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Anat Ratnovsky, Emanuel Kusayev, Sara Naftali
A flexible piezoelectric thin film sensor has been proposed recently in several studies for detection of muscle movements. The objective of this study was to investigate the ability of this sensor to assess skeletal muscle performance and fatigue under isokinetic contractions. Simultaneous noninvasive measurements of muscles activity were done using surface electromyography (EMG) electrodes and two thin film piezoelectric sensors. Measurements were taken from the biceps during slow and fast elbow flexion with and without strong grip, during different weight lifting and from the gastrocnemius during treadmill marching at speeds of 4 and of 10 kph...
January 5, 2018: Technology and Health Care: Official Journal of the European Society for Engineering and Medicine
Wenyan Yang, Wuxiao Han, Huiling Gao, Linlin Zhang, Shuai Wang, Lili Xing, Yan Zhang, Xinyu Xue
As the concentration of different biomarkers in human body fluids are an important parameter of chronic disease, wearable biosensors for in situ analysis of body fluids with high sensitivity, real-time detection, flexibility and biocompatibility have significant potential therapeutic applications. In this paper, a flexible self-powered implantable electronic-skin (e-skin) for in situ body fluids analysis (urea/uric-acid) as a real-time kidney-disease diagnoser has been proposed based on the piezo-enzymatic-reaction coupling process of ZnO nanowire arrays...
January 11, 2018: Nanoscale
Wenzhong Wang, Dengkui Shao, Ling Zhang, Songmei Sun
Oxygen reduction reaction (ORR) for generating H2O2 via green pathways have gained much attention in recent years. Herein, we introduce a piezo-catalytic approach to obtain H2O2 over BiOCl via ORR pathway. The piezoelectric response of BiOCl was directly characterized by piezoresponse force microscope (PFM). The BiOCl exhibits efficient catalytic performance for generating H2O2 (28 µmol/h ) only from O2 and H2O, which is above the average level of H2O2 produced by solar-to-chemical process. A piezo-catalytic mechanism was proposed: with ultrasonic waves, an alternating electric field will be generated over BiOCl, which can drive charge carriers (electrons) to interact with O2 and H2O, then to form H2O2...
January 9, 2018: ChemSusChem
Ayesha Sultana, Priyabrata Sadhukhan, Md Mehebub Alam, Sachindranath Das, Tapas Ranjan Middya, Dipankar Mandal
Methylammonium lead iodide (CH3NH3PbI3) (MAPI) embedded -phase comprising porous polyvinylidene fluoride (PVDF) composite (MPC) films turns to an excellent material for energy harvester and photodetector. MAPI enables to nucleate upto ~ 92 % of electroactive phase in PVDF to make it suitable for piezoelectric based mechanical energy harvesters (PEHs), sensors and actuators. The piezoelectric energy generation from PEH made with MPC film has been demonstrated under simple human finger touch motion. In addition, the feasibility of photosensitive properties of MPC films are manifested under the illumination of non-monochromatic light that also promises the application as organic photodetectors...
January 8, 2018: ACS Applied Materials & Interfaces
Kei Saotome, Swetha E Murthy, Jennifer M Kefauver, Tess Whitwam, Ardem Patapoutian, Andrew B Ward
Piezo1 and Piezo2 are mechanically activated ion channels that mediate touch perception, proprioception and vascular development. Piezos are distinct from other ion channels and their structure remains poorly defined, impeding detailed study of their gating and ion permeation properties. Here we report a high-resolution cryo-electron microscopy structure of the mouse Piezo1 trimer. The detergent-solubilized complex adopts a three-blade propeller shape with a curved transmembrane region containing at least 26 transmembrane helices per protomer...
December 20, 2017: Nature
Yusong R Guo, Roderick MacKinnon
Mechanosensitive ion channels convert external mechanical stimuli into electrochemical signals for critical processes including touch sensation, balance, and cardiovascular regulation. The best understood mechanosensitive channel, MscL, opens a wide pore, which accounts for mechanosensitive gating due to in-plane area expansion. Eukaryotic Piezo channels have a narrow pore and therefore must capture mechanical forces to control gating in another way. We present a cryo-EM structure of mouse Piezo1 in a closed conformation at 3...
December 12, 2017: ELife
Bogdan Mytsyk, Natalya Demyanyshyn, Alessandro Erba, Viktor Shut, Sergey Mozzharov, Yaroslav Kost, Oksana Mys, Rostyslav Vlokh
For the first time, to the best of our knowledge, we have experimentally determined all of the components of the piezo-optic tensor for monoclinic crystals. This has been implemented on a specific example of triglycine sulfate crystals. Based on the results obtained, the complete elasto-optic tensor has been calculated. Acousto-optic figures of merit (AOFMs) have been estimated for the case of acousto-optic interaction occurring in the principal planes of the optical indicatrix ellipsoid and for geometries in which the highest elasto-optic coefficients are involved as effective parameters...
