92 research outputs found

    A CFD‐based analysis of dynamic induction techniques for wind farm control applications

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    Summary Recently, dynamic induction control is gaining the interest of the wind energy community as a promising strategy to increase the overall wind farm power production. Such a technique is based on a dynamic variation of the upstream rotor thrust, generated through a suitable blade pitch motion, to promote a faster wake recovery. Notwithstanding some promising results already published, the knowledge of the physical mechanism, connecting dynamic induction to the increased in‐wake velocity, was not yet exploited to enhance control effectiveness. This paper, through a computational fluid dynamics procedure based on large eddy simulations coupled with actuator line models, provides a description of the working principles of this control from a fluid dynamics standpoint. The analyses show that the faster recovery is strictly connected to the ability of the blade tip vortices to roll up and sucking energy from the outer flow. Exploiting such knowledge, a novel control strategy, which improves the vortex roll up mechanism, is proposed and analyzed. The new control proved more effective than standard techniques especially for very low turbine spacing

    A Keynesian perspective on the health economics of kidney transplantation would strengthen the value of the whole organ donation and transplantation service

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    BackgroundIn this study, the Keynesian principle “savings may be used as investments in resources” is applied to Kidney Transplantation (KT), contextualizing the whole Organs Donation and Transplantation (ODT) service as a unique healthcare entity. Our aim was to define the financial resources that may be acquired in the form of savings from the KT activity.MethodsWe analyzed registry and funding data for ODT in our region, between 2015 and 2019. Our hypotheses aimed to evaluate whether the savings would offset the Organ Donation (OD) costs, define the scope for growth, and estimate what savings could be generated by higher KT activity. To facilitate the evaluation of the resources produced by KT, we defined a coefficient generated from the combination of clinical outcomes, activity, and costs.ResultsThe ODT activity reached a peak in 2017, declining through 2018–2019. The savings matured in 2019 from the KT activity exceeded €15 million while the OD costs were less than €9 million. The regional KT activity was superior to the national average but inferior to international benchmarks. The estimated higher KT activity would produce savings between €16 and 20 million.ConclusionThe financial resources produced by KT contribute to defining a comprehensive perspective of ODT finance. The optimization of the funding process may lead to the financial self-sufficiency of the ODT service. The reproducible coefficient allows a reliable estimate of savings, subsequently enabling adequate investments and budgeting. Applying such a perspective jointly with reliable estimates would establish the basis for an in-hospital fee-for-value funding methodology for ODT

    NS3 Variability in Hepatitis C Virus Genotype 1A Isolates from Liver Tissue and Serum Samples of Treatment-Naïve Patients with Chronic Hepatitis C.

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    Background: Hepatitis C virus (HCV) NS3 resistance-associated substitutions (RASs) reduce HCV susceptibility to protease inhibitors. Little is known about NS3 RASs in viral isolates from the liver of chronic hepatitis C (CHC) patients infected with HCV genotype-1a (G1a). Aim: The objective of this work was to study NS3 variability in isolates from the serum and liver of HCV-G1a-infected patients naïve to direct-acting antivirals (DAAs). Methods: NS3 variability of HCV-G1a isolates from the serum and liver of 11 naïve CHC patients, and from sera of an additional 20 naïve CHC patients, was investigated by next-generation sequencing. Results: At a cutoff of 1%, NS3 RASs were detected in all the samples examined. At a cutoff of 15%, they were found in 54.5% (6/11) and 27.3% (3/11) of the paired liver and serum samples, respectively, and in 22.5% (7/31) of the overall serum samples examined. Twenty-six out of thirty-one (84%) patients showed NS3 variants with multiple RASs. Phylogenetic analysis showed that NS3 sequences clustered within 2 clades, with 10/31 (32.2%) patients infected by clade I, 15/31 (48.8%) by clade II, and 6/31 (19.3%) by both clades. Conclusions: Though the number of patients examined was limited, NS3 variants with RASs appear to be major components of both intrahepatic and circulating viral quasispecies populations in DAA-naïve patients

    In vivo probabilistic atlas of white matter tracts of the human subthalamic area combining track density imaging and optimized diffusion tractography

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    The human subthalamic area is a region of high anatomical complexity, tightly packed with tiny fiber bundles. Some of them, including the pallidothalamic, cerebello-thalamic, and mammillothalamic tracts, are relevant targets in functional neurosurgery for various brain diseases. Diffusion-weighted imaging-based tractography has been suggested as a useful tool to map white matter pathways in the human brain in vivo and non-invasively, though the reconstruction of these specific fiber bundles is challenging due to their small dimensions and complex anatomy. To the best of our knowledge, a population-based, in vivo probabilistic atlas of subthalamic white matter tracts is still missing. In the present work, we devised an optimized tractography protocol for reproducible reconstruction of the tracts of subthalamic area in a large data sample from the Human Connectome Project repository. First, we leveraged the super-resolution properties and high anatomical detail provided by short tracks track-density imaging (stTDI) to identify the white matter bundles of the subthalamic area on a group-level template. Tracts identification on the stTDI template was also aided by visualization of histological sections of human specimens. Then, we employed this anatomical information to drive tractography at the subject-level, optimizing tracking parameters to maximize between-subject and within-subject similarities as well as anatomical accuracy. Finally, we gathered subject level tracts reconstructed with optimized tractography into a large-scale, normative population atlas. We suggest that this atlas could be useful in both clinical anatomy and functional neurosurgery settings, to improve our understanding of the complex morphology of this important brain region

