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Sample records for carbonyl cluster complexes

  1. Reactions of ruthenium and osmium cluster carbonyls with heteroatom-substituted and functionalized alkynes

    International Nuclear Information System (INIS)

    Koridze, A.A.

    2000-01-01

    The results of studies of the reactions of ruthenium and osmium cluster carbonyls with metal (M = Re, Mn, Fe) alkynes, silylalkynes, propargyl alcohols and their derivatives, diynes, enynes, and ferrocenylacetylene are summarized. Intramolecular rearrangements in the cluster complexes including migrations of carbonyl, hydride, and hydrocarbon ligands and the metal core reorganization are considered [ru

  2. Anchoring selenido-carbonyl ruthenium clusters to functionalized silica xerogels

    International Nuclear Information System (INIS)

    Cauzzi, Daniele; Graiff, Claudia; Pattacini, Roberto; Predieri, Giovanni; Tiripicchio, Antonio

    2003-01-01

    Silica Xerogels containing carbonyl Ru 3 Se 2 nido clusters were prepared in three different ways. The simple dispersion of [Ru 3 (μ 3 -Se) 2 (CO) 7 (PPh 3 ) 2 ] via sol gel process produces an inhomogeneous material; by contrast, homogeneous xerogels were obtained by reaction of [Ru 3 (μ 3 -Se) 2 (CO) 8 (PPh 3 )] with functionalized xerogels containing grafted diphenylphosphine moieties and by reaction of [Ru 3 (CO) 12 ] with a xerogel containing grafted phosphine-selenide groups. The reaction between [Ru 3 (CO) 12 ] and dodecyl diphenylphosphine selenide led to the formation of four selenido carbonyl clusters, which are soluble in hydrocarbon solvents and can be deposited as thin films from their solution by slow evaporation. (author)

  3. Carbonyl complexes of rhodium with N-donor ligands: factors determining the formation of terminal versus bridging carbonyls

    NARCIS (Netherlands)

    Dzik, W.I.; Creusen, C.; de Gelder, R.; Peters, T.P.J.; Smits, J.M.M.; de Bruin, B.

    2010-01-01

    Cationic rhodium carbonyl complexes supported by a series of different N-3- and N-4-donor ligands were prepared, and their ability to form carbonyl-bridged species was evaluated. Complex [Rh(K3-bpa)(cod)r (1(+)) (bpa = bis(2-picolyBamine, cod = cis,cis-1,5-cyclooctadiene) reacts with I bar of CO to

  4. Ammonia synthesis in the presence of rhodium-ruthenium-iridium carbonyl clusters

    International Nuclear Information System (INIS)

    Fedoseev, I.V.; Solov'ev, N.V.

    2007-01-01

    Researches in the field of platinum metal coordination compounds, where nitrogen enters as a ligand in coordination sphere of metal, are discussed. Results of experiments on the ammonia synthesis during the CO+N 2 mixture passing through alkali solution containing mixture of carbonyl clusters of rhodium, ruthenium and iridium at atmospheric pressure are given. Technique of the experiment and steps of assumed reactions of nitrogen fixation by Rh, Ir and Ru carbonyl clusters are demonstrated [ru

  5. A Moessbauer effect study of the bonding in several organoiron carbonyl clusters

    International Nuclear Information System (INIS)

    Long, G.J.; O'Brien, J.F.

    1988-01-01

    After a brief review of the applications of the Moessbauer effect to cyclopentadienyl containing compounds, the chemistry and spectral properties of the various iron carbonyl complexes are described. The electronic properties of a series of trinuclear and tetranuclear organoiron clusters have been investigated through Fenske-Hall self-consistent field molecular orbital calculations, and the results are compared with the Moessbauer effect isomer shifts. A linear correlation is found between the Slater effective nuclear charge, as calculated from the Fenske-Hall partial orbital occupancy factors, and the isomer shift. In these compounds the 4s orbital populations are rather constant. However, the cis and trans isomers of [CpFe(CO) 2 ] 2 have a significantly lower 4s orbital populations. In this case, the reduced 4s population must be accounted for by adding it to the effective nuclear charge to obtain a good correlation with the isomer shift. (orig.)

  6. Weak carbonyl-methyl intermolecular interactions in acetone clusters explored by IR plus VUV spectroscopy

    International Nuclear Information System (INIS)

    Guan, Jiwen; Hu, Yongjun; Xie, Min; Bernstein, Elliot R.

    2012-01-01

    Highlights: ► The carbonyl overtone of acetone clusters is observed by IR-VUV spectroscopy. ► Acetone molecules in the dimer are stacked with an antiparallel way. ► The structure of the acetone trimer and the tetramer are the cyclic structures. ► The carbonyl groups would interact with the methyl groups in acetone clusters. ► These weak interactions are further confirmed by H/D substitution experiment. -- Abstract: Size-selected IR–VUV spectroscopy is employed to detect vibrational characteristics in the region 2850 ∼ 3550 cm −1 of neutral acetone and its clusters (CH 3 COCH 3 ) n (n = 1–4). Features around 3440 cm −1 in the spectra of acetone monomer and its clusters are assigned to the carbonyl stretch (CO) overtone. These features red-shift from 3455 to 3433 cm −1 as the size of the clusters increases from the monomer to the tetramer. Based on calculations, the experimental IR spectra in the C=O overtone region suggest that the dominant structures for the acetone trimer and tetramer should be cyclic in the supersonic expansion sample. This study also suggests that the carbonyl groups interact with the methyl groups in the acetone clusters. These weak interactions are further confirmed by the use of deuterium substitution.

  7. Cyclometallated ruthenium(II) carbonyl complexes with 1 ...

    Indian Academy of Sciences (India)

    The characterization of the complexes having the ... Electronic spectra of the complexes display multiple strong absorptions in the ... Microanalyses (CHN) were performed by using a ..... proton.47,49 Absence of this signal in the spectra of.

  8. Reductive coupling of carbon monoxide in a rhenium carbonyl complex with pendant Lewis acids.

    Science.gov (United States)

    Miller, Alexander J M; Labinger, Jay A; Bercaw, John E

    2008-09-10

    Phosphinoborane ligands impart unique reactivity to a rhenium carbonyl cation relative to simple phosphine complexes. Addition of either triethylborohydride or a platinum hydride (that can be formed from H2) forms a rhenium boroxycarbene. This carbene, which crystallizes as a dimer, disproportionates over a period of days to afford the starting cation and a structurally unprecedented boroxy(boroxymethyl)carbene, in which a new C-C bond has been formed between two reduced CO ligands. This product of C-C bond formation can be independently synthesized by addition of 2 equiv of hydride to the rhenium carbonyl cation.

  9. Gas-phase chemistry of Mo, Ru, W, and Os metal carbonyl complexes

    International Nuclear Information System (INIS)

    Wang, Y.; Qin, Z.; Fan, F.L.

    2014-01-01

    Metal carbonyl complexes were used for studying the gas-phase chemical behavior of Mo, Ru, W and Os isotopes with an on-line low temperature isothermal gas chromatography apparatus. Short-lived Mo and Ru isotopes were produced by a 252 Cf spontaneous fission source. Short-lived nuclides of W and Os were produced using the heavy ion reactions 19 F + 159 Tb and 165 Ho, respectively. Short-lived products were thermalized in a recoil chamber filled with a gas mixture of helium and carbon monoxide. The carbonyls formed were then transported through capillaries to an isothermal chromatography column for study of the adsorption behavior as a function of temperature. On-line isothermal chromatography (IC) experiments on Teflon (PTFE) and quartz surfaces showed that short-lived isotopes of the listed elements can form carbonyl complexes which are very volatile and interact most likely in physical sorption processes. Deduced adsorption enthalpies of Mo and Ru carbonyls were -38 ± 2 kJ/mol and -36 ± 2 kJ/mol, respectively. These values are in good agreement with literature data, partly obtained with different chromatographic techniques. A validation of the applied Monte Carlo model to deduce adsorption enthalpies with Mo isotopes of different half-lives proved the validity of the underlying adsorption model. The investigations using a gas-jet system coupled to a heavy ion accelerator without any preseparator clearly showed the limitations of the approach. The He and CO gas mixture, which was directly added into the chamber, will result in decomposition of CO gas and produce some aerosol particles. After the experiment of 173 W and 179 Os in the heavy ion experiments, the Teflon column was covered by a yellowish deposit; the adsorption enthalpy of W and Os carbonyls could therefore not be properly deduced using Monte Carlo simulations. (orig.)

  10. Reductive Coupling of Carbon Monoxide in a Rhenium Carbonyl Complex with Pendant Lewis Acids

    OpenAIRE

    Miller, Alexander J. M.; Labinger, Jay A.; Bercaw, John E.

    2008-01-01

    Phosphinoborane ligands impart unique reactivity to a rhenium carbonyl cation relative to simple phosphine complexes. Addition of either triethylborohydride or a platinum hydride (that can be formed from H2) forms a rhenium boroxycarbene. This carbene, which crystallizes as a dimer, disproportionates over a period of days to afford the starting cation and a structurally unprecedented boroxy(boroxymethyl)carbene, in which a new C−C bond has been formed between two reduced CO ligands. This prod...

  11. Gold cluster carbonyls: saturated adsorption of CO on gold cluster cations, vibrational spectroscopy, and implications for their structures.

    Science.gov (United States)

    Fielicke, André; von Helden, Gert; Meijer, Gerard; Pedersen, David B; Simard, Benoit; Rayner, David M

    2005-06-15

    We report on the interaction of carbon monoxide with cationic gold clusters in the gas phase. Successive adsorption of CO molecules on the Au(n)(+) clusters proceeds until a cluster size specific saturation coverage is reached. Structural information for the bare gold clusters is obtained by comparing the saturation stoichiometry with the number of available equivalent sites presented by candidate structures of Au(n)(+). Our findings are in agreement with the planar structures of the Au(n)(+) cluster cations with n < or = 7 that are suggested by ion mobility experiments [Gilb, S.; Weis, P.; Furche, F.; Ahlrichs, R.; Kappes, M. M. J. Chem. Phys. 2001, 116, 4094]. By inference we also establish the structure of the saturated Au(n)(CO)(m)(+) complexes. In certain cases we find evidence suggesting that successive adsorption of CO can distort the metal cluster framework. In addition, the vibrational spectra of the Au(n)(CO)(m)(+) complexes in both the CO stretching region and in the region of the Au-C stretch and the Au-C-O bend are measured using infrared photodepletion spectroscopy. The spectra further aid in the structure determination of Au(n)(+), provide information on the structure of the Au(n)(+)-CO complexes, and can be compared with spectra of CO adsorbates on deposited clusters or surfaces.

  12. Electrochemical synthesis of transition element complexes with carboxyl- and carbonyl-containing ligands

    International Nuclear Information System (INIS)

    Frolov, V.Yu.; Bolotin, S.N.; Panyushkin, V.T.

    2005-01-01

    Complexes of d- and f-elements (E = Cu, Ni, Zn, Nd, Tb, Pr, Gd, Er) with carboxyl- and carbonyl-containing ligands were synthesized by the electrochemical method. The products were characterized by elemental analysis, thermal gravimetric analysis and IR spectra. The influence exerted by a number of factors on the process course was studied. The dependence of the electro synthesis parameters on the composition of the forming compounds was established. A new method for anodic synthesis of these compounds was developed [ru

  13. Effect of pretreatment temperature on catalytic performance of the catalysts derived from cobalt carbonyl cluster in Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Byambasuren O

    2017-02-01

    Full Text Available The monometallic cobalt-based catalysts were prepared by pretreating the catalysts derived from carbonyl cluster precursor (CO6Co2CC(COOH2 supported on γ-Al2O3 with hydrogen at 180, 220, and 260°C respectively. The temperature effect of the pretreatments on the structure evolution of cluster precursors and the catalytic performance of the Fischer-Tropsch (F-T synthesis was investigated. The pretreated catalyst at 220°C with unique phase structure exhibited best catalytic activity and selectivity among three pretreated catalysts. Moreover, the catalysts exhibited high dispersion due to the formation of hydrogen bonds between the cluster precursor and γ-Al2O3 support.

  14. Diverse roles of hydrogen in rhenium carbonyl chemistry: hydrides, dihydrogen complexes, and a formyl derivative.

    Science.gov (United States)

    Li, Nan; Xie, Yaoming; King, R Bruce; Schaefer, Henry F

    2010-11-04

    Rhenium carbonyl hydride chemistry dates back to the 1959 synthesis of HRe(CO)₅ by Hieber and Braun. The binuclear H₂Re₂(CO)₈ was subsequently synthesized as a stable compound with a central Re₂(μ-H)₂ unit analogous to the B₂(μ-H)₂ unit in diborane. The complete series of HRe(CO)(n) (n = 5, 4, 3) and H₂Re₂(CO)(n) (n = 9, 8, 7, 6) derivatives have now been investigated by density functional theory. In contrast to the corresponding manganese derivatives, all of the triplet rhenium structures are found to lie at relatively high energies compared with the corresponding singlet structures consistent with the higher ligand field splitting of rhenium relative to manganese. The lowest energy HRe(CO)₅ structure is the expected octahedral structure. Low-energy structures for HRe(CO)(n) (n = 4, 3) are singlet structures derived from the octahedral HRe(CO)₅ structure by removal of one or two carbonyl groups. For H₂Re₂(CO)₉ a structure HRe₂(CO)₉(μ-H), with one terminal and one bridging hydrogen atom, lies within 3 kcal/mol of the structure Re₂(CO)₉(η²-H₂), similar to that of Re₂(CO)₁₀. For H₂Re₂(CO)(n) (n = 8, 7, 6) the only low-energy structures are doubly bridged singlet Re₂(μ-H)₂(CO)(n) structures. Higher energy dihydrogen complex structures are also found.

  15. Identification of the non-pertechnetate species in Hanford waste tanks, Tc(I) carbonyl complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lukens, Wayne W.; Shuh, David K.; Schroeder, Norman C.; Ashley, Kenneth R.

    2003-10-16

    Immobilization of the high-level nuclear waste stored at the Hanford Reservation has been complicated by the presence of soluble, lower-valent technetium species. Previous work by Schroeder and Blanchard has shown that these species cannot be removed by ion-exchange and are difficult to oxidize. The Tc-K edge XANES spectra of the species in Tanks SY-101 and SY-103 were reported by Blanchard, but they could not be assigned to any known technetium complex. We report that the XANES spectra are most likely those of Tc(I) carbonyl species, especially fac-Tc(CO){sub 3}(gluconate){sup 2-}. This is further supported by EXAFS and {sup 99}Tc-NMR studies in nonradioactive simulants of these tank wastes.

  16. Complex permeability and permittivity variation of carbonyl iron rubber in the frequency range of 2 to 18 GHz

    Directory of Open Access Journals (Sweden)

    Adriana Medeiros Gama

    2010-04-01

    Full Text Available The complex dielectric permittivity (e and magnetic permeability (m of Radar Absorbing Materials (RAM based on metallic magnetic particles (carbonyl iron particles embedded in a dielectric matrix (silicon rubber have been studied in the frequency range of 2 to 18 GHz. The relative permeability and permittivity of carbonyl iron-silicon composites for various mass fractions are measured by the transmission/reflection method using a vector network analyzer. The concentration dependence of permittivity and permeability on the frequency is analyzed. In a general way, the results show that e´ parameter shows a more significant variation among the evaluated parameters (e”, m”, m’. The comparison of dielectric and magnetic loss tangents (e”/e” and m”/m’, respectively shows more clearly the variation of both parameters (e and m according to the frequency. It is also observed that higher carbonyl iron content fractions favor both dielectric and magnetic loss tangents.

  17. Reactivity of Fe3(CO)12 with Alkynes R-C≡-C-R':Syntheses and Crystal Structures of Substituted Cyclic Ketones and Carbonyl Iron Complexes

    Institute of Scientific and Technical Information of China (English)

    SUO Quan-Ling; WU Le; SU Qian; ZHU Ning; GAO Yuan-Yuan; HONG Hai-Long; XIE Rui-Jun; HAN Li-Min

    2017-01-01

    The reactivity of carbonyl iron cluster with alkynes has been studied by the thermal reaction of Fe3(CO)12 with R-C≡C-R'(R =Fc (Ferrocenyl);R'=Ph (Phenyl),Fc,H).The hexacarbonyldiiron cluster with ferracyclopentadiene ring (μ2,η4-C4Ph4)Fe2(CO)6 (1) and one tetraphenyl substituted cyclopentadienone (Ph4C4CO) (2) were simultaneously obtained by the reaction of Fe3(CO)12 with alkyne (Ph-C≡C-Ph).Only one ferrole cluster (μ2,η4-C4Fc2H2)Fe2(CO)6 (3) was separated by using Fc-C≡C-H as alkyne.One tri-carbonyl iron complex (η4-C4Fc4CO)Fe(CO)3 (4) and an unexpected new cyclic ketone compound 2,2,4,5-tetraferrocenylcyclopenta-4-en-l,3-di-one [Fc4C3(CO)2] (5) were obtained by using Fc-C≡C-Fc as alkyne.A new complex (η4-2,4-diphenyl-3,5-diferrocenylcyclopenta-2,4-dien-l-one)-tricarbonyl iron (η4-C4Ph2Fc2CO)Fe(CO)3 (6)was synthesized by the reaction of Fe3(CO)12 with Fc-C≡C-Ph.The structures of compounds 1~6 were determined by X-ray single-crystal diffraction and spectroscopic characterization.The crystal structures of two new compounds 5 and 6 were analyzed.Our experimental results reveal the structural models of the reaction products are affected by the kinds of substituents from alkynes R-C≡C-R'.

  18. Femtosecond Fluorescence and Intersystem Crossing in Rhenium(I) Carbonyl-Bipyridine Complexes

    Czech Academy of Sciences Publication Activity Database

    Cannizzo, A.; Blanco-Rodríguez, A. M.; Nahhas, A. E.; Šebera, Jakub; Záliš, Stanislav; Vlček, Antonín; Chergui, M.

    2008-01-01

    Roč. 130, č. 28 (2008), s. 8967-8974 ISSN 0002-7863 R&D Projects: GA MŠk 1P05OC068 Institutional research plan: CEZ:AV0Z40400503 Keywords : rhenium(I) * carbonyl-bipyridine * intersystem crossing Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 8.091, year: 2008

  19. Synthesis and characterization of osmium carbonyl cluster compounds with molecular oxygen electroreduction capacity

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos, R.H.; Ocampo, A.L.; Moreira-Acosta, J.; Sebastian, P.J. [CIE-UNAM Solar Energy Laboratory, Morelos (Mexico). Photovoltaic Systems Group, Solar-Hydrogen-Fuel Cell

    2001-12-01

    A transition metal cluster electrocatalyst based on Os{sub x}(CO){sub n} was synthesized by pyrolysis of Os{sub 3} (CO){sub 12} in 1,2-Dichlorobenzene (b.p.{approx_equal}180{sup o}C) under inert atmosphere (N{sub 2}). The electrocatalytic parameters of the oxygen reduction reaction (ORR) for an Os{sub x}(CO){sub n} catalyst were studied with a rotating disk electrode in 0.5 MH{sub 2}SO{sub 4} electrolyte. The diffusion coefficient and solubility of O{sub 2} in 0.5 MH{sub 2}SO{sub 4} were calculated. Koutecky-Levich analysis of the linear voltamperometry data showed that the reaction follows first-order kinetics and the value of the Koutecky-Levich slope indicates a multielectron charge transfer during the ORR. The value of the Tafel slope obtained from the mass transfer corrected Tafel plots is 131 mV/decade. The performance of the catalyst in a H{sub 2}/O{sub 2} PEM fuel cell cathode was evaluated and found to be nearly as good as that of Pt. (author)

  20. Complex scaling in the cluster model

    International Nuclear Information System (INIS)

    Kruppa, A.T.; Lovas, R.G.; Gyarmati, B.

    1987-01-01

    To find the positions and widths of resonances, a complex scaling of the intercluster relative coordinate is introduced into the resonating-group model. In the generator-coordinate technique used to solve the resonating-group equation the complex scaling requires minor changes in the formulae and code. The finding of the resonances does not need any preliminary guess or explicit reference to any asymptotic prescription. The procedure is applied to the resonances in the relative motion of two ground-state α clusters in 8 Be, but is appropriate for any systems consisting of two clusters. (author) 23 refs.; 5 figs

  1. The complex lives of star clusters

    CERN Document Server

    Stevenson, David

    2015-01-01

    As with the author’s recent books Extreme Explosions and Under a Crimson Sun, the complex topic of star clusters is broken down and made accessible with clear links to other areas of astronomy in a language which the non-specialist can easily read and enjoy. The full range of a star cluster's lifespan is depicted, as both globular and open clusters are tracked from birth to eventual death. Why is it some are dense conglomerates of stars while others are looser associations? Are the young, brilliant clusters seen in neighboring galaxies such as the Large Magellanic Cloud, M33 or M82 analogous to the ancient globulars seen in the Milky Way? How will these clusters change as their stars wane and die? More interestingly, how does living in a dense star cluster affect the fates of the stars and any attendant planets that accompany them?   Star clusters form many of the most dazzling objects in the astronomers’ catalogs. Many amateur astronomers are interested in exploring how these objects are created and wh...

  2. Competitive cluster growth in complex networks.

    Science.gov (United States)

    Moreira, André A; Paula, Demétrius R; Costa Filho, Raimundo N; Andrade, José S

    2006-06-01

    In this work we propose an idealized model for competitive cluster growth in complex networks. Each cluster can be thought of as a fraction of a community that shares some common opinion. Our results show that the cluster size distribution depends on the particular choice for the topology of the network of contacts among the agents. As an application, we show that the cluster size distributions obtained when the growth process is performed on hierarchical networks, e.g., the Apollonian network, have a scaling form similar to what has been observed for the distribution of a number of votes in an electoral process. We suggest that this similarity may be due to the fact that social networks involved in the electoral process may also possess an underlining hierarchical structure.

  3. Highly efficient energy transfer from a carbonyl carotenoid to chlorophyll a in the main light harvesting complex of Chromera velia.

    Science.gov (United States)

    Durchan, Milan; Keşan, Gürkan; Slouf, Václav; Fuciman, Marcel; Staleva, Hristina; Tichý, Josef; Litvín, Radek; Bína, David; Vácha, František; Polívka, Tomáš

    2014-10-01

    We report on energy transfer pathways in the main light-harvesting complex of photosynthetic relative of apicomplexan parasites, Chromera velia. This complex, denoted CLH, belongs to the family of FCP proteins and contains chlorophyll (Chl) a, violaxanthin, and the so far unidentified carbonyl carotenoid related to isofucoxanthin. The overall carotenoid-to-Chl-a energy transfer exhibits efficiency over 90% which is the largest among the FCP-like proteins studied so far. Three spectroscopically different isofucoxanthin-like molecules were identified in CLH, each having slightly different energy transfer efficiency that increases from isofucoxanthin-like molecules absorbing in the blue part of the spectrum to those absorbing in the reddest part of spectrum. Part of the energy transfer from carotenoids proceeds via the ultrafast S2 channel of both the violaxanthin and isofucoxanthin-like carotenoid, but major energy transfer pathway proceeds via the S1/ICT state of the isofucoxanthin-like carotenoid. Two S1/ICT-mediated channels characterized by time constants of ~0.5 and ~4ps were found. For the isofucoxanthin-like carotenoid excited at 480nm the slower channel dominates, while those excited at 540nm employs predominantly the fast 0.5ps channel. Comparing these data with the excited-state properties of the isofucoxanthin-like carotenoid in solution we conclude that, contrary to other members of the FCP family employing carbonyl carotenoids, CLH complex suppresses the charge transfer character of the S1/ICT state of the isofucoxanthin-like carotenoid to achieve the high carotenoid-to-Chl-a energy transfer efficiency. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. (Pyridine)(tetrahydroborato)zinc complex, (Zn(BH4)2(py)), as a new stable, efficient and chemoselective reducing agent for reduction of carbonyl compounds

    International Nuclear Information System (INIS)

    Zeynizadeh, Behzad; Faraji, Fariba

    2003-01-01

    (Pyridine)(tetrahydroborato)zinc complex, (Zn(BH 4 ) 2 (py)), as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent

  5. (Pyridine)(tetrahydroborato)zinc complex, (Zn(BH{sub 4}){sub 2}(py)), as a new stable, efficient and chemoselective reducing agent for reduction of carbonyl compounds

    Energy Technology Data Exchange (ETDEWEB)

    Zeynizadeh, Behzad; Faraji, Fariba [Urima Univ., Urima (Iran, Islamic Republic of)

    2003-04-01

    (Pyridine)(tetrahydroborato)zinc complex, (Zn(BH{sub 4}){sub 2}(py)), as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, {alpha}-diketones and {alpha},{beta}-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent.

  6. Chalcogenhalide cluster rhenium- and molybdenum complexes

    International Nuclear Information System (INIS)

    Fedin, V.P.; Gubin, S.P.; Mishchenko, A.V.; Fedorov, V.E.

    1984-01-01

    The interaction of rhenium- and molybdenum chalcogenhalides with n-donor ligands (L) is studied. At heating Re 3 X 2 Hal 5 complexes up to 100 deg in DMSO in the L presence obtained are the complexes of the 1-6 composition Re 3 X 2 Hal 5 -x Lx DMSO (X=Se, Hal=Cl, L=Et 3 N(1); X=Se, Hal=Cl, L=Bipy(2); X=Se, Hal=Br, L=Et 3 N(3); X=Se, Hal=Br, L=Bipy(4); X=Te, Hal=Br, L=Et 3 N(5); X=Te, Hal=Br, L=(Me 2 NCH 2 ) 2 (6). In the course of boiling of Mo 3 S 7 Hal 4 with PPh 3 in MeCN the Mo 3 S 7 Hal 4 2PPh 3 complexes (Hal=Cl(7); Br(8)) are obtained. For 1 through 8 complexes the chemical analysis data and IR spectra are given. For 4 and 8 complexes the molecular mass is measured. A possible method of obtaining molecular trinuclear clusters from polymer clusters is discussed

  7. Study of electrocatalytic properties of iridium carbonyl cluster and rhodium carbonyl cluster compounds for the oxygen reduction and hydrogen oxidation reactions in 0.5 MH{sub 2}SO{sub 4} in presence and absence of methanol and carbon monoxide, respectively

    Energy Technology Data Exchange (ETDEWEB)

    Uribe-Godinez, J.; Borja-Arco, E.; Castellanos, R.H. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Escobedo (Mexico); Jimenez-Sandoval, O. [Centro de Investigacion y de Estudios Avanzados del Inst. Politecnico Nacional, Querataro (Mexico)

    2006-07-01

    The suitability of carbonyl cluster compounds as a substitute to platinum (Pt) in fuel cell catalysts was investigated. Iridium (Ir{sub 4}(CO){sub 12} and rhodium (Rh{sub 6}(CO){sub 116}) cluster compounds were investigated as potential new electrocatalysts for oxygen reduction reaction (ORR) in the presence and absence of methanol at different concentrations, as well as for the hydrogen oxidation reaction (HOR) with pure hydrogen and a hydrogen/carbon monoxide mixture. The materials were studied using room temperature rotating disk electrode (RDE) measurements and cyclic and linear sweep voltammetry techniques (LSV). Tafel slope and exchange current density were calculated using the LSV polarization curves. Cyclic voltamperometry results suggested that the electrocatalysts were tolerant to methanol. However, electrochemical behaviour of the materials altered in the presence of CO, and peaks corresponding to CO oxidation were observed in both cases. The rhodium carbonyl showed a higher current density for the ORR than the iridium carbonyl. The current potential curves in the presence of methanol were similar to those obtained without methanol. Results confirmed the tolerance properties of the materials to perform the ORR. Decreased current density values were observed during HOR, and were attributed to changes in the hydrogen solubility and diffusion coefficient due to the presence of CO. The Tafel slopes indicated that the mechanics of the HOR were Heyrovsky-Volmer. Results showed that the materials are capable of performing both ORR and HOR in an acid medium. It was noted that the iridium carbonyl cluster followed a 4-electron transfer mechanism towards the formation of water. It was concluded that the compounds are suitable for use as both cathodes and anodes in proton exchange membrane fuel cells (PEMFCs) and as cathodes in direct methanol fuel cells (DMFCs). 3 refs., 2 tabs., 3 figs.

  8. Carbonyl Activation by Borane Lewis Acid Complexation: Transition States of H2 Splitting at the Activated Carbonyl Carbon Atom in a Lewis Basic Solvent and the Proton-Transfer Dynamics of the Boroalkoxide Intermediate.

    Science.gov (United States)

    Heshmat, Mojgan; Privalov, Timofei

    2017-07-06

    By using transition-state (TS) calculations, we examined how Lewis acid (LA) complexation activates carbonyl compounds in the context of hydrogenation of carbonyl compounds by H 2 in Lewis basic (ethereal) solvents containing borane LAs of the type (C 6 F 5 ) 3 B. According to our calculations, LA complexation does not activate a ketone sufficiently enough for the direct addition of H 2 to the O=C unsaturated bond; but, calculations indicate a possibly facile heterolytic cleavage of H 2 at the activated and thus sufficiently Lewis acidic carbonyl carbon atom with the assistance of the Lewis basic solvent (i.e., 1,4-dioxane or THF). For the solvent-assisted H 2 splitting at the carbonyl carbon atom of (C 6 F 5 ) 3 B adducts with different ketones, a number of TSs are computed and the obtained results are related to insights from experiment. By using the Born-Oppenheimer molecular dynamics with the DFT for electronic structure calculations, the evolution of the (C 6 F 5 ) 3 B-alkoxide ionic intermediate and the proton transfer to the alkoxide oxygen atom were investigated. The results indicate a plausible hydrogenation mechanism with a LA, that is, (C 6 F 5 ) 3 B, as a catalyst, namely, 1) the step of H 2 cleavage that involves a Lewis basic solvent molecule plus the carbonyl carbon atom of thermodynamically stable and experimentally identifiable (C 6 F 5 ) 3 B-ketone adducts in which (C 6 F 5 ) 3 B is the "Lewis acid promoter", 2) the transfer of the solvent-bound proton to the oxygen atom of the (C 6 F 5 ) 3 B-alkoxide intermediate giving the (C 6 F 5 ) 3 B-alcohol adduct, and 3) the S N 2-style displacement of the alcohol by a ketone or a Lewis basic solvent molecule. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Microwave spectrum, dipole moment, and internal dynamics of the methyl fluoride-carbonyl sulfide weakly bound complex.

    Science.gov (United States)

    Serafin, Michal M; Peebles, Sean A

    2008-02-21

    Rotational spectra for the normal and four isotopically substituted species of the 1:1 complex between methyl fluoride (H3CF) and carbonyl sulfide (OCS) have been measured using Fourier-transform microwave spectroscopy in the 5-16 GHz frequency region. The observed spectra fit well to a semirigid Watson Hamiltonian, and an analysis of the rotational constants has allowed a structure to be determined for this complex. The dipole moment vectors of the H3CF and OCS monomers are aligned approximately antiparallel with a C...C separation of 3.75(3) A and with an ab plane of symmetry. The values of the Pcc planar moments were found to be considerably different from the expected rigid values for all isotopologues. An estimate of approximately 14.5(50) cm-1 for the internal rotation barrier of the CH3 group with respect to the framework of the complex has been made using the Pcc values for the H3CF-OCS and D3CF-OCS isotopic species. Two structures, very close in energy and approximately related by a 60 degrees rotation about the C3 axis of the methyl fluoride, were identified by ab initio calculations at the MP2/6-311++G(2d,2p) level and provide reasonable agreement with the experimental rotational constants and dipole moment components.

  10. Study of electron spectra of lanthanide complexes with carbonyl-containing reagents

    International Nuclear Information System (INIS)

    Tishchenko, M.A.; Gerasimenko, G.I.; Markina, A.I.; Tishchenko, V.V.; Rybalka, V.B.; Tsitko, A.S.

    1990-01-01

    Interaction of lanthanide complexes (Ln=Er, Nd, Ho) of 2-acetylindandione-1,3 with polyphenols was investigated by the methods of electron spectroscopy. Position, intensity, oscillator strengths of supersensitive transitions, formed in the system of different-ligand complexes were determined. 10 refs.; 4 figs.; 3 tabs

  11. THE SYNTHESIS OF BIOCONJUGATE BASED ON RHENIUM(I CARBONYL COMPLEX FOR VISUALIZATION OF PATHOLOGICAL PROCESS

    Directory of Open Access Journals (Sweden)

    K. O. Piletska

    2017-03-01

    Full Text Available Tricarbonyl rhenium(I complexes have a great potential like biomarkers. It is caused their biological stability, low toxicity, large Stokes shifts, and long luminescence lifetimes. Rhenium tricarbonyl complexes fac-[Re(CO3(N^N], where N^N is a ligand with low π* orbitals are excellent candidates as imaging dyes. The method of obtaining potential biomarkers based on tricarbonyl rhenium(I complex with a 4-methyl-2,2’-bipyridine-4’-carboxylate by the addition of biomolecules by peptide synthesis was developed. The new complex [Re(CO3MebpyCOOHBr] was synthesized, composition and structure of which were established by mass spectrometry, IR and NMR spectroscopy. A selective attachment of receptor peptide enkephalin to complex [Re(CO3(MebpyCOOHBr] was performed. The formation of a new compound and its structure has been confirmed by HPLC and mass spectral analysis. The method which has been developed allows to connect various peptides to rhenium(I complex in the solution.

  12. Preparations and characterization of some carbonyl-(1-cyanoethyl)ruthenium(II) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, Katsuma; Ochi, Naoyuki; Kitamura, Tsuneyuki; Sasada, Yoko [Nagasaki Univ. (Japan); Shinoda, Sumio

    1982-08-01

    A hydridoruthenium(II) complex (RuClH(CO)(PPh/sub 3/)/sub 3/) reacted easily with acrylonitrile and fumaronitrile to give chloro-bridged binuclear (1-cyanoethyl)ruthenium(II) complexes, ((Ru(MeCHCN)Cl(CO)(PPh/sub 3/)/sub 2/)/sub 2/) (2) and ((Ru(NCCH/sub 2/CHCN)Cl(CO)(PPh/sub 3/)/sub 2/)/sub 2/), respectively. Complex 2 reacted with 4-picoline (pic), Na(BHPz/sub 3/) (Pz = 1-pyrazolyl), Na(BPz/sub 4/), and Na(Et/sub 2/NCS/sub 2/).3H/sub 2/O to afford the corresponding (1-cyanoethyl)ruthenium(II) complexes, ((Ru(MeCHCN)Cl(CO)(pic)(PPh/sub 3/))/sub 2/) (3), (Ru(MeCHCN)(BHPz/sub 3/)(CO)(PPh/sub 3/)) (accompanied by a small amount of (Ru/sub 2/(MeCHCN)/sub 2/Cl(BHPz/sub 3/)(CO)/sub 2/(PPh/sub 3/)/sub 4/)), (Ru/sub 2/(MeCHCN)/sub 2/Cl(BPz/sub 4/)(CO)/sub 2/(PPh/sub 3/)/sub 2/), and Na(Ru(MeCHCN)Cl(Et/sub 2/NCS/sub 2/)(CO)(PPh/sub 3/)), respectively. Complex 3 reacted with thallium (I) acetylacetonate (Tl(acac)), resulting in the formation of ((Ru(MeCHCN)(acac)(CO)(PPh/sub 3/))/sub 2/) and (Ru(MeCHCN)(acad)(CO)(pic)(PPh/sub 3/)). These new complexes were characterized by means of elemental analysis and spectroscopic data. The diastereoisomerism was also discussed as regards these (1-cyanoethyl)ruthenium(II) complexes.

  13. Defects in tor regulatory complexes retard aging and carbonyl/oxidative stress development in yeast Sассharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    B. V. Homza

    2014-02-01

    Full Text Available TOR signaling pathway first described in yeast S. сerevisiae is the highly conserved regulator of eukaryotic cell growth, aging and stress resistance. The effect of nitrogen sources, in particular amino acids, on the activity of TOR signaling pathway is well studied, however its relation to carbohydrates is poor understood. The aim of the present study is expanding of our understanding of potential role of TOR regulatory complexes in development of carbonyl/oxidative stress that can result from yeast cultivation on glucose and fructose. It has been shown that the level of α-dicarbonyl compounds and protein carbonyl groups increased with time of yeast cultivation and was higher in cells grown on fructose that demonstrated their accelerated aging and carbonyl/oxidative stress development as compared with cells grown on glucose. The strains defective in TOR proteins cultivated in the presence of glucose as well as fructose demonstrated lower markers of the stress and aging than parental strain. Thus these data confirmed the previous conclusion on fructose more potent ability to cause carbonyl/oxidative stress and accelerated aging in S. cerevisiae as compared with glucose. However, defects in TOR regulatory complexes retard aging and development of the stress in yeast independent on the type of carbohydrate in the cultivation medium.

  14. Synthesis, structure and photoluminescence of novel lanthanide (Tb(III), Gd(III)) complexes with 6-diphenylamine carbonyl 2-pyridine carboxylate

    International Nuclear Information System (INIS)

    An Baoli; Gong Menglian; Cheah, Kok-Wai; Wong, Wai-Kwok; Zhang Jiming

    2004-01-01

    A novel organic ligand, 6-diphenylamine carbonyl 2-pyridine carboxylic acid (HDPAP), and the corresponding lanthanide complexes, tris(6-diphenylamine carbonyl 2-pyridine carboxylato) terbium(III) (Tb-DPAP) and tris(6-diphenylamine carbonyl 2-pyridine carboxylato) gadolinium(III) (Gd-DPAP) have been designed and synthesized. The crystal structure and photoluminescence of Tb-DPAP and Gd-DPAP have been studied. The results showed that the lanthanide complexes have electroneutral structures, and the solid terbium complex emits characteristic green fluorescence of Tb(III) ions at room temperature while the gadolinium complex emits the DPAP ligand phosphorescence. The lowest triplet level of DPAP ligand was calculated from the phosphorescence spectrum of Gd-DPAP in N,N-dimethyl formamide (DMF) dilute solution determined at 77 K, and the energy transfer mechanisms in the lanthanide complexes were discussed. The lifetimes of the 5 D 4 levels of Tb 3+ ions in the terbium complex were examined using time-resolved spectroscopy, and the values are 0.0153±0.0001 ms for solid Tb(DPAP) 3 ·11.5H 2 O and 0.074±0.007 ms for 2.5x10 -5 mol/l Tb-DPAP ethanol solution

  15. Fischer aminocarbene complexes of chromium and iron: Anomalous electrochemical reduction of p-carbonyl substituted derivatives

    Czech Academy of Sciences Publication Activity Database

    Hoskovcová, I.; Zvěřinová, R.; Roháčová, J.; Dvořák, D.; Tobrman, T.; Záliš, Stanislav; Ludvík, Jiří

    2011-01-01

    Roč. 56, č. 19 (2011), s. 6853-6859 ISSN 0013-4686 R&D Projects: GA AV ČR IAA400400813 Institutional research plan: CEZ:AV0Z40400503 Keywords : DFT calculations * electrochemistry * Fischer aminocarbene complexes Subject RIV: CG - Electrochemistry Impact factor: 3.832, year: 2011

  16. Preparation and bioevaluation of 99mTc-carbonyl complex of guanine

    International Nuclear Information System (INIS)

    Cigdem Ichedef; Serap Teksoez; Kamile Senocak; Eser Ucar; Ayfer Yurt Kilcar

    2011-01-01

    The aim of this study is to prepare radiolabeled guanine with 99m Tc(CO) 3 + core. For this purpose, guanine has been radiolabeled with 99m Tc(CO) 3 + core. Quality control study of radiolabeled guanine molecule with 99m Tc(CO) 3 + core was performed by thin layer radio chromatography (TLRC) and high performance liquid radio chromatography (HPLRC). The results showed that the radiolabeling yield was quite high (94 ± 3%). Beside that 99m Tc(CO) 3 -Gua complex has showed good in vitro stability during the 24 h period. Radiopharmaceutical potential of this complex was evaluated in Wistar Albino Rats. It was concluded that 99m Tc(CO) 3 -Gua could be used as a nucleotide radiopharmaceutical for in vivo applications. (author)

  17. Efficient light-harvesting using non-carbonyl carotenoids: Energy transfer dynamics in the VCP complex from Nannochloropsis oceanica.

    Science.gov (United States)

    Keşan, Gürkan; Litvín, Radek; Bína, David; Durchan, Milan; Šlouf, Václav; Polívka, Tomáš

    2016-04-01

    Violaxanthin-chlorophyll a protein (VCP) from Nannochloropsis oceanica is a Chl a-only member of the LHC family of light-harvesting proteins. VCP binds carotenoids violaxanthin (Vio), vaucheriaxanthin (Vau), and vaucheriaxanthin-ester (Vau-ester). Here we report on energy transfer pathways in the VCP complex. The overall carotenoid-to-Chla energy transfer has efficiency over 90%. Based on their energy transfer properties, the carotenoids in VCP can be divided into two groups; blue carotenoids with the lowest energy absorption band around 480nm and red carotenoids with absorption extended up to 530nm. Both carotenoid groups transfer energy efficiently from their S2 states, reaching efficiencies of ~70% (blue) and ~60% (red). The S1 pathway, however, is efficient only for the red carotenoid pool for which two S1 routes characterized by 0.33 and 2.4ps time constants were identified. For the blue carotenoids the S1-mediated pathway is represented only by a minor route likely involving a hot S1 state. The relaxed S1 state of blue carotenoids decays to the ground state within 21ps. Presence of a fraction of non-transferring red carotenoids with the S1 lifetime of 13ps indicates some specific carotenoid-protein interaction that must shorten the intrinsic S1 lifetime of Vio and/or Vau whose S1 lifetimes in methanol are 26 and 29ps, respectively. The VCP complex from N. oceanica is the first example of a light-harvesting complex binding only non-carbonyl carotenoids with carotenoid-to-chlorophyll energy transfer efficiency over 90%. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Lack of FTSH4 Protease Affects Protein Carbonylation, Mitochondrial Morphology, and Phospholipid Content in Mitochondria of Arabidopsis: New Insights into a Complex Interplay.

    Science.gov (United States)

    Smakowska, Elwira; Skibior-Blaszczyk, Renata; Czarna, Malgorzata; Kolodziejczak, Marta; Kwasniak-Owczarek, Malgorzata; Parys, Katarzyna; Funk, Christiane; Janska, Hanna

    2016-08-01

    FTSH4 is one of the inner membrane-embedded ATP-dependent metalloproteases in mitochondria of Arabidopsis (Arabidopsis thaliana). In mutants impaired to express FTSH4, carbonylated proteins accumulated and leaf morphology was altered when grown under a short-day photoperiod, at 22°C, and a long-day photoperiod, at 30°C. To provide better insight into the function of FTSH4, we compared the mitochondrial proteomes and oxyproteomes of two ftsh4 mutants and wild-type plants grown under conditions inducing the phenotypic alterations. Numerous proteins from various submitochondrial compartments were observed to be carbonylated in the ftsh4 mutants, indicating a widespread oxidative stress. One of the reasons for the accumulation of carbonylated proteins in ftsh4 was the limited ATP-dependent proteolytic capacity of ftsh4 mitochondria, arising from insufficient ATP amount, probably as a result of an impaired oxidative phosphorylation (OXPHOS), especially complex V. In ftsh4, we further observed giant, spherical mitochondria coexisting among normal ones. Both effects, the increased number of abnormal mitochondria and the decreased stability/activity of the OXPHOS complexes, were probably caused by the lower amount of the mitochondrial membrane phospholipid cardiolipin. We postulate that the reduced cardiolipin content in ftsh4 mitochondria leads to perturbations within the OXPHOS complexes, generating more reactive oxygen species and less ATP, and to the deregulation of mitochondrial dynamics, causing in consequence the accumulation of oxidative damage. © 2016 American Society of Plant Biologists. All Rights Reserved.

  19. Effects of Carbonyl Bond and Metal Cluster Dissociation and Evaporation Rates on Predictions of Nanotube Production in HiPco

    Science.gov (United States)

    Scott, Carl D.; Smalley, Richard E.

    2002-01-01

    The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon nanotubes (SWNT) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the co-formation of CO2. It is shown that the production of CO2 is significantly greater for FeCO due to its lower bond energy as compared with that ofNiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence.

  20. Solid-state thermolysis of a fac-rhenium(I) carbonyl complex with a redox non-innocent pincer ligand.

    Science.gov (United States)

    Jurca, Titel; Chen, Wen-Ching; Michel, Sheila; Korobkov, Ilia; Ong, Tiow-Gan; Richeson, Darrin S

    2013-03-25

    The development of rhenium(I) chemistry has been restricted by the limited structural and electronic variability of the common pseudo-octahedral products fac-[ReX(CO)3L2] (L2 = α-diimine). We address this constraint by first preparing the bidentate bis(imino)pyridine complexes [(2,6-{2,6-Me2C6H3N=CPh}2C5H3N)Re(CO)3X] (X = Cl 2, Br 3), which were characterized by spectroscopic and X-ray crystallographic means, and then converting these species into tridentate pincer ligand compounds, [(2,6-{2,6-Me2C6H3N=CPh}2C5H3N)Re(CO)2X] (X = Cl 4, Br 5). This transformation was performed in the solid-state by controlled heating of 2 or 3 above 200 °C in a tube furnace under a flow of nitrogen gas, giving excellent yields (≥95 %). Compounds 4 and 5 define a new coordination environment for rhenium(I) carbonyl chemistry where the metal center is supported by a planar, tridentate pincer-coordinated bis(imino)pyridine ligand. The basic photophysical features of these compounds show significant elaboration in both number and intensity of the d-π* transitions observed in the UV/Vis spec tra relative to the bidentate starting materials, and these spectra were analyzed using time-dependent DFT computations. The redox nature of the bis(imino)pyridine ligand in compounds 2 and 4 was examined by electrochemical analysis, which showed two ligand reduction events and demonstrated that the ligand reduction shifts to a more positive potential when going from bidentate 2 to tridentate 4 (+160 mV for the first reduction step and +90 mV for the second). These observations indicate an increase in electrostatic stabilization of the reduced ligand in the tridentate conformation. Elaboration on this synthetic methodology documented its generality through the preparation of the pseudo-octahedral rhenium(I) triflate complex [(2,6-{2,6-Me2C6H3N=CPh}2C5H3N)Re(CO)2OTf] (7, 93 % yield). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Highly efficient energy transfer from a carbonyl carotenoid to chlorophyll a in the main light harvesting complex of Chromera velia

    Czech Academy of Sciences Publication Activity Database

    Durchan, Milan; Kesan, G.; Šlouf, M.; Fuciman, M.; Staleva, H.; Tichý, Josef; Litvín, Radek; Bína, David; Vácha, František; Polívka, Tomáš

    2014-01-01

    Roč. 1837, č. 10 (2014), s. 1748-1755 ISSN 0005-2728 R&D Projects: GA ČR(CZ) GAP205/11/1164; GA ČR GBP501/12/G055 Institutional support: RVO:60077344 Keywords : Energy transfer * Light-harvesting * Carbonyl carotenoids Subject RIV: BO - Biophysics Impact factor: 5.353, year: 2014

  2. THE METAL CARBONYLS.

    Science.gov (United States)

    Blanchard, A A

    1941-10-03

    When the metal carbonyls were first discovered, their properties were startling because they seemed to violate nearly all the previously recognized generalizations of chemistry. Even to-day the existence of the carbonyls is not particularly emphasized in elementary courses of chemistry because it is rather hard to reconcile them with the first presentations of the generalizations of chemistry. Nevertheless, as the student progresses deeper into the knowledge of chemistry it becomes desirable to include the knowledge of the carbonyls both because they become more comprehensible when viewed in the light of Werner's system of coordination and because they themselves contribute to the comprehension of the Werner theory. As long ago as 1931, Reiff in his discussion of cobalt nitrosyl carbonyl recognized the correlation between the effective atomic number and the volatility of carbonyls. A more recent study of charged Werner coordination complexes, that is, of complex ions, has shown a similar role of the effective atomic number. We are standing on fairly firm ground when we point out the correlation between E.A.N. and the volatility of the carbonyl complexes and the existence of complex ions. Be it noted that we have made no postulates as to the arrangement of the electrons in quantum levels. In the inert gases the outer principal quantum group is supposed always to contain eight electrons. In the carbonyls and other Werner complexes there is no compelling reason to suppose that the electrons in the coordinating layer, be this layer of eight, ten, twelve or sixteen electrons, are not all at the same energy level. Although we have confined our discussion almost exclusively to the property of volatility, the carbonyls are very interesting from the standpoint of several other properties, for example, magnetic susceptibility and dielectric constant. Enthusiasts in the interpretation of such properties try to draw conclusions as to the condition of the electrons, sometimes

  3. Clustering biomolecular complexes by residue contacts similarity

    NARCIS (Netherlands)

    Garcia Lopes Maia Rodrigues, João; Trellet, Mikaël; Schmitz, Christophe; Kastritis, Panagiotis; Karaca, Ezgi; Melquiond, Adrien S J; Bonvin, Alexandre M J J; Garcia Lopes Maia Rodrigues, João

    Inaccuracies in computational molecular modeling methods are often counterweighed by brute-force generation of a plethora of putative solutions. These are then typically sieved via structural clustering based on similarity measures such as the root mean square deviation (RMSD) of atomic positions.

  4. Renewable Formate from C-H Bond Formation with CO2: Using Iron Carbonyl Clusters as Electrocatalysts.

    Science.gov (United States)

    Loewen, Natalia D; Neelakantan, Taruna V; Berben, Louise A

    2017-09-19

    As a society, we are heavily dependent on nonrenewable petroleum-derived fuels and chemical feedstocks. Rapid depletion of these resources and the increasingly evident negative effects of excess atmospheric CO 2 drive our efforts to discover ways of converting excess CO 2 into energy dense chemical fuels through selective C-H bond formation and using renewable energy sources to supply electrons. In this way, a carbon-neutral fuel economy might be realized. To develop a molecular or heterogeneous catalyst for C-H bond formation with CO 2 requires a fundamental understanding of how to generate metal hydrides that selectively donate H - to CO 2 , rather than recombining with H + to liberate H 2 . Our work with a unique series of water-soluble and -stable, low-valent iron electrocatalysts offers mechanistic and thermochemical insights into formate production from CO 2 . Of particular interest are the nitride- and carbide-containing clusters: [Fe 4 N(CO) 12 ] - and its derivatives and [Fe 4 C(CO) 12 ] 2- . In both aqueous and mixed solvent conditions, [Fe 4 N(CO) 12 ] - forms a reduced hydride intermediate, [H-Fe 4 N(CO) 12 ] - , through stepwise electron and proton transfers. This hydride selectively reacts with CO 2 and generates formate with >95% efficiency. The mechanism for this transformation is supported by crystallographic, cyclic voltammetry, and spectroelectrochemical (SEC) evidence. Furthermore, installation of a proton shuttle onto [Fe 4 N(CO) 12 ] - facilitates proton transfer to the active site, successfully intercepting the hydride intermediate before it reacts with CO 2 ; only H 2 is observed in this case. In contrast, isoelectronic [Fe 4 C(CO) 12 ] 2- features a concerted proton-electron transfer mechanism to form [H-Fe 4 C(CO) 12 ] 2- , which is selective for H 2 production even in the presence of CO 2 , in both aqueous and mixed solvent systems. Higher nuclearity clusters were also studied, and all are proton reduction electrocatalysts, but none

  5. Complex brain networks: From topological communities to clustered

    Indian Academy of Sciences (India)

    Complex brain networks: From topological communities to clustered dynamics ... Recent research has revealed a rich and complicated network topology in the cortical connectivity of mammalian brains. ... Pramana – Journal of Physics | News.

  6. Synthesis and characterization of bisoxazolines- and pybox-copper(II) complexes and their application in the coupling of α-carbonyls with functionalized amines

    KAUST Repository

    Jia, Weiguo

    2014-01-01

    Binuclear complexes [{(DMOX)CuCl}2(μ-Cl)2] (1), mononuclear complexes [(DMOX)CuBr2] (2) (DMOX = 4,5-dihydro-2-(4,5- dihydro-4,4-dimethyloxazol-2-yl)-4,4-dimethyloxazole) and the pybox Cu(ii) complex [(Dm-Pybox)CuBr2] (3) (Dm-Pybox = 2,6-bis[4′,4′- dimethyloxazolin-2′-yl]pyridine) were obtained by reactions of CuX 2 (X = Cl, Br) with DMOX and Dm-Pybox ligands, respectively. The molecular structures of 1, 2 and 3 have been determined by single-crystal X-ray diffraction analyses. The complexes 2 and 3 are efficient in catalyzing α-amination of ketones and esters through α-bromo carbonyl intermediate. The procedures are environmentally benign methods using molecular oxygen as an oxidant with water as the only byproduct. This journal is © the Partner Organisations 2014.

  7. Mathematical modelling of complex contagion on clustered networks

    Science.gov (United States)

    O'sullivan, David J.; O'Keeffe, Gary; Fennell, Peter; Gleeson, James

    2015-09-01

    The spreading of behavior, such as the adoption of a new innovation, is influenced bythe structure of social networks that interconnect the population. In the experiments of Centola (Science, 2010), adoption of new behavior was shown to spread further and faster across clustered-lattice networks than across corresponding random networks. This implies that the “complex contagion” effects of social reinforcement are important in such diffusion, in contrast to “simple” contagion models of disease-spread which predict that epidemics would grow more efficiently on random networks than on clustered networks. To accurately model complex contagion on clustered networks remains a challenge because the usual assumptions (e.g. of mean-field theory) regarding tree-like networks are invalidated by the presence of triangles in the network; the triangles are, however, crucial to the social reinforcement mechanism, which posits an increased probability of a person adopting behavior that has been adopted by two or more neighbors. In this paper we modify the analytical approach that was introduced by Hebert-Dufresne et al. (Phys. Rev. E, 2010), to study disease-spread on clustered networks. We show how the approximation method can be adapted to a complex contagion model, and confirm the accuracy of the method with numerical simulations. The analytical results of the model enable us to quantify the level of social reinforcement that is required to observe—as in Centola’s experiments—faster diffusion on clustered topologies than on random networks.

  8. Mathematical modelling of complex contagion on clustered networks

    Directory of Open Access Journals (Sweden)

    David J. P. O'Sullivan

    2015-09-01

    Full Text Available The spreading of behavior, such as the adoption of a new innovation, is influenced bythe structure of social networks that interconnect the population. In the experiments of Centola (Science, 2010, adoption of new behavior was shown to spread further and faster across clustered-lattice networks than across corresponding random networks. This implies that the complex contagion effects of social reinforcement are important in such diffusion, in contrast to simple contagion models of disease-spread which predict that epidemics would grow more efficiently on random networks than on clustered networks. To accurately model complex contagion on clustered networks remains a challenge because the usual assumptions (e.g. of mean-field theory regarding tree-like networks are invalidated by the presence of triangles in the network; the triangles are, however, crucial to the social reinforcement mechanism, which posits an increased probability of a person adopting behavior that has been adopted by two or more neighbors. In this paper we modify the analytical approach that was introduced by Hebert-Dufresne et al. (Phys. Rev. E, 2010, to study disease-spread on clustered networks. We show how the approximation method can be adapted to a complex contagion model, and confirm the accuracy of the method with numerical simulations. The analytical results of the model enable us to quantify the level of social reinforcement that is required to observe—as in Centola’s experiments—faster diffusion on clustered topologies than on random networks.

  9. Low-Complexity Bayesian Estimation of Cluster-Sparse Channels

    KAUST Repository

    Ballal, Tarig; Al-Naffouri, Tareq Y.; Ahmed, Syed

    2015-01-01

    This paper addresses the problem of channel impulse response estimation for cluster-sparse channels under the Bayesian estimation framework. We develop a novel low-complexity minimum mean squared error (MMSE) estimator by exploiting the sparsity of the received signal profile and the structure of the measurement matrix. It is shown that due to the banded Toeplitz/circulant structure of the measurement matrix, a channel impulse response, such as underwater acoustic channel impulse responses, can be partitioned into a number of orthogonal or approximately orthogonal clusters. The orthogonal clusters, the sparsity of the channel impulse response and the structure of the measurement matrix, all combined, result in a computationally superior realization of the MMSE channel estimator. The MMSE estimator calculations boil down to simpler in-cluster calculations that can be reused in different clusters. The reduction in computational complexity allows for a more accurate implementation of the MMSE estimator. The proposed approach is tested using synthetic Gaussian channels, as well as simulated underwater acoustic channels. Symbol-error-rate performance and computation time confirm the superiority of the proposed method compared to selected benchmark methods in systems with preamble-based training signals transmitted over clustersparse channels.

  10. Low-Complexity Bayesian Estimation of Cluster-Sparse Channels

    KAUST Repository

    Ballal, Tarig

    2015-09-18

    This paper addresses the problem of channel impulse response estimation for cluster-sparse channels under the Bayesian estimation framework. We develop a novel low-complexity minimum mean squared error (MMSE) estimator by exploiting the sparsity of the received signal profile and the structure of the measurement matrix. It is shown that due to the banded Toeplitz/circulant structure of the measurement matrix, a channel impulse response, such as underwater acoustic channel impulse responses, can be partitioned into a number of orthogonal or approximately orthogonal clusters. The orthogonal clusters, the sparsity of the channel impulse response and the structure of the measurement matrix, all combined, result in a computationally superior realization of the MMSE channel estimator. The MMSE estimator calculations boil down to simpler in-cluster calculations that can be reused in different clusters. The reduction in computational complexity allows for a more accurate implementation of the MMSE estimator. The proposed approach is tested using synthetic Gaussian channels, as well as simulated underwater acoustic channels. Symbol-error-rate performance and computation time confirm the superiority of the proposed method compared to selected benchmark methods in systems with preamble-based training signals transmitted over clustersparse channels.

  11. Synthesis and characterization of rhodium(I) complexes with P-N donor ligands and their catalytic application in transfer hydrogenation of carbonyl group

    Energy Technology Data Exchange (ETDEWEB)

    Barah, Geetika; Sarmah, Podma Poliov; Boruah, Devajani [Dept. of Chemistry, Dibrugarh University, Dibrugarh (India)

    2015-04-15

    Three rhodium(I) complexes of the types [Rh(COE)Cl(η{sup 2}-L)] (1a,1b) and [RhCl(η{sup 2}-L) (η{sup 1}-L)] (1c), where L = P⁓N donor ligands 2-[2-(diphenylphosphino) ethyl]pyridine, (PPh{sub 2}Etpy) (a), 2-(diphenylphosphino)pyridine (PPh{sub 2}py) (b), and 3-(diphenylphosphino)-1-propylamine (PPh{sub 2}(CH{sub 2}){sub 3}NH{sub 2}) (c), have been synthesized by reacting [Rh(coe){sub 2}Cl]{sub 2} with the respective ligands in 1:2 molar ratio for 1a, 1b and 1:4 molar ratio for 1c in DCM under refluxing condition. The complexes were characterized using different analytical techniques such as FT-IR, ESI(+) mass spectrometry, {sup 1}H and {sup 31}P{"1H} NMR spectrometry, conductivity measurements, and melting point determination. The synthesized complexes were found to exhibit good catalytic activity for the transfer hydrogenation of carbonyl compounds to corresponding alcohols with high conversion rate.

  12. Unusual saccharin-N,O (carbonyl) coordination in mixed-ligand copper(II) complexes: Synthesis, X-ray crystallography and biological activity

    Science.gov (United States)

    Mokhtaruddin, Nur Shuhada Mohd; Yusof, Enis Nadia Md; Ravoof, Thahira B. S. A.; Tiekink, Edward R. T.; Veerakumarasivam, Abhi; Tahir, Mohamed Ibrahim Mohamed

    2017-07-01

    Three tridentate Schiff bases containing N and S donor atoms were synthesized via the condensation reaction between S-2-methylbenzyldithiocarbazate with 2-acetyl-4-methylpyridine (S2APH); 4-methyl-3-thiosemicarbazide with 2-acetylpyridine (MT2APH) and 4-ethyl-3-thiosemicarbazide with 2-acetylpyridine (ET2APH). Three new, binuclear and mixed-ligand copper(II) complexes with the general formula, [Cu(sac)(L)]2 (sac = saccharinate anion; L = anion of the Schiff base) were then synthesized, and subsequently characterized by IR and UV/Vis spectroscopy as well as by molar conductivity and magnetic susceptibility measurements. The Schiff bases were also spectroscopically characterized using NMR and MS to further confirm their structures. The spectroscopic data indicated that the Schiff bases behaved as a tridentate NNS donor ligands coordinating via the pyridyl-nitrogen, azomethine-nitrogen and thiolate-sulphur atoms. Magnetic data indicated a square pyramidal environment for the complexes and the conductivity values showed that the complexes were essentially non-electrolytes in DMSO. The X-ray crystallographic analysis of one complex, [Cu(sac)(S2AP)]2 showed that the Cu(II) atom was coordinated to the thiolate-S, azomethine-N and pyridyl-N donors of the S2AP Schiff base and to the saccharinate-N from one anion, as well as to the carbonyl-O atom from a symmetry related saccharinate anion yielding a centrosymmetric binuclear complex with a penta-coordinate, square pyramidal geometry. All the copper(II) saccharinate complexes were found to display strong cytotoxic activity against the MCF-7 and MDA-MB-231 human breast cancer cell lines.

  13. Protein carbonylation in plants

    DEFF Research Database (Denmark)

    Møller, Ian Max; Havelund, Jesper; Rogowska-Wrzesinska, Adelina

    2017-01-01

    This chapter provides an overview of the current knowledge on protein carbonylation in plants and its role in plant physiology. It starts with a brief outline of the turnover and production sites of reactive oxygen species (ROS) in plants and the causes of protein carbonylation. This is followed...... by a description of the methods used to study protein carbonylation in plants, which is also very brief as the methods are similar to those used in studies on animals. The chapter also focuses on protein carbonylation in plants in general and in mitochondria and in seeds in particular, as case stories where...... specific carbonylated proteins have been identified. Protein carbonylation appears to accumulate at all stages of seed development and germination investigated to date. In some cases, such as seed aging, it is probably simply an accumulation of oxidative damage. However, in other cases protein...

  14. Which clustering algorithm is better for predicting protein complexes?

    Directory of Open Access Journals (Sweden)

    Moschopoulos Charalampos N

    2011-12-01

    Full Text Available Abstract Background Protein-Protein interactions (PPI play a key role in determining the outcome of most cellular processes. The correct identification and characterization of protein interactions and the networks, which they comprise, is critical for understanding the molecular mechanisms within the cell. Large-scale techniques such as pull down assays and tandem affinity purification are used in order to detect protein interactions in an organism. Today, relatively new high-throughput methods like yeast two hybrid, mass spectrometry, microarrays, and phage display are also used to reveal protein interaction networks. Results In this paper we evaluated four different clustering algorithms using six different interaction datasets. We parameterized the MCL, Spectral, RNSC and Affinity Propagation algorithms and applied them to six PPI datasets produced experimentally by Yeast 2 Hybrid (Y2H and Tandem Affinity Purification (TAP methods. The predicted clusters, so called protein complexes, were then compared and benchmarked with already known complexes stored in published databases. Conclusions While results may differ upon parameterization, the MCL and RNSC algorithms seem to be more promising and more accurate at predicting PPI complexes. Moreover, they predict more complexes than other reviewed algorithms in absolute numbers. On the other hand the spectral clustering algorithm achieves the highest valid prediction rate in our experiments. However, it is nearly always outperformed by both RNSC and MCL in terms of the geometrical accuracy while it generates the fewest valid clusters than any other reviewed algorithm. This article demonstrates various metrics to evaluate the accuracy of such predictions as they are presented in the text below. Supplementary material can be found at: http://www.bioacademy.gr/bioinformatics/projects/ppireview.htm

  15. Community detection in complex networks using proximate support vector clustering

    Science.gov (United States)

    Wang, Feifan; Zhang, Baihai; Chai, Senchun; Xia, Yuanqing

    2018-03-01

    Community structure, one of the most attention attracting properties in complex networks, has been a cornerstone in advances of various scientific branches. A number of tools have been involved in recent studies concentrating on the community detection algorithms. In this paper, we propose a support vector clustering method based on a proximity graph, owing to which the introduced algorithm surpasses the traditional support vector approach both in accuracy and complexity. Results of extensive experiments undertaken on computer generated networks and real world data sets illustrate competent performances in comparison with the other counterparts.

  16. The globular cluster system of NGC 1316. IV. Nature of the star cluster complex SH2

    Science.gov (United States)

    Richtler, T.; Husemann, B.; Hilker, M.; Puzia, T. H.; Bresolin, F.; Gómez, M.

    2017-05-01

    Context. The light of the merger remnant NGC 1316 (Fornax A) is dominated by old and intermediate-age stars. The only sign of current star formation in this big galaxy is the Hii region SH2, an isolated star cluster complex with a ring-like morphology and an estimated age of 0.1 Gyr at a galactocentric distance of about 35 kpc. A nearby intermediate-age globular cluster, surrounded by weak line emission and a few more young star clusters, is kinematically associated. The origin of this complex is enigmatic. Aims: We want to investigate the nature of this star cluster complex. The nebular emission lines permit a metallicity determination which can discriminate between a dwarf galaxy or other possible precursors. Methods: We used the Integral Field Unit (IFU) of the VIMOS instrument at the Very Large Telescope of the European Southern Observatory in high dispersion mode to study the morphology, kinematics, and metallicity employing line maps, velocity maps, and line diagnostics of a few characteristic spectra. Results: The line ratios of different spectra vary, indicating highly structured Hii regions, but define a locus of uniform metallicity. The strong-line diagnostic diagrams and empirical calibrations point to a nearly solar or even super-solar oxygen abundance. The velocity dispersion of the gas is highest in the region offset from the bright clusters. Star formation may be active on a low level. There is evidence for a large-scale disk-like structure in the region of SH2, which would make the similar radial velocity of the nearby globular cluster easier to understand. Conclusions: The high metallicity does not fit to a dwarf galaxy as progenitor. We favour the scenario of a free-floating gaseous complex having its origin in the merger 2 Gyr ago. Over a long period the densities increased secularly until finally the threshold for star formation was reached. SH2 illustrates how massive star clusters can form outside starbursts and without a considerable field

  17. Electronic structure of Ni-- and Ni2--ethylene cluster complexes

    International Nuclear Information System (INIS)

    Basch, H.; Newton, M.D.; Moskowitz, J.W.

    1978-01-01

    The electronic structure of metal cluster--ethylene complexes has been investigated by carrying out ab initio bonding pair-correlated, self-consistent field, and configuration interaction (CI) calculations on the NiC 2 H 4 and Ni 2 C 2 H 4 species. The π-NiC 2 H 4 and π-Ni 2 C 2 H 4 cluster complexes are found to be bound, the former only with CI, while disigma-Ni 2 C 2 H 4 has only a repulsive Ni 2 --C 2 H 4 ground state potential curve. The bonding in the π-type cluster complexes can be described as follows: The metal atom configuration is 3d 9 4s 1 with the 4s hybridized (by the metal 4p) away from the ethylene molecule, thereby allowing the π orbital to form a dative sigma bond with the metal atom. The bonding interaction is promoted by the presence of a second nickel atom behind the first one, leading to a 4s orbital electron deficiency of the bonded nickel atom and thus making this nickel atom a better electron acceptor. Back donation from the occupied metal 3d into the ethylene π* molecular orbital also takes place to some extent, and thus both features of the classical Dewar--Chatt--Duncanson model are observed. The π-Ni 2 C 2 H 4 species is analyzed in terms of the addition of a bare nickel atom to a π-NiC 2 H 4 cluster complex, with concomitant stabilization of the orbitals of the bonded nickel atom. A study of the excited electronic states of π-NiC 2 H 4 shows that low-lying 4s→π* and 3d→π* (M→L) charge transfer transitions are predicted. The former is not observed experimentally, probably due to the diffuse nature of the 4s orbital. The relationship between small cluster--ethylene complex systems and ethylene chemisorption on a nickel metal surface is discussed

  18. New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations

    Science.gov (United States)

    Prakash, Govindan; Viswanathamurthi, Periasamy

    2014-08-01

    Schiff base disulfide ligands (H2L1-6) were synthesized from the condensation of cystamine with salicylaldehyde(H2L1), 5-chlorosalicylaldehyde(H2L2), o-vanillin(H2L3), 2-hydroxyacetophenone(H2L4), 3-methyl-2-hydroxyacetophenone(H2L5), and 2-hydroxy-1-naphthaldehyde(H2L6). H2L1-6 reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L1-6]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR (1H and 13C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed.

  19. Synthesis, spectroscopic, DFT calculations and biological activity studies of ruthenium carbonyl complexes with 2-picolinic acid and a secondary ligand

    Science.gov (United States)

    Shohayeb, Shahera M.; Mohamed, Rania G.; Moustafa, H.; El-Medani, Samir M.

    2016-09-01

    Thermal reaction of [Ru3(CO)12] with 2-picolinic acid (Hpic) in the absence and presence of a secondary ligand (pyridine, Py, bipyridine, Bipy, or thiourea, Tu) was investigated. Four complexes with molecular formulae: [Ru(CO)3(Hpic)], 1, [Ru2(CO)5(Hpic)(Py)], 2, [Ru2(CO)5(Hpic)(Tu)], 3 and [Ru2(CO)4(Hpic)(Bipy)], 4, were isolated. All complexes were characterized based on elemental analyses, IR, 1H NMR, magnetic studies, mass spectrometry and thermal analysis. The ligand and its complexes have been screened for antibacterial activities. Density Functional Theory (DFT) calculations at the B3LYP/6-311G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligands. The optimized geometry parameters of the complexes were evaluated using B3LYP method and LANL2DZ basis set. The extent of natural charge population (core, valence and rydberg), exact electronic configuration, total Lewis and total non-Lewis are estimated and discussed in terms of natural bond orbitals (NBO) analysis.

  20. Efficient light-harvesting using non-carbonyl carotenoids: Energy transfer dynamics in the VCP complex from Nannochloropsis oceanica

    Czech Academy of Sciences Publication Activity Database

    Kesan, G.; Litvín, Radek; Bína, David; Durchan, Milan; Šlouf, V.; Polívka, Tomáš

    2016-01-01

    Roč. 1857, č. 4 (2016), s. 370-379 ISSN 0005-2728 R&D Projects: GA ČR(CZ) GAP205/11/1164; GA ČR GBP501/12/G055; GA ČR(CZ) GP14-01377P Institutional support: RVO:60077344 Keywords : Carotenoids * Energy transfer * Light-harvesting complex Subject RIV: BO - Biophysics Impact factor: 4.932, year: 2016

  1. A method for hydrogenating and carbonylizing unsaturated compounds in the presence of catalysts based on phosphine and metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, J C; Dyer, G

    1982-12-22

    The hydrogenation of unsaturated organic compounds or the attachment to them of CO is accomplished with contact with a synthesis gas in the presence of a stereospecific catalyst (Kt), a compound of a metal of the platinum group (preferably Rhodium, but also Platinum, Palladium, Ruthenium or Iridium) and an asymmetrical bis-phosphine of the formula A-(CH2)n-B, where A and B are phosphine groups. R2P and R'2P or RRhP, where R is an aryl radical, R' is aralkyl, alcarylic or alkyl radical, n = 1 to 10, or an asymmetrical monophosphine of the formula R2-R'P. The complex compound also includes Hydrogen, CO and (or) halogen (preferably Chlorine) as ligands. The physical properties of the obtained complex compounds of the carbonylchlorbisphosphines or Rh are presented: trans-(RhC1-(CO)(Ph2P(CH2)6PPh2))2; trans-(RhC1(CO)(C2H5PhP-(CH2)6PPh2))2; trans-(RhC1(CO)(cycloC6H11PhP(CH2)6-PPh2))2; trans-(RhC1(CO)(C2H5PhP(CH2)4PPh2)2; trans-(RhC1(CO)(C2H5PhP(Ch2))2 and PhC1(CO)4(p-C6H4CH2)2P(Ch2)6PPh2). The isolated complexes are light yellow crystalline substances.

