Thermal conductivity of amorphous polymers and its dependence on molecular weight

Thermal conductivity is an important transport property governing the performance of polymers in non-isothermal conditions. Nevertheless, its dependence on molecular weight M has not been the subject of as much attention as other properties of polymeric materials. We determine the thermal conductivity of polystyrene and polyisobutylene for a wide range of molecular weight by measuring the density, heat capacity and thermal diffusivity. Using coarse-graining and reverse mapping methods, we were able to produce molecular melts to study the thermal conductivity of polystyrene using molecular dynamics simulations over a similar range of molecular weight. We find satisfactory agreement between the experimental and simulation results. However, all of our results show that thermal conductivity depends only slightly on molecular weight up the entanglement limit and it is independent thereafter. Our results put into question the few previous experimental studies on this topic by showing that the previously accepted proportionality to $\sqrt{M}$ does not hold. Our findings could have significant implications for the understanding of complex phenomena such as anisotropic thermal conductivity in polymers subjected to flow.Marie Skłodowska-Curie IF MTCIATTP 750985

Development and validation of a method to estimate COPD severity in multiple datasets: a retrospective study

Introduction Outcomes in chronic obstructive pulmonary disease (COPD) such as symptoms, hospitalisations and mortality rise with increasing disease severity. However, the heterogeneity of electronic medical records presents a significant challenge in measuring severity across geographies. We aimed to develop and validate a method to approximate COPD severity using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2011 classification scheme, which categorises patients based on forced expiratory volume in 1 s, hospitalisations and the modified Medical Research Council dyspnoea scale or COPD Assessment Test. Methods This analysis was part of a comprehensive retrospective study, including patients sourced from the IQVIA Medical Research Data [IMRD; incorporating data from The Health Improvement Network (THIN), a Cegedim database] and the Clinical Practice Research Datalink (CPRD) in the UK, the Disease Analyzer in Germany and the Longitudinal Patient Data in Italy, France and Australia. Patients in the CPRD with the complete set of information required to calculate GOLD 2011 groups were used to develop the method. Ordinal logistic models at COPD diagnosis and at index (first episode of triple therapy) were then used to validate the method to estimate COPD severity, and this was applied to the full study population to estimate GOLD 2011 categories. Results Overall, 4579 and 12,539 patients were included in the model at COPD diagnosis and at index, respectively. Models correctly classified 74.4% and 75.9% of patients into severe and non-severe categories at COPD diagnosis and at index, respectively. Age, gender, time between diagnosis and start of triple therapy, healthcare resource use, comorbid conditions and prescriptions were included as covariates. Conclusion This study developed and validated a method to approximate disease severity based on GOLD 2011 categories that can potentially be used in patients without all the key parameters needed for this calculation

Prescribing pathways to triple therapy: a multi-country, retrospective observational study of adult patients with chronic obstructive pulmonary disease

Introduction Maintenance treatment strategies in COPD recommend inhaled corticosteroid (ICS) + long-acting muscarinic antagonist (LAMA) + long-acting β2-agonist (LABA) triple therapy after initial dual therapy. Little is known about how treatment pathways to triple therapy vary across countries in clinical practice. Methods This multi-country, retrospective cohort study (conducted 1 January 2005–1 May 2016) included patients with a COPD diagnosis, and (UK only) evidence of smoking history, or (France, Italy, Germany, and Australia) an indicator confirming COPD diagnosis, a first instance of triple therapy recorded during the study period and ≥ 12 months of data prior to this date. Treatment pathways to triple therapy were analyzed in patients whose first instance of triple therapy was on or after the initial COPD diagnosis. The proportion of patients who initiated triple therapy prior to initial COPD diagnosis was also estimated. Meta-analyses of the main results were performed. Results In 130,729 patients across all countries, mean age (standard deviation) ranged from 63.4 (10.4) years (Germany) to 69.8 (9.9) years (Italy), and median time (interquartile range) from initial COPD diagnosis to first prescription of triple therapy ranged from 16.9 (5.7–36.2) months (Australia) to 42.5 (13.9–87.4) months (UK). ICS + LABA was the most common treatment pathway prior to triple therapy in the UK, Germany, and Italy (27.3%–31.6%); no previous maintenance therapy prior to triple therapy was the most common pathway in France and Australia (32.5% and 37.9%, respectively). Meta-analyses provided a pooled estimate of 20.4% (95% confidence interval: 13.8%–29.1%) for the proportion of patients initiating triple therapy at or before initial COPD diagnosis. Conclusions In this retrospective cohort study, treatment pathways to triple therapy were diverse within and between countries. The differing impact of treatments may affect quality of life and disease control in patients with COPD. Further analyses should investigate factors influencing pathways to triple therapy

