First-Principles Study of the Electronic and Magnetic Properties of Defects in Carbon Nanostructures

Understanding the magnetic properties of graphenic nanostructures is instrumental in future spintronics applications. These magnetic properties are known to depend crucially on the presence of defects. Here we review our recent theoretical studies using density functional calculations on two types of defects in carbon nanostructures: Substitutional doping with transition metals, and sp$^3$-type defects created by covalent functionalization with organic and inorganic molecules. We focus on such defects because they can be used to create and control magnetism in graphene-based materials. Our main results are summarized as follows: i)Substitutional metal impurities are fully understood using a model based on the hybridization between the $d$ states of the metal atom and the defect levels associated with an unreconstructed D$_{3h}$ carbon vacancy. We identify three different regimes, associated with the occupation of distinct hybridization levels, which determine the magnetic properties obtained with this type of doping; ii) A spin moment of 1.0 $\mu_B$ is always induced by chemical functionalization when a molecule chemisorbs on a graphene layer via a single C-C (or other weakly polar) covalent bond. The magnetic coupling between adsorbates shows a key dependence on the sublattice adsorption site. This effect is similar to that of H adsorption, however, with universal character; iii) The spin moment of substitutional metal impurities can be controlled using strain. In particular, we show that although Ni substitutionals are non-magnetic in flat and unstrained graphene, the magnetism of these defects can be activated by applying either uniaxial strain or curvature to the graphene layer. All these results provide key information about formation and control of defect-induced magnetism in graphene and related materials.Comment: 40 pages, 17 Figures, 62 References; Chapter 2 in Topological Modelling of Nanostructures and Extended Systems (2013) - Springer, edited by A. R. Ashrafi, F. Cataldo, A. Iranmanesh, and O. Or

Rate and duration of hospitalisation for acute pulmonary embolism in the real-world clinical practice of different countries : Analysis from the RIETE registry

publishersversionPeer reviewe

Effect of a mediterranean diet intervention on dietary glycemic load and dietary glycemic index: the predimed study

Objective. To compare the one year effect of two dietary interventions with MeDiet on GL and GI in the PREDIMED trial. Methods. Participants were older subjects at high risk for cardiovascular disease. This analysis included 2866 nondiabetic subjects. Diet was assessed with a validated 137-item food frequency questionnaire (FFQ). The GI of each FFQ item was assigned by a 5-step methodology using the International Tables of GI and GL Values. Generalized linear models were fitted to assess the relationship between the intervention group and dietary GL and GI at one year of follow-up, using control group as reference. Results. Multivariate-adjusted models showed an inverse association between GL and MeDiet + extra virgin olive oil (EVOO) group: β = -8.52 (95% CI: -10.83 to -6.20) and MeDiet + Nuts group: β = -10.34 (95% CI: -12.69 to -8.00), when comparing with control group. Regarding GI, β = -0.93 (95% CI: -1.38 to -0.49) for MeDiet + EVOO, β = -1.06 (95% CI: -1.51 to -0.62) for MeDiet + Nuts when comparing with control group. Conclusion. Dietary intervention with MeDiet supplemented with EVOO or nuts lowers dietary GL and GI

Adipose Tissue Redox Microenvironment as a Potential Link between Persistent Organic Pollutants and the 16-Year Incidence of Non-hormone-Dependent Cancer

[Image: see text] We aimed to assess the relationships among the adipose tissue’s (AT) oxidative microenvironment, in situ accumulated persistent organic pollutant (POP) concentrations, and cancer development. POP and oxidative stress levels were quantified in AT samples from 382 adults recruited within the GraMo cohort (2003–2004) in Granada (Spain). The 16-year cancer incidence was ascertained by reviewing health/administrative databases. Cox-regression models and mediation analyses were performed. The enzymes superoxide dismutase (SOD) and glutathione reductase (GRd) were positively associated with the risk of non-hormone-dependent (NHD) cancer [adjusted hazard ratio (HR) 1.76; 95% confidence interval (CI): 1.17, 2.64 and HR 2.35; 95% CI: 1.41, 3.94, respectively]. After adjustment for covariates, polychlorinated biphenyl-138 (PCB-138) (HR 1.78; 95% CI: 1.03, 3.09), β-hexachlorocyclohexane (β-HCH) (HR 1.70; 95% CI: 1.09, 2.64), and hexachlorobenzene (HR 1.54; 95% CI: 1.02, 2.33) were also positively associated with the risk of NHD cancer. Although confidence intervals included the null value, probably because of the modest number of cancer cases, we observed a potential mediation effect of SOD and GRd on the associations between β-HCH and the risk of NHD tumors (percent mediated = 33 and 47%, respectively). Our results highlight the relevance of human AT’s oxidative microenvironment as a predictor of future cancer risk as well as its potential mediating role on POP-related carcinogenesis. Given their novelty, these findings should be interpreted with caution and confirmed in future studies

Impact of intestinal dysbiosis-related drugs on the efficacy of immune checkpoint inhibitors in clinical practice

[Purpose]: Intestinal dysbiosis has emerged as a biomarker of response to immune checkpoint inhibitors (ICIs). It can be caused by antibiotics, although it may also result from the use of other drugs that have been studied to a lesser extent. The objective of our study was to analyze the association between the use of potentially dysbiosis-related drugs and survival in patients treated with ICIs in the clinical practice.[Materials and methods]: A retrospective, multicenter, cohort study was conducted. Clinicopathological variables were collected and the concomitant use of drugs was analyzed. A descriptive analysis of variables and overall survival, estimated by the Kaplan–Meier method, was performed, and association with various independent variables was assessed using Cox regression.[Results]: We included 253 patients, mainly with non-small cell lung cancer and melanoma. The most commonly used drugs were acid reducers, prescribed to 55.3% of patients, followed by corticosteroids (37.9%), anxiolytic drugs (35.6%), and antibiotics (20.5%). The use of acid reducers (9 vs. 18 months, P < .0001), antibiotics (7 vs. 15 months, P < .017), anxiolytic drugs (8 vs. 16 months, P < .015), and corticosteroids (6 vs. 19 months, P < .00001) was associated with poorer overall survival. Furthermore, the greater the number of drugs used concomitantly with ICIs, the higher the risk of death (1 drug: hazard ratio, 1.88; CI 95%, 1.07–3.30; 4 drugs: hazard ratio, 4.19; CI9 5%, 1.77–9.92; P < .001).[Conclusion]: Response to ICIs may be influenced by the use of drugs that lead to intestinal dysbiosis. Although a confirmatory prospective controlled study is required, our findings should be taken into account when analyzing ICI efficacy