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  • 1985-1989  (1,125)
  • 1890-1899
  • 1800-1809
  • Life Sciences (general)  (596)
  • Biochemistry  (529)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Pharmacy world & science 11 (1989), S. 146-150 
    ISSN: 1573-739X
    Keywords: Agonists ; Antagonists ; Biochemistry ; Central nervous system ; Ligands ; Pharmacology ; Receptors, histamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The role of histamine in brain function is discussed. A brief review is presented on the three types of histamine receptors with regard to their biochemistry and functions, as well as on specific ligands, both agonists and antagonists. It is concluded that several aspects of the pharmacology of histamine in the central nervous system are still a matter of empirism and speculations. The recent publications on the brain-penetrating H2 antagonist zolantidine and the selective H3 agonists and antagonists are expected to contribute to the knowledge of the histaminergic pathways in the brain. Therapeutical areas within the central nervous system are related to behaviour (including wake-sleep), neuroendocrinal processes, the control of muscle activity and cerebral circulation.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Pharmacy world & science 11 (1989), S. 3-8 
    ISSN: 1573-739X
    Keywords: Biochemistry ; Clofazimine ; Dapsone ; Ethionamide ; Isoniazide ; Mechanism of action ; Mycobacterium leprae ; Prothionamide ; Quinolones ; Ribonucleotide reductase inhibitors ; Rifampicin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract From a pharmacochemical point of view the existing anti-leprotics as well as possible innovations in the chemotherapy of leprosy are discussed. Of the main anti-leprotics, which are used nowadays — dapsone, rifampicin, clofazimine, isoniazide, ethionamide and prothionamide — the mechanism of action, the main problems in their application and possibilities to develop improved variants are reviewed. Based on the chemistry ofMycobacterium leprae, the target systems for new anti-leprotics are identified. These systems include the cell wall, the catabolism of reactive oxygen species, the metabolisms of carbon sources, the amino acid metabolism and the uptake of iron. Two possible new lead structures from other fields, 4-quinolones and mycobacterial ribonucleotide reductase inhibitors are presented.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 514-519 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The charge on oxygen for a series of compounds was obtained using Mulliken population, natural population analysis (NPA), integrated projected electron population (IPP) analysis, and Bader's topological density analysis, “integrated Bader populations” (IBP). The orbital-based methods (Mulliken and NPA) predict oxygen charges of about -0.6 whereas the spatial-based methods (IPP and IBP) predict charges of about - 1.2 to - 1.3. The differences are ascribed primarily to the nuclear-centered basis sets used in the orbital methods that minimize local atomic polarization effects. Accordingly, such population analyses should be used for electronic structure considerations only with due circumspection. The IPP method as an approximation to IBP shows gross similarities; small but significant differences vary in a nonsystematic manner and IPP values must also be used with care.
    Additional Material: 2 Tab.
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  • 4
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: An SCF calculation has been performed on C63H113N11O12, a derivative of the immuno-suppressive drug cyclosporin, using a 3-21G basis set and a Direct SCF method. A distributed multipole analysis has been performed on the resulting charge density to give a set of multipoles at each atomic site, which are used to calculate the electrostatic potential around the molecule. The potential maxima and minima on the accessible surface of the molecule are compared with those predicted using the corresponding Mulliken charges, and also using a potential-derived point-charge model based on the force-field of Kollman et al. The Mulliken charges give a misleading picture of the electrostatic potential around this peptide. The potential-derived charges give results which are in far better agreement with the ab initio distributed multipole model, despite being derived from calculations on smaller molecules with different basis sets and geometries. The limitations of point-charge models for describing the electrostatic interactions of polypeptides are discussed.
    Additional Material: 2 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 616-627 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: We present a simple computational method for the evaluation of solute-solvent dispersion energy contributions in dilute isotropic solutions, supplementing the method with an analysis of its sensitivity with respect to several parameters (or features of the solvation model) which are left free in the general formulation. The method is a natural complement of the electrostatic solvation procedure described in preceding articles.
    Additional Material: 1 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 648-659 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Calculations of chemical shifts have been carried out using “locally dense” basis sets for the resonant atom of interest, and smaller, attenuated sets on other atoms in the molecule. For carbon, calculations involving a 6-311G(d) triply split valence set with polarization on the resonant atom and 3-21G atomic bases on other heavy atoms result in good agreement with experiment, and are virtually identical to those found employing the larger basis on all atoms. For species such as nitrogen, oxygen, and fluorine where standard balanced basis sets do not agree well with experiment, use of attenuated sets fail as well. The use of locally dense basis sets permits calculations previously impractical, and the successful application to carbon suggests that the chemical shift is most dependent on the local basis set, and less so on whether or not a balanced or unbalanced calculation is being carried out.