  2. Merging Iron Catalysis and Biocatalysis-Iron Carbonyl Complexes as Efficient Hydrogen Autotransfer Catalysts in Dynamic Kinetic Resolutions

    KAUST Repository

    El-Sepelgy, Osama

    2016-09-29

    A dual catalytic iron/lipase system has been developed and applied in the dynamic kinetic resolution of benzylic and aliphatic secondary alcohols. A detailed study of the Knölker-type iron complexes demonstrated the hydrogen autotransfer of alcohols to proceed under mild reaction conditions and allowed the combination with the enzymatic resolution. Different racemic alcohols were efficiently converted to chiral acetates in good yields and with excellent enantioselectivities. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

  3. Merging Iron Catalysis and Biocatalysis-Iron Carbonyl Complexes as Efficient Hydrogen Autotransfer Catalysts in Dynamic Kinetic Resolutions

    KAUST Repository

    El-Sepelgy, Osama; Alandini, Nurtalya; Rueping, Magnus

    2016-01-01

    A dual catalytic iron/lipase system has been developed and applied in the dynamic kinetic resolution of benzylic and aliphatic secondary alcohols. A detailed study of the Knölker-type iron complexes demonstrated the hydrogen autotransfer of alcohols to proceed under mild reaction conditions and allowed the combination with the enzymatic resolution. Different racemic alcohols were efficiently converted to chiral acetates in good yields and with excellent enantioselectivities. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

  4. Kinetics of carbonyl reductase from human brain.

    OpenAIRE

    Bohren, K M; von Wartburg, J P; Wermuth, B

    1987-01-01

    Initial-rate analysis of the carbonyl reductase-catalysed reduction of menadione by NADPH gave families of straight lines in double-reciprocal plots consistent with a sequential mechanism being obeyed. The fluorescence of NADPH was increased up to 7-fold with a concomitant shift of the emission maximum towards lower wavelength in the presence of carbonyl reductase, and both NADPH and NADP+ caused quenching of the enzyme fluorescence, indicating formation of a binary enzyme-coenzyme complex. D...

  5. Pattern of occurrence and occupancy of carbonylation sites in proteins

    DEFF Research Database (Denmark)

    Rao, R Shyama Prasad; Møller, Ian Max

    2011-01-01

    sites. Comparison of metal-catalyzed oxidation of two closely related proteins indicates that this type of carbonylation might not be very specific in proteins. Interestingly, carbonylated sites show a very strong tendency to cluster together in the protein primary sequence hinting at some sort......Proteins are targets for modification by reactive oxygen species, and carbonylation is an important irreversible modification that increases during oxidative stress. While information on protein carbonylation is accumulating, its pattern is not yet understood. We have made a meta...

  6. Community Clustering Algorithm in Complex Networks Based on Microcommunity Fusion

    Directory of Open Access Journals (Sweden)

    Jin Qi

    2015-01-01

    Full Text Available With the further research on physical meaning and digital features of the community structure in complex networks in recent years, the improvement of effectiveness and efficiency of the community mining algorithms in complex networks has become an important subject in this area. This paper puts forward a concept of the microcommunity and gets final mining results of communities through fusing different microcommunities. This paper starts with the basic definition of the network community and applies Expansion to the microcommunity clustering which provides prerequisites for the microcommunity fusion. The proposed algorithm is more efficient and has higher solution quality compared with other similar algorithms through the analysis of test results based on network data set.

  7. Electrochemical Behaviour, IR Spectroelectrochemistry and Theoretical Studies of Tetracobalt Carbonyl Cluster Complexes with a Facial Cyclooctatetraene Ligand

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Jan; Nervi, C.; Osella, D.; Calhorda, M. J.; Godinho, S. M. C.; Merkel, R.; Wadepohl, H.

    - (2002), s. 3705-3711 ISSN 1472-7773 R&D Projects: GA MŠk OC D15.10 Institutional research plan: CEZ:AV0Z4040901 Keywords : spectroelectrochemistry * electron-transfer reactions Subject RIV: CG - Electrochemistry Impact factor: 3.023, year: 2002

  8. Protein Carbonylation and Adipocyte Mitochondrial Function*

    Science.gov (United States)

    Curtis, Jessica M.; Hahn, Wendy S.; Stone, Matthew D.; Inda, Jacob J.; Droullard, David J.; Kuzmicic, Jovan P.; Donoghue, Margaret A.; Long, Eric K.; Armien, Anibal G.; Lavandero, Sergio; Arriaga, Edgar; Griffin, Timothy J.; Bernlohr, David A.

    2012-01-01

    Carbonylation is the covalent, non-reversible modification of the side chains of cysteine, histidine, and lysine residues by lipid peroxidation end products such as 4-hydroxy- and 4-oxononenal. In adipose tissue the effects of such modifications are associated with increased oxidative stress and metabolic dysregulation centered on mitochondrial energy metabolism. To address the role of protein carbonylation in the pathogenesis of mitochondrial dysfunction, quantitative proteomics was employed to identify specific targets of carbonylation in GSTA4-silenced or overexpressing 3T3-L1 adipocytes. GSTA4-silenced adipocytes displayed elevated carbonylation of several key mitochondrial proteins including the phosphate carrier protein, NADH dehydrogenase 1α subcomplexes 2 and 3, translocase of inner mitochondrial membrane 50, and valyl-tRNA synthetase. Elevated protein carbonylation is accompanied by diminished complex I activity, impaired respiration, increased superoxide production, and a reduction in membrane potential without changes in mitochondrial number, area, or density. Silencing of the phosphate carrier or NADH dehydrogenase 1α subcomplexes 2 or 3 in 3T3-L1 cells results in decreased basal and maximal respiration. These results suggest that protein carbonylation plays a major instigating role in cytokine-dependent mitochondrial dysfunction and may be linked to the development of insulin resistance in the adipocyte. PMID:22822087

  9. Protein carbonylation and adipocyte mitochondrial function.

    Science.gov (United States)

    Curtis, Jessica M; Hahn, Wendy S; Stone, Matthew D; Inda, Jacob J; Droullard, David J; Kuzmicic, Jovan P; Donoghue, Margaret A; Long, Eric K; Armien, Anibal G; Lavandero, Sergio; Arriaga, Edgar; Griffin, Timothy J; Bernlohr, David A

    2012-09-21

    Carbonylation is the covalent, non-reversible modification of the side chains of cysteine, histidine, and lysine residues by lipid peroxidation end products such as 4-hydroxy- and 4-oxononenal. In adipose tissue the effects of such modifications are associated with increased oxidative stress and metabolic dysregulation centered on mitochondrial energy metabolism. To address the role of protein carbonylation in the pathogenesis of mitochondrial dysfunction, quantitative proteomics was employed to identify specific targets of carbonylation in GSTA4-silenced or overexpressing 3T3-L1 adipocytes. GSTA4-silenced adipocytes displayed elevated carbonylation of several key mitochondrial proteins including the phosphate carrier protein, NADH dehydrogenase 1α subcomplexes 2 and 3, translocase of inner mitochondrial membrane 50, and valyl-tRNA synthetase. Elevated protein carbonylation is accompanied by diminished complex I activity, impaired respiration, increased superoxide production, and a reduction in membrane potential without changes in mitochondrial number, area, or density. Silencing of the phosphate carrier or NADH dehydrogenase 1α subcomplexes 2 or 3 in 3T3-L1 cells results in decreased basal and maximal respiration. These results suggest that protein carbonylation plays a major instigating role in cytokine-dependent mitochondrial dysfunction and may be linked to the development of insulin resistance in the adipocyte.

  10. Effects of carbonyl bond, metal cluster dissociation, and evaporation rates on predictions of nanotube production in high-pressure carbon monoxide

    Science.gov (United States)

    Scott, Carl D.; Smalley, Richard E.

    2003-01-01

    The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon nanotubes (SWNTs) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the conformation of CO2. It is shown that the production of CO2 is significantly greater for FeCO because of its lower bond energy as compared with that of NiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence.

  11. Survey of the numerical characterisation of 2-D complex clusters

    NARCIS (Netherlands)

    Maggi, F.

    2003-01-01

    The study of cluster format ion is common in many fields of science and technology (aerosols, colloidal suspensions, hetero-disperse particulate systems in general, growth processes far from equilibrium, etc.). The term "cluster" is a general word indicating an object consisting of a set of

  12. Link-Prediction Enhanced Consensus Clustering for Complex Networks (Open Access)

    Science.gov (United States)

    2016-05-20

    RESEARCH ARTICLE Link-Prediction Enhanced Consensus Clustering for Complex Networks Matthew Burgess1*, Eytan Adar1,2, Michael Cafarella1 1Computer...consensus clustering algorithm to enhance community detection on incomplete networks. Our framework utilizes existing community detection algorithms that...types of complex networks exhibit community structure: groups of highly connected nodes. Communities or clusters often reflect nodes that share similar

  13. Reciprocal carbonyl-carbonyl interactions in small molecules and proteins.

    Science.gov (United States)

    Rahim, Abdur; Saha, Pinaki; Jha, Kunal Kumar; Sukumar, Nagamani; Sarma, Bani Kanta

    2017-07-19

    Carbonyl-carbonyl n→π* interactions where a lone pair (n) of the oxygen atom of a carbonyl group is delocalized over the π* orbital of a nearby carbonyl group have attracted a lot of attention in recent years due to their ability to affect the 3D structure of small molecules, polyesters, peptides, and proteins. In this paper, we report the discovery of a "reciprocal" carbonyl-carbonyl interaction with substantial back and forth n→π* and π→π* electron delocalization between neighboring carbonyl groups. We have carried out experimental studies, analyses of crystallographic databases and theoretical calculations to show the presence of this interaction in both small molecules and proteins. In proteins, these interactions are primarily found in polyproline II (PPII) helices. As PPII are the most abundant secondary structures in unfolded proteins, we propose that these local interactions may have implications in protein folding.Carbonyl-carbonyl π* non covalent interactions affect the structure and stability of small molecules and proteins. Here, the authors carry out experimental studies, analyses of crystallographic databases and theoretical calculations to describe an additional type of carbonyl-carbonyl interaction.

  14. Metagenomes of complex microbial consortia derived from different soils as sources for novel genes conferring formation of carbonyls from short-chain polyols on Escherichia coli.

    Science.gov (United States)

    Knietsch, Anja; Waschkowitz, Tanja; Bowien, Susanne; Henne, Anke; Daniel, Rolf

    2003-01-01

    Metagenomic DNA libraries from three different soil samples (meadow, sugar beet field, cropland) were constructed. The three unamplified libraries comprised approximately 1267000 independent clones and harbored approximately 4.05 Gbp of environmental DNA. Approximately 300000 recombinant Escherichia coli strains of each library per test substrate were screened for the production of carbonyls from short-chain (C2 to C4) polyols such as 1,2-ethanediol, 2,3-butanediol, and a mixture of glycerol and 1,2-propanediol on indicator agar. Twenty-four positive E. COLI clones were obtained during the initial screen. Fifteen of them contained recombinant plasmids, designated pAK201-215, which conferred a stable carbonyl-forming phenotype on E. coli Sequencing revealed that the inserts of pAK201-215 encoded 26 complete and 14 incomplete predicted protein-encoding genes. Most of these genes were similar to genes with unknown functions from other microorganisms or unrelated to any other known gene. The further analysis was focused on the 7 plasmids (pAK204, pAK206, pAK208, and pAK210-213) recovered from the positive clones, which exhibited an NAD(H)-dependent alcohol oxidoreductase activity with polyols or the correlating carbonyls as substrates in crude extracts. Three genes (ORF6, ORF24, and ORF25) conferring this activity were identified during subcloning of the inserts of pAK204, pAK211, and pAK212. The sequences of the three deduced gene products revealed no significant similarities to known alcohol oxidoreductases, but contained putative glycine-rich regions, which are characteristic for binding of nicotinamide cofactors. Copyright 2003 S. Karger AG, Basel

  15. Validation of protein carbonyl measurement

    DEFF Research Database (Denmark)

    Augustyniak, Edyta; Adam, Aisha; Wojdyla, Katarzyna

    2015-01-01

    Protein carbonyls are widely analysed as a measure of protein oxidation. Several different methods exist for their determination. A previous study had described orders of magnitude variance that existed when protein carbonyls were analysed in a single laboratory by ELISA using different commercial...... protein carbonyl analysis across Europe. ELISA and Western blotting techniques detected an increase in protein carbonyl formation between 0 and 5min of UV irradiation irrespective of method used. After irradiation for 15min, less oxidation was detected by half of the laboratories than after 5min...... irradiation. Three of the four ELISA carbonyl results fell within 95% confidence intervals. Likely errors in calculating absolute carbonyl values may be attributed to differences in standardisation. Out of up to 88 proteins identified as containing carbonyl groups after tryptic cleavage of irradiated...

  16. Generation of clusters in complex dynamical networks via pinning control

    International Nuclear Information System (INIS)

    Li Kezan; Fu Xinchu; Small, Michael

    2008-01-01

    Many real-world networks show community structure, i.e., groups (or clusters) of nodes that have a high density of links within them but with a lower density of links between them. In this paper, by applying feedback injections to a fraction of network nodes, various clusters are synchronized independently according to the community structure generated by the group partition of the network (cluster synchronization). This control is achieved by pinning (i.e. applying linear feedback control) to a subset of the network nodes. Those pinned nodes are selected not randomly but according to the topological structure of communities of a given network. Specifically, for a given group partition of a network, those nodes with direct connections between groups must be pinned in order to achieve cluster synchronization. Both the local stability and global stability of cluster synchronization are investigated. Taking the tree-shaped network and the most modular network as two particular examples, we illustrate in detail how the pinning strategy influences the generation of clusters. The simulations verify the efficiency of the pinning schemes used in this paper

  17. Effect of mitochondrial complex I inhibition on Fe-S cluster protein activity

    Energy Technology Data Exchange (ETDEWEB)

    Mena, Natalia P. [Department of Biology, Faculty of Sciences, Universidad de Chile, Las Palmeras 3425, Santiago (Chile); Millennium Institute of Cell Dynamics and Biotechnology, Santiago (Chile); Bulteau, Anne Laure [UPMC Univ Paris 06, UMRS 975 - UMR 7725, Centre de Recherche en Neurosciences, ICM, Therapeutique Experimentale de la Neurodegenerescence, Hopital de la Salpetriere, F-75005 Paris (France); Inserm, U 975, Centre de Recherche en Neurosciences, ICM, Therapeutique Experimentale de la Neurodegenerescence, Hopital de la Salpetriere, F-75005 Paris (France); CNRS, UMR 7225, Centre de Recherche en Neurosciences, ICM, Therapeutique Experimentale de la Neurodegenerescence, Hopital de la Salpetriere, F-75005 Paris (France); ICM, Therapeutique Experimentale de la Neurodegenerescence, Hopital de la Salpetriere, Paris 75013 (France); Salazar, Julio [Millennium Institute of Cell Dynamics and Biotechnology, Santiago (Chile); Hirsch, Etienne C. [UPMC Univ Paris 06, UMRS 975 - UMR 7725, Centre de Recherche en Neurosciences, ICM, Therapeutique Experimentale de la Neurodegenerescence, Hopital de la Salpetriere, F-75005 Paris (France); Inserm, U 975, Centre de Recherche en Neurosciences, ICM, Therapeutique Experimentale de la Neurodegenerescence, Hopital de la Salpetriere, F-75005 Paris (France); CNRS, UMR 7225, Centre de Recherche en Neurosciences, ICM, Therapeutique Experimentale de la Neurodegenerescence, Hopital de la Salpetriere, F-75005 Paris (France); ICM, Therapeutique Experimentale de la Neurodegenerescence, Hopital de la Salpetriere, Paris 75013 (France); Nunez, Marco T., E-mail: mnunez@uchile.cl [Department of Biology, Faculty of Sciences, Universidad de Chile, Las Palmeras 3425, Santiago (Chile); Millennium Institute of Cell Dynamics and Biotechnology, Santiago (Chile)

    2011-06-03

    Highlights: {yields} Mitochondrial complex I inhibition resulted in decreased activity of Fe-S containing enzymes mitochondrial aconitase and cytoplasmic aconitase and xanthine oxidase. {yields} Complex I inhibition resulted in the loss of Fe-S clusters in cytoplasmic aconitase and of glutamine phosphoribosyl pyrophosphate amidotransferase. {yields} Consistent with loss of cytoplasmic aconitase activity, an increase in iron regulatory protein 1 activity was found. {yields} Complex I inhibition resulted in an increase in the labile cytoplasmic iron pool. -- Abstract: Iron-sulfur (Fe-S) clusters are small inorganic cofactors formed by tetrahedral coordination of iron atoms with sulfur groups. Present in numerous proteins, these clusters are involved in key biological processes such as electron transfer, metabolic and regulatory processes, DNA synthesis and repair and protein structure stabilization. Fe-S clusters are synthesized mainly in the mitochondrion, where they are directly incorporated into mitochondrial Fe-S cluster-containing proteins or exported for cytoplasmic and nuclear cluster-protein assembly. In this study, we tested the hypothesis that inhibition of mitochondrial complex I by rotenone decreases Fe-S cluster synthesis and cluster content and activity of Fe-S cluster-containing enzymes. Inhibition of complex I resulted in decreased activity of three Fe-S cluster-containing enzymes: mitochondrial and cytosolic aconitases and xanthine oxidase. In addition, the Fe-S cluster content of glutamine phosphoribosyl pyrophosphate amidotransferase and mitochondrial aconitase was dramatically decreased. The reduction in cytosolic aconitase activity was associated with an increase in iron regulatory protein (IRP) mRNA binding activity and with an increase in the cytoplasmic labile iron pool. Since IRP activity post-transcriptionally regulates the expression of iron import proteins, Fe-S cluster inhibition may result in a false iron deficiency signal. Given that

  18. Effect of mitochondrial complex I inhibition on Fe-S cluster protein activity

    International Nuclear Information System (INIS)

    Mena, Natalia P.; Bulteau, Anne Laure; Salazar, Julio; Hirsch, Etienne C.; Nunez, Marco T.

    2011-01-01

    Highlights: → Mitochondrial complex I inhibition resulted in decreased activity of Fe-S containing enzymes mitochondrial aconitase and cytoplasmic aconitase and xanthine oxidase. → Complex I inhibition resulted in the loss of Fe-S clusters in cytoplasmic aconitase and of glutamine phosphoribosyl pyrophosphate amidotransferase. → Consistent with loss of cytoplasmic aconitase activity, an increase in iron regulatory protein 1 activity was found. → Complex I inhibition resulted in an increase in the labile cytoplasmic iron pool. -- Abstract: Iron-sulfur (Fe-S) clusters are small inorganic cofactors formed by tetrahedral coordination of iron atoms with sulfur groups. Present in numerous proteins, these clusters are involved in key biological processes such as electron transfer, metabolic and regulatory processes, DNA synthesis and repair and protein structure stabilization. Fe-S clusters are synthesized mainly in the mitochondrion, where they are directly incorporated into mitochondrial Fe-S cluster-containing proteins or exported for cytoplasmic and nuclear cluster-protein assembly. In this study, we tested the hypothesis that inhibition of mitochondrial complex I by rotenone decreases Fe-S cluster synthesis and cluster content and activity of Fe-S cluster-containing enzymes. Inhibition of complex I resulted in decreased activity of three Fe-S cluster-containing enzymes: mitochondrial and cytosolic aconitases and xanthine oxidase. In addition, the Fe-S cluster content of glutamine phosphoribosyl pyrophosphate amidotransferase and mitochondrial aconitase was dramatically decreased. The reduction in cytosolic aconitase activity was associated with an increase in iron regulatory protein (IRP) mRNA binding activity and with an increase in the cytoplasmic labile iron pool. Since IRP activity post-transcriptionally regulates the expression of iron import proteins, Fe-S cluster inhibition may result in a false iron deficiency signal. Given that inhibition of complex

  19. Detection of protein complex from protein-protein interaction network using Markov clustering

    International Nuclear Information System (INIS)

    Ochieng, P J; Kusuma, W A; Haryanto, T

    2017-01-01

    Detection of complexes, or groups of functionally related proteins, is an important challenge while analysing biological networks. However, existing algorithms to identify protein complexes are insufficient when applied to dense networks of experimentally derived interaction data. Therefore, we introduced a graph clustering method based on Markov clustering algorithm to identify protein complex within highly interconnected protein-protein interaction networks. Protein-protein interaction network was first constructed to develop geometrical network, the network was then partitioned using Markov clustering to detect protein complexes. The interest of the proposed method was illustrated by its application to Human Proteins associated to type II diabetes mellitus. Flow simulation of MCL algorithm was initially performed and topological properties of the resultant network were analysed for detection of the protein complex. The results indicated the proposed method successfully detect an overall of 34 complexes with 11 complexes consisting of overlapping modules and 20 non-overlapping modules. The major complex consisted of 102 proteins and 521 interactions with cluster modularity and density of 0.745 and 0.101 respectively. The comparison analysis revealed MCL out perform AP, MCODE and SCPS algorithms with high clustering coefficient (0.751) network density and modularity index (0.630). This demonstrated MCL was the most reliable and efficient graph clustering algorithm for detection of protein complexes from PPI networks. (paper)

  20. TOSCA-based orchestration of complex clusters at the IaaS level

    Science.gov (United States)

    Caballer, M.; Donvito, G.; Moltó, G.; Rocha, R.; Velten, M.

    2017-10-01

    This paper describes the adoption and extension of the TOSCA standard by the INDIGO-DataCloud project for the definition and deployment of complex computing clusters together with the required support in both OpenStack and OpenNebula, carried out in close collaboration with industry partners such as IBM. Two examples of these clusters are described in this paper, the definition of an elastic computing cluster to support the Galaxy bioinformatics application where the nodes are dynamically added and removed from the cluster to adapt to the workload, and the definition of an scalable Apache Mesos cluster for the execution of batch jobs and support for long-running services. The coupling of TOSCA with Ansible Roles to perform automated installation has resulted in the definition of high-level, deterministic templates to provision complex computing clusters across different Cloud sites.

  1. Linkage isomerism of carbonyl coordination complexes formed upon CO adsorption on the zeolite Li-ZSM-5: variable-temperature FTIR studies

    Science.gov (United States)

    Otero Areán, C.; Rodríguez Delgado, M.; Manoilova, O. V.; Turnes Palomino, G.; Tsyganenko, A. A.; Garrone, E.

    2002-08-01

    Carbon monoxide adsorbed at a low-temperature on the zeolite Li-ZSM-5 forms Li +⋯CO and Li +⋯(CO) 2 species characterized by C-O stretching bands at 2195 and 2187 cm-1, respectively. These C-bonded carbonyls are in a temperature-dependent equilibrium with Li +⋯OC and CO⋯Li +⋯CO species having O-bonded CO. By means of variable-temperature FTIR spectroscopy, the enthalpy change involved in the corresponding isomerization process was found to be ΔH°=7.8 kJ mol-1 for the monocarbonyl and ΔH°=5.1 kJ mol-1 for the dicarbonyl. Therefore, although C-bonded species were always found to show a higher cation-CO interaction energy than O-bonded species, the difference is smaller in the case of dicarbonyls.

  2. Electrocatalytic studies of osmium-ruthenium carbonyl cluster compounds for their application as methanol-tolerant cathodes for oxygen reduction reaction and carbon monoxide-tolerant anodes for hydrogen oxidation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Borja-Arco, E.; Uribe-Godinez, J.; Castellanos, R.H. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Escobedo (Mexico); Altamirano-Gutierrez, A.; Jimenez-Sandoval, O. [Centro de Investigacion y de Estudios Avanzados del Inst. Politecnico Nacional, Querataro (Mexico)

    2006-07-01

    This paper provided details of an electrokinetic study of novel electrocatalytic materials capable of performing both the oxygen reduction reaction (ORR) and the hydrogen oxidation reaction (HOR). Osmium-ruthenium carbonyl cluster compounds (Os{sub x}Ru{sub 3}(CO){sub n}) were synthesized by chemical condensation in non-polar organic solvents at different boiling points and refluxing temperatures. Three different non-polar organic solvents were used: (1) n-nonane; o-xylene; and 1,2-dichlorobenzene. The electrocatalysts were characterized by Fourier Transform Infra-red (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). A rotating disk electrode technique was used to analyze the materials. Results of the analysis showed that the materials performed ORR in both the presence and absence of carbon monoxide (CO), and that electrocatalysts were not poisoned by the presence of CO. Cyclic voltamperometry for the disk electrodes showed that the electrochemical behaviour of the compounds in the acid electrolyte was similar in the presence or absence of methanol. The Tafel slope, exchange current density and the transfer coefficient were also investigated. The electrokinetic parameters for the ORR indicated that the materials with the highest electrocatalytic activity were synthesized in 1,2-dichlorobenzene. Electrocatalytic activity during HOR were prepared in n-nonane. It was concluded that the new materials are good candidates for use as both a cathode and an anode in proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). 7 refs., 2 tabs., 7 figs.

  3. A density-based clustering model for community detection in complex networks

    Science.gov (United States)

    Zhao, Xiang; Li, Yantao; Qu, Zehui

    2018-04-01

    Network clustering (or graph partitioning) is an important technique for uncovering the underlying community structures in complex networks, which has been widely applied in various fields including astronomy, bioinformatics, sociology, and bibliometric. In this paper, we propose a density-based clustering model for community detection in complex networks (DCCN). The key idea is to find group centers with a higher density than their neighbors and a relatively large integrated-distance from nodes with higher density. The experimental results indicate that our approach is efficient and effective for community detection of complex networks.

  4. Study of selective Fischer-Tropsch catalysts synthesized by the destruction of bimetallic carbonyl complexes on activated γ-Al2O3 support

    International Nuclear Information System (INIS)

    Maksimov, Yu.V.; Matveev, V.V.; Suzdalev, I.P.; Khomenko, T.I.; Kadushin, A.A.

    1990-01-01

    The bimetallic catalysts obtained by the deposition of a Fe-Co binuclear cluster on the dehydroxylated γ-Al 2 O 3 are studied and compared to some other relative systems. These bimetallic catalysts are found to be active and selective in olefin synthesis. This is connected with the formation of Fe-Co contact which is detectable by Moessbauer spectroscopy. (orig.)

  5. Discovery of Multiseeded Multimode Formation of Embedded Clusters in the Rosette Molecular Complex

    Science.gov (United States)

    Li, Jin Zeng; Smith, Michael D.

    2005-02-01

    An investigation based on data from the spatially complete Two Micron All Sky Survey (2MASS) reveals that a remarkable burst of clustered star formation is taking place throughout the southeast quadrant of the Rosette Molecular Cloud. Compact clusters are forming in a multiseeded mode, in parallel and at various places. In addition, sparse aggregates of embedded young stars are extensively distributed. In this study we report the primary results and implications for high-mass and clustered star formation in giant molecular clouds. In particular, we incorporate for the first time the birth of medium- to low-mass stars into the scenario of sequential formation of OB clusters. Following the emergence of the young OB cluster NGC 2244, a variety of manifestations of forming clusters of medium to high mass appears in the vicinity of the swept-up layer of the H II region as well as farther into the molecular cloud. The embedded clusters appear to form in a structured manner, which suggests they follow tracks laid out by the decay of macroturbulence. We address the possible origins of the turbulence. This leads us to propose a tree model to interpret the neat spatial distribution of clusters within a large section of the Rosette complex. Prominent new-generation OB clusters are identified at the root of the tree pattern.

  6. Synthesis and characterization of bisoxazolines- and pybox-copper(II) complexes and their application in the coupling of α-carbonyls with functionalized amines

    KAUST Repository

    Jia, Weiguo; Li, Dandan; Dai, Yuanchen; Zhang, Hui; Yan, Liqin; Sheng, Enhong; Wei, Yun; Mu, Xiaolong; Huang, Kuo-Wei

    2014-01-01

    Binuclear complexes [{(DMOX)CuCl}2(μ-Cl)2] (1), mononuclear complexes [(DMOX)CuBr2] (2) (DMOX = 4,5-dihydro-2-(4,5- dihydro-4,4-dimethyloxazol-2-yl)-4,4-dimethyloxazole) and the pybox Cu(ii) complex [(Dm-Pybox)CuBr2] (3) (Dm-Pybox = 2,6-bis[4′,4

  7. Reactions of the dirhenium(II) complexes Re2X4(dppm)2 (X = Cl, Br; dppm = Ph2PCH2PPh2) with isocyanides. 5. Mixed carbonyl-isocyanide and carbonyl-isocyanide-nitrile complexes of stoichiometry (Re2Cl3(dppm)2(CO)(CNR)(L))PF6 (R = t-Bu, xyl (Xylyl); L = t-BuNC, xylNC, MeCN, EtCN). Structural characterization of the cation (Cl2(CO)Re(μ-dppm)2ReCl (CN-t-Bu)2)+

    International Nuclear Information System (INIS)

    Fanwick, P.E.; Price, A.C.; Walton, R.A.

    1988-01-01

    Several dirhenium (II) species that contain mixed sets of carbonyl, isocyanide, and/or nitrile ligands have been prepared from the reactions between Re 2 Cl 4 (dppm) 2 (CO)(CNR) (dppm = Ph 2 PCHPPh 2 ; R = t-Bu, xyl (xylyl)), and the appropriate ligands in the presence of TlPF 6 . The crystal structures of these compounds are reported. The terminally-bound ligand noted in the complexes (Re 2 Cl 3 (dppm) 2 (CO)(CN-t-Bu) 2 )PF 6 and (Re 2 CL 3 (dppm) 2 (CO)(CN-t-Bu)(CNxyl))PF 6 indicates structures that have not been previously reported. Complexes in which there are mixed sets of carbonyl, isocyanide, and nitrile ligands, viz. (Re 2 Cl 3 (dppm) 2 (CO)(CNR)(CNR'))PF 6 are also reported. 20 refs., 1 fig., 5 tabs

  8. Novel approaches to pin cluster synchronization on complex dynamical networks in Lur'e forms

    Science.gov (United States)

    Tang, Ze; Park, Ju H.; Feng, Jianwen

    2018-04-01

    This paper investigates the cluster synchronization of complex dynamical networks consisted of identical or nonidentical Lur'e systems. Due to the special topology structure of the complex networks and the existence of stochastic perturbations, a kind of randomly occurring pinning controller is designed which not only synchronizes all Lur'e systems in the same cluster but also decreases the negative influence among different clusters. Firstly, based on an extended integral inequality, the convex combination theorem and S-procedure, the conditions for cluster synchronization of identical Lur'e networks are derived in a convex domain. Secondly, randomly occurring adaptive pinning controllers with two independent Bernoulli stochastic variables are designed and then sufficient conditions are obtained for the cluster synchronization on complex networks consisted of nonidentical Lur'e systems. In addition, suitable control gains for successful cluster synchronization of nonidentical Lur'e networks are acquired by designing some adaptive updating laws. Finally, we present two numerical examples to demonstrate the validity of the control scheme and the theoretical analysis.

  9. Directed clustering coefficient as a measure of systemic risk in complex banking networks

    Science.gov (United States)

    Tabak, Benjamin M.; Takami, Marcelo; Rocha, Jadson M. C.; Cajueiro, Daniel O.; Souza, Sergio R. S.

    2014-01-01

    Recent literature has focused on the study of systemic risk in complex networks. It is clear now, after the crisis of 2008, that the aggregate behavior of the interaction among agents is not straightforward and it is very difficult to predict. Contributing to this debate, this paper shows that the directed clustering coefficient may be used as a measure of systemic risk in complex networks. Furthermore, using data from the Brazilian interbank network, we show that the directed clustering coefficient is negatively correlated with domestic interest rates.

  10. Looping and clustering model for the organization of protein-DNA complexes on the bacterial genome

    Science.gov (United States)

    Walter, Jean-Charles; Walliser, Nils-Ole; David, Gabriel; Dorignac, Jérôme; Geniet, Frédéric; Palmeri, John; Parmeggiani, Andrea; Wingreen, Ned S.; Broedersz, Chase P.

    2018-03-01

    The bacterial genome is organized by a variety of associated proteins inside a structure called the nucleoid. These proteins can form complexes on DNA that play a central role in various biological processes, including chromosome segregation. A prominent example is the large ParB-DNA complex, which forms an essential component of the segregation machinery in many bacteria. ChIP-Seq experiments show that ParB proteins localize around centromere-like parS sites on the DNA to which ParB binds specifically, and spreads from there over large sections of the chromosome. Recent theoretical and experimental studies suggest that DNA-bound ParB proteins can interact with each other to condense into a coherent 3D complex on the DNA. However, the structural organization of this protein-DNA complex remains unclear, and a predictive quantitative theory for the distribution of ParB proteins on DNA is lacking. Here, we propose the looping and clustering model, which employs a statistical physics approach to describe protein-DNA complexes. The looping and clustering model accounts for the extrusion of DNA loops from a cluster of interacting DNA-bound proteins that is organized around a single high-affinity binding site. Conceptually, the structure of the protein-DNA complex is determined by a competition between attractive protein interactions and loop closure entropy of this protein-DNA cluster on the one hand, and the positional entropy for placing loops within the cluster on the other. Indeed, we show that the protein interaction strength determines the ‘tightness’ of the loopy protein-DNA complex. Thus, our model provides a theoretical framework for quantitatively computing the binding profiles of ParB-like proteins around a cognate (parS) binding site.

  11. Near-infrared study of new embedded clusters in the Carina complex

    Science.gov (United States)

    Oliveira, R. A. P.; Bica, E.; Bonatto, C.

    2018-05-01

    We analyse the nature of a sample of stellar overdensities that we found projected on the Carina complex. This study is based on the Two Micron All Sky Survey photometry and involves the photometry decontamination of field stars, elaboration of intrinsic colour-magnitude diagrams [CMDs; J × (J - Ks)], colour-colour diagrams (J - H) × (H - Ks), and radial density profiles, in order to determine the structure and the main astrophysical parameters of the best candidates. The verification of an overdensity as an embedded cluster requires a CMD consistent with a PMS content and MS stars, if any. From these results, we are able to verify if they are, in fact, embedded clusters. The results were, in general, rewarding: in a sample of 101 overdensities, the analysis provided 15 candidates, of which three were previously catalogued as clusters (CCCP-Cl 16, Treasure Chest, and FSR 1555), and the 12 remaining are discoveries that provided significant results, with ages not above 4.5 Myr and distances compatible with the studied complex. The resulting values for the differential reddening of most candidates were relatively high, confirming that these clusters are still (partially or fully) embedded in the surrounding gas and dust, as a rule within a shell. Histograms with the distribution of the masses, ages, and distances were also produced, to give an overview of the results. We conclude that all the 12 newly found embedded clusters are related to the Carina complex.

  12. Selective Oxidative Carbonylation of Aniline to Diphenylurea with Ionic Liquids

    DEFF Research Database (Denmark)

    Zahrtmann, Nanette; Claver, Carmen; Godard, Cyril

    2018-01-01

    A catalytic system for the selective oxidative carbonylation of aniline to diphenylurea based on Pd complexes in combination with imidazolium ionic liquids is presented. Both oxidants, Pd complexes and ionic liquids affect the activity of the reaction while the choice of oxidant determines...

  13. Energy transfer and clustering of photosynthetic light-harvesting complexes in reconstituted lipid membranes

    International Nuclear Information System (INIS)

    Dewa, Takehisa; Sumino, Ayumi; Watanabe, Natsuko; Noji, Tomoyasu; Nango, Mamoru

    2013-01-01

    Highlights: ► Photosynthetic light-harvesting complexes were reconstituted into lipid membranes. ► Energy transfers between light-harvesting complexes were examined. ► Atomic force microscopy indicated cluster formation of light-harvesting complexes. ► Efficient energy transfer was observed for the clustered complexes in the membranes. - Abstract: In purple photosynthetic bacteria, light-harvesting complex 2 (LH2) and light harvesting/reaction centre core complex (LH1-RC) play the key roles of capturing and transferring light energy and subsequent charge separation. These photosynthetic apparatuses form a supramolecular assembly; however, how the assembly influences the efficiency of energy conversion is not yet clear. We addressed this issue by evaluating the energy transfer in reconstituted photosynthetic protein complexes LH2 and LH1-RC and studying the structures and the membrane environment of the LH2/LH1-RC assemblies, which had been embedded into various lipid bilayers. Thus, LH2 and LH1-RC from Rhodopseudomonas palustris 2.1.6 were reconstituted in phosphatidylglycerol (PG), phosphatidylcholine (PC), and phosphatidylethanolamine (PE)/PG/cardiolipin (CL). Efficient energy transfer from LH2 to LH1-RC was observed in the PC and PE/PG/CL membranes. Atomic force microscopy revealed that LH2 and LH1-RC were heterogeneously distributed to form clusters in the PC and PE/PG/CL membranes. The results indicated that the phospholipid species influenced the cluster formation of LH2 and LH1-RC as well as the energy transfer efficiency

  14. Energy transfer and clustering of photosynthetic light-harvesting complexes in reconstituted lipid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Dewa, Takehisa, E-mail: takedewa@nitech.ac.jp [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Japan Science and Technology, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012 (Japan); Sumino, Ayumi; Watanabe, Natsuko; Noji, Tomoyasu [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Nango, Mamoru, E-mail: nango@nitech.ac.jp [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2013-06-20

    Highlights: ► Photosynthetic light-harvesting complexes were reconstituted into lipid membranes. ► Energy transfers between light-harvesting complexes were examined. ► Atomic force microscopy indicated cluster formation of light-harvesting complexes. ► Efficient energy transfer was observed for the clustered complexes in the membranes. - Abstract: In purple photosynthetic bacteria, light-harvesting complex 2 (LH2) and light harvesting/reaction centre core complex (LH1-RC) play the key roles of capturing and transferring light energy and subsequent charge separation. These photosynthetic apparatuses form a supramolecular assembly; however, how the assembly influences the efficiency of energy conversion is not yet clear. We addressed this issue by evaluating the energy transfer in reconstituted photosynthetic protein complexes LH2 and LH1-RC and studying the structures and the membrane environment of the LH2/LH1-RC assemblies, which had been embedded into various lipid bilayers. Thus, LH2 and LH1-RC from Rhodopseudomonas palustris 2.1.6 were reconstituted in phosphatidylglycerol (PG), phosphatidylcholine (PC), and phosphatidylethanolamine (PE)/PG/cardiolipin (CL). Efficient energy transfer from LH2 to LH1-RC was observed in the PC and PE/PG/CL membranes. Atomic force microscopy revealed that LH2 and LH1-RC were heterogeneously distributed to form clusters in the PC and PE/PG/CL membranes. The results indicated that the phospholipid species influenced the cluster formation of LH2 and LH1-RC as well as the energy transfer efficiency.

  15. Existence of both blue-shifting hydrogen bond and Lewis acid-base interaction in the complexes of carbonyls and thiocarbonyls with carbon dioxide.

    Science.gov (United States)

    Nguyen, Tien Trung; Nguyen, Phi Hung; Tran, Thanh Hue; Minh, Tho Nguyen

    2011-08-21

    In this study, 16 gas phase complexes of the pairs of XCHZ and CO(2) (X = F, Cl, Br; Z = O, S) have been identified. Interaction energies calculated at the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ level including both BSSE and ZPE corrections range from -5.6 to -10.5 kJ mol(-1) for XCHOCO(2) and from -5.7 to -9.1 kJ mol(-1) for XCHS···CO(2). Substitution of one H atom by one halogen in formaldehyde and thioformaldehyde reduces the interaction energy of XCHZ···CO(2), while a CH(3) substitution increases the interaction energy of both CH(3)CHO···CO(2) and CH(3)CHS···CO(2). NBO and AIM analyses also point out that the strength of Lewis acid-base interactions decreases going from >C1=S3···C6 to >C1=O3C6 and to >C1-X4···C6. This result suggests the higher capacity of solubility of thiocarbonyl compounds in scCO(2), providing an enormous potential application for designing CO(2)-philic materials based on the >C=S functional group in competition with >C=O. The Lewis acid-base interaction of the types >C=S···C, >C-Cl···C and >C-Br···C is demonstrated for the first time. The contribution of the hydrogen bonding interaction to the total interaction energy is larger for XCHS···CO(2) than for XCHO···CO(2). Upon complexation, a contraction of the C1-H2 bond length and a blue shift of its stretching frequency have been observed, as compared to the isolated monomer, indicating the existence of a blue-shifting hydrogen bond in all complexes examined. Calculated results also lend further support for the viewpoint that when acting as proton donor, a C-H bond having a weaker polarization will induce a stronger distance contraction and frequency blue shift upon complexation, and vice versa.

  16. Structural Properties and UV-Visible Absorption Spectroscopy of Retinal-pyridyl-CN Re(I) Carbonyl Bipyridine Complex: A Theoretical Study.

    Science.gov (United States)

    Eng, Julien; Daniel, Chantal

    2015-10-29

    The structural, electronic, and optical properties of the all-trans and five cis conformers of [Re(CO)3(bpy)(ret-pyr-CN)](+) (bpy = 2,2'-bipyridine; ret-pyr-CN = pyridyl-CN-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-2-n)-none-(2,4,6,8-tetraen) were studied in solvent by means of density functional theory (DFT) and time-dependent DFT. The isolated retinal-like chromophore ret-pyr-CN was investigated as well for comparison. By coordination to the complex the two lowest intraligand (IL) states localized on the retinal group are slightly red-shifted from 627 to 690 nm and from 415 to 450 nm, respectively. Several isomerization pathways are open upon irradiation of the Re(I) complex by visible light (400-450 nm), especially to two cis conformers corresponding to the isomerization of the two double bonds of the retinal-like ligand close to the pyridyl group linked to the Re(I) fragment. The metal-to-ligand charge transfer states localized either on the retinal group or on the bpy ligand should play a minor role in the isomerization process itself but could improve its efficiency via ultra-fast intersystem crossing.

  17. Comparative study of the anchorage and the catalytic properties of nanoporous TiO2 films modified with ruthenium (II) and rhenium (I) carbonyl complexes

    Science.gov (United States)

    Oyarzún, Diego P.; Chardon-Noblat, Sylvie; Linarez Pérez, Omar E.; López Teijelo, Manuel; Zúñiga, César; Zarate, Ximena; Shott, Eduardo; Carreño, Alexander; Arratia-Perez, Ramiro

    2018-02-01

    In this article we study the anchoring of cis-[Ru(bpyC4pyr)(CO)2(CH3CN)2]2+, cis-[Ru(bpy)2(CO)2]2+ and cis-[Ru(bpyac)(CO)2Cl2], onto nanoporous TiO2 employing electropolymerization, electrostatic interaction and chemical bonding. Also, the [Re(bpyac)(CO)3Cl] rhenium(I) complex for chemical anchorage was analyzed. The characterization of TiO2/Ru(II) and TiO2/Re(I) nanocomposite films was performed by field emission scanning electron microscopy (FESEM), electron dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. In addition, for the more stable nanocomposites obtained, the catalytic properties (solar energy conversion and CO2 reduction) were evaluated. The efficiency improvement in redox process derived from the (photo)electrochemical evidence indicates that modified nanoporous TiO2 structures enhance the rate of charge transfer reactions.

  18. Alignment and integration of complex networks by hypergraph-based spectral clustering

    Science.gov (United States)

    Michoel, Tom; Nachtergaele, Bruno

    2012-11-01

    Complex networks possess a rich, multiscale structure reflecting the dynamical and functional organization of the systems they model. Often there is a need to analyze multiple networks simultaneously, to model a system by more than one type of interaction, or to go beyond simple pairwise interactions, but currently there is a lack of theoretical and computational methods to address these problems. Here we introduce a framework for clustering and community detection in such systems using hypergraph representations. Our main result is a generalization of the Perron-Frobenius theorem from which we derive spectral clustering algorithms for directed and undirected hypergraphs. We illustrate our approach with applications for local and global alignment of protein-protein interaction networks between multiple species, for tripartite community detection in folksonomies, and for detecting clusters of overlapping regulatory pathways in directed networks.

  19. Synthesis of molecular hexatechnetium clusters by means of dimensional reduction of their polymeric complexes

    International Nuclear Information System (INIS)

    Ikai, T.; Yoshimura, T.; Shinohara, A.; Takayama, T.; Sekine, T.

    2006-01-01

    Selenide capping hexatechnetium cluster complex [Tc 6 (μ 3 -Se) 8 CN 6 ] 4- (1) was prepared by the reactions of one-dimensional polymer complex [Tc 6 (μ 3 -Se) 8 Br 4 ] 2- and cyanides at high temperature. Similar reaction of sulfide capping hexatechnetium cluster complex, [Tc 6 (μ 3 -S) 8 Br 6 ] 4- with cyanide gave the terminal substituted complex [Tc 6 (μ 3 -S) 8 CN 6 ] 4- (2). The single-crystal X-ray analysis of 1 and 2, showed that the Tc-Tc bond lengths become longer with lager ionic radius of the face capping ligands in the order S -1 , and that of 2 showed it at 2119 cm -1 . Each of cyclic voltammogram of 1 and 2 showed a reversible one electron redox wave assignable to the Tc 6 III /Tc 5 III Tc IV process. These redox potentials shift to the positive about 0.4V compared to those of the Re cluster analogs. (author)

  20. Characterization of a Novel 99mTc-Carbonyl Complex as a Functional Probe of MDR1 P-Glycoprotein Transport Activity

    Directory of Open Access Journals (Sweden)

    Mary Dyszlewski

    2002-01-01

    Full Text Available Multidrug resistance (MDR mediated by overexpression of MDR1 P-glycoprotein (Pgp is one of the best characterized barriers to chemotherapy in cancer patients. Furthermore, the protective function of Pgp-mediated efflux of xenobiotics in various organs has a profound effect on the bioavailability of drugs in general. Thus, there is an expanding requirement to noninvasively interrogate Pgp transport activity in vivo. We herein report the Pgp recognition properties of a novel 99mTc(I-tricarbonyl complex, [99mTc(CO3(MIBI3] + (Tc-CO-MIBI. Tc-CO-MIBI showed 60-fold higher accumulation in drug-sensitive KB 3–1 cells compared to colchicine-selected drug-resistant KB 8-5 cells. In KB 8-5 cells, tracer enhancement was observed with the potent MDR modulator LY335979 (EC50 = 62 nM. Similar behavior was observed using drug-sensitive MCF-7 breast adenocarcinoma cells and MCF-7/MDR1 stable transfectants, confirming that Tc-CO-MIBI is specifically excluded by overexpression of MDR1 Pgp. By comparison, net accumulation in control H69 lung tumor cells was 9-fold higher than in MDR-associated protein (MRP1-expressing H69AR cells, indicating only modest transport by MRP1. Biodistribution analysis following tail vein injection of Tc-CO-MIBI showed delayed liver clearance as well as enhanced brain uptake and retention in mdr1a/1b(−/− gene deleted mice versus wild-type mice, directly demonstrating that Tc-CO-MIBI is a functional probe of Pgp transport activity in vivo.

  1. Segregation and Clustering Effects on Complex Boron Redistribution in Strongly Doped Polycrystalline-Silicon Layers

    International Nuclear Information System (INIS)

    Abadli, S.; Mansour, F.

    2011-01-01

    This work deals with the investigation of the complex phenomenon of boron (B) transient enhanced diffusion (TED) in strongly implanted silicon (Si) layers. It concerns the instantaneous influences of the strong B concentrations, the Si layers crystallization, the clustering and the B trapping/segregation during thermal post-implantation annealing. We have used Si thin layers obtained from disilane (Si2H6) by low pressure chemical vapor deposition (LPCVD) and then B implanted with a dose of 4 x 1015 atoms/cm2 at an energy of 15 keV. To avoid long redistributions, thermal annealing was carried out at relatively low-temperatures (700, 750 and 800 'deg'C) for various short-times ranging between 1 and 30 minutes. To investigate the experimental secondary ion mass spectroscopy (SIMS) doping profiles, a redistribution model well adapted to the particular structure of Si-LPCVD layers and to the effects of strong-concentrations has been established. The good adjustment of the simulated profiles with the experimental SIMS profiles allowed a fundamental understanding about the instantaneous physical phenomena giving and disturbing the TED process in strongly doped Si-LPCVD layers. It was found that boron TED is strongly affected by the simultaneous complex kinetics of clustering, crystallization, trapping and segregation during annealing. The fast formation of small Si-B clusters enhances the B diffusivity whereas the evolution of the clusters and segregation reduce this enhancement. (author)

  2. Gene expression patterns of oxidative phosphorylation complex I subunits are organized in clusters.

    Directory of Open Access Journals (Sweden)

    Yael Garbian

    Full Text Available After the radiation of eukaryotes, the NUO operon, controlling the transcription of the NADH dehydrogenase complex of the oxidative phosphorylation system (OXPHOS complex I, was broken down and genes encoding this protein complex were dispersed across the nuclear genome. Seven genes, however, were retained in the genome of the mitochondrion, the ancient symbiote of eukaryotes. This division, in combination with the three-fold increase in subunit number from bacteria (N = approximately 14 to man (N = 45, renders the transcription regulation of OXPHOS complex I a challenge. Recently bioinformatics analysis of the promoter regions of all OXPHOS genes in mammals supported patterns of co-regulation, suggesting that natural selection favored a mechanism facilitating the transcriptional regulatory control of genes encoding subunits of these large protein complexes. Here, using real time PCR of mitochondrial (mtDNA- and nuclear DNA (nDNA-encoded transcripts in a panel of 13 different human tissues, we show that the expression pattern of OXPHOS complex I genes is regulated in several clusters. Firstly, all mtDNA-encoded complex I subunits (N = 7 share a similar expression pattern, distinct from all tested nDNA-encoded subunits (N = 10. Secondly, two sub-clusters of nDNA-encoded transcripts with significantly different expression patterns were observed. Thirdly, the expression patterns of two nDNA-encoded genes, NDUFA4 and NDUFA5, notably diverged from the rest of the nDNA-encoded subunits, suggesting a certain degree of tissue specificity. Finally, the expression pattern of the mtDNA-encoded ND4L gene diverged from the rest of the tested mtDNA-encoded transcripts that are regulated by the same promoter, consistent with post-transcriptional regulation. These findings suggest, for the first time, that the regulation of complex I subunits expression in humans is complex rather than reflecting global co-regulation.

  3. Interdependence of laminin-mediated clustering of lipid rafts and the dystrophin complex in astrocytes.

    Science.gov (United States)

    Noël, Geoffroy; Tham, Daniel Kai Long; Moukhles, Hakima

    2009-07-17

    Astrocyte endfeet surrounding blood vessels are active domains involved in water and potassium ion transport crucial to the maintenance of water and potassium ion homeostasis in brain. A growing body of evidence points to a role for dystroglycan and its interaction with perivascular laminin in the targeting of the dystrophin complex and the water-permeable channel, aquaporin 4 (AQP4), at astrocyte endfeet. However, the mechanisms underlying such compartmentalization remain poorly understood. In the present study we found that AQP4 resided in Triton X-100-insoluble fraction, whereas dystroglycan was recovered in the soluble fraction in astrocytes. Cholesterol depletion resulted in the translocation of a pool of AQP4 to the soluble fraction indicating that its distribution is indeed associated with cholesterol-rich membrane domains. Upon laminin treatment AQP4 and the dystrophin complex, including dystroglycan, reorganized into laminin-associated clusters enriched for the lipid raft markers GM1 and flotillin-1 but not caveolin-1. Reduced diffusion rates of GM1 in the laminin-induced clusters were indicative of the reorganization of raft components in these domains. In addition, both cholesterol depletion and dystroglycan silencing reduced the number and area of laminin-induced clusters of GM1, AQP4, and dystroglycan. These findings demonstrate the interdependence between laminin binding to dystroglycan and GM1-containing lipid raft reorganization and provide novel insight into the dystrophin complex regulation of AQP4 polarization in astrocytes.

  4. Radical carbonylations using a continuous microflow system

    Directory of Open Access Journals (Sweden)

    Takahide Fukuyama

    2009-07-01

    Full Text Available Radical-based carbonylation reactions of alkyl halides were conducted in a microflow reactor under pressurized carbon monoxide gas. Good to excellent yields of carbonylated products were obtained via radical formylation, carbonylative cyclization and three-component coupling reactions, using tributyltin hydride or TTMSS as a radical mediator.

  5. Oligomeric rare-earth metal cluster complexes with endohedral transition metal atoms

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, Simon; Zimmermann, Sina; Brühmann, Matthias; Meyer, Eva; Rustige, Christian; Wolberg, Marike; Daub, Kathrin; Bell, Thomas; Meyer, Gerd, E-mail: gerd.meyer@uni-koeln.de

    2014-11-15

    Comproportionation reactions of rare-earth metal trihalides (RX{sub 3}) with the respective rare-earth metals (R) and transition metals (T) led to the formation of 22 oligomeric R cluster halides encapsulating T, in 19 cases for the first time. The structures of these compounds were determined by single-crystal X-ray diffraction and are composed of trimers ((T{sub 3}R{sub 11})X{sub 15}-type, P6{sub 3}/m), tetramers ((T{sub 4}R{sub 16})X{sub 28}(R{sub 4}) (P-43m), (T{sub 4}R{sub 16})X{sub 20} (P4{sub 2}/nnm), (T{sub 4}R{sub 16})X{sub 24}(RX{sub 3}){sub 4} (I4{sub 1}/a) and (T{sub 4}R{sub 16})X{sub 23} (C2/m) types of structure) and pentamers ((Ru{sub 5}La{sub 14}){sub 2}Br{sub 39}, Cc) of (TR{sub r}){sub n} (n=2–5) clusters. These oligomers are further enveloped by inner (X{sup i}) as well as outer (X{sup a}) halido ligands, which possess diverse functionalities and interconnect like oligomers through i–i, i–a and/or a–i bridges. The general features of the crystal structures for these new compounds are discussed and compared to literature entries as well as different structure types with oligomeric T centered R clusters. Dimers and tetramers originating from the aggregation of (TR{sub 6}) octahedra via common edges are more frequent than trimers and pentamers, in which the (TR{sub r}) clusters share common faces. - Graphical abstract: Rare earth-metal cluster complexes with endohedral transition metal atoms (TR{sub 6}) may connect via common edges or faces to form dimers, trimers, tetramers and pentamers of which the tetramers are the most prolific. Packing effects and electron counts play an important role. - Highlights: • Rare-earth metal cluster complexes encapsulate transition metal atoms. • Oligomers are built via connection of octahedral clusters via common edges or faces. • Dimers through pentamers with closed structures are known. • Tetramers including a tetrahedron of endohedral atoms are the most prolific.

  6. clusters

    Indian Academy of Sciences (India)

    2017-09-27

    Sep 27, 2017 ... Author for correspondence (zh4403701@126.com). MS received 15 ... lic clusters using density functional theory (DFT)-GGA of the DMOL3 package. ... In the process of geometric optimization, con- vergence thresholds ..... and Postgraduate Research & Practice Innovation Program of. Jiangsu Province ...

  7. clusters

    Indian Academy of Sciences (India)

    environmental as well as technical problems during fuel gas utilization. ... adsorption on some alloys of Pd, namely PdAu, PdAg ... ried out on small neutral and charged Au24,26,27, Cu,28 ... study of Zanti et al.29 on Pdn (n = 1–9) clusters.

  8. Cell surface clustering of Cadherin adhesion complex induced by antibody coated beads

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Cadherin receptors mediate cell-cell adhesion, signal transduction and assembly of cytoskeletons. How a single transmembrane molecule Cadherin can be involved in multiple functions through modulating its binding activities with many membrane adhesion molecules and cytoskeletal components is an unanswered question which can be elucidated by clues from bead experiments. Human lung cells expressing N-Cadherin were examined. After co-incubation with anti-N-Cadherin monoclonal antibody coated beads, cell surface clustering of N-Cadherin was induced. Immunofluorescent detection demonstrated that in addition to Cadherin, β-Catenin, α-Catenin, α-Actinin and Actin fluorescence also aggregated respectively at the membrane site of bead attachment. Myosin heavy chain (MHC), another major component of Actin cytoskeleton, did not aggregate at the membrane site of bead attachment. Adhesion unrelated protein Con A and polylysine conjugated beads did not induce the clustering of adhesion molecules. It is indicated that the Cadherin/Catenins/α-Actinin/Actin complex is formed at Cadherin mediated cell adherens junction; occupancy and cell surface clustering of Cadherin is crucial for the formation of Cadherin adhesion protein complexes.

  9. Young stellar population and star formation history ofW4 HII region/Cluster Complex

    Science.gov (United States)

    Panwar, Neelam

    2018-04-01

    The HII region/cluster complex has been a subject of numerous investigations to study the feedback effect of massive stars on their surroundings. Massive stars not only alter the morphology of the parental molecular clouds, but also influence star formation, circumstellar disks and the mass function of low-mass stars in their vicinity. However, most of the studies of low-mass stellar content of the HII regions are limited only to the nearby regions. We study the star formation in the W4 HII region using deep optical observations obtained with the archival data from Canada - France - Hawaii Telescope, Two-Micron All Sky Survey, Spitzer, Herschel and Chandra. We investigate the spatial distribution of young stellar objects in the region, their association with the remnant molecular clouds, and search for the clustering to establish the sites of recent star formation. Our analysis suggests that the influence of massive stars on circumstellar disks is significant only to thei! r immediate neighborhood. The spatial correlation of the young stars with the distribution of gas and dust of the complex indicate that the clusters would have formed in a large filamentary cloud. The observing facilities at the 3.6-m Devasthal Optical Telescope (DOT), providing high-resolution spectral and imaging capabilities, will fulfill the major objectives in the study of HII regions.

  10. Cluster-Expansion Model for Complex Quinary Alloys: Application to Alnico Permanent Magnets

    Science.gov (United States)

    Nguyen, Manh Cuong; Zhou, Lin; Tang, Wei; Kramer, Matthew J.; Anderson, Iver E.; Wang, Cai-Zhuang; Ho, Kai-Ming

    2017-11-01

    An accurate and transferable cluster-expansion model for complex quinary alloys is developed. Lattice Monte Carlo simulation enabled by this cluster-expansion model is used to investigate temperature-dependent atomic structure of alnico alloys, which are considered as promising high-performance non-rare-earth permanent-magnet materials for high-temperature applications. The results of the Monte Carlo simulations are consistent with available experimental data and provide useful insights into phase decomposition, selection, and chemical ordering in alnico. The simulations also reveal a previously unrecognized D 03 alloy phase. This phase is very rich in Ni and exhibits very weak magnetization. Manipulating the size and location of this phase provides a possible route to improve the magnetic properties of alnico, especially coercivity.

  11. Uncovering and testing the fuzzy clusters based on lumped Markov chain in complex network.

    Science.gov (United States)

    Jing, Fan; Jianbin, Xie; Jinlong, Wang; Jinshuai, Qu

    2013-01-01

    Identifying clusters, namely groups of nodes with comparatively strong internal connectivity, is a fundamental task for deeply understanding the structure and function of a network. By means of a lumped Markov chain model of a random walker, we propose two novel ways of inferring the lumped markov transition matrix. Furthermore, some useful results are proposed based on the analysis of the properties of the lumped Markov process. To find the best partition of complex networks, a novel framework including two algorithms for network partition based on the optimal lumped Markovian dynamics is derived to solve this problem. The algorithms are constructed to minimize the objective function under this framework. It is demonstrated by the simulation experiments that our algorithms can efficiently determine the probabilities with which a node belongs to different clusters during the learning process and naturally supports the fuzzy partition. Moreover, they are successfully applied to real-world network, including the social interactions between members of a karate club.

  12. Alternative synthetic route for the heterometallic CO-releasing [Sb@Rh12(CO27]3− icosahedral carbonyl cluster and synthesis of its new unsaturated [Sb@Rh12(CO24]4− and dimeric [{Sb@Rh12Sb(CO25}2Rh(CO2PPh3]7− derivatives

    Directory of Open Access Journals (Sweden)

    Cristina Femoni

    2016-10-01

    Full Text Available The hetero-metallic [Sb@Rh12(CO27]3− cluster has been known as for over three decades thanks to Vidal and co-workers, and represents the first example of an E-centered (E=heteroatom icosahedral rhodium carbonyl cluster. However, its synthesis required high temperature (140–160 °C and elevated CO pressure (400 atm. Applying the redox condensation method for cluster preparation, we herein report a new synthetic, high-yield route for preparing [Sb@Rh12(CO27]3− under much milder conditions of temperature and pressure. Notably, when the same synthesis was carried out under N2 instead of CO atmosphere, the new isostructural but unsaturated derivative [Sb@Rh12(CO24]4− was obtained, for which we report the full X-ray structural characterization. This species represents one of the few examples of an icosahedral cluster disobeying the electron-counting Wade-Mingos rules, possessing less than the expected 170 cluster valence electrons (CVEs. Judging from IR monitoring, the two species can be obtained one from the other by switching between N2 and CO atmosphere, making [Sb@Rh12(CO27]3− a spontaneous CO-releasing molecule. Finally, the study of the chemical reactivity of [Sb@Rh12(CO27]3− with PPh3 allowed us to obtain the new [{Sb@Rh12Sb(CO25}2Rh(CO2PPh3]7− dimeric compound, for which we herein report the full X-ray structural and 31P NMR analyses.

  13. CHEMICAL ABUNDANCES IN NGC 5053: A VERY METAL-POOR AND DYNAMICALLY COMPLEX GLOBULAR CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Boberg, Owen M.; Friel, Eileen D.; Vesperini, Enrico [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States)

    2015-05-10

    NGC 5053 provides a rich environment to test our understanding of the complex evolution of globular clusters (GCs). Recent studies have found that this cluster has interesting morphological features beyond the typical spherical distribution of GCs, suggesting that external tidal effects have played an important role in its evolution and current properties. Additionally, simulations have shown that NGC 5053 could be a likely candidate to belong to the Sagittarius dwarf galaxy (Sgr dSph) stream. Using the Wisconsin–Indiana–Yale–NOAO–Hydra multi-object spectrograph, we have collected high quality (signal-to-noise ratio ∼ 75–90), medium-resolution spectra for red giant branch stars in NGC 5053. Using these spectra we have measured the Fe, Ca, Ti, Ni, Ba, Na, and O abundances in the cluster. We measure an average cluster [Fe/H] abundance of −2.45 with a standard deviation of 0.04 dex, making NGC 5053 one of the most metal-poor GCs in the Milky Way (MW). The [Ca/Fe], [Ti/Fe], and [Ba/Fe] we measure are consistent with the abundances of MW halo stars at a similar metallicity, with alpha-enhanced ratios and slightly depleted [Ba/Fe]. The Na and O abundances show the Na–O anti-correlation found in most GCs. From our abundance analysis it appears that NGC 5053 is at least chemically similar to other GCs found in the MW. This does not, however, rule out NGC 5053 being associated with the Sgr dSph stream.

  14. Chemical Abundances in NGC 5053: A Very Metal-poor and Dynamically Complex Globular Cluster

    Science.gov (United States)

    Boberg, Owen M.; Friel, Eileen D.; Vesperini, Enrico

    2015-05-01

    NGC 5053 provides a rich environment to test our understanding of the complex evolution of globular clusters (GCs). Recent studies have found that this cluster has interesting morphological features beyond the typical spherical distribution of GCs, suggesting that external tidal effects have played an important role in its evolution and current properties. Additionally, simulations have shown that NGC 5053 could be a likely candidate to belong to the Sagittarius dwarf galaxy (Sgr dSph) stream. Using the Wisconsin-Indiana-Yale-NOAO-Hydra multi-object spectrograph, we have collected high quality (signal-to-noise ratio ˜ 75-90), medium-resolution spectra for red giant branch stars in NGC 5053. Using these spectra we have measured the Fe, Ca, Ti, Ni, Ba, Na, and O abundances in the cluster. We measure an average cluster [Fe/H] abundance of -2.45 with a standard deviation of 0.04 dex, making NGC 5053 one of the most metal-poor GCs in the Milky Way (MW). The [Ca/Fe], [Ti/Fe], and [Ba/Fe] we measure are consistent with the abundances of MW halo stars at a similar metallicity, with alpha-enhanced ratios and slightly depleted [Ba/Fe]. The Na and O abundances show the Na-O anti-correlation found in most GCs. From our abundance analysis it appears that NGC 5053 is at least chemically similar to other GCs found in the MW. This does not, however, rule out NGC 5053 being associated with the Sgr dSph stream.

  15. Lipid clustering correlates with membrane curvature as revealed by molecular simulations of complex lipid bilayers.

    Directory of Open Access Journals (Sweden)

    Heidi Koldsø

    2014-10-01

    Full Text Available Cell membranes are complex multicomponent systems, which are highly heterogeneous in the lipid distribution and composition. To date, most molecular simulations have focussed on relatively simple lipid compositions, helping to inform our understanding of in vitro experimental studies. Here we describe on simulations of complex asymmetric plasma membrane model, which contains seven different lipids species including the glycolipid GM3 in the outer leaflet and the anionic lipid, phosphatidylinositol 4,5-bisphophate (PIP2, in the inner leaflet. Plasma membrane models consisting of 1500 lipids and resembling the in vivo composition were constructed and simulations were run for 5 µs. In these simulations the most striking feature was the formation of nano-clusters of GM3 within the outer leaflet. In simulations of protein interactions within a plasma membrane model, GM3, PIP2, and cholesterol all formed favorable interactions with the model α-helical protein. A larger scale simulation of a model plasma membrane containing 6000 lipid molecules revealed correlations between curvature of the bilayer surface and clustering of lipid molecules. In particular, the concave (when viewed from the extracellular side regions of the bilayer surface were locally enriched in GM3. In summary, these simulations explore the nanoscale dynamics of model bilayers which mimic the in vivo lipid composition of mammalian plasma membranes, revealing emergent nanoscale membrane organization which may be coupled both to fluctuations in local membrane geometry and to interactions with proteins.

  16. Production of metal particles and clusters

    Science.gov (United States)

    Mcmanus, S. P.

    1982-01-01

    The feasibility of producing novel metals or metal clusters in a low gravity environment was studied. The production of coordinately unsaturated metal carbonyls by thermolysis or photolysis of stable metal carbonyls has the potential to generate novel catalysts by this technique. Laser irradiation of available metal carbonyls was investigated. It is found that laser induced decomposition of metal carbonyls is feasible for producing a variety of coordinately unsaturated species. Formation of clustered species does occur but is hampered by weak metal-metal bonds.

  17. Beyond alkyl transfer: Synthesis of main group metal (Mg, Ca, Zn) silyl and tris(oxazolinyl)borato complexes and their stoichiometric and catalytic reactions with borane Lewis acids and carbonyls

    Energy Technology Data Exchange (ETDEWEB)

    Lampland, Nicole Lynn [Iowa State Univ., Ames, IA (United States)

    2015-05-09

    Recently, the fundamental knowledge of main group metal chemistry has grown. This progress is crucial for the further development of main group metal compounds in silicon chemistry and catalysis and for advancing their applications as green alternatives to many rare earth and transition metal compounds. This thesis focuses on reactivity beyond the welldocumented alkyl-transfer applications for main group metals, and it highlights examples of reactions with Lewis acids and the reduction of carbonyls.

  18. Transition metal catalyzed carbonylation reactions carbonylative activation of C-X bonds

    CERN Document Server

    Beller, Matthias

    2014-01-01

    This book provides students and researchers in organic synthesis with a detailed discussion of carbonylation from the basics through to applications. It discusses the past, present and future of carbonylation reactions.

  19. Cluster as a Tool to Increase the Competitiveness and Innovative Activity of Enterprises of the Defense Industry Complex

    Directory of Open Access Journals (Sweden)

    Katrina B. Dobrova

    2017-01-01

    Full Text Available Purpose: the main goal of the publication is to make a comprehensive study of the possible application of the cluster approach to improve the competitiveness and innovation activity of enterprises of the defense industry complex.Methods: the methodology of the research is based on the collection and analysis of initial data and information, the article uses a systematic approach to the study of socio-economic processes and phenomena. The research is based on modern theory of competition, innovation, as well as the modern paradigm of cluster development of the economy. In preparing the study, practical materials from Corporation “Rostec”.Results: the article gives the notion of cluster, the prospects for the use of the cluster approach to enhance competitiveness and innovation enterprises of the military-industrial complex. It is noted that the activation of interaction with the “civil sector” is particularly relevant in the context of the reduction of the state defense order, and the theory and practice of cluster management offers a number of forms of cluster interaction between the enterprises of the defense industry and the civil sector. It is emphasized that the development of cluster mechanisms can solve a number of problems related to the insufficient financial stability of defense industry enterprises in the context of a reduction in the state defense order, low innovation activity and the lack of developed models of interaction with small innovative enterprises. Ultimately, the use of cluster mechanisms in the development of defense enterprises is intended to enhance the competitiveness of the complex, both nationally and globally. It is stated that the existing clusters are not able to fully solve a number of specific tasks related to the diversification of integrated defense industry structures. Attention is drawn to the fact that existing clusters are not able to fully solve a number of specific tasks related to the

  20. STAR CLUSTER COMPLEXES AND THE HOST GALAXY IN THREE H II GALAXIES: Mrk 36, UM 408, AND UM 461

    Energy Technology Data Exchange (ETDEWEB)

    Lagos, P. [Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Telles, E. [Observatorio Nacional, Rua Jose Cristino, 77, Rio de Janeiro 20921-400 (Brazil); Nigoche-Netro, A. [Instituto de Astrofisica de Andalucia (IAA), Glorieta de la Astronomia s/n, 18008 Granada (Spain); Carrasco, E. R., E-mail: plagos@astro.up.pt, E-mail: etelles@on.br, E-mail: nigoche@iaa.es, E-mail: rcarrasco@gemini.edu [Gemini Observatory/AURA, Southern Operations Center, Casilla 603, La Serena (Chile)

    2011-11-15

    We present a stellar population study of three H II galaxies (Mrk 36, UM 408, and UM 461) based on the analysis of new ground-based high-resolution near-infrared J, H, and K{sub p} broadband and Br{gamma} narrowband images obtained with Gemini/NIRI. We identify and determine the relative ages and masses of the elementary star clusters and/or star cluster complexes of the starburst regions in each of these galaxies by comparing the colors with evolutionary synthesis models that include the contribution of stellar continuum, nebular continuum, and emission lines. We found that the current star cluster formation efficiency in our sample of low-luminosity H II galaxies is {approx}10%. Therefore, most of the recent star formation is not in massive clusters. Our findings seem to indicate that the star formation mode in our sample of galaxies is clumpy, and that these complexes are formed by a few massive star clusters with masses {approx}>10{sup 4} M{sub Sun }. The age distribution of these star cluster complexes shows that the current burst started recently and likely simultaneously over short timescales in their host galaxies, triggered by some internal mechanism. Finally, the fraction of the total cluster mass with respect to the low surface brightness (or host galaxy) mass, considering our complete range in ages, is less than 1%.

  1. NEW CONSTRAINTS ON A COMPLEX RELATION BETWEEN GLOBULAR CLUSTER COLORS AND ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    Powalka, Mathieu; Lançon, Ariane [Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l’Université, F-67000 Strasbourg (France); Puzia, Thomas H.; Alamo-Martínez, Karla; Ángel, Simón [Institute of Astrophysics, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile); Peng, Eric W.; Lim, Sungsoon [Department of Astronomy, Peking University, Beijing 100871 (China); Schönebeck, Frederik; Grebel, Eva K. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany); Blakeslee, John P.; Côté, Patrick; Ferrarese, Laura; Gwyn, S. D. J. [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC V9E 2E7 (Canada); Cuillandre, Jean-Charles; Duc, Pierre-Alain [AIM Paris Saclay, CNRS/INSU, CEA/Irfu, Université Paris Diderot, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France); Durrell, Patrick [Department of Physics and Astronomy, Youngstown State University, One University Plaza, Youngstown, OH 44555 (United States); Guhathakurta, Puragra [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Kuntschner, Harald, E-mail: mathieu.powalka@astro.unistra.fr [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany); and others

    2016-09-20

    We present an analysis of high-quality photometry for globular clusters (GCs) in the Virgo cluster core region, based on data from the Next Generation Virgo Cluster Survey (NGVS) pilot field, and in the Milky Way (MW), based on Very Large Telescope/X-Shooter spectrophotometry. We find significant discrepancies in color–color diagrams between sub-samples from different environments, confirming that the environment has a strong influence on the integrated colors of GCs. GC color distributions along a single color are not sufficient to capture the differences we observe in color–color space. While the average photometric colors become bluer with increasing radial distance to the cD galaxy M87, we also find a relation between the environment and the slope and intercept of the color–color relations. A denser environment seems to produce a larger dynamic range in certain color indices. We argue that these results are not due solely to differential extinction, Initial Mass Function variations, calibration uncertainties, or overall age/metallicity variations. We therefore suggest that the relation between the environment and GC colors is, at least in part, due to chemical abundance variations, which affect stellar spectra and stellar evolution tracks. Our results demonstrate that stellar population diagnostics derived from model predictions which are calibrated on one particular sample of GCs may not be appropriate for all extragalactic GCs. These results advocate a more complex model of the assembly history of GC systems in massive galaxies that goes beyond the simple bimodality found in previous decades.

