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  • 1990-1994  (183)
  • 1970-1974  (80)
  • 1830-1839  (10)
  • Chemistry  (268)
  • absorption
  • 1
    Electronic Resource
    Electronic Resource
    The kinetics of diastereomeric amino acids with o-phthaldialdehyde (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 3 (1991), S. 471-475 
    Details
    ISSN: 0899-0042
    Keywords: amino acids ; kinetics ; epimers ; OPA ; postcolumn reaction detection ; fluorescence detection ; amino acid racemization ; dating methods ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the reaction of the amino acid epimers L-isoleucine, D-alloisoleucine, L-threonine, and D-allo-threonine with o-phthaldialdehyde and mercaptoethanol were determined at 25°C. L-Isoleucine reacts faster than its D-epimer whereas L-threonine reacts slightly slower than its D-epimer. In the case of isoleucine, the consequence can be an allo/iso ratio which in the worst case is 25% too low if these amino acids are quantified by liquid chromatography and o-phthaldialdehyde fluorescence detection. The effect on dating of fossils by amino acid racemization is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530030611
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  • 2
    Electronic Resource
    Electronic Resource
    Über ein Oxidchlorid des Calciums: Ca4OCl6 (1991)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 596 (1991), S. 89-92 
    Details
    ISSN: 0044-2313
    Keywords: Calcium oxychloride ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: An Oxychloride of Calcium: Ca4OCl6Ca4OCl6 (hexagonal, P63mc, Z = 2), a = 905.8(3), c = 686.3(4) pm, (R = 0.031) crystallizes as colourless needles from reducing melts (CaCl2, Ca) that contain small amounts of „oxygen“. It contains „isolated“ tetrahedral units [Ca4O] and is isotypic with e.g., Ba4OCl6, Yb4OCl6 and K6HgS4. Ca4OCl6 does not form in the dehydration process of, for example, CaCl2 · 6 H2O.
    Notes: Ca4OCl6 (hexagonal, P63mc, Z = 2, a = 905.8(3)); c = 686.3(4) pm, (R = 0,031) kristallisiert in Form farbloser Nadeln aus „reduzierenden Schmelzen“ (CaCl2, Ca), die wenig „Sauerstoff“ enthalten. Es enthält „isolierte“ tetraedrische [Ca4O]-Einheiten und ist isotyp mit z. B. Ba4OCl6, Yb4OCl6 oder K6HgS4. Ca4OCl6 entsteht nicht beim Entwässern von z. B. CaCl2 · 6 H2O.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19915960112
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  • 3
    Electronic Resource
    Electronic Resource
    Automatisierte segmentale Dünndarmperfusion (1971)
    Springer
    Journal of molecular medicine 49 (1971), S. 1218-1222 
    Details
    ISSN: 1432-1440
    Keywords: Small intestine ; absorption ; methods ; Dünndarm ; Resorption ; Methoden
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über eine neu entwickelte automatisierte Methode der segmentalen Dünndarmperfusion berichtet, die ein dreilumiges Sondensystem (Ingelfinger et al.) verwendet. Durch die erreichte Vereinfachung der Technik erscheint es möglich, diese Methode jetzt auch in Kliniken, vor allem in der speziellen gastroenterologischen Diagnostik einzusetzen. An Hand von Mehrfachmessungen am gleichen Patienten wird die Reproduzierbarkeit der Ergebnisse und die Validität der Methodik herausgestellt und ihr Vorteil gegenüber bisher gebräuchlichen Verfahren diskutiert.
