Construção de modelos para médias e variâncias na otimização experimental de produtos e processos /

Tese (Doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico

Engineering muscle networks in 3D gelatin methacryloyl hydrogels: influence of mechanical stiffness and geometrical confinement

In this work, the influence of mechanical stiffness and geometrical confinement on the 3D culture of myoblast-laden gelatin methacryloyl (GelMA) photo-crosslinkable hydrogels was evaluated in terms of in vitro myogenesis. We formulated a set of cell-laden GelMA hydrogels with a compressive modulus in the range 1÷17 kPa, obtained by varying GelMA concentration and degree of cross-linking. C2C12 myoblasts were chosen as the cell model, to investigate the supportiveness of different GelMA hydrogels on myotube formation up to 2 weeks. Results showed that the hydrogels with a stiffness in the range 1÷3 kPa provided enhanced support to C2C12 differentiation in terms of myotube number, rate of formation and space distribution. Finally, we studied the influence of geometrical confinement on myotube orientation by confining cells within thin hydrogel slabs having different cross-sections: i) 2000×2000 m, ii) 1000×1000 m and iii) 500×500 m. The obtained results showed that by reducing the cross-section—i.e., by increasing the level of confinement—myotubes were more likely restrained and formed aligned myostructures that better mimicked the native morphology of skeletal muscle

Determinantes da divulgação dos principais assuntos de auditoria nas companhias não financeiras da B3

This research analyzes the determinants of the quantity of key audit matters (KAM) reported in audit reports from 2016 to 2019 of the non-financial companies listed on B3. The longitudinal regression model for panel data - Poisson’s Log-Linear was applied to an annual sample of at least 272 companies, resulting in 1,198 reports and 3,295 KAM (dependent variable), considering as explanatory variables the aspects of the auditor, the auditee, and corporate governance mechanisms. The findings demonstrate that being audited by the big four is negatively associated with the quantity of KAM. This may be due to the big four or not reporting the same mean number of KAMs per company. Auditors of larger companies, less profitable and with greater operational risk, disclose more KAM, probably aiming to ensure their independence. The audit committees were not statistically significant, not impacting the quantity of KAM reported. The results contribute to the literature on factors that affect the disclosure of KAM in a non-European context (Bepari et al., 2022) with four years of data, and to companies, auditors, and regulatory and supervisory bodies, through Poisson’s multilevel regression, which is an appropriate approach for structured counting data in clusters of relatively similar observations (panels). This advances the studies by Ferreira and Morais (2020) and Guedes et al. (2021), who used ordinary least squares (OLS), and Colares et al. (2020), who used the Chi-square test in one- or two-year analyses of characteristics that tend to establish the quantity of KAM in Brazil.Esta pesquisa analisa os determinantes da quantidade de principais assuntos de auditoria (PAA) reportados nos relatórios de auditoria no período de 2016 a 2019 das empresas não financeiras listadas na B3. Aplicou-se o modelo longitudinal de regressão para dados em painel - Log-Linear de Poisson, para uma amostra anual de no mínimo 272 companhias, resultando em 1.198 relatórios e 3.295 PAA (variável dependente), considerando como variáveis explicativas os aspectos do auditor, do auditado e mecanismos de governança corporativa. Os achados demonstram que ser auditado por big four está negativamente associado ao quantitativo de PAA. Isso pode ocorrer devido as big four ou não relatarem mesmo número médio de PAA por companhia. Auditores de empresas maiores, menos rentáveis e, com maior risco operacional divulgam mais PAA, provavelmente visando assegurar sua independência. Os comitês de auditoria não foram estatisticamente significativos, não impactando na quantidade de PAA reportados. Os resultados contribuem com a literatura sobre fatores que afetam a divulgação de PAA em um contexto não europeu (Bepari et al., 2022) com quatro anos de dados, e às empresas, auditores e órgãos de regulação e supervisão, por meio da regressão multinível de Poisson, que é uma abordagem adequada para dados de contagem estruturados em clusters de observações relativamente similares (painéis). Isso avança os estudos de Ferreira e Morais (2020) e Guedes et al. (2021) que utilizaram ordinary least squares (OLS) e Colares et al. (2020) que empregou o teste Qui-quadrado em análises de um ou dois anos de características que tendem a estabelecer a quantidade de PAA no Brasil

