457 research outputs found

    Robust Focusing using Orientation Code Matching

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    This paper proposes a novel scheme for image focusing by introducing a new focus measure based on self-matching methods. A unique pencil-shaped profile is identified by comparing the similarity between all patterns extracted around the same position in each scene. Based on this profile, a new criterion function called Complementary Pencil Volume (hereafter CPV) is defined to evaluate focused or defocused scenes based on similarity rate of self-matching, which visually represents the volume of a pencil-shaped profile. Among matching methods, Orientation Code Matching (hereafter OCM) is recommended due to its invariance with regards to illumination and contrasts. Several experiments using a telecentric lens are implemented to demonstrate the efficiency of proposed measures. Outstandingly, comparing Orientation Code Matching-based (hereafter OCM-based) focus measure with conventional focus measures shows that OCM-based focus measure is robust against changes of illuminations and contrast. Using this method, depth is measured by comparing the focused and defocused region in the scenes both under high and low illumination conditions

    Thermal Conductivity in the Bose-Einstein Condensed State of Triplons in the Bond-Alternating Spin-Chain System Pb2V3O9

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    In order to clarify the origin of the enhancement of the thermal conductivity in the Bose-Einstein Condensed (BEC) state of field-induced triplons, we have measured the thermal conductivity along the [101] direction parallel to spin-chains, kappa[101]kappa_{\|[101]}, and perpendicular to spin-chains, kappa[101]kappa_{\perp[101]}, of the S=1/2 bond-alternating spin-chain system Pb2V3O9 in magnetic fields up to 14 T. With increasing field at 3 K, it has been found that both kappa[101]kappa_{\|[101]} and kappa[101]kappa_{\perp[101]} are suppressed in the gapped normal state in low fields. In the BEC state of field-induced triplons in high fields, on the other hand, kappa[101]kappa_{\|[101]} is enhanced with increasing field, while kappa[101]kappa_{\perp[101]} is suppressed. That is, the thermal conductivity along the direction, where the magnetic interaction is strong, is markedly enhanced in the BEC state. Accordingly, our results suggest that the enhancement of kappa[101]kappa_{\|[101]} in the BEC state is caused by the enhancement of the thermal conductivity due to triplons on the basis of the two-fluid model, as in the case of the superfluid state of liquid 4He.Comment: 5 pages, 3 figure

    Vision-Based Displacement Sensor for Monitoring Dynamic Response Using Robust Object Search Algorithm

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    This paper develops a vision-based displacement measurement system for remote monitoring of vibration of large-size structures such as bridges and buildings. The system consists of one or multiple video cameras and a notebook computer. With a telescopic lens, the camera placed at a stationary point away from a structure captures images of an object on the structure. The structural displacement is computed in real time through processing the captured images. A robust object search algorithm developed in this paper enables accurate measurement of the displacement by tracking existing features on the structure without requiring a conventional target panel to be installed on the structure. A sub-pixel technique is also proposed to further reduce measurement errors cost-effectively. The efficacy of the vision system in remote measurement of dynamic displacements was demonstrated through a shaking table test and a field experiment on a long-span bridge

    Gene transfer of GLT-1, a glial glutamate transporter, into the spinal cord by recombinant adenovirus attenuates inflammatory and neuropathic pain in rats

