Controlled release of goserelin from microporous polyglycolide and polylactide

Two microporous biodegradable polyesters, i.e., PGA and PDLLA, were obtained by solid-state polymerization reaction from the sodium salts of the corresponding alpha-hydroxycarboxylic acids after washing out the by-product sodium chloride. The polymers were shaped by cold uniaxial pressing, by hot uniaxial pressing, and by extrusion at elevated temperature. Due to the special microporosity of the polymers, the introduction of drugs is possible at moderate temperature. The release kinetics of the model drug Phe and of the anti-tumor drug goserelin (an LH-RH agonist) from compacted polymer samples were fast (approx. 2 d). The release kinetics of goserelin were corrected for the decomposition of the drug. External coatings with PDLLA or PLLA obtained by immersion in polymer solution strongly slowed down the release kinetics in the case of the PDLLA coating, giving an almost linear release during 100 d. A coating with PLLA was unsuitable to slow down the release kinetics.     

Untersuchungen an quaternären Fluoriden LiMIIMIIIF6, Über die Kationenverteilung in Fluortrirutilen

Inhaltsübersicht. Fluortrirutile LiM^IIM^IIIF₆ kristallisieren tetragonal in dor Raumgruppe P4₂/mnm mit Li in Position (2a) und M^II und M^III statistisch vorteilt in (4e). An Einkristallen und durch Pulvermessungen wurde die Verteilung der Kationen untersucht, wozu die neu dargestellte Rhodiumverbindung LiZnRhF₆ auf Grund des unterschiedlichen Streuvermögens der Kationen besonders geeignet war. Verbindungen LiCuM^IIIF₆ zeigen die einfache Rutilstruktur. Investigations of the Quaternary Fluorides LiM^IIM^IIIF₆. On the Distribution of Cations in Fluorotrirutiles Abstract. Trirutiles LiM^IIM^IIIF₆ crystallize tetragonally in the space group P4₂/mnm with Li in position (2a) und M^II and M^III statistically distributed in (4e). By single-crystal X-Ray diffraction and by powder work cation ordering was examined for which the new compound LiZnRhF, was especially adapted. Compounds LiCuM^IIIF₆ are disordered rutile phases.     

Improvement,validation and application of CFD/DEM model to dense gas–solid flow in a fluidized bed

Dense gas–solid flow with solid volume fraction greater than 10% and at moderate Reynolds number is important in many industrial facilities such as fluidized beds. In this work, the Euler–Lagrange approach in combination with a deterministic collision model is applied to a laboratory-scale fluidized bed. The fluid–particle interaction is studied using a new procedure called the offset method, which results in several numbers of spatial displacements of the fluid grid. The proposed method is highly precise in determining porosity and momentum transfer, thus improving simulation accuracy. A validation study was carried out to assess the results using this in-house CFD/DEM code against 5-s operation of a Plexiglas spouted-fluidized bed, showing good qualitative correlation of solid distribution in the bed and acceptable quantitative agreement of pressure drops at different positions in the bed. In view of high computing cost, special emphasis is placed on effective program design, such as application of advanced detection algorithm for particle–particle/wall collisions, the multi-grid method and parallel calculation. In this context, the influence of increasing the processor number, up to 36, on calculation efficiency was investigated.     

Genies, Ideen, Institutionen, mathematische Werkstätten: Formen der Mathematikgeschichte

Zusammenfassung. Der Essay diskutiert einige g?ngige Formen der Mathematikgeschichtsschreibung wie Biographie, Ideengeschichte und Institutionengeschichte. Im Anschluss daran wird die vom Autor befürwortete Form der Geschichtsschreibung skizziert. Diese orientiert sich an neueren Tendenzen der Wissenschaftsgeschichte, Wissenschaft als (Forschungs-)Praxis zu beschreiben. Zur Illustration der M?glichkeiten und Probleme der diskutierten historiographischen Formen dienen Beispiele aus der Geschichte der Knotentheorie. Eingegangen am 30. September 1999 / Angenommen am 9. Juni 2000     

Covalent Attachment of Aggregation-Induced Emission Molecules to the Surface of Ultrasmall Gold Nanoparticles to Enhance Cell Penetration

Three different alkyne-terminated aggregation-induced emission molecules based on a para-substituted di-thioether were attached to the surface of ultrasmall gold nanoparticles (2 nm) by copper-catalyzed azide–alkyne cycloaddition (click chemistry). They showed a strong fluorescence and were well water-dispersible, in contrast to the dissolved AIE molecules. The AIE-loaded nanoparticles were not cytotoxic and easily penetrated the membrane of HeLa cells, paving the way for an intracellular application of AIE molecules, e.g., for imaging.