99 research outputs found

    Surface Electron-Hole Rich Species Active in the Electrocatalytic Water Oxidation

    Get PDF
    Iridium and ruthenium and their oxides/hydroxides are the best candidates for the oxygen evolution reaction under harsh acidic conditions owing to the low overpotentials observed for Ru- and Ir-based anodes and the high corrosion resistance of Ir-oxides. Herein, by means of cutting edge operando surface and bulk sensitive X-ray spectroscopy techniques, specifically designed electrode nanofabrication and ab initio DFT calculations, we were able to reveal the electronic structure of the active IrOx centers (i.e., oxidation state) during electrocatalytic oxidation of water in the surface and bulk of high-performance Ir-based catalysts. We found the oxygen evolution reaction is controlled by the formation of empty Ir 5d states in the surface ascribed to the formation of formally IrV species leading to the appearance of electron-deficient oxygen species bound to single iridium atoms (μ1-O and μ1-OH) that are responsible for water activation and oxidation. Oxygen bound to three iridium centers (μ3-O) remains the dominant species in the bulk but do not participate directly in the electrocatalytic reaction, suggesting bulk oxidation is limited. In addition a high coverage of a μ1-OO (peroxo) species during the OER is excluded. Moreover, we provide the first photoelectron spectroscopic evidence in bulk electrolyte that the higher surface-to-bulk ratio in thinner electrodes enhances the material usage involving the precipitation of a significant part of the electrode surface and near-surface active species

    The insulin-like growth factor system is modulated by exercise in breast cancer survivors: a systematic review and meta-analysis

    Get PDF
    Abbreviations: CI, Confidence interval; ELISA, Enzyme-linked immunosorbent assay; IGF, Insulin-like growth factors; IGFBP, Insulin-like growth factor binding protein; MD, Mean difference; PEDro, Physiotherapy evidence database; RCT, Randomized controlled trials; SD, Standard deviation.Background: Insulin-like growth factors (IGF´s) play a crucial role in controlling cancer cell proliferation, differentiation and apoptosis. Exercise has been postulated as an effective intervention in improving cancerrelated outcomes and survival, although its effects on IGF´s are not well understood. This meta-analysis aimed to determine the effects of exercise in modulating IGF´s system in breast cancer survivors. Methods: Databases of PuMed, EMBASE, Cochrane Central Register of Controlled Trials, EMBASE, ClinicalTrials. gov, SPORTDiscus, LILACS and Scopus were systematically searched up to November 2014. Effect estimates were calculated through a random-effects model of meta-analysis according to the DerSimonian and Laird method. Heterogeneity was evaluated with the I2 test. Risk of bias and methodological quality were evaluated using the PEDro score. Results: Five randomized controlled trials (n = 235) were included. Most women were post-menopausal. Highquality and low risk of bias were found (mean PEDro score = 6.2 ± 1). Exercise resulted in significant improvements on IGF-I, IGF-II, IGFBP-I, IGFBP-3, Insulin and Insulin resistance (P < 0.05). Non-significant differences were found for Glucose. Aerobic exercise improved IGF-I, IGFBP-3 and Insulin. No evidence of publication bias was detected by Egger´s test (p = 0.12). Conclusions: Exercise improved IGF´s in breast cancer survivors. These findings provide novel insight regarding the molecular effects of exercise on tumoral microenvironment, apoptosis and survival in breast cancer survivors

    Search for Dark Matter Annihilation in the Galactic Center with IceCube-79

    Get PDF
    The Milky Way is expected to be embedded in a halo of dark matter particles, with the highest density in the central region, and decreasing density with the halo-centric radius. Dark matter might be indirectly detectable at Earth through a flux of stable particles generated in dark matter annihilations and peaked in the direction of the Galactic Center. We present a search for an excess flux of muon (anti-) neutrinos from dark matter annihilation in the Galactic Center using the cubic-kilometer-sized IceCube neutrino detector at the South Pole. There, the Galactic Center is always seen above the horizon. Thus, new and dedicated veto techniques against atmospheric muons are required to make the southern hemisphere accessible for IceCube. We used 319.7 live-days of data from IceCube operating in its 79-string configuration during 2010 and 2011. No neutrino excess was found and the final result is compatible with the background. We present upper limits on the self-annihilation cross-section, \left, for WIMP masses ranging from 30 GeV up to 10 TeV, assuming cuspy (NFW) and flat-cored (Burkert) dark matter halo profiles, reaching down to 41024\simeq 4 \cdot 10^{-24} cm3^3 s1^{-1}, and 2.61023\simeq 2.6 \cdot 10^{-23} cm3^3 s1^{-1} for the νν\nu\overline{\nu} channel, respectively.Comment: 14 pages, 9 figures, Submitted to EPJ-C, added references, extended limit overvie

