Osaka University
  • Osaka, Japan
Recent publications
In the field of soft robotics, research on variable stiffness mechanisms that combine flexible structures for deformation with a solid structure for transmitting external forces is underway. This investigation is focused on a mechanism for achieving a high adjustable locking force with minimal actuators, enabling arbitrary shape locking. The paper introduces a novel shape-locking mechanism that utilizes the expansion force of a single rubber tube, which is positively pressurized with air, to generate frictional force. Positive pressurization facilitates clamping of wires and contact between joints, producing a joint holding torque. The holding torque in the mechanism is theoretically modeled and compared with its measured value in the bending directions of the prototype under an applied pressure. The results confirm that the holding torque increases in the presence of wires at each internal pressure value. Moreover, the holding torque, both with and without wires, is evaluated through a combination of theoretical models and actual measurements. These results demonstrate the viability of the proposed mechanism for the development of soft manipulators.
Bacillibactin (BB) is a microbial siderophore produced by Bacillus species. BB is biosynthesized from 2,3‐dihydroxybenzoic acid (2,3‐DHB), Gly, and L‐Thr by nonribosomal peptide synthetase (NRPS) enzymes DhbE, DhbB, and DhbF. The biosynthetic gene cluster (dhb) is also conserved in some strains of thermophilic genera, Geobacillus, Anoxybacillus and Parageobacillus. However, the production of BB from these thermophilic bacteria has not been characterized. Here, we report in vivo and in vitro characterization of BB biosynthesis in Parageobacillus sp. KH3‐4 which grows at 65 °C. We confirmed BB production in this thermophilic bacterium and the gene cluster active. In vitro enzymatic analysis revealed that 4′‐phosphopantetheinyltransferase (PPTase) encoded in the same gene cluster is responsible for the post‐translational maturation of carrier proteins. DhbE and DhbF showed substrate preference to 2,3‐DHB and Gly and L‐Thr, respectively, consistent with the chemical structure of BB. With the purified enzymes, we successfully reconstituted the NRPS assembly line in vitro. In addition, using chemically synthesized acyl‐N‐acetylcysteamine substrate analogues, BB analogues possessing methylbenzoyl groups instead of 2,3‐DHB were detected. This study provides a new insight into secondary metabolism in thermophiles, and it expands the temperature limitation of NRPS enzymes.
Molecular dynamics simulations were conducted using the generalized replica exchange method (gREM) on the 4-cyano-4′-n-alkyl biphenyl (nCB) system with n = 5, 6, 7, and 8, which exhibits a nematic–isotropic (NI) phase transition. Sampling near the phase transition temperature in systems undergoing first-order phase transitions, such as the NI phase transition, is demanding due to the substantial energy gap between the two phases. To address this, gREM, specifically designed for first-order phase transitions, was utilized to enhance sampling near the NI phase transition temperature. Free-energy calculations based on the energy representation (ER) theory were employed to characterize the NI phase transition. ER evaluates the insertion free energy of the nCB molecule for both nematic and isotropic phases, revealing a change in the temperature dependence across the NI phase transition. Further decomposition into energetic and entropic terms quantitatively shows the balance between these contributions at the NI phase transition temperature.
Purpose To investigate the safety and aesthetic outcomes of silicone buckle #506 for anophthalmic socket reconstruction. Study Design Retrospective cohort study. Methods Patients who underwent enucleation or evisceration at the Osaka University Hospital were retrospectively analyzed. Patients under 18 years old, with < 3 months follow-up, without a prosthesis, or with bilateral surgery were excluded. Aesthetic outcomes were assessed using standardized photographs taken 3 months postoperatively, scored by five independent ophthalmologists for upper eyelid sulcus deepening asymmetry. Scoring was categorized as 0: no noticeable side difference, 1: slight asymmetry, and 2: marked asymmetry characterized by upper eyelid sulcus deepening. Results Fifty-nine patients (60 sockets) were analyzed. Thirty-three received silicone buckle implants (1–4 buckles). Implant exposure occurred in two patients (6.1%). Aesthetic scores were assessed in 48 patients. Mean aesthetic scores were 0.97 (no implant), 0.78 (one buckle), 0.68 (two buckles), and 0.42 (three/four buckles) ( p = 0.123). Conclusions Silicone buckle #506 appears to be a safe and feasible option for anophthalmic socket reconstruction. Further studies are needed to optimize aesthetic outcomes and determine the ideal number of buckles.
