946 research outputs found

    Usefulness of QT dispersion in clinical practice

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    The measurement of QT dispersion in the surface electrocardiogram has been proposed as a non invasive method for assessing inhomogeneity of myocardial repolarization and has been linked to an increased risk of arrhythmic cardiac death. Several studies have evaluated the use of QTd in a wide variety of cardiac diseases and have reached conflicting conclusions regarding its clinical significance

    Design of a non-destructive test for validating models of hydrogen migration.

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    High-strength steels, despite their excellent mechanical properties in normal conditions, can be susceptible to hydrogen embrittlement. Due to the service loads or residual stresses, hydrogen migrates within the component and accumulates in the regions where the highest tensile hydrostatic stress occurs. As a consequence, component brittle failure can occur even if the initial or mean hydrogen concentration is lower than the critical value. The availability of models predicting the hydrogen diffusion within the component is a crucial task for the design. Several diffusive models have been presented in the literature and some general-purpose finite element codes have implemented some of them. However, the validation of those models is still an open issue due to the difficulty in performing accurate local measurements of the hydrogen concentration. This study deals with the design of a test potentially able to validate hydrogen migration models. In the test, a four-point bending configuration is applied to a properly shaped hourglass specimen, previously charged with hydrogen, extracted from thin high-strength steel sheets. The specimen geometry and the loading configuration were designed to obtain a central region in which the stress and strain field is uniform in plane and exhibits a quasi-uniform gradient in the thickness direction. As a consequence, it is expected a large enough central region of the specimen in which the Hydrogen can migrate only in the thickness direction during the typical duration of the test. The local hydrogen concentration is evaluated by measuring the flux leaving the tensile surface of the specimen by a solid-state hydrogen sensor

    Processing plants and technologies for a sustainable Mediterranean food chain

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    This book is focused on the challenges to implement sustainability in diverse contexts such as agribusiness, natural resource systems and new technologies. The experiences made by the researchers of the School of Agricultural, Forestry, Food and Environmental Science (SAFE) of the University of Basilicata offer a wide and multidisciplinary approach to the identification and testing of different solutions tailored to the economic, social and environmental characteristics of the region and the surrounding areas. Basilicata’s productive system is mainly based on activities related to the agricultural sector and exploitation of natural resources but it has seen, in recent years, an industrial development driven by the discovery of oil fields. SAFE research took up the challenge posed by market competition to create value through the sustainable use of renewable and non-renewable resources of the territory. Moreover, due to its unique geographical position in the middle of the Mediterranean basin, Basilicata is an excellent “open sky” laboratory for testing sustainable solutions adaptable to other Mediterranean areas. This collection of multidisciplinary case studies and research experiences from SAFE researchers and their scientific partners is a stimulating contribution to the debate on the development of sustainable techniques, methods and applications for the Mediterranean regions

    Advance in Citrus Postharvest Management: Diseases, Cold Storage and Quality Evaluation

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    Citrus is a fruit crop grown in different Mediterranean countries. Generally, harvested fruits are used for fresh consumption or are processed (mainly to produce juices). In this chapter, the authors discuss the state of art on citrus postharvest with a scientific approach, evaluating the current knowledge about the physiology and pathology of citrus fruits and the main causes of deterioration. In addition, the authors explain the main facilities for the cold storage of citrus fruit with particular reference to the rapid-cooling techniques and treatments needed prior to shipment of citrus fruits (refer shipment). In the last part of the chapter, the non-destructive methods for the quality evaluation are presented

    The use of thrombopoietin-receptor agonists (TPO-RAs) in immune thrombocytopenia (ITP): a “real life” retrospective multicenter experience of the Rete Ematologica Pugliese (REP)

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    Immune thrombocytopenia (ITP) is a disease which sees one-third of patients failing first and subsequent therapeutic approaches, including splenectomy. Thrombopoietin-receptor agonists (TPO-RAs) are recommended for adults who relapse after splenectomy or who have contraindications for splenectomy. In this multicenter study, a total of 124 patients were retrospectively evaluated: 55 (44.3 %) were treated by romiplostim and 69 (55.6 %) by eltrombopag. Mean age, number of young patients (<60 years), time from primary diagnosis of ITP to TPO-RA treatment, and previous lines of therapy were similar in both groups. The overall response rate was 80 % (44/55) for romiplostim and 94.2 % (65/69) for eltrombopag; the duration of response and the time to response were similar (p = NS). The response rate to both drugs in non-splenectomized patients was higher than that of splenectomized patients (p < 0.05). The mean duration of response was 30 months for romiplostim and 15 months for eltrombopag, due to later commercialization of eltrombopag. Failure was the most frequent cause of discontinuation. Thrombotic events were the most consistent adverse events and were recorded in 2 and 3 % of patients treated by romiplostim and eltrombopag, respectively. In conclusion, romiplostim and eltrombopag are effective in the majority of patients with chronic ITP who failed several lines of therapy; whether TPO-RAs could substitute splenectomy is under discussion and studies are warranted

