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Sample records for 2h 3h 4h

  1. Heats of formation and thermodynamic functions for C2H, C3H, and C4H from 300 K to 6000 K

    NASA Technical Reports Server (NTRS)

    Saturno, A. F.

    1982-01-01

    A review of the energy level and heat of formation data for the species C2H, C3H, and C4H is given. The procedure for computing thermochemical data from partition function is also reviewed. Working expressions for approximate partition functions, free-energy function, enthalpy function, and heat capacity for a linear polyatomic species are presented.

  2. Ab initio studies on cyanoacetylenes of astrochemical interest: [Y(Ctbnd C)CN, Y dbnd C2H5, C3H7, C4H9, F, Cl, Br and CN

    NASA Astrophysics Data System (ADS)

    Kodi Ramanah, D.; Surajbali, P.; Rhyman, L.; Alswaidan, I. A.; Fun, H.-K.; Somanah, R.; Ramasami, P.

    2016-01-01

    Theoretical studies were performed on seven potential interstellar and circumstellar substituted cyanoacetylenes, Y(Ctbnd C)CN [Y = C2H5, C3H7, C4H9, F, Cl, Br and CN]. Geometry optimizations were carried out using the DFT/B3LYP, the CCSD and CCSD(T) levels of theory. The cc-pVTZ basis set was used for all atoms. Frequency computations were also carried out at the same level of theory as for the optimization to check the nature of the stationary points. The molecular and spectroscopic parameters of the cyanoacetylenes were computed. An analysis of these parameters is in line with the satisfactory performance of the B3LYP/cc-pVTZ level compared to the golden standard, the CCSD(T) level. The theoretical data reported in this work should facilitate future identifications of these cyanoacetylenes in extraterrestrial locations. Plausible mechanisms for the formation of these molecules have been proposed.

  3. Theoretical microwave spectral constants for C3H/+/ and C4H/+/

    NASA Technical Reports Server (NTRS)

    Wilson, S.; Green, S.

    1980-01-01

    A number of linear conjugated carbon chain molecules have been observed in the interstellar gas. It has been suggested that ion molecule chemistry schemes may explain the formation of these compounds. In the present paper, theoretical bond lengths and rotation constants are obtained for C3H(+) and C4H(+). Calculations for C3 are used to assess the accuracy of the former. Recent results for C2H(+) are examined.

  4. Synthesis, structural elucidation and spectroscopic analysis of 3a,8b-dihydroxy-4-oxo-1H,2H,3H,3aH,4H,8bH-indeno[1,2-d]imidazolidin-2-iminium chloride

    NASA Astrophysics Data System (ADS)

    Uma Devi, T.; Priya, S.; Selvanayagam, S.; Ravikumar, K.; Anitha, K.

    2012-11-01

    Ninhydrin guanidinium chloride (3a,8b-dihydroxy-4-oxo-1H,2H,3H,3aH,4H,8bH-indeno [1,2-d]imidazolidin-2-iminium chloride) a semiorganic crystal was synthesized. The structure was determined using X-ray single crystal technique. Comparisons between the FT-IR spectrum of ninhydrin guanidinium chloride with ninhydrin were made. Melting point was found using thermal measurements. The molecular geometry, vibrational frequencies and Mulliken charges of the compound in the ground state have been calculated by the density functional theory (DFT) method with 3-21G(d,p) basis set and theoretical frequencies were compared with the experimental FT-IR spectrum. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, natural bond orbitals (NBO) and thermodynamic properties at various temperatures of the compound were investigated by theoretical calculations.

  5. Viscosity, Second pVT-Virial Coefficient, and Diffusion of Pure and Mixed Small Alkanes CH4, C2H6, C3H8, n-C4H10, i-C4H10, n-C5H12, i-C5H12, and C(CH3)4 Calculated by Means of an Isotropic Temperature-Dependent Potential. I. Pure Alkanes

    NASA Astrophysics Data System (ADS)

    Zarkova, L.; Hohm, U.; Damyanova, M.

    2006-09-01

    Reference tables of second pVT-virial coefficients B(T ), viscosity η(T ), and self-diffusion ρD(T ) are given for all neat alkanes CnH2n+2, n <6, for temperatures T ⩽1200K starting at 100K for CH4, 150K for C2H6, and 180K for C3H8, n-C4H10, i-C4H10, n-C5H12, i-C5H12, and C(CH3)4. Restricting ourselves to low densities the thermophysical properties are calculated by means of an isotropic (n-6) Lennard-Jones temperature dependent potential (LJTDP). In this model the potential well depth ɛeff(T ) and the separation at minimum energy Rm(eff)(T) are explicitly temperature dependent, whereas the repulsive term n >12 is independent of T. The LJTDP has been used before in order to construct reference tables of thermophysical properties of neat gases [Zarkova and Hohm, J. Phys. Chem. Ref. Data 31, 183 (2002)] and binary mixtures [Zarkova, Hohm, and Damyanova, J. Phys. Chem. Ref. Data 32, 1591 (2003)]. However, those studies were restricted to atoms and globularly shaped nondipolar molecules. Here the approach is extended to elongated, not necessarily spherically symmetric, and in part slightly dipolar molecules. As in previous works the potential parameters ɛ(eff)(T), Rm(eff)(T), and n are determined by minimizing the root-mean-square deviation between calculated and experimentally obtained thermophysical properties B(T ), η(T ), ρD(T ), and the second acoustic virial coefficient β(T ) normalized to their experimental error. In extension of our previous efforts we present a thorough statistical analysis of the experimental input data which gives us the possibility to select primary data which could be used to build up a database.

  6. Rotational spectroscopy of 2H,3H-perfluoropentane

    NASA Astrophysics Data System (ADS)

    Duong, Chinh H.; Obenchain, Daniel A.; Cooke, S. A.; Novick, Stewart E.

    2016-06-01

    The structure of 2H,3H-perfluoropentane, CF3CHFCHFCF2CF3, has been determine by a combination of Chirp-pulsed Fourier transform microwave (CP-FTMW) spectroscopy and cavity FTMW spectroscopy. Of the four possible stereoisomers, only the enantiomeric pair (R,R)/(S,S) were observed experimentally; there was no spectroscopic evidence for the enantiomeric pair (R,S)/(S,R). The conformeric structure of the (R,R)/(S,S) stereoisomer(s) was that of partial helices with C-C-C-C dihedral angles of 12° (helical) and 1° (staggered).

  7. One dimensional 1H, 2H and 3H

    NASA Astrophysics Data System (ADS)

    Vidal, A. J.; Astrakharchik, G. E.; Vranješ Markić, L.; Boronat, J.

    2016-05-01

    The ground-state properties of one-dimensional electron-spin-polarized hydrogen 1H, deuterium 2H, and tritium 3H are obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are calculated for a wide range of linear densities. The pair correlation function and the static structure factor are obtained and interpreted within the framework of the Luttinger liquid theory. We report the density dependence of the Luttinger parameter and use it to identify different physical regimes: Bogoliubov Bose gas, super-Tonks–Girardeau gas, and quasi-crystal regimes for bosons; repulsive, attractive Fermi gas, and quasi-crystal regimes for fermions. We find that the tritium isotope is the one with the richest behavior. Our results show unambiguously the relevant role of the isotope mass in the properties of this quantum system.

  8. Study of the $\\tau^- to 3h^- 2h^+ \

    SciTech Connect

    Aubert, Bernard; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; Palano, A.; Pappagallo, M.; Pompili, A.; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; Eigen, G.; Ofte, I.; Stugu, B. /more authors..

    2005-05-04

    The branching fraction of the {tau}{sup -} {yields} 3h{sup -} 2h{sup +} {nu}{sub {tau}} decay (h = {pi}, K) is measured with the BABAR detector to be (8.56 {+-} 0.05 {+-} 0.42) x 10{sup -4}, where the first error is statistical and the second systematic. The observed structure of this decay is significantly different from the phase space prediction, with the {rho} resonance playing a strong role. The decay {tau}{sup -} {yields} f{sub 1}(1285){pi}{sup -}{nu}{sub {tau}}, with the f{sub 1}(1285) meson decaying to four charged pions, is observed and the branching fraction is measured to be (3.9 {+-} 0.7 {+-} 0.5) x 10{sup -4}.

  9. Indirect Approach To The {sup 2}H(d,p){sup 3}H Reaction Study

    SciTech Connect

    Sparta, R.; Pizzone, R. G.; Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Aliotta, M.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Kiss, G.; McCleskey, M.; Trache, L.

    2010-11-24

    In order to understand primordial and stellar nucleosynthesis, we have studied {sup 2}H(d,p){sup 3}H reaction at 0.4 MeV down to astrophysical energies. Knowledge of its S-factor is interesting also to plan reactions for fusion reactors to produce energy. The {sup 2}H(d,p)H reaction has been studied through the Trojan Horse Method applied to the three-body reaction {sup 2}H(He,pt)H, at beam energy of 17 MeV. Once selection of protons and tritons detected in coincidence and the selection of quasi-free events, the obtained S-factor is compared with direct measurements. Such data are in agreement with the direct ones and a pole invariance test has been obtained comparing the present results with another {sup 2}H(d,p){sup 3}H THM measurements, where a different spectator particle was employed.

  10. Theoretical study of radiative electron attachment to CN, C2H, and C4H radicals.

    PubMed

    Douguet, Nicolas; Fonseca dos Santos, S; Raoult, Maurice; Dulieu, Olivier; Orel, Ann E; Kokoouline, Viatcheslav

    2015-06-21

    A first-principle theoretical approach to study the process of radiative electron attachment is developed and applied to the negative molecular ions CN(-), C4H(-), and C2H(-). Among these anions, the first two have already been observed in the interstellar space. Cross sections and rate coefficients for formation of these ions by direct radiative electron attachment to the corresponding neutral radicals are calculated. For the CN molecule, we also considered the indirect pathway, in which the electron is initially captured through non-Born-Oppenheimer coupling into a vibrationally resonant excited state of the anion, which then stabilizes by radiative decay. We have shown that the contribution of the indirect pathway to the formation of CN(-) is negligible in comparison to the direct mechanism. The obtained rate coefficients for the direct mechanism at 30 K are 7 × 10(-16) cm(3)/s for CN(-), 7 × 10(-17) cm(3)/s for C2H(-), and 2 × 10(-16) cm(3)/s for C4H(-). These rates weakly depend on temperature between 10 K and 100 K. The validity of our calculations is verified by comparing the present theoretical results with data from recent photodetachment experiments. PMID:26093561

  11. Quantum chemical study of ternary mixtures of: HNO3:H2SO4:H2O

    NASA Astrophysics Data System (ADS)

    Verdes, M. A.; Gómez, P. C.; Gálvez, O.

    2009-04-01

    Water, nitric acid and sulfuric acid are important atmospheric species as individual species and as hydrogen-bonded aggregates involved in many physical-chemical processes both superficial and bulk. The importance of heterogeneous chemical reactions taking place on ice surfaces, either solid water or solid water plus nitric or sulfuric acid, is well established now in relation to the ozone-depleting mechanisms. Also the importance of liquid droplets formed by HNO3.H2SO4.H2O as components of PSC was soon recognized [1-3]. Finally the physical properties of finely divided aqueous systems is an interesting and active field of research in which theoretical information on the microphysical domain systems may help to understand and rationalize the wealth of experimental information. This can also be the initial step in the study of more complex mixtures with higher amounts of water or variable proportions of their constituents. This kind of calculations have been successfully performed in the past[4]. We present here our results on the structure and spectroscopic and thermodynamic properties of the energy-lowest lying structures among those thermodynamically stable formed by linking the acids plus water. The calculations have been carried out by means of DFT methods (in particular the successful B3LYP) using different basis sets that contain appropriate sets of polarization and diffuse functions up to quadruple-Z quality (Dunninǵs aug-cc-pVQZ). Careful assessment of the dependability of the methodology used has been carried out. This work has been supported by the Spanish Ministry of Education, Projects FIS2007-61686 and CTQ2008-02578/BQU References: [1] Carslaw, K. S. et al.: Geophys. Res. Lett. 21, 2479-2482, 1994 [2] Drdla, K. Et al. :Geophys. Res. Lett. 21, 2473-2478, 1994 [3] Tabazadeh, A. et al.: Geophys. Res. Lett 21, 1619-1622, 1994 [4] Escribano, R et al.: J. J. Chem. Phys A 2003, 107, 652.

  12. Avian influenza virus hemagglutinins H2, H4, H8, and H14 support a highly pathogenic phenotype

    PubMed Central

    Veits, Jutta; Weber, Siegfried; Stech, Olga; Breithaupt, Angele; Gräber, Marcus; Gohrbandt, Sandra; Bogs, Jessica; Hundt, Jana; Teifke, Jens P.; Mettenleiter, Thomas C.; Stech, Jürgen

    2012-01-01

    High-pathogenic avian influenza viruses (HPAIVs) evolve from low-pathogenic precursors specifying the HA serotypes H5 or H7 by acquisition of a polybasic HA cleavage site. As the reason for this serotype restriction has remained unclear, we aimed to distinguish between compatibility of a polybasic cleavage site with H5/H7 HA only and unique predisposition of these two serotypes for insertion mutations. To this end, we introduced a polybasic cleavage site into the HA of several low-pathogenic avian strains with serotypes H1, H2, H3, H4, H6, H8, H10, H11, H14, or H15, and rescued HA reassortants after cotransfection with the genes from either a low-pathogenic H9N2 or high-pathogenic H5N1 strain. Oculonasal inoculation with those reassortants resulted in varying pathogenicity in chicken. Recombinants containing the engineered H2, H4, H8, or H14 in the HPAIV background were lethal and exhibited i.v. pathogenicity indices of 2.79, 2.37, 2.85, and 2.61, respectively, equivalent to naturally occurring H5 or H7 HPAIV. Moreover, the H2, H4, and H8 reassortants were transmitted to some contact chickens. The H2 reassortant gained two mutations in the M2 proton channel gate region, which is affected in some HPAIVs of various origins. Taken together, in the presence of a polybasic HA cleavage site, non-H5/H7 HA can support a highly pathogenic phenotype in the appropriate viral background, indicating requirement for further adaptation. Therefore, the restriction of natural HPAIV to serotypes H5 and H7 is likely a result of their unique predisposition for acquisition of a polybasic HA cleavage site. PMID:22308331

  13. Synthesis and antifungal activity of 2H-1,4-benzoxazin-3(4H)-one derivatives.

    PubMed

    Śmist, Małgorzata; Kwiecień, Halina; Krawczyk, Maria

    2016-06-01

    A series of 2-alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-l) was easily synthesized by two-step process involving O-alkylation of 2-nitrophenols with methyl 2-bromoalkanoates and next "green" catalytic reductive cyclization of the obtained 2-nitro ester intermediates (3a-l). Further, 6,7-dibromo (5a-c) and N-acetyl (6) derivatives were prepared by bromination and acetylation of unsubstituted 2-alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-c). The novel compounds (3a-l, 4d-l, 5a-c and 6) were fully characterized by spectroscopic methods (MS, (1)H and (13)C NMR). 2-Alkyl-2H-1,4-benzoxazin-3(4H)-ones (4a-l, 5a-c and 6) were screened for antifungal activity. Preliminary assays were performed using two methods: in vitro against seven phytopathogenic fungi-Botrytis cinerea, Phythophtora cactorum, Rhizoctonia solani, Phoma betae, Fusarium culmorum, Fusarium oxysporum and Alternaria alternata-and in vivo against barley powdery mildew Blumeria graminis. The tested compounds displayed moderate to good antifungal activity at high concentration (200 mg L(-1)). The most potent compounds were 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a), 2-ethyl-7-fluoro-2H-1,4-benzoxazin-3(4H)-one (4g) and 4-acetyl-2-ethyl-2H-1,4-benzoxazin-3(4H)-one (6), which completely inhibited the mycelial growth of seven agricultural fungi at the concentration of 200 mg L(-1) in the in vitro tests. Moreover, 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a) and 4-acetyl-2-ethyl-2H-1,4-benzoxazin-3(4H)-one (6) were also screened for antifungal activity at concentrations of 100 mg L(-1) and 20 mg L(-1). In the concentration of 100 mg L(-1), the N-acetyl derivative (6) completely inhibited the growth of three strains of fungi (F. culmorum, P. cactorum and R. solani), while 2-ethyl-2H-1,4-benzoxazin-3(4H)-one (4a) completely inhibited only R. solani strain. At the concentration of 20 mg L(-1), compound 6 showed good activity only against P. cactorum strain (72%). PMID:26963527

  14. Synthesis of (3) H, (2) H4 and (14) C-SCH 417690 (Vicriviroc).

    PubMed

    Hesk, D; Borges, S; Hendershot, S; Koharski, D; McNamara, P; Ren, S; Saluja, S; Truong, V; Voronin, K

    2016-05-15

    Vicriviroc or SCH 417690 is a potent and selective antagonist of the CCR5 receptor. CCR5 receptor antagonists have the potential for the treatment of HIV infections. Four distinct isotopically labelled forms of SCH 417690 were synthesized. Low specific activity [(3) H]SCH 417690 was prepared for a preliminary absorption, distribution, metabolism and excretion evaluation of the compound and [(14) C]SCH 417690 for more definitive absorption, distribution, metabolism and excretion work, including an absorption, metabolism and excretion study in man. In addition, high specific activity [(3) H]SCH 417690 was prepared for CCR5 receptor binding work and [(2) H4 ]SCH 417690 was prepared as an internal standard for a liquid chromatography-mass spectrometry bioanalytical method. The paper discusses the synthesis of four isotopically labelled forms of SCH 417690. PMID:26991320

  15. Characterization Results for the 2014 HTF 3H & 2H Evaporator Overhead Samples

    SciTech Connect

    Washington, A.

    2015-05-11

    This report tabulates the radiochemical analysis of the 3H and 2H evaporator overhead samples for 137Cs, 90Sr, and 129I to meet the requirements in the Effluent Treatment Project (ETP) Waste Acceptance Criteria (WAC) (rev. 6). This report identifies the sample receipt date, preparation method, and analysis performed in the accumulation of the listed values. All data was found to be within the ETP WAC (rev. 6) specification for the Waste Water Collection Tanks (WWCT).

  16. Cometary implications of recent laboratory experiments on the photochemistry of the C2H and C3H2 radicals

    NASA Technical Reports Server (NTRS)

    Jackson, William M.; Bao, Yihan; Urdahl, Randall S.; Song, Xueyu; Gosine, Jai; Lu, Chi

    1992-01-01

    Recent laboratory results on the photodissociation of the C2H and C3H2 radicals are described. These studies show that the C2 and C3 radicals are produced by the 193 nm photolysis of the C2H and C3H2 radicals, respectively. The quantum state distributions that were determined for the C2 radicals put certain constraints on the initial conditions for any models of the observed C2 cometary spectra. Experimental observations of C2 formed by the 212.8 nm photolysis of C2H are used to calculate a range of photochemical lifetimes for the C2H radical.

  17. Direct N2H4/H2O2 Fuel Cells Powered by Nanoporous Gold Leaves

    PubMed Central

    Yan, Xiuling; Meng, Fanhui; Xie, Yun; Liu, Jianguo; Ding, Yi

    2012-01-01

    Dealloyed nanoporous gold leaves (NPGLs) are found to exhibit high electrocatalytic properties toward both hydrazine (N2H4) oxidation and hydrogen peroxide (H2O2) reduction. This observation allows the implementation of a direct hydrazine-hydrogen peroxide fuel cell (DHHPFC) based on these novel porous membrane catalysts. The effects of fuel and oxidizer flow rate, concentration and cell temperature on the performance of DHHPFC are systematically investigated. With a loading of ~0.1 mg cm−2 Au on each side, an open circuit voltage (OCV) of 1.2 V is obtained at 80°C with a maximum power density 195 mW cm−2, which is 22 times higher than that of commercial Pt/C electrocatalyst at the same noble metal loading. NPGLs thus hold great potential as effective and stable electrocatalysts for DHHPFCs. PMID:23230507

  18. Infrared band extinctions and complex refractive indices of crystalline C2H2 and C4H2

    NASA Astrophysics Data System (ADS)

    Khanna, R. K.; Ospina, Mario J.; Zhao, Guizhi

    1988-03-01

    Thermal IR absorption intensities are obtained for thin films of crystalline C2H2 and C4H2 at 70 K, and their n and k complex refractive indices are ascertained by separating true film absorption from interface reflection on the basis of an analysis of the transmission spectrum ratio for two sample thicknesses. This method significantly simplifies the n and k iteration process. The n and k values determined in the laboratory will in most cases reproduce a given sample thickness' observed transmission to within + or - 5 percent.

  19. Infrared band extinctions and complex refractive indices of crystalline C2H2 and C4H2

    NASA Technical Reports Server (NTRS)

    Khanna, R. K.; Ospina, Mario J.; Zhao, Guizhi

    1988-01-01

    Thermal IR absorption intensities are obtained for thin films of crystalline C2H2 and C4H2 at 70 K, and their n and k complex refractive indices are ascertained by separating true film absorption from interface reflection on the basis of an analysis of the transmission spectrum ratio for two sample thicknesses. This method significantly simplifies the n and k iteration process. The n and k values determined in the laboratory will in most cases reproduce a given sample thickness' observed transmission to within + or - 5 percent.

  20. Chemical destruction of CH3I, C2H5I, 1-C3H7I, and 2-C3H7I in saltwater

    NASA Astrophysics Data System (ADS)

    Jones, Charlotte E.; Carpenter, Lucy J.

    2007-07-01

    Destruction of volatile iodocarbons in the oceans can potentially play an important role in determining the predominant chemical forms of iodine emitted to the atmosphere. Here we report chlorination and hydrolysis removal rates for CH3I, C2H5I, 1-C3H7I, and 2-C3H7I relevant to oceanic conditions. We have used these rates to calculate oceanic lifetimes for each iodocarbon with respect to total chemical destruction, as a function of seawater temperature. The resulting lifetimes are compared to typical iodocarbon oceanic residence times with respect to volatilization to the MBL. The rate of destruction of 2-C3H7I is much more rapid than chemical removal of the primary alkyl iodides, potentially explaining previous observations of lower 2-C3H7I concentrations in seawater compared to 1-C3H7I. Finally, in light of these results, we briefly discuss the potential impact of rising global seawater temperatures on oceanic iodocarbon concentrations.

  1. Theoretical study of radiative electron attachment to CN, C{sub 2}H, and C{sub 4}H radicals

    SciTech Connect

    Douguet, Nicolas; Fonseca dos Santos, S.; Orel, Ann E.; Raoult, Maurice; Dulieu, Olivier

    2015-06-21

    A first-principle theoretical approach to study the process of radiative electron attachment is developed and applied to the negative molecular ions CN{sup −}, C{sub 4}H{sup −}, and C{sub 2}H{sup −}. Among these anions, the first two have already been observed in the interstellar space. Cross sections and rate coefficients for formation of these ions by direct radiative electron attachment to the corresponding neutral radicals are calculated. For the CN molecule, we also considered the indirect pathway, in which the electron is initially captured through non-Born-Oppenheimer coupling into a vibrationally resonant excited state of the anion, which then stabilizes by radiative decay. We have shown that the contribution of the indirect pathway to the formation of CN{sup −} is negligible in comparison to the direct mechanism. The obtained rate coefficients for the direct mechanism at 30 K are 7 × 10{sup −16} cm{sup 3}/s for CN{sup −}, 7 × 10{sup −17} cm{sup 3}/s for C{sub 2}H{sup −}, and 2 × 10{sup −16} cm{sup 3}/s for C{sub 4}H{sup −}. These rates weakly depend on temperature between 10 K and 100 K. The validity of our calculations is verified by comparing the present theoretical results with data from recent photodetachment experiments.

  2. {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions at sub-coulomb energies

    SciTech Connect

    Tumino, A.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Sparta, R.; Aliotta, M.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Mrazek, J.; Pizzone, R. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.

    2012-11-20

    The {sup 2}H({sup 3}He,p{sup 3}H){sup 1}H and {sup 2}H({sup 3}He,n{sup 3}He){sup 1}H processes have been measured in quasi free kinematics to investigate for the first time the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions by means of the Trojan Horse Method. The {sup 3}He+d experiment was performed at 18 MeV, corresponding the a d-d energy range from 1.5 MeV down to 2 keV. This range overlaps with the relevant region for Standard Big Bang Nucleosynthesis as well as with the thermal energies of future fusion reactors and deuterium burning in the Pre Main Sequence phase of stellar evolution. This is the first pioneering experiment in quasi free regime where the charged spectator is detected. Both the energy dependence and the absolute value of the bare nucleus S(E) factors have been extracted for the first time. They deviate by more than 15% from available direct data with new S(0) values of 57.4{+-}1.8 MeVb for {sup 3}H+p and 60.1{+-}1.9 MeVb for {sup 3}He+n. None of the existing fitting curves is able to provide the correct slope of the new data in the full range, thus calling for a revision of the theoretical description. This has consequences in the calculation of the reaction rates with more than a 25% increase at the temperatures of future fusion reactors.

  3. New determination of the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reaction rates at astrophysical energies

    SciTech Connect

    Tumino, A.; Spartà, R.; Spitaleri, C.; Pizzone, R. G.; La Cognata, M.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Mukhamedzhanov, A. M.; Typel, S.; Tognelli, E.; Degl'Innocenti, S.; Prada Moroni, P. G.; Burjan, V.; Kroha, V.; Hons, Z.; Mrazek, J.; Piskor, S.; Lamia, L.

    2014-04-20

    The cross sections of the {sup 2}H(d,p){sup 3}H and {sup 2}H(d,n){sup 3}He reactions have been measured via the Trojan Horse method applied to the quasi-free {sup 2}H({sup 3}He,p {sup 3}H){sup 1}H and {sup 2}H({sup 3}He,n {sup 3}He){sup 1}H processes at 18 MeV off the proton in {sup 3}He. For the first time, the bare nucleus S(E) factors have been determined from 1.5 MeV, across the relevant region for standard Big Bang nucleosynthesis, down to the thermal energies of deuterium burning in the pre-main-sequence (PMS) phase of stellar evolution, as well as of future fusion reactors. Both the energy dependence and the absolute value of the S(E) factors deviate by more than 15% from the available direct data and existing fitting curves, with substantial variations in the electron screening by more than 50%. As a consequence, the reaction rates for astrophysics experience relevant changes, with a maximum increase of up to 20% at the temperatures of the PMS phase. From a recent primordial abundance sensitivity study, it turns out that the {sup 2}H(d,n){sup 3}He reaction is quite influential on {sup 7}Li, and the present change in the reaction rate leads to a decrease in its abundance by up to 10%. The present reaction rates have also been included in an updated version of the FRANEC evolutionary code to analyze their influence on the central deuterium abundance in PMS stars with different masses. The largest variation of about 10%-15% pertains to young stars (≤1 Myr) with masses ≥1 M {sub ☉}.

  4. New Determination of the 2H(d,p)3H and 2H(d,n)3He Reaction Rates at Astrophysical Energies

    NASA Astrophysics Data System (ADS)

    Tumino, A.; Spartà, R.; Spitaleri, C.; Mukhamedzhanov, A. M.; Typel, S.; Pizzone, R. G.; Tognelli, E.; Degl'Innocenti, S.; Burjan, V.; Kroha, V.; Hons, Z.; La Cognata, M.; Lamia, L.; Mrazek, J.; Piskor, S.; Prada Moroni, P. G.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.

    2014-04-01

    The cross sections of the 2H(d,p)3H and 2H(d,n)3He reactions have been measured via the Trojan Horse method applied to the quasi-free 2H(3He,p 3H)1H and 2H(3He,n 3He)1H processes at 18 MeV off the proton in 3He. For the first time, the bare nucleus S(E) factors have been determined from 1.5 MeV, across the relevant region for standard Big Bang nucleosynthesis, down to the thermal energies of deuterium burning in the pre-main-sequence (PMS) phase of stellar evolution, as well as of future fusion reactors. Both the energy dependence and the absolute value of the S(E) factors deviate by more than 15% from the available direct data and existing fitting curves, with substantial variations in the electron screening by more than 50%. As a consequence, the reaction rates for astrophysics experience relevant changes, with a maximum increase of up to 20% at the temperatures of the PMS phase. From a recent primordial abundance sensitivity study, it turns out that the 2H(d,n)3He reaction is quite influential on 7Li, and the present change in the reaction rate leads to a decrease in its abundance by up to 10%. The present reaction rates have also been included in an updated version of the FRANEC evolutionary code to analyze their influence on the central deuterium abundance in PMS stars with different masses. The largest variation of about 10%-15% pertains to young stars (<=1 Myr) with masses >=1 M ⊙.

  5. The Organocatalytic Approach to Enantiopure 2H- and 3H-Pyrroles: Inhibitors of the Hedgehog Signaling Pathway.

    PubMed

    Kötzner, Lisa; Leutzsch, Markus; Sievers, Sonja; Patil, Sumersing; Waldmann, Herbert; Zheng, Yiying; Thiel, Walter; List, Benjamin

    2016-06-27

    A divergent approach to enantioenriched 2H- and 3H-pyrroles catalyzed by a spirocyclic phosphoric acid is reported that makes use of a Fischer-type indolization and a [1,5]-alkyl shift. Catalyzed by the chiral phosphoric acid STRIP, good to excellent yields and enantioselectivities could be obtained. Remarkably, biological evaluation reveals one of these novel 2H-pyrroles to be a potent but nontoxic inhibitor of the Hedgehog signaling pathway by binding to the Smoothened protein. PMID:27239757

  6. Trojan Horse particle invariance for 2H(d,p)3H reaction: a detailed study

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Rinollo, A.; Spartá, R.; Tumino, A.

    2014-03-01

    In the last decades the Trojan Horse method has played a crucial role for the measurement of several charged particle induced reactions cross sections of astrophysical interest. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary d(d,p)t reaction was therefore tested using the quasi free 2H(6Li, pt)4He and 2H(3He,pt)H reactions after 6Li and 3He break-up, respectively. The astrophysical S(E)-factor for the d(d,p)t binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present case.

  7. Synthesis of 2H-Azirines by Iridium-Catalyzed Decarboxylative Ring Contraction of Isoxazol-5(4H)-ones.

    PubMed

    Okamoto, Kazuhiro; Shimbayashi, Takuya; Yoshida, Masato; Nanya, Atsushi; Ohe, Kouichi

    2016-06-13

    A phosphine-free iridium-catalyzed reaction of isoxazol-5(4H)-ones (isoxazolones) has been developed, and affords 2H-azirines through decarboxylation and ring contraction. This method provides an efficient and environmentally benign protocol which could replace the conventional approaches used to synthesize 2H-azirines. PMID:27125870

  8. Measurement of the 2H(d ,p ) 3H reaction at astrophysical energies via the Trojan-horse method

    NASA Astrophysics Data System (ADS)

    Li, Chengbo; Wen, Qungang; Fu, Yuanyong; Zhou, Jing; Zhou, Shuhua; Meng, Qiuying; Spitaleri, C.; Tumino, A.; Pizzone, R. G.; Lamia, L.

    2015-08-01

    The study of the 2H(d ,p ) 3H reaction is very important for the nucleosynthesis in both the standard Big Bang and stellar evolution, as well as for the future fusion reactor's planning of energy production. The 2H(d ,p ) 3H bare nucleus astrophysical S (E ) factor has been measured indirectly at energies from about 400 keV down to several keV by means of the Trojan-horse method applied to the quasifree process 2H(6Li ,p t ) 4He induced at a lithium beam energy of 9.5 MeV, which is closer to the zero-quasifree-energy point. An accurate analysis leads to the determination of the Sbare(0 ) =56.7 ±2.0 keV b and of the corresponding electron screening potential Ue=13.2 ±4.3 eV. In addition, this work gives an updated test for the Trojan-horse nucleus invariance by comparing with previous indirect investigations using the 3He=(d +p ) breakup.

  9. Synthesis and Antibacterial Activity of 3-(Substituted)-2-(4-oxo-2-phenylquinazolin-3(4H)-ylamino)quinazolin-4(3H)-one.

    PubMed

    Appani, Ramgopal; Bhukya, Baburao; Gangarapu, Kiran

    2016-01-01

    A series of novel 3-(substituted)-2-(substituted quinazolinylamino)quinazolin-4(3H)-ones were synthesized by the reaction of 3-(substituted)-2-hydrazino-quinazoline-4(3H)-ones with 2-phenyl-3,1-benzoxazin-4-one. The starting materials 3-(substituted)-2-hydrazino-quinazolin-4(3H)-ones were synthesized from various primary amines by a multistep synthesis. All the title compounds were tested for their antibacterial activity using ciprofloxacin as reference standard. Compounds 3-(4-fluorophenyl)-2-(4-oxo-2-phenylquinazolin-3(4H)-ylamino)quinazolin-4(3H)-one (9a) and 3-(4-chlorophenyl)-2-(4-oxo-2-phenylquinazolin-3(4H)-ylamino)quinazolin-4(3H)-one (9h) emerged as the most active compounds of the series. These compounds have shown most potent antibacterial activity against the tested organisms of Proteus vulgaris and Bacillus subtilis having zone of inhibition values of 1.1 cm and 1.4 cm for compound 9a 1.2 cm and 1.0 cm for compound 9h, respectively. PMID:27190676

  10. Synthesis and Antibacterial Activity of 3-(Substituted)-2-(4-oxo-2-phenylquinazolin-3(4H)-ylamino)quinazolin-4(3H)-one

    PubMed Central

    Appani, Ramgopal; Bhukya, Baburao; Gangarapu, Kiran

    2016-01-01

    A series of novel 3-(substituted)-2-(substituted quinazolinylamino)quinazolin-4(3H)-ones were synthesized by the reaction of 3-(substituted)-2-hydrazino-quinazoline-4(3H)-ones with 2-phenyl-3,1-benzoxazin-4-one. The starting materials 3-(substituted)-2-hydrazino-quinazolin-4(3H)-ones were synthesized from various primary amines by a multistep synthesis. All the title compounds were tested for their antibacterial activity using ciprofloxacin as reference standard. Compounds 3-(4-fluorophenyl)-2-(4-oxo-2-phenylquinazolin-3(4H)-ylamino)quinazolin-4(3H)-one (9a) and 3-(4-chlorophenyl)-2-(4-oxo-2-phenylquinazolin-3(4H)-ylamino)quinazolin-4(3H)-one (9h) emerged as the most active compounds of the series. These compounds have shown most potent antibacterial activity against the tested organisms of Proteus vulgaris and Bacillus subtilis having zone of inhibition values of 1.1 cm and 1.4 cm for compound 9a 1.2 cm and 1.0 cm for compound 9h, respectively. PMID:27190676

  11. Homocatenation of aluminum: alkane-like structures of Li2Al2H6 and Li3Al3H8.

    PubMed

    Gish, J Tyler; Popov, Ivan A; Boldyrev, Alexander I

    2015-03-27

    A new class of aluminum homocatenated compounds (LinAlnH2n+2) is proposed based on quantum chemical calculations. In these compounds, Al abstracts an electron from Li, becoming valence isoelectronic with C, Si, and Ge, thus mimicking respective structural features of Group 14 hydrides. Using the Coalescence Kick search program coupled with density functional theory calculations, we investigated the potential energy surfaces of Li2Al2 H6 and Li3Al3H6 . Then single-point-energy coupled-cluster calculations were performed for the lowest energy structures found. Indeed, the global minima established for Li2 Al2 H6 and Li3 Al3 H6 contain the Al2 H6(2-) and Al3H6(3-) kernels, which are isostructural with ethane (C2H6), disilane (Si2H6), digermane (Ge2 H6) and propane (C3H8), trisilane (Si3H8), trigermane (Ge3H8) molecules, respectively. Structural, energetic, and electronic characteristics of the Li2 Al2 H6 and Li3 Al3 H8 compounds are presented and the viability of their synthesis is discussed. PMID:25704853

  12. Background considerations for the 2H(7Be,3H)6Be experimental data II: Three-body continuum

    NASA Astrophysics Data System (ADS)

    Chae, K. Y.; Guimarães, V.

    2015-11-01

    The present article reports second background considerations for the experimentally obtained 2H(7Be,3H)6Be differential cross sections. The one-neutron transfer reaction was measured in inverse kinematics by using radioactive 7Be ( t 1/2 = 53.2 days) beams at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory in 2004 in order to search for the resonances in the unbound 6Be nucleus. Resonances in this nucleus would affect the 3He(3He,2 p)4He reaction rate of the proton-proton chain occurring in stars such as our sun. The result shows, however, that the direct transfer to 6Be resonances is not particularly strong compared to other reaction channels that can produce tritons in the exit channels. The goals of the present work is to better understand the cross section data from transfer reaction measurements by adopting background considerations using the three-body continuum.

  13. Meridional Distribution of CH3C2H and C4H2 in Saturn's Stratosphere from CIRS/Cassini Limb and Nadir Observations

    NASA Technical Reports Server (NTRS)

    Guerlet, Sandrine; Fouchet, Thierry; Bezard, Bruno; Moses, Julianne I.; Fletcher, Leigh N.; Simon-Miller, Amy A.; Flasar, F. Michael

    2010-01-01

    Limb and nadir spectra acquired by Cassini/CIRS (Composite InfraRed Spectrometer) are analyzed in order to derive, for the first time, the meridional variations of diacetylene (C4H2) and methylacetylene (CH3C2H) mixing ratios in Saturn's stratosphere, from 5 hPa up to 0.05 hPa and 80 deg S to 45 deg N. We find that the C4H2 and CH3C2H meridional distributions mimic that of acetylene (C2H2), exhibiting small-scale variations that are not present in photochemical model predictions. The most striking feature of the meridional distribution of both molecules is an asymmetry between mid-southern and mid-northern latitudes. The mid-southern latitudes are found depleted in hydrocarbons relative to their northern counterparts. In contrast, photochemical models predict similar abundances at north and south mid-latitudes. We favor a dynamical explanation for this asymmetry, with upwelling in the south and downwelling in the north, the latter coinciding with the region undergoing ring shadowing. The depletion in hydrocarbons at mid-southern latitudes could also result from chemical reactions with oxygen-bearing molecules. Poleward of 60 deg S, at 0.1 and 0.05 hPa, we find that the CH3C2H and C4H2 abundances increase dramatically. This behavior is in sharp contradiction with photochemical model predictions, which exhibit a strong decrease towards the south pole. Several processes could explain our observations, such as subsidence, a large vertical eddy diffusion coefficient at high altitudes, auroral chemistry that enhances CH3C2H and C4H2 production, or shielding from photolysis by aerosols or molecules produced from auroral chemistry. However, problems remain with all these hypotheses, including the lack of similar behavior at lower altitudes. Our derived mean mixing ratios at 0.5 hPa of (2.4 +/- 0.3) 10(exp -10) for C4H2 and of (1.1 +/- 0.3) 10(exp -9) for CH3C2H are compatible with the analysis of global-average ISO observations performed by Moses et al. Finally, we provide

  14. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-1-ol (VMSD1511, LB4927_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-1-ol (VMSD1511, LB4927_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  15. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-2-ol (VMSD1212, LB4923_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-2-ol (VMSD1212, LB4923_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  16. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-2-ol (VMSD1111, LB4915_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-2-ol (VMSD1111, LB4915_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  17. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H8O2 Ethyl ethanoate (VMSD1412, LB4274_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H8O2 Ethyl ethanoate (VMSD1412, LB4274_V)' providing data by calculation of isentropic compressibility from low-pressure density and thermodynamic speed of sound data at variable mole fraction and constant temperature, in the single-phase region(s).

  18. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H9NO N,N-Dimethylethanamide (VMSD1212, LB4263_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H9NO N,N-Dimethylethanamide (VMSD1212, LB4263_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  19. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-1-ol (VMSD1212, LB4919_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-1-ol (VMSD1212, LB4919_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  20. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H8O2 Ethyl ethanoate (VMSD1212, LB4262_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H8O2 Ethyl ethanoate (VMSD1212, LB4262_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  1. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H9NO N,N-Dimethylethanamide (VMSD1111, LB4255_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H9NO N,N-Dimethylethanamide (VMSD1111, LB4255_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  2. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H8O2 Ethyl ethanoate (VMSD1111, LB4252_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H8O2 Ethyl ethanoate (VMSD1111, LB4252_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  3. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H9NO N,N-Dimethylethanamide (VMSD1511, LB4269_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H9NO N,N-Dimethylethanamide (VMSD1511, LB4269_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  4. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-1-ol (VMSD1111, LB4911_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H10O Butan-1-ol (VMSD1111, LB4911_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  5. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H9NO N,N-Dimethylethanamide (VMSD1412, LB4275_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H9NO N,N-Dimethylethanamide (VMSD1412, LB4275_V)' providing data by calculation of isentropic compressibility from low-pressure density and thermodynamic speed of sound data at variable mole fraction and constant temperature, in the single-phase region(s).

  6. Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H8O2 Ethyl ethanoate (VMSD1511, LB4268_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C4H8O2 Ethyl ethanoate (VMSD1511, LB4268_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  7. 2H,3H-Decafluoropentane-Based Nanodroplets: New Perspectives for Oxygen Delivery to Hypoxic Cutaneous Tissues

    PubMed Central

    Jose, Jithin; Khadjavi, Amina; Cavallo, Federica; Quaglino, Elena; Panariti, Alice; Rivolta, Ilaria; Benintende, Emilio; Varetto, Gianfranco; Argenziano, Monica; Troia, Adriano; Cavalli, Roberta; Guiot, Caterina

    2015-01-01

    Perfluoropentane (PFP)-based oxygen-loaded nanobubbles (OLNBs) were previously proposed as adjuvant therapeutic tools for pathologies of different etiology sharing hypoxia as a common feature, including cancer, infection, and autoimmunity. Here we introduce a new platform of oxygen nanocarriers, based on 2H,3H-decafluoropentane (DFP) as core fluorocarbon. These new nanocarriers have been named oxygen-loaded nanodroplets (OLNDs) since DFP is liquid at body temperature, unlike gaseous PFP. Dextran-shelled OLNDs, available either in liquid or gel formulations, display spherical morphology, ~600 nm diameters, anionic charge, good oxygen carrying capacity, and no toxic effects on human keratinocytes after cell internalization. In vitro OLNDs result more effective in releasing oxygen to hypoxic environments than former OLNBs, as demonstrated by analysis through oxymetry. In vivo, OLNDs effectively enhance oxy-hemoglobin levels, as emerged from investigation by photoacoustic imaging. Interestingly, ultrasound (US) treatment further improves transdermal oxygen release from OLNDs. Taken together, these data suggest that US-activated, DFP-based OLNDs might be innovative, suitable and cost-effective devices to topically treat hypoxia-associated pathologies of the cutaneous tissues. PMID:25781463

  8. 2H,3H-decafluoropentane-based nanodroplets: new perspectives for oxygen delivery to hypoxic cutaneous tissues.

    PubMed

    Prato, Mauro; Magnetto, Chiara; Jose, Jithin; Khadjavi, Amina; Cavallo, Federica; Quaglino, Elena; Panariti, Alice; Rivolta, Ilaria; Benintende, Emilio; Varetto, Gianfranco; Argenziano, Monica; Troia, Adriano; Cavalli, Roberta; Guiot, Caterina

    2015-01-01

    Perfluoropentane (PFP)-based oxygen-loaded nanobubbles (OLNBs) were previously proposed as adjuvant therapeutic tools for pathologies of different etiology sharing hypoxia as a common feature, including cancer, infection, and autoimmunity. Here we introduce a new platform of oxygen nanocarriers, based on 2H,3H-decafluoropentane (DFP) as core fluorocarbon. These new nanocarriers have been named oxygen-loaded nanodroplets (OLNDs) since DFP is liquid at body temperature, unlike gaseous PFP. Dextran-shelled OLNDs, available either in liquid or gel formulations, display spherical morphology, ~600 nm diameters, anionic charge, good oxygen carrying capacity, and no toxic effects on human keratinocytes after cell internalization. In vitro OLNDs result more effective in releasing oxygen to hypoxic environments than former OLNBs, as demonstrated by analysis through oxymetry. In vivo, OLNDs effectively enhance oxy-hemoglobin levels, as emerged from investigation by photoacoustic imaging. Interestingly, ultrasound (US) treatment further improves transdermal oxygen release from OLNDs. Taken together, these data suggest that US-activated, DFP-based OLNDs might be innovative, suitable and cost-effective devices to topically treat hypoxia-associated pathologies of the cutaneous tissues. PMID:25781463

  9. Fabrication of Indocyanine Green and 2H, 3H-perfluoropentane loaded microbubbles for fluorescence and ultrasound imaging

    NASA Astrophysics Data System (ADS)

    He, Yutong; Wu, Qiang; Ma, Rong; Chang, Shufang; Shao, Pengfei; Xu, Ronald

    2016-03-01

    As a near-infrared (NIR) fluorescence dye, Indocyanine Green (ICG) has not gained broader clinical applications, owing to its multiple limitations such as concentration-dependent aggregation, low fluorescence quantum yield, poor physicochemical stability and rapid elimination from the body. In the meanwhile, 2H,3H-perfluoropentane (H-PFP) has been widely studied in ultrasound imaging as a vehicle for targeted delivery of contrast agents and drugs. We synthesized a novel dual-modal fluorescence and ultrasound contrast agent by encapsulating ICG and H-PFP in lipid microbubbles using a liquid-driven coaxial flow focusing (LDCFF) process. Uniform microbubbles with the sizes ranging from 1-10um and great ICG loading efficiency was achieved by this method. Our benchtop experiments showed that ICG/H-PFP microbubbles exhibited less aggregation, increased fluorescence intensity and more stable photostability compared to free ICG aqueous solution. Our phantom experiments demonstrated that ICG/H-PFP microbubbles enhanced the imaging contrasts in fluorescence imaging and ultrasonography. Our animal experiments indicated that ICG/H-PFP microbubbles extended the ICG life time and facilitated dual mode fluorescence and ultrasound imaging in vivo.

  10. The {sup 2}H(d,p){sup 3}H Reaction At Astrophysical Energies Studied Via The Trojan Horse Method And Pole Approximation Validity Test

    SciTech Connect

    Sparta, R.; Pizzone, R. G.; Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Aliotta, M.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Kiss, G.; McCleskey, M.; Trache, L.

    2010-03-01

    In order to understand primordial and stellar nucleosynthesis, we have studied {sup 2}H(d,p){sup 3}H reaction at 0, 4 MeV down to astrophysical energies. Knowledge of this S-factor is interesting also to plan reactions for fusion reactors to produce energy. {sup 2}H(d,p){sup 3}H has been studied through the Trojan Horse Method applied to the three-body reaction {sup 2}H({sup 3}He,pt)H, at a beam energy of 17 MeV. Once protons and tritons are detected in coincidence and the quasi-free events are selected, the obtained S-factor has been compared with direct reactions results. Such data are in agreement with the direct ones, and a pole invariance test has been obtained comparing the present result with another {sup 2}H(d,p){sup 3}H THM one, performed with a different spectator particle (see fig. 1).

  11. Structure, ferroelectric ordering, and semiempirical quantum calculations of lanthanide based metal-organic framework: [Nd(C4H5O6)(C4H4O6)][3H2O

    NASA Astrophysics Data System (ADS)

    Ahmad, Bhat Zahoor; Want, Basharat

    2016-04-01

    We investigate the structure and ferroelectric behavior of a lanthanide based metal-organic framework (MOF), [Nd(C4H5O6)(C4H4O6)][3H2O]. X-ray crystal structure analyses reveal that it crystallizes in the P41212 space group with Nd centres, coordinated by nine oxygen atoms, forming a distorted capped square antiprismatic geometry. The molecules, bridged by tartrate ligands, form a 2D chiral structure. The 2D sheets are further linked into a 3D porous framework via strong hydrogen-bonding scheme (O-H…O ≈ 2.113 Å). Dielectric studies reveal two anomalies at 295 K and 185 K. The former is a paraelectric-ferroelectric transition, and the later is attributed to the freezing down of the motion of the hydroxyl groups. The phase transition is of second order, and the spontaneous polarization in low temperature phase is attributed to the ordering of protons of hydroxyl groups. The dielectric nonlinearity parameters have been calculated using Landau- Devonshire phenomenological theory. In addition, the most recent semiempirical models, Sparkle/PM7, Sparkle/RM1, and Sparkle/AM1, are tested on the present system to assay the accuracy of semiempirical quantum approaches to predict the geometries of solid MOFs. Our results show that Sparkle/PM7 model is the most accurate to predict the unit cell structure and coordination polyhedron geometry. The semiempirical methods are also used to calculate different ground state molecular properties.

  12. 6-Hydroxy-1,2,4-triazine-3,5(2H,4H)-dione Derivatives as Novel d-Amino Acid Oxidase Inhibitors

    PubMed Central

    2015-01-01

    A series of 2-substituted 6-hydroxy-1,2,4-triazine-3,5(2H,4H)-dione derivatives were synthesized as inhibitors of d-amino acid oxidase (DAAO). Many compounds in this series were found to be potent DAAO inhibitors, with IC50 values in the double-digit nanomolar range. The 6-hydroxy-1,2,4-triazine-3,5(2H,4H)-dione pharmacophore appears metabolically resistant to O-glucuronidation unlike other structurally related DAAO inhibitors. Among them, 6-hydroxy-2-(naphthalen-1-ylmethyl)-1,2,4-triazine-3,5(2H,4H)-dione 11h was found to be selective over a number of targets and orally available in mice. Furthermore, oral coadministration of d-serine with 11h enhanced the plasma levels of d-serine in mice compared to the oral administration of d-serine alone, demonstrating its ability to serve as a pharmacoenhancer of d-serine. PMID:26309148

  13. Cascade alkylarylation of substituted N-allylbenzamides for the construction of dihydroisoquinolin-1(2H)-ones and isoquinoline-1,3(2H,4H)-diones

    PubMed Central

    Qian, Ping; Du, Bingnan; Jiao, Wei; Mei, Haibo

    2016-01-01

    Summary An oxidative reaction for the synthesis of 4-alkyl-substituted dihydroisoquinolin-1(2H)-ones with N-allylbenzamide derivatives as starting materials has been developed. The radical alkylarylation reaction proceeds through a sequence of alkylation and intramolecular cyclization. The substituent on the C–C double bond was found to play a key role for the progress of the reaction to give the expected products with good chemical yields. Additionally, N-methacryloylbenzamides were also suitable substrates for the current reaction and provided the alkyl-substituted isoquinoline-1,3(2H,4H)-diones in good yield. PMID:26977189

  14. Conversion of erythro-D-sphinganine to its (1-/sup 2/H/sub 1/) and (1-/sup 3/H/sub 1/) derivatives

    SciTech Connect

    Crossman, M.W.; Hirschberg, C.B.

    1984-07-01

    A convenient chemical synthesis of erythro-D-(1-2H1) sphinganine and erythro-D-(1-3H1)sphinganine is described. The approach utilizes a stereospecific starting material (natural sphinganine prepared from bovine brain sphingomyelin) and applies a sequence of selective protection of functional groups yielding 2-acetamido-3-O-benzoyloctadecan-1-ol. Oxidation of the primary alcohol to an aldehyde followed by NaB2H4 or NaB3H4 reduction and hydrolysis of the protective groups yields erythro-D-(1-2H1)sphinganine or erythro-D-(1-3H1)sphinganine. The synthetic intermediates and isotopically labeled sphinganines are characterized by infrared analysis, 1H-nuclear magnetic resonance, optical rotation, and gas-liquid radiochromatographic and mass spectral fragmentation analyses. The (1-2H1) and (1-3H1) derivatives were obtained with overall yields (and isotope enrichments) of 11% (min. 84 mol% 2H1) and 8% (60 mCi/mmol), respectively.

  15. Rhodium-catalyzed cascade oxidative annulation leading to substituted naphtho[1,8-bc]pyrans by sequential cleavage of C(sp2)-H/C(sp3)-H and C(sp2)-H/O-H bonds.

    PubMed

    Tan, Xing; Liu, Bingxian; Li, Xiangyu; Li, Bin; Xu, Shansheng; Song, Haibin; Wang, Baiquan

    2012-10-01

    The cascade oxidative annulation reactions of benzoylacetonitrile with internal alkynes proceed efficiently in the presence of a rhodium catalyst and a copper oxidant to give substituted naphtho[1,8-bc]pyrans by sequential cleavage of C(sp(2))-H/C(sp(3))-H and C(sp(2))-H/O-H bonds. These cascade reactions are highly regioselective with unsymmetrical alkynes. Experiments reveal that the first-step reaction proceeds by sequential cleavage of C(sp(2))-H/C(sp(3))-H bonds and annulation with alkynes, leading to 1-naphthols as the intermediate products. Subsequently, 1-naphthols react with alkynes by cleavage of C(sp(2))-H/O-H bonds, affording the 1:2 coupling products. Moreover, some of the naphtho[1,8-bc]pyran products exhibit intense fluorescence in the solid state. PMID:22989331

  16. Updated evidence of the Trojan horse particle invariance for the 2H(d,p)3H reaction

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Rinollo, A.; Spartá, R.; Tumino, A.

    2013-02-01

    The Trojan horse nucleus invariance for the binary d(d,p)t reaction was tested by means of an experiment using the quasifree 2H(6Li,pt)4He and 2H(3He,pt)H reactions after 6Li and 3He breakup, respectively. The astrophysical S(E) factor for the d(d,p)t binary process was extracted from the present data in the framework of the plane wave approximation applied to the two different breakup schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus also for the present case.

  17. Synthesis and Application of Tetrahydro-2H-fluorenes by a Pd(0)-Catalyzed Benzylic C(sp(3) )-H Functionalization.

    PubMed

    Suetsugu, Satoshi; Muto, Nobusuke; Horinouchi, Misa; Tsukano, Chihiro; Takemoto, Yoshiji

    2016-06-01

    A new method has been developed for the synthesis of tetrahydro-2H-fluorenes based on a Pd(0)-catalyzed benzylic C(sp(3) )-H functionalization. Importantly, the success of the cyclization step was dependent on there being substituents at the two positions ortho to the benzylic group to avoid an undesired C(sp(2) )-H functionalization. This method was subsequently used to prepare the right-hand fragment of the hexacyclic triterpenoid benzohopanes, and therefore represents a powerful tool for the construction of the related compounds. PMID:27124498

  18. Anthranil: An Aminating Reagent Leading to Bifunctionality for Both C(sp(3) )-H and C(sp(2) )-H under Rhodium(III) Catalysis.

    PubMed

    Yu, Songjie; Tang, Guodong; Li, Yingzi; Zhou, Xukai; Lan, Yu; Li, Xingwei

    2016-07-18

    Previous direct C-H nitrogenation suffered from simple amidation/amination with limited atom-economy and is mostly limited to C(sp(2) )-H substrates. In this work, anthranil was designed as a novel bifunctional aminating reagent for both C(sp(2) )-H and C(sp(3) )-H bonds under rhodium(III) catalysis, thus affording a nucleophilic aniline tethered to an electrophilic carbonyl. A tridendate rhodium(III) complex has been isolated as the resting state of the catalyst, and DFT studies established the intermediacy of a nitrene species. PMID:27121133

  19. Steric course of the rhodium-catalyzed decarbonylation of chiral 4-methyl-[1-3H,2-2H1]pentanal.

    PubMed

    Otsuka, H; Floss, H G

    1987-04-01

    (R)- and (S)-4-methyl-[1-3H,2-2H1]pentanal were prepared from L- and D-leucine via leucic acid and (S)- and (R)-4-methyl-[2-2H1]pentanoic acid. Decarbonylation of these samples with tris-(triphenylphosphine)rhodium chloride followed by Kuhn-Roth oxidation of the resulting 2-methylbutane gave chiral acetic acid of 35% e.e. S and 31% e.e. R configuration, respectively. The decarbonylation reaction thus proceeds with net retention of configuration, possibly accompanied by some racemization. PMID:2955591

  20. Testing the Palma-Clary Reduced Dimensionality Model Using Classical Mechanics on the CH4 + H → CH3 + H2 Reaction.

    PubMed

    Vikár, Anna; Nagy, Tibor; Lendvay, György

    2016-07-14

    Application of exact quantum scattering methods in theoretical reaction dynamics of bimolecular reactions is limited by the complexity of the equations of nuclear motion to be solved. Simplification is often achieved by reducing the number of degrees of freedom to be explicitly handled by freezing the less important spectator modes. The reaction cross sections obtained in reduced-dimensionality (RD) quantum scattering methods can be used in the calculation of rate coefficients, but their physical meaning is limited. The accurate test of the performance of a reduced-dimensionality method would be a comparison of the RD cross sections with those obtained in accurate full-dimensional (FD) calculations, which is not feasible because of the lack of complete full-dimensional results. However, classical mechanics allows one to perform reaction dynamics calculations using both the RD and the FD model. In this paper, an RD versus FD comparison is made for the 8-dimensional Palma-Clary model on the example of four isotopologs of the CH4 + H → CH3 + H2 reaction, which has 12 internal dimensions. In the Palma-Clary model, the only restriction is that the methyl group is confined to maintain C3v symmetry. Both RD and FD opacity and excitation functions as well as differential cross sections were calculated using the quasiclassical trajectory method. The initial reactant separation has been handled according to our one-period averaging method [ Nagy et al. J. Chem. Phys. 2016, 144, 014104 ]. The RD and FD excitation functions were found to be close to each other for some isotopologs, but in general, the RD reactivity parameters are lower than the FD reactivity parameters beyond statistical error, and for one of the isotopologs, the deviation is significant. This indicates that the goodness of RD cross sections cannot be taken for granted. PMID:26918703

  1. 2-hydroxyisoquinoline-1,3(2H,4H)-diones (HIDs) as human immunodeficiency virus type 1 integrase inhibitors: Influence of the alkylcarboxamide substitution of position 4.

    PubMed

    Billamboz, Muriel; Suchaud, Virginie; Bailly, Fabrice; Lion, Cedric; Andréola, Marie-Line; Christ, Frauke; Debyser, Zeger; Cotelle, Philippe

    2016-07-19

    Herein, we report further insight into the biological activities displayed by the 2-hydroxyisoquinoline-1,3(2H,4H)-dione (HID) scaffold. Previous studies have evidenced the marked fruitful effect of substitution of this two-metal binding pharmacophore at position 4 by phenyl and benzyl carboxamido chains. Strong human immunodeficiency virus type 1 integrase (HIV-1 IN) inhibitors in the low nanomolar range with micromolar (even down to low nanomolar) anti-HIV activities were obtained. Keeping this essential 4-carboxamido function, we investigated the influence of the replacement of phenyl and benzyl groups by various alkyl chains. This study shows that the recurrent halogenobenzyl pharmacophore found in the INSTIs can be efficiently replaced by an n-alkyl group. With an optimal length of six carbons, we observed a biological profile and a high barrier to resistance equivalent to those of a previously reported hit compound bearing a 4-fluorobenzyl group. PMID:27105029

  2. The protection of high efficiency solar thermal collectors using the ternary mixture MnSO4-H2O-C2H6O2

    NASA Astrophysics Data System (ADS)

    Stephens, R. B.; Whitcomb, J.

    1980-10-01

    The solubility of MnSO4 in water declines as the temperature of the solution is raised. This effect can be used to coat the absorber plate of a solar collector with a layer of fine white crystals which scatter light away from the absorber if it exceeds a predetermined temperature. The solubility limits of the ternary system MnSO4-H2O-C2H6O2 show that ethylene glycol added to the mix provided adequate antifreeze protection and also increased the coating ability of the solution. It was also found that the kinetics of nucleation and crystallization for this system are so slow that it will remain indefinitely in the supersaturated state; crystals only precipitate upon the initiation of boiling.

  3. Synthesis of 2H-1,3-benzoxazin-4(3H)-one derivatives containing indole moiety: their in vitro evaluation against PDE4B.

    PubMed

    Rao, Raja Mohan; Luther, Bethala Jawahar; Rani, Chekuri Sharmila; Suresh, Namburi; Kapavarapu, Ravikumar; Parsa, Kishore V L; Rao, Mandava V Basaveswara; Pal, Manojit

    2014-02-15

    A number of 2H-1,3-benzoxazin-4(3H)-one derivatives containing indole or benzofuran moieties were synthesized by using Pd/C-Cu mediated coupling-cyclization strategy as a key step. The o-iodoanilides or o-iodophenol were coupled with 3-{2-(prop-2-ynyloxy)ethyl}-2H-benzo[e][1,3]oxazin-4(3H)-one using 10%Pd/C-CuI-PPh3 as a catalyst system and Et3N as a base to give the target compounds. All the synthesized compounds were tested for their PDE4B inhibitory potential in vitro using a cell based cAMP reporter assay. Some of them showed fold increase of the cAMP level when tested at 30 μM. A representative compound showed encouraging PDE4B inhibitory properties that were supported by its docking results. PMID:24440301

  4. Rh(III)-Catalyzed Oxidative Annulation Leading to Substituted Indolizines by Cleavage of C(sp(2))-H/C(sp(3))-H Bonds.

    PubMed

    Shen, Bingxue; Li, Bin; Wang, Baiquan

    2016-06-17

    Rhodium(III)-catalyzed oxidative annulation reactions of pyridinium trifluoromethanesulfonate salts with alkynes leading to substituted indolizines by cleavage of C(sp(2))-H/C(sp(3))-H bonds are developed. The starting materials are readily available, and the reactions have a broad substrate scope. This reaction overcomes some drawbacks of the previous indolizine synthetic methods and provides a new efficient route to indolizine derivatives. PMID:27267054

  5. Astrophysical S factors of radiative {sup 3}He{sup 4}He, {sup 3}H{sup 4}He, and {sup 2}H{sup 4}He capture

    SciTech Connect

    Dubovichenko, S. B.

    2010-09-15

    The possibility of describing the astrophysical S factors for radiative {sup 3}He{sup 4}He capture at energies of up to 15 keV and radiative {sup 3}H{sup 4}He and {sup 2}H{sup 4}He capture at energies of up 5 keV is considered on the basis of the potential cluster model involving forbidden states.

  6. Ab initio chemical kinetics for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the related unimolecular decomposition of Si3H8 under a-Si/H CVD conditions.

    PubMed

    Raghunath, P; Lin, M C

    2013-10-24

    The kinetics and mechanisms for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the related unimolecular decomposition of Si3H8 have been investigated by ab initio molecular orbital theory based on the QCISD(T)/CBS//QCISD/6-311++G(d,p) method in conjunction with quantum statistical variational Rice-Ramsperger-Kassel-Marcus (RRKM) calculations. For the barrierless radical association processes, their variational transition states have been characterized by the CASPT2//CASSCF method. The species involved in the study are known to coexist under CVD conditions. The results show that the association reaction of SiH2 and Si2H6 producing Si3H8 occurs by insertion via its lowest-energy path forming a loose hydrogen-bonding molecular complex with 8.3 kcal/mol binding energy; the reaction is exothermic by 55.0 kcal/mol. The chemically activated Si3H8 adduct can fragment by several paths, producing SiH4 + SiH3SiH (-0.7 kcal/mol), Si(SiH3)2 + H2 (-1.4 kcal/mol), and SiH3SiH2SiH + H2 (-1.4 kcal/mol). The predicted enthalpy changes as given agree well with available thermochemical data. Three other decomposition channels of Si3H8 occurring by Si-H or Si-Si breaking were found to be highly endothermic, and the reactions take place without a well-defined barrier. The heats of formation of Si3H8, SiH2SiH, Si2H4, i-Si3H7, n-Si3H7, Si(SiH3)2, and SiH3SiH2SiH have been predicted and found to be in close agreement with those available data in the literature. The product branching rate constants for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the thermal unimolecular decomposition of Si3H8 for all low-energy paths have been calculated with multichannel variational RRKM theory covering varying P,T conditions typically employed in PECVD and Cat-CVD processes for hydrogenated amorphous silicon (a-Si/H) film growth. The results were also found to be in good agreement with available kinetic data. Our kinetic results may be employed to model and control very large-area a-Si/H film growth for a

  7. Reaction of the C2H radical with 1-butyne (C4H6): Low Temperature Kinetics and Isomer-Specific Product Detection

    SciTech Connect

    Soorkia, Satchin; Trevitt, Adam J.; Selby, Talitha M.; Osborn, David L.; Taatjes, Craig A.; Wilson, Kevin R.; Leone, Stephen R.

    2009-12-22

    The rate coefficient for the reaction of the ethynyl radical (C{sub 2}H) with 1-butyne (H-C{triple_bond}C-CH{sub 2}-CH{sub 3}) is measured in a pulsed Laval nozzle apparatus. Ethynyl radicals are formed by laser photolysis of acetylene (C{sub 2}H{sub 2}) at 193 nm and detected via chemiluminescence (C{sub 2}H + O{sub 2} {yields} CH (A{sup 2}{Delta}) + CO{sub 2}). The rate coefficients are measured over the temperature range of 74-295 K. The C{sub 2}H + 1-butyne reaction exhibits no barrier and occurs with rate constants close to the collision limit. The temperature dependent rate coefficients can be fit within experimental uncertainties by the expression k = (2.4 {+-} 0.5) x 10{sup -10} (T/295 K)-(0.04 {+-} 0.03) cm{sup 3} molecule{sup -1}s{sup -1}. Reaction products are detected at room temperature (295 K) and 533 Pa using a Multiplexed Photoionization Mass Spectrometer (MPIMS) coupled to the tunable VUV synchrotron radiation from the Advanced Light Source at the Lawrence Berkeley National Laboratory. Two product channels are identified for this reaction: m/z = 64 (C{sub 5}H{sub 4}) and m/z = 78 (C{sub 6}H{sub 6}) corresponding to the CH{sub 3}- and H-loss channels, respectively. Photoionization efficiency (PIE) curves are used to analyze the isomeric composition of both product channels. The C{sub 5}H{sub 4} products are found to be exclusively linear isomers composed of ethynylallene and methyldiacetylene in a 4:1 ratio. In contrast, the C{sub 6}H{sub 6} product channel includes two cyclic isomers, fulvene 18({+-}5)% and 3,4-dimethylenecyclobut-1-ene 32({+-}8)%, as well as three linear isomers, 2-ethynyl-1,3-butadiene 8({+-}5)%, 3,4-hexadiene-1-yne 28({+-}8)% and 1,3-hexadiyne 14({+-}5)%. Within experimental uncertainties, we do not see appreciable amounts of benzene and an upper limit of 10% is estimated. Diacetylene (C{sub 4}H{sub 2}) formation via the C{sub 2}H{sub 5}-loss channel is also thermodynamically possible but cannot be observed due to experimental

  8. Water - Isotope - Map (δ 18O, δ 2H, 3H) of Austria: Applications, Extremes and Trends

    NASA Astrophysics Data System (ADS)

    Wyhlidal, Stefan; Kralik, Martin; Benischke, Ralf; Leis, Albrecht; Philippitsch, Rudolf

    2016-04-01

    The isotopic ratios of oxygen and hydrogen in water (2H/1H and 18O/16O) are important tools to characterise waters and their cycles. This starts in the atmosphere as rain or snow and continues in surface water and ends in shallow groundwater as well as in deep groundwater. Tritium formed by natural cosmic radiation in the upper atmosphere and in the last century by tests of thermonuclear bombs in the atmosphere, is characterised by its radioactive decay with a half-life of 12.32 years and is an ideal age-marker during the last 60 years. To determine the origin and mean age of waters in many projects concerning water supply, engineering and scientific projects in the last 45 years on more than 1,350 sites, more than 40,000 isotope measurements were performed in Austria. The median value of all sites of oxygen-18 is δ 18O -10.7 ‰ and for hydrogen-2 δ 2H -75 ‰. As the fractionation is mainly temperature dependent the lowest negative values are observed in winter precipitation (oxygen-18 as low as δ 18O -23 ‰) and in springs in the mountain regions (δ 18O -15.1 ‰). In contrast the highest values were observed in summer precipitation (up to δ 18O - 0.5 ‰) and in shallow lakes in the Seewinkel (up to δ 18O + 5 ‰). The isotopic ratios of the Austrian waters are also influenced by the origin of the evaporated water masses. Therefore the precipitation in the region south of the main Alpine crest (East-Tyrol, Carinthia and South-East Styria) is approximately 1 ‰ higher in δ 18O-values than sites at the same altitude in the northern part. This is most probably caused by the stronger influence of precipitation from the mediterranean area. The median value of all 1,120 sampling sites of decay corrected (2015) tritium measurements is 6.2 tritium units (TU). This is somewhat smaller than the median value of all precipitation stations with 7.2 TU. This can be explained by the fact that in most cases in groundwater the median value has been reduced by decay

  9. Sub-Doppler Jet-Cooled Infrared Spectroscopy of ND2H2+ and ND3H+ in the NH Stretch Fundamental Modes

    NASA Astrophysics Data System (ADS)

    Chang, Chih-Hsuan; Nesbitt, David

    2014-06-01

    Sub-Doppler jet-cooled rovibrational spectra of ND3H+, ND2H2+, and NDH3+ ions in various fundamental NH modes were observed and analyzed using difference frequency generation infrared spectroscopy. The ions were generated in the concentration-modulation slit-jet expansion via a H3+ proton transfer mechanism in a discharge mixture of ND3/H2O and H2 gases. NH mode excitation in ND3H+ ion yielded a prominent Q branch feature and parallel band rotational structure. Rotational transitions were confirmed unambiguously by four-line ground state combination differences within frequency measurement accuracy (10 MHz). The band origin was determined to be 3316.8413(9) cm-1. Perturbation in the upper state was observed from analysis of residuals. In the case of ND2H2+, both NH symmetric (b-type) and anti-symmetric (c-type) modes were observed and assigned for the first time, yielding band origins of 3297.5440(1) and 3337.9050(1) cm-1, respectively. The intensity for the two fundamental bands was interpreted with simple context of a bond-dipole model. The present study provided high precision ground state rotational constants (A"=4.85675(4), B"=3.96829(4), C"=3.44667(6) cm-1), which should facilitate microwave searches for isotope-substituted ammonium ions in the regions of interstellar medium, such as dense molecular clouds or younger stellar objects.

