Anomalous Hall conductivity control in Mn3_3NiN antiperovskite by epitaxial strain along the kagome plane

Antiferromagnetic manganese-based nitride antiperovskites, such as Mn$_3$NiN, hold a triangular frustrated magnetic ordering over their kagome lattice formed by the Mn atoms along the (111)-plane. As such, frustration imposes a non-trivial interplay between the symmetric and asymmetric magnetic interactions, which can only reach equilibrium in a noncollinear magnetic configuration. Consequently, the associated electronic interactions and their possible tuning by external constraints, such as applied epitaxial strain, play a crucial role in defining the microscopic and macroscopic properties of such topological condensed matter systems. Thus, in the present work, we explored and explained the effect of the epitaxial strain imposed within the (111)-plane, in which the magnetic and crystallographic symmetry operations are kept fixed, and only the magnitude of the ionic and electronic interactions are tuned. We found a linear shifting in the energy of the band structure and a linear increase/decrease of the available states near the Fermi level with the applied strain. Concretely, the compression strain reduces the Mn-Mn distances in the (111) kagome plane but linearly increases the separation between the stacked kagome lattices and the available states near the Fermi level. Despite the linear controlling of the available states across the Fermi energy, the anomalous Hall conductivity shows a non-linear behavior where the $\sigma_{111}$ conductivity nearly vanishes for tensile strain. On the other hand, $\sigma_{111}$ fetches a maximum increase of 26\% about the unstrained structure for a compression value close to $-$1.5\%.This behavior found an explanation in the non-divergent Berry curvature within the kagome plane, which is increased for constraining but significantly reduced for expansion strain values..

Increased mRNA expression of cytochrome oxidase in dorsal raphe nucleus of depressive suicide victims

Suicidal behavior is a problem with important social repercussions. Some groups of the population show a higher risk of suicide; for example, depression, alcoholism, psychosis or drug abuse frequently precedes suicidal behavior. However, the relationship between metabolic alterations in the brain and premorbid clinical symptoms of suicide remains uncertain. The serotonergic and noradrenergic systems have frequently been, implicated in suicidal behavior and the amount of serotonin in the brain and CSF of suicide victims has been found to be low compared with normal subjects. However, there are contradictory results regarding the role of noradrenergic neurons in the mediation of suicide attempts, possibly reflecting the heterogeneity of conditions that lead to a common outcome. In the present work we focus on the subgroup of suicide victims that share a common diagnosis of major depression. Based on post-mortem studies analyzing mRNA expression by in situ hybridization, serotonergic neurons from the dorsal raphe nucleus (DRN) from depressive suicide victims are seen to over-express cytochrome oxidase mRNA. However, no corresponding changes were found in the expression of tyrosine hydroxylase (TH) mRNA in the noradrenergic neurons of the Locus Coeruleus (LC). These results suggest that, despite of the low levels of serotonin described in suicide victims, the activity of DRN neurons could increase in the suicidally depressed, probably due to the over activation of serotonin re-uptake. No alteration was found in noradrenergic neurons, suggesting that they play no crucial role in the suicidal behavior of depressive patients

Isolation,selection and molecular identification of biosurfactant-producing extremophilicbacteries from crude oil polluted soil

© 2016,International Journal of Pharmacy and Technology. All rights reserved.Ten bacterial strains with hydrocarbon degrading capacity were isolated from a soil sample that had been polluted with crude oil from the area of Surgut in Russian Federation. This area is characterized by its long winters,with an annual average temperature of-1.7ºC. The isolated bacterial strains live and thrive at a very low temperature,which makes them ideal to be used in unfavorable environmental conditions for the majority of surfactants.In order to evaluate the biosurfactant production of these strains,the following methods were used: surface tension measurements,drop dispersion,hemolytic capacities assay and emulsification rate assay.These analysis showed that two of the strains,Bacillus subtilis and Klebsiellaoxytoca,was efficient biosurfactant producers. The surface tension decrease when using B.subtilisand K. oxytoca was 64.3% and 57.1% respectively. Drop dispersion was 33mm with B.subtilis and 28mm with K.oxytoca. The emulsification rate when using B.subtilis and K.oxytoca was 78.4% and 59.2% respectively. Our research has prospects to be applied both for microbial enhanced oil recovery (MEOR) and for bioremediation