    Early and long-term outcomes of carotid endarterectomy in the very elderly: An 18-year single-center study

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    ObjectiveTo evaluate the perioperative (30-day) and long-term outcomes of carotid endarterectomy (CEA) in elderly patients with severe symptomatic and asymptomatic carotid disease. Although the efficacy of CEA in preventing stroke in selected patients has been clearly demonstrated, concern has been expressed about the role of CEA in people over 80 years old.MethodsAn analysis was conducted on a prospectively compiled computerized database of all primary CEAs performed at our institution from 1990 to 2007. Descriptive demographic data, risk factors, surgical details, perioperative strokes and deaths, and other complications were recorded. All patients underwent postoperative duplex ultrasound scanning and clinical follow-up at one, six, and 12 months, and yearly thereafter. Survival analyses were performed using Kaplan-Meier life-tables. Long-term relative survival after CEA was assessed against age- and gender-matched controls.ResultsIn all, 1769 CEAs were performed in 1562 patients, 193 of them (207 CEAs; group I) were ≥ 80 years old and 1371 were younger (1562 CEAs; group II). All CEA procedures were performed with patients under deep general anesthesia with continuous perioperative EEG monitoring for selective shunting. No strokes or deaths occurred in group I, whereas there were 11 perioperative strokes and three deaths in group II (1%). A complete follow-up (median, 5.2 years) was obtained in 185 elderly patients: no late occlusions or restenoses were detected, while the seven-year freedom from stroke and death were 96.6% and 52.4%, respectively. The relative seven-year survival rate was 99.8%.ConclusionsCEA in elderly patients proved safe and effective, with an excellent long-term durability. The long-term relative survival after CEA in elderly patients was better than in an age-and gender-matched population, so the likelihood of living long enough to benefit from CEA is not jeopardized by being very elderly

    A two-component mantle source feeding Mt. Etna magmatism; insights from the geochemistry of primitive magmas.

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    The major elements, trace elements and Sr and Nd isotopes of selected Etnean primitive rocks (b15 ky BP) were studied in order to characterize their mantle source. The noble-gas geochemistry of fluid inclusions in minerals fromthe same lavaswas also investigated. Themajor element compositions ofwhole rocks and minerals showed that these products are among the most primitive atMt. Etna, comprising 6.3–17.5 wt.% MgO. The variable LREE (Light Rare Earth Elements) enrichment relative to MORB (Mid-Ocean Ridge Basalt) (Lan/Ybn = 11–26), togetherwith the patterns of certain trace-element ratios (i.e., Ce/Yb versus Zr/Nb and Th/Y versus La/Yb), can be attributed to varying degrees of melting of a common mantle source. Numerical simulations performed with the MELTS program allowed the melting percentages associated with each product to be estimated. This led us to recalculate the hypothetical parental trace-element content of the Etneanmantle source, whichwas common to all of the investigated rocks. The characteristics of the Sr, Nd and He isotopes confirmed the primitive nature of the rocks,with themost-depleted and primitive lava being that ofMt. Spagnolo (SPA; 143Nd/144Nd = 0.512908 87Sr/ 86Sr = 0.703317–0.703325 and 3He/4He = 7.6 Ra), and highlighted the similarity of the mantle sources feeding the volcanic activity of Mt. Etna and the Hyblean Plateau (a region to the south of Mt. Etna and characterized by oldermagmatismthan Mt. Etna). The coupling of noble gases and trace elements suggests an origin for the investigated Etnean lavas from melting of a Hyblean-like mantle, consisting of a two-component source where a peridotitic matrix is veined by 10% pyroxenite. A variable degree of mantle contamination by crustal-like fluids, probably related to subduction, is proposed to explain the higher Sr-isotope and lowerNd-isotope values in some rocks (143Nd/144Nd up to 0.512865 and 87Sr/86Sr up to 0.703707). This process probably occurred in the source prior tomagma generation, refertilizing some portions of themantle. Accordingly, the estimated degree of melting responsible for each magma appears to be related to its 87Sr/86Sr enrichment. In contrast, the decoupling between 3He/4He and 87Sr/86Sr ratios requires the occurrence in the crustal reservoirs of further processes capable of shifting the He isotope ratio towards slightly more radiogenic values, such as magma aging or a contribution of shallow fluid. Therefore, different residence times in the Etnean reservoir and/or various rates of magma ascent could be key parameters for preserving the original He isotope marker of the Etnean mantle source. © 2013 Published by Elsevier
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