Publications by authors named "Yuji Higaki"

Article Synopsis
  • Advanced materials that control water properties are becoming increasingly important in material design.
  • This study focused on the effects of microphase separation in certain aqueous solutions of diblock copolymers, namely poly(carboxybetaine methacrylate) and poly(sulfobetaine methacrylate).
  • Techniques like differential scanning calorimetry and X-ray emission spectroscopy revealed that the water in these solutions experiences significant cold crystallization and changes in hydrogen bonding.
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We present an atypical case of risedronate-induced chronic fever in an 85-year-old woman with Parkinson's disease, with a dosage regimen of 17.5 mg/week. Our patient had been administered an analgesic/antipyretic drug, acetaminophen, at a rate of 600 mg/day for treatment of a vertebral fracture that occurred relatively frequently, which might have masked the fever caused by risedronate.

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Article Synopsis
  • Molecular assemblies responsive to pH and saccharide concentration, specifically polymeric micelles incorporating phenylboronic acids (PBAs), show great potential in biomedicine.
  • This study examines how zwitterions influence the acidity constant related to the collapse and glucose sensitivity of a diblock copolymer micelle composed of polyacrylamides with PBA and zwitterionic carboxybetaine.
  • The presence of glucose affects the pH at which the polymeric micelles dissociate, highlighting that zwitterionic interactions can enhance the design of biomaterials that respond to environmental changes.
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Objective Due to the increasing elderly population and number of dementia patients, the current number of psychiatrists and neurologists remains insufficient to treat dementia in Japan. Therefore, a simple method for accurately performing a dementia diagnosis, including that of primary care physicians, is sought in clinical practice. Methods A retrospective study was conducted on patients who made their first visit due to amnesia between October 2020 and October 2022.

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Objective: Glyoxylic acid (GA) is widely used as a straight perming agent for hair care products, however, advanced GA penetration-enhancing agents are desired due to the peculiar odour and hair colour fading caused by the continuous use of GA products. Hence, it is important to develop a penetration-enhancing agent that helps minimize the GA concentration. We have found that the combined use of GA and glycolic acid (GCA) has a strong hair straightening effect.

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Polyethyleneglycol 12 mol / polydimethylsiloxane co-polymer (PEG-12 dimethicone) is a type of polyether modified silicone (PEMS), which can form a lamellar liquid crystalline phase, and is widely used in cosmetics. The structural changes of PEG-12 dimethicone caused by water contents as well as shear flow were evaluated using simultaneous measurements of rheology and small angle neutron scattering (Rheo-SANS) and neutron reflectometry (NR). At high PEG-12 dimethicone concentrations (≥ 36 wt%), a reorientation of plate-like lamellar structures were observed and the neutral orientation was the most favorable.

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The creation of self-healing polymers from commodity olefins is of great interest and importance but has remained a challenge to date. We report here for the first time the synthesis of self-healing polymers by catalyst-controlled polymerization of a simple commodity diene, isoprene. We found that polyisoprenes having an appropriate mixture (ca.

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Artificial cartilages build up a highly lubricious system with the harmony of biomacromolecules and water. Bioconjugate thin films composed of a zwitterionic poly(carboxybetaine methacrylate) (PCB) brush platform and bovine serum albumin (BSA) were designed. BSA conjugation to the PCB brush chains was achieved by carbodiimide chemistry to give PCB brush/BSA conjugate films.

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A polymer electrolyte brush is a reasonable platform to confine water molecules within a nanoscopic area to study their role in the function of interacting media because of their adjustable nanospace and charge by changing the in-plane density and side chains of the brush. Here, we demonstrate how the in-plane spacing of cationic polymer brush chains, poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMTAC), affects the hydrogen bond configuration of incorporated water using soft X-ray emission spectroscopy. At the critical in-plane density σ = 0.

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Article Synopsis
  • Transformable double hydrophilic block copolymers can effectively function as smart, biocompatible macromolecular systems.
  • The spontaneous assembly of these copolymers, specifically composed of PCB2 and PSB4, occurs in salt-free water due to specific interactions between zwitterions.
  • Modulation of the copolymer aggregates is influenced by the addition of particular nondetergent zwitterions, and their disruption effectiveness varies based on the molecular structure and charge characteristics of the zwitterions used.
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The terpolymerization of a non-polar olefin (such as ethylene) and two different polar functional olefins in a controlled fashion is of great interest and importance but has hardly been explored to date. We report for the first time the terpolymerization of ethylene (E) and two different methoxyaryl-substituted propylenes (A P=hexylanisyl propylene; A P=methoxynaphthyl propylene or methoxypyrenyl propylene) by a half-sandwich scandium catalyst. The terpolymerization took place in a sequence-controlled fashion, affording unique multi-block copolymers composed of two different ethylene-alt-methoxyarylpropylene sequences E-alt-A P (soft segments) and E-alt-A P (hard segments) and relatively short ethylene-ethylene (EE) blocks (crystalline segments).

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Article Synopsis
  • A study was conducted on the molecular mechanisms of cononsolvency in poly[2-(methacryloyloxy)ethyl phosphorylcholine] (PMPC) within ethanol-water mixtures, focusing on a unique coil-to-globule-to-coil transition of polymer chains.
  • The research combined statistical mechanical models for hydrogen bonding with neutron reflectivity experiments to explore how different solvent interactions influence PMPC's behavior.
  • Results showed that at an ethanol volume fraction of 0.90, PMPC chains aggregated and became solvated with more water than the bulk solution, with strong evidence supporting the role of cooperative solvation and competitive hydrogen bonding in this process.
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Marine mussels efficiently adhere under wet conditions by precisely controlling the hierarchical structure of the adhesive plaque through sequential mussel foot protein secretion in the foot-tip cavity. Chemical analysis of the non-uniform mussel plaque morphology has been performed using spectromicroscopy; however, the mesoscopic morphology has not been elucidated yet because of the limited spatial resolution of conventional chemical imaging techniques. We investigated the chemical speciation in the non-uniform mussel plaque morphology employing scanning transmission soft X-ray spectromicroscopy (STXM).

