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  • 1
    Electronic Resource
    Electronic Resource
    The filling mechanism of the swimbladder (1963)
    Springer
    Cellular and molecular life sciences 19 (1963), S. 497-511 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Es wird gezeigt, dass die Erzeugung der hohen Gasdrucke, welche in der Schwimmblase von Tiefseefischen beobachtet werden, durchVervielfachung bekannter Konzentrier-Einzeleffekte in der durch das rete mirabile gegebenen Haarnadelgegenstromvorrichtung möglich ist. Der Konzentrier-Einzeleffekt — eine kleine Erhöhung der Gaskonzentration in den afferenten relativ zu benachbarten efferenten Kapillarelementen — dürfte bei allen Gasen durch eine geringe Erhöhung der Elektrolytkonzentration (Aussalzwirkung) zustande kommen. Im Falle von Sauerstoff überlagern sich der Aussalzwirkung bei Zusatz von Milchsäure die durch pH-Verschiebung bedingten Bohr- und Rooteffekte, wobei die Substanzen dem Blut am Scheitel des rete durch die dort befindliche Drüse zugefügt werden. Auf Grund der vorliegenden Berechnungen, die sich auf die beim Aal gegebenen Verhältnisse stützen, würde eine relative Erhöhung des Salzgehaltes um 0,02M/I im Falle von Stickstoff einen Einzeleffekt erzeugen, aus welchem infolge der durch das rete bewirkten Vervielfachung ein Partialdruck von etwa 25 Atm N2 aufgebaut werden könnte. Eine relative Erhöhung des Milchsäuregehaltes in den efferenten Kapillaren um 45 mg% (beim Aalin vivo experimentell bestätigt) müsste für Sauerstoff einen Einzeleffekt hervorbringen, der bis zu Enddrucken von ∼ 3000 Atm multipliziert werden kann. Die genaue Analyse lässt in diesem Fall erkennen, dass bei niedrigen Partialdrücken der Bohr- und Rooteffekt, und nach Erreichung hoher O2-Drücke, der Aussalzeffekt den im Gegenstrom vervielfachten Einzeleffekt bildet. Es wird ein Modellversuch beschrieben, bei welchem die Anreicherung eines Gases durch Vervielfachung des Aussalzeffektes in einer Gegenstromvorrichtung tatsächlich durchgeführt wurde. Es wird weiter darauf hingewiesen, dass der Vorgang im Gesamteffekt einenaktiven Transport darstellt und es wird die Herkunft der für einen solchen Vorgang benötigten freien Energie durch eine thermodynamische Betrachtung aufgezeigt. Im übrigen wurde versucht, die allgemeinen Prinzipien der Gegenstrom-Multiplikation verständlich zu machen, und bestehende Theorien über die Gaskonzentrierung in der Schwimmblase wurden im Lichte dieser Erkenntnisse einer sachlichen Diskussion und Kritik unterworfen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02150881
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  • 2
    Electronic Resource
    Electronic Resource
    Organochlorine pesticides in anhingas, white ibises, and apple snails collected in Florida, 1989–1991 (1996)
    Springer
    Archives of environmental contamination and toxicology 30 (1996), S. 379-383 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Apple snails (Pomacea paludosa) and eggs and nestlings of anhingas (Anhinga anhinga) and white ibises (Eudocimus albus) were collected in Palm Beach County, Florida from 1989–1991 and analyzed for organochlorine pesticide (OCP) residues. Pesticide residues were not detected in the apple snails. Residues of DDT, with maximum concentrations of 1,200 μg/kg wet weight occurred in 50% of the ibis samples but were not present in the anhinga samples. DDE occurred in 100% of avian samples at concentrations up to 2,100 μg/kg and was at significantly greater concentration in the anhingas. Dieldrin was not detected in the first year of the three-year study, but occurred in the majority of avian samples in the last two years at concentrations up to 610 μg/kg. Additionally, residues of seven pesticides and Aroclor® 1016 were detected infrequently at very low concentrations in the birds. While it is possible that nearby municipal solid waste landfills were the source of the pesticides, no corroborating evidence was found to support this speculation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212297
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  • 3
    Electronic Resource
    Electronic Resource
    Organochlorine Pesticides in Anhingas, White Ibises, and Apple Snails Collected in Florida, 1989–1991 (1996)
    Springer
    Archives of environmental contamination and toxicology 30 (1996), S. 379-383 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Apple snails (Pomacea paludosa) and eggs and nestlings of anhingas (Anhinga anhinga) and white ibises (Eudocimus albus) were collected in Palm Beach County, Florida from 1989–1991 and analyzed for organochlorine pesticide (OCP) residues. Pesticide residues were not detected in the apple snails. Residues of DDT, with maximum concentrations of 1,200 μg/kg wet weight occurred in 50% of the ibis samples but were not present in the anhinga samples. DDE occurred in 100% of avian samples at concentrations up to 2,100 μg/kg and was at significantly greater concentration in the anhingas. Dieldrin was not detected in the first year of the three-year study, but occurred in the majority of avian samples in the last two years at concentrations up to 610 μg/kg. Additionally, residues of seven pesticides and Aroclor® 1016 were detected infrequently at very low concentrations in the birds. While it is possible that nearby municipal solid waste landfills were the source of the pesticides, no corroborating evidence was found to support this speculation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002449900051
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  • 4
    Electronic Resource
    Electronic Resource
    Membrane-bound Na+,K+-ATPase as the cardiac glycoside receptor (1997)
    Springer
    Journal of thermal analysis and calorimetry 48 (1997), S. 437-445 
    Details
    ISSN: 1572-8943
