Ritsumeikan UniversityShiga

College of Science and, Japan

Ritsumeikan UniversityShiga

College of Science and, Japan

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Zhu J.,University of Fribourg | Zhu J.,Geneva Lab | Bailly A.,University of Fribourg | Bailly A.,University of Zürich | And 29 more authors.
Plant Cell | Year: 2016

Plant growth and architecture is regulated by the polar distribution of the hormone auxin. Polarity and flexibility of this process is provided by constant cycling of auxin transporter vesicles along actin filaments, coordinated by a positive auxinactin feedback loop. Both polar auxin transport and vesicle cycling are inhibited by synthetic auxin transport inhibitors, such as 1-Nnaphthylphthalamic acid (NPA), counteracting the effect of auxin; however, underlying targets and mechanisms are unclear. Using NMR, we map the NPA binding surface on the Arabidopsis thaliana ABCB chaperone TWISTED DWARF1 (TWD1).We identify ACTIN7 as a relevant, although likely indirect, TWD1 interactor, and show TWD1-dependent regulation of actin filament organization and dynamics and that TWD1 is required for NPA-mediated actin cytoskeleton remodeling. The TWD1-ACTIN7 axis controls plasma membrane presence of efflux transporters, and as a consequence act7 and twd1 share developmental and physiological phenotypes indicative of defects in auxin transport. These can be phenocopied by NPA treatment or by chemical actin (de)stabilization. We provide evidence that TWD1 determines downstreamlocations of auxin efflux transporters by adjusting actin filament debundling and dynamizing processes and mediating NPA action on the latter. This function appears to be evolutionary conserved since TWD1 expression in budding yeast alters actin polarization and cell polarity and provides NPA sensitivity. © 2016 American Society of Plant Biologists. All rights reserved.

Dau V.T.,Sumitomo Chemical | Dinh T.X.,Ritsumeikan UniversityShiga | Bui T.T.,Vietnam National University, Hanoi | Terebessy T.,Atrium Innovation Ltd.
Flow Measurement and Instrumentation | Year: 2016

In this paper, we present a study on a jet flow, assisted by low net charge ion wind from bipolar corona discharge setup. The ion wind is simultaneously generated from both positive and negative electrodes placed in parallel, adding momentum to the bulk flow directed alongside the electrodes and focused in the middle of interelectrode space. The electrodes are connected to a single battery-operated power source in a symmetrical arrangement, where the electrode creating charged ions of one polarity also serves as the reference electrode to establish the electric field required for ion creation by the opposite electrode, and vice versa. Multiphysics numerical simulation is carried out with programmable open source OpenFOAM, where the measured current-voltage is applied as a boundary condition to simulate the electrohydrodynamics flow. The jet flow inside the device is verified by hotwire anemometry using hotwires embedded within the device, with the measured values in good agreement with simulation. The corona discharge helped to focus the jet and increased the flow peak velocity from 1.41 m/s to 2.42 m/s with only 27.1 mW of consumed discharge power. The device is robust, ready-to-use and minimal in cost. In addition, as the oppositely charged corona flows are self-neutralized, the generated air flow remains neutral and therefore does not attach to a particular target, which expands the application range. These are important features, which can contribute to the development of multi-axis fluidic inertial sensors, fluidic amplifiers, micro blowers, gas mixing, coupling and analysis with space constraints and/or where neutralized discharge process is required, such as circulatory flow heat transfer or the formation of low charged aerosol for inhalation and charged particle deposition. © 2016 Elsevier Ltd

Yasuda H.,Ritsumeikan UniversityShiga | Sakaue Y.,Ritsumeikan UniversityShiga | Tanaka M.,Osaka Dental University | Matsushima M.,Kurary CO. | And 4 more authors.
Transactions of Japanese Society for Medical and Biological Engineering | Year: 2014

Chewing is thought to be important for normal swallowing, because it fixes the human mandible on proper place. When fulcrum of tongue movement vanishes, it becomes difficult to roll food bolus and saliva into pharynx by tongue. The purpose of this study is to develop a new swallowing measurement system focused on the movement of prominentia laryngea and mandible to estimate the swallowing mechanism. In our measurement system, a flexible polymer curvature sensor (FPCS), that converts its bending curvature into voltage, was used to measure the movement of prominentia laryngea and mandible during swallowing. FPCSs were attached on prominentia laryngea and bulging of masseter in the vicinity of mandible. The waveforms of FPCSs changed according to swallowing. Results suggest that the swallowing test focusing on movement of prominentia laryngea and mandible is possible. © 2014, Japan Soc. of Med. Electronics and Biol. Engineering. All rights reserved.

