Exploring perceived difficulty of graded reader texts

Although proponents of extensive reading (ER) have recommended easy reading material, book difficulty has been poorly defined and operationalized in previous studies. The present study argues for the use of perceived text difficulty for operationalizing book difficulty based on empirical findings (Holster et al., 2017), reading purposes in ER, and the importance of readers’ perspectives. A total of 162 Japanese English-as-a-foreign-language university students rated the difficulty of 15 texts excerpted from graded readers (GRs). The data were analyzed by conducting a many-facet Rasch analysis (Linacre, 1989; Rasch, 1960/1980), where a rating scale model (Andrich, 1978) was tested with persons, texts, and graded readers’ levels as the facets of measurement. The results revealed that perceived text difficulty could not replicate the stated difficulty level provided by the GR publisher, reinforcing the necessity of examining perceived text difficulty in ER research and practice in the second and foreign language classroom

Perceived Book Difficulty and Pleasure Experiences as Flow in Extensive Reading

In second or foreign language (L2) extensive reading (ER) studies, learners have been encouraged to read easy books despite the lack of consensus concerning how to define book difficulty. In light of previous studies reporting that book difficulty can play an important role in learners’ affect in ER (e.g., Bahmani & Farvardin, 2017; Chiang, 2016; Yang et al., 2021), the present study explored the relationship between perceived book difficulty and pleasure experiences from the perspective of the flow theory (Csikszentmihalyi, 1975/2000), as an important reading purpose in ER is for pleasure. Ninety-nine Japanese university students participated in a flow questionnaire survey, five of whom also participated in the follow-up interviews. It was found that some characteristics of flow were found in relation to the difference in perceived book difficulty, and that the participants’ perceptions were affected by some factors related to the flow theory

Low temperature dielectric and magnetic properties of Fe-ion-doped SrTiO₃

Dielectric and magnetic properties of SrTi1−xFexO3 were measured for a single crystal sample (x=0.0032) and a ceramic sample (x=0.02). Temperature dependences of the dielectric constants were analyzed on the basis of a Vendik\u27s formula, which describes a quantum paraelectric state accurately. A small amount of Fe impurities in the single crystal does not affect the characteristic temperatures of the dielectric properties, but does affect the quality of the crystal. This change in quality causes a large change in the dielectric constant of the quantum paraelectric state. The temperature dependence of the dielectric constant of the quantum paraelectric state of the ceramic sample is different from that of the single crystal not only quantitatively, but also qualitatively. The magnetic susceptibilities obey the typical Curie law, though a deviation of the Curie law was observed below 5 K for x=0.02. Crystals with the both concentrations remain in paramagnetic states at 2.5 K. The magnetic properties of SrTi1−xFexO3 can, in all likelihood, be explained by the orientation effect of free Fe3+ions. In addition, an antiferroelectric interaction suggested for EuTiO3 by an analysis of dielectric constants based on a Barrett\u27s formula was turned out to be unnecessary following analysis of the same data based on the Vendik\u27s formula.Embargo Period 12 month

Spatial Distributions of GABA Receptors and Local Inhibition of Ca2+ Transients Studied with GABA Uncaging in the Dendrites of CA1 Pyramidal Neurons

GABA(γ-amino-butylic acid)-mediated inhibition in the dendrites of CA1 pyramidal neurons was characterized by two-photon uncaging of a caged-GABA compound, BCMACM-GABA, and one-photon uncaging of RuBi-GABA in rat hippocampal slice preparations. Although we found that GABAA-mediated currents were diffusely distributed along the dendrites, currents elicited at the branch points of the apical dendritic trunk were approximately two times larger than those elsewhere in the dendrite. We examined the inhibitory action of the GABA-induced currents on Ca2+ transients evoked with a single back-propagating action potential (bAP) in oblique dendrites. We found that GABA uncaging selectively inhibited the Ca2+ transients in the region adjacent (<20 µm) to the uncaging site, and that GABA uncaging was effective only within a short period after bAP (<20 ms). The strength of inhibition was linearly related to the amplitudes of the GABA currents, suggesting that the currents inhibited a sustained, subthreshold after-depolarization without preventing propagation of bAP. GABA uncaging at the dendritic branch points inhibited Ca2+ transients farther into dendritic branches (>20 µm). Our data indicate that GABA inhibition results in spatially confined inhibition of Ca2+ transients shortly after bAP, and suggest that this effect is particularly potent at the dendritic branch points where GABA receptors cluster

