Aptamers are short nucleic acid ligands generated by the process of iterative selection. Nucleic acid counterparts to protein antibodies, aptamers bind their targets with relatively high affinities by assuming characteristic shapes. Highly thermostable, open to manipulations and non-immunogenic, these olignucleotides can be readily adapted to a variety of diagnostic assays and harvested for their therapeutic potential. We have particularly focused on the unique prospects that stem from their localization patterns both in vitro and in vivo. While several assays exist for protein diagnostics, many of these are limited by the amount of target they can detect. To overcome these limitations it might prove effective to couple protein detection with nucleic acid based amplification. The Proximity Ligation Assay (PLA) is an innovative technique that facilitates protein detection on a zeptomolar range by amplifying a tiny signal via the polymerase chain reaction. PLA is based on the concept that two DNA tags when co-localized adjacent to one another on a protein surface and ligated via a connector nucleotide will form a unique amplicon that can detected using real-time PCR and in turn detect the protein. We have adapted PLA to the peptide based detection of Bacillus spores as well as the RNA aptamer based detection of cancer cells. Highly sensitive and specific, nucleic acid based PLA could serve as a promising tool in diagnostics. Aptamers have also been analyzed for their localization patterns in vivo. Using two anti-prostate specific membrane antigen RNA aptamers, we have demonstrated that there is an inherent bias for some circulating oligonucleotides over others based solely on their sequence. This phenomenon has also been explored in cancer models of mice for persistence of specific aptamers over others in tumors for therapy. An in vivo “Stealth” selection scheme has also been designed and executed to hunt for stable and robust aptamer species that are naturally chosen for survival within a mouse system. Generation of such ligands could benefit several therapeutic ventures such as targeted drug delivery past complex vasculature as in the case of the blood:brain barrier. / text

Polymeric fibres influence our everyday life in numerous aspects; the area of applications ranges from industrial to everyday commodities, textile and non-textile. As the global demand for the polymeric fibres increases rapidly, new innovative classes of fibres and the manufacturing processes are sought after. This thesis develops an approach to produce fine cell structure and low void fraction foams, which is then used in the manufacturing of lightweight, biodegradable foam fibres. Poly (lactic) acid-clay nanocomposite have been foamed with nitrogen and drawn to different melt draw ratio to produce foam fibres. The foam fibres are then characterized for crystallinity, Young’s modulus and the yield stress. While the drawability of foam has been demonstrated, the crystallinity as well as the mechanical properties of the foam fibres are not drastically enhanced by drawing, as would be expected. Further drawing processes of the as-spun foam fibres are recommended.

Polymeric fibres influence our everyday life in numerous aspects; the area of applications ranges from industrial to everyday commodities, textile and non-textile. As the global demand for the polymeric fibres increases rapidly, new innovative classes of fibres and the manufacturing processes are sought after. This thesis develops an approach to produce fine cell structure and low void fraction foams, which is then used in the manufacturing of lightweight, biodegradable foam fibres. Poly (lactic) acid-clay nanocomposite have been foamed with nitrogen and drawn to different melt draw ratio to produce foam fibres. The foam fibres are then characterized for crystallinity, Young’s modulus and the yield stress. While the drawability of foam has been demonstrated, the crystallinity as well as the mechanical properties of the foam fibres are not drastically enhanced by drawing, as would be expected. Further drawing processes of the as-spun foam fibres are recommended.

