Las plantas sintetizan reguladores de crecimiento endógenos que influyen de modo esencial en los procesos fisiológicos de los vegetales. Las prácticas agronómicas actuales están orientadas en su mayor parte a la modificación del desarrollo de las plantas mediante el uso de reguladores de crecimiento. Estas prácticas agrícolas se ven facilitadas, en parte, por la gran cantidad de reguladores sintéticos existentes en el mercado que imitan los efectos de las propias hormonas vegetales.El uso abusivo de fitorreguladores hormonales y pesticidas sintéticos ha provocado la aparición de normativas agrícolas que restringen el uso de aquellos compuestos químicos que provocan alteraciones y disfunciones hormonales en loscultivos. Por tanto, es interesante la investigación básica para desarrollar nuevosfitorreguladores que promuevan alteraciones temporales encaminadas a la reducción de los estreses limitantes de la producción y mejoren la sanidad de los cultivos mediante la inducción de defensas endógenas, lo cual permitiría la reducción del uso de hormonas sintéticas y pesticidas. También es interesante estudiar nuevos compuestos menos tóxicos que sean asimilados por el metabolismo de los vegetales y que tengan capacidad para reducir la aparición de podredumbres de origen fúngico.Entre otros compuestos de origen natural con propiedades reguladoras de crecimiento o bioestimulantes se encuentran los ácidos carboxílicos, las aminas y los azúcares modificados. Estos compuestos por su implicación en el metabolismo vegetal no pueden ser considerados como fitohomonas.Existen pocos estudios relativos a las propiedades de los ácidos carboxílicos como reguladores de crecimiento, sin embargo, hay evidencias suficientes como para afirmar que son compuestos con alto potencial regulador y bioestimulante.Concretamente en esta tesis se ha estudiado el efecto causado por combinaciones del éster etílico del ácido adípico, la furfurilamina, la 1,2,3,4 tetra-O-acetil D-glucopiranosa y el adipato de etilo y 1,2,3,4 tetra-O-acetil D-glucopiranosa.Las investigaciones que se han desarrollado en esta tesis han puesto de manifiesto el alto potencial regulador de tres nuevos reguladores del crecimiento vegetal los cuales se han denominado: FGA (furfurilamina + ester etílico del ácido adípico + 1, 2, 3,4 tetra-O-acetil D-glucopiranosa, TOGE-1 (furfurilamina + adipato de etilo y 1,2,3,4 tetra-O-acetil D-clucopiranosa) y TOGE-2 (1,3-diaminopropano + adipato de etilo y 1,2,3,4 tetra-O-acetil D-clucopiranosa). Estos compuestos son capaces de estimular ciertos aspectos del metabolismo vegetal alargando la vida productiva de las plantas de cultivo que han sido ensayadas como por ejemplo cítricos, tomate y pimiento.Como principales éxitos se ha logrado mejorar la respuesta de los cultivos frente a los procesos de senescencia inhibiendo las principales enzimas que desencadenan el decaimiento de las plantas. Otra de las cualidades que se han podido determinar es la capacidad de las nuevas moléculas para mejorar el intercambio gaseoso de las plantas y aumentar el uso eficiente del agua que estas realizan. Este aspecto puso de manifiesto que las plantas sometidas a tratamientos con los nuevos PGRs podrían mejorar las respuestas a cierto tipo de estreses, los cuales afectan sobre todo a la capacidad fotosintética de las plantas. En este sentido, la investigación realizada ha permitido comprobar se puede inducir cierto grado de tolerancia al estreses bióticos y tal vez abióticos en ciertas variedades de tomate que a priori se muestran sensibles.Estudios de interacción planta-patógeno han revelado que estos nuevos PGRs pueden estimular mecanismos de defensa inespecíficos en las plantas, los cuales permitirían inducir cierto grado de resistencia a hongos fitopatógenos. Los estudios realizados con hongos del género Alternaria y Botrytis en tomate y Phytophthora en cítricos y pimiento han mostrado resultados positivos en este sentido.

