Three-dimensional spheroid arrays represent in vivo activity better than conventional 2D cell culturing. A high-throughput microfluidic chip may be capable of depositing cells into spheroid arrays, but it is difficult to regulate the path of individual cells for deposition. Droplets that encapsulate cells may aid in facilitating cell delivery and deposition in the return bend of a microfluidic chip. In this study, a low-cost method for fabricating polymer-cast microfluidic chips has been developed for rapid device prototyping. Computational fluid dynamic (CFD) simulations were conducted to quantify how a change in geometry or fluid properties affects the dynamics of a droplet. These simulations have shown that the deformation, velocity, and trajectory of a droplet are altered when varying the geometry and fluid properties of a multiphase microfluidic system. This quantitative data will be beneficial for the future design of a microfluidic chip for cell deposition into 3D spheroid arrays.

The diploma thesis is processed as an experimental verification of properties of cyanoacrylate adhesives Loctite and SikaLock. The experiment compares properties of mentioned adhesives on ten different materials. These Materials were glued to the overlap joint. After bonding one part of samples were left usual conditions and the second part was put into the kataplasma, where the samples were exposed extreme conditions (high wetness and temperature). The next step was a test for shear stress. Measured values were recorded in graphs, for each pasted material.

Les matériaux composites sont depuis plusieurs décennies un domaine d’innovation dans le contexte de l’allégement des structures. Néanmoins, ils subsistent encore certains points d’amélioration concernant l’assemblage de ceux-ci entre eux ou sur des pièces métalliques. Le collage dit « structural » est alors une technologie incontournable pour l’assemblage de structure multi-matériaux. L’intégration du collage dans le processus de développement et de dimensionnement des structures requiert l’utilisation de modèles numériques adaptés ainsi qu’une approche de caractérisation fiable. De plus, dans le domaine du crash (code explicite), le modèle doit être compatible avec les contraintes de temps de calcul. Ces travaux de thèse proposent de définir une démarche de caractérisation et de modélisation des assemblages par collage soumis à des sollicitations dynamiques. L’objectif final est de proposer un modèle capable de simuler des structures sous sollicitations de types crash. Pour cela, un modèle phénoménologique (modèle à l’échelle mésoscopique) est caractérisé à l’aide d’essai de type bulk. Ce modèle permet une description fine du champ mécanique au sein d’un assemblage. Ce modèle combiné avec des essais réalisés sur un dispositif de type Arcan spécialement adapté pour des sollicitations dynamiques permet une identification d’un critère de rupture intrinsèque. À l’aide de ce modèle et du critère de rupture, un élément cohésif (modèle à l’échelle macroscopique) compatible avec les contraintes de temps de calcul est identifié. Finalement, ce modèle est validé par des essais dynamiques de sous-structure multi-matériaux. / Since few decades, composite material is an innovative field for the reduction of structure weight. However, assemblies of composite together or with metallic part are still a challenging point. Structural bonding is an unavoidable technology for the assemblies of multi-materials structures. Within the development and dimensioning procedure, the use of bonding requires the definition of numerical models and characterization methods. Furthermore, in crashworthiness (explicit code), models must be in agreement of time calculation limitations. The present work propose to define a modelling and characterisation approach for bonding assemblies under dynamic loading. The final aim is to provide a model able to modelling multi-materials structure under crash loading. For it, a characterisation of a phenomenological model (mesoscopic scale) is proposed. This model allow a fine description of the mechanical field in the bonded joint. With test carried out with an Arcan test device specially developed for dynamic loading, the mesoscopic model is used for the identification of an intrinsic failure criteria. Using mesoscopic model and the intrinsic failure criteria, a cohesive model (macroscopic model) in agreement of time calculation limitations is identified. Finally, this model is validated through dynamic tests on multi-materials substructures.