  10. The {sup 3}He(e,e'p){sup 2}H and {sup 4}He(e,e'p){sup 3}H reactions at high momentum transfer

    SciTech Connect

    Ford, William P.; Schiavilla, Rocco; Van Orden, J. W.

    2014-03-01

    We present updated calculations for observables in the processes {sup 3}He(e,e'p){sup 2}H, {sup 4}He(e,e'p){sup 3}H and {sup 4}He(e-vector, e'p-vector){sup 3}H. This update entails the implementation of improved nucleon-nucleon (NN) amplitudes to describe final state interactions (FSI) within a Glauber approximation and includes full spin-isospin dependence in the profile operator. In addition, an optical potential, which has also been updated since previous work, is utilized to treat FSI for the {sup 4}He(e,e'p){sup 3}H and {sup 4}He(e-vector, e'p-vector){sup 3}H reactions. The calculations are compared with experimental data and show good agreement between theory and experiment. Comparisons are made between the various approximations in the Glauber treatment, including model dependence due to the NN scattering amplitudes, rescattering contributions, and spin dependence. We also analyze the validity of the Glauber approximation at the kinematics the data is available, by comparing to the results obtained with the optical potential.

  11. Hydration of DNA by tritiated water and isotope distribution: a study by /sup 1/H, /sup 2/H, and /sup 3/H NMR spectroscopy

    SciTech Connect

    Mathur-De Vre, R.; Grimee-Declerck, R.; Lejeune, P.; Bertinchamps, A.J.

    1982-06-01

    The hydration layer of DNA (0.75%) in tritiated water represents 3.5% of solvent /sup 3/HHO. The combined effects of temperature (-6 to -40/sup 0/C) and H/sub 2/O//sup 2/H/sub 2/O solvent composition on the spin-lattice relaxation times of water protons and deuterons suggest selective distribution of isotopes in the hydration layer. The ''hydration isotope'' effect and the localization of tritiated water molecules in the hydration layer of DNA have important implications in describing the radiobiological effects of tritiated water because the initial molecular damage caused by /sup 3/HHO (internal radiation source) localizes close to /sup 3/H due to the short range and low energy of /sup 3/H ..beta.. rays.

  12. Synthesis, experimental, theoretical characterization and biological activities of 4-ethyl-5-(2-hydroxyphenyl)-2H-1,2,4-triazole-3(4H)-thione

    NASA Astrophysics Data System (ADS)

    Koparir, Metin; Orek, Cahit; Koparir, Pelin; Sarac, Kamiran

    2013-03-01

    This work presents the characterization of 4-ethyl-5-(2-hydroxyphenyl)-2H-1,2,4-triazole-3(4H)-thione (III) by quantum chemical calculations and spectral techniques. The molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO) 1H and 13C NMR chemical shift values of III in the ground state have been calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequencies and chemical shift values show good agreement with experimental values. To determine conformational flexibility, the molecular energy profile of the title compound was obtained by DFT calculations with respect to the selected torsion angle, which was varied from -180° to +180° in steps of 10°. The energetic behavior of III in solvent media was examined using the B3LYP method with the 6-31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). The predicted nonlinear optical properties of III are greater than ones of urea. In addition, DFT calculations of molecular electrostatic potentials and frontier molecular orbitals of III were carried out at the B3LYP/6-31G(d) level of theory. The title compound was screened for antibacterial, antifungal and antioxidant activities.

  13. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (VMSD1212, LB5136_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (VMSD1212, LB5136_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  14. Heat of Mixing and Solution of Ethanol C2H6O + C3H6O3 Dimethyl carbonate (HMSD1121, LB4328_H)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of Ethanol C2H6O + C3H6O3 Dimethyl carbonate (HMSD1121, LB4328_H)' providing data from direct calorimetric measurement of molar excess enthalpy at variable mole fraction and constant pressure and temperature.

  15. Heat of Mixing and Solution of Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (HMSD1111, LB4314_H)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (HMSD1111, LB4314_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  16. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (VMSD1111, LB5133_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (VMSD1111, LB5133_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  17. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H3N Propenenitrile (VMSD1111, LB4256_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H3N Propenenitrile (VMSD1111, LB4256_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  18. Vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C3H3N Propenenitrile (EVLM1211, LB5647_E)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C3H3N Propenenitrile (EVLM1211, LB5647_E)' providing data from direct measurement of temperature at variable mole fraction in liquid phase and constant pressure.

  19. Volumetric Properties of the Mixture Ethanenitrile C2H3N + C3H3N Propenenitrile (VMSD1111, LB4250_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethanenitrile C2H3N + C3H3N Propenenitrile (VMSD1111, LB4250_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  20. Volumetric Properties of the Mixture Ethanenitrile C2H3N + C3H3N Propenenitrile (VMSD1412, LB4277_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethanenitrile C2H3N + C3H3N Propenenitrile (VMSD1412, LB4277_V)' providing data by calculation of isentropic compressibility from low-pressure density and thermodynamic speed of sound data at variable mole fraction and constant temperature, in the single-phase region(s).

  1. Volumetric Properties of the Mixture Ethanol C2H6O + C3H3N Propenenitrile (VMSD1511, LB4925_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethanol C2H6O + C3H3N Propenenitrile (VMSD1511, LB4925_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  2. Volumetric Properties of the Mixture Ethanol C2H6O + C3H3N Propenenitrile (VMSD1212, LB4917_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethanol C2H6O + C3H3N Propenenitrile (VMSD1212, LB4917_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  3. Volumetric Properties of the Mixture Ethanenitrile C2H3N + C3H3N Propenenitrile (VMSD1511, LB4264_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethanenitrile C2H3N + C3H3N Propenenitrile (VMSD1511, LB4264_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  4. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H3N Propenenitrile (VMSD1212, LB4258_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H3N Propenenitrile (VMSD1212, LB4258_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  5. Volumetric Properties of the Mixture Ethanenitrile C2H3N + C3H3N Propenenitrile (VMSD1212, LB4257_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethanenitrile C2H3N + C3H3N Propenenitrile (VMSD1212, LB4257_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  6. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H3N Propenenitrile (VMSD1412, LB4276_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H3N Propenenitrile (VMSD1412, LB4276_V)' providing data by calculation of isentropic compressibility from low-pressure density and thermodynamic speed of sound data at variable mole fraction and constant temperature, in the single-phase region(s).

  7. Volumetric Properties of the Mixture Ethanol C2H6O + C3H3N Propenenitrile (VMSD1111, LB4908_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Ethanol C2H6O + C3H3N Propenenitrile (VMSD1111, LB4908_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  8. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H3N Propenenitrile (VMSD1511, LB4270_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H3N Propenenitrile (VMSD1511, LB4270_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  9. Study of the reactions /sup 2/H(d, p)/sup 3/H and /sup 2/H(d,n)/sup 3/He with a polarized deuteron beam. Extrapolation of the cross sections to the low-energy region

    SciTech Connect

    Ad'yasevich, B.P.; Antonenko, V.G.; Bragin, V.N.

    1981-05-01

    On the basis of analysis of experimental data on the vector analyzing power of the nuclear reactions /sup 2/H(d,p)/sup 3/H and /sup 2/H(d,n)/sup 3/He and data on the total cross sections for these reactions at energies from 13 to 485 keV we have separated the total cross sections into partial cross sections for s and p waves and have calculated the total cross sections for very low energies down to 0.3 keV. For these same reactions we have calculated the intensities of production of energetic products in a heated deuterium plasma. A formula for practical calculations of this intensity is obtained.

  10. Study of the reactions /sup 2/H(d,p)/sup 3/H and /sup 2/H(d,n)/sup 3/He with a polarized deuteron beam. Measurement of the analyzing power

    SciTech Connect

    Ad'yasevich, B.P.; Antonenko, V.G.; Fomenko, D.E.

    1981-03-01

    The angular distributions of all charged particles produced in the mirror reactions /sup 2/H(d,p)/sup 3/H and /sup 2/H(d,n)/sup 3/He in a gaseous deuterium target approx.10 keV thick have been measured for polarized-deuteron energies from 60 to 485 keV for various orientations of the beam axis. The angular distributions of the analyzing powers A/sub y/(theta), A/sub z/z(theta), A/sub x/z(theta), and A/sub x/x-yy(theta) have been measured for 12 values of the energy for each reaction at angles from 20/sup 0/ to 150/sup 0/ (in the laboratory frame). The results are shown as contour diagrams and compared with the results of similar experiments. The differences found are attributed to the effect of the target thickness and the energy calibration.

  11. Hydrazinium lanthanide oxalates: synthesis, structure and thermal reactivity of N2H5[Ln2(C2O4)4(N2H5)]·4H2O, Ln = Ce, Nd.

    PubMed

    De Almeida, Lucie; Grandjean, Stéphane; Rivenet, Murielle; Patisson, Fabrice; Abraham, Francis

    2014-03-28

    New hydrazinium lanthanide oxalates N2H5[Ln2(C2O4)4(N2H5)]·4H2O, Ln = Ce (Ce-HyOx) and Nd (Nd-HyOx), were synthesized by hydrothermal reaction at 150 °C between lanthanide nitrate, oxalic acid and hydrazine solutions. The structure of the Nd compound was determined from single-crystal X-ray diffraction data, space group P2₁/c with a = 16.315(4), b = 12.127(3), c = 11.430(2) Å, β = 116.638(4)°, V = 2021.4(7) Å(3), Z = 4, and R1 = 0.0313 for 4231 independent reflections. Two distinct neodymium polyhedra are formed, NdO9 and NdO8N, an oxygen of one monodentate oxalate in the former being replaced by a nitrogen atom of a coordinated hydrazinium ion in the latter. The infrared absorption band at 1005 cm(-1) confirms the coordination of N2H5(+) to the metal. These polyhedra are connected through μ2 and μ3 oxalate ions to form an anionic three-dimensional neodymium-oxalate arrangement. A non-coordinated charge-compensating hydrazinium ion occupies, with water molecules, the resulting tunnels. The N-N stretching frequencies of the infrared spectra demonstrate the existence of the two types of hydrazine ions. Thermal reactivity of these hydrazinium oxalates and of the mixed isotypic Ce/Nd (CeNd-HyOx) oxalate were studied by using thermogravimetric and differential thermal analyses coupled with gas analyzers, and high temperature X-ray diffraction. Under air, fine particles of CeO2 and Ce(0.5)Nd(0.5)O(1.75) are formed at low temperature from Ce-HyOx and CeNd-HyOx, respectively, thanks to a decomposition/oxidation process. Under argon flow, dioxymonocyanamides Ln2O2CN2 are formed. PMID:24468910

  12. Phenyl Substituted 4-Hydroxypyridazin-3(2H)-ones and 5-Hydroxypyrimidin-4(3H)-ones: Inhibitors of Influenza A Endonuclease

    PubMed Central

    2015-01-01

    Seasonal and pandemic influenza outbreaks remain a major human health problem. Inhibition of the endonuclease activity of influenza RNA-dependent RNA polymerase is attractive for the development of new agents for the treatment of influenza infection. Our earlier studies identified a series of 5- and 6-phenyl substituted 3-hydroxypyridin-2(1H)-ones that were effective inhibitors of influenza endonuclease. These agents identified as bimetal chelating ligands binding to the active site of the enzyme. In the present study, several aza analogues of these phenyl substituted 3-hydroxypyridin-2(1H)-one compounds were synthesized and evaluated for their ability to inhibit the endonuclease activity. In contrast to the 4-aza analogue of 6-(4-fluorophenyl)-3-hydroxypyridin-2(1H)-one, the 5-aza analogue (5-hydroxy-2-(4-fluorophenyl)pyrimidin-4(3H)-one) did exhibit significant activity as an endonuclease inhibitor. The 6-aza analogue of 5-(4-fluorophenyl)-3-hydroxypyridin-2(1H)-one (6-(4-fluorophenyl)-4-hydroxypyridazin-3(2H)-one) also retained modest activity as an inhibitor. Several varied 6-phenyl-4-hydroxypyridazin-3(2H)-ones and 2-phenyl-5-hydroxypyrimidin-4(3H)-ones were synthesized and evaluated as endonuclease inhibitors. The SAR observed for these aza analogues are consistent with those previously observed with various phenyl substituted 3-hydroxypyridin-2(1H)-ones. PMID:25225968

  13. The mode of vasorelaxant action of 2-aminoisoquinoline, 1.3 (2H.4H)-dione, a novel 'intracellular calcium inhibitor'.

    PubMed Central

    Hester, R. K.; Satake, N.; Shibata, S.; Ueda, S.; Yamahara, J.

    1986-01-01

    In rabbit aorta, pretreatment with 2-aminoisoquinoline, 1.3 (2H.4H)-dione (AQ, 10(-5) M and 10(-4) M) shifted the concentration-response relationship to noradrenaline (NA, 10(-9) M to 10(-4) M) in a parallel manner whereas the agent (10(-4) M) failed to affect the response to potassium and only slightly depressed Ca2+-induced contractions in a Ca2+-free medium in the presence of K+ (40 mM). Ca2+-entry blockers such as nifedipine and diltiazem (10(-6) M and 10(-5) M) had very weak or no apparent effects on the response to NA but markedly attenuated or abolished the K+- and Ca2+-induced contractions. Following incubation of tissues for 15 min in a Ca2+-free medium with low EGTA (0.01 mM) and methoxyverapamil (D600, 10(-5) M), NA (3 X 10(-7) M) caused a phasic (transient) contraction and the subsequent application of Ca2+ (2mM) resulted in a tonic contraction. This NA-induced, Ca2+-dependent, D600-insensitive contraction was inhibited by AQ (10(-5) M and 10(-4) M) in a concentration-dependent manner. This suggests that the inhibitory action of AQ may be related to Ca2+ entry through specific receptor activated pathways. Following incubation of tissues for 30 min in a Ca2+-free medium with high EGTA (2.0 mM), NA (10(-5) M) caused a contraction of rabbit aorta which is dependent upon release of intracellular Ca2+, but the response was 50% to 60% less than that in a normal medium. This contraction was inhibited by AQ (10(-5) M and 10(-4) M) and nitroglycerin (10(-5) M) but not by nifedipine or diltiazem.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3082401

  14. DETECTIONS OF C{sub 2}H, CYCLIC-C{sub 3}H{sub 2}, AND H{sup 13}CN IN NGC 1068

    SciTech Connect

    Nakajima, T.; Takano, S.; Kohno, K.; Inoue, H.

    2011-02-20

    We used the Nobeyama 45 m telescope to conduct a spectral line survey in the 3 mm band (85.1-98.4 GHz) toward one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068, and the prototypical starburst galaxy NGC 253. The beam size of this telescope is {approx} 18'', which was sufficient to spatially separate the nuclear molecular emission from the emission of the circumnuclear starburst region in NGC 1068. We detected rotational transitions of C{sub 2}H, cyclic-C{sub 3}H{sub 2}, and H{sup 13}CN in NGC 1068. These are detections of carbon-chain and carbon-ring molecules in NGC 1068. In addition, the C{sub 2}H N = 1-0 lines were detected in NGC 253. The column densities of C{sub 2}H were determined to be 3.4 x 10{sup 15} cm{sup -2} in NGC 1068 and 1.8 x 10{sup 15} cm{sup -2} in NGC 253. The column densities of cyclic-C{sub 3}H{sub 2} were determined to be 1.7 x 10{sup 13} cm{sup -2} in NGC 1068 and 4.4 x 10{sup 13} cm{sup -2} in NGC 253. We calculated the abundances of these molecules relative to CS for both NGC 1068 and NGC 253, and found that there were no significant differences in the abundances between the two galaxies. This result suggests that the basic carbon-containing molecules are either insusceptible to AGN or are tracing cold (T{sub rot} {approx} 10 K) molecular gas rather than X-ray irradiated hot gas.

  15. Theoretical study of the radiative capture reactions {sup 2}H(n,{gamma}){sup 3}H and {sup 2}H(p,{gamma}){sup 3}He at low energies

    SciTech Connect

    M. Viviani; R. Schiavilla; A. Kievsky

    1996-02-01

    Correlated Hyperspherical Harmonics wave functions with {Delta}-isobar admixtures obtained from realistic interactions are used to study the thermal neutron radiative capture on deuterium, and the {sup 2}H({rvec p},{gamma}){sup 3}He and p({rvec d},{gamma}){sup 3}He reactions in the center of mass energy range 0-100 keV. The nuclear electromagnetic current includes one and two-body components. Results for the {sup 2}H({rvec d},{gamma}){sup 3}H cross section and photon polarization parameter, as well as for the energy dependence of the astrophysical factor and angular distributions of the differential cross section, vector and tensor analyzing powers, and photon linear polarization coefficient of the {sup 2}H({rvec p},{gamma}){sup 3}He and p({rvec d},{gamma}){sup 3}He reactions are reported. Large effects due to two-body currents, in particular the long-range ones associated with the tensor component of the nucleon-nucleon interaction, are observed in the photon polarization parameter and vector analyzing power. Good, quantitative agreement between theory and experiment is found for all observables, with the exception of the vector analyzing power for which the calculated values underestimate the data by about 30%.

  16. Origin of methane in serpentinite-hosted hydrothermal systems: The CH4-H2-H2O hydrogen isotope systematics of the Hakuba Happo hot spring

    NASA Astrophysics Data System (ADS)

    Suda, Konomi; Ueno, Yuichiro; Yoshizaki, Motoko; Nakamura, Hitomi; Kurokawa, Ken; Nishiyama, Eri; Yoshino, Koji; Hongoh, Yuichi; Kawachi, Kenichi; Omori, Soichi; Yamada, Keita; Yoshida, Naohiro; Maruyama, Shigenori

    2014-01-01

    Serpentinite-hosted hydrothermal systems have attracted considerable attention as sites of abiotic organic synthesis and as habitats for the earliest microbial communities. Here, we report a systematic isotopic study of a new serpentinite-hosted system: the Hakuba Happo hot spring in the Shiroumadake area, Japan (36°42‧N, 137°48‧E). We collected water directly from the hot spring from two drilling wells more than 500 m deep; all water samples were strongly alkaline (pH>10) and rich in H2 (201-664 μmol/L) and CH4 (124-201 μmol/L). Despite the relatively low temperatures (50-60 °C), thermodynamic calculations suggest that the H2 was likely derived from serpentinization reactions. Hydrogen isotope compositions for Happo #1 (Happo #3) were found to be as follows: δD-H2=-700‰ (-710‰), δD-CH4=-210‰ (-300‰), and δD-H2O=-85‰ (-84‰). The carbon isotope compositions of methane from Happo #1 and #3 were found to be δC13=-34.5‰ and -33.9‰, respectively. The CH4-H2-H2O hydrogen isotope systematics indicate that at least two different mechanisms were responsible for methane formation. Happo #1 has a similar hydrogen isotope compositions to other serpentinite-hosted systems reported previously. The elevated δD-CH4 (with respect to the equilibrium relationship) suggests that the hydrogen of the Happo #1 methane was not sourced from molecular hydrogen but was derived directly from water. This implies that the methane may not have been produced via the Fischer-Tropsch-type (FTT) synthesis but possibly by the hydration of olivine. Conversely, the depleted δD-CH4 (with respect to the equilibrium relationship) in Happo #3 suggests the incorporation of biological methane. Based on a comparison of the hydrogen isotope systematics of our results with those of other serpentinite-hosted hydrothermal systems, we suggest that abiotic CH4 production directly from H2O (without mediation by H2) may be more common in serpentinite-hosted systems. Hydration of olivine

  17. Microwave Plasma-Activated Chemical Vapor Deposition of Nitrogen-Doped Diamond. I. N2/H2 and NH3/H2 Plasmas.

    PubMed

    Truscott, Benjamin S; Kelly, Mark W; Potter, Katie J; Johnson, Mack; Ashfold, Michael N R; Mankelevich, Yuri A

    2015-12-31

    We report a combined experimental/modeling study of microwave activated dilute N2/H2 and NH3/H2 plasmas as a precursor to diagnosis of the CH4/N2/H2 plasmas used for the chemical vapor deposition (CVD) of N-doped diamond. Absolute column densities of H(n = 2) atoms and NH(X(3)Σ(-), v = 0) radicals have been determined by cavity ring down spectroscopy, as a function of height (z) above a molybdenum substrate and of the plasma process conditions, i.e., total gas pressure p, input power P, and the nitrogen/hydrogen atom ratio in the source gas. Optical emission spectroscopy has been used to investigate variations in the relative number densities of H(n = 3) atoms, NH(A(3)Π) radicals, and N2(C(3)Πu) molecules as functions of the same process conditions. These experimental data are complemented by 2-D (r, z) coupled kinetic and transport modeling for the same process conditions, which consider variations in both the overall chemistry and plasma parameters, including the electron (Te) and gas (T) temperatures, the electron density (ne), and the plasma power density (Q). Comparisons between experiment and theory allow refinement of prior understanding of N/H plasma-chemical reactivity, and its variation with process conditions and with location within the CVD reactor, and serve to highlight the essential role of metastable N2(A(3)Σ(+)u) molecules (formed by electron impact excitation) and their hitherto underappreciated reactivity with H atoms, in converting N2 process gas into reactive NHx (x = 0-3) radical species. PMID:26593853

  18. Solvation effects on reactive intermediates: The benzyl radical and its clusters with Ar, N2, CH4, C2H6, and C3H8

    NASA Astrophysics Data System (ADS)

    Disselkamp, R.; Bernstein, E. R.

    1993-03-01

    Mass resolved excitation spectra are presented for the benzyl radical and its clusters with Ar, N2, CH4, C2H6, and C3H8. The cluster spectra exhibit small redshifts (≤50 cm-1) relative to the unclustered benzyl radical for the D1(1 2A2)←D0(1 2B2) and D2(2 2B2)←D0(1 2B2) electronic transition regions. A unique set of low energy van der Waals modes is observed for these clusters for each excited electronic state investigated. The cluster spectra also reveal significant vibronic coupling between the two excited electronic states of the benzyl radical, as evidenced by a single vibrational predissociation threshold for each cluster. Ab initio calculations are performed on the benzyl radical to examine excited electronic state structure, predict transition energies, estimate ionization energy, and determine partial atomic charges in the electronic states of interest. The resulting partial charges are used in empirical atom-atom potential energy calculations to aid in the understanding of cluster spectroscopic shifts, binding energies, and van der Waals modes.

  19. Thermoelectric properties of the 3C, 2H, 4H, and 6H polytypes of the wide-band-gap semiconductors SiC, GaN, and ZnO

    SciTech Connect

    Huang, Zheng; Lü, Tie-Yu; Wang, Hui-Qiong; Zheng, Jin-Cheng

    2015-09-15

    We have investigated the thermoelectric properties of the 3C, 2H, 4H, and 6H polytypes of the wide-band-gap(n-type) semiconductors SiC, GaN, and ZnO based on first-principles calculations and Boltzmann transport theory. Our results show that the thermoelectric performance increases from 3C to 6H, 4H, and 2H structures with an increase of hexagonality for SiC. However, for GaN and ZnO, their power factors show a very weak dependence on the polytype. Detailed analysis of the thermoelectric properties with respect to temperature and carrier concentration of 4H-SiC, 2H-GaN, and 2H-ZnO shows that the figure of merit of these three compounds increases with temperature, indicating the promising potential applications of these thermoelectric materials at high temperature. The significant difference of the polytype-dependent thermoelectric properties among SiC, GaN, and ZnO might be related to the competition between covalency and ionicity in these semiconductors. Our calculations may provide a new way to enhance the thermoelectric properties of wide-band-gap semiconductors through atomic structure design, especially hexagonality design for SiC.

  20. Down-regulation of p-coumaroyl quinate/shikimate 3'-hydroxylase (C3'H) and cinnamate 4-hydroxylase (C4H) genes in the lignin biosynthetic pathway of Eucalyptus urophylla x E. grandis leads to improved sugar release

    DOE PAGESBeta

    Sykes, Robert W.; Gjersing, Erica L.; Foutz, Kirk; Rottmann, William H.; Kuhn, Sean A.; Foster, Cliff E.; Ziebell, Angela; Turner, Geoffrey B.; Decker, Stephen R.; Hinchee, Maud A. W.; et al

    2015-08-27

    In this study, lignocellulosic materials provide an attractive replacement for food-based crops used to produce ethanol. Understanding the interactions within the cell wall is vital to overcome the highly recalcitrant nature of biomass. One factor imparting plant cell wall recalcitrance is lignin, which can be manipulated by making changes in the lignin biosynthetic pathway. In this study, eucalyptus down-regulated in expression of cinnamate 4-hydroxylase (C4H, EC 1.14.13.11) or p-coumaroyl quinate/shikimate 3'-hydroxylase (C3'H, EC 1.14.13.36) were evaluated for cell wall composition and reduced recalcitrance.

  1. Results from Boiling Temperature Measurements for Saturated Solutions in the Systems NaCl + Ca(NO3)2 + H2O, NaNO3 + KNO3 + H2O, and NaCl + KNO3 + H2O, and Dry Out Temperatures for NaCl + NaNO3 + KNO3 + Ca(NO3)2 + H2O

    SciTech Connect

    Rard, J A

    2005-11-29

    Boiling temperature measurements have been made for saturated ternary solutions of NaCl + KNO{sub 3} + H{sub 2}O and NaNO{sub 3} + KNO{sub 3} + H{sub 2}O at three selected salt ratios and for NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O over the full composition range. The maximum boiling temperature found for the NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O system is 164.7 {+-} 0.6 C, and the composition is estimated to occur at x(Ca(NO{sub 3}){sub 2}) {approx} 0.25. Experiments were also performed for the five component NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O mixtures with the molar ratio of NaCl:NaNO{sub 3}:KNO{sub 3} held essentially constant at 1:0.9780:1.1468 as the solute mole fraction of Ca(NO{sub 3}){sub 2}, x(Ca(NO{sub 3}){sub 2}), was varied between 0 and 0.25. The NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O system forms low melting mixtures and thus boiling temperatures for saturated were not determined. Instead, the temperatures corresponding to the cessation of boiling (i.e., dry out temperatures) of these liquid mixtures were determined. These dry out temperatures range from {approx} 300 C when x(Ca(NO{sub 3}){sub 2}) = 0 to {ge} 400 C when x(Ca(NO{sub 3}){sub 2}) = 0.20 and 0.25. The investigated mixture compositions correspond to some of the major mineral assemblages that are predicted to control the deliquescence relative humidity of salts formed by leaching dust samples from the proposed nuclear repository at Yucca Mountain, Nevada.

  2. Method for determination of .sup.18 O/.sup.16 O and .sup.2 H/.sup.1 H ratios and .sup.3 H (tritium) concentrations of xylem waters and subsurface waters using time series sampling

    SciTech Connect

    Smith, Brian; Menchaca, Leticia

    1999-01-01

    A method for determination of .sup.18 O/.sup.16 O and .sup.2 H/.sup.1 H ratios and .sup.3 H concentrations of xylem and subsurface waters using time series sampling, insulating sampling chambers, and combined .sup.18 O/.sup.16 O, .sup.2 H/.sup.1 H and .sup.3 H concentration data on transpired water. The method involves collecting water samples transpired from living plants and correcting the measured isotopic compositions of oxygen (.sup.18 O/.sup.16 O) and hydrogen (.sup.2 H/.sup.1 H and/or .sup.3 H concentrations) to account for evaporative isotopic fractionation in the leafy material of the plant.

  3. Method for determination of {sup 18}O/{sup 16}O and {sup 2}H/{sup 1}H ratios and {sup 3}H (tritium) concentrations of xylem waters and subsurface waters using time-series sampling

    SciTech Connect

    1999-11-09

    This application describes a method for the determination of {sup 18}O/{sup 16}O and {sup 2}H/{sup 1}H ratios and {sup 3}H concentrations of xylem and subsurface waters using time-series sampling, insulating sampling chambers, and combined {sup 18}O/{sup 16}O, {sup 2}H/{sup 1}H and {sup 3}H concentration data on transpired water. The method involves collecting water samples transpired from living plants and correcting the measured isotopic compositions of oxygen ({sup 18}O/{sup 16}O) and hydrogen ({sup 2}H/{sup 1}H and/or {sup 3}H concentrations) to account for evaporative isotopic fractionation in the leafy material of the plant.

  4. Palladium-catalyzed bisarylation of 3-alkylbenzofurans to 3-arylalkyl-2-arylbenzofurans on water: tandem C(sp(3))-H and C(sp(2))-H activation reactions of 3-alkylbenzofurans.

    PubMed

    Cho, Beom Shin; Chung, Young Keun

    2015-10-01

    A protocol involving facile sequential C(sp(3))-H and C(sp(2))-H activation reactions of 3-alkylbenzofurans catalyzed by Pd(OAc)2 in the presence of pivalic acid, silver salt, and tricyclohexylphosphine 'on water' was developed. Aryl iodides were used as substrates in a tandem bisarylation reaction to generate 3-arylalkyl-2-arylbenzofurans in moderate to high yields at room temperature. The reaction revealed in this study is a rare example of consecutive C(sp(3))-H and C(sp(2))-H bond activation under mild reaction conditions. PMID:26287028

  5. Synthesis, resolution and anticonvulsant activity of chiral N-1'-ethyl,N-3'-(1-phenylethyl)-(R,S)-2'H,3H,5'H-spiro-(2-benzofuran-1,4'-imidazolidine)-2',3,5'-trione diastereomers.

    PubMed

    Sadarangani, Ishwar R; Bhatia, Souful; Amarante, Daniel; Lengyel, Istvan; Stephani, Ralph A

    2012-04-01

    Four new N-1',N-3'-disubstituted-2'H,3H,5'H-spiro-(2-benzofuran-1,4'-imidazolidine)-2',3,5'-triones bearing a chiral N-3' substituent were synthesized, resolved and their anticonvulsant activity was obtained and determined that the activity was not stereoselective. PMID:22401865

  6. 21 CFR 73.3123 - 6-Ethoxy-2-(6-ethoxy-3-oxobenzo[b]thien-2(3H)-ylidene) benzo[b]thiophen-3 (2H)-one.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3123 6-Ethoxy-2-(6-ethoxy-3-oxobenzo thien-2(3H)-ylidene) benzo thiophen-3 (2H)-one....

  7. 21 CFR 73.3123 - 6-Ethoxy-2-(6-ethoxy-3-oxobenzo[b]thien-2(3H)-ylidene) benzo[b]thiophen-3 (2H)-one.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3123 6-Ethoxy-2-(6-ethoxy-3-oxobenzo thien-2(3H)-ylidene) benzo thiophen-3 (2H)-one....

  8. Measurements of the Differential Cross Sections for the Elastic n-{sup 3}H and n-{sup 2}H Scattering at 14.1 MeV by Using an Inertial Confinement Fusion Facility

    SciTech Connect

    Frenje, J. A.; Li, C. K.; Seguin, F. H.; Casey, D. T.; Petrasso, R. D.; McNabb, D. P.; Navratil, P.; Quaglioni, S.; Sangster, T. C.; Glebov, V. Yu; Meyerhofer, D. D.

    2011-09-16

    For the first time the differential cross section for the elastic neutron-triton (n-{sup 3}H) and neutron-deuteron (n-{sup 2}H) scattering at 14.1 MeV has been measured by using an inertial confinement fusion facility. In these experiments, which were carried out by simultaneously measuring elastically scattered {sup 3}H and {sup 2}H ions from a deuterium-tritium gas-filled inertial confinement fusion capsule implosion, the differential cross section for the elastic n-{sup 3}H scattering was obtained with significantly higher accuracy than achieved in previous accelerator experiments. The results compare well with calculations that combine the resonating-group method with an ab initio no-core shell model, which demonstrate that recent advances in ab initio theory can provide an accurate description of light-ion reactions.

  9. Vapor-Liquid Equilibrium in the Mixture 1,1,1,2-Tetrafluoroethane C2H2F4 + C4H10O2 2,5-Dioxahexane (EVLM1111, LB5748_E)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,1,1,2-Tetrafluoroethane C2H2F4 + C4H10O2 2,5-Dioxahexane (EVLM1111, LB5748_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  10. Experimentally determined standard thermodynamic properties of synthetic MgSO(4)·4H(2)O (Starkeyite) and MgSO(4)·3H(2)O: a revised internally consistent thermodynamic data set for magnesium sulfate hydrates.

    PubMed

    Grevel, Klaus-Dieter; Majzlan, Juraj; Benisek, Artur; Dachs, Edgar; Steiger, Michael; Fortes, A Dominic; Marler, Bernd

    2012-11-01

    The enthalpies of formation of synthetic MgSO(4)·4H(2)O (starkeyite) and MgSO(4)·3H(2)O were obtained by solution calorimetry at T=298.15 K. The resulting enthalpies of formation from the elements are [Formula: see text] (starkeyite)=-2498.7±1.1 kJ·mol(-1) and [Formula: see text] (MgSO(4)·3H(2)O)=-2210.3±1.3 kJ·mol(-1). The standard entropy of starkeyite was derived from low-temperature heat capacity measurements acquired with a physical property measurement system (PPMS) in the temperature range 5 K

  11. Localization of MOs and electronic populations in closo-carboranes 1, 5-C/sub 2/B/sub 3/H/sub 5/ and 1,6-C/sub 2/B/sub 4/H/sub 6/

    SciTech Connect

    Semenov, S.G.

    1988-01-01

    We have analyzed the electronic populations of chemical bonds and atoms in the highly symmetric closo-carboranes 1,5-C/sub 2/B/sub 3/H/sub 5/ (I) and 1,6-C/sub 2/B/sub 4/H/sub 6/ (II). The overlap populations sigma/sub XY/ are compared with the corresponding Mulliken indices. We note substantial nonadditivity of the populations sigma/sub XY/ for closed three-center bonds BCB' and the closeness of the total overlap populations sigma/sub t/ to its maximum value. We have established the localization of the natural MOs on the bonds CH, BH, and BCB', and for molecule I also on the CBC' bonds. The effects of conjugation of bonds in the closo-carborane polyhedron are apparent in the linear dependence of these MOs. The corresponding nonorthogonal hybrid AOs of carbon and boron are also linearly dependent. We have formulated the concept of unshared population of an atom.

  12. Vibrational spectroscopic study of the natural layered double hydroxide manasseite now defined as hydrotalcite-2H - Mg6Al2(OH)16[CO3]ṡ4H2O

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Scholz, Ricardo; López, Andrés; Theiss, Frederick L.

    2014-01-01

    Raman and thermo-Raman spectroscopy have been applied to study the mineral formerly known as manasseite now simply renamed as hydrotalcite-2H Mg6Al2(OH)16[CO3]ṡ4H2O. The mineral is a member of the homonymous hydrotalcite supergroup. Hydrogen bond distances calculated using a Libowitzky-type empirical function varied between 2.61 and 3.00 Å. Stronger hydrogen bonds were formed by water units as compared to the hydroxyl units. Raman spectroscopy enabled the identification of bands attributed to the hydroxyl units. Two Raman bands at 1059 and 1064 cm-1 are assigned to symmetric stretching modes of the carbonate anion. Thermal treatment shifts these bands to higher wavenumbers indicating a change in the strength of the carbonate bonding.

  13. In vitro evaluation of the antioxidant and antimicrobial activity of DIMBOA [2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one].

    PubMed

    Gleńsk, Michał; Gajda, Beata; Franiczek, Roman; Krzyżanowska, Barbara; Biskup, Izabela; Włodarczyk, Maciej

    2016-06-01

    The aim of this study was to evaluate the in vitro antioxidant and antimicrobial properties of the natural cyclic hydroxamic acid: 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA). Antioxidant activity of the isolated DIMBOA was examined using DPPH, FRAP and ABTS tests. It was found that DIMBOA exhibits a potent free-radical scavenging activity and a weaker iron (III) ions reducing activity. Antimicrobial activity against selected G(+), G(-) bacterial strains and against yeasts-like reference strains of fungi was investigated using disk-diffusion method. It has been shown that DIMBOA possess growth inhibitory properties against many strains of studied bacteria and fungi, such as Staphylococcus aureus, Escherichia coli as well as against Saccharomyces cerevisiae. PMID:26166773

  14. Effects of distortion of the intercluster motion in {sup 2}H, {sup 3}He, {sup 3}H, {sup 6}Li, and {sup 9}Be on Trojan horse applications

    SciTech Connect

    Pizzone, R. G.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Romano, S.; Mukhamedzhanov, A. M.; Blokhintsev, L. D.; Bertulani, C. A.; Irgaziev, B. F.

    2009-08-15

    Deuteron induced quasifree scattering and reactions have been extensively investigated in the past few decades as well as {sup 6}Li, {sup 3}H, {sup 3}He, and {sup 9}Be induced reactions. This was done not only for the investigation of nuclear structure and reaction mechanisms but also for important astrophysical applications (Trojan horse method). In particular the widths of the spectator momentum distributions in several nuclei, which have been used as Trojan horses, have been obtained as a function of the transferred momentum. Applications of Trojan horse method will also be discussed because the momentum distribution of the spectator particle inside the nucleus is a important input for this method. This gives hints on distortion effects at low energies important for nuclear astrophysics.

  15. MOLECULAR SURVIVAL IN EVOLVED PLANETARY NEBULAE: DETECTION OF H{sub 2}CO, c-C{sub 3}H{sub 2}, AND C{sub 2}H IN THE HELIX

    SciTech Connect

    Tenenbaum, E. D.; Woolf, N. J.; Ziurys, L. M.; Milam, S. N. E-mail: nwoolf@as.arizona.ed E-mail: Stefanie.N.Milam@nasa.go

    2009-10-20

    H{sub 2}CO, c-C{sub 3}H{sub 2}, and C{sub 2}H have been identified in the neutral envelope of the highly evolved planetary nebula (PN), the Helix (also know as NGC 7293). Emission from these species were detected toward a peak position in CO, 372'' east of the central star, using the facilities of the Arizona Radio Observatory (ARO). C{sub 2}H and c-C{sub 3}H{sub 2} were identified on the basis of their 3 mm transitions, measured with the ARO 12 m, while five lines of H{sub 2}CO were observed using the 12 m at 2 and 3 mm and the ARO Submillimeter Telescope at 1 mm. From a radiative transfer analysis of the formaldehyde emission, the molecular material was determined to have a density of n(H{sub 2}) approx3 x 10{sup 5} cm{sup -3}, with a kinetic temperature of T {sub kin} approx20 K. Column densities for C{sub 2}H, H{sub 2}CO, and c-C{sub 3}H{sub 2} of N {sub tot} approx1.4 x 10{sup 13} cm{sup -2}, 1.1 x 10{sup 12} cm{sup -2}, and 3 x 10{sup 11} cm{sup -2}, respectively, were derived, corresponding to fractional abundances relative to H{sub 2} of f (H{sub 2}CO) = 1 x 10{sup -7}, f (c-C{sub 3}H{sub 2}) = 3 x 10{sup -8}, and f (C{sub 2}H) = 1 x 10{sup -6} {sub .} The physical conditions found support the notion that molecules in evolved PNe survive in dense clumps in pressure equilibrium, shielded from photodissociation. The presence of H{sub 2}CO, c-C{sub 3}H{sub 2}, and C{sub 2}H, along with the previously observed species CN, HNC, HCN, and HCO{sup +}, indicates that a relatively complex chemistry can occur in the late stages of PN evolution, despite potentially destructive ultraviolet radiation. These molecules have also been observed in diffuse clouds, suggesting a possible connection between molecular material in evolved PNe and the diffuse ISM.

  16. New potent inhibitors of tyrosinase: novel clues to binding of 1,3,4-thiadiazole-2(3H)-thiones, 1,3,4-oxadiazole-2(3H)-thiones, 4-amino-1,2,4-triazole-5(4H)-thiones, and substituted hydrazides to the dicopper active site.

    PubMed

    Ghani, Usman; Ullah, Nisar

    2010-06-01

    A series of 1,3,4-thiadiazole-2(3H)-thiones, 1,3,4-oxadiazole-2(3H)-thiones, 4-amino-1,2,4-triazole-5(4H)-thiones, and substituted hydrazides were tailored and synthesized as new potent inhibitors of tyrosinase. The rationale for inhibitor design was based on the active site structural evidence from the crystal structures of bacterial tyrosinase and potato catechol oxidase enzymes. Kinetic and active site binding studies suggested mono-dentate binding of thiadiazole, oxadiazole, and triazole rings to the active site dicopper center of tyrosinase including hydrophobicity contributing to the potent inhibition. Kinetic plots showed mixed-type of inhibition by all 25 compounds. Substitutions at C3 of the triazole ring and C5 of the thiadiazole/oxadiazole rings were found to be playing a major role in the high binding affinity to tyrosinase. The current work may help develop new potent tyrosinase inhibitors against hyperpigmentation including potential insecticides. PMID:20452224

  17. Intercalation of lanthanides into H/sub 3/OUO/sub 2/PO/sub 4/ x 3H/sub 2/O and C/sub 4/H/sub 9/NH/sub 3/UO/sub 2/PO/sub 4/ x 3H/sub 2/O

    SciTech Connect

    Pozas-Tormo, R.; Moreno-Real, L.; Martinez-Lara, M.; Bruque-Gamez, S.

    1987-05-06

    The ion-exchange reactions of La/sup 3 +/, Pr/sup 3 +/, and Nd/sup 2 +/ with H/sub 3/OUO/sub 2/PO/sub 4/ x 3H/sub 2/O (HUP) and C/sub 4/H/sub 9/NH/sub 3/UO/sub 2/PO/sub 4/ x 3 H/sub 2/O (BAUP) involve a topotactic process that results in final products derived from HUP having a tetragonal structure. The infrared spectra show the gradual disappearance of the vibration band of the mobile H/sub 3/O/sup +/ (1740 cm/sup -1/) as the interacalation of the Ln/sub aq//sup 2 +/ ions proceeds. The obtained solids conform to the following compositions: La(UO/sub 2//sup 2/PO/sub 4/)/sub 3/ X 14H/sub 2/O, Pr(UO/sub 2/PO/sub 4/)/sub 3/ x 14H/sub 2/O, and Nd(UO/sub 2/PO/sub 4/)/sub 3/ x 13 H/sub 2/O. The diffuse-reflectance electron spectra for the lanthanum derivative show only the characteristic bands of the UO/sub 2//sup 2 +/ group, while in the cases of Pr/sup 3 +/ and Nd/sup 3 +/, in addition to these bands, there are others in the 500-800-nm zone that correspond to these aqueous ions.

  18. Gas-phase reactions of the bare Th2+ and U2+ ions with small alkanes, CH4, C2H6, and C3H8: experimental and theoretical study of elementary organoactinide chemistry.

    PubMed

    Di Santo, Emanuela; Santos, Marta; Michelini, Maria C; Marçalo, Joaquim; Russo, Nino; Gibson, John K

    2011-02-16

    The gas-phase reactions of two dipositive actinide ions, Th(2+) and U(2+), with CH(4), C(2)H(6), and C(3)H(8) were studied by both experiment and theory. Fourier transform ion cyclotron resonance mass spectrometry was employed to study the bimolecular ion-molecule reactions; the potential energy profiles (PEPs) for the reactions, both observed and nonobserved, were computed by density functional theory (DFT). The experiments revealed that Th(2+) reacts with all three alkanes, including CH(4) to produce ThCH(2)(2+), whereas U(2+) reacts with C(2)H(6) and C(3)H(8), with different product distributions than for Th(2+). The comparative reactivities of Th(2+) and U(2+) toward CH(4) are well explained by the computed PEPs. The PEPs for the reactions with C(2)H(6) effectively rationalize the observed reaction products, ThC(2)H(2)(2+) and UC(2)H(4)(2+). For C(3)H(8) several reaction products were experimentally observed; these and additional potential reaction pathways were computed. The DFT results for the reactions with C(3)H(8) are consistent with the observed reactions and the different products observed for Th(2+) and U(2+); however, several exothermic products which emerge from energetically favorable PEPs were not experimentally observed. The comparison between experiment and theory reveals that DFT can effectively exclude unfavorable reaction pathways, due to energetic barriers and/or endothermic products, and can predict energetic differences in similar reaction pathways for different ions. However, and not surprisingly, a simple evaluation of the PEP features is insufficient to reliably exclude energetically favorable pathways. The computed PEPs, which all proceed by insertion, were used to evaluate the relationship between the energetics of the bare Th(2+) and U(2+) ions and the energies for C-H and C-C activation. It was found that the computed energetics for insertion are entirely consistent with the empirical model which relates insertion efficiency to the

  19. Synthesis, SAR Study and Evaluation of Mannich and Schiff Bases of Pyrazol-5(4H)-one Moiety Containing 3-(Hydrazinyl)-2-phenylquinazolin-4(3H)-one

    PubMed Central

    Sivakumar, K. K.; Rajasekharan, A.; Rao, R.; Narasimhan, B.

    2013-01-01

    In the present investigation, a series of 12 Mannich bases (QP1-12) and 5 Schiff bases (QSP1-5) of pyrazol-5(4H)-one moiety containing 3-(hydrazinyl)-2-phenylquinazolin-4(3H)-one has been synthesized and characterized by physicochemical as well as spectral means. The synthesized Mannich and Schiff bases were screened for their preliminary antimicrobial activity against Gram-positive and Gram-negative bacterial as well as fungal strains by the determination of zone of inhibition. Mannich bases (QP1-12) were found to be more potent antibacterial agents against Gram-positive bacteria, whereas Schiff bases (QSP1-5) were more potent against Gram-negative bacteria and fungi. Minimum inhibitory concentration result demonstrated that Mannich base compound (QP7) having ortho -OH and para -COOH group showed some improvement in antibacterial activity (minimum inhibitory concentration of 48.88×10−3 μM/ml) among the tested Gram-positive organisms and it also exhibit minimum inhibitory concentration of value of 12.22×10−3 μM/ml for Klebsiella pneumoniae. The antitubercular activity of synthesized compounds against Mycobacterium tuberculosis (H37Rv) was determined using microplate alamar blue assay. Compound QP11 showed appreciable antitubercular activity (minimum inhibitory concentration of 6.49×10−3 μM/ml) which was more active than the standard drugs, ethambutol (minimum inhibitory concentration of 7.60×10−3 μM/ml) and ciprofloxacin (9.4×10−3 μM/ml). Compounds QP11, QP9, QSP1, QSP2, and QSP5 have good selective index and may be selected as a lead compound for the development of novel antitubercular agents. PMID:24302802

  20. Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO4·4H2O (Starkeyite) and MgSO4·3H2O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

    PubMed Central

    Majzlan, Juraj; Benisek, Artur; Dachs, Edgar; Steiger, Michael; Fortes, A. Dominic; Marler, Bernd

    2012-01-01

    Abstract The enthalpies of formation of synthetic MgSO4·4H2O (starkeyite) and MgSO4·3H2O were obtained by solution calorimetry at T=298.15 K. The resulting enthalpies of formation from the elements are \\documentclass{aastex}\\usepackage{amsbsy}\\usepackage{amsfonts}\\usepackage{amssymb}\\usepackage{bm}\\usepackage{mathrsfs}\\usepackage{pifont}\\usepackage{stmaryrd}\\usepackage{textcomp}\\usepackage{portland, xspace}\\usepackage{amsmath, amsxtra}\\pagestyle{empty}\\DeclareMathSizes{10}{9}{7}{6}\\begin{document}$$\\Delta_{ \\rm f}H^0_{298}$$\\end{document} (starkeyite)=−2498.7±1.1 kJ·mol−1 and \\documentclass{aastex}\\usepackage{amsbsy}\\usepackage{amsfonts}\\usepackage{amssymb}\\usepackage{bm}\\usepackage{mathrsfs}\\usepackage{pifont}\\usepackage{stmaryrd}\\usepackage{textcomp}\\usepackage{portland, xspace}\\usepackage{amsmath, amsxtra}\\pagestyle{empty}\\DeclareMathSizes{10}{9}{7}{6}\\begin{document}$$\\Delta_{ \\rm f}H^0_{298}$$\\end{document} (MgSO4·3H2O)=−2210.3±1.3 kJ·mol−1. The standard entropy of starkeyite was derived from low-temperature heat capacity measurements acquired with a physical property measurement system (PPMS) in the temperature range 5 K

  1. Vapor-Liquid Equilibrium in the Mixture 1,1,2,2-Tetrachloroethane C2H2Cl4 + C3H3N Propenenitrile (EVLM1211, LB5648_E)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,1,2,2-Tetrachloroethane C2H2Cl4 + C3H3N Propenenitrile (EVLM1211, LB5648_E)' providing data from direct measurement of temperature at variable mole fraction in liquid phase and constant pressure.

  2. Energy transport in photoexcited crystals of K3[Tb(C2O4)3(H2O)].2H2O: Transfer from Tb3+ to Nd3+ and Eu3+

    NASA Astrophysics Data System (ADS)

    Kahwa, Ishenkumba A.; Parkes, Charmaine C.; McPherson, Gary L.

    1995-10-01

    The luminescence decay dynamics of Tb3+(5D4) and Eu(5D0) in triclinic (P1¯) crystalline K3[Ln(C2O4)3(H2O)].2H2O solids was studied between 10 and 298 K in order to establish the energy-transport characteristics. The luminescence decay rate of Tb3+ (740 s-1 for Ln=Tb3+) is temperature independent for the pure terbium complex; with introduction of Ln3+ dopants (e.g., Ln=Nd, Eu) faster decay rates which are temperature dependent are obtained. For the Eu3+ dopant, excitation buildup on the Eu3+(5D0) decay curve upon Tb3+(5D4) excitation confirms that energy transfer from Tb3+(5D4) to Ln3+ is active. The temperature dependence of the energy-transfer process in the K3[Eu0.83Tb0.17(C2O4)3(H2O)].2H2O mixed complex is well described by a relatively simple empirical expression based on Boltzmann's statistical dynamics of Eu3+ electronic energy among the 7FJ (J=0,1,2) terms. The limiting Eu3+-Tb3+ transfer rates are ~5.4×103 and 5.3×104 s-1 at 77 and 298 K, respectively. Energy migration on the terbium sublattice was confirmed by comparing Huber's [Phys. Rev. B 20, 2707 (1979)] trapping functions for K3[Eu0.4Tb0.6(C2O4)3(H2O)].2H2O and K3[Eu0.4Tb0.1Gd0.5(C2O4)3(H2O)].2H2O (Gd3+ serving as a scatterer for Tb3+ excitation). Although the structure of the complexes features a one-dimensional zigzag array of Ln3+ ions, energy transport is diffusive and not one dimensional.

  3. Pd-Catalyzed sequential β-C(sp(3))-H arylation and intramolecular amination of δ-C(sp(2))-H bonds for synthesis of quinolinones via an N,O-bidentate directing group.

    PubMed

    Guan, Mingyu; Pang, Yubo; Zhang, Jingyu; Zhao, Yingsheng

    2016-05-19

    The pharmacological importance of 2-quinolinone derivatives is well known. Herein, we developed an effective protocol for the synthesis of 2-quinolinone derivatives by palladium-catalyzed sequential β-C(sp(3))-H arylation and selective intramolecular C(sp(2))-H/N-H amination starting with aryl iodides and carboxylic acids. A novel directing group, glycine dimethylamide, was used in the synthesis. We synthesized various quinolinone derivatives, including 5-substituted quinolinones, which are difficult to obtain using the traditional pathway. The directing group could be easily removed and could be readily transformed into other useful functional groups. PMID:27161570

  4. Coordination Modes of Americium in the Am2(C2O4)3(H2O)6·4H2O Oxalate: Synthesis, Crystal Structure, Spectroscopic Characterizations and Comparison in the M2(C2O4)3(H2O)6·nH2O (M = Ln, An) Series.

    PubMed

    Tamain, C; Arab-Chapelet, B; Rivenet, M; Legoff, X F; Loubert, G; Grandjean, S; Abraham, F

    2016-01-01

    Americium oxalate single crystals, Am2(C2O4)3(H2O)6·4H2O, were prepared by in situ oxalic acid generation by slow hydrolysis of the diester. Their structure was determined by single-crystal X-ray diffraction and was solved by the direct methods and Fourier difference techniques. The structure (space group P21/c, a = 11.184(4) Å, b = 9.489(4) Å, c = 10.234(4) Å, β = 114.308(8)°, Z = 2) consists of layers formed by six-membered rings of actinide metals connected through oxalate ions. The americium atoms are nine-coordinated by six oxygen atoms from three bidentate oxalate ligands and three water molecules. The distances within the coordination sphere as well as infrared and Raman spectra of several isostructural lanthanide (Ce(III), Pr(III), Nd(III), Sm(III), Gd(III)) and actinide (Pu(III), Am(III)) oxalates were compared to evaluate the similarities and the differences between the two series. PMID:26675037

  5. Monitoring dehydration of the organic-inorganic [(C3H7)4N][SnCl5(H2O)]·2H2O compound using simultaneous thermal and Raman studies

    NASA Astrophysics Data System (ADS)

    Hajlaoui, S.; Chaabane, I.; Guidara, K.; Bulou, A.

    2016-07-01

    In this work we report the experimental studies of the structural phase transition in the [(C3H7)4N]SnCl5(H2O)]·2H2O compound by differential scanning calorimetric (DSC) and Raman spectroscopic. The X-ray powder diffraction study of the [(C3H7)4N][SnCl5(H2O)]·2H2O sample at room temperature showed that this compound is monoclinic and has P121/c1 space group. Differential scanning calorimetric disclosed two types of phase transitions in the temperature range 356-376 (T1) K and at 393 K (T2) characterized, by a loss of water molecules and probably a reconstruction of new anionic parts after T2 transition. The Raman scattering spectra recorded at various temperatures in the wavenumber range from 100 to 3800 cm- 1 covering the domains of existence of changes in the vicinity of the two phase transitions detected by DSC measurement. A detailed study of the spectral parameters (wave number, reduced intensity and the full width at half maximum) as a function of temperature of a chosen band, associated with (νs(Snsbnd O) + νs(Snsbnd Cl)), based on an order-disorder model allowed us to obtain information relative to the activation energy and correlation length.

  6. Study of the tau- ---> pi- pi- pi+ pi0 pi0 nu/tau and tau- --> 3h- 2h+ nu/tau Decays Using the BaBar Detector

    SciTech Connect

    Sobie, R.; /Victoria U.

    2005-06-21

    The {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{pi}{sup 0}{pi}{sup 0}{nu}{sub {tau}} and {tau}{sup -} {yields} 3h{sup -} 2h{sup +} {nu}{sub {tau}} decays have been studied using the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring. Preliminary branching fractions are given for the {tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{pi}{sup 0}{pi}{sup 0}{nu}{sub {tau}} and to the sub-channels {tau}{sup -} {yields} {eta}{pi}{sup -} {pi}{sup 0}{nu}{sub {tau}} and {tau}{sup -} {yields} {omega}(782){pi}{sup -}{pi}{sup 0}{nu}{sub {tau}}. A preliminary upper limit is given on the branching fraction for the {phi}(1020){pi}{sup -}{pi}{sup 0}{nu}{sub {tau}} mode. In addition a preliminary measurement of the branching fraction of the {tau}{sup -} {yields} 3h{sup -}2h{sup +} {nu}{sub {tau}} decay (h = {pi}, K) is presented.

  7. Monitoring dehydration of the organic-inorganic [(C3H7)4N][SnCl5(H2O)]·2H2O compound using simultaneous thermal and Raman studies.

    PubMed

    Hajlaoui, S; Chaabane, I; Guidara, K; Bulou, A

    2016-07-01

    In this work we report the experimental studies of the structural phase transition in the [(C3H7)4N]SnCl5(H2O)]·2H2O compound by differential scanning calorimetric (DSC) and Raman spectroscopic. The X-ray powder diffraction study of the [(C3H7)4N][SnCl5(H2O)]·2H2O sample at room temperature showed that this compound is monoclinic and has P121/c1 space group. Differential scanning calorimetric disclosed two types of phase transitions in the temperature range 356-376 (T1) K and at 393K (T2) characterized, by a loss of water molecules and probably a reconstruction of new anionic parts after T2 transition. The Raman scattering spectra recorded at various temperatures in the wavenumber range from 100 to 3800cm(-1) covering the domains of existence of changes in the vicinity of the two phase transitions detected by DSC measurement. A detailed study of the spectral parameters (wave number, reduced intensity and the full width at half maximum) as a function of temperature of a chosen band, associated with (νs(SnO)+νs(SnCl)), based on an order-disorder model allowed us to obtain information relative to the activation energy and correlation length. PMID:27070530

  8. On the Formation and Isomer Specific Detection of Propenal (C2H3CHO) and Cyclopropanone (c-C3H4O) in Interstellar Model Ices - A Combined FTIR and Reflectron Time-of-Flight Mass Spectroscopic Study

    NASA Astrophysics Data System (ADS)

    Abplanalp, Matthew J.; Borsuk, Aleca; Jones, Brant M.; Kaiser, Ralf I.

    2015-11-01

    The formation routes of two structural isomers—propenal (C2H3CHO) and cyclopropanone (c-C3H4O)—were investigated experimentally by exposing ices of astrophysical interest to energetic electrons at 5.5 K thus mimicking the interaction of ionizing radiation with interstellar ices in cold molecular clouds. The radiation-induced processing of these ices was monitored online and in situ via Fourier Transform Infrared spectroscopy and via temperature programmed desorption exploiting highly sensitive reflectron time-of-flight mass spectrometry coupled with single photon ionization in the post irradiation phase. To selectively probe which isomer(s) is/are formed, the photoionization experiments were conducted with 10.49 and 9.60 eV photons. Our studies provided compelling evidence on the formation of both isomers—propenal (C2H3CHO) and cyclopropanone (c-C3H4O)—in ethylene (C2H4)—carbon monoxide (CO) ices forming propenal and cyclopropanone at a ratio of (4.5 ± 0.9):1. Based on the extracted reaction pathways, the cyclopropanone molecule can be classified as a tracer of a low temperature non-equilibrium chemistry within interstellar ices involving most likely excited triplet states, whereas propenal can be formed at ultralow temperatures, but also during the annealing phase via non-equilibrium as well as thermal chemistry (radical recombination). Since propenal has been detected in the interstellar medium and our laboratory experiments demonstrate that both isomers originated from identical precursor molecules our study predicts that the hitherto elusive second isomer—cyclopropanone—should also be observable toward those astronomical sources such as Sgr B2(N) in which propenal has been detected.

  9. Clathration of Two-Dimensional Coordination Polymers: Synthesis and Structures of [M(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(2).(2,4'-bpy)(2).H(2)O and [Cu(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(4).(4,4'-H(2)Bpy) (M = Cd(II), Zn(II) and bpy = Bipyridine).

    PubMed

    Tong, Ming-Liang; Ye, Bao-Hui; Cai, Ji-Wen; Chen, Xiao-Ming; Ng, Seik Weng

    1998-06-01

    In the presence of guest 2,4'-bpy molecules or under acidic conditions, three compounds, [Cd(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(2).(2,4'-bpy)(2).H(2)O (1), [Zn(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(2).(2,4'-bpy)(2).H(2)O (2), and [Cu(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(4).(4,4'-H(2)bpy) (3), were obtained from the reactions of the metal salts and 4,4'-bpy in an EtOH-H(2)O mixture. 1 has a 2-D square-grid network structure, crystallizing in the monoclinic space group P2/n, with a = 13.231(3) Å, b = 11.669(2) Å, c = 15.019(3) Å, beta = 112.82(3) degrees, Z = 2; 2 is isomorphous with 1, crystallizing in the monoclinic space group P2/n, with a = 13.150(3) Å, b = 11.368(2) Å, c = 14.745(3) Å, beta = 110.60(3) degrees, Z = 2. The square grids superpose on each other into a channel structure, in which each layer consists of two pairs of shared edges, perfectly square-planar with an M(II) ion and a 4,4'-bpy at each corner and side, respectively. The square cavity has dimensions of 11.669(2) x 11.788(2) and 11.368(2) x 11.488(2) Å for 1 and 2, respectively. Every two guest 2,4'-bpy molecules are clathrated in each hydrophobic host cavity and are further stabilized by pi-pi stacking and hydrogen bonding interactions. The NMR spectra clearly confirm that both 1 and 2 contain 4,4'-bpy and 2,4'-bpy molecules in a 1:1 ratio, which have stacking interaction with each other in the solution. 3 crystallizes in the orthorhombic space group Ibam, with a = 11.1283(5) Å, b = 15.5927(8) Å, c = 22.3178(11) Å, Z = 4. 3 is made up of two-dimensional square [Cu(4)(4,4'-bpy)(4)] grids, where the square cavity has dimensions of 11.13 x 11.16 Å. Each [4,4'-H(2)bpy](2+) cation is clathrated in a square cavity and stacks with one pair of opposite edges of the host square cavity in an offset fashion with the face-to-face distance of ca. 3.95 Å. Within each cavity, the [4,4'-H(2)bpy](2+) cation forms twin three-center hydrogen bonds with two pairs of ClO(4)(-) anions. The results suggest that the

  10. ACE-FTS observation of a young biomass burning plume: first reported measurements of C2H4, C3H6O, H2CO and PAN by infrared occultation from space

    NASA Astrophysics Data System (ADS)

    Coheur, P.-F.; Herbin, H.; Clerbaux, C.; Hurtmans, D.; Wespes, C.; Carleer, M.; Turquety, S.; Rinsland, C. P.; Remedios, J.; Hauglustaine, D.; Boone, C. D.; Bernath, P. F.

    2007-10-01

    In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACE-FTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they suggest that the emissions for this event likely originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE-FTS spectra over a wide wavenumber range (750-4400 cm-1), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) and CH3COO2NO2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.

  11. ACE-FTS observation of a young biomass burning plume: first reported measurements of C2H4, C3H6O, H2CO and PAN by infrared occultation from space

    NASA Astrophysics Data System (ADS)

    Coheur, P.-F.; Herbin, H.; Clerbaux, C.; Hurtmans, D.; Wespes, C.; Carleer, M.; Turquety, S.; Rinsland, C. P.; Remedios, J.; Hauglustaine, D.; Boone, C. D.; Bernath, P. F.

    2007-06-01

    In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACE-FTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they demonstrate that the emissions for this event originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE-FTS spectra over a wide wavenumber range (750-4400 cm-1), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) and CH3COO2NO2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.

  12. ACE-FTS Observation of a Young Biomass Burning Plume: First Reported Measurements of C2H4, C3H6O, H2CO and PAN by Infrared Occultation from Space

    NASA Technical Reports Server (NTRS)

    Coheur, Pierre-Francois; Herbin, Herve; Clerbaux, Cathy; Hurtmans, Daniel; Wespes, Catherine; Carleer, Michel; Turquety, Solene; Rinsland, Curtis P.; Remedios, John; Hauglustaine, Didier; Boone, Chris D.; Bernath, Peter F.

    2007-01-01

    In the course of our study of the upper tropospheric composition with the infrared 35 Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE FTS), we 36 found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the 37 east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere 38 are performed for this period and they demonstrate that the emissions for this event originated 39 from a nearby forest fire, after which the plume was transported from the source region to the 40 upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE FTS 41 spectra over a wide wavenumber range (750-4400 cm(exp -1), we present in-depth analyses of the 42 chemical composition of this plume in the middle and upper troposphere, focusing on the 43 measurements of weakly absorbing pollutants. For this specific biomass burning event, we 44 report simultaneous observations of an unprecedented number of organic species. 45 Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) 46 and CH3COO2NO2 (perxoxyacetylnitrate, abbreviated as PAN) are the first reported 47 detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the 48 emitted species, we discuss the photochemical age of the plume and also report, whenever 49 possible, the enhancement ratios relative to CO.

  13. The ultraviolet photochemistry of diacetylene - Direct detection of primary products of the metastable C4H2* + C4H2 reaction

    NASA Technical Reports Server (NTRS)

    Bandy, Ralph E.; Lakshminarayan, Chitra; Frost, Rex K.; Zwier, Timothy S.

    1993-01-01

    The products of diacetylene's ultraviolet photochemistry over the 245-220 nm region were directly determined in experiments where C4H2 was excited within a small reaction tube attached to a pulsed nozzle. The products formed in the collisions of C4H2* with C4H2 were subsequently ionized by vacuum UV radiation (at 118 nm) in the ion source of a time-of-flight mass spectrometer. It was found that the reaction of C4H2* with C4H2 produces C6H2 (+C2H2), C8H2 (+2H,H2), and C8H3 (+H), confirming the results of Glicker and Okabe (1987). Under certain conditions, secondary products were observed. Mechanisms for the observed reactions are proposed.

  14. Metal-containing ligands for mixed-metal polymers: novel Cu(II)-Ag(I) mixed-metal coordination polymers generated from [Cu(2-methylpyrazine-5-carboxylate)2(H2O)].3H2O and silver(I) salts.

    PubMed

    Dong, Y B; Smith, M D; zur Loye, H C

    2000-05-01

    One Cu(II)-containing ligand and two Cu(II)-Ag(I) mixed-metal coordination polymers have been synthesized. [Cu(2-methylpyrazine-5-carboxylate)2(H2O)].3H2O (1) was obtained as a molecular complex with two uncoordinated nitrogen donors by the reaction of 2-methylpyrazine-5-carboxylate sodium with CuCl(2).2H2O in water. Compound 1 crystallized in the triclinic space group P1, with a = 10.498(2) A, b = 11.000(2) A, c = 8.1424(16) A, alpha = 98.33(3) degrees, beta = 101.83(3) degrees, gamma = 66.68(3) degrees, and Z = 2. Reactions of 1 with silver(I) salts have been studied. Two Cu(II)-Ag(I) mixed-metal coordination polymers, namely, Ag[Cu(2-methylpyrazine-5-carboxylate)2.(H2O)2](BF4) (2) and Ag[Cu(2-methylpyrazine-5-carboxylate)2.(H2O)2](NO3) (3), have been generated by treating 1 with AgBF4 and AgNO3, respectively. Compound 2 crystallized in the monoclinic space group C2/c, with a = 25.827(5) A, b = 9.6430(19) A, c = 7.4525(15) A, beta = 94.74(3) degrees, and Z = 4. Compound 3 also crystallized in the monoclinic space group C2/c, with a = 25.855(5) A, b = 9.782(2) A, c = 7.1201(14) A, beta = 96.90(3) degrees, and Z = 4. The main structural feature in both 2 and 3 is a zigzag Cu(II)-Ag(I) mixed-metal chain, in which the alternating Cu(II) and Ag(I) centers are linked by 2-methylpyrazine-5-carboxylate spacers. The effect of the nitrate counterion was illustrated by compound 3, in which a novel [Ag+...NO3-] coordination chain has been found which acts as the connector to cross-link the one-dimensional zigzag chains into a three-dimensional network. In addition, an identical interchain O-H...O hydrogen bonding system has been found in both 2 and 3 and has been shown to play a significant role in directing the alignment of the one-dimensional mixed-metal polymer chains in the crystalline state. The magnetic susceptibilities of 2 and 3 were measured and found to follow the Curie law (mu eff = 1.85 for 2 and 1.83 for 3). PMID:11428114

  15. Statistical universal branching ratios for cosmic ray dissociation, photodissociation, and dissociative recombination of the Cn = 2-10, Cn = 2-4H and C3H2 neutral and cationic species

    NASA Astrophysics Data System (ADS)

    Chabot, M.; Tuna, T.; Béroff, K.; Pino, T.; Le Padellec, A.; Désequelles, P.; Martinet, G.; Nguyen-Thi, V. O.; Carpentier, Y.; Le Petit, F.; Roueff, E.; Wakelam, V.

