1,454 research outputs found

    Interactive effects between carbon allotrope fillers on the mechanical reinforcement of polyisoprene based nanocomposites

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    Interactive effects of carbon allotropes on the mechanical reinforcement of polymer nanocomposites were investigated. Carbon nanotubes (CNT) and nano-graphite with high shape anisotropy (nanoG) were melt blended with poly(1,4- cis-isoprene), as the only fillers or in combination with carbon black (CB), measuring the shear modulus at low strain amplitudes for peroxide crosslinked composites. The nanofiller was found to increase the low amplitude storage modulus of the matrix, with or without CB, by a factor depending on nanofiller type and content. This factor, fingerprint of the nanofiller, was higher for CNT than for nanoG. The filler-polymer interfacial area was able to correlate modulus data of composites with CNT, CB and with the hybrid filler system, leading to the construction of a common master curve. © BME-PT

    Master curves for the mechanical reinforcement of diene elastomers with sp2 carbon allotropes

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    sp2 carbon allotropes are efficient reinforcing fillers for polymer melt and elastomers: carbon black (CB) has been used since early 1900’s and nanofillers such as carbon nanotubes (CNT), graphene and graphene related materials (GRM) have increased their importance over the last decades. Nanofillers can definitely establish larger interfacial area with the polymer matrix than CB and great impact on material properties is thus expected. However, it is widely acknowledged that they will not be able to completely replace CB. Hence, increasing research efforts are on hybrid systems based on CB-CNT and CB-GRM [1]. Research objective is to identify common features and behaviour of nano (CNT, GRM) and nanostructured (CB) sp2 carbon allotropes. In this work, initial modulus was determined by means of dynamic-mechanical shear measurements of composites based on either poly(1,4-cis-isoprene) or poly(styrene-co-butadiene) as the rubber and either CB or CNT or GRM or hybrid systems as the reinforcing fillers. Filler-polymer interfacial area (i.a.), calculated as the product of filler surface area, density and volume fraction, was used to establish a common correlation with the composite initial modulus. A sort of master curve was derived, able to fit all the points up to interfacial area of about 27 μm-1, corresponding to remarkable filler content. Much better efficiency was shown by carbon fillers, when composites were prepared through latex blending. To allow easy dispersion in rubber latex, sp2 carbon allotropes were functionalized with a serinol derivative: 2-(2,5-dimethyl- 1H-pyrrol-1-yl)-1,3-propanediol (serinol pyrrole, SP) [2, 3], shown in Figure 1

    Effect of organic treatments on soil carbon and nitrogen dynamics in vineyard

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    The work aims to investigate the effects of different soil management strategies on carbon sequestration and total nitrogen in areas of vineyards suffering from loss of soil functionality. Treatments, selected for inter-row management, to re-install soil functionality were based on compost or other organic amendments (COMP), green manure (GM), and dry mulching (DM) strategies using winter legumes and cereals. Cover crops were seeded in fall and mown in late spring, leaved in the ground for mulching in DM or incorporated into the uppermost soil layers in GM. Such approaches were investigated in six vineyards in Italy, six in France, and two vineyards in Slovenia and Turkey. The results showed that COMP significantly increased total organic carbon (TOC) and total nitrogen (Ntot) in the topsoil after one year of application. Also DM tends to increase significantly TOC in the topsoil, but only after two years. Modelling 20-year carbon stock dynamics in Italy vineyards, the average increase resulted 0.49, 0.34, 0.21 and 0.03 Mg C ha-1 yr-1 for COMP, DM, GM and control, respectively

    Edoxaban: an update on the new oral direct factor Xa inhibitor.

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    Edoxaban is a once-daily oral anticoagulant that rapidly and selectively inhibits factor Xa in a concentration-dependent manner. This review describes the extensive clinical development program of edoxaban, including phase III studies in patients with non-valvular atrial fibrillation (NVAF) and symptomatic venous thromboembolism (VTE). The ENGAGE AF-TIMI 48 study (N = 21,105; mean CHADS2 score 2.8) compared edoxaban 60 mg once daily (high-dose regimen) and edoxaban 30 mg once daily (low-dose regimen) with dose-adjusted warfarin [international normalized ratio (INR) 2.0-3.0] and found that both regimens were non-inferior to warfarin in the prevention of stroke and systemic embolism in patients with NVAF. Both edoxaban regimens also provided significant reductions in the risk of hemorrhagic stroke, cardiovascular mortality, major bleeding and intracranial bleeding. The Hokusai-VTE study (N = 8,292) in patients with symptomatic VTE had a flexible treatment duration of 3-12 months and found that following initial heparin, edoxaban 60 mg once daily was non-inferior to dose-adjusted warfarin (INR 2.0-3.0) for the prevention of recurrent VTE, and also had a significantly lower risk of bleeding events. Both studies randomized patients at moderate-to-high risk of thromboembolic events and were further designed to simulate routine clinical practice as much as possible, with edoxaban dose reduction (halving dose) at randomisation or during the study if required, a frequently monitored and well-controlled warfarin group, a well-monitored transition period at study end and a flexible treatment duration in Hokusai-VTE. Given the phase III results obtained, once-daily edoxaban may soon be a key addition to the range of antithrombotic treatment options