Surgical repair of truncal valve regurgitation†

OBJECTIVES Truncal valve regurgitation remains a short- and long-term risk factor for patients with truncus arteriosus. There are limited data available on techniques and outcomes of truncal valve repair (TVR). The aim of this study was to report our experience with TVR in patients of all ages. METHODS From 1997 to 2012, 36 patients (13 neonates, 30 children and 3 adults) underwent TVR for significant regurgitation. RESULTS There were 3 early deaths (8%), all of which were in neonates. Twenty-two patients had a quadricuspid, 13 a tricuspid and 1 a bicuspid truncal valve before repair. Valve repair improved regurgitation in 31 of 36 repairs. The median regurgitation decreased from moderate-severe to mild (P < 0.001). During a mean follow-up of 38.3 ± 44.9 months (range 1 month—15 years), there was 1 late death, 16 patients required reoperation on the truncal valve and 1 required a second reoperation. Freedom from reoperation was 91.4 ± 4.8% at 1 year, 55.0 ± 10.4% at 5 and 22.9 ± 12.2% at 10 years. A quadricuspid valve after repair tended to worsen freedom from reoperation (P = 0.15), and tricuspidization tended to improve freedom from reoperation (P = 0.19). Neonatal repair (hazards ratio (HR) 4.1, P = 0.03) and leaflet thinning (HR 22.5, P = 0.002) were independent predictors of reoperation. CONCLUSIONS Valve repair for truncal valve regurgitation is feasible, with good results. Surgical creation of a tricuspid truncal valve seems to provide the best outcomes in this challenging populatio

A Mathematical Model to Optimize the Neoadjuvant Chemotherapy Treatment Sequence for Triple-Negative Locally Advanced Breast Cancer

Background: Triple-negative locally advanced breast cancer is an aggressive tumor type. Currently, the standard sequence treatment is applied, administering anthracyclines first and then a taxane plus platinum. Clinical studies for all possible treatment combinations are not practical or affordable, but mathematical modeling of the active mitotic cell population is possible. Our study aims to show the regions with the tumor’s most substantial cellular population variation by utilizing all possible values of the parameters () that define the annihilatory drug capacity according to the proposed treatment. Method: A piecewise linear mathematical model was used to analyze the cell population growth by applying four treatments: standard sequences of 21 days (SS21) and 14 days (SS14), administering anthracyclines first, followed by a taxane plus platinum, and inverted sequences of 21 days (IS21) and 14 days (IS14), administering a taxane plus platinum first then anthracyclines. Results: The simulation showed a higher effect of IS14 over SS14 when the rate of drug resistance was larger in the cell population during DNA synthesis (G1 and S) compared to cells in mitosis (G2 and M). However, if the proportion of resistant cells in both populations was equivalent, then treatments did not differ. Conclusions: When resistance is considerable, IS14 is more efficient than SS14, reducing the tumor population to a minimum

Daily monitoring of TeV gamma-ray emission from Mrk 421, Mrk 501, and the Crab Nebula with HAWC

We present results from daily monitoring of gamma rays in the energy range $\sim0.5$ to $\sim100$ TeV with the first 17 months of data from the High Altitude Water Cherenkov (HAWC) Observatory. Its wide field of view of 2 steradians and duty cycle of $>95$% are unique features compared to other TeV observatories that allow us to observe every source that transits over HAWC for up to $\sim6$ hours each sidereal day. This regular sampling yields unprecedented light curves from unbiased measurements that are independent of seasons or weather conditions. For the Crab Nebula as a reference source we find no variability in the TeV band. Our main focus is the study of the TeV blazars Markarian (Mrk) 421 and Mrk 501. A spectral fit for Mrk 421 yields a power law index $\Gamma=2.21 \pm0.14_{\mathrm{stat}}\pm0.20_{\mathrm{sys}}$ and an exponential cut-off $E_0=5.4 \pm 1.1_{\mathrm{stat}}\pm 1.0_{\mathrm{sys}}$ TeV. For Mrk 501, we find an index $\Gamma=1.60\pm 0.30_{\mathrm{stat}} \pm 0.20_{\mathrm{sys}}$ and exponential cut-off $E_0=5.7\pm 1.6_{\mathrm{stat}} \pm 1.0_{\mathrm{sys}}$ TeV. The light curves for both sources show clear variability and a Bayesian analysis is applied to identify changes between flux states. The highest per-transit fluxes observed from Mrk 421 exceed the Crab Nebula flux by a factor of approximately five. For Mrk 501, several transits show fluxes in excess of three times the Crab Nebula flux. In a comparison to lower energy gamma-ray and X-ray monitoring data with comparable sampling we cannot identify clear counterparts for the most significant flaring features observed by HAWC.Comment: 18 pages, 10 figures, accepted for publication in The Astrophysical Journa

The 2HWC HAWC Observatory Gamma Ray Catalog

We present the first catalog of TeV gamma-ray sources realized with the recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the most sensitive wide field-of-view TeV telescope currently in operation, with a 1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an instantaneous field of view >1.5 sr and >90% duty cycle, it continuously surveys and monitors the sky for gamma ray energies between hundreds GeV and tens of TeV. HAWC is located in Mexico at a latitude of 19 degree North and was completed in March 2015. Here, we present the 2HWC catalog, which is the result of the first source search realized with the complete HAWC detector. Realized with 507 days of data and represents the most sensitive TeV survey to date for such a large fraction of the sky. A total of 39 sources were detected, with an expected contamination of 0.5 due to background fluctuation. Out of these sources, 16 are more than one degree away from any previously reported TeV source. The source list, including the position measurement, spectrum measurement, and uncertainties, is reported. Seven of the detected sources may be associated with pulsar wind nebulae, two with supernova remnants, two with blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa