17 research outputs found

    Tuning thermal, morphological, and physicochemical properties of Thermoplastic Polyurethanes (TPUs) by the 1,4-butanediol (BDO)/dipropylene glycol (DPG) ratio

    Get PDF
    Thermoplastic polyurethanes (TPUs) are versatile polymers presenting a broad range of properties as a result of their countless combination of raw materials—in essence, isocyanates, polyols, and chain extenders. This study highlights the effect of two different chain extenders and their combination on the structure–property relationships of TPUs synthesized by reactive extrusion. The TPUs were obtained from 4,4-diphenylmethane diisocyanate (MDI), polyester diols, and the chain extenders 1,4-butanediol (BDO) and dipropylene glycol (DPG). The BDO/DPG ratios studied were 100/0, 75/25, 50/50, 25/75, and 0/100 wt.%. The TPUs were characterized by size exclusion chromatography (SEC), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), UV–vis spectroscopy, and physical-mechanical properties. The results indicate that DPG promotes compatibility between rigid (HS) and flexible (SS) segments of TPUs. Consequently, increasing DPG content (>75 wt.%) reduced the organization of the rigid segments and the degree of phase separation, increasing the polydispersity of the interdomain distance and the transparency in the UV–visible spectrum of the TPUs. Furthermore, increasing DPG content also reduced the amount of hydrogen bonds present in the rigid phase, reducing or extinguishing its glass transition temperature (TgHS) and melting temperature (Tm), and increasing the glass transition temperature of the flexible phase (TgSS). Therefore, increasing DPG content leads to a deterioration in mechanical properties and hydrolysis resistance

    Advantages of treating sponge-gourd waste by mechanical refining on the properties of fiber-based poly(butylene adipate-co-terephthalate)/polylactide biocomposites

    Get PDF
    Abstract This study compares the morphology, thermal, and dynamic-mechanical properties of composites based on polybutylene adipate terephthalate/polylactide biocomposites with sponge gourd waste treated code as R, and non-treated sponge gourd, coded as NR, by mechanical disc refining after milled process. Extrusion followed by compression molding was used to produce biocomposites with fiber contents of 0, 2.5, 5, 10, and 15% wt/wt for R and NR sponge gourd fibers. Scanning electron microscopy analysis reveals that NR has the morphology of a rigid tubular shape, whereas R is a thinner, twisted, and fibrillated fiber. Regardless of the type of sponge gourd fiber used, the thermal stability of the composite decreases as the sponge gourd content increases. At 25°C, the biocomposite with 10%wt/wt R fiber has the highest storage modulus value. The comparison of Tangent peak values reveals that the presence of sponge gourd fibers reduces the energy dissipation of the biocomposites. The analysis of the loss modulus at 25°C reveals that R fiber contributes more to the reduction of energy dissipation of the biocomposites than NR. Furthermore, the Cole-Cole plot shows that R and NR fibers are dispersed and do not significantly change the homogeneity of the biopolymer systems

    Universality of Strength of Yukawa Couplings, Quark Singlets and Strength of CP Violation

    Full text link
    We analyse the strength of CP violation in an extension of the standard model with an extra Q=1/3Q=-1/3 vector-like singlet quark, in the framework of the hypothesis of universality of strength of Yukawa couplings connecting standard quarks. We show that the correct pattern of quark masses and mixing can be obtained, including the observed strength of CP violation.Comment: 9 pages, no figure

    Intervenções fisioterapêuticas na distrofia muscular de duchenne: revisão de literatura / Physiotherapeutic interventions in duchenne muscular dystrophy: literature review

