The main subject of this thesis is to examine thermo-osmotic flows, which occur on interfaces of non-uniform temperature. Such thermo-osmotic flows are purely non-thermal equilibrium phenomena. Along the non-isothermal interface, specific interaction of a liquid and its solutes with a boundary vary in strength across the interface, according to the local temperature. This boundary can be a solid, a membrane or a phase boundary. The flow is thereby continuously pumping fluid across the interface in direction of the local temperature gradient, resulting in an extended flow pattern in the bulk due to mass conservation. In a system containing particles and heat sources in a liquid under spatial confinement, the thermo-osmotic flow may drive particles in a directed manner, or can lead to collective phenomena. To approach this broad topic of (self-)thermophoresis and collective motion of active particles and quantify the role of the thermo-osmotic flow upon the latter effects, different experiments have been performed: The first experiments aim to quantify the thermo-osmotic flow at a non-isothermal liquid/solid interface for two fundamentally different substrate properties. Further, the bulk flow was investigated for two different systems. The form and spatial extension of this bulk flow pattern depends sensitively on the form of the container and the interface, as well as on the thermo-osmotic flow. The first system is a liquid film confined between two planar glass cover slips. The second case is a Janus particle immobilized on one of the glass slips. In the first case, the non-uniform temperature profile is generated by optical heating of a nanometer sized gold colloid, and in the second case, the heat source is the Janus particle. The bulk flow pattern consists, for the second case, of the flow pattern created by the glass cover slips and the one created by the Janus particle. The following experiments are focusing on the dynamics of mobile self-thermophoretic Janus particles. In particular, their dynamics and the contributions of the thermo-osmotic flow to the interaction of multiple active particles are investigated. To investigate those particles under controlled conditions and examine their interactions at low concentrations for an effectively unlimited amount of time, a real-time feedback algorithm was co-developed to gain control of the motion of multiple active particles simultaneously, called ”photon nudging”. With the help of this method, first experiments have been performed to quantify the dynamics of a Janus particle located close to a heat source.

The creation of complex polymer structures has been one of the major research topics over the last couple of decades. This work deals with the synthesis of (block co-)polymers, the creation of complex and stimuli-responsive aggregates by self-assembly, and the cross-linking of these structures. Also the higher-order self-assembly of the aggregates is investigated. The formation of poly-2-oxazoline based micelles in aqueous solution and their simultaneous functionalization and cross-linking using thiol-yne chemistry is e.g. presented. By introducing pH responsive thiols in the core of the micelles the influence of charged groups in the core of micelles on the entire structure can be studied. The charging of these groups leads to a swelling of the core and a decrease in the local concentration of the corona forming block (poly(2-ethyl-2-oxazoline)). This decrease in concentration yields a shift in the cloud point temperature to higher temperatures for this Type I thermoresponsive polymer. When the swelling of the core is prohibited, e.g. by the introduction of sufficient amounts of salt, this behavior disappears. Similar structures can be prepared using complex coacervate core micelles (C3Ms) built through the interaction of weakly acidic and basic polymer blocks. The advantage of these structures is that two different stabilizing blocks can be incorporated, which allows for more diverse and complex structures and behavior of the micelles. Using block copolymers with either a polyanionic or a polycationic block C3Ms could be created with a corona which contains two different soluble nonionic polymers, which either have a mixed corona or a Janus type corona, depending on the polymers that were chosen. Using NHS and EDC the micelles could easily be cross-linked by the formation of amide bonds in the core of the micelles. The higher-order self-assembly behavior of these core cross-linked complex coacervate core micelles (C5Ms) was studied. Due to the cross-linking the micelles are