Ab initio prediction of magnetically dead layers in freestanding γ\gamma-Ce(111)

It is well known that the surface of nonmagnetic $\alpha$-Ce is magnetically ordered, i.e., $\gamma$-like. One then might conjecture, in agreement with previous theoretical predictions, that the $\gamma$-Ce may also exhibit at its surfaces even more strongly enhanced $\gamma$-like magnetic ordering. Nonetheless, our result shows that the (111)-surfaces of magnetic $\gamma$-Ce are neither spin nor orbitally polarized, i.e., $\alpha$-like. Therefore, we predict, in contrast to the nonmagnetic $\alpha$-phase which tends to produce magnetically ordered $\gamma$-like thin layers at its free surfaces, the magnetic $\gamma$-phase has a tendency to form $\alpha$-like dead layers. This study, which explains the suppressed (promoted) surface magnetic moments of $\gamma$-Ce ($\alpha$-Ce), shows that how nanoscale can reverse physical properties by going from bulk to the surface in isostructural $\alpha$- and $\gamma$-phases of cerium. We predict using our freestanding surface results that a typical unreactive and non-diffusive substrate can dramatically influence the magnetic surface of cerium thin films in contrast to most of the uncorrelated thin films and strongly correlated transition metals. Our result implies that magnetic surface moments of $\alpha$-Ce(111) can be suddenly disappeared by increasing lattice mismatch at the interface of a typical unreactive and non-diffusive substrate with cerium overlayers.Comment: 6 pages, 3 figures, 1 tabl

Density functional approach to study structural properties and Electric Field Gradients in rare earth materials

We investigated the effect of spin polarization on the structural properties and gradient of electric field (EFG) on Sn, In, and Cd impurity in RSn$_3$ (R=Sm, Eu, Gd) and RIn$_3$ (R=Tm, Yb, Lu) compounds. The calculations were performed self-consistently using the scalar-relativistic full potential linearized augmented plane wave method. The local density approximations (LDA) and generalized gradient approximation without spin polarization (GGA) and with spin polarization (GGA+SP) to density functional theory were applied. In addition to that we performed some calculations within open core treatment (GGA+open core). It is clearly seen that GGA+SP is successful in predicting the larger lattice parameter and the dramatic drop of EFG for R=(Eu, Yb) relative to other rare earth compounds. This is an indication that spin splitting generated by spin polarization without any modification, is capable of treating properly the highly correlated f electrons in these systems.Comment: 14 Pages, 3 Figures, 5 Table

RESILIENCE OF NETWORKED INFRASTRUCTURE WITH EVOLVING COMPONENT CONDITIONS: A PAVEMENT NETWORK APPLICATION

This thesis deals with quantifying the resilience of a network of pavements. Calculations were carried out by modeling network performance under a set of possible damage-meteorological scenarios with known probability of occurrence. Resilience evaluation was performed a priori while accounting for optimal preparedness decisions and additional response actions that can be taken under each of the scenarios. Unlike the common assumption that the pre-event condition of all system components is uniform, fixed, and pristine, component condition evolution was incorporated herein. For this purpose, the health of the individual system components immediately prior to hazard event impact, under all considered scenarios, was associated with a serviceability rating. This rating was projected to reflect both natural deterioration and any intermittent improvements due to maintenance. The scheme was demonstrated for a hypothetical case study involving Laguardia Airport. Results show that resilience can be impacted by the condition of the infrastructure elements, their natural deterioration processes, and prevailing maintenance plans. The findings imply that, in general, upper bound values are reported in ordinary resilience work, and that including evolving component conditions is of value