Neste trabalho foi estudado o processo de tenacificação do poli(ácido lático), PLA, através da produção de blenda com terpolímero randômico (etileno/éster acrílico/glicidil metacrilato), EMA-GMA, como modificador de impacto. Três composições foram estudadas, 90/10, 80/20 e 70/30% em massa, as misturas foram homogeneizadas em extrusora dupla-rosca (melt blending) e corpos de prova foram moldados por injeção. A avaliação do comportamento mecânico e da eficiência da tenacificação foi realizada através de ensaios mecânicos de tração (ATSM D638), resistência ao impacto Izod com entalhe (ASTM D256), flexão (ASTM D790) e dureza Shore D (ASTM 2240). A presença de umidade e a temperatura de degradação foram avaliadas por análise termogravimétrica (TGA), as temperaturas de transição vítrea (Tg), fusão cristalina (Tm) e grau de cristalinidade foram avaliadas por calorimetria exploratória diferencial (DSC) e a morfologia foi analisada por meio de micrografias obtidas por microscopia eletrônica de varredura (MEV). Os resultados dos ensaios mecânicos idicaram que todas as blendas possuem valores de tenacidade superiores ao do PLA. Entretanto, as blendas apresentaram como efeito colateral queda em módulo (obtidos por ensaios de resistência a tração e flexão), resistência a tração no ponto de escoamento e dureza, em função do aumento da concentração de EMA-GMA no PLA. Na composição com 20% de EMA-GMA a distribuição da dispersa ao longo da fase matriz está mais homogênea, e a composição com 30% de EMA-GMA resultou em um material super tenaz (com valores de resistência ao impacto Izod com entalhe acima de 500J/m). / In this work poly(lactic acid), PLA, was toughened by addition a thermoplastic elastomer, the random terpolymer (ethylene / acrylic ester / glycidyl methacrylate), EMA-GMA. Three= compositions were prepared: with concentrations of 10, 20 and 30 wt% of EMA-GMA into PLA. The blends were prepared in a twin-screw extruder and molded by injection molding. The samples were systematically characterized by tensile strength, notched Izod impact strength, flexural properties and Shore hardness (using Shore D scale). The presence of moisture and the degradation temperature of PLA were evaluated by thermogravimetric analysis (TGA), the glass transition temperature (Tg), crystalline melting (Tm) and crystallinity index of PLA and of the blend were evaluated by differential scanning calorimetry (DSC) and the blend morphology was analyzed by scanning electron microscopy (SEM). The results showed that all blends presented a dramatic increase in their toughness, when compared to PLA. However, the moduli (obtained by tensile and flexural tests), tensile strength at yield, and hardness decreased when the dispersed phase content increased. In the 80/20 PLA/EMA-GMA blend, the dispersed phase is more homogeneously dispersed within the matrix, and the composition with 30 wt% of EMA-GMA resulted in a super tough material (notched Izod impact strength exceeding 500 J/m).

Submitted by PPG Engenharia e Tecnologia de Materiais (engenharia.pg.materiais@pucrs.br) on 2018-06-25T13:24:34Z No. of bitstreams: 1 Dissserta??o final_Lucas Weber Dias.pdf: 2263503 bytes, checksum: ea9c29b6b538c56ea795610f7bc5a808 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-06-29T13:30:33Z (GMT) No. of bitstreams: 1 Dissserta??o final_Lucas Weber Dias.pdf: 2263503 bytes, checksum: ea9c29b6b538c56ea795610f7bc5a808 (MD5) / Made available in DSpace on 2018-06-29T13:38:08Z (GMT). No. of bitstreams: 1 Dissserta??o final_Lucas Weber Dias.pdf: 2263503 bytes, checksum: ea9c29b6b538c56ea795610f7bc5a808 (MD5) Previous issue date: 2017-08-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The main function of the packaging is to protect the cosmetic from the external environment, avoiding undesirable changes in the product that is contained inside, and thus indispensable for its storage and transpotation. However, its disposal improperly generates a large volume of solid waste, which is directly related to the environmental impact. One of the alternatives to minimize this impact is the use of packages made from biodegradable polymeric films based on polyacrylic acid (PLA), poly (lactic acid ? co- glycolic acid) (PLGA) and polycaprolactone (PCL), blends of theses polymers and incorporation of Zeolites 13x. The thermal, mechanical optical, water vapor barrier and degradation time in saline solution of polymeric systems are evaluated for application as cosmetic packaging. The technique used for the preparation of the polymer films was that of Solvent Casting. The polymer films were characterized by the techniques of UV-Vis Spectrophotometry, Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Scsannig Electron Microscopy (SEM), transparency, water vapor permeability, mechanical assay and absorption spectroscopy atomic. The transmittance results showed that the PCL and PLA blends showed greater blockage to the passage of radiation (190 - 1100nm) and water vapor permeability. The incorporation of PLA or PLGA to the pure PCL resulted in material with batter thermal properties, but more rigid and brittle, not modifying the degradation process until 120 days of incubation. The incorporation of 15% Zeolite 13x into the PCL/PLA blends did not significantly modify the properties evaluated. / As embalagens t?m como principal fun??o, proteger o cosm?tico do meio externo, evitando que ocorram altera??es indesej?veis no produto que est? contido no seu interior, sendo assim indispens?vel para o seu armazenamento e transporte. Por?m, o seu descarte de forma inadequada gera um grande volume de res?duos s?lidos, que est? diretamente relacionado com o impacto ambiental. Uma das alternativas para minimizar este impacto ? a utiliza??o de embalagens confeccionadas a partir de pol?meros biodegrad?veis. Desta maneira, o presente trabalho tem como objetivo a prepara??o e caracteriza??o de filmes polim?ricos biodegrad?veis baseados em Poli ? ?cido l?ctico (PLA), Poli (?cido l?ctico ? co- ?cido glic?lico) (PLGA) e Policaprolactona (PCL), blendas destes pol?meros e incorpora??o de Ze?litas 13x. S?o avaliadas as propriedades t?rmicas, mec?nicas, ?pticas, de barreira a vapor de ?gua e o tempo de degrada??o em solu??o salina dos sistemas polim?ricos, visando aplica??o como embalagem para cosm?ticos. A t?cnica utilizada para a prepara??o dos filmes polim?ricos foi a de Solvent Casting. Os filmes polim?ricos foram caracterizados pelas t?cnicas de Espectrofotometria UV-Vis, Calorimetria Explorat?ria Diferencial (DSC), An?lise Termogravim?trica (TGA), Microscopia Eletr?nica de Varredura (MEV-FEG), transpar?ncia, permeabilidade a vapor de ?gua, ensaio mec?nico e Espectroscopia de absor??o at?mica. Os resultados de transmit?ncia mostraram que a blenda de PCL e PLA apresentou maior bloqueio ? passagem de radia??o (190 nm ? 1100 nm) e ? permeabilidade de vapor de ?gua. A incorpora??o de PLA ou PLGA ao PCL puro resultou num material com melhores propriedades t?rmicas, por?m mais r?gido e quebradi?o, n?o modificando o processo de degrada??o at? 120 dias de incuba??o. A incorpora??o de 15% Ze?lita 13x ? blenda de PCL/PLA n?o modificou significativamente as propriedades avaliadas.