stabilized towards changes in pH and ionic strength, but polymer chains are also no longer able to rearrange. For C5Ms with a mixed corona likely network structures were formed upon the collapse of the thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm), whereas for Janus type C5Ms well defined spherical aggregates of micelles could be obtained, depending on the pH of the solution. Furthermore it could be shown that Janus micelles can adsorb onto inorganic nanoparticles such as colloidal silica (through a selective interaction between PEO and the silica surface) or gold nanoparticles (by the binding of thiol end-groups). Asymmetric aggregates were also formed using the streptavidin-biotin binding motive. This is achieved by using three out of the four binding sites of streptavidin for the binding of one three-arm star polymer, end-functionalized with biotin groups. A homopolymer with one biotin end-group can be used to occupy the last position. This binding of two different polymers makes it possible to create asymmetric complexes. This phase separation is theoretically independent of the kind of polymer since the structure of the protein is the driving force, not the intrinsic phase separation between polymers. Besides Janus structures also specific cross-linking can be achieved by using other mixing ratios. / In den letzten Jahrzehnten war die Herstellung von komplizierten Polymerstrukturen ein wichtiges Forschungsthema für Polymerchemiker. Diese Arbeit behandelt die Synthese von (Blockco-)Polymere, die Herstellung von komplexen und stimulus-responsiven Aggregaten (Mizellen) durch Selbstorganisation, sowie die Vernetzung dieser Strukturen. Auch die Anordnung dieser Mizellen zu Aggregaten mit höherer Ordnung wurde untersucht. Zum Beispiel wird die Bildung von Poly(2-oxazolin) basierter Mizellen in wässriger Lösung und die gleichzeitige Funktionalisierung und Vernetzung dieser Mizellen mittels Thiol-In-Chemie beschrieben. Durch die Einführung von pH-responsiven Gruppen in den Kern der Mizellen konnte der Einfluss von geladenen Gruppen im Kern auf das gesamte Aggregat untersucht werden. Das Einführen von Ladung führt zum Quellen des Mizellkerns und damit zu einer niedrigeren lokalen Konzentration von wasserlöslichem Poly(2-ethyl-2-oxazolin) (PEtOx). Diese niedrigere Konzentration ergibt eine Verschiebung des Trübungspunkt dieses Typ I thermoresponsiven Polymers zu höheren Temperaturen. Wenn die Ausdehnung des Kerns nicht erfolgt, z.B. in Anwesenheit einer hohen Salzkonzentration, findet dieser Effekt nicht statt. Ähnliche Strukturen können mithilfe von Mizellen mit komplexen Koazervatkern (English: Complex Coacervate Core Micelles, C3Ms) durch die Interaktion zwischen Polymeren mit negativ und positiv geladenen Blöcken hergestellt werden. Der Vorteil dieser Strukturen ist, dass zwei verschiedene stabilisierende Polymerblöcke in einem Aggregat vereint werden können, was zur Bildung einer Vielzahl noch komplizierterer Strukturen und zu mehr Responsivität führen kann. Mithilfe von Blockcopolymeren, bestehend aus jeweils einen polyionischen Block und einem neutralen Block (z.B. PEtOx, PEO oder poly(N-isopropylacrylamid) (PNIPAAm)), konnten C3Ms hergestellt werden, in denen zwei neutrale Polymere vereint wurden. Es konnte gezeigt werden, dass diese Polymere sowohl gemischt als auch phasensepariert vorliegen können (letzteres ergibt Janus Mizellen), abhängig welche Polymere gewählt werden. Durch Vernetzung im Kern konnten die Mizellen stabilisiert und fixiert werden (C5Ms). Die Selbstanordnung dieser vernetzten Mizellen zu größeren Aggregaten wurde untersucht. Wenn eine Lösung mit vernetzten Mizellen über den Trübungspunkt von PNIPAAm erhitzt wurde, bildeten sich Netzwerke aus Mizellen mit einer gemischten Korona, während Janus Mizellen sich zu wohldefinierten Aggregaten höherer Ordnung anordneten. Weiterhin konnte gezeigt werden, dass Janus Mizellen sich auf der Oberfläche von anorganischen Nanopartikeln anlagern können; z.B. durch die selektive Wechselwirkung zwischen PEO und Silica oder durch die Adsorption von Thiolgruppen auf Gold-Nanopartikeln. Asymmetrische Aggregate konnten auch mithilfe des Streptavidin-Biotin Komplexes erhalten werden. Durch das Binden der Biotin-Endgruppen eines dreiarmigen Sternpolymeren an eine Streptavidin-Einheit und anschließende Belegung der verbliebenen Bindungsstelle mit der Biotin-gruppe eines Homopolymers, können sehr spezifisch zwei verschiedene Polymere in einem Janus Aggregat vereint werden. Auch die Vernetzung des Streptavidins kann erzielt werden, indem andere Mischverhältnisse gewählt werden.