Electronic structure and electric-field gradients analysis in CeIn3CeIn_3

Electric field gradients (EFG's) were calculated for the $CeIn_3$ compound at both $^{115}In$ and $^{140}Ce$ sites. The calculations were performed within the density functional theory (DFT) using the augmented plane waves plus local orbital (APW+lo) method employing the so-called LDA+U scheme. The $CeIn_3$ compound were treated as nonmagnetic, ferromagnetic, and antiferromagnetic cases. Our result shows that the calculated EFG's are dominated at the $^{140}Ce$ site by the Ce-4f states. An approximately linear relation is intuited between the main component of the EFG's and total density of states (DOS) at Fermi level. The EFG's from our LDA+U calculations are in better agreement with experiment than previous EFG results, where appropriate correlations had not been taken into account among 4f-electrons. Our result indicates that correlations among 4f-electrons play an important role in this compound and must be taken into account

The Correlation of Serum Chloride Level and Hospital Mortality in Multiple Trauma Patients

Introduction: Electrolyte disorder is a prevalent complication in multiple trauma patients; nevertheless, the role of chloride has been rarely addressed in literature when evaluating serum electrolytes. Objective: The present study was conducted to determine the correlation between serum chloride changes and hospital mortality in multiple trauma patients. Method: The present cross-sectional study measured serum chloride levels in 100 multiple trauma patients upon their admission to the emergency department and 24 hours later. All these patients were followed up in terms of hospital mortality using their medical records. Exact logistic regression was used to measure the effects of independent variables on hospital mortality in the patients. Results: Hospital mortality was found to be 15 (15%), and the mean serum chloride level to be 106.37±4.53 mmol/l upon admission and 112.18±6.16 mmol/l 24 hours later. Although the univariate analysis suggested that serum chloride levels were independently associated with mortality 24 hours after admission (P=0.005), this correlation was insignificant in the multivariate analysis. Conclusion: The present study rejected the hypothesis suggesting the potential role of serum chloride levels in predicting hospital mortality in multiple trauma patients

Novel inhibitor discovery against aromatase through virtual screening and molecular dynamic simulation

Inhibition of aromatase (CYTP450) as a key enzyme in the estrogen biosynthesis could result in regression of estrogen-dependent tumors and even preventing the promotion of breast cancer. Although today potent steroid and non-steroid inhibitors of aromatase are available, isoflavanone derivatives as natural compounds with least side effects have been described as the candidate for a new generation of aromatase inhibitors. 2a as an isoflavanone derivative is the most potent inhibitor of aromatase, synthesized by Bonfield et al. (2012). In our computational study, the mentioned compound was used as the template for virtual screening. Between 286 selected compounds with 70 % of structural similarity to 2a, 150 of them showed lower docking energy in comparison with 2a. Compound 2a_1 with 11.2 kcal/mol had the lowest docking energy. Interaction of 2a_1 with aromatase was further investigated and compared with 2a and androstenedione (ASD) as a natural substrate of aromatase, through 20 ns of molecular dynamic simulation. Analysis of trajectories showed, while ASD interacts with aromatase through hydrogen bonds and 2a just interacts via hydrophobic forces, 2a_1 not only accommodates in the hydrophobic active site of aromatase in a suitable manner but it also makes a stable coordination with iron atom of aromatase heme group via OB

Tunable relativistic quasiparticle electronic and excitonic behavior of the FAPb(I1−xBrx)3alloy

We study the structural, electronic, and excitonic properties of mixed FAPb(I1−xBrx)30 ≤x≤ 1 alloys by first-principles density functional theory as well as quasiparticle GW and Bethe Salpeter equation (BSE) approaches with the inclusion of relativistic effects through spin orbit coupling. Our results show that the system volume decreases with increasing Br content. The quasiparticle band gaps vary from 1.47 eV for pure α-FAPbI3to 2.20 eV for Br-rich α-FAPbBr3and show stronger correlation with the structural changes. The optical property analysis reveals that the overall excitonic peaks are blue shifted with the Br fraction. Our results further reveal strong Br concentration dependence of the variation in the exciton binding energy (from 74 to 112 meV) and the carrier effective masses as well as the high frequency dielectric constants. These findings provide a way to tune the carrier transport properties of the material by doping, which could be utilized to improve the short circuit currents and power conversion efficiencies in multijunction solar cell devices