Publications by authors named "Shin-Ichiro Sato"

Low-concentration alkali treatments at low temperatures facilitate the crystal transition of cellulose I to II. However, the transition mechanism remains unclear. Hence, in this study, we traced the transition using in situ solid-state C CP/MAS NMR, WAXS, and Na NMR relaxation measurements.

View Article and Find Full Text PDF

The group-transfer polymerization (GTP) of ,-bis(2-methoxyethyl)acrylamide (MOEAm) initiated by MeEtSiH in the hydrosilylation-promoted method and by silylketene acetal (SKA) in the conventional method proceeded in a controlled/living manner to provide poly(,-bis(2-methoxyethyl)acrylamide) (PMOEAm) and PMOEAm with the SKA residue at the α-chain end (MCIP-PMOEAm), respectively. PMOEAm--poly(dimethylacrylamide) (PDMAm) and PMOEAm--PDMAm and PMOEAm--poly(-bis(2-ethoxyethyl)acrylamide) (PEOEAm) and PMOEAm--PEOEAm were synthesized by the block and random group-transfer copolymerization of MOEAm and dimethylacrylamide or -bis(2-ethoxyethyl)acrylamide. The homo- and copolymer structures affected the thermoresponsive properties; the cloud point temperature () increasing by decreasing the degree of polymerization (x).

View Article and Find Full Text PDF
Article Synopsis
  • The study focuses on the redox behaviors of macrocyclic molecules, particularly cyclic P3HT, and how their unique structure impacts their optical, electronic, and magnetic properties.
  • It was observed that cyclic P3HT is more stable during electrochemical tests compared to linear P3HT, with its HOMO level decreasing as the degree of polymerization increases.
  • The findings indicate that cyclic P3HT exhibits stronger dicationic properties due to polarons interacting closely, while linear P3HT displays characteristics of polaron pairs and multiple isolated polarons.
View Article and Find Full Text PDF
Article Synopsis
  • Lanthanoid-doped Gallium Nitride (GaN) nanopillars are being explored as effective room-temperature quantum photon sources for quantum technology.
  • We created praseodymium (Pr)-doped GaN nanopillars of different sizes, achieving a 23.5 times increase in photon extraction efficiency compared to non-structured versions.
  • The study identifies two key emission peaks from Pr ions and explains how the design of the nanopillars enhances photon collection through eigenmode resonance, paving the way for advanced photon emitters in quantum tech.
View Article and Find Full Text PDF

Silver nanoparticles (AgNPs) are used in a wide range of applications, and the size control and stability of the nanoparticles are crucial aspects in their applications. In the present study, cyclized poly(ethylene glycol) (-PEG) with various molecular weights, along with linear PEG with hydroxy chain ends (HO-PEG-OH) and methoxy chain ends (MeO-PEG-OMe) were applied for the Tollens' synthesis of AgNPs. The particle size was significantly affected by the topology and end groups of PEG.

View Article and Find Full Text PDF

Silver nanoparticles (AgNPs) are practically valuable in biological applications. However, no steady PEGylation has been established, which is essential for internal use in humans or animals. In this study, cyclic PEG (-PEG) without any chemical inhomogeneity is physisorbed onto AgNPs to successfully PEGylate and drastically enhance the dispersion stability against physiological conditions, white light, and high temperature.

View Article and Find Full Text PDF

Snare devices play an important role in treatment of intestinal polyps. However, there are no objective measurements for the characteristics of the various types of snare devices. Seven types of snare devices from four manufacturers were evaluated based on original measurements.

View Article and Find Full Text PDF
Article Synopsis
  • - The study examined how the cyclization of amphiphilic Pluronic copolymers impacts their thermal phase transition, focusing on different block sequences (hydrophilic-hydrophobic-hydrophilic and hydrophobic-hydrophilic-hydrophobic).
  • - Results showed that cyclization leads to lower critical micelle temperatures, reduced micellization enthalpy, and entropy, highlighting differences based on the copolymer's block sequence.
  • - Comparing linear and cyclized forms revealed that the effects of cyclization can't be simply attributed to the removal of terminal hydrophilic elements, indicating more complex interactions at play.
View Article and Find Full Text PDF
Article Synopsis
  • - A study discovered that cyclic poly(ethylene glycol) (-PEG) interacts significantly with bovine serum albumin (BSA), unlike its linear counterparts, which show no affinity.
  • - The research noted that when gold nanoparticles were combined with -PEG (AuNPs/-PEG), they formed aggregates with BSA, causing the dispersion's red color to fade, a reaction not seen with linear PEG or no PEG.
  • - The interactions between BSA, AuNPs, and PEG were analyzed through various methods, including UV-Vis and fluorescence spectroscopy, by adjusting incubation times and concentrations of the components.
View Article and Find Full Text PDF
Article Synopsis
  • - The study investigates the thermoresponsive properties of various copolymers made from poly(glycidol)s (PG) and poly(ethyl glycidyl ether) (PEGE), synthesized using different methods, particularly ring-opening polymerization (ROP) with specific catalysts.
  • - A comparison of different copolymer structures, including statistical, diblock, triblock, and pentablock configurations, reveals that certain compositions exhibit LCST-type phase transitions in water, influenced by their arrangement and the specific ratios of the components.
  • - Findings indicate that the disorder within the copolymer significantly impacts phase-transition behavior, resulting in complex two-stage phase transitions, where initial LCST-type transitions are followed by UCST-like transitions in
View Article and Find Full Text PDF

A series of cyclic surfactants were synthesized from a poly(ethylene glycol) (PEG) homopolymer and Pluronic surfactants L35, L64, P123, F68, 10R5, and 17R4, and their interfacial activity depending on the topology, chain ends, and block sequence was investigated. The cyclization was performed in a single step through etherification of the PEG homopolymer and the hydrophilic-hydrophobic-hydrophilic (ABA type) poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEG-PPG-PEG), while the hydrophobic-hydrophilic-hydrophobic (BAB type) PPG-PEG-PPG was cyclized via acetalization. The cyclized surfactants were rigorously characterized by nuclear magnetic resonance spectroscopy and size exclusion chromatography.

