Density functional study of the magnetic properties of Bi4Mn clusters: Discrepancy between theory and experiment

We have performed collinear and noncollinear calculations on neutral Bi4Mn and collinear ones on ionized Bi4Mn with charges +1 and −1 to find out why theoretical calculations will not predict the magnetic state found in the experiment. We have used the density functional theory to find a fit between the theoretical prediction of the magnetic moment and the experimental value. Our calculations have consisted in a structural search of local energy minima, and the lowest energy magnetic state for each resulting isomer. The geometry optimization found three local minima whose fundamental state is the doublet spin state. These isomers could not be found in previous theoretical works, but they are higher in energy than the lowest-lying isomer by ≈1.75 eV. This magnetic state could help understand the experiment. Calculations of noncollinear magnetic states for the Bi4Mn do not lower the total magnetic moment. We conclude arguing how the three isomers with doublet state could actually be the ones measured in the experimentThis research has been done under the Projects No. MAT2009-08165 and No. INCITE08PXIB236052PR. One of the authors has been enjoying financial support from the Isabel Barreto programS

Effects of applied pressure in ZnV2 O4 and evidences for a dimerized structure

The series of V spinels [A2+] V2 O4 (A = Cd, Mn, Zn, Mg) provides an opportunity to tune the V-V distance continuously, in the frustrated pyrochlore lattice of the spinel. This system has been shown to approach the metallic state when V-V distance is reduced. The proximity to the transition leads to a dimerized structure in ZnV2 O4 caused by lattice instabilities. A different manner to tune the V − V distance of this structure is to fix the A2+ cation (in our case, Zn) and apply pressure. We have analyzed the evolution of the electronic structure of the system in the dimerized state. Such structure prevents the system to present a metallic phase at moderate pressures. We have also calculated the transport properties in a semiclassical approach based on Boltzmann transport theory. Our results support the validity of this structural distortion by providing a nice fit with experimental measurementsThe authors thank the CESGA (Centro de Supercomputacion de Galicia) for the computing facilities and the Ministerio de Educación y Ciencia (MEC) for the financial support through the project MAT2009-08165. A.S.B. thanks MEC for an FPU grant. J.B. and M.P. acknowledge Deputación da Coruña and the Isabel Barreto program respectively for financial support. We are also thankful to the Xunta de Galicia for financial support through the project INCITE08PXIB236052PRS

Cognitive frailty: a conceptual systematic review and an operational proposal for future research

[Abstract] Objective. To analyze the definition of “cognitive frailty” and to study the conceptual and operational definitions used and their implications for empirical research. The relationships between this concept and cognitive reserve, the role of neuropathology and brain reserve, motor signs of aging and the reversibility of cognitive frailty are also discussed. Study design. Systematic review of empirical studies identified from Medline Advanced 1966, CINAHL, Web of Science, PsycINFO, and Scopus until August 2017. Main – outcome measures. Effect sizes. The quality of the articles was assessed by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Statement. Three independent reviewers participated in the study selection and data extraction. Results. Nineteen studies involving 31,707 participants met the inclusion criteria. Significant associations were reported between cognitive frailty and physical frailty or gait speed. Screening instruments were usually used to determine objective cognitive decline rather than extensive neuropsychological assessments. Educational level was the only indicator of cognitive reserve that was systematically included in the evaluation of cognitive frailty. Motor decline and gait variables were not systematically included in protocols for the assessment of cognitive frailty. Conclusions. A strong operational definition would benefit both the development of treatments to counter cognitive frailty and the assessment of treatment effectiveness. Nevertheless, since there is clear agreement regarding the importance of interventions for and the prevention of cognitive frailty, randomized controlled trials investigating the efficacy of preventive interventions are necessary.Xunta de Galicia; ED431C-2017/27Xunta de Galicia; ED431C 2017/49Xunta de Galicia; ED431F 2017/09Xunta de Galicia; IN607C 2016/0

The coagulation system helps control infection caused by the ciliate parasite Philasterides dicentrarchi in the turbot Scophthalmus maximus (L.)

