5,107 research outputs found
Electrons surf phason waves in moiré bilayers
We investigate the effect of thermal fluctuations on the atomic and electronic structure of a twisted MoSe2/WSe2 heterobilayer using a combination of classical molecular dynamics and ab initio density functional theory calculations. Our calculations reveal that thermally excited phason modes give rise to an almost rigid motion of the moiré lattice. Electrons and holes in low-energy states are localized in specific stacking regions of the moiré unit cell and follow the thermal motion of these regions. In other words, charge carriers surf phason waves that are excited at finite temperatures. We also show that such surfing survives in the presence of a substrate and frozen potential. This effect has potential implications for the design of charge and exciton transport devices based on moiré materials
Effect of Sublethal Concentration of Malathion Insecticide on Innate Immune System, Immune Function and Hemocytes of Adult Drosophila melanogaster
Invertebrate organisms mostly have innate immune system. Hemocytes are the immune cells of the innate immunity in invertebrates. Our study was designed to observe the effect of malathion insecticide on the innate immune system, immune function and hemocytes of Drosophila melanogaster. A hemocytometer was used for total count of hemocytes which showed a reduced percentage of live cells (from 91.63% to 44.57%) due to the treatment. For differential count, the hemolymph was spread as a smear on a clean grease free slide. It was observed that the plasmatocyte count considerably decreased under the effect of malathion (from 78% to 44.66%). Lamellocytes also showed a decline in their number (from 18.33% to 12.61%). But, a trivial increase (from 3.67% to 3.98%) in crystal cell count was recorded. Our result suggests that malathion has mostly negative effect on hemocytes. This study could help in understanding of insect defense mechanism against such hazardous chemicals. Additionally, the function of human macrophages is analogous to the function of plasmatocytes. Hence, this work could possibly aid us in studying the response of human immune cells against organophosphates like malathion
Quantum chaos in the spectrum of operators used in Shor's algorithm
We provide compelling evidence for the presence of quantum chaos in the
unitary part of Shor's factoring algorithm. In particular we analyze the
spectrum of this part after proper desymmetrization and show that the
fluctuations of the eigenangles as well as the distribution of the eigenvector
components follow the CUE ensemble of random matrices, of relevance to
quantized chaotic systems that violate time-reversal symmetry. However, as the
algorithm tracks the evolution of a single state, it is possible to employ
other operators, in particular it is possible that the generic quantum chaos
found above becomes of a nongeneric kind such as is found in the quantum cat
maps, and in toy models of the quantum bakers map.Comment: Title and paper modified to include interesting additional
possibilities. Principal results unaffected. Accepted for publication in
Phys. Rev. E as Rapid Com
Towards equation of state of dark energy from quasar monitoring: reverberation strategy
Context. High-redshift quasars can be used to constrain the equation of state of dark energy. They can serve as a complementary tool to supernovae Type Ia, especially at z > 1
Chiral valley phonons and flat phonon bands in moire materials
We investigate the chirality of phonon modes in twisted bilayer WSe 2 and demonstrate distinct chiral behavior of the K / K ′ valley phonons for twist angles close to 0 ∘ and close to 60 ∘ . In particular, multiple chiral nondegenerate K / K ′ valley phonons are found for twist angles near 60 ∘ whereas no nondegenerate chiral modes are found for twist angles close to 0 ∘ . Moreover, we discover two sets of emergent chiral valley modes that originate from an inversion symmetry breaking at the moiré scale and find similar modes in moiré patterns of strain-engineered bilayers WSe 2 and MoSe 2 / WSe 2 heterostructures. At the energy gap between acoustic and optical modes, the formation of flat phonon bands for a broad range of twist angles is observed in twisted bilayer WSe 2 . Our findings are relevant for understanding electron-phonon and exciton-phonon scattering in moiré materials and also for the design of phononic analogues of flat band electrons
Laser surface nitriding of Ti-6Al-4V for bio-implant application
The present study aims at enhancing the biocompatibility of Ti-6Al-4V by laser surface nitriding. Laser surface nitriding has been carried out by melting of sand blasted Ti-6Al-4V substrate using a high power continuous wave DIODE laser with nitrogen as shrouding environment (at a pressure of 5l/min). Following laser treatment, a detailed characterization of the surface has been conducted. Microhardness and biocompatibility have been evaluated. Laser surface nitriding led to formation of dendrites of TiN on the surface. The microhardness is improved to 900- 950 VHN (in laser surface nitriding) as compared to 260 VHN of as-received substrate. Biocompatibility behavior showed a better cell viability in laser surface nitrided Ti-6Al-4V sample as compared to as-received one
Fragmentation and dynamics of dense gas structures in the proximity of massive young stellar object W42-MME
We present an analysis of the dense gas structures in the immediate
surroundings of the massive young stellar object (MYSO) W42-MME, using the
high-resolution (0.310.25) ALMA dust continuum and molecular
line data. We performed a dendrogram analysis of HCO (4-3) line
data to study multi-scale structures and their spatio-kinematic properties, and
analyzed the fragmentation and dynamics of dense structures down to 2000
AU scale. Our results reveal 19 dense gas structures, out of which 12 are
leaves and 7 are branches in dendrogram terminology. These structures exhibit
transonic-supersonic gas motions (1) with overvirial states
(). The non-thermal velocity dispersion-size relation
() of dendrogram structures shows a weak negative
correlation, while the velocity dispersion across the sky
() correlates positively with structure size ().
Velocity structure function () analysis of HCO
data reveals strong power-law dependencies with lag () up to a scale length
of 6000 AU. The mass-size () relation of dendrogram structures
shows a positive correlation with power-law index of 1.730.23, and the
leaf L17 hosting W42-MME meets the mass-size conditions for massive star
formation. Blue asymmetry is observed in the HCO (4-3) line
profiles of most of the leaves, indicating infall. Overall, our results
observationally support the hierarchical and chaotic collapse scenario in the
proximity of the MYSO W42-MME.Comment: 16 pages, 13 figures, 1 Table, Accepted for publication in Monthly
Notices of the Royal Astronomical Society (MNRAS) Journa
Analysis of Transcripts Expressed in One-Day-Old Larvae and Fifth Instar Silk Glands of Tasar Silkworm, Antheraea mylitta
Antheraea mylitta is one of the wild nonmulberry silkworms, which produces tasar silk. An EST project has been undertaken to understand the gene expression profile of A. mylitta silk gland. Two cDNA libraries, one from the whole bodies of one-day-old larvae and the other from the silkglands of fifth instar larvae, were constructed and sequenced. A total of 2476 good-quality ESTs (1239 clones) were obtained and grouped into 648 clusters containing 390 contigs and 258 singletons to represent 467 potential unigenes. Forty-five sequences contained putative coding region, and represented potentially novel genes. Among the 648 clusters, 241 were categorized according to Gene Ontology hierarchy and showed presence of several silk and immune-related genes. The A. mylitta ESTs have been organized into a freely available online database “AmyBASE”. These data provide an initial insight into the A. mylitta transcriptome and help to understand the molecular mechanism of silk protein production in a Lepidopteran species
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