Publications by authors named "Yoshiyuki Kuroda"

Mesoporous hydrogel electrodes with unique flexible mesopores surrounded by CoOOH nanosheets were prepared the electrochemical deposition of hybrid cobalt hydroxide nanosheets, exhibiting high oxygen evolution reaction activity at a high current density owing to the enhanced mass transport of oxygen molecules.

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Self-repairing catalysts are promising new materials for achieving long lifetime of alkaline water electrolyzers powered by renewable energy. Catalytic nanoparticles dispersed in an electrolyte were deposited on the anode to repair a catalyst layer by electrolysis. A hybrid cobalt hydroxide nanosheet modified with tris(hydroxymethyl)aminomethane on the surface (Co-ns) was used as a catalyst.

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Preparation of high-performance and durable electrocatalysts for anion exchange membrane water electrolysis is a crucial step toward the broad implementation of this technology. Here, we present an easily tunable, one-step hydrothermal method for the preparation of Ni-based (NiX, X = Co, Fe) layered double hydroxide nanoparticles (LDHNPs) for the oxygen evolution reaction (OER), using tris(hydroxymethyl)aminomethane (Tris-NH) for particle growth control. The LDHNPs are used as building blocks of mesoporous mixed metal oxides (MMOs) with a block copolymer template (Pluronic F127), followed by thermal treatment at 250 °C.

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Parameter optimization is a long-standing challenge in various production processes. Particularly, powder film forming processes entail multiscale and multiphysical phenomena, each of which is usually controlled by a combination of several parameters. Therefore, it is difficult to optimize the parameters either by numerical-model-based analysis or by "brute force" experiment-based exploration.

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Background: Hyaluronan (HA), the main component of the extracellular matrix, is involved in tissue elasticity and cell scaffolding, and in progression of conditions such as cancer, inflammation and wound healing. Signaling by G protein coupled receptor (GPCR) activation increases expression of hyaluronan synthase (HAS) and HA production. The β2 adrenergic receptor (β2AR) is a catecholamine-liganded GPCR that is involved in cancer progression and wound healing.

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Various methods for the preparation of inorganic nanosheets have been established and they have contributed to the substantial development of the research on diverse two-dimensional materials. Covalent surface modification of layered metal hydroxides with alkoxy groups is known to effectively weaken the interactions between layers, although the modified ligands are irreversibly immobilized. This study proposes the use of methanol as a removable surface modifier forming monodentate alkoxy bonds to prepare nickel hydroxide nanosheets through hydrolysis.

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Conventional top-down methods for preparing inorganic nanosheets possess fundamental challenges of morphological control. Herein, the direct synthesis of organically modified single-layer magnesium hydroxide nanosheets with narrow size distribution was achieved by the in situ modification of magnesium hydroxide with a tripodal ligand, tris(hydroxymethyl)aminomethane.

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Cristobalite with ordered interstitial dual-sized mesopores was synthesized through the crystallization of silica colloidal crystals composed of monodispersed amorphous silica nanoparticles. An aqueous solution containing both a flux (Na O) and a carbon precursor (an aqueous low-molecular weight phenolic resin) was infiltrated into the interstices of silica colloidal crystals. The organic fraction in the nanocomposite was further polymerized and subsequently carbonized in an Ar flow at 750 °C to reinforce the colloidal crystal structure.

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Hyaluronan synthase 2 (HAS2) is an integral membrane protein composed of multi-membrane-spanning regions and a large intracellular loop (HAS2-loop). We previously examined the effect of phorbol 12-myristate 13-acetate (PMA) and/or 4-methylumbelliferone (4-MU) on the synthesis of hyaluronan (HA) in human skin fibroblasts and found that TPA and 4-MU have opposing effects on HA synthesis by phosphorylation and O-linked β-N-acetylglucosaminylation of HAS2, respectively. In this study, we constructed an expression vector for the HAS2-loop and analyzed its post-translational modification by PMA and 4-MU using mass spectrometry.

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Layered double hydroxides (LDHs) have occupied an important place in the fields of catalysts, electrocatalysts, and fillers, and their applicability can be greatly enhanced by interlayer organic modifications. In contrast to general organic modification based on noncovalent modification using ionic organic species, this study has clarified in situ interlayer covalent modification of LDH nanoparticles (LDHNPs) with the tripodal ligand tris(hydroxymethyl)aminomethane (Tris-NH). Interlayer-modified CoAl LDHNPs were obtained by a one-pot hydrothermal treatment of an aqueous solution containing metal salts and Tris-NH at 180 °C for 24 h.

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We report silicate nanoscrolls composed of only SiO4 tetrahedra with crystalline walls for the first time in this study. The procedure consists of the intercalation of layered octosilicate with dioctadecyldimethylammonium bromide ((C18)2DMABr) and the subsequent solvothermal treatment of the intercalated material in heptane. The walls of the obtained nanoscrolls are crystalline, which originates from layer crystallinity in the pristine silicate.

