Sample records for remarkably diastereoselective synthesis

  1. Diastereoselective Synthesis of trans-beta-Lactams Using a Simple Multifunctional Catalyst.

    Abraham, Ciby J; Paull, Daniel H; Dogo-Isonagie, Cajetan; Lectka, Thomas


    A catalytic, highly diastereoselective process for the synthesis of trans-beta-lactams is reported. This system is based on a phosphonium fluoride precatalyst that both activates the nucleophile and directs the reaction process for high yield and diastereoselectivity.

  2. Diastereoselective Ugi reaction for the synthesis of unnatural amino esters

    Rafael Oliveira Rocha


    Full Text Available Multicomponent Reactions (MCR are useful reactions to obtain complex products by the simple mixture of 3 or more reactants. The classic Ugi reaction (4-UCR involves a mixture of an amine, aldehyde, isocyanide and a carboxylic acid, giving peptoides as products. Some modifications of this reaction have been reported, among which the use of amino acids and Lewis acids, such as titanium (IV chloride, to induce stereoselectivity in good ratio. In this work we demonstrate the efficiency of different Lewis acids in the modified Ugi reaction and good levels of diastereoselectivity and yields in the synthesis of unnatural secondary amino esters.

  3. Diastereoselective Synthesis of trans-β-Lactams Using a Simple Multifunctional Catalyst

    Abraham, Ciby J.; Paull, Daniel H.; Dogo-Isonagie, Cajetan; Lectka, Thomas


    A catalytic, highly diastereoselective process for the synthesis of trans-β-lactams is reported. This system is based on a phosphonium fluoride precatalyst that both activates the nucleophile and directs the reaction process for high yield and diastereoselectivity. PMID:20442797

  4. The diastereoselective synthesis of octahedral cationic iridium hydride complexes with a stereogenic metal centre.

    Humbert, Nicolas; Mazet, Clément


    We report herein the highly diastereoselective synthesis of octahedral cationic Ir(iii) hydride complexes with a stereogenic metal centre following various strategies. The configurational stability of these compounds has also been investigated.

  5. Diastereoselective synthesis of novel aza-diketopiperazines via a domino cyclohydrocarbonylation/addition process.

    Regenass, Pierre; Margathe, Jean-François; Mann, André; Suffert, Jean; Hibert, Marcel; Girard, Nicolas; Bonnet, Dominique


    Herein, we report an unprecedented, short and diastereo-selective synthesis of newly reported aza-diketopiperazine (aza-DKP) scaffolds starting from amino acids. The strategy is based on a Rh(I)-catalyzed hydroformylative cyclohydrocarbonylation of allyl-substituted aza-DKP, followed by a diastereoselective functionalization of the platform. This methodology allows the synthesis of novel bicyclic and tricyclic aza-DKP scaffolds incorporating six- or seven-membered rings, with potential applications in medicinal chemistry.

  6. Highly diastereoselective synthesis of quaternary α-trifluoromethyl α-amino acids from chiral imines of trifluoropyruvate.

    Min, Qiao-Qiao; He, Chun-Yang; Zhou, Haibing; Zhang, Xingang


    An efficient method for highly diastereoselective synthesis of quaternary α-trifluoromethyl α-amino acids was developed via indium mediated allylation of (R)-phenylglycinol methyl ether based imines of trifluoropyruvate in good yields with high diastereoselectivities at room temperature; to illustrate the application of this method in organic synthesis, 2-allyl-2-(trifluoromethyl) aziridine was prepared in an efficient manner.

  7. Highly diastereoselective synthesis of enantiopure β-trifluoromethyl β-amino alcohols from chiral trifluoromethyl oxazolidines (Fox).

    Simon, Julien; Chelain, Evelyne; Brigaud, Thierry


    The organolithium species addition to 2-hydroxymethyl fluorinated oxazolidines (Fox) provides a highly diastereoselective and straightforward route for the synthesis of enantiopure trifluoromethyl β-amino alcohols quaternarized at the β-position.

  8. Diastereoselective synthesis of substituted 2-amino-1,3-propanediols from Morita-Baylis-Hillman adducts

    Paioti, Paulo H.S.; Rezende, Patricia; Coelho, Fernando [Laboratorio de Sintese de Produtos Naturais e Farmacos, Instituto de Quimica, Universidade Estadual de Campinas (UNICAMP), SP (Brazil)


    We report herein a new diastereoselective approach to substituted 2-amino-1,3-propanediols with anti relative stereochemistry from Morita-Baylis-Hillman (MBH) adducts. These structural moieties have been used as intermediates for the synthesis of several compounds with relevant pharmacological and commercial interest. In this strategy, substituted anti 2-amino-1,3-propanediols were readily prepared via ozonolysis of allylic diols obtained from MBH adducts, followed by a diastereoselective reductive amination of the substituted 2-oxo-1,3-propanediols. To demonstrate the synthetic utility of these aminodiols, they were transformed into substituted oxazolidine-2-ones, which were also used in the indirect determination of the relative stereochemistry of the aminodiols. (author)

  9. Carbamoyl anion addition to N-sulfinyl imines: highly diastereoselective synthesis of α-amino amides.

    Reeves, Jonathan T; Tan, Zhulin; Herbage, Melissa A; Han, Zhengxu S; Marsini, Maurice A; Li, Zhibin; Li, Guisheng; Xu, Yibo; Fandrick, Keith R; Gonnella, Nina C; Campbell, Scot; Ma, Shengli; Grinberg, Nelu; Lee, Heewon; Lu, Bruce Z; Senanayake, Chris H


    Carbamoyl anions, generated from N,N-disubstituted formamides and lithium diisopropylamide, add with high diastereoselectivity to chiral N-sulfinyl aldimines and ketimines to provide α-amino amides. The methodology enables the direct introduction of a carbonyl group without the requirement of unmasking steps as with other nucleophiles. The products may be converted to α-amino esters or 1,2-diamines. Iterative application of the reaction enabled the stereoselective synthesis of a dipeptide. Spectroscopic and computational studies support an anion structure with η(2) coordination of lithium by the carbonyl group.

  10. Diastereoselective Synthesis of a Simplified Core of Rishirilide B.

    Mejorado, Lupe; Pettus, Thomas R R


    A route enabling the synthesis of the stereo-triad of rishirilide B (1) from 2-hydroxy-3-methylnaphthalene-1,4-dione, is reported. Key transformations include the regioselective 1,2-Grignard addition to a tautomeric mixture of o- and p-quinones, regioselective carbamoylation of a tautomeric mixture, and a synopsis of the methods explored to convert various terminal vinyl ethers into the corresponding carboxylic acid by cleavage.

  11. Diastereoselective synthesis of 3,4-dihydro-2H-pyran-4-carboxamides through an unusual regiospecific quasi-hydrolysis of a cyano group

    Mikhail Yu. Ievlev


    Full Text Available An efficient diastereoselective approach for the synthesis of functionalized 3,4-dihydro-2H-pyran-4-carboxamides with variable frame was developed based on the reaction of available 4-oxoalkane-1,1,2,2-tetracarbonitriles (adducts of TCNE and ketones with aldehydes in an acidic media. An unusual process of quasi hydrolysis of the cyano group was observed in the course of the described regio- and diastereoselective transformation.

  12. Post-Ugi gold-catalyzed diastereoselective domino cyclization for the synthesis of diversely substituted spiroindolines

    Amit Kumar


    Full Text Available An Ugi four-component reaction of propargylamine with 3-formylindole and various acids and isonitriles produces adducts which are subjected to a cationic gold-catalyzed diastereoselective domino cyclization to furnish diversely substituted spiroindolines. All the reactions run via an exo-dig attack in the hydroarylation step followed by an intramolecular diastereoselective trapping of the imminium ion. The whole sequence is atom economic and the application of a multicomponent reaction assures diversity.

  13. Domino Michael-Michael and Aldol-Aldol Reactions: Diastereoselective Synthesis of Functionalized Cyclohexanone Derivatives Containing Quaternary Carbon Center.

    Ghorai, Manas K; Halder, Sandipan; Das, Subhomoy


    A simple strategy for the synthesis of highly functionalized cyclohexanone derivatives containing an all-carbon quaternary center from α-(aryl/alkyl)methylidene-β-keto esters or β-diketones via a K-enolate mediated domino Michael-Michael reaction sequence with moderate to good yield and excellent diastereoselectivity (de > 99%) is described. Interestingly, Li-base mediated reaction of α-arylmethylidene-β-diketones affords functionalized 3,5-dihydroxy cyclohexane derivatives as the kinetically controlled products via a domino aldol-aldol reaction sequence with excellent diastereoselectivity. Li-enolates of the β-keto esters or β-diketones undergo facile domino Michael-Michael reaction with nitro-olefins to afford the corresponding nitrocyclohexane derivatives in good yields and excellent diastereoselectivity (de > 99%). The formation of the products and the observed stereoselectivity were explained by plausible mechanisms and supported by extensive computational study. An asymmetric version of the protocol was explored with (L)-menthol derived nonracemic substrates, and the corresponding nonracemic cyclohexanone derivatives containing an all-carbon quaternary center were obtained with excellent stereoselectivity (de, ee > 99%).

  14. Enantio- and Diastereoselective Synthesis of exo-Peroxyacetals: An Organocatalyzed Peroxyhemiacetalization/oxa-Michael Addition Cascade.

    Maity, Sanjay; Parhi, Biswajit; Ghorai, Prasanta


    An unprecedented enantioselective peroxyhemiacetalization/oxa-Michael addition cascade of ortho-formyl homochalcones has been developed using cinchona-alkaloid-based chiral bifunctional organocatalysts to provide cis-configured exo-peroxyacetals, a new class of organic peroxide, in good yields with excellent enantio- and diastereoselectivities. The resulting cis-configured exo-peroxyacetals were converted into the corresponding trans-configured peroxyacetals without affecting the enantioselectivity. Furthermore, the displacement of the peroxide moiety of exo-peroxyacetals with various nucleophiles has been demonstrated to afford 1,3-disubstituted isochromans with high diastereoselectivities and excellent enantioselectivities. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. An efficient green synthesis of dispirohydroquinolines via a diastereoselective one-pot eight-component reaction

    Sajjad Salahia; Malek Taher Maghsoodloua; Nourallah Hazeria; Mojtaba Lashkaria; Santiago Garcia-Granda; Laura Torre-Fernandez


    The one-pot eight-component reaction between Meldrum's acid, an aromatic aldehyde, and an aryl amine was achieved in the presence of citric acid catalyst. The corresponding dispirohydroquino-lines were obtained in good yields with excellent diastereoselectivity. This method is a combination of the Knoevenagel and Michael reactions.

  16. Diastereoselective dihydroxylation and regioselective deoxygenation of dihydropyranones: a novel protocol for the stereoselective synthesis of C1-C8 and C15-C21 subunits of (+)-discodermolide.

    Ramachandran, P Veeraraghavan; Prabhudas, Bodhuri; Chandra, J Subash; Reddy, M Venkat Ram


    Diastereoselective dihydroxylation of dihydropyranones and subsequent regioselective alpha-deoxygenation provides 1,3-trans-beta-hydroxy-delta-lactones stereoselectively. This protocol has been applied for the synthesis of C(1)-C(8) and C(15)-C(21) subunits of (+)-discodermolide.

  17. Synthesis of the cores of hypocrellin and shiraiachrome: diastereoselective 1,8-diketone aldol cyclization.

    O'Brien, Erin M; Li, Jingxian; Carroll, Patrick J; Kozlowski, Marisa C


    Intramolecular 1,8-diketone aldol reactions were studied as a tool for the construction of the seven-membered rings of hypocrellin and shiraiachrome. Conditions were identified to obtain the relative stereochemistries present in the two natural products with excellent diastereoselectivity. In addition, a nine-membered ring congener, which has yet to be observed in nature, formed with high selectivity when a hindered amine was used in conjunction with silazide bases.

  18. Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives

    Nelson Adam


    Full Text Available Abstract Background: Many polyhydroxylated piperidines are inhibitors of the oligosaccharide processing enzymes, glycosidases and glycosyltransferases. Aza-C-linked disaccharide mimetics are compounds in which saturated polyhydroxylated nitrogen and oxygen heterocycles are linked by an all-carbon tether. The saturated oxygen heterocycle has the potential to mimic the departing sugar in a glycosidase-catalysed reaction and aza-C-linked disaccharide mimetics may, therefore, be more potent inhibitors of these enzymes. Results: The scope, limitations and diastereoselectivity of the dihydroxylation of stereoisomeric 2-butyl-1-(toluene-4-sulfonyl-1,2,3,6-tetrahydro-pyridin-3-ols is discussed. In the absence of a 6-substituent on the piperidine ring, the Upjohn (cat. OsO4, NMO, acetone-water and Donohoe (OsO4, TMEDA, CH2Cl2 conditions allow complementary diastereoselective functionalisation of the alkene of the (2R*,3R* diastereoisomer. However, in the presence of a 6-substituent, the reaction is largely controlled by steric effects with both reagents. The most synthetically useful protocols were exploited in the two-directional synthesis of aza-C-linked disaccharide analogues. A two-directional oxidative ring expansion was used to prepare bis-enones such as (2R,6S,2'S-6-methoxy-2-(6-methoxy-3-oxo-3,6-dihydro-2H-pyran-2-ylmethyl-1-(toluene-4-sulfonyl-1,6-dihydro-2H-pyridin-3-one from the corresponding difuran. Selective substitution of its N,O acetal was possible. The stereochemical outcome of a two-directional Luche reduction step was different in the two heterocyclic rings, and depended on the conformation of the ring. Finally, two-directional diastereoselective dihydroxylation yielded seven different aza-C-linked disaccharide analogues. Conclusion: A two-directional approach may be exploited in the synthesis of aza-C-linked disaccharide mimetics. Unlike previous approaches to similar molecules, neither of the heterocyclic rings is directly derived

  19. Diastereoselective synthesis of potent antimalarial cis-β-lactam agents through a [2 + 2] cycloaddition of chiral imines with a chiral ketene.

    Jarrahpour, Aliasghar; Ebrahimi, Edris; Sinou, Véronique; Latour, Christine; Brunel, Jean Michel


    The effect of double asymmetric induction for the synthesis of new cis-β-lactams by [2 + 2] cycloaddition reactions of chiral imines with a chiral ketene was investigated. The cycloaddition reaction was found to be totally diastereoselective leading exclusively to the formation of the cis-β-lactam derivatives. The newly synthesized cycloadducts were evaluated for their antimalarial activities against Plasmodium falciparum K14 resistant strain with moderate to excellent IC50 values varying from 8 to 50 μM. Of the fifteen β-lactams tested, four showed IC50 ≤ 11 μM. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  20. Diastereoselective Allylation of "N"-"Tert"-Butanesulfinyl Imines: An Asymmetric Synthesis Experiment for the Undergraduate Organic Laboratory

    Chen, Xiao-Yang; Sun, Li-Sen; Gao, Xiang; Sun, Xing-Wen


    An asymmetric synthetic experiment that encompasses both diastereoselectivity and enantioselectivity is described. In this experiment, Zn-mediated allylation of an ("R")-"N"-"tert"-butanesulfinyl imine is first performed to obtain either diastereomer using two different solvent systems, followed by oxidation of the…

  1. Highly Efficient and Diastereoselective Synthesis of New Pyrazolylpyrrolizine and Pyrazolylpyrrolidine Derivates by a Three-Component Domino Process

    Jairo Quiroga


    Full Text Available Diastereoselective reactions between 4-formylpyrazoles, N-substituted maleimides and glycine derivates led to new series of pyrazolyldipyrrolo [3,4-a:3',4'-f]pyrrolizines and pyrazolylpyrrolo[3,4-c]pyrroles in good yields. The reactions proceeded by a domino process through azomethine ylides formed in situ via a 1,3-dipolar cycloaddition reaction.

  2. Nonradical Zinc-Barbier Reaction for Diastereoselective Synthesis of Vicinal Amino Alcohols

    Keinicke, Lise Edelmann; Fristrup, Peter; Norrby, Per-Ola


    A new protocol for the synthesis of vicinal amino alcohols is described. The method employs a Barbier-type reaction between an imine and 3-benzoyloxyallyl bromide in the presence of zinc metal. The addition products are debenzoylated to afford amino alcohols in good yields and with diastereomeric...... ratios greater than 85:15 in favor of the anti isomer. A Hammett study has been performed which strongly indicates that the allylation does not follow a radical mechanism, but instead an organometallic reagent is formed which subsequently reacts with the imine. A computational study based...

  3. Expeditious diastereoselective synthesis of elaborated ketones via remote Csp3-H functionalization

    Shu, Wei; Lorente, Adriana; Gómez-Bengoa, Enrique; Nevado, Cristina


    The quest for selective C-H functionalization reactions, able to provide new strategic opportunities for the rapid assembly of molecular complexity, represents a major focus of the chemical community. Examples of non-directed, remote Csp3-H activation to forge complex carbon frameworks remain scarce due to the kinetic stability and thus intrinsic challenge associated to the chemo-, regio- and stereoselective functionalization of aliphatic C-H bonds. Here we describe a radical-mediated, directing-group-free regioselective 1,5-hydrogen transfer of unactivated Csp3-H bonds followed by a second Csp2-H functionalization to produce, with exquisite stereoselectivity, a variety of elaborated fused ketones. This study demonstrates that aliphatic acids can be strategically harnessed as 1,2-diradical synthons and that secondary aliphatic C-H bonds can be engaged in stereoselective C-C bond-forming reactions, highlighting the potential of this protocol for target-oriented natural product and pharmaceutical synthesis.

  4. Expeditious diastereoselective synthesis of elaborated ketones via remote Csp3–H functionalization

    Shu, Wei; Lorente, Adriana; Gómez-Bengoa, Enrique; Nevado, Cristina


    The quest for selective C–H functionalization reactions, able to provide new strategic opportunities for the rapid assembly of molecular complexity, represents a major focus of the chemical community. Examples of non-directed, remote Csp3–H activation to forge complex carbon frameworks remain scarce due to the kinetic stability and thus intrinsic challenge associated to the chemo-, regio- and stereoselective functionalization of aliphatic C–H bonds. Here we describe a radical-mediated, directing-group-free regioselective 1,5-hydrogen transfer of unactivated Csp3–H bonds followed by a second Csp2–H functionalization to produce, with exquisite stereoselectivity, a variety of elaborated fused ketones. This study demonstrates that aliphatic acids can be strategically harnessed as 1,2-diradical synthons and that secondary aliphatic C–H bonds can be engaged in stereoselective C–C bond-forming reactions, highlighting the potential of this protocol for target-oriented natural product and pharmaceutical synthesis. PMID:28082736

  5. cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

    Dimpee Gogoi


    Full Text Available We have synthesized a series of cis-6a,7,8,12b-tetrahydro-6H-naphtho[2,1-c]chromen-6a-ols as B-ring-modified analogues of (±-brazilin. A completely regio- and cis-diastereoselective intramolecular Friedel–Crafts epoxy–arene cyclization of 1-tetralone-derived glycidyl ethers catalyzed by Brønsted acids was used as the key step. Our worries concerning the formation of cis–trans product mixtures and their probable conversion to naphthopyran derivatives via dehydration of the tertiary hydroxy group were laid to rest. Additionally, the angular hydroxy group of one of the synthesized products has been reductively removed by a diastereoselective method which should be useful in future for preparing libraries of chroman-fused tetralins with trans-stereochemistry at the ring junction.

  6. cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin.

    Gogoi, Dimpee; Devi, Runjun; Pahari, Pallab; Sarma, Bipul; Das, Sajal Kumar


    We have synthesized a series of cis-6a,7,8,12b-tetrahydro-6H-naphtho[2,1-c]chromen-6a-ols as B-ring-modified analogues of (±)-brazilin. A completely regio- and cis-diastereoselective intramolecular Friedel-Crafts epoxy-arene cyclization of 1-tetralone-derived glycidyl ethers catalyzed by Brønsted acids was used as the key step. Our worries concerning the formation of cis-trans product mixtures and their probable conversion to naphthopyran derivatives via dehydration of the tertiary hydroxy group were laid to rest. Additionally, the angular hydroxy group of one of the synthesized products has been reductively removed by a diastereoselective method which should be useful in future for preparing libraries of chroman-fused tetralins with trans-stereochemistry at the ring junction.

  7. Synthesis of donor-acceptor alkynylcyclopropanes by diastereoselective cyclopropanation of electron-deficient alkenes with alkoxyalkynyl Fischer carbene complexes.

    Barluenga, José; Fernández-Rodríguez, Manuel A; García-García, Patricia; Aguilar, Enrique; Merino, Isabel


    The reaction of electron-deficient alkenes with alkoxyalkynyl Fischer carbene complexes (FCCs) represents a straightforward route to a new type of captodative (donor-acceptor) alkynylcyclopropanes, which have been prepared in moderate to high yields and in a diastereoselective manner. Some studies regarding the employment of additives to facilitate the recovery of the metal moiety after the reaction are also described. Finally, the first example of a cyclopropanation reaction through employing Fischer carbene complexes under microwave irradiation is presented; this method proved to be an advantageous alternative to the thermal reaction.

  8. Practical synthesis of enantiomerically pure beta2-amino acids via proline-catalyzed diastereoselective aminomethylation of aldehydes.

    Chi, Yonggui; English, Emily P; Pomerantz, William C; Horne, W Seth; Joyce, Leo A; Alexander, Lane R; Fleming, William S; Hopkins, Elizabeth A; Gellman, Samuel H


    Proline-catalyzed diastereoselective aminomethylation of aldehydes using a chiral iminium ion, generated from a readily prepared precursor, provides alpha-substituted-beta-amino aldehydes with 85:15 to 90:10 dr. The alpha-substituted-beta-amino aldehydes can be reduced to beta-substituted-gamma-amino alcohols, the major diastereomer of which can be isolated via crystallization or column chromatography. The amino alcohols are efficiently transformed to protected beta2-amino acids, which are valuable building blocks for beta-peptides, natural products, and other interesting molecules. Because conditions for the aminomethylation and subsequent reactions are mild, beta2-amino acid derivatives with protected functional groups in the side chain, such as beta2-homoglutamic acid, beta2-homotyrosine, and beta2-homolysine, can be prepared in this way. The synthetic route is short, and purifications are simple; therefore, this method enables the preparation of protected beta2-amino acids in useful quantities.

  9. Diastereoselective Synthesis of 5-Hydroxy-8-methoxy-1-oxaspiro[5,5]undeca-7,10-diene-9-one

    Thomas W. Scully


    Full Text Available A short five steps synthesis of the title compound from vanillin is described. The racemic spiroether 7 was obtained in 61% yield and in >99% diastereomeric excess (by 1H-NMR from the corresponding phenolic derivative 3 by oxidation with lead (IV acetate.

  10. Diastereoselective Synthesis of γ-Substituted 2-Butenolides via (CDC)-Rh-Catalyzed Intermolecular Hydroalkylation of Dienes with Silyloxyfurans.

    Goldfogel, Matthew J; Roberts, Courtney C; Manan, Rajith S; Meek, Simon J


    Catalytic intermolecular hydroalkylation of dienes with silyloxyfuran nucleophiles is reported. Reactions are catalyzed by 5 mol % of a (CDC)-Rh complex and proceed in up to 87% yield and 6:1 dr (syn/anti) to provide allylic butenolides bearing vicinal stereocenters. Reactions proceed with terminal aryl and alkyl dienes and with modified silyl enol ether nucleophiles including a thiophenone variant. Utility of the products is demonstrated in the synthesis of a polypropionate anti,syn-stereotriad.

  11. An Enantio‐ and Diastereoselective Chemoenzymatic Synthesis of α‐Fluoro β‐Hydroxy Carboxylic Esters

    Howard, JK; Muller, M; A. Berry; A. Nelson


    Abstract The trans‐o‐hydroxybenzylidene pyruvate aldolase‐catalysed reactions between fluoropyruvate and many (hetero)aromatic aldehydes yield aldol adducts without subsequent dehydration. Treatment of the reaction products with hydrogen peroxide yields the corresponding syn‐configured α‐fluoro β‐hydroxy carboxylic acids which have >98 % ee. The overall chemoenzymatic approach, in which fluoropyruvate serves as a fluoroacetate equivalent, may be exploited in the synthesis of polar building bl...

  12. Tandem halogenation/Michael-initiated ring-closing reaction of α,β-unsaturated nitriles and activated methylene compounds: one-pot diastereoselective synthesis of functionalized cyclopropanes.

    Xin, Xiaoqing; Zhang, Qian; Liang, Yongjiu; Zhang, Rui; Dong, Dewen


    An efficient one-pot synthetic route to highly substituted cyclopropanes has been developed from readily available α,β-unsaturated nitriles and doubly activated methylene compounds under very mild conditions in a highly diastereoselective manner, which involves halogenation, Michael addition and intramolecular ring-closing reaction sequences.

  13. Diastereoselective synthesis and molecular docking studies of novel fused tetrahydropyridine derivatives as new inhibitors of HIV protease

    Mohammadi, Ali A.; Taheri, Salman; Amouzegar, Ali; Ahdenov, Reza; Halvagar, Mohammad Reza; Sadr, Ahmad Shahir


    An efficient one-pot, catalyst-free, and four-components procedure for the synthesis of novel 10b-hydroxy-4-nitro-5-phenyl-2,3,5,5a-tetrahydro-1H-imidazo[1,2-a]indeno[2,1-e]pyridin-6(10bH)-one derivatives from corresponding diamine, nitro ketene dithioacetal, aldehydes and 1,3-indandione in ethanol has been achieved upon a Knoevenagel condensation-Michael addition-tautomerism-cyclisation sequence. All the newly synthesized compounds were screened for molecular docking studies. Molecular docking studies were carried out using the crystal structure of HIV protease enzyme. Some of the compounds obtain minimum binding energy and good affinity toward the active pocket of HIV protease enzyme in compare with Saquinavir as a standard HIV protease inhibitor.

  14. Lewis acid promoted highly diastereoselective Petasis Borono-Mannich reaction: efficient synthesis of optically active β,γ-unsaturated α-amino acids.

    Li, Yi; Xu, Ming-Hua


    An efficient and straightforward method for the preparation of highly enantiomerically enriched β,γ-unsaturated α-amino acid derivatives by a Lewis acid promoted diastereoselective Petasis reaction of vinylboronic acid, N-tert-butanesulfinamide, and glyoxylic acid has been developed. The synthetic utilities of the approach were demonstrated by the rapid and convenient construction of challenging cyclopenta[c]proline derivatives. © 2012 American Chemical Society

  15. Diastereoselective Pictet-Spengler approach for the synthesis of pyrrolo[3,2-e][1,4]diazepin-2-one peptide turn mimics.

    Deaudelin, Philippe; Lubell, William D


    Sixteen pyrrolo[3,2- e][1,4]diazepin-2-ones 1 were synthesized in 4-5 steps and 5-48% overall yields from 4-oxoproline 8 by a route featuring a diastereoselective Pictet-Spengler reaction to close the seven-membered diazepinone ring. Crystallographic analysis of pyrrolo[3,2- e][1,4]diazepin-2-one 1b by X-ray diffraction demonstrated that the alpha-amino acid residue adopted dihedral angle geometry similar to an ideal gamma-turn, illustrating the potential for employing these novel heterocycles as peptide turn mimics.

  16. Highly diastereoselective zinc-catalyzed propargylation of tert-butanesulfinyl imines.

    Fandrick, Daniel R; Johnson, Courtney S; Fandrick, Keith R; Reeves, Jonathan T; Tan, Zhulin; Lee, Heewon; Song, Jinhua J; Yee, Nathan K; Senanayake, Chris H


    A zinc-catalyzed diastereoselective propargylation of t-butanesulfinyl imines is presented. The methodology provided both aliphatic and aryl homopropargylic amines in up to 98:2 and 99.8:0.2 dr, respectively. The utility of the homopropargylic amines was demonstrated by the application to the synthesis of a cis-substituted pyrido-indole through a diastereoselective Pictet-Spengler cyclization.

  17. Synergistic catalysis: highly diastereoselective benzoxazole addition to Morita-Baylis-Hillman carbonates.

    Ceban, Victor; Putaj, Piotr; Meazza, Marta; Pitak, Mateusz B; Coles, Simon J; Vesely, Jan; Rios, Ramon


    An expedited method has been developed for the diastereoselective synthesis of highly functionalized alkyl-azaarene systems with good yields and high diastereoselectivities (>15 : 1 dr). The methodology includes a synergistic catalysis event involving organometallic (10 mol% AgOAc) activation of an alkyl azaarene and Lewis base (10 mol% DABCO) activation of a Morita-Baylis-Hillman carbonate. The structure and relative configuration of a representative product were confirmed by X-ray analysis.

  18. In situ green synthesis of biocompatible ginseng capped gold nanoparticles with remarkable stability.

    Leonard, Kwati; Ahmmad, Bashir; Okamura, Hiroaki; Kurawaki, Junichi


    We report herein an unprecedented one-step green synthesis of gold nanoparticles (G-AuNps), using naturally occurring Korean red ginseng root (Panax ginseng C.A. Meyer) without any special reducing/capping agents. The AuNps generated through this ginseng-mediated process did not aggregate suggesting that the phytochemicals present in them serve as excellent coatings on the nanoparticles and thus, provide robust shielding from aggregations. The ginseng-generated AuNps exhibit remarkable in vitro stability in various buffers including: cysteine, histidine, saline, sodium chloride and a host of pH ranges. Furthermore, the phytochemical coatings on the G-AuNps rendered them nontoxic as demonstrated through detailed cytotoxicity assays using WST-8 counting kit, performed on normal cervical cells lines. The present study opens up a new possibility of conveniently synthesizing AuNps using natural products which will be useful in optoelectronic and biomedical applications.

  19. Bicyclic Pyrazolidinone Derivatives from Diastereoselective Catalytic [3 + 3]-Cycloaddition Reactions of Enoldiazoacetates with Azomethine Imines

    Qian, Yu; Zavalij, Peter J.; Hu, Wenhao; Doyle, Michael P.


    A highly regio- and diastereoselective synthesis of bicyclic pyrazolidinone derivatives by rhodium(II) acetate catalyzed [3+3]-annulation with enoldiazoacetates and azomethine imines has been achieved in high yield. A vinylogous reaction of the metal enol carbene with the azomethine imine initiates [3 + 3]-cycloaddition, whereas reaction at the carbene center effects N-N-cleavage of the azomethine imine. PMID:23477672

  20. Zn-catalyzed Enantio- and Diastereoselective Formal [4+2] Cycloaddition Involving Two Electron-Deficient Partners: Asymmetric Synthesis of Piperidines from 1-Azadienes and Nitroalkenes

    Chu, John C. K.; Dalton, Derek M.; Rovis, Tomislav


    We report a catalytic asymmetric synthesis of piperidines through [4+2] cycloaddition of 1-azadienes and nitroalkenes. The reaction uses earth abundant Zn as catalyst, and is highly diastereo- and regio-selective. A novel BOPA ligand (F-BOPA) confers high reactivity and enantioselectivity in the process. The presence of ortho substitution on the arenes adjacent to the bis(oxazolines) was found to be particularly impactful, due to limiting the undesired coordination of 1-azadiene to the Lewis ...

  1. β-Lactam synthon-interceded diastereoselective synthesis of functionalized octahydroindole-based molecular scaffolds and their in vitro cytotoxic evaluation.

    Singh, Pardeep; Raj, Raghu; Bhargava, Gaurav; Hendricks, Denver T; Handa, Sachin; Slaughter, Legrande M; Kumar, Vipan


    A convenient and unprecedented synthesis of functionally enriched octahydroindole-based scaffolds has been developed via inter- and intra-molecular amidolysis of C-3 functionalized β-lactams. The cytotoxic evaluation on oesophageal cancer cell line WHCO1 has revealed 7d as the most potent of the test compounds exhibiting an IC(50) value of 12.97 μM. The developed strategy further assumes significance as it entails the preparation of highly functionalized indoles without the aid of transition metal catalysis or pre-functionalization of substrates.

  2. Zn-catalyzed enantio- and diastereoselective formal [4 + 2] cycloaddition involving two electron-deficient partners: asymmetric synthesis of piperidines from 1-azadienes and nitro-alkenes.

    Chu, John C K; Dalton, Derek M; Rovis, Tomislav


    We report a catalytic asymmetric synthesis of piperidines through [4 + 2] cycloaddition of 1-azadienes and nitro-alkenes. The reaction uses earth abundant Zn as catalyst and is highly diastereo- and regioselective. A novel BOPA ligand (F-BOPA) confers high reactivity and enantioselectivity in the process. The presence of ortho substitution on the arenes adjacent to the bis(oxazolines) was found to be particularly impactful, due to limiting the undesired coordination of 1-azadiene to the Lewis acid and thus allowing the reaction to be carried out at lower temperature. A series of secondary kinetic isotope effect studies using a range of ligands implicates a stepwise mechanism for the transformation, involving an initial Michael-type addition of the imine to the nitro-alkene followed by a cyclization event. The stepwise mechanism obviates the electronic requirement inherent to a concerted mechanism, explaining the successful cycloaddition between two electron-deficient partners.

  3. Diastereoselective and enantioselective reduction of tetralin-1,4-dione


    Full Text Available BackgroundThe chemistry of tetralin-1,4-dione, the stable tautomer of 1,4-dihydroxynaphthalene, has not been explored previously. It is readily accessible and offers interesting opportunities for synthesis.ResultsThe title reactions were explored. L-Selectride reduced the diketone to give preferentially the cis-diol (d.r. 84 : 16. Red-Al gave preferentially the trans-diol (d.r. 13 : 87. NaBH4, LiAlH4, and BH3 gave lower diastereoselectivities (yields: 76–98%. Fractional crystallization allowed isolation of the cis-diol and the trans-diol (55% and 66% yield, respectively. Borane was used to cleanly give the mono-reduction product. Highly enantioselective CBS reductions afforded the trans-diol (72% yield, 99% ee and the mono-reduction product (81%, 95% ee.ConclusionDiastereoselective and enantioselective reductions of the unexplored tetralin-1,4-dione provides a very convenient entry into a number of synthetically highly attractive 1,4-tetralindiols and 4-hydroxy-1-tetralone.

  4. Remarkable Stereoelectronic Effect of the Methylenedioxy Phenyl System in the Total Synthesis of Cephalotaxine

    Hua YANG; Yong Qiang WANG; Wei DongZ. LI


    Methylenedioxyphenyl unit displays a significant stereoelectronic effect in some key transformations in the total synthesis of cephalotaxine. The ring-strain of methylenedioxy ring may account for some important facile ring-skeleton rearrangements.

  5. Synthesis of Isoiminosugars

    Hyldtoft, Lene; Godskesen, Michael Anders; Lundt, Inge


    A short synthesis of isoiminosugars have been developed. Bromolactones are diastereoselectively alkylated at C-2 followed by ring closure to the corresponding lactams. Reduction of these then gives isoiminosugars......A short synthesis of isoiminosugars have been developed. Bromolactones are diastereoselectively alkylated at C-2 followed by ring closure to the corresponding lactams. Reduction of these then gives isoiminosugars...

  6. Diastereoselective Addition of α-Metalated Sulfoxides to Imines Revisited: Mechanism, Computational Studies, and the Effect of External Chiral Ligands

    Pedersen, Brian; Rein, Tobias; Søtofte, Inger;


    Some new results on asymmetric synthesis via the addition of a-metalated methyl tolyl sulfoxides to imines are presented. Good diastereoselectivity (up to > 98% d.e. for product 3g) can be obtained under conditions of kinetic control (short reaction time, low temperature). The transition state (a...

  7. Diastereoselective Addition of α-Metalated Sulfoxides to Imines Revisited: Mechanism, Computational Studies, and the Effect of External Chiral Ligands

    Pedersen, Brian; Rein, Tobias; Søtofte, Inger


    six-membered "flat chair") was probed by quantum mechanical calculations, which underpinned the idea of using external chiral ligands to enhance the diastereoselectivity of otherwise moderately selective reactions. In this way, the diastereomeric ratio of the product 3a could be raised from (84 : 16......Some new results on asymmetric synthesis via the addition of a-metalated methyl tolyl sulfoxides to imines are presented. Good diastereoselectivity (up to > 98% d.e. for product 3g) can be obtained under conditions of kinetic control (short reaction time, low temperature). The transition state (a...

  8. Room temperature synthesis of microemulsion mediated rutile TiO{sub 2} nanoparticles showing remarkable photocatalytic activity

    Ovhal, Sheetal; Thakur, Pragati; Haram, Santosh [Pune Univ. (India). Dept. of Chemistry


    We report a simple low cost method at room temperature and normal pressure for the synthesis of mono-dispersed spherical rutile titania nanoparticles using the water in oil microemulsion process. The as-synthesized and calcined TiO{sub 2} nanoparticles were characterized by means of X-ray diffractometry, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis, Brunauer-Emmett-Teller surface area analysis, scanning electron microscopy and transmission electron microscopy. The effect of calcination temperature on the crystalline phase, particle size, specific surface area and surfactant concentration was studied in detail. As-synthesized rutile TiO{sub 2} nanoparticles showed remarkable photocatalytic activity for the degradation of methyl orange dye as a model pollutant. The reaction was found to follow first order kinetics. Chemical oxygen demand results show substantial degradation and mineralization of targeted dye. (orig.)

  9. Diastereoselective Pt catalyzed cycloisomerization of polyenes to polycycles.

    Geier, Michael J; Gagné, Michel R


    Application of a tridentate NHC containing pincer ligand to Pt catalyzed cascade cyclization reactions has allowed for the catalytic, diastereoselective cycloisomerization of biogenic alkene terminated substrates to the their polycyclic counterparts.

  10. Concluding remarks

    Patrick, W.C.


    This section contains the concluding remarks of the workshop on rock mechanics issues in repository design and performance assessment. Technical issues such as spatial variability of rock properties, rock mass strength, measurement of loads, evaluation of long-term seal performance, and integration of data into design were discussed. Programmatic issues such as development of a coherent and consistent design methodology and implementation of that methodology were also reiterated.

  11. Diastereoselective Diels–Alder Reactions of N-Sulfonyl-1-aza-1,3-butadienes With Optically Active Enol Ethers: An Asymmetric Variant of the 1-Azadiene Diels–Alder Reaction

    Clark, Ryan C.; Pfeiffer, Steven S.


    The first detailed study of a room temperature asymmetric Diels–Alder reaction of N-sulfonyl-1-aza-1,3-butadienes enlisting a series of nineteen enol ethers bearing chiral auxilaries is reported with many providing highly diastereoselective (endo and facial diastereoselection) reactions largely the result of an exquisitely organized [4 + 2] cycloaddition transition state. Three new, readily accessible, and previously unexplored auxilaries (18a, 19a and 37a) rationally emerged from the studies and provide remarkable selectivities (for 19a and 37a: 49:1 endo:exo and 48:1 facial selectivity) that promise to be useful in systems beyond those detailed. PMID:16492042

  12. Highly Diastereoselective Chelation-controlled Additions to α-Silyloxy Ketones

    Stanton, Gretchen R.; Koz, Gamze


    The polar Felkin-Anh, Cornforth, and Cram-chelation models predict that the addition of organometallic reagents to silyl–protected α–hydroxy ketones proceeds via a non-chelation pathway to give anti-diol addition products. This prediction has held true for the vast majority of additions reported in the literature and few methods for chelation-controlled additions of organometallic reagents to silyl–protected α–hydroxy ketones have been introduced. Herein, we present a general and highly diastereoselective method for the addition of dialkylzincs and (E)-di-, (E)-tri- and (Z)-disubstituted vinylzinc reagents to α-silyloxy ketones using alkyl zinc halide Lewis acids, RZnX, to give chelation-controlled products (dr ≥18:1). The compatibility of organozinc reagents with other functional groups makes this method potentially very useful in complex molecule synthesis. PMID:21534530

  13. Enhanced diastereoselectivity via confinement: diastereoselective photoisomerization of 2,3-diphenyl-1-benzoylcyclopropane derivatives within zeolites.

    Sivaguru, J; Sunoj, Raghavan B; Wada, Takehiko; Origane, Yumi; Inoue, Yoshihisa; Ramamurthy, V


    Photochemistry of optically pure trans-2,3-diphenyl-1-benzoylcyclopropane has been examined in isotropic solution and within zeolites. Results suggest that it isomerizes by cleavage of either the C1-C2 or C1-C3 bond. From the perspective of chiral induction, photoisomerization of cis-2,3-diphenyl-1-benzoylcyclopropane derivatives with chiral auxiliaries placed at the meta and para positions of the benzoyl group have been examined both in isotropic solution and within zeolites. Whereas in isotropic solution the chiral auxiliaries placed at the meta position exhibit very little influence during the conversion of triplet cis-2,3-diphenyl-1-benzoylcyclopropane derivatives, they have significant influence within zeolites. For example, alpha-methyl benzylamine placed at the meta position of the benzoyl group (via an amide bond) yields the trans isomer with a diastereoselectivity (de) of 71% within NaY zeolite, whereas in solution no de is obtained. The chiral induction process within zeolites depends on the nature of the alkali ion and on the presence of water. Results suggest that the chiral auxiliary is able to control the bond being cleaved (C1-C2 vs. C1-C3 bond) within a zeolite, but it is unable to do so in an isotropic solution.

  14. Electrochemical synthesis of multi-armed CuO nanoparticles and their remarkable bactericidal potential against waterborne bacteria

    Pandey, Pratibha, E-mail:; Merwyn, S.; Agarwal, G. S.; Tripathi, B. K.; Pant, S. C. [Defence Research and Development Establishment (India)


    Copper (II) oxide multi-armed nanoparticles composed of 500-1000 nm long radiating nanospicules with 100-200 nm width near the base and 50-100 nm width at the tapered ends and {approx}25 nm thickness were synthesized by electrochemical deposition in the presence of an oxidant followed by calcination at 150 Degree-Sign C. The nanoparticles were characterized using SEM/EDX for morphology and composition, Raman spectroscopy for compound identification, and broth culture method for antibacterial efficacy. The CuO nanoparticles have shown remarkable bactericidal efficacy against Gram-positive and -negative waterborne disease causing bacteria like Escherichia coli, Salmonella typhi, staphylococcus aureus and Bacillus subtilis. E. coli has been chosen as representative species for waterborne disease causing bacteria. In antibacterial tests 500 {mu}g/mL nano CuO killed 3 Multiplication-Sign 10{sup 8} CFU/mL E. coli bacteria within 4 h of exposure. Moreover, 8.3 Multiplication-Sign 10{sup 6} CFU/mL E. coli were killed by 100 and 10 {mu}g/mL nano CuO within 15 min and 4 h of exposure, respectively. Antibacterial activity of nano CuO has been found many-fold compared with commercial bulk CuO. The fate of nanoparticles after antibacterial test has also been studied. The synthesized CuO nanoparticles are expected to have potential antibacterial applications in water purification and in paints and coatings used on frequently touched surfaces and fabrics in hospital settings.

  15. Facile synthesis of bis(dichalcogenophosphinate)s and a remarkable [Li8(OH)6]2+ polyhedron.

    Davies, Robert P; Martinelli, M Giovanna; Patel, Laura; White, Andrew J P


    The synthesis and characterization of three lithium complexes of novel bis(dichalcogenophosphinate) ligands are reported: (PhP(S)(2)CH(2)CH(2)P(S)(2)Ph)Li(2)(THF)(4) (2), (PhP(Se)(2)CH(2)CH(2)P(Se)(2)Ph)Li(2)(THF)(4).(PhP(Se)(2)CH(2)CH(2)P(Se)(2)Ph)Li(2)(THF)(6) (3), and [PhP(Te)(2)CH(2)CH(2)P(Te)(2)Ph][Li(8)(OH)(6)(THF)(8)] (4). The synthetic route to these complexes proceeds via the insertion reaction of elemental chalcogens into the phosphorus-lithium bonds of 1,2-dilithio-1,2-di(phenylphosphine)ethylene (1). X-ray analysis of 2 revealed isobidentate coordination of the lithiums by the dithiophosphinate groups. In contrast, the diselenophosphinate groups in 3 coordinate the lithium centers in both isobidentate and monodentate modes, and the ditellurophosphinate groups in 4 form non-coordinate separate ion pairs. The countercation in 4 is shown to be a unique [Li(8)(OH)(6)](2+) rhombic dodecahedral polyhedron, putatively formed from the capping of a hexameric [Li(OH)](6) aggregate with lithium cations on its open faces.

  16. Brønsted acid-promoted azide–olefin [3 + 2] cycloadditions for the preparation of contiguous aminopolyols: The importance of disiloxane ring size to a diastereoselective, bidirectional approach to zwittermicin A

    Hubert Muchalski


    Full Text Available We report the first study of substrate-controlled diastereoselection in a double [3 + 2] dipolar cycloaddition of benzyl azide with α,β-unsaturated imides. Using a strong Brønsted acid (triflic acid to activate the electron deficient imide π-bond, high diastereoselection was observed provided that a 1,1,3,3-tetraisopropoxydisiloxanylidene group (TIPDS is used to restrict the conformation of the central 1,3-anti diol. This development provides a basis for a stereocontrolled approach to the aminopolyol core of (−-zwittermicin A using a bidirectional synthesis strategy.

  17. An Expedient Regio- and Diastereoselective Synthesis of Hybrid Frameworks with Embedded Spiro[9,10]dihydroanthracene [9,3′]-pyrrolidine and Spiro[oxindole-3,2′-pyrrolidine] Motifs via an Ionic Liquid-Mediated Multicomponent Reaction

    Natarajan Arumugam


    Full Text Available A series of hitherto unreported anthracene-embedded dispirooxindoles has been synthesized via a one-pot three-component 1,3-dipolar cycloaddition reaction of an azomethine ylide, generated in situ from the reaction of isatin and sarcosine to 10-benzylideneanthracen-9(10H-one as a dipolarophile in 1-butyl-3-methylimidazolium bromide([bmim]Br, an ionic liquid. This reaction proceeded regio- and diastereoselectively, in good to excellent yields.

  18. Short and efficient synthesis of fluorinated δ-lactams

    Cogswell, Thomas J.; Donald, Craig S.; Long, De-Liang; Marquez, Rodolfo


    The diastereoselective synthesis of fluorinated δ-lactams has been achieved through an efficient five step process. The route can tolerate a range of functionalities, and provides a quick route for the generation of new fluorinated medicinal building blocks.

  19. Remarkable biomimetic chemoselective aerobic oxidation of flavano-ellagitannins found in oak-aged wine.

    Petit, Emilie; Lefeuvre, Dorothée; Jacquet, Rémi; Pouységu, Laurent; Deffieux, Denis; Quideau, Stéphane


    Under the auspices of Bacchus! Acutissimins, natural flavano-ellagitannins, occur in oak-aged wine as a result of a diastereoselective condensation reaction of the flavan-3-ol catechin, a component of grapes, with the C-glucosidic ellagitannin vescalagin, found in oak. The acutissimins are further converted into natural mongolicains and analogues of camelliatannin G in a remarkably chemoselective fashion by simple aerobic oxidation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Total Synthesis of (-)-Conolutinine.

    Feng, Xiangyang; Jiang, Guangde; Xia, Zilei; Hu, Jiadong; Wan, Xiaolong; Gao, Jin-Ming; Lai, Yisheng; Xie, Weiqing


    The first enantioselective synthesis of (-)-conolutinine was achieved in 10 steps. The synthesis featured a catalytic asymmetric bromocyclization of tryptamine to forge the tricycle intermediate. Hydration of an alkene catalyzed by Co(acac)2 was also employed as a key step to diastereoselectively introduce the tertiary alcohol moiety. The absolute configuration of (-)-conolutinine was established to be (2S,5aS,8aS,13aR) based on this asymmetric total synthesis.

  1. Stereodivergent and Protecting-Group-Free Synthesis of the Helicascolide Family: A Rhodium-Catalyzed Atom-Economical Lactonization Strategy.

    Haydl, Alexander M; Berthold, Dino; Spreider, Pierre A; Breit, Bernhard


    Natural products of polyketide origin, in particular small-sized lactones often possess a very broad range of impressive biological activities. An efficient way to demonstrate the concise access to six-membered lactones was emphasized as part of a stereodivergent and protecting-group-free synthesis of all three representatives of the helicascolide family. This strategy features an atom-economical and highly diastereoselective rhodium-catalyzed "head-to-tail" lactonization by an intramolecular addition of ω-allenyl-substituted carboxylic acids to terminal allenes, including the selective construction of a new stereocenter in the newly formed core structures. The excellent selectivities with which the helicascolide precursors were obtained are remarkable, thus resulting in an expeditious and highly efficient natural product synthesis.

  2. Diastereoselective Michael Addition of (4'S)-Ethyl-3-(2',2'-Dimethyl-1',3'-dioxolan-4'-yl) acrylate with Furyl Lithium


    Michael addition of the chiral a,b-unsaturated ester 2 with furyl lithium proceeded in syn manner with excellent diastereoselectivity.The diastereoselectivity was not affected by the configuration of the double bond in 2.

  3. Inverting the diastereoselectivity of the mukaiyama-michael addition with graphite-based catalysts

    Acocella, Maria Rosaria


    Here, we show that graphite-based catalysts, mainly graphite oxide (GO) and exfoliated GO, are effective recyclable catalysts for a relevant stereoselective Mukaiyama-Michael addition, outperforming currently available catalysts. Moreover, the graphite-based catalysts described here invert the diastereoselectivity relative to that observed with known catalysts, with the unprecedented large prevalence of the anti diastereoisomer. This inverted diastereoselectivity is increased when the catalyst concentration is reduced and after catalyst recycling. Density functional theory calculations suggest that the selectivity is determined by two types of supramolecular interactions operating between the catalyst and the substrates at the diastereoselectivity- determining transition state, specifically, the π-stacking of b-nitrostyrene with graphite and the van der Waals interaction between the SiMe3 group of the silyl ether and the graphite. © 2013 American Chemical Society.

  4. Switchable Diastereoselectivity in the Fluoride Promoted Vinylogous Mukaiyama-Michael Reaction of 2-Trimethylsilyloxyfuran Catalyzed by Crown Ethers

    Della Sala, Giorgio


    The fluoride promoted vinylogous Mukaiyama-Michael reaction (VMMR) of 2-trimethylsilyloxyfuran with diverse α,β-unsaturated ketones is described. The TBAF catalyzed VMMR afforded high anti-diastereoselectivity irrespective of the solvents used. The KF/crown ethers catalytic systems proved to be highly efficient in terms of yields and resulted in a highly diastereoselective unprecedented solvent/catalyst switchable reaction. Anti-adducts were obtained as single diastereomers or with excellent diastereoselectivities when benzo-15-crown-5 in CH2Cl2 was employed. On the other hand, high syn-diastereoselectivities (from 76:24 to 96:4) were achieved by employing dicyclohexane-18-crown-6 in toluene. Based on DFT calculations, the catalysts/solvents-dependent switchable diastereoselectivities are proposed to be the result of loose or tight cation-dienolate ion pairs.

  5. A Synthesis of the Tricyclic Core Structure of FR901483 Featuring an Ugi Four-Component Coupling and a Remarkably Selective Elimination Reaction1

    Seike, Hirofumi


    Three key reactions, an efficient Ugi four-component coupling, a regiospecific, base-mediated elimination reaction, and an intramolecular nitrone/alkene [3+2] cycloaddition, were used to achieve an effective synthesis of the tricyclic molecular framework of the immunosuppressant FR901483. The outcome of a control experiment supports the idea that an internal deprotonation by an alkoxide ion is the origin of the site selectivity observed in the base-induced elimination of hydroxy mesylate 17. PMID:22114366

  6. A Synthesis of the Tricyclic Core Structure of FR901483 Featuring an Ugi Four-Component Coupling and a Remarkably Selective Elimination Reaction.

    Seike, Hirofumi; Sorensen, Erik J


    Three key reactions, an efficient Ugi four-component coupling, a regiospecific, base-mediated elimination reaction, and an intramolecular nitrone/alkene [3+2] cycloaddition, were used to achieve an effective synthesis of the tricyclic molecular framework of the immunosuppressant FR901483. The outcome of a control experiment supports the idea that an internal deprotonation by an alkoxide ion is the origin of the site selectivity observed in the base-induced elimination of hydroxy mesylate 17.

  7. Facile combustion synthesis of novel CaZrO3:Eu3+, Gd3+ red phosphor and remarkably enhanced photoluminescence by Gd3+ doping

    Qingqing Du; Guangjun Zhou; Shuo Zhang; Xiao Jia; Haifeng Zhou; Zhongsen Yang


    A facile sol–gel combustion route was reported for the direct preparation of CaZrO3:Eu3+ and CaZrO3:Eu3+, Gd3+. The obtained deposits were characterized by XRD, TGA-DSC, SEM, EDS, PL measurements and microscope fluorescence. When the Gd3+ ions were introduced in this compound, the emissions of CaZrO3:Eu3+ were remarkably enhanced. The emission spectrum of CaZrO3:Eu3+, Gd3+ nanocrystals exhibited a red shift compared with CaZrO3:Eu3+ samples. A new mechanism of the improved photoluminescent properties of Eu3+ by Gd3+ was investigated. The optimized phosphor CaZrO3:5%Eu3+, 2%Gd3+ could be considered an efficient red-emitting component for white lighting devices excited in the near-ultraviolet region.

  8. Remarkable rate acceleration of SmI3-mediated iodination of acetates of Baylis-Hillman adducts in ionic liquid: facile synthesis of (Z)-allyl iodides


    Stereoselective transformation of Baylis-Hillman acetates 1 into corresponding (Z)-allyl iodides 2 has been achieved by treatment of 1 with samarium triiodide in THF. Remarkable rate acceleration of samarium triiodide-mediated iodination of 1 was found when ionic liquid 1-n-butyl-3-methyl-imidazolium tetrafluroborate ([bmim]BF4) was used as reaction media in stead of THF. This novel approach proceeds readily at 50 ℃ within a few minutes to afford (Z)-allyl iodides 2 in excellent yields. A mechanism involving stereoselective iodination of the acetates of Baylis-Hillman adducts by samarium triiodide is described, in which a six-membered ring transition state played a key role in the stereoselective formation of 2.

  9. Synthesis and Characterization of Novel Copper(II 2D Coordination Polymers from a Fluorinated Flexible Ligand with Remarkable Clathration Ability

    Kayoko Kasai


    Full Text Available Two-dimensional (2D grid coordination polymers were prepared by the reaction of 1,4-bis(4-pyridylmethyltetrafluorobenzene (bpf with Cu(NO32 in the presence of aromatic compounds. Crystal structures of {[Cu(bpf2(NO32]·(biphenyl2}n (1, {[Cu(bpf2(NO32]·(m-C6H4(OMe22}n (2, {[Cu(bpf2(NO32]·PhtBu}n (3 and {[Cu(bpf2(NO3(H2O]NO3·(bpf0.5}n (4 were determined. The grid networks were held together by C–H···O and C–H···F hydrogen bonds via the NO3− anions and the tetrafluorophenylene rings of bpf, respectively. Biphenyl, m-dimethoxybenzene, t-butylbenzene, and bpf molecules were clathrated in cyclic cavities of the grid networks through arene-perfluoroarene interactions. These coordination networks have remarkable clathration ability for aromatic compounds.

  10. Newly developed stepwise electroless deposition enables a remarkably facile synthesis of highly active and stable amorphous Pd nanoparticle electrocatalysts for oxygen reduction reaction.

    Poon, Kee Chun; Tan, Desmond C L; Vo, Thang D T; Khezri, Bahareh; Su, Haibin; Webster, Richard D; Sato, Hirotaka


    This paper reports on highly active and stable amorphous Pd nanoparticle electrocatalysts for the oxygen reduction reaction. The amorphous catalysts were synthesized by a remarkably facile and quick electroless deposition process newly developed in this study (process time <5 min). An electrode substrate (glassy carbon, carbon cloth) was sequentially dipped for 10 s into two separate solutions of a reducing agent (sodium hypophosphite (NaH2PO2)) and Pd ions to deposit amorphous Pd nanoparticles containing phosphorus (Pd-P). By repeating the deposition cycles, the specific and mass activities of the Pd nanoparticles can be actively tuned. Owing to the nanoscale amorphous nature, the obtained Pd-P nanoparticle electrocatalysts exhibited superior specific and mass activities compared with crystalline Pd nanoparticles synthesized by another reducing agent (N2H4) and commercial Pt-loaded carbon (Pt/C) and Pd-loaded carbon (Pd/C). The specific and mass activities of the amorphous Pd-P nanoparticles were over 4.5 times and 2.6 times higher than previously reported values of Pd and Pt catalysts.

  11. Diastereoselective Ugi reaction of chiral 1,3-aminoalcohols derived from an organocatalytic Mannich reaction

    Samantha Caputo


    Full Text Available Enantiomerically pure β-aminoalcohols, produced through an organocatalytic Mannich reaction, were subjected to an Ugi multicomponent reaction under classical or Lewis acid-promoted conditions with diastereoselectivities ranging from moderate to good. This approach represents a step-economical path to enantiomerically pure, polyfunctionalized peptidomimetics endowed with three stereogenic centers, allowing the introduction of five diversity inputs.