    2010-12-01

    Context. Fragmentation-branching ratios of electronically excited molecular species are of first importance for the modeling of gas phase interstellar chemistry. Despite experimental and theoretical efforts that have been done during the last two decades there is still a strong lack of detailed information on those quantities for many molecules such as Cn, CnH or C3H2. Aims: Our aim is to provide astrochemical databases with more realistic branching ratios for Cn (n = 2 to 10), CnH (n = 2 to 4), and C3H2 molecules that are electronically excited either by dissociative recombination, photodissociation, or cosmic ray processes, when no detailed calculations or measurements exist in literature. Methods: High velocity collision in an inverse kinematics scheme was used to measure the complete fragmentation pattern of electronically excited Cn (n = 2 to 10), CnH (n = 2 to 4), and C3H2 molecules. Branching ratios of dissociation where deduced from those experiments. The full set of branching ratios was used as a new input in chemical models and branching ratio modification effects observed in astrochemical networks that describe the dense cold Taurus Molecular Cloud-1 and the photon dominated Horse Head region. Results: The comparison between the branching ratios obtained in this work and other types of experiments showed a good agreement. It was interpreted as the signature of a statistical behavior of the fragmentation. The branching ratios we obtained lead to an increase of the C3 production together with a larger dispersion of the daughter fragments. The introduction of these new values in the photon dominated region model of the Horse Head nebula increases the abundance of C3 and C3H, but reduces the abundances of the larger Cn and hydrocarbons at a visual extinction AV smaller than 4. Conclusions: We recommend astrochemists to use these new branching ratios. The data published here have been added to the online database KIDA (KInetic Database for Astrochemistry

  16. Identification of ligand efficient, fragment-like hits from an HTS library: structure-based virtual screening and docking investigations of 2H- and 3H-pyrazolo tautomers for Aurora kinase A selectivity.

    PubMed

    Sarvagalla, Sailu; Singh, Vivek Kumar; Ke, Yi-Yu; Shiao, Hui-Yi; Lin, Wen-Hsing; Hsieh, Hsing-Pang; Hsu, John T A; Coumar, Mohane Selvaraj

    2015-01-01

    Furanopyrimidine 1 (IC50 = 273 nM, LE = 0.36, LELP = 10.28) was recently identified by high-throughput screening (HTS) of an in-house library (125,000 compounds) as an Aurora kinase inhibitor. Structure-based hit optimization resulted in lead molecules with in vivo efficacy in a mouse tumour xenograft model, but no oral bioavailability. This is attributed to "molecular obesity", a common problem during hit to lead evolution during which degradation of important molecular properties such as molecular weight (MW) and lipophilicity occurs. This could be effectively tackled by the right choice of hit compounds for optimization. In this regard, ligand efficiency (LE) and ligand efficiency dependent lipophilicity (LELP) indices are more often used to choose fragment-like hits for optimization. To identify hits with appropriate LE, we used a MW cut-off <250, and pyrazole structure to filter HTS library. Next, structure-based virtual screening using software (Libdock and Glide) in the Aurora A crystal structure (PDB ID: 3E5A) was carried out, and the top scoring 18 compounds tested for Aurora A enzyme inhibition. This resulted in the identification of a novel tetrahydro-pyrazolo-isoquinoline hit 7 (IC50 = 852 nM, LE = 0.44, LELP = 8.36) with fragment-like properties suitable for further hit optimization. Moreover, hit 7 was found to be selective for Aurora A (Aurora B IC50 = 35,150 nM) and the possible reasons for selectivity investigated by docking two tautomeric forms (2H- and 3H-pyrazole) of 7 in Auroras A and B (PDB ID: 4AF3) crystal structures. This docking study shows that the major 3H-pyrazole tautomer of 7 binds in Aurora A stronger than in Aurora B. PMID:25344840

  17. The influence of temperature (20-1000 °C) on binary mixtures of solid solutions of CH 3COOLi·2H 2O-MgHPO 4·3H 2O

    NASA Astrophysics Data System (ADS)

    Umbreit, Michał H.; Paukszta, Dominik

    2009-11-01

    Thermally induced phase transitions (20-1000 °C) in the substrates and binary mixtures of CH 3COOLi·2H 2O(1)-MgHPO 4·3H 2O(11) have been analysed. Changes taking place on dehydration and thermal dissociation of binary mixtures prepared with percent molar ratios of 90-10% were studied by differential thermal analysis (TG, DTG, DTA), IR-spectroscopy and WAXS. The above-mentioned substrates changed their structure when heated for 1 h at 500 or 1000 °C. CH 3COOLi·2H 2O(1) (ID: 23-1171) changed the structure at 500 °C to that of Li 2CO 3 (ID: 22-1141), while at 1000 °C the structure was impossible to analyse as the compound reacted both with porcelain and with platinum (crucible materials). MgHPO 4·3H 2O(11) (Newberyite, ID: 35-780, 19-762) changed its structure at 500 °C to amorphous phase and at 1000 °C to Mg 2P 2O 7 (ID: 32-626). The following compounds were assayed in the respective binary mixtures heated at 500 °C for 1 h: 70% (1)-30%(11): LiMgPO 4 (ID: 18-735), MgO (ID: 4-829); 50%(1)-50%(11): LiMgPO 4 (ID: 18-735), Li 3PO 4 (ID: 25-1030); 30%(1)-70%(11): LiMgPO 4 (ID: 32-574); binary mixtures heated at 1000 °C contained the following compounds: 70%(1)-30%(11): LiMgPO 4 (ID: 32-574,18-735), Li 3PO 4 (ID: 15-760,25-1030), MgO (ID: 4-829); 50%(1)-50%(11): LiMgPO 4 (ID: 32-574, 18-735), MgO (ID: 4-829); 30%(1)-70%(11): LiMgPO 4 (ID: 18-735, 32-574), Mg 2P 2O 7 (ID: 22-1152, 8-38), Li 4SiO 4 (37-1472).

  18. Iridium complexes containing mesoionic C donors: selective C(sp3)-H versus C(sp2)-H bond activation, reactivity towards acids and bases, and catalytic oxidation of silanes and water.

    PubMed

    Petronilho, Ana; Woods, James A; Mueller-Bunz, Helge; Bernhard, Stefan; Albrecht, Martin

    2014-11-24

    Metalation of a C2-methylated pyridylimidazolium salt with [IrCp*Cl2]2 affords either an ylidic complex, resulting from C(sp(3))-H bond activation of the C2-bound CH3 group if the metalation is performed in the presence of a base, such as AgO2 or Na2CO3, or a mesoionic complex via cyclometalation and thermally induced heterocyclic C(sp(2))-H bond activation, if the reaction is performed in the absence of a base. Similar cyclometalation and complex formation via C(sp(2))-H bond activation is observed when the heterocyclic ligand precursor consists of the analogous pyridyltriazolium salt, that is, when the metal bonding at the C2 position is blocked by a nitrogen rather than a methyl substituent. Despite the strongly mesoionic character of both the imidazolylidene and the triazolylidene, the former reacts rapidly with D(+) and undergoes isotope exchange at the heterocyclic C5 position, whereas the triazolylidene ligand is stable and only undergoes H/D exchange under basic conditions, where the imidazolylidene is essentially unreactive. The high stability of the Ir-C bond in aqueous solution over a broad pH range was exploited in catalytic water oxidation and silane oxidation. The catalytic hydrosilylation of ketones proceeds with turnover frequencies as high as 6,000 h(-1) with both the imidazolylidene and the triazolylidene system, whereas water oxidation is enhanced by the stronger donor properties of the imidazol-4-ylidene ligands and is more than three times faster than with the triazolylidene analogue. PMID:25302630

  19. Ion-neutral reaction of the C2H2N+ cation with C2H2: An experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Fathi, P.; Geppert, W. D.; Kaiser, A.; Ascenzi, D.

    2016-03-01

    The ion-neutral reactions of the C2H2N+ cation with C2H2 have been investigated using a Guided Ion Beam Mass Spectrometer (GIB-MS). The following ionic products were observed: CH3+, C2H2+, C2H3+, HNC+ /HCN+ , HCNH+, C3H+ , C2N+ , C3H3+, HCCN+ and C4H2N+ . Theoretical calculations have been carried out to propose reaction pathways leading to the observed products. These processes are of relevance for the generation of long chain nitrogen-containing species and they may be of interest for the chemistry of Titan's ionosphere or circumstellar envelopes.

  20. Repetitively pulsed atmospheric pressure discharge treatment of rough polymer surfaces: II. Treatment of micro-beads in He/NH3/H2O and He/O2/H2O mixtures

    NASA Astrophysics Data System (ADS)

    Bhoj, Ananth N.; Kushner, Mark J.

    2008-08-01

    Plasmas are increasingly being used to functionalize the surface of polymers having complex shapes for biomedical applications such as tissue scaffolds and drug delivering micro-beads. The functionalization often requires affixation of amine (NH2) or O-containing groups. In this paper, results are discussed from a two-dimensional computational investigation of the atmospheric pressure plasma functionalization of non-planar and porous surfaces of polypropylene with NHx and O-containing groups. For the former, the discharge is sustained in He/NH3/H2O mixtures in a dielectric barrier-corona configuration. Significant microscopic non-uniformities arise due to competing pathways for reactive gas phase radicals such as OH and NH2, and on the surface by the availability of OH to initiate amine attachment. The treatment of inside surfaces of porous polymer micro-beads placed on an electrode is particularly sensitive to view angles to the discharge and pore size, and is ultimately controlled by the relative rates of radical transport and surface reactions deep into the pores. The functionalization of micro-beads suspended in He/O2/H2O discharges is rapid with comparable treatment of the outer and interior surfaces, but varies with the location of the micro-bead in the discharge volume.

  1. N-Oxide as an Intramolecular Oxidant in the Baeyer-Villiger Oxidation: Synthesis of 2-Alkyl-2H-indazol-3-yl Benzoates and 2-Alkyl-1,2-dihydro-3H-indazol-3-ones.

    PubMed

    Schütznerová, Eva; Krchňák, Viktor

    2016-05-01

    In this study, we describe the intramolecular Baeyer-Villiger oxidation of ketones to esters using N-oxide. 2-Nitro-N-alkyl-N-(2-oxo-2-phenylethyl)benzenesulfonamide compounds are known to undergo base-mediated C-arylation followed by N-N bond formation, producing unstable five-membered ring intermediates that spontaneously dehydrate to indazole oxides. We identified the reaction conditions under which the cyclic intermediate undergoes acid-mediated intramolecular Baeyer-Villiger oxidation of the ketone in which N-oxide serves as the intramolecular oxidizing agent. The solid-phase synthesis plays a critical role in the successful transformation, allowing rapid access to the unstable but Baeyer-Villiger oxidation-prone intermediate. This synthetic route provides practical access to 2-alkyl-2H-indazol-3-yl benzoates and 2-alkyl-1,2-dihydro-3H-indazol-3-ones, which are known privileged structures possessing remarkable diverse pharmacologically relevant activities. PMID:27035416

  2. Characterization, molecular modeling and antimicrobial activity of metal complexes of tridentate Schiff base derived from 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione and 2-aminophenol

    NASA Astrophysics Data System (ADS)

    Adly, Omima M. I.

    Metal complexes of Ni(II), Co(II), Cd(II), VO(IV) and UO2(VI) as well as several Cu(II) salts, including Cl,NO3-,AcO,ClO4- and SO4-2 with a tridentate O2N donor Schiff base ligand (H2L), synthesized by condensation of 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione with 2-aminophenol, were prepared and characterized on the basis of elemental analyses, spectral, magnetic, molar conductance and thermal gravimetric analysis. Square planar, tetrahedral and octahedral geometries have been assigned to the prepared complexes. Molecular parameters of the ligand and its metal complexes have been calculated and correlated with the experimental data, and the changes of bond lengths are linearly correlated with IR data. The antimicrobial activities of the synthesized compounds were tested in vitro against the sensitive organisms Staphylococcus aureus as Gram positive bacteria, Proteus vulgaris as Gram negative bacteria and Candida albicans as fungus strain, and the results are discussed.

  3. Effects of oxygen tension and dextran-shelled/2H,3H-decafluoropentane-cored oxygen-loaded nanodroplets on secretion of gelatinases and their inhibitors in term human placenta.

    PubMed

    Prato, Mauro; Khadjavi, Amina; Magnetto, Chiara; Gulino, Giulia Rossana; Rolfo, Alessandro; Todros, Tullia; Cavalli, Roberta; Guiot, Caterina

    2016-01-01

    Matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) need to be finely modulated in physiological processes. However, oxygen tension influences MMP/TIMP balances, potentially leading to pathology. Intriguingly, new 2H,3H-decafluoropentane-based oxygen-loaded nanodroplets (OLNDs) have proven effective in abrogating hypoxia-dependent dysregulation of MMP and TIMP secretion by single cell populations. This work explored the effects of different oxygen tensions and dextran-shelled OLNDs on MMP/TIMP production in an organized and multicellular tissue (term human placenta). Chorionic villous explants from normal third-trimester pregnancies were incubated with/without OLNDs in 3 or 20% O2. Explants cultured at higher oxygen tension released constitutive proMMP-2, proMMP-9, TIMP-1, and TIMP-2. Hypoxia significantly altered MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios enhancing TIMP-2 and reducing proMMP-2, proMMP-9, and TIMP-1 levels. Intriguingly, OLNDs effectively counteracted the effects of low oxygen tension. Collectively, these data support OLND potential as innovative, nonconventional, and cost-effective tools to counteract hypoxia-dependent dysregulation of MMP/TIMP balances in human tissues. PMID:26523859

  4. Prediction of phase equilibrium for the aqueous systems Rb+, Cs+/Cl-, SO{4/-}-H2O and K+, Cs+/Cl-, SO{4/2-}-H2O at 25°C

    NASA Astrophysics Data System (ADS)

    Hu, B.

    2013-05-01

    The Pitzer ion-interaction extended by Harvic and Weare was applied to predict the solubility isotherms of reciprocal quaternary systems in which mixed crystals are formed. On the basis of data concerning the binary and ternary subsystems, the four components systems Rb+, Cs+/Cl-, SO{4/2-}-H2O, and K+, Cs+/Cl-, SO{4/2-}-H2O were investigated at 25°C.The results of calculation can be used to model salt crystallization during the concentration of brines.

  5. Spectroscopic and structural studies of new mononucleating tetradentate Schiff base metal chelates derived from 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione and 1,3-diaminopropane

    NASA Astrophysics Data System (ADS)

    Adly, Omima M. I.; Taha, Ali; Fahmy, Shery A.

    2015-08-01

    Metal complexes with the general formula Some newly transition metal complexes, [ML(H2O)x(NO3)y], x = 1-2 and y = 0-1, [M = Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Ce(III), Cd(II), Zn(II) or UO2(VI)], L= of the Schiff base (H2L) derived from the reaction of 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione with 1,3-diaminopropane have been prepared and characterized by physical, spectral and analytical data. The structure of the Schiff - base acts as dibasic tetradentate N2O2 for the complexation reaction with Cr(III), Fe(III), Co(II), Cu(II), Ni(II), Ce(III), Cd(II), and UO2(II) ions via phenolates oxygen and nitrogen of azomethine groups. Based on spectral data and magnetic moments, an octahedral geometry may be proposed for the synthesized complexes except cerium(III) complex which has pentagonal bipyramidal arrangement. The low values of the molar conductance indicate non-electrolyte nature of complexes, while 1:1 electrolyte for cerium(III)- and chromium(III)-complexes. The Coats-Redfern equation was used to calculate the kinetic and thermodynamic parameters for the different thermal decomposition steps of some complexes. All the synthesized compounds were tested for in vitro antibacterial activity against some Gram-positive and Gram-negative bacteria, yeast and fungus. Molecular structure of the Schiff base ligand and its complexes were optimized for the proposed structures on the basis of semiempirical PM3 method.

  6. Synthesis, molecular modeling, thermal and spectral studies of metal complexes of hydrazone derived from 5-acetyl-4-hydroxy-2 H-1,3-thiazine-2,6(3 H)-dione and thiosemicarbazide

    NASA Astrophysics Data System (ADS)

    Adly, Omima M. I.

    2011-09-01

    Metal complexes with the general formula [ML(H 2O)(CH 3OH) x]· nH 2O·(CH 3OH) y(NO 3) z [M = Cu(II), Ni(II), Co(II), VO(IV), Cr(III), Cd(II), Zn(II) or UO 2(VI); x = 0-2; y = 0,1; z = 0,1; n = 0-2, 6 and L = hydrazone (H 2L) derived from condensation of thiosemicarbazide with 5-acetyl-4-hydroxy-2 H-1,3-thiazine-2,6(3 H)-dione. The synthesized ligand and its metal complexes have been characterized on the basis of elemental analyses, spectral and magnetic studies as well as thermal gravimetric analysis (TGA). The deprotonated ligand acts as a dibasic tridentate (ONS) via phenolate oxygen, azomethine (C dbnd N), and thiolate (C-S) groups. Copper(II) complex exhibits square planar geometry. Nickel(II), chromium(III) and dioxouranium(VI) complexes exhibit octahedral geometry. Cobalt(II), cadmium(II) and zinc(II) complexes showed tetrahedral geometry, whereas oxovanadium(IV) reveals square pyramidal geometry. Thermal analysis are investigated and showed either three or four thermal decomposition steps. Kinetic parameters ( Ea, A, Δ H, Δ S and Δ G) of the thermal decomposition stages have been evaluated using Coats-Redfern equations. The molecular parameters of the ligand and its metal complexes have been calculated and correlated with the experimental data such as IR and TGA results.

  7. Dynamics of H abstraction from alcohols (CH3OH, C2H5OH and 2-C3H7OH) using velocity map imaging in crossed molecular beams

    SciTech Connect

    Ahmed, M.; Peterka, D.S.; Suits, A.G.

    1999-09-01

    The crossed beam reactions of ground state Cl ({sup 2}P{sub 3/2}) atoms with alcohols (CH{sub 3}OH, C{sub 2}H{sub 5}OH and 2-C{sub 3}H{sub 7}OH) have been studied using the technique of velocity map imaging (VELMI). The corresponding hydroxyalkyl radical was detected via single photon ionization using 157 nm laser light. The double differential cross sections were obtained at collision energies of 8.7 kcal/mol for methanol, 6.0 and 9.7 kcal/mol for ethanol, and 11.9 kcal/mol for 2-propanol. In all cases, the scattering was predominantly in the backward-sideways direction suggesting direct rebound dynamics, with varying amounts of sideways-scattering. In the case of methanol, the angular distributions were predominantly in the sideways-backward direction with respect to the incoming alcohol beam. Scattering was into the backward hemisphere at the lower collision energy for ethanol, with enhancement of sideways scattering with an increase in collision energy. Isoropanol gave scattering predominantly in the backward direction. Coupling between the translational energy and angular distributions was particularly significant for ethanol at the lower collision energy. All of the translational energy distributions peaked at about 6 kcal/mol and on average 30-40% of the available energy was deposited into product translation for all the alcohols studied. These results are contrasted with previous H abstraction studies performed on Cl-hydrocarbon systems. A case is made for the technique of vacuum ultraviolet one-photon ionization in conjunction with VELMI being useful in studying the reaction dynamics for many polyatomic systems.

  8. Layered hybrid organic-inorganic Co(II) alkylphosphonates. Synthesis, crystal structure and magnetism of the first two members of the series: Co[(CH{sub 3}PO{sub 3})(H{sub 2}O)] and Co[(C{sub 2}H{sub 5}PO{sub 3})(H{sub 2}O)

    SciTech Connect

    Bauer, Elvira M.; Bellitto, Carlo . E-mail: carlo.bellitto@ism.cnr.it; Colapietro, Marcello . E-mail: m.colapietro@caspur.it; Ibrahim, Said A.; Mahmoud, Mohamed R.; Portalone, Gustavo; Righini, Guido

    2006-02-15

    Co[(CH{sub 3}PO{sub 3})(H{sub 2}O)] (1) and Co[(C{sub 2}H{sub 5}PO{sub 3})(H{sub 2}O)] (2) were prepared by the hydrothermal method and isolated as blue-violet platelet crystals. They were characterized by X-ray diffraction, FT-IR, TGA-DSC techniques and their magnetic properties studied by a dc-SQUID magnetometer. Compound (1) shows an hybrid layered structure, made of alternating inorganic and organic layers along the a-direction of the unit cell. The inorganic layers contain Co(II) ions six-coordinated by five phosphonate oxygen atoms and one from the water molecule. These layers are separated by bi-layers of methyl groups and van der Waals contacts are established between them. In compound (2), the layered hybrid structure is rather similar to that described for compound (1), but the alternation of the inorganic and organic layers is along the b-direction of the unit cell. The magnetic behavior of (1) and (2) as function of temperature and magnetic field was studied. The compounds obey the Curie-Weiss law at temperatures above 100K, the Curie C, and Weiss {theta} constants for the methyl derivative being C=3.36cm{sup 3}Kmol{sup -1} and {theta}=-53K and for the ethyl derivative C=3.62cm{sup 3}Kmol{sup -1} and {theta}=-75K, respectively. The observed magnetic moments for Co atom at room temperature (i.e. {mu}{sub eff}=5.18 and 5.38 BM, respectively) are higher than those expected for a spin-only value for high spin Co(II) (S=3/2), revealing a substantial orbital contribution to the magnetic moment. The negative values of {theta} are an indication of the presence of antiferromagnetic exchange couplings between the near-neighbors Co(II) ions, within the layers. [Co(C{sub n}H{sub 2n+1}PO{sub 3})(H{sub 2}O)] (n=1,2) are 2D Ising antiferromagnets at low temperatures.

  9. Down-regulation of p-coumaroyl quinate/shikimate 3'-hydroxylase (C3'H) and cinnamate 4-hydroxylase (C4H) genes in the lignin biosynthetic pathway of Eucalyptus urophylla x E. grandis leads to improved sugar release

    SciTech Connect

    Sykes, Robert W.; Gjersing, Erica L.; Foutz, Kirk; Rottmann, William H.; Kuhn, Sean A.; Foster, Cliff E.; Ziebell, Angela; Turner, Geoffrey B.; Decker, Stephen R.; Hinchee, Maud A. W.; Davis, Mark F.

    2015-08-27

    In this study, lignocellulosic materials provide an attractive replacement for food-based crops used to produce ethanol. Understanding the interactions within the cell wall is vital to overcome the highly recalcitrant nature of biomass. One factor imparting plant cell wall recalcitrance is lignin, which can be manipulated by making changes in the lignin biosynthetic pathway. In this study, eucalyptus down-regulated in expression of cinnamate 4-hydroxylase (C4H, EC 1.14.13.11) or p-coumaroyl quinate/shikimate 3'-hydroxylase (C3'H, EC 1.14.13.36) were evaluated for cell wall composition and reduced recalcitrance.

  10. Synthesis and Biological Activity of Manganese (II) Complexes of Phthalic and Isophthalic Acid: X-Ray Crystal Structures of [Mn(ph)(Phen)(2)(H(2)O)]. 4H(2)O, [Mn(Phen)(2)(H(2)O)(2)](2)(Isoph)(2)(Phen). 12H(2)O and {[Mn(Isoph)(bipy)](4). 2.75biby}(n)(phH(2) = Phthalic Acid; isoph = Isophthalic Acid; phen = 1,10-Phenanthroline; bipy = 2,2-Bipyridine).

    PubMed

    Devereux, M; McCann, M; Leon, V; Geraghty, M; McKee, V; Wikaira, J

    2000-01-01

    Manganese(II) acetate reacts with phthalic acid (phH(2)) to give [Mn(ph)].0.5H(2)O (1). Reaction of 1 with 1,10-phenanthroline produces [Mn(ph)(phen)].2H(2)O (2) and [Mn(ph)(phen)(2)(H(2)O)].4H(2)O (3). Reaction of isophthalic acid (isophH(2)) with manganese(II) acetate results in the formation of [Mn(isoph)].2H(2)O (4). The addition of the N,N-donor ligands 1,10-phenanthroline or 2,2'-bipyridine to 4 leads to the formation of [Mn(2) (isoph)(2)(phen)(3))].4H(2)O (5), [(Mn(phen)(2)(H(2)O)(2)](2)(isoph)(2)(phen).12H(2)O (6) and {[Mn(isoph)(bipy)](4).2.75 biby}(n) (7), respectively. Molecular structures of 3, 6 and 7 were determined crystallographically. In 3 the phthalate ligand is bound to the manganese via just one of its carboxylate groups in a monodentate mode with the remaining coordination sites filled by four phenanthroline nitrogen and one water oxygen atoms. In 6 the isophthalates are uncoordinated with the octahedral manganese center ligated by two phenanthrolines and two waters. In 7 the Isophthalate ligands act as bridges resulting in a polymeric structure. One of the carboxylate groups is chelating a single manganese with the other binding two metal centres in a bridging bidentate mode. The phthalate and isophthalate complexes, the metal free ligands and a number of simple manganes salts were each tested for their ability, to inhibit the growth of Candida albicans. Only the "metal free" 1,10-phenanthroline and its manganese complexes were found to be active. PMID:18475957

  11. Synthesis and Biological Activity of Manganese (II) Complexes of Phthalic and Isophthalic Acid: X-Ray Crystal Structures of [Mn(ph)(Phen)2(H2O)]· 4H2O, [Mn(Phen)2(H2O)2]2(Isoph)2(Phen)· 12H2O and {[Mn(Isoph)(bipy)]4· 2.75biby}n(phH2 = Phthalic Acid; isoph = Isophthalic Acid; phen = 1,10-Phenanthroline; bipy = 2,2-Bipyridine)

    PubMed Central

    McCann, Malachy; Leon, Vanessa; Geraghty, Majella; McKee, Vickie; Wikaira, Jan

    2000-01-01

    Manganese(II) acetate reacts with phthalic acid (phH2) to give [Mn(ph)]·0.5H2O (1). Reaction of 1 with 1,10-phenanthroline produces [Mn(ph)(phen)]·2H2O (2) and [Mn(ph)(phen)2(H2O)]·4H2O (3). Reaction of isophthalic acid (isophH2) with manganese(II) acetate results in the formation of [Mn(isoph)]·2H2O (4). The addition of the N,N-donor ligands 1,10-phenanthroline or 2,2'-bipyridine to 4 leads to the formation of [Mn2 (isoph)2(phen)3)]·4H2O (5), [(Mn(phen)2(H2O)2]2(isoph)2(phen)·12H2O (6) and {[Mn(isoph)(bipy)]4·2.75 biby}n (7), respectively. Molecular structures of 3, 6 and 7 were determined crystallographically. In 3 the phthalate ligand is bound to the manganese via just one of its carboxylate groups in a monodentate mode with the remaining coordination sites filled by four phenanthroline nitrogen and one water oxygen atoms. In 6 the isophthalates are uncoordinated with the octahedral manganese center ligated by two phenanthrolines and two waters. In 7 the Isophthalate ligands act as bridges resulting in a polymeric structure. One of the carboxylate groups is chelating a single manganese with the other binding two metal centres in a bridging bidentate mode. The phthalate and isophthalate complexes, the metal free ligands and a number of simple manganes salts were each tested for their ability, to inhibit the growth of Candida albicans. Only the “metal free” 1,10-phenanthroline and its manganese complexes were found to be active. PMID:18475957

  12. Hydrogen bond strength in some beryllium salts, BeXO 4·4H 2O and Me 2Be(XO 4) 2·2H 2O (X = S, Se; Me = K, Rb): Correlation of structural data and infrared spectra

    NASA Astrophysics Data System (ADS)

    Georgiev, M.; Wildner, M.; Stoilova, D.

    2009-08-01

    Infrared spectra of the title compounds are presented and discussed in the regions of the uncoupled O-D stretches of matrix-isolated HDO molecules (isotopically dilute samples). The strengths of the hydrogen bonds are analyzed in terms of the respective O w⋯O bond distances, the Be-OH 2 interactions (synergetic effect), the proton acceptor capabilities of the sulfate and selenate oxygen atoms as deduced from Brown's bond valence sums of the oxygen atoms, the anti-cooperative effect (proton acceptor and proton donor competitive effect). The infrared spectroscopic experiments reveal that comparatively strong hydrogen bonds are formed in the compounds under study, analogical to other hydrated beryllium salts owing to the large ionic potential of the small Be 2+ ions. The wavenumbers of νOD show that the water molecules in BeSO 4·4H 2O and in the double salts are strongly energetically distorted, i.e. their local symmetries deviate remarkably from the C2 v molecular symmetry (for example, Δ ν have values of 74 and 36 cm -1 for H 2O(1) and H 2O(2) in K 2Be(SO 4) 2·2H 2O, and 119 cm -1 in BeSO 4·4H 2O). The hydrogen bonds in K 2Be(SeO 4) 2·2H 2O are stronger than those in K 2Be(SO 4) 2·2H 2O due to the stronger proton acceptor capability of the SeO 42- ions. The proton donor strengths of the water molecules in K 2Be(SO 4) 2·2H 2O and K 2Be(SeO 4) 2·2H 2O are greater than those of the water molecules in BeSO 4·4H 2O and BeSeO 4·4H 2O (i.e. larger deviations from Mikenda's curve) due to the different compositions of the respective beryllium tetrahedra-Be(XO 4) 2(H 2O) 2 in the double salts and Be(H 2O) 4 in the simple ones (proton donor competitive effect). The intramolecular O-H bond lengths are derived from the νOD vs. rOH correlation curve [H.D. Lutz, C. Jung, J. Mol. Struct. 404 (1997) 63].

  13. Energetics of phosphate frameworks containing zinc and cobalt: NaZnPO{sub 4}, NaH(ZnPO{sub 4}){sub 2}, NaZnPO{sub 4}.H{sub 2}O, NaZnPO{sub 4}.4/3 H{sub 2}O, and NaCo{sub x}Zn{sub 1-x}PO{sub 4}.4/3 H{sub 2}O

    SciTech Connect

    Le, So-Nhu; Navrotsky, Alexandra

    2007-09-15

    Differential scanning calorimetry and high temperature oxide melt solution calorimetry were used to study the enthalpy of the {alpha}-{beta} phase transformation of NaZnPO{sub 4} and enthalpies of formation of {alpha}-NaZnPO{sub 4}, NaH(ZnPO{sub 4}){sub 2}, NaZnPO{sub 4}.H{sub 2}O, and NaCo{sub x}Zn{sub 1-x}PO{sub 4}.4/3 H{sub 2}O (x=0, 0.1, 0.2, 0.3). The enthalpies of formation from the oxides of cobalt substituted in NaZnPO{sub 4}.4/3 H{sub 2}O do not depend on cobalt content, confirming similar acid-base interactions for Zn-PO{sub 4} and Co-PO{sub 4}. While water molecules stabilize zinc phosphate frameworks through solvating a cation or forming extra hydrogen bonds, the partial substitution of water for sodium oxide to form NaH(ZnPO{sub 4}){sub 2} represents the formation of an acidic compound with weaker acid-base interactions and less exothermic enthalpy of formation from oxides than Na{sub 2}(ZnPO{sub 4}){sub 2}. - Graphical abstract: Relative stability of NaZnPO{sub 4} dense phases, open frameworks, and hydrated frameworks. Enthalpy of interaction between water and NaZnPO{sub 4} frameworks is presented by reaction: NaZnPO{sub 4} (cr, open framework) + nH{sub 2}O (l) {yields} NaZnPO{sub 4}.nH{sub 2}O (cr, hydrated framework)

  14. Explicit reduced reaction models for ignition, flame propagation, and extinction of C{sub 2}H{sub 4}/CH{sub 4}/H{sub 2} and air systems

    SciTech Connect

    Zambon, A.C.; Chelliah, H.K.

    2007-07-15

    Large-scale simulations of multidimensional unsteady reacting flows with detailed chemistry and transport can be computationally extremely intensive even on distributed computing architectures. With the development of computationally efficient reduced chemical kinetic models, the smaller number of scalar variables to be integrated can lead to a significant reduction in the computational time required for the simulation with limited loss of accuracy in the results. A general MATLAB-based automated procedure for the development of reduced reaction models is presented. Based on the application of the quasi-steady-state (QSS) approximation for certain chemical species and on the elimination of selected fast elementary reactions, any complex starting reaction mechanism (detailed or skeletal) can be reduced with minimal human intervention. A key feature of the reduction procedure is the decoupling of the QSS species appearing in the QSS algebraic relations, enabling the explicit solution of the QSS species concentrations, which are needed for the evaluation of the elementary reaction rates. In contrast, previous approaches mainly relied on an implicit solution, requiring computationally intensive inner iterations. The automated procedure is first tested with the generation of an implicit 5-step reduced reaction model for CH{sub 4}/air flame propagation. Next, two explicit robust reduced reaction models based on ignition data (18-step) and on flame propagation data (15-step) are systematically developed and extensively validated for ignition delay time, flame propagation, and extinction predictions of C{sub 2}H{sub 4}/air, CH{sub 4}/air, and H{sub 2}/air systems over a wide range of equivalence ratios, initial temperatures, pressures, and strain rates. In order to assess the computational advantages of the explicit reduced reaction models, comparisons of the computational time required to evaluate the chemical source terms as well as for the integration of unsteady

  15. Large hydrogen-bonded pre-nucleation (HSO4-)(H2SO4)m(H2O)k and (HSO4-)(NH3)(H2SO4)m(H2O)k clusters in the earth's atmosphere.

    PubMed

    Herb, Jason; Xu, Yisheng; Yu, Fangqun; Nadykto, A B

    2013-01-10

    The importance of pre-nucleation cluster stability as the key parameter controlling nucleation of atmospheric airborne ions is well-established. In this Article, large ternary ionic (HSO(4)(-))(H(2)SO(4))(m)(NH(3))(H(2)O)(n) clusters have been studied using Density Functional Theory (DFT) and composite ab initio methods. Twenty classes of clusters have been investigated, and thermochemical properties of common atmospheric (HSO(4)(-))(H(2)SO(4))(m)(NH(3))(0)(H(2)O)(k) and (HSO(4)(-))(H(2)SO(4))(m)(NH(3))(1)(H(2)O)(n) clusters (with m, k, and n up to 3) have been obtained. A large amount of new themochemical and structural data ready-to-use for constraining kinetic nucleation models has been reported. We have performed a comprehensive thermochemical analysis of the obtained data and have investigated the impacts of ammonia and negatively charged bisulfate ion on stability of binary clusters in some detail. The comparison of theoretical predictions and experiments shows that the PW91PW91/6-311++G(3df,3pd) results are in very good agreement with both experimental data and high level ab initio CCSD(T)/CBS values and suggest that the PW91PW91/6-311++G(3df,3pd) method is a viable alternative to higher level ab initio methods in studying large pre-nucleation clusters, for which the higher level computations are prohibitively expensive. The uncertainties in both theory and experiments have been investigated, and possible ways of their reduction have been proposed. PMID:23136922

  16. 4-H and Iowa.

    ERIC Educational Resources Information Center

    Gore, Deborah, Ed.

    1988-01-01

    This issue focuses on Iowa's role in the historical development of the 4-H youth program. "Roots in Iowa" and "Jessie Field Shambaugh: The Mother of 4-H" (J. Friedel) describes the rural Iowan roots of the 4-H program, which today is located in 80 different countries, and give the story of its founder. Jessie Shambaugh, a rural Iowa teacher and…

  17. Contributions of excited {sup 6}Li and {sup 7}Li nuclei to the production of {sup 4}He+{sup 2}H and {sup 4}He+{sup 3}H systems in {sup 16}O{sub p} collisions at a momentum of 3.25 GeV/c per nucleon

    SciTech Connect

    Olimov, K.; Glagolev, V. V.; Gulamov, K. G.; Lutpullaev, S. L.; Kurbanov, A. R.; Olimov, A. K.; Petrov, V. I.; Yuldashev, A. A.

    2013-07-15

    New experimental data on the cross sections for the yield of excited {sup 6}Li* and {sup 7}Li* nuclei and on their contributions to the production of {sup 4}He + {sup 2}H and {sup 4}He+{sup 3}H light dinuclear systems in {sup 16}O{sub p} collisions at a momentumof 3.25 A GeV/c per nucleon are presented.

  18. Isochoric p-{rho}-T and heat capacity C{sub v} measurements on {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}, x {approx} 0.7, 0.3{r_brace} from 200 to 400 K at pressures to 35 MPa

    SciTech Connect

    Duarte-Garza, H.A.; Magee, J.W.

    1999-09-01

    The p-{rho}-T relationships and constant volume heat capacity C{sub v} were measured for binary hydrocarbon mixtures containing propane (C{sub 3}H{sub 8}) and isobutane (i-C{sub 4}H{sub 10}). Temperatures ranged from 200 K to 400 K for p-{rho}-T and from 203 K to 342 K for C{sub v} with pressures up to 35 MPa for both measurements. Measurements of p-{rho}-T and C{sub v} were conducted on liquid samples with the mole fraction compositions {l_brace}xC{sub 3}H{sub 8} + (1 {minus} x)i-C{sub 4}H{sub 10}{r_brace} for x = 0.7006 and x = 0.2979. Determinations of saturated-liquid densities were made by extrapolating each isochore to the saturated-liquid pressure and determining the temperature and density at the intersection. Published p-{rho}-T data are in good agreement with this study. For the p-{rho}-T apparatus, the uncertainty of the temperature is 0.03 K, and for pressure it is 0.01% at p > 3 MPa and 0.05% at p < 3 MPa. The principal source of uncertainty in density is the cell volume ({approximately}28.5 cm{sup 3}) with a standard uncertainty of 0.003 cm{sup 3}. When all components of experimental uncertainty are considered, the expanded relative uncertainty (with a coverage factor {kappa} = 2 and thus a two-standard-deviation estimate) of the density measurements is estimated to be 0.05%. For the C{sub v} apparatus, the uncertainty is 0.002 K for the temperature rise and 0.2% for the change-of-volume work, which is the principal source of uncertainty. The expanded relative uncertainty of the heat capacity measurements is estimated to be 0.7%. Hydrocarbon mixtures are considered to be leading candidates to replace chlorofluorocarbon refrigerants, which will be phased out under the terms of the Montreal Protocol.

  19. Structural and computational characterization of 4‧,4‧,6‧,6‧-tetrachloro-3-(2-methoxyethyl)-3H,4H-spiro-1,3,2-benzoxaza phosphinine-2,2‧- [1,3,5,2,4,6] triazatriphosphinine

    NASA Astrophysics Data System (ADS)

    Işıklan, Muhammet; Yıldırım, Erdem Kamil; Atiş, Murat; Sonkaya, Ömer; Çoşut, Bünyemin

    2016-08-01

    In this study a new monospirocyclic phosphazene derivative, 4‧,4‧,6‧,6‧-tetrachloro-3-(2-methoxyethyl)-3H,4H-spiro [1,3,2-benzoxazaphosphinine-2,2‧- [1,3,5,2,4,6] triazatriphosphinine] (SP1) was synthesized from the reaction of hexachlorocyclotriphosphazene (N3P3Cl6) with N/O donor-type, 2-{[(2-Metoxyethyl) amino]methyl}phenol. The structural investigations of the compound were verified by elemental analyses, MS, FTIR, 1H, 13C, 31P NMR spectroscopy and the single crystal X-ray diffraction analysis. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method (DFT) using 6-311++G (d, p) basis set. The complete assignments of all vibrational modes were performed on the basis of the total energy distributions (TED). Isotropic chemical shifts (31P, 1H and 13C NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. Theoretical calculations of bond parameters, harmonic vibration frequencies and nuclear magnetic resonance are in good agreement with experimental results. The electrophilic and nucleophilic attack centers in SP1 were predicted with the local softness values (sk+, and sk-) of individual atoms and it is confirmed that P atoms of the PCl2 groups are nucleophilic attack centers.

  20. Synthesis and structure of a heterometallic cluster with a novel layered structure: (W(CO)/sub 5/SnClFe(CO)/sub 4/)/sub 2/(Na/sub 2/((C/sub 2/H/sub 5/)/sub 2/O)/sub 4/(C/sub 4/H/sub 8/O/sub 2/))

    SciTech Connect

    Balch, A.L.; Olmstead, M.M.; Oram, D.P.

    1988-11-16

    In an attempt to create an example of substituent-free complex derived from Sn(II), the reaction between (OC)/sub 5/WSnCl/sub 2/(tetrahydrofuran) and Fe(CO)/sub 4//sup /minus/2/ was studied. Instead of the expected compound (OC)/sub 5/WSn=Fe(CO)/sub 4/, the dimer (W(CO)/sub 5/SnClFe(CO)/sub 4/)/sub 2/Na/sub 2/(C/sub 2/H/sub 5/)O/sub 4/(C/sub 4/H/sub 8/O/sub 2/) was the product formed. The properties and structure of this dimer are reported herein. 17 refs., 3 figs., 3 tabs.

  1. Holo- and hemidirected lead(II) in the polymeric [Pb(4)(mu-3,4-TDTA)2(H2O)2]*4H2O complex. N,N,N',N'-tetraacetate ligands derived from o-phenylenediamines as sequestering agents for lead(II).

    PubMed

    Sanchiz, Joaquín; Esparza, Pedro; Villagra, Diego; Domínguez, Sixto; Mederos, Alfredo; Brito, Felipe; Araujo, Lorena; Sánchez, Agustin; Arrieta, Juan Manuel

    2002-11-18

    The coordinating ability of the ligands 3,4-toluenediamine-N,N,N',N'-tetraacetate (3,4-TDTA), o-phenylenediamine-N,N,N',N'-tetraacetate (o-PhDTA), and 4-chloro-1,2-phenylenediamine-N,N,N',N'-tetraacetate (4-Cl-o-PhDTA) (H4L acids) toward lead(II) is studied by potentiometry (25 degrees C, I = 0.5 mol x dm(-3) in NaClO4), UV-vis spectrophotometry, and 207Pb NMR spectrometry. The stability constants of the complex species formed were determined. X-ray diffraction structural analysis of the complex [Pb4(mu-3,4-TDTA)4(H2O)2]*4H2O (1) revealed that 1 has a 2-D structure. The layers are built up by the polymerization of centrosymmetric [Pb4L2(H2O)2] tetranuclear units. The neutral layers have the aromatic rings of the ligands pointing to the periphery, whereas the metallic ions are located in the central part of the layers. In compound 1, two types of six-coordinate lead(II) environments are produced. The Pb(1) is coordinated to two nitrogen atoms and four carboxylate oxygens from the ligand, whereas Pb(2) has an O6 trigonally distorted octahedral surrounding. The lead(II) ion is surrounded by five carboxylate oxygens and a water molecule. The carboxylate oxygens belong to four different ligands that are also joined to four other Pb(1) ions. The selective uptake of lead(II) was analyzed by means of chemical speciation diagrams as well as the so-called conditional or effective formation constants K(Pb)eff. The results indicate that, in competition with other ligands that are strong complexing agents for lead(II), our ligands are better sequestering agents in acidic media. PMID:12425632

  2. U(IV)/Ln(III) mixed site in polymetallic oxalato complexes. Part III: Structure of Na[Yb(C 2O 4) 2(H 2O)]·3H 2O and the derived quadratic series (NH 4+) 1-x[ Ln1-xU x (C 2O 4) 2(H 2O)]·(3+ x) H 2O, Ln=Y, Pr-Sm, Gd, Tb

    NASA Astrophysics Data System (ADS)

    Chapelet-Arab, B.; Duvieubourg, L.; Nowogrocki, G.; Abraham, F.; Grandjean, S.

    2006-12-01

    Single crystals of a new sodium ytterbium oxalate Na[Yb(C 2O 4) 2(H 2O)]·3H 2O ( 1) and six mixed lanthanide (III)-uranium (IV) oxalates (NH 4+) 1-x[ Ln1-xU x (C 2O 4) 2(H 2O)]·(3+ x) H 2O, Ln=Y, x=0.47 ( 2), Ln=Pr, x=0.42 ( 3), Ln=Nd, x=0.60 ( 4), Ln=Sm, x=0.55 ( 5), Ln=Gd, x=0.25 ( 6) and Ln=Tb, x=0.52 ( 7) have been grown using slow diffusion through silica gels. The crystal structures of all the compounds have been determined by single-crystal X-ray diffraction. For compound 1 the symmetry is monoclinic, space group Pc, cell dimensions a=8.559(2) Å, b=8.564(2) Å, c=14.938(3) Å, β=103.062(3), Z=4. The structure of 1 is isotypic with Na[Y(C 2O 4) 2(H 2O)]·3H 2O and consists of layers formed by four-membered rings of Yb connected through oxalate ions. The ytterbium atom is nine-coordinated by oxygen from four bis-bidentate oxalate ligands and one water molecule which alternate up and down the layer. Na + ions and supplementary water molecules are located between the layers. The six mixed lanthanide (III)-uranium (IV) oxalates, 2- 7, are isotypic, the symmetry is tetragonal, space group P4/ n, the unit cell parameters are in the range 8.7239(12)-8.9116(6) and 7.854(2)-7.9487(9) Å for a and c, respectively, Z=2. The structure of the six compounds is built from the same two-dimensional arrangement of alternating metallic and oxalate ions forming four-membered rings. The layers are similar to that observed in 1 and the mixed Ln(III)/U(IV) oxalate layers are obtained by partial substitution of Ln(III) by U(IV) in a nine-coordinated site, the charge surplus being compensated by removal of monovalent cations in the interlayer space. The ammonium ions and the water molecules are disordered in the same crystallographic site. Thus these compounds form the third series of mixed lanthanide (III)-uranium (IV) oxalates, the tetragonal one, that completes the two others previously reported, the hexagonal and the triclinic series.

  3. Diffuse reflection infrared Fourier transform (DRIFT) spectra and high-temperature DRIFT spectra of beta-Ni(IO3)2.4H2O, Ni(IO3)2.2H2O, Mg(OH)2, and Zn(OH)F: novel embedding materials.

    PubMed

    Pracht, G; Weckler, B; Lutz, H D

    2003-10-01

    Diffuse reflection infrared Fourier transform (DRIFT) spectra of the hydroxides Mg(OH)2 and Zn(OH)F and the iodate hydrates beta-Ni(IO3)2.4H2O and Ni(IO3)2.2H2O have been recorded at ambient and high temperature. Spectra without shifts of the band maxima compared to those of conventional infrared transmission spectra and without inversion of the bands were obtained by dilution of the compounds to about 2-10% with an appropriate embedding material. alpha-Al2O3, TiO2, ZrO2, PbF2, MgO, BaO, ZnO, Na2SiO3, SiO2 (aerosil), and powdered copper, aluminum, and magnesium were tested as diluents for hydrates and hydroxides, especially at elevated temperatures, as alternatives for the commonly used KBr. Thus, alpha-Al2O3, PbF2, and powdered copper were established as the most favorable diluents. Using these novel embedding materials, high-temperature DRIFT spectra are obtainable at temperatures not accessible with KBr discs. Dehydration and decomposition of the iodate hydrates under study were shown by change or disappearance of the respective water bands. PMID:14639754

  4. Synthesis and photosensitivity characterizations of 9-(6-bromo-4-oxo-4H-chromen-3-yl)-3,4,6,7-tetrahydro-3,3,6,6-tetramethyl-2H-xanthene-1,8-(5H,9H)-dione(BOCTTX)

    NASA Astrophysics Data System (ADS)

    Ibrahim, Magdy A.; Farag, A. A. M.; Roushdy, N.; El-Gohary, Nasser M.

    2016-02-01

    Condensation reaction of 6-bromochromone-3-carboxaldehyde (1) with dimedone afforded 9-(6-bromo-4-oxo-4H-chromen-3-yl)-3,4,6,7-tetrahydro-3,3,6,6-tetramethyl-2H-xanthene-1,8-(5H,9H)-dione (3, BOCTTX). Structure of BOCTTX was deduced based on its correct elemental analysis and spectral data (IR, 1H NMR, 13C NMR and mass spectra). Thin films of BOCTTX were prepared in this study by using spin coating technique. X-ray diffraction, scanning electron microscope analysis were studied for study the crystal and morphology characterization of BOCTTX. The results indicate that BOCTTX has a polycrystalline nature with monoclinic structure. From differential scanning calorimetry, BOCTTX is found to be thermally stable up to 583 K and the chemical structure plays an important role in the thermal decomposition process. The optical absorption of the film was studied in the UV-Vis spectral range and the value of two allowed energy gaps of 2.2 and 3.3 eV. Current-voltage characteristics of BOCTTX based devices were studied in dark and under various illumination intensities in the range 20-100 mW/cm2. Electrical and photoelectrical parameters were studied as a function of light intensity. The obtained results exhibits photoconductivity cauterization and suggest that the diode can be used as a photodiode in optoelectronic sensor application.

  5. Metal-ligand interaction of lanthanides with coumarin derivatives. Part I. Complexation of 3-(1-aminoethylidene)-2H-chromene-2,4(3H)-dione with La(III), Ce(III), Nd(III) and Ho(III).

    PubMed

    Swiatek, Mirosława; Kufelnicki, Aleksander

    2012-01-01

    Solutions of lanthanum(III), cerium(III), neodymium(III) and holmium(III) nitrates with 3-(1-aminoethylidene)-2H-chromene-2,4(3H)-dione (1) in 10% v/v dioxane-water medium were used. Coordination modes of 1 with the selected lanthanides have been examined. Hydroxo-complexes with deprotonated water molecules from the inner coordination sphere have been stated in basic medium. Stability constants of the forming complex species were determined by potentiometric titrations using Superquad and Hyperquad2003 programs. The most stable complexes are formed with La(III). The UV-Vis spectra of the Nd(III)-1 system confirmed the L:M = 1:1 stoichiometry evaluated potentiometrically. PMID:23285658

  6. Astronomical identification of the C3H radical

    NASA Astrophysics Data System (ADS)

    Thaddeus, P.; Gottlieb, C. A.; Hjalmarson, A.; Johansson, L. E. B.; Irvine, W. M.; Friberg, P.; Linke, R. A.

    1985-07-01

    The C3H radical has been identified in the millimeter-wave spectra of IRC +10216 and TMC-1. In IRC +10216, four rotational transitions have been observed, three in the lower fine-structure ladder (2Pi1/2) and one in the upper (2Pi3/2), each a resolved or partially resolved lambda-doublet. In TMC-1, both lambda components of the lowest lying 3/2-1/2 transition of the 2Pi1/2 ladder have been observed, each with well-resolved hfs. In IRC +10216, the excitation of C3H is similar to that of SiCC: the rotational temperature Trot within the 2Pi1/2 ladder is low (8.5 K), because of rapid radiative decay, while Trot across the ladders is high (about 52 K), because interconnecting far-IR radiative transitions are only weakly permitted. The column density of C3H in IRC +10216 averaged over the estimated source diameter of 84 arcsec is 2.8 x 10 to the 13th/sq cm, an order of magnitude less than that of C2H and C4H.

  7. Calculational and Experimental Investigations of the Pressure Effects on Radical - Radical Cross Combinations Reactions: C2H5 + C2H3

    NASA Technical Reports Server (NTRS)

    Fahr, Askar; Halpern, Joshua B.; Tardy, Dwight C.

    2007-01-01

    Pressure-dependent product yields have been experimentally determined for the cross-radical reaction C2H5 + C2H3. These results have been extended by calculations. It is shown that the chemically activated combination adduct, 1-C4H8*, is either stabilized by bimolecular collisions or subject to a variety of unimolecular reactions including cyclizations and decompositions. Therefore the "apparent" combination/disproportionation ratio exhibits a complex pressure dependence. The experimental studies were performed at 298 K and at selected pressures between about 4 Torr (0.5 kPa) and 760 Torr (101 kPa). Ethyl and vinyl radicals were simultaneously produced by 193 nm excimer laser photolysis of C2H5COC2H3 or photolysis of C2H3Br and C2H5COC2H5. Gas chromatograph/mass spectrometry/flame ionization detection (GC/MS/FID) were used to identify and quantify the final reaction products. The major combination reactions at pressures between 500 (66.5 kPa) and 760 Torr are (1c) C2H5 + C2H3 yields 1-butene, (2c) C2H5 + C2H5 yields n-butane, and (3c) C2H3 + C2H3 yields 1,3-butadiene. The major products of the disproportionation reactions are ethane, ethylene, and acetylene. At moderate and lower pressures, secondary products, including propene, propane, isobutene, 2-butene (cis and trans), 1-pentene, 1,4-pentadiene, and 1,5-hexadiene are also observed. Two isomers of C4H6, cyclobutene and/or 1,2-butadiene, were also among the likely products. The pressure-dependent yield of the cross-combination product, 1-butene, was compared to the yield of n-butane, the combination product of reaction (2c), which was found to be independent of pressure over the range of this study. The [ 1-C4H8]/[C4H10] ratio was reduced from approx.1.2 at 760 Torr (101 kPa) to approx.0.5 at 100 Torr (13.3 kPa) and approx.0.1 at pressures lower than about 5 Torr (approx.0.7 kPa). Electronic structure and RRKM calculations were used to simulate both unimolecular and bimolecular processes. The relative importance

  8. Thermochemistry and dissociation dynamics of state-selected C/sub 4/H/sub 8/O/sub 2//sup +/ ions. 2. Butanoic acid

    SciTech Connect

    Butler, J.J.; Fraser-Monteiro, M.L.; Fraser-Monteiro, L.; Baer, T.; Hass, J.R.

    1982-01-01

    Photoionization efficiency curves and appearance energies for C/sub 4/H/sub 8/O/sub 2//sup +/, C/sub 3/H/sub 5/O/sub 2//sup +/, C/sub 2/H/sub 7/O/sup +/, C/sub 2/H/sub 4/O/sub 2//sup +/, C/sub 3/H/sub 7//sup +/, C/sub 3/H/sub 6//sup +/, C/sub 2/H/sub 5//sup +/, and C/sub 2/H/sub 4//sup +/ from butanoic acid have been obtained. Structures and heats of formation for some of the ions are proposed. No evidence for metastable C/sub 4/H/sub 8/O/sub 2//sup +/ ions forming C/sub 3/H/sub 5/O/sub 2//sup +/ (m/e 73) and C/sub 2/H/sub 4/O/sub 2//sup +/ (m/e 60) was found in the photoion-photoelectron coincidence (PIPECO) results. An upper limit to the parent ion lifetimes is 0.1 ..mu..s. In constrast, to the photoionization results, electron impact ionization produces strong C/sub 4/H/sub 8/O/sub 2//sup +/ metastables with lifetimes in the 10-..mu..s range. This paradox can be resolved by postulating that photoionization produces only rapidly dissociating butanoic acid ions, while a long-lived isomerized structure (or structures), such as the enol form are accessible by electron impact.

  9. Experimental ion mobility measurements in Ar-C2H6 mixtures

    NASA Astrophysics Data System (ADS)

    Cortez, A. F. V.; Garcia, A. N. C.; Neves, P. N. B.; Santos, F. P.; Borges, F. I. G. M.; Barata, J. A. S.; Conde, C. A. N.

    2013-12-01

    In this paper we present the experimental results for the mobility of ions in argon-ethane gaseous mixtures (Ar-C2H6) for pressures ranging from 6 to 10 Torr and for reduced electric fields in the 10 Td to 25 Td range, at room temperature. For Ar concentrations below 80% two peaks were observed in the time of arrival spectra which were attributed to ion species with 3-carbons (C3H7+, C3H8+ and C3H9+) and with 4-carbons (which includes C4H7+, C4H9+, C4H10+ and C4H12+ ions). For Ar concentrations above 80% a third peak appears, which may belong to C5H11+. The time of arrival spectra for Ar concentrations of 80%, 85%, 90% and 95% are displayed in the present paper as well as the reduced mobilities determined from the peaks observed for a typical reduced electric field used in gaseous detectors (E/N = 15 Td).

  10. Synthesis, characterization and magnetic property of a new 3D iron phosphite: |C{sub 4}N{sub 3}H{sub 14}|[Fe{sub 3}(HPO{sub 3}){sub 4}F{sub 2}(H{sub 2}O){sub 2}] with intersecting channels

    SciTech Connect

    Qiao Jian; Zhang Lirong; Yu Yang; Li Guanghua; Jiang Tianchan; Huo Qisheng; Liu Yunling

    2009-07-15

    A new open-framework iron (III) phosphite |C{sub 4}N{sub 3}H{sub 14}|[Fe{sub 3}(HPO{sub 3}){sub 4}F{sub 2}(H{sub 2}O){sub 2}] has been solvothermally synthesized by using diethylenetriamine (DETA) as the structure-directing agent. Single-crystal X-ray diffraction analysis reveals that the compound crystallizes in the monoclinic space group C2/c having unit cell parameters a=12.877(3) A, b=12.170(2) A, c=12.159(2) A, beta=93.99(3){sup o}, V=1900.9(7) A{sup 3}, and Z=4 with R{sub 1}=0.0447, wR{sub 2}=0.0958. The complex structure consists of HPO{sub 3} pseudo-tetrahedra and {l_brace}Fe{sub 3}O{sub 14}F{sub 2}{r_brace} trimer building units. The assembly of these building units generates 3D inorganic framework with intersecting 6-, 8-, and 10-ring channels. The DETA cations are located in the 10-ring channels linked by hydrogen bonds. The Moessbauer spectrum shows that there exhibit two crystallographically independent iron (III) atoms. And the magnetic investigation shows the presence of antiferromagnetic interactions. Further characterization of the title compound was performed using X-ray powder diffraction (XRD), infrared (IR) spectra, thermal gravimetric analyses (TGA), inductively coupled plasma (ICP) and elemental analyses. - Graphical abstract: A new three-dimensional iron phosphite with intersecting 6-, 8-, 10-ring channels has been solvothermally synthesized by using diethylenetriamine (DETA) as the structure-directing agent.

  11. The reaction H + C4H2 - Absolute rate constant measurement and implication for atmospheric modeling of Titan

    NASA Astrophysics Data System (ADS)

    Nava, D. F.; Mitchell, M. B.; Stief, L. J.

    1986-04-01

    The absolute rate constant for the reaction H + C4H2 has been measured over the temperature (T) interval 210-423 K, using the technique of flash photolysis-resonance fluorescence. At each of the five temperatures employed, the results were independent of variations in C4H2 concentration, total pressure of Ar or N2, and flash intensity (i.e., the initial H concentration). The rate constant, k, was found to be equal to 1.39 x 10 to the -10th exp (-1184/T) cu cm/s, with an error of one standard deviation. The Arrhenius parameters at the high pressure limit determined here for the H + C4H2 reaction are consistent with those for the corresponding reactions of H with C2H2 and C3H4. Implications of the kinetic carbon chemistry results, particularly those at low temperature, are considered for models of the atmospheric carbon chemistry of Titan. The rate of this reaction, relative to that of the analogous, but slower, reaction of H + C2H2, appears to make H + C4H2 a very feasible reaction pathway for effective conversion of H atoms to molecular hydrogen in the stratosphere of Titan.

  12. Chloride-based SiC growth on a-axis 4H-SiC substrates

    NASA Astrophysics Data System (ADS)

    Booker, Ian D.; Farkas, Ildiko; Ivanov, Ivan G.; Hassan, Jawad ul; Janzén, Erik

    2016-01-01

    SiC has, during the last few years, become increasingly important as a power-device material for high voltage applications. The thick, low-doped voltage-supporting epitaxial layer is normally grown by CVD on 4° off-cut 4H-SiC substrates at a growth rate of 5 - 10 μm / h using silane (SiH4) and propane (C3H8) or ethylene (C2H4) as precursors. The concentrations of epitaxial defects and dislocations depend to a large extent on the underlying substrate but can also be influenced by the actual epitaxial growth process. Here we will present a study on the properties of the epitaxial layers grown by a Cl-based technique on an a-axis (90° off-cut from c-direction) 4H-SiC substrate.

  13. 4-H Club Goat Guide.

    ERIC Educational Resources Information Center

    Brown, R. Kipp

    This guide provides information for 4-H Club members who have decided on a club goat project. Topics include general information in the following areas: show rules; facilities and equipment (barns/sheds, fences, feeders, water containers, and equipment); selection (structural correctness, muscle, volume and capacity, style and balance, and growth…

  14. Recruiting 4-H Volunteer Leaders.

    ERIC Educational Resources Information Center

    National Four-H Club Foundation, Washington, DC.

    The guide is intended to assist 4-H Club extension workers in recruiting volunteer adult and youth leaders. It discusses: why volunteers serve (organizational identity, desire to serve, involvement of other family members, future opportunities and obligations, community status, self interest, and public opinion); how to recruit (person-to-person…

  15. Protonation of metal hydrides by strong acids. Formation of an equilibrium mixture of dihydride and dihydrogen complexes from protonation of Cp{sup *}Os(CO){sub 2}H. Structural characterization of [CpW(CO){sub 2}(PMe{sub 3})(H){sub 2}]{sup +}OTf{sup -}

    SciTech Connect

    Bullock, R.M.; Song, J.S.; Szalda, D.J.

    1996-05-14

    Cp{sup *}Os(CO){sub 2}H is protonated by triflic acid (HOTf) in CD{sub 2} Cl{sub 2} solution to give an equilibrium mixture (87:13) of the dihydride [Cp{sup *}Os(CO){sub 2}(H){sub 2}]{sup +}OTf{sup -} and the dihydrogen complex [Cp{sup *}Os(CO){sub 2}({eta}{sup 2}-H{sub 2})]{sup +}OTf{sup -}. The acidity of these protonated species is roughly comparable to HOTf, since only partial protonation was observed. In the absence of acid, the T{sub 1} of the hydride ligand of Cp{sup *}Os(CO){sub 2}H is 5.9 s at -80{degree}C. When all of the Cp{sup *}Os(CO){sub 2}H is protonated by excess HOTf,the T{sub l} (-80{degree}C) of the terminal hydride ligands of [Cp{sup *}Os(CO){sub 2}(H){sub 2}]{sup +}OTf{sup -} is 2.8 s, while the T{sub l} of the dihydrogen ligand of [Cp{sup *}Os(CO){sub 2}({eta}{sup 2}-H{sub 2})]{sup +} OTf{sup -} is 19 ms, (-80{degree}C). The observed T{sub l} values of the Os-H resonance of Cp{sup *}Os(CO){sub 2}H decreased significantly under conditions of partial protonation, indicating intermolecular proton transfer among [Cp{sup *}Os(CO){sub 2}({eta}{sup 2}H{sub 2})]{sup +}OTf{sup -}, [Cp{sup *}Os(CO){sub 2}(H){sub 2}]{sup +}OTf{sup -}, Cp{sup *}Os(CO){sub 2}H, and HOTf. IR spectra indicate that the two CO ligands of [Cp{sup *}Os(CO){sub 2}(H){sub 2}]{sup +} (and hence the hydrides as well) are trans to each other in the four-legged piano stool geometry. 62 refs., 6 figs., 8 tabs.

  16. Extended networks, porous sheets, and chiral frameworks. Thorium materials containing mixed geometry anions: Structures and properties of Th(SeO{sub 3})(SeO{sub 4}), Th(IO{sub 3}){sub 2}(SeO{sub 4})(H{sub 2}O){sub 3}.H{sub 2}O, and Th(CrO{sub 4})(IO{sub 3}){sub 2}

    SciTech Connect

    Sullens, Tyler A.; Almond, Philip M.; Byrd, Jessica A.; Beitz, James V.; Bray, Travis H.; Albrecht-Schmitt, Thomas E. . E-mail: albreth@auburn.edu

    2006-04-15

    Three novel Th(IV) compounds containing heavy oxoanions, Th(SeO{sub 3})(SeO{sub 4}) (1), Th(IO{sub 3}){sub 2}(SeO{sub 4})(H{sub 2}O){sub 3}.H{sub 2}O (2), and Th(CrO{sub 4})(IO{sub 3}){sub 2} (3), have been synthesized under mild hydrothermal conditions. Each of these three distinct structures contain trigonal pyramidal and tetrahedral oxoanions. Compound 1 adopts a three-dimensional structure formed from ThO{sub 9} tricapped trigonal prisms, trigonal pyramidal selenite, SeO{sub 3}{sup 2-}, anions containing Se(IV), and tetrahedral selenate, SeO{sub 4}{sup 2-}, anions containing Se(VI). The structure of 2 contains two-dimensional porous sheets and occluded water molecules. The Th centers are found as isolated ThO{sub 9} tricapped trigonal prisms and are bound by four trigonal pyramidal iodate anions, two tetrahedral selenate anions, and three coordinating water molecules. In the structure of 3, the Th(IV) cations are found as ThO{sub 9} tricapped trigonal prisms. Each Th center is bound by six IO{sub 3}{sup 1-} anions and three CrO{sub 4}{sup 2-} anions forming a chiral three-dimensional structure. Second-harmonic generation of 532nm light from 1064nm radiation by a polycrystalline sample of 3 was observed. Crystallographic data (193K, MoK{alpha}, {lambda}=0.71073): 1; monoclinic, P2{sub 1}/c; a=7.0351(5)A, b=9.5259(7)A, c=9.0266(7)A, {beta}=103.128(1), Z=4, R(F)=2.47% for 91 parameters with 1462 reflections with I>2{sigma}(I); 2, monoclinic, P2{sub 1}/n, a=7.4889(9)A, b=8.002(1)A, c=20.165(3)A, {beta}=100.142(2), Z=4, R(F)=4.71% for 158 parameters with 2934 reflections with I>2{sigma}(I); 3, orthorhombic, P2{sub 1}2{sub 1}2{sub 1}, a=7.3672(5)A, b=9.3617(6)A, c=11.9201(7)A, Z=4, R(F)=2.04% for 129 parameters with 2035 reflections with I>2{sigma}(I)

  17. Thermochemistry and dissociation dynamics of state-selected C/sub 4/H/sub 8/O/sub 2//sup +/ ions. 3. Ethyl acetate

    SciTech Connect

    Fraser-Monteiro, L.; Fraser-Monteiro, M.L.; Butler, J.J.; Baer, T.

    1982-01-01

    The photoionization efficiency curves and appearance energies of C/sub 4/H/sub 8/O/sub 2//sup +/, C/sub 3/H/sub 5/O/sub 2//sup +/, C/sub 4/H/sub 6/O/sup +/, C/sub 2/H/sub 5/O/sub 2//sup +/, C/sub 2/H/sub 5/O/sup +/, C/sub 2/H/sub 3/O/sup +/, and C/sub 2/H/sub 5//sup +/ from ethyl acetate have been obtained. Structures and heats of formation of some of the ions are proposed. The ethyl acetate ion was found to be metastable in the vicinity of the first dissociation onset producing C/sub 4/H/sub 6/O/sup +/ (m/e 70) and H/sub 2/O. The decay rates as a function of parent ion internal energy were measured betwen 10.4 and 10.7 eV. The comparison of the observed rates with those calculated by use of the RRKM/QET statistical theory indicates that the the ethyl acetate ion isomerizes to a more stable ion prior to dissociation. The isomerized structure is neither that of dioxane nor butanoic acid, but may be the enol tautomer of ethyl acetate.

  18. Optimizing Synthesis of Na2Ti2SiO7 - 2H2O (Na-CST) and Ion Exchange Pathways for Cs0.4H1.6Ti2SiO7 - H2O (Cs-CST) Determined from in situ Synchrotron X-ray Powder Diffraction

    SciTech Connect

    Celestian,A.; Medvedev, D.; Tripathi, A.; Parise, J.; Clearfield, A.

