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  • Electronic Resource  (1,715)
  • 1985-1989  (1,715)
  • Atomic, Molecular and Optical Physics  (1,119)
  • Life Sciences (general)  (596)
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  • Electronic Resource  (1,715)
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  • 101
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 225-240 
    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: Analytical and numerical studies are performed concerning the exclusion of the basis set superposition error (BSSE) from the SCF calculations of intermolecular interactions. Based on these studies a new procedure is proposed, which consists of the following steps: (1) determine the orbitals by the SCF scheme based on the recent “chemical Hamiltonian approach” (CHA-SCF method), i.e., excluding the delocalization effects caused by BSSE, and then (2) calculate the usual energy expectation value. (This gives results superior to those obtained by the previous nonsymmetric CHA energy formula.) The actual numerical calculations performed for different simple systems (He2, water dimer) by using various basis sets indicate that the CHA/CE (CHA with “conventional energy” formula) potential curves are well-balanced and are close to those obtained by the Boys-Bernardi (BB) method and usually (but not necessarily) go slightly beyond the latter. So our method gives results better than (or close to) those given by the BB method by performing only a single ∼N4 calculation at each geometrical arrangement of the system.
    Additional Material: 2 Ill.
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  • 102
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 277-285 
    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: The effect of electron correlation on the results of pseudopotential calculations was examined using a simple analytical semiempirical pseudopotential and a correlated floating-type one-center wave function. Investigations were performed for the XH alkali metal hydride molecules (X = Na, K, Rb, Cs). The inclusion of the electron correlation in the ground state proved important for the calculation of the dissociation and ionization energies, but it is less significant for the determination of the equilibrium nuclear distances. The ground state potential energy curves are also determined.
    Additional Material: 4 Tab.
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  • 103
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 241-253 
    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: Ab initio molecular orbital methods are employed to study the low-lying states of C3H+, SiC2H+, Si2CH+, and Si3H+. Special attention is paid to a comparative study between C3H+ and Si3H+. In both cases a 3B2 state is found to lie the lowest at the HF level, although inclusion of correlation effects favor a linear structure (1Σ+ state) for C3H+, which lies 25 kcal/mol below the 3B2 state at the MP4 level, and a bent structure (1A′ state) for Si3H+, which lies just 2 kcal/mol below the 3B2 state. The proton affinities of C3, SiC2, Si2C, and Si3 are estimated at different levels of theory. Both protonation at carbon and silicon atoms are considered for SiC2 and Si2C. It is found that C3 comparatively has a low proton affinity. On the other hand, Si3 has a relatively high proton affinity compared with the protonation at silicon atom for both SiC2 and Si2C. These results are discussed on the basis of electronic structure arguments.
    Additional Material: 5 Ill.
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  • 104
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 287-298 
    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 empirical potential is introduced that is suitable for calculation of the interaction enegies of biomolecules with thousands of atoms. The potential consists of electrostatic, repulsion, and dispersion energy terms. The approach used for parametrization of the potential is entirely different from that used with other existing potentials. Namely, all the terms were parametrized independently to retain their physical significance. The sum of the electrostatic and repulsion terms mimic the SCF interaction energy calculated using Huzinaga's minimal basis set MINI-1. The dispersion energy is very important and is usually predominant for the interactions of large (polar) molecules in the gas phase as well as in the liquid phase.
    Additional Material: 6 Ill.
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  • 105
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 201-211 
    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: In this paper a general method for the evaluation of the matrix elements of spin-dependent operators is proposed to improve the treatment primitively suggesteed by Cooper and Musher. This approach is largely based on the recent results which the present authors have achieved in the representation theory for the inner- and outer-product reduction of the symmetric group. It is shown that the so-called outer-product coupling coefficients (OPCC) can be used to generalize the method for constructing the irreducible tensor operators of group Sn. Together with the use of inner-product coupling coefficients (IPCC), an expression for the matrix elements of spin-dependent operators is presented as the product of a Racah coefficient for Sn and a reduced matrix element which can be expressed in terms of IPCC, OPCC, and the related integrals. The treatment for one- and two-electron spin-dependent operators is discussed in detail.
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  • 106
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 255-263 
    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: The isotropic (aiso) and dipolar (Adip) hyperfine coupling constants of 19F2- were obtained from MRD-CI wave functions using a variety of basis sets. In series I, increasing numbers of d functions were added to a 5s4p contracted Huzinaga/Dunning basis. In series II, the 5s3p basis set was uncontracted in several steps until 9s5p was reached, to which were added from one to three d-polarization functions. CI parameters (selection thresholds and the number of reference configurations) were also varied. A study of the R dependence of aiso and Adip was performed. The best values obtained at Re are 260 G for aiso and 308 G for Adip, compared with experimental values of about 280 G for aiso and 320 G for Adip.
    Additional Material: 8 Tab.
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  • 107
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 299-312 
    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: Quantum mechanical calculations have been used to study the reaction mechanism of human carbonic anhydrase-catalyzed hydration of CO2. This reaction is responsible for fast metabolism of CO2 in the human body. For each of the reaction steps, possible catalytic effects of active site residues are examined. The pertinent results are as follows. (1) For CO2 binding, the experimentally observed 2.5 cm-1 frequency shift of the asymmetic stretching frequency between measurements taken in the aqueous solution and in the enzyme is reproduced in our theoretical calculations. Our results suggest that CO2 binds to the zinc ion within the hydrophobic pocket. (2) No energy barrier is found for the nucleophilic attack from Zn2+-bound OH- to C of CO2 to form Zn2+-bound HCO3-. (3) For the internal proton transfer within zinc-bound HCO3-, the barrier of 35.6 kcal/mol for the direct internal proton transfer is reduced to 3.5 and 1.4 kcal/mol, respectively, when one or two water molecules are included for proton relay. (4) Displacement of Zn2+-bound HCO3- by H2O is facilitated by the presence of the negatively charged Glu 106-Thr 199 chain and by the association and the subsequent ionization of a fifth water ligand. (5) For the intramolecular proton transfer between Zn2+-bound H2O and His 64, the Zn2+ ion lowers the pKa of Zn2+-bound water and repels the proton. His 64, or a similar proton receptor with a larger proton affinity than H2O, functions as proton receiver; and the active site water molecules visualized by x-ray crystallography are important for the proton relay function. In summary, it is demonstrated that in order to achieve effective catalysis, a sequence of precisely coordinated catalytic events among all participating catalytic elements in the enzyme's active site is essential.
