12,243 research outputs found
Experimental realization of a highly structured search algorithm
The highly structured search algorithm proposed by Hogg[Phys.Rev.Lett.
80,2473(1998)] is implemented experimentally for the 1-SAT problem in a single
search step by using nuclear magnetic resonance technique with two-qubit
sample. It is the first demonstration of the Hogg's algorithm, and can be
readily extended to solving 1-SAT problem for more qubits in one step if the
appropriate samples possessing more qubits are experimentally feasible.Comment: RevTex, 11 pages + 3 pages of figure
Experimental study of sensitivity-aided application of artificial boundary condition frequencies for damage identification
DMXL2 drives epithelial to mesenchymal transition in hormonal therapy resistant breast cancer through Notch hyper-activation
The acquisition of endocrine therapy resistance in estrogen receptor a (ERa) breast cancer patients represents a major clinical problem. Notch signalling has been extensively linked to breast cancer especially in patients who fail to respond to endocrine therapy. Following activation, Notch intracellular domain is released and enters the nucleus where activates transcription of target genes. The numerous steps that cascade after activation of the receptor complicate using Notch as biomarker. Hence, this warrants the development of reliable indicators of Notch activity. DMXL2 is a novel regulator of Notch signalling not yet investigated in breast cancer. Here, we demonstrate that DMXL2 is overexpressed in a subset of endocrine therapy resistant breast cancer cell lines where it promotes epithelial to mesenchymal transition through hyper-activation of Notch signalling via V-ATPase dependent acidification. Following DMXL2 depletion or treatment with Bafilomycin A1, both EMT targets and Notch signalling pathway significantly decrease. We show for the first time that DMXL2 protein levels are significantly increased in ERa positive breast cancer patients that progress after endocrine therapy. Finally, we demonstrate that DMXL2 is a transmembrane protein with a potential extra-cellular domain. These findings identify DMXL2 as a novel, functional biomarker for ERa positive breast cancer
Inhibition of breast cancer cell invasion by melatonin is mediated through regulation of the p38 mitogen-activated protein kinase signaling pathway
Nicotine-induced phosphorylation of ERK in mouse primary cortical neurons: evidence for involvement of glutamatergic signaling and CaMKII.
Extracellular signal-regulated kinase (ERK) is activated in vivo in a number of brain areas by nicotine and other drugs of abuse. Here we show that nicotine stimulation of cultured mouse cortical neurons leads to a robust induction of ERK phosphorylation that is dependent on nicotine concentration and duration of exposure. Calcium/calmodulin-dependent protein kinase II activity is necessary for nicotine-induced ERK phosphorylation and neither cAMP-dependent protein kinase or protein kinase C appear to be involved. Activity of glutamate receptors, L-type voltage-gated calcium channels, and voltage-gated sodium channels are also required for nicotine-induced ERK phosphorylation. Nicotine-induced ERK phosphorylation was inhibited by high concentrations of mecamylamine, however it was not blocked by other broad nicotinic acetylcholine receptor (nAChR) inhibitors (including hexamethonium and chlorisondamine) or nAChR subtype selective inhibitors (such as methyllycaconitine, alpha-bungarotoxin, dihydro-beta-erythroidine, and α-conotoxin Au1B). In accord with these pharmacological results, nicotine-induced ERK phosphorylation was normal in primary cultures made from β2 or α7 nAChR subunit knockout mice. The α3/beta4 nAChR agonist cytisine did not induce ERK phosphorylation suggesting that α3/β4 nAChRs were not involved in this process. Taken together, these data define a necessary role for glutamatergic signaling and calcium/calmodulin-dependent protein kinase II in nicotine-induced ERK phosphorylation in cortical neurons and do not provide evidence for the involvement of classical nAChRs
Similar ultrafast dynamics of several dissimilar Dirac and Weyl semimetals
Recent years have seen the rapid discovery of solids whose low-energy
electrons have a massless, linear dispersion, such as Weyl, line-node, and
Dirac semimetals. The remarkable optical properties predicted in these
materials show their versatile potential for optoelectronic uses. However,
little is known of their response in the picoseconds after absorbing a photon.
Here we measure the ultrafast dynamics of four materials that share non-trivial
band structure topology but that differ chemically, structurally, and in their
low-energy band structures: ZrSiS, which hosts a Dirac line node and Dirac
points; TaAs and NbP, which are Weyl semimetals; and
SrMnSb, in which Dirac fermions coexist with broken
time-reversal symmetry. After photoexcitation by a short pulse, all four relax
in two stages, first sub-picosecond, and then few-picosecond. Their rapid
relaxation suggests that these and related materials may be suited for optical
switches and fast infrared detectors. The complex change of refractive index
shows that photoexcited carrier populations persist for a few picoseconds
Measuring magnetism in the Milky Way with the Square Kilometre Array
Magnetic fields in the Milky Way are present on a wide variety of sizes and
strengths, influencing many processes in the Galactic ecosystem such as star
formation, gas dynamics, jets, and evolution of supernova remnants or pulsar
wind nebulae. Observation methods are complex and indirect; the most used of
these are a grid of rotation measures of unresolved polarized extragalactic
sources, and broadband polarimetry of diffuse emission. Current studies of
magnetic fields in the Milky Way reveal a global spiral magnetic field with a
significant turbulent component; the limited sample of magnetic field
measurements in discrete objects such as supernova remnants and HII regions
shows a wide variety in field configurations; a few detections of magnetic
fields in Young Stellar Object jets have been published; and the magnetic field
structure in the Galactic Center is still under debate.