To be precise, there is no classification called functional foods. What is commonly referred to as health foods may feel like functional foods, but legally, only “pharmaceuticals and other foods regulated by the Act on Securing Quality, Efficacy and Safety of Products Including Pharmaceuticals and Medical Devices” (Pharmaceuticals and Medical Devices Act) exist. However, there are foods for health use that are allowed to display functionality under certain conditions, and if anything, functional foods could be said to be foods for health use. Prior to 2015, in addition to pharmaceuticals regulated by the Pharmaceuticals and Medical Devices Act, there were nutritionally functional foods defined by the Health Promotion Act and Foods for Specified Health Use (FOSHU), and these two were health functional foods, with so-called health foods in the other category. So-called health foods are no different from ordinary foods from a legal perspective, and words like functionality and effect cannot be written. Therefore, abstract advertisements such as image advertisements that suggest knee rotation and personal impressions were the main focus, and consumers were not provided with the information necessary for purchase. In foreign countries such as the United States and the EU, functional displays are common, and there are few countries where functional displays cannot be made. As a result, it was prohibited in our country at that time, and we were in a situation where we could not tell what was real, and the overwhelming majority of inquiries from consumers were about the ingredients and intake methods of products, which did not match consumer needs. In a survey by the Consumer Committee, it was found that 60% of people wanted a functional display, and in our country, a new system of functional display foods, which allows the display of functionality based on notifications from companies, started in April 2015 (Fig. 105.1). Functional display foods have been accepted for over 6000 notifications by 2023, and it is said that they have formed a market of over 500 billion yen. With the advent of functional display foods, consumers can easily obtain foods that suit them, and self-care and self-medication have become more enriched.
Originally, describing functionality such as effects and efficacy in foods was prohibited under the “Act on Securing Quality, Efficacy and Safety of Products Including Pharmaceuticals and Medical Devices” (Pharmaceuticals and Medical Devices Act). The only exception was health foods approved by the Consumer Affairs Agency, which were traditionally limited to Foods for Specified Health Uses (FOSHU) and Foods with Nutrient Function Claims. However, the development costs for FOSHU are said to be several hundred million yen or more, and the review period can take several years, which has been heavily criticized. Therefore, Foods with Functional Claims, which allow companies to express functionality on the condition that evidence has been obtained in clinical trials, and which can be reported to the Consumer Affairs Agency under the responsibility of the company, were initiated in April 2015 to utilize research results conducted at universities and companies. By 2023, over 6000 cases have already been accepted, and the market size is estimated to be approaching 500 billion yen. The outline of Foods with Functional Claims is described in the “Guidelines for Notification of Foods with Functional Claims” posted on the Consumer Affairs Agency’s website (Fig. 106.1). Notifications are made online, and the content and clinical evidence are also described. The Consumer Affairs Agency checks the notification documents and, if there are no omissions or formal defects, issues a notification number and discloses the information on the Consumer Affairs Agency’s website, etc.
Macroautophagy (hereafter referred to as autophagy) is a large-scale degradation system that exists universally in eukaryotes. Autophagy is always occurring at low levels within our body’s cells, but it is strongly induced when cells detect starvation or various stresses. When autophagy is induced, a double-membrane structure called an autophagosome is created within the cell, which surrounds molecules and structures in the cytoplasm. The autophagosome then fuses with a lysosome, which contains a variety of hydrolytic enzymes, and the enclosed components are degraded and recycled (Fig. 22.1). Autophagy was traditionally thought of as a nonselective degradation system, but today it is known to exist as selective autophagy, which selectively removes organelles such as mitochondria, lysosomes, and endoplasmic reticulum (ER), aggregation-prone proteins, and invading bacteria. The membrane dynamics and molecular mechanisms of autophagy remained unclear for a long time, but the identification of a series of autophagy-related genes (ATG) through genetic analysis using yeast was a breakthrough, and the field has rapidly expanded over the past 30 years. Many reviews have been published on the detailed control mechanisms of autophagy, and readers are referred to these [1]. Through analysis so far, it has been found that autophagy not only secures necessary nutrients during starvation, but also plays a role in cellular metabolism and removal of harmful substances, and various physiological functions due to these actions are being revealed one after another. Below, I will introduce the involvement of autophagy in aging and lifespan control, which has become clear in recent years, and the potential for antiaging by autophagy.
