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A Monte Carlo simulation technique was employed in this study to determine if the r transformation, a test of homogeneity of variance, affords adequate protection against Type I error over a range of equal sample sizes and number of groups when samples are obtained from normal and non-normal distributions. Additionally, this study sought to determine if the r transformation is more robust than Bartlett's chi-square to deviations from normality. Four populations were generated representing normal, uniform, symmetric leptokurtic, and skewed leptokurtic distributions. For each sample size (6, 12, 24, 48), number of groups (3, 4, 5, 7), and population distribution condition, the r transformation and Bartlett's chi-square were calculated. This procedure was replicated 1,000 times; the actual significance level was determined and compared to the nominal significance level of .05. On the basis of the analysis of the generated data, the following conclusions are drawn. First, the r transformation is generally robust to violations of normality when the size of the samples tested is twelve or larger. Second, in the instances where a significant difference occurred between the actual and nominal significance levels, the r transformation produced (a) conservative Type I error rates if the kurtosis of the parent population were 1.414 or less and (b) an inflated Type I error rate when the index of kurtosis was three. Third, the r transformation should not be used if sample size is smaller than twelve. Fourth, the r transformation is more robust in all instances to non-normality, but the Bartlett test is superior in controlling Type I error when samples are from a population with a normal distribution. In light of these conclusions, the r transformation may be used as a general utility test of homogeneity of variances when either the distribution of the parent population is unknown or is known to have a non-normal distribution, and the size of the equal samples is at least twelve.

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Organic photovoltaic (OPV) devices are emerging as a reliable source of energy due to their combination of unique features. Though desired for their flexibility, low cost, light weight, large area fabrication compatibility and eco-friendly nature, these devices face numerous challenges in achieving high performance and stability. The organic-electrode interface specifically plays a key role in controlling device stability. Recent studies have revealed that the stability is heavily affected by the adhesion of the organic-electrode interface. Measurement of adhesion at these interfaces, however, is a challenging task. In this study, Normal Force Adhesion testing was assessed to determine its suitability for organic devices. In this approach, force is applied perpendicular to the substrate, over the entire surface area of one device (9 mm2) until delamination occurs. In addition to the extracted force-distance curves, images of the interfaces before and after each experiment and a real-time, in-situ video taken from a lateral perspective were examined. All three of these critical pieces of information are necessary to obtain a complete picture of the success of a Normal test. A statistical assessment has been made of the testing apparatus, using many samples (> 50) of one metal - organic combination, Al-Alq3 - an archetypal combination for organic electronics. In addition, five other metal-organic combinations widely used in organic electronic devices, have been chosen to assess the Normal force approach. Due to the ease of testing a large number of samples, Normal force testing does appear to be a viable approach to examining interfacial adhesion, though care must be taken in the experimental design to avoid common experimental failures. Based on the results, a few recommendations have been made to improve the utility of the adhesion testing system for rapid quality testing of organic devices. / Thesis / Master of Applied Science (MASc)

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BACKGROUND: In applications on dental/orthopedic implants and bone regeneration, biomaterials contained magnesium have been widely used. However, the mechanism underlying the biologic effects is still largely unknown. In addition, previous reports of osteogenic effect of magnesium mainly relied on studies using ATCC osteosarcoma cell lines but not normal human osteoblasts. OBJECTIVE: This study was designed to test the effect of magnesium on osteogenic phenotypic behaviors of normal human osteoblasts. METHODS: Normal human osteoblasts derived from human alveolar bone were cultured in triplicate in growth media with varies concentrations of supplemental magnesium: 0.5mM, 1mM, 2mM, 4mM, 8mM and 16mM as the study groups and 0mM as a control group for the time intervals of 7 days, 10 days, 14 days and 21days. Cell proliferation was measured by crystal violet dye staining. Expression of osteocalcin was measured by Quantikine Elisa and mineralization of cultures was measured by Alizarin Red staining. The data were normalized per cell basis. Statistical analysis was done using ANOVA and Student’s t test. Results: Osteocalcin expression was upregulated in groups with supplemented magnesium at 0.5mM (1.16folds, p<0.01 ), 1.0mM (1.22folds, p<0.01 ), 2.0mM (1.37folds, p<0.01 ) at day 21 compared to control, while at 4mM ( p<0.01 ) and above showed down-regulation. Alizarin Red stained cultures showed higher degree of mineralization at 1mM ( p=0.0228 ) and 2mM ( p=0.0142) compared to control. Groups with 4mM and above showed less calcium deposition. Similar results have been gained also on day 10 and day 14 for both assays. CONCLUSION: Osteogenesis of normal human osteoblasts could be significantly upregulated by 2mM supplemental magnesium. These data are important for manufacturing magnesium-containing biomaterials for bone tissue regeneration and implants.

