365 research outputs found

    Analytical control laws for interplanetary solar sail trajectories with constraints

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    An indirect method is used to obtain an analytical control law for a spacecraft with a low-thrust propulsion system which is constituted by a solar sail coupled with a solar electric thruster. Constraints on the control inputs for such as the system need to be taken into account for the design of a control law to avoid reducing control performance, even though the solar electric thruster is employed as an auxiliary system capable of increasing the thrust magnitude of the sailcraft. The aim of this paper is to derive an analytical control law for a system with input constraints. A barrier function is used to analytically obtain a control law without a computationally expensive iterative algorithm. Therefore, using the analytic method presented, a transfer orbit can be readily calculated with an onboard computer. Pontryagin's maximum principle is also used to obtain an optimal control law to compare with the proposed control law. The proposed control law is demonstrated as suitable for an example transfer problem between circular and coplanar orbits

    Three-dimensional formation flying using bifurcating potential fields

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    This paper describes the design of a three-dimensional formation flying guidance and control algorithm for a swarm of autonomous Unmanned Aerial Vehicles (UAVs), using the new approach of bifurcating artificial potential fields. We consider a decentralized control methodology that can create verifiable swarming patterns, which guarantee obstacle and vehicle collision avoidance. Based on a steering and repulsive potential field the algorithm supports flight that can transition between different formation patterns by way of a simple parameter change. The algorithm is applied to linear longitudinal and lateral models of a UAV. An experimental system to demonstrate formation flying is also developed to verify the validity of the proposed control system

    Diphyllobothriasis Associated with Eating Raw Pacific Salmon

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    This tapeworm disease is changing from one of rural populations to one of urban populations worldwide

    Super-chiral vibrational spectroscopy with metasurfaces for high-sensitive identification of alanine enantiomers

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    Chiral nature of an enantiomer can be characterized by circular dichroism (CD) spectroscopy, but such a technique usually suffers from weak signal even with a sophisticated optical instrument. Recent demonstrations of plasmonic metasurfaces showed that chiroptical interaction of molecules can be engineered, thereby greatly simplifying a measurement system with high sensing capability. Here, by exploiting super-chiral field in a metasurface, we experimentally demonstrate high-sensitive vibrational CD spectroscopy of alanine enantiomers, the smallest chiral amino acid. Under linearly polarized excitation, the metasurface consisting of an array of staggered Au nano-rods selectively produces the left- and right-handed super-chiral fields at 1600 cm−1, which spectrally overlaps with the functional group vibrations of alanine. In the Fourier-transform infrared spectrometer measurements, the mirror symmetric CD spectra of D- and L-alanine are clearly observed depending on the handedness of the metasurface, realizing the reliable identification of small chiral molecules. The corresponding numerical simulations reveal the underlying resonant chiroptical interaction of plasmonic modes of the metasurface and vibrational modes of alanine. Our approach demonstrates a high-sensitive vibrational CD spectroscopic technique, opening up a reliable chiral sensing platform for advanced infrared inspection technologies

    子宮内膜症性嚢胞の悪性転化におけるHO-1発現マクロファージの特徴

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    Malignant transformation of endometriosis is a rare and still poorly understood event, but is associated with the distortion of the pro-oxidant and anti-oxidant balance. The aim of the present study was to quantify the numbers of macrophages polarized as M1 or M2 phenotypes and the expression of heme oxygenase (HO)-1 in tissue sections from patients with benign ovarian endometrioma (OE) and its malignant transformation (endometriosis-associated ovarian cancer, EAOC). We performed a retrospective study at the Department of Gynecology, Nara Medical University hospital from December 2012 to March 2015. This study included 53 patients with OE (n = 33) and EAOC (n = 20), and we evaluated polarized functional status of macrophages by immunohistochemical staining of CD68, CD11c, CD163 and HO-1. The number of the M1 phenotype (CD11c+, p = 0.001) and the M2 phenotype (CD163+, p = 0.009) was significantly lower in EAOC patients than in OE patients. Analyzing the correlations between the studied markers, the expression of CD68, CD11c, and CD163 proteins significantly correlated with each other (p < 0.001). The number of M2 phenotypes expressing HO-1 was significantly decreased in the EAOC group, compared with the OE group (P < 0.001), demonstrating sustained downregulation of an antioxidant marker, HO-1, in EAOC. In conclusion, reduced number of M2 macrophages expressing HO-1 may have an important role in promoting malignant transformation of OE.博士(医学)・乙第1434号・令和元年9月27日Copyright © 2018. Published by Elsevier GmbH

    Ghrelin-like peptide with fatty acid modification and O-glycosylation in the red stingray, Dasyatis akajei

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    <p>Abstract</p> <p>Background</p> <p>Ghrelin (GRLN) is now known to be an appetite-stimulating and growth hormone (GH)-releasing peptide that is predominantly synthesized and secreted from the stomachs of various vertebrate species from fish to mammals. Here, we report a GRLN-like peptide (GRLN-LP) in a cartilaginous fish, the red stingray, <it>Dasyatis akajei</it>.</p> <p>Results</p> <p>The purified peptide contains 16 amino acids (GVSFHPQPRS<sup>10</sup>TSKPSA), and the serine residue at position 3 is modified by <it>n</it>-octanoic acid. The modification is the characteristic of GRLN. The six N-terminal amino acid residues (GVSFHP) were identical to another elasmobranch shark GRLN-LP that was recently identified although it had low identity with other GRLN peptides. Therefore, we designated this peptide stingray GRLN-LP. Uniquely, stingray GRLN-LP was <it>O</it>-glycosylated with mucin-type glycan chains [<it>N</it>-acetyl hexosamine (HexNAc)<sub>3 </sub>hexose(Hex)<sub>2</sub>] at threonine at position 11 (Thr-11) or both serine at position 10 (Ser-10) and Thr-11. Removal of the glycan structure by <it>O</it>-glycanase made the <it>in vitro </it>activity of stingray GRLN-LP decreased when it was evaluated by the increase in intracellular Ca<sup>2+ </sup>concentrations using a rat GHS-R1a-expressing cell line, suggesting that the glycan structure plays an important role for maintaining the activity of stingray GRLN-LP.</p> <p>Conclusions</p> <p>This study reveals the structural diversity of GRLN and GRLN-LP in vertebrates.</p
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