1,190 research outputs found
Atroposelective formation of dibenz[c,e]azepines via intramolecular direct arylation with centre-axis chirality transfer
Syncytial Hepatitis of Tilapia (Oreochromis niloticus L.) is Associated With Orthomyxovirus-Like Virions in Hepatocytes
Using transmission electron microscopy (TEM), the presented work expands on the ultrastructural findings of an earlier report on “syncytial hepatitis,” a novel disease of tilapia (SHT). Briefly, TEM confirmed the presence of an orthomyxovirus-like virus within the diseased hepatocytes but not within the endothelium. This was supported by observing extracellular and intracellular (mostly intraendosomal), 60–100 nm round virions with a trilaminar capsid containing up to 7 electron-dense aggregates. Other patterns noted included enveloped or filamentous virions and virion-containing cytoplasmic membrane folds, suggestive of endocytosis. Patterns atypical for orthymyxovirus included the formation of syncytia and the presence of virions within the perinuclear cisternae (suspected to be the Golgi apparatus). The ultrastructural morphology of SHT-associated virions is similar to that previously reported for tilapia lake virus (TiLV). A genetic homology was investigated using the available reverse transcriptase polymerase chain reaction (RT-PCR) probes for TiLV and comparing clinically sick with clinically normal fish and negative controls. By RT-PCR analysis, viral nucleic acid was detected only in diseased fish. Taken together, these findings strongly suggest that a virus is causally associated with SHT, that this virus shares ultrastructural features with orthomyxoviruses, and it presents with partial genetic homology with TiLV (190 nucleotides). </jats:p
In vivo targeted DamID identifies CHD8 genomic targets in fetal mouse brain.
Funder: Royal SocietyFunder: Agouron InstituteGenetic studies of autism have revealed causal roles for chromatin remodeling gene mutations. Chromodomain helicase DNA binding protein 8 (CHD8) encodes a chromatin remodeler with significant de novo mutation rates in sporadic autism. However, relationships between CHD8 genomic function and autism-relevant biology remain poorly elucidated. Published studies utilizing ChIP-seq to map CHD8 protein-DNA interactions have high variability, consistent with technical challenges and limitations associated with this method. Thus, complementary approaches are needed to establish CHD8 genomic targets and regulatory functions in developing brain. We used in utero CHD8 Targeted DamID followed by sequencing (TaDa-seq) to characterize CHD8 binding in embryonic mouse cortex. CHD8 TaDa-seq reproduced interaction patterns observed from ChIP-seq and further highlighted CHD8 distal interactions associated with neuronal loci. This study establishes TaDa-seq as a useful alternative for mapping protein-DNA interactions in vivo and provides insights into the regulatory targets of CHD8 and autism-relevant pathophysiology associated with CHD8 mutations
Anomalous electric conductions in KSbO3-type metallic rhenium oxides
Single crystals of KSbO3-type rhenium oxides, La4Re6Orho(T)=\rho_{0}+AT^{n}(n \approx 1.6)$ in
a wide temperature range between 5 K and 300 K, which is extraordinary for
three-dimensional metals without strong electron correlations. The resistivity
of Bi3Re3O11 shows an anomaly around at 50 K, where the magnetic susceptibility
also detects a deviation from ordinary Pauli paramagnetism.Comment: 13 pages, 7 figures. J. Phys. Soc. Japan, in pres
Nonsynchronous, episodic incision: Evidence of threshold exceedance and complex response as controls of terrace formation
Terrace sequences can represent regional or continental scale factors such as climatic fluctuations, neotectonic activity, and base-level change. However, they can also reflect random incision events brought about by local scale, geomorphic threshold exceedance, and subsequent complex response. This study explores the formative processes of three discontinuous, but adjacent, late Pleistocene to late Holocene stepterrace sequences in southeastern Australia. Correlation of river terrace fills was undertaken by comparing terrace remnants based on topography, morphology, sedimentology, stratigraphy, and chronology. A geomorphic model of floodplain abandonment and terrace formation for this valley setting is presented. Most of southeastern Australia has shown no evidence of tectonic uplift during the late Quaternary. Bedrock bars on the Hunter River isolate the study reach from downstream base-level changes. The nonsynchronous, episodic behavior of incision events in this catchment strongly indicates that climate is not a dominant control on terrace formation. With the exclusion of climatic fluctuations, tectonic uplift and base-level change as causes of incision, catastrophic floods, and the exceedance of geomorphic thresholds emerge as the dominant controls of terrace formation. Crow
