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en: Microvibration stimuli causes localized depolymerization of actin cytoskeleton of osteoblasts around the nucleus

en: Reports have indicated that microvibration stimulation activates bone remodeling and promotes bone formation. However, the mechanism by which microvibration stimulation facilitates bone formation remains incompletely understood, and it is unclear how osteoblasts sense microvibration stimulation. In this study, we focused on the actin cytoskeleton, a key component of the mechanosensing mechanism. The actin cytoskeleton plays a role in mechanotransduction by physically transmitting mechanical stimuli from the cell surface to the interior of the cell. It is also known that actin stress fibers undergo structural remodeling in response to changes in the tension acting upon them. We investigated the structural remodeling of the actin cytoskeleton in osteoblasts subjected to microvibration stimulation using fixed cells and fluorescence staining of actin. Our results revealed that in osteoblasts subjected to microvibration, local actin depolymerization occurred around the cell nucleus for approximately 3 hours following the application of vibration. Furthermore, by 10 hours post-vibration, the actin cytoskeleton had repolymerized and returned to its pre-vibration state. These findings suggest that microvibration stimulation is transmitted from focal adhesions to the actin cytoskeleton surrounding the cell nucleus and then further into the cell.

en: Journal of Biomechanical Science and Engineering


en: Raman Spectroscopic Evaluation of Composition of Matrix Synthesized by Osteoblasts under Microvibration Stimulation

en: Advanced Biomedical Engineering

ja: Advanced Biomedical Engineering


en: Evaluation of the basic designs of a micro device that provides vibration stimulation to cells

en: Journal of Robotics and Mechatronics

ja: Journal of Robotics and Mechatronics


en: Difference in the osteoblastic calcium signaling response between compression and stretching mechanical stimuli


en: Cyclical Stretching Induces Excess Intracellular Ca2+ Influx in Human Keloid-Derived Fibroblasts In Vitro

en: The incidence of keloids is higher in the case of darker skin. It is more common in the parts exposed to stretching (thorax, abdomen, and joints). Cyclical stretching reportedly induced each Ca2+ spike through differential mechanosensitive channels in human synovial and dermal fibroblasts. Therefore, the authors hypothesized that cyclical stretching also induces a specific Ca2+ spike in keloid-derived fibroblasts. This in vitro study compared the intracellular calcium dynamics induced by cyclical stretching between control (human dermal fibroblasts) and keloid (human keloid-derived fibroblasts) groups. Each group was exposed to two-dimensional stretch using an originally developed stretch microdevice. Intracellular Ca2+ was observed for 5 minutes, including 30 seconds of baseline, under a fluorescent confocal laser microscope. The intracellular Ca2+ concentration was evaluated every 0.5 second using the fluorescence intensity ratio. A positive cellular response was defined as a rise of the ratio by greater than or equal to 20%. The normal response cutoff value was determined by receiver operating characteristic analysis. The keloid groups were significantly more responsive than the control groups (15.7% versus 8.2%; P = 0.029). In the cellular response-positive cells, the keloid groups reached significantly higher intracellular Ca2+ concentration peaks than the control groups (2.20 versus 1.26; P = 0.0022). The cutoff value was 1.77, and 10.4% of the keloid-derived fibroblasts exhibited a hyper-Ca2+ spike above the normal range. Keloid-derived fibroblasts with a hyper-Ca2+ spike might constitute a keloid-specific subpopulation. Hereafter, the authors will study whether the normalization of excessive intracellular Ca2+ concentration leads to keloid treatment in vivo. This study result provided a clue to the onset mechanism of keloids, which the authors hope will lead to the development of new therapy in the future.

en: Plastic and Reconstructive Surgery

ja: Plastic and Reconstructive Surgery


en: Quantitative evaluation of both histological and mechanical recovery in injured tendons using Fourier-transform second-harmonic-generation microscopy

en: IEEE Journal of Selected Topics in Quantum Electronics


en: Development of micro mechanical device having two-dimensional array of micro chambers for cell stretching

en: This paper presents a novel cell stretching micro device having two-dimensional array of micro chambers. It enables an in situ time-lapse observation of stretched cell by using an optical microscope with high measurement efficiency. The presented device consists of a cell culture dish and the array of micro chambers made of silicone elastomer and extension structures made of photocurable resin, and is fabricated with MEMS technology. The fabrication process of the thin micro chamber array combines photoresist mold and lift-off process based on conventional photolithography. The fabricated device has 134micro chambers in 5μm or less thickness. It was demonstrated that the fabricated micro device could be used to make in-situ time-lapse observation of cell responses to stretching under optical microscopy. In addition, the influence of the chamber thickness to the quality of the microscope image observed was evaluated. It is confirmed that the proposed device having two-dimensional array of the thin micro chambers makes it possible to observe cell response for stretch stimuli with high quality and efficiency.