    Additional Material: 5 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 635-647 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The molecular mechanics calculations reported earlier for nitrogen heterocycles have now been extended to include the title compounds, and related molecules. It is in general possible to calculate these structures with an accuracy that compares favorably with experiment.
    Additional Material: 2 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 748-748 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 798-816 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A procedure that finds the most probable conformational states of a protein chain is described. Single-residue conformations are represented in terms of four conformational states, α, ∊, α*, and ∊*. The conformation of the entire chain is represented by a sequence of single-residue conformational states; the distinct conformations in this representation are called “chain-states.” The first article in this series described a procedure that computes tripeptide conformational probabilities from the amino acid sequence using pattern recognition techniques. The procedure described in this article uses the tripeptide probabilities to estimate the probabilities of the chain-states. The chain-state probability estimator is a product of conditional and marginal probabilities (obtained from the tripeptide probabilities), with a penalty factor to eliminate conformations containing α-helices and ∊-strands of excessive length. The probability estimator considers short-range conformational information, medium-range sequence information and some simple long-range information (through the restrictions on helix and strand lengths). Energy minimization calculations can be carried out in the region of conformational space corresponding to a particular chain-state. By selecting the most probable chain-states, the search can be focused on the most probable, or “important,” regions of the conformational space. These energy calculations are described in the third article of the series. The complete procedure described by the three articles is called PRISM, for pattern recognition-based importance sampling minimization.
    Additional Material: 1 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 817-831 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A procedure that generates random conformations of a protein chain, and then applies energy minimization to find the structure of lowest energy, is described. Single-residue conformations are represented in terms of four conformational states, α, ∊, α*, and ∊*. Each state corresponds to a rectangular region in the φ, ψ map. The conformation of an entire chain is then represented by a sequence of single-residue conformational states. The distinct “chain-states” in this representation correspond to multidimensional rectangular regions in the conformational space of the whole protein. A set of highly-probable chain-states can be predicted from the amino acid sequence using the pattern recognition procedure developed in the first two articles of this series. The importance-sampling minimization procedure of the present article is then used to explore the regions of conformational space corresponding to each of these chain-states. The importance-sampling procedure generates a number of random conformations within a particular multidimensional rectangular region, sampling most densely from the most probable, or “important,” sections of the φ, ψ map. All values of φ and ψ are allowed, but the less-probable values are sampled less often. To achieve this, the random values of φ and Φ are generated from bivariate gaussian distributions that are determined from known X-ray structures. Separate gaussian distributions are used for proline residues in the α and ∊ states, for glycine residues in the α, ∊, α*, and ∊* states, and for ordinary residues involved in 29 different tripeptide conformations. Energy minimization is then applied to the randomly-generated structures to optimize interactions and to improve packing. The final energy values are used to select the best structures. The importance-sampling minimization procedure is tested on the avian pancreatic polypeptide, using chain-states predicted from the amino acid sequence. The conformation having the lowest energy is very similar to the X-ray conformation.
    Additional Material: 9 Ill.
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 856-860 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Formulas are derived for analytical first and second energy derivatives with respect to nuclear coordinates in molecular mechanics force fields employing lone-pair pseudoatoms. These derivatives may further be used for the calculation of normal modes and vibrational frequencies while properly accounting for the presence of pseudoatoms. The equations are applied using the MM2 force field to calculate the vibrational spectrum of methanol to illustrate the applicability of the method. The results are compared to both experiment and a numerical approximation in which small masses are assigned to the lone-pair pseudoatoms.
    Additional Material: 1 Tab.
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 863-868 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The steric energy difference (ΔEst) between tertiary carbenium ions (R+) and the corresponding alcohols has been calculated by MM2 for a series of tertiary nonbridgehead substrates and correlated with their rate of solvolytic reactivity. Satisfactory correlation is obtained, except for p-nitrobenzoates of highly congested substrates. The slope and intercept of the correlations remain almost unchanged if bridge-head substrates are included in the plot. However, the quality of the fit is better for bridgehead substrates alone.
    Additional Material: 2 Ill.
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  • 13
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 753-769 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The well-tempered Gaussian basis sets (14s 10p) for atoms from lithium to neon were contracted and used in restricted Hartree-Fock calculations on 13 systems: Li2(Σ), B2(Σ), C2(Σ), N2(Σ), O2(Σ), F2(Σ), Ne2(Σ), LiF(Σ), BeO(Σ), BF(Σ), CN-(Σ), CO(Σ), and NO+(Σ). Spectroscopic constants (Re, ωe, ωexe, Be, αe, and ke) and one-electron properties (dipole, quadrupole, and octupole moments at the center of mass and electric field, electric field gradient, potential, and electron density at the nuclei) were evaluated and compared with the Hartree-Fock results. The largest contracted basis set (7s6p3d) gives results very close to the Hartree-Fock values; the remaining differences are attributed to the absence of the f functions in the present basis sets. For Ne2, the interaction energy was calculated; the magnitude of the basis-set superposition error was found to be very small (less than 3 μEh at 2.8 a0 and less than 2 μEh at 5.0 a0).
