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Sample records for aldehyde functional groups

  1. Aldehyde Recognition and Discrimination by Mammalian Odorant Receptors via Functional Group-Specific Hydration Chemistry

    PubMed Central

    2015-01-01

    The mammalian odorant receptors (ORs) form a chemical-detecting interface between the atmosphere and the nervous system. This large gene family is composed of hundreds of membrane proteins predicted to form as many unique small molecule binding niches within their G-protein coupled receptor (GPCR) framework, but very little is known about the molecular recognition strategies they use to bind and discriminate between small molecule odorants. Using rationally designed synthetic analogs of a typical aliphatic aldehyde, we report evidence that among the ORs showing specificity for the aldehyde functional group, a significant percentage detect the aldehyde through its ability to react with water to form a 1,1-geminal (gem)-diol. Evidence is presented indicating that the rat OR-I7, an often-studied and modeled OR known to require the aldehyde function of octanal for activation, is likely one of the gem-diol activated receptors. A homology model based on an activated GPCR X-ray structure provides a structural hypothesis for activation of OR-I7 by the gem-diol of octanal. PMID:25181321

  2. Biomass Vanillin-Derived Polymeric Microspheres Containing Functional Aldehyde Groups: Preparation, Characterization, and Application as Adsorbent.

    PubMed

    Zhang, Huanyu; Yong, Xueyong; Zhou, Jinyong; Deng, Jianping; Wu, Youping

    2016-02-03

    The contribution reports the first polymeric microspheres derived from a biomass, vanillin. It reacted with methacryloyl chloride, providing monomer vanillin methacrylate (VMA), which underwent suspension polymerization in aqueous media and yielded microspheres in high yield (>90 wt %). By controlling the N2 bubbling mode and by optimizing the cosolvent for dissolving the solid monomer, the microspheres were endowed with surface pores, demonstrated by SEM images and mercury intrusion porosimetry measurement. Taking advantage of the reactive aldehyde groups, the microspheres further reacted with glycine, thereby leading to a novel type of Schiff-base chelating material. The functionalized microspheres demonstrated remarkable adsorption toward Cu(2+) (maximum, 135 mg/g) which was taken as representative for metal ions. The present study provides an unprecedented class of biobased polymeric microspheres showing large potentials as adsorbents in wastewater treatment. Also importantly, the reactive aldehyde groups may enable the microspheres to be used as novel materials for immobilizing biomacromolecules, e.g. enzymes.

  3. Microsphere coated substrate containing reactive aldehyde groups

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Richard C. K. (Inventor)

    1984-01-01

    A synthetic organic resin is coated with a continuous layer of contiguous, tangential, individual microspheres having a uniform diameter preferably between 100 Angstroms and 2000 Angstroms. The microspheres are an addition polymerized polymer of an unsaturated aldehyde containing 4 to 20 carbon atoms and are covalently bonded to the substrate by means of high energy radiation grafting. The microspheres contain reactive aldehyde groups and can form conjugates with proteins such as enzymes or other aldehyde reactive materials.

  4. Directing-group-assisted copper-catalyzed oxidative esterification of phenols with aldehydes.

    PubMed

    Zheng, Yong; Song, Wei-Bin; Xuan, Li-Jiang

    2015-11-28

    A directing-group-assisted copper-catalyzed oxidative esterification of phenols with aldehydes using TBHP as an oxidant was described. This methodology which showed the advantages of base, ligand free, short routes and functional group tolerance could be used as an alternative protocol for the classical esterification reactions.

  5. Does acute exposure to aldehydes impair pulmonary function and structure?

    PubMed

    Abreu, Mariana de; Neto, Alcendino Cândido; Carvalho, Giovanna; Casquillo, Natalia Vasconcelos; Carvalho, Niedja; Okuro, Renata; Ribeiro, Gabriel C Motta; Machado, Mariana; Cardozo, Aléxia; Silva, Aline Santos E; Barboza, Thiago; Vasconcellos, Luiz Ricardo; Rodrigues, Danielle Araujo; Camilo, Luciana; Carneiro, Leticia de A M; Jandre, Frederico; Pino, Alexandre V; Giannella-Neto, Antonio; Zin, Walter A; Corrêa, Leonardo Holanda Travassos; Souza, Marcio Nogueira de; Carvalho, Alysson R

    2016-07-15

    Mixtures of anhydrous ethyl alcohol and gasoline substituted for pure gasoline as a fuel in many Brazilian vehicles. Consequently, the concentrations of volatile organic compounds (VOCs) such as ketones, other organic compounds, and particularly aldehydes increased in many Brazilian cities. The current study aims to investigate whether formaldehyde, acetaldehyde, or mixtures of both impair lung function, morphology, inflammatory and redox responses at environmentally relevant concentrations. For such purpose, C57BL/6 mice were exposed to either medical compressed air or to 4 different mixtures of formaldehyde and acetaldehyde. Eight hours later animals were anesthetized, paralyzed and lung mechanics and morphology, inflammatory cells and IL-1β, KC, TNF-α, IL-6, CCL2, MCP-1 contents, superoxide dismutase and catalalase activities were determined. The extra pulmonary respiratory tract was also analyzed. No differences could be detected between any exposed and control groups. In conclusion, no morpho-functional alterations were detected in exposed mice in relation to the control group.

  6. Functional Group Analysis.

    ERIC Educational Resources Information Center

    Smith, Walter T., Jr.; Patterson, John M.

    1984-01-01

    Literature on analytical methods related to the functional groups of 17 chemical compounds is reviewed. These compounds include acids, acid azides, alcohols, aldehydes, ketones, amino acids, aromatic hydrocarbons, carbodiimides, carbohydrates, ethers, nitro compounds, nitrosamines, organometallic compounds, peroxides, phenols, silicon compounds,…

  7. Polyetherurethane oligomers with aldehyde groups as additives for lubricating oils

    SciTech Connect

    Nikolaev, V.N.; Abramov, E.G.; Tenyushev, A.I.

    1995-01-01

    Polyetherurethane oligomers with aldehyde groups, which we synthesized from polyoxypropylene diols (molecular weight 500, 1000, 1500, 2000, or 3000) with toluene diisocyanate and salicylaldehyde, are of interest as additives for lubricating oils. The effects of these oligomers on the service properties and physicochemical characteristics of lubricating oils were investigated by methods prreviously described. As the lube base stocks we used castor oil, a polyoxypropylene diol and a polyethoxysiloxane. The oligomers are readily soluble in organic solvents and in the lube base stocks, and their solutions are stable during storage and use. We found that the optimal concentration of oligomers is 5%, providing the best lubricating properties, in particular the best antiwear properties.

  8. Functional group analysis

    SciTech Connect

    Smith, W.T. Jr.; Patterson, J.M.

    1986-04-01

    Analytical methods for functional group analysis are reviewed. Literature reviewed is from the period of December 1983 through November 1985 and presents methods for determining the following compounds: acids, acid halides, active hydrogen, alcohols, aldehydes, ketones, amides, amines, amino acids, anhydrides, aromatic hydrocarbons, azo compounds, carbohydrates, chloramines, esters, ethers, halogen compounds, hydrazines, isothiocyanates, nitro compounds, nitroso compounds, organometallic compounds, oxiranes, peroxides, phenols, phosphorus compounds, quinones, silicon compounds, sulfates, sulfonyl chlorides, thioamides, thiols, and thiosemicarbazones. 150 references.

  9. Quantification of aldehyde terminated heparin by SEC-MALLS-UV for the surface functionalization of polycaprolactone biomaterials.

    PubMed

    Irvine, Scott A; Steele, Terry W J; Bhuthalingam, Ramya; Li, Min; Boujday, Souhir; Prawirasatya, Melissa; Neoh, Koon Gee; Boey, Freddy Yin Chiang; Venkatraman, Subbu S

    2015-08-01

    A straight forward strategy of heparin surface grafting employs a terminal reactive-aldehyde group introduced through nitrous acid depolymerization. An advanced method that allows simultaneously monitoring of both heparin molar mass and monomer/aldehyde ratio by size exclusion chromatography, multi-angle laser light scattering and UV-absorbance (SEC-MALLS-UV) has been developed to improve upon heparin surface grafting. Advancements over older methods allow quantitative characterization by direct (aldehyde absorbance) and indirect (Schiff-based absorbance) evaluation of terminal functional aldehydes. The indirect quantitation of functional aldehydes through labeling with aniline (and the formation of a Schiff-base) allows independent quantitation of both polymer mass and terminal functional groups with the applicable UV mass extinction coefficients determined. The protocol was subsequently used to synthesize an optimized heparin-aldehyde that had minimal polydispersity (PDI<2) and high reaction yields (yield >60% by mass). The 8 kDa weight averaged molar mass heparin-aldehyde was then grafted on polycaprolactone (PCL), a common implant material. This optimized heparin-aldehyde retained its antithrombin activity, assessed in freshly drawn blood or surface immobilized on PCL films. Anticoagulant activity was equal to or better than the 24 kDa unmodified heparin it was fragmented from.

  10. Functional Group Analysis.

    ERIC Educational Resources Information Center

    Smith, Walter T., Jr.; Patterson, John M.

    1980-01-01

    Discusses analytical methods selected from current research articles. Groups information by topics of general interest, including acids, aldehydes and ketones, nitro compounds, phenols, and thiols. Cites 97 references. (CS)

  11. Introduction of aldehyde vs. carboxylic groups to cellulose nanofibers using laccase/TEMPO mediated oxidation.

    PubMed

    Jaušovec, Darja; Vogrinčič, Robert; Kokol, Vanja

    2015-02-13

    The chemo-enzymatic modification of cellulose nanofibers (CNFs) using laccase as biocatalysts and TEMPO or 4-Amino-TEMPO as mediators under mild aqueous conditions (pH 5, 30 °C) has been investigated to introduce surface active aldehyde groups. 4-Amino TEMPO turned out to be kinetically 0.5-times (50%) more active mediator, resulting to oxoammonium cation intermediacy generated and its in situ regeneration during the modification of CNFs. Accordingly, beside of around 750 mmol/kg terminally-located aldehydes, originated during CNFs isolation, the reaction resulted to about 140% increase of C6-located aldehydes at optimal conditions, without reducing CNFs crystallinity. While only the C6-aldehydes were wholly transformed into the carboxyls after additional post-treatment using NaOH according to the Cannizzaro reaction, the post-oxidation with air-oxygen in EtOH/water medium or NaClO2 resulted to no- or very small amounts of carboxyls created, respectively, at a simultaneous loss of all C6- and some terminal-aldehydes in the latter due to the formation of highly-resistant hemiacetal covalent linkages with available cellulose hydroxyls. The results indicated a new way of preparing and stabilizing highly reactive C6-aldehydes on cellulose, and their exploitation in the development of new nanocellulose-based materials.

  12. [Amino acid and peptide derivatives of the tylosin family of macrolide antibiotics modified at the aldehyde group].

    PubMed

    Sumbatian, N V; Kuznetsova, I V; Karpenko, V V; Fedorova, N V; Chertkov, V A; Korshunova, G A; Bogdanov, A A

    2010-01-01

    Fourteen new functionally active amino acid and peptide derivatives of the antibiotics tylosin, desmycosin, and 5-O-mycaminosyltylonolide were synthesized in order to study the interaction of the growing polypeptide chain with the ribosomal tunnel. The conjugation of various amino acids and peptides with a macrolide aldehyde group was carried out by two methods: direct reductive amination with the isolation of the intermediate Schiff bases or through binding via oxime using the preliminarily obtained derivatives of 2-aminooxyacetic acid.

  13. Fluorescein aldehyde with disulfide functionality as a fluorescence turn-on probe for cysteine and homocysteine in HEPES buffer.

    PubMed

    Lee, Heejin; Kim, Hae-Jo

    2013-08-14

    We developed a fluorescein aldehyde probe with disulfide functionality for the fluorescence detection of biologically important thiols. The probe displayed highly selective responses to cysteine (Cys) and homocysteine (Hcy) over glutathione (GSH) due to the rapid ring formation reaction of Cys and Hcy with the aldehyde group of the probe and the concomitant cleavage of the disulfide group followed by subsequent intramolecular cyclization. The fluorescent probe also exhibited a highly sensitive fluorescence turn-on response to Hcy with a detection limit of 2.4 μM Hcy in HEPES buffer.

  14. A novel protein modification generating an aldehyde group in sulfatases: its role in catalysis and disease.

    PubMed

    von Figura, K; Schmidt, B; Selmer, T; Dierks, T

    1998-06-01

    In multiple sulfatase deficiency, a rare human lysosomal storage disorder, all known sulfatases are synthesized as catalytically poorly active polypeptides. Analysis of the latter has shown that they lack a protein modification that was detected in all members of the sulfatase family. This novel protein modification generates a 2-amino-3-oxopropanoic acid (C alpha-formylglycine) residue by oxidation of the thiol group of a cysteine that is conserved among all eukaryotic sulfatases. The oxidation occurs in the endoplasmic reticulum at a stage when the nascent polypeptide is not yet folded. The aldehyde is part of the catalytic site and is likely to act as an aldehyde hydrate. One of the geminal hydroxyl groups accepts the sulfate during sulfate ester cleavage leading to the formation of a covalently sulfated enzyme intermediate. The other hydroxyl is required for the subsequent elimination of the sulfate and regeneration of the aldehyde group. In some prokaryotic members of the sulfatase gene family, the DNA sequence predicts a serine residue, and not a cysteine. Analysis of one of these prokaryotic sulfatases, however, revealed the presence of the C alpha-formylglycine indicating that the aldehyde group is essential for all members of the sulfatase family and that it can be generated from either cysteine or serine.

  15. Genome-Wide Identification and Functional Classification of Tomato (Solanum lycopersicum) Aldehyde Dehydrogenase (ALDH) Gene Superfamily

    PubMed Central

    Lopez-Valverde, Francisco J.; Robles-Bolivar, Paula; Lima-Cabello, Elena; Gachomo, Emma W.; Kotchoni, Simeon O.

    2016-01-01

    Aldehyde dehydrogenases (ALDHs) is a protein superfamily that catalyzes the oxidation of aldehyde molecules into their corresponding non-toxic carboxylic acids, and responding to different environmental stresses, offering promising genetic approaches for improving plant adaptation. The aim of the current study is the functional analysis for systematic identification of S. lycopersicum ALDH gene superfamily. We performed genome-based ALDH genes identification and functional classification, phylogenetic relationship, structure and catalytic domains analysis, and microarray based gene expression. Twenty nine unique tomato ALDH sequences encoding 11 ALDH families were identified, including a unique member of the family 19 ALDH. Phylogenetic analysis revealed 13 groups, with a conserved relationship among ALDH families. Functional structure analysis of ALDH2 showed a catalytic mechanism involving Cys-Glu couple. However, the analysis of ALDH3 showed no functional gene duplication or potential neo-functionalities. Gene expression analysis reveals that particular ALDH genes might respond to wounding stress increasing the expression as ALDH2B7. Overall, this study reveals the complexity of S. lycopersicum ALDH gene superfamily and offers new insights into the structure-functional features and evolution of ALDH gene families in vascular plants. The functional characterization of ALDHs is valuable and promoting molecular breeding in tomato for the improvement of stress tolerance and signaling. PMID:27755582

  16. DNA-Templated Polymerization of Side-Chain-Functionalized Peptide Nucleic Acid Aldehydes

    PubMed Central

    Kleiner, Ralph E.; Brudno, Yevgeny; Birnbaum, Michael E.; Liu, David R.

    2009-01-01

    The DNA-templated polymerization of synthetic building blocks provides a potential route to the laboratory evolution of sequence-defined polymers with structures and properties not necessarily limited to those of natural biopolymers. We previously reported the efficient and sequence-specific DNA-templated polymerization of peptide nucleic acid (PNA) aldehydes. Here, we report the enzyme-free, DNA-templated polymerization of side-chain-functionalized PNA tetramer and pentamer aldehydes. We observed that the polymerization of tetramer and pentamer PNA building blocks with a single lysine-based side chain at various positions in the building block could proceed efficiently and sequence-specifically. In addition, DNA-templated polymerization also proceeded efficiently and in a sequence-specific manner with pentamer PNA aldehydes containing two or three lysine side chains in a single building block to generate more densely functionalized polymers. To further our understanding of side-chain compatibility and expand the capabilities of this system, we also examined the polymerization efficiencies of 20 pentamer building blocks each containing one of five different side-chain groups and four different side-chain regio- and stereochemistries. Polymerization reactions were efficient for all five different side-chain groups and for three of the four combinations of side-chain regio- and stereochemistries. Differences in the efficiency and initial rate of polymerization correlate with the apparent melting temperature of each building block, which is dependent on side-chain regio- and stereochemistry, but relatively insensitive to side-chain structure among the substrates tested. Our findings represent a significant step towards the evolution of sequence-defined synthetic polymers and also demonstrate that enzyme-free nucleic acid-templated polymerization can occur efficiently using substrates with a wide range of side-chain structures, functionalization positions within each

  17. Fatty aldehyde and fatty alcohol metabolism: review and importance for epidermal structure and function.

    PubMed

    Rizzo, William B

    2014-03-01

    Normal fatty aldehyde and alcohol metabolism is essential for epidermal differentiation and function. Long-chain aldehydes are produced by catabolism of several lipids including fatty alcohols, sphingolipids, ether glycerolipids, isoprenoid alcohols and certain aliphatic lipids that undergo α- or ω-oxidation. The fatty aldehyde generated by these pathways is chiefly metabolized to fatty acid by fatty aldehyde dehydrogenase (FALDH, alternately known as ALDH3A2), which also functions to oxidize fatty alcohols as a component of the fatty alcohol:NAD oxidoreductase (FAO) enzyme complex. Genetic deficiency of FALDH/FAO in patients with Sjögren-Larsson syndrome (SLS) results in accumulation of fatty aldehydes, fatty alcohols and related lipids (ether glycerolipids, wax esters) in cultured keratinocytes. These biochemical changes are associated with abnormalities in formation of lamellar bodies in the stratum granulosum and impaired delivery of their precursor membranes to the stratum corneum (SC). The defective extracellular SC membranes are responsible for a leaky epidermal water barrier and ichthyosis. Although lamellar bodies appear to be the pathogenic target for abnormal fatty aldehyde/alcohol metabolism in SLS, the precise biochemical mechanisms are yet to be elucidated. Nevertheless, studies in SLS highlight the critical importance of FALDH and normal fatty aldehyde/alcohol metabolism for epidermal function. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.

  18. Fatty Aldehyde and Fatty Alcohol Metabolism: Review and Importance for Epidermal Structure and Function

    PubMed Central

    Rizzo, William B.

    2014-01-01

    Normal fatty aldehyde and alcohol metabolism is essential for epidermal differentiation and function. Long-chain aldehydes are produced by catabolism of several lipids including fatty alcohols, sphingolipids, ether glycerolipids, isoprenoid alcohols and certain aliphatic lipids that undergo α- or ω-oxidation. The fatty aldehyde generated by these pathways is chiefly metabolized to fatty acid by fatty aldehyde dehydrogenase (FALDH, alternately known as ALDH3A2), which also functions to oxidize fatty alcohols as a component of the fatty alcohol:NAD oxidoreductase (FAO) enzyme complex. Genetic deficiency of FALDH/FAO in patients with Sjögren-Larsson syndrome (SLS) results in accumulation of fatty aldehydes, fatty alcohols and related lipids (ether glycerolipids, wax esters) in cultured keratinocytes. These biochemical changes are associated with abnormalities in formation of lamellar bodies in the stratum granulosum and impaired delivery of their precursor membranes to the stratum corneum (SC). The defective extracellular SC membranes are responsible for a leaky epidermal water barrier and ichthyosis. Although lamellar bodies appear to be the pathogenic target for abnormal fatty aldehyde/alcohol metabolism in SLS, the precise biochemical mechanisms are yet to be elucidated. Nevertheless, studies in SLS highlight the critical importance of FALDH and normal fatty aldehyde/alcohol metabolism for epidermal function. PMID:24036493

  19. Aldehyde dehydrogenase 2 activation in heart failure restores mitochondrial function and improves ventricular function and remodelling

    PubMed Central

    Gomes, Katia M.S.; Campos, Juliane C.; Bechara, Luiz R.G.; Queliconi, Bruno; Lima, Vanessa M.; Disatnik, Marie-Helene; Magno, Paulo; Chen, Che-Hong; Brum, Patricia C.; Kowaltowski, Alicia J.; Mochly-Rosen, Daria; Ferreira, Julio C.B.

    2014-01-01

    Aims We previously demonstrated that pharmacological activation of mitochondrial aldehyde dehydrogenase 2 (ALDH2) protects the heart against acute ischaemia/reperfusion injury. Here, we determined the benefits of chronic activation of ALDH2 on the progression of heart failure (HF) using a post-myocardial infarction model. Methods and results We showed that a 6-week treatment of myocardial infarction-induced HF rats with a selective ALDH2 activator (Alda-1), starting 4 weeks after myocardial infarction at a time when ventricular remodelling and cardiac dysfunction were present, improved cardiomyocyte shortening, cardiac function, left ventricular compliance and diastolic function under basal conditions, and after isoproterenol stimulation. Importantly, sustained Alda-1 treatment showed no toxicity and promoted a cardiac anti-remodelling effect by suppressing myocardial hypertrophy and fibrosis. Moreover, accumulation of 4-hydroxynonenal (4-HNE)-protein adducts and protein carbonyls seen in HF was not observed in Alda-1-treated rats, suggesting that increasing the activity of ALDH2 contributes to the reduction of aldehydic load in failing hearts. ALDH2 activation was associated with improved mitochondrial function, including elevated mitochondrial respiratory control ratios and reduced H2O2 release. Importantly, selective ALDH2 activation decreased mitochondrial Ca2+-induced permeability transition and cytochrome c release in failing hearts. Further supporting a mitochondrial mechanism for ALDH2, Alda-1 treatment preserved mitochondrial function upon in vitro aldehydic load. Conclusions Selective activation of mitochondrial ALDH2 is sufficient to improve the HF outcome by reducing the toxic effects of aldehydic overload on mitochondrial bioenergetics and reactive oxygen species generation, suggesting that ALDH2 activators, such as Alda-1, have a potential therapeutic value for treating HF patients. PMID:24817685

  20. Oligonucleotide Immobilization and Hybridization on Aldehyde-Functionalized Poly(2-hydroxyethyl methacrylate) Brushes.

    PubMed

    Bilgic, Tugba; Klok, Harm-Anton

    2015-11-09

    DNA biosensing requires high oligonucleotide binding capacity interface chemistries that can be tuned to maximize probe presentation as well as hybridization efficiency. This contribution investigates the feasibility of aldehyde-functionalized poly(2-hydroxyethyl methacrylate) (PHEMA) brush-based interfaces for oligonucleotide binding and hybridization. These polymer brushes, which allow covalent immobilization of oligonucleotides, are prepared by surface-initiated atom transfer radical polymerization (SI-ATRP) of HEMA followed by a postpolymerization oxidation step to generate side chain aldehyde groups. A series of polymer brushes covering a range of film thicknesses and grafting densities was investigated with regard to their oligonucleotide binding capacity as well as their ability to support oligonucleotide hybridization. Densely grafted brushes were found to have probe oligonucleotide binding capacities of up to ∼30 pmol/cm(2). Increasing the thickness of these densely grafted brush films, however, resulted in a decrease in the oligonucleotide binding capacity. Less densely grafted brushes possess binding capacities of ∼10 pmol/cm(2), which did not significantly depend on film thickness. The oligonucleotide hybridization efficiencies, however, were highest (93%) on those brushes that present the lowest surface concentration of the probe oligonucleotide. These results highlight the importance of optimizing the probe oligonucleotide surface concentration and binding interface chemistry. The versatility and tunability of the PHEMA-based brushes presented herein makes these films a very attractive platform for the immobilization and hybridization of oligonucleotides.

  1. Functionalization vs. fragmentation: n-aldehyde oxidation mechanisms and secondary organic aerosol formation.

    PubMed

    Chacon-Madrid, Heber J; Presto, Albert A; Donahue, Neil M

    2010-11-14

    Because of their relatively well-understood chemistry and atmospheric relevance, aldehydes represent a good model system for carbon-carbon fragmentation reactions in organic-aerosol aging mechanisms. Small aldehydes such as ethanal and propanal react with OH radicals under high NO(x) conditions to form formaldehyde and ethanal, respectively, with nearly unit yield. CO(2) is formed as a coproduct. This path implies the formation of the C(n-1) aldehyde, or an aldehyde with one fewer methylene group than the parent. However, as the carbon number of the n-aldehyde increases, reaction with the carbon backbone becomes more likely and the C(n-1) formation path becomes less important. In this work we oxidized n-pentanal, n-octanal, n-undecanal and n-tridecanal with OH radicals at high NO(x). The C(n-1) aldehyde molar yields after the peroxyl radical + NO reaction were 69 ± 15, 36 ± 10, 16 ± 5 and 4 ± 1%, respectively. Complementary structure-activity relationship calculations of important rate constants enable estimates of branching ratios between several intermediates of the C(n)n-aldehyde reaction with OH: C(n) peroxyacyl nitrate versus C(n) alkoxyacyl radical formation, C(n-1) alkyl nitrate versus C(n-1) alkoxy radical, and C(n-1) aldehyde formation versus isomerization products. We also measured SOA mass yields, which we compare with analogous n-alkanes to understand the effect of fragmentation on organic-aerosol formation.

  2. Synthesis of chiral alpha-amino aldehydes linked by their amine function to solid support.

    PubMed

    Cantel, Sonia; Heitz, Annie; Martinez, Jean; Fehrentz, Jean-Alain

    2004-09-01

    The anchoring of an alpha-amino-acid derivative by its amine function on to a solid support allows some chemical reactions starting from the carboxylic acid function. This paper describes the preparation of alpha-amino aldehydes linked to the support by their amine function. This was performed by reduction with LiAlH4 of the corresponding Weinreb amide linked to the resin. The aldehydes obtained were then involved in Wittig or reductive amination reactions. In addition, the linked Weinreb amide was reacted with methylmagnesium bromide to yield the corresponding ketone. After cleavage from the support, the compounds were obtained in good to excellent yields and characterized.

  3. Asymmetric Functional Organozinc Additions to Aldehydes Catalyzed by 1,1′-Bi-2-naphthols (BINOLs)†

    PubMed Central

    2015-01-01

    Conspectus Chiral alcohols are ubiquitous in organic structures. One efficient method to generate chiral alcohols is the catalytic asymmetric addition of a carbon nucleophile to a carbonyl compound since this process produces a C–C bond and a chiral center simultaneously. In comparison with the carbon nucleophiles such as an organolithium or a Grignard reagent, an organozinc reagent possesses the advantages of functional group tolerance and more mild reaction conditions. Catalytic asymmetric reactions of aldehydes with arylzincs, vinylzincs, and alkynylzincs to generate functional chiral alcohols are discussed in this Account. Our laboratory has developed a series of 1,1′-bi-2-naphthol (BINOL)-based chiral catalysts for the asymmetric organozinc addition to aldehydes. It is found that the 3,3′-dianisyl-substituted BINOLs are not only highly enantioselective for the alkylzinc addition to aldehydes, but also highly enantioselective for the diphenylzinc addition to aldehydes. A one-step synthesis has been achieved to incorporate Lewis basic amine groups into the 3,3′-positions of the partially hydrogenated H8BINOL. These H8BINOL–amine compounds have become more generally enantioselective and efficient catalysts for the diphenylzinc addition to aldehydes to produce various types of chiral benzylic alcohols. The application of the H8BINOL–amine catalysts is expanded by using in situ generated diarylzinc reagents from the reaction of aryl iodides with ZnEt2, which still gives high enantioselectivity and good catalytic activity. Such a H8BINOL–amine compound is further found to catalyze the highly enantioselective addition of vinylzincs, in situ generated from the treatment of vinyl iodides with ZnEt2, to aldehydes to give the synthetically very useful chiral allylic alcohols. We have discovered that the unfunctionalized BINOL in combination with ZnEt2 and Ti(OiPr)4 can catalyze the terminal alkyne addition to aldehydes to produce chiral propargylic alcohols

  4. Aldehyde Dehydrogenases in Arabidopsis thaliana: Biochemical Requirements, Metabolic Pathways, and Functional Analysis.

    PubMed

    Stiti, Naim; Missihoun, Tagnon D; Kotchoni, Simeon O; Kirch, Hans-Hubert; Bartels, Dorothea

    2011-01-01

    Aldehyde dehydrogenases (ALDHs) are a family of enzymes which catalyze the oxidation of reactive aldehydes to their corresponding carboxylic acids. Here we summarize molecular genetic and biochemical analyses of selected ArabidopsisALDH genes. Aldehyde molecules are very reactive and are involved in many metabolic processes but when they accumulate in excess they become toxic. Thus activity of aldehyde dehydrogenases is important in regulating the homeostasis of aldehydes. Overexpression of some ALDH genes demonstrated an improved abiotic stress tolerance. Despite the fact that several reports are available describing a role for specific ALDHs, their precise physiological roles are often still unclear. Therefore a number of genetic and biochemical tools have been generated to address the function with an emphasis on stress-related ALDHs. ALDHs exert their functions in different cellular compartments and often in a developmental and tissue specific manner. To investigate substrate specificity, catalytic efficiencies have been determined using a range of substrates varying in carbon chain length and degree of carbon oxidation. Mutational approaches identified amino acid residues critical for coenzyme usage and enzyme activities.

  5. Target-Specific Capture of Environmentally Relevant Gaseous Aldehydes and Carboxylic Acids with Functional Nanoparticles.

    PubMed

    Campbell, McKenzie L; Guerra, Fernanda D; Dhulekar, Jhilmil; Alexis, Frank; Whitehead, Daniel C

    2015-10-12

    Aldehyde and carboxylic acid volatile organic compounds (VOCs) present significant environmental concern due to their prevalence in the atmosphere. We developed biodegradable functional nanoparticles comprised of poly(d,l-lactic acid)-poly(ethylene glycol)-poly(ethyleneimine) (PDLLA-PEG-PEI) block co-polymers that capture these VOCs by chemical reaction. Polymeric nanoparticles (NPs) preparation involved nanoprecipitation and surface functionalization with branched PEI. The PDLLA-PEG-PEI NPs were characterized by using TGA, IR, (1) H NMR, elemental analysis, and TEM. The materials feature 1°, 2°, and 3° amines on their surface, capable of capturing aldehydes and carboxylic acids from gaseous mixtures. Aldehydes were captured by a condensation reaction forming imines, whereas carboxylic acids were captured by acid/base reaction. These materials reacted selectively with target contaminants obviating off-target binding when challenged by other VOCs with orthogonal reactivity. The NPs outperformed conventional activated carbon sorbents.

  6. Aldehyde dehydrogenase 2 is associated with cognitive functions in patients with Parkinson’s disease

    PubMed Central

    Yu, Rwei-Ling; Tan, Chun-Hsiang; Lu, Ying-Che; Wu, Ruey-Meei

    2016-01-01

    Neurotransmitter degradation has been proposed to cause the accumulation of neurotoxic metabolites. The metabolism of these metabolites involves aldehyde dehydrogenase 2 (ALDH2). The Asian-specific single nucleotide polymorphism rs671 causes reduced enzyme activity. This study aims to explore whether Parkinson’s disease (PD) patients with reduced ALDH2 activity owing to the rs671 polymorphism are at risk for neuropsychological impairments. A total of 139 PD patients were recruited. Each participant was assessed for medical characteristics and their ALDH2 genotype. The Mini-Mental State Examination (MMSE), the Clinical Dementia Rating Scale and the Frontal Behavioral Inventory were used to measure neuropsychological functions. We found that the MMSE scores were significantly lower in patients with inactive ALDH2 (U = 1873.5, p = 0.02). The presence of cognitive impairments was significantly more frequent in the inactive ALDH2 group (46.0%) than in the active ALDH2 group (26.3%) (χ2 = 5.886, p = 0.01). The inactive group showed significant deterioration in hobbies and exhibited more severe “disorganization” and “hyper-sexuality” behaviours. The additive effects of the allele on the development of cognitive impairments in PD patients may be an important finding that provides further insight into the pathogenic mechanism of cognitive dysfunction in PD. PMID:27453488

  7. Spectroscopic and molecular structure investigation of the phosphorus-containing G‧2 dendrimer with terminal aldehyde groups using DFT method

    NASA Astrophysics Data System (ADS)

    Furer, V. L.; Vandyukov, A. E.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2015-02-01

    The FTIR and FT Raman spectra of the second generation dendrimer G‧2 built from thiophosphoryl core with terminal aldehyde groups have been recorded. The structural optimization and normal mode analysis were performed for model compound C, consisting of thiophosphoryl core, one branch with three repeated units, and four 4-oxybenzaldehyde terminal groups on the basis of the density functional theory (DFT) at the PBE/TZ2P level. The vibrational frequencies, infrared and Raman intensities for the t,g,g- and t,-g,g-conformers of the terminal groups were calculated. The t,g,g-conformer is 2.0 kcal/mol less stable compared to t,-g,g-conformer. A reliable assignment of the fundamental bands observed in the experimental IR and Raman spectra of dendrimer was achieved. For the low generations (G‧1 to G‧3) the disk form of studied dendrimer molecules is the most probable. For higher generations, the shape of dendrimer molecules will be that of a cauliflower.

  8. A Reusable Co Catalyst for the Selective Hydrogenation of Functionalized Nitroarenes and the Direct Synthesis of Imines and Benzimidazoles from Nitroarenes and Aldehydes.

    PubMed

    Schwob, Tobias; Kempe, Rhett

    2016-11-21

    The use of abundantly available transition metals in reactions that have been preferentially mediated by rare noble metals, for example, hydrogenations, is a desirable aim in catalysis and an attractive strategy for element conservation. The observation of novel selectivity patterns with such inexpensive metal catalysts is especially appealing. Herein, we report a novel, robust, and reusable cobalt catalyst that permits the selective hydrogenation of nitroarenes in the presence of highly hydrogenation-sensitive functional groups, as well as the direct synthesis of imines from nitroarenes and aldehydes or ketones in the presence of such substituents. Furthermore, we introduce the first base-metal-mediated direct synthesis of benzimidazoles from nitroarenes and aldehydes. Functional groups that are easy to hydrogenate are again well tolerated.

  9. NADP-Dependent Aldehyde Dehydrogenase from Archaeon Pyrobaculum sp.1860: Structural and Functional Features

    PubMed Central

    Petrova, Tatiana E.; Artemova, Natalia V.; Boyko, Konstantin M.; Shabalin, Ivan G.; Rakitina, Tatiana V.; Polyakov, Konstantin M.; Popov, Vladimir O.

    2016-01-01

    We present the functional and structural characterization of the first archaeal thermostable NADP-dependent aldehyde dehydrogenase AlDHPyr1147. In vitro, AlDHPyr1147 catalyzes the irreversible oxidation of short aliphatic aldehydes at 60–85°С, and the affinity of AlDHPyr1147 to the NADP+ at 60°С is comparable to that for mesophilic analogues at 25°С. We determined the structures of the apo form of AlDHPyr1147 (3.04 Å resolution), three binary complexes with the coenzyme (1.90, 2.06, and 2.19 Å), and the ternary complex with the coenzyme and isobutyraldehyde as a substrate (2.66 Å). The nicotinamide moiety of the coenzyme is disordered in two binary complexes, while it is ordered in the ternary complex, as well as in the binary complex obtained after additional soaking with the substrate. AlDHPyr1147 structures demonstrate the strengthening of the dimeric contact (as compared with the analogues) and the concerted conformational flexibility of catalytic Cys287 and Glu253, as well as Leu254 and the nicotinamide moiety of the coenzyme. A comparison of the active sites of AlDHPyr1147 and dehydrogenases characterized earlier suggests that proton relay systems, which were previously proposed for dehydrogenases of this family, are blocked in AlDHPyr1147, and the proton release in the latter can occur through the substrate channel. PMID:27956891

  10. Molecular structural, non-linear optical, second order perturbation and Fukui studies of Indole-3-Aldehyde using density functional calculations.

    PubMed

    Muthu, S; Maheswari, J Uma; Sundius, Tom

    2013-04-01

    Indole-3-Aldehyde is a new organic non-linear material having good second harmonic generation. The optimized molecular geometry, harmonic vibrational frequencies, infrared intensities of Indole-3-Aldehyde (I3A, C9H7NO) in the ground state were carried out by using density functional theory (B3LYP) method with 6-31G(d,p) basis set. A detailed interpretation of the infrared spectrum of Indole-3-Aldehyde is reported. The vibrational frequencies are calculated and compared with experimental FT-IR spectra. The theoretical spectrograms of FT-IR of the title compound have been constructed in addition, theoretical information like ONIOM, potential energy surface, NBO, and Fukui function are also calculated. Unambiguous vibrational assignment of all the fundamentals was made using the potential energy distribution.

  11. Alcohol and aldehyde dehydrogenases: structures of the human liver enzymes, functional properties and evolutionary aspects.

    PubMed

    Jörnvall, H; Hempel, J; von Bahr-Lindström, H; Höög, J O; Vallee, B L

    1987-01-01

    polyol dehydrogenases are encountered. The two isozymes of human aldehyde dehydrogenase also exhibit considerable differences, with only 68% structural identity. The results show an early divergence into isozymes before the man/horse species radiation. Cys-302 is a functionally important residue and is located in one of the regions with conserved hydrophobic properties. Other regions with large differences in hydropathic properties may explain the absence of cross-hybridizing isozyme forms of human liver aldehyde dehydrogenase.

  12. Enhanced response speed and selectivity of fluorescein-based H2S probe via the cleavage of nitrobenzene sulfonyl ester assisted by ortho aldehyde groups.

    PubMed

    Lv, Jing; Wang, Fang; Qiang, Jian; Ren, Xintong; Chen, Yahui; Zhang, Zhijie; Wang, Yong; Zhang, Wei; Chen, Xiaoqiang

    2017-01-15

    In this work, we developed three fluorescent probes (F-1, F-2, and F-3) based on fluorescein, mono-formylated fluorescein, and bis-formylated fluorescein for hydrogen sulfide (H2S) detection. The probe F-3, which bears two aldehyde groups, exhibited the fastest response. This fast response is attributed to the ortho effect of the aldehyde group, which enables fast nucleophilic addition of H2S to an aldehyde group and subsequent intramolecular thiolysis of dinitrophenyl ether. In addition, the aldehyde groups on F-3 react with biothiols (e.g., cysteine, homocysteine) to form thiazolidine diastereomers, which suppress the fluorescence of fluorescein. The introduction of two aldehyde groups also resulted in high selectivity of F-3 towards H2S. Furthermore, good linearity was observed between F-3 fluorescence intensity at 510nm and H2S concentration in the range of 0-10µM. F-3 exhibited a detection limit as low as 0.024μM. Confocal laser scanning micrographs of HeLa cells incubated with F-3 confirmed that F-3 is cell-permeable and can successfully detect H2S in living cells.

  13. A new resistance source of aldehyde reductase functions from Scheffersomyces stipitis against biomass fermentation inhibitor furfural

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aldehyde inhibitory compounds derived from lignocellulosic biomass pretreatment are a major class of toxic chemicals that interfere with microbial growth and subsequent fermentation for advanced biofuels production. This study identified five uncharacterized putative genes of Scheffersomyces stipiti...

  14. Coniferyl Aldehyde Attenuates Radiation Enteropathy by Inhibiting Cell Death and Promoting Endothelial Cell Function

    PubMed Central

    Son, Yeonghoon; Jang, Jun-Ho; Lee, Yoon-Jin; Kim, Sung-Ho; Ko, Young-Gyo; Lee, Yun-Sil; Lee, Hae-June

    2015-01-01

    Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA), an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR) to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury. CA clearly alleviated acute radiation-induced intestinal damage, as reflected by the histopathological data and it also attenuated sub-acute enteritis. CA prevented intestinal crypt cell death and protected the microvasculature in the lamina propria during the acute and sub-acute phases of damage. CA induced HSF1 and HSP70 expression in both intestinal epithelial cells and endothelial cells in vitro. Additionally, CA protected against not only the apoptotic cell death of both endothelial and epithelial cells but also the loss of endothelial cell function following IR, indicating that CA has beneficial effects on the intestine. Our results provide novel insight into the effects of CA and suggest its role as a therapeutic candidate for radiation-induced enteropathy due to its ability to promote rapid re-proliferation of the intestinal epithelium by the synergic effects of the inhibition of cell death and the promotion of endothelial cell function. PMID:26029925

  15. Coniferyl aldehyde attenuates radiation enteropathy by inhibiting cell death and promoting endothelial cell function.

    PubMed

    Jeong, Ye-Ji; Jung, Myung Gu; Son, Yeonghoon; Jang, Jun-Ho; Lee, Yoon-Jin; Kim, Sung-Ho; Ko, Young-Gyo; Lee, Yun-Sil; Lee, Hae-June

    2015-01-01

    Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA), an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR) to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury. CA clearly alleviated acute radiation-induced intestinal damage, as reflected by the histopathological data and it also attenuated sub-acute enteritis. CA prevented intestinal crypt cell death and protected the microvasculature in the lamina propria during the acute and sub-acute phases of damage. CA induced HSF1 and HSP70 expression in both intestinal epithelial cells and endothelial cells in vitro. Additionally, CA protected against not only the apoptotic cell death of both endothelial and epithelial cells but also the loss of endothelial cell function following IR, indicating that CA has beneficial effects on the intestine. Our results provide novel insight into the effects of CA and suggest its role as a therapeutic candidate for radiation-induced enteropathy due to its ability to promote rapid re-proliferation of the intestinal epithelium by the synergic effects of the inhibition of cell death and the promotion of endothelial cell function.

  16. Aldose and aldehyde reductases : structure-function studies on the coenzyme and inhibitor-binding sites.

    SciTech Connect

    El-Kabbani, O.; Old, S. E.; Ginell, S. L.; Carper, D. A.; Biosciences Division; Monash Univ.; NIH

    1999-09-03

    PURPOSE: To identify the structural features responsible for the differences in coenzyme and inhibitor specificities of aldose and aldehyde reductases. METHODS: The crystal structure of porcine aldehyde reductase in complex with NADPH and the aldose reductase inhibitor sorbinil was determined. The contribution of each amino acid lining the coenzyme-binding site to the binding of NADPH was calculated using the Discover package. In human aldose reductase, the role of the non-conserved Pro 216 (Ser in aldehyde reductase) in the binding of coenzyme was examined by site-directed mutagenesis. RESULTS: Sorbinil binds to the active site of aldehyde reductase and is hydrogen-bonded to Trp 22, Tyr 50, His 113, and the non-conserved Arg 312. Unlike tolrestat, the binding of sorbinil does not induce a change in the side chain conformation of Arg 312. Mutation of Pro 216 to Ser in aldose reductase makes the binding of coenzyme more similar to that of aldehyde reductase. CONCLUSIONS: The participation of non-conserved active site residues in the binding of inhibitors and the differences in the structural changes required for the binding to occur are responsible for the differences in the potency of inhibition of aldose and aldehyde reductases. We report that the non-conserved Pro 216 in aldose reductase contributes to the tight binding of NADPH.

  17. Comparative Study on Single-Molecule Junctions of Alkane- and Benzene-Based Molecules with Carboxylic Acid/Aldehyde as the Anchoring Groups

    NASA Astrophysics Data System (ADS)

    Chen, Fang; Peng, Lin-Lu; Hong, Ze-Wen; Mao, Jin-Chuan; Zheng, Ju-Fang; Shao, Yong; Niu, Zhen-Jiang; Zhou, Xiao-Shun

    2016-08-01

    We have measured the alkane and benzene-based molecules with aldehyde and carboxylic acid as anchoring groups by using the electrochemical jump-to-contact scanning tunneling microscopy break junction (ECSTM-BJ) approach. The results show that molecule with benzene backbone has better peak shape and intensity than those with alkane backbone. Typically, high junction formation probability for same anchoring group (aldehyde and carboxylic acid) with benzene backbone is found, which contributes to the stronger attractive interaction between Cu and molecules with benzene backbone. The present work shows the import role of backbone in junction, which can guide the design molecule to form effective junction for studying molecular electronics.

  18. Expanded Hematopoietic Progenitor Cells Reselected for High Aldehyde Dehydrogenase Activity Demonstrate Islet Regenerative Functions.

    PubMed

    Seneviratne, Ayesh K; Bell, Gillian I; Sherman, Stephen E; Cooper, Tyler T; Putman, David M; Hess, David A

    2016-04-01

    Human umbilical cord blood (UCB) hematopoietic progenitor cells (HPC) purified for high aldehyde dehydrogenase activity (ALDH(hi) ) stimulate islet regeneration after transplantation into mice with streptozotocin-induced β cell deletion. However, ALDH(hi) cells represent a rare progenitor subset and widespread use of UCB ALDH(hi) cells to stimulate islet regeneration will require progenitor cell expansion without loss of islet regenerative functions. Here we demonstrate that prospectively purified UCB ALDH(hi) cells expand efficiently under serum-free, xeno-free conditions with minimal growth factor supplementation. Consistent with the concept that ALDH-activity is decreased as progenitor cells differentiate, kinetic analyses over 9 days revealed the frequency of ALDH(hi) cells diminished as culture time progressed such that total ALDH(hi) cell number was maximal (increased 3-fold) at day 6. Subsequently, day 6 expanded cells (bulk cells) were sorted after culture to reselect differentiated progeny with low ALDH-activity (ALDH(lo) subset) from less differentiated progeny with high ALDH-activity (ALDH(hi) subset). The ALDH(hi) subset retained primitive cell surface marker coexpression (32.0% ± 7.0% CD34(+) /CD38(-) cells, 37.0% ± 6.9% CD34(+) /CD133(+) cells), and demonstrated increased hematopoietic colony forming cell function compared with the ALDH(lo) subset. Notably, bulk cells or ALDH(lo) cells did not possess the functional capacity to lower hyperglycemia after transplantation into streptozotocin-treated NOD/SCID mice. However, transplantation of the repurified ALDH(hi) subset significantly reduced hyperglycemia, improved glucose tolerance, and increased islet-associated cell proliferation and capillary formation. Thus, expansion and delivery of reselected UCB cells that retain high ALDH-activity after short-term culture represents an improved strategy for the development of cellular therapies to enhance islet regeneration in situ.

  19. Cluster functional renormalization group

    NASA Astrophysics Data System (ADS)

    Reuther, Johannes; Thomale, Ronny

    2014-01-01

    Functional renormalization group (FRG) has become a diverse and powerful tool to derive effective low-energy scattering vertices of interacting many-body systems. Starting from a free expansion point of the action, the flow of the RG parameter Λ allows us to trace the evolution of the effective one- and two-particle vertices towards low energies by taking into account the vertex corrections between all parquet channels in an unbiased fashion. In this work, we generalize the expansion point at which the diagrammatic resummation procedure is initiated from a free UV limit to a cluster product state. We formulate a cluster FRG scheme where the noninteracting building blocks (i.e., decoupled spin clusters) are treated exactly, and the intercluster couplings are addressed via RG. As a benchmark study, we apply our cluster FRG scheme to the spin-1/2 bilayer Heisenberg model (BHM) on a square lattice where the neighboring sites in the two layers form the individual two-site clusters. Comparing with existing numerical evidence for the BHM, we obtain reasonable findings for the spin susceptibility, the spin-triplet excitation energy, and quasiparticle weight even in coupling regimes close to antiferromagnetic order. The concept of cluster FRG promises applications to a large class of interacting electron systems.

  20. Structural and functional analysis of betaine aldehyde dehydrogenase from Staphylococcus aureus

    PubMed Central

    Halavaty, Andrei S.; Rich, Rebecca L.; Chen, Chao; Joo, Jeong Chan; Minasov, George; Dubrovska, Ievgeniia; Winsor, James R.; Myszka, David G.; Duban, Mark; Shuvalova, Ludmilla; Yakunin, Alexander F.; Anderson, Wayne F.

    2015-01-01

    When exposed to high osmolarity, methicillin-resistant Staphylococcus aureus (MRSA) restores its growth and establishes a new steady state by accumulating the osmoprotectant metabolite betaine. Effective osmoregulation has also been implicated in the acquirement of a profound antibiotic resistance by MRSA. Betaine can be obtained from the bacterial habitat or produced intracellularly from choline via the toxic betaine aldehyde (BA) employing the choline dehydrogenase and betaine aldehyde dehydrogenase (BADH) enzymes. Here, it is shown that the putative betaine aldehyde dehydrogenase SACOL2628 from the early MRSA isolate COL (SaBADH) utilizes betaine aldehyde as the primary substrate and nicotinamide adenine dinucleotide (NAD+) as the cofactor. Surface plasmon resonance experiments revealed that the affinity of NAD+, NADH and BA for SaBADH is affected by temperature, pH and buffer composition. Five crystal structures of the wild type and three structures of the Gly234Ser mutant of SaBADH in the apo and holo forms provide details of the molecular mechanisms of activity and substrate specificity/inhibition of this enzyme. PMID:25945581

  1. Structural and functional analysis of betaine aldehyde dehydrogenase from Staphylococcus aureus.

    PubMed

    Halavaty, Andrei S; Rich, Rebecca L; Chen, Chao; Joo, Jeong Chan; Minasov, George; Dubrovska, Ievgeniia; Winsor, James R; Myszka, David G; Duban, Mark; Shuvalova, Ludmilla; Yakunin, Alexander F; Anderson, Wayne F

    2015-05-01

    When exposed to high osmolarity, methicillin-resistant Staphylococcus aureus (MRSA) restores its growth and establishes a new steady state by accumulating the osmoprotectant metabolite betaine. Effective osmoregulation has also been implicated in the acquirement of a profound antibiotic resistance by MRSA. Betaine can be obtained from the bacterial habitat or produced intracellularly from choline via the toxic betaine aldehyde (BA) employing the choline dehydrogenase and betaine aldehyde dehydrogenase (BADH) enzymes. Here, it is shown that the putative betaine aldehyde dehydrogenase SACOL2628 from the early MRSA isolate COL (SaBADH) utilizes betaine aldehyde as the primary substrate and nicotinamide adenine dinucleotide (NAD(+)) as the cofactor. Surface plasmon resonance experiments revealed that the affinity of NAD(+), NADH and BA for SaBADH is affected by temperature, pH and buffer composition. Five crystal structures of the wild type and three structures of the Gly234Ser mutant of SaBADH in the apo and holo forms provide details of the molecular mechanisms of activity and substrate specificity/inhibition of this enzyme.

  2. Space group revsion of the triclinic polymorph of salicyl-aldehyde azine.

    PubMed

    Saeed, Aamer; Bolte, Michael; Arshad, Muhammad

    2012-02-01

    The structure of the title compound, C(14)H(12)N(2)O(2) {systematic name: 2,2'-[hydrazinediylidenebis(methanylyl-idene)]diphen-ol}, has already been determined in the triclinic space group P[Formula: see text] with Z = 4 [El-Medani, Aboaly, Abdalla & Ramadan (2004 ▶). Spectrosc. Lett.37, 619-632]. However, the correct space group should be P2(1)/c with Z = 4. This structure is a new polymorph of the already known monoclinic polymorph of salicyladehyde azine, which crystallizes in space group P2(1)/n with Z = 2. The benzene rings form a dihedral angle of 46.12 (9)°. Two intramolucular O-H⋯N hydrogen bonds occur.

  3. Fluorescence of the Flavin group in choline oxidase. Insights and analytical applications for the determination of choline and betaine aldehyde.

    PubMed

    Ortega, E; de Marcos, S; Sanz-Vicente, I; Ubide, C; Ostra, M; Vidal, M; Galbán, J

    2016-01-15

    Choline oxidase (ChOx) is a flavoenzyme catalysing the oxidation of choline (Ch) to betaine aldehyde (BA) and glycine betaine (GB). In this paper a fundamental study of the intrinsic fluorescence properties of ChOx due to Flavin Adenine Dinucleotide (FAD) is presented and some analytical applications are studied in detail. Firstly, an unusual alteration in the excitation spectra, in comparison with the absorption spectra, has been observed as a function of the pH. This is ascribed to a change of polarity in the excited state. Secondly, the evolution of the fluorescence spectra during the reaction seems to indicate that the reaction takes place in two consecutive, but partially overlapped, steps and each of them follows a different mechanism. Thirdly, the chemical system can be used to determine the Ch concentration in the range from 5×10(-6)M to 5×10(-5)M (univariate and multivariate calibration) in the presence of BA as interference, and the joint Ch+BA concentration in the range 5×10(-6)-5×10(-4)M (multivariate calibration) with mean errors under 10%; a semiquantitative determination of the BA concentration can be deduced by difference. Finally, Ch has been successfully determined in an infant milk sample.

  4. Remote sulfonamido group enhances reactivity and selectivity for asymmetric Michael addition of nitroalkanes to α,β-unsaturated aldehydes.

    PubMed

    Huang, Yu-Chao; Uang, Biing-Jiun

    2014-09-01

    The pyrrolidine-camphorsulfonamide-based catalyst 1 a catalyzes the enantioselective conjugate addition of nitroalkanes to α,β-unsaturated aldehydes in the presence of five equivalents of water in iPrOH to give the corresponding chiral Michael adducts in good yields and high enantioselectivities (up to 99% ee) with a catalyst loading as low as 1 mol%.

  5. Deleterious effects of reactive aldehydes and glycated proteins on macrophage proteasomal function: possible links between diabetes and atherosclerosis.

    PubMed

    Moheimani, Fatemeh; Morgan, Philip E; van Reyk, David M; Davies, Michael J

    2010-06-01

    People with diabetes experience chronic hyperglycemia and are at a high risk of developing atherosclerosis and microvascular disease. Reactions of glucose, or aldehydes derived from glucose (e.g. methylglyoxal, glyoxal, or glycolaldehyde), with proteins result in glycation that ultimately yield advanced glycation end products (AGE). AGE are present at elevated levels in plasma and atherosclerotic lesions from people with diabetes, and previous in vitro studies have postulated that the presence of these materials is deleterious to cell function. This accumulation of AGE and glycated proteins within cells may arise from either increased formation and/or ineffective removal by cellular proteolytic systems, such as the proteasomes, the major multi-enzyme complex that removes proteins within cells. In this study it is shown that whilst high glucose concentrations fail to modify proteasome enzyme activities in J774A.1 macrophage-like cell extracts, reactive aldehydes enhanced proteasomal enzyme activities. In contrast BSA, pre-treated with high glucose for 8 weeks, inhibited both the chymotrypsin-like and caspase-like activities. BSA glycated using methylglyoxal or glycolaldehyde, also inhibited proteasomal activity though to differing extents. This suppression of proteasome activity by glycated proteins may result in further intracellular accumulation of glycated proteins with subsequent deleterious effects on cellular function.

  6. Ionic liquid-functionalized silica for selective solid-phase extraction of organic acids, amines and aldehydes.

    PubMed

    Vidal, Lorena; Parshintsev, Jevgeni; Hartonen, Kari; Canals, Antonio; Riekkola, Marja-Liisa

    2012-02-24

    Three ionic liquid (IL)-functionalized silica materials, imidazolium, N-methylimidazolium and 1-alkyl-3-(propyl-3-sulfonate) imidazolium, were synthesised and applied in solid-phase extraction (SPE) of organic acids, amines and aldehydes, which are important compound families in atmospheric aerosol particles. 1-Alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica was tested as sorbent for SPE for the first time. The analytes were separated and detected by liquid chromatography-mass spectrometry (LC-MS). To confirm the results achieved by LC-MS, the acids were additionally determined by gas chromatography-mass spectrometry (GC-MS). The stability of the IL-functionalized silica materials was tested at low and high pH. The effect of the pH on the extraction was also informative of the retention mechanism of the materials. The results showed anion exchange to be the main interaction, but hydrophobic and π interactions and hydrogen bonding also played a role in the extraction. Extraction efficiencies for organic acids ranged from 87 to 110%, except for cis-pinonic acid (19-29%). Lower extraction efficiencies for amines and aldehydes confirmed that anionic exchange was the predominant interaction. Comparisons made with two commercial SPE materials--silica-based strong anion exchange (SAX) and polymer-based mixed-mode anion exchange and reverse-phase (MAX)--showed the IL-functionalized materials to offer different selectivity and better extraction efficiency than SAX for aromatic compounds. Finally, the new materials were successfully tested in the extraction of an atmospheric aerosol sample.

  7. Novel Aldehyde-Terminated Dendrimers; Synthesis and Cytotoxicity Assay

    PubMed Central

    Hamidi, Aliasghar; Sharifi, Simin; Davaran, Soodabeh; Ghasemi, Saeed; Omidi, Yadollah; Rashidi, Mohammad-Reza

    2012-01-01

    Introduction Polyamidoamine (PAMAM) dendrimers are a unique family of dendritic polymers with numerous pharmaceutical and biomedical applications. One major problem with these polymers is their cytotoxicity. The purpose of this study was to synthesize novel dendrimers with aldehyde terminal groups and compare their cytotoxicity with that of dendri¬mers containing amine-terminated groups. Methods G1(first generation) and G2 (second generation) dendrimers with amine-terminated groups were synthesized by divergent method and then the amine-terminated groups were converted to the aldehyde groups using surface modification of the functional group inversion (FGI) method. The cytotoxicity of the novel G1 and G2 polyamidoaldehyde (PAMAL) dendrimers together with that of G1 and G2 PAMAM-NH2 dendrimers was investigated by MTT assay using MCF-7 cell line. Results The results showed that cytotoxicity of dendrimers with aldehyde-terminated groups is much lower than that of G1 and G2 PAMAM-NH2 dendri¬mers. Conclusion Dendrimers with aldehyde-terminated groups could be used as novel and convenient carriers for drug delivery with low cytotoxic effect compared with the amine-terminated dendrimers. The results revealed that the same generations of the dendri¬mers with aldehyde-terminated groups are far less toxic than the corresponding amine-terminated dendrimers. PMID:23678447

  8. Functional analysis of aldehyde oxidase using expressed chimeric enzyme between monkey and rat.

    PubMed

    Itoh, Kunio; Asakawa, Tasuku; Hoshino, Kouichi; Adachi, Mayuko; Fukiya, Kensuke; Watanabe, Nobuaki; Tanaka, Yorihisa

    2009-01-01

    Aldehyde oxidase (AO) is a homodimer with a subunit molecular mass of approximately 150 kDa. Each subunit consists of about 20 kDa 2Fe-2S cluster domain storing reducing equivalents, about 40 kDa flavine adenine dinucleotide (FAD) domain and about 85 kDa molybdenum cofactor (MoCo) domain containing a substrate binding site. In order to clarify the properties of each domain, especially substrate binding domain, chimeric cDNAs were constructed by mutual exchange of 2Fe-2S/FAD and MoCo domains between monkey and rat. Chimeric monkey/rat AO was referred to one with monkey type 2Fe-2S/FAD domains and a rat type MoCo domain. Rat/monkey AO was vice versa. AO-catalyzed 2-oxidation activities of (S)-RS-8359 were measured using the expressed enzyme in Escherichia coli. Substrate inhibition was seen in rat AO and chimeric monkey/rat AO, but not in monkey AO and chimeric rat/monkey AO, suggesting that the phenomenon might be dependent on the natures of MoCo domain of rat. A biphasic Eadie-Hofstee profile was observed in monkey AO and chimeric rat/monkey AO, but not rat AO and chimeric monkey/rat AO, indicating that the biphasic profile might be related to the properties of MoCo domain of monkey. Two-fold greater V(max) values were observed in monkey AO than in chimeric rat/monkey AO, and in chimeric monkey/rat AO than in rat AO, suggesting that monkey has the more effective electron transfer system than rat. Thus, the use of chimeric enzymes revealed that 2Fe-2S/FAD and MoCo domains affect the velocity and the quantitative profiles of AO-catalyzed (S)-RS-8359 2-oxidation, respectively.

  9. α,β-Unsaturated aldehyde pollutant acrolein suppresses cardiomyocyte contractile function: Role of TRPV1 and oxidative stress.

    PubMed

    Wu, Zhenbiao; He, Emily Y; Scott, Glenda I; Ren, Jun

    2015-01-01

    Air pollution is associated with an increased prevalence of heart disease and is known to trigger a proinflammatory response via stimulation of transient receptor potential vanilloid cation channels (TRPV1, also known as the capsaicin receptor). This study was designed to examine the effect of acrolein, an essential α,β-unsaturated aldehyde pollutant, on myocardial contractile function and the underlying mechanism involved with a focus on TRPV1 and oxidative stress. Cardiomyocyte mechanical and intracellular Ca(2+) properties were evaluated using an IonOptix MyoCam® system including peak shortening (PS), maximal velocity of shortening/relengthening (± dL/dt), time-to-PS (TPS), time-to-90% relengthening (TR90 ), fura-2 fluorescence intensity (FFI) and intracellular Ca(2+) decay. Changes in apoptosis and TRPV1 were evaluated using Western blot analysis. The degree of oxidative stress was assessed using the ratio between reduced and oxidized glutathione. Results obtained revealed that exposure of cardiomyocytes to acrolein acutely compromised contractile and intracellular Ca(2+) properties including depressed PS, ± dL/dt and ΔFFI, as well as prolonged TR90 and intracellular Ca(2+) decay. In addition, acrolein exposure upregulated TRPV1 associated with an increase in both apoptosis and oxidative stress. However, the acrolein-induced cardiomyocyte contractile and intracellular Ca(2+) anomalies, as well as apoptosis (as evidenced by Bcl-2, Bax, FasL, Caspase-3 and -8), were negated by the reactive oxygen species (ROS) scavenger glutathione or the TRPV1 antagonist capsazepine. Collectively these data suggest that the α,β-unsaturated aldehyde pollutant acrolein may play a role in the pathogenesis and sequelae of air pollution-induced heart disease via a TRPV1- and oxidative stress-dependent mechanism.

  10. Unraveling the Concerted Reaction Mechanism of the Noncatalyzed Mukaiyama Reaction between C,O,O-Tris(trimethylsilyl)ketene Acetal and Aldehydes Using Density Functional Theory.

    PubMed

    Hadj Mohamed, Slim; Trabelsi, Mahmoud; Champagne, Benoît

    2016-07-21

    The uncatalyzed Mukaiyama aldol reaction between C,O,O-tris(trimethylsilyl)ketene acetal and aldehydes bearing alkyl, vinyl, and aromatic substituents has been studied theoretically using density functional theory with the M06-2X exchange-correlation functional. These DFT calculations mostly demonstrate that (i) the syn product is both kinetically and thermodynamically favored, (ii) the diastereoselectivity of the uncatalyzed reaction is larger than observed for the reaction catalyzed by HgI2 and it is inverted with respect to the latter, (iii) solvents with larger dielectric constants increase the activation barrier but reduce the diastereoselectivity, (iv) the concerted reaction is preferred over the stepwise reaction, and (v) the OSiMe3 group in geminal lowers the activation barrier and increases the energy of reaction. Analyzing the concerted mechanism unravels four types of cyclic transition states, two pro-anti and two pro-syn. Then, the relative energy of the most stable transition state of each type as well as of the corresponding anti and syn products shows that the syn reaction path is located at lower Gibbs enthalpy than the anti reaction path for all substituents.

  11. Direct enzyme assay evidence confirms aldehyde reductase function of Ydr541cp and Ygl039wp from Saccharomyces cerevisiae.

    PubMed

    Moon, Jaewoong; Liu, Z Lewis

    2015-04-01

    The aldehyde reductase gene ARI1 is a recently characterized member of an intermediate subfamily within the short-chain dehydrogenase/reductase (SDR) superfamily that clarified mechanisms of in situ detoxification of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde by Saccharomyces cerevisiae. Uncharacterized open reading frames (ORFs) are common among tolerant candidate genes identified for lignocellulose-to-advanced biofuels conversion. This study presents partially purified proteins of two ORFs, YDR541C and YGL039W, and direct enzyme assay evidence against aldehyde-inhibitory compounds commonly encountered during lignocellulosic biomass fermentation processes. Each of the partially purified proteins encoded by these ORFs showed a molecular mass of approximately 38 kDa, similar to Ari1p, a protein encoded by aldehyde reductase gene. Both proteins demonstrated strong aldehyde reduction activities toward 14 aldehyde substrates, with high levels of reduction activity for Ydr541cp toward both aromatic and aliphatic aldehydes. While Ydr541cp was observed to have a significantly higher specific enzyme activity at 20 U/mg using co-factor NADPH, Ygl039wp displayed a NADH preference at 25 U/mg in reduction of butylaldehyde. Amino acid sequence analysis identified a characteristic catalytic triad, Ser, Tyr and Lys; a conserved catalytic motif of Tyr-X-X-X-Lys; and a cofactor-binding sequence motif, Gly-X-X-Gly-X-X-Ala, near the N-terminus that are shared by Ydr541cp, Ygl039wp, Yol151wp/GRE2 and Ari1p. Findings of aldehyde reductase genes contribute to the yeast gene annotation and aids development of the next-generation biocatalyst for advanced biofuels production.

  12. Alcohol, Aldehydes, Adducts and Airways

    PubMed Central

    Sapkota, Muna; Wyatt, Todd A.

    2015-01-01

    Drinking alcohol and smoking cigarettes results in the formation of reactive aldehydes in the lung, which are capable of forming adducts with several proteins and DNA. Acetaldehyde and malondialdehyde are the major aldehydes generated in high levels in the lung of subjects with alcohol use disorder who smoke cigarettes. In addition to the above aldehydes, several other aldehydes like 4-hydroxynonenal, formaldehyde and acrolein are also detected in the lung due to exposure to toxic gases, vapors and chemicals. These aldehydes react with nucleophilic targets in cells such as DNA, lipids and proteins to form both stable and unstable adducts. This adduction may disturb cellular functions as well as damage proteins, nucleic acids and lipids. Among several adducts formed in the lung, malondialdehyde DNA (MDA-DNA) adduct and hybrid malondialdehyde-acetaldehyde (MAA) protein adducts have been shown to initiate several pathological conditions in the lung. MDA-DNA adducts are pre-mutagenic in mammalian cells and induce frame shift and base-pair substitution mutations, whereas MAA protein adducts have been shown to induce inflammation and inhibit wound healing. This review provides an insight into different reactive aldehyde adducts and their role in the pathogenesis of lung disease. PMID:26556381

  13. Aldehyde-containing urea-absorbing polysaccharides

    NASA Technical Reports Server (NTRS)

    Mueller, W. A.; Hsu, G. C.; Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A novel aldehyde containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C2 - C3 carbon atoms. By introduction of ether and ester groups onto the pendant primary hydroxyl solubility characteristics are modified. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo.

  14. α,β-Unsaturated aldehyde crotonaldehyde triggers cardiomyocyte contractile dysfunction: role of TRPV1 and mitochondrial function.

    PubMed

    Pei, Zhaohui; Zhuang, Zhiqiang; Sang, Hanfei; Wu, Zhenbiao; Meng, Rongsen; He, Emily Y; Scott, Glenda I; Maris, Jackie R; Li, Ruiman; Ren, Jun

    2014-04-01

    Recent evidence has suggested that cigarette smoking is associated with an increased prevalence of heart diseases. Given that cigarette smoking triggers proinflammatory response via stimulation of the capsaicin-sensitive transient receptor potential cation channel TRPV1, this study was designed to evaluate the effect of an essential α,β-unsaturated aldehyde from cigarette smoke crotonaldehyde on myocardial function and the underlying mechanism with a focus on TRPV1 and mitochondria. Cardiomyocyte mechanical and intracellular Ca2+ properties were evaluated including peak shortening (PS), maximal velocity of shortening/relengthening (±dL/dt), time-to-PS (TPS), time-to-90% relengthening (TR90), fura-2 fluorescence intensity (FFI), intracellular Ca2+ decay and SERCA activity. Apoptosis and TRPV1 were evaluated using Western blot analysis. Production of reactive oxygen species (ROS) and DNA damage were measured using the intracellular fluoroprobe 5-(6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate and 8-hydroxy-2'-deoxyguanosine (8-OHdG), respectively. Our data revealed that crotonaldehyde interrupted cardiomyocyte contractile and intracellular Ca2+ property including depressed PS, ±dL/dt, ΔFFI and SERCA activity, as well as prolonged TR90 and intracellular Ca2+ decay. Crotonaldehyde exposure increased TRPV1 and NADPH oxidase levels, promoted apoptosis, mitochondrial injury (decreased aconitase activity, PGC-1α and UCP-2) as well as production of ROS and 8-OHdG. Interestingly, crotonaldehyde-induced cardiac defect was obliterated by the ROS scavenger glutathione and the TRPV1 inhibitor capsazepine. Capsazepine (not glutathione) ablated crotonaldehyde-induced mitochondrial damage. Capsazepine, glutathione and the NADPH inhibitor apocynin negated crotonaldehyde-induced ROS accumulation. Our data suggest a role of crotonaldehyde compromises cardiomyocyte mechanical function possibly through a TRPV1- and mitochondria-dependent oxidative stress mechanism.

  15. Immobilisation and characterisation of biocatalytic co-factor recycling enzymes, glucose dehydrogenase and NADH oxidase, on aldehyde functional ReSyn™ polymer microspheres.

    PubMed

    Twala, Busisiwe V; Sewell, B Trevor; Jordaan, Justin

    2012-05-10

    The use of enzymes in industrial applications is limited by their instability, cost and difficulty in their recovery and re-use. Immobilisation is a technique which has been shown to alleviate these limitations in biocatalysis. Here we describe the immobilisation of two biocatalytically relevant co-factor recycling enzymes, glucose dehydrogenase (GDH) and NADH oxidase (NOD) on aldehyde functional ReSyn™ polymer microspheres with varying functional group densities. The successful immobilisation of the enzymes on this new high capacity microsphere technology resulted in the maintenance of activity of ∼40% for GDH and a maximum of 15.4% for NOD. The microsphere variant with highest functional group density of ∼3500 μmol g⁻¹ displayed the highest specific activity for the immobilisation of both enzymes at 33.22 U mg⁻¹ and 6.75 U mg⁻¹ for GDH and NOD with respective loading capacities of 51% (0.51 mg mg⁻¹) and 129% (1.29 mg mg⁻¹). The immobilised GDH further displayed improved activity in the acidic pH range. Both enzymes displayed improved pH and thermal stability with the most pronounced thermal stability for GDH displayed on ReSyn™ A during temperature incubation at 65 °C with a 13.59 fold increase, and NOD with a 2.25-fold improvement at 45 °C on the same microsphere variant. An important finding is the suitability of the microspheres for stabilisation of the multimeric protein GDH.

  16. Direct enzyme assay evidence confirms aldehyde reductase function of Ydr541cp and Ygl039wp from Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aldehyde reductase gene ARI1 is a recently characterized member of intermediate subfamily under SDR (short-chain dehydrogenase/reductase) superfamily that revealed mechanisms of in situ detoxification of furfural and HMF for tolerance of Saccharomyces cerevisiae. Uncharacterized open reading frames ...

  17. Click with a boronic acid handle: a neighboring group-assisted click reaction that allows ready secondary functionalization.

    PubMed

    Draganov, Alexander B; Wang, Ke; Holmes, Jalisa; Damera, Krishna; Wang, Danzhu; Dai, Chaofeng; Wang, Binghe

    2015-10-21

    The feasibility of a neighboring boronic acid-facilitated facile condensation of an aldehyde is described. This reaction is bio-orthogonal, complete at room temperature within minutes, and suitable for bioconjugation chemistry. The boronic acid group serves the dual purpose of catalyzing the condensation reaction and being a handle for secondary functionalization.