    Keywords: cardiac glycoside binding ; DSC ; membrane protein ; membrane receptor binding ; Na+ ; K+-ATPase ; thermal unfolding ; titration calorimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract DSC studies are carried out to characterize Na+,K+-ATPase isolated from pig kidney in its natural membrane environment as well as in its purified state upon detergent treatment. The transition temperatures of the investigated thermal protein unfolding process, observed between 43 and 64.5° C, depend on the local membrane environment as well as onpH. In addition, the transition temperature is significantly increased upon binding of different cations and ligands which are known to interact with the enzyme. Evidence for a lipid phase transition around 23 °C in the original biological membrane is reported. The application of a calorimeter equipped with removable cells appears to be more suitable for the investigation of this type of membrane sample than an instrument with fixed capillary cells. Filling the sample capillary cell with an usual syringe, consisting of a long and thin needle, can influence the experimental results. Na+, K+ -ATPase acts as the receptor for cardiac glycoside binding. The thermodynamic parameters of this binding process are determined by titration calorimetry. The binding of ouabain, as a typical example, is unusually slow and is enthalpy driven. The enthalpy change upon binding enthalpy is −75 kJ mol−1 at 25 °C. The surprisingly low stoichiometric coefficient, resulting from an evaluation based on a simple one step binding model, is interpreted in terms of a dimeric receptor unit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01979490
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  • 5
    Electronic Resource
    Electronic Resource
    Comparison of Experimental Methods and Theoretical Calculations on Crystal Energies of ‘Isoenergetic’ Polymorphs of Cimetidine (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 7-22 
    Details
    ISSN: 1572-8943
    Keywords: crystal modifications ; DSC ; Gibbs free energy function ; molecular modelling ; solution calorimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermodynamic energy relationship between two crystal modifications of cimetidine was investigated and compared with differences in their processing properties with respect to transformation from one modification to the other. The crystal energies of the two modifications A and D were found to be almost identical and therefore the polymorphs are regarded as virtually isoenergetic crystals. This statement is based on DSC measurements of the melting points and of the enthalpies of fusion for the two crystal forms, which enable the calculation of the Gibbs free energy functions. Furthermore, the statement is supported by measurements of the enthalpies of solution in two different solvents. Both DSC and solution experiments reveal a slightly higher stability of the D modification with respect to the A form. In addition, tribomechanical treatment also indicates modification D to be the more stable one, as well as the higher density of the D form. No transformation during DSC at low heating rate was found which could be used in a stability consideration. As the explicit crystal structures of the two modifications are resolved, it was possible to calculate crystal energies theoretically as well. The theoretical results showed a remarkable difference in the crystal energies at zero degree Kelvin. Furthermore, they were just contradicting experimental findings by stating A being more stable than D. Possible reasons for this discrepancy and the feasibility of today's calculation methods with respect to prediction of stability properties are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010137505058
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  • 6
    Electronic Resource
    Electronic Resource
    Applied chemical thermodynamics and kinetics on pharmaceutical compounds (1988)
    Springer
    Journal of thermal analysis and calorimetry 33 (1988), S. 37-45 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird die wichtige Rolle thermoanalytischer Methoden auf dem Gebiet der pharmazeutischen und galenischen Forschung betont und die thermodynamische Stabilität polymorpher Formen von Substanzen besprochen.
    Abstract: Резуме В общих чертах описан а важная роль термоаналитических методов в исследован ии фармацевтических и п риродных веществ. Обс уждена термодинамическая у стойчивость полимор фных форм вещества.
    Notes: Abstract The important role of thermoanalytical methods in the field of pharmaceutical and galenic research is outlined. The thermodynamic stability of polymorphic forms of a substance is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01914582
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  • 7
    Electronic Resource
    Electronic Resource
    Preface (1991)
    Springer
    Journal of thermal analysis and calorimetry 37 (1991), S. 1629-1630 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01912191
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  • 8
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    The filling mechanism of the swimbladder (1963)
    Springer
    Details
    Publication Date: 1963-10-01
    Print ISSN: 0014-4754
    Topics: Biology , Medicine
    Published by Springer
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  • 9
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    Increased Dynamic Effects in a Catalytically Compromised Variant of Escherichia coli Dihydrofolate Reductase (2013)
    American Chemical Society (ACS)
    Details
    Publication Date: 2013-11-27
    Description: Journal of the American Chemical Society DOI: 10.1021/ja410519h
    Print ISSN: 0002-7863
    Electronic ISSN: 1520-5126
    Topics: Chemistry and Pharmacology
    Published by American Chemical Society (ACS)
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  • 10
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    Contraction, fragmentation and expansion dynamics determine nutrient availability in a Mediterranean forest stream (2011)
    Springer
    Details
    Publication Date: 2011-04-29
    Print ISSN: 1015-1621
    Electronic ISSN: 1420-9055
    Topics: Biology
    Published by Springer
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