    2005-01-01

    Observation of wide angle diffraction data collected in situ during previous synthesis of Na-CST (Na{sub 2}Ti{sub 2}SiO{sub 7}-2H{sub 2}O) showed initial crystallization of a precursor phase (SNT) at 30 C followed by conversion to CST after 1 h at 220 C. In situ studies of Cs{sup +} ion exchange into the H{sup +} form of CST showed a site-by-site ion exchange pathway accompanied by a simultaneous structural transition from P4{sub 2}/mbc (cell parameters a = 11.0690(6) Angstroms, c = 11.8842(6) Angstroms) to P4{sub 2}/mcm (cell parameters a = 7.847(2) Angstroms, c = 11.9100(6) Angstroms). After approximately 18% Cs{sup +} exchange into site designated Cs2 in space group P4{sub 2}/mcm, a site designated Cs1 in space group P4{sub 2}/mcm began to fill at the center of the 8MR windows until a maximum of approximately 22% exchange was achieved for Cs1. Bond valence sums of site Cs1 to framework O{sup 2-} are 1.00 v.u., while bond valence sums of site Cs2 to framework O{sup 2-} are 0.712 v.u. suggesting Cs1 to have a more stable bonding environment.

  19. The composition of Saturn's atmosphere at northern temperate latitudes from Voyager IRIS spectra - NH3, PH3, C2H2, C2H6, CH3D, CH4, and the Saturnian D/H isotopic ratio

    NASA Technical Reports Server (NTRS)

    Courtin, R.; Gautier, D.; Marten, A.; Bezard, B.; Hanel, R.

    1984-01-01

    The vertical distributions and mixing ratios of minor constituents in the northern hemisphere of Saturn are investigated. Results are obtained for NH3, PH3, C2H2, C2H6, CH3D, and CH4; the D/H ratio is obtained from the CH4 and CH3D abundances. The NH3 mixing ratio in the upper atmosphere is found to be compatible with the saturated partial pressure. The inferred PH3/H2 ratio of 1.4 + or - 0.8 x 10 to the -6th is higher than the value derived from the solar P/H ratio. The stratospheric C2H2/H2 and C2H6/H2 ratios are, respectively, 2.1 + or - 1.4 x 10 to the -7th and 3.0 + or - 1.1 x 10 to the -6th; the latter decreases sharply below the 20-50 mbar level. The results for CH3D/H2 and CH4/H2 imply an enrichment of Saturn's upper atmosphere in carbon by a factor of at least three over the solar abundance. The interpretation of two NH3 lines in the five-micron window suggests a NH3/H2 ratio at the two bar level below the solar value.

  20. Polynuclear complexes with bridging pyrophosphate ligands: synthesis and characterisation of {[(bipy)Cu(H2O)(mu-P2O7)Na2(H2O)6] x 4H2O}, {[(bipy)Zn-(H2O)(mu-P2O7)Zn(bipy)]2 x 14H2O} and {[(bipy)(VO)2]2(mu-P2O7)] x 5H2O}.

    PubMed

    Doyle, Robert P; Nieuwenhuyzen, Mark; Kruger, Paul E

    2005-12-01

    The reaction in water of M(II) ions (M = Cu, 1; Zn, 2; VO, 3) with 2,2'-bipyridine (bipy) followed by Na4P2O7 leads to the formation of three new complexes which feature the pyrophosphate anion, P2O7(4-), as a bridging ligand. Single crystal X-ray diffraction revealed 1 to be {[(bipy)Cu(H2O)(micro-P2O7)Na2(H2O)6] x 4H2O}, and 2 as a tetranuclear Zn(II) complex, {[(bipy)Zn(H2O)(micro-P2O7)Zn(bipy)]2 x 14H2O}. The structure of 1 consists of a mononuclear [(bipy)Cu(H2O)(P2O7)]2- unit that links via a pyrophosphate bridge to two Na atoms. The hydrated six-coordinate Na atoms themselves join together through bridging water molecules to generate a 2D Na-water sheet. The structure of 2 consists of a tetranuclear Zn(II) cluster (dimer-of-dimers) with two pyrophosphate ligands bridging between four metal centres. Adjacent clusters interact through face-to-face pi-pi interactions via the bipy ligands to yield a 2D sheet. Adjacent sheets pack in register to create channels, which are filled by the water molecules of crystallisation. An intricate 2D H-bonded water network separates adjacent sheets and encapsulates the tetranuclear clusters. Aspects of the pyrophosphate coordination modes in 1 and 2 are of structural relevance to those found within the inorganic pyrophosphatases. Compound 3, {[(bipy)(VO)2]2(micro-P2O7)] x 5H2O}, was isolated as an insoluble lime-green powder. Its dinuclear structure was elucidated from elemental and thermal analysis, magnetic susceptibility measurement and IR spectroscopy. The latter displayed characteristic bridging pyrophosphate and signature V=O stretches, which were corroborated by contrast to the IR spectra of 1 and 2 and through comparison with those found in the structurally characterised dinuclear complex, {[(bipy)Cu(H2O)]2(micro-P2O7) x 7H2O}, 4. PMID:16471055

  1. Metal ion interactions with nucleobases in the tetradentate 1,4,7,10-tetraazacyclododecane (cyclen)-ligand system: Crystal structures of [Cu(cyclen)(adeninato)]·ClO 4·2H 2O, [{Cu(cyclen)} 2(hypoxanthinato)]·(ClO 4) 3, [Cu(cyclen)(theophyllinato)] 3·(ClO 4) 3·2H 2O, and [Cu(cyclen)(xanthinato)]·(0.7ClO 4)·(0.3ClO 4)·3H 2O·(0.5H 2O) 3

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Shahidur; Yuan, Hou Qun; Kikuchi, Takanori; Fujisawa, Ikuhide; Aoki, Katsuyuki

    2010-03-01

    Reaction of 1,4,7,10-tetraazacyclododecane (cyclen) and Cu(ClO 4) 2·6H 2O with nucleobases (adenine, hypoxanthine, xanthine, theophylline, cytosine, or uracil) under alkaline conditions gave four ternary cyclen-metal-nucleobase complexes, [Cu(cyclen)(adeninato)]·ClO 4·2H 2O ( 1), [{Cu(cyclen)} 2(hypoxanthinato)]·(ClO 4) 3 ( 2), [Cu(cyclen)(theophyllinato)] 3·(ClO 4) 3·2H 2O ( 3), and [Cu(cyclen)(xanthinato)]·(0.7ClO 4)·(0.3ClO 4)·3H 2O·(0.5H 2O) 3 ( 4), whose crystal structures were determined by X-ray diffraction. In the adenine complex 1, a cyclen-capped square-pyramidal Cu 2+ ion binds to an adeninato ligand through N(9) with the formation of an intramolecular interligand hydrogen bond between the secondary amino nitrogen of cyclen and N(3) of the base. In the hypoxanthine complex 2, two cyclen-capped Cu 2+ ions bind to a hypoxanthinato ligand, one through N(7) with the formation of an intramolecular N(cyclen)-H···O(6) hydrogen bond and the other through N(9) to form an intramolecular N(cyclen)-H···N(3) hydrogen bond. Similarly, in both the theophylline complex 3 and the xanthine complex 4, each cyclen-capped Cu 2+ ion binds to a theophyllinato or xanthinato ligand through N(7) with the formation of an intramolecular N(cyclen)-H···O(6) hydrogen bond. However, unlike in 2, steric constraints between amino group(s) of cyclen and the methyl group at N(3) of theophylline in 3 or the proton attached to N(9) of xanthine in 4 preclude the metal bonding to N(9) in 3 or N(3) in 4. The significance of intramolecular interligand interaction as a factor that affects metal-binding site(s) on nucleobases is emphasized.

  2. Synthesis, structure, and physical properties of [Sm(C{sub 6}NO{sub 2}H{sub 5}){sub 3}(H{sub 2}O){sub 2}]{sub 2n}.(H{sub 5}O{sub 2}){sub n}(ZnCl{sub 5}){sub n}(ZnCl{sub 4}){sub 2n}.(H{sub 2}O){sub 2n} with unprecedented ZnCl{sub 5}{sup 3-} species

    SciTech Connect

    Xie Yiming Chen Wentong; Wu Jihuai

    2008-08-15

    A novel bimetallic 4f-3d metal-isonicotinic acid inorganic-organic hybrid complex [Sm(C{sub 6}NO{sub 2}H{sub 5}){sub 3}(H{sub 2}O){sub 2}]{sub 2n}.(H{sub 5}O{sub 2}){sub n}(ZnCl{sub 5}){sub n}(ZnCl{sub 4}){sub 2n}.(H{sub 2}O){sub 2n} (1) has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 is characteristic of a one-dimensional polycationic chain-like structure and unprecedented ZnCl{sub 5}{sup 3-} species. Photoluminescent investigation reveals that the title complex displays interesting emissions in a wide region. Optical absorption spectra of 1 reveal the presence of an optical gap of 3.59 eV. - Graphical abstract: A novel bimetallic 4f-3d metal-isonicotinic acid inorganic-organic hybrid complex was synthesized. It is characteristic of a one-dimensional polycationic chain-like structure. Photoluminescent investigation reveals that the title complex displays interesting emissions in a wide region. Optical absorption spectra of 1 reveal the presence of a wide optical bandgap.

  3. Adult 4-H Volunteer Empowerment in 4-H Youth Development Settings

    ERIC Educational Resources Information Center

    Olsen, Pamela

    2009-01-01

    The primary purpose of this study was to determine which factors related to adult 4-H volunteer empowerment in 4-H youth development settings. This study examined the relationship of adult 4-H volunteers' perceived leadership styles of Oregon 4-H Youth Development Educators (YDE) to the adult 4-H volunteer sense of empowerment. In addition,…

  4. Strengthening 4-H by Analyzing Enrollment Data

    ERIC Educational Resources Information Center

    Hamilton, Stephen F.; Northern, Angela; Neff, Robert

    2014-01-01

    The study reported here used data from the ACCESS 4-H Enrollment System to gain insight into strengthening New York State's 4-H programming. Member enrollment lists from 2009 to 2012 were analyzed using Microsoft Excel to determine trends and dropout rates. The descriptive data indicate declining 4-H enrollment in recent years and peak…

  5. Engaging Library Partners in 4-H Programming

    ERIC Educational Resources Information Center

    Fields, Nia Imani; Rafferty, Elizabeth

    2012-01-01

    When most people think about 4-H, they remember county fairs, livestock programs, and agricultural education. While these programs are still prominent, 4-H has grown in order to meet the growing demands of today's youth. The organization has expanded services and programs to serve rural, suburban, and urban youth in every state in the U.S. 4-H is…

  6. Rate Constant and RRKM Product Study for the Reaction Between CH3 and C2H3 at T = 298K

    NASA Technical Reports Server (NTRS)

    Thorn, R. Peyton, Jr.; Payne, Walter A., Jr.; Chillier, Xavier D. F.; Stief, Louis J.; Nesbitt, Fred L.; Tardy, D. C.

    2000-01-01

    The total rate constant k1 has been determined at P = 1 Torr nominal pressure (He) and at T = 298 K for the vinyl-methyl cross-radical reaction CH3 + C2H3 yields products. The measurements were performed in a discharge flow system coupled with collision-free sampling to a mass spectrometer operated at low electron energies. Vinyl and methyl radicals were generated by the reactions of F with C2H4 and CH4, respectively. The kinetic studies were performed by monitoring the decay of C2H3 with methyl in excess, 6 < |CH3|(sub 0)/|C2H3|(sub 0) < 21. The overall rate coefficient was determined to be k1(298 K) = (1.02 +/- 0.53)x10(exp -10) cubic cm/molecule/s with the quoted uncertainty representing total errors. Numerical modeling was required to correct for secondary vinyl consumption by reactions such as C2H3 + H and C2H3 + C2H3. The present result for k1 at T = 298 K is compared to two previous studies at high pressure (100-300 Torr He) and to a very recent study at low pressure (0.9-3.7 Torr He). Comparison is also made with the rate constant for the similar reaction CH3 + C2H5 and with a value for k1 estimated by the geometric mean rule employing values for k(CH3 + CH3) and k(C2H3 + C2H3). Qualitative product studies at T = 298 K and 200 K indicated formation of C3H6, C2H2, and C2H5 as products of the combination-stabilization, disproportionation, and combination-decomposition channels, respectively, of the CH3 + C2H3 reaction. We also observed the secondary C4H8 product of the subsequent reaction of C3H5 with excess CH3; this observation provides convincing evidence for the combination-decomposition channel yielding C3H5 + H. RRKM calculations with helium as the deactivator support the present and very recent experimental observations that allylic C-H bond rupture is an important path in the combination reaction. The pressure and temperature dependencies of the branching fractions are also predicted.

  7. SEARCHING FOR INTERSTELLAR MOLECULE BUTATRIENYLIDENE IN REACTION C{sub 2} + C{sub 2}H{sub 4}

    SciTech Connect

    Lee, Shih-Huang; Huang, Wen-Jian; Lin, Yi-Cheng; Chin, Chih-Hao

    2012-11-01

    We investigated the reaction C{sub 2}(X {sup 1}{Sigma}{sup +} {sub g}/a {sup 3}{Pi} {sub u}) + C{sub 2}H{sub 4} at collision energy 5.0 kcal mol{sup -1} in a crossed molecular-beam apparatus using selective photoionization. Time-of-flight and photoionization spectra of products C{sub 4}H{sub 3} and C{sub 4}H{sub 2} were measured. From the best simulation of product time-of-flight spectra, a low-energy-biased translational-energy distribution and an isotropic angular distribution are derived for product channels C{sub 4}H{sub 3} + H and C{sub 4}H{sub 2} + H{sub 2} that have average translational-energy releases of 11 and 20 kcal mol{sup -1}, respectively. Product C{sub 4}H{sub 3} is identified as H{sub 2}CCCCH because its ionization threshold 8.0 {+-} 0.2 eV and maximal translational-energy release 42 kcal mol{sup -1} coincide with that of product channel H{sub 2}CCCCH + H. H{sub 2}CCCC (butatrienylidene) and HCCCCH (diacetylene) might have contributions to product C{sub 4}H{sub 2}; both isomers have ionization energies near the measured ionization threshold 10.0 {+-} 0.2 eV and the maximal translational-energy release 62 kcal mol{sup -1} is within the energetic limits of both isomeric product channels. Nonetheless, channel H{sub 2}CCCC + H{sub 2} is suggested to be more dominant than channel HCCCCH + H{sub 2} because the maximal translational-energy release is in good agreement with the available energy of the former channel and the former channel is 3.8 times the branching ratio of the later channel predicted by Rice-Ramsperger-Kassel-Marcus calculations. C{sub 4}H{sub 2} is identified for the first time in the barrierless reaction C{sub 2} + C{sub 2}H{sub 4} which has never been considered in any astronomical chemical networks. This work sheds new light on the formation of butatrienylidene/diacetylene in cold interstellar media where C{sub 2} and C{sub 2}H{sub 4} are abundant.

  8. Community Development: A 4-H Intern Report.

    ERIC Educational Resources Information Center

    Scheneman, C. Stephen

    State progress reports on the 4-H/Community Development program, a 1973 nationwide Federally sponsored program facilitating youth in community decision-making processes, indicate that the program appears to be evolving into a viable and integral part of the total 4-H program. Although the report describes unique program features of various States,…

  9. Holding on to 4-H Leaders.

    ERIC Educational Resources Information Center

    Hass, Glen

    1979-01-01

    Data from a survey of 4-H Club leaders in Saskatchewan, Canada, were used to determine the effect of attendance at leadership training events on leaders' decisions to re-enroll or discontinue. It was found that involvement in 4-H activities, supported by leadership training, increased leaders' satisfaction and likelihood of re-enrolling. (MF)

  10. Strengthening 4-H Program Communication through Technology

    ERIC Educational Resources Information Center

    Robideau, Kari; Santl, Karyn

    2011-01-01

    Advances in technology are transforming how youth and parents interact with programs. The Strengthening 4-H Communication through Technology project was implemented in eight county 4-H programs in Northwest Minnesota. This article outlines the intentional process used to effectively implement technology in program planning. The project includes:…

  11. 3H-Penciclovir (3H-PCV) Uptake Assay

    PubMed Central

    Sekar, Thillai V; Paulmurugan, Ramasamy

    2016-01-01

    Thymidine Kinase from human Herpes simplex virus type 1 (HSV1-TK) in combination with specific substrate prodrug nucleotide analogue ganciclovir (GCV) has been widely used as suicidal therapeutic gene for cancer gene therapy. HSV1, and its mutant (HSV1-sr39TK) with improved substrate specificity, were used as reporter genes for PET-imaging of various biological functions in small animals, by combining with radiolabeled substrates such as 18F-FHBG and 124I-FIAU. 3H-Penciclovir (PCV) uptake assay is a method of choice used to determine the expression level of HSV1-TK in mammalian cells and tissues. HSV1-TK phosphorylate PCV and result in the formation of penciclovir monophosphate, and its subsequent phopsphorylation by cellular TK lead to the formation of penciclovir triphosphate, which is trapped selectively in cells expressing HSV-TK. 3H-Penciclovir enables the detection of penciclovir uptake of mammalian cells and tissues by radioactive procedures such as scintillation counting. Here we describe the protocol to carry out 3H-Penciclovir uptakes in mammalian cells.

  12. Structure determination of an amorphous compound AlB4H11.

    SciTech Connect

    Chen, Xuenian; Zhang, Yongsheng; Wang, Yongli; Zhou, Wei; Knight, Douglas A; Yisgedu, Teshome; Huang, Zhenguo; Lingam, Hima; Billet, Beau; Udovic, Terrence J; Brown, Gilbert M; Shore, Sheldon; Wolverton, Christopher; Zhao, J.-C.

    2012-01-01

    The structure of the amorphous aluminoborane compound AlB4H11 was identified through a collaborative study closely coupling a first-principles density functional based approach with experimental measurements using IR, NMR, and neutron vibrational spectroscopy (NVS). The AlB4H11 structure was found to contain distinct [BH4] and [B3H7] units without any [AlH4] units. It forms a [B3H7] Al(BH4) polymer chain with the [BH4] units twisted relative to each other perpendicular to the chain direction and bonded to Al, and a chain backbone consists of [B3H7] and Al where the [B3H7] unit exhibits a triangular boron configuration. The computed lowest energy structure shows good agreement with results of IR, NVS and NMR spectra; this agreement demonstrates the extended applicability of the structure prediction approach to the prediction of even amorphous compounds.

  13. Relationships between 4-H Volunteer Leader Competencies and Skills Youth Learn in 4-H Programs

    ERIC Educational Resources Information Center

    Radhakrishna, Rama; Ewing, John C.

    2011-01-01

    This article examined the relationships between 4-H volunteer leader competencies and skills youth learn in 4-H. Using a descriptive-correlational research, the study reported found significant relationships between leadership competencies and skills youth learn in 4-H. Regression analysis revealed that two variables--skills and…

  14. Middle Childhood: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    Part of a series for 4-H members between 9 and 19 years of age, this age-graded guide to the development of 6-, 7-, and 8-year-olds aims to help 4-H members who are children and adolescents themselves: (1) understand the physical, mental, social, and emotional development of children in middle childhood; (2) learn to care for a child in middle…

  15. Multi-state 4-H energy program

    SciTech Connect

    Bakker, U.B.; Garthe, J.W.

    1983-06-01

    Through Agricultural Engineering 4-H Energy Programs, youth can be educated to gain knowledge, increase hands on skills, and incorporate energy-saving techniques into their lifestyle. In a pilot multi-state energy program tested by 13 states, youth increased their energy awareness.

  16. 4-H Science Inquiry Video Series

    ERIC Educational Resources Information Center

    Green, Jeremy W.; Black, Lynette; Willis, Patrick

    2013-01-01

    Studies support science inquiry as a positive method and approach for 4-H professionals and volunteers to use for teaching science-based practices to youth. The development of a science inquiry video series has yielded positive results as it relates to youth development education and science. The video series highlights how to conduct science-rich…

  17. The Preschooler: 4-H Child Development Project.

    ERIC Educational Resources Information Center

    Francis, Connie M.

    Intended for 4-H participants who plan and implement activities in the area of child development, this booklet provides a study guide to help young learners: (1) gain understanding of a preschool child's physical, mental, social, and emotional growth; (2) learn to care for a preschooler and promote preschoolers' feelings of security and safety;…

  18. Separates. 4-H Textile Science Advanced Project.

    ERIC Educational Resources Information Center

    Scholl, Jan F.

    This booklet, which was developed for use by 4-H club members in Pennsylvania, contains the information required to sew a two-piece nontailored outfit and/or a one-or two-piece dress. The following are among the topics covered: the difference between a fiber and a fabric; properties of different fibers and fabrics; common jacket, neckline, sleeve,…

  19. Microautoradiographic localisation of [3H]sucrose and [3H]mannitol in Robinia pseudoacacia pulvinar tissues during phytochrome-mediated nyctinastic closure.

    PubMed

    Moysset, L; Llambrich, E; López-Iglesias, C; Simón, E

    2006-11-01

    We have analysed the incorporation of [(3)H]sucrose and [(3)H]mannitol in pulvinar motor cells of Robinia pseudoacacia L. during phytochrome-mediated nyctinastic closure. Pairs of leaflets, excised 2 h after the beginning of the photoperiod, were fed with 50 mM [(3)H]sucrose or [(3)H]mannitol, irradiated with red (15 min) or far-red (5 min) light and placed in the dark for 2-3 h. Label uptake was measured in whole pulvini by liquid scintillation counting. The distribution of labelling in pulvinar sections was assessed by both light and electron microautoradiography. [(3)H]Sucrose uptake was twice that of [(3)H]mannitol incorporation in both red- and far-red-irradiated pulvini. In the autoradiographs, [(3)H]sucrose and [(3)H]mannitol labelling was localised in the area from the vascular bundle to the epidermis, mainly in vacuoles, cytoplasm, and cell walls. Extensor and flexor protoplasts displayed a different distribution of [(3)H]sucrose after red and far-red irradiation. Far-red light drastically reduced the [(3)H]sucrose incorporation in extensor protoplasts and caused a slight increase in internal flexor protoplasts. After red light treatment, no differences in [(3)H]sucrose labelling were found between extensor and flexor protoplasts. Our results indicate a phytochrome control of sucrose distribution in cortical motor cells and seem to rule out the possibility of sucrose acting as an osmoticum. PMID:17102931

  20. National 4-H Common Measures: Initial Evaluation from California 4-H

    ERIC Educational Resources Information Center

    Lewis, Kendra M.; Horrillo, Shannon J.; Widaman, Keith; Worker, Steven M.; Trzesniewski, Kali

    2015-01-01

    Evaluation is a key component to learning about the effectiveness of a program. This article provides descriptive statistics of the newly developed National 4-H Common Measures (science, healthy living, citizenship, and youth development) based on data from 721 California 4-H youth. The measures were evaluated for their reliability and validity of…

  1. Effectiveness of the 4-H Program as Perceived by Parents of 4-H Participants

    ERIC Educational Resources Information Center

    Radhakrishna, Rama; Foley, Caitlin; Ingram, Patreese; Ewing, John C.

    2013-01-01

    The study reported here examined the effectiveness of 4-H program as perceived by parents of program participants. Descriptive-correlational design was employed, with data collected using a mail survey. Parents perceived 4-H as an effective organization in teaching life skills to youth. Significant relationships were found between parents'…

  2. VIBRATIONALLY EXCITED C{sub 4}H

    SciTech Connect

    Cooksy, Andrew L.; Gottlieb, C. A.; Thaddeus, P.; Patel, Nimesh A.; Young, Ken H.; McCarthy, M. C.; Killian, T. C.

    2015-02-01

    Rotational spectra in four new excited vibrational levels of the linear carbon chain radical C{sub 4}H were observed in the millimeter band between 69 and 364 GHz in a low pressure glow discharge, and two of these were observed in a supersonic molecular beam between 19 and 38 GHz. All have rotational constants within 0.4% of the X{sup 2}Σ{sup +} ground vibrational state of C{sub 4}H and were assigned to new bending vibrational levels, two each with {sup 2}Σ and {sup 2}Π vibrational symmetry. The new levels are tentatively assigned to the 1ν{sub 6} and 1ν{sub 5} bending vibrational modes (both with {sup 2}Π symmetry), and the 1ν{sub 6}+1ν{sub 7} and 1ν{sub 5}+1ν{sub 6} combination levels ({sup 2}Σ symmetry) on the basis of the derived spectroscopic constants, relative intensities in our discharge source, and published laser spectroscopic and quantum calculations. Prior spectroscopic constants in the 1ν{sub 7} and 2ν{sub 7} levels were refined. Also presented are interferometric maps of the ground state and the 1ν{sub 7} level obtained with the Submillimeter Array (SMA) near 257 GHz which show that C{sub 4}H is present near the central star in IRC+10216. We found no evidence with the SMA for the new vibrationally excited levels of C{sub 4}H at a peak flux density averaged over a 3{sup ′′} synthesized beam of ⩾0.15 Jy/beam in the 294–296 and 304–306 GHz range, but it is anticipated that rotational lines in the new levels might be observed in IRC+10216 when ALMA attains its full design capability.

  3. Learnings and Recommendations to Advance 4-H Science Readiness

    ERIC Educational Resources Information Center

    Schmitt-McQuitty, Lynn; Carlos, Ramona; Smith, Martin H.

    2014-01-01

    The case study investigation reported here assessed California 4-H professionals' understanding of the essential components of effective 4-H Science programming as established by the National 4-H Science Mission Mandate. Using the 4-H Science Checklist as the basis for defining 4-H Science Readiness, academic and program staff were surveyed…

  4. Direct measurements of rate constants for the reactions of CH3 radicals with C2H6, C2H4, and C2H2 at high temperatures.

    PubMed

    Peukert, S L; Labbe, N J; Sivaramakrishnan, R; Michael, J V

    2013-10-10

    The shock tube technique has been used to study the reactions CH3 + C2H6 → C2H4 + CH4 + H (1), CH3 + C2H4 → Products + H (2), and CH3 + C2H2 → Products + H (3). Biacetyl, (CH3CO)2, was used as a clean high temperature thermal source for CH3-radicals for all the three reactions studied in this work. For reaction 1, the experiments span a T-range of 1153 K ≤ T ≤ 1297 K, at P ~ 0.4 bar. The experiments on reaction 2 cover a T-range of 1176 K ≤ T ≤ 1366 K, at P ~ 1.0 bar, and those on reaction 3 a T-range of 1127 K ≤ T ≤ 1346 K, at P ~ 1.0 bar. Reflected shock tube experiments performed on reactions 1-3, monitored the formation of H-atoms with H-atom Atomic Resonance Absorption Spectrometric (ARAS). Fits to the H-atom temporal profiles using an assembled kinetics model were used to make determinations for k1, k2, and k3. In the case of C2H6, the measurements of [H]-atoms were used to derive direct high-temperature rate constants, k1, that can be represented by the Arrhenius equation k1(T) = 5.41 × 10(-12) exp(-6043 K/T) cm(3) molecules(-1) s(-1) (1153 K ≤ T ≤ 1297 K) for the only bimolecular process that occurs, H-atom abstraction. TST calculations based on ab initio properties calculated at the CCSD(T)/CBS//M06-2X/cc-pVTZ level of theory show excellent agreement, within ±20%, of the measured rate constants. For the reaction of CH3 with C2H4, the present rate constant results, k2', refer to the sum of rate constants, k(2b) + k(2c), from two competing processes, addition-elimination, and the direct abstraction CH3 + C2H4 → C3H6 + H (2b) and CH3 + C2H4 → C2H2 + H + CH4 (2c). Experimental rate constants for k2' can be represented by the Arrhenius equation k2'(T) = 2.18 × 10(-10) exp(-11830 K/T) cm(3) molecules(-1) s(-1) (1176 K ≤ T ≤ 1366 K). The present results are in excellent agreement with recent theoretical predictions. The present study provides the only direct measurement for the high-temperature rate constants for these channels

  5. Synthesis, optical, and thermal properties of glassy trityl group containing luminescent derivatives of 2-tert-butyl-6-methyl-4H-pyran-4-one

    NASA Astrophysics Data System (ADS)

    Zarins, Elmars; Siltane, Karina; Misina, Elina; Kokars, Valdis; Lazdovica, Kristine; Vembris, Aivars; Kampars, Valdis; Muzikante, Inta; Rutkis, Martins

    2012-06-01

    In this work we present simple preparation of original trityl group containing glassy luminescent 6-styryl substituted derivatives of 2-(2-tert-butyl-4H-pyran-4-ylidene)malononitrile (DWK-1TB), 2-(2-tert-butyl-4H-pyran-4-ylidene)-2- ethyl-2-cyanoacetate (KWK-1TB), 2-(2-tert-butyl-4H-pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK-1TB) and 5-(2-tert-butyl-4H-pyran-4-ylidene)pyrimidine-2,4,6(1H,3H,5H)-trione (JWK-1TB). Their optical properties have been investigated. The absorption maxima of synthesized glasses is in region from 425 nm to 515 nm and emission maxima is from 470 nm to 625 nm in solution of dichloromethane. But absorption maxima of their solid films is from 425 nm to 500 nm and emission maxima is in range from 570 nm to 710 nm. Incorporation of bulky trityloxy ethyl groups combining with existing tert-butyl groups results in thin solid films formation of synthesized glasses from volatile organic solvents (chloroform, dichloromethane) without them being doped in any polymer. This makes them perspective for potential applications in organic light-emitting diodes and organic lasers by simple luminescent layer composition with cheap wet-casting approaches. All glasses show good thermal stability with thermal decomposition temperatures from 264° to 318°C and glass transition values up to 158°C for DWK-1TB. These thermal properties of synthesized glasses could make them also useful for potential applications in other optical materials such as materials for nonlinear optics.

  6. Synthesis and crystal and molecular structure of a tetranuclear cluster based on the rhenium(III)-bisorganohydrazino core: [Re(HNNC(4)H(3)N(2))(NNC(4)H(3)N(2))(OCH(3))(2)](4).

    PubMed

    Femia, Frank J; Chen, Xiaoyuan; Maresca, Kevin P; Babich, John W; Zubieta, Jon

    2000-09-01

    Reaction of NH(4)ReO(4) with excess 2-hydrazinopyrimidine in methanol yields [Re(eta(1)-NNC(4)H(3)N(2)H)(eta(2)-HNNC(4)H(3)N(2))Cl(3)] (1). Attempts to recrystallize 1 by slow diffusion of methanol into DMF after 8 months produced black crystals of [Re(HNNC(4)H(3)N(2))(NNC(4)H(3)N(2))(OCH(3))(2)](4) (2). The structure of 2 consists of isolated tetranuclear clusters, constructed from {Re(eta(2)-HNNC(4)H(3)N(2))(eta(1)-NNC(4)H(3)N(2))(OCH(3))(2)} units linked through the beta-nitrogen of the chelating organodiazene ligand of adjacent units into a box-like aggregate. PMID:20613968

  7. Thermodynamic properties and crystal structure refinement of ferricopiapite, coquimbite, rhomboclase, and Fe2(SO4)3(H2O)5

    USGS Publications Warehouse

    Majzlan, J.; Navrotsky, A.; McCleskey, R.B.; Alpers, C.N.

    2006-01-01

    Enthalpies of formation of ferricopiapite [nominally Fe4.67(SO4)6(OH)2 (H2O)20]. coquimbite [Fe2(SO4)3(H2O)9], rhomboclase [(H3O)Fe(SO4)2 (H2O)3], and Fe2(SO4)3(H2O)5 were measured by acid (5 N HCl) solution calorimetry. The samples were characterized by wet chemical analyses and synchrotron powder X-ray diffraction (XRD). The refinement of XRD patterns gave lattice parameters, atomic positions, thermal factors, and occupancies of the sites. The calculated formulae differ slightly from the nominal compositions: Fe4.78(SO4)6 (OH)2.34(H2O)20.71 (ferricopiapite), (Fe1.47Al0.53)(SO4)3 (H2O)9.65 (coquimbite), (H3O)1.34Fe(SO4)2.17 (H2O)3.06 (rhomboclase), and Fe2(SO4)3 (H2O)5.03. All thermodynamic data are given per mole of these formulae. The measured standard enthalpies (in kJ/mol) of formation from the elements (crystalline Fe, Al, S, and ideal gases O2 and H2) at T = 298.15 K are -4115.8??4.1 [Fe2(SO4)3 (H2O)5.03], -12045.1??9.2 (ferricopiapite), -5738.4??3.3 (coquimbite), and -3201.1??2.6 (rhomboclase). Standard entropy (S??) was estimated as a sum of entropies of oxide, hydroxide, and sulfate components. The estimated S?? (in J/mol.K) values for the iron sulfates are 488.2 [Fe2(SO4)3 (H2O)5.03], 1449.2 (ferricopiapite), 638.3 (coquimbite), and 380.1 (rhomboclase). The calculated Gibbs free energies of formation (in kJ/mol) are -3499.7??4.2 [Fe2(SO4)3 (H2O)5.03], -10089.8??9.3 (ferricopiapite), -4845.6??3.3 (coquimbite), and -2688.0??2.7 (rhomboclase). These results combined with other available thermodynamic data allow construction of mineral stability diagrams in the FeIII2(SO4)3-FeII SO4-H2O system. One such diagram is provided, indicating that the order of stability of ferric sulfate minerals with decreasing pH in the range of 1.5 to -0.5 is: hydronium jarosite, ferricopiapite, and rhomboclase. ?? 2006 E. Schweizerbart'sche Verlagsbuchhandlung.

  8. Minnesota 4-H Science of Agriculture Challenge: Infusing Agricultural Science and Engineering Concepts into 4-H Youth Development

    ERIC Educational Resources Information Center

    Rice, Joshua E.; Rugg, Bradley; Davis, Sharon

    2016-01-01

    Youth involved in 4-H projects have been engaged in science-related endeavors for years. Since 2006, 4-H has invested considerable resources in the advancement of science learning. The new Minnesota 4-H Science of Agriculture Challenge program challenges 4-H youth to work together to identify agriculture-related issues in their communities and to…

  9. Diversity Inclusion in 4-H Youth Programs: Examining the Perceptions among West Virginia 4-H Youth Professionals

    ERIC Educational Resources Information Center

    LaVergne, Douglas D.

    2013-01-01

    The study reported here sought to examine the perceptions of 4-H youth professionals towards diversity inclusion in 4-H youth programs. A majority of professionals positively reported that there are benefits for youth of color and youth with disabilities in 4-H youth programs. Respondents indicated that the lack of information about 4-H youth…

  10. Visual Display Study: National 4-H Center. A 4-H Intern Report.

    ERIC Educational Resources Information Center

    Farwell, Sanford W.

    An internship report cites ways in which the National 4-H Center could be more effective in a visual sense. The author suggests collecting the memorabilia already at the Center to form an historical museum and coordinating the historical items with present items. Impact areas, those with a lot of traffic, are discussed individually in terms of…

  11. The Big E (Energy). 4-H Energy Project. 4-H Member's E-Book, Unit 1.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 1 (ages 9-11) of the Nebraska 4-H Energy Project. In this project, members are required to: (1) use energy wisely by closing doors and turning off lights; (2) inspecting homes for energy use at least once; (3) judging the best use of lighting in a home; (4) sharing ideas about energy use in a…

  12. CPR: Purposeful Action. Putting New Life into 4-H.

    ERIC Educational Resources Information Center

    Jones, Deborah A.; Smith, William C.

    1988-01-01

    In Ohio, 4-H professionals found that it is necessary to conduct market research to have an effective program. Cardiopulmonary resuscitation (CPR) training has been successful in strengthening the 4-H position in the marketplace. (JOW)

  13. Reaction Mechanism and Product Branching Ratios of the CH + C3H6 Reaction: A Theoretical Study.

    PubMed

    Ribeiro, Joao Marcelo; Mebel, Alexander M

    2016-03-24

    The mechanism of CH(X(2)Π) reaction with propene has been studied with ab initio CCSD(T)-F12/CBS//B3LYP/6-311G(d,p) calculations of the C4H7 potential energy surface and RRKM/master equation calculations of unimolecular rate constants for the various isomerization and dissociation steps available to the C4H7 radicals. Product branching ratios were calculated and were found to strongly depend on the initial chemically activated C4H7 complex formed in a barrierless entrance channel. If the reaction is initiated via either CH addition to the double bond in propene or CH insertions into the terminal sp(2) C-H or single C-C bonds, then 1,3-butadiene + H are predicted to be the dominant products, ethene + C2H3 radical are minor but non-negligible products, and a small amount of 1,2-butadiene + H is also produced. The reaction then proceeds through a key CH3CHCH(•)CH2 intermediate, which loses an H atom to form either 1,3- or 1,2-butadiene or isomerizes to (•)CH2CH2CHCH2 and then dissociates to ethene + C2H3 radical. If CH inserts into a C-H bond in the CH3 group the (•)CH2CH2CHCH2 complex is formed directly and then the major reaction products are predicted to be ethene + C2H3 radical and 1,3-butadiene + H. Finally, if CH inserts into the middle sp(2) C-H bond, a branched CH3C((•)CH2)CH2 complex is produced, which predominantly decomposes to allene + CH3 radical. A comparison of the calculated reaction mechanism with available experimental data indicates that the CH addition entrance channel is favorable, in which case the computed branching ratios are in agreement with the experimental result of Loison and Bergeat, who measured the H elimination branching ratio of 78 ± 10%. However, the computed branching ratios quantitatively disagree with the experimental data by Trevitt et al., who observed a nearly 100% yield of the C4H6 + H products and also larger yields of 1,2-butadiene and 1-butyne than the calculations predict. The deviation of the theoretical results

  14. Hamsters?! What Does 4-H Stand for, Anyway?

    ERIC Educational Resources Information Center

    Grundeen, Brenda

    This paper briefly traces the history of 4-H youth development programs, explains what youth development is, and shows how the experiential learning model is used in 4-H. Begun over 75 years ago as a means of extending the learning of the land-grant university to rural youth, 4-H is part of the Cooperative Extension Service. The curriculum…

  15. Using Digital Classrooms to Conduct 4-H Club Meetings

    ERIC Educational Resources Information Center

    West, Patricia; Fuhrman, Nicholas E.; Morgan, A. Christian; Duncan, Dennis W.

    2012-01-01

    Using computer technology and digital classrooms to conduct 4-H Club meetings is an efficient way to continue delivering quality 4-H programming during times of limited resources and staff. Nineteen Junior and Senior 4-H'ers participated in seven digital classroom workshops using the Wimba Classroom application. These digital classroom…

  16. Factors Affecting Teen Involvement in Pennsylvania 4-H Programming

    ERIC Educational Resources Information Center

    Gill, Bart E.; Ewing, John C.; Bruce, Jacklyn A.

    2010-01-01

    The study reported here determined the factors that affect teen involvement in 4-H programming. The design of the study was descriptive and correlational in nature. Using a purposive sampling procedure, a survey questionnaire was distributed to all (N=214) 4-H members attending the 4-H State Leadership Conference. The major findings of the study…

  17. The 4-H Club Meeting: An Essential Youth Development Strategy

    ERIC Educational Resources Information Center

    Cassels, Alicia; Post, Liz; Nestor, Patrick I.

    2015-01-01

    The club meeting has served as a key delivery method for 4-H programming across the United States throughout its history. A survey of WV 4-H community club members reinforces the body of evidence that the 4-H club meeting is an effective vehicle for delivering positive youth learning opportunities within the umbrella of the Essential Elements of…

  18. Understanding the C3H2 cyclic-to-linear ratio in L1544

    NASA Astrophysics Data System (ADS)

    Sipilä, O.; Spezzano, S.; Caselli, P.

    2016-06-01

    Aims: We aim to understand the high cyclic-to-linear C3H2 ratio (32 ± 4) that has been observed toward L1544. Methods: We combined a gas-grain chemical model with a physical model for L1544 to simulate the column densities of cyclic and linear C3H2 observed toward L1544. The most important reactions for the formation and destruction of both forms of C3H2 were identified, and their relative rate coefficients were varied to find the best match to the observations. Results: We find that the ratio of the rate coefficients of C3H3+ + e- ➝ C3H2 + H for cyclic and linear C3H2 must be ~ 20 to reproduce the observations, depending on the branching ratios assumed for the C3H3+ + e- ➝ C3H + H2 reaction. In current astrochemical networks it is assumed that cyclic and linear C3H2 are formed in a 1:1 ratio in the aforementioned reactions. Laboratory studies and/or theoretical calculations are needed to confirm the results of our chemical modeling, which is based on observational constraints.

  19. Flame synthesis of multi-walled carbon nanotubes using CH{sub 4}-H{sub 2} fuel blends

    SciTech Connect

    Manciu, F.S.; Camacho, J.; Choudhuri, A.R.

    2008-07-01

    Flame synthesis of carbon nanotubes (CNTs) has the potential to become a cost effective, energy efficient and scalable method for large-volume commercial synthesis. The in-flame concentration of key particulate inception intermediates, i.e., CH{sub 3}, C{sub 2}H{sub 2}, C{sub 3}H{sub 3}, and C{sub 5}H{sub 5} can be tailored using hydrogen fuel blends to optimize and enhance the yield of flame synthesis processes. Additionally, synthesis of CNTs using hydrogen fuel blends (coal or biomass derived gases) creates new opportunities for efficient coal utilization and by-product synergism of coal-fired power plants. This article reports an investigation on the synthesis of CNTs using H{sub 2} doped CH{sub 4} flames. For a baseline study, nanostructures formed in diffusion flames of 100% CH{sub 4} at different fuel flow rates have been analyzed. Initially the yield of nanomaterials increases with the increase in H{sub 2} doping in the fuel mixture. However, at higher H{sub 2} concentration (10%) and flow velocity (Jet Exit Reynolds number > 200), formation of nanostructures diminishes and H{sub 2}-CH{sub 4} flames produce amorphous carbon and soot particles. The maximum yield of nanostructures occurs at 95-5% CH{sub 4}-H{sub 2} fuel compositions and 8.37E-07m{sup 3}/s (corresponding Jet Exit Reynolds number=200). Raman analyses of the pristine samples show the existence of distinctive multi-walled carbon nanotube (MWNT) D and G bands at 1321cm{sup -1} and 1595cm{sup -1}, respectively. Infrared absorption measurements of vibrational line characteristics of CNTs also reveal the presence of C-H bonds.

  20. Reevaluation of the reported observation of the {sub {lambda}}{sub {lambda}}{sup 4}H hypernucleus

    SciTech Connect

    Randeniya, S. D.; Hungerford, E. V.

    2007-12-15

    The results of experiment E906, undertaken at the Alternating Gradient Synchrotron of the Brookhaven National Laboratory (BNL-AGS), were reanalyzed to clarify the signature of the decays of the double- and single-{lambda} hypernuclei that could have been produced in this experiment. This reanalysis indicates that instead of the reported decay of {sub {lambda}}{sub {lambda}}{sup 4}H through a proposed resonance in {sub {lambda}}{sup 4}He, it is more probable that the decay of the {sub {lambda}}{sub {lambda}}{sup 7}He hypernucleus was observed. This decay was accompanied by a background of coincident decays of pairs of the single hypernuclear fragments {sub {lambda}}{sup 3}H with {sub {lambda}}{sup 4}H, {sub {lambda}}{sup 3}H with {sub {lambda}}{sup 3}H, and {sub {lambda}}{sup 4}H with {sub {lambda}}{sup 4}H. An attempt was also made to determine if any other double or coincident single hypernuclear species could be observed in the data.

  1. K4[Pt2(H2P2O5)4Cl]•3H2O

    NASA Astrophysics Data System (ADS)

    Villars, P.; Cenzual, K.; Gladyshevskii, R.; Shcherban, O.; Dubenskyy, V.; Kuprysyuk, V.; Savysyuk, I.; Zaremba, R.

    This document is part of Subvolume A11 'Structure Types. Part 11: Space Groups (135) P42/mbc - (123) P4/mmm' of Volume 43 'Crystal Structures of Inorganic Compounds' of Landolt-Börnstein - Group III 'Condensed Matter'.

  2. K4[Pt2(H2P2O5)4Br]•3H2O

    NASA Astrophysics Data System (ADS)

    Villars, P.; Cenzual, K.; Gladyshevskii, R.; Shcherban, O.; Dubenskyy, V.; Kuprysyuk, V.; Savysyuk, I.; Zaremba, R.

    This document is part of Subvolume A11 'Structure Types. Part 11: Space Groups (135) P42/mbc - (123) P4/mmm' of Volume 43 'Crystal Structures of Inorganic Compounds' of Landolt-Börnstein - Group III 'Condensed Matter'.

  3. Redetermination of [Gd(NO3)3(H2O)4]·2H2O

    PubMed Central

    Taha, Ziyad A.; Ajlouni, Abdulaziz; Hijazi, Ahmed K.; Kühn, Fritz E.; Herdtweck, Eberhardt

    2012-01-01

    The crystal structure of the title compound, tetra­aqua­tris­(nitrato-κ2 O,O′)gadolinium(III) dihydrate, was redetermined from single-crystal X-ray data. In comparison with the first determination [Ma et al. (1991 ▶). Wuji Huaxue Xuebao, 7, 351–353], all H atoms could be located, accompanied with higher accuracy and precision. The GdIII atom shows a ten-coordination with three nitrate ligands behaving in a bidentate manner and the other positions being occupied by four water mol­ecules, forming a distorted bicapped square anti­prism. Two nitrate ions coordinate to the metal atom with similar bond lengths while the third shows a more asymmetric bonding behaviour. An intricate network of O—H⋯O hydrogen bonds, including the lattice water mol­ecules, stabilizes the crystal packing. PMID:22807698

  4. Frequency comb assisted measurement of fundamental transitions of cold H3+, H2D+ and D2H+

    NASA Astrophysics Data System (ADS)

    Jusko, Pavol; Konietzko, Christoph; Schlemmer, Stephan; Asvany, Oskar

    2016-01-01

    H3+ and two of its deuterated variants have been trapped and cooled in a 4 K trap machine, and their fundamental vibrational transitions probed with the laser induced reactions method. With the help of a frequency comb system the line centers are determined with high accuracy and precision, typically well below 1 MHz. For the deuterated variants, ground state combination differences allow for comparison with existing rotational THz data, and the accurate prediction thereof.

  5. The Photon Polarization Parameter of 2H(n, γ)3H reaction with Inclusion of the Electric Quadrupole Contribution

    NASA Astrophysics Data System (ADS)

    Sadeghi, H.; Mosavi-Khansari, M.

    2014-09-01

    We use effective field theory (EFT) for the calculation of neutron—deuteron radiative capture at very low energies. We present here the use of EFT to calculate a low-energy photo-nuclear observable in three-body systems, the photon polarization parameter and fore—aft asymmetry at thermal neutron energies up to next-to-next to leading order (N2LO), with inclusion of the electric quadrupole contribution. The photon polarization parameter in total is found to be Rc = -0.421 ± 0.003 and is in good agreement with the other modern theoretical calculations based on modern nucleon—nucleon potentials. In comparison with our previous work, a satisfactory agreement with the available experimental data is found by inclusion of the electric quadrupole contribution.

  6. Redetermination of [Pr(NO3)3(H2O)4]·2H2O

    PubMed Central

    Decadt, Roel; Van Der Voort, Pascal; Van Driessche, Isabel; Van Deun, Rik; Van Hecke, Kristof

    2012-01-01

    The structure of the title compound, tetra­aqua­tris­(nitrato-κ2 O,O′)praseodymium(III) dihydrate, was redetermined. The structure models derived from the previous determinations [Rumanova et al. (1964 ▶). Kristallografiya, 9, 642–654; Fuller & Jacobson (1976 ▶). Cryst. Struct. Commun. 5, 349–352] were confirmed, but now with all H atoms unambiguously located, revealing a complex O—H⋯O hydrogen-bonding network, extending throughout the whole structure. In the title compound, the coordination environment of the PrIII atom can best be described as a distorted bicapped square anti­prism defined by three bidentate nitrate anions and four water mol­ecules. Additionally, two lattice water mol­ecules are observed in the crystal packing. The title compound is isotypic with several other lanthanide-containing nitrate analogues. PMID:22807700

  7. Why 4-H Members Leave: A Study of Discontinuance through Both Current 4-H Members and Former Members

    ERIC Educational Resources Information Center

    Chilek, Kevin Dwayne

    2012-01-01

    4-H members quit. It is part of every 4-H program, and according to the research, it is even part of growing up. If only we knew why they quit, we could possibly do something about it. To date, the reasons youth join 4-H have been more thoroughly researched than the reasons they quit. This study explores why youth choose to discontinue membership…

  8. Sewing Skills Progress Chart. 4-H Textile Science.

    ERIC Educational Resources Information Center

    Scholl, Jan F.

    This document, which was developed for use by Pennsylvania 4-H Club leaders and members, is a chart that can be used to help club members determine and document those sewing skills they already have and those they need to learn as they complete one or more 4-H Club sewing projects. The document begins with a note to club leaders and parents that…

  9. Council of Presidents: A Multifaceted Idea for 4-H

    ERIC Educational Resources Information Center

    Torretta, Alayne

    2015-01-01

    Communication between 4-H professionals and the youth they work with is an important part of a successful 4-H program. By creating a Council of Presidents comprised of officers of all the clubs in your county, you can increase communication while assuring your program addresses all four essential elements. The Council is also as a vehicle for…

  10. 4-H Participation and Science Interest in Youth

    ERIC Educational Resources Information Center

    Heck, Katherine; Carlos, Ramona M.; Barnett, Cynthia; Smith, Martin H.

    2012-01-01

    The study reported here investigated the impacts of participation in 4-H on young people's interest and participation in science. Survey data were collected from relatively large and ethnically diverse samples of elementary and high school-aged students in California. Results indicated that although elementary-grade 4-H members are not more…

  11. Embracing Scientific and Engineering Practices in 4-H

    ERIC Educational Resources Information Center

    Worker, Steven M.

    2013-01-01

    The 4-H Science Initiative has renewed efforts to strengthen 4-H programmatic and evaluation efforts in science and engineering education. A fundamental component of this initiative is to provide opportunities to youth to aid in their development of science process skills; however, emerging research stresses the importance of engaging youth in…

  12. Camping with a Purpose...A 4-H Handbook.

    ERIC Educational Resources Information Center

    Heller, John H.; And Others

    The 4-H handbook focuses on factors to consider and things to be done when developing a camping program. Since the emphasis, structure, and administration of 4-H camping varies, the booklet is flexible enough to be adapted to different state, district, and county situations. Major topics are camping's importance to extension education,…

  13. Socialization of Youth: Role of the 4-H Professional.

    ERIC Educational Resources Information Center

    Freebern, John Robert

    Many professional 4-H staff members lack a sufficient background in the social sciences, fail to understand the complexity of the socialization task, and are not aware of the changes made by other socialization agents in the community. This paper is designed to help the professional 4-H adult worker improve his role as a socialization agent.…

  14. Stabilization of 4H hexagonal phase in gold nanoribbons

    PubMed Central

    Fan, Zhanxi; Bosman, Michel; Huang, Xiao; Huang, Ding; Yu, Yi; Ong, Khuong P.; Akimov, Yuriy A.; Wu, Lin; Li, Bing; Wu, Jumiati; Huang, Ying; Liu, Qing; Eng Png, Ching; Lip Gan, Chee; Yang, Peidong; Zhang, Hua

    2015-01-01

    Gold, silver, platinum and palladium typically crystallize with the face-centred cubic structure. Here we report the high-yield solution synthesis of gold nanoribbons in the 4H hexagonal polytype, a previously unreported metastable phase of gold. These gold nanoribbons undergo a phase transition from the original 4H hexagonal to face-centred cubic structure on ligand exchange under ambient conditions. Using monochromated electron energy-loss spectroscopy, the strong infrared plasmon absorption of single 4H gold nanoribbons is observed. Furthermore, the 4H hexagonal phases of silver, palladium and platinum can be readily stabilized through direct epitaxial growth of these metals on the 4H gold nanoribbon surface. Our findings may open up new strategies for the crystal phase-controlled synthesis of advanced noble metal nanomaterials. PMID:26216712

  15. Chemical dynamics of the CH(X2Π) + C2H4(X1A1g), CH(X2Π) + C2D4(X1A1g), and CD(X2Π) + C2H4(X1A1g) reactions studied under single collision conditions.

    PubMed

    Zhang, Fangtong; Maksyutenko, Pavlo; Kaiser, Ralf I

    2012-01-14

    The crossed beam reactions of the methylidyne radical with ethylene (CH(X(2)Π) + C(2)H(4)(X(1)A(1g))), methylidyne with D4-ethylene (CH(X(2)Π) + C(2)D(4)(X(1)A(1g))), and D1-methylidyne with ethylene (CD(X(2)Π) + C(2)H(4)(X(1)A(1g))) were conducted at nominal collision energies of 17-18 kJ mol(-1) to untangle the chemical dynamics involved in the formation of distinct C(3)H(4) isomers methylacetylene (CH(3)CCH), allene (H(2)CCCH(2)), and cyclopropene (c-C(3)H(4)) via C(3)H(5) intermediates. By tracing the atomic hydrogen and deuterium loss pathways, our experimental data suggest indirect scattering dynamics and an initial addition of the (D1)-methylidyne radical to the carbon-carbon double bond of the (D4)-ethylene reactant forming a cyclopropyl radical intermediate (c-C(3)H(5)/c-C(3)D(4)H/c-C(3)H(4)D). The latter was found to ring-open to the allyl radical (H(2)CCHCH(2)/D(2)CCHCD(2)/H(2)CCDCH(2)). This intermediate was found to be long lived with life times of at least five times its rotational period and decomposed via atomic hydrogen/deuterium loss from the central carbon atom (C2) to form allene via a rather loose exit transition state in an overall strongly exoergic reaction. Based on the experiments with partially deuterated reactants, no compelling evidence could be provided to support the formation of the cyclopropene and methylacetylene isomers under single collision conditions. Likewise, hydrogen/deuterium shifts in the allyl radical intermediates or an initial insertion of the (D1)-methylidyne radical into the carbon-hydrogen/deuterium bond of the (D4)-ethylene reactant were found to be-if at all-of minor importance. Our experiments propose that in hydrocarbon-rich atmospheres of planets and their moons such as Saturn's satellite Titan, the reaction of methylidyne radicals should lead predominantly to the hitherto elusive allene molecule in these reducing environments. PMID:22108533

  16. Texas 4-H Agents' Perceptions of Selected Competencies in the 4-H Professional Research, Knowledge, and Competencies Model

    ERIC Educational Resources Information Center

    Harder, Amy; Wingenbach, Gary J.

    2008-01-01

    There are many competencies necessary for success as a 4-H agent. The 4-H Professional Research, Knowledge, and Competencies (PRKC) Model organizes competencies into six domains: (a) Youth Development, (b) Youth Program Development, (c) Volunteerism, (d) Partnerships, (e) Organizational Systems, and (f) Equity, Access and Opportunity (National 4-H…

  17. Fabrication and tests of 3He and 2H targets for beam polarization measurement

    PubMed

    Naqvi; Aksoy; Nagadi; Al-Ohali; Kidwai; Fageeha

    2000-09-01

    3He and 2H targets were fabricated through implantation of 3He and 2H ions in 0.2-0.3 mm thick tantalum and titanium foils. The energy of 3He and 2H ions was 45-100 and 78 keV, respectively. Ions beams with typical current of 90-300 microA were used for implantation. Stability tests of 3He and 2H targets were carried out by monitoring the yield of 3He(d, p)4He and 2H(d, p)3H reactions. For the 3He target, the reaction yield was stable for both tantalum and titanium foils but the most stabilized maximum yield was observed for the 100 keV tantalum target. In the case of 2H targets, the yield increased with increasing total dose implanted on the target. PMID:10972150

  18. Electron paramagnetic resonance spectra and structures of Cu(C sub 2 H sub 4 ), Cu(C sub 2 H sub 4 ) sub 2 , and Cu(C sub 2 H sub 4 ) sub 3 in hydrocarbon matrices

    SciTech Connect

    Howard, J.A.; Joly, H.A.; Mile, B. )

    1990-02-22

    Two mononuclear {pi}-complexes, Cu(C{sub 2}H{sub 4}) and Cu(C{sub 2}H{sub 4}){sub 2}, have been positively identified by EPR spectroscopy from reaction of Cu atoms and ethylene at 77 K in inert hydrocarbon matrices on a rotating cryostat. The spectra of these copper(O) complexes are consistent with dative bonding for both species and with a C{sub 2v} structure for Cu(C{sub 2}H{sub 4}) and a D{sub 2h} structure for Cu(C{sub 2}H{sub 4}){sub 2}. Spectra of Cu({sup 13}CH{sub 2}CH{sub 2}) and Cu({sup 13}CH{sub 2}CH{sub 2}){sub 2} are consistent with these assignments. A third complex is formed in both adamantane and cyclohexane that could be Cu(C{sub 2}H{sub 4}){sub 2} with a structure other than D{sub 2h} but is more likely to be the mononuclear trisligand complex Cu(C{sub 2}H{sub 4}){sub 3} with a D{sub 3h} structure. In the absence of a well-resolved isotropic spectrum of Cu({sup 13}CH{sub 2}CH{sub 2}){sub 3}, this assignment must however be taken as tentative.

  19. Sodium diffusion in 4H-SiC

    SciTech Connect

    Linnarsson, M. K. Hallén, A.

    2014-09-01

    Sodium diffusion has been studied in p-type 4H-SiC. Heat treatments have been performed from 1200 °C to 1800 °C for 1 min to 4 h. Secondary ion mass spectrometry has been used to measure the sodium distribution. We show that sodium has a considerable mobility at 1200 °C in p-type 4H-SiC. On the other hand for sodium atoms trapped at suitable sites the mobility is limited up to 1800 °C. Trap limited diffusion kinetics is suggested and an effective diffusivity has been extracted with an activation energy of 4 eV for sodium diffusion in p-type 4H-SiC.

  20. Thermodynamic Modeling of the SRS Evaporators: Part II. The 3H System

    SciTech Connect

    Jantzen, C.M.

    2001-10-02

    Accumulations of two solid phases have formed scale deposits in the Savannah River Site 2H Evaporator system since late 1996. The aluminosilicate scale deposits caused the evaporator pot to become inoperable in October 1999. Accumulations of the diuranate phase have caused criticality concerns in the SRS 2H Evaporator. In order to ensure that similar deposits are not and will not form in the SRS 3H Evaporator, thermodynamically derived activity diagrams specific to the feeds processed from Tanks 30 and 32 are evaluated in this report.

  1. Isomer Energy Differences for the C4H3 and C4H5 Isomers UsingDiffusion Monte Carlo

    SciTech Connect

    Domin, D.; Lester Jr., W.A.; Whitesides, R.; Frenklach, M.

    2007-12-01

    A new diffusion Monte Carlo study is performed on the isomers of C{sub 4}H{sub 3} and C{sub 4}H{sub 5} emulating the methodology of a previous study [Int. J. Chem. Kinetics 33, 808 (2001)]. Using the same trial wave function form of the previous study, substantially different isomerization energies were found owing to the use of larger walker populations in the present work. The energy differences between the E and I isomers of C{sub 4}H{sub 3} were found to be 10.5 {+-} 0.5 kcal/mol and for C{sub 4}H{sub 5}, 9.7 {+-} 0.6 kcal/mol. These results are in reasonable accord with recent MRCI and CCSD(T) findings.

  2. Infrared spectrum of NH4+(H2O): Evidence for mode specific fragmentation

    SciTech Connect

    Pankewitz, Tobias; Lagutschenkov, Anita; Niedner-schatteburg, Gereon; Xantheas, Sotiris S; Lee, Yuan-Tseh

    2007-02-21

    The gas phase infrared spectrum (3250 to 3810 cm1) of the singly hydrated ammonium ion, NH4+(H2O), has been recorded by consequence spectroscopy of mass selected and isolated ions. The obtained four bands are assigned to N-H stretching modes and O-H stretching modes, respectively. The observed N-H stretching modes are blueshifted with respect to the corresponding modes of the free NH4+ ion, whereas a redshift is observed with respect to the modes of the free NH3 molecule. The observed O-H stretching modes are redshifted when compared to the free H2O molecule. The asymmetric stretching modes give rise to rotationally resolved perpendicular transitions. The K-type equidistant rotational spacings of 11.1(2) cm1 (NH4+) and 29(3) cm1 (H2O) deviate systematically from the corresponding values of the free molecules, a fact which is rationalized in terms of a symmetric top analysis. The recorded relative band intensities compare favorably with predictions of high level ab initio calculations except for the 3(H2O) band for which the observed value is about 20 times weaker than the calculated one. This long standing puzzle motivated us to examine the a 3(H2O)/1(H2O) intensity ratios from other published action spectra in other cationic complexes. These suggest that the 3(H2O) intensities become smaller the stronger the complexes are bound. The recorded ratios vary, in particular among the data collected from action spectra that were recorded with and without rare gas tagging. The calculated anharmonic coupling constants in NH4+(H2O) further suggested that the coupling of the 3(H2O) and 1(H2O) modes to other cluster modes indeed varies by orders of magnitude. These findings altogether render the picture of a mode specific fragmentation dynamic that modulates band intensities in action spectra with respect to absorption spectra. Additional high-level electronic structure calculations at the coupled-cluster single and double with perturbative treatment of triple excitations

  3. Density Functional Exploration of C4H3N Isomers.

    PubMed

    Custer, Thomas; Szczepaniak, Urszula; Gronowski, Marcin; Fabisiewicz, Emilia; Couturier-Tamburelli, Isabelle; Kołos, Robert

    2016-07-28

    Molecules having C4H3N stoichiometry are of astrophysical interest. Two of these, methylcyanoacetylene (CH3C3N) and its structural isomer allenyl cyanide (H2CCCHN), have been observed in interstellar space, while several more have been examined in laboratories. Here we describe, for a broad range of C4H3N isomers, density functional calculations (B3LYP/aug-cc-pVTZ) of molecular parameters including the energetics, geometries, rotational constants, electric dipole moments, polarizabilities, vibrational IR frequencies, IR absorption intensities, and Raman activities. Singlet-triplet splittings as well as singlet vertical electronic excitation energies are given for selected species. The identification of less stable C4H3N molecules, generated in ongoing spectroscopic experiments, relies heavily on these quantum chemical predictions. PMID:27341606

  4. Photodisintegration of /sup 3/H and /sup 3/He. [Threshold to 25 MeV

    SciTech Connect

    Faul, D.D.

    1980-09-01

    The photoneutron cross sections for /sup 3/H and /sup 3/He have been measured from threshold to approx. 25 MeV with monoenergetic photons from the annihilation in flight of fast positrons at the LLL Electron-Positron Linear Accelerator facility. These reactions include the two-body breakup of /sup 3/H and the three-body breakup of both /sup 3/H and /sup 3/He; these measurements for /sup 3/H are the first to span the energy region across the peaks of the cross sections. An efficient BF/sub 3/-tube-and-paraffin neutron detector and high-pressure gaseous samples of several moles each (the activity of the /sup 3/H sample was approx. 200,000 Ci) were employed in these measurements. Measurements on /sup 16/O and /sup 2/H also were performed to verify the absolute cross-section scale. The results, when compared with each other and with results for the two-body breakup cross section for /sup 3/He from the literature, show that the two-body breakup cross sections for /sup 3/H and /sup 3/He have nearly the same shape, but the one for /sup 3/He lies lower in magnitude; the three-body breakup cross section for /sup 3/He lies higher in magnitude and is broader in the peak region and also rises less sharply from threshold than that for /sup 3/H; and these measured differences between the cross sections for the breakup modes largely compensate in their sum, so that the total photon absorption cross sections for /sup 3/H and /sup 3/He are nearly the same in both size and shape at energies near and above their peaks. Theoretical results from the literature disagree with the experimental results to a certain extent over the entire photon-energy region for which the photoneutron cross sections were measured. 50 figures, 7 tables.

  5. Synthetic studies towards putative yuremamine using an iterative C(sp(3))-H arylation strategy.

    PubMed

    Calvert, Matthew B; Sperry, Jonathan

    2016-06-28

    An overview of an iterative, 8-aminoquinoline (AQ)-directed C(sp(3))-H arylation strategy towards the pyrroloindole structure initially assigned to the alkaloid yuremamine is described. During initial efforts using a model indane system, it was discovered that the iodoresorcinol unit was not a viable C(sp(3))-H arylation partner when masked as its dimethyl ether but upon switching to a MOM group, the ether oxygen served to stabilise the high valent Pd intermediate during the reaction, thus promoting reductive elimination and leading to acceptable yields of the C(sp(3))-H arylation product. The second C(sp(3))-H arylation with an iodopyrogallol gave a 1,3-diarylated model yuremamine system possessing the desired 1,3-cis relationship. When the successful model studies were applied to a pyrroloindole system in pursuit of yuremamine, it became apparent that C9 underwent competing C(sp(2))-H arylation if left vacant, but installing a tryptamine side chain at this site prevented the desired C(sp(3))-H arylation from occurring altogether. However, a C9-methyl pyrroloindole underwent iterative C(sp(3))-H arylation at C1 with an iodoresorcinol followed by C3 with an iodopyrogallol to give a diarylated product with the aryl groups in the undesired 1,3-trans-relationship, arising from epimerisation at C1 during the second C(sp(3))-H arylation event. Although the synthesis of putative yuremamine was not accomplished, several findings are disclosed that will serve as useful additions to the burgeoning field of directed C(sp(3))-H arylations and related C-H functionalization reactions. PMID:26891188

  6. Phosphorus balance and mineral metabolism with 3 h daily hemodialysis.

    PubMed

    Ayus, J C; Achinger, S G; Mizani, M R; Chertow, G M; Furmaga, W; Lee, S; Rodriguez, F

    2007-02-01

    Poor control of mineral metabolism is independently associated with mortality in patients receiving hemodialysis. We analyzed data from a 12-month, prospective, non-randomized, controlled study of daily hemodialysis (DHD) (six sessions/week 3 h each) (n=26) vs conventional hemodialysis (CHD) (three sessions/week 4 h each) (n=51) for achievement of mineral metabolism goals and we performed a substudy of weekly dialytic phosphorus removal in DHD vs CHD. Phosphorus control was superior in the DHD group (% change from baseline to end-of-study -27+/-30% vs +7%+/-35% in the CHD group, P=0.0001). Percentage of patients using phosphate binders decreased from 77 to 40% among subjects on DHD, whereas these parameters did not change (76 vs 77%) in the CHD group (P=0.03 by Breslow-Day test for homogeneity of the odds ratios). Weekly mean phosphorus removal was higher in the DHD group (2452+/-720 mg/week vs 1572+/-366 mg/week, P=0.04). Mean normalized protein catabolic rate increased (0.90+/-0.43-1.22+/-0.26 g/kg/day, P=0.0013). DHD was also associated with an increase in the percent of subjects achieving three or more mineral metabolism goals (for phosphorus, calcium x phosphorus and parathyroid hormone) (15 vs 46%, P=0.046). In conclusion, DHD improves phosphorus control by increasing dialytic phosphorus removal while maintaining nutritional status and reducing the use of phosphate binders. The net effect allows for improved achievement of mineral metabolism goals. PMID:17191084

  7. The Big E (Energy). 4-H Member Guide, Unit 2.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 2 (ages 12-14) of the Nebraska 4-H Energy Project. Aims, energy attitudes to be developed, and instructions are provided for each activity. Activities include: (1) a word search of energy-related words (with definitions provided); (2) determining fuel waste; (3) reading electric/gas meters and…

  8. Keys To The Kansas Environment. 4-H School Enrichment Program.

    ERIC Educational Resources Information Center

    Kansas State Univ., Manhattan. Extension Service.

    The 4-H Club packet for preschool and elementary school children contains nine "keys", or short learning exercises, designed to enrich science and environmental education both in and out of the classroom. Each "key" includes the purpose of the activity, the intended audience, the best time of the year for the activity, background information,…

  9. Marketing Strategies for Recruiting 4-H Members in West Virginia.

    ERIC Educational Resources Information Center

    Wingenbach, Gary J.; Nestor, Cheryl; Lawrence, Layle D.; Gartin, Stacy A.; Woloshuk, Jean; Mulkeen, Patricia

    2000-01-01

    According to a survey of 174 West Virginia 4-H members aged 13-18, the Internet and word of mouth were most effective in recruiting new members. Active messages stressing camps, fun, and friendship had the most influence on retention. A statewide marketing plan was recommended. (SK)

  10. Self-Protection: A New Approach to 4-H Health.

    ERIC Educational Resources Information Center

    Wright, Sharon K. B.