  12. Computational investigations on the general reaction profile and diastereoselectivity in sulfur ylide promoted aziridination.

    Janardanan, Deepa; Sunoj, Raghavan B


    Mechanism and diastereoselectivity of sulfur ylide promoted aziridination reactions were studied by density functional theory with inclusion of solvent effects through the continuum solvation model. The general reaction pathway was modeled for the addition of substituted sulfur ylides (Me(2)S(+)CH(-)R) to an aldimine ((E)-methyl ethylidenecarbamate, MeHC=NCO(2)Me). The nature of the substituents on the ylidic carbon atom substantially affects the reaction profile. The stabilized (R=COMe) and semistabilized (R=Ph) ylides follow a cisoid addition mode leading to trans aziridines via anti betaine intermediates. The simplest model ylide (unstabilized, R=H) underwent cisoid addition in a similar fashion. In the case of stabilized ylides product diastereoselectivity is controlled by the barriers of the elimination step leading to the 2,3-trans aziridine, whereas it is decided in the addition step in the case of semistabilized ylides. The importance of steric and electronic factors in diastereoselective addition (2 and 5) and elimination (5) transition states was established. Comparison of results obtained with the gas-phase optimized geometries and with the fully optimized solvent-phase geometries reveals that the inclusion of solvent effects does not bring about any dramatic changes in the reaction profiles for all three kinds of ylides. In particular, diastereoselectivity for both kinds of ylides was found to be nearly the same in both these approaches.

  13. Diastereoselective Hydrogenation and Kinetic Resolution of Imines Using Rhodium/Diphosphine Catalyzed Hydrogenation.

    Lensink, Cornelis; Vries, Johannes G. de


    Kinetic resolution of racemic α-methylbenzyl amine can be achieved with 98% ee. of the remaining amine at 70% conversion using the Rhodium/2S,4S-BDPP catalyzed asymmetric hydrogenation of imines. The same catalyst will hydrogenate optically pure α-methylbenzyl amines with a diastereoselectivity of u

  14. Total synthesis of the potent microtubule-stabilizing agent (+)-discodermolide.

    Harried, Scott S; Lee, Christopher P; Yang, Ge; Lee, Tony I H; Myles, David C


    The total synthesis of the potent microtubule-stabilizing, antimitotic agent (+)-discodermolide is described. The convergent synthetic strategy takes advantage of the diastereoselective alkylation of a ketone enolate to establish the key C15-C16 bond. The synthesis is amenable to preparation of gram-scale quantities of (+)-discodermolide and analogues.

  15. The remarkable Dr Robertson

    Hammarton, Tansy C.


    Muriel Robertson (1883–1973) was a pioneering protozoologist who made a staggering number of important contributions to the fields of parasitology, bacteriology and immunology during her career, which spanned nearly 60 years. These contributions were all the more remarkable given the scientific and social times in which she worked. While Muriel is perhaps best known for her work on the life cycle and transmission of the African trypanosome, Trypanosoma brucei, which she carried out in Uganda ...

  16. A global and local desymmetrization approach to the synthesis of steroidal alkaloids: stereocontrolled total synthesis of paspaline.

    Sharpe, Robert J; Johnson, Jeffrey S


    A stereocontrolled total synthesis of the indole diterpenoid natural product paspaline is described. Key steps include a highly diastereoselective enzymatic desymmetrization, substrate-directed epoxidation, Ireland-Claisen rearrangement, and diastereotopic group selective C-H acetoxylation to assemble the target with excellent stereofidelity. The route and results described herein outline complementary conceptual disconnections in the arena of steroid natural product synthesis.

  17. A Global and Local Desymmetrization Approach to the Synthesis of Steroidal Alkaloids: Stereocontrolled Total Synthesis of Paspaline


    A stereocontrolled total synthesis of the indole diterpenoid natural product paspaline is described. Key steps include a highly diastereoselective enzymatic desymmetrization, substrate-directed epoxidation, Ireland-Claisen rearrangement, and diastereotopic group selective C–H acetoxylation to assemble the target with excellent stereofidelity. The route and results described herein outline complementary conceptual disconnections in the arena of steroid natural product synthesis.

  18. A diastereoselective cyclic imine cycloaddition strategy to access polyhydroxylated indolizidine skeleton: concise syntheses of (+)-/(-)-lentiginosines and (-)-2-epi-steviamine.

    Shao, Jia; Yang, Jin-Song


    We describe in this paper the development of a novel diastereoselective cyclic imine cycloaddition strategy to access the polyhydroxylated indolizidine skeleton and its application in the concise syntheses of (+)-/(-)-lentiginosines and (-)-2-epi-steviamine.

  19. Total synthesis of (+/-)-cytisine.

    O'Neill, B T; Yohannes, D; Bundesmann, M W; Arnold, E P


    [reaction:see text] The nicotine partial agonist cytisine was prepared in five steps featuring an "in situ" Stille or Suzuki biaryl pyridine coupling. Differentiation of the pyridyl rings was accomplished via selective benzylation and then reduction of a pyridinium ring. The penultimate diazabicyclo[3.3.1]nonane intermediate was obtained with high diastereoselectivity. A similar sequence has been employed for the synthesis of novel derivative 9-methoxycytisine.

  20. Total synthesis of aeruginosin 98B.

    Trost, Barry M; Kaneko, Toshiyuki; Andersen, Neil G; Tappertzhofen, Christoph; Fahr, Bruce


    The first total synthesis of aeruginosin 98B was accomplished. The key step is a highly diastereoselective Pd-catalyzed intramolecular asymmetric allylic alkylation reaction of a diastereomeric mixture of allylic carbonates that is enabled by the use of racemic phosphine ligand L1.

  1. Seven remarkable days

    This has been a truly remarkable seven days for CERN. Things have moved so fast that it has sometimes been hard to separate fact from fiction – all the more so since facts have often seemed too good to be true. It’s been a week of many firsts. Monday was the first time we’ve had two captured beams in the LHC. It’s the first time the LHC has functioned as a particle accelerator, boosting particles to the highest beam energy so far achieved at CERN. And it’s been a week in which we’ve seen the highest energy proton-proton collisions ever produced at CERN: our last hadron collider, the SPS was a proton-antiproton collider, a technically simpler machine than the LHC. This week’s successes are all the more remarkable precisely because of the complexity of the LHC. Unlike the SPS collider, it is two accelerators not one, making the job of commissioning nearly twice as difficult. I’d like to express my heartfelt thanks and congra...

  2. Enantioselective Synthesis of Protease Inhibitors and AntiHIV Agents

    WANG Zhe


    @@ Part 1: A highly enantio-and diastereoselective Ireland-Claisen rearrangement of chiral C3(acyloxy)-vinyl silanes for the synthesis of anti-disubstituted succinic acid, an important intermediate for matrix metalloprotease inhibitors, has been developed (enantio-and anti/syn selectivities up to 95% and 38/1). The diastereoselectivity of this reaction was found to be sensitive to remote hydroxyl protecting groups, for example, with-OMOM group, the anti/syn ratio was 19/1, while with-OTBDMS, the ratio was 38/1. The resultant Ireland-Claisen rearrangement product was applied to the synthesis of macrocyclic MMP inhibitors, such as SL 422.

  3. A Short Synthesis of (+)-Cyclophellitol

    Hansen, Flemming Gundorph; Bundgaard, Eva; Madsen, Robert


    A new synthesis of (+)-cyclophellitol, a potent b-glucosidase inhibitor, has been completed in nine steps from D-xylose. The key transformations involve a zinc-mediated fragmentation of benzyl-protected methyl 5-deoxy-5-iodo-xylofuranoside followed by a highly diastereoselective indium-mediated c......A new synthesis of (+)-cyclophellitol, a potent b-glucosidase inhibitor, has been completed in nine steps from D-xylose. The key transformations involve a zinc-mediated fragmentation of benzyl-protected methyl 5-deoxy-5-iodo-xylofuranoside followed by a highly diastereoselective indium......-mediated coupling with ethyl 4-bromocrotonate. Subsequent ring-closing olefin metathesis, ester reduction, olefin epoxidation, and deprotection then afford the natural product. This constitutes the shortest synthesis of (+)-cyclophellitol reported to date....

  4. Diastereoselective anodic hetero- and homo-coupling of menthol-, 8-methylmenthol- and 8-phenylmenthol-2-alkylmalonates

    Matthias C. Letzel


    Full Text Available Diastereoselective radical coupling was achieved with chiral auxiliaries. The radicals were generated by anodic decarboxylation of five malonic acid derivatives. These were prepared from benzyl malonates and four menthol auxiliaries. Coelectrolyses with 3,3-dimethylbutanoic acid in methanol at platinum electrodes in an undivided cell afforded hetero-coupling products in 22–69% yield with a diastereoselectivity ranging from 5 to 65% de. Electrolyses without a coacid led to diastereomeric homo-coupling products in 21–50% yield with ratios of diastereomers being 1.17:2.00:0.81 to 7.03:2.00. The stereochemistry of the new stereogenic centers was confirmed by X-ray structure analysis and 13C NMR data.

  5. Diastereoselective B(C6F5)3-Catalyzed Reductive Carbocyclization of Unsaturated Carbohydrates.

    Bender, Trandon A; Dabrowski, Jennifer A; Zhong, Hongyu; Gagné, Michel R


    A B(C6F5)3-catalyzed method for the selective conversion of unsaturated carbohydrates to cyclopentanes and cyclopropanes is disclosed. Catalyst activation of tertiary silanes generates the ion pair [(C6F5)3B-H][ROSi2] whose components synergistically activate C-O bonds for diastereoselective C-C bond formation. Sila-THF cations are invoked as key intermediates facilitating carbocyclizations. Complex chiral synthons are thereby obtained in a single pot.

  6. Solvent-dependent diastereoselectivities in reductions of beta-hydroxyketones by SmI2.

    Chopade, Pramod R; Davis, Todd A; Prasad, Edamana; Flowers, Robert A


    The reductions of a series of beta-hydroxyketones by SmI(2) were examined in THF, DME, and CH(3)CN using methanol as a proton source. Reductions in THF and DME typically lead to the syn diastereomer with DME providing higher diastereoselectivities. Reductions in CH(3)CN provided the anti diastereomer predominantly. This study reveals that solvation plays an important role in substrate reduction by SmI(2). [reaction: see text

  7. Enantio- and diastereoselectivities in chiral sulfur ylide promoted asymmetric aziridination reactions.

    Janardanan, Deepa; Sunoj, Raghavan B


    Density functional theory investigation on the factors controlling enantio- and diastereoselection in asymmetric aziridination reaction by the addition of chiral bicyclic sulfur ylides to substituted aldimines is presented. High levels of enantioselection are predicted toward the formation of (2S,3S)-cis and (2R,3S)-trans aziridines by the addition of stabilized ylide (R = COMe) respectively to SO2Me and CO2Me protected aldimines. Similarly, high %ee is predicted for the formation of (2S,3R)-cis aziridines from semistabilized (R = Ph) ylide. Moderate to high levels of diastereoselectivity is noticed as well. The present study highlights that a correct prediction on extent of enantioselection requires the knowledge of the activation barriers for elementary steps beyond the initial addition step. In the case of stabilized ylides the ring-closure (or elimination of sulfur compound) is found to be crucial in controlling enantio- and diastereoselection. A cumulative effect of electronic as well as other weak interactions is identified as factors contributing to the relative energies of transition states leading to enantio- and diastereomeric products for the stabilized ylide addition to aldimines. On the contrary, steric control appears quite dominant with semistabilized ylide addition. With the smallest substituent on ylide (R = Me), high enantioselectivity is predicted for the formation of (2R,3R)-trans aziridines although the %de in this case is found to be very low.

  8. Density functional theory investigations on sulfur ylide promoted cyclopropanation reactions: insights on mechanism and diastereoselection issues.

    Janardanan, Deepa; Sunoj, Raghavan B


    The mechanism and diastereoselectivity of synthetically useful sulfur ylide promoted cyclopropanation reactions have been studied using the density functional theory method. Addition of different substituted ylides (Me2S+CH-R) to enone ((E)-pent-3-en-2-one, MeHC=CH-COMe) has been investigated. The nature of the substituent on the ylidic carbon brings about subtle changes in the reaction profile. The stabilized (R=COMe) and semistabilized (R=Ph) ylides follow a cisoid addition mode, leading to 1,2-trans and 1,2-cis cyclopropanes, respectively, via syn and anti betaine intermediates. The simplest and highly reactive model ylide (R=H) prefers a transoid addition mode. Diastereoselectivity is controlled by the barrier for cisoid-transoid rotation in the case of stabilized ylides, whereas the initial electrophilic addition is found to be the diastereoselectivity-determining step for semistabilized ylides. High selectivity toward trans cyclopropanes with stabilized ylides are predicted on the basis of the relative activation energies of diastereomeric torsional transition states. The energy differences between these transition states could be rationalized with the help of weak intramolecular as well as other stereoelectronic interactions.


    José Claudinei Lombardi


    Full Text Available Based on the joint context of the theory of crises and the resultant theory of revolutions of Marx and Engels for the analysis of the genesis, development and death of Capitalism, a summary of the historical confronts from which relations of capital have been hegemonic in the XX and XXI centuries is presented. Within this same context, a synthesis of the debates on the structural crisis of Capitalism in the past years is made with an emphasis on its relevance and seriousness in history. It is emphasized that communism is not an idea to be implemented but a reality to be constructed by real men in struggles, conquests and defeats. The revolution of a way of production is not made by itself or by decree, but it is in fact the product of organized men. It is claimed that the maturing of a struggle may lead to the formation of a wide front to articulate anti-capitalist and revolutionary forces. It is observed the need for a tactic and strategic organization to overcome the logics of the Capital and the role each educationalist must play to expand and deepen the debate.

  10. Iridium-Catalyzed Dynamic Kinetic Isomerization: Expedient Synthesis of Carbohydrates from Achmatowicz Rearrangement Products.

    Wang, Hao-Yuan; Yang, Ka; Bennett, Scott R; Guo, Sheng-rong; Tang, Weiping


    A highly stereoselective dynamic kinetic isomerization of Achmatowicz rearrangement products was discovered. This new internal redox isomerization provided ready access to key intermediates for the enantio- and diastereoselective synthesis of a series of naturally occurring sugars. The nature of the de novo synthesis also enables the preparation of both enantiomers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Stereoselective Synthesis of (+)-Boronolide

    HU,Shou-Gang; HU,Tai-Shan; WU,Yu-Lin


    @@ (+)-Boronolide (1) and its deacetylated products have attracted much attention of synthetic chemists due to their diverse biological properties as well as their structural complexities.[1] Many of these reported synthesis involved dehydrogenation of δ-lactone by using benzeneseleninic anhydride or ring-closing olefin metathesis (RCM) to introduce the requisite α,β-unsaturated δ-lactone in boronolide. Here, we report the synthesis of boronolide with diastereoselective propargylation of α-hydroxy aldehyde as the key step and D-gluconolactone as the starting material.

  12. Iron-Catalyzed Synthesis of Sulfur-Containing Heterocycles.

    Bosset, Cyril; Lefebvre, Gauthier; Angibaud, Patrick; Stansfield, Ian; Meerpoel, Lieven; Berthelot, Didier; Guérinot, Amandine; Cossy, Janine


    An iron-catalyzed synthesis of sulfur- and sulfone-containing heterocycles is reported. The method is based on the cyclization of readily available substrates and proceeded with high efficiency and diastereoselectivity. A variety of sulfur-containing heterocycles bearing moieties suitable for subsequent functionalization are prepared. Illustrative examples of such postcyclization modifications are also presented.

  13. Me2Zn-Mediated Catalytic Enantio- and Diastereoselective Addition of TosMIC to Ketones.

    Keeri, Abdul Raheem; Gualandi, Andrea; Mazzanti, Andrea; Lewinski, Janusz; Cozzi, Pier Giorgio


    The first catalytic asymmetric addition of TosMIC to unactivated ketones is presented. A combination of Me2Zn and aminoalcohol catalyst promoted the aldol addition/cyclization reaction to render oxazolines possessing a fully substituted stereocenter with excellent yields (up to 92%), high enantioselectivities (up to 96%), and complete diastereoselectivity. The chiral oxazolines were then used to give, after a straightforward acid hydrolysis, enantioenriched building blocks bearing tertiary alcohol motifs such as hydroxylaldehydes, hydroxylacids, and hydroxylesters without racemization. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Complexes of 5,5'-aminoacido-substituted 2,2'-bipyridyl ligands: control of diastereoselectivity with a pH switch and a chloride-responsive combinatorial library.

    Telfer, Shane G; Yang, Xiao-Juan; Williams, Alan F


    The synthesis and coordination chemistry of a new chiral ligand, 2,2'-bipyridine substituted at the 5 and 5' positions by N-methyl-L-valine methyl ester (5), is presented. The ligand readily forms complexes [M(5)3]2+ where M = Co(II) and Fe(II) in CH3CN, and the complexation reaction is slightly diastereoselective (d.e. =ca. 20%) in favour of the Delta diastereomer. The addition of six equivalents of HCl to these complexes [M(II)(5)3]2+ leads to formation of Delta-[M(II)(5H2)3]8+ with a d.e. of 100%. This high diastereoselectivity can be reversed by the addition of base i.e. the diastereoselectivity can be controlled by the pH. Delta-[Fe(5H2)3]8+ was found to bind chloride ions in CD3OD-CD3CN (6:1) with a binding constant of 260 M(-1). [Co(II)(5)3]2+ can be oxidised to Delta-[Co(III)(5H2)3]9+. Formation constants for both [Co(II)(5)3]2+ and [Co(II)(5H2)3]8+ in acetonitrile were obtained by spectrophotometric titrations. In the former case, the stability constant, log beta3 = 19.5(8), is very similar to that measured for [Co(II)(bipy)3]2+ (log beta3 = 19.3(7)) but this drops significantly when the amine groups of are protonated (log beta3 = 16.5(2)). A dynamic combinatorial library was prepared by mixing three equivalents of, three equivalents of bipy, and two equivalents of Co(II) in CD3CN. The presence of all possible Delta- and Lambda-[Co(II)(5)x(bipy)(3-x)]2+ complexes was inferred from 1H NMR and ES-MS spectra. Addition of protons to this library reduced the number of components by inducing diastereoselectivity, and presence of chloride further simplified the 1H NMR spectrum, indicating that [Cl2 ligand Delta-[Co(II)(5H2)3

  15. N-Heterocyclic-Carbene-Catalysed Diastereoselective Vinylogous Mukaiyama/Michael Reaction of 2-(Trimethylsilyloxy)furan and Enones

    Wang, Ying


    N-heterocyclic carbenes have been utilised as highly efficient nucleophilic organocatalysts to mediate vinylogous Mukaiyama/Michael reactions of 2-(trimethylsilyloxy)furan with enones to afford γ-substituted butenolides in 44-99% yield with 3:1-32:1 diastereoselectivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Highly enantio- and diastereoselective synthesis of β-methyl-γ- monofluoromethyl-substituted alcohols

    Yang, Wenguo


    Enanatiopure β-methyl-γ-monofluoromethyl alcohols were prepared from the allylic alkylation between fluorobis(phenylsulfonyl)methane with Morita-Baylis-Hillman carbonates. The reaction was catalyzed by using the Cinchona alkaloid derivative, (DHQD)2AQN. The origin of the stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed stereoselectivity. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Highly Efficient Diastereoselective Synthesis of Tetrahydro-isoquinoline-3- carboxylate Ester Analogs from L-DOPA

    WANG Ye; LIU Zhan-Zhu; CHEN Shi-Zhi; LIANG Xiao-Tian


    @@ Tetrahydroisoquinoline-3-carboxylate esters are an important motif of naturally occurring bioactive alkaloids and pharmacophores. They are generally regarded as neurotoxic compounds and are putatively involved in a variety of pathologic conditions of central nervous system, including alcoholism, phenylketonuria, and neurodegenerative disorders such as Parkinson's disease.

  18. Asymmetric synthesis of (-)-adaline.

    Itoh, Toshimasa; Yamazaki, Naoki; Kibayashi, Chihiro


    [reaction: see text] An enantioselective total synthesis of (-)-adaline has been achieved starting from a chiral 6,6-disubstituted piperidone derivative previously prepared by diastereoselective allylation of a chiral tricyclic N-acyl-N,O-acetal. The key steps include lithium ion-activated SN2-type alkynylation of the tricyclic N,O-acetal leading to exclusive formation of the (6S)-ethynylpiperidine and ring-closing olefin metathesis of the (2R,6S)-cis-2,6-dialkenylpiperidine for constructing the bridged azabicyclononane.

  19. Nazarov cyclization initiated by peracid oxidation: the total synthesis of (+/-)-rocaglamide.

    Malona, John A; Cariou, Kevin; Frontier, Alison J


    The total syntheses of aglafolin, rocagloic acid, and rocaglamide using Nazarov cyclization are described. Generation of the necessary oxyallyl cation intermediate was accomplished via peracid oxidation of an allenol ether to generate an unusual oxycarbenium ion species that undergoes cyclization. The synthesis is efficient, highly diastereoselective, and strategically distinct from previous syntheses of rocaglamide.

  20. Asymmetric Synthesis of the C(17)-C(28)Subunit of Didemnaketal B

    LI,Xue-Qiang; HE,Qin; TU,Yong-Qiang; ZHANG,Fu-Min; ZHANG,Shu-yu


    The stereocontrolled synthesis of the C(17)-C(28) fragment 3 of didemnaketal B was accomplished in 21 steps from the natural (R)-(+)-pulegone and (S)-(-)-citronellal. The key steps involved diastereoselective construction of two chiral carbon centers through the intramolecular chiral induction and uncommon Julia olefination of ketone forming the E-trisubstituted C(22)-C(23) double bound.

  1. Asymmetric Total Syntheses of (-)-α-Lycorane, (-)-Zephyranthine and Formal Synthesis of (+)-Clivonine

    Chen, Yong-Jian; Cai, Sen-Lin; Wang, Chuan-Chuan


    We report the successful achievement of an asymmetric route to (-)-α-lycorane and (-)-zephyranthine as well as a formal total synthesis of (+)-clivonine. A pivotal intermediate, which serves as a potent precursor for the divergent syntheses of these natural products, was accessed by a diastereose...... by a diastereoselective Pd-catalyzed cinnamylation of an N-tert-butanesulfinyl imine....

  2. A concise enantioselective synthesis of the guaiane sesquiterpene (−-oxyphyllol

    Martin Zahel


    Full Text Available (−-Oxyphyllol was prepared in only 4 steps from an epoxy enone that already served as an intermediate for the total synthesis of the anticancer guaiane (−-englerin A. A regio- and diastereoselective Co(II-catalyzed hydration of the olefin and a transannular epoxide opening were used as the key reactions.

  3. Stereoselection in Intramolecular Diels-Alder Reactions of 2-Cyano-1-azadienes: Indolizidine and Quinolizidine Synthesis.

    Tay, Gidget C; Sizemore, Nicholas; Rychnovsky, Scott D


    Progress toward understanding the scope and diastereoselectivity of intramolecular Diels-Alder reactions using 2-cyano-1-azadienes is described herein. The resulting cyanoenamine products are underutilized intermediates in organic synthesis. Assembly of the Diels-Alder precursors was achieved using an improved imine condensation/oxidative cyanation protocol. By this method, several highly substituted indolizidine and quinolizidine architectures were constructed. Quantum mechanical DFT calculations at the B3LYP/6-31+G(d) level of theory were performed for these cyclizations and provide insights into the origins of the observed diastereoselectivities.

  4. Remarks on the clump theory

    Krommes, J.A.


    Further details are provided of a soon-to-be published dialog (Phys. Fluids 29 (July, 1986)) which discussed the role of the small scales in fluid clump theory. It is argued that the approximation of the clump lifetime which is compatible with exponentially rapid separation of adjacent orbits is inappropriate for the description of the dynamically important large scales. Various other remarks are made relating to the analytic treatment of strong drift-wave-like turbulence.

  5. A 11-Steps Total Synthesis of Magellanine through a Gold(I)-Catalyzed Dehydro Diels-Alder Reaction.

    McGee, Philippe; Bétournay, Geneviève; Barabé, Francis; Barriault, Louis


    We have developed an innovative strategy for the formation of angular carbocycles via a gold(I)-catalyzed dehydro Diels-Alder reaction. This transformation provides rapid access to a variety of complex angular cores in excellent diastereoselectivities and high yields. The usefulness of this Au(I) -catalyzed cycloaddition was further demonstrated by accomplishing a 11-steps total synthesis of (±)-magellanine.

  6. One-pot synthesis of substituted di-hydrofurans from Lewis base-catalyzed three-component condensation.

    Zhong, Cheng; Liao, Tao; Tuguldur, Odbadrakh; Shi, Xiaodong


    A one-pot synthesis of substituted dihydrofurans was developed through a Lewis base-catalyzed three-component cascade condensation between nitroalkenes, aldehydes, and 1,3-dicarbonyl compounds. The desired cyclization products were prepared with a large substrate scope (22 examples) and excellent diastereoselectivity (only trans isomers) in good to excellent yields (up to 95%).

  7. Phosphine-catalyzed [4 + 1] annulation between α,β-unsaturated imines and allylic carbonates: synthesis of 2-pyrrolines.

    Tian, Junjun; Zhou, Rong; Sun, Haiyun; Song, Haibin; He, Zhengjie


    In this report, a phosphine-catalyzed [4 + 1] annulation between α,β-unsaturated imines and allylic carbonates is described. This reaction represents the first realization of catalytic [4 + 1] cyclization of 1,3-azadienes with in situ formed phosphorus ylides, which provides highly efficient and diastereoselective synthesis of 2-pyrrolines.

  8. N,N-Diisopropyl-N-phosphonyl Imines Lead to Efficient Asymmetric Synthesis of Aziridine-2-Carboxylic Esters

    Kattamuri, Padmanabha V.; Xiong, Yiwen; Pan, Yi; Li, Guigen


    Highly diastereoselective asymmetric synthesis of chiral aziridine-2-carboxylic esters is reported for 20 examples with good yields (51–87%) and excellent diastereoselectivities (>99:1 dr for most cases). The modified N-phosphonyl imines are proven to be superior to previous imine auxiliaries for the aza Darzens reaction by using secondary isopropyl to replace primary benzyl group for N,N-diamino protection. In the meanwhile, a special operation by slowly adding the pre-cooled imine solution at −78 °C into the preformed β-bromo lithium enolate mixture at this temperature in the presence of 4 Å molecular sieves was found to be crucial in terms of yields and diastereoselectivity. The present method can provide an easy and general access to β-hydroxy α-amino acids and other important amino building blocks. PMID:23563304

  9. Novel 1-[4-(Aminosulfonyl)phenyl]-1H-1,2,4-triazole derivatives with remarkable selective COX-2 inhibition: design, synthesis, molecular docking, anti-inflammatory and ulcerogenicity studies.

    Abuo-Rahma, Gamal El-Din A A; Abdel-Aziz, Mohamed; Farag, Nahla A; Kaoud, Tamer S


    A novel series of 1,2,4-triazole derivatives were synthesized and confirmed with different spectroscopic techniques. The prepared compounds exhibited remarkable anti-inflammatory activity comparable to that of indomethacin and celecoxib after 3 h. The tested compounds exhibited very low incidence of gastric ulceration compared to indomethacin. Most of the newly developed compounds showed excellent selectivity towards human COX-2 with selectivity indices (COX-1 IC50/COX-2 IC50) ranged from 62.5 to 2127. Docking studies results revealed that the highly selective tested compounds 6h and 6j showed lower CDOCKER energies, which means that they require less energy for proper interaction with the enzyme. The additional H-bonds with the oxygen of the amide and/or H of NH of the amide with the amino acid residues may be responsible for the higher binding affinity of this group of compounds towards COX-2.

  10. Enantioselective Synthesis of Protease Inhibitors and AntiHIV Agents

    WANG; Zhe


    Part 1: A highly enantio-and diastereoselective Ireland-Claisen rearrangement of chiral C3(acyloxy)-vinyl silanes for the synthesis of anti-disubstituted succinic acid, an important intermediate for matrix metalloprotease inhibitors, has been developed (enantio-and anti/syn selectivities up to 95% and 38/1). The diastereoselectivity of this reaction was found to be sensitive to remote hydroxyl protecting groups, for example, with-OMOM group, the anti/syn ratio was 19/1, while with-OTBDMS, the ratio was 38/1. The resultant Ireland-Claisen rearrangement product was applied to the synthesis of macrocyclic MMP inhibitors, such as SL 422.……

  11. Stereoselective total synthesis of the potent anti-asthmatic compound CMI-977 (LDP-977)

    Dias, Luiz Carlos; Farina, Lui Strambi; Ferreira, Marco Antonio Barbosa, E-mail: [Universidade de Campinas (UNICAMP), SP (Brazil). Instituto de Quimica


    A short and efficient stereoselective total synthesis of CMI-977 (LDP-977), a potent and orally active anti-asthmatic compound, was developed. The key steps involve a highly diastereoselective Mukaiyama oxidative cyclization, which provides the trans-THF (tetrahydrofuran) unit and a Seyferth-Gilbert homologation to construct the triple bond in the target molecule. The synthesis of the key chiral building block was performed using Jacobsen hydrolytic kinetic resolution. (author)

  12. Amplification of anti-diastereoselectivity via Curtin-Hammett effects in ruthenium-catalyzed hydrohydroxyalkylation of 1,1-disubstituted allenes: diastereoselective formation of all-carbon quaternary centers.

    Zbieg, Jason R; McInturff, Emma L; Leung, Joyce C; Krische, Michael J


    Under the conditions of ruthenium-catalyzed transfer hydrogenation, 1,1-disubstituted allenes 1a-c and alcohols 2a-g engage in redox-triggered generation of allylruthenium-aldehyde pairs to form products of hydrohydroxyalkylation 3a-g, 4a-g, and 5a-g with complete branched regioselectivity. By exploiting Curtin-Hammett effects, good to excellent levels of anti-diastereoselectivity (4:1 to >20:1) are obtained. Thus, all carbon quaternary centers are formed in a diastereoselective fashion upon carbonyl addition from the alcohol oxidation level in the absence of premetalated nucleophiles or stoichiometric byproducts. Exposure of allene 1b to equimolar quantities of alcohol 2a and aldehyde 6b under standard reaction conditions delivers adducts 4a and 4b in a 1:1 ratio. Similarly, exposure of allene 1b to equimolar quantities of aldehyde 6a and alcohol 2b provides adducts 4a and 4b in an identical equimolar ratio. Exposure of allene 1b to d(2)-p-nitrobenzyl alcohol, deuterio-2a, under standard reaction conditions delivers the product of hydrohydroxyalkylation, deuterio-4a, which incorporates deuterium at the carbinol position (>95% (2)H) and the interior vinylic position (34% (2)H). Competition experiments involving exposure of allene 1b to equimolar quantities of benzylic alcohols 2a and deuterio-2a reveal no significant kinetic effect. The collective data corroborate rapid, reversible alcohol dehydrogenation, allene hydrometalation, and (E)-, (Z)-isomerization of the transient allylruthenium in advance of turnover-limiting carbonyl addition. Notably, analogous allene-aldehyde reductive C-C couplings employing 2-propanol as the terminal reductant display poor levels of anti-diastereoselectivity, suggesting that carbonyl addition is not turnover-limiting in reactions conducted from the aldehyde oxidation level.

  13. Nanoparticles and self-organisation: the emergence of hierarchical properties from the nanoparticle soup (i.e., the small is getting bigger). Concluding remarks for Faraday Discussion: Nanoparticle Synthesis and Assembly.

    Schiffrin, David J


    Some four years ago, one of the participants in this Discussion (Prof. Nicholas Kotov) predicted that: "within five years we shall see multiple examples of electronic, sensor, optical and other devices utilizing self-assembled superstructures" (N. A. Kotov, J. Mater. Chem., 2011, 21, 16673-16674). Although this prediction came partially to fruition, we have witnessed an unprecedented interest in the properties of materials at the nanoscale. The point highlighted by Kotov, however, was the importance of self-assembly of structures from well characterised building blocks to yield hierarchical structures, hopefully with predictable properties, a concept that is an everyday pursuit of synthetic chemists. This Discussion has brought together researchers from a wide range of disciplines, i.e., colloid science, modelling, nanoparticle synthesis and organisation, magnetic and optical materials, and new imaging methods, within the excellent traditional Faraday Discussion format, to discuss advances in areas relevant to the main theme of the meeting.

  14. Unprecedented copper(I) bifluoride complexes: synthesis, characterization and reactivity.

    Vergote, Thomas; Nahra, Fady; Welle, Alexandre; Luhmer, Michel; Wouters, Johan; Mager, Nathalie; Riant, Olivier; Leyssens, Tom


    To be or not to bifluoride: Two synthetic pathways to unprecedented N-heterocyclic carbene copper(I) bifluoride complexes have been developed. Catalytic tests demonstrated that copper(I) bifluorides are very efficient catalysts, which do not require any additional activating agent. The first Cu-catalyzed diastereoselective allylation of (R)-N-tert-butanesulfinyl aldimines was also established. The method enables efficient, simple and general synthesis of enantiomerically enriched homoallylic amines at room temperature in high yields.

  15. Glycosyl Thioimidates as Versatile Building Blocks for Organic Synthesis

    Hasty, S. J.


    This review discusses the synthesis and application of glycosyl thioimidates in chemical glycosylation and oligosaccharide assembly. Although glycosyl thioimidates include a broad range of compounds, the discussion herein centers on S-benzothiazolyl (SBaz), S-benzoxazolyl (SBox), S-thiazolinyl (STaz), and S-benzimidazolyl (SBiz) glycosides. These heterocyclic moieties have recently emerged as excellent anomeric leaving groups that express unique characteristics for highly diastereoselective glycosylation and help to provide the streamlined access to oligosaccharides. PMID:24288416

  16. Chemo-, regio-, and diastereoselectivity preferences in the reaction of a sulfur ylide with a dienal and an enone.

    Janardanan, Deepa; Sunoj, Raghavan B


    Mechanistic insights into an interesting class of reaction between sulfur ylides with (i) a dienal, and (ii) an enone, obtained by using density functional theory, is reported. The kinetic and thermodynamic factors responsible for chemo-, regio-, and diastereoselectivities are established by identifying all key transition states and intermediates along the reaction pathway for 1,2-, 1,4-, and 1,6- modes of attack of dimethylsulfonium benzylide to 5-phenylpenta-2,4-dienal. The reaction profiles for 1,2- and 1,4- modes of addition are also evaluated for the reaction between dimethylsulfonium benzylide and pent-3-en-2-one. Our results show that the final outcome of the reaction with both these substrates would be decided by the interplay between kinetic and thermodynamic factors. It is found that the addition of a semi-stabilized ylide to conjugated carbonyl compounds prefers to proceed through a 1,4- (conjugate) pathway under thermodynamic conditions, which is in accordance with the available experimental reports. However, the formation of epoxides via a 1,2- (direct) addition pathway is computed to be equally competitive, which could be the favored pathway under kinetic conditions. Even though the lower barrier for the initial addition step is kinetically advantageous for the direct (or 1,2-) addition pathway, the higher energy of the betaine intermediates--as well as the reversibility of the accompanying elementary step--may disfavor product formation in this route. Thus, high diastereoselectivity in favor of 2,3-trans cyclopropanecarbaldehyde is predicted in the case of the dienal, using the most favored conjugate addition (1,4-addition) pathway. Along similar lines, ylide addition to the enone is identified to exhibit a preference toward conjugate addition over direct (1,2-) addition. The importance of transition state analysis in delineating the controlling factors towards product distribution and diastereoselectivity is established.

  17. N-Heterocyclic Carbene-Catalysed Diastereoselective Vinylogous Michael Addition Reaction of gamma-Substituted deconjugated Butenolides

    Guo, Hao


    An efficient N-heterocyclic carbene (NHC)-catalysed vinylogous Michael addition of deconjugated butenolides was developed. In the presence of 5 mol% of the NHC catalyst, both γ-alkyl and aryl-substituted deconjugated butenolides undergo vinylogous Michael addition with various α, β-unsaturated ketones, esters, or nitriles to afford γ,γ-disubstituted butenolides containing adjacent quaternary and tertiary carbon centers in good to excellent yields with excellent diastereoselectivities. In this process, the free carbene is assumed to act as a strong Brønsted base to promote the conjugate addition.

  18. Experimental and theoretical investigations of the stereoselective synthesis of p-stereogenic phosphine oxides.

    Copey, Laurent; Jean-Gérard, Ludivine; Framery, Eric; Pilet, Guillaume; Robert, Vincent; Andrioletti, Bruno


    An efficient enantioselective strategy for the synthesis of variously substituted phosphine oxides has been developed, incorporating the use of (1S,2S)-2-aminocyclohexanol as the chiral auxiliary. The method relies on three key steps: 1) Highly diastereoselective formation of P(V) oxazaphospholidine, rationalized by a theoretical study; 2) highly diastereoselective ring-opening of the oxazaphospholidine oxide with organometallic reagents that takes place with inversion of configuration at the P atom; 3) enantioselective synthesis of phosphine oxides by cleavage of the remaining P-O bond. Interestingly, the use of a P(III) phosphine precursor afforded a P-epimer oxazaphospholidine. Hence, the two enantiomeric phosphine oxides can be synthesized starting from either a P(V) or a P(III) phosphine precursor, which constitutes a clear advantage for the stereoselective synthesis of sterically hindered phosphine oxides.

  19. Highly diastereoselective dioxetane formation in the photooxygenation of enecarbamates with an oxazolidinone chiral auxiliary: steric control in the [2 + 2] cycloaddition of singlet oxygen through conformational alignment.

    Adam, Waldemar; Bosio, Sara G; Turro, Nicholas J


    The photooxygenation of oxazolidinone-substituted enecarbamates leads to diastereomerically pure dioxetanes. The high diastereoselectivity is rationalized in terms of effective pi-facial control achieved by shielding one side of the double bond with the chiral auxiliary. The absolute configuration of the dioxetanes is assigned by derivatization to diols.

  20. A novel chiral aliphatic-aromatic diamine promoted direct, highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins under solvent-free conditions.

    Miao, Shifeng; Bai, Jinjin; Yang, Jin; Zhang, Yawen


    A series of new highly efficient chiral aliphatic-aromatic diamine catalysts have been designed and successfully applied to the asymmetric Michael addition of cyclohexanone with nitroolefins under solvent-free conditions without any acidic additives. The desired adducts were obtained in high yields with excellent enantio- and diastereoselectivities of syn products (up to >99% ee, >99:1 dr).

  1. IBX-mediated oxidation of unactivated cyclic amines: application in highly diastereoselective oxidative Ugi-type and aza-Friedel-Crafts reactions.

    de Graaff, C; Bensch, L; van Lint, Matthijs J; Ruijter, E; Orru, R V A


    The first o-iodoxybenzoic acid (IBX) mediated oxidation of unactivated amines to imines is described. A range of meso-pyrrolidines were shown to be suitable substrates. The chemical space was further explored with one-pot oxidative Ugi-type and aza-Friedel-Crafts reactions, which proved to be highly diastereoselective.

  2. Highly enantio- and diastereoselective one-pot reactions in aqueous media : Combined asymmetric Rh-catalyzed conjugate addition/metal-mediated allylation

    Kallstrom, Sara; Jagt, Richard B. C.; Sillanpaa, Reijo; Feringa, Ben L.; Minnaard, Adriaan J.; Leino, Reko; Källström, Sara; Sillanpää, Reijo


    1,3-Disubstituted, enantiopure cyclohexanols have been prepared in very high diastereoselectivities and good yields by a concise one-pot method combining the enantioselective rhodium-catalyzed conjugate addition of arylboronic acids with indium-mediated allylation into a highly efficient one-pot rea

  3. Bromoporphyrins as versatile synthons for modular construction of chiral porphyrins: cobalt-catalyzed highly enantioselective and diastereoselective cyclopropanation.

    Chen, Ying; Fields, Kimberly B; Zhang, X Peter


    5,10-Bis(2',6'-dibromophenyl)porphyrins bearing various substituents at the 10 and 20 positions were demonstrated to be versatile synthons for modular construction of chiral porphyrins via palladium-catalyzed amidation reactions with chiral amides. The quadruple carbon-nitrogen bond formation reactions were accomplished in high yields with different chiral amide building blocks under mild conditions, forming a family of D2-symmetric chiral porphyrins. Cobalt(II) complexes of these chiral porphyrins were prepared in high yields and shown to be active catalysts for highly enantioselective and diastereoselective cyclopropanation under a practical one-pot protocol (alkenes as limiting reagents and no slow addition of diazo reagents).

  4. Enantioselective and diastereoselective separation of synthetic pyrethroid insecticides on a novel chiral stationary phase by high-performance liquid chromatography.

    Tan, Xulin; Hou, Shicong; Wang, Min


    A novel chiral packing material for high-performance liquid chromatography (HPLC) was prepared by connecting (R)-1-phenyl-2-(4-methylphenyl) ethylamine (PTE) amide derivative of (S)-isoleucine to aminopropyl silica gel through 2-amino-3,5-dinitro-1-carboxamido-benzene unit. This chiral stationary phase was applied to the enantioselective and diastereoselective separation of five pyrethroid insecticides by HPLC under normal phase condition. To achieve satisfactory baseline separation an optimization of the variables of mobile phase composition was required. The two enantiomers of fenpropathrin and four stereoisomers of fenvalerate were baseline separated using hexane-1,2-dichloroethane-2-propanol as mobile phase. The results show that the enantioselectivity of CSP is better than Pirkle type 1-A column for these compounds. Only partial separations for the cypermethrin and cyfluthrin stereoisomers were observed. Seven peaks and eight peaks were observed for cypermethrin and cyfluthrin, respectively. The elution orders were assigned by using different stereoisomer-enriched products.

  5. Cascade Synthesis of Five-Membered Lactones using Biomass-Derived Sugars as Carbon Nucleophiles.

    Yamaguchi, Sho; Matsuo, Takeaki; Motokura, Ken; Miyaji, Akimitsu; Baba, Toshihide


    We report the cascade synthesis of five-membered lactones from a biomass-derived triose sugar, 1,3-dihydroxyacetone, and various aldehydes. This achievement provides a new synthetic strategy to generate a wide range of valuable compounds from a single biomass-derived sugar. Among several examined Lewis acid catalysts, homogeneous tin chloride catalysts exhibited the best performance to form carbon-carbon bonds. The scope and limitations of the synthesis of five-membered lactones using aldehyde compounds are investigated. The cascade reaction led to high product selectivity as well as diastereoselectivity, and the mechanism leading to the diastereoselectivity was discussed based on isomerization experiments and density functional theory (DFT) calculations. The present results are expected to support new approaches for the efficient utilization of biomass-derived sugars.

  6. Introductory Remarks to the "Edward Teller Lectures"

    Hora, Heinrich; Miley, George H.


    The following sections are included: * Overview * Big Laser Solution * Physics of the Fast Igniter * Fast Igniter for Electron Beam Fusion * Block Igniter for Producing Ion Beam Ignition * Concluding Remarks * References

  7. Research use of patented inventions: opening remarks

    Fernández de Labastida, José M.


    Opening remarks for the 2006 conference in Madrid on the research use of patented inventions. The conference, which was held at CSIC on 18-19 May 2006, was jointly organised by the Spanish National Research Council (CSIC), the Spanish Patent and Trademark Office (OEPM) and the OECD, with support from the European Patent Office (EPO) through its European Patent Academy. The conference brochure is also included as an attachment to the Opening remarks file.

  8. Facile, Regio- and Diastereoselective Synthesis of Spiro-Pyrrolidine and Pyrrolizine Derivatives and Evaluation of Their Antiproliferative Activities

    Abdulrahman I. Almansour


    Full Text Available A number of novel spiro-pyrrolidines/pyrrolizines derivatives were synthesized through [3+2]-cycloaddition of azomethine ylides with 3,5-bis[(E-arylmethylidene]tetrahydro-4(1H-pyridinones 2a–n. Azomethine ylides were generated in situ from the reaction of 1H-indole-2,3-dione (isatin, 3 with N-methylglycine (sarcosine, phenylglycine, or proline. All compounds (50 μM were evaluated for their antiproliferative activity against human breast carcinoma (MDA-MB-231, leukemia lymphoblastic (CCRF-CEM, and ovarian carcinoma (SK-OV-3 cells. N-α-Phenyl substituted spiro-pyrrolidine derivatives (5a–n showed higher antiproliferative activity in MDA-MB-231 than other cancer cell lines. Among spiro-pyrrolizines 6a–n, a number of derivatives including 6a–c and 6i–m showed a comparable activity with doxorubicin in all three cell lines. Among all compounds in three classes, 6a, 6b, and 6m, were found to be the most potent derivatives showing 64%, 87%, and 74% antiproliferative activity in MDA-MB-231, SK-OV-3, and CCRF-CEM cells, respectively. Compound 6b showed an IC50 value of 3.6 mM in CCRF-CEM cells. These data suggest the potential antiproliferative activity of spiro-pyrrolidines/pyrrolizines.

  9. Anatomy of phobanes. diastereoselective synthesis of the three isomers of n-butylphobane and a comparison of their donor properties.

    Carreira, Monica; Charernsuk, Manutsavin; Eberhard, Michael; Fey, Natalie; van Ginkel, Roel; Hamilton, Alex; Mul, Wilhelmus P; Orpen, A Guy; Phetmung, Hirihataya; Pringle, Paul G


    Three methods for the large scale (50-100 g) separation of the secondary phobanes 9-phosphabicyclo[3.3.1]nonane (s-PhobPH) and 9-phosphabicyclo[4.2.1]nonane (a-PhobPH) are described in detail. Selective protonation of s-PhobPH with aqueous HCl in the presence of a-PhobPH is an efficient way to obtain large quantities of a-PhobPH. Selective oxidation of a-PhobPH in an acidified mixture of a-PhobPH and s-PhobPH is an efficient way to obtain large quantities of s-PhobPH. The crystalline, air-stable phosphonium salts [s-PhobP(CH(2)OH)(2)]Cl and [a-PhobP(CH(2)OH)(2)]Cl can be separated by a selective deformylation with aqueous NaOH. a-PhobPH is shown to be a(5)-PhobPH in which the H lies over the five-membered ring. The isomeric a(7)-PhobPH has been detected but isomerizes to a(5)-PhobPH rapidly in the presence of water. s-PhobPH is more basic than a-PhobPH by about 2 pK(a) units in MeOH. Treatment of s-PhobPH with BH(3).THF gives s-PhobPH(BH(3)) and similarly a-PhobPH gives a(5)-PhobPH(BH(3)). Isomerically pure s-PhobPCl and a(5)-PhobPCl are prepared by reaction of the corresponding PhobPH with C(2)Cl(6). The n-butyl phobane s-PhobPBu is prepared by nucleophilic (using s-PhobPH or s-PhobPLi) and electrophilic (using s-PhobPCl) routes. Isomerically pure a(5)-PhobPBu is prepared by treatment of a-PhobPLi with (n)BuBr and a(7)-PhobPBu is prepared by quaternization of a-PhobPH with (n)BuBr followed by deprotonation. From the rates of conversion of a(7)-PhobPBu to a(5)-PhobPBu, the DeltaG(double dagger) (403 K) for P-inversion is calculated to be 38.1 kcal mol(-1) (160 kJ mol(-1)). The donor properties of the individual isomers of PhobPBu were assessed from the following spectroscopic measurements: (i) (1)J(PSe) for PhobP(Se)Bu; (ii) nu(CO) for trans-[RhCl(CO)(PhobPBu)(2)], (iii) (1)J(PtP) for the PEt(3) in trans-[PtCl(2)(PEt(3))(PhobPBu)]. In each case, the data are consistent with the order of sigma-donation being a(7)-PhobPBu > s-PhobPBu > a(5)-PhobPBu. This same order was found when the affinity of the PhobPBu isomers for platinum(II) was investigated by determining the relative stabilities of [Pt(CH(3))(s-PhobPBu)(dppe)][BPh(4)], [Pt(CH(3))(a(5)-PhobPBu)(dppe)][BPh(4)], and [Pt(CH(3))(a(7)-PhobPBu)(dppe)][BPh(4)] from competition experiments. Calculations of the relative stabilities of the isomers of PhobPH, [PhobPH(2)](+), and PhobPH(BH(3)) support the conclusions drawn from the experimental results. Moreover, calculations on the frontier orbital energies of PhobPMe isomers and their binding energies to H(+), BH(3), PdCl(3)(-), and PtCl(3)(-) corroborate the experimental observation of the order of sigma-donation being a(7)-PhobPR > s-PhobPR > a(5)-PhobPR. The calculated He(8) steric parameter shows that the bulk of the isomers increases in the order a(7)-PhobPR < s-PhobPR < a(5)-PhobPR. The crystal structures of [a-PhobP(CH(2)OH)(2)][s-PhobP(CH(2)OH)(2)]Cl(2), cis-[PtCl(2)(a(5)-PhobPCH(2)OH)(2)], trans-[PtCl(2)(s-PhobPBu)(2)], and trans-[PtCl(2)(a(7)-PhobPBu)(2)] are reported.

  10. Asymmetric syntheses and transformations--tools for chirality multiplication in drug synthesis.

    Gawroński, Jacek


    A review of currently used methods for the synthesis and resolution of enantiomers of drugs and their precursors is presented. For the synthesis part the methods of diastereoselective as well as enantioselective synthesis are discussed, with particular consideration given to enantioselective catalysis with either metal complexes or biocatalysts. Desymmetrization processes are also included as methods to access enantiomerically pure compounds. Racemate resolution still remains an important method to obtain pure enantiomers and methods involving kinetic resolution in enzymatic or chemical systems, and particularly in connection with racemization (dynamic kinetic resolution) are on the rise in fine chemical industry, when applicable.

  11. Protecting-Group-Free Synthesis of 2-Deoxy-Aza-Sugars

    Mattie Simon Maria Timmer


    Full Text Available The protecting-group-free asymmetric synthesis of 1,2,4-trideoxy-1,4-imino-L-xylitol is readily achieved in five steps from 2-deoxy-D-ribose and with an overall yield of 48%. Key in this synthesis is the application of our recently developed Vasella-reductive amination and carbamate annulation methodologies to the synthesis of 2-deoxy-aza-sugars. The carbamate annulation occurred with excellent yield and diastereoselectively (>20:1 d.r., in favour of the 3,4-cis isomer.

  12. Rh(III)-Catalyzed Cyclopropanation Initiated by C–H Activation: Ligand Development Enables a Diastereoselective [2 + 1] Annulation of N-Enoxyphthalimides and Alkenes


    N-Enoxyphthalimides undergo a Rh(III)-catalyzed C–H activation initiated cyclopropanation of electron deficient alkenes. The reaction is proposed to proceed via a directed activation of the olefinic C–H bond followed by two migratory insertions, first across the electron-deficient alkene and then by cyclization back onto the enol moiety. A newly designed isopropylcyclopentadienyl ligand drastically improves yield and diastereoselectivity. PMID:25093811

  13. Enantioselective Synthesis of Antiepileptic Drug: (-)-Levetiracetam—Synthetic Applications of the Versatile New Chiral N-Sulfinimine

    Chandra Babu, K.; Buchi Reddy, R.; E. Naresh; Ram Mohan, K.; Madhusudhan, G.; Mukkanti, K.


    We report an asymmetric synthesis of (-)-Levetiracetam (1) in six steps starting from versatile new chiral N-sulfinimine (3). The key step, stereoselective 1,2-addition of ethylmagnesium bromide (EtMgBr) to chiral N-sulfinimine derived from (R)-glyceraldehyde acetonide and (S)-t-BSA, gave the corresponding sulfonamide (2) in high diastereoselectivity. Simultaneous deprotection and deacetylation followed by NaIO4 cleavage and reduction gave β-amino alcohol (6). Subsequent reactions yielded th...

  14. Remote Stereoinductive Intramolecular Nitrile Oxide Cycloaddition: Asymmetric Total Synthesis and Structure Revision of (-)-11β-Hydroxycurvularin.

    Choe, Hyeonjeong; Pham, Thuy Trang; Lee, Joo Yun; Latif, Muhammad; Park, Haeil; Kang, Young Kee; Lee, Jongkook


    The first total synthesis and structure revision of (-)-11β-hydroxycurvularin (1b), a macrolide possessing a β-hydroxyketone moiety, were accomplished. The β-hydroxyketone moiety in this natural product was introduced by cleavage of the N-O bond in an isoxazoline ring that was formed diastereoselectively in a 1,5-remote stereocontrolled fashion by employing intramolecular nitrile oxide cycloaddition.

  15. Transition metal-free generation of N-unsubstituted imines from benzyl azides: synthesis of N-unsubstituted homoallylic amines.

    Pramanik, Suman; Reddy, Reddy Rajasekhar; Ghorai, Prasanta


    An efficient transition metal-free approach for the generation of N-unsubstituted imines from azides followed by trapping with allyl nucleophile to provide N-unsubstituted homoallylic amines has been described. Although catalytic KO(t)Bu in DMSO is sufficient to allow imine generation, stoichiometric KO(t)Bu is essential in THF. Further, an enantio- and diastereoselective synthesis of homoallylic amines from benzyl azide has also been exemplified.

  16. Organocatalytic Asymmetric Synthesis of Functionalized 1,3,5-Triarylpyrrolidin-2-ones via an Aza-Michael/Aldol Domino Reaction.

    Joie, Céline; Deckers, Kristina; Enders, Dieter


    The organocatalytic asymmetric synthesis of functionalized 1,3,5-triarylpyrrolidin-2-ones bearing three contiguous stereocenters through an aza-Michael/aldol domino reaction of α-ketoamides with α,β-unsaturated aldehydes is described. The domino products were further derivatized by aldehyde olefination under one-pot conditions. The reaction proceeds with excellent diastereoselectivities (>20:1) and good to excellent enantioselectivities (60-96% ee).

  17. Remarks on the system of the Spermatophytes

    Pulle, A.


    For the group of plants treated in the “Compendium” I have used the name Spermatophyta. WETTSTEIN in his “Handbuch” remarks that this name is incorrect because in botany the word “sperma” is used for spermatozoids, and from the name Spermatophyta it might be concluded that by it “plants with spermat

  18. Concluding remarks: from match to flamethrower.

    Poliakoff, Martyn


    These remarks give some impressions of Faraday Discussion 152 from the point of view of an outsider and suggest a number of actions which might help bind the Gold Catalysis Community more strongly and increase the long term impact of their science.

  19. Stereoselective Synthesis of α-Aminonitril on Glucose Templates

    ZHANG Peng-Fei; GU Yi-Xin; GUO Jun-Li; CHEN Min


    @@ Both proteinogenic and non proteinogenic α-amino acids are of particular interest as constituents of peptide factors, peptidomimetics and antibiotics for the construction of modern selective drugs. [1] Furthemore, α-amino acid derivatives are interesting building units for chiral-pool syntheses of enantiomerically pure natural products. [2] Numerous efforts in modern organic synthesis are centered on the synthesis of enantiomerically pure α-amino acids. [3] During the past three decades efficient methods of asymmetric synthesis of α-amino acids have been developed; most of them are based on electrophilic transformations of organometallic intermediates. [4] Using the concept that the chirality of the carbohydrates can be exploited for diastereoselective reactions, Kunz and his cooperator had developed a Strecker synthesis with glycosyl amines as chiral auxiliaries. [5

  20. Chemoenzymatic collective synthesis of optically active hydroxyl(methyl)tetrahydronaphthalene-based bioactive terpenoids.

    Batwal, Ramesh U; Argade, Narshinha P


    Starting from succinic anhydride and 2-methylanisole, a chemoenzymatic collective formal/total synthesis of several optically active tetrahydronaphthalene based bioactive natural products has been presented via advanced level common precursors; the natural product and antipode (-)/(+)-aristelegone B. Regioselective benzylic oxidations, stereoselective introduction of hydroxyl groups at the α-position of ketone moiety in syn-orientation, efficient enzymatic resolutions with high enantiomeric purity, stereoselective reductions, samarium iodide induced deoxygenations and tandem acylation-Wittig reactions without racemization and/or eliminative aromatization were the key features. An attempted diastereoselective synthesis of (±)-vallapin has also been described.

  1. Theoretical investigations of the reaction between 1,4-dithiane-2,5-diol and azomethine imines: mechanisms and diastereoselectivity.

