Selectable diffusion direction with topologically protected edge modes

Topological insulators provide great potentials to control diffusion phenomena as well as waves. Here, we show that the direction of thermal diffusion can be selected by the contributions of the topologically protected edge modes via the quantum spin Hall effect in a honeycomb-shaped structure. We demonstrate that when we set our structure to the temperature corresponding to the type of edge mode, the direction of thermal diffusion can be tuned. Moreover, this diffusion system is found to be immune to defects owing to the robustness of topological states. Our work points to exciting new avenues for controlling diffusion phenomena.Comment: 8 pages, 5 figure

Nanomechanical system meets ultra-small, robust, and ultra-low-powered digital communication receiver

Nanomechanical systems offer a versatile platform for both fundamental science and industrial applications. Resonating vibration has been demonstrated to enable an ultrasensitive detection of various physical quantities, with emerging applications including signal processing, biological detection and fundamental tests of quantum mechanics. It has also been shown that the mechanical vibration of a nanoscale cantilever can be used to detect electromagnetic analogue-modulated waves. However, signals obtained with nanoscale receivers are so weak that the data transfer often fails; to the best of our knowledge, no successful practical demonstration has yet been reported. Here, we present the first experimental demonstration of the use of nanomechanical systems for digital data transfer with a digital image. Furthermore, our fabrication method achieved a tiny gap around field emitter of vibrational nano-antenna, which enables the receiver to work with quite a low power consumption, on the order of 10nW

Visualization of walking speed variation-induced synchronized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles with a newly developed gait analysis system

Purpose:To evaluate a newly developed system for dynamic analysis of gait kinematics and muscle activity.Methods:We recruited 10 healthy men into this study. Analyses of three-dimensional motion and wireless surface electromyogram (EMG) were integrated to achieve synchronous measurement. The participants walked continuously for 10 min under two conditions: comfortable and quick pace. Outcome measures were joint angles of the lower limbs determined from reflective markers and myoelectric activity of trunk and lower limbs determined from EMG sensors, comparing comfortable and quick gait pace.Results:Lower limb joint angle was significantly greater at the quick pace (maximum flexion of the hip joint: 4.1°, maximum extension of hip joint: 2.3°, and maximum flexion of the knee joint while standing: 7.4°). The period of maximum flexion of the ankle joint during a walking cycle was 2.5% longer at a quick pace. EMG amplitudes of all trunk muscles significantly increased during the period of support by two legs (cervical paraspinal: 55.1%, latissimus dorsi: 31.3%, and erector spinae: 32.6%). EMG amplitudes of quadriceps, femoral biceps, and tibialis anterior increased significantly by 223%, 60.9%, and 67.4%, respectively, between the periods of heel contact and loading response. EMG amplitude of the gastrocnemius significantly increased by 102% during the heel-off period.Conclusion:Our gait analysis synchronizing three-dimensional motion and wireless surface EMG successfully visualized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles induced by various walking speeds

Flexibly designable wettability gradient for passive control of fluid motion via physical surface modification

Abstract Modified solid surfaces exhibit unique wetting behavior, such as hydrophobicity and hydrophilicity. Such behavior can passively control the fluid flow. In this study, we experimentally demonstrated a wettability-designable cell array consisting of unetched and physically etched surfaces by reactive ion etching on a silicon substrate. The etching process induced a significant surface roughness on the silicon surface. Thus, the unetched and etched surfaces have different wettabilities. By adjusting the ratio between the unetched and etched surface areas, we designed one- and two-dimensional wettability gradients for the fluid channel. Consequently, fine-tuned channels passively realized unidirectional and curved fluid motions. The design of a wettability gradient is crucial for practical and portable systems with integrated fluid channels

Selectable diffusion direction with topologically protected edge modes

Abstract Topological insulators provide great potential to control diffusion phenomena as well as waves. In addition to the thermal localization and robust decay as reported, the topological edge states with higher degree of freedom offers a route to control directional diffusion. Here, we show that the direction of thermal diffusion can be selected by the contributions of the topologically protected edge modes in a honeycomb-shaped structure. Considering the thermal diffusion between the nearest neighboring sites of the honeycomb-shaped unit cells, the cells allow unidirectional heat balance from a macroscopic perspective when we set the structure to the temperature corresponding to the edge mode type. Moreover, this diffusion system is found to be immune to defects owing to the robustness of topological states. Our work points to exciting avenues for controlling diffusion phenomena

Experimental Evaluation of Influence of Stress on Li Chemical Potential and Phase Equilibrium in Two-phase Battery Electrode Materials

We experimentally evaluated the influence of stress on the Li chemical potential (μLi) and phase equilibrium in the two-phase battery electrode materials through the emf measurements while applying a mechanical load. In our measurements, we prepared an electrochemical cell by depositing a thin film of a two-phase electrode material (LiFePO4 or LiCoO2 in the two-phase region) on each of the solid electrolyte surfaces. Then we applied a mechanical load to the electrochemical cell through four-point bending, and the resulting μLi variation in the electrode material was measured as the emf between the two thin films. Our results indicated that μLi in the two-phase electrode materials immediately changed just after loading and then gradually changed while maintaining a constant mechanical load. Besides, the loading and unloading led to the μLi variation in the opposite direction. Such characteristic μLi variations could be explained by considering the change in the phase equilibrium between the two phases, which led to the Li content variation in the two phases and the stress relaxation due to the volume fraction variation of the two phases. Our results can provide valuable insights regarding the influence of stress on the performances of energy storage devices with two-phase electrode materials