    Additional Material: 29 Tab.
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 832-849 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The geometries, relative conformational energies, and dipole moments of mono and polychlorosilanes have been calculated using ab initio molecular orbital (MO) theory. Calculations at the HF/3-21G(*) level, with the exception of dipole moments, give reasonable agreement with experimental data. A new MM2 force field for chlorosilanes, which includes terms for bond length shortening and bond angle compression due to the attachment of electronegative Cl atoms, has been developed on the basis of experimental and ab initio results. The new force field is generally successful in predicting structural parameters, but is unable to reproduce the dipole moments of several model systems. While dipole moment predictions are not the authors' main interest, this failure defines a shortcoming in the MM2 method. The new parameters have been applied to problems in the prediction of stereochemistries of cyclic systems, and compared with experimental results where data are available.
    Additional Material: 5 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 850-855 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Molecular dynamics simulations out to 100 ps have been carried out at 300 K in vacuo on the repeating pentapeptide, (VPGVG), of the elastin fiber. The structure employed in the simulation is a β-spiral (helical structure) with 2.7 pentamers per turn and with a 9.45 Å rise per turn and 21.6 Å rise per turn in the relaxed and extended states, respectively. Large amplitude backbone torsion angle fluctuations are observed in the relaxed state, and significant damping is observed upon extension, particularly in the suspended segments of the β-spiral structure. Accordingly the entropy change an extension was computed and found to be a substantial -1.1 entropy units per residue. The various energy components are compared for relaxed and extended states and the relevance of the results to the molecular mechanism of entropic elasticity is discussed.
    Additional Material: 1 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 965-974 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A modified scheme of a previously developed concept of atomic valence numbers in molecules is presented. The relation to population analysis is demonstrated. The scheme is suitable for ab initio wave functions with extended basis sets. The procedure involved a combination of symmetric orthogonalization and contraction of the basis set. The method is used for a systematic investigation of a series of compounds with first-row atoms from Li to F. The predicted atomic charges and valence numbers are in line with results from infrared spectroscopy and multipole moment analysis.
    Additional Material: 7 Ill.
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 55-62 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The determination of minima and saddle points on the potential energy surfaces of the hydrogen bonded species O2-HF and O2-H2O is performed with unrestricted Hartree-Fock calculations. Geometries, electron density distributions, and relative energies for every stationary point are reported. Only one true minimum is found for O2-HF and for O2-H2O, and this approximately corresponds to a structure where the partially positive hydrogen atom is located along one of the superoxide ion electron lone-pair directions. Calculated ΔH, ΔS, and ΔG values for the reaction between O2- and H2O are in good agreement with experimental data.
    Additional Material: 2 Ill.
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  • 18
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 17-34 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The procedure for deorthogonalization (D) of atomic orbitals in the semiempirical CNDO approach is reviewed. For comparative studies, CNDO/2, CNDO/2D, and STO-3G calculations of molecular dipole moments and Mulliken populations are carried out on 35 prototype molecules containing H, C, N, O, and F atoms. The calculated values are assessed on the basis of how well they agree with experimental trends, chemical bonding theories, and ab initio molecular orbital (MO) values. Results of analyses indicate that the CNDO/2D values for dipole moments are in reasonable agreement with experimental values, and those for net atomic charges and electron populations bear greater resemblance to the ab initio (STO-3G and 6-31G**) values than the original CNDO/2 values. These findings, together with those of previous investigators, demonstrate unequivocally the advantages of incorporating deorthogonalization into routine CNDO/2 or INDO calculations as a means to obtain reasonable estimates of charge distributions.
    Additional Material: 4 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 63-76 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Matrix elements for the first and second derivatives of the internal coordinates with respect to Cartesian coordinates are reported for stretching, linear, nonlinear, and out-of-plane bending and torsional motion. Derivatives of the energy with respect to the Cartesian coordinates are calculated with the chain rule. Derivatives of the energy with respect to the internal coordinates are straightforward, but the calculation of the derivatives of the internal coordinates with respect to the Cartesian coordinates can be simplified by the following two steps outlined in this article. First, the number of terms in the analytical functions can be reduced or will vanish when the derivatives of the bond length, bond angle, and torsion angle are reported in a local coordinate system in which one bond lies on an axis and an adjacent bond lies in the plane of two axes or is projected onto perpendicular planes for linear and out-of-plane bending motion. Second, a simple rotation transforms these derivatives to the appropriate orientation in the space-fixed molecular coordinate system. Functions of the internal coordinates are invariant with respect to translation and rotation. The translational invariance and the symmetry of the second derivatives for a system with L atoms are used to select L-1- and L(L-1)/2-independent first and second derivatives, respectively, of which approximately half of the latter vanish in the local coordinate system. The rotational invariance permits the transformation of the simplified derivatives in the local coordinate system to any orientation in space. The approach outlined in this article simplifies the formulas by expressing them in a local coordinate system, identifies the most convenient independent elements to compute, from which the dependent ones are calculated, and defines a transformation to the space-fixed molecular coordinate system.
