1,311 research outputs found
Chiral Electronics
We consider the properties of electric circuits involving Weyl semimetals.
The existence of the anomaly-induced chiral magnetic current in a Weyl
semimetal subjected to magnetic field causes an interesting and unusual
behavior of such circuits. We consider two explicit examples: i) a circuit
involving the "chiral battery" and ii) a circuit that can be used as a "quantum
amplifier" of magnetic field. The unique properties of these circuits stem from
the chiral anomaly and may be utilized for creating "chiral electronic"
devices.Comment: 5 pages, 2 figures; final version to appear in Physical Review
1/2 BPS Geometries of M2 Giant Gravitons
We construct the general 1/2 BPS M2 giant graviton solutions asymptotic to
the eleven-dimensional maximally supersymmetric plane wave background, based on
the recent work of Lin, Lunin and Maldacena. The solutions have null
singularity and we argue that it is unavoidable to have null singularity in the
proposed framework, although the solutions are still physically relevant. They
involve an arbitrary function F(x) which is shown to have a correspondence to
the 1/2 BPS states of the BMN matrix model. A detailed map between the 1/2 BPS
states of both sides is worked out.Comment: 21 pages and 1 figure. v2: references added, comments adde
Influence of the anion potential on the charge ordering in quasi-one dimensional charge transfer salts
We examine the various instabilities of quarter-filled strongly correlated
electronic chains in the presence of a coupling to the underlying lattice. To
mimic the physics of the (TMTTF)X Bechgaard-Fabre salts we also include
electrostatic effects of intercalated anions. We show that small displacements
of the anion can stabilize new mixed Charged Density Wave-Bond Order Wave
phases in which central symmetry centers are suppressed. This finding is
discussed in the context of recent experiments. We suggest that the recently
observed charge ordering is due to a cooperative effect between the Coulomb
interaction and the coupling of the electronic stacks to the anions. On the
other hand, the Spin-Peierls instability at lower temperature requires a
Peierls-like lattice coupling.Comment: Latex, 4 pages, 4 postscript figure
Effect of incorporating different polyaniline-surface modified nanosilica content into polyurethane-based quasi-solid-state electrolyte for dye-sensitized solar cells
Polyanilineâsurface modified nanosilica (SâPANi) was incorporated into polyurethane (PU) to form a polymer matrix able to entrap liquid electrolyte and to function as a quasiâsolid state electrolyte (QSE) in dyeâsensitized solar cells (DSSCs). Nanosilica was first synthesized via solâgel technique and was post modified with aniline to form SâPANi. The effects of introducing different SâPANi content (5, 10, 15, and 20 wt%) on the nanoparticle distribution, surface morphology, surface porosity, thermal stability, and the structure of the PU matrix were analyzed using transmitted and reflected light microscopes, TGA and Xâray powder diffraction. Additionally, polymer matrix absorptivity, conductivity, and ion diffusion of the formulated QSEs were investigated by using a digital analytical balance, the AC impedance method, and cyclic voltammetry. Lastly, all of the formulated quasiâsolidâstate electrolytes were applied for use in DSSCs wherein their charge recombination, photovoltaic performance, and lifespan were measured. The quasiâsolidâstate electrolyte based on 15 wt% SâPANi (PUâ15%SâPANi) exhibited the highest lightâtoâenergy conversion efficiency, namely 3.17%, with an open circuit voltage of 708 mV, a short circuit current of 4.13 mA cmâ»ÂČ, and a fill factor of 0.65
Neuroprotective Effects against Glutamate-Induced HT-22 Hippocampal Cell Damage and Caenorhabditis elegans Lifespan/Healthspan Enhancing Activity of Auricularia polytricha Mushroom Extracts.