  18. Direct Access to β-Fluorinated Aldehydes by Nitrite-Modified Wacker Oxidation.

    PubMed

    Chu, Crystal K; Ziegler, Daniel T; Carr, Brian; Wickens, Zachary K; Grubbs, Robert H

    2016-07-11

    An aldehyde-selective Wacker-type oxidation of allylic fluorides proceeds with a nitrite catalyst. The method represents a direct route to prepare β-fluorinated aldehydes. Allylic fluorides bearing a variety of functional groups are transformed in high yield and very high regioselectivity. Additionally, the unpurified aldehyde products serve as versatile intermediates, thus enabling access to a diverse array of fluorinated building blocks. Preliminary mechanistic investigations suggest that inductive effects have a strong influence on the rate and regioselectivity of the oxidation.

  19. Expression of aldehyde dehydrogenase family 1 member A1 and high mobility group box 1 in oropharyngeal squamous cell carcinoma in association with survival time

    PubMed Central

    Qian, Xu; Coordes, Annekatrin; Kaufmann, Andreas M.; Albers, Andreas E.

    2016-01-01

    Despite the development of novel multimodal treatment combinations in advanced oropharyngeal squamous cell carcinoma (OSCC), outcomes remain poor. The identification of specifically validated biomarkers is required to understand the underlying molecular mechanisms, to evaluate treatment efficiency and to develop novel therapeutic targets. The present study, therefore, examined the presence of aldehyde dehydrogenase family 1 member A1 (ALDH1A1) and high mobility group box 1 (HMGB1) expression in primary OSCC and analyzed the impact on survival time. In 59 patients with OSCC, the expression of ALDH1A1, p16 and HMGB1, and their clinicopathological data were analyzed. HMGB1 positivity was significantly increased in patients with T1-2 stage disease compared with T3-4 stage disease (P<0.001), whereas ALDH1A1 positivity was not. ALDH1A1+ tumors showed significantly lower differentiation than ALDH1A1− tumors (P=0.018). Multivariate analysis showed that ALDH1A1 positivity (P=0.041) and nodal status (N2-3) (P=0.036) predicted a poor prognosis. In this patient cohort, ALDH1A1 and nodal status were identified as independent predictors of a shorter overall survival time. The study results, therefore, provide evidence of the prognostic value of ALDH1A1 as a marker for cancer stem cells and nodal status in OSCC patients. PMID:27900016

  20. Expression of aldehyde dehydrogenase family 1 member A1 and high mobility group box 1 in oropharyngeal squamous cell carcinoma in association with survival time.

    PubMed

    Qian, Xu; Coordes, Annekatrin; Kaufmann, Andreas M; Albers, Andreas E

    2016-11-01

    Despite the development of novel multimodal treatment combinations in advanced oropharyngeal squamous cell carcinoma (OSCC), outcomes remain poor. The identification of specifically validated biomarkers is required to understand the underlying molecular mechanisms, to evaluate treatment efficiency and to develop novel therapeutic targets. The present study, therefore, examined the presence of aldehyde dehydrogenase family 1 member A1 (ALDH1A1) and high mobility group box 1 (HMGB1) expression in primary OSCC and analyzed the impact on survival time. In 59 patients with OSCC, the expression of ALDH1A1, p16 and HMGB1, and their clinicopathological data were analyzed. HMGB1 positivity was significantly increased in patients with T1-2 stage disease compared with T3-4 stage disease (P<0.001), whereas ALDH1A1 positivity was not. ALDH1A1(+) tumors showed significantly lower differentiation than ALDH1A1(-) tumors (P=0.018). Multivariate analysis showed that ALDH1A1 positivity (P=0.041) and nodal status (N2-3) (P=0.036) predicted a poor prognosis. In this patient cohort, ALDH1A1 and nodal status were identified as independent predictors of a shorter overall survival time. The study results, therefore, provide evidence of the prognostic value of ALDH1A1 as a marker for cancer stem cells and nodal status in OSCC patients.

  1. A Functional Analytic Approach to Group Psychotherapy

    ERIC Educational Resources Information Center

    Vandenberghe, Luc

    2009-01-01

    This article provides a particular view on the use of Functional Analytical Psychotherapy (FAP) in a group therapy format. This view is based on the author's experiences as a supervisor of Functional Analytical Psychotherapy Groups, including groups for women with depression and groups for chronic pain patients. The contexts in which this approach…

  2. Ultra-high olfactory sensitivity for the human sperm-attractant aromatic aldehyde bourgeonal in CD-1 mice.

    PubMed

    Larsson, Linda; Laska, Matthias

    2011-12-01

    Recent studies have shown that certain aromatic aldehydes are ligands for olfactory receptors expressed in mammalian sperm cells and induce sperm chemotaxis. Using a conditioning paradigm, the olfactory sensitivity of five CD-1 mice for seven aromatic aldehydes was investigated. With all seven stimuli, the mice discriminated concentrations as low as 0.01 ppm (parts per million) from the solvent, and with bourgeonal the animals even detected concentrations as low as 0.1 ppq (parts per quadrillion) which constitutes the lowest olfactory detection threshold value reported in this species so far. The presence of a tertiary butyl group in para-position (relative to the functional aldehyde group) combined with a lack of an additional alkyl group next to the functional aldehyde group may be responsible for the extraordinary sensitivity of the mice for bourgeonal.

  3. Nonaggregating Microspheres Containing Aldehyde Groups

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan

    1989-01-01

    Cobalt gamma irradiation of hydrophilic monomers in presence of acrolein yields exceptionally-stable, nonaggregating microspheres. Mixtures of 2-hydroxyethyl methacrylate (HEMA) and acrolein form homogeneous solutions in distilled water containing 0.4 percent polyethylene oxide (PEO). After deaeration with nitrogen, mixtures irradiated at room temperature with gamma rays from cobalt source; total exposure time 4 hours, at rate of 0.2 milliroentgen per hour. Reaction product centrifuged three times for purification and kept in distilled water.

  4. Relating Functional Groups to the Periodic Table

    ERIC Educational Resources Information Center

    Struyf, Jef

    2009-01-01

    An introduction to organic chemistry functional groups and their ionic variants is presented. Functional groups are ordered by the position of their specific (hetero) atom in the periodic table. Lewis structures are compared with their corresponding condensed formulas. (Contains 5 tables.)

  5. Silsesquioxane nanoparticles with reactive internal functional groups

    NASA Astrophysics Data System (ADS)

    Brozek, Eric M.; Washton, Nancy M.; Mueller, Karl T.; Zharov, Ilya

    2017-02-01

    A series of silsesquioxane nanoparticles containing reactive internal organic functionalities throughout the entire particle body have been synthesized using a surfactant-free method with organosilanes as the sole precursors and a base catalyst. The organic functional groups incorporated are vinyl, allyl, mercapto, cyanoethyl, and cyanopropyl groups. The sizes and morphologies of the particles were characterized using SEM and nitrogen adsorption, while the compositions were confirmed using TGA, FT-IR, solid state NMR, and elemental analysis. The accessibility and reactivity of the functional groups inside the particles were demonstrated by performing bromination and reduction reactions in the interior of the particles.

  6. A Novel Aldehyde Dehydrogenase-3 Activator (Alda-89) Protects Submandibular Gland Function from Irradiation without Accelerating Tumor Growth

    PubMed Central

    Xiao, Nan; Cao, Hongbin; Chen, Che-Hong; Kong, Christina S.; Ali, Rehan; Chan, Cato; Sirjani, Davud; Graves, Edward; Koong, Albert; Giaccia, Amato; Mochly-Rosen, Daria; Le, Quynh-Thu

    2013-01-01

    Purpose To determine the effect of Alda-89 (an ALDH3 activitor) on (1) the function of irradiated (RT) submandibular gland (SMG) in mice, (2) its toxicity profile and (3) its effect on the growth of head and neck cancer (HNC) in vitro and in vivo. Experimental Design Adult mice were infused with Alda-89 or vehicle before, during and after RT. Saliva secretion was monitored weekly. Hematology, metabolic profile and post-mortem evaluation for toxicity were examined at the time of sacrifice. Alda-89 or vehicle was applied to HNC cell lines in vitro, and SCID mice transplanted with HNC in vivo with or without radiation; HNC growth was monitored. The ALDH3A1 and ALDH3A2 protein expression was evaluated in 89 HNC patients and correlated to freedom from relapse (FFR) and overall survival (OS). Results Alda-89 infusion significantly resulted in more whole saliva production and a higher percentage of preserved acini after RT compared to vehicle control. There was no difference in the complete blood count, metabolic profile, and major organ morphology between the Alda-89 and vehicle groups. Compared to vehicle control, Alda-89 treatment did not accelerate HNC cell proliferation in vitro, nor did it affect tumor growth in vivo with or without RT. Higher expression of ALDH3A1 or ALDH3A2 was not significantly associated with worse FFR or OS in either HPV-positive or HPV-negative group. Conclusion Alda-89 preserves salivary function after RT without affecting HNC growth or causing measurable toxicity in mice. It is a promising candidate to mitigate RT-related xerostomia. PMID:23812668

  7. Microbial Engineering for Aldehyde Synthesis

    PubMed Central

    Kunjapur, Aditya M.

    2015-01-01

    Aldehydes are a class of chemicals with many industrial uses. Several aldehydes are responsible for flavors and fragrances present in plants, but aldehydes are not known to accumulate in most natural microorganisms. In many cases, microbial production of aldehydes presents an attractive alternative to extraction from plants or chemical synthesis. During the past 2 decades, a variety of aldehyde biosynthetic enzymes have undergone detailed characterization. Although metabolic pathways that result in alcohol synthesis via aldehyde intermediates were long known, only recent investigations in model microbes such as Escherichia coli have succeeded in minimizing the rapid endogenous conversion of aldehydes into their corresponding alcohols. Such efforts have provided a foundation for microbial aldehyde synthesis and broader utilization of aldehydes as intermediates for other synthetically challenging biochemical classes. However, aldehyde toxicity imposes a practical limit on achievable aldehyde titers and remains an issue of academic and commercial interest. In this minireview, we summarize published efforts of microbial engineering for aldehyde synthesis, with an emphasis on de novo synthesis, engineered aldehyde accumulation in E. coli, and the challenge of aldehyde toxicity. PMID:25576610

  8. Amino group combined P/Ge and P/Sn Lewis pairs: synthesis and dipolar addition reactions to alkyne and aldehyde molecules.

    PubMed

    Yu, Ying; Li, Jiancheng; Liu, Weiping; Ye, Qingsong; Zhu, Hongping

    2016-04-14

    Amino group combined P/Ge-based frustrated Lewis pairs (FLPs) Ph2PN(R)GeCl3 (R = 2,6-iPr2C6H3 (1), 2,4,6-Me3C6H2 (2), and C6H11 (3)) and Ph2PN(2,6-iPr2C6H3)GeMe3 (4) as well as P/Sn-based FLP Ph2PN(2,6-iPr2C6H3)SnMe3 (5) were prepared and utilized for reactions with alkyne and aldehyde molecules. Compounds 1-3 each reacted with MeO2CC[triple bond, length as m-dash]CCO2Me to give zwitterionic cyclic vinyls [Ph2PN(R)GeCl3](MeO2CC[double bond, length as m-dash]CCO2Me) (6-8) and compound 1 reacted with HC[triple bond, length as m-dash]CCO2Me to give the similar compound [Ph2PN(2,4,6-Me3C6H2)GeCl3](HC[double bond, length as m-dash]CCO2Me) (9). Compound 4 reacted with RC[triple bond, length as m-dash]CCO2Me to afford acyclic vinyls 2,6-iPr2C6H3N[double bond, length as m-dash]P(Ph2)C(R)[double bond, length as m-dash]C(CO2Me)GeMe3 (R = CO2Me (10), H (11)) and 5 reacted with MeO2CC[triple bond, length as m-dash]CCO2Me to give 2,6-iPr2C6H3N[double bond, length as m-dash]P(Ph2)C(CO2Me)[double bond, length as m-dash]C(CO2Me)SnMe3 (12). The reactions of 1 with CH3CH2CHO and 1,4-(CHO)2C6H4 were also investigated and yielded novel zwitterionic OCPNGe five-heteroatom cycles [Ph2PN(2,6-iPr2C6H3)GeCl3][CH(CH2CH3)O] (13) and [Ph2PN(2,6-iPr2C6H3)GeCl3][p-(OCH)C6H4CHO][Cl3GeN(2,6-iPr2C6H3)PPh2] (14). Compounds 1-14 were characterized by NMR ((1)H, (13)C, and (31)P) and CHN elemental analysis, of which 1, 7, and 10-14 were further studied by X-ray crystallography. The reactions of 4 (or 5) with RC[triple bond, length as m-dash]CCO2Me to produce 10-12 present a novel way of obtaining the germyl (or stannyl) and iminophosphoranyl co-substituted vinyls.

  9. Group entropies, correlation laws, and zeta functions

    NASA Astrophysics Data System (ADS)

    Tempesta, Piergiulio

    2011-08-01

    The notion of group entropy is proposed. It enables the unification and generaliztion of many different definitions of entropy known in the literature, such as those of Boltzmann-Gibbs, Tsallis, Abe, and Kaniadakis. Other entropic functionals are introduced, related to nontrivial correlation laws characterizing universality classes of systems out of equilibrium when the dynamics is weakly chaotic. The associated thermostatistics are discussed. The mathematical structure underlying our construction is that of formal group theory, which provides the general structure of the correlations among particles and dictates the associated entropic functionals. As an example of application, the role of group entropies in information theory is illustrated and generalizations of the Kullback-Leibler divergence are proposed. A new connection between statistical mechanics and zeta functions is established. In particular, Tsallis entropy is related to the classical Riemann zeta function.

  10. Identifying copepod functional groups from species functional traits

    PubMed Central

    Benedetti, Fabio; Gasparini, Stéphane; Ayata, Sakina-Dorothée

    2016-01-01

    We gathered information on the functional traits of the most representative copepod species in the Mediterranean Sea. Our database includes 191 species described by 7 traits encompassing diverse ecological functions: minimal and maximal body length, trophic group, feeding type, spawning strategy, diel vertical migration and vertical habitat. Cluster analysis in the functional trait space revealed that Mediterranean copepods can be separated into groups with distinct ecological roles. PMID:26811565

  11. Stereodivergent Coupling of Aldehydes and Alkynes via Synergistic Catalysis Using Rh and Jacobsen's Amine.

    PubMed

    Cruz, Faben A; Dong, Vy M

    2017-01-25

    We report an enantioselective coupling between α-branched aldehydes and alkynes to generate vicinal quaternary and tertiary carbon stereocenters. The choice of Rh and organocatalyst combination allows for access to all possible stereoisomers with high enantio-, diastereo-, and regioselectivity. Our study highlights the power of catalysis to activate two common functional groups and provide access to divergent stereoisomers and constitutional structures.

  12. Functional Group Chemistry (by James R. Hanson)

    NASA Astrophysics Data System (ADS)

    Karty, Joel M.

    2002-06-01

    Given its density and brevity and the apparent requirement of previous organic chemistry knowledge, Functional Group Chemistry is inappropriate as a stand-alone text for first-year organic students. It is also difficult to imagine using it as a supplement to a traditional textbook, since the textbook would presumably provide the same material in greater depth and with better clarity. The end-of-chapter problems in Functional Group Chemistry, however, would provide excellent exam and supplemental homework questions, and would be appropriate given the greater emphasis on reaction mechanisms in the traditional textbook. Perhaps the best use for Functional Group Chemistry, then, is for students returning after having had a year of organic chemistry, either for a quick reference, or for an in-depth review in studying for a standardized exam.

  13. New preparation of diethyl methylformylphosphonate dimethylhydrazone: A reagent for aldehyde homologation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phosphonate reagent, diethyl methylformyl-2-phosphonate dimethylhydrazone contains a protected aldehyde group instead of the usual ester group. It can be used for the two-carbon homologation of aldehydes to a, ß-unsaturated aldehydes. The reagent can be prepared in good overall yield (82%) and...

  14. Antibiotics from basidiomycetes. 26. Phlebiakauranol aldehyde an antifungal and cytotoxic metabolite from Punctularia atropurpurascens.

    PubMed

    Anke, H; Casser, I; Steglich, W; Pommer, E H

    1987-04-01

    Phlebiakauranol aldehyde and the corresponding alcohol were isolated from cultures of Punctularia atropurpurascens. The aldehyde but not the alcohol exhibited strong antifungal activity against several phytopathogens as well as antibacterial and cytotoxic activities. Two acetylated derivatives prepared from the aldehyde showed only very weak antifungal and antibacterial and moderate cytotoxic activities. We therefore assume, that the aldehyde group together with the high number of hydroxyl groups are responsible for the biological activity of the compound.

  15. Molecular Mechanisms of Aldehyde Toxicity: A Chemical Perspective

    PubMed Central

    2015-01-01

    Aldehydes are electrophilic compounds to which humans are pervasively exposed. Despite a significant health risk due to exposure, the mechanisms of aldehyde toxicity are poorly understood. This ambiguity is likely due to the structural diversity of aldehyde derivatives and corresponding differences in chemical reactions and biological targets. To gain mechanistic insight, we have used parameters based on the hard and soft, acids and bases (HSAB) theory to profile the different aldehyde subclasses with respect to electronic character (softness, hardness), electrophilic reactivity (electrophilic index), and biological nucleophilic targets. Our analyses indicate that short chain aldehydes and longer chain saturated alkanals are hard electrophiles that cause toxicity by forming adducts with hard biological nucleophiles, e.g., primary nitrogen groups on lysine residues. In contrast, α,β-unsaturated carbonyl derivatives, alkenals, and the α-oxoaldehydes are soft electrophiles that preferentially react with soft nucleophilic thiolate groups on cysteine residues. The aldehydes can therefore be grouped into subclasses according to common electronic characteristics (softness/hardness) and molecular mechanisms of toxicity. As we will discuss, the toxic potencies of these subgroups are generally related to corresponding electrophilicities. For some aldehydes, however, predictions of toxicity based on electrophilicity are less accurate due to inherent physicochemical variables that limit target accessibility, e.g., steric hindrance and solubility. The unsaturated aldehydes are also members of the conjugated type-2 alkene chemical class that includes α,β-unsaturated amide, ketone, and ester derivatives. Type-2 alkenes are electrophiles of varying softness and electrophilicity that share a common mechanism of toxicity. Therefore, exposure to an environmental mixture of unsaturated carbonyl derivatives could cause “type-2 alkene toxicity” through additive interactions

  16. Identification and Characterization of an Antennae-Specific Aldehyde Oxidase from the Navel Orangeworm

    PubMed Central

    Choo, Young-Moo; Pelletier, Julien; Atungulu, Elizabeth; Leal, Walter S.

    2013-01-01

    Antennae-specific odorant-degrading enzymes (ODEs) are postulated to inactivate odorant molecules after they convey their signal. Different classes of insect ODEs are specific to esters, alcohols, and aldehydes – the major functional groups of female-produced, hydrophobic sex pheromones from moth species. Esterases that rapidly inactive acetate and other esters have been well-studied, but less is known about aldehyde oxidases (AOXs). Here we report cloning of an aldehyde oxidase, AtraAOX2, from the antennae of the navel orangeworm (NOW), Amyelois transitella, and the first activity characterization of a recombinant insect AOX. AtraAOX2 gene spans 3,813 bp and encodes a protein with 1,270 amino acid residues. AtraAOX2 cDNA was expressed in baculovirus-infected insect Sf21 cells as a ≈280 kDa homodimer with 140 kDa subunits. Recombinant AtraAOX2 degraded Z11Z13–16Ald and plant volatile aldehydes as substrates. However, as expected for aldehyde oxidases, recombinant AtraAOX2 did not show specificity for Z11Z13–16Ald, the main constituent of the sex pheromone, but showed high activity for plant volatile aldehydes. Our data suggest AtraAOX2 might be involved in degradation of a diversity of aldehydes including sex pheromones, plant-derived semiochemicals, and chemical cues for oviposition sites. Additionally, AtraAOX2 could protect the insect's olfactory system from xenobiotics, including pesticides that might reach the sensillar lymph surrounding the olfactory receptor neurons. PMID:23826341

  17. Antibiotic inhibition of group I ribozyme function.

    PubMed

    von Ahsen, U; Davies, J; Schroeder, R

    1991-09-26

    The discovery of catalytically active RNA has provided the basis for the evolutionary concept of an RNA world. It has been proposed that during evolution the functions of ancient catalytic RNA were modulated by low molecular weight effectors, related to antibiotics, present in the primordial soup. Antibiotics and RNA may have coevolved in the formation of the modern ribosome. Here we report that a set of aminoglycoside antibiotics, which are known to interact with the decoding region of the 16S ribosomal RNA of Escherichia coli, inhibit the second step of splicing of the T4 phage-derived td intron. Thus catalytic RNA seems to interact not only with a mononucleotide and an amino acid, but also with another class of biomolecules, the sugars. Splicing of other group I introns but not group II introns was inhibited. The similarity in affinity and specificity of these antibiotics for group I introns and rRNAs may result from recognition of evolutionarily conserved structures.

  18. The methyl group as a source of structural diversity in heterocyclic chemistry: side chain functionalization of picolines and related heterocycles.

    PubMed

    Mamane, Victor; Aubert, Emmanuel; Fort, Yves

    2007-09-14

    The reaction of 2-picoline at the methyl group with NDA and KDA followed by dimethyldisulfide trapping furnished, respectively, dithioacetals and trithioortho esters with high selectivity. The method was successfully applied to other methyl-substituted pyridines, quinolines, and pyrazines. Dithioketals were prepared by a one-pot procedure involving the reaction of metalated 2-picoline with 2 equiv of dimethyldisulfide followed by in situ trapping with a second electrophile. All of the generated thio-substituted compounds were efficiently transformed in presence of mercury salts or under oxidizing conditions to other functional groups comprising aldehydes, ketones, ketals, thiol esters, orthoesters, and esters.

  19. Structural and functional consequences of coenzyme binding to the inactive asian variant of mitochondrial aldehyde dehydrogenase: roles of residues 475 and 487.

    PubMed

    Larson, Heather N; Zhou, Jianzhong; Chen, Zhiqiang; Stamler, Jonathan S; Weiner, Henry; Hurley, Thomas D

    2007-04-27

    The common mitochondrial aldehyde dehydrogenase (ALDH2) ALDH2(*)2 polymorphism is associated with impaired ethanol metabolism and decreased efficacy of nitroglycerin treatment. These physiological effects are due to the substitution of Lys for Glu-487 that reduces the k(cat) for these processes and increases the K(m) for NAD(+), as compared with ALDH2. In this study, we sought to understand the nature of the interactions that give rise to the loss of structural integrity and low activity in ALDH2(*)2 even when complexed with coenzyme. Consequently, we have solved the crystal structure of ALDH2(*)2 complexed with coenzyme to 2.5A(.) We have also solved the structures of a mutated form of ALDH2 where Arg-475 is replaced by Gln (R475Q). The structural and functional properties of the R475Q enzyme are intermediate between those of wild-type and the ALDH2(*)2 enzymes. In both cases, the binding of coenzyme restores most of the structural deficits observed in the apoenzyme structures. The binding of coenzyme to the R475Q enzyme restores its structure and catalytic properties to near wild-type levels. In contrast, the disordered helix within the coenzyme binding pocket of ALDH2(*)2 is reordered, but the active site is only partially reordered. Consistent with the structural data, ALDH2(*)2 showed a concentration-dependent increase in esterase activity and nitroglycerin reductase activity upon addition of coenzyme, but the levels of activity do not approach those of the wild-type enzyme or that of the R475Q enzyme. The data presented shows that Glu-487 maintains a critical function in linking the structure of the coenzyme-binding site to that of the active site through its interactions with Arg-264 and Arg-475, and in doing so, creates the stable structural scaffold conducive to catalysis.

  20. Structural and Functional Consequences of Coenzyme Binding to the Inactive Asian Variant of Mitochondrial Aldehyde Dehydrogenase: Roles of Residues 475 and 487

    SciTech Connect

    Larson,H.; Zhou, J.; Chen, Z.; Stamler, J.; Weiner, H.; Hurley, T.

    2007-01-01

    The common mitochondrial aldehyde dehydrogenase (ALDH2) ALDH2*2 polymorphism is associated with impaired ethanol metabolism and decreased efficacy of nitroglycerin treatment. These physiological effects are due to the substitution of Lys for Glu-487 that reduces the k{sub cat} for these processes and increases the K{sub m} for NAD{sup +}, as compared with ALDH2. In this study, we sought to understand the nature of the interactions that give rise to the loss of structural integrity and low activity in ALDH2*2 even when complexed with coenzyme. Consequently, we have solved the crystal structure of ALDH2*2 complexed with coenzyme to 2.5 {angstrom}. We have also solved the structures of a mutated form of ALDH2 where Arg-475 is replaced by Gln (R475Q). The structural and functional properties of the R475Q enzyme are intermediate between those of wild-type and the ALDH2*2 enzymes. In both cases, the binding of coenzyme restores most of the structural deficits observed in the apoenzyme structures. The binding of coenzyme to the R475Q enzyme restores its structure and catalytic properties to near wild-type levels. In contrast, the disordered helix within the coenzyme binding pocket of ALDH2*2 is reordered, but the active site is only partially reordered. Consistent with the structural data, ALDH2*2 showed a concentration-dependent increase in esterase activity and nitroglycerin reductase activity upon addition of coenzyme, but the levels of activity do not approach those of the wild-type enzyme or that of the R475Q enzyme. The data presented shows that Glu-487 maintains a critical function in linking the structure of the coenzyme binding site to that of the active site through its interactions with Arg-264 and Arg-475, and in doing so, creates the stable structural scaffold conducive to catalysis.

  1. Functional renormalization group in Floquet space

    NASA Astrophysics Data System (ADS)

    Eissing, Anna Katharina; Meden, Volker; Kennes, Dante Marvin

    2016-12-01

    We present an extension of the functional renormalization group to Floquet space, which enables us to treat the long time behavior of interacting time periodically driven quantum dots. It is one of its strength that the method is neither bound to small driving amplitudes nor to small driving frequencies, i.e., very general time periodic signals can be considered. It is applied to the interacting resonant level model, a prototype model of a spinless, fermionic quantum dot. The renormalization in several setups with different combinations of time periodic parameters is studied, where the numerical results are complemented by analytic expressions for the renormalization in the limit of small driving amplitude. We show how the driving frequency acts as an infrared cutoff of the underlying renormalization group flow which manifests in novel power laws. We utilize the tunability of the effective reservoir distribution function in a periodically driven onsite energy setup to show how its shape is directly reflected in the renormalization group flow. This allows us to flexibly tune the power-law renormalization generically encountered in quantum dot structures. Finally, an in-phase quantum pump as well as a single parameter pump are investigated in the whole regime of driving frequency, demonstrating that the new power law in the driving frequency is reflected in the mean current of the latter.

  2. Electron transmission through a class of anthracene aldehyde molecules

    NASA Astrophysics Data System (ADS)

    Petreska, Irina; Ohanesjan, Vladimir; Pejov, Ljupco; Kocarev, Ljupco

    2016-03-01

    Transmission of electrons via metal-molecule-metal junctions, involving rotor-stator anthracene aldehyde molecules is investigated. Two model barriers having input parameters evaluated from accurate ab initio calculations are proposed and the transmission coefficients are obtained by using the quasiclassical approximation. Transmission coefficients further enter in the integral for the net current, utilizing Simmons' method. Conformational dependence of the tunneling processes is evident and the presence of the side groups enhances the functionality of the future single-molecule based electronic devices.

  3. Aldehyde-stabilized cryopreservation.

    PubMed

    McIntyre, Robert L; Fahy, Gregory M

    2015-12-01

    We describe here a new cryobiological and neurobiological technique, aldehyde-stabilized cryopreservation (ASC), which demonstrates the relevance and utility of advanced cryopreservation science for the neurobiological research community. ASC is a new brain-banking technique designed to facilitate neuroanatomic research such as connectomics research, and has the unique ability to combine stable long term ice-free sample storage with excellent anatomical resolution. To demonstrate the feasibility of ASC, we perfuse-fixed rabbit and pig brains with a glutaraldehyde-based fixative, then slowly perfused increasing concentrations of ethylene glycol over several hours in a manner similar to techniques used for whole organ cryopreservation. Once 65% w/v ethylene glycol was reached, we vitrified brains at -135 °C for indefinite long-term storage. Vitrified brains were rewarmed and the cryoprotectant removed either by perfusion or gradual diffusion from brain slices. We evaluated ASC-processed brains by electron microscopy of multiple regions across the whole brain and by Focused Ion Beam Milling and Scanning Electron Microscopy (FIB-SEM) imaging of selected brain volumes. Preservation was uniformly excellent: processes were easily traceable and synapses were crisp in both species. Aldehyde-stabilized cryopreservation has many advantages over other brain-banking techniques: chemicals are delivered via perfusion, which enables easy scaling to brains of any size; vitrification ensures that the ultrastructure of the brain will not degrade even over very long storage times; and the cryoprotectant can be removed, yielding a perfusable aldehyde-preserved brain which is suitable for a wide variety of brain assays.

  4. Characterization of five fatty aldehyde dehydrogenase enzymes from Marinobacter and Acinetobacter: structural insights into the aldehyde binding pocket.

    PubMed

    Bertram, Jonathan H; Mulliner, Kalene M; Shi, Ke; Plunkett, Mary H; Nixon, Peter; Serratore, Nicholas A; Douglas, Christopher J; Aihara, Hideki; Barney, Brett M

    2017-04-07

    Enzymes involved in lipid biosynthesis and metabolism play an important role in energy conversion and storage, and in the function of structural components such as cell membranes. The fatty aldehyde dehydrogenase (FAldDH) plays a central function in the metabolism of lipid intermediates, oxidizing fatty aldehydes to the corresponding fatty acid, and competing with pathways that would further reduce the fatty aldehydes to fatty alcohols or require the fatty aldehydes to produce alkanes. In this report, the genes for four putative FAldDH enzymes from Marinobacter aquaeolei VT8 and an additional enzyme from Acinetobacter baylyi were heterologously expressed in Escherichia coli and shown to display FAldDH activity. Five enzymes (Maqu_0438, Maqu_3316, Maqu_3410, Maqu_3572 and WP_004927398) were found to act on aldehydes ranging from acetaldehyde to hexadecanal, and also acted on the unsaturated long-chain palmitoleyl and oleyl aldehydes. A comparison of the specificity of these enzymes with various aldehydes is presented. Crystallization trials yielded diffraction quality crystals of one particular FAldDH (Maqu_3316) from M. aquaeolei VT8. Crystals were independently treated with both the NAD(+) cofactor and the aldehyde substrate decanal, revealing specific details of the likely substrate binding pocket for this class of enzymes. A likely model for how the catalysis by the enzyme is accomplished is also provided.Importance: This study provides a comparison of multiple enzymes with the ability to oxidize fatty aldehydes to fatty acids, and provides a likely picture of how the fatty aldehyde and NAD(+) is bound to the enzyme to facilitate catalysis. Based on the information obtained from this structural analysis and the comparisons of specificity for the five enzymes that were characterized, correlations may be drawn to the potential roles played by specific residues within the structure.

  5. The First Mammalian Aldehyde Oxidase Crystal Structure

    PubMed Central

    Coelho, Catarina; Mahro, Martin; Trincão, José; Carvalho, Alexandra T. P.; Ramos, Maria João; Terao, Mineko; Garattini, Enrico; Leimkühler, Silke; Romão, Maria João

    2012-01-01

    Aldehyde oxidases (AOXs) are homodimeric proteins belonging to the xanthine oxidase family of molybdenum-containing enzymes. Each 150-kDa monomer contains a FAD redox cofactor, two spectroscopically distinct [2Fe-2S] clusters, and a molybdenum cofactor located within the protein active site. AOXs are characterized by broad range substrate specificity, oxidizing different aldehydes and aromatic N-heterocycles. Despite increasing recognition of its role in the metabolism of drugs and xenobiotics, the physiological function of the protein is still largely unknown. We have crystallized and solved the crystal structure of mouse liver aldehyde oxidase 3 to 2.9 Å. This is the first mammalian AOX whose structure has been solved. The structure provides important insights into the protein active center and further evidence on the catalytic differences characterizing AOX and xanthine oxidoreductase. The mouse liver aldehyde oxidase 3 three-dimensional structure combined with kinetic, mutagenesis data, molecular docking, and molecular dynamics studies make a decisive contribution to understand the molecular basis of its rather broad substrate specificity. PMID:23019336

  6. A Theoretical Study of the Methyl and Aldehyde Torsion FIR Spectra in Symmetric Propanal Isotopomers

    NASA Astrophysics Data System (ADS)

    Smeyers, Y. G.; Villa, M.; Uc, V. H.; Vivier-Bunge, A.

    2000-05-01

    This paper is an extension of the techniques developed by us [A. Vivier-Bunge, V. H. Uc, and Y. G. Smeyers, J. Chem. Phys. 109, 2279 (1998)] for standard propanal. In that paper the potential energy surface for the simultaneous methyl and asymmetric aldehydic torsions was calculated at RHF/MP2 level using the 6-311(3df,p) basis set for propanal. The fit of the energy values to symmetry-adapted functional forms was carried out by using the 28 energy values which retain the C3 dynamical symmetry of the methyl group in the optimization procedure. With this potential, as well as with the kinetic parameters and the electric dipole moment variations, the FIR frequencies and intensities for the methyl and aldehyde torsions of seven symmetric isotopomers of propanal were determined theoretically using two-dimensional calculations. The calculated spectra of propanal and three of its isotopomers were compared with the available experimental data. It is found that the calculations for the cis conformer satisfactorily reproduce the aldehyde and methyl torsion spectra and furnish also methyl torsionally excited progressions for the aldehyde torsion modes. The methyl torsion frequencies agree especially well whenever the methyl group is nondeuterated. The small deviations encountered for the deuterated compound are probably due to some mass effect, such as the zero-point vibrational energy correction, which is not taken into account in the present calculations. Finally, the influence of the deuteration on the intensities is discussed.

  7. Prediction of cloud condensation nuclei activity for organic compounds using functional group contribution methods

    DOE PAGES

    Petters, M. D.; Kreidenweis, S. M.; Ziemann, P. J.

    2016-01-19

    A wealth of recent laboratory and field experiments demonstrate that organic aerosol composition evolves with time in the atmosphere, leading to changes in the influence of the organic fraction to cloud condensation nuclei (CCN) spectra. There is a need for tools that can realistically represent the evolution of CCN activity to better predict indirect effects of organic aerosol on clouds and climate. This work describes a model to predict the CCN activity of organic compounds from functional group composition. Following previous methods in the literature, we test the ability of semi-empirical group contribution methods in Köhler theory to predict themore » effective hygroscopicity parameter, kappa. However, in our approach we also account for liquid–liquid phase boundaries to simulate phase-limited activation behavior. Model evaluation against a selected database of published laboratory measurements demonstrates that kappa can be predicted within a factor of 2. Simulation of homologous series is used to identify the relative effectiveness of different functional groups in increasing the CCN activity of weakly functionalized organic compounds. Hydroxyl, carboxyl, aldehyde, hydroperoxide, carbonyl, and ether moieties promote CCN activity while methylene and nitrate moieties inhibit CCN activity. The model can be incorporated into scale-bridging test beds such as the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to evaluate the evolution of kappa for a complex mix of organic compounds and to develop suitable parameterizations of CCN evolution for larger-scale models.« less

  8. Prediction of cloud condensation nuclei activity for organic compounds using functional group contribution methods

    NASA Astrophysics Data System (ADS)

    Petters, M. D.; Kreidenweis, S. M.; Ziemann, P. J.

    2016-01-01

    A wealth of recent laboratory and field experiments demonstrate that organic aerosol composition evolves with time in the atmosphere, leading to changes in the influence of the organic fraction to cloud condensation nuclei (CCN) spectra. There is a need for tools that can realistically represent the evolution of CCN activity to better predict indirect effects of organic aerosol on clouds and climate. This work describes a model to predict the CCN activity of organic compounds from functional group composition. Following previous methods in the literature, we test the ability of semi-empirical group contribution methods in Köhler theory to predict the effective hygroscopicity parameter, kappa. However, in our approach we also account for liquid-liquid phase boundaries to simulate phase-limited activation behavior. Model evaluation against a selected database of published laboratory measurements demonstrates that kappa can be predicted within a factor of 2. Simulation of homologous series is used to identify the relative effectiveness of different functional groups in increasing the CCN activity of weakly functionalized organic compounds. Hydroxyl, carboxyl, aldehyde, hydroperoxide, carbonyl, and ether moieties promote CCN activity while methylene and nitrate moieties inhibit CCN activity. The model can be incorporated into scale-bridging test beds such as the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to evaluate the evolution of kappa for a complex mix of organic compounds and to develop suitable parameterizations of CCN evolution for larger-scale models.

  9. ATR-FTIR characterization of organic functional groups and inorganic ions in ambient aerosols at a rural site

    NASA Astrophysics Data System (ADS)

    Coury, Charity; Dillner, Ann M.

    An Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopic method was used to measure organic functional groups and inorganic ions at Tonto National Monument (TNM), an Interagency Monitoring of Protected Visual Environments (IMPROVE) sampling site in a rural area near Phoenix, Arizona. Functional groups and ions from common aerosol compound classes such as aliphatic and aromatic CH, methylene, methyl, aldehydes/ketones, carboxylic acids, ammonium sulfate and nitrate as well as functional groups from difficult to measure compound classes such as esters/lactones, acid anhydrides, carbohydrate hydroxyl and ethers, amino acids, and amines were quantified. On average, ˜33% of the PM 1.0 mass was composed of organic aerosol. The average (standard deviation) composition of the organic aerosol at TNM was 34% (6%) biogenic functional groups, 21% (5%) oxygenated functional groups, 28% (7%) aliphatic hydrocarbon functional groups (aliphatic CH, methylene and methyl) and 17% (1%) aromatic hydrocarbon functional groups. Compositional analysis, functional group correlations, and back trajectories were used to identify three types of events with source signatures: primary biogenic-influenced, urban-influenced, and regional background. The biogenic-influenced event had high concentrations of amino acids and carbohydrate hydroxyl and ether, as well as aliphatic CH and aromatic CH functional groups and qualitatively high levels of silicate. The urban-influenced events had back trajectories traveling directly from the Phoenix area and high concentrations of hydrocarbons, oxygenated functional groups, and inorganic ions. This aerosol characterization suggests that both primary emissions in Phoenix and secondary formation of aerosols from Phoenix emissions had a major impact on the aerosol composition and concentration at TNM. The regional background source had low concentrations of all functional groups, but had higher concentrations of biogenic functional

  10. Mechanism of the addition of nonenolizable aldehydes and ketones to (Di)metallenes (R(2)X=YR(2), X = Si, Ge Y = C, Si, Ge): a density functional and multiconfigurational perturbation theory study.

    PubMed

    Mosey, Nicholas J; Baines, Kim M; Woo, Tom K

    2002-11-06

    The mechanism of the addition of nonenolizable aldehydes and ketones to group 14 (di)metallenes has been examined through a theoretical study of the addition of formaldehyde to Si=C, Ge=C, Si=Si, Si=Ge, and Ge=Ge bonds at the B3LYP/6-311++G(d,p) and CAS-MCQDPT2/6-31++G(d,p) levels of theory. The reaction pathways located can be grouped as either involving the formation of singlet diradical or zwitterionic intermediates or as concerted processes. Within each group of reaction pathways, several different mechanisms have been located, with not all mechanisms being available to all of the (di)metallenes. It was found that for reactions in which a Si-O bond results (i.e., addition to Si=C, Si=Si, and Si=Ge) both diradical and zwitterionic intermediates are possible; however, the formation of diradical intermediates was not found for reactions that result in the formation of a Ge-O bond (addition to Ge=C and Ge=Ge). The underlying cause of this pathway selectivity is examined, as well as the effect of solvent on the relative energies of the pathways. The results of the study shed light on the cause of experimentally obtained results regarding the mechanism of the reaction of (di)metallenes with nonenolizable ketones and aldehydes.

  11. Hydrazide and hydrazine reagents as reactive matrices for MALDI-MS to detect gaseous aldehydes.

    PubMed

    Shigeri, Yasushi; Ikeda, Shinya; Yasuda, Akikazu; Ando, Masanori; Sato, Hiroaki; Kinumi, Tomoya

    2014-08-01

    The reagents 19 hydrazide and 14 hydrazine were examined to function as reactive matrices for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to detect gaseous aldehydes. Among them, two hydrazide (2-hydroxybenzohydrazide and 3-hydroxy-2-naphthoic acid hydrazide) and two hydrazine reagents [2-hydrazinoquinoline and 2,4-dinitrophenylhydrazine (DNPH)] were found to react efficiently with carbonyl groups of gaseous aldehydes (formaldehyde, acetaldehyde and propionaldehyde); these are the main factors for sick building syndrome and operate as reactive matrices for MALDI-MS. Results from accurate mass measurements by JMS-S3000 Spiral-TOF suggested that protonated ion peaks corresponding to [M + H](+) from the resulting derivatives were observed in all cases with the gaseous aldehydes in an incubation, time-dependent manner. The two hydrazide and two hydrazine reagents all possessed absorbances at 337 nm (wavelength of MALDI nitrogen laser), with, significant electrical conductivity of the matrix crystal and functional groups, such as hydroxy group and amino group, being important for desorption/ionization efficiency in MALDI-MS. To our knowledge, this is the first report that gaseous molecules could be derivatized and detected directly in a single step by MALDI-MS using novel reactive matrices that were derivatizing agents with the ability to enhance desorption/ionization efficiency.

  12. Aldehyde dehydrogenase (ALDH) superfamily in plants: gene nomenclature and comparative genomics

    PubMed Central

    Brocker, Chad; Vasiliou, Melpomene; Carpenter, Sarah; Carpenter, Christopher; Zhang, Yucheng; Wang, Xiping; Kotchoni, Simeon O.; Wood, Andrew J.; Kirch, Hans-Hubert; Kopečný, David; Nebert, Daniel W.

    2012-01-01

    In recent years, there has been a significant increase in the number of completely sequenced plant genomes. The comparison of fully sequenced genomes allows for identification of new gene family members, as well as comprehensive analysis of gene family evolution. The aldehyde dehydrogenase (ALDH) gene superfamily comprises a group of enzymes involved in the NAD+- or NADP+-dependent conversion of various aldehydes to their corresponding carboxylic acids. ALDH enzymes are involved in processing many aldehydes that serve as biogenic intermediates in a wide range of metabolic pathways. In addition, many of these enzymes function as ‘aldehyde scavengers’ by removing reactive aldehydes generated during the oxidative degradation of lipid membranes, also known as lipid peroxidation. Plants and animals share many ALDH families, and many genes are highly conserved between these two evolutionarily distinct groups. Conversely, both plants and animals also contain unique ALDH genes and families. Herein we carried outgenome-wide identification of ALDH genes in a number of plant species—including Arabidopsis thaliana (thale crest), Chlamydomonas reinhardtii (unicellular algae), Oryza sativa (rice), Physcomitrella patens (moss), Vitis vinifera (grapevine) and Zea mays (maize). These data were then combined with previous analysis of Populus trichocarpa (poplar tree), Selaginella moellindorffii (gemmiferous spikemoss), Sorghum bicolor (sorghum) and Volvox carteri (colonial algae) for a comprehensive evolutionary comparison of the plant ALDH superfamily. As a result, newly identified genes can be more easily analyzed and gene names can be assigned according to current nomenclature guidelines; our goal is to clarify previously confusing and conflicting names and classifications that might confound results and prevent accurate comparisons between studies. PMID:23007552

  13. Aldehyde dehydrogenase (ALDH) superfamily in plants: gene nomenclature and comparative genomics.

    PubMed

    Brocker, Chad; Vasiliou, Melpomene; Carpenter, Sarah; Carpenter, Christopher; Zhang, Yucheng; Wang, Xiping; Kotchoni, Simeon O; Wood, Andrew J; Kirch, Hans-Hubert; Kopečný, David; Nebert, Daniel W; Vasiliou, Vasilis

    2013-01-01

    In recent years, there has been a significant increase in the number of completely sequenced plant genomes. The comparison of fully sequenced genomes allows for identification of new gene family members, as well as comprehensive analysis of gene family evolution. The aldehyde dehydrogenase (ALDH) gene superfamily comprises a group of enzymes involved in the NAD(+)- or NADP(+)-dependent conversion of various aldehydes to their corresponding carboxylic acids. ALDH enzymes are involved in processing many aldehydes that serve as biogenic intermediates in a wide range of metabolic pathways. In addition, many of these enzymes function as 'aldehyde scavengers' by removing reactive aldehydes generated during the oxidative degradation of lipid membranes, also known as lipid peroxidation. Plants and animals share many ALDH families, and many genes are highly conserved between these two evolutionarily distinct groups. Conversely, both plants and animals also contain unique ALDH genes and families. Herein we carried out genome-wide identification of ALDH genes in a number of plant species-including Arabidopsis thaliana (thale crest), Chlamydomonas reinhardtii (unicellular algae), Oryza sativa (rice), Physcomitrella patens (moss), Vitis vinifera (grapevine) and Zea mays (maize). These data were then combined with previous analysis of Populus trichocarpa (poplar tree), Selaginella moellindorffii (gemmiferous spikemoss), Sorghum bicolor (sorghum) and Volvox carteri (colonial algae) for a comprehensive evolutionary comparison of the plant ALDH superfamily. As a result, newly identified genes can be more easily analyzed and gene names can be assigned according to current nomenclature guidelines; our goal is to clarify previously confusing and conflicting names and classifications that might confound results and prevent accurate comparisons between studies.

  14. Functional group diversity increases with modularity in complex food webs

    PubMed Central

    Montoya, D.; Yallop, M.L.; Memmott, J.

    2015-01-01

    Biodiversity increases the ability of ecosystems to provide multiple functions. Most studies report a positive relationship between species richness and the number of ecosystem functions. However, it is not known whether the number of functional groups is related to the structure of the underlying species interaction network. Here we present food web data from 115 salt marsh islands and show that network structure is associated with the number of functional groups present. Functional group diversity is heterogeneously distributed across spatial scales, with some islands hosting more functional groups than others. Functional groups form modules within the community so that food webs with more modular architectures have more functional group diversity. Further, in communities with different interaction types, modularity can be seen as the multifunctional equivalent of trophic complementarity. Collectively, these findings reveal spatial heterogeneity in the number of functional groups that emerges from patterns in the structure of the food web. PMID:26059871

  15. Functional group diversity increases with modularity in complex food webs.

    PubMed

    Montoya, D; Yallop, M L; Memmott, J

    2015-06-10

    Biodiversity increases the ability of ecosystems to provide multiple functions. Most studies report a positive relationship between species richness and the number of ecosystem functions. However, it is not known whether the number of functional groups is related to the structure of the underlying species interaction network. Here we present food web data from 115 salt marsh islands and show that network structure is associated with the number of functional groups present. Functional group diversity is heterogeneously distributed across spatial scales, with some islands hosting more functional groups than others. Functional groups form modules within the community so that food webs with more modular architectures have more functional group diversity. Further, in communities with different interaction types, modularity can be seen as the multifunctional equivalent of trophic complementarity. Collectively, these findings reveal spatial heterogeneity in the number of functional groups that emerges from patterns in the structure of the food web.

  16. FT-IR quantification of the carbonyl functional group in aqueous-phase secondary organic aerosol from phenols

    NASA Astrophysics Data System (ADS)

    George, Kathryn M.; Ruthenburg, Travis C.; Smith, Jeremy; Yu, Lu; Zhang, Qi; Anastasio, Cort; Dillner, Ann M.

    2015-01-01

    Recent findings suggest that secondary organic aerosols (SOA) formed from aqueous-phase reactions of some organic species, including phenols, contribute significantly to particulate mass in the atmosphere. In this study, we employ a Fourier transform infrared (FT-IR) spectroscopic technique to identify and quantify the functional group makeup of phenolic SOA. Solutions containing an oxidant (hydroxyl radical or 3,4-dimethoxybenzaldehyde) and either one phenol (phenol, guaiacol, or syringol) or a mixture of phenols mimicking softwood or hardwood emissions were illuminated to make SOA, atomized, and collected on a filter. We produced laboratory standards of relevant organic compounds in order to develop calibrations for four functional groups: carbonyls (Cdbnd O), saturated C-H, unsaturated C-H and O-H. We analyzed the SOA samples with transmission FT-IR to identify and determine the amounts of the four functional groups. The carbonyl functional group accounts for 3-12% of the SOA sample mass in single phenolic SOA samples and 9-14% of the SOA sample mass in mixture samples. No carbonyl functional groups are present in the initial reactants. Varying amounts of each of the other functional groups are observed. Comparing carbonyls measured by FT-IR (which could include aldehydes, ketones, esters, and carboxylic acids) with eight small carboxylic acids measured by ion chromatography indicates that the acids only account for an average of 20% of the total carbonyl reported by FT-IR.

  17. Controlling Functional Group Architecture in Artificial Cells

    DTIC Science & Technology

    2015-07-02

    cycloadditions to modify reactive groups within the phospholipid membrane structure and how the nature of the reactive elements, the copper catalyst ...within the phospholipid membrane structure and how the nature of the reactive elements, the copper catalyst , the azide, and the alkyne, affect the...the copper catalyst , the azide, and the alkyne, affect the location and yield of the resulting product in the phospholipid membrane. 2. Reasons why

  18. Preparation for Group Therapy: The Effects of Preparer and Modality on Group Process and Individual Functioning.

    ERIC Educational Resources Information Center

    Bowman, Vicki E.; DeLucia, Janice L.

    1993-01-01

    Examined effects of preparer (leader versus other personnel) and modality (group versus individual) on expectations about therapy, anxiety, group and individual functioning, and leader functioning in group therapy preparation program. Findings from 32 graduate students revealed that preparation can have positive effect on clients' beliefs,…

  19. Functionalization of C(sp3)–H Bonds Using a Transient Directing Group

    PubMed Central

    Zhang, Fang-Lin; Hong, Kai; Li, Tuan-Jie; Park, Hojoon; Yu, Jin-Quan

    2016-01-01

    Proximity-driven metalation has been extensively exploited to achieve reactivity and selectivity in C–H bond activation. Despite the substantial improvement in developing more efficient and practical directing groups, their stoichiometric installation and removal limit efficiency and often applicability as well. Herein, we report the development of an amino acid reagent that reversibly reacts with aldehydes and ketones in situ via imine formation to serve as a transient directing group for activation of inert C–H bonds. Arylation of a wide range of aldehydes and ketones at the β- or γ-positions proceeds in the presence of a Pd catalyst and a catalytic amount of amino acid. The feasibility of achieving enantioselective C–H activation reactions using a chiral amino acid as the transient directing group is also demonstrated. PMID:26816374

  20. Polyvinyl alcohol cross-linked with two aldehydes

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Rieker, L. L.; Hsu, L. C.; Manzo, M. A. (Inventor)

    1982-01-01

    A film forming polyvinyl alcohol resin is admixed, in aqueous solution, with a dialdehyde crosslinking agent which is capable of crosslinking the polyvinyl alcohol resin and a water soluble acid aldehyde containing a reactive aldehyde group capable of reacting with hydroxyl groups in the polyvinyl alcohol resin and an ionizable acid hydrogen atom. The dialdehyde is present in an amount sufficient to react with from 1 to 20% by weight of the theoretical amount required to react with all of the hydroxyl groups of the polyvinyl alcohol. The amount of acid aldehyde is from 1 to 50% by weight, same basis, and is sufficient to reduce the pH of the aqueous admixture to 5 or less. The admixture is then formed into a desired physical shape, such as by casting a sheet or film, and the shaped material is then heated to simultaneously dry and crosslink the article.

  1. Metal-Free Trifluoromethylation of Aromatic and Heteroaromatic Aldehydes and Ketones

    PubMed Central

    2015-01-01

    The ability to convert simple and common substrates into fluoroalkyl derivatives under mild conditions remains an important goal for medicinal and agricultural chemists. One representative example of a desirable transformation involves the conversion of aromatic and heteroaromatic ketones and aldehydes into aryl and heteroaryl β,β,β-trifluoroethylarenes and -heteroarenes. The traditional approach for this net transformation involves stoichiometric metals and/or multistep reaction sequences that consume excessive time, material, and labor resources while providing low yields of products. To complement these traditional strategies, we report a one-pot metal-free decarboxylative procedure for accessing β,β,β-trifluoroethylarenes and -heteroarenes from readily available ketones and aldehydes. This method features several benefits, including ease of operation, readily available reagents, mild reaction conditions, high functional-group compatibility, and scalability. PMID:25001876

  2. ALDEHYDE DEHYDROGENASES EXPRESSION DURING POSTNATAL DEVELOPMENT: LIVER VS. LUNG

    EPA Science Inventory

    Aldehydes are highly reactive molecules present in the environment, and can be produced during biotransformation of xenobiotics. Although the lung can be a major target for aldehyde toxicity, development of aldehyde dehydrogenases (ALDHs), which detoxify aldehydes, in lung has be...

  3. Reversible, partial inactivation of plant betaine aldehyde dehydrogenase by betaine aldehyde: mechanism and possible physiological implications.

    PubMed

    Zárate-Romero, Andrés; Murillo-Melo, Darío S; Mújica-Jiménez, Carlos; Montiel, Carmina; Muñoz-Clares, Rosario A

    2016-04-01

    In plants, the last step in the biosynthesis of the osmoprotectant glycine betaine (GB) is the NAD(+)-dependent oxidation of betaine aldehyde (BAL) catalysed by some aldehyde dehydrogenase (ALDH) 10 enzymes that exhibit betaine aldehyde dehydrogenase (BADH) activity. Given the irreversibility of the reaction, the short-term regulation of these enzymes is of great physiological relevance to avoid adverse decreases in the NAD(+):NADH ratio. In the present study, we report that the Spinacia oleracea BADH (SoBADH) is reversibly and partially inactivated by BAL in the absence of NAD(+)in a time- and concentration-dependent mode. Crystallographic evidence indicates that the non-essential Cys(450)(SoBADH numbering) forms a thiohemiacetal with BAL, totally blocking the productive binding of the aldehyde. It is of interest that, in contrast to Cys(450), the catalytic cysteine (Cys(291)) did not react with BAL in the absence of NAD(+) The trimethylammonium group of BAL binds in the same position in the inactivating or productive modes. Accordingly, BAL does not inactivate the C(450)SSoBADH mutant and the degree of inactivation of the A(441)I and A(441)C mutants corresponds to their very different abilities to bind the trimethylammonium group. Cys(450)and the neighbouring residues that participate in stabilizing the thiohemiacetal are strictly conserved in plant ALDH10 enzymes with proven or predicted BADH activity, suggesting that inactivation by BAL is their common feature. Under osmotic stress conditions, this novel partial and reversible covalent regulatory mechanism may contribute to preventing NAD(+)exhaustion, while still permitting the synthesis of high amounts of GB and avoiding the accumulation of the toxic BAL.

  4. Functional Analytic Psychotherapy for Interpersonal Process Groups: A Behavioral Application

    ERIC Educational Resources Information Center

    Hoekstra, Renee

    2008-01-01

    This paper is an adaptation of Kohlenberg and Tsai's work, Functional Analytical Psychotherapy (1991), or FAP, to group psychotherapy. This author applied a behavioral rationale for interpersonal process groups by illustrating key points with a hypothetical client. Suggestions are also provided for starting groups, identifying goals, educating…

  5. A SeCSe-Pd(II) pincer complex as a highly efficient catalyst for allylation of aldehydes with allyltributyltin.

    PubMed

    Yao, Qingwei; Sheets, Matthew

    2006-07-07

    An air- and moisture-stable SeCSe-Pd(II) pincer complex was synthesized and found to catalyze the nucleophilic allylation of aldehydes with allyltributyltin. The allylation of a variety of aromatic and aliphatic aldehydes to give the corresponding homoallyl alcohols was performed at room temperature to 60 degrees C in yields ranging from 50% (for typical aliphatic aldehydes) to up to 97% (for aromatic aldehydes) using 5 x 10(-3) to 1 mol % of the Pd catalyst. NMR spectroscopic study indicated that a sigma-allylpalladium intermediate was formed and possibly functions as the nucleophilic species that undergoes addition to the aldehydes.

  6. Differential Item Functioning Detection across Two Methods of Defining Group Comparisons: Pairwise and Composite Group Comparisons

    ERIC Educational Resources Information Center

    Sari, Halil Ibrahim; Huggins, Anne Corinne

    2015-01-01

    This study compares two methods of defining groups for the detection of differential item functioning (DIF): (a) pairwise comparisons and (b) composite group comparisons. We aim to emphasize and empirically support the notion that the choice of pairwise versus composite group definitions in DIF is a reflection of how one defines fairness in DIF…

  7. Organocatalytic enantioselective direct additions of aldehydes to 4-vinylpyridines and electron-deficient vinylarenes and their synthetic applications.

    PubMed

    Wang, Sinan; Li, Xiangmin; Liu, Hongwei; Xu, Li; Zhuang, Jinchen; Li, Jian; Li, Hao; Wang, Wei

    2015-02-18

    We describe a synergistic catalysis strategy for the asymmetric direct addition of simple aldehydes to 4-vinylpyridines. By means of independent activation of weakly electrophilic 4-vinylpyridines by the Brønsted acid CF3SO3H (TfOH) and aldehydes by chiral diphenylprolinol tert-butyldimethylsilyl (TBDMS) ether-catalyzed formation of nucleophilic enamines in a cooperative manner, the previously unattainable highly enantioselective addition process has been realized for the first time. Notably, the power of the addition process is fueled by its high efficiency in the production of synthetically valued chiral pyridines. (1)H NMR studies of the process suggested that the nucleophilic enamine formed in situ from the chiral amine catalyst and the aldehyde is directly added to the trimeric 4-vinylpyridinium-derived species as a highly active electrophile generated from the 4-vinylpyridine in the presence of TfOH. Moreover, inspired by the similar electronic natures of pyridine and nitrobenzene, we have achieved an unprecedented chiral diphenylprolinol TBDMS ether-promoted, highly enantioselective direct addition of aldehydes to 2-nitrostyrenes without the use of TfOH as a cocatalyst. In this approach, introducing a strong electron-withdrawing group such as NO2, CF3, SO2Me, etc. on the 2-nitrostyrene creates a highly electrophilic vinyl moiety, which enables the direct addition of the in situ-formed enamine derived from the chiral amine promoter and the aldehyde. This method significantly expands the scope of the enantioselective addition process. While the electron-withdrawing nitro group is essential for activation of the vinyl group, we have demonstrated that it can be readily transformed to diverse functionalities. Furthermore, as shown, a chiral pyridine adduct serves as a key building block in the synthesis of the potent fibrinogen receptor antagonist L-734,217.

  8. [3 + 2] Cycloaddition Reaction of in Situ Formed Azaoxyallyl Cations with Aldehydes: An Approach to Oxazolidin-4-ones.

    PubMed

    Zhang, Kaifan; Yang, Chi; Yao, Hequan; Lin, Aijun

    2016-09-16

    A novel [3 + 2] cycloaddition reaction between in situ formed azaoxyallyl cations and aldehydes has been developed. This concise method allows the rapid formation of a number of oxazolidin-4-ones in high yields with good functional group tolerance at room temperature. Further transformation and late-stage modifications of drug molecules could also be achieved in good yields, highlighting the potential utility of the reaction.

  9. [Pollution Characteristics of Aldehydes and Ketones Compounds in the Exhaust of Beijing Typical Restaurants].

    PubMed

    Cheng, Jing-chen; Cui, Tong; He, Wan-qing; Nie, Lei; Wang, Jun-ling; Pan, Tao

    2015-08-01

    Aldehydes and ketones compounds, as one of the components in the exhaust of restaurants, are a class of volatile organic compounds (VOCs) with strong chemical reactivity. However, there is no systematic study on aldehydes and ketones compounds in the exhaust of restaurants. To further clarify the food source emission levels of aldehydes and ketones compounds and controlling measures, to access city group catering VOCs emissions control decision-making basis, this study selected 8 Beijing restaurants with different types. The aldehydes and ketones compounds were sampled using DNPH-silica tube, and then ultra performance liquid chromatography was used for quantitative measurement. The aldehydes and ketones concentrations of reference volume condition from 8 restaurants in descending order were Roasted Duck restaurant, Chinese Style Barbecue, Home Dishes, Western Fast-food, School Canteen, Chinese Style Fast-food, Sichuan Cuisine, Huaiyang Cuisine. The results showed that the range of aldehydes and ketones compounds (C1-C9) concentrations of reference volume condition in the exhaust of restaurants was 115.47-1035.99 microg x m(-3). The composition of aldehydes and ketones compounds in the exhaust of sampled restaurants was obviously different. The percentages of C1-C3 were above 40% in the exhaust from Chinese style restaurants. Fast food might emit more C4-C9 aldehydes and ketones compounds. From the current situation of existing aldehydes and ketones compounds control, the removal efficiency of high voltage electrostatic purifiers widely used in Beijing is limited.

  10. Thermogelling Bioadhesive Scaffolds for Intervertebral Disc Tissue Engineering: Preliminary In Vitro Comparison of Aldehyde-Based Versus Alginate Microparticle-Mediated Adhesion

    PubMed Central

    Wiltsey, C.; Christiani, T.; Williams, J.; Scaramazza, J.; Van Sciver, C.; Toomer, K.; Sheehan, J.; Branda, A.; Nitzl, A.; England, E.; Kadlowec, J.; Iftode, C.; Vernengo, J.

    2015-01-01

    Tissue engineering of certain load-bearing parts of the body can be dependent on scaffold adhesion or integration with the surrounding tissue to prevent dislocation. One such area is the regeneration of the intervertebral disc (IVD). In this work, poly(N-isopropylacrylamide) (PNIPAAm) was grafted with chondroitin sulfate (CS) (PNIPAAm-g-CS) and blended with aldehyde-modified CS to generate an injectable polymer that can form covalent bonds with tissue upon contact. However, the presence of the reactive aldehyde groups can compromise the viability of encapsulated cells. Thus, liposomes were encapsulated in the blend, designed to deliver the ECM derivative, gelatin, after the polymer has adhered to tissue and reached physiological temperature. This work is based on the hypothesis that the discharge of gelatin will enhance the biocompatibility of the material by covalently reacting with, or “end-capping”, the aldehyde functionalities within the gel that did not participate in bonding with tissue upon contact. As a comparison, formulations were also created without CS aldehyde and with an alternative adhesion mediator, mucoadhesive calcium alginate particles. Gels formed from blends of PNIPAAm-g-CS and CS aldehyde exhibited increased adhesive strength compared to PNIPAAm-g-CS alone (p<0.05). However, the addition of gelatin-loaded liposomes to the blend significantly decreased the adhesive strength (p<0.05). The encapsulation of alginate microparticles within PNIPAAm-g-CS gels caused the tensile strength to increase two-fold over that of PNIPAAm-g-CS blends with CS aldehyde (p<0.05). Cytocompatibility studies indicate that formulations containing alginate particles exhibit reduced cytotoxicity over those containing CS aldehyde. Overall, the results indicated that the adhesives composed of alginate microparticles encapsulated in PNIPAAm-g-CS have the potential to serve as a scaffold for IVD regeneration. PMID:25641647

  11. Thermogelling bioadhesive scaffolds for intervertebral disk tissue engineering: preliminary in vitro comparison of aldehyde-based versus alginate microparticle-mediated adhesion.

    PubMed

    Wiltsey, C; Christiani, T; Williams, J; Scaramazza, J; Van Sciver, C; Toomer, K; Sheehan, J; Branda, A; Nitzl, A; England, E; Kadlowec, J; Iftode, C; Vernengo, J

    2015-04-01

    Tissue engineering of certain load-bearing parts of the body can be dependent on scaffold adhesion or integration with the surrounding tissue to prevent dislocation. One such area is the regeneration of the intervertebral disc (IVD). In this work, poly(N-isopropylacrylamide) (PNIPAAm) was grafted with chondroitin sulfate (CS) (PNIPAAm-g-CS) and blended with aldehyde-modified CS to generate an injectable polymer that can form covalent bonds with tissue upon contact. However, the presence of the reactive aldehyde groups can compromise the viability of encapsulated cells. Thus, liposomes were encapsulated in the blend, designed to deliver the ECM derivative, gelatin, after the polymer has adhered to tissue and reached physiological temperature. This work is based on the hypothesis that the discharge of gelatin will enhance the biocompatibility of the material by covalently reacting with, or "end-capping", the aldehyde functionalities within the gel that did not participate in bonding with tissue upon contact. As a comparison, formulations were also created without CS aldehyde and with an alternative adhesion mediator, mucoadhesive calcium alginate particles. Gels formed from blends of PNIPAAm-g-CS and CS aldehyde exhibited increased adhesive strength compared to PNIPAAm-g-CS alone (p<0.05). However, the addition of gelatin-loaded liposomes to the blend significantly decreased the adhesive strength (p<0.05). The encapsulation of alginate microparticles within PNIPAAm-g-CS gels caused the tensile strength to increase twofold over that of PNIPAAm-g-CS blends with CS aldehyde (p<0.05). Cytocompatibility studies indicate that formulations containing alginate particles exhibit reduced cytotoxicity over those containing CS aldehyde. Overall, the results indicated that the adhesives composed of alginate microparticles encapsulated in PNIPAAm-g-CS have the potential to serve as a scaffold for IVD regeneration.

  12. Synthesis of biotinylated aldehyde polymers for biomolecule conjugation.

    PubMed

    Alconcel, Steevens N S; Kim, Sung Hye; Tao, Lei; Maynard, Heather D

    2013-06-25

    Biotinylated polymers with side-chain aldehydes were prepared for use as multifunctional scaffolds. Two different biotin-containing chain transfer agents (CTAs) and an aldehyde-containing monomer, 6-oxohexyl acrylate (6OHA), are synthesized. Poly(ethylene glycol) methyl ether acrylate (PEGA) and 6OHA are copolymerized by reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of the biotinylated CTAs. The resulting polymers are analyzed by GPC and(1) H NMR spectroscopy. The polymer end groups contained a disulfide bond, which could be readily reduced in solution to remove the biotin. Reactivity of the aldehyde side chains is demonstrated by oxime and hydrazone formation at the polymer side chains, and conjugate formation of fluorescently labeled polymers with streptavidin is investigated by gel electrophoresis.

  13. Reaction of benzoxasilocines with aromatic aldehydes: Synthesis of homopterocarpans

    PubMed Central

    Álvarez-Corral, Míriam; López-Sánchez, Cristóbal; Jiménez-González, Leticia; Rosales, Antonio; Muñoz-Dorado, Manuel; Rodríguez-García, Ignacio

    2007-01-01

    Condensation of 2H-benzo[g][1,2]oxasilocines with aromatic aldehydes in the presence of boron trifluoride affords mixtures of cis/trans 2-phenyl-3-vinylchromans with moderate yields. These can be transformed into homopterocarpans, a synthetic group of substances homologous to the natural isoflavonoid pterocarpans. PMID:17288601

  14. Direct β-Alkylation of Aldehydes via Photoredox Organocatalysis

    PubMed Central

    2015-01-01

    Direct β-alkylation of saturated aldehydes has been accomplished by synergistically combining photoredox catalysis and organocatalysis. Photon-induced enamine oxidation provides an activated β-enaminyl radical intermediate, which readily combines with a wide range of Michael acceptors to produce β-alkyl aldehydes in a highly efficient manner. Furthermore, this redox-neutral, atom-economical C–H functionalization protocol can be achieved both inter- and intramolecularly. Mechanistic studies by various spectroscopic methods suggest that a reductive quenching pathway is operable. PMID:24754456

  15. Relationships within the aldehyde dehydrogenase extended family.

    PubMed Central

    Perozich, J.; Nicholas, H.; Wang, B. C.; Lindahl, R.; Hempel, J.

    1999-01-01

    One hundred-forty-five full-length aldehyde dehydrogenase-related sequences were aligned to determine relationships within the aldehyde dehydrogenase (ALDH) extended family. The alignment reveals only four invariant residues: two glycines, a phenylalanine involved in NAD binding, and a glutamic acid that coordinates the nicotinamide ribose in certain E-NAD binary complex crystal structures, but which may also serve as a general base for the catalytic reaction. The cysteine that provides the catalytic thiol and its closest neighbor in space, an asparagine residue, are conserved in all ALDHs with demonstrated dehydrogenase activity. Sixteen residues are conserved in at least 95% of the sequences; 12 of these cluster into seven sequence motifs conserved in almost all ALDHs. These motifs cluster around the active site of the enzyme. Phylogenetic analysis of these ALDHs indicates at least 13 ALDH families, most of which have previously been identified but not grouped separately by alignment. ALDHs cluster into two main trunks of the phylogenetic tree. The largest, the "Class 3" trunk, contains mostly substrate-specific ALDH families, as well as the class 3 ALDH family itself. The other trunk, the "Class 1/2" trunk, contains mostly variable substrate ALDH families, including the class 1 and 2 ALDH families. Divergence of the substrate-specific ALDHs occurred earlier than the division between ALDHs with broad substrate specificities. A site on the World Wide Web has also been devoted to this alignment project. PMID:10210192

  16. Functional Grouping in Residential Homes for People with Intellectual Disabilities.

    ERIC Educational Resources Information Center

    Mansell, Jim; Beadle-Brown, Julie; Macdonald, Susan; Ashman, Bev

    2003-01-01

    The effects of functional grouping of 303 people with intellectual disabilities on care practices in English group homes were investigated. Residents who were non-ambulant were rated as receiving care with less interpersonal warmth and residents with severe challenging behavior were rated as receiving care with less interpersonal warmth and…

  17. Functional group-selective adsorption using scanning tunneling microscopy.

    PubMed

    Min, Young Hwan; Park, Eun Hee; Kim, Do Hwan; Kim, Sehun

    2012-04-24

    In this study, we selectively enhanced two types of adsorption of 3-mercaptoisobutyric acid on a Ge(100) surface by using the tunneling electrons from an STM and the catalytic effect of an STM tip. 3-Mercaptoisobutyric acid has two functional groups: a carboxylic acid group at one end of the molecule and a thiol group at the other end. It was found that the adsorption occurring through the carboxylic acid group was selectively enhanced by the application of electrons tunneling between an STM tip and the surface. Using this enhancement, it was possible to make thiol group-terminated surfaces at any desired location. In addition, via the use of a tungsten STM tip coated with a tungsten oxide (WO(3)) layer, we selectively catalyzed the adsorption through the thiol group. Using this catalysis, it was possible to generate carboxylic acid group-terminated surfaces at any desired location. This functional group-selective adsorption using STM could be applied in positive lithographic methods to produce semiconductor substrates terminated by desired functional groups.

  18. Multipole model for the electron group functions method.

    PubMed

    Tchougréeff, A L; Tokmachev, A M; Dronskowski, R

    2009-10-22

    Electron groups provide a natural way to introduce local concepts into quantum chemistry, and the wave functions based on the group products can be considered as a framework for constructing efficient computational methods in terms of "observable" parts of molecular systems. The elements of the group wave functions (electronic structure variables) can be optimized by requiring the number of operations proportional to the size of the molecule. This directly leads to computational methods linearly scaling for large molecular systems. In the present work we consider a particular case of such a wave function implemented for the semiempirical NDDO Hamiltonian. The electron groups are expressed in terms of optimized atomic (hybrid) orbitals with chemical bonds described by geminals and the delocalized groups described by Slater determinants (with or without spin restriction). This scheme is very fast by itself but its speed is considerably limited by the computations of the interatomic Coulomb interactions. Here we develop a consistent method based on group functions which uses the multipole scheme for interatomic interactions. The explicit usage of the atomic multipoles makes the method extremely fast, although the numerical efficiency is largely achieved due to the local character of the electron groups involved. We discuss numerical characteristics of the new method as well as its possible parametrization. We apply this method to study dodecahedral water clusters with hydrogen fluoride substitution and base the analysis on the exhaustive calculation of all symmetry-independent hydrogen-bond networks.

