Helical edge states in silicene and germanene nanorings in perpendicular magnetic field

Due to nonzero intrinsic spin-orbit interaction in buckled honeycomb crystal structures, silicene and germanene exhibit interesting topological properties, and are therefore candidates for the realization of the quantum spin Hall effect. We employ the Kane-Mele model to investigate the electron states in hexagonal silicene and germanene nanorings having either zigzag or armchair edges in the presence of a perpendicular magnetic field. We present results for the energy spectra as function of magnetic field, the electron density of the spin-up and spin-down states in the ring plane, and the calculation of the probability current density. The quantum spin Hall phase is found at the edges between the nontrivial topological phase in silicene and germanene and vacuum. We demonstrate that the helical edge states in zigzag silicene and germanene nanorings can be qualitatively well understood by means of classical magnetic moments. However, this is not the case for comparable-sized armchair nanorings, where the eigenfunctions spread throughout the ring. Finally, we note that the energy spectra of silicene and germanene nanorings are similar and that the differences between the two are mainly related to the difference in magnitude of the spin-orbit coupling.Comment: 17 pages, 10 figure

Effects of Community Exercise Therapy on Metabolic, Brain, Physical, and Cognitive Function Following Stroke : A Randomized Controlled Pilot Trial

© The Author(s) 2014.Peer reviewedPostprintPostprin

Iron concentrations in atherosclerotic plaque and serum in patients with carotid atherosclerosis

The aim of this study was to investigate the iron concentrations in serum and carotid plaque in patients with different morphology of carotid atherosclerotic plaque and compared with other metal ions. Carotid endarterectomy due to the significant atherosclerotic stenosis was performed in 91 patients. Control group consisted of 27 patients, without carotid atherosclerosis. Atherosclerotic plaques were divided into four morphological groups, according to ultrasonic and intraoperative characteristics. Iron, copper and zinc concentration in plaque, carotid artery and serum were measured by spectrophotometry. Serum iron concentrations were higher in patients with hemorrhagic plaques in comparison to the control group (4.7 μmol/l ± 1.2 vs. 2.1 μmol/l ± 0.8, p < 0.05). Iron concentrations were higher in patients with hemorrhagic plaques in comparison to fibrolipid plaques (72.1 ± 14.3 μg/g vs. 39.3 ± 22.9 μg/g; p < 0.05). Negative significant correlation was found for zinc in serum and plaque iron concentration in patients (p < 0.05). We also demonstrated positive significant correlation for copper and iron in serum (p < 0.05). The data obtained in the current study are consistent with the hypothesis that high iron levels may contribute to atherosclerosis and its complications as factors in a multifactorial disease

Dietary nitrate does not modify blood pressure and cardiac output at rest and during exercise in older adults : a randomised cross over study

Dietary nitrate (〖NO〗_3^-) supplementation has been associated with improved vascular and metabolic health. We conducted a double-blind, cross-over, placebo-controlled RCT to investigate the effects of 7-day consumption of beetroot juice compared with placebo on 1) blood pressure (BP) measured in resting conditions and during exercise, 2) cardiac and peripheral vascular function and 3) biomarkers of inflammation, oxidative stress and endothelial integrity. Twenty non-smoking healthy participants aged 60-75y and BMI 20.0-29.9kg/m2 were recruited. Measurement were conducted before and after each 7-day intervention period. Consumption of 〖NO〗_3^- had no effect on resting systolic and diastolic BP. 〖NO〗_3^- consumption did not improve indexes of central and peripheral cardiac function responses during cardiopulmonary exercise testing. Dietary 〖NO〗_3^- supplementation did not modify biomarkers of inflammation, oxidative stress and endothelial integrity. This study do not support the short-term benefits of dietary 〖NO〗_3^- supplementation on physiological and biochemical markers of vascular health in older healthy adults. Trial Registration: ISRCTN1906495

Lie group weight multiplicities from conformal field theory

Dominant weight multiplicities of simple Lie groups are expressed in terms of the modular matrices of Wess-Zumino-Witten conformal field theories, and related objects. Symmetries of the modular matrices give rise to new relations among multiplicities. At least for some Lie groups, these new relations are strong enough to completely fix all multiplicities.Comment: 12 pages, Plain TeX, no figure

A model for innovation in higher education

An extensive research and awareness about the role of innovation at education exist, but insight is missing regarding an individual frame of innovation of how to empower an individual towards life-long innovation activities. There is no adequate model that provides a holistic approach to innovation in academic institutions.This paper explores multiple innovation issues culminating in the development of a model for innovation from an individual perspective.This paper argues that awareness and the dynamics of individual innovation is missing in academic environments. Academics’ engagements in innovation endeavours are scarce; there are visible symptoms of deeply embedded social, institutional, cultural and individual factors of innovation. This requires a holistic approach in innovation research.Awareness of an individual’s potential and his/her innovation development cycles, external and internal dynamics can contribute to multiple innovation sustainability. These are pillars of the ORED model (observation, revelation, exploration, design) and ever expanding cycles for innovation

International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci.

The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5-20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson's disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations

A Minimal Threshold of c-di-GMP Is Essential for Fruiting Body Formation and Sporulation in Myxococcus xanthus

Generally, the second messenger bis-(3’-5’)-cyclic dimeric GMP (c-di-GMP) regulates the switch between motile and sessile lifestyles in bacteria. Here, we show that c-di-GMP is an essential regulator of multicellular development in the social bacterium Myxococcus xanthus. In response to starvation, M. xanthus initiates a developmental program that culminates in formation of spore-filled fruiting bodies. We show that c-di-GMP accumulates at elevated levels during development and that this increase is essential for completion of development whereas excess c-di-GMP does not interfere with development. MXAN3735 (renamed DmxB) is identified as a diguanylate cyclase that only functions during development and is responsible for this increased c-di-GMP accumulation. DmxB synthesis is induced in response to starvation, thereby restricting DmxB activity to development. DmxB is essential for development and functions downstream of the Dif chemosensory system to stimulate exopolysaccharide accumulation by inducing transcription of a subset of the genes encoding proteins involved in exopolysaccharide synthesis. The developmental defects in the dmxB mutant are non-cell autonomous and rescued by co-development with a strain proficient in exopolysaccharide synthesis, suggesting reduced exopolysaccharide accumulation as the causative defect in this mutant. The NtrC-like transcriptional regulator EpsI/Nla24, which is required for exopolysaccharide accumulation, is identified as a c-diGMP receptor, and thus a putative target for DmxB generated c-di-GMP. Because DmxB can be—at least partially—functionally replaced by a heterologous diguanylate cyclase, these results altogether suggest a model in which a minimum threshold level of c-di-GMP is essential for the successful completion of multicellular development in M. xanthus