399 research outputs found

    Félix Candela. En memoria (1910-1997). Del cascarón de hormigón a las estructuras ligeras del s. XXI

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    January 27th of this year, 2010, was the centenary of the birth of a famous architect of Spanish origin, Félix Candela, one of the most prominent players in modern architecture’s thin shell adventure. His international fame was based on precisely that, the construction of over 800 thin concrete shells characterized not only by their rationality and optimal strength, but also by their striking sculptural beauty. Architects such as Frei Otto, Ove Arup and David Billington justifiably called his work“structural art”. In addition analyzing Félix Candela’s contribution to modern architecture, the present article explores new lightweight structures as the ongoing pursuit of the optimization of structural form with different materials and technologies. That pursuit, both past and present, constitutes the focus of attention of the International Association for Structural Shells, IASS, founded by Eduardo Torroja in 1959 and fully operational today.El 27 de enero de 2010 se cumplió el centenario del nacimiento de célebre arquitecto de origen español Félix Candela, uno de los más destacados protagonistas de la Aventura Laminar de la Arquitectura Moderna. Su fama internacional la adquirió a través de la construcción de más de 800 cascarones de hormigón armado dotados, no sólo de una racional y óptima forma resistente, sino también de una impactante y escultural belleza. No en vano, Frei Otto, Ove Arup y David Billington han descrito su obra como un “Arte Estructural”. Al hilo del análisis de las aportaciones realizadas por Félix Candela, el presente artículo analiza también nuevas estructuras ligeras, como continuidad histórica de esa racional búsqueda de la optimización de la forma resistente con diferentes materiales y tecnologías. Evolución y destino contemplado por la Internacional Association for Structural Shells IASS, fundada por Eduardo Torroja en 1959 y que hoy continúa en plena actividad

    A multi-reflection time-of-flight mass spectrometer for the offline ion source of the PUMA experiment

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    The antiProton Unstable Matter Annihilation experiment (PUMA) at CERN aims at investigating the nucleon composition in the matter density tail of radioactive as well as stable isotopes by use of low-energy antiproton-nucleon annihilation processes. For this purpose, antiprotons provided by the Extra Low ENergy Antiproton (ELENA) facility will be trapped together with the ions of interest. While exotic ions will be obtained by the Isotope mass Separator On-Line DEvice (ISOLDE), stable ions will be delivered from an offline ion source setup designed for this purpose. This allows the proposed technique to be applied to a variety of stable nuclei and for reference measurements. For beam purification, the ion source setup includes a multi-reflection time-of-flight mass spectrometer (MR-ToF MS). Supported by SIMION simulations, an earlier MR-ToF MS design has been modified to meet the requirements of PUMA. During commissioning of the new MR-ToF device with Ar+^+ ions, mass resolving powers in excess of 50,000 have been obtained after 150 revolutions, limited by the chopping of the continuous beam from an electron impact ionisation source

    Overexpression and knock-down studies highlight that a disintegrin and metalloproteinase 28 controls proliferation and migration in human prostate cancer

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    Prostate cancer is one of the most prevalent cancers inmen. It is critical to identify and characterize oncogenes that drive the pathogenesis of human prostate cancer. The current study builds upon previous research showing that a disintegrin and metalloproteinase (ADAM)28 is involved in the pathogenesis of numerous cancers. Our novel study used overexpression, pharmacological, and molecular approaches to investigate the biological function of ADAM28 in human prostate cancer cells,with a focus on cell proliferation andmigration. The results of this study provide important insights into the role of metalloproteinases in human prostate cancer. The expression of ADAM28 protein levels was assessed within human prostate tumors and normal adjacent tissue by immunohistochemistry. Immunocytochemistry and western blotting were used to assess ADAM28 protein expression in human prostate cancer cell lines. Functional assays were conducted to assess proliferation and migration in human prostate cancer cells in which ADAM28 protein expression or activity had been altered by overexpression, pharmacological inhibition, or by siRNA gene knockdown. The membrane bound ADAM28 was increased in human tumor biopsies and prostate cancer cell lines. Pharmacological inhibition of ADAM28 activity and/or knockdown of ADAM28 significantly reduced proliferation and migration of human prostate cancer cells, while overexpression of ADAM28 significantly increased proliferation and migration. ADAM28 is overexpressed in primary human prostate tumor biopsies, and it promotes human prostate cancer cell proliferation and migration. This study supports the notion that inhibition of ADAM28 may be a potential novel therapeutic strategy for human prostate cancer. Abbreviations: ADAM = a disintegrin and metalloproteinase, CTGF = connective tissue growth factor, DHT = dihydrotestosterone, IGF = insulin-like growth factor, IGFBP-3 = IGF binding protein-3, IL-6 = interleukin 6, RPMI = Roswell Park Memorial Institute, VEGF = vascular endothelial growth factor, VWF = von Willebrand factor

