152 research outputs found

    The physics of spreading processes in multilayer networks

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    The study of networks plays a crucial role in investigating the structure, dynamics, and function of a wide variety of complex systems in myriad disciplines. Despite the success of traditional network analysis, standard networks provide a limited representation of complex systems, which often include different types of relationships (i.e., "multiplexity") among their constituent components and/or multiple interacting subsystems. Such structural complexity has a significant effect on both dynamics and function. Throwing away or aggregating available structural information can generate misleading results and be a major obstacle towards attempts to understand complex systems. The recent "multilayer" approach for modeling networked systems explicitly allows the incorporation of multiplexity and other features of realistic systems. On one hand, it allows one to couple different structural relationships by encoding them in a convenient mathematical object. On the other hand, it also allows one to couple different dynamical processes on top of such interconnected structures. The resulting framework plays a crucial role in helping achieve a thorough, accurate understanding of complex systems. The study of multilayer networks has also revealed new physical phenomena that remain hidden when using ordinary graphs, the traditional network representation. Here we survey progress towards attaining a deeper understanding of spreading processes on multilayer networks, and we highlight some of the physical phenomena related to spreading processes that emerge from multilayer structure.Comment: 25 pages, 4 figure

    Characterizing the Chemical Profile of Incidental Ultrafine Particles for Toxicity Assessment Using an Aerosol Concentrator

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    Incidental ultrafine particles (UFPs) constitute a key pollutant in industrial workplaces. However, characterizing their chemical properties for exposure and toxicity assessments still remains a challenge. In this work, the performance of an aerosol concentrator (Versatile Aerosol Concentration Enrichment System, VACES) was assessed to simultaneously sample UFPs on filter substrates (for chemical analysis) and as liquid suspensions (for toxicity assessment), in a high UFP concentration scenario. An industrial case study was selected where metal-containing UFPs were emitted during thermal spraying of ceramic coatings. Results evidenced the comparability of the VACES system with online monitors in terms of UFP particle mass (for concentrations up to 95 µg UFP/m3 ) and between filters and liquid suspensions, in terms of particle composition (for concentrations up to 1000 µg/ m3). This supports the applicability of this tool for UFP collection in view of chemical and toxicological characterization for incidental UFPs. In the industrial setting evaluated, results showed that the spraying temperature was a driver of fractionation of metals between UF (<0.2 µm) and fine (0.2– 2.5 µm) particles. Potentially health hazardous metals (Ni, Cr) were enriched in UFPs and depleted in the fine particle fraction. Metals vaporized at high temperatures and concentrated in the UF fraction through nucleation processes. Results evidenced the need to understand incidental particle formation mechanisms due to their direct implications on particle composition and, thus, exposure. It is advisable that personal exposure and subsequent risk assessments in occupational settings should include dedicated metrics to monitor UFPs (especially, incidental).What’s important about this paper: Our work addresses the challenge of characterizing the bulk chemical composition of ultrafine particles in occupational settings, for exposure and toxicity assessments. We tested the performance of an aerosol concentrator (VACES) to simultaneously sample ultrafine particles (UFPs) on filter substrates and as liquid suspensions, in a high UFP concentration scenario. An industrial case study was selected where metal-bearing UFPs were emitted. We report the chemical exposures characterized in the industrial facility, and evidence the comparability of the VACES system with online monitors for UFP particle mass (up to 95 µg UFP/m3) as well as between UFP chemical composition on filters and in suspension. This supports the applicability of this tool for UFP collection in view of chemical and toxicological characterization of exposures to incidental UFPs in workplace settings.Highlights: - The VACES system is a useful tool for UFP sampling in high-concentration settings; - UFP collected simultaneously on filters and in suspension showed good comparability; - UFP chemical profiles were characterized; - Health-hazardous metals Ni and Cr accumulated in UFPs; - Understanding emission mechanisms is key to identifying exposure sources.This work was funded by SIINN ERA-NET (project id: 16), the Spanish MINECO (PCIN-2015-173-C02-01) and the French agency (Region Hauts de France). The Spanish Ministry of Science and Innovation (Project CEX2018-000794-S; Severo Ochoa) and the Generalitat de Catalunya (project number: AGAUR 2017 SGR41) provided support for the indirect costs for the Institute of Environmental Assessment and Water Research (IDAEA-CSIC). We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).info:eu-repo/semantics/publishedVersio