  19. Aldehydic load and aldehyde dehydrogenase 2 profile during the progression of post-myocardial infarction cardiomyopathy: benefits of Alda-1

    PubMed Central

    Gomes, Katia M.S.; Bechara, Luiz R.G.; Lima, Vanessa M.; Ribeiro, Márcio A.C.; Campos, Juliane C.; Dourado, Paulo M.; Kowaltowski, Alicia J.; Mochly-Rosen, Daria; Ferreira, Julio C.B.

    2015-01-01

    Background/Objectives We previously demonstrated that reducing cardiac aldehydic load by aldehyde dehydrogenase 2 (ALDH2), a mitochondrial enzyme responsible for metabolizing the major lipid peroxidation product, protects against acute ischemia/reperfusion injury and chronic heart failure. However, time-dependent changes in ALDH2 profile, aldehydic load and mitochondrial bioenergetics during progression of post-myocardial infarction (post-MI) cardiomyopathy is unknown and should be established to determine the optimal time window for drug treatment. Methods Here we characterized cardiac ALDH2 activity and expression, lipid peroxidation, 4-hydroxy-2-nonenal (4-HNE) adduct formation, glutathione pool and mitochondrial energy metabolism and H2O2 release during the 4 weeks after permanent left anterior descending (LAD) coronary artery occlusion in rats. Results We observed a sustained disruption of cardiac mitochondrial function during the progression of post-MI cardiomyopathy, characterized by >50% reduced mitochondrial respiratory control ratios and up to 2 fold increase in H2O2 release. Mitochondrial dysfunction was accompanied by accumulation of cardiac and circulating lipid peroxides and 4-HNE protein adducts and down-regulation of electron transport chain complexes I and V. Moreover, increased aldehydic load was associated with a 90% reduction in cardiac ALDH2 activity and increased glutathione pool. Further supporting an ALDH2 mechanism, sustained Alda-1 treatment (starting 24hrs after permanent LAD occlusion surgery) prevented aldehydic overload, mitochondrial dysfunction and improved ventricular function in post-MI cardiomyopathy rats. Conclusion Taken together, our findings demonstrate a disrupted mitochondrial metabolism along with an insufficient cardiac ALDH2-mediated aldehyde clearance during the progression of ventricular dysfunction, suggesting a potential therapeutic value of ALDH2 activators during the progression of post-myocardial infarction

  20. Optical behaviour of functional groups of graphene oxide

    NASA Astrophysics Data System (ADS)

    Narayanam, Pavan K.; Sankaran, K.

    2016-10-01

    Optical properties of graphene oxide (GO) dispersed in aqueous medium with aging and pH variations were investigated along with concurrent changes of oxygen functional groups of GO. Freshly prepared GO exhibit strong excitation wavelength dependent luminescence, which gets gradually nullified with aging due to the drastic reduction in fraction of polar hydroxyl groups. Fourier transform infrared studies indicated that functional groups of GO undergo spontaneous modification with aging in aqueous medium, resulting in suppression of epoxide groups and enriched adsorption of water molecules. When the pH of GO dispersed in aqueous medium was varied, unique transformations of functional groups take place causing major disruption to the sp2 hybridised carbon domains of GO. Concurrent changes in luminescence of GO infer that the broad emission from freshly prepared GO has large contribution from disorder induced localised states due to hydroxyl, epoxide, carboxyl groups and changes in relative fractions of these groups with aging and pH variations of GO dispersions strongly influence the intensity as well as emission wavelength region of GO. Especially emission features of GO are strongly influenced by the presence, fraction and transformations of epoxide and hydroxyl groups of GO.

  1. Implement the medical group revenue function. Create competitive advantage.

    PubMed

    Colucci, C

    1998-01-01

    This article shows medical groups how they can employ new financial management and information technology techniques to safeguard their revenue and income streams. These managerial techniques stem from the application of the medical group revenue function, which is defined herein. This article also describes how the medical group revenue function can be used to create value by employing a database and a decision support system. Finally, the article describes how the decision support system can be used to create competitive advantage. Through the wise use of internally generated information, medical groups can negotiate better contract terms, improve their operations, cut their costs, embark on capital investment programs and improve market share. As medical groups gain market power by improving in these areas, they will be more attractive to potential strategic allies, payers and investment bankers.

  2. Detection of rare functional variants using group ISIS.

    PubMed

    Niu, Yue S; Hao, Ning; An, Lingling

    2011-11-29

    Genome-wide association studies have been firmly established in investigations of the associations between common genetic variants and complex traits or diseases. However, a large portion of complex traits and diseases cannot be explained well by common variants. Detecting rare functional variants becomes a trend and a necessity. Because rare variants have such a small minor allele frequency (e.g., <0.05), detecting functional rare variants is challenging. Group iterative sure independence screening (ISIS), a fast group selection tool, was developed to select important genes and the single-nucleotide polymorphisms within. The performance of the group ISIS and group penalization methods is compared for detecting important genes in the Genetic Analysis Workshop 17 data. The results suggest that the group ISIS is an efficient tool to discover genes and single-nucleotide polymorphisms associated to phenotypes.

  3. Cyanobacterial aldehyde deformylase oxygenation of aldehydes yields n-1 aldehydes and alcohols in addition to alkanes.

    PubMed

    Aukema, Kelly G; Makris, Thomas M; Stoian, Sebastian A; Richman, Jack E; Münck, Eckard; Lipscomb, John D; Wackett, Lawrence P

    2013-10-04

    Aldehyde-deformylating oxygenase (ADO) catalyzes O2-dependent release of the terminal carbon of a biological substrate, octadecanal, to yield formate and heptadecane in a reaction that requires external reducing equivalents. We show here that ADO also catalyzes incorporation of an oxygen atom from O2 into the alkane product to yield alcohol and aldehyde products. Oxygenation of the alkane product is much more pronounced with C9-10 aldehyde substrates, so that use of nonanal as the substrate yields similar amounts of octane, octanal, and octanol products. When using doubly-labeled [1,2-(13)C]-octanal as the substrate, the heptane, heptanal and heptanol products each contained a single (13)C-label in the C-1 carbons atoms. The only one-carbon product identified was formate. [(18)O]-O2 incorporation studies demonstrated formation of [(18)O]-alcohol product, but rapid solvent exchange prevented similar determination for the aldehyde product. Addition of [1-(13)C]-nonanol with decanal as the substrate at the outset of the reaction resulted in formation of [1-(13)C]-nonanal. No (13)C-product was formed in the absence of decanal. ADO contains an oxygen-bridged dinuclear iron cluster. The observation of alcohol and aldehyde products derived from the initially formed alkane product suggests a reactive species similar to that formed by methane monooxygenase (MMO) and other members of the bacterial multicomponent monooxygenase family. Accordingly, characterization by EPR and Mössbauer spectroscopies shows that the electronic structure of the ADO cluster is similar, but not identical, to that of MMO hydroxylase component. In particular, the two irons of ADO reside in nearly identical environments in both the oxidized and fully reduced states, whereas those of MMOH show distinct differences. These favorable characteristics of the iron sites allow a comprehensive determination of the spin Hamiltonian parameters describing the electronic state of the diferrous cluster for the

  4. Single or functionalized fullerenes interacting with heme group

    SciTech Connect

    Costa, Wallison Chaves; Diniz, Eduardo Moraes

    2014-09-15

    The heme group is responsible for iron transportation through the bloodstream, where iron participates in redox reactions, electron transfer, gases detection etc. The efficiency of such processes can be reduced if the whole heme molecule or even the iron is somehow altered from its original oxidation state, which can be caused by interactions with nanoparticles as fullerenes. To verify how such particles alter the geometry and electronic structure of heme molecule, here we report first principles calculations based on density functional theory of heme group interacting with single C{sub 60} fullerene or with C{sub 60} functionalized with small functional groups (−CH{sub 3}, −COOH, −NH{sub 2}, −OH). The calculations shown that the system heme + nanoparticle has a different spin state in comparison with heme group if the fullerene is functionalized. Also a functional group can provide a stronger binding between nanoparticle and heme molecule or inhibit the chemical bonding in comparison with single fullerene results. In addition heme molecule loses electrons to the nanoparticles and some systems exhibited a geometry distortion in heme group, depending on the binding energy. Furthermore, one find that such nanoparticles induce a formation of spin up states in heme group. Moreover, there exist modifications in density of states near the Fermi energy. Although of such changes in heme electronic structure and geometry, the iron atom remains in the heme group with the same oxidation state, so that processes that involve the iron might not be affected, only those that depend on the whole heme molecule.

  5. Extraordinary properties of functional integrals and groups of diffeomorphisms

    NASA Astrophysics Data System (ADS)

    Belokurov, V. V.; Shavgulidze, E. T.

    2017-03-01

    A review of the work of the authors is presented, in which corollaries of the quasi-invariance of functional integrals on the Wiener measure with respect to the action of a group of diffeomorphisms are studied, and the behavior of functional integrals with nonlinear nonlocal change of variables of integration is investigated as well. Using these substitutions, the functional integrals over discontinuous paths can be determined. The simplest models of the (Euclidean) quantum field theory are offered, in which the presence of hidden internal symmetries or the allowance for discontinuous paths in functional integrals leads to a number of paradoxical properties contradicting the conventional view.

  6. Process for producing furan from furfural aldehyde

    DOEpatents

    Diebold, J.P.; Evans, R.J.

    1987-04-06

    A process of producing furan and derivatives thereof as disclosed. The process includes generating furfural aldehyde vapors and then passing those vapors over a zeolite catalyst at a temperature and for a residence time effective to decarbonylate the furfural aldehydes to form furans and derivatives thereof. The resultant furan vapors and derivatives are then separated. In a preferred form, the furfural aldehyde vapors are generated during the process of converting biomass materials to liquid and gaseous fuels.

  7. Process for producing furan from furfural aldehyde

    DOEpatents

    Diebold, James P.; Evans, Robert J.

    1988-01-01

    A process of producing furan and derivatives thereof is disclosed. The process includes generating furfural aldehyde vapors and then passing those vapors over a zeolite catalyst at a temperature and for a residence time effective to decarbonylate the furfural aldehydes to form furans and derivatives thereof. The resultant furan vapors and derivatives are then separated. In a preferred form, the furfural aldehyde vapors are generated during the process of converting biomass materials to liquid and gaseous fuels.

  8. Solving renormalization group equations with the Lambert W function

    NASA Astrophysics Data System (ADS)

    Sonoda, H.

    2013-04-01

    It has been known for some time that 2-loop renormalization group equations of a dimensionless parameter can be solved in a closed form in terms of the Lambert W function. We apply the method to a generic theory with a Gaussian fixed point to construct renormalization group invariant physical parameters such as a coupling constant and a physical squared mass. As a further application, we speculate a possible exact effective potential for the O(N) linear sigma model in four dimensions.

  9. Synthesis of bio-based aldehyde from seaweed polysaccharide and its interaction with bovine serum albumin.

    PubMed

    Kholiya, Faisal; Chaudhary, Jai Prakash; Vadodariya, Nilesh; Meena, Ramavatar

    2016-10-05

    Here, we demonstrate a successful synthesis of bio-based aldehyde namely dialdehyde-carboxymethylagarose (DCMA) using carboxymethyagarose (CMA). Further reaction parameters (i.e. reaction temperature, pH and periodate concentration) were optimized to achieve maximum aldehyde content and product yield. The synthesis of DCMA was confirmed by employing FTIR, (1)H NMR, XRD, SEM, AFM, TGA, DSC, EA and GPC techniques. To investigate the aldehyde functionality, DCMA was allowed to interact with BSA and obtained results were found to be comparable with that of synthetic aldehyde (Formaldehyde). Further interaction of DCMA with BSA was confirmed by using UV-vis, FTIR, fluorescent spectroscopy, CD and DLS analysis. Results of this study revealed that bio-based aldehyde behaves like formaldehyde. This study adds value to abundant marine biopolymers and opens the new research area for polymer researchers.

  10. Colorimetric monitoring of solid-phase aldehydes using 2,4-dinitrophenylhydrazine.

    PubMed

    Shannon, Simon K; Barany, George

    2004-01-01

    A simple and rapid method to achieve colorimetric monitoring of resin-bound aldehydes, based on ambient temperature reaction with 2,4-dinitrophenylhydrazine (DNPH) in the presence of dilute acid, has been developed as an adjunct to solid-phase organic synthesis and combinatorial chemistry. By this test, the presence of aldehydes is indicated by a red to dark-orange appearance, within a minute. Alternatively, resins that are free of aldehydes or in which aldehyde functions have reacted completely retain their original color. The DNPH test was demonstrated for poly(ethylene glycol)-polystyrene (PEG-PS), aminomethyl polystyrene (AMP), cross-linked ethoxylate acrylate resin (CLEAR), and acryloylated O,O'-bis(2-aminopropyl)poly(ethylene glycol) (PEGA) supports and gave results visible to the naked eye at levels as low as 18 micromol of aldehyde per gram of resin.

  11. Acyclovir-induced nephrotoxicity: the role of the acyclovir aldehyde metabolite.

    PubMed

    Gunness, Patrina; Aleksa, Katarina; Bend, John; Koren, Gideon

    2011-11-01

    For decades, acyclovir-induced nephrotoxicity was believed to be secondary to crystalluria. Clinical evidence of nephrotoxicity in the absence of crystalluria suggests that acyclovir induces direct insult to renal tubular cells. We postulated that acyclovir is metabolized by the alcohol dehydrogenase (ADH) enzyme to acyclovir aldehyde, which is metabolized by the aldehyde dehydrognase 2 (ALDH2) enzyme to 9-carboxymethoxymethylguanine (CMMG). We hypothesized that acyclovir aldehyde plays a role in acyclovir-induced nephrotoxicity. Human renal proximal tubular (HK-2) cells were used as our in vitro model. Western blot and enzymes activities assays were performed to determine whether the HK-2 cells express ADH and ALDH2 isozymes, respectively. Cytotoxicity (measured as a function of cell viability) assays were conducted to determine (1) whether the acyclovir aldehyde plays a role in acyclovir-induced nephrotoxicity and (2) whether CMMG induces cell death. A colorimetric assay was performed to determine whether acyclovir was metabolized to an aldehyde in vitro. Our results illustrated that (1) HK-2 cells express ADH and ALDH2 isozymes, (2) 4-methylpyrazole rendered significant protection against cell death, (3) CMMG does not induce cell death, and (4) acyclovir was metabolized to an aldehyde in tubular cells. These data indicate that acyclovir aldehyde is produced in HK-2 cells and that inhibition of its production by 4-methylpyrazole offers significant protection from cell death in vitro, suggesting that acyclovir aldehyde may cause the direct renal tubular insult associated with acyclovir.

  12. DIFFERENTIATING THE TOXICITY OF CARCINOGENIC ALDEHYDES FROM NONCARCINOGENIC ALDEHYDES IN THE RAT NOSE USING CDNA ARRAYS

    EPA Science Inventory

    Differentiating the Toxicity of Carcinogenic Aldehydes from Noncarcinogenic Aldehydes in the Rat Nose Using cDNA Arrays.

    Formaldehyde is a widely used aldehyde in many industrial settings, the tanning process, household products, and is a contaminant in cigarette smoke. H...

  13. Species, functional groups, and thresholds in ecological resilience

    USGS Publications Warehouse

    Sundstrom, Shana M.; Allen, Craig R.; Barichievy, Chris

    2012-01-01

    The cross-scale resilience model states that ecological resilience is generated in part from the distribution of functions within and across scales in a system. Resilience is a measure of a system's ability to remain organized around a particular set of mutually reinforcing processes and structures, known as a regime. We define scale as the geographic extent over which a process operates and the frequency with which a process occurs. Species can be categorized into functional groups that are a link between ecosystem processes and structures and ecological resilience. We applied the cross-scale resilience model to avian species in a grassland ecosystem. A species’ morphology is shaped in part by its interaction with ecological structure and pattern, so animal body mass reflects the spatial and temporal distribution of resources. We used the log-transformed rank-ordered body masses of breeding birds associated with grasslands to identify aggregations and discontinuities in the distribution of those body masses. We assessed cross-scale resilience on the basis of 3 metrics: overall number of functional groups, number of functional groups within an aggregation, and the redundancy of functional groups across aggregations. We assessed how the loss of threatened species would affect cross-scale resilience by removing threatened species from the data set and recalculating values of the 3 metrics. We also determined whether more function was retained than expected after the loss of threatened species by comparing observed loss with simulated random loss in a Monte Carlo process. The observed distribution of function compared with the random simulated loss of function indicated that more functionality in the observed data set was retained than expected. On the basis of our results, we believe an ecosystem with a full complement of species can sustain considerable species losses without affecting the distribution of functions within and across aggregations, although

  14. Psychosocial functioning of two groups of morbidly obese patients.

    PubMed

    Rosen, L W; Aniskiewicz, A S

    1983-01-01

    Fourteen morbidly obese women who were candidates for intestinal bypass surgery were compared in terms of psychosocial functioning and dietary behavior to 14 morbidly obese women who elected not to undergo the bypass procedure. Each patient underwent a psychiatric evaluation which included a developmental and dietary history, a mental status exam, and the administration of the MMPI. Diagnoses were based on the DSM-III multi-axial system. There was no difference between the bypass group and the non-bypass group on the Axis I diagnoses, however the bypass group did have a significantly higher frequency of Axis II diagnoses. The bypass group demonstrated significantly higher levels of psychosocial stressors (Axis IV) and lower levels of adaptive functioning (Axis V) when compared to the non-bypass group. The bypass patients also had a significantly higher frequency of past suicide attempts. On the MMPI, the bypass group had significantly higher elevations on scales 2 (depression), 4 (psychopathic deviate), 6 (paranoia), and 0 (social introversion). There were no significant differences between the groups in terms of dietary history and behavior, except that significantly fewer bypass patients could place a numerical estimate on their daily energy intake. These results were discussed in terms of their implications for the assessment and treatment of morbidly obese patients.

  15. Victimization in the Peer Group and Children's Academic Functioning

    ERIC Educational Resources Information Center

    Schwartz, David; Gorman, Andrea Hopmeyer; Nakamoto, Jonathan; Toblin, Robin L.

    2005-01-01

    This short-term longitudinal investigation focused on associations between victimization in the peer group and academic functioning over a 1-year period. The authors used a multi-informant approach to assess peer victimization, symptoms of depression, and academic outcomes for 199 elementary school children (average age of 9.0 years; 105 boys, 94…

  16. Functional grouping in residential homes for people with intellectual disabilities.

    PubMed

    Mansell, Jim; Beadle-Brown, Julie; Macdonald, Susan; Ashman, Bev

    2003-01-01

    The effects of functional grouping of people with intellectual disabilities on care practices in small residential homes in the community were investigated. A group comparison and a matched-pairs comparison were carried out in settings where less than or more than 75% residents were non-verbal, non-ambulant, had severe challenging behaviour, severe social impairment or were verbal and ambulant. Further analysis, focused on those with challenging behaviour was carried out using ordinal regression. In the group-comparison study, no significant differences were found for three of the five groups. Residents who were non-ambulant were rated as receiving care with less interpersonal warmth in grouped settings; residents with severe challenging behaviour were rated as receiving less good care practices in four respects (interpersonal warmth, assistance from staff, level of speech and staff teamwork) in grouped settings. The matched-pairs comparison found significant differences only for people with challenging behaviour, where grouped settings achieved less good results in terms of interpersonal warmth and staff teamwork. Higher adaptive behaviour and mixed settings were predictive of better care practices on 13 of 14 items of the Active Support Measure (ASM), with some setting variables also predictive for some items. Care practices only appear to vary for people with challenging behaviour, where grouped settings appear to offer less good results in some respects.

  17. Rh(III)-Catalyzed Diastereoselective C–H Bond Addition/Cyclization Cascade of Enone Tethered Aldehydes

    PubMed Central

    Boerth, Jeffrey A.

    2016-01-01

    The Rh(III)-catalyzed cascade addition of a C–H bond across alkene and carbonyl π-bonds is reported. The reaction proceeds under mild reaction conditions with low catalyst loading. A range of directing groups were shown to be effective as was the functionalization of alkenyl in addition to aromatic C(sp2)–H bonds. When the enone and aldehyde electrophile were tethered together, cyclic β-hydroxy ketones with three contiguous stereocenters were obtained with high diastereoselectivity. The intermolecular three-component cascade reaction was demonstrated for both aldehyde and imine electrophiles. Moreover, the first x-ray structure of a cationic Cp*Rh(III) enolate with interatomic distances consistent with an η3-bound enolate is reported. PMID:26918112

  18. Linking functional group richness and ecosystem functions of dung beetles: an experimental quantification.

    PubMed

    Milotić, Tanja; Quidé, Stijn; Van Loo, Thomas; Hoffmann, Maurice

    2017-01-01

    Dung beetles form an insect group that fulfils important functions in terrestrial ecosystems throughout the world. These include nutrient cycling through dung removal, soil bioturbation, plant growth, secondary seed dispersal and parasite control. We conducted field experiments at two sites in the northern hemisphere temperate region in which dung removal and secondary seed dispersal were assessed. Dung beetles were classified in three functional groups, depending on their size and dung manipulation method: dwellers, large and small tunnelers. Other soil inhabiting fauna were included as a fourth functional group. Dung removal and seed dispersal by each individual functional group and combinations thereof were estimated in exclusion experiments using different dung types. Dwellers were the most diverse and abundant group, but tunnelers were dominant in terms of biomass. All dung beetle functional groups had a clear preference for fresh dung. The ecosystem services in dung removal and secondary seed dispersal provided by dung beetles were significant and differed between functional groups. Although in absolute numbers more dwellers were found, large tunnelers were disproportionally important for dung burial and seed removal. In the absence of dung beetles, other soil inhabiting fauna, such as earthworms, partly took over the dung decomposing role of dung beetles while most dung was processed when all native functional groups were present. Our results, therefore, emphasize the need to conserve functionally complete dung ecosystems to maintain full ecosystem functioning.

  19. On the role of microsomal aldehyde dehydrogenase in metabolism of aldehydic products of lipid peroxidation.

    PubMed

    Antonenkov, V D; Pirozhkov, S V; Panchenko, L F

    1987-11-30

    To elucidate a possible role of membrane-bound aldehyde dehydrogenase in the detoxication of aldehydic products of lipid peroxidation, the substrate specificity of the highly purified microsomal enzyme was investigated. The aldehyde dehydrogenase was active with different aliphatic aldehydes including 4-hydroxyalkenals, but did not react with malonic dialdehyde. When Fe/ADP-ascorbate-induced lipid peroxidation of arachidonic acid was carried out in an in vitro system, the formation of products which react with microsomal aldehyde dehydrogenase was observed parallel with malonic dialdehyde accumulation.

  20. Aldehyde Detection in Electronic Cigarette Aerosols

    PubMed Central

    2017-01-01

    Acetaldehyde, acrolein, and formaldehyde are the principal toxic aldehydes present in cigarette smoke and contribute to the risk of cardiovascular disease and noncancerous pulmonary disease. The rapid growth of the use of electronic cigarettes (e-cigarettes) has raised concerns over emissions of these harmful aldehydes. This work determines emissions of these aldehydes in both free and bound (aldehyde–hemiacetal) forms and other carbonyls from the use of e-cigarettes. A novel silicon microreactor with a coating phase of 4-(2-aminooxyethyl)-morpholin-4-ium chloride (AMAH) was used to trap carbonyl compounds in the aerosols of e-cigarettes via oximation reactions. AMAH–aldehyde adducts were measured using gas chromatography–mass spectrometry. 1H nuclear magnetic resonance spectroscopy was used to analyze hemiacetals in the aerosols. These aldehydes were detected in the aerosols of all e-cigarettes. Newer-generation e-cigarette devices generated more aldehydes than the first-generation e-cigarettes because of higher battery power output. Formaldehyde–hemiacetal was detected in the aerosols generated from some e-liquids using the newer e-cigarette devices at a battery power output of 11.7 W and above. The emission of these aldehydes from all e-cigarettes, especially higher levels of aldehydes from the newer-generation e-cigarette devices, indicates the risk of using e-cigarettes. PMID:28393137

  1. Functional gene group analysis identifies synaptic gene groups as risk factor for schizophrenia

    PubMed Central

    Lips, E S; Cornelisse, L N; Toonen, R F; Min, J L; Hultman, C M; Holmans, P A; O'Donovan, M C; Purcell, S M; Smit, A B; Verhage, M; Sullivan, P F; Visscher, P M; Posthuma, D

    2012-01-01

    Schizophrenia is a highly heritable disorder with a polygenic pattern of inheritance and a population prevalence of ∼1%. Previous studies have implicated synaptic dysfunction in schizophrenia. We tested the accumulated association of genetic variants in expert-curated synaptic gene groups with schizophrenia in 4673 cases and 4965 healthy controls, using functional gene group analysis. Identifying groups of genes with similar cellular function rather than genes in isolation may have clinical implications for finding additional drug targets. We found that a group of 1026 synaptic genes was significantly associated with the risk of schizophrenia (P=7.6 × 10−11) and more strongly associated than 100 randomly drawn, matched control groups of genetic variants (P<0.01). Subsequent analysis of synaptic subgroups suggested that the strongest association signals are derived from three synaptic gene groups: intracellular signal transduction (P=2.0 × 10−4), excitability (P=9.0 × 10−4) and cell adhesion and trans-synaptic signaling (P=2.4 × 10−3). These results are consistent with a role of synaptic dysfunction in schizophrenia and imply that impaired intracellular signal transduction in synapses, synaptic excitability and cell adhesion and trans-synaptic signaling play a role in the pathology of schizophrenia. PMID:21931320

  2. Functional gene group analysis identifies synaptic gene groups as risk factor for schizophrenia.

    PubMed

    Lips, E S; Cornelisse, L N; Toonen, R F; Min, J L; Hultman, C M; Holmans, P A; O'Donovan, M C; Purcell, S M; Smit, A B; Verhage, M; Sullivan, P F; Visscher, P M; Posthuma, D

    2012-10-01

    Schizophrenia is a highly heritable disorder with a polygenic pattern of inheritance and a population prevalence of ~1%. Previous studies have implicated synaptic dysfunction in schizophrenia. We tested the accumulated association of genetic variants in expert-curated synaptic gene groups with schizophrenia in 4673 cases and 4965 healthy controls, using functional gene group analysis. Identifying groups of genes with similar cellular function rather than genes in isolation may have clinical implications for finding additional drug targets. We found that a group of 1026 synaptic genes was significantly associated with the risk of schizophrenia (P=7.6 × 10(-11)) and more strongly associated than 100 randomly drawn, matched control groups of genetic variants (P<0.01). Subsequent analysis of synaptic subgroups suggested that the strongest association signals are derived from three synaptic gene groups: intracellular signal transduction (P=2.0 × 10(-4)), excitability (P=9.0 × 10(-4)) and cell adhesion and trans-synaptic signaling (P=2.4 × 10(-3)). These results are consistent with a role of synaptic dysfunction in schizophrenia and imply that impaired intracellular signal transduction in synapses, synaptic excitability and cell adhesion and trans-synaptic signaling play a role in the pathology of schizophrenia.

  3. Interaction of aldehydes derived from lipid peroxidation and membrane proteins

    PubMed Central

    Pizzimenti, Stefania; Ciamporcero, Eric; Daga, Martina; Pettazzoni, Piergiorgio; Arcaro, Alessia; Cetrangolo, Gianpaolo; Minelli, Rosalba; Dianzani, Chiara; Lepore, Alessio; Gentile, Fabrizio; Barrera, Giuseppina

    2013-01-01

    A great variety of compounds are formed during lipid peroxidation of polyunsaturated fatty acids of membrane phospholipids. Among them, bioactive aldehydes, such as 4-hydroxyalkenals, malondialdehyde (MDA) and acrolein, have received particular attention since they have been considered as toxic messengers that can propagate and amplify oxidative injury. In the 4-hydroxyalkenal class, 4-hydroxy-2-nonenal (HNE) is the most intensively studied aldehyde, in relation not only to its toxic function, but also to its physiological role. Indeed, HNE can be found at low concentrations in human tissues and plasma and participates in the control of biological processes, such as signal transduction, cell proliferation, and differentiation. Moreover, at low doses, HNE exerts an anti-cancer effect, by inhibiting cell proliferation, angiogenesis, cell adhesion and by inducing differentiation and/or apoptosis in various tumor cell lines. It is very likely that a substantial fraction of the effects observed in cellular responses, induced by HNE and related aldehydes, be mediated by their interaction with proteins, resulting in the formation of covalent adducts or in the modulation of their expression and/or activity. In this review we focus on membrane proteins affected by lipid peroxidation-derived aldehydes, under physiological and pathological conditions. PMID:24027536

  4. [Identification of the functional groups of yeast thiamine pyrophosphokinase].

    PubMed

    Voskoboev, A I; Grinevich, V P

    1978-10-01

    The content of free sulfhydril groups in yeast thiamine pyrophosphokinase (EC 2.7.6.2) was studied. Their blocking was found not to affect considerably the enzyme activity. N-bromsuccinimide developes the inhibitory effect only if taken in excessive concentrations, which indicates that tryptophane has no key position for the enzyme-substrate complex formation. On account of high speed of photoinactivation with Rose bengale and methilene blue, sigmoid dependence of activity loss on pH under irradiation, characteristic narrowing of the modified enzyme absorption spectrum, it is suggested that imidazole residue of the histidine is one of the functional groups of thiamine pyrophosphokinase.

  5. Oxygen functional groups in graphitic carbon nitride for enhanced photocatalysis.

    PubMed

    Liu, Shizhen; Li, Degang; Sun, Hongqi; Ang, Ha Ming; Tadé, Moses O; Wang, Shaobin

    2016-04-15

    Metal-free semiconductors offer a new opportunity for environmental photocatalysis toward a potential breakthrough in high photo efficiency with complete prevention of metal leaching. In this study, graphitic carbon nitride (GCN) modified by oxygen functional groups was synthesized by a hydrothermal treatment of pristine GCN at different temperatures with H2O2. Insights into the emerging characteristics of the modified GCN in photocatalysis were obtained by determining the optical properties, band structure, electrochemical activity and pollutant degradation efficiency. It was found that the introduction of GCN with oxygen functional groups can enhance light absorption and accelerate electron transfer so as to improve the photocatalytic reaction efficiency. The photoinduced reactive radicals and the associated photodegradation were investigated by in situ electron paramagnetic resonance (EPR). The reactive radicals, O2(-) and OH, were responsible for organic degradation.

  6. Functional group dependent dissociative electron attachment to simple organic molecules

    NASA Astrophysics Data System (ADS)

    Prabhudesai, Vaibhav S.; Nandi, Dhananjay; Kelkar, Aditya H.; Krishnakumar, E.

    2008-04-01

    Dissociative electron attachment (DEA) cross sections for simple organic molecules, namely, acetic acid, propanoic acid, methanol, ethanol, and n-propyl amine are measured in a crossed beam experiment. We find that the H- ion formation is the dominant channel of DEA for these molecules and takes place at relatively higher energies (>4eV) through the core excited resonances. Comparison of the cross sections of the H- channel from these molecules with those from NH3, H2O, and CH4 shows the presence of functional group dependence in the DEA process. We analyze this new phenomenon in the context of the results reported on other organic molecules. This discovery of functional group dependence has important implications such as control in electron induced chemistry and understanding radiation induced damage in biological systems.

  7. An Efficient Synthesis of 2-Substituted Benzimidazoles via Photocatalytic Condensation of o-Phenylenediamines and Aldehydes.

    PubMed

    Kovvuri, Jeshma; Nagaraju, Burri; Kamal, Ahmed; Srivastava, Ajay K

    2016-10-10

    A photocatalytic method has been developed for the efficient synthesis of functionalized benzimidazoles. This protocol involves photocatalytic condensation of o-phenylenediamines with various aldehydes using the Rose Bengal as photocatalyst. The method was found to be general and was successfully employed for accessing pharmaceutically important benzimidazoles by the condensation of aromatic, heteroaromatic and aliphatic aldehydes with o-phenylenediamines, in good-to-excellent yields. Notably, the method was found to be effective for the condensation of less reactive heterocyclic aldehydes with o-phenylenediamines.

  8. Keldysh functional renormalization group for electronic properties of graphene

    NASA Astrophysics Data System (ADS)

    Fräßdorf, Christian; Mosig, Johannes E. M.

    2017-03-01

    We construct a nonperturbative nonequilibrium theory for graphene electrons interacting via the instantaneous Coulomb interaction by combining the functional renormalization group method with the nonequilibrium Keldysh formalism. The Coulomb interaction is partially bosonized in the forward scattering channel resulting in a coupled Fermi-Bose theory. Quantum kinetic equations for the Dirac fermions and the Hubbard-Stratonovich boson are derived in Keldysh basis, together with the exact flow equation for the effective action and the hierarchy of one-particle irreducible vertex functions, taking into account a possible nonzero expectation value of the bosonic field. Eventually, the system of equations is solved approximately under thermal equilibrium conditions at finite temperature, providing results for the renormalized Fermi velocity and the static dielectric function, which extends the zero-temperature results of Bauer et al., Phys. Rev. B 92, 121409 (2015), 10.1103/PhysRevB.92.121409.

  9. Functional renormalization group for the U (1 )-T56 tensorial group field theory with closure constraint

    NASA Astrophysics Data System (ADS)

    Lahoche, Vincent; Ousmane Samary, Dine

    2017-02-01

    This paper is focused on the functional renormalization group applied to the T56 tensor model on the Abelian group U (1 ) with closure constraint. For the first time, we derive the flow equations for the couplings and mass parameters in a suitable truncation around the marginal interactions with respect to the perturbative power counting. For the second time, we study the behavior around the Gaussian fixed point, and show that the theory is nonasymptotically free. Finally, we discuss the UV completion of the theory. We show the existence of several nontrivial fixed points, study the behavior of the renormalization group flow around them, and point out evidence in favor of an asymptotically safe theory.

  10. Toward aldehyde and alkane production by removing aldehyde reductase activity in Escherichia coli.

    PubMed

    Rodriguez, Gabriel M; Atsumi, Shota

    2014-09-01

    Advances in synthetic biology and metabolic engineering have enabled the construction of novel biological routes to valuable chemicals using suitable microbial hosts. Aldehydes serve as chemical feedstocks in the synthesis of rubbers, plastics, and other larger molecules. Microbial production of alkanes is dependent on the formation of a fatty aldehyde intermediate which is converted to an alkane by an aldehyde deformylating oxygenase (ADO). However, microbial hosts such as Escherichia coli are plagued by many highly active endogenous aldehyde reductases (ALRs) that convert aldehydes to alcohols, which greatly complicates strain engineering for aldehyde and alkane production. It has been shown that the endogenous ALR activity outcompetes the ADO enzyme for fatty aldehyde substrate. The large degree of ALR redundancy coupled with an incomplete database of ALRs represents a significant obstacle in engineering E. coli for either aldehyde or alkane production. In this study, we identified 44 ALR candidates encoded in the E. coli genome using bioinformatics tools, and undertook a comprehensive screening by measuring the ability of these enzymes to produce isobutanol. From the pool of 44 candidates, we found five new ALRs using this screening method (YahK, DkgA, GldA, YbbO, and YghA). Combined deletions of all 13 known ALRs resulted in a 90-99% reduction in endogenous ALR activity for a wide range of aldehyde substrates (C2-C12). Elucidation of the ALRs found in E. coli could guide one in reducing competing alcohol formation during alkane or aldehyde production.

  11. Characterization of Sea Lettuce Surface Functional Groups by Potentiometric Titrations

    NASA Astrophysics Data System (ADS)

    Ebling, A. M.; Schijf, J.

    2008-12-01

    In pursuit of our ultimate goal to better understand the prodigious capacity of the marine macroalga Ulva lactuca (sea lettuce) for adsorbing a broad range of dissolved trace metals from seawater, we performed an initial characterization of its surface functional groups. Specifically, the number of distinct functional groups as well as their individual bulk concentrations and acid dissociation constants (pKas) were determined by potentiometric titrations in NaCl solutions of various ionic strengths (I = 0.01-5.0 M), under inert nitrogen atmosphere at 25°C. Depending on the ionic strength, Ulva samples were manually titrated down to pH 2 or 3 with 1 N HCl and then up to pH 10 with 1 N NaOH in steps of 0.1-0.2 units, continuously monitoring pH with a glass combination electrode. Titrations of a dehydrated Ulva standard reference material (BCR-279) were compared with fresh Ulva tissue cultured in our laboratory. A titration in filtered natural seawater was also compared with one in an NaCl solution of equal ionic strength. Equilibrium constants for the ionization of water in NaCl solutions as a function of ionic strength were obtained from the literature. Fits to the titration data ([H]T vs. pH) were performed with the FITEQL4.0 computer code using non-electrostatic 3-, 4-, and 5-site models, either by fixing ionic strength at its experimental value or by allowing it to be extrapolated to zero, while considering all functional group pKas and bulk concentrations as adjustable parameters. Since pKas and bulk concentrations were found to be strongly correlated, the latter were also fixed in some cases to further constrain the pKas. Whereas these calculations are currently ongoing, preliminary results point to three, possibly four, functional groups with pKas of about 4.1, 6.3, and 9.5 at I = 0. Bulk concentrations of the three groups are very similar, about 5-6×10-4 mol/g based on dry weight, which suggests that all are homogeneously distributed over the surface and

  12. Microwave-Assisted Condensation Reactions of Acetophenone Derivatives and Activated Methylene Compounds with Aldehydes Catalyzed by Boric Acid under Solvent-Free Conditions.

    PubMed

    Brun, Elodie; Safer, Abdelmounaim; Carreaux, François; Bourahla, Khadidja; L'helgoua'ch, Jean-Martial; Bazureau, Jean-Pierre; Villalgordo, Jose Manuel

    2015-06-23

    We here disclosed a new protocol for the condensation of acetophenone derivatives and active methylene compounds with aldehydes in the presence of boric acid under microwave conditions. Implementation of the reaction is simple, healthy and environmentally friendly owing to the use of a non-toxic catalyst coupled to a solvent-free procedure. A large variety of known or novel compounds have thus been prepared, including with substrates bearing acid or base-sensitive functional groups.

  13. Substrate-Directed Hydroacylation: Rh-Catalyzed Coupling of Vinyl Phenols and Non-Chelating Aldehydes

    PubMed Central

    Murphy, Stephen K.; Bruch, Achim

    2014-01-01

    We report a protocol for branched-selective hydroacylation of vinylphenols with aryl, alkenyl and alkyl aldehydes. This cross-coupling yields α-aryl ketones that can be cyclized to benzofurans, and it enables access to eupomatenoid natural products in four steps or less from eugenol. Excellent reactivity and high levels of branched regioselectivity are obtained. We propose that aldehyde decarbonylation is overcome by using an anionic directing group on the olefin and a small bite-angle diphosphine ligand. PMID:24478146

  14. [Functional feeding groups of macroinvertebrates in Gaira river, Colombia].

    PubMed

    Rodríguez-Barrios, Javier; Ospina-Tórres, Rodulfo; Turizo-Correa, Rodrigo

    2011-12-01

    Tropical rivers are frequently described on their biodiversity but few studies have considered the ecological value of this richness in their food webs. We determined the trophic structure of aquatic macroinvertebrate communities (expressed in the richness and abundance of taxa and biomass proportions of different functional feeding groups) at the level of the river, stretch and microhabitats (functional units - UFs). We evaluated the spatial and temporal variation of these descriptors during wet and dry events, and selected three sites associated with different altitudinal belts. We reported 109 taxa, with 11167 individuals who contributed 107.11g of biomass. Density of macroinvertebrates was favored with increasing height, and biomass showed the opposite pattern (K-W = 10.1, d.f. = 1, p < 0.05), due to the addition of large crustaceans (Macrobrachium), and the taxa diversity was higher in the middle stretch of the river (H'=3.16). The Gaira stream runs through a mid-sized river basin, for this reason we found mainly bedrock (epilithon = 50.5%), gravel and sand (43.7%). The functional unit with more habitat and food resources that contains a higher abundance of leaf litter macroinvertebrates was foliage followed by epilithon, fine sediment and gravel-sand (K-W = 25.3, d.f. = 3, p < 0.05). The biomass values of these organisms were higher in leaves followed by gravel-sands, epilithon and sediment (K-W = 15.3, d.f. = 3, p < 0.05). Autochthonous biomass input by different functional feeding groups can be considered very low, but they define the functionality of the stream, being represented almost exclusively by shredders (Macrobrachium, 73%), present only in the lower reaches, followed by shredder Leptonema with 15%, located mostly in the upper reaches and predatory stoneflies of the genus Anacroneuria to 6.56%, which dominated in the middle stretch of stream. Excluding Macrobrachium from the analysis, there was dominance of Anacroneuria in the lower reaches

  15. Residues that influence coenzyme preference in the aldehyde dehydrogenases.

    PubMed

    González-Segura, Lilian; Riveros-Rosas, Héctor; Julián-Sánchez, Adriana; Muñoz-Clares, Rosario A

    2015-06-05

    To find out the residues that influence the coenzyme preference of aldehyde dehydrogenases (ALDHs), we reviewed, analyzed and correlated data from their known crystal structures and amino-acid sequences with their published kinetic parameters for NAD(P)(+). We found that the conformation of the Rossmann-fold loops participating in binding the adenosine ribose is very conserved among ALDHs, so that coenzyme specificity is mainly determined by the nature of the residue at position 195 (human ALDH2 numbering). Enzymes with glutamate or proline at 195 prefer NAD(+) because the side-chains of these residues electrostatically and/or sterically repel the 2'-phosphate group of NADP(+). But contrary to the conformational rigidity of proline, the conformational flexibility of glutamate may allow NADP(+)-binding in some enzymes by moving the carboxyl group away from the 2'-phosphate group, which is possible if a small neutral residue is located at position 224, and favored if the residue at position 53 interacts with Glu195 in a NADP(+)-compatible conformation. Of the residues found at position 195, only glutamate interacts with the NAD(+)-adenosine ribose; glutamine and histidine cannot since their side-chain points are opposite to the ribose, probably because the absence of the electrostatic attraction by the conserved nearby Lys192, or its electrostatic repulsion, respectively. The shorter side-chains of other residues-aspartate, serine, threonine, alanine, valine, leucine, or isoleucine-are distant from the ribose but leave room for binding the 2'-phosphate group. Generally, enzymes having a residue different from Glu bind NAD(+) with less affinity, but they can also bind NADP(+) even sometimes with higher affinity than NAD(+), as do enzymes containing Thr/Ser/Gln195. Coenzyme preference is a variable feature within many ALDH families, consistent with being mainly dependent on a single residue that apparently has no other structural or functional roles, and therefore can

  16. Organized thiol functional groups in mesoporous core shell colloids

    SciTech Connect

    Marchena, Martin H.; Granada, Mara; Bordoni, Andrea V.; Joselevich, Maria; Troiani, Horacio; Williams, Federico J.; Wolosiuk, Alejandro

    2012-03-15

    The co-condensation in situ of tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS) using cetyltrimethylammonium bromide (CTAB) as a template results in the synthesis of multilayered mesoporous structured SiO{sub 2} colloids with 'onion-like' chemical environments. Thiol groups were anchored to an inner selected SiO{sub 2} porous layer in a bilayered core shell particle producing different chemical regions inside the colloidal layered structure. X-Ray Photoelectron Spectroscopy (XPS) shows a preferential anchoring of the -SH groups in the double layer shell system, while porosimetry and simple chemical modifications confirm that pores are accessible. We can envision the synthesis of interesting colloidal objects with defined chemical environments with highly controlled properties. - Graphical abstract: Mesoporous core shell SiO{sub 2} colloids with organized thiol groups. Highlights: Black-Right-Pointing-Pointer Double shell mesoporous silica colloids templated with CTAB. Black-Right-Pointing-Pointer Sequential deposition of mesoporous SiO{sub 2} layers with different chemistries. Black-Right-Pointing-Pointer XPS shows the selective functionalization of mesoporous layers with thiol groups.

  17. Acaricidal effects of natural six-carbon and nine-carbon aldehydes on stored-product mites.

    PubMed

    Hubert, Jan; Münzbergová, Zuzana; Nesvorná, Marta; Poltronieri, Palmiro; Santino, Angelo

    2008-04-01

    The toxicities of three plant volatiles, (2E)-hexenal, (2E, 6Z)-nonadienal and (2E)-nonenal, intermediate products of the oxylipin biosynthesis pathway, were tested on three mites of importance for medical purposes and as pests. The aldehydes were diluted in hexane separately and incorporated into diets in ranges of 4-143 mg g(-1). The final density of mites in control and aldehyde-enriched diets was compared after 21 days. The aldehydes were toxic to the mites, whose final density showed an inverse correlation with aldehyde concentration. In addition to the effects of aldehyde concentration, the final density of mites was also influenced by the different aldehydes tested and the interaction among aldehyde concentration and chemical structure. In a functional combination of aldehydes and species, the doses calculated for growth inhibition and eradication of mites ranged from 4 to 35 mg g(-1) and from 36 to 314 mg g(-1), respectively. Due to the protective role displayed by natural six-carbon and nine-carbon aldehydes, these compounds are potential candidates for controlling stored-product mites in stored food and feed products.

  18. Finding sequence motifs in groups of functionally related proteins.

    PubMed

    Smith, H O; Annau, T M; Chandrasegaran, S

    1990-01-01

    We have developed a method for rapidly finding patterns of conserved amino acid residues (motifs) in groups of functionally related proteins. All 3-amino acid patterns in a group of proteins of the type aa1 d1 aa2 d2 aa3, where d1 and d2 are distances that can be varied in a range up to 24 residues, are accumulated into an array. Segments of the proteins containing those patterns that occur most frequently are aligned on each other by a scoring method that obtains an average relatedness value for all the amino acids in each column of the aligned sequence block based on the Dayhoff relatedness odds matrix. The automated method successfully finds and displays nearly all of the sequence motifs that have been previously reported to occur in 33 reverse transcriptases, 18 DNA integrases, and 30 DNA methyltransferases.

  19. Functional renormalization group study of nuclear and neutron matter

    SciTech Connect

    Drews, Matthias; Weise, Wolfram

    2016-01-22

    A chiral model based on nucleons interacting via boson exchange is investigated. Fluctuation effects are included consistently beyond the mean-field approximation in the framework of the functional renormalization group. The liquid-gas phase transition of symmetric nuclear matter is studied in detail. No sign of a chiral restoration transition is found up to temperatures of about 100 MeV and densities of at least three times the density of normal nuclear matter. Moreover, the model is extended to asymmetric nuclear matter and the constraints from neutron star observations are discussed.

  20. The theoretical and experimental study on dicalcium phosphate dehydrate loading with protocatechuic aldehyde.

    PubMed

    Guo, Yuehua; Qu, Shuxin; Lu, Xiong; Xie, Haodong; Zhang, Hongping; Weng, Jie

    2010-07-01

    The aim of this study is to investigate the interaction between dicalcium phosphate dihydrate (CaHPO(4) x 2H(2)O, DCPD) and Protocatechuic aldehyde (C(7)H(6)O(3), Pca), which is the water-soluble constituents of Chinese Medicine, Salvia Miltiorrhiza Bunge (SMB), by calculating the absorption energy through molecular dynamics simulation. Furthermore, the effects of functional groups of Pca and temperature on Pca adsorbed by DCPD are calculated respectively. DCPD/Pca and DCPD were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TG). The simulation results showed that Pca mostly absorbed on the (0 2 0) surface of DCPD. The aldehyde group of Pca played a moren important role on the adsorption of Pca on DCPD than hydroxyl did, while temperature had no distinct effects on the adsorption. XRD results indicated that Pca induced the preferential growth of (0 2 0) crystal surface in DCPC/Pca whereas it had no influence on the crystal structure, the crystallinity and grain size of DCPD. FTIR and TG results showed that the characteristic peak of Pca was at 1295 cm(-1) and the content of Pca in DCPD was 16%, respectively. The present results show that molecular dynamics simulation is a very effective and complementary method to study the interaction between materials and medicine.

  1. Brain, liver and plasma unsaturated aldehydes in nutritional encephalomalacia of chicks.

    PubMed

    Fuhrmann, H; Sallmann, H P

    2000-04-01

    Vitamin E deficiency and linoleic acid-feeding lead to nutritional encephalomalacia (NE) in chicks, affecting the cerebellum exclusively. The relevance of lipid peroxidation (LPO) products to the pathogenesis of the disease was studied. Laying hens received a diet low in vitamin E. Resulting chicks were assigned to four groups fed either with linoleic (C18: 2n-6) or linolenic (C18: 3n-3) acid together with 1 or 50 p.p.m. vitamin E. Nine days post-hatching NE occurred in the vitamin E-deficient group fed linoleic acid. With each chick showing NE, a healthy one from all four groups was killed. Unsaturated aldehydes were determined in plasma, liver, cerebrum and cerebellum. Results underlined that the type of dietary fat is decisive for the aldehyde pattern. In the liver of linoleic acid-fed animals total aldehydes were increased. Diseased animals had increased aldehydes stemming from n-3 fatty acids. In plasma, vitamin E deficiency led to higher malondialdehyde and OH-nonenal concentrations. In brain, neither vitamin E deficiency nor NE were accompanied by increased aldehyde concentrations. In consequence a direct role of unsaturated aldehydes for the development of NE in the cerebellum is not probable.

  2. Photoredox Activation for the Direct β-Arylation of Ketones and Aldehydes

    PubMed Central

    Pirnot, Michael T.; Rankic, Danica A.; Martin, David B. C.; MacMillan, David W. C.

    2013-01-01

    The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a broad range of carbonyl β-functionalization reactions and is amenable to enantioselective catalysis. PMID:23539600

  3. Copper(II)/amine synergistically catalyzed enantioselective alkylation of cyclic N-acyl hemiaminals with aldehydes.

    PubMed

    Sun, Shutao; Mao, Ying; Lou, Hongxiang; Liu, Lei

    2015-07-07

    The first catalytic asymmetric alkylation of N-acyl quinoliniums with aldehydes has been described. A copper/amine synergistic catalytic system has been developed, allowing the addition of functionalized aldehydes to a wide range of electronically varied N-acyl quinoliniums in good yields with excellent enantiocontrol. The synergistic catalytic system was also effective for N-acyl dihydroisoquinoliniums and β-caboliniums, demonstrating the general applicability of the protocol in the enantioselective alkylation of diverse cyclic N-acyl hemiaminals.

  4. ESG: extended similarity group method for automated protein function prediction

    PubMed Central

    Chitale, Meghana; Hawkins, Troy; Park, Changsoon; Kihara, Daisuke

    2009-01-01

    Motivation: Importance of accurate automatic protein function prediction is ever increasing in the face of a large number of newly sequenced genomes and proteomics data that are awaiting biological interpretation. Conventional methods have focused on high sequence similarity-based annotation transfer which relies on the concept of homology. However, many cases have been reported that simple transfer of function from top hits of a homology search causes erroneous annotation. New methods are required to handle the sequence similarity in a more robust way to combine together signals from strongly and weakly similar proteins for effectively predicting function for unknown proteins with high reliability. Results: We present the extended similarity group (ESG) method, which performs iterative sequence database searches and annotates a query sequence with Gene Ontology terms. Each annotation is assigned with probability based on its relative similarity score with the multiple-level neighbors in the protein similarity graph. We will depict how the statistical framework of ESG improves the prediction accuracy by iteratively taking into account the neighborhood of query protein in the sequence similarity space. ESG outperforms conventional PSI-BLAST and the protein function prediction (PFP) algorithm. It is found that the iterative search is effective in capturing multiple-domains in a query protein, enabling accurately predicting several functions which originate from different domains. Availability: ESG web server is available for automated protein function prediction at http://dragon.bio.purdue.edu/ESG/ Contact: cspark@cau.ac.kr; dkihara@purdue.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:19435743

  5. Expression pattern, ethanol-metabolizing activities, and cellular localization of alcohol and aldehyde dehydrogenases in human large bowel: association of the functional polymorphisms of ADH and ALDH genes with hemorrhoids and colorectal cancer.

    PubMed

    Chiang, Chien-Ping; Jao, Shu-Wen; Lee, Shiao-Pieng; Chen, Pei-Chi; Chung, Chia-Chi; Lee, Shou-Lun; Nieh, Shin; Yin, Shih-Jiun

    2012-02-01

    Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are principal enzymes responsible for metabolism of ethanol. Functional polymorphisms of ADH1B, ADH1C, and ALDH2 genes occur among racial populations. The goal of this study was to systematically determine the functional expressions and cellular localization of ADHs and ALDHs in human rectal mucosa, the lesions of adenocarcinoma and hemorrhoid, and the genetic association of allelic variations of ADH and ALDH with large bowel disorders. Twenty-one surgical specimens of rectal adenocarcinoma and the adjacent normal mucosa, including 16 paired tissues of rectal tumor, normal mucosae of rectum and sigmoid colon from the same individuals, and 18 surgical mixed hemorrhoid specimens and leukocyte DNA samples from 103 colorectal cancer patients, 67 hemorrhoid patients, and 545 control subjects recruited in previous study, were investigated. The isozyme/allozyme expression patterns of ADH and ALDH were identified by isoelectric focusing and the activities were assayed spectrophotometrically. The protein contents of ADH/ALDH isozymes were determined by immunoblotting using the corresponding purified class-specific antibodies; the cellular activity and protein localizations were detected by immunohistochemistry and histochemistry, respectively. Genotypes of ADH1B, ADH1C, and ALDH2 were determined by polymerase chain reaction-restriction fragment length polymorphisms. At 33mM ethanol, pH 7.5, the activity of ADH1C*1/1 phenotypes exhibited 87% higher than that of the ADH1C*1/*2 phenotypes in normal rectal mucosa. The activity of ALDH2-active phenotypes of rectal mucosa was 33% greater than ALDH2-inactive phenotypes at 200μM acetaldehyde. The protein contents in normal rectal mucosa were in the following order: ADH1>ALDH2>ADH3≈ALDH1A1, whereas those of ADH2, ADH4, and ALDH3A1 were fairly low. Both activity and content of ADH1 were significantly decreased in rectal tumors, whereas the ALDH activity remained

  6. FTIR Analysis of Functional Groups in Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Shokri, S. M.; McKenzie, G.; Dransfield, T. J.

    2012-12-01

    Secondary organic aerosols (SOA) are suspensions of particulate matter composed of compounds formed from chemical reactions of organic species in the atmosphere. Atmospheric particulate matter can have impacts on climate, the environment and human health. Standardized techniques to analyze the characteristics and composition of complex secondary organic aerosols are necessary to further investigate the formation of SOA and provide a better understanding of the reaction pathways of organic species in the atmosphere. While Aerosol Mass Spectrometry (AMS) can provide detailed information about the elemental composition of a sample, it reveals little about the chemical moieties which make up the particles. This work probes aerosol particles deposited on Teflon filters using FTIR, based on the protocols of Russell, et al. (Journal of Geophysical Research - Atmospheres, 114, 2009) and the spectral fitting algorithm of Takahama, et al (submitted, 2012). To validate the necessary calibration curves for the analysis of complex samples, primary aerosols of key compounds (e.g., citric acid, ammonium sulfate, sodium benzoate) were generated, and the accumulated masses of the aerosol samples were related to their IR absorption intensity. These validated calibration curves were then used to classify and quantify functional groups in SOA samples generated in chamber studies by MIT's Kroll group. The fitting algorithm currently quantifies the following functionalities: alcohols, alkanes, alkenes, amines, aromatics, carbonyls and carboxylic acids.

  7. Aldehyde Dehydrogenases in Cellular Responses to Oxidative/electrophilic Stress

    PubMed Central

    Singh, Surendra; Brocker, Chad; Koppaka, Vindhya; Ying, Chen; Jackson, Brian; Matsumoto, Akiko; Thompson, David C.; Vasiliou, Vasilis

    2013-01-01

    Reactive oxygen species (ROS) are continuously generated within living systems and the inability to manage ROS load leads to elevated oxidative stress and cell damage. Oxidative stress is coupled to the oxidative degradation of lipid membranes, also known as lipid peroxidation. This process generates over 200 types of aldehydes, many of which are highly reactive and toxic. Aldehyde dehydrogenases (ALDHs) metabolize endogenous and exogenous aldehydes and thereby mitigate oxidative/electrophilic stress in prokaryotic and eukaryotic organisms. ALDHs are found throughout the evolutionary gamut, from single celled organisms to complex multicellular species. Not surprisingly, many ALDHs in evolutionarily distant, and seemingly unrelated, species perform similar functions, including protection against a variety of environmental stressors like dehydration and ultraviolet radiation. The ability to act as an ‘aldehyde scavenger’ during lipid peroxidation is another ostensibly universal ALDH function found across species. Up-regulation of ALDHs is a stress response in bacteria (environmental and chemical stress), plants (dehydration, salinity and oxidative stress), yeast (ethanol exposure and oxidative stress), Caenorhabditis elegans (lipid peroxidation) and mammals (oxidative stress and lipid peroxidation). Recent studies have also identified ALDH activity as an important feature of cancer stem cells. In these cells, ALDH expression helps abrogate oxidative stress and imparts resistance against chemotherapeutic agents such as oxazaphosphorine, taxane and platinum drugs. The ALDH superfamily represents a fundamentally important class of enzymes that significantly contributes to the management of electrophilic/oxidative stress within living systems. Mutations in various ALDHs are associated with a variety of pathological conditions in humans, underscoring the fundamental importance of these enzymes in physiological and pathological processes. PMID:23195683

  8. A method to quantify organic functional groups and inorganic compounds in ambient aerosols using attenuated total reflectance FTIR spectroscopy and multivariate chemometric techniques

    NASA Astrophysics Data System (ADS)

    Coury, Charity; Dillner, Ann M.

    An attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopic technique and a multivariate calibration method were developed to quantify ambient aerosol organic functional groups and inorganic compounds. These methods were applied to size-resolved particulate matter samples collected in winter and summer of 2004 at three sites: a downtown Phoenix, Arizona location, a rural site near Phoenix, and an urban fringe site between the urban and rural site. Ten organic compound classes, including four classes which contain a carbonyl functional group, and three inorganic species were identified in the ambient samples. A partial least squares calibration was developed and applied to the ambient spectra, and 13 functional groups related to organic compounds (aliphatic and aromatic CH, methylene, methyl, alkene, aldehydes/ketones, carboxylic acids, esters/lactones, acid anhydrides, carbohydrate hydroxyl and ethers, amino acids, and amines) as well as ammonium sulfate and ammonium nitrate were quantified. Comparison of the sum of the mass measured by the ATR-FTIR technique and gravimetric mass indicates that this method can quantify nearly all of the aerosol mass on sub-micrometer size-segregated samples. Analysis of sample results shows that differences in organic functional group and inorganic compound concentrations at the three sampling sites can be measured with these methods. Future work will analyze the quantified data from these three sites in detail.

  9. Nutrient resorption patterns of plant functional groups in a tropical savanna: variation and functional significance.

    PubMed

    Ratnam, Jayashree; Sankaran, Mahesh; Hanan, Niall P; Grant, Rina C; Zambatis, Nick

    2008-08-01

    Green and senesced leaf nitrogen (N) and phosphorus (P) concentrations of different plant functional groups in savanna communities of Kruger National Park, South Africa were analyzed to determine if nutrient resorption was regulated by plant nutritional status and foliar N:P ratios. The N and P concentrations in green leaves and the N concentrations in senesced leaves differed significantly between the dominant plant functional groups in these savannas: fine-leaved trees, broad-leaved trees and grasses. However, all three functional groups reduced P to comparable and very low levels in senesced leaves, suggesting that P was tightly conserved in this tropical semi-arid savanna ecosystem. Across all functional groups, there was evidence for nutritional control of resorption in this system, with both N and P resorption efficiencies decreasing as green leaf nutrient concentrations increased. However, specific patterns of resorption and the functional relationships between nutrient concentrations in green and senesced leaves varied by nutrient and plant functional group. Functional relationships between N concentrations in green and senesced leaves were indistinguishable between the dominant groups, suggesting that variation in N resorption efficiency was largely the result of inter-life form differences in green leaf N concentrations. In contrast, observed differences in P resorption efficiencies between life forms appear to be the result of both differences in green leaf P concentrations as well as inherent differences between life forms in the fraction of green leaf P resorbed from senescing leaves. Our results indicate that foliar N:P ratios are poor predictors of resorption efficiency in this ecosystem, in contrast to N and P resorption proficiencies, which are more responsive to foliar N:P ratios.

  10. Correlation functions from a unified variational principle: Trial Lie groups

    SciTech Connect

    Balian, R.; Vénéroni, M.

    2015-11-15

    Time-dependent expectation values and correlation functions for many-body quantum systems are evaluated by means of a unified variational principle. It optimizes a generating functional depending on sources associated with the observables of interest. It is built by imposing through Lagrange multipliers constraints that account for the initial state (at equilibrium or off equilibrium) and for the backward Heisenberg evolution of the observables. The trial objects are respectively akin to a density operator and to an operator involving the observables of interest and the sources. We work out here the case where trial spaces constitute Lie groups. This choice reduces the original degrees of freedom to those of the underlying Lie algebra, consisting of simple observables; the resulting objects are labeled by the indices of a basis of this algebra. Explicit results are obtained by expanding in powers of the sources. Zeroth and first orders provide thermodynamic quantities and expectation values in the form of mean-field approximations, with dynamical equations having a classical Lie–Poisson structure. At second order, the variational expression for two-time correlation functions separates–as does its exact counterpart–the approximate dynamics of the observables from the approximate correlations in the initial state. Two building blocks are involved: (i) a commutation matrix which stems from the structure constants of the Lie algebra; and (ii) the second-derivative matrix of a free-energy function. The diagonalization of both matrices, required for practical calculations, is worked out, in a way analogous to the standard RPA. The ensuing structure of the variational formulae is the same as for a system of non-interacting bosons (or of harmonic oscillators) plus, at non-zero temperature, classical Gaussian variables. This property is explained by mapping the original Lie algebra onto a simpler Lie algebra. The results, valid for any trial Lie group, fulfill

  11. Functional Group Analysis of Biomass Burning Particles Using Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Horrell, K.; Lau, A.; Bond, T.; Iraci, L. T.

    2008-12-01

    Biomass burning is a significant source of particulate organic carbon in the atmosphere. These particles affect the energy balance of the atmosphere directly by absorbing and scattering solar radiation, and indirectly through their ability to act as cloud condensation nuclei (CCN). The chemical composition of biomass burning particles influences their ability to act as CCN, thus understanding the chemistry of these particles is required for understanding their effects on climate and air quality. As climate change influences the frequency and severity of boreal forest fires, the influence of biomass burning aerosols on the atmosphere may become significantly greater. Only a small portion of the organic carbon (OC) fraction of these particles has been identified at the molecular level, although several studies have explored the general chemical classes found in biomass burning smoke. To complement those studies and provide additional information about the reactive functional groups present, we are developing a method for polarity-based separation of compound classes found in the OC fraction, followed by infrared (IR) spectroscopic analysis of each polarity fraction. It is our goal to find a simple, relatively low-tech method which will provide a moderate chemical understanding of the entire suite of compounds present in the OC fraction of biomass burning particles. Here we present preliminary results from pine and oak samples representative of Midwestern United States forests burned at several different temperatures. Wood type and combustion temperature are both seen to affect the composition of the particles. The latter seems to affect relative contributions of certain functional groups, while oak demonstrates at least one additional chemical class of compounds, particularly at lower burning temperatures, where gradual solid-gas phase reactions can produce relatively large amounts of incompletely oxidized products.

  12. Peptide aldehyde inhibitors of hepatitis A virus 3C proteinase.

    PubMed

    Malcolm, B A; Lowe, C; Shechosky, S; McKay, R T; Yang, C C; Shah, V J; Simon, R J; Vederas, J C; Santi, D V

    1995-06-27

    Picornaviral 3C proteinases are a group of closely related thiol proteinases responsible for processing of the viral polyprotein into its component proteins. These proteinases adopt a chymotrypsin-like fold [Allaire et al. (1994) Nature 369, 72-77; Matthews et al. (1994) Cell 77, 761-771] and a display an active-site configuration like those of the serine proteinases. Peptide-aldehydes based on the preferred peptide substrates for hepatitis A virus (HAV) 3C proteinase were synthesized by reduction of a thioester precursor. Acetyl-Leu-Ala-Ala-(N,N'-dimethylglutaminal) was found to be a reversible, slow-binding inhibitor for HAV 3C with a Ki* of (4.2 +/- 0.8) x 10(-8) M. This inhibitor showed 50-fold less activity against the highly homologous human rhinovirus (strain 14) 3C proteinase, whose peptide substrate specificity is slightly different, suggesting a high degree of selectivity. NMR spectrometry of the adduct of the 13C-labeled inhibitor with the HAV-3C proteinase indicate that a thiohemiacetal is formed between the enzyme and the aldehyde carbon as previously noted for peptide-aldehyde inhibitors of papain [Lewis & Wolfenden (1977) Biochemistry 16,4890-4894; Gamcsik et al. (1983) J. Am. Chem. Soc. 105, 6324-6325]. The adduct can also be observed by electrospray mass spectrometry.

  13. Pd(II)-Catalyzed C–H Functionalizations Directed by Distal Weakly Coordinating Functional Groups

    PubMed Central

    Li, Gang; Wan, Li; Zhang, Guofu; Leow, Dasheng; Spangler, Jillian

    2015-01-01

    Ortho-C(sp2)–H olefination and acetoxylation of broadly useful synthetic building blocks phenylacetyl Weinreb amides, esters, and ketones are developed without installing an additional directing group. The interplay between the distal weak coordination and the ligand-acceleration is crucial for these reactions to proceed under mild conditions. The tolerance of longer distance between the target C–H bonds and the directing functional groups also allows for the functionalizations of more distal C–H bonds in hydrocinnamoyl ketones, Weinreb amides and biphenyl Weinreb amides. Mechanistically, the coordination of these carbonyl groups and the bisdentate amino acid ligand with Pd(II) centers provides further evidence for our early hypothesis that the carbonyl groups of the potassium carboxylate is responsible for the directed C–H activation of carboxylic acids. PMID:25768039

  14. Functional renormalization group studies of nuclear and neutron matter

    NASA Astrophysics Data System (ADS)

    Drews, Matthias; Weise, Wolfram

    2017-03-01

    Functional renormalization group (FRG) methods applied to calculations of isospin-symmetric and asymmetric nuclear matter as well as neutron matter are reviewed. The approach is based on a chiral Lagrangian expressed in terms of nucleon and meson degrees of freedom as appropriate for the hadronic phase of QCD with spontaneously broken chiral symmetry. Fluctuations beyond mean-field approximation are treated solving Wetterich's FRG flow equations. Nuclear thermodynamics and the nuclear liquid-gas phase transition are investigated in detail, both in symmetric matter and as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of symmetric nuclear matter and pure neutron matter are found to be in good agreement with advanced ab-initio many-body computations. Contacts with perturbative many-body approaches (in-medium chiral perturbation theory) are discussed. As an interesting test case, the density dependence of the pion mass in the medium is investigated. The question of chiral symmetry restoration in nuclear and neutron matter is addressed. A stabilization of the phase with spontaneously broken chiral symmetry is found to persist up to high baryon densities once fluctuations beyond mean-field are included. Neutron star matter including beta equilibrium is discussed under the aspect of the constraints imposed by the existence of two-solar-mass neutron stars.

  15. Two-carbon homologation of aldehydes and ketones to a,ß-unsaturated aldehydes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphonate reagents were developed for the two-carbon homologation of aldehydes or ketones to unbranched- or methyl-branched a,ß-unsaturated aldehydes. The phosphonate reagents, diethyl methylformyl-2-phosphonate dimethylhydrazone and diethyl ethylformyl-2-phosphonate dimethylhydrazone, contained a...

  16. EFFECT OF FUNCTIONAL GROUP CONFORMATION ON THE INFRARED SPECTRA OF SOME GEM DIFUNCTIONAL PHENYLETHYLENE DERIVATIVES,

    DTIC Science & Technology

    each functional group . The two bands for similar functional groups have been ascribed to S-cis- and S-trans- conformations of the carbonyl groups with...Except for the benzalmalononitriles, two functional group stretching vibrations occur in the infrared (i.r.) spectra of the beta,beta-difunctional...styrenes with similar functional groups . For geometrically homogeneous compounds with dissimilar functional groups only one absorption band occurs for

  17. Observations of Adolescent Peer Group Interactions as a Function of Within- and Between-Group Centrality Status

    ERIC Educational Resources Information Center

    Ellis, Wendy E.; Dumas, Tara M.; Mahdy, Jasmine C.; Wolfe, David A.

    2012-01-01

    Observations of adolescent (n = 258; M age = 15.45) peer group triads (n = 86) were analyzed to identify conversation and interaction styles as a function of within-group and between-group centrality status. Group members' discussions about hypothetical dilemmas were coded for agreements, disagreements, commands, and opinions. Interactions during…

  18. Nuclear alkylated pyridine aldehyde polymers and conductive compositions thereof

    NASA Technical Reports Server (NTRS)

    Rembaum, A.; Singer, S. (Inventor)

    1970-01-01

    A thermally stable, relatively conductive polymer was disclosed. The polymer was synthesized by condensing in the presence of catalyst a 2, 4, or 6 nuclear alklylated 2, 3, or 4 pyridine aldehyde or quaternary derivatives thereof to form a polymer. The pyridine groups were liked by olefinic groups between 2-4, 2-6, 2-3, 3-4, 3-6 or 4-6 positions. Conductive compositions were prepared by dissolving the quaternary polymer and an organic charge transfer complexing agent such as TCNQ in a mutual solvent such as methanol.

  19. Henry's law constants of some environmentally important aldehydes

    SciTech Connect

    Betterton, E.A.; Hoffmann, M.R.

    1988-12-01

    The Henry's law constants of seven aldehydes have been determined as a function of temperature by bubble-column and by head-space techniques. The compounds were chosen for their potential importance in the polluted troposphere and to allow structure-reactivity patterns to be investigated. The results (at 25/degree/C) are as follows (in units of M atm/sup /minus/1/): chloral, 3.44 /times/ 10/sup 5/; glyoxal, greater than or equal to3 /times/ 10/sup 5/; methylglyoxal, 3.71 /times/ 10/sup 3/; formaldehyde, 2.97 /times/ 10/sup 3/; benzaldehyde, 3.74 /times/ 10/sup 1/; hydroxyacetaldehyde, 4.14 /times/ 10/sup 4/; acetaldehyde, 1.14 /times/ 10/sup 1/. A plot of Taft's parameter, ..sigma..sigma*, vs log H* (the apparent Henry's law constant) gives a straight line with a slope of 1.72. H* for formaldehyde is anomalously high, as expected, but the extremely high value for hydroxyacetaldehyde was unexpected and may indicate that ..cap alpha..-hydroxy-substituted aldehydes could have an usually high affinity for the aqueous phase. The intrinsic Henry's law constants, H, corrected for hydration, do not show a clear structure-reactivity pattern for this series of aldehydes.

