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  • 11
    Electronic Resource
    Electronic Resource
    Quantitative glomerular morphology of the normal and diabetic baboon kidney (1986)
    Springer
    Diabetologia 29 (1986), S. 734-740 
    Details
    ISSN: 1432-0428
    Keywords: Basement membrane ; mesangium ; diabetes ; baboons ; pancreatectomy ; quantitative glomerular morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This is a study of quantitative glomerular morphology in 14 normal and 6l ong-term diabetic female baboons between 3 and 25 years of age. In the normal female baboon, peripheral glomerular capillary basement membrane thickness increased until around 10 years of age, reached a plateau between 10 and 20 years of age, and possibly decreased at 25 years of age. Mean values for young (3 to 7 years of age) and older (10 to 25 years of age) controls were 266 nm and 329 nm respectively. Fractional volumes of mesangial matrix (8.9%) and mesangial cells (6.8%) were not affected by age. Glomerular basement membrane thickness and the volume of mesangial matrix increased progressively in female baboons with poorly controlled pancreatectomy-induced diabetes, while the volume of mesangial cells remained unchanged. After 106 to 145 months of diabetes, glomerular basement membrane thickness and the volume of mesangial matrix were 558 nm and 18.7% respectively. These values were significantly greater than those of the age-matched controls (p = 〈 0.05). By light and electron microscopy, the normal baboon glomerular morphology, morphometric measurements and changes with age were similar to those in man. The renal changes in diabetic baboons were also similar in morphology and rate of development to those of mild to moderate diffuse diabetic glomerulosclerosis in humans, indicating that the baboon is an ideal model for the long-term study of diabetic glomerulosclerosis. The presence of considerable interanimal variability in the degree of glomerulosclerosis attained after prolonged diabetes suggested that glomerulosclerosis progressed at different rates in these models. The reason for this was not apparent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00870284
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  • 12
    Electronic Resource
    Electronic Resource
    The electronic structure of the NF2 radical (1973)
    Springer
    Theoretical chemistry accounts 28 (1973), S. 339-353 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Ab intio-Rechnungen nach der uneingeschränkten Hartree-Fock-Methode (UHF-Methode) (mit und ohne einfache Auslöschung) wurden für das Radikal NF2 mit verschiedenen Basissätzen durchgeführt. Die vier Basissätze sind: ein minimaler Basissatz von Slaterfunktionen, zwei minimale Basissätze von Gaußfunktionen und ein größerer Satz von Gaußfunktionen von angenäherter Genauigkeit einer Doppelzeta-Basis. Der Vergleich der Basissätze bei der Berechnung von ladungsabhängigen Einelektron-Eigenschaften zeigt, daß der angenäherte Doppelzeta-Basissatz zur Berechnung geeigneter Werte notwendig ist. Eine einfache Auslöschung in den UHF-Wellenfunktionen, die mit den beiden Basissätzen mit genäherten Doppelzeta-2p-Funktionen berechnet wurden, führte auf eine genaue Darstellung der anisotropen Kopplungskonstanten am Stickstoff und an Fluor. Die Übereinstimmung der berechneten isotropen Kopplungskonstanten war bei allen Rechnungen weniger gut. Diese Ergebnisse für das NF2-Radikal zeigen, daß bei Verwendung einer geeigneten Basis mit Hilfe der UHF-Methode mit einfacher Auslöschung genaue Werte für die meisten von der Ladung oder vom Spin abhängigen Eigenschaften von Molekülen mit offenen Schalen gewonnen werden können.