    Get PDF
    Introdução: A distrofia muscular de duchenne é uma doença genética que causa fraqueza muscular progressiva e leva à paralisia total e à morte súbita nos últimos anos da adolescência ou em adultos jovens. Por volta dos cinco anos de idade, a criança começa a apresentar dificuldade de correr ou saltar, a manobra de Gowers ou manobra do levantar miopático,  é um sinal médico que indica a fraqueza dos músculos proximais, especificamente aqueles do membro inferior, devido à atrofia muscular evidente. A hidroterapia é um recurso que vem crescendo no Brasil e começa a ser aceito como opção de tratamento para Distrofia Muscular Progressivas devido as propriedades físicas da água e a movimentação voluntaria. Objetivo: Esta pesquisa tem como objetivo geral verificar o papel do fisioterapeuta e suas condutas nos pacientes com distrofia muscular de duchenne, fazendo uma análise criteriosa dos protocolos de tratamento que possuem embasamento cientifico. Metodologia: O presente artigo tem como fundamento um levantamento bibliográfico realizado nas principais bases de dados eletrônicas Scielo, Pubmed, foram utilizados um total de 11 artigos. Optou-se por incluir estudos com grande amostragem para verificar seus impactos e quais intervenções fisioterapêuticas na distrofia muscular de duchenne. Resultados: Os achados remetentes aos 11 artigos selecionados para o trabalho em questão, concluiu que a Fisioterapia obteve-se um retardo da doença, e prevenção de complicações secundárias. Conclusão: Diante do presente estudo, se conclui que é fundamental a importância do fisioterapeuta na vida do paciente com DMD, pois retarda a evolução da doença e traz mais qualidade de vida para o paciente. 

    Asthma in an Urban Population in Portugal: A prevalence study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The prevalence and incidence of asthma are believed to be increasing but research on the true incidence, prevalence and mortality from asthma has met methodological obstacles since it has been difficult to define and diagnose asthma in epidemiological terms. New and widely accepted diagnostic criteria for asthma present opportunities for progress in this field. Studies conducted in Portugal have estimated the disease prevalence between 3% and 15%. Available epidemiological data present a significant variability due to methodological obstacles.</p> <p>Aim</p> <p>To estimate the true prevalence of asthma by gender and age groups in the population of the area covered by one urban Health Centre in Portugal.</p> <p>Method</p> <p>An observational study was conducted between February and July 2009 at the Horizonte Family Health Unit in Matosinhos, Portugal. A random sample of 590 patients, stratified by age and gender was obtained from the practice database of registered patients. Data was collected using a patient questionnaire based on respiratory symptoms and the physician's best knowledge of the patient's asthma status. The prevalence of asthma was calculated by age and gender.</p> <p>Results</p> <p>Data were obtained from 576 patients (97.6% response rate). The mean age for patients with asthma was 27.0 years (95% CI: 20.95 to 33.16). This was lower than the mean age for non-asthmatics but the difference was not statistically significant. Asthma was diagnosed in 59 persons giving a prevalence of 10.24% (95% CI: 8.16 to 12.32). There was no statistically significant difference in the prevalence of asthma by gender.</p> <p>Conclusion</p> <p>The prevalence of asthma found in the present study was higher than that found in some studies, though lower than that found in other studies. Further studies in other regions of Portugal are required to confirm these findings.</p

    Relatório final de estágio realizado na Escola Secundária de S. João do Estoril no ano lectivo 2009-2010

    No full text
    Mestrado em Ensino da Educação Física nos Ensinos Básico e SecundárioEste documento consiste no relatório do estágio pedagógico, realizado no ano lectivo de 2009/10, na Escola Secundária de S. João do Estoril. Na parte inicial é efectuada uma caracterização do contexto em que se realizou o estágio. Essa contextualização é realizada não só através da análise demográfica da Escola, mas também através da análise de alguns documentos internos, com o objectivo de melhor compreender o seu funcionamento enquanto Organização Escolar. Posteriormente, é realizada uma análise da formação realizada em cada uma das áreas definidas pelo Guia de Estágio. Esta análise da formação é efectuada através das actividades desenvolvidas, sendo que se encontra sub-dividida em actividades desenvolvidas no trabalho com a turma e no trabalho na escola. Esta análise tem por objectivo aferir quais as competências desenvolvidas ao longo do processo de estágio e quais aquelas que necessitam de maior investimento no futuro, dotando assim o estágio de uma perspectiva projectiva em relação à minha formação. Esta análise é efectuada com referência não só ao conhecimento empírico desenvolvido ao longo do processo de estágio, mas também com recurso a um referencial teórico. No final serão apresentadas as conclusões do relatório, bem como a bibliografia consultada e os anexos ao relatório

