Nakamura Gakuen University

The triplet–triplet annihilation (TTA)-assisted photon upconversion (PUC) properties of a solution system comprised of the newly developed acceptor di(p-anisyl)tetrahydropentalene TP-An, containing a rigidly constrained planar diene subunit were elucidated. Due to its symmetric and rigid molecular structure, TP-An undergoes rapid fluorescence emission and slow nonradiative processes, respectively, which give rise to its unity fluorescence quantum yield and its short singlet excited state lifetime of 1.13 ns in degassed toluene. Its rigid structure gives TP-An a long triplet excited state lifetime of 654 ms, which is required for efficient TTA-PUC. Moreover, the experimentally determined singlet (ES, 3.22 eV) and triplet (ET, 1.62–1.79 eV) excited state energy levels of TP-An meet the requirements for exergonic TTA (ES < 2ET). Analysis of the TTA-PUC behavior reveals that a toluene solution of TP-An and platinum octaethylporphyrin as a donor displays a record low threshold excitation intensity of 10 mW cm–2 and a high PUC quantum yield up to ca. 23%. Results of this study provide critical information about the design of acceptor molecules that are components of highly efficient green-to-purple TTA-PUC systems.

Abstract Pumice often floats on water, and there is a large variation in the length of time it floats. We investigated the factors that influence the flotation time of pumice from Sakurajima volcano, Japan, and how water infiltrates in the pumice. Five air-fall samples of different sizes and porosities were immersed in water and the time they floated was evaluated. The flotation time varied from almost immediately sinking to more than 10 days, and a clear correlation between flotation time and sample size was not observed within the range of 2–39 cm 3 . From the measured values of the total porosity, connected porosity, transport porosity, dead-end porosity, and isolated porosity of each sample, it was found that there was a strong correlation between the flotation time and total porosity, connected porosity, and dead-end porosity. In order to investigate the size of the pores and the order in which water enters them, the amount of water in each pore radius was measured under three conditions: when the sample was immersed in water for 10 min or 3 days, and when all the pores were filled with water. Samples with a low porosity sank rapidly because enough water entered the interior to lose buoyancy due to the initial rapid capillary imbibition. At this stage, water was found to enter the large-radius pores preferentially. Samples with a high porosity did not sink by initial process, but eventually sank. Water infiltration during this period was found to be more pronounced in dead-end pores than in transport pores. In the experimental method adopted in this study, water present in the corners and walls of the pores was regarded as water in the dead-end pores, and it is presumed that an increase in such water and the dissolution of entrapped air occurred in the later stage.

<title>Abstract</title> Background Definitive hematopoietic stem cells (HSCs) emerge within intra-aortic hematopoietic cell clusters (IAHCs) located in the dorsal aorta of the aorta-gonad-mesonephros (AGM) region during midgestation in the mouse embryo. Thereafter, HSCs migrate to the fetal liver (FL) and finally settle in the bone marrow (BM). We previously showed that the transcription factor Sox17 is expressed in IAHCs. Transduction of the <italic>Sox17</italic> gene in IAHC cells induces the formation of cell clusters in vitro that resemble IAHCs and retain hematopoietic potential. In addition, a previous report showed that <italic>Sox17</italic> -transduced hematopoietic stem/progenitor cells (HSPCs) in the BM maintained pluripotency. However, the relationship between Sox17-induced cluster formation and the developmental transition from fetal to adult hematopoiesis has not been clarified. Methods We examined whether viral transduction of the <italic>Sox17</italic> gene in HSPCs leads to the formation of cell clusters. To identify the candidate genes involved in cluster formation, we performed RNA-sequencing (RNA-seq) analysis on <italic>Sox17-ER</italic> T-transduced HSPCs from the AGM region and the BM cultured with or without tamoxifen. We further analyzed the ability of one candidate gene, the <italic>Procr</italic> gene, to support cluster formation and hematopoietic function. Results A large number of multilineage colonies were observed in <italic>Sox17-ERT</italic> -transduced tamoxifen-treated HSPCs prepared from the AGM region, the FL, and the BM. However, the ability to form cell clusters was lower in BM-derived HSPCs compared to those from the AGM region and the FL. RNA-seq analysis revealed several genes that were highly expressed in <italic>Sox17-ERT</italic> -transduced tamoxifen-treated HSPCs from the AGM region. The <italic>Procr</italic> gene, one of these genes, was expressed in IAHCs and was found to contribute to both cluster formation and the maintenance of hematopoietic capacity in <italic>Sox17</italic> -transduced cells of the AGM region. Conclusions Our results revealed that the Sox17-induced cluster-forming ability is attenuated in BM HSPCs compared to the AGM and the FL HSPCs, suggesting that HSPC characteristics are developmentally altered during the transition from fetal to adult hematopoiesis. Moreover, the <italic>Procr</italic> gene plays a substantial role in cluster formation and supports hematopoietic capacity in the midgestation mouse embryos.