Lateral Lumbar Interbody Fusion for Ossification of the Yellow Ligament in the Lumbar Spine: First Reported Case

When ossification of the yellow ligament (OYL) occurs in the lumbar spine and extends to the lateral wall of the spinal canal, facetectomy is required to remove all of the ossified lesion and achieve decompression. Subsequent posterior fixation with interbody fusion will then be necessary to prevent postoperative progression of the ossification and intervertebral instability. The technique of lateral lumbar interbody fusion (LLIF) has recently been introduced. Using this procedure, surgeons can avoid excess blood loss from the extradural venous plexus and detachment of the ossified lesion and the ventral dura mater is avoidable. We present a 55-year-old male patient with OYL at L3/4 and anterior spondylolisthesis of L4 vertebra, with concomitant ossification of the posterior longitudinal ligament, who presented with a severe gait disturbance. He underwent a 2-stage operation without complications: LLIF for L3/4 and L4/5 was performed at the initial surgery, and posterior decompression fixation using pedicle screws from L3 to L5 was performed at the second surgery. His postoperative progress was favorable, and his interbody fusion was deemed successful. Here, we present the first reported case of LLIF for OYL of the lumbar spine. This procedure can be a good option for OYL of the lumbar spine

Establishment of localized irradiation to the kidney and analysis of the radiation sensitivity of the hematopoietic cells in adult medaka (Oryzias latipes)

The kidney is a hematopoetic tissue in medaka (Oryzias latipes) and the hematopietic tissue is sensitive to irradiation. We have been obsereved reduction of hematopietic cells in the kidney by carbon ion beam irradiation up to 2.2 mm in depth of medaka using Takasaki Ion Accelerators for Advanced Application (TIARA) of National institutes for Quantum and Radiological Science and Technology (Nagata.et.al., 2016). In this study, we made further analyses to clarify the radiation response of hematopoetic tissues by peripheral blood cell number and histologically evaluation of the kidney. When the 15 Gy of carbon ion beam was irradiated from the dorsal and ventral side of the kidney, the number of prripheral blood cell was decreased and increased from control 8 days after irradiation, respectively. This result confirmed the histological alterations of our preveous study. Neither the number of the peripheral blood cell nor the heamatopietic cells in the kidney recovered as the control to the 28 days after the irradiation of carbon ion beam from the dorsal side, whereas the histology of the kidney was recovered without increase of the number of the blood cell 28 days after the whole body irradiation by 15 Gy of gamma rays (137Cs). We then shielded medaka with 5-mm-thick acrylic plate with a hole on the position of the kidney to irradiate only kidney area, and irradiated 15 Gy one side or both sides on the kidney from the dorsal side. Seven days after the irradiation, the atrophy and reduction of hematopoietic cells were observed in the irradiated kidney and numbers of the blood cell were fewer in the kidney irradiated group than control. We are now establishing a precise local irradiation system that using heavy-ion microbeam of QST-Takasaki (diameter 250 μm) to analyze the local alterations by the irradiation. It is known that phenylhydrazine (PHZ) cause anemia and anemia may induce proliferation of hematopietic cells. So we used PHZ on medaka as an proliferation activator of the hematopoietic cells. Contrary to our expectation, the number of peripheral blood cells did not decrease 7 days after irradiation. This result suggests that hematopoietic cells become radiation resistant when proliferation was induced.In this study, we established a local irradiation system and clarified the radiation sensitivity of hematopoietic cells in different cell states. These results can contribute to reveal the mechanism of radiation response.第23回小型魚類研究

A Case of Cardiac Arrest during C1 Laminectomy for Irreducible Atlantoaxial Subluxation

We report a case of cardiac arrest, which occurred during C1 laminectomy for irreducible atlantoaxial subluxation, with return of spontaneous circulation (ROSC) upon interruption of the laminectomy. A 60-year-old woman with rheumatoid arthritis presented with neck pain, bilateral finger numbness, and bladder-rectal disturbance. Simple radiograph images showed that the atlantodental interval (ADI) was enlarged to 8 mm, and magnetic resonance imaging revealed severe spinal stenosis at C1. She was diagnosed with cervical spondylotic myelopathy due to atlantoaxial subluxation. Cardiac arrest occurred twice during the C1 laminectomy and occipito-cervical fusion (Occ-C3), and ROSC occurred without any treatment. There was no postoperative worsening of neurological symptoms, and the improvement of sensory and motor palsy was favorable. The pathogenic mechanism was presumed to be trigeminocardiac reflex. Cardiac arrest during upper cervical spine surgery is an important intraoperative complication of which operators should be made aware