    Additional Material: 2 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 77-93 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Radial dielectric constant (permittivity) functions for ionic solute, polar solvent systems of the type obtainable from the Lorentz-Debye continuum field formulations are reexamined. Major interest is focused on the assumptions underlying these formulations and their expression in limiting field behavior. The analysis is extended to dipolar solutes and the importance of two types of corrections are evaluated. The first draws connections with the concept of the reaction field as employed by Onsager. This correction is shown to be significant as regards range of predicted saturation effects and for dipole moment self-consistency, for the same type molecule serving as solute and solvent. The second type correction involves the phenomenon of electrostriction whose effects appear much more limited both in range and on the intensity of the fields necessary for its observation. Application of the permittivity functions developed to compute modified Born model hydration energies for a variety of ions is illustrated. Excellent asymptotic approximations for all radial permittivity equations of interest are also presented which should enhance their future utility.
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  • 21
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 94-98 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Theoretical analysis of the electronic effect of aromatic substituents was done with the use of the AM1 computational procedure. The gas-phase acidity of substituted benzoic acids was linear with the difference in the heat of formation between corresponding benzoic acids and benzoate anions, the energy of the highest occupied molecular orbital, and the net charge on the acidic oxygen atoms of the corresponding benzoate anions. The Hammett σ constant was linearly correlated with the net charge on the atoms of the acid moiety of substituted benzoic acids. The AM1 computational procedure satisfactorily reproduced the electronic properties of a wide variety of substituents.
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  • 22
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 99-103 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: For a series of simple alkyldisilanes, 3-21G (*) full gradient geometry optimizations have been performed to yield both structural and conformational energy data which was suitable for calibrating the MM2 force field for disilanes. We have examined several model structures which yielded sufficient information about the rotational potential around the Si-Si bond to enable us to revise and augment those reported by Frierson. These parameters were questioned by us in the course of MM2 studies of 1,2-disilacyclobutanes. We report new Si-Si torsion parameters as well as pertinent structural data from 3-21G(*) geometry optimizations and relative conformational energies derived from Møller-Plesset (MP2/MP3) calculations at the 6-31(*)/3-21G(*) level. The new parameters were applied to the 1,2-dimethyl-1,2-disilacyclohexane system and those results are also reported.
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  • 23
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 104-111 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Three improvements on the direct self-consistent field method are proposed and tested which together increase CPU-efficiency by about 50%: (i) selective storage of costly integral batches; (ii) improved integral bond for prescreening; (iii) decomposition of the current density matrix into a linear combination of previous density matrices - for which the two-electron contributions to the Fock matrix are available - and a remainder ΔD, which is minimized; construction of the current Fock matrix only requires processing of the small ΔD which enhances prescreening.
    Additional Material: 3 Ill.
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  • 24
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 112-117 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Practical methods of generating reliable and economic basis sets for relativistic self-consistent fields (RSCF) calculations are developed. Large component basis sets are generated from constrained optimizations of exponents in the nonrelativistic atomic calculations for light atoms. For heavy atoms, large component basis sets for inner core orbitals are generated by fitting numerical atomic spinors of Dirac-Hartree-Fock calculations with appropriate number of Slater-type functions. Small component basis sets are obtained by using the kinetic balance condition and other computational criteria. With judicious selections of the basis sets, virtual orbitals in RSCF calculations become very similar to those in nonrelativistic calculations, implying that relativistic virtual orbitals can be used in electron correlation calculations in the same manner as the conventional nonrelativistic virtual orbitals. It is also evident that the Koopmans' theorem is also valid in RSCF results.
    Additional Material: 8 Tab.