    This document introduces the issue of self-protection as the Minnesota 4-H Youth Development response to self-destructive behavior among adolescents. It presents findings from a statewide survey of over 36,000 secondary school students using the Minnesota Adolescent Health Survey. Responses are given in the areas of health, school attitudes,…

  11. CONSERVING OUR NATURAL RESOURCES, A 4-H LEADER'S GUIDE.

    ERIC Educational Resources Information Center

    AMICK, W. ROBERT; AND OTHERS

    AN EFFECTIVE 4-H CONSERVATION PROGRAM IS DEVELOPED AROUND THE FOLLOWING BASIC CONCEPTS--(1) MAN IS A PART OF THE NATURAL WORLD, IN WHICH THERE ARE MANY VALUABLE MATERIALS, (2) MAN HAS LEARNED TO USE MANY OF THOSE MATERIALS FOR HUMAN SUSTENANCE AND BETTERMENT, AND (3) MAN'S ECONOMIC, SOCIAL, AND GENERAL WELFARE IS LARGELY DEPENDENT UPON THE MANNER…

  12. "Ohio 4-H CARTEENS": Peer Intervention Safety Program.

    ERIC Educational Resources Information Center

    Cropper, Rebecca J.

    1999-01-01

    Ohio 4-H's CARTEENS seeks to reduce juvenile traffic violations in a program designed and presented by teen peer educators with guidance and technical assistance from the state highway patrol. Teens examined court data to determine content, which includes defensive driving, rural road safety, and dealing with peer pressure. (SK)

  13. Effectiveness of the Indiana 4-H Tractor Program: Alumni Perceptions.

    ERIC Educational Resources Information Center

    Carrabba, James J., Jr.; Talbert, B. Allen; Field, William E.; Tormoehlen, Roger

    2001-01-01

    Responses from Indiana 4-H tractor driving contestants 1982-197 (n=139) showed that 74% were employed on farms; most felt the contests effectively taught tractor safety and made them generally aware of safety. However, many still engaged in risky behaviors such as not wearing seatbelts in tractors with rollover protective structures or allowing…

  14. The Big E (Energy). 4-H Member Guide, Unit 3.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This activity and record book is designed for unit 3 (ages 15-19) of the Nebraska 4-H Energy Project. Aims, energy attitudes to be developed, and instructions are provided for each activity. Activities include: (1) determining ways to reduce energy waste with hot water heaters; (2) making personal choices about using appliances; (3) conducting a…

  15. A Phenomenological Look at 4-H Volunteer Motives for Service

    ERIC Educational Resources Information Center

    Schrock, Jessalyn; Kelsey, Kathleen D.

    2013-01-01

    Volunteers play a vital role in 4-H programs. Without their service, many programs would not be possible. Understanding volunteer motives provides Extension educators with tools for finding high-quality volunteers. The research reported here used McClelland's (1985) framework for motivation (affiliation, achievement, and power) and…

  16. Minnesota 4-H Youth Program Quality Improvement Model

    ERIC Educational Resources Information Center

    Herman, Margo; Grant, Samantha

    2015-01-01

    The University of Minnesota Extension Center for Youth Development made an organizational decision in 2011 to invest in a system-wide approach to implement youth program quality into the 4-H program using the Youth Program Quality Assessment (YPQA) tool. This article describes the four key components to the Minnesota Youth Program Quality…

  17. The Evaluation Attitudes and Practices of 4-H Educators

    ERIC Educational Resources Information Center

    Lekies, Kristi S.; Bennett, Amanda M.

    2011-01-01

    Extension educators are expected to conduct program evaluation. An Internet survey was sent to county 4-H educators in Ohio to examine their evaluation attitudes and practices, as well as barriers to conducting evaluation. Respondents indicated a range of attitudes about evaluation and limited use of different designs and methods. Having enough…

  18. Fashion Revue. 4-H Textile Science Activity Guide.

    ERIC Educational Resources Information Center

    Scholl, Jan

    This publication was developed to help students participating in Fashion Review, a 4-H event in which students model a clothing outfit and accessories and are judged on their modeling ability, their presentation, and how well the clothing and accessory choices complement the students' skin tones, hair color, figure or physique, personality, and…

  19. Differential binding of /sup 3/H-imipramine and /sup 3/H-mianserin in rat cerebral cortex

    SciTech Connect

    Dumbrille-Ross, A.; Tang, S.W.; Coscina, D.V.

    1981-11-16

    Drug competition profiles, effect of raphe lesion, and sodium dependency of the binding of two antidepressant drugs /sup 3/H-imipramine and /sup 3/H-mianserin to rat cerebral cortex homogenate were compared to examine whether the drugs bound to a common ''antidepressant receptor.'' Of the neurotransmitters tested, only serotonin displaced binding of both /sup 3/H-imipramine and /sup 3/H-mianserin. /sup 3/H-Mianserin binding was potently displaced by serotonin S/sub 2/ antagonists and exhibited a profile similar to that of /sup 3/H-spiperone binding. In the presence of the serotonin S/sub 2/ antagonist spiperone, antihistamines (H/sub 1/) potently displaced /sup 3/H-mianserin binding. /sup 3/H-Imipramine binding was displaced potently by serotonin uptake inhibitors. The order of potency of serotonergic drugs in displacing /sup 3/H-imipramine binding was not similar to their order in displacing /sup 3/H-spiperone or -3H-serotonin binding. Prior midbrain raphe lesions greatly decreased the binding of /sup 3/H-imipramine but did not alter binding of /sup 3/H-mianserin. Binding of /sup 3/H-imipramine but not /sup 3/H-mianserin was sodium dependent. These results show that /sup 3/H-imipramine and /sup 3/H-mianserin bind to different receptors. /sup 3/H-Imipramine binds to a presynaptic serotonin receptor which is probably related to a serotonin uptake recognition site, the binding of which is sodium dependent. /sup 3/H-Mianserin binds to postsynaptic receptors, possibly both serotonin S/sub 2/ and histamine H/sub 1/ receptors, the binding of which is sodium independent.

  20. Composition of saturn's atmosphere at northern temperate latitudes from Voyager iris spectra: NH/sub 3/, PH/sub 3/, C/sub 2/H/sub 2/, C/sub 2/H/sub 6/, CH/sub 3/D, CH/sub 4/, and the saturnian D/H isotopic ratio

    SciTech Connect

    Courtin, R.; Gautier, D.; Marten, A.; Bezard, B.; Hanel, R.

    1984-12-15

    The abundances of minor atmospheric constituents at northern Saturnian latitudes have been inferred from infrared emission spectra recorded by Voyager. The NH/sub 3/, PH/sub 3/, C/sub 2/H/sub 2/, and C/sub 2/H/sub 6/ vertical distributions have been determined from spectra selected in a cloud-free region centered approximately at the latitude of the Voyager 2 radio-occultation point (36.5 N). The NH/sub 3/ mixing ratio in the upper troposphere is found to be compatible with the saturated partial pressure. The inferred PH/sub 3//H/sub 2/ ratio of 1.4 +- 0.8 x 10/sup -6/ is higher than the value derived from the solar P/H ratio, and the PH/sub 3/ vertical profile may extend somewhat into the stratosphere, up to a few millibars. The stratospheric C/sub 2/H/sub 2//H/sub 2/ and C/sub 2/H/sub 6//H/sub 2/ ratios are, respectively, 2.1 +- 1.4 x 10/sup -7/ and 3.0 x 1.1 x 10/sup -6/; the latter decreases sharply below the 20-50 mbar level. A larger selection of spectra yields CH/sub 3/D/H/sub 2/ = 3.9 +- 2.5 x 10/sup -7/ and CH/sub 4//H/sub 2/ = 4.5/sup +2.4//sub -1.9/ x 10/sup -3/. This result implies an enrichment of Saturn's upper atmosphere is carbon by at least a factor of 3 over the solar abundance. The D/H value resulting from our CH/sub 3/D/CH/sub 4/ ratio is 1.6/sup +1.3//sub -1.2/ x 10/sup -5/, significantly lower than previous determinations obtained from HD lines; it is also less than half of the IRIS-inferred Jovian value. Finally, the interpretation of two NH/sub 3/ lines in the 5 ..mu..m window suggests a NH/sub 3/H/sub 2/ ratio at the 2 bar level below the solar value.

  1. Chloride-based fast homoepitaxial growth of 4H-SiC films in a vertical hot-wall CVD

    NASA Astrophysics Data System (ADS)

    Guoguo, Yan; Feng, Zhang; Yingxi, Niu; Fei, Yang; Xingfang, Liu; Lei, Wang; Wanshun, Zhao; Guosheng, Sun; Yiping, Zeng

    2016-06-01

    Chloride-based fast homoepitaxial growth of 4H-SiC epilayers was performed on 4° off-axis 4H-SiC substrates in a home-made vertical hot-wall chemical vapor deposition (CVD) system using H2‑SiH4‑C2H4‑HCl. The effect of the SiH4/H2 ratio and reactor pressure on the growth rate of 4H-SiC epilayers has been studied successively. The growth rate increase in proportion to the SiH4/H2 ratio and the influence mechanism of chlorine has been investigated. With the reactor pressure increasing from 40 to 100 Torr, the growth rate increased to 52 μm/hand then decreased to 47 μm/h, which is due to the joint effect of H2 and HCl etching as well as the formation of Si clusters at higher reactor pressure. The surface root mean square (RMS) roughness keeps around 1 nm with the growth rate increasing to 49 μm/h. The scanning electron microscope (SEM), Raman spectroscopy and X-ray diffraction (XRD) demonstrate that 96.7 μm thick 4H-SiC layers of good uniformity in thickness and doping with high crystal quality can be achieved. These results prove that chloride-based fast epitaxy is an advanced growth technique for 4H-SiC homoepitaxy. Project supported by the National High Technology R&D Program of China (No. 2014AA041402), the National Natural Science Foundation of China (Nos. 61474113, 61274007, 61574140), the Beijing Natural Science Foundation of China (Nos. 4132076, 4132074), the Program of State Grid Smart Grid Research Institute (No. SGRI-WD-71-14-004), and the Youth Innovation Promotion Association of CAS.

  2. Unimolecular reaction mechanisms involving C sub 3 H sub 4 , C sub 4 H sub 4 , and C sub 6 H sub 6 hydrocarbon species

    SciTech Connect

    Melius, C.F.; Miller, J.A. ); Evleth, E.M. . Dynamique des Interactions Moleculaires)

    1991-01-01

    The unimolecular rearrangement processes of unsaturated aliphatic hydrocarbons representative of intermediates in rich hydrocarbon flames have been investigated using the quantum chemical BAC-MP4 method. In particular, we have investigated the unimolecular reaction mechanisms involving (1) allene-cyclopropene-propyne rearrangement, (2) vinylacetylene pyrolysis leading to acetylene and diacetylene, and (3) various C{sub 6}H{sub 6} compounds, including 1,5-hexadiyne, 1,2,4,5-hexatetraene, and 1,2-hexadin-5-yne leading to 3,4-dimethylenecyclobutene, fulvene, benzene, 2-ethynyl-1,3-butadiene, and other C{sub 6}H{sub 6} species. Rate constants for various reaction steps give food agreement with available experimental measurements. The reaction mechanisms are also consistent with various deuterium isotope labeling experiments. The results indicate that many different types of reaction mechanisms occur, including concerted pathways involving carbene and vinylidene intermediates and insertion reactions of vinylidenes into C-H bonds and C-C multiple bonds. New decomposition pathways are presented for vinylacetylene pyrolysis, for conversion of 1,2-hexadien-5-yne to fulvene, and for conversion of fulvene to benzene.

  3. On the growth of ternary system HNO{sub 3}/H{sub 2}SO{sub 4}/H{sub 2} aerosol particles in the stratosphere

    SciTech Connect

    Hamill, P.; Tabazadeh, A.; Kinne, S.; Toon, O.B.

    1996-04-01

    The authors present model study results on the formation of ternary aerosols of nitric acid, sulfuric acid, and water in the stratosphere. The aerosol particles grow by means of a heteromolecular condensation process. The authors assume the particles are in equilibrium with the background water vapor.

  4. Water Worlds. 4-H Member's Guide M-5-18; 4-H Leaders Guide L-5-18.

    ERIC Educational Resources Information Center

    Hawkes, Janet E.; And Others

    This pocket folder of materials is designed to provide children aged 9 to 12 with an opportunity to explore and observe aquatic environments. The package includes a 4-H Leader's guide, member's guide, and supplementary materials. The leader's guide contains safety considerations, tips and techniques, and additional activities for getting started…

  5. New Jersey 4-H Goat Extravaganza: Efficiently Meeting the Educational Needs of 4-H Goat Project Members, Volunteers, and Parents

    ERIC Educational Resources Information Center

    Ripberger, Chad

    2014-01-01

    The 4-H Goat Extravaganza maximizes limited resources to help youth and adults develop knowledge and skills in goat care and management. It capitalizes on the talents and interests of volunteers to efficiently combine a goat-themed art show, team presentation contest, quiz bowl, skillathon, and adult workshop into 1 day. This article outlines the…

  6. Starting and Maintaining a Marine Aquarium: 4-H Members Guide [and] 4-H Member's Project Record Book.

    ERIC Educational Resources Information Center

    Crenshaw, Neil

    The guide and the project record book included in this document are designed for 4-H members who would like to start a salt-water aquarium project. The guide includes the following topics: (1) general requirements for salt-water aquariums; (2) directions for making an aquarium; (3) suggestions for where to locate it; (4) pros and cons of using…

  7. Litter Control Achievement - Ohio 4-H Club Score Sheet [and] Activity Guides 1 through 7. 4-H Pilot Program 918.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Cooperative Extension Service.

    Seven activity guides, evaluation sheet, and club scoresheet have been prepared for Ohio 4-H clubs' litter education program. Topics of the seven activity guides include: (1) general guidelines and types of activities; (2) little known facts about waste/litter; (3) guidelines for a walking tour; (4) fact sheet (questionnaire) related to garbage;…

  8. Pressure Effects on Product Channels of the Allyl Radical Reactions; C3H5+C3H5 and C3H5+CH3

    NASA Astrophysics Data System (ADS)

    Halpern, J. B.; N'Doumi, M.; Fahr, A.

    2011-12-01

    Relatively large hydrocarbon molecules (C4, C6 and larger) have been detected in several planetary environments. The mechanism for the formation of such large molecular species and detailed mechanism for their potential destruction are not well understood and are of considerable current interest. Previously we have studied the kinetics and product channels of small unsaturated hydrocarbon radical (C2 and C3s) reactions relevant to planetary atmospheric modeling. Reactions of C2 radicals (such as vinyl, H2CCH and ethynyl C2H) and C3 radicals (such as propargyl, HCCCH2) can affect the abundances of a large number of stable observable C3, C4, C5, C6 and larger molecules, including linear, aromatic and even poly aromatic molecules. Pressure-dependent product yields have been determined experimentally for the self- and cross-radical reactions performed at 298 K and at pressures between ~4 Torr (0.5 kPa) and 760 Torr (101 kPa). Final reaction products were quantitatively determined using a gas chromatograph with mass spectrometry/flame ionization detection (GC/MS/FID). In some cases complementary computational studies extended the pressure and temperature range of the experiments and provided valuable information on the complex reaction mechanisms. Theses studies provide a systematic framework so that important energetic and structural parameters for radical-radical reactions can be assessed. Here we report recent results for the allyl radical reactions H2CCCH3+ H2CCCH3 and H2CCCH3+CH3. For the allyl radical self-reaction, at high pressures the "head -to-head", combination channel forming 1,5-hexadiene is dominant with a combination/disproportionation = 1,5-hexadiene/propyne ratio of about 24 at 500 Torr (67 kPa, T=298K). At low pressures the ratio is substantially reduced to about 1.2 (at 0.3 kPa) and other major products are observed including allene, propene, 1-butene and propyne.

  9. Phosphorus implantation into 4H-silicon carbide

    SciTech Connect

    Capano, M.A.; Santhakumar, R.; Venugopal, R.; Melloch, M.R.; Cooper, J.A. Jr.

    2000-02-01

    Sheet resistances in nitrogen- and phosphorus-implanted 4H-SiC are measured to assess the time and temperature dependencies of this variable. In 4H-SiC implanted with 3 x 10{sup 15} cm{sup {minus}2} nitrogen ions to a depth of 2,800 {angstrom}, the minimum sheet resistance observed is 534 {Omega}/{open{underscore}square}, a record low value for any implanted element into any polytype of SiC. Time-independent sheet resistances are observed following anneals at 1,700 C for nitrogen and phosphorus samples. Lower temperature anneals produce sheet resistances which decrease monotonically with increasing time of anneal. Overall, sheet resistances from phosphorus-implanted 4H-SiC are an order of magnitude below those measured from nitrogen implanted samples. The response of phosphorus to low-temperature annealing is significant, and sheet resistances below 500 {Omega}/{open{underscore}square} are achieved at 1,200 C. Activation of phosphorus is attempted in an oxidizing atmosphere with and without prior argon annealing. A three-hour gate oxidation in wet O{sub 2} at 1,150 C, followed by a 30 min argon anneal, produced a sheet resistance of 1081 {Omega}/{open{underscore}square}. Oxidation after argon annealing caused sheet resistances to increase by about 20% compared to samples subjected solely to argon annealing. It is also found that oxide growth rates are much higher over phosphorus implanted than over unimplanted 4H-SiC. Reasons for the disparity in sheet resistances between nitrogen and phosphorus implants, and for the difference in oxide growth rates are suggested.

  10. A Perfect Fit: 4-H Involvement for Youth with Disabilities. A Leader's Guide.

    ERIC Educational Resources Information Center

    Schnepf, Greg W.; And Others

    This guide for 4-H leaders and volunteers offers information to help integrate youth with disabilities into various 4-H programs. After an introduction, a section on 4-H and mainstreaming reviews the mission of 4-H; considers what 4-H has to offer youth; defines mainstreaming; notes the benefits of mainstreaming; and distinguishes among the terms…

  11. Mass spectrum of the 1-butene-3-yne-2-yl radical (i-C4H3; X2A')

    NASA Astrophysics Data System (ADS)

    Guo, Ying; Gu, Xibin; Kaiser, Ralf I.

    2006-03-01

    The crossed molecular beams method has been applied to produce the 1-butene-3-yne-2-yl radical, i-C4H3(X2A') under single collision conditions via the reaction of dicarbon molecules with ethylene. We recorded time-of-flight spectra of the radical at the center-of-mass angle (28.0°) of the parent ion (m/z = 51; C4H3+) and of the fragments at m/z = 50 (C4H2+), m/z = 49 (C4H+), m/z = 48 (C4+), m/z = 39 (C3H3+), m/z = 38 (C3H2+), m/z = 37 (C3H+), and m/z = 36 (C3+). This yielded relative intensity ratios of I(m/z = 51):I(m/z = 50):I(m/z = 49):I(m/z = 48):I(m/z = 39):I(m/z = 38):I(m/z = 37):I(m/z = 36) = 0.47 +/- 0.01:0.94 +/- 0.01:1.0:0.07 +/- 0.02:0.31 +/- 0.01:0.23 +/- 0.02:0.24 +/- 0.01:0.12 +/- 0.01 at 70 eV electron impact energy. Upper limits at mass-to-charge ratios between 27 and m/z = 24 and m/z = 14-12 were derived to be 0.02 +/- 0.01. Note that the intensity of the 13C isotopic peak of the 1-butene-3-yne-2-yl radical at m/z = 52 (13C12C3H3+) is about 0.04 +/- 0.01 relative to m/z = 51. Employing linear scaling methods, the absolute electron impact ionization cross section of the 1-butene-3-yne-2-yl radical was computed to be 7.8 +/- 1.6 × 10-16 cm2. These data can be employed to monitor the 1-butene-3-yne-2-yl radical in oxygen-poor combustion flames and in the framework of prospective explorations of planetary atmospheres (Jupiter, Saturn, Uranus, Neptune, Pluto) and of their moons (Titan, Triton, Oberon) in situ via matrix interval arithmetic assisted mass spectrometry.

  12. Comparison of (/sup 3/H)nicotine and (/sup 3/H)acetylcholine binding in mouse brain: regional distribution

    SciTech Connect

    Sershen, H.; Reith, M.E.; Hashim, A.; Lajtha, A.

    1985-06-01

    In a continuing study of nicotine binding sites, the authors determined the relative amount of nicotine binding and acetylcholine binding in various brain regions of C57/BL and of DBA mice. Although midbrain showed the highest and cerebellum the lowest binding for both (/sup 3/H)nicotine and (/sup 3/H)acetylcholine, the ratio of nicotine to acetylcholine binding showed a three-fold regional variation. Acetylcholine inhibition of (/sup 3/H)nicotine binding indicated that a portion of nicotine binding was not inhibited by acetylcholine. These results indicate important differences between the binding of (+/-)-(/sup 3/H)nicotine and that of (/sup 3/H)acetylcholine.

  13. Single freezing and triple melting of micrometre-scaled (NH4)2SO4/H2O droplets.

    PubMed

    Bogdan, Anatoli; Molina, Mario J; Tenhu, Heikki; Loerting, Thomas

    2011-11-28

    Atmospheric aerosol droplets containing NH(4)(+) and SO(4)(2-) ions are precursors of cirrus ice clouds. However, the low-temperature phase transformation of such droplets is not understood yet. Here we show for the first time that micrometre-scaled (NH(4))(2)SO(4)/H(2)O droplets produce one freezing event but three melting events which are the melting of (i) pure ice, (ii) eutectic ice/(NH(4))(2)SO(4), and (iii) eutectic ice/(NH(4))(3)H(SO(4))(2). We also find that the melting of ice/(NH(4))(3)H(SO(4))(2) consists of two eutectic melting events, presumably ice/letovicite-II and ice/letovicite-III. PMID:21842051

  14. Anionic ordering and thermal properties of FeF3·3H2O.

    PubMed

    Burbano, Mario; Duttine, Mathieu; Borkiewicz, Olaf; Wattiaux, Alain; Demourgues, Alain; Salanne, Mathieu; Groult, Henri; Dambournet, Damien

    2015-10-01

    Iron fluoride trihydrate can be used to prepare iron hydroxyfluoride with the hexagonal-tungsten-bronze (HTB) type structure, a potential cathode material for batteries. To understand this phase transformation, a structural description of β-FeF3·3H2O is first performed by means of DFT calculations and Mössbauer spectroscopy. The structure of this compound consists of infinite chains of [FeF6]n and [FeF2(H2O)4]n. The decomposition of FeF3·3H2O induces a collapse and condensation of these chains, which lead to the stabilization, under specific conditions, of a hydroxyfluoride network FeF3-x(OH)x with the HTB structure. The release of H2O and HF was monitored by thermal analysis and physical characterizations during the decomposition of FeF3·3H2O. An average distribution of FeF4(OH)2 distorted octahedra in HTB-FeF3-x(OH)x was obtained subsequent to the thermal hydrolysis/olation of equatorial anionic positions involving F(-) and H2O. This study provides a clear understanding of the structure and thermal properties of FeF3·3H2O, a material that can potentially bridge the recycling of pickling sludge from the steel industry by preparing battery electrodes. PMID:26378743

  15. Anionic ordering and thermal properties of FeF3·3H2O

    DOE PAGESBeta

    Burbano, Mario; Duttine, Mathieu; Borkiewicz, Olaf; Wattiaux, Alain; Demourgues, Alain; Salanne, Mathieu; Groult, Henri; Dambournet, Damien

    2015-09-17

    In this study, iron fluoride tri-hydrate can be used to prepare iron hydroxyfluoride with the Hexagonal-Tungsten-Bronze (HTB) type structure, a potential cathode material for batteries. To understand this phase transformation, a structural description of β-FeF3·3H2O is first performed by means of DFT calculations and Mössbauer spectroscopy. The structure of this compound consists of infinite chains of [FeF6]n and [FeF2(H2O)4]n. The decomposition of FeF3·3H2O induces a collapse and condensation of these chains, which lead to the stabilization, under specific conditions, of a hydroxyfluoride network FeF3-x(OH)x with the HTB structure. The release of H2O and HF was monitored by thermal analysis andmore » physical characterizations during the decomposition of FeF3·3H2O. An average distribution of FeF4(OH)2 distorted octahedra in HTB-FeF3-x(OH)x was obtained subsequent to the thermal hydrolysis/olation of equatorial anionic positions involving F- and H2O. This study provides a clear understanding of the structure and thermal properties of FeF3·3H2O, a material that can potentially bridge the recycling of pickling sludge from the steel industry by preparing battery electrodes.« less

  16. Synthesis and characterization of 3H-labelled tetrahydrobiopterin.

    PubMed Central

    Werner, E R; Schmid, M; Werner-Felmayer, G; Mayer, B; Wachter, H

    1994-01-01

    We synthesized [3'-3H]-5,6,7,8-tetrahydrobiopterin from [8,5'-3H]guanosine 5'-triphosphate ([8,5'-3H]GTP) using GTP cyclohydrolase (EC 3.5.4.16), 6-pyruvoyltetrahydropterin synthase and sepiapterin reductase (EC 1.1.1.153). After purification by cation-exchange h.p.l.c. a solution of radiochemically pure (> 95%) [3'-3H]-5,6,7,8-tetrahydrobiopterin with a specific activity of 9.2 Ci/mmol was obtained. The product proved well suited for studying the binding of tetrahydrobiopterin to nitric-oxide synthase. PMID:7528005

  17. (3)H activity comparison between FTMC, VNIIM and LNE-LNHB.

    PubMed

    Cassette, Philippe; Butkus, Paulius; Gudelis, Arunas; Shilnikova, Tatiana

    2016-03-01

    An activity comparison of tritiated water was organized in 2013 between 3 laboratories: FTMC (Lithuania), LNE-LNHB (France) and VNIIM (Russia). The solution was prepared by LNHB and ampoules were sent to the others laboratories. This solution was standardized in terms of activity per unit mass by participant laboratories using the Triple to Double Coincidence Ratio (TDCR) method in liquid scintillation counting (LSC). The tritiated water solution is traceable to the solution prepared by LNHB for the CCRI(II)-K2.H-3 2009 (3)H international comparison. PMID:26651170

  18. Dissociative recombination of N2H+

    NASA Astrophysics Data System (ADS)

    dos Santos, S. Fonseca; Ngassam, V.; Orel, A. E.; Larson, Å.

    2016-08-01

    The direct and indirect mechanisms of dissociative recombination of N2H+ are theoretically studied. At low energies, the electron capture is found to be driven by recombination into bound Rydberg states, while at collision energies above 0.1 eV, the direct capture and dissociation along electronic resonant states becomes important. Electron-scattering calculations using the complex Kohn variational method are performed to obtain the scattering matrix as well as energy positions and autoionization widths of resonant states. Potential-energy surfaces of electronic bound states of N2H and N2H+ are computed using structure calculations with the multireference configuration interaction method. The cross section for the indirect mechanism is calculated using a vibrational frame transformation of the elements of the scattering matrix at energies just above the ionization threshold. Here vibrational excitations of the ionic core from v =0 to v =1 and v =2 for all three normal modes are considered and autoionization is neglected. The cross section for the direct dissociation along electronic resonant states is computed with wave-packet calculations using the multiconfiguration time-dependent Hartree method, where all three internal degrees of freedom are considered. The calculated cross sections are compared to measurements.

  19. Crystal structure of 4-benzyl-2H-benzo[b][1,4]thia­zin-3(4H)-one

    PubMed Central

    Sebbar, N. K.; Ellouz, M.; Essassi, E. M.; Ouzidan, Y.; Mague, J. T.

    2015-01-01

    In the title compound, C15H13NOS, the thia­zine ring adopts a twisted boat conformation and the dihedral angle between the aromatic rings is 86.54 (4)°. In the crystal, mol­ecules are linked by weak C—H⋯O inter­actions, resulting in chains along [010]. PMID:26870571

  20. 4-Substituted 2-Hydroxyisoquinoline-1,3(2H,4H)-diones as a Novel Class of HIV-1 Integrase Inhibitors.

    PubMed

    Billamboz, Muriel; Suchaud, Virginie; Bailly, Fabrice; Lion, Cedric; Demeulemeester, Jonas; Calmels, Christina; Andréola, Marie-Line; Christ, Frauke; Debyser, Zeger; Cotelle, Philippe

    2013-07-11

    A series of 2-hydroxy-1,3-dioxoisoquinoline-4-carboxamides featuring an N-hydroxyimide chelating functionality was evaluated for their inhibitory properties against human immunodeficiency virus type 1 integrase (HIV-1 IN). Several derivatives displayed low nanomolar IC50 values comparable to that of the clinically used raltegravir. A marked effect of one compound on both primary IN-catalyzed reactions, strand transfer (ST), and 3' processing (3'-P), emphasizes a novel IN inhibition mechanism establishing it as a potential new generation IN inhibitor. Substitution of the 2-hydroxyisoquinoline-1,3-dione scaffold at position 4 by carboxamido chains was beneficial for antiviral activity since reproducible low micromolar anti-HIV activities were obtained for the first time within this scaffold. PMID:24900718

  1. 4-Substituted 2-Hydroxyisoquinoline-1,3(2H,4H)-diones as a Novel Class of HIV-1 Integrase Inhibitors

    PubMed Central

    2013-01-01

    A series of 2-hydroxy-1,3-dioxoisoquinoline-4-carboxamides featuring an N-hydroxyimide chelating functionality was evaluated for their inhibitory properties against human immunodeficiency virus type 1 integrase (HIV-1 IN). Several derivatives displayed low nanomolar IC50 values comparable to that of the clinically used raltegravir. A marked effect of one compound on both primary IN-catalyzed reactions, strand transfer (ST), and 3′ processing (3′-P), emphasizes a novel IN inhibition mechanism establishing it as a potential new generation IN inhibitor. Substitution of the 2-hydroxyisoquinoline-1,3-dione scaffold at position 4 by carboxamido chains was beneficial for antiviral activity since reproducible low micromolar anti-HIV activities were obtained for the first time within this scaffold. PMID:24900718

  2. Partial chemical characterization of cyclopyrrolones ((/sup 3/H) suriclone) and benzodiazepines ((/sup 3/H)flunitrazepam) binding site: Differences

    SciTech Connect

    Zundel, J.L.; Blanchard, J.C.; Julou, L.

    1985-06-10

    Rat hippocampus membranes were treated with several protein modifying reagents (iodoacetamide, N-ethylmaleimide, tetranitromethane and N-acetylimidazole). The effects of these treatments on the binding sites of cyclopyrrolones ((/sup 3/H) suriclone), a new chemical family of minor tranquilizers, and benzodiazepines ((/sup 3/H) flunitrazepam) were investigated. Here the authors show that both ligands are similarly sensitive to cysteine alkylation: (/sup 3/H) suriclone and (/sup 3/H) flunitrazepam binding are reduced by iodoacetamide and slightly increased by N-ethylmaleimide. On the contrary they are clearly differentiated by tyrosine modification: (/sup 3/H) suriclone binding is not changed whereas (/sup 3/H) flunitrazepam binding is increased by tetranitromethane and decreased by N-acetylimidazole. The present findings and published evidence suggest cyclopyrrolones and benzodiazepines bind to distinct sites or to different allosteric forms of the benzodiazepine receptor. 28 references, 6 figures.

  3. Group theoretical analysis of the H3+ +H2 ↔ H5+ reaction

    NASA Astrophysics Data System (ADS)

    Lin, Zhou

    2016-06-01

    The H3+ +H2 →H2 + H3+ proton transfer reaction is complicated due to the proton scrambling from the large amplitude motions in the H5+ intermediate. In order to understand this reaction, high-resolution spectroscopic studies are necessary for the reactants/products and the intermediate, and the group theoretical analysis is an essential aspect in the prediction and interpretation of these spectra. With five indistinguishable protons, H5+ is characterized using the G240 complete nuclear permutation-inversion (CNPI) group. For most of the configurations sampled by the reaction path, the feasible permutations depend on the distance between the H3+ and H2 fragments. Subgroups of G240 can be used to describe these feasible permutations. Specifically, we consider two limits of the molecular configurations. The equilibrium structure of H5+ , i.e., [H2 -H -H2 ]+, can be described using the G16 molecular symmetry group, while the dissociation products, i.e., H3+ ⋯H2 , require the G24 molecular symmetry group. In the present study, a group theoretical analysis is performed for both limits, providing the symmetries for the nuclear spins and rovibrational wave functions. Also, spectroscopic properties for [H2 -H -H2 ]+, particularly rovibrational couplings and electric dipole selection rules, as well as correlations of energy levels between [H2 -H -H2 ]+ and H3+ ⋯H2 , are obtained.

  4. Intergenerational Panels at Centennial Events: Stimulating Discussion about Continuity and Change in the 4-H Program

    ERIC Educational Resources Information Center

    Kaplan, Matthew S.; Weikert, Ben; Scholl, Jan; Rushton, Mya

    2013-01-01

    This article introduces an intergenerational strategy for organizations planning centennial celebratory events. The methods and findings from the 4-H through the Generations session conducted at the joint 4-H Leadership Conference and 4-H Leaders Forum to celebrate the Pennsylvania 4-H Centennial are reported. Youth and adult participants shared…

  5. North Central Region 4-H Volunteers: Documenting Their Contributions and Volunteer Development

    ERIC Educational Resources Information Center

    Nippolt, Pamela Larson; Pleskac, Sue; Schwartz, Vicki; Swanson, Doug

    2012-01-01

    Documenting volunteer contributions strengthens Extension partnerships with volunteers. A team of North Central Region 4-H volunteer specialists collaborated to conduct a study of 4-H volunteer contributions and impacts related to working with youth within the 4-H program. Over three thousand (3,332) 4-H volunteers from throughout the 12-state…

  6. Parkinson's disease: decreased density of /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites in putamen

    SciTech Connect

    Raisman, R.; Cash, R.; Agid, Y.

    1986-04-01

    The density of high-affinity /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites (two serotonin-uptake blockers) was decreased in the putamen of parkinsonian patients. The correlation between serotonin levels and the number of /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites suggests that they are located on serotoninergic nerve terminals and could be used to study serotoninergic innervation in the human brain. Since imipramine and paroxetine are powerful antidepressants, these results furthermore suggest that decreased serotoninergic transmission may be implicated in the pathophysiology of depression in Parkinson's disease.

  7. Experimental investigations of the hypernucleus Λ4H

    NASA Astrophysics Data System (ADS)

    Achenbach, P.; Schulz, F.; Aulenbacher, S.; Beričič, J.; Bleser, S.; Böhm, R.; Bosnar, D.; Correa, L.; Distler, M. O.; Esser, A.; Fonvieille, H.; Friščić, I.; Fujii, Y.; Fujita, M.; Gogami, T.; Kanda, H.; Kaneta, M.; Kegel, S.; Kohl, Y.; Kusaka, W.; Margaryan, A.; Merkel, H.; Mihovilovič, M.; Müller, U.; Nagao, S.; Nakamura, S. N.; Pochodzalla, J.; Sanchez Lorente, A.; Schlimme, B. S.; Schoth, M.; Sfienti, C.; Širca, S.; Steinen, M.; Takahashi, Y.; Tang, L.; Thiel, M.; Tsukada, K.; Tyukin, A.; Weber, A.

    2016-03-01

    Negatively charged pions from two-body decays of stopped Λ4H hypernuclei were studied in 2012 at the Mainz Microtron MAMI, Germany. The momenta of the decay-pions were measured with unprecedented precision by using high-resolution magnetic spectrometers. A challenge of the experiment was the tagging of kaons from associated K+∧ production off a Be target at very forward angles. In the year 2014, this experiment was continued with a better control of the systematic uncertainties, with better suppression of coincident and random background, improved particle identification, and with higher luminosities. Another key point of the progress was the improvement in the absolute momentum calibration of the magnetic spectrometers.

  8. 4H-SiC detectors for ultraviolet light monitoring

    NASA Astrophysics Data System (ADS)

    Mazzillo, M.; Sciuto, A.; Badalà, P.; Carbone, B.; Russo, A.; Coffa, S.

    2015-02-01

    Silicon Carbide (SiC) provides the unique property of near-perfect visible blindness and very high signal-to-noise ratio due to the high quantum efficiency and low dark current even at high temperature. These features make SiC the best available material for the manufacturing of visible blind semiconductor ultraviolet (UV) light detectors. Thanks to their properties, SiC detectors have been extensively used in fact for flame detection monitoring, UV sterilization and astronomy. Here we report on the electrical and optical performance of patterned thin metal film NiSi/4H-SiC vertical Schottky photodiodes with different semiconductor exposed area suitably designed for UV light monitoring.

  9. Extended defects in 4H-silicon carbide homoepitaxial layers

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan

    The purpose of this thesis is to study the structure of extended defects in 4H-SIC homoepitaxial layers, and to identify their nucleation mechanisms. Characteristics of basal plane dislocations in 4H-SiC epilayers were investigated in a comprehensive manner, including their morphologies, Burgers' vectors, positions, and correlation with the extended defects propagating from the substrate. Plan-view transmission x-ray topography was the major characterization technique used in this study. Complementary data was obtained by KOH etching and optical microscopy. Trace of glide was detected on every basal plane dislocation in the entire 3-inch epilayer. In the center area of the epi-wafer, the glide can extend to macroscopic distance and form edge-type dislocations at the epilayer/surface interface. During the motion, dislocation half loop arrays were found to nucleate at the growth front. The magnitude of the resolved shear stress was estimated based on the radius of curvature of the dislocation lines. It surpassed the critical resolved shear stress at the epitaxial growth temperature. The stress was identified to be compressive in the epilayer. Its origin was studied. Nitrogen-doping-difference-induced misfit strain was excluded as the source of the stress. The structures of two morphological defects, 'carrots' and 'arrows', were studied. Cross-section x-ray topography was used to image the structure of carrot defect in whole. The defect was found to nucleate at the epilayer/substrate interface on a threading screw dislocation propagating from the substrate. Its structure was mainly composed of a prismatic stacking fault and a Frank-type basal plane stacking fault. The arrow defect was found to be produced by a spheroid shape inclusion in the volume of the epilayer. Zone axis diffraction pattern under transmission electron microscope identified the nature of the inclusion as 3C-SIC. It was determined to nucleate at the substrate surface contaminations.

  10. New zinc-glycine-iodide complexes as a product of equilibrium and non-equilibrium crystallization in the Gly - ZnI2 - H2O system

    NASA Astrophysics Data System (ADS)

    Tepavitcharova, S.; Havlíček, D.; Matulková, I.; Rabadjieva, D.; Gergulova, R.; Plocek, J.; Němec, I.; Císařová, I.

    2016-09-01

    Equilibrium crystallization of two anhydrous complex compounds, [Zn(gly)2I2] and [Zn(gly)I2], and non-equilibrium crystallization of the [Zn3(H2O)4(μ-gly)2I6] complex have been observed in the Gly - ZnI2 - H2O system at 25°C. Different mixed zinc-glycine-iodide-aqua complexes exist in the studied solutions and those with the highest activity are responsible for the crystallization process. The stable [ZnI2O2(2Gly)]0 complexes are responsible for the large equilibrium crystallization field of the compound [Zn(gly)2I2] (monoclinic system, C2/c space group), in whose crystal structure they are incorporated as discrete distorted electroneutral tetrahedra. In zinc-iodide solutions with a low water activity it is more probable that the glycine zwitterions act as bidentate ligands and form polynuclear complexes. We assume the [ZnI2O2(2/2Gly)]0 infinite chains build the compound [Zn(gly)I2], for which we have found a narrow equilibrium crystallization field. We have failed to describe the crystal structure of this compound because of its limited stability in the air. Non-equilibrium crystallization of [Zn3(H2O)4(μ-gly)2I6] (triclinic system, P-1 space group) was demonstrated, with crystal structure built by trinuclear complexes [ZnI3O(1/2Gly)] [ZnO4(4H2O)O2(2/2Gly)(trans)][ZnI3O(1/2Gly)]. The FTIR and Raman spectra and also the thermal behaviour of the three compounds were discussed.

  11. High resolution, low temperature photoabsorption cross-section of C2H2 with application to Saturn's atmosphere

    NASA Technical Reports Server (NTRS)

    Caldwell, John; Wu, C. Y. R.; Xia, T. J.; Judge, D. L.; Wagener, R.

    1990-01-01

    New laboratory observations of the VUV absorption cross-section of C2H2, obtained under physical conditions approximating stratospheres of the giant planets, were combined with IUE observations of the albedo of Saturn, for which improved data reduction techniques have been used, to produce new models for that atmosphere. When the effects of C2H2 absorption are accounted for, additional absorption by other molecules is required. The best-fitting model also includes absorption by PH3, H2O, C2H6 and CH4. A small residual disagreement near 1600 A suggests that an additional trace species may be required to complete the model.

  12. Comparison of ( sup 3 H)Phencyclidine (( sup 3 H)PCP) and ( sup 3 H) N-(1-(2-thienyl) cyclohexyl)piperidine (( sup 3 H)TCP) binding properties to rat and human brain membranes

    SciTech Connect

    Vignon, J.; Chaudieu, I.; Allaoua, H.; Journod, L.; Javoy-Agid, F.; Agid, Y.; Chicheportiche, R.

    1989-01-01

    The investigation of ({sup 3}H)PCP and ({sup 3}H)TCP binding properties to rat cerebrum and cerebellum resulted in the demonstration of multiple binding sites for the two drugs. In the two tissue preparations PCP had a lower affinity than TCP. In membranes from the cerebrum an equal number of high affinity binding sites were present for ({sup 3}H)PCP and ({sup 3}H)TCP. However, low affinity binding sites were two times more numerous for ({sup 3}H)PCP than for ({sup 3}H)TCP. In the cerebellum, the number of high and low affinity sites labeled by the two radioligands was identical, but the number of high affinity sites was about 7 fold lower than in cerebrum. In human cerebral cortex samples ({sup 3}H)TCP also bound to two different sites. The number of high and low affinity sites were 12 and 3 times, respectively, less abundant than in the rat cerebrum. Low affinity sites were of higher affinity than corresponding sites in the rat brain. In the human cerebellum ({sup 3}H)TCP binding parameters were identical to those measured in the same region in the rat.

  13. Synthesis Of [2h, 13c] And [2h3, 13c]Methyl Aryl Sulfides

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

    2004-03-30

    The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2,.sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms. The present invention is also directed to the labeled compounds of [.sup.2 H.sub.1, .sup.13 C]methyl iodide and [.sup.2 H.sub.2, .sup.13 C]methyl iodide.

  14. Fallout /sup 3/H ingestion in Akita, Japan

    SciTech Connect

    Hisamatsu, S.; Takizawa, Y.; Abe, T.; Katsumata, T.

    1987-09-01

    To study fallout /sup 3/H ingestion in Japan, 16 separate food group samples were collected from Akita during 1985. The /sup 3/H concentration in free water and that in a tissue-bound form were determined separately. The average /sup 3/H concentration in the tissue-bound form was 2.2 Bq L-1, 1.7 times higher than in the free water of the food. The ingestions of /sup 3/H in the tissue-bound form and as free water in the diet were 0.60 Bq d-1 and 1.0 Bq d-1, respectively. Cereals represented the food group that contributed the most to the ingestion of tissue-bound /sup 3/H. Total /sup 3/H ingestion was estimated to be 4.1 Bq d-1. The contribution of the tissue-bound form to the total ingestion was 15%, considerably lower than reported for Italian diets. The ratio of /sup 3/H ingestion in the tissue-bound form to the free water form in the diet was similar to the ratio reported for New York City.

  15. Influence of growth pressure on filling 4H-SiC trenches by CVD method

    NASA Astrophysics Data System (ADS)

    Ji, Shiyang; Kojima, Kazutoshi; Kosugi, Ryoji; Saito, Shingo; Sakuma, Yuuki; Tanaka, Yasunori; Yoshida, Sadafumi; Himi, Hiroaki; Okumura, Hajime

    2016-01-01

    To construct a superjunction structure consisting of p/n columns, narrow stripe-shaped trenches (∼1.5 µm wide and ∼4.7 µm deep) preformed on an n+ 4H-SiC substrate were filled by the hot-wall CVD method using a conventional gas reaction system, SiH4:C3H8:H2. The influences of growth pressure on the coverage distribution of epilayers and the corresponding filling efficiency (the thickness ratio of epilayers on trench bottom and mesa top) were investigated. Two benefits of increasing the growth pressure from 10 to 38 kPa were found: one is the reduced growth around the mesa surface, which lessens the risk of void formation; the other is a high filling rate as well as an improved filling efficiency up to ∼7. By supplying source gases at high flow rates, a void-free trench filling with a filling rate of ∼1.3 µm/h was successfully achieved at 38 kPa.

  16. Characterization of phosphorus implantation in 4H-SiC

    SciTech Connect

    Khemka, V.; Patel, R.; Ramungul, N.; Chow, T.P.; Ghezzo, M.; Kretchmer, J.

    1999-03-01

    Silicon carbide is expected to be a promising material for high-voltage semiconductor power devices. The authors report the characterization of phosphorus implantation in 4H-SiC. The implanted layers are characterized by analytical techniques (secondary ion mass spectrometry, transmission electron microscopy) as well as electrical and a sheet resistance value as low as 160 {Omega}/{open_square} has been measured. The authors have also studied the effect of annealing time and temperature on activation of phosphorus implants. It has been shown to be possible to obtain low sheet resistance ({approximately}260 {Omega}/{open_square}) by annealing at a temperature as low as 1,200 C. High-dose ({approximately} 4 {times} 10{sup 15} cm{sup {minus}2}) implants are found to have a higher sheet resistance than that on lower dose implants which is attributed to the near-surface depletion of the dopant during high temperature anneal. Different implantation dosages were utilized for the experiments and subsequently junction rectifiers were fabricated. Forward characteristics of these diodes are observed to obey a generalized Sah-Noyce-Shockly multiple level recombination model with four shallow levels and one deep level.

  17. Photochemical Modeling of the Distribution of C3H8 in the Atmosphere of Saturn

    NASA Astrophysics Data System (ADS)

    Edgington, S. G.; Simon-Miller, A.; Jennings, D.; Bjoraker, G.; Romani, P.; Achterberg, R.; Orton, G.; Flasar, M.; Cassini CIRS Team

    2005-08-01

    Cassini's Composite Infrared Spectrometer (CIRS) has measured the abundance of C2H2 and C3H8 (Propane) at several latitudes in the Southern hemisphere. An increase of radiance with latitude towards the pole has been observed, possibly implying a corresponding increase of C3H8. In an effort explain the observed distribution of both species, it is important to model the creation, destruction, and transport of these chemical species. Furthermore, since both molecules have overlapping absorption features in the same spectral region near 748 cm-1, such modeling will aid in refining derived abundances and separating temperature effects. The photochemistry model used in Edgington et al. (1998, 1999, 2000) to model simultaneously hydrocarbons, ammonia, and phosphine is updated and expanded to include paths relevant to the creation of C3H8. Destruction occurs through photolysis, while transport would tend to spread C3H8 from its source regions. With a series of exercises in 1- and 2- dimensions, we explore the extent to which photolysis, vertical, and/or meridional transport impacts the distribution of C2H2 and C3H8 with latitude. Thermal profiles derived from CIRS observations versus latitude are used as they have an impact on numerous reaction rates. We then compare these results with abundances derived from observations taken with the CIRS instrument. Edgington, S.G., West, R.A., Friedson, A.J., Atreya, S.K., 2000. A 2-D photochemical model with meridional circulation. Bull. American. Astron. Soc., 32, 1013. Edgington, S.G., S.K. Atreya, L.M. Trafton, J.J. Caldwell, R.F. Beebe, A.A. Simon, and R.A. West, 1999. Ammonia and eddy mixing variations in the southern hemisphere of Jupiter from HST Faint Object Spectrograph Observations. Icarus, 142, 342-357. Edgington, S.G., S.K. Atreya, L.M. Trafton, J.J. Caldwell, R.F. Beebe, A.A. Simon, R.A. West, and C. Barnet, 1998. On the latitude variation of ammonia, acetylene, and phosphine altitude profiles on Jupiter from HST Faint

  18. Fallout sup 3 H in human tissue at Akita, Japan

    SciTech Connect

    Hisamatsu, S.; Takizawa, Y.; Itoh, M.; Ueno, K.; Katsumata, T.; Sakanoue, M. )

    1989-10-01

    The {sup 3}H concentration in Japanese human tissue samples is reported in this paper. Four brain, 10 liver, and nine lung samples from 11 cases were collected from Akita Prefecture in northern Japan from January to July 1986. The median of free-water {sup 3}H concentration was similar in these tissues and agreed well with the concentrations in the diet, including tap water. The median specific activity ratio of tissue-bound {sup 3}H to free-water {sup 3}H was 1.1 and was slightly lower than that in the diet. The specific activity ratio was also lower than that reported in the United States and significantly lower than in Italy.

  19. Dissociation of deuterium-defect complexes in ion-implanted epitaxial 4H-SiC

    SciTech Connect

    Janson, M.; Linnarsson, M.K.; Hallen, A.; Svensson, B.G.

    1998-12-31

    Epitaxial layers of low doped 4H-SiC are implanted with 20 keV {sup 2}H{sup +} ions to a dose of 1 {times} 10{sup 15} cm{sup {minus}2}. The samples are subsequently annealed at temperatures ranging from 1040 to 1135 C. Secondary ion mass spectrometry is used to obtain the concentration versus depth profiles of the atomic deuterium in the samples. It is found that the concentration of implanted deuterium decreases rapidly in the samples as a function of anneal time. The experimental data are explained by a model where the deuterium migrates rapidly and becomes trapped and de-trapped at implantation-induced defects which exhibit a slightly shallower depth distribution than the implanted deuterium ions. Computer simulations using this model, in which the damage profile is taken from Monte Carlo simulations and the surface is treated as a perfect sink for the diffusing deuterium atoms, are performed with good results compared to the experimental data. The complexes are tentatively identified as carbon-deuterium at a Si-vacancy and a dissociation energy (E{sub D}) of approximately 4.9 eV is extracted for the deuterium-vacancy complexes.

  20. Stereospecific binding of 3H-phencyclidine in brain membranes.

    PubMed

    Hampton, R Y; Medzihradsky, F; Woods, J H; Dahlstrom, P J

    1982-06-21

    Phencyclidine (PCP) displaceable binding of 3H-PCP to glass-fiber filters was eliminated and total binding markedly reduced by initial treatment of the discs with 0.05% polyethyleneimine. Assessed with treated filters, unlabeled PCP displaced 3H-PCP in both rat and pigeon brain membranes with an EC50 of 1 microM. Of similar high inhibitory potency were dextrorphan, levorphanol, SKF 10047 and ketamine, while morphine, naloxone and etorphine had EC50 values higher then 1 mM. Using the dissociative anesthetic dexoxadrol and its inactive isomer levoxadrol as displacing agents, stereospecific binding of 3H-PCP was obtained in rat and pigeon brain membranes. The markedly higher potency of dexoxadrol, relative to levoxadrol, in displacing bound 3H-PCP is compatible with behavioral data for these enantiomers. However, they were equipotent in displacing 3H-PCP bound to glass-fiber filters in the absence of tissue. Heat denaturation, but not freezing, abolished stereospecific binding of 3H-PCP, which was also absent in rat liver membranes. The stereospecific binding component in brain displayed biphasic saturability at 60-70 nM and 300-400 nM, respectively. PMID:7109842

  1. (/sup 3/H)-beta-endorphin binding in rat brain

    SciTech Connect

    Houghten, R.A.; Johnson, N.; Pasternak, G.W.

    1984-10-01

    The binding of (/sup 3/H)-beta-endorphin to rat brain homogenates is complex. Although Scatchard analysis of saturation studies yields a straight line, detailed competition studies are multiphasic, suggesting that even at low concentrations of the compound, the /sup 3/H-ligand is binding to more than one class of site. A portion of (/sup 3/H)-beta-endorphin binding is sensitive to low concentrations of morphine or D-Ala2-Leu5-enkephalin (less than 5 nM). The inhibition observed with each compound alone (5 nM) is the same as that seen with both together (each at 5 nM). Thus, the binding remaining in the presence of both morphine and the enkephalin does not correspond to either mu or delta sites. The portion of (/sup 3/H)-beta-endorphin binding that is inhibited under these conditions appears to be equally sensitive to both morphine and the enkephalin and may correspond to mu1 sites. Treating membrane homogenates with naloxonazine, a mu1 selective antagonist, lowers (/sup 3/H)-beta-endorphin binding to the same degree as morphine and D-Ala2-Leu5-enkephalin alone or together. This possible binding of (/sup 3/H)-beta-endorphin to mu1 sites is consistent with the role of mu1 sites in beta-endorphin analgesia and catalepsy in vivo.

  2. Uptake of /sup 3/H-choline and synthesis of /sup 3/H-acetylcholine by human penile corpus cavernosum

    SciTech Connect

    Blanco, R.; Saenz de Tejada, I.; Azadzoi, K.; Goldstein, I.; Krane, R.J.; Wotiz, H.H.; Cohen, R.A.

    1986-03-05

    The neuroeffectors which relax penile smooth muscle and lead to erection are unknown; physiological studies of human corpus cavernosum, in vitro, have suggested a significant role of cholinergic neurotransmission. To further characterize the importance of cholinergic nerves, biopsies of human corpus cavernosum were obtained at the time of penile prosthesis implantation. Tissues were incubated in /sup 3/H-choline (10/sup -5/M, 80 Ci/mmol) in oxygenated physiological salt solution at 37/sup 0/C, pH 7.4 for 1 hour. Radiolabelled compounds were extracted with perchloric acid (0.4 M) and acetylcholine and choline were separated by HPLC; /sup 14/C-acetylcholine was used as internal standard. /sup 3/H-choline was accumulated by the tissues (20 +/- 1.9 fmol/mg), and /sup 3/H-acetylcholine was synthesized (4.0 +/- 1.1 fmol/mg). In control experiments, heating of the tissue blocked synthesis of /sup 3/H-acetylcholine. Inhibition of high affinity choline transport by hemicholinium-3 (10/sup -5/M) diminished tissue accumulation of /sup 3/H-choline and significantly reduced the synthesis of /sup 3/H-acetylcholine (0.5 +/ 0.2 fmol/mg, p < 0.05). These results provide direct evidence of neuronal accumulation of choline and enzymatic conversion to acetylcholine in human corpus cavernosum. Taken together with the physiological studies, it can be concluded that cholinergic neurotransmission in human corpus cavernosum plays a role in penile erection.

  3. Spatially Resolved L-C3H+ Emission in the Horsehead Photodissociation Region: Further Evidence for a Top-Down Hydrocarbon Chemistry

    NASA Astrophysics Data System (ADS)

    Guzmán, V. V.; Pety, J.; Goicoechea, J. R.; Gerin, M.; Roueff, E.; Gratier, P.; Öberg, K. I.

    2015-02-01

    Small hydrocarbons, such as C2H, C3H, and C3H2 are more abundant in photo-dissociation regions (PDRs) than expected based on gas-phase chemical models. To explore the hydrocarbon chemistry further, we observed a key intermediate species, the hydrocarbon ion l-C3H+, in the Horsehead PDR with the Plateau de Bure Interferometer at high-angular resolution (6″). We compare with previous observations of C2H and c-C3H2 at similar angular resolution and new gas-phase chemical model predictions to constrain the dominant formation mechanisms of small hydrocarbons in low-UV flux PDRs. We find that at the peak of the HCO emission (PDR position), the measured l-C3H+, C2H, and c-C3H2 abundances are consistent with current gas-phase model predictions. However, in the first PDR layers, at the 7.7 μm polycyclic aromatic hydrocarbon band emission peak, which are more exposed to the radiation field and where the density is lower, the C2H and c-C3H2 abundances are underestimated by an order of magnitude. At this position, the l-C3H+ abundance is also underpredicted by the model but only by a factor of a few. In addition, contrary to the model predictions, l-C3H+ peaks further out in the PDR than the other hydrocarbons, C2H and c-C3H2. This cannot be explained by an excitation effect. Current gas-phase photochemical models thus cannot explain the observed abundances of hydrocarbons, in particular, in the first PDR layers. Our observations are consistent with a top-down hydrocarbon chemistry, in which large polyatomic molecules or small carbonaceous grains are photo-destroyed into smaller hydrocarbon molecules/precursors. Based on observations obtained with the IRAM Plateau de Bure interferometer and 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).

  4. 7 CFR 8.9 - Use in 4-H fund raising.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Use in 4-H fund raising. 8.9 Section 8.9 Agriculture Office of the Secretary of Agriculture 4-H CLUB NAME AND EMBLEM § 8.9 Use in 4-H fund raising. (a) Fund-raising programs using the 4-H Name or Emblem may be carried out for specific educational purposes. Such fund-raising programs and use of the...

  5. SADDLE HORSE AND OTHER LIVESTOCK ADVISORS' PERCEPTIONS OF 4-H CLUB WORK IN OHIO.

    ERIC Educational Resources Information Center

    GROVES, ROBERT H.

    PERCEPTIONS AND UNDERSTANDINGS OF 4-H OBJECTIVES AND PROGRAMS OF 4-H SADDLE HORSE ADVISORS WERE COMPARED WITH THOSE OF OTHER LIVESTOCK ADVISORS IN NORTHEASTERN AND SOUTHWESTERN DISTRICTS OF OHIO. DATA WERE COLLECTED BY QUESTIONNAIRES FROM 90 SADDLE HORSE AND 133 OTHER LIVESTOCK ADVISORS. STATE 4-H STAFF AND SUPERVISORS PROVIDED CORRECT ANSWERS.…

  6. Using the Delphi Technique to Assess Educational Needs Related to Extension's 4-H Beef Program.

    ERIC Educational Resources Information Center

    Shih, Ching-Chun; Gamon, Julia A.

    1997-01-01

    Delphi panels completing questionnaires included 32 parents of 4-H students, 16 extension beef specialists, 21 4-H field specialists, and 21 industry representatives. They identified 31 subject-matter and 30 life-skill topics useful for 4-H manuals. Emerging topics included consumer and environmental concerns. (SK)

  7. Perceptions of Missouri 4-H Youth Development Personnel Regarding Interorganizational Cooperative Behavior

    ERIC Educational Resources Information Center

    McKim, Billy R.; Torres, Robert M.

    2011-01-01

    Perceptions of 4-H youth development personnel regarding interorganizational cooperation were studied between the perceived and desired levels of cooperative activities between 4-H youth development personnel and secondary agriculture teachers. Results indicated that 4-H youth development personnel wanted higher levels of coordinated efforts…

  8. Examination of Attitude and Interest Measures for 4-H Science Evaluation

    ERIC Educational Resources Information Center

    Lewis, Kendra M.; Worker, Steven M.

    2015-01-01

    Science education research has demonstrated the influence of affect on learning. The National 4-H Science Logic Model outlines outcomes from youth participation in 4-H science programs, which includes attitude and interest outcomes. The associated measure, the National 4-H Science Common Measure, assesses these attitude constructs and not other…

  9. Perceptions of Texas 4-H Livestock Ambassadors on Career Development, Higher Education, and Leadership Development

    ERIC Educational Resources Information Center

    Zanolini, William F.; Rayfield, John; Ripley, Jeff

    2013-01-01

    Selected 4-H youth participated in the Texas 4-H Livestock Ambassador program. Forty-five youth participated in the 3-day program delivered by university professors and staff, Texas AgriLife Extension faculty and industry representatives. An instrument was developed and administered to the Texas 4-H Livestock Ambassadors at the end of their first…

  10. Understanding the Knowledge and Use of Experiential Learning within Pennsylvania 4-H Clubs

    ERIC Educational Resources Information Center

    Bechtel, Robyn; Ewing, John C.; Threeton, Mark; Mincemoyer, Claudia

    2013-01-01

    Experiential learning is incorporated into the National 4-H curriculum. However, the state 4-H staff in Pennsylvania is unsure of the current knowledge and use of experiential learning within the local 4-H clubs. An online survey was distributed to Extension educators and volunteer leaders within Pennsylvania to assess the current knowledge and…

  11. Relationship between Participation in 4-H and Community Leadership in Rural Montana

    ERIC Educational Resources Information Center

    Flynn, Allison; Frick, Martin; Steele, Douglas

    2010-01-01

    Studies on the impact of 4-H on former members generally use alumni as one cohort. In rural states, such as Montana, it is important to understand the impact of 4-H on alumni in these rural areas and the role 4-H plays in community involvement. The study reported here sought to determine the perception of current community leaders in rural Montana…

  12. Expression analysis of kenaf cinnamate 4-hydroxylase (C4H) ortholog during developmental and stress responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to clone and analyze the expression pattern of a C4H gene encoding cinnamate 4-hydroxylase from kenaf (Hibiscus cannabinus L.). A full-length C4H ortholog was cloned using degenerate primers and the RACE (rapid amplification of cDNA ends) method. The full-length C4H ortholog...

  13. Text to Speech: A 4-H Model of Accessibility and Inclusion

    ERIC Educational Resources Information Center

    Green, Jeremy W.

    2012-01-01

    4-H project manuals play an integral part in a youth's ability to achieve mastery in a specific project area. For youth who struggle with reading, written 4-H materials prove inadequate in addressing the needs of the learner. This article proposes a new delivery method of 4-H educational material designed to create a more inclusive and…

  14. Stewardship as a Means to Create Organizational Reform: A View into Minnesota 4-H Youth Development

    ERIC Educational Resources Information Center

    Skuza, Jennifer A.; Freeman, Dorothy M.; Bremseth, Tamara J.; Doering, Shirley A.; Quinlan, Robert B.; Morreim, Patricia A.; Deidrick, James C.

    2010-01-01

    Minnesota 4-H Youth Development (MN 4-H) used stewardship as a means to create organizational reform to address the public use of the 4-H name and emblem in terms of risk management, real estate and equipment, and finances. A task force implemented a participatory process with colleagues and stakeholders to build and implement the reform effort.…

  15. Density functional studies on the endohedral complex of fullerene C70 with tetrahedrane (C4H4): C4H4@C70.

    PubMed

    Ren, Xiao-Yuan; Jiang, Cai-Ying

    2012-07-01

    B3LYP/6-31G(d) hybrid HF/DFT calculations were carried out to determine the structural and electronic properties of the endohedral complex of a C(70) cage with tetrahedrane (C(4)H(4)). It was demonstrated that the formation of the complex is endothermic, with a destabilization energy of 72.56 kcal mol(-1). C(4)H(4) is seated in the center of the C(70) cage and exists in molecular form inside the fullerene. C(4)H(4) endohedral doping slightly perturbs the molecular orbitals of C(70). The calculated HOMO-LUMO gaps, the electron affinity (EA), and the ionization potential (IP) indicate that C(4)H(4)@C(70) is more chemically reactive than C(70). The IR active modes and harmonic vibrational frequencies of C(4)H(4)@ C(70) are also discussed. PMID:22246288

  16. Pharmacological studies on quaternized 4(3H)-quinazolinones.

    PubMed

    Buyuktimkin, S; Ekinci, A C; Buyuktimkin, N; Otuk, G

    1992-11-01

    Locomotor activity-inhibiting, anticonvulsant, muscle relaxant, analgesic, and antimicrobial properties of 2-methyl-3-pyridinium-acetylamino-4(3H)-quinazolinone chloride (1), 2-methyl-3-(4-methylpyridinium)acetylamino-4(3H)-quinazolinone chloride (2), 2-methyl-3-(4-ethylpyridinium)acetylamino-4(3H)-quinazolinone chloride (3), 2-methyl-3-(3-carboxamidopyridinium)acetylamino-4(3H)-quinazolinon e chloride (4), and 2-methyl-3-(4-carboxamidopyridinium)-acetylamino-4(3H)- quinazolinone chloride (5) were investigated. The locomotor activity-inhibiting properties and anticonvulsant activity of 2 were almost equal to those of methaqualone. The analgesic activities of 2 and 3 in the hot-plate test were equal to that of aspirin, whereas in the Koster test, the analgesic activity of 2 was higher. The compounds did not exhibit antimicrobial or muscle relaxant properties. Most active compounds had higher lipophilicity values than those of inactive compounds. PMID:1447711

  17. Melting of H_2SO_4\\cdot4H_2O Particles upon Cooling: Implications for Polar Stratospheric Clouds

    NASA Astrophysics Data System (ADS)

    Koop, Thomas; Carslaw, Kenneth S.

    1996-06-01

    Polar stratospheric clouds (PSCs) are important for the chemical activation of chlorine compounds and subsequent ozone depletion. Solid PSCs can form on sulfuric acid tetrahydrate (SAT) (H_2SO_4\\cdot4H_2O) nuclei, but recent laboratory experiments have shown that PSC nucleation on SAT is strongly hindered. A PSC formation mechanism is proposed in which SAT particles melt upon cooling in the presence of HNO_3 to form liquid HNO_3-H_2SO_4\\cdotH_2O droplets 2 to 3 kelvin above the ice frost point. This mechanism offers a PSC formation temperature that is defined by the ambient conditions and sets a temperature limit below which PSCs should form.

  18. Thermal Dehydrogenation of Base-Stabilized B2H5(+) Complexes and Its Role in C-H Borylation.

    PubMed

    Prokofjevs, Aleksandrs

    2015-11-01

    Thermally induced dehydrogenation of the H-bridged cation L2B2H5(+) (L=Lewis base) is proposed to be the key step in the intramolecular C-H borylation of tertiary amine boranes activated with catalytic amounts of strong "hydridophiles". Loss of H2 from L2B2H5(+) generates the highly reactive cation L2B2H3(+), which in its sp(2)-sp(3) diborane(4) form then undergoes either an intramolecular C-H insertion with B-B bond cleavage, or captures BH3 to produce L2B3H6(+). The effect of the counterion stability on the outcome of the reaction is illustrated by formation of LBH2C6F5 complexes through disproportionation of L2B2H5(+) HB(C6F5)3(-) . PMID:26377358

  19. Monoamine oxidase inhibitory activity of 2-aryl-4H-chromen-4-ones.

    PubMed

    Nayak, Badavath Vishnu; Ciftci-Yabanoglu, S; Bhakat, Soumendranath; Timiri, Ajay Kumar; Sinha, Barij N; Ucar, G; Soliman, Mahmoud E S; Jayaprakash, Venkatesan

    2015-02-01

    A series of twenty 2-aryl-4H-chromen-4-one (flavones) derivatives (3a-3s) were synthesized and tested for hMAO inhibitory activity. Fifteen compounds (3a, 3c, 3e-3h, 3j-3p, 3r, 3s) were found to be selective towards MAO-B, while 3d was selective towards MAO-A, and 3b, 3i and 3q were non-selective. Experimental Selectivity Index for MAO-B ranges from 2.0 (3g, 3p) to 30.0 (3j). Compound 3j, which is carrying 3,4-di-OMeC6H3 groups at R position on the molecule, was found to be potent MAO-B inhibitor amongst the fifteen with Ki value for MAO-B of 0.16±0.01 μM comparable to that of standard drug, Selegiline (Ki for MAO-B is 0.16±0.01 μM). Compound 3j also appeared as the most selective MAO-B inhibitor according to its best selectivity index (30.0), which is comparable to that of Selegiline (SIMAO-B=35.0). Molecular docking and molecular dynamics simulation studies were carried out using Autodock-4.0 and Amber12 to understand the molecular level interaction and energy relation of MAO isoforms with selective inhibitors (3d and 3j). Simulation results are in good agreement with the experimental results. Leads identified may further be explored to develop potent isoform specific inhibitors of MAO. PMID:25506816

  20. Homocatenation of aluminum: alkane-like structures of Li2Al2 H6 and Li3Al3H8.

    PubMed

    Gish, J Tyler; Popov, Ivan A; Boldyrev, Alexander I

    2015-03-27

    Invited for the cover of this issue is Alexander I. Boldyrev and co-workers at Utah State University. The image depicts the magician who symbolizes a chemist synthesizing molecules of "aluminum homocatenated ethane and propane" based on the idea of electronic transmutation. Read the full text of the article at 10.1002/chem.201500298. PMID:25736330

  1. Oxidative coupling between C(sp(2))-H and C(sp(3))-H bonds of indoles and cyclic ethers/cycloalkanes.

    PubMed

    Yang, Qingjing; Choy, Pui Ying; Wu, Yinuo; Fan, Baomin; Kwong, Fuk Yee

    2016-02-24

    Cross-dehydrogenative-coupling (CDC) between C-H/C-H bonds of indoles and cyclic ethers/cycloalkanes is made viable through a simple transition-metal-free pathway. With the aid of only di-tert-butyl peroxide, a number of inactive cyclic ethers and cycloalkanes can be directly coupled with indole derivatives in satisfactory yields. PMID:26842403

  2. Water-Isotopes (2H, 3H, 18O) to trace the source and timing of recharge in a fractured granite aquifer in Western Kenya, Africa

    NASA Astrophysics Data System (ADS)

    Kralik, Martin; Whylidal, Stefan; Asunah, Francis; Sültenfuß, Jürgen

    2014-05-01

    The Vihiga District in West Kenya North-West of Lake Victoria is one of the most densely populated areas in Kenya with 1033 person per square kilometer. To find the most suitable location of an own well for a Primary School in this district, springs, school wells and creeks were sampled in the surroundings to get information about the hydrological cycle in the area. The Waluka Primary school (0.02134°N, 34.64311°E) is situated on the northern slope of the Maragoli Hills 20 km to the North-West of the Nyanzan provincial capital of Kisumu at the eastern shore of Lake Victoria. The hilly relief varies between 1535 - 1675m. The yearly precipitation is between 1200-1600 mm/a (23°C mean temperature) with biannual rainy seasons in which the long rains are generally from March to May as the Inter-Tropical Convergence Zone (ITCZ) moves northwards, and the short rains are typically from October to December as the ITCZ retreats southwards. A lateritic soil covers a thin alteration zone above the Precambrian Maragoli-Granite (Saggerson, 1952). Water circulates either in the thin alteration zone or in fault zones cutting through the Precambrian granite. From discharge measurements of two springs and a creek at the end of the dry season (February 2012) a minimum discharge of ca. 10-20 L/s km2 (300-600 mm) can be estimated. The water is of the alkaline sulfate-nitrate type with low mineralization (70-150 μ S/cm, 25°C) and a low pH of about 5 to 6. The delta oxygen-18 and deuterium value ranges between -2.84 to -1.98 oand -8.5 to - 3.9 o(VSMOW). The deuterium excess ranges from 11.7-14.2 oThe water of one spring and well close to the school have a tritium content of 1.42 - 1.62 TU. All groundwater has a low arsenium, fluorine and uranium content, which had only a short soil passage. The relatively elevated, but not problematic content in nitrate (10 - 16 mg/L) probaly reflects the intensive agricultural activities in this area. As the mean δ 18O values during the rainy seasons are significantly lower (-3 to -4 o) than in the mean precipitation during the rest of the year (-2.5 to -1.9 o; Mwango, 2003) one can conclude that the main spring 'Anzaya' and the well in the Naboka Secondary School are recharged from deeper faults with water supplied more during the rainy season. The slightly higher d-excess of 13.4-14.2 ocompared to 11.7-12.6 oin the rest of the samples, indicates a somewhat higher recharge area of this two sites with water vapor recycled in the precipitation around the Liailhunuu peak (ca. 1675m). This effect is also supported by spring-water measurements at the Kilimanjaro (d-excess 13.4-6.6 o) 400 km SE. Similarily, the tritium content of 1.42 - 1.62 TU indicate that compared to a mean tritium content of 2 TU in the rain of this area (Mwango, 2003) the mean residence time can be in the range of recent to few years only.

