A5012197403- Cellular Mechanics and Interactions
- Material Dynamics and Properties
- Corrosion Behavior and Inhibition
- Advanced Thermodynamics and Statistical Mechanics
- Force Microscopy Techniques and Applications
- Microfluidic and Bio-sensing Technologies
- Hydrogen embrittlement and corrosion behaviors in metals
- Non-Destructive Testing Techniques
- Surfactants and Colloidal Systems
- Microtubule and mitosis dynamics
- Micro and Nano Robotics
- Blood properties and coagulation
- Electrostatics and Colloid Interactions
- Concrete Corrosion and Durability
- Cancer Diagnosis and Treatment
- Proteoglycans and glycosaminoglycans research
- Electrowetting and Microfluidic Technologies
- 3D Printing in Biomedical Research
- Fatigue and fracture mechanics
- Neuroblastoma Research and Treatments
- Semiconductor materials and devices
- Metal Alloys Wear and Properties
- Protein Structure and Dynamics
- Tannin, Tannase and Anticancer Activities
- Orbital Angular Momentum in Optics
Kyushu University
2014-2025
Okayama University
2024
Aichi Medical University
2015-2024
JFE Holdings (Japan)
2006-2022
Okayama Rosai Hospital
2021-2022
Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine
2019
Sophia University
2019
Tokyo Institute of Technology
2018
Keihin (Japan)
2018
Centre National de la Recherche Scientifique
2014
Cells both actively generate and sensitively react to forces through their mechanical framework, the cytoskeleton, which is a nonequilibrium composite material including polymers motor proteins. We measured dynamics properties of simple three-component model system consisting myosin II, actin filaments, cross-linkers. In this system, stresses arising from activity controlled cytoskeletal network mechanics, increasing stiffness by factor nearly 100 qualitatively changing viscoelastic response...
Quantitatively measuring the mechanical properties of soft matter over a wide range length and time scales, especially if sample is as complex typical biological materials, remains challenging. Living cells present further complication because forces are generated within these nonequilibrium materials that can change material properties. We have here developed high-bandwidth techniques for active one- two-particle microrheology to tackle issues. By combining micromanipulation probe particles...
Theileria orientalis is one of the benign species that widely distributed in Japan and sometimes responsible for serious economic losses livestock industry. In present study, we surveyed current status T. infection grazing cattle eastern areas Hokkaido (Taiki, Otofuke, Shintoku, Shin-Hidaka districts) using molecular methods, as well traditional diagnosis. The genes encoding major piroplasm surface protein (MPSP) p23 were identified highly detectable polymerase chain reaction (PCR). Results...
Dynamic networks designed to model the cell cytoskeleton can be reconstituted from filamentous actin, motor protein myosin and a permanent cross-linker. They are driven out of equilibrium when molecular motors active. This gives rise athermal fluctuations that recorded by tracking probe particles dispersed in network. We have here probed such "active gels" using video microrheology. measured full distribution displacements, also known as van Hove correlation function. The dominant influence...
Nonequilibrium energetics of single molecule translational motor kinesin was investigated by measuring heat dissipation from the violation fluctuation-response relation a probe attached to using optical tweezers. The sum and work did not amount input free energy change, indicating large hidden exists. Possible sources were explored analyzing Langevin dynamics probe, which incorporates two-state Markov stepper as model. We conclude that internal is dominant.
Abstract Physiological processes in cells are performed efficiently without getting jammed although cytoplasm is highly crowded with various macromolecules. Elucidating the physical machinery challenging because interior of a cell so complex and driven far from equilibrium by metabolic activities. Here, we studied mechanics vitro living using particle-tracking manipulation technique. The molecular crowding effect on cytoplasmic was selectively preparing simple models which both metabolism...
Feedback-tracking microrheology, developed to study nonequilibrium mechanics of active materials, revealed glassy cell dynamics.
Active microrheology was conducted in living cells by applying an optical-trapping force to vigorously fluctuating tracer beads with feedback-tracking technology. The complex shear modulus G(ω)=G′(ω)−iG″(ω) measured HeLa epithelial-like confluent monolayer. We found that G(ω)∝(−iω)1/2 over a wide range of frequencies (1 Hz < ω/2π 10 kHz). Actin disruption and cell-cycle progression from G1 S G2 phases only had limited effect on G(ω) cells. On the other hand, be dependent cell metabolism;...
