degradation mechanisms in organic and polymer photovoltaics are addressed through the study of an organic photovoltaic molecule based on a single phenylene-vinylene-type oligomer molecule. The synthesis of such a model compound with different end-groups is presented that allows for assignment of ...

  20. Charge-carrier selective electrodes for organic bulk heterojunction solar cell by contact-printed siloxane oligomers

    ‘Smart’ (or selective) electrode for charge carriers, both electrons and holes, in organic bulk-heterojunction (BHJ) solar cells using insertion layers made of hydrophobically-recovered and contact-printed siloxane oligomers between electrodes and active material has been demonstrated. The siloxane oligomer insertion layer has been formed at a given interface simply by conformally-contacting a cured slab of polydimethylsiloxane stamp for less than 100 s. All the devices, either siloxane oligomer printed at one interface only or printed at both interfaces, showed efficiency enhancement when compared to non-printed ones. The possible mechanism that is responsible for the observed efficiency enhancement has been discussed based on the point of optimum symmetry and photocurrent analysis. Besides its simplicity and large-area applicability, the demonstrated contact-printing technique does not involve any vacuum or wet processing steps and thus can be very useful for the roll-based, continuous production scheme for organic BHJ solar cells. - Highlights: • Carrier-selective insertion layer in organic bulk heterojunction solar cells • Simple contact-printing of siloxane oligomers improves cell efficiency. • Printed siloxane layer reduces carrier recombination at electrode surfaces. • Siloxane insertion layer works equally well at both electrode surfaces. • Patterned PDMS stamp shortens the printing time within 100 s

  1. Charge-carrier selective electrodes for organic bulk heterojunction solar cell by contact-printed siloxane oligomers

    Hwang, Hyun-Sik; Khang, Dahl-Young, E-mail: dykhang@yonsei.ac.kr

    2015-08-31

    ‘Smart’ (or selective) electrode for charge carriers, both electrons and holes, in organic bulk-heterojunction (BHJ) solar cells using insertion layers made of hydrophobically-recovered and contact-printed siloxane oligomers between electrodes and active material has been demonstrated. The siloxane oligomer insertion layer has been formed at a given interface simply by conformally-contacting a cured slab of polydimethylsiloxane stamp for less than 100 s. All the devices, either siloxane oligomer printed at one interface only or printed at both interfaces, showed efficiency enhancement when compared to non-printed ones. The possible mechanism that is responsible for the observed efficiency enhancement has been discussed based on the point of optimum symmetry and photocurrent analysis. Besides its simplicity and large-area applicability, the demonstrated contact-printing technique does not involve any vacuum or wet processing steps and thus can be very useful for the roll-based, continuous production scheme for organic BHJ solar cells. - Highlights: • Carrier-selective insertion layer in organic bulk heterojunction solar cells • Simple contact-printing of siloxane oligomers improves cell efficiency. • Printed siloxane layer reduces carrier recombination at electrode surfaces. • Siloxane insertion layer works equally well at both electrode surfaces. • Patterned PDMS stamp shortens the printing time within 100 s.

  2. Identification and quantification of oligomers as potential migrants in plastics food contact materials with a focus in polycondensates - A review

    M. Hoppe; P. de Voogt; R. Franz

    2016-01-01

    Background: Over the last years the variety of food and beverage packaging has increased with the development of new plastic materials and (co)polymer modifications. Oligomers which are always present in polymers evoke attention as potential migrants, from a qualitatively and quantitatively viewpoin

