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Y J Lee, S R Ham, J H Kim, T H Yoo, S R Kim, Y T Lee, D K Hwang, B Angadi, W S Seo, B K Ju, W K Choi
We propose the unique structure of highly dispersible single-walled carbon nanotubes (SWCNTs) in various solvents and polymers using the ZnO nano particle template. Buckled nanospring-shaped carbon nanotubes (NS-CNTs) were synthesized by a chemical reaction of ZnO nanoparticles with acid-treated SWCNTs and then dissolving ZnO through chemical etching. The unique structure of distorted hexagonal NS-CNTs encircled around ZnO nanoparticles was formed by the bending of SWCNTs caused by the agglomeration of chemically adsorbed Zn(OH)2 , which is further crystallized as the polycrystalline ZnO inner core...
March 19, 2018: Scientific Reports
Samuel D Clark, Rachel Mikofsky, Jacqueline Lawson, David Sulzer
Multiphoton microscopy has been widely adapted for imaging neurons in vivo. Repeated imaging requires implantation of a cranial window or repeated thinning of the skull. Cranial window surgery is typically performed with a high speed rotary drill, and many investigators find it challenging to prevent the drill from damaging the delicate dura and blood vessels. Extensive training and practice is required to remove the bone without damage to underlying tissue and thus cranial window surgery can be difficult, time consuming, and produce tissue damage...
March 2, 2018: Journal of Visualized Experiments: JoVE
Akihiro Koba, Ryuichiro Tanoue, Shogo Kikuta, Shingo Hirashima, Yoshihiro Miyazono, Jingo Kusukawa
Mandibular osteotomy carries with it a risk of damaging blood vessels and nerves when using traditional surgical techniques. Piezosurgery® , is a new technique that uses ultrasonic vibration to enable bone-selective sectioning without damage to the surrounding soft tissues. However, paralysis may not be completely eliminated using Piezosurgery® for osteotomy. We investigated how piezoelectric surgery in bilateral sagittal splitting ramus osteotomy (BSSRO) affected the surrounding soft tissue. Forty-four patients with skeletal mandibular prognathism underwent mandibular setback with BSSRO...
March 16, 2018: Kurume Medical Journal
Mirko Moroni, M Rocio Servin-Vences, Raluca Fleischer, Oscar Sánchez-Carranza, Gary R Lewin
Mechanosensitive PIEZO ion channels are evolutionarily conserved proteins whose presence is critical for normal physiology in multicellular organisms. Here we show that, in addition to mechanical stimuli, PIEZO channels are also powerfully modulated by voltage and can even switch to a purely voltage-gated mode. Mutations that cause human diseases, such as xerocytosis, profoundly shift voltage sensitivity of PIEZO1 channels toward the resting membrane potential and strongly promote voltage gating. Voltage modulation may be explained by the presence of an inactivation gate in the pore, the opening of which is promoted by outward permeation...
March 15, 2018: Nature Communications
Pavel Honzatko, Yauhen Baravets, Ashwin Kumar Myakalwar
We present a broadly tunable single-frequency ytterbium-doped fiber laser. Its broadband tunability is made possible by low resonator losses. The wavelength is determined by a grating filter, while the single-frequency regime is achieved by filtering the longitudinal modes in a fiber ring resonance filter. We obtained a tuning range from 1023 nm to 1107 nm. A feedback loop driving a fiber stretcher actuated by a piezo-element prevents mode hopping. Based on the coherent delayed self-heterodyne interferometry, the laser linewidth is estimated to be 600 Hz with feedback open and 11...
March 15, 2018: Optics Letters
David J Beech, Bailong Xiao
No abstract text is available yet for this article.
March 15, 2018: Journal of Physiology
Matthias C Wapler, Florian Lemke, Gazmed Alia, Ulrike Wallrabe
We present a varifocal mirror based on a piezo-actuated glass membrane that can be used as a secondary mirror in miniature Cassegrain-type mirror- or catadioptric objectives. The mirror section has a diameter of 10 mm on a clear membrane diameter of 23 mm, with a focal range of ±8 m-1 and a response time on the millisecond-scale. The two piezo layers enable an aspherical tuning range that covers the elliptic, parabolic and hyperbolic regime over most of the focal range. We demonstrate the application of the mirror in a simple catadioptric telefocus objective with a focal length of 68 mm at an aperture of 22 mm and a thickness of 16...
March 5, 2018: Optics Express
Brahmanandam Javvaji, Bo He, Xiaoying Zhuang
Graphene is a non-piezoelectric material. Engineering the piezoelectricity in graphene is possible
 with the help of impurities, defects and structural modifications. This study reports the mechanism
 of strain induced polarization and the estimation of piezoelectric and flexoelectric coefficients for
 graphene system. The combination of charge-dipole potential and the strong many-body potential
 is employed for describing the inter-atomic interactions. The breaking of symmetry in graphene
 material is utilized to generate the polarization...
March 9, 2018: Nanotechnology
Ming Zhong, Yulia Komarova, Jalees Rehman, Asrar B Malik
No abstract text is available yet for this article.