The SKA will unravel the 3D structure and configurations of magnetic fields
in the Milky Way on sub-parsec to galaxy scales, including field structure in
the Galactic Center. The global configuration of the Milky Way disk magnetic
field, probed through pulsar RMs, will resolve controversy about reversals in
the Galactic plane. Characteristics of interstellar turbulence can be
determined from the grid of background RMs. We expect to learn to understand
magnetic field structures in protostellar jets, supernova remnants, and other
discrete sources, due to the vast increase in sample sizes possible with the
SKA. This knowledge of magnetic fields in the Milky Way will not only be
crucial in understanding of the evolution and interaction of Galactic
structures, but will also help to define and remove Galactic foregrounds for a
multitude of extragalactic and cosmological studies.Comment: 19 pages, 2 figures; to appear as part of 'Cosmic Magnetism' in
Proceedings 'Advancing Astrophysics with the SKA (AASKA14)', PoS(AASKA14)09
\u27A LABOUR OF LOVE\u27: A KING\u27S COLLEGE LONDON PSYCHIATRY SOCIETY EVENT TO CHALLENGE THE STIGMA ATTACHED TO MENTAL HEALTH PROBLEMS IN POST-NATAL WOMEN
Background: On the 9th October 2000, Dr Daksha Emson, a London based psychiatrist with bipolar affective disorder, tragically
killed herself and her three-month-old baby daughter during a psychotic episode. An independent inquiry into Dr Emson’s death
concluded that mental health stigma in the National Health Service was a factor that contributed to her death. Despite the morbidity and mortality attributed to the stigma attached to post-natal mental health problems there are very few programmes that have been developed to challenge it. King’s College London Undergraduate Psychiatry Society organized an event entitled, ‘A Labour of Love’: Perinatal Mental Health to address this issue. The event included a talk from an expert by experience, a mother who developed post-partum mental health problems.
Design: We conducted a single-arm, pre-post comparison study on participants who attended the KCL Psych Soc event. Validated stigma scales on knowledge (Mental Health Knowledge Schedule (MAKS)), attitudes (Community Attitudes towards the Mentally Ill (CAMI)) and behaviour (Reported and Intended Behaviour Scale (RIBS)) were administered before and immediately after exposure to the event.
Results: 27/27 (100%) of participants recruited responded. There was a statistically significant difference in the pre-MAKS score
compared to the post-MAKS score (p=0.0003), the pre-RIBS score compared to the post-RIBS score (p=0.0068) and in the pre-
CAMI score compared to the post-CAMI score (p=0.0042).
Discussion: There were statistically significant reductions in stigma in the domains of knowledge, attitude and behavior
following exposure to the KCL Psych Soc event and no adverse effects were reported. Our study revealed that a brief intervention made a highly significant impact and maybe useful in challenging the stigma around post-natal mental illness. However, more research in this area is required to determine if the changes are sustained before we can consider rolling out and scaling up such an initiative nationally and internationally
Lattice Dynamics and the High Pressure Equation of State of Au
Elastic constants and zone-boundary phonon frequencies of gold are calculated
by total energy electronic structure methods to twofold compression. A
generalized force constant model is used to interpolate throughout the
Brillouin zone and evaluate moments of the phonon distribution. The moments are
used to calculate the volume dependence of the Gruneisen parameter in the fcc
solid. Using these results with ultrasonic and shock data, we formulate the
complete free energy for solid Au. This free energy is given as a set of closed
form expressions, which are valid to compressions of at least V/V_0 = 0.65 and
temperatures up to melting. Beyond this density, the Hugoniot enters the
solid-liquid mixed phase region. Effects of shock melting on the Hugoniot are
discussed within an approximate model. We compare with proposed standards for
the equation of state to pressures of ~200 GPa. Our result for the room
temperature isotherm is in very good agreement with an earlier standard of
Heinz and Jeanloz.Comment: 13 pages, 8 figures. Accepted by Phys. Rev.
First Detection of Cosmic Structure in the 21-cm Intensity Field
We present the first statistically significant detection of cosmic structure
using broadly distributed hydrogen radio emission. This is accomplished using a
cross correlation with optical galaxies. Statistical noise levels of K
are achieved, unprecedented in this frequency band. This lends support to the
idea that large volumes of the universe can be rapidly mapped without the need
to resolve individual faint galaxies, enabling precise constraints to dark
energy models. We discuss strategies for improved intensity mapping.Comment: 5 pages, 4 figures, submitted to MNRA
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