O tratamento da erosão dental transformou-se no novo desafio do século XXI e a restauração direta com resina composta é uma das opções de tratamento para lesões severas, em que há comprometimento estético e funcional. Dentro desse contexto, novos materiais restauradores têm sido avaliados, como materiais contendo flúor em sua composição. Desta forma, o presente estudo teve como por objetivo avaliar in vitro a resistência de união da resina composta contendo ou não biomaterial S-PRG (Ionômero de Vidro com Superfície Pré-Ativada) à dentina erodida. A dentina oclusal planificada de 30 molares humanos (n=15) teve metade de sua face protegida com verniz ácido resistente (dentina hígida - grupo controle), enquanto na outra metade foi produzida uma lesão de erosão através da ciclagem em ácido cítrico 0,05 M (pH 2,3, 10 minutos, 6x/dia) e solução supersaturada (pH 7,0, 60 minutos entre os ataques ácidos). Em cada substrato, foram testados dois sistemas adesivos (um autocondicionante e outro com condicionamento prévio) e duas resinas compostas - uma com nanopartículas (Z350-3M/ESPE) e uma que contém biomaterial S-PRG(Ionômero de Vidro com Superfície Pré-Ativada) em sua composição (Beautifil II -Shofu Inc.). Foram, então, confeccionados cilindros de resina composta, os quais foram submetidos à avaliação da Resistência de União através do ensaio de microtração, após armazenamento em água por 24 horas. A análise do padrão de fratura foi realizada em microscópio ótico (40x). Os valores obtidos de resistência de união (MPa) foram submetidos aos testes de ANOVA (dois fatores) e de comparações múltiplas de Tukey (p<0,05). De acordo com os resultados, não houve diferença estatisticamente significativa entre a interação substrato e materiais restauradores (p=0.711). No entanto, houve diferença entre os substratos (p<0,001) e os materiais restauradores (p=0,002) avaliados. Quanto à resistência de união, os valores obtidos foram: G1 (47,5 ± 12,2 MPa), G2 (34,1 ± 15,8 MPa), G3(31,0 ± 8,3 MPa) e G4 (15,5 ± 13,6 MPa). Os resultados, revelaram uma diferença estatisticamente significante nos substratos avaliados e materiais restauradores. Dentro dos limites do presente estudo, conclui-se que a resistência de união no substrato erodido é inferior ao substrato hígido e que o sistema adesivo autocondicionante contendo biomaterial S-PRG(Ionômero de Vidro com Superfície Pré-Ativada) resulta em menor resistência de união da resina composta à dentina hígida ou erodida. / The treatment of dental erosion has become the new challenge of the 21st century and direct restoration with composite resin is one of the treatment options for severe injuries, in which there is aesthetic and functional impairment. Within this context, new restorative materials have been introduced containing fluoride in their composition. In this way, the objective of the present in vitro study was to evaluate the bond strength of composite resin containing or not biomaterial (S-PRG- Surface Pre-Reacted Glass ) to the eroded dentine. Planned occlusal dentin of 30 human molars (n = 15) had half of its surface protected with acid resistant varnish (sound dentin - control group), while on the other half an erosion lesion was produced by cycling in 0.05 citric acid M (pH 2.3, 10 minutes, 6x/day) and supersaturated solution (pH 7.0, 60 minutes between acid attacks). On both eroded and non-eroded substrates, two adhesive systems (one self-etching and one with pre-conditioning) and two composite resins (one with nanoparticles (Z350-3M / ESPE) and one containing biomaterial S-PRG(Glass Ionomer with Pre-Activated Surface) (Beautifil II-Shofu Inc.)) were tested. Then, composite resin cylinders were built and, after storage in water for 24 hours, were submitted to shear bond strength evaluation under microtensile bond test. The analysis of the fracture pattern was performed under an optical microscope (40x). The obtained values of shear bond strength (MPa) were submitted to ANOVA (two factors) and Tukey multiple comparisons tests (p<0.05). According to the results, there was no statistically significant difference between substrate interaction and restorative materials (p = 0.711). However, there was a difference between the substrates (p <0.001) and the restorative materials (p = 0.002) evaluated. The values obtained were G1 (47.5 ± 12.2 MPa), G2 (34.1 ± 15.8 MPa), G3 (31.0 ± 8.3 MPa) and G4 (15 , 5 ± 13.6 MPa), with a statistically significant difference in the evaluated substrates and restorative materials. The results, revealed a statistically significant difference in the evaluated substrates and restorative materials. According to the limits of the present study, it was concluded that the bond strength in the eroded substrate is inferior to the sound substrate and that the self-etching adhesive system containing S-PRG(Surface Pre-Reacted Glass) biomaterial results in lower bond strength of the composite resin to the sound or eroded dentin.

