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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Dispersed and deposited polyelectrolyte complexes and their interactions to chiral compounds and proteins

Ouyang, Wuye 05 February 2009 (has links) (PDF)
Polyelectrolyte complexation is a rapidly growing field with applications in functional multilayer (PEM) and nanoparticle (PEC) generation, where PEM films are deposited using Layer-by-Layer technique initiated by Decher and PECs are prepared using mixing-centrifugation technique initiated by our group. Its advantages (e.g. easy preparation) result in various applications in aqueous solution, especially in pharmaceutical and biomedical fields. Therefore, the objectives in this study are to explore interesting applications of polyelectrolyte complexation in the field of low molecular chiral compound and high molecular protein binding. Due to the rapidly growing demands for preparing optically pure compounds in the pharmaceutical field, herein, enantiospecific PEM and PEC were prepared using chiral polyelectrolytes (e.g. homo-polypeptide) and their ability of chiral recognition was investigated by ATR-FTIR, UV/Vis etc.. Chiral PEM and PEC showed pronounced enantiospecificity for both small (amino acids, vitamin) and large (protein) chiral compounds. This chiral recognition is performed by a diffusion process of chiral compounds into PEM based on the structures of chiral selector (PEM, PEC) and chiral probes (chiral compounds). However, the influences, e.g. pH value, ionic strength, surface orientation etc., were found to affect significantly the enantiospecificity. Beside planar substrates, porous membranes (e.g. PTFE) were modified using chiral PEM and successfully applied in enantiospecific permeation. Additionally, protein binding properties of PEC particle dispersions or PEC particle films were also studied. Due to the properties of polyelectrolytes used for PEC (e.g. molecular weight, charge density) and proteins (e.g. isoelectric point, size, hydrophobicity), PEC showed different uptake characteristics towards different proteins. Electrostatic and hydrophobic interaction as well as counterion release force were considered as possible driving forces for protein binding.
2

Dispersed and deposited polyelectrolyte complexes and their interactions to chiral compounds and proteins

Ouyang, Wuye 14 January 2009 (has links)
Polyelectrolyte complexation is a rapidly growing field with applications in functional multilayer (PEM) and nanoparticle (PEC) generation, where PEM films are deposited using Layer-by-Layer technique initiated by Decher and PECs are prepared using mixing-centrifugation technique initiated by our group. Its advantages (e.g. easy preparation) result in various applications in aqueous solution, especially in pharmaceutical and biomedical fields. Therefore, the objectives in this study are to explore interesting applications of polyelectrolyte complexation in the field of low molecular chiral compound and high molecular protein binding. Due to the rapidly growing demands for preparing optically pure compounds in the pharmaceutical field, herein, enantiospecific PEM and PEC were prepared using chiral polyelectrolytes (e.g. homo-polypeptide) and their ability of chiral recognition was investigated by ATR-FTIR, UV/Vis etc.. Chiral PEM and PEC showed pronounced enantiospecificity for both small (amino acids, vitamin) and large (protein) chiral compounds. This chiral recognition is performed by a diffusion process of chiral compounds into PEM based on the structures of chiral selector (PEM, PEC) and chiral probes (chiral compounds). However, the influences, e.g. pH value, ionic strength, surface orientation etc., were found to affect significantly the enantiospecificity. Beside planar substrates, porous membranes (e.g. PTFE) were modified using chiral PEM and successfully applied in enantiospecific permeation. Additionally, protein binding properties of PEC particle dispersions or PEC particle films were also studied. Due to the properties of polyelectrolytes used for PEC (e.g. molecular weight, charge density) and proteins (e.g. isoelectric point, size, hydrophobicity), PEC showed different uptake characteristics towards different proteins. Electrostatic and hydrophobic interaction as well as counterion release force were considered as possible driving forces for protein binding.
3

Partielle Konturierung von Dichtschnüren durch das schichtweise Überflechten mit einer Hebelflechtmaschine

Illmann, Stephanie, Berger, Maik, Denninger, Daniel, Meyer, Torsten 06 December 2018 (has links)
Der Beitrag zeigt die wesentlichen Entwicklungsschritte der Anlagentechnik zur Fertigung partiell konturierter Dichtschnüre. Ausgehend von der Zielstellung einer mehrlagig aufgebauten Kontur erfolgte die Modifizierung einer handelsüblichen Hebelflechtmaschine. Im Speziellen betraf dies die Konstruktion der Handhabungseinrichtungen zur Realisierung der notwendigen Abzugsbewegung. Die Basis der Entwicklung war die Analyse der Hebelflechtmaschine zur Identifizierung der geometrischen und kinematischen Randbedingungen. Im Zuge der Erstellung eines kombinierten CAD/MKS-Modells erfolgte zudem die technologische Betrachtung des vorherrschenden Flechtprozesses unter Berücksichtigung der Verlegekinematik und der resultierenden Fadenablage. Der Beitrag zeigt neben den angesprochenen Entwicklungsschritten auch die Ergebnisse der Erprobung der Anlagentechnik. Im Versuchsbetrieb wurden technologische Parameter evaluiert und vorhandenes Verbesserungspotential konsequent aufgedeckt. Anhand der Fertigung von qualitativen Funktionsmustern konnte die Möglichkeit der partiellen Konturierung mittels einer Hebelflechtmaschine bestätigt werden.

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