Publications by authors named "Koichi Eguchi"

Heteropolyanions (HPAs) are known as the candidate for an anode redox mediator for redox flow polymer electrolyte fuel cells (PEFCs). The electrochemical properties of HPAs differ depending on the transition elements and heteroatoms in HPAs. For example, heteropolytungstate anions (W-HPAs), in which the transition element is tungsten, have a lower one-electron reduction potential than other HPAs.

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The extracellular accumulation of aggregated amyloid-β (Aβ) in the brain leads to the early pathology of Alzheimer's disease (AD). The administration of exogenous plant-type ceramides into AD model mice can promote the release of neuronal exosomes, a subtype of extracellular vesicles, that can mediate Aβ clearance. In vitro studies showed that the length of fatty acids in mammalian-type ceramides is crucial for promoting neuronal exosome release.

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Although eyelid reconstruction by transplanting an autologous free tarsoconjunctival graft (FTG) is a well-established technique, few studies have examined the postoperative course of FTG transplantation for East Asian eyelids, including those of Japanese patients. Therefore, this study investigated complication and reoperation rates after FTG transplantation in the reconstruction of East Asian (Japanese) eyelids. This study included 42 eyelids wherein posterior lobe reconstruction after resection of a malignant tumour of the eyelid was performed by FTG transplantation between 2007 and 2019 at Niigata University Medical and Dental Hospital.

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Hypogonadism, associated with low levels of testosterone synthesis, has been implicated in several diseases. Recently, the quest for natural alternatives to prevent and treat hypogonadism has gained increasing research interest. To this end, the present study explored the effect of -allyl cysteine (SAC), a characteristic organosulfur compound in aged-garlic extract, on testosterone production.

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Supported Ni catalysts are active in CO2 methanation. It is important to understand the reaction mechanism for the development of highly-active catalysts. In this study, we investigated the reaction pathways of CO2 methanation over Ni/Y2O3 and Ni/Al2O3 based on the adsorbates observed by diffuse reflectance infrared Fourier transform spectroscopy.

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Ceramides, a type of sphingolipid, are cell membrane components and lipid mediators that modulate a variety of cell functions. In plants, ceramides are mostly present in a glucosylated glucosylceramide (GlcCer) form. We previously showed that oral administration of konjac-derived GlcCer to a mouse model of Alzheimer's disease reduced brain amyloid-β and amyloid plaques.

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Ammonia decomposition has attracted increasing attention as a promising process for the on-site generation of hydrogen. In this study, Ni catalysts supported on perovskite-type oxides (ABO) were prepared and the activity for ammonia decomposition was examined. The Ni/ANbO (A = Na and K) and Ni/AEMnO (AE = Ca, Sr, and Ba) catalysts were less effective for this reaction.

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Over the last few decades, because of the significant development of anion exchange membranes, increasing efforts have been devoted the realization of anion exchange membrane fuel cells (AEMFCs) that operate with the supply of hydrogen generated on-site. In this paper, ammonia was selected as a hydrogen source, following which the effect of conceivable impurities, unreacted NH and atmospheric CO, on the performance of AEMFCs was established. As expected, we show that these impurities worsen the performance of AEMFCs significantly.

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In this study, the heteropolyacids of H3+xPVxMO12-xO40 (x = 0, 2, and 3) were applied as redox mediators for the oxygen reduction reaction in polymer electrolyte fuel cells, of which the cathode is free from the usage of noble metals such as Pt/C. In this system, the electrochemical reduction of heteropolyacid over the carbon cathode and the subsequent reoxidation of the partially reduced heteropolyacid by exposure to the dissolved oxygen in the regenerator are important processes for continuous power generation. Thus, the redox properties of catholytes containing these heteropolyacids were investigated in detail.

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The electrochemical oxidation of 2-propanol over Pt and Pd electrodes was evaluated in alkaline media. Linear sweep voltammograms (LSVs), chronoamperograms (CAs), and simultaneous time-resolved attenuated total reflection infrared (ATR-IR) spectra of both electrodes were obtained in a 0.25 M KOH solution containing 1 M 2-propanol.

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In recent years, solid oxide fuel cells fueled with ammonia have been attracting intensive attention. In this work, ammonia fuel was supplied to the Ni/yttria-stabilized zirconia (YSZ) cermet anode at 600 and 700 °C, and the change of electrochemical performance and microstructure under the open-circuit state was studied in detail. The influence of ammonia exposure on the microstructure of Ni was also investigated by using Ni/YSZ powder and Ni film deposited on a YSZ disk.

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The electrochemical oxidation of ammonia over Pt electrode in alkaline aqueous solutions was studied by in situ attenuated total reflection infrared (ATR-IR) spectroscopy. In 0.1 M NH3-1 M KOH, the band ascribable to the HNH bending mode of adsorbed NH3 was confirmed at 1662-1674 cm(-1) in the potential range of 0.

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In this study, Ni/BaCe0.75Y0.25O3-δ (Ni/BCY25) was investigated as an anode for direct ammonia-fueled solid oxide fuel cells.

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The dedicator of cytokinesis (DOCK) family proteins that are conserved in a wide variety of species are known as DOCK1-DOCK11 in mammals. The Sponge (Spg) is a Drosophila counterpart to the mammalian DOCK3. Specific knockdown of spg by pannir-GAL4 or apterous-GAL4 driver in wing discs induced split thorax phenotype in adults.

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A 67-year-old man was admitted to our hospital because of a large liver tumor revealed by ultrasonography. Laboratory data showed increased serum levels of alpha-fetoprotein (AFP) and des-gamma-carboxy prothrombin (DCP), which are tumor markers for hepatocellular carcinoma. In addition, the serum cholesterol level was extremely high.

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The Drosophila sponge (spg)/CG31048 gene belongs to the dedicator of cytokinesis (DOCK) family genes that are conserved in a wide variety of species. DOCK family members are known as DOCK1-DOCK11 in mammals. Although DOCK1 and DOCK2 involve neurite elongation and immunocyte differentiation, respectively, the functions of other DOCK family members are not fully understood.

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Objective: Recent studies have reported that duodenal heterotopic gastric mucosa (HGM) has been observed in 8.9% of patients who undergo esophagogastroduodenoscopy. However, there are few reports concerning the endoscopic and endoscopic ultrasound characteristics of submucosal tumour-like HGM in the duodenum.

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A 59-year-old man was admitted to our hospital because of watery diarrhea and bloody stool lasting for a month. The patient had been a habitual smoker, smoking 25 cigarettes/day for 35 years. However, he had recently stopped smoking since a giant bulla in the left lung had been found.

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Background: Orbital lymphangioma can result in ocular emergencies due to acute enlargement, leading to painful proptosis, compressive optic neuropathy, exposure keratopathy, restrictive ocular motility and increased intraocular pressure. Treatment methods and clinical courses of two cases with orbital lymphangioma are reported, one with orbital decompression therapy and the other with intralesional injection of OK-432 therapy. CASE 1: An 8-year-old girl had multilocular cystic orbital intracornal lymphangioma.

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A 45-year-old man was admitted to our hospital because of chronic hepatitis C and a large liver tumor accompanied by increased serum levels of alpha-fetoprotein (AFP) and des-gamma-carboxy prothrombin (DCP), the tumor markers for hepatocellular carcinoma. Endoscopic examination revealed advanced gastric cancer. Biopsy specimens of the stomach and liver showed gastric adenocarcinoma and its metastasis to the liver.

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