5,195 research outputs found
Theoretical prediction of topological insulator in ternary rare earth chalcogenides
A new class of three-dimensional topological insulator, ternary rare earth
chalcogenides, is theoretically investigated with ab initio calculations. Based
on both bulk band structure analysis and the direct calculation of topological
surface states, we demonstrate that LaBiTe3 is a topological insulator. La can
be substituted by other rare earth elements, which provide candidates for novel
topological states such as quantum anomalous Hall insulator, axionic insulator
and topological Kondo insulator. Moreover, YBiTe3 and YSbTe3 are found to be
normal insulators. They can be used as protecting barrier materials for both
LaBiTe3 and Bi2Te3 families of topological insulators for their well matched
lattice constants and chemical composition.Comment: 5 pages, 3 figures and 1 tabl
Quantum phase transition of condensed bosons in optical lattices
In this paper we study the superfluid-Mott-insulator phase transition of
ultracold dilute gas of bosonic atoms in an optical lattice by means of Green
function method and Bogliubov transformation as well. The superfluid-
Mott-insulator phase transition condition is determined by the energy-band
structure with an obvious interpretation of the transition mechanism. Moreover
the superfluid phase is explained explicitly from the energy spectrum derived
in terms of Bogliubov approach.Comment: 13 pages, 1 figure
Technique of quantum state transfer for a double Lambda atomic beam
The transfer technique of quantum states from light to collective atomic
excitations in a double type system is extended to matter waves in
this paper, as a novel scheme towards making a continuous atom laser. The
intensity of the output matter waves is found to be determined by the initial
relative phase of the two independent coherent probe lights, which may indicate
an interesting method for the measurement of initial relative phase of two
independent light sources.Comment: 5 pages, 2 figure
Control of Josephson current by Aharonov-Casher Phase in a Rashba Ring
We study the interference effect induced by the Aharonov-Casher phase on the
Josephson current through a semiconducting ring attached to superconducting
leads. Using a 1D model that incorporates spin-orbit coupling in the
semiconducting ring, we calculate the Andreev levels analytically and
numerically, and predict oscillations of the Josephson current due to the AC
phase. This result is valid from the point contact limit to the long channel
length limit, as defined by the ratio of the junction length and the BCS
healing length. We show in the long channel length limit that the impurity
scattering has no effect on the oscillation of the Josephson current, in
contrast to the case of conductivity oscillations in a spin-orbit coupled ring
system attached to normal leads where impurity scattering reduces the amplitude
of oscillations. Our results suggest a new scheme to measure the AC phase with,
in principle, higher sensitivity. In addition, this effect allows for control
of the Josephson current through the gate voltage tuned AC phase.Comment: 12pages, 8 figure
Possible steps of complete disassembly of post-termination complex by yeast eEF3 deduced from inhibition by translocation inhibitors.
Ribosomes, after one round of translation, must be recycled so that the next round of translation can occur. Complete disassembly of post-termination ribosomal complex (PoTC) in yeast for the recycling consists of three reactions: release of tRNA, release of mRNA and splitting of ribosomes, catalyzed by eukaryotic elongation factor 3 (eEF3) and ATP. Here, we show that translocation inhibitors cycloheximide and lactimidomycin inhibited all three reactions. Cycloheximide is a non-competitive inhibitor of both eEF3 and ATP. The inhibition was observed regardless of the way PoTC was prepared with either release factors or puromycin. Paromomycin not only inhibited all three reactions but also re-associated yeast ribosomal subunits. On the other hand, sordarin or fusidic acid, when applied together with eEF2/GTP, specifically inhibited ribosome splitting without blocking of tRNA/mRNA release. From these inhibitor studies, we propose that, in accordance with eEF3\u27s known function in elongation, the release of tRNA via exit site occurs first, then mRNA is released, followed by the splitting of ribosomes during the disassembly of post-termination complexes catalyzed by eEF3 and ATP
Electro-Chemo-Mechanical Failure of Solid Electrolytes Induced by Growth of Internal Lithium Filaments
Growth of lithium (Li) filaments within solid electrolytes, leading to mechanical degradation of the electrolyte and even short circuit of the cell under high current density, is a great barrier to commercialization of solid-state Li-metal batteries. Understanding of this electro-chemo-mechanical phenomenon is hindered by the challenge of tracking local fields inside the solid electrolyte. Here, a multiphysics simulation aiming to investigate evolution of the mechanical failure of the solid electrolyte induced by the internal growth of Li is reported. Visualization of local stress, damage, and crack propagation within the solid electrolyte enables examination of factors dominating the degradation process, including the geometry, number, and size of Li filaments and voids in the electrolyte. Relative damage induced by locally high stress is found to preferentially occur in the region of the electrolyte/Li interface having great fluctuations. A high number density of Li filaments or voids triggers integration of damage and crack networks by enhanced propagation. This model is built on coupling of mechanical and electrochemical processes for internal plating of Li, revealing evolution of multiphysical fields that can barely be captured by the state-of-the-art experimental techniques. Understanding mechanical degradation of solid electrolytes with the presence of Li filaments paves the way to design advanced solid electrolytes for future solid-state Li-metal batteries
Quantum theory of electronic double-slit diffraction
The phenomena of electron, neutron, atomic and molecular diffraction have
been studied by many experiments, and these experiments are explained by some
theoretical works. In this paper, we study electronic double-slit diffraction
with quantum mechanical approach. We can obtain the results: (1) When the slit
width is in the range of we can obtain the obvious
diffraction patterns. (2) when the ratio of , order are missing in
diffraction pattern. (3)When the ratio of , there isn't missing order in diffraction pattern. (4) We
also find a new quantum mechanics effect that the slit thickness has a
large affect to the electronic diffraction patterns. We think all the
predictions in our work can be tested by the electronic double-slit diffraction
experiment.Comment: 9pages, 14figure
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Repurposing tofacitinib as an anti-myeloma therapeutic to reverse growth-promoting effects of the bone marrow microenvironment.
The myeloma bone marrow microenvironment promotes proliferation of malignant plasma cells and resistance to therapy. Activation of JAK/STAT signaling is thought to be a central component of these microenvironment-induced phenotypes. In a prior drug repurposing screen, we identified tofacitinib, a pan-JAK inhibitor Food and Drug Administration (FDA) approved for rheumatoid arthritis, as an agent that may reverse the tumor-stimulating effects of bone marrow mesenchymal stromal cells. Herein, we validated in vitro, in stromal-responsive human myeloma cell lines, and in vivo, in orthotopic disseminated xenograft models of myeloma, that tofacitinib showed efficacy in myeloma models. Furthermore, tofacitinib strongly synergized with venetoclax in coculture with bone marrow stromal cells but not in monoculture. Surprisingly, we found that ruxolitinib, an FDA approved agent targeting JAK1 and JAK2, did not lead to the same anti-myeloma effects. Combination with a novel irreversible JAK3-selective inhibitor also did not enhance ruxolitinib effects. Transcriptome analysis and unbiased phosphoproteomics revealed that bone marrow stromal cells stimulate a JAK/STAT-mediated proliferative program in myeloma cells, and tofacitinib reversed the large majority of these pro-growth signals. Taken together, our results suggest that tofacitinib reverses the growth-promoting effects of the tumor microenvironment. As tofacitinib is already FDA approved, these results can be rapidly translated into potential clinical benefits for myeloma patients
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