    Notes: Summary An automatic perfusion system for segmental measurements of intestinal absorption is described. This makes use of the triple-lumen tube according to Ingelfinger and coworkers. Its application for diagnostic procedures in routine gastroenterology is shown. The reliability of the data obtained is demonstrated by repeated measurements in the same patient. The advantage of this method is discussed in comparison with the techniques hitherto used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01732730
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Frage der Resorption von Silymarin bei der Ratte (1972)
    Springer
    Journal of molecular medicine 50 (1972), S. 1060-1061 
    Details
    ISSN: 1432-1440
    Keywords: Silymarin ; absorption ; rats ; Silymarin ; Resorption ; Ratten
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Mittels eines von Wagner, Hörhammer und Seitz [2] angegebenen spektrophotometrischen Verfahrens wurde nach Applikation hoher Dosen Silymarin bei der Ratte nachgewiesen, daß rund 75% wieder im Kot ausgeschieden werden. Ein Nachweis von Silymarin im Serum und im Urin sowie im Leberhomogenisat gelang mit der angegebenen Methode nicht.
    Notes: Summary In rats, large amounts of Silymarin (about 75%) will be excreted in the faces. This could be demonstrated with the spectroscopic method of Wagner, Hörhammer and Seitz [2]. The method applied did not permit to demonstrate the presence of Silymarin in serum, urine or liver homogenates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01486769
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  • 5
    Electronic Resource
    Electronic Resource
    The relationship between structure and function of small intestine in patients with a sprue syndrome and in healthy controls (1973)
    Springer
    Journal of molecular medicine 51 (1973), S. 1151-1158 
    Details
    ISSN: 1432-1440
    Keywords: Small intestine ; sprue-syndrome ; absorption ; relationship with mucosal structure ; Dünndarm ; Sprue-Syndrom ; Resorption ; Beziehung zur Schleimhautstruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde die Beziehung zwischen Funktionsstörung und Schleimhautumbau des Dünndarms bei Patienten mit einem Sprue-Syndrom vor und nach Behandlung untersucht. Diese Befunde wurden denen eines normalen Kontrollkollektivs gegenübergestellt. Darüber hinaus wurde der Gehalt einiger histochemisch nachweisbarer Enzymaktivitäten des Resorptionsepithels semiquantitativ abgeschätzt. Als Parameter der Schleimhautoberfläche wurde die Zottenhöhe, der Zottenumfang pro mm Darmlänge und die Epithelzellzahl pro mm Darmlänge herangezogen. Als Parameter der Transportfunktion wurde die Glucose-, Elektrolyt-und Wasserresorption mittels einer automatisierten dreilumigen Sondentechnik gemessen. Ergebnisse. 1. Die Glucoseresorption der Patienten mit dem unbehandelten Sprue-Syndrom beträgt weniger als 20%, die der behandelten Patienten weniger als 60% der Kontrollen. 2. Der Natrium-, Kalium- und Wassertransport ist bei den unbehandelten Patienten im Sinne einer Sekretion in das Lumen umgekehrt. Diese Umkehr ist bei den behandelten Patienten für Wasser und Natrium nicht nachweisbar, für Kalium jedoch unverändert vorhanden. 3. Zwischen der Glucose-, Natrium-, Kalium- und Wasserresorption einerseits und der Zottenhöhe, dem Zottenumfang pro mm Darmlänge und der Epithelzellzahl pro mm Darmlänge andererseits besteht eine hochsignifikante lineare Beziehung. 4. Der Enzymgehalt des Resorptionsepithels ist beim Sprue-Syndrom erwartungsgemäß herabgesetzt. Nach den korrelierenden morphologischen und funktionellen Befunden scheint die Transportminderung jedoch vorwiegend zu Lasten der reduzierten Resorptionsfläche zu gehen.
