Linear Response Calculations of Lattice Dynamics in Strongly Correlated Systems

We introduce a new linear response method to study the lattice dynamics of materials with strong correlations. It is based on a combination of dynamical mean field theory of strongly correlated electrons and the local density functional theory of electronic structure of solids. We apply the method to study the phonon dispersions of a prototype Mott insulator NiO. Our results show overall much better agreement with experiment than the corresponding local density predictions.Comment: 4 pages, 2 figure

In-vitro anticancer activity against Caco-2 cell line of colloidal nano silver synthesized using aqueous extract of Eucalyptus Camaldulensis leaves

In the current study, we investigated the anticancer potential against human colon cells (Caco-2) of colloidal nanosilver (CN–Ag) produced in Syria using bioactive compounds in the aqueous extract of Eucalyptus camaldulensis leaves (AEECL). The formation of AgNPs was confirmed by UV-visible spectroscopy analysis with surface plasmon peak at 449 nm and their average size was found to be 12, 10, 23 nm by SEM, DLS and NTA respectively. This small size has confirmed the effective role of AEECL as capping agent. Further morphological characterization was done by EDS showed the presence of metallic silver. Zeta potential value (-23 mV) indicated the repulsion among the particles and stability of the formulation nanosilver. The anticancer effect of synthesized CN–Ag against Caco-2 has been tested. The cytotoxicity assay showed a dose-dependent and a time-dependent effect of CN–Ag. The high cytotoxicity of CN–Ag at low concentration (5μ/mL) open new prospects for the development of novel therapeutic approaches against human colon cancer Caco-2

Ukuran Populasi Efektif, Ukuran Populasi Aktual dan Laju Inbreeding Per Generasi Itik Lokal di Kecamatan Tilatang Kamang Kabupaten Agam

This study aims to obtain the effective population size, actual population size and rate of inbreeding of Kamang local duck. In this study used a sample local duck raised from 30 farmers. This research conducted was survey method with purposive random sampling. The variables were calculated in the study, namely the number of adult male ducks (Nm), number of adult female ducks (Nf), number of young male and young female ducks, number of male and female ducklings, actual population size (Na), effective population size (Ne), and the rate of inbreeding per generation (ΔF). The research was conducted in the District Tilatang Kamang of Agam Regency began on December 23, 2011 until January 25, 2012. The study concluded that the local duck population in the District Tilatang Kamang was 4.131 head. The highest populations were in Nagari Koto Tangah had 1.626 head of ducks. The structure population of the Local duck in the District Tilatang Kamang was an adult male ducks (11.73%), adult female ducks (24.88%), young male ducks (12.44%), young female ducks (13.12%), drake (13.58%), and female ducks (13.58%). Effective population size (Ne) Kamang Local ducks was 1.310 head and the rate of inbreeding per generation is 0.04%

Electron-phonon relaxation and excited electron distribution in zinc oxide and anatase

We propose a first-principle method for evaluations of the time-dependent electron distribution function of excited electrons in the conduction band of semiconductors. The method takes into account the excitations of electrons by external source and the relaxation to the bottom of conduction band via electron-phonon coupling. The methods permits calculations of the non-equilibrium electron distribution function, the quasi-stationary distribution function with steady-in-time source of light, the time of setting of the quasi-stationary distribution and the time of energy loss via relaxation to the bottom of conduction band. The actual calculations have been performed for titanium dioxide in the anatase structure and zinc oxide in the wurtzite structure. We find that the quasi-stationary electron distribution function for ZnO is a fermi-like curve that rises linearly with increasing excitation energy whereas the analogous curve for anatase consists of a main peak and a shoulder. The calculations demonstrate that the relaxation of excited electrons and the setting of the quasi-stationary distribution occur within the time no more than 500 fsec for ZnO and 100 fsec for anatase. We also discuss the applicability of the effective phonon model with energy-independent electron-phonon transition probability. We find that the model only reproduces the trends in changing of the characteristic times whereas the precision of such calculations is not high. The rate of energy transfer to phonons at the quasi-stationary electron distribution also have been evaluated and the effect of this transfer on the photocatalyses has been discussed. We found that for ZnO this rate is about 5 times less than in anatase.Comment: 21 p., 9 figure

The collapsed tetragonal phase as a strongly covalent and fully nonmagnetic state: persistent magnetism with interlayer As-As bond formation in Rh-doped Ca0.8_{0.8}Sr0.2_{0.2}Fe2_2As2_2

