337 research outputs found
Spectroscopic Observations of the Outflowing Wind in the Lensed Quasar SDSS J1001+5027
We performed spectroscopic observations of the small-separation lensed quasar
SDSS J1001+5027, whose images have an angular separation , and placed constraints on the physical properties of
gas clouds in the vicinity of the quasar (i.e., in the outflowing wind launched
from the accretion disk). The two cylinders of sight to the two lensed images
go through the same region of the outflowing wind and they become fully
separated with no overlap at a very large distance from the source (
pc). We discovered a clear difference in the profile of the CIV broad
absorption line (BAL) detected in the two lensed images in two observing
epochs. Because the kinematic components in the BAL profile do not vary in
concert, the observed variations cannot be reproduced by a simple change of
ionization state. If the variability is due to gas motion around the background
source (i.e., the continuum source), the corresponding rotational velocity is
km/s, and their distance from the source is
pc assuming Keplerian motion. Among three MgII and three CIV NAL systems that
we detected in the spectra, only the MgII system at shows a
hint of variability in its MgI profile on a rest-frame time scale of days and an obvious velocity shear between the sightlines
whose physical separation is kpc. We interpret this as the result of
motion of a cosmologically intervening absorber, perhaps located in a
foreground galaxy.Comment: 15 pages, including 7 figures; accepted for publication in the
Astrophysical Journa
Polar Order in Quantum Paraelectric SrTiO3-16 and SrTiO3-18 at Low Temperature
Optical second-harmonic generation (SHG) in SrTi16O3 (STO16) and SrTi18O3
(STO18) was investigated using the SHG microscope. While no-biased STO16
exhibits weak and almost temperature-independent SHG signals, a marked SHG is
observed under the electric field in the quantum paraelectric region. In STO18,
strong SHG signals appear spontaneously below 36K. However, neutron and X-ray
diffraction analyses indicate that no structural change appears at low
temperature in STO18, and STO16 under the electric field. By taking into
account the fact that the SHG is sensitive to the local polar-order, the
combined studies reveals that the long-range order of polar phase does not
develop on the both crystals and is frozen in local regions.Comment: soumis a JPSJ -lettr
Junctional adhesion molecule (JAM) binds to PAR-3: a possible mechanism for the recruitment of PAR-3 to tight junctions
At tight junctions (TJs), claudins with four transmembrane domains are incorporated into TJ strands. Junctional adhesion molecule (JAM), which belongs to the immunoglobulin superfamily, is also localized at TJs, but it remains unclear how JAM is integrated into TJs. Immunoreplica electron microscopy revealed that JAM showed an intimate spatial relationship with TJ strands in epithelial cells. In L fibroblasts expressing exogenous JAM, JAM was concentrated at cell–cell adhesion sites, where there were no strand-like structures, but rather characteristic membrane domains free of intramembranous particles were detected. These domains were specifically labeled with anti-JAM polyclonal antibody, suggesting that JAM forms planar aggregates through their lateral self-association. Immunofluorescence microscopy and in vitro binding assays revealed that ZO-1 directly binds to the COOH termini of claudins and JAM at its PDZ1 and PDZ3 domains, respectively. Furthermore, another PDZ-containing polarity-related protein, PAR-3, was directly bound to the COOH terminus of JAM, but not to that of claudins. These findings led to a molecular architectural model for TJs: small aggregates of JAM are tethered to claudin-based strands through ZO-1, and these JAM aggregates recruit PAR-3 to TJs. We also discuss the importance of this model from the perspective of the general molecular mechanisms behind the recruitment of PAR proteins to plasma membranes
Experimental Verification of a One-Dimensional Diffraction-Limit Coronagraph
We performed an experimental verification of a coronagraph. As a result, we
confirmed that, at the focal region where the planetary point spread function
exists, the coronagraph system mitigates the raw contrast of a star-planet
system by at least even for the 1- star-planet
separation. In addition, the verified coronagraph keeps the shapes of the
off-axis point spread functions when the setup has the source angular
separation of 1. The low-order wavefront error and the non-zero