    Notes: Summary The relationship between structure and function of the small intestinal mucosa has been studied in treated and untreated sprue and in normal individuals. Glucose, electrolyte and water absorption, as well as histochemically detectable enzymatic activities, have been employed as functional parameters. Villus circumference and height, crypt length and the number of absorptive cells per unit length were used to indicate structural change. Results: 1) Glucose absorption was less than 20% of the control value in patients with untreated sprue and less than 60% in treated sprue. 2) Sodium, potassium and water transport in the untreated condition was reversed, i.e. secreted into the lumen. After treatment, potassium was still secreted, but water and sodium were again absorbed. 3) A highly significant linear relationship existed between glucose, sodium, potassium and water absorption on the one hand, and villus height as well as villus circumference and number of absorptive cells per mm length of intestine on the other. 4) The enzymatic activities of the absorptive cells were reduced. However, according to statistical analysis of the structural and functional data, the observed reduction in transport seemed to be mainly related to decreased surface area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01468564
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  • 6
    Electronic Resource
    Electronic Resource
    Tannic acid inhibition of amino acid and sugar absorption by mouse and vole intestine: Tests following acute and subchronic exposure (1992)
    Springer
    Journal of chemical ecology 18 (1992), S. 719-736 
    Details
    ISSN: 1573-1561
    Keywords: Dietary tannins ; tannic acid ; digestion ; absorption ; small intestine ; brush border membrane ; unstirred layer ; mucus ; Microtus, Mus.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The acute effects of tannin (tannic acid; TA) on nutrient absorption were studied by measuring sugar and amino acid uptake across the brash border (luminal membrane) of intact intestine in the presence and absence of TA. Incubation of tissue for 4–9 min in TA solution (1 mg/ml) caused a reduction in passive influx ofl-glucose in voles and mice and a reduction in carrier-mediated influx ofd-glucose and total influx ofl-proline in mice, but not voles. In subchronic experiments, mice and voles were fed for 7–14 days a diet with 4% TA, but there was no significant effect on intestinal brush border uptake ofl-glucose,d-glucose, orl-proline (or three other amino acids tested in voles). In a synthesis of our study with others in the literature, three inferences are made from the patterns of effects across solutes, time scales of exposure, and species. First, the transport inhibitory effects following acute exposure are probably mediated by two processes: increased resistance to passive flux across an effective unstirred layer juxtaposed to the brush border membrane, perhaps due to tannin-mucin binding, and reduced Na+-coupled nutrient uptake across the intestinal brush border. Second, there is a species sensitivity difference in TA's effect on the second process. Third, the negative effects observed at the acute time scale in vitro do not necessarily occur in animals eating TA subchronically because little TA reaches the luminal membrane, or if it does its effects are quickly reversed when the tissue is removed and washed with solution free of TA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00994610
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  • 7
    Electronic Resource
    Electronic Resource
    Thermodynamic cycle-perturbation study of the binding of trifluoroacetyl dipeptide anilide inhibitors with porcine pancreatic elastase (1990)
    New York : Wiley-Blackwell
    Biopolymers 30 (1990), S. 773-780 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The variety of results of crystallographic studies of the serine proteases complexed with isocoumnrin inhibitors presents a challenging problem to modeling methods and molecular energetics. Therefore, the thermodynamic cycle-perturbation technique has been used to study a model system of elastase and two peptidic inhibitors. Using the program AMBER, the technique correctly predicts changes of the binding constants for the trifluoroacetyl dipeptide inhibitors in comparison with available experimental (kinetic and crystallographic) data. However, the absolute values obtained are shown to be sensitive to the specific electrostatic interaction potential parameters used in the simulations. The reader and user are cautioned that thermodynamic cyle-perturbation results may be too optimistic by underestimating the accuracy of free energy values. This is especially a matter of concern for those cases where a direct comparison with experimental values is not possible, viz., (1) the simulation of binding of novel compounds, (2) structurally uncertain binding sites, or (3) structurally different binding modes. With our best 4-31G* ESP (electrostatic potential) charges we were able to reproduce experimentally determined free energy differences (ΔΔA) with an accuracy of about 1.5 kcal/mol. Dynamically induced structural changes in the binding site of elastase, and particularly changes in hydrogen-bond patterns of the binding site, are also reported.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360300712
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  • 8
    Electronic Resource
    Electronic Resource
    Correlation between microscopic structural parameters and macroscopic flow behaviour of some polymer-surfactant systems suitable for tertiary oil recovery (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 195 (1992), S. 57-77 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Einige für den kombinierten Polymer-Tensid-Einsatz in der tertiären Erdölförderung (EOR) diskutierte Substanzen wurden mittels statischer und dynamischer Lichtstreuung charakterisiert und bezüglich ihrer Anwendbarkeit in unterschiedlich salinaren Modellwässern durch rheologische und rheologisch-dynamische Messungen unter-sucht.Als Polymere wurden Xanthan sowie unterschiedlich hydrolysierte Polyacrylamide verwendet, als Tensid ein Ethylenglykolsulfonat. Es ließen sich Korrelationen zwischen mikroskopischen Strukturparametern (z. B. hydrodynamischer Radius, Trägheitsradius, Molekulargewicht, Gestaltparameter der gelösten Polymeren) und makroskopischem Verhalten wie Viskosität aufstellen, welche für den EOR-Einsatz wichtige rheologische Parameter darstellen.Mit ergänzenden Messungen (Oberflächenspannung, zeitabhängiges Viskositätsverhalten) können Aussagen über die Effizienz und Langzeitstabilität eingesetzter Polymer-Tensid-Slugs in unterschiedlich salinaren Lagerstätten gemacht werden.