View Article and Find Full Text PDF
Article Synopsis
  • - The study explores how biomolecular systems control their local environments at a very small scale, focusing on oligo(ethylene glycol) (OEG) derivatives on gold nanoparticles and how this affects their flexibility and functions.
  • - Researchers demonstrate that the thermo-responsive properties of these OEG-attached gold nanoparticles can be manipulated through changes in hydrophobicity and nanoparticle surface curvature, leading to assembly and disassembly in water based on temperature.
  • - Molecular dynamics simulations reveal that the arrangement of hydrophobic ends along the gold surface changes with surface curvature, suggesting that a bent molecular shape can enhance thermo-responsiveness, which is influenced by adjustments in OEG density and mixing with different OEG lengths.
View Article and Find Full Text PDF

Ultrathin endoscopes are commonly used for surveillance esophagogastroduodenoscopy (EGD) to reduce discomfort associated with scope insertion. However, the flexibility of an ultrathin endoscope is a trade-off between reducing discomfort and lengthening examination time.  The EG17-J10 (EG17) is a novel ultrathin endoscope characterized by its tapering body stiffness; however, the flexibility of its tip is comparable to that of the traditional ultrathin endoscope EG16-K10 (EG16).

View Article and Find Full Text PDF
Article Synopsis
  • Nano-sized metal particles, especially gold nanoparticles (AuNPs), are gaining attention for their potential in industrial and biomedical fields due to advancements in nanotechnology.
  • Researchers used cyclic poly(ethylene glycol) (c-PEG) for surface modification of AuNPs, providing better dispersion stability compared to linear PEG versions and even thiolated PEG.
  • The study showed that c-PEG not only improves the stability of AuNPs but also enhances their circulation in the bloodstream and accumulation in tumors when tested in mice, suggesting its effectiveness for biomedical applications.
View Article and Find Full Text PDF

Single-photon sources and their optical spin readout are at the core of applications in quantum communication, quantum computation, and quantum sensing. Their integration in photonic structures such as photonic crystals, microdisks, microring resonators, and nanopillars is essential for their deployment in quantum technologies. While there are currently only two material platforms (diamond and silicon carbide) with proven single-photon emission from the visible to infrared, a quantum spin-photon interface, and ancilla qubits, it is expected that other material platforms could emerge with similar characteristics in the near future.

View Article and Find Full Text PDF

A quinoline-based hexadentate ligand, (,)-,,,-tetrakis(6-methoxy-2-quinolylmethyl)-1,2-diphenylethylenediamine ((,)-6-MeOTQPhEN), exhibits fluorescence enhancement at 498 nm upon addition of 1 equiv of Zn (/ = 12, φ = 0.047) in aqueous DMF solution (DMF/HO = 2:1). Addition of 1 equiv of Cd affords a much smaller fluorescence increase at the same wavelength (/ = 2.

View Article and Find Full Text PDF

A 54-year-old man with diarrhea and hematochezia for 2 months was referred to our department. A total colonoscopy revealed amoebic colitis caused by Entamoeba histolytica. Concurrently, a submucosal tumor-like yellowish hemispheric polypoid lesion was incidentally detected in the rectum.

View Article and Find Full Text PDF

We report the enhancement of the optical emission between 850 and 1400 nm of an ensemble of silicon mono-vacancies (V), silicon and carbon divacancies (VV), and nitrogen vacancies (NV) in an n-type 4H-SiC array of micropillars. The micropillars have a length of ca. 4.

View Article and Find Full Text PDF

EGTA (ethylene glycol bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid) and BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) are well-known Ca2+ chelators that have four carboxylates, two nitrogen atoms and two ether oxygen atoms. In the present study, we prepared EGTQ (N,N,N',N'-tetrakis(2-quinolylmethyl)-1,2-bis(2-aminoethoxy)ethane) and BAPTQ (N,N,N',N'-tetrakis(2-quinolylmethyl)-1,2-bis(2-aminophenoxy)ethane) as quinoline alternatives of EGTA and BAPTA, respectively. In methanol-HEPES buffer solution (9 : 1, 50 mM HEPES, 0.

View Article and Find Full Text PDF

We characterized intrinsic deep level defects created in ion collision cascades which were produced by patterned implantation of single accelerated 2.0 MeV He and 600 keV H ions into n-type 4H-SiC epitaxial layers using a fast-scanning reduced-rate ion microbeam. The initial deep level transient spectroscopy measurement performed on as-grown material in the temperature range 150-700 K revealed the presence of only two electron traps, Z (0.

View Article and Find Full Text PDF

A quinoline-based heptadentate ligand, N,N,N',N'-tetrakis(2-quinolylmethyl)-3-oxa-1,5-pentanediamine (TQOPEN), exhibits a fluorescence increase (I/I = 25, ϕ = 0.017) at 428 nm upon addition of 1 equiv of Cd. In contrast, 1 equiv of Zn induces a negligible fluorescence change due to weak interaction (I/I = 2.

View Article and Find Full Text PDF

An isoquinoline-based ligand, N,N,N',N'-tetrakis(1-isoquinolylmethyl)-2-hydroxy-1,3-propanediamine (1-isoHTQHPN), exhibits a fluorescence increase at 475 nm upon addition of 1 equiv. of Zn(2+) (IZn/I0 = 12, ϕZn = 0.023).

View Article and Find Full Text PDF