  3. Amyloid-β Oligomers May Impair SNARE-Mediated Exocytosis by Direct Binding to Syntaxin 1a

    Yoosoo Yang

    2015-08-01

    Full Text Available Alzheimer’s disease (AD is closely associated with synaptic dysfunction, and thus current treatments often aim to stimulate neurotransmission to improve cognitive impairment. Whereas the formation of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE complex is essential for synaptic transmission, the correlation between SNAREs and AD neuropathology is unknown. Here, we report that intracellular amyloid-β (Aβ oligomers directly inhibit SNARE-mediated exocytosis by impairing SNARE complex formation. We observe abnormal reduction of SNARE complex levels in the brains of APP/PS1 transgenic (TG mice compared to age-matched wild-types. We demonstrate that Aβ oligomers block SNARE complex assembly through the direct interaction with a target membrane (t-SNARE syntaxin 1a in vitro. Furthermore, the results of the in vitro single-vesicle content-mixing assay reveal that Aβ oligomers inhibit SNARE-mediated fusion pores. Thus, our study identifies a potential molecular mechanism by which intracellular Aβ oligomers hamper SNARE-mediated exocytosis, likely leading to AD-associated synaptic dysfunctions.

  4. The PI3K-Akt-mTOR pathway regulates Aβ oligomer induced neuronal cell cycle events

    Herrup Karl

    2009-03-01

    Full Text Available Abstract Accumulating evidence suggests that neurons prone to degeneration in Alzheimer's Disease (AD exhibit evidence of re-entry into an aberrant mitotic cell cycle. Our laboratory recently demonstrated that, in a genomic amyloid precursor protein (APP mouse model of AD (R1.40, neuronal cell cycle events (CCEs occur in the absence of beta-amyloid (Aβ deposition and are still dependent upon the amyloidogenic processing of the amyloid precursor protein (APP. These data suggested that soluble Aβ species might play a direct role in the induction of neuronal CCEs. Here, we show that exposure of non-transgenic primary cortical neurons to Aβ oligomers, but not monomers or fibrils, results in the retraction of neuronal processes, and induction of CCEs in a concentration dependent manner. Retraction of neuronal processes correlated with the induction of CCEs and the Aβ monomer or Aβ fibrils showed only minimal effects. In addition, we provide evidence that induction of neuronal CCEs are autonomous to primary neurons cultured from the R1.40 mice. Finally, our results also demonstrate that Aβ oligomer treated neurons exhibit elevated levels of activated Akt and mTOR (mammalian Target Of Rapamycin and that PI3K, Akt or mTOR inhibitors blocked Aβ oligomer-induced neuronal CCEs. Taken together, these results demonstrate that Aβ oligomer-based induction of neuronal CCEs involve the PI3K-Akt-mTOR pathway.

  5. Chemical constituents of Ochroma lagopus Swartz

    Phytochemical investigation of the heartwood of Ochroma lagopus Swartz, led to the isolation of coumarins scopoletin and cleomiscosin A; lignans boehmenan and secoisolariciresinoyl diferulate, besides β-sitosterol, stigmasterol and a mixture of fatty acids and esters. Carbon-13 and proton NMR were used to identify and characterize their molecular structure. Infrared spectra and mass spectra were also utilized. (author)

  6. Chemical constituents of Arrabidaea samydoides (Bignoniaceae)

    Chemical investigation of Arrabidaea samydoides resulted in the isolation of the flavone chrysin; five triterpenes: lupeol, ursolic acid, 3β,16α-dihydroxy-urs-12-ene, uvaol, and erythrodiol; and two sterols: sitosterol and stigmasterol. The structures of these compounds were established by spectroscopic analysis. This paper deal with the first phytochemical study of Arrabidaea samydoides. (author)

  7. 40 CFR 264.342 - Principal organic hazardous constituents (POHCs).

    2010-07-01

    ... (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE...) Principal Organic Hazardous Constituents (POHCs) in the waste feed must be treated to the extent required by... permit, from among those constituents listed in part 261, appendix VIII of this chapter, for each...

  8. Glueball-glueball potential in a constituent gluon model

    da Silva, M L L; Vasconcellos, C A Z

    2012-01-01

    In this work we use a mapping technique to derive in the context of a constituent gluon model an effective Hamiltonian that involves explicit gluon degrees of freedom. We study glueballs with two gluons using the Fock-Tani formalism. In the present work we calculate the glueball-glueball potential, in the context of the constituent gluon model, with gluon interchange.