    Additional Material: 6 Ill.
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  • 108
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 325-339 
    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: We describe an efficient new algorithm which extends the range of feasible shell model calculations. This algorithm is applicable to single shell and multiple shell configurations, where two or more quantum numbers (e.g., L and S) are required to label the states within each shell. The algorithm proceeds by factoring the shell model Hilbert space into a product of subspaces, one for each angular momentum. N-particle wave functions are built up recursively from N - 1 particle wave functions. Three kinds of N - 1- to N-particle coefficients are required to carry out the construction of N-particle electron (or fermion) states from N - 1 particle states. These are (1) coefficients of fractional parentage (CFPs) within a single shell, (2) outerproduct isoscalar factors (OISFs) within a single angular momentum subspace, and (3) innerproduct isoscalar factors (IISFs) which describe how multishell states within the complementary angular momentum subspaces are combined to form totally antisymmetric wave functions. All three types of N - 1- to N-particle coefficients are generated recursively using a single powerful and efficient matrix diagonalization algorithm. Matrix elements of single particle creation and annihilation operators are expressed in terms of single particle CFPs, OISFs, and IISFs. We also describe an efficient algorithm for computing matrix elements of products of creation and anihilation operators by inserting and summing over complete sets of intermediate states. This is the Feynman-like sum over path overlaps procedure. Timing benchmarks are presented comparing the new Drexel University shell model (DUSM) code with a state of the art shell model code.
    Additional Material: 7 Ill.
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  • 109
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 791-791 
    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
    Type of Medium: Electronic Resource
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  • 110
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 503-524 
    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 graphical approach to the configuration interaction in the basis of pure Slater determinants is presented. The formulation based on the spin-separated two-slope graph (SSTSG), enabling the selection of determinants with the fixed Ms value, has a direct relation to the well-known concept of the group-function product. The commonly used excitation criterion and the spatial (Abelian) symmetry properties are analyzed in terms of the graph's internal structure. The Slater formulae for the Hamiltonian matrix elements between determinants, in the particle-hole formalism and in the spin-separated form, are related to different classes of loops within graphs. Some aspects of implementation within both the matrix-element-driven (ME) and integral driven (ID, direct) CI algorithms are discussed. The presented formulation, of a general complete active space (CAS) CI type, is a basis of the Graphical Determinantal Configuration Interaction (GDCI) computer program.
    Additional Material: 10 Ill.
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  • 111
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    International Journal of Quantum Chemistry 36 (1989), S. 535-535 
    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
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  • 112
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989) 
    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
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  • 113
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 575-586 
    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 complex multidimensional DNA structure is obtained when treating the elements of the Eco RI restriction set of buffalo rat as a cascade of self-similar units. Fifteen of the 16 (about 94%) Eco RI repeat families, ranging in length from 2300 to 83 nucleotides and in frequency from 500 to 〉 106 units, are sorted into a three-tiered well-ordered fractal/Fibonacci lattice. On the first level, 11 fractal dimensions are defined as unique collinear collections of repeat DNA families in a “graph-invariant” plot of log(fragment length):log(frequency). On the second level, the individual dimensional arrays are clustered as groups, each sharing, at last, one common vertex. On the third level, the entire display is scaled along a stepwise log to the base 6 expansion. This study represents the first successful attempt to unify an “entire” set of repeat DNAs into a single motif, in effect confirming the contention that select repeat DNAs provide a framework for the discrete packaging and unpackaging of genomic information.
    Additional Material: 2 Ill.
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  • 114
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 765-771 
    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: Vibrational and vibration-rotational energy levels of ozone and its isotopic substitutes have been calculated variationally by the ladder operator method. Thirty vibrational band origins and rotational energies of vibrational ground states for these molecules have been given. The good agreement between the calculated results and the observed values shows that the calculation method is a promising one for variational studies of vibrational and vibration-rotational properties of nonlinear polyatomic molecules.
    Additional Material: 7 Tab.
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  • 115
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 741-748 
    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: Earlier work on the Pauli potential VPauli, which allows the square root of the electron density to be calculated directly from a Schrödinger equation, is generalized from two-level (radial) systems such as the Be atom to the n-level case in one dimension. This is achieved using hyperspherical functions, in terms of which the first- and second-order density matrices are expressed. It is confirmed that VPauli can be constructed from the ground-state density ρ (x) and its first two derivatives, plus the functional derivative of the single-particle kinetic energy with respect to ρ. Finally, contact is made with the Harriman construction, but now using approximate one-body orbitals.
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  • 116
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 35 (1989), S. 1-1 
    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
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  • 117
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    International Journal of Quantum Chemistry 35 (1989), S. 103-112 
    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: Results of a Monte Carlo simulation of the hydration of caffeine (1,3,7-trimethyl-2,6-dioxipurine) and three different configurations of its stacked dimer are presented. Simulations were performed in a cluster approximation; the system contained 200 water molecules. The nature of the stabilization of caffeine stacking associates in water was considered. A hydrophobic behavior of methyl groups during association of caffeine molecules in water is shown. Results of the simulation of caffeine hydration are compared with experimental data from the study of the system of caffeine-water.