Orientador: Carlos Amilcar Parada / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T09:59:35Z (GMT). No. of bitstreams: 1 Vieira_AndreSchwambach_D.pdf: 871138 bytes, checksum: fc1ecaa5a27015a5ae9ed72d9687b540 (MD5) Previous issue date: 2012 / Resumo: A hiperalgesia inflamatória resulta da sensibilização de nociceptores aferentes periféricos induzida por mediadores inflamatórios. A prostaglandina E2 (PGE2) é uma das principais moléculas sinalizadoras envolvidas na hiperalgesia, sendo capaz de agir diretamente em nociceptores, induzindo mudanças nas propriedades de transdução sensorial destas células. A Janus Quinase 2 (JAK2) é uma molécula sinalizadora intracelular geralmente associada ao mecanismo de ação de citocinas, sendo que sua atividade pode ser induzida em nociceptores após uma inflamação periférica. Entretanto, não existem evidencias do envolvimento direto da JAK2 na sensibilização de nociceptores mediada pela PGE2. Assim o objetivo deste trabalho foi de explorar o possível papel da JAK2 na sensibilização mediada pela PGE2. Em neurônios do gânglio da raiz dorsal (DRG) em cultura foi observado que a PGE2 altera o influxo de cálcio induzido pela capsaicina, e a pré-incubação das células com o inibidor seletivo da JAK2, AG490, foi capaz de bloquear este efeito. Adicionalmente, a administração intratecal de AG490 em ratos reduziu a hiperalgesia induzida pela administração subcutânea e local de PGE2 ou carragenina. A administração intratecal de AG490 também bloqueou a ativação da PKCepsilon induzida no DRG L5 ispsilateral após inflamação na pata. Em conclusão o presente trabalho demonstra que a JAK2 expressa no DRG pode possuir um papel na sensibilização de nociceptores induzida por um evento inflamatório periférico. Desta forma a inibição da JAK2 pode ser um novo alvo farmacológico para o controle da hiperalgesia inflamatória / Abstract: Inflammatory hyperalgesia results from the sensitization of peripheral afferent nociceptors by inflammatory mediators. Prostaglandin E2 (PGE2) is one of the major signaling molecules involved in hyperalgesia, being able to act directly on nociceptors, inducing sensitization. The Janus Kinase 2 (JAK2) is an intracellular signaling molecule generally associated with cytokines signaling pathway, and its activity can be increased in nociceptors after peripheral inflammation. However, there are no evidences about the role JAK2 directly plays in PGE2-induced sensitization of nociceptors. Therefore, the aim of the present study was to explore a possible role for JAK2 in PGE2 mediated sensitization. The data of this study showed in cultured dorsal root ganglion (DRG) neurons, that the administration of PGE2 alters capsaicin-induced calcium transients, and the pre-incubation of the cells with the JAK2 selective inhibitor AG490 blocks this effect. In addition, the intrathecal administration of AG490 in rats reduces the hyperalgesia induced by local administration of PGE2 or carrageenan in the hindpaw. AG490 intrathecal administration also blocks PKCepsilon activation in the ipsilateral L5 DRG induced by inflammation of peripheral tissue. In conclusion, the present study indicates that the JAK2 expressed in the DRG may have a role in the sensitization of nociceptors by a peripheral inflammatory event. Moreover, the inhibition of JAK2 may be a possible novel pharmacological target for the control of the inflammatory hyperalgesia / Doutorado / Fisiologia / Doutor em Biologia Funcional e Molecular