Multidimensionality evaluation of supply chain management integration

Integration is constantly reported in the literature as an essential feature of SCM. However, it is as difficult to define as to operationalize it, resulting in a lack of information on how to increase the level of integration among members. Thus, this research aims to evaluate the dimensionality of SCI, to check alignment with the features identified in the literature using multivariate statistical analysis. The methodology used was based on a questionnaire to assess the level of companies integration with suppliers of its supply chain. This instrument consisted of 21 items, with response options: yes, no or not applicable. The questions focused on evaluating the integration with suppliers, so each company consulted could answer a questionnaire for each supplier, since the intensity of relationships varies. Thus, 41 companies participated in the survey, resulting in 205 responses. Full-information item factor analysis and principal component analysis on the correlation matrix tetrachoric were used for the instrument dimensionality analysis. They are appropriate procedures for analysis of dichotomous variables. The results of this analysis enabled grouping the questionnaire items in the following underlying factors: trust, information sharing, partnership, collaboration or cooperation, and coordination. The identification of such factors such as dimensions of SCI enables greater understanding on how to raise the level of integration among the members of a supply chain

RR5. Surgical Treatment of Popliteal Aneurysms Using a Posterior Approach: Thirteen Years' Follow-up

OBJECTIVES : Long-term results of posterior approach (PA) for the treatment of popliteal artery aneurysms are lacking in the literature. We compared our results with this access with those from a standard medial approach over a 13-years\u2019 period. METHODS: Clinical data of all patients treated for a popliteal aneurysm between 2/1998 and 10/2011 were retrospectively reviewed and outcomes analyzed: Kaplan-Meier method with log-rank, chi2 and Wilcoxon test were employed for analysis. RESULTS : A total of 78 aneurysms were treated in 66 patients (65 men). Mean age was 68 years (range 48-96 years). Thirty-six aneurysms were asymptomatic (46%). Mean sac diameter was 2.9\ub11 cm. A PA was used in 43 cases (55%) and a medial approach (MA) in 35. All PA consisted in aneurysmectomy with an interposition graft with end to end anastomoses; among MA 25 interposition grafts and 10 bypass were performed. A PTFE graft was used mostly (57 cases). The two groups differed for age only (median 65.4 for PA vs. 72.9 for MA p=0.01). Five patients had an early thrombosis and required a Fogarty thrombectomy (2 PA and 3 MA, all PTFE grafts). Mortality rate at 30 days was 0%. One patient suffered a peroneal nerve lesion (permanent) and another one a major wound necrosis with tissue loss (both PA). There were no early amputations. Median follow-up was 58.8 months (range 5 days-166.7 months). Nine patients died during follow-up for unrelated causes. The 5-year primary and secondary patency rates were 58.9%\ub18,7% and 96.4%\ub13.5% respectively for PA, and 67.4%\ub110,4% and 81.3%\ub18,9% respectively for MA (p=0.41 for primary patency rate and 0.28 for secondary patency rate). Limb salvage was 100% and 93.3%\ub16.4% at 5 and 10 years respectively for PA and 91.5%\ub15.6% at both time points for MA (p=0.3). CONCLUSIONS : PA in our experience was burdened by a few more early complications compared to MA. However in the long term it provided results which compare favorably to MA. AUTHOR DISCLOSURES: I. Barbetta, Nothing to disclose; M. Carmo, Nothing to disclose; R. Dallatana, Nothing to disclose; G. Grava, Nothing to disclose; D. Mazzaccaro, Nothing to disclose; A. M. Settembrini, Nothing to disclose; P. Settembrini, Nothing to disclose

Impact of acute changes of left ventricular contractility on the transvalvular impedance: validation study by pressure-volume loop analysis in healthy pigs

