Impact of Syncope on Quality of Life: Validation of a Measure in Patients Undergoing Tilt Testing

INTRODUCTION AND OBJECTIVES: Recurrent syncope has a significant impact on quality of life. The development of measurement scales to assess this impact that are easy to use in clinical settings is crucial. The objective of the present study is a preliminary validation of the Impact of Syncope on Quality of Life questionnaire for the Portuguese population. METHODS: The instrument underwent a process of translation, validation, analysis of cultural appropriateness and cognitive debriefing. A population of 39 patients with a history of recurrent syncope (>1 year) who underwent tilt testing, aged 52.1 ± 16.4 years (21-83), 43.5% male, most in active employment (n=18) or retired (n=13), constituted a convenience sample. The resulting Portuguese version is similar to the original, with 12 items in a single aggregate score, and underwent statistical validation, with assessment of reliability, validity and stability over time. RESULTS: With regard to reliability, the internal consistency of the scale is 0.9. Assessment of convergent and discriminant validity showed statistically significant results (p<0.01). Regarding stability over time, a test-retest of this instrument at six months after tilt testing with 22 patients of the sample who had not undergone any clinical intervention found no statistically significant changes in quality of life. CONCLUSIONS: The results indicate that this instrument is of value for assessing quality of life in patients with recurrent syncope in Portugal.

Validation of Two US Risk Scores for Percutaneous Coronary Intervention in a Single-Center Portuguese Population of Patients with Acute Coronary Syndrome

INTRODUCTION: New scores have been developed and validated in the US for in-hospital mortality risk stratification in patients undergoing coronary angioplasty: the National Cardiovascular Data Registry (NCDR) risk score and the Mayo Clinic Risk Score (MCRS). We sought to validate these scores in a European population with acute coronary syndrome (ACS) and to compare their predictive accuracy with that of the GRACE risk score. METHODS: In a single-center ACS registry of patients undergoing coronary angioplasty, we used the area under the receiver operating characteristic curve (AUC), a graphical representation of observed vs. expected mortality, and net reclassification improvement (NRI)/integrated discrimination improvement (IDI) analysis to compare the scores. RESULTS: A total of 2148 consecutive patients were included, mean age 63 years (SD 13), 74% male and 71% with ST-segment elevation ACS. In-hospital mortality was 4.5%. The GRACE score showed the best AUC (0.94, 95% CI 0.91-0.96) compared with NCDR (0.87, 95% CI 0.83-0.91, p=0.0003) and MCRS (0.85, 95% CI 0.81-0.90, p=0.0003). In model calibration analysis, GRACE showed the best predictive power. With GRACE, patients were more often correctly classified than with MCRS (NRI 78.7, 95% CI 59.6-97.7; IDI 0.136, 95% CI 0.073-0.199) or NCDR (NRI 79.2, 95% CI 60.2-98.2; IDI 0.148, 95% CI 0.087-0.209). CONCLUSION: The NCDR and Mayo Clinic risk scores are useful for risk stratification of in-hospital mortality in a European population of patients with ACS undergoing coronary angioplasty. However, the GRACE score is still to be preferred.

Validation of NASA rotor 67 with openFOAM's transonic density-based solver

Dissertação para obtenção do Grau de Mestre em Engenharia Mecânica

Validation of alternative additives for paste production

Dissertation presented to confer Master Degree in Chemical and Biochemical Engineering

Validação e aplicação clínica de uma escala de cognição social na esquizofrenia = Validation and clinical use of a measure of social cognition in schizophrenia

