Akhtarulrich1896

We calculate the plasmon frequency ω and damping rate γ of plasma oscillations in a spin-polarized BLG system. Using the long wavelength approximation for dynamical dielectric function, we obtain an analytical expression for plasmon frequency showing that degree of spin polarization P has negligible effect on the long wavelength plasmon frequency. Numerical calculations demonstrate that the plasmon frequency increases (decreases) noticeably (slightly) with the increase in spin polarization in large (small) wave-vector q region. We also find that the damping rate and the shape of γ as a function of q depend strongly on P. The increase in carrier density decreases significantly both plasmon frequency and damping rate independently of the spin polarization. The numerically calculated critical wave vector, at which the plasmon dispersion curve hits the edge of electron-hole continuum, decreases with P and can be used to experimentally determine the degree of spin polarization.

Dynamic latent state models are widely used to characterize the dynamics of brain network activity for various neural signal types. To date, dynamic latent state models have largely been developed for stationary brain network dynamics. However, brain network dynamics can be non-stationary for example due to learning, plasticity or recording instability. To enable modeling these non-stationarities, two problems need to be resolved. First, novel methods should be developed that can adaptively update the parameters of latent state models, which is difficult due to the state being latent. Second, new methods are needed to optimize the adaptation learning rate, which specifies how fast new neural observations update the model parameters and can significantly influence adaptation accuracy.

We develop a Rate Optimized-adaptive Linear State-Space Modeling (RO-adaptive LSSM) algorithm that solves these two problems. First, to enable adaptation, we derive a computation- and memory-efficient adaptive LSSM fitting albrain stimulation systems.

These algorithms can be used to study time-varying neural dynamics underlying various brain functions and enhance future neurotechnologies such as brain-machine interfaces and closed-loop brain stimulation systems.A novel scheme of silicon-assisted surface enhanced fluorescence (SEF) is presented for SEF-based assays, where the blank signal suppression and the fluorescence signal enhancement is combined. The P-doped, (100) oriented silicon substrate is used to quench the fluorescence of Rose Bengal (RB) molecules attached to it, resulting in an effectively suppressed background signal, which is useful for a lower limit of detection (LOD). When a proper quantity of silver nanoparticles (AgNPs) is deposited on the RB-attached silicon substrate, a significant fluorescence enhancement of up to around 290 fold is obtained, which helps to improve the sensitivity in fluorescence-based assays. Besides, conventional gold nanoparticles (AuNPs) have also been demonstrated to exhibit excellent SEF effect using the presented scheme, providing improved stability and biocompatibility. The mechanism of the observed SEF effect has been investigated, and both the decreased apparent quantum yield and the silicon-induced electric field redistribution are considered to play important roles. The experimental results suggest that the presented scheme holds great potential in the SEF-based assays aiming at higher sensitivity and lower LOD.Among the group-III chalcogenides, the two-dimensional (2D) GaSe and GaTe materials have been synthesized, but recent theoretical studies have raised controversial results regarding their thermoelectric (TE) properties. Hereby, systematically investigated the temperature and carrier concentration dependent TE properties of 2D GaSe and GaTe. We found that the GaSe had an indirect band gap of 2.94 eV while the GaTe had an indirect band gap of 1.88 eV. Selleckchem BMS-986020 Both materials had almost the same Seebeck coefficients, but the p-type GaTe had the longest carrier relaxation time. We obtained the largest electrical conductivity over the thermal conductivity ratio in p-type GaTe compared with all other systems. This results in a very high p-type ZT of 0.91. Moreover, this high ZT performance is only changed by approximately 7% in a wide range of temperatures (300-700 K) and carrier concentration (1011-1013 hole cm-2). Compared with previously reported results, we find that it is necessary to consider the carrier relaxation time and spin-orbit coupling effect for determining reliable TE property. Overall, we propose that the p-type GaTe have outstanding TE property, and it can be utilized for potential TE device applications.CVD graphene grown on metallic substrates presents, in several cases, a long-range periodic structure due to a lattice mismatch between the graphene and the substrate. For instance, graphene grown on Ir(111), displays a corrugated supercell with distinct adsorption sites due to a variation of its local electronic structure. This type of surface reconstruction represents a challenging problem for a detailed atomic surface structure determination for experimental and theoretical techniques. In this work, we revisited the surface structure determination of graphene on Ir(111) by using the unique advantage of surface and chemical selectivity of synchrotron-based photoelectron diffraction. We take advantage of the Ir 4f photoemission surface state and use its diffraction signal as a probe to investigate the atomic arrangement of the graphene topping layer. We determine the average height and the overall corrugation of the graphene layer, which are respectively equal to 3.40 ± 0.11 Å and 0.45 ± 0.03 Å. Furthermore, we explore the graphene topography in the vicinity of its high-symmetry adsorption sites and show that the experimental data can be described by three reduced systems simplifying the moiré supercell multiple scattering analysis.Ewing's sarcoma is the most aggressive connective tissue tumor, mainly affecting children and adolescents; the 5 year survival rate is only 50%. Current treatments have poor effectiveness, and more efficient treatments are being sought. Silver-based nanoparticles, such as silver chloride nanoparticles (AgCl-NPs) and silver/silver chloride (Ag/AgCl-NPs) nanoparticles, can be biologically produced and can release Ag+ ions into solution; however, their antitumor activity has been minimally investigated. The aim of this study was to evaluate the antitumor potential of AgCl-NPs and Ag/AgCl-NPs against Ewing's sarcoma cells. A673 cells (Ewing's sarcoma) were treated for 72 h with 0-12.5 μg ml-1 of Ag/AgCl-NPs or 0-40 μg ml-1 of AgCl-NPs. Human cells from the RPE-1 cell line (pigmented retinal epithelium) were used as a model of nontumor cells. The RPE-1 cells were less affected by the administration of AgCl-NPs or Ag/AgCl-NPs, with small reductions in the number of cells and viability and a small increase in apoptosis rates, while lysosomal damage, changes in reactive oxygen species (ROS) production, loss of mitochondrial membrane potential and alterations in microfilaments or cell areas were not observed.