  20. Non-specific recognition in phagocytosis: ingestion of aldehyde-treated erythrocytes by rat peritoneal macrophages.

    PubMed Central

    Capo, C; Bongrand, P; Benoliel, A M; Depieds, R

    1979-01-01

    Particles were chemically modified with aldehydes and incubated with rat peritoneal cells for phagocytosis. All dialdehydes and lower monaldehydes tested (methanal, ethanal and propanal) made sheep erythrocytes phagocytosable. Failure of higher monaldehydes to induce phagocytosis of treated erythrocytes was not due to lack of reactivity with red cell membranes. All erythrocytes tested (bird and mammal red cells were used) and rat thymocytes were phagocytosed by rat macrophages after incubation with aldehyde. Treatment of Candida albicans did not induce phagocytosis: this failure was not due to lack of aldehyde binding (as demonstrated with [14C]-methanal) nor to anti-phagocytic properties of the parasite membrane. Sheep erythrocytes were submitted to enzymatic treatment (pronase, trypsin, neuraminidase) or incubated with succinic anhydride (to block free NH2 groups) or iodacetamide (to block free SH groups) before aldehyde treatment: phagocytosis was not decreased, which suggested that aldehydes did not act by altering some definite surface structure of the treated particles. Treatment of erythrocytes with cross-linking compounds such as tetraazotized o-dianisidine (coupling occurs mainly on tyrosine and histidine residues) or l-ethyl(3-dimethyl aminopropyl) carbodiimide (a bivalent reagent binding free COOH groups) did not induce any substantial phagocytosis of erythrocytes. Phagocytosis of aldehyde treated erythrocytes was partly correlated with hydrophobicity of these cells, as measured with a two-phase partition system. It is concluded that aldehyde-mediated phagocytosis of erythrocytes is mainly due to cross-linking of red cell membrane structures, probably involving free OH groups, which must increase local rigidity and thereby modify hydrophobicity of the red cell surface. Images Figure 1 PMID:437841

  1. Non-specific recognition in phagocytosis: ingestion of aldehyde-treated erythrocytes by rat peritoneal macrophages.

    PubMed

    Capo, C; Bongrand, P; Benoliel, A M; Depieds, R

    1979-03-01

    Particles were chemically modified with aldehydes and incubated with rat peritoneal cells for phagocytosis. All dialdehydes and lower monaldehydes tested (methanal, ethanal and propanal) made sheep erythrocytes phagocytosable. Failure of higher monaldehydes to induce phagocytosis of treated erythrocytes was not due to lack of reactivity with red cell membranes. All erythrocytes tested (bird and mammal red cells were used) and rat thymocytes were phagocytosed by rat macrophages after incubation with aldehyde. Treatment of Candida albicans did not induce phagocytosis: this failure was not due to lack of aldehyde binding (as demonstrated with [14C]-methanal) nor to anti-phagocytic properties of the parasite membrane. Sheep erythrocytes were submitted to enzymatic treatment (pronase, trypsin, neuraminidase) or incubated with succinic anhydride (to block free NH2 groups) or iodacetamide (to block free SH groups) before aldehyde treatment: phagocytosis was not decreased, which suggested that aldehydes did not act by altering some definite surface structure of the treated particles. Treatment of erythrocytes with cross-linking compounds such as tetraazotized o-dianisidine (coupling occurs mainly on tyrosine and histidine residues) or l-ethyl(3-dimethyl aminopropyl) carbodiimide (a bivalent reagent binding free COOH groups) did not induce any substantial phagocytosis of erythrocytes. Phagocytosis of aldehyde treated erythrocytes was partly correlated with hydrophobicity of these cells, as measured with a two-phase partition system. It is concluded that aldehyde-mediated phagocytosis of erythrocytes is mainly due to cross-linking of red cell membrane structures, probably involving free OH groups, which must increase local rigidity and thereby modify hydrophobicity of the red cell surface.

  2. Fatty aldehyde dehydrogenases in Acinetobacter sp. strain HO1-N: role in hexadecanol metabolism.

    PubMed Central

    Singer, M E; Finnerty, W R

    1985-01-01

    The role of fatty aldehyde dehydrogenases (FALDHs) in hexadecane and hexadecanol metabolism was studied in Acinetobacter sp. strain HO1-N. Two distinct FALDHs were demonstrated in Acinetobacter sp. strain HO1-N: a membrane-bound, NADP-dependent FALDH activity induced 5-, 15-, and 9-fold by growth on hexadecanol, dodecyl aldehyde, and hexadecane, respectively, and a constitutive, NAD-dependent, membrane-localized FALDH. The NADP-dependent FALDH exhibited apparent Km and Vmax values for decyl aldehyde of 5.0, 13.0, 18.0, and 18.3 microM and 537.0, 500.0, 25.0, and 38.0 nmol/min in hexadecane-, hexadecanol-, ethanol-, palmitate-grown cells, respectively. FALDH isozymes ald-a, ald-b, and ald-c were demonstrated by gel electrophoresis in extracts of hexadecane- and hexadecanol-grown cells. ald-a, ald-b, and ald-d were present in dodecyl aldehyde-grown cells, while palmitate-grown control cells contained ald-b and ald-d. Dodecyl aldehyde-negative mutants were isolated and grouped into two phenotypic classes based on growth: class 1 mutants were hexadecane and hexadecanol negative and class 2 mutants were hexadecane and hexadecanol positive. Specific activity of NADP-dependent FALDH in Ald21 (class 1 mutant) was 85% lower than that of wild-type FALDH, while the specific activity of Ald24 (class 2 mutant) was 55% greater than that of wild-type FALDH. Ald21R, a dodecyl aldehyde-positive revertant able to grow on hexadecane, hexadecanol, and dodecyl aldehyde, exhibited a 100% increase in the specific activity of the NADP-dependent FALDH. The oxidation of [3H]hexadecane byAld21 yielded the accumulation of 61% more fatty aldehyde than the wild type, while Ald24 accumulated 27% more fatty aldehyde, 95% more fatty alcohol, and 65% more wax ester than the wild type. This study provides genetic and physiological evidence for the role of fatty aldehyde as an essential metabolic intermediate and NADP-dependent FALDH as a key enzyme in the dissimilation of hexadecane, hexadecanol

  3. Changes in bird functional diversity across multiple land uses: interpretations of functional redundancy depend on functional group identity.

    PubMed

    Luck, Gary W; Carter, Andrew; Smallbone, Lisa

    2013-01-01

    Examinations of the impact of land-use change on functional diversity link changes in ecological community structure driven by land modification with the consequences for ecosystem function. Yet, most studies have been small-scale, experimental analyses and primarily focussed on plants. There is a lack of research on fauna communities and at large-scales across multiple land uses. We assessed changes in the functional diversity of bird communities across 24 land uses aligned along an intensification gradient. We tested the hypothesis that functional diversity is higher in less intensively used landscapes, documented changes in diversity using four diversity metrics, and examined how functional diversity varied with species richness to identify levels of functional redundancy. Functional diversity, measured using a dendogram-based metric, increased from high to low intensity land uses, but observed values did not differ significantly from randomly-generated expected values. Values for functional evenness and functional divergence did not vary consistently with land-use intensification, although higher than expected values were mostly recorded in high intensity land uses. A total of 16 land uses had lower than expected values for functional dispersion and these were mostly low intensity native vegetation sites. Relations between functional diversity and bird species richness yielded strikingly different patterns for the entire bird community vs. particular functional groups. For all birds and insectivores, functional evenness, divergence and dispersion showed a linear decline with increasing species richness suggesting substantial functional redundancy across communities. However, for nectarivores, frugivores and carnivores, there was a significant hump-shaped or non-significant positive linear relationship between these functional measures and species richness indicating less redundancy. Hump-shaped relationships signify that the most functionally diverse

  4. Changes in Bird Functional Diversity across Multiple Land Uses: Interpretations of Functional Redundancy Depend on Functional Group Identity

    PubMed Central

    Luck, Gary W.; Carter, Andrew; Smallbone, Lisa

    2013-01-01

    Examinations of the impact of land-use change on functional diversity link changes in ecological community structure driven by land modification with the consequences for ecosystem function. Yet, most studies have been small-scale, experimental analyses and primarily focussed on plants. There is a lack of research on fauna communities and at large-scales across multiple land uses. We assessed changes in the functional diversity of bird communities across 24 land uses aligned along an intensification gradient. We tested the hypothesis that functional diversity is higher in less intensively used landscapes, documented changes in diversity using four diversity metrics, and examined how functional diversity varied with species richness to identify levels of functional redundancy. Functional diversity, measured using a dendogram-based metric, increased from high to low intensity land uses, but observed values did not differ significantly from randomly-generated expected values. Values for functional evenness and functional divergence did not vary consistently with land-use intensification, although higher than expected values were mostly recorded in high intensity land uses. A total of 16 land uses had lower than expected values for functional dispersion and these were mostly low intensity native vegetation sites. Relations between functional diversity and bird species richness yielded strikingly different patterns for the entire bird community vs. particular functional groups. For all birds and insectivores, functional evenness, divergence and dispersion showed a linear decline with increasing species richness suggesting substantial functional redundancy across communities. However, for nectarivores, frugivores and carnivores, there was a significant hump-shaped or non-significant positive linear relationship between these functional measures and species richness indicating less redundancy. Hump-shaped relationships signify that the most functionally diverse

  5. Functional movement screen scores in a group of running athletes.

    PubMed

    Loudon, Janice K; Parkerson-Mitchell, Amy J; Hildebrand, Laurie D; Teague, Connie

    2014-04-01

    The purpose of this study was to determine the mean values of the functional movement screen (FMS) in a group of long-distance runners. The secondary aims were to investigate whether the FMS performance differed between sexes and between young and older runners. Forty-three runners, 16 women (mean age = 33.5 years, height = 165.2 cm, weight = 56.3 kg, and body mass index [BMI] = 20.6) and 27 men (mean age = 39.3 years, height = 177.6 cm, weight = 75.8 kg, and BMI = 24.2) performed the FMS. All the runners were injury-free and ran >30 km·wk. Independent t-tests were performed on the composite scores to examine the differences between men and women and also between young (<40 years) and older runners (>40 years). Contingency tables (2 × 2) were developed for each of the 7 screening tests to further look at the differences in groups for each single test. The χ values were calculated to determine significant differences. Statistical significance was set at p ≤ 0.05. There was no significant difference in the composite score between women and men. There were significant differences between the sexes in the push-up and straight leg test scores, with the women scoring better on each test. A significant difference was found in the composite scores between younger and older runners (p < 0.000). Additional score differences were found for the squat, hurdle step, and in-line lunge tests with the younger runners scoring better. This study provided mean values for the FMS in a cohort of long-distance runners. These values can be used as a reference for comparing FMST scores in other runners who are screened with this tool.

  6. Neurodegeneration and motor dysfunction in mice lacking cytosolic and mitochondrial aldehyde dehydrogenases: implications for Parkinson's disease.

    PubMed

    Wey, Margaret Chia-Ying; Fernandez, Elizabeth; Martinez, Paul Anthony; Sullivan, Patricia; Goldstein, David S; Strong, Randy

    2012-01-01

    Previous studies have reported elevated levels of biogenic aldehydes in the brains of patients with Parkinson's disease (PD). In the brain, aldehydes are primarily detoxified by aldehyde dehydrogenases (ALDH). Reduced ALDH1 expression in surviving midbrain dopamine neurons has been reported in brains of patients who died with PD. In addition, impaired complex I activity, which is well documented in PD, reduces the availability of the NAD(+) co-factor required by multiple ALDH isoforms to catalyze the removal of biogenic aldehydes. We hypothesized that chronically decreased function of multiple aldehyde dehydrogenases consequent to exposure to environmental toxins and/or reduced ALDH expression, plays an important role in the pathophysiology of PD. To address this hypothesis, we generated mice null for Aldh1a1 and Aldh2, the two isoforms known to be expressed in substantia nigra dopamine neurons. Aldh1a1(-/-)×Aldh2(-/-) mice exhibited age-dependent deficits in motor performance assessed by gait analysis and by performance on an accelerating rotarod. Intraperitoneal administration of L-DOPA plus benserazide alleviated the deficits in motor performance. We observed a significant loss of neurons immunoreactive for tyrosine hydroxylase (TH) in the substantia nigra and a reduction of dopamine and metabolites in the striatum of Aldh1a1(-/-)×Aldh2(-/-) mice. We also observed significant increases in biogenic aldehydes reported to be neurotoxic, including 4-hydroxynonenal (4-HNE) and the aldehyde intermediate of dopamine metabolism, 3,4-dihydroxyphenylacetaldehyde (DOPAL). These results support the hypothesis that impaired detoxification of biogenic aldehydes may be important in the pathophysiology of PD and suggest that Aldh1a1(-/-)×Aldh2(-/-) mice may be a useful animal model of PD.

  7. Detoxification of aldehydes by histidine-containing dipeptides: from chemistry to clinical implications

    PubMed Central

    Xie, Zhengzhi; Baba, Shahid P.; Sweeney, Brooke R.; Barski, Oleg A.

    2015-01-01

    Aldehydes are generated by oxidized lipids and carbohydrates at increased levels under conditions of metabolic imbalance and oxidative stress during atherosclerosis, myocardial and cerebral ischemia, diabetes, neurodegenerative diseases and trauma. In most tissues, aldehydes are detoxified by oxidoreductases that catalyze the oxidation or the reduction of aldehydes or enzymatic and nonenzymatic conjugation with low molecular weight thiols and amines, such as glutathione and histidine dipeptides. Histidine dipeptides are present in micromolar to millimolar range in the tissues of vertebrates, where they are involved in a variety of physiological functions such as pH buffering, metal chelation, oxidant and aldehyde scavenging. Histidine dipeptides such as carnosine form Michael adducts with lipid-derived unsaturated aldehydes, and react with carbohydrate-derived oxo- and hydroxy- aldehydes forming products of unknown structure. Although these peptides react with electrophilic molecules at lower rate than glutathione, they can protect glutathione from modification by oxidant and they may be important for aldehyde quenching in glutathione-depleted cells or extracellular space where glutathione is scarce. Consistent with in vitro findings, treatment with carnosine has been shown to diminish ischemic injury, improve glucose control, ameliorate the development of complications in animal models of diabetes and obesity, promote wound healing and decrease atherosclerosis. The protective effects of carnosine have been linked to its anti-oxidant properties, it ability to promote glycolysis, detoxify reactive aldehydes and enhance histamine levels. Thus, treatment with carnosine and related histidine dipeptides may be a promising strategy for the prevention and treatment of diseases associated with high carbonyl load. PMID:23313711

  8. Highly adaptive tests for group differences in brain functional connectivity.

    PubMed

    Kim, Junghi; Pan, Wei

    2015-01-01

    Resting-state functional magnetic resonance imaging (rs-fMRI) and other technologies have been offering evidence and insights showing that altered brain functional networks are associated with neurological illnesses such as Alzheimer's disease. Exploring brain networks of clinical populations compared to those of controls would be a key inquiry to reveal underlying neurological processes related to such illnesses. For such a purpose, group-level inference is a necessary first step in order to establish whether there are any genuinely disrupted brain subnetworks. Such an analysis is also challenging due to the high dimensionality of the parameters in a network model and high noise levels in neuroimaging data. We are still in the early stage of method development as highlighted by Varoquaux and Craddock (2013) that "there is currently no unique solution, but a spectrum of related methods and analytical strategies" to learn and compare brain connectivity. In practice the important issue of how to choose several critical parameters in estimating a network, such as what association measure to use and what is the sparsity of the estimated network, has not been carefully addressed, largely because the answers are unknown yet. For example, even though the choice of tuning parameters in model estimation has been extensively discussed in the literature, as to be shown here, an optimal choice of a parameter for network estimation may not be optimal in the current context of hypothesis testing. Arbitrarily choosing or mis-specifying such parameters may lead to extremely low-powered tests. Here we develop highly adaptive tests to detect group differences in brain connectivity while accounting for unknown optimal choices of some tuning parameters. The proposed tests combine statistical evidence against a null hypothesis from multiple sources across a range of plausible tuning parameter values reflecting uncertainty with the unknown truth. These highly adaptive tests are not only

  9. Highly adaptive tests for group differences in brain functional connectivity

    PubMed Central

    Kim, Junghi; Pan, Wei

    2015-01-01

    Resting-state functional magnetic resonance imaging (rs-fMRI) and other technologies have been offering evidence and insights showing that altered brain functional networks are associated with neurological illnesses such as Alzheimer's disease. Exploring brain networks of clinical populations compared to those of controls would be a key inquiry to reveal underlying neurological processes related to such illnesses. For such a purpose, group-level inference is a necessary first step in order to establish whether there are any genuinely disrupted brain subnetworks. Such an analysis is also challenging due to the high dimensionality of the parameters in a network model and high noise levels in neuroimaging data. We are still in the early stage of method development as highlighted by Varoquaux and Craddock (2013) that “there is currently no unique solution, but a spectrum of related methods and analytical strategies” to learn and compare brain connectivity. In practice the important issue of how to choose several critical parameters in estimating a network, such as what association measure to use and what is the sparsity of the estimated network, has not been carefully addressed, largely because the answers are unknown yet. For example, even though the choice of tuning parameters in model estimation has been extensively discussed in the literature, as to be shown here, an optimal choice of a parameter for network estimation may not be optimal in the current context of hypothesis testing. Arbitrarily choosing or mis-specifying such parameters may lead to extremely low-powered tests. Here we develop highly adaptive tests to detect group differences in brain connectivity while accounting for unknown optimal choices of some tuning parameters. The proposed tests combine statistical evidence against a null hypothesis from multiple sources across a range of plausible tuning parameter values reflecting uncertainty with the unknown truth. These highly adaptive tests are not

  10. Semi-catalytic reduction of secondary amides to imines and aldehydes.

    PubMed

    Lee, Sun-Hwa; Nikonov, Georgii I

    2014-06-21

    Secondary amides can be reduced by silane HSiMe2Ph into imines and aldehydes by a two-stage process involving prior conversion of amides into iminoyl chlorides followed by catalytic reduction mediated by the ruthenium complex [Cp(i-Pr3P)Ru(NCCH3)2]PF6 (1). Alkyl and aryl amides bearing halogen, ketone, and ester groups were converted with moderate to good yields under mild reaction conditions to the corresponding imines and aldehydes. This procedure does not work for substrates bearing the nitro-group and fails for heteroaromatic amides. In the case of cyano substituted amides, the cyano group is reduced to imine.

  11. High-performance functional Renormalization Group calculations for interacting fermions

    NASA Astrophysics Data System (ADS)

    Lichtenstein, J.; Sánchez de la Peña, D.; Rohe, D.; Di Napoli, E.; Honerkamp, C.; Maier, S. A.

    2017-04-01

    We derive a novel computational scheme for functional Renormalization Group (fRG) calculations for interacting fermions on 2D lattices. The scheme is based on the exchange parametrization fRG for the two-fermion interaction, with additional insertions of truncated partitions of unity. These insertions decouple the fermionic propagators from the exchange propagators and lead to a separation of the underlying equations. We demonstrate that this separation is numerically advantageous and may pave the way for refined, large-scale computational investigations even in the case of complex multiband systems. Furthermore, on the basis of speedup data gained from our implementation, it is shown that this new variant facilitates efficient calculations on a large number of multi-core CPUs. We apply the scheme to the t ,t‧ Hubbard model on a square lattice to analyze the convergence of the results with the bond length of the truncation of the partition of unity. In most parameter areas, a fast convergence can be observed. Finally, we compare to previous results in order to relate our approach to other fRG studies.

  12. Intercalation of Aldehydes into Vanadyl Phosphate

    NASA Astrophysics Data System (ADS)

    Melánová, Klára; Beneš, Ludvík.; Zima, Vítězslav; Votinský, Jiří

    2001-02-01

    Intercalates of VOPO4 with several aliphatic aldehydes, benzaldehyde, and 4-methylbenzaldehyde were prepared and characterized by thermogravimetric analysis, X-ray diffractometry, and IR and UV-vis spectroscopies. Aliphatic aldehyde intercalates are unstable and the guests undergo aldol condensation and oxidation. The arrangement of the guest molecules in the interlayer space of the host is discussed. A part of aliphatic aldehydes is anchored to the host layers by coordination of their carbonyl oxygen to the vanadium atom; the rest is probably bonded by weak van der Waals forces. In the benzaldehyde and 4-methylbenzaldehyde intercalates, all guest molecules are coordinated to the vanadium atoms with their benzene rings perpendicular to the sheets of the host.

  13. Betaine aldehyde dehydrogenase isozymes of spinach

    SciTech Connect

    Hanson, A.D.; Weretilnyk, E.A.; Weigel, P.

    1986-04-01

    Betaine is synthesized in spinach chloroplasts via the pathway Choline ..-->.. Betaine Aldehyde ..-->.. Betaine; the second step is catalyzed by betaine aldehyde dehydrogenase (BADH). The subcellular distribution of BADH was determined in leaf protoplast lysates; BADH isozymes were separated by 6-9% native PAGE. The chloroplast stromal fraction contains a single BADH isozyme (number1) that accounts for > 80% of the total protoplast activity; the extrachloroplastic fraction has a minor isozyme (number2) which migrates more slowly than number1. Both isozymes appear specific for betaine aldehyde, are more active with NAD than NADP, and show a ca. 3-fold activity increase in salinized leaves. The phenotype of a natural variant of isozyme number1 suggests that the enzyme is a dimer.

  14. 14 CFR Section 11 - Functional Classification-Operating Expenses of Group II and Group III Air Carriers

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Functional Classification-Operating... ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS Profit and Loss Classification Section 11 Functional Classification—Operating Expenses of Group II and Group III Air Carriers 5100Flying Operations....

  15. Functional trait responses to grazing are mediated by soil moisture and plant functional group identity

    PubMed Central

    Zheng, Shuxia; Li, Wenhuai; Lan, Zhichun; Ren, Haiyan; Wang, Kaibo

    2015-01-01

    Abundant evidence has shown that grazing alters plant functional traits, community structure and ecosystem functioning of grasslands. Few studies, however, have tested how plant responses to grazing are mediated by resource availability and plant functional group identity. We examined the effects of grazing on functional traits across a broad range of species along a soil moisture gradient in Inner Mongolia grassland. Our results showed that trait syndromes of plant size (individual biomass) and shoot growth (leaf N content and leaf density) distinguished plant species responses to grazing. The effects of grazing on functional traits were mediated by soil moisture and dependent on functional group identity. For most species, grazing decreased plant height but increased leaf N and specific leaf area (SLA) along the moisture gradient. Grazing enhanced the community-weighted attributes (leaf NCWM and SLACWM), which were triggered mainly by the positive trait responses of annuals and biennials and perennial grasses, and increased relative abundance of perennial forbs. Our results suggest that grazing-induced species turnover and increased intraspecific trait variability are two drivers for the observed changes in community weighted attributes. The dominant perennial bunchgrasses exhibited mixed tolerance–resistance strategies to grazing and mixed acquisitive–conservative strategies in resource utilization. PMID:26655858

  16. Ecosystem functions and densities of contributing functional groups respond in a different way to chemical stress.

    PubMed

    De Laender, Frederik; Taub, Frieda B; Janssen, Colin R

    2011-12-01

    Understanding whether and to what extent ecosystem functions respond to chemicals is a major challenge in environmental toxicology. The available data gathered by ecosystem-level experiments (micro- and mesocosms) often describe the responses of taxa densities to stress. However, whether these responses are proportional to the responses of associated ecosystem functions to stress is unclear. By combining a carbon budget modeling technique with data from a standardized microcosm experiment with a known community composition, we quantified three ecosystem functions (net primary production [NPP], net mesozooplankton production [NZP], and net bacterial production [NBP]) at three Cu concentrations, with a control. Changes of these ecosystem functions with increasing chemical concentrations were not always proportional to the Cu effects on the densities of the contributing functional groups. For example, Cu treatments decreased mesozooplankton density by 100-fold and increased phytoplankton density 10- to 100-fold while increasing NZP and leaving NPP unaltered. However, in contrast, Cu affected microzooplankton and the associated function (NBP) in a comparable way. We illustrate that differences in the response of phytoplankton/mesozooplankton densities and the associated ecosystem functions to stress occur because functional rates (e.g., photosynthesis rates/ingestion rates) vary among Cu treatments and in time. These variations could be explained by food web ecology but not by direct Cu effects, indicating that ecology may be a useful basis for understanding environmental effects of stressors.

  17. Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions

    PubMed Central

    Lundholm, Jeremy; MacIvor, J. Scott; MacDougall, Zachary; Ranalli, Melissa

    2010-01-01

    Background Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. Methodology/Principal Findings We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Conclusions/Significance Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms

  18. Effects of benthos on sediment transport: difficulties with functional grouping

    NASA Astrophysics Data System (ADS)

    Jumars, P. A.; Nowell, A. R. M.

    No consistent functional grouping of organisms as stabilizers vs destabilizers, respectively decreasing or enhancing erodibility, is possible. Benthic organisms can affect erodibility in particular—and sediment transport in general—via alternation (1) of fluid momentum impinging on the bed, (2) of particle exposure to the flow, (3) of adhesion between particles, and (4) of particle momentum. The net effects of a species or individual on erosion and deposition thresholds or on transport rates are not in general predictable from extant data. Furthermore, they depend upon the context of flow conditions, bed configuration, and community composition into which the organism is set. Separation of organism effects into these four categories does, however, allow their explicit incorporation into DuBoys-type and stochastic sediment dynamic models already in use and thus permits the specification of parameters whose measurement will enhance predictability of sediment transport modes and rates in natural, organism-influenced, marine settings. If the variable of prime concern is the total amount of sediment transported, rather than the frequency of transport events or the spatial pattern of erosion and eposition, and if most transport occurs in rare but intense bouts (e.g., winter storms on boreal continental shelves), then it may be possible to ignore organism effects without major sacrifices in accuracy or precision. Under high transport rates, suspended load effects override organism-produced bottom roughness, abrasion removes adhesives from transporting grains, and transport rates (normalized per unit width of the channel or bed) exceed feeding and pelletization rates. Moreover, at high rates most material transports as suspended load, effectively out of reach of the benthos. The transport rates at which organism effects are overridden, however, remain to be determined. For lower transport rates, foraging theory promises to provide insights into organism effects.

  19. Students' Perceptions of Classroom Group Work as a Function of Group Member Selection

    ERIC Educational Resources Information Center

    Myers, Scott A.

    2012-01-01

    The purpose of this assessment was to examine whether differences exist between students who self-select their classroom work group members and students who are randomly assigned to their classroom work groups in terms of their use of organizational citizenship behaviors with their work group members; their commitment to, trust in, and relational…

  20. Nickel-catalyzed enantioselective alkylative coupling of alkynes and aldehydes: synthesis of chiral allylic alcohols with tetrasubstituted olefins.

    PubMed

    Yang, Yun; Zhu, Shou-Fei; Zhou, Chang-Yue; Zhou, Qi-Lin

    2008-10-29

    A highly efficient nickel-catalyzed asymmetric alkylative coupling of alkynes, aldehydes, and dimethylzinc has been realized by using bulky spirobiindane phosphoramidite ligands, affording allylic alcohols with a tetrasubstituted olefin functionality in high yields, high regioselectivities, and excellent enantioselectivities.

  1. Oxidation of Aromatic Aldehydes Using Oxone

    ERIC Educational Resources Information Center

    Gandhari, Rajani; Maddukuri, Padma P.; Thottumkara, Vinod K.

    2007-01-01

    The experiment demonstrating the feasibility of using water as a solvent for organic reactions which highlights the cost and environmental benefits of its use is presented. The experiment encourages students to think in terms of the reaction mechanism of the oxidation of aldehydes knowing that potassium persulfate is the active oxidant in Oxone…

  2. Biomimetic flavin-catalyzed aldehyde oxidation.

    PubMed

    Murray, Alexander T; Matton, Pascal; Fairhurst, Nathan W G; John, Matthew P; Carbery, David R

    2012-07-20

    The oxidation of alkyl and aryl aldehydes to their corresponding carboxylic acids has been achieved through the action of a biomimetic bridged flavin catalyst. The reaction uses readily available 35% aqueous hydrogen peroxide and is operationally simple. The oxidation is a green and sustainable reaction, obviating chlorinated solvents with minimal byproducts.

  3. Moral Judgment as a Function of Peer Group Interaction

    ERIC Educational Resources Information Center

    Maitland, Karen A.; Goldman, Jacquelin R.

    1974-01-01

    This article presents an investigation into the effects of peer group interaction on moral judgment among 36 male and female eleventh and twelfth graders. The results indicate greater social conflict and pressure in a group discussion induces greater change in the level of moral judgment. (DE)

  4. Perceptual Visual Grouping under Inattention: Electrophysiological Functional Imaging

    ERIC Educational Resources Information Center

    Razpurker-Apfeld, Irene; Pratt, Hillel

    2008-01-01

    Two types of perceptual visual grouping, differing in complexity of shape formation, were examined under inattention. Fourteen participants performed a similarity judgment task concerning two successive briefly presented central targets surrounded by task-irrelevant simple and complex grouping patterns. Event-related potentials (ERPs) were…

  5. Dominant Functional Group Effects on the Invasion Resistance at Different Resource Levels

    PubMed Central

    Wang, Jiang; Ge, Yuan; Zhang, Chong B.; Bai, Yi; Du, Zhao K.

    2013-01-01

    Background Functional group composition may affect invasion in two ways the effect of abundance, i.e. dominance of functional group; and the effect of traits, i.e. identity of functional groups. However, few studies have focused on the role of abundance of functional group on invasion resistance. Moreover, how resource availability influences the role of the dominant functional group in invasion resistance is even less understood. Methodology/Principal Findings In this experiment, we established experimental pots using four different functional groups (annual grass, perennial grass, deciduous shrub or arbor and evergreen shrub or arbor), and the dominant functional group was manipulated. These experimental pots were respectively constructed at different soil nitrogen levels (control and fertilized). After one year of growth, we added seeds of 20 different species (five species per functional group) to the experimental pots. Fertilization significantly increased the overall invasion success, while dominant functional group had little effect on overall invasion success. When invaders were grouped into functional groups, invaders generally had lower success in pots dominated by the same functional group in the control pots. However, individual invaders of the same functional group exhibited different invasion patterns. Fertilization generally increased success of invaders in pots dominated by the same than by another functional group. However, fertilization led to great differences for individual invaders. Conclusions/Significance The results showed that the dominant functional group, independent of functional group identity, had a significant effect on the composition of invaders. We suggest that the limiting similarity hypothesis may be applicable at the functional group level, and limiting similarity may have a limited role for individual invaders as shown by the inconsistent effects of dominant functional group and fertilization. PMID:24167565

  6. Biomarkers of exposure to endogenous oxidative and aldehyde stress.

    PubMed

    Bruce, W Robert; Lee, Owen; Liu, Zhen; Marcon, Norman; Minkin, Salomon; O'Brien, Peter J

    2011-08-01

    We observed an unexpectedly strong association of three different endogenous aldehydes and noted that the association could be explained by multiple reactions in which oxidative stress increased the formation of endogenous aldehydes and endogenous aldehydes increased oxidative stress. These interactions make it reasonable to assess multiple exposures to endogenous oxidative and aldehyde stress with less specific measures such as advanced glycation end-products or protein carbonyls.

  7. Enantioselective Direct α-Amination of Aldehydes via a Photoredox Mechanism: A Strategy for Asymmetric Amine Fragment Coupling

    PubMed Central

    Cecere, Giuseppe; Koenig, Christian M.; Alleva, Jennifer L.

    2013-01-01

    The direct, asymmetric α-amination of aldehydes has been accomplished via a combination of photoredox and organocatalysis. Photon-generated, nitrogen-centered radicals undergo enantioselective α-addition to catalytically formed chiral enamines to directly produce stable α-amino aldehyde adducts bearing synthetically useful amine substitution patterns. Incorporation of a photolabile group on the amine precursor obviates the need to employ a photoredox catalyst in this transformation. Importantly, this photoinduced transformation allows direct and enantioselective access to α-amino aldehyde products that do not require post-reaction manipulation. PMID:23869694

  8. Hydrolysis of organonitrate functional groups in aerosol particles

    SciTech Connect

    Liu, Shang; Shilling, John E.; Song, Chen; Hiranuma, Naruki; Zaveri, Rahul A.; Russell, Lynn M.

    2012-10-19

    Organonitrate (ON) groups are important substituents in secondary organic aerosols. Model simulations and laboratory studies indicate a large fraction of ON groups in aerosol particles, but much lower quantities are observed in the atmosphere. Hydrolysis of ON groups in aerosol particles has been proposed recently. To test this hypothesis, we simulated formation of ON molecules in a reaction chamber under a wide range of relative humidity (0% to 90%). The mass fraction of ON groups (5% to 20% for high-NOx experiments) consistently decreased with increasing relative humidity, which was best explained by hydrolysis of ON groups at a rate of 4 day-1 (lifetime of 6 hours) for reactions under relative humidity greater than 20%. In addition, we found that secondary nitrogen-containing molecules absorb light, with greater absorption under dry and high-NOx conditions. This work provides the first evidence for particle-phase hydrolysis of ON groups, a process that could substantially reduce ON group concentration in the atmosphere.

  9. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Amine aldehyde condensate. 721.639... Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  10. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Amine aldehyde condensate. 721.639... Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  11. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amine aldehyde condensate. 721.639... Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  12. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Amine aldehyde condensate. 721.639... Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  13. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Amine aldehyde condensate. 721.639... Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  14. Aldehyde dehydrogenase 1A1 in stem cells and cancer

    PubMed Central

    Tomita, Hiroyuki; Tanaka, Kaori; Tanaka, Takuji; Hara, Akira

    2016-01-01

    The human genome contains 19 putatively functional aldehyde dehydrogenase (ALDH) genes, which encode enzymes critical for detoxification of endogenous and exogenous aldehyde substrates through NAD(P)+-dependent oxidation. ALDH1 has three main isotypes, ALDH1A1, ALDH1A2, and ALDH1A3, and is a marker of normal tissue stem cells (SC) and cancer stem cells (CSC), where it is involved in self-renewal, differentiation and self-protection. Experiments with murine and human cells indicate that ALDH1 activity, predominantly attributed to isotype ALDH1A1, is tissue- and cancer-specific. High ALDH1 activity and ALDH1A1 overexpression are associated with poor cancer prognosis, though high ALDH1 and ALDH1A1 levels do not always correlate with highly malignant phenotypes and poor clinical outcome. In cancer therapy, ALDH1A1 provides a useful therapeutic CSC target in tissue types that normally do not express high levels of ALDH1A1, including breast, lung, esophagus, colon and stomach. Here we review the functions and mechanisms of ALDH1A1, the key ALDH isozyme linked to SC populations and an important contributor to CSC function in cancers, and we outline its potential in future anticancer strategies. PMID:26783961

  15. Catalytic conversion of aliphatic alcohols on carbon nanomaterials: The roles of structure and surface functional groups

    NASA Astrophysics Data System (ADS)

    Tveritinova, E. A.; Zhitnev, Yu. N.; Chernyak, S. A.; Arkhipova, E. A.; Savilov, S. V.; Lunin, V. V.

    2017-03-01

    Carbon nanomaterials with the structure of graphene and different compositions of the surface groups are used as catalysts for the conversion of C2-C4 aliphatic alcohols. The conversions of ethanol, propanol- 1, propanol-2, butanol-1, butanol-2, and tert-butanol on carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are investigated. Oxidized and nonoxidized multiwalled carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are synthesized. X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning and transmission electronic microscopies, Brunauer-Emmett-Teller method, derivatographic analyses, and the pulsed microcatalytic method are used to characterize comprehensively the prepared catalysts. It was established that all of the investigated carbon nanomaterials (with the exception of nondoped carbon nanoflakes) are bifunctional catalysts for the conversion of aliphatic alcohols, and promote dehydration reactions with the formation of olefins and dehydrogenation reactions with the formation of aldehydes or ketones. Nanoflakes doped with nitrogen are inert with respect to secondary alcohols and tert-butanol. The role of oxygen-containing and nitrogen-containing surface groups, and of the geometrical structure of the carbon matrix of graphene nanocarbon materials in the catalytic conversion of aliphatic alcohols, is revealed. Characteristics of the conversion of aliphatic alcohols that are associated with their structure are identified.

  16. Effects of spatial grouping on the functional response of predators

    USGS Publications Warehouse

    Cosner, C.; DeAngelis, D.L.; Ault, J.S.; Olson, D.B.

    1999-01-01

    A unified mechanistic approach is given for the derivation of various forms of functional response in predator-prey models. The derivation is based on the principle-of-mass action but with the crucial refinement that the nature of the spatial distribution of predators and/or opportunities for predation are taken into account in an implicit way. If the predators are assumed to have a homogeneous spatial distribution, then the derived functional response is prey-dependent. If the predators are assumed to form a dense colony or school in a single (possibly moving) location, or if the region where predators can encounter prey is assumed to be of limited size, then the functional response depends on both predator and prey densities in a manner that reflects feeding interference between predators. Depending on the specific assumptions, the resulting functional response may be of Beddington-DeAngelis type, of Hassell-Varley type, or ratio-dependent.

  17. Nonequilibrium functional renormalization group for interacting quantum systems.

    PubMed

    Jakobs, Severin G; Meden, Volker; Schoeller, Herbert

    2007-10-12

    We propose a nonequilibrium version of functional renormalization within the Keldysh formalism by introducing a complex-valued flow parameter in the Fermi or Bose functions of each reservoir. Our cutoff scheme provides a unified approach to equilibrium and nonequilibrium situations. We apply it to nonequilibrium transport through an interacting quantum wire coupled to two reservoirs and show that the nonequilibrium occupation induces new power law exponents for the conductance.

  18. Aldehyde dehydrogenase activity in Lactococcus chungangensis: Application in cream cheese to reduce aldehyde in alcohol metabolism.

    PubMed

    Konkit, Maytiya; Choi, Woo Jin; Kim, Wonyong

    2016-03-01

    Previous studies have shown that the metabolic capability of colonic microflora may be at least as high as that of the liver or higher than that of the whole human body. Aldehyde dehydrogenase (ALDH) is an enzyme produced by these bacteria that can metabolize acetaldehyde, produce from ethanol to acetate. Lactococcus species, which is commonly used as a starter in dairy products, was recently found to possess the ALDH gene, and the activity of this enzyme was determined. In this study, the ALDH activity of Lactococcus chungangensis CAU 28(T) and 11 other type strains in the genus Lactococcus was studied. Only 5 species, 3 of dairy origin (Lactococcus lactis ssp. lactis KCTC 3769(T), Lactococcus lactis ssp. cremoris KCCM 40699(T), and Lactococcus raffinolactis DSM 20443(T)) and 2 of nondairy origin (Lactococcus fujiensis NJ317(T) and L. chungangensis CAU 28(T)), showed ALDH activity and possessed a gene encoding ALDH. All of these strains were capable of making cream cheese. Among the strains, L. chungangensis produced cream cheese that contained the highest level of ALDH and was found to reduce the level of acetaldehyde in the serum of mice. These results predict a promising role for L. chungangensis CAU28(T) to be used in cheese that can be developed as functional food.

  19. Single amino acid polymorphism in aldehyde dehydrogenase gene superfamily.

    PubMed

    Priyadharshini Christy, J; George Priya Doss, C

    2015-01-01

    The aldehyde dehydrogenase gene superfamily comprises of 19 genes and 3 pseudogenes. These superfamily genes play a vital role in the formation of molecules that are involved in life processes, and detoxification of endogenous and exogenous aldehydes. ALDH superfamily genes associated mutations are implicated in various diseases, such as pyridoxine-dependent seizures, gamma-hydroxybutyric aciduria, type II Hyperprolinemia, Sjogren-Larsson syndrome including cancer and Alzheimer's disease. Accumulation of large DNA variations data especially Single Amino acid Polymorphisms (SAPs) in public databases related to ALDH superfamily genes insisted us to conduct a survey on the disease associated mutations and predict their function impact on protein structure and function. Overall this study provides an update and highlights the importance of pathogenic mutations in associated diseases. Using KD4v and Project HOPE a computational based platform, we summarized all the deleterious properties of SAPs in ALDH superfamily genes by the providing valuable insight into structural alteration rendered due to mutation. We hope this review might provide a way to define the deleteriousness of a SAP and helps to understand the molecular basis of the associated disease and also permits precise diagnosis and treatment in the near future.

  20. Aldehyde-induced xanthine oxidase activity in raw milk.

    PubMed

    Steffensen, Charlotte L; Andersen, Henrik J; Nielsen, Jacob H

    2002-12-04

    In the present study, the aldehyde-induced pro-oxidative activity of xanthine oxidase was followed in an accelerated raw milk system using spin-trap electron spin resonance (ESR) spectroscopy. The aldehydes acetaldehyde, propanal, hexanal, trans-2-hexenal, trans-2-heptenal, trans-2-nonenal, and 3-methyl-2-butenal were all found to initiate radical reactions when added to milk. Formation of superoxide through aldehyde-induced xanthine oxidase activity is suggested as the initial reaction, as all tested aldehydes were shown to trigger superoxide formation in an ultrahigh temperature (UHT) milk model system with added xanthine oxidase. It was found that addition of aldehydes to milk initially increased the ascorbyl radical concentration with a subsequent decay due to ascorbate depletion, which renders the formation of superoxide in milk with added aldehyde. The present study shows for the first time potential acceleration of oxidative events in milk through aldehyde-induced xanthine oxidase activity.

  1. Concentration of simple aldehydes by sulfite-containing double-layer hydroxide minerals: implications for biopoesis

    NASA Technical Reports Server (NTRS)

    Pitsch, S.; Krishnamurthy, R.; Arrhenius, G.; Bada, J. L. (Principal Investigator)

    2000-01-01

    Environmental conditions play an important role in conceptual studies of prebiotically relevant chemical reactions that could have led to functional biomolecules. The necessary source compounds are likely to have been present in dilute solution, raising the question of how to achieve selective concentration and to reach activation. With the assumption of an initial 'RNA World', the questions of production, concentration, and interaction of aldehydes and aldehyde phosphates, potential precursors of sugar phosphates, come into the foreground. As a possible concentration process for simple, uncharged aldehydes, we investigated their adduct formation with sulfite ion bound in the interlayer of positively charged expanding-sheet-structure double-layer hydroxide minerals. Minerals of this type, initially with chloride as interlayer counter anion, have previously been shown to induce concentration and subsequent aldolization of aldehyde phosphates to form tetrose, pentose, and hexose phosphates. The reversible uptake of the simple aldehydes formaldehyde, glycolaldehyde, and glyceraldehyde by adduct formation with the immobilized sulfite ions is characterized by equilibrium constants of K=1.5, 9, and 11, respectively. This translates into an observable uptake at concentrations exceeding 50 mM.

  2. Effects of Oxygen-Containing Functional Groups on Supercapacitor Performance

    SciTech Connect

    Kerisit, Sebastien N.; Schwenzer, Birgit; Vijayakumar, M.

    2014-07-03

    Molecular dynamics (MD) simulations of the interface between graphene and the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIM OTf) were carried out to gain molecular-level insights into the performance of graphene-based supercapacitors and, in particular, determine the effects of the presence of oxygen-containing defects at the graphene surface on their integral capacitance. The MD simulations predict that increasing the surface coverage of hydroxyl groups negatively affects the integral capacitance, whereas the effect of the presence of epoxy groups is much less significant. The calculated variations in capacitance are found to be directly correlated to the interfacial structure. Indeed, hydrogen bonding between hydroxyl groups and SO3 anion moieties prevents BMIM+ and OTf- molecules from interacting favorably in the dense interfacial layer and restrains the orientation and mobility of OTf- ions, thereby reducing the permittivity of the ionic liquid at the interface. The results of the molecular simulations can facilitate the rational design of electrode materials for supercapacitors.

  3. Quantum groups and functional relations for lower rank

    NASA Astrophysics Data System (ADS)

    Nirov, Kh. S.; Razumov, A. V.

    2017-02-01

    A detailed construction of the universal integrability objects related to the integrable systems associated with the quantum loop algebra Uq(L(sl2)) is given. The full proof of the functional relations in the form independent of the representation of the quantum loop algebra on the quantum space is presented. The case of the general gradation and general twisting is treated. The specialization of the universal functional relations to the case when the quantum space is the state space of a discrete spin chain is described. This is a digression of the corresponding consideration for the case of the quantum loop algebra Uq(L(sl3)) with an extension to the higher spin case.

  4. Individual variation in hepatic aldehyde oxidase activity.

    PubMed

    Al-Salmy, H S

    2001-04-01

    Aldehyde oxidase (AO) is a molybdo-flavo enzyme expressed predominantly in the liver, lung, and kidney. AO plays a major role in oxidation of aldehydes, as well as oxidation of various N-heterocyclic compounds of pharmacological and toxicological importance including antiviral (famciclovir), antimalarial (quinine), antitumour (methotrexate), and nicotine. The aim of this study was to investigate cytosolic aldehyde oxidase activity in human liver. Cytosolic AO was characterised using both the metabolism of N-[(2-dimethylamino)ethyl] acridine-4-carboxamide (DACA) and benzaldehyde to form DACA-9(10H)-acridone (quantified by HPLC with fluorescence detection) and benzoic acid (quantified spectrophotometrically). Thirteen livers (10 female, 3 male) were examined. The intrinsic clearance (Vmax/Km) of DACA varied 18-fold (0.03-0.50 m/min/mg). Vmax ranged from 0.20-3.10 nmol/ min/mg, and Km ranged from 3.5-14.2 microM. In the same specimens, the intrinsic clearance for benzaldehyde varied 5-fold (0.40-1.8 ml/min/mg). Vmax ranged from 3.60-12.6 nmol/min/mg and Km ranged from 3.6-14.6 microM. Furthermore, there were no differences in AO activity between male and female human livers, nor was there any relationship to age of donor (range 29-73 years), smoking status, or disease status. In conclusion, our results showed that there are variations in AO activity in human liver. These variations in aldehyde oxidase activity might reflect individual variations or they might be due to AO stability during processing and storage.

  5. Synthesis of (α,α-difluoropropargyl)phosphonates via aldehyde-to-alkyne homologation.

    PubMed

    Pajkert, Romana; Röschenthaler, Gerd-Volker

    2013-04-19

    An efficient synthetic methodology to a series of novel alkynes bearing a difluoromethylenephosphonate function via a Corey-Fuchs-type sequence starting from (diethoxyphosphoryl)difluoroacetic aldehyde is described. Dehydrobromination of the intermediate (3,3-dibromodifluoroallyl)phosphonate with potassium tert-butoxide gave rise to the corresponding bromoalkyne, whereas upon treatment with lithium base, the generation of ((diethoxyphosphoryl)difluoropropynyl)lithium has been achieved for the first time. The synthetic potential of this lithium reagent was further demonstrated by its reactions with selected electrophiles such as aldehydes, ketones, triflates, chlorophosphines, and chlorosilanes, leading to the corresponding propargyl phosphonates in good to excellent yields. However, in the case, of sterically hindered aldehydes, (α-fluoroallenyl)phosphonates were the solely isolated products.

  6. Inhibitory effects of terpene alcohols and aldehydes on growth of green alga Chlorella pyrenoidosa

    SciTech Connect

    Ikawa, Miyoshi; Mosley, S.P.; Barbero, L.J. )

    1992-10-01

    The growth of the green alga Chlorella pyrenoidosa was inhibited by terpene alcohols and the terpene aldehyde citral. The strongest activity was shown by citral. Nerol, geraniol, and citronellol also showed pronounced activity. Strong inhibition was linked to acyclic terpenes containing a primary alcohol or aldehyde function. Inhibition appeared to be taking place through the vapor phase rather than by diffusion through the agar medium from the terpene-treated paper disks used in the system. Inhibition through agar diffusion was shown by certain aged samples of terpene hydrocarbons but not by recently purchased samples.

  7. Influence of substituents and functional groups on the surface composition of ionic liquids.

    PubMed

    Kolbeck, Claudia; Niedermaier, Inga; Deyko, Alexey; Lovelock, Kevin R J; Taccardi, Nicola; Wei, Wei; Wasserscheid, Peter; Maier, Florian; Steinrück, Hans-Peter

    2014-04-01

    We have performed a systematic study addressing the surface behavior of a variety of functionalized and non-functionalized ionic liquids (ILs). From angle-resolved X-ray photoelectron spectroscopy, detailed conclusions on the surface enrichment of the functional groups and the molecular orientation of the cations and anions is derived. The systems include imidazolium-based ILs methylated at the C2 position, a phenyl-functionalized IL, an alkoxysilane-functionalized IL, halo-functionalized ILs, thioether-functionalized ILs, and amine-functionalized ILs. The results are compared with the results for corresponding non-functionalized ILs where available. Generally, enrichment of the functional group at the surface is only observed for systems that have very weak interaction between the functional group and the ionic head groups.

  8. Protein reactivity of 3,4-dihydroxyphenylacetaldehyde, a toxic dopamine metabolite, is dependent on both the aldehyde and the catechol.

    PubMed

    Rees, Jennifer N; Florang, Virginia R; Eckert, Laurie L; Doorn, Jonathan A

    2009-07-01

    Dopamine (DA) has been implicated as an endogenous neurotoxin to explain selective neurodegeneration, as observed for Parkinson's disease (PD). However, previous work demonstrated that 3,4-dihydroxyphenylacetaldehyde (DOPAL) was more toxic than DA. DOPAL is generated as a part of DA catabolism via the activity of monoamine oxidase, and the mechanism of DOPAL toxicity is proposed to involve protein modification. Previous studies have demonstrated protein reactivity via the aldehyde moiety; however, DOPAL contains two reactive functional groups (catechol and aldehyde), both with the potential for protein adduction. The goal of this work was to determine whether protein modification by DOPAL occurs via a thiol-reactive quinone generated from oxidation of the catechol, which is known to occur for DA, or if the aldehyde forms adducts with amine nucleophiles. To accomplish this objective, the reactivity of DOPAL toward N-acetyl-lysine (NAL), N-acetyl-cysteine (NAC), and two model proteins was determined. In addition, several DOPAL analogues were obtained and used for comparison of reactivity. Results demonstrate that at pH 7.4 and 37 degrees C, the order of DOPAL reactivity is NAL > NAC and the product of NAL and DOPAL is stable in the absence of reducing agent. Moreover, DOPAL will react with model proteins, but in the presence of amine-selective modifiers citraconic anhydride and 2-iminothiolane hydrochloride, the reactivity of DOPAL toward the proteins is diminished. In addition, DOPAL-mediated protein cross-linking is observed when a model protein or a protein mixture (i.e., mitochondria lysate) is treated with DOPAL at concentrations of 5-100 microM. Protein cross-linking was diminished in the presence of ascorbate, suggesting the involvement of a quinone in DOPAL-mediated protein modification. These data indicate that DOPAL is highly reactive toward protein nucleophiles with the potential for protein cross-linking.

  9. Fluorescein Tri-Aldehyde Promotes the Selective Detection of Homocysteine.

    PubMed

    Barve, Aabha; Lowry, Mark; Escobedo, Jorge O; Thainashmuthu, Josephrajan; Strongin, Robert M

    2016-03-01

    Elevated homocysteine levels are a well-known independent risk factor for cardiovascular disease. To date, relatively few selective fluorescent probes for homocysteine detection have been reported. The lack of sensing reagents and remaining challenges largely derive from issues of sensitivity and/or selectivity. For example, homocysteine is a structural homologue of the more abundant (ca, 20-25 fold) aminothiol cysteine, differing only by an additional methylene group side chain. Fluorescein tri-aldehyde, described herein, has been designed and synthesized as a sensitive and selective fluorophore for the detection of homocysteine in human plasma samples. It responds to analytes selectively via a photoinduced electron transfer (PET) inhibition process that is modulated by predictable analyte-dye product hybridization and ionization states. Mulliken population analysis of fluorescein tri-aldehyde and its reaction products reveals that the characteristic formation of multiple cationic of homocysteine-derived heterocycles leads to enhanced relative negative charge build up on the proximal phenolate oxygen of the fluorophore as a contributing factor to selective emission enhancement.

  10. Quantitative evaluation of interaction force between functional groups in protein and polymer brush surfaces.

    PubMed

    Sakata, Sho; Inoue, Yuuki; Ishihara, Kazuhiko

    2014-03-18

    To understand interactions between polymer surfaces and different functional groups in proteins, interaction forces were quantitatively evaluated by force-versus-distance curve measurements using atomic force microscopy with a functional-group-functionalized cantilever. Various polymer brush surfaces were systematically prepared by surface-initiated atom transfer radical polymerization as well-defined model surfaces to understand protein adsorption behavior. The polymer brush layers consisted of phosphorylcholine groups (zwitterionic/hydrophilic), trimethylammonium groups (cationic/hydrophilic), sulfonate groups (anionic/hydrophilic), hydroxyl groups (nonionic/hydrophilic), and n-butyl groups (nonionic/hydrophobic) in their side chains. The interaction forces between these polymer brush surfaces and different functional groups (carboxyl groups, amino groups, and methyl groups, which are typical functional groups existing in proteins) were quantitatively evaluated by force-versus-distance curve measurements using atomic force microscopy with a functional-group-functionalized cantilever. Furthermore, the amount of adsorbed protein on the polymer brush surfaces was quantified by surface plasmon resonance using albumin with a negative net charge and lysozyme with a positive net charge under physiological conditions. The amount of proteins adsorbed on the polymer brush surfaces corresponded to the interaction forces generated between the functional groups on the cantilever and the polymer brush surfaces. The weakest interaction force and least amount of protein adsorbed were observed in the case of the polymer brush surface with phosphorylcholine groups in the side chain. On the other hand, positive and negative surfaces generated strong forces against the oppositely charged functional groups. In addition, they showed significant adsorption with albumin and lysozyme, respectively. These results indicated that the interaction force at the functional group level might be

  11. Toxic Diatom Aldehydes Affect Defence Gene Networks in Sea Urchins

    PubMed Central

    Varrella, Stefano; Ruocco, Nadia; Ianora, Adrianna; Bentley, Matt G.; Costantini, Maria

    2016-01-01

    Marine organisms possess a series of cellular strategies to counteract the negative effects of toxic compounds, including the massive reorganization of gene expression networks. Here we report the modulated dose-dependent response of activated genes by diatom polyunsaturated aldehydes (PUAs) in the sea urchin Paracentrotus lividus. PUAs are secondary metabolites deriving from the oxidation of fatty acids, inducing deleterious effects on the reproduction and development of planktonic and benthic organisms that feed on these unicellular algae and with anti-cancer activity. Our previous results showed that PUAs target several genes, implicated in different functional processes in this sea urchin. Using interactomic Ingenuity Pathway Analysis we now show that the genes targeted by PUAs are correlated with four HUB genes, NF-κB, p53, δ-2-catenin and HIF1A, which have not been previously reported for P. lividus. We propose a working model describing hypothetical pathways potentially involved in toxic aldehyde stress response in sea urchins. This represents the first report on gene networks affected by PUAs, opening new perspectives in understanding the cellular mechanisms underlying the response of benthic organisms to diatom exposure. PMID:26914213

  12. Daidzin: a potent, selective inhibitor of human mitochondrial aldehyde dehydrogenase.

    PubMed

    Keung, W M; Vallee, B L

    1993-02-15

    Human mitochondrial aldehyde dehydrogenase (ALDH-I) is potently, reversibly, and selectively inhibited by an isoflavone isolated from Radix puerariae and identified as daidzin, the 7-glucoside of 4',7-dihydroxyisoflavone. Kinetic analysis with formaldehyde as substrate reveals that daidzin inhibits ALDH-I competitively with respect to formaldehyde with a Ki of 40 nM, and uncompetitively with respect to the coenzyme NAD+. The human cytosolic aldehyde dehydrogenase isozyme (ALDH-II) is nearly 3 orders of magnitude less sensitive to daidzin inhibition. Daidzin does not inhibit human class I, II, or III alcohol dehydrogenases, nor does it have any significant effect on biological systems that are known to be affected by other isoflavones. Among more than 40 structurally related compounds surveyed, 12 inhibit ALDH-I, but only prunetin and 5-hydroxydaidzin (genistin) combine high selectivity and potency, although they are 7- to 15-fold less potent than daidzin. Structure-function relationships have established a basis for the design and synthesis of additional ALDH inhibitors that could both be yet more potent and specific.

  13. Palladium-catalyzed synthesis of functionalized tetraarylphosphonium salts.

    PubMed

    Marcoux, David; Charette, André B

    2008-01-18

    An efficient method to synthesize functionalized tetraarylphosphonium salts is described. This palladium-catalyzed coupling reaction between aryl iodides, bromides, or triflates and triphenylphosphine generates phosphonium salts in high yields. The coupling is compatible with a variety of functional groups such as alcohols, ketones, aldehydes, phenols, and amides.

  14. On the history of basic fuchsin and aldehyde-Schiff reactions from 1862 to 1935.

    PubMed

    Puchtler, H; Meloan, S N; Brewton, B R

    1975-01-01

    The nature of products formed by aldehydes and Schiff's reagent, whether they are sulfonic or sulfinic acid compounds, has been the subject of much discussion. It seems therefore timely to review early studies of aldehyde-Schiff reactions, including the history of pararosanilin and related dyes. Dyes of the basic fuchsin group have been studied extensively since 1862, and their triphenylmethane structure was established in 1878. The currently used structural formulas were introduced around the turn of the century. Reactions of basic fuchsin with aldehydes, with and without addition of SO2, were investigated by Schiff in the 1860's i.e. before the structure of these dyes was known. In 1900 Prud'homme showed that the reaction products of basic fuschsin, sodium bisulfite and formaldehyde are alkylated and sulfonated derivatives of the parent compound; further chemical studies indicated attachment of the sulfonic acid group to the carbon atom of the aldehyde. Prud'homme's findings were repeatedly confirmed during the following decades. Wieland and Scheuing were apparently unaware of these studies and introduced the sulfinic acid theory in 1921; furthermore, they considered substitution at two amino group of Schiff's reagent essential for formation of the colored compound. However, later chemical and spectroscopic studies showed no evidence of-N-sulfinic acids but supported the sulfonic acid theory of Prud'homme.

  15. Polymerization of 1,3-Dienes with Functional Groups. 4.

    NASA Astrophysics Data System (ADS)

    Takenaka, Katsuhiko; Shibata, Natsuyo; Tsuchida, Shinsuke; Takeshita, Hiroki; Miya, Masamitsu; Shiomi, Tomoo

    Anionic polymerization of N,N-diethyl-2-methylene-3-butenamide (DEA), which is a 1,3-butadiene derivative containing a diethylamide function, was carried out in tetrahydrofurane (THF) under various conditions. When DEA was polymerized in THF at -78°C using potassium naphthalenide (K-Naph) or diphenylmethylpotassium (DPMK) as an initiator, a polymer of predictable molecular weight with a narrow molecular weight distribution was obtained. However, the rate of polymerization was extremely slow to reach 80% conversion after 720 h. When the polymerization temperature was raised to 20°C, a low molecular weight oligomer with a broad molecular weight distribution was obtained because of a chain transfer reaction. On the other hand, no such side reaction occurred even at 20°C, when polymerization was carried out in the presence of LiCl. Also, the chain transfer reaction did not occur in lithium naphthalenide (Li-Naph) initiated polymerization. The microstructure of the polymer prepared using a potassium counter cation was a 1 : 1 mixture of 1,4-E and 1,2- structures. In the case of Li-Naph or DPMK/LiCl systems, the microstructure was a complicated mixture of 1,4-E, 1,4-Z, and 1,2-structures.

  16. Critical effect of dependency groups on the function of networks.

    PubMed

    Parshani, Roni; Buldyrev, Sergey V; Havlin, Shlomo

    2011-01-18

    Current network models assume one type of links to define the relations between the network entities. However, many real networks can only be correctly described using two different types of relations. Connectivity links that enable the nodes to function cooperatively as a network and dependency links that bind the failure of one network element to the failure of other network elements. Here we present an analytical framework for studying the robustness of networks that include both connectivity and dependency links. We show that a synergy exists between the failure of connectivity and dependency links that leads to an iterative process of cascading failures that has a devastating effect on the network stability. We present exact analytical results for the dramatic change in the network behavior when introducing dependency links. For a high density of dependency links, the network disintegrates in a form of a first-order phase transition, whereas for a low density of dependency links, the network disintegrates in a second-order transition. Moreover, opposed to networks containing only connectivity links where a broader degree distribution results in a more robust network, when both types of links are present a broad degree distribution leads to higher vulnerability.

  17. Critical effect of dependency groups on the function of networks

    PubMed Central

    Parshani, Roni; Buldyrev, Sergey V.; Havlin, Shlomo

    2011-01-01

    Current network models assume one type of links to define the relations between the network entities. However, many real networks can only be correctly described using two different types of relations. Connectivity links that enable the nodes to function cooperatively as a network and dependency links that bind the failure of one network element to the failure of other network elements. Here we present an analytical framework for studying the robustness of networks that include both connectivity and dependency links. We show that a synergy exists between the failure of connectivity and dependency links that leads to an iterative process of cascading failures that has a devastating effect on the network stability. We present exact analytical results for the dramatic change in the network behavior when introducing dependency links. For a high density of dependency links, the network disintegrates in a form of a first-order phase transition, whereas for a low density of dependency links, the network disintegrates in a second-order transition. Moreover, opposed to networks containing only connectivity links where a broader degree distribution results in a more robust network, when both types of links are present a broad degree distribution leads to higher vulnerability. PMID:21191103

  18. METALLICITY DISTRIBUTION FUNCTIONS OF FOUR LOCAL GROUP DWARF GALAXIES

    SciTech Connect

    Ross, Teresa L.; Holtzman, Jon; Saha, Abhijit; Anthony-Twarog, Barbara J. E-mail: holtz@nmsu.edu

    2015-06-15

    We present stellar metallicities in Leo I, Leo II, IC 1613, and Phoenix dwarf galaxies derived from medium (F390M) and broad (F555W, F814W) band photometry using the Wide Field Camera 3 instrument on board the Hubble Space Telescope. We measured metallicity distribution functions (MDFs) in two ways, (1) matching stars to isochrones in color–color diagrams and (2) solving for the best linear combination of synthetic populations to match the observed color–color diagram. The synthetic technique reduces the effect of photometric scatter and produces MDFs 30%–50% narrower than the MDFs produced from individually matched stars. We fit the synthetic and individual MDFs to analytical chemical evolution models (CEMs) to quantify the enrichment and the effect of gas flows within the galaxies. Additionally, we measure stellar metallicity gradients in Leo I and II. For IC 1613 and Phoenix our data do not have the radial extent to confirm a metallicity gradient for either galaxy. We find the MDF of Leo I (dwarf spheroidal) to be very peaked with a steep metal-rich cutoff and an extended metal-poor tail, while Leo II (dwarf spheroidal), Phoenix (dwarf transition), and IC 1613 (dwarf irregular) have wider, less peaked MDFs than Leo I. A simple CEM is not the best fit for any of our galaxies; therefore we also fit the “Best Accretion Model” of Lynden-Bell. For Leo II, IC 1613, and Phoenix we find similar accretion parameters for the CEM even though they all have different effective yields, masses, star formation histories, and morphologies. We suggest that the dynamical history of a galaxy is reflected in the MDF, where broad MDFs are seen in galaxies that have chemically evolved in relative isolation and narrowly peaked MDFs are seen in galaxies that have experienced more complicated dynamical interactions concurrent with their chemical evolution.

  19. Red electroluminescence of ruthenium sensitizer functionalized by sulfonate anchoring groups.

    PubMed

    Shahroosvand, Hashem; Abbasi, Parisa; Mohajerani, Ezeddin; Janghouri, Mohammad

    2014-06-28

    We have synthesized five novel Ru(ii) phenanthroline complexes with an additional aryl sulfonate ligating substituent at the 5-position [Ru(L)(bpy)2](BF4)2 (1), [Ru(L)(bpy)(SCN)2] (2), [Ru(L)3](BF4)2 (3), [Ru(L)2(bpy)](BF4)2 (4) and [Ru(L)(BPhen)(SCN)2] (5) (where L = 6-one-[1,10]phenanthroline-5-ylamino)-3-hydroxynaphthalene 1-sulfonic, bpy = 2,2'-bipyridine, BPhen = 4,7-diphenyl-1,10-phenanthroline), as both photosensitizers for oxide semiconductor solar cells (DSSCs) and light emitting diodes (LEDs). The absorption and emission maxima of these complexes red shifted upon extending the conjugation of the phenanthroline ligand. Ru phenanthroline complexes exhibit broad metal to ligand charge transfer-centered electroluminescence (EL) with a maximum near 580 nm. Our results indicated that a particular structure (2) can be considered as both DSSC and OLED devices. The efficiency of the LED performance can be tuned by using a range of ligands. Device (2) has a luminance of 550 cd m(-2) and maximum efficiency of 0.9 cd A(-1) at 18 V, which are the highest values among the five devices. The turn-on voltage of this device is approximately 5 V. The role of auxiliary ligands in the photophysical properties of Ru complexes was investigated by DFT calculation. We have also studied photovoltaic properties of dye-sensitized nanocrystalline semiconductor solar cells based on Ru phenanthroline complexes and an iodine redox electrolyte. A solar energy to electricity conversion efficiency (η) of 0.67% was obtained for Ru complex (2) under standard AM 1.5 irradiation with a short-circuit photocurrent density (Jsc) of 2.46 mA cm(-2), an open-circuit photovoltage (Voc) of 0.6 V, and a fill factor (ff) of 40%, which are all among the highest values for ruthenium sulfonated anchoring groups reported so far. Monochromatic incident photon to current conversion efficiency was 23% at 475 nm. Photovoltaic studies clearly indicated dyes with two SCN substituents yielded a higher Jsc for the

  20. Metallicity Distribution Functions of Four Local Group Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Ross, Teresa L.; Holtzman, Jon; Saha, Abhijit; Anthony-Twarog, Barbara J.

    2015-06-01

    We present stellar metallicities in Leo I, Leo II, IC 1613, and Phoenix dwarf galaxies derived from medium (F390M) and broad (F555W, F814W) band photometry using the Wide Field Camera 3 instrument on board the Hubble Space Telescope. We measured metallicity distribution functions (MDFs) in two ways, (1) matching stars to isochrones in color-color diagrams and (2) solving for the best linear combination of synthetic populations to match the observed color-color diagram. The synthetic technique reduces the effect of photometric scatter and produces MDFs 30%-50% narrower than the MDFs produced from individually matched stars. We fit the synthetic and individual MDFs to analytical chemical evolution models (CEMs) to quantify the enrichment and the effect of gas flows within the galaxies. Additionally, we measure stellar metallicity gradients in Leo I and II. For IC 1613 and Phoenix our data do not have the radial extent to confirm a metallicity gradient for either galaxy. We find the MDF of Leo I (dwarf spheroidal) to be very peaked with a steep metal-rich cutoff and an extended metal-poor tail, while Leo II (dwarf spheroidal), Phoenix (dwarf transition), and IC 1613 (dwarf irregular) have wider, less peaked MDFs than Leo I. A simple CEM is not the best fit for any of our galaxies; therefore we also fit the “Best Accretion Model” of Lynden-Bell. For Leo II, IC 1613, and Phoenix we find similar accretion parameters for the CEM even though they all have different effective yields, masses, star formation histories, and morphologies. We suggest that the dynamical history of a galaxy is reflected in the MDF, where broad MDFs are seen in galaxies that have chemically evolved in relative isolation and narrowly peaked MDFs are seen in galaxies that have experienced more complicated dynamical interactions concurrent with their chemical evolution. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is

  1. Aldehyde Oxidase 4 Plays a Critical Role in Delaying Silique Senescence by Catalyzing Aldehyde Detoxification1[OPEN

    PubMed Central

    Yarmolinsky, Dmitry; Soltabayeva, Aigerim; Samani, Talya

    2017-01-01

    The Arabidopsis (Arabidopsis thaliana) aldehyde oxidases are a multigene family of four oxidases (AAO1–AAO4) that oxidize a variety of aldehydes, among them abscisic aldehyde, which is oxidized to the phytohormone abscisic acid. Toxic aldehydes are generated in plants both under normal conditions and in response to stress. The detoxification of such aldehydes by oxidation is attributed to aldehyde dehydrogenases but never to aldehyde oxidases. The feasibility of the detoxification of aldehydes in siliques via oxidation by AAO4 was demonstrated, first, by its ability to efficiently oxidize an array of aromatic and aliphatic aldehydes, including the reactive carbonyl species (RCS) acrolein, hydroxyl-2-nonenal, and malondialdehyde. Next, exogenous application of several aldehydes to siliques in AAO4 knockout (KO) Arabidopsis plants induced severe tissue damage and enhanced malondialdehyde levels and senescence symptoms, but not in wild-type siliques. Furthermore, abiotic stresses such as dark and ultraviolet C irradiation caused an increase in endogenous RCS and higher expression levels of senescence marker genes, leading to premature senescence of KO siliques, whereas RCS and senescence marker levels in wild-type siliques were hardly affected. Finally, in naturally senesced KO siliques, higher endogenous RCS levels were associated with enhanced senescence molecular markers, chlorophyll degradation, and earlier seed shattering compared with the wild type. The aldehyde-dependent differential generation of superoxide and hydrogen peroxide by AAO4 and the induction of AAO4 expression by hydrogen peroxide shown here suggest a self-amplification mechanism for detoxifying additional reactive aldehydes produced during stress. Taken together, our results indicate that AAO4 plays a critical role in delaying senescence in siliques by catalyzing aldehyde detoxification. PMID:28188272

  2. Occupational Exposure to Volatile Organic Compounds and Aldehydes in the U.S. Trucking Industry

    PubMed Central

    DAVIS, M. E.; BLICHARZ, A. P.; HART, J. E.; LADEN, F.; GARSHICK, E.; SMITH, T. J.

    2008-01-01

    Diesel exhaust is a complex chemical mixture that has been linked to lung cancer mortality in a number of epidemiologic studies. However, the dose–response relationship remains largely undefined, and the specific components responsible for carcinogenicity have not been identified. Although previous focus has been on the particulate phase, diesel exhaust includes a vapor phase of numerous volatile organic compounds (VOCs) and aldehydes that are either known or suspected carcinogens, such as 1,3-butadiene, benzene, and formaldehyde. However, there are relatively few studies that quantify exposure to VOCs and aldehydes in diesel-heavy and other exhaust-related microenvironments. As part of a nationwide assessment of exposure to diesel exhaust in the trucking industry, we collected measurements of VOCs and aldehydes at 15 different U.S. trucking terminals and in city truck drivers (with 6 repeat site visits), observing average shift concentrations in truck cabs and at multiple background and work area locations within each terminal. In this paper, we characterize occupational exposure to 18 different VOCs and aldehydes, as well as relationships with particulate mass (elemental carbon in PM < 1 μ m and PM2.5) across locations to determine source characteristics. Our results show that occupational exposure to VOCs and aldehydes varies significantly across the different sampling locations within each terminal, with significantly higher exposures noted in the work environments over background levels (p < 0.01). A structural equation model performed well in predicting terminal exposures to VOCs and aldehydes as a function of job, background levels, weather conditions, proximity to a major road, and geographic location (R2 = 0.2–0.4 work area; R2 = 0.5–0.9 background). PMID:17993162

  3. Soft and Bio Nanomaterials Group at Brookhaven’s Center for Functional Nanomaterials

    SciTech Connect

    Gang, Oleg

    2016-12-07

    Group leader Oleg Gang talks about the methods his group develops to direct the self-assembly of nanoscale systems from organic and inorganic components into functional materials with desired properties.