  3. Cross-dehydrogenative coupling of α-C(sp(3))-H of ethers/alkanes with C(sp(2))-H of heteroarenes under metal-free conditions.

    PubMed

    Ambala, Srinivas; Thatikonda, Thanusha; Sharma, Shweta; Munagala, Gurunadham; Yempalla, Kushalava Reddy; Vishwakarma, Ram A; Singh, Parvinder Pal

    2015-12-14

    Here we have developed an effective metal-free dehydrogenative coupling method wherein α-oxyalkyl and alkyl radicals were generated from various ethers and alkanes to undergo coupling with a variety of electron-deficient heteroarenes such as un/substituted iso-quinolones, quinolines, pyridines, pyrazines and pyrimidines. The persulfate-acetone-water system was optimized for the dehydrogenative coupling with cyclic ethers which gave moderate to excellent yields of α-oxyalkyl containing heteroarenes. We have also optimized the conditions for coupling with cyclic alkanes and alicyclic ethers and demonstrated by conducting the reactions with a variety of electron-deficient heteroarenes. Further, the present method is also applicable to electron deficient arenes like naphthoquinones and moreover, it didn't require any external acid. PMID:26419479

  4. R-matrix description of particle energy spectra produced by low-energy 3H + 3H reactions

    DOE PAGESBeta

    Brune, C. R.; Caggiano, J. A.; Sayre, D. B.; Bacher, A. D.; Hale, G. M.; Paris, M. W.

    2015-07-20

    An R-matrix model for three-body final states is presented and applied to a recent measurement of the neutron energy spectrum from the 3H + 3H→ 2n + α reaction. The calculation includes the n alpha and n n interactions in the final state, angular momentum conservation, antisymmetrization, and the interference between different channels. A good fit to the measured spectrum is obtained, where clear evidence for the 5He ground state is observed. The model is also used to predict the alpha-particle spectrum from 3H + 3H as well as particle spectra from 3He + 3He. The R-matrix approach presented heremore » is very general, and can be adapted to a wide variety of problems with three-body final states.« less

  5. Partial phase diagram for the system NH3-H2O - The water-rich region

    NASA Technical Reports Server (NTRS)

    Johnson, M. L.; Schwake, A.; Nicol, M.

    1984-01-01

    Phase boundaries of the H2O-NH3 system for (NH3)/x/(H2O)/1-x/ have been determined with diamond-anvil cells for mixtures in two composition ranges: (1) for x in the range from 0 to 0.3, at pressures up to 4 GPa at 21 C, and (2) for x in the range from 0.46 to 0.50, at pressures up to 5 GPa from 150 to 400 K. Phases were identified visually with a microscope and polarized optics. The NH3.2(H2O) phase is strongly anisotropic with a much smaller refractive index than that of ice VII and cracks in two nonperpendicular networks. NH3.H2O has a refractive index closer to that of Ice VII and does not appear to form cracks. Both phases are colorless. Phase boundaries were determined on both increasing and decreasing pressures, and compositions of the ammonia ices were determined by estimating relative amounts of water and ammonia ices at known overall compositions. For low-ammonia compositions (x equal to or less than 0.15), the following assemblages succedd one another as pressure increases: liquid; liquid and Ice VI (at 1.0 + GPa); liquid and Ice VII (at 2.1 GPa); Ice VII and NH3.H2O (at 3.5 GPa). For x in the range from 0.15 to 0.30, the water ice and liquid fields are replaced by the NH3.2(H2O) and liquid field at pressures down to 1.0 GPa and lower.

  6. Complex Hydrocarbon Chemistry in Interstellar and Solar System Ices Revealed: A Combined Infrared Spectroscopy and Reflectron Time-of-flight Mass Spectrometry Analysis of Ethane (C2H6) and D6-Ethane (C2D6) Ices Exposed to Ionizing Radiation

    NASA Astrophysics Data System (ADS)

    Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-08-01

    The irradiation of pure ethane (C2H6/C2D6) ices at 5.5 K, under ultrahigh vacuum conditions was conducted to investigate the formation of complex hydrocarbons via interaction with energetic electrons simulating the secondary electrons produced in the track of galactic cosmic rays. The chemical modifications of the ices were monitored in situ using Fourier transform infrared spectroscopy (FTIR) and during temperature-programmed desorption via mass spectrometry exploiting a quadrupole mass spectrometer with electron impact ionization (EI-QMS) as well as a reflectron time-of-flight mass spectrometer coupled to a photoionization source (PI-ReTOF-MS). FTIR confirmed previous ethane studies by detecting six molecules: methane (CH4), acetylene (C2H2), ethylene (C2H4), the ethyl radical (C2H5), 1-butene (C4H8), and n-butane (C4H10). However, the TPD phase, along with EI-QMS, and most importantly, PI-ReTOF-MS, revealed the formation of at least 23 hydrocarbons, many for the first time in ethane ice, which can be arranged in four groups with an increasing carbon-to-hydrogen ratio: C n H2n+2 (n = 3, 4, 6, 8, 10), C n H2n (n = 3–10), {{{C}}}n{{{H}}}2n-2 (n = 3–10), and {{{C}}}n{{{H}}}2n-4 (n = 4–6). The processing of simple ethane ices is relevant to the hydrocarbon chemistry in the interstellar medium, as ethane has been shown to be a major product of methane, as well as in the outer solar system. These data reveal that the processing of ethane ices can synthesize several key hydrocarbons such as C3H4 and C4H6 isomers, which ha­ve been found to synthesize polycyclic aromatic hydrocarbons like indene (C9H8) and naphtha­lene (C10H8) in the ISM and in hydrocarbon-rich atmospheres of planets and their moons such as Titan.

  7. The reinvestigation of the kinetics of the metathesis reactions t-C4H9• + HBr (HI) → i-C4H10 + Br• (I•) and of the t-C4H9• free radical thermochemistry.

    PubMed

    Leplat, N; Rossi, M J

    2014-07-17

    A reinvestigation of the absolute rate constant of the metathesis reactions t-C4H9• + HBr → i-C4H10 + Br• (1) and t-C4H9• + HI → i-C4H10 + I• (2) was performed thanks to a recently developed apparatus consisting of a Knudsen reactor coupled to detection based on single-photon (VUV) photoionization mass spectrometry (SPIMS). It enables the generation of thermalized hydrocarbon free radicals owing to a source upstream of and external to the Knudsen reactor. The following Arrhenius expressions were obtained: k1 = 5.6(±1.4) × 10(–12) exp(−6.76(±0.94)/(RT)) and k2 = 2.0(±0.6) × 10(–11) exp(−8.48(±0.94)/(RT)) with R = 8.314 J mol(–1) K(–1) over the range 293 to 623 K. The mass balance of the reaction system based on closed shell product detection (CSPD) was checked in order to ensure the accuracy of the used reaction mechanism and as an independent check of k1 and k2. The wall-loss rate constants of the t-butyl free radical, kw(C4H9), were measured and found to be low compared with the corresponding escape rate constant, ke(C4H9), for effusion of t-C4H9• out of the Knudsen reactor. On the basis of the present results, the free radical standard heat of formation ΔfH298°(t-C4H9•) = 44.3 ± 1.7 kJ mol(–1) was obtained when combined with the kinetics of the inverse halogenation reaction taken from the literature and using S298°(t-C4H9•) = 322.2 J K(–1) mol(–1) following a “Third Law” evaluation method. The standard enthalpy for t-butyl free radical is consistent for both the bromination and iodination reactions within the stated uncertainties. PMID:24942181

  8. Synthesis and β-glucuronidase inhibitory activity of 2-arylquinazolin-4(3H)-ones.

    PubMed

    Khan, Khalid Mohammed; Saad, Syed Muhammad; Shaikh, Nimra Naveed; Hussain, Shafqat; Fakhri, Muhammad Imran; Perveen, Shahnaz; Taha, Muhammad; Choudhary, Muhammad Iqbal

    2014-07-01

    2-Arylquinazolin-4(3H)-ones 1-25 were synthesized by reacting anthranilamide with various benzaldehydes using CuCl2·2H2O as a catalyst in ethanol under reflux. Synthetic 2-arylquinazolin-4(3H)-ones 1-25 were evaluated for their β-glucuronidase inhibitory potential. A trend of inhibition IC50 against the enzyme in the range of 0.6-198.2μM, was observed and compared with the standard d-saccharic acid 1,4-lactone (IC50=45.75±2.16μM). Compounds 13, 19, 4, 12, 14, 22, 23, 25, 15, 8, 17, 11, 21, 1, 3, 18, 9, 2, and 24 with the IC50 values within the range of 0.6-44.0μM, indicated that the compounds have superior activity than the standard. The compounds showed no cytotoxic effects against PC-3 cells. A structure-activity relationship is established. PMID:24844756

  9. H3(+) + H2 isotopic system at low temperatures: microcanonical model and experimental study.

    PubMed

    Hugo, Edouard; Asvany, Oskar; Schlemmer, Stephan

    2009-04-28

    State-to-state thermal rate coefficients for reactions of all H(3)(+) + H(2) isotopic variants are derived and compared to new experimental data. The theoretical data are also sought for astrochemical modeling of cold environments (<50 K). The rates are calculated on the basis of a microcanonical approach using the Langevin model and the conservation laws of mass, energy, angular momentum, and nuclear spin. Full scrambling of all five nuclei during the collision is assumed for the calculations and alternatively partial dynamical restrictions are considered. The ergodic principle of the collision is employed in two limiting cases, neglecting (weak ergodic limit) or accounting for explicit degeneracies of the reaction mechanisms (strong ergodic limit). The resulting sets of rate coefficients are shown to be consistent with the detailed balance and thermodynamical equilibrium constants. Rate coefficients, k(T), for the deuteration chain of H(3)(+) with HD as well as H(2)D(+)/H(3)(+) equilibrium ratios have been measured in a variable temperature 22-pole ion trap. In particular, the D(2)H(+) + HD --> D(3)(+) + H(2) rate coefficient indicates a change in reaction mechanism when going to higher temperatures. The good overall agreement between experiment and theory encourages the use of the theoretical predictions for astrophysical modeling. PMID:19405574

  10. Synthesis, Antiviral and Cytotoxic Activities of 2-(2-Phenyl carboxylic acid)-3-Phenylquinazolin -4(3H)-one Derivatives

    PubMed Central

    Selvam, P.; Murugesh, N.; Chandramohan, M.; Pannecouque, C.; DE Clercq, E.

    2010-01-01

    A series of novel 2,3-disubstitutedquinazolin-4(3H)-ones have been synthesized by condensation of 2-substituted benzo[1,3]oxazine-4-ones and anthranilic acid. Synthesized compounds were evaluated for in vitro antiviral activity against HIV, HSV and vaccinia viruses. 5-Bromo-2-(6-bromo-4-oxo-2-phenyl-4H-quinazolin-3-yl)-benzoic acid (MBR2) exhibited distinct antiviral activity against Herpes simplex and vaccinia viruses. PMID:21969760

  11. Laeve-[1-3H]Methadone disposition in tolerant dogs.

    PubMed

    Misra, A L; Bloch, R; Vadlamani, N L; Mulé, S J

    1975-04-01

    1. Following a subcutaneous dose (4mg/kg) of [3H]methadone, peak levels of drug occurred in plasma, tissues and selected areas of the central nervous system (CNS) 2h after injection in both non-tolerant and tolerant dogs. Highest concentrations of methadone were attained in bile and lung compared to other tissues. 2. Levels of methadone in plasma, tissue and CNS of tolerant and non-tolerant animals were not markedly different up to 8h after injection, but a much faster rate of egression of free drug (lower t1/2) was observed subsequently in tolerant dogs. 3. Peak levels of methadone in various areas of the CNS ranged between 2-7 (spinal cord) to 3-6 (thalamus) mug/g in non-tolerant and 3-0 -rebellum) to 4-1 (thalamus) mug/g in tolerant dogs 2h after injection. No marked accumulation of methadone occurred in selected areas of the CNS in spite of the persistence of drug in these areas. 4. The plasma protein electrophoretic profiles did not differ between control, non-tolerant and tolerant dogs. 5. Similar qualitative patterns of metabolites were observed in non-tolerant and tolerant dogs and the development of tolerance did not appear to modify the metabolic pathways of methadone. PMID:1154803

  12. Rate Coefficients of C2H with C2H4, C2H6, and H2 from 150 to 359 K

    NASA Technical Reports Server (NTRS)

    Opansky, Brian J.; Leone, Stephen R.

    1996-01-01

    Rate coefficients for the reactions C2H with C2H4, C2H6, and H2 are measured over the temperature range 150-359 K using transient infrared laser absorption spectroscopy. The ethynyl radical is formed by photolysis of C2H2 with a pulsed excimer laser at 193 nm, and its transient absorption is monitored with a color center laser on the Q(sub 11)(9) line of the A(sup 2) Pi-Chi(sup 2) Sigma transition at 3593.68 cm(exp -1). Over the experimental temperature range 150-359 K the rate constants of C2H with C2H4, C2H6, and H2 can be fitted to the Arrhenius expressions k(sub C2H4) = (7.8 +/- 0.6) x 10(exp -11) exp[(134 +/- 44)/T], k(sub C2H6) = (3.5 +/- 0.3) x 10(exp -11) exp[(2.9 +/- 16)/T], and k(sub H2) = (1.2 +/- 0.3) x 10(exp -11) exp[(-998 +/- 57)]/T cm(exp 3) molecule(exp -1) sec(exp -1). The data for C2H with C2H4 and C2H6 indicate a negligible activation energy to product formation shown by the mild negative temperature dependence of both reactions. When the H2 data are plotted together with the most recent high-temperature results from 295 to 854 K, a slight curvature is observed. The H2 data can be fit to the non-Arrhenius form k(sub H2) = 9.2 x 10(exp -18) T(sup 2.17 +/- 0.50) exp[(-478 +/- 165)/T] cm(exp 3) molecules(exp -1) sec(exp -1). The curvature in the Arrhenius plot is discussed in terms of both quantum mechanical tunneling of the H atom from H2 to the C2H radical and bending mode contributions to the partition function.

  13. 4-H PetPALS Juvenile Diversion Program Supports At-Risk Youth and Seniors

    ERIC Educational Resources Information Center

    Goble, Connie L.; Miller, Lucinda B.

    2014-01-01

    The 4-H PetPALS Juvenile Diversion Program provides a partnership opportunity with Extension and the juvenile court system to positively impact lives of at-risk youth. At-risk youth are taught by 4-H PetPALS adult volunteer leaders and 4-H PetPALS members to value and respect the human-animal bond, as well as to understand and empathize with…

  14. Quantitation of methadone enantiomers in humans using stable isotope-labeled (2H3)-, (2H5)-, and (2H8)Methadone

    SciTech Connect

    Nakamura, K.; Hachey, D.L.; Kreek, M.J.; Irving, C.S.; Klein, P.D.

    1982-01-01

    A new technique for simultaneous stereoselective kinetic studies of methadone enantiomers was developed using three deuterium-labeled forms of methadone and GLC-chemical-ionization mass spectrometry. A racemic mixture (1:1) of (R)-(-)-(2H5)methadone (l-form) and (S)-(R)-(2H3)methadone (d-form) was administered orally in place of a single daily dose of unlabeled (+/-)-(2H0)methadone in long-term maintenance patients. Racemic (+/-)-(2H8)methadone was used as an internal standard for the simultaneous quantitation of (2H0)-, (2H3)-, and (2H5)methadone in plasma and urine. A newly developed extraction procedure, using a short, disposable C18 reversed-phase cartridge and improved chemical-ionization procedures employing ammonia gas, resulted in significant reduction of the background impurities contributing to the ions used for isotopic abundance measurements. These improvements enabled the measurement of labeled plasma methadone levels for 120 hr following a single dose. This methodology was applied to the study of methadone kinetics in two patients; in both patients, the analgesically active l-enantiomer of the drug had a longer plasma elimination half-life and a smaller area under the plasma disappearance curve than did the inactive d-form.

  15. Adiabatic hyperspherical study of weakly bound He(2)H(-), He(2)H, and HeH(2) systems.

    PubMed

    Suno, Hiroya

    2010-06-14

    The He(2)H(-), He(2)H, and HeH(2) triatomic systems are studied using the adiabatic hyperspherical representation. By adopting the best empirical interaction potentials, we search for weakly bound states of (4)He(2) H(-), (4)He(2) H, and (4)HeH(2). We consider not only zero total nuclear orbital angular momentum, J=0, states but also J>0 states. We find no bound state for the (4)He(2) H systems, while the (4)He(2) H(-) and (4)HeH(2) systems are shown to possess three and one bound states, respectively, for J(Pi)=0(+). Interestingly, one bound state has been found each for the J(Pi)=1(-) and 2(+) symmetries of the (4)He(2) H(-) anion. We shall calculate the bound state energies and analyze the molecular structure of these species in detail. PMID:20550401

  16. Preformance Analysis of NH3-H2O Absorption Cycle

    NASA Astrophysics Data System (ADS)

    Tsujimori, Atsushi; Ozaki, Eiichi

    Different from H2O-LiBr absorption cycle, it is necessary to have rectifier between generator and condenser in NH3-H2O absorption cycle, because there mixes some steam in refrigerant vapor in the process of regenerating refrigerant from the ammonia strong aqueous solution. And in some case ex. partial load or heating, the efficiency of rectifier might decrease, if the flow rate of refrigerant vapor and ammonia aqueous solution decrease. As a result, steam flow into condenser with ammonia refrigerant vapor, which reduces cycle COPs of cooling and heating. Accordingly in order to evaluate the effect of ammonia concentration in refrigerant for the performance of NH3-H2O absorption heat pump, the simple design approach of modeling condenser and evaporator is introduced in this paper. In the model, the calculation of heat rate in condenser and evaporator was simplified considering the characteristic of NH3-H2O liquid-vapor equilibrium. Then the simulation for cycle perforance based on GAX absorption cycle was made using the efficiency of rectifier that established the ammonia concentration in refrigerant and it was derived that 3 [%] decrease of ammonia concentration in refrigerant induced 15 [%] decrcase of cooling COP and 7 [%] decrease of heating COP and that there existed the most suitable circulation ratio for each ammonia concentration in refrigerant.

  17. (/sup 3/H)nitrendipine binding to adrenal capsular membranes

    SciTech Connect

    Finkel, M.S.; Aguilera, G.; Catt, K.J.; Keiser, H.R.

    1984-08-20

    The physiologic regulation of aldosterone secretion is dependent on extracellular calcium and appears to be mediated by increases in cytosolic free calcium concentration in the zona glomerulosa cell. A specific role for voltage-dependent calcium channels was suggested by previous studies with the calcium channel antagonist verapamil. The authors therefore studied the (/sup 3/H)nitrendipine calcium channel binding site in adrenal capsules. These studies revealed a single class of saturable, high affinity sites with K/sub D/ = .26 +/- .04 nM and B/sub max/ = 105 +/- 5.7 fmol/mg protein. Specific binding of (/sup 3/H)nitrendipine was inhibited by calcium channel antagonists with potencies nitrendipine = nifedipine >> verapamil, while diltiazem had no inhibitory effect. In the rat, binding sites for (/sup 3/H)nitrendipine were located in the adrenal capsule and medulla and were undetectable in the zona fasciculata. Physiologic studies with collagenase-dispersed adrenal glomerulosa cells demonstrated that nifedipine selectively inhibited angiotensin-II and potassium-stimulated steroidogenesis. These observations suggest both a pharmacologic and physiologic role for the nitrendipine binding site in aldosterone production. 17 references, 2 figures, 1 table.

  18. Removal of arsenic from effluents - a comparison between the FeSO{sub 4}/Air and FeSO{sub 4}/H{sub 2}O{sub 2} systems

    SciTech Connect

    Teixeira, L.A.; Kohler, H.M. |; Kohler, H.M.; Monteiro, A.G.

    1996-12-31

    This paper reports the results of kinetic studies involving the precipitation of arsenic from aqueous solutions as FeAsO{sub 4} / Fe(OH){sub 3}, using FeSO{sub 4} as source of Fe ions, and Air or H{sub 2}O{sub 2} as oxidizing agents. Both systems lead to an efficient removal of arsenic. The differences in oxidants performances are in the precipitation reaction rate - much faster using hydrogen peroxide. Mechanisms of reactions were suggested based on the following main steps: Fe(II) oxidation: 2 Fe{sup 2+} + 1/2 O{sub 2} + 2 H{sup +} 2 Fe{sup 3+} + H{sub 2}O 2 Fe{sup 2+} + H{sub 2}O{sub 2} + 2 H{sup +}= 2 Fe{sup 3+} + 2 H{sub 2}O As(III) oxidation: HAsO{sub 2} + 2 Fe {sup 3+} + 2 H{sub 2}O = 2 Fe{sup 2+} + H{sub 3}AsO{sub 4} + 2H{sup +} HAsO{sub 2} + H{sub 2}O{sub 2} = H{sub 3}ASO{sub 4} Precipitation: Fe{sup 3+} + H{sub 3}AsO{sub 4} = FeASO{sub 4} (s) + 3 H{sup +} H{sub 3}AsO{sub 4} + n Fe(OH){sub 3} (s) = H{sub 3}ASO{sub 4} (ads) [Fe(OH){sub 3}]{sub n} (s). 15 refs., 7 figs.

  19. AB INITIO CHARACTERIZATION OF C{sup -}{sub 4}, C{sub 4}H, AND C{sub 4}H{sup -}

    SciTech Connect

    Senent, M. L.

    2010-01-10

    Using state-of-the-art theoretical methods, we investigate the stable isomers of C{sup -}{sub 4}, C{sub 4}H and C{sub 4}H{sup -}. Three of them are relevant for astrophysics and astrochemistry. These computations are performed using highly correlated ab initio methods and the aug-cc-pVXZ (X = T,Q) basis sets. In addition to the linear isomers, we predict the existence of several cyclic and branched forms for these molecules. For all the molecular species of interest here, sets of spectroscopic parameters are determined with perturbation theory, which compare quite well with experiment. For l - C{sub 4}H{sup -}(X {sup 1}SIGMA{sup +}), the quartic force field is computed at the coupled cluster level of theory. This force field is derived from full nine-dimensional potential energy surface generated close to the equilibrium geometry of this anion. Finally, we treat the thermochemistry of the hydrogen attachment and the electron attachment reactions that may lead to the formation of the C{sub 4}H{sup -} from either C{sup -}{sub 4} or C{sub 4}H.

  20. Interaction of [3H] estradiol - and [3H] monohydroxytamoxifen-estrogen receptor complexes with a monoclonal antibody.

    PubMed

    Tate, A C; DeSombre, E R; Greene, G L; Jensen, E V; Jordan, V C

    1983-01-01

    The aim of this study was to compare and contrast the interaction of estrogen [( 3H]17 beta-estradiol)- or antiestrogen [( 3H]monohydroxytamoxifen)-receptor complexes from human breast tumor cytosols with monoclonal antibodies raised to the human breast tumor estrogen receptor. Breast tumor cytosols containing estrogen receptor which sedimented as radiolabeled peaks in either the 8S, 8S and 4S, or 4S regions of sucrose density gradients, interacted with the monoclonal antibody D547 to produce a broad 9-10S peak, a broad 8S-10S peak, or a more discrete 8S peak, respectively. On high salt (0.4M KC1) sucrose density gradients the 4S ligand-receptor complex plus antibody produced a binding peak at approximately the 8S region of the gradient. These sedimentation studies with the monoclonal antibody D547, and similar studies with the monoclonal antibody D58, could detect no differences in the cytosolic estrogen receptor whether complexed with [3H]estradiol or with [3H]monohydroxytamoxifen. These observations were confirmed by Scatchard equilibrium saturation analysis and sucrose density gradient analysis of cytosols from the MCF-7 human breast cancer cell line. The antibody D547 interacted with 8S ER from these cytosols to produce a broad 8S-10S peak, but the antibody produced no change in the affinity or number of binding sites present in these cytosols. It seems, therefore, that the antigenic determinants recognized by these particular antibodies on the breast tumor cytosolic receptor are not significantly altered by the binding of either an estrogen or an antiestrogen to the receptor. PMID:6671136

  1. Synthesis Of [2h, 13c]M [2h2m 13c], And [2h3,, 13c] Methyl Aryl Sulfones And Sulfoxides

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.; Schmidt, Jurgen G.

    2004-07-20

    The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfones and [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfoxides, wherein the .sup.13 C methyl group attached to the sulfur of the sulfone or sulfoxide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing methyl aryl sulfones and methyl aryl sulfoxides.

  2. Temporal pattern of incorporation of /sup 3/H precursors into pituitary glycoproteins and their subsequent release

    SciTech Connect

    Grotjan, H.E. Jr.

    1982-04-01

    The temporal pattern of incorporation of various /sup 3/H precursors into glycoproteins by rat anterior pituitaries incubated in vitro and the release of /sup 3/H-glycoproteins was examined. (/sup 3/H)Leucine incorporation was linear with respect to time and (/sup 3/H)leucine-containing macromolecules appeared in the media in about 1 hr. The temporal pattern of (/sup 3/H)mannose incorporation and release was similar. (/sup 3/H)Galactose and (/sup 3/H)fucose were incorporated after apparent time of delays of approximately 15 min and soon thereafter (20-25 min) appeared in the medium in /sup 3/H-glycoproteins. Thus, these precursors appear to be added as terminal residues. (/sup 3/H)Glucosamine exhibited a pattern intermediate between (/sup 3/H)leucine and (/sup 3/H)fucose whereas (/sup 3/H)GlcNAc appeared to be incorporated as a terminal residue.

  3. 4-H's Influence on Advanced Training, Careers and Leadership Roles in Adulthood.

    ERIC Educational Resources Information Center

    Rockwell, S. Kay; And Others

    A study explored how adults felt their 4-H experience contributed to their selection of advanced education and/or a career and helped them with leadership skills in their occupations or community activities. To obtain data, a questionnaire was mailed to former 4-H members aged 25 to 35 in northeast Nebraska; 318 questionnaires were returned.…

  4. Bringing Carnaval Drum and Dance Traditions into 4-H Programming for Latino Youth

    ERIC Educational Resources Information Center

    Conklin-Ginop, Evelyn; Braverman, Marc T.; Caruso, Robyn; Bone, Dennis

    2011-01-01

    4-H Bloco Drum and Dance is an afterschool program that teaches adolescents drumming, dancing, and theater arts in the rich traditions of Brazilian Carnaval. Teens learn to express themselves in a variety of modalities and perform at community events. The program was developed by a community coalition that included 4-H, other youth programs, and…

  5. The First Fifty Years of the 4-H Program (Part 1).

    ERIC Educational Resources Information Center

    Van Horn, Beth E.; Flanagan, Constance A.; Thomson, Joan S.

    1998-01-01

    Reviews achievements during the first 50 years of 4-H club work, including volunteer leadership development, funding support, and response to society's needs during the war years. Demonstrates how 4-H has changed to meet societal needs while remaining true to the original mission. (SK)

  6. Birds in Your Backyard. 4-H Leaders Guide. L-5-17.

    ERIC Educational Resources Information Center

    Hawkes, Janet E.; Held Phillips, Diane

    This pocket folder of instructional materials is designed to introduce youth aged 9 to 12 to ornithology, the study of birds. The package includes a 4-H member's guide and a Leader's guide. The illustrated 4-H member's guide contains information about attracting and feeding birds. It also includes activities for cooking for birds, making bird…

  7. 4-H Healthy Living Programs with Impact: A National Environmental Scan

    ERIC Educational Resources Information Center

    Downey, Laura H.; Peterson, Donna J.; LeMenestrel, Suzanne; Leatherman, JoAnne; Lang, James

    2014-01-01

    The 4-H youth development program of the nation's 109 land-grant universities and the Cooperative Extension System is one of the largest youth development organization in the United States serving approximately six million youth. The 4-H Healthy Living initiative began in 2008 to promote achievement of optimal physical, social, and emotional…

  8. College Transition Study Shows 4-H Helps Youth Prepare for and Succeed in College

    ERIC Educational Resources Information Center

    Ratkos, Judy; Knollenberg, Lauren

    2015-01-01

    Many young adults enter college without the knowledge and skills necessary to succeed. The purpose of the study reported here was to determine if 4-H helps develop life skills needed for the transition to college and overall college success. An online survey was sent to college-attending 4-H alumni and a comparison group, with a final sample size…

  9. The Effects of Age, Gender, and 4-H Involvement on Life Skill Development

    ERIC Educational Resources Information Center

    Haas, Bruce E.; Mincemoyer, Claudia C.; Perkins, Daniel F.

    2015-01-01

    The study reported here examined the effects of age, gender, and 4-H involvement in clubs on life skill development of youth ages eight to 18 over a 12-month period. Regression analyses found age, gender, and 4-H involvement significantly influenced life skill development. Results found that females have higher levels of competencies in life…

  10. Acquisition, Custody, and Storage of Firearms Used in 4-H Shooting Sports Programs

    ERIC Educational Resources Information Center

    White, David J.; Smith, Jedediah D.

    2014-01-01

    Shooting sports has been a 4-H program offering since the 1930's. Tragic events related to the use of firearms as weapons have caused public and private entities to evaluate and consider the appropriateness of youth access to and usage of firearms. 4-H educators have the primary responsibility for managing the risk associated with shooting…

  11. Characteristics and Perceptions of 4-H Participants: Gender and Age Differences across Adolescence

    ERIC Educational Resources Information Center

    Bartoszuk, Karin; Randall, Brandy A.

    2011-01-01

    The study reported here examined 367 adolescent 4-H participants in terms of demographic, psychological, behavioral, and relational characteristics, as well as their perceptions and experiences in 4-H. Overall, participants scored high on all outcome variables except having a diverse population in their club. Older participants were more…

  12. Food Challenge: Serving Up 4-H to Non-Traditional Audiences

    ERIC Educational Resources Information Center

    Dodd, Sara; Follmer-Reece, Holly E.; Kostina-Ritchey, Erin; Reyna, Roxanna

    2015-01-01

    This article describes a novel approach for introducing 4-H to non-traditional/diverse audiences using 4-H Food Challenge. Set in a low SES and minority-serving rural school, Food Challenge was presented during the school day to all 7th grade students, with almost half voluntarily participating in an after-school club component. Program design…

  13. 4-H Youth Development: The Past, the Present, and the Future

    ERIC Educational Resources Information Center

    Borden, Lynne M.; Perkins, Daniel F.; Hawkey, Kyle

    2014-01-01

    The 4-H Program within Cooperative Extension is more than 100 years old. As we celebrate 100 years of Cooperative Extension, the foundation built by the 4-H Program serves as grounds to meet the needs of today's youth. The diversity of the youth who participate continues to grow, families continue to become less traditional, potential…

  14. Global 4-H Network: Laying the Groundwork for Global Extension Opportunities

    ERIC Educational Resources Information Center

    Major, Jennifer; Miller, Rhonda

    2012-01-01

    A descriptive study examining 4-H programs in Africa, Asia, and Europe was conducted to provide understanding and direction in the establishment of a Global 4-H Network. Information regarding structure, organizational support, funding, and programming areas was gathered. Programs varied greatly by country, and many partnered with other 4-H…

  15. 4-H and Tech Ed Partnership Gets Students Geeked about STEM

    ERIC Educational Resources Information Center

    Ivey, Debra; Quam, Greg

    2009-01-01

    This article discusses the 4-H Gateway Academies specifically designed to enhance science, technology, engineering, and math (STEM) skills and knowledge in middle school youth. The innovative summer day camps partnered Project Lead the Way--trained teachers with county 4-H staff from University of Wisconsin-Extension (UW-Extension) Cooperative…

  16. Fitting the Framework: The STEM Institute and the 4-H Essential Elements

    ERIC Educational Resources Information Center

    Sallee, Jeff; Peek, Gina G.

    2014-01-01

    Extension and 4-H youth development programs are addressing a shortage of scientists, engineers, and other related professionals by promoting science, technology, engineering, and math (STEM). This case study illustrates how the Oklahoma 4-H Youth Development program trained youth-adult teams to design and implement STEM projects. The STEM…

  17. 4-H and Forestry Afterschool Clubs: A Collaboration to Foster Stewardship Attitudes and Behaviors in Youth

    ERIC Educational Resources Information Center

    Gupta, Angela S.; Grant, Samantha; Strauss, Andrea Lorek

    2012-01-01

    The University of Minnesota Extension's 4-H and Forestry Afterschool program combined the 4-H structure and various forestry curricula to foster positive attitudes towards the environment and stewardship-related behaviors as these may serve as precursors to later choices that benefit the environment. Evaluation of third through fifth grade…

  18. Perturbation of DNA replication and cell cycle progression by commonly used ( sup 3 H)thymidine labeling protocols

    SciTech Connect

    Hoy, C.A.; Lewis, E.D.; Schimke, R.T. )

    1990-04-01

    The effect of tritiated thymidine incorporation on DNA replication was studied in Chinese hamster ovary cells. Rapidly eluting (small) DNA from cells labeled with 2 microCi of ({sup 3}H)thymidine per ml (200 microCi/mmol) for 60 min matured to a large nonelutable size within approximately 2 to 4 h, as measured by the alkaline elution technique. However, DNA from cells exposed to 10 microCi of ({sup 3}H)thymidine per ml (66 microCi/mmol) was more rapidly eluting initially and did not mature to a nonelutable size during subsequent incubation. Semiconservative DNA replication measured by cesium chloride gradient analysis of bromodeoxyuridine-substituted DNA was also found to be affected by the final specific activity of the ({sup 3}H)thymidine used in the labeling protocol. Dramatic cell cycle perturbations accompanied these effects on DNA replication, suggesting that labeling protocols commonly used to study DNA metabolism produce aberrant DNA replication and subsequent cell cycle perturbations.

  19. Proton transfer dynamics in the hydrogen bond. Inelastic neutron scattering, infrared and Raman spectra of Na 3H(SO 4) 2, K 3H(SO 4) 2 and Rb 3H(SO 4) 2

    NASA Astrophysics Data System (ADS)

    Fillaux, F.; Lautié, A.; Tomkinson, J.; Kearley, G. J.

    1991-06-01

    Na 3H(SO 4) 2, K 3H(SO 4) 2 and Rb 3H(SO 4) 2 crystals are composed of (SO 4HSO 4) -3 dimers linked by rather strong hydrogen bonds ( RO…O=2.43 Å for Na 3H(SO 4) 2, RO…O=2.48 Å for Rb 3H(SO 4) 2 and RO…O=2.49 Å for K 3H(SO 4) 2). Crystallographic data of the salts at room temperature indicate either asymmetric (Na 3H(SO 4) 2) or symmetric (K 3H(SO 4) 2 and Rb 3H(SO 4) 2) hydrogen bonds. Inelastic neutron scattering (INS), infrared and Raman spectra of crystal powders at 20 K are reported for these three compounds. The OH bending modes, which give large INS intensities, appear only weakly in the infrared. The two bending modes are degenerate in Na 3H(SO 4) 2 which has the shortest hydrogen bond but are well separated in K 3H(SO 4) 2 and Rb 3H(SO 4) 2. The OH stretching band profiles in INS are also quite different from those in the infrared. Strong INS bands at 57 and 44 cm -1 for K 3H(SO 4) 2 and Rb 3H(SO 4) 2, respectively, are assigned to 0→1 transitions in quasi-symmetric double-minimum potentials for the OH stretching coordinates. For K 3H(SO 4) 2 the frequency is unaffected by temperature between 2 and 100 K. Potential functions are calculated and the dynamics of the proton transfer are discussed. Infrared spectra are thus dominated by OH stretching transitions in asymmetric double-minimum potentials with low barriers, with relative intensities indicating a large electrical anharmonicity.

  20. U(IV)/LN(III) unexpected mixed site in polymetallic oxalato complexes. Part II. Substitution of U(IV) for Ln(III) in the new oxalates (N 2H 5) Ln(C 2O 4) 2· nH 2O ( Ln=Nd, Gd)

    NASA Astrophysics Data System (ADS)

    Chapelet-Arab, B.; Nowogrocki, G.; Abraham, F.; Grandjean, S.

    2005-10-01

    Two new hydrazinium lanthanide(III) oxalates, (N 2H 5)[Nd(C 2O 4) 2(H 2O)]·4H 2O ( 1) and (N 2H 5)[Gd(C 2O 4) 2(H 2O)]·4.5H 2O ( 2) have been prepared and their crystal structures determined by single-crystal X-ray diffraction. The crystal structures were solved by the direct methods and Fourier difference techniques, and refined by a least-squares method on the basis of F2 for all unique reflections. Crystallographic data: 1, triclinic, space group P1¯, a=8.507(3) Å, b=9.762(4), c=10.249(4) Å, α=62.378(5), β=76.681(5), γ=73.858(5), Z=2, R1=0.0335 for 172 parameters with 3430 reflections with I⩾2σ(I); 2, triclinic, space group P1¯, a=8.52(3) Å, b=9.51(3), c=10.14(3) Å, α=62.11(4), β=76.15(5), γ=73.73(5), Z=2, R1=0.0325 for 172 parameters with 1742 reflections with I⩾2σ(I). The two isotypic structures are built from a three-dimensional (3D) arrangement of lanthanide and oxalate ions. The lanthanide atom is coordinated by eight oxygen atoms from four tetradentate oxalate ions and one aqua oxygen. Alternating lanthanide and oxalate ions form six-membered rings that delimit tunnels running down three directions and occupied by hydrazinium and water molecules. Starting from these lanthanide(III) compounds two isotypic mixed Ln(III)/U(IV) oxalates, (N 2H 5) 0.75[Nd 0.75U 0.25(C 2O 4) 2(H 2O)]·4.5H 2O ( 3) and (N 2H 5) 0.75[Gd 0.75U 0.25(C 2O 4) 2(H 2O)]·4H 2O ( 4), are obtained by partial substitution of Ln(III) by U(IV) in the nine-coordinated site, the charge excess being compensated by removal of monovalent ions from the tunnels. Finally, using Na + gel, two mixed Ln(III)/U(IV) sodium oxalates, Na 0.5[Nd 0.5U 0.5(C 2O 4) 2(H 2O)]·3H 2O ( 5) and Na 0.65[Gd 0.65U 0.35(C 2O 4) 2(H 2O)]·4.5H 2O ( 6) have been obtained without any change in the 3D framework.

  1. Simple method for the growth of 4H silicon carbide on silicon substrate

    NASA Astrophysics Data System (ADS)

    Asghar, M.; Shahid, M. Y.; Iqbal, F.; Fatima, K.; Nawaz, Muhammad Asif; Arbi, H. M.; Tsu, R.

    2016-03-01

    In this study we report thermal evaporation technique as a simple method for the growth of 4H silicon carbide on p-type silicon substrate. A mixture of Si and C60 powder of high purity (99.99%) was evaporated from molybdenum boat. The as grown film was characterized by XRD, FTIR, UV-Vis Spectrophotometer and Hall Measurements. The XRD pattern displayed four peaks at 2Θ angles 28.550, 32.700, 36.100 and 58.900 related to Si (1 1 1), 4H-SiC (1 0 0), 4H-SiC (1 1 1) and 4H-SiC (2 2 2), respectively. FTIR, UV-Vis spectrophotometer and electrical properties further strengthened the 4H-SiC growth.

  2. Comparative study on pharmacokinetics and in vivo alpha1-adrenoceptor binding of [3H]tamsulosin and [3H]prazosin in rats.

    PubMed

    Ohkura, T; Yamada, S; Deguchi, Y; Kimura, R

    1999-04-01

    The plasma concentration, total radioactivity and in vivo alpha1-adrenoceptor binding in rat tissues after intravenous (i.v.) injection of [3H]tamsulosin were measured and they were compared with those obtained after the injection of [3H]prazosin. The plasma concentration of [3H]tamsulosin was consistently higher than that of [3H]prazosin, with 1.4 times greater areas under the curve (AUC(0-infinity)) of plasma concentration. As there was a significantly lower value of apparent volume of central compartment (Vd(c)) and distribution volume at steady state (Vd(ss)) for [3H]tamsulosin than [3H]prazosin with little difference in elimination rate constant (beta), the higher concentration of [3H]tamsulosin in plasma might be associated mainly with the smaller volume of distribution. The ratio of total radioactivity in tissues to the plasma unbound concentration of [3H]tamsulosin after i.v. injection of the ligand was consistently lower than that of [3H]prazosin. These observations suggest that [3H]tamsulosin is distributed in rat tissues in a more limited manner than [3H]prazosin. A significantly lower level of in vivo specific binding of [3H]tamsulosin than [3H]prazosin was observed in the spleen, heart and liver. Further, the apparent dissociation constant (Kd) and maximal number of binding sites (Bmax) for in vivo specific [3H]tamsulosin binding were considerably lower than those for [3H]prazosin binding. Therefore, these findings suggest that [3H]tamsulosin labels preferentially a subpopulation of the alpha1-adrenoceptor sites in rat tissues labeled by [3H]prazosin. In conclusion, the present study has shown that there is a significant difference in the pharmacokinetics and in vivo alpha1-adrenoceptor binding characteristics between tamsulosin and prazosin. PMID:10328564

  3. Tertiary amine-catalyzed (4 + 2) annulations of δ-acetoxy allenoates: synthesis of multisubstituted 4H-pyran and 4H-chromene.

    PubMed

    Gu, Yiting; Li, Falin; Hu, Pengfei; Liao, Daohua; Tong, Xiaofeng

    2015-03-01

    The DABCO-catalyzed divergent (4 + 2) annulations of δ-acetoxy allenoates 1 are reported. The chemical behavior of 1 under DABCO catalyst was found to be substrate dependent. Allenoate 1 with an aromatic group at δC preferentially reacted with salicylaldehyde derivative 2, delivering 4H-chromenes 3. On the other hand, allenoates 1 with an alkyl group at δC readily underwent (4 + 2) annulations with oxo diene 4 to afford 4H-pyrans 5. PMID:25692476

  4. Ultra high voltage MOS controlled 4H-SiC power switching devices

    NASA Astrophysics Data System (ADS)

    Ryu, S.; Capell, C.; Van Brunt, E.; Jonas, C.; O'Loughlin, M.; Clayton, J.; Lam, K.; Pala, V.; Hull, B.; Lemma, Y.; Lichtenwalner, D.; Zhang, Q. J.; Richmond, J.; Butler, P.; Grider, D.; Casady, J.; Allen, S.; Palmour, J.; Hinojosa, M.; Tipton, C. W.; Scozzie, C.

    2015-08-01

    Ultra high voltage (UHV, >15 kV) 4H-silicon carbide (SiC) power devices have the potential to significantly improve the system performance, reliability, and cost of energy conversion systems by providing reduced part count, simplified circuit topology, and reduced switching losses. In this paper, we compare the two MOS based UHV 4H-SiC power switching devices; 15 kV 4H-SiC MOSFETs and 15 kV 4H-SiC n-IGBTs. The 15 kV 4H-SiC MOSFET shows a specific on-resistance of 204 mΩ cm2 at 25 °C, which increased to 570 mΩ cm2 at 150 °C. The 15 kV 4H-SiC MOSFET provides low, temperature-independent, switching losses which makes the device more attractive for applications that require higher switching frequencies. The 15 kV 4H-SiC n-IGBT shows a significantly lower forward voltage drop (VF), along with reasonable switching performance, which make it a very attractive device for high voltage applications with lower switching frequency requirements. An electrothermal analysis showed that the 15 kV 4H-SiC n-IGBT outperforms the 15 kV 4H-SiC MOSFET for applications with switching frequencies of less than 5 kHz. It was also shown that the use of a carrier storage layer (CSL) can significantly improve the conduction performance of the 15 kV 4H-SiC n-IGBTs.

  5. McDonnell F2H-3 Banshee

    NASA Technical Reports Server (NTRS)

    1957-01-01

    McDonnell F2H-3 Banshee: To more clearly mark the operators of this McDonnell F2H-3 Banshee, the 'VY' of Navy has been painted out and the appropriate lettering to spell NACA has been applied. Note that the second 'A' is of a different shape than the first. The 'Banjo' retained Navy titles on the wings, however.

  6. A Search for Interstellar Oxiranecarbonitrile (C3H3NO)

    NASA Technical Reports Server (NTRS)

    Dicken, J. E.; Irvine, W. M.; Ohishi, M.; Arrhenius, G.; Bauder, A.; Mueller, F.; Eschenmoser, A.

    1996-01-01

    We report a search in cold, quiescent and in 'hot core' type interstellar molecular clouds for the small cyclic molecule oxiranecarbonitrile (C3H3NO), which has been suggested as a precursor of important prebiotic molecules. We have determined upper limits to the column density and fractional abundance for the observed sources and find that, typically, the fractional abundance by number relative to molecular hydrogen Of C3H3NO is less than a few times 10(exp -10). This limit is one to two orders of magnitude less than the measured abundance of such similarly complex species as CH3CH2CN and HCOOCH3 in well-studied hot cores. A number of astrochemical discoveries were made, including the first detection of the species CH3CH2CN in the massive star-forming clouds G34.3+0.2 and W51M and the first astronomical detections of some eight rotational transitions of CH3CH2CN, CH3CCH, and HCOOCH3. In addition, we found 8 emission lines in the 89 GHz region and 18 in the 102 GHz region which we were unable to assign.

  7. Effective theory of 3H and 3He

    NASA Astrophysics Data System (ADS)

    König, Sebastian; Grießhammer, Harald W.; Hammer, H.-W.; van Kolck, U.

    2016-06-01

    We present a new perturbative expansion for pionless effective field theory with Coulomb interactions in which at leading order (LO) the spin-singlet nucleon–nucleon channels are taken in the unitarity limit. Presenting results up to next-to-leading order for the Phillips line and the neutron–deuteron doublet-channel phase shift, we find that a perturbative expansion in the inverse {}1{S}0 scattering lengths converges rapidly. Using a new systematic treatment of the proton–proton sector that isolates the divergence due to one-photon exchange, we renormalize the corresponding contribution to the {}3{{H}} –{}3{He} binding energy splitting and demonstrate that the Coulomb force in pionless EFT is a completely perturbative effect in the trinucleon bound-state regime. In our new expansion, the LO is exactly isospin-symmetric. At next-to-leading order, we include isospin breaking via the Coulomb force and two-body scattering lengths, and find for the energy splitting {({E}B{(}3{He})-{E}B{(}3{{H}}))}{NLO}\\quad =(-0.86+/- 0.17)\\quad {MeV}.

  8. A search for interstellar oxiranecarbonitrile (C3H3NO).

    PubMed

    Dickens, J E; Irvine, W M; Ohishi, M; Arrhenius, G; Pitsch, S; Bauder, A; Muller, F; Eschenmoser, A

    1996-04-01

    We report a search in cold, quiescent and in 'hot core' type interstellar molecular clouds for the small cyclic molecule oxiranecarbonitrile (C3H3NO), which has been suggested as a precursor of important prebiotic molecules. We have determined upper limits to the column density and fractional abundance for the observed sources and find that, typically, the fractional abundance by number relative to molecular hydrogen of C3H3NO is less than a few times 10(-10). This limit is one to two orders of magnitude less than the measured abundance of such similarly complex species as CH3CH2CN and HCOOCH3 in well-studied hot cores. A number of astrochemical discoveries were made, including the first detection of the species CH3CH2CN in the massive star-forming clouds G34.3+0.2 and W51M and the first astronomical detections of some eight rotational transitions of CH3CH2CN, CH3CCH, and HCOOCH3. In addition, we found 8 emission lines in the 89 GHz region and 18 in the 102 GHz region which we were unable to assign. PMID:11536752

  9. The 3H-3He Charge Radii Difference

    NASA Astrophysics Data System (ADS)

    Myers, L. S.; Arrington, J. R.; Higinbotham, D. W.

    2016-03-01

    The upcoming E12-14-009 [1] experiment at Jefferson Lab will determine the ratio of the electric form factors for the A=3 mirror nuclei 3He and 3H. The measurement will use a 1.1 GeV electron beam, a special collimator plate to allow for simultaneous optics measurements, and the low-activity tritium target being prepared for Jefferson Lab. By observing the dependence of the form factor ratio as a function of Q2 over 0.05-0.09 GeV2, the dependence of the radii extraction on the shape of the form factors is minimized. As a result, we anticipate the uncertainty of the extracted charge radii difference to be 0.03 fm, a reduction of 70% from the current measurement. Using precise measurements of the 3He charge radius from isotopic shift or μHe measurements [2-4], we can deduce the absolute 3H charge radius. The results will provide a direct comparison to recent calculations of the charge radii.

  10. Evidence for triangular D3h symmetry in 12C.

    PubMed

    Marín-Lámbarri, D J; Bijker, R; Freer, M; Gai, M; Kokalova, Tz; Parker, D J; Wheldon, C

    2014-07-01

    We report a measurement of a new high spin Jπ=5- state at 22.4(2) MeV in 12C which fits very well to the predicted (ground state) rotational band of an oblate equilateral triangular spinning top with a D3h symmetry characterized by the sequence 0+, 2+, 3-, 4±, 5- with almost degenerate 4+ and 4- (parity doublet) states. Such a D3h symmetry was observed in triatomic molecules, and it is observed here for the first time in nuclear physics. We discuss a classification of other rotation-vibration bands in 12C such as the (0+) Hoyle band and the (1-) bending mode band and suggest measurements in search of the predicted ("missing") states that may shed new light on clustering in 12C and light nuclei. In particular, the observation (or nonobservation) of the predicted ("missing") states in the Hoyle band will allow us to conclude the geometrical arrangement of the three alpha particles composing the Hoyle state at 7.654 MeV in 12C. PMID:25032922

  11. Beryllium-induced immune response in C3H mice

    SciTech Connect

    Benson, J.M.; Bice, D.E.; Nikula, K.J.

    1995-12-01

    Studies conducted at ITRI over the past several years have investigated whether Beagle dogs, monkeys, and mice are suitable models for human chronic beryllium-induced lung disease (CBD). Recent studies have focused on the histopathological and immunopathological changes occurring in A/J and C3H/HeJ mice acutely exposed by inhalation to Be metal. Lung lesions in both strains of mice included focal lymphocyte aggregates comprised primarily of B lymphocytes and lesser amounts of T-helper lymphocytes and microgranulomas consisting chiefly of macrophages and T-helper lymphocytes. The distribution of proliferating cells within the microgranulomas was similar to the distribution of T-helper cells. These results strongly suggested that A/J and C3H/HeJ mice responded to inhaled Be metal in a fashion similar to humans in terms of pulmonary lesions and the apparent in situ proliferation of T-helper cells. Results of these studies confirm lymphocyte involvement in the pulmonary response to inhaled Be metal.

  12. Dating degassed groundwater with 3H/3He

    NASA Astrophysics Data System (ADS)

    Visser, Ate; Broers, Hans Peter; Bierkens, Marc F. P.

    2007-10-01

    The production of gases in groundwater under contaminated locations by geochemical and biological processes is not uncommon. Degassing of these gases from groundwater and repartitioning of noble gases between water and gas phase distorts groundwater dating by 3H/3He. We observed noble gas concentrations below atmospheric equilibrium in 20 out of 34 groundwater samples from agriculturally polluted sandy areas in the Netherlands. From the absence of nitrate in degassed samples, we conclude that denitrification causes degassing. The 22Ne/20Ne ratios show that degassing had attained solubility equilibrium and had not caused isotopic fractionation by diffusion. To correct for the loss of tritiogenic 3He due to degassing, we present a single-step equilibrium degassing model. We use the total dissolved gas pressure at the monitoring screen to estimate the depth and timing of degassing, which is essential to estimate travel times from degassed samples. By propagating the uncertainties in the underlying measurements and assumptions through the travel time calculations, we found a travel time uncertainty of 3 years (a). We therefore conclude that 3H/3He dating can produce valuable information on groundwater flow even at sites with strong degassing.

  13. Investigations of 3C-SiC inclusions in 4H-SiC epilayers on 4H-SiC single crystal substrates

    SciTech Connect

    Si, W.; Dudley, M.; Kong, H.S.; Sumakeris, J.; Carter, C. Jr.

    1997-03-01

    Synchrotron white beam x-ray topography (SWBXT) and Nomarski optical microscopy (NOM) have been used to characterize 4H-SiC epilayers and to study the character of triangular inclusions therein. 4H-SiC substrates misoriented by a range of angles from (0001), as well as (1 1{bar 0}0) and (11 2{bar 0}) oriented substrates were used. No evidence was found for the nucleation of 3C-SiC inclusions at superscrew dislocations (along the [0001] axis) in the 4H-SiC substrates. Increasing the off-axis angle of the substrates from 3.5 to 6.5{degree} was found to greatly suppress the formation of the triangular inclusions. In the case of substrates misoriented by 8.0{degree} from (0001) toward [112{bar 0}], the triangular inclusions were virtually eliminated. The crystalline quality of 4H-SiC epilayers grown on the substrates misoriented by 8.0{degree} from (0001) was very good. For the (11{bar 0}0) and (112{bar 0}) samples, there is no indication of 3C-SiC inclusions in the epilayers. Possible formation mechanisms and the morphology of 3C-SiC inclusions are discussed. 17 refs., 13 figs.

  14. Wiggles and Wags: Dog 1--Fun Activities for You and Your Dog. 4-H Skills for Life Animal Series. National 4-H Curriculum. BU-08166

    ERIC Educational Resources Information Center

    National 4-H Council, 2005

    2005-01-01

    These guides are activity guides. Several fact-filled books about dogs are listed as resources on this guide. The activities are active, hands-on, and engaging and are guided by the 4-H motto: Learning by Doing. As youth explore a dog project topic of interest to them, they also practice essential life skills. Although a few dog project youth will…

  15. Bindings of /sup 3/H-prazosin and /sup 3/H-yohimbine to alpha adrenoceptors in the guinea-pig stomach

    SciTech Connect

    Taniguchi, T.; Nishikawa, H.

    1988-01-01

    Alpha adrenoceptor subtypes have been investigated by radioligand binding study in guinea-pig stomach using /sup 3/H-prazosin and /sup 3/H-yohimbine. The specific /sup 3/H-prazosin binding to guinea-pig stomach was saturable and of high affinity with a Bmax of 33 fmol/mg protein. Specific /sup 3/H-yohimbine binding to the tissue was also saturable and of high affinity with a Bmax of 150 fmol/mg protein. Adrenergic drugs competed for /sup 3/H-prazosin binding in order of prazosin > phentolamine > methoxamine > norepinephrine > clonidine > epinephrine > yohimbine. These drugs competed for /sup 3/H-yohimbine binding in order of yohimbine > phentolamine > clonidine > epinephrine > norepinephrine > prazosin > methoxamine. They also examined whether dopamine receptors exist in guinea-pig stomach, using radioligand binding study. Specific binding of /sup 3/H-spiperone, /sup 3/H-apomorphine, /sup 3/H-dopamine and /sup 3/H-domperidone was not detectable in the stomach. Dopaminergic drugs such as dopamine, haloperidol, domperidone and sulpiride competed for /sup 3/H-prazosin binding in order of haloperidol > domperidone > dopamine > sulpiride. Metoclopramide, sulpiride and dopamine competed for /sup 3/H-yohimbine binding in order of metoclopramide > sulpiride > dopamine.

  16. Using Multiple Youth Programming Delivery Modes to Drive the Development of Social Capital in 4-H Participants

    ERIC Educational Resources Information Center

    Kinsey, Sharon

    2013-01-01

    This article focuses on how 4-H youth participants are building social capital, or connections among individuals and community members, through their 4-H experiences. These experiences can be seen through the lens of such 4-H delivery modes as the traditional 4-H club, after-school programs, and school enrichment programs. In addition, other…

  17. Using 14C and 3H to understand groundwater flow and recharge in an aquifer window

    NASA Astrophysics Data System (ADS)

    Atkinson, A. P.; Cartwright, I.; Gilfedder, B. S.; Cendón, D. I.; Unland, N. P.; Hofmann, H.

    2014-06-01

    Knowledge of groundwater residence times and recharge locations are vital to the sustainable management of groundwater resources. Here we investigate groundwater residence times and patterns of recharge in the Gellibrand Valley, southeast Australia, where outcropping aquifer sediments of the Eastern View Formation form an "aquifer window" that may receive diffuse recharge and recharge from the Gellibrand River. To determine recharge patterns and groundwater flowpaths, environmental isotopes (3H, 14C, δ13C, δ18O, δ2H) are used in conjunction with groundwater geochemistry and continuous monitoring of groundwater elevation and electrical conductivity. Despite the water table fluctuating by 0.9-3.7 m annually producing estimated recharge rates of 90 and 372 mm yr-1, residence times of shallow (11-29 m) groundwater determined by 14C ages are between 100 and 10 000 years. 3H activities are negligible in most of the groundwater and groundwater electrical conductivity in individual areas remains constant over the period of study. Although diffuse local recharge is evident, the depth to which it penetrates is limited to the upper 10 m of the aquifer. Rather, groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High, and acts as a regional discharge zone where upward head gradients are maintained annually, limiting local recharge. Additionally, the Gellibrand River does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10 000 years BP to the present day are interpreted to indicate an increase in recharge rates on the Barongarook High.

  18. Using 14C and 3H to understand groundwater flow and recharge in an aquifer window

    NASA Astrophysics Data System (ADS)

    Atkinson, A. P.; Cartwright, I.; Gilfedder, B. S.; Cendón, D. I.; Unland, N. P.; Hofmann, H.

    2014-12-01

    Knowledge of groundwater residence times and recharge locations is vital to the sustainable management of groundwater resources. Here we investigate groundwater residence times and patterns of recharge in the Gellibrand Valley, southeast Australia, where outcropping aquifer sediments of the Eastern View Formation form an "aquifer window" that may receive diffuse recharge from rainfall and recharge from the Gellibrand River. To determine recharge patterns and groundwater flow paths, environmental isotopes (3H, 14C, δ13C, δ18O, δ2H) are used in conjunction with groundwater geochemistry and continuous monitoring of groundwater elevation and electrical conductivity. The water table fluctuates by 0.9 to 3.7 m annually, implying recharge rates of 90 and 372 mm yr-1. However, residence times of shallow (11 to 29 m) groundwater determined by 14C are between 100 and 10 000 years, 3H activities are negligible in most of the groundwater, and groundwater electrical conductivity remains constant over the period of study. Deeper groundwater with older 14C ages has lower δ18O values than younger, shallower groundwater, which is consistent with it being derived from greater altitudes. The combined geochemistry data indicate that local recharge from precipitation within the valley occurs through the aquifer window, however much of the groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High. The Gellibrand Valley is a regional discharge zone with upward head gradients that limits local recharge to the upper 10 m of the aquifer. Additionally, the groundwater head gradients adjacent to the Gellibrand River are generally upwards, implying that it does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10

  19. Phthalocyanines of a novel structure: Dinaphthotetraazaporphyrins with D[sub 2h] symmetry

    SciTech Connect

    Kobayashi, Nagao; Ashida, Tohru; Osa, Tetsuo Tohoku Univ., Kathahira, Sendai ); Konami, Hideo

    1994-04-27

    Phthalocyanines (Pcs) are compounds in which a benzene ring is fused to each of the four pyrrole rings of tetraazaporphyrins (TAPs). In addition to traditional uses as dyes and in xerography, they are now rapidly increasing in importance in many fields such as batteries, photodynamic cancer therapy, chemical sensors, molecular metals, and liquid crystals. Two naphthalene molecule-fused tetraazaporphyrins (TAPs) with D[sub 2h] symmetry have been synthesized, and some of their spectroscopic and electrochemical properties are reported. These compounds are structural isomers of phthalocyanines (Pcs) in the sense that four benzene units are fused to the TAP skeleton. In contrast to MPcs (M = metal) with D[sub 4h] symmetry, both the Q[sub o-o] and Soret bands split into two as a result of the lowering of the molecular symmetry. Magnetic circular dichroism (MCD) shows Faraday B terms corresponding to the peaks and shoulders of the electronic absorption spectra, indicating that no degenerate state is included. The fluorescence quantum yield of the zinc complex is much smaller than in ZnPc with D[sub 4h] symmetry. The electronic absorption and electrochemical redox data of these complexes are reproduced by molecular orbital (MO) calculations within the framework of the Pariser-Parr-Pople (PPP) approximation. The results are compared with those of Pcs and mononaphtho-TAPs.

  20. Synthesis and characterization of 4-aryl-4H-chromenes from H-cardanol.

    PubMed

    Rao, Hulluru Surya Prakash; Kamalraj, Mani

    2014-09-01

    We have synthesized and characterized a variety of fat-soluble, low-melting and medicinally useful 4-aryl-4H-chromenes from H-cardanol (side-chain perhydrogenated cardanol, 3-pentadecylphenol), a renewable and low-cost product from locally grown cashew nut trees (Anacardium occidentale L.). We incorporated H-cardanol into the aromatic rings of either 4H-chromene or phenol, or both. Substitution of C4SMe in N-methyl-4-(methylthio)-3-nitro-4H-chromene-2-amines with H-cardanol was regio-specific at the C6 position. PMID:25918806

  1. SWSextantis stars: the dominant population of cataclysmic variables with orbital periods between 3 and 4h

    NASA Astrophysics Data System (ADS)

    Rodríguez-Gil, P.; Gänsicke, B. T.; Hagen, H.-J.; Araujo-Betancor, S.; Aungwerojwit, A.; Allende Prieto, C.; Boyd, D.; Casares, J.; Engels, D.; Giannakis, O.; Harlaftis, E. T.; Kube, J.; Lehto, H.; Martínez-Pais, I. G.; Schwarz, R.; Skidmore, W.; Staude, A.; Torres, M. A. P.

    2007-06-01

    We present time-series optical photometry of five new cataclysmic variables (CVs) identified by the Hamburg Quasar Survey (HQS). The deep eclipses observed in HS 0129+2933 (= TT Tri), HS 0220+0603 and HS 0455+8315 provided very accurate orbital periods of 3.35129827(65), 3.58098501(34) and 3.56937674(26) h, respectively. HS 0805+3822 shows grazing eclipses and has a likely orbital period of 3.2169(2) h. Time-resolved optical spectroscopy of the new CVs (with the exception of HS 0805+3822) is also presented. Radial velocity studies of the Balmer emission lines provided an orbital period of 3.55 h for HS 1813+6122, which allowed us to identify the observed photometric signal at 3.39 h as a negative superhump wave. The spectroscopic behaviour exhibited by all the systems clearly identifies them as new SW Sextantis (SW Sex) stars. HS 0220+0603 shows unusual NII and SiII emission lines suggesting that the donor star may have experienced nuclear evolution via the CNO cycle. These five new additions to the class increase the number of known SW Sex stars to 35. Almost 40 per cent of the total SW Sex population do not show eclipses, invalidating the requirement of eclipses as a defining characteristic of the class and the models based on a high orbital inclination geometry alone. On the other hand, as more SW Sex stars are identified, the predominance of orbital periods in the narrow 3-4.5 h range is becoming more pronounced. In fact, almost half the CVs which populate the 3-4.5 h period interval are definite members of the class. The dominance of SW Sex stars is even stronger in the 2-3 h period gap, where they make up 55 per cent of all known gap CVs. These statistics are confirmed by our results from the HQS CVs. Remarkably, 54 per cent of the Hamburg nova-like variables have been identified as SW Sex stars with orbital periods in the 3-4.5 h range. The observation of this pile-up of systems close to the upper boundary of the period gap is difficult to reconcile with the

  2. Determination of muscle protein synthesis rates in fish using (2)H2O and (2)H NMR analysis of alanine.

    PubMed

    Marques, Cátia; Viegas, Filipa; Rito, João; Jones, John; Viegas, Ivan

    2016-09-15

    Following administration of deuterated water ((2)H2O), the fractional synthetic rate (FSR) of a given endogenous protein can be estimated by (2)H-enrichment quantification of its alanine residues. Currently, this is measured by mass spectrometry following a derivatization procedure. Muscle FSR was measured by (1)H/(2)H NMR analysis of alanine from seabass kept for 6 days in 5% (2)H-enriched saltwater, following acid hydrolysis and amino acid isolation by cation-exchange chromatography of muscle tissue. The analysis is simple and robust, and provides precise measurements of excess alanine (2)H-enrichment in the 0.1-0.4% range from 50 mmol of alanine recovered from muscle protein. PMID:27418547

  3. Encapsulated scintillators monitor /sup 3/H-solute concentrations

    SciTech Connect

    Kirk, G.; Gruner, S.

    1982-02-01

    The short range of the /sup 3/H beta allows shielding of microbeds of scintillator by a several um thick coating of a water based gel. Gels may be used which are permeable to a wide variety of tritiated molecules. Thus, the light output of a mixture of the coated beads and a solution of the tritiated compound is proportional to the solution concentration of the tritiated substance. The mixture may also contain particles to which the gel is impermeable, such as cells, vesicles, large proteins, etc., but which can alter the concentration of the tritiated compound by uptake or release. In this case, the light output monitors the fractional uptake of the tritiated material. The design criteria for encapsulating the scintillators and dynamically monitoring the scintillation output are discussed. A simple method for encapsulating plastic scintillator microbeads, suitable for monitoring slow concentration changes, is described and tested.

  4. Ascorbic acid and striatal transport of (/sup 3/H)1-methyl-4-phenylpyridine (MPP/sup +/) and (/sup 3/H)dopamine

    SciTech Connect

    Debler, E.A.; Hashim, A.; Lajtha, A.; Sershen, H.

