7,206 research outputs found

    Regime mapping and the role of the intermediate region in wall-coated microreactors

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    Operation of a wall-coated microreactor can occur in several mass transfer-reaction regimes. We define these regimes analytically in several planes of a multi-parametric map, taking into account the different degrees of concentration profile development, as well as the influence of non-unity orders of reaction and reactant inhibition in the kinetic law. It was found that the regions where conversion can be calculated from simplified mass transfer models are not discriminated by common results for entrance-length. We also illustrate the trade-offs that exist across this operating map concerning the catalyst design (costs associated with loading and volume) and overall system performance (evaluated in terms of reactant conversion, flow efficiency and microreactor effectiveness). It is shown that under certain conditions, the existence of moderate mass transfer resistance can be advantageous (even if internal limitations cannot be avoided), clarifying the role of the intermediate transport-reaction region

    Doença Relacionada à IgG4 Apresentando-se como Massa de Mesenterite Esclerosante

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    IgG4 related disease (IgG4 RD) is a newly recognized entity that includes a group of immune-mediated fibro-inflammatory conditions. It can affect a wide range of organs, producing a broad spectrum of presentations. The selection of imaging modality is based on patient symptoms and the organs under evaluation. The diagnosis is based on a combination of radiological findings, serum IgG4 elevation levels, histopathological features, association with other IgG4-related diseases and response to steroids. We report a rare case of an IgG4-related sclerosing mesenteritis in a man who presented with an incidental right lower quadrant mesenteric mass and was unsuccessfully treated with corticoids. Isolated mesentery involvement is a rare presentation of IgG4-related disease and only few cases were reported in literatureinfo:eu-repo/semantics/publishedVersio

    Aromatase Inhibitors in Male Adolescents with Idiopathic Short Stature

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    Introdução: O efeito dos fármacos inibidores da aromatase (IA) na estatura de jovens do sexo masculino com baixa estatura idiopática (BEI) tem vindo a ser estudado desde que foi evidenciado o papel dos estrogénios na paragem do crescimento linear. Os ensaios clínicos aleatorizados, duplamente cegos, de caso-controlo com letrozol indicam impacto positivo na previsão de estatura final em jovens do sexo masculino com BEI, com ou sem atraso constitucional do crescimento e puberdade. Por persistirem aspetos de segurança a requerer melhor estudo, a sua utilização terapêutica continua a ser off label. Objetivos: Tendo em vista a implementação de um ensaio clínico sobre a terapêutica com IA em jovens do sexo masculino com BEI procedeu-se a uma revisão sistemática da literatura, na qual se fundamenta a proposta de protocolo apresentada. Métodos: Pesquisa na base de dados eletrónica Medline de revisões sistemáticas, ensaios clínicos alea-torizados controlados e referências bibliográficas dos artigos seleccionados, publicados entre Janeiro de 2001 e Dezembro de 2012. Conclusões: A terapêutica com um IA de terceira geração (letrozol) poderá ser considerada em jovens do sexo masculino com BEI, altura inferior a pelo menos −2,0 SDS para a idade ou previsão de altura final pelo menos 2,0 SDS abaixo da estatura média parental, desde que já tenha sido iniciada a puberdade e a idade óssea seja inferior a 14 anos. Os principais aspectos de segurança ainda sob discussão na literatura referem-se a potenciais efeitos a nível ósseo. A utilização de medicamentos off-label deve obedecer a critérios estritos de prescrição e seguimento das crianças, de forma a minimizar os riscos e obter resultados fiáveis e comparáveis. Apresenta-se proposta de sistematização de monitorização clínica, imagiológica e laboratorial, bem como critérios de término ou suspensão da mesma

    The best CRISPR/Cas9 versus RNA interference approaches for Arabinogalactan proteins' study

