20 results match your criteria: "Osaka University 2-1 Yamada-oka[Affiliation]"

Electrocatalytic and thermocatalytic CO conversions provide promising routes to realize global carbon neutrality, and the development of corresponding advanced catalysts is important but challenging. Hollow-structured carbon (HSC) materials with striking features, including unique cavity structure, good permeability, large surface area, and readily functionalizable surface, are flexible platforms for designing high-performance catalysts. In this review, the topics range from the accurate design of HSC materials to specific electrocatalytic and thermocatalytic CO conversion applications, aiming to address the drawbacks of conventional catalysts, such as sluggish reaction kinetics, inadequate selectivity, and poor stability.

View Article and Find Full Text PDF

We developed self-assembled peptides containing a partial amyloid β protein sequence and a metal-coordination site. The amyloid fibril-copper complexes exhibited excellent reactivity and moderate enantioselectivity in Michael addition reactions with 2-azachalcone and dimethylmalonate. The catalytic amyloids were characterized using various measurements to confirm their amyloid-like nanofibre structures.

View Article and Find Full Text PDF

A strong, tough, and stable adhesion system used in various environments must be developed. A long-lasting adhesion system should effectively perform in the following five aspects: adhesion strength, toughness, energy dissipation property, self-restoration property, and creep resistance property. However, these properties are difficult to balance using conventional adhesives.

View Article and Find Full Text PDF

Ternary and quaternary semiconductor quantum dots (QDs) are candidates for cadmium-free alternatives. Among these, semiconductors containing elements from groups 11, 13, and 16 (, I-III-VI) are attracting increasing attention since they are direct semiconductors whose bandgap energies in the bulk state are tunable between visible and near infrared. The quaternary system of alloys consisting of silver indium sulfide (AgInS; bandgap energy: = 1.

View Article and Find Full Text PDF

Photoluminescent carbon dots (CDs) possess several advantages, which include high stability and a non-toxicity that are essential in different applications such as catalysis, drug delivery, and sensors. The presence of heteroatoms modifies their physicochemical characteristics. In this work, a combination of CDs is manufactured utilizing a solvothermal technique using citric acid and thiourea.

View Article and Find Full Text PDF

Pt-nanoparticle-supported graphene nanoplatelets (Pt/GNPs) and multiwalled carbon nanotube composite (Pt/MWCNTs) electrocatalysts for the oxygen reduction reaction (ORR) can be prepared using a one-pot method through the pyrolytic decomposition of the platinum precursor, platinum(ii) bis(acetylacetonate) (Pt(acac)) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([Cmim][TfN]) or ,,-trimethyl--propylammonium bis(trifluoromethanesulfonyl)amide ([N][TfN]) ionic liquids (ILs) with the target sp carbon support. In this one-pot pyrolysis method, which does not require any reagents to reduce Pt metal precursors or stabilize Pt nanoparticles, Pt nanoparticles are readily immobilized onto the sp surface by a thin IL layer formed at the interface, which can work as a binder. We used three types of sp carbon materials with different geometric shapes (graphene nanoplatelets with <3 (GNPs-3) and 18-24 layers (GNPs-20) and multiwalled carbon nanotubes (MWCNTs)) to investigate Pt nanoparticle formation and anchoring.

View Article and Find Full Text PDF

Production of methanol from anthropogenic carbon dioxide (CO) is a promising chemical process that can alleviate both the environmental burden and the dependence on fossil fuels. In catalytic CO hydrogenation to methanol, reduction of CO to intermediate species is generally considered to be a crucial step. It is of great significance to design and develop advanced heterogeneous catalysts and to engineer the surface structures to promote CO-to-methanol conversion.

View Article and Find Full Text PDF

Single-molecule laser nanospectroscopy with micro-electron volt energy resolution.

Science

July 2021

Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.