    Soil functionality assessment in degraded plots of vineyards

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    Land transformation to adapt fields to mechanization in perennial crop farming is a common practice which includes land levelling, deep ploughing, stone-breakage and clearing, application of fertilizers and amendments. Manipulation of the natural soil profile along its entire depth can severely disturb the naturally existing chemical physical,biological and hydrological equilibrium (Costantini and Barbetti, 2008; Costantini et al., 2013). The most common effects of the land transformation are mixing of soil horizons and soil truncation, which result in reduction of soil depth and available water, organic matter depletion, enrichment of calcium carbonate content in the topsoil,imbalance of some element ratio, and decline in the activity and diversity of soil biological communities involved in nutrient cycles. A decline in the capacity of soil to accommodate the soil-dwelling organisms causes a strong impact on several ecosystem services, in particular, the growth of the vine, the quality and quantity of the grapes,the production costs and the risk of erosion. These negative effects of a pre-planting mismanagement can occur simultaneously and interact to decrease soil fertility and grapevine performance (Lanyon et al., 2004; Tagliavini and Rombolà, 2001; Martínez-Casasnovas and Ramos, 2009).Since soil spatial variability is usually high, soil manipulations frequently result into reduced soil functionality and decline of soil ecosystem services in defined plots of the vineyards. Sometimes soil degradation in these areas is very high and compromises not only vine performance and crop yield, but also disease resistance of plants to diseases and their survival. The impact of improper soil manipulations in vineyards may be of particular concern, because vineyards are frequently located on marginal hillsides, which are sensitive to soil erosion and characterized by shallow soil depth (Ramos, 2006). This paper wants to show the assessment of soil functionality in degraded areas within two farms in Tuscany. This work reports the results of the first activities in Italian sites of the ReSolVe Core-organic+ project, aimed at restoring optimal Soil functionality in degraded areas within organic European vineyards

    Resolution of the type material of the Asian elephant, Elephas maximus Linnaeus, 1758 (Proboscidea, Elephantidae)

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    The understanding of Earth’s biodiversity depends critically on the accurate identification and nomenclature of species. Many species were described centuries ago, and in a surprising number of cases their nomenclature or type material remain unclear or inconsistent. A prime example is provided by Elephas maximus, one of the most iconic and well-known mammalian species, described and named by Linnaeus (1758) and today designating the Asian elephant. We used morphological, ancient DNA (aDNA), and high-throughput ancient proteomic analyses to demonstrate that a widely discussed syntype specimen of E. maximus, a complete foetus preserved in ethanol, is actually an African elephant, genus Loxodonta. We further discovered that an additional E. maximus syntype, mentioned in a description by John Ray (1693) cited by Linnaeus, has been preserved as an almost complete skeleton at the Natural History Museum of the University of Florence. Having confirmed its identity as an Asian elephant through both morphological and ancient DNA analyses, we designate this specimen as the lectotype of E. maximus

    Pathways for outpatient management of venous thromboembolism in a UK centre.

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    It has become widely recognised that outpatient treatment may be suitable for many patients with venous thromboembolism. In addition, non-vitamin K antagonist oral anticoagulants that have been approved over the last few years have the potential to be an integral component of the outpatient care pathway, owing to their oral route of administration, lack of requirement for routine anticoagulation monitoring and simple dosing regimens. A robust pathway for outpatient care is also vital; one such pathway has been developed at Sheffield Teaching Hospitals in the UK. This paper describes the pathway and the arguments in its favour as an example of best practice and value offered to patients with venous thromboembolism. The pathway has two branches (one for deep vein thrombosis and one for pulmonary embolism), each with the same five-step process for outpatient treatment. Both begin from the point that the patient presents (in the Emergency Department, Thrombosis Clinic or general practitioner's office), followed by diagnosis, risk stratification, treatment choice and, finally, follow-up. The advantages of these pathways are that they offer clear, evidence-based guidance for the identification, diagnosis and treatment of patients who can safely be treated in the outpatient setting, and provide a detailed, stepwise process that can be easily adapted to suit the needs of other institutions. The approach is likely to result in both healthcare and economic benefits, including increased patient satisfaction and shorter hospital stays
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