  4. Soft and Bio Nanomaterials Group at Brookhaven’s Center for Functional Nanomaterials

    ScienceCinema

    Gang, Oleg

    2016-12-14

    Group leader Oleg Gang talks about the methods his group develops to direct the self-assembly of nanoscale systems from organic and inorganic components into functional materials with desired properties.

  5. Tunable Oxygen Functional Groups as Electrocatalysts on Graphite Felt Surfaces for All-Vanadium Flow Batteries

    SciTech Connect

    Estevez, Luis; Reed, David; Nie, Zimin; Schwarz, Ashleigh M.; Nandasiri, Manjula I.; Kizewski, James P.; Wang, Wei; Thomsen, Edwin; Liu, Jun; Zhang, Ji-Guang; Sprenkle, Vincent; Li, Bin

    2016-05-17

    We decorated the surfaces of graphite felts with some oxygen-containing functional groups, such as C-OH, O=C and HO-C=O. And the mole ratios and amounts of these functional groups were effectively adjusted on the graphite surface by a particular method. The catalytic effects of amounts and mole ratio of different kinds of functional groups on VRB electrode performances were investigated in detail.

  6. Mechanism of aldehyde oxidation catalyzed by horse liver alcohol dehydrogenase.

    PubMed

    Olson, L P; Luo, J; Almarsson, O; Bruice, T C

    1996-07-30

    The mechanism of oxidation of benzaldehyde to benzoic acid catalyzed by horse liver alcohol dehydrogenase (HLADH) has been investigated using the HLADH structure at 2.1 A resolution with NAD+ and pentafluorobenzyl alcohol in the active site [Ramaswamy et al. (1994) Biochemistry 33,5230-5237]. Constructs for molecular dynamics (MD) investigations with HLADH were obtained by a best-fit superimposition of benzaldehyde or its hydrate on the pentafluorobenzyl alcohol bound to the active site Zn(II)ion. Equilibrium bond lengths, angles, and dihedral parameters for Zn(II) bonding residues His67, Cys46, and Cys174 were obtained from small-molecule X-ray crystal structures and an ab initio-derived parameterization of zinc in HLADH [Ryde, U. (1995) Proteins: Struct., Funct., Genet. 21,40-56]. Dynamic simulations in CHARMM were carried out on the following three constructs to 100 ps: (MD1) enzyme with NAD+, benzaldehyde, and zinc-ligated HO-in the active site; (MD2) enzyme with NAD+ and hydrated benzaldehyde monoanion bound to zinc via the pro-R oxygen, with a proton residing on the pro-S oxygen; and (MD3) enzyme with NAD+ and hydrated benzaldehyde monoanion bound to zinc via the pro-S oxygen, with a proton residing on the pro-R oxygen. Analyses were done of 800 sample conformations taken in the last 40 ps of dynamics. Structures from MD1 and MD3 were used to define the initial spatial arrangements of reactive functionalities for semiempirical PM3 calculations. Using PM3, model systems were calculated of ground states and some transition states for aldehyde hydration, hydride transfer, and subsequent proton shuttling. With benzaldehyde and zinc-bound hydroxide ion in the active site, the oxygen of Zn(II)-OH resided at a distance of 2.8-5.5 A from the aldehyde carbonyl carbon during the dynamics simulation. This may be compared to the PM3 transition state for attack of the Zn(II)-OH oxygen on the benzaldehyde carbonyl carbon, which has an O...C distance of 1.877 A. HLADH

  7. Kinetics of Forming Aldehydes in Frying Oils and Their Distribution in French Fries Revealed by LC-MS-Based Chemometrics.

    PubMed

    Wang, Lei; Csallany, A Saari; Kerr, Brian J; Shurson, Gerald C; Chen, Chi

    2016-05-18

    In this study, the kinetics of aldehyde formation in heated frying oils was characterized by 2-hydrazinoquinoline derivatization, liquid chromatography-mass spectrometry (LC-MS) analysis, principal component analysis (PCA), and hierarchical cluster analysis (HCA). The aldehydes contributing to time-dependent separation of heated soybean oil (HSO) in a PCA model were grouped by the HCA into three clusters (A1, A2, and B) on the basis of their kinetics and fatty acid precursors. The increases of 4-hydroxynonenal (4-HNE) and the A2-to-B ratio in HSO were well-correlated with the duration of thermal stress. Chemometric and quantitative analysis of three frying oils (soybean, corn, and canola oils) and French fry extracts further supported the associations between aldehyde profiles and fatty acid precursors and also revealed that the concentrations of pentanal, hexanal, acrolein, and the A2-to-B ratio in French fry extracts were more comparable to their values in the frying oils than other unsaturated aldehydes. All of these results suggest the roles of specific aldehydes or aldehyde clusters as novel markers of the lipid oxidation status for frying oils or fried foods.

  8. A coniferyl aldehyde dehydrogenase gene from Pseudomonas sp. strain HR199 enhances the conversion of coniferyl aldehyde by Saccharomyces cerevisiae.

    PubMed

    Adeboye, Peter Temitope; Olsson, Lisbeth; Bettiga, Maurizio

    2016-07-01

    The conversion of coniferyl aldehyde to cinnamic acids by Saccharomyces cerevisiae under aerobic growth conditions was previously observed. Bacteria such as Pseudomonas have been shown to harbor specialized enzymes for converting coniferyl aldehyde but no comparable enzymes have been identified in S. cerevisiae. CALDH from Pseudomonas was expressed in S. cerevisiae. An acetaldehyde dehydrogenase (Ald5) was also hypothesized to be actively involved in the conversion of coniferyl aldehyde under aerobic growth conditions in S. cerevisiae. In a second S. cerevisiae strain, the acetaldehyde dehydrogenase (ALD5) was deleted. A prototrophic control strain was also engineered. The engineered S. cerevisiae strains were cultivated in the presence of 1.1mM coniferyl aldehyde under aerobic condition in bioreactors. The results confirmed that expression of CALDH increased endogenous conversion of coniferyl aldehyde in S. cerevisiae and ALD5 is actively involved with the conversion of coniferyl aldehyde in S. cerevisiae.

  9. Electron impact ionization of cycloalkanes, aldehydes, and ketones

    SciTech Connect

    Gupta, Dhanoj; Antony, Bobby

    2014-08-07

    The theoretical calculations of electron impact total ionization cross section for cycloalkane, aldehyde, and ketone group molecules are undertaken from ionization threshold to 2 keV. The present calculations are based on the spherical complex optical potential formalism and complex scattering potential ionization contribution method. The results of most of the targets studied compare fairly well with the recent measurements, wherever available and the cross sections for many targets are predicted for the first time. The correlation between the peak of ionization cross sections with number of target electrons and target parameters is also reported. It was found that the cross sections at their maximum depend linearly with the number of target electrons and with other target parameters, confirming the consistency of the values reported here.

  10. Asymmetric intramolecular α-cyclopropanation of aldehydes using a donor/acceptor carbene mimetic

    PubMed Central

    Luo, Chaosheng; Wang, Zhen; Huang, Yong

    2015-01-01

    Enantioselective α-alkylation of carbonyl is considered as one of the most important processes for asymmetric synthesis. Common alkylation agents, that is, alkyl halides, are notorious substrates for both Lewis acids and organocatalysts. Recently, olefins emerged as a benign alkylating species via photo/radical mechanisms. However, examples of enantioselective alkylation of aldehydes/ketones are scarce and direct asymmetric dialkylation remains elusive. Here we report an intramolecular α-cyclopropanation reaction of olefinic aldehydes to form chiral cyclopropane aldehydes. We demonstrate that an α-iodo aldehyde can function as a donor/acceptor carbene equivalent, which engages in a formal [2+1] annulation with a tethered double bond. Privileged bicyclo[3.1.0]hexane-type scaffolds are prepared in good optical purity using a chiral amine. The synthetic utility of the products is demonstrated by versatile transformations of the bridgehead formyl functionality. We expect the concept of using α-iodo iminium as a donor/acceptor carbene surrogate will find wide applications in chemical reaction development. PMID:26644194

  11. A CRM domain protein functions dually in group I and group II intron splicing in land plant chloroplasts.

    PubMed

    Asakura, Yukari; Barkan, Alice

    2007-12-01

    The CRM domain is a recently recognized RNA binding domain found in three group II intron splicing factors in chloroplasts, in a bacterial protein that associates with ribosome precursors, and in a family of uncharacterized proteins in plants. To elucidate the functional repertoire of proteins with CRM domains, we studied CFM2 (for CRM Family Member 2), which harbors four CRM domains. RNA coimmunoprecipitation assays showed that CFM2 in maize (Zea mays) chloroplasts is associated with the group I intron in pre-trnL-UAA and group II introns in the ndhA and ycf3 pre-mRNAs. T-DNA insertions in the Arabidopsis thaliana ortholog condition a defective-seed phenotype (strong allele) or chlorophyll-deficient seedlings with impaired splicing of the trnL group I intron and the ndhA, ycf3-int1, and clpP-int2 group II introns (weak alleles). CFM2 and two previously described CRM proteins are bound simultaneously to the ndhA and ycf3-int1 introns and act in a nonredundant fashion to promote their splicing. With these findings, CRM domain proteins are implicated in the activities of three classes of catalytic RNA: group I introns, group II introns, and 23S rRNA.

  12. Functional Groups Based on Leaf Physiology: Are they Spatially and Temporally Robust?

    NASA Technical Reports Server (NTRS)

    Foster, Tammy E.; Brooks, J. Renee; Quincy, Charles (Technical Monitor)

    2002-01-01

    The functional grouping hypothesis, which suggests that complexity in function can be simplified by grouping species with similar responses, was tested in the Florida scrub habitat. Functional groups were identified based on how species in fire maintained FL scrub function in terms of carbon, water and nitrogen dynamics. The suite of physiologic parameters measured to determine function included both instantaneous gas exchange measurements obtained from photosynthetic light response curves and integrated measures of function. Using cluster analysis, five distinct physiologically-based functional groups were identified. Using non-parametric multivariate analyses, it was determined that these five groupings were not altered by plot differences or by the three different management regimes; prescribed burn, mechanically treated and burn, and fire-suppressed. The physiological groupings also remained robust between the two years 1999 and 2000. In order for these groupings to be of use for scaling ecosystem processes, there needs to be an easy-to-measure morphological indicator of function. Life form classifications were able to depict the physiological groupings more adequately than either specific leaf area or leaf thickness. THe ability of life forms to depict the groupings was improved by separating the parasitic Ximenia americana from the shrub category.

  13. Building functional groups of marine benthic macroinvertebrates on the basis of general community assembly mechanisms

    NASA Astrophysics Data System (ADS)

    Alexandridis, Nikolaos; Bacher, Cédric; Desroy, Nicolas; Jean, Fred

    2017-03-01

    The accurate reproduction of the spatial and temporal dynamics of marine benthic biodiversity requires the development of mechanistic models, based on the processes that shape macroinvertebrate communities. The modelled entities should, accordingly, be able to adequately represent the many functional roles that are performed by benthic organisms. With this goal in mind, we applied the emergent group hypothesis (EGH), which assumes functional equivalence within and functional divergence between groups of species. The first step of the grouping involved the selection of 14 biological traits that describe the role of benthic macroinvertebrates in 7 important community assembly mechanisms. A matrix of trait values for the 240 species that occurred in the Rance estuary (Brittany, France) in 1995 formed the basis for a hierarchical classification that generated 20 functional groups, each with its own trait values. The functional groups were first evaluated based on their ability to represent observed patterns of biodiversity. The two main assumptions of the EGH were then tested, by assessing the preservation of niche attributes among the groups and the neutrality of functional differences within them. The generally positive results give us confidence in the ability of the grouping to recreate functional diversity in the Rance estuary. A first look at the emergent groups provides insights into the potential role of community assembly mechanisms in shaping biodiversity patterns. Our next steps include the derivation of general rules of interaction and their incorporation, along with the functional groups, into mechanistic models of benthic biodiversity.

  14. A comparative study of six different inpatient groups with respect to their basic assumption functioning.

    PubMed

    Karterud, S

    1989-07-01

    Seventy-five group therapy sessions of six different inpatient team groups in one short-term, one intermediate term, and one long-term psychiatric ward were studied with Group Focal Conflict Analysis and the Group Emotionality Rating System. The majority of the group sessions (41) functioned as fight-flight groups, twenty-four sessions functioned at a "pseudogroup" level, and ten sessions were dependency groups. The differences between the fight-flight groups and the dependency group on the variables aggression and dependency were highly significant statistically. A mixture of fight-flight groups and pseudogroups were found in the short-term ward with emergency obligations. The author discusses the assets and shortcomings of fight-flight and dependency cultures within psychiatric wards.

  15. [Response of Phytoplankton Functional Groups to Eutrophication in Summer at Xiaoguan Reservoir].

    PubMed

    Li, Lei; Li, Qiu-hua; Jiao, Shu-lin; Li, Yue; Xiao, Jing; Deng, Long; Sun, Rong-guo; Gao, Yong-chun; Luo, Lan

    2015-12-01

    Hydrology and Water Resources Bureau of Guizhou Province, Guiyang 550002, China) Abstract: In order to explore the distribution characteristics of phytoplankton functional groups, eutrophication characteristics and response of phytoplankton functional groups to eutrophication in Xiaoguan Reservoir, phytoplankton and water samples were taken once a week from 25th July 2014 to 27th September 2014. The results showed that there were 22 phytoplankton functional groups, groups S1, D, J, B, G, MP, L₀, SN, X1, Y, Xph, F, T and W1 were comparatively common functional groups, Wherein, S1, D and J were the dominant functional groups. Weekly dynamics of phytoplankton functional groups were: S1-->S1-->S1-->S1-->S1--S1-->S1-->J/D/S1-->Sl1- >/1D. group Sl1dominated over other groups, the cell abundance of S1 appeared two peaks at week 5 and week 7 respectively, but there was a slump at week 8, and rose again at last, compared to two peaks before, the cell abundance had dropped from 10⁸cells · L⁻¹ to 10⁷cells · L⁻¹ Water flush caused by discharge gate opening artificially was the main reason. Based on the three methods of eutrophication evaluation, the water was in moderately eutrophic and eutrophic states in Xiaoguan Reservoir in the summer of 2014. Multivariate analysis (RDA) indicated transparency was the main factor affecting the distribution of phytoplankton functional groups, and nutrients were no longer the limiting factor. The study suggested that phytoplankton functional groups could make a good response to eutrophication: groups S1 and J adapted to the turbid eutrophic water bodies, D adapted to shallow turbid waters and was sensitive to nutrient depletion. Also, common functional groups like G, X1, WW1 F etc. mostly adapted to eutrophic water bodies.

  16. Structure and function studies on enzymes with a catalytic carboxyl group(s): from ribonuclease T1 to carboxyl peptidases

    PubMed Central

    TAKAHASHI, Kenji

    2013-01-01

    A group of enzymes, mostly hydrolases or certain transferases, utilize one or a few side-chain carboxyl groups of Asp and/or Glu as part of the catalytic machinery at their active sites. This review follows mainly the trail of studies performed by the author and his colleagues on the structure and function of such enzymes, starting from ribonuclease T1, then extending to three major types of carboxyl peptidases including aspartic peptidases, glutamic peptidases and serine-carboxyl peptidases. PMID:23759941

  17. Targeting Aldehyde Dehydrogenase 2: New Therapeutic Opportunities

    PubMed Central

    Chen, Che-Hong; Ferreira, Julio Cesar Batista; Gross, Eric R.; Mochly-Rosen, Daria

    2014-01-01

    A family of detoxifying enzymes called aldehyde dehydrogenases (ALDHs) has been a subject of recent interest, as its role in detoxifying aldehydes that accumulate through metabolism and to which we are exposed from the environment has been elucidated. Although the human genome has 19 ALDH genes, one ALDH emerges as a particularly important enzyme in a variety of human pathologies. This ALDH, ALDH2, is located in the mitochondrial matrix with much known about its role in ethanol metabolism. Less known is a new body of research to be discussed in this review, suggesting that ALDH2 dysfunction may contribute to a variety of human diseases including cardiovascular diseases, diabetes, neurodegenerative diseases, stroke, and cancer. Recent studies suggest that ALDH2 dysfunction is also associated with Fanconi anemia, pain, osteoporosis, and the process of aging. Furthermore, an ALDH2 inactivating mutation (termed ALDH2*2) is the most common single point mutation in humans, and epidemiological studies suggest a correlation between this inactivating mutation and increased propensity for common human pathologies. These data together with studies in animal models and the use of new pharmacological tools that activate ALDH2 depict a new picture related to ALDH2 as a critical health-promoting enzyme. PMID:24382882

  18. OLFACTORY RESPONSES OF BLOWFLIES TO ALIPHATIC ALDEHYDES

    PubMed Central

    Dethier, V. G.

    1954-01-01

    The response of the blowfly Phormia regina to stimulation by aldehydes in the vapor phase has been studied by means of a specially designed olfactometer. The median rejection threshold and the maximum acceptance threshold were selected as criteria of response. For both acceptance and rejection the distribution of thresholds in the population is normal with respect to the logarithm of concentration. When thresholds are expressed as molar concentrations, the values decrease progressively as chain length is increased. There is no attraction beyond decanal and no rejection beyond dodecanal. When thresholds are expressed as activities, most members of the aldehyde series are approximately equally stimulating at rejection and equally stimulating at acceptance. The relationship is most exact over the middle range of chain lengths. There is a tendency for the terminal members to stimulate at higher activities. These relationships are in close agreement with those which were found earlier to apply to the normal aliphatic alcohols. The similarity between the relative actions of the members of the two series suggests that the relation of equal olfactory stimulation at equal thermodynamic activities by homologous aliphatic compounds at least for homologues of intermediate chain length may be of rather general application in olfaction. PMID:13174780

  19. Studies on organic indole-3-aldehyde single crystals

    NASA Astrophysics Data System (ADS)

    Haja Hameed, A. S.; Ravi, G.; Dhanasekaran, R.; Ramasamy, P.

    Indole-3-aldehyde (IA) is a new organic nonlinear material for which its solubility in methanol and acetone was found out using the apparatus fabricated by the authors. In order to get the good-quality crystals, methods of evaporation of solvent at room temperature and slow cooling of saturated solution at boiling temperature were adopted. Simulated lattice parameter values were found out using experimentally known " d" values. The etching and mechanical strength studies on different planes of the crystal were carried out. Decomposition temperature, weight loss and different functional bond frequencies associated with the crystal were also found out from differential thermal analysis (DTA), thermo-gravimetric analysis (TGA) and Fourier transform infra-red (FTIR) spectroscopic analysis, respectively.

  20. Macroevolutionary trends of atomic composition and related functional group proportion in eukaryotic and prokaryotic proteins.

    PubMed

    Zhang, Yu-Juan; Yang, Chun-Lin; Hao, You-Jin; Li, Ying; Chen, Bin; Wen, Jian-Fan

    2014-01-25

    To fully explore the trends of atomic composition during the macroevolution from prokaryote to eukaryote, five atoms (oxygen, sulfur, nitrogen, carbon, hydrogen) and related functional groups in prokaryotic and eukaryotic proteins were surveyed and compared. Genome-wide analysis showed that eukaryotic proteins have more oxygen, sulfur and nitrogen atoms than prokaryotes do. Clusters of Orthologous Groups (COG) analysis revealed that oxygen, sulfur, carbon and hydrogen frequencies are higher in eukaryotic proteins than in their prokaryotic orthologs. Furthermore, functional group analysis demonstrated that eukaryotic proteins tend to have higher proportions of sulfhydryl, hydroxyl and acylamino, but lower of sulfide and carboxyl. Taken together, an apparent trend of increase was observed for oxygen and sulfur atoms in the macroevolution; the variation of oxygen and sulfur compositions and their related functional groups in macroevolution made eukaryotic proteins carry more useful functional groups. These results will be helpful for better understanding the functional significances of atomic composition evolution.

  1. Dual Lewis Acid/Lewis Base Catalyzed Acylcyanation of Aldehydes: A Mechanistic Study.

    PubMed

    Laurell Nash, Anna; Hertzberg, Robin; Wen, Ye-Qian; Dahlgren, Björn; Brinck, Tore; Moberg, Christina

    2016-03-07

    A mechanistic investigation, which included a Hammett correlation analysis, evaluation of the effect of variation of catalyst composition, and low-temperature NMR spectroscopy studies, of the Lewis acid-Lewis base catalyzed addition of acetyl cyanide to prochiral aldehydes provides support for a reaction route that involves Lewis base activation of the acyl cyanide with formation of a potent acylating agent and cyanide ion. The cyanide ion adds to the carbonyl group of the Lewis acid activated aldehyde. O-Acylation by the acylated Lewis base to form the final cyanohydrin ester occurs prior to decomplexation from titanium. For less reactive aldehydes, the addition of cyanide is the rate-determining step, whereas, for more reactive, electron-deficient aldehydes, cyanide addition is rapid and reversible and is followed by rate-limiting acylation. The resting state of the catalyst lies outside the catalytic cycle and is believed to be a monomeric titanium complex with two alcoholate ligands, which only slowly converts into the product.

  2. Copper-catalyzed retro-aldol reaction of β-hydroxy ketones or nitriles with aldehydes: chemo- and stereoselective access to (E)-enones and (E)-acrylonitriles.

    PubMed

    Zhang, Song-Lin; Deng, Zhu-Qin

    2016-07-26

    A copper-catalyzed transfer aldol type reaction of β-hydroxy ketones or nitriles with aldehydes is reported, which enables chemo- and stereoselective access to (E)-α,β-unsaturated ketones and (E)-acrylonitriles. A key step of the in situ copper(i)-promoted retro-aldol reaction of β-hydroxy ketones or nitriles is proposed to generate a reactive Cu(i) enolate or cyanomethyl intermediate, which undergoes ensuing aldol condensation with aldehydes to deliver the products. This reaction uses 1.2 mol% Cu(IPr)Cl (IPr denotes 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) as the catalyst in the presence of 6.0 mol% NaOtBu cocatalyst at room temperature or 70 °C. A range of aryl and heteroaryl aldehydes as well as acrylaldehydes are compatible with many useful functional groups being tolerated. Under the mild and weakly basic conditions, competitive Cannizzaro-type reaction of benzaldehydes and side reactions of base-sensitive functional groups can be effectively suppressed, which show synthetic advantages of this reaction compared to classic aldol reactions. The synthetic potential of this reaction is further demonstrated by the one-step synthesis of biologically active quinolines and 1,8-naphthyridine in excellent yields (up to 91%). Finally, a full catalytic cycle for this reaction has been constructed using DFT computational studies in the context of a retro-aldol/aldol two-stage mechanism. A rather flat reaction energy profile is found indicating that both stages are kinetically facile, which is consistent with the mild reaction conditions.

  3. Study of both sunflower oil and its headspace throughout the oxidation process. Occurrence in the headspace of toxic oxygenated aldehydes.

    PubMed

    Guillén, María D; Cabo, Nerea; Ibargoitia, María L; Ruiz, Ainhoa

    2005-02-23

    The static headspace composition of sunflower oil throughout the oxidation process at 70 degrees C with circulating air is studied by means of solid-phase microextraction followed by gas chromatography-mass spectrometry (SPME-GC-MS); at the same time the liquid phase of the same oil is studied by means of Fourier transform infrared (FTIR) spectroscopy. Each technique provides complementary information about the process; FITR spectroscopy detects changes in the functional groups of the liquid matrix in a global way and SPME/GC-MS provides information about the different components present in the volatile phase during the oxidation process. Concordance between the timing of the changes produced in both liquid and gaseous phases is observed, as well as agreement and complementarity in the results obtained from both phases. The formation of some well-known genotoxic and cytotoxic oxygenated aldehydes in this process and their presence in the oil headspace are proved.

  4. Aldose Reductase-catalyzed Reduction of Aldehyde Phospholipids

    PubMed Central

    Srivastava, Sanjay; Spite, Matthew; Trent, John O.; West, Matthew B.; Ahmed, Yonis; Bhatnagar, Aruni

    2012-01-01

    SUMMARY Oxidation of unsaturated phospholipids results in the generation of aldehyde side chains that remain esterified to the phospholipid backbone. Such “core” aldehydes elicit immune responses and promote inflammation. However, the biochemical mechanisms by which phospholipid aldehydes are metabolized or detoxified are not well understood. In the studies reported here, we examined whether aldose reductase (AR), which reduces hydrophobic aldehydes, metabolizes phospholipid aldehydes. Incubation with AR led to the reduction of 5-oxovaleroyl, 7-oxo-5-heptenoyl, 5-hydroxy-6-oxo-caproyl, and 5-hydroxy-8-oxo-6-octenoyl phospholipids generated upon oxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PAPC). The enzyme also catalyzed the reduction of phospholipid aldehydes generated from the oxidation of 1-alkyl, and 1-alkenyl analogs of PAPC, and 1-palmitoyl-2-arachidonoyl phosphatidic acid or phosphoglycerol. Aldose reductase catalyzed the reduction of chemically synthesized 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphatidylcholine (POVPC) with a Km of 10 μM. Addition of POVPC to the culture medium led to incorporation and reduction of the aldehyde in COS-7 and THP-1 cells. Reduction of POVPC in these cells was prevented by the AR inhibitors sorbinil and tolrestat and was increased in COS-7 cells overexpressing AR. Together, these observations suggest that AR may be a significant participant in the metabolism of several structurally diverse phospholipid aldehydes. This metabolism may be a critical regulator of the pro-inflammatory and immunogenic effects of oxidized phospholipids. PMID:15465833

  5. The epimerization of peptide aldehydes--a systematic study.

    PubMed

    Ganneau, Cécile; Moulin, Aline; Demange, Luc; Martinez, Jean; Fehrentz, Jean-Alain

    2006-07-01

    Peptide aldehydes are interesting targets as enzyme inhibitors, and can be used for pseudopeptide chemistry or ligation. However, they are known to be subjected to epimerization during synthesis or purification. By (1)H NMR, a model dipeptide aldehyde can be used to check the possible epimerization occurring during synthesis. Various purification methods were investigated, but none was free from epimerization.

  6. Modulation of ethanol stress tolerance by aldehyde dehydrogenase in the mycorrhizal fungus Tricholoma vaccinum.

    PubMed

    Asiimwe, Theodore; Krause, Katrin; Schlunk, Ines; Kothe, Erika

    2012-08-01

    We report the first mycorrhizal fungal aldehyde dehydrogenase gene, ald1, which was isolated from the basidiomycete Tricholoma vaccinum. The gene, encoding a protein Ald1 of 502 amino acids, is up-regulated in ectomycorrhiza. Phylogenetic analyses using 53 specific fungal aldehyde dehydrogenases from all major phyla in the kingdom of fungi including Ald1 and two partial sequences of T. vaccinum were performed to get an insight in the evolution of the aldehyde dehydrogenase family. By using competitive and real-time RT-PCR, ald1 is up-regulated in response to alcohol and aldehyde-related stress. Furthermore, heterologous expression of ald1 in Escherichia coli and subsequent in vitro enzyme activity assay demonstrated the oxidation of propionaldehyde and butyraldehyde with different kinetics using either NAD(+) or NADP(+) as cofactors. In addition, overexpression of ald1 in T. vaccinum after Agrobacterium tumefaciens-mediated transformation increased ethanol stress tolerance. These results demonstrate the ability of Ald1 to circumvent ethanol stress, a critical function in mycorrhizal habitats.

  7. DEVELOPMENTAL EXPRESSION OF ALDEHYDE DEHYDROGENASE IN RAT: A COMPARISON OF LIVER AND LUNG DEVELOPMENT

    EPA Science Inventory

    Metabolism is one of the major determinants for age-related susceptibility changes to chemicals. Aldehydes are highly reactive molecules present in the environment and can be produced during biotransformation of xenobiotics. Aldehyde dehydrogenases (ALDH) are important in aldehyd...

  8. 14 CFR Section 10 - Functional Classification-Operating Expenses of Group I Air Carriers

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Functional Classification-Operating... REPORTS FOR LARGE CERTIFICATED AIR CARRIERS Profit and Loss Classification Section 10 Functional Classification—Operating Expenses of Group I Air Carriers 5100Flying Operations. (a) This function shall...

  9. Biogeographical Boundaries, Functional Group Structure and Diversity of Rocky Shore Communities along the Argentinean Coast

    PubMed Central

    Wieters, Evie A.; McQuaid, Christopher; Palomo, Gabriela; Pappalardo, Paula; Navarrete, Sergio A.

    2012-01-01

    We investigate the extent to which functional structure and spatial variability of intertidal communities coincide with major biogeographical boundaries, areas where extensive compositional changes in the biota are observed over a limited geographic extension. We then investigate whether spatial variation in the biomass of functional groups, over geographic (10′s km) and local (10′s m) scales, could be associated to species diversity within and among these groups. Functional community structure expressed as abundance (density, cover and biomass) and composition of major functional groups was quantified through field surveys at 20 rocky intertidal shores spanning six degrees of latitude along the southwest Atlantic coast of Argentina and extending across the boundaries between the Argentinean and Magellanic Provinces. Patterns of abundance of individual functional groups were not uniformly matched with biogeographical regions. Only ephemeral algae showed an abrupt geographical discontinuity coincident with changes in biogeographic boundaries, and this was limited to the mid intertidal zone. We identified 3–4 main ‘groups’ of sites in terms of the total and relative abundance of the major functional groups, but these did not coincide with biogeographical boundaries, nor did they follow latitudinal arrangement. Thus, processes that determine the functional structure of these intertidal communities are insensitive to biogeographical boundaries. Over both geographical and local spatial scales, and for most functional groups and tidal levels, increases in species richness within the functional group was significantly associated to increased total biomass and reduced spatial variability of the group. These results suggest that species belonging to the same functional group are sufficiently uncorrelated over space (i.e. metres and site-to-site ) to stabilize patterns of biomass variability and, in this manner, provide a buffer, or “insurance”, against spatial

  10. Succession of phytoplankton functional groups regulated by monsoonal hydrology in a large canyon-shaped reservoir.

    PubMed

    Xiao, Li-Juan; Wang, Tian; Hu, Ren; Han, Bo-Ping; Wang, Sheng; Qian, Xin; Padisák, Judit

    2011-10-15

    Liuxihe reservoir is a deep, monomictic, oligo-mesotrophic canyon-reservoir in the subtropical monsoon climate region of southern China. Phytoplankton functional groups in the reservoir were investigated and a comparison made between the succession observed in 2008, an exceptionally wet year, and 2009, an average year. The reservoir shows strong annual fluctuations in water level caused by monsoon rains and artificial drawdown. Altogether 28 functional groups of phytoplankton were identified, including 79 genera. Twelve of the groups were analyzed in detail using redundancy analysis. Because of the oligo-mesotrophic and P-limited condition of the reservoir, the dominant functional groups were those tolerant of nutrient (phosphorus) deficiency. The predominant functional groups in the succession process were Groups A (Cyclotella with greatest axial linear dimension<10 μm), B (Cyclotella with greatest axial linear dimension>10 μm), LO (Peridinium), LM (Ceratium and Microcystis), E (Dinobryon and Mallomonas), F (Botryococcus), X1 (Ankistrodesmus, Ankyra, Chlorella and Monoraphidium) and X2 (Chlamydomonas and Chroomonas). The development of groups A, B and LO was remarkably seasonal. Group A was dominant during stratification, when characteristic small size and high surface/volume ratio morphology conferred an advantage. Group LO was dominant during dry stratification, when motility was advantageous. Group B plankton exhibited a high relative biomass during periods of reduced euphotic depth and isothermy. Groups LM, E, F, X1 and X2 occasionally exhibited high relative biomasses attributable to specific environmental events (e.g. drawdown, changes in zooplankton community). A greater diversity of phytoplankton functional groups was apparent during isothermy. This study underscores the usefulness of functional algal groups in studying succession in subtropical impoundments, in which phytoplankton succession can be significantly affected by external factors such as

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  12. Variation of phytoplankton functional groups modulated by hydraulic controls in Hongze Lake, China.

    PubMed

    Tian, Chang; Pei, Haiyan; Hu, Wenrong; Hao, Daping; Doblin, Martina A; Ren, Ying; Wei, Jielin; Feng, Yawei

    2015-11-01

    Hongze Lake is a large, shallow, polymictic, eutrophic lake in the eastern China. Phytoplankton functional groups in this lake were investigated from March 2011 to February 2013, and a comparison was made between the eastern, western, and northern regions. The lake shows strong fluctuations in water level caused by monsoon rains and regular hydraulic controls. By application of the phytoplankton functional group approach, this study aims to investigate the spatial and temporal dynamics and analyze their influencing factors. Altogether, 18 functional groups of phytoplankton were identified, encompassing 187 species. In order to seek the best variable describing the phytoplankton functional group distribution, 14 of the groups were analyzed in detail using redundancy analysis. Due to the turbid condition of the lake, the dominant functional groups were those tolerant of low light. The predominant functional groups in the annual succession were D (Cyclotella spp. and Synedra acus), T (Planctonema lauterbornii), P (Fragilaria crotonensis), X1 (Chlorella vulgaris and Chlorella pyrenoidosa), C (Cyclotella meneghiniana and Cyclotella ocellata), and Y (Cryptomonas erosa). An opposite relationship between water level and the biomass of predominant groups was observed in the present study. Water level fluctuations, caused by monsoonal climate and artificial drawdown, were significant factors influencing phytoplankton succession in Hongze Lake, since they alter the hydrological conditions and influence light and nutrient availability. The clearly demonstrated factors, which significantly influence phytoplankton dynamics in Hongze Lake, will help government manage the large shallow lakes with frequent water level fluctuations.

  13. Redundancy and response diversity of functional groups: implications for the resilience of coral reefs.

    PubMed

    Nyström, Magnus

    2006-02-01

    To improve coral reef management, a deeper understanding of biodiversity across scales in the context of functional groups is required. The focus of this paper is on the role of diversity within functional groups in securing important ecosystem processes that contribute to the resilience of coral-dominated reef states. Two important components of species biodiversity that confer ecosystem resilience are analyzed: redundancy and the diversity of responses within functional groups to change. Three critical functional groups are used to illustrate the interaction between these two components and their role in coral reef resilience: zooxanthellae (symbiotic micro algae in reef-building corals), reef-building corals, and herbivores. The paper further examines the consequences of undermining functional redundancy and response diversity and addresses strategies to secure ecological processes that are critical for coral reef resilience.

  14. A first principle study of graphene functionalized with hydroxyl, nitrile, or methyl groups

    NASA Astrophysics Data System (ADS)

    Barhoumi, M.; Rocca, D.; Said, M.; Lebègue, S.

    2017-01-01

    By means of ab initio calculations, we study the functionalization of graphene by different chemical groups such as hydroxyl, nitrile, or methyl. Two extreme cases of functionalization are considered: a single group on a supercell of graphene and a sheet of graphene fully functionalized. Once the equilibrium geometry is obtained by density functional theory, we found that the systems are metallic when a single group is attached to the sheet of graphene. With the exception of the nitrile functionalized boat configuration, a large bandgap is obtained at full coverage. Specifically, by using the GW approximation, our calculated bandgaps are direct and range between 5.0 and 5.5 eV for different configurations of hydroxyl functionalized graphene. An indirect GW bandgap of 6.50 eV was found in nitrile functionalized graphene while the methyl group functionalization leads to a direct bandgap with a value of 4.50 eV. Since in the two limiting cases of minimal and full coverage, the electronic structure changes drastically from a metal to a wide bandgap semiconductor, a series of intermediate states might be expected by tuning the amount of functionalization with these different groups.

  15. Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Chan, A. W. H.; Chan, M. N.; Surratt, J. D.; Chhabra, P. S.; Loza, C. L.; Crounse, J. D.; Yee, L. D.; Flagan, R. C.; Wennberg, P. O.; Seinfeld, J. H.

    2010-08-01

    Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C4-unsaturated aldehyde) under urban high-NOx conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NOx regime. Here we show that as a result of this chemistry, NO2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NOx effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO2 conditions, as PAN (peroxy acyl nitrate, RC(O)OONO2) formation is structurally unfavorable. At atmospherically relevant NO2/NO ratios (3-8), the SOA yields from isoprene high-NOx photooxidation are 3 times greater than previously measured at lower NO2/NO ratios. At sufficiently high NO2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO2 can exceed that from RO2+HO2 reactions under the same inorganic seed conditions, making RO2+NO2 an important channel for SOA formation.

  16. Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Chan, A. W. H.; Chan, M. N.; Surratt, J. D.; Chhabra, P. S.; Loza, C. L.; Crounse, J. D.; Yee, L. D.; Flagan, R. C.; Wennberg, P. O.; Seinfeld, J. H.

    2010-04-01

    Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C4-unsaturated aldehyde) under urban high-NOx conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NOx regime. Here we show that as a result of this chemistry, NO2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NOx effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO2 conditions, as PAN (peroxy acyl nitrate, RC(O)OONO2) formation is structurally unfavorable. At atmospherically relevant NO2/NO ratios, the SOA yields from isoprene high-NOxphotooxidation are 3 times greater than previously measured at lower NO2/NO ratios. At sufficiently high NO2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO2 can exceed that from RO2+HO2 reactions under the same inorganic seed conditions, making RO2+NO2 an important channel for SOA formation.

  17. Aldehyde modification and alum coadjuvancy enhance anti-TNF-α autovaccination and mitigate arthritis in rat.

    PubMed

    Bavoso, Alfonso; Ostuni, Angela; De Vendel, Jolanda; Bracalello, Angelo; Shcheglova, Tatiana; Makker, Sudesh; Tramontano, Alfonso

    2015-05-01

    Experimental vaccination to induce antibodies (Abs) capable of cytokine antagonism shows promise as a novel immunotherapy for chronic inflammatory disease. We prepared a hybrid antigen consisting of residues 141-235 of rat TNF-α fused to the C-terminus of glutathione-S-transferase (GST), chemically modified to incorporate aldehyde residues, for development of an auto-vaccine eliciting anti-rTNF-α Abs. In rat immunization the soluble aldehyde-modified fusion protein did not generate observable Ab responses. By contrast, vaccination with the aldehyde-modified fusion protein adsorbed on alum induced anti-TNF-α autoAbs with high titer and neutralizing activity. Induction of adjuvant arthritis in rats pre-immunized with unmodified fusion protein or a control protein in alum resulted in severe inflammation and joint damage, whereas the disease induced in rats immunized with the aldehyde-bearing fusion protein in alum was markedly attenuated. Similar results were obtained in a collagen-induced rat arthritis model. Anti-collagen II IgG Ab titers did not deviate significantly in groups pre-immunized with modified fusion protein and control protein, suggesting that anti-TNF vaccination did not skew the immune response related to disease induction. This study demonstrates synergy between particulate alum and protein bound carbonyl residues for enhancement of protein immunogenicity. The antigen-specific co-adjuvant system could prove advantageous for breaking tolerance in emerging auto-vaccination therapies targeting inflammatory cytokines as well as for enhancing a broader category of subunit vaccines. Aldehyde adduction introduces a minimal modification which, together with the established use of alum as a safe adjuvant for human use, could be favorable for further vaccine development.

  18. Stereochemistry of the allylation and crotylation reactions of alpha-methyl-beta-hydroxy aldehydes with allyl- and crotyltrifluorosilanes. Synthesis of anti,anti-dipropionate stereotriads and stereodivergent pathways for the reactions with 2,3-anti- and 2,3-syn-alpha-methyl-beta-hydroxy aldehydes.

    PubMed

    Chemler, Sherry R; Roush, William R

    2003-02-21

    A new method for the stereoselective synthesis of the anti,anti-dipropionate stereotriad via the reaction of alpha-methyl-beta-hydroxy aldehydes with (Z)-crotyltrifluorosilane (24) is described. These reactions were designed to occur through bicyclic transition states (e.g., 31) in which the silane reagent is covalently bound to the beta-hydroxyl group of the aldehyde and the crotyl group is transferred intramolecularly. This methodology was used to synthesize the C(7)-C(16) segment (58) of zincophorin, which contains a synthetically challenging all-anti stereopentad unit. Surprisingly, 2,3-anti- and 2,3-syn-alpha-methyl-beta-hydroxy aldehydes react in a stereodivergent manner with 24: 2,3-anti-beta-hydroxy aldehydes give the targeted anti,anti-dipropionate adducts with high selectivity, but the reactions of 2,3-syn-beta-hydroxy aldehydes are poorly selective. The stereodivergent behavior of 2,3-syn- vs 2,3-anti-alpha-methyl-beta-hydroxy aldehydes is also exhibited in their reactions with the allyl- (68) and (E)-crotyltrifluorosilanes (27). Competition experiments performed with beta-hydroxy aldehydes 37a (anti) and the corresponding p-methoxybenzyl (PMB) ether 48, and between aldehyde 39 (syn) and the PMB ether 90, established that the 2,3-anti-beta-hydroxy aldehydes react predominantly through bicyclic transition states while the 2,3-syn aldehydes react predominantly through conventional Zimmerman-Traxler transition states. NMR studies established that both the 2,3-syn and the 2,3-anti aldehydes form stable, pentavalent silicate intermediates (98 and 100) with PhSiF(3), but chelated structures 99 and 101 could not be detected. The activation energies for the competing bicyclic and conventional Zimmerman-Traxler transition states were calculated by using semiemperical methods (MNDO/d). These calculations indicate that the stereodivergent behavior of the 2,3-syn-beta-hydroxy aldehydes and the 2,3-anti-beta-hydroxy aldehydes is due to differences in nonbonded

  19. a Renormalization Group Calculation of the Velocity - and Density-Density Correlation Functions.

    NASA Astrophysics Data System (ADS)

    Cowan, Mark Timothy

    The velocity-velocity correlation function of a free field theory is obtained. The renormalization group, along with a 4-varepsilon expansion, is then used to find the leading order behavior of the velocity-velocity correlation function for an interacting field theory in the high temperature phase near the critical point. The details of the calculation of the density-density correlation function for Hedgehogs, in the context of a free field theory, is presented next. Finally the renormalization group, along with a 4-varepsilon expansion, is used to find the leading order behavior of the density-density correlation function for Hedgehogs in an interacting field theory near the critical point.

  20. Identification of long chain specific aldehyde reductase and its use in enhanced fatty alcohol production in E. coli.

    PubMed

    Fatma, Zia; Jawed, Kamran; Mattam, Anu Jose; Yazdani, Syed Shams

    2016-09-01

    Long chain fatty alcohols have wide application in chemical industries and transportation sector. There is no direct natural reservoir for long chain fatty alcohol production, thus many groups explored metabolic engineering approaches for its microbial production. Escherichia coli has been the major microbial platform for this effort, however, terminal endogenous enzyme responsible for converting fatty aldehydes of chain length C14-C18 to corresponding fatty alcohols is still been elusive. Through our in silico analysis we selected 35 endogenous enzymes of E. coli having potential of converting long chain fatty aldehydes to fatty alcohols and studied their role under in vivo condition. We found that deletion of ybbO gene, which encodes NADP(+) dependent aldehyde reductase, led to >90% reduction in long chain fatty alcohol production. This feature was found to be strain transcending and reinstalling ybbO gene via plasmid retained the ability of mutant to produce long chain fatty alcohols. Enzyme kinetic study revealed that YbbO has wide substrate specificity ranging from C6 to C18 aldehyde, with maximum affinity and efficiency for C18 and C16 chain length aldehyde, respectively. Along with endogenous production of fatty aldehyde via optimized heterologous expression of cyanobaterial acyl-ACP reductase (AAR), YbbO overexpression resulted in 169mg/L of long chain fatty alcohols. Further engineering involving modulation of fatty acid as well as of phospholipid biosynthesis pathway improved fatty alcohol production by 60%. Finally, the engineered strain produced 1989mg/L of long chain fatty alcohol in bioreactor under fed-batch cultivation condition. Our study shows for the first time a predominant role of a single enzyme in production of long chain fatty alcohols from fatty aldehydes as well as of modulation of phospholipid pathway in increasing the fatty alcohol production.

  1. Controlling surface functionality through generation of thiol groups in a self-assembled monolayer.

    SciTech Connect

    Lud, S. Q.; Neppl, S.; Richter, G.; Bruno, P.; Gruen, D. M.; Jordan, R.; Feulner, P.; Stutzmann, M.; Garrido, J. A.; Materials Science Division; Technische Univ. Munchen

    2010-01-01

    A lithographic method to generate reactive thiol groups on functionalized synthetic diamond for biosensor and molecular electronic applications is developed. We demonstrate that ultrananocrystalline diamond (UNCD) thin films covalently functionalized with surface-generated thiol groups allow controlled thiol-disulfide exchange surface hybridization processes. The generation of the thiol functional head groups was obtained by irradiating phenylsulfonic acid (PSA) monolayers on UNCD surfaces. The conversion of the functional headgroup of the self-assembled monolayer was verified by using X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), and fluorescence microscopy. Our findings indicate the selective generation of reactive thiol surface groups. Furthermore, we demonstrate the grafting of yeast cytochrome c to the thiol-modified diamond surface and the electron transfer between protein and electrode.

  2. Illustrating the Use of Nonparametric Regression To Assess Differential Item and Bundle Functioning among Multiple Groups.

    ERIC Educational Resources Information Center

    Gierl, Mark J.; Bolt, Daniel M.

    2001-01-01

    Presents an overview of nonparametric regression as it allies to differential item functioning analysis and then provides three examples to illustrate how nonparametric regression can be applied to multilingual, multicultural data to study group differences. (SLD)

  3. Insight into Coenzyme A cofactor binding and the mechanism of acyl-transfer in an acylating aldehyde dehydrogenase from Clostridium phytofermentans

    PubMed Central

    Tuck, Laura R.; Altenbach, Kirsten; Ang, Thiau Fu; Crawshaw, Adam D.; Campopiano, Dominic J.; Clarke, David J.; Marles-Wright, Jon

    2016-01-01

    The breakdown of fucose and rhamnose released from plant cell walls by the cellulolytic soil bacterium Clostridium phytofermentans produces toxic aldehyde intermediates. To enable growth on these carbon sources, the pathway for the breakdown of fucose and rhamnose is encapsulated within a bacterial microcompartment (BMC). These proteinaceous organelles sequester the toxic aldehyde intermediates and allow the efficient action of acylating aldehyde dehydrogenase enzymes to produce an acyl-CoA that is ultimately used in substrate-level phosphorylation to produce ATP. Here we analyse the kinetics of the aldehyde dehydrogenase enzyme from the fucose/rhamnose utilisation BMC with different short-chain fatty aldehydes and show that it has activity against substrates with up to six carbon atoms, with optimal activity against propionaldehyde. We have also determined the X-ray crystal structure of this enzyme in complex with CoA and show that the adenine nucleotide of this cofactor is bound in a distinct pocket to the same group in NAD+. This work is the first report of the structure of CoA bound to an aldehyde dehydrogenase enzyme and our crystallographic model provides important insight into the differences within the active site that distinguish the acylating from non-acylating aldehyde dehydrogenase enzymes. PMID:26899032

  4. Functional group placement in protein binding sites: a comparison of GRID and MCSS

    NASA Astrophysics Data System (ADS)

    Bitetti-Putzer, Ryan; Joseph-McCarthy, Diane; Hogle, James M.; Karplus, Martin

    2001-10-01

    One approach to combinatorial ligand design begins by determining optimal locations (i.e., local potential energy minima) for functional groups in the binding site of a target macromolecule. MCSS and GRID are two methods, based on significantly different algorithms, which are used for this purpose. A comparison of the two methods for the same functional groups is reported. Calculations were performed for nonpolar and polar functional groups in the internal hydrophobic pocket of the poliovirus capsid protein, and on the binding surface of the src SH3 domain. The two approaches are shown to agree qualitatively; i.e., the global characteristics of the functional group maps generated by MCSS and GRID are similar. However, there are significant differences in the relative interaction energies of the two sets of minima, a consequence of the different functional form used to evaluate polar interactions (electrostatics and hydrogen bonding) in the two methods. The single sphere representation used by GRID affords only positional information, supplemented by the identification of hydrogen bonding interactions. By contrast, the multi-atom representation of most MCSS groups yields in both positional and orientational information. The two methods are most similar for small functional groups, while for larger functional groups MCSS yields results consistent with GRID but superior in detail. These results are in accord with the somewhat different purposes for which the two methods were developed. GRID has been used mainly to introduce functionalities at specific positions in lead compounds, in which case the orientation is predetermined by the structure of the latter. The orientational information provided by MCSS is important for its use in the de novo design of large, multi-functional ligands, as well as for improving lead compounds.

  5. A Functional Group Approach for Prediction of APPI Response of Organic Synthetic Targets

    NASA Astrophysics Data System (ADS)

    Zhurov, Konstantin O.; Menin, Laure; Di Franco, Thomas; Tsybin, Yury O.

    2015-07-01

    Atmospheric pressure photoionization (APPI) is a technique of choice for ionization of non-polar molecules in mass spectrometry (MS). Reported APPI-based studies tend to focus on a selected compound class, which may contain a variety of functional groups. These studies demonstrate that APPI response frequently differs substantially, indicating a certain dependence on the functional group present. Although this dependence could be employed for APPI response prediction, its systematic use is currently absent. Here, we apply APPI MS to a judiciously-compiled set of 63 compounds containing a number of diverse functional groups commonly utilized in synthesis, reactive functional groups, as well as those containing boron and silicon. Based on the outcome of APPI MS of these compounds, we propose and evaluate a simple guideline to estimate the APPI response for a novel compound, the key properties of which have not been characterized in the gas phase. Briefly, we first identify key functional groups in the compound and gather knowledge on the known ionization energies from the smallest analogues containing said functional groups. We then consider local inductive and resonance effects on said ionization energies for the compounds of interest to estimate the APPI response. Finally, application of APPI MS to compounds of interest considered herein demonstrated extended upper mass ionization limit of 3.5 kDa for non-polymeric compounds.

  6. Multiple-Group Noncompensatory Differential Item Functioning in Raju's Differential Functioning of Items and Tests

    ERIC Educational Resources Information Center

    Oshima, T. C.; Wright, Keith; White, Nick

    2015-01-01

    Raju, van der Linden, and Fleer (1995) introduced a framework for differential functioning of items and tests (DFIT) for unidimensional dichotomous models. Since then, DFIT has been shown to be a quite versatile framework as it can handle polytomous as well as multidimensional models both at the item and test levels. However, DFIT is still limited…

  7. Identification of Differential Item Functioning in Multiple-Group Settings: A Multivariate Outlier Detection Approach

    ERIC Educational Resources Information Center

    Magis, David; De Boeck, Paul

    2011-01-01

    We focus on the identification of differential item functioning (DIF) when more than two groups of examinees are considered. We propose to consider items as elements of a multivariate space, where DIF items are outlying elements. Following this approach, the situation of multiple groups is a quite natural case. A robust statistics technique is…

  8. The Use of Language Functions in Mathematical Group Games. Teacher Insights.

    ERIC Educational Resources Information Center

    Black, Carolyn; Huerta, Maria G.

    1994-01-01

    Six group games were introduced into a second-grade bilingual classroom. Children's talk during each game was classified using a modification of Dyson's five language functions (representational, directive, heuristic, personal, and interactional). Group games provided many communication opportunities. Some children tried new communication styles.…

  9. Characteristics of Interactional Management Functions in Group Oral by Japanese Learners of English

    ERIC Educational Resources Information Center

    Negishi, Junko

    2010-01-01

    This study attempted to investigate the characteristics of interaction dynamics in a group oral interaction carried out by Japanese learners of English. The relationship between the participants' language development and interactional management functions (IMFs) was also explored. Oral performance tests in a paired or a small group have recently…

  10. Functional Groups Based on Leaf Physiology: Are they Spatially and Temporally Robust?

    NASA Technical Reports Server (NTRS)

    Foster, Tammy E.; Brooks, J. Renee

    2004-01-01

    The functional grouping hypothesis, which suggests that complexity in ecosystem function can be simplified by grouping species with similar responses, was tested in the Florida scrub habitat. Functional groups were identified based on how species in fire maintained Florida scrub regulate exchange of carbon and water with the atmosphere as indicated by both instantaneous gas exchange measurements and integrated measures of function (%N, delta C-13, delta N-15, C-N ratio). Using cluster analysis, five distinct physiologically-based functional groups were identified in the fire maintained scrub. These functional groups were tested to determine if they were robust spatially, temporally, and with management regime. Analysis of Similarities (ANOSIM), a non-parametric multivariate analysis, indicated that these five physiologically-based groupings were not altered by plot differences (R = -0.115, p = 0.893) or by the three different management regimes; prescribed burn, mechanically treated and burn, and fire-suppressed (R = 0.018, p = 0.349). The physiological groupings also remained robust between the two climatically different years 1999 and 2000 (R = -0.027, p = 0.725). Easy-to-measure morphological characteristics indicating functional groups would be more practical for scaling and modeling ecosystem processes than detailed gas-exchange measurements, therefore we tested a variety of morphological characteristics as functional indicators. A combination of non-parametric multivariate techniques (Hierarchical cluster analysis, non-metric Multi-Dimensional Scaling, and ANOSIM) were used to compare the ability of life form, leaf thickness, and specific leaf area classifications to identify the physiologically-based functional groups. Life form classifications (ANOSIM; R = 0.629, p 0.001) were able to depict the physiological groupings more adequately than either specific leaf area (ANOSIM; R = 0.426, p = 0.001) or leaf thickness (ANOSIM; R 0.344, p 0.001). The ability of

  11. Percolation galaxy groups and clusters in the sdss redshift survey: identification, catalogs, and the multiplicity function

    SciTech Connect

    Berlind, Andreas A.; Frieman, Joshua A.; Weinberg, David H.; Blanton, Michael R.; Warren, Michael S.; Abazajian, Kevork; Scranton, Ryan; Hogg, David W.; Scoccimarro, Roman; Bahcall, Neta A.; Brinkmann, J.; Gott, J.Richard, III; Kleinman, S.J.; Krzesinski, J.; Lee, Brian C.; Miller, Christopher J.; Nitta, Atsuko; Schneider, Donald P.; Tucker, Douglas L.; Zehavi, Idit; /CCPP, New York /Chicago U., Astron. Astrophys. Ctr. /Ohio State U., Dept. Astron. /Los Alamos /Pittsburgh U. /Princeton U. /Subaru Telescope /Apache Point Observ. /Mt. Suhora Observ., Cracow /LBL, Berkeley /Cerro-Tololo InterAmerican Obs. /Penn State U., Astron. Astrophys. /Fermilab /Arizona U., Astron. Dept. - Steward Observ. /Case Western Reserve U.

    2006-01-01

    We identify galaxy groups and clusters in volume-limited samples of the SDSS redshift survey, using a redshift-space friends-of-friends algorithm. We optimize the friends-of-friends linking lengths to recover galaxy systems that occupy the same dark matter halos, using a set of mock catalogs created by populating halos of N-body simulations with galaxies. Extensive tests with these mock catalogs show that no combination of perpendicular and line-of-sight linking lengths is able to yield groups and clusters that simultaneously recover the true halo multiplicity function, projected size distribution, and velocity dispersion. We adopt a linking length combination that yields, for galaxy groups with ten or more members: a group multiplicity function that is unbiased with respect to the true halo multiplicity function; an unbiased median relation between the multiplicities of groups and their associated halos; a spurious group fraction of less than {approx}1%; a halo completeness of more than {approx}97%; the correct projected size distribution as a function of multiplicity; and a velocity dispersion distribution that is {approx}20% too low at all multiplicities. These results hold over a range of mock catalogs that use different input recipes of populating halos with galaxies. We apply our group-finding algorithm to the SDSS data and obtain three group and cluster catalogs for three volume-limited samples that cover 3495.1 square degrees on the sky. We correct for incompleteness caused by fiber collisions and survey edges, and obtain measurements of the group multiplicity function, with errors calculated from realistic mock catalogs. These multiplicity function measurements provide a key constraint on the relation between galaxy populations and dark matter halos.

  12. Loop expansion of the average effective action in the functional renormalization group approach

    NASA Astrophysics Data System (ADS)

    Lavrov, Peter M.; Merzlikin, Boris S.

    2015-10-01

    We formulate a perturbation expansion for the effective action in a new approach to the functional renormalization group method based on the concept of composite fields for regulator functions being their most essential ingredients. We demonstrate explicitly the principal difference between the properties of effective actions in these two approaches existing already on the one-loop level in a simple gauge model.

  13. New method of the functional renormalization group approach for Yang-Mills fields

    NASA Astrophysics Data System (ADS)

    Lavrov, P. M.; Shapiro, I. L.

    2014-12-01

    We propose a new formulation of the functional renormalization group (FRG) approach, based on the use of regulator functions as composite operators. In this case one can provide (in contrast with standard approach) on-shell gauge-invariance for the effective average action.

  14. Lung function decline rates according to GOLD group in patients with chronic obstructive pulmonary disease

    PubMed Central

    Kim, Joohae; Yoon, Ho Il; Oh, Yeon-Mok; Lim, Seong Yong; Lee, Ji-Hyun; Kim, Tae-Hyung; Lee, Sang Yeub; Lee, Jin Hwa; Lee, Sang-Do; Lee, Chang-Hoon

    2015-01-01

    Background Since the Global Initiative for Chronic Obstructive Lung Disease (GOLD) groups A–D were introduced, the lung function changes according to group have been evaluated rarely. Objective We investigated the rate of decline in annual lung function in patients categorized according to the 2014 GOLD guidelines. Methods Patients with COPD included in the Korean Obstructive Lung Disease (KOLD) prospective study, who underwent yearly postbronchodilator spirometry at least three times, were included. The main outcome was the annual decline in postbronchodilator forced expiratory volume in 1 second (FEV1), which was analyzed by random-slope and random-intercept mixed linear regression. Results A total 175 participants were included. No significant postbronchodilator FEV1 decline was observed between the groups (−34.4±7.9 [group A]; −26.2±9.4 [group B]; −22.7±16.0 [group C]; and −24.0±8.7 mL/year [group D]) (P=0.79). The group with less symptoms (−32.3±7.2 vs −25.0±6.5 mL/year) (P=0.44) and the low risk group (−31.0±6.1 vs −23.6±7.7 mL/year) (P=0.44) at baseline showed a more rapid decline in the postbronchodilator FEV1, but the trends were not statistically significant. However, GOLD stages classified by FEV1 were significantly related to the annual lung function decline. Conclusion There was no significant difference in lung function decline rates according to the GOLD groups. Prior classification using postbronchodilator FEV1 predicts decline in lung function better than does the new classification. PMID:26379432

  15. The electrokinetic characterization of gold nanoparticles, functionalized with cationic functional groups, and its' interaction with DNA.

    PubMed

    Lazarus, Geraldine Genevive; Revaprasadu, Neerish; López-Viota, Julián; Singh, Moganavelli

    2014-09-01

    Gold nanoparticles have attracted strong biomedical interest for drug delivery due to their low toxic nature, surface plasmon resonance and capability of increasing the stability of the payload. However, gene transfection represents another important biological application. Considering that cellular barriers keep enclosed their secret to deliver genes using nanoparticles, an important step can be achieved by studying the functionalization of nanoparticles with DNA. In the present contribution the synthesis of nanoparticles consisting of a gold core coated with one or more layers of amino acid (l-lysine), and cationic polyelectrolytes (poly-ethyleneimine and poly-l-lysine) is reported. All nanoparticles were subjected to dynamic light scattering, electrophoretic mobility measurements, UV-vis optical spectrophotometry analysis and transmission electron microscopy imaging. In addition, the adsorption of DNA plasmid (pSGS) with linear and supercoiled configurations was studied for those gold nanoparticles under the most suitable surface modifications. Preliminary results showed that the gold nanoparticles functionalized with poly-ethyleneimine and poly-l-lysine, respectively, and bound to linear DNA configurations, present in absolute value a higher electrophoretic mobility irrespective of the pH of the media, compared to the supercoiled and nicked configuration. The findings from this study suggest that poly-ethyleneimine and poly-l-lysine functionalized gold nanoparticles are biocompatible and may be promising in the chemical design and future optimization of nanostructures for biomedical applications such as gene and drug delivery.

  16. Vasodilatory effect of nitroglycerin in Japanese subjects with different aldehyde dehydrogenase 2 (ALDH2) genotypes.

    PubMed

    Miura, Takeshi; Nishinaka, Toru; Terada, Tomoyuki; Yonezawa, Kazuya

    2017-03-23

    The functional genetic polymorphism of aldehyde dehydrogenase 2 (ALDH2) influences the enzymatic activities of its wild type (Glu504 encoded by ALDH2*1) and mutant type (Lys504 encoded by ALDH2*2) proteins. The enzymatic activities of mutant-type ALDH2 are limited compared with those of the wild type. ALDH2 has been suggested as a critical factor for nitroglycerin-mediated vasodilation by some human studies and in vitro studies. Currently, there is no research on direct observations of the vasodilatory effect of nitroglycerin sublingual tablets, which is the generally used dosage form. In the present study, the contribution of ALDH2 to the vasodilatory effect of nitroglycerin sublingual tablets was investigated among three genotype groups (ALDH2*1/*1, ALDH2*1/*2, and ALDH2*2/*2) in Japanese. The results by direct assessments of in vivo nitroglycerin-mediated dilation showed no apparent difference in vasodilation among all genotypes of ALDH2. Furthermore, to analyze the effect of other factors (age and flow-mediated dilation), multiple regression analysis and Pearson's correlation coefficient analysis were carried out. These analyses also indicated that the genotypes of ALDH2 were not related to the degree of vasodilation. These results suggest the existence of other predominant pathway(s) for nitroglycerin biotransformation, at least with regard to clinical nitroglycerin (e.g., a sublingual tablet) in Japanese subjects.

  17. Molecular Response to Toxic Diatom-Derived Aldehydes in the Sea Urchin Paracentrotus lividus

    PubMed Central

    Varrella, Stefano; Romano, Giovanna; Ianora, Adrianna; Bentley, Matt G.; Ruocco, Nadia; Costantini, Maria

    2014-01-01

    Diatoms are dominant photosynthetic organisms in the world’s oceans and represent a major food source for zooplankton and benthic filter-feeders. However, their beneficial role in sustaining marine food webs has been challenged after the discovery that they produce secondary metabolites, such as polyunsaturated aldehydes (PUAs), which negatively affect the reproductive success of many invertebrates. Here, we report the effects of two common diatom PUAs, heptadienal and octadienal, which have never been tested before at the molecular level, using the sea urchin, Paracentrotus lividus, as a model organism. We show that both PUAs are able to induce teratogenesis (i.e., malformations), as already reported for decadienal, the better-studied PUA of this group. Moreover, post-recovery experiments show that embryos can recover after treatment with all three PUAs, indicating that negative effects depend both on PUA concentrations and the exposure time of the embryos to these metabolites. We also identify the time range during which PUAs exert the greatest effect on sea urchin embryogenesis. Finally, we report the expression levels of thirty one genes (having a key role in a broad range of functional responses, such as stress, development, differentiation, skeletogenesis and detoxification processes) in order to identify the common targets affected by PUAs and their correlation with morphological abnormalities. This study opens new perspectives for understanding how marine organisms afford protection from environmental toxicants through an integrated network of genes. PMID:24714125

  18. Molecular response to toxic diatom-derived aldehydes in the sea urchin Paracentrotus lividus.

    PubMed

    Varrella, Stefano; Romano, Giovanna; Ianora, Adrianna; Bentley, Matt G; Ruocco, Nadia; Costantini, Maria

    2014-04-04

    Diatoms are dominant photosynthetic organisms in the world's oceans and represent a major food source for zooplankton and benthic filter-feeders. However, their beneficial role in sustaining marine food webs has been challenged after the discovery that they produce secondary metabolites, such as polyunsaturated aldehydes (PUAs), which negatively affect the reproductive success of many invertebrates. Here, we report the effects of two common diatom PUAs, heptadienal and octadienal, which have never been tested before at the molecular level, using the sea urchin, Paracentrotus lividus, as a model organism. We show that both PUAs are able to induce teratogenesis (i.e., malformations), as already reported for decadienal, the better-studied PUA of this group. Moreover, post-recovery experiments show that embryos can recover after treatment with all three PUAs, indicating that negative effects depend both on PUA concentrations and the exposure time of the embryos to these metabolites. We also identify the time range during which PUAs exert the greatest effect on sea urchin embryogenesis. Finally, we report the expression levels of thirty one genes (having a key role in a broad range of functional responses, such as stress, development, differentiation, skeletogenesis and detoxification processes) in order to identify the common targets affected by PUAs and their correlation with morphological abnormalities. This study opens new perspectives for understanding how marine organisms afford protection from environmental toxicants through an integrated network of genes.

  19. Functional specialization and generalization for grouping of stimuli based on colour and motion

    PubMed Central

    Zeki, Semir; Stutters, Jonathan

    2013-01-01

    This study was undertaken to learn whether the principle of functional specialization that is evident at the level of the prestriate visual cortex extends to areas that are involved in grouping visual stimuli according to attribute, and specifically according to colour and motion. Subjects viewed, in an fMRI scanner, visual stimuli composed of moving dots, which could be either coloured or achromatic; in some stimuli the moving coloured dots were randomly distributed or moved in random directions; in others, some of the moving dots were grouped together according to colour or to direction of motion, with the number of groupings varying from 1 to 3. Increased activation was observed in area V4 in response to colour grouping and in V5 in response to motion grouping while both groupings led to activity in separate though contiguous compartments within the intraparietal cortex. The activity in all the above areas was parametrically related to the number of groupings, as was the prominent activity in Crus I of the cerebellum where the activity resulting from the two types of grouping overlapped. This suggests (a) that, the specialized visual areas of the prestriate cortex have functions beyond the processing of visual signals according to attribute, namely that of grouping signals according to colour (V4) or motion (V5); (b) that the functional separation evident in visual cortical areas devoted to motion and colour, respectively, is maintained at the level of parietal cortex, at least as far as grouping according to attribute is concerned; and (c) that, by contrast, this grouping-related functional segregation is not maintained at the level of the cerebellum. PMID:23415950

  20. Classifying proteins into functional groups based on all-versus-all BLAST of 10 million proteins.

    PubMed

    Kolker, Natali; Higdon, Roger; Broomall, William; Stanberry, Larissa; Welch, Dean; Lu, Wei; Haynes, Winston; Barga, Roger; Kolker, Eugene

    2011-01-01

    To address the monumental challenge of assigning function to millions of sequenced proteins, we completed the first of a kind all-versus-all sequence alignments using BLAST for 9.9 million proteins in the UniRef100 database. Microsoft Windows Azure produced over 3 billion filtered records in 6 days using 475 eight-core virtual machines. Protein classification into functional groups was then performed using Hive and custom jars implemented on top of Apache Hadoop utilizing the MapReduce paradigm. First, using the Clusters of Orthologous Genes (COG) database, a length normalized bit score (LNBS) was determined to be the best similarity measure for classification of proteins. LNBS achieved sensitivity and specificity of 98% each. Second, out of 5.1 million bacterial proteins, about two-thirds were assigned to significantly extended COG groups, encompassing 30 times more assigned proteins. Third, the remaining proteins were classified into protein functional groups using an innovative implementation of a single-linkage algorithm on an in-house Hadoop compute cluster. This implementation significantly reduces the run time for nonindexed queries and optimizes efficient clustering on a large scale. The performance was also verified on Amazon Elastic MapReduce. This clustering assigned nearly 2 million proteins to approximately half a million different functional groups. A similar approach was applied to classify 2.8 million eukaryotic sequences resulting in over 1 million proteins being assign to existing KOG groups and the remainder clustered into 100,000 functional groups.

  1. The impact of functional group on the electronic structure of coordination center

    NASA Astrophysics Data System (ADS)

    Hooshmand Gharehbagh, Zahra; L, Duy; Rahman, Talat S.

    While 9, 10 dicyano-anthracene (DCA) forms a coordination network on Cu(111) surface with Cu adatom coordinated by three DCA molecules, its isomers, 9,10-diisocyano-anthracene forms, surprisingly, molecular rows on the same surface. To understand the impact of functional groups on the electronic structure of the coordination center, we have carried out density functional theory based calculations of the electronic structure of a set of naphthalene molecules with different functional groups (N, CN, NC, NH2, COH, COOH) adsorbed on Cu(111), with and without a Cu adatom. Our results show that while the interaction between the naphthalene backbone and the Cu(111) surface is dominated by van der Waals (vdW) forces, in all cases considered the functional group forms a covalent bond with the Cu (ad)atom (on) of the surface. The calculated differential charge redistribution shows that the strongest covalent bond is formed by the NC group, which differs remarkably from that formed by the CN group, while the vdW interaction is very similar in both cases. These results provide insights into the different surface coordination behavior of molecules with above-mentioned functional groups. Work support in part by NSF Grant CHE-1310327.

  2. Clickable SBA-15 to screen functional groups for adsorption of antibiotics.

    PubMed

    Gao, Jinsuo; Zhang, Xueying; Xu, Shutao; Liu, Jian; Tan, Feng; Li, Xinyong; Qu, Zhenping; Zhang, Yaobin; Quan, Xie

    2014-03-01

    Pharmaceutical antibiotics, as emerging contaminants, are usually composed of several functional groups that endow them with the ability to interact with adsorbents through different interactions. This makes the preparation of adsorbents tedious and time-consuming to screen appropriate functionalized materials. Herein, we describe the synthesis of clickable SBA-15 and demonstrate its feasibility as a screening material for the adsorption of antibiotics based on similar adsorption trends on materials with similar functional groups obtained by a click reaction and cocondensation/grafting methods.

  3. The Role of Reactive Functional Groups in Adhesive Bonding at the Aramid-Epoxy Interface.

    DTIC Science & Technology

    1986-09-15

    sta end ZIP CeO . 800 North Quincy Street i-q ?AiI 3 Arlington, VA 22217 " ae’Iv o. ’to. 6 -o. !The Role of Reactive Functional . . . 1 12. onsRonfaI...Unclassified SICUMI VY’V Ct.ASSiiICATyO OP ’T-S PAGE I Cont ... 11. The Role of Reactive Functional Groups in Adhesive Bonding at the Aramid-Epoxy...T-1 ROLE OF REACTIVE FUNCTIONAL GROUPS IN ADHESIVI 3ODI;G AT THE ARA fID-EPOXY INTIFA> BY L.S. PENN, T.J. BYERLEY, AND T.K. LIAO 1IDWEST RESEARCR

  4. GPU-based parallel group ICA for functional magnetic resonance data.

    PubMed

    Jing, Yanshan; Zeng, Weiming; Wang, Nizhuan; Ren, Tianlong; Shi, Yingchao; Yin, Jun; Xu, Qi

    2015-04-01

    The goal of our study is to develop a fast parallel implementation of group independent component analysis (ICA) for functional magnetic resonance imaging (fMRI) data using graphics processing units (GPU). Though ICA has become a standard method to identify brain functional connectivity of the fMRI data, it is computationally intensive, especially has a huge cost for the group data analysis. GPU with higher parallel computation power and lower cost are used for general purpose computing, which could contribute to fMRI data analysis significantly. In this study, a parallel group ICA (PGICA) on GPU, mainly consisting of GPU-based PCA using SVD and Infomax-ICA, is presented. In comparison to the serial group ICA, the proposed method demonstrated both significant speedup with 6-11 times and comparable accuracy of functional networks in our experiments. This proposed method is expected to perform the real-time post-processing for fMRI data analysis.

