In one of the non-destructive testing techniques, Lamb waves, because of its ability to propagate a long distance and being hard to attenuate, can detect a wide range of area. However, due to its multimodal and dispersive characteristics, identifying the signals of defects during the test is often difficult. Time reversal method, a self-focusing technique, can offset the dispersion of Lamb waves and effectively focus on the spatial and temporal domain. This study applies the finite element method to stimulate the propagation of Lamb waves on an aluminum plate, selecting four sets of frequency-thickness products and two excitation types to excite the single-mode or multimode Lamb waves. This study aims to discuss the effects of modal and dispersion on the focus of the time reversal methods. The results show that 2 MHz-mm and in-plane excitation can produce numerous, more dispersive modals with the best focus effect. If we applied the time reversal method to testing the defects of Lamb waves, and the defects are circular and longitudinal notches, then, according to the results, the reflection signal amplitude of the circular defects can be highly increased. According to the test results of small-sized notches, the time reversal method cannot effectively improve the detecting ability of this defect.

Resistance to various chemotherapeutic agents is a major problem in success of cancer chemotherapy. One of the primary reasons of development of multidrug resistance (MDR) is the overexpression of ATP binding cassette (ABC) transporter proteins. Breast cancer resistance protein (BCRP) belongs to ABC transporter family and encoded by ABCG2 gene. BCRP is mainly expressed in MDR1 (P-glycoprotein) lacking breast cancer cells. Overexpression of BCRP leads to efflux of chemotherapeutic agents at higher rates, therefore, decreased levels of intracellular drug accumulation. Despite the fact that several chemical modulators claim to restore BCRP-mediated increased drug efflux, these modulators were shown to display various side effects, precluding their clinical use. Therefore, to reverse BCRPmediated MDR phenotype by a modulator with minimum cytotoxicity may increase clinical benefits and minimize side effects.

Sex determination in mammals is regulated by the sex-determining region on the Y chromosome (SRY); the presence of SRY activates the male developmental pathway and suppresses the gene network necessary for female gonad development. Mutations in sex determination genes lead to various abnormal sexual phenotypes, including sex reversal syndrome in which the genetic and phenotypic sex do not match. Sex reversal syndrome has been reported in humans, mouse, and several domestic species. In horses, SRY-negative XY sex reversal syndrome has been well described and is caused by deletions on the Y chromosome. However, the molecular causes of the SRY-positive condition in horses and other mammals are not known. This research investigated five horses affected with SRY-positive XY sex reversal syndrome. Sequencing of the coding exon region of the SRY gene in the five cases showed 99-100% alignment with the sequences of normal males. Genotyping of two closely related individuals with 46 normal male controls on an equine SNP50 Beadchip identified two statistically significant SNPs in a ~16 Mb region on the long arm of horse chromosome 3 (ECA3q). The region was analyzed using Gene Ontology (GO) and Gene Relationships Across Implicated Loci (GRAIL) to select functionally relevant candidate genes for sequencing. Further analysis of the entire horse genome was done through array comparative genomic hybridization (aCGH), which investigated possible structural rearrangements, such as copy number variants (CNVs). Deletions of olfactory receptor genes were detected on multiple chromosomes and confirmed through quantitative real-time PCR (qPCR). A homozygous deletion on ECA29 in a region containing genes of the aldo-keto reductase gene family, known to play a role in interconverting sex hormones between active forms and inactive forms, was discovered in two sex reversed animals. The findings were confirmed through qPCR and fluorescence in situ hybridization (FISH), and experiments to define the specific breakpoints of the deletion through PCR have been initiated. This research represents the first systematic search in the horse genome for mutations and CNVs related to sex determination. The findings contribute to better understanding of the molecular mechanisms of sex determination in horses and other mammals, including humans.

Thesis (Ph.D.)--University of Utah, 1998. / Includes bibliographical references (leaves 296-313).