    Notes: Abstract Ab initio unrestricted Hartree-Fock (UHF) calculations (with and without single annihilation) have been performed on the radical NF2 using four different basis sets; namely, a minimal basis Slater set, two minimal basis Gaussian sets and a Gaussian set of approximately double zeta accuracy. Several one-electron charge dependent properties have been calculated with each basis set and it is most apparent that near double zeta accuracy 2p functions are necessary to produce reliable values. Single annihilation of the UHF wavefunctions calculated with the two basis sets containing near double zeta 2p functions, was found to give an accurate representation of the anisotropic coupling constants at both the nitrogen and fluorine atoms. Less satisfactory agreement with the experimental isotropic coupling constants was found with all calculations. This investigation of the NF2 radical indicates that, providing a good quality basis set is used, the single annihilated UHF method can provide accurate values for most charge and spin dependent observable properties of open shell molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00529015
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  • 13
    Electronic Resource
    Electronic Resource
    Simplified ab-initio calculations for molecular systems (1970)
    Springer
    Theoretical chemistry accounts 18 (1970), S. 98-106 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine Methode zur Reduzierung eines großen Teiles der Rechnungen ohne merklichen Verlust an numerischer Genauigkeit in der exakten ab initio SCF-MO-Methode, die auf Slater-Orbitalen basiert, wird beschrieben. Das Verfahren beinhaltet die Transformation zu orthogonalen Orbitalen nach Löwdin und benutzt die NDDO-Näherung. Die erforderlichen Drei- und Vier-Zentrenintegrale werden mit Hilfe der abgebrochenen Ruedenberg-Entwicklung geschätzt. Alle Ein-Elektron-Integrale werden exakt berechnet. Keine empirischen Parameter werden benutzt. Numerische Untersuchungen für CO, OF2, O3 und ONF zeigen, daß die NDDO-Näherung sehr genau für Löwdin-Funktionen ist, und daß die Ruedenberg-Entwicklung numerisch zufriedenstellend für die SCF-MO-Berechnungen ist.
    Abstract: Résumé Description d'une méthode pour réduire une grande partie des calculs numériques d'une méthode SCF ab initio en orbitales de Slater, sans perdre pour autant trop de précision. On utilise une orthogonalisation de Löwdin suivie d'une approximation NDDO. Les intégrales biélectroniques tri et quadricentriques sont estimées par un développement tronqué de Ruedenberg. Toutes les intégrales monoélectroniques sont évaluées exactement. Aucun paramètre empirique n'est employé. Des essais numériques sur CO, OF2, O3 et ONF montrent que l'approximation NDDO est très précise pour les fonctions de Löwdin et que le développement de Ruedenberg est numériquement satisfaisant pour les calculs SCF MO.
    Notes: Abstract A method is described for reducing a large part of the arithmetic of exact ab-initio SCF molecularorbital calculations based on Slater-type-orbitals without noticeable loss of numerical accuracy. The procedure involves the transformation to Löwdin orthogonalized orbitals and then invoking the NDDO approximation. The three- and four-centre two-electron integrals required are estimated by a truncated Ruedenberg expansion. All one-electron integrals are evaluated exactly. No empirical parameters are employed. Numerical tests on CO, OF2, O3 and ONF show that the NDDO approximation is very accurate for Löwdin functions and that the Ruedenberg expansion is arithmetically satisfactory for the SCF MO calculations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00529129
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  • 14
    Electronic Resource
    Electronic Resource
    Inhibitors of the dicarboxylate and tricarboxylate transporting systems of rat liver mitochondria (1972)
    Springer
    The journal of membrane biology 7 (1972), S. 391-401 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary A large number of compounds were tested for their effectiveness as inhibitors of the tricarboxylate and dicarboxylate transporting systems of rat liver mitochondria as monitored by citrate/[14C] citrate exchange and phosphate/[14C]l-malate exchange, respectively. The influence of inhibitor structure on inhibitory potency is discussed for each transporting system and deductions made concerning the nature of the binding sites of these carrier systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01867928
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  • 15
    Electronic Resource
    Electronic Resource
    Simplified ab-initio calculations on hydrogen-containing molecules (1971)
    Springer
    Theoretical chemistry accounts 21 (1971), S. 205-210 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The simplified ab-initio method described in an earlier paper is tested on some hydrogen-containing molecules. The performance is slightly below that found previously for molecules composed entirely of first-row atoms but should be suitable for applications where limited numerical accuracy is sufficient. The hope of improved performance through limited expansion of the basis, especially on hydrogen, is not realised and so alternative treatments of the two-electron many-centre integrals should be sought if greater numerical accuracy is required.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00530219