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  • 25
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 137-137 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
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  • 26
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 136-136 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
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  • 27
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 138-138 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Type of Medium: Electronic Resource
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  • 28
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989) 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Type of Medium: Electronic Resource
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  • 29
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 118-135 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The theory of atoms in molecules defines an unambiguous partitioning of the three-dimensional electron density into atomic basins based on the zero-flux surfaces of the gradient of the electron density, ∇(r). Integrations of the electron density within such basins yield integrated Bader populations (IBP) that have a rigorous foundation in quantum mechanics. In the density integration technique based on the two-dimensional electron density projection function, P(x,z), integrated projection populations (IPP) are obtained by integration within regions demarked by steepest descent lines Dp of P(x,z). These density integration techniques are compared by an analysis of the electron density of diatomic molecules that is based on the properties of the zero-flux surface that partitions the electron density between the atoms. The conventional method for the partitioning of regions of P(x,z) approximates the virial partitioning. Differences between IPP and IBP can be quantitatively described by two terms. One term reflects the error intrinsic to projection populations as a result of the loss of all information about the electron distribution in the third dimension in the calculation of P(x,z). The second term accounts for the effects of the displacement of the demarcation lines Dp toward the less polarizable atom compared with the cross-section of the density with the plane of projection, Dd. The analysis suggests the definition of a projection population IPP2 that is based on the cross-section Dd instead of the demarcation lines Dp. Relations between the populations IPP, IPP2, and IBP are derived for diatomic molecules and numerical results are presented for a series of diatomic molecules. Several polyatomic anions are also discussed. The values of IPP are found to be good approximations of IBP in highly polar diatomic molecules. In cases where the bonding involves comparatively little intramolecular charge transfer IPP2 is the better and equally satisfactory projection population. In the intermediate semipolar bonding situations projection populations provide qualitatively correct descriptions of the charge distributions but the numerical agreement with the IBP values is less satisfactory.
    Additional Material: 8 Ill.
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  • 30
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 145-151 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Results of molecular orbital (MO) calculations by the complete neglect of differential overlap (CNDO/2) method on 50 small molecules are reported. The summation of calculated atomic polarizabilities are equated with molecular polarizabilities, and these are compared with experimentally determined values. It is found that there is very good agreement between calculated and experimental molecular polarizability. This provides a reliable method for the determination of molecular polarizabilities for compounds for which experimental values are not known. The relationship between log P and polarizability is discussed and analyzed in terms of contributions from electronic components to the partitioning energy.
    Additional Material: 4 Ill.
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  • 31
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 163-175 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The potential energy surfaces for the proton transfer processes in H+(H2O)n with n=2 ∼ 11 have been studied using the semiempirical AM1 method. Two model systems were adopted: branched and linear systems. The branched system showed a tendency to form a bulk cluster, while the linear system showed a tendency toward a constant barrier height with increasing number of water molecules in the model system. The potential energy surfaces were discussed using Marcus theory. In the case of H+ (H2O)n with n=10 and 11, the intrinsic barrier to the proton transfer was found to be around 1.0 kcal/mol.
    Additional Material: 10 Ill.
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  • 32
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 152-162 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: An alternative route toward developing basis sets for post-Hartree-Fock calculations, the hybrid bond polarization function method, is investigated. Two new basis sets, denoted 6-31G(d, p)+ B and 6-31 + G(d,p)+B, are defined for the first-row hydrides. The dissociation energies of the first-row hydride species in their respective ground states are computed using full fourth-order Møller-Plesset theory, and compared with results obtained with large polarized basis sets containing no bond functions. It is shown that results are competitive even with basis sets as large as 6-311++G(3df,3pd), while computation times are reduced by a factor of 4 to 20. On empirical grounds, the basis set superposition error should be neglected entirely.
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  • 33
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 176-185 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A new method of eliminating the finite-time-step error inherent in diffusion quantum Monte Carlo is presented, utilizing an improved version of the existing differential techniques. An implementation is described and results of several small but representative calculations are discussed. The pertinent computation requirements on these systems were reduced by up to a factor of five by the new algorithm. It is speculated that this method may be easily applied to other quantum Monte Carlo and discretized path integral Monte Carlo techniques having related finite step-size errors with a possibility of obtaining similar good results.
    Additional Material: 1 Ill.
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  • 34
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 209-220 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A new method for obtaining optimized parameters for semiempirical methods has been developed and applied to the modified neglect of diatomic overlap (MNDO) method. The method uses derivatives of calculated values for properties with respect to adjustable parameters to obtain the optimized values of parameters. The large increase in speed is a result of using a simple series expression for calculated values of properties rather than employing full semiempirical calculations. With this optimization procedure, the rate-determining step for parameterizing elements changes from the mechanics of parameterization to the assembling of experimental reference data.
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  • 35
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 203-208 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The stochastic search method was used to seek all of the conformations for 32 bicyclic hydrocarbons. Since the size of the random kick used is sufficient to invert the configurations of carbon atoms, the out, out, in, out, and in, in conformations were all found in a single stochastic run for each hydrocarbon. The lowest energy conformer obtained in each category is reported. A modification of the program to prevent inversion of configuration was developed. It was found, in some cases, that in, in and out, out isomers for some bicyclic hydrocarbons were interconverted by this modified program, presumably through the “homeomorphic isomerization” process described by Park and Simmons. A statistical formula for estimating the approximate chances of finding (or missing) any conformer as a function of the number of random kicks given is derived and presented.
