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1.
Condeixa Lucas Dias Silva Pierry Moah Diego Farias Brenda Leiras Adriana 《Central European Journal of Operations Research》2022,30(3):921-940
Central European Journal of Operations Research - Societal awareness and legislation changes concerning sustainability have affected how organizations generate value for stakeholders, as well as... 相似文献
2.
Arthur G. Maki John C. Grecu Brenda Winnewisser Manfred Winnewisser 《Journal of Molecular Spectroscopy》2003,222(2):198-212
High-resolution spectra of 15N12C12C15N and 14N13C13C14N have been measured and analyzed from 200 to 3600 cm−1. All the vibrational levels below 900 cm−1 have been observed and characterized. The Fermi resonance between ν2 and 2ν4 has been studied and the resonance constant has been determined for several cases. Several Σ− states have been directly observed for the first time for each isotopomer, the (0001111)0f, (0011111)0f, and (0002222)0f states. The pattern of the energy levels for clusters of l-type resonance coupled levels, such as 0001131,3, has been determined for cyanogen for the first time. Among other things this involved the determination of the vibrational l-type resonance constant, r45. Many of the power series constants, αi and xij, and higher order constants have been determined. 相似文献
3.
Brenda J. Latka 《Journal of Graph Theory》2003,42(3):165-192
A finite tournament T is tight if the class of finite tournaments omitting T is well‐quasi‐ordered. We show here that a certain tournament N5 on five vertices is tight. This is one of the main steps in an exact classification of the tight tournaments, as explained in [10]; the third and final step is carried out in [11]. The proof involves an encoding of the indecomposable tournaments omitting N5 by a finite alphabet, followed by an application of Kruskal's Tree Theorem. This problem arises in model theory and in computational complexity in a more general form, which remains open: the problem is to give an effective criterion for a finite set {T1,…,Tk} of finite tournaments to be tight in the sense that the class of all finite tournaments omitting each of T1,…,Tk is well‐quasi‐ordered. © 2003 Wiley Periodicals, Inc. J Graph Theory 42: 165–192, 2003 相似文献
4.
Ghandi K Addison-Jones B Brodovitch JC McCollum BM McKenzie I Percival PW 《Journal of the American Chemical Society》2003,125(32):9594-9595
Muoniated free radicals have been detected in muon-irradiated aqueous solutions of acetone at high temperatures and pressures. At temperatures below 250 degrees C, the radical product is consistent with muonium addition to the keto form of acetone. However, at higher temperatures, a different radical was detected, which is attributed to muonium addition to the enol form. Muon hyperfine coupling constants have been determined for both radicals over a wide range of temperatures, significantly extending the range of conditions under which these radicals and the keto-enol equilibrium have been studied. 相似文献
5.
Guy Guelachvili K. Narahari Rao Richard H. Tipping Brenda P. Winnewisser Manfred Winnewisser 《Mikrochimica acta》1988,95(1-6):339-343
This paper reports the observation of the far infrared absorption spectrum of a single crystal of N2, measured over absorption paths of 4 cm (lengthwise) and 2 cm (across the crystal). The crystal chamber, with quartz windows, was immersed in a flow of cold helium gas. The spectrum from 20 to 120 cm–1 was recorded in the liquid phase, the-phase, and over the full temperature range of the-phase (35.6–2.0 K) with a Fourier transform spectrometer. The spectral resolution, which was not instrument-limited, and the large path allowed the observation of more detailed multiphonon-transition structure in the spectrum of the-phase than has previously been observed. 相似文献
6.
Brenda J. Postnikova 《Tetrahedron letters》2004,45(3):501-504
C3-Symmetric chiral receptors have been developed for enantioselective alkylation of sodium enolates of active methylene compounds. It has been demonstrated that a 1:1 binding complex forms between these receptors and sodium enolates in THF-d8/CD3CN by 1H NMR titration experiments. Moderate enantiomeric enrichment of the benzylation product of 2-acetylcyclohexanone has been demonstrated using this strategy. Templation of enolate alkylation by synthetic receptors represents a new approach to asymmetric induction. 相似文献
7.
Feng Ji Paul W. Percival Jean-Claude Brodovitch Brenda Addison-Jones Stanislaw Wlodek 《Hyperfine Interactions》1994,87(1):853-858
Muonium adds to allyl chloride, CH2=CHCH2Cl, to form two radicals: MuCH2CHCH2Cl (main product) and CH2CHMuCH2Cl (minor product). Both radicals were fully characterized bySR andLCR. In the main product, the LCR lines due to the35Cl and37Cl nuclei were observed. Also, the temperature dependence of various hyperfine coupling constants (hfc) indicates that both Mu and Cl eclipse the unpaired electronp
2-orbital in the minimum energy conformation. For the fragment-CH2Cl, the presence of Mu in the-position is found to affect significantly the hfc of Cl in the-position; an internal rotational barrier of 12 kJ mol–1 was estimated using a simpleV
2 torsional potential. 相似文献
8.
A trinuclear heterobimetallic Ru(II)/Pt(II) complex, cis-{Ru(phen)2[CN-Pt(DMSO)Cl2]2} (phen = 1,10-phenanthroline), is able to function as a "switch-on" luminescent chemodosimeter for sulfhydryl-containing amino acids and peptides via specific binding of the amino acids/peptides with the Pt(II) centers and the subsequent cleavage of the Ru(II)-Pt(II) cyano-bridge. 相似文献
9.
Kanda S. Ramasamy Farid Bakir Brenda Baker P. Dan Cook 《Journal of heterocyclic chemistry》1993,30(5):1373-1377
The synthesis of benzylated N2-(4,7,10,13-tetraazatridec-1-yl)-2′-deoxyguanosines 4 was accomplished by a key nucleophilic reaction of the novel unsymmetrical polyamine 2 , with 3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-2-chloro-2′-deoxyinosine ( 1 ). 相似文献
10.
Getahun Z Huang CY Wang T De León B DeGrado WF Gai F 《Journal of the American Chemical Society》2003,125(2):405-411
It is well-known that the C=N stretching vibration in acetonitrile is sensitive to solvent. Therefore, we proposed in this contribution to use this vibrational mode to report local environment of a particular amino acid in proteins or local environmental changes upon binding or folding. We have studied the solvent-induced frequency shift of two nitrile-derivatized amino acids, which are, AlaCN and PheCN, in H(2)O and tetrahydrofuran (THF), respectively. Here, THF was used to approximate a protein's hydrophobic interior because of its low dielectric constant. As expected, the C=N stretching vibrations of both AlaCN and PheCN shift as much as approximately 10 cm(-1) toward higher frequency when THF was replaced with H2O, indicative of the sensitivity of this vibration to solvation. To further test the utility of nitrile-derivatized amino acids as probes of the environment within a peptide, we have studied the binding between calmodulin (CaM) and a peptide from the CaM binding domain of skeletal muscle myosin light chain kinase (MLCK(579-595)), which contains a single PheCN. MLCK(579-595) binds to CaM in a helical conformation. When the PheCN was substituted on the polar side of the helix, which was partially exposed to water, the C=N stretching vibration is similar to that of PheCN in water. In constrast, when PheCN is introduced at a site that becomes buried in the interior of the protein, the C=N stretch is similar to that of PheCN in THF. Together, these results suggest that the C=N stretching vibration of nitrile-derivatized amino acids can indeed be used as local internal environmental markers, especially for protein conformational studies. 相似文献