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  • Solar Physics  (9)
  • Chemistry  (4)
  • Computational Chemistry and Molecular Modeling  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Peroxidase and laccase as catalysts for removal of the phenylhydrazide protecting group under mild conditions (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 1137-1141 
    Details
    ISSN: 0006-3592
    Keywords: peroxidase ; laccase ; phenylhydrazide protecting group ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new method is proposed for the removal of the phenylhydrazide protecting group by the action of peroxidase or laccase, the enzymes attributed to the class of oxidoreductases. The deblocking procedure is performed under mild oxidative conditions, i.e., aqueous solution and neutral or close to neutral pH. Such mild oxidizing agents as 1 mM H2O2 and air oxygen are used for unmasking. The method is available for the deblocking of both α- and γ-carboxyl groups. The enzyme-catalyzed removal of the phenylhydrazide protecting group causes no oxidative modification nor destruction of methionine or tryptophan side chains. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260421002
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  • 2
    Electronic Resource
    Electronic Resource
    Variational principle for transition matrix (1993)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 45 (1993), S. 71-85 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A variational principle for the transition matrix is considered. Conception of the MC SCF (in particular, CASSCF) approach for the transition matrix is proposed as a solution of the variational problem on the optimal evolution of a packet of two stationary states with some additional conditions. An ordinary MC SCF method for a single state is a special case of the proposed approach. Some aspects of the solving of the equations for the optimal transition matrix are treated. The method can be used in atomic and molecular calculations of transition energies, oscillator strengths, and other properties. © 1993 John Wiley & Sons, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560450110
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  • 3
    Electronic Resource
    Electronic Resource
    Untersuchungen zum System Te/O/Br (1978)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 439 (1978), S. 13-28 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on the System Te/O/BrThe melting point diagram of the system TeBr4—TeO2 was obtained by total pressure measurements and DTA measurements. A Congruent melting composition Te6O11Br2 exists, the melting point is 570°C.The enthalpy of formation and the standard entropy of the species TeOBr2,g was derived from measurements of the total pressure over Te6O11Br2/TeBr4 and from the transport behaviour of the TeO2 with Br2.From the decomposition-pressure measurements over Te6O11Br2/TeO2 follow the partial pressure.The enthalpy of formation ΔH°(Te6O11Br2,f,298) = -453.5 kcal/Mol was obtained from the enthalpy of solution. The transport-behaviour of TeO2 with HBr, with Tebr4 and Br2 and that of Te6O11Br2 is clear with the thermodynamic data of TeObr2.
    Notes: Das Schmelzdiagramm des Systems TeO2—TeBr4 wurde durch Dampfdruckmessungen und DTA ermittelt. Im System existiert eine bei 570°C kongruent schmelzende Verbindung Te6O11Br2Aus Dampfdruckmessungen über Te6O11Br2/TeBr4 und Messung des Gesamtdruckes TeO2,f/Br2,g sowie der Auswertung des Transportverhaltens des TeO2 mit Br2 wurden die Bildungsenthalpie und die Standardentropie der Gasphasenspezies TeOBr2 abgeleitet. Aus den Zersetzungsdruckmessungen über Te6O11Br2/TeO2 folgen die Partialzersetzungsdrucke.Lösungscalorimetrisch wurde die Bildungsenthalpie ΔH0(Te6O11Br2,f,298) = -453,5 kcal/Mol ermittelt.Das Transportverhalten von TeO2 mit HBr, TeBr4 und Br2, sowie das des Te6O11Br2 ist mit den thermodynamischen Daten des TeOBr2 verständlich und beschreibbar.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19784390102
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  • 4
    Electronic Resource
    Electronic Resource
    Matrix elements of the U(2n) generators in the spin-orbit basis (1992)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 42 (1992), S. 1711-1716 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An algorithm for the evaluation of the matrix elements of the U(2n) generators in the spin-orbit basis [induced by the U(n) ⊗ U(2) subgroup] is proposed. This algorithm can be used for calculations with spin-dependent Hamiltonians for many-electron problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560420609
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  • 5
    Electronic Resource
    Electronic Resource
    A two-step method of calculation of the electronic structure of molecules with heavy atoms: Theoretical aspect (1996)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 57 (1996), S. 453-463 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An approach for a space-separated calculation of the wave function in the valence and core regions of a molecule is proposed. As the first step, the calculation of the orbitals (or two-component spinors in the relativistic case) in the valence region by the effective core potential (ECP) method is performed. Then, it is followed by a restoration of orbitals (four-component spinors) expanded on spherical harmonics in the core regions of heavy atoms. Theoretical questions of the variational calculation of the molecular orbitals are considered in some core region limited by a sphere. Inclusion from the electronic cloud outside this region is reduced by the necessity of taking into account the orthonormality and boundary conditions together with an effective external field in respect to the selected core region.This method may be used for calculation of matrix elements of operators that are singular near nuclei (P, T-odd interactions, hyperfine structure, etc.). A substantial computational saving can be reached because the method enables, by the most optimal way, to combine the advantages of two well-developed approaches: molecular ECP calculations in the Gaussian basis set and one-center numerical atomic calculations with an external field. It is especially important when the relativistic effects are taken into account. © 1996 John Wiley & Sons, Inc.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Generalized relativistic effective core potential: Gaussian expansions of potentials and pseudospinors for atoms Hg through Rn (1997)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 63 (1997), S. 1107-1122 
    Details
    ISSN: 0020-7608