  2. NEW CONSTRAINTS ON A COMPLEX RELATION BETWEEN GLOBULAR CLUSTER COLORS AND ENVIRONMENT

    International Nuclear Information System (INIS)

    Powalka, Mathieu; Lançon, Ariane; Puzia, Thomas H.; Alamo-Martínez, Karla; Ángel, Simón; Peng, Eric W.; Lim, Sungsoon; Schönebeck, Frederik; Grebel, Eva K.; Blakeslee, John P.; Côté, Patrick; Ferrarese, Laura; Gwyn, S. D. J.; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Durrell, Patrick; Guhathakurta, Puragra; Kuntschner, Harald

    2016-01-01

    We present an analysis of high-quality photometry for globular clusters (GCs) in the Virgo cluster core region, based on data from the Next Generation Virgo Cluster Survey (NGVS) pilot field, and in the Milky Way (MW), based on Very Large Telescope/X-Shooter spectrophotometry. We find significant discrepancies in color–color diagrams between sub-samples from different environments, confirming that the environment has a strong influence on the integrated colors of GCs. GC color distributions along a single color are not sufficient to capture the differences we observe in color–color space. While the average photometric colors become bluer with increasing radial distance to the cD galaxy M87, we also find a relation between the environment and the slope and intercept of the color–color relations. A denser environment seems to produce a larger dynamic range in certain color indices. We argue that these results are not due solely to differential extinction, Initial Mass Function variations, calibration uncertainties, or overall age/metallicity variations. We therefore suggest that the relation between the environment and GC colors is, at least in part, due to chemical abundance variations, which affect stellar spectra and stellar evolution tracks. Our results demonstrate that stellar population diagnostics derived from model predictions which are calibrated on one particular sample of GCs may not be appropriate for all extragalactic GCs. These results advocate a more complex model of the assembly history of GC systems in massive galaxies that goes beyond the simple bimodality found in previous decades.

  3. Comparison of Degrees of Potential-Energy-Surface Anharmonicity for Complexes and Clusters with Hydrogen Bonds

    Science.gov (United States)

    Kozlovskaya, E. N.; Doroshenko, I. Yu.; Pogorelov, V. E.; Vaskivskyi, Ye. V.; Pitsevich, G. A.

    2018-01-01

    Previously calculated multidimensional potential-energy surfaces of the MeOH monomer and dimer, water dimer, malonaldehyde, formic acid dimer, free pyridine-N-oxide/trichloroacetic acid complex, and protonated water dimer were analyzed. The corresponding harmonic potential-energy surfaces near the global minima were constructed for series of clusters and complexes with hydrogen bonds of different strengths based on the behavior of the calculated multidimensional potential-energy surfaces. This enabled the introduction of an obvious anharmonicity parameter for the calculated potential-energy surfaces. The anharmonicity parameter was analyzed as functions of the size of the analyzed area near the energy minimum, the number of points over which energies were compared, and the dimensionality of the solved vibrational problem. Anharmonicity parameters for potential-energy surfaces in complexes with strong, medium, and weak H-bonds were calculated under identical conditions. The obtained anharmonicity parameters were compared with the corresponding diagonal anharmonicity constants for stretching vibrations of the bridging protons and the lengths of the hydrogen bridges.

  4. Studies of the charge instabilities in the complex nano-objects: clusters and bio-molecular systems

    International Nuclear Information System (INIS)

    Manil, B.

    2007-11-01

    For the last 6 years, my main research works focused on i) the Coulomb instabilities and the fragmentation processes of fullerenes and clusters of fullerenes ii) the stability and the reactivity of complex bio-molecular systems. Concerning the clusters of fullerenes, which are van der Waals type clusters, we have shown that the multiply charged species, obtained in collisions with slow highly charged ions, keep their structural properties but become very good electric conductor. In another hand, with the aim to understand the role of the biologic environment at the molecular scale in the irradiation damage of complex biomolecules, we have studied the charge stabilities of clusters of small biomolecules and the dissociation processes of larger nano-hydrated biomolecules. Theses studies have shown that first, specific molecular recognition mechanisms continue to exist in gas phase and secondly, a small and very simple biochemical environment is enough to change the dynamics of instabilities. (author)

  5. Hyperspectral clustering and unmixing for studying the ecology of state formation and complex societies

    Science.gov (United States)

    Kwong, Justin D.; Messinger, David W.; Middleton, William D.

    2009-08-01

    This project is an application of hyperspectral classification and unmixing in support of an ongoing archaeological study. The study region is the Oaxaca Valley located in the state of Oaxaca, Mexico on the southern coast. This was the birthplace of the Zapotec civilization which grew into a complex state level society. Hyperion imagery is being collected over a 30,000 km2 area. Classification maps of regions of interest are generated using K-means clustering and a novel algorithm called Gradient Flow. Gradient Flow departs from conventional stochastic or deterministic approaches, using graph theory to cluster spectral data. Spectral unmixing is conducted using the RIT developed algorithm Max-D to automatically find end members. Stepwise unmixing is performed to better model the data using the end members found be Max-D. Data are efficiently shared between imaging scientists and archaeologists using Google Earth to stream images over the internet rather than downloading them. The overall goal of the project is to provide archaeologists with useful information maps without having to interpret the raw data.

  6. The Sustainable Development of Industry Clusters: Emergent Knowledge Networks and Socio Complex Adaptive Systems

    Directory of Open Access Journals (Sweden)

    Susu Nousala

    2009-10-01

    Full Text Available In a highly competitive global economy the development of sustainable, innovative responses from Industry is now vital. Many industries globally need to respond rather than react to current economic climate through sustainable (economically and environmentally development. The steel industry is a critical player in the urban landscape. Like many industries, small, medium enterprises (SMEs are vital players within the steel industry supply chain. The Australian SME steel housing sector (based in rural and regional areas are still developing systemic capabilities with the aim of realizing its full potential. The question of an effective sustainable industry is much larger than any one player. This paper aims to present a proposed methodological approach for sustainable cluster development based on previous industry wide investigations. Through the lens of scalability of a socio complex adaptive system, SME development becomes arguably the most significant player with regards to industry cluster development. By starting with SME development it's possible to build an understanding of a simultaneous two layered approach, "bottom up – top down" whilst including a very diversified group.

  7. Hyperplane distance neighbor clustering based on local discriminant analysis for complex chemical processes monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chunhong; Xiao, Shaoqing; Gu, Xiaofeng [Jiangnan University, Wuxi (China)

    2014-11-15

    The collected training data often include both normal and faulty samples for complex chemical processes. However, some monitoring methods, such as partial least squares (PLS), principal component analysis (PCA), independent component analysis (ICA) and Fisher discriminant analysis (FDA), require fault-free data to build the normal operation model. These techniques are applicable after the preliminary step of data clustering is applied. We here propose a novel hyperplane distance neighbor clustering (HDNC) based on the local discriminant analysis (LDA) for chemical process monitoring. First, faulty samples are separated from normal ones using the HDNC method. Then, the optimal subspace for fault detection and classification can be obtained using the LDA approach. The proposed method takes the multimodality within the faulty data into account, and thus improves the capability of process monitoring significantly. The HDNC-LDA monitoring approach is applied to two simulation processes and then compared with the conventional FDA based on the K-nearest neighbor (KNN-FDA) method. The results obtained in two different scenarios demonstrate the superiority of the HDNC-LDA approach in terms of fault detection and classification accuracy.

  8. The contribution of cluster and discriminant analysis to the classification of complex aquifer systems.

    Science.gov (United States)

    Panagopoulos, G P; Angelopoulou, D; Tzirtzilakis, E E; Giannoulopoulos, P

    2016-10-01

    This paper presents an innovated method for the discrimination of groundwater samples in common groups representing the hydrogeological units from where they have been pumped. This method proved very efficient even in areas with complex hydrogeological regimes. The proposed method requires chemical analyses of water samples only for major ions, meaning that it is applicable to most of cases worldwide. Another benefit of the method is that it gives a further insight of the aquifer hydrogeochemistry as it provides the ions that are responsible for the discrimination of the group. The procedure begins with cluster analysis of the dataset in order to classify the samples in the corresponding hydrogeological unit. The feasibility of the method is proven from the fact that the samples of volcanic origin were separated into two different clusters, namely the lava units and the pyroclastic-ignimbritic aquifer. The second step is the discriminant analysis of the data which provides the functions that distinguish the groups from each other and the most significant variables that define the hydrochemical composition of the aquifer. The whole procedure was highly successful as the 94.7 % of the samples were classified to the correct aquifer system. Finally, the resulted functions can be safely used to categorize samples of either unknown or doubtful origin improving thus the quality and the size of existing hydrochemical databases.

  9. The Mystery of Globular Clusters: Uncovering the Complexities of Their Evolution

    Science.gov (United States)

    O'Malley, Erin Marie

    In recent years, evidence has grown for the existence of multiple stellar populations in globular clusters (GCs). However, questions remain regarding the nature of these populations. Photometric observations clearly show discrete populations while spectroscopic observations seem to show a continuous spread. This dissertation provides steps to better understanding GCs and the complexities associated with their evolution. Calibration of stellar evolution models at low metallicity is necessary for comparison to GCs. Accurate abundances of metal-poor subdwarfs are determined and used in this calibration. A Monte Carlo analysis is then performed in order to determine accurate distances, absolute ages, and integrated orbital trajectories for 24 GCs. These results are of critical importance as they not only incorporate the observational uncertainty, but also the uncertainty incurred by the models themselves. Lastly, high resolution spectra of three GCs (NGC 6681, NGC 6584 and NGC 7099) are obtained for a detailed abundance analysis of red giant branch stars. The high resolution and signal-to-noise achieved in these observations allows for the discovery of a statistically significant Na-O anticorrelation in all three clusters, the populations of which agree with those from photometric observations. Although we cannot determine precisely the nature of the polluters that were the predecessors to the enhanced populations, we do know that both s-process and r-process mechanisms contributed to the evolution and these results can be used to help constrain future models of GC polluter candidates.

  10. Hyperplane distance neighbor clustering based on local discriminant analysis for complex chemical processes monitoring

    International Nuclear Information System (INIS)

    Lu, Chunhong; Xiao, Shaoqing; Gu, Xiaofeng

    2014-01-01

    The collected training data often include both normal and faulty samples for complex chemical processes. However, some monitoring methods, such as partial least squares (PLS), principal component analysis (PCA), independent component analysis (ICA) and Fisher discriminant analysis (FDA), require fault-free data to build the normal operation model. These techniques are applicable after the preliminary step of data clustering is applied. We here propose a novel hyperplane distance neighbor clustering (HDNC) based on the local discriminant analysis (LDA) for chemical process monitoring. First, faulty samples are separated from normal ones using the HDNC method. Then, the optimal subspace for fault detection and classification can be obtained using the LDA approach. The proposed method takes the multimodality within the faulty data into account, and thus improves the capability of process monitoring significantly. The HDNC-LDA monitoring approach is applied to two simulation processes and then compared with the conventional FDA based on the K-nearest neighbor (KNN-FDA) method. The results obtained in two different scenarios demonstrate the superiority of the HDNC-LDA approach in terms of fault detection and classification accuracy

  11. Complexes of DNA bases and Watson-Crick base pairs with small neutral gold clusters.

    Science.gov (United States)

    Kryachko, E S; Remacle, F

    2005-12-08

    The nature of the DNA-gold interaction determines and differentiates the affinity of the nucleobases (adenine, thymine, guanine, and cytosine) to gold. Our preliminary computational study [Kryachko, E. S.; Remacle, F. Nano Lett. 2005, 5, 735] demonstrates that two major bonding factors govern this interaction: the anchoring, either of the Au-N or Au-O type, and the nonconventional N-H...Au hydrogen bonding. In this paper, we offer insight into the nature of nucleobase-gold interactions and provide a detailed characterization of their different facets, i.e., geometrical, energetic, and spectroscopic aspects; the gold cluster size and gold coordination effects; proton affinity; and deprotonation energy. We then investigate how the Watson-Crick DNA pairing patterns are modulated by the nucleobase-gold interaction. We do so in terms of the proton affinities and deprotonation energies of those proton acceptors and proton donors which are involved in the interbase hydrogen bondings. A variety of properties of the most stable Watson-Crick [A x T]-Au3 and [G x C]-Au3 hybridized complexes are described and compared with the isolated Watson-Crick A x T and G x C ones. It is shown that enlarging the gold cluster size to Au6 results in a rather short gold-gold bond in the Watson-Crick interbase region of the [G x C]-Au6 complex that bridges the G x C pair and thus leads to a significant strengthening of G x C pairing.

  12. MASSIVE STARS IN THE Cl 1813-178 CLUSTER: AN EPISODE OF MASSIVE STAR FORMATION IN THE W33 COMPLEX

    International Nuclear Information System (INIS)

    Messineo, Maria; Davies, Ben; Figer, Donald F.; Trombley, Christine; Kudritzki, R. P.; Valenti, Elena; Najarro, F.; Michael Rich, R.

    2011-01-01

    Young massive (M > 10 4 M sun ) stellar clusters are a good laboratory to study the evolution of massive stars. Only a dozen of such clusters are known in the Galaxy. Here, we report about a new young massive stellar cluster in the Milky Way. Near-infrared medium-resolution spectroscopy with UIST on the UKIRT telescope and NIRSPEC on the Keck telescope, and X-ray observations with the Chandra and XMM satellites, of the Cl 1813-178 cluster confirm a large number of massive stars. We detected 1 red supergiant, 2 Wolf-Rayet stars, 1 candidate luminous blue variable, 2 OIf, and 19 OB stars. Among the latter, twelve are likely supergiants, four giants, and the faintest three dwarf stars. We detected post-main-sequence stars with masses between 25 and 100 M sun . A population with age of 4-4.5 Myr and a mass of ∼10, 000 M sun can reproduce such a mixture of massive evolved stars. This massive stellar cluster is the first detection of a cluster in the W33 complex. Six supernova remnants and several other candidate clusters are found in the direction of the same complex.

  13. Structural oxidation state studies of the manganese cluster in the oxygen evolving complex of photosystem II

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Wenchuan [Univ. of California, Berkeley, CA (United States)

    1994-11-01

    X-ray absorption spectroscopy (XAS) was performed on Photosystem II (PSII)-enriched membranes prepared from spinach to explore: (1) the correlation between structure and magnetic spin state of the Mn cluster in the oxygen evolving complex (OEC) in the S2 state; and (2) the oxidation state changes of the Mn cluster in the flash-induced S-states. The structure of the Mn cluster in the S2 state with the g~4 electron paramagnetic resonance (EPR) signal (S2-g4 state) was compared with that in the S2 state with multiline signal (S2-MLS state) and the S1 state. The S2-g4 state has a higher XAS inflection point energy than that of the S1 state, indicating the oxidation of Mn in the advance from the S1 to the S2-g4 state. Differences in the edge shape and in the extended X-ray absorption fine structure (EXAFS) show that the structure of the Mn cluster in the S2-g4 state is different from that in the S2-MLS or the S1 state. In the S2-g4 state, the second shell of backscatterers from the Mn absorber contains two Mn-Mn distances of 2.73 Å and 2.85 Å. Very little distance disorder exists in the second shell of the S1 or S2-MLS states. The third shell of the S2-g4 state at about 3.3 Å also contains increased heterogeneity relative to that of the S2-MLS or the S1 state. Various S-states were prepared at room-temperature by saturating, single-turnover flashes. The flash-dependent oscillation in the amplitude of the MLS was used to characterize the S-state composition and to construct "pure" S-state Mn K-edge spectra. The edge position shifts to higher energy by 1.8 eV upon the S1 → S2 transition.

  14. CHIMERA: Top-down model for hierarchical, overlapping and directed cluster structures in directed and weighted complex networks

    Science.gov (United States)

    Franke, R.

    2016-11-01

    In many networks discovered in biology, medicine, neuroscience and other disciplines special properties like a certain degree distribution and hierarchical cluster structure (also called communities) can be observed as general organizing principles. Detecting the cluster structure of an unknown network promises to identify functional subdivisions, hierarchy and interactions on a mesoscale. It is not trivial choosing an appropriate detection algorithm because there are multiple network, cluster and algorithmic properties to be considered. Edges can be weighted and/or directed, clusters overlap or build a hierarchy in several ways. Algorithms differ not only in runtime, memory requirements but also in allowed network and cluster properties. They are based on a specific definition of what a cluster is, too. On the one hand, a comprehensive network creation model is needed to build a large variety of benchmark networks with different reasonable structures to compare algorithms. On the other hand, if a cluster structure is already known, it is desirable to separate effects of this structure from other network properties. This can be done with null model networks that mimic an observed cluster structure to improve statistics on other network features. A third important application is the general study of properties in networks with different cluster structures, possibly evolving over time. Currently there are good benchmark and creation models available. But what is left is a precise sandbox model to build hierarchical, overlapping and directed clusters for undirected or directed, binary or weighted complex random networks on basis of a sophisticated blueprint. This gap shall be closed by the model CHIMERA (Cluster Hierarchy Interconnection Model for Evaluation, Research and Analysis) which will be introduced and described here for the first time.

  15. Cation-Cation Complexes of Pentavalent Uranyl: From Disproportionation Intermediates to Stable Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Mougel, Victor; Horeglad, Pawel; Nocton, Gregory; Pecaut, Jacques; Mazzanti, Marinella [CEA, INAC, SCIB, Laboratoire de Reconnaissance Ionique et Chimie de Coordination, CEA-Grenoble, 38054 GRENOBLE, Cedex 09 (France)

    2010-07-01

    Three new cation cation complexes of pentavalent uranyl, stable with respect to the disproportionation reaction, have been prepared from the reaction of the precursor [(UO{sub 2}py{sub 5})-(KI{sub 2}py{sub 2})]{sub n} (1) with the Schiff base ligands salen{sup 2-}, acacen{sup 2-}, and salophen{sup 2-} (H{sub 2}salen N, N'-ethylene-bis(salicylidene-imine), H{sub 2}acacen=-N, N'-ethylenebis(acetylacetone-imine), H{sub 2}salophen=N, N'-phenylene-bis(salicylidene-imine)). The preparation of stable complexes requires a careful choice of counter ions and reaction conditions. Notably the reaction of 1 with salophen{sup 2-} in pyridine leads to immediate disproportionation, but in the presence of [18]crown-6 ([18]C-6) a stable complex forms. The solid-state structure of the four tetra-nuclear complexes ([UO{sub 2}-(acacen)]{sub 4}[{mu}{sub 8}-]{sub 2}[K([18]C-6)(py)]{sub 2}) (3) and ([UO{sub 2}(acacen)](4)[{mu}{sub 8}-]).2[K([222])(py)] (4) ([UO{sub 2}(salophen)](4)[{mu}{sub 8}-K]{sub 2}[mu(5)-KI]{sub 2}[(K([18]C-6)]).2 [K([18]C-6)-(thf){sub 2}].2I (5), and ([UO{sub 2}(salen)(4)][{mu}{sub 8}-Rb]{sub 2}[Rb([18]C-6)]{sub 2}) (9) ([222] = [222]cryptand, py =pyridine), presenting a T-shaped cation cation interaction has been determined by X-ray crystallographic studies. NMR spectroscopic and UV/Vis studies show that the tetra-nuclear structure is maintained in pyridine solution for the salen and acacen complexes. Stable mononuclear complexes of pentavalent uranyl are also obtained by reduction of the hexavalent uranyl Schiff base complexes with cobaltocene in pyridine in the absence of coordinating cations. The reactivity of the complex [U{sup V}O{sub 2}(salen)(py)][Cp*{sub 2}Co] with different alkali ions demonstrates the crucial effect of coordinating cations on the stability of cation cation complexes. The nature of the cation plays a key role in the preparation of stable cation cation complexes. Stable tetra-nuclear complexes form in the presence of K

  16. Adaptive capacity of geographical clusters: Complexity science and network theory approach

    Science.gov (United States)

    Albino, Vito; Carbonara, Nunzia; Giannoccaro, Ilaria

    This paper deals with the adaptive capacity of geographical clusters (GCs), that is a relevant topic in the literature. To address this topic, GC is considered as a complex adaptive system (CAS). Three theoretical propositions concerning the GC adaptive capacity are formulated by using complexity theory. First, we identify three main properties of CAS s that affect the adaptive capacity, namely the interconnectivity, the heterogeneity, and the level of control, and define how the value of these properties influence the adaptive capacity. Then, we associate these properties with specific GC characteristics so obtaining the key conditions of GCs that give them the adaptive capacity so assuring their competitive advantage. To test these theoretical propositions, a case study on two real GCs is carried out. The considered GCs are modeled as networks where firms are nodes and inter-firms relationships are links. Heterogeneity, interconnectivity, and level of control are considered as network properties and thus measured by using the methods of the network theory.

  17. Ruthenium and osmium carbonyl nitrosyl complexes: Matrix infrared spectra and density functional calculations for M(CO){sub 2}(NO){sub 2} and M(CO)(NO) (M = Ru, Os)

    Energy Technology Data Exchange (ETDEWEB)

    Song, Zhenjun [Department of Chemistry, Tongji University, Shanghai 200092 (China); Wang, Xuefeng, E-mail: xfwang@tongji.edu.cn [Department of Chemistry, Tongji University, Shanghai 200092 (China); Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Laser-ablated ruthenium or osmium atom reactions with CO and NO mixtures in solid argon. Black-Right-Pointing-Pointer Metal carbonyl nitrosyls including M(CO)(NO) and 18-electron configuration M(CO){sub 2}(NO){sub 2} molecules (M = Ru, Os). Black-Right-Pointing-Pointer The observed absorption bands of reaction products are identified by isotopic substitution and DFT calculations. Black-Right-Pointing-Pointer The bonding and reaction mechanism are discussed in detail. -- Abstract: Laser-ablated ruthenium or osmium atom reactions with CO and NO mixtures in solid argon produce unsaturated metal carbonyl nitrosyls including M(CO)(NO) and 18-electron configuration M(CO){sub 2}(NO){sub 2} molecules (M = Ru, Os). The observed absorption bands of reaction products are identified by isotopic substitution, isotopic ratios and isotopic distributions ({sup 13}CO, {sup 15}NO, and mixtures). DFT (B3LYP and BP86) vibrational fundamental calculations reproduce observed frequencies and isotopic shifts very well. The bonding and reaction mechanism are discussed.

  18. The Raman and vibronic activity of intermolecular vibrations in aromatic-containing complexes and clusters

    International Nuclear Information System (INIS)

    Maxton, P.M.; Schaeffer, M.W.; Ohline, S.M.; Kim, W.; Venturo, V.A.; Felker, P.M.

    1994-01-01

    Theoretical and experimental results pertaining to the excitation of intermolecular vibrations in the Raman and vibronic spectra of aromatic-containing, weakly bound complexes and clusters are reported. The theoretical analysis of intermolecular Raman activity is based on the assumption that the polarizability tensor of a weakly bound species is given by the sum of the polarizability tensors of its constituent monomers. The analysis shows that the van der Waals bending fundamentals in aromatic--rare gas complexes may be expected to be strongly Raman active. More generally, it predicts strong Raman activity for intermolecular vibrations that involve the libration or internal rotation of monomer moieties having appreciable permanent polarizability anisotropies. The vibronic activity of intermolecular vibrations in aromatic-rare gas complexes is analyzed under the assumption that every vibronic band gains its strength from an aromatic-localized transition. It is found that intermolecular vibrational excitations can accompany aromatic-localized vibronic excitations by the usual Franck--Condon mechanism or by a mechanism dependent on the librational amplitude of the aromatic moiety during the course of the pertinent intermolecular vibration. The latter mechanism can impart appreciable intensity to bands that are forbidden by rigid-molecule symmetry selection rules. The applicability of such rules is therefore called into question. Finally, experimental spectra of intermolecular transitions, obtained by mass-selective, ionization-detected stimulated Raman spectroscopies, are reported for benzene--X (X=Ar, --Ar 2 , N 2 , HCl, CO 2 , and --fluorene), fluorobenzene--Ar and --Kr, aniline--Ar, and fluorene--Ar and --Ar 2 . The results support the conclusions of the theoretical analyses and provide further evidence for the value of Raman methods in characterizing intermolecular vibrational level structures

  19. A Chemical Composition Survey of the Iron-complex Globular Cluster NGC 6273 (M19)

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Christian I.; Caldwell, Nelson [Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, MS-15, Cambridge, MA 02138 (United States); Rich, R. Michael [Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States); Mateo, Mario [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Bailey, John I. III [Leiden Observatory, Leiden University, P.O. Box 9513, 2300RA Leiden (Netherlands); Clarkson, William I. [Department of Natural Sciences, University of Michigan–Dearborn, 4901 Evergreen Road, Dearborn, MI 48128 (United States); Olszewski, Edward W. [Steward Observatory, The University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Walker, Matthew G., E-mail: cjohnson@cfa.harvard.edu, E-mail: ncaldwell@cfa.harvard.edu, E-mail: rmr@astro.ucla.edu, E-mail: mmateo@umich.edu, E-mail: baileyji@strw.leidenuniv.nl, E-mail: wiclarks@umich.edu, E-mail: eolszewski@as.arizona.edu, E-mail: mgwalker@andrew.cmu.edu [McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)

    2017-02-20

    Recent observations have shown that a growing number of the most massive Galactic globular clusters contain multiple populations of stars with different [Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been recognized as a member of this “iron-complex” cluster class, and we provide here a chemical and kinematic analysis of >300 red giant branch and asymptotic giant branch member stars using high-resolution spectra obtained with the Magellan –M2FS and VLT–FLAMES instruments. Multiple lines of evidence indicate that NGC 6273 possesses an intrinsic metallicity spread that ranges from about [Fe/H] = −2 to −1 dex, and may include at least three populations with different [Fe/H] values. The three populations identified here contain separate first (Na/Al-poor) and second (Na/Al-rich) generation stars, but a Mg–Al anti-correlation may only be present in stars with [Fe/H] ≳ −1.65. The strong correlation between [La/Eu] and [Fe/H] suggests that the s-process must have dominated the heavy element enrichment at higher metallicities. A small group of stars with low [ α /Fe] is identified and may have been accreted from a former surrounding field star population. The cluster’s large abundance variations are coupled with a complex, extended, and multimodal blue horizontal branch (HB). The HB morphology and chemical abundances suggest that NGC 6273 may have an origin that is similar to ω Cen and M54.

  20. Towards a methodology for cluster searching to provide conceptual and contextual "richness" for systematic reviews of complex interventions: case study (CLUSTER).

    Science.gov (United States)

    Booth, Andrew; Harris, Janet; Croot, Elizabeth; Springett, Jane; Campbell, Fiona; Wilkins, Emma

    2013-09-28

    Systematic review methodologies can be harnessed to help researchers to understand and explain how complex interventions may work. Typically, when reviewing complex interventions, a review team will seek to understand the theories that underpin an intervention and the specific context for that intervention. A single published report from a research project does not typically contain this required level of detail. A review team may find it more useful to examine a "study cluster"; a group of related papers that explore and explain various features of a single project and thus supply necessary detail relating to theory and/or context.We sought to conduct a preliminary investigation, from a single case study review, of techniques required to identify a cluster of related research reports, to document the yield from such methods, and to outline a systematic methodology for cluster searching. In a systematic review of community engagement we identified a relevant project - the Gay Men's Task Force. From a single "key pearl citation" we conducted a series of related searches to find contextually or theoretically proximate documents. We followed up Citations, traced Lead authors, identified Unpublished materials, searched Google Scholar, tracked Theories, undertook ancestry searching for Early examples and followed up Related projects (embodied in the CLUSTER mnemonic). Our structured, formalised procedure for cluster searching identified useful reports that are not typically identified from topic-based searches on bibliographic databases. Items previously rejected by an initial sift were subsequently found to inform our understanding of underpinning theory (for example Diffusion of Innovations Theory), context or both. Relevant material included book chapters, a Web-based process evaluation, and peer reviewed reports of projects sharing a common ancestry. We used these reports to understand the context for the intervention and to explore explanations for its relative

  1. Cluster approach to realization of innovation development strategy for the agroindustrial complex of the region

    Directory of Open Access Journals (Sweden)

    Valentina Aleksandrovna Kundius

    2011-12-01

    Full Text Available This paper reviews cluster approach as an innovative management technology for the regional economy. The results of studying the theory and practice of clustering of the regional economy, the formation of agribusiness and food clusters in agribusiness are presented. Basic features and operation of the cluster systems are revealed and distinguished from other forms of cooperative and economic interactions between small and big business features, motivational components of integration into clusters. On the basis of scientific propositions, a model of regional economic clusters is formulated; specific territorial distribution and level of aggregation of clusters in the agricultural sector were distinguished. It is proposed to refer agroindustrial clusters to the clusters that represent the associations of organization of various fields in a single reproduction cycle from raw material to finished products sales including all stages of reproduction on the basis of innovation and investment activity. A structuring work on principles of agro-clusters was held, sustainable competitive advantage and the formation mechanisms of the development of agro-industrial clusters have been grounded.

  2. Electron-Poor Polar Intermetallics: Complex Structures, Novel Clusters, and Intriguing Bonding with Pronounced Electron Delocalization.

    Science.gov (United States)

    Lin, Qisheng; Miller, Gordon J

    2018-01-16

    complexity can be realized by small amounts of Li replacing Zn atoms in the parent binary compounds CaZn 2 , CaZn 3 , and CaZn 5 ; their phase formation and bonding schemes can be rationalized by Fermi surface-Brillouin zone interactions between nearly free-electron states. "Cation-rich", electron-poor polar intermetallics have emerged using rare earth metals as the electropositive ("cationic") component together metal/metalloid clusters that mimic the backbones of aromatic hydrocarbon molecules, which give evidence of extensive electronic delocalization and multicenter bonding. Thus, we can identify three distinct, valence electron-poor, polar intermetallic systems that have yielded unprecedented phases adopting novel structures containing complex clusters and intriguing bonding characteristics. In this Account, we summarize our recent specific progress in the developments of novel Au-rich BaAl 4 -type related structures, shown in the "gold-rich grid", lithiation-modulated Ca-Li-Zn phases stabilized by different bonding characteristics, and rare earth-rich polar intermetallics containing unprecedented hydrocarbon-like planar Co-Ge metal clusters and pronounced delocalized multicenter bonding. We will focus mainly on novel structural motifs, bonding analyses, and the role of valence electrons for phase stability.

  3. Tribological coatings for complex mechanical elements produced by supersonic cluster beam deposition of metal dichalcogenide nanoparticles

    Science.gov (United States)

    Piazzoni, C.; Buttery, M.; Hampson, M. R.; Roberts, E. W.; Ducati, C.; Lenardi, C.; Cavaliere, F.; Piseri, P.; Milani, P.

    2015-07-01

    Fullerene-like MoS2 and WS2 nanoparticles can be used as building blocks for the fabrication of fluid and solid lubricants. Metal dichalcogenide films have a very low friction coefficient in vacuum, therefore they have mostly been used as solid lubricants in space and vacuum applications. Unfortunately, their use is significantly hampered by the fact that in the presence of humidity, oxygen and moisture, the low-friction properties of these materials rapidly degrade due to oxidation. The use of closed-cage MoS2 and WS2 nanoparticles may eliminate this problem, although the fabrication of lubricant thin films starting from dichalcogenide nanoparticles is, to date, a difficult task. Here we demonstrate the use of supersonic cluster beam deposition for the coating of complex mechanical elements (angular contact ball bearings) with nanostructured MoS2 and WS2 thin films. We report structural and tribological characterization of the coatings in view of the optimization of tribological performances for aerospace applications.

  4. Complex Structure of Galaxy Cluster Abell 1689: Evidence for a Merger from X-Ray Data?

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, K

    2004-01-29

    Abell 1689 is a galaxy cluster at z = 0:183 where previous measurements of its mass using various techniques gave discrepant results. We present a new detailed measurement of the mass with the data based on X-ray observations with the European Photon Imaging Camera aboard the XMM-Newton Observatory, determined by using an unparameterized deprojection technique. Fitting the total mass profile to a Navarro-Frenk-White model yields halo concentration c = 7.2{sub -2.4}{sup +1.6} and r{sub 200} = 1.13 {+-} 0.21 h{sup -1} Mpc, corresponding to a mass which is less than half of what is found from gravitational lensing. Adding to the evidence of substructure from optical observations, X-ray analysis shows a highly asymmetric temperature profile and a non-uniform redshift distribution implying large scale relative motion of the gas. A lower than expected gas mass fraction f{sub gas} = 0.072 {+-} 0.008 (for a flat {Lambda}CDM cosmology) suggests a complex spatial and/or dynamical structure. We also find no signs of any additional absorbing component previously reported on the basis of the Chandra data, confirming the XMM low energy response using data from ROSAT.

  5. The E. coli monothiol glutaredoxin GrxD forms homodimeric and heterodimeric FeS cluster containing complexes.

    Science.gov (United States)

    Yeung, N; Gold, B; Liu, N L; Prathapam, R; Sterling, H J; Willams, E R; Butland, G

    2011-10-18

    Monothiol glutaredoxins (mono-Grx) represent a highly evolutionarily conserved class of proteins present in organisms ranging from prokaryotes to humans. Mono-Grxs have been implicated in iron sulfur (FeS) cluster biosynthesis as potential scaffold proteins and in iron homeostasis via an FeS-containing complex with Fra2p (homologue of E. coli BolA) in yeast and are linked to signal transduction in mammalian systems. However, the function of the mono-Grx in prokaryotes and the nature of an interaction with BolA-like proteins have not been established. Recent genome-wide screens for E. coli genetic interactions reported the synthetic lethality (combination of mutations leading to cell death; mutation of only one of these genes does not) of a grxD mutation when combined with strains defective in FeS cluster biosynthesis (isc operon) functions [Butland, G., et al. (2008) Nature Methods 5, 789-795]. These data connected the only E. coli mono-Grx, GrxD to a potential role in FeS cluster biosynthesis. We investigated GrxD to uncover the molecular basis of this synthetic lethality and observed that GrxD can form FeS-bound homodimeric and BolA containing heterodimeric complexes. These complexes display substantially different spectroscopic and functional properties, including the ability to act as scaffold proteins for intact FeS cluster transfer to the model [2Fe-2S] acceptor protein E. coli apo-ferredoxin (Fdx), with the homodimer being significantly more efficient. In this work, we functionally dissect the potential cellular roles of GrxD as a component of both homodimeric and heterodimeric complexes to ultimately uncover if either of these complexes performs functions linked to FeS cluster biosynthesis. © 2011 American Chemical Society

  6. Predicting protein complexes from weighted protein-protein interaction graphs with a novel unsupervised methodology: Evolutionary enhanced Markov clustering.

    Science.gov (United States)

    Theofilatos, Konstantinos; Pavlopoulou, Niki; Papasavvas, Christoforos; Likothanassis, Spiros; Dimitrakopoulos, Christos; Georgopoulos, Efstratios; Moschopoulos, Charalampos; Mavroudi, Seferina

    2015-03-01

    Proteins are considered to be the most important individual components of biological systems and they combine to form physical protein complexes which are responsible for certain molecular functions. Despite the large availability of protein-protein interaction (PPI) information, not much information is available about protein complexes. Experimental methods are limited in terms of time, efficiency, cost and performance constraints. Existing computational methods have provided encouraging preliminary results, but they phase certain disadvantages as they require parameter tuning, some of them cannot handle weighted PPI data and others do not allow a protein to participate in more than one protein complex. In the present paper, we propose a new fully unsupervised methodology for predicting protein complexes from weighted PPI graphs. The proposed methodology is called evolutionary enhanced Markov clustering (EE-MC) and it is a hybrid combination of an adaptive evolutionary algorithm and a state-of-the-art clustering algorithm named enhanced Markov clustering. EE-MC was compared with state-of-the-art methodologies when applied to datasets from the human and the yeast Saccharomyces cerevisiae organisms. Using public available datasets, EE-MC outperformed existing methodologies (in some datasets the separation metric was increased by 10-20%). Moreover, when applied to new human datasets its performance was encouraging in the prediction of protein complexes which consist of proteins with high functional similarity. In specific, 5737 protein complexes were predicted and 72.58% of them are enriched for at least one gene ontology (GO) function term. EE-MC is by design able to overcome intrinsic limitations of existing methodologies such as their inability to handle weighted PPI networks, their constraint to assign every protein in exactly one cluster and the difficulties they face concerning the parameter tuning. This fact was experimentally validated and moreover, new

  7. FRONTIER FIELDS CLUSTERS: DEEP CHANDRA OBSERVATIONS OF THE COMPLEX MERGER MACS J1149.6+2223

    Energy Technology Data Exchange (ETDEWEB)

    Ogrean, G. A.; Weeren, R. J. van; Jones, C.; Forman, W.; Andrade-Santos, F.; Murray, S. S.; Nulsen, P.; Bulbul, E.; Kraft, R.; Randall, S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Dawson, W. A. [Lawrence Livermore National Lab, 7000 East Avenue, Livermore, CA 94550 (United States); Golovich, N. [University of California, One Shields Avenue, Davis, CA 95616 (United States); Roediger, E. [Astronomy and Astrophysics Section, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Zitrin, A.; Sayers, J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Goulding, A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Umetsu, K. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Mroczkowski, T. [U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Bonafede, A. [Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany); Churazov, E., E-mail: gogrean@cfa.harvard.edu [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741, Garching (Germany); and others

    2016-03-10

    The Hubble Space Telescope Frontier Fields cluster MACS J1149.6+2223 is one of the most complex merging clusters, believed to consist of four dark matter halos. We present results from deep (365 ks) Chandra observations of the cluster, which reveal the most distant cold front (z  =  0.544) discovered to date. In the cluster outskirts, we also detect hints of a surface brightness edge that could be the bow shock preceding the cold front. The substructure analysis of the cluster identified several components with large relative radial velocities, thus indicating that at least some collisions occur almost along the line of sight. The inclination of the mergers with respect to the plane of the sky poses significant observational challenges at X-ray wavelengths. MACS J1149.6+2223 possibly hosts a steep-spectrum radio halo. If the steepness of the radio halo is confirmed, then the radio spectrum, combined with the relatively regular ICM morphology, could indicate that MACS J1149.6+2223 is an old merging cluster.

  8. Selective transformation of carbonyl ligands to organic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, A.R.

    1992-05-12

    Studies on the carbonylation of ({eta}{sup 5}-indenyl)(L)(CO)Ru-R complexes (L = CO, PPh{sub 3}; R = CH{sub 2}OMe, CH{sub 3}) have been completed. Particularly noteworthy is that the methoxymethyl complexes readily transform to their acyl derivatives under mild conditions that leave their iron congeners inert towards CO. Surprisingly, even ({eta}{sup 5}-indenyl)(PPh{sub 3}){sub 2}Ru-CH{sub 3} carbonylates and gives ({eta}{sup 5}-indenyl)(PPh{sub 3})(CO)Ru-C(O)CH{sub 3}. Mechanistic studies on the non catalyzed'' hydrosilation of the manganese acyls (CO){sub 5}Mn-C(O)CH{sub 2}R (R = H, OCH{sub 3}, CH{sub 3}) with Et{sub 3}SiH and of cobalt acetyls (CO){sub 3}(PR{sub 3})CoC(O)CH{sub 3} with several monohydrosilanes have been completed. The cobalt acetyls cleanly give ethoxysilanes (not acetaldehyde), and the manganese acyls provide {alpha}-siloxyvinyl complexes Z-(CO){sub 5}Mn-C(OSiEt{sub 3})=CHR (R = H, CH{sub 3}, OCH{sub 3}). Carbonylation and protolytic cleavage of the latter generate pyruvoyl complexes (CO){sub 5}Mn-COCOR (R = CH{sub 3}, CH{sub 2}CH{sub 3}), formally the products of net double carbonylation'' sequences. Studies in progress are concerned with how manganese complexes as diverse as (CO){sub 5}Mn-Y (Y = C(O)R, R, BR - but not SiMe{sub 3} or Mn(CO){sub 5}) and ({eta}{sup 3}-C{sub 3}H{sub 5})Mn(CO){sub 2}L (but not CpMn(CO){sub 3} or CpMn(CO){sub 2}({eta}{sup 2}HSiR{sub 3})) function as efficient hydrosilation catalysts towards Cp(CO){sub 2}FeC(O)CH{sub 3}, for example. These reactions cleanly afford fully characterized {alpha}-siloxyethyl complexes Fp-CH(OSiR{sub 3})CH{sub 3} under conditions where typically Rh(1) hydrosilation catalysts are inactive. Several of these manganese complexes also catalytically hydrosilate organic esters, including lactones, to their ethers R-CH{sub 2}OR; these novel ester reductions occur quantitatively at room temperature and appear to be general in scope.

  9. Complex open-framework germanate built by 8-coordinated Ge 10 clusters

    KAUST Repository

    Yue, Huijuan; Peskov, Maxim; Sun, Junliang; Zou, Xiaodong

    2012-01-01

    cluster building units can be concluded. The framework of SU-67 is based on an elaborate topological pattern of connected Ge 10 clusters forming intersecting 10- and 11-ring channels and has a low framework density (12.4 Ge atoms per 1000 ̊ 3). We have

  10. Electronic Structure of Transition Metal Clusters, Actinide Complexes and Their Reactivities

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan Balasubramanian

    2009-07-18

    methods with all-electron Douglas-Kroll relativistic methods. We have the capabilities for computing full CI extrapolations including spin-orbit effects and several one-electron properties and electron density maps including spin-orbit effects. We are continuously collaborating with several experimental groups around the country and at National Labs to carry out computational studies on the DOE-BES funded projects. The past work in the last 3 years was primarily motivated and driven by the concurrent or recent experimental studies on these systems. We were thus significantly benefited by coordinating our computational efforts with experimental studies. The interaction between theory and experiment has resulted in some unique and exciting opportunities. For example, for the very first time ever, the upper spin-orbit component of a heavy trimer such as Au{sub 3} was experimentally observed as a result of our accurate computational study on the upper electronic states of gold trimer. Likewise for the first time AuH{sub 2} could be observed and interpreted clearly due to our computed potential energy surfaces that revealed the existence of a large barrier to convert the isolated AuH{sub 2} back to Au and H{sub 2}. We have also worked on yet to be observed systems and have made predictions for future experiments. We have computed the spectroscopic and thermodynamic properties of transition metal carbides transition metal clusters and compared our electronic states to the anion photodetachment spectra of Lai Sheng Wang. Prof Mike Morse and coworkers(funded also by DOE-BES) and Prof Stimle and coworkers(also funded by DOE-BES) are working on the spectroscopic properties of transition metal carbides and nitrides. Our predictions on the excited states of transition metal clusters such as Hf{sub 3}, Nb{sub 2}{sup +} etc., have been confirmed experimentally by Prof. Lombardi and coworkers using resonance Raman spectroscopy. We have also been studying larger complexes critical to the

  11. Electronic Structure of Transition Metal Clusters, Actinide Complexes and Their Reactivities

    International Nuclear Information System (INIS)

    Balasubramanian, Krishnan

    2009-01-01

    methods with all-electron Douglas-Kroll relativistic methods. We have the capabilities for computing full CI extrapolations including spin-orbit effects and several one-electron properties and electron density maps including spin-orbit effects. We are continuously collaborating with several experimental groups around the country and at National Labs to carry out computational studies on the DOE-BES funded projects. The past work in the last 3 years was primarily motivated and driven by the concurrent or recent experimental studies on these systems. We were thus significantly benefited by coordinating our computational efforts with experimental studies. The interaction between theory and experiment has resulted in some unique and exciting opportunities. For example, for the very first time ever, the upper spin-orbit component of a heavy trimer such as Au 3 was experimentally observed as a result of our accurate computational study on the upper electronic states of gold trimer. Likewise for the first time AuH 2 could be observed and interpreted clearly due to our computed potential energy surfaces that revealed the existence of a large barrier to convert the isolated AuH 2 back to Au and H 2 . We have also worked on yet to be observed systems and have made predictions for future experiments. We have computed the spectroscopic and thermodynamic properties of transition metal carbides transition metal clusters and compared our electronic states to the anion photodetachment spectra of Lai Sheng Wang. Prof Mike Morse and coworkers(funded also by DOE-BES) and Prof Stimle and coworkers(also funded by DOE-BES) are working on the spectroscopic properties of transition metal carbides and nitrides. Our predictions on the excited states of transition metal clusters such as Hf 3 , Nb 2 + etc., have been confirmed experimentally by Prof. Lombardi and coworkers using resonance Raman spectroscopy. We have also been studying larger complexes critical to the environmental management of high

  12. Metal Sulfide Cluster Complexes and their Biogeochemical Importance in the Environment

    International Nuclear Information System (INIS)

    Luther, George W.; Rickard, David T.

    2005-01-01

    Aqueous clusters of FeS, ZnS and CuS constitute a major fraction of the dissolved metal load in anoxic oceanic, sedimentary, freshwater and deep ocean vent environments. Their ubiquity explains how metals are transported in anoxic environmental systems. Thermodynamic and kinetic considerations show that they have high stability in oxic aqueous environments, and are also a significant fraction of the total metal load in oxic river waters. Molecular modeling indicates that the clusters are very similar to the basic structural elements of the first condensed phase forming from aqueous solutions in the Fe-S, Zn-S and Cu-S systems. The structure of the first condensed phase is determined by the structure of the cluster in solution. This provides an alternative explanation of Ostwald's Rule, where the most soluble, metastable phases form before the stable phases. For example, in the case of FeS, we showed that the first condensed phase is nanoparticulate, metastable mackinawite with a particle size of 2 nm consisting of about 150 FeS subunits, representing the end of a continuum between aqueous FeS clusters and condensed material. These metal sulfide clusters and nanoparticles are significant in biogeochemistry. Metal sulfide clusters reduce sulfide and metal toxicity and help drive ecology. FeS cluster formation drives vent ecology and AgS cluster formation detoxifies Ag in Daphnia magna neonates. We also note a new reaction between FeS and DNA and discuss the potential role of FeS clusters in denaturing DNA

  13. Glucosinolates and isothiocyanates from broccoliseed extractsuppressproteinglycationand carbonylation

    Directory of Open Access Journals (Sweden)

    Marina Hirano,

    2018-01-01

    Full Text Available Background: Glucosinolates from brassica plants are hydrolyzed by internal or salivary myrosinase to produce isothiocyanates. Glucoraphanin, a major glucosinolate in broccoli, is hydrolyzed to sulforaphane (SFN, which exhibits antitumor and detoxification activities. Regarding the influence of broccoli and its constituents on the skin, a few studies have reported anti-inflammatory and antioxidant effects. Recently, advanced glycation end products (AGEs and carbonyl proteins have been reported to accelerate skin aging. Objective: We evaluated the effects of broccoli seed extract (BSE and glucosinolates on protein glycation and carbonylation in vitro. Methods: To evaluate the effects of BSE and its constituents, protein glycation and carbonylation were induced by mixing fructose with bovine serum albumin (BSA and then measuring production of AGEs, fructosamine, and carbonyl proteins (CP. Production of CP after mixing fatty acids with BSA was also assessed. Furthermore, the effect of BSE and its constituents on CP production by human fibroblasts (TIG103 was examined. Results: BSE suppressed the production of AGEs, fructosamine, and CP after mixing fructose and BSA. BSE also suppressed production of CP when oxidized linoleic acid was mixed with BSA. Isothiocyanates, including SFN and iberin, suppressed fructose-based CP production, but SFN had no effect on CP production stimulated by oxidized linoleic acid. In contrast, glucosinolates from BSE did not suppress fructose-based CP production, but suppressed CP production due to oxidized linoleic acid. Among the glucosinolates in BSE, glucoberteroin showed the strongest suppression of CP production. CP production in fibroblasts was also suppressed by glucosinolates, including glucoiberin and glucoberteroin. Conclusions: BSE demonstrated anti-glycation and anti-carbonylation effects on protein reactions with fructose and oxidized fatty acids. Isothiocyanates suppressed protein carbonylation induced by

  14. The Complexities of Implementing Cluster Supply Chain - Case Study of JCH

    Science.gov (United States)

    Xue, Xiao; Zhang, Jibiao; Wang, Yang

    As a new type of management pattern, "cluster supply chain" (CSC) can help SMEs to face the global challenges through all kinds of collaboration. However, a major challenge in implementing CSC is the gap between theory and practice in the field. In an effort to provide a better understanding of this emerging phenomenon, this paper presents the implementation process of CSC in the context of JingCheng Mechanical & Electrical Holding co., ltd.(JCH) as a case study. The cast study of JCH suggests that the key problems in the practice of cluster supply chain: How do small firms use cluster supply chain? Only after we clarify the problem, the actual construction and operation of cluster supply chain does show successful results as it should be.

  15. Spatiotemporal distribution of carbonyl compounds in China

    International Nuclear Information System (INIS)

    Ho, K.F.; Ho, Steven Sai Hang; Huang, R.-J.; Dai, W.T.; Cao, J.J.; Tian, Linwei; Deng, W.J.

    2015-01-01

    A sampling campaign was carried out at nine Chinese cities in 2010/2011. Fifteen monocarbonyls (C#= 1–9) were quantified. Temperature is the rate-determining factor of the summertime carbonyl levels. The carbonyl emissions in winter are mainly driven by the primary anthropogenic sources like automobile. A molar ratio of propionaldehyde to nonaldehyde is a barometer of the impact of atmospheric vegetation emission which suggesting that strong vegetation emissions exist in summer and high propionaldehyde abundance is caused by fossil fuel combustion in winter. Potential health risk assessment of formaldehyde and acetaldehyde was conducted and the highest cumulative risks were observed at Chengdu in summer and Wuhan in winter. Because of the strong photochemical reaction and large amount of anthropogenic emissions, high concentrations of carbonyl compounds were observed in Chengdu. The use of ethanol-blended gasoline in Wuhan is the key reason of acetaldehyde emission and action should be taken to avoid potential health risks. - Highlights: • A national wide survey of ambient carbonyl compounds were conducted in China. • Using ethanol-blended gasoline can lead to higher cancer risks. • High concentrations of HMW carbonyls (C6, C7, C8 and C9) were observed in all cities. • HMW carbonyls (C6–C9) species show a very consistent seasonal variation. • C 3 /C 9 acts as an indicator for the impact of vegetation emission in the atmosphere. - Capsule abstract: Strong vegetation emission occurs in summer atmosphere and high acetaldehyde emission due to ethanol-blended gasoline consumption in 9 Chinese cities is discouraged

  16. {Ni4O4} Cluster Complex to Enhance the Reductive Photocurrent Response on Silicon Nanowire Photocathodes

    Directory of Open Access Journals (Sweden)

    Yatin J. Mange

    2017-02-01

    Full Text Available Metal organic {Ni4O4} clusters, known oxidation catalysts, have been shown to provide a valuable route in increasing the photocurrent response on silicon nanowire (SiNW photocathodes. {Ni4O4} clusters have been paired with SiNWs to form a new photocathode composite for water splitting. Under AM1.5 conditions, the combination of {Ni4O4} clusters with SiNWs gave a current density of −16 mA/cm2, which corresponds to an increase in current density of 60% when compared to bare SiNWs. The composite electrode was fully characterised and shown to be an efficient and stable photocathode for water splitting.

  17. Cluster-cluster clustering

    International Nuclear Information System (INIS)

    Barnes, J.; Dekel, A.; Efstathiou, G.; Frenk, C.S.; Yale Univ., New Haven, CT; California Univ., Santa Barbara; Cambridge Univ., England; Sussex Univ., Brighton, England)

    1985-01-01

    The cluster correlation function xi sub c(r) is compared with the particle correlation function, xi(r) in cosmological N-body simulations with a wide range of initial conditions. The experiments include scale-free initial conditions, pancake models with a coherence length in the initial density field, and hybrid models. Three N-body techniques and two cluster-finding algorithms are used. In scale-free models with white noise initial conditions, xi sub c and xi are essentially identical. In scale-free models with more power on large scales, it is found that the amplitude of xi sub c increases with cluster richness; in this case the clusters give a biased estimate of the particle correlations. In the pancake and hybrid models (with n = 0 or 1), xi sub c is steeper than xi, but the cluster correlation length exceeds that of the points by less than a factor of 2, independent of cluster richness. Thus the high amplitude of xi sub c found in studies of rich clusters of galaxies is inconsistent with white noise and pancake models and may indicate a primordial fluctuation spectrum with substantial power on large scales. 30 references

  18. Irradiation characteristics of metal-cluster-complex ions containing diverse multi-elements with large mass differences

    International Nuclear Information System (INIS)

    Fujiwara, Yukio; Kondou, Kouji; Teranishi, Yoshikazu; Nonaka, Hidehiko; Saito, Naoaki; Fujimoto, Toshiyuki; Kurokawa, Akira; Ichimura, Shingo; Tomita, Mitsuhiro

    2007-01-01

    Tetrairidium dodecacarbonyl, Ir 4 (CO) 12 , is a metal cluster complex which has a molecular weight of 1104.9. Using a metal-cluster-complex ion source, the interaction between Ir 4 (CO) n + ions (n=0-12) and silicon substrates was studied at a beam energy ranging from 2keV to 10keV at normal incidence. By adjusting Wien-filter voltage, the influence of CO ligands was investigated. Experimental results showed that sputtering yield of silicon bombarded with Ir 4 (CO) n + ions at 10keV decreased with the number of CO ligands. In the case of 2keV, deposition tended to be suppressed by removing CO ligands from the impinging cluster ions. The influence of CO ligands was explained by considering changes in surface properties caused by the irradiation of Ir 4 (CO) n + ions. It was also found that the bombardment with Ir 4 (CO) 7 + ions at 2.5keV caused deposition on silicon target

  19. Phylogenetic networks do not need to be complex: using fewer reticulations to represent conflicting clusters

    NARCIS (Netherlands)

    Iersel, van L.J.J.; Kelk, S.M.; Rupp, R.; Huson, D.H.

    2010-01-01

    Phylogenetic trees are widely used to display estimates of how groups of species are evolved. Each phylogenetic tree can be seen as a collection of clusters, subgroups of the species that evolved from a common ancestor. When phylogenetic trees are obtained for several datasets (e.g. for different

  20. Complex open-framework germanate built by 8-coordinated Ge 10 clusters

    KAUST Repository

    Yue, Huijuan

    2012-11-19

    A novel open-framework germanate |(C 5H 14N 2) 2(C 5H 12N 2) 0.5(H 2O) 2.5|[Ge 12.5O 26(OH) 2] with three-dimensional 10- and 11-ring channels, denoted as SU-67, has been synthesized under hydrothermal conditions using 2-methylpiperazine (MPP) as the structure-directing agent (SDA). The synthesis is intimately related to that of JLG-5, a tubular germanate built from Ge 7 clusters. The influences of synthesis parameters are discussed. A strong influence of the hydrofluoric acid quantity on the resulting cluster building units can be concluded. The framework of SU-67 is based on an elaborate topological pattern of connected Ge 10 clusters forming intersecting 10- and 11-ring channels and has a low framework density (12.4 Ge atoms per 1000 ̊ 3). We have discovered that the topology of SU-67 is a new 8-connected nce-8-I4 1/acd net. Strong hydrogen bonding among the organic SDAs, water molecules, and Ge 10 clusters resulted in helical networks in SU-67. © 2012 American Chemical Society.

  1. Convenient Reduction of Carbonyl Compounds to their ...

    African Journals Online (AJOL)

    NICO

    Alcohols and their derivatives occupy an important position in organic synthesis. ... review also reveals that the reduction of carbonyl compounds ..... 1 H.B. Ji and Y.B. She, Green Oxidation and Reduction, China Petrochemi- cal Press, Beijing ...

  2. Protein Carbonylation in Patients with Myelodysplastic Syndromes

    Czech Academy of Sciences Publication Activity Database

    Hlaváčková, A.; Štikarová, J.; Kotlín, R.; Chrastinová, L.; Šácha, Pavel; Májek, P.; Čermák, J.; Suttnar, J.; Dyr, J. E.

    2015-01-01

    Roč. 126, č. 23 (2015), s. 5232 ISSN 0006-4971. [Annual Meeting and Exposition of the American Society of Hematology /55./. 07.12.2013-10.12.2013, New Orleans] Institutional support: RVO:61388963 Keywords : protein carbonylation * myelodysplastic syndromes Subject RIV: CE - Biochemistry

  3. Identifying and ranking influential spreaders in complex networks by combining a local-degree sum and the clustering coefficient

    Science.gov (United States)

    Li, Mengtian; Zhang, Ruisheng; Hu, Rongjing; Yang, Fan; Yao, Yabing; Yuan, Yongna

    2018-03-01

    Identifying influential spreaders is a crucial problem that can help authorities to control the spreading process in complex networks. Based on the classical degree centrality (DC), several improved measures have been presented. However, these measures cannot rank spreaders accurately. In this paper, we first calculate the sum of the degrees of the nearest neighbors of a given node, and based on the calculated sum, a novel centrality named clustered local-degree (CLD) is proposed, which combines the sum and the clustering coefficients of nodes to rank spreaders. By assuming that the spreading process in networks follows the susceptible-infectious-recovered (SIR) model, we perform extensive simulations on a series of real networks to compare the performances between the CLD centrality and other six measures. The results show that the CLD centrality has a competitive performance in distinguishing the spreading ability of nodes, and exposes the best performance to identify influential spreaders accurately.

  4. Calcium EXAFS establishes the Mn-Ca cluster in the oxygen-evolving complex of Photosystem II

    Energy Technology Data Exchange (ETDEWEB)

    Cinco, Roehl M.; McFarlane Holman, Karen L.; Robblee, John H.; Yano, Junko; Pizarro, Shelly A.; Bellacchio, Emanuele; Sauer, Kenneth; Yachandra, Vittal K.

    2002-08-02

    The proximity of Ca to the Mn cluster of the photosynthetic water-oxidation complex is demonstrated by X-ray absorption spectroscopy. We have collected EXAFS data at the Ca K-edge using active PS II membrane samples that contain approximately 2 Ca per 4 Mn. These samples are much less perturbed than previously investigated Sr-substituted samples, which were prepared subsequent to Ca depletion. The new Ca EXAFS clearly shows backscattering from Mn at 3.4 angstroms, a distance that agrees with that surmised from previously recorded Mn EXAFS. This result is also consistent with earlier related experiments at the Sr K-edge, using samples that contained functional Sr, that show Mn is {approx}; 3.5 angstroms distant from Sr. The totality of the evidence clearly advances the notion that the catalytic center of oxygen evolution is a Mn-Ca heteronuclear cluster.

  5. Production of complex particles in low energy spallation and in fragmentation reactions by in-medium random clusterization

    International Nuclear Information System (INIS)

    Lacroix, D.; Durand, D.

    2005-09-01

    Rules for in-medium complex particle production in nuclear reactions are proposed. These rules have been implemented in two models to simulate nucleon-nucleus and nucleus-nucleus reactions around the Fermi energy. Our work emphasizes the effect of randomness in cluster formation, the importance of the nucleonic Fermi motion as well as the role of conservation laws. The concepts of total available phase-space and explored phase-space under constraint imposed by the reaction are clarified. The compatibility of experimental observations with a random clusterization is illustrated in a schematic scenario of a proton-nucleus collision. The role of randomness under constraint is also illustrated in the nucleus-nucleus case. (authors)

  6. Synthesis, characterization and biological studies of 2-(4-nitrophenylamino-carbonyl)benzoic acid and its complexes with Cr(III), Co(II), Ni(II), Cu(II) and Zn(II)

    International Nuclear Information System (INIS)

    Imran, M; Nazir, S.; Latif, S.; Mahmood, Z.

    2010-01-01

    Cr(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes of 2-(4-Nitrophenyl aminocarbonyl)benzoic acid were synthesized and characterized on the basis of physical, analytical and spectroscopic data. The ligands, as well as its metal complexes were checked for their in-vitro antimicrobial activity against three bacterial strains, Mycobacterium smegmatis, Escherichia coli, Pseudomonas aeuroginosa, and three fungal strains, Nigrospora oryzae, Aspergillus niger and Candida albicans. Disc diffusion method and Tube diffusion test were used for antibacterial and antifungal activities, respectively. The synthesized complexes only show significant antifungal activity but inactive for antibacterial, however, in general, the metal complexes were found to be more active against antimicrobial activities as compared to their un complexed ligand. (author)

  7. Millimeter wave spectra of carbonyl cyanide ⋆

    Science.gov (United States)

    Bteich, S.B.; Tercero, B.; Cernicharo, J.; Motiyenko, R.A.; Margulès, L.; Guillemin, J.-C.

    2016-01-01

    Context More than 30 cyanide derivatives of simple organic molecules have been detected in the interstellar medium, but only one dicarbonitrile has been found and that very recently. There is still a lack of high-resolution spectroscopic data particularly for dinitriles derivatives. The carbonyl cyanide molecule is a new and interesting candidate for astrophysical detection. It could be formed by the reaction of CO and CN radicals, or by substitution of the hydrogen atom by a cyano group in cyanoformaldehyde, HC(=O)CN, that has already been detected in the interstellar medium. Aims The available data on the rotational spectrum of carbonyl cyanide is limited in terms of quantum number values and frequency range, and does not allow accurate extrapolation of the spectrum into the millimeter-wave range. To provide a firm basis for astrophysical detection of carbonyl cyanide we studied its millimeter-wave spectrum. Methods The rotational spectrum of carbonyl cyanide was measured in the frequency range 152 - 308 GHz and analyzed using Watson’s A- and S-reduction Hamiltonians. Results The ground and first excited state of v5 vibrational mode were assigned and analyzed. More than 1100 distinct frequency lines of the ground state were fitted to produce an accurate set of rotational and centrifugal distortion constants up to the eighth order. The frequency predictions based on these constants should be accurate enough for astrophysical searches in the frequency range up to 500 GHz and for transition involving energy levels with J ≤ 100 and Ka ≤ 42. Based on the results we searched for interstellar carbonyl cyanide in available observational data without success. Thus, we derived upper limits to its column density in different sources. PMID:27738349

  8. Method for conversion of .beta.-hydroxy carbonyl compounds

    Science.gov (United States)

    Lilga, Michael A.; White, James F.; Holladay, Johnathan E.; Zacher, Alan H.; Muzatko, Danielle S.; Orth, Rick J.

    2010-03-30

    A process is disclosed for conversion of salts of .beta.-hydroxy carbonyl compounds forming useful conversion products including, e.g., .alpha.,.beta.-unsaturated carbonyl compounds and/or salts of .alpha.,.beta.-unsaturated carbonyl compounds. Conversion products find use, e.g., as feedstock and/or end-use chemicals.

  9. The complex of measures on inclusion of small businesses in innovation clusters

    Directory of Open Access Journals (Sweden)

    A. V. Kupchinsky

    2016-01-01

    Full Text Available Modern practice of managing and its display in scientific publications demonstrate that development of world economy with all evidence proves the major role and the importance of sector of small business structures in national economy. In the modern world the national economy in many respects began to be determined by the balanced and sustainable development of the small business structures recognized now as conductors and creators of new opening and technologies, moreover, as the strategic instrument of the structural transformations of a modern economic system of the country often directed to high-quality increase in efficiency of reproduction process of regional economy. Now in Russia the level of development of an innovative entrepreneurship is very low. It is possible to state lack of properly created institutional environment for development of a small entrepreneurship in the innovative sphere. Clasterisation represents process of consolidation of a number of the organizations of various industries for increase in competitiveness, implementation of innovations, effective development and receipt of other benefits. According to separation of economy on real and virtual, the possibility of creation of both real, and virtual clusters increases. Creation and development of regional clusters will help to create the necessary level of activity of small business structures in innovative activities that will favorably affect increase in competitiveness of both regional, and national economy. The package of measures including measures for involvement of small business structures in clusters is developed for development of a cluster initiative and increase in innovative development of the region. Application of this program will allow to reach synergy effect at the expense of high degree of concentration and cooperation of small business structures and increase in effectiveness of their activities.

  10. Regulation of human Nfu activity in Fe-S cluster delivery-characterization of the interaction between Nfu and the HSPA9/Hsc20 chaperone complex.

    Science.gov (United States)

    Wachnowsky, Christine; Liu, Yushi; Yoon, Taejin; Cowan, J A

    2018-01-01

    Iron-sulfur cluster biogenesis is a complex, but highly regulated process that involves de novo cluster formation from iron and sulfide ions on a scaffold protein, and subsequent delivery to final targets via a series of Fe-S cluster-binding carrier proteins. The process of cluster release from the scaffold/carrier for transfer to the target proteins may be mediated by a dedicated Fe-S cluster chaperone system. In human cells, the chaperones include heat shock protein HSPA9 and the J-type chaperone Hsc20. While the role of chaperones has been somewhat clarified in yeast and bacterial systems, many questions remain over their functional roles in cluster delivery and interactions with a variety of human Fe-S cluster proteins. One such protein, Nfu, has recently been recognized as a potential interaction partner of the chaperone complex. Herein, we examined the ability of human Nfu to function as a carrier by interacting with the human chaperone complex. Human Nfu is shown to bind to both chaperone proteins with binding affinities similar to those observed for IscU binding to the homologous HSPA9 and Hsc20, while Nfu can also stimulate the ATPase activity of HSPA9. Additionally, the chaperone complex was able to promote Nfu function by enhancing the second-order rate constants for Fe-S cluster transfer to target proteins and providing directionality in cluster transfer from Nfu by eliminating promiscuous transfer reactions. Together, these data support a hypothesis in which Nfu can serve as an alternative carrier protein for chaperone-mediated cluster release and delivery in Fe-S cluster biogenesis and trafficking. © 2017 Federation of European Biochemical Societies.

  11. Highly enantioselective rhodium(I)-catalyzed carbonyl carboacylations initiated by C-C bond activation.

    Science.gov (United States)

    Souillart, Laetitia; Cramer, Nicolai

    2014-09-01

    The lactone motif is ubiquitous in natural products and pharmaceuticals. The Tishchenko disproportionation of two aldehydes, a carbonyl hydroacylation, is an efficient and atom-economic access to lactones. However, these reaction types are limited to the transfer of a hydride to the accepting carbonyl group. The transfer of alkyl groups enabling the formation of CC bonds during the ester formation would be of significant interest. Reported herein is such asymmetric carbonyl carboacylation of aldehydes and ketones, thus affording complex bicyclic lactones in excellent enantioselectivities. The rhodium(I)-catalyzed transformation is induced by an enantiotopic CC bond activation of a cyclobutanone and the formed rhodacyclic intermediate reacts with aldehyde or ketone groups to give highly functionalized lactones. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Stereoselective Carbonyl Olefination with Fluorosulfoximines: Facile Access to Z or E Terminal Monofluoroalkenes.

    Science.gov (United States)

    Liu, Qinghe; Shen, Xiao; Ni, Chuanfa; Hu, Jinbo

    2017-01-09

    Terminal monofluoroalkenes are important structural motifs in the design of bioactive compounds, such as homeostasis regulators and mechanism-based enzyme inhibitors. However, it is difficult to control the stereoselectivity of known carbonyl olefination reactions, and olefin metathesis is limited to disubstituted terminal monofluoroalkenes. Although sulfoximines have been used extensively in organic synthesis, reports on their use in carbonyl olefination reactions have not appeared to date. Herein, we report highly stereoselective carbonyl monofluoroolefination with a fluorosulfoximine reagent. The potential of this method is demonstrated by the synthesis of MDL 72161 and by the late-stage monofluoromethylenation of complex molecules, such as haloperidol and steroid derivatives. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Human major histocompatibility complex contains a minimum of 19 genes between the complement cluster and HLA-B

    International Nuclear Information System (INIS)

    Spies, T.; Bresnahan, M.; Strominger, J.L.

    1989-01-01

    A 600-kilobase (kb) DNA segment from the human major histocompatibility complex (MHC) class III region was isolated by extension of a previous 435-kb chromosome walk. The contiguous series of cloned overlapping cosmids contains the entire 555-kb interval between C2 in the complement gene cluster and HLA-B. This region is known to encode the tumor necrosis factors (TNFs) α and β, B144, and the major heat shock protein HSP70. Moreover, a cluster of genes, BAT1-BAT5 (HLA-B-associated transcripts) have been localized in the vicinity of the genes for TNFα and TNFβ. An additional four genes were identified by isolation of corresponding cDNA clones with cosmid DNA probes. These genes for BAT6-BAT9 were mapped near the gene for C2 within a 120-kb region that includes a HSP70 gene pair. These results, together with complementary data from a similar recent study, indicated the presence of a minimum of 19 genes within the C2-HLA-B interval of the MHC class III region. Although the functional properties of most of these genes are yet unknown, they may be involved in some aspects of immunity. This idea is supported by the genetic mapping of the hematopoietic histocompatibility locus-1 (Hh-1) in recombinant mice between TNFα and H-2S, which is homologous to the complement gene cluster in humans

  14. Semi-supervised spectral algorithms for community detection in complex networks based on equivalence of clustering methods

    Science.gov (United States)

    Ma, Xiaoke; Wang, Bingbo; Yu, Liang

    2018-01-01

    Community detection is fundamental for revealing the structure-functionality relationship in complex networks, which involves two issues-the quantitative function for community as well as algorithms to discover communities. Despite significant research on either of them, few attempt has been made to establish the connection between the two issues. To attack this problem, a generalized quantification function is proposed for community in weighted networks, which provides a framework that unifies several well-known measures. Then, we prove that the trace optimization of the proposed measure is equivalent with the objective functions of algorithms such as nonnegative matrix factorization, kernel K-means as well as spectral clustering. It serves as the theoretical foundation for designing algorithms for community detection. On the second issue, a semi-supervised spectral clustering algorithm is developed by exploring the equivalence relation via combining the nonnegative matrix factorization and spectral clustering. Different from the traditional semi-supervised algorithms, the partial supervision is integrated into the objective of the spectral algorithm. Finally, through extensive experiments on both artificial and real world networks, we demonstrate that the proposed method improves the accuracy of the traditional spectral algorithms in community detection.

  15. Constructing a graph of connections in clustering algorithm of complex objects

    Directory of Open Access Journals (Sweden)

    Татьяна Шатовская

    2015-05-01

    Full Text Available The article describes the results of modifying the algorithm Chameleon. Hierarchical multi-level algorithm consists of several phases: the construction of the count, coarsening, the separation and recovery. Each phase can be used various approaches and algorithms. The main aim of the work is to study the quality of the clustering of different sets of data using a set of algorithms combinations at different stages of the algorithm and improve the stage of construction by the optimization algorithm of k choice in the graph construction of k of nearest neighbors

  16. Communication: Relativistic Fock-space coupled cluster study of small building blocks of larger uranium complexes

    International Nuclear Information System (INIS)

    Tecmer, Paweł; Visscher, Lucas; Severo Pereira Gomes, André; Knecht, Stefan

    2014-01-01

    We present a study of the electronic structure of the [UO 2 ] + , [UO 2 ] 2 + , [UO 2 ] 3 + , NUO, [NUO] + , [NUO] 2 + , [NUN] − , NUN, and [NUN] + molecules with the intermediate Hamiltonian Fock-space coupled cluster method. The accuracy of mean-field approaches based on the eXact-2-Component Hamiltonian to incorporate spin–orbit coupling and Gaunt interactions are compared to results obtained with the Dirac–Coulomb Hamiltonian. Furthermore, we assess the reliability of calculations employing approximate density functionals in describing electronic spectra and quantities useful in rationalizing Uranium (VI) species reactivity (hardness, electronegativity, and electrophilicity)

  17. Communication: Relativistic Fock-space coupled cluster study of small building blocks of larger uranium complexes

    Science.gov (United States)

    Tecmer, Paweł; Severo Pereira Gomes, André; Knecht, Stefan; Visscher, Lucas

    2014-07-01

    We present a study of the electronic structure of the [UO2]+, [UO2]2 +, [UO2]3 +, NUO, [NUO]+, [NUO]2 +, [NUN]-, NUN, and [NUN]+ molecules with the intermediate Hamiltonian Fock-space coupled cluster method. The accuracy of mean-field approaches based on the eXact-2-Component Hamiltonian to incorporate spin-orbit coupling and Gaunt interactions are compared to results obtained with the Dirac-Coulomb Hamiltonian. Furthermore, we assess the reliability of calculations employing approximate density functionals in describing electronic spectra and quantities useful in rationalizing Uranium (VI) species reactivity (hardness, electronegativity, and electrophilicity).

  18. Intermolecular vibronic spectroscopy of small van der Waals clusters: Phenol- and aniline-(argon)2 complexes

    International Nuclear Information System (INIS)

    Schmidt, M.; Mons, M.; Le Calve, J.

    1990-01-01

    We report the clear observation and assignment of the symmetric stretching and bending van der Waals modes in two three-body C 2ν complexes, phenol- and aniline-(Ar) 2 , using resonant two-photon ionization. (orig.)

  19. Properties of clusters in the gas phase: V. Complexes of neutral molecules onto negative ions

    International Nuclear Information System (INIS)

    Keesee, R.G.; Lee, N.; Castleman, A.W. Jr.