Cells actively probe mechanical properties of their environment by exerting internally generated forces. The response they encounter profoundly affects behavior. Here we measure in a simple geometry the forces cell exerts suspended two optical traps. Our assay quantifies both overall force and fraction that transmitted to environment. Mimicking environments varying stiffness adjusting strength traps, found transmission is highly dependent on external compliance. This suggests calibration...
The movement of single kinesin molecules was observed while applying noisy external forces that mimic intracellular active fluctuations. We found accelerates under noise, especially when a large hindering load is added. behavior quantitatively conformed to theoretical model describes the with simple two-state reactions. universality kinetic theory suggests enzymes share similar noise-induced acceleration mechanism, i.e., fluctuations in cells are not just noise but utilized promote various...
We show the intracellular upregulation of NO production after mechanical stimulation, an essential chemical signal in bone remodeling. This is done real time using fluorescent chromophore DAR-4M AM. Differences cellular response to stimulation different regions a single cell were observed.Osteocytes are most abundant cells that believed be mechanosensors bone, responding stresses interstitial fluid flow through canaliculi. Under load, signals such as play key role activity...
We provide a direct experimental test of the fluctuation-dissipation theorem (FDT) in an aging colloidal glass. The use combined active and passive microrheology allows us to independently measure both correlation response functions this nonequilibrium situation. Contrary previous reports, we find no deviations from FDT over several decades frequency (1 Hz--10 kHz) for all times. In addition, two distinct viscoelastic contributions glass, including nearly elastic at low frequencies that...
Theileria orientalis is a benign protozoan species that widely distributed in Japan, yet sometimes causes serious economic losses the livestock industry. In this study, we conducted molecular survey based on genes encoding major piroplasm surface protein (MPSP) and p23 for T. detected cattle grazing southern areas of consisting 2 farms Kumamoto prefecture (Aso Kuma districts) 3 Okinawa (Ishigaki, Iriomote, Yonaguni Islands). High prevalence rates infection were shown all populations using...
In a two-part series of papers, the galvanic corrosion behavior sensitized aluminum alloy (AA)5083-H131 (UNS A95083) when coupled with AISI 4340 G43400) steel was studied experimentally and computationally, an emphasis on atmospheric conditions. Part 1, electrochemical kinetics AA5083-H131 in salt solutions relevance to were determined, including influence degree sensitization (DoS), potential, sodium chloride (NaCl) concentration context intergranular (IGC) propagation. More severe IGC seen...
We developed a technique of picking up the liquid surface in noncontact manner by cw-laser radiation. The momentum change light at laser transmission through air-liquid interface appears as radiation pressure, which deforms into shape determined balance between Laplace force curved and pressure. displacement is inversely proportional to tension, was measured an optical probe. dynamic response deformation theoretically derived under periodical modulation experimentally observed spectra were...
Many cells cover themselves with a multifunctional polymer coat, the pericellular matrix (PCM), to mediate mechanical interactions environment. A particular PCM, endothelial glycocalyx (EG), is formed by vascular at their luminal side, forming interface between flowing blood and cell layer. The glycosaminoglycan (GAG) hyaluronan (HA) involved in main functions of EG, mechanotransduction fluid shear stress molecular sieving. HA, due its length, only GAG EG or any other PCM able form an...
We report measurements of the frequency-dependent shear moduli aging colloidal systems that evolve from a purely low-viscosity liquid to predominantly elastic glass or gel. Using microrheology, we measure local complex modulus ${G}^{*}(\ensuremath{\omega})$ over very wide range frequencies (from $1\phantom{\rule{0.3em}{0ex}}\mathrm{Hz}\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}100\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$). The combined use one- and two-particle...
We have directly observed short-time stress propagation in viscoelastic fluids using two optically trapped particles and a fast interferometric particle-tracking technique. done this both by recording correlations the thermal motion of measuring response one particle to actively oscillated second particle. Both methods detect vortexlike flow patterns associated with fluids. This inertial vortex propagates diffusively for simple liquids, while solutions pattern spreads superdiffusively,...
Many cells express a membrane-coupled external mechanical layer, the pericellular matrix (PCM), which often contains long-chain polymers. Its role and properties are not entirely known, but its functions believed to include physical protection, mechanosensing, chemical signalling or lubrication. The viscoelastic response of PCM, with polysaccharides as main structural components, is therefore crucial for understanding function. We have here applied microrheology, based on optically trapped...