Publications by authors named "Shin Ichi Adachi"

This work investigates and describes the structural dynamics taking place following charge-transfer-to-solvent photo-abstraction of electrons from I and Br ions in aqueous solution following single- and 2-photon excitation at 202 nm and 400 nm, respectively. A Time-Resolved X-ray Solution Scattering (TR-XSS) approach with direct sensitivity to the structure of the surrounding solvent as the water molecules adopt a new equilibrium configuration following the electron-abstraction process is utilized to investigate the structural dynamics of solvent shell expansion and restructuring in real-time. The structural sensitivity of the scattering data enables a quantitative evaluation of competing models for the interaction between the nascent neutral species and surrounding water molecules.

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Topological insulators (TI) hold significant potential for various electronic and optoelectronic devices that rely on the Dirac surface state (DSS), including spintronic and thermoelectric devices, as well as terahertz detectors. The behavior of electrons within the DSS plays a pivotal role in the performance of such devices. It is expected that DSS appear on a surface of three dimensional(3D) TI by mechanical exfoliation.

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Diabetes is caused by abnormal glucose metabolism, and muscle, the largest tissue in the human body, is largely involved. Urolithin A (UroA) is a major intestinal and microbial metabolite of ellagic acid and ellagitannins and is found in fruits such as strawberry and pomegranate. In this present study, we investigated the antidiabetic effects of UroA in L6 myotubes and in KK-A/Ta, a mouse model of type 2 diabetes (T2D).

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Stacked teacups inspired the idea that columnar assemblies of stacked bowl-shaped molecules may exhibit a unique dynamic behavior, unlike usual assemblies of planar disc- and rod-shaped molecules. On the basis of the molecular design concept for creating higher-order discotic liquid crystals, found in our group, we synthesized a sumanene derivative with octyloxycarbonyl side chains. This molecule forms an ordered hexagonal columnar mesophase, but unexpectedly, the columnar assembly is very soft, similar to sugar syrup.

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Time-resolved X-ray liquidography (TRXL) has emerged as a powerful technique for studying the structural dynamics of small molecules and macromolecules in liquid solutions. However, TRXL has limited sensitivity for small molecules containing light atoms only, whose signal has lower contrast compared with the signal from solvent molecules. Here, we present an alternative approach to bypass this limitation by detecting the change in solvent temperature resulting from a photoinduced reaction.

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Operando time-resolved soft x-ray absorption spectroscopy (TR-SXAS) is an effective method to reveal the photochemical processes of metal complexes in solutions. In this study, we have developed the TR-SXAS measurement system for observing various photochemical reactions in solutions by the combination of laser pump pulses with soft x-ray probe pulses from the synchrotron radiation. For the evaluation of the developed TR-SXAS system, we have measured nitrogen K-edge x-ray absorption spectroscopy (XAS) spectra of aqueous iron phenanthroline solutions during a photoinduced spin transition process.

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Photochemical reactions in solution are governed by a complex interplay between transient intramolecular electronic and nuclear structural changes and accompanying solvent rearrangements. State-of-the-art time-resolved X-ray solution scattering has emerged in the last decade as a powerful technique to observe solute and solvent motions in real time. However, disentangling solute and solvent dynamics and how they mutually influence each other remains challenging.

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This paper presents a trial analysis of the relationship between taste and biological information obtained while eating strawberries (for a sensory evaluation). This study used the visual analog scale (VAS); we collected questionnaires used in previous studies and human brain activity obtained while eating strawberries. In our analysis, we assumed that brain activity is highly correlated with taste.

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Article Synopsis
  • - A new measurement system for picosecond pump-probe resonant soft X-ray scattering has been developed at the Photon Factory to enhance data collection efficiency.
  • - A high-repetition-rate and high-power compact laser system is now in place, allowing for flexible data acquisition at sub-MHz frequencies for time-resolved experiments.
  • - The system successfully captures the photoinduced dynamics of magnetic order in multiferroic manganite SmMnO, showing changes in resonant soft X-ray scattering around the Mn L- and O K-edges.
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The alignment control of discotic columnar liquid crystals (LCs), featuring a low motility of the constituent molecules and thus having a large viscosity, is a challenging task. Here we show that triphenylene hexacarboxylic ester, when functionalized with hybrid side chains consisting of alkyl and perfluoroalkyl groups in an appropriate ratio, gives a hexagonal columnar (Col) LC capable of selectively forming large-area uniform homeotropic or homogeneous alignments, upon cooling from its isotropic melt or upon application of a shear force at its LC temperature, respectively. In addition to the alignment switching ability, each alignment state remains persistent unless the LC is heated to its melting temperature.

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In photosynthetic systems employing multiple transition metal centers, the properties of charge-transfer states are tuned by the coupling between metal centers. Here, we use ultrafast optical and X-ray spectroscopies to elucidate the effects of metal-metal interactions in a bimetallic tetrapyridophenazine-bridged Os(ii)/Cu(i) complex. Despite having an appropriate driving force for Os-to-Cu hole transfer in the Os(ii) moiety excited state, no such charge transfer was observed.