    Additional Material: 3 Ill.
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  • 36
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 221-264 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: MNDO/AM1-type parameters for twelve elements have been optimized using a newly developed method for optimizing parameters for semiempirical methods. With the new method, MNDO-PM3, the average difference between the predicted heats of formation and experimental values for 657 compounds is 7.8 kcal/mol, and for 106 hypervalent compounds, 13.6 kcal/mol. For MNDO the equivalent differences are 13.9 and 75.8 kcal/mol, while those for AM1, in which MNDO parameters are used for aluminum, phosphorus, and sulfur, are 12.7 and 83.1 kcal/mol, respectively. Average errors for ionization potentials, bond angles, and dipole moments are intermediate between those for MNDO and AM1, while errors in bond lengths are slightly reduced.
    Additional Material: 4 Ill.
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  • 37
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    Journal of Computational Chemistry 10 (1989), S. 186-202 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: π-Electron delocalization in neutral and protonated “doubly-extended-guanidine,” (H2N)2C=N—CH=N - CH=NH, has been studied by ab initio methods at the self-consistent field (SCF) STO-3G and 3-21G levels for a large number of tautomeric, rotameric, pseudocyclic, and monocyclic (disubstituted triazine) forms. These π systems have been characterized in terms of a number of structural and energetic parameters: degree of single/bond character from bond lengths and π bond orders, electron distributions, and tautomer, rotamer, and protonation energies. The acyclic neutral forms exhibit largely alternant single-double bond patterns as predicted by classical bonding structures but with, however, significant deviations due to conjugation. The acyclic protonated forms exhibit bond patterns consistent with resonance delocalized structures extending over the whole molecule (“doubly-extended guanidinium”) or part of the molecule (“extended-guanidinium”) or guanidinium . All systems showed alternant charge distributions with electron-deficient carbons. The energy results have been analyzed in terms of possible contributions from steric interactions, lone-pair repulsions, purportive electrostatic interactions in pseudocyclic forms, overall π-system conformation (extended, kinked, or folded), and specific through-space π-overlap interactions in some pseudocyclic forms. It was found that these other interactions usually dominate the specifically π effects so that the general concept of preferential π delocalization in straight lines does not hold for the acyclic systems. Some interesting examples of pseudocyclic forms exhibiting strongly stabilizing intramolecular interactions attributed to π through-space coupling are identified. These systems with incipient-ring characteristics present intermediate bonding models between the acyclic and closed-ring π systems. The extent of stabilization of the guanidinium-type cations by resonance delocalization in cyclic systems depended on whether it reinforced or interfered with the overall ring delocalization.
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  • 38
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989) 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
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  • 39
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 265-283 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A study of systems containing the title moiety is described, with special reference to the anomeric effect. We have calculated ab initio, using Gaussian-80 with the 3-21G basis set, all basic conformations of methylene-diamine (H2N—CH2—NH2) and its N-methyl derivative with full geometry optimization of energy minima and barriers. The structural data thus obtained, were then employed to parameterize Allinger's MM2-80 force field in a procedure similar to that described for oxygen derivatives, including hydrogen-bonding effects and C—N bond shortening in tertiary amines. This modification, termed MM2-AE was then used to calculate larger molecules, including N,N′-di- and N,N,N′,N′-tetramethyl-methylenediamine, various 1,3-diazane systems, and 1,4,5,8-tetraazadecalin derivatives of established (x-ray) structures. The results are discussed in light of their verificative and predictive power and appear to validate MM2-AE as a useful computational procedure.
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  • 40
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    Journal of Computational Chemistry 10 (1989), S. 479-487 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Ab Initio charge distributions for amino acid dipeptides are derived utilizing two medium-sized basis sets. Peptide charges differ in two ways from those of existing force fields: the magnitude of the peptide dipole and the dependency on the residue type. The merging of charge distributions of side chain and backbone fragments within a semiclassical model including polarization is investigated. Polarization plays a small, but distinct role in improving the correspondence with ab initio data derived for the complete dipeptide. A description in terms of partly overlapping, interacting fragments correlates well with the ab initio data. The method can be used to derive the electrostatic properties of biological macromolecules by combining accurate descriptions of short range interactions (using good quality basis sets on not too small fragments) with good classical models of long range interactions (using multicenter multipole expansions and atomic polarizability tensors). Factors limiting the accuracy of the present representations are discussed.