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  • 16
    Electronic Resource
    Electronic Resource
    The coupling of biogeochemical cycles of nutrients (1987)
    Springer
    Biogeochemistry 4 (1987), S. 61-75 
    Details
    ISSN: 1573-515X
    Keywords: Biogeochemical cycles ; nutrient cycle interactions ; ecosystem dynamics ; ecosystem perturbation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract For any element which is incorporated into biomass, the biogeochemical cycle of that element in a given ecosystem will be coupled to that of any other element similarly incorporated. The mutual interaction of two such cycles is examined using a simple model in which each cycle is constrained into four compartments. In each cycle the assimilation rate (primary productivity) is related in a non-linear fashion to the two nutrients and to biomass. The interactions are represented by combining a hyperbolic dependence for each nutrient (involving a "Michaelis constant") with a logistic equation governing the dependence of rate on biomass (involving a "carrying capacity"). The response of the model to perturbation (e.g. mobilization of an abiotic reserve) is strongly governed by the values assigned to these constants. The coupled cycles can exhibit positive feed-back with anomalous responses of the steady state and time-dependent solutions may exhibit complex oscillatory behaviour. Both the steady-state sensitivity and the kinetic behaviour of such coupled systems are simplified if the range of atomic ratios permitted by the assimilation process is restricted. It will therefore be of importance to determine under what conditions the assimilation rates for different elements are governed by mass-action effects (Liebig's Law) or by stoichiometric constraints (Redfield ratios).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02187362
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  • 17
    Electronic Resource
    Electronic Resource
    LINKING AIR ISSUES WITH DOSE-RESPONSE AND BIOGEOCHEMICAL-CYCLE MODELS (1997)
    Springer
    Environmental monitoring and assessment 46 (1997), S. 59-71 
    Details
    ISSN: 1573-2959
    Keywords: dose-response relationship ; linked environmental issues
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This paper describes the roles that dose-response andbiogeochemical-cycle models play in the comparative and integratedassessment of several atmospheric issues. The two approaches aredescribed briefly, as they are commonly used, and as they might beapplied when multiple stressors and receptors, and when interactingcycles, respectively, are involved. Examples are drawn from thecarbon and sulfur cycles to demonstrate how knowledge of a cycleprovides a useful link among various current pollution issues. Possibleinteractions and some shortcomings of the two approaches are given,leading to suggestions for the appropriate use of the two tools forscientific analysis and policy development for the various air issues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005731817973
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  • 18
    Electronic Resource
    Electronic Resource
    Binding energies at different momenta for the valence orbitals of HCl by the binary (e, 2e) method (1980)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 18 (1980), S. 275-280 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The binding energy spectra for the valence orbitals of hydrogen chloride have been obtained using the binary (e,2e) method at 1200 eV. The strength of the innermost valence orbital (4σ) is severely split among several ion states in the energy range 25 to 41 eV. The measured cross sections are compared with results of calculations using contracted Gaussian basis sets of double-zeta quality, and with a one-particle Green's function calculation.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560180138
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  • 19
    Electronic Resource
    Electronic Resource
    A theoretical study of the hyperpolarisabilities of nickel dithiolene molecules (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 1 (1992), S. 221-228 
    Details
    ISSN: 1057-9257
    Keywords: Hyperpolarisabilities ; Nickel Dithiolene ; Non-linear optical properties ; CNDO method ; Finite field method ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The hyperpolarisabilities γ of nickel dithiolene complexes have been calculated by the finite field method in combination with the CNDO/S molecular orbital method. This computational technique, which has been developed for calculating the polarisation of large organic molecules by a perturbing electric field, is discussed. The changes in γ that occur as a result of different selections of substituent groups in the dithiolene ligand are described. The results are compared with recent experiments investigating these types of molecules. Large values for γ are found to arise from the interaction of the nickel 3d electrons with the conjugated π-electrons of the metal-ligand complex.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/amo.860010503
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