594 research outputs found

    Fabrication and characterization of Ag- and Ga-doped mesoporous glass-coated scaffolds based on natural marine sponges with improved mechanical properties

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    Natural marine sponges were used as sacrificial template for the fabrication of bioactive glassbased scaffolds. After sintering at 1050 ºC, the resulting samples were additionally coated with a sol silicate solution containing biologically active ions (Ag and Ga), well-known for their antibacterial properties in comparison with standard scaffolds made by PU foam templates. The produced scaffolds were characterized by superior mechanical properties (maximum compressive strength of 4 MPa) and total porosity of ~80%. Direct cell culture tests performed on the uncoated and coated samples showed positive results in terms of adhesion, proliferation, and differentiation of MC3T3-E1 cells. Moreover, vascular endothelial growth factor (VEGF) secretion from cells in contact with scaffold dissolution products was measured after 7 and 10 days of incubation, showing promising angiogenic results for bone tissue engineering applications. The antibacterial potential of the produced samples was assessed by performing agar diffusion tests against both Gram-positive and Gram-negative bacteria.EU Horizon 2020 project COACH 64255

    Exploring the bulk of the BL Lac object population:1. parsec-scale radio structures

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    Context. The advent of Fermi is changing our understanding on the radio and gamma-ray emission in Active Galactic Nuclei. Contrary to pre-Fermi ideas, BL Lac objects are found to be the most abundant emitters in the gamma-ray band. However, since they are relatively weak radio sources, most of their parsec-scale structure and their multi-frequency properties are poorly understood and/or have not been investigated in a systematically fashion. Aims. Our main goal is to analyze the radio and gamma-ray emission properties of a sample of 42 BL Lacs selected, for the first time in the literature, with no constraint on their radio and gamma-ray flux densities/emission. Methods. Thanks to new Very Long Baseline Array observations at 8 and 15 GHz for the whole sample, we present here fundamental parameters such as radio flux densities, spectral index information, and parsec-scale structure. Moreover, we search for gamma-ray counterparts using data reported in the Second Catalog of Fermi Gamma-ray sources. Results. Parsec-scale radio emission is observed in the majority of the sources at both frequencies. Gamma-ray counterparts are found for 14/42 sources. Conclusions. The comparison between our results in radio and gamma-ray bands points out the presence of a large number of faint BL Lacs showing "non classical" properties such as low source compactness, core dominance, no gamma-ray emission and steep radio spectral indexes. A deeper multiwavelength analysis will be needed.Comment: 19 pages, 6 figures, 6 tables, accepted for publication in A&

    Infrared Thermography to an Aluminium Foam Sandwich Structure Subjected to Low Velocity Impact Tests

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    Abstract This work is the straightforward continuation of previous ones in which vibro-acoustic characteristics of AFS panels were investigated both numerically and experimentally. Herein, the use of infrared thermography (IRT) is exploited to investigate impact damaging of an aluminium foam sandwich panel by monitoring its surface, opposite to the impact, during a low velocity impact test, which is performed with a modified Charpy pendulum. Thermal images, acquired in time sequence during the impact by the infrared camera, are post-processed to get information useful for understanding absorption capabilities and impact damaging mechanisms of this kind of structure

    Elevated blood pressure reduction after α-lipoic acid supplementation: a meta-analysis of randomized controlled trials

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    The aim of the comprehensive meta-analysis was to systematically explore the reductive effect of α-lipoic acid (ALA) supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP). The related records were selected from PubMed, Scopus, EMBASE, Cochrane library, and Persian databases including SID and Magiran from earliest date 1980 until August 2018. The heterogeneities were assessed by I 2 test (I 2 < 50) and � 2 test on Cochrane�s Q statistic. Standardized mean difference (SMD) and their 95 confidence intervals (CIs) were estimated for change in SBP and DBP. Subgroup analyses were also carried out by baseline BP, clinical condition, dosage of supplementation, and duration of study. As a result, a total of seven studies with 478 participants were included in the meta-analysis. Compared to the controls, ALA supplementation significantly reduced both SBP (SMD = �0.81, 95 CI: �1.20, �0.41) and DBP (SMD = �1.50, 95 CI: �2.86, �0.15) with a reduction of 8.1 and 6.7 mmHg of the mean SBP and DBP, respectively. Significant heterogeneity was detected in SBP and DBP; however, subgroup analysis of baseline BP showed significant reduction in both SBP and DBP heterogeneities. Indeed, a statistically significant reduction in BP was observed in subsets of elevated BP as compared with hypertensive patients. In conclusion, the current meta-analysis revealed that ALA supplementation lowers BP in subjects, especially those with elevated BP. © 2019, Springer Nature Limited

    Security challenges of small cell as a service in virtualized mobile edge computing environments