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  • 41
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    Journal of Computational Chemistry 10 (1989), S. 488-494 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Monte Carlo simulations have been performed to study the conformations of the pentapeptide fragments of normal adult (Thr-Pro-Glu-Glu-Lys) and sickle-like anemia hemoglobin (Thr-Pro-Val-Glu-Lys). The results show that the energy optimized conformation of normal adult hemoglobin-fragment agrees with the X-ray experiment and the theoretically determined conformation of the sickle-like anemia hemoglobin-fragment is identical with the conformation of the normal adult hemoglobin-fragment.
    Additional Material: 2 Ill.
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  • 42
    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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  • 43
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    Berlin : Wiley-Blackwell
    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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  • 44
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    Berlin : Wiley-Blackwell
    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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  • 45
    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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  • 46
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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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  • 47
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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.
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  • 48
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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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  • 49
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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.
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  • 50
    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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  • 51
    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.
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  • 52
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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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  • 53
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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.
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  • 54
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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.
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  • 55
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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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  • 56
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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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  • 57
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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.
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  • 58
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 59
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 60
    ISSN: 0138-4988
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    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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  • 62
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    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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  • 63
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    Berlin : Wiley-Blackwell
    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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  • 64
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    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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  • 65
    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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  • 66
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    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.
    Additional Material: 2 Tab.
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  • 67
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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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  • 68
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    Berlin : Wiley-Blackwell
    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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  • 69
    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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  • 70
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 9 (1989) 
    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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  • 71
    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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  • 72
    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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  • 73
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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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  • 74
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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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  • 75
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    Berlin : Wiley-Blackwell
    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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  • 76
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    Berlin : Wiley-Blackwell
    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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  • 77
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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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  • 78
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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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  • 79
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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
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  • 80
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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
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  • 81
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 82
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    Acta Biotechnologica 9 (1989), S. 389-391 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: At late stages of development of surface cultures streptomycetes producing anthracycline antibiotics were shown to form secondary colonies on PRIDHAM & GOTTLIEB'S medium with xylose. Stable variants obtained from them possessed an increased biological activity (by a factor of 2-3 times) due to the accumulation of amounts of antibiotically active anthracyclines.
    Additional Material: 1 Tab.
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  • 83
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 9 (1989) 
    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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  • 84
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 9 (1989), S. 421-430 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The efficiency of carbon substrate utilization is evaluated as the thermodynamic efficiency (ηx) of microbial growth.Three methods based on mass-energy balance are used for the efficiency studies of complex substrates (straw, plant juices, lye) utilization by microfungi Trichoderma viride.1According to substrate and biomass balance ηx = 0.55, 0.37 and 0.36 for Trichoderma viride growth on alkali pretreated wheat straw during 23, 34 and 50 hours. Cellulose biodegradation increases with cultivation time. However, the efficiency of cellulose utilization for cell mass growth decreases at the same time.2In accordance with oxygen-balance calculations ηx = 0.75 and 0.71 for the same processes. The discrepancy in results from the above two methods probably can be explained by the following: ASubstrate and biomass balance gives underestimated results.BOxygen balance method includes the part of energy for extracellular product formation and therefore ηx can be overestimated.CThe efficiency of complex soluble substrate utilization (lye, green juice, deproteinized brown plant juice) tested by means of pulse method gives the values of ηx = 0.72 - 0.88. Similar high estimates of ηx in C-limited batch culture are observed for soluble carbohydrates (glucose, galactose, lactose, xylose) but not for acetate. The pulse method is advantageous for testing the “true” efficiency of carbon substrate utilization in a definite physiological environment.
    Additional Material: 3 Ill.
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  • 85
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 86
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 9 (1989), S. 485-489 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The degradation of fifteen sugars, sugar acids and related substrates were examined using cellfree extracts of Aspergillus ustus growing on D-glucose, D-mannose, D-galactose or D-gluconate as the only carbon source. D-gluconate was superior for the induction of the enzymes capable for the degradation of some of these substrates. The addition of 0.5% malt extract with D-gluconate to the growth medium or the presence of shaking conditions resulted to an increase in the degradation of those substrates, whileas the incorporation of 0.5% malt extract alone to the medium has no effect. Extracts of D-gluconate-grown mycelia of A. ustus degraded D-gluconate 〉 D-galactonate 〉 1 : 5 gluconolactone and 〉 L-arabonate nonphosphorolytically more effectively. Optimum pH and temperature for the degradation of D-gluconate were found to be 8.0 and 40°C, respectively. Thermal stability studies on the behaviour of D-gluconate dehydratase showed that this enzyme was stable at 50°C and 60°C for 30 and 5 minutes, respectively. Specific activity of this enzyme was increased three times when cell-free extracts were incubated at 60°C for 5 minutes. MgCl2 and CoSO4 were good activators, while CaCl2 p-mercurychlorobenzoate (PMCB), sodium arsenite, ZnSO4, CuSO4, iodoacetic acid, MnCl2 and FeSO4 were potent inhibitors for D-gluconate dehydratase activity. Km was calculated for D-gluconate and found to be 2.5 × 10-2 M.