    Design of floor structures for human induced vibrations

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    In recent years, the introduction of new structural materials and innovative construction processes, associated to architectural and space arrangement requirements, in multi-storey buildings construction have produced significantly more flexible floor structural systems. The design of these floor systems is usually controlled by serviceability criteria, deflections or vibrations. Recognizing a gap in the design codes, this report gives a procedure for the determination and assessment of floor response for human induced vibrations. First, the proposed procedure is presented, giving particular attention to the human induced loading characterization, dynamic properties and the comfort criteria for the verification of floor structural systems. Design charts are derived. Finally, it is presented a guidance manual to use the simplified procedure proposed for the design of building floors for human induced vibrations. Two worked examples of the proposed design procedure are given, namely a filigree slab with ACB-composite beams and a composite slab with steel beams.JRC.DG.G.5-European laboratory for structural assessmen

    Ultra-low-dose quadruple combination blood pressure lowering therapy in patients with hypertension: The QUARTET randomized controlled trial protocol.

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    High blood pressure is the leading cause of preventable morbidity and mortality globally. Many patients remain on single-drug treatment with poor control although guidelines recognize that most require combination therapy for blood pressure control. Our hypothesis is that a single-pill combination of four blood pressure- lowering agents each at a quarter dose may provide a simple, safe and effective blood pressure lowering solution which may also improve long term-adherence. The QUARTET (Quadruple UltrA-low-dose tReaTment for hypErTension) double-blind, active controlled, randomized clinical trial will examine whether ultra-low-dose quadruple combination therapy is more effective than guideline recommended standard care, in lowering blood pressure. QUARTET will enroll 650 participants with high blood pressure, either on no treatment or on monotherapy. Participants will be randomized 1:1 and allocated to intervention therapy of a single pill (quadpill) containing irbesartan 37.5 mg, amlodipine 1.25 mg, indapamide 0.625 mg and bisoprolol 2.5 mg or to control therapy of a single identical appearing pill containing irbesartan 150 mg. In both arms step up therapy of open-label amlodipine 5mg will be provided if BP is >140/90 at 6weeks. The primary outcome is the difference between groups in the change from baseline in mean unattended automated office systolic blood pressure at 12weeks follow-up. The primary outcome and some secondary outcomes will be assessed at 12weeks, there is an optional 12months extension phase to assess longer term efficacy and tolerability. Our secondary aims are to assess if this approach is safe, has fewer adverse effects and better tolerability compared to standard care control. QUARTET will therefore provide evidence for the effectiveness and safety of a new paradigm in the management of high blood pressure

    Provision of non-invasive coronary and carotid vascular imaging results on changes in diet and physical activity in asymptomatic adults: A scoping review

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    Background: Although a healthy diet and physical activity have been shown to prevent or delay cardiovascular disease (CVD) hospitalizations and deaths, most adults do not meet current guidelines. Provision of coronary artery calcification (CAC) and carotid ultrasound (CUS) imaging results may motivate beneficial lifestyle changes. We scoped the existing literature for studies providing non-invasive vascular imaging results and reporting diet, physical activity, and/or anthropometric measures to identify knowledge gaps and opportunities for further research. Methods: A systematic search was performed across three electronic databases, in line with PRISMA ScR guidelines and Arksey and O\u27Malley\u27s scoping review framework. Results: Twenty studies (thirteen observational and seven randomized controlled trials) examining the impact of provision of CAC/CUS imaging results on diet and/or physical activity behaviors were included. Nearly half the studies did not clearly state whether participants received dietary and physical activity advice along with vascular imaging results, and these were secondary outcomes in most studies, with data assessment and reporting being inconsistent. Conclusion: Well-designed clinical trials with consistent and clear messaging based on detailed subjective and objective measures of diet and physical activity are needed to determine whether this approach may stimulate long-term dietary and physical activity change