    1980-01-01

    Ion--molecules association reactions of the form A - (B)/sub n1/-+B=A - (B)/sub n/ were studied over a range of temperatures in the gas phase using high pressure mass spectrometry. Enthalpy and entropy changes were determined for the stepwise clustering reactions of (1) sulfur dioxide onto Cl - , I - , and NO 2 - with n ranging from one to three or four, and onto SO 2 - and SO 3 - with n equal to one; and (2) carbon dioxide onto Cl - , I - , NO 2 - , CO 3 - , and SO 3 - with n equal to one. From these data and earlier hydration results, the order of the magnitude of the enthalpy changes on the association of the first neutral for a series of negative ions was found to parallel the gas-phase basicity of those anions. For any given ion, the relative order of the addition enthalpies among the neutrals was found to be dependent on the polarizabilities of the neutrals and on the covalency in the ion-neutral bond. Dispersion of charge via covalent bonding was found to affect significantly the succeeding clustering steps

  20. Clustered coding variants in the glutamate receptor complexes of individuals with schizophrenia and bipolar disorder.

    Directory of Open Access Journals (Sweden)

    René A W Frank

    2011-04-01

    Full Text Available Current models of schizophrenia and bipolar disorder implicate multiple genes, however their biological relationships remain elusive. To test the genetic role of glutamate receptors and their interacting scaffold proteins, the exons of ten glutamatergic 'hub' genes in 1304 individuals were re-sequenced in case and control samples. No significant difference in the overall number of non-synonymous single nucleotide polymorphisms (nsSNPs was observed between cases and controls. However, cluster analysis of nsSNPs identified two exons encoding the cysteine-rich domain and first transmembrane helix of GRM1 as a risk locus with five mutations highly enriched within these domains. A new splice variant lacking the transmembrane GPCR domain of GRM1 was discovered in the human brain and the GRM1 mutation cluster could perturb the regulation of this variant. The predicted effect on individuals harbouring multiple mutations distributed in their ten hub genes was also examined. Diseased individuals possessed an increased load of deleteriousness from multiple concurrent rare and common coding variants. Together, these data suggest a disease model in which the interplay of compound genetic coding variants, distributed among glutamate receptors and their interacting proteins, contribute to the pathogenesis of schizophrenia and bipolar disorders.

  1. Cluster analysis in soft X-ray spectromicroscopy: finding the patterns in complex specimens

    International Nuclear Information System (INIS)

    Lerotic, M.; Jacobsen, C.

    2004-01-01

    Full text: Soft x-ray spectromicroscopy provides spectral data on the chemical speciation of light elements at sub-100 nanometer spatial resolution. When all chemical species in a specimen are known and separately characterized, existing approaches can be used to measure the concentration of each component at each pixel. In other situations such as in biology or environmental science, this approach may not be possible. A method to find natural groupings of data without prior knowledge of the spectra of all components will be presented. Principal component analysis is used to orthogonalize spectromicroscopy data, and discard much of the noise present in data set. Then cluster analysis is used to find a hierarchical classification of pixels with similar spectra, to extract representative, cluster-averaged spectra with good signal-to-noise ratio, and to obtain gradations of concentration of these representative spectra at each pixel. The method is illustrated with a simulated data set of organic compounds, and a mixture of lutetium in hematite used to understand colloidal transport properties of radionuclides. We gratefully acknowledge funding from the National Institutes for Health under contract R01 EB00479-01A1, and from the National Science Foundation under contracts OCE-0221029 and CHE-0221934

  2. Organocatalytic Hydrophosphonylation Reaction of Carbonyl Groups.

    Science.gov (United States)

    Herrera, Raquel P

    2017-09-01

    This revision is covering the limited examples reported for a pivotal strategy in the formation of C-P bonds such as the asymmetric organocatalytic hydrophosphonylation of carbonyl groups (Pudovik reaction). The scope and limitations, and the proposed mechanisms for the scarce different possibilities of asymmetric induction are also shown. The recent evolution and future trends of this undeveloped approach are commented. © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Spatiotemporal distribution of carbonyl compounds in China.

    Science.gov (United States)

    Ho, K F; Ho, Steven Sai Hang; Huang, R-J; Dai, W T; Cao, J J; Tian, Linwei; Deng, W J

    2015-02-01

    A sampling campaign was carried out at nine Chinese cities in 2010/2011. Fifteen monocarbonyls (C# = 1-9) were quantified. Temperature is the rate-determining factor of the summertime carbonyl levels. The carbonyl emissions in winter are mainly driven by the primary anthropogenic sources like automobile. A molar ratio of propionaldehyde to nonaldehyde is a barometer of the impact of atmospheric vegetation emission which suggesting that strong vegetation emissions exist in summer and high propionaldehyde abundance is caused by fossil fuel combustion in winter. Potential health risk assessment of formaldehyde and acetaldehyde was conducted and the highest cumulative risks were observed at Chengdu in summer and Wuhan in winter. Because of the strong photochemical reaction and large amount of anthropogenic emissions, high concentrations of carbonyl compounds were observed in Chengdu. The use of ethanol-blended gasoline in Wuhan is the key reason of acetaldehyde emission and action should be taken to avoid potential health risks. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Carbonyl Compounds Generated from Electronic Cigarettes

    Directory of Open Access Journals (Sweden)

    Kanae Bekki

    2014-10-01

    Full Text Available Electronic cigarettes (e-cigarettes are advertised as being safer than tobacco cigarettes products as the chemical compounds inhaled from e-cigarettes are believed to be fewer and less toxic than those from tobacco cigarettes. Therefore, continuous careful monitoring and risk management of e-cigarettes should be implemented, with the aim of protecting and promoting public health worldwide. Moreover, basic scientific data are required for the regulation of e-cigarette. To date, there have been reports of many hazardous chemical compounds generated from e-cigarettes, particularly carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal, which are often found in e-cigarette aerosols. These carbonyl compounds are incidentally generated by the oxidation of e-liquid (liquid in e-cigarette; glycerol and glycols when the liquid comes in contact with the heated nichrome wire. The compositions and concentrations of these compounds vary depending on the type of e-liquid and the battery voltage. In some cases, extremely high concentrations of these carbonyl compounds are generated, and may contribute to various health effects. Suppliers, risk management organizations, and users of e-cigarettes should be aware of this phenomenon.

  5. Palladium-catalyzed Reppe carbonylation.

    Science.gov (United States)

    Kiss, G

    2001-11-01

    PdX2L2/L/HA (A = weakly coordinating anion, L = phosphine) complexes are active catalysts in the hydroesterification of alkenes, alkynes, and conjugated dienes. Shell, the only major corporate player in the field, recently developed two very active catalyst systems tailored to the hydroesterification of either alkenes or alkynes. The hydroesterification of propyne with their Pd(OAc)2/PN/HA (PN = (2-pyridyl)diphenylphosphine, HA = strong acid with weakly coordinating anion, like methanesulfonic acid) catalyst has been declared commercially ready. However, despite the significant progress in the activity of Pd-hydroesterification catalysts, further improvements are warranted. Thus, for example, activity maintenance still seems to be an issue. Homogeneous Pd catalysts are prone to a number of deactivation reactions. Activity and stability promoters are often corrosive and add to the complexity of the system, making it less attractive. Nonetheless, the versatility of the process and its tolerance toward the functional groups of substrates should appeal especially to the makers of specialty products. Although hydroesterification yields esters from alkenes, alkynes, and dienes in fewer steps than hydroformylation does, the latter has some advantages at the current state of the art. (1) Hydroformylation catalysts, particularly some recently published phosphine-modified Rh systems, can achieve very high regioselectivity for the linear product that hydroesterification catalysts cannot match yet. By analogy with hydroformylation, bulkier ligands ought to be tested in hydroesterification to increase normal-ester selectivity. (2) Hydroformylation is proven, commercial. Hydroesterification can only replace it if it can provide significant economic incentives. Similar or just marginally better performance could not justify the cost of development of a new technology. (3) Hydroesterification requires pure CO while hydroformylation uses syngas, a mixture of CO and H2. The latter

  6. Cluster analysis in soft X-ray spectromicroscopy: Finding the patterns in complex specimens

    Energy Technology Data Exchange (ETDEWEB)

    Lerotic, M. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, NY 11794-3800 (United States)]. E-mail: lerotic@xray1.physics.sunysb.edu; Jacobsen, C. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, NY 11794-3800 (United States); Gillow, J.B. [Environmental Sciences Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Francis, A.J. [Environmental Sciences Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Wirick, S. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, NY 11794-3800 (United States); Vogt, S. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Maser, J. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2005-06-15

    Soft X-ray spectromicroscopy provides spectral data on the chemical speciation of light elements at sub-100 nanometer spatial resolution. If all chemical species in a specimen are known and separately characterized, existing approaches can be used to measure the concentration of each component at each pixel. In other situations such as in biology or environmental science, this approach may not be possible. We have previously described [M. Lerotic, C. Jacobsen, T. Schaefer, S. Vogt, Ultramicroscopy 100 (1-2) (2004) 35] the use of principle component analysis (PCA) to orthogonalize and noise-filter spectromicroscopy data, and cluster analysis (Canada) to classify the analyzed data and obtain thickness maps of representative spectra. We describe here an extension of that work employing an angle distance measure; this measure provides better classification based on spectral signatures alone in specimens with significant thickness variations. The method is illustrated using simulated data, and also to examine sporulation in the bacterium Clostridium sp.

  7. Photo-induced transformation process at gold clusters-semiconductor interface: Implications for the complexity of gold clusters-based photocatalysis

    Science.gov (United States)

    Liu, Siqi; Xu, Yi-Jun

    2016-03-01

    The recent thrust in utilizing atomically precise organic ligands protected gold clusters (Au clusters) as photosensitizer coupled with semiconductors for nano-catalysts has led to the claims of improved efficiency in photocatalysis. Nonetheless, the influence of photo-stability of organic ligands protected-Au clusters at the Au/semiconductor interface on the photocatalytic properties remains rather elusive. Taking Au clusters-TiO2 composites as a prototype, we for the first time demonstrate the photo-induced transformation of small molecular-like Au clusters to larger metallic Au nanoparticles under different illumination conditions, which leads to the diverse photocatalytic reaction mechanism. This transformation process undergoes a diffusion/aggregation mechanism accompanied with the onslaught of Au clusters by active oxygen species and holes resulting from photo-excited TiO2 and Au clusters. However, such Au clusters aggregation can be efficiently inhibited by tuning reaction conditions. This work would trigger rational structural design and fine condition control of organic ligands protected-metal clusters-semiconductor composites for diverse photocatalytic applications with long-term photo-stability.

  8. Millimeter wave spectra of carbonyl cyanide

    Science.gov (United States)

    Bteich, S. B.; Tercero, B.; Cernicharo, J.; Motiyenko, R. A.; Margulès, L.; Guillemin, J.-C.

    2016-07-01

    Context. More than 30 cyanide derivatives of simple organic molecules have been detected in the interstellar medium, but only one dicarbonitrile has been found and that very recently. There is still a lack of high-resolution spectroscopic data particularly for dinitriles derivatives. The carbonyl cyanide molecule is a new and interesting candidate for astrophysical detection. It could be formed by the reaction of CO and CN radicals, or by substitution of the hydrogen atom by a cyano group in cyanoformaldehyde, HC(=O)CN, that has already been detected in the interstellar medium. Aims: The available data on the rotational spectrum of carbonyl cyanide is limited in terms of quantum number values and frequency range, and does not allow accurate extrapolation of the spectrum into the millimeter-wave range. To provide a firm basis for astrophysical detection of carbonyl cyanide we studied its millimeter-wave spectrum. Methods: The rotational spectrum of carbonyl cyanide was measured in the frequency range 152-308 GHz and analyzed using Watson's A- and S-reduction Hamiltonians. Results: The ground and first excited state of v5 vibrational mode were assigned and analyzed. More than 1100 distinct frequency lines of the ground state were fitted to produce an accurate set of rotational and centrifugal distortion constants up to the eighth order. The frequency predictions based on these constants should be accurate enough for astrophysical searches in the frequency range up to 500 GHz and for transition involving energy levels with J ≤ 100 and Ka ≤ 42. Based on the results we searched for interstellar carbonyl cyanide in available observational data without success. Thus, we derived upper limits to its column density in different sources. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00009.SV. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan) with NRC (Canada), NSC, and ASIAA (Taiwan), and KASI (Republic of

  9. Studies on cluster, salt and molecular complex of zinc-quinolinate

    Indian Academy of Sciences (India)

    Reactions of zinc halides with 8-hydroxyquinoline (hydroxQ) in equimolar ratio were carried out in different solvents. ... determination of surface area. We prepared a ..... resulted in the formation of de-solvated complex, which on standing at ...

  10. Ruthenium(II) carbonyl compounds with the 4'-chloro-2,2':6',2''-terpyridine ligand.

    Science.gov (United States)

    Tatikonda, Rajendhraprasad; Haukka, Matti

    2017-04-01

    Two ruthenium carbonyl complexes with the 4'-chloro-2,2':6',2''-terpyridine ligand (tpy-Cl, C 15 H 10 ClN 3 ), i.e. [RuCl(tpy-Cl)(CO) 2 ][RuCl 3 (CO) 3 ] (I) [systematic name: cis -di-carbonyl-chlorido(4'-chloro-2,2':6',2''-terpyridine-κ 3 N )ruthenium(II) fac -tricarbonyltri-chlorido-ruthenate(II)], and [RuCl 2 (tpy-Cl)(CO) 2 ] (II) [ cis -dicarbonyl- trans -di-chlorido(4'-chloro-2,2':6',2''-terpyridine-κ 2 N 1 , N 1' )ruthenium(II)], were synthesized and characterized by single-crystal X-ray diffraction. The Ru II atoms in both centrosymmetric structures (I) and (II) display similar, slightly distorted octa-hedral coordination spheres. The coordination sphere in the complex cation in compound (I) is defined by three N atoms of the tridentate tpy-Cl ligand, two carbonyl carbon atoms and one chlorido ligand; the charge is balanced by an octa-hedral [Ru(CO) 3 Cl 3 ] - counter-anion. In the neutral compound (II), the tpy-Cl ligand coordinates to the metal only through two of its N atoms. The coordination sphere of the Ru II atom is completed by two carbonyl and two chlorido ligands. In the crystal structures of both (I) and (II), weak C-H⋯Cl inter-actions are observed.

  11. Validation of protein carbonyl measurement: A multi-centre study

    Directory of Open Access Journals (Sweden)

    Edyta Augustyniak

    2015-04-01

    Full Text Available Protein carbonyls are widely analysed as a measure of protein oxidation. Several different methods exist for their determination. A previous study had described orders of magnitude variance that existed when protein carbonyls were analysed in a single laboratory by ELISA using different commercial kits. We have further explored the potential causes of variance in carbonyl analysis in a ring study. A soluble protein fraction was prepared from rat liver and exposed to 0, 5 and 15 min of UV irradiation. Lyophilised preparations were distributed to six different laboratories that routinely undertook protein carbonyl analysis across Europe. ELISA and Western blotting techniques detected an increase in protein carbonyl formation between 0 and 5 min of UV irradiation irrespective of method used. After irradiation for 15 min, less oxidation was detected by half of the laboratories than after 5 min irradiation. Three of the four ELISA carbonyl results fell within 95% confidence intervals. Likely errors in calculating absolute carbonyl values may be attributed to differences in standardisation. Out of up to 88 proteins identified as containing carbonyl groups after tryptic cleavage of irradiated and control liver proteins, only seven were common in all three liver preparations. Lysine and arginine residues modified by carbonyls are likely to be resistant to tryptic proteolysis. Use of a cocktail of proteases may increase the recovery of oxidised peptides. In conclusion, standardisation is critical for carbonyl analysis and heavily oxidised proteins may not be effectively analysed by any existing technique.

  12. Carbonyl Emissions from Gasoline and Diesel Motor Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Destaillats, Hugo; Jakober, Chris A.; Robert, Michael A.; Riddle, Sarah G.; Destaillats, Hugo; Charles, M. Judith; Green, Peter G.; Kleeman, Michael J.

    2007-12-01

    Carbonyls from gasoline powered light-duty vehicles (LDVs) and heavy-duty diesel powered vehicles (HDDVs) operated on chassis dynamometers were measured using an annular denuder-quartz filter-polyurethane foam sampler with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine derivatization and chromatography-mass spectrometry analyses. Two internal standards were utilized based on carbonyl recovery, 4-fluorobenzaldehyde forcarbonyls and 6-fluoro-4-chromanone for>_C8 compounds. Gas- and particle-phase emissions for 39 aliphatic and 20 aromatic carbonyls ranged from 0.1 ? 2000 ?g/L fuel for LDVs and 1.8 - 27000 mu g/L fuel for HDDVs. Gas-phase species accounted for 81-95percent of the total carbonyls from LDVs and 86-88percent from HDDVs. Particulate carbonyls emitted from a HDDV under realistic driving conditions were similar to concentrations measured in a diesel particulate matter (PM) standard reference material. Carbonyls accounted for 19percent of particulate organic carbon (POC) emissions from low-emission LDVs and 37percent of POC emissions from three-way catalyst equipped LDVs. This identifies carbonyls as one of the largest classes of compounds in LDV PM emissions. The carbonyl fraction of HDDV POC was lower, 3.3-3.9percent depending upon operational conditions. Partitioning analysis indicates the carbonyls had not achieved equilibrium between the gas- and particle-phase under the dilution factors of 126-584 used in the current study.

  13. Product development strategy in the Danish agricultural complex: Global interaction with clusters of marketing excellence

    DEFF Research Database (Denmark)

    Kristensen, Preben Sander

    1992-01-01

    A study of the Danish foods industry shows that producers of food products have built up and maintain development of end-user products in interaction with customers in distant sophisticated markets. Concurrently, the Danish agro-industrial complex been singled out in other studies as a paradigmatic...... produce and utilize sticky and fastchanging information about production and markets respectively. It is precisely by not interacting wi market business-to-business demand from changing end-user market that the Danish agro-industrial complex has avoided being insulated. The managerial implication...... is that a company in search of partners for joint development in global agro-industra networks can realize a competitive advantage by applying a market view that is euclidean upstream and equidstant downstream....

  14. Silver-tellurolate polynuclear complexes: from isolated cluster units to extended polymer chains

    International Nuclear Information System (INIS)

    Corrigan, J.F.; Fenske, D.; Power, W.P.

    1997-01-01

    In the presence of tertiary phosphanes, AgCl reacts readily with the reagent Te(Ph)SiMe 3 to yield silver - tellurolate polynuclear complexes. In the case of PMe 3 , the polymer [Ag 10 (μ 3 -TePh) 10 (PMe 3 ) 2 ] ∞ (shown below) is formed, in which the TePh ligands seve as both inter- and intracluster bridges. (orig.)

  15. Reactions of rhodium(I) carbonyl chloride with olefins

    International Nuclear Information System (INIS)

    Varshavskii, Yu.S.; Kiseleva, N.V.; Cherkasova, T.G.; Buzina, N.A.; Bresler, L.S.

    1987-01-01

    The reactions of [Rh(CO) 2 Cl] 2 (Y 0 ) with cyclooctene and several other olefins (1-heptene, 1-hexene, ethylene, and cyclohexene) have been studied by IR and 13 C NMR spectroscopy. The main reaction products are the binuclear complexes Rh 2 L(CO) 3 Cl 2 (Y 1 ) and [RhL(CO)Cl] 2 (Y 2 ), where L denotes the olefin. The extent of replacement of the carbonyl groups depends on the nature of the olefin and the conditions under which the reaction is carried out (the L:Rh ratio and the removal of CO from the reaction sphere). The liquid olefins form the following series according to their ability to replace the carbonyl groups: C 8 H 14 > C 7 H 14 , C 6 H 12 > C 6 H 10 . In the presence of an excess of C 8 H 14 , Y 2 disproportionates with the formation of a dicarbonyl product, which presumably corresponds to the formula Rh(C 8 H 14 ) 2 (CO) 2 Cl (a pentacoordinate complex with a trigonal-bipyramidal structure). The 13 C signal in the NMR spectrum of a solution of Y 2 in C 8 H 14 is a singlet with σ( 13 C) 180.3 ppm, which is an indication of the rapid exchange of the carbonyl groups. Rapid exchange of the CO ligands is also observed in solutions of Y 0 in the olefins (with the exception of C 6 H 10 ). For example, the 13 C signal in the spectrum of a solution of Y 0 in C 8 H 14 is a singlet with σ( 13 C) 179.8 ppm. The spectrum of Y 0 in C 6 H 10 is a doublet with σ( 13 C) = 178.5 ppm and 1 J(CRh) = 76.3 Hz. A scheme for the interaction of Y 0 with olefins based on the conception of the trans antagonism of π-acceptor ligands has been proposed

  16. The magnetorheological fluid of carbonyl iron suspension blended with grafted MWCNT or graphene

    Science.gov (United States)

    Rwei, Syang-Peng; Ranganathan, Palraj; Chiang, Whe-Yi; Wang, Tza-Yi

    2017-12-01

    In this work, the magnetorheological (MR) fluids containing MWCNT/CI (carbonyl iron) complex and graphene/CI complex were prepared and have the better dispersity in silicone oil than CI powders alone. 1, 4-Aminobenzoic acid (PABA) was used as a grafting agent to modify CI powders to have NH2-end-group so that such nanoparticles can adsorb to acid-treated MWCNT or graphene via attraction of NH2 and COOH groups. The MWCNT/CI complex and graphene/CI complex have a structure of carbonyl iron nanoparticles adsorbed to MWCNT and graphene by self assembly, respectively. Because the carbonyl iron particles possessing magnetic permeability in nanometer scale adsorb to MWCNT or graphene which usually has a nanometer-scaled diameter and a micrometer-scaled length in this work, the dispersity of MWCNT/CI or graphene/CI complex in silicone oil is superior than the previous report [15] that the micrometer-scaled carbonyl iron microspheres were coated with multiwalled carbon nanotubes. Among CI (unmodified), MWCNT/CI and graphene/CI, graphene/CI has the best dispersity while MWCNT/CI still has the better dispersity than unmodified CI. At the temperature T = 300 K, the saturation magnetizations of CI, MWCNT/CI, graphene/CI are 208, 211 emu/g, and 204 emu/g, respectively, indicating that MWCNT/CI complex and graphene/CI complex still maintain the saturation magnetization as high as CI without being interfered by the blended MWCNT or graphene. A wide dynamic range of the yield stress adjusted through varying the electric current can be achieved by the MR fluids containing 69 wt% MWCNT/CI and graphene/CI which is useful in a shock absorber or damper. The result of the yield stress indicates the suspended MWCNT/CI particles are oriented more easily toward the direction perpendicular to the flow direction to block the flow stream lines.

  17. Hierarchical and Complex System Entropy Clustering Analysis Based Validation for Traditional Chinese Medicine Syndrome Patterns of Chronic Atrophic Gastritis.

    Science.gov (United States)

    Zhang, Yin; Liu, Yue; Li, Yannan; Zhao, Xia; Zhuo, Lin; Zhou, Ajian; Zhang, Li; Su, Zeqi; Chen, Cen; Du, Shiyu; Liu, Daming; Ding, Xia

    2018-03-22

    Chronic atrophic gastritis (CAG) is the precancerous stage of gastric carcinoma. Traditional Chinese Medicine (TCM) has been widely used in treating CAG. This study aimed to reveal core pathogenesis of CAG by validating the TCM syndrome patterns and provide evidence for optimization of treatment strategies. This is a cross-sectional study conducted in 4 hospitals in China. Hierarchical clustering analysis (HCA) and complex system entropy clustering analysis (CSECA) were performed, respectively, to achieve syndrome pattern validation. Based on HCA, 15 common factors were assigned to 6 syndrome patterns: liver depression and spleen deficiency and blood stasis in the stomach collateral, internal harassment of phlegm-heat and blood stasis in the stomach collateral, phlegm-turbidity internal obstruction, spleen yang deficiency, internal harassment of phlegm-heat and spleen deficiency, and spleen qi deficiency. By CSECA, 22 common factors were assigned to 7 syndrome patterns: qi deficiency, qi stagnation, blood stasis, phlegm turbidity, heat, yang deficiency, and yin deficiency. Combination of qi deficiency, qi stagnation, blood stasis, phlegm turbidity, heat, yang deficiency, and yin deficiency may play a crucial role in CAG pathogenesis. In accord with this, treatment strategies by TCM herbal prescriptions should be targeted to regulating qi, activating blood, resolving turbidity, clearing heat, removing toxin, nourishing yin, and warming yang. Further explorations are needed to verify and expand the current conclusions.

  18. Quick detection of QRS complexes and R-waves using a wavelet transform and K-means clustering.

    Science.gov (United States)

    Xia, Yong; Han, Junze; Wang, Kuanquan

    2015-01-01

    Based on the idea of telemedicine, 24-hour uninterrupted monitoring on electrocardiograms (ECG) has started to be implemented. To create an intelligent ECG monitoring system, an efficient and quick detection algorithm for the characteristic waveforms is needed. This paper aims to give a quick and effective method for detecting QRS-complexes and R-waves in ECGs. The real ECG signal from the MIT-BIH Arrhythmia Database is used for the performance evaluation. The method proposed combined a wavelet transform and the K-means clustering algorithm. A wavelet transform is adopted in the data analysis and preprocessing. Then, based on the slope information of the filtered data, a segmented K-means clustering method is adopted to detect the QRS region. Detection of the R-peak is based on comparing the local amplitudes in each QRS region, which is different from other approaches, and the time cost of R-wave detection is reduced. Of the tested 8 records (total 18201 beats) from the MIT-BIH Arrhythmia Database, an average R-peak detection sensitivity of 99.72 and a positive predictive value of 99.80% are gained; the average time consumed detecting a 30-min original signal is 5.78s, which is competitive with other methods.

  19. Implementing a complex intervention to support personal recovery: a qualitative study nested within a cluster randomised controlled trial.

    Science.gov (United States)

    Leamy, Mary; Clarke, Eleanor; Le Boutillier, Clair; Bird, Victoria; Janosik, Monika; Sabas, Kai; Riley, Genevieve; Williams, Julie; Slade, Mike

    2014-01-01

    To investigate staff and trainer perspectives on the barriers and facilitators to implementing a complex intervention to help staff support the recovery of service users with a primary diagnosis of psychosis in community mental health teams. Process evaluation nested within a cluster randomised controlled trial (RCT). 28 interviews with mental health care staff, 3 interviews with trainers, 4 focus groups with intervention teams and 28 written trainer reports. 14 community-based mental health teams in two UK sites (one urban, one semi-rural) who received the intervention. The factors influencing the implementation of the intervention can be organised under two over-arching themes: Organisational readiness for change and Training effectiveness. Organisational readiness for change comprised three sub-themes: NHS Trust readiness; Team readiness; and Practitioner readiness. Training effectiveness comprised three sub-themes: Engagement strategies; Delivery style and Modelling recovery principles. Three findings can inform future implementation and evaluation of complex interventions. First, the underlying intervention model predicted that three areas would be important for changing practice: staff skill development; intention to implement; and actual implementation behaviour. This study highlighted the importance of targeting the transition from practitioners' intent to implement to actual implementation behaviour, using experiential learning and target setting. Second, practitioners make inferences about organisational commitment by observing the allocation of resources, Knowledge Performance Indicators and service evaluation outcome measures. These need to be aligned with recovery values, principles and practice. Finally, we recommend the use of organisational readiness tools as an inclusion criteria for selecting both organisations and teams in cluster RCTs. We believe this would maximise the likelihood of adequate implementation and hence reduce waste in research

  20. Implementing a complex intervention to support personal recovery: a qualitative study nested within a cluster randomised controlled trial.

    Directory of Open Access Journals (Sweden)

    Mary Leamy

    Full Text Available OBJECTIVE: To investigate staff and trainer perspectives on the barriers and facilitators to implementing a complex intervention to help staff support the recovery of service users with a primary diagnosis of psychosis in community mental health teams. DESIGN: Process evaluation nested within a cluster randomised controlled trial (RCT. PARTICIPANTS: 28 interviews with mental health care staff, 3 interviews with trainers, 4 focus groups with intervention teams and 28 written trainer reports. SETTING: 14 community-based mental health teams in two UK sites (one urban, one semi-rural who received the intervention. RESULTS: The factors influencing the implementation of the intervention can be organised under two over-arching themes: Organisational readiness for change and Training effectiveness. Organisational readiness for change comprised three sub-themes: NHS Trust readiness; Team readiness; and Practitioner readiness. Training effectiveness comprised three sub-themes: Engagement strategies; Delivery style and Modelling recovery principles. CONCLUSIONS: Three findings can inform future implementation and evaluation of complex interventions. First, the underlying intervention model predicted that three areas would be important for changing practice: staff skill development; intention to implement; and actual implementation behaviour. This study highlighted the importance of targeting the transition from practitioners' intent to implement to actual implementation behaviour, using experiential learning and target setting. Second, practitioners make inferences about organisational commitment by observing the allocation of resources, Knowledge Performance Indicators and service evaluation outcome measures. These need to be aligned with recovery values, principles and practice. Finally, we recommend the use of organisational readiness tools as an inclusion criteria for selecting both organisations and teams in cluster RCTs. We believe this would

  1. A highly efficient nano-cluster artificial peroxidase and its direct electrochemistry on a nano complex modified glassy carbon electrode.

    Science.gov (United States)

    Hong, Jun; Wang, Wei; Huang, Kun; Yang, Wei-Yun; Zhao, Ying-Xue; Xiao, Bao-Lin; Gao, Yun-Fei; Moosavi-Movahedi, Zainab; Ghourchian, Hedayatollah; Moosavi-Movahedi, Ali Akbar

    2012-01-01

    A nano-cluster with highly efficient peroxide activity was constructed based on nafion (NF) and cytochrome c (Cyt c). UV-Vis spectrometry and transmission electron microscopy (TEM) methods were utilized for characterization of the nano-structured enzyme or artificial peroxidase (AP). The nano-cluster was composed of a Chain-Ball structure, with an average ball size of about 40 nm. The Michaelis-Menten (K(m)) and catalytic rate (k(cat)) constants of the AP were determined to be 2.5 ± 0.4 µM and 0.069 ± 0.001 s(-1), respectively, in 50 mM PBS at pH 7.0. The catalytic efficiency of the AP was evaluated to be 0.028 ± 0.005 µM(-1) s(-1), which was 39 ± 5% as efficient as the native horseradish peroxidase (HRP). The AP was also immobilized on a functional multi-wall carbon nanotube (MWNCTs)-gold colloid nanoparticles (AuNPs) nano-complex modified glassy carbon (GC) electrode. The cyclic voltammetry of AP on the nano complex modified GC electrode showed a pair of well-defined redox peaks with a formal potential (E°') of -45 ± 2 mV (vs. Ag/AgCl) at a scan rate of 0.05 V/s. The heterogeneous electron transfer rate constant (k(s)) was evaluated to be 0.65 s(-1). The surface concentration of electroactive AP on GC electrode (Γ) was 7 × 10(-10) mol cm(-2). The apparent Michaelis-Menten constant (K(m)(app)) was 0.23 nM.

  2. Characterization of selected volatile organic compounds, polycyclic aromatic hydrocarbons and carbonyl compounds at a roadside monitoring station

    Science.gov (United States)

    Ho, K. F.; Lee, S. C.; Chiu, Gloria M. Y.

    Volatile organic compounds (VOCs), PAHs and carbonyl compounds are the major toxic components in Hong Kong. Emissions from motor vehicles have been one of the primary pollution sources in the metropolitan areas throughout Hong Kong for a long time. A 1-yr monitoring program for VOCs, PAHs and carbonyl compounds had been performed at a roadside urban station at Hong Kong Polytechnic University in order to determine the variations and correlations of each selected species (VOCs, PAHs and carbonyl compounds). This study is aimed to analyze toxic volatile organic compounds (benzene, toluene, ethylbenzene and xylene), two carbonyl compounds (formaldehyde, acetaldehyde), and selective polycyclic aromatic hydrocarbons. The monitoring program started from 16 April 1999 to 30 March 2000. Ambient VOC concentrations, many of which originate from the same sources as particulate PAHs and carbonyls compounds, show significant quantities of benzene, toluene and xylenes. Correlations and multivariate analysis of selected gaseous and particulate phase organic pollutants were performed. Source identification by principle component analysis and hierarchical cluster analysis allowed the identification of four sources (factors) for the roadside monitoring station. Factor 1 represents the effect of diesel vehicle exhaust. Factor 2 shows the contribution of aromatic compounds. Factor 3 explains photochemical products—formaldehyde and acetaldehyde. Factor 4 explains the effect of gasoline vehicle exhaust.

  3. Interaction of particles with complex electrostatic structures and 3D clusters

    International Nuclear Information System (INIS)

    Antonova, Tetyana

    2007-01-01

    Particles of micrometer size externally introduced in plasmas usually find their positions of levitation in the plasma sheath, where the gravity force is compensated by the strong electric field. Here due to electrostatic interaction they form different structures, which are interesting objects for the investigation of strongly coupled systems and critical phenomena. Because of the low damping (e.g. in comparison to colloidal suspension) it is possible to measure the dynamics up to the relevant highest frequency (e.g. Einstein frequency) at the most elementary level of single particle motion. The task of this work was to analyze the three dimensional structure, dynamical processes and the limit of the cooperative behavior in small plasma crystals. In addition to the study of the systems formed, the immersed particles themselves may be used for diagnostics of the plasma environment: estimation of parameters or monitoring of the processes inside plasma. The laboratory experiments are performed in two radio-frequency (RF) plasma reactors with parallel plate electrodes, where the lower electrode is a so-called ''adaptive electrode''. This electrode is segmented into 57 small ''pixels'' independently driven in DC (direct current) and/or RF voltage. When RF voltage is applied to one of these pixels, a bright localized glow, ''secondary plasma ball'', appears above. Three dimensional dust crystals with less than 100 particles are formed inside this ''plasma ball'' - the ideal conditions for the investigation of the transition from cluster systems to collective systems. The investigation of the particle interactions in crystals is performed with an optical diagnostic, which allows determination of all three particle coordinates simultaneously with time resolution of 0.04 sec. The experimental results are: 1. The binary interaction among particles in addition to the repelling Coulomb force exhibits also an attractive part, which is experimentally determined for the first

  4. Interaction of particles with complex electrostatic structures and 3D clusters

    Energy Technology Data Exchange (ETDEWEB)

    Antonova, Tetyana

    2007-10-16

    Particles of micrometer size externally introduced in plasmas usually find their positions of levitation in the plasma sheath, where the gravity force is compensated by the strong electric field. Here due to electrostatic interaction they form different structures, which are interesting objects for the investigation of strongly coupled systems and critical phenomena. Because of the low damping (e.g. in comparison to colloidal suspension) it is possible to measure the dynamics up to the relevant highest frequency (e.g. Einstein frequency) at the most elementary level of single particle motion. The task of this work was to analyze the three dimensional structure, dynamical processes and the limit of the cooperative behavior in small plasma crystals. In addition to the study of the systems formed, the immersed particles themselves may be used for diagnostics of the plasma environment: estimation of parameters or monitoring of the processes inside plasma. The laboratory experiments are performed in two radio-frequency (RF) plasma reactors with parallel plate electrodes, where the lower electrode is a so-called 'adaptive electrode'. This electrode is segmented into 57 small 'pixels' independently driven in DC (direct current) and/or RF voltage. When RF voltage is applied to one of these pixels, a bright localized glow, 'secondary plasma ball', appears above. Three dimensional dust crystals with less than 100 particles are formed inside this 'plasma ball' - the ideal conditions for the investigation of the transition from cluster systems to collective systems. The investigation of the particle interactions in crystals is performed with an optical diagnostic, which allows determination of all three particle coordinates simultaneously with time resolution of 0.04 sec. The experimental results are: 1. The binary interaction among particles in addition to the repelling Coulomb force exhibits also an attractive part, which is

  5. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others

    1995-12-01

    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  6. Structural insights into Rhino-Deadlock complex for germline piRNA cluster specification.

    Science.gov (United States)

    Yu, Bowen; Lin, Yu An; Parhad, Swapnil S; Jin, Zhaohui; Ma, Jinbiao; Theurkauf, William E; Zhang, Zz Zhao; Huang, Ying

    2018-06-01

    PIWI-interacting RNAs (piRNAs) silence transposons in germ cells to maintain genome stability and animal fertility. Rhino, a rapidly evolving heterochromatin protein 1 (HP1) family protein, binds Deadlock in a species-specific manner and so defines the piRNA-producing loci in the Drosophila genome. Here, we determine the crystal structures of Rhino-Deadlock complex in Drosophila melanogaster and simulans In both species, one Rhino binds the N-terminal helix-hairpin-helix motif of one Deadlock protein through a novel interface formed by the beta-sheet in the Rhino chromoshadow domain. Disrupting the interface leads to infertility and transposon hyperactivation in flies. Our structural and functional experiments indicate that electrostatic repulsion at the interaction interface causes cross-species incompatibility between the sibling species. By determining the molecular architecture of this piRNA-producing machinery, we discover a novel HP1-partner interacting mode that is crucial to piRNA biogenesis and transposon silencing. We thus explain the cross-species incompatibility of two sibling species at the molecular level. © 2018 The Authors.

  7. Small-volume potentiometric titrations: EPR investigations of Fe-S cluster N2 in mitochondrial complex I.

    Science.gov (United States)

    Wright, John J; Salvadori, Enrico; Bridges, Hannah R; Hirst, Judy; Roessler, Maxie M

    2016-09-01

    EPR-based potentiometric titrations are a well-established method for determining the reduction potentials of cofactors in large and complex proteins with at least one EPR-active state. However, such titrations require large amounts of protein. Here, we report a new method that requires an order of magnitude less protein than previously described methods, and that provides EPR samples suitable for measurements at both X- and Q-band microwave frequencies. We demonstrate our method by determining the reduction potential of the terminal [4Fe-4S] cluster (N2) in the intramolecular electron-transfer relay in mammalian respiratory complex I. The value determined by our method, E m7 =-158mV, is precise, reproducible, and consistent with previously reported values. Our small-volume potentiometric titration method will facilitate detailed investigations of EPR-active centres in non-abundant and refractory proteins that can only be prepared in small quantities. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Electromagnetic properties of carbonyl iron and their microwave ...

    Indian Academy of Sciences (India)

    Administrator

    The aim of this paper is to develop a novel thin micro- wave absorber with good absorbing performance in wide bandwidth and lightweight. So we investigated the micro- wave absorbing characterization of silicone rubber using carbonyl iron as filler. Carbonyl iron can be widely used in the field of electromagnetic shielding ...

  9. Bifunctional dendrons for multiple carbohydrate presentation via carbonyl chemistry

    Directory of Open Access Journals (Sweden)

    Davide Bini

    2014-07-01

    Full Text Available The synthesis of new dendrons of the generations 0, 1 and 2 with a double bond at the focal point and a carbonyl group at the termini has been carried out. The carbonyl group has been exploited for the multivalent conjugation to a sample saccharide by reductive amination and alkoxyamine conjugation.

  10. Synthesis and detection of a seaborgium carbonyl complex

    NARCIS (Netherlands)

    Even, J.; Yakushev, A.; Duellmann, Ch E.; Haba, H.; Asai, M.; Sato, T. K.; Brand, H.; Di Nitto, A.; Eichler, R.; Fan, F. L.; Hartmann, W.; Huang, M.; Jaeger, E.; Kaji, D.; Kanaya, J.; Kaneya, Y.; Khuyagbaatar, J.; Kindler, B.; Kratz, J. V.; Krier, J.; Kudou, Y.; Kurz, N.; Lommel, B.; Miyashita, S.; Morimoto, K.; Morita, K.; Murakami, M.; Nagame, Y.; Nitsche, H.; Ooe, K.; Qin, Z.; Schaedel, M.; Steiner, J.; Sumita, T.; Takeyama, M.; Tanaka, K.; Toyoshima, A.; Tsukada, K.; Tuerler, A.; Usoltsev, I.; Wakabayashi, Y.; Wang, Y.; Wiehl, N.; Yamaki, S.

    2014-01-01

    Experimental investigations of transactinoide elements provide benchmark results for chemical theory and probe the predictive power of trends in the periodic table. So far, in gas-phase chemical reactions, simple inorganic compounds with the transactinoide in its highest oxidation state have been

  11. Carbonyl-Olefin Exchange Reaction: Present State and Outlook

    Science.gov (United States)

    Kalinova, Radostina; Jossifov, Christo

    The carbonyl-olefin exchange reaction (COER) is a new reaction between carbonyl group and olefin double bond, which has a formal similarity with the olefin metathesis (OM) - one carbon atom in the latter is replaced with an oxygen atom. Till now the new reaction is performed successfully only when the two functional groups (carbonyl group and olefin double bond) are in one molecule and are conjugated. The α, β-unsaturated carbonyl compounds (substituted propenones) are the compounds with such a structure. They polymerize giving substituted polyacetylenes. The chain propagation step of this polymerization is in fact the COER. The question arises: is it possible the COER to take place when the two functional groups are not in one molecule and are not conjugated, and could this reaction became an alternative of the existing carbonyl olefination reactions?

  12. Optimized biotin-hydrazide enrichment and mass spectrometry analysis of peptide carbonyls

    DEFF Research Database (Denmark)

    Havelund, Jesper F.; Wojdyla, K; Jensen, O. N.

    Irreversible cell damage through protein carbonylation is the result of reaction with reactive oxygen species (ROS) and has been coupled to many diseases. The precise molecular consequences of protein carbonylation, however, are still not clear. The localization of the carbonylated amino acid is ...... modifications are isobaric to carbonylation and it is often challenging to detect the weaker signal from carbonylated peptides necessitating enrichment step. We here present an optimized method for the enrichment of carbonylated peptides....

  13. Catalyst Initiation in the Oscillatory Carbonylation Reaction

    Directory of Open Access Journals (Sweden)

    Katarina Novakovic

    2011-01-01

    Full Text Available Palladium(II iodide is used as a catalyst in the phenylacetylene oxidative carbonylation reaction that has demonstrated oscillatory behaviour in both pH and heat of reaction. In an attempt to extract the reaction network responsible for the oscillatory nature of this reaction, the system was divided into smaller parts and they were studied. This paper focuses on understanding the reaction network responsible for the initial reactions of palladium(II iodide within this oscillatory reaction. The species researched include methanol, palladium(II iodide, potassium iodide, and carbon monoxide. Several chemical reactions were considered and applied in a modelling study. The study revealed the significant role played by traces of water contained in the standard HPLC grade methanol used.

  14. Functional characterization of diverse ring-hydroxylating oxygenases and induction of complex aromatic catabolic gene clusters in Sphingobium sp. PNB

    Directory of Open Access Journals (Sweden)

    Pratick Khara

    2014-01-01

    Full Text Available Sphingobium sp. PNB, like other sphingomonads, has multiple ring-hydroxylating oxygenase (RHO genes. Three different fosmid clones have been sequenced to identify the putative genes responsible for the degradation of various aromatics in this bacterial strain. Comparison of the map of the catabolic genes with that of different sphingomonads revealed a similar arrangement of gene clusters that harbors seven sets of RHO terminal components and a sole set of electron transport (ET proteins. The presence of distinctly conserved amino acid residues in ferredoxin and in silico molecular docking analyses of ferredoxin with the well characterized terminal oxygenase components indicated the structural uniqueness of the ET component in sphingomonads. The predicted substrate specificities, derived from the phylogenetic relationship of each of the RHOs, were examined based on transformation of putative substrates and their structural homologs by the recombinant strains expressing each of the oxygenases and the sole set of available ET proteins. The RHO AhdA1bA2b was functionally characterized for the first time and was found to be capable of transforming ethylbenzene, propylbenzene, cumene, p-cymene and biphenyl, in addition to a number of polycyclic aromatic hydrocarbons. Overexpression of aromatic catabolic genes in strain PNB, revealed by real-time PCR analyses, is a way forward to understand the complex regulation of degradative genes in sphingomonads.

  15. Composition tunable cobalt–nickel and cobalt–iron alloy nanoparticles below 10 nm synthesized using acetonated cobalt carbonyl

    International Nuclear Information System (INIS)

    Schooneveld, Matti M. van; Campos-Cuerva, Carlos; Pet, Jeroen; Meeldijk, Johannes D.; Rijssel, Jos van; Meijerink, Andries; Erné, Ben H.; Groot, Frank M. F. de

    2012-01-01

    A general organometallic route has been developed to synthesize Co x Ni 1−x and Co x Fe 1−x alloy nanoparticles with a fully tunable composition and a size of 4–10 nm with high yield. In contrast to previously reported synthesis methods using dicobalt octacarbonyl (Co 2 (CO) 8 ), here the cobalt–cobalt bond in the carbonyl complex is first broken with anhydrous acetone. The acetonated compound, in the presence of iron carbonyl or nickel acetylacetonate, is necessary to obtain small composition tunable alloys. This new route and insights will provide guidelines for the wet-chemical synthesis of yet unmade bimetallic alloy nanoparticles.

  16. Deficiency of the iron-sulfur clusters of mitochondrial reduced nicotinamide-adenine dinucleotide-ubiquinone oxidoreductase (complex I) in an infant with congenital lactic acidosis.

    Science.gov (United States)

    Moreadith, R W; Batshaw, M L; Ohnishi, T; Kerr, D; Knox, B; Jackson, D; Hruban, R; Olson, J; Reynafarje, B; Lehninger, A L

    1984-09-01

    We report the case of an infant with hypoglycemia, progressive lactic acidosis, an increased serum lactate/pyruvate ratio, and elevated plasma alanine, who had a moderate to profound decrease in the ability of mitochondria from four organs to oxidize pyruvate, malate plus glutamate, citrate, and other NAD+-linked respiratory substrates. The capacity to oxidize the flavin adenine dinucleotide-linked substrate, succinate, was normal. The most pronounced deficiency was in skeletal muscle, the least in kidney mitochondria. Enzymatic assays on isolated mitochondria ruled out defects in complexes II, III, and IV of the respiratory chain. Further studies showed that the defect was localized in the inner membrane mitochondrial NADH-ubiquinone oxidoreductase (complex I). When ferricyanide was used as an artificial electron acceptor, complex I activity was normal, indicating that electrons from NADH could reduce the flavin mononucleotide cofactor. However, electron paramagnetic resonance spectroscopy performed on liver submitochondrial particles showed an almost total loss of the iron-sulfur clusters characteristic of complex I, whereas normal signals were noted for other mitochondrial iron-sulfur clusters. This infant is presented as the first reported case of congenital lactic acidosis caused by a deficiency of the iron-sulfur clusters of complex I of the mitochondrial electron transport chain.

  17. Is the largest aqueous gold cluster a superatom complex? Electronic structure & optical response of the structurally determined Au146(p-MBA)57.

    Science.gov (United States)

    López-Lozano, Xóchitl; Plascencia-Villa, G; Calero, G; Whetten, R L; Weissker, Hans-Christian

    2017-12-07

    The new water-soluble gold cluster Au 146 (p-MBA) 57 , the structure of which has been recently determined at sub-atomic resolution by Vergara et al., is the largest aqueous gold cluster ever structurally determined and likewise the smallest cluster with a stacking fault. The core presents a twinned truncated octahedron, while additional peripheral gold atoms follow a C 2 rotational symmetry. According to the usual counting rules of the superatom complex (SAC) model, the compound attains a number of 92 SAC electrons if the overall net charge is 3- (three additional electrons). As this is the number of electrons required for a major shell closing, the question arises of whether Au 146 (p-MBA) 57 should be regarded as a superatom complex. Starting from the experimental coordinates we have analyzed the structure using density-functional theory. The optimized (relaxed) structure retains all the connectivity of the experimental coordinates, while removing much of its irregularities in interatomic distances, thereby enhancing the C 2 -symmetry feature. On analyzing the angular-momentum-projected states, we show that, despite a small gap, the electronic structure does not exhibit SAC model character. In addition, optical absorption spectra are found to be relatively smooth compared to the example of the Au 144 (SR) 60 cluster. The Au 146 (SR) 57 does not derive its stability from SAC character; it cannot be considered as a superatom complex.

  18. Clusters and how to make it work : Cluster Strategy Toolkit

    NARCIS (Netherlands)

    Manickam, Anu; van Berkel, Karel

    2014-01-01

    Clusters are the magic answer to regional economic development. Firms in clusters are more innovative; cluster policy dominates EU policy; ‘top-sectors’ and excellence are the choice of national policy makers; clusters are ‘in’. But, clusters are complex, clusters are ‘messy’; there is no clear

  19. High throughput assay for evaluation of reactive carbonyl scavenging capacity.

    Science.gov (United States)

    Vidal, N; Cavaille, J P; Graziani, F; Robin, M; Ouari, O; Pietri, S; Stocker, P

    2014-01-01

    Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

  20. High throughput assay for evaluation of reactive carbonyl scavenging capacity

    Directory of Open Access Journals (Sweden)

    N. Vidal

    2014-01-01

    Full Text Available Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

  1. 16th Carbonyl Metabolism Meeting: from enzymology to genomics

    Directory of Open Access Journals (Sweden)

    Maser Edmund

    2012-12-01

    Full Text Available Abstract The 16th International Meeting on the Enzymology and Molecular Biology of Carbonyl Metabolism, Castle of Ploen (Schleswig-Holstein, Germany, July 10–15, 2012, covered all aspects of NAD(P-dependent oxido-reductases that are involved in the general metabolism of xenobiotic and physiological carbonyl compounds. Starting 30 years ago with enzyme purification, structure elucidation and enzyme kinetics, the Carbonyl Society members have meanwhile established internationally recognized enzyme nomenclature systems and now consider aspects of enzyme genomics and enzyme evolution along with their roles in diseases. The 16th international meeting included lectures from international speakers from all over the world.

  2. Characterization of Carbonyl Compounds in the Ambient Air of an Industrial City in Korea

    Directory of Open Access Journals (Sweden)

    Sung-Ok Baek

    2011-01-01

    Full Text Available The purpose of this study was to characterize spatial and temporal variations of carbonyl compounds in Gumi city, where a number of large electronic-industrial complexes are located. Carbonyl samples were collected at five sites in the Gumi area: three industrial, one commercial, and one residential area. Sampling was carried out throughout a year from December 2003 to November 2004. At one industrial site, samples were taken every six days, while those of the other sites were for seven consecutive days in every season. Each sample was collected for 150 minutes and at intervals of three times a day (morning, afternoon, and evening. A total of 476 samples were analyzed to determine 15 carbonyl compounds by the USEPA TO-11A (DNPH-cartridge/HPLC method. In general, acetaldehyde appeared to be the most abundant compound, followed by formaldehyde, and acetone+acrolein. Mean concentrations of acetaldehyde were two to three times higher in the industrial sites than in the other sites, with its maximum of 77.7 ppb. In contrast, ambient levels of formaldehyde did not show any significant difference between the industrial and non-industrial groups. Its concentrations peaked in summer probably due to the enhanced volatilization and photochemical reactivity. These results indicate significant emission sources of acetaldehyde in the Gumi industrial complexes. Mean concentrations of organic solvents (such as acetone+acrolein and methyl ethyl ketone were also significantly high in industrial areas. In conclusion, major sources of carbonyl compounds, including acetaldehyde, are strongly associated with industrial activities in the Gumi city area.

  3. Reactions of laser-ablated Co, Rh, and Ir with CO: Infrared spectra and density functional calculations of the metal carbonyl molecules, cations and anions in solid neon

    International Nuclear Information System (INIS)

    Zhou, M.; Andrews, L.

    1999-01-01

    Laser ablation produces metal atoms, cations, and electrons for reaction with CO during condensation in excess neon at 4 K. Infrared spectra are observed for the metal carbonyls, cations, and anions, which are identified from isotopic shifts ( 13 CO, C 18 O) and splittings using mixed isotopic precursors. Density functional calculations with pseudopotentials for Rh and Ir predict the observed carbonyl stretching frequencies within 1--2%. This characterization of the simple RhCO + , RhCO, and RhCO - (and Ir) species over a 350 cm -1 range provides a scale for comparison of larger catalytically active Rh and Ir carbonyl complexes in solution and on surfaces to estimate charge on the metal center. This work provides the first spectroscopic characterization of Rh and Ir carbonyl cations and anions except for the stable tetracarbonyl anions in solution

  4. Synthesis and structures of bimetallic titanium and chromium carbene complexes of the type Cp/sub 2/Ti(Cl)O(CH/sub 3/)CCr(CO)/sub 5/

    Energy Technology Data Exchange (ETDEWEB)

    Anslyn, E.V.; Santarsiero, B.D.; Grubbs, R.H.

    1988-10-01

    Insertion reactions are some of the most common and important reactions in organometallic chemistry. Aside from being mechanistically interesting, they have proven useful in organic synthesis and have been postulated in catalytic cycles. A subset of the broad group of insertion reactions is the insertion of carbon monoxides of group VIB metal carbonyl complexes into early-transition-metal alkyl, aryl and hydride bonds. Although the coupling of metal alkylidenes with metal carbonyl complexes is rare in monometallic systems, such coupling is frequently postulated in heterogeneous Fischer-Tropsch systems to yield surface-bound ketene fragments. The formation of bound ketene in bimetallic and cluster complexes has been documented. Herein the authors report the coupling of titanocene methylidene with Cr(CO)/sub 6/ to yield a titanocene ketene complex.

  5. Complexes of DNA bases and Watson-Crick base pairs interaction with neutral silver Agn (n = 8, 10, 12) clusters: a DFT and TDDFT study.

    Science.gov (United States)

    Srivastava, Ruby

    2018-03-01

    We study the binding of the neutral Ag n (n = 8, 10, 12) to the DNA base-adenine (A), guanine (G) and Watson-Crick -adenine-thymine, guanine-cytosine pairs. Geometries of complexes were optimized at the DFT level using the hybrid B3LYP functional. LANL2DZ effective core potential was used for silver and 6-31 + G ** was used for all other atoms. NBO charges were analyzed using the Natural population analysis. The absorption properties of Ag n -A,G/WC complexes were also studied using time-dependent density functional theory. The absorption spectra for these complexes show wavelength in the visible region. It was revealed that silver clusters interact more strongly with WC pairs than with isolated DNA complexes. Furthermore, it was found that the electronic charge transferred from silver to isolated DNA clusters are less than the electronic charge transferred from silver to the Ag n -WC complexes. The vertical ionization potential, vertical electron affinity, hardness, and electrophilicity index of Ag n -DNA/WC complexes have also been discussed.

  6. Interactions of iron-bound frataxin with ISCU and ferredoxin on the cysteine desulfurase complex leading to Fe-S cluster assembly.

    Science.gov (United States)

    Cai, Kai; Frederick, Ronnie O; Tonelli, Marco; Markley, John L

    2018-06-01

    Frataxin (FXN) is involved in mitochondrial iron‑sulfur (Fe-S) cluster biogenesis and serves to accelerate Fe-S cluster formation. FXN deficiency is associated with Friedreich ataxia, a neurodegenerative disease. We have used a combination of isothermal titration calorimetry and multinuclear NMR spectroscopy to investigate interactions among the components of the biological machine that carries out the assembly of iron‑sulfur clusters in human mitochondria. Our results show that FXN tightly binds a single Fe 2+ but not Fe 3+ . While FXN (with or without bound Fe 2+ ) does not bind the scaffold protein ISCU directly, the two proteins interact mutually when each is bound to the cysteine desulfurase complex ([NFS1] 2 :[ISD11] 2 :[Acp] 2 ), abbreviated as (NIA) 2 , where "N" represents the cysteine desulfurase (NFS1), "I" represents the accessory protein (ISD11), and "A" represents acyl carrier protein (Acp). FXN binds (NIA) 2 weakly in the absence of ISCU but more strongly in its presence. Fe 2+ -FXN binds to the (NIA) 2 -ISCU 2 complex without release of iron. However, upon the addition of both l-cysteine and a reductant (either reduced FDX2 or DTT), Fe 2+ is released from FXN as consistent with Fe 2+ -FXN being the proximal source of iron for Fe-S cluster assembly. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Instrument for Airborne Measurement of Carbonyl Sulfide, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Southwest Sciences proposes to develop small, low power instrumentation for the real-time direct measurement of carbonyl sulfide (OCS) in the atmosphere, especially...

  8. Instrument for Airborne Measurement of Carbonyl Sulfide, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase II SBIR program, Southwest Sciences will continue the development of small, low power instrumentation for real-time direct measurement of carbonyl...

  9. Degradation of carbonyl hydroperoxides in the atmosphere and in combustion

    KAUST Repository

    Xing, Lili; Bao, Junwei Lucas; Wang, Zhandong; Zhang, Feng; Truhlar, Donald G.

    2017-01-01

    Oxygenates with carbonyl and hydroperoxy functional groups are important intermediates that are generated during the autooxidation of organic compounds in the atmosphere and during the autoignition of transport fuels. In the troposphere

  10. DNA damage by carbonyl stress in human skin cells

    International Nuclear Information System (INIS)

    Roberts, Michael J.; Wondrak, Georg T.; Laurean, Daniel Cervantes; Jacobson, Myron K.; Jacobson, Elaine L.

    2003-01-01

    Reactive carbonyl species (RCS) are potent mediators of cellular carbonyl stress originating from endogenous chemical processes such as lipid peroxidation and glycation. Skin deterioration as observed in photoaging and diabetes has been linked to accumulative protein damage from glycation, but the effects of carbonyl stress on skin cell genomic integrity are ill defined. In this study, the genotoxic effects of acute carbonyl stress on HaCaT keratinocytes and CF3 fibroblasts were assessed. Administration of the α-dicarbonyl compounds glyoxal and methylglyoxal as physiologically relevant RCS inhibited skin cell proliferation, led to intra-cellular protein glycation as evidenced by the accumulation of N ε -(carboxymethyl)-L-lysine (CML) in histones, and caused extensive DNA strand cleavage as assessed by the comet assay. These effects were prevented by treatment with the carbonyl scavenger D-penicillamine. Both glyoxal and methylglyoxal damaged DNA in intact cells. Glyoxal caused DNA strand breaks while methylglyoxal produced extensive DNA-protein cross-linking as evidenced by pronounced nuclear condensation and total suppression of comet formation. Glycation by glyoxal and methylglyoxal resulted in histone cross-linking in vitro and induced oxygen-dependent cleavage of plasmid DNA, which was partly suppressed by the hydroxyl scavenger mannitol. We suggest that a chemical mechanism of cellular DNA damage by carbonyl stress occurs in which histone glycoxidation is followed by reactive oxygen induced DNA stand breaks. The genotoxic potential of RCS in cultured skin cells and its suppression by a carbonyl scavenger as described in this study have implications for skin damage and carcinogenesis and its prevention by agents selective for carbonyl stress

  11. DNA damage by carbonyl stress in human skin cells

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Michael J.; Wondrak, Georg T.; Laurean, Daniel Cervantes; Jacobson, Myron K.; Jacobson, Elaine L

    2003-01-28

    Reactive carbonyl species (RCS) are potent mediators of cellular carbonyl stress originating from endogenous chemical processes such as lipid peroxidation and glycation. Skin deterioration as observed in photoaging and diabetes has been linked to accumulative protein damage from glycation, but the effects of carbonyl stress on skin cell genomic integrity are ill defined. In this study, the genotoxic effects of acute carbonyl stress on HaCaT keratinocytes and CF3 fibroblasts were assessed. Administration of the {alpha}-dicarbonyl compounds glyoxal and methylglyoxal as physiologically relevant RCS inhibited skin cell proliferation, led to intra-cellular protein glycation as evidenced by the accumulation of N{sup {epsilon}}-(carboxymethyl)-L-lysine (CML) in histones, and caused extensive DNA strand cleavage as assessed by the comet assay. These effects were prevented by treatment with the carbonyl scavenger D-penicillamine. Both glyoxal and methylglyoxal damaged DNA in intact cells. Glyoxal caused DNA strand breaks while methylglyoxal produced extensive DNA-protein cross-linking as evidenced by pronounced nuclear condensation and total suppression of comet formation. Glycation by glyoxal and methylglyoxal resulted in histone cross-linking in vitro and induced oxygen-dependent cleavage of plasmid DNA, which was partly suppressed by the hydroxyl scavenger mannitol. We suggest that a chemical mechanism of cellular DNA damage by carbonyl stress occurs in which histone glycoxidation is followed by reactive oxygen induced DNA stand breaks. The genotoxic potential of RCS in cultured skin cells and its suppression by a carbonyl scavenger as described in this study have implications for skin damage and carcinogenesis and its prevention by agents selective for carbonyl stress.

  12. Propheromones that release pheromonal carbonyl compounds in light.

    Science.gov (United States)

    Liu, X; Macaulay, E D; Pickett, J A

    1984-05-01

    Pheromonal carbonyl compounds; (Z)-11-hexadecanal, (E)-citral, and 2-heptanone were treated with six alcohols to give acetals or ketals, some of which acted as propheromones by releasing the pheromonal carbonyl compounds in ultraviolet or simulated sunlight. Highest yields of pheromone were obtained from adducts prepared witho-nitrobenzyl alcohol ando-nitrophenylethane-1,2-diol. Adducts from (Z)-11-hexadecenal and these two alcohols were employed in lures to catch diamondback moths,Plutella xylostella (L.).

  13. Dansyl labeling and bidimensional mass spectrometry to investigate protein carbonylation.

    Science.gov (United States)

    Palmese, Angelo; De Rosa, Chiara; Marino, Gennaro; Amoresano, Angela

    2011-01-15

    Carbonylation is a non-enzymatic irreversible post-translational modification. The adduction of carbonyl groups to proteins is due to the presence of excess of ROS in cells. Carbonylation of specific amino acid side chains is one of the most abundant consequences of oxidative stress; therefore, the determination of carbonyl groups content in proteins is regarded as a reliable way to estimate the cellular damage caused by oxidative stress. This paper reports a novel RIGhT (Reporter Ion Generating Tag) (A. Amoresano, G. Monti, C. Cirulli, G. Marino. Rapid Commun. Mass Spectrom. 2006, 20, 1400) approach for selective labeling of carbonyl groups in proteins using dansylhydrazide, coupled with selective analysis by bidimensional mass spectrometry. We first applied this approach to ribonuclease A and lysozyme as model proteins. According to the so-called 'gel-free procedures', the analysis is carried out at the level of peptides following tryptic digest of the whole protein mixture. Modified RNaseA was analyzed in combined MS(2) and MS(3) scan mode, to specifically select the dansylated species taking advantage of the dansyl-specific fragmentation pathways. This combination allowed us to obtain a significant increase in signal/noise ratio and a significant increase in sensitivity of analysis, due to the reduction of duty cycle of the mass spectrometer. The unique signal obtained was correlated to peptide 1-10 of RNaseA carbonylated and labeled by dansylhydrazide. This strategy represents the first method leading to the direct identification of the carbonylation sites in proteins, thus indicating the feasibility of this strategy to investigate protein carbonylation in a proteomic approach. Copyright © 2010 John Wiley & Sons, Ltd.

  14. Selective transformation of carbonyl ligands to organic molecules. Progress report, September 1, 1989--November 14, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, A.R.

    1992-05-12

    Studies on the carbonylation of ({eta}{sup 5}-indenyl)(L)(CO)Ru-R complexes (L = CO, PPh{sub 3}; R = CH{sub 2}OMe, CH{sub 3}) have been completed. Particularly noteworthy is that the methoxymethyl complexes readily transform to their acyl derivatives under mild conditions that leave their iron congeners inert towards CO. Surprisingly, even ({eta}{sup 5}-indenyl)(PPh{sub 3}){sub 2}Ru-CH{sub 3} carbonylates and gives ({eta}{sup 5}-indenyl)(PPh{sub 3})(CO)Ru-C(O)CH{sub 3}. Mechanistic studies on the ``non catalyzed`` hydrosilation of the manganese acyls (CO){sub 5}Mn-C(O)CH{sub 2}R (R = H, OCH{sub 3}, CH{sub 3}) with Et{sub 3}SiH and of cobalt acetyls (CO){sub 3}(PR{sub 3})CoC(O)CH{sub 3} with several monohydrosilanes have been completed. The cobalt acetyls cleanly give ethoxysilanes (not acetaldehyde), and the manganese acyls provide {alpha}-siloxyvinyl complexes Z-(CO){sub 5}Mn-C(OSiEt{sub 3})=CHR (R = H, CH{sub 3}, OCH{sub 3}). Carbonylation and protolytic cleavage of the latter generate pyruvoyl complexes (CO){sub 5}Mn-COCOR (R = CH{sub 3}, CH{sub 2}CH{sub 3}), formally the products of net ``double carbonylation`` sequences. Studies in progress are concerned with how manganese complexes as diverse as (CO){sub 5}Mn-Y [Y = C(O)R, R, BR - but not SiMe{sub 3} or Mn(CO){sub 5}] and ({eta}{sup 3}-C{sub 3}H{sub 5})Mn(CO){sub 2}L [but not CpMn(CO){sub 3} or CpMn(CO){sub 2}({eta}{sup 2}HSiR{sub 3})] function as efficient hydrosilation catalysts towards Cp(CO){sub 2}FeC(O)CH{sub 3}, for example. These reactions cleanly afford fully characterized {alpha}-siloxyethyl complexes Fp-CH(OSiR{sub 3})CH{sub 3} under conditions where typically Rh(1) hydrosilation catalysts are inactive. Several of these manganese complexes also catalytically hydrosilate organic esters, including lactones, to their ethers R-CH{sub 2}OR; these novel ester reductions occur quantitatively at room temperature and appear to be general in scope.

  15. New method to determine the total carbonyl functional group content in extractable particulate organic matter by tandem mass spectrometry.

    Science.gov (United States)

    Dron, J; Zheng, W; Marchand, N; Wortham, H

    2008-08-01

    A functional group analysis method was developed to determine the quantitative content of carbonyl functional groups in atmospheric particulate organic matter (POM) using constant neutral loss scanning-tandem mass spectrometry (CNLS-MS/MS). The neutral loss method consists in monitoring the loss of a neutral fragment produced by the fragmentation of a precursor ion in a collision cell. The only ions detected are the daughter ions resulting from the loss of the neutral fragment under study. Then, scanning the loss of a neutral fragment characteristic of a functional group enables the selective detection of the compounds bearing the chemical function under study within a complex mixture. The selective detection of carbonyl functional groups was achieved after derivatization with pentafluorophenylhydrazine (PFPH) by monitoring the neutral loss of C(6)F(5)N (181 amu), which was characteristic of a large panel of derivatized carbonyl compounds. The method was tested on 25 reference mixtures of different composition, all containing 24 carbonyl compounds at randomly determined concentrations. The repeatability and calibration tests were satisfying as they resulted in a relative standard deviation below 5% and a linear range between 0.01 and 0.65 mM with a calculated detection limit of 0.0035 mM. Also, the relative deviation induced by changing the composition of the mixture while keeping the total concentration of carbonyl functional groups constant was less than 20%. These reliability experiments demonstrate the high robustness of the developed procedure for accurate carbonyl functional group measurement, which was applied to atmospheric POM samples. Copyright (c) 2008 John Wiley & Sons, Ltd.

  16. Catalytic performance of heterogeneous Rh/C3N4 for the carbonylation of methanol

    Science.gov (United States)

    Budiman, Anatta Wahyu; Choi, Myoung Jae; Nur, Adrian

    2018-02-01

    The excess of water in homogeneous the carbonylation of methanol system could increase the amount of by-products formed through water-gas shift reaction and could accelerate the rusting of equipment. Many scientists tried to decrease the content of water in the carbonylation of methanol system by using lithium and iodide promoter that results a moderate catalytic activity in the water content at 2wt%. The heterogenized catalyst offers several distinct advantages such as it was enables increased catalyst concentration in the reaction mixture, which is directly proportional to acetic acid production rate, without the addition of an alkali iodide salt promoter. The heterogeneous catalyst also results in reduced by-product formation. This study is aimed to produce a novel catalyst (Rh/C3N4) with a high selectivity of acetic acid in a relatively lower water and halide content. This novel catalyst performs high conversion and selectivity of acetic acid as the result of the strong ionic bonding of melamine and rhodium complex species that was caused by the presence of methyl iodide species. The CO2 in feed gas significantly decreases the catalytic activity of Rh-melamine because of its inert characteristics. The kinetic test was performed as that the first order kinetic equation. The kinetic tests revealed the reaction route of the the carbonylation of methanol in this system was performed trough the methyl acetate.

  17. Vapor phase carbonylation of dimethyl ether and methyl acetate with supported transition metal catalysts

    International Nuclear Information System (INIS)

    Shikada, T.; Fujimoto, K.; Tominaga, H.O.

    1986-01-01

    The synthesis of acetic acid (AcOH) from methanol (MeOH) and carbon monoxide has been performed industrially in the liquid phase using a rhodium complex catalyst and an iodide promoter. The selectivity to AcOH is more than 99% under mild conditions (175 0 C, 28 atm). The homogeneous rhodium catalyst has been also effective for the synthesis of acetic anhydride (Ac 2 O) by carbonylation of dimethyl ether (DME) or methyl acetate (AcOMe). However, rhodium is one of the most expensive metals and its proved reserves are quite limited. It is highly desired, therefore, to develop a new catalyst as a substitute for rhodium. The authors have already reported that nickel supported on active carbon exhibits an excellent activity for the vapor phase carbonylation of MeOh in the presence of iodide promoter and under moderately pressurized conditions. In addition, corrosive attack on reactors by iodide compounds is expected to be negligible in the vapor phase system. In the present work, vapor phase carbonylation of DME and AcOMe on nickel-active carbon (Ni/A.C.) and molybdenum-active carbon (Mo/A.C.) catalysts was studied

  18. Updated clusters of orthologous genes for Archaea: a complex ancestor of the Archaea and the byways of horizontal gene transfer

    Directory of Open Access Journals (Sweden)

    Wolf Yuri I

    2012-12-01

    Full Text Available Abstract Background Collections of Clusters of Orthologous Genes (COGs provide indispensable tools for comparative genomic analysis, evolutionary reconstruction and functional annotation of new genomes. Initially, COGs were made for all complete genomes of cellular life forms that were available at the time. However, with the accumulation of thousands of complete genomes, construction of a comprehensive COG set has become extremely computationally demanding and prone to error propagation, necessitating the switch to taxon-specific COG collections. Previously, we reported the collection of COGs for 41 genomes of Archaea (arCOGs. Here we present a major update of the arCOGs and describe evolutionary reconstructions to reveal general trends in the evolution of Archaea. Results The updated version of the arCOG database incorporates 91% of the pangenome of 120 archaea (251,032 protein-coding genes altogether into 10,335 arCOGs. Using this new set of arCOGs, we performed maximum likelihood reconstruction of the genome content of archaeal ancestral forms and gene gain and loss events in archaeal evolution. This reconstruction shows that the last Common Ancestor of the extant Archaea was an organism of greater complexity than most of the extant archaea, probably with over 2,500 protein-coding genes. The subsequent evolution of almost all archaeal lineages was apparently dominated by gene loss resulting in genome streamlining. Overall, in the evolution of Archaea as well as a representative set of bacteria that was similarly analyzed for comparison, gene losses are estimated to outnumber gene gains at least 4 to 1. Analysis of specific patterns of gene gain in Archaea shows that, although some groups, in particular Halobacteria, acquire substantially more genes than others, on the whole, gene exchange between major groups of Archaea appears to be largely random, with no major ‘highways’ of horizontal gene transfer. Conclusions The updated collection

  19. New Ir Bis-Carbonyl Precursor for Water Oxidation Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Daria L. [Department of Chemistry, Yale University, 225; Beltrán-Suito, Rodrigo [Department of Chemistry, Yale University, 225; Thomsen, Julianne M. [Department of Chemistry, Yale University, 225; Hashmi, Sara M. [Department of Chemical and Environmental; Materna, Kelly L. [Department of Chemistry, Yale University, 225; Sheehan, Stafford W. [Catalytic Innovations LLC, 70 Crandall; Mercado, Brandon Q. [Department of Chemistry, Yale University, 225; Brudvig, Gary W. [Department of Chemistry, Yale University, 225; Crabtree, Robert H. [Department of Chemistry, Yale University, 225

    2016-02-05

    This paper introduces IrI(CO)2(pyalc) (pyalc = (2-pyridyl)-2-propanoate) as an atom-efficient precursor for Ir-based homogeneous oxidation catalysis. This compound was chosen to simplify analysis of the water oxidation catalyst species formed by the previously reported Cp*IrIII(pyalc)OH water oxidation precatalyst. Here, we present a comparative study on the chemical and catalytic properties of these two precursors. Previous studies show that oxidative activation of Cp*Ir-based precursors with NaIO4 results in formation of a blue IrIV species. This activation is concomitant with the loss of the placeholder Cp* ligand which oxidatively degrades to form acetic acid, iodate, and other obligatory byproducts. The activation process requires substantial amounts of primary oxidant, and the degradation products complicate analysis of the resulting IrIV species. The species formed from oxidation of the Ir(CO)2(pyalc) precursor, on the other hand, lacks these degradation products (the CO ligands are easily lost upon oxidation) which allows for more detailed examination of the resulting Ir(pyalc) active species both catalytically and spectroscopically, although complete structural analysis is still elusive. Once Ir(CO)2(pyalc) is activated, the system requires acetic acid or acetate to prevent the formation of nanoparticles. Investigation of the activated bis-carbonyl complex also suggests several Ir(pyalc) isomers may exist in solution. By 1H NMR, activated Ir(CO)2(pyalc) has fewer isomers than activated Cp*Ir complexes, allowing for advanced characterization. Future research in this direction is expected to contribute to a better structural understanding of the active species. A diol crystallization agent was needed for the structure determination of 3.

