Thesis (Ph. D.)--University of Oregon, 2004. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 268-279). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 95-97). Also available for download via the World Wide Web; free to University of Oregon users. Address:http://wwwlib.umi.com/cr/uoregon/fullcit?p9957570.

Consensus opinion suggests that apoptosis occurs when the intracellular redox potential reaches its oxidative range, i.e. when the balance between oxidants and reductants is disturbed. An understanding of the links between redox potential and the induction of apoptosis in cells could improve our understanding of the process and help to predict therapeutic responses. This study investigates the changes in redox potential at distinct stages of apoptosis induced in the human cervical cancer cell line, HeLa. Stages of the apoptotic process were defined by loss of mitochondrial membrane polarisation (ΔΨm), membrane phosphatidyl serine exposure, caspase-3 activation, and nuclear fragmentation. To measure real-time redox potential change in apoptotic cells two independent methods were used: (1) expression of redox-responsive green fluorescent protein (roGFP2) measured by flow cytometry and (2) redox-responsive nanosensors detected by surface enhanced Raman spectroscopy (SERS). roGFP2 measurements showed that HeLa cells demonstrate a shift towards an oxidative redox state during the later stages of apoptosis and this was preceded by loss of ΔΨm. The relationship between these two events was investigated by transient inhibition of mitochondrial permeability transition pore opening using the inhibitor bongkrekic acid (BKA) pre-treatment. At the cell population level, transient exclusion of the mitochondrial contribution delayed two key events of apoptosis in the first two hours measured by nuclear fragmentation and loss of ΔΨm. However, BKA treatment did not affect redox potential, reported by roGFP2, when compared with controls. Therefore, this suggests that mitochondria do not contribute towards the overall redox potential change in apoptosis. To gain insight into the significance of redox change at the earliest stages of apoptosis, single cell studies were performed. SERS, employing simultaneous redox potential and intracellular pH measurements using two synthetic nanosensors AQ-NS and MBA-NS, showed that BKA pre-treatment resulted in increased alkalinity and the cells were consequently protected from induction of apoptosis in the first thirty minutes of the kinase inhibitor staurosporine treatment. Measurements with SERS nanosensors allowed for adjustment for pH, which provides a clearer insight into redox potential dynamics, with consideration of the environment, and accurate quantitative assessment of redox at early stages of apoptosis. Together these data suggest that while roGFP2 is a valid method to use at a population level, SERS is a more sensitive method for measuring the redox potential of the cell at the early stages of apoptosis.

[pt] Este trabalho apresenta o desenvolvimento de um modelo, em tempo discreto, para a análise através de simulação em computador digital do desempenho de um sistema de comunicações móveis via satélite que utiliza modulação CPM (Continuous Phase Modulation) Esquemas que combinam códigos convolucional e CPM (CC/CPM) foram também examinados. Estes sistemas, conforme se pode observar, apresentam maior eficiência em termos da utilização de faixa de freqüência e potência, com relação ao esquema CPM puro. A seleção do esquema CC/CPM ótimo foi realizada utilizando um algoritmo eficiente para o cálculo da distância Euclideana mínima (d2min ). Novos códigos com d2min melhores foram obtidos com o emprego do codificador convolucional com realimentação. Por fim é examinada a decodificação de esquemas Codificador Convolucional/Modulador CPM combinados utilizando-se o Algoritmo-M, um Algoritmo subótimo em que a busca da seqüência transmitida é limitada. São realizadas simulações com o Algoritmo-M e compara-se com o Algoritmo ótimo (Algoritmo de Viterbi). Verifica-se que o Algoritmo M é bastante mais eficiente que o Algoritmo de Viterbi. / [en] This work presents a model for performance analysis of a Mobile Satellite Communication system which incorporates Continuous Phase Modulation (CPM) codes. The analysis is carried out by computer simulation, using a discrete-time baseband model of the communication system. The case of convolutional codes combined with CPM schemes (CC/CPM) is also examined. New codes CC/CPM with better minimum Euclidean distance were obtained with a feedback convolutional encoder. Comparison of CC/CPM and pure CPM, constrained to the same complexity, shows that the former has better performance. The performance of a system which uses CC/CPM schemes, over an additive white Gaussian noise (AWGN) channel, with M-algorithm decoding ( a limited search algorithm) is evaluated by computer simulation. The simulation results also corroborate the fact that the M- Algorithm is far more efficient than the Viterbi Algorithm.