    An overview of historical and contemporary concrete shells, their construction and factors in their general disappearance

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    Only through understanding why concrete shells’ loss in popularity over the course of modern history can designers be equipped with the skills to create and apply this type of construction. Through modifications to design processes, construction stages, material understanding and relevant formwork improvements will architects and designers be able to meet the demands of the 21st century and beyond. To understand why concrete shells are no longer commonly built is to understand its construction process. An amorphous material, the fundamental relationship between formwork and the resultant concrete shell needs to be raised, appreciated, understood and analyzed for a holistic understanding of concrete shells. Through understanding this, issues and factors affecting concrete shells can be tackled and designed out in reviving this type of structures because they can be efficient in structural performance, economical in cost and provide high aesthetic value. This paper discusses concrete shells as an architectural solution by asking the question to what constituted their popularity and factors that led to their demise in the modern age of technological advancement, construction process and environmental concerns. This paper presents a cultural perspective and an overview of seminal, historical and contemporary concrete shells so as to bring about a renaissance of such structures in our built environment once again because of all the benefits it can offer.</p

    Sympatho-renal axis in chronic disease

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    Essential hypertension, insulin resistance, heart failure, congestion, diuretic resistance, and functional renal disease are all characterized by excessive central sympathetic drive. The contribution of the kidney’s somatic afferent nerves, as an underlying cause of elevated central sympathetic drive, and the consequences of excessive efferent sympathetic signals to the kidney itself, as well as other organs, identify the renal sympathetic nerves as a uniquely logical therapeutic target for diseases linked by excessive central sympathetic drive. Clinical studies of renal denervation in patients with resistant hypertension using an endovascular radiofrequency ablation methodology have exposed the sympathetic link between these conditions. Renal denervation could be expected to simultaneously affect blood pressure, insulin resistance, sleep disorders, congestion in heart failure, cardiorenal syndrome and diuretic resistance. The striking epidemiologic evidence for coexistence of these disorders suggests common causal pathways. Chronic activation of the sympathetic nervous system has been associated with components of the metabolic syndrome, such as blood pressure elevation, obesity, dyslipidemia, and impaired fasting glucose with hyperinsulinemia. Over 50% of patients with essential hypertension are hyperinsulinemic, regardless of whether they are untreated or in a stable program of treatment. Insulin resistance is related to sympathetic drive via a bidirectional mechanism. In this manuscript, we review the data that suggests that selective impairment of renal somatic afferent and sympathetic efferent nerves in patients with resistant hypertension both reduces markers of central sympathetic drive and favorably impacts diseases linked through central sympathetics—insulin resistance, heart failure, congestion, diuretic resistance, and cardiorenal disorders

    Reduction in Basal Nitric Oxide Activity Causes Albuminuria

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    OBJECTIVE-The barrier function of the glomerular filter has been studied for decades. Albuminuria reflects a malfunction of this barrier, and in animals dysfunctional endothelial nitric-oxide (NO) synthase results in albuminuria. We aimed to analyze the importance of NO for the glomerular barrier function in humans. RESEARCH DESIGN AND METHODS-To assess the effect of endothelial dysfunction on albuminuria, we measured the urine albumin-to-creatinine ratio (UACR) both before and after the blockade of NO synthases (NOSs) with systemic infusion of N-G-monomethyl-L-arginine (L-NMMA) in two distinct study populations. In population A, 62 hypertensive patients with type 2 diabetes and, in population B, 22 patients with hypercholesterolemia but without hypertension or type 2 diabetes were examined. All subjects had normal renal function. RESULTS-There was a significant increase in the UACR in response to NOS inhibition with L-NMMA in hypertensive patients with type 2 diabetes (study population A) and in patients with hypercholesterolemia (study population B). Linear regression analyses revealed that the change in mean arterial presssure in response to L-NMMA was not related to the increase in the UACR in response to L-NMMA in either population, even after adjusting for filtration fraction. CONCLUSIONS-NOS inhibition provokes albuminuria that is unrelated to changes in blood pressure. It is noteworthy that this finding was evident in patient groups prone to endothelial dysfunction and albuminuria. Thus, acute deterioration of endothelial function by reducing NO activity causes an increase in albuminuria. Diabetes 60:572-576, 201
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