994 resultados para HS-DSC


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Conventional differential scanning calorimetry (DSC) techniques are commonly used to quantify the solubility of drugs within polymeric-controlled delivery systems. However, the nature of the DSC experiment, and in particular the relatively slow heating rates employed, limit its use to the measurement of drug solubility at the drug's melting temperature. Here, we describe the application of hyper-DSC (HDSC), a variant of DSC involving extremely rapid heating rates, to the calculation of the solubility of a model drug, metronidazole, in silicone elastomer, and demonstrate that the faster heating rates permit the solubility to be calculated under non-equilibrium conditions such that the solubility better approximates that at the temperature of use. At a heating rate of 400°C/min (HDSC), metronidazole solubility was calculated to be 2.16 mg/g compared with 6.16 mg/g at 20°C/min. © 2005 Elsevier B.V. All rights reserved.

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The preparation and characterization of two new neutral ferric complexes with desolvation-induced discontinuous spin-state transformation above room temperature are reported. The compounds, Fe(Hthpy)(thpy).CH3OH.3H2O (1) and Fe(Hmthpy)(mthpy).2H2O (2), are low-spin (LS) at room temperature and below, whereas their nonsolvated forms are high-spin (HS), exhibiting zero-field splitting. In these complexes, Hthpy, Hmthpy, and thpy, mthpy are the deprotonated forms of pyridoxal thiosemicarbazone and pyridoxal methylthiosemicarbazone, respectively; each is an O,N,S-tridentate ligand. The molecular structures have been determined at 100(1) K using single-crystal X-ray diffraction techniques and resulted in a triclinic system (space group P1) and monoclinic unit cell (space group P21/c) for 1 and 2, respectively. Structures were refined to the final error indices, where RF = 0.0560 for 1 and RF = 0.0522 for 2. The chemical inequivalence of the ligands was clearly established, for the "extra" hydrogen atom on the monodeprotonated ligands (Hthpy, Hmthpy) was found to be bound to the nitrogen of the pyridine ring. The ligands are all of the thiol form; the doubly deprotonated chelates (thpy, mthpy) have C-S bond lengths slightly longer than those of the singly deprotonated forms. There is a three-dimensional network of hydrogen bonds in both compounds. The discontinuous spin-state transformation is accompanied with liberation of solvate molecules. This is evidenced also from DSC analysis. Heat capacity data for the LS and HS phases are tabulated at selected temperatures, the values of the enthalpy and entropy changes connected with the change of spin state were reckoned at DeltaH = 12.5 0.3 kJ mol-1 and DeltaS = 33.3 0.8 J mol-1 K-1, respectively, for 1 and DeltaH = 6.5 0.3 kJ mol-1 and DeltaS = 17.6 0.8 J mol-1 K-1, respectively, for 2

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; alte Signatur: Hs. in Quart 107

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; Akzessionsnummer: x20230

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; alte Signatur: Hs. in Quart 106

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; alte Signatur: Hs. in Quart 115

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; alte Signatur: Hs. in Quart 104; Hs in 4° 104

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; alte Signatur: Hs. in Quart 105; Hs in 4° 105

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; alte Signatur: Hs. in Quart 108

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; alte Signatur: Hs. in Quart 114

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Vorbesitzer: Freiherrlich Carl von Rothschild'sche Bibliothek Frankfurt am Main; alte Signatur: Hs. in Quart 109

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Vorbesitzer: Moritz Abendroth; Fräulein Abendroth; Freiherrlich Carl von Rothschild'sche öffentliche Bibliothek; alte Signatur: Hs. in Oktav 57; Hs in 8° 57

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Die AQ Austria ist durch das Hochschul-Qualitätssicherungsgesetz (HS-QSG) beauftragt, alle drei Jahre einen Bericht zur Entwicklung der Qualitätssicherung an hochschulischen Bildungseinrichtungen zu erstellen. In diesem ersten Bericht werden Gemeinsamkeiten und Spezifika der drei Hochschulsektoren – öffentliche Universitäten, Privatuniversitäten und Fachhochschulen – bei der Gestaltung des internen Qualitätsmanagements sowie bei den Maßnahmen der Qualitätssicherung und –entwicklung aufgezeigt. Die aktuellen Themenbereiche und Fragestellungen sind in die nationalen Rahmenbedingungen eingebettet, innerhalb derer die österreichischen Hochschulen agieren und die die Qualitätssicherung an den österreichischen Hochschulen mitbestimmen.