extinction ratio of the linear polarizer may affect the currently confirmed
contrast. The sharpness of the off-axis point spread function generated by the
sub- separated sources is promising for the fiber-based observation
of exoplanets. The coupling efficiency with a single mode fiber exceeds 50%
when the angular separation is greater than 3--4. For
sub- separated sources, the peak positions (obtained with Gaussian
fitting) of the output point spread functions are different from the angular
positions of sources; the peak position moved from about to
as the angular separation of the light source varies from
to . The off-axis throughput including the
fiber-coupling efficiency (with respect to no focal plane mask) is about 40%
for 1- separated sources and 10% for 0.5- separated ones
(excluding the factor of the ratio of pupil aperture width and Lyot stop
width), where we assumed a linear-polarized-light injection. In addition,
because this coronagraph can remove point sources on a line in the sky, it has
another promising application for high-contrast imaging of exoplanets in binary
systems.Comment: 18 pages, 10 figures, accepted for the Publications of the
Astronomical Society of the Pacifi
Enhancement/reduction of biological pump depends on ocean circulation in the sea-ice reduction regions of the Arctic Ocean
http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr08-04/
Broad Efficacy of a Computationally Designed ACE2 Decoy Against SARS-CoV-2 Omicron Variants and Related Viruses In Vitro and In Vivo
Background: The SARS-CoV-2 omicron variant (B.1.1.529) and its sublineages are currently the dominant variants in the United States accounting for 100% of COVID-19 cases. Problem: The S protein receptor-binding domain (RBD), located in the S1 subunit of the S protein, binds the human angiotensin-converting enzyme 2 (hACE2) leading to S1 shedding and proteolytic processing of S2 that is important for membrane fusion and release of viral RNA. Various neutralizing therapeutics including protein minibinders, peptides, monoclonal antibodies, and nanobodies have been developed to block the critical interaction between the RBD and hACE2. However, these therapeutics are often developed against the S protein of wildtype or a specific variant of SARSCoV- 2, making them highly susceptible to mutational escape.1 Solution: A strategy employed by our group includes using sACE2 (soluble dimeric ACE2 that contains both the protease and dimerization domains) with enhanced S RBD affinity to outcompete native ACE2 expressed on host cells, acting as a ‘decoy’ to block the interaction between the RBD and hACE2 (Figure 1). sACE2 has moderate affinity for the S protein (~20 nM)2. Therefore, sACE2 must be engineered (by introducing affinity enhancing mutations) to bind with tighter affinity to outcompete membrane bound ACE2-S interaction and rival the potency of mAbs. These sACE2 derivatives maintain close similarity to the native ACE2 receptor making them extremely resistant to virus escape. Any mutation in the RBD that limits binding to the sACE2 derivative will likely have reduced binding towards native ACE2 receptors potentially making the virus unfit to propagate.https://jdc.jefferson.edu/aoa_research_symposium_posters/1000/thumbnail.jp
Exploring the capability of mayenite (12CaO·7Al₂O₃) as hydrogen storage material
We utilized nanoporous mayenite (12CaO·7Al₂O₃), a cost-effective material, in the hydride state (H⁻) to explore the possibility of its use for hydrogen storage and transportation. Hydrogen desorption occurs by a simple reaction of mayenite with water, and the nanocage structure transforms into a calcium aluminate hydrate. This reaction enables easy desorption of H⁻ ions trapped in the structure, which could allow the use of this material in future portable applications. Additionally, this material is 100% recyclable because the cage structure can be recovered by heat treatment after hydrogen desorption. The presence of hydrogen molecules as H⁻ ions was confirmed by ¹H-NMR, gas chromatography, and neutron diffraction analyses. We confirmed the hydrogen state stability inside the mayenite cage by the first-principles calculations to understand the adsorption mechanism and storage capacity and to provide a key for the use of mayenite as a portable hydrogen storage material. Further, we succeeded in introducing H⁻ directly from OH⁻ by a simple process compared with previous studies that used long treatment durations and required careful control of humidity and oxygen gas to form O₂ species before the introduction of H⁻
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