Current plastics are mostly derived from petrochemical sources, as it is a finite resource renewable replacements are sought after. Polymers derived from cyclic esters such as; lactide, valerolactone and caprolactone are of interest. An industrially viable method of producing stereocontrolled polylactide (PLA) from rac-lactide is desired. Previous work on poly(cyclic esters) is overviewed in chapter 1 with an emphasis upon PLA. Chapter 2 reports the coordination of Ti(OiPr)4 to homo/piperazine bridged bis(phenol) (salan) ligands. Under ambient conditions bimetallic structures were produced and a steric dependent equilibrium system is discussed. Forcing conditions resulted in monometallic homopiperazine salan complexes. Their application for the ring-opening-polymerisation (ROP) of rac-lactide is investigated. Homo/piperazine salan titanium catecholates were synthesised and their cytotoxicity investigated by collaborators. Chapter 3 details the synthesis of monometallic homopiperazine salan zirconium/hafnium isopropoxide complexes. Their utility for the ROP of rac-lactide in solution and solvent free systems are discussed. Bimetallic or tetrametallic solid state structures from attempts to coordinate Zr(IV)/Hf(IV) metals to piperazine salan ligands are also discussed. Chapter 4 discusses the complexation of AlMe3 with homopiperazine salan ligands. The resulting monometallic complexes were inactive for the ROP of lactide. Benzyl alcohol derivatives were synthesised and trialled for solvent free ROP of rac-lactide, δ-valerolactone, ε-caprolactone. Co-polymerisations were investigated and a tri-block polymer of poly(ε-caprolactone/δ-valerolactone/rac-lactide) was prepared. Chapter 5, trans-1,4-DACH salen ligands were synthesised and investigated as ligands with Al(III), Ti(IV), Zr(IV), and Zn(II) metal centres. Bimetallic Al(III) and Ti(IV) structures were characterised and trialled for the ROP of rac-lactide. Isotactic PLA was reported for aluminium complexes, dependent upon phenoxy substituents, and these polymerisations were shown to be immortal in nature. Chapter 6 details the synthesis of trans-1,2-DACH salalen ligands which were complexed to AlMe3, these initiators were investigated for the solution ROP of rac-lactide. The further synthesis of benzyloxy derivatives is also reported and they were utilised for solution and solvent free polymerisations of rac-lactide. The initiator’s behaviour is discussed with respect to varying amine and imine groups.

Orientador: Everaldo Carlos Venâncio. / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós Graduação em Nanociências e Materiais Avançados, 2011.

Im Mittelpunkt dieser Studie steht die Beziehung zwischen Politik und Medien, welche bereits zu vielfältigen Untersuchungen angeregt hat1. Der diskutierte Strukturwandel der politischen Kommunikation und der Öffentlichkeit dient auch hier als Grundhypothese zur Diskussion über die Kommunikation der Regierung mit den Medien. Zentral sind dabei Fragen zur politischen Regierungskommunikation2 nach außen, die sich bezüglich der veränderten Konstellation in Entscheidungsprozessen der Großen Koalition stellen. Diese Konstellation zeichnet sich dadurch aus, dass die Union und SPD als politische Hauptgegner zusammenarbeiten müssen und eine funktionsfähige Regierungsarbeit zu leisten haben. Dabei handelt es sich um zunehmend komplexer werdende Entscheidungsfelder, die entsprechend kommuniziert und legitimiert werden müssen, um dem Repräsentativmodell des Regierungssystems gerecht zu werden. Wie sich die Regierungskommunikation der Bundesregierung verändert hat und, ob Veränderungen feststellbar sind, ist das Hauptanliegen dieser Arbeit. Wie und ob sich die Regierungskommunikation gewandelt hat, wird vor dem Hintergrund der Erfordernisse der »Medien- und Informationsgesellschaft« und ihrer theoretischen Grundlagen analysiert. Folgerichtig ist die Leitfrage der vorliegenden Arbeit: »Welche Veränderungen in der Außenkommunikation von Rot-Grün zu Schwarz-Rot haben stattgefunden?