    Zheng, Linjie; Qiao, Yan; Lu, Mengxue; Chang, Junbiao


    In the present study, mechanistic insights into the domino reaction between 1,4-dithiane-2,5-diol and azomethine imines were derived from the computational study with B3LYP and M06-2X functionals. On the whole, the domino process comprises two consecutive reactions: cleavage of 1,4-dithiane-2,5-diol leading to mercaptoacetaldehyde and [3 + 3] cycloaddition of mercaptoacetaldehyde with azomethine imines. The cleavage of 1,4-dithiane-2,5-diol can take place via multiple possible pathways (1A-1E), and pathway 1E in which double-methanol molecules mediate the proton transfer process is the most energetically favorable, with an energy barrier of 19.9 kcal mol(-1). For the [3 + 3] cycloaddition, three possible pathways (2F-2H) were explored. The calculated energy profiles reveal that pathway 2H with activation energies ranging from 6.9 to 10.2 kcal mol(-1) is more energetically favorable than pathways 2F and 2G. Specifically, pathway 2H comprises three reaction steps: deprotonation of mercaptoacetaldehyde by DABCO allows for the formation of the thiol anion, which subsequently launches a nucleophilic attack on azomethine imines followed by intramolecular cyclization resulting in the final products. The calculated results are in agreement with the experimental observations that the reaction can proceed most efficiently in the presence of both DABCO and methanol. Furthermore, the hydrogen bonding interaction is identified to be the main factor determining the observed diastereoselectivity The current systematic theoretical study gives a full scenario of the reaction between 1,4-dithiane-2,5-diol and azomethine imines catalyzed by DABCO, and thus provides some valuable clues for further investigation and development of this kind of important reaction.

  2. Catalytic Asymmetric Piancatelli Rearrangement: Brønsted Acid Catalyzed 4π Electrocyclization for the Synthesis of Multisubstituted Cyclopentenones

    Cai, Yunfei


    The first catalytic asymmetric Piancatelli reaction is reported. Catalyzed by a chiral Brønsted acid, the rearrangement of a wide range of furylcarbinols with a series of aniline derivatives provides valuable aminocyclopentenones in high yields as well as excellent enantioselectivities and diastereoselectivities. The high value of the aza-Piancatelli rearrangement was demonstrated by the synthesis of a cyclopentane-based hNK1 antagonist analogue.

  3. Some remarks on word formation in Danish

    Götzsche, Hans

    , there are some patterns for these Danish compounds concerning their internal semantics, in that the same lexical items may be used for different purposes depending on whether they are formed as a straightforward linear sequence (a word formation) or a reversed sequence (a phrase). The problem is (i) how the two......Abstract for the 25th Scandinavian Conference of Linguistics Some remarks on wordformation in Danish Some Danish word formation phenomena pose a problem for the linguist, being a predicament for analysis. In Danish a train leaves the station when it afgår ‘leaves’, while a minister may gå af...

  4. A remarkable representation of the Clifford group

    Bengtsson, Ingemar


    The finite Heisenberg group knows when the dimension of Hilbert space is a square number. Remarkably, it then admits a representation such that the entire Clifford group --- the automorphism group of the Heisenberg group --- is represented by monomial phase-permutation matrices. This has a beneficial influence on the amount of calculation that must be done to find Symmetric Informationally Complete POVMs. I make some comments on the equations obeyed by the absolute values of the components of the SIC vectors, and on the fact that the representation partly suggests a preferred tensor product structure.

  5. Remarks on scale separation in flux vacua

    Gautason, F F; Van Riet, T; Williams, M


    We argue that the Maldacena-Nunez no-go theorem excluding Minkowski and de Sitter vacua in flux compactifications can be extended to exclude anti-de Sitter (AdS) vacua for which the Kaluza-Klein scale is parametrically smaller than the AdS length scale. As a practical application of this observation we demonstrate that the mechanism to resolve O6 singularities in massive type IIA at the classical level is likely not to occur in AdS compactifications with scale separation. We furthermore remark that a compactification to four observable dimensions implies a large cosmological hierarchy.

  6. Catalytic diastereoselective tandem conjugate addition-elimination reaction of Morita-Baylis-Hillman C adducts by C-C bond cleavage

    Yang, Wenguo


    Through the cleavage of the C-C bond, the first catalytic tandem conjugate addition-elimination reaction of Morita-Baylis-Hillman C adducts has been presented. Various S N2′-like C-, S-, and P-allylic compounds could be obtained with exclusive E configuration in good to excellent yields. The Michael product could also be easily prepared by tuning the β-C-substituent group of the α-methylene ester under the same reaction conditions. Calculated relative energies of various transition states by DFT methods strongly support the observed chemoselectivity and diastereoselectivity. © 2012 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.

  7. Remarks on scale separation in flux vacua

    Gautason, F. F.; Schillo, M.; Van Riet, T.; Williams, M.


    We argue that the Maldacena-Nuñez no-go theorem excluding Minkowski and de Sitter vacua in flux compactifications can be extended to anti-de Sitter (AdS) vacua for which the Kaluza-Klein scale is parametrically smaller than the AdS length scale. In the absence of negative tension sources, scale-separated AdS vacua are ruled out in 11-dimensional supergravity; in 10-dimensional supergravity, we show that such vacua can only arise in conjunction with large dilaton gradients. As a practical application of this observation we demonstrate that the mechanism to resolve O6 singularities in massive type IIA at the classical level is likely not to occur in AdS compactifications with scale separation. We furthermore remark that a compactification to four observable dimensions implies a large cosmological hierarchy.

  8. Noncovalent Substrate-Directed Enantioselective Heck Reactions: Synthesis of S- and P-Stereogenic Heterocycles.

    de Azambuja, Francisco; Carmona, Rafaela C; Chorro, Tomaz H D; Heerdt, Gabriel; Correia, Carlos Roque D


    S- and P-Stereogenic heterocycles were synthesized by a remarkably simple enantioselective Heck desymmetrization reaction based on the unprecedented noncovalent directing effect of S=O and P=O functionalities. Selected prochiral symmetric substrates were efficiently arylated using the recently disclosed chiral PyraBOx ligand under mild and open-flask reaction conditions. Several five-membered aryl- sulfones, sulfoxides, and phosphine oxides were synthesized in good to excellent yields, in good to high diastereoselectivity, and enantiomeric ratios up to 98:2. Theoretical calculations also support the noncovalent directing effect of the S=O and P=O functionalities during the arylation process.

  9. Remarkable selective constraints on exonic dinucleotide repeats.

    Haasl, Ryan J; Payseur, Bret A


    Long dinucleotide repeats found in exons present a substantial mutational hazard: mutations at these loci occur often and generate frameshifts. Here, we provide clear and compelling evidence that exonic dinucleotides experience strong selective constraint. In humans, only 18 exonic dinucleotides have repeat lengths greater than six, which contrasts sharply with the genome-wide distribution of dinucleotides. We genotyped each of these dinucleotides in 200 humans from eight 1000 Genomes Project populations and found a near-absence of polymorphism. More remarkably, divergence data demonstrate that repeat lengths have been conserved across the primate phylogeny in spite of what is likely considerable mutational pressure. Coalescent simulations show that even a very low mutation rate at these loci fails to explain the anomalous patterns of polymorphism and divergence. Our data support two related selective constraints on the evolution of exonic dinucleotides: a short-term intolerance for any change to repeat length and a long-term prevention of increases to repeat length. In general, our results implicate purifying selection as the force that eliminates new, deleterious mutants at exonic dinucleotides. We briefly discuss the evolution of the longest exonic dinucleotide in the human genome--a 10 x CA repeat in fibroblast growth factor receptor-like 1 (FGFRL1)--that should possess a considerably greater mutation rate than any other exonic dinucleotide and therefore generate a large number of deleterious variants. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  10. Remarkable evolutionary conservation of SOX14 orthologues

    Jelena Popovic; Milena Stevanovic


    SOX proteins constitute a large family of diverse, well-conserved transcription factors present in vertebrates and invertebrates, and also implicated in control of many developmental processes. Our objectives have been to identify Sox14 gene of goat (Capra hircus), cow (Bos taurus) and rat (Rattus norvegicus), and to perform comparative analyses and mapping of SOX14 orthologues from numerous vertebrate species. PCR based approach was used to identify Sox14 of goat, cow and rat, while nucleotide and amino acid sequence alignments and mapping were performed using information currently available in public database. Comparative sequence analysis revealed remarkable identity among Sox14 orthologues and helped us to identify highly conserved motifs that represent molecular signatures of SOX14 protein that might have structural or functional significance. Further, we determined chromosomal locations of numerous predicted group B Sox genes and their neighbouring genes using currently available genome database. In conclusion, our study has not only supported the proposed model of group B Sox genes evolution in chicken and mammals, but has also revealed that additional evolutionary events split Sox B genes into different chromosomes in some mammals. Mapping data presented in this study could help in refining the understanding of the evolution of group B Sox genes in vertebrates.

  11. The end of a remarkable era


    An important era in particle physics is coming to an end: the US Department of Energy announced on Monday that it will not fund an extension to Tevatron running beyond 2011. It is a poignant moment for particle physics as we prepare to bid farewell to a machine that has changed our view of the Universe, and played a significant role in paving the way for the new era that is opening up with the LHC.   The Tevatron has been at the high-energy frontier of particle physics for over a quarter of a century. That’s a remarkable achievement by any account, and the physics results are there to prove it. As well as bringing us the discovery of the top quark in 1995, the Tevatron’s experiments have provided vitally important precision measurements covering the full spectrum of Standard Model physics, not to mention hints of what may lie beyond. With several months of running still to come, it would be a foolish gambler who bet against further new physics emerging before the Teva...

  12. Carbon Capture and Storage: concluding remarks.

    Maitland, G C


    This paper aims to pull together the main points, messages and underlying themes to emerge from the Discussion. It sets these remarks in the context of where Carbon Capture and Storage (CCS) fits into the spectrum of carbon mitigation solutions required to meet the challenging greenhouse gas (GHG) emissions reduction targets set by the COP21 climate change conference. The Discussion focused almost entirely on carbon capture (21 out of 23 papers) and covered all the main technology contenders for this except biological processes. It included (chemical) scientists and engineers in equal measure and the Discussion was enriched by the broad content and perspectives this brought. The major underlying theme to emerge was the essential need for closer integration of materials and process design - the use of isolated materials performance criteria in the absence of holistic process modelling for design and optimisation can be misleading. Indeed, combining process and materials simulation for reverse materials molecular engineering to achieve the required process performance and cost constraints is now within reach and is beginning to make a significant impact on optimising CCS and CCU (CO2 utilisation) processes in particular, as it is on materials science and engineering generally. Examples from the Discussion papers are used to illustrate this potential. The take-home messages from a range of other underpinning research themes key to CCUS are also summarised: new capture materials, materials characterisation and screening, process innovation, membranes, industrial processes, net negative emissions processes, the effect of GHG impurities, data requirements, environment sustainability and resource management, and policy. Some key points to emerge concerning carbon transport, utilisation and storage are also included, together with some overarching conclusions on how to develop more energy- and cost-effective CCS processes through improved integration of approach across the

  13. Asymmetric synthesis of α-amino-1,3-dithianes via chiral N-phosphonyl imine-based Umpolung reaction without using chromatography and recrystallization.

    Kattamuri, Padmanabha V; Ai, Teng; Pindi, Suresh; Sun, Yinwei; Gu, Peng; Shi, Min; Li, Guigen


    A series of α-amino-1,3-dithianes have been synthesized via the asymmetric Umpolung reaction of 2-lithio-1,3-dithianes with chiral N-phosphonyl imines in good chemical yields (up to 82%) and good to excellent diastereoselectivities (>99:1). The manner by which chiral N-phosphonyl imines are slowly added into the solution of 2-lithio-1,3-dithiane was found to be crucial for achieving excellent diastereoselectivity. The current synthesis was proven to follow the GAP chemistry (group-assistant-purification chemistry) process, which avoids traditional purification techniques of chromatography or recrystallization, i.e., the pure chiral α-amino-1,3-dithianes attached with the chiral N-phosphonyl group were readily obtained by washing the solid crude products with hexane or a mixture of hexane-ethyl acetate.

  14. Lewis acid catalyzed cyclization of glycals/2-deoxy-D-ribose with arylamines: additional findings on product structure and reaction diastereoselectivity.

    Du, Chengtang; Li, Fulong; Zhang, Xuefeng; Hu, Wenxiang; Yao, Qizheng; Zhang, Ao


    The cyclization reactions of arylamines with 2-deoxy-D-ribose or glycals were reinvestigated in the current report. In the montmorillonite KSF- or InCl(3)-initiated reactions of 2-deoxy-D-ribose with arylamines, a pair of diastereomeric tetrahydro-2H-pyran-fused tetrahydroquinolines was obtained in a nearly 1:1 ratio where the structure of one diastereomer was incorrectly assigned in the literature. Meanwhile, the diastereoselectivity in InBr(3)-catalyzed cyclization of glycals with arylamines was also incorrectly reported previously. It was found that high diastereomeric selectivity was achieved only when a C5-substituted glycal was used; otherwise, a pair of diastereomers was obtained in moderate yield with 1:1 diastereomeric ratio. Furthermore, tetrahydrofuran-fused tetrahydroquinolines 5b and 5b' were also prepared successfully by using TBDPS-protected ribose as the glycal precursor and montmorillonite KSF as the activator.

  15. Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

    László Tóth


    Full Text Available Condensed O,N-heterocycles containing tetrahydro-1,4-benzoxazepine and tetrahydroquinoline moieties were prepared by a regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction of a 4-aryl-2-phenyl-1,4-benzoxazepine derivative obtained from flavanone. The relative configuration of products were determined by the correlation of 3JH,H coupling data with the geometry of major conformers accessed by DFT conformational analysis. Separated enantiomers of the products were characterized by HPLC-ECD data, which allowed their configurational assignment on the basis of TDDFT-ECD calculation of the solution conformers. Two compounds showed neuroprotective activities against hydrogen peroxide (H2O2 or β-amyloid25–35 (Aβ25–35-induced cellular injuries in human neuroblastoma SH-SY5Y cells in the range of those of positive controls.

  16. Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel-[1,5]-hydride shift cyclization reaction.

    Tóth, László; Fu, Yan; Zhang, Hai Yan; Mándi, Attila; Kövér, Katalin E; Illyés, Tünde-Zita; Kiss-Szikszai, Attila; Balogh, Balázs; Kurtán, Tibor; Antus, Sándor; Mátyus, Péter


    Condensed O,N-heterocycles containing tetrahydro-1,4-benzoxazepine and tetrahydroquinoline moieties were prepared by a regio- and diastereoselective domino Knoevenagel-[1,5]-hydride shift cyclization reaction of a 4-aryl-2-phenyl-1,4-benzoxazepine derivative obtained from flavanone. The relative configuration of products were determined by the correlation of (3) J H,H coupling data with the geometry of major conformers accessed by DFT conformational analysis. Separated enantiomers of the products were characterized by HPLC-ECD data, which allowed their configurational assignment on the basis of TDDFT-ECD calculation of the solution conformers. Two compounds showed neuroprotective activities against hydrogen peroxide (H2O2) or β-amyloid25-35 (Aβ25-35)-induced cellular injuries in human neuroblastoma SH-SY5Y cells in the range of those of positive controls.

  17. Asymmetric synthesis of quaternary aryl amino acid derivatives via a three-component aryne coupling reaction

    Elizabeth P. Jones


    Full Text Available A method was developed for the synthesis of α-alkyl, α-aryl-bislactim ethers in good to excellent yields and high diastereoselectivities, consisting of a facile one-pot procedure in which the aryl group is introduced by means of a nucleophilic addition to benzyne and the alkyl group by alkylation of a resultant benzylic anion. Hydrolysis of the sterically less hindered adducts gave the corresponding quaternary amino acids with no racemization, whereas hydrolytic ring opening gave the corresponding valine dipeptides from bulkier bislactims.

  18. The direct oxidative diene cyclization and related reactions in natural product synthesis

    Juliane Adrian


    Full Text Available The direct oxidative cyclization of 1,5-dienes is a valuable synthetic method for the (diastereoselective preparation of substituted tetrahydrofurans. Closely related reactions start from 5,6-dihydroxy or 5-hydroxyalkenes to generate similar products in a mechanistically analogous manner. After a brief overview on the history of this group of transformations and a survey on mechanistic and stereochemical aspects, this review article provides a summary on applications in natural product synthesis. Moreover, current limitations and future directions in this area of chemistry are discussed.

  19. Organocatalytic cascade aza-Michael/hemiacetal reaction between disubstituted hydrazines and α,β-unsaturated aldehydes: Highly diastereo- and enantioselective synthesis of pyrazolidine derivatives

    Zhi-Cong Geng


    Full Text Available The catalytic synthesis of nitrogen-containing heterocycles is of great importance to medicinal and synthetic chemists, and also a challenge for modern chemical methodology. In this paper, we report the synthesis of pyrazolidine derivatives through a domino aza-Michael/hemiacetal sequence with chiral or achiral secondary amines as organocatalysts. Thus, a series of achiral pyrazolidine derivatives were obtained with good yields (up to 90% and high diastereoselectivities (>20:1 with pyrrolidine as an organocatalyst, and enantioenriched pyrazolidines are also achieved with good results (up to 86% yield, >10/1 regioselectivity, >20:1 dr, 99% ee in the presence of (S-diphenylprolinol trimethylsilyl ether catalyst.

  20. Organobase catalyzed 1,4-conjugate addition of 4-hydroxycoumarin on chalcones: Synthesis, NMR and single-crystal X-ray diffraction studies of novel warfarin analogues

    Talhi, Oualid; Fernandes, José A.; Pinto, Diana C. G. A.; Almeida Paz, Filipe A.; Silva, Artur M. S.


    The synthesis of a new series of warfarin analogues by convenient organobase catalyzed 1,4-conjugate addition of 4-hydroxycoumarin to chalcone derivatives is described. 1H NMR spectroscopy evidenced the presence of a predominant acyclic open-form together with the cyclic hemiketal tautomers of the resulting Michael adducts. The acyclic open-form has been unequivocally proved by single-crystal X-ray diffraction analysis. The use of the B ring ortho-hydroxychalcone synthons in this reaction has led to a diastereoselective synthesis of warfarin bicyclo[3.3.1]nonane ketal derivatives.

  1. Applications of the Wittig-Still Rearrangement in Organic Synthesis.

    Rycek, Lukas; Hudlicky, Tomas


    This Review traces the discovery of the Wittig-Still rearrangement and its applications in organic synthesis. Its relationship to Wittig rearrangements is discussed along with detailed analysis of E/Z- and diastereoselectivity. Modifications of the products arising from the Wittig-Still rearrangement are reviewed in the context of increased complexity in intermediates potentially useful in target-oriented synthesis. Early applications of the Wittig-Still rearrangement to modifications of steroids are reviewed as are applications to various terpene and alkaloid natural product targets and miscellaneous compounds. To the best of our knowledge, the literature is covered through December 2016. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) Catalyzed Regio specific and Diastereoselective Reaction of Chiral N-(tert-Butanesulfinyl)ketimines and α,β-Unsaturated Trifluoromethyl Ketones%1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) Catalyzed Regio specific and Diastereoselective Reaction of Chiral N-(tert-Butanesulfinyl)ketimines and α,β-Unsaturated Trifluoromethyl Ketones

    张帆; 刘振江; 刘金涛


    The reaction of chiral N-(tert-butanesulfinyl)ketimines and α,β-unsaturated trifluorotuethyl ketones catalyzed by DBU was achieved under mild conditions. 1,2-Addition products, precursors of chiral trifluoromethylated 1,3-amino alcohols, were obtained diastereoselectively (dr value up to 95 : 5) in moderate yields (up to 76%). A possible catalytic cycle was proposed.

  3. Enantioselective Synthesis of Antiepileptic Drug: (--Levetiracetam—Synthetic Applications of the Versatile New Chiral N-Sulfinimine

    K. Chandra Babu


    Full Text Available We report an asymmetric synthesis of (--Levetiracetam (1 in six steps starting from versatile new chiral N-sulfinimine (3. The key step, stereoselective 1,2-addition of ethylmagnesium bromide (EtMgBr to chiral N-sulfinimine derived from (R-glyceraldehyde acetonide and (S-t-BSA, gave the corresponding sulfonamide (2 in high diastereoselectivity. Simultaneous deprotection and deacetylation followed by NaIO4 cleavage and reduction gave β-amino alcohol (6. Subsequent reactions yielded the targeted compound levetiracetam (1.

  4. Hyphenating the curtius rearrangement with Morita-Baylis-Hillman adducts: synthesis of biologically active acyloins and vicinal aminoalcohols

    Amarante, Giovanni W.; Cavallaro, Mayra; Coelho, Fernando, E-mail: coelho@iqm.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Lab. de Sintese de Produtos Naturais e Farmacos


    Using Morita-Baylis-Hillman adducts as substrates, the Curtius rearrangement was performed in a sequence that allowed the synthesis of several hydroxy-ketones (acyloins) with great structural diversity and in good overall yields. These acyloins in turn were easily transformed into 1,2-anti aminoalcohols through a highly diastereoselective reductive amination step. The synthetic utility of these approaches was exemplified by performing the syntheses of (+-)-bupropion, a drug used to treat the abstinence syndrome of smoker and (+-)-spisulosine, a potent anti-tumoral compound originally isolated from a marine source. (author)

  5. Exploring O-stannyl ketyl and acyl radical cyclizations for the synthesis of γ-lactone-fused benzopyrans and benzofurans.

    Santoso, Helen; Casana, Myriam I; Donner, Christopher D


    The synthesis of a series of γ-lactone-fused benzopyrans and benzofurans, analogues of the pyranonaphthoquinone antibiotics, is reported. Preparation of the heterocycles was achieved by either O-stannyl ketyl or acyl radical cyclization of benzaldehyde precursors followed by oxidation to give the pyrano- and furanobenzoquinone systems. The observed diastereoselectivity during O-stannyl ketyl radical cyclization is influenced by aromatic substitution ortho to the aldehyde, whilst acyl radical cyclization followed by stereoselective reduction of the resulting pyranones provides a complimentary approach to forming the required γ-lactone-fused benzopyran systems.

  6. Total synthesis, assignment of the relative and absolute stereochemistry, and structural reassignment of phostriecin (aka Sultriecin).

    Burke, Christopher P; Haq, Nadia; Boger, Dale L


    A total synthesis of phostriecin (2), previously known as sultriecin (1), its structural reassignment as a phosphate versus sulfate monoester, and the assignment of its relative and absolute stereochemistry are disclosed herein. Key elements of the work, which provided first the originally assigned sulfate monoester 1 and then the reassigned and renamed phosphate monoester 2, relied on diagnostic (1)H NMR spectroscopic properties of the natural product for the assignment of relative and absolute stereochemistry as well as the subsequent structural reassignment, and a convergent asymmetric total synthesis to provide the unequivocal authentic materials. Key steps of the synthetic approach include a Brown allylation for diastereoselective introduction of the C9 stereochemistry, an asymmetric CBS reduction to establish the lactone C5-stereochemistry, diastereoselective oxidative ring expansion of an alpha-hydroxyfuran to access the pyran lactone precursor, and single-step installation of the sensitive Z,Z,E-triene unit through a chelation-controlled cuprate addition with installation of the C11 stereochemistry. The approach allows ready access to analogues that can now be used to probe important structural features required for protein phosphatase 2A inhibition, the mechanism of action defined herein.

  7. Chiral-catalyst-based convergent synthesis of HIV protease inhibitor GRL-06579A.

    Mihara, Hisashi; Sohtome, Yoshihiro; Matsunaga, Shigeki; Shibasaki, Masakatsu


    Catalytic asymmetric synthesis of GRL-06579A (1), an HIV-1 protease inhibitor effective against multi-protease-inhibitor-resistant viruses, is described. A convergent strategy that utilizes heterobimetallic multifunctional catalysts developed in our group is a key feature of the synthesis. The chirality of the bicyclic tetrahydrofuran unit of 1 was introduced through Al-Li-bis(binaphthoxide) (ALB) catalyst-controlled Michael addition of dimethyl malonate to racemic 4-O-protected cyclopentenone. ALB afforded not only the trans adduct with up to 96% ee from a matched substrate through kinetic resolution, but also the cis adduct with 99% ee through a catalyst-controlled Michael addition to a mismatched substrate. The Michael addition to produce the unusual cis adduct is described in detail. The framework of the bicyclic tetrahydrofuran was constructed by an intramolecular oxy-Michael reaction. The amino alcohol unit was constructed by an La-Li3-tris(binaphthoxide) (LLB)-catalyzed diastereoselective nitroaldol reaction of N-Boc aldehyde (Boc = tert-butoxycarbonyl) derived from L-phenylalanine. LLB promoted the nitroaldol reaction without racemization of the chiral aldehyde to give the nitroaldol adduct in 85% yield and with 93:7 diastereoselectivity and over 99% ee.

  8. Synthesis of Bis-pyrrolizidine-Fused Dispiro-oxindole Analogues of Curcumin via One-Pot Azomethine Ylide Cycloaddition: Experimental and Computational Approach toward Regio- and Diastereoselection.

    Bharitkar, Yogesh P; Das, Mohua; Kumari, Neha; Kumari, M Padma; Hazra, Abhijit; Bhayye, Sagar S; Natarajan, Ramalingam; Shah, Siddharth; Chatterjee, Sourav; Mondal, Nirup B


    Curcumin has been transformed to racemic curcuminoids via an azomethine ylide cycloaddition reaction using isatin/acenaphthoquinone and proline as the reagents. The products were characterized by extensive 1D/2D NMR analysis and single-crystal X-ray crystallographic studies. The enantiomers of one racemic product were separated by HPLC on a Chiralcel OD-H column and were indeed confirmed by the CD spectra of the separated enantiomers.

  9. 非对映选择性合成威士忌内酯%Diastereoselective Synthesis of (±)-trans-Whisky Lactone

    胡国文; 吴鸣虎; 陈祖兴; 李焰; 杨桂春



  10. Synthesis of a chiral quaternary carbon center bearing a fluorine atom: enantio- and diastereoselective guanidine-catalyzed addition of fluorocarbon nucleophiles.

    Jiang, Zhiyong; Pan, Yuanhang; Zhao, Yujun; Ma, Ting; Lee, Richmond; Yang, Yuanyong; Huang, Kuo-Wei; Wong, Ming Wah; Tan, Choon-Hong


    The perfect combination: The title reaction provides adducts having quaternary carbon centers bearing a fluorine atom with high ee and d.r. values (see scheme). The mechanism and origin of stereoselectivity were elucidated by DFT calculations. The bifunctional mode of the guanidine catalysis was demonstrated in the transition states resulting from the DFT results.

  11. Periselectivity switch of acylketenes in cycloadditions with 1-azadienes: microwave-assisted diastereoselective domino three-component synthesis of α-spiro-δ-lactams.

    Presset, Marc; Coquerel, Yoann; Rodriguez, Jean


    The microwave-assisted Wolff rearrangement of cyclic 2-diazo-1,3-diketones in the presence of primary amines and α,β-unsaturated aldehydes provides a straightforward three-component stereoselective access to a variety of α-spiro-δ-lactams following an imination/Wolff rearrangement/[2 + 4] cycloaddition domino sequence. With aniline derivatives, a complementary aza-Wittig/Wolff rearrangement/[2 + 4] sequence was developed. These reactions feature an unprecedented reactivity of acylketenes as dienophiles in 6π electrocyclic processes.

  12. Total synthesis of the congested propellane alkaloid (-)-acutumine.

    Castle, Steven L


    The enantioselective total synthesis of (-)-acutumine is described. The synthetic strategy was inspired by the premise that the cyclohexenone ring could be derived from an aromatic precursor. After successful construction of a propellane model system, an initial attempt to prepare the spirocyclic subunit was thwarted by incorrect regioselectivity in a radical cyclization. A second-generation approach involving a radical-polar crossover reaction was successful, and the chemistry developed in the aforementioned model system was then applied to synthesize the natural product. Key reactions included a phenolic oxidation, a diastereoselective ketone allylation utilizing Nakamura's chiral allylzinc reagent, an anionic oxy-Cope rearrangement, an acid-promoted cyclization of a secondary amine onto an α,β-unsaturated ketal, and a regioselective methyl enol etherification of a 1,3-diketone.

  13. Α-amino-β-fluorocyclopropanecarboxylic acids as a new tool for drug development: synthesis of glutamic acid analogs and agonist activity towards metabotropic glutamate receptor 4.

    Lemonnier, Gérald; Lion, Cédric; Quirion, Jean-Charles; Pin, Jean-Philippe; Goudet, Cyril; Jubault, Philippe


    Herein we describe the diastereoselective synthesis of glutamic acid analogs and the evaluation of their agonist activity towards metabotropic glutamate receptor subtype 4 (mGluR4). These analogs are based on a monofluorinated cyclopropane core substituted with an α-aminoacid function. The potential of this new building block as a tool for the development of a novel class of drugs is demonstrated with racemic analog 11a that displayed the best agonist activity with an EC50 of 340 nM.

  14. Ethylene in Organic Synthesis. Repetitive Hydrovinylation of Alkenes for Highly Enantioselective Syntheses of Pseudopterosins

    Mans, Daniel J.; Cox, G. Adam; RajanBabu, T. V.


    In this report we highlight the significant potential of ethylene as a reagent for the introduction of a vinyl group with excellent stereoselectivity at three different stages in the synthesis of a broad class of natural products, best exemplified by syntheses of pseudopterosins. The late-stage applications of the asymmetric hydrovinylation reaction further illustrate the compatibility of the catalyst with complex functional groups. We also show that depending on the choice of the catalyst, it is possible to either enhance or even completely reverse the inherent diastereoselectivity in the reactions of advanced chiral intermediates. This should enable the synthesis of diastereomeric analogs of several classes of medicinally relevant compounds that are not readily accessible by the existing methods, which depend on ‘substrate-control’ for the installation of many of the chiral centers, especially in molecules of this class. PMID:21449569

  15. Some remarks on the two-electron atom

    Apostol, M


    New, approximate, two-electron wavefunctions are introduced for the two-electron atoms (cations), which account remarkably well for the ground-state energies and the lowest-excxited states (where available). A new scheme of electronic configurations is also proposed for the multi-electron atoms.

  16. Steiner versus Wittgenstein: Remarks on Differing Views of Mathematical Truth

    Charles SAYWARD


    Full Text Available Mark Steiner criticizes some remarks Wittgenstein makes about Gödel. Steiner takes Wittgenstein to be disputing a mathematical result. The paper argues that Wittgenstein does no such thing. The contrast between the realist and the demonstrativist concerning mathematical truth is examined. Wittgenstein is held to side with neither camp. Rather, his point is that a realist argument is inconclusive.

  17. Remarks on Nephrops norvegicus (L.) and its variety Meridionalis zariquiey

    Holthuis, L.B.


    In 1935 R. Zariquiey Cenarro published a paper in the Spanish language, in which he separated the specimens of Nephrops norvegicus occurring in the Mediterranean and the southern Atlantic Ocean as a separate variety meridionalis from the typical form of the northern Atlantic. In this paper he remark

  18. Discussant Remarks on Session: Statistical Aspects of Measuring the Internet

    Cottrell, Les


    These remarks will briefly summarize what we learn from the talks in this session, and add some more areas in Internet Measurement that may provide challenges for statisticians. It will also point out some reasons why statisticians may be interested in working in this area.

  19. A Remarkable Recent Transition in the Solar Dynamo

    de Jager, C.; Akasofu, S.-I.; Duhau, S.; Livingston, W.C.; Nieuwenhuijzen, H.; Potgieter, M.S.


    We summarize the major aspects of the remarkable, fairly long lasting period(∼ 2005 to ∼ 2010) of low solar activity, that we will call the Transition. It is the transitionalstage between the Grand Maximum of the 20th century and a forthcoming (most probablyRegular) episode of solar activity. The va

  20. Initial remarks on Sur la genèse

    G. M. Goshgarian


    Full Text Available G. M. Goshgarian describes historical and theoretical context in whichAlthusser’s note On Genesis has been written. Goshgarian indicated theoreticalsources of althusserian remarks in the theme of genesis. He invokes – next to Marx– such names as Montaigne or Spinoza.

  1. Concluding remarks: Faraday Discussion on chemistry in the urban atmosphere.

    Jimenez, Jose L


    This article summarises the Concluding remarks from the Faraday Discussion on Chemistry in the Urban Atmosphere. The following themes are addressed: (a) new results that inform our understanding of the evolving sources and composition of the urban atmosphere ("News"); (b) results that identify gaps in our understanding that necessitate further work ("Gaps");

  2. Remarkable movements of an American crocodile (Crocodylus acutus) in Florida

    Cherkiss, Michael S.; Mazzotti, Frank J.; Hord, Lindsey; Aldecoa, Mario


    Here we present the remarkable movements of an individual Crocodylus acutus (American Crocodile) over a 14-year period. The crocodile was originally marked in Homestead, FL as a young-of-the-year in 1999, and was later recaptured multiple times more than 388 km away along the southwest coast of Florida. After several relocations and numerous sightings, this individual who has become known as Yellow Number 1 was found back within the same canal system in which it was first captured.

  3. Remarks on a benchmark nonlinear constrained optimization problem

    Luo Yazhong; Lei Yongjun; Tang Guojin


    Remarks on a benchmark nonlinear constrained optimization problem are made. Due to a citation error, two absolutely different results for the benchmark problem are obtained by independent researchers. Parallel simulated annealing using simplex method is employed in our study to solve the benchmark nonlinear constrained problem with mistaken formula and the best-known solution is obtained, whose optimality is testified by the Kuhn-Tucker conditions.

  4. Average of Distribution and Remarks on Box-Splines

    LI Yue-sheng


    A class of generalized moving average operators is introduced, and the integral representations of an average function are provided. It has been shown that the average of Dirac δ-distribution is just the well known box-spline. Some remarks on box-splines, such as their smoothness and the corresponding partition of unity, are made. The factorization of average operators is derived. Then, the subdivision algorithm for efficient computing of box-splines and their linear combinations follows.

  5. Organozinc reagents in DMSO solvent: remarkable promotion of SN2' reaction for allene synthesis.

    Kobayashi, Koji; Naka, Hiroshi; Wheatley, Andrew E H; Kondo, Yoshinori


    The S N2' reaction of propragyl mesylates with organozinc reagents was dramatically improved in DMSO solvent, and the stereoselective conversion of chiral substrates was successfully achieved using LiCl-free diorganozinc without the loss of optical purity.


    Constantin MANEA


    Full Text Available The aim of the present paper is to briefly illustrate and assess the main uses of intensifiers and intensification in English and Romanian, trying to hint at the complexity of the phenomenon in the two languages, while sketchily suggesting ways to improve the teaching and learning activities in Romanian schools, as well as much of the activity of translators in this country. The authors’s illustrative treatment tackles the broader sphere of intensification, not only such intensifiers as very, terribly, awfully, really, definitely, kind of. The main subsections of the paper deal, respectively, with semantic aspects, word formation, syntactic aspects, stylistic issues, and a few remarks on usage.

  7. Remarkable Computing - the Challenge of Designing for the Home

    Petersen, Marianne Graves


    The vision of ubiquitous computing is floating into the domain of the household, despite arguments that lessons from design of workplace artefacts cannot be blindly transferred into the domain of the household. This paper discusses why the ideal of unremarkable or ubiquitous computing is too narrow...... with respect to the household. It points out how understanding technology use, is a matter of looking into the process of use and on how the specific context of the home, in several ways, call for technology to be remarkable rather than unremarkable....

  8. Remarks on different reviews of Chinese character recognition

    TANG Yuanyan


    This paper gives an introduction and remarks on two review papers for Chinese character recognition.One review is made by Chinese authors,another is from American scientists.They investigate Chinese character from different language environments;they do the research from different points of view.Thus,a more comprehensive view on Chinese character recognition,which is an important branch of pattern recognition,can be provided to the readers.Meantime,one article pays attention to online process,and other paper deals with offiine recognition,which complement each other.

  9. Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea)

    Pérez-Losada, Marcos; Høeg, Jens Thorvald; Crandall, Keith A


    analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from...... the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. Results To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2...

  10. Remark on non-Abelian classical kinetic theory

    Laine, Mikko; Laine, Mikko; Manuel, Cristina


    It is known that non-Abelian classical kinetic theory reproduces the Hard Thermal/Dense Loop (HTL/HDL) effective action of QCD, obtained after integrating out the hardest momentum scales from the system, as well as the first higher dimensional operator beyond the HTL/HDL level. We discuss here its applicability at still higher orders, by comparing the exact classical effective action obtained in the static limit, with the 1-loop quantum effective potential. We remark that while correct types of operators arise, the classical colour algebra reproduces correctly the prefactor of the 4-point function $tr A_0^4$ only for matter in asymptotically high dimensional colour representations.

  11. A Few Remarks About Formal Development of Secure Systems

    Jaeger, Eric; 10.1109/HASE.2008.49


    Formal methods provide remarkable tools allowing for high levels of confidence in the correctness of developments. Their use is therefore encouraged, when not required, for the development of systems in which safety or security is mandatory. But effectively specifying a secure system or deriving a secure implementation can be tricky. We propose a review of some classical `gotchas' and other possible sources of concerns with the objective to improve the confidence in formal developments, or at least to better assess the actual confidence level.

  12. Nationwide Genomic Study in Denmark Reveals Remarkable Population Homogeneity

    Athanasiadis, Georgios; Cheng, Jade Y; Vilhjálmsson, Bjarni J;


    polygenic predictions of phenotypic traits in adolescents. We observed remarkable homogeneity across different geographic regions, although we could still detect weak signals of genetic structure reflecting the history of the country. Denmark presented genomic affinity with primarily neighboring countries...... with overall resemblance of decreasing weight from Britain, Sweden, Norway, Germany and France. A Polish admixture signal was detected in Zealand and Funen and our date estimates coincided with historical evidence of Wend settlements in the south of Denmark. We also observed considerably diverse demographic...

  13. Stereocontrolled Synthesis of a Potential Transition-State Inhibitor of the Salicylate Synthase MbtI from Mycobacterium tuberculosis.

    Liu, Zheng; Liu, Feng; Aldrich, Courtney C


    Mycobactins are small-molecule iron chelators (siderophores) produced by Mycobacterium tuberculosis (Mtb) for iron mobilization. The bifunctional salicylate synthase MbtI catalyzes the first step of mycobactin biosynthesis through the conversion of the primary metabolite chorismate into salicylic acid via isochorismate. We report the design, synthesis, and biochemical evaluation of an inhibitor based on the putative transition state (TS) for the isochorismatase partial reaction of MbtI. The inhibitor mimics the hypothesized charge buildup at C-4 of chorismate in the TS as well as C-O bond formation at C-6. Another important design element of the inhibitor is replacement of the labile pyruvate side chain in chorismate with a stable C-linked propionate isostere. We developed a stereocontrolled synthesis of the highly functionalized cyclohexene inhibitor that features an asymmetric aldol reaction using a titanium enolate, diastereoselective Grignard addition to a tert-butanesulfinyl aldimine, and ring closing olefin metathesis as key steps.

  14. Towards a description of interactive psychoinformation systems preliminary remarks

    Juriev, D V


    An approach to description of interactive psychoinformation systems, based on the concept of "virtualization" and essentially using the technique of the "secondary image synthesis" (adap-org/9409002), is sketched. The article has a rather discussional character and maybe considered as a comment to some statements of the introduction to the author's paper "Complex projective geometry and quantum projective field theory" (Theor. Math. Phys., 1994).

  15. Escaping the flybottle: solipsism and method in Wittgenstein's Philosophical Remarks

    Jônadas Techio


    Full Text Available The paper supports a dialectical interpretation of Wittgenstein's method focusing on the analysis of the conditions of experience presented in his Philosophical Remarks. By means of a close reading of some key passages dealing with solipsism I will try to lay bare their self-subverting character: the fact that they amount to miniature dialectical exercises offering specific directions to pass from particular pieces of disguised nonsense to corresponding pieces of patent nonsense. Yet, in order to follow those directions one needs to allow oneself to become simultaneously tempted by and suspicious of their all-too-evident "metaphysical tone" - a tone which, as we shall see, is particularly manifest in those claims purporting to state what can or cannot be the case, and, still more particularly, those purporting to state what can or cannot be done in language or thought, thus leading to the view that there are some (determinate things which are ineffable or unthinkable. I conclude by suggesting that in writing those remarks Wittgenstein was still moved by an ethical project, which gets conspicuously displayed in these reiterations of his attempts to cure the readers (and himself from some of the temptations expressed by solipsism.

  16. Remarkable symmetries in the Milky Way disk's magnetic field

    Kronberg, Philipp P


    We report new, remarkably coherent patterns of Faraday rotation (RM) at $b \\lesssim 15 \\deg$ in the inner Galactic plane, using an expanded extragalactic source RM compilation of unprecedented average accuracy. The patterns, relevant to RM pathlengths toward the inner Galactic disk, clearly indicate a global disk magnetic field structure, with remarkable reflection symmetry in RM. Sharply defined RM($l$) features replicate with the opposite sign on opposite sides of the Galactic center, confirming the bi-symmetric magnetic field pattern {\\it inward} of the Sagittarius-Carina arm originally found by Simard-Normandin and Kronberg (1979). The prevailing magnetic field points to $l = 79 \\pm 2\\deg$, very close to the general spiral arm direction. Additional sharp RM sign reversals in $b$, just below the Galactic plane, are consistent with an A0 galactic dynamo configuration. At all ``outer'' longitudes, there are no large scale RM sign reversals either {\\it at} the Galactic plane or near to it. The outer Galactic ...

  17. Practical remarks on the heart rate and saturation measurement methodology

    Kowal, M.; Kubal, S.; Piotrowski, P.; Staniec, K.


    A surface reflection-based method for measuring heart rate and saturation has been introduced as one having a significant advantage over legacy methods in that it lends itself for use in special applications such as those where a person’s mobility is of prime importance (e.g. during a miner’s work) and excluding the use of traditional clips. Then, a complete ATmega1281-based microcontroller platform has been described for performing computational tasks of signal processing and wireless transmission. In the next section remarks have been provided regarding the basic signal processing rules beginning with raw voltage samples of converted optical signals, their acquisition, storage and smoothing. This chapter ends with practical remarks demonstrating an exponential dependence between the minimum measurable heart rate and the readout resolution at different sampling frequencies for different cases of averaging depth (in bits). The following section is devoted strictly to the heart rate and hemoglobin oxygenation (saturation) measurement with the use of the presented platform, referenced to measurements obtained with a stationary certified pulsoxymeter.

  18. Stereoselective synthesis of chiral sulfilimines from N-mesyloxycarbamates: metal-nitrenes versus metal-nitrenoids species.

    Lebel, Hélène; Piras, Henri


    The synthesis of a variety of chiral sulfilimines and sulfoximines is described. The amination of thioethers with a chiral N-mesyloxycarbamate was achieved in high yields and stereoselectivities using Rh2[(S)-nttl]4 as catalyst in the presence of 4-dimethylaminopyridine (DMAP) and a pyridinium salt, such as bis(DMAP)CH2Cl2 or a viologen salt. These additives proved instrumental to enhance both the yield and the stereochemical discrimination of the reaction. Mechanistic studies and control experiments have elucidated the role of these additives. DMAP served as an apical ligand for the rhodium catalyst: an X-ray crystal structure of the (DMAP)2·[Rh2{(S)-nttl}4] complex was obtained. This complex displayed a lower and irreversible redox potential. Control experiments with preformed Rh(II)-Rh(III) complex suggested such a catalytically active species in the thioether amination process. Diastereoselectivities were influenced by the sulfonyloxy leaving group, ruling out the possibility of a common metal nitrene species and instead suggesting a rhodium-nitrenoid complex. It is believed that the bispyridinium salt played the role of a phase transfer catalyst, influencing both the yield and the diastereoselectivity of the reaction.

  19. A Remark on Contact Hypersurfaces of a Complex Hyperbolic Space



    A differentiable manifold is said to be contact if it admits a linear functional f on the tangent bundle satisfying f∧ (df)n-1≠0.This remark obtain the following the classification:Let M be a complete connected contact hyper-surface of CH2(-4),then M is congruent to one of the following:(i) A tube of redius r>0 around a totally geodesic,totally real hyperbolic space form H2(-1);(ii)A tube of radius r>0 around a totally geodesic complex hyperbolic space form CH1(-4);(iii)A geodesic hypersphere of radius r>0,or(iv)A horosphere.

  20. Charles Hard Townes: Remarkable Scientist and Inspiring Teacher

    Goldsmith, P. F.


    Charles Townes is renowned for his work elucidating the structure of molecules through microwave spectroscopy and for his invention of the maser and the laser. He also had a lifelong interest in astronomy, and in the later portion of his remarkable and long career devoted himself to astronomical research, pioneering the study of molecules in interstellar space and the development of infrared spectroscopy, first from the ground and then from airborne facilities. His interest in high angular resolution, as well as high spectral resolution observations, led to development of the first infrared spatial interferometer employing coherent signal processing techniques. In this short review I will only touch on some of Townes' many scientific contributions, concentrating on astronomy, and will also give some personal thoughts about how he inspired students in their research, helping to make the "Townes Group" at the University of California, Berkeley, an ideal environment in which to start a career in research.

  1. Remarkable NO oxidation on single supported platinum atoms.

    Narula, Chaitanya K; Allard, Lawrence F; Stocks, G M; Moses-DeBusk, Melanie


    Our first-principles density functional theoretical modeling suggests that NO oxidation is feasible on fully oxidized single θ-Al2O3 supported platinum atoms via a modified Langmuir-Hinshelwood pathway. This is in contrast to the known decrease in NO oxidation activity of supported platinum with decreasing Pt particle size believed to be due to increased platinum oxidation. In order to validate our theoretical study, we evaluated single θ-Al2O3 supported platinum atoms and found them to exhibit remarkable NO oxidation activity. A comparison of turnover frequencies (TOF) of single supported Pt atoms with those of platinum particles for NO oxidation shows that single supported Pt atoms are as active as fully formed platinum particles. Thus, the overall picture of NO oxidation on supported Pt is that NO oxidation activity decreases with decreasing Pt particle size but accelerates when Pt is present only as single atoms.

  2. The Social Interplay of Disciplinarity and Interdisciplinarity. Some Introductory Remarks

    Reinhold Hedtke


    Full Text Available Social Science Education as a subject field in schools is an intrinsic pluridisciplinary feature, whatever disciplines are included, however it may be organised and wherever it may be institutionalised. Civic education, economic education, social education and historical education each comprise several academic disciplines even if they are thought to be completely independent subjects. From the start on, disciplinarity and interdisciplinarity are on the agenda for any subject related to social science education and are one of its main problems. For these introductory remarks interdisciplinarity can be simply defined as relating two or more academic disciplines or school subjects to each other if this is done in a purposeful, systematic, explicit and reflective way. The overarching goal is to improve education that is to enhance students' understandings of the worlds and their abilities to act within and towards them. A relationship between disciplines or subjects which misses one or more of the four characteristics can be called pluridisciplinary or multidisciplinary (cf. Audigier 2006. In the following I first want to discuss some aspects of disciplinarity and interdisciplinarity at schools and at universities and the weakness of interdisciplinarity. I sketch some social science based ideas on the interrelationship between the subject structure of the academic world and the world of schools (3. and of some tendency to commonalities or even unification of social sciences and related competencies (4.. I conclude with some remarks on different kinds of knowledge (5.. Last but not least, I'll give an overview on the papers in this issue of the Journal of Social Science Education (6..

  3. Petasis-type reactions for the synthesis of substituted pyrrolidin-2-ones

    Wu, Peng; Clausen, Mads Hartvig; Nielsen, Thomas Eiland


    for the formation of substituted pyrrolidin-2-ones. Only few studies on the nucleoph ic addition of organoboronic acids to N -acyliminium ions have been reported. Herein, we disclose our re cent efforts for the synthesis of substituted pyrro lidin- 2-ones through Lewis-acid-mediated Petasis-type rea ctions....... By implementing a reductive cyclization reaction, linear L -malic acid derivatives were rapidly converted into cyclic N -acyliminium ions. Under the optimized conditions, entailing the use of HFIP as solvent, both electron-rich and electron-deficient boronic acids were successfully added to a range of cyclic N...... -acyliminium ions, typically with excellent diastereoselectivity with electron-deficient boroni c acids....

  4. Synthesis and biological activity of pyrrole analogues of combretastatin A-4.

    Jung, Eun-Kyung; Leung, Euphemia; Barker, David


    A series of pyrrole analogues of combretastatin (CA-4) were synthesized and tested for their anti-proliferative activity. The highly diastereoselective acyl-Claisen rearrangement was used to provide 2,3-syn disubstituted morpholine amides which were used as precursors for the various analogues. This synthesis allows for the preparation of 1,2- and 2,3-diaryl-1H-pyrroles which are both geometrically similar to CA-4. These pyrrolic analogues were tested for their anti-proliferative activity against two human cell lines, K562 and MDA-MB-231 with 2,3-diaryl-1H-pyrrole 35 exhibiting the most potent activity with IC50 value of 0.07μM against MDA-MB-231 cell line.

  5. Design and Stereoselective Preparation of a New Class of Chiral Olefin Metathesis Catalysts and Application to Enantioselective Synthesis of Quebrachamine: Catalyst Development Inspired by Natural Product Synthesis

    Sattely, Elizabeth S.; Meek, Simon J.; Malcolmson, Steven J.; Schrock, Richard R.; Hoveyda, Amir H.


    A total synthesis of the Aspidosperma alkaloid quebrachamine in racemic form is first described. A key catalytic ring-closing metathesis of an achiral triene is used to establish the all-carbon quaternary stereogenic center and the tetracyclic structure of the natural product; the catalytic transformation proceeds with reasonable efficiency through the use of existing achiral Ru or Mo catalysts. Ru- or Mo-based chiral olefin metathesis catalysts have proven to be inefficient and entirely nonselective in cases where the desired product is observed. In the present study, the synthesis route thus serves as a platform for the discovery of new olefin metathesis catalysts that allow for efficient completion of an enantioselective synthesis of quebrachamine. Accordingly, on the basis of mechanistic principles, stereogenic-at-Mo complexes bearing only monodentate ligands have been designed. The new catalysts provide significantly higher levels of activity than observed with the previously reported Ru- or Mo-based complexes. Enantiomerically enriched chiral alkylidenes are generated through diastereoselective reactions involving achiral Mo-based bispyrrolides and enantiomerically pure silyl-protected binaphthols. Such chiral catalysts initiate the key enantioselective ring-closing metathesis step in the total synthesis of quebrachamine efficiently (1 mol % loading, 22 °C, 1 h, >98% conversion, 84% yield) and with high selectivity (98:2 er, 96% ee). PMID:19113867

  6. Rh(III)-Catalyzed Diastereoselective Annulation of Amides with Quinone Monoacetals: Access to Bridged Nine-Membered Heterocycles via C-H Activation.

    Yang, Wei; Dong, Jinhuan; Wang, Jingyi; Xu, Xianxiu


    An unprecedented Rh(III)-catalyzed annulation of various benzamides and acrylamides with quinone monoacetals was developed for the facile and efficient one-pot synthesis of bridged nine-membered benzo[c]azonine-1,5(2H)-diones and 2-azabicyclo[4.3.1]dec-4-ene-3,8-diones. It is the first example of synthesis of nine-membered heterocycles through Rh(III)-catalyzed C-H bond functionalization, and both aryl and vinyl C-H bonds are tolerant in this reaction. A plausible mechanism is proposed on the basis of control experiments.

  7. Microfabricated pseudocapacitors using Ni(OH)2 electrodes exhibit remarkable volumetric capacitance and energy density

    Kurra, Narendra


    Metal hydroxide based microfabricated pseudocapacitors with impressive volumetric stack capacitance and energy density are demonstrated. A combination of top-down photolithographic process and bottom-up chemical synthesis is employed to fabricate the micro-pseudocapacitors (μ-pseudocapacitors). The resulting Ni(OH)2-based devices show several excellent characteristics including high-rate redox activity up to 500 V s-1 and an areal cell capacitance of 16 mF cm-2 corresponding to a volumetric stack capacitance of 325 F cm-3. This volumetric capacitance is two-fold higher than carbon and metal oxide based μ-supercapacitors with interdigitated electrode architecture. Furthermore, these μ-pseudocapacitors show a maximum energy density of 21 mWh cm-3, which is superior to the Li-based thin film batteries. The heterogeneous growth of Ni(OH)2 over the Ni surface during the chemical bath deposition is found to be the key parameter in the formation of uniform monolithic Ni(OH)2 mesoporous nanosheets with vertical orientation, responsible for the remarkable properties of the fabricated devices. Additionally, functional tandem configurations of the μ-pseudocapacitors are shown to be capable of powering a light-emitting diode.

  8. Remarks on the fission barriers of super-heavy nuclei

    Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Heinz, S.; Mann, R.; Maurer, J.; Muenzenberg, G.; Barth, W.; Dahl, L.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Runke, J.; Scheidenberger, C.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Antalic, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Eberhardt, K.; Thoerle-Pospiech, P.; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Grzywacz, R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States); Hamilton, J.H. [Vanderbilt University, Department of Physics and Astronomy, Nashville, TN (United States); Henderson, R.A.; Kenneally, J.M.; Moody, K.J.; Shaughnessy, D.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Miernik, K. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Warsaw, Warsaw (Poland); Miller, D. [University of Tennessee, Knoxville, TN (United States); Morita, K. [RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama (Japan); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Roberto, J.B.; Rykaczewski, K.P. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland)


    Shell-correction energies of super-heavy nuclei are approximated by using Q{sub α} values of measured decay chains. Five decay chains were analyzed, which start at the isotopes {sup 285}Fl, {sup 294}118, {sup 291}Lv, {sup 292}Lv and {sup 293}Lv. The data are compared with predictions of macroscopic-microscopic models. Fission barriers are estimated that can be used to eliminate uncertainties in partial fission half-lives and in calculations of evaporation-residue cross-sections. In that calculations, fission probability of the compound nucleus is a major factor contributing to the total cross-section. The data also provide constraints on the cross-sections of capture and quasi-fission in the entrance channel of the fusion reaction. Arguments are presented that fusion reactions for synthesis of isotopes of elements 118 and 120 may have higher cross-sections than assumed so far. (orig.)

  9. Remarkable reduction of thermal conductivity in phosphorene phononic crystal.

    Xu, Wen; Zhang, Gang


    Phosphorene has received much attention due to its interesting physical and chemical properties, and its potential applications such as thermoelectricity. In thermoelectric applications, low thermal conductivity is essential for achieving a high figure of merit. In this work, we propose to reduce the thermal conductivity of phosphorene by adopting the phononic crystal structure, phosphorene nanomesh. With equilibrium molecular dynamics simulations, we find that the thermal conductivity is remarkably reduced in the phononic crystal. Our analysis shows that the reduction is due to the depressed phonon group velocities induced by Brillouin zone folding, and the reduced phonon lifetimes in the phononic crystal. Interestingly, it is found that the anisotropy ratio of thermal conductivity could be tuned by the 'non-square' pores in the phononic crystal, as the phonon group velocities in the direction with larger projection of pores is more severely suppressed, leading to greater reduction of thermal conductivity in this direction. Our work provides deep insight into thermal transport in phononic crystals and proposes a new strategy to reduce the thermal conductivity of monolayer phosphorene.

  10. A Remarkable Recent Transition in the Solar Dynamo

    de Jager, C.; Akasofu, S.-I.; Duhau, S.; Livingston, W. C.; Nieuwenhuijzen, H.; Potgieter, M. S.


    We summarize the major aspects of the remarkable, fairly long lasting period ( ˜ 2005 to ˜ 2010) of low solar activity, that we will call the Transition. It is the transitional stage between the Grand Maximum of the 20th century and a forthcoming (most probably Regular) episode of solar activity. The various kinds of activity in the functioning of the equatorial components of the solar dynamo before and during the Transition are summarized. While the behavior of unipolar magnetic regions and their rest-latitudes already gave very early indications - mid 20th century - of the forthcoming Transition, more such indications became available around 1995 and the main part of it occurred between 2005 and 2010. Some of the inferences are discussed. We submit the hypothesis that the solar tachocline undergoes pulsations and we present some helioseismic evidences. In that scenario we find that its equatorial part has moved downward over a fairly small semi-amplitude ( ˜ 0.03 solar radii) during the time of the Transition. There are several indications, apart from this `pulsation', that the tachocline may even be pulsating with still smaller amplitudes in more modes. We speculate about the physical mechanism(s).

  11. Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea

    Crandall Keith A


    Full Text Available Abstract Background The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta. Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups. Results To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305, 28S rRNA (2,402, Histone H3 (328] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup and 12 Malacostraca and 10 Copepoda (outgroup. Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica. Conclusion Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite.

  12. Shared Voyage: Learning and Unlearning from Remarkable Projects

    Laufer, Alexander; Post, Todd; Hoffman, Edward J.


    Shared Voyage is about four remarkable projects: the Advanced Composition Explorer (NASA), the Joint Air-to-Surface Standoff Missile (U.S. Air Force), the Pathfinder Solar-Powered Airplane (NASA), and the Advanced Medium Range Air-to-Air Missile (U.S.Air Force). Each project is presented as a case study comprised of stories collected from key members of the project teams. The stories found in the book are included with the purpose of providing an effective learning source for project management, encouraging the unlearning of outdated project management concepts, and enhancing awareness of the contexts surrounding different projects. Significantly different from project concepts found in most project management literature, Shared Voyage highlights concepts like a will to win, a results-oriented focus, and collaboration through trust. All four project teams researched in this study applied similar concepts; however, they applied them differently, tailoring them to fit the context of their own particular projects. It is clear that the one best way approach which is still the prevailing paradigm in project management literature should be replaced by a new paradigm: Even though general project management principles exist, their successful application depends on the specifics of the situation.