BACKGROUND: The real-time and continuous assessment of left ventricular (LV) myocardial contractility through an implanted device is a clinically relevant goal. Transvalvular impedance (TVI) is an impedentiometric signal detected in the right cardiac chambers that changes during stroke volume fluctuations in patients. However, the relationship between TVI signals and LV contractility has not been proven. We investigated whether TVI signals predict changes of LV inotropic state during clinically relevant loading and inotropic conditions in swine normal heart. METHODS: The assessment of RVTVI signals was performed in anesthetized adult healthy anesthetized pigs (n = 6) instrumented for measurement of aortic and LV pressure, dP/dtmax and LV volumes. Myocardial contractility was assessed with the slope (Ees) of the LV end systolic pressure-volume relationship. Effective arterial elastance (Ea) and stroke work (SW) were determined from the LV pressure-volume loops. Pigs were studied at rest (baseline), after transient mechanical preload reduction and afterload increase, after 10-min of low dose dobutamine infusion (LDDS, 10 ug/kg/min, i.v), and esmolol administration (ESMO, bolus of 500 µg and continuous infusion of 100 µg·kg-1·min-1). RESULTS: We detected a significant relationship between ESTVI and dP/dtmax during LDDS and ESMO administration. In addition, the fluctuations of ESTVI were significantly related to changes of the Ees during afterload increase, LDDS and ESMO infusion. CONCLUSIONS: ESTVI signal detected in right cardiac chamber is significantly affected by acute changes in cardiac mechanical activity and is able to predict acute changes of LV inotropic state in normal heart

Instrument to measure adherence in hypertensive patients: contribution of Item Response Theory

OBJETIVO: Analizar instrumento de medición de la adhesión al tratamiento de hipertensión por medio de la "Teoría de la Respuesta al Ítem". MÉTODOS: Estudio analítico con 406 hipertensos con complicaciones asociadas, atendidos en la asistencia básica en Fortaleza, CE, Brasil, 2001 por la "Teoría de Respuesta al Ítem". Las etapas de ejecución fueron: prueba de dimensionalidad, calibración de los ítems; tratamiento de los datos y construcción de la escala, analizadas con base en el modelo de respuesta gradual. Estudio de la dimensionalidad del instrumento fue hecho por análisis de la matriz de correlación policórica y análisis factorial de información completa. Se utilizó el software Multilog para calibración de los ítems y estimación de los escores. RESULTADOS: Los ítems referentes al tratamiento medicamentoso fueron los más directamente relacionados con la adhesión, mientras que aquellos referentes al tratamiento no medicamentoso precisan ser reformulados, pues presentaron menor cantidad de información psicométrica y baja discriminación. La independencia de los ítems, el reducido número de niveles de escala y las bajas varianzas explicadas en el ajuste de los modelos mostraron las principales fragilidades del instrumento analizado. La Teoría de la Respuesta al Ítem se mostró relevante para el análisis, ya que evaluó al respondiente cuanto a la adhesión al tratamiento de la hipertensión, al nivel de dificultad de los ítems y a su capacidad de discriminación entre individuos con diferentes niveles de adhesión, lo que generó mayor cantidad de información. CONCLUSIONES: El instrumento analizado es limitado para medir la adhesión al tratamiento de la hipertensión, mediante análisis por la "Teoría de la Respuesta al Ítem" y necesita ajustes. La adecuada formulación de los ítems es importante para medir precisamente el aspecto latente deseado.OBJECTIVE: To analyze, by means of "Item Response Theory", an instrument to measure adherence to t treatment for hypertension. METHODS: Analytical study with 406 hypertensive patients with associated complications seen in primary care in Fortaleza, CE, Northeastern Brazil, 2011 using "Item Response Theory". The stages were: dimensionality test, calibrating the items, processing data and creating a scale, analyzed using the gradual response model. A study of the dimensionality of the instrument was conducted by analyzing the polychoric correlation matrix and factor analysis of complete information. Multilog software was used to calibrate items and estimate the scores. RESULTS: Items relating to drug therapy are the most directly related to adherence while those relating to drug-free therapy need to be reworked because they have less psychometric information and low discrimination. The independence of items, the small number of levels in the scale and low explained variance in the adjustment of the models show the main weaknesses of the instrument analyzed. The "Item Response Theory" proved to be a relevant analysis technique because it evaluated respondents for adherence to treatment for hypertension, the level of difficulty of the items and their ability to discriminate between individuals with different levels of adherence, which generates a greater amount of information. CONCLUSIONS: The instrument analyzed is limited in measuring adherence to hypertension treatment, by analyzing the "Item Response Theory" of the item, and needs adjustment. The proper formulation of the items is important in order to accurately measure the desired latent trait.OBJETIVO: Analisar instrumento de medição da adesão ao tratamento da hipertensão por meio da "Teoria da Resposta ao Item". MÉTODOS: Estudo analítico com 406 hipertensos com complicações associadas, atendidos na atenção básica em Fortaleza, CE, 2011, pela "Teoria da Resposta ao Item". As etapas de execução foram: teste de dimensionalidade, calibração dos itens; tratamento dos dados e construção da escala, analisadas com base no modelo de resposta gradual. Estudo da dimensionalidade do instrumento foi feito pela análise da matriz de correlação policórica e análise fatorial de informação completa. Utilizou-se o software Multilog para calibração dos itens e estimação dos escores. RESULTADOS: Os itens referentes ao tratamento medicamentoso foram os mais diretamente relacionados à adesão, enquanto aqueles referentes ao tratamento não medicamentoso precisam ser reformulados, pois possuíram menor quantidade de informação psicométrica e baixa discriminação. A independência dos itens, o reduzido número de níveis da escala e as baixas variâncias explicadas no ajuste dos modelos mostraram as principais fragilidades do instrumento analisado. A "Teoria da Resposta ao Item" mostrou-se relevante para análise, pois avaliou o respondente quanto à adesão ao tratamento da hipertensão, ao nível de dificuldade dos itens e à sua capacidade de discriminação entre indivíduos com diferentes níveis de adesão, o que gerou maior quantidade de informação. CONCLUSÕES: O instrumento analisado é limitado para medir a adesão ao tratamento da hipertensão, mediante análise pela "Teoria da Resposta ao Item", e necessita de ajustes. A adequada formulação dos itens é importante para medir precisamente o traço latente desejado