    Keywords: relativistic pseudopotentials ; heavy atoms ; method of molecular calculation ; electronic structure ; Gaussian approximation ; Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Gaussian expansions of the generalized relativistic effective core potential (GRECP) components are reported for elements Hg through Rn. The accuracy of the analytical GRECPs is estimated by calculations of atomic transition energies with the numerical one-configurational wave functions in comparison with Dirac-Fock calculations. The results of the corresponding calculations with the RECPs of other groups are also given. An “averaged error” in the reproduction of the transition energies without the change of the occupation number of the 5d-shell is an order of magnitude smaller than that for the RECPs of other groups. As is demonstrated for the transitions with the change of the occupation number of the 5d-shell in mercury, the largest absolute error of the GRECP is only 1.5-2 times smaller than that of the energy-adjusted pseudopotential (PP) or the RECP of Ross et al. with the same space of explicitly treated electrons. However, the dispersion of these errors is 19⋅10-4 au for the energy-adjusted PP, 35⋅10-4 au for the RECP of Ross et al. and only 4⋅10-4 au for the GRECP. One-configurational spin-averaged calculations of the molecular properties for HgH and HgH+ are carried out and compared with the corresponding results of Häussermann et al.   © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 1107-1122, 1997
    Additional Material: 17 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    The Use of Intermediates with Preformed Disulfide Bridge for the Synthesis of Oxytocin and Deamino-oxytocin (1972)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 55 (1972), S. 2854-2860 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The disulfide-bridged hexapeptides 6a and 6b have been prepared from benzyl-protected intermediates. Coupling of 6a and 6b with prolyl-leucyl-glycine amide afforded deamino-oxytocin (7a) and the protected oxytocin derivative 7b, respectively; the latter was converted to oxytocin (7c) by removal of the Boc protecting group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19720550817
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  • 8
    Electronic Resource
    Electronic Resource
    Novel bis(napthalic anhydrides) and polyheteroarylenes on their basis (1988)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 39 (1988), S. 460-464 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine Reihe neuer Bis(naphthalincarbonsäureanhydride) wurden durch Umsatz von Acenaphthen mit Dichloranhydriden von Dicarbonsäuren unter den Bedingungen einer Friedel-Crafts-Reaktion mit Chloral bzw. Bromal und nachfolgender Oxidation der Bis(acenaphthyle) und Anhydridisierung der Tetracarbonsäuren synthetisiert. Aus diesen Anhydriden und Bis(o-phenylendiaminen) erhaltene Poly(naphthoylen-benzoimidazole) vereinen gute thermische Eigenschaften mit Löslichkeit in organischen Lösungsmitteln.
    Notes: A series of novel bis(naphthalic anhydrides) has been prepared through acenapthene interaction with the dichloroanhydrides of dicarboxylic acids under the conditions of the Friedel-Crafts reaction or with chloral and bromal followed by oxidation of bis-acenaphthyls and anhydrization of the tetracarboxylic acids synthesized. Poly(naphthoylene benzoimidazoles) combining advantageous thermal properties and solubility in organic solvents have been obtained through interaction between the synthesized anhydrides and bis(o-phenylene diamines).
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1988.010390818
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  • 9
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    A Model for the Sources of the Slow Solar Wind (2010)
    In:  CASI
    Details
    Publication Date: 2018-06-06
    Description: Models for the origin of the slow solar wind must account for two seemingly contradictory observations: The slow wind has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow wind has large angular width, up to approximately 60 degrees, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow wind at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far front the heliospheric current sheet. We then use an MHD code and MIDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady solar wind and magnetic field for a time period preceding the August 1, 2008 total solar eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow wind. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere, and propose further tests of the model.
    Keywords: Solar Physics
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    NASA TECHNICAL REPORTS
  • 10
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    The Evolution of Open Magnetic Flux Driven by Photospheric Dynamics (2010)
    In:  CASI
    Details
    Publication Date: 2018-06-06
    Description: The coronal magnetic field is of paramount importance in solar and heliospheric physics. Two profoundly different views of the coronal magnetic field have emerged. In quasi-steady models, the predominant source of open magnetic field is in coronal holes. In contrast, in the interchange model, the open magnetic flux is conserved, and the coronal magnetic field can only respond to the photospheric evolution via interchange reconnection. In this view the open magnetic flux diffuses through the closed, streamer belt fields, and substantial open flux is present in the streamer belt during solar minimum. However, Antiochos and co-workers, in the form of a conjecture, argued that truly isolated open flux cannot exist in a configuration with one heliospheric current sheet (HCS) - it will connect via narrow corridors to the polar coronal hole of the same polarity. This contradicts the requirements of the interchange model. We have performed an MHD simulation of the solar corona up to 20R solar to test both the interchange model and the Antiochos conjecture. We use a synoptic map for Carrington Rotation 1913 as the boundary condition for the model, with two small bipoles introduced into the region where a positive polarity extended coronal hole forms. We introduce flows at the photospheric boundary surface to see if open flux associated with the bipoles can be moved into the closed-field region. Interchange reconnection does occur in response to these motions. However, we find that the open magnetic flux cannot be simply injected into closed-field regions - the flux eventually closes down and disconnected flux is created. Flux either opens or closes, as required, to maintain topologically distinct open and closed field regions, with no indiscriminate mixing of the two. The early evolution conforms to the Antiochos conjecture in that a narrow corridor of open flux connects the portion of the coronal hole that is nearly detached by one of the bipoles. In the later evolution, a detached coronal hole forms, in apparent violation of the Antiochos conjecture. Further investigation reveals that this detached coronal hole is actually linked to the extended coronal hole by a separatrix footprint on the photosphere of zero width. Therefore, the essential idea of the conjecture is preserved, if we modify it to state that coronal holes in the same polarity region are always linked, either by finite width corridors or separatrix footprints. The implications of these results for interchange reconnection and the sources of the slow solar wind are briefly discussed.
    Keywords: Solar Physics
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