Ways to characterize and control excited states at the single-molecule and atomic levels are needed to exploit excitation-triggered energy-conversion processes. Here, we present a single-molecule spectroscopic method with micro-electron volt energy and submolecular-spatial resolution using laser driving of nanocavity plasmons to induce molecular luminescence in scanning tunneling microscopy. This tunable and monochromatic nanoprobe allows state-selective characterization of the energy levels and linewidths of individual electronic and vibrational quantum states of a single molecule.

View Article and Find Full Text PDF

We report the first preparation of small gold-nickel (AuNi) bimetallic nanoparticles (<5 nm) supported on titania by the method of galvanic replacement reaction (GRR), evidenced by the replacement of Ni atoms by Au atoms according to the stoichiometry of the reaction. We showed that this preparation method allowed not only the control of the gold and nickel contents in the samples, but also the formation of small bimetallic nanoparticles with strained core-shell structures, as revealed by aberration-corrected scanning transmission electron microscopy in combination with energy-dispersive X-ray spectroscopy mapping. The catalytic characterization by the probe reaction of semi-hydrogenation of butadiene showed that the resulting nickel-based nanocatalysts containing a small amount of gold exhibited higher selectivity to butenes than pure nickel catalysts and a high level of activity, closer to that of pure nickel catalysts than to that of pure gold catalysts.

View Article and Find Full Text PDF

Nanoparticles composed of molybdenum oxide, MoO , were successfully prepared by room-temperature ionic liquid (RTIL)/metal sputtering followed by heat treatment. Hydroxyl groups in RTIL molecules retarded the coalescence between MoO NPs during heat treatment at 473 K in air, while the oxidation state of Mo species in MoO nanoparticles (NPs) could be modified by changing the heat treatment time. An LSPR peak was observed at 840 nm in the near-IR region for MoO NPs of 55 nm or larger in size that were annealed in a hydroxyl-functionalized RTIL.

View Article and Find Full Text PDF

Rhodium dinuclear complexes (1-3) with azulene moieties as equatorial ligands were obtained by reacting Rh (OAc) with guaiazulene-2-carboxylic acid, azulene-2-carboxylic acid, and azulene-1-carboxylic acid, respectively. The molecular structures in their crystalline states were determined by X-ray diffraction to be 1 ⋅ (H O) , 1 ⋅ (MeCN) , 2 ⋅ (MeCN) , and 3 ⋅ (DMF) , which were coordinated with the crystallization solvent at the axial positions. Among these, the crystal packing of 1 ⋅ (H O) , 1 ⋅ (MeCN) , and 3 ⋅ (DMF) revealed the formation of one-dimensional stacked chains nearly along the axial direction and of two-dimensional stacked sheets along the equatorial direction.

View Article and Find Full Text PDF
Article Synopsis
  • - This study introduces a new electrochemiluminescence method for precisely measuring creatine kinase MB (CK-MB) using a special nanocomposite made from carbon nano-onions and metal nanoparticles like gold and iron oxide.
  • - The immunosensor was created by layering the nanocomposite on an electrode, attaching an antibody, and using a specific luminophore and co-reactant for optimal light emission during testing.
  • - It demonstrated an impressive detection range from 50 fg/mL to 10 ng/mL with a very low detection limit of 5 fg/mL, along with excellent selectivity and stability for potential clinical application in human serum samples.
View Article and Find Full Text PDF

A synthetic route to embed aggregation-induced-emission-(AIE)-active luminophores in polycarbonates (PCs) in various ratios is reported. The AIE-active monomer is based on the structure of 9,10-bis(piperidyl)anthracene. The obtained PCs display good film-forming properties, similar to those observed in poly(bisphenol A carbonate) (Ba-PC).

View Article and Find Full Text PDF

Platinum single-atom adsorption on graphene: a density functional theory study.