  20. Ozone Effects on Protein Carbonyl Content in the Frontal ...

    Science.gov (United States)

    Oxidative stress (OS) plays an important role in susceptibility and disease in old age. Understanding age-related susceptibility is a critical part of community-based human health risk assessment of chemical exposures. There is growing concern over a common air pollutant, ozone (03), and adverse health effects including dysfunction of the pulmonary, cardiac, and nervous systems. The objective of this study was to test whether OS plays a role in the adverse effects caused by 03 exposure, and if so, if effects were age-dependent. We selected protein carbonyl as an indicator of OS because carbonyl content of cells is a useful indicator of oxidative protein damage and has been linked to chemical-induced adverse effects. Male Brown Norway rats (4, 12, and 24 months) were exposed to 03 (0,0.25 or 1 ppm) via inhalation for 6 h/day, 2 days per week for 13 weeks. Frontal cortex (FC) and cerebellum (CB) were dissected, quick frozen on dry ice, and stored at -80°C. Protein carbonyls were assayed using commercial kits. Hydrogen peroxide, a positive control, increased protein carbonyls in cortical tissue in vitro in a concentration-dependent manner. Significant effects of age on protein carbonyls in FC and a significant effect of age and 03 dose on protein carbonyls in CB were observed. In control rats, there was an age-dependent increase in protein carbonyls indicating increased OS in 12 and 24 month old rats compared to 4 month old rats. Although 03 increase

  1. Evolution of the C-Type Lectin-Like Receptor Genes of the DECTIN-1 Cluster in the NK Gene Complex

    Directory of Open Access Journals (Sweden)

    Susanne Sattler

    2012-01-01

    Full Text Available Pattern recognition receptors are crucial in initiating and shaping innate and adaptive immune responses and often belong to families of structurally and evolutionarily related proteins. The human C-type lectin-like receptors encoded in the DECTIN-1 cluster within the NK gene complex contain prominent receptors with pattern recognition function, such as DECTIN-1 and LOX-1. All members of this cluster share significant homology and are considered to have arisen from subsequent gene duplications. Recent developments in sequencing and the availability of comprehensive sequence data comprising many species showed that the receptors of the DECTIN-1 cluster are not only homologous to each other but also highly conserved between species. Even in Caenorhabditis elegans, genes displaying homology to the mammalian C-type lectin-like receptors have been detected. In this paper, we conduct a comprehensive phylogenetic survey and give an up-to-date overview of the currently available data on the evolutionary emergence of the DECTIN-1 cluster genes.

  2. Clustering of near clusters versus cluster compactness

    International Nuclear Information System (INIS)

    Yu Gao; Yipeng Jing

    1989-01-01

    The clustering properties of near Zwicky clusters are studied by using the two-point angular correlation function. The angular correlation functions for compact and medium compact clusters, for open clusters, and for all near Zwicky clusters are estimated. The results show much stronger clustering for compact and medium compact clusters than for open clusters, and that open clusters have nearly the same clustering strength as galaxies. A detailed study of the compactness-dependence of correlation function strength is worth investigating. (author)

  3. The Limited Role of Number of Nested Syntactic Dependencies in Accounting for Processing Cost: Evidence from German Simplex and Complex Verbal Clusters

    Directory of Open Access Journals (Sweden)

    Markus Bader

    2018-01-01

    Full Text Available This paper presents three acceptability experiments investigating German verb-final clauses in order to explore possible sources of sentence complexity during human parsing. The point of departure was De Vries et al.'s (2011 generalization that sentences with three or more crossed or nested dependencies are too complex for being processed by the human parsing mechanism without difficulties. This generalization is partially based on findings from Bach et al. (1986 concerning the acceptability of complex verb clusters in German and Dutch. The first experiment tests this generalization by comparing two sentence types: (i sentences with three nested dependencies within a single clause that contains three verbs in a complex verb cluster; (ii sentences with four nested dependencies distributed across two embedded clauses, one center-embedded within the other, each containing a two-verb cluster. The results show that sentences with four nested dependencies are judged as acceptable as control sentences with only two nested dependencies, whereas sentences with three nested dependencies are judged as only marginally acceptable. This argues against De Vries et al.'s (2011 claim that the human parser can process no more than two nested dependencies. The results are used to refine the Verb-Cluster Complexity Hypothesis of Bader and Schmid (2009a. The second and the third experiment investigate sentences with four nested dependencies in more detail in order to explore alternative sources of sentence complexity: the number of predicted heads to be held in working memory (storage cost in terms of the Dependency Locality Theory [DLT], Gibson, 2000 and the length of the involved dependencies (integration cost in terms of the DLT. Experiment 2 investigates sentences for which storage cost and integration cost make conflicting predictions. The results show that storage cost outweighs integration cost. Experiment 3 shows that increasing integration cost in sentences

  4. Luminescent Hydrogel Particles Prepared by Self-Assembly of β-Cyclodextrin Polymer and Octahedral Molybdenum Cluster Complexes

    Czech Academy of Sciences Publication Activity Database

    Kirakci, Kaplan; Šícha, Václav; Holub, Josef; Kubát, Pavel; Lang, Kamil

    2014-01-01

    Roč. 53, č. 24 (2014), s. 13012-13018 ISSN 0020-1669 R&D Projects: GA ČR GA13-05114S Institutional support: RVO:61388980 ; RVO:61388955 Keywords : Octahedral Molybdenum Cluster * Hydrogel * Luminescence Subject RIV: CA - Inorganic Chemistry Impact factor: 4.762, year: 2014

  5. Determination of Carbonyl Compounds in Exhaled Cigarette Smoke

    Directory of Open Access Journals (Sweden)

    Moldoveanu S

    2014-12-01

    Full Text Available This paper presents the findings on a quantitative evaluation of carbonyl levels in exhaled cigarette smoke from human subjects. The cigarettes evaluated include products with 5.0 mg ‘tar’, 10.6 mg ‘tar’ and 16.2 mg ‘tar’, where ‘tar’ is defined as the weight of total wet particulate matter (TPM minus the weight of nicotine and water, and the cigarettes are smoked following U.S. Federal Trade Commission (FTC recommendations. The measured levels of carbonyls in the exhaled smoke were compared with calculated yields of carbonyls in the inhaled smoke and a retention efficiency was obtained. The number of human subjects included a total of ten smokers for the 10.6 mg ‘tar’, five for the 16.2 mg ‘tar’, and five for the 5.0 mg ‘tar’ product, each subject smoking three cigarettes. The analyzed carbonyl compounds included several aldehydes (formaldehyde, acetaldehyde, acrolein, propionaldehyde, crotonaldehyde and n-butyraldehyde, and two ketones (acetone and 2-butanone. The smoke collection from the human subjects was vacuum assisted. Exhaled smoke was collected on Cambridge pads pretreated with a solution of dinitrophenylhydrazine (DNPH followed by high performance liquid chromatography (HPLC analysis of the dinitrophenylhydrazones of the carbonyl compounds. The cigarette butts from the smokers were collected and analyzed for nicotine. The nicotine levels for the cigarette butts from the smokers were used to calculate the level of carbonyls in the inhaled smoke, based on calibration curves. These were generated separately by analyzing the carbonyls in smoke and the nicotine in the cigarette butts obtained by machine smoking under different puffing regimes. The comparison of the level of carbonyl compounds in exhaled smoke with that from the inhaled smoke showed high retention of all the carbonyls. The retention of aldehydes was above 95% for all three different ‘tar’ levels cigarettes. The ketones were retained with a

  6. Emissions of carbonyl compounds from various cookstoves in China

    International Nuclear Information System (INIS)

    Zhang, J.; Smith, K.R.; Univ. of California, Berkeley, CA

    1999-01-01

    This paper presents a new database of carbonyl emission factors for commonly used cookstoves in China. The emission factors, reported both on a fuel-mass basis (mg/kg) and on a defined cooking-task basis (mg/task), were determined using a carbon balance approach for 22 types of fuel/stove combinations. These include various stoves using different species of crop residues and wood, kerosene, and several types of coals and gases. The results show that all the tested cookstoves produced formaldehyde and acetaldehyde and that the vast majority of the biomass stoves produced additional carbonyl compounds such as acetone, acrolein, propionaldehyde, crotonaldehyde, 2-butanone, isobutyraldehyde, butyraldehyde, isovaleraldehyde, valeraldehyde, hexaldehyde, benzaldehyde, o-tolualdehyde, m,p-tolualdehyde, and 2,4-dimethylbenzaldehyde. Carbonyls other than formaldehyde and acetaldehyde, however, were rarely generated by burning coal, coal gas, and natural gas. Kerosene and LPG stoves generated more carbonyl compounds than coal, coal gas, and natural gas stoves, but less than biomass stoves. Indoor levels of carbonyl compounds for typical village houses during cooking hours, estimated using a mass balance model and the measured emission factors, can be high enough to cause acute health effects documented for formaldehyde exposure, depending upon house parameters and individuals' susceptibility

  7. Structural and Functional Characterization of an Archaeal Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-associated Complex for Antiviral Defense (CASCADE)

    DEFF Research Database (Denmark)

    Lintner, Nathanael G; Kerou, Melina; Brumfield, Susan K

    2011-01-01

    In response to viral infection, many prokaryotes incorporate fragments of virus-derived DNA into loci called clustered regularly interspaced short palindromic repeats (CRISPRs). The loci are then transcribed, and the processed CRISPR transcripts are used to target invading viral DNA and RNA....... The Escherichia coli "CRISPR-associated complex for antiviral defense" (CASCADE) is central in targeting invading DNA. Here we report the structural and functional characterization of an archaeal CASCADE (aCASCADE) from Sulfolobus solfataricus. Tagged Csa2 (Cas7) expressed in S. solfataricus co-purifies with Cas5......a-, Cas6-, Csa5-, and Cas6-processed CRISPR-RNA (crRNA). Csa2, the dominant protein in aCASCADE, forms a stable complex with Cas5a. Transmission electron microscopy reveals a helical complex of variable length, perhaps due to substoichiometric amounts of other CASCADE components. A recombinant Csa2...

  8. Tap and trill clusters in typical and protracted phonological development: Challenging segments in complex phonological environments. Introduction to the special issue.

    Science.gov (United States)

    Stemberger, Joseph Paul; Bernhardt, Barbara May

    2018-01-01

    The papers in this crosslinguistic issue address children's acquisition of word-initial rhotic clusters in languages with taps/trills, that is, the acquisition of challenging segments in complex environments. Several papers also include comparisons with singleton rhotics and/or /l/ as a singleton or in clusters. The studies are part of a larger investigation that uses similar methodologies across languages in order to enhance crosslinguistic comparability (Bernhardt and Stemberger, 2012, 2015). Participants for the current studies were monolingual preschoolers with typical or protracted phonological development who speak one of the following languages: Germanic (Icelandic/Swedish); Romance (Portuguese/Spanish); Slavic (Bulgarian/Slovenian) and Finno-Ugric (Hungarian). This introductory paper describes characteristics of taps/trills and general methodology across the studies, concluding with predicted patterns of acquisition. The seven papers that follow are in a sense the 'results' for this introduction. A concluding paper discusses major findings and their implications for theory, research and clinical practice.

  9. Bacillus cereus Fnr binds a [4Fe-4S] cluster and forms a ternary complex with ResD and PlcR

    Directory of Open Access Journals (Sweden)

    Esbelin Julia

    2012-06-01

    Full Text Available Abstract Background Bacillus cereus is a facultative anaerobe that causes diarrheal disease in humans. Diarrheal syndrome may result from the secretion of various virulence factors including hemolysin BL and nonhemolytic enterotoxin Nhe. Expression of genes encoding Hbl and Nhe is regulated by the two redox systems, ResDE and Fnr, and the virulence regulator PlcR. B. cereus Fnr is a member of the Crp/Fnr family of iron-sulfur (Fe-S proteins. Only its apo-form has so far been studied. A major goal in deciphering the Fnr-dependent regulation of enterotoxin genes is thus to obtain and characterize holoFnr. Results Fnr has been subjected to in vitro Fe-S cluster reconstitution under anoxic conditions. UV-visible and EPR spectroscopic analyses together with the chemical estimation of the iron content indicated that Fnr binds one [4Fe-4S]2+ cluster per monomer. Atmospheric O2 causes disassembly of the Fe-S cluster, which exhibited a half-life of 15 min in air. Holo- and apoFnr have similar affinities for the nhe and hbl promoter regions, while holoFnr has a higher affinity for fnr promoter region than apoFnr. Both the apo- and holo-form of Fnr interact with ResD and PlcR to form a ternary complex. Conclusions Overall, this work shows that incorporation of the [4Fe-4S]2+ cluster is not required for DNA binding of Fnr to promoter regions of hbl and nhe enterotoxin genes or for the formation of a ternary complex with ResD and PlcR. This points to some new unusual properties of Fnr that may have physiological relevance in the redox regulation of enterotoxin gene regulation.

  10. Copper-catalyzed 1,2-addition of α-carbonyl iodides to alkynes.

    Science.gov (United States)

    Xu, Tao; Hu, Xile

    2015-01-19

    β,γ-Unsaturated ketones are an important class of organic molecules. Herein, copper catalysis has been developed for the synthesis of β-γ-unsaturated ketones through 1,2-addition of α-carbonyl iodides to alkynes. The reactions exhibit wide substrate scope and high functional group tolerance. The reaction products are versatile synthetic intermediates to complex small molecules. The method was applied for the formal synthesis of (±)-trichostatin A, a histone deacetylase inhibitor. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Cationic polyhydrido cluster complexes. Crystal and molecular structures of (Ir3(Ph2P(CH2)3PPh2)3(H)7(CO))2+ and (Ir3(Ph2P(CH2)2(2-py))3(H)7)2+

    International Nuclear Information System (INIS)

    Hsienhau Wang; Casalnuovo, A.L.; Johnson, B.J.; Mueting, A.M.; Pignolet, L.H.

    1988-01-01

    Two new cationic polyhydrido cluster complexes of iridium have been synthesized and characterized by single-crystal x-ray diffraction and by ir and 1 H and 31 P NMR spectroscopy (Ir 3 (dppp) 3 (H) 7 (CO)) 2+ (2) and (Ir3 (PN) 3 (H) 7)2+ (5), where dppp = 1,3-bis(diphenylphosphino)propane and PN = 1-(2-pyridyl)-2-(diphenylphosphino)ethane, were synthesized by the reaction of CO with (Ir 3 (dppp) 3 (H) 7 ) 2+ (1) in CH 2 Cl 2 solution and H 2 with (Ir(PN)(COD)) + (4) in CH 3 OH solution, respectively. Crystal structures for both compounds is reported. The hydride positions were not located in the crystal structure analyses but were deduced from structural and 1 H NMR data. The molecular structure of 2 consists of a bilateral triangle of three iridium atoms with a carbonyl at the vertex and a chelating dppp ligand on each iridium atom. 1 H NMR data with use of acetone-d 6 as solvent showed that 2 possesses four doubly bridging hydrides and three terminal hydrides, yielding C 1 symmetry. The molecular structure of 5 consists of an approximately equilateral triangle of three iridium atoms (average Ir-Ir distance 2.746 (1) angstrom) with one PN ligand chelated to each iridium atom. 1 H NMR analysis, with use of CD 2 Cl 2 as solvent, showed that 5 has one triply bridging hydride and six terminal hydrides, giving C 3 symmetry. (Ir 3 (dppp) 3 (H) 7 (CH 3 C 6 H 4 NC)) 2+ (3) a complex structurally analogous to 2, was synthesized from 1 and p-tolyl isocyanide in CH 2 Cl 2 solution and characterized by ir and 1 H and 31 P NMR spectroscopy. 44 refs., 3 figs., 3 tabs

  12. Interaction between Nbp35 and Cfd1 proteins of cytosolic Fe-S cluster assembly reveals a stable complex formation in Entamoeba histolytica.

    Directory of Open Access Journals (Sweden)

    Shadab Anwar

    Full Text Available Iron-Sulfur (Fe-S proteins are involved in many biological functions such as electron transport, photosynthesis, regulation of gene expression and enzymatic activities. Biosynthesis and transfer of Fe-S clusters depend on Fe-S clusters assembly processes such as ISC, SUF, NIF, and CIA systems. Unlike other eukaryotes which possess ISC and CIA systems, amitochondriate Entamoeba histolytica has retained NIF & CIA systems for Fe-S cluster assembly in the cytosol. In the present study, we have elucidated interaction between two proteins of E. histolytica CIA system, Cytosolic Fe-S cluster deficient 1 (Cfd1 protein and Nucleotide binding protein 35 (Nbp35. In-silico analysis showed that structural regions ranging from amino acid residues (P33-K35, G131-V135 and I147-E151 of Nbp35 and (G5-V6, M34-D39 and G46-A52 of Cfd1 are involved in the formation of protein-protein complex. Furthermore, Molecular dynamic (MD simulations study suggested that hydrophobic forces surpass over hydrophilic forces between Nbp35 and Cfd1 and Van-der-Waal interaction plays crucial role in the formation of stable complex. Both proteins were separately cloned, expressed as recombinant fusion proteins in E. coli and purified to homogeneity by affinity column chromatography. Physical interaction between Nbp35 and Cfd1 proteins was confirmed in vitro by co-purification of recombinant Nbp35 with thrombin digested Cfd1 and in vivo by pull down assay and immunoprecipitation. The insilico, in vitro as well as in vivo results prove a stable interaction between these two proteins, supporting the possibility of its involvement in Fe-S cluster transfer to target apo-proteins through CIA machinery in E. histolytica. Our study indicates that initial synthesis of a Fe-S precursor in mitochondria is not necessary for the formation of Cfd1-Nbp35 complex. Thus, Cfd1 and Nbp35 with the help of cytosolic NifS and NifU proteins can participate in the maturation of non-mitosomal Fe-S proteins

  13. Catalytic production of metal carbonyls from metal oxides

    Science.gov (United States)

    Sapienza, Richard S.; Slegeir, William A.; Foran, Michael T.

    1984-01-01

    This invention relates to the formation of metal carbonyls from metal oxides and specially the formation of molybdenum carbonyl and iron carbonyl from their respective oxides. Copper is used here in admixed form or used in chemically combined form as copper molybdate. The copper/metal oxide combination or combined copper is utilized with a solvent, such as toluene and subjected to carbon monoxide pressure of 25 atmospheres or greater at about 150.degree.-260.degree. C. The reducing metal copper is employed in catalytic concentrations or combined concentrations as CuMoO.sub.4 and both hydrogen and water present serve as promoters. It has been found that the yields by this process have been salutary and that additionally the catalytic metal may be reused in the process to good effect.

  14. Synthesis and Structural Characterisation of [Ir4(CO8(CH3(m4-h3-Ph2PCCPh(m-PPh2] and of the Carbonylation Product [Ir4(CO8{C(OCH3}(m4-h3-Ph2PCCPh(m-PPh2]; First Evidence for the Formation of a CO Cluster Adduct before CO Insertion

    Directory of Open Access Journals (Sweden)

    Braga Dario

    1999-01-01

    Full Text Available Deprotonation of [(mu-HIr4(CO10(mu-PPh2], 1, gives [Ir4(CO10(mu-PPh2]- that reacts with Ph2PCCPh and CH3I to afford [Ir4(CO8(CH3(mu4-eta³-Ph2PCCPh(mu-PPh2], 2 (34%, besides [Ir4(CO9(mu3-eta³-Ph2PC(HCPh(mu-PPh2] and [(mu-HIr4(CO9(Ph2PCºCPh(mu-PPh2]. Compound 2 was characterised by a single crystal X-ray diffraction analysis and exhibits a flat butterfly of metal atoms, with the Ph2PCCPh ligand interacting with all four Ir atoms and the methyl group bonded terminally to a wingtip Ir atom. Carbonylation of 2 yields initially (25 °C, 20 min a CO addition product that, according to VT 31P{¹H} and 13C{¹H} studies, exists in solution in the form of two isomers 4A and 4B (8:1, and then (40 °C, 7 h, the CO insertion product [Ir4(CO8{C(OCH3}(mu4-eta³-Ph2PCCPh(mu-PPh2], 5. The molecular structure of 5, established by an X-ray analysis, is similar to that of 2, except for the acyl group that remains bound to the same Ir atom. The process is reversible at both stages. Treatment of 2 with PPh3 and P(OMe3 affords the CO substitution products [Ir4(CO7L(CH3(mu4-eta³-Ph2PCCPh(mu-PPh2] (L = PPh3, 6 and P(OMe3, 7, instead of the expected CO inserted products. According to the ¹H and 31P{¹H} NMR studies, the PPh3 derivative 6 exists in the form of two isomers (1:1 that differ with respect to the position of this ligand.

  15. Separation of Trace Amount Zn (II Using Additional Carbonyl and Carboxyl Groups Functionalized-Nano Graphene

    Directory of Open Access Journals (Sweden)

    A. Moghimi

    2013-01-01

    Full Text Available A novel and selective method for the fast determination of trace amounts of Zn(IIions in water samples has been developed.  The first additional carbonyl and carboxyl functionalized-nano graphene (SPFNano graphene. The presence of additional carbonyl and carboxyl groups located at the edge of the sheets makes GO sheets strongly hydrophilic, allowing them to readily swell and disperse in water. Based on these oxygen functionalities, different model structures of GO were used as absorbent for extraction of Zn (II   ions by solid phase extraction method. The complexes were eluted with HNO3 (2M10% V.V-1 methanol in acetone and determined the analyte by flame atomic absorption spectrometry.  The procedure is based on the selective formation of Zn (II at optimum pH by elution with organic eluents and determination by flame atomic absorption spectrometry. The method is based on complex formation on the surface of the ENVI-18 DISKTM disks modified carbonyl and carboxyl functionalized-nano graphene oxide molecules covalently bonded together followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effect of potential interfering ions, pH, SPFNano graphene, amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about 1000mL providing a preconcentration factor of 500. The maximum capacity of the disks was found to be 456± 3 µg for Zn2+.The limit of detection of the proposed method is 5ng per 1000mL.The method was applied to the extraction and recovery of Zn in different water samples.

  16. Cellular internalization and morphological analysis after intravenous injection of a highly hydrophilic octahedral rhenium cluster complex - a new promising X-ray contrast agent.

    Science.gov (United States)

    Krasilnikova, Anna A; Solovieva, Anastasiya O; Trifonova, Kristina E; Brylev, Konstantin A; Ivanov, Anton A; Kim, Sung-Jin; Shestopalov, Michael A; Fufaeva, Maria S; Shestopalov, Alexander M; Mironov, Yuri V; Poveshchenko, Alexander F; Shestopalova, Lidia V

    2016-11-01

    The octahedral cluster compound Na 2 H 8 [{Re 6 Se 8 }(P(C 2 H 4 CONH 2 )(C 2 H 4 COO) 2 ) 6 ] has been shown to be highly radio dense, thus becoming a promising X-ray contrast agent. It was also shown that this compound had low cytotoxic effect in vitro, low acute toxicity in vivo and was eliminated rapidly from the body through the urinary tract. The present contribution describes a more detailed cellular internalization assay and morphological analysis after intravenous injection of this hexarhenium cluster compound at different doses. The median lethal dose (LD 50 ) of intravenously administrated compound was calculated (4.67 ± 0.69 g/kg). Results of the study clearly indicated that the cluster complex H n [{Re 6 Se 8 }(P(C 2 H 4 CONH 2 )(C 2 H 4 COO) 2 ) 6 ] n-10 was not internalized into cells in vitro and induced only moderate morphological alterations of kidneys at high doses without any changes in morphology of liver, spleen, duodenum, or heart of mice. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  17. Complex time series analysis of PM10 and PM2.5 for a coastal site using artificial neural network modelling and k-means clustering

    Science.gov (United States)

    Elangasinghe, M. A.; Singhal, N.; Dirks, K. N.; Salmond, J. A.; Samarasinghe, S.

    2014-09-01

    This paper uses artificial neural networks (ANN), combined with k-means clustering, to understand the complex time series of PM10 and PM2.5 concentrations at a coastal location of New Zealand based on data from a single site. Out of available meteorological parameters from the network (wind speed, wind direction, solar radiation, temperature, relative humidity), key factors governing the pattern of the time series concentrations were identified through input sensitivity analysis performed on the trained neural network model. The transport pathways of particulate matter under these key meteorological parameters were further analysed through bivariate concentration polar plots and k-means clustering techniques. The analysis shows that the external sources such as marine aerosols and local sources such as traffic and biomass burning contribute equally to the particulate matter concentrations at the study site. These results are in agreement with the results of receptor modelling by the Auckland Council based on Positive Matrix Factorization (PMF). Our findings also show that contrasting concentration-wind speed relationships exist between marine aerosols and local traffic sources resulting in very noisy and seemingly large random PM10 concentrations. The inclusion of cluster rankings as an input parameter to the ANN model showed a statistically significant (p advanced air dispersion models.

  18. Lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria

    Directory of Open Access Journals (Sweden)

    Muscariello Lidia

    2006-05-01

    Full Text Available Abstract Background Genomes of gram-positive bacteria encode many putative cell-surface proteins, of which the majority has no known function. From the rapidly increasing number of available genome sequences it has become apparent that many cell-surface proteins are conserved, and frequently encoded in gene clusters or operons, suggesting common functions, and interactions of multiple components. Results A novel gene cluster encoding exclusively cell-surface proteins was identified, which is conserved in a subgroup of gram-positive bacteria. Each gene cluster generally has one copy of four new gene families called cscA, cscB, cscC and cscD. Clusters encoding these cell-surface proteins were found only in complete genomes of Lactobacillus plantarum, Lactobacillus sakei, Enterococcus faecalis, Listeria innocua, Listeria monocytogenes, Lactococcus lactis ssp lactis and Bacillus cereus and in incomplete genomes of L. lactis ssp cremoris, Lactobacillus casei, Enterococcus faecium, Pediococcus pentosaceus, Lactobacillius brevis, Oenococcus oeni, Leuconostoc mesenteroides, and Bacillus thuringiensis. These genes are neither present in the genomes of streptococci, staphylococci and clostridia, nor in the Lactobacillus acidophilus group, suggesting a niche-specific distribution, possibly relating to association with plants. All encoded proteins have a signal peptide for secretion by the Sec-dependent pathway, while some have cell-surface anchors, novel WxL domains, and putative domains for sugar binding and degradation. Transcriptome analysis in L. plantarum shows that the cscA-D genes are co-expressed, supporting their operon organization. Many gene clusters are significantly up-regulated in a glucose-grown, ccpA-mutant derivative of L. plantarum, suggesting catabolite control. This is supported by the presence of predicted CRE-sites upstream or inside the up-regulated cscA-D gene clusters. Conclusion We propose that the CscA, CscB, CscC and Csc

  19. Creation of a 3Mn/1Fe cluster in the oxygen-evolving complex of photosystem II and investigation of its functional activity.

    Science.gov (United States)

    Semin, B К; Davletshina, L N; Seibert, M; Rubin, A B

    2018-01-01

    Extraction of Mn cations from the oxygen-evolving complex (OEC) of Ca-depleted PSII membranes (PSII[-Ca,4Mn]) by reductants like hydroquinone (H 2 Q) occurs with lower efficiency at acidic pH (2Mn/reaction center [RC] are extracted at pH5.7) than at neutral pH (3Mn/RC are extracted at pH6.5) [Semin et al. Photosynth. Res. 125 (2015) 95]. Fe(II) also extracts Mn cations from PSII(-Ca,4Mn), but only 2Mn/RC at pH6.5, forming a heteronuclear 2Mn/2Fe cluster [Semin and Seibert, J. Bioenerg. Biomembr. 48 (2016) 227]. Here we investigated the efficiency of Mn extraction by Fe(II) at acidic pH and found that Fe(II) cations can extract only 1Mn/RC from PSII(-Ca,4Mn) membranes at pH 5.7, forming a 3Mn/1Fe cluster. Also we found that the presence of Fe cations in a heteronuclear cluster (2Mn/2Fe) increases the resistance of the remaining Mn cations to H 2 Q action, since H 2 Q can extract Mn cations from homonuclear Mn clusters of PSII(-Ca,4Mn) and PSII(-Ca,2Mn) membranes but not from the heteronuclear cluster in PSII(-Ca,2Mn,2Fe) membranes. H 2 Q also cannot extract Mn from PSII membranes obtained by incubation of PSII(-Ca,4Mn) membranes with Fe(II) cations at pH5.7, which suggests the formation of a heteronuclear 3Mn/1Fe cluster in the OEC. Functional activity of PSII with a 3Mn/1Fe cluster was investigated. PSII preparations with a 3Mn/1Fe cluster in the OEC are able to photoreduce the exogenous electron acceptor 2,6-dichlorophenolindophenol, possibly due to incomplete oxidation of water molecules as is the case with PSII(-Ca,2Mn,2Fe) samples. However, in the contrast to PSII(-Ca,2Mn,2Fe) samples PSII(-Ca,3Mn,1Fe) membranes can evolve O 2 at a low rate in the presence of exogenous Ca 2+ (at about 27% of the rate of O 2 evolution in native PSII membranes). The explanation for this phenomenon (either water splitting and production of molecular O 2 by the 3Mn/1Fe cluster or apparent O 2 evolution due to minor contamination of PSII(3Mn,1Fe) samples with PSII(-Ca,4Mn) membranes

  20. Ubiquitination-Linked Phosphorylation of the FANCI S/TQ Cluster Contributes to Activation of the Fanconi Anemia I/D2 Complex

    Directory of Open Access Journals (Sweden)

    Ronald S. Cheung

    2017-06-01

    Full Text Available Repair of interstrand crosslinks by the Fanconi anemia (FA pathway requires both monoubiquitination and de-ubiquitination of the FANCI/FANCD2 (FANCI/D2 complex. In the standing model, the phosphorylation of six sites in the FANCI S/TQ cluster domain occurs upstream of, and promotes, FANCI/D2 monoubiquitination. We generated phospho-specific antibodies against three different S/TQ cluster sites (serines 556, 559, and 565 on human FANCI and found that, in contrast to the standing model, distinct FANCI sites were phosphorylated either predominantly upstream (ubiquitination independent; serine 556 or downstream (ubiquitination-linked; serines 559 and 565 of FANCI/D2 monoubiquitination. Ubiquitination-linked FANCI phosphorylation inhibited FANCD2 de-ubiquitination and bypassed the need to de-ubiquitinate FANCD2 to achieve effective interstrand crosslink repair. USP1 depletion suppressed ubiquitination-linked FANCI phosphorylation despite increasing FANCI/D2 monoubiquitination, providing an explanation of why FANCD2 de-ubiquitination is important for function of the FA pathway. Our work results in a refined model of how FANCI phosphorylation activates the FANCI/D2 complex.

  1. A novel cluster of Mycobacterium abscessus complex revealed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS).

    Science.gov (United States)

    Suzuki, Hiromichi; Yoshida, Shiomi; Yoshida, Atsushi; Okuzumi, Katsuko; Fukusima, Atsuhito; Hishinuma, Akira

    2015-12-01

    Mycobacterium abscessus complex is a rapidly growing mycobacterium consisting of 3 subspecies, M. abscessus, Mycobacterium massiliense, and Mycobacterium bolletii. However, rapid and accurate species identification is difficult. We first evaluated a suitable protocol of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for distinguishing these subspecies. Then, we studied spectral signals by MALDI-TOF MS in 59 M. abscessus, 42 M. massiliense, and 2 M. bolletii. Among several specific spectral signals, 4 signals clearly differentiate M. massiliense from the other 2 subspecies, M. abscessus and M. bolletii. Moreover, 6 of the 42 M. massiliense isolates showed a spectral pattern similar to M. abscessus. These isolates correspond to the distinctive class of M. massiliense (cluster D) which is closer to M. abscessus by the previous variable number tandem repeat analysis. These results indicate that MALDI-TOF MS is not only useful for the identification of 3 subspecies of M. abscessus complex but also capable of distinguishing clusters of M. massiliense. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Metal-Diazo Radicals of α-Carbonyl Diazomethanes

    Science.gov (United States)

    Li, Feifei; Xiao, Longqiang; Liu, Lijian

    2016-03-01

    Metal-diazo radicals of α-carbonyl diazomethanes are new members of the radical family and are precursors to metal-carbene radicals. Herein, using electron paramagnetic resonance spectroscopy with spin-trapping, we detect diazo radicals of α-carbonyl diazomethanes, induced by [RhICl(cod)]2, [CoII(por)] and PdCl2, at room temperature. The unique quintet signal of the Rh-diazo radical was observed in measurements of α-carbonyl diazomethane adducts of [RhICl(cod)]2 in the presence of 5,5-dimethyl-pyrroline-1-N-oxide (DMPO). DFT calculations indicated that 97.2% of spin density is localized on the diazo moiety. Co- and Pd-diazo radicals are EPR silent but were captured by DMPO to form spin adducts of DMPO-N• (triplet-of-sextets signal). The spin-trapping also provides a powerful tool for detection of metal-carbene radicals, as evidenced by the DMPO-trapped carbene radicals (DMPO-C•, sextet signal) and 2-methyl-2-nitrosopropane-carbene adducts (MNP-C•, doublet-of-triplets signal). The transformation of α-carbonyl diazomethanes to metal-carbene radicals was confirmed to be a two-step process via metal-diazo radicals.

  3. Carbonyl atmospheric reaction products of aromatic hydrocarbons in ambient air

    Science.gov (United States)

    Obermeyer, Genevieve; Aschmann, Sara M.; Atkinson, Roger; Arey, Janet

    To convert gaseous carbonyls to oximes during sampling, an XAD-4 resin denuder system pre-coated with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine and followed by analysis with methane positive chemical ionization gas chromatography/mass spectrometry was used to measure carbonyls in ambient air samples in Riverside, CA. In conjunction with similar analyses of environmental chamber OH radical-initiated reactions of o- and p-xylene, 1,2,4-trimethylbenzene, ethylbenzene, 4-hydroxy-2-butanone and 1,4-butanediol, we identified benzaldehyde, o-, m- and p-tolualdehyde and acetophenone and the dicarbonyls glyoxal, methylglyoxal, biacetyl, ethylglyoxal, 1,4-butenedial, 3-hexene-2,5-dione, 3-oxo-butanal, 1,4-butanedial and malonaldehyde in the ambient air samples. As discussed, these carbonyls and dicarbonyls can be formed from the OH radical-initiated reactions of aromatic hydrocarbons and other volatile organic compounds emitted into the atmosphere, and we conclude that in situ atmospheric formation is a major source of these carbonyls in our Riverside, CA, ambient air samples.

  4. Plasma protein carbonyl levels and breast cancer risk

    Czech Academy of Sciences Publication Activity Database

    Rössner ml., Pavel; Terry, M. B.; Gammon, M. D.; Agrawal, M.; Zhang, F. F.; Ferris, J.S.; Teitelbaum, S. L.; Eng, S. M.; Gaudet, M. M.; Neugut, A. I.; Santella, R. M.

    2007-01-01

    Roč. 11, č. 5 (2007), s. 1138-1148 ISSN 1582-1838 Institutional research plan: CEZ:AV0Z50390512 Keywords : oxidative stress * protein carbonyl * breast cancer Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 6.807, year: 2007

  5. cyclo-addition reaction of triplet carbonyl compounds to substituted ...

    Indian Academy of Sciences (India)

    Unknown

    cited state energy of the olefin must be higher than that of the ketone so that ... the first singlet and triplet1,3 (n, π*) excited state of the carbonyl compounds.3,4 ... of the oxetane via carbon–carbon and carbon–oxygen attacks. They found the ...

  6. Olefination of carbonyl compounds: modern and classical methods

    Energy Technology Data Exchange (ETDEWEB)

    Korotchenko, V N; Nenajdenko, Valentine G; Balenkova, Elizabeth S [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Shastin, Aleksey V [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2004-10-31

    The published data on the methods for alkene synthesis by olefination of carbonyl compounds are generalised and systematised. The main attention is given to the use of transition metals and organoelement compounds. The review covers the data on both classical and newly developed methods that are little known to chemists at large.

  7. Olefination of carbonyl compounds: modern and classical methods

    Science.gov (United States)

    Korotchenko, V. N.; Nenajdenko, Valentine G.; Balenkova, Elizabeth S.; Shastin, Aleksey V.

    2004-10-01

    The published data on the methods for alkene synthesis by olefination of carbonyl compounds are generalised and systematised. The main attention is given to the use of transition metals and organoelement compounds. The review covers the data on both classical and newly developed methods that are little known to chemists at large.

  8. Frustrated Lewis pairs-assisted reduction of carbonyl compounds

    DEFF Research Database (Denmark)

    Marek, Ales; Pedersen, Martin Holst Friborg

    2015-01-01

    An alternative and robust method for the reduction of carbonyl groups by frustrated Lewis pairs (FLPs) is reported in this paper. With its very mild reaction conditions, good to excellent yields, absolute regioselectivity and the non-metallic character of the reagent, it provides an excellent too...

  9. Organometallic and Bioorganometallic Chemistry - Ferrocene and Metal Carbonyls

    Directory of Open Access Journals (Sweden)

    Čakić Semenčić, M.

    2011-02-01

    procedure to use metal atoms in organometallics as labelling agents for antigens (A in immunoassays (IA is called metalloimmunoassay (MIA, Cais, 1977. Carbonyl metalloimmunoassay (CMIA is a heterogeneous competitive-type MIA using M-CO complexes as tracers, and FT-IR spectroscopy for quantification. This procedure allowed the simultaneous multiple IA reaching the fentomole concentration (Jaouen, 2000. From the variety of bioorganometallics synthesis and properties of the simple ferrocene-amino acids/peptides conjugates and ferrocene labelled carbohydrates, as well as the structure and function determination of B12 vitamin are described in this review.

  10. Degradation of carbonyl hydroperoxides in the atmosphere and in combustion

    KAUST Repository

    Xing, Lili

    2017-10-12

    Oxygenates with carbonyl and hydroperoxy functional groups are important intermediates that are generated during the autooxidation of organic compounds in the atmosphere and during the autoignition of transport fuels. In the troposphere, the degradation of carbonyl hydroperoxides leads to low-vapor-pressure polyfunctional species that be taken into in cloud and fog droplets or to the formation of secondary organic aerosols (SOAs). In combustion, the fate of carbonyl hydroperoxides is important for the performance of advanced combustion engines, especially for autoignition. A key fate of the carbonyl hydroperoxides is reac-tion with OH radicals, for which kinetics data are experimentally unavailable. Here, we study 4-hydroperoxy-2-pentanone (CH3C(=O)CH2CH(OOH)CH3) as a model compound to clarify the kinetics of OH reactions with carbonyl hydroperoxides, in par-ticular H-atom abstraction and OH addition reactions. With a combination of electronic structure calculations, we determine previ-ously missing thermochemical data, and with multipath variational transition state theory (MP-VTST), a multidimensional tunnel-ing (MT) approximation, multiple-structure anharmonicity, and torsional potential anharmonicity we obtained much more accurate rate constants than the ones that can computed by conventional single-structure harmonic transition state theory (TST) and than the empirically estimated rate constants that are currently used in atmospheric and combustion modeling. The roles of various factors in determining the rates are elucidated. The pressure-dependent rate constants for the addition reaction are computed using system-specific quantum RRK theory. The calculated temperature range is 298-2400 K, and the pressure range is 0.01–100 atm. The accu-rate thermodynamic and kinetics data determined in this work are indispensable in the global modeling of SOAs in atmospheric science and in the detailed understanding and prediction of ignition properties of hydrocarbons

  11. Low pressure carbonylation of benzyl chloride = Die carbonylierung von benzylchlorid bei niedrigen drücken

    NARCIS (Netherlands)

    Luggenhorst, H.J.; Westerterp, K.R.

    1986-01-01

    For carbonylations, metal carbonyls, particularly cobalt and iron carbonyls, are often used as catalysts. These reactions take place under rather drastic reaction conditions, e.g. 200–300 °C and 60–100 MPa. In some patents it is stated that similar reactions using the same catalysts can also be

  12. Structural and functional characterization of an archaeal clustered regularly interspaced short palindromic repeat (CRISPR)-associated complex for antiviral defense (CASCADE).

    Science.gov (United States)

    Lintner, Nathanael G; Kerou, Melina; Brumfield, Susan K; Graham, Shirley; Liu, Huanting; Naismith, James H; Sdano, Matthew; Peng, Nan; She, Qunxin; Copié, Valérie; Young, Mark J; White, Malcolm F; Lawrence, C Martin

    2011-06-17

    In response to viral infection, many prokaryotes incorporate fragments of virus-derived DNA into loci called clustered regularly interspaced short palindromic repeats (CRISPRs). The loci are then transcribed, and the processed CRISPR transcripts are used to target invading viral DNA and RNA. The Escherichia coli "CRISPR-associated complex for antiviral defense" (CASCADE) is central in targeting invading DNA. Here we report the structural and functional characterization of an archaeal CASCADE (aCASCADE) from Sulfolobus solfataricus. Tagged Csa2 (Cas7) expressed in S. solfataricus co-purifies with Cas5a-, Cas6-, Csa5-, and Cas6-processed CRISPR-RNA (crRNA). Csa2, the dominant protein in aCASCADE, forms a stable complex with Cas5a. Transmission electron microscopy reveals a helical complex of variable length, perhaps due to substoichiometric amounts of other CASCADE components. A recombinant Csa2-Cas5a complex is sufficient to bind crRNA and complementary ssDNA. The structure of Csa2 reveals a crescent-shaped structure unexpectedly composed of a modified RNA-recognition motif and two additional domains present as insertions in the RNA-recognition motif. Conserved residues indicate potential crRNA- and target DNA-binding sites, and the H160A variant shows significantly reduced affinity for crRNA. We propose a general subunit architecture for CASCADE in other bacteria and Archaea.

  13. Quantum mechanical design and structures of hexanuclear sandwich complex and its multidecker sandwich clusters (Li6)n([18]annulene)n+1 (n = 1-3).

    Science.gov (United States)

    Wang, Shu-Jian; Li, Ying; Wu, Di; Wang, Yin-Feng; Li, Zhi-Ru

    2012-09-13

    By means of density functional theory, a hexanuclear sandwich complex [18]annulene-Li6-[18]annulene which consists of a central Li6 hexagon ring and large face-capping ligands, [18]annulene, is designed and investigated. The large interaction energy and HOMO-LUMO gap suggest that this novel charge-separated complex is highly stable and may be experimentally synthesized. In addition, the stability found in the [18]annulene-Li6-[18]annulene complex extends to multidecker sandwich clusters (Li6)n([18]annulene)n+1 (n = 2-3). The energy gain upon addition of a [18]annulene-Li6 unit to (Li6)n-1([18]annulene)n is pretty large (96.97-98.22 kcal/mol), indicating that even larger multideckers will also be very stable. Similar to ferrocene, such a hexanuclear sandwich complex could be considered as a versatile building block to find potential applications in different areas of chemistry, such as nanoscience and material science.

  14. Hydrothermal synthesis of carbonyl iron-carbon nanocomposite: Characterization and electromagnetic performance

    Directory of Open Access Journals (Sweden)

    Hakimeh Pourabdollahi

    Full Text Available In this research, the electromagnetic absorption properties of the carbonyl iron-carbon (CI/C nanocomposite prepared via hydrothermal reaction using glucose as carbon precursor was studied in the range of 8.2–12.4 GHz. In hydrothermal reaction, glucose solution containing CI particles, placed in autoclave for 4 h under 453 K. Using surface coating technology is a method that prevents Cl oxidation and improves CI electromagnetic absorption. The structure, morphology and magnetic performances of the prepared nanocomposites were characterized by X-ray diffraction (XRD, energy dispersive spectrometry (EDS, transmission electron microscopy (TEM and vibrating sample magnetometer (VSM. The electromagnetic properties including complex permittivity (εr, the permeability (µr, dielectric loss, magnetic loss, reflection loss, and attenuation constant were investigated using a vector network analyzer. For The CI/C nanocomposite, the bandwidth of −10 dB and −20 dB were obtained in the frequency range of 9.8–12.4 and 11.0–11.8 GHz, respectively. As well as, the reflection loss was −46.69 dB at the matching frequency of 11.5 GHz, when the matching thickness was 1.3 mm. While for CI particles the reflection loss for 4.4 mm thickness was −16.86 dB at the matching frequency of 12.3 GHz. The results indicate that the existence layer of carbon on carbonyl iron enhance the electromagnetic absorbing properties. Therefore, this nanocomposite can be suitable for in the radar absorbing coatings. Keywords: Hydrothermal synthesis, Carbonyl iron-carbon nanocomposite, Microwave absorption, Reflection loss

  15. Accumulation of carbonyls accelerates the formation of pentosidine, an advanced glycation end product: carbonyl stress in uremia.

    Science.gov (United States)

    Miyata, T; Ueda, Y; Yamada, Y; Izuhara, Y; Wada, T; Jadoul, M; Saito, A; Kurokawa, K; van Ypersele de Strihou, C

    1998-12-01

    Advanced glycation end product (AGE) formation is related to hyperglycemia in diabetes but not in uremia, because plasma AGE levels do not differ between diabetic and nondiabetic hemodialysis patients. The mechanism of this phenomenon remains elusive. Previously, it was suggested that elevation of AGE levels in uremia might result from the accumulation of unknown AGE precursors. The present study evaluates the in vitro generation of pentosidine, a well identified AGE structure. Plasma samples from healthy subjects and nondiabetic hemodialysis patients were incubated under air for several weeks. Pentosidine levels were determined at intervals by HPLC assay. Pentosidine rose to a much larger extent in uremic than in control plasma. Pentosidine yield, i.e., the change in pentosidine level between 0 and 4 wk divided by 28 d, averaged 0.172 nmol/ml per d in uremic versus 0.072 nmol/ml per d in control plasma (P aminoguanidine and OPB-9195, which inhibit the Maillard reaction, lowered pentosidine yield in both uremic and control plasma. When ultrafiltrated plasma was exposed to 2,4-dinitrophenylhydrazine, the yield of hydrazones, formed by interaction with carbonyl groups, was markedly higher in uremic than in control plasma. These observations strongly suggest that the pentosidine precursors accumulated in uremic plasma are carbonyl compounds. These precursors are unrelated to glucose or ascorbic acid, whose concentration is either normal or lowered in uremic plasma. They are also unrelated to 3-deoxyglucosone, a glucose-derived dicarbonyl compound whose level is raised in uremic plasma: Its addition to normal plasma fails to increase pentosidine yield. This study reports an elevated level of reactive carbonyl compounds ("carbonyl stress") in uremic plasma. Most have a lower than 5000 Da molecular weight and are thus partly removed by hemodialysis. Their effect on pentosidine generation can be inhibited by aminoguanidine or OPB-9195. Carbonyl stress might contribute to

  16. Rotational spectrum and structure of the carbonyl sulfide-trifluoromethane weakly bound dimer.

    Science.gov (United States)

    Serafin, Michal M; Peebles, Sean A

    2006-11-02

    Pure rotational spectra of five isotopomers of the 1:1 weakly bound complex formed between carbonyl sulfide and trifluoromethane (TFM) have been measured using Fourier transform microwave spectroscopy. The experimental rotational constants and dipole moment components are consistent with a structure of C(s) symmetry in which the dipole moment vectors of OCS and HCF(3) are aligned antiparallel and at an angle of about 40 degrees and with a center of mass separation of 3.965(26) A. The derived H...O distance is 2.90(5) A, which is up to 0.6 A longer than is seen in other similar TFM complexes exhibiting C-H...O interactions. Ab initio calculations at the MP2/6-311++G(2d,2p) level give a structure with rotational constants that are in reasonable agreement with those of the normal isotopic species.

  17. ⁹⁹mTc pyrene derivative complex causes double-strand breaks in dsDNA mainly through cluster-mediated indirect effect in aqueous solution.

    Directory of Open Access Journals (Sweden)

    Wei-Ju Chung

    Full Text Available Radiation therapy for cancer patients works by ionizing damage to nuclear DNA, primarily by creating double-strand breaks (DSB. A major shortcoming of traditional radiation therapy is the set of side effect associated with its long-range interaction with nearby tissues. Low-energy Auger electrons have the advantage of an extremely short effective range, minimizing damage to healthy tissue. Consequently, the isotope ⁹⁹mTc, an Auger electron source, is currently being studied for its beneficial potential in cancer treatment. We examined the dose effect of a pyrene derivative ⁹⁹mTc complex on plasmid DNA by using gel electrophoresis in both aqueous and methanol solutions. In aqueous solutions, the average yield per decay for double-strand breaks is 0.011±0.005 at low dose range, decreasing to 0.0005±0.0003 in the presence of 1 M dimethyl sulfoxide (DMSO. The apparent yield per decay for single-strand breaks (SSB is 0.04±0.02, decreasing to approximately a fifth with 1 M DMSO. In methanol, the average yield per decay of DSB is 0.54±0.06 and drops to undetectable levels in 2 M DMSO. The SSB yield per decay is 7.2±0.2, changing to 0.4±0.2 in the presence of 2 M DMSO. The 95% decrease in the yield of DSB in DMSO indicates that the main mechanism for DSB formation is through indirect effect, possibly by cooperative binding or clustering of intercalators. In the presence of non-radioactive ligands at a near saturation concentration, where radioactive Tc compounds do not form large clusters, the yield of SSB stays the same while the yield of DSB decreases to the value in DMSO. DSBs generated by ⁹⁹mTc conjugated to intercalators are primarily caused by indirect effects through clustering.

  18. ⁹⁹mTc pyrene derivative complex causes double-strand breaks in dsDNA mainly through cluster-mediated indirect effect in aqueous solution.

    Science.gov (United States)

    Chung, Wei-Ju; Cui, Yujia; Huang, Feng-Yun J; Tu, Tzu-Hui; Yang, Tzu-Sen; Lo, Jem-Mau; Chiang, Chi-Shiun; Hsu, Ian C

    2014-01-01

    Radiation therapy for cancer patients works by ionizing damage to nuclear DNA, primarily by creating double-strand breaks (DSB). A major shortcoming of traditional radiation therapy is the set of side effect associated with its long-range interaction with nearby tissues. Low-energy Auger electrons have the advantage of an extremely short effective range, minimizing damage to healthy tissue. Consequently, the isotope ⁹⁹mTc, an Auger electron source, is currently being studied for its beneficial potential in cancer treatment. We examined the dose effect of a pyrene derivative ⁹⁹mTc complex on plasmid DNA by using gel electrophoresis in both aqueous and methanol solutions. In aqueous solutions, the average yield per decay for double-strand breaks is 0.011±0.005 at low dose range, decreasing to 0.0005±0.0003 in the presence of 1 M dimethyl sulfoxide (DMSO). The apparent yield per decay for single-strand breaks (SSB) is 0.04±0.02, decreasing to approximately a fifth with 1 M DMSO. In methanol, the average yield per decay of DSB is 0.54±0.06 and drops to undetectable levels in 2 M DMSO. The SSB yield per decay is 7.2±0.2, changing to 0.4±0.2 in the presence of 2 M DMSO. The 95% decrease in the yield of DSB in DMSO indicates that the main mechanism for DSB formation is through indirect effect, possibly by cooperative binding or clustering of intercalators. In the presence of non-radioactive ligands at a near saturation concentration, where radioactive Tc compounds do not form large clusters, the yield of SSB stays the same while the yield of DSB decreases to the value in DMSO. DSBs generated by ⁹⁹mTc conjugated to intercalators are primarily caused by indirect effects through clustering.

  19. Paramagnetic transition-metal carbonyls and cyanides

    International Nuclear Information System (INIS)

    Symons, M.C.R.; Bratt, S.W.; Wyatt, J.L.

    1982-01-01

    Exposure of tetra-alkylammonium salts of [Cr(CO) 5 I] - , [Mo(CO) 5 I] - , and [W(CO) 5 I] - , and dilute solutions of [Re(CO) 5 Br] and [Re(CO) 5 I] in methyltetrahydrofuran (mthf), to 60 Co γ-rays at 77 K gave electron-addition products characterized by large hyperfine coupling to the halogen and metal nuclei. Orbital populations for the extra electrons estimated therefrom showed trends characteristic of antibonding electrons, and in all cases the extra electron appears to be accommodated in the metal-halogen σ* orbital comprising primarily (dsub(Z 2 )-psub(z)). For the tungsten complex, a species exhibiting additional hyperfine coupling to a single proton was also detected. A species previously assigned the formula [Cr(CO) 5 I] was prepared, but gave no detectable e.s.r. spectrum. (author)

  20. A phosphorescent silver(I)-gold (I) cluster complex that specifically lights up the nucleolus of living cells with FLIM imaging.

    Science.gov (United States)

    Chen, Min; Lei, Zhen; Feng, Wei; Li, Chunyan; Wang, Quan-Ming; Li, Fuyou

    2013-06-01

    The phosphorescent silver(I)-gold(I) cluster complex [CAu6Ag2(dppy)6](BF4)4 (N1) selectively stains the nucleolus, with a much lower uptake in the nucleus and cytoplasm, and exhibits excellent photostability. This Ag-Au cluster, which has a photoluminescent lifetime of microseconds, is particularly attractive as a probe in applications of time-gated microscopy. Investigation of the pathway of cellular entry indicated that N1 permeates the outer membrane and nuclear membrane of living cells through an energy-dependent and non-endocytic route within 10 min. High concentrations of N1 in the nucleolus have been quantified by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and transmission electron microscopy coupled with an energy dispersive X-ray analysis (TEM-EDXA), which also helped to elucidate the mechanism of the specific staining. Intracellular selective staining may be correlated with the microenvironment of the nucleolus, which is consistent with experiments conducted at different phases of the cell cycle. These results prove that N1 is a very attractive phosphorescent staining reagent for visualizing the nucleolus of living cells. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Phenolic carbonyls undergo rapid aqueous photodegradation to form low-volatility, light-absorbing products

    Science.gov (United States)

    Smith, Jeremy D.; Kinney, Haley; Anastasio, Cort

    2016-02-01

    We investigated the aqueous photochemistry of six phenolic carbonyls - vanillin, acetovanillone, guaiacyl acetone, syringaldehyde, acetosyringone, and coniferyl aldehyde - that are emitted from wood combustion. The phenolic carbonyls absorb significant amounts of solar radiation and decay rapidly via direct photodegradation, with lifetimes (τ) of 13-140 min under Davis, CA winter solstice sunlight at midday (solar zenith angle = 62°). The one exception is guaiacyl acetone, where the carbonyl group is not directly connected to the aromatic ring: This species absorbs very little sunlight and undergoes direct photodegradation very slowly (τ > 103 min). We also found that the triplet excited states (3C*) of the phenolic carbonyls rapidly oxidize syringol (a methoxyphenol without a carbonyl group), on timescales of 1-5 h for solutions containing 5 μM phenolic carbonyl. The direct photodegradation of the phenolic carbonyls, and the oxidation of syringol by 3C*, both efficiently produce low volatility products, with SOA mass yields ranging from 80 to 140%. Contrary to most aliphatic carbonyls, under typical fog conditions we find that the primary sink for the aromatic phenolic carbonyls is direct photodegradation in the aqueous phase. In areas of significant wood combustion, phenolic carbonyls appear to be small but significant sources of aqueous SOA: over the course of a few hours, nearly all of the phenolic carbonyls will be converted to SOA via direct photodegradation, enhancing the POA mass from wood combustion by approximately 3-5%.

  2. Structural insights into the neuroprotective-acting carbonyl reductase Sniffer of Drosophila melanogaster.

    Science.gov (United States)

    Sgraja, Tanja; Ulschmid, Julia; Becker, Katja; Schneuwly, Stephan; Klebe, Gerhard; Reuter, Klaus; Heine, Andreas

    2004-10-01

    In vivo studies with the fruit-fly Drosophila melanogaster have shown that the Sniffer protein prevents age-dependent and oxidative stress-induced neurodegenerative processes. Sniffer is a NADPH-dependent carbonyl reductase belonging to the enzyme family of short-chain dehydrogenases/reductases (SDRs). The crystal structure of the homodimeric Sniffer protein from Drosophila melanogaster in complex with NADP+ has been determined by multiple-wavelength anomalous dispersion and refined to a resolution of 1.75 A. The observed fold represents a typical dinucleotide-binding domain as detected for other SDRs. With respect to the cofactor-binding site and the region referred to as substrate-binding loop, the Sniffer protein shows a striking similarity to the porcine carbonyl reductase (PTCR). This loop, in both Sniffer and PTCR, is substantially shortened compared to other SDRs. In most enzymes of the SDR family this loop adopts a well-defined conformation only after substrate binding and remains disordered in the absence of any bound ligands or even if only the dinucleotide cofactor is bound. In the structure of the Sniffer protein, however, the conformation of this loop is well defined, although no substrate is present. Molecular modeling studies provide an idea of how binding of substrate molecules to Sniffer could possibly occur.

  3. The effect of complex workplace dietary interventions on employees' dietary intakes, nutrition knowledge and health status: a cluster controlled trial.

    Science.gov (United States)

    Geaney, Fiona; Kelly, Clare; Di Marrazzo, Jessica Scotto; Harrington, Janas M; Fitzgerald, Anthony P; Greiner, Birgit A; Perry, Ivan J

    2016-08-01

    Evidence on effective workplace dietary interventions is limited. The comparative effectiveness of a workplace environmental dietary modification and an educational intervention both alone and in combination was assessed versus a control workplace on employees' dietary intakes, nutrition knowledge and health status. In the Food Choice at Work cluster controlled trial, four large, purposively selected manufacturing workplaces in Ireland were allocated to control (N=111), nutrition education (Education) (N=226), environmental dietary modification (Environment) (N=113) and nutrition education and environmental dietary modification (Combined) (N=400) in 2013. Nutrition education included group presentations, individual consultations and detailed nutrition information. Environmental dietary modification included menu modification, fruit price discounts, strategic positioning of healthier alternatives and portion size control. Data on dietary intakes, nutrition knowledge and health status were obtained at baseline and follow-up at 7-9months. Multivariate analysis of covariance compared changes across the four groups with adjustment for age, gender, educational status and other baseline characteristics. Follow-up data at 7-9months were obtained for 541 employees (64% of 850 recruited) aged 18-64years: control: 70 (63%), Education: 113 (50%), 74 (65%) and Combined: 284 (71%). There were significant positive changes in intakes of saturated fat (p=0.013), salt (p=0.010) and nutrition knowledge (p=0.034) between baseline and follow-up in the combined intervention versus the control. Small but significant changes in BMI (-1.2kg/m(2) (95% CI -2.385, -0.018, p=0.047) were observed in the combined intervention. Effects in the education and environment alone workplaces were smaller and generally non-significant. Combining nutrition education and environmental dietary modification may be an effective approach for promoting a healthy diet and weight loss at work. Copyright © 2016

  4. Effects of a complex intervention on fall risk in the general practitioner setting: a cluster randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Freiberger E

    2013-08-01

    Full Text Available Ellen Freiberger,1 Wolfgang A Blank,2 Johannes Salb,1 Barbara Geilhof,3 Christian Hentschke,1 Peter Landendoerfer,2 Martin Halle,3 Monika Siegrist31Institute of Sport Science and Sport Universität Erlangen-Nürnberg, Nuremberg, Germany; 2Institute of General Practice, Technische Universität München, Munich, Germany; 3Department of Prevention, Rehabilitation and Sports Medicine, Technische Universität München, Munich, GermanyPurpose: To study the feasibility of first, reaching functionally declined, but still independent older persons at risk of falls through their general practitioner (GP and second, to reduce their physiological and psychological fall risk factors with a complex exercise intervention. We investigated the effects of a 16-week exercise intervention on physiological (function, strength, and balance and psychological (fear of falling outcomes in community-dwelling older persons in comparison with usual care. In addition, we obtained data on adherence of the participants to the exercise program.Methods: Tests on physical and psychological fall risk were conducted at study inclusion, and after the 16-week intervention period in the GP office setting. The 16-week intervention included progressive and challenging balance, gait, and strength exercise as well as changes to behavioral aspects. To account for the hierarchical structure in the chosen study design, with patients nested in GPs and measurements nested in patients, a three-level linear mixed effects model was determined for analysis.Results: In total, 33 GPs recruited 378 participants (75.4% females. The mean age of the participants was 78.1 years (standard deviation 5.9 years. Patients in the intervention group showed an improvement in the Timed-Up-and-Go-test (TUG that was 1.5 seconds greater than that showed by the control group, equivalent to a small to moderate effect. For balance, a relative improvement of 0.8 seconds was accomplished, and anxiety about falls was

  5. Measurements of carbonyls in a 13-story building.

    Science.gov (United States)

    Báez, Armando P; Padilla, Hugo G; García, Rocío M; Belmont, Raúl D; Torres, Maria del Carmen B

    2004-01-01

    Formaldehyde and acetaldehyde are emitted by many mobile and stationary sources and secondary aldehydes are intermediates in the photo-oxidation of organic compounds in the atmosphere. These aldehydes are emitted indoors by many materials such as furniture, carpets, heating and cooling systems, an by smoking. Carbonyls, mainly formaldehyde and acetaldehyde, have been studied because of their adverse health effects. In addition, formaldehyde is a suspected carcinogen. Therefore, the concentrations of formaldehyde and acetaldehyde were determined to assess the inhalation exposure doses to carbonyls for people who work in a 13-story building and in order to evaluate the cancer hazard. Carbonyl compounds in indoor and outdoor air were measured at a 13-story building located in Mexico City. The mezzanine, fifth and tenth floors, and the third level-parking garage were selected for sampling. Samples were collected in two sampling periods, the first from April 20 to 29, 1998 and the second from December 1 to 20, 1998. Carbonyls were sampled by means of DNHP-coated cartridges at a flow rate of 1 l min(-1) from 9:00 to 19:00 hours, during 2-hour time intervals and analyzed by HPLC with hours, during 2-hour time intervals and analyzed by HPLC with UV/VIS detection. Mean carbonyl concentrations were highest in the 3rd level-parking garage, with the formaldehyde concentration being the highest ranging from 108 to 418 microg m(-3). In working areas, the highest carbonyl arithmetic mean concentrations (AM) were observed on the 5th floor. Acetone and formaldehyde concentrations were highest in April ranging from 161 to 348 microg m(-3) (AM = 226) and from 157 to 270 microg m(-3) (AM = 221), respectively. Propionaldehyde and butyraldehyde were present in smaller concentrations ranging from 2 to 25 and 1 to 28 microg m(-3), respectively, considering all the samples. Mean indoor/outdoor ratios of carbonyls ranged from 1.8 to 9.6. A reduction of inhalation exposure doses of 41% and

  6. Reactions of α-phosphorylated carbonyl compounds with amino alcohols

    International Nuclear Information System (INIS)

    Moskva, V.V.; Sitdikova, T.Sh.; Zykova, T.V.; Alparova, M.V.; Shagvaleev, F.Sh.

    1986-01-01

    2-Aminoethanol reacts with carbonyl compounds with the formation, depending on the structure of the latter, either of a mixture of azomethines and oxazolidines, or of only azomethines. In the development of investigations on the reactivity of α-phosphorylated carbonyl compounds the authors studied the reactions of a number of amino alcohols with phosphorylated acetaldehyde and acetone. In both cases they observed the formation of compounds of enamine structure, oxazolidines and azomethines were not observed. By means of NMR spectroscopy they established clearly the formation of the E-isomeric products. The 1 H, 31 P, and 13 C NMR spectra were recorded on a WP-80 spectrometer. Chemical shifts of protons and 13 C nuclei are given relative to TMS, and phosphorus nuclei relative to orthophosphoric acid

  7. Synthetic and mechanistic aspects of titanium-mediated carbonyl olefinations

    Energy Technology Data Exchange (ETDEWEB)

    Petasis, N.A.; Staszewski, J.P.; Hu, Yong-Han; Lu, Shao-Po [Univ. of Southern California, Los Angeles, CA (United States)

    1995-12-31

    A new method for the olefination of carbonyl compounds with dimethyl titanocene, and other related bishydrocarbyl titanocene derivatives has been recently developed in the author`s laboratories. This process is experimentally convenient and works with various types of carbonyl compounds, including aldehydes, ketones, esters, lactones, carbonates, anhydrides, amides, imides, lactams, thioesters, selenoesters, and acylsilanes. More recent studies have focused on the scope and utility of this reaction, including mechanistic studies and synthetic applications. In addition to varying the reaction conditions, the authors have examined several mixed titanocene derivatives and have found ways for carrying out this type of olefination at room temperature, such as the use of tris(trimethylsilyl) titanacyclobutene. The authors have also employed this reaction in the modification of carbohydrates and cyclobutenediones. This olefination was also followed-up with subsequent transformations to produce carbocycles and heterocycles, including tetrahydrofurans and tetrahydropyrans.

  8. A three-membered ring approach to carbonyl olefination.

    Science.gov (United States)

    Niyomchon, Supaporn; Oppedisano, Alberto; Aillard, Paul; Maulide, Nuno

    2017-10-23

    The carbon-carbon double bond, with its diverse and multifaceted reactivity, occupies a prominent position in organic synthesis. Although a variety of simple alkenes are readily available, the mild and chemoselective introduction of a unit of unsaturation into a functionalized organic molecule remains an ongoing area of research, and the olefination of carbonyl compounds is a cornerstone of such approaches. Here we show the direct olefination of hydrazones via the intermediacy of three-membered ring species generated by addition of sulfoxonium ylides, departing from the general dogma of alkenes synthesis from carbonyls. Moreover, the mild reaction conditions and operational simplicity of the transformation render the methodology appealing from a practical point of view.

  9. Emissions of Toxic Carbonyls in an Electronic Cigarette

    Directory of Open Access Journals (Sweden)

    Guthery William

    2016-01-01

    Full Text Available Electronic cigarettes (e-cigs provide a smoke-free alternative for inhalation of nicotine without the vast array of toxic and carcinogenic combustion products produced by tobacco smoke. Elevated levels of toxic carbonyls may be generated during vaporisation; however, it is unclear whether that is indicative of a fault with the device or is due to the applied conditions of the test. A device, designed and built at this facility, was tested to determine the levels of selected toxic carbonyls. The reservoir was filled with approximately 960 mg of an e-liquid formulation containing 1.8% (w/v nicotine. Devices were puffed 200 times in blocks of 40 using a standardised regime consisting of a 55 mL puff volume; 3 s puff duration; 30 s puff interval; square wave puff profile. Confirmatory testing for nicotine and total aerosol delivery resulted in mean (n = 8 values of 10 mg (RSD 12.3% and 716 mg (RSD 11.2%, respectively. Emissions of toxic carbonyls were highly variable yet were between < 0.1% and 22.9% of expected levels from a Kentucky Reference Cigarette (K3R4F puffed 200 times under Health Canada Intense smoking conditions. It has been shown that a device built to a high specification with relatively consistent nicotine and aerosol delivery emits inconsistent levels of carbonyls. The exposure is greatly reduced when compared with lit tobacco products. However, it was observed that as the reservoirs neared depletion then emission levels were significantly higher

  10. Nucleophilic tetrafluoroethylation of carbonyl compounds with fluorinated sulfones

    Czech Academy of Sciences Publication Activity Database

    Václavík, Jiří; Chernykh, Yana; Jurásek, Bronislav; Beier, Petr

    2015-01-01

    Roč. 169, Jan (2015), s. 24-31 ISSN 0022-1139 R&D Projects: GA ČR GAP207/11/0421 Grant - others:GA MŠk(CZ) ED3.2.00/08.0144; GA MŠk(CZ) LM2010005 Institutional support: RVO:61388963 Keywords : fluorine * tetrafluoroethylation * sulfones * nucleophilic addition * carbonyl compounds Subject RIV: CC - Organic Chemistry Impact factor: 2.213, year: 2015

  11. Magnetophoretic manipulation in microsystem using carbonyl iron-polydimethylsiloxane microstructures

    OpenAIRE

    Faivre, Magalie; Gelszinnis, Renaud; Degouttes, Jérôme; Terrier, Nicolas; Rivière, Charlotte; Ferrigno, Rosaria; Deman, Anne-Laure

    2014-01-01

    This paper reports the use of a recent composite material, noted hereafter i-PDMS, made of carbonyl iron microparticles mixed in a PolyDiMethylSiloxane (PDMS) matrix, for magnetophoretic functions such as capture and separation of magnetic species. We demonstrated that this composite which combine the advantages of both components, can locally generate high gradients of magnetic field when placed between two permanent magnets. After evaluating the magnetic susceptibility of the material as a ...

  12. Promoting Recruitment using Information Management Efficiently (PRIME): a stepped-wedge, cluster randomised trial of a complex recruitment intervention embedded within the REstart or Stop Antithrombotics Randomised Trial.

    Science.gov (United States)

    Maxwell, Amy E; Parker, Richard A; Drever, Jonathan; Rudd, Anthony; Dennis, Martin S; Weir, Christopher J; Al-Shahi Salman, Rustam

    2017-12-28

    Few interventions are proven to increase recruitment in clinical trials. Recruitment to RESTART, a randomised controlled trial of secondary prevention after stroke due to intracerebral haemorrhage, has been slower than expected. Therefore, we sought to investigate an intervention to boost recruitment to RESTART. We conducted a stepped-wedge, cluster randomised trial of a complex intervention to increase recruitment, embedded within the RESTART trial. The primary objective was to investigate if the PRIME complex intervention (a recruitment co-ordinator who conducts a recruitment review, provides access to bespoke stroke audit data exports, and conducts a follow-up review after 6 months) increases the recruitment rate to RESTART. We included 72 hospital sites located in England, Wales, or Scotland that were active in RESTART in June 2015. All sites began in the control state and were allocated using block randomisation stratified by hospital location (Scotland versus England/Wales) to start the complex intervention in one of 12 different months. The primary outcome was the number of patients randomised into RESTART per month per site. We quantified the effect of the complex intervention on the primary outcome using a negative binomial, mixed model adjusting for site, December/January months, site location, and background time trends in recruitment rate. We recruited and randomised 72 sites and recorded their monthly recruitment to RESTART over 24 months (March 2015 to February 2017 inclusive), providing 1728 site-months of observations for the primary analysis. The adjusted rate ratio for the number of patients randomised per month after allocation to the PRIME complex intervention versus control time before allocation to the PRIME complex intervention was 1.06 (95% confidence interval 0.55 to 2.03, p = 0.87). Although two thirds of respondents to the 6-month follow-up questionnaire agreed that the audit reports were useful, only six patients were reported to

  13. Complexes and aggregates of chlorophylls

    NARCIS (Netherlands)

    Kooyman, R.P.H.

    1980-01-01

    Chlorophyll (Chl) molecules can form complexes in two important ways: by ligation at the magnesium atom and/or by hydrogen bonding at the keto- carbonyl group. Under certain conditions these processes may give rise to dimer formation. This thesis describes some properties of complexes and dimers of

  14. Metodologia AGOA: a modelagem de clusters de hidratação no complexo aziridina···ácido fluorídrico AGOA methodology: modeling the hydration clusters for the aziridine···hydrofluoric complex

    Directory of Open Access Journals (Sweden)

    Boaz G. Oliveira

    2009-01-01

    Full Text Available We present a theoretical study of solvent effect on C2H5N···HF hydrogen-bonded complex through the application of the AGOA methodology. By using the TIP4P model to orientate the configuration of water molecules, the hydration clusters generated by AGOA were obtained through the analysis of the molecular electrostatic potential (MEP of solute (C2H5N···HF. Thereby, it was calculated the hydration energies on positive and negative MEP fields, which are maxima (PEMmax and minima (PEMmin when represent the -CH2- methylene groups and hydrofluoric acid, respectively. By taking into account the higher and lower hydration energy values of -370.6 kJ mol-1 and -74.3 kJ mol-1 for PEMmax and PEMmin of the C2H5N···HF, our analysis shows that these results corroborate the open ring reaction of aziridine, in which the preferential attack of water molecules occurs at the methylene groups of this heterocyclic.