en: Biomedical Microdevices

ja: Biomedical Microdevices


en: In situ observation and measurement of actin stress fiber deformation in stretched osteoblast like cell

en: Advances in Bioscience and Biotechnology


en: Development of cylindrical reactive ion etching technology for fabricating tubular microstructures

en: Journal of Micromechanics and Microengineering


en: Difference in Road Surface Recognition by Disease and Grades of The Low Vision

en: In our previous studies, Lateral Bands that were placed in both side of Tactile Walking Surface Indicators, and the result of clinical testing of Lareral Bands indicated the effectiveness for the Low Vison to show walking way. In this paper, relation between visibility and miss-recognition was studied from the different point of view in date of the previous study. Influence both by the difference in visual impairment and the difference in grades of disability was also studied. As the results, it was suggested that 30% of luminance contrast was the optimum value for both keeping visibility of Tactile Walking Surface Indicators with Lateral Bands and producing no miss-recognition.

ja: 我々の以前の研究で，視覚障害者誘導用ブロックの両側に置かれた側帯と側帯の医学的な実験結果は視覚障害者が道を歩いていて見つけるために有効であることが示された．本論文では，視認性と誤識別の関係を前の研究のデータを異なった観点から検証した．視覚障害者の症状の違いと等級の違いによる影響も検証した．結果として，30%の輝度コントラストが側帯と製造された点字ブロックの視認に誤識別しないことを担保するための最適値であることが示された．

en: Assistive Technology Research Series

ja: Assistive Technology Research Series


en: Verification of LED Blocks used at Crosswalk Entrances for Persons with Visually Impairment

en: The eyesight of a person with low visual capacity (LV) might decrease remarkably under low-light conditions such as the morning, evening, and nighttime, decreasing their opportunities to go out. Research and development underway to ensure safe walking for LVs examined a walking guidance system in which LED blocks are embedded into the road at edges of warning blocks installed at crosswalk entrances. The LED block can be detected with the LVs residual vision. The detectability of this LED block was evaluated by subjective experiments performed by visually impaired and blind persons.

ja: ロービジョン者の中には，朝夕や夜間などの低照度環境下において視力による視認性が著しく低下する場合がある．このことが，ロービジョン者の外出の機会の減少させる一因となっている．視覚障害者の安全な歩行を確保するため，視覚障害者誘導支援システムに関する様々な研究・開発が行われている．本研究では，LED発光ブロックを路面に埋め込む歩行誘導システムについて検討した．横断歩道口用発光ブロックを横断歩道口の注意喚起ブロックの端に設置した．この発光ブロックはロービジョン者にとっては，残存視力で知覚することができる．この発光ブロックの知覚に関する性能特性を被験者実験によって評価した．被験者実験はロービジョン者と盲人によって実施した．


en: Research on the Occupational Ability Evaluation Technique in the Group Work of Intellectually/Mentally Handicapped Persons by MODAPTS Method

en: The first objective is to analyze the characteristics of the intellectually/mentally disabled more deeply in order to help the government and companies to understand them and the employment rate to increase. The second objective is to review the work evaluation method of the intellually/mentally disabled anew through this evaluation in order to trigger the research on the intellectually/mentally disabled to be activated. The result of the verification performed by this research has showed that the success or failure in a continuous company employment is more significantly related to the factors of ``surrounding healthy persons'' which are external factors than the factors arising from the disability of a disabled person.

ja: 本研究の第一の目的は，政府と会社が彼らを理解し就職率が増加することより深く支援するために，知的/精神障害者の特性を分析することである．第二の目的は，知的/精神障害者が活動的になることを研究が引き金になってこの評価を新たに通して，知的/精神障害者の作業評価方法を見直すことである．本研究の検証の結果，会社の雇用の阻害要因が障害者の障害から起こる要素より外部の要素である「強周囲の健康な人」の要素にかなり関連するのを示した．


en: Continuity of Tactile Walking Surface Indicators and Audible Pedestrian Signals at Crosswalks

en: Crossing an intersection is one of the most risky actions for a visually impaired person. A visually impaired pedestrian is guided to the crosswalk entrance by the tactile walking surface indicators "TWSIs". It is then important that he/she safely and smoothly cross the intersection using the audible pedestrian signal. However, neither connectivity nor the continuity between the TWSIs and the audible pedestrian signal travel support systems has been verified. The purpose of this research is to verify this connectivity and continuity. It should be possible to acquire basic scientific data for developing guidelines from the findings of this research.