RESUMO: A cognição social encontra-se frequentemente alterada na esquizofrenia. Esta alteração relaciona-se com a diminuição do funcionamento social,caracterizando-se quer por défices quer por vieses cognitivos sociais. No entanto, existem poucos instrumentos fiáveis e válidos para avaliar a cognição social na esquizofrenia, nomeadamente capazes de medir os vieses cognitivos sociais e a cognição social auto-relevante. Adicionalmente, as bases biológicas da disfunção social não estão totalmente esclarecidas. Evidências recentes sugerem que o peptídeo oxitocina (OXT) influencia o funcionamento social, e que esta relação poderá ser mediada pela cognição social. Este Trabalho de Projecto descreve a contribuição do autor para o desenvolvimento e avaliação psicométrica inicial de um novo instrumento de avaliação da cognição social, e a utilidade desta escala na investigação das associações entre a OXT e a capacidade e vieses cognitivos sociais. A Waiting Room Task (WRT), uma escala constituída por 26 vídeos sequenciais que simulam a experiência de observar outra pessoa numa sala de espera, foi administrada num estudo transversal com 61 doentes com esquizofrenia e 20 controlos saudáveis. Observou-se uma menor capacidade cognitiva social e um aumento dos vieses cognitivos sociais nos doentes com esquizofrenia, comparativamente aos controlos. Nos controlos e doentes com delírios, o desempenho na WRT correlacionou-se significativamente com os níveis de OXT. Esta correlação não se observou nos doentes sem delírios, sugerindo que o papel da OXT na cognição social poderá encontrar-se atenuado neste grupo. Estes achados fornecem suporte inicial para a adequação da WRT como instrumento de avaliação da cognição social na esquizofrenia, podendo ainda ser útil na investigação da sua base biológica. ------------ ABSTRACT: Social cognition is often impaired in schizophrenia. This impairment is related to poor social functioning and is characterized by both social cognitive deficits and biases. However, there are few reliable and valid measures of social cognition in schizophrenia, particularly measures of social cognitive bias and of self-relevant social cognition. Also, the biological bases of social dysfunction are not well understood. Emerging evidence suggests that the peptide oxytocin (OXT) influences social functioning, and that this relationship may be mediated by social cognition. This Research Project describes the author’s contribution to the development and initial psychometric testing of a new measure of social cognition, and the utility of this instrument to examine associations between OXT and social cognitive capacity and bias. The Waiting Room Task WRT), a video-based test comprising 26 sequential videos simulating the experience of facing another person in a waiting room, was administered in a cross-sectional study involving 61 patients with schizophrenia and 20 healthy controls. Social cognitive capacity was lower and social cognitive bias was increased in patients with schizophrenia compared with controls. Among controls and patients with delusions, performance on the WRT was significantly correlated with OXT level. This correlation was not found in patients without delusions suggesting that OXT’s role in social cognition may be blunted in this group. These findings provide initial support for the adequacy of the WRT as a measure for assessing social cognition in schizophrenia that may also be useful in understanding its biological underpinnings.

Exploring the experience of stigma in severe mental illness : a Portuguese contribution to the validation of a psychometric instrument

RESUMO: Fizemos uma análise da evolução do conceito de estigma, das suas correlações e das suas consequências e analisámos os instrumentos psicométricos utilizados para estudar experiências pessoais de estigma. Revimos os principais estudos de investigação sobre estigma em Portugal. Revimos, igualmente, os estudos relevantes utilizando o “Consumer Experiences of Stigma Questionnaire” (CESQ) e as propriedades psicométricas já documentadas. O nosso estudo teve como objetivos: explorar as experiências de estigma numa amostra portuguesa de pessoas com perturbação mental grave e contribuir para a documentação das propriedades psicométricas do “Consumer Experiences of Stigma Questionnaire” e para a validação da sua versão portuguesa. Fizemos um estudo transversal, descritivo e analítico, recolhemos dados sociodemográficos e clínicos e medimos as experiências de estigma e o funcionamento global. A frequência das respostas da secção de estigma foi semelhante à dos restantes estudos utilizando a CESQ. A frequência das respostas na secção de discriminação foi ligeiramente inferior à reportada noutros estudos. Verificámos a existência de uma associação entre a pontuação da subescala de discriminação, o sexo masculino e o facto de se viver na comunidade. A pontuação da subescala de discriminação está também correlacionada de forma positiva com o funcionamento global. Os alfas de Cronbach para a CESQ e para as suas subescalas foram considerados bons. Os coeficientes de correlação intraclasse foram igualmente considerados igualmente bons. Utilizando técnicas de análise fatorial, verificámos que a maior parte dos itens da CESQ se enquadrava em dois fatores, correspondendo sensivelmente às subescalas definidas previamente. Concluímos que o presente estudo explorou com sucesso a questão do estigma em Portugal, contribuindo em simultâneo para a validação do “Consumer Experiences of Stigma Questionnaire.--------------ABSTRACT: We reviewed the evolution of concept of stigma, its correlates and consequences, and analysed psychometric instruments that were used to study personal experiences of stigma. We provided an insight over research of stigma in Portugal. We reviewed relevant studies that use Consumer Experiences of Stigma Questionnaire and documented psychometric properties of this instrument. Our study aimed both to explore experiences of stigma in a Portuguese sample of people with severe mental illness and to contribute to the assessment of the psychometric properties of Consumer Experiences of Stigma Questionnaire and to the validation of its Portuguese translation. We performed a cross sectional descriptive and analytic study, collected socio-demographic data and measured experiences of stigma and global functioning. Frequency of responses regarding stigma section of CESQ matched previous studies using that scale. Frequency of responses in discrimination section was slightly lower than previously reported studies. We found an association between the discrimination score of CESQ and both male gender and living in the community. The discrimination score also positively correlated with global functioning. Cronbach alphas for CESQ and its subscales were good. Intraclass correlation coefficients for CESQ and stigma subscale were also good. Using factor analysis we found most of the items in CESQ would fit 2 factors, grossly corresponding to the previously defined subscales. We conclude that this study successfully explored stigma in Portugal, contributing in simultaneous to the validation of Consumer Experiences Questionnaire.

