Accurate evaluation of time-dependent background is essential for reliable neutron time-of-flight (TOF) transmission measurements in neutron resonance analysis (NRA). In this study, we experimentally investigated the time-dependent background in neutron transmission measurements utilizing a 6 Li-glass scintillation detector at the Kyoto University, Institute for Integrated Radiation and Nuclear Science - Linear Accelerator (KURNS-LINAC). A comparative analysis was conducted on three background evaluation techniques, namely the black resonance, neutron absorber, and pulse-height (PH) gate techniques under identical measurement conditions. The results demonstrated that background levels obtained with resonance filters or neutron absorbers can be underestimated due to gamma-ray attenuation by the inserted materials. Conversely, the PH gate technique can overestimate the background in the thermal energy range due to gamma-rays produced by the capture of scattered thermal neutrons. Herein, the characteristics, advantages, and limitations of each technique are discussed, and practical guidance for selecting appropriate techniques and corrections to achieve accurate background evaluation in neutron transmission measurements using a 6 Li-glass scintillation detector is presented, supporting improved resonance analysis for future NRA applications.
The relationship between self-reported falls and fracture risk was estimated in an international meta-analysis of individual-level data from 46 prospective cohorts. Previous falls were associated with an increased fracture risk in women and men and should be considered as an additional risk factor in the FRAX® algorithm. Previous falls are a well-documented risk factor for subsequent fracture but have not yet been incorporated into the FRAX algorithm. The aim of this study was to evaluate, in an international meta-analysis, the association between previous falls and subsequent fracture risk and its relation to sex, age, duration of follow-up, and bone mineral density (BMD). The resource comprised 906,359 women and men (66.9
We investigated the effects of commercial fungicides on the Japanese mycoparasitic Ampelomyces sp. (AM) strain Xs-q, considered to be a promising biocontrol agent of powdery mildew (PM) fungi, in two settings: (a) in vitro assays; and (b) in vivo assays with a melon PM isolate (Podosphaera xanthii KMP-6N) on leaves of host seedlings (Cucumis melo 'Earl's Favourite'). When Xs-q was inoculated onto nutrient media supplemented with one of 37 fungicides, 12 of these, including pyriofenone and mepanipyrim, failed to inhibit its growth and the production of pycnidia. We also used a digital microscope to monitor Xs-q in fungicide-resistant KMP-6N colonies. In the presence of fungicides, Xs-q hyphae penetrated the KMP-6N hyphae and grew internally. Under greenhouse conditions (low RH, 30%-55%), at 7 days post-inoculation (dpi) with Xs-q spores, the KMP-6N conidiophores and hyphae atrophied and collapsed. Under growth chamber conditions (high RH, 80%-90%), at approximately 7-10 dpi, Xs-q hyphae produced intracellular pycnidia in KMP-6N conidiophores and at approximately 10-14 dpi, Xs-q released spores from its mature pycnidia. Pycnidia of Xs-q were formed in KMP-6N colonies pretreated with the fungicide kresoxim-methyl. When combined with fungicides, the mycoparasitic fungus inhibited the development of the fungicide-resistant fungus, which failed to release progeny conidia from the PM colonies, regardless of the relative humidity. Our study is the first to demonstrate biotrophic interactions between an AM strain and a fungicide-resistant P. xanthii in the presence of a fungicide on host leaves, by combining digital microscopic and electrostatic techniques.
Molecular cocrystals are crystalline materials composed of multiple types of molecular components held together by noncovalent interactions. Among these, porphyrin-fullerene cocrystals represent a well-studied class of supramolecular assemblies. The close packing arrangement between porphyrins and fullerenes is known to contribute to high crystallinity and structural stability. Porphyrin-fullerene cocrystal systems including C60, which has a spherical shape, have provided insights on intermolecular interaction. In contrast, cocrystals incorporating C70, which has an ellipsoidal shape, remain relatively unexplored, and the influence of fullerene shape on cocrystal structures and stability remains unclear. In this study, we investigate the differences between C60 and C70 using cocrystals of a nickel(ii) porphyrin derivative (NiTEPP) with these fullerenes. Two distinct cocrystals were successfully obtained: the porous cocrystal NiTEPP/C70 featuring one-dimensional channels, and the nonporous crystal NiTEPP/C70-n. High-pressure single-crystal X-ray diffraction results show that these cocrystals maintained their single crystal structure under high pressure. Furthermore, intermolecular interaction energies depending on the fullerene species were evaluated using density functional theory calculations. The combined experimental and theoretical results demonstrate that the shape of the fullerene plays a crucial role in governing intermolecular interactions and structural stability, and these results provide valuable guidelines for the rational design of molecular cocrystals with controlled intermolecular interactions.
The uneven distribution of universities across regions has been argued to create educational inequalities based on place of residence. While studies have shown positive associations between college proximity, measured by distance to nearest college or its presence, and enrolment among local residents, regional availability has often been measured insufficiently, and longitudinal evidence on the relationship is limited. Using multiple social survey datasets combined with population census data from Japan, a country that has experienced significant policy shifts regarding university locations, we examine how longitudinal changes in regional university availability in an individual's residential and neighbouring prefectures are associated with their likelihood of university enrolment and how these associations differ by parental class and education. Our results show that increased university availability in both residential and neighbouring prefectures is positively associated with enrolment. While the strength of the association does not differ significantly by parental class, individuals with tertiary-educated parents are more responsive to increased availability. These findings suggest that increased university availability in underserved areas could reduce spatial inequality in enrolment, though may have a limited role in reducing, or may even be positively associated with, inequality based on social origin.