    Clinical trial to assess the effect of physical exercise on endothelial function and insulin resistance in pregnant women

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Preeclampsia (PE) is a common maternal disease that complicates 5 to 10% of pregnancies and remains as the major cause of maternal and neonatal mortality. Cost-effective interventions aimed at preventing the development of preeclampsia are urgently needed. However, the pathogenesis of PE is not well known. Multiple mechanisms such as oxidative stress, endothelial dysfunction and insulin resistance may contribute to its development. Regular aerobic exercise recovers endothelial function; improves insulin resistance and decreases oxidative stress. Therefore the purpose of this clinical trial is to determine the effect of regular aerobic exercise on endothelial function, on insulin resistance and on pregnancy outcome.</p> <p>Methods and design</p> <p>64 pregnant women will be included in a blind, randomized clinical trial, and parallel assignment. The exercise group will do regular aerobic physical exercise: walking (10 minutes), aerobic exercise (30 minutes), stretching (10 minutes) and relaxation exercise (10 minutes) in three sessions per week. Control group will do the activities of daily living (bathing, dressing, eating, and walking) without counselling from a physical therapist.</p> <p>Trial registration</p> <p>NCT00741312.</p

    Eficácia do exercício físico na fadiga dos pacientes com câncer durante o tratamento ativo: revisão sistemática e meta-análise

    Get PDF
    El objetivo del estudio fue determinar la efectividad del ejercicio físico en la fatiga de pacientes con cáncer durante el tratamiento activo. Las bases de datos de PubMed Central, EMBASE y OVID fueron consultadas hasta abril de 2014 para identificar ensayos clínicos aleatorizados, que evaluaran el efecto del ejercicio en la fatiga de pacientes con cáncer sometidos a tratamiento activo. Once estudios (n = 1.407) fueron incluidos. La quimioterapia fue el tratamiento más común (n = 1.028). Los estudios tuvieron bajo riesgo de sesgo y alta calidad metodológica. Las estimaciones de efecto mostraron que el ejercicio físico mejoró significativamente la fatiga (SMD = -3,0; IC95%: -5,21; -0,80), p < 0,0001. Se encontraron efectos similares para el entrenamiento de resistencia (SMD = -4,5; IC95%: -7,24; -1,82), p = 0,001. Se encontraron mejoras significativas en pacientes con cáncer de mama y de próstata (p < 0,05). El ejercicio es una intervención segura y eficaz en el control de la fatiga en pacientes sometidos a tratamiento activoThis study aimed to determine the effectiveness of physical exercise in decreasing fatigue in cancer patients during active treatment. The PubMed Central, EMBASE, and OVID databases were consulted up to April 2014 to identify randomized clinical trials that evaluated the effect of exercise on fatigue in cancer patients undergoing active treatment. Eleven studies (n = 1,407) were included. Chemotherapy was the most common form of treatment (n = 1,028). The studies showed a low risk of bias and high methodological quality. Effect estimates showed that physical exercise significantly improved fatigue (SMD = -3.0; 95%CI: -5.21; -0.80), p < 0.0001. Similar effects were found for resistance training (SMD = -4.5; 95%CI: -7.24; -1.82), p = 0.001. Significant improvements were found in breast and prostate cancer patients (p < 0.05). Exercise is a safe and effective intervention in the management fatigue in cancer patients undergoing active treatmentO objetivo foi determinar a efetividade do exercício físico sobre a fadiga em pacientes com câncer durante o tratamento ativo. As bases de dados PubMed Central, EMBASE e OVID foram consultadas até abril de 2014 para identificar ensaios clínicos randomizados que avaliaram o efeito do exercício sobre a fadiga em pacientes com câncer em tratamento ativo. Onze estudos (n = 1.407) foram incluídos. A quimioterapia foi o tratamento mais comum (n = 1.028). Os estudos tiveram baixo risco de viés e alta qualidade metodológica. As estimativas de efeito mostraram que o exercício melhorou significativamente a fadiga (DMP = -3,0; IC95%: -5,21; -0,80), p < 0,0001. Efeitos semelhantes sobre o treinamento de resistência (DMP = -4,5; IC95%: -7,24; -1,82), p = 0,001 foram encontrados. O exercício físico é uma intervenção segura e eficaz contra a fadiga em pacientes submetidos ao tratamento ativoEl presente trabajo forma parte del Proyecto Práctica del autoexamen de seno y los conocimientos, factores de riesgo y estilos de vida relacionados con el cáncer de mama en mujeres jóvenes de la Universidad Santo Tomás de Bogotá: un análisis transversal (9ª Convocatoria FODEIN- Código del proyecto 4110060001 - 008)