  13. Synthesis of helical and supplementary chirally doped PMO materials. Suitable catalysts for asymmetric synthesis.

    García-Muñoz, Rafael A; Morales, Victoria; Linares, María; Rico-Oller, Beatriz


    Exciting helical mesoporous organosilicas including supplementary chirally doped moieties into their spiral walls were one-pot successfully synthesized with good structural order for, to the best of our knowledge, the first time. This one-step direct synthesis of helical chirally doped periodic mesoporous organosilica (PMO) materials was carried out by combination of a tartrate-based bis-organosilicon precursor with tetraethyl orthosilicate (TEOS) and two surfactants, cetyltrimethylammonium bromide and perfluoroctanoic acid (CTAB and PFOA). For comparison purposes, a conventional two-step postsynthetic grafting methodology was carried out. In this method, the chiral tartrate-based moieties were grafted onto the helical silica mesoporous materials previously prepared by the dual-templating approach (CTAB and PFOA). The chirally doped materials prepared by both methodologies exhibited helical structure and high BET surface area, pore size distributions, and total pore volume in the range of mesopores. Solid-state (13)C and (29)Si MAS NMR experiments confirmed the presence of the chiral organic precursor in the silica wall covalently bonded to silicon atoms. Nevertheless, one-pot direct synthesis led to a greater control of surface properties and presented larger incorporation of organic species compared with the two-step postsynthetic methodology. To further prove the potential feasibility of these materials in enantiomeric applications, Mannich diastereoselective asymmetric synthesis was chosen as catalytic test. In the case of the one-pot PMO material, the rigidity of the chiral ligand backbone provided by its integration into the inorganic helical wall in combination with the steric impediments supplied by the twisted geometry led to the reagents to adopt specific orientations. These geometrical constrictions resulted in an outstanding diastereomeric induction toward the preferred enantiomer.

  14. Asymmetric synthesis of (+)-hypusine.

    Jain, R P; Albrecht, B K; DeMong, D E; Williams, R M


    Wittig reaction of (triphenylphosphoranylidene)acetonitrile with the lactone carbonyl of (5R,6S)-4-(benzyloxycarbonyl)-5,6-diphenyl-2,3,5,6-tetrahydro-4H-1,4-oxazin-2-one (3) and subsequent reduction generates morpholinylethylamine dihydrochloride (5) in quantitative yield and with excellent diastereoselectivity. Compound 5 was readily converted into hypusine dihydrochloride (1.2HCl) in overall 53% yield. [reaction: see text

  15. A remarkable climate warming hiatus over Northeast China since 1998

    Sun, Xiubao; Ren, Guoyu; Ren, Yuyu; Fang, Yihe; Liu, Yulian; Xue, Xiaoying; Zhang, Panfeng


    Characteristics and causes of global warming hiatus (GWH) phenomenon have received much attention in recent years. Monthly mean data of land surface air maximum temperature (Tmax), minimum temperature (Tmin), and mean temperature (Tmean) of 118 national stations since 1951 in Northeast China are used in this paper to analyze the changes of land surface air temperature in recent 64 years with an emphasis on the GWH period. The results show that (1) from 1951 to 2014, the warming trends of Tmax, Tmin, and Tmean are 0.20, 0.42, and 0.34 °C/decade respectively for the whole area, with the warming rate of Tmin about two times of Tmax, and the upward trend of Tmean obviously higher than mainland China and global averages; (2) in the period 1998-2014, the annual mean temperature consistently exhibits a cooling phenomenon in Northeast China, and the trends of Tmax, Tmin, and Tmean are -0.36, -0.14, and -0.28 °C/decade respectively; (3) in the GWH period, seasonal mean cooling mainly occurs in northern winter (DJF) and spring (MAM), but northern summer (JJA) and autumn (SON) still experience a warming, implying that the annual mean temperature decrease is controlled by the remarkable cooling of winter and spring; (4) compared to the global and mainland China averages, the hiatus phenomenon is more evident in Northeast China, and the cooling trends are more obvious in the cold season; (5) the Northeast China cooling trend occurs under the circulation background of the negative phase Arctic Oscillation (AO), and it is also closely related to strengthening of the Siberia High (SH) and the East Asian Trough (EAT), and the stronger East Asian winter monsoon (EAWM) over the GWH period.

  16. Remarkable increase in fluoroquinolone-resistant Mycoplasma genitalium in Japan.

    Kikuchi, Mina; Ito, Shin; Yasuda, Mitsuru; Tsuchiya, Tomohiro; Hatazaki, Kyoko; Takanashi, Masaki; Ezaki, Takayuki; Deguchi, Takashi


    We determined the prevalence of macrolide and fluoroquinolone resistance-associated mutations in Mycoplasma genitalium DNA specimens from men with non-gonococcal urethritis (NGU) and analysed their effects on antibiotic treatments of M. genitalium infections. In this retrospective study, we examined antibiotic resistance-associated mutations in the 23S rRNA, gyrA and parC genes of M. genitalium and the association of the mutations with microbiological outcomes of antibiotic treatments in men with M. genitalium-positive NGU. No macrolide resistance-associated mutations in the 23S rRNA gene were observed in 27 M. genitalium DNA specimens in 2011 and in 24 in 2012. However, 5 of 17 in 2013 had 23S rRNA mutations. Three of 15 in 2011, 6 of 19 in 2012 and 8 of 17 in 2013 had fluoroquinolone resistance-associated alterations in ParC. Three in 2013 had both the antibiotic resistance-associated alterations coincidentally. In two men with M. genitalium harbouring 23S rRNA mutations, the mycoplasma persisted after treatment with a regimen of 2 g of extended-release azithromycin (AZM-SR) once daily for 1 day. All nine men with mycoplasma harbouring ParC alterations were microbiologically cured with a regimen of 100 mg of sitafloxacin twice daily for 7 days. Macrolide- or fluoroquinolone-resistant M. genitalium appears to be increasing, and the increase in fluoroquinolone-resistant mycoplasmas is especially remarkable in Japan. Mycoplasmas harbouring 23S rRNA mutations would be resistant to the AZM-SR regimen, but those harbouring ParC alterations would still be susceptible to the sitafloxacin regimen. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail:

  17. Plants: Emerging as Nanofactories towards Facile Route in Synthesis of Nanoparticles

    Baker, Syed; Rakshith, Devaraju; Kavitha, Kumara Shanthamma; Santosh, Parthasarathy; Kavitha, Holalu Umapathy; Rao, Yashavantha; Satish, Sreedharamurthy


    Plant mediated nanoparticles’ synthesis has led to a remarkable progress via unfolding a green synthesis protocol towards nanoparticles’ synthesis. It seems to have drawn quite an unequivocal attention with a view of reformulating the novel strategies as alternatives for popular conventional methods. Hence, the present review summarizes the literature reported thus far and envisions towards plants as emerging sources of nanofactories. PMID:24163802

  18. Plants: Emerging as Nanofactories towards Facile Route in Synthesis of Nanoparticles

    Sreedharamurthy Satish


    Full Text Available Plant mediated nanoparticles’ synthesis has led to a remarkable progress via unfolding a green synthesis protocol towards nanoparticles’ synthesis. It seems to have drawn quite an unequivocal attention with a view of reformulating the novel strategies as alternatives for popular conventional methods. Hence, the present review summarizes the literature reported thus far and envisions towards plants as emerging sources of nanofactories.

  19. Tandem catalysis in domino olefin cross-metathesis/intramolecular oxa-conjugate cyclization: concise synthesis of 2,6-cis-substituted tetrahydropyran derivatives.

    Fuwa, Haruhiko; Noguchi, Takuma; Noto, Kenkichi; Sasaki, Makoto


    Herein, we describe the concise synthesis of 2,6-cis-substituted tetrahydropyran derivatives based on a domino olefin cross-metathesis/intramolecular oxa-conjugate cyclization (CM/IOCC) reaction. We have found that the domino CM/IOCC of δ-hydroxy olefins with α,β-unsaturated carbonyl compounds (e.g., trans-crotonaldehyde or N-acryloyl-2,5-dimethylpyrrole) could be efficiently achieved in the presence of the second-generation Hoveyda-Grubbs catalyst under elevated temperature conditions, directly affording 2,6-cis-substituted tetrahydropyrans in excellent yields with synthetically useful diastereoselectivity ("auto-tandem catalysis"). In addition, we have found that the domino CM/IOCC of δ-hydroxy olefins with α,β-unsaturated carbonyl compounds could be achieved simply by performing CM in the presence of a Brønsted acid in CH(2)Cl(2) at 25-35 °C, which delivered 2,6-cis-substituted tetrahydropyrans in good yields with excellent diastereoselectivity ("orthogonal-tandem catalysis"). To understand the mechanism of auto-tandem catalysis in the domino CM/IOCC reaction, we have investigated the role of ruthenium hydride complexes in the IOCC of a ζ-hydroxy α,β-unsaturated ketone as a model case.

  20. One-pot synthesis of enantiomerically pure N-protected allylic amines from N-protected α-amino esters

    Silveira-Dorta, Gastón; Álvarez-Méndez, Sergio J; Martín, Víctor S


    Summary An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction–olefination process. The sequential reduction with DIBAL-H at −78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate the intermediate aldehyde. This circumvents the problem of instability of the aldehydes. The method tolerates well both Wittig and Horner–Wadsworth–Emmons organophosphorus reagents. A better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine and threonine derivatives. PMID:27340486

  1. Synthesis of Aromatic Retinoids and Curcuminoids and Evaluation of their Antiproliferative, Antiradical, and Anti‐inflammatory Activities

    Morzycki, Jacek W.; Rárová, Lucie; Grúz, Jiři; Sawczuk, Tomasz; Kiełczewska, Urszula; Siergiejczyk, Leszek


    Abstract Natural retinoids and curcuminoids are known for their broad spectrum of biological properties, such as antioxidant, anti‐inflammatory, antitumor, and so forth. In this work, a convenient synthesis of aromatic retinoids and curcuminoids from vinyl or allyl ketones, and the corresponding alcohols, using olefin metathesis as a key reaction, was elaborated. The best yields and diastereoselectivities were obtained from allylic or homoallylic alcohols by employing the two‐step cross‐metathesis/oxidation procedure. The synthesized analogues were tested for their antiproliferative activity on human cancer cell lines of various origin (leukemia CEM, adenocarcinoma MCF7, cervical carcinoma HeLa) as well as for their antioxidant and anti‐inflammatory activity in vitro. All examined derivatives exhibited strong anti‐inflammatory activity in vitro without affecting cell viability. They also showed strong cytotoxicity against leukemia cell line CEM, except for 18 and 35. The antioxidant activity of the tested compounds was rather weak. PMID:27547644

  2. Organocatalytic Synthesis of Tetrahydroquinolines from α,β-Unsaturated Ketones via 1,5-Hydride Transfer/Cyclization

    Kim, Dae Young [Soonchunhyang Univ., Asan (Korea, Republic of)


    We have presented the example of a organo-catalytic enantioselective hydride transfer/cyclization reaction cascade from cyclic amines containing α,β-unsaturated ketones. The synthetically useful ring-fused tetrahydroquinoline derivatives were obtained in moderate to high yields with moderate to high diastereoselectivities. Further investigations for an asymmetric version of this organocatalytic intramolecular redox reaction of α,β-unsaturated ketones are currently underway in our laboratory. The development for direct functionalization of sp{sup 3} C-H bonds has become an area of intense interest in synthetic organic chemistry. Because such reactions offer practical methods for the construction of structurally complex and biologically active organic molecules with atom- and step economy. The 1,5-hydride transfer and subsequent cyclization process is a well-known sp{sup 3} C-H bond function-alization strategy and has attracted considerable interest for its application in the synthesis of heterocyclic compounds.

  3. Total synthesis of dihydrolysergic acid and dihydrolysergol: development of a divergent synthetic strategy applicable to rapid assembly of D-ring analogs

    Lee, Kiyoun; Poudel, Yam B.; Glinkerman, Christopher M.; Boger, Dale L.


    The total syntheses of dihydrolysergic acid and dihydrolysergol are detailed based on a Pd(0)-catalyzed intramolecular Larock indole cyclization for the preparation of the embedded tricyclic indole (ABC ring system) and a subsequent powerful inverse electron demand Diels–Alder reaction of 5-carbomethoxy-1,2,3-triazine with a ketone-derived enamine for the introduction of a functionalized pyridine, serving as the precursor for a remarkably diastereoselective reduction to the N-methylpiperidine D-ring. By design, the use of the same ketone-derived enamine and a set of related complementary heterocyclic azadiene [4 + 2] cycloaddition reactions permitted the late stage divergent preparation of a series of alternative heterocyclic derivatives not readily accessible by more conventional approaches. PMID:26273113

  4. Stereoselective synthesis of (2S,3R)-α-hydroxy-β-amino acids (AHBAs): valinoctin A, (2S,3R)-3-amino-2-hydroxydecanoic acid, and a fluorescent-labeled (2S,3R)-AHBA.

    Deshmukh, Sharad Chandrakant; Talukdar, Pinaki


    We report the stereoselective synthesis of an alkynyl side-chain containing (2S,3R)-α-hydroxy-β-amino acid ((2S,3R)-AHBA) analogues. The Cu(I)-catalyzed reactions of (R)-glyceraldehyde acetonide and dibenzylamine with terminal alkynes provided the corresponding (2S,3R)-α-amino alcohols with good-to-excellent diastereoselectivity. Subsequent chemical transformations provided easy access to the alkynyl side-chain containing (2S,3R)-AHBAs. The utility of the methodology was demonstrated by the stereoselective synthesis of valinoctin A and (2S,3R)-3-amino-2-hydroxydecanoic acid ((2S,3R)-AHDA). Photophysical properties and cell permeability of a pyrene-labeled (2S,3R)-AHBA were also determined.

  5. The remarkable Red Rectangle: A Stairway to Heaven?


    responsible for the striking red colour of the Rectangle is not yet clear, but it is likely that they are some kind of hydrocarbon formed in the cool outflows from the central star. Another remarkable feature of the Red Rectangle, visible only with the superb resolution of the Hubble telescope, is the dark band passing across the central star. This is the shadow of a dense disc of dust that surrounds the star and obscures it from direct view. The light we see streams out along the axis of the disc, and is scattered towards us by dust particles. Astronomers have found that the central star is actually a close pair of stars orbiting each other with a period of about 10.5 months. Interactions between these stars have probably caused the ejection of the thick dust disc that obscures our view of the binary. The disc then funnels subsequent dust and gas outflows out along its axis, forming the bizarre bi-conical structure we see as the rung of the Red Rectangle. The reasons for these fresh periodic ejections of more gas and dust remain unknown. The Red Rectangle was first discovered during a rocket flight in the early 1970s, in which astronomers were searching for strong sources of infrared radiation. This infrared source lies about 2300 light-years from Earth in the direction of the constellation Monoceros. Stars surrounded by clouds of dust are often strong infrared sources because the dust is heated by the starlight and then re-radiates long-wavelength red light. Studies of HD 44179 with ground-based telescopes revealed a rectangular shape in the dust surrounding the star at the centre, leading to the name 'Red Rectangle', coined in 1973 by astronomers Martin Cohen and Mike Merrill. This image was made from observations taken on 17-18 March 1999 with Hubble’s Wide Field Planetary Camera 2.

  6. Gamma-Ray Attenuation Measurements as a Laboratory Experiment: Some Remarks

    Adamides, E.; Koutroubas, S. K.; Moshonas, N.; Yiasemides, K.


    In this article we make some significant remarks on the experimental study of the absorption of gamma radiation passing through matter. These remarks have to do with the seemingly unexpected trend of the measured intensity of radiation versus the thickness of the absorber, which puzzles students and its explanation eludes many laboratory…

  7. Gold-Catalyzed Cyclization Processes: Pivotal Avenues for Organic Synthesis.

    Kumar, Amit; Singh, Sukhdev; Sharma, Sunil K; Parmar, Virinder S; Van der Eycken, Erik V


    Over the years, gold catalysis has materialized as an incredible synthetic approach among the scientific community. Due to the trivial reaction conditions and great functional compatibility, these progressions are synthetically expedient, because practitioners can implement them to build intricate architectures from readily amassed building blocks with high bond forming indices. The incendiary growth of gold catalysts in organic synthesis has been demonstrated as one of the most prevailing soft Lewis acids for electrophilic activation of carbon-carbon multiple bonds towards a great assortment of nucleophiles. Nowadays, organic chemists consistently employ gold catalysts to carry out a diverse array of organic transformations to build unprecedented molecular architectures. Despite all these achievements and a plethora of reports, many vital challenges remain. In this account, we describe the reactivity of various gold catalysts towards cyclization processes developed over the years. These protocols give access to a wide scope of polyheterocyclic structures, containing different medium-sized ring skeletons. This is interesting, as the quest for highly selective reactions to assemble diversely functionalized products has attracted much attention. We envisage that these newly developed chemo-, regio-, and diastereoselective protocols could provide an expedient route to architecturally cumbersome heterocycles of importance for the pharmaceutical industry.

  8. First report of charge-transfer induced heat-set hydrogel. Structural insights and remarkable properties

    Bhattacharjee, Subham; Maiti, Bappa; Bhattacharya, Santanu


    The remarkable ability of a charge-transfer (CT) complex prepared from a pyrene-based donor (Py-D) and a naphthalenediimide-based acceptor (NDI-A) led to the formation of a deep-violet in color, transparent hydrogel at room temperature (RT-gel). Simultaneously, the RT-gel was diluted beyond its critical gelator concentration (CGC) to obtain a transparent sol. Very interestingly, the resultant sol, on heating above 70 °C, transformed into a heat-set gel instantaneously with a hitherto unknown CGC value. Detailed studies revealed the smaller globular aggregates of the RT-gels fuse to form giant globules upon heating, which, in turn, resulted in heat-set gelation through further aggregation. The thermoresponsive property of Py-D alone and 1 : 1 Py-D : NDI-A CT complex was investigated in detail which revealed the hydrophobic collapse of the oxyethylene chains of the CT complex upon heating was mainly responsible for heat-set gelation. Thixotropy, injectability, as well as stimuli responsiveness of the RT-gels were also addressed. In contrast, heat-set gel did not show thixotropic behavior. The X-ray diffraction (XRD) patterns of the xerogel depicted lamellar packing of the CT stacks in the gel phase. Single crystal XRD studies further evidenced the 1 : 1 mixed CT stack formation in the lamellae and also ruled out orthogonal hydrogen bonding possibilities among the hydrazide unit in the CT gel although such interaction was observed in a single crystal of NDI-A alone. In addition, a Ag+-ion triggered metallogelation of NDI-A and nematic liquid-crystalline property of Py-D were also observed.The remarkable ability of a charge-transfer (CT) complex prepared from a pyrene-based donor (Py-D) and a naphthalenediimide-based acceptor (NDI-A) led to the formation of a deep-violet in color, transparent hydrogel at room temperature (RT-gel). Simultaneously, the RT-gel was diluted beyond its critical gelator concentration (CGC) to obtain a transparent sol. Very interestingly, the

  9. Development of a third-generation total synthesis of (+)-discodermolide: an expedient Still-Gennari-type fragment coupling utilizing an advanced beta-ketophosphonate.

    Paterson, Ian; Lyothier, Isabelle


    [structure: see text] A novel total synthesis of the complex polyketide discodermolide, a promising anticancer agent of marine sponge origin, has been completed in 11.1% overall yield over 21 linear steps. This third-generation approach features an unprecedented Still-Gennari-type HWE olefination reaction between advanced C1-C8 beta-ketophosphonate 61 and C9-C24 aldehyde 7, introducing the (8Z)-alkene with 10:1 selectivity. The stereotetrad found in the C1-C8 subunit 61 was established via a highly diastereoselective boron-mediated aldol reaction/in situ reduction between ketone (S)-8 and 3-benzyloxypropanal. The (7S)-configuration was installed by the reduction of enone 73 with K-Selectride.

  10. Using heteroaryl-lithium reagents as hydroxycarbonyl anion equivalents in conjugate addition reactions with (S,S)-(+)-pseudoephedrine as chiral auxiliary; enantioselective synthesis of 3-substituted pyrrolidines.

    Alonso, Beatriz; Ocejo, Marta; Carrillo, Luisa; Vicario, Jose L; Reyes, Efraim; Uria, Uxue


    We have developed an efficient protocol for carrying out the stereocontrolled formal conjugate addition of hydroxycarbonyl anion equivalents to α,β-unsaturated carboxylic acid derivatives using (S,S)-(+)-pseudoephedrine as chiral auxiliary, making use of the synthetic equivalence between the heteroaryl moieties and the carboxylate group. This protocol has been applied as key step in the enantioselective synthesis of 3-substituted pyrrolidines in which, after removing the chiral auxiliary, the heteroaryl moiety is converted into a carboxylate group followed by reduction and double nucleophilic displacement. Alternatively, the access to the same type of heterocyclic scaffold but with opposite absolute configuration has also been accomplished by making use of the regio- and diastereoselective conjugate addition of organolithium reagents to α,β,γ,δ-unsaturated amides derived from the same chiral auxiliary followed by chiral auxiliary removal, ozonolysis, and reductive amination/intramolecular nucleophilic displacement sequence.

  11. Direct bis-arylation of cyclobutanecarboxamide via double C-H activation: an auxiliary-aided diastereoselective Pd-catalyzed access to trisubstituted cyclobutane scaffolds having three contiguous stereocenters and an all-cis stereochemistry.

    Parella, Ramarao; Gopalakrishnan, Bojan; Babu, Srinivasarao Arulananda


    An auxiliary-aided Pd-catalyzed highly diastereoselective double C-H activation and direct bis-arylation of methylene C(sp(3))-H bonds of cyclobutanecarboxamides and the syntheses of several novel trisubstituted cyclobutanecarboxamide scaffolds having an all-cis stereochemistry are reported. Extensive screening of various auxiliaries and reaction conditions was performed to firmly establish the optimized reaction conditions required for effecting the mono- or double C-H arylation of cyclobutanecarboxamides. The auxiliary-attached cyclobutanecarboxamides 15a, 15g, and 15h, prepared from the auxiliaries such as, 8-aminoquinoline, 2-(methylthio)aniline, and N',N'-dimethylethane-1,2-diamine were found to undergo an efficient direct bis-arylation. The Pd-catalyzed arylation reaction of N-(quinolin-8-yl)cyclobutanecarboxamide 15a with one equivalent or more of aryl iodides, afforded the corresponding bis-arylated cyclobutanecarboxamides 16a-y. Nevertheless, the Pd-catalyzed arylation of 15a with just 0.5 equiv of the aryl iodides 13a, 13b, 13e, and 13m, selectively gave the corresponding monoarylated cyclobutanecarboxamides 17a-17d. The Pd-catalyzed arylation of 15g or 15h with one equivalent or more of aryl iodides afforded the bis-arylated cyclobutanecarboxamides 19a-19c and 21a-21m, respectively. However, the Pd-catalyzed arylations of compounds 15g or 15h with just 0.5 equiv of aryl iodides were ineffective. The stereochemistry of compounds obtained in this work was unambiguously assigned from the X-ray structures of representative products.


    Tatiana Goryacheva


    Full Text Available The paper deals with the etymological research of five East.-Slav. dialectal words: баланцы, воронéць, забуглáть, щáя и малофéйки, regarding all the scope of their phonetic and semantic variants. The word баланцы was analyzed in the meanings ‘chatter’ and ‘small icicles’. In the former meaning it is either onomatopoetic word, or it could be deduced from protoslav. *bal- ‘speak’; the latter one is, probably, derivative from the former, which could be confirmed with the typological data. Ukr. воронéць in the meaning ‘drink produced with vodka or horilka’ is motivated by the horse colour. Despite the drinks, the paper observes some features of herbs and plants, described by means of other horse-suit words. Rus. dial. забуглáть, meaning ‘cover with snow flakes’ is attributed to the root *bug- < i.-e. *bheug(h-/*bhoug(h ‘bend, bow’, ‘oppress, bring to ruin’, known with its semantic capacity. Ukr. слово щáя ‘time before dawn’ is connected with the verb щавити ‘press, oppress’. The meaning of Russ. dial. малофéйки ‘waves, ripple on a water surface’ is deduced from the Russ. slang малафья ‘cum, wet dreem’, descending from the Greek μαλακία. 

  13. Concluding Remarks

    in Kigali earlier this year, and the resulting journal issue dedicated to nursing and midwifery, are the first steps towards ... a leader in clinical care, research, and education. ... importance of measuring outcomes to improve future practice.

  14. Concluding remarks

    Kuiper, H.A.; König, A.; Kleter, G.A.; Hammes, W.P.; Knudsen, I.


    The most important results from the EU-sponsored ENTRANSFOOD Thematic Network project are reviewed, including the design of a detailed step-wise procedure for the risk assessment of foods derived from genetically modified crops based on the latest scientific developments, evaluation of topical risk

  15. Concluding remarks.

    Hafez, E S


    Focus in this discussion of IUDs is on types of IUD, fitting and insertion of IUDs, IUD management, physiology of IUDs, IUD pathology and management, and future development of IUDs. Several clinical trials are now underway in the effort to develop an IUD which will be able to lower the rate of pregnancies, expulsions, pain, bleeding, infections and other complications associated with IUD use. The use of proper techniques for insertion and placement of IUDs reduces the risk of uterine perforation, expulsion, pregnancy menstrual bleeding, pain and pelvic inflammatory disease. The device should be placed as high as possible in the endometrial cavity without perforating the uterine wall. In the absence of contraindications, IUDs can be used in adolescent females. The correct model should be selected and adapted individually to the sometimes underdeveloped uterine cavity. Side effects and complications of IUDs include uterine pain, dysfunctional uterine bleeding, expulsions, perforations, pelvic inflammatory disease, accidental intrauterine pregnancy and ectopic pregnancy. Novel approaches for future IUD improvement include medicated IUDs, medicated IUDs with compounds to reduce bleeding, IUDs designed to reduce expulsion after early postpartum and postabortion insertion, improved fit of IUD size and configuration to a given uterus, better insertion techniques and instrumentation, and application of biodegradables and polymeric delivery system.

  16. Opening Remarks


    @@To the respected Dr. Alex Malaspina, President of ILSI;Prof. Chen Chunming, principle organizer of the conference; distinguished guests and participants; ladies and gentlemen, welcome.   It is my great pleasure to address the Third Asian Conference on Food Safety and Nutrition on behalf of the Ministry of Health, the People's Republic of China. I would like to extend my sincere welcome to participants from Asia as well as participants from other continents.

  17. Concluding remarks

    Lerayer, Alda


    International audience; The focus of this Symposium was on bifidobacteria and propionibacteria for dairy and probiotic applications.Both genera have many similarities: being phylogenetically closely grouped within the Actinobacteria, they are high G+C branch Gram-positive bacteria, and share several physiological properties, despite having different industrial applications. It was highlighted in this Symposium that, from the point of view of consumers, consumer organizations, and government a...

  18. Introductory remarks

    Kiefer, Friedemann; Schulte-Merker, Stefan


    This introductory section briefly highlights the subsequent chapters in the context of recent findings and open questions in lymphatic vessel biology. It aims to provide a quick overview and orientation in the contents of this monograph collection.

  19. Zoogeographical remarks



    Much has been said of the geographical relations and the origin of the West Indian fauna, especially as to that of its vertebrates and mollusks. Mostly the islands off the Venezuelan coast, for the greater part within sight of the South American continent, remained out of question, although obvious

  20. Introductory Remarks

    T-D. Truong (Thanh-Dam); D.R. Gasper (Des)


    textabstractDriven by diverse forces – economic pressures and opportunities, climate change, war, conquest, and transformation of political regimes – human migration has been central to circulation of knowledge and values, goods and labour. Yet, it has been subject to mainly disciplinary inquiries a

  1. Concluding remarks

    Bjørnholm, S.


    Viewing cluster science as the embryology of the full-grown forms of matter we encounter in our surroundings, makes it appear to a relative newcomer as a highly dynamic discipline. Lines of attack showing marked progress or potential promise are briefly reviewed, and a sketch of the vast field of still-open problems is presented.

  2. Concluding remarks

    Bjoernholm, S. (Niels Bohr Inst., Copenhagen (Denmark))


    Viewing cluster science as the embryology of the full-grown forms of matter we encounter in our surroundings, makes it appear to a relative newcomer as a highly dynamic discipline. Lines of attack showing marked progress or potential promise are briefly reviewed, and a sketch of the vast field of still-open problems is presented. (orig.).

  3. Concluding Remarks

    Bonnet, Roger M.


    Let me first express my warmest acknowledgements to Cesare Barbieri for having taken the initiative of convening this symposium. These two days offered a unique opportunity to celebrate the scientific achievements and the legacy of Galileo Galilei. It allowed not only celebrating the scientist but also the philosopher and the human being. It was a fantastic journey in the past, present and future exploration of our universe and a fantastic retrospection into the Renaissance world which no better city than Padova would be able to offer. During these two days we could listen to a well balanced and well prepared set of excellent papers and presentations. All participants should be congratulated for their very active interactions during the discussions in the aula and also during coffee and lunch breaks.

  4. Introductory Remarks

    Killian, James


    Honored guest, ladies and gentlemen. We at M.I.T. rejoice that so many of you from near and far are with us these two days in honoring our cherished colleague, Victor Weisskopf. I say Victor but that does not carry the appropriate ring -- the appropriate ring of affection. I am reminded of a story about the late Charles Evans Hughes, once the Chief Justice of the U.S. Supreme Court and candidate for President, a man of formidable accomplishments in his profession and in public life. One day his young granddaughter boldly asked him what she should call him, and the Chief Justice replied: "Those who love me call me Charlie". And so, despite his formidable array of titles, responsibilities, accomplishments, honors, and accolades, we all feel more comfortable in addressing Victor as "Viki"...



    In this remark,we shall show some counter examples for the main results of the recent paper "Asymptotic Behavior of Delay 2-D Discrete Logistic Systems" (IEEE Trans.Circuits Systems,49(2002),1677-1682.)

  6. Some remarks on the genericity of unique range sets for meromorphic functions

    Ha Huy Khoai


    In this paper we relate the study of unique range sets for meromorphic functions (URSM) with the hyperbolic hypersurfaces and give some remarks on the genericity of unique range sets for meromorphic functions.

  7. Academy of Program/Project & Engineering Leadership: Shared Voyage: Learning and Unlearning from Remarkable Projects

    National Aeronautics and Space Administration — Shared Voyage is about four remarkable projects:the Advanced Composition Explorer (NASA), the Joint Air-to-Surface Standoff Missile (U.S. Air Force), the Pathfinder...

  8. A remark for "Linearization, stability, and oscillation of the discrete delayed logistic system"

    Zhang, Binggen


    In this remark, we shall show three counter examples for the main results to the paper [Guanrong Chen, Shu Tang Liu, Linearization, stability, and oscillation of the discrete delayed logistic system, IEEE Trans. Circuits Syst. 50 (2003) 822-826].

  9. A Study on the Pragmatic Strategies of Foreign Ministry Spokesperson’s Remarks



    As an important diplomacy activity, Foreign Ministry spokesperson’s remarks represent national image and foreign pol-icy of a country which is absolutely significant. This article would analyze the pragmatic strategies of Foreign Ministry spokesper-son’s remarks from the perspective of journalist’s questioning types and spokesperson’s answering types in order to get a clear idea about how spokesperson tactfully employing pragmatic strategies to handle tough questions and safeguard national interests.

  10. PREFACE: Introductory remarks Introductory remarks

    Bowler, D. R.; Alfe, D.


    This special issue contains papers related to the 2009 Thomas Young Centre Workshop at University College London 'Accessing large length and time scales with accurate quantum methods', in celebration of Professor Michael Gillan's 65th birthday. Mike Gillan won the 2006 Institute of Physics Dirac Medal and Prize, the citation reading: 'For his contributions to the development of atomic-scale computer simulations, which have greatly extended their power and effectiveness over an immense range of applications'. This rightly highlights Mike's seminal work on materials modelling, but misses out some of the many other areas he has enriched. After taking his PhD at the Department of Theoretical Physics, Oxford University, Mike went as a post-doc to Minneapolis. He then joined the Statistical Physics Group in the Theoretical Physics Division, Harwell, where he stayed for over 20 years, with a brief interlude in Saclay. In the late 1980s, Mike made a transition to become Professor of Physics at the University of Keele, where he stayed for a decade until University College London was fortunate in being able to tempt him to join the Condensed Matter and Material Physics Group, where there was already a significant materials modelling initiative. Over the years, Mike has made many important contributions, some with impact on other areas of science, others with significance in technology areas such as nuclear safety. Thus, he developed a form of quantum transition-state theory, generalizing Eyring's well-known classical transition-state theory to the case of quantum particles, such as hydrogen, diffusing in condensed matter. He pioneered quantum methods for calculating defect energetics in solids, and then molecular processes on surfaces. He synthesised these approaches into very general ways to calculate thermodynamic free energies of condensed matter from first principles, drawing on his early experience of statistical physics. These methods led to rapid advances in the study of matter under extreme conditions, as in the Earth's core. A further powerful development has been his input to linear-scaling quantum techniques for the properties of very large complex systems. In recent years, his attention has shifted towards increasing accuracy, touching areas such as quantum Monte Carlo and hierarchical quantum chemical techniques. In this journal issue, we have papers which both reflect topics from the workshop and address a number of areas which are directly in Mike's interests or which have been influenced by his work or assistance. There are papers addressing accuracy in quantum simulations [1-5], methods for applying quantum techniques to large systems [6, 7] and applications of quantum simulations to important problems [8-10]. We also have a viewpoint on magnetism in oxides and carbon [11], prompted by Mike's innovative work on oxides. References [1] Nolan S J, Bygrave P J, Allan N L and Manby F R 2010 J. Phys.: Condens. Matter 22 074201 [2] Badinski A, Haynes P D, Trail J R and Needs R J 2010 J. Phys.: Condens. Matter 22 074202 [3] Klimeš J, Bowler D R and Michaelides A 2010 J. Phys.: Condens. Matter 22 074203 [4] Baroni S, Gebauer R, Malcιoğlu O B, Saad Y, Umari P and Xian J 2010 J. Phys.: Condens. Matter 22 074204 [5] Toton D, Lorenz C D, Rompotis N, Martsinovich N and Kantorovich L 2010 J. Phys.: Condens. Matter 22 074205 [6] Fujiwara T, Hoshi T, Yamamoto S, Sogabe T and Zhang S-L 2010 J. Phys.: Condens. Matter 22 074206 [7] Bowler D R and Miyazari T 2010 J. Phys.: Condens. Matter 22 074207 [8] Er S, van Setten M J, de Wijs G A and Brocks G 2010 J. Phys.: Condens. Matter 22 074208 [9] Pan D, Liu L-M, Tribello G A, Slater B, Michaelides A and Wang E 2010 J. Phys.: Condens. Matter 22 074209 [10] Choudhury R, Gattinoni C, Makov G and De Vita A 2010 J. Phys.: Condens. Matter 22 074210 [11] Stoneham M 2010 J. Phys.: Condens. Matter 22 074211

  11. Solid-phase synthesis and structural characterization of highly substituted hydroxyproline-based 2,5-diketopiperazines

    Bianco; Sonksen; Roepstorff


    Two general solid-phase methods for the synthesis of a new class of 2,5-diketopiperazines (DKPs) containing the trans-4-hydroxy-L-proline amino acid residue (Hyp) have been developed. An N-protected hydroxyproline methyl ester was linked through the hydroxyl function to the Ellman resin. The synt......Two general solid-phase methods for the synthesis of a new class of 2,5-diketopiperazines (DKPs) containing the trans-4-hydroxy-L-proline amino acid residue (Hyp) have been developed. An N-protected hydroxyproline methyl ester was linked through the hydroxyl function to the Ellman resin....... The synthesis procedures were conceived to enable a sequence of Hyp alkylation, Hyp N-acylation, cyclization, and amide bond alkylation. Up to three different centers of molecular diversity were introduced around the DKP scaffold. Highly functionalized bicyclic compounds were obtained in good yield and purity....... The alkylation of hydroxyproline alpha CH was performed without control of the diastereoselectivity. During the final alkylation of the backbone, amide bond epimerization at the alpha-carbon atoms of the two amino acid residues was observed. The structures of representative DKPs were elucidated...

  12. Graphite oxide/metal-organic framework (MIL-101): remarkable performance in the adsorptive denitrogenation of model fuels.

    Ahmed, Imteaz; Khan, Nazmul Abedin; Jhung, Sung Hwa


    A highly porous metal-organic framework (MOF), MIL-101 (Cr-benzenedicarboxylate), was synthesized in the presence of graphite oxide (GO) to produce GO/MIL-101 composites. The porosity of the composites increased remarkably in the presence of a small amount of GO (adsorptions. The adsorptive removal of nitrogen-containing compounds (NCCs) and sulfur-containing compounds (SCCs) from model fuels demonstrated the potential applications of the composites in adsorptions, and the adsorption capacity was dependent on the surface area and pore volume of the composites. Most importantly, the GO/MIL-101 composite has the highest adsorption capacity for NCCs among reported adsorbents so far, partly because of the increased porosity of the composite. Finally, the results suggest that GO could be used in the synthesis of highly porous MOF composites, and the obtained materials could be used in various adsorptions in both liquid and gas/vapor phase (such as H2, CH4, and CO2 storage) adsorptions, because of the high porosity and functional GO.

  13. Towards the total synthesis of keramaphidin B

    Jakubec, Pavol; Farley, Alistair J M


    Summary The enantio- and diastereoselective Michael addition of a δ-valerolactone-derived pronucleophile to a substituted furanyl nitroolefin catalysed by a bifunctional cinchonine-derived thiourea has been used as the key stereocontrolling step in a new synthetic strategy to the heavily functionalised piperidine core of keramaphidin B. PMID:27340496

  14. A stereodivergent strategy for the preparation of corynantheine and ipecac alkaloids, their epimers, and analogues: efficient total synthesis of (-)-dihydrocorynantheol, (-)-corynantheol, (-)-protoemetinol, (-)-corynantheal, (-)-protoemetine, and related natural and nonnatural compounds.

    Zhang, Wei; Bah, Juho; Wohlfarth, Andreas; Franzén, Johan


    Here we present a general and common catalytic asymmetric strategy for the total and formal synthesis of a broad number of optically active natural products from the corynantheine and ipecac alkaloid families, for example, indolo[2,3-a]- and benzo[a]quinolizidines. Construction of the core alkaloid skeletons with the correct absolute and relative stereochemistry relies on an enantioselective and diastereodivergent one-pot cascade sequence followed by an additional diastereodivergent reaction step. This allows for enantio- and diastereoselective synthesis of three out of four possible epimers of the quinolizidine alkaloids that begin from common and easily accessible starting materials by using a common synthetic route. Focus has been made on excluding protecting groups and limiting isolation and purification of synthetic intermediates. This methodology is applied in the total synthesis of the natural products (-)-dihydrocorynantheol, (-)-hirsutinol, (-)-corynantheol, (-)-protometinol, (-)-dihydrocorynantheal, (-)-corynantheal, (-)-protoemetine, (-)-(15S)-hydroxydihydrocorynantheol, and an array of their nonnatural epimers. The potential of this strategy is also demonstrated in the synthesis of biologically interesting natural product analogues not accessible through synthetic elaboration of alkaloid precursors available from nature, for example, thieno[3,2-a]quinolizidine derivatives. We also report the formal synthesis of (+)-dihydrocorynantheine, (-)-emetine, (-)-cephaeline, (-)-tubulosine, and (-)-deoxytubulosine.

  15. (NII) Novel Catalytic, Synthesis Methods for Main Group


    Application of Fundamental Organometallic Chemistry to the Development of a Gold- Catalyzed Synthesis of Sulfinate Derivatives.” Angew. Chem. Int. Ed. Engl...applied in selective functionalization of organic molecules. In recent chemistry relevant to this problem, we reported remarkable reactivity leading to

  16. Monolayer transition metal disulfide:Synthesis, characterization and applications

    Qi Fu; Bin Xiang


    Two-dimensional transition metal dichalcogenides (2D TMDCs) has aroused tremendous attention in recent years, because of their remarkable properties originated from their unique structure. In this re-view we report the synthesis, characterization and applications of monolayer MoS2 and WS2.

  17. Planar chiral (η6-arene)Cr(CO)3 containing carboxylic acid derivatives: synthesis and use in the preparation of organometallic analogues of the antibiotic platensimycin.

    Patra, Malay; Merz, Klaus; Metzler-Nolte, Nils


    With more and more organometallic compounds receiving attention for applications in medicinal organometallic chemistry, the need arises for stereoselective syntheses of more complicated structures containing organometallic moieties, for example as isosteric substitutes for organic drug candidates. Herein, the synthesis and characterization of both diastereomers of a planar chiral (η(6)-arene)Cr(CO)(3) containing carboxylic acid derivative, namely, 3-{η(6)-(1, 2, 3, 4-tetrahydro-1-endo/exo-methyl-2-oxonaphthalen-1-yl)-tricarbonylchromium(0)}propanoic acid (7 and 8) is reported. The molecular structures of both were confirmed by single crystal X-ray diffraction. The degree of diastereoselectivity in Cr(CO)(3) complexation with methyl/tert-butyl-3-(1,2,3,4-tetrahydro-1-methyl-2-oxonaphthalen-1-yl)propanoate (4a/4b) vs. the Michael addition of methyl/tert-butyl acrylate to (η(6)-1-methyl-2-tetralone)Cr(CO)(3) (9) was also examined. In the latter case the alkylation was found to be completely diastereoselective and gave methyl/tert-butyl-3-{η(6)-(1, 2, 3, 4-tetrahydro-1-endo-methyl-2-oxonaphthalen-1-yl)-tricarbonylchromium (0)}propanoate (5a and 5b) in excellent yield. Both the carboxylic acids 7 and 8 were coupled with the aminoresorcyclic acid core to achieve diastereomeric bioorganometallics 15a and 15b based on the naturally occurring antibiotic platensimycin lead structure (1a, see Fig. 1). The newly synthesized bioorganometallics were tested against various Gram-positive and Gram-negative bacterial strains but show no promising antibacterial activity.

  18. Some Remarks on the Restriction Theorems for the Maximal Operators on Rd

    Enji Sato∗


    The aim of this paper is to give a simple proof of the restriction theorem for the maximal operators on the d-dimensional Euclidean space Rd, whose theorem was proved by Carro-Rodriguez in 2012.Moreover, we shall give some remarks of the restriction theorem for the linear and the multilinear operators by Carro-Rodriguez and Rodriguez, too.

  19. Non-recursive expressions for even-index Bernoulli numbers: A remarkable sequence of determinants

    Van Malderen, Renaat


    Bernoulli numbers are usually expressed in terms of their lower index numbers (recursive). This paper gives explicit formulas for Bernoulli numbers of even index. The formulas contain a remarkable sequence of determinants. The value of these determinants for variable dimension is investigated.

  20. Padé approximant related to remarkable inequalities involving trigonometric functions

    Gabriel Bercu


    Full Text Available Abstract In this paper we, respectively, give simple proofs of some remarkable trigonometric inequalities, based on the Padé approximation method. We also obtain rational refinements of these inequalities. We are convinced that the Padé approximation method offers a general framework for solving many other similar inequalities.

  1. A remarkable new species of Eutrichopoda Townsend, 1908 (Diptera: Tachinidae: Phasiinae).

    Dios, Rodrigo De Vilhena Perez; Nihei, Silvio Shigueo


    A new Tachinidae species, Eutrichopoda flavipenna sp. nov. (Diptera: Tachinidae: Phasiinae), from Brazil and Paraguay is described and illustrated by photographs and line drawings. The remarkable yellow, feather-like setae on the hind tibia distinguishes the new species from all other species in the tribe Trichopodini.

  2. Remarks on the thermopreferendum of palearctic bats in their natural habitats

    Gaisler, Jiří


    This contribution comprises two remarks of ecological rather than physiological character. Contrary to Herter (1952), Herreid (1967), and Harmata (1969), I did not examine the temperature preference, or thermopreferendum, of bats under experimental conditions but concluded on it only on grounds of

  3. The Public University in South Africa: Philosophical Remarks on the Notion of "Elitist Knowledge" Production

    Waghid, Yusef


    In my remarks about elitist knowledge production, I firstly try to adjust the perspective from which the university could be analysed; I specifically explore the functions of the university in relation to Habermas's categorisation of knowledge. Secondly, with reference to Derrida's reflections on the university, I reformulate a conception of the…

  4. Remarks on the Distribution and Migration of Whales, based on Observations from Netherlands Ships

    Slijper, E.J.; Utrecht, van W.L.; Naaktgeboren, C.


    A. GENERAL REMARKS During three years 4500 reports of whales sighted from Netherlands ships were collected, bearing on approximately 11.000 individual animals. Most of the observations were made in the Atlantic and Indian Ocean. It was supposed that the species could be determined with a fairly high

  5. Comparative hazard analysis of processes leading to remarkable flash floods (France, 1930-1999)

    Boudou, M.; Lang, M.; Vinet, F.; Cœur, D.


    Flash flood events are responsible for large economic losses and lead to fatalities every year in France. This is especially the case in the Mediterranean and oversea territories/departments of France, characterized by extreme hydro-climatological features and with a large part of the population exposed to flood risks. The recurrence of remarkable flash flood events, associated with high hazard intensity, significant damage and socio-political consequences, therefore raises several issues for authorities and risk management policies. This study aims to improve our understanding of the hazard analysis process in the case of four remarkable flood events: March 1930, October 1940, January 1980 and November 1999. Firstly, we present the methodology used to define the remarkability score of a flood event. Then, to identify the factors leading to a remarkable flood event, we explore the main parameters of the hazard analysis process, such as the meteorological triggering conditions, the return period of the rainfall and peak discharge, as well as some additional factors (initial catchment state, flood chronology, cascade effects, etc.). The results contribute to understanding the complexity of the processes leading to flood hazard and highlight the importance for risk managers of taking additional factors into account.

  6. Remarks on the thermopreferendum of palearctic bats in their natural habitats

    Gaisler, Jiří


    This contribution comprises two remarks of ecological rather than physiological character. Contrary to Herter (1952), Herreid (1967), and Harmata (1969), I did not examine the temperature preference, or thermopreferendum, of bats under experimental conditions but concluded on it only on grounds of t

  7. Remarks on the Distribution and Migration of Whales, based on Observations from Netherlands Ships

    Slijper, E.J.; Utrecht, van W.L.; Naaktgeboren, C.


    A. GENERAL REMARKS During three years 4500 reports of whales sighted from Netherlands ships were collected, bearing on approximately 11.000 individual animals. Most of the observations were made in the Atlantic and Indian Ocean. It was supposed that the species could be determined with a fairly high

  8. The Public University in South Africa: Philosophical Remarks on the Notion of "Elitist Knowledge" Production

    Waghid, Yusef


    In my remarks about elitist knowledge production, I firstly try to adjust the perspective from which the university could be analysed; I specifically explore the functions of the university in relation to Habermas's categorisation of knowledge. Secondly, with reference to Derrida's reflections on the university, I reformulate a conception of the…

  9. An efficient synthesis of loline alkaloids

    Cakmak, Mesut; Mayer, Peter; Trauner, Dirk


    Loline (1) is a small alkaloid that, in spite of its simple-looking structure, has posed surprising challenges to synthetic chemists. It has been known for more than a century and has been the subject of extensive biological investigations, but only two total syntheses have been achieved to date. Here, we report an asymmetric total synthesis of loline that, with less then ten steps, is remarkably short. Our synthesis incorporates a Sharpless epoxidation, a Grubbs olefin metathesis and an unprecedented transannular aminobromination, which converts an eight-membered cyclic carbamate into a bromopyrrolizidine. The synthesis is marked by a high degree of chemo- and stereoselectivity and gives access to several members of the loline alkaloid family. It delivers sufficient material to support a programme aimed at studying the complex interactions between plants, fungi, insects and bacteria brokered by loline alkaloids.

  10. One-Pot Synthesis of 2-Acylindole-3-acetylketones via Domino Aza-alkylation/Michael Reaction Using o-Aminophenyl α,β-Unsaturated Ketones Followed by Desulfonative Dehydrogenation

    Kim, A Reum; Yu, Mi Rim; Sim, Jong Tack; Kim, Sung Gon [Kyonggi Univ., Suwon (Korea, Republic of)


    The development of novel and practical synthetic methods with a minimum number of operations for the construction of bioactive structurally complex compounds is a major challenge in synthetic organic chemistry. Recently, we reported an efficient method for the stereoselective synthesis of 2,3-disubstituted indoline derivatives; cis-2,3-disubstituted indolines were obtained by the aza-alkylation/Michael cascade reaction of 2-(tosylamino)phenyl α,β-unsaturated ketones with α-bromoacetophenones in good yields and with excellent diastereoselectivities (Scheme 2, Eq. (1)). Among the available synthetic strategies, domino or cascade reactions have received wide acceptance as highly efficient and powerful methods for the synthesis of molecules with a high structural complexity. An efficient synthesis of 2,3-disubstituted indoles was developed by the domino aza-alkylation/intramolecular Michael reaction of 2-(tosylamino)phenyl α,β-unsaturated ketones with α-bromoacetophenones, followed by desulfonative dehydrogenation with DBU. The reaction afforded structurally diverse and highly functionalized 2,3-disubstituted indoles in moderate to excellent yields (up to 99%). The synthesis of 2,3-disubstituted indoles without desulfonation through DDQ-induced oxidative dehydrogenation was also achieved.

  11. Four recent books on spirituality and the Psalms: some contextualising, analytical and evaluative remarks

    CJS Lombaard


    Full Text Available In the four years from 2002 to 2005, four new books on the Psalms and spirituality have been published. These are:� �� Stuhlmueller, C 2002.� The spirituality of the Psalms. Collegeville, Minnesota: Liturgical Press. �� Brueggemann,� W 2002. Spirituality of the Psalms. Minneapolis: Fortress Press. �� Waaijman, K 2004. Mystiek in de psalmen. Baarn: Uitgeverij Ten Have. �� Firth, D G� 2005. Hear , o Lord. A spirituality of the Psalms. Calver: Cliff College Publishing. In this paper, brief remarks on the context within which this publication trend takes place, are made. Each of the works is then briefly described, and general evaluative remarks are concluded with.

  12. Stereoselective synthesis and structure-affinity relationships of bicyclic kappa receptor agonists.

    Kracht, Daniel; Rack, Elisabeth; Schepmann, Dirk; Fröhlich, Roland; Wünsch, Bernhard


    Reductive amination of the bicyclic ketone 4 led diastereoselectively to endo-configured amines, which were transformed into the amides 7-10. The synthesis of the diastereomers 25 with an exo-configured amino moiety at position 6 was only successful after deactivation of both N-atoms of the 1,4-diazabicyclo[3.3.1]nonane system. The N-1-oxide 19 with an N-4-tosyl moiety was the crucial intermediate, which allows SN2 substitution with NaN3 under inversion of the configuration at position 6. Whereas the endo-configured pyrrolidine 7a (WMS-1302) revealed a kappa receptor affinity of 73 nM, the exo-configured diastereomer 25a was almost inactive at the kappa receptor (Ki > 1 microM). Replacement of the 3,4-dichlorophenylacetyl residue by other acyl and sulfonyl residues showed that it is essential for high kappa affinity. The kappa receptor affinities of the conformationally constrained pyrrolidines 7a and 25a were correlated with the dihedral angle N(pyrrolidine)-C-C-N(acetamide). A systematic conformational analysis of the potent but flexible kappa agonist 2 showed that a dihedral angle of 168 degrees (as in 25a) is energetically more disfavored than a dihedral angle of 58 degrees (7a). However, even the conformation with a dihedral angle of 58 degrees does not represent an energy minimum, which might explain the reduced kappa affinity of 7a.

  13. Remarkable discovery in a cave of south west Morocco: Siagona taggadertensis n.sp. (Carabidae: Siagoninae)

    Junger, Bernard; Faille, Arnaud


    [EN] Five species of the genus Siagona Latreille 1804 (Carabidae: Siagoninae) are known from Morocco. Siagona taggadertensis n. sp., a remarkable species of Carabidae from a Moroccan cave is described. This insect is spectacular by its large size (one of the largest species of the genus), its external morphology, which isolates it from all the north african representant of the genus, and for the conditions of its discovery: its only known from the remains of six specimens, all of them foun...

  14. The Diamond Light Source and the challenges ahead for structural biology: some informal remarks.

    Ramakrishnan, V


    The remarkable advances in structural biology in the past three decades have led to the determination of increasingly complex structures that lie at the heart of many important biological processes. Many of these advances have been made possible by the use of X-ray crystallography using synchrotron radiation. In this short article, some of the challenges and prospects that lie ahead will be summarized.

  15. Remarks on the Existence and Uniqueness of Unbounded Viscosity Solutions of Hamilton-Jacobi Equations.


    many more resu -s of this kind, including existence results in cases where nonuniqueness is possible and the existence of minimal solutions. We these works. -4- . .. . . . . . . . . * .. ..-.. .. ... . .. . .. . .. . .. . .. . .. . . H CONTENTS I. Lipschitz Hamiltonians and the stationary...condition~s at infinity VII. Further remarks on the Cauchy problem V -5-r 1. LIPSCHITZ HAMILTONIANS AN-D THE STATIONARY PROBLEM. wilIn this section we

  16. Remarks on certain new methods for blind identification of FIR channels

    P. P. Vaidyanathan; Su, Borching


    This paper discusses a number of issues pertaining to blind identification of channels. The basics of blind identification are first discussed and a method called Vandermonde method is presented which is based on elementary linear system principles. Then some remarks are made about precoders with paraunitary antipodal preprocessors. It is argued that such preprocessors usually destroy signal richness which is a necessary feature in blind identification systems.

  17. The Remarkable Frequency of Human Immunodeficiency Virus Type 1 Genetic Recombination


    Summary: The genetic diversity of human immunodeficiency virus type 1 (HIV-1) results from a combination of point mutations and genetic recombination, and rates of both processes are unusually high. This review focuses on the mechanisms and outcomes of HIV-1 genetic recombination and on the parameters that make recombination so remarkably frequent. Experimental work has demonstrated that the process that leads to recombination—a copy choice mechanism involving the migration of reverse transcr...

  18. Total Synthesis of Vinblastine, Vincristine, Related Natural Products, and Key Structural Analogues

    Ishikawa, Hayato; Colby, David A.; Seto, Shigeki; Va, Porino; Tam, Annie; Kakei, Hiroyuki; Rayl, Thomas J.; Hwang, Inkyu; Boger, Dale L.


    Full details of the development of a direct coupling of catharanthine with vindoline to provide vinblastine are described along with key mechanistic and labeling studies. Following an Fe(III)-promoted coupling reaction initiated by generation of a presumed catharanthine radical cation that undergoes a subsequent oxidative fragmentation and diastereoselective coupling with vindoline, addition of the resulting reaction mixture to an Fe(III)–NaBH4/air solution leads to oxidation of the C15′–C20′ double bond and reduction of the intermediate iminium ion directly providing vinblastine (40–43%) and leurosidine (20–23%), its naturally occurring C20′ alcohol isomer. The yield of coupled products, which exclusively possess the natural C16′ stereochemistry, approaches or exceeds 80% and the combined yield of the isomeric C20′ alcohols is >60%. Preliminary studies of Fe(III)–NaBH4/air oxidation reaction illustrate a generalizable trisubstituted olefin scope, identified alternatives to O2 trap at the oxidized carbon, provides a unique entry into C20′ functionalized vinblastines, and affords initial insights into the observed C20′ diastereoselectivity. The first disclosure of the use of exo-catharanthine proceeding through Δ19′,20′-anhydrovinblastine in such coupling reactions is also detailed with identical stereochemical consequences. Incorporating either a catharanthine N-methyl group or a vindoline N-formyl group precludes Fe(III)-promoted coupling, whereas the removal of the potentially key C16 methoxy group of vindoline does not adversely impact the coupling efficiency. Extension of these studies provided a total synthesis of vincristine (2) via N-desmethylvinblastine (36, also a natural product), 16-desmethoxyvinblastine (44) and 4-desacetoxy-16-desmethoxyvinblastine (47) both of which we can now suggest are likely natural products produced by C. roseus, desacetylvinblastine (62) and 4-desacetoxyvinblastine (59), as well as a series of key

  19. Stereoselective cathodic synthesis of 8-substituted (1R,3R,4S)-menthylamines.

    Edinger, Carolin; Kulisch, Jörn; Waldvogel, Siegfried R


    The electrochemical generation of menthylamines from the corresponding menthone oximes equipped with an additional substituent in position 8 is described. Due to 1,3-diaxial interactions a pronounced diastereoselectivity for the menthylamines is found.

  20. Stereoselective cathodic synthesis of 8-substituted (1R,3R,4S-menthylamines

    Carolin Edinger


    Full Text Available The electrochemical generation of menthylamines from the corresponding menthone oximes equipped with an additional substituent in position 8 is described. Due to 1,3-diaxial interactions a pronounced diastereoselectivity for the menthylamines is found.

