6,105 research outputs found

    Phase diagrams of Janus fluids with up-down constrained orientations

    Full text link
    A class of binary mixtures of Janus fluids formed by colloidal spheres with the hydrophobic hemispheres constrained to point either up or down are studied by means of Gibbs ensemble Monte Carlo simulations and simple analytical approximations. These fluids can be experimentally realized by the application of an external static electrical field. The gas-liquid and demixing phase transitions in five specific models with different patch-patch affinities are analyzed. It is found that a gas-liquid transition is present in all the models, even if only one of the four possible patch-patch interactions is attractive. Moreover, provided the attraction between like particles is stronger than between unlike particles, the system demixes into two subsystems with different composition at sufficiently low temperatures and high densities.Comment: 10 pages, 6 figure

    PCN4 Costo-Efectividad De Octreotide Comparado Con Terapia De Soporte Usual Para El Tratamiento De Tumores Neuroendocrinos En Colombia

    Get PDF

    Additive manufacturing of 3D yttria-stabilized zirconia microarchitectures

    Get PDF
    The additive manufacturing (AM) of yttria-stabilized zirconia (YSZ) microarchitectures with sub-micrometer precision via two-photon lithography (TPL), utilizing custom photoresin containing zirconium and yttrium monomers is investigated. YSZ 3D microarchitectures can be formed at low temperatures (600 °C). The low-temperature phase stabilization of ZrO2 doped with Y2O3 demonstrates that doping ZrO2 with ≈ 10 mol% Y2O3 stabilizes the c-ZrO2 phase. The approach does not utilize YSZ particles as additives. Instead, the crystallization of the YSZ phase is initiated after printing, i.e., during thermal processing in the air at 600 °C – 1200 °C for one and two hours. The YSZ microarchitectures are characterized in detail. This includes understanding the role of defect chemistry, which has been overlooked in TPL-enabled micro-ceramics. Upon UV excitation, defect-related yellowish-green emission is observed from YSZ microarchitectures associated with intrinsic and extrinsic centers, correlated with the charge compensation due to Y3+ doping. The mechanical properties of the microarchitectures are assessed with manufactured micropillars. Micropillar compression yields the intrinsic mechanical strength of YSZ. The highest strength is observed for micropillars annealed at 600 °C, and this characteristic decreased with an increase in the annealing temperature. The deformation behavior gradually changes from ductile to brittle-like, correlating with the Hall–Petch strengthening mechanism.</p

    Photochromic mechanism in oxygen-containing yttrium hydride thin films: An optical perspective

    Get PDF
    Oxygen-containing yttrium hydride thin films exhibit photochromic behavior: Transparent thin films reversibly switch from a transparent state to a photodarkened state after being illuminated with UV or blue light. From optical spectrophotometry and ellipsometry measurements of the transparent state and photodarkened state, it is concluded that the photochromic effect can be explained by the gradual growth, under illumination, of metallic domains within the initial wide-band-gap semiconducting lattice. This conclusion is supported by Raman measurements

    Un estudi sobre interdisciplinarietat, professions socials i acció socioeducativa

    Get PDF
    Aquest article és el relat d'un seguit d'accions encetades per donar resposta a una serie de preguntes referides a l'àmbit de la intervenció socioeducativa. El que volíem era conèixer I'estat de la interdisciplinarietat en I'àmbit de les accions socioeducatives professionals. En quin grau i de quina manera conflueixen les diferents disc iplines en I'acció social o socioeducativa? Quines professions i professionals d'alló social van desenvolupant aquestes accions? Quines relacions -de col·laboració; de confrontació; d'aïllament, etc.- es produeixen entre elles? I, per últim, ens preguntàvem: existeix una consciència entre els i les professionals sobre la necessitat -o no- d'aquesta interdisciplinarietat

    The informal social support for autonomy and dependence in pain inventory Spanish version

    Get PDF
    Social support plays a crucial role in the quality of life of people with chronic pain. The Informal Social Support for Autonomy and Dependence in Pain Inventory assesses two functions of received social support: the promotion of autonomy and the promotion of dependence. The aim of this cross-sectional study was to adapt this instrument for its use in the Spanish population. The sample comprised 256 individuals with chronic pain. Participants were recruited through two local associations of people with fibromyalgia, a physiotherapy unit and a hospital pain unit. The data were collected in Spain between October 2018 and January 2020. The structure of the questionnaire was analysed using confirmatory factor analysis, average variance extracted, composite reliability and internal consistency indexes, and inter-correlations between the scales. The criterion-related validity of the instrument was analysed by investigating its relationship with pain intensity, positive and negative affect, daily functioning, activity impairment, wellbeing and satisfaction with life. The structure with the best fit had four related factors: emotional social support for the promotion of autonomy; instrumental social support for the promotion of autonomy; emotional social support for the promotion of dependence and instrumental social support for the promotion of dependence. The scales showed adequate internal consistency. An association was found between higher levels of instrumental social support for the promotion of dependence and higher levels of pain-related disability and decreased daily functioning. An association was also found between the promotion of autonomy and increased satisfaction with life. The Spanish version of the inventory shows appropriate psychometric properties. In the setting of disability prevention, this instrument is useful in assessing the support relationships between people with chronic pain and their relatives.info:eu-repo/semantics/publishedVersio

    The intensity of physical activity improves cognitive performance among aging Americans