December 1, 2017: Applied Optics
Xianghe Meng, Hao Zhang, Jianmin Song, Xinjian Fan, Lining Sun, Hui Xie
Stiffness matching between the probe and deformed portion of the sample in piezo-drive peak force modulation atomic force microscopy (AFM) limits the modulus measurement range of single probes. Here we develop a magnetic drive peak force modulation AFM to broaden the dynamic range of the probe with direct cantilever excitation. This approach not only successfully drives the softest commercial probe (6 pN nm-1) for mapping extremely soft samples in liquid but also provides an indentation force of hundreds of nanonewtons for stiff samples with a soft probe...
December 5, 2017: Nature Communications
Yonatan Calahorra, Michael Smith, Anuja Datta, Hadas Benisty, Sohini Kar-Narayan
There has been tremendous interest in piezoelectricity at the nanoscale, for example in nanowires and nanofibers where piezoelectric properties may be enhanced or controllably tuned, thus necessitating robust characterization techniques of piezoelectric response in nanomaterials. Piezo-response force microscopy (PFM) is a well-established scanning probe technique routinely used to image piezoelectric/ferroelectric domains in thin films, however, its applicability to nanoscale objects is limited due to the requirement for physical contact with an atomic force microscope (AFM) tip that may cause dislocation or damage, particularly to soft materials, during scanning...
December 1, 2017: Nanoscale
Jason Wu, Michael Young, Amanda H Lewis, Ashley N Martfeld, Breanna Kalmeta, Jörg Grandl
Piezo proteins form mechanically activated ion channels that are responsible for our sense of light touch, proprioception, and vascular blood flow. Upon activation by mechanical stimuli, Piezo channels rapidly inactivate in a voltage-dependent manner through an unknown mechanism. Inactivation of Piezo channels is physiologically important, as it modulates overall mechanical sensitivity, gives rise to frequency filtering of repetitive mechanical stimuli, and is itself the target of numerous human disease-related channelopathies that are not well understood mechanistically...
November 28, 2017: Cell Reports
Tingxin Zhang, Shaopeng Chi, Fan Jiang, Qiancheng Zhao, Bailong Xiao
Piezo proteins are bona fide mammalian mechanotransduction channels for various cell types including endothelial cells. The mouse Piezo1 of 2547 residues forms a three-bladed, propeller-like homo-trimer comprising a central pore-module and three propeller-structures that might serve as mechanotransduction-modules. However, the mechanogating and regulation of Piezo channels remain unclear. Here we identify the sarcoplasmic /endoplasmic-reticulum Ca2+ ATPase (SERCA), including the widely expressed SERCA2, as Piezo interacting proteins...
November 27, 2017: Nature Communications
Yubo Wang, Bailong Xiao
The evolutionarily conserved Piezo family of proteins, including Piezo1 and Piezo2, encodes the long-sought-after mammalian mechanosensitive cation channels that play critical roles in various mechanotransduction processes such as touch, pain, proprioception, vascular development and blood pressure regulation. Mammalian Piezo proteins contain over 2500 amino acids with numerous predicted transmembrane segments, and do not bear sequence homology with any known class of ion channels. Thus, it is imperative, but challenging, to understand how they serve as effective mechanotransducers for converting mechanical force into electrochemical signals...
November 24, 2017: Journal of Physiology
Xinran Tan, Fan Zhu, Chao Wang, Yang Yu, Jian Shi, Xue Qi, Feng Yuan, Jiubin Tan
This study presents a two-dimensional micro-/nanoradian angle generator (2D-MNAG) that achieves high angular displacement resolution and repeatability using a piezo-driven flexure hinge for two-dimensional deflections and three capacitive sensors for output angle monitoring and feedback control. The principal error of the capacitive sensor for precision microangle measurement is analyzed and compensated for; so as to achieve a high angle output resolution of 10 nrad (0.002 arcsec) and positioning repeatability of 120 nrad (0...
November 19, 2017: Sensors
Tomoyuki Suzuki, Shunsuke Kawamoto, Atsuhiro Nakagawa, Toshiki Endo, Teiji Tominaga, Masatoshi Akiyama, Osamu Adachi, Kiichiro Kumagai, Yoshikatsu Saiki
Actuator-driven pulsed water-jet (ADPJ) dissection is an emerging surgical method for dissecting tissue without heat and mechanical injury to vessels. We elucidated the mechanical properties of the piezo ADPJ and evaluated its usefulness and safety in coronary artery bypass grafting procedures. The relationship between the input voltage (10-100 V) and peak pressure of the pulsed water jet was evaluated. The tissue strengths of swine internal thoracic and coronary arteries and the surrounding tissues were measured to assure tissue-selective dissection...