Validation of a case definition for leptospirosis diagnosis in patients with acute severe febrile disease admitted in reference hospitals at the State of Pernambuco, Brazil

INTRODUCTION: Leptospirosis is often mistaken for other acute febrile illnesses because of its nonspecific presentation. Bacteriologic, serologic, and molecular methods have several limitations for early diagnosis: technical complexity, low availability, low sensitivity in early disease, or high cost. This study aimed to validate a case definition, based on simple clinical and laboratory tests, that is intended for bedside diagnosis of leptospirosis among hospitalized patients. METHODS: Adult patients, admitted to two reference hospitals in Recife, Brazil, with a febrile illness of less than 21 days and with a clinical suspicion of leptospirosis, were included to test a case definition comprising ten clinical and laboratory criteria. Leptospirosis was confirmed or excluded by a composite reference standard (microscopic agglutination test, ELISA, and blood culture). Test properties were determined for each cutoff number of the criteria from the case definition. RESULTS: Ninety seven patients were included; 75 had confirmed leptospirosis and 22 did not. Mean number of criteria from the case definition that were fulfilled was 7.8±1.2 for confirmed leptospirosis and 5.9±1.5 for non-leptospirosis patients (p<0.0001). Best sensitivity (85.3%) and specificity (68.2%) combination was found with a cutoff of 7 or more criteria, reaching positive and negative predictive values of 90.1% and 57.7%, respectively; accuracy was 81.4%. CONCLUSIONS: The case definition, for a cutoff of at least 7 criteria, reached average sensitivity and specificity, but with a high positive predictive value. Its simplicity and low cost make it useful for rapid bedside leptospirosis diagnosis in Brazilian hospitalized patients with acute severe febrile disease.

Fx swaps and outright forward validation

UNL - NSBE

Development and validation of gold nanoprobes for human SNP detection towards commercial application

Conventional molecular techniques for detection and characterization of relevant nucleic acid (i.e. DNA) sequences are, nowadays, cumbersome, expensive and with reduced portability. The main objective of this dissertation consisted in the optimization and validation of a fast and low-cost colorimetric nanodiagnostic methodology for the detection of single nucleotide polymorphisms (SNPs). This was done considering SNPs associated to obesity of commercial interest for STAB VIDA, and subsequent evaluation of other clinically relevant targets. Also, integration of this methodology into a microfluidic platform envisaging portability and application on points-of-care (POC) was achieved. To warrant success in pursuing these objectives, the experimental work was divided in four sections: i) genetic association of SNPs to obesity in the Portuguese population; ii) optimization and validation of the non-cross-linking approach for complete genotype characterization of these SNPs; iii) incorporation into a microfluidic platform; and iv) translation to other relevant commercial targets. FTO dbSNP rs#:9939609 carriers had higher body mass index (BMI), total body fat mass, waist perimeter and 2.5 times higher risk to obesity. AuNPs functionalized with thiolated oligonucleotides (Au-nanoprobes) were used via the non-cross-linking to validate a diagnostics approach against the gold standard technique - Sanger Sequencing - with high levels of sensitivity (87.50%) and specificity (91.67%). A proof-of-concept POC microfluidic device was assembled towards incorporation of the molecular detection strategy. In conclusion a successful framework was developed and validated for the detection of SNPs with commercial interest for STAB VIDA, towards future translation into a POC device.

Simulation of humidity fields in concrete: experimental validation and parameter estimation

The moisture content in concrete structures has an important influence in their behavior and performance. Several vali-dated numerical approaches adopt the governing equation for relative humidity fields proposed in Model Code 1990/2010. Nevertheless there is no integrative study which addresses the choice of parameters for the simulation of the humidity diffusion phenomenon, particularly in concern to the range of parameters forwarded by Model Code 1990/2010. A software based on a Finite Difference Method Algorithm (1D and axisymmetric cases) is used to perform sensitivity analyses on the main parameters in a normal strength concrete. Then, based on the conclusions of the sensi-tivity analyses, experimental results from nine different concrete compositions are analyzed. The software is used to identify the main material parameters that better fit the experimental data. In general, the model was able to satisfactory fit the experimental results and new correlations were proposed, particularly focusing on the boundary transfer coeffi-cient.