« Die Bedeutung dieser Fragestellung für die politikwissenschaftliche Forschung im Bereich politischer Kommunikation ergibt sich erstens aus der Frage nach den Kanälen der Vermittlung politischer Inhalte und zweitens aus den Rollen, die die genuin politischen Akteure und politischen Sprecher als ihre Berater und Vermittler gegenüber Journalisten einnehmen3. Der Forschungsstand zur Thematik der Regierungskommunikation indes ist bislang einigermaßen überschaubar (Kamps/Nieland 2006a; Köhler/Schuster 2006; Jun 2004; Ders. 2007a; Pfetsch 2003a; Dies. 2003b; Tenscher 2003). Es gibt kein umfassendes Werk, das sich eingehend ausschließlich mit Regierungskommunikation beschäftigt. Diese Untersuchung wird als Versuch gesehen, die Veränderungen im Bezug auf Regierungskommunikation als Kommunikation über Regierung in einer postmodernen Mediengesellschaft, in den spezifischen Akteursfeldern zu erhellen. Die Leitfrage stützt sich auf die parteipolitische Zusammensetzung der Großen Koalition und die Kommunikation der Regierungsparteien nach der Regierungsbildung. Hiervon ausgehend wird die These aufgestellt, dass Veränderungen zwar stattgefunden haben und immer noch stattfinden, deren Auswirkungen auf Regierungskommunikation aber nicht so gravierend sind, als dass von einer grundsätzlichen Modifikation der Regierungskommunikation gesprochen werden kann. Es sind eher Anpassungsprozesse, bedingt durch die zunehmende Relevanz elektronischer Medien, aber vor allem Anpassungsprozesse, die ihren Ursprung in gesamtgesellschaftlichen Umwälzungen haben, an denen sich zwangsläufig auch Regierungskommunikation orientieren muss, will sie das Bestehen einer Regierung kommunikativ begleiten und so legitimieren. Es scheint gleichzeitig zu derartigen Transformationsprozessen eine Kontinuität des operativen Teils der Regierungskommunikation zu geben, zu dem ein vorsichtigerer Umgang mit Inszenierungen der Persönlichkeit von Spitzenpolitikern (sog. »Personalisierung«; siehe 3.4) und einer Inszenierung der Inszenierung als Metakommunikation über politische Kommunikation gehört.

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Sustainable polymeric materials put emphasis on mastering the whole life-cycle of polymeric materials. This includes the choice of raw materials, selection of synthesis and processing, environmental impact during long-term use followed by detailed knowledge about recycling and waste management.  Within this large efforts are put in the design and development of new biocomposites using renewable fibres instead of inert ones. The thesis deals with surface modifications of agricultural fibres and the design of biocomposites with optimal long-term properties balancing the potential risk for biodegradation.  The first part of this thesis involved surface modifications of oil palm fibres and production of biocomposites with PP as matrix. The chemical surface modifications of oil palm fibres explored propionylation, PPgMA grafting via solution modification and reactive blending and vinyltrimethoxy silanization as methods. All modified fibre/PP biocomposites showed improvements in the mechanical properties followed also by an improvement of water resistance. In comparison with unmodificed fibres/PP matrix the highest water resistance after the surface modifications of oil palm fibres were observed for silanization followed by PPgMA modified,  PPgMA blending and  propionylation. The second part aimed at producing fully biodegradable biocomposites and analysing the resulting properties with respect to potential risk for biodegradation. Sisal fibres were incorporated in PLA and PHBV and the resulting risk for biodegradation using a fungus, Aspergillus niger, monitored. Neat PLA and PHBV were compared with the corresponding biocomposites and already without fibres both polymers were notably biodegraded by Aspergillus niger. The degree of biodegradation of PLA and PHBV matrices was related to the extent of the growth on the material surfaces. Adding sisal fibres gave a substantial increase in the growth on the surfaces of the biocomposites. Correlating the type of surface modification of sisal fibres with degree of biodegradation, it was demonstrated that all chemically modified sisal/PLA biocomposites were less biodegraded than unmodified sisal biocomposites.  Propionylated sisal/PLA demonstrated the best resistance to biodegradation of all biocomposites while sisal/CA/PLA demonstrated high level of biodegradation after severe invasion by Aspergillus niger. In general, the biodegradation correlated strongly with the degree of water absorption and surface modifications that increase the hydrophobicity is a route to improve the resistance to biodegradation. Designing new biocomposites using renewable fibres and non-renewable and renewable matrices involve the balancing of the increase in mechanical properties, after improved adhesion between fibres and the polymer matrix, with the potential risk for biodegradation. / <p>QC 20130325</p>