    1988-01-01

    The inhibition of uptake of (/sup 3/H)dopamine and (/sup 3/H)1-methyl-4-phenylpyridine (MPP/sup +/) was examined in mouse striatal synaptosomal preparations. Kinetic analysis indicated that ascorbic acid is a noncompetitive inhibitor of (/sup 3/H)MPP/sup +/ uptake. No inhibition of (/sup 3/H)dopamine uptake is observed. The dopamine uptake blockers, GBR-12909, cocaine, and mazindol strongly inhibit (IC/sub 50/ < 1 ..mu..M) both (/sup 3/H)dopamine and (/sup 3/H)MPP/sup +/ transport. Nicotine, its metabolites, and other tobacco alkaloids are weak inhibitors except 4-phenylpyridine and lobeline, which are moderate inhibitors of both (/sup 3/H)dopamine and (/sup 3/H)MPP/sup +/ uptake. These similarities in potencies are in agreement with the suggestion that (/sup 3/H)MPP/sup +/ and (/sup 3/H) are transported by the same carrier. The differences observed in the alteration of dopaminergic transport and mazindol binding by ascorbic acid suggest that ascorbic acid's effects on (/sup 3/H)MPP/sup +/ transport are related to translocation and/or dissociation processes occurring subsequent to the initial binding event.

  5. Rate constants for reactions between atmospheric reservoir species. 2. H sub 2 O

    SciTech Connect

    Hatakeyama, Shiro; Leu, Mingtaun )

    1989-07-27

    The kinetics of the reactions of H{sub 2}O with ClONO{sub 2}, N{sub 2}O{sub 5}, O{sub 3}, and COCl{sub 2} have been investigated by using a large-volume static cell and a Fourier transform infrared spectrometer at 296 K. Upper limits for the homogeneous gas-phase reaction rate constants of the ClONO{sub 2} + H{sub 2}O, N{sub 2}O{sub 5} + H{sub 2}O, O{sub 3} + H{sub 2}O, and COCl{sub 2} + H{sub 2}O reactions were found to be 3.4 {times} 10{sup {minus}21}, 2.8 {times} 10{sup {minus}21}, 1.1 {times} 10{sup {minus}22}, and 1.2 {times} 10{sup {minus}23}, respectively (all in units of cm{sup 3} s{sup {minus}1}), based on the observed decay rates of ClONO{sub 2}, N{sub 2}O{sub 5}, O{sub 3}, and COCl{sub 2}. Product analyses gave 0.82 {plus minus} 0.07 for the yield of HNO{sub 3} in the ClONO{sub 2} + H{sub 2}O {yields} HOCl + HNO{sub 3} reaction and 1.1 {plus minus} 0.3 for the yield of HNO{sub 3} from the N{sub 2}O{sub 5} + H{sub 2}O {yields} 2HNO{sub 3} reaction. The quoted error represents one standard deviation of the measurement. An attempt was also made to monitor possible reaction products such as H{sub 2}O{sub 2} for the O{sub 3} + H{sub 2}O reaction, and CO{sub 2} or HCl for the COCl{sub 2} + H{sub 2}O reaction. These results may be important in the elucidation of the springtime Antarctic ozone depletion over the past decade. The implication for NO{sub x} chemistry in the nighttime troposphere based on their results of the N{sub 2}O{sub 5} + H{sub 2}O reaction will be discussed.

  6. Al4H7− is a resilient building block for aluminum hydrogen cluster materials

    PubMed Central

    Roach, P. J.; Reber, A. C.; Woodward, W. H.; Khanna, S. N.; Castleman, A. W.

    2007-01-01

    The formation and oxygen etching of AlnHm− clusters are characterized in a flow reactor experiment with first-principles theoretical investigations to demonstrate the exceptional stability of Al4H7−. The origin of the preponderance of Al4H7− in the mass spectra of hydrogenated aluminum anions and its resistance to O2 etching are discussed. Al4H7− is shown to have the ability to bond with ionic partners to form stable hydrides through addition of an alkali atom [XAl4H7 (X = Li-Cs)]. An intuitive model that can predict the existence of stable hydrogenated cluster species is proposed. The potential synthetic utility of the superatom assemblies built on these units is addressed. PMID:17823245

  7. Ohio 4-H Agents' and Volunteer Leaders' Perceptions of the Volunteer Leadership Development Program.

    ERIC Educational Resources Information Center

    Kwarteng, Joseph A.; And Others

    1988-01-01

    This study found that six areas of volunteer leadership development are important to volunteers and 4-H agents. The areas are (1) recruiting, (2) training, (3) motivation, (4) recognition, (5) retention, and (6) supervision. (JOW)

  8. Characterization of deep electron traps in 4H-SiC Junction Barrier Schottky rectifiers

    NASA Astrophysics Data System (ADS)

    Gelczuk, Ł.; Dąbrowska-Szata, M.; Sochacki, M.; Szmidt, J.

    2014-04-01

    Conventional deep level transient spectroscopy (DLTS) technique was used to study deep electron traps in 4H-SiC Junction Barrier Schottky (JBS) rectifiers. 4H-SiC epitaxial layers, doped with nitrogen and grown on standard n+-4H-SiC substrates were exposed to low-dose aluminum ion implantation process under the Schottky contact in order to form both JBS grid and junction termination extension (JTE), and assure good rectifying properties of the diodes. Several deep electron traps were revealed and attributed to impurities or intrinsic defects in 4H-SiC epitaxial layers, on the basis of comparison of their electrical parameters (i.e. activation energies, apparent capture cross sections and concentrations) with previously published results.

  9. 3,4-Methylenedioxyamphetamine (MDA) analogues exhibit differential effects on synaptosomal release of 3H-dopamine and 3H-5-hydroxytryptamine

    SciTech Connect

    McKenna, D.J.; Guan, X.M.; Shulgin, A.T. )

    1991-03-01

    The effect of various analogues of the neurotoxic amphetamine derivative, MDA (3,4-methylenedioxyamphetamine) on carrier-mediated, calcium-independent release of 3H-5-HT and 3H-DA from rat brain synaptosomes was investigated. Both enantiomers of the neurotoxic analogues MDA and MDMA (3,4-methylenedioxymethamphetamine) induce synaptosomal release of 3H-5-HT and 3H-DA in vitro. The release of 3H-5-HT induced by MDMA is partially blocked by 10(-6) M fluoxetine. The (+) enantiomers of both MDA and MDMA are more potent than the (-) enantiomers as releasers of both 3H-5-HT and 3H-DA. Eleven analogues, differing from MDA with respect to the nature and number of ring and/or side chain substituents, also show some activity in the release experiments, and are more potent as releasers of 3H-5-HT than of 3H-DA. The amphetamine derivatives {plus minus}fenfluramine, {plus minus}norfenfluramine, {plus minus}MDE, {plus minus}PCA, and d-methamphetamine are all potent releasers of 3H-5-HT and show varying degrees of activity as 3H-DA releasers. The hallucinogen DOM does not cause significant release of either 3H-monoamine. Possible long-term serotonergic neurotoxicity was assessed by quantifying the density of 5-HT uptake sites in rats treated with multiple doses of selected analogues using 3H-paroxetine to label 5-HT uptake sites. In the neurotoxicity study of the compounds investigated, only (+)MDA caused a significant loss of 5-HT uptake sites in comparison to saline-treated controls. These results are discussed in terms of the apparent structure-activity properties affecting 3H-monoamine release and their possible relevance to neurotoxicity in this series of MDA congeners.

  10. 3,4-Methylenedioxyamphetamine (MDA) analogues exhibit differential effects on synaptosomal release of 3H-dopamine and 3H-5-hydroxytryptamine.

    PubMed

    McKenna, D J; Guan, X M; Shulgin, A T

    1991-03-01

    The effect of various analogues of the neurotoxic amphetamine derivative, MDA (3,4-methylenedioxyamphetamine) on carrier-mediated, calcium-independent release of 3H-5-HT and 3H-DA from rat brain synaptosomes was investigated. Both enantiomers of the neurotoxic analogues MDA and MDMA (3,4-methylenedioxymethamphetamine) induce synaptosomal release of 3H-5-HT and 3H-DA in vitro. The release of 3H-5-HT induced by MDMA is partially blocked by 10(-6) M fluoxetine. The (+) enantiomers of both MDA and MDMA are more potent than the (-) enantiomers as releasers of both 3H-5-HT and 3H-DA. Eleven analogues, differing from MDA with respect to the nature and number of ring and/or side chain substituents, also show some activity in the release experiments, and are more potent as releasers of 3H-5-HT than of 3H-DA. The amphetamine derivatives (+/-)fenfluramine, (+/-)norfenfluramine, (+/-)MDE, (+/-)PCA, and d-methamphetamine are all potent releasers of 3H-5-HT and show varying degrees of activity as 3H-DA releasers. The hallucinogen DOM does not cause significant release of either 3H-monoamine. Possible long-term serotonergic neurotoxicity was assessed by quantifying the density of 5-HT uptake sites in rats treated with multiple doses of selected analogues using 3H-paroxetine to label 5-HT uptake sites. In the neurotoxicity study of the compounds investigated, only (+)MDA caused a significant loss of 5-HT uptake sites in comparison to saline-treated controls. These results are discussed in terms of the apparent structure-activity properties affecting 3H-monoamine release and their possible relevance to neurotoxicity in this series of MDA congeners. PMID:1829838

  11. Selective labeling of serotonin uptake sites in rat brain by (/sup 3/H)citalopram contrasted to labeling of multiple sites by (/sup 3/H)imipramine

    SciTech Connect

    D'Amato, R.J.; Largent, B.L.; Snowman, A.M.; Snyder, S.H.

    1987-07-01

    Citalopram is a potent and selective inhibitor of neuronal serotonin uptake. In rat brain membranes (/sup 3/H)citalopram demonstrates saturable and reversible binding with a KD of 0.8 nM and a maximal number of binding sites (Bmax) of 570 fmol/mg of protein. The drug specificity for (/sup 3/H)citalopram binding and synaptosomal serotonin uptake are closely correlated. Inhibition of (/sup 3/H)citalopram binding by both serotonin and imipramine is consistent with a competitive interaction in both equilibrium and kinetic analyses. The autoradiographic pattern of (/sup 3/H)citalopram binding sites closely resembles the distribution of serotonin. By contrast, detailed equilibrium-saturation analysis of (/sup 3/H)imipramine binding reveals two binding components, i.e., high affinity (KD = 9 nM, Bmax = 420 fmol/mg of protein) and low affinity (KD = 553 nM, Bmax = 8560 fmol/mg of protein) sites. Specific (/sup 3/H)imipramine binding, defined as the binding inhibited by 100 microM desipramine, is displaced only partially by serotonin. Various studies reveal that the serotonin-sensitive portion of binding corresponds to the high affinity sites of (/sup 3/H)imipramine binding whereas the serotonin-insensitive binding corresponds to the low affinity sites. Lesioning of serotonin neurons with p-chloroamphetamine causes a large decrease in (/sup 3/H)citalopram and serotonin-sensitive (/sup 3/H)imipramine binding with only a small effect on serotonin-insensitive (/sup 3/H)imipramine binding. The dissociation rate of (/sup 3/H)imipramine or (/sup 3/H)citalopram is not altered by citalopram, imipramine or serotonin up to concentrations of 10 microM. The regional distribution of serotonin sensitive (/sup 3/H)imipramine high affinity binding sites closely resembles that of (/sup 3/H)citalopram binding.

  12. Xyloglucan undergoes interpolymeric transglycosylation during binding to the plant cell wall in vivo: evidence from 13C/3H dual labelling and isopycnic centrifugation in caesium trifluoroacetate.

    PubMed Central

    Thompson, J E; Smith, R C; Fry, S C

    1997-01-01

    Xyloglucan from the walls of Rosa cells that had been cultured on [12C]- or [13C]-glucose formed bands in caesium trifluoroacetate with mean buoyant densities of 1.575 or 1.616 g/ml respectively. Incubation of a mixture of [13C,3H]xyloglucan and [12C,1H]xyloglucan in the presence of xyloglucan endotransglycosylase (XET) activity caused the mean buoyant density of the radioactive material to decrease, indicating that interpolymeric transglycosylation could be detected in vitro. We used two 13C/3H-dual-labelling protocols to look for interpolymeric transglycosylation in vivo. In protocol A, [13C]glucose-grown Rosa cells were transferred into [12C]glucose medium 6 h after a approximately 2 h pulse of l-[1-3H]arabinose (which radiolabels the xylose residues of xyloglucan). The mean buoyant density of the wall-bound [3H]xyloglucan decreased during the following 7 days in culture. This indicates that, during or after the wall-binding of newly synthesized [12C,1H]xyloglucan, it became covalently attached to previously wall-bound [13C, 3H]xyloglucan. In protocol B, [12C]glycerol- or [12C]glucose-grown Rosa cells were transferred into [13C]glucose medium, 20 or 60 min before a approximately 2 h pulse of [3H]arabinose. The buoyant density of the earliest wall-bound [3H]xyloglucan showed that it had a 12C/13C ratio of approximately 1:1. This indicates that, during (or, implausibly, before) wall-binding, the newly synthesized [13C, 3H]xyloglucan became covalently attached to previously synthesized [12C]xyloglucan. During the following 7 days in culture, the mean buoyant density of the [3H]xyloglucan increased, showing that later-synthesized [13C,1H]xyloglucan can be covalently attached to previously wall-bound [12C,13C,3H]xyloglucan. The only known mechanism by which segments of xyloglucans could become covalently attached to each other in the cell wall is by interpolymeric transglycosylation catalysed by XET. We conclude that XET-catalysed interpolymeric transglycosylation

  13. Organic Compounds in the C3H6O3 Family: Microwave Spectrum of cis-cis Dimethyl Carbonate

    NASA Astrophysics Data System (ADS)

    McGuire, B. A.; Widicus Weaver, S. L.; Lovas, F. J.; Plusquellic, D. F.; Blake, G. A.

    2011-05-01

    A number of recent spectroscopic and observational efforts have focused on simple sugars and sugar alcohols because of their importance in prebiotic astro- chemistry. The simplest sugar-related species, glycolaldehyde, has been detected in Sgr B2(N), as have its C2H4O2 structural isomers acetic acid and methyl formate. Additional studies of the C3-sugars with empirical formula C3H6O3, glyceraldehyde and dihydroxyacetone, resulted in no clear interstellar detection. Structural isomerism is extensive in interstellar clouds, and there is a high level of correlation between the relative energies of isomers and their relative abundances, with the lowest energy isomers detected in greatest abundance. The detected members of the C2H4O2 family, however, defy this trend, having relative abundances of (acetic acid):(glycolaldehyde):(methyl formate) of about 2:1:52, despite acetic acid being the lowest energy isomer. These puzzling abundance ratios and the lack of detection of the C3H6O3 sugars gives rise to the question: "Which is the most likely isomer in the C3H6O3 family to be detectable in inter- stellar clouds?" In an attempt to answer this question, we carried out geometry optimization calculations to determine the relative binding energies of the 13 members of the C3H6O3 family. Of the four lowest- energy isomers, only lactic acid [CH3CH(OH)COOH] and dimethyl carbonate [(CH3)2CO3] are commercially available, and lactic acid has been previously investigated spectroscopically. We have therefore conducted a laboratory study of dimethyl carbonate, measuring its rotational spectrum from 8.4 - 25.3 GHz using a Fourier-Transform microwave spectrometer, and from 227 - 350 GHz using a direct absorption spectrometer. We report on the theoretical calculations performed on the C3H6O3 family of isomers, the experimental studies of cis-cis dimethyl carbonate, and the implica- tions of these results for interstellar chemistry. The details of this work are also reported in Lovas et

  14. Phosphorus doping of 4H SiC by liquid immersion excimer laser irradiation

    SciTech Connect

    Ikeda, Akihiro; Nishi, Koji; Ikenoue, Hiroshi; Asano, Tanemasa

    2013-02-04

    Phosphorus doping of 4H SiC is performed by KrF excimer laser irradiation of 4H SiC immersed in phosphoric acid. Phosphorus is incorporated to a depth of a few tens of nanometers at a concentration of over 10{sup 20}/cm{sup 3} without generating significant crystal defects. Formation of a pn junction diode with an ideality factor of 1.06 is demonstrated.

  15. Ferromagnetism in proton irradiated 4H-SiC single crystal

    SciTech Connect

    Zhou, Ren-Wei; Wang, Hua-Jie; Chen, Wei-Bin; Li, Fei; Liu, Xue-Chao Zhuo, Shi-Yi; Shi, Er-Wei

    2015-04-15

    Room-temperature ferromagnetism is observed in proton irradiated 4H-SiC single crystal. An initial increase in proton dose leads to pronounced ferromagnetism, accompanying with obvious increase in vacancy concentration. Further increase in irradiation dose lowers the saturation magnetization with the decrease in total vacancy defects due to the defects recombination. It is found that divacancies are the mainly defects in proton irradiated 4H-SiC and responsible for the observed ferromagnetism.

  16. Theoretical study of the bonding of Nb(2+) to CH2, C2H2, and C2H4

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Partridge, Harry

    1991-01-01

    The bonding of Nb(2+) with CH2, C2H2, and C2H4 is studied by using electronic structure calculations that include high levels of electron correlation. The binding energy for NbCH2(2+) is in good agreement with the lower bound determined from the reaction with CH4 but is significantly smaller than the value determined from the binding energy and ionization potential of NbCH2(+). The calculations and a new interpretation of the experiment indicate that the larger value is in error primarily because the ionization potential of NbCH2(+) determined from bracketing charge-exchange reactions is too small. The computed binding energy of NbC2H2(2+) is in good agreement with experiment. The calculations show that the bonding is predominantly covalent in character for both NbCH2(2+) and NbC2H2(2+), whereas for NbC2H4(2+) the electronic states that are predominantly ionic and covalent are nearly degenerate. The trend in binding energies, CH2 greater than C2H2 greater than C2H4, is consistent with the energy required to prepare the ligands for bonding.

  17. Fabrication of High-Q Nanobeam Photonic Crystals in Epitaxially Grown 4H-SiC.

    PubMed

    Bracher, David O; Hu, Evelyn L

    2015-09-01

    Silicon carbide (SiC) is an intriguing material due to the presence of spin-active point defects in several polytypes, including 4H-SiC. For many quantum information and sensing applications involving such point defects, it is important to couple their emission to high quality optical cavities. Here we present the fabrication of 1D nanobeam photonic crystal cavities (PCC) in 4H-SiC using a dopant-selective etch to undercut a homoepitaxially grown epilayer of p-type 4H-SiC. These are the first PCCs demonstrated in 4H-SiC and show high quality factors (Q) of up to ∼7000 as well as low modal volumes of <0.5 (λ/n)(3). We take advantage of the high device yield of this fabrication method to characterize hundreds of devices and determine which PCC geometries are optimal. Additionally, we demonstrate two methods to tune the resonant wavelengths of the PCCs over 5 nm without significant degradation of the Q. Lastly, we characterize nanobeam PCCs coupled to luminescence from silicon vacancy point defects (V1, V2) in 4H-SiC. The fundamental modes of two such PCCs are tuned into spectral overlap with the zero phonon line (ZPL) of the V2 center, resulting in an intensity increase of up to 3-fold. These results are important steps on the path to developing 4H-SiC as a platform for quantum information and sensing. PMID:26305122

  18. Key contribution of eIF4H-mediated translational control in tumor promotion

    PubMed Central

    Vaysse, Charlotte; Philippe, Céline; Martineau, Yvan; Quelen, Cathy; Hieblot, Corinne; Renaud, Claire; Nicaise, Yvan; Desquesnes, Aurore; Pannese, Maria; Filleron, Thomas; Escourrou, Ghislaine; Lawson, Malcolm; Rintoul, Robert C.; Delisle, Marie Bernadette; Pyronnet, Stéphane; Brousset, Pierre; Prats, Hervé; Touriol, Christian

    2015-01-01

    Dysregulated expression of translation initiation factors has been associated with carcinogenesis, but underlying mechanisms remains to be fully understood. Here we show that eIF4H (eukaryotic translation initiation factor 4H), an activator of the RNA helicase eIF4A, is overexpressed in lung carcinomas and predictive of response to chemotherapy. In lung cancer cells, depletion of eIF4H enhances sensitization to chemotherapy, decreases cell migration and inhibits tumor growth in vivo, in association with reduced translation of mRNA encoding cell-proliferation (c-Myc, cyclin D1) angiogenic (FGF-2) and anti-apoptotic factors (CIAP-1, BCL-xL). Conversely, each isoform of eIF4H acts as an oncogene in NIH3T3 cells by stimulating transformation, invasion, tumor growth and resistance to drug-induced apoptosis together with increased translation of IRES-containing or structured 5′UTR mRNAs. These results demonstrate that eIF4H plays a crucial role in translational control and can promote cellular transformation by preferentially regulating the translation of potent growth and survival factor mRNAs, indicating that eIF4H is a promising new molecular target for cancer therapy. PMID:26498689

  19. Association analysis of the LTA4H gene polymorphisms and pulmonary tuberculosis in 9115 subjects

    PubMed Central

    Curtis, James; Kopanitsa, Liliya; Stebbings, Emma; Speirs, Arran; Ignatyeva, Olga; Balabanova, Yanina; Nikolayevskyy, Vladyslav; Hoffner, Sven; Horstmann, Rolf; Drobniewski, Francis; Nejentsev, Sergey

    2011-01-01

    Summary Immunoregulatory eicosanoids have been implicated in protection from mycobacterial infection in cell and animal models. Recently, a study of the zebrafish embryo demonstrated that mutants of the lta4h gene, which encodes the leukotriene A4 hydrolase (LTA4H) enzyme of the eicosanoid pathway, have hypersusceptibility to Mycobacterium marinum infection. It also reported that heterozygosity at the two single nucleotide polymorphisms rs1978331 and rs2660898 located in introns of the LTA4H gene, a human homologue of lta4h, is associated with protection from pulmonary tuberculosis. To replicate this association we genotyped six LTA4H gene polymorphisms in samples from 3703 pulmonary tuberculosis patients and 5412 healthy controls collected in Russia. We found no evidence of the protective effect of heterozygosity at the polymorphisms rs1978331 and rs2660898 (P = 0.29 and 0.49) and no association of the alleles of any of the six polymorphisms (P = 0.13–0.81). These results suggest that common polymorphisms in the LTA4H gene do not play any major role in susceptibility to clinical pulmonary tuberculosis. PMID:21112816

  20. Sandwich SrTiO3/TiO2/H-Titanate nanofiber composite photocatalysts for efficient photocatalytic hydrogen evolution

    NASA Astrophysics Data System (ADS)

    Liu, Yuanxu; Wang, Zhonglei; Wang, Wendong; An, Xiaoqiang; Mi, Shiyang; Tang, Junwang; Huang, Weixin

    2014-10-01

    SrTiO3/TiO2/H-Titanate nanofiber composites were synthesized through facile thermal treatment of Sr(OH)2 and H-titanate nanofibers in an ethanol/water solution and their photocatalytic activities for H2 evolution from a methanol/water solution under simulated solar irradiation were evaluated. TiO2/H-titanate nanofiber composites were acquired without Sr(OH)2 addition. At low Sr/Ti molar ratios, SrTiO3/TiO2/H-titanate nanofiber composites form. SrTiO3 nanoparticles were found to selectively grow on the surface of TiO2 nanoparticles, forming a unique SrTiO3-TiO2-H-titanate sandwich heterojunction. Upon increasing the Sr/Ti molar ratio, the fraction of TiO2 in the resultant composites decreases and eventually SrTiO3/H-titanate nanofiber composites form. SrTiO3/TiO2/H-titanate nanofiber composites are significantly more photocatalytically active than SrTiO3/H-titanate nanofiber and TiO2/H-titanate nanofiber composites due to the mitigated charge recombination and the accumulation of photo-excited electrons on the photocatalytically active TiO2 component. These results demonstrate an effective strategy of multi-heterojunctions with both appropriately-aligned band structures and appropriately-arranged composite structures to fabricate efficient composite photocatalysts.

  1. Ligand-enabled cross-coupling of C(sp3)-H bonds with arylboron reagents via Pd(II)/Pd(0) catalysis

    NASA Astrophysics Data System (ADS)

    Chan, Kelvin S. L.; Wasa, Masayuki; Chu, Ling; Laforteza, Brian N.; Miura, Masanori; Yu, Jin-Quan

    2014-02-01

    There have been numerous developments in C-H activation reactions in the past decade. Attracted by the ability to functionalize molecules directly at ostensibly unreactive C-H bonds, chemists have discovered reaction conditions that enable reactions of C(sp2)-H and C(sp3)-H bonds with a variety of coupling partners. Despite these advances, the development of suitable ligands that enable catalytic C(sp3)-H bond functionalization remains a significant challenge. Herein we report the discovery of a mono-N-protected amino acid ligand that enables Pd(II)-catalysed coupling of γ-C(sp3)-H bonds in triflyl-protected amines with arylboron reagents. Remarkably, no background reaction was observed in the absence of ligand. A variety of amine substrates and arylboron reagents were cross-coupled using this method. Arylation of optically active substrates derived from amino acids also provides a potential route for preparing non-proteinogenic amino acids.

  2. A two-fold interpenetrating 3D metal-organic framework material constructed from helical chains linked via 4,4'-H{sub 2}bpz fragments

    SciTech Connect

    Xie Yiming; Zhao Zhenguo; Wu Xiaoyuan; Zhang Qisheng; Chen Lijuan; Wang Fei; Chen Shanci; Lu Canzhong

    2008-12-15

    A 3-connected dia-f-type metal-organic framework compound {l_brace}[Ag(L){sub 3/2}H{sub 2}PO{sub 4}]{r_brace}{sub n} (1) has been synthesized by self-assembly of 4,4'-H{sub 2}bpz (L=4,4'-H{sub 2}bpz=3,3',5,5'-tetramethyl-4,4'-bipyrazole) and Ag{sub 4}P{sub 2}O{sub 7} under hydrothermal conditions. It crystallizes in the tetragonal space group I4{sub 1}/acd with a=21.406(4) A, b=21.406(4) A, c=36.298(8) A, Z=32. X-ray single-crystal diffraction reveals that 1 has a three-dimensional framework with an unprecedented alternate left- and right-handed helices structure, featuring a non-uniform two-fold interpenetrated (4.14{sup 2}) net. Photoluminescent investigation reveals that the title compound displays interesting emissions in a wide region, which shows that the title compound may be a good potential candidate as a photoelectric material. - Graphical abstract: A 3-connected dia-f-type metal-organic framework compound [Ag(4,4'-bpz){sub 3/2}H{sub 2}PO{sub 4}] shows unprecedented alternating left- and right-handed helices structure, featuring a non-uniform two-fold interpenetrated (4.14{sup 2}) net.

  3. Detection of the Elusive Triazane Molecule (N3 H5 ) in the Gas Phase.

    PubMed

    Förstel, Marko; Maksyutenko, Pavlo; Jones, Brant M; Sun, Bing-Jian; Chen, Shih-Hua; Chang, Agnes H-H; Kaiser, Ralf I

    2015-10-26

    We report the detection of triazane (N3 H5 ) in the gas phase. Triazane is a higher order nitrogen hydride of ammonia (NH3 ) and hydrazine (N2 H4 ) of fundamental importance for the understanding of the stability of single-bonded chains of nitrogen atoms and a potential key intermediate in hydrogen-nitrogen chemistry. The experimental results along with electronic-structure calculations reveal that triazane presents a stable molecule with a nitrogen-nitrogen bond length that is a few picometers shorter than that of hydrazine and has a lifetime exceeding 6±2 μs at a sublimation temperature of 170 K. Triazane was synthesized through irradiation of ammonia ice with energetic electrons and was detected in the gas phase upon sublimation of the ice through soft vacuum ultraviolet (VUV) photoionization coupled with a reflectron-time-of-flight mass spectrometer. Isotopic substitution experiments exploiting [D3 ]-ammonia ice confirmed the identification through the detection of its fully deuterated counterpart [D5 ]-triazane (N3 D5 ). PMID:26331382

  4. Hydride transfer reaction dynamics of OD{sup +}+C{sub 3}H{sub 6}

    SciTech Connect

    Liu, Li; Richards, Elizabeth S.; Farrar, James M.

    2007-06-28

    The hydride transfer reaction between OD{sup +} and C{sub 3}H{sub 6} has been studied experimentally and theoretically over the center of mass collision energy range from 0.21 to 0.92 eV using the crossed beam technique and density functional theory calculations. The center of mass flux distributions of the product ions at three different energies are highly asymmetric, with maxima close to the velocity and direction of the precursor propylene beam, characteristic of direct reactions. In the hydride transfer process, the entire reaction exothermicity is transformed into product internal excitation, consistent with mixed energy release in which the hydride ion is transferred with both the breaking and forming bonds extended. At higher collision energies, at least 85% of the incremental translational energy appears in product translation, providing a clear example of induced repulsive energy release. Compared to the related reaction of OD{sup +} with C{sub 2}H{sub 4}, reaction along the pathway initiated by addition of OD{sup +} to the C=C bond in propylene has a critical bottleneck caused by the torsional motion of the methyl substituent on the double bond. This bottleneck suppresses reaction through an intermediate complex in favor of direct hydride abstraction. Hydride abstraction appears to be a sequential process initiated by electron transfer in the triplet manifold, followed by rapid intersystem crossing and subsequent hydrogen atom transfer to form ground state allyl cation and HOD.

  5. Preservation of "peripheral" benzodiazepine receptors: differential effects of freezing on [3H]Ro 5-4864 and [3H]PK 11195 binding.

    PubMed

    Basile, A S; Skolnick, P

    1987-04-01

    The equilibrium binding constants of [3H]Ro 5-4864 (a "peripheral" benzodiazepine receptor ligand) to renal membranes preserved by various freezing techniques were investigated. The Bmax for [3H]Ro 5-4864 binding to membranes from kidneys preserved as unwashed homogenates stored at -80, -20, or 5 degrees C, whole kidneys stores at -20 or 5 degrees C or as washed homogenate stored at -20 degrees C was significantly decreased (approximately 35%). Only when kidneys were frozen intact (using a dry-ice/acetone slurry) and stored at -80 degrees C was the density of [3H]Ro 5-4864 binding unchanged. However, the Bmax of [3H]PK 11195 (a putative "peripheral" benzodiazepine receptor antagonist) binding to renal membranes was unchanged following storage techniques that reduced the density of [3H]Ro 5-4864 binding 38%. No change was observed in the Kd values for [3H]Ro 5-4864 and [3H]PK 11195 binding to renal membranes preserved under any condition tested. These results demonstrate a method for the preservation of [3H]Ro 5-4864 binding to renal membranes, and suggests that [3H]Ro 5-4864 and [3H]PK 11195 bind to unique sites on or near the "peripheral" benzodiazepine receptor. [corrected] PMID:3035290

  6. C2H observations toward the Orion Bar

    NASA Astrophysics Data System (ADS)

    Nagy, Z.; Ossenkopf, V.; Van der Tak, F. F. S.; Faure, A.; Makai, Z.; Bergin, E. A.

    2015-06-01

    Context. The ethynyl radical (C2H) is one of the first radicals to be detected in the interstellar medium. Its higher rotational transitions have recently become available with the Herschel Space Observatory. Aims: We aim to constrain the physical parameters of the C2H emitting gas toward the Orion Bar. Methods: We analyze the C2H line intensities measured toward the Orion Bar CO+ Peak and Herschel/HIFI maps of C2H, CH, and HCO+ and a NANTEN map of [Ci]. We interpret the observed C2H emission using the combination of Herschel/HIFI and NANTEN data with radiative transfer and PDR models. Results: Five rotational transitions of C2H (from N = 6-5 up to N = 10-9) have been detected in the HIFI frequency range toward the CO+ peak of the Orion Bar. Based on the five detected C2H transitions, a single component rotational diagram analysis gives a rotation temperature of ~64 K and a beam-averaged C2H column density of 4 × 1013 cm-2. The rotational diagram is also consistent with a two-component fit, resulting in rotation temperatures of 43 ± 0.2 K and 123 ± 21 K and in beam-averaged column densities of ~8.3 × 1013 cm-2 and ~2.3 × 1013 cm-2 for the three lower-N and for the three higher-N transitions, respectively. The measured five rotational transitions cannot be explained by any single parameter model. According to a non-LTE model, most of the C2H column density produces the lower-N C2H transitions and traces a warm (Tkin ~ 100-150 K) and dense (n(H2) ~ 105-106 cm-3) gas. A small fraction of the C2H column density is required to reproduce the intensity of the highest-N transitions (N = 9-8 and N = 10-9) originating in a high-density (n(H2) ~5 × 106 cm-3) hot (Tkin ~ 400 K) gas. The total beam-averaged C2H column density in the model is 1014 cm-2. A comparison of the spatial distribution of C2H to those of CH, HCO+, and [Ci] shows the best correlation with CH. Conclusions: Both the non-LTE radiative transfer model and a simple PDR model representing the Orion Bar

  7. Alpha-adrenoceptors in dog mesenteric vessels--subcellular distribution and number of ( sup 3 H)prazosin and ( sup 3 H)rauwolscine binding sites

    SciTech Connect

    Shi, A.G.; Ahmad, S.; Kwan, C.Y.; Daniel, E.E. )

    1990-04-01

    Binding of the alpha-adrenergic antagonists ({sup 3}H)prazosin and ({sup 3}H)rauwolscine to well-characterized subcellular membrane fractions isolated from dog mesenteric arteries and veins was studied. Binding of both ligands was saturable with Kd values of 0.5 +/- 0.1 nM for ({sup 3}H)prazosin and 5.85 +/- 0.85 nM for ({sup 3}H)rauwolscine in arteries, and 0.87 +/- 0.4 nM for ({sup 3}H)prazosin and 6.6 +/- 1.5 nM for ({sup 3}H)rauwolscine in veins. In veins, the maximum number of binding sites for ({sup 3}H)rauwolscine was higher than that for ({sup 3}H)prazosin, whereas in arteries the maximum number of binding sites for each ligand was similar. In microsomes from dog aorta, the maximum number of bindings sites for ({sup 3}H)prazosin was higher than that for ({sup 3}H)rauwolscine. Neuronal membrane contamination in these studies was minimized by dissection procedures and evaluated by the comparison of ({sup 3}H)saxitoxin binding in various preparations. Only mesenteric veins responded functionally to agonists acting on alpha 2 adrenoceptors. This study thus identified two distinct populations of ({sup 3}H)prazosin and ({sup 3}H)rauwolscine binding sites in the plasma membranes of dog mesenteric vessels and suggests that a much higher density of alpha 2-compared to alpha 1-adrenoceptor binding sites is required for a contractile response.

  8. Uptake and metabolism of (/sup 3/H)testosterone in the brain, pituitary gland and genital tract of the male cynomolgus monkey

    SciTech Connect

    Bonsall, R.W.; Rees, H.D.; Micheal, R.P.

    1986-03-01

    To study the mechanism by which testosterone restores the sexual potency of castrated cynomolgus monkeys, two males (body weights 5.2 and 5.3 kg) were castrated and, 3 days later, injected with 3 mCi (/sup 3/H)testosterone ((/sup 3/H)T) as an intravenous bolus. After 30 min, males were killed and brains and samples of other tissues were rapidly removed and placed on ice. Samples were dissected from the right halves of the brain and homogenized. Purified cell nuclei were prepared and ether extracts were analyzed by reverse-phase HPCL. Generally, unchanged (/sup 3/H)T was the major form of radioactivity in brain and pituitary gland, but in cell nuclei from hypothalamus, preoptic area and amygdala, a large proportion (34 - 61%) was in the form of (/sup 3/H)estradiol ((/sup 4/H)E/sub 2/). Little or no (/sup 3/H)dihydrotestosterone ((/sup 3/H)DHT) was detected in cell nuclei from any brain region or from pituitary gland. However, (/sup 3/H)DHT was the major form (61 - 95%) of radioactivity in cell nuclei from glans penis, prostrate and seminal vesicles. In autoradiograms of the left halves of the same brains, the percentage of cells that accumulated radioactivity in their nuclei was high in specific regions of the hypothalamus, preoptic areas and amygdala. The authors conclude that the peripheral actions of T are mediated via DHT, but its central actions are dependent on unchanged T or on E/sub 2/ formed locally by aromatization.

  9. In vivo labeling of cocaine receptors with sup 3 H-(-) cocaine, sup 3 H-WIN 35,065-2 and sup 3 H-WIN 35,428

    SciTech Connect

    Scheffel, U.; Boja, J.W.; Stathis, M.; Kuhar, M.J. )

    1990-02-26

    {sup 11}C-(-)cocaine (-COC) has recently been employed to image -COC binding sites in vivo using PET. Two analogs of -COC, WIN 35,065-2 (WIN-2) and WIN 35,428 (CFT), have been shown in vitro to exhibit higher affinity for the -COC receptor than -COC. The present study evaluates {sup 3}H-WIN-2 and {sup 3}H-CFT as in vivo receptor labels in mice with a view towards the use of these compounds as PET ligands for -COC receptors in the living human brain. {sup 3}H-labeled -COC, WIN-2 and CFT were injected i.v. into mice and their specific binding in the CNS determined. Peak striatal/cerebellar (S/C) ratios were reached at 5 minutes post injection with -COC (1.56), at 45 minutes with {sup 3}H-WIN-2 (3.30) and 60 minutes with {sup 3}H-CFT (4.0). The specificity of in vivo binding of {sup 3}H-WIN-2 and {sup 3}H-CFT was tested by pre-injection of various drugs. Binding of {sup 3}H-WIN-2 and {sup 3}H-CFT was dose-dependently blocked by cold WIN-2 and CFT, and by dopamine uptake site inhibitors (mazindol, GBR 12,909, nomifensine), but not by (+)COC, paroxetine and desipramine. The data indicate that {sup 3}H-WIN-2 and {sup 3}H-CFT exhibit improved in vivo binding (higher S/C ratios, longer retention time at the -COC receptor/dopamine transporter) compared to -COC and support their testing in PET studies.

  10. Oxalic acid mediated synthesis of WO{sub 3}.H{sub 2}O nanoplates and self-assembled nanoflowers under mild conditions

    SciTech Connect

    Li Linzhi; Zhao Jingzhe; Wang Yi; Li Yunling; Ma Dechong; Zhao Yan; Hou Shengnan; Hao Xinli

    2011-07-15

    Tungsten oxide hydrate (WO{sub 3}.H{sub 2}O) nanoplates and flower-like assemblies were successfully synthesized via a simple aqueous method. The effects of reaction parameters in solution on the preparation were studied. Nanoplates and nanoflowers can be selectively prepared by changing the amount of H{sub 2}C{sub 2}O{sub 4}. In-situ assembly of nanoplates to nanoflowers was also proposed for the formation of assembled nanostructures. In addition, the reaction time and temperature have important effects on the sizes of the as-obtained samples. Crystal structure, morphology, and composition of final nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties of the synthesized samples and the growth mechanism were studied by UV-vis detection. Degradation experiments of Rhodamine B (RhB) were also performed on samples of nanoplates and nanoflowers under visible light illumination. Nanoflower sample exhibited preferable photocatalytic property to nanoplate sample. - Graphical abstract: The oxalic acid has a key role for the structure of WO{sub 3}.H{sub 2}O evolution from plates to flowers and the dehydration process of WO{sub 3}.2H{sub 2}O to WO{sub 3}.H{sub 2}O. Highlights: > Tungsten oxides hydrate was synthesized via a simple aqueous method. > The size of WO{sub 3}.H{sub 2}O was controlled by the reaction time and temperature. > The assembly of WO{sub 3}.H{sub 2}O nanoplates to nanoflowers was achieved with higher H{sub 2}C{sub 2}O{sub 4}/Na{sub 2}WO{sub 4} ratio. > Oxalic acid has a key role in the dehydration process of WO{sub 3}.2H{sub 2}O to WO{sub 3}.H{sub 2}O.

  11. Binding of dexetimide and levetimide to [3H](+)pentazocine- and [3H]1,3-di(2-tolyl)guanidine-defined sigma recognition sites.

    PubMed

    DeHaven-Hudkins, D L; Hudkins, R L

    1991-01-01

    The potent antimuscarinic benzetimide and its resolved stereoisomers dexetimide and levetimide were tested for their affinities at sigma sites labelled by [3H](+)pentazocine or [3H]1,3-di(2-tolyl)guanidine. Levetimide was a potent and stereoselective inhibitor of [3H](+)pentazocine binding, with a Ki of 2.2 nM, while dexetimide was nine-fold less potent (Ki = 19 nM). Dexetimide and levetimide potently inhibited [3H]DTG binding although without stereoselectivity (Ki values of 65 and 103 nM, respectively). Levetimide may be a useful tool with which to investigate sigma recognition sites and sigma subtypes. PMID:1656155

  12. Ethanol intake and sup 3 H-serotonin uptake II: A study in alcoholic patients using platelets sup 3 H-paroxetine binding

    SciTech Connect

    Daoust, M.; Boucly, P. ); Ernouf, D. ); Breton, P. ); Lhuintre, J.P.

    1991-01-01

    The kinetic parameters of {sup 3}H-paroxetine binding and {sup 3}H-serotonin uptake were studied in platelets of alcoholic patients. There was no difference between alcoholic and non alcoholic subjects in {sup 3}H-paroxetine binding. When binding and {sup 3}H-serotonin uptake were studied, in the same plasma of the same subjects, the Vmax of serotonin uptake was increased in alcoholics. The data confirm the involvement of serotonin uptake system in alcohol dependance and suggest that serotonin uptake and paroxetine binding sites may be regulated independently in this pathology.

  13. CVD Growth of 3C-SiC on 4H/6H Mesas

    SciTech Connect

    Neudeck,P.; Trunek, A.; Spry, D.; Powell, J.; Du, H.; Skowronski, M.; Huang, X.; Dudley, M.

    2006-01-01

    This article describes growth and characterization of the highest quality reproducible 3C-SiC heteroepitaxial films ever reported. By properly nucleating 3C-SiC growth on top of perfectly on-axis (0001) 4H-SiC mesa surfaces completely free of atomic scale steps and extended defects, growth of 3C-SiC mesa heterofilms completely free of extended crystal defects can be achieved. In contrast, nucleation and growth of 3C-SiC mesa heterofilms on top of 4H-SiC mesas with atomic-scale steps always results in numerous observable dislocations threading through the 3C-SiC epilayer. High-resolution X-ray diffraction (HRXRD) and high resolution cross-sectional transmission electron microscopy (HRXTEM) measurements indicate non-trivial, in-plane, lattice mismatch between the 3C and 4H layers. This mismatch is somewhat relieved in the step-free mesa case via misfit dislocations confined to the 3C/4H interfacial region without dislocations threading into the overlying 3C-SiC layer. These results indicate that the presence or absence of steps at the 3C/4H heteroepitaxial interface critically impacts the quality, defect structure, and relaxation mechanisms of single-crystal heteroepitaxial 3C-SiC films.

  14. Disruption of PF4/H multimolecular complex formation with a minimally anticoagulant heparin (ODSH)

    PubMed Central

    Joglekar, Manali V.; Quintana Diez, Pedro M.; Marcus, Stephen; Qi, Rui; Espinasse, Benjamin; Wiesner, Mark R.; Pempe, Elizabeth; Liu, Jian; Monroe, Dougald M.; Arepally, Gowthami M.

    2015-01-01

    Summary Recent studies have shown that ultra-large complexes (ULCs) of platelet factor 4 (PF4) and heparin (H) play an essential role in the pathogenesis of Heparin-Induced Thrombocytopenia (HIT), an immune-mediated disorder caused by PF4/H antibodies. Because antigenic PF4/H ULCs assemble through non-specific electrostatic interactions, we reasoned that disruption of charge-based interactions can modulate the immune response to antigen. We tested a minimally anticoagulant compound (2-O, 3-O desulfated heparin or ODSH) with preserved charge to disrupt PF4/H complex formation and immunogenicity. We show that ODSH disrupts complexes when added to pre-formed PF4/H ULCs and prevents ULC formation when incubated simultaneously with PF4 and UFH. In other studies, we show that excess ODSH reduces HIT antibody (Ab) binding in immunoassays and that PF4/ODSH complexes do not cross-react with HIT Abs. When ODSH and UFH are mixed at equimolar concentrations, we show that there is a negligible effect on amount of protamine required for heparin neutralization and reduced immunogenicity of PF4/UFH in the presence of ODSH. Taken together, these studies suggest that ODSH can be used concurrently with UFH to disrupt PF4/H charge interactions and provides a novel strategy to reduce antibody mediated complications in HIT. PMID:22318669

  15. Existence of {sub {lambda}}{sub {lambda}}{sup 4}H: A variational Monte Carlo search

    SciTech Connect

    Shoeb, Mohammad

    2005-02-01

    A variational Monte Carlo (VMC) calculation for the binding energy B{sub {lambda}}{sub {lambda}} of the lightest hypernucleus {sub {lambda}}{sub {lambda}}{sup 4}H has been performed in the four-body {lambda}{lambda}pn model. A range of input {lambda}{lambda} potentials of moderate strength produce a particle-stable {sub {lambda}}{sub {lambda}}{sup 4}H for the simulated NSC97e and f {lambda}N potentials, whereas the phenomenological Minnesota {lambda}N potential needs a much stronger {lambda}{lambda} potential to bind. The VMC results for B{sub {lambda}}{sub {lambda}} agree with the prediction of the stochastic variational model but contradict the recent Faddeev-Yakubovsky calculation. As reported earlier, B{sub {lambda}}{sub {lambda}} is sensitive to the triplet {lambda}N channel for a given {lambda}{lambda} potential. The B{sub {lambda}}{sub {lambda}} of {sub {lambda}}{sub {lambda}}{sup 4}H in the three-body {lambda}{lambda}d cluster model is consistent with but slightly lower than the Faddeev calculation. The VMC method predicts a stable {sub {lambda}}{sub {lambda}}{sup 4}H system in both models and thus offers the possibility of identifying {sub {lambda}}{sub {lambda}}{sup 4}H in a future extension of E906 or of a related experiment at KEK, provided the simulated potentials are true representations of realistic Nijmegen potentials.

  16. Self-assembly of C4H-type hydrogenated graphene.

    PubMed

    Liu, Zilong; Xue, Qingzhong; Xing, Wei; Du, Yonggang; Han, Zhide

    2013-11-21

    We demonstrate by molecular dynamic (MD) simulations that patterned partially hydrogenated graphene (C4H) can self-assemble at room temperature. The main driving force of the self-assembly of C4H is due to the one-sided distribution of hydrogen and the corresponding asymmetric orientation of sp(3) bonding, there exists strong electrostatic repulsion between the relatively close H atoms. The simulations show that C4H can self-assemble into various carbon nanoscroll (CNS) structures, this is mainly controlled by its geometry (size and aspect ratio). And the carbon nanotube (CNT) is a good candidate to activate and guide C4H to form CNS, whose core size can be controlled. Meanwhile, a novel CNT/C4H core/shell composite nanostructure is also formed. The theoretical results shed important light on a feasible approach to fabricate high-quality CNS and other novel nanostructures including core/shell structures, which hold great potential applications in optics, optoelectronic devices, hydrogen storage, sensors, and energy storage in supercapacitors or batteries. PMID:24064528

  17. CFD Growth of 3C-SiC on 4H/6H Mesas

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Trunek, Andrew J.; Spry, David J.; Powell, J. Anthony; Du, Hui; Skowronski, Marek; Huang, XianRong; Dudley, Michael

    2006-01-01

    This article describes growth and characterization of the highest quality reproducible 3C-SiC heteroepitaxial films ever reported. By properly nucleating 3C-SiC growth on top of perfectly on-axis (0001) 4H-SiC mesa surfaces completely free of atomic scale steps and extended defects, growth of 3C-SiC mesa heterofilms completely free of extended crystal defects can be achieved. In contrast, nucleation and growth of 3C-SiC mesa heterofilms on top of 4H-SiC mesas with atomic-scale steps always results in numerous observable dislocations threading through the 3C-SiC epilayer. High-resolution X-ray diffraction and transmission electron microscopy measurements indicate non-trivial in-plane lattice mismatch between the 3C and 4H layers. This mismatch is somewhat relieved in the step-free mesa case via misfit dislocations confined to the 3C/4H interfacial region without dislocations threading into the overlying 3C-SiC layer. These results indicate that the presence or absence of steps at the 3C/4H heteroepitaxial interface critically impacts the quality, defect structure, and relaxation mechanisms of single-crystal heteroepitaxial 3C-SiC films.

  18. Meridional Variations of C2H2 and C2H6 in Jupiter's Atmosphere from Cassini CIRS Infrared Spectra

    NASA Technical Reports Server (NTRS)

    Nixon, C. A.; Achterberg, R. K.; Conrath, B. J.; Irwin, P. G. J.; Fouchet, T.; Parrish, P. D.; Romani, P. N.; Abbas, M.; LeClair, A.; Strobel, D.

    2004-01-01

    Hydrocarbons such as acetylene (C2H2) and ethane (C2H6) are important tracers in Jupiter's atmosphere, constraining our models of the chemical and dynamical processes. However, our knowledge of the vertical and meridional variations of their abundances has remained sparse. During the flyby of the Cassini spacecraft in December 2000, the Composite Infrared Spectrometer (CIRS) instrument was used to map the spatial variation of emissions from 10-1400 cm(sup -1) (1000-7 microns). In this paper we analyze a zonally-averaged set of CIRS spectra taken at the highest (0.5 cm(sup -1)) resolution, to infer atmospheric temperatures in the stratosphere at 0.5-20 mbar via the v4 band of CH4, and in the troposphere at 150-400 mbar, via the H2 absorption at 600-800 cm(sup -1). Simultaneously, we retrieve the abundances of C2H2 and C2H6 via the v5 and vg bands respectively. Tropospheric absorption and stratospheric emission are highly anti-correlated at the CIRS resolution, introducing a non-uniqueness into the retrievals, such that vertical gradient and column abundance cannot both be found without additional constraints. Assuming profile gradients from photochemical calculations, we show that the column abundance of C2H2 decreases sharply towards the poles by a factor approximately 4, while C2H6 is unchanged in the north and increasing in the south, by a factor approximately 1.8. An explanation for the meridional trends is proposed in terms of a combination of photochemistry and dynamics. Poleward, the decreasing UV flux is predicted to decrease the abundances of C2H2 and C2H6 by factors 2.7 and 3.5 respectively at a latitude 70 deg. However, the lifetime of C2H6 in the stratosphere (5 x 10(exp 9)) is much longer than the dynamical timescale for meridional motions inferred from SL-9 debris (5 x 10(exp 8 s)), and therefore the constant or rising abundance towards high latitudes likely indicates that meridional mixing dominates over photochemical effects. For C2H2, the opposite

  19. The lta4h Locus Modulates Susceptibility to Mycobacterial Infection in Zebrafish and Humans

    PubMed Central

    Tobin, David M.; Vary, Jay C.; Ray, John P.; Walsh, Gregory S.; Dunstan, Sarah J.; Bang, Nguyen D.; Hagge, Deanna A.; Khadge, Saraswoti; King, Mary-Claire; Hawn, Thomas R.; Moens, Cecilia B.; Ramakrishnan, Lalita

    2010-01-01

    SUMMARY Exposure to Mycobacterium tuberculosis produces varied early outcomes, ranging from resistance to infection to progressive disease. Here we report results from a forward genetic screen in zebrafish larvae that identify multiple mutant classes with distinct patterns of innate susceptibility to Mycobacterium marinum. A hypersusceptible mutant maps to the lta4h locus encoding leukotriene A4 hydrolase, which catalyzes the final step in the synthesis of leukotriene B4 (LTB4), a potent chemoattractant and proinflammatory eicosanoid. lta4h mutations confer hypersusceptibility independent of LTB4 reduction, by redirecting eicosanoid substrates to anti-inflammatory lipoxins. The resultant anti-inflammatory state permits increased mycobacterial proliferation by limiting production of tumor necrosis factor. In humans, we find that protection from both tuberculosis and multibacillary leprosy is associated with heterozygosity for LTA4H polymorphisms that have previously been correlated with differential LTB4 production. Our results suggest conserved roles for balanced eicosanoid production in vertebrate resistance to mycobacterial infection. PMID:20211140

  20. Angiotensin II stimulates /sup 3/H-leucine and /sup 3/H-thymidine incorporation in cultured vascular smooth muscle cells

    SciTech Connect

    Dwyer, S.D.; Smith, J.B.

    1987-05-01

    Angiotensin II (ANG) stimulates the hydrolysis of phosphatidylinositol bisphosphate with the consequent formation of inositol trisphosphate and diacylglycerol in cultured smooth muscle cells derived from rat aorta. They have observed the effects of ANG on protein and DNA synthesis by measuring the incorporation of /sup 3/H-leucine and /sup 3/H-thymidine, respectively, into acid-precipitable material. Aortic muscle cells were grown to confluence in medium containing 10% fetal bovine serum (FBS) and incubated for 24 hours in serum-free medium to arrest growth. Then fresh serum-free medium was added with the following additions: ANG (100 nM), insulin (2 ..mu..g/ml), or 10% FBS. After an additional 24 hours the cells were pulse labeled for 30 min with either /sup 3/H-leucine or /sup 3/H-thymidine. FBS increased /sup 3/H-leucine incorporation by -2.5 fold and /sup 3/H-thymidine incorporation by 7-10 fold. ANG or insulin increased /sup 3/H-leucine incorporation by 40-50%, and the combination of ANG and insulin was nearly as effective as 10% FBS. ANG stimulated /sup 3/H-thymidine incorporation by -2.5 fold. Insulin, which was less effective than ANG, increased /sup 3/H-thymidine incorporation by about 50%. ANG and insulin added together synergistically increased /sup 3/H-thymidine incorporation by 5-6 fold. An ANG antagonist, Sarl,leu8-ANG, at 2 ..mu..M markedly decreased /sup 3/H-thymidine incorporation in the presence of ANG and insulin.

  1. Uptake and metabolism of L-(/sup 3/H)glutamate and L-(/sup 3/H)glutamine in adult rat cerebellar slices

    SciTech Connect

    de Barry, J.; Vincendon, G.; Gombos, G.

    1983-10-01

    Using very low concentrations (1 mumol range) of L-2-3-(/sup 3/H)glutamate, (/sup 3/H-Glu) or L-2-3-(/sup 3/H)glutamine (/sup 3/H-Gln), the authors have previously shown by autoradiography that these amino acids were preferentially taken up in the molecular layer of the cerebellar cortex. Furthermore, the accumulation of /sup 3/H-Glu was essentially glial in these conditions. Uptake and metabolism of either (/sup 3/H-Glu) or (/sup 3/H-Gln) were studied in adult rat cerebellar slices. Both amino acids were rapidly converted into other metabolic compounds: after seven minutes of incubation in the presence of exogenous /sup 3/H-Glu, 70% of the tissue accumulated radioactivity was found to be in compounds other than glutamate. The main metabolites were Gln (42%), alpha-ketoglutarate (25%) and GABA (1,4%). In the presence of exogenous /sup 3/H-Gln the rate of metabolism was slightly slower (50% after seven minutes of incubation) and the metabolites were also Glu (29%), alpha-ketoglutarate (15%) and GABA (5%). Using depolarizing conditions (56 mM KCl) with either exogenous /sup 3/H-Glu or /sup 3/H-Gln, the radioactivity was preferentially accumulated in glutamate compared to control. From these results we conclude: i) there are two cellular compartments for the neurotransmission-glutamate-glutamine cycle; one is glial, the other neuronal; ii) these two cellular compartments contain both Gln and Glu; iii) transmitter glutamate is always in equilibrium with the so-called ''metabolic'' pool of glutamate; iv) the regulation of the glutamate-glutamine cycle occurs at least at two different levels: the uptake of glutamate and the enzymatic activity of the neuronal glutaminase.

  2. DNA Mismatch Repair Interacts with CAF-1- and ASF1A-H3-H4-dependent Histone (H3-H4)2 Tetramer Deposition.

    PubMed

    Rodriges Blanko, Elena; Kadyrova, Lyudmila Y; Kadyrov, Farid A

    2016-04-22

    DNA mismatch repair (MMR) is required for the maintenance of genome stability and protection of humans from several types of cancer. Human MMR occurs in the chromatin environment, but little is known about the interactions between MMR and the chromatin environment. Previous research has suggested that MMR coincides with replication-coupled assembly of the newly synthesized DNA into nucleosomes. The first step in replication-coupled nucleosome assembly is CAF-1-dependent histone (H3-H4)2 tetramer deposition, a process that involves ASF1A-H3-H4 complex. In this work we used reconstituted human systems to investigate interactions between MMR and CAF-1- and ASF1A-H3-H4-dependent histone (H3-H4)2 tetramer deposition. We have found that MutSα inhibits CAF-1- and ASF1A-H3-H4-dependent packaging of a DNA mismatch into a tetrasome. This finding supports the idea that MMR occurs before the DNA mismatch is packaged into the tetrasome. Our experiments have also revealed that CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers does not interfere with MMR reactions. In addition, we have established that unnecessary degradation of the discontinuous strand that takes place in both DNA polymerase δ (Pol δ)- and DNA polymerase ϵ (Pol ϵ)-dependent MMR reactions is suppressed by CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers. These data suggest that CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers is compatible with MMR and protects the discontinuous daughter strand from unnecessary degradation by MMR machinery. PMID:26945061

  3. Temperature dependent product yields for the spin forbidden singlet channel of the C(3P) + C2H2 reaction

    NASA Astrophysics Data System (ADS)

    Hickson, Kevin M.; Loison, Jean-Christophe; Wakelam, Valentine

    2016-08-01

    The atomic hydrogen formation channels of the C + C2H2 reaction have been investigated using a continuous supersonic flow reactor over the 52-296 K temperature range. H-atoms were detected directly at 121.567 nm by vacuum ultraviolet laser induced fluorescence. Absolute H-atom yields were determined by comparison with the H-atom signal generated by the C + C2H4 reaction. The product yields agree with earlier crossed beam experiments employing universal detection methods. Incorporating these branching ratios in a gas-grain model of dense interstellar clouds increases the c-C3H abundance. This reaction is a minor source of C3-containing molecules in the present simulations.

  4. Adult volunteerism in Pennsylvania 4-H natural resources programs for youth

    NASA Astrophysics Data System (ADS)

    Smith, Sanford Sherrick

    2001-07-01

    Pennsylvania's 4-H Youth Development Program relies on adult volunteers to reach youth with educational information and opportunities. Finding adults willing to do this volunteer work is challenging. This study looks at the current status of adult volunteerism with natural resources 4-H projects, and seeks to understand potential volunteers. The literature has much to offer in regards to general volunteer trends, management, motivations, and task preferences; however, few studies focus on volunteers in natural resources or environmental education. A telephone survey conducted with county 4-H agents revealed that only 3.2% of Pennsylvania's 4-H volunteers work with natural resources projects in 56 out of 67 counties, and that very few volunteers have any formal background in natural resources. Semi-structured interviews with 41 adult volunteers currently working with natural resources projects explored volunteer demographics, history, program design preferences, and ideas for seeking more volunteers. Findings from the telephone survey and the semi-structured interviews were used to generate a mail survey with large, random samples from three population groups: (1) 4-H Volunteers, (2) 4-H Parents, and (3) Natural Resources Professionals. Confidence with youth and subject matter, and adult willingness to volunteer was explored for each of the groups in relation to background, demographic characteristics, motivational needs, past and present volunteer activity, personal interests, and program design importance. Natural resources subject matter confidence was shown to be the most significant variable determining willingness to volunteer for all three groups. The variables that contributed to subject matter and youth confidence varied for each population. Key variables effecting willingness to volunteer included outdoor activity level, personal interest in natural resources, the need to fulfill feelings of social responsibility, and confidence with youth. Program design

  5. Synthesis, antifungal activity and docking study of 2-amino-4H-benzochromene-3-carbonitrile derivatives

    NASA Astrophysics Data System (ADS)

    Mirjalili, BiBi Fatemeh; Zamani, Leila; Zomorodian, Kamiar; Khabnadideh, Soghra; Haghighijoo, Zahra; Malakotikhah, Zahra; Ayatollahi Mousavi, Seyyed Amin; Khojasteh, Shaghayegh

    2016-07-01

    Pathogenic fungi are associated with diseases ranging from simple dermatosis to life-threatening infections, particularly in immunocompromised patients. During the past two decades, resistance to established antifungal drugs has increased dramatically and has made it crucial to identify novel antimicrobial compounds. Here, we selected 12 new compounds of 2-amino-4H-benzochromene-3-carbonitrile drivetives (C1-C12) for synthesis by using nano-TiCl4.SiO2 as efficient and green catalyst, then nine of synthetic compounds were evaluated against different species of fungi, positive gram and negative gram of bacteria. Standard and clinical strains of antibiotics sensitive and resistant fungi and bacteria were cultured in appropriate media. Biological activity of the 2-amino-4H-benzochromene-3-carbonitrile derivatives against fungi and bacteries were estimated by the broth micro-dilution method as recommended by clinical and laboratory standard institute (CLSI). In addition minimal fangicidal and bactericial concenteration of the compounds were also determined. Considering our results showed that compound 2-amino-4-(4-methyl benzoate)-4H-benzo[f]chromen-3-carbonitrile (C9) had the most antifungal activity against Aspergillus clavatus, Candida glabarata, Candida dubliniensis, Candida albicans and Candida tropicalis at concentrations ranging from 8 to ≤128 μg/mL. Also compounds 2-amino-4-(3,4-dimethoxyphenyl)-4H-benzo[f]chromen-3-carbonitrile (C4) and 2-amino-4-(4-isopropylphenyl)-4H-benzo[f]chromen-3-carbonitrile (C3) had significant inhibitory activities against Epidermophyton floccosum following 2-amino-4-(4-methylbenzoate)-4H-benzo[f]chromen-3-carbonitrile (C9), respectively. Docking simulation was performed to insert compounds C3, C4 and C9 in to CYP51 active site to determine the probable binding model.

  6. Synthesis, antifungal activity and docking study of 2-amino-4H-benzochromene-3-carbonitrile derivatives

    NASA Astrophysics Data System (ADS)

    Mirjalili, BiBi Fatemeh; Zamani, Leila; Zomorodian, Kamiar; Khabnadideh, Soghra; Haghighijoo, Zahra; Malakotikhah, Zahra; Ayatollahi Mousavi, Seyyed Amin; Khojasteh, Shaghayegh

    2016-07-01

    Pathogenic fungi are associated with diseases ranging from simple dermatosis to life-threatening infections, particularly in immunocompromised patients. During the past two decades, resistance to established antifungal drugs has increased dramatically and has made it crucial to identify novel antimicrobial compounds. Here, we selected 12 new compounds of 2-amino-4H-benzochromene-3-carbonitrile drivetives (C1-C12) for synthesis by using nano-TiCl4.SiO2 as efficient and green catalyst, then nine of synthetic compounds were evaluated against different species of fungi, positive gram and negative gram of bacteria. Standard and clinical strains of antibiotics sensitive and resistant fungi and bacteria were cultured in appropriate media. Biological activity of the 2-amino-4H-benzochromene-3-carbonitrile derivatives against fungi and bacteries were estimated by the broth micro-dilution method as recommended by clinical and laboratory standard institute (CLSI). In addition minimal fangicidal and bactericial concenteration of the compounds were also determined. Considering our results showed that compound 2-amino-4-(4-methyl benzoate)-4H-benzo[f]chromen-3-carbonitrile (C9) had the most antifungal activity against Aspergillus clavatus, Candida glabarata, Candida dubliniensis, Candida albicans and Candida tropicalis at concentrations ranging from 8 to ≤128 μg/mL. Also compounds 2-amino-4-(3,4-dimethoxyphenyl)-4H-benzo[f]chromen-3-carbonitrile (C4) and 2-amino-4-(4-isopropylphenyl)-4H-benzo[f]chromen-3-carbonitrile (C3) had significant inhibitory activities against Epidermophyton floccosum following 2-amino-4-(4-methylbenzoate)-4H-benzo[f]chromen-3-carbonitrile (C9), respectively. Docking simulation was performed to insert compounds C3, C4 and C9 in to CYP51 active site to determine the probable binding model.

  7. Synthesis of [1,2-3H2]cholecalciferol and metabolism of [4-14C,1,2-3H2]- and [4-14C,1-3H]-cholecalciferol in rachitic rats and chicks

    PubMed Central

    Lawson, D. E. M.; Pelc, B.; Bell, P. A.; Wilson, P. W.; Kodicek, E.

    1971-01-01

    [1,2-3H2]Cholecalciferol has been synthesized with a specific radioactivity of 508mCi/mmol by using tristriphenylphosphinerhodium chloride, the homogeneous hydrogen catalyst. With doses of 125ng (5i.u.) of [4-14C,1-3H2]cholecalciferol the tissue distribution in rachitic rats of cholecalciferol and its metabolites (25-hydroxycholecalciferol and peak P material) was similar to that found in chicken with 500ng doses of the double-labelled vitamin. The only exceptions were rat kidney, with a very high concentration of vitamin D, and rat blood, with a higher proportion of peak P material, containing a substance formed from vitamin D with the loss of hydrogen from C-1. Substance P formed from [4-14C,1,2-3H2]cholecalciferol retained 36% of 3H, the amount expected from its distribution between C-1 and C-2, the 3H at C-1 being lost. 25-Hydroxycholecalciferol does not seem to have any specific intracellular localization within the intestine of rachitic chicks. The 3H-deficient substance P was present in the intestine and bone 1h after a dose of vitamin D and 30min after 25-hydroxycholecalciferol. There was very little 25-hydroxycholecalciferol in intestine at any time-interval, but bone and blood continued to take it up over the 8h experimental period. It is suggested that the intestinal 3H-deficient substance P originates from outside this tissue. The polar metabolite found in blood and which has retained its 3H at C-1 is not a precursor of the intestinal 3H-deficient substance P. PMID:4329870

  8. Transition metal swift heavy ion implantation on 4H-SiC

    NASA Astrophysics Data System (ADS)

    Ali, A. Ashraf; Kumar, J.; Ramakrishnan, V.; Asokan, K.

    2016-03-01

    This work reports on the realization of Quantum Ring (QR) and Quantum Dot (QD) like structures on 4H-SiC through SHI implantation and on their Raman studies. 4H-SiC is SHI implanted with Transition Metal (TM) Ni ion at different fluences. It is observed that a vibrational mode emerges as the result of Ni ion implantation. The E2 (TO) and the A1 (LO) are suppressed as the fluence increases. In this paper Raman and AFM studies have been performed at room temperature and the queer anomalies are addressed so new devices can be fabricated.

  9. Crystal and molecular structure of 2,4,4-trisubstituted 5-amino-4 H-imidazoles

    NASA Astrophysics Data System (ADS)

    Bellanato, J.; Avendaño, C.; Ramos, M. T.; Smith-Verdier, P.; Florencio, F.; Garcia-Blanco, S.

    Three 5-amino-4 H-imidazole derivatives 2(2-pyridyl) and 2-ethoxycarbonyl-4,4-pentamethylene-5-amino-and 2(2-pyridyl)-4,4-dimethyl-5(2-pyridylamino)4 H-imidazoles have been studied by i.r. and Raman spectroscopy. The crystal structure of one has been determined by X-ray diffraction. The tautomeric amino-imino equilibrium in different working conditions is also studied from spectroscopic data. The amino and the unconjugated imino forms are characterized.

  10. Analysis of Surface Defects on the Reverse Characteristics of 4H-SiC JBS Diode

    NASA Astrophysics Data System (ADS)

    Katsuno, Takashi; Watanabe, Yukihiko; Fujiwara, Hirokazu; Konishi, Masaki; Yamamoto, Takeo; Endo, Takeshi; Ishiko, Masayasu

    The good relations between the reverse characteristics of 4H-SiC JBS diodes and the surface defects were obtained. The reverse characteristics of 4H-SiC JBS diodes were categorized in three groups as follows: (A) low blocking voltage, (B) high leakage current and (C) low leakage current. The groups of (A) and (B) were caused by the existences of the micropipe and small particles, and the carrot-like defects on the SiC surfaces, respectively. In group (C), there was no defect on the surfaces observed by the optical microscope. The structure of carrot-like defect was analyzed by the cathode-luminescence and TEM.