    Additional Material: 5 Ill.
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  • 118
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    International Journal of Quantum Chemistry 35 (1989), S. 125-139 
    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 close scrutiny of the relationship between geometric constraints and motion in a system of water molecules allows the prediction of a role of solvent dynamics in the solvent-mediated interaction between two solutes and between different parts of one solute. The predicted mechanism is cooperative, and its operation is widely supported by experiments (not only by our group) in which solvent dynamics were modulated by isotopic or cosolvent perturbations. More recent experimental work by our group and simulation work of MCY water by Fornili et al, strengthens this evidence and visualizes how an immobilized water molecule can “seed” or “pin” a high-connectivity patch of H bonds. Involvement of the mechanism in pattern-specific, solvent-mediated driving forces of significant size (additional to those due to electrostatic recognition determinants) and in functional proton-transfer is inferred from available evidence.
    Additional Material: 7 Ill.
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  • 119
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    International Journal of Quantum Chemistry 35 (1989), S. 205-214 
    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: Ab initio, quantum chemical methods have been used to develop an interaction model for the binding of benzoic and salicylic acids and phenols to cyclooxygenase, leading to their antiinflammatory action. The model is based on a regression analysis of the energy of the highest occupied molecular orbital with the potency of the active substances to inhibit prostaglandin production in mouse macrophages and on an analysis of the frontier orbital charge distributions and electrostatic potentials of active and inactive compounds. The model suggests that binding is controlled by an electrostatic orientational factor and a charge transfer or polarization contribution. The observed relative potencies of the phenols and acids can be rationalized with the help of the proposed interaction model.
    Additional Material: 4 Ill.
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  • 120
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    International Journal of Quantum Chemistry 35 (1989), S. 253-253 
    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
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  • 121
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 35 (1989) 
    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
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  • 122
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    International Journal of Quantum Chemistry 35 (1989), S. 215-221 
    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
    Additional Material: 3 Ill.
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  • 123
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    International Journal of Quantum Chemistry 35 (1989), S. 241-252 
    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
    Additional Material: 4 Ill.
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  • 124
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    International Journal of Quantum Chemistry 35 (1989), S. 257-266 
    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: Wave function tails are analyzed quantitatively by investigating the dependence of exterior electron density (EED) on basis sets; the EED is defined as the integrated electron density outside the repulsive molecular surface. Ab initio MO calculations with large scale basis sets were performed to establish the benchmark order of EED values for valence orbitals of some simple molecules. It is found that very popular basis sets, such as 4-31G, which are determined by energy optimization, are inferior in describing the wave function tails to some similar size basis sets, such as MIDI-4, which are obtained by least-squares fit to near Hartree-Fock atomic functions. Further the EED values for atomic 2s functions are shown to be unfavorably smaller than those for atomic 2p functions when the same value is used for the exponent α in the GTO basis sets. This indicates that the frequently used constraint αs = αp is not appropriate for describing wave function tails with medium-size basis sets. Deficiencies in the energy-optimized basis sets are found to become more serious for molecules including heavier atoms.
    Additional Material: 1 Ill.
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  • 125
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    International Journal of Quantum Chemistry 35 (1989), S. 359-359 
    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
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  • 126
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    International Journal of Quantum Chemistry 35 (1989), S. 385-393 
    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: Double-well potential energy surfaces for hydrogen bonding in crystalline vitamin B6 have been associated with molecular environmental effects. New calculations, involving improved representations of a fragmentation model, include the introduction of a second pyridoxinium chloride system within the model in a “dimer-like” configuration. The new results confirm the double-well potential and the prediction of the experimentally observed position for the proton as being due essentially to environmental effects.Atomic difference maps are presented for the charge density distributions, which reflect the nature of the bonding as it depends on the proton position. Mulliken populations are examined particularly in relation to the “intermolecular” transfer of electrons.
    Additional Material: 5 Ill.
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  • 127
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    International Journal of Quantum Chemistry 35 (1989), S. 425-432 
    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: One of possible approaches to the CI method is based on Boys bonded functions which can be generated in a systematic way forming an independent set of high internal symmetry. The main disadvantage of bonded functions is their nonorthogonality. In this paper a scheme is proposed for passing to orthogonalized set of bonded functions together with the appropriate algorithm for the transformation of the energy matrix H. The orthogonalization matrices are shown to reflect high symmetry of the canonical set of bonded functions, and in what follows they can be defined by short vectors. Moreover, the orthogonalization transformation can be handled in a blockwise manner.
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  • 128
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    International Journal of Quantum Chemistry 35 (1989), S. 459-459 
    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
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  • 129
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    International Journal of Quantum Chemistry 35 (1989), S. 471-481 
    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 interaction range analysis of electronic structures has been developed with density matrix approximation techniques. A successive error analysis of electronic interaction of differing ranges reveals clear pattrns. Aromatic hydrocarbons and heterocycles are used as examples. The developed technique is proposed to be used as an illustrative tool for the description of delocalization and as a guide for studies where delocalized systems are modeled by small subsystems.
    Additional Material: 6 Ill.
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  • 130
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    International Journal of Quantum Chemistry 35 (1989), S. 551-566 
    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: The explicit formulas for the evaluation of the Hamiltonian matrix elements are presented. The calculation of the integral coefficients is independent of both the nature of the orbitals and th spin coupling schemes. It is fully automatic and only dependent on the number of doubly and singly occupied orbitals. Further-more, the symmetric group representation matrices are not needed, and the N! problem can be avoided.