  9. Template Directed Oligomer Ligation in Eutectic Phases in Water-Ice

    Dörr, Mark; Löffler, Philipp M. G.; Wieczorek, Rafal;

    2011-01-01

    Eutectic phases of water-ice are protective micro-environments for the non-enzymatic, metal ion mediated polymerization of imidazole-activated ribonucleotides (Monnard 2008). Polymers of up to 30-mer lengths can herein be achieved. Even longer polymers can be obtained by adding activated monomers...... or short oligomers to a solution over several freeze-thawing cycles. The final length is determined by the balancing rates of condensation and hydrolysis. A certain critical length of about 25 to 30 oligonucleotides is required to show catalytic activity (Scott 1995). This length can be much quicker....... (a) Reaction scheme of the condensation reaction of two oligoribonucleotides : The leaving group in this example is imidazole. (b) Illustration of a possible spatial arrangement of a template (15nt) directed ligation. The 7-mer is activated with imidazole at the 5' phosphate (apical moiety in the...

  10. Preparation and Property of Bisphenol A Bis(diphenyl phosphate) Oligomer

    LI Bing-hai; OU Yu-xiang; XIN Fei

    2007-01-01

    Bisphenol A bis(diphenyl phosphate) oligomer(BDP) is prepared successfully from the reactants consisting of phosphorus oxychloride (POCl3), bisphenol A and phenol with a Friedel-Crafts catalyst. The resultant products were examined with thermo-gravimetric analysis (TGA) and high performance liquid chromatography(HPLC). Thermogravimetry data shows that BDP decomposes at 375℃ when 5% weight lost. Experiments results show that catalyst is preferably AlCl3 and the amount of it is preferably 1% relative to bisphenol A by mole. POCl3/bisphenol A mole ratio is preferably about 5∶1 to 6∶1. Experiments unclosed that a seal apparatus is very important to the properties of product.

  11. Membrane-mediated interactions and the dynamics of dynamin oligomers on membrane tubes

    Shlomovitz, R; Gov, N S [Department of Chemical Physics, Weizmann Institute of Science, PO Box 26, Rehovot, Israel 76100 (Israel); Roux, A, E-mail: nir.gov@weizmann.ac.il [Department of Biochemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva (Switzerland)

    2011-06-15

    Dynamin is a protein that plays a key role in the transport and recycling of membrane tubes and vesicles within a living cell. This protein adsorbs from solution to PIP{sub 2}-containing membranes, and on these tubes it forms curved oligomers that condense into tight helical domains of uniform radius. The dynamics of this process is treated here in terms of the linear stability of a continuum model, whereby membrane-mediated interactions are shown to drive the spontaneous nucleation of condensed dynamin domains. We furthermore show that the deformation of the membrane outside the dynamin domains induces an energy barrier that can hinder the full coalescence of neighboring growing domains. We compare these calculations to experimental observations on dynamin dynamics in vitro.

  12. On the effect of electron correlation on the static second hyperpolarizability of π conjugated oligomer chains.

    Limacher, Peter A; Li, Qingxu; Lüthi, Hans P

    2011-07-01

    In this article, we report on the ab initio calculation of the static longitudinal second hyperpolarizability (γ) of π conjugated unsaturated oligomer chains using polyacetylene and polyyne as model compounds. The common observation is that the electron correlation enhances γ in these systems. The present study reveals that for extended chain lengths the opposite appears to be true: Electron correlation may have a damping effect on this property. For double-zeta basis sets, a negative contribution from electron correlation to γ is found within the range of chain lengths investigated. For triple-zeta basis sets, the same behavior must be anticipated at larger chain lengths based on extrapolation schemes. The analysis of the excitation energies and transition moments shows that transition moments between excited states as predicted by the Hartree-Fock and coupled cluster methods have a different response to chain length extension. There also are indications that higher order correlation effects will enhance γ. PMID:21744892

