Soft x-ray high diffraction efficiency and spectral flux laminar-type W/B4C multilayer diffraction grating for 300-1000 eV.

Multilayer diffraction gratings are designed to improve the detection limit and sensitivity of soft x-ray flat-field spectrographs in the region of 300-1000 eV, placing emphasis on Fe-L (705 eV), Cu-L (930 eV), and Zn-L (1012 eV) emissions. For this purpose, spectral flux was used as the performance index, which is proportional to the amount of optical flux incident into a detector and correlated with detection sensitivity. A super-mirror-type W/B4C multilayer coating [Koike et al., Rev.Sci. Instrum. 94, 045109 (2023)] was employed to improve diffraction efficiency in a wide energy region. The unique feature of the multilayer structure is that the average refractive index and the period length of W/B4C layer pairs are increased from the bottom to top layers. In addition, the incidence angle was reduced to 86.03° from 88.65° and the nominal groove density was increased to 3200 lines/mm from 2400 lines/mm of our previous design, to improve spectral flux while maintaining dispersion and spectral resolution. A holographic varied-line-spacing spherical grating and a soft x-ray flat-field spectrograph were designed, using the aspherical-wavefront-recording method, assuming the nominal grating constant and incident angle described above. The numerical simulation results showed that the spectrograph employing the newly designed grating with the W/B4C multilayer indicated 3.2-8.2 times higher spectral flux compared with those using the previously designed grating while keeping the same spectral resolution.

Association of Finger Tapping Movements with Frailty Status in older Japanese Adults: A Cross-Sectional Study.

BACKGROUND: Finger tapping impairment and frailty share overlapping pathophysiology and symptoms in older adults, however, the relationship between each other has not been previously studied. OBJECTIVES: To investigate how finger tapping movements correlate with frail status in older Japanese adults. DESIGN, SETTING, AND PARTICIPANTS: Data were from a cross-sectional study called the Cognition and Activity in Rural Environment of Hokkaido Senior Survey 2018. A total of 244 community-dwelling older adults (mean age 75.3 years) were included. MEASUREMENTS: Participants underwent physical examinations, gait and finger tapping tests, and completed self-administered questionnaires. Frailty was assessed using Fried's frailty phenotype, and factor analysis was conducted to extract relevant finger tapping factors. Multinomial logistic regression was employed to analyze associations, generating adjusted odds ratios. RESULTS: Of the participants, 18 were frail, and 145 pre-frail. Analysis identified three distinct finger tapping patterns: "Range of Motion - Nondominant Hand," "Variability - Dominant Hand - Anti," and "Variability - Nondominant Hand - Anti." These patterns showed significant associations with aspects of Fried's frailty phenotype, particularly low physical activity (P = 0.002), weakness (P = 0.003), and slowness (P = 0.004). A larger range of motion in the nondominant hand correlated with a lower frailty risk (Odds Ratio: 0.09, 95% CI: 0.02-0.46), while higher variability in the same hand increased the risk of pre-frailty (Odds Ratio: 2.19, 95% CI: 1.09-4.39). CONCLUSION: Finger tapping movements are significantly associated with frailty status as determined by Fried's phenotype. The findings underscore the importance of further longitudinal studies to understand the relationship between motor function and frailty.

Regional Inequalities in Oral Frailty and Social Capital.

INTRODUCTION: Oral frailty leads to poor nutritional status, which, in turn, leads to frailty. This cross-sectional study aimed to determine regional differences in the prevalence of oral frailty and to identify factors associated with oral frailty using 3-level multilevel models. METHODS: This study comprised 165,164 participants aged ≥65 y without long-term care requirements in the Japan Gerontological Evaluation Study. The dependent variable was oral frailty, which was calculated based on age, number of teeth, difficulty in eating tough foods, and choking. The individual-level independent variables included sociodemographics, present illness, social participation, frequency of meeting friends, and social capital. The local district-level independent variable was social capital (n = 1,008) derived from exploratory factor analyses. The municipality-level independent variable was population density (n = 62). Three-level multilevel Poisson regression analysis was performed to calculate the prevalence ratios (PRs). RESULTS: The prevalence of oral frailty in municipalities ranged from 39.9% to 77.6%. Regarding district-level factors, higher civic participation was significantly associated with a lower probability of oral frailty. At the municipality level, the PR of the rural-agricultural area was 1.17 (95% confidence interval, 1.11-1.23) (reference: metropolitan). CONCLUSION: These results highlight the usefulness of oral frailty prevention measures in encouraging social participation in rural areas. KNOWLEDGE TRANSFER STATEMENT: The results of the present study showed regional differences in oral frailty. In particular, rural-agricultural areas show higher prevalence rates of oral frailty than those in metropolitan cities. Promoting measures of social participation among older adults may help prevent oral frailty in rural areas.