Unquenched large orbital magnetic moment in NiO
Magnetic properties of NiO are investigated by incorporating the spin-orbit
interaction in the LSDA+U scheme. It is found that the large part of orbital
moment remains unquenched in NiO. The orbital moment contributes about mu_L =
0.29 mu_B to the total magnetic moment of M = 1.93 mu_B, as leads to the
orbital-to-spin angular momentum ratio of L/S = 0.36. The theoretical values
are in good agreement with recent magnetic X-ray scattering measurements.Comment: 4 pages, 2 figure
Formation of topological defects in gauge field theories
When a symmetry gets spontaneously broken in a phase transition, topological
defects are typically formed. The theoretical picture of how this happens in a
breakdown of a global symmetry, the Kibble-Zurek mechanism, is well established
and has been tested in various condensed matter experiments. However, from the
viewpoint of particle physics and cosmology, gauge field theories are more
relevant than global theories. In recent years, there have been significant
advances in the theory of defect formation in gauge field theories, which make
precise predictions possible, and in experimental techniques that can be used
to test these predictions in superconductor experiments. This opens up the
possibility of carrying out relatively simple and controlled experiments, in
which the non-equilibrium phase transition dynamics of gauge field theories can
be studied. This will have a significant impact on our understanding of phase
transitions in the early universe and in heavy ion collider experiments. In
this paper, I review the current status of the theory and the experiments in
which it can be tested.Comment: Review article, 43 pages, 7 figures. Minor changes, some references
added. Final version to appear in IJMP
Exact and Truncated Dynamics in Nonequilibrium Field Theory
Nonperturbative dynamics of quantum fields out of equilibrium is often
described by the time evolution of a hierarchy of correlation functions, using
approximation methods such as Hartree, large N, and nPI-effective action
techniques. These truncation schemes can be implemented equally well in a
classical statistical system, where results can be tested by comparison with
the complete nonlinear evolution obtained by numerical methods. For a 1+1
dimensional scalar field we find that the early-time behaviour is reproduced
qualitatively by the Hartree dynamics. The inclusion of direct scattering
improves this to the quantitative level. We show that the emergence of
nonthermal temperature profiles at intermediate times can be understood in
terms of the fixed points of the evolution equations in the Hartree
approximation. The form of the profile depends explicitly on the initial
ensemble. While the truncated evolution equations do not seem to be able to get
away from the fixed point, the full nonlinear evolution shows thermalization
with a (surprisingly) slow relaxation.Comment: 30 pages with 12 eps figures, minor changes; to appear in Phys.Rev.
A narrow, edge-on disk resolved around HD 106906 with SPHERE
HD~106906AB is so far the only young binary system around which a planet has
been imaged and a debris disk evidenced thanks to a strong IR excess. As such,
it represents a unique opportunity to study the dynamics of young planetary
systems. We aim at further investigating the close (tens of au scales)
environment of the HD~106906AB system. We used the extreme AO fed, high
contrast imager SPHERE recently installed on the VLT to observe HD~106906. Both
the IRDIS imager and the Integral Field Spectrometer were used. We discovered a
very inclined, ring-like disk at a distance of 65~au from the star. The disk
shows a strong brightness asymmetry with respect to its semi-major axis. It
shows a smooth outer edge, compatible with ejection of small grains by the
stellar radiation pressure. We show furthermore that the planet's projected
position is significantly above the disk's PA. Given the determined disk
inclination, it is not excluded though that the planet could still orbit within
the disk plane if at a large separation (2000--3000 au). We identified several
additional point sources in the SPHERE/IRDIS field-of-view, that appear to be
background objects. We compare this system with other debris disks sharing
similarities, and we briefly discuss the present results in the framework of
dynamical evolution.Comment: 7 pages, 6 figures, accepted by Astronomy & Astrophysic
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