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    <p>Abstract</p> <p>Background</p> <p>The glial glutamate transporter GLT-1 is abundantly expressed in astrocytes and is crucial for glutamate removal from the synaptic cleft. Decreases in glutamate uptake activity and expression of spinal glutamate transporters are reported in animal models of pathological pain. However, the lack of available specific inhibitors and/or activators for GLT-1 makes it difficult to determine the roles of spinal GLT-1 in inflammatory and neuropathic pain. In this study, we examined the effect of gene transfer of GLT-1 into the spinal cord with recombinant adenoviruses on the inflammatory and neuropathic pain in rats.</p> <p>Results</p> <p>Intraspinal infusion of adenoviral vectors expressing the GLT-1 gene increased GLT-1 expression in the spinal cord 2–21 days after the infusion. Transgene expression was primarily localized to astrocytes. The spinal GLT-1 gene transfer had no effect on acute mechanical and thermal nociceptive responses in naive rats, whereas it significantly reduced the inflammatory mechanical hyperalgesia induced by hindlimb intraplantar injection of carrageenan/kaolin. Spinal GLT-1 gene transfer 7 days before partial sciatic nerve ligation recovered the extent of the spinal GLT-1 expression in the membrane fraction that was decreased following the nerve ligation, and prevented the induction of tactile allodynia. However, the partial sciatic nerve ligation-induced allodynia was not reversed when the adenoviruses were infused 7 or 14 days after the nerve ligation.</p> <p>Conclusion</p> <p>These results suggest that overexpression of GLT-1 on astrocytes in the spinal cord by recombinant adenoviruses attenuates the induction, but not maintenance, of inflammatory and neuropathic pain, probably by preventing the induction of central sensitization, without affecting acute pain sensation. Upregulation or functional enhancement of spinal GLT-1 could be a novel strategy for the prevention of pathological pain.</p

    Raphe AMPA receptors and nicotinic acetylcholine receptors mediate ketamine-induced serotonin release in the rat prefrontal cortex.

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    Several lines of evidence indicate that ketamine has a rapid antidepressant-like effect in rodents and humans, but underlying mechanisms are unclear. In the present study, we investigated the effect of ketamine on serotonin (5-HT) release in the rat prefrontal cortex by in vivo microdialysis. A subcutaneous administration of ketamine (5 and 25 mg/kg) significantly increased the prefrontal 5-HT level in a dose-dependent manner, which was attenuated by local injection of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) antagonists into the dorsal raphe nucleus (DRN). Direct stimulation of AMPARs in the DRN significantly increased prefrontal 5-HT level, while intra-DRN injection of ketamine (36.5 nmol) had no effect. Furthermore, intra-DRN injection of an α 4 β 2-nicotinic acetylcholine receptor (nAChR) antagonist, dihydro-β-erythroidine (10 nmol), significantly attenuated the subcutaneous ketamine-induced increase in prefrontal 5-HT levels. These results suggest that AMPARs and α 4 β 2-nAChRs in the DRN play a key role in the ketamine-induced 5-HT release in the prefrontal cortex

    Oxygen Isotope Exchange Between Molten Silicate Spherules and Ambient Water Vapor with Nonzero Relative Velocity: Implication for Chondrule Formation Environment

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    Oxygen isotope compositions of chondrules reflect the environment of chondrule formation and its spatial and temporal variations. Here, we present a theoretical model of oxygen isotope exchange reaction between molten silicate spherules and ambient water vapor with finite relative velocity. We found a new phenomenon, that is, mass-dependent fractionation caused by isotope exchange with ambient vapor moving with nonzero relative velocity. We also discussed the plausible condition for chondrule formation from the point of view of oxygen isotope compositions. Our findings indicate that the relative velocity between chondrules and ambient vapor would be lower than several 100 m/s when chondrules crystallized.Comment: 15 pages, 8 figures. Accepted for publication in Icaru

    Molecular cloning of haploid germ cell-specific tektin cDNA and analysis of the protein in mouse testis

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    AbstractTektins are a class of proteins that form filamentous polymers in the walls of ciliary and flagellar microtubules. We report here the molecular cloning of a new member of the tektin family, tektin-t, identified from a mouse haploid germ cell-specific cDNA library. Tektin-t mRNA encodes a protein of 430 deduced amino acids possessing RSNVELCRD, the conserved sequence of tektin family proteins. Western blotting showed a single band having a molecular weight of 86 kDa in the mouse testis. Immunohistochemistry of the testis showed that tektin-t is localized in the flagella of elongating spermatids from developmental step 15 to maturity
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