Oxidative stress is associated with several diseases, particularly neurodegenerative diseases, commonly found in the elderly. The attenuation of oxidative status is one of the alternatives for neuroprotection and anti-aging. Auricularia polytricha (AP), an edible mushroom, contains many therapeutic properties, including antioxidant properties. Herein, we report the effects of AP extracts on antioxidant, neuroprotective, and anti-aging activities. The neuroprotective effect of AP extracts against glutamate-induced HT-22 neuronal damage was determined by evaluating the cytotoxicity, intracellular reactive oxygen species (ROS) accumulation, and expression of antioxidant enzyme genes. Lifespan and healthspan assays were performed to examine the effects of AP extracts from Caenorhabditis elegans. We found that ethanolic extract (APE) attenuated glutamate-induced HT-22 cytotoxicity and increased the expression of antioxidant enzyme genes. Moreover, APE promoted in the longevity and health of the C. elegans. Chemical analysis of the extracts revealed that APE contains the highest quantity of flavonoids and a reasonable percentage of phenols. The lipophilic compounds in APE were identified by gas chromatography/mass spectrometry (GC/MS), revealing that APE mainly contains linoleic acid. Interestingly, linoleic acid suppressed neuronal toxicity and ROS accumulation from glutamate induction. These results indicate that AP could be an exciting natural source that may potentially serves as neuroprotective and anti-aging agents
Enhanced Transmission of Light and Particle Waves through Subwavelength Nanoapertures by Far-Field Interference
Subwavelength aperture arrays in thin metal films can enable enhanced
transmission of light and matter (atom) waves. The phenomenon relies on
resonant excitation and interference of the plasmon or matter waves on the
metal surface. We show a new mechanism that could provide a great resonant and
nonresonant transmission enhancement of the light or de Broglie particle waves
passed through the apertures not by the surface waves, but by the constructive
interference of diffracted waves (beams generated by the apertures) at the
detector placed in the far-field zone. In contrast to other models, the
mechanism depends neither on the nature (light or matter) of the beams
(continuous waves or pulses) nor on material and shape of the multiple-beam
source (arrays of 1-D and 2-D subwavelength apertures, fibers, dipoles or
atoms). The Wood anomalies in transmission spectra of gratings, a long standing
problem in optics, follow naturally from the interference properties of our
model. The new point is the prediction of the Wood anomaly in a classical
Young-type two-source system. The new mechanism could be interpreted as a
non-quantum analog of the superradiance emission of a subwavelength ensemble of
atoms (the light power and energy scales as the number of light-sources
squared, regardless of periodicity) predicted by the well-known Dicke quantum
model.Comment: Revised version of MS presented at the Nanoelectronic Devices for
Defense and Security (NANO-DDS) Conference, 18-21 June, 2007, Washington, US
Regulators Associated with Clinical Outcomes Revealed by Dna Methylation Data in Breast Cancer
The regulatory architecture of breast cancer is extraordinarily complex and gene misregulation can occur at many levels, with transcriptional malfunction being a major cause. This dysfunctional process typically involves additional regulatory modulators including DNA methylation. Thus, the interplay between transcription factor (TF) binding and DNA methylation are two components of a cancer regulatory interactome presumed to display correlated signals. As proof of concept, we performed a systematic motif-based in silico analysis to infer all potential TFs that are involved in breast cancer prognosis through an association with DNA methylation changes. Using breast cancer DNA methylation and clinical data derived from The Cancer Genome Atlas (TCGA), we carried out a systematic inference of TFs whose misregulation underlie different clinical subtypes of breast cancer. Our analysis identified TFs known to be associated with clinical outcomes of p53 and ER (estrogen receptor) subtypes of breast cancer, while also predicting new TFs that may also be involved. Furthermore, our results suggest that misregulation in breast cancer can be caused by the binding of alternative factors to the binding sites of TFs whose activity has been ablated. Overall, this study provides a comprehensive analysis that links DNA methylation to TF binding to patient prognosis
Mushroom-derived bioactive compounds potentially serve as the inhibitors of SARS-CoV-2 main protease: An in silico approach
Background and aim
Coronavirus Disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has now become the world pandemic. There is a race to develop suitable drugs and vaccines for the disease. The anti-HIV protease drugs are currently repurposed for the potential treatment of COVID-19. The drugs were primarily screened against the SARS-CoV-2 main protease. With an urgent need for safe and effective drugs to treat the virus, we have explored natural products isolated from edible and medicinal mushrooms that have been reported to possess anti-HIV protease.
Experimental procedures
We have examined 36 compounds for their potential to be SARS-CoV-2 main protease inhibitors using molecular docking study. Moreover, drug-likeness properties including absorption, distribution, metabolism, excretion and toxicity were evaluated by in silico ADMET analysis.
Results
Our AutoDock study showed that 25 of 36 candidate compounds have the potential to inhibit the main viral protease based on their binding affinity against the enzymeâs active site when compared to the standard drugs. Interestingly, ADMET analysis and toxicity prediction revealed that 6 out of 25 compounds are the best drug-like property candidates, including colossolactone VIII, colossolactone E, colossolactone G, ergosterol, heliantriol F and velutin.
Conclusion
Our study highlights the potential of existing mushroom-derived natural compounds for further investigation and possibly can be used to fight against SARS-CoV-2 infection.
Taxonomy (classification by evise)
Disease, Infectious Disease, Respiratory System Disease, Covid-19, Traditional Medicine, Traditional Herbal Medicine, Phamaceutical Analysis
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