  5. Arrival order among native plant functional groups does not affect invasibility of constructed dune communities.

    PubMed

    Mason, T J; French, K; Jolley, D

    2013-10-01

    Different arrival order scenarios of native functional groups to a site may influence both resource use during development and final community structure. Arrival order may then indirectly influence community resistance to invasion. We present a mesocosm experiment of constructed coastal dune communities that monitored biotic and abiotic responses to different arrival orders of native functional groups. Constructed communities were compared with unplanted mesocosms. We then simulated a single invasion event by bitou (Chrysanthemoides monilifera ssp. rotundata), a dominant exotic shrub of coastal communities. We evaluated the hypothesis that plantings with simultaneous representation of grass, herb and shrub functional groups at the beginning of the experiment would more completely sequester resources and limit invasion than staggered plantings. Staggered plantings in turn would offer greater resource use and invasion resistance than unplanted mesocosms. Contrary to our expectations, there were few effects of arrival order on abiotic variables for the duration of the experiment and arrival order was unimportant in final community invasibility. All planted mesocosms supported significantly more invader germinants and significantly less invader abundance than unplanted mesocosms. Native functional group plantings may have a nurse effect during the invader germination and establishment phase and a competitive function during the invader juvenile and adult phase. Arrival order per se did not affect resource use and community invasibility in our mesocosm experiment. While grass, herb and shrub functional group plantings will not prevent invasion success in restored communities, they may limit final invader biomass.

  6. Identifying organic aerosol sources by comparing functional group composition in chamber and atmospheric particles.

    PubMed

    Russell, Lynn M; Bahadur, Ranjit; Ziemann, Paul J

    2011-03-01

    Measurements of submicron particles by Fourier transform infrared spectroscopy in 14 campaigns in North America, Asia, South America, and Europe were used to identify characteristic organic functional group compositions of fuel combustion, terrestrial vegetation, and ocean bubble bursting sources, each of which often accounts for more than a third of organic mass (OM), and some of which is secondary organic aerosol (SOA) from gas-phase precursors. The majority of the OM consists of alkane, carboxylic acid, hydroxyl, and carbonyl groups. The organic functional groups formed from combustion and vegetation emissions are similar to the secondary products identified in chamber studies. The near absence of carbonyl groups in the observed SOA associated with combustion is consistent with alkane rather than aromatic precursors, and the absence of organonitrate groups can be explained by their hydrolysis in humid ambient conditions. The remote forest observations have ratios of carboxylic acid, organic hydroxyl, and nonacid carbonyl groups similar to those observed for isoprene and monoterpene chamber studies, but in biogenic aerosols transported downwind of urban areas the formation of esters replaces the acid and hydroxyl groups and leaves only nonacid carbonyl groups. The carbonyl groups in SOA associated with vegetation emissions provides striking evidence for the mechanism of esterification as the pathway for possible oligomerization reactions in the atmosphere. Forest fires include biogenic emissions that produce SOA with organic components similar to isoprene and monoterpene chamber studies, also resulting in nonacid carbonyl groups in SOA.

  7. Structural shifts of aldehyde dehydrogenase enzymes were instrumental for the early evolution of retinoid-dependent axial patterning in metazoans

    PubMed Central

    Sobreira, Tiago J. P.; Marlétaz, Ferdinand; Simões-Costa, Marcos; Schechtman, Deborah; Pereira, Alexandre C.; Brunet, Frédéric; Sweeney, Sarah; Pani, Ariel; Aronowicz, Jochanan; Lowe, Christopher J.; Davidson, Bradley; Laudet, Vincent; Bronner, Marianne; de Oliveira, Paulo S. L.; Schubert, Michael; Xavier-Neto, José

    2011-01-01

    Aldehyde dehydrogenases (ALDHs) catabolize toxic aldehydes and process the vitamin A-derived retinaldehyde into retinoic acid (RA), a small diffusible molecule and a pivotal chordate morphogen. In this study, we combine phylogenetic, structural, genomic, and developmental gene expression analyses to examine the evolutionary origins of ALDH substrate preference. Structural modeling reveals that processing of small aldehydes, such as acetaldehyde, by ALDH2, versus large aldehydes, including retinaldehyde, by ALDH1A is associated with small versus large substrate entry channels (SECs), respectively. Moreover, we show that metazoan ALDH1s and ALDH2s are members of a single ALDH1/2 clade and that during evolution, eukaryote ALDH1/2s often switched between large and small SECs after gene duplication, transforming constricted channels into wide opened ones and vice versa. Ancestral sequence reconstructions suggest that during the evolutionary emergence of RA signaling, the ancestral, narrow-channeled metazoan ALDH1/2 gave rise to large ALDH1 channels capable of accommodating bulky aldehydes, such as retinaldehyde, supporting the view that retinoid-dependent signaling arose from ancestral cellular detoxification mechanisms. Our analyses also indicate that, on a more restricted evolutionary scale, ALDH1 duplicates from invertebrate chordates (amphioxus and ascidian tunicates) underwent switches to smaller and narrower SECs. When combined with alterations in gene expression, these switches led to neofunctionalization from ALDH1-like roles in embryonic patterning to systemic, ALDH2-like roles, suggesting functional shifts from signaling to detoxification. PMID:21169504

  8. Aminosilica materials as adsorbents for the selective removal of aldehydes and ketones from simulated bio-oil.

    PubMed

    Drese, Jeffrey H; Talley, Anne D; Jones, Christopher W

    2011-03-21

    The fast pyrolysis of biomass is a potential route to the production of liquid biorenewable fuel sources. However, degradation of the bio-oil mixtures due to reaction of oxygenates, such as aldehydes and ketones, reduces the stability of the liquids and can impact long-term storage and shipping. Herein, solid aminosilica adsorbents are described for the selective adsorptive removal of reactive aldehyde and ketone species. Three aminosilica adsorbents are prepared through the reaction of amine-containing silanes with pore-expanded mesoporous silica. A fourth aminosilica adsorbent is prepared through the ring-opening polymerization of aziridine from pore-expanded mesoporous silica. Adsorption experiments with a representative mixture of bio-oil model compounds are presented using each adsorbent at room temperature and 45 °C. The adsorbent comprising only primary amines adsorbs the largest amount of aldehydes and ketones. The overall reactivity of this adsorbent increases with increasing temperature. Additional aldehyde screening experiments show that the reactivity of aldehydes with aminosilicas varies depending on their chemical functionality. Initial attempts to regenerate an aminosilica adsorbent by acid hydrolysis show that they can be at least partially regenerated for further use.

  9. Synergistic effect between defect sites and functional groups on the hydrolysis of cellulose over activated carbon.

    PubMed

    Foo, Guo Shiou; Sievers, Carsten

    2015-02-01

    The chemical oxidation of activated carbon by H2 O2 and H2 SO4 is investigated, structural and chemical modifications are characterized, and the materials are used as catalysts for the hydrolysis of cellulose. Treatment with H2 O2 enlarges the pore size and imparts functional groups such as phenols, lactones, and carboxylic acids. H2 SO4 treatment targets the edges of carbon sheets primarily, and this effect is more pronounced with a higher temperature. Adsorption isotherms demonstrate that the adsorption of oligomers on functionalized carbon is dominated by van der Waals forces. The materials treated chemically are active for the hydrolysis of cellulose despite the relative weakness of most of their acid sites. It is proposed that a synergistic effect between defect sites and functional groups enhances the activity by inducing a conformational change in the glucan chains if they are adsorbed at defect sites. This activates the glycosidic bonds for hydrolysis by in-plane functional groups.

  10. Human liver aldehyde dehydrogenase: coenzyme binding

    SciTech Connect

    Kosley, L.L.; Pietruszko, R.

    1987-05-01

    The binding of (U-/sup 14/C) NAD to mitochondrial (E2) and cytoplasmin(E1) aldehyde dehydrogenase was measured by gel filtration and sedimentation techniques. The binding data for NAD and (E1) yielded linear Scatchard plots giving a dissociation constant of 25 (+/- 8) uM and the stoichiometry of 2 mol of NAD bound per mol of E1. The binding data for NAD and (E2) gave nonlinear Scatchard plots. The binding of NADH to E2 was measured via fluorescence enhancement; this could not be done with E1 because there was no signal. The dissociation constant for E2 by this technique was 0.7 (+/- 0.4) uM and stoichiometry of 1.0 was obtained. The binding of (U-/sup 14/C) NADH to (E1) and (E2) was also measured by the sedimentation technique. The binding data for (E1) and NADH gave linear Scatchard plots giving a dissociation constant of 13 (+/- 6) uM and the stoichiometry of 2.0. The binding data for NADH to (E2) gave nonlinear Scatchard plots. With (E1), the dissociation constants for both NAD and NADH are similar to those determined kinetically, but the stoichiometry is only half of that found by stopped flow technique. With (E2) the dissociation constant by fluorometric procedure was 2 orders of magnitude less than that from catalytic reaction.

  11. Molecular Structure and Reactivity in the Pyrolysis of Aldehydes

    NASA Astrophysics Data System (ADS)

    Sias, Eric; Cole, Sarah; Sowards, John; Warner, Brian; Wright, Emily; McCunn, Laura R.

    2016-06-01

    The effect of alkyl chain structure on pyrolysis mechanisms has been investigated in a series of aldehydes. Isovaleraldehyde, CH_3CH(CH_3)CH_2CHO, and pivaldehyde, (CH_3)_3CCHO, were subject to thermal decomposition in a resistively heated SiC tubular reactor at 800-1200 °C. Matrix-isolation FTIR spectroscopy was used to identify pyrolysis products. Carbon monoxide and isobutene were major products from each of the aldehydes, which is consistent with what is known from previous studies of unbranched alkyl-chain aldehydes. Other products observed include vinyl alcohol, propene, acetylene, and ethylene, revealing complexities to be considered in the pyrolysis of large, branched-chain aldehydes.

  12. A kinetic estimate of the free aldehyde content of aldoses

    NASA Technical Reports Server (NTRS)

    Dworkin, J. P.; Miller, S. L.; Bada, J. L. (Principal Investigator)

    2000-01-01

    The relative free aldehyde content of eight hexoses and four pentoses has been estimated within about 10% from the rate constants for their reaction with urazole (1,2,4-triazole-3,5-dione). These values of the percent free aldehyde are in agreement with those estimated from CD measurements, but are more accurate. The relative free aldehyde contents for the aldoses were then correlated to various literature NMR measurements to obtain the absolute values. This procedure was also done for three deoxyaldoses, which react much more rapidly than can be accounted for by the free aldehyde content. This difference in reactivity between aldoses and deoxyaldoses is due to the inductive effect of the H versus the OH on C-2'. This may help explain why deoxyribonucleosides hydrolyze much more rapidly than ribonucleosides.

  13. Silver-catalyzed synthesis of amides from amines and aldehydes

    DOEpatents

    Madix, Robert J; Zhou, Ling; Xu, Bingjun; Friend, Cynthia M; Freyschlag, Cassandra G

    2014-11-18

    The invention provides a method for producing amides via the reaction of aldehydes and amines with oxygen adsorbed on a metallic silver or silver alloy catalyst. An exemplary reaction is shown in Scheme 1: (I), (II), (III). ##STR00001##

  14. An integrated QSAR-PBK/D modelling approach for predicting detoxification and DNA adduct formation of 18 acyclic food-borne α,β-unsaturated aldehydes

    SciTech Connect

    Kiwamoto, R. Spenkelink, A.; Rietjens, I.M.C.M.; Punt, A.

    2015-01-01

    Acyclic α,β-unsaturated aldehydes present in food raise a concern because the α,β-unsaturated aldehyde moiety is considered a structural alert for genotoxicity. However, controversy remains on whether in vivo at realistic dietary exposure DNA adduct formation is significant. The aim of the present study was to develop physiologically based kinetic/dynamic (PBK/D) models to examine dose-dependent detoxification and DNA adduct formation of a group of 18 food-borne acyclic α,β-unsaturated aldehydes without 2- or 3-alkylation, and with no more than one conjugated double bond. Parameters for the PBK/D models were obtained using quantitative structure–activity relationships (QSARs) defined with a training set of six selected aldehydes. Using the QSARs, PBK/D models for the other 12 aldehydes were defined. Results revealed that DNA adduct formation in the liver increases with decreasing bulkiness of the molecule especially due to less efficient detoxification. 2-Propenal (acrolein) was identified to induce the highest DNA adduct levels. At realistic dietary intake, the predicted DNA adduct levels for all aldehydes were two orders of magnitude lower than endogenous background levels observed in disease free human liver, suggesting that for all 18 aldehydes DNA adduct formation is negligible at the relevant levels of dietary intake. The present study provides a proof of principle for the use of QSAR-based PBK/D modelling to facilitate group evaluations and read-across in risk assessment. - Highlights: • Physiologically based in silico models were made for 18 α,β-unsaturated aldehydes. • Kinetic parameters were determined by in vitro incubations and a QSAR approach. • DNA adduct formation was negligible at levels relevant for dietary intake. • The use of QSAR-based PBK/D modelling facilitates group evaluations and read-across.

  15. Driving factors of the phytoplankton functional groups in a deep Mediterranean reservoir.

    PubMed

    Becker, Vanessa; Caputo, Luciano; Ordóñez, Jaime; Marcé, Rafael; Armengol, Joan; Crossetti, Luciane O; Huszar, Vera L M

    2010-06-01

    The control of phytoplankton growth is mainly related to the availability of light and nutrients. Both may select phytoplankton species, but only if they occur in limiting amounts. During the last decade, the functional groups approach, based on the physiological, morphological and ecological attributes of the species, has proved to be a more efficient way to analyze seasonal changes in phytoplankton biomass. We analysed the dynamics of the phytoplankton functional groups sensu Reynolds, recognising the driving forces (light, mixing regime, and nutrients) in the Sau Reservoir, based on a one-year cycle (monthly surface-water sampling). The Sau Reservoir is a Mediterranean water-supply reservoir with a canyon-shaped basin and a clear and mixed epilimnion layer. The long stratification period and high light availability led to high phytoplankton biomass (110.8 fresh-weight mg L(-1)) in the epilimnion during summer. The reservoir showed P-limitation for phytoplankton growth in this period. All functional groups included one or more species (X2-Rhodomonas spp.; Y-Cryptomonas spp.; F-Oocystis lacustris; K-Aphanocapsa spp.) selected by resources, especially phosphorus. Species of Cryptomonas (group Y) dominated during the mixing period (winter season) in conditions of low light and relatively high availability of dissolved nutrients. Increases in water-column stability during spring stratification led to phytoplankton biomass increases due to the dominance of small flagellate functional groups (X2 and X3, chrysophyceans). The colonial chlorophycean O. lacustris (group F) peaked during the mid-summer stratification, when the mixed epilimnion was clearly depleted in nutrients, especially SRP. High temperature and increases in nutrient concentration during the end-summer and mid-autumn resulted in a decrease of green algae (group F) and increase of Aphanocapsa spp. (cyanobacteria, group K) and dinoflagellates (group L(o)). The study also revealed the important role of

  16. In-medium spectral functions of vector- and axial-vector mesons from the functional renormalization group

    NASA Astrophysics Data System (ADS)

    Jung, Christopher; Rennecke, Fabian; Tripolt, Ralf-Arno; von Smekal, Lorenz; Wambach, Jochen

    2017-02-01

    In this work, we present the first results on vector- and axial-vector meson spectral functions as obtained by applying the nonperturbative functional renormalization group approach to an effective low-energy theory motivated by the gauged linear sigma model. By using a recently proposed analytic continuation method, we study the in-medium behavior of the spectral functions of the ρ and a1 mesons in different regimes of the phase diagram. In particular, we demonstrate explicitly how these spectral functions degenerate at high temperatures as well as at large chemical potentials, as a consequence of the restoration of chiral symmetry. In addition, we also compute the momentum dependence of the ρ and a1 spectral functions and discuss the various timelike and spacelike processes that can occur.

  17. Modeling phytoplankton community in reservoirs. A comparison between taxonomic and functional groups-based models.

    PubMed

    Di Maggio, Jimena; Fernández, Carolina; Parodi, Elisa R; Diaz, M Soledad; Estrada, Vanina

    2016-01-01

    In this paper we address the formulation of two mechanistic water quality models that differ in the way the phytoplankton community is described. We carry out parameter estimation subject to differential-algebraic constraints and validation for each model and comparison between models performance. The first approach aggregates phytoplankton species based on their phylogenetic characteristics (Taxonomic group model) and the second one, on their morpho-functional properties following Reynolds' classification (Functional group model). The latter approach takes into account tolerance and sensitivity to environmental conditions. The constrained parameter estimation problems are formulated within an equation oriented framework, with a maximum likelihood objective function. The study site is Paso de las Piedras Reservoir (Argentina), which supplies water for consumption for 450,000 population. Numerical results show that phytoplankton morpho-functional groups more closely represent each species growth requirements within the group. Each model performance is quantitatively assessed by three diagnostic measures. Parameter estimation results for seasonal dynamics of the phytoplankton community and main biogeochemical variables for a one-year time horizon are presented and compared for both models, showing the functional group model enhanced performance. Finally, we explore increasing nutrient loading scenarios and predict their effect on phytoplankton dynamics throughout a one-year time horizon.

  18. Local and Regional Determinants of an Uncommon Functional Group in Freshwater Lakes and Ponds

    PubMed Central

    McCann, Michael James

    2015-01-01

    A combination of local and regional factors and stochastic forces is expected to determine the occurrence of species and the structure of communities. However, in most cases, our understanding is incomplete, with large amounts of unexplained variation. Using functional groups rather than individual species may help explain the relationship between community composition and conditions. In this study, I used survey data from freshwater lakes and ponds to understand factors that determine the presence of the floating plant functional group in the northeast United States. Of the 176 water bodies surveyed, 104 (59.1%) did not contain any floating plant species. The occurrence of this functional group was largely determined by local abiotic conditions, which were spatially autocorrelated across the region. A model predicting the presence of the floating plant functional group performed similarly to the best species-specific models. Using a permutation test, I also found that the observed prevalence of floating plants is no different than expected by random assembly from a species pool of its size. These results suggest that the size of the species pool interacts with local conditions in determining the presence of a functional group. Nevertheless, a large amount of unexplained variation remains, attributable to either stochastic species occurrence or incomplete predictive models. The simple permutation approach in this study can be extended to test alternative models of community assembly. PMID:26121636

  19. The dual roles of functional groups in the photoluminescence of graphene quantum dots.

    PubMed

    Wang, Shujun; Cole, Ivan S; Zhao, Dongyuan; Li, Qin

    2016-04-14

    The photoluminescent properties of graphene nanoparticle (named graphene quantum dots) have attracted significant research attention in recent years owing to their profound application potential. However, the photoluminescence (PL) origin of this class of nanocarbons is still unclear. In this paper, combining direct experimental evidence enabled by a facile size-tunable oxygenated graphene quantum dots (GQDs) synthesis method and theoretical calculations, the roles of the aromatic core, functional groups and disordered structures (i.e. defects and sp(3) carbon) in the PL of oxygenated GQDs are elucidated in detail. In particular, we found that the functional groups on GQDs play dual roles in the overall emission: (1) they enable π* → n and σ* → n transitions, resulting in a molecular type of PL, spectrally invariable with change of particle size or excitation energy; (2) similar to defects and sp(3) carbon, functional groups also induce structural deformation to the aromatic core, leading to mid-gap states or, in other words, energy traps, causing π* → mid-gap states → π transitions. Therefore, functional groups contribute to both the blue edge and the red shoulder of GQDs' PL spectra. The new insights on the role of functional groups in PL of fluorescent nanocarbons will enable better designs of this new class of materials.

  20. Anti-Biofilm Activity of a Long-Chain Fatty Aldehyde from Antarctic Pseudoalteromonas haloplanktis TAC125 against Staphylococcus epidermidis Biofilm.

    PubMed

    Casillo, Angela; Papa, Rosanna; Ricciardelli, Annarita; Sannino, Filomena; Ziaco, Marcello; Tilotta, Marco; Selan, Laura; Marino, Gennaro; Corsaro, Maria M; Tutino, Maria L; Artini, Marco; Parrilli, Ermenegilda

    2017-01-01

    Staphylococcus epidermidis is a harmless human skin colonizer responsible for ~20% of orthopedic device-related infections due to its capability to form biofilm. Nowadays there is an interest in the development of anti-biofilm molecules. Marine bacteria represent a still underexploited source of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. Previous results have demonstrated that the culture supernatant of Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 impairs the formation of S. epidermidis biofilm. Further, evidence supports the hydrophobic nature of the active molecule, which has been suggested to act as a signal molecule. In this paper we describe an efficient activity-guided purification protocol which allowed us to purify this anti-biofilm molecule and structurally characterize it by NMR and mass spectrometry analyses. Our results demonstrate that the anti-biofilm molecule is pentadecanal, a long-chain fatty aldehyde, whose anti-S. epidermidis biofilm activity has been assessed using both static and dynamic biofilm assays. The specificity of its action on S. epidermidis biofilm has been demonstrated by testing chemical analogs of pentadecanal differing either in the length of the aliphatic chain or in their functional group properties. Further, indications of the mode of action of pentadecanal have been collected by studying the bioluminescence of a Vibrio harveyi reporter strain for the detection of autoinducer AI-2 like activities. The data collected suggest that pentadecanal acts as an AI-2 signal. Moreover, the aldehyde metabolic role and synthesis in the Antarctic source strain has been investigated. To the best of our knowledge, this is the first report on the identification of an anti-biofilm molecule form from cold-adapted bacteria and on the action of a long-chain fatty aldehyde acting as an anti-biofilm molecule against S. epidermidis.

  1. Anti-Biofilm Activity of a Long-Chain Fatty Aldehyde from Antarctic Pseudoalteromonas haloplanktis TAC125 against Staphylococcus epidermidis Biofilm

    PubMed Central

    Casillo, Angela; Papa, Rosanna; Ricciardelli, Annarita; Sannino, Filomena; Ziaco, Marcello; Tilotta, Marco; Selan, Laura; Marino, Gennaro; Corsaro, Maria M.; Tutino, Maria L.; Artini, Marco; Parrilli, Ermenegilda

    2017-01-01

    Staphylococcus epidermidis is a harmless human skin colonizer responsible for ~20% of orthopedic device-related infections due to its capability to form biofilm. Nowadays there is an interest in the development of anti-biofilm molecules. Marine bacteria represent a still underexploited source of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. Previous results have demonstrated that the culture supernatant of Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 impairs the formation of S. epidermidis biofilm. Further, evidence supports the hydrophobic nature of the active molecule, which has been suggested to act as a signal molecule. In this paper we describe an efficient activity-guided purification protocol which allowed us to purify this anti-biofilm molecule and structurally characterize it by NMR and mass spectrometry analyses. Our results demonstrate that the anti-biofilm molecule is pentadecanal, a long-chain fatty aldehyde, whose anti-S. epidermidis biofilm activity has been assessed using both static and dynamic biofilm assays. The specificity of its action on S. epidermidis biofilm has been demonstrated by testing chemical analogs of pentadecanal differing either in the length of the aliphatic chain or in their functional group properties. Further, indications of the mode of action of pentadecanal have been collected by studying the bioluminescence of a Vibrio harveyi reporter strain for the detection of autoinducer AI-2 like activities. The data collected suggest that pentadecanal acts as an AI-2 signal. Moreover, the aldehyde metabolic role and synthesis in the Antarctic source strain has been investigated. To the best of our knowledge, this is the first report on the identification of an anti-biofilm molecule form from cold-adapted bacteria and on the action of a long-chain fatty aldehyde acting as an anti-biofilm molecule against S. epidermidis. PMID:28280714

  2. Effects of chemical functional groups on elemental mercury adsorption on carbonaceous surfaces.

    PubMed

    Liu, Jing; Cheney, Marcos A; Wu, Fan; Li, Meng

    2011-02-15

    A systematic theoretical study using density functional theory is performed to provide molecular-level understanding of the effects of chemical functional groups on mercury adsorption on carbonaceous surfaces. The zigzag and armchair edges were used in modeling the carbonaceous surfaces to simulate different adsorption sites. The edge atoms on the upper side of the models are unsaturated to simulate active sites. All calculations (optimizations, energies, and frequencies) were made at B3PW91 density functional theory level, using RCEP60VDZ basis set for mercury and 6-31G(d) pople basis set for other atoms. The results indicate that the embedding of halogen atom can increase the activity of its neighboring site which in turn increases the adsorption capacity of the carbonaceous surface for Hg(0). The adsorption belongs to chemisorptions, which is in good agreement with the experimental results. For the effects of oxygen functional groups, lactone, carbonyl and semiquinone favor Hg(0) adsorption because they increase the neighboring site's activity for mercury adsorption. On the contrary, phenol and carboxyl functional groups show a physisorption of Hg(0), and reduce Hg capture. This result can explain the seemingly conflicting experimental results reported in the literature concerning the influence of oxygen functional groups on mercury adsorption on carbonaceous surface.

  3. Slow-binding inhibitors of prolyl oligopeptidase with different functional groups at the P1 site.

    PubMed

    Venäläinen, Jarkko I; Juvonen, Risto O; Garcia-Horsman, J Arturo; Wallén, Erik A A; Christiaans, Johannes A M; Jarho, Elina M; Gynther, Jukka; Männistö, Pekka T

    2004-09-15

    POP (prolyl oligopeptidase) specifically hydrolyses a number of small proline-containing peptides at the carboxy end of the proline residue and POP inhibitors have been shown to have cognition-enhancing properties. It has been noted that certain functional groups at the P1 site of the inhibitor, which correspond to the substrate residue on the N-terminal side of the bond to be cleaved, increase the inhibitory potency. However, detailed mechanistic and kinetic analysis of the inhibition has not been studied. In the present study, we examined the effect of different functional groups at the P1 site of the parent inhibitor isophthalic acid bis-(L-prolylpyrrolidine) amide on the binding kinetics to POP. Addition of CHO, CN or COCH(2)OH groups to the P1 site increased the inhibitory potency by two orders of magnitude (K(i)=11.8-0.1 nM) and caused a clear slow-binding inhibition. The inhibitor containing a CHO group had the lowest association rate constant, k(on)=(2.43+/-0.12) x 10(5) M(-1) x s(-1), whereas the inhibitor with a CN group exhibited the fastest binding, k(on)=(12.0+/-0.08)x10(5) M(-1) x s(-1). In addition, the dissociation rate was found to be crucially dependent on the type of the functional group. Compounds with COCH(2)OH and CHO groups had much longer half-lives of dissociation (over 5 h) compared with the compound with the CN group (25 min), although the K(i) values of the compounds were relatively similar. A possibility to optimize the duration of inhibition by changing the functional group at the P1 site is important when planning therapeutically useful POP inhibitors.

  4. Nitric Oxide Mediates the Stress Response Induced by Diatom Aldehydes in the Sea Urchin Paracentrotus lividus

    PubMed Central

    Romano, Giovanna; Costantini, Maria; Buttino, Isabella; Ianora, Adrianna; Palumbo, Anna

    2011-01-01

    Diatoms are ubiquitous and abundant primary producers that have been traditionally considered as a beneficial food source for grazers and for the transfer of carbon through marine food webs. However, many diatom species produce polyunsaturated aldehydes that disrupt development in the offspring of grazers that feed on these unicellular algae. Here we provide evidence that production of the physiological messenger nitric oxide increases after treatment with the polyunsaturated aldehyde decadienal in embryos of the sea urchin Paracentrotus lividus. At high decadienal concentrations, nitric oxide mediates initial apoptotic events leading to loss of mitochondrial functionality through the generation of peroxynitrite. At low decadienal concentrations, nitric oxide contributes to the activation of hsp70 gene expression thereby protecting embryos against the toxic effects of this aldehyde. When nitric oxide levels were lowered by inhibiting nitric oxide synthase activity, the expression of hsp70 in swimming blastula decreased and the proportion of abnormal plutei increased. However, in later pluteus stages nitric oxide was no longer able to exert this protective function: hsp70 and nitric oxide synthase expression decreased with a consequent increase in the expression of caspase-8. Our findings that nitric oxide production increases rapidly in response to a toxic exogenous stimulus opens new perspectives on the possible role of this gas as an important messenger to environmental stress in sea urchins and for understanding the cellular mechanisms underlying toxicity during diatom blooms. PMID:22022485

  5. Nitric oxide mediates the stress response induced by diatom aldehydes in the sea urchin Paracentrotus lividus.

    PubMed

    Romano, Giovanna; Costantini, Maria; Buttino, Isabella; Ianora, Adrianna; Palumbo, Anna

    2011-01-01

    Diatoms are ubiquitous and abundant primary producers that have been traditionally considered as a beneficial food source for grazers and for the transfer of carbon through marine food webs. However, many diatom species produce polyunsaturated aldehydes that disrupt development in the offspring of grazers that feed on these unicellular algae. Here we provide evidence that production of the physiological messenger nitric oxide increases after treatment with the polyunsaturated aldehyde decadienal in embryos of the sea urchin Paracentrotus lividus. At high decadienal concentrations, nitric oxide mediates initial apoptotic events leading to loss of mitochondrial functionality through the generation of peroxynitrite. At low decadienal concentrations, nitric oxide contributes to the activation of hsp70 gene expression thereby protecting embryos against the toxic effects of this aldehyde. When nitric oxide levels were lowered by inhibiting nitric oxide synthase activity, the expression of hsp70 in swimming blastula decreased and the proportion of abnormal plutei increased. However, in later pluteus stages nitric oxide was no longer able to exert this protective function: hsp70 and nitric oxide synthase expression decreased with a consequent increase in the expression of caspase-8. Our findings that nitric oxide production increases rapidly in response to a toxic exogenous stimulus opens new perspectives on the possible role of this gas as an important messenger to environmental stress in sea urchins and for understanding the cellular mechanisms underlying toxicity during diatom blooms.

  6. Glass transition of polystyrene (PS) studied by Raman spectroscopic investigation of its phenyl functional groups

    NASA Astrophysics Data System (ADS)

    Bertoldo Menezes, D.; Reyer, A.; Marletta, A.; Musso, M.

    2017-01-01

    In polymeric materials the glass transition (GT) is a well-known and very important relaxation process related to movements of functional groups in the polymeric chain. In this work, we show the potential of Raman spectroscopy for exploring the GT process in the polymer polystyrene. We collected Raman spectra during a step-by-step heating process of the sample, which allowed us to collect signatures of the GT process from peak parameters of specific vibrational modes, and to verify the GT temperature. Results of the latter were in accordance with published values obtained via other methods. We identified the aromatic ring vibrational modes of the phenyl functional groups to be those which, due to steric hindrance, suffer the largest influence during the GT process. This confirms that Raman spectroscopy can be used as a complementary technique to perform GT investigations in polymeric materials due to its sensitivity to small intermolecular changes affecting vibrational properties of relevant functional side groups.

  7. Wigner functions for noncommutative quantum mechanics: A group representation based construction

    NASA Astrophysics Data System (ADS)

    Chowdhury, S. Hasibul Hassan; Ali, S. Twareque

    2015-12-01

    This paper is devoted to the construction and analysis of the Wigner functions for noncommutative quantum mechanics, their marginal distributions, and star-products, following a technique developed earlier, viz, using the unitary irreducible representations of the group GNC, which is the three fold central extension of the Abelian group of ℝ4. These representations have been exhaustively studied in earlier papers. The group GNC is identified with the kinematical symmetry group of noncommutative quantum mechanics of a system with two degrees of freedom. The Wigner functions studied here reflect different levels of non-commutativity—both the operators of position and those of momentum not commuting, the position operators not commuting and finally, the case of standard quantum mechanics, obeying the canonical commutation relations only.

  8. Wigner functions for noncommutative quantum mechanics: A group representation based construction

    SciTech Connect

    Chowdhury, S. Hasibul Hassan; Ali, S. Twareque

    2015-12-15

    This paper is devoted to the construction and analysis of the Wigner functions for noncommutative quantum mechanics, their marginal distributions, and star-products, following a technique developed earlier, viz, using the unitary irreducible representations of the group G{sub NC}, which is the three fold central extension of the Abelian group of ℝ{sup 4}. These representations have been exhaustively studied in earlier papers. The group G{sub NC} is identified with the kinematical symmetry group of noncommutative quantum mechanics of a system with two degrees of freedom. The Wigner functions studied here reflect different levels of non-commutativity—both the operators of position and those of momentum not commuting, the position operators not commuting and finally, the case of standard quantum mechanics, obeying the canonical commutation relations only.

  9. Reactive ring-opened aldehyde metabolites in benzene hematotoxicity.

    PubMed Central

    Witz, G; Zhang, Z; Goldstein, B D

    1996-01-01

    The hematotoxicity of benzene is mediated by reactive benzene metabolites and possibly by other intermediates including reactive oxygen species. We previously hypothesized that ring-opened metabolites may significantly contribute to benzene hematotoxicity. Consistent with this hypothesis, our studies initially demonstrated that benzene is metabolized in vitro to trans-trans-muconaldehyde (MUC), a reactive six-carbon diene dialdehyde, and that MUC is toxic to the bone marrow in a manner similar to benzene. Benzene toxicity most likely involves interactions among several metabolites that operate by different mechanisms to produce more than one biological effect. Our studies indicate that MUC coadministered with hydroquinone is a particularly potent metabolite combination that causes bone marrow damage, suggesting that the involvement of ring-opened metabolites in benzene toxicity may be related to their biological effects in combination with other benzene metabolites. Studies in our laboratory and by others indicate that MUC is metabolized to a variety of compounds by oxidation or reduction of the aldehyde groups. The aldehydic MUC metabolite 6-hydroxy-trans-trans-2,4-hexadienal (CHO-M-OH), similar to MUC but to a lesser extent, is reactive toward glutathione, mutagenic in V79 cells, and hematotoxic in mice. It is formed by monoreduction of MUC, a process that is reversible and could be of biological significance in benzene bone marrow toxicity. The MUC metabolite 6-hydroxy-trans-trans-2,4-hexadienoic (COOH-M-OH) is an end product of MUC metabolism in vitro. Our studies indicate that COOH-M-OH is a urinary metabolite of benzene in mice, a finding that provides further indirect evidence for the in vivo formation of MUC from benzene. Mechanistic studies showed the formation of cis-trans-muconaldehyde in addition to MUC from benzene incubated in a hydroxyl radical-generating Fenton system. These results suggest that the benzene ring is initially opened to cis

  10. Functional grouping and cortical–subcortical interactions in emotion: A meta-analysis of neuroimaging studies

    PubMed Central

    Kober, Hedy; Barrett, Lisa Feldman; Joseph, Josh; Bliss-Moreau, Eliza; Lindquist, Kristen; Wager, Tor D.

    2009-01-01

    We performed an updated quantitative meta-analysis of 162 neuroimaging studies of emotion using a novel multi-level kernel-based approach, focusing on locating brain regions consistently activated in emotional tasks and their functional organization into distributed functional groups, independent of semantically defined emotion category labels (e.g., “anger,” “fear”). Such brain-based analyses are critical if our ways of labeling emotions are to be evaluated and revised based on consistency with brain data. Consistent activations were limited to specific cortical sub-regions, including multiple functional areas within medial, orbital, and inferior lateral frontal cortices. Consistent with a wealth of animal literature, multiple subcortical activations were identified, including amygdala, ventral striatum, thalamus, hypothalamus, and periaqueductal gray. We used multivariate parcellation and clustering techniques to identify groups of co-activated brain regions across studies. These analyses identified six distributed functional groups, including medial and lateral frontal groups, two posterior cortical groups, and paralimbic and core limbic/brainstem groups. These functional groups provide information on potential organization of brain regions into large-scale networks. Specific follow-up analyses focused on amygdala, periaqueductal gray (PAG), and hypothalamic (Hy) activations, and identified frontal cortical areas co-activated with these core limbic structures. While multiple areas of frontal cortex co-activated with amygdala sub-regions, a specific region of dorsomedial prefrontal cortex (dmPFC, Brodmann’s Area 9/32) was the only area co-activated with both PAG and Hy. Subsequent mediation analyses were consistent with a pathway from dmPFC through PAG to Hy. These results suggest that medial frontal areas are more closely associated with core limbic activation than their lateral counterparts, and that dmPFC may play a particularly important role in the

  11. Functional network organizations of two contrasting temperament groups in dimensions of novelty seeking and harm avoidance.

    PubMed

    Kyeong, Sunghyon; Kim, Eunjoo; Park, Hae-Jeong; Hwang, Dong-Uk

    2014-08-05

    Novelty seeking (NS) and harm avoidance (HA) are two major dimensions of temperament in Cloninger׳s neurobiological model of personality. Previous neurofunctional and biological studies on temperament dimensions of HA and NS suggested that the temperamental traits have significant correlations with cortical and subcortical brain regions. However, no study to date has investigated the functional network modular organization as a function of the temperament dimension. The temperament dimensions were originally proposed to be independent of one another. However, a meta-analysis based on 16 published articles found a significant negative correlation between HA and NS (Miettunen et al., 2008). Based on this negative correlation, the current study revealed the whole-brain connectivity modular architecture for two contrasting temperament groups. The k-means clustering algorithm, with the temperamental traits of HA and NS as an input, was applied to divide the 40 subjects into two temperament groups: 'high HA and low NS' versus 'low HA and high NS'. Using the graph theoretical framework, we found a functional segregation of whole brain network architectures derived from resting-state functional MRI. In the 'high HA and low NS' group, the regulatory brain regions, such as the prefrontal cortex (PFC), are clustered together with the limbic system. In the 'low HA and high NS' group, however, brain regions lying on the dopaminergic pathways, such as the PFC and basal ganglia, are partitioned together. These findings suggest that the neural basis of inhibited, passive, and inactive behaviors in the 'high HA and low NS' group was derived from the increased network associations between the PFC and limbic clusters. In addition, supporting evidence of topological differences between the two temperament groups was found by analyzing the functional connectivity density and gray matter volume, and by computing the relationships between the morphometry and function of the brain.

  12. Hydrological-niche models predict water plant functional group distributions in diverse wetland types.

    PubMed

    Deane, David C; Nicol, Jason M; Gehrig, Susan L; Harding, Claire; Aldridge, Kane T; Goodman, Abigail M; Brookes, Justin D

    2017-03-06

    Human use of water resources threatens environmental water supplies. If resource managers are to develop policies that avoid unacceptable ecological impacts, some means to predict ecosystem response to changes in water availability is necessary. This is difficult to achieve at spatial-scales relevant for water resource management because of the high natural variability in ecosystem hydrology and ecology. Water plant functional groups classify species with similar hydrological niche preferences together, allowing a qualitative means to generalise community responses to changes in hydrology. We tested the potential for functional groups in making quantitative prediction of water-plant-functional-group distributions across diverse wetland types over a large geographical extent. We sampled wetlands covering a broad range of hydrogeomorphic and salinity conditions in South Australia, collecting both hydrological and floristic data from 697 quadrats across 28 wetland hydrological gradients. We built hydrological-niche models for eight water plant functional groups using a range of candidate models combining different surface inundation metrics. We then tested the predictive performance of top-ranked individual and averaged models for each functional group. Cross validation showed models achieved acceptable predictive performance, with correct classification rates in the range 0.68 - 0.95. Model predictions can be made at any spatial scale that hydrological data are available and could be implemented in a geographical information system. We show the response of water plant functional groups to inundation is consistent enough across diverse wetland types to quantify the probability of hydrological impacts over regional spatial scales. This article is protected by copyright. All rights reserved.

  13. Protection and deprotection approach for the introduction of functional groups into metal-organic frameworks.

    PubMed

    Yamada, Teppei; Kitagawa, Hiroshi

    2009-05-13

    A noncoordinating hydroxyl group was introduced into a metal-organic framework (MOF) by a procedure involving a protection, complexation, and deprotection (PCD) reaction sequence, and the crystal structure of a novel MOF, [Zn(dhybdc)(bpy)] x 4 DMF (1), was determined. 1 did not have an interpenetrated structure. The three-dimensional pores had large apertures. Results showed that the PCD method is a novel synthetic method for the introduction of various functional groups into MOFs.

  14. Testing Group Differences in Brain Functional Connectivity: Using Correlations or Partial Correlations?

    PubMed Central

    Kim, Junghi; Wozniak, Jeffrey R.; Mueller, Bryon A.

    2015-01-01

    Abstract Resting-state functional magnetic resonance imaging allows one to study brain functional connectivity, partly motivated by evidence that patients with complex disorders, such as Alzheimer's disease, may have altered functional brain connectivity patterns as compared with healthy subjects. A functional connectivity network describes statistical associations of the neural activities among distinct and distant brain regions. Recently, there is a major interest in group-level functional network analysis; however, there is a relative lack of studies on statistical inference, such as significance testing for group comparisons. In particular, it is still debatable which statistic should be used to measure pairwise associations as the connectivity weights. Many functional connectivity studies have used either (full or marginal) correlations or partial correlations for pairwise associations. This article investigates the performance of using either correlations or partial correlations for testing group differences in brain connectivity, and how sparsity levels and topological structures of the connectivity would influence statistical power to detect group differences. Our results suggest that, in general, testing group differences in networks deviates from estimating networks. For example, high regularization in both covariance matrices and precision matrices may lead to higher statistical power; in particular, optimally selected regularization (e.g., by cross-validation or even at the true sparsity level) on the precision matrices with small estimation errors may have low power. Most importantly, and perhaps surprisingly, using either correlations or partial correlations may give very different testing results, depending on which of the covariance matrices and the precision matrices are sparse. Specifically, if the precision matrices are sparse, presumably and arguably a reasonable assumption, then using correlations often yields much higher powered and more

  15. Water Contact Angle Dependence with Hydroxyl Functional Groups on Silica Surfaces under CO2 Sequestration Conditions.

    PubMed

    Chen, Cong; Zhang, Ning; Li, Weizhong; Song, Yongchen

    2015-12-15

    Functional groups on silica surfaces under CO2 sequestration conditions are complex due to reactions among supercritical CO2, brine and silica. Molecular dynamics simulations have been performed to investigate the effects of hydroxyl functional groups on wettability. It has been found that wettability shows a strong dependence on functional groups on silica surfaces: silanol number density, space distribution, and deprotonation/protonation degree. For neutral silica surfaces with crystalline structure (Q(3), Q(3)/Q(4), Q(4)), as silanol number density decreases, contact angle increases from 33.5° to 146.7° at 10.5 MPa and 318 K. When Q(3) surface changes to an amorphous structure, water contact angle increases 20°. Water contact angle decreases about 12° when 9% of silanol groups on Q(3) surface are deprotonated. When the deprotonation degree increases to 50%, water contact angle decreases to 0. The dependence of wettability on silica surface functional groups was used to analyze contact angle measurement ambiguity in literature. The composition of silica surfaces is complicated under CO2 sequestration conditions, the results found in this study may help to better understand wettability of CO2/brine/silica system.

  16. A novel joint sparse partial correlation method for estimating group functional networks.

    PubMed

    Liang, Xiaoyun; Connelly, Alan; Calamante, Fernando

    2016-03-01

    Advances in graph theory have provided a powerful tool to characterize brain networks. In particular, functional networks at group-level have great appeal to gain further insight into complex brain function, and to assess changes across disease conditions. These group networks, however, often have two main limitations. First, they are popularly estimated by directly averaging individual networks that are compromised by confounding variations. Secondly, functional networks have been estimated mainly through Pearson cross-correlation, without taking into account the influence of other regions. In this study, we propose a sparse group partial correlation method for robust estimation of functional networks based on a joint graphical models approach. To circumvent the issue of choosing the optimal regularization parameters, a stability selection method is employed to extract networks. The proposed method is, therefore, denoted as JGMSS. By applying JGMSS across simulated datasets, the resulting networks show consistently higher accuracy and sensitivity than those estimated using an alternative approach (the elastic-net regularization with stability selection, ENSS). The robustness of the JGMSS is evidenced by the independence of the estimated networks to choices of the initial set of regularization parameters. The performance of JGMSS in estimating group networks is further demonstrated with in vivo fMRI data (ASL and BOLD), which show that JGMSS can more robustly estimate brain hub regions at group-level and can better control intersubject variability than it is achieved using ENSS.

  17. Fluorescent macrocyclic probes with pendant functional groups as markers of acidic organelles within live cells.

    PubMed

    Wadhavane, Prashant D; Izquierdo, M Ángeles; Lutters, Dennis; Burguete, M Isabel; Marín, María J; Russell, David A; Galindo, Francisco; Luis, Santiago V

    2014-02-07

    A new family of acidity sensitive fluorescent macrocycles has been synthesized and fully characterized. Their photophysical properties including emission quantum yield and fluorescence lifetime have been determined. The acid-base properties of the new molecules can be tuned by the incorporation of pendant functional groups. The nature of such functional groups (carboxylic acid or ester) influences dramatically the pKa of the probes, two compounds of which exhibit low values. Preliminary intracellular studies using confocal microscopy together with emission spectra of the probes from the cellular environment have shown that the synthesized fluorescent macrocycles mark the acidic organelles of RAW 264.7 macrophage cells.

  18. Group I Metabotropic Glutamate Receptor Interacting Proteins: Fine-Tuning Receptor Functions in Health and Disease

    PubMed Central

    Kalinowska, Magdalena; Francesconi, Anna

    2016-01-01

    Group I metabotropic glutamate receptors mediate slow excitatory neurotransmission in the central nervous system and are critical to activity-dependent synaptic plasticity, a cellular substrate of learning and memory. Dysregulated receptor signaling is implicated in neuropsychiatric conditions ranging from neurodevelopmental to neurodegenerative disorders. Importantly, group I metabotropic glutamate receptor signaling functions can be modulated by interacting proteins that mediate receptor trafficking, expression and coupling efficiency to signaling effectors. These interactions afford cell- or pathway-specific modulation to fine-tune receptor function, thus representing a potential target for pharmacological interventions in pathological conditions. PMID:27296642

  19. Inhibition of human alcohol and aldehyde dehydrogenases by cimetidine and assessment of its effects on ethanol metabolism.

    PubMed

    Lai, Ching-Long; Li, Yeung-Pin; Liu, Chiu-Ming; Hsieh, Hsiu-Shan; Yin, Shih-Jiun

    2013-02-25

    Previous studies have reported that cimetidine, an H2-receptor antagonist used to treat gastric and duodenal ulcers, can inhibit alcohol dehydrogenases (ADHs) and ethanol metabolism. Human alcohol dehydrogenases and aldehyde dehydrogenases (ALDHs), the principal enzymes responsible for metabolism of ethanol, are complex enzyme families that exhibit functional polymorphisms among ethnic groups and distinct tissue distributions. We investigated the inhibition by cimetidine of alcohol oxidation by recombinant human ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, ADH1C2, ADH2, and ADH4, and aldehyde oxidation by ALDH1A1 and ALDH2 at pH 7.5 and a cytosolic NAD(+) concentration. Cimetidine acted as competitive or noncompetitive inhibitors for the ADH and ALDH isozymes/allozymes with near mM inhibition constants. The metabolic interactions between cimetidine and ethanol/acetaldehyde were assessed by computer simulation using the inhibition equations and the determined kinetic constants. At therapeutic drug levels (0.015 mM) and physiologically relevant concentrations of ethanol (10 mM) and acetaldehyde (10 μM) in target tissues, cimetidine could weakly inhibit (<5%) the activities of ADH1B2 and ADH1B3 in liver, ADH2 in liver and small intestine, ADH4 in stomach, and ALDH1A1 in the three tissues, but not significantly affect ADH1A, ADH1B1, ADH1C1/2, or ALDH2. At higher drug levels, which may accumulate in cells (0.2 mM), the activities of the weakly-inhibited enzymes may be decreased more significantly. The quantitative effects of cimetidine on metabolism of ethanol and other physiological substrates of ADHs need further investigation.

  20. [Responses of ground arthropod functional groups to the enclosure of grazing grassland in desert steppe].

    PubMed

    Liu, Ren-tao; Li, Xue-bin; Xin, Ming; Ma, Lin; Liu, Kai

    2011-08-01

    With the support of the National Resources Monitoring Station in Yanchi County of Ningxia, an investigation was conducted on the ground arthropods, vegetations, and soil properties in the enclosed and un-enclosed grazing grassland in desert steppe. In the meantime, the functional groups of ground arthropods were classified according to their feeding habits. The ground arthropods in the desert steppe could be classified into four functional groups, i.e., predatory, phytophagous, saprophagous, and omnivorous, among which, predatory and phytophagous groups were dominant in quantity, and phytophagous and saprophagous groups were predominant in biomass, implying that the ground arthropod in desert steppe was mainly characterized by phytophagous arthropods. Enclosure increased the individual and group number of predatory, phytophagous, and omnivorous arthropods as well as the biomass of predatory and omnivorous arthropods, and enhanced the biodiversity of predatory and phytophagous arthropods, which was closely correlated with the vegetation recovery and soil environment improvement, and demonstrated that the enclosure of grazing grassland increased the diversity and complexity of ground arthropod functional groups in desert steppe. Nevertheless, the individual number and biomass of saprophagous arthropods decreased after the enclosure, reflecting the dependence of these arthropods on grazing grassland.

  1. Chemoselective Reduction and Alkylation of Carbonyl Functions Using Phosphonium Salts as an in Situ Protecting Groups.

    PubMed

    Ohta, Reiya; Fujioka, Hiromichi

    2017-01-01

    Recent progress in the chemoselective reduction and alkylation of carbonyl functions using our in situ protection method is described. Methods that enable reversal or control of the reactivity of a carbonyl functional group are potentially useful. They open up new areas of synthetic organic chemistry and change the concept of retrosynthesis because they remove the need for complicated protection/deprotection sequences. In this account, we discuss the strategy and applications of our in situ protection method using phosphonium salts.

  2. A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

    PubMed Central

    Yang, Li; Emanuelsson, Rikard; Bergquist, Jonas; Strømme, Maria; Sjödin, Martin

    2016-01-01

    A new versatile polythiophene building block, 3-(3,4-ethylenedioxythiophene)prop-1-yne (pyEDOT) (3), is prepared from glycidol in four steps in 28% overall yield. pyEDOT features an ethynyl group on its ethylenedioxy bridge, allowing further functionalization by alkyne chemistry. Its usefulness is demonstrated by a series of functionalized polythiophene derivatives that were obtained by pre- and post-electropolymerization transformations, provided by the synthetic ease of the Sonogashira coupling and click chemistry. PMID:28144339

  3. Multiconfiguration pair-density functional theory: barrier heights and main group and transition metal energetics.

    PubMed

    Carlson, Rebecca K; Li Manni, Giovanni; Sonnenberger, Andrew L; Truhlar, Donald G; Gagliardi, Laura

    2015-01-13

    Kohn-Sham density functional theory, resting on the representation of the electronic density and kinetic energy by a single Slater determinant, has revolutionized chemistry, but for open-shell systems, the Kohn-Sham Slater determinant has the wrong symmetry properties as compared to an accurate wave function. We have recently proposed a theory, called multiconfiguration pair-density functional theory (MC-PDFT), in which the electronic kinetic energy and classical Coulomb energy are calculated from a multiconfiguration wave function with the correct symmetry properties, and the rest of the energy is calculated from a density functional, called the on-top density functional, that depends on the density and the on-top pair density calculated from this wave function. We also proposed a simple way to approximate the on-top density functional by translation of Kohn-Sham exchange-correlation functionals. The method is much less expensive than other post-SCF methods for calculating the dynamical correlation energy starting with a multiconfiguration self-consistent-field wave function as the reference wave function, and initial tests of the theory were quite encouraging. Here, we provide a broader test of the theory by applying it to bond energies of main-group molecules and transition metal complexes, barrier heights and reaction energies for diverse chemical reactions, proton affinities, and the water dimerization energy. Averaged over 56 data points, the mean unsigned error is 3.2 kcal/mol for MC-PDFT, as compared to 6.9 kcal/mol for Kohn-Sham theory with a comparable density functional. MC-PDFT is more accurate on average than complete active space second-order perturbation theory (CASPT2) for main-group small-molecule bond energies, alkyl bond dissociation energies, transition-metal-ligand bond energies, proton affinities, and the water dimerization energy.

  4. Retention of heavy metals by carboxyl functional groups of biochars in small arms range soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term effectiveness of biochar for heavy metal stabilization depends upon biochar’s sorptive property and recalcitrance in soil. To understand the role of carboxyl functional groups on heavy metal stabilization, cottonseed hull biochar and flax shive steam activated biochar having low O/C ratio...

  5. Social Resources and Change in Functional Health: Comparing Three Age Groups

    ERIC Educational Resources Information Center

    Randall, G. Kevin; Martin, Peter; Bishop, Alex J.; Johnson, Mary Ann; Poon, Leonard W.

    2012-01-01

    This study examined the mediating and moderating role of social resources on the association between age and change in functional health for three age groups of older adults. Data were provided by those in their 60s, 80s, and 100s who participated in the first two phases of the Georgia Centenarian study. Analyses confirmed the study's hypothesis…

  6. Neuropsychological Functioning in Specific Learning Disorders--Reading, Writing and Mixed Groups

    ERIC Educational Resources Information Center

    Kohli, Adarsh; Kaur, Manreet; Mohanty, Manju; Malhotra, Savita

    2006-01-01

    Aim: The study compared the pattern of deficits, intelligence and neuropsychological functioning in subcategories of learning disorders. Methods: Forty-six children (16 with reading disorders, 11 with writing disorders and 19 with both reading and writing disorders--mixed group) in the age range of 7-14 years were assessed using the NIMHANS Index…

  7. Group Social Skills Instruction for Adolescents with High-Functioning Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    White, Susan W.; Koenig, Kathleen; Scahill, Lawrence

    2010-01-01

    Given the increased recognition of autism spectrum disorders (ASD) and the chronic and pervasive nature of associated deficits, there is a pressing need for effective treatments. The feasibility and preliminary efficacy of a structured, group social skills training program for high-functioning youth with ASD was examined in this study. Fifteen…

  8. Beta-WAIS Comparisons with Low Functioning Minority Group Offenders: A Cautionary Note.

    ERIC Educational Resources Information Center

    Hiltonsmith, Robert W.; And Others

    1982-01-01

    Investigated the utility of the Revised Beta as a screening device for low-functioning minority-group criminal offenders. Mean scores for this sample were correlated only mildly. This finding contradicts prior research and creates the need for caution in using the Beta as a screening device with this population. (Author)

  9. Group-Specific Effects of Matching Subtest Contamination on the Identification of Differential Item Functioning

    ERIC Educational Resources Information Center

    Keiffer, Elizabeth Ann

    2011-01-01

    A differential item functioning (DIF) simulation study was conducted to explore the type and level of impact that contamination had on type I error and power rates in DIF analyses when the suspect item favored the same or opposite group as the DIF items in the matching subtest. Type I error and power rates were displayed separately for the…

  10. Detection of Differential Item Functioning for More than Two Groups: A Monte Carlo Comparison of Methods

    ERIC Educational Resources Information Center

    Finch, W. Holmes

    2016-01-01

    Differential item functioning (DIF) assessment is a crucial component in test construction, serving as the primary way in which instrument developers ensure that measures perform in the same way for multiple groups within the population. When such is not the case, scores may not accurately reflect the trait of interest for all individuals in the…

  11. Detecting Native Language Group Differences at the Subskills Level of Reading: A Differential Skill Functioning Approach

    ERIC Educational Resources Information Center

    Li, Hongli; Suen, Hoi K.

    2013-01-01

    Differential skill functioning (DSF) exists when examinees from different groups have different probabilities of successful performance in a certain subskill underlying the measured construct, given that they have the same ability on the overall construct. Using a DSF approach, this study examined the differences between two native language…

  12. A FUNCTIONAL GROUP CHARACTERIZATION OF ORGANIC PM 2.5 EXPOSURE: RESULTS FROM THE RIOPA STUDY

    EPA Science Inventory

    The functional group (FG) composition of urban residential outdoor, indoor, and personal fine particle (PM2.5) samples is presented and used to provide insights relevant to organic PM2.5 exposure. PM2.5 samples (48 h) were collected during the Rel...

  13. Unitary representations of three dimensional Lie groups revisited: A short tutorial via harmonic functions

    NASA Astrophysics Data System (ADS)

    Campoamor-Stursberg, R.; Rausch de Traubenberg, M.

    2017-04-01

    The representation theory of three dimensional real and complex Lie groups is reviewed from the perspective of harmonic functions defined over certain appropriate manifolds. An explicit construction of all unitary representations is given. The realisations obtained are shown to be related with each other by either natural operations as real forms or Inönü-Wigner contractions.

  14. Chemkarta: A Card Game for Teaching Functional Groups in Undergraduate Organic Chemistry

    ERIC Educational Resources Information Center

    Knudtson, Christopher A.

    2015-01-01

    Students in undergraduate organic chemistry courses are frequently overwhelmed by the volume and complexity of information they are expected to learn. To aid in students' learning of organic functional groups, a novel card game "ChemKarta" is reported that can serve as a useful alternative to flashcards. This pedagogy is a simple…

  15. IMPORTANCE OF ACTIVATED CARBON'S OXYGEN SURFACE FUNCTIONAL GROUPS ON ELEMENTAL MERCURY ADSORPTION

    EPA Science Inventory

    The effect of varying physical and chemical properties of activated carbons on adsorption of elemental mercury [Hg(0)] was studied by treating two activated carbons to modify their surface functional groups and pore structures. Heat treatment (1200 K) in nitrogen (N2), air oxidat...

  16. 14 CFR 10 - Functional Classification-Operating Expenses of Group I Air Carriers

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Functional Classification-Operating Expenses of Group I Air Carriers Section 10 Section Section 10 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR...

  17. Review of Social Skills Training Groups for Youth with Asperger Syndrome and High Functioning Autism

    ERIC Educational Resources Information Center

    Cappadocia, M. Catherine; Weiss, Jonathan A.

    2011-01-01

    Although social skills deficits represent core symptoms of Asperger Syndrome and High Functioning Autism, there is limited research investigating the empirical validity of social skills interventions currently being used with these populations. This literature review compares three types of social skills training groups: traditional, cognitive…

  18. Urinary Cortisol Circadian Rhythm in a Group of High-Functioning Children with Autism.

    ERIC Educational Resources Information Center

    Richdale, Amanda L.; Prior, Margot R.

    1992-01-01

    This study found no evidence for abnormal temporal placement of the basal urinary cortisol circadian rhythm in a group of 18 high-functioning children (ages 4-14) with autism. There was a tendency toward cortisol hypersecretion during the day, predominantly in autistic children who were integrated into the normal school system. (Author/JDD)

  19. An Epistemological Inquiry into Organic Chemistry Education: Exploration of Undergraduate Students' Conceptual Understanding of Functional Groups

    ERIC Educational Resources Information Center

    Akkuzu, Nalan; Uyulgan, Melis Arzu

    2016-01-01

    This study sought to determine the levels of conceptual understanding of undergraduate students regarding organic compounds within different functional groups. A total of 60 students who were enrolled in the Department of Secondary Science and Mathematics Education of a Faculty of Education at a state university in Turkey and who had followed an…

  20. Class-Wide Function-Related Intervention Teams: Effects of Group Contingency Programs in Urban Classrooms

    ERIC Educational Resources Information Center

    Kamps, Debra; Wills, Howard P.; Heitzman-Powell, Linda; Laylin, Jeff; Szoke, Carolyn; Petrillo, Tai; Culey, Amy

    2011-01-01

    The purpose of the study was to determine the effectiveness of the Class-Wide Function-related Intervention Teams (CW-FIT) program, a group contingency intervention for whole classes, and for students with disruptive behaviors who are at risk for emotional/behavioral disorders (EBD). The CW-FIT program includes four elements designed from…

  1. Refinements to the structure of graphite oxide: absolute quantification of functional groups via selective labelling.

    PubMed

    Eng, Alex Yong Sheng; Chua, Chun Kiang; Pumera, Martin

    2015-12-21

    Chemical modification and functionalization of inherent functional groups within graphite oxide (GO) are essential aspects of graphene-based nano-materials used in wide-ranging applications. Despite extensive research, there remains some discrepancy in its structure, with current knowledge limited primarily to spectroscopic data from XPS, NMR and vibrational spectroscopies. We report herein an innovative electrochemistry-based approach. Four electroactive labels are chosen to selectively functionalize groups in GO, and quantification of each group is achieved by voltammetric analysis. This allows for the first time quantification of absolute amounts of each group, with a further advantage of distinguishing various carbonyl species: namely ortho- and para-quinones from aliphatic ketones. Intrinsic variations in the compositions of permanganate versus chlorate-oxidized GOs were thus observed. Principal differences include permanganate-GO exhibiting substantial quinonyl content, in comparison to chlorate-GO with the vast majority of its carbonyls as isolated ketones. The results confirm that carboxylic groups are rare in actuality, and are in fact entirely absent from chlorate-GO. These observations refine and advance our understanding of GO structure by addressing certain disparities in past models resulting from employment of different oxidation routes, with the vital implication that GO production methods cannot be used interchangeably in the manufacture of graphene-based devices.

  2. Increased acetyl group availability enhances contractile function of canine skeletal muscle during ischemia.

    PubMed Central

    Timmons, J A; Poucher, S M; Constantin-Teodosiu, D; Worrall, V; Macdonald, I A; Greenhaff, P L

    1996-01-01

    Skeletal muscle contractile function is impaired during acute ischemia such as that experienced by peripheral vascular disease patients. We therefore, examined the effects of dichloroacetate, which can alter resting metabolism, on canine gracilis muscle contractile function during constant flow ischemia. Pretreatment with dichloroacetate increased resting pyruvate dehydrogenase complex activity and resting acetylcarnitine concentration by approximately 4- and approximately 10-fold, respectively. After 20-min contraction the control group had demonstrated an approximately 40% reduction in isomeric tension whereas the dichloroacetate group had fatigued by approximately 25% (P < 0.05). Dichloroacetate resulted in less lactate accumulation (10.3 +/- 3.0 vs 58.9 +/- 10.5 mmol.kg-1 dry muscle [dm], P < 0.05) and phosphocreatine hydrolysis (15.6 +/- 6.3 vs 33.8 +/- 9.0 mmol.kg-1 dm, P < 0.05) during contraction. Acetylcarnitine concentration fell during contraction by 5.4 +/- 1.8 mmol.kg-1 dm in the dichloroacetate group but increased by 10.0 +/- 1.9 mmol.kg-1 dm in the control group. In conclusion, dichloroacetate enhanced contractile function during ischemia, independently of blood flow, such that it appears oxidative ATP regeneration is limited by pyruvate dehydrogenase complex activity and acetyl group availability. PMID:8609248

  3. Functional group analysis of natural organic colloids and clay association kinetics using C(1s) spectromicroscopy

    NASA Astrophysics Data System (ADS)

    Schäfer, T.; Hertkorn, N.; Artinger, R.; Claret, F.; Bauer, A.

    2003-03-01

    The quantification of natural humic colloid functional group content and chemical association of humic substances with clay minerals exerts a crucial role in the colloid-borne mobility of actinides due to the functional group dependent strong interaction with multivalent metal ions. Functional group quantification in isolated fulvic acids of the Gorleben groundwater (Lower Saxony, NW Germany) by comparison of high resolution C(1s) NEXAFS spectra deconvolution with ^{13}C-NMR measurements showed good correlation (r^2> 0.9) and gives a potential quantification tool in complex natural groundwater Systems. Time resolved soft X-ray spectromicroscopy on dissolved organic carbon stabilized SWy-2 smectite colloids revealed an enrichment of carboxyl groups on broken edges (silanol/aluminol groups) at short contact times (1h). With longer contact times (7d, 6 months) the clay associated organic carbon increases and significantly higher aromatic content associated with basal surfaces were detected. The enhanced sorption of aromatic compounds can be related to an increase in mineral surface hydrophobicity and/or preferential sorption on charged siloxane surfaces.

  4. Organic functional group transformations in water at elevated temperature and pressure: Reversibility, reactivity, and mechanisms

    NASA Astrophysics Data System (ADS)

    Shipp, Jessie; Gould, Ian R.; Herckes, Pierre; Shock, Everett L.; Williams, Lynda B.; Hartnett, Hilairy E.

    2013-03-01

    Many transformation reactions involving hydrocarbons occur in the presence of H2O in hydrothermal systems and deep sedimentary systems. We investigate these reactions using laboratory-based organic chemistry experiments at high temperature and pressure (300 °C and 100 MPa). Organic functional group transformation reactions using model organic compounds based on cyclohexane with one or two methyl groups provided regio- and stereochemical markers that yield information about reversibility and reaction mechanisms. We found rapidly reversible interconversion between alkanes, alkenes, dienes, alcohols, ketones, and enones. The alkane-to-ketone reactions were not only completely reversible, but also exhibited such extensive reversibility that any of the functional groups along the reaction path (alcohol, ketone, and even the diene) could be used as the reactant and form all the other groups as products. There was also a propensity for these ring-based structures to dehydrogenate; presumably from the alkene, through a diene, to an aromatic ring. The product suites provide strong evidence that water behaved as a reactant and the various functional groups showed differing degrees of reactivity. Mechanistically-revealing products indicated reaction mechanisms that involve carbon-centered cation intermediates. This work therefore demonstrates that a wide range of organic compound types can be generated by abiotic reactions at hydrothermal conditions.

  5. Insights into the Competing Mechanisms and Origin of Enantioselectivity for N-Heterocyclic Carbene-Catalyzed Reaction of Aldehyde with Enamide

    NASA Astrophysics Data System (ADS)

    Qiao, Yan; Chen, Xinhuan; Wei, Donghui; Chang, Junbiao

    2016-12-01

    Hydroacylation reactions and aza-benzoin reactions have attracted considerable attention from experimental chemists. Recently, Wang et al. reported an interesting reaction of N-heterocyclic carbene (NHC)-catalyzed addition of aldehyde to enamide, in which both hydroacylation and aza-benzoin reactions may be involved. Thus, understanding the competing relationship between them is of great interest. Now, density functional theory (DFT) investigation was performed to elucidate this issue. Our results reveal that enamide can tautomerize to its imine isomer with the assistance of HCO3‑. The addition of NHC to aldehydes formed Breslow intermediate, which can go through cross-coupling with enamide via hydroacylation reaction or its imine isomer via aza-benzoin reaction. The aza-benzoin reaction requires relatively lower free energy barrier than the hydroacylation reaction. The more polar characteristic of C=N group in the imine isomers, and the more advantageous stereoelectronic effect in the carbon-carbon bond forming transition states in aza-benzoin pathway were identified to determine that the imine isomer can react with the Breslow intermediate more easily. Furthermore, the origin of enantioselectivities for the reaction was explored and reasonably explained by structural analyses on key transition states. The work should provide valuable insights for rational design of switchable NHC-catalyzed hydroacylation and aza-benzoin reactions with high stereoselectivity.

  6. Insights into the Competing Mechanisms and Origin of Enantioselectivity for N-Heterocyclic Carbene-Catalyzed Reaction of Aldehyde with Enamide

    PubMed Central

    Qiao, Yan; Chen, Xinhuan; Wei, Donghui; Chang, Junbiao

    2016-01-01

    Hydroacylation reactions and aza-benzoin reactions have attracted considerable attention from experimental chemists. Recently, Wang et al. reported an interesting reaction of N-heterocyclic carbene (NHC)-catalyzed addition of aldehyde to enamide, in which both hydroacylation and aza-benzoin reactions may be involved. Thus, understanding the competing relationship between them is of great interest. Now, density functional theory (DFT) investigation was performed to elucidate this issue. Our results reveal that enamide can tautomerize to its imine isomer with the assistance of HCO3−. The addition of NHC to aldehydes formed Breslow intermediate, which can go through cross-coupling with enamide via hydroacylation reaction or its imine isomer via aza-benzoin reaction. The aza-benzoin reaction requires relatively lower free energy barrier than the hydroacylation reaction. The more polar characteristic of C=N group in the imine isomers, and the more advantageous stereoelectronic effect in the carbon-carbon bond forming transition states in aza-benzoin pathway were identified to determine that the imine isomer can react with the Breslow intermediate more easily. Furthermore, the origin of enantioselectivities for the reaction was explored and reasonably explained by structural analyses on key transition states. The work should provide valuable insights for rational design of switchable NHC-catalyzed hydroacylation and aza-benzoin reactions with high stereoselectivity. PMID:27905524

  7. Inhibition of the Aldehyde Dehydrogenase 1/2 Family by Psoralen and Coumarin Derivatives.

    PubMed

    Buchman, Cameron D; Hurley, Thomas D

    2017-03-23

    Aldehyde dehydrogenase 2 (ALDH2), one of 19 ALDH superfamily members, catalyzes the NAD(+)-dependent oxidation of aldehydes to their respective carboxylic acids. In this study, we further characterized the inhibition of four psoralen and coumarin derivatives toward ALDH2 and compared them to the ALDH2 inhibitor daidzin for selectivity against five ALDH1/2 isoenzymes. Compound 2 (Ki = 19 nM) binds within the aldehyde-binding site of the free enzyme species of ALDH2. Thirty-three structural analogs were examined to develop a stronger SAR profile. Seven compounds maintained or improved upon the selectivity toward one of the five ALDH1/2 isoenzymes, including compound 36, a selective inhibitor for ALDH2 (Ki = 2.4 μM), and compound 32, which was 10-fold selective for ALDH1A1 (Ki = 1.2 μM) versus ALDH1A2. Further medicinal chemistry on the compounds' basic scaffold could enhance the potency and selectivity for ALDH1A1 or ALDH2 and generate chemical probes to examine the unique and overlapping functions of the ALDH1/2 isoenzymes.

  8. Drude polarizable force field for aliphatic ketones and aldehydes, and their associated acyclic carbohydrates

    NASA Astrophysics Data System (ADS)

    Small, Meagan C.; Aytenfisu, Asaminew H.; Lin, Fang-Yu; He, Xibing; MacKerell, Alexander D.

    2017-02-01

    The majority of computer simulations exploring biomolecular function employ Class I additive force fields (FF), which do not treat polarization explicitly. Accordingly, much effort has been made into developing models that go beyond the additive approximation. Development and optimization of the Drude polarizable FF has yielded parameters for selected lipids, proteins, DNA and a limited number of carbohydrates. The work presented here details parametrization of aliphatic aldehydes and ketones (viz. acetaldehyde, propionaldehyde, butaryaldehyde, isobutaryaldehyde, acetone, and butanone) as well as their associated acyclic sugars (uc(d)-allose and uc(d)-psicose). LJ parameters are optimized targeting experimental heats of vaporization and molecular volumes, while the electrostatic parameters are optimized targeting QM water interactions, dipole moments, and molecular polarizabilities. Bonded parameters are targeted to both QM and crystal survey values, with the models for ketones and aldehydes shown to be in good agreement with QM and experimental target data. The reported heats of vaporization and molecular volumes represent a compromise between the studied model compounds. Simulations of the model compounds show an increase in the magnitude and the fluctuations of the dipole moments in moving from gas phase to condensed phases, which is a phenomenon that the additive FF is intrinsically unable to reproduce. The result is a polarizable model for aliphatic ketones and aldehydes including the acyclic sugars uc(d)-allose and uc(d)-psicose, thereby extending the available biomolecules in the Drude polarizable FF.

  9. Localization and attempted quantification of various functional groups on pulpwood fibres

    NASA Astrophysics Data System (ADS)

    Klash, A.; Ncube, E.; Meincken, M.

    2009-04-01

    The distribution of different free chemical functional groups on wood and pulp fibres has been determined by means of atomic force microscopy (AFM) with chemically modified tips. Because these functional groups show a higher affinity to similar groups on the substrate surface during scanning, AFM images determined with an additional digital pulsed-force mode (DPFM) controller allow the distribution of the chemical components to be imaged and to a degree also to be quantified. The investigated tip coatings showed a different sensitivity towards the major chemical components present in wood fibres, determined on spin-coated films and on wood fibres. A clear distinction between cellulose and lignin was possible in both cases. This technique could therefore be used to differentiate between cellulose and lignin present on pulp fibre surfaces and confirm the successful removal of lignin by pulping.