In multivariate statistical process control it is generally assumed that the process variables follow a multivariate normal distribution with mean vector " and covariance matrix •, but this is rarely satisfied in practice. Some robust control charts have been developed to monitor the mean and variance of univariate processes, or the mean vector " of multivariate processes, but the development of robust multivariate charts for monitoring • has not been adequately addressed. The control charts that are most affected by departures from normality are actually the charts for • not the charts for ". In this article, the robust design of several MEWMA-type control charts for monitoring • is investigated. In particular, the robustness and efficiency of different MEWMA-type control charts are compared for the in-control and out-of-control cases over a variety of multivariate distributions. Additionally, the total extra quadratic loss is proposed to evaluate the overall performance of control charts for multivariate processes. / Ph. D.

Introducción: El infarto agudo de miocardio con coronariografía normal, más conocido por sus siglas en inglés como MINOCA, es un cuadro clínico menos estudiado a diferencia de su contraparte obstructiva. Objetivo: Describir características generales de los pacientes con infarto agudo de miocardio y coronariografía normal en un hospital de tercer nivel del 2016 al 2021. Materiales y métodos: El estudio es de diseño observacional, transversal y descriptivo. Se usaron datos recolectados de las historias clínicas mediante una ficha de datos. Se realizó un muestreo censal que incluyó 54 registros clínicos. Resultados: La mayoría de los pacientes fueron mujeres (62.9%), y mayores de 60 años (61.1%). Como factores de riesgo destacó la hipertensión arterial (63%), seguido de diabetes mellitus (29.6%) y dislipidemia (18.5%). Predominó el sobrepeso y la obesidad (72,3%). En el trazado electrocardiográfico la mayoría presentó un trazado sin elevación del segmento ST (74.1%), y al examen ecocardiográfico la mitad de los pacientes presentaron motilidad cardiaca normal (51,9%) y una FEVI preservada (59,3%). Respecto a los diagnósticos al alta, se encontró en primer lugar el infarto agudo de miocardio tipo 1 (59.3%). Conclusión: Se encontró que el MINOCA afecta principalmente a pacientes que se caracterizan por ser del sexo femenino, mayores de 60 años, con diagnóstico previo de HTA, presentar dolor torácico típico, cursar con sobrepeso, además de registrar electrocardiogramas sin elevación del segmento ST, conservar una motilidad cardiaca normal y FEVI preservada, y la mayoría fue dado de alta con infarto de miocardio tipo 1. / Introduction: Acute myocardial infarction with normal coronary angiography, better known by its acronym in English as MINOCA, is a clinical condition less studied unlike its well-known obstructive counterpart. Objective: To describe general characteristics of patients with acute myocardial infarction and normal coronary angiography in a tertiary hospital from 2016 to 2021. Materials and methods: The study has an observational, cross-sectional, and descriptive design. Data collected from medical records using a data sheet were used. A census sampling was carried out that included 54 clinical records. Results: Most of patients were women (62.9%), and over 60 years of age (61.1%). High blood pressure (63%) stood out as risk factors, followed by diabetes mellitus (29.6%) and dyslipidemia (18.5%). Also, there was a clear predominance of overweight and obesity (72.3%). In the electrocardiographic tracing, the majority presented a tracing without ST segment elevation (74.1%), and in the echocardiographic examination, half of the patients presented normal cardiac motility (51.9%) and a preserved LVEF (59.3%). Regarding the diagnoses at discharge, acute myocardial infarction type 1 was found in first place (59.3%). Conclusion: It was found that MINOCA affects patients who are characterized by being female, over 60 years of age, with a previous diagnosis of arterial hypertension, presenting typical chest pain, being overweight, in addition to recording electrocardiograms without ST segment elevation. maintained normal cardiac motility and preserved LVEF, and the majority were discharged with type 1 myocardial infarction.

<p> The estimators of the mean, standard deviation and group effects for one-way-classification experimental designs are obtained from type I censored samples. The bias and the variances and covariances of these estimators are evaluated. A test statistic is proposed for testing a linear contrast of the group-effects. Two numerical examples are presented.</p> / Thesis / Master of Science (MSc)