158 research outputs found
Hamiltonian decomposition for bulk and surface states
We demonstrate that a tight-binding Hamiltonian with nearest- and
next-nearest-neighbor hopping integrals can be decomposed into bulk and
boundary parts in a general lattice system. The Hamiltonian decomposition
reveals that next nearest-neighbor hopping causes sizable changes in the energy
spectrum of surface states even if the correction to the energy spectrum of
bulk states is negligible. By applying the Hamiltonian decomposition to edge
states in graphene systems, we show that the next nearest-neighbor hopping
stabilizes the edge states.Comment: 5 pages, 4 figure
Gravitational waveforms for 2- and 3-body gravitating systems
Different numbers of self-gravitating particles (in different types of
periodic motion) are most likely to generate very different shapes of
gravitational waves, some of which, however, can be accidentally almost the
same. One such example is a binary and a three-body system for Lagrange's
solution. To track the evolution of these similar waveforms, we define a chirp
mass to the triple system. Thereby, we show that the quadrupole waveforms
cannot distinguish the sources. It is suggested that waveforms with higher
-th multipoles will be important for classification of them (with a
conjecture of for N particles).Comment: 11 pages, 4 figures, accepted for publication in PR
Reversible phase transition in laser-shocked 3Y-TZP ceramics observed via nanosecond time-resolved X-ray diffraction
The high-pressure phase stability of the metastable tetragonal zirconia is
still under debate. The transition dynamics of shocked Y2O3 (3 mol%) stabilized
tetragonal zirconia ceramics under laser-shock compression has been directly
studied using nanosecond time-resolved X-ray diffraction. The martensitic phase
transformation to the monoclinic phase, which is the stable phase for pure
zirconia at ambient pressure and room temperature, has been observed during
compression at 5 GPa within 20 ns without any intermediates. This monoclinic
phase reverts back to the tetragonal phase during pressure release. The results
imply that the stabilization effect due to addition of Y2O3 is negated by the
shear stress under compression.Comment: 11 pages, 4 figures, draf
Superconducting Gap Structure of Spin-Triplet Superconductor Sr_2RuO_4 Studied by Thermal Conductivity
To clarify the superconducting gap structure of the spin-triplet
superconductor Sr_2RuO_4, the in-plane thermal conductivity has been measured
as a function of relative orientations of the thermal flow, the crystal axes,
and a magnetic field rotating within the 2D RuO_2 planes. The in-plane
variation of the thermal conductivity is incompatible with any model with line
nodes vertical to the 2D planes and indicates the existence of horizontal
nodes. These results place strong constraints on models that attempt to explain
the mechanism of the triplet superconductivity.Comment: 5 pages, 4 figures, to be published in Phys. Rev. Let
Artificially Induced Epithelial-Mesenchymal Transition in Surgical Subjects: Its Implications in Clinical and Basic Cancer Research
BACKGROUND: Surgical samples have long been used as important subjects for cancer research. In accordance with an increase of neoadjuvant therapy, biopsy samples have recently become imperative for cancer transcriptome. On the other hand, both biopsy and surgical samples are available for expression profiling for predicting clinical outcome by adjuvant therapy; however, it is still unclear whether surgical sample expression profiles are useful for prediction via biopsy samples, because little has been done about comparative gene expression profiling between the two kinds of samples. METHODOLOGY AND FINDINGS: A total of 166 samples (77 biopsy and 89 surgical) of normal and malignant lesions of the esophagus were analyzed by microarrays. Gene expression profiles were compared between biopsy and surgical samples. Artificially induced epithelial-mesenchymal transition (aiEMT) was found in the surgical samples, and also occurred in mouse esophageal epithelial cell layers under an ischemic condition. Identification of clinically significant subgroups was thought to be disrupted by the disorder of the expression profile through this aiEMT. CONCLUSION AND SIGNIFICANCE: This study will evoke the fundamental misinterpretation including underestimation of the prognostic evaluation power of markers by overestimation of EMT IN past cancer research, and will furnish some advice for the near future as follows: 1) Understanding how long the tissues were under an ischemic condition. 2) Prevalence of biopsy samples for in vivo expression profiling with low biases on basic and clinical research. 3) Checking cancer cell contents and normal- or necrotic-tissue contamination in biopsy samples for prevalence
Liposomal Formulations of Inflammatory Bowel Disease Drugs: Local versus Systemic Drug Delivery in a Rat Model
Based on adherence to intestinal mucosa, intralumenally administered liposomal formulations of 5-aminosalicylate (5-ASA) and 6-mercaptopurine (6-MP) were studied for their potential to enhance local drug delivery to intestinal tissue for the treatment of inflammatory bowel disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41509/1/11095_2005_Article_5376.pd
Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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