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    Research on next-generation 5G wireless networks is currently attracting a lot of attention in both academia and industry. While 5G development and standardization activities are still at their early stage, it is widely acknowledged that 5G systems are going to extensively rely on dense small cell deployments, which would exploit infrastructure and network functions virtualization (NFV), and push the network intelligence towards network edges by embracing the concept of mobile edge computing (MEC). As security will be a fundamental enabling factor of small cell as a service (SCaaS) in 5G networks, we present the most prominent threats and vulnerabilities against a broad range of targets. As far as the related work is concerned, to the best of our knowledge, this paper is the first to investigate security challenges at the intersection of SCaaS, NFV, and MEC. It is also the first paper that proposes a set of criteria to facilitate a clear and effective taxonomy of security challenges of main elements of 5G networks. Our analysis can serve as a staring point towards the development of appropriate 5G security solutions. These will have crucial effect on legal and regulatory frameworks as well as on decisions of businesses, governments, and end-users

    A meta-analysis of randomized control trials: The impact of vitamin c supplementation on serum crp and serum hs-crp concentrations

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    Objective: The present meta-analysis was designed to assess the effects of vitamin C supplementation on serum C-reactive Protein (CRP) levels. Methods: We conducted a comprehensive systematic search of the literature in Scopus, PubMed and Google Scholar until May 2018. The pooled Weighted Mean Difference (WMD) and its 95 Confidence Interval (CI) in baseline and at the end of the trial were calculated to assess the net change in serum CRP by using random-effects model. The heterogeneity was assessed by I2 test. Combined and stratified analyses were used in the meta-analysis. Results: From 306 articles found and screened in our initial search, 12 studies were included with 446 participants in supplementation groups and 447 in control groups. The pooled effect size analysis showed a significant reducing effect of vitamin C supplementation on circulating CRP level (�0.23 mg/L, 95 CI, �0.44,-0.03, p=0.02), with a significant heterogeneity effect across the studies involved. Subgroup analyses showed that vitamin C supplementation significantly lowered CRP among trials. The most significant effect was found 1) on hs-CRP as the representative inflammatory marker (-0.43 mg/L, 95 CI-0.76,-0.1) 2) in subjects with a baseline CRP�3 (-1.48 mg/L, 95 CI-2.84,-0.11) 3) in subjects under <60 years old of age (-0.23 mg/L, 95 CI-0.44,-0.01) 4) or using intravenous administration of vitamin C (-0.89 mg/L, 95 CI-1.49,-0.3). Conclusion: The present meta-analysis shows that vitamin C supplementation reduces serum CRP level, particularly in younger subjects, with higher CRP baseline level, at a lower dosage and intravenous administration. © 2018, Bentham Science Publishers B.V. All rights reserved

    Multiple RF classifier for the hippocampus segmentation: method and validation on EADC-ADNI harmonized hippocampal protocol

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    AbstractThe hippocampus has a key role in a number of neurodegenerative diseases, such as Alzheimer's Disease. Here we present a novel method for the automated segmentation of the hippocampus from structural magnetic resonance images (MRI), based on a combination of multiple classifiers. The method is validated on a cohort of 50 T1 MRI scans, comprehending healthy control, mild cognitive impairment, and Alzheimer's Disease subjects. The preliminary release of the EADC-ADNI Harmonized Protocol training labels is used as gold standard. The fully automated pipeline consists of a registration using an affine transformation, the extraction of a local bounding box, and the classification of each voxel in two classes (background and hippocampus). The classification is performed slice-by-slice along each of the three orthogonal directions of the 3D-MRI using a Random Forest (RF) classifier, followed by a fusion of the three full segmentations. Dice coefficients obtained by multiple RF (0.87 ± 0.03) are larger than those obtained by a single monolithic RF applied to the entire bounding box, and are comparable to state-of-the-art. A test on an external cohort of 50 T1 MRI scans shows that the presented method is robust and reliable. Additionally, a comparison of local changes in the morphology of the hippocampi between the three subject groups is performed. Our work showed that a multiple classification approach can be implemented for the segmentation for the measurement of volume and shape changes of the hippocampus with diagnostic purposes

    MRI analysis for Hippocampus segmentation on a distributed infrastructure

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    Medical image computing raises new challenges due to the scale and the complexity of the required analyses. Medical image databases are currently available to supply clinical diagnosis. For instance, it is possible to provide diagnostic information based on an imaging biomarker comparing a single case to the reference group (controls or patients with disease). At the same time many sophisticated and computationally intensive algorithms have been implemented to extract useful information from medical images. Many applications would take great advantage by using scientific workflow technology due to its design, rapid implementation and reuse. However this technology requires a distributed computing infrastructure (such as Grid or Cloud) to be executed efficiently. One of the most used workflow manager for medical image processing is the LONI pipeline (LP), a graphical workbench developed by the Laboratory of Neuro Imaging (http://pipeline.loni.usc.edu). In this article we present a general approach to submit and monitor workflows on distributed infrastructures using LONI Pipeline, including European Grid Infrastructure (EGI) and Torque-based batch farm. In this paper we implemented a complete segmentation pipeline in brain magnetic resonance imaging (MRI). It requires time-consuming and data-intensive processing and for which reducing the computing time is crucial to meet clinical practice constraints. The developed approach is based on web services and can be used for any medical imaging application
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