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    Arabinogalactan Proteins (AGPs) are hydroxyproline-rich proteins containing a high proportion of carbohydrates, widely spread in the plant kingdom. AGPs have been suggested to play important roles in plant development processes, especially in sexual plant reproduction. Nevertheless, the functions of a large number of these molecules, remains to be discovered. In this review, we discuss two revolutionary genetic techniques that are able to decode the roles of these glycoproteins in an easy and efficient way. The RNA interference is a frequently technique used in plant biology that promotes genes silencing. The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated protein 9 (CRISPR/Cas9), emerged a few years ago as a revolutionary genome-editing technique that has allowed null mutants to be obtained in a wide variety of organisms, including plants. The two techniques have some differences between them and depending on the research objective, these may work as advantage or disadvantage. In the present work, we propose the use of the two techniques to obtain AGP mutants easily and quickly, helping to unravel the role of AGPs, surely a great asset for the future

    Outcomes of Single-Operator Cholangioscopy-Guided Lithotripsy in Patients with Difficult Biliary and Pancreatic Stones

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    BACKGROUND AND AIMS: Endoscopic retrograde cholangiopancreatography is the preferred strategy for the management of biliary and pancreatic duct stones. However, difficult stones occur, and electrohydraulic (EHL) and laser lithotripsy (LL) have emerged as treatment modalities for ductal clearance. Recently, single-operator cholangioscopy was introduced, permitting the routine use of these techniques. We aimed to evaluate the clinical effectiveness of cholangioscopy-guided lithotripsy using LL or EHL in patients with difficult biliary or pancreatic stones. METHODS: This is a prospective clinical study - conducted at two affiliated university hospitals - of 17 consecutive patients with difficult biliary and pancreatic stones who underwent single-operator cholangioscopy-guided lithotripsy using two techniques: holmium laser lithotripsy (HL) or bipolar EHL. We analyzed complete ductal clearance as well as the impact of the location and number of stones on clinical success and evaluated the efficacy of the two techniques used for cholangioscopy-guided lithotripsy and procedural complications. RESULTS: Twelve patients (70.6%) had stones in the common bile duct/common hepatic duct, 2 patients (17.6%) had a stone in the cystic stump, and 3 patients (17.6%) had stones in the pancreas. Sixteen patients (94.1%) were successfully managed in 1 session, and 1 patient (5.9%) achieved ductal clearance after 3 sessions including EHL, LL, and mechanical lithotripsy. Eleven patients were successfully submitted to HL in 1 session using a single laser fiber. Six patients were treated with EHL: 4 patients achieved ductal clearance in 1 session with a single fiber, 1 patient obtained successful fragmentation in 1 session using two fibers, and 1 patient did not achieve ductal clearance after using two fibers and was successfully treated with a single laser fiber in a subsequent session. Complications were mild and were encountered in 6/17 patients (35.2%), including fever (n = 3), pain (n = 1), and mild pancreatitis (n = 1). Conclusions: Cholangioscopy-guided lithotripsy using LL or EHL in patients with difficult biliary or pancreatic stones is highly effective with transient and minimal complications. There is a clear need to further compare EHL and HL in order to assess their role in the success of cholangioscopy-guided lithotripsy.info:eu-repo/semantics/publishedVersio

    Displasias Ectodérmicas

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    Ectodermal dysplasias are a heterogeneous group of rare inherited disorders. Molecular findings and clarification of cell sig naling processes and ectodermal-mesenchyme interaction enabled the development of a clinical-functional model, which in turn helps to explain clinical signs, with variability in severity, associated non-ectodermal abnormalities and overlap seen in many patients. We herein review the current state of knowledge regarding this distinct entity and illustrate with an elucidative case report. The need for early multidisciplinary intervention is highlighted, and further studies will focus on genetically-target therapeutic approaches.As displasias ectodérmicas representam um grupo heterogéneo de doenças hereditárias raras. Os achados moleculares e o esclarecimento dos processos de sinalização celular e da interação ectoderme-mesênquima permitiram compreender os sinais clínicos. Estes caracterizam-se por gravidade variável, observando-se associação a anomalias não ectodérmicas e sobreposição clínica em muitos pacientes. No presente trabalho resumimos o estado atual do conhecimento sobre as displasias ectodérmicas e apresentamos ainda um relato de caso ilustrativo. Salientamos a necessidade de intervenção multidisciplinar precoce, sendo necessários estudos futuros com enfoque em abordagens terapêuticas geneticamente direcionadas.info:eu-repo/semantics/publishedVersio

    Intrathyroidal Ectopic Thymus: A Case Series

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