Relationship between respiratory function assessed by spirometry and mild cognitive impairment among community-dwelling older adults

Tachibana Y., Godai K., Kabayama M., et al. Relationship between respiratory function assessed by spirometry and mild cognitive impairment among community-dwelling older adults. Geriatrics and Gerontology International, (2024); https://doi.org/10.1111/ggi.14962.Aim: Aging is a major cause of cognitive dysfunction. It has also been reported that respiratory function may influence cognitive dysfunction. However, few studies have examined the relationship between cognitive function and respiratory function among community-dwelling older adults. This study aims to determine the relationship between respiratory function, assessed using spirometry, and mild cognitive impairment (MCI) in community-dwelling older adults. Methods: This study included 419 participants aged 73 ± 1 years and 348 participants aged 83 ± 1 years from the SONIC cohort study (Septuagenarians Octogenarians Nonagenarians Investigation with Centenarians Study). Respiratory function was evaluated using %Vital Capacity (%VC), Forced Expiratory Volume 1 s (FEV1)/Forced Vital Capacity (FVC), and %Peak Expiratory Flow (%PEF). Airflow-limitation presence and stages were classified using FEV1/FVC. Cognitive function and MCI were assessed using the Japanese version of the Montreal Cognitive Assessment (MoCA-J). Results: The MoCA-J score exhibited a declining trend as the airflow-limitation stage increased among study participants in the 83 ± 1 age group. The presence of airflow limitation was associated with MCI in the 83 ± 1 age group. Among the indicators of each respiratory function, low %PEF was found to be associated with an increased rate of MCI. Furthermore, low %VC has also been suggested to be associated with an increased rate of MCI in the 83 ± 1 age female group. Conclusions: Advanced airflow-limitation stages may exacerbate cognitive dysfunction in community-dwelling older adults. The presence of airflow limitation and low %VC may also be associated with cognitive dysfunction in older women. Consequently, reduced respiratory function may potentially be associated with MCI in community-dwelling older adults

Usefulness of the serum creatinine/cystatin C ratio as a blood biomarker for sarcopenia components among age groups in community-dwelling older people: The SONIC study

Fang W., Godai K., Kabayama M., et al. Usefulness of the serum creatinine/cystatin C ratio as a blood biomarker for sarcopenia components among age groups in community-dwelling older people: The SONIC study. Geriatrics and Gerontology International , (2024); https://doi.org/10.1111/ggi.14876.Aim: The serum creatinine/cystatin C ratio (CCR) or sarcopenia index is considered a useful marker of muscle mass. However, its usefulness in late-stage older adults remains unclear. We aimed to determine the usefulness of CCR as an indicator of sarcopenia in community-dwelling Japanese adults aged >75 years. Methods: Our study recruited participants aged 70, 80, and 90 ± 1 years during the baseline years, and included a 3-year follow-up in the Septuagenarians, Octogenarians, Nonagenarians, Investigation with Centenarians study. From 2015 to 2018, 955 participants were eligible: 367 in their 70s, 304 in their 80s, and 284 in their 90s. The diagnostic components of sarcopenia, including “low muscle mass, plus low muscle strength, and/or low physical performance,” were evaluated using the bioelectrical impedance analysis-measured skeletal muscle mass index (SMI), handgrip strength, and short physical performance battery (SPPB) score, respectively, in accordance with the Asia Working Group for Sarcopenia 2019 criteria. Separate analyses were performed between each component and CCR, adjusting for sex, body mass index, and other blood biomarkers in each group. Results: The relationship between CCR and sarcopenia components was significant for handgrip strength (β = 0.21, 0.13, 0.19, and P < 0.0001, =0.0088, <0.0001, for the 70s, 80s, and 90s age groups, respectively); however, it was limited for SMI (β = 0.14; P = 0.0022, only for the 90s) and not significant for the SPPB score. Conclusion: CCR is a limited indicator of sarcopenia in late-stage older adults. Although its association with muscle strength was significant, its relationship with muscle mass and physical performance was less pronounced