Orientador: Gimol Benzaquen Perosa / Resumo: Há evidências na literatura de que a permanência dos prematuros em incubadora, com o propósito de garantir sua sobrevida, pode gerar um impacto negativo para o vínculo mãe/filho. Na maioria das vezes a criança está sedada e as mães impossibilitadas do contato tátil e de oferecer cuidados. Há vários estudos de como as mães vivenciam essa situação, mas poucos centram-se no papel da voz materna que, nessas condições, é uma via disponível para o estabelecimento do vínculo com o bebê, fundamental para sua constituição subjetiva. Este estudo teve por objetivo analisar o conteúdo da fala e a voz das mães frente a seu parto e a seu filho prematuro, pacientes de incubadora. Os médicos responsáveis pelo pelos leitos das crianças da pesquisa também foram entrevistados com o intuito de avaliar seu papel na forma como a mãe subjetiva a criança neste contexto. Em até sete dias após a internação da criança na Unidade de Terapia Intensiva neonatal (UTIN), foi realizada uma primeira entrevista, aberta, com mães de prematuros que permaneciam na incubadora. Uma segunda entrevista ocorreu após a alta da incubadora. Os médicos responsáveis pelo leito da criança também foram entrevistados, afim de encontrar possíveis relações do discurso médico com o discurso materno. Observou-se, também, como e o que as mães diziam aos bebês e seus comportamentos quando elas falavam com eles. Os dados foram analisados qualitativamente, à luz da teoria psicanalítica. A característica mais presente nos relatos foi ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: There is evidence in the literature of the negative impact that keeping premature babies in incubators - to ensure they will survive - can cause to mother-child bonding. Most of the times, the child is sedated and the mother cannot offer tactile contact or care. There are many studies on how mothers manage this situation, but only a few focus on the mother’s voice, that is, in these conditions, an available way to bonding with the baby, which is essential to their subjective constitution. The present study’s aim was to understand mothers’ perception of premature delivery, their role during the child’s stay in the incubator and their interaction with the babies. In up to seven days after the internment in the Neonatal Intensive Care Unit (NICU), an open interview with mothers of newborns in incubators was held. A second interview took place after the discharge from the incubator. The doctors responsible for each crib were also interviewed in an attempt to find possible correlations between the medical and the maternal speech. It was also observed what mothers told their babies, how they did it and their behavior while talking to them. A qualitative analysis of data was done according to the psychoanalysis theory. The need to rebuild minutely the premature newborn story was the most common feature in the mothers’ report. Facing the perplexity of the situation, mothers tried to connect moments by recalling details, organizing their story and trying to fill up the emptiness and t... (Complete abstract click electronic access below) / Mestre

Hartree-Fock, Moller-Plesset, and density functional theory calculations have been carried out using 6-31+G(d), 6-31+G(d,p) and 6-31++G(d,p) basis sets to study the properties of low-barrier or short-strong hydrogen bonds (SSHB) and their potential role in enzyme-catalyzed reactions that involve proton abstraction from a weak carbon-acid by a weak base. Formic acid/formate anion, enol/enolate and other complexes have been chosen to simulate a SSHB system. These complexes have been calculated to form very short, very short hydrogen bonds with a very low barrier for proton transfer from the donor to the acceptor. Two important environmental factors including small amount of solvent molecules that could possibly exist at the active site of an enzyme and the polarity around the active site were simulated to study their energetic and geometrical influences to a SSHB. It was found that microsolvation that improves the matching of pK as of the hydrogen bond donor and acceptor involved in the SSHB will always increase the interaction of the hydrogen bond; microsolvation that disrupts the matching of pKas, on the other hand, will lead to a weaker SSHB. Polarity surrounding the SSHB, simulated by SCRF-SCIPCM model, can significantly reduce the strength and stability of a SSHB. The residual strength of a SSHB is about 10--11 kcal/mol that is still significantly stable compared with a traditional weak hydrogen bond that is only about 3--5 kcal/mol in any cases. These results indicate that SSHB can exist under polar environment. Possible reaction intermediates and transition states for the reaction catalyzed by ketosteroid isomerase were simulated to study the stabilizing effect of a SSHB on intermediates and transition states. It was found that at least one SSHB is formed in each of the simulated intermediate-catalyst complexes, strongly supporting the LBHB mechanism proposed by Cleland and Kreevoy. Computational results on the activation energy for catalyzed and uncatalyzed model reactions shows that strong hydrogen bonding between catalyst and the substrate at the transition state can significantly reduce the activation energy. This implies that LBHBs are possibly playing a crucial role in enzyme catalysis by supplying significant stabilizing energy to the reaction transition state.

In many areas of engineering industries there are necessary to bond steel, where traditional bonding processes such as welding and brazing are neither efficient enough nor possible. Alternative technique is transient liquid phase bonding (TLPB). In this study, carbon steel (IRAM 1010/1040) have been welded using transient liquid phase bonding method with Fe-B amorphous as filling material. The joints were performed by induction heating with argon flux, set pressure and different temperature and bonding times. The welded bars were then analysed using optical and scanning electronic microscopy (SEM).   The bars with good microstructures and optimal parameters were then tested with galvanostatic corrosion test against each other and non-welded bar to study the corrosion behaviours.  The study shows that the IRAM 1010 steel corroded slightly faster than the IRAM 1040 but comparing with the non-welded bars, still consider having good corrosion resistance.   In this study, TLP bonding shows to be a relevant method to weld low and medium carbon steel, regarding to the microstructure of the weld, corrosion behaviour, bonding time and temperature.