  10. A SPARSE REDUCED RANK FRAMEWORK FOR GROUP ANALYSIS OF FUNCTIONAL NEUROIMAGING DATA.

    PubMed

    Ahn, Mihye; Shen, Haipeng; Lin, Weili; Zhu, Hongtu

    2015-01-01

    In spatial-temporal neuroimaging studies, there is an evolving literature on the analysis of functional imaging data in order to learn the intrinsic functional connectivity patterns among different brain regions. However, there are only few efficient approaches for integrating functional connectivity pattern across subjects, while accounting for spatial-temporal functional variation across multiple groups of subjects. The objective of this paper is to develop a new sparse reduced rank (SRR) modeling framework for carrying out functional connectivity analysis across multiple groups of subjects in the frequency domain. Our new framework not only can extract both frequency and spatial factors across subjects, but also imposes sparse constraints on the frequency factors. It thus leads to the identification of important frequencies with high power spectra. In addition, we propose two novel adaptive criteria for automatic selection of sparsity level and model rank. Using simulated data, we demonstrate that SRR outperforms several existing methods. Finally, we apply SRR to detect group differences between controls and two subtypes of attention deficit hyperactivity disorder (ADHD) patients, through analyzing the ADHD-200 data.

  11. A meta-analysis of functional group responses to forest recovery outside of the tropics.

    PubMed

    Spake, Rebecca; Ezard, Thomas H G; Martin, Philip A; Newton, Adrian C; Doncaster, C Patrick

    2015-12-01

    Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old-growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta-analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old-growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional-group-specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old-growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old-growth values (between 140 years and never for recovery to old-growth values at 95% prediction limits). Non-saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old-growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives.

  12. Structural and functional evolution of the P2Y12-like receptor group

    PubMed Central

    Hermsdorf, Thomas; Engemaier, Eva; Engel, Kathrin; Liebscher, Ines; Thor, Doreen; Zierau, Klaas; Römpler, Holger; Schulz, Angela

    2007-01-01

    Metabotropic pyrimidine and purine nucleotide receptors (P2Y receptors) belong to the superfamily of G protein-coupled receptors (GPCR). They are distinguishable from adenosine receptors (P1) as they bind adenine and/or uracil nucleotide triphosphates or diphosphates depending on the subtype. Over the past decade, P2Y receptors have been cloned from a variety of tissues and species, and as many as eight functional subtypes have been characterized. Most recently, several members of the P2Y12-like receptor group, which includes the clopidogrel-sensitive ADP receptor P2Y12, have been deorphanized. The P2Y12-like receptor group comprises several structurally related GPCR which, however, display heterogeneous agonist specificity including nucleotides, their derivatives, and lipids. Besides the established function of P2Y12 in platelet activation, expression in macrophages, neuronal and glial cells as well as recent results from functional studies implicate that several members of this group may have specific functions in neurotransmission, inflammation, chemotaxis, and response to tissue injury. This review focuses specifically on the structure-function relation and shortly summarizes some aspects of the physiological relevance of P2Y12-like receptor members. PMID:18404440

  13. The Dragonfly Nearby Galaxies Survey. III. The Luminosity Function of the M101 Group

    NASA Astrophysics Data System (ADS)

    Danieli, Shany; van Dokkum, Pieter; Merritt, Allison; Abraham, Roberto; Zhang, Jielai; Karachentsev, I. D.; Makarova, L. N.

    2017-03-01

    We obtained follow-up HST observations of the seven low surface brightness galaxies discovered with the Dragonfly Telephoto Array in the field of the massive spiral galaxy M101. Out of the seven galaxies, only three were resolved into stars and are potentially associated with the M101 group at D = 7 Mpc. Based on HST ACS photometry in the broad F606W and F814W filters, we use a maximum likelihood algorithm to locate the Tip of the Red Giant Branch in galaxy color–magnitude diagrams. Distances are {6.38}-0.35+0.35,{6.87}-0.30+0.21 and {6.52}-0.27+0.25 {Mpc} and we confirm that they are members of the M101 group. Combining the three confirmed low-luminosity satellites with previous results for brighter group members, we find the M101 galaxy group to be a sparsely populated galaxy group consisting of seven group members, down to M V = ‑9.2 mag. We compare the M101 cumulative luminosity function to that of the Milky Way and M31. We find that they are remarkably similar; in fact, the cumulative luminosity function of the M101 group gets even flatter for fainter magnitudes, and we show that the M101 group might exhibit the two known small-scale flaws in the ΛCDM model, namely “the missing satellite” problem and the “too big to fail” problem. Kinematic measurements of M101's satellite galaxies are required to determine whether the “too big to fail” problem does in fact exist in the M101 group.

  14. Effect of Habitat Size, Quality, and Isolation on Functional Groups of Beetles in Hollow Oaks

    PubMed Central

    Pilskog, Hanne Eik; Birkemoe, Tone; Framstad, Erik; Sverdrup-Thygeson, Anne

    2016-01-01

    One of the largest threats to biodiversity is land use change and habitat loss. Hollow oaks (Quercus spp. L.) are well-defined patches that are hotspots for biodiversity and red-listed species, but they are often rare and fragmented in the landscape. We investigated the effect of patch size, habitat quality, and isolation on functional groups and red-listed saproxylic beetles in hollow oaks (n = 40) in Norway. The groups were defined by host tree association, trophic grouping, and red-listed status. Habitat quality, represented by tree form was most important in explaining species richness for most groups. Patch size, represented by circumference and amount of dead branches, was most important in explaining abundance. Isolation, that is single oaks compared with oaks in groups, had a negative effect on the abundance of beetles feeding both on wood and fungi (xylomycethopagous), as well as on species associated with broadleaved trees (oak semi-specialists), but did not affect species richness. This indicates that at this scale and in this landscape, isolated oaks are as species rich and valuable for conservation as other oaks, although some functional groups may be more vulnerable to isolation than others. The red-listed species only responded to patch size, indicating that oaks with large circumference and many dead branches are especially important for red-listed species and for conservation. PMID:26945089

  15. Effect of Habitat Size, Quality, and Isolation on Functional Groups of Beetles in Hollow Oaks.

    PubMed

    Pilskog, Hanne Eik; Birkemoe, Tone; Framstad, Erik; Sverdrup-Thygeson, Anne

    2016-01-01

    One of the largest threats to biodiversity is land use change and habitat loss. Hollow oaks (Quercus spp. L.) are well-defined patches that are hotspots for biodiversity and red-listed species, but they are often rare and fragmented in the landscape. We investigated the effect of patch size, habitat quality, and isolation on functional groups and red-listed saproxylic beetles in hollow oaks (n = 40) in Norway. The groups were defined by host tree association, trophic grouping, and red-listed status. Habitat quality, represented by tree form was most important in explaining species richness for most groups. Patch size, represented by circumference and amount of dead branches, was most important in explaining abundance. Isolation, that is single oaks compared with oaks in groups, had a negative effect on the abundance of beetles feeding both on wood and fungi (xylomycethopagous), as well as on species associated with broadleaved trees (oak semi-specialists), but did not affect species richness. This indicates that at this scale and in this landscape, isolated oaks are as species rich and valuable for conservation as other oaks, although some functional groups may be more vulnerable to isolation than others. The red-listed species only responded to patch size, indicating that oaks with large circumference and many dead branches are especially important for red-listed species and for conservation.

  16. Development of Acid Functional Groups and Lactones During the Thermal Degradation of Wood and Wood Components

    USGS Publications Warehouse

    Rutherford, David W.; Wershaw, Robert L.; Reeves, James B.

    2008-01-01

    Black carbon (pyrogenic materials including chars) in soils has been recognized as a substantial portion of soil organic matter, and has been shown to play a vital role in nutrient cycling; however, little is known concerning the properties of this material. Previous studies have largely been concerned with the creation of high-surface-area materials for use as sorbents. These materials have been manufactured at high temperature and have often been activated. Chars occurring in the environment can be formed over a wide range of temperature. Because it is extremely difficult to isolate black carbon once it has been incorporated in soils, chars produced in the laboratory under controlled conditions can be used to investigate the range of properties possible for natural chars. This report shows that charring conditions (temperature and time) have substantial impact on the acid functional group and lactone content of chars. Low temperatures (250?C) and long charring times (greater than 72 hours) produce chars with the highest acid functional group and lactone content. The charring of cellulose appears to be responsible for the creation of the acid functional group and lactones. The significance of this study is that low-temperature chars can have acid functional group contents comparable to humic materials (as high as 8.8 milliequivalents per gram). Acid functional group and lactone content decreases as charring temperature increases. The variation in formation conditions expected under natural fire conditions will result in a wide range of sorption properties for natural chars which are an important component of soil organic matter. By controlling the temperature and duration of charring, it is possible to tailor the sorption properties of chars, which may be used as soil amendments.

  17. Multi-regulator functional renormalization group for many-fermion systems

    NASA Astrophysics Data System (ADS)

    Tanizaki, Yuya; Hatsuda, Tetsuo

    We propose a method of multi-regulator functional renormalization group (MR-FRG) which is a novel formulation of functional renormalization group with multiple infrared (IR) regulators. It is applied to a two-component fermionic system with an attractive contact interaction to study crossover phenomena between the Bardeen-Cooper-Schrieffer (BCS) phase and the Bose-Einstein condensation (BEC) phase. To control both the fermionic one-particle excitations and the bosonic collective excitations, IR regulators are introduced, one for the fermionic two-point function and another for the four-fermion vertex. It is shown that the Nozières-Schmitt-Rink (NSR) theory, which is successful to capture qualitative features of the BCS-BEC crossover, can be derived from MR-FRG. Some aspects of MR-FRG to go beyond the NSR theory are also discussed.

  18. Quantification of protein group coherence and pathway assignment using functional association

    PubMed Central

    2011-01-01

    Background Genomics and proteomics experiments produce a large amount of data that are awaiting functional elucidation. An important step in analyzing such data is to identify functional units, which consist of proteins that play coherent roles to carry out the function. Importantly, functional coherence is not identical with functional similarity. For example, proteins in the same pathway may not share the same Gene Ontology (GO) terms, but they work in a coordinated fashion so that the aimed function can be performed. Thus, simply applying existing functional similarity measures might not be the best solution to identify functional units in omics data. Results We have designed two scores for quantifying the functional coherence by considering association of GO terms observed in two biological contexts, co-occurrences in protein annotations and co-mentions in literature in the PubMed database. The counted co-occurrences of GO terms were normalized in a similar fashion as the statistical amino acid contact potential is computed in the protein structure prediction field. We demonstrate that the developed scores can identify functionally coherent protein sets, i.e. proteins in the same pathways, co-localized proteins, and protein complexes, with statistically significant score values showing a better accuracy than existing functional similarity scores. The scores are also capable of detecting protein pairs that interact with each other. It is further shown that the functional coherence scores can accurately assign proteins to their respective pathways. Conclusion We have developed two scores which quantify the functional coherence of sets of proteins. The scores reflect the actual associations of GO terms observed either in protein annotations or in literature. It has been shown that they have the ability to accurately distinguish biologically relevant groups of proteins from random ones as well as a good discriminative power for detecting interacting pairs of

  19. Wetting properties of model interphases coated with defined organic functional groups

    NASA Astrophysics Data System (ADS)

    Woche, Susanne K.; Goebel, Marc-O.; Guggenberger, Georg; Tunega, Daniel; Bachmann, Joerg

    2013-04-01

    Surface properties of soil particles are of particular interest regarding transport of water and sorption of solutes, especially hazardous xenobiotic species. Wetting properties (e.g. determined by contact angle, CA), governed by the functional groups exposed, are crucial to understand sorption processes in water repellent soils as well as for the geometry of water films sustaining microbial processes on the pore scale. Natural soil particle surfaces are characterized by a wide variety of mineralogical and chemical compounds. Their composition is almost impossible to identify in full. Hence, in order to get a better understanding about surface properties, an option is the usage of defined model surfaces, whereas the created surface should be comparable to natural soil interphases. We exposed smooth glass surfaces to different silane compounds, resulting in a coating covalently bound to the surface and exhibiting defined organic functional groups towards the pore space. The wetting properties as evaluated by CA and the surface free energy (SFE), calculated according to the Acid-Base Theory, were found to be a function of the specific functional group. Specifically, the treated surfaces showed a large variation of CA and SFE as function of chain length and polarity of the organic functional group. The study of wetting properties was accompanied by XPS analysis for selective detection of chemical compounds of the interphase. As the reaction mechanism of the coating process is known, the resulting interphase structure can be modeled based on energetic considerations. A next step is to use same coatings for the defined modification of the pore surfaces of porous media to study transport and sorption processes in complex three phase systems.

  20. Zooplankton functional groups on the continental shelf of the yellow sea

    NASA Astrophysics Data System (ADS)

    Sun, Song; Huo, Yuanzi; Yang, Bo

    2010-06-01

    Zooplankton plays a vital role in marine ecosystems. Variations in the zooplankton species composition, biomass, and secondary production will change the structure and function of the ecosystem. How to describe this process and make it easier to be modeled in the Yellow Sea ecosystem is the main purpose of this paper. The zooplankton functional groups approach, which is considered a good method of linking the structure of food webs and the energy flow in the ecosystems, is used to describe the main contributors of secondary produciton of the Yellow Sea ecosystem. The zooplankton can be classified into six functional groups: giant crustaceans, large copepods, small copepods, chaetognaths, medusae, and salps. The giant crustaceans, large copepods, and small copepods groups, which are the main food resources for fish, are defined depending on the size spectrum. Medusae and chaetognaths are the two gelatinous carnivorous groups, which compete with fish for food. The salps group, acting as passive filter-feeders, competes with other species feeding on phytoplankton, but their energy could not be efficiently transferred to higher trophic levels. From the viewpoint of biomass, which is the basis of the food web, and feeding activities, the contributions of each functional group to the ecosystem were evaluated; the seasonal variations, geographical distribution patterns, and species composition of each functional group were analyzed. The average zooplankton biomass was 2.1 g dry wt m -2 in spring, to which the giant crustaceans, large copepods, and small copepods contributed 19, 44, and 26%, respectively. High biomasses of the large copepods and small copepods were distributed at the coastal waters, while the giant crustaceans were mainly located at offshore area. In summer, the mean biomass was 3.1 g dry wt m -2, which was mostly contributed by the giant crustaceans (73%), and high biomasses of the giant crustaceans, large copepods, and small copepods were all distributed

  1. The effect of affective bibliotherapy on clients' functioning in group therapy.

    PubMed

    Shechtman, Zipora; Nir-Shfrir, Rivka

    2008-01-01

    Abstract The effect of affective group bibliotherapy (GB) was compared to affective group therapy (GT) on patients' functioning in therapy and their session impression. Three small groups totaling twenty-five in-patients in a hospital in Israel participated in the study. Clients concurrently participated in both group types, undergoing three sessions in each condition. In-therapy behaviors were assessed through the Client Behavior System (CBS; Hill & O'Brien, 1999). Results indicated that in the GB condition compared to the GT condition, clients showed less resistance, used simple responses less frequently, and expressed greater affective exploration. The Session Evaluation Questionnaire (SEQ; Stiles et al., 1994) was used to measure clients' impressions of the sessions. Results indicated that patients evaluated the two treatment conditions equally. Overall, the results support earlier findings, suggesting that affective bibliotherapy can be an effective method of treatment.

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

    SciTech Connect

    Fifield, Leonard S.; Grate, Jay W.

    2010-06-01

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

  3. Kelvin-probe force microscopy of the pH-dependent charge of functional groups

    NASA Astrophysics Data System (ADS)

    Stone, Alexander D. D.; Mesquida, Patrick

    2016-06-01

    Kelvin-probe Force Microscopy (KFM) is an established method to map surface potentials or surface charges at high, spatial resolution. However, KFM does not work in water, which restricts its applicability considerably, especially when considering common, functional chemical groups in biophysics such as amine or carboxy groups, whose charge depends on pH. Here, we demonstrate that the KFM signal of such groups taken in air after exposure to water correlates qualitatively with their expected charge in water for a wide range of pH values. The correlation was tested with microcontact-printed thiols exposing amine and carboxy groups. Furthermore, it was shown that collagen fibrils, as an example of a biological material, exhibit a particular, pH-sensitive surface charge pattern, which could be caused by the particular arrangement of ionizable residues on the collagen fibril surface.

  4. Matrix intensification alters avian functional group composition in adjacent rainforest fragments.

    PubMed

    Deikumah, Justus P; McAlpine, Clive A; Maron, Martine

    2013-01-01

    Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining.

  5. Photochemical and antimicrobial properties of silver nanoparticle-encapsulated chitosan functionalized with photoactive groups.

    PubMed

    Mathew, Thomas V; Kuriakose, Sunny

    2013-10-01

    Chitosan was functionalized with 4-((E)-2-(3-hydroxynaphthalen-2-yl)diazen-1-yl)benzoic acid by the coupling of the hydroxyl functional groups of chitosan with carboxylic acid group of the dye by DCC coupling method. The silver nanoparticles were prepared by sol-gel method of nanoparticle synthesis. Silver nanoparticle-encapsulated functionalized chitosan was prepared by the phase transfer method. The products were characterized by FTIR, UV-Vis, fluorescence and NMR spectroscopic methods and by SEM and TEM analysis. The photochemical properties of silver nanoparticle-encapsulated chitosan functionalized with 4-((E)-2-(3-hydroxynaphthalen-2-yl)diazen-1-yl)benzoic acid was studied in detail. The light-fastening properties of the chromophoric system was enhanced when attached to chitosan, and it can be further improved by the encapsulation of silver nanoparticles. The antibacterial analysis of silver nanoparticle-encapsulated functionalized chitosan was carried out against Staphylococcus aureus and Escherichia coli and against fungal species such as Aspergillus flavus and Aspergillus terreus. This study showed that silver nanoparticles-encapsulated functionalized chitosan can be used for antibacterial and antifungal applications.

  6. Refinements to the structure of graphite oxide: absolute quantification of functional groups via selective labelling

    NASA Astrophysics Data System (ADS)

    Eng, Alex Yong Sheng; Chua, Chun Kiang; Pumera, Martin

    2015-11-01

    Chemical modification and functionalization of inherent functional groups within graphite oxide (GO) are essential aspects of graphene-based nano-materials used in wide-ranging applications. Despite extensive research, there remains some discrepancy in its structure, with current knowledge limited primarily to spectroscopic data from XPS, NMR and vibrational spectroscopies. We report herein an innovative electrochemistry-based approach. Four electroactive labels are chosen to selectively functionalize groups in GO, and quantification of each group is achieved by voltammetric analysis. This allows for the first time quantification of absolute amounts of each group, with a further advantage of distinguishing various carbonyl species: namely ortho- and para-quinones from aliphatic ketones. Intrinsic variations in the compositions of permanganate versus chlorate-oxidized GOs were thus observed. Principal differences include permanganate-GO exhibiting substantial quinonyl content, in comparison to chlorate-GO with the vast majority of its carbonyls as isolated ketones. The results confirm that carboxylic groups are rare in actuality, and are in fact entirely absent from chlorate-GO. These observations refine and advance our understanding of GO structure by addressing certain disparities in past models resulting from employment of different oxidation routes, with the vital implication that GO production methods cannot be used interchangeably in the manufacture of graphene-based devices.Chemical modification and functionalization of inherent functional groups within graphite oxide (GO) are essential aspects of graphene-based nano-materials used in wide-ranging applications. Despite extensive research, there remains some discrepancy in its structure, with current knowledge limited primarily to spectroscopic data from XPS, NMR and vibrational spectroscopies. We report herein an innovative electrochemistry-based approach. Four electroactive labels are chosen to selectively

  7. Quantity of Hydrophobic Functional CH-Groups - Decisive for Soil Water Repellency Caused by Digestate Amendment

    NASA Astrophysics Data System (ADS)

    Voelkner, Amrei; Holthusen, Dörthe; Ellerbrock, Ruth H.; Horn, Rainer

    2015-04-01

    Anaerobic digestates are used as organic fertilizers; however, they are suspected to interfere negatively with soils. To investigate the relevance of the anaerobic digestates composition on potential wettability and contact angle of the soil, we mixed in a laboratory experiment 30 m³ ha-1 of anaerobic digestates derived from mechanically pre-treated substrates from maize and sugar beet with a homogenized Cambic Luvisol. Fourier transform infrared-spectra and diffuse reflectance infrared Fourier transform-spectra of particle intact and finely ground soilanaerobic digestates-mixtures were analyzed to determine the quantities of hydrophobic functional groups in the soil-anaerobic digestates-mixtures that are used here as an indicator for the potential hydrophobicity. The anaerobic digestates application increased the amount of hydrophobic functional groups of the mixtures and reduced the wettability of the soil. However, for intact particle samples an up to threefold higher amount of hydrophobic groups was found as compared to the finely ground ones, indicating a dilution effect of mechanical grinding on the effectivity of the organic matter that is presumably located as a coating on mineral soil particles. For the particle intact samples, the intensity of hydrophobic functional groups bands denoting hydrophobic brickstones in organic matter is indicative for the actual wettability of the soil-anaerobic digestates-mixtures.

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

    PubMed

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

    2007-12-12

    The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF3/methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L(-1). Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices.

  9. Functional groups affect physical and biological properties of dextran-based hydrogels.

    PubMed

    Sun, Guoming; Shen, Yu-I; Ho, Chia Chi; Kusuma, Sravanti; Gerecht, Sharon

    2010-06-01

    Modification of dextran backbone allows the development of a hydrogel with specific characteristics. To enhance their functionality for tissue-engineered scaffolds, a series of dextran-based macromers was synthesized by incorporating various functional groups, including allyl isocyanate (Dex-AI), ethylamine (Dex-AE), chloroacetic acid (Dex-AC), or maleic-anhydride (Dex-AM) into dextrans. The dextran-based biodegradable hybrid hydrogels are developed by integrating polyethylene glycol diacrylate (PEGDA). To explore the effect of different derivatives on hydrogel properties, three different ratios of Dex/PEGDA are examined: low (20/80), medium (40/60), and high (60/40). Differences in physical and biological properties of the hydrogels are found, including swelling, degradation rate, mechanics, crosslinking density, biocompatibility (in vitro and in vivo), and vascular endothelial growth factor release. The results also indicate that the incorporation of amine groups into dextran gives rise to hydrogels with better biocompatible and release properties. We, therefore, conclude that the incorporation of different functional groups affects the fundamental properties of a dextran-based hydrogel network, and that amine groups are preferred to generate hydrogels for biomedical use.

  10. Social skills group training in high-functioning autism: A qualitative responder study.

    PubMed

    Choque Olsson, Nora; Rautio, Daniel; Asztalos, Jenny; Stoetzer, Ulrich; Bölte, Sven

    2016-11-01

    Systematic reviews show some evidence for the efficacy of group-based social skills group training in children and adolescents with autism spectrum disorder, but more rigorous research is needed to endorse generalizability. In addition, little is known about the perspectives of autistic individuals participating in social skills group training. Using a qualitative approach, the objective of this study was to examine experiences and opinions about social skills group training of children and adolescents with higher functioning autism spectrum disorder and their parents following participation in a manualized social skills group training ("KONTAKT"). Within an ongoing randomized controlled clinical trial (NCT01854346) and based on outcome data from the Social Responsiveness Scale, six high responders and five low-to-non-responders to social skills group training and one parent of each child (N = 22) were deep interviewed. Interestingly, both high responders and low-to-non-responders (and their parents) reported improvements in social communication and related skills (e.g. awareness of own difficulties, self-confidence, independence in everyday life) and overall treatment satisfaction, although more positive intervention experiences were expressed by responders. These findings highlight the added value of collecting verbal data in addition to quantitative data in a comprehensive evaluation of social skills group training.

  11. Functional characterization and phylogenetic analysis of acquired and intrinsic macrolide phosphotransferases in the Bacillus cereus group.

    PubMed

    Wang, Chao; Sui, Zhihai; Leclercq, Sébastien Olivier; Zhang, Gang; Zhao, Meilin; Chen, Weiqi; Feng, Jie

    2015-05-01

    The Bacillus cereus group is composed of Gram-positive spore-forming bacteria of clinical and ecological importance. More than 200 B. cereus group isolates have been sequenced. However, there are few reports of B. cereus group antibiotic resistance genes. This study identified two functional classes of macrolide phosphotransferases (Mphs) in the B. cereus group. Cluster A Mphs inactivate 14- and 15-membered macrolides while Cluster B Mphs inactivate 14-, 15- and 16-membered compounds. The genomic region surrounding the Cluster B Mph gene is related to various plasmid sequences, suggesting that this gene is an acquired resistance gene. In contrast, the Cluster A Mph gene is located in a chromosomal region conserved among all B. cereus group isolates, and data indicated that it was acquired early in the evolution of the group. Therefore, the Cluster A gene can be considered an intrinsic resistance gene. However, the gene itself is not present in all strains and our comparative genomics analyses showed that it is exchanged among strains of the B. cereus group by the mean of homologous recombination. These results provide an alternative mechanism to intrinsic resistance.

  12. Effects of functional group mass variance on vibrational properties and thermal transport in graphene

    NASA Astrophysics Data System (ADS)

    Lindsay, L.; Kuang, Y.

    2017-03-01

    Intrinsic thermal resistivity critically depends on features of phonon dispersions dictated by harmonic interatomic forces and masses. Here we present the effects of functional group mass variance on vibrational properties and thermal conductivity (κ ) of functionalized graphene from first-principles calculations. We use graphane, a buckled graphene backbone with covalently bonded hydrogen atoms on both sides, as the base material and vary the mass of the hydrogen atoms to simulate the effect of mass variance from other functional groups. We find nonmonotonic behavior of κ with increasing mass of the functional group and an unusual crossover from acoustic-dominated to optic-dominated thermal transport behavior. We connect this crossover to changes in the phonon dispersion with varying mass which suppress acoustic phonon velocities, but also give unusually high velocity optic modes. Further, we show that out-of-plane acoustic vibrations contribute significantly more to thermal transport than in-plane acoustic modes despite breaking of a reflection-symmetry-based scattering selection rule responsible for their large contributions in graphene. This work demonstrates the potential for manipulation and engineering of thermal transport properties in two-dimensional materials toward targeted applications.

  13. The central role of ketones in reversible and irreversible hydrothermal organic functional group transformations

    NASA Astrophysics Data System (ADS)

    Yang, Ziming; Gould, Ian R.; Williams, Lynda B.; Hartnett, Hilairy E.; Shock, Everett L.

    2012-12-01

    Studies of hydrothermal reactions involving organic compounds suggest complex, possibly reversible, reaction pathways that link functional groups from reduced alkanes all the way to oxidized carboxylic acids. Ketones represent a critical functional group because they occupy a central position in the reaction pathway, at the point where Csbnd C bond cleavage is required for the formation of the more oxidized carboxylic acids. The mechanisms for the critical bond cleavage reactions in ketones, and how they compete with other reactions are the focus of this experimental study. We studied a model ketone, dibenzylketone (DBK), in H2O at 300 °C and 70 MPa for up to 528 h. Product analysis was performed as a function of time at low DBK conversions to reveal the primary reaction pathways. Reversible interconversion between ketone, alcohol, alkene and alkane functional groups is observed in addition to formation of radical coupling products derived from irreversible Csbnd C and Csbnd H homolytic bond cleavage. The product distributions are time-dependent but the bond cleavage products dominate. The major products that accumulate at longer reaction times are toluene and larger, dehydrogenated structures that are initially formed by radical coupling. The hydrogen atoms generated by dehydrogenation of the coupling products are predominantly consumed in the formation of toluene. Even though bond cleavage products dominate, no carboxylic acids were observed on the timescale of the reactions under the chosen experimental conditions.

  14. Nanomechanical characterization of chemical interaction between gold nanoparticles and chemical functional groups.

    PubMed

    Lee, Gyudo; Lee, Hyungbeen; Nam, Kihwan; Han, Jae-Hee; Yang, Jaemoon; Lee, Sang Woo; Yoon, Dae Sung; Eom, Kilho; Kwon, Taeyun

    2012-10-31

    We report on how to quantify the binding affinity between a nanoparticle and chemical functional group using various experimental methods such as cantilever assay, PeakForce quantitative nanomechanical property mapping, and lateral force microscopy. For the immobilization of Au nanoparticles (AuNPs) onto a microscale silicon substrate, we have considered two different chemical functional molecules of amine and catecholamine (here, dopamine was used). It is found that catecholamine-modified surface is more effective for the functionalization of AuNPs onto the surface than the amine-modified surface, which has been shown from our various experiments. The dimensionless parameter (i.e., ratio of binding affinity) introduced in this work from such experiments is useful in quantitatively depicting such binding affinity, indicating that the binding affinity and stability between AuNPs and catecholamine is approximately 1.5 times stronger than that between amine and AuNPs. Our study sheds light on the experiment-based quantitative characterization of the binding affinity between nanomaterial and chemical groups, which will eventually provide an insight into how to effectively design the functional material using chemical groups.

  15. Nanomechanical characterization of chemical interaction between gold nanoparticles and chemical functional groups

    PubMed Central

    2012-01-01

    We report on how to quantify the binding affinity between a nanoparticle and chemical functional group using various experimental methods such as cantilever assay, PeakForce quantitative nanomechanical property mapping, and lateral force microscopy. For the immobilization of Au nanoparticles (AuNPs) onto a microscale silicon substrate, we have considered two different chemical functional molecules of amine and catecholamine (here, dopamine was used). It is found that catecholamine-modified surface is more effective for the functionalization of AuNPs onto the surface than the amine-modified surface, which has been shown from our various experiments. The dimensionless parameter (i.e., ratio of binding affinity) introduced in this work from such experiments is useful in quantitatively depicting such binding affinity, indicating that the binding affinity and stability between AuNPs and catecholamine is approximately 1.5 times stronger than that between amine and AuNPs. Our study sheds light on the experiment-based quantitative characterization of the binding affinity between nanomaterial and chemical groups, which will eventually provide an insight into how to effectively design the functional material using chemical groups. PMID:23113991

  16. Effects of functional group mass variance on vibrational properties and thermal transport in graphene

    DOE PAGES

    Lindsay, L.; Kuang, Y.

    2017-03-13

    Intrinsic thermal resistivity critically depends on features of phonon dispersions dictated by harmonic interatomic forces and masses. We present the effects of functional group mass variance on vibrational properties and thermal conductivity (κ ) of functionalized graphene from first principles calculations. We also use graphane, a buckled graphene backbone with covalently bonded Hydrogen atoms on both sides, as the base material and vary the mass of the Hydrogen atoms to simulate the effect of mass variance from other functional groups. We find non-monotonic behavior of κ with increasing mass of the functional group and an unusual cross-over from acoustic-dominated tomore » optic-dominated thermal transport behavior. We connect this cross-over to changes in the phonon dispersion with varying mass which suppress acoustic phonon velocities, but also give unusually high velocity optic modes. Further, we show that out-of-plane acoustic vibrations contribute significantly more to thermal transport than in-plane acoustic modes despite breaking of a reflection symmetry based scattering selection rule responsible for their large contributions in graphene. Our work demonstrates the potential for manipulation and engineering of thermal transport properties in two dimensional materials toward targeted applications.« less

  17. Reduction of aldehydes and hydrogen cyanide yields in mainstream cigarette smoke using an amine functionalised ion exchange resin

    PubMed Central

    2011-01-01

    Background Cigarette smoking is a well recognized cause of diseases such as lung cancer, chronic obstructive pulmonary disease and cardiovascular disease. Of the more than 5000 identified species in cigarette smoke, at least 150 have toxicological activity. For example, formaldehyde and acetaldehyde have been assigned as Group 1 and Group 2B carcinogens by IARC, and hydrogen cyanide has been identified as a respiratory and cardiovascular toxicant. Active carbon has been shown to be an effective material for the physical adsorption of many of the smoke volatile species. However, physical adsorption of acetaldehyde, formaldehyde and also hydrogen cyanide from smoke is less effective using carbon. Alternative methods for the removal of these species from cigarette smoke are therefore of interest. A macroporous, polystyrene based ion-exchange resin (Diaion®CR20) with surface amine group functionality has been investigated for its ability to react with aldehydes and HCN in an aerosol stream, and thus selectively reduce the yields of these compounds (in particular formaldehyde) in mainstream cigarette smoke. Results Resin surface chemistry was characterized using vapour sorption, XPS, TOF-SIMS and 15N NMR. Diaion®CR20 was found to have structural characteristics indicating weak physisorption properties, but sufficient surface functionalities to selectively remove aldehydes and HCN from cigarette smoke. Using 60 mg of Diaion®CR20 in a cigarette cavity filter gave reductions in smoke formaldehyde greater than 50% (estimated to be equivalent to >80% of the formaldehyde present in the smoke vapour phase) independent of a range of flow rates. Substantial removal of HCN (>80%) and acetaldehyde (>60%) was also observed. The performance of Diaion®CR20 was found to be consistent over a test period of 6 months. The overall adsorption for the majority of smoke compounds measured appeared to follow a pseudo-first order approximation to second order kinetics. Conclusions This

  18. Wetland macroinvertebrates of Prentiss Bay, Lake Huron, Michigan: diversity and functional group composition

    USGS Publications Warehouse

    Merritt, R.W.; Benbow, M.E.; Hudson, P.L.

    2002-01-01

    The Great Lakes support many fish and waterbirds that depend directly or indirectly on coastal wetlands during some portion of their life cycle. It is known that macroinvertebrates make up an important part of wetland food webs and ecosystem function; however, our understanding of species distribution within and among wetlands has only recently received attention. We investigated the macroinvertebrates of a freshwater marsh (Prentiss Bay) in the Les Chenaux Island Area of Northern Lake Huron, Michigan. Macroinvertebrate taxa diversity and functional feeding group composition were compared between two habitats. A shallow depositional habitat with higher vegetation diversity and little wave action was compared to a deeper erosional habitat with fewer plant species and more wave action. A total of 83 taxa were collected over the summer of 1996, representing two phyla (Arthropoda and Mollusca) and five classes (Arachnida, Bivalvia, Malacostraca, Gastropoda and Insecta). A total of 79 genera were identified, with 92% being insects (39 families composed of at least 73 genera). Of the total, 42 insect genera were common to both habitats,while relatively fewer were collected exclusively from the erosional compared the depositional habitat. When habitats were pooled, predators comprised about 50% of the functional group taxa, while gathering collectors and shredders each were about 20%. Filtering collectors and scrapers each represented < 10%. When comparing habitats, there was a relatively higher percentage of predators and shredders in the depositional habitat, while all other functional groups were lower. These data suggest that vegetation diversity, depth and wave action affect taxa composition and functional group organization of the Prentiss Bay marsh.

  19. Functionality of In vitro Reconstituted Group II Intron RmInt1-Derived Ribonucleoprotein Particles.

    PubMed

    Molina-Sánchez, Maria D; García-Rodríguez, Fernando M; Toro, Nicolás

    2016-01-01

    The functional unit of mobile group II introns is a ribonucleoprotein particle (RNP) consisting of the intron-encoded protein (IEP) and the excised intron RNA. The IEP has reverse transcriptase activity but also promotes RNA splicing, and the RNA-protein complex triggers site-specific DNA insertion by reverse splicing, in a process called retrohoming. In vitro reconstituted ribonucleoprotein complexes from the Lactococcus lactis group II intron Ll.LtrB, which produce a double strand break, have recently been studied as a means of developing group II intron-based gene targeting methods for higher organisms. The Sinorhizobium meliloti group II intron RmInt1 is an efficient mobile retroelement, the dispersal of which appears to be linked to transient single-stranded DNA during replication. The RmInt1IEP lacks the endonuclease domain (En) and cannot cut the bottom strand to generate the 3' end to initiate reverse transcription. We used an Escherichia coli expression system to produce soluble and active RmInt1 IEP and reconstituted RNPs with purified components in vitro. The RNPs generated were functional and reverse-spliced into a single-stranded DNA target. This work constitutes the starting point for the use of group II introns lacking DNA endonuclease domain-derived RNPs for highly specific gene targeting methods.

  20. Control of oxo-group functionalization and reduction of the uranyl ion.

    PubMed

    Arnold, Polly L; Pécharman, Anne-Frédérique; Lord, Rianne M; Jones, Guy M; Hollis, Emmalina; Nichol, Gary S; Maron, Laurent; Fang, Jian; Davin, Thomas; Love, Jason B

    2015-04-06

    Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, "Pacman" geometry that stabilizes the U(V) oxidation state and promotes chemistry at a single uranyl oxo-group. We present here new and straightforward routes to singly reduced and oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one oxo-group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both oxo-groups are Mg functionalized as a result of Mg-N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U-O-Zn dative interactions, leading to reductive silylation of the uranyl oxo-group in preference to metalation. Spectroscopic, crystallographic, and computational analysis of these reactions and of oxo-metalated products isolated by other routes have allowed us to propose mechanisms that account for pathways to metalation or silylation of the exo-oxo-group.

  1. Functionality of In vitro Reconstituted Group II Intron RmInt1-Derived Ribonucleoprotein Particles

    PubMed Central

    Molina-Sánchez, Maria D.; García-Rodríguez, Fernando M.; Toro, Nicolás

    2016-01-01

    The functional unit of mobile group II introns is a ribonucleoprotein particle (RNP) consisting of the intron-encoded protein (IEP) and the excised intron RNA. The IEP has reverse transcriptase activity but also promotes RNA splicing, and the RNA-protein complex triggers site-specific DNA insertion by reverse splicing, in a process called retrohoming. In vitro reconstituted ribonucleoprotein complexes from the Lactococcus lactis group II intron Ll.LtrB, which produce a double strand break, have recently been studied as a means of developing group II intron-based gene targeting methods for higher organisms. The Sinorhizobium meliloti group II intron RmInt1 is an efficient mobile retroelement, the dispersal of which appears to be linked to transient single-stranded DNA during replication. The RmInt1IEP lacks the endonuclease domain (En) and cannot cut the bottom strand to generate the 3′ end to initiate reverse transcription. We used an Escherichia coli expression system to produce soluble and active RmInt1 IEP and reconstituted RNPs with purified components in vitro. The RNPs generated were functional and reverse-spliced into a single-stranded DNA target. This work constitutes the starting point for the use of group II introns lacking DNA endonuclease domain-derived RNPs for highly specific gene targeting methods. PMID:27730127

  2. Unification of [FeFe]-hydrogenases into three structural and functional groups

    DOE PAGES

    Poudel, Saroj; Tokmina-Lukaszewska, Monika; Colman, Daniel R.; ...

    2016-05-27

    [FeFe]-hydrogenases (Hyd) are structurally diverse enzymes that catalyze the reversible oxidation of hydrogen (H2). Recent biochemical data demonstrate new functional roles for these enzymes, including those that function in electron bifurcation where an exergonic reaction is coupled with an endergonic reaction to drive the reversible oxidation/production of H2. To identify the structural determinants that underpin differences in enzyme functionality, a total of 714 homologous sequences of the catalytic subunit, HydA, were compiled. Bioinformatics approaches informed by biochemical data were then used to characterize differences in inferred quaternary structure, HydA active site protein environment, accessory iron-sulfur clusters in HydA, and regulatorymore » proteins encoded in HydA gene neighborhoods. HydA homologs were clustered into one of three classification groups, Group 1 (G1), Group 2 (G2), and Group 3 (G3). G1 enzymes were predicted to be monomeric while those in G2 and G3 were predicted to be multimeric and include HydB, HydC (G2/G3) and HydD (G3) subunits. Variation in the HydA active site and accessory iron-sulfur clusters did not vary by group type. Group-specific regulatory genes were identified in the gene neighborhoods of both G2 and G3 Hyd. Analyses of purified G2 and G3 enzymes by mass spectrometry strongly suggests that they are post-translationally modified by phosphorylation. In conclusion, these results suggest that bifurcation capability is dictated primarily by the presence of both HydB and HydC in Hyd complexes, rather than by variation in HydA.« less

  3. Unification of [FeFe]-hydrogenases into three structural and functional groups

    SciTech Connect

    Poudel, Saroj; Tokmina-Lukaszewska, Monika; Colman, Daniel R.; Refai, Mohammed; Schut, Gerrit J.; King, Paul W.; Maness, Pin-Ching; Adams, Michael W. W.; Peters, John W.; Bothner, Brian; Boyd, Eric S.

    2016-05-27

    [FeFe]-hydrogenases (Hyd) are structurally diverse enzymes that catalyze the reversible oxidation of hydrogen (H2). Recent biochemical data demonstrate new functional roles for these enzymes, including those that function in electron bifurcation where an exergonic reaction is coupled with an endergonic reaction to drive the reversible oxidation/production of H2. To identify the structural determinants that underpin differences in enzyme functionality, a total of 714 homologous sequences of the catalytic subunit, HydA, were compiled. Bioinformatics approaches informed by biochemical data were then used to characterize differences in inferred quaternary structure, HydA active site protein environment, accessory iron-sulfur clusters in HydA, and regulatory proteins encoded in HydA gene neighborhoods. HydA homologs were clustered into one of three classification groups, Group 1 (G1), Group 2 (G2), and Group 3 (G3). G1 enzymes were predicted to be monomeric while those in G2 and G3 were predicted to be multimeric and include HydB, HydC (G2/G3) and HydD (G3) subunits. Variation in the HydA active site and accessory iron-sulfur clusters did not vary by group type. Group-specific regulatory genes were identified in the gene neighborhoods of both G2 and G3 Hyd. Analyses of purified G2 and G3 enzymes by mass spectrometry strongly suggests that they are post-translationally modified by phosphorylation. In conclusion, these results suggest that bifurcation capability is dictated primarily by the presence of both HydB and HydC in Hyd complexes, rather than by variation in HydA.

  4. Functional groups in the social behavior of a cichlid fish, the Oscar, Astronotus ocellatus.

    PubMed

    Beeching, S C

    1997-01-01

    Dummy conspecifics were presented to isolated adults of the cichlid fish Astronotus ocellatus to investigate the functional organization of cichlid social behavior. Body size and 15 dummy-elicited activities were recorded during 15 min sessions and analyzed by principal components analysis (PCA) to reveal their temporal organization. Five principal components explained almost 80% of the variation in dummy-elicited behavior, and these five factors define functional groups for Nest-oriented and attack modal action patterns are not mutually inhibitory during this time frame, and biting does not appear to function exclusively during an attack on a conspecific. Comparison with previous studies of New and Old World cichlids suggests evolutionary conservation of the functional organization of social behavior.

  5. Species, Guilds, and Functional Groups: Taxonomy and Behavior in Nematophagous Arthropods

    PubMed Central

    Walter, David Evans; Ikonen, Eeva K.

    1989-01-01

    Phylogenetic relationship is an indication of shared abilities, or at least of shared constraints, on morphology, physiology, and behavior; but is phylogenetic relationship a sufficient criterion for predicting ecological function? Ecologists have assumed that the function of invertebrates in soil systems can be predicted at a low level of taxonomic resolution, but our research indicates that critical functional parameters -- e.g., feeding behavior, developmental rate, and reproductive mode -- are rarely predictable above the generic level. Since morphology is more strongly conserved than behavior, feeding guilds or functional groups based on broad taxonomic relationship or untested assumptions about correlations between trophic morphology and feeding behavior have little meaning for nematophagous arthropods from grassland soils in Colorado. PMID:19287615

  6. Group analysis of self-organizing maps based on functional MRI using restricted Frechet means

    PubMed Central

    Fournel, Arnaud P.; Reynaud, Emanuelle; Brammer, Michael J.; Simmons, Andrew; Ginestet, Cedric E.

    2013-01-01

    Studies of functional MRI data are increasingly concerned with the estimation of differences in spatio-temporal networks across groups of subjects or experimental conditions. Unsupervised clustering and independent component analysis (ICA) have been used to identify such spatio-temporal networks. While these approaches have been useful for estimating these networks at the subject-level, comparisons over groups or experimental conditions require further methodological development. In this paper, we tackle this problem by showing how self-organizing maps (SOMs) can be compared within a Frechean inferential framework. Here, we summarize the mean SOM in each group as a Frechet mean with respect to a metric on the space of SOMs. The advantage of this approach is twofold. Firstly, it allows the visualization of the mean SOM in each experimental condition. Secondly, this Frechean approach permits one to draw inference on group differences, using permutation of the group labels. We consider the use of different distance functions, and introduce one extension of the classical sum of minimum distance (SMD) between two SOMs, which take into account the spatial pattern of the fMRI data. The validity of these methods is illustrated on synthetic data. Through these simulations, we show that the two distance functions of interest behave as expected, in the sense that the ones capturing temporal and spatial aspects of the SOMs are more likely to reach significance under simulated scenarios characterized by temporal, spatial [and spatio-temporal] differences, respectively. In addition, a re-analysis of a classical experiment on visually-triggered emotions demonstrates the usefulness of this methodology. In this study, the multivariate functional patterns typical of the subjects exposed to pleasant and unpleasant stimuli are found to be more similar than the ones of the subjects exposed to emotionally neutral stimuli. In this re-analysis, the group-level SOM output units with the

  7. Compatibility of functional groups in K[sup ow]-based QSARs: Application to nitro compounds

    SciTech Connect

    Banerjee, S.; Williams, C.L. )

    1993-10-01

    Nitro compounds are particular difficult to handle in simple K[sup ow]-based QSARs, owing to differences in their lipid-phase activity coefficients. These differences can be corrected, in part, through inclusion of a term in octanol solubility. A procedure for identifying potentially incompatible groups in a given QSAR is suggested. The quality of a QSAR is best if the interactions of the functional groups involved with octanol fall within a narrow range. These interactions are easily calculated by the UNIFAC method.

  8. Preparation of 1-C-glycosyl aldehydes by reductive hydrolysis.

    PubMed

    Sipos, Szabolcs; Jablonkai, István

    2011-09-06

    Reductive hydrolysis of various protected glycosyl cyanides was carried out using DIBAL-H to form aldimine alane intermediates which were then hydrolyzed under mildly acidic condition to provide the corresponding aldehyde derivatives. While 1-C-formyl glycal and 2-deoxy glycosyl derivatives were stable during isolation and storage 1-C-glycosyl formaldehydes in the gluco, galacto and manno series were sensitive and decomposition occurred by 2-alkyloxy elimination. A one-pot method using N,N'-diphenylethylenediamine to trap these aldehydes in stable form was developed. Reductive hydrolysis of glycosyl cyanides offers valuable aldehyde building blocks in a convenient way which can be applied in the synthesis of complex C-glycosides.

  9. An Application of Functional Renormalization Group Method for Superdense Nuclear Matter

    NASA Astrophysics Data System (ADS)

    Barnaföldi, G. G.; Jakovác, A.; Pósfay, P.

    2017-01-01

    We proposed a method, using the expansion of the effective potential in a base of harmonic functions, to study the Functional Renormalization Group (FRG) method at finite chemical potential. Within this theoretical framework we determined the equation of state and the phase diagram of a simple model of massless fermions coupled to scalars through Yukawa-couling at the zero-temperature limit. Here, we use our FRG-based equation of state to describe the superdense nuclear matter inside compact astrophysical objects. We calculated the mass-radius relation for a compact star using the TOV equation, which was compared to other results.

  10. Universal short-time dynamics: Boundary functional renormalization group for a temperature quench

    NASA Astrophysics Data System (ADS)

    Chiocchetta, Alessio; Gambassi, Andrea; Diehl, Sebastian; Marino, Jamir

    2016-11-01

    We present a method to calculate short-time nonequilibrium universal exponents within the functional-renormalization-group scheme. As an example, we consider the classical critical dynamics of the relaxational model A after a quench of the temperature of the system and calculate the initial-slip exponent which characterizes the nonequilibrium universal short-time behavior of both the order parameter and correlation functions. The value of this exponent is found to be consistent with the result of a perturbative dimensional expansion and of Monte Carlo simulations in three spatial dimensions.

  11. N-containing functional groups induced superior cytocompatible and hemocompatible graphene by NH₂ ion implantation.

    PubMed

    Guo, Meixian; Li, Minsi; Liu, Xiaoqi; Zhao, Mengli; Li, Dejun; Geng, Dongsheng; Sun, Xueliang; Gu, Hanqing

    2013-12-01

    Graphene is functionalized with amine by NH2 ion implantation at room temperature in vacuum. The reaction is featured by nucleophilic substitution of C-O groups by the ammonia radicals. The presence of N-containing functional groups in graphene is identified by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. N element was successfully introduced to graphene, the atomic ratio of N to C rose to 3.12 %. NH2 ion implanted graphene (G-NH2) is a better hydrophilic material than pristine grahene according to the contact angle experiment. Mouse fibroblast cells and human endothelial cells cultured on G-NH2 displayed superior cell-viability, proliferation and stretching over that on pristine graphene. Platelet adhesion, hemolysis and Kinetic-clotting time were measured on G-NH2, showing excellent anticoagulation, with as good hemolysis as pristine graphene.

  12. Preparation and properties of a novel biodegradable polyester elastomer with functional groups.

    PubMed

    Liu, Quan-Yong; Wu, Si-Zhu; Tan, Tian-Wei; Weng, Jing-Yi; Zhang, Li-Qun; Liu, Li; Tian, Wei; Chen, Da-Fu

    2009-01-01

    A novel biodegradable poly(sebacate-glycerol-citrate) (PGSC) elastomer with functional groups was prepared in this study. First, moldable mixtures were obtained by mixing citric acid with the poly(glycerol-sebacate) (PGS) pre-polymers synthesized in our lab. The PGSC elastomers were obtained from moldable mixtures that were thermally cured in the moulds. Then, the structures, compositions and properties of the elastomers were studied by Fourier transformation infrared spectroscopy (FT-IR), swelling test, differential scanning calorimeter (DSC), tensile test, water contact angle measurement, water absorption experiments and a in vitro degradation test. It showed that the hydroxyl groups remained in the elastomers which would endow the polymer chains with functionality such as good surface modification. By controlling the thermal curing time, the compositions of the PGSC elastomers were adjusted for different mechanical and biodegradable properties. Therefore, PGSC elastomers might be used as anti-conglutination films in surgery, guided tissue regeneration membranes and drug-delivery matrices.

  13. Approaching many-body localization from disordered Luttinger liquids via the functional renormalization group

    NASA Astrophysics Data System (ADS)

    Karrasch, C.; Moore, J. E.

    2015-09-01

    We study the interplay of interactions and disorder in a one-dimensional fermion lattice coupled adiabatically to infinite reservoirs. We employ both the functional renormalization group (FRG) as well as matrix product state techniques, which serve as an accurate benchmark for small systems. Using the FRG, we compute the length- and temperature-dependence of the conductance averaged over 104 samples for lattices as large as 105 sites. We identify regimes in which non-Ohmic power law behavior can be observed and demonstrate that the corresponding exponents can be understood by adapting earlier predictions obtained perturbatively for disordered Luttinger liquids. In the presence of both disorder and isolated impurities, the conductance has a universal single-parameter scaling form. This lays the groundwork for an application of the functional renormalization group to the realm of many-body localization.

  14. How surface functional groups influence fracturation in nanofluids droplets dry-outs

    NASA Astrophysics Data System (ADS)

    Brutin, David; Carle, Florian

    2012-11-01

    We report an experimental investigation of the drying of a deposited droplets of nanofluids with different surface functional groups. For identical nano-particles diameter, material and concentration, identical drying conditions, the substrate and the functional groups at the nano-particles surface are changed. Both flow motion, adhesion, gelation and fracturation occur during the evaporation of this complex matter leading to different final typical patterns. The differences in between the patterns are explained based on the surface chemical potential. Crack shapes and wavelengths are globally proportional to the electrical charges carried at the nano- particles surface which is a new parameter to implement in existing predicting models. Presently only the colloid concentration and softness and the deposit thickness are used (Allain and Limat, 1995). The authors gratefully acknowledge the help and the fruitful discussions raised with J.B. Lang.

  15. Assemblage patterns of fish functional groups relative to habitat connectivity and conditions in floodplain lakes

    USGS Publications Warehouse

    Miyazono, S.; Aycock, J.N.; Miranda, L.E.; Tietjen, T.E.

    2010-01-01

    We evaluated the influences of habitat connectivity and local environmental factors on the distribution and abundance patterns of fish functional groups in 17 floodplain lakes in the Yazoo River Basin, USA. The results of univariate and multivariate analyses showed that species-environmental relationships varied with the functional groups. Species richness and assemblage structure of periodic strategists showed strong and positive correlations with habitat connectivity. Densities of most equilibrium and opportunistic strategists decreased with habitat connectivity. Densities of certain equilibrium and opportunistic strategists increased with turbidity. Forested wetlands around the lakes were positively related to the densities of periodic and equilibrium strategists. These results suggest that decreases in habitat connectivity, forested wetland buffers and water quality resulting from environmental manipulations may cause local extinction of certain fish taxa and accelerate the dominance of tolerant fishes in floodplain lakes. ?? 2010 John Wiley & Sons A/S.

  16. The Donaldson-Witten Function for Gauge Groups of Rank Larger Than One

    NASA Astrophysics Data System (ADS)

    Mariño, Marcos; Moore, Gregory

    We study correlation functions in topologically twisted , d=4 supersymmetric Yang-Mills theory for gauge groups of rank larger than one on compact four-manifolds X. We find that the topological invariance of the generator of correlation functions of BRST invariant observables is not spoiled by noncompactness of field space. We show how to express the correlators on simply connected manifolds of b2,+(X)>0 in terms of Seiberg-Witten invariants and the classical cohomology ring of X. For manifolds X of simple type and gauge group SU(N) we give explicit expressions of the correlators as a sum over =1 vacua. We describe two applications of our expressions, one to superconformal field theory and one to large N expansions of SU(N) , d=4 supersymmetric Yang-Mills theory.

  17. Synthesis and physicochemical properties of polysiloxane functionalized with aminoacetic acid groups

    NASA Astrophysics Data System (ADS)

    Lakiza, N. V.; Neudachina, L. K.

    2016-07-01

    Polysiloxane functionalized with aminoacetic acid groups was synthesized using sol-gel technology. Elemental analysis and FTIR spectroscopy were used to determine the composition of the polysiloxane show that it is a mesoporous material with a developed surface (109.4 m2/g). It was found that the selective properties of carboxymethylated polysiloxane towards transition metal ions simultaneously present in an ammonium acetate solution change in the order Zn < Cu > Ni > Co > Pb > Cd. It was shown that the sorption of copper(II) ions by carboxymethylated aminopropylpolysiloxane with particle sizes of 50-71 μm reaches its maximum level within 2 h; the rate-limiting step of the process is the chemical reaction between the ions and the polysiloxane functional groups; and the pseudo-second-order model is the best way of describing sorption.

  18. Preconversion catalytic deoxygenation of phenolic functional groups. Quarterly report, January 1--March 30, 1996

    SciTech Connect

    Kubiak, C.P.

    1996-12-31

    Over the course of the studies on catalytic deoxygenation of phenolic residues in coal by carbon monoxide, the author performed preliminary investigations into the removal of other heteroatom groups. This report describes the attempted carbonylation of phenyl amido complexes. These studies resulted in the surprisingly facile formation of amidines. The amidine group is the nitrogen analog of carboxylic acids and esters. This functional group combines the properties of an azomethane-like C=N double bond with an amide-like C-N single bond. This group, like the related allyl (C-C-C), aza-allyl (C-N-C), and carboxylato (O-C-O) groups, form a number of transition metal derivatives, with both early and late transition metals. Various bonding modes of the amidino group have been reported. However, most isolated complexes have the amidino ligand as a chelating ligand or bridging two metals. This is due to the preference of amidines to bond via the nitrogen lone pairs, in contrast to the {eta}3 bonding observed in metal-allyl complexes. The experimental section of the paper describes the synthesis of platinum complexes, X-ray diffraction data for one Pt complex, and its reaction with carbon monoxide. Results are presented on the crystal and molecular structure of a platinum complex.

  19. Temporal lobe contribution to perceptual function: A tale of three patient groups.

    PubMed

    Behrmann, M; Lee, A C H; Geskin, J Z; Graham, K S; Barense, M D

    2016-09-01

    There has been growing recognition of the contribution of medial and anterior temporal lobe structures to non-mnemonic functions, such as perception. To evaluate the nature of this contribution, we contrast the perceptual performance of three patient groups, all of whom have a perturbation of these temporal lobe structures. Specifically, we compare the profile of patients with focal hippocampal (HC) lesions, those with more extensive lesions to the medial temporal lobe (MTL) that include HC and perirhinal cortex (PrC), and those with congenital prosopagnosia (CP), whose deficit has been attributed to the disconnection of the anterior temporal lobe from more posterior structures. All participants completed a range of'oddity' tasks in which, on each trial, they determined which of four visual stimuli in a display was the'odd-one-out'. There were five stimulus categories including faces, scenes, objects (high and low ambiguity) and squares of different sizes. Comparisons were conducted separately for the HC, MTL and CP groups against their matched control groups and then the group data were compared to each other directly. The group profiles were easily differentiable. Whereas the HC group stood out for its difficulty in discriminating scenes and the CP group stood out for its disproportionate difficulty in discriminating faces with milder effects for scenes and high ambiguity objects, the MTL group evinced a more general discrimination deficit for faces, scenes and high ambiguity objects. The group differences highlight distinct profiles for each of the three groups and distinguish the signature perceptual impairments following more extended temporal lobe alterations. In the recent reconsideration of the role of the hippocampus and neocortex, Moscovitch and colleagues (Moscovitch et al., 2016) note that the medial temporal lobe structures play a role in non-mnemonic functions, such as perception, problem solving, decision-making and language. Here, we address this

  20. β-Diversity of functional groups of woody plants in a tropical dry forest in Yucatan.

    PubMed

    López-Martínez, Jorge Omar; Sanaphre-Villanueva, Lucía; Dupuy, Juan Manuel; Hernández-Stefanoni, José Luis; Meave, Jorge Arturo; Gallardo-Cruz, José Alberto

    2013-01-01

    Two main theories have attempted to explain variation in plant species composition (β-diversity). Niche theory proposes that most of the variation is related to environment (environmental filtering), whereas neutral theory posits that dispersal limitation is the main driver of β-diversity. In this study, we first explored how α- and β-diversity of plant functional groups defined by growth form (trees, shrubs and lianas, which represent different strategies of resource partitioning), and dispersal syndrome (autochory, anemochory and zoochory, which represent differences in dispersal limitation) vary with successional age and topographic position in a tropical dry forest. Second, we examined the effects of environmental, spatial, and spatially-structured environmental factors on β-diversity of functional groups; we used the spatial structure of sampling sites as a proxy for dispersal limitation, and elevation, soil properties and forest stand age as indicators of environmental filtering. We recorded 200 species and 22,245 individuals in 276 plots; 120 species were trees, 41 shrubs and 39 lianas. We found that β-diversity was highest for shrubs, intermediate for lianas and lowest for trees, and was slightly higher for zoochorous than for autochorous and anemochorous species. All three dispersal syndromes, trees and shrubs varied in composition among vegetation classes (successional age and topographic position), whilst lianas did not. β-diversity was influenced mostly by proxies of environmental filtering, except for shrubs, for which the influence of dispersal limitation was more important. Stand age and topography significantly influenced α-diversity across functional groups, but showed a low influence on β-diversity -possibly due to the counterbalancing effect of resprouting on plant distribution and composition. Our results show that considering different plant functional groups reveals important differences in both α- and β-diversity patterns and

  1. β-Diversity of Functional Groups of Woody Plants in a Tropical Dry Forest in Yucatan

    PubMed Central

    López-Martínez, Jorge Omar; Sanaphre-Villanueva, Lucía; Dupuy, Juan Manuel; Hernández-Stefanoni, José Luis; Meave, Jorge Arturo; Gallardo-Cruz, José Alberto

    2013-01-01

    Two main theories have attempted to explain variation in plant species composition (β-diversity). Niche theory proposes that most of the variation is related to environment (environmental filtering), whereas neutral theory posits that dispersal limitation is the main driver of β-diversity. In this study, we first explored how α- and β-diversity of plant functional groups defined by growth form (trees, shrubs and lianas, which represent different strategies of resource partitioning), and dispersal syndrome (autochory, anemochory and zoochory, which represent differences in dispersal limitation) vary with successional age and topographic position in a tropical dry forest. Second, we examined the effects of environmental, spatial, and spatially-structured environmental factors on β-diversity of functional groups; we used the spatial structure of sampling sites as a proxy for dispersal limitation, and elevation, soil properties and forest stand age as indicators of environmental filtering. We recorded 200 species and 22,245 individuals in 276 plots; 120 species were trees, 41 shrubs and 39 lianas. We found that β-diversity was highest for shrubs, intermediate for lianas and lowest for trees, and was slightly higher for zoochorous than for autochorous and anemochorous species. All three dispersal syndromes, trees and shrubs varied in composition among vegetation classes (successional age and topographic position), whilst lianas did not. β-diversity was influenced mostly by proxies of environmental filtering, except for shrubs, for which the influence of dispersal limitation was more important. Stand age and topography significantly influenced α-diversity across functional groups, but showed a low influence on β-diversity –possibly due to the counterbalancing effect of resprouting on plant distribution and composition. Our results show that considering different plant functional groups reveals important differences in both α- and β-diversity patterns and

  2. Organic Mass Fragments and Organic Functional Groups in Aged Biomass Burning and Fossil Fuel Combustion Aerosol

    NASA Astrophysics Data System (ADS)

    Day, D. A.; Hawkins, L. N.; Russell, L. M.

    2009-12-01

    Organic functional group concentrations in submicron aerosol particles collected from 27 June to 17 September at the Scripps Pier in La Jolla, California as part of AeroSCOPE 2008 were quantified using Fourier Transform Infrared (FTIR) spectroscopy. Organic and inorganic non-refractory components in the same air masses were quantified using a Quadrupole Aerosol Mass Spectrometer (Q-AMS). Previous measurements at the Scripps pier indicate that a large fraction of submicron particle mass originates in Los Angeles and the port of Long Beach. Additional particle sources to the region include local urban emissions and periodic biomass burning during large wildfires. Three distinct types of organic aerosol components were identified from organic composition and elemental tracers, including biomass burning, fossil fuel combustion, and polluted marine components. Fossil fuel combustion organic aerosol was dominated by unsaturated alkane and was correlated with sulfur, vanadium, and nickel supporting ship and large trucks in and around the Los Angeles/Long Beach region as the dominant source. Biomass burning organic aerosol comprised a smaller unsaturated alkane fraction and larger fractions of non-acid carbonyl, amine, and carboxylic acid and was correlated with potassium and bromine. Polluted marine organic aerosol was dominated by organic hydroxyl and unsaturated alkane and was not correlated with any elemental tracers. Mass spectra of the organic aerosol support the aerosol sources determined by organic functional groups and elemental tracers and contain fragments commonly attributed to oxygenated organic aerosol (OOA), hydrocarbon-like organic aerosol (HOA), and biomass burning organic aerosol (BBOA). Comparisons of the PMF-derived Q-AMS source spectra with FTIR source spectra and functional group composition provide additional information on the relationship between commonly reported organic aerosol factors and organic functional groups in specific organic aerosol

  3. Harmonic expansion of the effective potential in a functional renormalization group at finite chemical potential

    NASA Astrophysics Data System (ADS)

    Barnaföldi, G. G.; Jakovác, A.; Pósfay, P.

    2017-01-01

    In this paper we propose a method to study the functional renormalization group (FRG) at finite chemical potential. The method consists of mapping the FRG equations within the Fermi surface into a differential equation defined on a rectangle with zero boundary conditions. To solve this equation we use an expansion of the potential in a harmonic basis. With this method we determined the phase diagram of a simple Yukawa-type model; as expected, the bosonic fluctuations decrease the strength of the transition.

  4. Isgur-Wise functions and unitary representations of the Lorentz group: The baryon case j=0

    SciTech Connect

    Le Yaouanc, A.; Oliver, L.; Raynal, J.-C.

    2009-09-01

    We propose a group theoretical method to study Isgur-Wise (IW) functions. A current matrix element splits into a heavy quark matrix element and an overlap of the initial and final clouds, related to the IW functions, that contain the long distance physics. The light cloud belongs to the Hilbert space of a unitary representation of the Lorentz group. Decomposing into irreducible representations one obtains the IW function as an integral formula, superposition of irreducible IW functions with positive measures, providing positivity bounds on its derivatives. Our method is equivalent to the sum rule approach, but sheds another light on the physics and summarizes and gives all its possible constraints. We expose the general formalism, thoroughly applying it to the case j=0 for the light cloud, relevant to the semileptonic decay {lambda}{sub b}{yields}{lambda}{sub c}l{nu}{sub l}. In this case, the principal series of the representations contribute, and also the supplementary series. We recover the bound for the curvature of the j=0 IW function {xi}{sub {lambda}}(w) that we did obtain from the sum rule method, and we get new bounds for higher derivatives. We demonstrate also that if the lower bound for the curvature is saturated, then {xi}{sub {lambda}}(w) is completely determined, given by an explicit elementary function. We give criteria to decide if any Ansatz for the Isgur-Wise function is compatible or not with the sum rules. We apply the method to some simple model forms proposed in the literature. Dealing with a Hilbert space, the sum rules are convergent, but this feature does not survive hard gluon radiative corrections.

  5. Biodegradable polyglycerols with randomly distributed ketal groups as multi-functional drug delivery systems.

    PubMed

    Shenoi, Rajesh A; Lai, Benjamin F L; Imran ul-haq, Muhammad; Brooks, Donald E; Kizhakkedathu, Jayachandran N

    2013-08-01

    Biodegradable multi-functional polymeric nanostructures that undergo controlled degradation in response to physiological cues are important in numerous biomedical applications including drug delivery, bio-conjugation and tissue engineering. In this paper, we report the development of a new class of water soluble multi-functional branched biodegradable polymer with high molecular weight and biocompatibility which demonstrates good correlation of in vivo biodegradation and in vitro hydrolysis. Main chain degradable hyperbranched polyglycerols (HPG) (20-100 kDa) were synthesized by the introduction of acid labile groups within the polymer structure by an anionic ring opening copolymerization of glycidol with ketal-containing epoxide monomers with different ketal structures. The water soluble biodegradable HPGs with randomly distributed ketal groups (RBHPGs) showed controlled degradation profiles in vitro depending on the pH of solution, temperature and the structure of incorporated ketal groups, and resulted in non-toxic degradation products. NMR studies demonstrated the branched nature of RBHPGs which is correlating with their smaller hydrodynamic radii. The RBHPGs and their degradation products exhibited excellent blood compatibility and tissue compatibility based on various analyses methods, independent of their molecular weight and ketal group structure. When administered intravenously in mice, tritium labeled RBHPG of molecular weight 100 kDa with dimethyl ketal group showed a circulation half life of 2.7 ± 0.3 h, correlating well with the in vitro polymer degradation half life (4.3 h) and changes in the molecular weight profile during the degradation (as measured by gel permeation chromatography) in buffer conditions at 37 °C. The RBHPG degraded into low molecular weight fragments that were cleared from circulation rapidly. The biodistribution and excretion studies demonstrated that RBHPG exhibited significantly lower tissue accumulation and enhanced urinary

  6. Small functional groups for controlled differentiation of hydrogel-encapsulated human mesenchymal stem cells

    NASA Astrophysics Data System (ADS)

    Benoit, Danielle S. W.; Schwartz, Michael P.; Durney, Andrew R.; Anseth, Kristi S.

    2008-10-01

    Cell-matrix interactions have critical roles in regeneration, development and disease. The work presented here demonstrates that encapsulated human mesenchymal stem cells (hMSCs) can be induced to differentiate down osteogenic and adipogenic pathways by controlling their three-dimensional environment using tethered small-molecule chemical functional groups. Hydrogels were formed using sufficiently low concentrations of tether molecules to maintain constant physical characteristics, encapsulation of hMSCs in three dimensions prevented changes in cell morphology, and hMSCs were shown to differentiate in normal growth media, indicating that the small-molecule functional groups induced differentiation. To our knowledge, this is the first example where synthetic matrices are shown to control induction of multiple hMSC lineages purely through interactions with small-molecule chemical functional groups tethered to the hydrogel material. Strategies using simple chemistry to control complex biological processes would be particularly powerful as they could make production of therapeutic materials simpler, cheaper and more easily controlled.

  7. Functional group-specific traits drive phytoplankton dynamics in the oligotrophic ocean.

    PubMed

    Alexander, Harriet; Rouco, Mónica; Haley, Sheean T; Wilson, Samuel T; Karl, David M; Dyhrman, Sonya T

    2015-11-03

    A diverse microbial assemblage in the ocean is responsible for nearly half of global primary production. It has been hypothesized and experimentally demonstrated that nutrient loading can stimulate blooms of large eukaryotic phytoplankton in oligotrophic systems. Although central to balancing biogeochemical models, knowledge of the metabolic traits that govern the dynamics of these bloom-forming phytoplankton is limited. We used eukaryotic metatranscriptomic techniques to identify the metabolic basis of functional group-specific traits that may drive the shift between net heterotrophy and autotrophy in the oligotrophic ocean. Replicated blooms were simulated by deep seawater (DSW) addition to mimic nutrient loading in the North Pacific Subtropical Gyre, and the transcriptional responses of phytoplankton functional groups were assayed. Responses of the diatom, haptophyte, and dinoflagellate functional groups in simulated blooms were unique, with diatoms and haptophytes significantly (95% confidence) shifting their quantitative metabolic fingerprint from the in situ condition, whereas dinoflagellates showed little response. Significantly differentially abundant genes identified the importance of colimitation by nutrients, metals, and vitamins in eukaryotic phytoplankton metabolism and bloom formation in this system. The variable transcript allocation ratio, used to quantify transcript reallocation following DSW amendment, differed for diatoms and haptophytes, reflecting the long-standing paradigm of phytoplankton r- and K-type growth strategies. Although the underlying metabolic potential of the large eukaryotic phytoplankton was consistently present, the lack of a bloom during the study period suggests a crucial dependence on physical and biogeochemical forcing, which are susceptible to alteration with changing climate.

  8. Surface modification influencing adsorption of red wine constituents: The role of functional groups

    NASA Astrophysics Data System (ADS)

    Mierczynska-Vasilev, Agnieszka; Smith, Paul A.

    2016-11-01

    The adsorption of wine constituents at solid surfaces is important in applications such as filtration and membrane fouling, binding to tanks and fittings and interactions with processing aids such as bentonite. The interaction of wine constituents with surfaces is mediated through adsorbed wine components, where the type of constituents, amount, orientation, and conformation are of consequence for the surface response. This study examines the effect of surface chemical functionalities on the adsorption of red wine constituents. Plasma-polymerized films rich in amine, carboxyl, hydroxyl, formyl and methyl functional groups were generated on solid substrates whereas, glycidyltrimethylammonium chloride was covalently attached to allylamine plasma-polymer modified surface and poly(sodium styrenesulfonate) was electrostatically adsorbed to an amine plasma-polymerized surface. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy. The ability of different substrates to adsorb red wine constituents was evaluated by quartz crystal microbalance and atomic force microscopy. The results showed that substrates modified with -SO3H and -COOH groups can adsorb more of the wine nitrogen-containing compounds whereas -NH2 and -NR3 groups encourage carbon-containing compounds adsorption. Red wine constituents after filtration were adsorbed in higher extend on -NR3 and -CHO surfaces. The -OH modified surfaces had the lowest ability to absorb wine components.