ja: 視覚障害者が交差点を横断するのは，最も危険な行動の1つである．視覚障害を持つ歩行者は視覚障害者誘導用ブロック「TWSIs」によって横断歩道入り口に誘導される．視覚障害者が歩行者用音響信号を利用して安全にかつ円滑に交差点を横断することが重要です．しかしながら，TWSIsと音響式歩行者信号との歩行支援システム間の接続性や連続性が確保させていない．本研究の目的は，この接続性と連続性について確かめることある．本研究の知見から指針設計のための基本的なの科学的データを取得することが可能となる．


en: Myosin-II-mediated directional migration of dictyostelium cells in response to cyclic stretching of substratum

en: Living cells are constantly subjected to various mechanical stimulations, such as shear flow, osmotic pressure, and hardness of substratum. They must sense the mechanical aspects of their environment and respond appropriately for proper cell function. Cells adhering to substrata must receive and respond to mechanical stimuli from the substrata to decide their shape and/or migrating direction. In response to cyclic stretching of the elastic substratum, intracellular stress fibers in fibroblasts and endothelial, osteosarcoma, and smooth muscle cells are rearranged perpendicular to the stretching direction, and the shape of those cells becomes extended in this new direction. In the case of migrating Dictyostelium cells, cyclic stretching regulates the direction of migration, and not the shape, of the cell. The cells migrate in a direction perpendicular to that of the stretching. However, the molecular mechanisms that induce the directional migration remain unknown. Here, using a microstretching device, we recorded green fluorescent protein (GFP)-myosin-II dynamics in Dictyostelium cells on an elastic substratum under cyclic stretching. Repeated stretching induced myosin II localization equally on both stretching sides in the cells. Although myosin-II-null cells migrated randomly, myosin-II-null cells expressing a variant of myosin II that cannot hydrolyze ATP migrated perpendicular to the stretching. These results indicate that Dictyostelium cells accumulate myosin II at the portion of the cell where a large strain is received and migrate in a direction other than that of the portion where myosin II accumulated. This polarity generation for migration does not require the contraction of actomyosin.

en: Biophysical Journal

ja: Biophysical Journal


en: Mis-recognition of Road Surface by The Low Vision

en: The low vision sometimes miss-recognize road surface as holes or ditches. The purpose of our research is to find parameters of road surface that causes this kind of miss-recognition. As the preliminary result of our research, this paper describes how the low vision recognizes road surface incorrectly. Fifty-nine low vision persons were participated as subjects in these experiments. Visibility of road surface's line that have different parameters in width, luminance contrast, and illumination was experimentally studied. One of the three experiment, eight lines that have different parameters respectively were showed to a subject at a time. The lines were arranged in ascending order. At the end of each experiment, comments from a subject were obtained.

ja: 弱視者は時々路面を穴や溝として誤識別する．この場合の誤識別に起因する路面の要因を見つけることが本研究の目的である．本研究の予備結果として，本論文は弱視者がどのように路面を誤認識するかを説明する．弱視者59名を被験者として実験に参加した．幅，輝度比，および照明の異なったパラメータの路面の線の視認性を実験で検証を行った．三つの内の一つの実験では，被験者にそれぞれ異なったパラメータを持った8本の線を一度に見てもらう．線は昇降順に配置されている．それぞれの実験の終わりに，被験者からの回答を得た．


en: An evaluation of tactile walking surface indicators for the visually impaired

en: Tactile Walking Surface Indicators (TWSIs) are a vital walking aid for the visually impaired, especially those with complete blind person, but the blocks are still not available on all walkways. This study was performed with visually inpaired person to determine to what degree TWSI (in particular, blocks with raised parts to indicate caution) contribute to direction determination, with the goal of improving the utility of TWSIs. By comparing drift after 5m of straight line travel, significant differences were seen between the existence and nonexistence of border elevation for both square and zigzag patterns, confirming that determining direction when using square patterns over zigzag patterns.

ja: 視覚障害者誘導用ブロック(TWSIs)は視覚障害者，特に全盲者のための重要な歩行支援用品である．しかし，点字ブロックがすべての歩道で有効ではない．本研究はTWSI(特に，注意喚起ブロック)が方向の決定に貢献する割合を決定するため視覚障害者で検証を行った．TWSIsの形状を改善することが目的である．直線を5m歩行した後，その偏軌を比較することによって，正方配列と千鳥配列の方向提示性能の違いがあるかの検証を行う．方向提示性能は千鳥配列より正方配列が有意であることが確認できた．


en: Research on continuity among assistive devices for personal mobility of visually impaired persons around crossings

en: Tactile walking-surface indicators (TWSIs) are necessary for visually impaired persons to walk independently. Audible pedestrian signals are also necessary for them to cross intersections. TWSIs support approaching the intersection, and audible pedestrian signals support crossing the intersection. However, the support of audible pedestrian signals may not necessarily be related to the support of the TWSIs. This research sought to verify how visually impaired persons are guided by different positions where the audible pedestrian signals are set up.

ja: 視覚障害者誘導用ブロックは視覚障害者の単独歩行には重要である．音響式方向者信号は同様に交差点の横断するために重要である．点字ブロックは交差点までを誘導し，音響式方向者信号機は交差点を横断することを支援する．しかしながら，音響式歩行者信号機の支援は点字ブロックの支援と連携をとっていないことがある．本研究では，音響式歩行者信号機を設置される場所の異なる位置で視覚障害者が如何に誘導されるかを検証することである．