    Characterization of human urinary calculi from bladder and kidney by X Ray diffraction and microtomography

    No full text
    Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorA urolitíase é um problema de escala mundial, que ocorre em todas as regiões, culturas e grupos raciais. A incidência desta doença vem aumentando ao redor do mundo e dados mostram que no Brasil estima-se que são afetados 5% da população com uma taxa de recorrência de 2,5%. Conhecer a composição mineral e estrutura interna dos cálculos é um passo importante para tentar entender melhor a fisiopatologia desta doença. Quatro cálculos urinários infecciosos, íntegros de grande volume (diâmetro maior que 20 mm), sendo dois provenientes da bexiga e dois de rins, obtidos cirurgicamente no setor de urologia do Hospital Universitário Pedro Ernesto (HUPE/UERJ) foram analisados usando microtomografia (&#956;CT) e difração de raios X por policristais (DRXP). As imagens microtomográficas foram obtidas usando tubo de raios X microfoco na estação TomoLab e radiação síncrotron (SR-&#956;CT) na linha de Física Médica, ambos no Laboratório Síncrotron Elettra, Trieste, Itália. As medidas de DRXP foram realizadas na linha de Difração de Raios X do Laboratório Nacional de luz Síncrotron, Campinas, Brasil. Para os cálculos de bexiga foram encontradas quatro fases cristalinas: estruvita (STV), oxalato mono (COM) e dihidratado (COD) e hidroxiapatita (HAp). Nos cálculos renais foram encontrados STV e HAp, sendo predominante a primeira fase cristalina. A quantidade de material amorfo (não-cristalino) foi maior que 60% da composição das amostras. A técnica convencional utilizada foi eficaz para análise dos cálculos urinários inteiros e possibilitou a visualização de estruturas internas sem interferência de procedimentos prévios de preparação da amostra. As análises de DRXP com fonte síncrotron aliadas ao método Rietveld foram determinantes para identificação e quantificação dos minerais presentes nas varias camadas das amostras. Pode-se constatar a complementaridade entre a &#956;CT e a DRXP para caracterização microestrutural e mineralógica de cálculos urinários humanos.Urolithiasis is a worldwide problem that afflicts all regions, cultures and ethnics groups. The incidence is increasing around the world and related data about Brazil estimate that affect 5% population with 2.5% recurrence rate. Knowledge of the quantitative mineralogy of urinary calculi is of fundamental importance for optimization of nephrolithiasis therapy and to prevent potential risk of recurrence. The urinary stones used in the present study were made available to us via normal surgery from patients admitted to the Hospital Universitário Pedro Ernesto (HUPE/UERJ). Structural and microstructural characterizations of four urinary calculi samples (RJ100, RJ101, RJ102 e RJ104) were determined by means of X-ray microtomography and powder diffraction. Conventional (&#956;CT) and synchrotron radiation microtomography (SR-&#956;CT) experiments were performed at the TOMOLAB station and SYRMEP (SYnchrotron Radiation on MEdical Physics) beamline, both at the Elettra Synchrotron Light Laboratory in Trieste (Italy), respectively. Synchrotron X-ray powder diffraction (XRPD) data were collected at the X-ray powder diffraction beamline of the National Synchrotron Light Laboratory (LNLS) in Campinas, Brazil. For the bladder stones, RJ100 and RJ104, the identified phases were struvite (STV), calcium oxalate monohydrate (COM) and dihydrate (COD) and calcium hydroxyapatite (HAp). The kidney stones RJ101 and RJ102 can be considered pure struvite stones. Moreover, the Rietveld refinement indicates the presence of more than 60 wt% of amorphous phase of all samples. The use of &#956;CT scanning technology not only improves knowledge of internal structures of intact urinary calculi, but also allowed us to investigate efficiently specimens that run a particular risk of deformation or destruction from conventional preparation. Synchrotron X-ray powder profile-fitting structure refinement using the Rietveld method has proved to be a powerful tool in identifying and estimating the quantitative crystalline phase abundances present in the samples. This work demonstrated the capabilities of a combination of&#956;CT and XRP analyses for structural and microstructural characterizations of human urinary calculi samples. Moreover, the XRD data demonstrate that STV is the major constituent phase in all samples, which seems to be a tendency in Rio de Janeiro population. Clearly, there is a need for more studies on stone disease from Rio de Janeiro in order to isolate the fundamental reasons for the observed features of the kidney stones distribution