The evolution of counseling is due in no small part to the leadership that has directed and fostered the development of the profession. That development is an ongoing process and though it may take many forms, counselor educators are called upon to act as the leaders that effect change in the field. According to the 2009 standards of the Council for Accreditation of Counseling and Related Educational Programs (CACREP), one of the primary obligations for doctoral programs is to prepare students to serve as leaders of the profession. It is not surprising then that the CACREP (2009) standards state that in addition to entry-level considerations, doctoral program admission criteria should include consideration of each applicant's professional leadership potential. Nevertheless, no guidelines exist that clarify the way in which faculty members are expected to go about determining an applicant's professional leadership potential. The purpose of this exploratory study was to gain insight into how faculty members at CACREP accredited doctoral programs assess leadership potential when screening new applicants. Specifically, this study focused on how leadership attributes (e.g., charisma) versus leadership processes (e.g., future-thinking orientation) factor into the way faculty members assess leadership potential. Participants were randomly assigned one of four study-created vignettes that described a hypothetical doctoral program applicant with varying levels of leadership attributes and processes. They were then asked to rate their "applicant's" leadership potential. A two-way ANOVA revealed that there was a significant interaction between leadership attributes and processes in that the applicant with high leadership attributes was given a higher leadership potential score than the applicant with both high leadership attributes as well as leadership processed. The results support the idea that faculty members at CACREP accredited doctoral programs tended to favor leadership attributes (e.g., charisma, sociability) in a potential leader over leadership processes (e.g., future-thinking orientation, knowledge). These findings also seem to suggest that participants somewhat penalized the applicant that also exhibited characteristics associated with leadership processes. Possible explanations for these findings as well as suggestions for future research are provided.

Orientador: Taís Maria Bauab / Banca: Rosemeire Cristina Linhari Rodrigues Pietro / Banca: Najeh Maissar Khalil / Resumo: Peperomia blanda é uma erva rupestre, pequena que cresce em fendas de rochas, nesta espécie foi verificada a presença de componentes voláteis, associações de lignanas, flavonóides, entre outros compostos. Com o objetivo de determinar o potencial biológico de P. blanda, foi estudada a atividade antibacteriana e antioxidante de extratos, frações e substâncias isoladas de suas partes aéreas e raízes, obtidas por maceração a frio. Para determinação da atividade antibacteriana foram utilizadas as técnicas de difusão em agar e microdiluição contra cepas Gram-positivas e Gramnegativas. Para determinação do potencial antioxidante foram realizados os ensaios espectrofotométricos: radical ABTS.+, HOCl, taurina-cloramina e ânion superóxido (O2 ●-), utilizando como padrões a quercetina e cisteína. Na técnica de difusão em agar, 100μL de suspensão bacteriana a concentração de 108 UFC/mL foram semeadas em agar Muller-Hinton com alça de Drigalski. Discos de papel com 10 mm de diâmetros embebidos com 25μL das amostras vegetais foram dispostos na superfície dessas placas. Após incubação a 37ºC por 24 horas em aerobiose foram feitas as leituras dos halos de inibição de crescimento ao redor dos discos, medidos em milímetros. No teste de microdiluição os orifícios das microplacas foram preenchidos com 80μL de caldo de Muller-Hinton, 100μL de soluções da amostra vegetal diluída seriadamente de 1000 a 12,5μg/mL e 20μL da cultura bacteriana a concentração de 107 células/mL. As microplacas foram incubadas a 37ºC durante 24 horas sob condições de aerobiose e posteriormente determinada a leitura da absorbância em leitor de microplaca a 595nm. As amostras vegetais não apresentaram atividade contra nenhuma das bactérias testadas pelo método... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The species of Peperomia blanda is a perennial herb, which grows in small rocks crevices that showed the presence of volatile components, associations of lignans, flavonoids and other compounds. In order to determine the biological potential of P. blanda, we studied the antibacterial and antioxidant activity of extracts, fractions and compounds isolated from its aerial parts and roots, obtained by cold maceration. For determination the antibacterial activity was used agar diffusion and microdilution against strains Gram-positive and Gram-negative. For determination of antioxidant potential were performed spectrophotometric assay: ABTS+ radical, HOCl, taurinecloroamine and superoxide anions (O2 ●-), using quercetin and cysteine as standards. In agar diffusion assay, 100 μL of bacterial suspension in the concentration of 108 CFU/mL were placed on Mueller-Hinton agar with Drigalski. Paper disks with 10 mm in diameter embededd with 25μL samples of vegetables were placed on the surface of these plates. After incubation at 37°C for 24 hours under aerobic conditions were made the readings of the halos of growth inhibition around the disks, measured in millimeters. In the microdilution assay of the microdilutions were filled with 80μL broth Muller-Hinton, 100 μL of the solution plant sample serially diluted from 1000 to 12.5 μg/mL and 20μL of bacterial culture concentration of 107 cells/mL. The microplates were incubated at 37°C for 24 hours under aerobic conditions and thereafter determined reading the absorbance in a microplate reader 595nm.The plant samples did not show any activity against the bacteria tested using agar diffusion. Microdilution bioassay the samples showed the best results against S. aureus... (Complete abstract click electronic access below) / Mestre