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The controlled assembly of molecular building blocks enables the rational design of nanomaterials. In this study, two types of cage-type oligosiloxanes with double-three ring (D3R) structures are modified with dimethylsilanol groups to form supramolecular assemblies. One is the siloxane cage derived from Si(OEt)4 (denoted as the Q6 cage), and the other is the organosiloxane cage derived from (EtO)3Si-CH2-Si(OEt)3 (denoted as the T6 cage).

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Controlled assembly of siloxane-based building blocks provides a rational approach toward designed architectures of silica-based porous materials. Here, a non-hydrothermal method to prepare microporous crystals from cage-type oligosiloxanes is reported. The crystals formation occurs through an ordered assembly assisted by hydrogen bonds and subsequent intermolecular connection by silylation.

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Several G protein-coupled receptors are present in lipid rafts. We have shown that most of the P2Y receptor (P2YR) protein is fractionated into lipid rafts in COS 7 cells. In the same cells, about 25-30% of the bradykinin B2 receptor (B2R) protein is also fractionated into lipid rafts.

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Precise size control of layered double hydroxide nanoparticles (LDHNPs) is crucial for their applications in anion exchange, catalysis, and drug delivery systems. Here, we report the synthesis of LDHNPs through a reconstruction method, using tripodal ligands (e.g.

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Many class C G-protein coupled receptors (GPCRs) function as homo- or heterodimers and several class A GPCRs have also been shown to form a homodimer. We expressed human P2Y2 receptor (P2Y2R) in cultured cells and compared SDS-PAGE patterns under reducing and non-reducing conditions. Under non-reducing conditions, approximately half of the P2Y2Rs were electrophoresed as a dimer.

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There are emerging demands for single-digit nanoscale particles in multidisciplinary fields, such as nanomedicine, optics, catalysis, and sensors, to create new functional materials. Here, we report a novel route to prepare silica nanoparticles less than 3 nm in size via the evaporation-induced self-assembly of silicate species and quaternary trialkylmethylammonium surfactants, which usually form reverse micelles. The solvent evaporation induces a local concentration increase and simultaneous polycondensation of silicate species within the hydrophilic region of the surfactant mesophases.

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Layered magnesium hydroxides modified organically with tris(hydroxymethyl)aminomethane (Tris-NH) were directly synthesized from magnesium chloride dissolved in a polar organic solvent, like dimethyl sulfoxide (DMSO), containing a small amount of water. Tris-NH acted as a base for precipitating magnesium hydroxides as well as an organic modifier. In contrast to the case of an aqueous solution, the use of organic solvents substantially increased the degree of modification of layered magnesium hydroxides with Tris-NH owing to the formation of bidentate Mg-O-C linkages by Tris-NH in addition to its tridentate bonding mode.

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Self-organization is a fundamental process for the construction of complex hierarchically ordered nanostructures, which are widespread in biological systems. However, precise control of size, shape, and surface properties is required for self-organization of nanoparticles. Here, we demonstrate a novel self-organization phenomenon mediated by flexible nanospaces in templates.

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Silica sodalite was obtained using topotactic conversion of layered silicate RUB-15 through stepwise processes that consisted of the control of stacking sequence of the layers, interlayer condensation by refluxing, and elimination of intercalated guest species. The interlayer condensation of RUB-15, in which acetic acid was pre-intercalated between the layers to control the stacking sequence, afforded a sodalite framework containing organic guest species by refluxing in N-methylformamide (NMF). The pre-intercalated acetic acid molecules were largely replaced with NMF.

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The thickness of 3-dimensional (3D) mesoporous silica ultrathin films was controlled at a single-nanometer scale by wet-etching. A drop casting method with an aqueous etchant of ammonium fluoride was effective in etching the surfaces of films in the direction perpendicular to their substrates. The decrease in the film thickness depends on the interface tension of etching solutions.

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A single-crystalline macroporous layered silicate was obtained for the first time. Firstly, UTL-type zeolite with macropores was prepared hydrothermally under the presence of acetylene black as a macropore template and the subsequent calcination to remove the template. Double four-membered ring (d4r) units in the UTL framework were selectively dissolved to yield a layered silicate with macropores.

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Mesoporous basic Mg-Al mixed metal oxides (MMOs) with a high surface area and large pore size have been prepared through the assembly of monodispersed layered double hydroxide nanoparticles (LDHNPs) with block copolymer templates. The particle sizes of the LDHNPs were mainly controlled by varying the concentration of tris(hydroxymethyl)aminomethane (THAM), which was used as a surface stabilizing agent. LDHNPs and micelles of a block copolymer (Pluronic F127) were assembled to form a composite.

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P2Y receptor (P2YR) is a G-protein-coupled receptor (GPCR) that couples with Gαq/11 and is stimulated by ATP and UTP. P2YR is involved in pain, proinflammatory changes, and blood pressure control. Some GPCRs are localized in lipid rafts for interaction with other signaling molecules.

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The properties of the outermost surfaces of mesoporous silica thin films are critical in determining their functions. Obtaining information on the presence or absence of silica layers on the film surfaces and on the degree of mesopore opening is essential for applications of surface mesopores. In this study, the outermost surfaces of mesoporous silica thin films with 3-dimensional orthorhombic and 2-dimensional hexagonal structures were observed using ultralow voltage high resolution scanning electron microscopy (HR-SEM) with decelerating optics.

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