Les matériaux polymères appelés communément "Plastiques" sont très présents dans notre vie quotidienne. Leurs propriétés intrinsèques nécessitent souvent d'être améliorées pour répondre aux normes et autres cahiers des charges régissant leur utilisation. Ainsi, deux grandes stratégies sont aujourd'hui utilisées. La première consiste à incorporer des renforts (exemple de la fibre de verre) pour augmenter certaines propriétés mécaniques. La seconde consiste à mélanger deux polymères distincts possédant chacun des caractéristiques spécifiques pour obtenir un matériau combinant les propriétés des deux polymères de base, Il s'agit alors de "compatibilisation". L'objectif de ce travail de thèse est de fabriquer des nanoparticules capables de combiner les notions de renfort et de compatibilisation précédemment évoquées. Pour ce faire, une stratégie de synthèse en miniémulsion reposant sur un phénomène de séparation interne de phase a permis de produire des nanoparticules hybrides asymétriques. Ces dernières sont formées d'un cœur de silice d'environ 50 nanomètres de diamètre dont l'un des hémisphères seulement a été greffé par des chaînes de polystyrène (PS) formant un nodule d'environ 80 nanomètres de diamètre. Ces nanoparticules asymétriques silice/PS ont ensuite été introduites dans un mélange de polystyrène et de polyamide-6 (PS/PA6). La migration des nanoparticules silice/PS à l'interface de ce mélange a été vérifiée par microscopie électronique à balayage (MEB). Les phénomènes mis en jeu dans cette migration ont été étudiés de façon approfondie via une étude modèle. Des nanocomposites PS/PA6 comportant différents taux de charges de nanoparticules asymétriques ont été réalisés pour vérifier l'effet compatibilisant de ces dernières. Ainsi, une nette diminution des tailles des phases dispersées de PA6 a pu être mise en évidence par MEB et par granulométrie à diffraction laser correspondant à un effet émulsifiant. Enfin, des essais rhéologiques à l'état fondu qui finalisent cette étude et ont permis de montrer via l'utilisation d'un modèle de Palierne ajusté, une diminution de la tension interfaciale apparente du mélange liée au taux de charges en nanoparticules silice/PS. / Polymers materials usually named « plastics » are widely present in our daily life. Their intrinsic properties often need to be improved in order to respect regulations, standards and others specifications governing their commercial use. Thus, two main strategies are used. The first one consists in incorporating solid fillers to improve some mechanical properties. The second one is based on the mixing of two polymers with specific characteristics to obtain a new material combining the properties of the two initial polymers used. The main goal of this work is to synthesize nanoparticles able to combine the both strategies presented before. To do this, a protocol of synthesis by miniemulsion based on an intern phase separation process was employed and hybrid asymmetric nanoparticles were obtained. These hybrid asymmetric nanoparticles correspond to a silica core (around 50 nanometers diameter) with only one hemisphere grafted by polystyrene (PS) chains resulting in a PS nodule (around 80 nanometers diameter). Then, these asymmetric silica/PS nanoparticles were incorporated into a polystyrene/polyamide-6 (PS/PA6) blend and their migration to the matrix/nodule interface was highlighted by scanning electron microscope (SEM). Experimental and theoretical investigations were focus on the phenomena involved in this migration. To evaluate the compatibilizing effect of silica/PS nanoparticles, several PS/PA6 nanocomposites with various contents of nanoparticles were prepared. A significant decrease of PA6 nodules size as function of nanoparticles concentration was observed by SEM and diffraction particle size analyzer which prove an emulsifying effect for silica/PS nanoparticles. Finally, the rheological tests at the melted state combined with an adjusted Palierne model method, show a decrease of the apparent interfacial tension of the blend as function of the silica/PS nanoparticles content.

