161 research outputs found

    Oxygen reduction characteristics of several valve metal oxide electrodes in HClO(4) solution

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    In the search for active cathode catalysts for polymer electrolyte fuel cells (PEFCs) using inexpensive materials several valve metal oxide electrodes TiO(x) ZrO(x), and TaO(x) with corresponding binary oxide electrodes were selected for the evaluation of catalytic activity for oxygen reduction reaction (ORR) by means of cyclic voltammetry in 0 1 M HClO(4) at 60 C These oxide electrodes were prepared mainly by the dip-coating method on a titanium plate substrate at a temperature between 400 degrees C and 500 degrees C and were characterized by scanning electron microscopy (SEM) X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS) Among the oxide-coated electrodes investigated Ti(0) (7)Zr(0) (3)O(x)/Ti provided the highest ORR specific activity with an onset potential E(ORR) of 0 86V vs RHE during the cathodic potential sweep Fine TaO(x) particles prepared as an extension of the dip-coating method showed very high catalytic activity determined by means of hydrodynamic voltammetry in 0 1 M HClO(4) at 30 degrees C with an E(ORR) of 0 90 V vs RHEArticleELECTROCHIMICA ACTAjournal articl

    A gas-diffusion cathode coated with oxide-catalyst for polymer electrolyte fuel cells using neither platinum catalyst nor carbon catalyst-support

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    To overcome the fundamental disadvantages of conventional cathodes for polymer electrolyte fuel cells (PEFCs), such as dissolution and migration of platinum-based catalysts and consumption of the carbon catalyst-support, a substantially novel gas-diffusion cathode has been proposed. The electrode was made of a porous oxide catalyst, which was coated on the inner and outer surfaces of a macro-porous titanium sheet substrate, using neither a platinum catalyst nor carbon catalyst-support. The suitability of this cathode for PEFCs, tested using a highly porous iridium oxide strongly coated on the macro-porous titanium sheet substrate, was confirmed by successful power generation. The gas-diffusion electrode functioned not only as the cathode but also as an anode of a PEFC.ArticleELECTROCHIMICA ACTA. 105:224-229 (2013)journal articl

    Peptidyl prolyl isomerase Pin1-inhibitory activity of d-glutamic and d-aspartic acid derivatives bearing a cyclic aliphatic amine moiety

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    AbstractPin1 is a peptidyl prolyl isomerase that specifically catalyzes cis–trans isomerization of phosphorylated Thr/Ser-Pro peptide bonds in substrate proteins and peptides. Pin1 is involved in many important cellular processes, including cancer progression, so it is a potential target of cancer therapy. We designed and synthesized a novel series of Pin1 inhibitors based on a glutamic acid or aspartic acid scaffold bearing an aromatic moiety to provide a hydrophobic surface and a cyclic aliphatic amine moiety with affinity for the proline-binding site of Pin1. Glutamic acid derivatives bearing cycloalkylamino and phenylthiazole groups showed potent Pin1-inhibitory activity comparable with that of known inhibitor VER-1. The results indicate that steric interaction of the cyclic alkyl amine moiety with binding site residues plays a key role in enhancing Pin1-inhibitory activity

    脳幹部転移性脳腫瘍に対する寡分割定位放射線治療の治療成績

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    Background: To assess the neuroimaging and clinical outcomes in patients with brainstem metastasis (BSM) treated with linac-based fractionated stereotactic radiotherapy (fSRT) with a micro-multileaf collimator. Methods: Between May 2007 and January 2017, 24 patients (15 male and 9 female) with BSM (25 lesions: midbrain, 10; pons, 13; and medulla oblongata, 2) were consecutively treated with linac-based fSRT. BSM originated from the lung (n = 18, 75.0%), colon (n = 3, 12.5%), and breast (n = 3, 12.5%). The median patient age was 67.0 (range: 42-80) years. Recursive partition analysis classified 2 patients as class I, 17 as class II, and 5 as class III. Overall survival was calculated using the Kaplan-Meier method. Results: Tumor volume ranged from 0.01 to 7.49 cm3 (median: 0.233 cm3), and patients were treated with a dose of 24-40 Gy in 7-13 fractions. The median OS was 9 months after fSRT (95% confidence interval 4.104-13.896). Large tumor volume, presence of brainstem-related symptoms, poor pretreatment Karnofsky performance status, and recursive partition analysis class III were significantly associated with low overall survival. Tumor volume decreased in 18 metastatic lesions, remained stable in 6, and increased in 1. No patient exhibited permanent radiation injury. Grade 2 nausea and vomiting according to the Common Terminology Criteria for Adverse Events 4.0 occurred in 1 patient who received corticosteroids. Conclusions: Linac-based fSRT with a micro-multileaf collimator delivered in the doses of 24-40 Gy in 7-13 fractions is a safe and effective local therapy for patients with BSM.博士(医学)・乙第1450号・令和2年3月16日Copyright © 2019 Elsevier Inc. All rights reserved