Ogoh S.,Toyo University | Sorensen H.,Copenhagen University | Hirasawa A.,Kyorin University | Sasaki H.,Toyo University | And 4 more authors.
Experimental Physiology | Year: 2016

New Findings: What is the central question of this study? Dynamic cerebral autoregulation (CA) is impaired by sympathetic blockade, and the external carotid artery (ECA) vascular bed may prevent adequate internal carotid artery blood flow. We examined whether α1-receptor blockade-induced attenuation of dynamic CA is related to reduced ECA vasoconstriction. What is the main finding and its importance? α1-Receptor blockade attenuated dynamic CA, but in contrast to our hypothesis did not affect the ECA blood flow response to acute hypotension. These findings suggest that the recovery of cerebral blood flow during acute hypotension is unrelated to vasoconstriction within the ECA territory. External carotid artery (ECA) vasoconstriction may defend internal carotid artery (ICA) blood flow during acute hypotension. We hypothesized that the α1-receptor blockade-induced delay in ICA recovery to the baseline level from acute hypoperfusion is related to attenuated ECA vasoconstriction. The ICA and ECA blood flow were determined by duplex ultrasound during thigh-cuff release-induced acute hypotension while the α1-receptor blocker prazosin [1 mg (20 kg)−1] was administered to nine seated young healthy men. Both ICA (mean ± SD; by 17 ± 8%, P = 0.005) and ECA (by 37 ± 15%, P < 0.001) blood flow decreased immediately after occluded thigh-cuff release, with a more rapid ICA blood flow recovery to the baseline level (9 ± 5 s) than for the ECA blood flow (17 ± 5 s; P = 0.019). The ICA blood flow recovery from hypoperfusion was delayed with prazosin (17 ± 4 s versus control 9 ± 5 s, P = 0.006), whereas ECA recovery remained unchanged (P = 0.313) despite a similar reduction in mean arterial pressure (−20 ± 4 mmHg versus control −23 ± 7 mmHg, P = 0.148). These findings suggest that α1-receptor blockade-induced attenuation of the ICA blood flow response to acute hypotension is unrelated to the reduction in ECA blood flow. The sympathetic nervous system via the ECA vascular bed does not contribute to dynamic CA during acute hypotension. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society

Imai T.,Kyoto University | Kurihara T.,Kyoto University | Esaki N.,Kyoto University | Mihara H.M.,Ritsumeikan UniversityShiga
Bioscience, Biotechnology and Biochemistry | Year: 2014

Selenite is a selenium source for selenoprotein biosynthesis in mammalian cells. Although previous studies have suggested the involvement of glutathione (GSH) and/or thioredoxin reductase in selenite metabolism, intracellular selenite metabolism remains largely unknown. Here, we report that GSH depletion did not affect the amount of selenoprotein in Hepa 1-6 cells, suggesting that GSH does not play a central role in the reduction of selenite in selenoprotein biosynthesis. On the other hand, we found that GSH is involved in the efflux of lowmolecular-weight selenium compounds from cells, presumably via the formation of selenodiglutathione. Moreover, selenite inhibited the efflux of a fluorescent bimane-GS conjugate that is mediated by ATPdependent multidrug-resistant proteins, implying the existence of an active transporter for selenodiglutathione. This is the first report demonstrating that GSH plays a role in selenium excretion from cells by forming a GSH-conjugate, which may contribute to the distribution, detoxification, and homeostasis of selenium in the body. © 2014 Japan Society for Bioscience, Biotechnology, and Agrochemistry.

Konno Y.,Ritsumeikan UniversityShiga | Han X.-H.,Ritsumeikan UniversityShiga | Lin L.,Zhejiang University | Hu H.,Zhejiang UniversityZhejiang | And 4 more authors.
Smart Innovation, Systems and Technologies | Year: 2016

Automatic liver lesion enhancement and detection has an essential role for the computer-aided diagnosis of liver tumor in CT volume data. This paper proposes a novel lesion enhancement strategy using Bayesian framework by combining the lesion probabilities based on an adaptive non-parametric model with the processed test volume and the constructed common non-lesion models with prepared liver database. Due to the large variation of different lesion tissues, it is difficult to obtain the common lesion prototypes from liver volumes, and thus this paper investigates a lesion-training-data free strategy by only constructing the healthy liver and vessel prototypes using local patches, which can be extracted from any slice of the test liver volume, and is also easy to prepare the common training non-lesion samples for all volumes. With the healthy liver and vessel prototypes from the test volume, an adaptive non-parametric model is constructed for estimating the lesion possibility, which is considered as the pixel likelihood to lesion region; the common model constructed using the pre-prepared liver database is used to estimate the pixel probability, which is defined as prior knowledge due to the used unvaried model. Finally, the posterior probabilities based on Bayesian theory are achieved for enhancing lesion regions. Experimental results validate that the proposed framework can not only detect almost small lesion regions but also greatly reduce falsely detect regions. © Springer International Publishing Switzerland 2016.