    Effects of supervised exercise on cancer-related fatigue in breast cancer survivors: a systematic review and meta-analysis

    Get PDF
    Background: Cancer-related fatigue (CRF) is the most common and distressing symptom in breast cancer survivors. Approximately 40% to 80% of cancer patients undergoing active treatment suffer from CRF. Exercise improves overall quality of life and CRF; however, the specific effects of the training modalities are not well understood.Methods: This study aimed to determine the pooled effects of supervised exercise interventions on CRF in breast cancer survivors. We searched PubMed/MEDLINE, EMBASE, Scopus, CENTRAL and CINAHL databases between December 2013 and January 2014 without language restrictions. Risk of bias and methodological quality were evaluated using the PEDro score. Pooled effects were calculated with a random-effects model according to the DerSimonian and Laird method. Heterogeneity was evaluated with the I2 test.Results: Nine high-quality studies (n = 1156) were finally included. Supervised aerobic exercise was statistically more effective than conventional care in improving CRF among breast cancer survivors (SMD = −0.51, 95%CI −0.81 to −0.21), with high statistical heterogeneity (P = 0.001; I2 = 75%). Similar effects were found for resistance training on CRF (SMD = −0.41, 95%CI −0.76 to −0.05; P = 0.02; I2 = 64%). Meta-regression analysis revealed that exercise volume parameters are closely related with the effect estimates on CRF. Egger’s test suggested moderate evidence of publication bias (P = 0.04).Conclusions: Supervised exercise reduces CRF and must be implemented in breast cancer rehabilitation settings. High-volume exercises are safe and effective in improving CRF and overall quality of life in women with breast cancer. Further research is encouraged.The authors would like to acknowledge Universidad Santo Tomás, Bogotá for the financial support to the GICAEDS Group (Project: Práctica del autoexamen de seno y los conocimientos, factores de riesgo y estilos de vida relacionados al cáncer de mama en mujeres jóvenes de la USTA – Number: 4110060001-008)

    Self-organization of developing embryo using scale-invariant approach

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Self-organization is a fundamental feature of living organisms at all hierarchical levels from molecule to organ. It has also been documented in developing embryos.</p> <p>Methods</p> <p>In this study, a scale-invariant power law (SIPL) method has been used to study self-organization in developing embryos. The SIPL coefficient was calculated using a centro-axial skew symmetrical matrix (CSSM) generated by entering the components of the Cartesian coordinates; for each component, one CSSM was generated. A basic square matrix (BSM) was constructed and the determinant was calculated in order to estimate the SIPL coefficient. This was applied to developing <it>C. elegans </it>during early stages of embryogenesis. The power law property of the method was evaluated using the straight line and Koch curve and the results were consistent with fractal dimensions (fd). Diffusion-limited aggregation (DLA) was used to validate the SIPL method.</p> <p>Results and conclusion</p> <p>The fractal dimensions of both the straight line and Koch curve showed consistency with the SIPL coefficients, which indicated the power law behavior of the SIPL method. The results showed that the ABp sublineage had a higher SIPL coefficient than EMS, indicating that ABp is more organized than EMS. The fd determined using DLA was higher in ABp than in EMS and its value was consistent with type 1 cluster formation, while that in EMS was consistent with type 2.</p
    corecore