University of Tsukuba

Shake-gels—mixed suspensions of silica nanoparticles and poly(ethylene oxide)—exhibit reversible sol-gel transitions, which are triggered by agitation and reversed by rest. Despite their unique reversibility, the mechanisms governing shake-gel formation and relaxation, as well as the parameters controlling their macroscopic mechanical properties, remain poorly understood. According to the findings of previous studies based on visual observations, the relaxation time of shake-gels exhibits a maximum at an intermediate polymer dose per particle surface area. However, a quantitative rheological characterization of these relaxation behaviors has been lacking. Here, we systematically investigated the time evolution of the storage modulus of shear-induced gels as a function of polymer dose per particle surface area ( C p ) using time-resolved viscoelastic measurements. The initial storage modulus increased with C p and reached a plateau at approximately C p = 0.03 mg/m 2 . Conversely, the relaxation time underwent a precipitous decline above this C p . These results suggest that both high elasticity and prolonged structural stability emerge around the intermediate C p . The observed nonmonotonic dependence on C p persists across different particle concentrations and polymer molecular weights, indicating that normalization by particle surface area provides a useful framework for comparing relaxation behavior across compositions. These results establish a quantitative rheological basis for interpreting previously reported visual observations and offer guidance for the design of tunable, reversible gel systems.

• Stress alters pigment production and composition in Talaromyces purpureogenus • EtOH and H 2 O 2 addition increases red pigment productivity • T. purpureogenus pigments exhibit anti-glycation activity • Fungal pigments show potential as sustainable, functional food dyes Biological pigment production has become increasingly important because of adverse health effects associated with chemical dyes. The fungus Talaromyces purpureogenus has been used to produce extracellular water-soluble red pigments similar to those produced by Monascus . Several studies have investigated Monascus pigment production under certain stress conditions; however, few have examined extracellular pigment production in Talaromyces . Furthermore, little research has been conducted on the use of fungal pigments as functional food dyes. Therefore, we evaluated the ability of T. purpureogenus to withstand abiotic stress in cultivation media and the effects of stress on pigment productivity. Abiotic stress was induced via the addition of sodium chloride (NaCl), sea salts, ethanol (EtOH), and hydrogen peroxide (H 2 O 2 ). Stressful conditions altered pigment production and composition. An increase in yellow-to-red pigment production ratio was observed under saline stress with both NaCl and sea salts. The yield of yellow pigment increased 1.44-fold in the presence of 1% (w/v) NaCl, while the yellow-to-red pigment ratio rose from 1.59 to 3.88 in the presence of 2% (w/v) sea salts. Addition of 1% (v/v) EtOH and 0.5% v/v H 2 O 2 (30% w/w) increased red pigment production by 2.59- and 1.67-fold, respectively. Differences in colourant properties were highlighted using UV-Vis and fluorescence spectroscopic measurements. Partially purified pigments inhibited bovine serum albumin glycation in the presence of ᴅ-ribose, demonstrating their potential to prevent the formation of advanced glycation end products. Overall, these findings demonstrated that stress conditions can improve pigment productivity in T. purpureogenus and highlight the possibility of producing functional food dyes.

Evidence suggests an association between interoceptive processing, which originates from feelings in the body, and mental health-related status, such as anxiety. We assessed heartbeat interoceptive accuracy, interoceptive sensibility, and awareness among 26 adults who stutter (AWS) and 26 those who do not stutter (AWNS) as controls. Heartbeat perception accuracy was measured via a heartbeat-tracking task in which participants counted their heartbeats in six trials of varying durations. Interoceptive sensibility was assessed via interoception questionnaires, which included the Body Perception Questionnaire and Multidimensional Assessment of Interoceptive Awareness. The area under the curve (AUC) in the heartbeat-discrimination task, in which participants judged the synchronization of their heartbeat and 10 tones with synchronized/not synchronized timing, was used to calculate interoceptive awareness. Interoceptive trait prediction error (ITPE) was also calculated via the Z-score differences between behavioral accuracy and self-reported sensibility. Our findings revealed significant differences in the interoception questionnaire scores (p=.013), which indicated a unique interoceptive pattern in AWS. Although no significant differences were observed in heartbeat-tracking performance (p=.188) and AUC (p=.131), a significant difference was observed in ITPE (p=.013), which suggested that AWS exhibited superior heartbeat perception accuracy compared with AWNS. Our study, the first to investigate multidimensional interoception in AWS, revealed distinct interoceptive patterns. These patterns were not explained by participants' age, co-occurring disorders scores, or stuttering severity, which indicated the need for further research to understand the relevance of interoception in stuttering mechanisms, anticipation, and treatment.

Exercise therapy is important for exercise tolerance, for the prevention of frailty or sarcopenia, and to improve quality of life (QOL). Previous studies, including systematic reviews, have shown the efficacy of exercise therapy for kidney transplant recipients (KTRs), but the optimal types of exercise remain unclear. Therefore, we aimed to synthesize the published evidence and compare the efficacy of types of exercise. We systematically searched for randomized controlled trials of the efficacy of exercise therapy in KTRs on PubMed and Ichushi, then performed a meta-analysis. Exercise was categorized as aerobic training (AT), resistance training (RT), or AT + RT. The risk of bias was assessed using ROB2 and the certainty of the evidence was evaluated using the GRADE approach. Twenty-five studies were included in the study and 18 in the meta-analysis. Exercise was associated with significant improvements in QOL (SF-36 physical functioning score), cardiorespiratory function (VO2peak), physical function (performance in the 6-min walk test (6MWT) and sit/stand test (STS)), and a metabolic index (triglyceride concentration). Kidney function tended to be superior in the exercise group, but the difference was not significant. Other indices of glucose and lipid metabolism and the incidence of hospitalization did not differ between the Exercise and Control groups. AT + RT significantly improved VO2peak, 6MWT performance, and the triglyceride concentration, whereas AT alone did not improve VO2peak and RT alone did not improve 6MWT performance or the triglyceride concentration. The certainty of the evidence was generally "low" or "very low". Exercise therapy improved the QOL, cardiorespiratory function, physical function, and triglyceride concentration of KTRs. The AT + RT combination may be the most effective exercise therapy for such patients.

Dynamic interfacial tension (DIT) measurements are widely employed to investigate the adsorption kinetics of surfactants due to their high interfacial selectivity. However, their application to other interfacial processes, such as solvent extraction and interfacial chemical reactions, remains limited. In this study, we investigated the extraction kinetics of ibuprofen (Ibu) using β-cycloyoubaidextrin (CD) in a hexane/water system via DIT measurements. Ibu, initially present in the hexane phase, was transferred to the water phase through interfacial complexation with CD. The interfacial tension (γ) decreased during the extraction process, indicating that the interfacial reaction of Ibu and CD influenced γ. The system involves multiple elementary steps: the adsorption/desorption of CD, the interfacial complexation, and the desorption of the resulting complex into the water phase. The rate constants (k) for these processes were determined by fitting the experimental data to kinetic models derived from these elementary steps. The estimated k values were as follows: adsorption/desorption of CD, (53-99) L mol-1s-1 and (1.4-3.4)×10-2 s-1, respectively; complexation/dissociation of Ibu, (3.0-12)×104m2mol-1s-1 and (4.2-16)×10-2 s-1, respectively; and complex desorption, (1.0-3.1)×10-4 s-1. These results highlight the capability of DIT measurements to resolve interfacial reaction kinetics in multiphase systems with high temporal resolution. This approach not only expands the analytical applications of interfacial tension techniques beyond surfactant systems but also provides a powerful tool for studying dynamic host-guest interactions relevant to extraction, separation, and sensing technologies.