Abstract Stretch of the cardiac muscle activates several physiological processes leading to changes in the function of the muscle. These changes include increase of the contraction force accompanied by changes in the intracellular calcium concentration. This phenomenon is known as Frank-Starling relation of the heart. In addition to this, stretch also influences the membrane voltage of individual myocytes predisposing the cardiac muscle to arrhythmias. In atrial muscle stretch augments the secretion of the atrial natriuretic peptide (ANP). Although several cellular components are known to be sensitive to mechanical stimulus the precise mechanisms participating to these stretch-induced changes are not known in detail. Further it is not known if these changes are causally related or if they share a common causal factor. This research was aimed to study the stretch-induced changes in the rat atrium. The possible interactive mechanisms were studied by recording intracellular action potentials, changes in the intracellular calcium concentration, contraction force and ANP secretion during stretch. The plausible mechanosensitive cellular components were incorporated into a mathematical model that was used to further study the mechanisms. The role of intracellular acidosis as a possible modulator of the mechanotransduction was of special interest. In isolated rat left atrium moderate stretch produced by increasing the intra-atrial pressure increased the contraction force in a biphasic manner. The immediate increase of the force was caused by altered properties of the contractile element, but the following slow increase was accompanied by an increase of the Ca2+ transient. These changes were followed by lengthening of the late phase of action potentials and augmented secretion of the ANP. Intensive sustained stretch was also found to induce delayed afterdepolarizations (DADs). Gadolinium (Gd3+), blocker of stretch-activated ion channels reduced the stretch-dependent activation of the contraction and inhibited the stretch-induced DADs. The mathematical model simulated the experimental findings at best when stretch-activated channel (SA-channel) activation and increased troponin-C affinity were used to mimic the stretch. The modelling data suggested that the SA-channel current increases the sarcoplasmic reticulum calcium content in a time dependent manner leading to Ca2+ transient augmentation during systole. Bigger Ca2+ transients induce a depolarizing current during the late phase of the action potential (AP) repolarization via the Na+/Ca2+ exchanger causing the lengthening of the action potentials. A small reduction of the intracellular pH (0.18 units) with 20 mM propionate was found to modulate the stretch-induced changes in the rat atrium. Acidosis leads to an increase in the diastolic [Ca2+]i during stretch, inhibits the stretch-induced changes in action potentials and slows down the contraction development during stretch by inhibiting the fast component of the force increase. These changes in E-C-coupling (excitation-contraction-coupling) were accompanied by a simultaneous augmentation of the ANP secretion. Furthermore, it was shown that contraction force and diastolic [Ca2+]i of the stretched tissue are more sensitive to acidosis than in non-stretched tissue. In conclusion, the stretch-induced changes in rat atrial myocytes are mediated by at least two mechanisms; stretch-activated Ca2+ influx and change in the properties of the contractile element. The action potential changes can be largely explained by modulation of the membrane voltage by intracellular calcium via Na+/Ca2+-exchanger. The co-occurrence of the changes in the [Ca2+]i and ANP secretion suggests that the stretch-induced ANP secretion can be mediated by [Ca2+]i.

What modern game theorists describe as fictitious play is not the learning process George W. Brown defined in his 1951 paper. Brown's original version differs in a subtle detail, namely the order of belief updating. In this note we revive Brown's original fictitious play process and demonstrate that this seemingly innocent detail allows for an extremely simple and intuitive proof of convergence in an interesting and large class of games: nondegenerate ordinal potential games.