Models of chemical bonding are essential for contemporary chemistry. Even the explosive development of the computational resources including, both hardware and software, cannot eliminate necessity of compact, intuitive, and efficient methods of representing chemically relevant information. The Lewis model of chemical bonding, which was proposed eleven years before the formulation of quantum theory and preserves its pivotal role in chemical education and research for more than ninety years, is a vivid example of such a tool. As chemistry shifts to the nanoscale, it is becoming obvious that a certain shift of the paradigms of chemical bonding is inescapable. For example, none of the currently available models of chemical bonding can correctly predict structures and properties of sub-nano and nanoclusters. Clusters of main-group elements and transition metals are of major interest for nanotechnology with potential applications including catalysis, hydrogen storage, molecular conductors, drug development, nanodevices, etc. Thus, the goals of this dissertation were three-fold. Firstly, the dissertation introduces a novel approach to the description of chemical bonding and the algorithm of the software performing analysis of chemical bonding, which is called Adaptive Natural Density Partitioning. Secondly, the dissertation presents a series of studies of main-group element and transition-metal clusters in molecular beams, including obtaining their photoelectron spectra, establishing their structures, analyzing chemical bonding, and developing generalized model of chemical bonding. Thirdly, the dissertation clarifies and develops certain methodological aspects of the quantum chemical computations dealing with clusters. This includes appraisal of the performance of several computational methods based on the Density Functional Theory and the development of global optimization software based on the Particle Swarm Optimization algorithm.

Proteins are made of vast chains of amino acids that twist and fold into intricate designs. These structures are held in place by networks of noncovalent interactions. One of these, the hydrogen bond, forms bridges between adjacent pieces of the protein chain and is one of the most important contributors to the shape and stability of proteins. Hydrogen bonds come in all shapes and sizes and a full understanding of these not only aids in our understanding of proteins in general but can bridge the gap to finding cures to many protein-related diseases, such as sickle-cell anemia. The primary aim of this thesis is to discover if a specific type of hydrogen bond, the N-H···N bond, occurs within proteins and if so, if it contributes to the structure and stability of proteins.

Introduction: One factor that contributes greatly to the lower face appearance and orthodontists have the ability to affect is lip profile. Clinical assessment of the lip profile is an important element in the decision of orthodontic treatment planning and in the evaluation of treatment progress and outcome. Three known factors influence the lip profile; the lip thickness, the underlying bone, and the tooth position. The positions and inclinations of the anterior teeth can affect the lip position, but it is unclear whether orthodontic brackets bonded to the labial surface of anterior teeth move the lip position and thereafter change the lip profile. Therefore, it is necessary to determine if orthodontic brackets bonded to the labial surface of the anterior dentition have any impact on lip profile. Objective: The objective of this project was to determine the effect that bonded brackets have on lip profile utilizing a standardized lateral photographic cephalogram analysis during the bonding and debonding stages. Methods: To determine the effect of bonded brackets on lip profile, digital photographic cephalometry was used. The patient was seated against a white backdrop in the standardized natural head position. Photographs were taken 5 feet from the patient, centered and level with the middle of the tragus of the right ear and were digitally analyzed using Dolphin Imaging software. Photos were acquired from 4 time points: before bonding (BT0) and after bonding (BT1) for the bonding group, and before debonding (DT0) and after debonding (DT1) for the debonding group. Upper and lower lip to E-plane, subnasale and lower lip to H-Line, superior sulcus depth, nasolabial angle, Z angle, upper and lower lip protrusion, and upper and lower lip to S-line were measured and analyzed statistically. The correlation of tooth angulation, lip thickness (determined using existing cephalometric radiographs), and bracket thickness on effect of lip position was also determined. Results: There are significant differences in all measurements of the lip profile, except superior sulcus depth and nasolabial angle, between BT0 and BT1 at the bonding stage. In the bonding stage, change in Z angle was correlated to initial lower lip thickness and change in upper lip protrusion was correlated to the initial upper lip thickness at the vermilion boarder and upper incisor bracket thickness. There was no significant difference noted between DT0 and DT1 at the debonding stage. Conclusion: Brackets have a significant effect on lip profile when bonding labial orthodontic brackets. Brackets have no significant effect on lip profile when debonding brackets. Therefore, a direct clinical assessment of lip profile before debonding is valid with no interference imposed by bonded orthodontic brackets.

Indiana University-Purdue University Indianapolis (IUPUI) / This investigation examined the relationships among light cured glass ionomer liner, light cured glass ionomer base, and composite resin material in the reattachment of fractured anterior tooth fragments. Seventy-five bovine incisor teeth were fractured and luted back together with three different materials (Universal Bonding Agent/TPH Composite Resin; VariGlass VLC Liner; VariGlass VLC Base, LD Caulk Div Dentsply Int Inc, Milford, DE) of equal number. The reattached fragments were subjected to thermocycling with a 40° C differential and then were loaded until the force required to detach the fragment was reached. The mean dislodgment strengths were 36.8 (± 25.6)kg for the composite resin, 36.4 (± 26.7)kg for the glass ionomer base, and 31.4 (± 29.S)kg for the glass ionomer liner. Analysis of variance demonstrated no significant difference between the three groups at p≤0.05. Also examined was the type of fracture after reattachment. Of the sixty-five teeth that were studied microscopically, 84.6 percent of the fractures were cohesive in nature, thus a breakdown occurred within the material itself.