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The understanding of O-O bond formation is of great importance for revealing the mechanism of water oxidation in photosynthesis and for developing efficient catalysts for water oxidation in artificial photosynthesis. The chemical oxidation of the Ru(OH)(OH) core with the vicinal OH and OH ligands was spectroscopically and theoretically investigated to provide a mechanistic insight into the O-O bond formation in the core. We demonstrate O-O bond formation at the low-valent Ru(OH) core with the vicinal OH ligands to form the Ru(μ-OOH) core with a μ-OOH bridge.

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Muscle is the largest tissue in our body and plays an important role in glucose homeostasis and hence diabetes. In the present study, we examined the effects of taxifolin (TXF) on glucose metabolism in cultured L6 muscle cells (myotubes) and in type 2 diabetic (T2D) model KK-A/Ta mice. TXF dose-dependently increased glucose uptake (GU) in L6 myotubes under the condition of insulin absence.

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The halogen elimination of 1,2-diiodoethane (CHI) and 1,2-diiodotetrafluoroethane (CFI) serves as a model reaction for investigating the influence of fluorination on reaction dynamics and solute-solvent interactions in solution-phase reactions. While the kinetics and reaction pathways of the halogen elimination reaction of CHI were reported to vary substantially depending on the solvent, the solvent effects on the photodissociation of CFI remain to be explored, as its reaction dynamics have only been studied in methanol. Here, to investigate the solvent dependence, we conducted a time-resolved X-ray liquidography (TRXL) experiment on CFI in cyclohexane.

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Recent evidence demonstrated that chronic intake of quercetin attenuated hepatic fat accumulation in various animal models of obesity and diabetes. However, whether quercetin has the ability to enhance energy metabolism in hepatocytes and its exact mechanisms have yet to be identified. In the present study, we investigated whether quercetin directly enhanced the energy metabolism of cultured hepatocytes by focusing on lipophagy, involving selective autophagic degradation of lipid droplets.

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Article Synopsis
  • Extensive studies on haloalkanes have not fully clarified the molecular structure of precursors to isomers formed during photodissociation, particularly regarding the in-cage isomerization process.
  • Researchers used femtosecond X-ray solution scattering to analyze the structural dynamics of CHI when exposed to 267 nm light in methanol.
  • The results revealed a transient species with an I-I distance of 4.17 Å and unusual structural properties that suggest it could be a vibrationally hot isomer or a loosely-bound radical pair.
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Hyperuricemia, the high uric acid (UA) state in blood, has been accepted as an important risk factor for gout. The liver is a main factory of UA production. In the present study, we have examined the effects of three kinds of flavonol and flavones as typical aglycons, i.

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Article Synopsis
  • The study investigates the photophysical properties of two rhenium(I) diimine complexes in acetonitrile, focusing on how their structural differences impact their behavior upon photoexcitation.
  • The complexes differ in the number of phenyl groups in their phosphine ligands, resulting in significant variations in emission wavelength and excited-state lifetime, despite the minor structural change.
  • Key findings include alterations in bond lengths and angles during excitation, with complex (3,3) displaying more significant structural changes and a longer excited-state lifetime due to steric effects from the phenyl groups.
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Ultrafast, light-induced dynamics in copper-zinc-tin-sulfide (CZTS) photovoltaic nanoparticles are investigated through a combination of optical and x-ray transient absorption spectroscopy. Laser-pump, x-ray-probe spectroscopy on a colloidal CZTS nanoparticle ink yields element-specificity, which reveals a rapid photo-induced shift of electron density away from Cu-sites, affecting the molecular orbital occupation and structure of CZTS. We observe the formation of a stable charge-separated and thermally excited structure, which persists for nanoseconds and involves an increased charge density at the Zn sites.

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Interleukin 15 receptor (IL-15R) is a transmembrane signalling protein consisting of 3 subsets: α, β (IL-15Rβ), and γ (γ). IL-2 and IL-15 share the signalling domains IL-15Rβ and γ, although they bind to intrinsic α-subsets and non-signalling domains. Additionally, IL-2 and IL-15 play different roles; therefore, there have been many observations of the dynamic behaviours of IL-15R, which are linked to physiological functions.

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Helical folding of randomly coiled linear polymers is an essential organization process not only for biological polypeptides but also for synthetic functional polymers. Realization of this dynamic process in supramolecular polymers (SPs) is, however, a formidable challenge because of their inherent lability of main chains upon changing an external environment that can drive the folding process (e.g.

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Hyperuricemia is defined as a disease with high uric acid (UA) levels in the blood and a strong risk factor for gout. Urolithin A (UroA) is a main microbial metabolite derived from ellagic acid (EA), which occurs in strawberries and pomegranates. In this study, we evaluated antihyperuricemic effect of UroA in both cultured hepatocytes and hyperuricemic model mice.

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G protein-coupled receptors (GPCRs) are seven-transmembrane proteins, which transmit extracellular signals inside cells via activating G proteins. GPCRs are involved in a wide variety of physiological functions, such as signal sensing, immune system processes, and neurotransmission. Although the structures and functions of GPCRs have been well studied, little has been known about their real-time dynamics on live cells.

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