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  • 131
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    International Journal of Quantum Chemistry 35 (1989), S. 581-581 
    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
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  • 132
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    International Journal of Quantum Chemistry 35 (1989), S. 593-612 
    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 practical method for generating irreducible matrix reps of point groups and a concise formula about projection operators are proposed. By using this formula as well as versatile classification schemes, the symmetry adaptation of a many-electron system is simplified. A unified algorithm and program of symmetry adaptation of spin-free space have been developed.
    Additional Material: 4 Tab.
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  • 133
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    International Journal of Quantum Chemistry 35 (1989), S. 751-760 
    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: Formulas for the energies and widths of shape resonances, i.e., quasi-stationary levels for a quantal particle moving in a spherically symmetric potential, valid also close to the top of the potential barrier, have been published by Drukarev, Fröman, and Fröman. On the basis of these formulas, in the present paper the potential is explicitly expressed in terms of experimental data on the energies and widths of the quasi-stationary states. The treatment is related to previous treatments by Wheeler and by Cole and Good, Jr., which are in turn related to the Rydberg-Klein-Rees method.
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  • 134
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    International Journal of Quantum Chemistry 35 (1989), S. 711-715 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A personal and partially anecdotal account is given of the role of the Debye-Waller factor in protein crystallography and protein dynamics.
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  • 135
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    International Journal of Quantum Chemistry 35 (1989), S. 745-749 
    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 quantum system is repeatedly prepared in the same way and then observed in measurement processes. The following problem is stated and solved: Given the results of a series of observations, what is the best guess for a density matrix describing the ensemble of prepared systems? The corresponding classical problem and its solution are obtained as a special case.
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  • 136
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    International Journal of Quantum Chemistry 35 (1989), S. 801-811 
    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: Some aspects of R matrix theory that derive from a finite element method implementation of a hyperspherical coordinate formulation of the quantum mechanical three-body problem are analyzed with a view of designing suitable algorithms. Propagation of the R matrix from a hyperspherical surface to asymptotically appropriate wave fronts is given special attention.
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  • 137
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    International Journal of Quantum Chemistry 35 (1989), S. 851-867 
    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
    Additional Material: 6 Ill.
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  • 138
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    International Journal of Quantum Chemistry 36 (1989) 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 139
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    International Journal of Quantum Chemistry 35 (1989), S. 887-893 
    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: New solutions for reaction-diffusion equations, called singletons and polytons, are found to be of fundamental significance. They exhibit properties of self-formation. In the presence of nonlinear saturation effects their evolutions in time have pronounced maxima. Information about details of an initial spatial distribution is found to be carried along in time with the dynamic process of forming a growing singleton and to be restored at a later stage.
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  • 140
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Compton spectra excited by 241Am radiation have been measured on thin single-crystal slices with the scattering vector oriented parallel and perpendicular to the pair of hydrogen bonds in the (HCO3)22- dimers as well as to the plane of the dimers. the reciprocal form factors extracted from the spectra are strongly anisotropic with two extra zero passages in the direction of the hydrogen bonds. the results are in very satisfactory agreement with theoretical data that are calculated for the dimer with and without additional point charges simulating the neighboring ions in the crystal. The calculations have been done with Gaussian basis sets of double-zeta quality within the Hartree-Fock approximation. The theoretical reciprocal form factors of the monomer HCO3- and the dimer show only small differences in the directions perpendicular to the hydrogen bonds, whereas the differences in the hydrogen bond direction are remarkable and account for the experimentally observed features. In comparison to this effect the influence of the neighboring ions by their charges is much smaller, which is even true when taking into account the influence of the neighboring dimers in the crystalline stack in more detail by symmetrical orthogonalization of the combined wave functions. The same orthogonalization procedure applied to a pair of monomers in the spatial arrangement of the dimer yields a reciprocal form factor that in the experimentally reliable range above 1.8 Å accounts for most of the dimerization effect in the direction of the hydrogen bonds. Thus also for this prototype of paired hydrogen bonds (cf., carboxylic acids, DNA, and RNA), it confirms our earlier experimental finding on liquid water now unambiguously, namely that, in the same way as the cohesion in ionic crystals, hydrogen bond formation in bulk matter is distinctly dominated by electrostatic attraction, which is compensated by repulsion owing to the Pauli principle.
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  • 141
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    International Journal of Quantum Chemistry 36 (1989), S. 105-118 
    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: The effect of molecular interaction on the O—H stretching force constant of methanol (MeOH) is reported for its associated species. The various electron donors (D) and acceptors (A) considered include organic molecules such as methanol, dimethylether, acetone, acetonitrile, dimethyl formamide, pyridine, and ions such as F-, Cl-, Li+, and H+. The variation in the O—H stretching force constant of MeO—H…D species on interaction with the electron acceptor such as in the species is explained on the basis of the cooperativity effect. (CE). The effect is discussed in terms of the relationship CE = (ΔF/F) × 100, where ΔF is the reduction is force constant of the hydrogen-bonded O—H stretching mode of the associated methanol species MeOH…D when the lone pair electrons on oxygen of the methanol molecule are involved in hydrogen bonding with A, and F is the hydrogen-bonded O—H stretching force constant of the species when the lone pair electrons are free. The cooperativity effect (CE) is found to increase with increasing electron acceptor and electron donor capacities of A and D. The calculated force constants are compared with the experimental results.