    Colletotrichum clavatum sp. nov. identified as the causal agent of olive anthracnose in Italy

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    Molecular analyses of a large population of isolates, previously identified as group B or genetic group A4 of the Colletotrichum acutatum species complex, mainly of Italian origin from olive, but also from other hosts collected since 1992, confirmed a well-resolved phylogenetic lineage with distinctive phenotypic characters which can be recognized as a separate species. Based on RAPD genomic fingerprinting, ITS and β-tubulin DNA sequences, this species was clearly distinct from C. acutatum sensu stricto, C. fioriniae and C. simmondsii as well as from the genetic groups A1, A6, A7 and A8, all previously referred to as C. acutatum sensu lato. Group A4 is widespread in Europe, being responsible for olive anthracnose epidemics in some Mediterranean countries, including Greece, Italy, Montenegro, Portugal and Spain; moreover, it causes anthracnose diseases on a wide range of other hosts including about 20 different genera of woody and herbaceous plants, ornamentals and fruit trees. This new anamorphic taxon is described as Colletotrichum clavatum sp. nov

    Modelling of implantable sensor packaging based on biocompatible polymers

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    Implantable devices are being used for long term healthcare and human body physiological monitoring of specific parameters. PDMS (poly-dimethyl-siloxane) can be used either for sensor or for packaging of the same sensor in many applications, notably in laparoscopy and laparotomy as feeler pin in order to help surgeons to touch specific tissues and to get a response based on the nature of the touched tissue (softness). The need of calibrated pressure on a tissue arises when we are in presence particular pathologies or impairments as: cancer issues, high risk of aneurism for aorta and brain, probable haemorrhage in touching capillaries, and so forth. This paper presents a packaging modelling of a build nanosensor to be used in a human body for surgery exploration as laparoscopy and laparotomy. A nanosensor is first build for common application and adapted for implantable applications, and a packaging is studied. The designed sensor is implemented by considering PDMS as polymeric material

    Decline of jackfruit (Artocarpus heterophyllus) incited by Phytophthora palmivora in Vietnam

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    A new disease of jackfruit (Artocarpus heterophyllus Lam.) was observed in the south- eastern region of South Vietnam. Symptoms included root rot, cankers and gummosis of trunks, chlorosis, wilt, blight of leaves, defoliation, fruit brown rot, and tree death. The disease was found in 10% of surveyed farms with an incidence varying from 2% to nearly 60% of the trees. A Phytophthora species, identified as P. palmivora (Butler) Butler, using the ITS1-5.8S-ITS2 region of the rDNA as a barcode gene and morphological and cultural features, was consistently isolated from symptomatic roots, fruits, trunk cankers and leaves. Koch’s postulates were fulfilled using pathogenicity tests on seedlings, leaves and detached fruits of jackfruit. To our knowledge, this is the first report of P. palmivora on jackfruit in Vietnam

    The UK needs a sustainable strategy for COVID-19

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    The UK is well into the second wave of COVID-19, with 60 051 lives lost to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection to date, according to provisional data from the&nbsp;Office for National Statistics. Official UK Government&nbsp;data&nbsp;show that cases have been rising exponentially since late August, 2020, with increases across all regions in England in recent weeks. &nbsp;As of Nov 4, 2020, the UK had 25 177 confirmed daily cases. These are almost certainly underestimates as between Oct 17 and Oct 23, 2020, England alone had 52 000 estimated daily cases. &nbsp;Estimates of the effective reproduction number in England vary between 1·1 and 1·6.</p

    Serum Albumin Is Inversely Associated With Portal Vein Thrombosis in Cirrhosis

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    We analyzed whether serum albumin is independently associated with portal vein thrombosis (PVT) in liver cirrhosis (LC) and if a biologic plausibility exists. This study was divided into three parts. In part 1 (retrospective analysis), 753 consecutive patients with LC with ultrasound-detected PVT were retrospectively analyzed. In part 2, 112 patients with LC and 56 matched controls were entered in the cross-sectional study. In part 3, 5 patients with cirrhosis were entered in the in vivo study and 4 healthy subjects (HSs) were entered in the in vitro study to explore if albumin may affect platelet activation by modulating oxidative stress. In the 753 patients with LC, the prevalence of PVT was 16.7%; logistic analysis showed that only age (odds ratio [OR], 1.024; P = 0.012) and serum albumin (OR, -0.422; P = 0.0001) significantly predicted patients with PVT. Analyzing the 112 patients with LC and controls, soluble clusters of differentiation (CD)40-ligand (P = 0.0238), soluble Nox2-derived peptide (sNox2-dp; P &lt; 0.0001), and urinary excretion of isoprostanes (P = 0.0078) were higher in patients with LC. In LC, albumin was correlated with sCD4OL (Spearman's rank correlation coefficient [r(s)], -0.33; P &lt; 0.001), sNox2-dp (r(s), -0.57; P &lt; 0.0001), and urinary excretion of isoprostanes (r(s), -0.48; P &lt; 0.0001) levels. The in vivo study showed a progressive decrease in platelet aggregation, sNox2-dp, and urinary 8-iso prostaglandin F2 alpha-III formation 2 hours and 3 days after albumin infusion. Finally, platelet aggregation, sNox2-dp, and isoprostane formation significantly decreased in platelets from HSs incubated with scalar concentrations of albumin. Conclusion: Low serum albumin in LC is associated with PVT, suggesting that albumin could be a modulator of the hemostatic system through interference with mechanisms regulating platelet activation
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