L'objectif de ce travail est d'étudier l'effet thermoélectrique à l'échelle nanométrique des nanostructures chauffées. Dans un premier temps, nous étudions les mécanismes d'autopropulsion thermo-électrophorétique de particules Janus chauffées par laser. Ce mécanisme d'autopropulsion est principalement induit par l'effet Seebeck ou l'effet thermoélectrique. Cet effet provient de la séparation des charges survenues lorsqu'un gradient de température est présent dans la solution d'électrolyte: Une forte absorption du laser par la partie métallisée de la particule génère un gradient de température qui en retour agit sur les espèces ioniques (positive et négative) et les conduits vers les zones chaudes ou les zones froides. Ce mouvement d'ions entraine la création d'un champ électrique dipolaire qui, à proximité de la particule, dépend fortement des propriétés de surface. Ce changement de comportement de ce champ électrique sur une surface isolant ou conductrice n'affecte pas la vitesse de la particule. Dans un second temps, nous étudions les effets d'interactions hydrodynamiques et de la condensation des contre-ions sur la thermophorèse des polymères d'ADN. Comme résultat principal, la mobilité thermophorétique montre, en fonction de la longueur de la chaîne, un comportement non-monotone et se compose de deux contributions induites par les forces conductrices dominantes que sont l'effet Seebeck et le gradient de permittivité. À la fin, nous comparons notre résultat théorique avec une récente expérience sur l'ADN / The aim of this work is to study the nanoscale Seebeck effect at hot nanostructures. At first, we study the thermo-electrophoresis self-propulsion mechanism for a heated metal capped Janus colloid. The self-propulsion mechanism is mainly induced by the electrolyte Seebeck effect or thermoelectric effect. This effect takes its origin from the separation of charges occurring while a temperature gradient is present in a electrolyte solution: A strong absorption of laser light by the metal side of the particle creates a temperature gradient which in turn acts on ion-species (positive and negative) and drives them to the hot or the cold region. This motion of ion results in a dipolar electric field which, close to the particle, depends strongly on the surface properties. The change of behavior of the electric field at the insulating or conducting surface does not affect the velocity of the particle. At second, we study the effect of hydrodynamic interactions and counterion condensation in thermophoresis for DNA polymer. As the main result, the thermophoretic mobility shows, in function of the chain length, a non-monotonuous behavior and consists of two contributions induced by the dominant driving forces which are the thermally induced permittivity-gradient and the electrolyte Seebeck effect. At the end, we compare our theoretical result with recent experiment on single-stranded DNA.

Orientador: Luiz Henrique de Araújo Machado / Resumo: Dermatite atópica (DA) canina é uma enfermidade alergoinflamatória de caráter crônico, da pele e orelha externa, geralmente de cães adultos jovens, induzida por distintos alérgenos. A afecção tem etiopatologia complexa e ainda não totalmente elucidada, dificilmente atingindo cura. Porém, há hoje, várias opções medicamentosas para o seu controle. O oclacitinib faz parte da recente remessa de medicamentos para tratamento e controle do prurido dos cães atópicos, com poucos efeitos colaterais. É um fármaco inibidor de janus quinase, com rápida ação e que age na ligação das citocinas aos receptores JAKs. Este trabalho teve como intuito avaliar a resposta inflamatória da pele de animais atópicos, antes e 30 dias após o tratamento com Oclacitinib comercial (Apoquel®), através da mensuração das interlucinas IL-1, IL-4, IL-6, IL-10, IL-17, IL-31, TNF-, IFN- e filagrina, pela técnica de imuno-histoquímica, além da resposta clinica ao tratamento pela avaliação do CADESI-4 e escore do prurido. Os 10 cães utilizados no estudo são provenientes do atendimento dermatológico do HV da UNESP-Botucatu e clínica particular de Sorocaba-SP. Apenas os escores do CADESI-4, do prurido e da IL-1, citocina inflamatória chave da imunidade inata e na patogênese da DA, apresentaram redução na análise estatística. Concluise que a IL-1 pode ter um papel importante na farmacocinética do oclacitinib e maiores estudos são necessários para confirmar a ação do oclacitinib sobre a produção e ligação da IL-1 aos ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Canine atopic dermatitis (DA) is a chronic inflammatory alergo disease of the skin and external ear, usually of young adult dogs, induced by distinct allergens. The disease has complex and still not fully elucidated etiopatology, hardly reaching cure. However, there are today several drug options for your control. Oclacitinib is part of the recent consignment of medications for treatment and control of the itching of atopic dogs, with few side effects. It is an inhibitor drug of Janus Kinase, with rapid action