    Assessing Anatomical Changes in Male Reproductive Organs in Response to Larval Crowding Using Micro-computed Tomography Imaging

    No full text
    Abstract Ecological conditions shape (adaptive) responses at the molecular, anatomical, and behavioral levels. Understanding these responses is key to predict the outcomes of intra- and inter-specific competitions and the evolutionary trajectory of populations. Recent technological advances have enabled large-scale molecular (e.g., RNAseq) and behavioral (e.g., computer vision) studies, but the study of anatomical responses to ecological conditions has lagged behind. Here, we highlight the role of X-ray micro-computed tomography (micro-CT) in generating in vivo and ex vivo 3D imaging of anatomical structures, which can enable insights into adaptive anatomical responses to ecological environments. To demonstrate the application of this method, we manipulated the larval density of Drosophila melanogaster Meigen flies and applied micro-CT to investigate the anatomical responses of the male reproductive organs to varying intraspecific competition levels during development. Our data is suggestive of two classes of anatomical responses which broadly agree with sexual selection theory: increasing larval density led to testes and ejaculatory duct to be overall larger (in volume), while the volume of accessory glands and, to a lesser extent, ejaculatory duct decreased. These two distinct classes of anatomical responses might reflect shared developmental regulation of the structures of the male reproductive system. Overall, we show that micro-CT can be an important tool to advance the study of anatomical (adaptive) responses to ecological environments

    Smartphone-based outlier detection: a complex event processing approach for driving behavior detection

    No full text
    Abstract The majority of fatal car crashes are caused by reckless driving. With the sophistication of vehicle instrumentation, reckless maneuvers, such as abrupt turns, acceleration, and deceleration, can now be accurately detected by analyzing data related to the driver-vehicle interactions. Such analysis usually requires very specific in-vehicle hardware and infrastructure sensors (e.g. loop detectors and radars), which can be costly. Hence, in this paper, we investigated if off-the-shelf smartphones can be used to online detect and classify the driver’s behavior in near real-time. To do so, we first modeled and performed an intrinsic evaluation to assess the performance of three outlier detection algorithms formulated as a data stream processing network which receives as input and processes data streams of smartphone and vehicle sensors. Next, we implemented a novel scoring mechanism based on online outlier detection to quantitatively evaluate drivers’ maneuvers as either cautious or reckless. Thus, we adapted a data mining mechanism which takes into account a sensor’s data rates and power to determine driver behavior in the scoring process. Finally, as the intrinsic evaluation does not necessarily reveal how well an algorithm will perform in a real-world scenario, we evaluated the algorithm that achieved the best result in a real-world case study to assess drivers’ driving behavior. Our results indicate that the algorithm performs quickly and accurately; the algorithm classifies driver behavior with 95.45% accuracy. Moreover, such results are obtained within 100 milliseconds of processing time on average
    corecore