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  • 142
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    International Journal of Quantum Chemistry 36 (1989), S. 473-486 
    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: It is shown that doubly excited states play an important role in calculations of the optical activity of molecules with well-conjugated electron systems, such as the DNA bases. In some significant cases it is necessary to include a large number of excited states in the configuration interaction (CI) to obtain a reliable, converging result. A new version of the CNDO/OPTIC method, which includes doubly excited states in the CI, is proposed. As an application, the electric transition moments in different pyrimidines are considered. The calculated results agree with experimental data and results obtained from ab initio calculations and INDO calculations using doubly excited states in the CI.
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  • 143
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    International Journal of Quantum Chemistry 36 (1989), S. 525-531 
    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: The derivative of the electron-electron potential energy Uee with respect to internuclear separation R is studied for light homonuclear diatomic molecules at equilibrium. It is readily related to nuclear-nuclear potential energy Unn, the force constant K, and the electron-nuclear potential energy Uen. An approximate expression, based on the simplest form of density functional theory, is then used to eliminate dUen/dR|Re. The result thus obtained for dUee/dR|Re transcends an earlier proposal of Kryachko by including a term 2/3ReK, with K the force constant. Numerical tests at SCF-RHF level are presented for nine homonuclear diatomic molecules.
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  • 144
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    International Journal of Quantum Chemistry 36 (1989), S. 543-543 
    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
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  • 145
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    International Journal of Quantum Chemistry 36 (1989), S. 563-573 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spectroscopically parametrized CNDO/S3 model is used to provide a quantitative description of the valence electron photoemission and ultraviolet absorption spectra of a series of substituted phenols and anisoles. The CNDO/S3 density of valence states was used to determine the molecular conformation of these molecules via analysis of gas-phase photoemission spectra. These conformations, in turn, were used to quantitatively determine the ultraviolet absorption spectra.
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  • 146
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    International Journal of Quantum Chemistry 36 (1989), S. 599-632 
    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 spin-free symmetry-adapted valence bond (VB) state, named bonded tableau (BT), is deduced from the classical bonded function and labeled by an at most two-column Weyl tableau. The complete set, which is composed of the BT basis or canonical bonded tableau (CBT), can be constructed from an overcomplete set of BT states. CI CBT and VB CBT are two kinds of complete sets that are constructed in this paper. They can be used, respectively, in the CI and VB theory. It is shown that there is a one-to-one correspondence between the labeling scheme for CI CBT and the Gelfand-Tsetlin (GT) basis. This relationship enables an efficient generation and compact representation of the BT basis if one desires to use the known global representation scheme for the GT basis. Effective algorithms for the matrix element evaluation of unitary group generators and products of generators between BT states are presented. In the formulation, the action of a generator on a BT state yields another BT state times a coefficient, so that the matrix elements of an arbitrary multiple product of generators are reduced to a calculation of the overlaps between BT states. The evaluation of the overlaps leads to a simple factorization into cycle contributions, whose values are given explicitly and only depend on the length parameters of the cycles. It is hoped that the presented formalism can facilitate the procedures for handling of the many-electron correlation problem.
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  • 147
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    International Journal of Quantum Chemistry 36 (1989), S. 647-657 
    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 well-known model of two coupled Morse oscillators is studied within the context of box quantization. Two variants are considered: analysis of stabilization graphs or addition of an optical potential. These methods are shown to give efficient alternatives for the determination of unimolecular dissociation rates.
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  • 148
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 149
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    International Journal of Quantum Chemistry 36 (1989), S. 533-533 
    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
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  • 150
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    International Journal of Quantum Chemistry 36 (1989), S. 541-541 
    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
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  • 151
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    International Journal of Quantum Chemistry 35 (1989), S. 433-439 
    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: We show that even when the nuclear motion is quantum mechanically described, the energy of a molecular state can be exactly expressed as a sum of terms, each one related to a nuclei of the molecule. This is a generalization of a similar result obtained by Politzer and Parr for the case in which the nuclei are in fixed positions. In fact, the nuclear motion is exactly taken into account through a modified screening function derivative evaluated on each nucleus of the molecule. We discuss how the screening function derivatives corresponding to the fixed nuclei case relate to those which take into account the nuclear motion. A simple relation between these two arises in the so-called crude Börn-Oppenheimer approximation.
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  • 152
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    International Journal of Quantum Chemistry 35 (1989), S. 461-470 
    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 combinatorial derivation of the product of the class of three cycles, [(1)N-3(3)]N with an arbitrary class operator of the symmetric group SN is presented. The form of this result suggests a conjecture concerning the expression of the general class operator product in terms of a relatively small number of reduced class coefficients. The conjecture is applied to the determination of the products of [(1)N-4(4)]N, [(1)N-4(2)2]N, and [(1)N-5(5)]N with arbitrary class operators. General expressions for the reduced class coefficients of the simplest type are obtained.
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  • 153
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    International Journal of Quantum Chemistry 35 (1989), S. 513-518 
    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: The local energy is examined as an indicator of the accuracy of approximate wave functions for the ground state of helium. It is observed that at a given point (1) an inaccurate local energy may or may not correspond to an inaccurate value of the wave function or probability density, but (2) a value of the local energy within 0.1 a.u. of the ground-state energy corresponds to a value of the approximate wave function or probability density within about 10% of that for the ground-state wave function.
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  • 154
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    International Journal of Quantum Chemistry 35 (1989), S. 567-575 
    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 configuration-averaged Fock (CAHF) operator is developed within the restricted open-shell formulation (ROHF) for the case of any number of open-shell orbitals containing any number of electrons. The resulting orbitals and energies should be useful for those cases where there is a great degeneracy of states, either preventing self-consistent field convergence, or negating the value of a pure state description itself. This procedure is compared with the hyper-Hartree-Fock method of Slater and the grand canonical Hartree-Fock ansatz of Abdulnar, Linderberg, Öhrn, and Thulstrup.