and acting in the binding of cytokines to jaks receptors. The objective of this work was to evaluate the inflammatory response of the skin of atopic animals before and 30 days after treatment with commercial oclacitinib (Apoquel®), through the measurement of interlukines il-1, IL-4, IL-6, IL-10, IL-17, IL-31, TNF-α, IFN-γ and Filagrin, by immunohistochemistry technique, in addition to clinical response to treatment by evaluation of Cadesi-4 and pruritus score. The 10 dogs used in the study are from the dermatological treatment of HV of UNESP-Botucatu and private Clinic of Sorocaba-SP. Only the scores of Cadesi4, pruritus and IL-1, the key inflammatory cytokine of innate immunity and the pathogenesis of DA, showed a reduction in the statistical analysis. It is concluded that IL-1 may play an important role in the pharmacokinetics of oclacitinib and further studies are needed to confirm the action of oclacitinib on the production and binding of IL-1 to cutaneous receptors... (Complete abstract click electronic access below) / Mestre

We present a fabrication process to create bifunctional microparticles displaying two different proteins have been spatially segregated onto hemispheres. Silica and polystyrene microparticles with 2.0 m, 4.08 m, and 4.74 m diameters are processed with metal deposition to form two chemically distinct and segregated hemispheres. The surface of each hemisphere is then separately derivatized with proteins using different chemical conjugation strategies. These bifunctional Janus particles possess biologically relevant, native conformation proteins attached to a biologically-unreactive and safe substrate. They also display high densities of two types of spatially segregated proteins which may enable a range of capabilities that monofunctional particles cannot, such as improved targeting of drug carriers and bioimaging agents.

A suite of NLFEA programs, VecTor, has been developed at the University of Toronto. However, this software still requires the development of other functions to execute some types of analyses. One of the required functions is the consideration of transient creep strain in the heat transfer analysis. Moreover, there is a strong need to develop a general graphics-based post-processor applicable to VecTor programs. The first objective of this thesis is to develop a function considering the effect of the transient creep strain, because it can have significant influence on the behaviour of concrete under elevated temperatures. The second purpose of this thesis is to construct the new analysis visualization features compatible with entire suite of VecTor programs. As the result, the modified post-processor, JANUS, has had its abilities expanded significantly.

A suite of NLFEA programs, VecTor, has been developed at the University of Toronto. However, this software still requires the development of other functions to execute some types of analyses. One of the required functions is the consideration of transient creep strain in the heat transfer analysis. Moreover, there is a strong need to develop a general graphics-based post-processor applicable to VecTor programs. The first objective of this thesis is to develop a function considering the effect of the transient creep strain, because it can have significant influence on the behaviour of concrete under elevated temperatures. The second purpose of this thesis is to construct the new analysis visualization features compatible with entire suite of VecTor programs. As the result, the modified post-processor, JANUS, has had its abilities expanded significantly.

Patchy particles are patterned particles with at least one well-defined patch that can have highly directional and strongly anisotropic interactions with other particles or surfaces. Multiple theoretical studies point to interesting self-assembly of these particles into superstructures and, as a result, a multitude of possible applications. However, reliable synthetic methods for patchy particles, especially at the sub-micron level, are still a challenge and an active area of research. This work presents a novel synthesis route for making patchy particles at the sub-micron level that involves the use of capillary condensation. Colloidal silica particles of various sizes were synthesized and ordered into closely-packed arrays via evaporative self-assembly. Various chemical agents were capillary condensed into the voids of this assembly which, due to the face-centered cubic structure of the crystallized colloidal silica, produced distinct \patches" on the particle surface. The patches on these particles were successfully functionalized with gold nanoparticles. This method was shown to provide control over the patch size by modifying the silica particle radius, which thermodynamically changes the amount of capillary condensation. The patchy nature of the resultant particles was confirmed using infrared spectroscopy, scanning electron and optical microscopies, energy dispersive x-ray analysis and zeta potential measurements.