  15. Carbonyl compounds in gas and particle phases of mainstream cigarette smoke

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Xiaobing, E-mail: pangxbyuanj@gmail.com [Department of Chemistry, University of York, Heslington, York, YO10 5DD (United Kingdom); Lewis, Alastair C., E-mail: ally.lewis@york.ac.uk [National Centre for Atmospheric Science, University of York, Heslington, York, YO10 5DD (United Kingdom)

    2011-11-01

    Carbonyl compounds (carbonyls) are important constituents of cigarette smoke and some are toxic and may be carcinogenic or mutagenic to humans. In this study carbonyl emissions in the gas and particle phases of mainstream cigarette smoke were assessed by GC-MS with pentafluorophenyl hydrazine (PFPH) derivatization. Seven brands of cigarettes and one brand of cigar common in the UK market and having differing nicotine, tar and carbon monoxide yields were investigated. Sixteen carbonyl components were identified in gaseous emissions and twenty in the particle phase. In the gaseous emissions, acetaldehyde presented as the predominant species, followed by formaldehyde, 2-propenal, and pentanal. In the particulate emissions, 1-hydroxy-2-propanone was the most abundant followed by formaldehyde, benzaldehyde, and 2,5-dimethylbenzaldehyde. Significant differences were found in carbonyl emissions among the brands of cigarettes. The gaseous carbonyl emissions varied in the range of 216-405 {mu}g cigarette{sup -1} ({mu}g cig{sup -1}) and the particulate carbonyl emissions varied in the range of 23-127 {mu}g cig{sup -1}. Positive correlations were found between the total emission of carbonyls, tar yield and carbon monoxide yield. Similar gas/particle (G/P) partitioning ratios of carbonyls were found among all cigarettes, which implies that G/P partitions of carbonyls in smoke mainly depend on the physical properties of the carbonyls. The gaseous carbonyl emissions were enhanced by 40% to 130% when some of the water, accounting for 8-12% of cigarettes in mass, was removed from the tobacco. Non-filtered cigarettes showed significantly higher carbonyl emissions compared to their filtered equivalents. Carbonyl particulate accounted for 11-19% by mass of total particulate matter from tobacco smoke. The cigar generated 806 {mu}g cig{sup -1} gaseous and 141 {mu}g cig{sup -1} particulate carbonyls, which is 2-4 times greater than the cigarettes. - Highlights: {yields} Carbonyl

  16. Carbonyl compounds in gas and particle phases of mainstream cigarette smoke

    International Nuclear Information System (INIS)

    Pang, Xiaobing; Lewis, Alastair C.

    2011-01-01

    Carbonyl compounds (carbonyls) are important constituents of cigarette smoke and some are toxic and may be carcinogenic or mutagenic to humans. In this study carbonyl emissions in the gas and particle phases of mainstream cigarette smoke were assessed by GC-MS with pentafluorophenyl hydrazine (PFPH) derivatization. Seven brands of cigarettes and one brand of cigar common in the UK market and having differing nicotine, tar and carbon monoxide yields were investigated. Sixteen carbonyl components were identified in gaseous emissions and twenty in the particle phase. In the gaseous emissions, acetaldehyde presented as the predominant species, followed by formaldehyde, 2-propenal, and pentanal. In the particulate emissions, 1-hydroxy-2-propanone was the most abundant followed by formaldehyde, benzaldehyde, and 2,5-dimethylbenzaldehyde. Significant differences were found in carbonyl emissions among the brands of cigarettes. The gaseous carbonyl emissions varied in the range of 216-405 μg cigarette -1 (μg cig -1 ) and the particulate carbonyl emissions varied in the range of 23-127 μg cig -1 . Positive correlations were found between the total emission of carbonyls, tar yield and carbon monoxide yield. Similar gas/particle (G/P) partitioning ratios of carbonyls were found among all cigarettes, which implies that G/P partitions of carbonyls in smoke mainly depend on the physical properties of the carbonyls. The gaseous carbonyl emissions were enhanced by 40% to 130% when some of the water, accounting for 8-12% of cigarettes in mass, was removed from the tobacco. Non-filtered cigarettes showed significantly higher carbonyl emissions compared to their filtered equivalents. Carbonyl particulate accounted for 11-19% by mass of total particulate matter from tobacco smoke. The cigar generated 806 μg cig -1 gaseous and 141 μg cig -1 particulate carbonyls, which is 2-4 times greater than the cigarettes. - Highlights: → Carbonyl emission factors in both gas (16 species) and

  17. Titanium Insertion into CO Bonds in Anionic Ti-CO2 Complexes.

    Science.gov (United States)

    Dodson, Leah G; Thompson, Michael C; Weber, J Mathias

    2018-03-22

    We explore the structures of [Ti(CO 2 ) y ] - cluster anions using infrared photodissociation spectroscopy and quantum chemistry calculations. The existence of spectral signatures of metal carbonyl CO stretching modes shows that insertion of titanium atoms into C-O bonds represents an important reaction during the formation of these clusters. In addition to carbonyl groups, the infrared spectra show that the titanium center is coordinated to oxalato, carbonato, and oxo ligands, which form along with the metal carbonyls. The presence of a metal oxalato ligand promotes C-O bond insertion in these systems. These results highlight the affinity of titanium for C-O bond insertion processes.

  18. Ambient levels of carbonyl compounds and their sources in Guangzhou, China

    Science.gov (United States)

    Feng, Yanli; Wen, Sheng; Chen, Yingjun; Wang, Xinming; Lü, Huixiong; Bi, Xinhui; Sheng, Guoying; Fu, Jiamo

    Ambient levels of carbonyl compounds and their possible sources, vehicular exhaust and cooking exhaust, were studied at seven places in Guangzhou, including five districts (a residential area, an industrial area, a botanical garden, a downtown area and a semi-rural area), a bus station and a restaurant during the period of June-September 2003. Nineteen carbonyl compounds were identified in the ambient air, of which acetone was the most abundant carbonyl, followed by formaldehyde and acetaldehyde. Only little changes were found in carbonyl concentration levels in the five different districts because of their dispersion and mixture in the atmosphere in summer. The lower correlations between the carbonyls' concentrations might result from the mixture of carbonyls derived from different sources, including strong photochemical reactions at noon in summer. Formaldehyde and acetaldehyde were the main carbonyls in bus station, while straight-chain carbonyls were comparatively abundant in cooking exhaust. Besides vehicular exhaust, cooking might be another major source of carbonyl compounds in Guangzhou City, especially for high molecular weight carbonyls.

  19. A method of detecting carbonyl compounds in tree leaves in China.

    Science.gov (United States)

    Huang, Juan; Feng, Yanli; Fu, Jiamo; Sheng, Guoying

    2010-06-01

    Carbonyl compounds have been paid more and more attention because some carbonyl species have been proven to be carcinogenic or a risk for human health. Plant leaves are both an important emission source and an important sink of carbonyl compounds. But the research on carbonyl compounds from plant leaves is very scarce. In order to make an approach to the emission mechanism of plant leaves, a new method was established to extract carbonyl compounds from fresh plant leaves. The procedure combining derivatization with ultrasonication was developed for the fast extraction of carbonyl compounds from tree leaves. Fresh leaves (Metasequoia glyptostroboides), were selected and extracted by this method. Seven carbonyl compounds, including formaldehyde, acetaldehyde, acetone, acrolein, p-tolualdehyde, m/o-tolualdehyde, and hexaldehyde were determined and quantified. The most common carbonyl species of the four tree leaves were formaldehyde, acrolein, and m/o-tolualdehyde. They accounted for 67.3% in cedar, 50.8% in sweet olive, 45.8% in dawn redwood, and 44.6% in camphor tree, respectively. Camphor tree had the highest leaf level of m/o-tolualdehyde with 15.0 +/- 3.4 microg g(-1)(fresh leaf weight), which indicated that camphor tree may be a bioindicator of the level of tolualdehyde or xylene in the atmosphere. By analyzing carbonyl compounds from different tree leaves, it is not only helpful for further studying the relationship between sink and emission of carbonyls from plants, but also helpful for exploring optimum plant population in urban greening.

  20. Determination of Carbonyl Functional Groups in Bio-oils by Potentiometric Titration: The Faix Method.

    Science.gov (United States)

    Black, Stuart; Ferrell, Jack R

    2017-02-07

    Carbonyl compounds present in bio-oils are known to be responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls cause an increase in viscosity (often referred to as 'aging') during storage of bio-oils. As such, carbonyl content has previously been used as a method of tracking bio-oil aging and condensation reactions with less variability than viscosity measurements. Additionally, carbonyls are also responsible for coke formation in bio-oil upgrading processes. Given the importance of carbonyls in bio-oils, accurate analytical methods for their quantification are very important for the bio-oil community. Potentiometric titration methods based on carbonyl oximation have long been used for the determination of carbonyl content in pyrolysis bio-oils. Here, we present a modification of the traditional carbonyl oximation procedures that results in less reaction time, smaller sample size, higher precision, and more accurate carbonyl determinations. While traditional carbonyl oximation methods occur at room temperature, the Faix method presented here occurs at an elevated temperature of 80 °C.

  1. Spanning Tree Based Attribute Clustering

    DEFF Research Database (Denmark)

    Zeng, Yifeng; Jorge, Cordero Hernandez

    2009-01-01

    Attribute clustering has been previously employed to detect statistical dependence between subsets of variables. We propose a novel attribute clustering algorithm motivated by research of complex networks, called the Star Discovery algorithm. The algorithm partitions and indirectly discards...... inconsistent edges from a maximum spanning tree by starting appropriate initial modes, therefore generating stable clusters. It discovers sound clusters through simple graph operations and achieves significant computational savings. We compare the Star Discovery algorithm against earlier attribute clustering...

  2. Multimorbidity Patterns in the Elderly: A New Approach of Disease Clustering Identifies Complex Interrelations between Chronic Conditions

    Science.gov (United States)

    Schäfer, Ingmar; von Leitner, Eike-Christin; Schön, Gerhard; Koller, Daniela; Hansen, Heike; Kolonko, Tina; Kaduszkiewicz, Hanna; Wegscheider, Karl; Glaeske, Gerd; van den Bussche, Hendrik

    2010-01-01

    Objective Multimorbidity is a common problem in the elderly that is significantly associated with higher mortality, increased disability and functional decline. Information about interactions of chronic diseases can help to facilitate diagnosis, amend prevention and enhance the patients' quality of life. The aim of this study was to increase the knowledge of specific processes of multimorbidity in an unselected elderly population by identifying patterns of statistically significantly associated comorbidity. Methods Multimorbidity patterns were identified by exploratory tetrachoric factor analysis based on claims data of 63,104 males and 86,176 females in the age group 65+. Analyses were based on 46 diagnosis groups incorporating all ICD-10 diagnoses of chronic diseases with a prevalence ≥ 1%. Both genders were analyzed separately. Persons were assigned to multimorbidity patterns if they had at least three diagnosis groups with a factor loading of 0.25 on the corresponding pattern. Results Three multimorbidity patterns were found: 1) cardiovascular/metabolic disorders [prevalence female: 30%; male: 39%], 2) anxiety/depression/somatoform disorders and pain [34%; 22%], and 3) neuropsychiatric disorders [6%; 0.8%]. The sampling adequacy was meritorious (Kaiser-Meyer-Olkin measure: 0.85 and 0.84, respectively) and the factors explained a large part of the variance (cumulative percent: 78% and 75%, respectively). The patterns were largely age-dependent and overlapped in a sizeable part of the population. Altogether 50% of female and 48% of male persons were assigned to at least one of the three multimorbidity patterns. Conclusion This study shows that statistically significant co-occurrence of chronic diseases can be subsumed in three prevalent multimorbidity patterns if accounting for the fact that different multimorbidity patterns share some diagnosis groups, influence each other and overlap in a large part of the population. In recognizing the full complexity of

  3. Multimorbidity patterns in the elderly: a new approach of disease clustering identifies complex interrelations between chronic conditions.

    Directory of Open Access Journals (Sweden)

    Ingmar Schäfer

    full complexity of multimorbidity we might improve our ability to predict needs and achieve possible benefits for elderly patients who suffer from multimorbidity.

  4. Clusters and how to make it work : toolkit for cluster strategy

    NARCIS (Netherlands)

    Manickam, Anu; van Berkel, Karel

    2013-01-01

    Clusters are the magic answer to regional economic development. Firms in clusters are more innovative; cluster policy dominates EU policy; ‘top-sectors’ and excellence are the choice of national policy makers; clusters are ‘in’. But, clusters are complex, clusters are ‘messy’; there is no clear

  5. Barriers to and facilitators of implementing complex workplace dietary interventions: process evaluation results of a cluster controlled trial.

    Science.gov (United States)

    Fitzgerald, Sarah; Geaney, Fiona; Kelly, Clare; McHugh, Sheena; Perry, Ivan J

    2016-04-21

    Ambiguity exists regarding the effectiveness of workplace dietary interventions. Rigorous process evaluation is vital to understand this uncertainty. This study was conducted as part of the Food Choice at Work trial which assessed the comparative effectiveness of a workplace environmental dietary modification intervention and an educational intervention both alone and in combination versus a control workplace. Effectiveness was assessed in terms of employees' dietary intakes, nutrition knowledge and health status in four large manufacturing workplaces. The study aimed to examine barriers to and facilitators of implementing complex workplace interventions, from the perspectives of key workplace stakeholders and researchers involved in implementation. A detailed process evaluation monitored and evaluated intervention implementation. Interviews were conducted at baseline (27 interviews) and at 7-9 month follow-up (27 interviews) with a purposive sample of workplace stakeholders (managers and participating employees). Topic guides explored factors which facilitated or impeded implementation. Researchers involved in recruitment and data collection participated in focus groups at baseline and at 7-9 month follow-up to explore their perceptions of intervention implementation. Data were imported into NVivo software and analysed using a thematic framework approach. Four major themes emerged; perceived benefits of participation, negotiation and flexibility of the implementation team, viability and intensity of interventions and workplace structures and cultures. The latter three themes either positively or negatively affected implementation, depending on context. The implementation team included managers involved in coordinating and delivering the interventions and the researchers who collected data and delivered intervention elements. Stakeholders' perceptions of the benefits of participating, which facilitated implementation, included managers' desire to improve company

  6. Electromagnetic and Microwave Absorption Properties of Carbonyl Tetrapod-Shaped Zno Nanostructures Composite Coatings

    Science.gov (United States)

    Yu, Haibo; Qin, Hui; Huang, Yunhua

    2012-08-01

    CIP/T-ZnO/EP composite coatings with carbonyl iron powders (CIP) and tetrapodshaped ZnO (T-ZnO) nanostructures as absorbers, and epoxy resin (EP) as matrix were prepared. The complex permittivity, permeability and microwave absorption properties of the coatings were investigated in the frequency range of 2-18 GHz. The effects of the weight ratio (CIP/T-ZnO/EP), the thickness and the solidification temperature on microwave absorption properties were discussed. When the weight ratio (CIP/TZnO/ EP), the thickness and the solidification temperature is 28:2:22, 1.8 mm, and 10°C, respectively, the optimal wave absorption with the minimum reflection loss (RL) value of -22.38 dB at 15.67 GHz and the bandwidth (RLcoatings may have a promising application in Ku-band (12-18 GHz).

  7. Carbonyl Compounds Produced by Vaporizing Cannabis Oil Thinning Agents.

    Science.gov (United States)

    Troutt, William D; DiDonato, Matthew D

    2017-11-01

    Cannabis use has increased in the United States, particularly the use of vaporized cannabis oil, which is often mixed with thinning agents for use in vaporizing devices. E-cigarette research shows that heated thinning agents produce potentially harmful carbonyls; however, similar studies have not been conducted (1) with agents that are commonly used in the cannabis industry and (2) at temperatures that are appropriate for cannabis oil vaporization. The goal of this study was to determine whether thinning agents used in the cannabis industry produce potentially harmful carbonyls when heated to a temperature that is appropriate for cannabis oil vaporization. Four thinning agents (propylene glycol [PG], vegetable glycerin [VG], polyethylene glycol 400 [PEG 400], and medium chain triglycerides [MCT]) were heated to 230°C and the resulting vapors were tested for acetaldehyde, acrolein, and formaldehyde. Each agent was tested three times. Testing was conducted in a smoking laboratory. Carbonyl levels were measured in micrograms per puff block. Analyses showed that PEG 400 produced significantly higher levels of acetaldehyde and formaldehyde than PG, MCT, and VG. Formaldehyde production was also significantly greater in PG compared with MCT and VG. Acrolein production did not differ significantly across the agents. PG and PEG 400 produced high levels of acetaldehyde and formaldehyde when heated to 230°C. Formaldehyde production from PEG 400 isolate was particularly high, with one inhalation accounting for 1.12% of the daily exposure limit, nearly the same exposure as smoking one cigarette. Because PG and PEG 400 are often mixed with cannabis oil, individuals who vaporize cannabis oil products may risk exposure to harmful formaldehyde levels. Although more research is needed, consumers and policy makers should consider these potential health effects before use and when drafting cannabis-related legislation.

  8. Determination of Carbonyl Compounds in Cigarette Mainstream Smoke. The CORESTA 2010 Collaborative Study and Recommended Method

    Directory of Open Access Journals (Sweden)

    Intorp M

    2014-12-01

    Full Text Available A recommended method has been developed and published by CORESTA, applicable to the quantification of selected carbonyl compounds (acetaldehyde, formaldehyde, acetone, acrolein, methyl ethyl ketone, crotonaldehyde, propionaldehyde and butyraldehyde in cigarette mainstream smoke. The method involved smoke collection in impinger traps, derivatisation of carbonyls with 2,4-dinitrophenylhydrazine (DNPH, separation of carbonyl hydrazones by reversed phase high performance liquid chromatography and detection by ultra violet or diode array.

  9. Determination of carbonyl compounds in air by HPLC

    International Nuclear Information System (INIS)

    Garcia, S.; Perez, R.M.; Campos, A.; Gonzalez, D.

    1995-09-01

    A method for the determination of seven carbonyl compounds in air is presented. The procedure involve sampling of air by a Sep-Pak cartridge impregnated with 2,4-dinitrophenylhydrazine. Elution was done with 3 mL of acetonitrile and the eluate was diluted to 5 mL. The analysis was done by HPLC with UV detection and external standard method quantification. It has been achieved relative standard deviations about 5% and detection limits of 80 ng/cartridge for formaldehyde, acetaldehyde and acetone+acrolein. Three different types of samples (rural, urban, petrol emission) were successfully analyzed

  10. Determination of carbonyl compounds in air by HPLC

    International Nuclear Information System (INIS)

    Garcia, S.; Perez, R.M.; Campos, A.; Gonzalez, D.

    1995-01-01

    A method for the determination of seven carbonyl compounds in air is presented. The procedure involve sampling of air by a Sep-Pak Cartridge impregnated with 2,4-dinitrophenylhydrazine. Elution was done with 3 mL of acetonitrile and the eluate was diluted to 5 mL. The analysis was done by HPLC with UV detection and external standard method quantification. It has been achieved relative standard deviations about 5% and detection limits of 80 ng/cartridge for formaldehyde, acetaldehyde and acetoacetonitrile. Three different types of samples (rural, urban, petrol emission) were successfully analyzed. (Author) 12 refs

  11. Magnetic properties of carbonyl iron particles in magnetorheological fluids

    International Nuclear Information System (INIS)

    Gorodkin, S R; James, R O; Kordonski, W I

    2009-01-01

    Knowledge of the magnetic properties of dispersed magnetic particles is a prerequisite to the design an MR fluid with desired performance. A term specific susceptibility is introduced for characterization of particle susceptibility. The study was performed with the Bartington MS2B magnetic susceptibility system on small samples volume. Specific magnetic susceptibility of iron particles was found to be a linear function of median particle size. Structural change in the fluid, including particle organization, led to susceptibility drift and may affect fluid performance. It was shown that susceptibility data can be used for evaluation of the concentration of carbonyl iron particles in MR fluids.

  12. Cluster headache

    Science.gov (United States)

    Histamine headache; Headache - histamine; Migrainous neuralgia; Headache - cluster; Horton's headache; Vascular headache - cluster ... Doctors do not know exactly what causes cluster headaches. They ... (chemical in the body released during an allergic response) or ...

  13. A biotin enrichment strategy identifies novel carbonylated amino acids in proteins from human plasma

    DEFF Research Database (Denmark)

    Havelund, Jesper F; Wojdyla, Katarzyna; Davies, Michael J

    2017-01-01

    Protein carbonylation is an irreversible protein oxidation correlated with oxidative stress, various diseases and ageing. Here we describe a peptide-centric approach for identification and characterisation of up to 14 different types of carbonylated amino acids in proteins. The modified residues...... in vitro metal ion-catalysed oxidation. Furthermore, we assigned 133 carbonylated sites in 36 proteins in native human plasma protein samples. The optimised workflow enabled detection of 10 hitherto undetected types of carbonylated amino acids in proteins: aldehyde and ketone modifications of leucine...

  14. Ruthenium(ii)-catalyzed olefination via carbonyl reductive cross-coupling.

    Science.gov (United States)

    Wei, Wei; Dai, Xi-Jie; Wang, Haining; Li, Chenchen; Yang, Xiaobo; Li, Chao-Jun

    2017-12-01

    Natural availability of carbonyl groups offers reductive carbonyl coupling tremendous synthetic potential for efficient olefin synthesis, yet the catalytic carbonyl cross-coupling remains largely elusive. We report herein such a reaction, mediated by hydrazine under ruthenium(ii) catalysis. This method enables facile and selective cross-couplings of two unsymmetrical carbonyl compounds in either an intermolecular or intramolecular fashion. Moreover, this chemistry accommodates a variety of substrates, proceeds under mild reaction conditions with good functional group tolerance, and generates stoichiometric benign byproducts. Importantly, the coexistence of KO t Bu and bidentate phosphine dmpe is vital to this transformation.

  15. Increasing chlamydia screening tests in general practice: a modified Zelen prospective Cluster Randomised Controlled Trial evaluating a complex intervention based on the Theory of Planned Behaviour.

    Science.gov (United States)

    McNulty, Cliodna A M; Hogan, Angela H; Ricketts, Ellie J; Wallace, Louise; Oliver, Isabel; Campbell, Rona; Kalwij, Sebastian; O'Connell, Elaine; Charlett, Andre

    2014-05-01

    To determine if a structured complex intervention increases opportunistic chlamydia screening testing of patients aged 15-24 years attending English general practitioner (GP) practices. A prospective, Cluster Randomised Controlled Trial with a modified Zelen design involving 160 practices in South West England in 2010. The intervention was based on the Theory of Planned Behaviour (TPB). It comprised of practice-based education with up to two additional contacts to increase the importance of screening to GP staff and their confidence to offer tests through skill development (including videos). Practical resources (targets, posters, invitation cards, computer reminders, newsletters including feedback) aimed to actively influence social cognitions of staff, increasing their testing intention. Data from 76 intervention and 81 control practices were analysed. In intervention practices, chlamydia screening test rates were 2.43/100 15-24-year-olds registered preintervention, 4.34 during intervention and 3.46 postintervention; controls testing rates were 2.61/100 registered patients prior intervention, 3.0 during intervention and 2.82 postintervention. During the intervention period, testing in intervention practices was 1.76 times as great (CI 1.24 to 2.48) as controls; this persisted for 9 months postintervention (1.57 times as great, CI 1.27 to 2.30). Chlamydia infections detected increased in intervention practices from 2.1/1000 registered 15-24-year-olds prior intervention to 2.5 during the intervention compared with 2.0 and 2.3/1000 in controls (Estimated Rate Ratio intervention versus controls 1.4 (CI 1.01 to 1.93). This complex intervention doubled chlamydia screening tests in fully engaged practices. The modified Zelen design gave realistic measures of practice full engagement (63%) and efficacy of this educational intervention in general practice; it should be used more often. The trial was registered on the UK Clinical Research Network Study Portfolio database

  16. Carbonyl[4-(2,3-dimethylphenylaminopent-3-en-2-onato-κ2N,O](triphenylphosphine-κPrhodium(I

    Directory of Open Access Journals (Sweden)

    Gertruida J. S. Venter

    2009-11-01

    Full Text Available In the title compound, [Rh(C13H16NO(C18H15P(CO], the coordination geometry of the RhI atom is square-planar, formed by the coordinating N and O atoms of the bidentate enaminoketonate ligand, one C atom from the carbonyl group and a P atom from triphenylphosphine. The complex displays a 0.591 (3:0.409 (3 ratio disorder of the phenyl unit of the monoanionic N,O-bidentate ligand. Intramolecular hydrogen bonding is observed between a C—H group of the triphenylphosphine unit and the O atom of the enaminoketonate ligand.

  17. Thiosemicarbazone complexes of the platinum metals. A story of ...

    Indian Academy of Sciences (India)

    Unknown

    Thiosemicarbazone complexes; platinum metals; variable coordination; ... carbonylic carbon via one or two intervening atoms, D,N,S tricoordination usually takes .... modelling studies show that in this coordination mode, the phenyl ring of the.

  18. Composition of amino acid using carbon monoxide. Amide carbonylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Izawa, Kunisuke (Ajinomoto Co., Inc., Tokyo (Japan))

    1989-02-01

    Amide carbonylation reaction is a method to compose N-acyl-{alpha}-amino acid from aldehyde, carboxylic acid amide, and carbon monoxide in a phase and with high yield. Unlike the conventional Strecker reaction, this method does not use HCN which is in question on public pollution and does not require hydrolysis. This amide carbonylation reaction was discovered by Wakamatsu and others of Ajinomoto Co.,Ltd. Present application examples of this method are the composition of N-acetyl amino acid from the aldehyde class, the composition of N-Acyl amino acid from olefin, the composition of N-acyl or acetyl amino acid from the raw material of alcohol and the halide class, the composition of N-acyl or acetyl amino acid via the isomerization of epoxide and allyl alcohol, the composition of amino dicarboxylic acid, applying deoxidation of ring acid anhydride, the composition of N-acyl amino acid from the raw material of the amine class, the stereoselective composition of -substitution ring-{alpha}-amino acid, and the composition of amino aldehyde. 24 refs., 2 figs., 2 tabs.

  19. Synthesis of dimethyl carbonate by oxidative carbonylation of methanol

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B.G.; Han, M.S.; Kim, H.S.; Ahn, B.S.; Park, K.Y.

    1999-07-01

    Dimethyl carbonate (DMC) synthesis reaction by oxidative carbonylation of methanol has been studied using vapor phase flow reaction system in the presence of Cu-based catalysts. A series of Cu-based catalysts were prepared by the conventional impregnation method using activated carbon (AC) as support. The effect of various promoters and reaction conditions on the catalytic reactivities was intensively evaluated in terms of methanol conversion and DMC selectivity. The morphological change of catalysts during the reaction was also compared by X-ray diffraction and SEM analysis. Regardless of catalyst compositions, the optimal reaction temperature for oxidative carbonylation of methanol was found to be around 120--130 C. The reaction rate was too slow below 100 C, while too many by-products were produced above 150 C. Among the various catalysts employed, CuCl{sub 2}/NaOH/AC catalyst with the mole ratio of OH/Cu = 0.5--1.0 has shown the best catalytic performance, which appears to have a strong relationship with the formation of intermediate species, Cu{sub 2}(OH){sub 3}Cl.

  20. Clustering high dimensional data

    DEFF Research Database (Denmark)

    Assent, Ira

    2012-01-01

    High-dimensional data, i.e., data described by a large number of attributes, pose specific challenges to clustering. The so-called ‘curse of dimensionality’, coined originally to describe the general increase in complexity of various computational problems as dimensionality increases, is known...... to render traditional clustering algorithms ineffective. The curse of dimensionality, among other effects, means that with increasing number of dimensions, a loss of meaningful differentiation between similar and dissimilar objects is observed. As high-dimensional objects appear almost alike, new approaches...... for clustering are required. Consequently, recent research has focused on developing techniques and clustering algorithms specifically for high-dimensional data. Still, open research issues remain. Clustering is a data mining task devoted to the automatic grouping of data based on mutual similarity. Each cluster...

  1. N-Heterocyclic Carbene Coinage Metal Complexes of the Germanium-Rich Metalloid Clusters [Ge9R3]− and [Ge9RI2]2− with R = Si(iPr3 and RI = Si(TMS3

    Directory of Open Access Journals (Sweden)

    Felix S. Geitner

    2017-07-01

    Full Text Available We report on the synthesis of novel coinage metal NHC (N-heterocyclic carbene compounds of the germanium-rich metalloid clusters [Ge9R3]− and [Ge9RI2]2− with R = Si(iPr3 and RI = Si(TMS3. NHCDippCu{η3Ge9R3} with R = Si(iPr3 (1 represents a less bulky silyl group-substituted derivative of the known analogous compounds with R = Si(iBu3 or Si(TMS3. The coordination of the [NHCDippCu]+ moiety to the cluster unit occurs via one triangular face of the tri-capped trigonal prismatic [Ge9] cluster. Furthermore, a series of novel Zintl cluster coinage metal NHC compounds of the type (NHCM2{η3Ge9RI2} (RI = Si(TMS3 M = Cu, Ag and Au; NHC = NHCDipp or NHCMes is presented. These novel compounds represent a new class of neutral dinuclear Zintl cluster coinage metal NHC compounds, which are obtained either by the stepwise reaction of a suspension of K12Ge17 with Si(TMS3Cl and the coinage metal carbene complexes NHCMCl (M = Cu, Ag, Au, or via a homogenous reaction using the preformed bis-silylated cluster K2[Ge9(Si(TMS32] and the corresponding NHCMCl (M = Cu, Ag, Au complex. The molecular structures of NHCDippCu{η3Ge9(Si(iPr33} (1 and (NHCDippCu2{η3-Ge9(Si(TMS32} (2 were determined by single crystal X-ray diffraction methods. In 2, the coordination of the [NHCDippCu]+ moieties to the cluster unit takes place via both open triangular faces of the [Ge9] entity. Furthermore, all compounds were characterized by means of NMR spectroscopy (1H, 13C, 29Si and ESI-MS.

  2. Rh(I) -Catalyzed Intramolecular Carbonylative C-H/C-I Coupling of 2-Iodobiphenyls Using Furfural as a Carbonyl Source.

    Science.gov (United States)

    Furusawa, Takuma; Morimoto, Tsumoru; Nishiyama, Yasuhiro; Tanimoto, Hiroki; Kakiuchi, Kiyomi

    2016-08-19

    Synthesis of fluoren-9-ones by a Rh-catalyzed intramolecular C-H/C-I carbonylative coupling of 2-iodobiphenyls using furfural as a carbonyl source is presented. The findings indicate that the rate-determining step is not a C-H bond cleavage but, rather, the oxidative addition of the C-I bond to a Rh(I) center. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Maternal aging affects oocyte resilience to carbonyl cyanide-m-chlorophenylhydrazone -induced mitochondrial dysfunction in cows.

    Directory of Open Access Journals (Sweden)

    Kazuki Kansaku

    Full Text Available Mitochondrial quality control is important for maintaining cellular and oocyte viability. In addition, aging affects mitochondrial quality in many cell types. In the present study, we examined how aging affects oocyte mitochondrial biogenesis and degeneration in response to induced mitochondrial dysfunction. Cumulus oocyte complexes were harvested from the ovaries of young (21‒45 months and aged (≥120 months cows and treated for 2 hours with 10 μM carbonyl cyanide-m- chlorophenylhydrazone (CCCP, or a vehicle control, after which cumulus oocyte complexes were subjected to in vitro fertilization and culture. CCCP treatment reduced ATP content and increased reactive oxygen species (ROS levels in the oocytes of both young and aged cows. When CCCP-treated cumulus oocyte complexes were subsequently cultured for 19 hours and/or subjected to fertilization, high ROS levels in oocytes and a low rate of blastocyst development was observed in oocytes derived from aged cows. In addition, we observed differential responses in mitochondrial biogenesis to CCCP treatment between young and aged cows. CCCP treatment enhanced mitochondrial biogenesis concomitant with upregulation of SIRT1 expression in oocytes of young, but not aged, cows. In conclusion, aging affects mitochondrial quality control and recuperation of oocytes following CCCP-induced mitochondrial dysfunction.

  4. Weighted Clustering

    DEFF Research Database (Denmark)

    Ackerman, Margareta; Ben-David, Shai; Branzei, Simina

    2012-01-01

    We investigate a natural generalization of the classical clustering problem, considering clustering tasks in which different instances may have different weights.We conduct the first extensive theoretical analysis on the influence of weighted data on standard clustering algorithms in both...... the partitional and hierarchical settings, characterizing the conditions under which algorithms react to weights. Extending a recent framework for clustering algorithm selection, we propose intuitive properties that would allow users to choose between clustering algorithms in the weighted setting and classify...

  5. Data clustering algorithms and applications

    CERN Document Server

    Aggarwal, Charu C

    2013-01-01

    Research on the problem of clustering tends to be fragmented across the pattern recognition, database, data mining, and machine learning communities. Addressing this problem in a unified way, Data Clustering: Algorithms and Applications provides complete coverage of the entire area of clustering, from basic methods to more refined and complex data clustering approaches. It pays special attention to recent issues in graphs, social networks, and other domains.The book focuses on three primary aspects of data clustering: Methods, describing key techniques commonly used for clustering, such as fea

  6. Preparation and microwave shielding property of silver-coated carbonyl iron powder

    International Nuclear Information System (INIS)

    Cao, Xiao Guo; Ren, Hao; Zhang, Hai Yan

    2015-01-01

    Highlights: • The silver-coated carbonyl iron powder is prepared by the electroless plating process. • The silver-coated carbonyl iron powder is a new kind of conductive filler. • The reflection and absorption dominate the shielding mechanism of the prepared powder. • Increasing the thickness of electroconductive adhesive will increase the SE. - Abstract: Electroless silver coating of carbonyl iron powder is demonstrated in the present investigation. The carbonyl iron powders are characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) before and after the coating process. The relatively uniform and continuous silver coating is obtained under the given coating conditions. In this paper, the electromagnetic interference (EMI) shielding mechanism of the silver-coated carbonyl iron powder is suggested. The reflection of silver coating and absorption of carbonyl iron powder dominate the shielding mechanism of the silver-coated carbonyl iron powder. The silver-coated carbonyl iron powders are used as conductive filler in electroconductive adhesive for electromagnetic interference shielding applications. The effect of the thickness of electroconductive adhesive on the shielding effectiveness (SE) is investigated. The results indicate that the SE increases obviously with the increase of the thickness of electroconductive adhesive. The SE of the electroconductive adhesive with 0.35 mm thickness is above 38 dB across the tested frequency range

  7. Comparison of carbonyl compounds emissions from diesel engine fueled with biodiesel and diesel

    Science.gov (United States)

    He, Chao; Ge, Yunshan; Tan, Jianwei; You, Kewei; Han, Xunkun; Wang, Junfang; You, Qiuwen; Shah, Asad Naeem

    The characteristics of carbonyl compounds emissions were investigated on a direct injection, turbocharged diesel engine fueled with pure biodiesel derived from soybean oil. The gas-phase carbonyls were collected by 2,4-dinitrophenylhydrazine (DNPH)-coated silica cartridges from diluted exhaust and analyzed by HPLC with UV detector. A commercial standard mixture including 14 carbonyl compounds was used for quantitative analysis. The experimental results indicate that biodiesel-fueled engine almost has triple carbonyls emissions of diesel-fueled engine. The weighted carbonyls emission of 8-mode test cycle of biodiesel is 90.8 mg (kW h) -1 and that of diesel is 30.7 mg (kW h) -1. The formaldehyde is the most abundant compound of carbonyls for both biodiesel and diesel, taking part for 46.2% and 62.7% respectively. The next most significant compounds are acetaldehyde, acrolein and acetone for both fuels. The engine fueled with biodiesel emits a comparatively high content of propionaldehyde and methacrolein. Biodiesel, as an alternative fuel, has lower specific reactivity (SR) caused by carbonyls compared with diesel. When fueled with biodiesel, carbonyl compounds make more contribution to total hydrocarbon emission.

  8. Protein carbonyl content: a novel biomarker for aging in HIV/AIDS patients

    Directory of Open Access Journals (Sweden)

    Vaishali Kolgiri

    2017-01-01

    Conclusions: Carbonyl content may has a role as a biomarker for detecting oxidative DNA damage induced ART toxicity and/or accelerated aging in HIV/AIDS patients. Larger studies are warranted to elucidate the role of carbonyl content as a biomarker for premature aging in HIV/AIDS patients.

  9. Design and fabrication of microfluidic mixer from carbonyl iron–PDMS composite membrane

    KAUST Repository

    Li, Jiaxing; Zhang, Mengying; Wang, Limu; Li, Weihua; Sheng, Ping; Wen, Weijia

    2010-01-01

    This paper introduces a carbonyl iron-PDMS (CI-PDMS) composite magnetic elastomer in which carbonyl iron (CI) particles are uniformly distributed in a PDMS matrix. The CI particles and the PDMS were mixed at different weight ratios and tested

  10. Metal-atom fluorescence from the quenching of metastable rare gases by metal carbonyls

    International Nuclear Information System (INIS)

    Hollingsworth, W.E.

    1982-11-01

    A flowing afterglow apparatus was used to study the metal fluorescence resulting from the quenching of metastable rare-gas states by metal carbonyls. The data from the quenching or argon, neon, and helium by iron and nickel carbonyl agreed well with a restricted degree of freedom model indicating a concerted bond-breaking dissociation

  11. The food choice at work study: effectiveness of complex workplace dietary interventions on dietary behaviours and diet-related disease risk - study protocol for a clustered controlled trial.

    Science.gov (United States)

    Geaney, Fiona; Scotto Di Marrazzo, Jessica; Kelly, Clare; Fitzgerald, Anthony P; Harrington, Janas M; Kirby, Ann; McKenzie, Ken; Greiner, Birgit; Perry, Ivan J

    2013-11-06

    Dietary behaviour interventions have the potential to reduce diet-related disease. Ample opportunity exists to implement these interventions in the workplace. The overall aim is to assess the effectiveness and cost-effectiveness of complex dietary interventions focused on environmental dietary modification alone or in combination with nutrition education in large manufacturing workplace settings. A clustered controlled trial involving four large multinational manufacturing workplaces in Cork will be conducted. The complex intervention design has been developed using the Medical Research Council's framework and the National Institute for Health and Clinical Excellence (NICE) guidelines and will be reported using the TREND statement for the transparent reporting of evaluations with non-randomized designs. It will draw on a soft paternalistic 'nudge' theoretical perspective. It will draw on a soft paternalistic "nudge" theoretical perspective. Nutrition education will include three elements: group presentations, individual nutrition consultations and detailed nutrition information. Environmental dietary modification will consist of five elements: (a) restriction of fat, saturated fat, sugar and salt, (b) increase in fibre, fruit and vegetables, (c) price discounts for whole fresh fruit, (d) strategic positioning of healthier alternatives and (e) portion size control. No intervention will be offered in workplace A (control). Workplace B will receive nutrition education. Workplace C will receive nutrition education and environmental dietary modification. Workplace D will receive environmental dietary modification alone. A total of 448 participants aged 18 to 64 years will be selected randomly. All permanent, full-time employees, purchasing at least one main meal in the workplace daily, will be eligible. Changes in dietary behaviours, nutrition knowledge, health status with measurements obtained at baseline and at intervals of 3 to 4 months, 7 to 9 months and 13 to 16

  12. The food choice at work study: effectiveness of complex workplace dietary interventions on dietary behaviours and diet-related disease risk - study protocol for a clustered controlled trial

    Science.gov (United States)

    2013-01-01

    Background Dietary behaviour interventions have the potential to reduce diet-related disease. Ample opportunity exists to implement these interventions in the workplace. The overall aim is to assess the effectiveness and cost-effectiveness of complex dietary interventions focused on environmental dietary modification alone or in combination with nutrition education in large manufacturing workplace settings. Methods/design A clustered controlled trial involving four large multinational manufacturing workplaces in Cork will be conducted. The complex intervention design has been developed using the Medical Research Council’s framework and the National Institute for Health and Clinical Excellence (NICE) guidelines and will be reported using the TREND statement for the transparent reporting of evaluations with non-randomized designs. It will draw on a soft paternalistic “nudge” theoretical perspective. Nutrition education will include three elements: group presentations, individual nutrition consultations and detailed nutrition information. Environmental dietary modification will consist of five elements: (a) restriction of fat, saturated fat, sugar and salt, (b) increase in fibre, fruit and vegetables, (c) price discounts for whole fresh fruit, (d) strategic positioning of healthier alternatives and (e) portion size control. No intervention will be offered in workplace A (control). Workplace B will receive nutrition education. Workplace C will receive nutrition education and environmental dietary modification. Workplace D will receive environmental dietary modification alone. A total of 448 participants aged 18 to 64 years will be selected randomly. All permanent, full-time employees, purchasing at least one main meal in the workplace daily, will be eligible. Changes in dietary behaviours, nutrition knowledge, health status with measurements obtained at baseline and at intervals of 3 to 4 months, 7 to 9 months and 13 to 16 months will be recorded. A process

  13. Protein carbonylation and metal-catalyzed protein oxidation in a cellular perspective

    DEFF Research Database (Denmark)

    Møller, Ian Max; Rogowska-Wrzesinska, Adelina; Rao, R S P

    2011-01-01

    Proteins can become oxidatively modified in many different ways, either by direct oxidation of amino acid side chains and protein backbone or indirectly by conjugation with oxidation products of polyunsaturated fatty acids and carbohydrates. While reversible oxidative modifications are thought...... to be relevant in physiological processes, irreversible oxidative modifications are known to contribute to cellular damage and disease. The most well-studied irreversible protein oxidation is carbonylation. In this work we first examine how protein carbonylation occurs via metal-catalyzed oxidation (MCO) in vivo...... and in vitro with an emphasis on cellular metal ion homeostasis and metal binding. We then review proteomic methods currently used for identifying carbonylated proteins and their sites of modification. Finally, we discuss the identified carbonylated proteins and the pattern of carbonylation sites in relation...

  14. Development of an automatic sampling device for the continuous measurement of atmospheric carbonyls compounds

    International Nuclear Information System (INIS)

    Perraud, V.

    2007-12-01

    Two sampling strategies were studied to develop an automatic instrument for the continuous measurement of atmospheric carbonyl compounds. Because of its specificity towards carbonyls compounds, sampling by using a transfer of gaseous phase in a liquid phase associated with a simultaneous chemical derivatization of the trapped compounds was first studied. However, this method do not allow a quantitative sampling of all studied carbonyl compounds, nor a continuous measurement in the field. To overcome the difficulties, a second strategy was investigated: the cryogenic adsorption onto solid adsorbent followed by thermodesorption and a direct analysis by GC/MS. Collection efficiency using different solid adsorbents was found greater than 95% for carbonyl compounds consisting of 1 to 7 carbons. This work is a successful first step towards the realization of the automatic sampling device for a continuous measurement of atmospheric carbonyls compounds. (author)

  15. Impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls generation

    Science.gov (United States)

    Lin, Chi-Chi; Chen, Hsuan-Yu

    2014-06-01

    This study aims at detecting ozone removal rates and corresponding carbonyls generated by ozone reaction with HVAC filters from various building, i.e., shopping mall, school, and office building. Studies were conducted in a small-scale environmental chamber. By examining dust properties including organic carbon proportion and specific surface area of dusts adsorbed on filters along with ozone removal rates and carbonyls generation rate, the relationship among dust properties, ozone removal rates, and carbonyls generation was identified. The results indicate a well-defined positive correlation between ozone removal efficiency and carbonyls generation on filters, as well as a positive correlation among the mass of organic carbon on filters, ozone removal efficiency and carbonyls generations.

  16. A Theoretical Investigation of the Plausibility of Reactions Between Ammonia and Carbonyl Species (Formaldehyde, Acetaldehyde, and Acetone) in Interstellar Ice Analogs at Ultracold Temperatures

    Science.gov (United States)

    Chen, Lina; Woon, David E.

    2011-01-01

    We have reexamined the reaction between formaldehyde and ammonia, which was previously studied by us and other workers in modestly sized cluster calculations. Larger model systems with up to 12H2O were employed, and reactions of two more carbonyl species, acetaldehyde and acetone, were also carried out. Calculations were performed at the B3LYP/6-31+G** level with bulk solvent effects treated with a polarizable continuum model; limited MP2/6-31+G** calculations were also performed. We found that while the barrier for the concerted proton relay mechanism described in previous work remains modest, it is still prohibitively high for the reaction to occur under the ultracold conditions that prevail in dense interstellar clouds. However, a new pathway emerged in more realistic clusters that involves at least one barrierless step for two of the carbonyl species considered here: ammonia reacts with formaldehyde and acetaldehyde to form a partial charge transfer species in small clusters (4H2O) and a protonated hydroxyamino intermediate species in large clusters (9H2O, 12H2O); modest barriers that decrease sharply with cluster size are found for the analogous processes for the acetone-NH3 reaction. Furthermore, if a second ammonia replaces one of the water molecules in calculations in the 9H2O clusters, deprotonation can occur to yield the same neutral hydroxyamino species that is formed via the original concerted proton relay mechanism. In at least one position, deprotonation is barrierless when zero-point energy is included. In addition to describing the structures and energetics of the reactions between formaldehyde, acetaldehyde, and acetone with ammonia, we report spectroscopic predictions of the observable vibrational features that are expected to be present in ice mixtures of different composition.

  17. Activation of heterogenised rhodium carbonylation catalyst infrared spectroscopic study

    Energy Technology Data Exchange (ETDEWEB)

    Scurrell, M S

    1977-01-01

    In a study related to heterogeneous versions of homogeneous catalysts active in carbonylation of methanol to acetic acid, the catalyst consisted of 1Vertical Bar3< rhodium as rhodium trichloride supported on 13X zeolite and evacuated at 437/sup 0/K. Contacting the catalyst with carbon monoxide caused two bands, at 2025 and 2095 cm/sup -1/, to appear. Contact with a mixture of carbon monoxide and methyl iodide (the usual promoter) caused bands at 2085, 1710, 1440, and 1370 cm/sup -1/ to appear; the first two correspond to the bands at 2062 and 1711 cm/sup -1/ in homogeneous catalysts attributed to the formation of Rh(CH/sup 3/CO)(CO)X/sup 2/I/sup -/. Spectra.

  18. SILP catalysis in gas-phase hydroformylation and carbonylation

    Energy Technology Data Exchange (ETDEWEB)

    Riisager, A.; Fehrmann, R. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemistry; Haumann, M.; Wasserscheid, P. [Univ. Erlangen-Nuernberg (Germany). Lehrstuhl fuer Chemische Reaktionstechnik

    2006-07-01

    Supported ionic liquid phase (SILP) catalysts are new materials consisting of an ionic liquid-metal catalyst solution highly dispersed on a porous support. The use of a non-volatile, ionic liquid catalyst phase in SILP catalysts results in a stable heterogeneous-type material with selectivity and efficiency like homogeneous catalysts. The silica-supported SILP Rh-bisphosphine hydroformylation catalyst exhibited good activities and excellent selectivities in gas phase hydroformylation with stability exceeding 700 hours time-on-stream. Spectroscopic and kinetic data confirmed the homogeneous nature of the catalyst. In the Rh- SILP catalysed carbonylation of methanol the formation of undesired by-products could be suppressed by variation of residence time and gas pressure. (orig.)

  19. Cluster management.

    Science.gov (United States)

    Katz, R

    1992-11-01

    Cluster management is a management model that fosters decentralization of management, develops leadership potential of staff, and creates ownership of unit-based goals. Unlike shared governance models, there is no formal structure created by committees and it is less threatening for managers. There are two parts to the cluster management model. One is the formation of cluster groups, consisting of all staff and facilitated by a cluster leader. The cluster groups function for communication and problem-solving. The second part of the cluster management model is the creation of task forces. These task forces are designed to work on short-term goals, usually in response to solving one of the unit's goals. Sometimes the task forces are used for quality improvement or system problems. Clusters are groups of not more than five or six staff members, facilitated by a cluster leader. A cluster is made up of individuals who work the same shift. For example, people with job titles who work days would be in a cluster. There would be registered nurses, licensed practical nurses, nursing assistants, and unit clerks in the cluster. The cluster leader is chosen by the manager based on certain criteria and is trained for this specialized role. The concept of cluster management, criteria for choosing leaders, training for leaders, using cluster groups to solve quality improvement issues, and the learning process necessary for manager support are described.

  20. Architecture of the Yeast Mitochondrial Iron-Sulfur Cluster Assembly Machinery: THE SUB-COMPLEX FORMED BY THE IRON DONOR, Yfh1 PROTEIN, AND THE SCAFFOLD, Isu1 PROTEIN.

    Science.gov (United States)

    Ranatunga, Wasantha; Gakh, Oleksandr; Galeano, Belinda K; Smith, Douglas Y; Söderberg, Christopher A G; Al-Karadaghi, Salam; Thompson, James R; Isaya, Grazia

    2016-05-06

    The biosynthesis of Fe-S clusters is a vital process involving the delivery of elemental iron and sulfur to scaffold proteins via molecular interactions that are still poorly defined. We reconstituted a stable, functional complex consisting of the iron donor, Yfh1 (yeast frataxin homologue 1), and the Fe-S cluster scaffold, Isu1, with 1:1 stoichiometry, [Yfh1]24·[Isu1]24 Using negative staining transmission EM and single particle analysis, we obtained a three-dimensional reconstruction of this complex at a resolution of ∼17 Å. In addition, via chemical cross-linking, limited proteolysis, and mass spectrometry, we identified protein-protein interaction surfaces within the complex. The data together reveal that [Yfh1]24·[Isu1]24 is a roughly cubic macromolecule consisting of one symmetric Isu1 trimer binding on top of one symmetric Yfh1 trimer at each of its eight vertices. Furthermore, molecular modeling suggests that two subunits of the cysteine desulfurase, Nfs1, may bind symmetrically on top of two adjacent Isu1 trimers in a manner that creates two putative [2Fe-2S] cluster assembly centers. In each center, conserved amino acids known to be involved in sulfur and iron donation by Nfs1 and Yfh1, respectively, are in close proximity to the Fe-S cluster-coordinating residues of Isu1. We suggest that this architecture is suitable to ensure concerted and protected transfer of potentially toxic iron and sulfur atoms to Isu1 during Fe-S cluster assembly. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Determination of bond energies by mass spectrometry. Some transition metal carbonyls

    International Nuclear Information System (INIS)

    Michels, G.D.

    1979-01-01

    Two groups of transition metal carbonyls have been studied, M(CO) 6 and M(CO) 5 CS complexes of the Group VIB metals and M 2 (CO) 10 complexes of the Group VIIB metals. Results for the hexacarbonyl complexes indicate that the measured fragmentation energies are in error by 0.25 +- 0.02 eV per CO produced. This is attributed to excitation of CO to the first vibrational state. Least-squares dissociation energies calculated from corrected data for M(CO) 5 CS complexes indicate that the M--CS bond is 3 to 4 times stronger than the M--CO bonds. Substitution of CS for CO in going from M(CO) 6 to M(CO) 5 CS weakens the remaining M--CO bonds by an average of 0.2 eV. Previously unreported MnTc(CO) 10 and TcRe(CO) 10 are prepared by halide substitution of Tc(CO) 5 Br and Re(CO) 5 Br with Mn(CO) 5 - and Tc(CO) 5 - , respectively. In the positive ion, metal and mixed-metal decacarbonyls are considered as (CO) 5 M + --M(CO) 5 complexes possessing five strong and five weak M--CO bonds. For Mn 2 (CO) 10 and Re 2 (CO) 10 , M + --M dissociation energies are 3.0 +- 0.1 and 4.0 +- 0.3 eV, respectively. These energies are 2.5 times greater than those reported for homolytic cleavage to M(CO) 5 + and M(CO) 5

  2. Dimers of fluorinated methanes with carbonyl sulfide: the rotational spectrum and structure of difluoromethane-OCS.

    Science.gov (United States)

    Serafin, Michal M; Peebles, Sean A

    2008-12-11

    The pure rotational spectra of four isotopologues of the difluoromethane-carbonyl sulfide dimer have been measured in the 5-15 GHz region with use of pulsed-nozzle Fourier-transform microwave spectroscopy. The complex was determined to possess an ab plane of symmetry with a center of mass separation of 3.41(2) A and dipole moment components mu(a) = 1.1386(18) D, mu(b) = 0.4840(63) D, mu(total) = 1.2372(41) D. Experimental planar moments indicate that the two fluorine atoms straddle the symmetry plane while one of the C-H bonds of the difluoromethane monomer is aligned to interact with the oxygen atom of the OCS molecule. The assignment of the rotational spectrum for this dimer completes the experimental studies of the series of dimers involving fluorinated methanes (HCF(3), H(2)CF(2), and H(3)CF) complexed with OCS and makes possible a comparison of properties within this series.

  3. Isotopic clusters

    International Nuclear Information System (INIS)

    Geraedts, J.M.P.

    1983-01-01

    Spectra of isotopically mixed clusters (dimers of SF 6 ) are calculated as well as transition frequencies. The result leads to speculations about the suitability of the laser-cluster fragmentation process for isotope separation. (Auth.)

  4. Cluster Headache

    Science.gov (United States)

    ... a role. Unlike migraine and tension headache, cluster headache generally isn't associated with triggers, such as foods, hormonal changes or stress. Once a cluster period begins, however, drinking alcohol ...

  5. Clusters and exotic processes

    International Nuclear Information System (INIS)

    Schiffer, J.P.

    1975-01-01

    An attempt is made to present some data which may be construed as indicating that perhaps clusters play a role in high energy and exotic pion or kaon interactions with complex (A much greater than 16) nuclei. Also an attempt is made to summarize some very recent experimental work on pion interactions with nuclei which may or may not in the end support a picture in which clusters play an important role. (U.S.)

  6. Molecular complexes of tungsten oxotetrachloride with azomethins

    International Nuclear Information System (INIS)

    Abramenko, Yu.V.; Garnovskij, A.D.; Abramenko, V.A.; Medvedeva, T.E.

    1992-01-01

    Series of new molecular complexes of tungsten oxotetrachloride with benza- and salicylalimines of equimolar compositions obtained. Substances are studied using element analysis, IR spectroscopy and conductometry. Octahedral structure of complexes with central atom coordination of benzalaniline molecules via azomethin nitrogen atom, and salicylalimines - via carbonyl oxygen atom of quinoid tantometric form of ligand is assumed

  7. Cluster Headache

    OpenAIRE

    Pearce, Iris

    1985-01-01

    Cluster headache is the most severe primary headache with recurrent pain attacks described as worse than giving birth. The aim of this paper was to make an overview of current knowledge on cluster headache with a focus on pathophysiology and treatment. This paper presents hypotheses of cluster headache pathophysiology, current treatment options and possible future therapy approaches. For years, the hypothalamus was regarded as the key structure in cluster headache, but is now thought to be pa...

  8. Categorias Cluster

    OpenAIRE

    Queiroz, Dayane Andrade

    2015-01-01

    Neste trabalho apresentamos as categorias cluster, que foram introduzidas por Aslak Bakke Buan, Robert Marsh, Markus Reineke, Idun Reiten e Gordana Todorov, com o objetivo de categoriíicar as algebras cluster criadas em 2002 por Sergey Fomin e Andrei Zelevinsky. Os autores acima, em [4], mostraram que existe uma estreita relação entre algebras cluster e categorias cluster para quivers cujo grafo subjacente é um diagrama de Dynkin. Para isto desenvolveram uma teoria tilting na estrutura triang...

  9. Active control of methanol carbonylation selectivity over Au/carbon anode by electrochemical potential.

    Science.gov (United States)

    Funakawa, Akiyasu; Yamanaka, Ichiro; Otsuka, Kiyoshi

    2005-05-12

    Electrochemical oxidative carbonylation of methanol was studied over Au supported carbon anode in CO. The major carbonylation products were dimethyl oxalate (DMO) and dimethyl carbonate (DMC). The minor oxidation products were dimethoxy methane (DMM) and methyl formate (MF) from methanol and CO(2). Influences of various reaction conditions were studied on carbonylation activities and selectivities. The selectivities to DMO and DMC can be controlled by the electrochemical potential. Electrocatalysis of Au/carbon anode was studied by cyclic voltammetry (CV), stoichiometric reactions among Au(3+), methanol, and CO, and UV-vis spectra. The Au/carbon anode was characterized by XRD, SEM, and BE images before and after the carbonylation. These experimental facts strongly suggest that transition of oxidation states of Au affects changing of the carbonylation selectivities to DMO and DMC. Au(0) is the active species for the selective DMO formation by direct electrochemical carbonylation at low potentials (selective DMC formation by indirect electrochemical carbonylation through Au(3+)/Au(+) redox at high potentials (>+1.3 V).

  10. Protein carbonylation sites in bovine raw milk and processed milk products.

    Science.gov (United States)

    Milkovska-Stamenova, Sanja; Mnatsakanyan, Ruzanna; Hoffmann, Ralf

    2017-08-15

    During thermal treatment of milk, proteins are oxidized, which may reduce the nutritional value of milk, abolish protein functions supporting human health, especially important for newborns, and yield potentially harmful products. The side chains of several amino acids can be oxidized to reactive carbonyls, which are often used to monitor oxidative stress in organisms. Here we mapped protein carbonylation sites in raw milk and different brands of pasteurized, ultra high temperature (UHT) treated milk, and infant formulas (IFs) after digesting the precipitated proteins with trypsin. Reactive carbonyls were derivatized with O-(biotinylcarbazoylmethyl)hydroxylamine to enrich the modified peptides by avidin-biotin affinity chromatography and analyze them by nanoRP-UPLC-ESI-MS. Overall, 53 unique carbonylated peptides (37 carbonylation sites, 15 proteins) were identified. Most carbonyls were derived from dicarbonyls (mainly glyoxal). The number of carbonylation sites increased with the harsher processing from raw milk (4) to pasteurized (16) and UHT milk (16) and to IF (24). Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Application of balanced scorecard in the evaluation of a complex health system intervention: 12 months post intervention findings from the BHOMA intervention: a cluster randomised trial in Zambia.

    Science.gov (United States)

    Mutale, Wilbroad; Stringer, Jeffrey; Chintu, Namwinga; Chilengi, Roma; Mwanamwenge, Margaret Tembo; Kasese, Nkatya; Balabanova, Dina; Spicer, Neil; Lewis, James; Ayles, Helen

    2014-01-01

    In many low income countries, the delivery of quality health services is hampered by health system-wide barriers which are often interlinked, however empirical evidence on how to assess the level and scope of these barriers is scarce. A balanced scorecard is a tool that allows for wider analysis of domains that are deemed important in achieving the overall vision of the health system. We present the quantitative results of the 12 months follow-up study applying the balanced scorecard approach in the BHOMA intervention with the aim of demonstrating the utility of the balanced scorecard in evaluating multiple building blocks in a trial setting. The BHOMA is a cluster randomised trial that aims to strengthen the health system in three rural districts in Zambia. The intervention aims to improve clinical care quality by implementing practical tools that establish clear clinical care standards through intensive clinic implementations. This paper reports the findings of the follow-up health facility survey that was conducted after 12 months of intervention implementation. Comparisons were made between those facilities in the intervention and control sites. STATA version 12 was used for analysis. The study found significant mean differences between intervention(I) and control (C) sites in the following domains: Training domain (Mean I:C; 87.5.vs 61.1, mean difference 23.3, p = 0.031), adult clinical observation domain (mean I:C; 73.3 vs.58.0, mean difference 10.9, p = 0.02 ) and health information domain (mean I:C; 63.6 vs.56.1, mean difference 6.8, p = 0.01. There was no gender differences in adult service satisfaction. Governance and motivation scores did not differ between control and intervention sites. This study demonstrates the utility of the balanced scorecard in assessing multiple elements of the health system. Using system wide approaches and triangulating data collection methods seems to be key to successful evaluation of such complex health

  12. Meaningful Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; Calapristi, Augustin J.; Crow, Vernon L.; Hetzler, Elizabeth G.; Turner, Alan E.

    2004-05-26

    We present an approach to the disambiguation of cluster labels that capitalizes on the notion of semantic similarity to assign WordNet senses to cluster labels. The approach provides interesting insights on how document clustering can provide the basis for developing a novel approach to word sense disambiguation.

  13. Horticultural cluster

    OpenAIRE

    SHERSTIUK S.V.; POSYLAYEVA K.I.

    2013-01-01

    In the article there are the theoretical and methodological approaches to the nature and existence of the cluster. The cluster differences from other kinds of cooperative and integration associations. Was develop by scientific-practical recommendations for forming a competitive horticultur cluster.

  14. Text Clustering Algorithm Based on Random Cluster Core

    Directory of Open Access Journals (Sweden)

    Huang Long-Jun

    2016-01-01

    Full Text Available Nowadays clustering has become a popular text mining algorithm, but the huge data can put forward higher requirements for the accuracy and performance of text mining. In view of the performance bottleneck of traditional text clustering algorithm, this paper proposes a text clustering algorithm with random features. This is a kind of clustering algorithm based on text density, at the same time using the neighboring heuristic rules, the concept of random cluster is introduced, which effectively reduces the complexity of the distance calculation.

  15. Synthesis and Characterization of Tc(I) Carbonyl Nitrosyl Species Relevant to the Hanford Tank Waste: FY 2016 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Gabriel B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Martin, Thibaut J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wall, Nathalie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walter, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-24

    Among long-lived radioactive constituents in the Hanford tank waste, Tc presents a unique challenge in that it exists predominantly in the liquid phase, generally in the anionic form of pertechnetate, TcO4-, which is highly volatile at low-activity waste (LAW) vitrification melter temperatures and mobile in the Hanford site’s subsurface environment. The complex behavior of Tc under storage, treatment, and immobilization conditions significantly affects its management options, which to-date remain uncertain. In strongly alkaline environments, Tc exists as pertechnetate, TcO4- (oxidation state +7), and in the reduced forms (oxidation state < +7) collectively known as non-pertechnetate species. Pertechnetate is a well-characterized, anionic Tc species that can be removed from LAW by anion exchange or solvent extraction methods. There is no definitive information on the origin of the non-pertechnetate Tc species, nor is there a comprehensive description of their composition and behavior. It has been recently proposed that the non-pertechnetate species can comprise Tc(I) metal center and carbonyl or mixed carbonyl nitrosyl ligands stabilizing low-valent Tc. Recent work by our group has significantly expanded this previous work, generating a series of Tc(I) carbonyl compounds and demonstrating that they can be generated from reduction of TcO4- in the simulated Hanford tank waste in presence of CO at elevated temperature (Levitskaia et al. 2014). These results are consistent with the previous proposal that [Tc(CO)3]+ species can be present in the Hanford tank waste and suggest that the low Tc(I) oxidation state is stabilized by the π-accepting ability of the CO ligands. The continuation work has been initiated to develop model Tc carbonyl nitrosyl compounds and investigate their potential presence in the Hanford tank wastes. This report summarizes our to-date results.

  16. The Emergence of Manganese-Based Carbonyl Hydrosilylation Catalysts.

    Science.gov (United States)

    Trovitch, Ryan J

    2017-11-21

    In recent years, interest in homogeneous manganese catalyst development has intensified because of the earth-abundant and nontoxic nature of this metal. Although compounds of Mn have largely been utilized for epoxidation reactions, recent efforts have revealed that Mn catalysts can mediate a broad range of reductive transformations. Low-valent Mn compounds have proven to be particularly effective for the hydrosilylation of carbonyl- and carboxylate-containing substrates, and this Account aims to highlight my research group's contributions to this field. In our initial 2014 communication, we reported that the bis(imino)pyridine-supported compound ( Ph2PPr PDI)Mn mediates ketone hydrosilylation with exceptional activity under solvent-free conditions. Silanes including Ph 2 SiH 2 , (EtO) 3 SiH, (EtO) 2 MeSiH, and (EtO)Me 2 SiH were found to partially reduce cyclohexanone in the presence of ( Ph2PPr PDI)Mn, while turnover frequencies of up to 1280 min -1 were observed using PhSiH 3 . This led us to evaluate the hydrosilylation of 11 additional ketones and allowed for the atom-efficient preparation of tertiary and quaternary silanes. At that time, it was also discovered that ( Ph2PPr PDI)Mn catalyzes the dihydrosilylation of esters (by way of acyl C-O bond hydrosilylation) to yield a mixture of silyl ethers with modest activity. Earlier this year, the scope of these transformations was extended to aldehydes and formates, and the observed hydrosilylation activities are among the highest obtained for any transition-metal catalyst. The effectiveness of three related catalysts has also been evaluated: ( Ph2PPr PDI)MnH, ( PyEt PDEA)Mn, and [( Ph2PEt PDI)Mn] 2 . To our surprise, ( Ph2PPr PDI)MnH was found to exhibit higher carboxylate dihydrosilylation activity than ( Ph2PPr PDI)Mn, while ( PyEt PDEA)Mn demonstrated remarkable carbonyl hydrosilylation activity considering that it lacks a redox-active supporting ligand. The evaluation of [( Ph2PEt PDI)Mn] 2 revealed

  17. Cluster Matters

    DEFF Research Database (Denmark)

    Gulati, Mukesh; Lund-Thomsen, Peter; Suresh, Sangeetha

    2018-01-01

    sell their products successfully in international markets, but there is also an increasingly large consumer base within India. Indeed, Indian industrial clusters have contributed to a substantial part of this growth process, and there are several hundred registered clusters within the country...... of this handbook, which focuses on the role of CSR in MSMEs. Hence we contribute to the literature on CSR in industrial clusters and specifically CSR in Indian industrial clusters by investigating the drivers of CSR in India’s industrial clusters....

  18. Low pressure carbonylation of benzyl chloride = Die carbonylierung von benzylchlorid bei niedrigen drücken

    OpenAIRE

    Luggenhorst, H.J.; Westerterp, K.R.

    1986-01-01

    For carbonylations, metal carbonyls, particularly cobalt and iron carbonyls, are often used as catalysts. These reactions take place under rather drastic reaction conditions, e.g. 200–300 °C and 60–100 MPa. In some patents it is stated that similar reactions using the same catalysts can also be carried out under rather mild reaction conditions, such as 0–100 °C and 0–2.5 MPa. We studied the conversion of benzyl chloride to phenyl acetic methyl ester in a semi-batch reactor in which one of the...

  19. Mechanistic differences between methanol and dimethyl ether carbonylation in side pockets and large channels of mordenite.

    Science.gov (United States)

    Boronat, Mercedes; Martínez, Cristina; Corma, Avelino

    2011-02-21

    The activity and selectivity towards carbonylation presented by Brønsted acid sites located inside the 8MR pockets or in the main 12MR channels of mordenite is studied by means of quantum-chemical calculations, and the mechanistic differences between methanol and DME carbonylation are investigated. The selectivity towards carbonylation is higher inside the 8MR pockets, where the competitive formation of DME and hydrocarbons that finally leads to catalyst deactivation is sterically impeded. Moreover, inclusion of dispersion interactions in the calculations leads to agreement between the calculated activation barriers for the rate determining step and the experimentally observed higher reactivity of methoxy groups located inside the 8MR channels.

  20. Formation of neutral and charged gold carbonyls on highly facetted gold nanostructures

    Science.gov (United States)

    Chau, Thoi-Dai; Visart de Bocarmé, Thierry; Kruse, Norbert; Wang, Richard L. C.; Kreuzer, Hans Jürgen

    2003-12-01

    We show that gold mono- and di-carbonyls are formed on gold field emitter tips during interaction with carbon monoxide gas at room temperature and in the presence of high electrostatic fields. The experiments are done in a time-of-flight atom probe to obtain mass spectra. The yield of monocarbonyl cations is about twice that of di-carbonyl ions. Density functional theory calculations are reported that explain the field stabilization of adsorbed carbonyls and the desorption yield of their cations.

  1. Carbonylation of 1-hexene in the presence of palladium-anion-exchange resin catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, A.L.; Pirozhkov, S.D.; Buiya, M.A.; Lunin, A.F.; Karapetyan, L.P.; Saldadze, K.M.

    1986-06-20

    Activated charcoal, silica gel, and zeolites containing palladium are active in the carbonylation of lower olefins by carbon monoxide. In the present work, they studied the carbonylation of 1-hexene in the presence of a series of palladium catalysts containing An-221, An-251, and AN-511 anion-exchange catalysts produced in the USSR as the supports. A catalyst obtained by the deposition of palladium(II) on weakly basic anion-exchange resins displays high efficiency in the carbonylation of 1-hexene with the formation of a nixture of enanthoic and 2-methylcaproic acids.

  2. Carbonyl(N-nitroso-N-oxido-1-naphtylamine-κ2O,O′(triphenylphosphine-κPrhodium(I acetone solvate

    Directory of Open Access Journals (Sweden)

    T. J. Muller

    2009-12-01

    Full Text Available The title compound, [Rh(C10H7N2O2(C18H15P(CO]·(CH32CO, is the second structural report of a metal complex formed with the O,O′-C10H7N2O2 (neocupferrate ligand. In the crystal structure, the metal centre is surrounded by one carbonyl ligand, one triphenylphosphine ligand and the bidentate neocupferrate ligand, forming a distorted square-planar RhCO2P coordination set which is best illustrated by the small O—Rh—O bite angle of 77.74 (10°. There are no classical hydrogen-bond interactions observed for this complex.

  3. Thermal characterization of magnetically aligned carbonyl iron/agar composites.

    Science.gov (United States)

    Diaz-Bleis, D; Vales-Pinzón, C; Freile-Pelegrín, Y; Alvarado-Gil, J J

    2014-01-01

    Composites of magnetic particles into polymeric matrices have received increasing research interest due to their capacity to respond to external magnetic or electromagnetic fields. In this study, agar from Gelidium robustum has been chosen as natural biocompatible polymer to build the matrix of the magnetic carbonyl iron particles (CIP) for their uses in biomedical fields. Heat transfer behavior of the CIP-agar composites containing different concentrations (5, 10, 15, 20, 25 and 30% w/w) of magnetically aligned and non-aligned CIP in the agar matrix was studied using photothermal radiometry (PTR) in the back-propagation emission configuration. The morphology of the CIP-agar composites with aligned and non-aligned CIP under magnetic field was also evaluated by scanning electron microscopy (SEM). The results revealed a dominant effect of CIP concentration over the alignment patterns induced by the magnetic field, which agrees with the behavior of the thermal diffusivity and thermal conductivity. Agar served as a perfect matrix to be used with CIP, and CIP-agar composites magnetically aligned at 20% CIP concentration can be considered as promising 'smart' material for hyperthermia treatments in the biomedical field. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. The oceanic cycle and global atmospheric budget of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, P.S.

    1994-12-31

    A significant portion of stratospheric air chemistry is influenced by the existence of carbonyl sulfide (COS). This ubiquitous sulfur gas represents a major source of sulfur to the stratosphere where it is converted to sulfuric acid aerosol particles. Stratospheric aerosols are climatically important because they scatter incoming solar radiation back to space and are able to increase the catalytic destruction of ozone through gas phase reactions on particle surfaces. COS is primarily formed at the surface of the earth, in both marine and terrestrial environments, and is strongly linked to natural biological processes. However, many gaps in the understanding of the global COS cycle still exist, which has led to a global atmospheric budget that is out of balance by a factor of two or more, and a lack of understanding of how human activity has affected the cycling of this gas. The goal of this study was to focus on COS in the marine environment by investigating production/destruction mechanisms and recalculating the ocean-atmosphere flux.

  5. Plant Uptake of Atmospheric Carbonyl Sulfide in Coast Redwood Forests

    Science.gov (United States)

    Campbell, J. E.; Whelan, M. E.; Berry, J. A.; Hilton, T. W.; Zumkehr, A.; Stinecipher, J.; Lu, Y.; Kornfeld, A.; Seibt, U.; Dawson, T. E.; Montzka, S. A.; Baker, I. T.; Kulkarni, S.; Wang, Y.; Herndon, S. C.; Zahniser, M. S.; Commane, R.; Loik, M. E.

    2017-12-01

    The future resilience of coast redwoods (Sequoia sempervirens) is now of critical concern due to the detection of a 33% decline in California coastal fog over the 20th century. However, ecosystem-scale measurements of photosynthesis and stomatal conductance are challenging in coast redwood forests, making it difficult to anticipate the impacts of future changes in fog. To address this methodological problem, we explore coastal variations in atmospheric carbonyl sulfide (COS or OCS), which could potentially be used as a tracer of these ecosystem processes. We conducted atmospheric flask campaigns in coast redwood sites, sampling at surface heights and in the canopy ( 70 m), at the University of California Landels-Hill Big Creek Reserve and Big Basin State Park. We simulated COS atmosphere-biosphere exchange with a high-resolution 3-D model to interpret these data. Flask measurements indicated a persistent daytime drawdown between the coast and the downwind forest (45 ± 6 ppt COS) that is consistent with the expected relationship between COS plant uptake, stomatal conductance, and gross primary production. Other sources and sinks of COS that could introduce noise to the COS tracer technique (soils, anthropogenic activity, nocturnal plant uptake, and surface hydrolysis on leaves) are likely to be small relative to daytime COS plant uptake. These results suggest that COS measurements may be useful for making ecosystem-scale estimates of carbon, water, and energy exchange in coast redwood forests.