    Additional Material: 2 Tab.
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  • 155
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    International Journal of Quantum Chemistry 35 (1989), S. 585-592 
    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 new unitary operator U, which can transform the Fock space of a three-dimensional isotropic harmonic oscillator into the space in which the Hamiltion of three coupled oscillators is diagonized, is found. The coordinate representation of U is presented and is used to directly derive the wave function of the energy eigenstate of the coupled oscillators.
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  • 156
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    International Journal of Quantum Chemistry 35 (1989), S. 649-663 
    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 explicit relation is derived between the one-body potential energy and the electron density for the ground state of the Be atom in a nonrelativistic framework. This same relation applies to any four-electron atomic ion (or to Be itself) in a state where the electrons occupy two doubly filled orbitals. The relation is interpreted as an exact Hartree-like model of the Hohenberg-Kohn theorem within the general context of N electrons and a potential that is not necessarily spherically symmetrical.
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  • 157
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    International Journal of Quantum Chemistry 36 (1989), S. 391-415 
    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 short review of the recent development of the stochastic approach to chemical reactions in condensed media is made. The relations of this approach to a general formulation of chemical kinetics are discussed on the basis of a many-frequency oscillator model. It is shown that the classical transition-state theory is not a particular case of the stochastic theory neither in the case of small viscosity nor in the case of large viscosity. The recent quantum generalizations of the stochastic theory are identical to earlier results of a quantum transition-state theory that correspond to the case of large viscosity. Such generalizations based on previous results of a collision theory are made for the case of small viscosity. It is shown that these quantum generalizations of the stochastic theory are possible only in the temperature range of moderate tunneling defined in terms of a characteristic temperature.
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  • 158
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    International Journal of Quantum Chemistry 36 (1989), S. 689-704 
    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: Correlation forms for electrons of the same spin small molecules are analyzed by taking the LiH molecule as an example. The analyses are carried out on the basis of the reduced density matrix theory and for both the ground state and the first excited state. It turns out that although there is a certain similarity, the correlated motions of parallel-spin electrons in this four-electron molecule are more complicated than those found for the two-electron molecule. The correlation forms are not always constant. They vary essentially from one state to another, but are insensitive to fairly large changes of the internuclear distance for a given state.
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  • 159
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    International Journal of Quantum Chemistry 36 (1989), S. 727-739 
    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: Electronic structure and geometry of XY diatomics (X, Y = H, Na, K, Rb, Cs, Cu, Ag, and Au) have been studied by nonempirical versions of ZDO methods which account for major relativistic effects. Influence of the basis set size is investigated for these systems exhibiting the bonding controlled by the [(n - 1)d10]ns1[np0] ⃛ [(n - 1)d10]ns1[np0] interactions; [] are optical.
    Additional Material: 8 Tab.
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  • 160
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    International Journal of Quantum Chemistry 36 (1989), S. 749-764 
    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: We have separated the electrostatic potential of a molecule into two parts: an atomic-like part, which is expanded in spherical harmonics around each nucleus, plus an overlap part, expanded in ellipsoidal harmonics around each pair of nuclei. Neglect of the penetration effect in these expansions yields a superposition of point and line multipoles. We have studied the penetration effect for the case of the hydrogen molecules and suggest an approximation for the elliptical penetration effect as a screening factor in the electrostatic potential.
    Additional Material: 6 Ill.
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  • 161
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Penicillium funiculosum NRRL 13033 produced β-glucosidase and β-xylosidase activities when grown on wheat straw. The addition of some inducers (individually or in combination) to the fermentation medium were tested for the production of both enzymes. The relation of mycelial bound enzyme to cell free enzyme was studied during incubation period of fermentation. The optimum activity of β-glucosidase and β-xylosidase were found to be in the pH 4.5 using phosphate-citrate buffer at 50°C for 60 min and at 55°C for 40 min respectively. β-Glucosidase lost about 40% of its original activity by heating to 65°C for 60 min, while, β-xylosidase activity was found to be nearly stable with the same treatment. Both enzyme activities were greatly inhibited when 1.0% (w/v) of xylose and glucose were added to the assay mixture.
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  • 162
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    Acta Biotechnologica 9 (1989), S. 362-362 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 163
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    Acta Biotechnologica 9 (1989), S. 361-361 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 164
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: We report here the construction of a promoter-probe vector, pRS2, which can be utilized in either Acetobacter methanolicus MB 58 or Escherichia coli due to the presence of broad-host-range replicon RSF 1010. The vector provides several unique restriction sites for promoter cloning as well as resistance markers for the selection of transformants. The promoter-probe vector was constructed by inserting an EcoRI-SalI-polylinker fragment of pUC 19 into EcoRI/SalI digested pMK 16. The resulting plasmid, pRS1, was cloned into the unique EcoRI site of the broad-host-range plasmid RSF 1010.The vector was used to clone promoter-containing sequences derived from the A. methanolicus MB 58 chromosome as well as the E. coli lac-promoter.
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  • 165
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    Acta Biotechnologica 9 (1989), S. 233-238 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A technology for the fractionation of the small-value fish species Black Sea minnow (Spratus spratus phalericus) has been proposed. Four valuable fractions with a possibility for utilisation as food and health products have been proposed: the protein isolate, the aminoacid concentrate, the lipid fraction and the fish-bone fraction.