  1. Some Remarks on the Riccati Equation Expansion Method for Variable Separation of Nonlinear Models

    Zhang, Yu-Peng; Dai, Chao-Qing


    Based on the Riccati equation expansion method, 11 kinds of variable separation solutions with different forms of (2+1)-dimensional modified Korteweg-de Vries equation are obtained. The following two remarks on the Riccati equation expansion method for variable separation are made: (i) a remark on the equivalence of different solutions constructed by the Riccati equation expansion method. From analysis, we find that these seemly independent solutions with different forms actually depend on each other, and they can transform from one to another via some relations. We should avoid arbitrarily asserting so-called "new" solutions; (ii) a remark on the construction of localised excitation based on variable separation solutions. For two or multi-component systems, we must be careful with excitation structures constructed by all components for the same model lest the appearance of some un-physical structures. We hope that these results are helpful to deeply study exact solutions of nonlinear models in physical, engineering and biophysical contexts.

  2. Microwave Synthesis of Cathode Material LixMn2O4 for Lithium-ion Battery

    HAO Hua; LIU Han-xing; OUYANG Shi-xi


    LiMn2O4 was synthesized rapidly by microwa e heating. The product phases of the microwave synthesis and conventional solid-state synthesis were comparatively invesitigated. The capacity of microwave synthesis product decreases relatively slow. The lithium ion can be inserted into and extracted from the spinel framework structure fluently after cycling. But the capacity of the conventional solid-state synthesis product is more remarkably lowered. The spinel framework structure was destroyed which hindered the lithium ion from inserting and extracting. The influential factors of the process parameters are discussed such as heat preservation time, pre-heating at 400℃ for 24h and coupled agent.

  3. Organic Synthesis

    Romea, Pedro


    Organic Synthesis is a one-semester course of the fourth year of the Chemistry Degree at the Universitat de Barcelona. This course covers the most important transformations in Organic Chemistry, including a short introduction to the Retrosynthetic Analysis. The aim is to provide a solid knowledge of the main reactions and their mechanism, which could later be improved during Master studies.

  4. Cyclodextrin-Scaffolded Alamethicin with Remarkably Efficient Membrane Permeabilizing Properties and Membrane Current Conductance

    Hjørringgaard, Claudia Ulrich; Vad, Brian Stougaard; Matchkov, Vladimir


    the dynamics of assembly and to facilitate a thorough structural evaluation of the alamethicin ion-channels, we have applied click chemistry for the synthesis of templated alamethicin multimers covalently attached to cyclodextrin-scaffolds. Using oriented circular dichroism, calcein release assays, and single...

  5. Characterization of remarkable floods in France, a transdisciplinary approach applied on generalized floods of January 1910

    Boudou, Martin; Lang, Michel; Vinet, Freddy; Coeur, Denis


    The 2007 Flood Directive promotes the integration and valorization of historical and significant floods in flood risk management (Flood Directive Text, chapter II, and article 4). Taking into account extreme past floods analysis seems necessary in the mitigation process of vulnerability face to flooding risk. In France, this aspect of the Directive was carried out through the elaboration of Preliminary Flood Risk Assessment (PFRA) and the establishment of a 2000 floods list. From this first list, a sample of 176 floods, considered as remarkable has been selected. These floods were compiled in discussion with local authorities in charge of flood management (Lang et al., 2012) and have to be integrated in priority in local risk management policies. However, a consideration emerges about this classification: how a remarkable flood can be defined? According which criteria can it be considered as remarkable? To answer these questions, a methodology has been established by building an evaluation grid of remarkable floods in France. The primary objective of this grid is to analyze the remarkable flood's characteristics (hydrological and meteorological characteristics, sociological- political and economic impacts), and secondly to propose a classification of significant floods selected in the 2011 PFRA. To elaborate this evaluation grid, several issues had to be taken into account. First, the objective is to allow the comparison of events from various periods. These temporal disparities include the integration of various kinds of data and point out the importance of historical hydrology. It is possible to evaluate accurately the characteristics of recent floods by interpreting quantitative data (for example hydrological records. However, for floods that occurred before the 1960's it is necessary resorting to qualitative information such as written sources is necessary (Coeur, Lang, 2008). In a second part the evaluation grid requires equitable criteria in order not to

  6. Synthesis of fluorinated β-aminophosphonates and γ-lactams.

    Alonso, Concepción; González, María; Fuertes, María; Rubiales, Gloria; Ezpeleta, Jose María; Palacios, Francisco


    The functionalized polyfluorophosphorylated 1-azadienes I have been prepared by a Wittig reaction of ethyl glyoxalate and perfluorophosphorylated conjugated phosphoranes, obtained by reaction of phosphazenes and fluorinated acetylenic phosphonates. Subsequent reduction of both carbon-carbon and carbon-nitrogen double bonds of these 1-azadienes I affords the fluorine-containing β-aminophosphonates II, with the syn β-aminophosphonate being obtained as the major diastereoisomer. Base-mediated cyclocondensation of a diastereomeric mixture of aminophosphonates II leads exclusively to a new type of functionalized trans-γ-lactams III in a diastereoselective way. A computational study has also been used to explain the observed diastereoselectivity of these reactions.

  7. Remarkable anatomic variations in paranasal sinus region and their clinical importance

    Kantarci, Mecit E-mail:; Karasen, R. Murat; Alper, Fatih; Onbas, Omer; Okur, Adnan; Karaman, Adem


    With the advent of functional endoscopic sinus surgery (FESS) and coronal computed tomography (CT) imaging, considerable attention has been directed toward paranasal region anatomy. Detailed knowledge of anatomic variations in paranasal sinus region is critical for surgeons performing endoscopic sinus surgery as well as for the radiologist involved in the preoperative work-up. To be in the known anatomical variants with some accompanying pathologies, directly influence the success of diagnostic and therapeutic management of paranasal sinus diseases. A review of 512 (1024 sides) paranasal sinus tomographic scans was carried out to expose remarkable anatomic variations of this region. We used only coronal sections, but for some cases to clear exact diagnosis, additional axial CT scan, magnetic resonance imaging (MRI) and nasal endoscopy were also performed. In this pictorial essay, rates of remarkable anatomic variations in paranasal region were displayed. The images of some interesting cases were illustrated, such as the Onodi cell in which isolated mucocele caused loss of visual acuity, agger nasi cell, Haller's cell, uncinate bulla, giant superior concha bullosa, inferior concha bullosa, bilateral carotid artery protrusion into sphenoid sinus, maxillary sinus agenesis, bilateral secondary middle turbinate (SMT) and sphenomaxillary plate. The clinical importance of all these variations were discussed under the light of the literature. It was suggested that remarkable anatomic variations of paranasal region and their possible pathologic consequences should be well defined in order to improve success of management strategies, and to avoid potential complications of endoscopic sinus surgery. The radiologist must pay close attention to anatomical variations in the preoperative evaluation.

  8. A Remarkable Collection of Rare Scriptures in a Small University Library Setting

    Teresa Cardin Ellis


    Full Text Available Hardin-Simmons University was given two remarkable collections of rare Bibles and a Sefer Torah with the expressed desire of the donors for the collections to be shared with students, faculty and other constituencies of the university's Richardson Library. The library has tried to fulfill this request while attempting to preserve these treasures for future generations. As small university, without a trained archivist or preservationist, we have utilized resources outside our library and contiue to pursue sources to assist us in the maintenance of these special collections while still engaging them in the educational process.

  9. Concluding remarks and outlook: Europhysics conference on flavor-mixing in weak interactions

    Chau, L.L.


    Some comments are offered on the present knowledge of the mixing matrix of Kobayashi and Maskawa and of the dynamics of nonleptonic decay. Also, remarks are made concerning CP violation. Plans for research from 1984 to 1989 are listed briefly. The history of studies on weak interactions is briefly reviewed, and several unanswered questions are stated, such as where are the truth particles, how may they be discovered, what is the mass-generating mechanism for the gauge bosons, how many Z/sup 0/'s and W's are there, do neutrinos have mass, and how long do protons live. (LEW)

  10. Bildung In A New Context In Danish University Teaching With Some Remarkable Results

    Olesen, Mogens Nørgaard


    In this paper we will look at the pedagogical concept of Bildung and how Bildung has been used as an important ingredient of European university teaching during the last 200 years. We will also shortly look at the modern university teaching where Bildung in some important respects has been...... of Bildung in an new modern context were included in the lectures. This had a remarkable impact. The students became more interested and more studious. How this was practically done will be the main item of this paper and it will be shown thar Bildung is very central if we want to develop university teaching...

  11. Remarkable enhancement of the electrical conductivity of carbon nanostructured thin films after compression.

    Georgakilas, Vasilios; Koutsioukis, Apostolos; Petr, Martin; Tucek, Jiri; Zboril, Radek


    In this work, we demonstrate a significant improvement in the electrical conductivity of carbon nanostructured thin films, composed of graphene nanosheets and multiwalled carbon nanotubes, by compression/polishing. It is shown that the sheet resistance of compressed thin films of carbon nanostructures and hybrids is remarkably decreased in comparison with that of as-deposited films. The number of the interconnections, the distance between the nanostructures as well as their orientation are highly altered by the compression favoring the electrical conductivity of the compressed samples.

  12. Synthesis of constrained analogues of tryptophan

    Elisabetta Rossi


    Full Text Available A Lewis acid-catalysed diastereoselective [4 + 2] cycloaddition of vinylindoles and methyl 2-acetamidoacrylate, leading to methyl 3-acetamido-1,2,3,4-tetrahydrocarbazole-3-carboxylate derivatives, is described. Treatment of the obtained cycloadducts under hydrolytic conditions results in the preparation of a small library of compounds bearing the free amino acid function at C-3 and pertaining to the class of constrained tryptophan analogues.

  13. Search for genes responsible for the remarkably high acetic acid tolerance of a Zygosaccharomyces bailii-derived interspecies hybrid strain.

    Palma, Margarida; Roque, Filipa de Canaveira; Guerreiro, Joana Fernandes; Mira, Nuno Pereira; Queiroz, Lise; Sá-Correia, Isabel


    Zygosaccharomyces bailii is considered the most problematic acidic food spoilage yeast species due to its exceptional capacity to tolerate high concentrations of weak acids used as fungistatic preservatives at low pH. However, the mechanisms underlying its intrinsic remarkable tolerance to weak acids remain poorly understood. The identification of genes and mechanisms involved in Z. bailii acetic acid tolerance was on the focus of this study. For this, a genomic library from the highly acetic acid tolerant hybrid strain ISA1307, derived from Z. bailii and a closely related species and isolated from a sparkling wine production plant, was screened for acetic acid tolerance genes. This screen was based on the transformation of an acetic acid susceptible Saccharomyces cerevisiae mutant deleted for the gene encoding the acetic acid resistance determinant transcription factor Haa1. The expression of 31 different DNA inserts from ISA1307 strain genome was found to significantly increase the host cell tolerance to acetic acid. The in silico analysis of these inserts was facilitated by the recently available genome sequence of this strain. In total, 65 complete or truncated ORFs were identified as putative determinants of acetic acid tolerance and an S. cerevisiae gene homologous to most of them was found. These include genes involved in cellular transport and transport routes, protein fate, protein synthesis, amino acid metabolism and transcription. The role of strong candidates in Z. bailii and S. cerevisiae acetic acid tolerance was confirmed based on homologous and heterologous expression analyses. ISA1307 genes homologous to S. cerevisiae genes GYP8, WSC4, PMT1, KTR7, RKR1, TIF3, ILV3 and MSN4 are proposed as strong candidate determinants of acetic acid tolerance. The ORF ZBAI_02295 that contains a functional domain associated to the uncharacterised integral membrane proteins of unknown function of the DUP family is also suggested as a relevant tolerance determinant

  14. A Remarkably Luminous Galaxy at z=11.1 Measured with Hubble Space Telescope Grism Spectroscopy

    Oesch, P A; van Dokkum, P G; Illingworth, G D; Bouwens, R J; Labbe, I; Franx, M; Momcheva, I; Ashby, M L N; Fazio, G G; Gonzalez, V; Holden, B; Magee, D; Skelton, R E; Smit, R; Spitler, L R; Trenti, M; Willner, S P


    We present Hubble WFC3/IR slitless grism spectra of a remarkably bright $z\\gtrsim10$ galaxy candidate, GN-z11, identified initially from CANDELS/GOODS-N imaging data. A significant spectroscopic continuum break is detected at $\\lambda=1.47\\pm0.01~\\mu$m. The new grism data, combined with the photometric data, rule out all plausible lower redshift solutions for this source. The only viable solution is that this continuum break is the Ly$\\alpha$ break redshifted to ${z_\\mathrm{grism}=11.09^{+0.08}_{-0.12}}$, just $\\sim$400 Myr after the Big Bang. This observation extends the current spectroscopic frontier by 150 Myr to well before the Planck (instantaneous) cosmic reionization peak at z~8.8, demonstrating that galaxy build-up was well underway early in the reionization epoch at z>10. GN-z11 is remarkably and unexpectedly luminous for a galaxy at such an early time: its UV luminosity is 3x larger than L* measured at z~6-8. The Spitzer IRAC detections up to 4.5 $\\mu$m of this galaxy are consistent with a stellar m...

  15. Remarkable magnetism and ferromagnetic coupling in semi-sulfuretted transition-metal dichalcogenides.

    Zhou, Yungang; Yang, Chengfei; Xiang, Xia; Zu, Xiaotao


    Motivated by recent investigations of semi-decorated two dimensional honeycomb structures, we demonstrated, via spin-polarized molecular-dynamics simulations and density-functional-theory calculations, that semi-sulfuretted transition-metal dichalcogenides of MX type (M = V, Nb, Ta; X = S, Se, Te) are stable and display remarkable magnetism. The unpaired d electron of the transition-metal atom arising from the breakage of the M-X bond is the mechanism behind the induction of the magnetism. The remarkable magnetism of the transition-metal atoms is caused by ferromagnetic coupling due to the competitive effects of through-bond interactions and through-space interactions. This implies the existence of an infinite ferromagnetic sheet with structural integrity and magnetic homogeneity. The estimated Curie temperatures suggest that the ferromagnetism can be achieved above room temperature in the VS, VSe, VTe, NbTe and TaTe sheets. Depending on the species of the M and X atoms, the MX sheet can be a magnetic metal, magnetic semiconductor or half-metal. Furthermore, in contrary to the recently reported semi-hydrogenated and semi-fluorinated layered materials consisting of B, C, N, etc., the MX sheets with many unpaired d electrons can offer a much stronger spin polarization and possess a more stable ferromagnetic coupling, which is critical for practical nanoscale device applications.

  16. Comprehension of direct and indirect sarcastic remarks in children and adolescents with Tourette's syndrome.

    Drury, Helena; Shah, Shivani; Stern, Jeremy S; Crawford, Sarah; Channon, Shelley


    Previous research has reported that aspects of social cognition such as nonliteral language comprehension are impaired in adults with Tourette's syndrome (TS), but little is known about social cognition in children and adolescents with TS. The present study aims to evaluate a measure of sarcasm comprehension suitable for use with children and adolescents (Experiment 1), and to examine sarcasm comprehension in children and adolescents with TS-alone or TS and attention deficit hyperactivity disorder (ADHD; Experiment 2). In Experiment 1, the measure of sarcasm comprehension was found to be sensitive to differences in nonliteral language comprehension for typically-developing children aged 10 to 11 years old compared to children aged 8 to 9 years old; the older group performed significantly better on the comprehension of scenarios ending with either direct or indirect sarcastic remarks, whereas the two age groups did not differ on the comprehension of scenarios ending with sincere remarks. In Experiment 2, both the TS-alone and TS+ADHD groups performed below the level of the control participants on the comprehension of indirect sarcasm items but not on the comprehension of direct sarcasm items and sincere items. Those with TS+ADHD also performed below the level of the control participants on measures of interference control and fluency. The findings are discussed with reference to the possible contribution of executive functioning and mentalizing to the patterns of performance.

  17. Eudragit E100 as a drug carrier: the remarkable affinity of phosphate ester for dimethylamine.

    Guzmán, M L; Manzo, R H; Olivera, M E


    Therapeutic agents containing phosphate groups in their molecules have increasing therapeutic impact. The object of this study was to characterize the cationic polyelectrolyte Eudragit E100 (EuE100) as a carrier for drugs containing phosphate groups, using dexamethasone phosphate (DP) as a model. A series of EuE100-DP complexes was obtained by acid-base reaction in which DP neutralized 12.5-75% of the basic groups of EuE100. The solids obtained after solvent evaporation revealed by spectroscopic characterization the complete reaction between the components through the ionic interaction between the amine groups of EuE100 and the phosphate groups of DP. The reversibility of the counterion condensation, evaluated through the proton-withdrawing effect produced by the ionic exchange generated by titration with NaCl, showed a remarkable high affinity between EuE100 and DP. In line, drug delivery in bicompartimental Franz cells toward water as receptor medium was very slow (2% in 6 h). However, it was increased as water was replaced by NaCl solution, which upon diffusion generates ionic exchange. A sustained release of DP with noticeable zero order kinetics accounted for a remarkable high affinity, mainly due to the electrostatic attraction. The release rate remains constant regardless of the saline concentration of the media. Besides, the delivery control is maintained even in gastric simulated fluid, a property not informed previously for EuE100 complexes.

  18. The remarkable convergence of skull shape in crocodilians and toothed whales.

    McCurry, Matthew R; Evans, Alistair R; Fitzgerald, Erich M G; Adams, Justin W; Clausen, Philip D; McHenry, Colin R


    The striking resemblance of long-snouted aquatic mammals and reptiles has long been considered an example of morphological convergence, yet the true cause of this similarity remains untested. We addressed this deficit through three-dimensional morphometric analysis of the full diversity of crocodilian and toothed whale (Odontoceti) skull shapes. Our focus on biomechanically important aspects of shape allowed us to overcome difficulties involved in comparing mammals and reptiles, which have fundamental differences in the number and position of skull bones. We examined whether diet, habitat and prey size correlated with skull shape using phylogenetically informed statistical procedures. Crocodilians and toothed whales have a similar range of skull shapes, varying from extremely short and broad to extremely elongate. This spectrum of shapes represented more of the total variation in our dataset than between phylogenetic groups. The most elongate species (river dolphins and gharials) are extremely convergent in skull shape, clustering outside of the range of the other taxa. Our results suggest the remarkable convergence between long-snouted river dolphins and gharials is driven by diet rather than physical factors intrinsic to riverine environments. Despite diverging approximately 288 million years ago, crocodilians and odontocetes have evolved a remarkably similar morphological solution to feeding on similar prey. © 2017 The Author(s).

  19. Rh(I)-Catalyzed 1,4-Conjugate Addition of Alkenylboronic Acids to a Cyclopentenone Useful for the Synthesis of Prostaglandins.

    Syu, Jin-Fong; Wang, Yun-Ting; Liu, Kung-Cheng; Wu, Ping-Yu; Henschke, Julian P; Wu, Hsyueh-Liang


    An efficient and trans-diastereoselective Rh(I)-catalyzed 1,4-conjugate addition reaction of alkenylboronic acids and a homochiral (R)-4-silyloxycyclopentenone useful for the synthesis of derivatives of prostaglandins E and F is described for the first time. The reaction functions under mild conditions and is particularly rapid (≤6 h) under low power (50 W) microwave irradiation at 30 °C in MeOH in the presence of a catalytic amount of KOH. Under these conditions, 3 mol % of [RhCl(COD)]2 is typically required to produce high yields. The method also functions without microwave irradiation at 3 °C in the presence of a stoichiometric amount of KOH. Under these conditions, only 1.5 mol % of [RhCl(COD)]2 is needed, but the reaction is considerably slower. The method accepts a range of aryl- and alkyl-substituted alkenylboronic acids, and its utility has been demonstrated by the synthesis of PGF2α (dinoprost) and tafluprost.

  20. New chiral phosphinephosphinite ligands: Application to stereoselective synthesis of a key intermediate of 1{beta}-methyl carbapenems by Rh(I)-catalyzed asymmetric hydroformylation

    Saito, Takao; Yoshida, Akifumi; Matsumura, Kazuhiko [Takasago International Corp., Kanagawa (Japan)] [and others


    Transition metal catalyzed asymmetric hydroformylation is an attractive and highly useful homologation process for organic synthesis. Recently, the authors reported that the Rh(I) complexes of phosphinephosphite BINAPHOS are highly efficient catalysts for enantioselective hydroformylation of a variety of olefins. This time, the authors have designed and synthesized new chiral phosphinephosphinite ligands having binaphthyl backbone, (R)-2-diarylphosphino-2{prime}-diarylphosphinoxy-1,1{prime}-binaphthy1 (hereafter abbreviated (R)-BIPNITE). The Rh(I) complexes of these ligands are effective catalysts for the asymmetric hydroformylation of 4-vinylazetidin-2-one to give the corresponding oxo-aldehyde 3{beta} as the major product in very high diastereoselectivities and in good regioselectivities. Interestingly, modifications of the aryl substituents in phosphine and phosphinite moieties afforded higher selectivities. Aldehyde 3{beta} was easily oxidized with NaClO{sub 2} to 4, a key intermediate of 1{beta}-methyl carbapenems. Thus, the present method provides a new practical route to a versatile key intermediate for the synthesis of carbapenem antibiotics.

  1. Zinc Oxide Nanoparticles for Revolutionizing Agriculture: Synthesis and Applications

    Sidra Sabir


    Full Text Available Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles.

  2. Note: Continuous synthesis of uniform vertical graphene on cylindrical surfaces.

    Bo, Zheng; Cui, Shumao; Yu, Kehan; Lu, Ganhua; Mao, Shun; Chen, Junhong


    This note describes a new reactor design for continuous synthesis of vertically oriented graphene (VG) sheets on cylindrical wire substrates using an atmospheric plasma-enhanced chemical vapor deposition (PECVD) system. Through combining a U-shaped reactor design with "dynamic mode" synthesis featuring simultaneous rotational and axial movements of the metallic wire substrate, the new setup can enable continuous synthesis of VG sheets on the wire surface with remarkable uniformity in both circumferential and axial directions. In contrast, synthesis of VG at "static mode" with a fixed substrate can only lead to non-uniform growth of VG sheets on the wire surface. Potential applications of the resulting uniform-VG-coated metallic wire could include field emitters, field-ionization-based neutral atom detectors, and indoor corona discharges.

  3. Isoselenocyanates: A Powerful Tool for the Synthesis of Selenium-Containing Heterocycles

    Hideharu Ishihara


    Full Text Available Selenium-containingheterocyclic compounds have been well recognized, not only because of their remarkable reactivities and chemical properties, but also because of their diverse pharmaceutical applications. In this context, isoselenocyanates have been emerged as a powerful tool for the synthesis of selenium-containing heterocycles, since they are easy to prepare and store and are safe to handle. In this review the recent advances in the development of synthesis methods forselenium-containing heterocycles from isoselenocyanates are presented and discussed.

  4. Highly regio- and diastereoselective, acidic clay supported intramolecular nitrile oxide-alkene cycloaddition on D-ribose derived nitriles: an efficient synthetic route to isoxazoline fused five and six membered carbocycles.

    Panda, Amarendra; Das, Sulagna; Pal, Shantanu


    An efficient synthetic route to isoxazoline fused carbocycles from carbohydrate scaffolds that comprise of free hydroxyl group(s) is described with high regio- and stereoselectivity. Montmorillonite K-10/chloramine T oxidation and in situ intramolecular nitrile oxide-alkene cycloaddition (INOC) of D-ribose derived oximes have been developed for the diversity oriented synthesis of isoxazoline fused five and six membered carbocycles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Quarkonium production at the LHC: A data-driven analysis of remarkably simple experimental patterns

    Faccioli, Pietro; Lourenço, Carlos; Araújo, Mariana; Knünz, Valentin; Krätschmer, Ilse; Seixas, João


    The LHC quarkonium production data reveal a startling observation: the J / ψ, ψ (2S), χc1, χc2 and ϒ (nS)pT-differential cross sections in the central rapidity region are compatible with one universal momentum scaling pattern. Considering also the absence of strong polarizations of directly and indirectly produced S-wave mesons, we conclude that there is currently no evidence of a dependence of the partonic production mechanisms on the quantum numbers and mass of the final state. The experimental observations supporting this universal production scenario are remarkably significant, as shown by a new analysis approach, unbiased by specific theoretical calculations of partonic cross sections, which are only considered a posteriori, in comparisons with the data-driven results.

  6. Remarkable magnetic enhancement of type-M hexaferrite of barium in polystyrene polymer

    Adly H. El-Sayed


    Full Text Available We demonstrate that the promising effect of inclusion of single magnetic-domain type-M hexaferrite of barium (BaM particles in polystyrene (PS polymer (BaM/PS weight ratio = 2/1. The results show that the coercivity of BaM particles remarkably increases from 714 to 3772 Oe and remanence increases from 2.07 to 5.41 emu.g−1 when they embedded into PS. Moreover, magnetic coercivity and squareness of the BaM-PS are significantly larger, and is comparable with corresponding values of other BaM-polymer composites. Therefore, BaM-PS composite enforce itself as the modern potential materials with tendency of replacing existing composite materials in several applications.

  7. Closing remarks on Faraday Discussion 107: Interactions of acoustic waves with thin films and interfaces

    Martin, S.J.


    The papers in this Faraday Discussion represent the state-of-the-art in using acoustic devices to measure the properties of thin films and interfaces. Sauerbrey first showed that the mass sensitivity of a quartz crystal could be used to measure the thickness of vacuum-deposited metals. Since then, significant progress has been made in understanding other interaction mechanisms between acoustic devices and contacting media. Bruckenstein and Shay and Kanazawa and Gordon showed that quartz resonators could be operated in a fluid to measure surface mass accumulation and fluid properties. The increased understanding of interactions between acoustic devices and contacting media has allowed new information to be obtained about thin films and interfaces. These closing remarks will summarize the current state of using acoustic techniques to probe thin films and interfaces, describe the progress reported in this Faraday Discussion, and outline some remaining problems. Progress includes new measurement techniques, novel devices, new applications, and improved modeling and data analysis.

  8. Concluding Remarks: The Current Status and Future Prospects for GRB Astronomy

    Gehrels, Neil


    We are in a remarkable period of discovery in GRB astronomy. The current satellites including Swift, Fermi. AGILE and INTEGRAL are detecting and observing bursts of all varieties. Increasing capabilities for follow-up observations on the ground and in space are leading to rapid and deep coverage across the electromagnetic spectrum, The future will see continued operation of the current experiments and with future missions like SVOM plus possible rni_Ssions like JANUS and EXIST. An exciting expansion of capabilities is occurring in areas of gravitational waves and neutrinos that could open new windows on the GRB phenomenon. Increased IR capabilities on the ground and with missions like JWST will enable further exploration of high redshift bursts. The future is bright.

  9. Glycine hydrogen fluoride: Remarkable hydrogen bonding in the dimeric glycine glycinium cation

    Fleck, M.; Ghazaryan, V. V.; Petrosyan, A. M.


    Crystals of glycine hydrogen fluoride (Gly·HF) were prepared from an aqueous solution containing stoichiometric quantities of the components. The crystal structure of Gly·HF was determined, IR and Raman spectra were registered and are discussed. Gly·HF crystallizes in the orthorhombic space group Pbca with Z = 32. The most remarkable feature of the structure is the existence of symmetric dimeric glycine-glycinium cations with short hydrogen bonds (O⋯O distance of 2.446 Å), charge-counterbalanced by hydrogen bifluoride (F sbnd H⋯F) - anions - in addition to the expected glycinium cations and fluoride anions. These results were compared with previously published data on crystals grown in the system glycine-HF-H 2O.

  10. Self-study program on HTML browser--application to Clinical Nursing General Remarks Course.

    Ochiai, N; Sota, Y; Ezumi, H


    We created a self-study program using HTML browser on the Clinical Nursing General Remarks Course, Eighty-three students each selected a published book on a personal history (written personal reflections from individuals who had undergone medical treatment and hospitalization), read it and submitted reports of their impressions of the histories. Their reports were arranged from a nursing perspective and entered on the home page of our college using HTML browser. We intended that the students would become more interested in reading of the personal histories, and that they would acquire new self-study skills and increase their interest in Internet through use of our program. In addition, we hoped that this program would encourage positive communication and mutual sharing of information. The students were able to easily refer to a personal history according to their interest from a nursing perspective. Therefore this program realized the mutual learning among students and other users.

  11. Durations of extended mental rehearsals are remarkably reproducible in higher level human performances.

    Brothers, L; Shaw, G L; Wright, E L


    It has been extremely difficult to quantify temporal aspects of higher level human brain function. We have found that mental rehearsals of musical performance of several minutes duration provide such a measure in that they can be highly reproducible, varying to less than 1%. These remarkable results pose fundamental neurophysiological problems. It is necessary to understand the underlying neuronal bases for this accuracy in the spatial-temporal activity of billions of neurons over minutes without sensory input. Further, they present a powerful constraint on neuronal models of brain function. Such highly reproducible (in duration) mental rehearsals might be used in conjunction with multielectrode EEG recordings to look for reproducible spatial-temporal patterns. Further, we suggest that our results may provide an extremely useful behavioural correlate for high level performance.

  12. Carbon nanocages: a new support material for Pt catalyst with remarkably high durability.

    Wang, Xiao Xia; Tan, Zhe Hua; Zeng, Min; Wang, Jian Nong


    Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for "real world" application.

  13. A database approach to information retrieval: The remarkable relationship between language models and region models

    Hiemstra, Djoerd


    In this report, we unify two quite distinct approaches to information retrieval: region models and language models. Region models were developed for structured document retrieval. They provide a well-defined behaviour as well as a simple query language that allows application developers to rapidly develop applications. Language models are particularly useful to reason about the ranking of search results, and for developing new ranking approaches. The unified model allows application developers to define complex language modeling approaches as logical queries on a textual database. We show a remarkable one-to-one relationship between region queries and the language models they represent for a wide variety of applications: simple ad-hoc search, cross-language retrieval, video retrieval, and web search.

  14. Concluding Remarks: The Current Status and Future Prospects for GRB Astronomy

    Gehrels, Neil


    We are in a remarkable period of discovery in GRB astronomy. The current satellites including Swift, Fermi. AGILE and INTEGRAL are detecting and observing bursts of all varieties. Increasing capabilities for follow-up observations on the ground and in space are leading to rapid and deep coverage across the electromagnetic spectrum, The future will see continued operation of the current experiments and with future missions like SVOM plus possible rni_Ssions like JANUS and EXIST. An exciting expansion of capabilities is occurring in areas of gravitational waves and neutrinos that could open new windows on the GRB phenomenon. Increased IR capabilities on the ground and with missions like JWST will enable further exploration of high redshift bursts. The future is bright.

  15. Bacteriocin-like substance from Bacillus amyloliquefaciens shows remarkable inhibition of Acanthamoeba polyphaga.

    Benitez, Lisianne Brittes; Caumo, Karin; Brandelli, Adriano; Rott, Marilise Brittes


    The effectiveness of a bacteriocin-like substance (BLS) produced by Bacillus amyloliquefaciens was tested against Acanthamoeba polyphaga strains, and its cytotoxic potential on Vero cells was investigated. Amebicidal activity of the purified BLS was tested by plate bioassays with concentrations ranging from 12.5 to 6,400 AU mL(-1). Damage to A. pholyphaga cells was monitored using an inverted microscope and counted in a Fuchs-Rosenthal chamber after 24, 48, and 72 h. According to the results obtained, the BLS showed remarkable amebicidal and amebostatic effect on A. polyphaga and showed no cytotoxicity on the Vero cells. These results may have great relevance in the development of new acanthamoebicidal compounds.

  16. On the Motivation and Foundation of Natural Time Analysis: Useful Remarks

    Varotsos Panayiotis A.


    Full Text Available Since its introduction in 2001, natural time analysis has been applied to diverse fields with remarkable results. Its validity has not been doubted by any publication to date. Here, we indicate that frequently asked questions on the motivation and the foundation of natural time analysis are directly answered if one takes into account the following two key points that we have considered as widely accepted when natural time analysis was proposed: first, the aspects on the energy of a system forwarded by Max Planck in his Treatise on Thermodynamics; second, the theorem on the characteristic functions of probability distributions which Gauss called Ein Schönes Theorem der Wahrscheinlichkeitsrechnung (beautiful theorem of probability calculus. The case of the time series of earthquakes and of the precursory Seismic Electric Signals are discussed as typical examples.

  17. Remarkable effect of chalcogen substitution on an enzyme mimetic for deiodination of thyroid hormones.

    Raja, Karuppusamy; Mugesh, Govindasamy


    Iodothyronine deiodinases are selenoenzymes which regulate the thyroid hormone homeostasis by catalyzing the regioselective deiodination of thyroxine (T4). Synthetic deiodinase mimetics are important not only to understand the mechanism of enzyme catalysis, but also to develop therapeutic agents as abnormal thyroid hormone levels have implications in different diseases, such as hypoxia, myocardial infarction, critical illness, neuronal ischemia, tissue injury, and cancer. Described herein is that the replacement of sulfur/selenium atoms in a series of deiodinase mimetics by tellurium remarkably alters the reactivity as well as regioselectivity toward T4. The tellurium compounds reported in this paper represent the first examples of deiodinase mimetics which mediate sequential deiodination of T4 to produce all the hormone derivatives including T0 under physiologically relevant conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Integrity assessment of pipelines - additional remarks; Avaliacao da integridade de dutos - observacoes adicionais

    Alves, Luis F.C. [PETROBRAS S.A., Salvador, BA (Brazil). Unidade de Negocios. Exploracao e Producao


    Integrity assessment of pipelines is part of a process that aims to enhance the operating safety of pipelines. During this task, questions related to the interpretation of inspection reports and the way of regarding the impact of several parameters on the pipeline integrity normally come up. In order to satisfactorily answer such questions, the integrity assessment team must be able to suitably approach different subjects such as corrosion control and monitoring, assessment of metal loss and geometric anomalies, and third party activities. This paper presents additional remarks on some of these questions based on the integrity assessment of almost fifty pipelines that has been done at PETROBRAS/E and P Bahia over the past eight years. (author)

  19. Biomimetic "water strider leg" with highly refined nanogroove structure and remarkable water-repellent performance.

    Bai, Fan; Wu, Juntao; Gong, Guangming; Guo, Lin


    The water strider is a wonderful case that we can learn from nature to understand how to stride on the water surface. Inspired by the unique hierarchical micro/nanostructure of the water strider leg, in this article, we designed and fabricated an artificial strider leg with refined nanogroove structure by using an electrospinning and sacrificial template method. A model water strider that was equipped with four artificial legs showed remarkable water-repellent performance; namely, it could carry a load that was about 7 times heavier than its own weight. Characterization demonstrated that, even though the artificial leg did not possess a superhydrophobic surface, the numerous nanogrooves could still provide a huge supporting force for the man-made model strider. This work enlightens the development of artificial water-walking devices for exploring and monitoring the surface of water. Because of the advances of the applied materials, the devices may fulfill tasks in a harsh aquatic environment.

  20. Thiamin Pyrimidine Biosynthesis in Candida albicans: A Remarkable Reaction between Histidine and Pyridoxal Phosphate

    Lai, Rung-Yi; Huang, Siyu; Fenwick, Michael K.; Hazra, Amrita; Zhang, Yang; Rajashankar, Kanagalaghatta; Philmus, Benjamin; Kinsland, Cynthia; Sanders, Jennie Mansell; Ealick, Steven E.; Begley, Tadhg P. (Cornell); (TAM)


    In Saccharomyces cerevisiae, thiamin pyrimidine is formed from histidine and pyridoxal phosphate (PLP). The origin of all of the pyrimidine atoms has been previously determined using labeling studies and suggests that the pyrimidine is formed using remarkable chemistry that is without chemical or biochemical precedent. Here we report the overexpression of the closely related Candida albicans pyrimidine synthase (THI5p) and the reconstitution and preliminary characterization of the enzymatic activity. A structure of the C. albicans THI5p shows PLP bound at the active site via an imine with Lys62 and His66 in close proximity to the PLP. Our data suggest that His66 of the THI5 protein is the histidine source for pyrimidine formation and that the pyrimidine synthase is a single-turnover enzyme.

  1. Trieste conference on digital microelectronics and microprocessors in particle physics: Summary and concluding remarks

    Nash, T.


    This paper is a written version of the Concluding Remarks presented at the International Conference on the Impact of Digital Microelectronics and Microprocessors on Particle Physics. The Conference emphasized on-line data acquisition and triggering problems in high energy physics. Among the participants there was a clearly growing consensus that as these real time systems become larger they require more attention from the beginning to overall system coherence and manageability issues. We consider what this means for SSC/LHC era detectors. Given the interesting results on pixel silicon, neural networks, and parallel microprocessor based computers presented at Trieste, we speculate on some surprisingly simple, though still very radical, ideas on systems solutions for those huge detectors.

  2. Case of parotid tumor showing remarkable regression following hyperthermo-chemo-radiotherapy

    Fujimura, T.; Yonemura, Y.; Kamata, T.


    A 72-year-old woman developed adenocarcinoma of the left parotid gland. Because of the excessive size of her tumor and the fact that she suffered from severe liver dysfunction, she was treated by hyperthermo-chemo-radiotherapy (HCR therapy). After ten sessions of radiofrequency hyperthermia with HEH 500 (13.56 MHz radiofrequency wave), 50-Gy irradiation from a linac and administration of 33.0 g of tegafur in suppository form, the tumor mass showed remarkable regression decreasing in size by as much as 84 % on computed tomography. Histologically, the tumor which was resected under local anesthesia, showed almost total necrosis. The multidisciplinary HCR therapy was well tolerated and effective as a therapy for cancer in this case.

  3. A remarkably stable kissing-loop interaction defines substrate recognition by the Neurospora Varkud Satellite ribozyme.

    Bouchard, Patricia; Legault, Pascale


    Kissing loops are tertiary structure elements that often play key roles in functional RNAs. In the Neurospora VS ribozyme, a kissing-loop interaction between the stem-loop I (SLI) substrate and stem-loop V (SLV) of the catalytic domain is known to play an important role in substrate recognition. In addition, this I/V kissing-loop interaction is associated with a helix shift in SLI that activates the substrate for catalysis. To better understand the role of this kissing-loop interaction in substrate recognition and activation by the VS ribozyme, we performed a thermodynamic characterization by isothermal titration calorimetry using isolated SLI and SLV stem-loops. We demonstrate that preshifted SLI variants have higher affinity for SLV than shiftable SLI variants, with an energetic cost of 1.8-3 kcal/mol for the helix shift in SLI. The affinity of the preshifted SLI for SLV is remarkably high, the interaction being more stable by 7-8 kcal/mol than predicted for a comparable duplex containing three Watson-Crick base pairs. The structural basis of this remarkable stability is discussed in light of previous NMR studies. Comparative thermodynamic studies reveal that kissing-loop complexes containing 6-7 Watson-Crick base pairs are as stable as predicted from comparable RNA duplexes; however, those with 2-3 Watson-Crick base pairs are more stable than predicted. Interestingly, the stability of SLI/ribozyme complexes is similar to that of SLI/SLV complexes. Thus, the I/V kissing loop interaction represents the predominant energetic contribution to substrate recognition by the trans-cleaving VS ribozyme. © 2014 Bouchard and Legault; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  4. Synthesis of Bimetallic Platinum Nanoparticles for Biosensors

    Gerard M. Leteba


    Full Text Available The use of magnetic nanomaterials in biosensing applications is growing as a consequence of their remarkable properties; but controlling the composition and shape of metallic nanoalloys is problematic when more than one precursor is required for wet chemistry synthesis. We have developed a successful simultaneous reduction method for preparation of near-spherical platinum-based nanoalloys containing magnetic solutes. We avoided particular difficulties in preparing platinum nanoalloys containing Ni, Co and Fe by the identification of appropriate synthesis temperatures and chemistry. We used transmission electron microscopy (TEM to show that our particles have a narrow size distribution, uniform size and morphology, and good crystallinity in the as-synthesized condition. Energy dispersive spectroscopy (EDS and X-ray diffraction (XRD confirms the coexistence of Pt with the magnetic solute in a face-centered cubic (FCC solid solution.

  5. Some remarks on the genus Echinogammarus Stebbing, 1899 with description of a new species E. valedictus from Algeria (Crustacea, Amphipoda)

    Pinkster, Sjouk; Platvoet, Dirk


    Some short remarks are made on taxonomic problems in the genus Echinogammarus and a description is given of a new species from mountain streams in Algeria, characterized by a onesegmented exopodite in uropod 3.

  6. Some remarks on the genus Echinogammarus Stebbing, 1899 with description of a new species E. valedictus from Algeria (Crustacea, Amphipoda)

    Pinkster, Sjouk; Platvoet, Dirk


    Some short remarks are made on taxonomic problems in the genus Echinogammarus and a description is given of a new species from mountain streams in Algeria, characterized by a onesegmented exopodite in uropod 3.

  7. A Four‐Component Reaction for the Synthesis of Dioxadiazaborocines

    Flagstad, Thomas; Petersen, Mette Terp; Nielsen, Thomas E.


    A four‐component reaction for the synthesis of heterocyclic boronates is reported. Readily available hydrazides, α‐hydroxy aldehydes, and two orthogonally reactive boronic acids are combined in a single step to give structurally distinct bicyclic boronates, termed dioxadiazaborocines (DODA boroci...... borocines). In this remarkable process, one boronic acid reacts as a carbon nucleophile and the other as a boron electrophile to provide enantio‐ and diastereomerically pure heterocyclic boronates with multiple stereocenters in high yields....

  8. The remarkable increasement of maysin and maysin derivatives contents from Eremochloa ophiuroides by various stresses

    Lee, Eun Mi; Lee, Seung Sik; Hong, Sung Hyun; Chung, Byung Yeoup [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, Jae Young [Chonbuk National University, Jeonju (Korea, Republic of); Lee, In Chul [Youngdong University, Youngdong (Korea, Republic of)


    Centipedegrass belonging to the genus Eremochloa (Poaceae) consisted of eight species native to China and Southeast Asia and became one of the most popular lawn grasses in South America. Maysin, flavone C-glucoside, in centipedegrass reported antibiotic to resistance to fall armyworm (FAW: Spodoptera frugiperda). Until now, maysin found in the maize silk, teosinte, and centipedegrass. These plants contained an infinitesimal amount of maysin, in addition, maysin was not able to obtain by chemical synthesis. Therefore, it could be named enough that maysin was the world premium natural compound. To synthesis maysin in vivo, precursors like luteolin, isoorientin, and rhamnoslyisoorientin was required. The investigation on maysin and maysin derivatives have been carried out very limitedly because maysin and maysin derivaeives were not able to synthesize chemically and the rote for obtaining these compounds was very limited. Therefore, the aim of present study was to investigate the methods for obtaining higher yields of maysin and its derivatives from centipedegrass using various stress sources such as gamma-ray, UV-B, and wounding (folding)

  9. A remarkably stable TipE gene cluster: evolution of insect Para sodium channel auxiliary subunits

    Li Jia


    Full Text Available Abstract Background First identified in fruit flies with temperature-sensitive paralysis phenotypes, the Drosophila melanogaster TipE locus encodes four voltage-gated sodium (NaV channel auxiliary subunits. This cluster of TipE-like genes on chromosome 3L, and a fifth family member on chromosome 3R, are important for the optional expression and functionality of the Para NaV channel but appear quite distinct from auxiliary subunits in vertebrates. Here, we exploited available arthropod genomic resources to trace the origin of TipE-like genes by mapping their evolutionary histories and examining their genomic architectures. Results We identified a remarkably conserved synteny block of TipE-like orthologues with well-maintained local gene arrangements from 21 insect species. Homologues in the water flea, Daphnia pulex, suggest an ancestral pancrustacean repertoire of four TipE-like genes; a subsequent gene duplication may have generated functional redundancy allowing gene losses in the silk moth and mosquitoes. Intronic nesting of the insect TipE gene cluster probably occurred following the divergence from crustaceans, but in the flour beetle and silk moth genomes the clusters apparently escaped from nesting. Across Pancrustacea, TipE gene family members have experienced intronic nesting, escape from nesting, retrotransposition, translocation, and gene loss events while generally maintaining their local gene neighbourhoods. D. melanogaster TipE-like genes exhibit coordinated spatial and temporal regulation of expression distinct from their host gene but well-correlated with their regulatory target, the Para NaV channel, suggesting that functional constraints may preserve the TipE gene cluster. We identified homology between TipE-like NaV channel regulators and vertebrate Slo-beta auxiliary subunits of big-conductance calcium-activated potassium (BKCa channels, which suggests that ion channel regulatory partners have evolved distinct lineage

  10. One-Pot Fabrication of Hollow and Porous Pd-Cu Alloy Nanospheres and Their Remarkably Improved Catalytic Performance for Hexavalent Chromium Reduction.

    Han, Shu-He; Bai, Juan; Liu, Hui-Min; Zeng, Jing-Hui; Jiang, Jia-Xing; Chen, Yu; Lee, Jong-Min


    Noble metal nanostructures (NMNSs) play a crucial role in many heterogeneous catalytic reactions. Hollow and porous NMNSs possess generally prominent advantages over their solid counterparts due to their unordinary structural features. In this work, we describe a facial one-pot synthesis of hollow and porous Pd-Cu alloy nanospheres (Pd-Cu HPANSs) through a polyethylenimine (PEI)-assisted oxidation-dissolution mechanism. The strong coordination interaction between Cu(II) and PEI facilitates the oxidation-dissolution of the Cu2O nanospheres template under air conditions, which is responsible for the generation of the Pd-Cu alloy and the convenient removal of the Cu2O nanospheres template at room temperature. Compared to the commercial Pd black, the Pd-Cu HPANSs show remarkably improved catalytic activity for the reduction of K2Cr2O7 by HCOOH at room temperature, attributing to the enhanced catalytic activity of the Pd-Cu HPANSs for the dehydrogenation decomposition of HCOOH.

  11. Palladium-catalyzed carbonylative synthesis of quinazolinones from 2-aminobenzamide and aryl bromides.

    Wu, Xiao-Feng; He, Lin; Neumann, Helfried; Beller, Matthias


    C from CO! A straightforward procedure for the carbonylative synthesis of quinazolinones from readily available 2-aminobenzamide and aryl bromides has been developed. In the presence of a palladium catalyst, various quinazolinones were produced in moderate to excellent yields. Remarkably, no chromatography was needed for purification (see scheme).

  12. Phenylboronic acid catalysed synthesis of 1,5-benzodiazepines via cyclocondensation of -phenylenediamine and ketones

    Santosh V Goswami; Prashant B Thorat; Sudhakar R Bhusare


    Phenylboronic acid has been found to be an efficient catalyst for the synthesis of 1,5-benzodiazepine derivatives via cyclocondensation of -phenylenediamine and various ketones in good to excellent yields (82-91%) using acetonitrile as solvent at reflux condition. The remarkable advantages offered by this method are easy mild reaction condition, experimental work up and good to excellent yields of products.

  13. Cascade Reaction and Synthesis of Bicyclo[2,2,2]octenones

    LI Nian-Guang; WANG Jin-Xin; YOU Qi-Dong; CHU Gang; GUO Qing-Long


    During study on the remarkable cascade reaction for synthesis of compound 1, the neo-caged scaffold 2 with a heterocyclic bicyclo[2.2.2]octenone moiety and two new aUyl substituted xanthones 3, 4 were obtained besides the known caged scaffold 1.The probable reaction processes were also elucidated in this paper.

  14. Recent Advances in Substrate-Controlled Asymmetric Cyclization for Natural Product Synthesis

    Jeyun Jo


    Full Text Available Asymmetric synthesis of naturally occurring diverse ring systems is an ongoing and challenging research topic. A large variety of remarkable reactions utilizing chiral substrates, auxiliaries, reagents, and catalysts have been intensively investigated. This review specifically describes recent advances in successful asymmetric cyclization reactions to generate cyclic architectures of various natural products in a substrate-controlled manner.

  15. Few remarks on the Higgs boson decays in gauge-Higgs unification

    Hasegawa, K.; Lim, C. S.


    In the scenario of gauge-Higgs unification, the origin of the Higgs boson is the higher-dimensional gauge boson. Very characteristic predictions are made of the Higgs boson interactions in this scenario, reflecting its origin. In particular, a remarkable claim has been made: the contribution of nonzero Kaluza-Klein modes to the Higgs decay H →Z γ exactly vanishes in the minimal SU(3) electroweak unified model, at least at the one-loop level. In this brief paper, in order to see whether this prediction is a general feature of the scenario or the consequence of the specific choice of the model, matter content, or the order of perturbative expansion, we perform an operator analysis. We demonstrate that no relevant operator exists, respecting the gauge symmetry SU(3) in the bulk. We also comment on the possibly important contribution to the photonic decay H →γ γ due to the nonzero Kaluza-Klein modes of light quarks.

  16. Interpreting the Bible in the 'new' South Africa: Remarks on some problems and challenges

    D. J. Human


    Full Text Available Interpreting the Bible in the 'new' South Africa DJ Human Department of Biblical Studies (Sec B University of Pretoria The Bible plays an important role in South African society. The interpretation of this book within or outside the Christian community has become an increaslingly major source of debate. It has been used and misused in several spheres of society. This article does not intend providing an extensive and composite picture of the problems and character of biblical hermeneutics. Nor will it attempt to elaborate on or explain the origins, development and influences of all the different her-meneutical approaches. Rather, it poses to be an introduction to a few of the problem(s encountered in the attempt to understand the Bible, especially in terms of the 'new' South Africa. Within the framework of this scope, remarks will be made regarding the challenges involved in interpreting the Bible, the role of the interpreter in the interpretation process, the varied forms of literature to be found in Scripture, and in the last instance, to take cognisance of a few methodological approaches to the text analysis of the Bible.

  17. Luhman 16AB: A Remarkable, Variable L/T Transition Binary 2 pc from the Sun

    Burgasser, A J; Beletsky, Y; Plavchan, P; Gillon, M; Radigan, J; Jehin, E; Delrez, L; Opitom, C; Morrell, N; Osten, R; Street, R; Melis, C; Triaud, A; Simcoe, R


    Luhman (2013) has reported the discovery of a brown dwarf binary system only 2.01+/-0.15 pc from the Sun. The binary is well-resolved with a projected separation of 1.5", and spectroscopic observations have identified the components as late-L and early-T dwarfs. The system exhibits several remarkable traits, including a "flux reversal", where the T dwarf is brighter over 0.9-1.3 micron but fainter at other wavelengths; and significant (~10%) short-period (~4.9 hr) photometric variability with a complex light curve. These observations suggest spatial variations in condensate cloud structure, which is known to evolve substantially across the L dwarf/T dwarf transition. Here we report preliminary results from a multi-site monitoring campaign aimed at probing the spectral and temporal properties of this source. Focusing on our spectroscopic observations, we report the first detections of NIR spectral variability, present detailed analysis of K I lines that confirm differences in condensate opacity between the com...

  18. Monitoring the Remarkable Radio Spectral-Line/Continuum Outburst in Galaxy NGC 660

    Salter, Christopher J.; Ghosh, Tapasi; Minchin, Robert F.; Momjian, Emmanuel


    A radio continuum and spectral-line outburst in galaxy NGC660 was serendipitously discovered by us at Arecibo in 2007/8. From Feb. 2013, roughly bi-monthly Arecibo spectral-line and continuum monitoring of this remarkable event has been performed, with 28 observing epochs completed to Auguast 2016. Variability of the continuum spectrum, and of the detailed OH emission/absorption spectra at 4660, 4750, and 4765 MHz have been followed over this period. The rapid changes seen in the molecular emission from the nuclear region of this galaxy are unprecedented. To delineate the physical model of this complicated starburst system further, we have supplemented this Arecibo monitoring by two epochs of milliarcsecond-resolution HSA line and continuum imaging, (with Arecibo in this VLBI array). The VLBI images reveal jet structure consistent with a recent nuclear outburst. The OH features show association with the outburst hotspots. Both the continuum and OH maser intensities have been steadily declining since peaking at mid-2011.

  19. Remark on "Algorithm 916: Computing the Faddeyeva and Voigt functions": Efficiency Improvements and Fortran Translation

    Zaghloul, Mofreh R


    This remark describes efficiency improvements to Algorithm 916 [Zaghloul and Ali 2011]. It is shown that the execution time required by the algorithm, when run at its highest accuracy, may be improved by more than a factor of two. A better accuracy vs efficiency trade off scheme is also implemented; this requires the user to supply the number of significant figures desired in the computed values as an extra input argument to the function. Using this trade-off, it is shown that the efficiency of the algorithm may be further improved significantly while maintaining reasonably accurate and safe results that are free of the pitfalls and complete loss of accuracy seen in other competitive techniques. The current version of the code is provided in Matlab and Scilab in addition to a Fortran translation prepared to meet the needs of real-world problems where very large numbers of function evaluations would require the use of a compiled language. To fulfill this last requirement, a recently proposed reformed version o...

  20. The Remarkable Afterglow of GRB 061007: Implications for Optical Flashes and GRB Fireballs

    Mundell, C G; Guidorzi, C; Kobayashi, S; Steele, I A; Malesani, D; Amati, L; D'Avanzo, P; Bersier, D F; Gomboc, A; Rol, E; Bode, M F; Carter, D; Mottram, C J; Monfardini, A; Smith, R J; Malhotra, S; Wang, J; Bannister, N; O'Brien, P T; Tanvir, N R


    We present a multiwavelength analysis of Swift GRB 061007. The 2-m robotic Faulkes Telescope South (FTS) began observing 137 s after the onset of the gamma-ray emission, when the optical counterpart was already decaying from R~10.3 mag, and continued observing for the next 5.5 hours. These observations begin during the final gamma-ray flare and continue through and beyond a long, soft tail of gamma-ray emission whose flux shows an underlying simple power law decay identical to that seen at optical and X-ray wavelengths, with temporal slope alpha~1.7. This remarkably simple decay in all of these bands is rare for Swift bursts, which often show much more complex light curves. We suggest the afterglow emission begins as early as 30-100 s and is contemporaneous with the on-going variable prompt emission from the central engine, but originates from a physically distinct region dominated by the forward shock. The afterglow continues unabated until at least ~10^5 seconds showing no evidence of a break. The observed ...

  1. New URJC-1 Material with Remarkable Stability and Acid-Base Catalytic Properties

    Pedro Leo


    Full Text Available Emerging new metal-organic structures with tunable physicochemical properties is an exciting research field for diverse applications. In this work, a novel metal-organic framework Cu(HIT(DMF0.5, named URJC-1, with a three-dimensional non-interpenetrated utp topological network, has been synthesized. This material exhibits a microporous structure with unsaturated copper centers and imidazole–tetrazole linkages that provide accessible Lewis acid/base sites. These features make URJC-1 an exceptional candidate for catalytic application in acid and base reactions of interest in fine chemistry. The URJC-1 material also displays a noteworthy thermal and chemical stability in different organic solvents of different polarity and boiling water. Its catalytic activity was evaluated in acid-catalyzed Friedel–Crafts acylation of anisole with acetyl chloride and base-catalyzed Knoevenagel condensation of benzaldehyde with malononitrile. In both cases, URJC-1 material showed very good performance, better than other metal organic frameworks and conventional catalysts. In addition, a remarkable structural stability was proven after several consecutive reaction cycles.

  2. A Multi-band Study of the Remarkable Jet in Quasar 4C+19.44

    Harris, D. E.; Lee, N. P.; Schwartz, D. A.; Siemiginowska, A.; Massaro, F.; Birkinshaw, M.; Worrall, D. M.; Cheung, C. C.; Gelbord, J. M.; Jorstad, Svetlana G.; Marscher, Alan P.; Landt, H.; Marshall, H.; Perlman, E. S.; Stawarz, L.; Uchiyama, Y.; Urry, C. M.


    We present arcsecond-resolution data in the radio, IR, optical, and X-ray for 4C+19.44 (=PKS 1354+195), the longest and straightest quasar jet with deep X-ray observations. We report results from radio images with half to one arcsecond angular resolution at three frequencies, plus Hubble Space Telescope and Spitzer data. The Chandra data allow us to measure the X-ray spectral index in 10 distinct regions along the 18″ jet and compare with the radio index. The radio and X-ray spectral indices of the jet regions are consistent with a value of α =0.80 throughout the jet, to within 2σ uncertainties. The X-ray jet structure to the south extends beyond the prominent radio jet and connects to the southern radio lobe, and there is extended X-ray emission, both in the direction of the unseen counter-jet, and also coincident with the northern radio lobe. This jet is remarkable because its straight appearance over a large distance allows the geometry factors to be taken as fixed along the jet. Using the model of inverse Compton scattering of the cosmic microwave background (iC/CMB) by relativistic electrons, we find that the magnetic field strengths and Doppler factors are relatively constant along the jet. If instead the X-rays are synchrotron emission, they must arise from a population of electrons distinct from the particles producing the radio synchrotron spectrum.