  13. Temperature, Molecular Weight, and Concentration Dependences of Thermal Diffusion for Ethylene Glycol Oligomers and Crown Ethers

    Maeda, Kousaku; Kita, Rio; Shinyashiki, Naoki; Yagihara, Shin

    The Soret coefficient ST of ethylene glycol oligomers (EGOs) and crown ethers (CEs) in water were obtained by thermal diffusion forced Rayleigh scattering by changing the temperature, molecular weight, and concentration. The effect of a hydroxyl group on the EGOs and the effect of the cyclic structure of CEs on the thermal diffusion were determined systematically by changing the molecular weights of the EGOs and CEs. For dilute aqueous solutions, EGOs and CEs, except EG, show positive ST values that decrease with increasing temperature, which is similar to the results of previous studies on mixtures of water and organic solvents. The temperature dependence of ST changes its behavior from negative to positive with decreasing number of repeating units of EGOs. This behavior is related to the increase in the number density of the hydroxyl group. The ST values of EG show two different concentration regions, namely, the low concentration (0-2 wt %) and high concentration (2-100 wt %) regions.

  14. γ-ray degradation of chitosan to prepare water-soluble oligomers

    Water-soluble chitosan oligomers with different molecular weight were prepared by a γ-ray degradation method. Effects of irradiation conditions on the chitosan degradation, molecular weight of the irradiated chitosan and yield of the water-soluble products were studied. Gd value of the chitosan radiation degradiation was calculated, and mechanisms of the degradation were discussed. Gel permeation chromatography, Fourier transform infrared spectroscopy and ultraviolet-visible spectrometry (UV-VIS) were applied to characterized and analyzed the degradation products. The results indicated that molecular weight of the degraded chitosan decreased remarkably and its chemical structure changed. It was considered that OH radical is vital to the radiation degradation of chitosan. (authors)

  15. Resonant stimulation of Raman scattering from single-crystal thiophene/phenylene co-oligomers

    Amplified Raman scattering was observed from single crystals of thiophene/phenylene co-oligomers (TPCOs). Under ns-pulsed excitation, the TPCO crystals exhibited amplified spontaneous emission (ASE) at resonant absorption wavelengths. With increasing excitation wavelength to the 0-0 absorption edge, the stimulated resonant Raman peaks appeared both in the 0-1 and 0-2 ASE band regions. When the excitation wavelength coincided with the 0-1 ASE band energy, the Raman peaks selectively appeared in the 0-2 ASE band. Such unusual enhancement of the 0-2 Raman scattering was ascribed to resonant stimulation via vibronic coupling with electronic transitions in the uniaxially oriented TPCO molecules

  16. Synergistic effects of atmospheric pressure plasma-emitted components on DNA oligomers: a Raman spectroscopic study.

    Edengeiser, Eugen; Lackmann, Jan-Wilm; Bründermann, Erik; Schneider, Simon; Benedikt, Jan; Bandow, Julia E; Havenith, Martina

    2015-11-01

    Cold atmospheric-pressure plasmas have become of increasing importance in sterilization processes especially with the growing prevalence of multi-resistant bacteria. Albeit the potential for technological application is obvious, much less is known about the molecular mechanisms underlying bacterial inactivation. X-jet technology separates plasma-generated reactive particles and photons, thus allowing the investigation of their individual and joint effects on DNA. Raman spectroscopy shows that particles and photons cause different modifications in DNA single and double strands. The treatment with the combination of particles and photons does not only result in cumulative, but in synergistic effects. Profilometry confirms that etching is a minor contributor to the observed DNA damage in vitro. Schematics of DNA oligomer treatment with cold atmospheric-pressure plasma. PMID:25656637