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  • 166
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    Acta Biotechnologica 9 (1989), S. 247-253 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The sorption capacity of silver on different biological materials has been investigated depending on physico-chemical pretreatments. The maximum silver loading values measured were compared with the values obtained with nontreated biomasses.The results show an increase of the loading capacity up to a factor of 10 in case of the alkalitreated biomasses. When the biomasses are extracted before being used as adsorbent with a solvent mixture of chloroform/methanol in a ratio of 2:1 the efficiency of the silver adsorbing power can be increased.Beyond that, the ability to adsorb silver can also be influenced when microorganisms are used as biocatalysts in a product synthesis before they are used as adsorbents. A strain of Acetobacter methanolicus possesses 1.8 times higher affinity to silver when it is employed in a process of gluconic acid production before adsorption. Physico-chemical pretreatments influence not only the loading capacity of the biological material, but also the contacting time required for the establishment of the adsorption equilibrium can be considerable reduced.
    Additional Material: 4 Ill.
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  • 167
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    Acta Biotechnologica 9 (1989), S. 268-268 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 168
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    Acta Biotechnologica 9 (1989), S. 383-387 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: UV/VIS diffuse reflectance spectroscopy and fluorescence spectroscopy have been used to investigate the cytochrome and pyridine nucleotide spectra during aerobic biomass growth of Saccharomyces cerevisiae followed by an anaerobic ethanol formation process. The cytochrome and NAD(P)H spectra are closely related to fermentation parameters such as biomass growth rate and ethanol concentration.
    Additional Material: 4 Ill.
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  • 169
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 170
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The selective and complementary interaction between the ligand bound to support surface and isolated substance is the key of the affinity chromatography. This is the reason of the research in the field of certain sorbents. They are obtained by chemical reaction of matrix with proper ligands. It is carried out mainly by using bifunctional substances which make the reaction with the ligand in question possible. This paper deals with the preparation of controlled porosity glass with reactive epoxy groups. In order to obtain such support and avoid application of a proper epoxy silane compound, the double-step reaction using simple agents was employed. The sorbent syntheses were optimized. The prepared sorbents were applied for coupling some carbohydrates and amino acids.
    Additional Material: 3 Ill.
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  • 171
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    Acta Biotechnologica 9 (1989), S. 294-294 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 172
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    Acta Biotechnologica 9 (1989), S. 295-298 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The aim of this work is to study the IR spectra of the different lignins precipitated from the produced liquor of different pulping conditions of bagasse and cotton stalks, also to study their antimicrobial activities towards some bacteria and fungi.
    Additional Material: 1 Tab.
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  • 173
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    Acta Biotechnologica 9 (1989), S. 291-293 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mutant of Corynebacterium glutamicum dependent on homoserine and resistant both to S-(2-aminoethyl)-L-cysteine and lysine hydroxamate, cultivated under submerged conditions for 4 days in a medium containing sucrose, corn-steep and pea nut meał hydrolyzate, accumulated 33.5 g/l lysine.
    Additional Material: 2 Tab.
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  • 174
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    Acta Biotechnologica 9 (1989), S. 324-324 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 175
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    Acta Biotechnologica 9 (1989), S. 346-346 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 176
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    Acta Biotechnologica 9 (1989), S. 325-332 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the present work, a mathematical model was developed regarding the immobilized living yeast cell reactor for sugar bioconversion to ethanol. The model, composed of a system of ordinary differential equations (ODEs) enables the computation of the paramters involved in the steady state reactor behaviour. Comparing the values computed through the integration of this mathematical model with the experimental data, it has been shown its capacity to describe sufficiently accurate the steady state behaviour of the continuous fixed film bioconversion reactor.
    Additional Material: 7 Ill.
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  • 177
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 178
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 179
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 180
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The increased interest in large scale production of biologically active molecules, as for example monoclonal antibodys, hormones, proteins and enzymes, has stimulated a rapid development of different methods to cultivate eukaryotic cells. Further progress in this field of modern biotechnology is expected not only from the selection of more productive cell lines and more efficient cultivation techniques, but also from the improvement in new bioreactor design and operation, which guarantees increased productivity per unit volume and reduces the downstream processing. Most important factors for a new reactor design in future will be the energy- and mass transfer, shear stress and scaleability. The provision of an adequate oxygen supply to large scale reactors is the most critical barrier to scale up. If oxygen is limited in a small degree, the result is inhibition of cell density and cellular efficiency in the production of the desired biomolecules. In addition, when methodologies are used which allow high cell densities and high metabolic active cells, the oxygen transfer becomes more important and, at the same time, more difficult. Since direct sparging of air into the cell-containing medium causes problems such as shear forces and foaming, new, efficient methods in bubble free aeration must be utilized. A new aeration system is presented, which is suitable to bubble-free aeration as well to separation of microcarrier-anchered cells from the harvested medium when running in a continuous perfusion mode. The efficiency of the CHEMCELL System regarding aeration and cell retention is demonstrated by the growth kinetics of BHK 21-cells in batch and perfusion mode.
    Additional Material: 6 Ill.
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  • 181
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The MODELBASE BIOTECHNOLOGY has been developed for gathering and processing data obtained from biochemical experiments. It covers the analysis of growth kinetics and production kinetics as well and may be used for calibration curve determination too. The implementation of models defined by the user is supported. Both, differential equations and their integrated forms are accepted. In addition to parameter estimation a statistical analysis can be carried on request. Two and three dimensional graphical representation facilitates the interpretation of results.Fields of application are biochemistry, biotechnology, microbiology, engineering, pharmacy, equipment design, education.
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  • 182
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    Acta Biotechnologica 9 (1989), S. 3-8 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Although the regulation of microbial secondary metabolism belongs to the important objects of actual investigations the results and knowledges are used rather poorly in industrial fermentations. This situation arises from the discrepancy between the economically driven development of the know how as soon as possible contrary to the more slow progress of profound examination of the complicated network of secondary metabolism. Nevertheless some well known principles of metabolic regulation, e.g. catabolite repression or resistance against products or metabolites are considered in fermentation processes by means of suitable substrate application as well as improvement of high yield strains. Both aspects are discussed with respect to examples of fermentations of β-lactams, polyketides and glycopeptides.
