High-speed metasurface modulator using critically coupled bimodal plasmonic resonance

Free-space electro-optic (EO) modulators operating at gigahertz and beyond are attractive for a wide range of emerging applications, including high-speed imaging, free-space optical communication, microwave photonics, and diffractive computing. Here we experimentally demonstrate a high-speed plasmonic metasurface EO modulator operating at a near-infrared wavelength range with a gigahertz modulation bandwidth. To achieve efficient intensity modulation of reflected light from an ultrathin metasurface layer, we utilize the bimodal plasmonic resonance inside a subwavelength metal-insulator-metal grating, which is precisely tuned to satisfy the critical coupling condition. As a result, perfect absorption of -27 dB (99.8%) and a high quality (Q) factor of 113 are obtained at a resonant wavelength of 1650 nm. By incorporating an EO polymer inside the grating, we achieve a modulation depth of up to 9.5 dB under an applied voltage of $\pm$30 V. The 3-dB modulation bandwidth is confirmed to be 1.25 GHz, which is primarily limited by the undesired contact resistance. Owing to the high electrical conductivity of metallic gratings and a compact device structure with a minimal parasitic capacitance, the demonstrated device can potentially operate at several tens of gigahertz, which opens up exciting opportunities for ultrahigh-speed active metasurface devices in various applications.Comment: Main text: 18 pages, 3 figures, 39 references Supplementary material: 3 pages, 2 figures

Ultra-broadband surface-normal coherent optical receiver with nanometallic polarizers

A coherent receiver that can demodulate high-speed in-phase and quadrature signals of light is an essential component for optical communication, interconnects, imaging, and computing. Conventional waveguide-based coherent receivers, however, exhibit large footprints, difficulty in coupling a large number of spatial channels efficiently, and limited operating bandwidth imposed by the waveguide-based optical hybrid. Here, we present a surface-normal coherent receiver with nanometallic-grating-based polarizers integrated directly on top of photodetectors without the need for an optical hybrid circuit. Using a fabricated device with the active section occupying a 70-{\mu}m-square footprint, we demonstrate demodulation of high-speed (up to 64 Gbaud) coherent signals in various formats. Moreover, ultra-broadband operation from 1260 nm to 1630 nm is demonstrated, thanks to the wavelength-insensitive nanometallic polarizers. To our knowledge, this is the first demonstration of a surface-normal homodyne optical receiver, which can easily be scaled to a compact two-dimensional arrayed device to receive highly parallelized coherent signals.Comment: 23 pages, 4 figures (main manuscript) + 4 pages, 2 figures (supporting info

Polycomb-Mediated Loss of miR-31 Activates NIK-Dependent NF-κB Pathway in Adult T Cell Leukemia and Other Cancers

SummaryConstitutive NF-κB activation has causative roles in adult T cell leukemia (ATL) caused by HTLV-1 and other cancers. Here, we report a pathway involving Polycomb-mediated miRNA silencing and NF-κB activation. We determine the miRNA signatures and reveal miR-31 loss in primary ATL cells. MiR-31 negatively regulates the noncanonical NF-κB pathway by targeting NF-κB inducing kinase (NIK). Loss of miR-31 therefore triggers oncogenic signaling. In ATL cells, miR-31 level is epigenetically regulated, and aberrant upregulation of Polycomb proteins contribute to miR-31 downregulation in an epigenetic fashion, leading to activation of NF-κB and apoptosis resistance. Furthermore, this emerging circuit operates in other cancers and receptor-initiated NF-κB cascade. Our findings provide a perspective involving the epigenetic program, inflammatory responses, and oncogenic signaling

Acute physiological stress down-regulates mRNA expressions of growth-related genes in coho salmon

Growth and development in fish are regulated to a major extent by growth-related factors, such as liver-derived insulin-like growth factor (IGF) -1 in response to pituitary-secreted growth hormone (GH) binding to the GH receptor (GHR). Here, we report on the changes in the expressions of gh, ghr, and igf1 genes and the circulating levels of GH and IGF-1 proteins in juvenile coho salmon (Oncorhynchus kisutch) in response to handling as an acute physiological stressor. Plasma GH levels were not significantly different between stressed fish and prestressed control. Plasma IGF-1 concentrations in stressed fish 1.5 h post-stress were the same as in control fish, but levels in stressed fish decreased significantly 16 h post-stress. Real-time quantitative PCR (qPCR) analysis showed that ghr mRNA levels in pituitary, liver, and muscle decreased gradually in response to the stressor. After exposure to stress, hepatic igf1 expression transiently increased, whereas levels decreased 16 h post-stress. On the other hand, the pituitary gh mRNA level did not change in response to the stressor. These observations indicate that expression of gh, ghr, and igf1 responded differently to stress. Our results show that acute physiological stress can mainly down-regulate the expressions of growth-related genes in coho salmon in vivo. This study also suggests that a relationship between the neuroendocrine stress response and growth-related factors exists in fish.Peer reviewed: YesNRC publication: Ye

