1,795 research outputs found
Irrational vs. rational charge and statistics in two-dimensional quantum systems
We show that quasiparticle excitations with irrational charge and irrational
exchange statistics exist in tight-biding systems described, in the continuum
approximation, by the Dirac equation in (2+1)-dimensional space and time. These
excitations can be deconfined at zero temperature, but when they are, the
charge re-rationalizes to the value 1/2 and the exchange statistics to that of
"quartons" (half-semions).Comment: 4 pages, 2 figure
Driven Graphene as a Tunable Semiconductor with Topological Properties
Controlling the properties of materials by driving them out of equilibrium is
an exciting prospect that has only recently begun to be explored. In this
Letter we give a striking theoretical example of such materials design: a
tunable gap in monolayer graphene is generated by exciting a particular
optical phonon. We show that the system reaches a steady state whose transport
properties are the same as if the system had a static electronic gap,
controllable by the driving amplitude. Moreover, the steady state displays
topological phenomena: there are chiral edge currents, which circulate a
fractional charge e/2 per rotation cycle, with the frequency set by the
optical phonon frequency
Osteopontin mediates tumorigenic transformation of a preneoplastic murine cell line by suppressing anoikis: An Arg‐Gly‐Asp‐dependent‐focal adhesion kinase‐caspase‐8 axis
Osteopontin (OPN), an adhesive, matricellular glycoprotein, is a rate‐limiting factor in tumor promotion of skin carcinogenesis. With a tumor promotion model, the JB6 Cl41.5a cell line, we have shown that suppressing 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA)‐induced OPN expression markedly inhibits TPA‐induced colony formation in soft agar, an assay indicative of tumorigenic transformation. Further, the addition of exogenous OPN promotes colony formation of these cells. These findings support a function of OPN in mediating TPA‐induced neoplastic transformation of JB6 cells. In regard to the mechanism of action by OPN, we hypothesized that, for JB6 cells grown in soft‐agar, secreted OPN induced by TPA stimulates cell proliferation and/or prevents anoikis to facilitate TPA‐induced colony formation. Analyses of cell cycle and cyclin D1 expression, and direct cell counting of JB6 cells treated with OPN indicate that OPN does not stimulate cell proliferation relative to non‐treated controls. Instead, at 24 h, OPN decreases anoikis by 41%, as assessed by annexin V assays. Further, in suspended cells OPN suppresses caspase‐8 activation, which is mediated specifically through its RGD‐cell binding motif that transduces signals through integrin receptors. Transfection studies with wild‐type and mutant focal adhesion kinases (FAK) and Western blot analyses suggest that OPN suppression of caspase‐8 activation is mediated through phosphorylation of FAK at Tyr861. In summary, these studies indicate that induced OPN is a microenvironment modulator that facilitates tumorigenic transformation of JB6 cells by inhibiting anoikis through its RGD‐dependent suppression of caspase‐8 activity, which is mediated in part through the activation of FAK at Tyr861. © 2013 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111135/1/mc22108.pd
Materials Design from Nonequilibrium Steady States: Driven Graphene as a Tunable Semiconductor with Topological Properties
Controlling the properties of materials by driving them out of equilibrium is an exciting prospect that has only recently begun to be explored. In this Letter we give a striking theoretical example of such materials design: a tunable gap in monolayer graphene is generated by exciting a particular optical phonon. We show that the system reaches a steady state whose transport properties are the same as if the system had a static electronic gap, controllable by the driving amplitude. Moreover, the steady state displays topological phenomena: there are chiral edge currents, which circulate a fractional charge e/2 per rotation cycle, with the frequency set by the optical phonon frequency
A New Design for Low Impact Development in Urban Area- Infiltration Pipe and Gravel Pile
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
Discharging patients before 10:00 a.m.: A pilot study
The aim of this study is to increase the morning discharges in a university medical center in Taiwan. Total of 21,670 patients\u27 discharges were analyzed. The early discharge percentage increased from 15% to 19% over the 5-month intervention. The non-elderly group has more earlier hospital discharges than the elderly group
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Multi-scale symbolic entropy analysis provides prognostic prediction in patients receiving extracorporeal life support
Introduction: Extracorporeal life support (ECLS) can temporarily support cardiopulmonary function, and is occasionally used in resuscitation. Multi-scale entropy (MSE) derived from heart rate variability (HRV) is a powerful tool in outcome prediction of patients with cardiovascular diseases. Multi-scale symbolic entropy analysis (MSsE), a new method derived from MSE, mitigates the effect of arrhythmia on analysis. The objective is to evaluate the prognostic value of MSsE in patients receiving ECLS. The primary outcome is death or urgent transplantation during the index admission. Methods: Fifty-seven patients receiving ECLS less than 24 hours and 23 control subjects were enrolled. Digital 24-hour Holter electrocardiograms were recorded and three MSsE parameters (slope 5, Area 6–20, Area 6–40) associated with the multiscale correlation and complexity of heart beat fluctuation were calculated. Results: Patients receiving ECLS had significantly lower value of slope 5, area 6 to 20, and area 6 to 40 than control subjects. During the follow-up period, 29 patients met primary outcome. Age, slope 5, Area 6 to 20, Area 6 to 40, acute physiology and chronic health evaluation II score, multiple organ dysfunction score (MODS), logistic organ dysfunction score (LODS), and myocardial infarction history were significantly associated with primary outcome. Slope 5 showed the greatest discriminatory power. In a net reclassification improvement model, slope 5 significantly improved the predictive power of LODS; Area 6 to 20 and Area 6 to 40 significantly improved the predictive power in MODS. In an integrated discrimination improvement model, slope 5 added significantly to the prediction power of each clinical parameter. Area 6 to 20 and Area 6 to 40 significantly improved the predictive power in sequential organ failure assessment. Conclusions: MSsE provides additional prognostic information in patients receiving ECLS. Electronic supplementary material The online version of this article (doi:10.1186/s13054-014-0548-3) contains supplementary material, which is available to authorized users
Topological phases of extended Su-Schrieffer-Heeger-Hubbard model
Despite extensive studies on the one-dimensional Su-Schrieffer-Heeger-Hubbard
(SSHH) model, the variant incorporating next-nearest neighbour hopping remains
largely unexplored. Here, we investigate the ground-state properties of this
extended SSHH model using the constrained-path auxiliary-field quantum Monte
Carlo (CP-AFQMC) method. We show that this model exhibits rich topological
phases, characterized by robust edge states against interaction. We quantify
the properties of these edge states by analyzing spin correlation and
second-order R\'enyi entanglement entropy. The system exhibits long-range spin
correlation and near-zero R\'enyi entropy at half-filling. Besides, there is a
long-range anti-ferromagnetic order at quarter-filling. Interestingly, an
external magnetic field disrupts this long-range anti-ferromagnetic order,
restoring long-range spin correlation and near-zero R\'enyi entropy.
Furthermore, our work provides a paradigm studying topological properties in
large interacting systems via the CP-AFQMC algorithm.Comment: 16 pages, 11 figure
Autism as a disorder of neural information processing: directions for research and targets for therapy
The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself
Search For Heavy Pointlike Dirac Monopoles
We have searched for central production of a pair of photons with high
transverse energies in collisions at TeV using of data collected with the D\O detector at the Fermilab Tevatron in
1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could
rescatter pairs of nearly real photons into this final state via a box diagram.
We observe no excess of events above background, and set lower 95% C.L. limits
of on the mass of a spin 0, 1/2, or 1 Dirac
monopole.Comment: 12 pages, 4 figure
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