    Additional Material: 4 Tab.
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  • 183
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The loss of fermentative activity of yeast cells, observed in continuous fermentation experiments at increasing biomass concentration is explained by the assumption that the ethanol-tolerance behaviour of the microorganisms changes if a growth-stabilizing factor limitation is present. A mathematical specification of the relationships existing in this context is given and an improved steady-state productivity model of ethanol production is derived.
    Additional Material: 3 Ill.
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  • 184
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 185
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A controlled brew of pito was produced and compared with a native brew. The former contained a higher alcohol content than the latter brew and was brighter in colour (13 as against 18.5 EBC units) thus making it more attractive. Of various heat and chemical preservative treatments used to prolong the shelf life of both products, pasteurization at 75°C for 30 min. and treatment with sorbic acid at a concentration of 5% were best able to arrest microbial proliferation in the bottled products during a 4 week storage period.
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  • 186
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    Acta Biotechnologica 9 (1989), S. 143-148 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Nine Candida species isolated from fleshy fruits have been examined for their organic growth factor requirements. Complete or partial deficiencies for thiamine, biotin, pyridoxine, inositol, pantothenic acid, ascorbic acid and xanthine have been reported in C. catenuclta, C. curiosa, C. curvata, C. humicola, C. rhagii, C. steatolytica and C. tropicalis. Only two species, namely, C. fragicola and C. ishiwadea were prototrophic for the growth factors. Concentrations of essential growth factors higher than the optimum have been found inhibitory for the growth of yeasts.
    Additional Material: 1 Ill.
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  • 187
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    Acta Biotechnologica 9 (1989), S. 177-177 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 188
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 189
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    Acta Biotechnologica 9 (1989) 
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 190
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 191
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Proteins are separated by means of size-exclusion (SEC), hydrophobic-interaction (HIC) and ion-exchange chromatography (IEC). Analytical and semipreparative HPLC glass columns are the basis of the chromatographic analyses.Using a short (100 × 3.8 mm i.d.) column packed with Si 200 Polyol standard of different molecular weights (ovalbumin, MW = 43 000; chymotrypsinogen A, MW = 25 000; ribonuclease, MW = 13 700 and contrycal, MW = 6512) could be distinguished.Basic proteins (e.g., chymotrypsinogen A, cytochrome C) are separated on aluminium oxide (Li-Chrosorb Alox T) by cation-exchange chromatography. Correlations between the retention times of proteins and their isoelectric points or the buffer concentration of the mobile phase are investigated.Furthermore, two examples of liquid chromatographic purification procedures for enzymes of biotechnological interest are demonstrated. One enzyme extract (thermostable protease) is separated by hydrophobic-interaction chromatography, another one (β-galactosidase from a thermophilic microorganism) is purified on a weakly basic anion-exchange resin (pore size: 130 nm) based on a styrene-divinylbenzene copolymer.
    Additional Material: 8 Ill.
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  • 192
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    Acta Biotechnologica 9 (1989), S. 142-142 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 193
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    Acta Biotechnologica 9 (1989), S. 131-136 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The methanol-utilizing yeast Hansenula polymorpha MH 26 is thermotolerant and grows at 40°C and pH 3.5 with a maximum specific growth rate of 0.23 h-1 on methanol.In continuous cultivation the maximum cell yield can be improved of 0.35 (methanol) to 0.44 g dry cells/g methanol (mixtures of methanol and stillage) through additional utilization of the essential growth and nutritive substances of stillage.The utilization of methanol and sucrose (molasses) at various mixtures is simultaneous possible. Investigations of these mixtures with 14C-marked methanol show an increasing incorporation of methanol of about 20-30% against methanol alone. This effect is caused by the increasing metabolization of sucrose to carbondioxide and additional energy delivery for better assimilation of methanol.
    Additional Material: 3 Ill.
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  • 194
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    Acta Biotechnologica 9 (1989), S. 156-156 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 195
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    Acta Biotechnologica 9 (1989), S. 157-172 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: This review deals with known natural enzyme activities of streptomycetes and their applications. This knowledge may help potential users to exploit these organisms for individual purposes. The data given in tables are based on scientific publications and the IUPAC recommendations regarding nomenclature are followed. Included are only enzymes already utilized, with those of the primary metabolism being neglected.
    Additional Material: 6 Tab.
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  • 196
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    Acta Biotechnologica 9 (1989), S. 173-177 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: In an effort to use whey for lysine production, we isolated from a β-galactosidase-hyperproducing strain of E. coli K 12 multiple mutants - auxotrophic, regulatory and penicillin-resistant. These mutants exhibited for the most part a high reversion rate but some of them produced about 2 mg/ml lysine in an enriched fermentation medium.
    Additional Material: 2 Ill.
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  • 197
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    Acta Biotechnologica 9 (1989), S. 149-156 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies on the pelletization of fungus Pleurotus ostreatus have established the pellets to differ as to the size, density and chemical composition. Changes in the pellets, taking place during culture growth, are helpful in studying the mode of their development. We have studied various conditions of cultivation, and established the factors enhancing culture growth. Prehomogenization of seeds, velocity of stirrer revolution, partial pressure of dissolved oxygen and that of other factors was established to affect the structure of pellets and parameters of culture growth.
    Additional Material: 9 Ill.
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  • 198
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    Acta Biotechnologica 9 (1989), S. 388-388 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 199
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    Acta Biotechnologica 9 (1989), S. 392-392 
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 200
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