The quantum spin-liquid state was first theorized by Anderson 50 years ago and the challenge remains to realize a quantum spin-liquid material. A handful of two-dimensional molecular candidates have attracted huge attention over the past 30 years owing to their triangular lattice possessing S = 1/2 spin systems. We present a new quantum spin-liquid candidate in 2D Mott insulator κ-(BEDT-TTF)2[BR/S(salicylate)]2. The structure has a double-width anion layer giving it a strong 2D character. The spiroborate anion is chiral and the salt is an inversion twin, having no inversion symmetry center and crystallizing in space group P21. This offers the possibility of novel behavior owing to the low symmetry not previously seen in molecular spin-liquid candidates. The peak height of the 6K anomaly of κ-(BEDT-TTF)2[BR/S(salicylate)2] is 2 or 3 times larger than that of κ-(BEDT- TTF)2Cu2(CN)3 and EtMe3Sb[Pd(dmit)2]2. The structure presents many opportunities for crystal engineering through atom-by- atom changes to the ligands on the spiroborate anion to produce a family of materials which lie in and around the QSL region of the phase diagram for these salts. This gives the prospect of an experimental playground to deepen understanding of the QSL state. Electrical resistivity, SQUID magnetometry, band calculations, heat capacity, Infrared and Raman spectroscopy are reported for κ- (BEDT-TTF)2[BR/S(salicylate)2].
We experimentally investigate the evolution and dynamics of laser-produced collisional blast waves (BW) under the influence of a perpendicular magnetic field up to 20 T. We show that an external magnetic field causes the BW to diverge from the Taylor–Sedov solution while also impacting its structural morphology. We notably explore the significance of various magnetohydrodynamic (MHD) processes occurring on scales similar to the width of the BW front by comparing their characteristic lengths to it and demonstrate that the downstream plasma's transition from being super- to sub-magnetosonic plays a pivotal role in the overall structure. Our results show that multiple MHD effects can contribute to shaping a magnetized BW, illustrating the complexity of the underlying physics.
Inadequate gestational weight gain (GWG) is associated with birth weight and premature birth and is a primary problem in Asia, particularly in Japan. This study aimed to identify the risk factors associated with inadequate GWG, focusing on women's target GWG and advised GWG by healthcare professionals. A questionnaire for women in their second trimester inquired about their target GWG and advice regarding GWG by healthcare professionals. Of the 626 participants, 52.6% were classified in the inadequate GWG group. Inadequate GWG was associated with a prepregnancy body mass index (BMI) < 18.5 kg/m² and weight below the prepregnancy weight in the second trimester. Among the multiparas, inadequate GWG was associated with an individual target GWG below the guideline, with no advice from healthcare professionals, and with an advised GWG below the guideline. Among the primiparas, there were no significant differences in the individual targets or advised GWG. Healthcare professionals must understand the latest guidelines regarding GWG and apply them when advising women. The importance of preconception care in achieving a BMI of at least 18.5 kg/m² before pregnancy is also suggested.
Background Care workers in long-term nursing homes often experience burdens and a high rate of resignations. This study aimed to investigate the mental health of care workers and to examine the relationship between the tendency to seek help and their mental health, through a comparison with the general population to address this issue. Methods Online surveys were conducted separately with 273 care workers and 260 general public using a questionnaire platform. They were asked about their demographic variables, mental health [the Kessler Psychological Distress Scale (K6) and stressors], help-seeking styles (self-directed, excessive, and avoidant help-seeking), and usage on use of psychological support services. The analyses were performed except for missing responses. Results Overall, 132 (48.4%) care workers scored higher than the cutoff point on the K6. Regarding stressors identified by the care workers, most of the contents were related to work-related matters and workplace relationships, as demonstrated through qualitative analysis. Hierarchical multiple regression analysis showed that the interaction term between each help-seeking style and participant group was non-significant. Meanwhile, age ( β = −0.116, p = 0.009), excessive help-seeking ( β = 0.120, p = 0.014), and avoidant help-seeking ( β = 0.331, p < 0.001) were associated with the K6. Conclusion This study revealed the tendency of care workers’ help-seeking behavior and its relationship to mental health. Improving care workers’ help-seeking skills and adjusting their work environment are essential for maintaining and enhancing their mental health.
Contemporary dynamical models of human postural control propose an intermittent controller regulating the postural centre of pressure (CoP) about a stable saddle-shaped manifold along anatomical anteroposterior (AP) and mediolateral (ML) axes, releasing CoP in an outwards spiral when inactive. Experimental manipulations can evoke this saddle-type topology in fractal temporal correlations along the AP axis and reducing correlations along the ML axis. However, true effects of task demands may often manifest within angular space between anatomical AP and ML axes—a space not typically modelled explicitly. We tested how instability and attentional load influence postural control across the full angular range of fractal variability along the two-dimensional (2D) support surface. Forty-eight healthy young adults performed a suprapostural Trail Making Test (TMT) while standing on a wobble board, inducing continuous perturbations along the ML axis. Stable, quiet standing exhibited classic saddle-like topology, with stronger fractal temporal correlations in CoP displacements along AP axes. The attentional demand of the TMT did not affect angular variation or strength of fractal temporal correlations across the 2Dsupport surface. However, maintaining upright balance on the wobble board reshaped and reoriented the angular distribution of fractal temporal correlations, accentuating saddle-like angular variation and rotating the strongest fractal temporal correlations predominantly along the ML axis. Stabilizing posture in the face of wobble board instability prompted the saddle-type angular distribution of fractal temporal correlations. These findings challenge the traditional dependence of postural control theories exclusively on external force-plate axes and underscore the significance of multifractality in defining control parameters that govern postural stability across the full angular range of the 2D support surface.