    Textiloma: a case of foreign body mimicking a spinal mass

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    Items such as cotton or gauze pads can be mistakenly left behind during operations. Such foreign materials (called textilomas or gossypibomas) cause foreign body reaction in the surrounding tissue. The complications caused by these foreign bodies are well known, but cases are rarely published because of medico-legal implications. Some textilomas cause infection or abscess formation in the early stage, whereas others remain clinically silent for many years. Here, we describe a case of textiloma in which the patient presented with low-back pain 4 years after lumbar discectomy. Imaging revealed an abcess-like mass in the lumbar epidural space

    Evaluation of the proliferation markers Ki-67/MIB-1, mitosin, survivin, pHH3, and DNA topoisomerase IIα in human anaplastic astrocytomas - an immunohistochemical study

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    <p>Abstract</p> <p>Background</p> <p>Histological malignancy grading of astrocytomas can be challenging despite criteria given by the World Health Organisation (WHO). Grading is fundamental for optimal prognostication and treatment, and additional biomarkers are needed to support the histopathological diagnosis. Estimation of proliferative activity has gained much enthusiasm, and the present study was designed to evaluate and compare novel immunohistochemical proliferative markers in human anaplastic astrocytomas.</p> <p>Methods</p> <p>Proliferative activity was determined in twenty-seven cases with antibodies reactive against the Ki-67 antigen, mitosin, survivin, pHH3, and DNA topoisomerase IIα, and they were mutually compared as well as related to mitotic activity.</p> <p>Results</p> <p>The markers correlated well with each other, but poorly with mitoses, probably because of small and squeezed tumour samples, in which identification of mitoses can be difficult. Positive association to overall survival was observed as well.</p> <p>Conclusions</p> <p>Our data show that these markers may assist significantly in the evaluation of proliferative activity in anaplastic astrocytomas and even have prognostic value.</p

    Opinion formation in multiplex networks with general initial distributions

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    We study opinion dynamics over multiplex networks where agents interact with bounded confidence. Namely, two neighbouring individuals exchange opinions and compromise if their opinions do not differ by more than a given threshold. In literature, agents are generally assumed to have a homogeneous confidence bound. Here, we study analytically and numerically opinion evolution over structured networks characterised by multiple layers with respective confidence thresholds and general initial opinion distributions. Through rigorous probability analysis, we show analytically the critical thresholds at which a phase transition takes place in the long-term consensus behaviour, over multiplex networks with some regularity conditions. Our results reveal the quantitative relation between the critical threshold and initial distribution. Further, our numerical simulations illustrate the consensus behaviour of the agents in network topologies including lattices and, small-world and scale-free networks, as well as for structure-dependent convergence parameters accommodating node heterogeneity. We find that the critical thresholds for consensus tend to agree with the predicted upper bounds in Theorems 4 and 5 in this paper. Finally, our results indicate that multiplexity hinders consensus formation when the initial opinion configuration is within a bounded range and, provide insight into information diffusion and social dynamics in multiplex systems modeled by networks

    Effectiveness of the 13-valent pneumococcal conjugate vaccine in preventing invasive pneumococcal disease in children aged 7-59 months. A matched case-control study

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    Background The 13-valent pneumococcal conjugate vaccine (PCV13) was licensed based on the results of immunogenicity studies and correlates of protection derived from randomized clinical trials of the 7-valent conjugate pneumococcal vaccine. We assessed the vaccination effectiveness (VE) of the PCV13 in preventing invasive pneumococcal disease (IPD) in children aged 7-59 months in a population with suboptimal vaccination coverage of 55%. Methods The study was carried out in children with IPD admitted to three hospitals in Barcelona (Spain) and controls matched by hospital, age, sex, date of hospitalization and underlying disease. Information on the vaccination status was obtained from written medical records. Conditional logistic regression was made to estimate the adjusted VE and 95% confidence intervals (CI). Results 169 cases and 645 controls were included. The overall VE of ≥1 doses of PCV13 in preventing IPD due to vaccine serotypes was 75.8% (95% CI, 54.1-87.2) and 90% (95% CI, 63.9-97.2) when ≥2 doses before 12 months, two doses on or after 12 months or one dose on or after 24 months, were administered. The VE of ≥1 doses was 89% (95% CI, 42.7-97.9) against serotype 1 and 86.0% (95% CI, 51.2-99.7) against serotype 19A. Serotype 3 showed a non-statistically significant effectiveness (25.9%; 95% CI, -65.3 to 66.8). Conclusions The effectiveness of ≥1 doses of PCV13 in preventing IPD caused by all PCV13 serotypes in children aged 7-59 months was good and, except for serotype 3, the effectiveness of ≥1 doses against the most frequent PCV13 serotypes causing IPD was high when considered individually

    EEG for good outcome prediction after cardiac arrest: a multicentre cohort study.