Nanoscale Adv

March 2019

Department of Precision Science and Technology, Graduate School of Engineering, Osaka University 2-1 Yamada-oka, Suita Osaka 565-0871 Japan

Single-atom catalysis, which utilizes single atoms as active sites, is one of the most promising ways to enhance the catalytic activity and to reduce the amount of precious metals used. Platinum atoms deposited on graphene are reported to show enhanced catalytic activity for some chemical reactions, methanol oxidation in direct methanol fuel cells. However, the precise atomic structure, the key to understand the origin of the improved catalytic activity, is yet to be clarified.

View Article and Find Full Text PDF

Bisphosphonates are commonly used for the treatment of bone disorders such as osteoporosis; however, the mechanism by which they affect the dynamics of living mature osteoclasts in vivo remains unknown. Here, we describe the short-term effects of different bisphosphonates on controlling the bone resorptive activity of mature osteoclasts in living bone tissues of mice using intravital two-photon microscopy with a pH-sensing chemical fluorescent probe. Three types of nitrogen-containing bisphosphonates, risedronate, alendronate, and minodronate, inhibited osteoclastic acidification during osteoporotic conditions just 12 hours after i.

View Article and Find Full Text PDF

Nanometer-sized extracellular matrix coating on polymer-based scaffold for tissue engineering applications.

J Biomed Mater Res A

January 2016

Department of Bioengineering, 301 Rhodes Engineering Research Center, Clemson University, Clemson, South Carolina, 29634-0905.

Article Synopsis
  • Surface modification is key for improving cell adhesion to synthetic scaffolds in tissue engineering, with a focus on a new layer-by-layer approach using fibronectin and gelatin on electrospun poly(carbonate urethane)urea (PCUU) scaffolds.
  • The resulting PCUU(FN-G) scaffolds, created by immersing in fibronectin and gelatin solutions, maintained their 3D structure and significantly improved the adhesion and growth of bladder smooth muscle cells compared to uncoated scaffolds.
  • This technique shows promise for enhancing tissue engineering applications, with potential for adaptation to other polymer-based systems due to its simple physical adsorption method for forming FN-G layers.
View Article and Find Full Text PDF

Improvement of efficiency and temperature control of induction heating vapor source on electron cyclotron resonance ion source.

Rev Sci Instrum

February 2012

Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University 2-1 Yamada-oka, Suita-shi, Osaka 565-0871, Japan.

An electron cyclotron resonance ion source (ECRIS) is used to generate multicharged ions for many kinds of the fields. We have developed an evaporator by using induction heating method that can generate pure vapor from solid state materials in ECRIS. We develop the new matching and protecting circuit by which we can precisely control the temperature of the induction heating evaporator.

View Article and Find Full Text PDF

N-linked glycan structures of human lactoferrin produced by transgenic rice.

Biosci Biotechnol Biochem

December 2004

International Center for Biotechnology, Osaka University 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.

Human lactoferrin was produced in genetically engineered rice. N-linked glycan structures of recombinant human lactoferrin were determined. The oligosaccharides liberated by hydrazinolysis were labeled with 2-aminopyridine (PA).

View Article and Find Full Text PDF

Aliphatic Hydroxylation by a Bis(µ-oxo)dicopper(III) Complex.

Angew Chem Int Ed Engl

January 2000

Department of Material and Life Science Graduate School of Engineering, Osaka University 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan).

By using molecular oxygen bis(µ-oxo)dicopper(III) complexes can be produced from Cu(I) complexes with ligand L(X) (L(X)=p-substituted N-ethyl-N-[2-(2-pyridyl)ethyl]-2-phenylethylamine; X=OMe, Me, H, Cl, NO(2)) in which the benzylic position of the ligand is activated and hydroxylated by the Cu(2)O(2) core (see reaction scheme). Detailed characterization of this new C-H bond activation reaction by the bis(µ-oxo)dicopper(III) core reveals important information on the fundamental chemistry underlying copper monooxygenase reactivity.

View Article and Find Full Text PDF