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Light produced by synchrotron radiation (SR) is much brighter than that produced by conventional laboratory X-ray sources. The photon energy of SR X-ray ranges from soft and tender X-rays to hard X-rays. Moreover, X-rays become element sensitive with decreasing photon energy.

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Polyzwitterions have emerged as a new class of antifouling materials alternating poly(ethylene glycol). The exemplary biopassivation and lubrication behaviors are often attributed to the particular chemical structure of zwitterions, which involve a large dipole moment of the charged groups and a neutral net charge, while the hydration state and dynamics also associate with these characteristics. Polymer brushes composed of surface-tethered polyzwitterion chains produced by surface-initiated controlled radical polymerization have been developed as thin films which exhibit excellent antifouling and lubrication properties.

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Article Synopsis
  • * The combination of PMTAC and sacran results in a structured hybrid film that significantly lowers friction in salt-free environments and transitions the lubrication mode to a more efficient hydrodynamic lubrication.
  • * However, adding salt (NaCl) to the solution disrupts the electrostatic assembly of the materials, diminishing their lubrication effectiveness.
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Article Synopsis
  • * The resulting copolymers have varying molecular weights and structures that impact their mechanical properties and glass transition temperatures, which can be tailored for various uses.
  • * Notably, these materials can autonomously self-heal from damage in multiple environments and demonstrate impressive elastic properties, while also showcasing shape-memory capabilities depending on their composition.
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The ion-specific hydration states of zwitterionic poly(3-( N-2-methacryloyloxyethyl- N, N-dimethyl)ammonatopropanesulfonate) (PMAPS) brushes in various aqueous solutions were investigated by neutron reflectivity (NR) and atomic force microscopy (AFM). The asymmetric hydration state of the PMAPS brushes was verified from the NR scattering-length density profiles, while the variation in their swollen thickness was complementary as determined from AFM topographic images. PMAPS brushes got thicker in any salt solutions, while the extent of swelling and the dimensions of swollen chain structure were dependent on the ion species and salt concentration in the solutions.

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Phosphorylated cellulose nanocrystal (P-CNC)/imogolite nanotube (natural aluminosilicate nanotube) hybrid thin films were fabricated by spin-assisted layer-by-layer assembly. Phosphorylation of CNC with diammonium hydrogen phosphate ((NH)HPO) was carried out to introduce phosphate groups on the CNC surface for enhanced interaction with imogolite. Structure of the P-CNC/imogolite thin film was characterized by atomic force microscopy, scanning electron microscopy, X-ray diffraction (XRD), and grazing incidence wide-angle XRD.

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Article Synopsis
  • * The text discusses recent advancements in modifying HNT’s surface and creating functional organic-inorganic nanohybrids.
  • * Examples of these advancements include hybrid nanocontainers, flame retardant nanocomposites, dye removal adsorbents, liquid marbles, and superamphiphobic coatings.
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The morphology of spin-coated films and electrospun fibers of ethyl hydroxy ethyl cellulose (EHEC), hydrophobically modified ethyl hydroxy ethyl cellulose (HM-EHEC) and their blends with Poly(vinyl alcohol) (PVA) was examined by AFM, SEM and contact angle measurements. These polysaccharides upon blending with PVA exhibited smooth surface which was evidenced by Atomic Force Microscopy (AFM) observation. The electrospinnability of above polysaccharides with PVA was demonstrated for the first time.

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Effect of alkyl chain spacer length between the charged groups (CSL) in zwitterionic poly(sulfobetaine) (PSB) brushes on the hydration state was investigated. PSB brushes with ethyl (PMAES), propyl (PMAPS), or butyl (PMABS) CSL were prepared by surface-initiated atom transfer radical polymerization on silicon wafers. Hydration states of the PSB brushes in aqueous solutions and/or humid vapor were investigated by contact angle measurement, infrared spectroscopy, AFM observation, and neutron reflectivity.

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The orientation and crystallization of regioregular poly(3-dodecylthiophene) (P3DDT) in different diameter nanopores were investigated. P3DDT nanowires were prepared by a melt-wetting nonporous alumina template with P3DDT melts. The microstructure of the nanowires was analyzed by micro-Fourier transform infrared spectroscopy, grazing incidence wide angle X-ray diffraction, and differential scanning calorimetry.

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Water existing in the vicinity of polyelectrolytes exhibits unique structural properties, which demonstrate key roles in chemistry, biology, and geoscience. In this study, X-ray absorption and emission spectroscopy was employed to observe the local hydrogen-bonding structure of water confined in a charged polyelectrolyte brush. Even at room temperature, a majority of the water molecules confined in the polyelectrolyte brush exhibited one type of hydrogen-bonding configuration: a slightly distorted, albeit ordered, configuration.

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Zwitterionic polymer brushes draw increasing attention not only because of their superhydrophilic, self-cleaning capability but also due to their excellent antifouling capacity. We investigated the ion-specific modulation of the interfacial interaction potential via densely packed, uniform poly(sulfobetaine) brushes. The vertical Brownian motion of a cell-sized latex particle was monitored by microinterferometry, yielding the effective interfacial interaction potentials V(Δh) and the autocorrelation function of height fluctuation.

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