O tratamento da erosão dental transformou-se no novo desafio do século XXI e a restauração direta com resina composta é uma das opções de tratamento para lesões severas, em que há comprometimento estético e funcional. Dentro desse contexto, novos materiais restauradores têm sido avaliados, como materiais contendo flúor em sua composição. Desta forma, o presente estudo teve como por objetivo avaliar in vitro a resistência de união da resina composta contendo ou não biomaterial S-PRG (Ionômero de Vidro com Superfície Pré-Ativada) à dentina erodida. A dentina oclusal planificada de 30 molares humanos (n=15) teve metade de sua face protegida com verniz ácido resistente (dentina hígida - grupo controle), enquanto na outra metade foi produzida uma lesão de erosão através da ciclagem em ácido cítrico 0,05 M (pH 2,3, 10 minutos, 6x/dia) e solução supersaturada (pH 7,0, 60 minutos entre os ataques ácidos). Em cada substrato, foram testados dois sistemas adesivos (um autocondicionante e outro com condicionamento prévio) e duas resinas compostas - uma com nanopartículas (Z350-3M/ESPE) e uma que contém biomaterial S-PRG(Ionômero de Vidro com Superfície Pré-Ativada) em sua composição (Beautifil II -Shofu Inc.). Foram, então, confeccionados cilindros de resina composta, os quais foram submetidos à avaliação da Resistência de União através do ensaio de microtração, após armazenamento em água por 24 horas. A análise do padrão de fratura foi realizada em microscópio ótico (40x). Os valores obtidos de resistência de união (MPa) foram submetidos aos testes de ANOVA (dois fatores) e de comparações múltiplas de Tukey (p<0,05). De acordo com os resultados, não houve diferença estatisticamente significativa entre a interação substrato e materiais restauradores (p=0.711). No entanto, houve diferença entre os substratos (p<0,001) e os materiais restauradores (p=0,002) avaliados. Quanto à resistência de união, os valores obtidos foram: G1 (47,5 ± 12,2 MPa), G2 (34,1 ± 15,8 MPa), G3(31,0 ± 8,3 MPa) e G4 (15,5 ± 13,6 MPa). Os resultados, revelaram uma diferença estatisticamente significante nos substratos avaliados e materiais restauradores. Dentro dos limites do presente estudo, conclui-se que a resistência de união no substrato erodido é inferior ao substrato hígido e que o sistema adesivo autocondicionante contendo biomaterial S-PRG(Ionômero de Vidro com Superfície Pré-Ativada) resulta em menor resistência de união da resina composta à dentina hígida ou erodida. / The treatment of dental erosion has become the new challenge of the 21st century and direct restoration with composite resin is one of the treatment options for severe injuries, in which there is aesthetic and functional impairment. Within this context, new restorative materials have been introduced containing fluoride in their composition. In this way, the objective of the present in vitro study was to evaluate the bond strength of composite resin containing or not biomaterial (S-PRG- Surface Pre-Reacted Glass ) to the eroded dentine. Planned occlusal dentin of 30 human molars (n = 15) had half of its surface protected with acid resistant varnish (sound dentin - control group), while on the other half an erosion lesion was produced by cycling in 0.05 citric acid M (pH 2.3, 10 minutes, 6x/day) and supersaturated solution (pH 7.0, 60 minutes between acid attacks). On both eroded and non-eroded substrates, two adhesive systems (one self-etching and one with pre-conditioning) and two composite resins (one with nanoparticles (Z350-3M / ESPE) and one containing biomaterial S-PRG(Glass Ionomer with Pre-Activated Surface) (Beautifil II-Shofu Inc.)) were tested. Then, composite resin cylinders were built and, after storage in water for 24 hours, were submitted to shear bond strength evaluation under microtensile bond test. The analysis of the fracture pattern was performed under an optical microscope (40x). The obtained values of shear bond strength (MPa) were submitted to ANOVA (two factors) and Tukey multiple comparisons tests (p<0.05). According to the results, there was no statistically significant difference between substrate interaction and restorative materials (p = 0.711). However, there was a difference between the substrates (p <0.001) and the restorative materials (p = 0.002) evaluated. The values obtained were G1 (47.5 ± 12.2 MPa), G2 (34.1 ± 15.8 MPa), G3 (31.0 ± 8.3 MPa) and G4 (15 , 5 ± 13.6 MPa), with a statistically significant difference in the evaluated substrates and restorative materials. The results, revealed a statistically significant difference in the evaluated substrates and restorative materials. According to the limits of the present study, it was concluded that the bond strength in the eroded substrate is inferior to the sound substrate and that the self-etching adhesive system containing S-PRG(Surface Pre-Reacted Glass) biomaterial results in lower bond strength of the composite resin to the sound or eroded dentin.

