Industrial Technology Center of Okayama Prefecture

This study investigates the effects of Ar+ sputtering on an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6) with the use of x-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR). XPS analysis showed spectral changes in the C 1s and O 1s peaks, with surface contaminants nearly disappearing after Ar+ sputtering. Complementary 1H NMR spectroscopy indicated no bulk structural modification. These results suggest that impurities undergo preferential removal during sputtering by both desorption into the vacuum and segregation of nonvolatile species into the bulk, behavior that reflects the inherent fluidity of ionic liquids. This behavior differs from that of solid samples, where impurities are more restricted in mobility. This study contributes to the methodology for surface characterization of ionic liquids under vacuum conditions, with implications for research in materials science and electrochemistry.

A sustainable method for efficiently producing and depositing silver nanoparticles (AgNPs) onto cellulose nanofibers (CNFs) was developed in this study by harnessing high-pressure wet-type jet milling-induced redox reactions.An aqueous solution of silver nitrate was mixed with a CNF suspension and subsequently subjected to 0-4 jet-milling passes at a discharge pressure of 200 MPa.Additionally, the influence of the pipe fitting material on the formation of nanoparticles (NPs) was evaluated by using either 304 stainless steel (SUS304) or brass pipe fittings between the feed tank and the collision chamber.The X-ray diffraction pattern of the sample prepared using brass fittings and subjected to one jet-milling pass exhibited distinct peaks corresponding to metallic silver, confirming the presence of AgNPs, in addition to those from cellulose crystallites.In contrast, the sample prepared using SUS304 fittings exhibited only peaks corresponding to cellulose crystallites, with no detectable peaks attributable to metallic silver.Transmission electron microscopy revealed that the CNF surface of the sample processed with brass fittings were uniformly and densely covered with spherical AgNPs (diameters <5 nm), and that the particle size distribution was remarkably narrow.In contrast, the quantity of NPs prepared using SUS304 fittings was insufficient to achieve uniform coverage, with deposition confined to isolated regions on the CNF surface.Furthermore, the larger amount of AgNPs deposited with the brass fittings, as compared to the SUS304 fittings, proportionally increased with the number of jet-milling passes.This enhanced deposition is attributed to the presence of copper and zinc in the brass fittings, which likely promote the redox reaction-induced reduction of silver ions.By synergistically coupling the intense cavitation generated during high-pressure wet jet milling with redox activity derived from brass fittings, the reduction of Ag(I) to Ag(0) was markedly enhanced, enabling dense and uniform deposition of AgNPs on the CNF surface.

Study objectivesNonrestorative sleep (NRS) has been identified as a potential risk factor for physical and mental well-being in adults, but limited research exists for children and adolescents. This study aimed to clarify the factors associated with NRS in Japanese junior high school students.MethodsThe participants were 529 Japanese junior high school students in grades 7 through 9. Participants were asked to respond to Google Forms, and responses were obtained from 392 students. Sleep habits, history of coronavirus disease (COVID-19), physical symptoms, social isolation, and the presence of the symptoms of restless legs syndrome (RLS) were identified. NRS, insomnia symptoms, and depressive symptoms were evaluated using the Restorative Sleep Questionnaire (RSQ), Athens Insomnia Scale (AIS), and Patient Health Questionnaire (PHQ)-9, respectively. The cut-off value for NRS determination by the RSQ score was the mean of the scores that maximized the sensitivity and specificity sum for detecting participants with AIS and PHQ-9 scores of ≥ 6 and ≥ 5, respectively. NRS-associated sleep parameters and those associated with depressive symptoms were evaluated using binominal logistic regression analysis. Multinomial logistic regression (MLR) analysis was used to confirm the reproducibility of the binomial logistic regression analysis results with lower RSQ scores.ResultsThe NRS group comprised 40.1% of participants and exhibited a higher prevalence of physical and depressive symptoms compared to those with restorative sleep. Logistic regression analysis, adjusted for sex, grade, and COVID-19 history, revealed the following odds ratios (95% confidence interval) for NRS: average total sleep time < 7 h 2.44 (1.16–4.33), AIS ≥ 6 2.74 (1.51–4.95), evening chronotype 2.58 (1.49–4.47), and RLS symptoms 2.21 (1.21–4.03). The same results were obtained using MLR as those obtained via binomial logistic regression analysis. Logistic regression analysis for depressive symptoms revealed that NRS displayed the highest odds ratio (95% CI) of 3.16 (1.90–5.27) among the sleep-related variables.ConclusionsThese findings suggest that NRS in Japanese junior high school students is associated with physical and mental health issues. Intervention and longitudinal studies are warranted to address NRS-associated sleep–wake problems in this age group.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40101-025-00412-8.