Buoyant plumes in cold fresh water are of interest because of the possibility of buoyancy reversal due to the nonlinear relation between temperature and density in water. Thus an initially rising plume may become a fountain. This project aims to mathematically model such plumes and fountains using numerical simulation by the means of a commercial software, Comsol Multiphysics. Both turbulent and lam- inar cases were investigated in different geometries, and with the assumption that density is a quadratic function of temperature. The turbulent flow cases as con- sidered here in this thesis are relevant to practical applications such as industrial discharge in cold lakes: whereas, the laminar flow case relates to laboratory experi- ments which are typically at scales too small for the flow to be turbulent. Previous investigation on warm discharge placed more attention on the biological implications of the spread along the lake bed, and not interested in analysing the dynamics of such flow, which turns out to be our focus. Furthermore, investigations on buoyant plumes that become negatively buoyant at later time (fountain flow) as considered previously, are based on the assumption that density is a linear function of tem- perature: where entrainment always reduces buoyancy. Whereas, the consideration of the temperature of maximum density is crucial and realistic in many practical situations, especially the power station warm discharge. Mixing is then bound to produce a mixture that is denser than both the discharge and the ambient water if receiving water is less than Tm: where this situation differs from plumes with linear mixing properties. Therefore, our focus is to better fathom the behaviour of warm discharge so as to give a detailed description of the flow, and also to observe buoyancy reversal whenever water that is denser than both the discharge and the receiving water is produced. The simulations were carried out for Prandtl number Pr = 7 & 11.4 and over the ranges of Froude number 0.1 ≤ Fr ≤ 5 and Reynolds numbers 50 ≤ Re ≤ 106, with source temperatures that are assumed to be higher than the temperature of maximum density Tm, and the ambient water below the Tm. Our results show some distinct behaviours from those experimental investigations by Bukreev, who also considered warm discharge where water that has temperature above the temperature Tm is initiated into a medium below Tm. The results here also showed some differences from those investigations with the linear dependence relation assumption.

The dissertation thesis focuses on predator ecology in artificial water bodies. Paper I deals with the importance of chemical cues for predator-prey interactions in an aquatic environment. Here, I demonstrate that the ability to detect chemical cues represents a survival benefit for prey species. Paper II points out gillnet methodological bias, which may have subsequent repercussions in field evaluation of a predator's presence and assessment of larger fish abundance in general. Papers III and IV focus on asp Leuciscus aspius spawning grounds. In Paper III, I demonstrate how males maximize their spawning chances by early arrival and in Paper IV, I evaluate the predation pressure of asp prey, Alburnus alburnus, directed on asp eggs.

Orientador: Gil Lucio Almeida / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-05T03:20:59Z (GMT). No. of bitstreams: 1 Paulino_RodrigoGaiga_M.pdf: 1725272 bytes, checksum: bad6329e7b6f8807cc8798a0689dc64a (MD5) Previous issue date: 2005 / Resumo: Este estudo se propôs a analisar as características cinemáticas e eletromiográficas (EMG) dos movimentos voluntários uni-articulares unidirecionais e com reversão do cotovelo, em indivíduos jovens e idosos saudáveis, como também em indivíduos portadores da doença de Parkinson. Método: Os sujeitos permaneceram sentados em uma cadeira, com o antebraço direito sobre um ¿manipulandum¿ horizontal, de modo que o cotovelo direito se posicionava sobre o eixo de rotação do ¿manipulandum¿. O ombro ficou abduzido a 90°, ou seja, com o braço na horizontal. Nos movimentos unidirecionais, os sujeitos eram instruídos a mover em direção a um alvo e parar (somente flexão), já nos movimentos com reversão foi necessário realizar os movimentos em direção ao alvo e depois reverte-lo a uma nova posição (flexão e extensão). Os movimentos foram realizados em amplitudes variadas, tanto de ida, quanto de retorno do movimento. Registrou-se a atividade EMG do músculo bíceps braquial (BIC) e do tríceps cabeça lateral (TR). Os portadores da doença de Parkinson foram avaliados em dois momentos, no período em que a medicação estava em sua ação mínima (cerca de 12 horas após a ultima dose da medicação) e reavaliados 1-1,5h após a ingestão do medicamento anti-parkinsoniano. Resultados: Em indivíduos jovens e idosos saudáveis observou-se que na fase de desaceleração ao alvo ocorre a supressão da atividade do segundo burst agonista (BIC) em movimentos com reversão. Nesta mesma fase houve um aumento da magnitude da atividade EMG do antagonista (TR) com a distância de retorno. Após a reversão, a atividade EMG do TR, que nesta fase atua como agonista, continua a modular a magnitude EMG com o aumento da distância de retorno. Os portadores da doença de Parkinson moveram mais lentamente que os indivíduos idosos saudáveis, diminuindo a magnitude dos bursts EMG durante a aceleração nos movimentos de ida e nos de retorno. No momento da desaceleração os parkinsonianos apresentaram um aumento na co-ativação entre o agonista e o antagonista. Após a medicação, os parkinsonianos moveram mais rapidamente e mostraram um aumento na magnitude da atividade EMG na fase de aceleração dos movimentos. Discussão: Os resultados demonstraram que o envelhecimento não modifica a modulação dos padrões de ativação EMG. A supressão do segundo burst agonista (BIC) otimiza a função do antagonista (TR) que atua desacelerando o membro. Na fase subsequente o TR acelera o membro em direção à posição inicial. O aumento da magnitude da atividade EMG do TR com a distância de retorno sugere que o sistema nervoso central gera a atividade EMG capaz de não apenas desacelerar o membro ao alvo, mas também reverter sua direção e lançá-lo de volta à posição inicial. Os portadores da doença de Parkinson apresentaram múltiplos bursts de aceleração de pequena magnitude, que levam o parkinsoniano a mover lentamente. A co-ativação entre o agonista e o antagonista no momento da desaceleração do movimento aumentou a estabilidade para que o movimento fosse revertido com mais precisão. Por fim, o uso da medicação anti-parkinsoniana sugere a melhora do planejamento motor durante os movimentos com reversão, aumentando a magnitude da atividade EMG durante os momentos de aceleração do movimento / Abstract: This study analyses the kinematic and electromyographic (EMG) patterns of the singlejoint unidirectional movement and with elbow reversion in young individuals, healthy elderly and also individuals with Parkinson's disease. Method: The individuals remained seated in a chair with the right forearm on a horizontal ¿manipulandum¿, so that the right elbow was placed on the ¿manipulandum¿ rotation axis. The shoulder was abducted at a 90° angle, which means, with the arm in the horizontal position. In the unidirectional movements, the individuals have been instructed to move towards a given target and stop (flexion only), whereas in the movements with reversion was necessary to perform movements towards the target and after reverse them to a new position (flexion and extension). The movements were performed in several amplitudes either forward or backward movements. Biceps biceps muscle (BIC) and also lateral head triceps (TR) EMG activities have been registered. The individuals with Parkinson's disease were evaluated in two moments, during the period when the medication was at its minimum action (about 12 hours after the last dose of the medication) and reevaluated after 1-1,5h after the ingestion of the antiparkinsonian medication. Results: It has been observed through the data obtained from young individuals and healthy elderly that a suppression of the activity of the second agonist burst (BIC) occurred during the target deceleration phase in reversion movements. In this same phase there was an increase of magnitude of the activity EMG of the antagonist (TR) with the return distance. After the reversion, the EMG activity of the TR, which in this phase acts as agonist, continues to modulate the magnitude with the increase of the return distance. The individuals with Parkinson's disease moved more slowly than the healthy elderly, decreasing the magnitude of the bursts EMG during the acceleration in forward and backward movements. In the moment of the deceleration the pakinsonians presented an increase in the co-activation between the agonist and the antagonist. After the medication was taken, the parkinsonians were able to move faster and showed an increase in the magnitude of the EMG activity during the acceleration phase of the movements. Discussion: The results have demonstrated that the aging process does not modify the modulations of the EMG activation patterns. The suppression of the second agonist burst (BIC) optimizes the antagonist (TR) function, which acts by decelerating the member. During the following phase, the TR accelerates the member towards the initial position. The increase of the magnitude of the EMG activity of the TR with the return distance suggests that the central nervous system generates the EMG activity which is capable of not only decelerating the limb to the target, but also of reversing its direction and cast it back to the initial position. The Parkinson disease subjects presented multiples bursts of short magnitude in acceleration phase, which make the parkinsonian move slowly. The co-activation between the agonist and the antagonist during the movement deceleration moment increased the stability so that the movement could be more precisely reverted. Finally, the anti-parkinsonian suggests the improvement of the motor planning during the movements with reversion, increasing the magnitude of the EMG activity during the moments of acceleration of the movement / Mestrado / Fisiologia / Mestre em Biologia Funcional e Molecular

