26 resultados para Surface modification


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Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

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The work presented in this thesis was developed in collaboration with a Portuguese company, BeyonDevices, devoted to pharmaceutical packaging, medical technology and device industry. Specifically, the composition impact and surface modification of two polymeric medical devices from the company were studied: inhalers and vaginal applicators. The polyethylene-based vaginal applicator was modified using supercritical fluid technology to acquire self-cleaning properties and prevent the transport of bacteria and yeasts to vaginal flora. For that, in-situ polymerization of 2-substituted oxazolines was performed within the polyethylene matrix using supercritical carbon dioxide. The cationic ring-opening polymerization process was followed by end-capping with N,N-dimethyldodecylamine. Furthermore, for the same propose, the polyethylene matrix was impregnated with lavender oil in supercritical medium. The obtained materials were characterized physical and morphologically and the antimicrobial activity against bacteria and yeasts was accessed. Materials modified using 2-substituted oxazolines showed an effective killing ability for all the tested microorganisms, while the materials modified with lavender oil did not show antimicrobial activity. Only materials modified with oligo(2-ethyl-2-oxazoline) maintain the activity during the long term stability. Furthermore, the cytotoxicity of the materials was tested, confirming their biocompatibilty. Regarding the inhaler, its surface was modified in order to improve powder flowability and consequently, to reduce powder retention in the inhaler´s nozzle. New dry powder inhalers (DPIs), with different needle’s diameters, were evaluated in terms of internal resistance and uniformity of the emitted dose. It was observed that they present a mean resistance of 0.06 cmH2O0.5/(L/min) and the maximum emitted dose obtained was 68.9% for the inhaler with higher needle´s diameter (2 mm). Thus, this inhaler was used as a test and modified by the coating with a commonly-used force control agent, magnesium stearate, dried with supercritical carbon dioxide (scCO2) and the uniformity of delivered dose tests were repeated. The modified inhaler showed an increase in emitted dose from 68.9% to 71.3% for lactose and from 30.0% to 33.7% for Foradil.

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Dissertação apresentada à Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Bioenergia

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Dissertação para Obtenção de Grau de Mestre em Engenharia Química e Bioquímica

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The Aquitaine Basin (southwestern France) is known since long ago for its richness in marine miocene deposits of various facies. A few stratotypes concerning this period have been described in the investigated area. The stratigraphical framework has been recently revised and the study of new exposures completes our knowledge on these levels. In the present work, the authors produce a biostratigraphical distribution of about 160 species (larger and smaller foraminifera), found in the surface exposures of Aquitaine, from the topmost Oligocene (Chattian) through to Middle Miocene (including Serravallian). As a rule, the common species without significant ranges have not bcen mentioned. The microfaunas of several exposures have been thoroughly revised, which has allowed to precise the distribution of many species and induced a few modifications of the results previously produced. Synonymy problems and new taxonomical revisions have been taken into account. Of course, this work will be probably submitted to some changes according to new research on the already known exposures or other more recently discovered.

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The Aquitaine Basin (southwestem France) is known since long ago for its richness in marine miocene deposits ofvarious facies. A few stratotypes concerning this period have bccn described in the investigated area. The stratigraphical framework has becn recently revised and the study of new exposures completes our knowledge on these levels. In the present work, the authors produce a biostratigraphical distribution of about 160 species (Iarger and smaller foraminifera), found in the surface exposures of Aquitaine, from the topmost Oligocene (Chattian) through to Middle Miocene (including Serravallian). As a rule, the common species without significant ranges have not bcen mentioned. The microfaunas of several exposures have been thoroughly revised, which has allowcd to precise the distribution of many species and induced a few modifications of the results previously produced. Synonymy problems and new taxonomical revisions have been taken into account. Of course, this work will be probably submitted to some changes according to new research on the already known exposures or other more recently discovered.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Mecânica

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This dissertation is presented to obtain a Master degree in Structural and Functional Biochemistry

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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This work aimed at the development of a (bio)polymeric monolithic support for biopharmaceuticals purification and/or capture. For that, it was assured that functional groups on its surface were ready to be involved in a plethora of chemical reactions for incorporation of the desired and most suitable ligand. Using cryogelation as preparation method a screening on multiple combinations of materials was performed in order to create a potentially efficient support with the minimal footprint, i.e. a monolithic support with reasonable mechanical properties, highly permeable, biocompatible, ready to use, with gravitational performance and minimal unspecific interactions towards the target molecules, but also biodegradable and produced from renewable materials. For the pre-selection all monoliths were characterized physico-chemically and morphologically; one agarose-based and two chitosan-based monoliths were then subjected to further characterizations before and after their modification with magnetic nanoparticles. These three specimens were finally tested towards adenovirus and the recovery reached 84% for the chitosan-GMA plain monolith prepared at -80°C. Monoliths based on chitosan and PVA were prepared in the presence and absence of magnetic particles, and tested for the isolation of GFP directly from crude cellular extracts. The affinity ligand A4C7 previously selected for GFP purification was synthesized on the monolith. The results indicated that the solid-phase synthesis of the ligand directly onto the monolith might require optimization and that the large pores of the monoliths are unsuitable for the purification of small proteins, such as GFP.

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Dissertação para obtenção do Grau de Mestre em Engenharia Informática

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In the context of this dissertation several studies were developed resulting in submission and publication “Evaluation of mechanical soft-abrasive blasting and chemical cleaning methods on alkyd-paint graffiti made on calcareous stones” to Journal of Cultural Heritage. (http://dx.doi.org/10.101 /j.culher.2014.10.004)