Fujii R.,Ritsumeikan UniversityShiga | Tateyama T.,Ritsumeikan UniversityShiga | Kitrungrotsakul T.,Ritsumeikan UniversityShiga | Tanaka S.,Ritsumeikan UniversityShiga | Chen Y.-W.,Zhejiang University
Smart Innovation, Systems and Technologies | Year: 2016

The purpose of this study is to construct a system for surgical assistance by touchless interactions. In the clinical site, surgeons usually need to use some contacting devices to display or visualize medical images and check the anatomic information of the patient. However, after operating the visualization device, re-sterilization is necessary in order to maintain hygiene. Though some touchless surgery support systems using Kinect have been developed, their functions are not enough for surgical support. In this paper, we develop a new system, which can visualize 3D medical image by simple touchless single-handed interactions. © Springer International Publishing Switzerland 2016.

Dau V.T.,Sumitomo Chemical | Bui T.T.,Japan National Institute of Advanced Industrial Science and Technology | Dinh T.X.,Ritsumeikan UniversityShiga | Terebessy T.,Atrium Innovation Ltd.
Sensors and Actuators, A: Physical | Year: 2016

We present a pressure sensing unit based on a unique corona discharge setup using symmetrical electrode arrangement with simultaneous positive and negative corona generation. The device generates stable corona discharge and enables reliable air pressure measurement in the range of 80-105 kPa, tested with five prototypes. The current-voltage characteristics of bipolar discharge system is analyzed in general form and three governing parameters, namely electrode geometry, electrode distance and discharge current, are studied in relation with absolute pressure. The sensors are driven with constant discharge current as low as 1 μA. The measured sensitivity is in good agreement with theoretical prediction and the sensor stability has been confirmed with 20-h continuous test without sensitivity deterioration. The sensitivity does not depend on the tested temperature range and its variation between devices is small, approximately ±3.0%. The advantage of the proposed system compared with similar corona-based constructions is its stable operation at low current with low power consumption and minimum electrode deterioration, which provides a cost effective and reliable solution. & copy;2015 Elsevier B.V. All rights reserved.

Fujie S.,Ritsumeikan UniversityShiga | Hasegawa N.,Ritsumeikan UniversityShiga | Sato K.,Ritsumeikan UniversityShiga | Fujita S.,Ritsumeikan UniversityShiga | And 3 more authors.
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2015

Aging-induced arterial stiffening is reduced by aerobic exercise training, and elevated production of nitric oxide (NO) participates in this effect. Adropin is a regulator of endothelial NO synthase and NO release, and circulating adropin level decreases with age. However, the effect of habitual aerobic exercise on circulating adropin levels in healthy middleaged and older adults remains unclear. We sought to determine whether serum adropin level is associated with exercise training-induced changes in arterial stiffness. First, in a cross-sectional study, we investigated the association between serum adropin level and both arterial stiffness and cardiorespiratory fitness in 80 healthy middle-aged and older subjects (65.6_0.9 yr). Second, in an intervention study, we examined the effects of 8-wk aerobic exercise training on serum adropin level and arterial stiffness in 40 healthy middle-aged and older subjects (67.3 ± 1.0 yr) divided into two groups: aerobic exercise training and sedentary controls. In the cross-sectional study, serum adropin level was negatively correlated with carotid _-stiffness (r = –0.437, P < 0.001) and positively correlated with plasma NOx level (r = 0.493, P < 0.001) and cardiorespiratory fitness (r = 0.457, P < 0.001). Serum adropin levels were elevated after the 8-wk aerobic exercise training intervention, and training-induced changes in serum adropin level were correlated with traininginduced changes in carotid β-stiffness (r = –0.399, P < 0.05) and plasma NOx level (r = 0.623, P < 0.001). Thus the increase in adropin may participate in the exercise-induced reduction of arterial stiffness. © 2015 the American Physiological Society.

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