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    AIM Assess the prognostic ability of a non-highly malignant and reactive EEG to predict good outcome after cardiac arrest (CA). METHODS Prospective observational multicentre substudy of the "Targeted Hypothermia versus Targeted Normothermia after Out-of-hospital Cardiac Arrest Trial", also known as the TTM2-trial. Presence or absence of highly malignant EEG patterns and EEG reactivity to external stimuli were prospectively assessed and reported by the trial sites. Highly malignant patterns were defined as burst-suppression or suppression with or without superimposed periodic discharges. Multimodal prognostication was performed 96 hours after CA. Good outcome at 6 months was defined as a modified Rankin Scale score of 0-3. RESULTS 873 comatose patients at 59 sites had an EEG assessment during the hospital stay. Of these, 283 (32%) had good outcome. EEG was recorded at a median of 69 hours (IQR 47-91) after CA. Absence of highly malignant EEG patterns was seen in 543 patients of whom 255 (29% of the cohort) had preserved EEG reactivity. A non-highly malignant and reactive EEG had 56% (CI 50-61) sensitivity and 83% (CI 80-86) specificity to predict good outcome. Presence of EEG reactivity contributed (p<0.001) to the specificity of EEG to predict good outcome compared to only assessing background pattern without taking reactivity into account. CONCLUSION Nearly one-third of comatose patients resuscitated after CA had a non-highly malignant and reactive EEG that was associated with a good long-term outcome. Reactivity testing should be routinely performed since preserved EEG reactivity contributed to prognostic performance

    Association between exposure to air pollution and blood lipids in the general population of Spain.

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    Background and Aims: We aimed to assess the associations of exposure to air pollutants and standard and advanced lipoprotein measures, in a nationwide sample representative of the adult population of Spain.Methods: We included 4647 adults (>18 years), participants in the national, cross- sectional, population- based [email protected] study, conducted in 2008– 2010. Standard lipid measurements were analysed on an Architect C8000 Analyzer (Abbott Laboratories SA). Lipoprotein analysis was made by an advanced 1H- NMR lipoprotein test (Liposcale®). Participants were assigned air pollution con-centrations for particulate matter <10 μm (PM10), <2.5 μm (PM2.5) and nitrogen dioxide (NO2), corresponding to the health examination year, obtained by mod-elling combined with measurements taken at air quality stations (CHIMERE chemistry- transport model).Results: In multivariate linear regression models, each IQR increase in PM10, PM2.5 and NO2 was associated with 3.3%, 3.3% and 3% lower levels of HDL- c and 1.3%, 1.4% and 1.1% lower HDL particle (HDL- p) concentrations (p< .001 for all associations). In multivariate logistic regression, there was a significant associa-tion between PM10, PM2.5 and NO2 concentrations and the odds of presenting low HDL- c (<40 mg/dL), low HDL- p (<p25) and higher LDL particle (LDL- p) concentrations (≥p75). In subgroup analyses there were stronger associations be-tween PM10 and NO2 and low HDL- p in men (p for interaction .008 and .034), and between NO2 and low HDL- p in individuals with obesity (p for interaction .015).Conclusions: Our study shows an association between the exposure to air pol-lutants and blood lipids in the general population of Spain, suggesting a link to atherosclerosisFunding for open access charge: Universidad de Málaga / CBU

    Intrahepatic cholestasis of pregnancy

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    Intrahepatic cholestasis of pregnancy (ICP) is a cholestatic disorder characterized by (i) pruritus with onset in the second or third trimester of pregnancy, (ii) elevated serum aminotransferases and bile acid levels, and (iii) spontaneous relief of signs and symptoms within two to three weeks after delivery. ICP is observed in 0.4–1% of pregnancies in most areas of Central and Western Europe and North America, while in Chile and Bolivia as well as Scandinavia and the Baltic states roughly 5–15% and 1–2%, respectively, of pregnancies are associated with ICP. Genetic and hormonal factors, but also environmental factors may contribute to the pathogenesis of ICP. Intrahepatic cholestasis of pregnancy increases the risk of preterm delivery (19–60%), meconium staining of amniotic fluid (27%), fetal bradycardia (14%), fetal distress (22–41%), and fetal loss (0.4–4.1%), particularly when associated with fasting serum bile acid levels > 40 μmol/L. The hydrophilic bile acid ursodeoxycholic acid (10–20 mg/kg/d) is today regarded as the first line treatment for intrahepatic cholestasis of pregnancy. Delivery has been recommended in the 38th week when lung maturity has been established
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