わが国における糖質科学分野の技術力は高く，新規糖質の開発が盛んである．これらの新規糖質は生体内で各々特徴的な代謝経路を有しており，その特性を活用して実用化されている．新規糖質の中には，経口摂取後，消化管腔内において生体由来の糖質消化酵素によって消化されにくい，かつ/または，吸収されにくい特徴を有する難消化吸収性糖質がある．その代謝的特徴から難消化吸収性糖質は，低エネルギーの甘味料（難吸収性単糖や糖アルコールなど）あるいは，澱粉の代替（食物繊維）として加工食品に利用されている．難消化吸収性糖質を食品素材として商品・実用化する際の食品表示上の課題として，熱量算出時のエネルギー換算係数および分類がある．本稿では，難消化吸収性糖質のエネルギー換算係数の評価方法および運用に関する（一社）日本食物繊維学会の取り組みに関して簡単に紹介する．また，海外における難消化吸収性糖質の食品表示ならびに製品開発における難消化吸収性糖質の利用について紹介し，我が国の難消化吸収性糖質・糖類の食品表示上の分類に関する課題を共有する．

Postprandial hyperglycemia is a risk factor not only for diabetes mellitus, but also arteriosclerosis. Therefore, controlling the rapid postprandial increase in blood glucose levels is necessary. This study aimed to develop a mulberry leaf and water chestnut husk tea and investigate its effect on postprandial blood glucose levels. We measured the polyphenols and 1-deoxynojirimycin contents as well as antioxidant activity of mulberry leaf and water chestnut husk tea in an in vitro experiment. The effect of the tea on postprandial blood glucose levels in 30 participants with borderline diabetes was investigated in a randomized, double-blind, placebo-controlled crossover comparison study. The 1-deoxynojirimycin and total polyphenol contents in the tea (test food, 3g) were 10.2±0.8 and 61.3±1.4 mg, respectively. The test food showed higher antioxidant activity than the placebo food. Compared with those in the placebo group, blood glucose levels in the test group significantly decreased 30 and 60 min after eating rice. Additionally, insulin was significantly lower at all time points (30, 60, 90, and 120 min after rice consumption). The mulberry leaves and water chestnut mix tea may be an effective beverage to reduce insulin secretion and prevent rapid increases in blood glucose levels in patients with borderline diabetes.

Amyloid fibril formation is associated with various amyloidoses, including neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Despite the numerous studies on the inhibition of amyloid formation, the prevention and treatment of a majority of amyloid-related disorders are still challenging. In this study, we investigated the effects of various plant extracts on amyloid formation of α-synuclein. We found that the extracts from Eucalyptus gunnii are able to inhibit amyloid formation, and to disaggregate preformed fibrils, in vitro. The extract itself did not lead to cell damage. In the extract, miquelianin, which is a glycosylated form of quercetin and has been detected in the plasma and the brain, was identified and assessed to have a moderate inhibitory activity, compared to the effects of ellagic acid and quercetin, which are strong inhibitors for amyloid formation. The properties of miquelianin provide insights into the mechanisms controlling the assembly of α-synuclein in the brain.

The objectives of this online study were to determine the status of regular dental check-ups among Thai nationals living in Japan and to identify barriers to regular dental check-ups by comparing them with general health check-ups. We conducted the online survey twice, in 2021 and 2022, among Thai nationals aged 18years and older living in Japan via social networking services by an organization that supports Thai nationals living in Japan. Respondents between the ages of 30 and 59 were included in this study. Independent factors included gender, age, length of stay in Japan, family economic status, confidence in Japanese and stay for work purposes. Dependent factors were regular dental check-ups and general health check-ups in the past year. Chi-square tests and multiple logistic regression analyses were used for analysis. 56.6% of respondents had regular dental check-ups. The adjusted odds ratio for the proportion of people with regular dental check-ups was significantly higher for those with high economic status, 2.15 (1.06-4.33), compared with those with low economic status. It was also significantly higher 1.88 (1.10-3.21) for those with confidence in the Japanese language compared with those without. The study suggested the need for Japanese language support in addition to financial support for dental health prevention programs for foreigners living in Japan.

The emergence of Klebsiella pneumoniae harboring the bla IMP-6 plasmid poses an escalating threat in Japan. In this study, we found 29 newly isolated bacteriophages that infect K. pneumoniae strains carrying the pKPI-6 plasmid from clinical settings in western Japan. Our phages exhibited a broad host range. We applied a phage cocktail treatment composed of 10 phages against two host strains, Kp21 and Kp22, which displayed varying phage susceptibility patterns. Although the phage cocktail delayed the emergence of phage-resistant Kp21, it was unable to hinder the emergence of phage-resistant Kp22. Moreover, the phage-resistant Kp21 became sensitive to other phages that were originally non-infective to the wild-type Kp21 strains. Our study highlights the potential of a well-tailored phage cocktail in reducing the occurrence of phage-resistant bacteria.