  3. Some remarks on the relevance of basic research in nursing inquiry.

    Lehtinen, Ullaliina; Ohlén, Joakim; Asplund, Kenneth


    The aim of this article was to illuminate the issue of basic research in nursing and to problematize its relevance for our discipline. First, we asked leading nursing scholars in the Nordic countries to share their views on basic research in nursing. Thereafter, the ideas, views and suggestions of the scholars were amalgamated with insights from the literature and from the discussions in our project team. Our two guiding questions were: What role can basic research be assigned? Which, if any, forms of basic research can be identified? We found that basic nursing research may be seen as a necessary basis for applied research, as a contribution to applied research, or that the whole issue is seen as a pseudo-issue. We further found that basic nursing research can be seen as either contextual or general as well as either intradisciplinary or multidisciplinary in form. We conclude by the following three succinct remarks or assertions: that basic nursing research is not to be equated with biomedical conceptions of basic research; that basic nursing research may take place on several theoretical levels; and finally, that an indiscriminate dismissal of basic research in nursing may affect the cognitive autonomy of our discipline.

  4. Campylobacter jejuni sequence types show remarkable spatial and temporal stability in Blackbirds

    Petra Griekspoor


    Full Text Available Background: The zoonotic bacterium Campylobacter jejuni has a broad host range but is especially associated with birds, both domestic and wild. Earlier studies have indicated thrushes of the genus Turdus in Europe to be frequently colonized with C. jejuni, and predominately with host-associated specific genotypes. The European Blackbird Turdus merula has a large distribution in Europe, including some oceanic islands, and was also introduced to Australia by European immigrants in the 1850s. Methods: The host specificity and temporal stability of European Blackbird C. jejuni was investigated with multilocus sequence typing in a set of isolates collected from Sweden, Australia, and The Azores. Results: Remarkably, we found that the Swedish, Australian, and Azorean isolates were genetically highly similar, despite extensive spatial and temporal isolation. This indicates adaptation, exquisite specificity, and stability in time for European Blackbirds, which is in sharp contrast with the high levels of recombination and mutation found in poultry-related C. jejuni genotypes. Conclusion: The maintenance of host-specific signals in spatially and temporally separated C. jejuni populations suggests the existence of strong purifying selection for this bacterium in European Blackbirds.

  5. Foramen Magnum Meningioma: Some Anatomical and Surgical Remarks through Five Cases.

    Mostofi, Keyvan


    Foramen magnum meningioma foramen magnum meningioma (FMM) represents 2% all of meningiomas. The clinical symptomatology is usually insidious and consists of headache, neck pain and hypoesthesia in C2 dermatome. Because of their location, the management is challenging. The purpose of this paper is to present our experience in the surgery of FMM. Since 1938, numerous series have been published but they are very heterogeneous with high variability of location and surgical approaches. During two years, we operated 5 patients with FMM. All the patients had magnetic resonance imaging (MRI) with angio-MRI to study the relationship between tumour and vertebral artery (VA). In all the cases, we used prone position. In one case, considering the tumour localization (posterior and pure intradural) the tumour was removed via a midline suboccipital approach with craniotomy and C1-C2 laminectomy. In all other cases, meningiomas were posterolateral (classification of George) with extradural extension in one case. In all cases, VA was surrounded by tumor. So, we opted for a modified postero-lateral approach with inverted L incision, craniotomy and C1-C2 laminectomy without resect occipital condyle. Epidural part of VA was identified and mobilized laterally. Once VA was identified we opened dura mater and began to remove the tumour. In this paper, we present five cases of operated FMM, describe our approaches, the reason of each approach and propose some surgical remarks.

  6. The theory of the rise of sap in trees: some historical and conceptual remarks

    Brown, Harvey R


    The ability of trees to suck water from roots to leaves, sometimes to heights of over a hundred meters, is remarkable given the absence of any mechanical pump. This study deals with a number of issues, of both an historical and conceptual nature, in the orthodox Cohesion Tension theory of the ascent of sap in trees. The theory relies chiefly on the exceptional cohesive and adhesive properties of water, the structural properties of trees, and the role of evaporation (transpiration) from leaves. But it is not the whole story. Plant scientists have been aware since the inception of the theory in the late 19th century that further processes are at work in order to prime the trees, the main such process (growth itself) being so obvious to them that it is often omitted from the story. Other factors depend largely on the type of tree, and are not always fully understood. For physicists, in particular, it may be helpful to see the fuller picture, which is what this study attempts to provide in nontechnical terms.

  7. Diversity in viral anti-PKR mechanisms: a remarkable case of evolutionary convergence.

    Elena Domingo-Gil

    Full Text Available Most viruses express during infection products that prevent or neutralize the effect of the host dsRNA activated protein kinase (PKR. Translation of Sindbis virus (SINV mRNA escapes to PKR activation and eIF2 phosphorylation in infected cells by a mechanism that requires a stem loop structure in viral 26S mRNA termed DLP to initiate translation in the absence of functional eIF2. Unlike the rest of viruses tested, we found that Alphavirus infection allowed a strong PKR activation and eIF2α phosphorylation in vitro and in infected animals so that the presence of DLP structure in mRNA was critical for translation and replication of SINV. Interestingly, infection of MEFs with some viruses that express PKR inhibitors prevented eIF2α phosphorylation after superinfection with SINV, suggesting that viral anti-PKR mechanisms could be exchangeable. Thus, translation of SINV mutant lacking the DLP structure (ΔDLP in 26S mRNA was partially rescued in cells expressing vaccinia virus (VV E3 protein, a known inhibitor of PKR. This case of heterotypic complementation among evolutionary distant viruses confirmed experimentally a remarkable case of convergent evolution in viral anti-PKR mechanisms. Our data reinforce the critical role of PKR in regulating virus-host interaction and reveal the versatility of viruses to find different solutions to solve the same conflict.

  8. Cold-rolled complex-phase steels: AHSS material with remarkable properties

    Hebesberger, T.; Pichler, A.; Walch, C.; Blaimschein, M. [voestalpine Stahl GmbH, Linz (Austria); Spiradek-Hahn, K. [ARC Seibersdorf Research GmbH (Austria)


    The reduction of the body-in-white weight, in combination with stiffness and crash safety improvements is of fundamental interest in the automotive industry. Therefore, several Advanced High Strength Steel (AHSS) grades have been developed in the last several years, whereby the main focus was laid on dual-phase (DP) and TRIP steels. Recently, a new high strength steel grade - complex-phase (CP) steels - is gaining more and more interest. In contrast to DP grades of similar strength level, CP grades have a significantly higher yield strength and thus a higher yield ratio. Although, CP grades reach lower elongation values in the tensile test, they show an excellent bendability and stretch-flangeability. Due to this remarkable balance between strength, bendability and stretch-flangeability, complex-phase steels are potential candidates for roll-formed parts and parts where sharp radii and/or a good formability of punched edges are required. Therefore, the microstructure, the processing, and the formability of CP grades are discussed in detail in this work. (orig.)

  9. A Few Observations and Remarks on Time Effectiveness of Interactive Electronic Testing

    Martin MAGDIN


    Full Text Available In the paper, we point out several observations and remarks on time effectiveness of electronic testing, in particular of its new form (interactive tests. A test is often used as an effective didactic tool for evaluating the extent of gained cognitive capabilities. According to authors Rudman (1989 and Wang (2003 it is provable that the relationship towards e-testing depends on the degree of previous experiences with this form of examination. Conducted experiments (not only by these authors show that students using the traditional testing form (putting answers down on a paper are happy to have the opportunity to use a computer for testing. The reason is the fact that they are usually used to a complete explanation of the educational content, frontal examination during the lesson and also in the course of the school year and more limited possibilities to use the Internet for educational purposes. Most of them do not even know about the possibilities of e-learning and electronic evaluation. On the other hand, the group of students who are being tested using the traditional form and at the same time using computers usually prefer the traditional form, while using multimedia tools is more or less normal to them.

  10. Eine außergewöhnliche Biographie A Remarkable Biography

    Andrea Rönz


    Full Text Available Erst im Alter von 44 Jahren, als ihre beiden Söhne erwachsen waren, begann die Wienerin Ida Pfeiffer Forschungsreisen zu unternehmen, die sie in den folgenden 16 Jahren zunächst ins Heilige Land und anschließend zweimal um die ganze Welt führen sollten. Die hierzu veröffentlichten Reiseberichte erfreuten sich beim zeitgenössischen Publikum großer Beliebtheit, die von den Reisen mitgebrachten Sammlungen stellten eine bedeutende Bereicherung für die Wissenschaft dar. Trotz dieser für die Mitte des 19. Jahrhunderts ungewöhnlichen weiblichen Biographie blieb Ida Pfeiffer dennoch in ihren Schriften eine Verfechterin der bürgerlichen Normen und Werte. Diesen widersprüchlichen Charakter zu beleuchten hat sich Gabriele Habinger zur Aufgabe gemacht.The Viennese born Ida Pfeiffer began undertaking research expeditions at the age of 44, after both of her sons were grown up. In the 16 years that followed, the trips led her first to the Holy Land and then finally two times around the world. The published travel reports were widely popular in the contemporary public and the collections brought back from the journeys constituted an enrichment for science. Despite this remarkable female biography for the mid-19th Century, in her writings Ida Pfeiffer remained a proponent for bourgeois morals and ideals. Gabriele Habinger made it her task to illuminate this contrasting character.

  11. M31N 2008-12a - The Remarkable Recurrent Nova in M31

    Darnley, M J


    M31N 2008-12a is a remarkable recurrent nova within the Andromeda Galaxy. With eleven eruptions now identified, including eight in the past eight years, the system exhibits a recurrence period of one year, and possibly just six months. This short inter eruption period is driven by the combination of a high mass white dwarf ($1.38\\,\\mathrm{M}_\\odot$) and high mass accretion rate ($\\sim1.6\\times10^{-7}\\,\\mathrm{M}_\\odot\\,\\mathrm{yr}^{-1}$). Such a high accretion rate appears to be provided by the stellar wind of a red giant companion. Deep H$\\alpha$ observations have revealed the presence of a vastly extended nebula around the system, which could be the `super-remnant' of many thousands of past eruptions. With a prediction of the white dwarf reaching the Chandrasekhar mass in less than a mega-year, M31N 2008-12a has become the leading pre-explosion type Ia supernova candidate. The 2016 eruption - to be the twelfth detected eruption - is expected imminently, and a vast array of follow-up observations are already...

  12. Remarkable improvement of methylglyoxal synthase thermostability by His-His interaction.

    Mohammadi, Malihe; Kashi, Mona Atabakhshi; Zareian, Shekufeh; Mirshahi, Manoochehr; Khajeh, Khosro


    Lately it has been proposed that interaction between two positively charged side chains can stabilize the folded state of proteins. To further explore this point, we studied the effect of histidine-histidine interactions on thermostability of methylglyoxal synthase from Thermus sp. GH5 (TMGS). The crystal structure of TMGS revealed that His23, Arg22, and Phe19 are in close distance and form a surface loop. Here, two modified enzymes were produced by site-directed mutagenesis (SDM); one of them, one histidine (TMGS-HH(O)), and another two histidines (TMGS-HHH(O)) were inserted between Arg22 and His23 (H(O)). In comparison with the wild type, TMGS-HH(O) thermostability increased remarkably, whereas TMGS-HHH(O) was very unstable. To explore the role of His23 in the observed phenomenon, the original His23 in TMGS-HHH(O) was replaced with Ala (TMGS-HHA). Our data showed that the half-life of TMGS-HHA decreased in relation to the wild type. However, its half-life increased in comparison with TMGS-HHH(O). These results demonstrated that histidine-histidine interactions at position 23 in TMGS-HH(O) probably have the main role in TMGS thermostability.

  13. Topological switching between an alpha-beta parallel protein and a remarkably helical molten globule.

    Nabuurs, Sanne M; Westphal, Adrie H; aan den Toorn, Marije; Lindhoud, Simon; van Mierlo, Carlo P M


    Partially folded protein species transiently exist during folding of most proteins. Often these species are molten globules, which may be on- or off-pathway to native protein. Molten globules have a substantial amount of secondary structure but lack virtually all the tertiary side-chain packing characteristic of natively folded proteins. These ensembles of interconverting conformers are prone to aggregation and potentially play a role in numerous devastating pathologies, and thus attract considerable attention. The molten globule that is observed during folding of apoflavodoxin from Azotobacter vinelandii is off-pathway, as it has to unfold before native protein can be formed. Here we report that this species can be trapped under nativelike conditions by substituting amino acid residue F44 by Y44, allowing spectroscopic characterization of its conformation. Whereas native apoflavodoxin contains a parallel beta-sheet surrounded by alpha-helices (i.e., the flavodoxin-like or alpha-beta parallel topology), it is shown that the molten globule has a totally different topology: it is helical and contains no beta-sheet. The presence of this remarkably nonnative species shows that single polypeptide sequences can code for distinct folds that swap upon changing conditions. Topological switching between unrelated protein structures is likely a general phenomenon in the protein structure universe.

  14. The remarkable environmental rebound effect of electric cars: a microeconomic approach.

    Font Vivanco, David; Freire-González, Jaume; Kemp, René; van der Voet, Ester


    This article presents a stepwise, refined, and practical analytical framework to model the microeconomic environmental rebound effect (ERE) stemming from cost differences of electric cars in terms of changes in multiple life cycle environmental indicators. The analytical framework is based on marginal consumption analysis and hybrid life cycle assessment (LCA). The article makes a novel contribution through a reinterpretation of the traditional rebound effect and methodological refinements. It also provides novel empirical results about the ERE for plug-in hybrid electric (PHE), full-battery electric (FBE), and hydrogen fuel cell (HFC) cars for Europe. The ERE is found to have a remarkable impact on product-level environmental scores. For the PHE car, the ERE causes a marginal increase in demand and environmental pressures due to a small decrease in the cost of using this technology. For FBE and HFC cars, the high capital costs cause a noteworthy decrease in environmental pressures for some indicators (negative rebound effect). The results corroborate the concern over the high influence of cost differences for environmental assessment, and they prompt sustainable consumption policies to consider markets and prices as tools rather than as an immutable background.

  15. A remarkable story! M.C. Vos (1759–1825 in the light of his times

    Benno A. Zuiddam


    Full Text Available This article established the role of the Rev. M.C. Vos (1759–1825 as an internationally oriented Pietistic minister who encouraged mission work amongst the slaves and non-Europeans in the Cape Colony. It clears up several misunderstandings about Vos’s genealogy and argues that there is no genealogical warrant to treat Vos as something else than a White, European minister and writer. His cultural setting and ancestry was that of a colonial Dutchman, although it may have been Euro-Asian to some small extent. If so, this could have predisposed him naturally to look kindly on the lot of  Bengal and Malayan slaves. The real motivating factor for Vos’s missionary endeavours was not racial, but spiritual. The promotion of the Gospel and knowledge of the Scriptures was foremost in the mind of this Dutch Reformed minister. This article argues that the Bible and divine guidance had a remarkable influence on the life and actions of M.C. Vos, to the extent that even his autobiography is marked by Biblical language. Vos is placed within the historical perspective of his times, which assists a balanced interpretation of this remarkable person and his convictions.’n Merkwaardige verhaal! Die lewe en historiese omstandighede van M.C.Vos (1759–1825. Hierdie artikel het die historiese rol van Ds. M.C. Vos (1759–1825 vasgestel as ’n internasionale Piëtistiese wat sending bedryf het onder die slawe en nie-Europeërs aan die Kaap. Dit helder misverstande op wat ontstaan het oor die genealogie van Vos en stel dat daar geen genealogiese rede is om Vos te beskou as ’n predikant en skrywer van nie-Europese afkoms nie. Sy kultuur en voorgeslag was dié van ’n Nederlandse kolonis, hoewel daar enige Euro-Asiatiese elemente in sy genealogie mag wees. Indien dit die geval is, dan het dit bygedra tot sy natuurlike simpatie vir die lot van die Bengaalse en Maleise slawe. Hierdie artikel toon egter aan dat die motivering vir die sendingarbeid van Vos nie op

  16. Design of HIV-1 Protease Inhibitors with Amino-bis-tetrahydrofuran Derivatives as P2-Ligands to Enhance Backbone-Binding Interactions. Synthesis, Biological Evaluation, and Protein-Ligand X-ray Studies

    Ghosh, Arun K.; Martyr, Cuthbert D.; Osswald, Heather L.; Sheri, Venkat Reddy; Kassekert, Luke A.; Chen, Shujing; Agniswamy, Johnson; Wang, Yuan-Fang; Hayashi, Hironori; Aoki, Manabu; Weber, Irene T.; Mitsuya, Hiroaki (GSU); (Kumamoto); (Purdue)


    Structure-based design, synthesis, and biological evaluation of a series of very potent HIV-1 protease inhibitors are described. In an effort to improve backbone ligand–binding site interactions, we have incorporated basic-amines at the C4 position of the bis-tetrahydrofuran (bis-THF) ring. We speculated that these substituents would make hydrogen bonding interactions in the flap region of HIV-1 protease. Synthesis of these inhibitors was performed diastereoselectively. A number of inhibitors displayed very potent enzyme inhibitory and antiviral activity. Inhibitors 25f, 25i, and 25j were evaluated against a number of highly-PI-resistant HIV-1 strains, and they exhibited improved antiviral activity over darunavir. Two high resolution X-ray structures of 25f- and 25g-bound HIV-1 protease revealed unique hydrogen bonding interactions with the backbone carbonyl group of Gly48 as well as with the backbone NH of Gly48 in the flap region of the enzyme active site. These ligand–binding site interactions are possibly responsible for their potent activity.

  17. Has the intensity of the interannual variability in summer rainfall over South China remarkably increased?

    Fan, Ke; Xu, Zhiqing; Tian, Baoqiang


    It is indicated in this paper that there were substantial differences of interannual variability (IIV) in summer rainfall over South China (RSC) among 1960-1977, 1978-1988, and 1989-2010. Notably, both IIV and mean RSC have significantly increased after 1992/1993. Relative to 1978-1988, the percentage increase of standard deviation (SD) of RSC is 230.32 % for 1993-2010. It indicates remarkable increase in IIV of RSC occurred 1993-2010, concurrent with rainfall increase. The results show that the mid-tropospheric meridional gradient of temperature over East Asia weakened in the later period, resulting in an anomalous cyclonic circulation, transporting more tropospheric moisture to South China and an upward motion at the middle and low levels of the troposphere. Meanwhile, IIV in the mid-tropospheric meridional gradient of temperature over East Asia resulted in IIVs both in the anomalous cyclonic circulation and in vertically integrated moisture content over South China. This scenario led to a significant increase in the IIV of summer rainfall over South China. Compared to 1978-1988, a greater increase in the IIV of warming over Mongolia-northeastern China and of excessive spring snow depth over the southeastern Tibetan Plateau were responsible for the increase in the IIV of the mid-tropospheric meridional gradient of the East Asian temperature during 1993-2010. Moreover, another slight increase in the IIV of summer rainfall over South China occurred in 1960-1977 relative to 1978-1988, which partly resulted from the weakening East Asian summer monsoon variability in the late 1970s.

  18. Remarkable evolutionary relatedness among the enzymes and proteins from the α-amylase family.

    Janeček, Štefan; Gabriško, Marek


    The α-amylase is a ubiquitous starch hydrolase catalyzing the cleavage of the α-1,4-glucosidic bonds in an endo-fashion. Various α-amylases originating from different taxonomic sources may differ from each other significantly in their exact substrate preference and product profile. Moreover, it also seems to be clear that at least two different amino acid sequences utilizing two different catalytic machineries have evolved to execute the same α-amylolytic specificity. The two have been classified in the Cabohydrate-Active enZyme database, the CAZy, in the glycoside hydrolase (GH) families GH13 and GH57. While the former and the larger α-amylase family GH13 evidently forms the clan GH-H with the families GH70 and GH77, the latter and the smaller α-amylase family GH57 has only been predicted to maybe define a future clan with the family GH119. Sequences and several tens of enzyme specificities found throughout all three kingdoms in many taxa provide an interesting material for evolutionarily oriented studies that have demonstrated remarkable observations. This review emphasizes just the three of them: (1) a close relatedness between the plant and archaeal α-amylases from the family GH13; (2) a common ancestry in the family GH13 of animal heavy chains of heteromeric amino acid transporter rBAT and 4F2 with the microbial α-glucosidases; and (3) the unique sequence features in the primary structures of amylomaltases from the genus Borrelia from the family GH77. Although the three examples cannot represent an exhaustive list of exceptional topics worth to be interested in, they may demonstrate the importance these enzymes possess in the overall scientific context.

  19. The baker's yeast diploid genome is remarkably stable in vegetative growth and meiosis.

    K T Nishant


    Full Text Available Accurate estimates of mutation rates provide critical information to analyze genome evolution and organism fitness. We used whole-genome DNA sequencing, pulse-field gel electrophoresis, and comparative genome hybridization to determine mutation rates in diploid vegetative and meiotic mutation accumulation lines of Saccharomyces cerevisiae. The vegetative lines underwent only mitotic divisions while the meiotic lines underwent a meiotic cycle every ∼20 vegetative divisions. Similar base substitution rates were estimated for both lines. Given our experimental design, these measures indicated that the meiotic mutation rate is within the range of being equal to zero to being 55-fold higher than the vegetative rate. Mutations detected in vegetative lines were all heterozygous while those in meiotic lines were homozygous. A quantitative analysis of intra-tetrad mating events in the meiotic lines showed that inter-spore mating is primarily responsible for rapidly fixing mutations to homozygosity as well as for removing mutations. We did not observe 1-2 nt insertion/deletion (in-del mutations in any of the sequenced lines and only one structural variant in a non-telomeric location was found. However, a large number of structural variations in subtelomeric sequences were seen in both vegetative and meiotic lines that did not affect viability. Our results indicate that the diploid yeast nuclear genome is remarkably stable during the vegetative and meiotic cell cycles and support the hypothesis that peripheral regions of chromosomes are more dynamic than gene-rich central sections where structural rearrangements could be deleterious. This work also provides an improved estimate for the mutational load carried by diploid organisms.

  20. Remarkable Evolutionary Conservation of Antiobesity ADIPOSE/WDTC1 Homologs in Animals and Plants.

    Ducos, Eric; Vergès, Valentin; Dugé de Bernonville, Thomas; Blanc, Nathalie; Giglioli-Guivarc'h, Nathalie; Dutilleul, Christelle


    ASG2 (Altered Seed Germination 2) is a prenylated protein in Arabidopsis thaliana that participates to abscisic acid signaling and is proposed to act as a substrate adaptor for the DDB1 (DNA damage-binding protein 1)-CUL4 (Cullin 4) E3 ubiquitin ligase complex. ASG2 harbors WD40 and TetratricoPeptide Repeat (TPR) domains, and resembles the well-conserved animal gene called ADP (antiobesity factor ADIPOSE) in fly and WDTC1 (WD40 and TPR 1) in humans. Loss of function of WDTC1 results in an increase in adipocytes, fat accumulation, and obesity. Antiadipogenic functions of WDTC1 involve regulation of fat-related gene transcription, notably through its binding to histone deacetylases (HDACs). Our sequence and phylogenetic analysis reveals that ASG2 belongs to the ADP/WDTC1 cluster. ASG2 and WDTC1 share a highly conserved organization that encompasses structural and functional motifs: seven WD40 domains and WD40 hotspot-related residues, three TPR protein-protein interaction domains, DDB1-binding elements [H-box and DWD (DDB1-binding WD40 protein)-box], and a prenylatable C-terminus. Furthermore, ASG2 involvement in fat metabolism was confirmed by reverse genetic approaches using asg2 knockout Arabidopsis plants. Under limited irradiance, asg2 mutants produce "obese" seeds characterized by increased weight, oil body density, and higher fatty acid contents. In addition, considering some ASG2- and WDTC1-peculiar properties, we show that the WDTC1 C-terminus is prenylated in vitro and HDAC-binding capability is conserved in ASG2, suggesting that the regulation mechanism and targets of ADP/WDTC1-like proteins may be conserved features. Our findings reveal the remarkable evolutionary conservation of the structure and the physiological role of ADIPOSE homologs in animals and plants. Copyright © 2017 by the Genetics Society of America.

  1. Remarkable influence of microwave heating on Morita-baylis-Hillman reaction in PEG-200

    Aravind A


    Full Text Available Abstract Background Morita Baylis Hillman (MBH reaction is used to introduce carbon-carbon or carbon-heteroatom bond in a molecule. The major drawback of this reaction is the relatively low product yield and long reaction time. Though notable changes have been made to improve the reaction rate and yield of MBH adduct by various groups, a reliable synthetic procedure under ambient temperature in presence moisture and air is remain unsolved. Continuing the effort to improve the rate and yield, we report here an eco-friendly and cost-effective method to generate MBH adducts. Non-volatile polyethylene glycol-200 is used as reusable solvents and the reaction was carried out under the influence of microwave energy. Results Microwave irradiation have a remarkable influence on PEG suspended 4-Diazabicyclo [2.2.2] octane (DABCO catalysed MBH reaction between aldehydes and ethyl acrylate. Molecular weight of the PEG is found to have a significant influence on the reaction yield. PEG-200 was the most efficient solvent and in combination with DABCO, the medium can be recycled upto three more runs. This reaction condition is successfully applied to obtain MBH adduct of five different aldehydes in very short time with excellent yield and the required catalyst concentration was very low compared to standard MBH reaction. Since the MBH adduct is an important reactive intermediates for many complex organic syntheses, this approach can be successfully utilised as an alternative to existing reaction conditions. Conclusion A new method was developed to improve the reaction rate and yield of MBH reaction The PEG 200-DABCO combination provides a sustainable, non-volatile, recyclable and environment friendly solvent medium to produce MBH adducts. This medium in combination with microwave energy proved to be very effective to introduce a new carbon-carbon or a carbon-heteroatom bond in a molecule.

  2. Methanolic Extract of Plumbago Zeylanica - A Remarkable Antibacterial Agent Against Many Human and Agricultural Pathogens

    Mukesh Kumar Singh


    Full Text Available Objectives: The current investigation was carried out to determine the cytotoxic and the antimicrobial activities of methanolic extracts of Plumbago zeylanica. Methods: The stems, leaves, and whole plants were air dried and extracted with methanol by using a Soxhlet extractor for 72 hours at 55 - 60°C. The antimicrobial activities were determined from the zones of inhibition, which were measured by using the agar well diffusion method, and the cytotoxicity assays were performed using the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay method. Results: The methanolic extracts of the stem and the leaves of Plumbago zeylanica were tested against six bacterial species and nine fungal species, and both extracts showed antimicrobial activity in a dose-dependent manner. The leaf extract of Plumbago zeylanica showed maximum antimicrobial activity against both Staphylococcus aureus sub sp aureus and Fusarium oxysporum. The stem extract was found to be more antimicrobial against the Pseudomonas aeruginosa and the Penicillium expansum species. MTT assays were used to test the cytotoxicity of the whole plant extract in the HCT-116 and the K-562 cell lines, and that extract was shown to have weak cytotoxicity in both cell lines. Conclusion: In the present study, the methanolic stem extracts of Plumbago zeylanica were found to possess remarkable antibacterial activities against many human and agricultural pathogens. The extracts were also found to possess significant antifungal activities, but the antifungal activities were less than the antibacterial activities. Finally, the extracts were found to have weak cytotoxicities in the HCT-116 and the K-562 cell lines.

  3. Development of n-type cobaltocene-encapsulated carbon nanotubes with remarkable thermoelectric property

    Fukumaru, Takahiro; Fujigaya, Tsuyohiko; Nakashima, Naotoshi


    Direct conversion from heat to electricity is one of the important technologies for a sustainable society since large quantities of energy are wasted as heat. We report the development of a single-walled carbon nanotube (SWNT)-based high conversion efficiency, air-stable and flexible thermoelectric material. We prepared cobaltocene-encapsulated SWNTs (denoted CoCp2@SWNTs) and revealed that the material showed a negative-type (n-type) semiconducting behaviour (Seebeck coefficient: -41.8 μV K-1 at 320 K). The CoCp2@SWNT film was found to show a high electrical conductivity (43,200 S m-1 at 320 K) and large power factor (75.4 μW m-1 K-2) and the performance was remarkably stable under atmospheric conditions over a wide range of temperatures. The thermoelectric figure of merit (ZT) value of the CoCp2@SWNT film (0.157 at 320 K) was highest among the reported n-type organic thermoelectric materials due to the large power factor and low thermal conductivity (0.15 W m-1 K-1). These characteristics of the n-type CoCp2@SWNTs allowed us to fabricate a p-n type thermoelectric device by combination with an empty SWNT-based p-type film. The fabricated device exhibited a highly efficient power generation close to the calculated values even without any air-protective coating due to the high stability of the SWNT-based materials under atmospheric conditions.

  4. Rare or remarkable microfungi from Oaxaca (south Mexico)--Part II.

    Ale-Agha, N; Jensen, M; Brassmann, M; Kautz, S; Eilmus, S; Ballhorn, D J


    Microfungi were collected in southern Mexico in the vicinity of Puerto Escondido, Oaxaca in 2007. In 2006, samples were gathered from Acacia myrmecophytes [(Remarkable microfungi from Oaxaca of Acacia species) Part I]. In the present investigation [Part II], we collected microfungi from different parts of a variety of wild and cultivated higher plants belonging to the families Anacardiaceae, Caricaceae, Fabaceae, Moraceae, and Nyctaginacae. The microfungi found here live as parasites or saprophytes. Interestingly, the species Colletotrichum lindemuthianum (Sacc. and Magn.) Briosi and Cavara has repeatedly been used to cause fungal infections of Phaseolus lunatus leaves in laboratory experiments. We could now find the same fungus as parasite on the same host plants under field conditions showing that results obtained in the laboratory are also relevant in nature. Most of the fungal species collected belong to the classes Ascomycotina, Basidiomycotina and Deuteromycotina. Until now, some of the microfungi identified in this study have been rarely observed before or have been reported for the first time in Mexico, for example: Pestalotia acaciae Thüm. on Acacia collinsii Safford; Corynespora cassiicola (Berk. and M.A. Curtis) C.T. Wei on Carica papaya L.; Botryosphaeria ribis Grossenb. and Duggar and Cercosporella leucaenae (Raghu Ram and Mallaiah) U. Braun (new for Mexico) and Camptomeris leucaenae (F. Stevens and Dalbey) Syd. (new for Mexico) on Leucaena leucocephala (Lam.) de Wit.; Oidium clitoriae Narayanas. and K. Ramakr. and Phakopsora cf. pachyrhizi Sydow and Sydow (new for Mexico) on Clitoria ternatea L.; Botryosphaeria obtusa (Schw.) Shoemaker on Prosopis juliflora (Sw.) DC.; Cylindrocladium scoparium Morg. on Ficus benjamina L.; Acremonium sp. on Bougainvillea sp. All specimens are located in the herbarium ESS. Mycotheca Parva collection G.B. Feige and N. Ale-Agha.

  5. Remarkable variation in maize genome structure inferred from haplotype diversity at the bz locus.

    Wang, Qinghua; Dooner, Hugo K


    Maize is probably the most diverse of all crop species. Unexpectedly large differences among haplotypes were first revealed in a comparison of the bz genomic regions of two different inbred lines, McC and B73. Retrotransposon clusters, which comprise most of the repetitive DNA in maize, varied markedly in makeup, and location relative to the genes in the region and genic sequences, later shown to be carried by two helitron transposons, also differed between the inbreds. Thus, the allelic bz regions of these Corn Belt inbreds shared only a minority of the total sequence. To investigate further the variation caused by retrotransposons, helitrons, and other insertions, we have analyzed the organization of the bz genomic region in five additional cultivars selected because of their geographic and genetic diversity: the inbreds A188, CML258, and I137TN, and the land races Coroico and NalTel. This vertical comparison has revealed the existence of several new helitrons, new retrotransposons, members of every superfamily of DNA transposons, numerous miniature elements, and novel insertions flanked at either end by TA repeats, which we call TAFTs (TA-flanked transposons). The extent of variation in the region is remarkable. In pairwise comparisons of eight bz haplotypes, the percentage of shared sequences ranges from 25% to 84%. Chimeric haplotypes were identified that combine retrotransposon clusters found in different haplotypes. We propose that recombination in the common gene space greatly amplifies the variability produced by the retrotransposition explosion in the maize ancestry, creating the heterogeneity in genome organization found in modern maize.

  6. Micro-array profiling exhibits remarkable intra-individual stability of human platelet micro-RNA.

    Stratz, C; Nührenberg, T G; Binder, H; Valina, C M; Trenk, D; Hochholzer, W; Neumann, F J; Fiebich, B L


    Platelets play an important role in haemostasis and thrombus formation. Latest research identified platelets harbouring so called microRNAs (miRNA). MiRNAs are short single-stranded RNAs modulating gene expression by targeting mRNAs. Limited data exist on inter-individual variability of platelet miRNA profile while no data are available on intra-individual variability. We assessed platelet miRNA profile in five volunteers at five time points over a time course of 10 days; 24 hours prior to the last blood sampling, subjects took 500 mg acetylsalicylic acid (ASA). Platelet miRNA was isolated from leucocyte-depleted platelet-rich plasma, and miRNA array-analysis was performed. Temporal patterns and ASA effect were explored by a linear mixed effects model for each miRNA. For the 20 most abundantly expressed platelet miRNAs, target gene search was performed and an annotation network was created. MiRNA expression profiling of 1,281 human miRNAs revealed relevant expression of 221 miRNAs consistently expressed in all samples at all time points. Correlation of platelet miRNA ranks was highly significant to other studies. Global distribution of miRNA expression was relatively similar in all subjects. No miRNA exhibited a significant effect of time at level 0.05. After 24 hours, no significant effect of ASA was found. Concerning functional implications of the 20 most abundantly expressed miRNAs, we found six functional themes. In conclusion, platelet miRNA profile is remarkably stable over the time period studied. Single-point analysis of platelet miRNA profile is reasonable when inter-individual differences are studied. The functional annotation network points toward extra-platelet effects of platelet miRNAs.

  7. Remarkably selective recognition of iodobenzene derivatives by a macrocyclic bis-Pt(II) metallohost.

    Trokowski, Robert; Akine, Shigehisa; Nabeshima, Tatsuya


    We designed and synthesized self-assembled bis-Pt(II) dimer 1⋅4 BF(4) with quino[8,7-b][1,10]phenanthroline as an extended π-face contact area, which acts as the first artificial receptor with high affinity toward iodinated aromatic compounds significantly based on noncovalent iodine⋅⋅⋅aromatic-plane interactions in a "side-on" fashion. Despite their structural similarity to a previously reported metallohost 2(4+) that bears 2,2':6',2''-terpyridine units, a dramatic change in selectivity toward substituted benzene derivatives was observed for 1(4+). (1)H NMR spectroscopic titration revealed a high affinity of 1(4+) towards haloarenes, with exceptionally large association constants for 2-iodophenol (K(a) = 16,000  M(-1)) and 1,2-diiodobenzene (K(a) = 21,000  M(-1)), which are 93- and 140-fold higher, respectively, than the values obtained for 2(4+). In addition, 1(4+) showed a remarkably high affinity and selectivity toward 2,6-diiodophenol (K(a) = 35,000  M(-1)), which is an important substructure of the thyroid hormone T(4). X-ray crystallography and theoretical calculations strongly suggest that "side-on" iodine⋅⋅⋅aromatic-plane interactions and π-π stacking contribute to the strong 1,2-diiodobenzene and 2,6-diiodophenol binding. The results obtained here give unique and valuable insight into the nature of halogen atom interactions in their "side-on" region with an electropositive aromatic plane, which may provide useful guidance for designing artificial receptors for iodinated biomolecules. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Methanolic Extract of Plumbago Zeylanica - A Remarkable Antibacterial Agent Against Many Human and Agricultural Pathogens

    Pandey, Ajit; Sawarkar, Hemant; Gupta, Anshita; Gidwani, Bina; Dhongade, Hemant; Tripathi, Dulal Krishna


    Objectives: The current investigation was carried out to determine the cytotoxic and the antimicrobial activities of methanolic extracts of Plumbago zeylanica. Methods: The stems, leaves, and whole plants were air dried and extracted with methanol by using a Soxhlet extractor for 72 hours at 55 - 60°C. The antimicrobial activities were determined from the zones of inhibition, which were measured by using the agar well diffusion method, and the cytotoxicity assays were performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay method. Results: The methanolic extracts of the stem and the leaves of Plumbago zeylanica were tested against six bacterial species and nine fungal species, and both extracts showed antimicrobial activity in a dose-dependent manner. The leaf extract of Plumbago zeylanica showed maximum antimicrobial activity against both Staphylococcus aureus sub sp aureus and Fusarium oxysporum. The stem extract was found to be more antimicrobial against the Pseudomonas aeruginosa and the Penicillium expansum species. MTT assays were used to test the cytotoxicity of the whole plant extract in the HCT-116 and the K-562 cell lines, and that extract was shown to have weak cytotoxicity in both cell lines. Conclusion: In the present study, the methanolic stem extracts of Plumbago zeylanica were found to possess remarkable antibacterial activities against many human and agricultural pathogens. The extracts were also found to possess significant antifungal activities, but the antifungal activities were less than the antibacterial activities. Finally, the extracts were found to have weak cytotoxicities in the HCT-116 and the K-562 cell lines.

  9. Controlled synthesis of titania using water-soluble titanium complexes: A review

    Truong, Quang Duc; Dien, Luong Xuan; Vo, Dai-Viet N.; Le, Thanh Son


    The development of human society has led to the increase in energy and resources consumption as well as the arising problems of environmental damage and the toxicity to the human health. The development of novel synthesis method which tolerates utilization of toxic solvents and chemicals would fulfill the demand of the society for safer, softer, and environmental friendly technologies. For the past decades, a remarkable progress has been attained in the development of new water-soluble titanium complexes (WSTC) and their use for the synthesis of nanocrystalline titanium dioxide materials by aqueous solution-based approaches. The progress of synthesis of nanocrystalline titanium dioxide using such WSTCs is reviewed in this work. The key structural features responsible for the successfully controlled synthesis of TiO2 are discussed to provide guidelines for the morphology-controlled synthesis. Finally, this review ends with a summary and some perspectives on the challenges as well as new directions in this fascinating research.

  10. A selective mitochondrial-targeted chlorambucil with remarkable cytotoxicity in breast and pancreatic cancers.

    Millard, Melissa; Gallagher, John D; Olenyuk, Bogdan Z; Neamati, Nouri


    Nitrogen mustards, widely used as chemotherapeutics, have limited safety and efficacy. Mitochondria lack a functional nucleotide excision repair mechanism to repair DNA adducts and are sensitive to alkylating agents. Importantly, cancer cells have higher intrinsic mitochondrial membrane potential (Δψmt) than normal cells. Therefore, selectively targeting nitrogen mustards to cancer cell mitochondria based on Δψmt could overcome those limitations. Herein, we describe the design, synthesis, and evaluation of Mito-Chlor, a triphenylphosphonium derivative of the nitrogen mustard chlorambucil. We show that Mito-Chlor localizes to cancer cell mitochondria where it acts on mtDNA to arrest cell cycle and induce cell death, resulting in a 80-fold enhancement of cell kill in a panel of breast and pancreatic cancer cell lines that are insensitive to the parent drug. Significantly, Mito-Chlor delayed tumor progression in a mouse xenograft model of human pancreatic cancer. This is a first example of repurposing chlorambucil, a drug not used in breast and pancreatic cancer treatment, as a novel drug candidate for these diseases.

  11. Coelomocytes: Biology and Possible Immune Functions in Invertebrates with Special Remarks on Nematodes

    Qudsia Tahseen


    Full Text Available All metazoans are exposed to a wide range of microbes and have evolved complex immune defenses used to repel infectious agents. Coelomocytes play a key role in the defense reactions of most invertebrates. They are involved in important immune functions, such as phagocytosis, encapsulation, graft rejection, and inflammation, as well as the synthesis and secretion of several humoral factors especially in annelids and echinoderms. Coelomocytes in nematodes are variable in shapes from round, ovoid, cuboidal, and spindle-shaped to stellate or branched cells that are found usually at fixed positions in the pseudocoelom. Their number usually varies from 2 to 6. The model nematode, C. elegans lacks an adaptive immune system and the coelomocytes are capable of endocytosis, but their involvement in phagocytosis of bacteria seems unlikely. The aim of this review is to evaluate current knowledge on coelomocytes of invertebrates with special reference to nematodes. The morphology and structure of these coelomocytes are discussed along with their origin. Their relative positions and diversity in different nematode groups have also been discussed and illustrated.

  12. Enantiospecific total synthesis of the important biogenetic intermediates along the ajmaline pathway, (+)-polyneuridine and (+)-polyneuridine aldehyde, as well as 16-epivellosimine and macusine A.

    Yin, Wenyuan; Kabir, M Shahjahan; Wang, Zhijian; Rallapalli, Sundari K; Ma, Jun; Cook, James M


    The first stereospecific synthesis of polyneuridine aldehyde (6), 16-epivellosimine (7), (+)-polyneuridine (8), and (+)-macusine A (9) has been accomplished from commercially available d-(+)-tryptophan methyl ester. d-(+)-Tryptophan has served here both as the chiral auxiliary and the starting material for the synthesis of the common intermediate, (+)-vellosimine (13). This alkaloid was available in enantiospecific fashion in seven reaction vessels in 27% overall yield from d-(+)-trytophan methyl ester (14) via a combination of the asymmetric Pictet-Spengler reaction, Dieckmann cyclization, and a stereocontrolled intramolecular enolate-driven palladium-mediated cross-coupling reaction. A new process for this stereocontrolled intramolecular cross-coupling has been developed via a copper-mediated process. The initial results of this investigation indicated that an enolate-driven palladium-mediated cross-coupling reaction can be accomplished by a copper-mediated process which is less expensive and much easier to work up. An enantiospecific total synthesis of (+)-polyneuridine aldehyde (6), which has been proposed as an important biogenetic intermediate in the biosynthesis of quebrachidine (2), was then accomplished in an overall yield of 14.1% in 13 reaction vessels from d-(+)-tryptophan methyl ester (14). Aldehyde 13 was protected as the N(a)-Boc aldehyde 32 and then converted into the prochiral C(16)-quaternary diol 12 via the practical Tollens' reaction and deprotection. The DDQ-mediated oxidative cyclization and TFA/Et(3)SiH reductive cleavage served as protection/deprotection steps to provide a versatile entry into the three alkaloids polyneuridine aldehyde (6), polyneuridine (8), and macusine A (9) from the quarternary diol 12. The oxidation of the 16-hydroxymethyl group present in the axial position was achieved with the Corey-Kim reagent to provide the desired beta-axial aldehydes, polyneuridine aldehyde (6), and 16-epivellosimine (7) with 100

  13. Enantiospecific Total Synthesis of the Important Biogenetic Intermediates Along the Ajmaline Pathway, (+)-Polyneuridine and (+)-Polyneuridine Aldehyde, as well as 16-Epi-Vellosimine and Macusine A

    Yin, Wenyuan; Kabir, M. Shahjahan; Wang, Zhijian; Rallapalli, Sundari K.; Ma, Jun; Cook, James M.


    The first stereospecific synthesis of polyneuridine aldehyde (6), 16-epi-vellosimine (7), (+)-polyneuridine (8), and (+)-macusine A (9) has been accomplished from commercially available D-(+)-tryptophan methyl ester. D-(+)-Tryptophan has served here both as the chiral auxiliary and the starting material for the synthesis of the common intermediate, (+)-vellosimine (13). This alkaloid was available in enantiospecific fashion in seven reaction vessels in 27% overall yield from D-(+)-trytophan methyl ester (14) via a combination of the asymmetric Pictet-Spengler reaction, Dieckmann cyclization, and a stereocontrolled intramolecular enolate-driven palladium-mediated cross-coupling reaction. A new process for this stereocontrolled intramolecular cross-coupling has been developed via a copper-mediated process. The initial results of this investigation indicated that an enolate driven palladium-mediated cross-coupling reaction can be accomplished by a copper-mediated process which is less expensive and much easier to work-up. An enantiospecific total synthesis of (+)-polyneuridine aldehyde (6), which has been proposed as an important biogenetic intermediate in the biosynthesis of quebrachidine (2), was then accomplished in an overall yield of 14.1% in 13 reaction vessels from D-(+)-tryptophan methyl ester (14). Aldehyde 13 was protected as the Na-Boc aldehyde 32 and then converted into the prochiral C (16)-quaternary diol 12 via the practical Tollens’ reaction and deprotection. The DDQ-mediated oxidative cyclization and TFA/Et3SiH reductive cleavage served as protection/deprotection steps to provide a versatile entry into the three alkaloids, polyneuridine aldehyde (6), polyneuridine (8) and macusine A (9) from the quarternary diol 12. The oxidation of the 16-hydroxymethyl group present in the axial position was achieved with the Corey-Kim reagent to provide the desired β-axial aldehydes, polyneuridine aldehyde (6) and 16-epi-vellosimine (7) with 100

  14. Annotation of Protein Domains Reveals Remarkable Conservation in the Functional Make up of Proteomes Across Superkingdoms

    Nasir, Arshan; Naeem, Aisha; Khan, Muhammad Jawad; Lopez-Nicora, Horacio D.; Caetano-Anollés, Gustavo


    The functional repertoire of a cell is largely embodied in its proteome, the collection of proteins encoded in the genome of an organism. The molecular functions of proteins are the direct consequence of their structure and structure can be inferred from sequence using hidden Markov models of structural recognition. Here we analyze the functional annotation of protein domain structures in almost a thousand sequenced genomes, exploring the functional and structural diversity of proteomes. We find there is a remarkable conservation in the distribution of domains with respect to the molecular functions they perform in the three superkingdoms of life. In general, most of the protein repertoire is spent in functions related to metabolic processes but there are significant differences in the usage of domains for regulatory and extra-cellular processes both within and between superkingdoms. Our results support the hypotheses that the proteomes of superkingdom Eukarya evolved via genome expansion mechanisms that were directed towards innovating new domain architectures for regulatory and extra/intracellular process functions needed for example to maintain the integrity of multicellular structure or to interact with environmental biotic and abiotic factors (e.g., cell signaling and adhesion, immune responses, and toxin production). Proteomes of microbial superkingdoms Archaea and Bacteria retained fewer numbers of domains and maintained simple and smaller protein repertoires. Viruses appear to play an important role in the evolution of superkingdoms. We finally identify few genomic outliers that deviate significantly from the conserved functional design. These include Nanoarchaeum equitans, proteobacterial symbionts of insects with extremely reduced genomes, Tenericutes and Guillardia theta. These organisms spend most of their domains on information functions, including translation and transcription, rather than on metabolism and harbor a domain repertoire characteristic of

  15. Annotation of Protein Domains Reveals Remarkable Conservation in the Functional Make up of Proteomes Across Superkingdoms

    Gustavo Caetano-Anollés


    Full Text Available The functional repertoire of a cell is largely embodied in its proteome, the collection of proteins encoded in the genome of an organism. The molecular functions of proteins are the direct consequence of their structure and structure can be inferred from sequence using hidden Markov models of structural recognition. Here we analyze the functional annotation of protein domain structures in almost a thousand sequenced genomes, exploring the functional and structural diversity of proteomes. We find there is a remarkable conservation in the distribution of domains with respect to the molecular functions they perform in the three superkingdoms of life. In general, most of the protein repertoire is spent in functions related to metabolic processes but there are significant differences in the usage of domains for regulatory and extra-cellular processes both within and between superkingdoms. Our results support the hypotheses that the proteomes of superkingdom Eukarya evolved via genome expansion mechanisms that were directed towards innovating new domain architectures for regulatory and extra/intracellular process functions needed for example to maintain the integrity of multicellular structure or to interact with environmental biotic and abiotic factors (e.g., cell signaling and adhesion, immune responses, and toxin production. Proteomes of microbial superkingdoms Archaea and Bacteria retained fewer numbers of domains and maintained simple and smaller protein repertoires. Viruses appear to play an important role in the evolution of superkingdoms. We finally identify few genomic outliers that deviate significantly from the conserved functional design. These include Nanoarchaeum equitans, proteobacterial symbionts of insects with extremely reduced genomes, Tenericutes and Guillardia theta. These organisms spend most of their domains on information functions, including translation and transcription, rather than on metabolism and harbor a domain

  16. The remarkable effect of oxygen on the N2 selectivity of water catalytic denitrification by hydrogen.

    Constantinou, Costas L; Costa, Costas N; Efstathiou, Angelos M


    The selective catalytic reduction of nitrates (NO3-) in pure water toward N2 formation by the use of gaseous H2 and in the presence of O2 (air) at 1 atm total pressure and 25 degrees C has been investigated over Pd-Cu supported on various mixed metal oxides, x wt % MO(x(/gamma-Al2O3 (MO(x) = CeO2, SrO, Mn2O3, Cr2O3, Y2O3, and TiO2). It is demonstrated for the firsttime that a remarkable improvement in N2 reaction selectivity (by 80 percentage units) can be achieved when oxygen is present in the reducing feed gas stream. In particular, significantly lower reaction selectivities toward NH4+ and NO2- can be obtained, whereas the rate of NO3- conversion is not significantly affected. Moreover, it was shown thatthe same effect is obtained over the Pd-Cu-supported catalysts irrespective to the chemical composition of support and the initial concentration of nitrates in water used. The Pd-Cu clusters supported on 4.8 wt%TiO2/gamma-Al2O3 resulted in a solid with the best catalytic behavior compared with the rest of supports examined, both in the presence and in the absence of oxygen in the reducing feed gas stream. DRIFTS studies performed following catalytic reduction by H2 of NO3- in water revealed that the presence of TiO2 in the Pd-Cu/TiO2-Al2O3 system enhanced the reactivity of adsorbed bidentate nitrate species toward H2. Nitrosyl species adsorbed on the alumina and titania support surfaces are considered as active intermediate species of the selective catalytic reduction of NO3- by H2 in water. Pd-Cu/TiO2-Al2O3 appears to be the most selective catalyst ever reported in the literature for the reduction of nitrates present in pure water into N2 by a reducing gas mixture of H2/air.

  17. Rings and filaments: The remarkable detached CO shell of U Antliae

    Kerschbaum, F.; Maercker, M.; Brunner, M.; Lindqvist, M.; Olofsson, H.; Mecina, M.; De Beck, E.; Groenewegen, M. A. T.; Lagadec, E.; Mohamed, S.; Paladini, C.; Ramstedt, S.; Vlemmings, W. H. T.; Wittkowski, M.


    Aims: Our goal is to characterize the intermediate age, detached shell carbon star U Antliae morphologically and physically in order to study the mass-loss evolution after a possible thermal pulse. Methods: High spatial resolution ALMA observations of unprecedented quality in thermal CO lines allow us to derive first critical spatial and temporal scales and constrain modeling efforts to estimate mass-loss rates for both the present day as well as the ejection period of the detached shell. Results: The detached shell is remarkably thin, overall spherically symmetric, and shows a barely resolved filamentary substructure possibly caused by instabilities in the interaction zone of winds with different outflow velocities. The expansion age of the detached shell is of the order of 2700 yr and its overall width indicates a high expansion-velocity and high mass-loss period of only a few hundred years at an average mass-loss rate of ≈10-5 M⊙ yr-1. The post-high-mass-loss-rate-epoch evolution of U Ant shows a significant decline to a substantially lower gas expansion velocity and a mass-loss rate amounting to 4 × 10-8 M⊙ yr-1, at present being consistent with evolutionary changes as predicted for the period between thermal pulses. This paper makes use of the following ALMA data: ADS/JAO.ALMA2015.1.00007.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.The reduced ALMA FITS data cubes are available at the CDS via anonymous ftp to ( or via movie is available at

  18. Young People in Croatia in Times of Crisis and Some Remarks About Citizenship Education

    Kornelija Mrnjaus


    Full Text Available In this paper, the authors address the youth as a research phenomenon and present the current position of young people in the Croatian society. The authors exhibit interesting results of a recent study of youth in Croatia and present the results of their research conducted among Croatian students aiming to explore the attitudes of young people and to discover how young people in Croatia develop resilience in times of crisis. They continue with remarks on citizenship education in Croatia and provide an overview of the Curriculum of civic education. Authors discuss whether we are dealing with education for democratic citizenship or rather, with the consequences of the non-existence of education for democratic citizenship in times of crisis in Croatia. Autorice u ovom radu obrađuju mlade kao istraživački fenomen i predstavljaju trenutni položaj mladih ljudi u hrvatskom društvu. Autorice donose interesantne rezultate recentnog istraživanja o mladima u Hrvatskoj te prezentiraju rezultate vlastitog kvalitativnog istraživanja provedenog među hrvatskim studentima s ciljem da ispitaju stavove mladih ljudi o krizi i otkriju kako mladi ljudi u Hrvatskoj razvijaju otpornost u vremenu krize. Nastavljaju s opažanjima o građanskom odgoju u Hrvatskoj i pružaju pregled Kurikuluma građanskog odgoja. Autorice otvaraju pitanje da li se govori o građanskom odgoju ili radije o posljedicama ne postojanja građanskog odgoja u vremenu krize u Hrvatskoj. In dieser Arbeit diskutieren die Autorinnen Jugend als Forschungsphänomen und präsentieren die aktuelle Position der jungen Menschen in der kroatischen Gesellschaft. Die Autorinnen bringen interessante Ergebnisse einer aktuellen Studie der Jugend in Kroatien und präsentieren die Ergebnisse ihrer eigenen qualitativen Studie, welche sie unter kroatischen Studenten durchgeführt haben, mit dem Ziel, die Einstellungen der Jugendlichen zu untersuchen und zu entdecken, wie junge Menschen in Kroatien die

  19. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases; Part 1: alkyl halide alkylations.

    Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim A


    Alkylations of chiral or achiral Ni(II) complexes of glycine Schiff bases constitute a landmark in the development of practical methodology for asymmetric synthesis of α-amino acids. Straightforward, easy preparation as well as high reactivity of these Ni(II) complexes render them ready available and inexpensive glycine equivalents for preparing a wide variety of α-amino acids, in particular on a relatively large scale. In the case of Ni(II) complexes containing benzylproline moiety as a chiral auxiliary, their alkylation proceeds with high thermodynamically controlled diastereoselectivity. Similar type of Ni(II) complexes derived from alanine can also be used for alkylation providing convenient access to quaternary, α,α-disubstituted α-amino acids. Achiral type of Ni(II) complexes can be prepared from picolinic acid or via recently developed modular approach using simple secondary or primary amines. These Ni(II) complexes can be easily mono/bis-alkylated under homogeneous or phase-transfer catalysis conditions. Origin of diastereo-/enantioselectivity in the alkylations reactions, aspects of practicality, generality and limitations of this methodology is critically discussed.

  20. The Remarkable Synchrotron Nebula Associated with PSR J1015-5719

    Ng, Chi Yung; Bandiera, Rino; Hunstead, Richard; Johnston, Simon


    We report the discovery of a synchrotron nebula G283.1-0.59 associated with the young and energetic pulsar J1015-5719. Radio observations using the Molonglo Observatory Synthesis Telescope (MOST) and the Australia Telescope Compact Array (ATCA) at 36, 16, 6, and 3 cm reveal a complex morphology for the source. The pulsar is embedded in the "head" of the nebula with fan-shaped diffuse emission. This is connected to a circular bubble structure of 20" radius and followed by a collimated tail extending over 1'. Polarization measurements show a highly ordered magnetic field in the nebula. The intrinsic B-field wraps around the edge of the head and shows an azimuthal configuration near the pulsar, then switches direction quasi-periodically near the bubble and in the tail. Together with the flat radio spectrum observed, we suggest that this system is most plausibly a pulsar wind nebula (PWN), with the head as a bow shock that has a low Mach number and the bubble as a shell expanding in a dense environment, possibly due to flow instabilities. In addition, the bubble could act as a magnetic bottle trapping the relativistic particles. A comparison with other bow-shock PWNe with higher Mach numbers shows similar structure and B-field geometry, implying that pulsar velocity may not be the most critical factor in determining the properties of these systems.ATCA is part of the Australia Telescope National Facility which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. MOST is operated by The University of Sydney with support from the Australian Research Council and the Science Foundation for Physics within the University of Sydney. This work is supported by an ECS grant under HKU 709713P.

  1. Jurisdiction without conflict? Remarks on non-adverse proceedings in Italy

    Elisabetta Silvestri


    Full Text Available The subject. This essay describes the procedural treatment of non-contentious matters inItaly. After a brief historical recount on the evolution of the concept of ‘non-contentiousjurisdiction’, from Roman law to the law in force, the chapter emphasizes the extreme varietyof non-adverse proceedings governed by the Code of civil procedure and special statutesas well.The purpose of the article is to understand the ‘default rules’ of non-adverse proceedings(meaning the rules applicable insofar as the law does not ordain otherwise provided by theCode of civil procedure. These rules outline a procedure in chambers that is simpler andless time-consuming than the ordinary one: for these reasons, the procedure in chambershas been increasingly adopted for the judicial treatment of a few contentious matters, withmixed results.Methodology. The methodological basis for the study: general scientific methods (analysis,synthesis, comparison, description; private and academic (comparative legal, interpretation,formal-legal.Results. It is difficult to foresee whether in the near future more attention will be devotedby Italian legislators to non-contentious jurisdiction so as to lay down rules that are uniformand consistent. In recent decades, Italian civil procedure has been re-written again andagain in the attempt to solve the most serious and enduring problem of the justice system,namely, the excessive length of proceedings.Conclusions. As far as non-contentious matters, in light of the notorious overload of Italiancourts the author believes that they could be handles more efficiently by administrativeauthorities.