Orientador: Celso Aparecido Bertran / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T16:03:35Z (GMT). No. of bitstreams: 1 CarinhanaJunior_Dermeval_D.pdf: 1993187 bytes, checksum: 8551883498a0459ecaf6e225dd799789 (MD5) Previous issue date: 2006 / Doutorado / Físico-Química / Doutor em Quimica

We consider the inverse source problem arising in thermo-and photoacoustic tomography. It consists in reconstructing the initial pressure from the boundary measurements of the acoustic wave. Our goal is to extend versatile time reversal techniques to the case when the boundary of the domain is perfectly reflecting, effectively turning the domain into a reverberant cavity. Standard time reversal works only if the solution of the direct problem decays in time, which does not happen in the setup we consider. We thus propose a novel time reversal technique with a nonstandard boundary condition. The error induced by this time reversal technique satisfies the wave equation with a dissipative boundary condition and, therefore, decays in time. For larger measurement times, this method yields a close approximation; for smaller times, the first approximation can be iteratively refined, resulting in a convergent Neumann series for the approximation.

<p>Using self-reports from 83 military connected youths, the results of the present study challenge convention, suggesting first that the best fitting model for youth’s non-normative caregiving behaviors includes three distinct behavior types: Parentification, Adultification, Role Reversal. Second, that while non-normative caregiving behaviors may be associated with youths’ socio-emotional well-being, how these behaviors are associated may depend on both the behavior and the outcome. Lastly, that Unfairness significantly moderates the association between youth’s non-normative caregiving behavior types and socio-emotional wellbeing. Implications and directions for future research on youths’ non-normative caregiving experiences and types of non-normative caregiving behaviors are considered.</p>