Measuring the quality of life in hypertension according to Item Response Theory

OBJECTIVE To analyze the Miniquestionário de Qualidade de Vida em Hipertensão Arterial (MINICHAL – Mini-questionnaire of Quality of Life in Hypertension) using the Item Response Theory. METHODS This is an analytical study conducted with 712 persons with hypertension treated in thirteen primary health care units of Fortaleza, State of Ceará, Brazil, in 2015. The steps of the analysis by the Item Response Theory were: evaluation of dimensionality, estimation of parameters of items, and construction of scale. The study of dimensionality was carried out on the polychoric correlation matrix and confirmatory factor analysis. To estimate the item parameters, we used the Gradual Response Model of Samejima. The analyses were conducted using the free software R with the aid of psych and mirt. RESULTS The analysis has allowed the visualization of item parameters and their individual contributions in the measurement of the latent trait, generating more information and allowing the construction of a scale with an interpretative model that demonstrates the evolution of the worsening of the quality of life in five levels. Regarding the item parameters, the items related to the somatic state have had a good performance, as they have presented better power to discriminate individuals with worse quality of life. The items related to mental state have been those which contributed with less psychometric data in the MINICHAL. CONCLUSIONS We conclude that the instrument is suitable for the identification of the worsening of the quality of life in hypertension. The analysis of the MINICHAL using the Item Response Theory has allowed us to identify new sides of this instrument that have not yet been addressed in previous studies.OBJETIVO Analisar o Miniquestionário de Qualidade de Vida em Hipertensão Arterial (MINICHAL) por meio da Teoria da Resposta ao Item. MÉTODOS Estudo analítico realizado com 712 pessoas com hipertensão arterial atendidas em 13 unidades de atenção primária em saúde de Fortaleza, CE, em 2015. As etapas da análise pela Teoria da Resposta ao Item foram: avaliação da dimensionalidade, estimação dos parâmetros dos itens e construção da escala. O estudo da dimensionalidade foi realizado sobre a matriz de correlação policórica e análise fatorial confirmatória. Para a estimação dos parâmetros dos itens, foi utilizado o Modelo de Resposta Gradual de Samejima. As análises foram conduzidas no software livre R com o auxílio dos pacotes psych e mirt. RESULTADOS A análise permitiu a visualização dos parâmetros dos itens e suas contribuições individuais na mensuração do traço latente, gerando mais informação, permitindo a construção de uma escala com um modelo interpretativo que demonstra a evolução da piora da qualidade de vida em cinco níveis. Quanto aos parâmetros dos itens, houve bom desempenho daqueles referentes ao estado somático, pois apresentaram melhor poder de discriminar os indivíduos com pior qualidade de vida. Os itens relacionados ao estado mental foram os que contribuíram com menor quantidade de informação psicométrica no MINICHAL. CONCLUSÕES Conclui-se que o instrumento é indicado para a identificação da deterioração da qualidade de vida em hipertensão arterial. A análise do MINICHAL pela Teoria da Resposta ao Item permitiu identificar novas facetas desse instrumento ainda não abordadas em estudos anteriores