Acoustic telemetry and accelerometers: a field comparison of different proxies for activity in the marine environment

Different proxies for activity are used in the field of acoustic telemetry, a leading technology for the study of behaviour in the aquatic environment. Acoustic telemetry poses some shortcomings that may condition data interpretation. Here, we assessed some approaches commonly used to infer activity from acoustic telemetry data using acceleration biologgers as a benchmark. Specifically, we assessed (1) the performance of internal acceleration transmitters, (2) the consequences of averaging acceleration data into increasing time bins, (3) the occurrence of sampling bias in telemetry data acquisition, and (4) the performance of the number of detections and the depth range as proxies for activity. Despite some constraints of acoustic telemetry, acceleration transmitters had a good performance. Conversely, the number of detections and the depth range did not match well the activity estimates provided by acceleration biologgers. Besides, our results pointed to some issues in models concerning the predictive power of acceleration transmitters (linear predictor) over acceleration biologgers, warned about potential sampling bias associated with data acquisition with acoustic telemetry, and highlighted the relevance of considering inter-individual differences in behavioural studies. Finally, we provided some methodological perspectives that should be considered to plan fieldwork, analyse data, and interpret results on animal activity obtained with acoustic telemetry.info:eu-repo/semantics/publishedVersio

Flow field visualization of entangled polybutadiene solutions under nonlinear viscoelastic flow conditions

Using self-designed particle visualization instrumentation, startup shear and step-strain tests were conducted under a series of systematically varied rheological and geometrical conditions, and the velocity profiles in three different well-entangled polybutadiene/oligomer solutions were obtained. For startup shear tests, in the regime of entanglement densities up to 89 and nominal reptation Weissenberg numbers up to 18.6, we generally observe either wall slip and a linear velocity/strain profile or simply the linear profile with no wall slip unless a massive edge fracture or instability has occurred in the sample. Meanwhile, step-strain tests conducted at similar and higher step Weissenberg numbers revealed little particle motion upon cessation. These results lead us to a conclusion that there is no compelling evidence of shear banding or nonquiescent relaxation in the range of entanglement density and Wi investigated; we interpret the results to imply that any observed banding probably correlates with edge effects.National Science Foundation (U.S.) (Grant DMR-0934305