  9. Functional group-specific traits drive phytoplankton dynamics in the oligotrophic ocean

    PubMed Central

    Alexander, Harriet; Rouco, Mónica; Haley, Sheean T.; Wilson, Samuel T.; Karl, David M.; Dyhrman, Sonya T.

    2015-01-01

    A diverse microbial assemblage in the ocean is responsible for nearly half of global primary production. It has been hypothesized and experimentally demonstrated that nutrient loading can stimulate blooms of large eukaryotic phytoplankton in oligotrophic systems. Although central to balancing biogeochemical models, knowledge of the metabolic traits that govern the dynamics of these bloom-forming phytoplankton is limited. We used eukaryotic metatranscriptomic techniques to identify the metabolic basis of functional group-specific traits that may drive the shift between net heterotrophy and autotrophy in the oligotrophic ocean. Replicated blooms were simulated by deep seawater (DSW) addition to mimic nutrient loading in the North Pacific Subtropical Gyre, and the transcriptional responses of phytoplankton functional groups were assayed. Responses of the diatom, haptophyte, and dinoflagellate functional groups in simulated blooms were unique, with diatoms and haptophytes significantly (95% confidence) shifting their quantitative metabolic fingerprint from the in situ condition, whereas dinoflagellates showed little response. Significantly differentially abundant genes identified the importance of colimitation by nutrients, metals, and vitamins in eukaryotic phytoplankton metabolism and bloom formation in this system. The variable transcript allocation ratio, used to quantify transcript reallocation following DSW amendment, differed for diatoms and haptophytes, reflecting the long-standing paradigm of phytoplankton r- and K-type growth strategies. Although the underlying metabolic potential of the large eukaryotic phytoplankton was consistently present, the lack of a bloom during the study period suggests a crucial dependence on physical and biogeochemical forcing, which are susceptible to alteration with changing climate. PMID:26460011

  10. Chemical functionalization of nanodiamond by amino groups: an X-ray photoelectron spectroscopy study.

    PubMed

    Dhanak, V R; Butenko, Yu V; Brieva, A C; Coxon, P R; Alves, L; Siller, L

    2012-04-01

    The development of chemical functionalization techniques for diamond nanocrystallites opens up ways with a view to altering their solubility in different solvents, improve interfacial adhesion of nanodiamonds with a composite matrix in new materials, and provide new possibilities for the modification of the electronic properties of nanodiamond crystallites. In this work, we present results on the chemical functionalization of nanodiamonds by amino groups using ammonia as a nitrogenation agent. Nanodiamond material used was formed by the detonation technique with average crystallite sizes of 4-5 nm. The final materials and intermediates products were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Chemical functionalization of nanodiamonds by amino groups could enable the preparation of new nylon nano-composite materials. Presence of surface amino groups could alter pH of nanodiamond colloids towards basic values and improve colloidal stability of nanodiamond suspensions at pH close to 7. This could enable syntheses of new drug delivery systems based on nanodiamonds.

  11. A guide to the selection of switchable functional groups for CO2-switchable compounds.

    PubMed

    Alshamrani, A K; Vanderveen, J R; Jessop, P G

    2016-07-28

    Many CO2-responsive species, including many of the CO2-switchable surfactants, solvents, solutes, gels, colloids, and surfaces, rely on the ability of CO2 to lower the pH of water. Uncharged basic groups on the CO2-responsive species are therefore converted from a neutral state to a protonated cationic state (a bicarbonate salt), which causes dramatic and useful changes to the properties of the species. However, this switching process only works correctly if a basic group of appropriate basicity has been selected. This article presents a comprehensive guide to the selection of basic groups for CO2-switchable species for use in water. The appropriate basicity, as measured by the pKaH (the pKa of the protonated compound), is a function of the concentration of the switchable species, the temperature, the pressure of CO2, the presence or absence of an organic liquid phase, and the solubility of the neutral form of the compound.

  12. Magneto-Sensitive Adsorbents Modified by Functional Nitrogen-Containing Groups

    NASA Astrophysics Data System (ADS)

    Melnyk, Inna V.; Gdula, Karolina; Dąbrowski, Andrzej; Zub, Yuriy L.

    2016-02-01

    In order to obtain amino-functionalized silica materials with magnetic core, one-step synthesis was carried out. Several materials, differ in number and structure of amino groups, were synthesized on the basis of sol-gel method. The synthesized materials were examined by several analytical techniques. The presence and content of amino groups were measured by using Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and acid-base titration, respectively. Specific surface areas were measured by nitrogen/adsorption desorption isotherms. It was proved that sol-gel approach leads to obtain materials with high content of amino groups built into their surfaces (in the range 1.6-2.7 mmol/g). As-obtained materials were tested as potential adsorbents for copper(II) ions. The received maximum adsorption capacities were in the range 0.4-0.7 mmol/g.

  13. Identifying functional groups for response to disturbance in an abandoned pasture

    NASA Astrophysics Data System (ADS)

    Lavorel, Sandra; Touzard, Blaise; Lebreton, Jean-Dominique; Clément, Bernard

    1998-06-01

    In an abandoned pasture in Brittany, we compared artificial small-scale disturbances to natural disturbances by wild boar and undisturbed vegetation. We developed a multivariate statistical approach which analyses how species biological attributes explain the response of community composition to disturbances. This technique, which reconciles the inductive and deductive approaches for functional classifications, identifies groups of species with similar responses to disturbance and characterizes their biological profiles. After 5 months of recolonization, artificial disturbances had a greater species richness than undisturbed vegetation as a result of recruitment of new species without the exclusion of pre-existing matrix species. Species morphology, described by canopy structure, canopy height and lateral spread, explained a large part (16 %) of community response to disturbance. Regeneration strategies, described by life history, seed mass, dispersal agent, dormancy and the existence of vegetative multiplication, explained a smaller part of community response to disturbance (8 %). Artificial disturbances were characterized by therophyte and compact rosettes with moderately dormant seeds, including a number of Asteraceae and other early successional species. Natural disturbances were colonized by leafy guerrilla species without seed dormancy. Few species were tightly related to undisturbed vegetation and were essentially grasses with a phalanx rosette morphology. The functional classification obtained is consistent with the classification of the community into fugitives, regenerators and persistors. These groups are structured according to Grubb's model for temperate grasslands, with regenerators and persistors in the matrix and fugitives taking advantage of gaps open by small-scale disturbances. The conjunction of functional diversity and species diversity within functional groups is the key to resilience to disturbance, an important ecosystem function.

  14. The two-point correlation function for groups of galaxies in the Center for Astrophysics redshift survey

    NASA Technical Reports Server (NTRS)

    Ramella, Massimo; Geller, Margaret J.; Huchra, John P.

    1990-01-01

    The large-scale distribution of groups of galaxies selected from complete slices of the CfA redshift survey extension is examined. The survey is used to reexamine the contribution of group members to the galaxy correlation function. The relationship between the correlation function for groups and those calculated for rich clusters is discussed, and the results for groups are examined as an extension of the relation between correlation function amplitude and richness. The group correlation function indicates that groups and individual galaxies are equivalent tracers of the large-scale matter distribution. The distribution of group centers is equivalent to random sampling of the galaxy distribution. The amplitude of the correlation function for groups is consistent with an extrapolation of the amplitude-richness relation for clusters. The amplitude scaled by the mean intersystem separation is also consistent with results for richer clusters.

  15. Synthesis and characterization of bifunctional surfaces with tunable functional group pairs

    NASA Astrophysics Data System (ADS)

    Galloway, John M.; Kung, Mayfair; Kung, Harold H.

    2016-06-01

    Grafting of pairs of functional groups onto a silica surface was demonstrated by tethering both terminals of an organochlorosilane precursor molecule, Cl2(CH3)Si(CH2)4(CO)(OSi(i-Pr)2)(CH2)2Si(CH3)Cl2, that possess a cleavable silyl ester bond, onto a silica surface. Hydrolytic cleavage of the silyl ester bond of the grafted molecule resulted in the generation of organized pairs of carboxylic acid and organosilanol groups. This organosilanol moiety was easily transformed into other functional groups through condensation reactions to form, together with the neighboring acid group, pairs such as carboxylic acid/secondary amine, carboxylic acid/pyridine, and carboxylic acid/phosphine. In the case of carboxylic acid/amine pairing, there was evidence of the formation of amide. A sample grafted with amine-carboxylic acid pairs was three times more active (per free amine) than a sample without such pairs for the nitroaldol condensation of 4-nitrobenzaldehyde and nitromethane.

  16. Coumestan inhibits radical-induced oxidation of DNA: is hydroxyl a necessary functional group?

    PubMed

    Xi, Gao-Lei; Liu, Zai-Qun

    2014-06-18

    Coumestan is a natural tetracycle with a C═C bond shared by a coumarin moiety and a benzofuran moiety. In addition to the function of the hydroxyl group on the antioxidant activity of coumestan, it is worth exploring the influence of the oxygen-abundant scaffold on the antioxidant activity as well. In this work, seven coumestans containing electron-withdrawing and electron-donating groups were synthesized to evaluate the abilities to trap 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(•+)), 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), and galvinoxyl radical, respectively, and to inhibit the oxidations of DNA mediated by (•)OH, Cu(2+)/glutathione (GSH), and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), respectively. It was found that all of the coumestans used herein can quench the aforementioned radicals and can inhibit (•)OH-, Cu(2+)/GSH-, and AAPH-induced oxidations of DNA. In particular, substituent-free coumestan exhibits higher ability to quench DPPH and to inhibit AAPH-induced oxidation of DNA than Trolox. In addition, nonsubstituted coumestan shows a similar ability to inhibit (•)OH- and Cu(2+)/GSH-induced oxidations of DNA relative to that of Trolox. The antioxidant effectiveness of the coumestan can be attributed to the lactone in the coumarin moiety and, therefore, a hydroxyl group may not be a necessary functional group for coumestan to be an antioxidant.

  17. Molecular weight distribution and functional group profiles of TEMPO-oxidized lyocell fibers.

    PubMed

    Milanovic, Jovana; Schiehser, Sonja; Milanovic, Predrag; Potthast, Antje; Kostic, Mirjana

    2013-10-15

    The effects of TEMPO-mediated oxidation, performed with NaClO, a catalytic amount of NaBr, and 2,2',6,6'-tetramethylpiperidine-1-oxy radical (TEMPO), were studied on lyocell fibers by means of GPC using multiple detection and group-selective fluorescence labeling according to the CCOA and FDAM methodology. The applied method determines functional group content as a sum parameter, as well as functional group profiles in relation to the molecular weight of the cellulose fibers. Both the CHO and COOH profiles, as well as molecular weight alterations, were analyzed. A significant decrease in the average molecular weight was obtained during the first hour of TEMPO-mediated oxidation, but prolonged oxidation time resulted in no strong additional chain scission. Significant amounts of COOH groups were introduced in the high molecular weight fractions by the oxidation with higher concentrations of NaClO (2.42-9.67 mmol NaClO/g fiber) after modification times of 1h or longer.

  18. Gas-phase reactivity of carboxylic acid functional groups with carbodiimides.

    PubMed

    Prentice, Boone M; Gilbert, Joshua D; Stutzman, John R; Forrest, William P; McLuckey, Scott A

    2013-01-01

    Gas-phase modification of carboxylic acid functionalities is performed via ion/ion reactions with carbodiimide reagents [N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide (CMC) and [3-(3-Ethylcarbodiimide-1-yl)propyl]trimethylaminium (ECPT)]. Gas-phase ion/ion covalent chemistry requires the formation of a long-lived complex. In this instance, the complex is stabilized by an electrostatic interaction between the fixed charge quaternary ammonium group of the carbodiimide reagent cation and the analyte dianion. Subsequent activation results in characteristic loss of an isocyanate derivative from one side of the carbodiimide functionality, a signature for this covalent chemistry. The resulting amide bond is formed on the analyte at the site of the original carboxylic acid. Reactions involving analytes that do not contain available carboxylic acid groups (e.g., they have been converted to sodium salts) or reagents that do not have the carbodiimide functionality do not undergo a covalent reaction. This chemistry is demonstrated using PAMAM generation 0.5 dendrimer, ethylenediaminetetraacetic acid (EDTA), and the model peptide DGAILDGAILD. This work demonstrates the selective gas-phase covalent modification of carboxylic acid functionalities.

  19. Functionalization of metal-organic frameworks through the postsynthetic transformation of olefin side groups.

    PubMed

    Hindelang, Konrad; Kronast, Alexander; Vagin, Sergei I; Rieger, Bernhard

    2013-06-17

    For the first time, the adaptability of the C=C double bond as a versatile precursor for the postsynthetic modification (PSM) of microporous materials was extensively investigated and evaluated. Therefore, an olefin-tagged 4,4'-bipyridine linker was synthesized and successfully introduced as pillar linker within a 9,10-triptycenedicarboxylate (TDC) zinc paddle-wheel metal-organic framework (MOF) through microwave-assisted synthesis. Different reactions, predominately used in organic chemistry, were tested, leading to the development of new postsynthetic reactions for the functionalization of solid materials. The postsynthetic oxidation of the olefin side groups applying osmium tetroxide (OsO₄) as a catalyst led to the formation of a microporous material with free vicinal diol functionalities. The epoxidation with dimethyldioxirane (DMDO) enabled the synthesis of epoxy-functionalized MOFs. In addition to that, reaction procedures for a postsynthetic hydroboration with borane dimethyl sulfide as well as a photoinduced thiol-ene click reaction with ethyl mercaptan were developed. For all of these PSMs, yields of more than 90% were obtained, entirely maintaining the crystallinity of the MOFs. Since the direct introduction of the corresponding groups by means of pre-synthetic approaches is hardly possible, these new PSMs are useful tools for the functionalization of porous solids towards applications such as selective adsorption, separation, and catalysis.

  20. Evidence supporting the importance of microbial functional groups in decomposition models

    NASA Astrophysics Data System (ADS)

    Todd-Brown, K. E.; Lu, L.; Allison, S. D.

    2010-12-01

    Microbial communities mediate organic carbon decomposition in both soil and marine environments. Decomposition depends on microbes that produce extracellular enzymes to degrade complex organic matter, as well as microbes that mineralize simple organic matter to CO2. Therefore microbes could be represented in Earth system models as functional groups based on the extracellular enzymes they produce. However, the importance of including the functional diversity of microbes in decomposition models has been unclear. In this study we simulated microbial functional diversity with two strains of Pseudomonas fluorescens bacteria, one of which secretes extracellular protease and one that does not. These two strains were competed on several carbon resources including casein-glucose, casamino acids-glucose and glucose over several days. We then fit a series of models to the resulting data: 1) an explicit model representing both biomass and substrate pools, 2) a simplified substrate pool model with two biomass pools and one substrate pool, 3) a simplified biomass pool model with one biomass and two substrate pools, 4) a simplified biomass/substrate pool model with one biomass and one substrate pool, and 5) a single carbon pool model. We found that the explicit model (#1) fit the laboratory data significantly better than the other models, suggesting that functional groups and substrate pools should be represented in global decomposition models with time steps on the order of hours.

  1. A meta‐analysis of functional group responses to forest recovery outside of the tropics

    PubMed Central

    Ezard, Thomas H. G.; Martin, Philip A.; Newton, Adrian C.; Doncaster, C. Patrick

    2015-01-01

    Abstract Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old‐growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta‐analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old‐growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional‐group–specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old‐growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old‐growth values (between 140 years and never for recovery to old‐growth values at 95% prediction limits). Non‐saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old‐growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives. PMID:26040756

  2. Various fates of neuronal progenitor cells observed on several different chemical functional groups

    NASA Astrophysics Data System (ADS)

    Liu, Xi; Wang, Ying; He, Jin; Wang, Xiu-Mei; Cui, Fu-Zhai; Xu, Quan-Yuan

    2011-12-01

    Neuronal progenitor cells cultured on gold-coated glass surfaces modified by different chemical functional groups, including hydroxyl (-OH), carboxyl (-COOH), amino (-NH2), bromo (-Br), mercapto (-SH), - Phenyl and methyl (-CH3), were studied here to investigate the influence of surface chemistry on the cells' adhesion, morphology, proliferation and functional gene expression. Focal adhesion staining indicated in the initial culture stage cells exhibited morphological changes in response to different chemical functional groups. Cells cultured on -NH2 grafted surface displayed focal adhesion plaque and flattened morphology and had the largest contact area. However, their counter parts on -CH3 grafted surface displayed no focal adhesion and rounded morphology and had the smallest contact area. After 6 days culture, the proliferation trend was as follows: -NH2 > -SH> -COOH> - Phenyl > - Br > -OH> -CH3. To determine the neural functional properties of the cells affected by surface chemistry, the expression of glutamate decarboxylase (GAD67), nerve growth factor (NGF) and brainderived neurotrophic factor (BDNF) were characterized. An increase of GAD67 expression was observed on -NH2, -COOH and -SH grafted surfaces, while no increase in NGF and BDNF expression was observed on any chemical surfaces. These results highlight the importance of surface chemistry in the fate determination of neuronal progenitor cells, and suggest that surface chemistry must be considered in the design of biomaterials for neural tissue engineering.

  3. Fossil group origins. V. The dependence of the luminosity function on the magnitude gap

    NASA Astrophysics Data System (ADS)

    Zarattini, S.; Aguerri, J. A. L.; Sánchez-Janssen, R.; Barrena, R.; Boschin, W.; del Burgo, C.; Castro-Rodriguez, N.; Corsini, E. M.; D'Onghia, E.; Girardi, M.; Iglesias-Páramo, J.; Kundert, A.; Méndez-Abreu, J.; Vilchez, J. M.

    2015-09-01

    Context. In nature we observe galaxy aggregations that span a wide range of magnitude gaps between the two first-ranked galaxies of a system (Δm12). Thus, there are systems with gaps close to zero (e.g., the Coma cluster), and at the other extreme of the distribution, the largest gaps are found among the so-called fossil systems. The observed distribution of magnitude gaps is thought to be a consequence of the orbital decay of M∗ galaxies in massive halos and the associated growth of the central object. As a result, to first order the amplitude of this gap is a good statistical proxy for the dynamical age of a system of galaxies. Fossil and non-fossil systems could therefore have different galaxy populations that should be reflected in their luminosity functions. Aims: In this work we study, for the first time, the dependence of the luminosity function parameters on Δm12 using data obtained by the fossil group origins (FOGO) project. Methods: We constructed a hybrid luminosity function for 102 groups and clusters at z ≤ 0.25 using both photometric data from the SDSS-DR7 and redshifts from the DR7 and the FOGO surveys. The latter consists of ~1200 new redshifts in 34 fossil system candidates. We stacked all the individual luminosity functions, dividing them into bins of Δm12, and studied their best-fit Schechter parameters. We additionally computed a "relative" luminosity function, expressed as a function of the central galaxy luminosity, which boosts our capacity to detect differences - especially at the bright end. Results: We find trends as a function of Δm12 at both the bright and faint ends of the luminosity function. In particular, at the bright end, the larger the magnitude gap, the fainter the characteristic magnitude M∗. The characteristic luminosity in systems with negligible gaps is more than a factor three brighter than in fossil-like ones. Remarkably, we also find differences at the faint end. In this region, the larger the gap, the flatter

  4. Spectral functions with the density matrix renormalization group: Krylov-space approach for correction vectors

    NASA Astrophysics Data System (ADS)

    Nocera, A.; Alvarez, G.

    2016-11-01

    Frequency-dependent correlations, such as the spectral function and the dynamical structure factor, help illustrate condensed matter experiments. Within the density matrix renormalization group (DMRG) framework, an accurate method for calculating spectral functions directly in frequency is the correction-vector method. The correction vector can be computed by solving a linear equation or by minimizing a functional. This paper proposes an alternative to calculate the correction vector: to use the Krylov-space approach. This paper then studies the accuracy and performance of the Krylov-space approach, when applied to the Heisenberg, the t-J, and the Hubbard models. The cases studied indicate that the Krylov-space approach can be more accurate and efficient than the conjugate gradient, and that the error of the former integrates best when a Krylov-space decomposition is also used for ground state DMRG.

  5. Sequential Linker Installation: Precise Placement of Functional Groups in Multivariate Metal-Organic Frameworks

    SciTech Connect

    Yuan, S; Lu, WG; Chen, YP; Zhang, Q; Liu, TF; Feng, DW; Wang, X; Qin, JS; Zhou, HC

    2015-03-11

    A unique strategy, sequential linker installation (SLI), has been developed to construct multivariate MOFs with functional groups precisely positioned. PCN-700, a Zr-MOF with eight-connected Zr6O4(OH)(8)(H2O)(4) clusters, has been judiciously designed; the Zr-6 clusters in this MOF are arranged in such a fashion that, by replacement of terminal OH-/H2O ligands, subsequent insertion of linear dicarboxylate linkers is achieved. We demonstrate that linkers with distinct lengths and functionalities can be sequentially installed into PCN-700. Single-crystal to single-crystal transformation is realized so that the positions of the subsequently installed linkers are pinpointed via single-crystal X-ray diffraction analyses. This methodology provides a powerful tool to construct multivariate MOFs with precisely positioned functionalities in the desired proximity, which would otherwise be difficult to achieve.

  6. Cloning and heterologous expression of two aryl-aldehyde dehydrogenases from the white-rot basidiomycete Phanerochaete chrysosporium

    SciTech Connect

    Nakamura, Tomofumi; Ichinose, Hirofumi; Wariishi, Hiroyuki

    2010-04-09

    We identified two aryl-aldehyde dehydrogenase proteins (PcALDH1 and PcALDH2) from the white-rot basidiomycete Phanerochaete chrysosporium. Both PcALDHs were translationally up-regulated in response to exogenous addition of vanillin, one of the key aromatic compounds in the pathway of lignin degradation by basidiomycetes. To clarify the catalytic functions of PcALDHs, we isolated full-length cDNAs encoding these proteins and heterologously expressed the recombinant enzymes using a pET/Escherichia coli system. The open reading frames of both PcALDH1 and PcALDH2 consisted of 1503 nucleotides. The deduced amino acid sequences of both proteins showed high homologies with aryl-aldehyde dehydrogenases from other organisms and contained ten conserved domains of ALDHs. Moreover, a novel glycine-rich motif 'GxGxxxG' was located at the NAD{sup +}-binding site. The recombinant PcALDHs catalyzed dehydrogenation reactions of several aryl-aldehyde compounds, including vanillin, to their corresponding aromatic acids. These results strongly suggested that PcALDHs metabolize aryl-aldehyde compounds generated during fungal degradation of lignin and various aromatic xenobiotics.

  7. Molecularly Imprinted Sol-Gel-Based QCM Sensor Arrays for the Detection and Recognition of Volatile Aldehydes.

    PubMed

    Liu, Chuanjun; Wyszynski, Bartosz; Yatabe, Rui; Hayashi, Kenshi; Toko, Kiyoshi

    2017-02-16

    The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM) sensor arrays based on molecularly imprinted sol-gel (MISG) materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL); nonanal (NAL) and bezaldehyde (BAL). The MISGs were prepared by a sol-gel procedure using two matrix precursors: tetraethyl orthosilicate (TEOS) and tetrabutoxytitanium (TBOT). Aminopropyltriethoxysilane (APT); diethylaminopropyltrimethoxysilane (EAP) and trimethoxy-phenylsilane (TMP) were added as functional monomers to adjust the imprinting effect of the matrix. Hexanoic acid (HA); nonanoic acid (NA) and benzoic acid (BA) were used as psuedotemplates in view of their analogous structure to the target molecules as well as the strong hydrogen-bonding interaction with the matrix. Totally 13 types of MISGs with different components were prepared and coated on QCM electrodes by spin coating. Their sensing characters towards the three aldehyde vapors with different concentrations were investigated qualitatively. The results demonstrated that the response of individual sensors to each target strongly depended on the matrix precursors; functional monomers and template molecules. An optimization of the 13 MISG materials was carried out based on statistical analysis such as principle component analysis (PCA); multivariate analysis of covariance (MANCOVA) and hierarchical cluster analysis (HCA). The optimized sensor array consisting of five channels showed a high discrimination ability on the aldehyde vapors; which was confirmed by quantitative comparison with a randomly selected array. It was suggested that both the molecularly imprinting (MIP) effect and the matrix

  8. Molecularly Imprinted Sol-Gel-Based QCM Sensor Arrays for the Detection and Recognition of Volatile Aldehydes

    PubMed Central

    Liu, Chuanjun; Wyszynski, Bartosz; Yatabe, Rui; Hayashi, Kenshi; Toko, Kiyoshi

    2017-01-01

    The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM) sensor arrays based on molecularly imprinted sol-gel (MISG) materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL); nonanal (NAL) and bezaldehyde (BAL). The MISGs were prepared by a sol-gel procedure using two matrix precursors: tetraethyl orthosilicate (TEOS) and tetrabutoxytitanium (TBOT). Aminopropyltriethoxysilane (APT); diethylaminopropyltrimethoxysilane (EAP) and trimethoxy-phenylsilane (TMP) were added as functional monomers to adjust the imprinting effect of the matrix. Hexanoic acid (HA); nonanoic acid (NA) and benzoic acid (BA) were used as psuedotemplates in view of their analogous structure to the target molecules as well as the strong hydrogen-bonding interaction with the matrix. Totally 13 types of MISGs with different components were prepared and coated on QCM electrodes by spin coating. Their sensing characters towards the three aldehyde vapors with different concentrations were investigated qualitatively. The results demonstrated that the response of individual sensors to each target strongly depended on the matrix precursors; functional monomers and template molecules. An optimization of the 13 MISG materials was carried out based on statistical analysis such as principle component analysis (PCA); multivariate analysis of covariance (MANCOVA) and hierarchical cluster analysis (HCA). The optimized sensor array consisting of five channels showed a high discrimination ability on the aldehyde vapors; which was confirmed by quantitative comparison with a randomly selected array. It was suggested that both the molecularly imprinting (MIP) effect and the matrix

  9. Aldehyde dehydrogenase 3 converts farnesal into farnesoic acid in the corpora allata of mosquitoes.

    PubMed

    Rivera-Perez, Crisalejandra; Nouzova, Marcela; Clifton, Mark E; Garcia, Elena Martin; LeBlanc, Elizabeth; Noriega, Fernando G

    2013-08-01

    The juvenile hormones (JHs) play a central role in insect reproduction, development and behavior. Interrupting JH biosynthesis has long been considered a promising strategy for the development of target-specific insecticides. Using a combination of RNAi, in vivo and in vitro studies we characterized the last unknown biosynthetic enzyme of the JH pathway, a fatty aldehyde dehydrogenase (AaALDH3) that oxidizes farnesal into farnesoic acid (FA) in the corpora allata (CA) of mosquitoes. The AaALDH3 is structurally and functionally a NAD(+)-dependent class 3 ALDH showing tissue- and developmental-stage-specific splice variants. Members of the ALDH3 family play critical roles in the development of cancer and Sjögren-Larsson syndrome in humans, but have not been studies in groups other than mammals. Using a newly developed assay utilizing fluorescent tags, we demonstrated that AaALDH3 activity, as well as the concentrations of farnesol, farnesal and FA were different in CA of sugar and blood-fed females. In CA of blood-fed females the low catalytic activity of AaALDH3 limited the flux of precursors and caused a remarkable increase in the pool of farnesal with a decrease in FA and JH synthesis. The accumulation of the potentially toxic farnesal stimulated the activity of a reductase that converted farnesal back into farnesol, resulting in farnesol leaking out of the CA. Our studies indicated AaALDH3 plays a key role in the regulation of JH synthesis in blood-fed females and mosquitoes seem to have developed a "trade-off" system to balance the key role of farnesal as a JH precursor with its potential toxicity.

  10. Protocatechuic aldehyde ameliorates experimental pulmonary fibrosis by modulating HMGB1/RAGE pathway

    SciTech Connect

    Zhang, Liang Ji, Yunxia Kang, Zechun Lv, Changjun Jiang, Wanglin

    2015-02-15

    An abnormal high mobility group box 1 (HMGB1) activation and a decrease in receptor for advanced glycation end-product (RAGE) play a key role in the pathogenesis of pulmonary fibrosis. Protocatechuic aldehyde (PA) is a naturally occurring compound, which is extracted from the degradation of phenolic acids. However, whether PA has anti-fibrotic functions is unknown. In this study, the effects of PA on the transforming growth factor-β1 (TGF-β1)-mediated epithelial–mesenchymal transition (EMT) in A549 cells, on the apoptosis of human type I alveolar epithelial cells (AT I), on the proliferation of human lung fibroblasts (HLF-1) in vitro, and on bleomycin (BLM)-induced pulmonary fibrosis in vivo were investigated. PA treatment resulted in a reduction of EMT in A549 cells with a decrease in vimentin and HMGB, an increase of E-cadherin and RAGE, a reduction of HLF-1 proliferation with a decrease of fibroblast growth factor 2 (FGF-2) and platelet-derived growth factor (PDGF). Apoptosis of AT I was attenuated with an increase of RAGE. PA ameliorated BLM-induced pulmonary fibrosis in rats with a reduction of histopathological scores and collagen deposition, and a lower FGF-2, PDGF, α-smooth muscle actin (α-SMA) and HMGB1 expression, whereas higher RAGE was found in BLM-instilled lungs. Through the decrease of HGMB1 and the regulation of RAGE, PA reversed the EMT, inhibited HLF-1 proliferation as well as reduced apoptosis in AT I, and prevented pulmonary fibrosis in vivo. Collectively, our results demonstrate that PA prevents experimental pulmonary fibrosis by modulating HMGB1/RAGE pathway. - Highlights: • PA prevents EMT, reduces the apoptosis of AT1 in vitro. • PA decreases proliferation of HLF-1, reduces PDGF and FGF expression in vitro. • PA prevents experimental pulmonary fibrosis by modulating the HMGB1/RAGE pathway.

  11. Function of the triceps surae muscle group in low and high arched feet: an exploratory study.

    PubMed

    Branthwaite, Helen; Pandyan, Anand; Chockalingam, Nachiappan

    2012-06-01

    The Achilles tendon has been shown to be comprised of segmental components of tendon arising from the tricpes surae muscle group. Motion of the foot joints in low and high arched feet may induce a change in behaviour of the triceps surae muscle group due to altered strain on the tendon. Surface electromyogram of the medial and lateral gastrocnemius and the soleus muscle from 12 subjects (with 6 low arched and 6 high arched feet) (1:1) was recorded whilst walking at a self selected speed along a 10m walkway. The results showed a high variability in muscle activity between groups with patterns emerging within groups. Soleus was more active in 50% of the low arch feet at forefoot loading and there was a crescendo of activity towards heel lift in 58% of all subjects. This observed variability between groups and foot types emphasises the need for further work on individual anatomical variation and foot function to help in the understanding and management of Achilles tendon pathologies and triceps surae dysfunction.

  12. Triggering the approach of an arene or heteroarene towards an aldehyde via Lewis acid-aldehyde communication.

    PubMed

    Pratihar, Sanjay

    2016-03-14

    The present work reports a combined experimental/computational study of the Lewis acid promoted hydroxyalkylation reaction involving aldehyde and arene/heteroarene and reveals a mechanism in which the rate determining aldehyde to alcohol formation via a four-member cyclic transition state (TS) involves a transfer of hydrogen from arene/heteroarene C-H to aldehyde oxygen with the breaking of the C-H bond and formation of C-C and O-H bonds. The effect of different Sn(iv) derivatives on the hydroxyalkylation reaction from different in situ NMR and computational studies reveals that although the exergonic formation of the intermediate and its gained electrophilicity at the carbonyl carbon drive the reaction in SnCl4 compared to other Sn(iv) derivatives, the overall reaction is low yielding because of its stable intermediate. With respect to different aldehydes, LA promoted hydroxylation was found to be more feasible for an electron withdrawing aldehyde compared to electron rich aldehyde because of lower stability, enhanced electrophilicity gained at the aldehyde center, and a lower activation barrier between its intermediate and TS in the former as compared to the latter. The relative stability of the LA-aldehyde adduct decreases in the order SnCl4 > AlCl3 > InCl3 > BF3 > ZnCl2 > TiCl4 > SiCl4, while the activation barrier (ΔG(#)) between intermediate and transition states increases in the order AlCl3 < SnCl4 < InCl3 < BF3 < TiCl4 < ZnCl2 < SiCl4. On the other hand, the activation barriers in the case of different arenes/heteroarenes are in the order of indole < furan < anisole < thiophene < toluene < benzene < chlorobenzene < cyanobenzene, which suggests a facile reaction in the case of indole and the most difficult reaction in the case of cyanobenzene. The ease of formation of the corresponding diaryl methyl carbocation from the alcohol-LA intermediate is responsible for the determination of the undesired product and is found to be more viable in the case of strong

  13. Functionalized quantum dots induce proinflammatory responses in vitro: the role of terminal functional group-associated endocytic pathways

    NASA Astrophysics Data System (ADS)

    Zhang, Yijuan; Pan, Hong; Zhang, Pengfei; Gao, Ningning; Lin, Yi; Luo, Zichao; Li, Ping; Wang, Ce; Liu, Lanlan; Pang, Daiwen; Cai, Lintao; Ma, Yifan

    2013-06-01

    PEGylation has been applied as an effective strategy of surface functionalization to improve the stability and reduce non-specific binding of quantum dots (QDs). However, its effects on the proinflammatory properties of QDs and the underlying mechanism have not been well elucidated yet. Herein, the proinflammatory effects of PEGylated CdSe/ZnS QDs with an amphiphilic polymer coating (PEG-pQDs) were investigated in human pulmonary epithelial cells and macrophages by evaluating the cytokine/chemokine production. The results showed that the proinflammatory effects of PEG-pQDs were strongly associated with the functional groups (-COOH, -NH2, -OH, and -OCH3) at the end of PEG chain. COOH-PEG-pQDs demonstrated the most proinflammatory effects followed by NH2-PEG-pQDs and HO-PEG-pQDs with CH3O-PEG-pQDs exhibiting the least proinflammatory effects. The proinflammatory effects of PEG-pQDs relied on lipid raft- and class A scavenger receptor (SRA)-dependent endocytic pathways as well as the downstream NF-κB and MAPK signaling cascades. COOH-PEG-pQDs were selectively internalized by lipid raft- and SRA-mediated endocytosis, which consequently activated NF-κB signaling pathway. On the other hand, NH2-PEG-pQDs and HO-PEG-pQDs were mostly internalized via lipid raft-mediated endocytosis, thereby activating p38 MAPK/AP-1 signaling cascades. These data revealed a critical role of terminal functional group-associated endocytic pathways in the proinflammatory responses induced by PEGylated QDs in human pulmonary epithelial cells and macrophages.PEGylation has been applied as an effective strategy of surface functionalization to improve the stability and reduce non-specific binding of quantum dots (QDs). However, its effects on the proinflammatory properties of QDs and the underlying mechanism have not been well elucidated yet. Herein, the proinflammatory effects of PEGylated CdSe/ZnS QDs with an amphiphilic polymer coating (PEG-pQDs) were investigated in human pulmonary epithelial

  14. Competition patterns among phytoplankton functional groups: How useful are the complex mathematical models?

    NASA Astrophysics Data System (ADS)

    Zhao, Jingyang; Ramin, Maryam; Cheng, Vincent; Arhonditsis, George B.

    2008-05-01

    Simple models have significant contribution to the development of ecological theory. However, these minimalistic modeling approaches usually focus on a small subset of the causes of a phenomenon and neglect important aspects of system dynamics. In this study, we use a complex aquatic biogeochemical model to examine competition patterns and structural shifts in the phytoplankton community under nutrient enrichment conditions. Our model simulates multiple elemental cycles (org. C, N, P, Si, O), multiple functional phytoplankton (diatoms, green algae and cyanobacteria) and zooplankton (copepods and cladocerans) groups. It also takes into account recent advances in stoichiometric nutrient recycling theory, and the zooplankton grazing term is reformulated to include algal food quality effects on zooplankton assimilation efficiency. The model provided a realistic platform to examine the functional properties (e.g., kinetics, growth strategies, intracellular storage capacity) and the abiotic conditions (temperature, nutrient loading) under which the different phytoplankton groups can dominate or can be competitively excluded in oligo, meso and eutrophic environments. Based on the results of our analysis, the intergroup variability in the minimum cell quota and maximum transport rate at the cell surface for phosphorus along with the group-specific metabolic losses can shape the structure of plankton communities. We also use classification tree analysis to elucidate aspects (e.g., relative differences in the functional group properties, critical values of the abiotic conditions, levels of the other plankton community residents) of the complex interplay among physical, chemical and biological factors that drive epilimnetic plankton dynamics. Finally, our study highlights the importance of improving the mathematical representation of phytoplankton adaptive strategies for resources procurement (e.g., regulation of transport kinetics, effects of transport kinetics on the

  15. Water Desalination through Zeolitic Imidazolate Framework Membranes: Significant Role of Functional Groups.

    PubMed

    Gupta, Krishna M; Zhang, Kang; Jiang, Jianwen

    2015-12-08

    A molecular simulation study is reported for water desalination through five zeolitic imidazolate framework (ZIF) membranes, namely ZIF-25, -71, -93, -96, and -97. The five ZIFs possess identical rho-topology but differ in functional groups. The rejection of salt (NaCl) is found to be around 97% in ZIF-25, and 100% in the other four ZIFs. The permeance ranges from 27 to 710 kg/(m(2)·h·bar), about one∼two orders of magnitude higher compared with commercial reverse osmosis membranes. Due to a larger aperture size da, ZIF-25, -71, and -96 exhibit a much higher water flux than ZIF-93 and -97; however, the flux in ZIF-25, -71, and -96 is governed by the polarity of functional group rather than da. With the hydrophobic CH3 group, ZIF-25 has the highest flux despite the smallest da among ZIF-25, -71, and -96. The lifetime of hydrogen bonding in ZIF-25 is shorter than that in ZIF-71 and -96. Furthermore, water molecules undergo a fast flushing motion in ZIF-25, but frequent jumping in ZIF-96 and particularly in ZIF-97. An Arrhenius-type relationship is found between water flux in ZIF-25 and temperature, and the activation energy is predicted to be 6.5 kJ/mol. This simulation study provides a microscopic insight into water desalination in a series of ZIFs, reveals the key factors (aperture size and polarity of functional group) governing water flux, and suggests that ZIF-25 might be an interesting reverse osmosis membrane for high-performance water desalination.

  16. Effects of Plant Diversity, Functional Group Composition, and Fertilization on Soil Microbial Properties in Experimental Grassland

    PubMed Central

    Strecker, Tanja; Barnard, Romain L.; Niklaus, Pascal A.; Scherer-Lorenzen, Michael; Weigelt, Alexandra; Scheu, Stefan; Eisenhauer, Nico

    2015-01-01

    Background Loss of biodiversity and increased nutrient inputs are two of the most crucial anthropogenic factors driving ecosystem change. Although both received considerable attention in previous studies, information on their interactive effects on ecosystem functioning is scarce. In particular, little is known on how soil biota and their functions are affected by combined changes in plant diversity and fertilization. Methodology/Principal Findings We investigated the effects of plant diversity, functional community composition, and fertilization on the biomass and respiration of soil microbial communities in a long-term biodiversity experiment in semi-natural grassland (Jena Experiment). Plant species richness enhanced microbial basal respiration and microbial biomass, but did not significantly affect microbial specific respiration. In contrast, the presence of legumes and fertilization significantly decreased microbial specific respiration, without altering microbial biomass. The effect of legumes was superimposed by fertilization as indicated by a significant interaction between the presence of legumes and fertilization. Further, changes in microbial stoichiometry (C-to-N ratio) and specific respiration suggest the presence of legumes to reduce N limitation of soil microorganisms and to modify microbial C use efficiency. Conclusions/Significance Our study highlights the role of plant species and functional group diversity as well as interactions between plant community composition and fertilizer application for soil microbial functions. Our results suggest soil microbial stoichiometry to be a powerful indicator of microbial functioning under N limited conditions. Although our results support the notion that plant diversity and fertilizer application independently affect microbial functioning, legume effects on microbial N limitation were superimposed by fertilization, indicating significant interactions between the functional composition of plant communities and

  17. Thermodynamic characterization of the biocompatible ionic liquid effects on protein model compounds and their functional groups.

    PubMed

    Attri, Pankaj; Venkatesu, Pannuru

    2011-04-14

    The stability of proteins under co-solvent conditions is dependant on the nature of the co-solvent; the co-solvent can alter a protein's properties and structural effects through bimolecular interactions between its functional groups and co-solvent particles. Ionic liquids (ILs) represent a rather diverse class of co-solvents that are combinations of different ions, which are liquids at or close to room temperature. To quantify the bimolecular interactions of protein functional groups with biocompatible ILs, we report the systematic and quantitative apparent transfer free energies (ΔG'(tr)) of a homologous series of cyclic dipeptides (CDs) from water to aqueous solutions of ILs through solubility measurements, as a function of IL concentration at 25 °C under atmospheric pressure. The materials investigated in the present work included the CDs of cyclo(Gly-Gly), cyclo(Ala-Gly), cyclo(Ala-Ala), cyclo(Leu-Ala), and cyclo(Val-Val). The ILs used such as diethylammonium acetate ([Et(2)NH][CH(3)COO], DEAA), triethylammonium acetate ([Et(3)NH][CH(3)COO], TEAA), diethylammonium dihydogen phosphate ([Et(3)NH][H(2)PO(4)], DEAP), triethylammonium dihydogen phosphate ([Et(3)NH][H(2)PO(4)], TEAP), diethylammonium sulfate ([Et(3)NH][HSO(4)], DEAS) and triethylammonium sulfate ([Et(3)NH][HSO(4)], TEAS). We observed positive values of ΔG'(tr) for CDs from water to ILs, indicating that interactions between ILs and CDs are unfavourable, which leads to stabilization of the native structure of CDs. The experimental results were further used for estimating the transfer free energies (Δg'(tr)) of the peptide bond (-CONH-), the peptide backbone unit (-CH(2)C=ONH-), and various functional groups from water to IL solutions. Our results explicitly elucidate that a series of all ammonium ILs act as stabilizers for tested model compounds through the exclusion of ILs from CDs surface.

  18. Effects of aldehydes on the growth and lipid accumulation of oleaginous yeast Trichosporon fermentans.

    PubMed

    Huang, Chao; Wu, Hong; Liu, Qiu-ping; Li, Yuan-yuan; Zong, Min-hua

    2011-05-11

    The effects of five representative aldehydes in lignocellulosic hydrolysates on the growth and the lipid accumulation of oleaginous yeast Trichosporon fermentans were investigated for the first time. There was no relationship between the hydrophobicity and the toxicity of aldehyde, and 5-hydroxymethylfurfural was less toxic than aromatic aldehydes and furfural. Binary combination of aromatic aldehydes caused a synergistic inhibitory effect, but combination of furan and aromatic aldehydes reduced the inhibition instead. A longer lag phase was found due to the presence of aldehydes and the decrease of sugar consumption rate, but more xylose was utilized by T. fermentans in the presence of aldehydes, especially at their low concentrations. The variation of malic enzyme activity was not related to the delay of lipid accumulation. Furthermore, the inhibition of aldehydes on cell growth was more dependent on inoculum size, temperature, and initial pH than that on lipid content.

  19. A versatile and green mechanochemical route for aldehyde-oxime conversions.

    PubMed

    Aakeröy, Christer B; Sinha, Abhijeet S; Epa, Kanishka N; Spartz, Christine L; Desper, John

    2012-11-28

    A robust, facile and solvent-free mechanochemical path for aldehyde-oxime transformations using hydroxylamine and NaOH is explored; the method is suitable for aromatic and aliphatic aldehydes decorated with a range of substituents.

  20. Applicability of the theory of thermodynamic similarity to predict the enthalpies of vaporization of aliphatic aldehydes

    NASA Astrophysics Data System (ADS)

    Esina, Z. N.; Korchuganova, M. R.

    2015-06-01

    The theory of thermodynamic similarity is used to predict the enthalpies of vaporization of aliphatic aldehydes. The predicted data allow us to calculate the phase diagrams of liquid-vapor equilibrium in a binary water-aliphatic aldehyde system.

  1. Improving plant functional groups for dynamic models of biodiversity: at the crossroads between functional and community ecology

    PubMed Central

    Isabelle, Boulangeat; Pauline, Philippe; Sylvain, Abdulhak; Roland, Douzet; Luc, Garraud; Sébastien, Lavergne; Sandra, Lavorel; Jérémie, Van Es; Pascal, Vittoz; Wilfried, Thuiller

    2013-01-01

    The pace of on-going climate change calls for reliable plant biodiversity scenarios. Traditional dynamic vegetation models use plant functional types that are summarized to such an extent that they become meaningless for biodiversity scenarios. Hybrid dynamic vegetation models of intermediate complexity (hybrid-DVMs) have recently been developed to address this issue. These models, at the crossroads between phenomenological and process-based models, are able to involve an intermediate number of well-chosen plant functional groups (PFGs). The challenge is to build meaningful PFGs that are representative of plant biodiversity, and consistent with the parameters and processes of hybrid-DVMs. Here, we propose and test a framework based on few selected traits to define a limited number of PFGs, which are both representative of the diversity (functional and taxonomic) of the flora in the Ecrins National Park, and adapted to hybrid-DVMs. This new classification scheme, together with recent advances in vegetation modeling, constitutes a step forward for mechanistic biodiversity modeling. PMID:24403847

  2. Determination of odour threshold concentrations and dose-response relations in water of several minor disinfection by-products: aldehydes and alkyl nitriles.

    PubMed

    Fabrellas, C; Matia, L; Ventura, F

    2004-01-01

    The odour threshold concentrations (OTCs) levels of aldehydes and alkyl nitriles, two groups of disinfection by-products of water treatment, have been studied in order to know if some of these compounds can be associated with off-flavour events. For aldehydes, as a result of the values obtained, which are in the low microg/L range, it is possible that they are related to these events. This is not the case for the other group, alkyl nitriles, with very high OTC values.

  3. Tree Diametric Increment and Litterfall Production in an Eastern Amazonian Forest: the Role of Functional Groups

    NASA Astrophysics Data System (ADS)

    Camargo, P. B. D.; Ferreira, M. L.; Oliveira Junior, R. C.; Saleska, S. R.

    2014-12-01

    Tree growth is a biotic variable of great importance in understanding the dynamics of tree communities and may be used as a tool in studies of biological or climate modeling. Some climate models predict more recurrent climate anomalies in this century, which may alter the functioning of tropical forests with serious structural and demographic implications. The present study aimed to evaluate the profile of tree growth and litterfall production in an eastern Amazon forest, which has suffered recent climatic disturbances. We contrasted different functional groups based on wood density (stem with 0.55; 0.56-0.7; >0.7 g cm-3), light availability (crown illumination index; high illuminated crown - IIC1 until shaded crown - IIC5), and, size class (trees 10-22.5; 22.6-35; 35.1-55; 55,1-90; >90 cm dbh). Tree diameter increment was monthly measured from November 2011 to September 2013 by using dendrometer bands installed on 850 individuals from different families. Litterfall was collected in 64 circular traps, oven dried and weighed, separated into leaves, twigs, reproductive parts and miscellaneous. During the rainy season the sampled trees had the highest rates of tree diametric increment. When analyzing the data by functional groups, large trees had faster growth, but when grouped by wood density, trees with wood density up to 0.55 and between 0.56 and 0.7 g cm-3 had the fastest rates of growth. When grouped by crown illumination index, trees exposed to higher levels of light grew more in comparison to partially shaded trees. Maximum daily air temperature and precipitation were the most important environmental variables in determining the diametric increment profile of the trees. Litterfall production was estimated to be 7.1 Mg ha-1.year-1 and showed a strong seasonal pattern, with dry season production being higher than in the rainy season. Leaves formed the largest fraction of the litterfall, followed by twigs, reproductive parts, and finally miscellaneous. These

  4. Polycomb Group (PcG) Proteins and Human Cancers: Multifaceted Functions and Therapeutic Implications

    PubMed Central

    Wang, Wei; Qin, Jiang-Jiang; Voruganti, Sukesh; Nag, Subhasree; Zhou, Jianwei; Zhang, Ruiwen

    2016-01-01

    Polycomb group (PcG) proteins are transcriptional repressors that regulate several crucial developmental and physiological processes in the cell. More recently, they have been found to play important roles in human carcinogenesis and cancer development and progression. The deregulation and dysfunction of PcG proteins often lead to blocking or inappropriate activation of developmental pathways, enhancing cellular proliferation, inhibiting apoptosis, and increasing the cancer stem cell population. Genetic and molecular investigations of PcG proteins have long been focused on their PcG functions. However, PcG proteins have recently been shown to exert non-polycomb functions, contributing to the regulation of diverse cellular functions. We and others have demonstrated that PcG proteins regulate the expression and function of several oncogenes and tumor suppressor genes in a PcG-independent manner, and PcG proteins are associated with the survival of patients with cancer. In this review, we summarize the recent advances in the research on PcG proteins, including both the polycomb-repressive and non-polycomb functions. We specifically focus on the mechanisms by which PcG proteins play roles in cancer initiation, development, and progression. Finally, we discuss the potential value of PcG proteins as molecular biomarkers for the diagnosis and prognosis of cancer, and as molecular targets for cancer therapy. PMID:26227500

  5. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are received... AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Production of Wine § 24.183 Use...

  6. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are received... AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL WINE Production of Wine § 24.183 Use...

  7. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are received... AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Production of Wine § 24.183 Use...

  8. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are received... AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL WINE Production of Wine § 24.183 Use...

  9. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are received... AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Production of Wine § 24.183 Use...

  10. Bronchodilator activity of xanthine derivatives substituted with functional groups at the 1- or 7-position.

    PubMed

    Miyamoto, K; Yamamoto, Y; Kurita, M; Sakai, R; Konno, K; Sanae, F; Ohshima, T; Takagi, K; Hasegawa, T; Iwasaki, N

    1993-05-14

    Xanthine derivatives with several functional groups at the 1- or 7-position were synthesized, and their pharmacological activities in guinea pigs were studied. In general, the in vitro tracheal relaxant action and positive chronotropic action of 3-propylxanthines were increased by substitutions with nonpolar functional groups at the 1-position, but decreased by any substitution at the 7-position. On the other hand, because positive chronotropic actions of substituents with allyl, aminoalkyl, alkoxyalkyl, and normal alkyl groups were much less than tracheal muscle became very high with substitutions of 3'-butenyl, (dimethylamino)ethyl, 2'-ethoxyethyl, 3'-methoxypropyl, and n-propyl groups at the 1-position and of 2'-ethoxyethyl, 2'-oxopropyl, and n-propyl groups at the 7-position, compared with theophylline and the corresponding unsubstituted xanthines, 3-propylxanthine and 1-methyl-3-propylxanthine. When compounds were intraduodenally administered to the guinea pig, 1-(2'-ethoxyethyl)-, 1-(3'-methoxypropyl)-, 1-(3'-butenyl)-, and 1-[(dimethylamino)-ethyl]-3-propylxanthines, 1-methyl-7-(2'-oxopropyl)-3-propylxanthine, and denbufylline (1,3-di-n-butyl-7-(2'-oxopropyl)xanthine) effectively inhibited the acetylcholine-induced bronchospasm without heart stimulation or central nervous system-stimulation at the effective dosage range. Particularly, the bronchodilatory effect of 1-(2'-ethoxyethyl)-3-propylxanthine was much stronger and more continuous than those of theophylline and pentoxifylline. On the other hand, there were certain relationships among the in vitro tracheal relaxant activities of these compounds, their affinities for adenosine (A1) receptors in the brain membrane, and their inhibition of cyclic AMP-phosphodiesterase (PDE) in the tracheal muscle. The affinity for A2 receptors of these compounds was very low or negligible. This suggests that both the action on A1 receptors or interaction with adenosine and the cyclic AMP-PDE inhibitory activity contribute

  11. Combinatorial approach to determine functional group effects on lipidoid-mediated siRNA delivery.

    PubMed

    Mahon, Kerry P; Love, Kevin T; Whitehead, Kathryn A; Qin, June; Akinc, Akin; Leshchiner, Elizaveta; Leshchiner, Ignaty; Langer, Robert; Anderson, Daniel G

    2010-08-18

    The application of RNA interference (RNAi), either in the clinic or in the laboratory, requires safe and effective delivery methods. Here, we develop a combinatorial approach to synthesize a library of delivery vectors based on two lipid-like substrates with known siRNA delivery capabilities. Members of this library have a mixture of lipid-like tails and feature appendages containing hydroxyl, carbamate, ether, or amine functional groups as well as variations in alkyl chain length and branching. Using a luciferase reporter system in HeLa cells, we studied the relationship between lipid chemical modification and delivery performance in vitro. The impact of the functional group was shown to vary depending on the overall amine content and tail number of the delivery vector. Additionally, in vivo performance was evaluated using a Factor VII knockdown assay. Two library members, each containing ether groups, were found to knock down the target protein at levels comparable to those of the parent delivery vector. These results demonstrate that small chemical changes to the delivery vector impact knockdown efficiency and cell viability both in vitro and in vivo. The work described here identifies new materials for siRNA delivery and provides new insight into the parameters for optimized chemical makeup of lipid-like siRNA delivery materials.

  12. Littelmann path model for geometric crystals, Whittaker functions on Lie groups and Brownian motion

    NASA Astrophysics Data System (ADS)

    Chhaibi, Reda

    2013-02-01

    Generally speaking, this thesis focuses on the interplay between the representations of Lie groups and probability theory. It subdivides into essentially three parts. In a first rather algebraic part, we construct a path model for geometric crystals in the sense of Berenstein and Kazhdan, for complex semi-simple Lie groups. We will mainly describe the algebraic structure, its natural morphisms and parameterizations. The theory of total positivity will play a particularly important role. Then, we anticipate on the probabilistic part by exhibiting a canonical measure on geometric crystals. It uses as ingredients the superpotential for the flag manifold and a measure invariant under the crystal actions. The image measure under the weight map plays the role of Duistermaat-Heckman measure. Its Laplace transform defines Whittaker functions, providing an interesting formula for all Lie groups. Then it appears clearly that Whittaker functions are to geometric crystals, what characters are to combinatorial crystals. The Littlewood-Richardson rule is also exposed. Finally we present the probabilistic approach that allows to find the canonical measure. It is based on the fundamental idea that the Wiener measure will induce the adequate measure on the algebraic structures through the path model. In the last chapter, we show how our geometric model degenerates to the continuous classical Littelmann path model and thus recover known results. For example, the canonical measure on a geometric crystal of highest weight degenerates into a uniform measure on a polytope, and recovers the parameterizations of continuous crystals.

  13. Gyrinidal: A Sesquiterpenoid Aldehyde from the Defensive Glands of Gyrinid Beetles*

    PubMed Central

    Meinwald, J.; Opheim, K.; Eisner, T.

    1972-01-01

    Three species of gyrinid beetles (Gyrinus ventralis, Dineutes hornii, and D. serrulatus) have been found to produce the nor-sesquiterpenoid aldehyde gyrinidal in the secretion of their pygidial defensive glands. This highly functionalized terpene is shown to be (E,E,E)-3,7-dimethyl-8,11-dioxo-2,6,9-dodecatrienal on the basis of spectral evidence and chemical degradation. While a very wide range of sesquiterpenoid structures occur in nature, gyrinidal appears to be the most highly oxidized acyclic sesquiterpene known. Images PMID:4504334

  14. Architectural and Functional Diversity of Polycomb Group Response Elements in Drosophila

    PubMed Central

    Brown, J. Lesley; Kassis, Judith A.

    2013-01-01

    Polycomb group response elements (PREs) play an essential role in gene regulation by the Polycomb group (PcG) repressor proteins in Drosophila. PREs are required for the recruitment and maintenance of repression by the PcG proteins. PREs are made up of binding sites for multiple DNA-binding proteins, but it is still unclear what combination(s) of binding sites is required for PRE activity. Here we compare the binding sites and activities of two closely linked yet separable PREs of the Drosophila engrailed (en) gene, PRE1 and PRE2. Both PRE1 and PRE2 contain binding sites for multiple PRE–DNA-binding proteins, but the number, arrangement, and spacing of the sites differs between the two PREs. These differences have functional consequences. Both PRE1 and PRE2 mediate pairing-sensitive silencing of mini-white, a functional assay for PcG repression; however, PRE1 requires two binding sites for Pleiohomeotic (Pho), whereas PRE2 requires only one Pho-binding site for this activity. Furthermore, for full pairing-sensitive silencing activity, PRE1 requires an AT-rich region not found in PRE2. These two PREs behave differently in a PRE embryonic and larval reporter construct inserted at an identical location in the genome. Our data illustrate the diversity of architecture and function of PREs. PMID:23934890

  15. Argos and Spitz group genes function to regulate midline glial cell number in Drosophila embryos.

    PubMed

    Stemerdink, C; Jacobs, J R

    1997-10-01

    The midline glia of the Drosophila embryonic nerve cord undergo a reduction in cell number after facilitating commissural tract morphogenesis. The numbers of midline glia entering apoptosis at this stage can be increased by a loss or reduction of function in genes of the spitz group or Drosophila EGF receptor (DER) pathway. Argos, a secreted molecule with an atypical EGF motif, is postulated to function as a DER antagonist. In this work, we assess the role of argos in the determination of midline glia cell number. Although all midline glia express DER, argos expression is restricted to the midline glia which do not enter apoptosis. Fewer midline glia enter apoptosis in embryos lacking argos function. Ectopic expression of argos is sufficient to remove all DER-expressing midline glia from the nerve cord, even those that already express argos. DER expression is not terminated in the midline glia after spitz group signaling triggers changes in gene expression. It is therefore likely that an attenuation of DER signaling by Argos is integrated with the augmentation of DER signaling by Spitz throughout the period of reduction of midline glia number. We suggest that signaling by Spitz but not Argos is restricted to adhesive junctions. In this manner, midline glia not forming signaling junctions remain sensitive to juxtacrine Argos signaling, while an autocrine Argos signal is excluded by the adhesive junction.

  16. The synthesis of desired functional groups on PEI microgel particles for biomedical and environmental applications

    NASA Astrophysics Data System (ADS)

    Sahiner, Nurettin; Demirci, Sahin; Sahiner, Mehtap; Al-Lohedan, Hamad

    2015-11-01

    Polyethyleneimine (PEI) microgels were synthesized by micro emulsion polymerization technique and converted to positively charged forms by chemical treatments with various modifying agents with different functional groups, such as 2-bromoethanol (-OH), 4-bromobutyronitrile (-CN), 2-bromoethylamine hydrobromide (-NH2), and glycidol (-OH). The functionalization of PEI microgels was confirmed by FT-IR, TGA and zeta potential measurements. Furthermore, a second modification of the modified PEI microgels was induced on 4-bromo butyronitrile-modified PEI microgels (PEI-CN) by amidoximation, to generate new functional groups on the modified PEI microgels. The PEI and modified PEI microgels were also tested for their antimicrobial effects against various bacteria such as Bacillus subtilis ATCC 6633, Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 25323. Moreover, the PEI-based particles were used for removal of organic dyes such as methyl orange (MO) and congo red (CR). The absorption capacity of PEI-based microgels increased with modification from 101.8 mg/g to 218.8 mg/g with 2-bromoethylamine, 216.2 m/g with 1-bromoethanol, and 224.5 mg/g with 4-bromobutyronitrile for MO. The increase in absorption for CR dyes was from 347.3 mg/g to 390.4 mg/g with 1-bromoethanol, 399.6 mg/g with glycidol, and 349.9 mg/g with 4-bromobutyronitrile.

  17. 14 CFR Section 11 - Functional Classification-Operating Expenses of Group II and Group III Air Carriers

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... operations. b. This subfunction shall not include expenses related to financial accounting, purchasing or... contribute to more than a single operating function such as general financial accounting activities... accounting year. Allocations of maintenance burden to capital projects, and service sales to others shall...

  18. Lactic acid bacteria producing B-group vitamins: a great potential for functional cereals products.

    PubMed

    Capozzi, Vittorio; Russo, Pasquale; Dueñas, María Teresa; López, Paloma; Spano, Giuseppe

    2012-12-01

    Wheat contains various essential nutrients including the B group of vitamins. However, B group vitamins, normally present in cereals-derived products, are easily removed or destroyed during milling, food processing or cooking. Lactic acid bacteria (LAB) are widely used as starter cultures for the fermentation of a large variety of foods and can improve the safety, shelf life, nutritional value, flavor and overall quality of the fermented products. In this regard, the identification and application of strains delivering health-promoting compounds is a fascinating field. Besides their key role in food fermentations, several LAB found in the gastrointestinal tract of humans and animals are commercially used as probiotics and possess generally recognized as safe status. LAB are usually auxotrophic for several vitamins although certain strains of LAB have the capability to synthesize water-soluble vitamins such as those included in the B group. In recent years, a number of biotechnological processes have been explored to perform a more economical and sustainable vitamin production than that obtained via chemical synthesis. This review article will briefly report the current knowledge on lactic acid bacteria synthesis of vitamins B2, B11 and B12 and the potential strategies to increase B-group vitamin content in cereals-based products, where vitamins-producing LAB have been leading to the elaboration of novel fermented functional foods. In addition, the use of genetic strategies to increase vitamin production or to create novel vitamin-producing strains will be also discussed.

  19. Role of functional groups in fiber in the binding of zinc

    SciTech Connect

    Jiang, K.

    1986-03-01

    The binding of zinc by purified cellulose, xylan, methylated xylan, pectin and methylated pectin was measured in vitro. Methylated xylan and methylated pectin were prepared chemically from xylan and pectin, respectively, to block hydroxyl and carboxyl groups. Comparison of zinc binding capacities was made between xylan and methylated xylan, and between pectin and methylated pectin to assess the role of the two functional groups in binding minerals. The binding of zinc was conducted at pH 2.6, 4.0, 5.4 and 6.8 in various concentrations of ZnSO/sub 4/ solution containing /sup 65/Zn using a dialysis system for water-soluble pectin and an incubation-centrifugation model for the other four water-insoluble fibers. The results showed that zinc binding by each fiber was pH dependent and it increased from pH 2.6 to 6.8 (p < 0.001). At pH 6.8, % Zn bound to fiber decreased as concentration of ZnSO/sub 4/ increased from 1 ..mu..M to 96 ..mu..M (p less than or equal to 0.01). mean zinc binding ratio of pectin to methylated xylan was 5.1, whereas the ratio of pectin t methylated pectin was only 1.7. This suggests that the hydroxyl group in xylan plays a more important role than the carboxyl group in pectin in the binding of zinc.

  20. Submerged vegetation removal promotes shift of dominant phytoplankton functional groups in a eutrophic lake.

    PubMed

    Dong, Jing; Yang, Kai; Li, Shuangshuang; Li, Genbao; Song, Lirong

    2014-08-01

    Historical data indicate that the dominance of submerged plants in Dianchi Lake in the 1960s was characterized by low algal density with dominance of non-toxic group J (Scenedesmus, Pediastrum, etc.). The removal of submerged plants, which began in the 1970s, resulted in the expansion of bloom-forming Microcystis (group M). Laboratory experiments suggested that Microcystis aeruginosa was inclined to grow and develop at elevated temperatures. The growth of Scenedesmus obliquus was slower than that of co-cultivated M. aeruginosa in the absence of Ceratophyllum demersum, especially at higher temperatures. The existence of submerged plant C. demersum could inhibit the growth of the harmful algae M. aeruginosa and this inhibitory effect by C. demersum was enhanced with an increase in temperature. Instead, with C. demersum, the growth of S. obliquus was not inhibited, but the co-cultivated M. aeruginosa was eliminated in a short time. Combined with the historical data and laboratory experiments, it was indicated that the submerged plants might play important roles in the dominance of the non-toxic group J in the historical succession. Consequently, the introduction of the submerged plant such as C. demersum might alter the dominant phytoplankton functional groups from M to J and benefit the restoration of the eutrophic lake.

  1. Oxidative metabolic pathway of lenvatinib mediated by aldehyde oxidase.

    PubMed

    Inoue, Kazuko; Mizuo, Hitoshi; Kawaguchi, Shinki; Fukuda, Katsuyuki; Kusano, Kazutomi; Yoshimura, Tsutomu

    2014-08-01

    Lenvatinib is a multityrosine kinase inhibitor that inhibits vascular endothelial growth factor receptors, and is being developed as an anticancer drug. P450s are involved in one of the elimination pathways of lenvatinib, and mono-oxidized metabolites, such as N-oxide (M3) and desmethylated metabolite (M2), form in rats, dogs, monkeys, and humans. Meanwhile, two other oxidative metabolites are produced only in monkey and human liver S9 fractions, and their structures have been identified using high-resolution mass spectrometry as a quinolinone form of lenvatinib (M3') and a quinolinone form of desmethylated lenvatinib (M2'). The formation of M3' from lenvatinib occurred independently of NADPH and was effectively inhibited by typical inhibitors of aldehyde oxidase, indicating the involvement of aldehyde oxidase, but not P450s, in this pathway. M2' was a dioxidized metabolite arising from a combination of mono-oxidation and desmethylation and could only be produced from M2 in a NADPH-independent manner; M2' could not be generated from M3 or M3'. These results suggested that M2' is formed from lenvatinib by a unique two-step pathway through M2. Although both lenvatinib and M2 were substrates for aldehyde oxidase, an enzyme kinetic study indicated that M2 was a much more favorable substrate than lenvatinib. No inhibitory activities of lenvatinib, M2', or M3' and no significant inhibitory activities of M2 or M3 on aldehyde oxidase were observed, suggesting a low possibility of drug-drug interactions in combination therapy with substrates of aldehyde oxidase.

  2. Mechanistic considerations on contact-active antimicrobial surfaces with controlled functional group densities.

    PubMed

    Bieser, Arno M; Tiller, Joerg C

    2011-04-08

    A series of N-alkyl-N,N-dimethyldeoxyammonium celluloses is synthesized by converting tosyl celluloses with DBA and DDA, respectively. Surface coatings with these water-insoluble derivatives contain well-defined densities of quaternary ammonium functions and nonactive hydrophobic and hydrophilic groups. It is shown that the antimicrobial activity of such surfaces against S. aureus requires a delicate balance between DDA, BDA, and hydrophobic groups. A mechanism is proposed that involves the selective adhesion of anionic phospholipids from the bacterial cell membrane. This so-called phospholipid sponge effect is supported by the fact that all coatings could be deactivated by treatment with SDS or negatively charged phospholipids, but not with neutral phospholipids.

  3. Natural molecular fragments, functional groups, and holographic constraints on electron densities.

    PubMed

    Mezey, Paul G

    2012-06-28

    One of the tools of the shape analysis of molecular electron densities, the Density Threshold Progression Approach used in Shape Group studies can also serve as a criterion for the selection of "natural" molecular fragments, relevant to functional group comparisons, reactivity studies, as well as to the study of levels of relative "autonomy" of various molecular regions. The relevance of these approaches to the fragment-based studies of large molecules, such as biopolymers and nanostructures is emphasized, and the constraints represented by the holographic electron density theorem to this and alternative recent fragment approaches are discussed. The analogies with potential energy hypersurface analysis using the Energy Threshold Progression Approach and connections to level set methods are discussed, and the common features of these seemingly distant problems are described.

  4. Oxidative versus Non-oxidative Decarboxylation of Amino Acids: Conditions for the Preferential Formation of Either Strecker Aldehydes or Amines in Amino Acid/Lipid-Derived Reactive Carbonyl Model Systems.

    PubMed

    Zamora, Rosario; León, M Mercedes; Hidalgo, Francisco J

    2015-09-16

    Comparative formation of both 2-phenylethylamine and phenylacetaldehyde as a consequence of phenylalanine degradation by carbonyl compounds was studied in an attempt to understand if the amine/aldehyde ratio can be changed as a function of reaction conditions. The assayed carbonyl compounds were selected because of the presence in the chain of both electron-donating and electron-withdrawing groups and included alkenals, alkadienals, epoxyalkenals, oxoalkenals, and hydroxyalkenals as well as lipid hydroperoxides. The obtained results showed that the 2-phenylethylamine/phenylacetaldehyde ratio depended upon both the carbonyls and the reaction conditions. Thus, it can be increased using electron-donating groups in the chain of the carbonyl compound, small amounts of carbonyl compound, low oxygen content, increasing the pH, or increasing the temperature at pH 6. Opposed conditions (use of electron-withdrawing groups in the chain of the carbonyl compound, large amounts of carbonyl compound, high oxygen contents, low pH values, and increasing temperatures at low pH values) would decrease the 2-phenylethylamine/phenylacetaldehyde ratio, and the formation of aldehydes over amines in amino acid degradations would be favored.

  5. Acidity of the amidoxime functional group in aqueous solution. A combined experimental and computational study

    SciTech Connect

    Mehio, Nada; Lashely, Mark A.; Nugent, Joseph W.; Tucker, Lyndsay; Correia, Bruna; Do-Thanh, Chi-Linh; Dai, Sheng; Hancock, Robert D.; Bryantsev, Vyacheslav S.

    2015-01-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. It has been demonstrated repeatedly in the literature that the success of these materials is due to the amidoxime functional group. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pKa values that have been reported for the amidoxime functional group in the literature. To resolve this existing controversy we investigated the pKa values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopic titrations to measure the pKa values of representative amidoximes, acetamidoxime and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pKa values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance with a mean absolute error of 0.33 pKa units and 0.35 pKa units, respectively, and a root mean square deviation of 0.46 pKa units and 0.45 pKa units, respectively. Finally, we employ our two best methods to predict the pKa values of promising, uncharacterized amidoxime ligands. Hence, our study provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents used to mine uranium from seawater.

  6. Acidity of the amidoxime functional group in aqueous solution. A combined experimental and computational study

    DOE PAGES

    Mehio, Nada; Lashely, Mark A.; Nugent, Joseph W.; ...

    2015-01-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. It has been demonstrated repeatedly in the literature that the success of these materials is due to the amidoxime functional group. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pKa values that have been reported for the amidoxime functional group in the literature. To resolve this existing controversy we investigated the pKa values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopicmore » titrations to measure the pKa values of representative amidoximes, acetamidoxime and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pKa values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance with a mean absolute error of 0.33 pKa units and 0.35 pKa units, respectively, and a root mean square deviation of 0.46 pKa units and 0.45 pKa units, respectively. Finally, we employ our two best methods to predict the pKa values of promising, uncharacterized amidoxime ligands. Hence, our study provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents used to mine uranium from seawater.« less

  7. Ecological Significance of a Geomorphic Stream Classification: Species and Functional Group Composition of Riparian Plant Communities

    NASA Astrophysics Data System (ADS)

    Shaw, J. R.; Cooper, D. J.

    2014-12-01

    We tested the ecological significance of a geomorphic classification of Sonoran Desert ephemeral stream channels based on channel plan-form, degree of lateral confinement, and boundary material composition. This typology has been shown to discriminate among channel geometry and hydraulic characteristics for bedrock, bedrock with alluvium, incised alluvium, braided, and piedmont headwater channels. We examined stream reach-scale relationships of geomorphic stream types to the relative cover and density of perennial plant species and functional groups, and identified the dominant fluvial drivers, within riparian communities at 101 ephemeral stream reaches on the U.S. Army Yuma Proving Ground and Barry M. Goldwater Air Force Range in southwestern Arizona, USA. Nonparametric multivariate analysis of variance showed that species and functional group composition differed significantly among geomorphic stream types, both in terms of relative cover and density. Partitioning of among-site multivariate dissimilarity revealed that species compositional differences between stream types were caused largely by variation in the cover and density of the most common members of the regional flora. Distinctive functional group compositi