    Additional Material: 2 Ill.
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  • 87
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 88
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A measuring device for the quasicontinuous determination of volatile substances in aqueous liquids, especially alcohols (methanol or ethanol) in fermentation media is presented. The working principle and the construction of this instrument are described. Measurements are possible in a concentration range between 0.1 and 150 g/l. The measuring device is suited for industrial processes as well as for laboratory use.
    Additional Material: 1 Ill.
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  • 89
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three different instruments for the determination of turbidity in liquid media are described. The SLP-2 was developed for the control of high biomass concentrations in fermenters and is fitted with a self-cleaning mechanism. The SLP-3 is used for control of very small turbidities, e.g. in brewery products or in drinking water. The SLP-4 is designed for continuous measurement of higher turbidities in (waste) water or in different products flowing through pipe-lines. It may be used alternatively as a submerged probe.
    Additional Material: 2 Ill.
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  • 90
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Study was made of the effect of medium humidity, source and dose of nitrogen, dose of phosphorus, dose of inoculum and aeration on protein biosynthesis by strain Aspergillus oryzae A. or. 11 in solid state fermentation. It was found that for a maximal protein yield the medium ought to contain about: 60% of water, 36% of starchy raw materials d. m. (e.g. 28.8% of coarse rye meal and 7.2% of beet pulp), 0.85% of nitrogen sources (1.6% of (NH4)2SO4 and 1.1% of urea), and 0.35% of phosphorus source (1.3% of KH2PO4). pH of medium should be near 6.5. The dose of inoculum should not be lower than 108 spores/100 g medium.The duration of culture ought to be 20-22 h at 30-35°C, with aeration at least 40 dm3 of air/h × 1000 g medium. Under these conditions the protein yield is about 6.0-6.3 g/100 g of starting medium d.m. at the cost of utilization of about 25 g total carbohydrates.
    Additional Material: 5 Ill.
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  • 91
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    Acta Biotechnologica 9 (1989), S. 55-62 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method for the analysis of distributed growth of E. coli in k-carrageenan gel is described. The method uses optical and electron microscopy to determine morphometric data of cell microcolonies in the gel, such as average microcolony volume, distance of microcolonies to gel surface and cell density in the microcolonies. Logarithmic equations describing the distribution of authentic values of volume occupied by cells in gels at different times of incubation were determined. With these equations it is possible to predict the quantitative distribution of cells in the gel and to define some parameters. These parameters can characterize the growth behaviour of the microbial strains in any particular culture condition and can be useful in the future search to improve the industrial applications of immobilized cells.
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  • 92
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    Acta Biotechnologica 9 (1989), S. 68-68 
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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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  • 93
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this work, new packings consisting of home made controlled porosity glass, new self-prepared aminoorganic silanes and vanillin as a ligand were used for affinity chromatography of some plant peroxidases (donor: H2O2 oxidoreductases; EC 1.11.1.7). The procedure allowed simple and relatively high purification of enzymes. The results were compared with those obtained with the material including commercially available γ-aminopropyltriethoxysilane.
    Additional Material: 3 Ill.
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  • 94
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 9 (1989) 
    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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  • 95
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 96
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    Acta Biotechnologica 9 (1989), S. 110-110 
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 97
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    Acta Biotechnologica 9 (1989), S. 111-121 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Measurements of liquid macromixing characteristics are reported for a half industrial scaled jet loop reactor operating with air-water mixtures. Based on a model of loop reactors with sections of different mixing behavior the single circulation dispersion coefficient can be split into its components caused by the riser and the downcomer. The dispersion coefficient of the riser is about 100 times greater than that of the downcomer. The addition of gas involves greater dispersions coefficients. The comparison of the mixing times of the JLR with those of stirred vessels leads to the conclusion that the JLR is equivalent or even superior to stirred vessels.
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  • 98
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    Acta Biotechnologica 9 (1989), S. 130-130 
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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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  • 99
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 100
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    Acta Biotechnologica 9 (1989), S. 191-195 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three cellulase components and one xylanase of Trichoderma sp. M-17 have been immobilzed on a soluble high molecular weight polymer (PVA), using carbodiimide. The immobilized enzymes retained about 80% of the cellulase, cellulose 1,4-β-cellobiosidase, β-glucosidase and 60% endo-1,4-β-xylanase activities. The bound enzymes catalyzed the hydrolysis of alkali-treated cornstalks with a higher efficiency than the free cellulase. The potential for reutilization of the immobilized enzymes was studied using membrane filters and the system was found to be active for three cycles.
    Additional Material: 1 Ill.
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