  11. Managing for Motivation: Herzberg's Motivation-Hygiene Theory and Its Application to 4-H Leadership. National Intern Report.

    ERIC Educational Resources Information Center

    Freeman, Walter J.

    A study examined the organizational factors contributing to the motivation of 4-H volunteer leaders. A modified form of Herzberg's Motivation-Hygiene Theory served as the research design of the study. A total of 149 4-H leaders were interviewed regarding thirteen job factors: recognition; personal growth; relationships with other 4-H leaders,…

  12. Current Practices for Training Staff to Accommodate Youth with Special Health Care Needs in the 4-H Camp Setting

    ERIC Educational Resources Information Center

    Mouton, Lauren; Bruce, Jacklyn

    2013-01-01

    The theory of inclusion is the foundation for the study reported here; inclusion is a focus not only of formal education, but also of nonformal educational settings such as 4-H. Ideally, 4-H camps are designed to serve youth of all backgrounds and abilities. By accommodating youth with special health care needs, 4-H camps are effectively meeting…

  13. Maine 4-H Afterschool Academy--A Professional Development Opportunity for Out-of-School-Time Providers

    ERIC Educational Resources Information Center

    Lobley, Jennifer; Ouellette, Kristy L.

    2013-01-01

    The Maine 4-H Afterschool Academy trained 369 after-school and out of school time providers in 2011. This easy-to-adapt professional development opportunity used blended learning, a combination of in-person and Web-based opportunities. Providers successfully learned concepts and practical knowledge regarding 4-H, specifically 4-H Science. In…

  14. E-Learning for 4-H Volunteers: Who Uses It, and What Can We Learn from Them?

    ERIC Educational Resources Information Center

    Ouellette, Kristy L.; Lesmeister, Marilyn K.; Lobley, Jennifer; Gross, Kerry M.

    2014-01-01

    Orienting and training 4-H volunteers are critical to individuals and the organization. The two-part study reported here re-establishes the profile of the 4-H volunteer and evaluates both the format and content of e-Learning for 4-H Volunteers modules launched in 2006. Volunteers from seven states perceived that online modules made learning more…

  15. A theoretical study of the CH[sub 3]+C[sub 2]H[sub 2] reaction

    SciTech Connect

    Diau, E.W.; Lin, M.C. ); Melius, C.F. )

    1994-09-01

    The rate constants for the formation of various products in the CH[sub 3]+C[sub 2]H[sub 2] reaction have been computed by multichannel RRKM calculations using the molecular and transition-state parameters predicted by the BAC-MP4 method. The results of the calculations agree quantitatively with experimental data obtained under varying conditions: [ital T]=300--2200 K, [ital P]=30--2500 Torr. At low temperatures ([ital T][lt]1300 K), the CH[sub 3]+C[sub 2]H[sub 2] reaction is dominated by the addition-stabilization process producing CH[sub 3]C[sub 2]H[sub 2]. Under high-temperature ([ital T][gt]1400 K) and atmospheric-pressure conditions, the reaction occurs primarily by the CH[sub 3]-for-H displacement process producing CH[sub 3]C[sub 2]H, a likely source of the C[sub 3]H[sub 3] radical (which has recently been shown to be a key precursor of C[sub 6]H[sub 6] in hydrocarbon combustion reactions).

  16. Unimolecular reaction mechanisms involving C{sub 3}H{sub 4}, C{sub 4}H{sub 4}, and C{sub 6}H{sub 6} hydrocarbon species

    SciTech Connect

    Melius, C.F.; Miller, J.A.; Evleth, E.M.

    1991-12-31

    The unimolecular rearrangement processes of unsaturated aliphatic hydrocarbons representative of intermediates in rich hydrocarbon flames have been investigated using the quantum chemical BAC-MP4 method. In particular, we have investigated the unimolecular reaction mechanisms involving (1) allene-cyclopropene-propyne rearrangement, (2) vinylacetylene pyrolysis leading to acetylene and diacetylene, and (3) various C{sub 6}H{sub 6} compounds, including 1,5-hexadiyne, 1,2,4,5-hexatetraene, and 1,2-hexadin-5-yne leading to 3,4-dimethylenecyclobutene, fulvene, benzene, 2-ethynyl-1,3-butadiene, and other C{sub 6}H{sub 6} species. Rate constants for various reaction steps give food agreement with available experimental measurements. The reaction mechanisms are also consistent with various deuterium isotope labeling experiments. The results indicate that many different types of reaction mechanisms occur, including concerted pathways involving carbene and vinylidene intermediates and insertion reactions of vinylidenes into C-H bonds and C-C multiple bonds. New decomposition pathways are presented for vinylacetylene pyrolysis, for conversion of 1,2-hexadien-5-yne to fulvene, and for conversion of fulvene to benzene.

  17. Seven 3-methylidene-1H-indol-2(3H)-ones related to the multiple-receptor tyrosine kinase inhibitor sunitinib.

    PubMed

    Spencer, John; Chowdhry, Babur Z; Hamid, Samiyah; Mendham, Andrew P; Male, Louise; Coles, Simon J; Hursthouse, Michael B

    2010-02-01

    The solid-state structures of a series of seven substituted 3-methylidene-1H-indol-2(3H)-one derivatives have been determined by single-crystal X-ray diffraction and are compared in detail. Six of the structures {(3Z)-3-(1H-pyrrol-2-ylmethylidene)-1H-indol-2(3H)-one, C(13)H(10)N(2)O, (2a); (3Z)-3-(2-thienylmethylidene)-1H-indol-2(3H)-one, C(13)H(9)NOS, (2b); (3E)-3-(2-furylmethylidene)-1H-indol-2(3H)-one monohydrate, C(13)H(9)NO(2).H(2)O, (3a); 3-(1-methylethylidene)-1H-indol-2(3H)-one, C(11)H(11)NO, (4a); 3-cyclohexylidene-1H-indol-2(3H)-one, C(14)H(15)NO, (4c); and spiro[1,3-dioxane-2,3'-indolin]-2'-one, C(11)H(11)NO(3), (5)} display, as expected, intermolecular hydrogen bonding (N-H...O=C) between the 1H-indol-2(3H)-one units. However, methyl 3-(1-methylethylidene)-2-oxo-2,3-dihydro-1H-indole-1-carboxylate, C(13)H(13)NO(3), (4b), a carbamate analogue of (4a) lacking an N-H bond, displays no intermolecular hydrogen bonding. The structure of (4a) contains three molecules in the asymmetric unit, while (4b) and (4c) both contain two independent molecules. PMID:20124685

  18. [[sup 3]H] Thymidine incorporation to estimate growth rates of anaerobic bacterial strains

    SciTech Connect

    Winding, A. )

    1992-08-01

    The incorporation of [[sup 3]H] thymidine by axenic cultures of anaerobic bacteria was investigated as a means to measure growth. The three fermentative strains and one of the methanogenic strains tested incorporated [[sup 3]H] thymidine during growth. It is concluded that the [[sup 3]H] thymidine incorporation method underestimates bacterial growth in anaerobic environments.

  19. Meridional Variations of C2H2 and C2H6 in Jupiter's Atmosphere from Cassini CIRS Infrared Spectra

    NASA Technical Reports Server (NTRS)

    Nixon, C. A.; Achterberg, R. K.; Conrath, B. J.; Irwin, P. G. J.; Fouchet, T.; Parrish, P. D.; Abbas, M.; LeClaire, A.; Romani, P. N.; Simon-Miller, A. A.

    2004-01-01

    The abundances of hydrocarbons such as acetylene (C2H2) and ethane (C2H6) in Jupiter's atmosphere are important physical quantities, constraining our models of the chemical and dynamical processes. However, our knowledge of these quantities and their vertical and latitudinal variations has remained sparse. The flyby of the Cassini spacecraft with Jupiter at the end of 2000 provided an excellent opportunity to observe the infrared spectrum with the Composite Infrared Spectrometer (CIRS) instrument, mapping the spatial variation of emissions from 10-1400 cm-1. CIRS spectra taken at the highest resolution (0.5 cm-1) in early December 2000 have been analysed to infer atmospheric temperatures in the stratosphere at 0.5-20 mbar via the v4 of CH4, and in the troposphere at 100-400 mbar, via the hydrogen collision-induced continuum absorption at 600-800 cm. Simultaneously, we have searched for meridional abundance variations in C2H2 and C2H6 via the v5 and vg bands respectively. Tropospheric absorption and stratospheric emission are highly anti-correlated at the CIM resolution, introducing a non-uniqueness into the retrievals, which means that vertical gradient and column abundance cannot be simultaneously found without additional constraints. If we assume the profile shapes from photochemical model calculations, we show that the column abundance of C2H2 must decrease sharply towards the poles, while C2H6 is constant or slightly increasing. The relevance of these results to current photochemical and dynamical knowledge of Jupiter's atmosphere is discussed.

  20. Evaluation of an electrochemical N2/H2 gas separator

    NASA Technical Reports Server (NTRS)

    Marshall, R. D.; Wynveen, R. A.; Carlson, J. N.

    1973-01-01

    A program was successfully completed to evaluate an electrochemical nitrogen/hydrogen (N2/H2) separator for use in a spacecraft nitrogen (N2) generator. Based on the technical data obtained a N2/H2 separator subsystem consisting of an organic polymer gas permeator first stage and an electrochemical second and third stage was estimated to have the lowest total spared equivalent weight, 257 kg (566 lb), for a 15 lb/day N2 generation rate. A pre-design analysis of the electrochemical N2/H2 separator revealed that its use as a first stage resulted in too high a power requirement to be competitive with the organic polymer membrane and the palladium-silver membrane separation methods. As a result, program emphasis was placed on evaluating the electrochemical. A parametric test program characterized cell performance and established second- and third-stage electrochemical N2/H2 separator operating conditions. A design verification test was completed on the second and third stages. The second stage was then successfully endurance tested for 200 hours.

  1. The distribution and abundance of interstellar C2H

    NASA Technical Reports Server (NTRS)

    Huggins, P. J.; Carlson, W. J.; Kinney, A. L.

    1984-01-01

    C2H(N = 1-0) emission has been extensively observed in a variety of molecular clouds, including: 12 hot, dense, cloud cores, 3 bright-rimmed clouds (in NGC 1977, IC 1396, and IC 1848), and across the extended OMC - 1 cloud. It has also been observed in the circumstellar envelopes IRC + 10216 and AFGL 2688. Abundance analyses of the molecular clouds yield C2H/(C-13)O abundance ratios of about 0.01, with little variation (less than about a factor of 4) either between clouds or across individual clouds. In the Orion plateau source, the C2H abundance is enhanced by less than a factor of 4, relative to the extended cloud. The generally high levels of C2H found in the molecular clouds are not readily accounted for by simple, steady-state chemical models, and suggest, as do earlier observations of atomic carbon, that the carbon chemistry in dense clouds is more active than is commonly assumed.

  2. SPECTROSCOPIC CONSTANTS FOR {sup 13}C AND DEUTERIUM ISOTOPOLOGUES OF CYCLIC AND LINEAR C{sub 3}H{sub 3}{sup +}

    SciTech Connect

    Huang Xinchuan; Lee, Timothy J. E-mail: Timothy.J.Lee@nasa.gov

    2011-07-20

    Recently, we reported ab initio quartic force fields (QFFs) for the cyclic and linear forms of the C{sub 3}H{sub 3}{sup +} molecular cation, referred to as c-C{sub 3}H{sub 3}{sup +} and l-C{sub 3}H{sub 3}{sup +}. These were computed using high levels of theory. Specifically the singles and doubles coupled-cluster method that includes a perturbational estimate of connected triple excitations, CCSD(T), was used in conjunction with extrapolation to the one-particle basis set limit, and corrections for scalar relativity and core correlation were included. In the present study, we use these QFFs to compute highly accurate fundamental vibrational frequencies and other spectroscopic constants for the c-{sup 13}CC{sub 2}H{sub 3}{sup +}, c-C{sub 3}H{sub 2}D{sup +}, c-{sup 13}CC{sub 2}H{sub 2}D{sup +} isotoplogues of c-C{sub 3}H{sub 3}{sup +}, and the H{sub 2}CCCD{sup +}, HDCCCH{sup +}, H{sub 2}{sup 13}CCCH{sup +}, H{sub 2}C{sup 13}CCH{sup +}, and H{sub 2}CC{sup 13}CH{sup +} isotopologues of l-C{sub 3}H{sub 3}{sup +}. Improvements in ab intitio methods have now made it possible to identify small molecules in an astronomical observation without the aid of high-resolution experimental data. We also report dipole moment values and show that the above-mentioned cyclic isotopologues have values of 0.094, 0.225, and 0.312 D, respectively, while the l-C{sub 3}H{sub 3}{sup +} isotopologues have values that range between 0.325 and 0.811 D. Thus, it is hoped that the highly accurate spectroscopic constants and data provided herein for the {sup 13}C and deuterium isotopologues of the cyclic and linear forms of C{sub 3}H{sub 3}{sup +} will enable their identification in astronomical observations from the Herschel Space Observatory, the Stratospheric Observatory for Infrared Astronomy, the Atacama Large Millimeter Array, and in the future, the James Webb Space Telescope.

  3. Conformation-Specific Infrared Spectroscopy of γ2-PEPTIDE Foldamers: Ac-γ2-hPhe-γ2-hAla-NHMe and Ac-γ2-hAla-γ2-hPhe-NHMe

    NASA Astrophysics Data System (ADS)

    James, William H., III; Buchanan, Evan G.; Müller, Christian W.; Zwier, Timothy S.; Guo, Li; Gellman, Samuel H.

    2010-06-01

    IR/UV double-resonance spectroscopy has been used to study the intrinsic conformational preferences of naturally occurring and synthetic peptides. These studies demonstrated the power of double-resonance methods and highlighted the ability of even short peptide mimics to form a variety of intramolecular hydrogen bonded architectures. Currently, we are extending these studies to a series of model γ2-peptides, which differ from α-peptides by virtue of having two additional, substitutable methylene units separating amide groups in the peptide backbone. Initial studies centered on the conformation-specific infrared spectra of Ac-γ2-hPhe-NHMe, where three unique conformational isomers (two hydrogen-bonded and one intramolecular amide stacked) were observed under the isolated-molecule conditions of a jet-cooled environment. This talk will focus on on two larger γ2-peptides, Ac-γ2-hPhe-γ2-hAla-NHMe and Ac-γ2-hAla-γ2-hPhe-NHMe. Utilizing resonant ion-dip infrared spectroscopy, the single-conformation infrared spectra of eight resolved conformers of the two molecules were recorded in the amide NH stretch region. The resulting infrared spectra of the tri-amides contain evidence for structures comprised of one, two, and three intramolecular amide-amide hydrogen bonds, the last of which is unprecedented for a tri-amide. In an effort to make firm conformational assignments, the spectroscopic data will be compared to the results of harmonic vibrational frequency calculations using traditional DFT and dispersion-corrected DFT methods, the results of which will be discussed.

  4. Children and their 4-H animal projects: How children use science in agricultural activity

    NASA Astrophysics Data System (ADS)

    Emo, Kenneth Roy

    Many children are introduced to science through informal educational programs. 4-H, an educational youth program, has a history of introducing scientific practices into agriculture. The purpose of this ethnographically-driven case study is to examine how science informs the actions of children raising market animals in a 4-H project. For two years the researcher collected data on 4-H children with market animal projects. Observations, interviews, and artifacts gathered are interpreted using the framework of activity theory. This study provides evidence for how the context of an activity system influences individual actions. Rules developed by the organization guide the actions of children to incorporate physical and psychological tools of science into their project to achieve the object: producing animals of proper weight and quality to be competitive in the county fair. Children learn the necessary actions from a community of practitioners through which expertise is distributed. Children's learning is demonstrated by the way their participation in their project changes with time, from receiving assistance from others to developing expertise in which they provide assistance to others. The strength of this educational experience is how children apply specific tools of science in ways that provide meaning and relevancy to their 4-H activity.

  5. More than Cows & Cooking: Newest Research Shows the Impact of 4-H.

    ERIC Educational Resources Information Center

    Astroth, Kirk A.; Haynes, George W.

    2002-01-01

    A Montana survey of 2,500 students' use of out-of-school time found that only 17% reported no involvement in out-of-school activities. 4-H participants were less likely to shoplift, steal, smoke cigarettes, ride with a drunk driver, or damage property. They were more likely to develop self-confidence and social competence, demonstrate leadership,…

  6. County Clustering for the California 4-H Youth Development Program: Impacts and Lessons Learned

    ERIC Educational Resources Information Center

    Subramaniam, Aarti; Dasher, Harry Steve; Young, Jane Chin

    2012-01-01

    In response to budgetary constraints, a new staffing structure, the Pilot Leadership Plan, was proposed for California's 4-H Youth Development Program. County clusters were formed, each led by a coordinator. The plan was piloted for 2 years to provide insight into how county clustering could support Extension staff to increase and enhance…

  7. 4-H Horticulture Project Activity Guides. Leader's Guide and Units 1-3.

    ERIC Educational Resources Information Center

    Illinois Univ., Urbana. Cooperative Extension Service.

    This document, concerning the 4-H horticulture project, includes a leader's guide and three youth activity guides. The leader's guide can be used to plan group project meetings that are both fun and educational. Activities can be adapted to various age groups. The leader's guide includes basic information for growing plants indoors and outdoors,…

  8. Promoting the Essential Elements of 4-H Youth Development through an Experiential Learning Model

    ERIC Educational Resources Information Center

    Meyer, Shelley; Jones, Kenneth R.

    2015-01-01

    The purpose of the project reported here was to apply Experiential Learning Theory to a context involving middle and high school aged youth while assessing the four concepts (belonging, mastery, independence, and generosity) in relation to the 4-H youth development essential elements. The conclusions of the project's evaluation suggest…

  9. 4-H Chickquest: Connecting Agri-Science with STEM Standards in Urban Schools

    ERIC Educational Resources Information Center

    Horton, Robert L.; Krieger, Jackie; Halasa, Katrina

    2013-01-01

    While young students are more capable of scientific inquiry than previously believed, elementary school teachers are often inexperienced in and lack confidence with teaching science. ChickQuest is a 4-H-created embryology curriculum for third-graders that meets Ohio state science standards, teaches STEM skills, and promotes ongoing interaction…

  10. Possession, Transportation, and Use of Firearms by Older Youth in 4-H Shooting Sports Programs

    ERIC Educational Resources Information Center

    White, David J.; Williver, S. Todd

    2014-01-01

    Thirty years ago we would think nothing of driving to school with a jackknife in our pocket or rifle in the gun rack. Since then, the practices of possessing, transporting, and using firearms have been limited by laws, rules, and public perception. Despite restrictions on youth, the Youth Handgun Safety Act does afford 4-H shooting sports members…

  11. 4-H Tractor Operator Program Teaches Employability Skills and Safety to Youth

    ERIC Educational Resources Information Center

    Barrett, Debra K.

    2013-01-01

    For Michigan State University Extension, the Berrien County 4-H Tractor Operator Program has provided tractor safety education to teens for over 30 years. The certification training satisfies current requirements for operation of a 20 PTO HP or greater agricultural tractor by 14- and 15-year-old youth employed on property "not" owned,…

  12. Stakeholder Satisfaction with a 4-H Extension Program for Five- to Eight-Year-Old Children.

    ERIC Educational Resources Information Center

    Scheer, Scott D.; Lafontaine, Kenneth R.

    1999-01-01

    A 4-H K-2 program was evaluated by 277 parents, 144 volunteers, and 44 extension agents. These stakeholders believed the program was beneficial and effective in improving children's life skills (self-esteem, making friends, making choices, learning and physical skills). (SK)

  13. Performance statistics of the FORTRAN 4 /H/ library for the IBM system/360

    NASA Technical Reports Server (NTRS)

    Clark, N. A.; Cody, W. J., Jr.; Hillstrom, K. E.; Thieleker, E. A.

    1969-01-01

    Test procedures and results for accuracy and timing tests of the basic IBM 360/50 FORTRAN 4 /H/ subroutine library are reported. The testing was undertaken to verify performance capability and as a prelude to providing some replacement routines of improved performance.

  14. Life Skill Development Related to Participation in 4-H Animal Science Projects.

    ERIC Educational Resources Information Center

    Ward, Carol Knowlton

    1996-01-01

    Alumni of 4-H animal science programs in New Jersey were surveyed (n=52). Participation had a positive influence on life skill development, especially "accepting responsibility." Experience with shows and judging was beneficial to public speaking/job interview skills. Although many were not in animal science careers, they enjoyed related hobbies.…

  15. A Beach and Dune Community. 4-H Marine Science. Member's Guide. Activity I. MSp 1.

    ERIC Educational Resources Information Center

    Auburn Univ., AL. Cooperative Extension Service.

    The investigation in this booklet is designed to provide 4-H members with opportunities to identify common plants and animals found on beaches and sand dunes and to determine the role of the plants and animals in this community. Learners are provided with a picture of a hypothetical beach and sand dune and a list of organisms (included in the…

  16. The Big E (Energy). 4-H Leader's Guide for Units 2 & 3.

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This leader's guide is designed for units 2 and 3 of the Nebraska 4-H Energy Project. The goals of the project are to: (1) help young people understand energy problems related to life styles; (2) use energy resources carefully; (3) guide members in choosing their own energy alternatives; and (4) to enjoy together the challenges and creativity of…

  17. CareerSmarts. 4-H Mentoring Program. Agent's Handbook. Mentor's Handbook. Protege's Handbook.

    ERIC Educational Resources Information Center

    Locklear, Eddie L.

    The North Carolina 4-H CareerSmarts Program is designed to unite the public and private sectors to provide career education for young people. This packet contains three handbooks (for agents, proteges, and mentors) that explain the program and outline practical ways to conduct it. CareerSmarts consists of three phases. Phase one is conducted…

  18. Louisiana 4-H Seeds of Service School Gardens: A Descriptive View

    ERIC Educational Resources Information Center

    Cater, Melissa; Fox, Janet; Fletcher, Bobby Jr.

    2012-01-01

    Louisiana 4-H Seeds of Service School Gardens, a K-12 Learn and Serve Grant program, provides a descriptive view of how school gardens along with classroom instruction link curriculum to outdoor classrooms. The purpose of the process evaluation was to describe curriculum implementation fidelity, reach of the gardening program to participants, use…

  19. Bufexamac ameliorates LPS-induced acute lung injury in mice by targeting LTA4H.

    PubMed

    Xiao, Qiang; Dong, Ningning; Yao, Xue; Wu, Dang; Lu, Yanli; Mao, Fei; Zhu, Jin; Li, Jian; Huang, Jin; Chen, Aifang; Huang, Lu; Wang, Xuehai; Yang, Guangxiao; He, Guangyuan; Xu, Yong; Lu, Weiqiang

    2016-01-01

    Neutrophils play an important role in the occurrence and development of acute lung injury (ALI). Leukotriene B4 (LTB4), a hydrolysis product of epoxide leukotriene A4 (LTA4) catalyzed by LTA4 hydrolase (LTA4H), is one of the most potent chemoattractants for neutrophil. Bufexamac is a drug widely used as an anti-inflammatory agent on the skin, however, the mechanism of action is still not fully understood. In this study, we found bufexamac was capable of specifically inhibiting LTA4H enzymatic activity and revealed the mode of interaction of bufexamac and LTA4H using X-ray crystallography. Moreover, bufexamac significantly prevented the production of LTB4 in neutrophil and inhibited the fMLP-induced neutrophil migration through inhibition of LTA4H. Finally, bufexamac significantly attenuated lung inflammation as reflected by reduced LTB4 levels and weakened neutrophil infiltration in bronchoalveolar lavage fluid from a lipopolysaccharide-induced ALI mouse model. In summary, our study indicates that bufexamac acts as an inhibitor of LTB4 biosynthesis and may have potential clinical applications for the treatment of ALI. PMID:27126280

  20. Temperature Dependence of Attenuation of Coplanar Waveguide on 4H High Resistivity SIC Through 540C

    NASA Technical Reports Server (NTRS)

    Ponchak, G. E.; Schwartz, Z.; Alterovitz, S. A.; Downey, A. N.; Freeman, J. C.

    2003-01-01

    For the first time, the temperature and frequency dependence of the attenuation of a Coplanar Waveguide (CPW) on 4H, High Resistivity Sic substrate is reported. The low frequency attenuation increases by 2 dB/cm at 500 C and the high frequency attenuation increases by 3.3 dB/cm at 500 C compared to room temperature.

  1. The Value of 4-H Judging Teams--Missouri Dairy Judging Alumni Survey

    ERIC Educational Resources Information Center

    Deaver, Karla; Probert, Ted

    2016-01-01

    Former Missouri 4-H Dairy Judging Team members responded to a survey about life skills development and the value of the judging team experience. Results of the survey indicate that judging team experience was highly influential in the development of communication, public speaking, and presentation skills. Respondents also indicated that judging…

  2. Formation of low-temperature cirrus from H2SO4/H2O aerosol droplets.

    PubMed

    Bogdan, A; Molina, M J; Sassen, K; Kulmala, M

    2006-11-23

    We present experimental results obtained with a differential scanning calorimeter (DSC) that indicate the small ice particles in low-temperature cirrus clouds are not completely solid but rather coated with an unfrozen H2SO4/H2O overlayer. Our results provide a new look on the formation, development, and microphysical properties of low-temperature cirrus clouds. PMID:17107102

  3. Bufexamac ameliorates LPS-induced acute lung injury in mice by targeting LTA4H

    PubMed Central

    Xiao, Qiang; Dong, Ningning; Yao, Xue; Wu, Dang; Lu, Yanli; Mao, Fei; Zhu, Jin; Li, Jian; Huang, Jin; Chen, Aifang; Huang, Lu; Wang, Xuehai; Yang, Guangxiao; He, Guangyuan; Xu, Yong; Lu, Weiqiang

    2016-01-01

    Neutrophils play an important role in the occurrence and development of acute lung injury (ALI). Leukotriene B4 (LTB4), a hydrolysis product of epoxide leukotriene A4 (LTA4) catalyzed by LTA4 hydrolase (LTA4H), is one of the most potent chemoattractants for neutrophil. Bufexamac is a drug widely used as an anti-inflammatory agent on the skin, however, the mechanism of action is still not fully understood. In this study, we found bufexamac was capable of specifically inhibiting LTA4H enzymatic activity and revealed the mode of interaction of bufexamac and LTA4H using X-ray crystallography. Moreover, bufexamac significantly prevented the production of LTB4 in neutrophil and inhibited the fMLP-induced neutrophil migration through inhibition of LTA4H. Finally, bufexamac significantly attenuated lung inflammation as reflected by reduced LTB4 levels and weakened neutrophil infiltration in bronchoalveolar lavage fluid from a lipopolysaccharide-induced ALI mouse model. In summary, our study indicates that bufexamac acts as an inhibitor of LTB4 biosynthesis and may have potential clinical applications for the treatment of ALI. PMID:27126280

  4. Participant Comfort with and Application of Inquiry-Based Learning: Results from 4-H Volunteer Training

    ERIC Educational Resources Information Center

    Haugen, Heidi; Stevenson, Anne; Meyer, Rebecca L.

    2016-01-01

    This article explores how a one-time training designed to support learning transfer affected 4-H volunteers' comfort levels with the training content and how comfort levels, in turn, affected the volunteers' application of tools and techniques learned during the training. Results of a follow-up survey suggest that the training participants…

  5. Bio-Security Proficiencies Project for Beginning Producers in 4-H

    ERIC Educational Resources Information Center

    Smith, Martin H.; Meehan, Cheryl L.; Borba, John A.

    2014-01-01

    Improving bio-security practices among 4-H members who raise and show project animals is important. Bio-security measures can reduce the risk of disease spread and mitigate potential health and economic risks of disease outbreaks involving animal and zoonotic pathogens. Survey data provided statistical evidence that the Bio-Security Proficiencies…

  6. 4H-SiC photodiode model for DC SPICE circuit simulation

    NASA Astrophysics Data System (ADS)

    Kociubiński, Andrzej; Duk, Mariusz; Korona, Mateusz; Muzyka, Krzysztof

    2015-09-01

    Technology, characterization and in particularly modeling of 4H-SiC photodiode have been presented in this paper. Modeling and simulation has been performed using PSPICE environment. Comparison of simulation with real results for electrical characteristic (I-V) of circular SiC photodiodes has been also presented.

  7. Associated Factors in Recruitment and Retention of 4-H Members in West Virginia.

    ERIC Educational Resources Information Center

    Wingenbach, Gary J.; Meighan, Terence; Lawrence, Layle D.; Gartin, Stacy A.; Woloshuk, Jean M.

    1999-01-01

    Extension agents and 4-H Club leaders (n=115) rated the following as effective recruitment techniques: an active club, word of mouth, interesting programs, and members' active role. Successful retention techniques included effective leaders; praise, motivation, and encouragement; and fun meetings, programs, and activities. (SK)

  8. An Evaluation of the 4-H "Health Rocks" Program: Implications for Program Improvement

    ERIC Educational Resources Information Center

    Self, Carlton; Morgan, A. Christian; Fuhrman, Nicholas E.; Navarro, Maria

    2013-01-01

    The National 4-H Council developed the Health Rocks substance abuse educational program to prevent youth from engaging in risky behaviors. The program was presented in 2010 to more than 8,000 middle school youth in Georgia. A post-then-pre evaluation was conducted with youth who completed 10 hours of instruction to determine if changes in youth…

  9. South Carolina's Model for Initiating Hispanic 4-H Clubs

    ERIC Educational Resources Information Center

    Lippert, Robert; Rembert, Kellye

    2012-01-01

    Over the past 5 years, through the initiative of several county Extension agents, South Carolina 4-H has established a successful model for bringing Hispanic youth into our program. We have found the most effective method is to initiate contact and establish partnerships with the principals and ESOL instructors in the local schools. Through this…

  10. The Big E (Energy). 4-H Leader's Guide [for Unit 1].

    ERIC Educational Resources Information Center

    Caldwell, William; And Others

    This guide is designed for leaders of the Nebraska 4-H Energy Project. The goals of the project are to: (1) help young people understand energy problems related to life styles; (2) use energy resources carefully; (3) guide members in choosing their own energy alternatives; and (4) enjoy together the challenges and creativity of finding energy…

  11. A Partnership Model for Training Episodic Environmental Stewardship 4-H Volunteers

    ERIC Educational Resources Information Center

    Young, Jane Chin; Alexander, Janice; Smith, Martin H.

    2013-01-01

    The Marin Environmental Stewardship pilot project demonstrates the potential for a partnership model that brings together external and internal collaborators to recruit and train episodic 4-H volunteers to meet environmental education needs within a community. The clientele served by the volunteers trained through the project was at-risk, urban…

  12. Photoaffinity labeling of opiate receptors using intrinsically photoactive /sup 3/H-opiates

    SciTech Connect

    Kooper, G.N.; Levinson, N.R.; Copeland, C.F.; Bowen, W.D.

    1988-03-01

    Opiate receptors in rat and cow brain membranes have been labeled irreversibly using the intrinsic photolability of 3H-opiates. Membranes were incubated with 3H-ligand and then irradiated with UV light of 254 nm. Nonspecific binding was determined in the presence of 10 microM unlabeled levallorphan. Irreversible binding was defined as binding which survived heat or acid denaturation of membranes. Specific incorporation of label into denatured samples was observed only when unbound or loosely bound 3H-ligand was washed free from the membranes prior to irradiation. There was a general correlation between photosensitivity of the 3H-ligand and its ability to photolabel receptors. Hence, photolabeling presumably results by covalent attachment of highly reactive species generated during photochemical decomposition of ligand. With 3H-etorphine, optimal irradiation time was 5 min. In addition to 3H-etorphine, receptors could be labeled irreversibly with 3H-oxymorphone, 3H-dihydromorphine, and 3H-ethylketocyclazocine. Of the specific binding present in irradiated, nondenatured samples, 45-60% remained attached to receptors upon denaturation. 3H-Ethylketocyclazocine exhibited an 86% yield of incorporation. Signal-to-noise levels of 50-80% could be achieved in denatured samples. Therefore, this method provides a means of covalently labeling opiate receptors in high yield and with high signal-to-noise ratios. The opioid peptides, 3H-D-Ala2,D-Leu5-enkephalin, 3H-D-Ser2,Leu5,Thr6-enkephalin, 3H-D-Ala2,Met5-enkephalin amide, and 3H-D-Ala2,N-MePhe4,Gly-ol5-enkephalin, as well as the benzomorphan, 3H-bremazocine, apparently lack the structural characteristics which allow photolabeling.

  13. Using multiple youth programming delivery modes to drive the development of social capital in 4-H participants.

    PubMed

    Kinsey, Sharon

    2013-06-01

    This article focuses on how 4-H youth participants are building social capital, or connections among individuals and community members, through their 4-H experiences. These experiences can be seen through the lens of such 4-H delivery modes as the traditional 4-H club, after-school programs, and school enrichment programs. In addition, other experiences such as leadership camps and conferences or activities in the local community afford youth the opportunity to build the relationships, trust, and respect reflective of social capital. Examples are derived from 4-H program participants-urban, suburban and rural youth-in Camden County, New Jersey. PMID:23878086

  14. Reaction channels and spectroscopic constants of astrophysical relevant Silicon bearing molecules SiC3H,+ and SiC3H

    NASA Astrophysics Data System (ADS)

    Inostroza Pino, N.; Cardenas, C.; Fuentealba, P.

    2014-10-01

    Reaction channels and spectroscopic properties of a series of silicon-carbon-bearing isomers of SiC3H+ and SiC3H, which are suitable species for astrophysical detection in carbon-rich sources, are calculated with correlated ab initio CCSD(T) and density functional theory methods. We present four isomers of SiC3H+ for which the electronic ground states have closed-shell configurations. For SiC3H, we considered the same structures in order to present a complete study. The global minimum among the SiC3H+ isomers corresponds to the rhomboidal structure with a transannular bond in a 1A1 electronic state (rb3-SiC3H+ C2v X1A1). The next minima correspond to a second rhomboid 1A1 isomer and a linear isomer (X1Σ+) with relative energies 0.86 and 0.93 eV, respectively at the CCSD(T)/cc-pvTZ level of theory. The most stable mono-hydrogenated silicon carbon isomer is linear, followed by two rhomboidal isomers, rb2-SiC3H and rb3-SiC3H (0.23 and 0.31 eV). For each structure, a set of spectroscopic parameters including their equilibrium structures, rotational constants, harmonic frequencies and dipole moment is presented. Furthermore, we discuss plausible formation pathways of SiC3H+ isomers which are classified as charge-exchange, ion-neutral and dissociative recombination reactions. These results show one favourable pathway to produce rb3-SiC3H+ from rb-SiC3-3s. The formation energy of the cation's isomers coming from neutral isomers as linear l1-SiC3H, rb3-SiC3H and rb2-SiC3H plus H+ as reactants (charge-exchange reaction) are 203.8 kcal mol-1 (8.84eV), 175.4 kcal mol-1 (7.60 eV) and 195.2 kcal mol-1 (8.46 eV), which provides us with evidence of the endergonic character of these reactions. As a consequence, it does not seem to be feasible to produce a cation from neutral reactant plus H+ by a charge-exchange reaction that was proposed by UMIST.

  15. Chanabayaite, Cu2(N3C2H2)Cl(NH3,Cl,H2O,□)4, a new mineral containing triazolate anion

    NASA Astrophysics Data System (ADS)

    Chukanov, N. V.; Zubkova, N. V.; Möhn, G.; Pekov, I. V.; Pushcharovsky, D. Yu.; Zadov, A. E.

    2015-12-01

    A new mineral, chanabayaite, has been discovered at a guano deposit located at Mt. Pabellón de Pica near the village of Chanabaya, Iquique Province, Tarapacá region, Chile. It is associated with salammoniac, halite, joanneumite, nitratine and earlier chalcopyrite. Chanabayaite occurs as blue translucent imperfect prismatic crystals, up to 0.05 × 0.1 × 0.5 mm in size, and their radial aggregates. Chanabayaite is brittle, with a Mohs' hardness of 2. The cleavage is perfect on (001) and imperfect on (100) and (010). D meas = 1.48(2) g/cm3, D calc = 1.464 g/cm3. The mineral is optically biaxial (-), α = 1.561(2), β = 1.615(3), γ = 1.620(2), 2 V meas = 25(10)°, 2 V calc = 33°. Pleochroism is strong, Z ≈ Y (deep blue) ≫ X (pale blue with gray tint). IR spectrum is given. The chemical composition (electron microprobe data for Cu, Fe and Cl; gas chromatography data for H, N, C and O) is as follows (wt %): 32.23 Cu, 1.14 Fe, 16.13 Cl, 3.1 H, 29.9 N, 12.2 C, 3.4 O, total is 98.1. The empirical formula is ( Z = 4): Cu1.92Fe0.08Cl1.72N8.09C3.85H11.66O0.81. The structural model was based on the single-crystal X-ray diffraction data ( R = 0.1627). Chanabayaite is orthorhombic, space group Imma, a = 19.484(3), b = 7.2136(10), c = 11.999(4) Å, V = 1686.5(7) Å3, Z = 2. In chanabayaite, chains of the corner-sharing Cu(l)-centered octahedra and single Cu(2)-centered octahedra are linked via 1,2,4-triazolate anions C2N3H2 -. NH3 and Cl- are additional ligands coordinating Cu2+. Chanabayaite is a transformational mineral species formed by leaching of Na and one third of Cl and partial dehydration of the protophase Na2Cu2Cl3(N3C2H2)2(NH3)2 • 4H2O. The strongest reflections in the powder X-ray diffraction pattern [ d, Å ( I, %) ( hkl)] are detected: 10.19 (100) (101), 6.189 (40) (011), 5.729 (23) (301), 5.216 (75) (211, 202), 4.964 (20) (400), 2.830 (20) (602, 413, 503), 2.611 (24) (123, 422, 404).

  16. High efficiency 4H-SiC betavoltaic power sources using tritium radioisotopes

    NASA Astrophysics Data System (ADS)

    Thomas, Christopher; Portnoff, Samuel; Spencer, M. G.

    2016-01-01

    Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P+N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH3x) foil, or an integrated titanium tritide region formed by the diffusion of tritium into titanium. The specific activity of the source is directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm2. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm2, fill factor of 0.86, and power efficiency of 18.6%. Samples measured with an integrated source produced power efficiencies of 12%. Simulations were done to determine the beta spectrum (modified by self absorption) exiting the source and the electron hole pair generation function in the 4H-SiC. The electron-hole pair generation function in 4H-SiC was modeled as a Gaussian distribution, and a closed form solution of the continuity equation was used to analyze the cell performance. The effective surface recombination velocity in our samples was found to be 105-106 cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P+N junction structure can mitigate some of the negative effects.

  17. Search for the isomers of C2H3NO and C2H3NS in the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Etim, Emmanuel; Chakrabarti, Sandip Kumar; Das, Ankan; Gorai, Prasanta; Arunan, Elangannan

    2016-07-01

    With about 40% of all the known interstellar and circumstellar molecules having their isomeric analogues as known astromolecules, isomerism remains one of the leading themes in interstellar chemistry. In this regard, the recent detection of methyl isocyanate (with a number of isomeric analogues) in the Sgr B2(N) giant molecular cloud opens a new window for the possible astronomical detection of other C_2H_3NO isomers. The present work looks at the possibility of detecting other isomers of methyl isocyanate by considering different factors such as thermodynamic stability of the different isomers with respect to the Energy, Stability and Abundance (ESA) relationship, effect of interstellar hydrogen bonding with respect to the formation these isomers on the surface of the interstellar dust grains, possible formation routes for these isomers, spectroscopic parameters for potential astromolecules among these isomers, chemical modeling among other studies. The same studies are repeated for the C_2H_3NS isomers which are the isoelectroninc analogues of the C_2H_3NO isomers taking into account the unique chemistry of S and O-containing interstellar molecular species. Among the C_2H_3NS isomers, methyl isothiocyanate remains the most potential candidate for astronomical observation.

  18. The infrared spectra of C2H4(+) and C2H3 trapped in solid neon.

    PubMed

    Jacox, Marilyn E; Thompson, Warren E

    2011-02-14

    When a mixture of ethylene in a large excess of neon is codeposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, two groups of product absorptions appear in the infrared spectrum of the deposit. Similar studies using C(2)H(4)-1-(13)C and C(2)D(4) aid in product identification. The first group of absorptions arises from a cation product which possesses two identical carbon atoms, giving the first infrared identification of two fundamentals of C(2)H(4)(+) and three of C(2)D(4)(+), as well as a tentative identification of ν(9) of C(2)H(4)(+). The positions of these absorptions are consistent with the results of density functional calculations and of earlier photoelectron studies. All of the members of the second group of product absorptions possess two inequivalent carbon atoms. They are assigned to the vinyl radical, C(2)H(3), and to C(2)D(3), in agreement with other recent infrared assignments for those species. PMID:21322694

  19. Observations of CH4, C2H6, and C2H2 in the stratosphere of Jupiter.

    PubMed

    Sada, P V; Bjoraker, G L; Jennings, D E; McCabe, G H; Romani, P N

    1998-12-01

    We have performed high-resolution spectral observations at mid-infrared wavelengths of CH4 (8.14 micrometers), C2H6 (12.16 micrometers), and C2H2 (13.45 micrometers) on Jupiter. These emission features probe the stratosphere of the planet and provide information on the carbon-based photochemical processes taking place in that region of the atmosphere. The observations were performed using our cryogenic echelle spectrometer CELESTE, in conjunction with the McMath-Pierce 1.5-m solar telescope between November 1994 and February 1995. We used the methane observations to derive the temperature profile of the jovian atmosphere in the 1-10 mbar region of the stratosphere. This profile was then used in conjunction with height-dependent mixing ratios of each hydrocarbon to determine global abundances for ethane and acetylene. The resulting mixing ratios are 3.9(+1.9)(-1.3) x 10(-6) for C2H6 (5 mbar pressure level), and 2.3 +/- 0.5 x 10(-8) for C2H2 (8 mbar pressure level), where the quoted uncertainties are derived from model variations in the temperature profile which match the methane observation uncertainties. PMID:11878354

  20. Autoradiographic analysis of the in vivo distribution of 3H-imipramine and 3H-desipramine in brain: Comparison to in vitro binding patterns

    SciTech Connect

    Duncan, G.E.; Paul, I.A.; Fassberg, J.B.; Powell, K.R.; Stumpf, W.E.; Breese, G.R. )

    1991-03-01

    Using high resolution autoradiographic techniques, the distribution of radioactivity in forebrain and brainstem was assessed after 4 injection of 3H-impramine or 3H-desipramine. Results were compared with regional binding of the drugs to brain sections in vitro. Similar topographic binding of 3H-imipramine and 3H-desipramine was observed in vitro among brain regions, except in the paraventricular nucleus of the hypothalamus and locus coeruleus, where binding was greater for 3H-desipramine. For both 3H-desipramine and 3H-imipramine, some brain regions that exhibited high binding in vitro also showed high accumulation after in vivo injection. However, certain regions that contained high densities of binding sites for the antidepressant drugs as measured by in vitro binding showed very low accumulation of radioactivity after in vivo treatment. Such regions included the dentate gyrus of the hippocampus, layer 1 of piriform cortex, caudate-putamen, pontine and midbrain central gray, and cerebellar granular layer. Compared to in vitro binding of the drugs, the distribution of imipramine and desipramine in vivo appears more anatomically selective. For imipramine, primary sites of action in vivo, as indicated by the topographic distribution in brain, appear to be the locus coeruleus, hippocampus, lateral septal nucleus, and amygdala. For desipramine, the greatest accumulation in vivo was found in the locus coeruleus, paraventricular nucleus of the hypothalamus, and anterior thalamic nuclei.

  1. Rate constant measurement of the recombination reaction C[sub 3]H[sub 3] + C[sub 3]H[sub 3

    SciTech Connect

    Morter, C.L.; Farhat, S.K.; Adamson, J.D.; Glass, G.P.; Curl, R.F. )

    1994-07-14

    Using the technique of infrared kinetic absorption spectroscopy, the second-order rate constant for the recombination reaction of the propargyl radical (C[sub 3]H[sub 3] + C[sub 3]H[sub 3]) has been measured and found to have the value (1.2 [+-] 0.2) x 10[sup [minus]10] cm[sup 3] molecule[sup [minus]1] s[sup [minus]1] at 295 K. The radical was produced in a flow cell by excimer laser flash photolysis ([lambda] = 193 nm) of the precursors C[sub 3]H[sub 3]Cl or C[sub 3]H[sub 3]Br and detected using time-resolved IR absorption. Absolute concentrations of C[sub 3]H[sub 3] were determined by comparing the C[sub 3]H[sub 3] absorption intensity with that of the Br atom. This calibration scheme was checked by producing methyl radicals by photolysis of methyl bromide and comparing the rate constant for methyl recombination thus obtained with literature values. The quantum yield for HCl production from the photodissociation of C[sub 3]H[sub 3]Cl at 193 nm was determined to be 0.07 [+-] 0.01. 47 refs., 10 figs., 1 tab.

  2. An observational investigation of the identity of B11244 (l-C{sub 3}H{sup +}/C{sub 3}H{sup -})

    SciTech Connect

    McGuire, Brett A.; Carroll, P. Brandon; Gratier, Pierre; Guzmán, Viviana; Pety, Jerome; Roueff, Evelyne; Gerin, Maryvonne; Blake, Geoffrey A.; Remijan, Anthony J.

    2014-03-01

    Pety et al. have reported the detection of eight transitions of a closed-shell, linear molecule (B11244) in observations toward the Horsehead photodissociation region (PDR), which they attribute to the l-C{sub 3}H{sup +} cation. Recent high-level ab initio calculations have called this assignment into question; the anionic C{sub 3}H{sup –} molecule has been suggested as a more likely candidate. Here, we examine observations of the Horsehead PDR, Sgr B2(N), TMC-1, and IRC+10216 in the context of both l-C{sub 3}H{sup +} and C{sub 3}H{sup –}. We find no observational evidence of K{sub a} = 1 lines, which should be present were the carrier indeed C{sub 3}H{sup –}. Additionally, we find a strong anticorrelation between the presence of known molecular anions and B11244 in these regions. Finally, we discuss the formation and destruction chemistry of C{sub 3}H{sup –} in the context of the physical conditions in the regions. Based on these results, we conclude there is little evidence to support the claim that the carrier is C{sub 3}H{sup –}.

  3. A Microporous Metal-Organic Framework with Lewis Basic Nitrogen Sites for High C2H2 Storage and Significantly Enhanced C2H2/CO2 Separation at Ambient Conditions.

    PubMed

    Wen, Hui-Min; Wang, Huizhen; Li, Bin; Cui, Yuanjing; Wang, Hailong; Qian, Guodong; Chen, Banglin

    2016-08-01

    A novel metal-organic framework (MOF), [Cu2L(H2O)2]·7DMF·4H2O [ZJU-40; H4L = 5,5'-(pyrazine-2,5-diyl)diisophthalic acid], with Lewis basic nitrogen sites has been constructed and structurally characterized. Owing to the combined features of high porosity, moderate pore sizes, and immobilized Lewis basic nitrogen sites, the activated ZJU-40a exhibits the second-highest gravimetric C2H2 uptake of 216 cm(3) g(-1) (at 298 K and 1 bar) among all of the reported MOFs so far. This value is not only much higher than that of the isoreticular NOTT-101a (184 cm(3) g(-1)), but also superior to those of two very promising MOFs, known as HKUST-1 (201 cm(3) g(-1)) and Co-MOF-74 (197 cm(3) g(-1)). Interestingly, the immobilized nitrogen sites in ZJU-40a have nearly no effect on the CO2 uptake, so ZJU-40a adsorbs a similar amount of CO2 (87 cm(3) g(-1)) compared with NOTT-101a (84 cm(3) g(-1)) at 298 K and 1 bar. As a result, ZJU-40a shows significantly enhanced adsorption selectivity for C2H2/CO2 separation (17-11.5) at ambient temperature compared to that of NOTT-101a (8-9), leading to a superior MOF material for highly selective C2H2/CO2 separation. PMID:27176900

  4. Nicotinic binding in rat brain: autoradiographic comparison of (/sup 3/H)acetylcholine, (/sup 3/H)nicotine, and (/sup 125/I)-alpha-bungarotoxin

    SciTech Connect

    Clarke, P.B.; Schwartz, R.D.; Paul, S.M.; Pert, C.B.; Pert, A.

    1985-05-01

    Three radioligands have been commonly used to label putative nicotinic cholinoceptors in the mammalian central nervous system: the agonists (/sup 3/H)nicotine and (/sup 3/H)acetylcholine ((/sup 3/H)ACh--in the presence of atropine to block muscarinic receptors), and the snake venom extract, (/sup 125/I)-alpha-bungarotoxin((/sup 125/I)BTX), which acts as a nicotinic antagonist at the neuromuscular junction. Binding studies employing brain homogenates indicate that the regional distributions of both (/sup 3/H)nicotine and (/sup 3/H)ACh differ from that of (/sup 125/I)BTX. The possible relationship between brain sites bound by (/sup 3/H)nicotine and (/sup 3/H)ACh has not been examined directly. The authors have used the technique of autoradiography to produce detailed maps of (/sup 3/H)nicotine, (/sup 3/H)ACh, and (/sup 125/I)BTX labeling; near-adjacent tissue sections were compared at many levels of the rat brain. The maps of high affinity agonist labeling are strikingly concordant, with highest densities in the interpeduncular nucleus, most thalamic nuclei, superior colliculus, medial habenula, presubiculum, cerebral cortex (layers I and III/IV), and the substantia nigra pars compacta/ventral tegmental area. The pattern of (/sup 125/I)BTX binding is strikingly different, the only notable overlap with agonist binding being the cerebral cortex (layer I) and superior colliculus. (/sup 125/I)BTX binding is also dense in the inferior colliculus, cerebral cortex (layer VI), hypothalamus, and hippocampus, but is virtually absent in thalamus. Various lines of evidence suggest that the high affinity agonist-binding sites in brain correspond to nicotinic cholinergic receptors similar to those found at autonomic ganglia; BTX-binding sites may also serve as receptors for nicotine and are possibly related to neuromuscular nicotinic cholinoceptors.

  5. Human pharmacology of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) after repeated doses taken 4 h apart Human pharmacology of MDMA after repeated doses taken 4 h apart.

    PubMed

    Farré, Magí; Tomillero, Angels; Pérez-Mañá, Clara; Yubero, Samanta; Papaseit, Esther; Roset, Pere-Nolasc; Pujadas, Mitona; Torrens, Marta; Camí, Jordi; de la Torre, Rafael

    2015-10-01

    3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a popular psychostimulant, frequently associated with multiple administrations over a short period of time. Repeated administration of MDMA in experimental settings induces tolerance and metabolic inhibition. The aim is to determine the acute pharmacological effects and pharmacokinetics resulting from two consecutive 100mg doses of MDMA separated by 4h. Ten male volunteers participated in a randomized, double-blind, crossover, placebo-controlled trial. The four conditions were placebo plus placebo, placebo plus MDMA, MDMA plus placebo, and MDMA plus MDMA. Outcome variables included pharmacological effects and pharmacokinetic parameters. After a second dose of MDMA, most effects were similar to those after a single dose, despite a doubling of MDMA concentrations (except for systolic blood pressure and reaction time). After repeated MDMA administration, a 2-fold increase was observed in MDMA plasma concentrations. For a simple dose accumulation MDMA and MDA concentrations were higher (+23.1% Cmax and +17.1% AUC for MDMA and +14.2% Cmax and +10.3% AUC for MDA) and HMMA and HMA concentrations lower (-43.3% Cmax and -39.9% AUC for HMMA and -33.2% Cmax and -35.1% AUC for HMA) than expected, probably related to MDMA metabolic autoinhibition. Although MDMA concentrations doubled after the second dose, most pharmacological effects were similar or slightly higher in comparison to the single administration, except for systolic blood pressure and reaction time which were greater than predicted. The pharmacokinetic-effects relationship suggests that when MDMA is administered at a 4h interval there exists a phenomenon of acute tolerance to its effects. PMID:26073279

  6. High affinity binding of [3H]-tyramine in the central nervous system.

    PubMed Central

    Vaccari, A.

    1986-01-01

    Optimum assay conditions for the association of [3H]-para-tyramine [( 3H]-pTA) with rat brain membranes were characterized, and a saturable, reversible, drug-specific, and high affinity binding mechanism for this trace amine was revealed. The binding capacity (Bmax) for [3H]-pTA in the corpus striatum was approximately 30 times higher than that in the cerebellum, with similar dissociation constants (KD). The binding process of [3H]-pTA involved the dopamine system, inasmuch as (a) highest binding capacity was associated with dopamine-rich regions; (b) dopamine and pTA equally displaced specifically bound [3H]-pTA; (c) there was a severe loss in striatal binding capacity for [3H]-pTA and, reportedly, for [3H]-dopamine, following unilateral nigrostriatal lesion; (d) acute in vivo reserpine treatment markedly decreased the density of [3H]-pTA and, reportedly, of [3H]-dopamine binding sites. In competition experiments [3H]-pTA binding sites, though displaying nanomolar affinity for dopamine, revealed micromolar affinities for the dopamine agonists apomorphine and pergolide, and for several dopamine antagonists, while having very high affinity for reserpine, a marker for the catecholamine transporter in synaptic vesicles. The binding process of [3H]-pTA was both energy-dependent (ouabain-sensitive), and ATP-Mg2+-insensitive; furthermore, the potencies of various drugs in competing for [3H]-pTA binding to rat striatal membranes correlated well (r = 0.96) with their reported potencies in inhibiting [3H]-dopamine uptake into striatal synaptosomes. It is concluded that [3H]-pTA binds at a site located on/within synaptic vesicles where it is involved in the transport mechanism of dopamine. PMID:3801770

  7. Regiospecific transfer of tritium into 3H2O from labeled estrogens by mushroom tyrosinase.

    PubMed

    Jellinck, P H; Norton, B; Fishman, J

    1984-10-01

    The specificity of mushroom tyrosinase in displacing 3H from estradiol and catechol estrogens labeled at C-1, C-2, C-4 or C-6,7 was investigated under various conditions. [2-3H]E2 Yielded significant amounts of 3H2O, in the presence of NADH, and the rate of 3H loss from the steroid paralleled that of the radioactivity remaining in the aqueous fraction after extraction with organic solvents. NADH had little effect on the release of 3H from [1-3H]E2 or [4-3H]E2 but glutathione was highly active in this respect, with considerable differences being observed between lyophilizable 3H2O and yields of water-soluble products. It is proposed that 3H losses from C-2 of estradiol reflects oxidative displacement of this isotope by tyrosinase while the loss observed from C-1 and C-4 is the result of non-enzymatic conjugation with glutathione after the formation of the catechol estrogen. The difference between lyophilizable 3H2O and the yield of water-soluble products obtained with [1-3H]E2 and [4-3H]E2 provided a measure of the relative amount of conjugation occurring at C-1 and C-4. These findings were confirmed by double label experiments with 3H- and 14C-labeled estrogens and the isolation of the glutathionyl derivatives. The catechol estrogens did not serve as substrates for further hydroxylation by the enzyme even when C-2 was available for this reaction. These experiments give further information about the specificity of tyrosinase in its reaction with aromatic steroids and provide a simple and rapid method for confirming the distribution of 3H at C-2 or C-4 of estradiol. PMID:6092783

  8. Hydrocalcite (CaCO3 * H2O) and Nesquehonite (MgCO3 * 3H2O) in Carbonate Scales.

    PubMed

    Marschner, H

    1969-09-12

    Hydrocalcite (CaCO(3) * H(2)O) with exactly one molecule of hydrate water is the main component of carbonate scales deposited from cold water in contact with air. When the magnesium content of the water is high, the hydrocalcite occurs together with MgCO(3) * 3H(2)O (nesquehonite). From the conditions under which hydrocalcite is transformed into calcite and aragonite, it appears that in some cases aragonite in nature may be formed by way of an intermediary of CaCO(3) * H(2)O. PMID:17779803

  9. Refractive index and birefringence of 2H silicon carbide

    NASA Technical Reports Server (NTRS)

    Powell, J. A.

    1972-01-01

    The refractive indices of 2H SiC were measured over the wavelength range 435.8 to 650.9 nm by the method of minimum deviation. At the wavelength lambda = 546.1 nm, the ordinary index n sub 0 was 2.6480 and the extraordinary index n sub e was 2.7237. The estimated error (standard deviation) in the measured values is 0.0006 for n sub 0 and 0.0009 for n sub e. The experimental data were curve fitted to the Cauchy equation for the index of refraction as a function of wavelength. The birefringence of 2H SiC was found to vary from 0.0719 at lambda = 650.9 nm to 0.0846 at lambda = 435.8 nm.

  10. Lattice Instability of 2H-TaSe2

    NASA Astrophysics Data System (ADS)

    John Bosco Balaguru, R.; Lawrence, N.; Alfred Cecil Raj, S.

    The charge density wave (CDW) in the layered compound 2H-TaSe2 at low temperatures has a commensurate phase, which causes super lattice points to appear in the Brillöuin zone of the undistorted phase. A Born-von Karman formalism has been employed for the calculation of phonon frequency distribution curves of 2H-TaSe2 both in the normal and in the commensurate charge density wave (CCDW) phases. A folding technique has been adopted for the calculation in the CCDW phase. The phonon distribution for both the phases have been reported. With these distributions the thermal properties such as specific heat capacity, Debye Waller factor W(k) and thermal conductivity have been worked out, and compared with the available experimental results.

  11. C(2)H(4) metabolism in morning glory flowers.

    PubMed

    Beyer, E M; Sundin, O

    1978-06-01

    Flowers of Ipomoea tricolor Cav. (cv. Heavenly Blue) were cut at various stages of development and evaluated for their ability to metabolize ethylene. Freshly cut buds or flowers were treated in glass containers for 8 hours with 6 mul/liter of highly purified (14)C(2)H(4). Following removal of dissolved (14)C(2)H(4), radioactivity was determined for the different flower tissues and trappd CO(2). (14)C(2)H(4) oxidation to (14)CO(2) and tissue incorporation occurred at very low to nondetectable levels 2 to 3 days prior to flower opening. About 1 day prior to full bloom, just at the time when mature buds become responsive to ethylene (Kende and Hanson, Plant Physiol 1976, 57: 523-527), there was a dramatic increase in the capacity of the buds to oxidize (14)C(2)H(4) to (14)CO(2). This activity continued to increase until the flower was fully opened reaching a peak activity of 2,500 dpm per three flowers per 8 hours. It then declined as the flower closed and rapidly senesced. A similar but smaller peak occurred in tissue incorporation and it was followed by a second peak during late flower senescence. This first peak in tissue incorporation and the dramatic peak in ethylene oxidation slightly preceded a large peak of natural ethylene production which accompanied flower senescence. The ethylene metabolism observed was clearly dependent on cellular metabolism and did not involve microorganisms since heat killing destroyed this activity and badly contaminated heat-killed flowers were unable to metabolize ethylene. PMID:16660421

  12. Charge transfer in energetic Li^2+ - H collisions

    NASA Astrophysics Data System (ADS)

    Mancev, I.

    2008-07-01

    The total cross sections for charge transfer in Li^2+ - H collisions have been calculated, using the four-body first Born approximation with correct boundary conditions (CB1-4B) and four-body continuum distorted wave method (CDW-4B) in the energy range 10 - 5000 keV/amu. Present results call for additional experimental data at higher impact energies than presently available.

  13. 2H Evaporator CP class instrumentation uncertainties evaluations

    SciTech Connect

    Hwang, E.

    1994-02-10

    The Evaporator Pot Temperature Instrumentations and the Steam Condensate Gamma Monitors are two instrumentation systems in the 2H Evaporator facilities that are classified as the critical protection. The temperature high alarm and interlock circuit and the temperature recorder circuit of the pot temperature instrumentation loop are described. From the gamma monitor loop, the high gamma alarm and interlock circuit, failure alarm and interlock circuit, cesium activity recorder circuit, and americium activity recorder circuit are described. (GHH)

  14. Diaquabis-(thio-cyanato-κN)bis[6-(4H-1,2,4-triazol-4-yl-κN(1))pyridin-2-amine]-cadmium.

    PubMed

    Liu, Yuan-Yuan; Yang, Pan; Ding, Bin

    2012-08-01

    In the title compound, [Cd(NCS)(2)(C(7)H(7)N(5))(2)(H(2)O)(2)], the Cd(II) cation lies on an inversion center and is coordinated by the N atoms of two thiocyanate anions, by N atoms of two 6-(4H-1,2,4-triazol-4-yl)pyridin-2-amine ligands and by the O atoms of two water molecules in a distorted N(4)O(2) octa-hedral geometry. The dihedral angle between the triazole and pyridine rings is 23.15 (12)°. In the crystal, mol-ecules are linked by N-H⋯N and O-H⋯S hydrogen bonds. Offset π-π stacking between parallel pyridine rings of adjacent mol-ecules is also observed, the centroid-centroid distance being 3.6319 (14) Å. PMID:22904754

  15. Binding of dexetimide and levetimide to ( sup 3 H)(+)pentazocine- and ( sup 3 H)1,3-Di(2-tolyl)guanidine-defined. sigma. recognition sites

    SciTech Connect

    Dehaven-Hudkins, D.L.; Hudkins, R.L. Virginia Commonwealth Univ., Richmond, VA )

    1991-01-01

    The potent antimuscarinic benzetimide and its resolved stereoisomers dexetimide and levetimide were tested for their affinities at {sigma} sites labelled by ({sup 3}H)(+)pentazocine or ({sup 3}H)1,3-di(2-tolyl)guanidine. Levetimide was a potent and stereoselective inhibitor of ({sup 3}H)(+)pentazocine binding, with a K{sub i} of 2.2 nM, while dexetimide was nine-fold less potent (K{sub i} = 19 nM). Dexetimide and levetimide potently inhibited ({sup 3}H)DTG binding although without stereoselectivity (K{sub i} values of 65 and 103 nM, respectively). Levetimide may be a useful tool with which to investigate {sigma} recognition sites and {sigma} subtypes.

  16. Compounds extracted from Phyllantus and Jatropha elliptica inhibit the binding of [3H]glutamate and [3H]GMP-PNP in rat cerebral cortex membrane.

    PubMed

    Martini, L H; Souza, C R; Marques, P B; Calixto, J B; Yunes, R A; Souza, D O

    2000-02-01

    Glutamate is to be considered a nociceptive neurotransmitter and glutamatergic antagonists present antinoceptive activity. In this study we investigated the effects of the naturally occurring antinociceptive compounds rutin, geraniin and quercetine extracted from Phyllanthus, as well as the diterpene jatrophone, extracted from Jatropha elliptica on the binding of [3H]glutamate and [3H]GMP-PNP [a GTP analogue which binds to extracellular site(s), modulating the glutamatergic transmission] in rat brain membrane. Jatrophone inhibited [3H]glutamate binding and geraniin inhibited [3H]GMP-PNP binding. Quercetine inhibited the binding of both ligands. These results may indicate a neurochemical parameter possibly related to the antinoceptive activity of these natural compounds. PMID:10786704

  17. Synthesis ofN-(2-chloro-5-methylthiophenyl)-N'-(3-methyl-thiophenyl)-N'-[3H3]methylguanidine, l brace [3H3]CNS-5161 r brace

    SciTech Connect

    Gibbs, Andrew R.; Morimoto, Hiromi; VanBrocklin, Henry F.; Williams, Philip G.; Biegon, Anat

    2001-09-28

    The preparation of the title compound, [{sup 3}H{sub 3}]CNS-5161, was accomplished in three steps starting with the production of [{sup 3}H{sub 3}]iodomethane (CT{sub 3}I). The intermediate N-[{sup 3}H{sub 3}]methyl-3-(thiomethylphenyl)cyanamide was prepared in 77% yield by the addition of CT{sub 3}I to 3-(thiomethylphenyl)cyanamide, previously treated with sodium hydride. Reaction of this tritiated intermediate with 2-chloro-5-thiomethylaniline hydrochloride formed the guanidine compound [{sup 3}H{sub 3}]CNS-5161. Purification by HPLC gave the desired labeled product in an overall yield of 9% with greater than 96% radiochemical purity and a final specific activity of 66 Ci mmol{sup -1}.

  18. Human platelet dense granules: Improved isolation preliminary characterization of ( sup 3 H)-serotonin uptake and tetrabanazine-displaceable ( sup 3 H)-ketanserin binding

    SciTech Connect

    Chatterjee, D.; Anderson, G.M.; Chakraborty, M.; Cohen, D.J. )

    1990-01-01

    An improved method for the isolation of human platelet dense granules was developed. A good yield of highly enriched dense granules was obtained after mild sonication and Percoll gradient centrifugation. The method has facilitated characterization of the granule, permitting the first report of K{sub m} and V{sub max} values for ({sup 3}H)-serotonin uptake, as well as the first determination of K{sub d} and B{sub max} values for tetrabenazine-displaceable ({sup 3}H)-ketanserin binding, in the human platelet dense granule. The rates and affinities of ({sup 3}H)-serotonin uptake were similar to those previously reported for porcine dense granules. Tetrabenazine-displaceable ({sup 3}H)-ketanserin binding was observed with a K{sub d} similar to, and a B{sub max} approximately 10-fold lower than, that previously seen in bovine chromaffin granules.

  19. Further study on fallout sup 3 H ingestion in Akita, Japan

    SciTech Connect

    Hisamatsu, S.; Takizawa, Y.; Katsumata, T.; Itoh, M.; Ueno, K.; Sakanoue, M. )

    1989-10-01

    To study fallout {sup 3}H ingestion in Japan, 16 separate food-group samples were collected from Akita City in northern Japan during early summer and late autumn in 1986. Furthermore, total diet samples which are duplicate composite food samples consumed by five or six persons for a period of 1 d were also obtained in Akita City. The {sup 3}H concentration in free water and that in a tissue-bound form were determined separately. Seasonal changes of {sup 3}H concentration in the food samples and the total diet samples were not found clearly. The average {sup 3}H concentration in the free water including tap water was 1.6 Bq L-1. The mean ratio of specific activity of tissue-bound {sup 3}H to that of {sup 3}H in free water was found to be 1.2. The average total {sup 3}H ingestion was estimated to be 4.0 Bq d-1, while the proportion of tissue-bound form {sup 3}H ingestion to total {sup 3}H ingestion was 11%. Cereal was the greatest contributing food group to ingestion of tissue-bound {sup 3}H. These findings were consistent with our previous results for food samples collected in 1985.

  20. (3H)bunazosin, a novel selective radioligand of alpha 1 adrenoceptors in human prostates

    SciTech Connect

    Yamada, S.; Suzuki, M.; Matsuoka, Y.; Kato, Y.; Kimura, R.; Maruyama, M.; Kawabe, K. )

    1991-09-01

    The binding properties of a new radioligand, (3H)bunazosin, were studied in membranes of human prostates with benign prostatic hypertrophy (BPH). Specific binding of (3H)bunazosin was saturable, reversible, and of high affinity (Kd = 0.55 {plus minus} 0.04 nM). The density of (3H)bunazosin binding sites (Bmax) was 676 {plus minus} 33 fmol/mg. protein. (3H)Bunazosin rapidly associated with its binding sites in membranes of human prostates and reached steady state by 20 min. at 25C. The rate constants for association and dissociation of (3H)bunazosin binding were calculated to be 0.11 {plus minus} 0.01/nM/min. and 0.05 {plus minus} 0.02/min. (n = 4), respectively. Seven alpha 1 adrenoceptor antagonists competed with (3H)bunazosin for the binding sites in the rank order: R-(-)-YM-12617 greater than prazosin greater than SGB-1534 greater than bunazosin greater than terazosin greater than naftopidil greater than urapidil. In parallel studies with (3H)bunazosin, the Kd and Bmax values for (3H)prazosin binding in human prostates were slightly lower. There was a similarity in the potency and rank order of seven alpha 1, adrenoceptor antagonists for the inhibition of (3H) bunazosin and (3H)prazosin binding in human prostates. The new (3H)bunazosin binding assay in human prostates is remarkable for its low degree of nonspecific binding as compared to (3H)prazosin, especially at high ligand concentrations. Thus, (3H)bunazosin may become a useful radioligand for the further analysis of the alph 1 adrenoceptor binding sites in human prostates.