    Notes: Some materials, suitable for application in polymer-surfactant flooding used in tertiary oil recovery (EOR), have been characterized by static and dynamic light scattering and studied in respect to their suitability in various model brines by measuring their rheological and dynamic-rheological behaviour. Xanthan and polyacrylamides of different degree of hydrolysis have been used as polymers, an ethylene glycol sulfonate as surfactant.Correlations have been established between microscopic structural parameters (Hydrodynamic radius, radius of gyration, molar mass, shape of the polymers) and the macroscopic behaviour, such as viscosity and elasticity, being important rheological parameters for EOR application. Additional investigations on surface tension and long term viscosity study lead then to a judgement for the efficiency and long term stability of polymer-surfactant slugs in various reservoirs of different salinity.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051950104
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  • 9
    Electronic Resource
    Electronic Resource
    Model connective tissue systems. A physical study of gelatin gels containing proteoglycans (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 1351-1364 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The swelling behavior of gelatin gels containing proteoglycans (sulphated proteoglycans from bovine intervertebral discs and a hyaluronate proteoglycan from bovine synovial fluid) when immersed in osmotically active solutions of dextran have been measured. The presence of the proteoglycans markedly affects the internal osmotic contribution to the swelling pressure of the gel. These internal osmotic pressures are considerably in excess of the sum of the osmotic activities of the individual components. This behavior is understood in terms of an entropic interaction between the gelatin and the proteoglycan molecules. By use of the “dilute solution” treatment of Flory, the osmotic pressure excesses are related to the volumes and hence dimensions of the interact acting species. A comparison of these values with those calculated by other means shows good agreement. The osmotic behavior of the complex gels can be understood on a mechanistic basis, if we regard the gelatin and sulphated proteoglycans as spheres and the hyaluronate proteoglycan as a rod.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100808
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  • 10
    Electronic Resource
    Electronic Resource
    Glykoside von Aminozuckern, II. Zur Synthese von 2-Amino-2-desoxy-α-D-glucopyranosiden (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 1792-1796 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Glycosides of Amino Sugars, II. Synthesis of 2-amino-2-deoxy-α-D-glucopyranosidesThe synthesis of glycosides and disaccharides of 2-amino-2-deoxy-D-glucose has been explored using trifluoroacetyl as the N-blocking group. Because of its high tendency for neighboring group participation only β-D-glycosides were formed. The corresponding α-disaccharide could be obtained as the main product when employing 2.4-dinitrophenyl as the N-protecting group.
    Notes: Die N-Trifluoracetyl-Schutzgruppe wurde zur Synthese von Glykosiden und Disacchariden der 2-Amino-2-desoxy-D-glucose benutzt. Sie zeigte eine hohe Tendenz zur Nachbargruppen-beteiligung unter Bildung von -β-D-Glykosiden. Das entsprechende α-Disaccharid wurde als Hauptprodukt bei Verwendung der N-2.4-Dinitrophenyl-Schutzgruppe erhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030614
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