    転移性脳腫瘍の倍量造影剤投与における、分割投与と単回投与の病変描出能の比較

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    PURPOSE: As stereotactic radiotherapy (SRT) becomes widespread, precise information including number, location, and margin of lesions is required when magnetic resonance (MR) imaging of brain metastasis is performed. We compare methods using 2 separate injections and a single injection for the administration of a double dose of contrast medium for contrastenhanced MR imaging. MATERIALS AND METHODS: We divided 40 patients with brain metastasis into 2 groups of 20 patients. Group A received 2 separate injections (0.2 + 0.2 mL/kg) of contrast medium (gadoteridol); Group B received a single injection of the same total dose (0.4 mL/kg). Group A underwent spin echo (SE) T1-weighted imaging (T1WI) and magnetization prepared rapid acquisition with gradient echo sequence (MPRAGE) after each injection, and Group B underwent the same MR studies at the same timing as Group A. We evaluated the number, signal-to-noise ratio (SNR), diameter, margin delineation, and volume of lesions and compared them between early and delayed studies by the 2 methods. RESULTS: The number of detected lesions was largest in delayed studies of MPRAGE in both groups. The SNR of the lesions was statistically lower in early studies of Group A than other studies. Delayed studies of Group B showed statistically better margin delineation than other studies on both SE-T1WI and MPRAGE studies. Diameter and enhanced volume were statistically significantly larger on delayed phase than early phase in both groups. CONCLUSION: Use of a single injection of double-dose contrast medium and longer delay time may improve margin delineation of lesions for the study of brain metastasis. Enhanced volume was larger on delayed phase, and it may influence selection of therapeutic strategy.博士(医学)・乙第1356号・平成27年3月16日Copyright © 2014 by Japanese Society for Magnetic Resonance in Medicine著作権は日本磁気共鳴医学会に帰属日本磁気共鳴医学会及び著者(共著者も含む)の許諾を得て登

    Boulder size and shape distributions on asteroid Ryugu

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    In 2018, the Japanese spacecraft Hayabusa2, arrived at the small asteroid Ryugu. The surface of this C-type asteroid is covered with numerous boulders whose size and shape distributions are investigated in this study. Using a few hundred Optical Navigation Camera (ONC) images with a pixel scale of approximately 0.65 m, we focus on boulders greater than 5m in diameter. Smaller boulders are also considered using five arbitrarily chosen ONC close-up images with pixel scales ranging from 0.7 to 6 cm. Across the entire surface area (~2.7 km2) of Ryugu, nearly 4400 boulders larger than 5m were identified. Boulders appear to be uniformly distributed across the entire surface, with some slight differences in latitude and longitude. At ~50 km−2, the number density of boulders larger than 20m is twice as large as on asteroid Itokawa (or Bennu). The apparent shapes of Ryugu's boulders resemble laboratory impact fragments, with larger boulders being more elongated. The ratio of the total volume of boulders larger than 5m to the total excavated volume of craters larger than 20m on Ryugu can be estimated to be ~94%, which is comparatively high. These observations strongly support the hypothesis that most boulders found on Ryugu resulted from the catastrophic disruption of Ryugu's larger parent body, as described in previous papers (Watanabe et al., 2019; Sugita et al.,2019). The cumulative size distribution of boulders larger than 5 m has a power-index of −2.65 ± 0.05, which is comparatively shallow compared with other asteroids visited by spacecraft. For boulders smaller than 4 m, the power-index is even shallower and ranges from −1.65 ± 0.05 to −2.01 ± 0.06. This particularly shallow power-index implies that some boulders are buried in Ryugu's regolith. Based on our observations, we suggest that boulders near the equator might have been buried by the migration of finer material and, as a result, the number density of boulders larger than 5 m in the equatorial region is lower than at higher latitudes