Risk factors predicting subtypes of physical frailty incidence stratified by musculoskeletal diseases in community-dwelling older adults: The SONIC study

Ohata Y., Godai K., Kabayama M., et al. Risk factors predicting subtypes of physical frailty incidence stratified by musculoskeletal diseases in community-dwelling older adults: The SONIC study. Geriatrics and Gerontology International, (2024); https://doi.org/10.1111/ggi.14924.Aim: This study aims to identify the key risk factors that lead to subtypes of physical frailty assessed by walking speed and grip strength among community-dwelling Japanese individuals, stratified by the presence of musculoskeletal diseases (MSDs) and age group. Methods: We included 302 participants aged 70 or 80 years who did not exhibit subtypes of physical frailty at baseline through the Septuagenarians, Octogenarians, Nonagenarians, Investigation with Centenarians (SONIC) study. Our study was a longitudinal study. The outcome was the incidence of subtypes of physical frailty after 3 years. Subtypes of physical frailty were defined as a weak grip strength or slow walking speed, or both, based on the Japanese version of the Cardiovascular Health Study Index. The risk factors for subtypes of physical frailty incidence were examined by age group and MSD, using multivariate logistic regressions. Results: Of the 302 participants, 110 (36.4%) had MSD. Those with MSD were significantly more likely to have subtypes of physical frailty after 3 years compared with those without MSD. Among all participants, older age was a risk factor of subtypes of physical frailty (P < 0.05). Without MSD, older age and dissatisfied financial status were risk factors (P < 0.05). With MSD, older age was a risk factor (P < 0.05). By age group, in individuals aged 70 years old, a dissatisfied financial status was a risk factor for those without MSD (P < 0.05), and a higher BMI was one for those with MSD (P < 0.05). Conclusions: Older age was a risk factor for subtypes of physical frailty, but other risk factors differed according to the presence of MSD and age

Autosomal dominant pseudohypoaldosteronism type 1 with a novel splice site mutation in MR gene

<p>Abstract</p> <p>Background</p> <p>Autosomal dominant pseudohypoaldosteronism type 1 (PHA1) is a rare inherited condition that is characterized by renal resistance to aldosterone as well as salt wasting, hyperkalemia, and metabolic acidosis. Renal PHA1 is caused by mutations of the human mineralcorticoid receptor gene (<it>MR</it>), but it is a matter of debate whether <it>MR </it>mutations cause mineralcorticoid resistance via haploinsufficiency or dominant negative mechanism. It was previously reported that in a case with nonsense mutation the mutant mRNA was absent in lymphocytes because of nonsense mediated mRNA decay (NMD) and therefore postulated that haploinsufficiency alone can give rise to the PHA1 phenotype in patients with truncated mutations.</p> <p>Methods and Results</p> <p>We conducted genomic DNA analysis and mRNA analysis for familial PHA1 patients extracted from lymphocytes and urinary sediments and could detect one novel splice site mutation which leads to exon skipping and frame shift result in premature termination at the transcript level. The mRNA analysis showed evidence of wild type and exon-skipped RT-PCR products.</p> <p>Conclusion</p> <p>mRNA analysis have been rarely conducted for PHA1 because kidney tissues are unavailable for this disease. However, we conducted RT-PCR analysis using mRNA extracted from urinary sediments. We could demonstrate that NMD does not fully function in kidney cells and that haploinsufficiency due to NMD with premature termination is not sufficient to give rise to the PHA1 phenotype at least in this mutation of our patient. Additional studies including mRNA analysis will be needed to identify the exact mechanism of the phenotype of PHA.</p