  17. Oligomer stability of Amyloid- β (A β) 25-35: A Dissipative Particle Dynamics study

    Pivkin, Igor; Peter, Emanuel

    Alzheimer's disease is strongly associated with an accumulation of Amyloid- β (A β) peptide plaques in the human brain. A β is a 43 residues long intrinsically disordered peptide and has a strong tendency to form aggregates. Evidence accumulates that A β acts toxic to the neurons in the brain through the formation of small soluble oligomers. A β 25-35 is the smallest fragment of A β which still retains its toxicity and its ability to form extended fibrils. In this talk we will present the results from simulations of aggregation of up to 100 A β 25-35 peptides using a novel polarizable coarse-grained protein model in combination with Dissipative Particle Dynamics.

  18. Oligomer Formation of Toxic and Functional Amyloid Peptides Studied with Atomistic Simulations.

    Carballo-Pacheco, Martín; Ismail, Ahmed E; Strodel, Birgit

    2015-07-30

    Amyloids are associated with diseases, including Alzheimer's, as well as functional roles such as storage of peptide hormones. It is still unclear what differences exist between aberrant and functional amyloids. However, it is known that soluble oligomers formed during amyloid aggregation are more toxic than the final fibrils. Here, we perform molecular dynamics simulations to study the aggregation of the amyloid-β peptide Aβ25-35, associated with Alzheimer's disease, and two functional amyloid-forming tachykinin peptides: kassinin and neuromedin K. Although the three peptides have similar primary sequences, tachykinin peptides, in contrast to Aβ25-35, form nontoxic amyloids. Our simulations reveal that the charge of the C-terminus is essential to controlling the aggregation process. In particular, when the kassinin C-terminus is not amidated, the aggregation kinetics decreases considerably. In addition, we observe that the monomeric peptides in extended conformations aggregate faster than those in collapsed hairpin-like conformations. PMID:26130191

  19. Synthesis of Kappa-carrageenan oligomers via synergistic action of gamma radiation and hydrogen peroxide

    In this study, the synthesis of k-carrageenan oligometers with the simultaneous action of gamma radiation and hydrogen peroxide was carried out. Effects on molecular weight and structure of k-carrageenan were assessed using GPC, UV-VIS and FT-IR. Radiation degradation yield (G(s)) and reaction rate constants (k) based on Mn values were also determined. The results showed that k-carrageenan oligomers with Mw of less than 10 kDa can be prepared easily at low doses (2.5-5 kGy) in the presence of low concentrations of hydrogen peroxide (0.25-0.5%). The G(s)) and k values increased significantly with the presence of H2O2. Structural changes in k-carrageenan treated by the degradation agents were accompanied by appearance of UV peak at 260 nm and characteristic FT-IR band at 1728 cm-1. (Author)

  20. Catalytic production of biofuels (butene oligomers) and biochemicals (tetrahydrofurfuryl alcohol) from corn stover.

    Byun, Jaewon; Han, Jeehoon

    2016-07-01

    A strategy is presented that produces liquid hydrocarbon fuels (butene oligomers (BO)) from cellulose (C6) fraction and commodity chemicals (tetrahydrofurfuryl alcohol (THFA)) from hemicellulose (C5) of corn stover based on catalytic conversion technologies using 2-sec-butylphenol (SBP) solvents. This strategy integrates the conversion subsystems based on experimental studies and separation subsystems for recovery of biomass derivatives and SBP solvents. Moreover, a heat exchanger network is designed to reduce total heating requirements to the lowest level, which is satisfied from combustion of biomass residues (lignin and humins). Based on the strategy, this work offers two possible process designs (design A: generating electricity internally vs. design B: purchasing electricity externally), and performs an economic feasibility study for both the designs based on a comparison of the minimum selling price (MSP) of THFA. This strategy with the design B leads to a better MSP of $1.93 per kg THFA. PMID:27030955