Towards automated test and validation of SIP solutions

IP networks are currently the major communication infrastructure used by an increasing number of applications and heterogeneous services, including voice services. In this context, the Session Initiation Protocol (SIP) is a signaling protocol widely used for controlling multimedia communication sessions such as voice or video calls over IP networks, thus performing vital functions in an extensive set of public and enter- prise solutions. However, the SIP protocol dissemination also entails some challenges, such as the complexity associated with the testing/validation processes of IMS/SIP networks. As a consequence, manual IMS/SIP testing solutions are inherently costly and time consuming tasks, being crucial to develop automated approaches in this specific area. In this perspective, this article presents an experimental approach for automated testing/validation of SIP scenarios in IMS networks. For that purpose, an automation framework is proposed allowing to replicate the configuration of SIP equipment from the pro- duction network and submit such equipment to a battery of tests in the testing network. The proposed solution allows to drastically reduce the test and validation times when compared with traditional manual approaches, also allowing to enhance testing reliability and coverage. The automation framework comprises of some freely available tools which are conveniently integrated with other specific modules implemented within the context of this work. In order to illustrate the advantages of the proposed automated framework, a real case study taken from a PT Inovação customer is presented comparing the time required to perform a manual SIP testing approach with the one time required when using the proposed auto- mated framework. The presented results clearly corroborate the advantages of using the presented framework.

A spectrum-driven damage Identification technique : application and validation through the numerical simulation of the Z24 Bridge

The present paper focuses on a damage identification method based on the use of the second order spectral properties of the nodal response processes. The explicit dependence on the frequency content of the outputs power spectral densities makes them suitable for damage detection and localization. The well-known case study of the Z24 Bridge in Switzerland is chosen to apply and further investigate this technique with the aim of validating its reliability. Numerical simulations of the dynamic response of the structure subjected to different types of excitation are carried out to assess the variability of the spectrum-driven method with respect to both type and position of the excitation sources. The simulated data obtained from random vibrations, impulse, ramp and shaking forces, allowed to build the power spectrum matrix from which the main eigenparameters of reference and damage scenarios are extracted. Afterwards, complex eigenvectors and real eigenvalues are properly weighed and combined and a damage index based on the difference between spectral modes is computed to pinpoint the damage. Finally, a group of vibration-based damage identification methods are selected from the literature to compare the results obtained and to evaluate the performance of the spectral index.

Design and validation of a biomechanical bioreactor for cartilage tissue culture

Specific tissues, such as cartilage undergo mechanical solicitation under their normal performance in human body. In this sense, it seems necessary that proper tissue engineering strategies of these tissues should incorporate mechanical solicitations during cell culture, in order to properly evaluate the influence of the mechanical stimulus. This work reports on a user-friendly bioreactor suitable for applying controlled mechanical stimulation - amplitude and frequency - to three dimensional scaffolds. Its design and main components are described, as well as its operation characteristics. The modular design allows easy cleaning and operating under laminar hood. Different protocols for the sterilization of the hermetic enclosure are tested and ensure lack of observable contaminations, complying with the requirements to be used for cell culture. The cell viability study was performed with KUM5 cells.

Validation of a method to measure light distortion surrounding a source of glare

Our objective was to validate a new device dedicated to measure the light disturbances surrounding bright sources of light under different sources of potential variability. Twenty subjects were involved in the study. Light distortion was measured using an experimental prototype (light distortion analyzer, CEORLab, University of Minho, Portugal) comprising twenty-four LED arrays panel at 2 m. Sources of variability included: intrasession and intersession repeated measures, pupil size (3 versus 6 mm), defocus (þ0.50) correction for the working distance, angular resolution (15 deg versus 30 deg), temporal stimuli presentation, and pupil size. Size, shape, location, and irregularity parameters have been obtained. At a low speed of presentation of the stimuli, changes in angular resolution did not have an effect on the results of the parameters measured. Results did not change with pupil size. Intensity of the central glare source significantly influenced the outcomes. Examination time was reduced by 30% when a 30 deg angular resolution was explored instead of 15 deg. Measurements were fast and repeatable under the same experimental conditions. Size and shape parameters showed the highest consistency, whereas location and irregularity parameters showed lower consistency. The system was sensitive to changes in the intensity of the central glare source but not to pupil changes in this sample of healthy subjects.

Implementation and validation of a strain rate dependent anisotropic continuum model for masonry

A newly developed strain rate dependent anisotropic continuum model is proposed for impact and blast applications in masonry. The present model adopted the usual approach of considering different yield criteria in tension and compression. The analysis of unreinforced block work masonry walls subjected to impact is carried out to validate the capability of the model. Comparison of the numerical predictions and test data revealed good agreement. Next, a parametric study is conducted to evaluate the influence of the tensile strengths along the three orthogonal directions and of the wall thickness on the global behavior of masonry walls.