Organic solid-state distributed feedback dye laser with a nonmorphological modification grating

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 77(17):2641-2643 (2000) and may be found at https://doi.org/10.1063/1.1320034 .ArticleAPPLIED PHYSICS LETTERS. 77(17):2641-2643 (2000)journal articl

Examination of Selective Low-pressure Fine Needle Aspiration Cytology Under Ultrasound Guidance

Cytology by fine-needle cytology is indispensable for diagnosing head and neck tumor, especially for thyroid nodule. There are two methods of fine needle cytology; one of fine-needle aspiration cytology (FNAC and another of fine-needle non-aspiration cytology (FNNAC). These previous procedures has each disadvantage such as the mixing of blood or low yield of cells. We proposed a new technique: selective low-pressure fine needle aspiration cytology (SLOP-FNAC) to overcome the backwards of previous procedures. We used the scoring system by Mair et al. to evaluate smear quality of specimens obtained with FNNAC and SLOP-FNAC. SLOP-FNAC smears exhibited higher scores in amount of cellular material, degree of cellular degeneration and cell yield, and retention of appropriate architecture compared to FNNAC smears. The SLOP-FNAC smears scored significantly higher for amount of cellular material and retention of appropriate architecture evaluated (P = 0.0261 and P = 0.0024, Student’s t-test). SLOP-FNAC may be a useful cell sampling technique that reduces blood contamination while securing a high cell yield with maintaining tissue structure

PETREL for Astrophysics and Carbon Business

A multi-purpose 50kg class microsatellite hosting astrophysical mission and earth remote sensing, PETREL , will be launched in 2023. In the night side, PETREL observe the ultra-violet sky with a wide-field telescope covering 50 deg^2 for surveying transient objects related to supernovae, tidal disruption events, and gravitational wave events. Our UV telescope can detect the early phase UV emission from a neutron star merger occurred within 150 Mpc. In addition to the satellite observation, PETREL sends a detection alert including the coordinate and brightness of the UV transient to the ground via the real time communication network within several minutes after detection to conduct follow-up observations with the collaborating ground based observatories over the world. In the day side, PETREL observes the surface of the earth by using the tunable multi-spectral cameras and a ultra-compact hyperspectral camera. Our potential targets are the tropical forests (Green Carbon) and coastal zones (Blue Carbon) in the tropical areas to evaluating the global biological carbon strages. For this purpose PETREL will conduct multiple scale mapping collaborating with drones and small aircraft not only satellite. The obtained data will be used for academical research and for business applications. The technical difficulty of this satellite is that carries out multi-purpose with different requirements, such as astronomical observations which requires a quite high attitude stability and the earth observations requiring a high pointing accuracy, with limited resources. If it is possible, a novel small satellite system or a business style can be realized that can share the payload with academia and industry. PETREL has been adopted as Innovative Satellite Technology Demonstration Program No.3 led by JAXA, and development is underway with the aim of launching in FY2023

ケイチョクガタ ノウセイマヒ ニヨル チュウコウネン シタイ フジユウシャ ノ チョウキ カシ キンリョク トレーニング ニオケル ケイネンテキ ヘンドウ

As targeting the physically handicapped person who can have their own walking, the effect of long−term isokinetic muscle exercise training was verified from the point of view of the aging, and the following results were obtained. 1) In the muscle strength of ankle joint, its value of 50 years old person were significantly higher, compared with the value of 40 years old person. 2) In the muscle strength of knee joint, its value of 40 years old person were significantly higher, compared with the value of 50 years old person. 3) No significant differences were observed in the numerical values between the 40s and 50s old person. From the above result, the following possibility was also shown that the training effect for the handicap improvement is higher than the muscle weakness associated with aging in the person having the cerebral palsy. However, the further verification is needed about the relation between the handicap improvement by the muscle training and the muscle weakness associated with aging