  6. Catalytic hydrogenation of carbonyl group for deuterated compound production

    International Nuclear Information System (INIS)

    Gluhoi, C. Andreea; Marginean, P.; Lazar, Diana; Almasan, V.

    1999-01-01

    The total deuterated isopropyl alcohol can be produced starting from acetone. The developed technology comprises two steps: Deuteration of acetone by H/D isotopic exchange between acetone and heavy water in homogeneous catalysis. Reduction of the deuterated acetone with deuterium in presence of a metal/support catalyst. H/D isotopic exchange reaction of the H atoms from CH 3 groups is easy to occur because carbonyl group weakens C-H bond (ceto-enolyc tautomery). The big difference between boiling points of acetone and water permits an easy separation of acetone by distillation method. The reduction of acetone with deuterium was performed in a dynamic reactor by passing a deuterium flow saturated with acetone vapour through a supported nickel catalyst bed. The reaction products were analysed on-line using a flame ionisation detector. The supported nickel catalysts were checked for this reaction. By using nickel over different supports the selectivity for isopropyl alcohol was about 100%. The propane was detected only as traces. The catalytic activity depends strongly on the support nature: the Ni/SiO 2 is less active, while the Ni/TiO 2 presents the larger value for the intrinsic activity. (authors)

  7. Global gridded anthropogenic emissions inventory of carbonyl sulfide

    Science.gov (United States)

    Zumkehr, Andrew; Hilton, Tim W.; Whelan, Mary; Smith, Steve; Kuai, Le; Worden, John; Campbell, J. Elliott

    2018-06-01

    Atmospheric carbonyl sulfide (COS or OCS) is the most abundant sulfur containing gas in the troposphere and is an atmospheric tracer for the carbon cycle. Gridded inventories of global anthropogenic COS are used for interpreting global COS measurements. However, previous gridded anthropogenic data are a climatological estimate based on input data that is over three decades old and are not representative of current conditions. Here we develop a new gridded data set of global anthropogenic COS sources that includes more source sectors than previously available and uses the most current emissions factors and industry activity data as input. Additionally, the inventory is provided as annually varying estimates from years 1980-2012 and employs a source specific spatial scaling procedure. We estimate a global source in year 2012 of 406 Gg S y-1 (range of 223-586 Gg S y-1), which is highly concentrated in China and is twice as large as the previous gridded inventory. Our large upward revision in the bottom-up estimate of the source is consistent with a recent top-down estimate based on air-monitoring and Antarctic firn data. Furthermore, our inventory time trends, including a decline in the 1990's and growth after the year 2000, are qualitatively consistent with trends in atmospheric data. Finally, similarities between the spatial distribution in this inventory and remote sensing data suggest that the anthropogenic source could potentially play a role in explaining a missing source in the global COS budget.

  8. Relationship between laparoscopic cholecystectomy operative time and carbonyl hemoglobin content

    Directory of Open Access Journals (Sweden)

    ZHANG Qi

    2013-06-01

    Full Text Available ObjectiveTo investigate whether operative time of laparoscopic cholecystectomy impacts the carbonyl hemoglobin (COHb concentration in peripheral blood. MethodsForty patients with gallstones and indications for laparoscopic cholecystectomy were enrolled in the study. Peripheral venous blood samples were collected at the beginning and end of the operative procedure. COHb concentration was measured by UV spectroscopy. The significance of changes in COHb concentration in relation to time of the operative procedure (rounded to the nearest minute was assessed by statistical correlation coefficient test. ResultsThe laparoscopic procedure was completed in 38 cases, and two patients required conversion to laparotomy. The content of COHb in peripheral venous blood had significantly increased during the laparoscopic operation (operation beginning: 11.07%±1.18% vs. operation end: 1.44%±0.26%, P<0.05. The change was positively correlated with operation time (r=0.85. ConclusionCarbon monoxide produced during the laparoscopic cholecystectomy procedure can lead to an increase in peripheral venous blood COHb. The longer the operation lasts, the greater the increase in COHb.

  9. Efficient and selective α-bromination of carbonyl compounds with N-bromosuccinimide under microwave

    KAUST Repository

    Guan, Xiao-Yu; Al-Misba'a, Zahra; Huang, Kuo-Wei

    2014-01-01

    A highly efficient method for the synthesis of α-halocarbonyl compounds has been achieved via selective monobromination of aromatic and aliphatic carbonyl compounds with N-bromosuccinimide catalyzed by p-toluenesulfonic acid under microwave irradiation within 30 min.

  10. Structure and Bonding in Binuclear Metal Carbonyls. Classical Paradigms vs. Insights from Modern Theoretical Calculations

    Czech Academy of Sciences Publication Activity Database

    Ponec, Robert

    2015-01-01

    Roč. 1053, SI (2015), s. 195-213 ISSN 2210-271X Institutional support: RVO:67985858 Keywords : binuclear metal carbonyls * DAFH analysis * 18-electron rule Subject RIV: CC - Organic Chemistry Impact factor: 1.403, year: 2015

  11. Nanostructured palladium tailored via carbonyl chemical route towards oxygen reduction reaction

    International Nuclear Information System (INIS)

    Luo, Y.; Mora-Hernández, J.M.; Estudillo-Wong, L.A.; Arce-Estrada, E.M.; Alonso-Vante, N.

    2015-01-01

    Graphical Abstract: Mass-depending morphologies of nanostructured Palladium obtained via the carbonyl chemical route. Display Omitted -- Highlights: •Mass-depending morphology was observed in nanostructured palladium supported on carbon prepared by the carbonyl chemical route. •The Morphological effect of carbon supported Pd was investigated towards ORR. -- Abstract: Carbon supported palladium nanostructures were synthesized via the carbonyl chemical route. Compared with nanostructured platinum, prepared via carbonyl chemical route, Pd nanomaterials showed mass-loading morphology, whereas particle size and morphology of Pt nanostructures was constant. The oxygen reduction reaction (ORR) on nanostructured Pd, with different morphology in both acid and alkaline medium was investigated. A relationship, based on X-ray diffraction structural analysis pattern, transmission electron microscope, with the Pd morphological effect on ORR activity was identified

  12. Deuterium enrichment by selective photo-induced dissociation of an organic carbonyl compound

    International Nuclear Information System (INIS)

    Marling, J.B.

    1981-01-01

    A deuterium-enriched material is produced by selective photoinduced dissociation of a gas phase organic carbonyl compound containing at least one hydrogen atom bonded to an atom adjacent to a carbonyl group. Alkyl carbonyl compounds such as acetone, acetaldehyde, trifluoroacetic acid, cyclobutanone, cyclopentanone, methyl acetate, 3,3-dimethyl-2-butanone, 2,4-pentanedione, and 4-methyl-2-pentanone are preferred. The carbonyl compound is subjected to intense infrared radiation from one laser, or two lasers operating at different frequencies, to selectively dissociate the deuterated molecules into stable products. The undissociated compound may be redeuterated by direct aqueous liquid phase H/D exchange, or by indirect liquid phase exchange using an alkanol in an intermediate step

  13. Efficient and selective α-bromination of carbonyl compounds with N-bromosuccinimide under microwave

    KAUST Repository

    Guan, Xiao-Yu

    2014-02-07

    A highly efficient method for the synthesis of α-halocarbonyl compounds has been achieved via selective monobromination of aromatic and aliphatic carbonyl compounds with N-bromosuccinimide catalyzed by p-toluenesulfonic acid under microwave irradiation within 30 min.

  14. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Science.gov (United States)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  15. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Matthias, E-mail: matthias.schindler@physik.uni-erlangen.de; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-15

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO{sub 2} and reduced to graphite to determine {sup 14}C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  16. Data Clustering

    Science.gov (United States)

    Wagstaff, Kiri L.

    2012-03-01

    On obtaining a new data set, the researcher is immediately faced with the challenge of obtaining a high-level understanding from the observations. What does a typical item look like? What are the dominant trends? How many distinct groups are included in the data set, and how is each one characterized? Which observable values are common, and which rarely occur? Which items stand out as anomalies or outliers from the rest of the data? This challenge is exacerbated by the steady growth in data set size [11] as new instruments push into new frontiers of parameter space, via improvements in temporal, spatial, and spectral resolution, or by the desire to "fuse" observations from different modalities and instruments into a larger-picture understanding of the same underlying phenomenon. Data clustering algorithms provide a variety of solutions for this task. They can generate summaries, locate outliers, compress data, identify dense or sparse regions of feature space, and build data models. It is useful to note up front that "clusters" in this context refer to groups of items within some descriptive feature space, not (necessarily) to "galaxy clusters" which are dense regions in physical space. The goal of this chapter is to survey a variety of data clustering methods, with an eye toward their applicability to astronomical data analysis. In addition to improving the individual researcher’s understanding of a given data set, clustering has led directly to scientific advances, such as the discovery of new subclasses of stars [14] and gamma-ray bursts (GRBs) [38]. All clustering algorithms seek to identify groups within a data set that reflect some observed, quantifiable structure. Clustering is traditionally an unsupervised approach to data analysis, in the sense that it operates without any direct guidance about which items should be assigned to which clusters. There has been a recent trend in the clustering literature toward supporting semisupervised or constrained

  17. Native tandem and ion mobility mass spectrometry highlight structural and modular similarities in clustered-regularly-interspaced shot-palindromic-repeats (CRISPR)-associated protein complexes from Escherichia coli and Pseudomonas aeruginosa.

    Science.gov (United States)

    van Duijn, Esther; Barbu, Ioana M; Barendregt, Arjan; Jore, Matthijs M; Wiedenheft, Blake; Lundgren, Magnus; Westra, Edze R; Brouns, Stan J J; Doudna, Jennifer A; van der Oost, John; Heck, Albert J R

    2012-11-01

    The CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated genes) immune system of bacteria and archaea provides acquired resistance against viruses and plasmids, by a strategy analogous to RNA-interference. Key components of the defense system are ribonucleoprotein complexes, the composition of which appears highly variable in different CRISPR/Cas subtypes. Previous studies combined mass spectrometry, electron microscopy, and small angle x-ray scattering to demonstrate that the E. coli Cascade complex (405 kDa) and the P. aeruginosa Csy-complex (350 kDa) are similar in that they share a central spiral-shaped hexameric structure, flanked by associating proteins and one CRISPR RNA. Recently, a cryo-electron microscopy structure of Cascade revealed that the CRISPR RNA molecule resides in a groove of the hexameric backbone. For both complexes we here describe the use of native mass spectrometry in combination with ion mobility mass spectrometry to assign a stable core surrounded by more loosely associated modules. Via computational modeling subcomplex structures were proposed that relate to the experimental IMMS data. Despite the absence of obvious sequence homology between several subunits, detailed analysis of sub-complexes strongly suggests analogy between subunits of the two complexes. Probing the specific association of E. coli Cascade/crRNA to its complementary DNA target reveals a conformational change. All together these findings provide relevant new information about the potential assembly process of the two CRISPR-associated complexes.

  18. Colour removal and carbonyl by-production in high dose ozonation for effluent polishing.

    Science.gov (United States)

    Mezzanotte, V; Fornaroli, R; Canobbio, S; Zoia, L; Orlandi, M

    2013-04-01

    Experimental tests have been conducted to investigate the efficiency and the by-product generation of high dose ozonation (10-60 mg O3 L(-1)) for complete colour removal from a treated effluent with an important component of textile dyeing wastewater. The effluent is discharged into an effluent-dominated stream where no dilution takes place, and, thus, the quality requirement for the effluents is particularly strict. 30, 60 and 90 min contact times were adopted. Colour was measured as absorbance at 426, 558 and 660 nm wavelengths. pH was monitored throughout the experiments. The experimental work showed that at 50 mg L(-1) colour removal was complete and at 60 mg O3 L(-1) the final aldehyde concentration ranged between 0.72 and 1.02 mg L(-1). Glyoxal and methylglyoxal concentrations were directly related to colour removal, whereas formaldehyde, acetaldehyde, acetone and acrolein were not. Thus, the extent of colour removal can be used to predict the increase in glyoxal and methylglyoxal concentrations. As colour removal can be assessed by a simple absorbance measurement, in contrast to the analysis of specific carbonyl compounds, which is much longer and complex, the possibility of using colour removal as an indicator for predicting the toxic potential of ozone by-products for textile effluents is of great value. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Microwave absorbing property of a hybrid absorbent with carbonyl irons coating on the graphite

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yonggang, E-mail: xuyonggang221@163.com [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai, 200438 (China); Yan, Zhenqiang; Zhang, Deyuan [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2015-11-30

    Graphical abstract: The absorbing property could be enhanced as the CIPs coated on the graphite. - Highlights: • Absorbers filled with CIPs coating on the graphite was fabricated. • The permittivity and permeability increased as CIPs coated. • The CIP materials enhanced the electromagnetic property. • The graphite coated CIPs were effective in 2–18 GHz. - Abstract: The hybrid absorbent filled with carbonyl iron particles (CIPs) coating on the graphite was prepared using a chemical vapor decomposition (CVD) process. X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The complex permittivity and permeability were measured using a vector network analyzer in the frequency range of 2–18 GHz. The results showed that α-Fe appeared in the super-lattice diffraction peaks in XRD graph. The composites added CIPs coating on the graphite had a higher permittivity and imaginary permeability due to the superior microwave dielectric loss and magnetic loss of the CIPs. The reflection loss (RL) result showed that composites filled with 5 vol% Fe-graphite had an excellent absorbing property in the 2–18 GHz, the minimum RL was −25.14 dB at 6 mm and −26.52 dB at 8 mm, respectively.

  20. Microwave absorbing property of silicone rubber composites with added carbonyl iron particles and graphite platelet

    International Nuclear Information System (INIS)

    Xu, Yonggang; Zhang, Deyuan; Cai, Jun; Yuan, Liming; Zhang, Wenqiang

    2013-01-01

    Silicone rubber composites filled with carbonyl iron particles (CIPs) and graphite platelet (GP) were prepared using non-coating or coating processes. The complex permittivity and permeability of the composites were measured using a vector network analyzer in the frequency range of 1–18 GHz and dc electric conductivity was measured by the standard four-point contact method. The results showed that CIPs/GP composites fabricated in the coating process had the highest permittivity and permeability due to the particle orientation and interactions between the two absorbents. The coating process resulted in a decreased effective eccentricity of the absorbents, and the dc conductivity increased according to Neelakanta's equations. The reflection loss (RL) value showed that the composites had an excellent absorbing property in the L-band, minimum −11.85 dB at 1.5 mm and −15.02 dB at 2 mm. Thus, GP could be an effective additive in preparing thin absorbing composites in the L-band. - Highlights: ► The added GP increased the permittivity and permeability of composites filled with CIPs. ► The enhancement was owing to interactions of the two absorbents and the fabrication process. ► The coating process decreased the effective eccentricity of the particles, and increased the conductivity of the composites. ► The composites to which CIPs/GP were added in coating process had excellent absorbing properties in the L-band.

  1. Fluoride-Mediated Dephosphonylation of α-Diazo-β-carbonyl Phosphonates.

    Science.gov (United States)

    Phatake, Ravindra S; Mullapudi, Venkannababu; Wakchaure, Vivek C; Ramana, Chepuri V

    2017-01-20

    The possibility of fluoride-mediated selective dephosphonylation of α-diazo-β-carbonyl phosphonates such as the Ohira-Bestmann reagent has been proposed and executed. The resulting α-diazocarbonyl intermediates undergo a (3 + 2)-cycloaddition at room temperature with conjugated olefins and benzynes. Interestingly, under the current conditions, the resulting cycloaddition products underwent either N-acylation (with excess α-diazo-β-carbonyl phosphonates) or Michael addition (with conjugated olefins).

  2. Structure and Reactivity of Zeolite- and Carbon-Supported Catalysts for the Oxidative Carbonylation of Alcohols

    OpenAIRE

    Briggs, Daniel Neal

    2010-01-01

    AbstractStructure and Reactivity of Zeolite- and Carbon-Supported Catalysts for the Oxidative Carbonylation of AlcoholsbyDaniel Neal BriggsDoctor of Philosophy in Chemical EngineeringUniversity of California, BerkeleyProfessor Alexis T. Bell, Chair The oxidative carbonylation of alcohols to produce dialkyl carbonates is a process that takes place commercially in a slurry of cuprous chloride in the appropriate alcohol. While this process is chemically efficient, it incurs costs in terms of ene...

  3. Chemoselective Reduction and Alkylation of Carbonyl Functions Using Phosphonium Salts as an in Situ Protecting Groups.

    Science.gov (United States)

    Ohta, Reiya; Fujioka, Hiromichi

    2017-01-01

    Recent progress in the chemoselective reduction and alkylation of carbonyl functions using our in situ protection method is described. Methods that enable reversal or control of the reactivity of a carbonyl functional group are potentially useful. They open up new areas of synthetic organic chemistry and change the concept of retrosynthesis because they remove the need for complicated protection/deprotection sequences. In this account, we discuss the strategy and applications of our in situ protection method using phosphonium salts.

  4. Cytoprotective Effects of Pumpkin (Cucurbita Moschata) Fruit Extract against Oxidative Stress and Carbonyl Stress.

    Science.gov (United States)

    Shayesteh, Reyhaneh; Kamalinejad, Mohammad; Adiban, Hasan; Kardan, Azin; Keyhanfar, Fariborz; Eskandari, Mohammad Reza

    2017-10-01

    Background Diabetes mellitus is a chronic endocrine disorder that is associated with significant mortality and morbidity due to microvascular and macrovascular complications. Diabetes complications accompanied with oxidative stress and carbonyl stress in different organs of human body because of the increased generation of free radicals and impaired antioxidant defense systems. In the meantime, reactive oxygen species (ROS) and reactive carbonyl species (RCS) have key mediatory roles in the development and progression of diabetes complications. Therapeutic strategies have recently focused on preventing such diabetes-related abnormalities using different natural and chemical compounds. Pumpkin ( Cucurbita moschata ) is one of the most important vegetables in the world with a broad-range of pharmacological activities such as antihyperglycemic effect. Methods In the present study, the cytoprotective effects of aqueous extract of C. moschata fruit on hepatocyte cytotoxicity induced by cumene hydroperoxide (oxidative stress model) or glyoxal (carbonylation model) were investigated using freshly isolated rat hepatocytes. Results The extract of C. moschata (50 μg/ml) excellently prevented oxidative and carbonyl stress markers, including hepatocyte lysis, ROS production, lipid peroxidation, glutathione depletion, mitochondrial membrane potential collapse, lysosomal damage, and cellular proteolysis. In addition, protein carbonylation was prevented by C. moschata in glyoxal-induced carbonyl stress. Conclusion It can be concluded that C. moschata has cytoprotective effects in oxidative stress and carbonyl stress models and this valuable vegetable can be considered as a suitable herbal product for the prevention of toxic subsequent of oxidative stress and carbonyl stress seen in chronic hyperglycemia. © Georg Thieme Verlag KG Stuttgart · New York.

  5. Organocatalyzed α-Sulfenylation of carbonyl compounds using N-formly/Acyl Sulfenmides

    International Nuclear Information System (INIS)

    Noh, Hyeon Wan; Lee, Chan; Jang, Hye Young

    2017-01-01

    α-Sulfenylation of aldehydes and ketones using N-formyl and N-acyl sulfenamides, prepared by Cu-catalyzed aerobic coupling of amides and thiols, was achieved in the presence of cyclic secondary amine⋅HCl catalysts. To obtain various sulfur-functionalized carbonyl compounds, sulfenamides containing aromatic and aliphatic organosulfur were investigated. As carbonyl compounds, cyclic and acyclic ketones, 1,3-dicarbonyl compounds, and aldehydes were investigated, affording the desired α-sulfenylation products in good yields

  6. Organocatalyzed α-Sulfenylation of carbonyl compounds using N-formly/Acyl Sulfenmides

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Hyeon Wan; Lee, Chan; Jang, Hye Young [Dept. of Energy Systems Research, Ajou University, Suwon (Korea, Republic of)

    2017-03-15

    α-Sulfenylation of aldehydes and ketones using N-formyl and N-acyl sulfenamides, prepared by Cu-catalyzed aerobic coupling of amides and thiols, was achieved in the presence of cyclic secondary amine⋅HCl catalysts. To obtain various sulfur-functionalized carbonyl compounds, sulfenamides containing aromatic and aliphatic organosulfur were investigated. As carbonyl compounds, cyclic and acyclic ketones, 1,3-dicarbonyl compounds, and aldehydes were investigated, affording the desired α-sulfenylation products in good yields.

  7. Plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids

    OpenAIRE

    Sedlačík, M.; Pavlínek, V.; Lehocký, M.; Mráček, A.; Grulich, O.; Švrčinová, P. (Petra); Filip, P. (Petr); Vesel, A.

    2011-01-01

    The aim of this paper is to document suitability of plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids. Surface-modified carbonyl iron particles were prepared via their exposure to 50% argon and 50% octafluorocyclobutane plasma. The X-ray photoelectron spectroscopy was used for analysis of chemical bonding states in the surface layer. Plasma-treated particles were adopted for a dispersed phase in magnetorheological (MR) fluids, and the MR behaviour was in...

  8. Selective transformation of carbonyl ligands to organic molecules: Progress report, 1 September 1986--31 August 1989

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, A.R.

    1989-04-18

    Studies on anionic phosphido alkyl and acetyl complexes Cp(CO)(PPh/sub 2/)Fe /minus/ R/sup /minus// (1) and In(CO)(PPh/sub 2/)Fe /minus/ R/sup /minus// (2) (R = CH/sub 3/ (a), COCH/sub 3/ (b); In = /eta//sup 5/-indenyl) and their neutral phosphine derivatives Cp(CO)(PPh/sub 2/H)Fe /minus/ R (3) and In(CO)(PPh/sub 2/H)Fe /minus/ R (4) are complete. Attempts to carbonylate 1a and 2a to 1b and 2b failed; also, 3a and 4a resist carbonylation. Reacting 1b with MeI affords a neutral PPh/sub 2/Me acetyl compound 5, whereas MeOSO/sub 2/CF/sub 3/ gives the Fischer carbene complex Cp(PPh/sub 2/)(CO) Fe = C(OMe)CH/sub 3/ (6). Carbene 6 isomerizes to 5 at room temperature. Reaction conditions have been optimized for tenerating vinylidene compounds In/sub 2/(CO)/sub 3/Fe/sub 2/ ..mu..-(C = CHR) from InFe(CO)/sub 2//sup /minus// and In(CO)/sub 2/Fe /minus/ CH/sub 2/R (R = H, Me, OMe). The bimetallic carbonylation procedure for converting Fp/sup /minus//(Li/sup +/, Na/sup +/, PPN/sup +/) and In(CO)/sub 2/Fe /minus/ CH/sub 3/ to InCp(CO)/sub 3/Fe/sub 2/(COCH/sub 3//sup /minus//) and then regioselectively to FpCOCH/sub 3/ (1 atm CO) has been optimized. Studies are finished on the diastereofacial selectivity observed during reduction of the alkoxycarbenes Cp(P(OR)/sub 3/)(CO)Fe = C(OCH/sub 3/)CH/sub 3//sup +/ (R = Me, Ph) with borohydride reagents R/sub 3/BH/sup /minus// (Li/sup +/, Na/sup +/, K/sup +/) and with (PPh/sub 3/CuH)/sub 6/. A survey of the Rh(I)-catalyzed hydrosilation of a variety of iron acyl complexes has been concluded.

  9. The activation of hydrogen by a high nuclearity metal cluster complex. The synthesis and structural characterization of Ru6(C0)15(μ-C0)2(μ3-H)2(μ4-S)

    International Nuclear Information System (INIS)

    Adams, R.D.; Babin, J.E.; Tasi, M.; Wolfe, T.A.

    1988-01-01

    This hexanuclear dihydride is prepared by reaction of hexaruthenium cluster with hydrogen (1 atm/80 0 C) for 15 minutes in 96% yield. It is characterized by IR, 1 H NMR and a single-crystal X-ray diffraction analysis. The structure was solved by direct methods and refined. There are two formula equivalents in the asymmetric crystal unit. Both molecules contain similar structures that consist of square-pyramidal clusters of five ruthenium atoms with a quadruply bridging sulfido ligand across the square base and a Ru (CO) 4 group across an edge of the square base. Both molecules possess two triply bridging hydride ligands that were located and refined and found to occupy adjacent triangular faces on the square pyramid. The complex is decomposed by C0. 11 refs

  10. Photodissociation spectroscopy of the Mg+-acetic acid complex

    Science.gov (United States)

    Abate, Yohannes; Kleiber, P. D.

    2006-11-01

    We have studied the structure and photodissociation of Mg+-acetic acid clusters. Ab initio calculations suggest four relatively strongly bound ground state isomers for the [MgC2H4O2]+ complex. These isomers include the cis and trans forms of the Mg+-acetic acid association complex with Mg+ bonded to the carbonyl O atom of acetic acid, the Mg+-acetic acid association complex with Mg+ bonded to the hydroxyl O atom of acetic acid, or to a Mg+-ethenediol association complex. Photodissociation through the Mg+-based 3p←3s absorption bands in the near UV leads to direct (nonreactive) and reactive dissociation products: Mg+, MgOH+, Mg(H2O )+, CH3CO+, and MgCH3+. At low energies the dominant reactive quenching pathway is through dehydration to Mg(H2O)+, but additional reaction channels involving C-H and C-C bond activation are also open at higher energies.

  11. Role of protein-bound carbonyl groups in the formation of advanced glycation endproducts.

    Science.gov (United States)

    Liggins, J; Furth, A J

    1997-08-22

    Several mechanisms have been postulated for the formation of advanced glycation endproducts (AGEs) from glycated proteins; they all feature protein-bound carbonyl intermediates. Using 2,4-dinitrophenylhydrazine (DNPH), we have detected these intermediates on bovine serum albumin, lysozyme and beta-lactoglobulin after in vitro glycation by glucose or fructose. Carbonyls were formed in parallel with AGE-fluorophores, via oxidative Maillard reactions. Neither Amadori nor Heyns products contributed to the DNPH reaction. Fluorophore and carbonyl yields were much enhanced in lipid-associated proteins, but both groups could also be detected in lipid-free proteins. When pre-glycated proteins were incubated in the absence of free sugar, carbonyl groups were rapidly lost in a first-order reaction, while fluorescence continued to develop beyond the 21 days of incubation. Another unexpected finding was that not all carbonyl groups were blocked by aminoguanidine, although there was complete inhibition of reactions leading to AGE-fluorescence. It is suggested that carbonyls acting as fluorophore precursors react readily with aminoguanidine, while others are resistant to this hydrazine, possibly because they are involved in ring closure. Factors influencing the relative rates of acyclisation and hydrazone formation are discussed, together with possible implications for antiglycation therapy.

  12. Carbonyl Emissions in E-cigarette Aerosol: A Systematic Review and Methodological Considerations

    Directory of Open Access Journals (Sweden)

    Konstantinos E. Farsalinos

    2018-01-01

    Full Text Available Carbonyl emissions from tobacco cigarettes represent a substantial health risk contributing to smoking-related morbidity and mortality. As expected, this is an important research topic for tobacco harm reduction products, in an attempt to compare the relative risk of these products compared to tobacco cigarettes. In this study, a systematic review of the literature available on PubMed was performed analyzing the studies evaluating carbonyl emissions from e-cigarettes. A total of 32 studies were identified and presented. We identified a large diversity of methodologies, with substantial discrepancies in puffing patterns, aerosol collection and analytical methods as well as reported units of measurements. Such discrepancies make comparisons difficult, and in some cases the accuracy of the findings cannot be determined. Importantly, control for the generation of dry puffs was not performed in the vast majority of studies, particularly in studies using variable power devices, which could result in testing conditions and reported carbonyl levels that have no clinical relevance or context. Some studies have been replicated, verifying the presence of dry puff conditions. Whenever realistic use conditions were ensured, carbonyl emissions from e-cigarettes were substantially lower than tobacco cigarette smoke, while newer generation (bottom-coil, cotton wick atomizers appeared to emit minimal levels of carbonyls with questionable clinical significance in terms of health risk. However, extremely high levels of carbonyl emissions were reported in some studies, and all these studies need to be replicated because of potentially important health implications.

  13. Predicting personal exposure to airborne carbonyls using residential measurements and time/activity data

    Science.gov (United States)

    Liu, Weili; Zhang, Junfeng (Jim); Korn, Leo R.; Zhang, Lin; Weisel, Clifford P.; Turpin, Barbara; Morandi, Maria; Stock, Tom; Colome, Steve

    As a part of the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study, 48 h integrated residential indoor, outdoor, and personal exposure concentrations of 10 carbonyls were simultaneously measured in 234 homes selected from three US cities using the Passive Aldehydes and Ketones Samplers (PAKS). In this paper, we examine the feasibility of using residential indoor concentrations to predict personal exposures to carbonyls. Based on paired t-tests, the means of indoor concentrations were not different from those of personal exposure concentrations for eight out of the 10 measured carbonyls, indicating indoor carbonyls concentrations, in general, well predicted the central tendency of personal exposure concentrations. In a linear regression model, indoor concentrations explained 47%, 55%, and 65% of personal exposure variance for formaldehyde, acetaldehyde, and hexaldehyde, respectively. The predictability of indoor concentrations on cross-individual variability in personal exposure for the other carbonyls was poorer, explainingexposure concentrations. It was found that activities related to driving a vehicle and performing yard work had significant impacts on personal exposures to a few carbonyls.

  14. COMPARATIVE STUDY OF EFFICACY OF FERROUS SULPHATE AND CARBONYL IRON IN ANEMIA OF ANTENATAL WOMEN

    Directory of Open Access Journals (Sweden)

    Radhika

    2015-03-01

    Full Text Available Iron deficiency anemia is the most common and important public health problem all over the world in the risk group of antenatal women. Research is going on to improve the iron status of the pregnant women with different forms of iron available. In this regard, Carbonyl Iron is showing promising results in improving the red cell mass with better compliance. 120 antenatal women were recruited in this study. The study comprised of 6weeks for each patient. They were given Carbonyl Iron 100 mg/day and FeS04 100gm/day . Before and after treatment all the baseline and specific investigations were one. Results were tabulated, comparison and significance were tested by unpaired student ’s’ test and their 'p' value was calculated. Results were shown graphically also. Carbonyl Iron showed improvement in hemoglobin, PCV and better than ferrous Sulphate (P <0.001. Incidence of side effects were less with Carbonyl Iron than Ferrous Sulphate, better compliance was seen with Carbonyl Iron. In conclusion, the present study s howed that Carbonyl Iron had better efficacy and safety in the management of Iron deficiency anemia in antenatal women than ferrous Sulphate

  15. Protein carbonylation associated to high-fat, high-sucrose diet and its metabolic effects.

    Science.gov (United States)

    Méndez, Lucía; Pazos, Manuel; Molinar-Toribio, Eunice; Sánchez-Martos, Vanesa; Gallardo, José M; Rosa Nogués, M; Torres, Josep L; Medina, Isabel

    2014-12-01

    The present research draws a map of the characteristic carbonylation of proteins in rats fed high-caloric diets with the aim of providing a new insight of the pathogenesis of metabolic diseases derived from the high consumption of fat and refined carbohydrates. Protein carbonylation was analyzed in plasma, liver and skeletal muscle of Sprague-Dawley rats fed a high-fat, high-sucrose (HFHS) diet by a proteomics approach based on carbonyl-specific fluorescence-labeling, gel electrophoresis and mass spectrometry. Oxidized proteins along with specific sites of oxidative damage were identified and discussed to illustrate the consequences of protein oxidation. The results indicated that long-term HFHS consumption increased protein oxidation in plasma and liver; meanwhile, protein carbonyls from skeletal muscle did not change. The increment of carbonylation by HFHS diet was singularly selective on specific target proteins: albumin from plasma and liver, and hepatic proteins such as mitochondrial carbamoyl-phosphate synthase (ammonia), mitochondrial aldehyde dehydrogenase, argininosuccinate synthetase, regucalcin, mitochondrial adenosine triphosphate synthase subunit beta, actin cytoplasmic 1 and mitochondrial glutamate dehydrogenase 1. The possible consequences that these specific protein carbonylations have on the excessive weight gain, insulin resistance and nonalcoholic fatty liver disease resulting from HFHS diet consumption are discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Line profile analyses of rhodium metal obtained by decomposition of rhodium carbonyl

    International Nuclear Information System (INIS)

    Chandra, D.; Mandalia, H.; Garner, M.L.; Blakely, M.K.; Lau, K.H.

    1995-01-01

    Metal carbonyls are important for chemical vapor deposition (CVD) of metals and alloys and formation of high surface area metallic particles which have potential applications as catalysts. Rhodium carbonyl [Rh 6 (CO) 16 ] produces high surface area metallic particles whose structure has been reported as monoclinic (I2/a) with lattice dimensions, a=17.00(±0.03)Angstrom, b=9.78(±0.02)Angstrom, c=17.53(±0.03)Angstrom and Β=121 degrees 45' ± 30' at room temperature. Generally, metal carbonyl crystals dissociate under vacuum as carbonyl gas and decompose to metallic crystals and carbon monoxide at higher temperatures. However, the behavior of rhodium carbonyl crystals is different; they decompose directly to metallic rhodium without the formation of rhodium carbonyl gas in vacuum. Several residual fine grains of rhodium metal are found after the decomposition in vacuum at relatively low temperatures. The metallic samples of rhodium were obtained from vapor pressure experiments using torsion Knudsen-effusion apparatus. X-ray diffraction analyses performed on these gains showed severely broadened Bragg reflections indicative of small particle size and/or lattice microgram. In this study, a comparison of lattice strains and domain sizes obtained by integral breadth and Fourier methods has been made. In addition a comparison of the lattice strains and domain sizes has been made between the Cauchy, Gaussian, Cauchy-Gaussian and Aqua integral breadth methods

  17. Characteristics of carbonyl compounds in public vehicles of Beijing city: Concentrations, sources, and personal exposures

    Science.gov (United States)

    Pang, Xiaobing; Mu, Yujing

    The characteristics of carbonyl compounds (carbonyls) including concentrations, major sources, and personal exposure were investigated for 29 vehicles including taxi, bus and subway in Beijing. It was found that the taxis (Xiali, TA) and buses (Huanghe, BA) fueled by gasoline with longer service years had the higher indoor carbonyl levels (178±42.7 and 188±31.6 μg m -3) while subways energized by electricity without exhaust and the jingwa buses (BB) driven in the suburb had the lower levels with total concentrations of 98.5±26.3 and 92.1±20.3 μg m -3, respectively. Outdoor carbonyls of taxi cars and buses were nearly at the same level with their total concentrations varying from 80 to 110 μg m -3. The level of outdoor subways carbonyls was equal with the ambient air levels. Exhaust leakage, indoor material emissions, photochemical formation, and infiltration of outdoor air were considered to be the major sources to in-vehicle carbonyls. Personal exposures and cancer risk to formaldehyde and acetaldehyde were calculated for professional bus and taxi drivers, respectively. Taxi drivers had the highest cancer risk with personal exposure to formaldehyde and acetaldehyde of 212 and 243 μg day -1, respectively. The public concern should pay considerable attention to professional drivers' health.

  18. Cluster evolution

    International Nuclear Information System (INIS)

    Schaeffer, R.

    1987-01-01

    The galaxy and cluster luminosity functions are constructed from a model of the mass distribution based on hierarchical clustering at an epoch where the matter distribution is non-linear. These luminosity functions are seen to reproduce the present distribution of objects as can be inferred from the observations. They can be used to deduce the redshift dependence of the cluster distribution and to extrapolate the observations towards the past. The predicted evolution of the cluster distribution is quite strong, although somewhat less rapid than predicted by the linear theory

  19. Clustering Game Behavior Data

    DEFF Research Database (Denmark)

    Bauckhage, C.; Drachen, Anders; Sifa, Rafet

    2015-01-01

    of the causes, the proliferation of behavioral data poses the problem of how to derive insights therefrom. Behavioral data sets can be large, time-dependent and high-dimensional. Clustering offers a way to explore such data and to discover patterns that can reduce the overall complexity of the data. Clustering...... and other techniques for player profiling and play style analysis have, therefore, become popular in the nascent field of game analytics. However, the proper use of clustering techniques requires expertise and an understanding of games is essential to evaluate results. With this paper, we address game data...... scientists and present a review and tutorial focusing on the application of clustering techniques to mine behavioral game data. Several algorithms are reviewed and examples of their application shown. Key topics such as feature normalization are discussed and open problems in the context of game analytics...

  20. Protein carbonylation, protein aggregation and neuronal cell death in a murine model of multiple sclerosis

    Science.gov (United States)

    Dasgupta, Anushka

    Many studies have suggested that oxidative stress plays an important role in the pathophysiology of both multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Yet, the mechanism by which oxidative stress leads to tissue damage in these disorders is unclear. Recent work from our laboratory has revealed that protein carbonylation, a major oxidative modification caused by severe and/or chronic oxidative stress conditions, is elevated in MS and EAE. Furthermore, protein carbonylation has been shown to alter protein structure leading to misfolding/aggregation. These findings prompted me to hypothesize that carbonylated proteins, formed as a consequence of oxidative stress and/or decreased proteasomal activity, promote protein aggregation to mediate neuronal apoptosis in vitro and in EAE. To test this novel hypothesis, I first characterized protein carbonylation, protein aggregation and apoptosis along the spinal cord during the course of myelin-oligodendrocyte glycoprotein (MOG)35-55 peptide-induced EAE in C57BL/6 mice [Chapter 2]. The results show that carbonylated proteins accumulate throughout the course of the disease, albeit by different mechanisms: increased oxidative stress in acute EAE and decreased proteasomal activity in chronic EAE. I discovered not only that there is a temporal correlation between protein carbonylation and apoptosis but also that carbonyl levels are significantly higher in apoptotic cells. A high number of juxta-nuclear and cytoplasmic protein aggregates containing the majority of the oxidized proteins are also present during the course of EAE, which seems to be due to reduced autophagy. In chapter 3, I show that when gluthathione levels are reduced to those in EAE spinal cord, both neuron-like PC12 (nPC12) cells and primary neuronal cultures accumulate carbonylated proteins and undergo cell death (both by necrosis and apoptosis). Immunocytochemical and biochemical studies also revealed a temporal

  1. Simultaneous detection of low and high molecular weight carbonylated compounds derived from lipid peroxidation by electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Milic, Ivana; Hoffmann, Ralf; Fedorova, Maria

    2013-01-02

    Reactive oxygen species (ROS) and other oxidative agents such as free radicals can oxidize polyunsaturated fatty acids (PUFA) as well as PUFA in lipids. The oxidation products can undergo consecutive reactions including oxidative cleavages to yield a chemically diverse group of products, such as lipid peroxidation products (LPP). Among them are aldehydes and ketones ("reactive carbonyls") that are strong electrophiles and thus can readily react with nucleophilic side chains of proteins, which can alter the protein structure, function, cellular distribution, and antigenicity. Here, we report a novel technique to specifically derivatize both low molecular and high molecular weight carbonylated LPP with 7-(diethylamino)coumarin-3-carbohydrazide (CHH) and analyze all compounds by electrospray ionization-mass spectrometry (ESI-MS) in positive ion mode. CHH-derivatized compounds were identified by specific neutral losses or fragment ions. The fragment ion spectra displayed additional signals that allowed unambiguous identification of the lipid, fatty acids, cleavage sites, and oxidative modifications. Oxidation of docosahexaenoic (DHA, 22:6), arachidonic (AA, 20:4), linoleic (LA, 18:2), and oleic acids (OA, 18:1) yielded 69 aliphatic carbonyls, whose structures were all deduced from the tandem mass spectra. When four phosphatidylcholine (PC) vesicles containing the aforementioned unsaturated fatty acids were oxidized, we were able to deduce the structures of 122 carbonylated compounds from the tandem mass spectra of a single shotgun analysis acquired within 15 min. The high sensitivity (LOD ∼ 1 nmol/L for 4-hydroxy-2-nonenal, HNE) and a linear range of more than 3 orders of magnitude (10 nmol/L to 10 μmol/L for HNE) will allow further studies on complex biological samples including plasma.

  2. Fast retrievals of tropospheric carbonyl sulfide with IASI

    Science.gov (United States)

    Vincent, R. Anthony; Dudhia, Anu

    2017-02-01

    Iterative retrievals of trace gases, such as carbonyl sulfide (OCS), from satellites can be exceedingly slow. The algorithm may even fail to keep pace with data acquisition such that analysis is limited to local events of special interest and short time spans. With this in mind, a linear retrieval scheme was developed to estimate total column amounts of OCS at a rate roughly 104 times faster than a typical iterative retrieval. This scheme incorporates two concepts not utilized in previously published linear estimates. First, all physical parameters affecting the signal are included in the state vector and accounted for jointly, rather than treated as effective noise. Second, the initialization point is determined from an ensemble of atmospheres based on comparing the model spectra to the observations, thus improving the linearity of the problem. All of the 2014 data from the Infrared Atmospheric Sounding Interferometer (IASI), instruments A and B, were analysed and showed spatial features of OCS total columns, including depletions over tropical rainforests, seasonal enhancements over the oceans, and distinct OCS features over land. Error due to assuming linearity was found to be on the order of 11 % globally for OCS. However, systematic errors from effects such as varying surface emissivity and extinction due to aerosols have yet to be robustly characterized. Comparisons to surface volume mixing ratio in situ samples taken by NOAA show seasonal correlations greater than 0.7 for five out of seven sites across the globe. Furthermore, this linear scheme was applied to OCS, but may also be used as a rapid estimator of any detectable trace gas using IASI or similar nadir-viewing instruments.

  3. Plasma protein carbonyl responses to anaerobic exercise in female cyclists

    Directory of Open Access Journals (Sweden)

    M.E Afzalpour

    2016-03-01

    Full Text Available Single bouts of aerobic exercise may leads to oxidative stress due to the use of oxygen for metabolism and the generation of reactive oxygen. In athletes, oxidative stress can lead to several deleterious performance effects, such as muscular oxidative damage, muscle soreness, loss of skeletal muscle force production and/or inflammation. However, little is known regarding the severity and duration of oxidative stress arising from intensive anaerobic modes of exercise in aerobically-trained athletes. The purpose of this study was to investigate the effect of a single bout of intensive anaerobic exercise on plasma protein carbonyl (PC in aerobically-trained women. Aerobically-trained, provincial female cyclists [n = 18, age: 24.2±2.7 years; stature: 163.6±4.6 cm; body mass: 53.4±4.2 kg] were randomly assigned into either a non-exercising control (CON; n = 9 or experimental (EXP; n = 9 group that underwent a 30-second anaerobic (Wingate cycle ergometer exercise session. Blood sampling took place before exercise, immediately after the exercise (IE, and 24 hours following the exercise (24HR bout. In the EXP, results indicated significant (P ≤ 0.05 differences in PC levels between the pre-test and IE (0.010±0.0124 to 0.0149±0.0420 mmol/milt; P = 0.010, and IE and 24HR (0.0149±0.0420 to 0.0111±0.0183 mmol/milt; P = 0.013. No significant differences were observed between pre-test and 24HR (0.010±0.0124 to 0.0111±0.0183 mmol/milt; P = 0.371. These results indicate that oxidative protein damage, as indicated by PC levels, rises immediately with the onset of anaerobic exercise, but returns to resting levels within 24 hours following exercise in aerobically-trained women.

  4. Surface Solvation of Halogen Anions in Water Clusters: An ab initio Molecular Dynamics Study of the Cl-(H.sub.2./sub.O).sub.6./sub. Complex

    Czech Academy of Sciences Publication Activity Database

    Tobias, D. J.; Jungwirth, Pavel; Parrinello, M.

    2001-01-01

    Roč. 114, č. 16 (2001), s. 7036-7044 ISSN 0021-9606 R&D Projects: GA MŠk LN00A032 Grant - others:NATO Science Program(XE) CLG-974459 Institutional research plan: CEZ:AV0Z4040901 Keywords : cluster * ab initio molecular dynamics * anionic solvation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.147, year: 2001

  5. Singlet Oxygen Production and Biological Activity of Hexanuclear Chalcocyanide Rhenium Cluster Complexes [{Re(6)Q(8)}(CN)(6)](4-) (Q = S, Se, Te)

    Czech Academy of Sciences Publication Activity Database

    Solovieva, A.O.; Kirakci, Kaplan; Ivanov, A.; Kubát, Pavel; Pozmogova, T.N.; Miroshnichenko, S.M.; Vorontsova, E.V.; Chechushkov, A.V.; Trifonova, K.E.; Fufaeva, M.S.; Kretov, E.I.; Mironov, Y.V.; Poveshchenko, A.F.; Lang, Kamil; Shestopalov, M.A.

    2017-01-01

    Roč. 56, č. 21 (2017), s. 13491-13499 ISSN 0020-1669 R&D Projects: GA ČR(CZ) GA16-15020S Institutional support: RVO:61388980 ; RVO:61388955 Keywords : photophysical properties * silica nanoparticles * molecular-oxygen * iodide cluster * luminescence Subject RIV: CA - Inorganic Chemistry; CF - Physical ; Theoretical Chemistry (UFCH-W) OBOR OECD: Inorganic and nuclear chemistry; Physical chemistry (UFCH-W) Impact factor: 4.857, year: 2016

  6. Bifunctional (cyclopentadienone)iron-tricarbonyl complexes: Synthesis, computational studies and application in reductive amination

    KAUST Repository

    Moulin, Solenne; Dentel, Hé lè ne; Pagnoux-Ozherelyeva, Anastassiya; Gaillard, Sylvain; Poater, Albert; Cavallo, Luigi; Lohier, Jean Franç ois; Renaud, Jean Luc

    2013-01-01

    . Festival of amination: Two series of modified Knölker's complexes were synthesised and applied in the reductive amination of various carbonyl derivatives with primary or secondary amines (see scheme, TIPS = triisopropylsilyl). For a mechanistic insight

  7. Nitrosylation of Nitric-Oxide-Sensing Regulatory Proteins Containing [4Fe-4S] Clusters Gives Rise to Multiple Iron-Nitrosyl Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Pauline N. [Department of Chemistry, University of California, Davis CA 95616 USA; Wang, Hongxin [Department of Chemistry, University of California, Davis CA 95616 USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Crack, Jason C. [Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park Norwich NR4 7TJ UK; Prior, Christopher [Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park Norwich NR4 7TJ UK; Hutchings, Matthew I. [School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ UK; Thomson, Andrew J. [Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park Norwich NR4 7TJ UK; Kamali, Saeed [University of Tennessee Space Institute, Tullahome TN 37388-9700 USA; Yoda, Yoshitaka [Research and Utilization Division, SPring-8/JASRI, 1-1-1 Kouto, Sayo Hyogo 679-5198 Japan; Zhao, Jiyong [Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Hu, Michael Y. [Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Alp, Ercan E. [Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Oganesyan, Vasily S. [Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park Norwich NR4 7TJ UK; Le Brun, Nick E. [Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park Norwich NR4 7TJ UK; Cramer, Stephen P. [Department of Chemistry, University of California, Davis CA 95616 USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA

    2016-10-25

    The reaction of protein-bound iron–sulfur (Fe-S) clusters with nitric oxide (NO) plays key roles in NO-mediated toxicity and signaling. Elucidation of the mechanism of the reaction of NO with DNA regulatory proteins that contain Fe-S clusters has been hampered by a lack of information about the nature of the iron-nitrosyl products formed. Herein, we report nuclear resonance vibrational spectroscopy (NRVS) and density functional theory (DFT) calculations that identify NO reaction products in WhiD and NsrR, regulatory proteins that use a [4Fe-4S] cluster to sense NO. This work reveals that nitrosylation yields multiple products structurally related to Roussin's Red Ester (RRE, [Fe2(NO)4(Cys)2]) and Roussin's Black Salt (RBS, [Fe4(NO)7S3]. In the latter case, the absence of 32S/34S shifts in the Fe-S region of the NRVS spectra suggest that a new species, Roussin's Black Ester (RBE), may be formed, in which one or more of the sulfide ligands is replaced by Cys thiolates.

  8. Molecular Engineering with Organic Carbonyl Electrode Materials for Advanced Stationary and Redox Flow Rechargeable Batteries.

    Science.gov (United States)

    Zhao, Qing; Zhu, Zhiqiang; Chen, Jun

    2017-12-01

    Organic carbonyl electrode materials that have the advantages of high capacity, low cost and being environmentally friendly, are regarded as powerful candidates for next-generation stationary and redox flow rechargeable batteries (RFBs). However, low carbonyl utilization, poor electronic conductivity and undesired dissolution in electrolyte are urgent issues to be solved. Here, we summarize a molecular engineering approach for tuning the capacity, working potential, concentration of active species, kinetics, and stability of stationary and redox flow batteries, which well resolves the problems of organic carbonyl electrode materials. As an example, in stationary batteries, 9,10-anthraquinone (AQ) with two carbonyls delivers a capacity of 257 mAh g -1 (2.27 V vs Li + /Li), while increasing the number of carbonyls to four with the formation of 5,7,12,14-pentacenetetrone results in a higher capacity of 317 mAh g -1 (2.60 V vs Li + /Li). In RFBs, AQ, which is less soluble in aqueous electrolyte, reaches 1 M by grafting -SO 3 H with the formation of 9,10-anthraquinone-2,7-disulphonic acid, resulting in a power density exceeding 0.6 W cm -2 with long cycling life. Therefore, through regulating substituent groups, conjugated structures, Coulomb interactions, and the molecular weight, the electrochemical performance of carbonyl electrode materials can be rationally optimized. This review offers fundamental principles and insight into designing advanced carbonyl materials for the electrodes of next-generation rechargeable batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Proteomic identification of carbonylated proteins in F344 rat hippocampus after 1-bromopropane exposure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhenlie [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan); Department of Toxicology, Guangdong Prevention and Treatment Center for Occupational Diseases, Guangzhou 510‐300 (China); Ichihara, Sahoko [Graduate School of Regional Innovation Studies, Mie University, Tsu 514‐8507 (Japan); Oikawa, Shinji [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514‐8507 (Japan); Chang, Jie; Zhang, Lingyi; Subramanian, Kaviarasan; Mohideen, Sahabudeen Sheik [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan); Ichihara, Gaku, E-mail: gak@med.nagoya-u.ac.jp [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan)

    2012-08-15

    1-Bromopropane (1-BP) is neurotoxic in both experimental animals and humans. Previous proteomic analysis of rat hippocampus implicated alteration of protein expression in oxidative stress, suggesting that oxidative stress plays a role in 1-BP-induced neurotoxicity. To understand this role at the protein level, we exposed male F344 rats to 1-BP at 0, 400, or 1000 ppm for 8 h/day for 1 week or 4 weeks by inhalation and quantitated changes in hippocampal protein carbonyl using a protein carbonyl assay, two-dimensional gel electrophoresis (2-DE), immunoblotting, and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-TOF/MS). Hippocampal reactive oxygen species and protein carbonyl were significantly increased, demonstrating 1-BP-associated induction of oxidative stress and protein damage. MALDI-TOF-TOF/MS identified 10 individual proteins with increased carbonyl modification (p < 0.05; fold-change ≥ 1.5). The identified proteins were involved in diverse biological processes including glycolysis, ATP production, tyrosine catabolism, GTP binding, guanine degradation, and neuronal metabolism of dopamine. Hippocampal triosephosphate isomerase (TPI) activity was significantly reduced and negatively correlated with TPI carbonylation (p < 0.001; r = 0.83). Advanced glycation end-product (AGE) levels were significantly elevated both in the hippocampus and plasma, and hippocampal AGEs correlated negatively with TPI activity (p < 0.001; r = 0.71). In conclusion, 1-BP-induced neurotoxicity in the rat hippocampus seems to involve oxidative damage of cellular proteins, decreased TPI activity, and elevated AGEs. -- Highlights: ► 1-BP increases hippocampal ROS levels and hippocampal and plasma protein carbonyls. ► 1-BP increases TPI carbonylation and decreases TPI activity in the hippocampus. ► 1-BP increases hippocampal and plasma AGE levels.

  10. Identifying Clusters of Complex Urban–Rural Issues as Part of Policy Making Process Using a Network Analysis Approach: A Case Study in Bahía de Los Ángeles, Mexico

    Directory of Open Access Journals (Sweden)

    Javier Sandoval

    2017-06-01

    Full Text Available Improving human settlements diagnosis is a key factor in effective urban planning and the design of efficient policy making. In this paper, we illustrate how network theory concepts can be applied to reveal the topological structure of functional relationships in a network of heterogeneous urban–rural issues. This mapping is done using clustering algorithms and centrality value techniques. By analyzing emergent groups of urban–rural related issues, our methodology was applied to a rural community, considering in this exercise environmental matters and real estate interests as a way to better understand the structure of salient issues in the context of its urban development program design. Results show clusters that arrange themselves not by an obvious similarity in their constituent components, but by relations observed in urban–rural settings that hint on the issues that the urban development program must focus. Due to its complex nature, the classification of these emerging clusters and how they must be treated in traditional planning instruments is a new challenge that this novel methodology reveals.

  11. Clustering Dycom

    KAUST Repository

    Minku, Leandro L.

    2017-10-06

    Background: Software Effort Estimation (SEE) can be formulated as an online learning problem, where new projects are completed over time and may become available for training. In this scenario, a Cross-Company (CC) SEE approach called Dycom can drastically reduce the number of Within-Company (WC) projects needed for training, saving the high cost of collecting such training projects. However, Dycom relies on splitting CC projects into different subsets in order to create its CC models. Such splitting can have a significant impact on Dycom\\'s predictive performance. Aims: This paper investigates whether clustering methods can be used to help finding good CC splits for Dycom. Method: Dycom is extended to use clustering methods for creating the CC subsets. Three different clustering methods are investigated, namely Hierarchical Clustering, K-Means, and Expectation-Maximisation. Clustering Dycom is compared against the original Dycom with CC subsets of different sizes, based on four SEE databases. A baseline WC model is also included in the analysis. Results: Clustering Dycom with K-Means can potentially help to split the CC projects, managing to achieve similar or better predictive performance than Dycom. However, K-Means still requires the number of CC subsets to be pre-defined, and a poor choice can negatively affect predictive performance. EM enables Dycom to automatically set the number of CC subsets while still maintaining or improving predictive performance with respect to the baseline WC model. Clustering Dycom with Hierarchical Clustering did not offer significant advantage in terms of predictive performance. Conclusion: Clustering methods can be an effective way to automatically generate Dycom\\'s CC subsets.

  12. Clustering analysis

    International Nuclear Information System (INIS)

    Romli

    1997-01-01

    Cluster analysis is the name of group of multivariate techniques whose principal purpose is to distinguish similar entities from the characteristics they process.To study this analysis, there are several algorithms that can be used. Therefore, this topic focuses to discuss the algorithms, such as, similarity measures, and hierarchical clustering which includes single linkage, complete linkage and average linkage method. also, non-hierarchical clustering method, which is popular name K -mean method ' will be discussed. Finally, this paper will be described the advantages and disadvantages of every methods

  13. Cluster analysis

    CERN Document Server

    Everitt, Brian S; Leese, Morven; Stahl, Daniel

    2011-01-01

    Cluster analysis comprises a range of methods for classifying multivariate data into subgroups. By organizing multivariate data into such subgroups, clustering can help reveal the characteristics of any structure or patterns present. These techniques have proven useful in a wide range of areas such as medicine, psychology, market research and bioinformatics.This fifth edition of the highly successful Cluster Analysis includes coverage of the latest developments in the field and a new chapter dealing with finite mixture models for structured data.Real life examples are used throughout to demons

  14. Cluster editing

    DEFF Research Database (Denmark)

    Böcker, S.; Baumbach, Jan

    2013-01-01

    . The problem has been the inspiration for numerous algorithms in bioinformatics, aiming at clustering entities such as genes, proteins, phenotypes, or patients. In this paper, we review exact and heuristic methods that have been proposed for the Cluster Editing problem, and also applications......The Cluster Editing problem asks to transform a graph into a disjoint union of cliques using a minimum number of edge modifications. Although the problem has been proven NP-complete several times, it has nevertheless attracted much research both from the theoretical and the applied side...

  15. CytoCluster: A Cytoscape Plugin for Cluster Analysis and Visualization of Biological Networks.

    Science.gov (United States)

    Li, Min; Li, Dongyan; Tang, Yu; Wu, Fangxiang; Wang, Jianxin

    2017-08-31

    Nowadays, cluster analysis of biological networks has become one of the most important approaches to identifying functional modules as well as predicting protein complexes and network biomarkers. Furthermore, the visualization of clustering results is crucial to display the structure of biological networks. Here we present CytoCluster, a cytoscape plugin integrating six clustering algorithms, HC-PIN (Hierarchical Clustering algorithm in Protein Interaction Networks), OH-PIN (identifying Overlapping and Hierarchical modules in Protein Interaction Networks), IPCA (Identifying Protein Complex Algorithm), ClusterONE (Clustering with Overlapping Neighborhood Expansion), DCU (Detecting Complexes based on Uncertain graph model), IPC-MCE (Identifying Protein Complexes based on Maximal Complex Extension), and BinGO (the Biological networks Gene Ontology) function. Users can select different clustering algorithms according to their requirements. The main function of these six clustering algorithms is to detect protein complexes or functional modules. In addition, BinGO is used to determine which Gene Ontology (GO) categories are statistically overrepresented in a set of genes or a subgraph of a biological network. CytoCluster can be easily expanded, so that more clustering algorithms and functions can be added to this plugin. Since it was created in July 2013, CytoCluster has been downloaded more than 9700 times in the Cytoscape App store and has already been applied to the analysis of different biological networks. CytoCluster is available from http://apps.cytoscape.org/apps/cytocluster.

  16. A New Polynuclear Coordination Type for (Salicylaldoxime)copper(II) Complexes: Structure and Magnetic Properties of an (Oxime)Cu6 Cluster

    DEFF Research Database (Denmark)

    Wenzel, Marco; Forgan, Ross S.; Faure, Anaëlle

    2009-01-01

    A previously unseen coordination mode is reported for (salicylaldoxime)copper complexes utilising a linked zwitterionic NO22- donor set. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)...

  17. A complex of Cas proteins 5, 6, and 7 is required for the biogenesis and stability of clustered regularly interspaced short palindromic repeats (crispr)-derived rnas (crrnas) in Haloferax volcanii.

    Science.gov (United States)

    Brendel, Jutta; Stoll, Britta; Lange, Sita J; Sharma, Kundan; Lenz, Christof; Stachler, Aris-Edda; Maier, Lisa-Katharina; Richter, Hagen; Nickel, Lisa; Schmitz, Ruth A; Randau, Lennart; Allers, Thorsten; Urlaub, Henning; Backofen, Rolf; Marchfelder, Anita

    2014-03-07

    The clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR-Cas) system is a prokaryotic defense mechanism against foreign genetic elements. A plethora of CRISPR-Cas versions exist, with more than 40 different Cas protein families and several different molecular approaches to fight the invading DNA. One of the key players in the system is the CRISPR-derived RNA (crRNA), which directs the invader-degrading Cas protein complex to the invader. The CRISPR-Cas types I and III use the Cas6 protein to generate mature crRNAs. Here, we show that the Cas6 protein is necessary for crRNA production but that additional Cas proteins that form a CRISPR-associated complex for antiviral defense (Cascade)-like complex are needed for crRNA stability in the CRISPR-Cas type I-B system in Haloferax volcanii in vivo. Deletion of the cas6 gene results in the loss of mature crRNAs and interference. However, cells that have the complete cas gene cluster (cas1-8b) removed and are transformed with the cas6 gene are not able to produce and stably maintain mature crRNAs. crRNA production and stability is rescued only if cas5, -6, and -7 are present. Mutational analysis of the cas6 gene reveals three amino acids (His-41, Gly-256, and Gly-258) that are essential for pre-crRNA cleavage, whereas the mutation of two amino acids (Ser-115 and Ser-224) leads to an increase of crRNA amounts. This is the first systematic in vivo analysis of Cas6 protein variants. In addition, we show that the H. volcanii I-B system contains a Cascade-like complex with a Cas7, Cas5, and Cas6 core that protects the crRNA.

  18. A Complex of Cas Proteins 5, 6, and 7 Is Required for the Biogenesis and Stability of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-derived RNAs (crRNAs) in Haloferax volcanii*

    Science.gov (United States)

    Brendel, Jutta; Stoll, Britta; Lange, Sita J.; Sharma, Kundan; Lenz, Christof; Stachler, Aris-Edda; Maier, Lisa-Katharina; Richter, Hagen; Nickel, Lisa; Schmitz, Ruth A.; Randau, Lennart; Allers, Thorsten; Urlaub, Henning; Backofen, Rolf; Marchfelder, Anita

    2014-01-01

    The clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR-Cas) system is a prokaryotic defense mechanism against foreign genetic elements. A plethora of CRISPR-Cas versions exist, with more than 40 different Cas protein families and several different molecular approaches to fight the invading DNA. One of the key players in the system is the CRISPR-derived RNA (crRNA), which directs the invader-degrading Cas protein complex to the invader. The CRISPR-Cas types I and III use the Cas6 protein to generate mature crRNAs. Here, we show that the Cas6 protein is necessary for crRNA production but that additional Cas proteins that form a CRISPR-associated complex for antiviral defense (Cascade)-like complex are needed for crRNA stability in the CRISPR-Cas type I-B system in Haloferax volcanii in vivo. Deletion of the cas6 gene results in the loss of mature crRNAs and interference. However, cells that have the complete cas gene cluster (cas1–8b) removed and are transformed with the cas6 gene are not able to produce and stably maintain mature crRNAs. crRNA production and stability is rescued only if cas5, -6, and -7 are present. Mutational analysis of the cas6 gene reveals three amino acids (His-41, Gly-256, and Gly-258) that are essential for pre-crRNA cleavage, whereas the mutation of two amino acids (Ser-115 and Ser-224) leads to an increase of crRNA amounts. This is the first systematic in vivo analysis of Cas6 protein variants. In addition, we show that the H. volcanii I-B system contains a Cascade-like complex with a Cas7, Cas5, and Cas6 core that protects the crRNA. PMID:24459147

  19. K-means cluster analysis of rehabilitation service users in the Home Health Care System of Ontario: examining the heterogeneity of a complex geriatric population.

    Science.gov (United States)

    Armstrong, Joshua J; Zhu, Mu; Hirdes, John P; Stolee, Paul

    2012-12-01

    To examine the heterogeneity of home care clients who use rehabilitation services by using the K-means algorithm to identify previously unknown patterns of clinical characteristics. Observational study of secondary data. Home care system. Assessment information was collected on 150,253 home care clients using the provincially mandated Resident Assessment Instrument-Home Care (RAI-HC) data system. Not applicable. Assessment information from every long-stay (>60 d) home care client that entered the home care system between 2005 and 2008 and used rehabilitation services within 3 months of their initial assessment was analyzed. The K-means clustering algorithm was applied using 37 variables from the RAI-HC assessment. The K-means cluster analysis resulted in the identification of 7 relatively homogeneous subgroups that differed on characteristics such as age, sex, cognition, and functional impairment. Client profiles were created to illustrate the diversity of this geriatric population. The K-means algorithm provided a useful way to segment a heterogeneous rehabilitation client population into more homogeneous subgroups. This analysis provides an enhanced understanding of client characteristics and needs, and could enable more appropriate targeting of rehabilitation services for home care clients. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  20. Occupational Clusters.

    Science.gov (United States)

    Pottawattamie County School System, Council Bluffs, IA.

    The 15 occupational clusters (transportation, fine arts and humanities, communications and media, personal service occupations, construction, hospitality and recreation, health occupations, marine science occupations, consumer and homemaking-related occupations, agribusiness and natural resources, environment, public service, business and office…

  1. Fuzzy Clustering

    DEFF Research Database (Denmark)

    Berks, G.; Keyserlingk, Diedrich Graf von; Jantzen, Jan

    2000-01-01

    A symptom is a condition indicating the presence of a disease, especially, when regarded as an aid in diagnosis.Symptoms are the smallest units indicating the existence of a disease. A syndrome on the other hand is an aggregate, set or cluster of concurrent symptoms which together indicate...... and clustering are the basic concerns in medicine. Classification depends on definitions of the classes and their required degree of participant of the elements in the cases' symptoms. In medicine imprecise conditions are the rule and therefore fuzzy methods are much more suitable than crisp ones. Fuzzy c......-mean clustering is an easy and well improved tool, which has been applied in many medical fields. We used c-mean fuzzy clustering after feature extraction from an aphasia database. Factor analysis was applied on a correlation matrix of 26 symptoms of language disorders and led to five factors. The factors...

  2. Enhanced microwave absorption in ZnO/carbonyl iron nano-composites by coating dielectric material

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Chang [School of Physics and Material Science, Anhui University, Hefei 230036 (China); Key Laboratory of Opto-electronic Information Acquisition and Manipulation Ministry of Education, Anhui University, Hefei 230039 (China); Fang Qingqing, E-mail: physfangqq@126.com [School of Physics and Material Science, Anhui University, Hefei 230036 (China) and Key Laboratory of Opto-electronic Information Acquisition and Manipulation Ministry of Education, Anhui University, Hefei 230039 (China); Yan Fangliang; Wang Weina; Wu Keyue; Liu Yanmei; Lv Qingrong; Zhang Hanming; Zhang Qiping; Li Jinguang; Ding Qiongqiong [School of Physics and Material Science, Anhui University, Hefei 230036 (China); Key Laboratory of Opto-electronic Information Acquisition and Manipulation Ministry of Education, Anhui University, Hefei 230039 (China)

    2012-05-15

    The microwave absorption properties of zinc oxide/carbonyl iron composite nanoparticles fabricated by high energy ball milling were studied at 0-20 GHz. Experiments showed that ZnO as a kind of dielectric material coating carbonyl iron particles made the bandwidth of reflection loss (RL)<-5 dB expanding to the low frequency, and enhanced absorption effect obviously. For a 3 mm thickness absorber of ZnO/carbonyl iron after 30 h milling, the values of RL<-5 dB and RL<-8 dB were obtained in the frequency range from 7.0 GHz to 17.8 GHz and from 9.8 dB to 14.9 dB, respectively, and its strongest RL peak was -29.34 dB at 13.59 GHz. The magnetic loss of carbonyl iron particles and the dielectric loss of ZnO particles were the main mechanisms of microwave absorption for the composites. - Highlights: Black-Right-Pointing-Pointer We fabricated zinc oxide/carbonyl iron composites by high energy ball milling. Black-Right-Pointing-Pointer ZnO dielectric property increased absorption effect and absorption bandwidth. Black-Right-Pointing-Pointer Absorbing frequence of composites is expanding to low frequency direction. Black-Right-Pointing-Pointer The craft of high energy ball milling is easy to realize commerce production.

  3. Enhanced microwave absorption in ZnO/carbonyl iron nano-composites by coating dielectric material

    International Nuclear Information System (INIS)

    Zhou Chang; Fang Qingqing; Yan Fangliang; Wang Weina; Wu Keyue; Liu Yanmei; Lv Qingrong; Zhang Hanming; Zhang Qiping; Li Jinguang; Ding Qiongqiong

    2012-01-01

    The microwave absorption properties of zinc oxide/carbonyl iron composite nanoparticles fabricated by high energy ball milling were studied at 0–20 GHz. Experiments showed that ZnO as a kind of dielectric material coating carbonyl iron particles made the bandwidth of reflection loss (RL)<−5 dB expanding to the low frequency, and enhanced absorption effect obviously. For a 3 mm thickness absorber of ZnO/carbonyl iron after 30 h milling, the values of RL<−5 dB and RL<−8 dB were obtained in the frequency range from 7.0 GHz to 17.8 GHz and from 9.8 dB to 14.9 dB, respectively, and its strongest RL peak was −29.34 dB at 13.59 GHz. The magnetic loss of carbonyl iron particles and the dielectric loss of ZnO particles were the main mechanisms of microwave absorption for the composites. - Highlights: ► We fabricated zinc oxide/carbonyl iron composites by high energy ball milling. ► ZnO dielectric property increased absorption effect and absorption bandwidth. ► Absorbing frequence of composites is expanding to low frequency direction. ► The craft of high energy ball milling is easy to realize commerce production.

  4. Catalytic reactions of synthesis gas. Part 2. Methanol carbonylation and homologation

    Energy Technology Data Exchange (ETDEWEB)

    Niemelae, M.

    1993-01-01

    The aim of the review is to evaluate the applicability of methanol hydrocarbonylation as a second test reaction to study the nondissociative activation of CO by heterogeneous rhodium and cobalt catalysts. The main emphasis in methanol (hydro)carbonylation chemistry has been on homogeneous reactions. These systems have been seen advantageous in selectivity, activity and ease of modification. The heterogenization attempts have been carried out to obtain easier separation of the catalyst and the product. The activity of cobalt, rhodium and other metals supported on different materials have been studied in heterogeneous methanol (hydro)carbonylation. The observed activities have been considerably influenced by the support. The most effective catalyst support has been activated carbon. Good carbonylation activities and selectivities have also been observed in conjunction with zeolite supports. The literature study indicates that the typical experimental conditions of methanol (hydro)carbonylation do not exceed the constructional and operational limits of the available reactor system, i.e. 500 C and 50 bar. The reaction is suitable for testing Co and Rh precursors, since both cobalt and rhodium compounds have shown carbonylation activity.

  5. Enhanced antioxidation and microwave absorbing properties of SiO2-coated flaky carbonyl iron particles

    Science.gov (United States)

    Zhou, Yingying; Xie, Hui; Zhou, Wancheng; Ren, Zhaowen

    2018-01-01

    SiO2 was successfully coated on the surface of flaky carbonyl iron particles using a chemical bath deposition method in the presence of 3-aminopropyl triethoxysilane (APTES). The morphologies, composition, valence states of elements, as well as antioxidation and electromagnetic properties of the samples were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) and microwave network analyzer. TG curve shows the obvious weight gain of carbonyl iron was deferred to 360 °C after SiO2-coated, which can be ascribed to the exits of SiO2 overlayer. Compared with the raw carbonyl iron, SiO2-coated sample shows good wave absorption performance due to its impedance matching. The electromagnetic properties of raw and SiO2-coated carbonyl iron particles were characterized in X band before and after heat treatment at 250 °C for 10 h. It was established that SiO2-coated carbonyl iron demonstrate good thermal stability, indicating SiO2-coating is useful in the usage of microwave absorbers operating at temperature up to 250 °C.

  6. Proteomic evaluation of myofibrillar carbonylation in chilled fish mince and its inhibition by catechin.

    Science.gov (United States)

    Pazos, Manuel; Maestre, Rodrigo; Gallardo, José M; Medina, Isabel

    2013-01-01

    The present study investigates the susceptibility of individual myofibrillar proteins from mackerel (Scomber scombrus) mince to undergo carbonylation reactions during chilled storage, and the antioxidant capacity of (+)-catechin to prevent oxidative processes of proteins. The carbonylation of each particular protein was quantified by combining the labelling of protein carbonyls by fluorescein-5-thiosemicarbazide (FTSC) with 1-D or 2-D gel electrophoresis. Alpha skeletal actin, glycogen phosphorylase, unnamed protein product (UNP) similar to enolase, pyruvate kinase, isoforms of creatine kinase, aldolase A and an isoform of glyceraldehyde 3-phosphate dehydrogenase (G3PDH) showed elevated oxidation in chilled non-supplemented mince. Myosin heavy chain (MHC) was not carbonylated in chilled muscle, but an extensive MHC degradation was observed in those samples. The supplementation of catechin reduced protein oxidation and lipid oxidation in a concentration-dependent manner: control>25>100≈200ppm. Therefore, the highest catechin concentrations (100 and 200ppm) exhibited the strongest antioxidant activity. Catechin (200ppm) reduced significantly carbonylation of protein spots identified as glycogen phosphorylase, pyruvate kinase muscle isozyme, isoforms of creatine kinase. Conversely, catechin was ineffective to inhibit the oxidation of actin and UNP similar to enolase. These results draw attention to the inefficiency of catechin to prevent actin oxidation, in contrast to the extremely high efficiency of catechin in inhibiting oxidation of lipids and other proteins. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Cluster generator

    Science.gov (United States)

    Donchev, Todor I [Urbana, IL; Petrov, Ivan G [Champaign, IL

    2011-05-31

    Described herein is an apparatus and a method for producing atom clusters based on a gas discharge within a hollow cathode. The hollow cathode includes one or more walls. The one or more walls define a sputtering chamber within the hollow cathode and include a material to be sputtered. A hollow anode is positioned at an end of the sputtering chamber, and atom clusters are formed when a gas discharge is generated between the hollow anode and the hollow cathode.