    Get PDF
    Background: Currently there is no pharmacological cure for Alzheimer’s disease and related dementias, physical activity (PA) has emerged as a promising approach. The optimal intensity of PA to improve cognitive health remains unknown. Therefore, this study aimed to evaluate associations between different durations and intensities of PA on performance across cognitive domains (executive function, processing speed, and memory) among aging Americans. Methods: 2377 adults aged ≥ 60 years from the cross-sectional National Health and Nutrition Examination Survey 2011-2014, were included. Linear regression in hierarchical blocks and the size of effect (η2) were analyzed with R software. Results: The mean age was 69.3±6.73, 50.86% females. Despite the attenuation of association following adjustments for covariates, participants who engaged in 3-6 hr/wk of vigorous- and \u3e 1 hr/wk of moderate-intensity PA performed significantly higher in executive function and processing speed tests compared to inactive peers (η2= 0.005 & 0.007 respectively, p \u3c 0.05). However, there was no clear dose-response relationship between the executive function and processing speed test scores and duration of weekly moderate-intensity PA. For the adjusted model, the effects of 1-3 hr/wk of vigorous-intensity PA became trivial for the delayed recall memory test scores (β=0.33; 95% CI: -0.01, 0.67; η2=0.002; p=0.56). Interestingly, higher handgrip strength and higher late-life body-mass-index were associated with a higher performance across all cognitive domains. Conclusion: Observed associations provide evidence linking habitual PA with superior cognition health among older adults. Furthermore, increased muscle strength and higher late-life adiposity may impact cognition and require further investigation

    Oxygen vacancy related distortions in rutile TiO_2 nanoparticles: a combined experimental and theoretical study

    Get PDF
    The effects of doubly ionized oxygen vacancies [(V_O)ˆ(2+)]on the electronic structure and charge distribution in rutile TiO_2 are studied by combining first-principles calculations based on density functional theory and experimental results from x-ray photoelectron and x-ray absorption measurements carried out in synchrotron facilities on rutile TiO_2 nanoparticles. The generalized gradient approximation of the Perdew-Burke-Ernzerhof functional has demonstrated its suitability for the analysis of the [(V_O)ˆ(2+)]defects in rutile TiO_2. It has been found that the presence of empty electronic states at the conduction band shifted ̴1 eV from t_(2g) and e_(g) states can be associated with local distortions induced by [(V_O)ˆ(2+)]defects, in good agreement with Gauss-Lorentzian band deconvolution of experimental O K-edge spectra. The asymmetry of t(2g) and e(g) bands at the O-K edge has been associated with [(V_O)ˆ(2+)], which can enrich the understanding of studies where the presence of these defects plays a key role, as in the case of doped TiO_2

    A global perspective on the influence of environmental exposures on the nervous system

    Get PDF
    Economic transitions in the era of globalization warrant a fresh look at the neurological risks associated with environmental change. These are driven by industrial expansion, transfer and mobility of goods, climate change and population growth. In these contexts, risk of infectious and non-infectious diseases are shared across geographical boundaries. In low- and middle-income countries, the risk of environmentally mediated brain disease is augmented several fold by lack of infrastructure, poor health and safety regulations, and limited measures for environmental protection. Neurological disorders may occur as a result of direct exposure to chemical and/or non-chemical stressors, including but not limited to, ultrafine particulate matters. Individual susceptibilities to exposure-related diseases are modified by genetic, epigenetic and metagenomic factors. The existence of several uniquely exposed populations, including those in the areas surrounding the Niger Delta or north western Amazon oil operations; those working in poorly regulated environments, such as artisanal mining industries; or those, mostly in sub-Saharan Africa, relying on cassava as a staple food, offers invaluable opportunities to advance the current understanding of brain responses to environmental challenges. Increased awareness of the brain disorders that are prevalent in low- and middle-income countries and investments in capacity for further environmental health-related research are positive steps towards improving human health

    Relationship Between Cognitive Performance, Physical Activity, and Socio-Demographic/Individual Characteristics Among Aging Americans

    Get PDF
    Background: Physical activity (PA) has emerged as a promising approach to delay Alzheimer’s disease and related dementias, but the optimal intensity of PA to improve cognitive health remains unknown. Objective: To evaluate the association between duration and intensity of PA and cognitive domains (executive function, processing speed, and memory) in aging Americans. Methods: Linear regressions in hierarchical blocks for variable adjustment and the size of effect (η2) were analyzed by using the data of 2,377 adults (age = 69.3±6.7 years) from the NHANES 2011–2014. Results: Participants with 3–6 h/week of vigorous- and \u3e 1 h/week of moderate-intensity PA scored significantly higher in executive function and processing speed domains of cognition compared to inactive peers (η2 = 0.005 & 0.007 respectively, p \u3c 0.05). After adjustment, the beneficial effects of 1–3 h /week of vigorous-intensity PA became trivial for delayed recall memory domain test scores (η2 = 0.33; 95%CI: –0.01,0.67; η2 = 0.002; p = 0.56). There was no linear dose-response relationship between the cognitive test scores and weekly moderate-intensity of PA. Interestingly, higher handgrip strength and higher late-life body mass index were associated with a higher performance across all cognitive domains. Conclusion: Our study supports habitual PA with superior cognition health in some but not all domains among older adults. Furthermore, increased muscle strength and higher late-life adiposity may also impact cognition
    corecore