The Vehicle Routing Problem with Time Windows (VRPTW) is an important and computationally hard optimization problem frequently encountered in Scheduling and logistics. The Vehicle Routing Problem (VRP) can be described as the problem of designing the most efficient and economical routes from one depot to a set of customers using a limited number of vehicles. This research addresses the VRPTW under the following additional complicating features that are often encountered in practical problems: 1. Customers have strict time windows for receiving a vehicle, i.e., vehicles are not allowed to arrive at the customer’s location earlier than the lower limit of the specified time window, which is relaxed in previous research work. 2. There is a limited number of loading/unloading docks for dispatching/receiving the vehicles at the depot The main goal of this research is to propose a framework for solving the VRPTW with the constraints stated above by generating near-optimal routes for the vehicles so as to minimize the total traveling distance. First, the proposed framework clusters customers into groups based on their proximity to each other. Second, a Probabilistic Route Generation (PRG) algorithm is applied to each cluster to find the best route for visiting customers by each vehicle; multiple routes per vehicle are generated and each route is associated with a set of feasible dispatching times from the depot. Third, an assignment problem formulation determines the best dispatching time and route for each vehicle that minimizes the total traveling distance. iii The proposed algorithm is tested on a set of benchmark problems that were originally developed by Marius M. Solomon and the results indicate that the algorithm works well with about 1.14% average deviation from the best-known solutions. The benchmark problems are then modified by adjusting some of the customer time window limits, and adding the staggered vehicle dispatching constraint. For demonstration purposes, the proposed clustering and PRG algorithms are then applied to the modified benchmark problems.

<p>Friction is the resistive force that arises when two contacting surfaces move relative to each other. Frictional interactions are important from both engineering and biological perspectives. In this research I focus on the fundamental understanding of friction on polymeric and biological surfaces in aqueous environments. First, I examine the frictional properties of a stimulus-responsive hydrogel, poly-N-isopropylacrylamide (pNIPAAm), to understand how different phase states affect its tribological properties. My measurements indicate that gels in a collapsed conformation at low shear rates, exhibit significantly larger friction than swollen gels. These differences arise from changes in surface roughness, adhesive interactions, and chain entanglements of the gel surfaces associated with the phase transition. Importantly, I show that the changes in friction, triggered by an external stimulus, are reversible. </p><p>Second, I examine details of the boundary lubrication mechanism involved in mediating friction and wear in diarthrodial joints. Specifically, I looked at the constituents of the synovial fluid, lubricin and hyaluronic acid (HA) and examined their interactions on model substrates, (1) to determine the effect of surface chemistry on adsorption using surface plasmon resonance (SPR), and (2) to study normal force interactions between these surfaces using colloidal probe microscopy (CPM). I found that lubricin is highly surface-active, adsorbed strongly onto hydrophobic, hydrophilic and also collagen surfaces. Overall, lubricin develops strong repulsive interactions. This behavior is in contrast to that of HA, which does not adsorb appreciably, nor does it develop significant repulsive interactions. I speculate that in mediating interactions at the cartilage surface, an important role of lubricin is one of providing a protective coating on cartilage surfaces that maintains the contacting surfaces in a sterically repulsive state.</p> / Dissertation