This is the accepted manuscript of the following article: Blanco-Abad, V., Noia, M., Valle, A., Fontenla, F., Folgueira, I., & De Felipe, A. et al. (2018). The coagulation system helps control infection caused by the ciliate parasite Philasterides dicentrarchi in the turbot Scophthalmus maximus (L.). Developmental & Comparative Immunology, 87, 147-156. doi: 10.1016/j.dci.2018.06.001Many studies have shown that coagulation systems play an important role in the defence against pathogens in invertebrates and vertebrates. In vertebrates, particularly in mammals, it has been established that the coagulation system participates in the entrapment of pathogens and activation of the early immune response. However, functional studies investigating the importance of the fish coagulation system in host defence against pathogens are scarce. In the present study, injection of turbot (Scopthalamus maximus) with the pathogenic ciliate Philasterides dicentrarchi led to the formation of macroscopic intraperitoneal clots in the fish. The clots contained abundant, immobilized ciliates, many of which were lysed. We demonstrated that the plasma clots immobilize and kill the ciliates in vitro. To test the importance of plasma clotting in ciliate killing, we inhibited the process by adding a tetrapeptide known to inhibit fibrinogen/thrombin clotting in mammals. Plasma tended to kill P. dicentrarchi slightly faster when clotting was inhibited by the tetrapeptide, although the total mortality of ciliates was similar. We also found that kaolin, a particulate activator of the intrinsic pathway in mammals, accelerates plasma clotting in turbot. In addition, PMA-stimulated neutrophils, living ciliates and several ciliate components such as cilia, proteases and DNA also displayed procoagulant activity in vitro. Injection of fish with the ciliates generated the massive release of neutrophils to the peritoneal cavity, with formation of large aggregates in those fish with live ciliates in the peritoneum. We observed, by SEM, numerous fibrin-like fibres in the peritoneal exudate, many of which were associated with peritoneal leukocytes and ciliates. Expression of the CD18/CD11b gene, an integrin associated with cell adhesion and the induction of fibrin formation, was upregulated in the peritoneal leukocytes. In conclusion, the findings of the present study show that P. dicentrarchi induces the formation of plasma clots and that the fish coagulation system may play an important role in immobilizing and killing this parasiteThis work was financially supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 634429 (PARAFISHCONTROL), by the Ministerio de Economía y Competitividad (Spain) under grant agreement AGL2014-57125-R and by grant GPC2014/069 from the Xunta de Galicia (Spain)S

La prevención del consumo de drogas y la conducta antisocial en la escuela: Análisis y evaluación de un programa

Ministerio de Educación y Cultura Ministerio de Sanidad y Consumo Ministerio del Interio

Electronic structure analysis of the quasi-one-dimensional oxide Sr6Co5O15 within the LDA+U method

The quasi-one-dimensional cobalt oxide Sr6Co5O15 is studied using first-principles electronic-structure calculations and Boltzmann transport theory. We have been able to describe the electronic structure, characterized by the structural one-dimensionality and a particular type of charge ordering, with unexpected electronic structure of the different Co atoms. The origin of the large unquenched misaligned orbital angular momenta comes out naturally from a correct description of the different crystal-field environments. The evolution with the on-site Coulomb repulsion (U) of the electronic structure and the transport properties is discussed, with a best agreement with experiment found for the smallest value of U that allows to converge the correct in-chain ferrimagnetic ground stateThe authors thank the CESGA for the computing facilities, the Ministerio de Educación y Ciencia (MEC) for the financial support through the project MAT2009-08165, the Ministerio de Ciencia e Innovación (MICINN) for the project MAT2007-60536 and the Xunta de Galicia for the project INCITE08PXIB236052PR. A.S.B. thanks MEC for a FPU grant. M.P. and J.B. thank Isabel Barreto program and Deputación da Coruña, respectively, for financial supportS

La pesca y la acuicultura en la protección de los ecosistemas marinos

Versión del editor

Rag1 immunodeficiency‐induced early aging and senescence in zebrafish are dependent on chronic inflammation and oxidative stress [Poster]

12th European Zebrafish Meeting, Krakow, 9-13 July 2023In mammals, recombination activating gene 1 (RAG1) plays a crucial role in adaptive immunity, generating a vast range of immunoglobulins. Rag1−/− zebrafish (Danio rerio) are viable and reach adulthood without obvious signs of infectious disease in standard nonsterile conditions, suggesting that innate immunity could be enhanced to compensate for the lack of adaptive immunity. By using microarray analysis, we confirmed that the expression of immunity- and apoptosis-related genes was increased in the rag1−/− fish. This tool also allows us to notice alterations of the DNA repair and cell cycle mechanisms in rag1−/− zebrafish. Several senescence and aging markers were analyzed. In addition to the lower lifespan of rag1−/− zebrafish compared to their wild-type (wt) siblings, rag1−/− showed a higher incidence of cell cycle arrest and apoptosis, a greater amount of phosphorylated histone H2AX, oxidative stress and decline of the antioxidant mechanisms, an upregulated expression and activity of senescence-related genes and senescence-associated β-galactosidase, respectively, diminished telomere length, and abnormal self-renewal and repair capacities in the retina and liver. Metabolomic analysis also demonstrated clear differences between wt and rag1−/− fish, as was the deficiency of the antioxidant metabolite L-acetylcarnitine (ALCAR) in rag1−/− fish. Therefore, Rag1 activity does not seem to be limited to V(D)J recombination but is also involved in senescence and aging. Furthermore, we confirmed the senolytic effect of ABT-263, a known senolytic compound and, for the first time, the potential in vivo senolytic activity of the antioxidant agent ALCAR, suggesting that this metabolite is essential to avoid premature agingN