  2. In tandem or alone: a remarkably selective transfer hydrogenation of alkenes catalyzed by ruthenium olefin metathesis catalysts.

    Zieliński, Grzegorz Krzysztof; Samojłowicz, Cezary; Wdowik, Tomasz; Grela, Karol


    A system for transfer hydrogenation of alkenes, composed of a ruthenium metathesis catalyst and HCOOH, is presented. This operationally simple system can be formed directly after a metathesis reaction to effect hydrogenation of the metathesis product in a single-pot. These hydrogenation conditions are applicable to a wide range of alkenes and offer remarkable selectivity.

  3. Organic Cations Might Not Be Essential to the Remarkable Properties of Band Edge Carriers in Lead Halide Perovskites.

    Zhu, Haiming; Trinh, M Tuan; Wang, Jue; Fu, Yongping; Joshi, Prakriti P; Miyata, Kiyoshi; Jin, Song; Zhu, X-Y


    A charge carrier in a lead halide perovskite lattice is protected as a large polaron responsible for the remarkable photophysical properties, irrespective of the cation type. All-inorganic-based APbX3 perovskites may mitigate the stability problem for their applications in solar cells and other optoelectronics.

  4. The Combined C—H Functionalization/Cope Rearrangement: Discovery and Applications in Organic Synthesis

    Davies, Huw M. L.; Lian, Yajing


    Conspectus The development of methods for the stereoselective functionalization of sp3 C–H bonds is a challenging undertaking. This Account describes the scope of the combined C–H functionalization/Cope rearrangement (CHCR), a reaction that occurs between rhodium-stabilized vinylcarbenoids and substrates containing allylic C–H bonds. Computational studies have shown that the CHCR reaction is initiated by a hydride transfer to the carbenoid from an allyl site of the substrate, which is then rapidly followed by C–C bond formation between the developing rhodium-bound allyl anion and the allyl cation. In principle, the reaction can proceed through four distinct orientations of the vinylcarbenoid and the approaching substrate. The early examples of the CHCR reaction were all highly diastereoselective, consistent with a reaction proceeding via a chair transition state with the vinylcarbenoid adopting an s-cis conformation. Recent computational studies have revealed that other transition state orientations are energetically accessible, and these results have guided the development of highly stereoselective CHCR reactions that proceed through a boat transition state with the vinylcarbenoid in an s-cis configuration. The CHCR reaction has broad applications in organic synthesis. In some new protocols, the CHCR reaction acts as a surrogate to some of the classic synthetic strategies in organic chemistry. The CHCR reaction has served as a synthetic equivalent of the Michael reaction, the vinylogous Mukaiyama aldol reaction, the tandem Claisen rearrangement/Cope rearrangement, and the tandem aldol reaction/siloxy-Cope rearrangement. In all of these cases, the products are generated with very high diastereocontrol. With a chiral dirhodium tetracarboxylate catalyst such as Rh2(S-DOSP)4 or Rh2(S-PTAD)4, researchers can achieve very high levels of asymmetric induction. Applications of the CHCR reaction include the effective enantiodifferentiation of racemic

  5. Total Synthesis of (+)-Batzelladine A and (−)-Batzelladine D via [4 + 2]-Annulation of Vinyl Carbodiimides with N-Alkyl Imines

    Arnold, Michael A.; Day, Kenneth A.; Durón, Sergio G.; Gin, David Y.


    A diastereoselective [4 + 2]-annulation of vinyl carbodiimides with chiral N-alkyl imines has been developed to access the stereochemically rich polycyclic guanidine cores of the batzelladine alkaloids. Application of this strategy, together with additional key steps such as long-range directed hydrogenation and diastereoselective intramolecular iodo-amination, led to highly convergent total syntheses of (−)-batzelladine D and (+)-batzelladine A with excellent stereocontrol. PMID:17017806

  6. Inherently chiral calix[4]arenes via oxazoline directed ortholithiation: synthesis and probe of chiral space

    Simon A. Herbert


    Full Text Available The diastereoselective oxazoline-directed lithiation of calix[4]arenes is reported with diastereoselective ratios of greater than 100:1 in some instances. Notably, it has been found that the opposite diastereomer can be accessed via this approach merely through the choice of an alkyllithium reagent. The inherently chiral oxazoline calix[4]arenes have also been preliminarily examined as ligands in the palladium-catalyzed Tsuji–Trost allylation reaction, returning results comparable to their planar chiral ferrocene counterparts pointing towards future application of these types of compounds.

  7. Solvent-controlled synthesis of tetranuclear cage-like copper(II) silsesquioxanes. Remarkable features of the cage structures and their high catalytic activity in oxidation with peroxides.

    Dronova, Marina S; Bilyachenko, Alexey N; Yalymov, Alexey I; Kozlov, Yuriy N; Shul'pina, Lidia S; Korlyukov, Alexander A; Arkhipov, Dmitry E; Levitsky, Mikhail M; Shubina, Elena S; Shul'pin, Georgiy B


    Two principally different in their molecular architecture isomeric tetranuclear copper(ii) silsesquioxanes, "Globule"-like compound [(PhSiO1.5)12(CuO)4(NaO0.5)4] (1) and "Sandwich"-like derivative [(PhSiO1.5)6(CuO)4(NaO0.5)4(PhSiO1.5)6] (2), were synthesized by the partial cleavage of polymeric copper(ii) silsesquioxane [(PhSiO1.5)2(CuO)]n by tetraphenylcyclotetrasiloxanolate. The route leading to the formation of either 1 or 2 entirely depends on the nature and composition of the solvent used for this reaction. Thus, the process in an ethanol-1-butanol solution gives compound 1. When a 1,4-dioxane-methanol mixture was used, compound 2 was prepared. The structures and unusual crystal packing of the cages were confirmed by the X-ray studies. It has been found that the reaction of benzene with H2O2 in acetonitrile solution at 50 °C catalyzed by 1 requires addition of trifluoroacetic acid (TFA) in low concentration and gives phenol with a turnover number (TON) of 250 after 3 h. The initial reaction rate W0 linearly depends on the concentration of catalyst 2. The oxidation of 1-phenylethanol to acetophenone with hydrogen peroxide catalyzed by complex 1 in the presence of TFA is not efficient. In contrast, 1 exhibited excellent activity in the oxidation with tert-butyl hydroperoxide (TBHP) in the absence of any acid (the yield of acetophenone was close to the quantitative, TON attained 475 after 2 h). A kinetic study of this reaction led to the conclusion that the process occurs with the participation of radicals tert-BuO˙ produced in the Cu-promoted decomposition of TBHP. The mode of dependence of W0 on the initial concentration of TBHP indicates the formation of an intermediate adduct between the catalyst 1 and TBHP (characterized by the equilibrium constant K1≈ 2 M(-1) for the conditions of conducted experiments) followed by subsequent decomposition of the adduct (k2≈ 0.2 s(-1)) to generate an intermediate species tert-BuO˙ which induces the alcohol oxidation.

  8. Hierarchical architectures TiO2: pollen-inducted synthesis, remarkable crystalline-phase stability, tunable size, and reused photo-catalysis.

    Dou, Lingling; Gao, Lishuang; Yang, Xiaohui; Song, Xiuqin


    TiO(2) with hierarchical architectures, tunable crystalline phase and thermal stability is successfully fabricated on a large scale through a facile hydrolysis process of TiCl(4) combining with inducing of pollen. The structure of the as-prepared TiO(2) is characterized by X-ray diffraction, Raman spectroscopy, infrared spectra, and scanning electron microscopy. The experimental results indicate that different phases (anatase, rutile or mixed crystallite) of TiO(2) can be synthesized by controlling the experimental conditions. The pure phase of rutile or anatase can be obtained at 100°C, while the pure phase of anatase can be retained after being annealed at 900°C. The hierarchical structures TiO(2) are constitute through self-assembly of nanoparticles or nanorods TiO(2), which exhibit high and reused photo-catalytic properties for degradation of methylene blue.

  9. Remarkably efficient synthesis of 2H-indazole 1-oxides and 2H-indazoles via tandem carbon-carbon followed by nitrogen-nitrogen bond formation.

    Bouillon, Isabelle; Zajícek, Jaroslav; Pudelová, Nadĕzda; Krchnák, Viktor


    Base-catalyzed tandem carbon-carbon followed by nitrogen-nitrogen bond formations quantitatively converted N-alkyl-2-nitro-N-(2-oxo-2-aryl-ethyl)-benzenesulfonamides to 2H-indazoles 1-oxides under mild conditions. Triphenylphosphine or mesyl chloride/triethylamine-mediated deoxygenation afforded 2H-indazoles.

  10. Synthesis and Enantiomeric Separation of a Novel Spiroketal Derivative: A Potent Human Telomerase Inhibitor with High in Vitro Anticancer Activity

    Fuggetta, Maria Pia; De Mico, Antonella; Cottarelli, Andrea; Morelli, Franco; Zonfrillo, Manuela; Ulgheri, Fausta; Peluso, Paola; Mannu, Alberto; Deligia, Francesco; Marchetti, Mauro; Roviello, Giovanni; Reyes Romero, Atilio; Dömling, Alexander; Spanu, Pietro


    The synthesis, the enantiomeric separation, and the characterization of new simple spiroketal derivatives have been performed. The synthesized compounds have shown a very high anticancer activity. Cell proliferation assay showed that they induce a remarkable inhibition of cell proliferation in all

  11. Rhodium-catalyzed [5 + 2 + 1] cycloaddition of ene-vinylcyclopropanes and CO: reaction design, development, application in natural product synthesis, and inspiration for developing new reactions for synthesis of eight-membered carbocycles.

    Wang, Yi; Yu, Zhi-Xiang


    Practical syntheses of natural products and their analogues with eight-membered carbocyclic skeletons are important for medicinal and biological investigations. However, methods and strategies to construct the eight-membered carbocycles are limited. Therefore, developing new methods to synthesize the eight-membered carbocycles is highly desired. In this Account, we describe our development of three rhodium-catalyzed cycloadditions for the construction of the eight-membered carbocycles, which have great potential in addressing the challenges in the synthesis of medium-sized ring systems. The first reaction described in this Account is our computationally designed rhodium-catalyzed two-component [5 + 2 + 1] cycloaddition of ene-vinylcyclopropanes (ene-VCPs) and CO for the diastereoselective construction of bi- and tricyclic cyclooctenones. The design of this reaction is based on the hypothesis that the C(sp(3))-C(sp(3)) reductive elimination of the eight-membered rhodacycle intermediate generated from the rhodium-catalyzed cyclopropane cleavage and alkene insertion, giving Wender's [5 + 2] cycloadduct, is not easy. Under CO atmosphere, CO insertion may occur rapidly, converting the eight-membered rhodacycle into a nine-membered rhodacycle, which then undergoes an easy C(sp(2))-C(sp(3)) reductive elimination process and furnishes the [5 + 2 + 1] product. This hypothesis was supported by our preliminary DFT studies and also served as inspiration for the development of two [7 + 1] cycloadditions: the [7 + 1] cycloaddition of buta-1,3-dienylcyclopropanes (BDCPs) and CO for the construction of cyclooctadienones, and the benzo/[7 + 1] cycloaddition of cyclopropyl-benzocyclobutenes (CP-BCBs) and CO to synthesize the benzocyclooctenones. The efficiency of these rhodium-catalyzed cycloadditions can be revealed by the application in natural product synthesis. Two eight-membered ring-containing natural products, (±)-asterisca-3(15),6-diene and (+)-asteriscanolide, have been

  12. Closing Remarks of the Workshop OnGlobal University System & E-Learning

    Ali YAIZCI


    Full Text Available The Workshop on Global University System & E-Learning was held on the 19th of October, 2006 at TOBB Economics & Technology University. The workshop attracted around 40 people from the Ministry of Education, Turkish Satellite Corporation (TURKSAT, Anadolu University, and various academic staff from different universities in Ankara. All together, there were 8 presentations each followed by a discussion. Main contributors, their brief CV’s, and the workshop program are included in the preceding part of this document.Here, I would try to put together various important points and remarks made by the speakers according to the order in the program.The first talk was presented by Professor Tapio Varis, Acting President of GUS, about the Global University System (GUS. He started his talk by reviewing the trends of the 21st Century in terms of education and technology. He emphasized the need to humanize the globalization process by adding “solidarity”, “sprit of caring for”, and “sharing with others”. It was stated that, content development, especially for educational purposes, is a difficult issue in achieving this process. Professor Varis, declared “digital literacy” as being a right for all. He mentioned “phonetic alphabet” as a tool to alleviate the problems associated with the communication among different nationalities. He mentioned the need to exchange ideas, opinions and experience to create a successful working environment and stressed the importance of cultural issues such as quality assurance, translation and assessment. He also talked about open courseware, “education for all”, offered by MIT and UNESCO. Finally, Professor Varis summarized the mission of GUS as to offer a global quality education (described as a renaissance education program for developing countries and/or regions by taking into account cultural sensitivities.The second talk was presented by Professor Takeshi Utsumi about the Global Collaborative

  13. A struggle in the peripheries: a few remarks on devolution in the UK

    Łukasz Sorokowski


    Full Text Available A struggle in the peripheries: a few remarks on devolution in the UK The paper looks at the major issues underlying devolution in the United Kingdom, i.e. a process whereby the historically diverse areas and regions constituting the seemingly uniform state have been slowly striving for independence, along with the formation of local, regional and even national identities. Hinging on the idea of ‘multicultural citizenship’, the paper seeks to analyse the ongoing public discourse centered on the gradual transfer of centralized London-based power to local and regional bodies across the UK. This discourse forms the pivotal background of devolution, overtly pointing to the idea of the so-called ‘new opening’ of the entire British political scene, clearly promoting the notion of strengthening the position of Scotland, Wales, Northern Ireland, and English regions as increasingly autonomous geographical and cultural areas as part of a weakening monolith by the name of the United Kingdom. Resting almost entirely on historic tensions between British identity and Scottish identity, it is made clear that the Scottish public debate has basically neglected the issues of the assimilation of its cultural minorities with the ‘post-devolution’ reality. The devolution discourse stems from the rancorous debates and polemics which have taken place throughout the three hundred years of the Scottish and English Union, covering several social and political contexts, including the growing demands voiced by the SNP. Indeed, it has a major impact on the formation of Scots’ national distinctiveness alongside Scotland’s gradual emergence as a separate part of the British Isles.   Walka na peryferiach: kilka uwag na temat procesu dewolucji w Wielkiej Brytanii Artykuł omawia główne zagadnienia leżące u podstaw procesu dewolucyjnego w Zjednoczonym Królestwie, tj. stopniowego uniezależniania się historycznych krain – regionów współtworzących to

  14. Remarkable cycle-activated capacity increasing in onion-like carbon nanospheres as lithium battery anode material

    Dong, Jiajun; Zhang, Tong; Zhang, Dong; Zhang, Weiwei; Zhang, Huafang; Liu, Ran; Yao, Mingguang; Liu, Bingbing


    Onion-like carbon nanospheres (OCNSs) with an average diameter of 43 nm were produced on a large scale via a combustion method and examined as an anode material for lithium ion batteries. The OCNSs exhibit a remarkable electrochemical cycling behavior and a capacity much higher than that of graphite. The capacity increases significantly with increasing charge-discharge cycles and reaches a value of 178% of the initial value (from 586 mA h g-1to 1045 mA h g-1) after 200 cycles. Further investigation provides unambiguous experimental evidence that such a remarkable capacity increase is related to the stable onion-like structure of the OCNSs and to the existence of large numbers of disordered/short graphitic fragments, which gradually provide more active sites for Li ion storage. The unique electrochemical performance of OCNSs provides a new way to design a high-performance anode material for rechargeable batteries.

  15. Paecilaema batman, a new species of Brazilian troglophilous harvestman that exhibits a remarkable color patches variation (Opiliones: Cosmetidae

    Ricardo Pinto-da-Rocha


    Full Text Available A new species of harvestman, Paecilaema batman, from Brazilian limestone caves of the state of Goiás, is described, and a remarkable intraspecific color patch variation is discussed. Paecilaema batman sp. nov. differs from other species of the genus by the following combination of features: chelicera similar in both sexes; prosoma without color patches; typical color patches on area I; and area III with two high spines. The new species is considered troglophilous.

  16. Graphene Synthesis and Characterization


    AFRL-OSR-VA-TR-2015-0086 Graphene Synthesis and Characterization 130060 Andrea Cortes UNIVERSIDAD TECNICA FEDERICO SANTA MARIA Final Report 04/08...AND SUBTITLE Grant: Graphene synthesis and characterizatión 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-13-1-0060 5c. PROGRAM ELEMENT NUMBER 6...13. SUPPLEMENTARY NOTES 14. ABSTRACT Here is reported graphene synthesis by two methods, Chemical Vapor Deposition (CVD) using Acetylene as a


    Macaev Fliur


    Full Text Available Room temperature ionic liquids (ILs have been recognized as a new generation of solvents for “green chemistry” and represent remarkably promising classes of technologically useful and fundamentally interesting materials [1-6]. Most of them are quaternary imidazolium cations with inorganic counterions. Cation in these salts is appended to the organic group (usually saturated hydrocarbon fragments. However, some problems regarding the functionalization [2,7], coordination properties [4] of ILs still remain to be solved. It seems to us that functionalization of imidazoles by ethylcarbonitrile, allyl, 2,3-epoxypropyl fragments will lead to new properties of synthesized ILs. There are no literature data on use of 2-(1H-1-imidazolylethylcarbonitrile 4 for synthesis of imidazolium salts with ILs properties.

  18. Total synthesis of the Daphniphyllum alkaloid daphenylline

    Lu, Zhaoyong; Li, Yong; Deng, Jun; Li, Ang


    The Daphniphyllum alkaloids are a large class of natural products isolated from a genus of evergreen plants widely used in Chinese herbal medicine. They display a remarkable range of biological activities, including anticancer, antioxidant, and vasorelaxation properties as well as elevation of nerve growth factor. Daphenylline is a structurally unique member among the predominately aliphatic Daphniphyllum alkaloids, and contains a tetrasubstituted arene moiety mounted on a sterically compact hexacyclic scaffold. Herein, we describe the first total synthesis of daphenylline. A gold-catalysed 6-exo-dig cyclization reaction and a subsequent intramolecular Michael addition reaction, inspired by Dixon's seminal work, were exploited to construct the bridged 6,6,5-tricyclic motif of the natural product at an early stage, and the aromatic moiety was forged through a photoinduced olefin isomerization/6π-electrocyclization cascade followed by an oxidative aromatization process.

  19. Synthesis of Mechanisms

    Hansen, John Michael


    These notes describe an automated procedure for analysis and synthesis of mechanisms. The analysis method is based on the body coordinate formulation, and the synthesis is based on applying optimization methods, used to minimize the difference between an actual and a desired behaviour......These notes describe an automated procedure for analysis and synthesis of mechanisms. The analysis method is based on the body coordinate formulation, and the synthesis is based on applying optimization methods, used to minimize the difference between an actual and a desired behaviour...

  20. Synthesis of oligonucleotide phosphorodithioates

    Beaton, G.; Brill, W. K D; Grandas, A.;


    The synthesis of DNA containing sulfur at the two nonbonding internucleotide valencies is reported. Several different routes using either tervalent or pentavalent mononucleotide synthons are described. © 1991....

  1. Synthesis at the interface of chemistry and biology.

    Wu, Xu; Schultz, Peter G


    As the focus of synthesis increasingly shifts from its historical emphasis on molecular structure to function, improved strategies are clearly required for the generation of molecules with defined physical, chemical, and biological properties. In contrast, living organisms are remarkably adept at producing molecules and molecular assemblies with an impressive array of functions - from enzymes and antibodies to the photosynthetic center. Thus, the marriage of Nature's synthetic strategies, molecules, and biosynthetic machinery with more traditional synthetic approaches might enable the generation of molecules with properties difficult to achieve by chemical strategies alone. Here we illustrate the potential of this approach and overview some opportunities and challenges in the coming years.

  2. Total synthesis and allelopathic activity of cytosporones A-C

    Zamberlam, Charles E.M.; Meza, Alisson; Lima, Denis P. de; Beatriz, Adilson [Centro de Ciencias Exatas e Tecnologia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil); Leite, Carla Braga; Marques, Maria Rita [Centro de Ciencias Biologicas e da Saude, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil)


    The search for efficient, environmentally friendly herbicides has been the focus of numerous studies on the organic synthesis of compounds isolated from natural sources. Cytosporones, which are phenolic lipids isolated from fungi, exhibit noteworthy biological properties. This paper reports the preparation of cytosporones A-C from the same starting material through a short synthetic route, with good yields. All compounds were tested for allelopathic activity on lettuce (Lactuca sativa L) seeds. Cytosporone A and its methylated precursor showed remarkable allelopathic activity, inhibiting seed germination and plantule growth. (author)

  3. Carbon dots: large-scale synthesis, sensing and bioimaging

    Jia Zhang


    Full Text Available Emerging as a potent alternative to classical metal-based semiconductor quantum dots (Qdots, carbon dots (Cdots possess the distinctive advantages of convenient synthesis, prominent biocompatibility, colorful photoluminescence, and low cost. After almost a decade of extensive studies since their discovery, Cdots have widely been applied in bioimaging, sensing, catalysis, optoelectronics, energy conversion, etc. In this review, we first highlight the synthetic methods for Cdots in a macroscale manner. Second, we briefly discuss the fundamental mechanisms underlying the photoluminescence (PL. Third, we focus on their applications in sensing and bioimaging (including imaging-guided therapy. Some thoughts on future developments of Cdots are demonstrated as concluding remarks.

  4. Proline sulphonamide-catalysed Yamada-Otani condensation: reaction development, substrate scope and scaffold reactivity.

    Yang, Hua; Banerjee, Somdev; Carter, Rich G


    The development of a proline sulphonamide-catalysed method for enantioselective and diastereoselective construction of functionalized cyclohexenones is described. Impact of catalyst structure as well as solvent effects and additives are explored. A significant substrate scope is demonstrated by variation of both the aldehyde and the enone components. Diastereoselective derivatization of the cyclohexenone scaffold illustrates its utility as a building block for chemical synthesis.

  5. Synthesis of Psychrophilin E.

    Ngen, Sarah T Y; Kaur, Harveen; Hume, Paul A; Furkert, Daniel P; Brimble, Margaret A


    The first total synthesis of psychrophilin E, a potent antiproliferative cyclic tripeptide isolated from Aspergillus versicolor ZLN-60, is reported herein. Key features of the synthesis include the installation of an amide bond between the indole-nitrogen of tryptophan and an anthranilic acid residue, and a high yielding macrolactamization of the linear tripeptide to the desired macrocycle.

  6. Programing Structural Synthesis System

    Rogers, James L., Jr.


    Program aids research in analysis and optimization. Programing Structural Synthesis System (PROSSS2) developed to provide structural-synthesis capability by combining access to SPAR with CONMIN program and set of interface procedures. SPAR is large general-purpose finite-element structural-analysis program, and CONMIN is large general-purpose optimization program. PROSSS2 written in FORTRAN IV for batch execution.

  7. Hamiltonian Algorithm Sound Synthesis

    大矢, 健一


    Hamiltonian Algorithm (HA) is an algorithm for searching solutions is optimization problems. This paper introduces a sound synthesis technique using Hamiltonian Algorithm and shows a simple example. "Hamiltonian Algorithm Sound Synthesis" uses phase transition effect in HA. Because of this transition effect, totally new waveforms are produced.

  8. Formal synthesis of (+)-discodermolide.

    Francavilla, Charles; Chen, Weichun; Kinder, Frederick R


    [structure: see text] Herein we report the formal total synthesis of (+)-discodermolide in 21 steps (longest linear sequence) from commercially available Roche ester. This synthesis features the assembly of C(9-18) and C(19-24) fragments via a metal-chelated aldol coupling reaction.

  9. Synthesis of oligonucleotide phosphorodithioates

    Beaton, G.; Brill, W. K D; Grandas, A.


    The synthesis of DNA containing sulfur at the two nonbonding internucleotide valencies is reported. Several different routes using either tervalent or pentavalent mononucleotide synthons are described.......The synthesis of DNA containing sulfur at the two nonbonding internucleotide valencies is reported. Several different routes using either tervalent or pentavalent mononucleotide synthons are described....

  10. Atomically thin Pt shells on Au nanoparticle cores: facile synthesis and efficient synergetic catalysis

    Engelbrekt, Christian; Seselj, Nedjeljko; Poreddy, Raju


    We present a facile synthesis protocol for atomically thin platinum (Pt) shells on top of gold (Au) nanoparticles (NPs) (Au@PtNPs) in one pot under mild conditions. The Au@PtNPs exhibited remarkable stability (> 2 years) at room temperature. The synthesis, bimetallic nanostructures and catalytic...... clearly show that the active surface is dominated by Pt with a specific surface area above 45 m2 per gram of Pt. Interactions with the Au core increase the activity of the Pt shell by up to 55% and improve catalytic selectivity compared to pure Pt. The Au@Pt NPs show exciting catalytic activity...

  11. Nitrogen-Doped Porous Carbons from Ionic Liquids@MOF: Remarkable Adsorbents for Both Aqueous and Nonaqueous Media.

    Ahmed, Imteaz; Panja, Tandra; Khan, Nazmul Abedin; Sarker, Mithun; Yu, Jong-Sung; Jhung, Sung Hwa


    Porous carbons were prepared from a metal-organic framework (MOF, named ZIF-8), with or without modification, via high-temperature pyrolysis. Porous carbons with high nitrogen content were obtained from the calcination of MOF after introducing an ionic liquid (IL) (IL@MOF) via the ship-in-bottle method. The MOF-derived carbons (MDCs) and IL@MOF-derived carbons (IMDCs) were characterized using various techniques and used for liquid-phase adsorptions in both water and hydrocarbon to understand the possible applications in purification of water and fuel, respectively. Adsorptive performances for the removal of organic contaminants, atrazine (ATZ), diuron, and diclofenac, were remarkably enhanced with the modification/conversion of MOFs to MDC and IMDC. For example, in the case of ATZ adsorption, the maximum adsorption capacity of IMDC (Q0 = 208 m(2)/g) was much higher than that of activated carbon (AC, Q0 = 60 m(2)/g) and MDC (Q0 = 168 m(2)/g) and was found to be the highest among the reported results so far. The results of adsorptive denitrogenation and desulfurization of fuel were similar to that of water purification. The IMDCs are very useful in the adsorptions since these new carbons showed remarkable performances in both the aqueous and nonaqueous phases. These results are very meaningful because hydrophobic and hydrophilic adsorbents are usually required for the adsorptions in the water and fuel phases, respectively. Moreover, a plausible mechanism, H-bonding, was also suggested to explain the remarkable performance of the IMDCs in the adsorptions. Therefore, the IMDCs derived from IL@MOF might have various applications, especially in adsorptions, based on high porosity, mesoporosity, doped nitrogen, and functional groups.

  12. Synthesis of (1R,2S)-1-amino-2-vinylcyclopropanecarboxylic acid vinyl-ACCA) derivatives: key intermediates for the preparation of inhibitors of the hepatitis C virus NS3 protease.

    Beaulieu, Pierre L; Gillard, James; Bailey, Murray D; Boucher, Colette; Duceppe, Jean-Simon; Simoneau, Bruno; Wang, Xiao-Jun; Zhang, Li; Grozinger, Karl; Houpis, Ioannis; Farina, Vittorio; Heimroth, Heidi; Krueger, Thomas; Schnaubelt, Jürgen


    (1R,2S)-1-Amino-2-vinylcyclopropanecarboxylic acid (vinyl-ACCA) is a key building block in the synthesis of potent inhibitors of the hepatitis C virus NS3 protease such as BILN 2061, which was recently shown to dramatically reduce viral load after administration to patients infected with HCV genotype 1. We have developed a scalable process that delivers derivatives of this unusual amino acid in >99% ee. The strategy was based on the dialkylation of a glycine Schiff base using trans-1,4-dibromo-2-butene as an electrophile to produce racemic vinyl-ACCA, which was subsequently resolved using a readily available, inexpensive esterase enzyme (Alcalase 2.4L). Factors that affect diastereoselection in the initial dialkylation steps were examined and the conditions optimized to deliver the desired diastereomer selectively. Product inhibition, which was encountered during the enzymatic resolution step, initially resulted in prolonged cycle times. Enrichment of racemic vinyl-ACCA through a chemical resolution via diastereomeric salt formation or the use of forcing conditions in the enzymatic reaction both led to improvements in throughput and the development of a viable process. The chemistry described herein was scaled up to produce multikilogram quantities of this building block.

  13. A remarkable hematological and molecular response pattern in a patient with polycythemia vera during combination therapy with simvastatin and alendronate

    Anders Lindholm Sørensen


    Full Text Available We report a 57-year old man with polycythemia vera, who had a remarkable hematological and molecular response during treatment with simvastatin and alendronate. The patient was treated with this combination for 56 months, and during this period the patient has been in complete hematological remission. The JAK2-V617F allele burden has dropped from 64% to sustained values below 20%, and follow-up bone marrow biopsies have revealed no change in PV features, without any regular cytoreductive treatment.

  14. New porcine test-model reveals remarkable differences between algorithms for spectrophotometrical haemoglobin saturation measurements with VLS

    Gade, John; Greisen, Gorm


    The study created an 'ex vivo' model to test different algorithms for measurements of mucosal haemoglobin saturation with visible light spectrophotometry (VLS). The model allowed comparison between algorithms, but it also allowed comparison with co-oximetry using a 'gold standard' method. This has......  -32.8 to  +29.9 percentage points and from  -5.0 to  +9.2 percentage points, respectively. CONCLUSION: the algorithms showed remarkable in-between differences when tested on raw-spectra from an 'ex vivo' model. All algorithms had bias, more marked at high oxygenation than low oxygenation. Three...

  15. Magnetocaloric effect of a series of remarkably isostructural intermetallic [Ni(II)3Ln(III)] cubane aggregates.

    Wang, Pei; Shannigrahi, Santiranjan; Yakovlev, Nikolai L; Hor, T S Andy


    A new series of remarkably isostructural 3d-4f compounds, [Ni3Ln(hmp)4(OAc)5]·H2O·CH2Cl2 (Ln = Gd (1), Tb (2), Dy (3), Ho (4), Y (5)) were synthesized based on a simple one-pot self-assembly method. Magnetic measurements demonstrated the ferromagnetic property of the [Ni3Ln] cores and the heterometallic influence on the magnetocaloric properties. This study suggested that robust and discrete intermetallic cubanes can be an alternative to other magnetically active materials such as high-nuclearity aggregates or clusters whose structures are not generally controlled by common synthetic methodological designs.

  16. Remarkable Dependence of the Final Charge Separation Efficiency on the Donor-Acceptor Interaction in Photoinduced Electron Transfer.

    Higashino, Tomohiro; Yamada, Tomoki; Yamamoto, Masanori; Furube, Akihiro; Tkachenko, Nikolai V; Miura, Taku; Kobori, Yasuhiro; Jono, Ryota; Yamashita, Koichi; Imahori, Hiroshi


    The unprecedented dependence of final charge separation efficiency as a function of donor-acceptor interaction in covalently-linked molecules with a rectilinear rigid oligo-p-xylene bridge has been observed. Optimization of the donor-acceptor electronic coupling remarkably inhibits the undesirable rapid decay of the singlet charge-separated state to the ground state, yielding the final long-lived, triplet charge-separated state with circa 100% efficiency. This finding is extremely useful for the rational design of artificial photosynthesis and organic photovoltaic cells toward efficient solar energy conversion.

  17. Some remarks on the time of flight and range of a projectile in a linear resisting medium

    S. M. Stewart


    Full Text Available In view of the recent work by Karkantzakos [Journal of Engineering Science and Technology Review 2 (2009 76–81], anumber of remarks highlighting the connection between the Lambert W function and the time of flight and range of a projectilemoving in a resisting medium where the retarding force acting on the projectile is proportional to its velocity are made.In particular, we show how each of these quantities can be expressed in closed form in terms of the Lambert W function andindicate how the analysis of the motion becomes greatly simplified by its introduction.

  18. “Are You From The Police, Or What?” Critical Remarks On Ethnographic Fieldwork Among (Disadvantaged) Urban Youth

    Gravesen, David Thore; Frostholm, Peter Hornbæk


    “Are You From The Police, Or What?” Critical Remarks On Ethnographic Fieldwork Among (Disadvantaged) Urban Youth As pointed out by Hammersley and Atkinson (2007) the field observer can experience being perceived as a spy and feeling undeniably unwelcome, especially in the beginning of observation...... and our role as non-SSP (a special Social services, School and Police unit) and non-police, we repeatedly experienced the youngsters questioning our presence. The confusion and skepticism that we experienced emphasized the importance of reflecting our position as researchers (Bourdieu 1999, Goodson...

  19. Axel Honneth: The law of freedom – Institutionalization of freedom in modern societies - A reconstruction and some remarks

    Rendtorff, Jacob Dahl


    This paper reconstructs the argument of Axel Honneth's recent book Das Recht der Freiheit as a theory of the institutionalization of freedom in modern society. In particular, it looks at Honneth's argument for the realization of freedom in law and morality that is proposed as a contemporary re......-interpretation of Hegel's Philosophy of Right. Then I discuss Honneth's argument for the reality of freedom in the ethical spheres of civil society, in particular in the family, the market and in democracy. Finally, the paper proposes some critical remarks to Honneth's theory....

  20. Remarks on neurocybernetics and its links to computing science. To the memory of Prof. Luigi M. Ricciardi.

    Moreno-Díaz, Roberto; Moreno-Díaz, Arminda


    This paper explores the origins and content of neurocybernetics and its links to artificial intelligence, computer science and knowledge engineering. Starting with three remarkable pieces of work, we center attention on a number of events that initiated and developed basic topics that are still nowadays a matter of research and inquire, from goal directed activity theories to circular causality and to reverberations and learning. Within this context, we pay tribute to the memory of Prof. Ricciardi documenting the importance of his contributions in the mathematics of brain, neural nets and neurophysiological models, computational simulations and techniques.

  1. Reply to ``Remarks on the simulation of Cl electrosorption on Ag(100) reported in Electrochimica Acta 50 (2005) 5518"

    Rikvold, P A; Hamad, I A; Mitchell, S J; Brown, G; Wandlowski, Th.


    We reply to remarks by Lang and Horanyi on the meaning of the notion of "electrosorption valency" used in I. Abou Hamad et al., Electrochim. Acta 50 (2005) 5518. It is concluded that, contrary to the assertion of Lang and Horanyi, the magnitude of the current in the external circuit upon adsorption of an ion of charge ze with partial charge transfer is indeed given by an electrosorption valency gamma such that |gamma e| < |ze|. We believe the conclusion of Lang and Horanyi to the contrary is the result of an excessively severe charge-neutrality requirement.

  2. A new subgenus and species of Topomyia (Diptera: Culicidae: Sabethini) based on a remarkable male mosquito from Sabah, Malaysia.

    Harbach, Ralph E; Culverwell, C Lorna


    Miyagiella Harbach, subgen. nov., is introduced as a new subgenus of Topomyia Leicester for a remarkable male mosquito, Topomyia discors Harbach, sp. nov., from Sabah, Malaysia. A diagnosis of the subgenus is provided that features unique anatomical characters of the genitalia of the holotype male. Miyagiella is very distinct from the two previously recognised subgenera of Topomyia, but is perhaps more closely related to the nominotypical subgenus than to subgenus Suaymyia Thurman. Salient differences that distinguish the three subgenera are contrasted; the holotype male of To. discors is described and its unique genitalia are illustrated.

  3. Synthesis of zeolite membranes

    JIANG Haiyang; ZHANG Baoquan; Y. S. Lin; LI Yongdan


    Zeolite membranes offer great application potentials in membrane separation and/or reaction due to their excellent separation performance and catalytic ability. Up to present, various synthesis methods of zeolite membranes have been developed, including embedded method,in-situ hydrothermal synthesis method, and secondary growth method etc. Compared with the in-situ hydrothermal synthesis method, the secondary growth method possesses a variety of advantages such as easier operation, higher controllability in crystal orientation, microstructure and film thickness, leading to much better reproducibility. This review provides a concise summary and analysis of various synthesis methods reported in the literature. In particular, the secondary growth method was discussed in detail in terms of crystal orientation, defects and crystal grain layers. Some critical issues were also highlighted, which were conducive to the improvement in the synthesis technology of zeolite membranes.

  4. VHDL for logic synthesis

    Rushton, Andrew


    Many engineers encountering VHDL (very high speed integrated circuits hardware description language) for the first time can feel overwhelmed by it. This book bridges the gap between the VHDL language and the hardware that results from logic synthesis with clear organisation, progressing from the basics of combinational logic, types, and operators; through special structures such as tristate buses, register banks and memories, to advanced themes such as developing your own packages, writing test benches and using the full range of synthesis types. This third edition has been substantially rewritten to include the new VHDL-2008 features that enable synthesis of fixed-point and floating-point hardware. Extensively updated throughout to reflect modern logic synthesis usage, it also contains a complete case study to demonstrate the updated features. Features to this edition include: * a common VHDL subset which will work across a range of different synthesis systems, targeting a very wide range of technologies...

  5. The origin of the universe and nuclear synthesis

    J. P. F. Sellschop


    Full Text Available The origin of the universe and nuclear synthesis are discussed in this paper. The concept of the “Big Bang” is introduced in cosmology from observational evidence that the universe is expanding. The language of elementary particle physics is used to describe the evolution of the universe starting at a very small fraction of a second after the "Big Bang”. Various “Eras” are identified during which certain nuclear processes predominate. At a later stage the remarkable nuclear synthesis of carbon takes place, leading to the evolution of other elements. Neutrino measurements are important to validate physical theories in this field and some results of such measurements by the WITS-CSIR Schonland Research Centre are presented.

  6. Synthesis and catalytic applications of combined zeolitic/mesoporous materials

    Jarian Vernimmen


    Full Text Available In the last decade, research concerning nanoporous siliceous materials has been focused on mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii the remarkable stability, catalytic activity and selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials. Focus is put on the synthesis and the applications of the combined zeolitic/mesoporous materials. The different synthesis approaches and formation mechanisms leading to these materials are comprehensively discussed and compared. Moreover, Ti-containing nanoporous materials as redox catalysts are discussed to illustrate a potential implementation of combined zeolitic/mesoporous materials.

  7. Polymerase engineering: towards the encoded synthesis of unnatural biopolymers.

    Loakes, David; Holliger, Philipp


    DNA is not only a repository of genetic information for life, it is also a unique polymer with remarkable properties: it associates according to well-defined rules, it can be assembled into diverse nanostructures of defined geometry, it can be evolved to bind ligands and catalyse chemical reactions and it can serve as a supramolecular scaffold to arrange chemical groups in space. However, its chemical makeup is rather uniform and the physicochemical properties of the four canonical bases only span a narrow range. Much wider chemical diversity is accessible through solid-phase synthesis but oligomers are limited to <100 nucleotides and variations in chemistry can usually not be replicated and thus are not amenable to evolution. Recent advances in nucleic acid chemistry and polymerase engineering promise to bring the synthesis, replication and ultimately evolution of nucleic acid polymers with greatly expanded chemical diversity within our reach.

  8. Sonochemical synthesis of zeolite NaP from clinoptilolite.

    Behin, Jamshid; Kazemian, Hossein; Rohani, Sohrab


    In the present work, natural clinoptilolite was converted to zeolite NaP using ultrasonic energy, in which the transformation time shortened remarkably. The effect of post-synthesis treatment using conventional hydrothermal was also investigated. The synthesized powders were characterized by XRD, TGA/DTA, SEM, and PSD analysis. The results showed that, increasing the sonication time (energy) has no significant effect on the product's morphology. The crystallinity of the synthesized samples increased slightly with increasing sonication time, but their yield remained relatively unchanged. Furthermore, post-synthesis hydrothermal treatment showed very little influence on properties of the final product. Because the ultrasonic irradiation creates acoustic cavitation cracks on the surface structure of clinoptilolite particulates and increases the concentration of soluble alumino-silicate species, which favors the prevailing super-saturation, crystallization and crystal growth of zeolite NaP happen faster. The particles of zeolite NaP synthesized by ultrasonic irradiation consist of small crystallites of uniform size.

  9. Visible light photocatalysis as a greener approach to photochemical synthesis.

    Yoon, Tehshik P; Ischay, Michael A; Du, Juana


    Light can be considered an ideal reagent for environmentally friendly, 'green' chemical synthesis; unlike many conventional reagents, light is non-toxic, generates no waste, and can be obtained from renewable sources. Nevertheless, the need for high-energy ultraviolet radiation in most organic photochemical processes has limited both the practicality and environmental benefits of photochemical synthesis on industrially relevant scales. This perspective describes recent approaches to the use of metal polypyridyl photocatalysts in synthetic organic transformations. Given the remarkable photophysical properties of these complexes, these new transformations, which use Ru(bpy)(3)(2+) and related photocatalysts, can be conducted using almost any source of visible light, including both store-bought fluorescent light bulbs and ambient sunlight. Transition metal photocatalysis thus represents a promising strategy towards the development of practical, scalable industrial processes with great environmental benefits.

  10. Effect of Temperature and Catalyst Concentration on Polyglycerol during Synthesis

    Carolina Ardila-Suárez


    Full Text Available Morphology, molecular weight, polydispersity, functionality, and thermal properties are important characteristics when using polyglycerol as a building block in the development of materials for industrial applications such as hydrogels, surfactants, asphalts additives, cosmetics, pharmaceutical, biomedical, and drug delivery systems. In this study several experimental techniques are used to understand the effect of process variables during synthesis in the catalyzed etherification of glycerol, a coproduct of biodiesel industry. Biobased polyglycerol is a high-valued product, which is useful as building block material because of its remarkable features, for instance, multiple hydrophilic groups, excellent biocompatibility, and highly flexible aliphatic polyether backbone. A connection between polyglycerol characteristics and process variables during synthesis allows the control of glycerol polymerization through reaction conditions. We show that temperature and catalyst concentration can be tuned with the aim of tailoring fundamental polyglycerol parameters including molecular weight, polydispersity, morphology, and functionality.

  11. Synthesis of a novel chemotype via sequential metal-catalyzed cycloisomerizations

    Bo Leng


    Full Text Available Sequential cycloisomerizations of diynyl o-benzaldehyde substrates to access novel polycyclic cyclopropanes are reported. The reaction sequence involves initial Cu(I-mediated cycloisomerization/nucleophilic addition to an isochromene followed by diastereoselective Pt(II-catalyzed enyne cycloisomerization.

  12. Synthesis of bicyclic guanidines via cascade hydroamination/Michael additions of mono-N-acryloylpropargylguanidines.

    Kwon, Ki-Hyeok; Serrano, Catherine M; Koch, Michael; Barrows, Louis R; Looper, Ryan E


    A cascade silver(I)-catalyzed hydroamination/Michael addition sequence has been developed to deliver highly substituted bicyclic guanidines. This transformation gives rise to geometrically and constitutionally stable ene-guanidines and generates a remote stereocenter with moderate to high diastereoselectivity.

  13. Asymmetric synthesis of the dibenzocyclooctadiene lignans interiotherin a and gomisin R.

    Coleman, Robert S; Gurrala, Srinivas Reddy


    [structure: see text] Asymmetric total syntheses of the dibenzocyclooctadiene lignans interiotherin A and angeloylgomisin R are reported. The syntheses were based on an atropdiastereoselective, copper-promoted biaryl coupling reaction, a diastereoselective hydroboration/Suzuki-Miyaura coupling reaction sequence, and an asymmetric boron-mediated tiglylation of an aryl aldehyde precursor.

  14. Synthesis of (Arylamido)pyrrolidinone Libraries through Ritter-Type Cascade Reactions of Dihydroxylactams

    Wu, Peng; Petersen, Michael Åxman; Petersen, Rico


    diastereoselectivity. A combined one-step Ritter–hydrolysis procedure proved to be of equal efficiency. This versatile method, which was successfully used for the construction of a screening library containing 706 molecules within the European Lead Factory consortium, provides a simple way to access new compounds...

  15. Eco-friendly synthesis, physicochemical studies, biological assay and molecular docking of steroidal oxime-ethers


    The aim of this study was to report the synthesis of biologically active compounds; 7-(2′-aminoethoxyimino)-cholest-5-ene (4), a steroidal oxime-ether and its derivatives (5, 6) via a facile microwave assisted solvent free reaction methodology. This new synthetic, eco-friendly, sustainable protocol resulted in a remarkable improvement in the synthetic efficiency (85–93 % yield) and high purity using basic alumina. The synthesized compounds were screened for their antibacterial against six bac...

  16. Tetra(acetylacetonato) tin(Ⅳ) as new catalyst for polytrimethylene terephthalate synthesis


    Chelate tetra(acetylacetonato) tin(Ⅳ) was prepared and used as catalyst for polytrimethylene terephthalate synthesis.It exhibited higher catalytic activity than tetrabutyl titanate,butyltinhydroxide oxide and dibutyltin oxide.Decrease in reaction time, content of terminal carboxyl group,color intensity and increase in intrinsic viscosity were observed.The unique molecular structure can be considered as factor remarkably improving the catalytic activity of tetra(acetylacetonato) tin(Ⅳ).

  17. Unfolding the Remarkable Orthopedic Surgeon. How to unleash the quest for excellence and the sense of caring.

    Rosinski, Philippe; Thienpont, Emmanuel


    Orthopedic surgery is a challenging profession, both at the diagnostic and therapeutic level. Successful treatment of patients requires teamwork with different stakeholders, with various personalities and motives. Coping with the stress of the quest for the ultimate surgical result might not be easy for everyone. While some surgeons see their activities as a job or at best as a career, others who face similar difficulties seem to respond to a higher calling. They are the ones striving for continuous improvement and excellence, and are committed to serving their patients with a deep sense of caring. In this article, we introduce a surgeon typology based on these two variables. We also introduce global coaching as a novel approach to help surgeons on this potentially transformational journey. We focus on the qualities that global coaching can help to develop as well as briefly mention some of the models and tools that can be called upon. Evidence from the Harvard Grant longitudinal study confirms that humans continue to develop during their adulthood and suggests that the following hypothesis is likely to be accurate: remarkable surgeons committed to technical excellence and caring deeply for their patients are likely to be most successful both in their careers and in their lives. If necessary, surgeons have a chance, a choice and a responsibility to change course, to reconnect with their profession and to establish more intimate relationships with their patients, colleagues as well as in their personal lives. By growing into becoming remarkable surgeons, they will serve others as well as themselves.

  18. Proclus' Elaboration of Platonic Remarks on the Problem of Evils, and their Relation to Divine Providence and Efficiency

    Reza korrang beheshti


    Full Text Available Although there is not a fully developed theory of evil in Plato, some various remarks are interspersed throughout his dialogues which provided the main materials for subsequent Platonists to elaborate a systematic doctrine of evil. Proclus is the most distinguished philosopher of the later Neoplatonism whose view became authoritative within the School and thus is most representative of the Neoplatonic doctrine of evil. By a critical assessment of the antecedent theories of evil, Proclus attempts to give a monistic interpretation of Platonic remarks on the problem of evil. According to his explanation, the higher degrees and principles of Being are only and purely good and are not the causes of evils but the good things for all things alone. Evils, however, exist necessarily but only among particular beings in a relative, parasitic, accidental way and dependent upon the good. The parasitic accidental existence of evil does not have a real efficient cause. It arises due to an asymmetry between the activities of the several faculties or powers of a complex particular being. Moreover, the existence of evil is so mixed with and dependent upon the good that despite its opposition to the good, contributes, in its own manner, to the fulfillment of goodness of the whole Universe, being thus reconcilable with Divine Providence and Efficiency.

  19. Simple Fabrication of Mesoporous Silica with Remarkable High Temperature Stability at Neutral pH and Ambient Conditions from TEOS

    Hess, David; Vippagunta, Radha; Watkins, James


    Traditional silica synthesis processes can yield well ordered materials, but the synthesis conditions also lead to incomplete condensation of the silica network, which results in significant structural contraction upon calcination and limited thermal, hydrothermal and mechanical stability. Here we report the synthesis that, surprisingly, yields nearly complete condensation of the silica network (virtually all Q4 linkages) using cysteamine as the catalyst and polyoxyethylene surfactants as the structure directing agents in buffered solution at neutral pH and ambient temperature. Recently, small molecule bifunctional amines, including cysteamine, were evaluated by Morse and co-workers and found to produce silica from TEOS(JACS 2005, 127, 35). Our work combines the cysteamine catalyst system with structure-directing block copolymer surfactants at neutral pH and ambient temperature to produce mesoporous silica. The addition of tetraethyl orthosilicate (TEOS) to a solution of containing cysteamine, citrate buffer (pH 7.2) and 5wt Brij amphiphilic block copolymer (polyethylene oxide-polyethylene) yields mesoporous silica. The resulting mesoporous silica powder was analyzed using XRD, TGA, FTIR, TEM, and NMR. The materials were found to exhibit stability under extreme temperature calcinations (up to 800 C) in the presence of water. SAXS shows that 1.0 shrinkage upon calcination up to 800C. 29Si NMR analysis indicates a fully condensed silica network, Q4 linkages, in accordance with this observation.

  20. Silica Synthesis by Sponges: Unanticipated Molecular Mechanism

    Morse, D. E.; Weaver, J. C.


    Oceanic diatoms, sponges and other organisms synthesize gigatons per year of silica from silicic acid, ultimately obtained from the weathering of rock. This biogenic silica exhibits a remarkable diversity of structures, many of which reveal a precision of nanoarchitectural control that exceeds the capabilities of human engineering. In contrast to the conditions of anthropogenic and industrial manufacture, the biological synthesis of silica occurs under mild physiological conditions of low temperatures and pressures and near-neutral pH. In addition to the differentiation between biological and abiotic processes governing silica formation, the biomolecular mechanisms controlling synthesis of these materials may offer insights for the development of new, environmentally benign routes for synthesis of nanostructurally controlled silicas and high-performance polysiloxane composites. We found that the needle-like silica spicules made by the marine sponge, Tethya aurantia, each contain an occluded axial filament of protein composed predominantly of repeating assemblies of three similar subunits we named "silicateins." To our surprise, analysis of the purified protein subunits and the cloned silicatein DNAs revealed that the silicateins are highly homologous to a family of hydrolytic enzymes. As predicted from this finding, we discovered that the silicatein filaments are more than simple, passive templates; they actively catalyze and spatially direct polycondensation to form silica, (as well as the phenyl- and methyl-silsesquioxane) from the corresponding silicon alkoxides at neutral pH and low temperature. Catalytic activity also is exhibited by the silicatein subunits obtained by disaggregation of the protein filaments and those produced from recombinant DNA templates cloned in bacteria. This catalytic activity accelerates the rate-limiting hydrolysis of the silicon alkoxide precursors. Genetic engineering, used to produce variants of the silicatein molecule with

  1. Asymmetric synthesis v.4

    Morrison, James


    Asymmetric Synthesis, Volume 4: The Chiral Carbon Pool and Chiral Sulfur, Nitrogen, Phosphorus, and Silicon Centers describes the practical methods of obtaining chiral fragments. Divided into five chapters, this book specifically examines initial chiral transmission and extension. The opening chapter describes the so-called chiral carbon pool, the readily available chiral carbon fragments used as building blocks in synthesis. This chapter also provides a list of 375 chiral building blocks, along with their commercial sources, approximate prices, and methods of synthesis. Schemes involving

  2. Mechanochemical organic synthesis.

    Wang, Guan-Wu


    Recently, mechanical milling using a mixer mill or planetary mill has been fruitfully utilized in organic synthesis under solvent-free conditions. This review article provides a comprehensive overview of various solvent-free mechanochemical organic reactions, including metal-mediated or -catalyzed reactions, condensation reactions, nucleophilic additions, cascade reactions, Diels-Alder reactions, oxidations, reductions, halogenation/aminohalogenation, etc. The ball milling technique has also been applied to the synthesis of calixarenes, rotaxanes and cage compounds, asymmetric synthesis as well as the transformation of biologically active compounds.

  3. Hydrothermal organic synthesis experiments

    Shock, Everett L.


    Ways in which heat is useful in organic synthesis experiments are described, and experiments on the hydrothermal destruction and synthesis of organic compounds are discussed. It is pointed out that, if heat can overcome kinetic barriers to the formation of metastable states from reduced or oxidized starting materials, abiotic synthesis under hydrothermal conditions is a distinct possibility. However, carefully controlled experiments which replicate the descriptive variables of natural hydrothermal systems have not yet been conducted with the aim of testing the hypothesis of hydrothermal organic systems.

  4. Experimental Aspects of Synthesis

    Ehlers, Rüdiger


    We discuss the problem of experimentally evaluating linear-time temporal logic (LTL) synthesis tools for reactive systems. We first survey previous such work for the currently publicly available synthesis tools, and then draw conclusions by deriving useful schemes for future such evaluations. In particular, we explain why previous tools have incompatible scopes and semantics and provide a framework that reduces the impact of this problem for future experimental comparisons of such tools. Furthermore, we discuss which difficulties the complex workflows that begin to appear in modern synthesis tools induce on experimental evaluations and give answers to the question how convincing such evaluations can still be performed in such a setting.

  5. Exploring the Scope of Asymmetric Synthesis of β-Hydroxy-γ-lactams via Noyori-type Reductions.

    Lynch, Denis; Deasy, Rebecca E; Clarke, Leslie-Ann; Slattery, Catherine N; Khandavilli, U B Rao; Lawrence, Simon E; Maguire, Anita R; Magnus, Nicholas A; Moynihan, Humphrey A


    Enantio- and diastereoselective hydrogenation of β-keto-γ-lactams with a ruthenium-BINAP catalyst, involving dynamic kinetic resolution, has been employed to provide a general, asymmetric approach to β-hydroxy-γ-lactams, a structural motif common to several bioactive compounds. Full conversion to the desired β-hydroxy-γ-lactams was achieved with high diastereoselectivity (up to >98% de) by addition of catalytic HCl and LiCl, while β-branching of the ketone substituent demonstrated a pronounced effect on the modest to excellent enantioselectivity (up to 97% ee) obtained.

  6. Plenary presentations - opening remarks

    Simon, R.M.


    I am pleased to be here today as one of the U.S. Co-Chairs for the Second U.S./Japan Workshop on Global Change. This series of workshops is an outgrowth of the 1988 bilateral agreement between the U.S. and Japanese governments on scientific and technological cooperation. That agreement called for comparable access to, and exchange of, information in scientific and technological fields, as well as the joint undertaking of cooperative activities for peaceful purposes in nationally important areas of science and technology. Meetings such as this were envisioned under the agreement to allow experts from both sides to discuss and exchange information on scientific and technological aspects of important problems and to identify research and development projects that might usefully be undertaken on a cooperative basis. The first U.S./Japan Workshop on Global Change focused on research needed to better understand how the global climate system operates, what the interactions are between the climate system and marine and terrestrial ecosystems, and how Earth systems might respond to global climatic changes.

  7. Remarks on hamiltonian digraphs

    Gutin, Gregory; Yeo, Anders


    This note is motivated by A.Kemnitz and B.Greger, Congr. Numer. 130 (1998)127-131. We show that the main result of the paper by Kemnitz and Greger is an easy consequence of the characterization of hamiltonian out-locally semicomplete digraphs by Bang-Jensen, Huang, and Prisner, J. Combin. Theory...... of Fan's su#cient condition [5] for an undirected graph to be hamiltonian. In this note we give another, more striking, example of this kind, which disproves a conjecture from [6]. We also show that the main result of [6] 1 is an easy consequence of the characterization of hamiltonian out......-tournaments by Bang-Jensen, Huang and Prisner [4]. For further information and references on hamiltonian digraphs, see e.g. the chapter on hamiltonicity in [1] as well as recent survey papers [2, 8]. We use the standard terminology and notation on digraphs as described in [1]. A digraph D has vertex set V (D) and arc...

  8. Concluding Remarks%序

    Sunney I.Chan


    @@ Thank you for your kind introduction, T.L. I am, of course, honored to have been the Honorary Chairman of ISOC 4, and I thank the Organizing Committee for bestowing this honoron me. As you know, I am not a card- carrying organic chemist, and one might wonder what a physical biochemist could really contribute to this Symposium. But, as Professor Chi - Huey Wong noted during his keynote address, I am over the hill in my own field. Perhaps, my colleagues at CUHK think I might be able to begin a second career as an organic chemist. Lest you question the seriousness of this suggestion, my students and I have recently published in the Journal of Organic Chemistry and Tetrahedron Letters!