A well-known feature of CaFe$_{2}$As$_{2}$-based superconductors is the pressure-induced collapsed tetragonal phase that is commonly ascribed to the formation of an interlayer As-As bond. Using detailed X-ray scattering and spectroscopy, we find that Rh-doped Ca$_{0.8}$Sr$_{0.2}$Fe$_{2}$As$_{2}$ does not undergo a first-order phase transition and that local Fe moments persist despite the formation of interlayer As-As bonds. Our density functional theory calculations reveal that the Fe-As bond geometry is critical for stabilizing magnetism and that the pressure-induced drop in the $c$ lattice parameter observed in pure CaFe$_{2}$As$_{2}$ is mostly due to a constriction within the FeAs planes. These phenomena are best understood using an often overlooked explanation for the equilibrium Fe-As bond geometry, which is set by a competition between covalent bonding and exchange splitting between strongly hybridized Fe $3d$ and As $4p$ states. In this framework, the collapsed tetragonal phase emerges when covalent bonding completely wins out over exchange splitting. Thus the collapsed tetragonal phase is properly understood as a strong, covalent phase that is fully nonmagnetic with the As-As bond forming as a byproduct.Comment: 6 pages, 2 figures, and 1 table. Supplemental materials are available by reques

Adverse drug events associated with vitamin K antagonists: factors of therapeutic imbalance

Nancy El-Helou, Amal Al-Hajje, Rola Ajrouche, Sanaa Awada, Samar Rachidi, Salam Zein, Pascale SalamehClinical and Epidemiological Research Laboratory, Faculty of Pharmacy, Lebanese University, Beirut, LebanonBackground: Adverse drug events (ADE) occur frequently during treatment with vitamin K antagonists (AVK) and contribute to increase hemorrhagic risks.Methods: A retrospective study was conducted over a period of 2 years. Patients treated with AVK and admitted to the emergency room of a tertiary care hospital in Beirut were included. The aim of the study was to identify ADE characterized by a high international normalized ratio (INR) and to determine the predictive factors responsible for these events. Statistical analysis was performed with the SPSS statistical package.Results: We included 148 patients. Sixty-seven patients (47.3%) with an INR above the therapeutic range were identified as cases. The control group consisted of 81 patients (54.7%) with an INR within the therapeutic range. Hemorrhagic complications were observed in 53.7% of cases versus 6.2% of controls (P < 0.0001). No significant difference was noticed between cases and controls regarding the indication and the dose of AVK. Patients aged over 75 years were more likely to present an INR above the therapeutic range (58.2%, P = 0.049). Recent infection was present in 40.3% of cases versus 6.2% of controls (P < 0.0001) and hypoalbuminemia in 37.3% of cases versus 6.1% of controls (P < 0.0001). Treatment with antibiotics, amiodarone, and anti-inflammatory drugs were also factors of imbalance (P < 0.0001).Conclusion: Many factors may be associated with ADE related to AVK. Monitoring of INR and its stabilization in the therapeutic range are important for preventing these events.Keywords: adverse drug events, vitamin K antagonists, bleeding risks, therapeutic imbalanc

Pengaruh Pertumbuhan Laba, Struktur Modal, Likuiditas Dan Komisaris Independen Terhadap Kualitas Laba Dengan Komisaris Independen Dimoderasi Oleh Kompetensi Komisaris Independen (Studi Pada Perusahaan Manufaktur Yang Terdaftar Pada Bursa Efek Indonesia Pe

This study aimed to examine whether (1) the effect of earnings growth earnings quality, (2) the effect of the capital structure of the profit on the quality of earnings (3) the effect of liquidity on the quality of earnings and (4) the influence of independent directors to be moderated by the competence of independent directors on the quality of earnings on companies listed in the Indonesia Stock Exchange. Population of this research are manufacturing companies listed in Indonesia Stock Exchange (BEI) in 2013 until 2014. The research proves that (1) earnings growth positive significant effect on the quality of earnings with a significant level of 0.025, (2) the capital structure of a significant negative effect on the quality of earnings with a significant level of 0.200, (3) liquidity significant positive effect on the quality of earnings with significant level of 0.100 and (4) an independent commissioners significant negative effect on the quality of earnings with competence moderated by an independent commissioner with a significant level of 0.00

Linear-response theory and lattice dynamics: a muffin-tin orbital approach

A detailed description of a method for calculating static linear-response functions in the problem of lattice dynamics is presented. The method is based on density functional theory and it uses linear muffin-tin orbitals as a basis for representing first-order corrections to the one-electron wave functions. As an application we calculate phonon dispersions in Si and NbC and find good agreement with experiments.Comment: 18 pages, Revtex, 2 ps figures, uuencoded, gzip'ed, tar'ed fil

Lattice instabilities of cubic NiTi from first principles

The phonon dispersion relation of NiTi in the simple cubic B2 structure is computed using first-principles density-functional perturbation theory with pseudopotentials and a plane-wave basis set. Lattice instabilities are observed to occur across nearly the entire Brillouin zone, excluding three interpenetrating tubes of stability along the (001) directions and small spheres of stability centered at R. The strongest instability is that of the doubly degenerate M5' mode. The atomic displacements of one of the eigenvectors of this mode generate a good approximation to the observed B19' ground-state structure.Comment: 11 pages, 3 figure