  8. Cluster Bulleticity

    OpenAIRE

    Massey, Richard; Kitching, Thomas; Nagai, Daisuke

    2010-01-01

    The unique properties of dark matter are revealed during collisions between clusters of galaxies, such as the bullet cluster (1E 0657−56) and baby bullet (MACS J0025−12). These systems provide evidence for an additional, invisible mass in the separation between the distributions of their total mass, measured via gravitational lensing, and their ordinary ‘baryonic’ matter, measured via its X-ray emission. Unfortunately, the information available from these systems is limited by their rarity. C...

  9. Cluster headache

    OpenAIRE

    Leroux, Elizabeth; Ducros, Anne

    2008-01-01

    Abstract Cluster headache (CH) is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes) of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye). It affects young adults, predominantly males. Prevalence is estimated at 0.5–1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name) in bouts that can occur ...

  10. Cluster Based Text Classification Model

    DEFF Research Database (Denmark)

    Nizamani, Sarwat; Memon, Nasrullah; Wiil, Uffe Kock

    2011-01-01

    We propose a cluster based classification model for suspicious email detection and other text classification tasks. The text classification tasks comprise many training examples that require a complex classification model. Using clusters for classification makes the model simpler and increases...... the accuracy at the same time. The test example is classified using simpler and smaller model. The training examples in a particular cluster share the common vocabulary. At the time of clustering, we do not take into account the labels of the training examples. After the clusters have been created......, the classifier is trained on each cluster having reduced dimensionality and less number of examples. The experimental results show that the proposed model outperforms the existing classification models for the task of suspicious email detection and topic categorization on the Reuters-21578 and 20 Newsgroups...

  11. Electromagnetic absorbing property of the flaky carbonyl iron particles by chemical corrosion process

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Dianliang, E-mail: 272895980@qq.com [College of Aeronautical Engineering, Jilin Institute of Chemical Technology, Jilin 132022 (China); Liu, Ting; Zhou, Li [College of Aeronautical Engineering, Jilin Institute of Chemical Technology, Jilin 132022 (China); Xu, Yonggang [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai 200438 (China)

    2016-12-01

    The flaky carbonyl iron particles (CIPs) were prepared using a milling process at the first step, then the chemical corrosion process was done to optimize the particle shape. The particle morphology was characterized by the scanning electron microscopy, the static magnetic property was evaluated on a vibrating sample magnetometer and X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The complex permittivity and permeability were measured using a vector network analyzer in the frequency range of 2–18 GHz and the reflection loss (RL) was calculated. The results showed that the saturation magnetization value of the CIPs decreased as the CIPs was corroded to the small flakes in chemical corrosion process. The diffraction peaks of the single α-Fe existed in the XRD pattern of CIPs, and the characteristic peaks was more obvious and the intensity of the diffraction pattern was lower by corrosion. The permittivity and the permeability of the corroded milling CIPs was a little larger than the milling CIPs, it was due to the larger aspect ratio based on the fitting calculation process. At thickness 0.6 mm and 0.8 mm, the corroded milling CIPs composite had the better absorbing property than the other two samples. The frequency band (RL<−5 dB) could be widened to 8.96–18 GHz at 0.6 mm and 5.92–18 GHz at 0.8 mm, and RL less than −8 dB began to exist in 8.96–14.72 GHz at 0.8 mm. - Graphical abstract: The property of absorber using corrosion process could be enhanced. - Highlights: • The chemical corrosion process was done to optimize the particle shape. • The permittivity and permeability of corroded milling CIPs increased. • The aspect ratio of flaky CIPs increased in the corrosion process. • The corroded milling CIPs composite had the better absorbing property.

  12. Influence of the Dielectric Medium on the Carbonyl Infrared Absorption Peak of Acetylferrocene

    Directory of Open Access Journals (Sweden)

    F. López-Linares

    2005-02-01

    Full Text Available The solvent effect on the position of the carbonyl vibrational stretching ofacetylferrocene in aprotic media was studied in this work. The solvent-induced shifts in thisorganometallic compound were interpreted in terms of the alternative reaction field model(SCRF-MO proposed by Kolling. In contrast to the established trends for carbonyl groupsin organic systems, the results suggest that the continuum models for the reaction field arenot adequate and that the influence of dipolarity-polarizability described by aninhomogeneous coupling function θ (ε L(n 2 that assumes optical dielectric saturation isresponsible for the carbonyl band shift and, there is empirical evidence that the effect offield-induced intermolecular interaction on band shift, interpreted in terms of the van derWaals forces from the solvent, have a important contribution to this phenomena.

  13. Coal and biomass-based chemicals via carbonylation, hydroformylation and homologation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sunavala, P.D.; Raghunath, B.

    The paper emphasizes the importance of carbonylation, hydroformylation and homologation reactions in the manufacture of organic chemicals (such as acetic acid, acetic anhydride, cellulose acetate, vinyl acetate monomer, aliphatic amines, isocyanates, methanol, ethanol, n-butanol, ethylene glycol, acrylic acid, etc.) from coal and biomass feedstocks. Topics covered are: synthesis of acetic acid; manufacture of acetic anhydride; synthesis of vinyl acetate monomer by carbonylation; synthesis of aliphatic amines by hydroformylation; synthesis of organic diisocyanates; ethanol synthesis by homologation of methanol; synthesis of ethylene glycol via hydroformylation of formaldehyde; synthesis of n- butanol and n-butyraldehyde by propylene formylation; synthesis of acrylic acid; homologation reaction of carboxylic acid esters with ruthenium catalysts; and synthesis of phenyl isocyanate from nitrobenzene by reductive carbonylation. 26 refs.

  14. Effect of carbonyl iron particles composition on the physical characteristics of MR grease

    Energy Technology Data Exchange (ETDEWEB)

    Mohamad, Norzilawati, E-mail: mnorzilawati@gmail.com; Mazlan, Saiful Amri, E-mail: amri.kl@utm.my [Vehicle System Engineering, Malaysia – Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra (Jalan Semarak), Kuala Lumpur, 54000 (Malaysia); Ubaidillah, E-mail: ubaidillah@uns.ac.id [Vehicle System Engineering, Malaysia – Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra (Jalan Semarak), Kuala Lumpur, 54000 (Malaysia); Mechanical Engineering Department, Faculty of Engineering, Universitas Sebelas Maret, Jl. Ir. Sutami 36A, Kentingan, Surakarta, 57126, Central Java, Surakarta (Indonesia)

    2016-03-29

    Magnetorheological (MR) grease is an extension of the study of magnetorheological materials. The MR grease can help to reduce the particles sedimentation problem occurred in the MR fluids. Within this study, an effort has been taken to investigate the effect of different weight compositions of carbonyl iron particles on the physical and chemical characteristics of the MR grease under off-state condition (no magnetic field). The MR grease is prepared by mixing carbonyl iron particles having a size range of 1 to 10 µm with commercial NPC Highrex HD-3 grease. Characterizations of MR grease are investigated using Vibrating Sample Magnetometer (VSM), Environmental Scanning Electron Microscopy (ESEM), Differential Scanning Calorimeter (DSC) and rheometer. The dependency of carbonyl iron particles weight towards the magnetic properties of MR grease and other characterizations are investigated.

  15. Exotic cluster structures on

    CERN Document Server

    Gekhtman, M; Vainshtein, A

    2017-01-01

    This is the second paper in the series of papers dedicated to the study of natural cluster structures in the rings of regular functions on simple complex Lie groups and Poisson-Lie structures compatible with these cluster structures. According to our main conjecture, each class in the Belavin-Drinfeld classification of Poisson-Lie structures on \\mathcal{G} corresponds to a cluster structure in \\mathcal{O}(\\mathcal{G}). The authors have shown before that this conjecture holds for any \\mathcal{G} in the case of the standard Poisson-Lie structure and for all Belavin-Drinfeld classes in SL_n, n<5. In this paper the authors establish it for the Cremmer-Gervais Poisson-Lie structure on SL_n, which is the least similar to the standard one.

  16. a Moessbauer Effect and Fenske-Hall Molecular Orbital Study of the Electronic Properties of Organoiron Clusters.

    Science.gov (United States)

    Buhl, Margaret Linn

    The electronic properties of trinuclear iron, tetranuclear iron butterfly, iron-cobalt, and iron-copper clusters have been studied experimentally at 78K by the Mossbauer effect and theoretically by Fenske-Hall molecular orbital calculations. The Mossbauer effect isomer shift is very sensitive to the differences in the iron s-electron densities in these clusters and, as expected, decreases as the sum of the iron 4s Mulliken population and the Clementi and Raimondi effective nuclear charge increases. The molecular orbital wave functions and the Mulliken atomic charges are used to calculate the electric field gradient at the metal nuclei and the iron Mossbauer effect quadrupole splittings. The valence contribution was found to be the major component of the electric field gradient in all the clusters studied. In general the calculated value of Delta E_ {Q} is larger than the observed value, as a result of neglect of the valence Sternheimer factor, R. The metal charge depends upon its electronegativity and upon the nature of its Lewis base ligands. The carbonyl ligand carbon charge becomes more positive as the metal electronegativity increases. The oxygen charge becomes more negative as the anionic cluster charge increases, and in so doing, yields the maximum anionic charge separation. The electronic properties of the terminal carbonyl ligands are similar to those of carbon monoxide, whereas the electronic properties of the bridging carbonyl ligands are similar to those of the carbonyl group found in aldehydes and ketones.

  17. First application of supported ionic liquid phase (SILP) catalysis for continuous methanol carbonylation

    DEFF Research Database (Denmark)

    Riisager, Anders; Jørgensen, Betina; Wasserscheid, Peter

    2006-01-01

    A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation.......A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation....

  18. Reaction of acid esters of methylenebis(phosphonous acid) with carbonyl compounds

    International Nuclear Information System (INIS)

    Novikova, Z.S.; Odinets, I.L.; Lutsenko, I.F.

    1987-01-01

    The reaction of methylenebis(phosphonites) containing two hydrophosphoryl groupings with aliphatic and aromatic aldehydes and ketones in the presence of alkali metal fluorides leads to methylenebis(α-hydroxyalkylphosphinates). The reaction of methylenebis(phosphonites) containing one hydrophosphoryl groupings with carbonyl compounds in the presence of alkali metal fluorides proceeds with the formation of a new type of heterocyclic phosphorus compound, viz., 1,2λ 3 ,4λ 5 -oxadiphospholanes. The reaction of acid esters of methylenebis(phosphonous) acid with carbonyl compounds in the presence of alkali metal alkoxides or a tertiary amine is accompanied by phosphinate-phosphonate rearrangement of the intermediately formed α-hydroxylalkylphosphinates

  19. Impaired cardiac SIRT1 activity by carbonyl stress contributes to aging-related ischemic intolerance.

    Directory of Open Access Journals (Sweden)

    Chunhu Gu

    Full Text Available Reactive aldehydes can initiate protein oxidative damage which may contribute to heart senescence. Sirtuin 1 (SIRT1 is considered to be a potential interventional target for I/R injury management in the elderly. We hypothesized that aldehyde mediated carbonyl stress increases susceptibility of aged hearts to ischemia/reperfusion (I/R injury, and elucidate the underlying mechanisms with a focus on SIRT1. Male C57BL/6 young (4-6 mo and aged (22-24 mo mice were subjected to myocardial I/R. Cardiac aldehyde dehydrogenase (ALDH2, SIRT1 activity and protein carbonyls were assessed. Our data revealed that aged heart exhibited increased endogenous aldehyde/carbonyl stress due to impaired ALDH2 activity concomitant with blunted SIRT1 activity (P<0.05. Exogenous toxic aldehydes (4-HNE exposure in isolated cardiomyocyte verified that aldehyde-induced carbonyl modification on SIRT1 impaired SIRT1 activity leading to worse hypoxia/reoxygenation (H/R injury, which could all be rescued by Alda-1 (ALDH2 activator (all P<0.05. However, SIRT1 inhibitor blocked the protective effect of Alda-1 on H/R cardiomyocyte. Interestingly, myocardial I/R leads to higher carbonylation but lower activity of SIRT1 in aged hearts than that seen in young hearts (P<0.05. The application of Alda-1 significantly reduced the carbonylation on SIRT1 and markedly improved the tolerance to in vivo I/R injury in aged hearts, but failed to protect Sirt1(+/- knockout mice against myocardial I/R injury. This was verified by Alda-1 treatment improved postischemic contractile function recovery in ex vivo perfused aged but not in Sirt1(+/- hearts. Thus, aldehyde/carbonyl stress is accelerated in aging heart. These results provide a new insight that impaired cardiac SIRT1 activity by carbonyl stress plays a critical role in the increased susceptibility of aged heart to I/R injury. ALDH2 activation can restore this aging-related myocardial ischemic intolerance.

  20. Nicotine and Carbonyl Emissions From Popular Electronic Cigarette Products: Correlation to Liquid Composition and Design Characteristics.

    Science.gov (United States)

    El-Hellani, Ahmad; Salman, Rola; El-Hage, Rachel; Talih, Soha; Malek, Nathalie; Baalbaki, Rima; Karaoghlanian, Nareg; Nakkash, Rima; Shihadeh, Alan; Saliba, Najat A

    2018-01-05

    Available in hundreds of device designs and thousands of flavors, electronic cigarette (ECIG) may have differing toxicant emission characteristics. This study assesses nicotine and carbonyl yields in the most popular brands in the U.S. market. These products included disposable, prefilled cartridge, and tank-based ECIGs. Twenty-seven ECIG products of 10 brands were procured and their power outputs were measured. The e-liquids were characterized for pH, nicotine concentration, propylene glycol/vegetable glycerin (PG/VG) ratio, and water content. Aerosols were generated using a puffing machine and nicotine and carbonyls were, respectively, quantified using gas chromatograph and high-performance liquid chromatography. A multiregression model was used to interpret the data. Nicotine yields varied from 0.27 to 2.91 mg/15 puffs, a range corresponding to the nicotine yield of less than 1 to more than 3 combustible cigarettes. Nicotine yield was highly correlated with ECIG type and brand, liquid nicotine concentration, and PG/VG ratio, and to a lower significance with electrical power, but not with pH and water content. Carbonyls, including the carcinogen formaldehyde, were detected in all ECIG aerosols, with total carbonyl concentrations ranging from 3.72 to 48.85 µg/15 puffs. Unlike nicotine, carbonyl concentrations were mainly correlated with power. In 15 puffs, some ECIG devices emit nicotine quantities that exceed those of tobacco cigarettes. Nicotine emissions vary widely across products but carbonyl emissions showed little variations. In spite of that ECIG users are exposed to toxicologically significant levels of carbonyl compounds, especially formaldehyde. Regression analysis showed the importance of design and e-liquid characteristics as determinants of nicotine and carbonyl emissions. Periodic surveying of characteristics of ECIG products available in the marketplace is valuable for understanding population-wide changes in ECIG use patterns over time. © The

  1. Dithioacetals as an Entry to Titanium-Alkylidene Chemistry: A New and Efficient Carbonyl Olefination.

    Science.gov (United States)

    Breit, Bernhard

    1998-03-02

    Wittig, Horner-Wadsworth-Emmons, Julia-Lythgoe, Tebbe, Grubbs, and Petasis-when it comes to carbonyl olefinations, these names are familiar to all chemistry students. In the future, the name Takeda will probably have to be added to this list. His recent work on the formation of titanium-alkylidene species from dithioacetals has provided organic chemists with a remarkable method for carbonyl olefination that is generally applicable under neutral to Lewis acidic conditions. © 1998 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  2. Ruthenium(II carbonyl compounds with the 4′-chloro-2,2′:6′,2′′-terpyridine ligand

    Directory of Open Access Journals (Sweden)

    Rajendhraprasad Tatikonda

    2017-04-01

    Full Text Available Two ruthenium carbonyl complexes with the 4′-chloro-2,2′:6′,2′′-terpyridine ligand (tpy-Cl, C15H10ClN3, i.e. [RuCl(tpy-Cl(CO2][RuCl3(CO3] (I [systematic name: cis-dicarbonylchlorido(4′-chloro-2,2′:6′,2′′-terpyridine-κ3Nruthenium(II fac-tricarbonyltrichloridoruthenate(II], and [RuCl2(tpy-Cl(CO2] (II [cis-dicarbonyl-trans-dichlorido(4′-chloro-2,2′:6′,2′′-terpyridine-κ2N1,N1′ruthenium(II], were synthesized and characterized by single-crystal X-ray diffraction. The RuII atoms in both centrosymmetric structures (I and (II display similar, slightly distorted octahedral coordination spheres. The coordination sphere in the complex cation in compound (I is defined by three N atoms of the tridentate tpy-Cl ligand, two carbonyl carbon atoms and one chlorido ligand; the charge is balanced by an octahedral [Ru(CO3Cl3]− counter-anion. In the neutral compound (II, the tpy-Cl ligand coordinates to the metal only through two of its N atoms. The coordination sphere of the RuII atom is completed by two carbonyl and two chlorido ligands. In the crystal structures of both (I and (II, weak C—H...Cl interactions are observed.

  3. (alpha-Diimine)tricarbonylhalorhenium complexes: the oxidation side

    Czech Academy of Sciences Publication Activity Database

    Drozdz, A.; Bubrin, M.; Fiedler, Jan; Záliš, Stanislav; Kaim, W.

    2012-01-01

    Roč. 41, č. 3 (2012), s. 1013-1019 ISSN 1477-9226 R&D Projects: GA MŠk LD11086; GA MŠk(CZ) ME10124 Institutional research plan: CEZ:AV0Z40400503 Keywords : (alpha-Diimine)tricarbonylhalorhenium complexes * electrochemistry * metal carbonyl complexes Subject RIV: CG - Electrochemistry Impact factor: 3.806, year: 2012

  4. Investigating magnetorheological properties of a mixture of two types of carbonyl iron powders suspended in an ionic liquid

    International Nuclear Information System (INIS)

    Dodbiba, Gjergj; Park, Hyun Seo; Okaya, Katsunori; Fujita, Toyohisa

    2008-01-01

    In this work, properties of a magnetorheological (MR) fluid, prepared by dispersing a mixture of two types of carbonyl iron powders (CIPs) of different sizes, in an ionic liquid (N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate) that is stable from 9 deg. C to ca. 300 deg. C, have been investigated. At first, the random packing density of the mixture was computed as function of mixing ratio of CIP, in order to find out the tendency of the variation. Next, several mixtures, all having the same weight, were prepared at various mixing ratios and dispersed in the ionic liquid, in order to experimentally find the most suitable mixing ratio of CIP. Then, the magnetic clusters of the synthesized MR fluids were observed by using a digital microscope equipped with two permanent magnets, whereas the MR properties were investigated by using a rotation viscometer equipped with a solenoid coil. The experimental results pointed out that the MR fluid with 60 wt% fraction of large particles exhibited the highest MR response

  5. Accounting for interactions and complex inter-subject dependency in estimating treatment effect in cluster-randomized trials with missing outcomes.

    Science.gov (United States)

    Prague, Melanie; Wang, Rui; Stephens, Alisa; Tchetgen Tchetgen, Eric; DeGruttola, Victor

    2016-12-01

    Semi-parametric methods are often used for the estimation of intervention effects on correlated outcomes in cluster-randomized trials (CRTs). When outcomes are missing at random (MAR), Inverse Probability Weighted (IPW) methods incorporating baseline covariates can be used to deal with informative missingness. Also, augmented generalized estimating equations (AUG) correct for imbalance in baseline covariates but need to be extended for MAR outcomes. However, in the presence of interactions between treatment and baseline covariates, neither method alone produces consistent estimates for the marginal treatment effect if the model for interaction is not correctly specified. We propose an AUG-IPW estimator that weights by the inverse of the probability of being a complete case and allows different outcome models in each intervention arm. This estimator is doubly robust (DR); it gives correct estimates whether the missing data process or the outcome model is correctly specified. We consider the problem of covariate interference which arises when the outcome of an individual may depend on covariates of other individuals. When interfering covariates are not modeled, the DR property prevents bias as long as covariate interference is not present simultaneously for the outcome and the missingness. An R package is developed implementing the proposed method. An extensive simulation study and an application to a CRT of HIV risk reduction-intervention in South Africa illustrate the method. © 2016, The International Biometric Society.

  6. Generalized approximate spin projection calculations of effective exchange integrals of the CaMn4O5 cluster in the S1 and S3 states of the oxygen evolving complex of photosystem II.

    Science.gov (United States)

    Isobe, H; Shoji, M; Yamanaka, S; Mino, H; Umena, Y; Kawakami, K; Kamiya, N; Shen, J-R; Yamaguchi, K

    2014-06-28

    Full geometry optimizations followed by the vibrational analysis were performed for eight spin configurations of the CaMn4O4X(H2O)3Y (X = O, OH; Y = H2O, OH) cluster in the S1 and S3 states of the oxygen evolution complex (OEC) of photosystem II (PSII). The energy gaps among these configurations obtained by vertical, adiabatic and adiabatic plus zero-point-energy (ZPE) correction procedures have been used for computation of the effective exchange integrals (J) in the spin Hamiltonian model. The J values are calculated by the (1) analytical method and the (2) generalized approximate spin projection (AP) method that eliminates the spin contamination errors of UB3LYP solutions. Using J values derived from these methods, exact diagonalization of the spin Hamiltonian matrix was carried out, yielding excitation energies and spin densities of the ground and lower-excited states of the cluster. The obtained results for the right (R)- and left (L)-opened structures in the S1 and S3 states are found to be consistent with available optical and magnetic experimental results. Implications of the computational results are discussed in relation to (a) the necessity of the exact diagonalization for computations of reliable energy levels, (b) magneto-structural correlations in the CaMn4O5 cluster of the OEC of PSII, (c) structural symmetry breaking in the S1 and S3 states, and (d) the right- and left-handed scenarios for the O-O bond formation for water oxidation.

  7. Properties of the open cluster system

    International Nuclear Information System (INIS)

    Janes, K.A.; Tilley, C.; Lynga, G.

    1988-01-01

    A system of weights corresponding to the precision of open cluster data is described. Using these weights, some properties of open clusters can be studied more accurately than was possible earlier. It is clear that there are three types of objects: unbound clusters, bound clusters in the thin disk, and older bound clusters. Galactic gradients of metallicity, longevity, and linear diameter are studied. Distributions at right angles to the galactic plane are discussed in the light of the different cluster types. The clumping of clusters in complexes is studied. An estimate of the selection effects influencing the present material of open cluster data is made in order to evaluate the role played by open clusters in the history of the galactic disk. 58 references

  8. High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP–oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

    Directory of Open Access Journals (Sweden)

    E. I. Howard

    2016-03-01

    Full Text Available Crystal diffraction data of heart fatty acid binding protein (H-FABP in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively. These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H...H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.

  9. Clustering Dycom

    KAUST Repository

    Minku, Leandro L.; Hou, Siqing

    2017-01-01

    baseline WC model is also included in the analysis. Results: Clustering Dycom with K-Means can potentially help to split the CC projects, managing to achieve similar or better predictive performance than Dycom. However, K-Means still requires the number

  10. Anomalous properties of technetium clusters

    International Nuclear Information System (INIS)

    Kryuchkov, S.V.

    1985-01-01

    On the basis of critical evaluation of literature data in the field of chemistry of technetium cluster compounds with ligands of a weak field a conclusion is made on specific, ''anomalous'' properties of technetium cluster complexes which consist in an increased ability of the given element to the formation of a series of binuclear and multinuclear clusters, similar in composition and structure and easily transforming in each other. The majority of technetium clusters unlike similar compounds of other elements are paramagnetic with one unpaired electron on ''metallic'' MO of loosening type. All theoretical conceptions known today on the electronic structure of technetium clusters are considered. It is pointed out, that the best results in the explanation of ''anomalous'' properties of technetium clusters can be obtained in the framework of nonempirical methods of self-consistent field taking into account configuration interactions. It is also shown, that certain properties of technetium clusters can be explained on the basis of qualitative model of Coulomb repulsion of metal atoms in clusters. The conclusion is made, that technetium position in the Periodic table, as well as recently detected technetium property to the decrease of effective charge on its atoms during M-M bond formation promote a high ability of the element to cluster formation both with weak field ligands and with strong field one

  11. H-D exchange in metal carbene complexes: Structure of cluster (μ-H)(μ-OCD3)Os3(CO)9{:C(CD3)NC2H8O}

    Science.gov (United States)

    Savkov, Boris; Maksakov, Vladimir; Kuratieva, Natalia

    2015-10-01

    X-ray and spectroscopic data for the new complex (μ-H)(μ-OCH3)Os3(CO)9{:C(CD3)NC2H8O} (2) obtained in the reaction of the (μ-H)(μ-Cl)Os3(CO)9{:C(CH3)NC2H8O} (1) with NaOCD3 in CD3OD solution are reported. It is shown that cluster 1 has the property of CH-acidity inherent of Fisher type carbenes. This had demonstrated using hydrogen deuterium exchange reaction in the presence of a strong base. Bridging chlorine to metoxide ligand substitution takes place during the reaction. The molecular structure of 2 is compared with known analogues.

  12. Ketene as a Reaction Intermediate in the Carbonylation of Dimethyl Ether to Methyl Acetate over Mordenite

    DEFF Research Database (Denmark)

    Rasmussen, Dominik Bjørn; Christensen, Jakob Munkholt; Temel, Burcin

    2015-01-01

    Unprecedented insight into the carbonylation of dimethyl ether over Mordenite is provided through the identification of ketene (CH2CO) as a reaction intermediate. The formation of ketene is predicted by detailed DFT calculations and verified experimentally by the observation of doubly deuterated ...

  13. Determination of protein carbonyls in plasma, cell extracts, tissue homogenates, isolated proteins

    DEFF Research Database (Denmark)

    Weber, Daniela; Davies, Michael J.; Grune, Tilman

    2015-01-01

    Protein oxidation is involved in regulatory physiological events as well as in damage to tissues and is thought to play a key role in the pathophysiology of diseases and in the aging process. Protein-bound carbonyls represent a marker of global protein oxidation, as they are generated by multiple...

  14. Formation and emissions of carbonyls during and following gas-phase ozonation of indoor materials

    DEFF Research Database (Denmark)

    Poppendieck, D.G.; Hubbard, H.F.; Weschler, Charles J.

    2007-01-01

    at concentrations of 1000 ppm in the inlet stream of experimental chambers. Fifteen target carbonyls were selected and measured as building ozonation by-products (BOBPs). During the 36 h that include the 16 h ozonation and 20 h persistence phase, the total BOBP mass released from flooring and wall coverings ranged...

  15. First application of supported ionic liquid phase (SILP) catalysis for continuous methanol carbonylation.

    Science.gov (United States)

    Riisager, Anders; Jørgensen, Betina; Wasserscheid, Peter; Fehrmann, Rasmus

    2006-03-07

    A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)2I2]-[BMIM]I-SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation.

  16. Unsuitability of using the DNPH-coated solid sorbent cartridge for determination of airborne unsaturated carbonyls

    Science.gov (United States)

    Ho, Steven Sai Hang; Ho, K. F.; Liu, W. D.; Lee, S. C.; Dai, W. T.; Cao, J. J.; Ip, H. S. S.

    2011-01-01

    Measurements of aldehydes and ketones are typically conducted by derivatization using sorbent cartridges coated with 2,4-dinitrophenylhydrazine (DNPH). The collected samples are eluted with acetonitrile and analyzed by high-pressure liquid chromatography coupled with an ultra-violet detector (HPLC/UV). This paper intends to examine artifacts about its suitability in identification of unsaturated carbonyls. Kinetic tests for acrolein, crotonaldehyde, methacrolein and methyl vinyl ketone (MVK) showed formations of carbonyl-DNP-hydrazone during sampling, which could further react with DNPH, resulting in undesired UV absorption products [e.g., carbonyl-DNP-hydrazone-DNPH (dimer) and 2(carbonyl-DNP-hydrazone)-DNPH (trimer)]. The dimerization and trimerization occurred for acrolein and MVK whereas only dimerization for crotonaldehyde and methacrolein. The polymerization products undoubtedly affect the integrity of the chromatogram, leading to misidentification and inaccurate quantification. Whether precautions taken during sampling and/or sample treatment could avoid or minimize this artifact has not been thoughtfully investigated. More often, such artifacts are usually overlooked by scientists when the data are reported.

  17. Antioxidative potential of Perna viridis and its protective role against ROS induced lipidperoxidation and protein carbonyl

    Digital Repository Service at National Institute of Oceanography (India)

    Jena, K.B.; Jagtap, T.G.; Verlecar, X.N.

    ) such as hydrogen peroxide (H2O2) and hydroxyl radical (OH•), and inhibition of lipid peroxidation (LPX) and protein carbonyl (PC). The scavenging activity of DPPH radical, H sub(2) O sub(2) and OH• radicals increased in dose dependent manner. The reducing power...

  18. Magnetically Recoverable Supported Ruthenium Catalyst for Hydrogenation of Alkynes and Transfer Hydrogenation of Carbonyl Compounds

    Science.gov (United States)

    A ruthenium (Ru) catalyst supported on magnetic nanoparticles (NiFe2O4) has been successfully synthesized and used for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The cata...

  19. [1,3-Bis(diphenyl-phosphino)pentane-κP,P']tetra-carbonyl-chromium(0).

    Science.gov (United States)

    Shawkataly, Omar Bin; Thangadurai, Daniel T; Pankhi, Mohd Aslam A; Shahinoor Dulal Islam, S M; Fun, Hoong-Kun

    2009-02-04

    In the title compound, [Cr(C(29)H(30)P(2))(CO)(4)], the Cr atom is octa-hedrally coordinated by four carbonyl ligands and one bidentate phosphine ligand, which is bounded as a chelate in a cis position. The average Cr-P and Cr-C bond lengths are 2.377 and 1.865 Å, respectively.

  20. Mechanism of stimulation of endogenous fermentation in yeast by carbonyl cyanide m-chlorophenylhydrazone

    NARCIS (Netherlands)

    Noshiro, A.; Purwin, C.; Laux, M.; Nicolaij, K.; Scheffers, W.A.; Holzer, H.

    1987-01-01

    Addition of the uncoupler and protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) to starved yeast cells starts endogenous alcoholic fermentation lasting about 20 min. Hexose 6-phosphates, fructose 2,6-bisphosphate, and pyruvate accumulate in less than 2 min after addition of CCCP from

  1. Efficient Conversion of Oximes to the Corresponding Carbonyl Compounds with Tetrabutylammonium Chromate under Aprotic Conditions

    International Nuclear Information System (INIS)

    Pourali, Ali Reza; Goli, Arezou

    2006-01-01

    The solubility in several solvents, mildness, simple work-up and absence of side reactions provide advantages of using TBAC in deoximation reactions. This is an efficient and selective method for homogeneous deoximation of structurally different compounds under the moderately acidic and aprotic conditions in high yields. Regeneration of ketones and aldehydes from their oximes has assumed added importance since the discovery of the Barton reaction in which oximes are produced at non-activated hydrocarbon sites. Also, their synthesis from non-carbonyl compounds, such as by nitrosation of an active methylene group, nitrosation of an α-halo carbonyl compound and condensation of a nitro-alkene with an aldehyde provides a valid alternative pathway to carbonyl compounds. Therefore, there has been a continued interest in the effective regeneration of carbonyl compounds from the corresponding oximes especially under mild conditions. Oxidative and reductive methods have been found to show advantages over the classical hydrolytic methods. Although many oxidizing agents have been used, only a limited number of methods are efficient because of the low solubility of these metallic reagents in most organic solvents

  2. Iron Dextran treatment does not induce serum protein carbonyls in the newborn pig

    Science.gov (United States)

    Oxidation of serum proteins can lead to carbonyl formation which alters their function and is often associated with stress-related diseases. Since it is recommended that all pigs reared in modern production facilities be given supplemental iron at birth to prevent anemia, and metals can catalyze th...

  3. Effect of carotenoid structure on excited-state dynamics of carbonyl carotenoids

    Czech Academy of Sciences Publication Activity Database

    Chábera, P.; Fuciman, M.; Hříbek, P.; Polívka, Tomáš

    2009-01-01

    Roč. 11, - (2009), s. 8795-8703 ISSN 1463-9076 R&D Projects: GA AV ČR IAA608170604 Institutional research plan: CEZ:AV0Z50510513 Keywords : excited-state dynamics * carbonyl carotenoids * femtosecond spectroscopy Subject RIV: BO - Biophysics Impact factor: 4.116, year: 2009

  4. Proteomic and carbonylation profile analysis of rat skeletal muscles following acute swimming exercise.

    Directory of Open Access Journals (Sweden)

    Francesca Magherini

    Full Text Available Previous studies by us and other groups characterized protein expression variation following long-term moderate training, whereas the effects of single bursts of exercise are less known. Making use of a proteomic approach, we investigated the effects of acute swimming exercise (ASE on protein expression and carbonylation patterns in two hind limb muscles: the Extensor Digitorum Longus (EDL and the Soleus, mostly composed of fast-twitch and slow-twitch fibres, respectively. Carbonylation is one of the most common oxidative modifications of proteins and a marker of oxidative stress. In fact, several studies suggest that physical activity and the consequent increase in oxygen consumption can lead to increase in reactive oxygen and nitrogen species (RONS production, hence the interest in examining the impact of RONS on skeletal muscle proteins following ASE. Results indicate that protein expression is unaffected by ASE in both muscle types. Unexpectedly, the protein carbonylation level was reduced following ASE. In particular, the analysis found 31 and 5 spots, in Soleus and EDL muscles respectively, whose carbonylation is reduced after ASE. Lipid peroxidation levels in Soleus were markedly reduced as well. Most of the decarbonylated proteins are involved either in the regulation of muscle contractions or in the regulation of energy metabolism. A number of hypotheses may be advanced to account for such results, which will be addressed in future studies.

  5. Interaction between alkaline earth cations and oxo-ligands. DFT study of the affinity of the Ca2+ cation for carbonyl ligands.

    Science.gov (United States)

    da Costa, Leonardo Moreira; Carneiro, José Walkimar de Mesquita; Romeiro, Gilberto Alves; Paes, Lilian Weitzel Coelho

    2011-02-01

    The affinity of the Ca(2+) ion for a set of substituted carbonyl ligands was analyzed with both the DFT (B3LYP/6-31+G(d)) and semi-empirical (PM6) methods. Two types of ligands were studied: a set of monosubstituted [O=CH(R)] and a set of disubstituted ligands [O=C(R)(2)] (R=H, F, Cl, Br, OH, OCH(3), CH(3), CN, NH(2) and NO(2)), with R either directly bound to the carbonyl carbon atom or to the para position of a phenyl ring. The interaction energy was calculated to quantify the affinity of the Ca(2+) cation for the ligands. Geometric and electronic parameters were correlated with the intensity of the metal-ligand interaction. The electronic nature of the substituent is the main parameter that determines the interaction energy. Donor groups make the interaction energy more negative (stabilizing the complex formed), while acceptor groups make the interaction energy less negative (destabilizing the complex formed).

  6. An embedded longitudinal multi-faceted qualitative evaluation of a complex cluster randomized controlled trial aiming to reduce clinically important errors in medicines management in general practice

    Directory of Open Access Journals (Sweden)

    Cresswell Kathrin M

    2012-06-01

    Full Text Available Abstract Background There is a need to shed light on the pathways through which complex interventions mediate their effects in order to enable critical reflection on their transferability. We sought to explore and understand key stakeholder accounts of the acceptability, likely impact and strategies for optimizing and rolling-out a successful pharmacist-led information technology-enabled (PINCER intervention, which substantially reduced the risk of clinically important errors in medicines management in primary care. Methods Data were collected at two geographical locations in central England through a combination of one-to-one longitudinal semi-structured telephone interviews (one at the beginning of the trial and another when the trial was well underway, relevant documents, and focus group discussions following delivery of the PINCER intervention. Participants included PINCER pharmacists, general practice staff, researchers involved in the running of the trial, and primary care trust staff. PINCER pharmacists were interviewed at three different time-points during the delivery of the PINCER intervention. Analysis was thematic with diffusion of innovation theory providing a theoretical framework. Results We conducted 52 semi-structured telephone interviews and six focus group discussions with 30 additional participants. In addition, documentary data were collected from six pharmacist diaries, along with notes from four meetings of the PINCER pharmacists and feedback meetings from 34 practices. Key findings that helped to explain the success of the PINCER intervention included the perceived importance of focusing on prescribing errors to all stakeholders, and the credibility and appropriateness of a pharmacist-led intervention to address these shortcomings. Central to this was the face-to-face contact and relationship building between pharmacists and a range of practice staff, and pharmacists’ explicitly designated role as a change agent

  7. Protein carbonyl content: a novel biomarker for aging in HIV/AIDS patients.

    Science.gov (United States)

    Kolgiri, Vaishali; Patil, Vinayak Wamanrao

    The major complications of "treated" Human Immunodeficiency Virus (HIV) infection are cardiovascular disease, malignancy, renal disease, liver disease, bone disease, and perhaps neurological complications, which are phenomena of the normal aging process occurring at an earlier age in the HIV-infected population. The present study is aimed to explore protein carbonyl content as a biomarker for detecting oxidative DNA damage induced ART toxicity and/or accelerated aging in HIV/AIDS patients. To investigate the potential of carbonyl content as a biomarker for detecting oxidative Deoxyribonucleic acid (DNA) damage induced Antiretroviral Theraphy (ART) toxicity and/or accelerated aging in HIV/AIDS patients. In this case-control study a total 600 subjects were included. All subjects were randomly selected and grouped as HIV-negative (control group) (n=300), HIV-infected ART naive (n=100), HIV-infected on first line ART (n=100), and HIV-infected on second line ART (n=100). Seronegative control subjects were age- and sex-matched with the ART naive patients and the two other groups. Carbonyl protein was determined by the method described in Levine et al. DNA damage marker 8-OH-dG was determined using 8-hydroxy-2-deoxy Guanosine StressXpress ELA Kit by StressMarq Biosciences. Protein carbonyl content levels and oxidative DNA damage were significantly higher (paging in HIV/AIDS patients. Larger studies are warranted to elucidate the role of carbonyl content as a biomarker for premature aging in HIV/AIDS patients. Copyright © 2016 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. All rights reserved.

  8. Cluster forcing

    DEFF Research Database (Denmark)

    Christensen, Thomas Budde

    The cluster theory attributed to Michael Porter has significantly influenced industrial policies in countries across Europe and North America since the beginning of the 1990s. Institutions such as the EU, OECD and the World Bank and governments in countries such as the UK, France, The Netherlands...... or management. Both the Accelerate Wales and the Accelerate Cluster programmes target this issue by trying to establish networks between companies that can be used to supply knowledge from research institutions to manufacturing companies. The paper concludes that public sector interventions can make...... businesses. The universities were not considered by the participating companies to be important parts of the local business environment and inputs from universities did not appear to be an important source to access knowledge about new product development or new techniques in production, distribution...

  9. Regional Innovation Clusters

    Data.gov (United States)

    Small Business Administration — The Regional Innovation Clusters serve a diverse group of sectors and geographies. Three of the initial pilot clusters, termed Advanced Defense Technology clusters,...

  10. Cluster analysis

    OpenAIRE

    Mucha, Hans-Joachim; Sofyan, Hizir

    2000-01-01

    As an explorative technique, duster analysis provides a description or a reduction in the dimension of the data. It classifies a set of observations into two or more mutually exclusive unknown groups based on combinations of many variables. Its aim is to construct groups in such a way that the profiles of objects in the same groups are relatively homogenous whereas the profiles of objects in different groups are relatively heterogeneous. Clustering is distinct from classification techniques, ...

  11. Inorganic heterocycles with two manganes or rhenium carbonyl units

    International Nuclear Information System (INIS)

    Kuellmer, V.; Vahrenkamp, H.

    1977-01-01

    From the reactive complexes [(CO) 4 M-E-Sn(CH 3 ) 3 ] 2 (M = Mn,Re; E = S,Se) with (CH 3 ) 2 PCl via the non-isolable four-membered ring intermediates [(CO) 4 M-E-P(CH 3 ) 2 ] 2 the six-membered heterocycles[-(CO) 4 M-P(CH 3 ) 2 -E-] 2 are formed. By use of (CH 3 ) 2 AsCl both the four-membered ring intermediates and the six-membered ring products can be isolated. The six-membered heterocycles can be opened by trimethylphosphine. (orig./HK) [de

  12. Two-step milling on the carbonyl iron particles and optimizing on the composite absorption

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yonggang, E-mail: xuyonggang221@163.com [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai 200438 (China); Yuan, Liming; Wang, Xiaobing [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai 200438 (China); Zhang, Deyuan [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2016-08-15

    The flaky carbonyl iron particles (CIPs) were prepared using a two-step milling process. The surface morphology was characterized by the scanning electron microscopy, the static magnetic property was evaluated on a vibrating sample magnetometer and X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The complex permittivity and permeability were measured using a vector network analyzer in the frequency range of 2–18 GHz. Then Hermite interpolation based on the calculated scattering parameters of the tested composite was used to derive the permittivity and permeability of the composite with random volume content. The results showed that the saturation magnetization value of the flaky CIPs decreased as the CIPs was changed to the flakes by high and low speeding milling. The diffraction peaks of the single α-Fe existed in the XRD pattern of CIPs, and the characteristic peaks was broad and the intensity of the diffraction pattern was lower as the high-speeding milling time increased. The sample H2L20 had the largest particle size, the average diameter was 8.64 μm, the thickness was 0.59 μm according to the fitted aspect ratio 14.65. The derived permittivity and permeability using the Hermite interpolation was accurate compared with the tested result, the deviation was about 0.39 + j0.45 and 2.5 + j0.51. Finally, the genetic algorithm was used to optimize the thickness of the CIPs composite of a wide absorbing band of 8–18 GHz. The optimized reflection loss (RL) result showed that the absorbing composites with thickness 1.47 mm had an excellent absorbing property (RL < −10 dB) in 8–18 GHz. - Graphical abstract: The property of absorber added two speeding milling CIPs could be enhanced using the genetic algorithm. - Highlights: • Flaky CIPs were prepared using a two-step milling process. • The permeability increased during the low speeding milling. • The aspect ratio of flaky CIPs increased in the optimized process

  13. Characterization of hydrocarbons, halocarbons and carbonyls in the atmosphere of Hong Kong.

    Science.gov (United States)

    Guo, H; Lee, S C; Louie, P K K; Ho, K F

    2004-12-01

    Ambient air quality measurements of 156 species including 39 alkanes, 32 alkenes, 2 alkynes, 24 aromatic hydrocarbons, 43 halocarbons and 16 carbonyls, were carried out for 120 air samples collected at two sampling stations (CW and TW) in 2001 throughout Hong Kong. Spatial variations of volatile organic compounds (VOCs) in the atmosphere were investigated. Levels of most alkanes and alkenes at TW site were higher than that at the CW site, while the BTEX concentrations at the two sites were close. The BTEX ratios at CW and TW were 1.6:10.1:1.0:1.6 and 2.1:10.8:1.0:2.0, respectively. For major halogenated hydrocarbons, the mean concentrations of chloromethane, CFCs 12 and 22 did not show spatial variations at the two sites. However, site-specific differences were observed for trichloroethene and tetrachloroethene. Furthermore, there were no significant differences for carbonyls such as formaldehyde, acetaldehyde and acetone between the two sites. The levels of selected hydrocarbons in winter were 1-5 times that in summer. There were no common seasonal trends for carbonyls in Hong Kong. The ambient level of formaldehyde, the most abundant carbonyl, was higher in summer. However, levels of acetaldehyde, acetone and benzaldehyde in winter were 1.6-3.8 times that in summer. The levels of CFCs 11 and 12, and chloromethane in summer were higher than that in winter. Strong correlation of most hydrocarbons with propene and n-butane suggested that the primary contributors of hydrocarbons were vehicular emissions in Hong Kong. In addition, gasoline evaporation, use of solvents, leakage of liquefied petroleum gas (LPG), natural gas leakage and other industrial emissions, and even biogenic emissions affected the ambient levels of hydrocarbons. The sources of halocarbons were mainly materials used in industrial processes and as solvents. Correlation analysis suggested that photochemical reactions made significant contributions to the ambient levels of carbonyls in summer whereas

  14. Synthesis of silyl iron hydride via Si-H activation and its dual catalytic application in the hydrosilylation of carbonyl compounds and dehydration of benzamides.

    Science.gov (United States)

    Ren, Shishuai; Xie, Shangqing; Zheng, Tingting; Wang, Yangyang; Xu, Shilu; Xue, Benjing; Li, Xiaoyan; Sun, Hongjian; Fuhr, Olaf; Fenske, Dieter

    2018-03-28

    The hydrido silyl iron complex (o-Ph 2 PC 6 H 4 SiMe 2 )Fe(PMe 3 ) 3 H (2) was obtained via the activation of the Si-H bond of the bidentate silyl ligand o-Ph 2 P(C 6 H 4 )SiMe 2 H (1) by Fe(PMe 3 ) 4 . 2 showed good to excellent catalytic activity in both the reduction of aldehydes/ketones and the dehydration of benzamide. In addition, with complex 2 as a catalyst, α,β-unsaturated carbonyls could be selectively reduced to the corresponding α,β-unsaturated alcohols. The mechanisms of the formation of 2 and the catalytic dehydration process are proposed and partly experimentally verified.

  15. Ionization of oriented carbonyl sulfide molecules by intense circularly polarized laser pulses

    DEFF Research Database (Denmark)

    Dimitrovski, Darko; Abu-Samha, Mahmoud; Madsen, Lars Bojer

    2011-01-01

    We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl sulfide molecules by circularly polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molec......We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl sulfide molecules by circularly polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction......-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons. In the following article [Phys. Rev. A 83, 023406 (2011)] the focus is to understand strong-field ionization from three-dimensionally-oriented asymmetric top molecules, in particular the suppression of electron...

  16. Molecular Active Sites in Heterogeneous Ir-La/C-Catalyzed Carbonylation of Methanol to Acetates.

    Science.gov (United States)

    Kwak, Ja Hun; Dagle, Robert; Tustin, Gerald C; Zoeller, Joseph R; Allard, Lawrence F; Wang, Yong

    2014-02-06

    We report that when Ir and La halides are deposited on carbon, exposure to CO spontaneously generates a discrete molecular heterobimetallic structure, containing an Ir-La covalent bond that acts as a highly active, selective, and stable heterogeneous catalyst for the carbonylation of methanol to produce acetic acid. This catalyst exhibits a very high productivity of ∼1.5 mol acetyl/mol Ir·s with >99% selectivity to acetyl (acetic acid and methyl acetate) without detectable loss in activity or selectivity for more than 1 month of continuous operation. The enhanced activity can be mechanistically rationalized by the presence of La within the ligand sphere of the discrete molecular Ir-La heterobimetallic structure, which acts as a Lewis acid to accelerate the normally rate-limiting CO insertion in Ir-catalyzed carbonylation. Similar approaches may provide opportunities for attaining molecular (single site) behavior similar to homogeneous catalysis on heterogeneous surfaces for other industrial applications.

  17. Influence of gamma radiation reaction on the hydroesterification of butenes catalyzed by metal carbonyls

    International Nuclear Information System (INIS)

    Velde, J. van der.

    1976-01-01

    In the hydro carboxylation reaction, which first has been studied by Reppe, olefine and acetylene compounds are processed with carbon monoxide and water at high pressures and high temperatures in the presence of metal carbonyls. This reaction can be enhanced considerably by application of ionizing radiation. Lower pressures and in particular lower temperatures can be used if gamma irradiation is performed during carboxylation. For the experiments a mixture of buten-1 and buten-2 as well as pure buten-1 and pure buten-2 has been used to study the behaviour of these olefines with respect to the isomerization of the reaction products and to the olefines not transformed in the reaction process. Replacing water, methanol has been used as a reaction component, thus obtaining directly the respective carbonyl acid esters, which can be analysed quantitatively and qualitatively with respect to their isomeric composition by gaschromatography. (orig./HK) [de

  18. Spectroscopic and theoretical studies on the aromaticity of pyrrol-2-yl-carbonyl conformers

    Science.gov (United States)

    Dubis, Alina T.; Wojtulewski, Sławomir; Filipkowski, Karol

    2013-06-01

    The aromaticity of s-cis and s-trans pyrrol-2-yl carbonyl conformers was studied by FT-IR, 1H NMR spectroscopy and DFT calculations at the B3LYP/6-311++G(d,p) level of theory. The Harmonic Oscillator Model of Aromaticity (HOMA) and Nucleus Independent Chemical Shift (NICS) indices were calculated to estimate π-electron delocalization in the pyrrole ring. The usefulness of infrared spectroscopy in the evaluation of the aromaticity of the homogeneous set of pyrroles is discussed. The influence of 2-substitution on different aspects of aromaticity and stability of the pyrrol-2-yl carbonyl conformers is also discussed. It is concluded that the substitution effect of the title pyrrole derivatives can be explained on the basis of theoretical and experimental measurements of π-electron delocalization, including IR data.

  19. Contribution to radiation-chemically catalyzed hydroformylation of butenes in the presence of metal carbonyls

    International Nuclear Information System (INIS)

    Joosten, L.

    1976-01-01

    In this paper a study is presented of the influence of gamma-radiation on the catalytic hydroformylation of olefines. As model olefines buten-1 and buten-2 as well as their mixtures have been used together with the catalysts di-cobalt octacarbonyle and rhodium (I) tristri phenyl-phosphine carbonyle hydride. In addition the catalytic activity of the VI. side group carbonyles Cr(CO) 6 , Mo(CO) 6 and W(CO) 6 has been studied under radiation chemical conditions. For this purpose a mixture of olefine, solvent (cyclo hexane) and calalyst has been pressurized and processed in a mixing autoklave together with a Co and H 2 (1:1) mixture, variing the reaction variables within certain limits. (orig.) [de

  20. Age-related carbonylation of fibrocartilage structural proteins drives tissue degenerative modification.

    Science.gov (United States)

    Scharf, Brian; Clement, Cristina C; Yodmuang, Supansa; Urbanska, Aleksandra M; Suadicani, Sylvia O; Aphkhazava, David; Thi, Mia M; Perino, Giorgio; Hardin, John A; Cobelli, Neil; Vunjak-Novakovic, Gordana; Santambrogio, Laura

    2013-07-25

    Aging-related oxidative stress has been linked to degenerative modifications in different organs and tissues. Using redox proteomic analysis and illustrative tandem mass spectrometry mapping, we demonstrate oxidative posttranslational modifications in structural proteins of intervertebral discs (IVDs) isolated from aging mice. Increased protein carbonylation was associated with protein fragmentation and aggregation. Complementing these findings, a significant loss of elasticity and increased stiffness was measured in fibrocartilage from aging mice. Studies using circular dichroism and intrinsic tryptophan fluorescence revealed a significant loss of secondary and tertiary structures of purified collagens following oxidation. Collagen unfolding and oxidation promoted both nonenzymatic and enzymatic degradation. Importantly, induction of oxidative modification in healthy fibrocartilage recapitulated the biochemical and biophysical modifications observed in the aging IVD. Together, these results suggest that protein carbonylation, glycation, and lipoxidation could be early events in promoting IVD degenerative changes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Design and fabrication of microfluidic mixer from carbonyl iron–PDMS composite membrane

    KAUST Repository

    Li, Jiaxing

    2010-10-12

    This paper introduces a carbonyl iron-PDMS (CI-PDMS) composite magnetic elastomer in which carbonyl iron (CI) particles are uniformly distributed in a PDMS matrix. The CI particles and the PDMS were mixed at different weight ratios and tested to determine the influence of CI concentration. The magnetic and mechanical properties of the magnetic elastomers were characterized, respectively, by vibrating-sample magnetometer and by tensile testing using a mechanical analyzer. The elastomer was found to exhibit high magnetization and good mechanical flexibility. The morphology and deformation of the CI-PDMS membrane also were observed. A magnetically actuated microfluidic mixer (that is, a micromixer) integrated with CI-PDMS elastomer membranes was successfully designed and fabricated. The high efficiency and quality of the mixing makes possible the impressive potential applications of this unique CI-PDMS material in microfluidic systems. © Springer-Verlag 2010.

  2. Alkylselenite-catalyzed Oxidative Carbonylation of Amines: Density Functional Theory Study

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Sun; Kim, Hoon Sik; Cheong, Minserk [Kyung Hee Univ., Seoul (Korea, Republic of)

    2012-11-15

    Ureas and carbamates have been conventionally produced by the reaction of amines with phosgene. However, phosgenation processes raise severe environmental concerns, which are attributed to the toxicity of phosgene and the formation of corrosive hydrogen chloride as a co-product. The considerable industrial interest in replacing current phosgene-based processes prompted several methods using non-phosgene routes including carbonylation of amines or nitro compounds and carbomethoxylation of amines with dialkylcarbonates. Among these, catalytic oxidative carbonylation of an amine in the presence of alcohol has been studied most extensively. Catalytic systems based on precious metals such as Rh and Pd are commonly used for this purpose, but most of these catalytic systems suffer from either low reactivity or severe reaction conditions such as high temperature and pressures. In conclusion, the facile change of selenium oxidation state by CO and O{sub 2} might be the main reason for the activity of the selenium catalyst for this reaction.

  3. Alkylselenite-catalyzed Oxidative Carbonylation of Amines: Density Functional Theory Study

    International Nuclear Information System (INIS)

    Hwang, Sun; Kim, Hoon Sik; Cheong, Minserk

    2012-01-01

    Ureas and carbamates have been conventionally produced by the reaction of amines with phosgene. However, phosgenation processes raise severe environmental concerns, which are attributed to the toxicity of phosgene and the formation of corrosive hydrogen chloride as a co-product. The considerable industrial interest in replacing current phosgene-based processes prompted several methods using non-phosgene routes including carbonylation of amines or nitro compounds and carbomethoxylation of amines with dialkylcarbonates. Among these, catalytic oxidative carbonylation of an amine in the presence of alcohol has been studied most extensively. Catalytic systems based on precious metals such as Rh and Pd are commonly used for this purpose, but most of these catalytic systems suffer from either low reactivity or severe reaction conditions such as high temperature and pressures. In conclusion, the facile change of selenium oxidation state by CO and O 2 might be the main reason for the activity of the selenium catalyst for this reaction

  4. Deoxygenative gem-difluoroolefination of carbonyl compounds with (chlorodifluoromethyltrimethylsilane and triphenylphosphine

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2014-02-01

    Full Text Available Background: 1,1-Difluoroalkenes cannot only be used as valuable precursors for organic synthesis, but also act as bioisosteres for enzyme inhibitors. Among various methods for their preparation, the carbonyl olefination with difluoromethylene phosphonium ylide represents one of the most straightforward methods.Results: The combination of (chlorodifluoromethyltrimethylsilane (TMSCF2Cl and triphenylphosphine (PPh3 can be used for the synthesis of gem-difluoroolefins from carbonyl compounds. Comparative experiments demonstrate that TMSCF2Cl is superior to (bromodifluoromethyltrimethylsilane (TMSCF2Br and (trifluoromethyltrimethylsilane (TMSCF3 in this reaction.Conclusion: Similar to many other Wittig-type gem-difluoroolefination reactions in the presence of PPh3, the reaction of TMSCF2Cl with aldehydes and activated ketones is effective.

  5. Criegee Intermediates: What Direct Production and Detection Can Teach Us About Reactions of Carbonyl Oxides

    Science.gov (United States)

    Taatjes, Craig A.

    2017-05-01

    The carbonyl oxide intermediates in the ozonolysis of alkenes, often known as Criegee intermediates, are potentially important reactants in Earth's atmosphere. For decades, careful analysis of ozonolysis systems was employed to derive an understanding of the formation and reactions of these species. Recently it has proved possible to synthesize at least some of these intermediates separately from ozonolysis, and hence to measure their reaction kinetics directly. Direct measurements have allowed new or more detailed understanding of each type of gas-phase reaction that carbonyl oxides undergo, often acting as a complement to highly detailed ozonolysis experiments. Moreover, the use of direct characterization methods to validate increasingly accurate theoretical investigations can enhance their impact well beyond the set of specific reactions that have been measured. Reactions that initiate particles or fuel their growth could be a new frontier for direct measurements of Criegee intermediate chemistry.

  6. Analysis of protein carbonylation - pitfalls and promise in commonly used methods

    DEFF Research Database (Denmark)

    Rogowska-Wrzesinska, A.; Wojdyla, K.; Nedic, O.

    2014-01-01

    that research scientists are becoming more eager to be able to measure accurately the level of oxidized protein in biological materials, and to determine the precise site of the oxidative attack on the protein, in order to get insights into the molecular mechanisms involved in the progression of diseases....... Several methods for measuring protein carbonylation have been implemented in different laboratories around the world. However, to date no methods prevail as the most accurate, reliable, and robust. The present paper aims at giving an overview of the common methods used to determine protein carbonylation...... in biological material as well as to highlight the limitations and the potential. The ultimate goal is to give quick tips for a rapid decision making when a method has to be selected and taking into consideration the advantage and drawback of the methods....

  7. Analysis of protein carbonylation-pitfalls and promise in commonly used methods

    DEFF Research Database (Denmark)

    Rogowska-Wrzesinska, Adelina; Wojdyla, K; Nedić, O

    2014-01-01

    that research scientists are becoming more eager to be able to measure accurately the level of oxidized protein in biological materials, and to determine the precise site of the oxidative attack on the protein, in order to get insights into the molecular mechanisms involved in the progression of diseases....... Several methods for measuring protein carbonylation have been implemented in different laboratories around the world. However, to date no methods prevail as the most accurate, reliable, and robust. The present paper aims at giving an overview of the common methods used to determine protein carbonylation...... in biological material as well as to highlight the limitations and the potential. The ultimate goal is to give quick tips for a rapid decision making when a method has to be selected and taking into consideration the advantage and drawback of the methods....

  8. Novel Routes to Ethylene Glycol Synthesis via Acid-Catalyzed Carbonylation of Formaldehyde and Dimethoxymethane

    OpenAIRE

    Celik, Fuat Emin

    2010-01-01

    Carbon-carbon bond forming carbonylation reactions were investigated as candidates to replace ethene epoxidation as the major source of ethylene glycol production. This work was motivated by the potentially lower cost of carbon derived from synthesis gas as compared to ethylene. Synthesis gas can be produced from relatively abundant and cheap natural gas, coal, and biomass resources whereas ethylene is derived from increasingly scarce and expensive crude oil. From synthesis gas, a range of...

  9. Carbonylative Heck Reactions Using CO Generated ex Situ in a Two-Chamber System

    DEFF Research Database (Denmark)

    Hermange, Philippe; Gøgsig, Thomas; Lindhardt, Anders Thyboe

    2011-01-01

    A carbonylative Heck reaction of aryl iodides and styrene derivatives employing a two-chamber system using a stable, crystalline, and nontransition metal based carbon monoxide source is reported. By applying near-stoichiometric amounts of the carbon monoxide precursor, an effective exploitation o...... of the hazardous CO gas is obtained affording chalcone derivatives in good yields. Application to isotope labeling, incorporating 13CO, was further established....

  10. Organocatalyzed Asymmetric α-Oxidation, α-Aminoxylation and α-Amination of Carbonyl Compounds

    OpenAIRE

    Worawan Bhanthumnavin; Tirayut Vilaivan

    2010-01-01

    Organocatalytic asymmetric α-oxidation and amination reactions of carbonyl compounds are highly useful synthetic methodologies, especially in generating chiral building blocks that previously have not been easily accessible by traditional methods. The concept is relatively new and therefore the list of new catalysts, oxidizing and aminating reagents, as well as new substrates, are expanding at an amazing rate. The scope of this review includes new reactions and catalysts, mechanistic aspects ...

  11. The interaction of metal carbonyl compounds with organic polymers and monomers

    OpenAIRE

    Lyons, Michael P.

    1993-01-01

    The photochemistry of W(CO)6, Mo(CO)6, and Cr(CO)6 in the presence of monomeric and polymeric triphenylphosphine ligands was investigated in toluene solution, using laser flash photolysis with 355nm excitation. The mechanism and kinetics of interaction of the primary photoproducts M(CO)5(toluene) (M = W, Mo, or Cr) with the various monomeric ligands were investigated. Interaction of the metal carbonyl photofragments with various homopolymers is also discussed. The polymerisation methods used ...

  12. Plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids

    Czech Academy of Sciences Publication Activity Database

    Sedlačík, M.; Pavlínek, V.; Lehocký, M.; Mráček, A.; Grulich, O.; Švrčinová, Petra; Filip, Petr; Vesel, A.

    2011-01-01

    Roč. 387, 1-3 (2011), s. 99-103 ISSN 0927-7757 Grant - others:GA ČR(CZ) GD104/09/H080; OP VaVpI(XE) CZ.1.05/2.1.00/03.0111 Program:GD Institutional research plan: CEZ:AV0Z20600510 Keywords : carbonyl iron * magnetorheological fluid * plasma * viscoelasticity Subject RIV: BK - Fluid Dynamics Impact factor: 2.236, year: 2011

  13. Expression, purification, crystallization and preliminary X-ray diffraction analysis of carbonyl reductase from Candida parapsilosis ATCC 7330

    International Nuclear Information System (INIS)

    Aggarwal, Nidhi; Mandal, P. K.; Gautham, Namasivayam; Chadha, Anju

    2013-01-01

    The expression, purification, crystallization, preliminary X-ray diffraction and molecular-replacement studies on C. parapsilosis carbonyl reductase are reported. The NAD(P)H-dependent carbonyl reductase from Candida parapsilosis ATCC 7330 catalyses the asymmetric reduction of ethyl 4-phenyl-2-oxobutanoate to ethyl (R)-4-phenyl-2-hydroxybutanoate, a precursor of angiotensin-converting enzyme inhibitors such as Cilazapril and Benazepril. The carbonyl reductase was expressed in Escherichia coli and purified by GST-affinity and size-exclusion chromatography. Crystals were obtained by the hanging-drop vapour-diffusion method and diffracted to 1.86 Å resolution. The asymmetric unit contained two molecules of carbonyl reductase, with a solvent content of 48%. The structure was solved by molecular replacement using cinnamyl alcohol dehydrogenase from Saccharomyces cerevisiae as a search model

  14. Molecular Nickel Phosphide Carbonyl Nanoclusters: Synthesis, Structure, and Electrochemistry of [Ni11P(CO)18]3- and [H6-nNi31P4(CO)39]n- (n = 4 and 5).

    Science.gov (United States)

    Capacci, Chiara; Ciabatti, Iacopo; Femoni, Cristina; Iapalucci, Maria Carmela; Funaioli, Tiziana; Zacchini, Stefano; Zanotti, Valerio

    2018-02-05

    The reaction of [NEt 4 ] 2 [Ni 6 (CO) 12 ] in thf with 0.5 equiv of PCl 3 affords the monophosphide [Ni 11 P(CO) 18 ] 3- that in turn further reacts with PCl 3 resulting in the tetra-phosphide carbonyl cluster [HNi 31 P 4 (CO) 39 ] 5- . Alternatively, the latter can be obtained from the reaction of [NEt 4 ] 2 [Ni 6 (CO) 12 ] in thf with 0.8-0.9 equiv of PCl 3 . The [HNi 31 P 4 (CO) 39 ] 5- penta-anion is reversibly protonated by strong acids leading to the [H 2 Ni 31 P 4 (CO) 39 ] 4- tetra-anion, whereas deprotonation affords the [Ni 31 P 4 (CO) 39 ] 6- hexa-anion. The latter is reduced with Na/naphthalene yielding the [Ni 31 P 4 (CO) 39 ] 7- hepta-anion. In order to shed light on the polyhydride nature and redox behavior of these clusters, electrochemical and spectroelectrochemical studies were carried out on [Ni 11 P(CO) 18 ] 3- , [HNi 31 P 4 (CO) 39 ] 5- , and [H 2 Ni 31 P 4 (CO) 39 ] 4- . The reversible formation of the stable [Ni 11 P(CO) 18 ] 4- tetra-anion is demonstrated through the spectroelectrochemical investigation of [Ni 11 P(CO) 18 ] 3- . The redox changes of [HNi 31 P 4 (CO) 39 ] 5- show features of chemical reversibility and the vibrational spectra in the ν CO region of the nine redox states of the cluster [HNi 31 P 4 (CO) 39 ] n- (n = 3-11) are reported. The spectroelectrochemical investigation of [H 2 Ni 31 P 4 (CO) 39 ] 4- revealed the presence of three chemically reversible reduction processes, and the IR spectra of [H 2 Ni 31 P 4 (CO) 39 ] n- (n = 4-7) have been recorded. The different spectroelectrochemical behavior of [HNi 31 P 4 (CO) 39 ] 5- and [H 2 Ni 31 P 4 (CO) 39 ] 4- support their formulations as polyhydrides. Unfortunately, all the attempts to directly confirm their poly hydrido nature by 1 H NMR spectroscopy failed, as previously found for related large metal carbonyl clusters. Thus, the presence and number of hydride ligands have been based on the observed protonation/deprotonation reactions and the spectroelectrochemical

  15. Nuclear clustering - a cluster core model study

    International Nuclear Information System (INIS)

    Paul Selvi, G.; Nandhini, N.; Balasubramaniam, M.

    2015-01-01

    Nuclear clustering, similar to other clustering phenomenon in nature is a much warranted study, since it would help us in understanding the nature of binding of the nucleons inside the nucleus, closed shell behaviour when the system is highly deformed, dynamics and structure at extremes. Several models account for the clustering phenomenon of nuclei. We present in this work, a cluster core model study of nuclear clustering in light mass nuclei

  16. Selectivity of a heterogeneous rhodium catalyst for the carbonylation of monohydric alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, B; Scurrell, M S

    1977-01-01

    Selectivity of a heterogeneous rhodium catalyst for the carbonylation of monohydric alcohols with carbon monoxide in the presence of the corresponding alkyl iodides as promotors was studied in a glass reactor at approx. 0.05:1 alcohol/carbon monoxide ratio. The 1% by wt rhodium-zeolite catalyst was prepared by immersing a Linde molecular sieve zeolite Type 13X in rhodium trichloride at 80/sup 0/C for 15 hr. Methanol was converted to methyl acetate at 433/sup 0/-513/sup 0/K with selectivites > 90% even at the highest temperatures, and dimethyl ether was by-produced. In the absence of methyl iodide, the carbonylation rate decreased drastically but the dehydration was virtually unaffected. The selectivity for ethanol carbonylation decreased from 99% at 383/sup 0/K to 6% at 523/sup 0/K due to the formation of ethylene (predominant at > 470/sup 0/K) and diethyl ether. The only product of the reaction with propan-2-ol studied at 433/sup 0/ or 473/sup 0/K was propene with 100% conversion at 473/sup 0/K. These results are consistent with the relative ease of reactant dehydration on polar catalysts. Table and 13 references.

  17. Gas chromatographic analysis of reactive carbonyl compounds formed from lipids upon UV-irradiation

    International Nuclear Information System (INIS)

    Dennis, K.J.; Shibamoto, T.

    1990-01-01

    Peroxidation of lipids produces carbonyl compounds; some of these, e.g., malonaldehyde and 4-hydroxynonenal, are genotoxic because of their reactivity with biological nucleophiles. Analysis of the reactive carbonyl compounds is often difficult. The methylhydrazine method developed for malonaldehyde analysis was applied to simultaneously measure the products formed from linoleic acid, linolenic acid, arachidonic acid, and squalene upon ultraviolet-irradiation (UV-irradiation). The photoreaction products, saturated monocarbonyl, alpha,beta-unsaturated carbonyls, and beta-dicarbonyls, were derivatized with methylhydrazine to give hydrazones, pyrazolines, and pyrazoles, respectively. The derivatives were analyzed by gas chromatography and gas chromatography-mass spectrometry. Lipid peroxidation products identified included formaldehyde, acetaldehyde, acrolein, malonaldehyde, n-hexanal, and 4-hydroxy-2-nonenal. Malonaldehyde levels formed upon 4 hr of irradiation were 0.06 micrograms/mg from squalene, 2.4 micrograms/mg from linolenic acid, and 5.7 micrograms/mg from arachidonic acid. Significant levels of acrolein (2.5 micrograms/mg) and 4-hydroxy-2-nonenal (0.17 micrograms/mg) were also produced from arachidonic acid upon 4 hr irradiation

  18. A carnosine intervention study in overweight human volunteers: bioavailability and reactive carbonyl species sequestering effect

    Science.gov (United States)

    Regazzoni, Luca; de Courten, Barbora; Garzon, Davide; Altomare, Alessandra; Marinello, Cristina; Jakubova, Michaela; Vallova, Silvia; Krumpolec, Patrik; Carini, Marina; Ukropec, Jozef; Ukropcova, Barbara; Aldini, Giancarlo

    2016-06-01

    Carnosine is a natural dipeptide able to react with reactive carbonyl species, which have been recently associated with the onset and progression of several human diseases. Herein, we report an intervention study in overweight individuals. Carnosine (2 g/day) was orally administered for twelve weeks in order to evaluate its bioavailability and metabolic fate. Two carnosine adducts were detected in the urine samples of all subjects. Such adducts are generated from a reaction with acrolein, which is one of the most toxic and reactive compounds among reactive carbonyl species. However, neither carnosine nor adducts have been detected in plasma. Urinary excretion of adducts and carnosine showed a positive correlation although a high variability of individual response to carnosine supplementation was observed. Interestingly, treated subjects showed a significant decrease in the percentage of excreted adducts in reduced form, accompanied by a significant increase of the urinary excretion of both carnosine and carnosine-acrolein adducts. Altogether, data suggest that acrolein is entrapped in vivo by carnosine although the response to its supplementation is possibly influenced by individual diversities in terms of carnosine dietary intake, metabolism and basal production of reactive carbonyl species.

  19. Nitrite promotes protein carbonylation and Strecker aldehyde formation in experimental fermented sausages: are both events connected?

    Science.gov (United States)

    Villaverde, A; Ventanas, J; Estévez, M

    2014-12-01

    The role played by curing agents (nitrite, ascorbate) on protein oxidation and Strecker aldehyde formation is studied. To fulfill this objective, increasing concentrations of nitrite (0, 75 and 150ppm) and ascorbate (0, 250 and 500ppm) were added to sausages subjected to a 54day drying process. The concurrence of intense proteolysis, protein carbonylation and formation of Strecker aldehydes during processing of sausages suggests that α-aminoadipic semialdehyde (AAS) and γ-glutamic semialdehyde (GGS) may be implicated in the formation of Strecker aldehydes. The fact that nitrite (150ppm, ingoing amount) significantly promoted the formation of protein carbonyls at early stages of processing and the subsequent formation of Strecker aldehydes provides strength to this hypothesis. Ascorbate (125 and 250ppm) controlled the overall extent of protein carbonylation in sausages without declining the formation of Strecker aldehydes. These results may contribute to understanding the chemistry fundamentals of the positive influence of nitrite on the flavor and overall acceptability of cured muscle foods. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air

    Science.gov (United States)

    Lui, K. H.; Ho, Steven Sai Hang; Louie, Peter K. K.; Chan, C. S.; Lee, S. C.; Hu, Di; Chan, P. W.; Lee, Jeffrey Chi Wai; Ho, K. F.

    2017-03-01

    Gas-phase formaldehyde (HCHO) is an intermediate and a sensitive indicator for volatile organic compounds (VOCs) oxidation, which drives tropospheric ozone production. Effective photochemical pollution control strategies demand a thorough understanding of photochemical oxidation precursors, making differentiation between sources of primary and secondary generated HCHO inevitable. Spatial and seasonal variations of airborne carbonyls based on two years of measurements (2012-2013), coupled with a correlation-based HCHO source apportionment analysis, were determined for three sampling locations in Hong Kong (denoted HT, TC, and YL). Formaldehyde and acetaldehyde were the two most abundant compounds of the total quantified carbonyls. Pearson's correlation analysis (r > 0.7) implies that formaldehyde and acetaldehyde possibly share similar sources. The total carbonyl concentration trends (HT rural). A regression analysis further quantifies the relative primary HCHO source contributions at HT (∼13%), TC (∼21%), and YL (∼40%), showing more direct vehicular emissions in urban than rural areas. Relative secondary source contributions at YL (∼36%) and TC (∼31%) resemble each other, implying similar urban source contributions. Relative background source contributions at TC could be due to a closed structure microenvironment that favors the trapping of HCHO. Comparable seasonal differences are observed at all stations. The results of this study will aid in the development of a new regional ozone (O3) control policy, as ambient HCHO can enhance O3 production and also be produced from atmospheric VOCs oxidation (secondary HCHO).