  9. One remarkable molecule: filaggrin.

    Brown, Sara J; McLean, W H Irwin


    The discovery, in 2006, that loss-of-function mutations in the filaggrin (FLG) gene are the cause of ichthyosis vulgaris-the most common disorder of keratinization-and also a strong genetic risk factor for atopic eczema, marked a significant breakthrough in the understanding of eczema pathogenesis. Subsequent investigations of the role of FLG-null mutations have identified a series of significant associations with atopic disease phenotypes, including atopic asthma, allergic rhinitis, and peanut allergy. However, many questions remain to be answered in relation to the precise mechanisms by which deficiency of an intracellular protein expressed primarily in the differentiating epidermis may contribute to the development of cutaneous and systemic pathology. This review aims to highlight the key milestones in filaggrin research over the past 25 years, to discuss the mechanistic, clinical, and therapeutic implications, and to consider possible future directions for ongoing investigation.

  10. Remarks on Higgs Inflation

    Atkins, Michael


    We discuss models where the Higgs boson of the electroweak standard model plays the role of the inflaton. We focus on the question of the violation of perturbative unitarity due to the coupling of the Higgs boson either to the Ricci scalar or to the Einstein tensor and discuss the background dependence of the unitarity bounds. Our conclusion is that the simplest model which restricts itself to the standard model Higgs boson without introducing further degrees of freedom has a serious problem. However, in the asymptotically safe gravity scenario, the Higgs boson of the standard model could be the inflaton and no physics beyond the standard model is required to explain both inflation and the spontaneous breaking of the electroweak symmetry of the standard model.

  11. Remarks on numerical semigroups

    Torres, F


    We extend results on Weierstrass semigroups at ramified points of double covering of curves to any numerical semigroup whose genus is large enough. As an application we strengthen the properties concerning Weierstrass weights in \\cited{To}.


    Chu Yuming; Cheng Jinfa; Wang Gendi


    Let D R2 be a Jordan domain, D* = -R2 \\ -D, the exterior of D. In this article, the authors obtained the following results: (1) If D is a John disk, then D is an outer linearly locally connected domain; (2) If D* is a John disk, then D is an inner linearly locally connected domain; (3) A homeomorphism f: R2→R2 is a quasiconformal mapping if and only if f(D) is a John disk for any John disk D(∈)R2; and (4) If D is a bounded quasidisk, then D is a John disk, and there exists an unbounded quasidisk which is not a John disk.

  13. Monograph: Concluding Remarks

    Ajai R. Singh


    Full Text Available Private investment in biomedical research has increased over the last few decades. At most places it has been welcomed as the next best thing to technology itself. There are significant costs involved too. Major areas of conflict of interest especially applicable to biomedical research have arisen, as academia interacts with industry. Pharma image stinks because of a number of errors of omission and commission. A recent example is suppression of negative findings about Bayer's Trasylol (Aprotinin and the marketing maneuvers of Eli Lilly's Xigris (rhAPC. A voluntary moratorium over pharma spending to pamper drug prescribers is necessary.The integrity of industry-sponsored clinical research has come under increasing scrutiny. The basic shizm is between the value system of a patient welfare driven professional and that of a profit driven industry . While one wants to avoid control but wants the dough, the other wants to exercise the control by supplying the dough. Clinical practice guidelines (CPG are considered important as they guide diagnostic/therapeutic regimen of a large number of medical professionals and hospitals and provide recommendations on drugs, dosages and criteria for selection. Besides clinical trials, they are another area of growing influence by the pharmaceutical industry. For example, in a recent survey it was found that about 60% of 192 authors of clinical practice guidelines reported they had financial connections with the companies whose drugs were under consideration. This finding casts serious doubt on the credibility of this important pillar of modern clinical practice. It needs urgent reparative action. One of them is prospective and retrospective disclosure of financial conflict of interest by authors of CPGs.A Conference on Guideline Standardization (COGS was convened in April 2002 'to define a standard for guideline reporting that would promote guideline quality and facilitate implementation'. It includes items for standardization, conceptual issues, up gradation, conflict of interest, patient interest and systematization. Even items for individual preferences, choice or values are not neglected. Special mention must be made of items that specify disclosure of conflict of interest both in the Developer (including the organization that develops and the individuals involved in the guideline's formulation, as well as in the sponsor or funding source (and its role in developing and/or reporting the guideline.Recommendations of CPGs and CDR panels are conflicting. One considers effectiveness, the other cost-effectiveness. However, CPGs do not adhere to established methodological standards; critical information that would attest to validity is regularly absent; explicit criteria to grade scientific evidence that supports their recommendations is absent from 82% of guidelines; 87% are not in a position to report whether a systematic literature search was performed; 67% do not describe the type of professionals used in guidelines development; and there is marked variation in the quality of guidelines. Moreover, CPG guideline layers often are conflicted in their interests. The problem can be resolved to a large extent by taking a simple step: making CPG panelists go into cost effectiveness along with recommending Guidelines. What then happens is they have to consider not only effectiveness but also costs. Effectiveness can be fudged, cost cannot. Why? Because, what is the cost is well known. Therapies in Guidelines should be recommended and graded according to whether they are Most, Moderately or Least Cost Effective. For that CPGs will have to perform an economic analysis as well. This will meet with resistance for obvious reasons. Since guideline groups cannot be kept on the straight and narrow path and till we find fool proof ways of keeping them thus, we have no option but to stress that under no circumstances they can mislead, or get misled themselves, in the name of patient advocacy, to recommend costly new therapies which have still not proved their effectiveness conclusively, nor get away with conflicted recommendations, which it is still not obligatory to reveal. A simple rider like making it mandatory for guideline groups to go into both effectiveness and cost effectiveness takes care that this is ensured.The AGREE Collaboration (AGREE stands for Appraisal of Guidelines, Research and Evaluation has created and validated tools by which clinicians can themselves rate guidelines by identifying factors that determine their quality. To facilitate this process, a body like the GAC (Guidelines Advisory Committee applies the AGREE criteria to individual guidelines and rates and endorses the best possible guideline. Clinical Practice Guidelines are another example of an excellent idea likely to go to seed due to sponsor manipulation and forces of the market place camouflaging as evidence based medicine. The need to weed out conflicted experts and make the process of therapy selection transparent must go hand in hand with laying down clear-cut criteria for guideline formulation and rejection of conflicted submissions by vigilant journal publication policies and editors. A number of disease-specific foundations are heavily funded by industry that creates serious conflict of interest likely to result in favourably recommending therapies of sponsors. The case of Alteplase and the American Heart Foundation is a recent example. Whistle blowing papers and research to expose misdemeanours must be undertaken and journals and their editors should welcome such papers as legitimate research, without encouraging a witch-hunt. The USP of journals and researchers is credibility. Credibility can be marketed, but it can't be bought. Sponsors will be forced to seek such credibility without allowing them to compromise it. Such is the game journal publishers/editors and genuine researchers will have to play with sponsors. But they can do so only if they are thoroughly competent and have abiding faith in an uncompromising set of ethical values. The Task Force of the AAMC, in its two reports of 2001 and 2002, recognises the necessity and inevitability of the academia-industry connect, but wants to avoid its undesirable influence on the integrity of research and the welfare of human research subjects. It is specially concerned that public, activist and governmental control and concern does not cast a spanner in the works of a potentially promising relationship.Constant pampering by sponsors has dulled most drug prescribers' critical capabilities. Sponsorship is a potent anaeasthetic to many ethical concerns. It can blunt the thrust of many a sabre-rattling critic.Both medical associations and research journal editors are getting concerned with individual and institutional conflicts of interest in the conduct of clinical research and documents are now available which address these issues.Edits are concerned with whether academic medicine is for sale (Angell, in N Engl J Med 2000; what are the controlling interests of research (Editorial, CMAJ, 2002a; how the invisible hand of the marketing department works (Editorial, CMAJ , 2002b; how contracts affect institutions and academic freedom (Drazen in N Engl J Med , 2002; what are the choices for the academic medical center in collaborating with industry - (Moses et al in N Engl J Med , 2002; how does one ensure integrity of scientific research (Editorial, Lancet , 2002; how one maintains public trust in clinical research (Kelch in N Engl J Med , 2002; how does one ensure academic freedom in clinical research (Nathan and Weatherall, editorial, in N Engl J Med 2002; how to maintain the integrity of the scientific record (Smith R.: [editorial]. BMJ 2001; and is the university-industrial complex going out of control? ( Nature , 2001. The 2001 ICMJE revision call for full disclosure of the sponsor's role in research, as well as assurance that investigators are independent of sponsors, are fully accountable for the design and conduct of the trial, have independent access to all trial data and control all editorial and publication decisions. ICMJE has taken an important step in ensuring greater accountability in the research process, its publication and preventing possible malevolent impact on gullible readers. However the findings of a 2002 study suggest that academic institutions routinely participate in clinical research that does not adhere to ICMJE standards of accountability, access to data and control of publication. An issue of major concern is protection of the interests of research subjects because patients agree to become research subjects not only for personal medical benefit but, as an extension, to benefit the rest of the patient population and also advance medical research. These interests are hardly served if research data is doctored or concealed, as can happen to protect industry interests or if industry dictates the terms and conditions of research contracts.The progress of biomedical research depends on ready availability of research subjects. But such ready availability depends on ethical practices by researchers and sponsoring agencies. The clear-cut power to protect research subjects' interests should be inbuilt in the contract process. Establishment of Best Practice Guidelines for researchers and academic medical centers and Good Publication Practice for sponsoring pharmaceuticals are two important developments worth a close study and replication to assess feasibility across diverse geographical areas. Another area of concern is pharma's focus on the marketability rather than usefulness of products. There is an inevitable slant to produce not necessarily useful but marketable products which ensure profitability of industry and research grants outflow to academia. A disturbing but very relevant finding in this connection is that drugs which can be called "substantial improvements" over available treatments is only, mark the finding, a measly 6%. Industry supports new therapies, not traditional therapy, irrespective of what is effective. Whatever traditional therapy is supported is also most probably because the industry concerned has a product with a big stake there, which has remained a 'gold standard' or which that player thinks still has some 'juice' left.The larger issue of benefit to society also concerns us here when we realize that industry sponsorship is mainly for potential medications, not for trying to determine whether there may be non-pharmacological interventions that may be equally good, if not better. This is the reason why methods like yoga, psychotherapy, meditation, non-medicated non-mechanised relaxation will not find industry sponsors readily and will never be proved useful apart from anecdotal reporting.In the paradigm shift towards biological psychiatry, the role of industry sponsorship is not overt but probably more pervasive than many have realized or the right thinking may consider good for the health of the branch in the long run. Ask yourself a simple question: Why should industry sponsor psychotherapeutic research? And why should industry not sponsor biological research? Which of the two will give rise to drugs? How will the profits pour in? The answer is simple enough.Essentially, there are four types of drugs. First, drugs that work and have minimal side-effects; second, drugs which work but have serious side-effects; third, drugs that do not work but have minimal side-effects; and fourth, drugs which work minimally but have serious side-effects. Pharma's major propelling force can only be producing the first type. They accept the second type only till they can lay their hands on the first and, in any case, never project or accept them as the first. The third type can be occasionally played around with to shore up profits, but never by projecting them as the first type. The fourth type are the laggards, a real threat to credibility and therefore do not deserve any market hype or promotion. What makes pharma adopt even questionable means to make profits? Reasons are mainly three: one, pharma business cannot depend only on genuine discoveries; second, newer drugs with no effect are also with no, or little, side-effects - and that helps; and third, image building needs to balance profit with shored up credibility. Industry players have to strike the right balance between profit making and credibility. In profit making, the marketing champions play their role. In credibility ratings, researchers and paid spokes-persons play their role. All is hunky dory till marketing is based on credibility. When there is nothing available to make for credibility, something is projected as one and marketing carried out, in the calculated hope that profits can accrue, since that must continue endlessly. That is what makes pharma adopt even questionable means to make profits.The process of self-correction set into motion due to greater clout of conscientious researchers, unrelenting expose by medical journalists and supportive editors, patients right activism and law suits against industry will, hopefully, help tilt the balance towards value-based advance, even if belated, and done grudgingly. Major industry players may soften the offensive of such self-correction only by playing the game according to the rules. The earlier the major players understand this, the better it is for all concerned.

  14. Remarks on American Taboos



    Language serves as the tool of communication between people.In any language persons,things and activities that are ta⁃boos should not be talked about or should be mentioned in a roundabout way. it is not only a linguistic phenomenon but also a social phenomenon.The origin of taboo is deeply rooted in the social and cultural background. Today in the increasingly frequent cross-cultural communication, if you do not understand the language taboos, it will hinder the smooth communication. This pa⁃per will talk about American taboos from two aspects.It is designed to help English learners understand American culture and im⁃prove competence of cross-cultural communication.

  15. A remarkable legacy

    Parkinson, Stuart


    Joseph Rotblat, who died in 2005 at the age of 96, was a rare combination of distinguished scientist and leading peace advocate. During the Second World War he was involved with the Manhattan Project - which created the world's first atomic bombs - but then decided to resign on ethical grounds. This life-changing decision set the scene for the dual role that he would play for the rest of his life. On the one hand, Rotblat was a key figure in setting up and leading the Pugwash Conferences on Science and World Affairs, which bring together scientists and public figures concerned with reducing the danger of armed conflict and seeking co-operative solutions for global problems. On the other, he was an accomplished nuclear and medical physicist, eventually becoming president of the British Institute of Radiology.

  16. Remarks on Eisenstein

    Bilu, Yuri


    We obtain a fully explicit quantitative version of the Eisenstein theorem on algebraic power series which is more suitable for certain applications than the existing version due to Dwork, Robba, Schmidt and van der Poorten. We also treat ramified series and Laurent series, and we demonstrate some applications; for instance, we estimate the discriminant of the number field generated by the coefficients.

  17. Mathematics Admission Test Remarks

    Ideon Erge


    Full Text Available Since 2014, there have been admission tests in mathematics for applicants to the Estonian University of Life Sciences for Geodesy, Land Management and Real Estate Planning; Civil Engineering; Hydraulic Engineering and Water Pollution Control; Engineering and Technetronics curricula. According to admission criteria, the test must be taken by students who have not passed the specific mathematics course state exam or when the score was less than 20 points. The admission test may also be taken by those who wish to improve their state exam score. In 2016, there were 126 such applicants of whom 63 took the test. In 2015, the numbers were 129 and 89 and in 2014 150 and 47 accordingly. The test was scored on scale of 100. The arithmetic average of the score was 30.6 points in 2016, 29.03 in 2015 and 18.84 in 2014. The test was considered to be passed with 1 point in 2014 and 20 points in 2015 and 2016. We analyzed test results and gave examples of problems which were solved exceptionally well or not at all.

  18. Elaboration of Sterically Hindered δ-Lactones through Ring-Closing Metathesis: Application to the Synthesis of the C1-C27 Fragment of Hemicalide.

    Lecourt, Camille; Boinapally, Srikanth; Dhambri, Sabrina; Boissonnat, Guillaume; Meyer, Christophe; Cossy, Janine; Sautel, François; Massiot, Georges; Ardisson, Janick; Sorin, Geoffroy; Lannou, Marie-Isabelle


    The synthesis of the C1-C27 fragment of hemicalide, a marine metabolite displaying a unique potent antiproliferative activity, has been accomplished. The synthetic approach highlights a remarkably efficient ring-closing metathesis reaction catalyzed by Nolan ruthenium indenylidene complexes to elaborate the highly substituted δ-lactone framework.

  19. Protein Synthesis-Dependent Long-Term Memory Induced by One Single Associative Training Trial in the Parasitic Wasp Lariophagus distinguendus

    Steidle, Johannes L. M.; Collatz, Jana; Muller, Caroline


    Protein synthesis-dependent long-term memory in Apis mellifera and Drosophila melanogaster is formed after multiple trainings that are spaced in time. The parasitic wasp Lariophagus distinguendus remarkably differs from these species. It significantly responds to the artificial odor furfurylheptanoate (FFH) in olfactometer experiments, when this…

  20. Generalised Rabin(1) synthesis

    Ehlers, Ruediger


    We present a novel method for the synthesis of finite state systems that is a generalisation of the generalised reactivity(1) synthesis approach by Piterman, Pnueli and Sa'ar. In particular, we describe an efficient method to synthesize systems from linear-time temporal logic specifications for which all assumptions and guarantees have a Rabin index of one. We show how to build a parity game with at most five colours that captures all solutions to the synthesis problem from such a specification. This parity game has a structure that is amenable to symbolic implementations. We furthermore show that the results obtained are in some sense tight, i.e., that there does not exist a similar synthesis method for assumptions and specifications of higher Rabin index, unless P=NP.

  1. Catalytic Synthesis Lactobionic Acid

    V.G. Borodina


    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  2. Synthesis of Acetylhomoagmatine

    Carmenza Duque


    Full Text Available Abstract: The first total synthesis of acetylhomoagmatine, a natural product isolated form the methanolic extracts from the sponge Cliona celata, is performed in four steps in a very high yield.

  3. Synthesis and morphology research of framework Ti-rich TS-1 containing no extraframework Ti species in the presence of CO2

    Zhu, Guowei


    A new method to synthesis TS-1 has been developed using the carbon dioxide (CO2) as an alkalinity regulator that resulted in the increased framework Ti contents. The prepared catalyst had a Si/Ti ratio as low as 40 in contrast to the ratio of 56 prepared through conventional synthesis. The twin crystals with the length of 2 μm were formed via introduction of CO 2. The catalytic activity of TS-1 is remarkably enhanced compared with the conventional synthesis. © 2013 Elsevier B.V.

  4. Protecting the herd: the remarkable effectiveness of the bacterial meningitis polysaccharide-protein conjugate vaccines in altering transmission dynamics.

    Stephens, David S


    Interrupting human-to-human transmission of the agents (Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae) of bacterial meningitis by new capsular polysaccharide-protein conjugate vaccines (PPCVs) has proven to be a remarkable (and unanticipated) contributor to vaccine effectiveness. Herd immunity accounts for ∼50% of the protection by meningococcal serogroup C PPCVs, pneumococcal PPCV7, and H. influenzae b PPCVs. Nasopharyngeal carriage can be reduced ≥75% for vaccine serotypes; the decrease in carriage is correlated with disease reduction in unvaccinated individuals, and the impact of herd immunity lasts for years. Based on these data, models for using herd immunity in vaccine-based prevention strategies are underway for control of meningitis in sub-Saharan Africa. Although the immunologic basis of herd immunity and impact on microbial biology need more study, protecting the unvaccinated by altering pathogen transmission dynamics is a powerful effect of PPCVs and increasingly important in vaccine introduction, implementation, and evaluation strategies.


    赵鹏; 张绍英; 张宏伟; 阎阿儒; 沈保根


    The melt-spinning process has been carried out to improve the hard-magnetic properties of the TbMn6Sn6 compound. For the TbMn6Sn6 ribbons quenched at a rate of 40m/s and annealed at 545K for 30min, the highest coercivity of about 0.6T is achieved at room temperature, which is much higher than that of the TbMn6Sn6 ingot. Both the ingot and the ribbon coercivities will increase with decreasing temperature. For ribbons, a greater improvement of coercivity has been made at lower temperatures. Microstructural studies show the uniform nanocrystalline distribution in the TbMn6Sn6 ribbons and a small amount of Tb-rich phase in grain boundaries. The observed remarkable improvement of magnetic hardening in ribbons is believed to arise from the uniform nanoscale microstructure and the domain-wall pinning at the grain boundaries.

  6. Remarkable Improvement of Nail Changes in Alopecia Areata Universalis with 10 Months of Treatment with Tofacitinib: A Case Report

    Ferreira, Sineida Berbert; Scheinberg, Morton; Steiner, Denise; Steiner, Tatiana; Bedin, Gustavo Longhi; Ferreira, Rachel Berbert


    Alopecia areata (AA) is a chronic, autoimmune disease. The main symptom is massive hair loss, localized or diffuse, in the scalp and the whole body. However, nails may also be involved, and brittleness, fragility and pitting can be signs of nail dystrophy in AA patients. Here, we report the case of a male patient with AA refractory to various treatments, including oral, topical and intralesional corticosteroids, immunosuppressants, cyclosporin and PUVA (oxoralen plus ultraviolet light), all interrupted due to side effects. The patient's nails had erythematous blotches (striated lunulae) with regular and superficial pitting as well as fragility (trachyonychia), and he could no longer play the guitar because of these symptoms. With patient consent, we introduced tofacitinib (5 mg twice daily), which resulted in remarkable improvements not only regarding hair regrowth but also nail changes, with function recovery within 10 months. PMID:28101018

  7. First remarks on the nesting biology of Hypodynerus andeus (Packard (Hymenoptera, Vespidae, Eumeninae in the Azapa valley, northern Chile

    Felipe Méndez-Abarca


    Full Text Available First remarks on the nesting biology of Hypodynerus andeus (Packard (Hymenoptera, Vespidae, Eumeninae in the Azapa valley, northern Chile. Some aspects about the nesting biology of the potter wasp Hypodynerus andeus (Packard, 1869 are reported for the first time. Observations were carried out at the Azapa valley, coastal desert of northern Chile. A total of sixty nests were collected and examined, each composed by 1-14 cells, most of them found attached to concrete lamp posts. The only preys recorded in the cells were Geometridae (Lepidoptera caterpillars and the presence of the parasitoid Anthrax sp. (Diptera, Bombyliidae was also recorded. A number of arthropods belonging to different groups, mainly spiders, were found occupying empty nests.

  8. Speech Compression and Synthesis


    phonological rules combined with diphone improved the algorithms used by the phonetic synthesis prog?Im for gain normalization and time... phonetic vocoder, spectral template. i0^Th^TreprtTörc"u’d1sTuV^ork for the past two years on speech compression’and synthesis. Since there was an...from Block 19: speech recognition, pnoneme recogmtion. initial design for a phonetic recognition program. We also recorded ana partially labeled a

  9. Instrument Modeling and Synthesis

    Horner, Andrew B.; Beauchamp, James W.

    During the 1970s and 1980s, before synthesizers based on direct sampling of musical sounds became popular, replicating musical instruments using frequency modulation (FM) or wavetable synthesis was one of the “holy grails” of music synthesis. Synthesizers such as the Yamaha DX7 allowed users great flexibility in mixing and matching sounds, but were notoriously difficult to coerce into producing sounds like those of a given instrument. Instrument design wizards practiced the mysteries of FM instrument design.

  10. Parallelizing quantum circuit synthesis

    Di Matteo, Olivia; Mosca, Michele


    Quantum circuit synthesis is the process in which an arbitrary unitary operation is decomposed into a sequence of gates from a universal set, typically one which a quantum computer can implement both efficiently and fault-tolerantly. As physical implementations of quantum computers improve, the need is growing for tools which can effectively synthesize components of the circuits and algorithms they will run. Existing algorithms for exact, multi-qubit circuit synthesis scale exponentially in t...

  11. Self-assembled thin film of imidazolium ionic liquid on a silicon surface: Low friction and remarkable wear-resistivity

    Gusain, Rashi [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Academy of Scientific and Innovative Research, New Delhi 110025 (India); Kokufu, Sho [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Bakshi, Paramjeet S. [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Khatri, Om P., E-mail: [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Academy of Scientific and Innovative Research, New Delhi 110025 (India)


    Graphical abstract: - Highlights: • Ionic liquid thin film is deposited on a silicon surface via covalent interaction. • Chemical and morphological features of ionic liquid thin film are probed by XPS and AFM. • Ionic liquid thin film exhibited low and steady friction along with remarkable wear-resistivity. - Abstract: Imidazolium-hexafluorophosphate (ImPF{sub 6}) ionic liquid thin film is prepared on a silicon surface using 3-chloropropyltrimethoxysilane as a bifunctional chemical linker. XPS result revealed the covalent grafting of ImPF{sub 6} thin film on a silicon surface. The atomic force microscopic images demonstrated that the ImPF{sub 6} thin film is composed of nanoscopic pads/clusters with height of 3–7 nm. Microtribological properties in terms of coefficient of friction and wear-resistivity are probed at the mean Hertzian contact pressure of 0.35–0.6 GPa under the rotational sliding contact. The ImPF{sub 6} thin film exhibited low and steady coefficient of friction (μ = 0.11) along with remarkable wear-resistivity to protect the underlying silicon substrate. The low shear strength of ImPF{sub 6} thin film, the covalent interaction between ImPF{sub 6} ionic liquid thin film and underlying silicon substrate, and its regular grafting collectively reduced the friction and improved the anti-wear property. The covalently grafted ionic liquid thin film further shows immense potential to expand the durability and lifetime of M/NEMS based devices with significant reduction of the friction.

  12. Remarkable induction of UV-signature mutations at the 3'-cytosine of dipyrimidine sites except at 5'-TCG-3' in the UVB-exposed skin epidermis of xeroderma pigmentosum variant model mice.

    Ikehata, Hironobu; Chang, Yumin; Yokoi, Masayuki; Yamamoto, Masayuki; Hanaoka, Fumio


    The human POLH gene is responsible for the variant form of xeroderma pigmentosum (XP-V), a genetic disease highly susceptible to cancer on sun-exposed skin areas, and encodes DNA polymerase η (polη), which is specialized for translesion DNA synthesis (TLS) of UV-induced DNA photolesions. We constructed polη-deficient mice transgenic with lacZ mutational reporter genes to study the effect of Polh null mutation (Polh(-/-)) on mutagenesis in the skin after UVB irradiation. UVB induced lacZ mutations with remarkably higher frequency in the Polh(-/-) epidermis and dermis than in the wild-type (Polh(+/+)) and heterozygote. DNA sequences of a hundred lacZ mutants isolated from the epidermis of four UVB-exposed Polh(-/-) mice were determined and compared with mutant sequences from irradiated Polh(+)(/)(+) mice. The spectra of the mutations in the two genotypes were both highly UV-specific and dominated by C→T transitions at dipyrimidines, namely UV-signature mutations. However, sequence preferences of the occurrence of UV-signature mutations were quite different between the two genotypes: the mutations occurred at a higher frequency preferentially at the 5'-TCG-3' sequence context than at the other dipyrimidine contexts in the Polh(+/+) epidermis, whereas the mutations were induced remarkably and exclusively at the 3'-cytosine of almost all dipyrimidine contexts with no preference for 5'-TCG-3' in the Polh(-/-) epidermis. In addition, in Polh(-/-) mice, a small but remarkable fraction of G→T transversions was also observed exclusively at the 3'-cytosine of dipyrimidine sites, strongly suggesting that these transversions resulted not from oxidative damage but from UV photolesions. These results would reflect the characteristics of the error-prone TLS functioning in the bypass of UV photolesions in the absence of polη, which would be mediated by mechanisms based on the two-step model of TLS. On the other hand, the deamination model would explain well the mutation

  13. A remarkable difference in CO2 hydrogenation to methanol on Pd nanoparticles supported inside and outside of carbon nanotubes.

    Wang, Jijie; Lu, Sheng-mei; Li, Jun; Li, Can


    An obvious difference was found in CO2 hydrogenation to methanol on Pd nanoparticles (NPs) supported inside and outside of carbon nanotubes (CNTs). The turnover frequency of methanol synthesis on the Pd NPs supported inside of CNTs was 3.7 times those supported outside of CNTs. It was found that the amount of Pd(δ+) species inside of CNTs was much higher than that outside of CNTs. We proposed that one of the major reasons for the difference in CO2 hydrogenation to methanol might be relative to the concentration of the Pd(δ+) species.

  14. Diastereoselective Desymmetrization of Symmetric Dienes and its Synthetic Application

    Kenji Nakahara


    Full Text Available The desymmetrization of symmetric compounds is a useful approach to obtain chiral building blocks. Readily available precursors with a prochiral unit could be converted into complex molecules with multiple stereogenic centers in a single step. In this review, recent advances in the desymmetrization of symmetric dienes in the diastereotopic group differentiating reaction and its synthetic application are presented.

  15. Chemo- and diastereoselectivities in the electrochemical reduction of maleimides.

    Rix, Kathryn; Kelsall, Geoffrey H; Hellgardt, Klaus; Hii, King Kuok Mimi


    The electrochemical cathodic reduction of cyclic imides (maleimides) to succinimides can be achieved chemoselectively in the presence of alkene, alkyne, and benzyl groups. The efficiency of the system was demonstrated by using a 3D electrode in a continuous flow reactor. The reduction of 3,4-dimethylmaleimides to the corresponding succinimides proceeds with a 3:2 diastereomeric ratio, which is independent of the nitrogen substituent and electrode surface area. The stereoselectivity of the process was rationalized by using DFT calculations, involving an acid-catalyzed tautomerization of a half-enol occurring through a double hydrogen-transfer mechanism. © 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  16. Approach to Monobactams and Nocardicins via Diastereoselective Kinugasa Reaction.

    Kabala, Kamil; Grzeszczyk, Barbara; Stecko, Sebastian; Furman, Bartłomiej; Chmielewski, Marek


    A Kinugasa reaction between copper(I) acetylides and cyclic nitrones derived from chiral amino alcohols and glyoxylic acid is reported. The stereochemical preferences observed in this reaction are discussed. The alkyne molecule approaches the nitrone exclusively anti to the large substituent next to the nitrogen atom to provide the cis-substituted β-lactam ring preferentially. The six-membered oxazinone ring can be opened by reduction with lithium borohydride. Deprotection of the β-lactam nitrogen atom can be achieved by lithium in liquid ammonia reduction or by CAN oxidation, depending on the substituents attached to the four-membered azetidinone ring. The adducts obtained by the Kinugasa reaction provide an attractive entry to a variety of monocyclic β-lactam structures related to monobactams and nocardicins.

  17. Remarkable swelling capability of amino acid based cross-linked polymer networks in organic and aqueous medium.

    Roy, Saswati Ghosh; Haldar, Ujjal; De, Priyadarsi


    This work reports design and synthesis of side chain amino acid based cross-linked polymeric gels, able to switch over from organogel to hydrogel by a simple deprotection reaction and showing superabsorbancy in water. Amino acid based methacrylate monomers, tert-butoxycarbonyl (Boc)-l/d-alanine methacryloyloxyethyl ester (Boc-l/d-Ala-HEMA), have been polymerized in the presence of a cross-linker via conventional free radical polymerization (FRP) and the reversible addition-fragmentation chain transfer (RAFT) technique for the synthesis of cross-linked polymer gels. The swelling behaviors of these organogels are investigated in organic solvents, and they behave as superabsorbent materials for organic solvents such as dichloromethane, acetone, tetrahydrofuran, etc. Swollen cross-linked polymer gels release the absorbed organic solvent rapidly. After Boc group deprotection from the pendant alanine moiety, the organogels transform to the hydrogels due to the formation of side chain ammonium (-NH3(+)) groups, and these hydrogels showed a significantly high swelling ratio (∼560 times than their dry volumes) in water. The morphology of organogels and hydrogels is studied by field emission scanning electron microscopy (FE-SEM). Amino acid based cross-linked gels could find applications as absorbents for oil spilled on water as well as superabsorbent hydrogels.

  18. Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

    Dolmatov, Valerii Yu [Federal State Unitary Enterprise Special Design-Technology Bureau (FSUE SDTB) ' ' Tekhnolog' ' at the St Petersburg State Institute of Technology (Technical University) (Russian Federation)


    The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

  19. Prodigious Effects of Concentration Intensification on Nanoparticle Synthesis: A High-Quality, Scalable Approach.

    Williamson, Curtis B; Nevers, Douglas R; Hanrath, Tobias; Robinson, Richard D


    Realizing the promise of nanoparticle-based technologies demands more efficient, robust synthesis methods (i.e., process intensification) that consistently produce large quantities of high-quality nanoparticles (NPs). We explored NP synthesis via the heat-up method in a regime of previously unexplored high concentrations near the solubility limit of the precursors. We discovered that in this highly concentrated and viscous regime the NP synthesis parameters are less sensitive to experimental variability and thereby provide a robust, scalable, and size-focusing NP synthesis. Specifically, we synthesize high-quality metal sulfide NPs (200 g) relative to the current field of large-scale (0.1-5 g yields) and laboratory-scale (<0.1 g) efforts. Compared to conventional synthesis methods (hot injection with dilute precursor concentration) characterized by rapid growth and low yield, our highly concentrated NP system supplies remarkably controlled growth rates and a 10-fold increase in NP volumetric production capacity (86 g/L). The controlled growth, high yield, and robust nature of highly concentrated solutions can facilitate large-scale nanomanufacturing of NPs by relaxing the synthesis requirements to achieve monodisperse products. Mechanistically, our investigation of the thermal and rheological properties and growth rates reveals that this high concentration regime has reduced mass diffusion (a 5-fold increase in solution viscosity), is stable to thermal perturbations (∼64% increase in heat capacity), and is resistant to Ostwald ripening.

  20. Behavioral synthesis of asynchronous circuits

    Nielsen, Sune Fallgaard


    This thesis presents a method for behavioral synthesis of asynchronous circuits, which aims at providing a synthesis flow which uses and tranfers methods from synchronous circuits to asynchronous circuits. We move the synchronous behavioral synthesis abstraction into the asynchronous handshake...... is idle. This reduces unnecessary switching activity in the individual functional units and therefore the energy consumption of the entire circuit. A collection of behavioral synthesis algorithms have been developed allowing the designer to perform time and power constrained design space exploration...

  1. (5aR)-5a-C-Pentyl-4-epi-isofagomine: A powerful inhibitor of lysosomal β-galactosidase and a remarkable chaperone for mutations associated with GM1-gangliosidosis and Morquio disease type B.

    Front, Sophie; Biela-Banaś, Anna; Burda, Patricie; Ballhausen, Diana; Higaki, Katsumi; Caciotti, Anna; Morrone, Amelia; Charollais-Thoenig, Julie; Gallienne, Estelle; Demotz, Stéphane; Martin, Olivier R


    This report is about the identification, synthesis and initial biological characterization of derivatives of 4-epi-isofagomine as pharmacological chaperones (PC) for human lysosomal β-galactosidase. The two epimers of 4-epi-isofagomine carrying a pentyl group at C-5a, namely (5aR)- and (5aS)-5a-C-pentyl-4-epi-isofagomine, were prepared by an innovative procedure involving in the key step the addition of nitrohexane to a keto-pentopyranoside. Both epimers were evaluated as inhibitors of the human β-galactosidase: the (5aR)-stereoisomer (compound 1) was found to be a very potent inhibitor of the enzyme (IC50 = 8 nM, 30× more potent than 4-epi-isofagomine at pH 7.3) with a high selectivity for this glycosidase whereas the (5aS) epimer was a much weaker inhibitor. In addition, compound 1 showed a remarkable activity as a PC. It significantly enhanced the residual activity of mutant β-galactosidase in 15 patient cell lines out of 23, with enhancement factors greater than 3.5 in 10 cell lines and activity restoration up to 91% of normal. Altogether, these results indicated that (5aR)-5a-C-pentyl-4-epi-isofagomine constitutes a promising PC-based drug candidate for the treatment of GM1-gangliosidosis and Morquio disease type B.

  2. Dissulfeto de molibdênio, um material multifuncional e surpreendente Molybdenum disulfide, a multifunctional and remarkable material

    Fernando Wypych


    Full Text Available The aim of this work is to review the chemical and physical properties of layered molybdenum disulfide. The three polymorphic/polytypic modifications of the compound were found, the polytypes 2H (molybdenite and 3R are semiconductors while the polymorph 1T is an electronic conductor. 2H-MoS2 has several important industrial applications as hydrotreatment catalysts, energy storage devices, solar cells, solid lubricants, among others. When intercalated, the 2H phase changes to a distorted 1T phase, producing unstable intercalation compounds that can be exfoliated in solution, producing single layers and consequently nanocomposites. The direct synthesis of the 1T phase produces stable intercalation compounds. Recently molybdenum disulfide was prepared as nanotubes and fulerene-like structures that bring new insights in the investigation of this important material.

  3. Acute inactivation of the replicative helicase in human cells triggers MCM8-9-dependent DNA synthesis

    Natsume, Toyoaki; Nishimura, Kohei; Minocherhomji, Sheroy


    (DSBs). Remarkably, these cells maintain some DNA synthesis in the absence of MCM2, and this requires the MCM8-9 complex, a paralog of the MCM2-7 replicative helicase. We show that MCM8-9 functions in a homologous recombination-based pathway downstream from RAD51, which is promoted by DSB induction....... This RAD51/MCM8-9 axis is distinct from the recently described RAD52-dependent DNA synthesis pathway that operates in early mitosis at common fragile sites. We propose that stalled replication forks can be restarted in S phase via homologous recombination using MCM8-9 as an alternative replicative helicase....

  4. Pushing the limits - two new species of Pteromalus (Hymenoptera, Chalcidoidea, Pteromalidae) from Central Europe with remarkable morphology.

    Baur, Hannes


    Two new species, Pteromalusbriani sp. n. and Pteromalusjanstai sp. n., with unusual characters are described from the Central Plateau and the Alps in Switzerland, respectively. Pteromalusbriani sp. n. is remarkable in that it has the metatibia quite abruptly expanded before the middle. This type of modification of the hind tibia is unique within the Pteromalidae and probably also the entire Chalcidoidea. It is also very rare in other parasitic wasps, where it is suspected to be associated with pheromone glands. The species is a gregarious endoparasitoid of pupae of Vanessaatalanta (Linnaeus) and Aglaisurticae (Linnaeus), two common butterflies (Lepidoptera: Nymphalidae) in Europe. It is furthermore a koinobiont parasitoid ovipositing in an early larval stage of the host. The other species, Pteromalusjanstai sp. n., shows a flattened mesosoma. A dorsoventrally depressed body is a unique feature within the genus Pteromalus, but known from a number species in unrelated genera and subfamilies. The two records demonstrate that it is possible to discover entirely new species with extraordinary characters even in one of the taxonomically most thoroughly explored parts of the world.

  5. Pushing the limits – two new species of Pteromalus (Hymenoptera, Chalcidoidea, Pteromalidae) from Central Europe with remarkable morphology

    Baur, Hannes


    Abstract Two new species, Pteromalus briani sp. n. and Pteromalus janstai sp. n., with unusual characters are described from the Central Plateau and the Alps in Switzerland, respectively. Pteromalus briani sp. n. is remarkable in that it has the metatibia quite abruptly expanded before the middle. This type of modification of the hind tibia is unique within the Pteromalidae and probably also the entire Chalcidoidea. It is also very rare in other parasitic wasps, where it is suspected to be associated with pheromone glands. The species is a gregarious endoparasitoid of pupae of Vanessa atalanta (Linnaeus) and Aglais urticae (Linnaeus), two common butterflies (Lepidoptera: Nymphalidae) in Europe. It is furthermore a koinobiont parasitoid ovipositing in an early larval stage of the host. The other species, Pteromalus janstai sp. n., shows a flattened mesosoma. A dorsoventrally depressed body is a unique feature within the genus Pteromalus, but known from a number species in unrelated genera and subfamilies. The two records demonstrate that it is possible to discover entirely new species with extraordinary characters even in one of the taxonomically most thoroughly explored parts of the world. PMID:26261432

  6. Novel VEGF decoy receptor fusion protein conbercept targeting multiple VEGF isoforms provide remarkable anti-angiogenesis effect in vivo.

    Qin Wang

    Full Text Available VEGF family factors are known to be the principal stimulators of abnormal angiogenesis, which play a fundamental role in tumor and various ocular diseases. Inhibition of VEGF is widely applied in antiangiogenic therapy. Conbercept is a novel decoy receptor protein constructed by fusing VEGF receptor 1 and VEGF receptor 2 extracellular domains with the Fc region of human immunoglobulin. In this study, we systematically evaluated the binding affinity of conbercept with VEGF isoforms and PlGF by using anti-VEGF antibody (Avastin as reference. BIACORE and ELISA assay results indicated that conbercept could bind different VEGF-A isoforms with higher affinity than reference. Furthermore, conbercept could also bind VEGF-B and PlGF, whereas Avastin showed no binding. Oxygen-induced retinopathy model showed that conbercept could inhibit the formation of neovasularizations. In tumor-bearing nude mice, conbercept could also suppress tumor growth very effectively in vivo. Overall, our study have demonstrated that conbercept could bind with high affinity to multiple VEGF isoforms and consequently provide remarkable anti-angiogenic effect, suggesting the possibility to treat angiogenesis-related diseases such as cancer and wet AMD etc.

  7. The Pinnotheridae of the northeastern Pacific (Alaska to Mexico): zoogeographical remarks and new bivalve hosts (Crustacea, Brachyura, Pinnotheridae).

    Campos, Ernesto


    New bivalve host records for four pinnotherid crabs of the Mexican Pacific are reported: Fabia subquadrata Dana, 1851, in Modiolus capax (Conrad, 1837); Opisthopus transversus Rathbun, 1893, in Tivela stultorum (Mawe, 1823); Pinnaxodes gigas (Green, 1992), in Pinna rugosa (Sowerby, 1835), and Panopea generosa Gould, 1850; and Tumidotheres margarita (Smith, 1870), in Nodipecten subnodosus (Sowerby, 1835). The southernmost distribution of F. subquadrata is extended to about 600 km along the west coast of the Baja California Peninsula; the distribution of P. gigas is extended outside the Gulf of California more than 1000 km north to San Quintín, on the west coast of Baja California; and the range of T. margarita is restricted on the west coast of Baja California to Scammon´s Lagoon, Baja California Sur and Playa Kino Viejo, Sonora in the central region of the Gulf of California, Mexico to Panama. Based on the new material, new information on taxonomy, ecology, and life history is provided for each of these species. Pinnotheres nudus Holmes, 1895 is restored as a valid species and is removed from its synonymy with O. transversus. An updated checklist with remarks on zoogeography for the 60 pinnotherid species, included in 23 genera, of the northeastern Pacific region (Alaska to the Mexican tropical Pacific) is given.

  8. Remarkable reduction in the threshold voltage of pentacene-based thin film transistors with pentacene/CuPc sandwich configuration

    Yi Li


    Full Text Available This study investigates the remarkable reduction in the threshold voltage (VT of pentacene-based thin film transistors with pentacene/copper phthalocyanine (CuPc sandwich configuration. This reduction is accompanied by increased mobility and lowered sub-threshold slope (S. Sandwich devices coated with a 5 nm layer of CuPc layer are compared with conventional top-contact devices, and results indicate that VT decreased significantly from −20.4 V to −0.2 V, that mobility increased from 0.18 cm2/Vs to 0.51 cm2/Vs, and that S was reduced from 4.1 V/dec to 2.9 V/dec. However, the on/off current ratio remains at 105. This enhanced performance could be attributed to the reduction in charge trap density by the incorporated CuPc layer. Results suggest that this method is simple and effectively generates pentacene-based organic thin film transistors with high mobility and low VT.

  9. Remarkable changes in behavior and physiology of laboratory mice after the massive 2011 Tohoku earthquake in Japan.

    Yanai, Shuichi; Semba, Yuki; Endo, Shogo


    A devastating earthquake and tsunami hit Japan on March 11, 2011, followed by several long and intense aftershocks. Laboratory mice housed in the Tokyo, located approximately 330 km south of this earthquake's epicenter, displayed remarkable changes in a variety of behaviors and physiological measures. Although unusual pre-earthquake behaviors have been previously reported in laboratory animals, little is known about behavioral and physiological changes that occur after a great earthquake. In the present study, the effects of Tohoku earthquake on mice behavior were investigated. "Earthquake-experienced" mice displayed a marked increase in food consumption without gaining body weight in response to the earthquake. They also displayed enhanced anxiety, and in a formal fear memory task, showed significantly greater tone- and context-dependent conditioned freezing. Water maze performance of earthquake-experienced mice showed the quicker acquisition of the task, faster swim speed and longer swim distance than the naive mice. Serum corticosterone levels were elevated compared to the naive mice, indicating that the earthquake and aftershocks were stressful for the mice. These results demonstrate that great earthquakes strongly affect mouse behaviors and physiology. Although the effects of a variety of experimental manipulations on mouse behaviors in disease models or in models of higher cognitive functions have been extensively examined, researchers need to be aware how natural phenomena, such as earthquakes and perhaps other natural environmental factors, influence laboratory animal behaviors and physiology.

  10. A remarkable recurrent nova in M31: Discovery and optical/UV observations of the predicted 2014 eruption

    Darnley, M J; Steele, I A; Bode, M F; Ribeiro, V A R M; Rodríguez-Gil, P; Shafter, A W; Williams, S C; Baer, D; Hachisu, I; Hernanz, M; Hornoch, K; Hounsell, R; Kato, M; Kiyota, S; Kučáková, H; Maehara, H; Ness, J -U; Piascik, A S; Sala, G; Skillen, I; Smith, R J; Wolf, M


    The Andromeda Galaxy recurrent nova M31N 2008-12a had been caught in eruption eight times. The inter-eruption period of M31N 2008-12a is ~1 year, making it the most rapidly recurring system known, and a strong single-degenerate Type Ia Supernova progenitor candidate. Following the 2013 eruption, a campaign was initiated to detect the predicted 2014 eruption and to then perform high cadence optical photometric and spectroscopic monitoring using ground-based telescopes, along with rapid UV and X-ray follow-up with the Swift satellite. Here we report the results of a high cadence multicolour optical monitoring campaign, the spectroscopic evolution, and the UV photometry. We also discuss tantalising evidence of a potentially related, vastly-extended, nebulosity. The 2014 eruption was discovered, before optical maximum, on October 2, 2014. We find that the optical properties of M31N 2008-12a evolve faster than all Galactic recurrent novae known, and all its eruptions show remarkable similarity both photometrically...

  11. Locking covalent organic frameworks with hydrogen bonds: general and remarkable effects on crystalline structure, physical properties, and photochemical activity.

    Chen, Xiong; Addicoat, Matthew; Jin, Enquan; Zhai, Lipeng; Xu, Hong; Huang, Ning; Guo, Zhaoqi; Liu, Lili; Irle, Stephan; Jiang, Donglin


    A series of two-dimensional covalent organic frameworks (2D COFs) locked with intralayer hydrogen-bonding (H-bonding) interactions were synthesized. The H-bonding interaction sites were located on the edge units of the imine-linked tetragonal porphyrin COFs, and the contents of the H-bonding sites in the COFs were synthetically tuned using a three-component condensation system. The intralayer H-bonding interactions suppress the torsion of the edge units and lock the tetragonal sheets in a planar conformation. This planarization enhances the interlayer interactions and triggers extended π-cloud delocalization over the 2D sheets. Upon AA stacking, the resulting COFs with layered 2D sheets amplify these effects and strongly affect the physical properties of the material, including improving their crystallinity, enhancing their porosity, increasing their light-harvesting capability, reducing their band gap, and enhancing their photocatalytic activity toward the generation of singlet oxygen. These remarkable effects on the structure and properties of the material were observed for both freebase and metalloporphyin COFs. These results imply that exploration of supramolecular ensembles would open a new approach to the structural and functional design of COFs.

  12. [Remarks about the position of the medico-legal expert in imperative regulations in the Penal and Civil Codes].

    Chowaniec, Czesław; Nowak, Agnieszka; Chowaniec, Małgorzata; Kobek, Mariusz


    In the monograph 'Medico-legal opinions--essays on theory', prof. K. Jaegermann wrote that 'the use of an expert requires theoretical or fairly clear knowledge about the mutual relationship between judge and expert'. In his opinion knowledge of this kind plays a significant role in estimating the usefulness of so-called expert evidence. Practical knowledge about the relationship between the judge and expert is necessary but not a decisive condition not only for a lawyer to be a judge but also for a physician to be a medico-legal expert. An expert can be not only a person appointed by the court but must also possess proper knowledge in a particular field, namely, the required professional and specialist qualifications and must also considered to be impartial. On the basis of the analysis of law in force and imperative regulations in Penal and Civil Codes, the authors have presented remarks relating to the expert's status as well as the lack of judicial control over the activity of experts appointed by court. Verification of professional qualifications in court experts and a reduction of those appointed 'ad hoc' are suggested. In the authors opinion co-operation between lawyers and experts should be improved. It is also essential to introduce statutory legal protection of court experts as well as to undertake activities leading to equaling the status of Polish court experts to that of other European countries.

  13. Remarkable changes in behavior and physiology of laboratory mice after the massive 2011 Tohoku earthquake in Japan.

    Shuichi Yanai

    Full Text Available A devastating earthquake and tsunami hit Japan on March 11, 2011, followed by several long and intense aftershocks. Laboratory mice housed in the Tokyo, located approximately 330 km south of this earthquake's epicenter, displayed remarkable changes in a variety of behaviors and physiological measures. Although unusual pre-earthquake behaviors have been previously reported in laboratory animals, little is known about behavioral and physiological changes that occur after a great earthquake. In the present study, the effects of Tohoku earthquake on mice behavior were investigated. "Earthquake-experienced" mice displayed a marked increase in food consumption without gaining body weight in response to the earthquake. They also displayed enhanced anxiety, and in a formal fear memory task, showed significantly greater tone- and context-dependent conditioned freezing. Water maze performance of earthquake-experienced mice showed the quicker acquisition of the task, faster swim speed and longer swim distance than the naive mice. Serum corticosterone levels were elevated compared to the naive mice, indicating that the earthquake and aftershocks were stressful for the mice. These results demonstrate that great earthquakes strongly affect mouse behaviors and physiology. Although the effects of a variety of experimental manipulations on mouse behaviors in disease models or in models of higher cognitive functions have been extensively examined, researchers need to be aware how natural phenomena, such as earthquakes and perhaps other natural environmental factors, influence laboratory animal behaviors and physiology.

  14. Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas

    Roberta Gomes Carvalho/


    Full Text Available The geographical distribution of Aedes albopictus in Brazil was updated according to the data recorded across the country over the last eight years. Countrywide house indexes (HI for Ae. albopictus in urban and suburban areas were described for the first time using a sample of Brazilian municipalities. This mosquito is currently present in at least 59% of the Brazilian municipalities and in 24 of the 27 federal units (i.e., 26 states and the Federal District. In 34 Brazilian municipalities, the HI values for Ae. albopictus were higher than those recorded for Ae. aegypti, reaching figures as high as HI = 7.72 in the Southeast Region. Remarks regarding the current range of this mosquito species in the Americas are also presented. Nineteen American countries are currently infested and few mainland American countries have not confirmed the occurrence of Ae. albopictus. The large distribution and high frequency of Ae. albopictus in the Americas may become a critical factor in the spread of arboviruses like chikungunya in the new world.

  15. A brief history of the most remarkable numbers e, i and γ in mathematical sciences with applications

    Debnath, Lokenath


    This paper deals with a brief history of the most remarkable Euler numbers e, i and γ in mathematical sciences. Included are many properties of the constants e, i and γ and their applications in algebra, geometry, physics, chemistry, ecology, business and industry. Special attention is given to the growth and decay phenomena in many real-world problems including stability and instability of their solutions. Some specific and modern applications of logarithms, complex numbers and complex exponential functions to electrical circuits and mechanical systems are presented with examples. Included are the use of complex numbers and complex functions in the description and analysis of chaos and fractals with the aid of modern computer technology. In addition, the phasor method is described with examples of applications in engineering science. The major focus of this paper is to provide basic information through historical approach to mathematics teaching and learning of the fundamental knowledge and skills required for students and teachers at all levels so that they can understand the concepts of mathematics, and mathematics education in science and technology.

  16. Remarkable Changes in Behavior and Physiology of Laboratory Mice after the Massive 2011 Tohoku Earthquake in Japan

    Yanai, Shuichi; Semba, Yuki; Endo, Shogo


    A devastating earthquake and tsunami hit Japan on March 11, 2011, followed by several long and intense aftershocks. Laboratory mice housed in the Tokyo, located approximately 330 km south of this earthquake’s epicenter, displayed remarkable changes in a variety of behaviors and physiological measures. Although unusual pre-earthquake behaviors have been previously reported in laboratory animals, little is known about behavioral and physiological changes that occur after a great earthquake. In the present study, the effects of Tohoku earthquake on mice behavior were investigated. “Earthquake-experienced” mice displayed a marked increase in food consumption without gaining body weight in response to the earthquake. They also displayed enhanced anxiety, and in a formal fear memory task, showed significantly greater tone- and context-dependent conditioned freezing. Water maze performance of earthquake-experienced mice showed the quicker acquisition of the task, faster swim speed and longer swim distance than the naive mice. Serum corticosterone levels were elevated compared to the naive mice, indicating that the earthquake and aftershocks were stressful for the mice. These results demonstrate that great earthquakes strongly affect mouse behaviors and physiology. Although the effects of a variety of experimental manipulations on mouse behaviors in disease models or in models of higher cognitive functions have been extensively examined, researchers need to be aware how natural phenomena, such as earthquakes and perhaps other natural environmental factors, influence laboratory animal behaviors and physiology. PMID:22957073

  17. [A case of chronic inorganic mercury poisoning with progressive intentional tremor and remarkably prolonged latency of P300].

    Shikata, E; Mochizuki, Y; Oishi, M; Takasu, T


    A 59-year-old man showed slowly progressive intentional tremor for 40 years prior to first visit to us in 1996. He was exposed to mercury vapor for about 3 years (1956-1959) and the diagnosis of chronic inorganic mercury poisoning was made. Hasegawa dementia scale-revised (HDS-R), mini-mental state (MMS) examination and P300 examination were performed. HDS-R and MMS were within normal range but the latency of P300 was remarkably prolonged. His tremor was considered to be due to chronic inorganic poisoning because there were no other causes and the frequency of his tremor was 3-4 Hz. which was lower than that in essential tremor. The prolonged P300 latency was also considered to be due to the same cause because there were no other causes and the head MRI were normal. Chronic inorganic mercury poisoning has been reported to produce organic changes in the brain and P300 is considered to be useful to detect these changes.

  18. Remarkable Impact of Acidic Ginsenosides and Organic Acids on Ginsenoside Transformation from Fresh Ginseng to Red Ginseng.

    Liu, Zhi; Xia, Juan; Wang, Chong-Zhi; Zhang, Jin-Qiu; Ruan, Chang-Chun; Sun, Guang-Zhi; Yuan, Chun-Su


    Panax ginseng contains many chemical components, including acidic ginsenosides and organic acids. However, whether these acidic substances play a role in ginsenoside transformation during steaming treatment has not yet been explored. In this paper, the content of neutral ginsenosides, acidic ginsenosides, and their degradation products in unsteamed and steamed P. ginseng were simultaneously quantified by high-performance liquid chromatography. We observed that neutral ginsenosides were converted to rare ginsenosides during the root steaming but not during the individual ginsenoside steaming. In contrast, acidic malonyl ginsenosides released malonic acid and acetic acid through demalonylation, decarboxylation, deacetylation reactions during the steaming at 120 °C. These malonyl ginsenosides not only were converted to rare ginsenosides but also promoted the degradation of neutral ginsenosides. Further studies indicated that a low concentration of organic acid was the determining factor for the ginsenoside conversion. The related mechanisms were deduced to be mainly acidic hydrolysis and dehydration. In summary, acidic ginsenosides and organic acids remarkably affected ginsenoside transformation during the steaming process. Our results provide useful information for precisely understanding the ginsenoside conversion pathways and mechanisms underlying the steaming process.

  19. Eugenol--from the remote Maluku Islands to the international market place: a review of a remarkable and versatile molecule.

    Kamatou, Guy P; Vermaak, Ilze; Viljoen, Alvaro M


    Eugenol is a major volatile constituent of clove essential oil obtained through hydrodistillation of mainly Eugenia caryophyllata (=Syzygium aromaticum) buds and leaves. It is a remarkably versatile molecule incorporated as a functional ingredient in numerous products and has found application in the pharmaceutical, agricultural, fragrance, flavour, cosmetic and various other industries. Its vast range of pharmacological activities has been well-researched and includes antimicrobial, anti-inflammatory, analgesic, anti-oxidant and anticancer activities, amongst others. In addition, it is widely used in agricultural applications to protect foods from micro-organisms during storage, which might have an effect on human health, and as a pesticide and fumigant. As a functional ingredient, it is included in many dental preparations and it has also been shown to enhance skin permeation of various drugs. Eugenol is considered safe as a food additive but due to the wide range of different applications, extensive use and availability of clove oil, it is pertinent to discuss the general toxicity with special reference to contact dermatitis. This review summarises the pharmacological, agricultural and other applications of eugenol with specific emphasis on mechanism of action as well as toxicity data.

  20. Eugenol—From the Remote Maluku Islands to the International Market Place: A Review of a Remarkable and Versatile Molecule

    Alvaro M. Viljoen


    Full Text Available Eugenol is a major volatile constituent of clove essential oil obtained through hydrodistillation of mainly Eugenia caryophyllata (=Syzygium aromaticum buds and leaves. It is a remarkably versatile molecule incorporated as a functional ingredient in numerous products and has found application in the pharmaceutical, agricultural, fragrance, flavour, cosmetic and various other industries. Its vast range of pharmacological activities has been well-researched and includes antimicrobial, anti-inflammatory, analgesic, anti-oxidant and anticancer activities, amongst others. In addition, it is widely used in agricultural applications to protect foods from micro-organisms during storage, which might have an effect on human health, and as a pesticide and fumigant. As a functional ingredient, it is included in many dental preparations and it has also been shown to enhance skin permeation of various drugs. Eugenol is considered safe as a food additive but due to the wide range of different applications, extensive use and availability of clove oil, it is pertinent to discuss the general toxicity with special reference to contact dermatitis. This review summarises the pharmacological, agricultural and other applications of eugenol with specific emphasis on mechanism of action as well as toxicity data.