205 research outputs found
Merging brain computing interface (BCI) & neural networks for better authentication & recognition
Merging brain computing interface (BCI) & neural networks for better authentication & recognition
Hybrid density functional study of electronic and optical properties of phase change memory material:
In this article, we use hybrid density functional (HSE06) to study the
crystal and electronic structures and optical properties of well known phase
change memory material . We calculate the
structural parameters, band gaps and dielectric functions of three stable
structures of this material. We also analyze the electron charge distribution
using the Bader's theory of charge analysis. We find that hybrid density
functional slightly overestimate the value of 'C' parameter. However, overall,
our results calculated with the use of hybrid density functional (HSE06) are
very close to available experimental values than calculated with the use of PBE
functional. Specifically, the electronic band gap values of this material
calculated with HSE06 are in good agreement with the available experimental
data in the literature. Furthermore, we perform the charge analysis and find
that naive ionic model fails to explain the charge distribution between the
constituent atoms, showing the complex nature of this compound.Comment: 10 pages, 3 tables, 3 figure
Biospectroscopy of Nanodiamond-Induced Alterations in Conformation of Intra- and Extracellular Proteins: A Nanoscale IR Study
The toxicity of nanomaterials raises major concerns because of the impact that nanomaterials may have on health,
which remains poorly understood. We need to explore the fate of individual nanoparticles in cells at nano and molecular levels to
establish their safety. Conformational changes in secondary protein structures are one of the main indicators of impaired biological
function and hence, the ability to identify these changes at a nanoscale level offers unique insights into the nanotoxicity of materials.
Here, we used nanoscale infrared spectroscopy and demonstrated for the first time that nanodiamonds induced alterations in
both extra- and intracellular secondary protein structures, leading to the formation of antiparallel β-sheet, β-turns, intermolecular β-
sheet and aggregation of proteins. These conformational changes of the protein structure may result in the loss of functionality of
proteins and in turn lead to adverse effects
Dynamics of multipartite quantum correlations under decoherence
Quantum discord is an optimal resource for the quantification of classical
and non-classical correlations as compared to other related measures. Geometric
measure of quantum discord is another measure of quantum correlations.
Recently, the geometric quantum discord for multipartite states has been
introduced by Jianwei Xu [arxiv:quant/ph.1205.0330]. Motivated from the recent
study [Ann. Phys. 327 (2012) 851] for the bipartite systems, I have
investigated global quantum discord (QD) and geometric quantum discord (GQD)
under the influence of external environments for different multipartite states.
Werner-GHZ type three-qubit and six-qubit states are considered in inertial and
non-inertial settings. The dynamics of QD and GQD is investigated under
amplitude damping, phase damping, depolarizing and flipping channels. It is
seen that the quantum discord vanishes for p>0.75 in case of three-qubit GHZ
states and for p>0.5 for six qubit GHZ states. This implies that multipartite
states are more fragile to decoherence for higher values of N. Surprisingly, a
rapid sudden death of discord occurs in case of phase flip channel. However,
for bit flip channel, no sudden death happens for the six-qubit states. On the
other hand, depolarizing channel heavily influences the QD and GQD as compared
to the amplitude damping channel. It means that the depolarizing channel has
the most destructive influence on the discords for multipartite states. From
the perspective of accelerated observers, it is seen that effect of environment
on QD and GQD is much stronger than that of the acceleration of non-inertial
frames. The degradation of QD and GQD happens due to Unruh effect. Furthermore,
QD exhibits more robustness than GQD when the multipartite systems are exposed
to environment.Comment: 15 pages, 4 figures, 4 table
Study and simulation of the energy performances of a grid-connected PV system supplying a residential house in north of Algeria
Decoherence and entanglement degradation of a qubit-qutrit system in non-inertial frames
We study the effect of decoherence on a qubit-qutrit system under the
influence of global, local and multilocal decoherence in non-inertial frames.
We show that the entanglement sudden death can be avoided in non-inertial
frames in the presence of amplitude damping, depolarizing and phase damping
channels. However, degradation of entanglement is seen due to Unruh effect. It
is shown that for lower level of decoherence, the depolarizing channel degrades
the entanglement more heavily as compared to the amplitude damping and phase
damping channels. However, for higher values of decoherence parameters,
amplitude damping channel heavily degrades the entanglement of the hybrid
system. Further more, no ESD is seen for any value of Rob's acceleration.Comment: 16 pages, 5 .eps figures, 1 table; Quantum Information Processing,
published online, 5 July, 201
An overview of enhancing drought tolerance in cotton through manipulating stress resistance genes
Drought stress affects the normal growth of plant by influencing Physiological, morphological molecular and biochemical traits at cellular level. It is a polygenic trait, controlled by multiple genes, which makes its manipulation difficult by genetic engineering. It seems drought could be major threat in future to high yield of cotton in Pakistan as well around the globe because it is spontaneous and cannot be controlled with manuring and skilled agricultural practices. Gene manipulation could be a solution of this threat by producing transgenic cotton plants. As it is polygenic trait, so, understanding about cellular mechanism of drought tolerance is crucial to impart tolerance by controlling gene expression under stressed conditions. Universal Stress Proteins (USP) genes have already been identified in drought stressed leaves of Gossypium arboreum which make this variety of cotton a rich source of stress tolerance genes. USP genes could be manipulated for drought tolerant transgenic cotton with high yielding as well and it is most important family of proteins in this regard. This family encompasses a conserved group of proteins that has been reported in different organisms which are activating under various abiotic stress conditions. USP is also a regulatory protein; its activity can be increased by manipulating its interactions
Biological impact of nanodiamond particles – label free, high-resolution methods for nanotoxicity assessment
Current methods for the assessment of nanoparticle safety that are based on 2D cell culture models and fluorescence-based assays show limited sensitivity and they lack biomimicry. Consequently, the health risks associated with the use of many nanoparticles have not yet been established. There is a need to develop in vitro models that mimic physiology more accurately and enable high throughput assessment. There is also a need to set up new assays that offer high sensitivity and are label-free. Here we developed ‘mini-liver’ models using scaffold-free bioprinting and used these models together with label-free nanoscale techniques for the assessment of toxicity of nanodiamond produced by laser-assisted technology. Results showed that NDs induced cytotoxicity in a concentration and exposure-time dependent manner. The loss of cell function was confirmed by increased cell stiffness, decreased cell membrane barrier integrity and reduced cells mobility. We further showed that NDs elevated the production of reactive oxygen species and reduced cell viability. Our approach that combined mini-liver models with label-free high-resolution techniques showed improved sensitivity in toxicity assessment. Notably, this approach allowed for label-free semi-high throughput measurements of nanoparticle-cell interactions, thus could be considered as a complementary approach to currently used methods
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