    Characterization of a New Saccharomyces cerevisiae Isolated From Hibiscus Flower and Its Mutant With L-Leucine Accumulation for Awamori Brewing

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    Since flavors of alcoholic beverages produced in fermentation process are affected mainly by yeast metabolism, the isolation and breeding of yeasts have contributed to the alcoholic beverage industry. To produce awamori, a traditional spirit (distilled alcoholic beverage) with unique flavors made from steamed rice in Okinawa, Japan, it is necessary to optimize yeast strains for a diversity of tastes and flavors with established qualities. Two categories of flavors are characteristic of awamori; initial scented fruity flavors and sweet flavors that arise with aging. Here we isolated a novel strain of Saccharomyces cerevisiae from hibiscus flowers in Okinawa, HC02-5-2, that produces high levels of alcohol. The whole-genome information revealed that strain HC02-5-2 is contiguous to wine yeast strains in a phylogenic tree. This strain also exhibited a high productivity of 4-vinyl guaiacol (4-VG), which is a precursor of vanillin known as a key flavor of aged awamori. Although conventional awamori yeast strain 101-18, which possesses the FDC1 pseudogene does not produce 4-VG, strain HC02-5-2, which has the intact PAD1 and FDC1 genes, has an advantage for use in a novel kind of awamori. To increase the contents of initial scented fruity flavors, such as isoamyl alcohol and isoamyl acetate, we attempted to breed strain HC02-5-2 targeting the L-leucine synthetic pathway by conventional mutagenesis. In mutant strain T25 with L-leucine accumulation, we found a hetero allelic mutation in the LEU4 gene encoding the Gly516Ser variant α-isopropylmalate synthase (IPMS). IPMS activity of the Gly516Ser variant was less sensitive to feedback inhibition by L-leucine, leading to intracellular L-leucine accumulation. In a laboratory-scale test, awamori brewed with strain T25 showed higher concentrations of isoamyl alcohol and isoamyl acetate than that brewed with strain HC02-5-2. Such a combinatorial approach to yeast isolation, with whole-genome analysis and metabolism-focused breeding, has the potentials to vary the quality of alcoholic beverages

    Identification of candidate molecular targets of the novel antineoplastic antimitotic NP-10

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    We previously reported the identification of a novel antimitotic agent with carbazole and benzohydrazide structures: N′-[(9-ethyl-9H-carbazol-3-yl)methylene]-2-iodobenzohydrazide (code number NP-10). However, the mechanism(s) underlying the cancer cell-selective inhibition of mitotic progression by NP-10 remains unclear. Here, we identified NP-10-interacting proteins by affinity purification from HeLa cell lysates using NP-10-immobilized beads followed by mass spectrometry. The results showed that several mitosis-associated factors specifically bind to active NP-10, but not to an inactive NP-10 derivative. Among them, NUP155 and importin β may be involved in NP-10-mediated mitotic arrest. Because NP-10 did not show antitumor activity in vivo in a previous study, we synthesized 19 NP-10 derivatives to identify more effective NP-10-related compounds. HMI83-2, an NP-10-related compound with a Cl moiety, inhibited HCT116 cell tumor formation in nude mice without significant loss of body weight, suggesting that HMI83-2 is a promising lead compound for the development of novel antimitotic agents

    Isolated congenital megacystis without intestinal obstruction: A mild variant of chronic intestinal pseudoobstruction syndrome?

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    Megacystis is frequently involved with chronic intestinal pseudoobstruction syndrome; however, isolated megacystis without intestinal obstruction is extremely rare. We present the case of a female patient with isolated congenital megacystis without severe intestinal obstruction. In this case, barium enema did not reveal any significant findings; however, histologic evaluation of her rectum showed hypoganglionosis of the submucous and myenteric plexuses. These findings indicate that this case may be a mild variant of chronic intestinal pseudoobstruction syndrome. The presence of megacystis should alert the physician to the possibility of chronic intestinal pseudoobstruction syndrome. © 2011 Elsevier Inc. All rights reserved
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