The aim of the present study was to determine if the breeding potential of 25-month old, extensively kept, Bonsmara beef bulls can be predicted from production data, spermatozoal characteristics and/or blood hormone concentrations at that age. A further objective of the study was to determine if any of the above mentioned criteria could be associated with the libido of these bulls. Forty-one Bonsmara bulls were included in an on-farm performance test (Phase D1 growth test) for a period of 180 days. At an average age of 24.7 months, blood sampling took place (before and after GnRH treatment) and the bulls were subjected to a libido test, after which further blood samples were collected. Blood sample were analysed for cortisol and testosterone concentrations. The bulls were also subjected to an Overall Breeding Soundness Evaluation. This procedure involves an evaluation of the physical genitalia of the bulls, a measurement of scrotal circumference and semen evaluation. For purposes of statistical analyses the bulls were categorised into independent breeding potential categories according to the scores they obtained for the measured reproductive traits. The categories included scrotal circumference, spermatozoal morphology and motility and the overall breeding soundness category. A statistical analysis of the data was done by using the general linear models (GLM) procedure of the Statistical Analyses System (SAS version 8.2 BMDP). The production and growth measurements of the Bonsmara bulls did not differ between any of the high and low fertility categories and can not be used to predict the breeding potential of young bulls. The correlation between pre-weaning growth rate and the percentage morphologically normal spermatozoa was positive (r = 0.33; P<0.1), suggesting that relatively high growth rates before weaning may have a positive effect on potential fertility under normal extensive feeding conditions. By contrast, numeric differences in growth after weaning suggest that a high growth rate after weaning may have a negative effect on potential fertility. The results showed that the overall breeding soundness categories tended to be influenced by the pre-weaning growth rate (r = 0.24; P>0.1) and body lengths (r = 0.18; P>0.1) of bulls. Sampling time had a statistically significant effect on blood cortisol and testosterone concentrations for all of the breeding potential categories. Testosterone concentration increased significantly (P<0.001) after GnRH treatment. High plasma cortisol concentrations were associated with low plasma testosterone concentrations. High testosterone concentrations were associated with less spermatozoal morphological defects (r = - 0.21; P>0.1). The testosterone concentrations before GnRH treatment was higher for bulls with exceptional fertility (P<0.05), while testosterone concentration after GnRH treatment tended to be higher (P<0.1) for the bulls with acceptable fertility. This observation may be explained by the negative feedback system that operates between LH and testosterone secretion. The percentage spermatozoal defects were influenced to a greater extent by morphological abnormalities leading to reduced motility of the sperm than by any other abnormalities. From the results it seems that the semen morphology category is a better indicator of semen quality than the SC and semen motility categories. Overall breeding soundness classifications of bulls were largely influenced by spermatozoal motility (P<0.001) and to a lesser extend by spermatozoal morphology and SC. None of the reproductive and production measurements showed a correlation with libido scores, implying that optimal bull reproductive evaluation should include the assessment of both breeding soundness and libido. / Dissertation (MSc(Agric))--University of Pretoria, 2009. / Animal and Wildlife Sciences / unrestricted

This study involves the synthesis and structural characterization of new metal complexes of thiophene derivatives that have (potential) liquid crystalline properties. Thiophene has been selected because of its stability and versatility in lending itself to synthetic modification and hence forms links in chain structures for rod-like metallomesogens. Thiophene, when compared with 1,4-disubstituted benzene units, can change considerably the polarity, polarizability and also the geometry of the compounds, altering the types of mesophases, phase transition temperatures, dielectric constants and other properties of mesogens. The reactions of a series of 5-alkyl-2-thiophenedithiocarboxylates with nickel(II) chloride formed two types of complexes, blue mononuclear nickel(II) complexes with two terminal dithiocarboxylate ligands, [Ni(S2CTR)2] (T = 2,5-disubstituted thiophene) and violet mononuclear nickel(II) complexes with perthio- and dithiocarboxylate ligands, [Ni(S3CTR)(S2CTR)] (R = alkyl groups). The blue monomers are preferred for the shorter alkyl chains (C4 and C6), and the violet compounds for the longer chain lengths (C8, C12 and C16) in the alkylthiophene complexes. In addition to the above series, [Ni(S2CTCH3)2], was prepared in a one-pot reaction and it was possible to isolate both the blue and violet products. The thermal properties of the complexes were studied by using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Nickel complexes of the violet type with longer alkyl chains showed liquid crystalline properties. Zinc(II) complexes analogous to nickel(II) complexes prepared similarly. A crystal structure determination of one of those complexes revealed the fusion of two monomers to give a dimeric structure with bridging sulfur atoms, [Zn2 (ƒÝ-S2CTR) 2 (S2CTR) 2]. Although an irregular melting pattern was observed, the complexes did not show any liquid crystalline properties. In an attempt to extend the study towards organometallic compounds, complexes of the type [Re(CO) 4 (S2CTR)] or [Re(CO) 4 (S2CTTR)] (T = 2,5-disubstituted thiophene, TT = 2,5-disubstituted bithiophene; R = H, CH3, C14H29) were synthesized and characterized by IR and NMR spectroscopy. Further characterization of [Re(CO) 4 (S2CTTH)] by single crystal X-ray diffraction confirmed the molecular structure of the complexes. These compounds showed sharp single melting points. Fischer-type carbene complexes of manganese(I) with octahedral coordination of the type [MnMeCp(CO) 2{C(OEtTR)}] or [MnMeCp(CO) 2{C(OEtTTR)}] (R = H, C6H13, C12H25, C16H33) were synthesized and characterized by IR, NMR and mass spectrometry. Thermal properties of the complexes were studied by using thermogravimetric analysis (TGA). All the organometallic rhenium(I) and Fischer-type carbene complexes of manganese(I) showed weight loss upon heating due to decomposition. Therefore it can be assumed that these complexes are not suitable as liquid crystals. / Thesis (PhD (Chemistry))--University of Pretoria, 2006. / Chemistry / unrestricted