A Novel Enzymatic System against Oxidative Stress in the Thermophilic Hydrogen-Oxidizing Bacterium Hydrogenobacter thermophilus

Rubrerythrin (Rbr) is a non-heme iron protein composed of two distinctive domains and functions as a peroxidase in anaerobic organisms. A novel Rbr-like protein, ferriperoxin (Fpx), was identified in Hydrogenobacter thermophilus and was found not to possess the rubredoxin-like domain that is present in typical Rbrs. Although this protein is widely distributed among aerobic organisms, its function remains unknown. In this study, Fpx exhibited ferredoxin:NADPH oxidoreductase (FNR)-dependent peroxidase activity and reduced both hydrogen peroxide (H2O2) and organic hydroperoxide in the presence of NADPH and FNR as electron donors. The calculated Km and Vmax values of Fpx for organic hydroperoxides were comparable to that for H2O2, demonstrating a multiple reactivity of Fpx towards hydroperoxides. An fpx gene disruptant was unable to grow under aerobic conditions, whereas its growth profiles were comparable to those of the wild-type strain under anaerobic and microaerobic conditions, clearly indicating the indispensability of Fpx as an antioxidant of H. thermophilus in aerobic environments. Structural analysis suggested that domain-swapping occurs in Fpx, and this domain-swapped structure is well conserved among thermophiles, implying the importance of structural stability of domain-swapped conformation for thermal environments. In addition, Fpx was located on a deep branch of the phylogenetic tree of Rbr and Rbr-like proteins. This finding, taken together with the wide distribution of Fpx among Bacteria and Archaea, suggests that Fpx is an ancestral type of Rbr homolog that functions as an essential antioxidant and may be part of an ancestral peroxide-detoxification system

Diversity of Melissococcus plutonius from Honeybee Larvae in Japan and Experimental Reproduction of European Foulbrood with Cultured Atypical Isolates

European foulbrood (EFB) is an important infectious disease of honeybee larvae, but its pathogenic mechanisms are still poorly understood. The causative agent, Melissococcus plutonius, is a fastidious organism, and microaerophilic to anaerobic conditions and the addition of potassium phosphate to culture media are required for growth. Although M. plutonius is believed to be remarkably homologous, in addition to M. plutonius isolates with typical cultural characteristics, M. plutonius-like organisms, with characteristics seemingly different from those of typical M. plutonius, have often been isolated from diseased larvae with clinical signs of EFB in Japan. Cultural and biochemical characterization of 14 M. plutonius and 19 M. plutonius-like strain/isolates revealed that, unlike typical M. plutonius strain/isolates, M. plutonius-like isolates were not fastidious, and the addition of potassium phosphate was not required for normal growth. Moreover, only M. plutonius-like isolates, but not typical M. plutonius strain/isolates, grew anaerobically on sodium phosphate-supplemented medium and aerobically on some potassium salt-supplemented media, were positive for β-glucosidase activity, hydrolyzed esculin, and produced acid from L-arabinose, D-cellobiose, and salicin. Despite the phenotypic differences, 16S rRNA gene sequence analysis and DNA-DNA hybridization demonstrated that M. plutonius-like organisms were taxonomically identical to M. plutonius. However, by pulsed-field gel electrophoresis analysis, these typical and atypical (M. plutonius-like) isolates were separately grouped into two genetically distinct clusters. Although M. plutonius is known to lose virulence quickly when cultured artificially, experimental infection of representative isolates showed that atypical M. plutonius maintained the ability to cause EFB in honeybee larvae even after cultured in vitro in laboratory media. Because the rapid decrease of virulence in cultured M. plutonius was a major impediment to elucidation of the pathogenesis of EFB, atypical M. plutonius discovered in this study will be a breakthrough in EFB research