86 research outputs found
Unidirectional control of optically induced spin waves
Unidirectional control of optically induced spin waves in a rare-earth iron
garnet crystal is demonstrated. We observed the interference of two spin-wave
packets with different initial phases generated by circularly polarized light
pulses. This interference results in unidirectional propagation if the
spin-wave sources are spaced apart at 1/4 of the wavelength of the spin waves
and the initial phase difference is set to pi/2. The propagating direction of
the spin wave is switched by the polarization helicity of the light pulses.
Moreover, in a numerical simulation, applying more than two spin-wave sources
with a suitable polarization and spot shape, arbitrary manipulation of the spin
wave by the phased array method was replicated
Helical dichroism for hybridized quadrupole plasmon modes in twisted metal nanorods
Helical dichroism (HD), based on the interaction between chiral plasmonic
nanostructures and light with orbital angular momentum (OAM), has attracted
researchers in a wide range of fields from the viewpoint of fundamental physics
and applications. However, the relation between the HD and the excited plasmon
modes has been poorly understood in experiments. Because of the weak chiral
interaction between the chiral structures and OAM light, the structure size
must be much larger than the incident light wavelength to obtain sufficient HD
signal, resulting in the complex superposition of higher-order plasmon modes.
Recently, we experimentally demonstrated that a twisted gold nanorod dimer, one
of the simplest 3D chiral plasmonic structures, exhibits giant circular
dichroism due to strong plasmon coupling between the nanorods, followed by the
hybridization of dipole mode. In this study, we reveal that the HD of this
nanorod dimer appears due to the hybridization of quadrupole plasmon mode
rather than dipole mode. Furthermore, the measurement of the HD signal can be
achieved by using the array of the twisted dimers. The dependence of the HD on
the incident light wavelength exhibits that the HD sign changes around the
quadrupole plasmon resonance, which is in good agreement with the simulation.
These results pave the way to novel insights into the profound understanding of
the light-matter interaction with respect to angular momentum.Comment: 10 pages, 3 figure
Catheterization and embolization of a replaced left hepatic artery via the right gastric artery through the anastomosis: a case report
<p>Abstract</p> <p>Introduction</p> <p>Conversion of multiple hepatic arteries into a single vascular supply is a very important technique for repeat hepatic arterial infusion chemotherapy using an implanted port catheter system. Catheterization of a replaced left hepatic artery arising from a left gastric artery using a percutaneous catheter technique is sometimes difficult, despite the recent development of advanced interventional techniques.</p> <p>Case presentation</p> <p>We present a case of a 70-year-old Japanese man with multiple hepatocellular carcinomas in whom the replaced left hepatic artery arising from the left gastric artery needed to be embolized. After several failed procedures, the replaced left hepatic artery was successfully catheterized and embolized with a microcatheter and microcoils via the right gastric artery through the anastomosis.</p> <p>Conclusion</p> <p>A replaced left hepatic artery arising from a left gastric artery can be catheterized via a right gastric artery by using the appropriate microcatheter and microguidewires, and multiple hepatic arteries can be converted into a single supply.</p
The Quiescent Intracluster Medium in the Core of the Perseus Cluster
Clusters of galaxies are the most massive gravitationally-bound objects in
the Universe and are still forming. They are thus important probes of
cosmological parameters and a host of astrophysical processes. Knowledge of the
dynamics of the pervasive hot gas, which dominates in mass over stars in a
cluster, is a crucial missing ingredient. It can enable new insights into
mechanical energy injection by the central supermassive black hole and the use
of hydrostatic equilibrium for the determination of cluster masses. X-rays from
the core of the Perseus cluster are emitted by the 50 million K diffuse hot
plasma filling its gravitational potential well. The Active Galactic Nucleus of
the central galaxy NGC1275 is pumping jetted energy into the surrounding
intracluster medium, creating buoyant bubbles filled with relativistic plasma.
These likely induce motions in the intracluster medium and heat the inner gas
preventing runaway radiative cooling; a process known as Active Galactic
Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus
cluster core, which reveal a remarkably quiescent atmosphere where the gas has
a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from
the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s
is found across the 60 kpc image of the cluster core. Turbulent pressure
support in the gas is 4% or less of the thermodynamic pressure, with large
scale shear at most doubling that estimate. We infer that total cluster masses
determined from hydrostatic equilibrium in the central regions need little
correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July
The Japanese space gravitational wave antenna; DECIGO
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future
Japanese space gravitational wave antenna. DECIGO is expected to open a new window of
observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing
various mysteries of the universe such as dark energy, formation mechanism of supermassive
black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of
three drag-free spacecraft, whose relative displacements are measured by a differential Fabry–
Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre-
DECIGO first and finally DECIGO in 2024
DECIGO pathfinder
DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected to provide us fruitful insights into the universe, in particular about dark energy, a formation mechanism of supermassive black holes, and the inflation of the universe. Since DECIGO will be an extremely large mission which will formed by three drag-free spacecraft with 1000m separation, it is significant to gain the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. The conceptual design and current status of the first milestone mission, DPF, are reviewed in this article
Genome-Wide Association Study Confirming Association of HLA-DP with Protection against Chronic Hepatitis B and Viral Clearance in Japanese and Korean
Hepatitis B virus (HBV) infection can lead to serious liver diseases, including liver cirrhosis (LC) and hepatocellular carcinoma (HCC); however, about 85–90% of infected individuals become inactive carriers with sustained biochemical remission and very low risk of LC or HCC. To identify host genetic factors contributing to HBV clearance, we conducted genome-wide association studies (GWAS) and replication analysis using samples from HBV carriers and spontaneously HBV-resolved Japanese and Korean individuals. Association analysis in the Japanese and Korean data identified the HLA-DPA1 and HLA-DPB1 genes with Pmeta = 1.89×10−12 for rs3077 and Pmeta = 9.69×10−10 for rs9277542. We also found that the HLA-DPA1 and HLA-DPB1 genes were significantly associated with protective effects against chronic hepatitis B (CHB) in Japanese, Korean and other Asian populations, including Chinese and Thai individuals (Pmeta = 4.40×10−19 for rs3077 and Pmeta = 1.28×10−15 for rs9277542). These results suggest that the associations between the HLA-DP locus and the protective effects against persistent HBV infection and with clearance of HBV were replicated widely in East Asian populations; however, there are no reports of GWAS in Caucasian or African populations. Based on the GWAS in this study, there were no significant SNPs associated with HCC development. To clarify the pathogenesis of CHB and the mechanisms of HBV clearance, further studies are necessary, including functional analyses of the HLA-DP molecule
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