Purpose: To investigate the accuracy of proton density fat fraction (PDFF) measurement using chemical shift-encoded MRI (CSE-MRI) with fast imaging techniques in a phantom. Methods: A 1.5T imaging system (Prodiva; Philips Healthcare) and PDFF phantom (Fat Fraction Phantom Model 300; Calimetrix) were used in this study. The acquisitions without fast imaging techniques (conventional acquisition), with parallel imaging in phase-encode direction (SENSE acquisition), with compressed sensing (CS-SENSE acquisition), and with parallel imaging in both phase-encode and slice-encode direction (Dual-SENSE acquisition) were performed. The following acceleration factors in SENSE and CS-SENSE acquisition were used: 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, and 8.0. For Dual-SENSE acquisition, the same acceleration factors (1.5, 2.0, 3.0, 4.0, 5.0) were set in each of the two directions. The relationships between reference PDFF values and PDFF measurements obtained using each acquisition were assessed using linear regression analysis and Bland–Altman analysis. Results: According to the linear regression analysis, the slopes and intercepts of regression lines were from 0.87 to 1.02 and from 0.06% to 3.55%, respectively. According to Bland–Altman analysis, there were fixed bias between reference PDFF values and PDFF measurements obtained using SENSE acquisition with reduction factor 8.0 and Dual-SENSE acquisition with reduction factor 5.0. For CS-SENSE acquisition with reduction factor from 7.0 to 8.0, SENSE acquisition with reduction factor from 3.0 to 8.0, and Dual-SENSE acquisition with reduction factor from 2.0 to 5.0, some vials had ±1.5% or more errors between the reference PDFF values and PDFF measurements in the range of 0% to 50% PDFF. Conclusion: In CS-SENSE acquisition, the accuracy of PDFF measurement was maintained within 1.5% up to a reduction factor 6.0. The accuracy of PDFF measurement was maintained within 1.5% up to a reduction factor 2.0 in SENSE acquisition and a reduction factor 1.5 in Dual-SENSE acquisition.
Owing to the increasing severity of flood disasters in recent years caused by climate change, flood forecasting technologies are receiving increasing attention. For real-time river-stage forecasting, hybrid methods that combine the rainfall-runoff-inundation (RRI) model and machine-learning techniques have been actively researched. This study proposes a method for appropriately selecting calculated flow-rate input points and an effective deep neural network (DNN) structure for a hybrid method that employs a DNN to forecast river water levels using flow rates calculated by an RRI model and the observed river water levels. The results show that upstream flow rates, including that of each tributary, significantly contribute toward more accurate forecasts. Moreover, a hybrid-input ensemble neural network, which combines rainfall- and flow-rate-based DNN forecasts, improves the forecast accuracy by approximately 20% for a forecast lead time of up to 24 h compared with a simple DNN model. The proposed hybrid model demonstrated better forecasting accuracy than the simple DNN, even after training on a small amount of flood data, indicating its potential for application in cases with limited past observational data.
Gating is a fundamental process in ion channels configured to open and close in response to specific stimuli such as voltage across cell membranes thereby enabling the excitability of neurons. Here we report on voltage-gated solid-state nanopores by electrically tunable chemical reactions. We demonstrate repetitive precipitation and dissolution of metal phosphates in a pore through manipulations of cation flow by transmembrane voltage. Under negative voltages, precipitates grow to reduce ionic current by occluding the nanopore, while inverting the voltage polarity dissolves the phosphate compounds reopening the pore to ionic flux. Reversible actuation of these physicochemical processes creates a nanofluidic diode of rectification ratio exceeding 40000. The dynamic nature of the in-pore reactions also facilitates a memristor of sub-nanowatt power consumption. Leveraging chemical degrees of freedom, the present method may be useful for creating iontronic circuits of tunable characteristics toward neuromorphic systems.
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7,794 members
Yuquan Lu
  • Department of Social Medicine
Masae Kuboniwa
  • Department of Preventive Dentistry
Luca Baiotti
  • International College and Graduate School of Science
Nayuta Takemori
  • Center for Quantum Information and Quantum Biology
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Osaka, Japan