3,583 research outputs found
Diagnosis of Metastatic Breast Cancer to an Intraabdominal Lymph Node by Endoscopic Ultrasound
Breast cancer can present with metastatic disease initially or as a systemic relapse despite seemingly adequate initial treatment. We report a case of suspected metastatic breast cancer to an intraabdominal lymph node based on imaging, which was subsequently confirmed by tissue sampling at the time of endoscopic ultrasound (EUS). While previous studies have shown the utility of EUS in the diagnosis of metastatic breast cancer, this is the first case to our knowledge that describes the use of EUS in diagnosing recurrent breast cancer to an intraabdominal lymph node
On the Semi-centre of a Poisson Algebra
If g is a Lie algebra then the semi-centre of the Poisson algebra S(g) is the subalgebra generated by ad(g) -eigenvectors. In this paper we abstract this definition to the context of integral Poisson algebras. We identify necessary and sufficient conditions for the Poisson semi-centre Asc to be a Poisson algebra graded by its weight spaces. In that situation we show the Poisson semi-centre exhibits many nice properties: the rational Casimirs are quotients of Poisson normal elements and the Poisson Dixmier–Mœglin equivalence holds for Asc
Generalization of the Bound State Model
In the bound state approach the heavy baryons are constructed by binding,
with any orbital angular momentum, the heavy meson multiplet to the nucleon
considered as a soliton in an effective meson theory. We point out that this
picture misses an entire family of states, labeled by a different angular
momentum quantum number, which are expected to exist according to the geometry
of the three-body constituent quark model (for N_C=3). To solve this problem we
propose that the bound state model be generalized to include orbitally excited
heavy mesons bound to the nucleon. In this approach the missing angular
momentum is ``locked-up'' in the excited heavy mesons. In the simplest
dynamical realization of the picture we give conditions on a set of coupling
constants for the binding of the missing heavy baryons of arbitrary spin. The
simplifications made include working in the large M limit, neglecting nucleon
recoil corrections, neglecting mass differences among different heavy spin
multiplets and also neglecting the effects of light vector mesons.Comment: 35 pages (ReVTeX), 2 PostScript Figure
Full-length genomic analysis of korean porcine sapelovirus strains.
Porcine sapelovirus (PSV), a species of the genus Sapelovirus within the family Picornaviridae, is associated with diarrhea, pneumonia, severe neurological disorders, and reproductive failure in pigs. However, the structural features of the complete PSV genome remain largely unknown. To analyze the structural features of PSV genomes, the full-length nucleotide sequences of three Korean PSV strains were determined and analyzed using bioinformatic techniques in comparison with other known PSV strains. The Korean PSV genomes ranged from 7,542 to 7,566 nucleotides excluding the 3' poly(A) tail, and showed the typical picornavirus genome organization; 5'untranslated region (UTR)-L-VP4-VP2-VP3-VP1-2A-2B-2C-3A-3B-3C-3D-3'UTR. Three distinct cis-active RNA elements, the internal ribosome entry site (IRES) in the 5'UTR, a cis-replication element (CRE) in the 2C coding region and 3'UTR were identified and their structures were predicted. Interestingly, the structural features of the CRE and 3'UTR were different between PSV strains. The availability of these first complete genome sequences for PSV strains will facilitate future investigations of the molecular pathogenesis and evolutionary characteristics of PSV
An Allosteric Inhibitor of KRas Identified Using a Barcoded Rapid Assay Microchip Platform
Protein catalyzed capture agents (PCCs) are synthetic antibody surrogates that can target a wide variety of biologically relevant proteins. As a step toward developing a high-throughput PCC pipeline, we report on the preparation of a barcoded rapid assay platform for the analysis of hits from PCC library screens. The platform is constructed by first surface patterning a micrometer scale barcode composed of orthogonal ssDNA strands onto a glass slide. The slide is then partitioned into microwells, each of which contains multiple copies of the full barcode. Biotinylated candidate PCCs from a click screen are assembled onto the barcode stripes using a complementary ssDNA-encoded cysteine-modified streptavidin library. This platform was employed to evaluate candidate PCC ligands identified from an epitope targeted in situ click screen against the two conserved allosteric switch regions of the Kirsten rat sarcoma (KRas) protein. A single microchip was utilized for the simultaneous evaluation of 15 PCC candidate fractions under more than a dozen different assay conditions. The platform also permitted more than a 10-fold savings in time and a more than 100-fold reduction in biological and chemical reagents relative to traditional multiwell plate assays. The best ligand was shown to exhibit an in vitro inhibition constant (IC_(50)) of ∼24 μM
Large-density field theory, viscosity, and "" singularities from string duals
We analyze systems where an effective large-N expansion arises naturally in
gauge theories without a large number of colors: a sufficiently large charge
density alone can produce a perturbative string ('tHooft) expansion. One
example is simply the well-known NS5/F1 system dual to , here viewed as a 5+1 dimensional theory at finite density. This model is
completely stable, and we find that the existing string-theoretic solution of
this model yields two interesting results. First, it indicates that the shear
viscosity is not corrected by effects in this system. For flow
perpendicular to the F1 strings the viscosity to entropy ratio take the usual
value , but for flow parallel to the F1's it vanishes as at low
temperature. Secondly, it encodes singularities in correlation functions coming
from low-frequency modes at a finite value of the momentum along the
directions. This may provide a strong coupling analogue of finite density
condensed matter systems for which fermionic constituents of larger operators
contribute so-called "" singularities. In the NS5/F1 example, stretched
strings on the gravity side play the role of these composite operators. We
explore the analogue for our system of the Luttinger relation between charge
density and the volume bounded by these singular surfaces. This model provides
a clean example where the string-theoretic UV completion of the gravity dual to
a finite density field theory plays a significant and calculable role.Comment: 28 pages. v2: added reference
Nodal fermions in a strongly spin-orbit coupled frustrated pyrochlore superconductor
The pyrochlore lattice, a three-dimensional network of corner-sharing
tetrahedra, is a promising material playground for correlated topological
phases arising from the interplay between spin-orbit coupling (SOC) and
electron-electron interactions. Due to its geometrically frustrated lattice
structure, exotic correlated states on the pyrochlore lattice have been
extensively studied using various spin Hamiltonians in the localized limit. On
the other hand, the topological properties of the electronic structure in the
pyrochlore lattice have rarely been explored, due to the scarcity of pyrochlore
materials in the itinerant paramagnetic limit. Here, we explore the topological
electronic band structure of pyrochlore superconductor RbBi using
angle-resolved photoemission spectroscopy. Thanks to the strong SOC of the Bi
pyrochlore network, we experimentally confirm the existence of
three-dimensional (3D) massless Dirac fermions enforced by nonsymmorphic
symmetry, as well as a 3D quadratic band crossing protected by cubic
crystalline symmetry. Furthermore, we identify an additional 3D linear Dirac
dispersion associated with band inversion protected by threefold rotation
symmetry. These observations reveal the rich non-trivial band topology of
itinerant pyrochlore lattice systems in the strong SOC regime. Through
manipulation of electron correlations and SOC of the frustrated pyrochlore
lattices, this material platform is a natural host for exotic phases of matter,
including the fractionalized quantum spin Hall effect in the topological Mott
insulator phase, as well as axion electrodynamics in the axion insulator phase.Comment: 18 pages, 4 figure
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