Heterogeneous Association of Tooth Loss with Functional Limitations.

Tooth loss is prevalent in older adults and associated with functional capacity decline. Studies on the susceptibility of some individuals to the effects of tooth loss are lacking. This study aimed to investigate the heterogeneity of the association between tooth loss and higher-level functional capacity in older Japanese individuals employing a machine learning approach. This is a prospective cohort study using the data of adults aged ≥65 y in Japan (N = 16,553). Higher-level functional capacity, comprising instrumental independence, intellectual activity, and social role, was evaluated using the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC). The scale ranged from 0 (lowest function) to 13 (highest function). Doubly robust targeted maximum likelihood estimation was used to estimate the population-average association between tooth loss (having <20 natural teeth) and TMIG-IC total score after 6 y. The heterogeneity of the association was evaluated by estimating conditional average treatment effects (CATEs) using the causal forest algorithm. The result showed that tooth loss was statistically significantly associated with lower TMIG-IC total scores (population-average effect: -0.14; 95% confidence interval, -0.18 to -0.09). The causal forest analysis revealed the heterogeneous associations between tooth loss and lower TMIG-IC total score after 6 y (median of estimated CATEs = -0.13; interquartile range = 0.12). The high-impact subgroup (i.e., individuals with estimated CATEs of the bottom 10%) were significantly more likely to be older and male, had a lower socioeconomic status, did not have a partner, and had poor health conditions compared with the low-impact subgroup (i.e., individuals with estimated CATEs of the top 10%). This study found that heterogeneity exists in the association between tooth loss and lower scores on functional capacity. Implementing tooth loss prevention policy and clinical measures, especially among vulnerable subpopulations significantly affected by tooth loss, may reduce its burden more effectively.

Laminar-type gratings overcoated with carbon-based materials to enhance analytical sensitivity of flat-field emission spectrograph in the VUV region.

Laminar-type spherical diffraction gratings overcoated with carbon-based materials were designed, fabricated, and evaluated for the purpose of enhancing the analytical sensitivity of the flat-field spectrograph in a vacuum ultraviolet region of 35-110 eV. As the design benchmark for numerical calculations, diffraction efficiency (DE) and spectral flux, which are defined by the product of the DE and numerical aperture and correlate with the analytical sensitivity of the spectrograph, were used. To simplify the feasibility study on the overcoating effects, we assumed a laminar-type grating having a grating constant of 1/1000 mm and coated with a Au layer of 30.0 nm thickness and an incidence angle of 84.0°. The optimized groove depth and duty ratio were 30.0 nm and 0.3, respectively. In addition, the optimum thicknesses of the overcoating layer were 44, 46, 24, and 30 nm for B4C, C, diamond-like-carbon, and SiC, respectively. Based on these results, we have fabricated a varied-line-spacing holographic grating overcoated with B4C with a thickness of 47 nm. For the experimental evaluation, we used the light source of Mg-L and Al-L emissions excited by the electron beam generated from an electron microscope, an objective flat-field spectrograph, and a CCD imaging detector. The experimental results showed that the spectrograph employing a new grating overcoated with the B4C layer indicated almost the same spectral resolution and 2.9-4.2 times higher analytical sensitivity compared with those obtained with a previously designed Au-coated grating having a grating constant of 1/1200 mm and used at an incidence of 86.0°.