November 16, 2017: Journal of Artificial Organs: the Official Journal of the Japanese Society for Artificial Organs
Wei-Qiang Liao, Yuan-Yuan Tang, Peng-Fei Li, Yu-Meng You, Ren-Gen Xiong
Piezoelectric materials have been widely used in various applications, such as high-voltage sources, actuators, sensors, motors, fre-quency standard, vibration reducer, and so on. In the past decades, lead zirconate titanate (PZT) binary ferroelectric ceramics have dominated the commercial piezoelectric market due to their excellent properties near the morphotropic phase boundary (MPB), although they contain more than 60% toxic lead element. Here, we report a lead-free and one-composition molecular ferroelectric trimethylbromomethylammonium tribromomanganese (ΙΙ) (TMBM-MnBr3) with a large piezoelectric coefficient d33 of 112 pC/N along polar axis, comparable with those of typically one-composition piezoceramics such as BaTiO3 along polar axis [001] (~90 pC/N) and much greater than those of most known molecular ferroelectrics (almost below 40 pC/N)...
November 16, 2017: Journal of the American Chemical Society
Duan Zhang, Tanhua Jia, Ran Dong, Dengyun Chen
Two-dimensional A(III)B(VI) layered semiconductors have recently attracted great attention due to their potential applications in piezo-phototronics and optoelectronics. Here, we report the temperature-dependent photoluminescence (PL) of strained and unstrained GaSe flakes. It is found that, as the temperature increases, the PL from both the strained (wrinkled) and unstrained (flat) positions show a prominent red-shift to low energies. However, for the flat case, the slope of PL energy versus temperature at the range of 163-283 K is about -0...
November 8, 2017: Materials
Gianfranco Ulian, Giovanni Valdrè
The calcium apatite minerals are among the most studied in the biomaterial field because of their similarity with the mineral phase of bone tissues, which is mainly the hexagonal polymorph of hydroxylapatite. Given the growing interest both in the microscopic processes governing the behaviour of these natural biomaterials and in recent experimental methods to investigate the Raman response of hydroxylapatite upon mechanical loading, we report in the present work a detailed quantum mechanical analysis by DFT/B3LYP-D* approach on the Raman and infrared responses of hydroxylapatite upon deformation of its unit cell...
October 25, 2017: Journal of the Mechanical Behavior of Biomedical Materials
L Rigutti, L Venturi, J Houard, A Normand, E P Silaeva, M Borz, S A Malykhin, A N Obraztsov, A Vella
The application of a high electrostatic field at the apex of monocrystalline diamond nanoscale needles induces an energy splitting of the photoluminescence lines of color centers. In particular, the splitting of the zero-phonon line of the neutral nitrogen-vacancy complex (NV(0)) has been studied within a laser-assisted tomographic atom probe equipped with an in situ microphotoluminescence bench. The measured quadratic dependence of the energy splitting on the applied voltage corresponds to the stress generated on the metal-like apex surface by the electrostatic field...
November 8, 2017: Nano Letters
Emad A Ibrahim, Shamsa Al Awar, Zuhur H Balayah, Leontios J Hadjileontiadis, Ahsan H Khandoker
The aim of this study is to investigate that fetal heart rates (fHR) extracted from fetal phonocardiography (fPCG) could convey similar information of fHR from cardiotocography (CTG). Four-channel fPCG sensors made of low cost (<$1) ceramic piezo vibration sensor within 3D-printed casings were used to collect abdominal phonogram signals from 20 pregnant mothers (>34 weeks of gestation). A novel multi-lag covariance matrix-based eigenvalue decomposition technique was used to separate maternal breathing, fetal heart sounds (fHS) and maternal heart sounds (mHS) from abdominal phonogram signals...
2017: Frontiers in Physiology
Johanna Boutillier, Sébastien De Mezzo, Caroline Deck, Pascal Magnan, Pierre Naz, Rémy Willinger
To better protect soldiers from blast threat, that principally affect air-filled organs such a lung, it is necessary to develop an adapted injury criterion and, prior to this, to evaluate the response of a biological model against that threat. The objective of this study is to provide some robust data to quantify the chest response of post-mortem swine under blast loadings. 7 post-mortem swine (54.5 ± 2.6 kg), placed side-on to the threat and against the ground, were exposed to 5 shock-waves of increasing intensities...
October 25, 2017: Journal of Biomechanics
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