First-principles prediction of coexistence of magnetism and ferroelectricity in rhombohedral Bi2FeTiO6

First principles calculations based on the density functional theory within the local spin density approximation plus U(LSDA+U)scheme, show rhombohedral Bi$_2$FeTiO$_6$ is a potential multiferroic in which the magnetism and ferroelectricity coexist . A ferromagnetic configuration with magnetic moment of 4 $\mu_B$ per formula unit have been reported with respect to the minimum total energy. Spontaneous polarization of 27.3 $\mu$ C/cm$^2$, caused mainly by the ferroelectric distortions of Ti, was evaluated using the berry phase approach in the modern theory of polarization. The Bi-6s stereochemical activity of long-pair and the `d$^0$-ness' criterion in off-centring of Ti were coexisting in the predicted new system. In view of the oxidation state of Bi$^{3+}$,Fe$^{2+}$,Ti$^{4+}$, and O$^{2-}$ from the orbital-resolved density of states of the Bi-6p, Fe-3d,Ti-3d, and O-2p states,the valence state of Bi$_2$FeTiO$_6$ in the rhombohedral phase was found to be Bi$_2$$^{3+}$Fe$^{2+}$Ti$^{4+}$O$_6$.Comment: 22 pages, 9 figures. submitted to Physics Letters

Argumentation as Exogenous Coordination

Formal argumentation is one of the most popular approaches in modern logic and reasoning. The theory of abstract argumentation introduced by Dung in 1995 has shifted the focus from the internal structure of arguments to relations among arguments, and temporal dynamics for abstract argumentation was proposed by Barringer, Gabbay and Woods in 2005. In this tradition, we see arguments as reasoning processes, and the interaction among them as a coordination process.We argue that abstract argumentation can adopt ideas and techniques from formal theories of coordination, and as an example we propose a model of sequential abstract argumentation loosely inspired by Reo’s model of exogenous coordination. We show how the argumentation model can represent the temporal dynamics of the liar paradox and predator-prey like behaviour

HIV-1 Env associates with HLA-C free-chains at the cell membrane modulating viral infectivity

HLA-C has been demonstrated to associate with HIV-1 envelope glycoprotein (Env). Virions lacking HLA-C have reduced infectivity and increased susceptibility to neutralizing antibodies. Like all others MHC-I molecules, HLA-C requires \u3b22-microglobulin (\u3b22m) for appropriate folding and expression on the cell membrane but this association is weaker, thus generating HLA-C free-chains on the cell surface. In this study, we deepen the understanding of HLA-C and Env association by showing that HIV-1 specifically increases the amount of HLA-C free chains, not bound to \u3b22m, on the membrane of infected cells. The association between Env and HLA-C takes place at the cell membrane requiring \u3b22m to occur. We report that the enhanced infectivity conferred to HIV-1 by HLA-C specifically involves HLA-C free chain molecules that have been correctly assembled with \u3b22m. HIV-1 Env-pseudotyped viruses produced in the absence of \u3b22m are less infectious than those produced in the presence of \u3b22m. We hypothesize that the conformation and surface expression of HLA-C molecules could be a discriminant for the association with Env. Binding stability to \u3b22m may confer to HLA-C the ability to preferentially act either as a conventional immune-competent molecule or as an accessory molecule involved in HIV-1 infectivity

Impaired bone matrix glycoprotein pattern is associated with increased cardiometabolic risk profile in patients with type 2 diabetes mellitus

Purpose Osteopontin (OPN), osteoprotegerin (OPG) and osteocalcin (OC) are matrix glycoproteins which mediate bone mineralization; moreover, their effects on glucose/insulin homeostasis have recently been demonstrated. Higher circulating OPN and OPG levels have been associated with the presence of insulin resistance, atherosclerosis and coronary heart disease. No data are available on contextual changes of these markers in type 2 diabetes mellitus (T2DM). Therefore, aims of this study were to evaluate serum OPN, OPG and OC levels in T2DM patients and their clinical correlates. Methods We recruited 83 consecutive T2DM patients referring to our diabetes outpatient clinics at Sapienza, University of Rome, and 71 non-diabetic sex and age-comparable subjects as a control group. Study population underwent metabolic characterization and carotid ultrasound for intima–media thickness measurement. Plasma OPN, OPG and OC were measured by MILLIPLEX Multiplex Assays Luminex. Results T2DM patients had significantly higher circulating OPN and OPG levels than controls (14.3 ± 13.6 vs 10.6 ± 13.7 ng/ml p < 0.001, 0.70 ± 0.60 vs 0.54 ± 4.1 ng/ml, p = 0.02) while OC levels were similar in the two cohorts (6.35 ± 5.8 vs 7.80 ± 7.0 ng/ml, p = n.s). OPN and OPG positively correlated with greater systolic blood pressure (SBP) values, HOMA-IR and HOMA-β, and with the presence of dyslipidemia and carotid atherosclerosis. The association between greater OPN and OPG levels and SBP was independent from possible confounders (both p = 0.01). Conclusions Circulating OPN and OPG levels are increased in T2DM patients and identify a particularly unfavourable metabolic profile, mostly expressed by higher SBP. Bone peptides may represent novel markers of vascular stress and accelerated atherosclerosis in diabetes, constituting a possible tool for cardiovascular risk stratification in diabetes

Seasonal Variation of the Volatile Constituents from Leaves of Pimenta pseudocaryophyllus (Gomes)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The chemical variation of volatile constituents from leaves of Pimenta pseudocaryophyllus collected bimonthly for one year from a locality in the Atlantic Rain Forest, southeastern Brazil, was determined by GC/MS. Seven compounds were identified and characterized, revealing a predominance of phenylpropanoids (15.4-70.9%) and variable amounts of monoterpenes (0.5-5.3%). The composition of the oil changed month by month. The best yield of oil was obtained in November, and the major component chavibetol was present in all samples (50.2-70.9%). The chavibetol content showed significant seasonal variation, with the maximum percentages of 69.1% and 70.9% measured in January and November, respectively.2345457Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundacao AraucariaCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Composition of Leaf and Rhizome Essential Oils of Hedychium coronarium Koen. from Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Hydrodistillation of fresh leaves and rhizomes of Hedychium coronarium collected in the Atlantic rain forest of southeastern Brazil afforded essential oils in 0.68% and 0.20% yields, respectively. Analysis of the oils by GC and GC/MS revealed as predominant constituents in the leaf oil beta-caryophyllene (43.0%), caryophyllene oxide (12.1%) and beta-pinene (11.6%,), whereas 1,8-cineole (34.8%), beta-pinene (16.7%) and alpha-terpineol (13.1%) were the major components identified in the rhizome oil.224305306Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Coupling of magnetization and structural distortions in multiferroic BiFeO3 : an ab initio density functional theory study

This paper has been withdrawn by the author due to a crucial citing error in equation 4.Comment: This paper has been withdra