Sake brewed using the kimoto-style exhibits high antioxidant capacity and is expected to inhibit the deterioration of sake quality due to oxidation. However, the antioxidant capacity of the added lactic acid bacteria has not been explored. We aimed to screen the lactic acid bacterium, Leuconostoc mesenteroides, with excellent brewing and antioxidant capacity, to develop sake with high antioxidant capacity. Three Le. mesenteroides strains (19-2, 19-5, and 19-23) were selected from eight screened strains based on their alcohol intolerance, growth performance in koji extract, aroma compound, and low biogenic amine production. Among these, Le. mesenteroides 19-23 exhibited a significantly higher hydrophilic-oxygen radical absorbance capacity (H-ORAC) in the culture medium than the control strain, Le. mesenteroides NBRC102481. In a medium-scale sake brewing test, sake prepared with Le. mesenteroides 19-23 had a significantly higher H-ORAC value than that prepared using the sokujo-style (without Le. mesenteroides). Additionally, metabolome analysis using capillary electrophoresis time-of-flight mass spectrometry identified ferulic acid, p-coumaric acid, 3-hydroxyanthranilic acid (3-HAA), and 6,8-thioctic acid in the main mash. High-performance liquid chromatography-based quantification revealed that antioxidants in the unrefined filtrates of the main mash prepared using the kimoto-style tended to be more abundant than in those prepared using the sokujo-style. Specifically, 3-HAA and ferulic acid were more concentrated in some unrefined filtrates of the kimoto-style than sokujo-style. In conclusion, the screened Le. mesenteroides strain demonstrated potential for brewing sake with high antioxidant capacity using the kimoto-style, offering a promising method for antioxidant-rich sake production.

Flexible electronic devices and technologies are developed using large-scale strategies and nanomaterial composites for human-technology design, human–computer interaction, biomedical and bioelectronics, soft robotics, sensing technologies, etc.

The preparation of particles composed of nanoporous silica (NS) and Mg 2+ -whitlockite (Mg-WH) would provide valuable insights for designing particles for biomedical applications.In this study, NS and Mg-WH composite particles were successfully synthesized.The addition of chitosan during synthesis possibly promoted the crystallization of calcium phosphate phases in the composite particles.Pore size distribution analysis of the particles showed a maximum at 3.2 nm.Investigating the adsorption of methylene blue onto the particles in a phosphate buffer (pH 7.4) showed that the saturated adsorption amount of methylene blue on the particles was significantly higher than that on commercial hydroxyapatite.The composite particles provided important results for potential applications as drug carriers for bone regeneration and repair.Key-words:

Abstract Landslides represent a significant geological hazard in Vietnam, affecting various regions and posing threats to human lives, property, and the environment. On October 12, 2017, a massive landslide struck Khanh Village, Hoa Binh Province, Vietnam, resulting in 18 fatalities and the destruction of five houses. The event highlighted the vulnerability of limestone regions in Vietnam to landslides, particularly during periods of heavy rainfall. This paper first provides preliminary survey results to examine the cause and mechanism of the landslide. The results show that heavy rain was triggering factor in the 2017 Khanh waterfall landslide. Using the LS-RAPID computational model, we reproduce the 2017 event and assess the risk of future landslides from the remaining steep slope of the Khanh waterfall area. The findings provide valuable data to assist authorities in enhancing landslide hazard assessment, as the remaining steep slope poses a significant risk of future landslide occurrence.

Dendrogeomorphology serves as a method to determine the timing of historical landslide events. This approach entails scrutinizing the spatial and temporal aspects of landslide occurrences by investigating their impact on tree growth by analyzing variations in tree-ring width, recovery timeline of injured tree stem, as well as the age of tree invasion and establishment in areas affected by landsliding. The method's advantage lies in its capacity to yield a large number of samples where trees are growing. This study encompasses research conducted in both the Sansukezawa landslide in Aomori Prefecture and the Kamitokitozawa landslide in Akita Prefecture, Japan. The examination includes an analysis of the reactions of a combined total of 187 tilted deciduous broadleaved trees and coniferous trees aged between 100 and 102 years in response to landslide events. The findings, revealed by variations in tree-ring width, suggested multiple landslide occurrences at the Sansukezawa landslide between 1901 and 2000. The magnitude of these events varied, encompassing localized activities such as the enlargement of landslide scarps to more extensive landslide movements. In the Kamitokitozawa landslide area, the development of impending landslide events, inferred from the recovery timeline of injured tree stems, included scarp expansion. There were five instances of landslide activities recorded during the period from 1999 to 2019.