A global review of marine recreational spearfishing

24 pages, 5 figures, 2 tables, supplementary information https://doi.org/10.1007/s11160-023-09790-7.-- Data availability: The full list of papers used for the systematic review is available as a supplementary tableRecreational spearfishing is a fishing method that occurs globally, yet receives considerably less attention in the scientific literature relative to other recreational fishing methods, such as angling. Lack of scientific information on spearfishing may negatively affect the development and management of marine recreational fisheries. We conducted a systematic review of 102 peer-reviewed papers published between 1967 and 2022 pertaining to marine recreational spearfishing. Based on this literature review, we provide an overview of key insights across social, economic, and ecological dimensions of marine recreational spearfishing. While spearfishers represent less than 5% of marine recreational fishers, the participants are younger and may differ from recreational anglers in their motivations, with suggestions of increased well-being generated from a close connection with the sea during underwater fishing. Recreational spearfishers mostly target species of moderate to high levels of vulnerability that are mid to high trophic level carnivores. Though spearfishers can deliberately target larger individuals of exploited populations, this is not a generalizable pattern. Despite a growing body of research on the ecological impacts of marine recreational spearfishing, there is limited knowledge of these effects and their mechanisms across biological levels of organization (e.g., individual, population, community and ecosystem) compared with those of other fishing methods. Recreational spearfishers can contribute to advances in marine ecological knowledge, and inclusive participatory management could represent a key step towards transformative sustainable development of marine recreational spearfishing. Throughout the review, we identify gaps in the research and areas where future research is needed to better inform the socio-economic importance, ecosystem impacts and future management of marine recreational spearfishingVS was supported by a “Juan de la Cierva Incorporación” (IJC2018-035389-I), and he is now supported by a “Ramón y Cajal” research fellowships (RYC2021-033065-I) granted by the Spanish Ministry of Science and Innovation. SV and PP are supported by the Xunta de Galicia (RECREGES I and II projects under Grants ED481B2014/034-0 and ED481B2018/017), Grupo de Referencia Competitiva GI-2060 AEMI, under Grant ED431C2019/11), and Fundación Biodiversidad, Ministerio para la Transición Ecológica y el Reto Demográfico, Gobierno de España (SICORE and GT PMR projects). VJG received a postdoctoral grant (#2017/22273-0) from São Paulo Research Foundation (FAPESP). MR would like to acknowledge Portuguese national funds from FCT—Foundation for Science and Technology through projects UIDB/04326/2020, UIDP/04326/2020 and LA/P/0101/2020. MR would also like to acknowledge FCT funding through a postdoctoral grant (SFRH/BPD/116307/2016). JACCN thanks to Meros do Brasil Project sponsored by Petrobras. FJH is supported by a Sȇr Cymru European Regional Development Fund Fellowship (80761-SU-135). RA was supported by the German Federal Ministry of Education and Research (Grants 01LC1826E and 033W046A). ML is supported by the Agencia Nacional de Investigación e Innovación (ANII, POS_EXT_2020_1_165362). This work acknowledges the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S). [...] Open Access funding provided thanks to the CRUE-CSIC agreement with Springer NaturePeer reviewe

Direct Ophthalmic Healthcare Resource Use among Geographic Atrophy Patients in a Large Cohort from the United Kingdom

Objective To estimate the direct ophthalmic health care resource use in patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD). Design Retrospective analysis of anonymized data derived from electronic medical records acquired at 10 clinical sites in the United Kingdom. Participants Patients aged ≥50 years with ≥1 eye with a clinical record of GA or, for comparison, bilateral early/intermediate AMD. Four subgroups were identified: GA in both eyes (GA : GA); GA in 1 eye, choroidal neovascularization (CNV) in the fellow eye (GA : CNV); GA in 1 eye with early or intermediate AMD in the fellow eye (GA : E); and early/intermediate AMD in both eyes (E : E). Methods Electronic medical records were analyzed to derive the median number of visits over the first 2 years following diagnosis of GA or early/intermediate AMD. Clinical tests recorded at visits were used to calculate estimated costs (payer perspective) of monitoring. Analyses were restricted to patients with an initial diagnosis on or after January 1, 2011 to represent present day monitoring and costs associated with AMD. Main Outcome Measures Median number of visits and estimated monitoring costs per patient (in £) over the first 2 years among patients with ≥2 years of follow-up and in the individual subgroups. Intravitreal treatment costs in the GA : CNV group were excluded. Results For all 3 GA subgroups (n = 1080), the median number of visits over the first 2 years was 5 and monitoring costs were £460.80 per patient. The GA : CNV subgroup (n = 355) had the highest number of visits (median, 15), with a cost of £1581, compared with the GA : E subgroup (n = 283; median 4 visits; cost ∼£369) and the GA : GA subgroup (n = 442; median 3 visits; cost ∼£277). Ophthalmic tests were conducted most frequently in the GA : CNV subgroup. Visits and costs in the E : E subgroup (n = 6079) were lower. Conclusions Resource use in patients with GA varies considerably and is strongly influenced by the concomitant presence of CNV and lack of monitoring strategies for GA

Experimental and theoretical studies of nanofluid thermal conductivity enhancement: a review

Nanofluids, i.e., well-dispersed (metallic) nanoparticles at low- volume fractions in liquids, may enhance the mixture's thermal conductivity, knf, over the base-fluid values. Thus, they are potentially useful for advanced cooling of micro-systems. Focusing mainly on dilute suspensions of well-dispersed spherical nanoparticles in water or ethylene glycol, recent experimental observations, associated measurement techniques, and new theories as well as useful correlations have been reviewed