January 1, 2018: Pulmonary Circulation
Francesca Urban, Maurizio Passacantando, Filippo Giubileo, Laura Iemmo, Antonio Di Bartolomeo
We report the electrical characterization and field emission properties of MoS 2 bilayers deposited on a SiO 2 / Si substrate. Current-voltage characteristics are measured in the back-gate transistor configuration, with Ti contacts patterned by electron beam lithography. We confirm the n-type character of as-grown MoS 2 and we report normally-on field-effect transistors. Local characterization of field emission is performed inside a scanning electron microscope chamber with piezo-controlled tungsten tips working as the anode and the cathode...
March 8, 2018: Nanomaterials
Makito Iizuka, Masaaki Kobayashi, Yoshimasa Hasegawa, Kazuhide Tomita, Reiko Takeshima, Masahiko Izumizaki
We tried to develop a new device to detect laryngeal movement noninvasively. We made small piezo pressure sensors (length, 1.5 mm, width, 7.0 mm), and five of these were lined up with 3.0-mm intervals and embedded in the middle of a palm-sized urethane resin sheet. This sheet was lightly attached to the ventral surface of the neck near the laryngeal prominence. The first and second peaks obtained from each sensor should correspond to the period when the larynx moves to the upper and lower positions during swallowing...
March 5, 2018: Journal of Physiological Sciences: JPS
Kiho Kim, Jiwon Yun, Donghyuck Lee, Dohun Kim
A simple and convenient design enables real-time three-dimensional position tracking of nitrogen-vacancy (NV) centers in diamond. The system consists entirely of commercially available components (a single-photon counter, a high-speed digital-to-analog converter, a phase-sensitive detector-based feedback device, and a piezo stage), eliminating the need for custom programming or rigorous optimization processes. With a large input range of counters and trackers combined with high sensitivity of single-photon counting, high-speed position tracking (upper bound recovery time of 0...
February 2018: Review of Scientific Instruments
S Charles Doret
We present an inexpensive, low-noise (<260 μVrms , 0.1 Hz-100 kHz) design for a piezo driver suitable for frequency tuning of external-cavity diode lasers. This simple driver improves upon many commercially available drivers by incorporating circuitry to produce a "feed-forward" signal appropriate for making simultaneous adjustments to the piezo voltage and laser current, enabling dramatic improvements in a mode-hop-free laser frequency tuning range. We present the theory behind our driver's operation, characterize its output noise, and demonstrate its use in absorption spectroscopy on the rubidium D1 line...
February 2018: Review of Scientific Instruments
Krzysztof Tyszka, Marek Dobosz, Tomasz Bilaszewski
Aiming to increase laser beam pointing stability required in interferometric measurements, we designed a laser beam deflector intended for active laser beam stabilization systems. The design is based on two wedge-prisms: the deflecting wedge driven by a tilting piezo-platform and the fixed wedge to compensate initial beam deflection. Our design allows linear beam steering, independently in the horizontal or vertical direction, with resolution of less than 1 μrad in a range of more than 100 μrad, and no initial deflection of the beam...
February 2018: Review of Scientific Instruments
F Arnold, M Naumann, Th Lühmann, A P Mackenzie, E Hassinger
Torque magnetometry is a key method to measure the magnetic anisotropy and quantum oscillations in metals. In order to resolve quantum oscillations in sub-millimeter sized samples, piezo-electric micro-cantilevers were introduced. In the case of strongly correlated metals with large Fermi surfaces and high cyclotron masses, magnetic torque resolving powers in excess of 104 are required at temperatures well below 1 K and magnetic fields beyond 10 T. Here, we present a new broadband read-out scheme for piezo-electric micro-cantilevers via Wheatstone-type resistance measurements in magnetic fields up to 15 T and temperatures down to 200 mK...
February 2018: Review of Scientific Instruments
Sudipta Goswami, Dipten Bhattacharya, Chandan K Ghosh, Barnali Ghosh, S D Kaushik, V Siruguri, P S R Krishna
Using high resolution powder x-ray and neutron diffraction experiments, we determined the off-centered displacement of the ions within a unit cell and magnetoelectric coupling in nanoscale BiFeO3 (≈20-200 nm). We found that both the off-centered displacement of the ions and magnetoelectric coupling exhibit nonmonotonic variation with particle size. They increase as the particle size reduces from bulk and reach maximum around 30 nm. With further decrease in particle size, they decrease precipitously. The magnetoelectric coupling is determined by the anomaly in off-centering of ions around the magnetic transition temperature (TN )...
February 27, 2018: Scientific Reports
Roberto Lo Conte, Zhuyun Xiao, Cai Chen, Camelia Veronica Stan, Jon Gorchon, Amal El-Ghazaly, Mark E Nowakowski, Hyunmin Sohn, Akshay Pattabi, Andreas Scholl, Nobumichi Tamura, Abdon Sepulveda, Gregory P Carman, Robert N Candler, Jeffrey Bokor
Composite multiferroic systems, consisting of a piezoelectric substrate coupled with a ferromagnetic thin film, are of great interest from a technological point of view since they offer a path towards the development of ultra-low power magnetoelectric devices. The key aspect of those systems is the possibility to control magnetization via an electric field, relying on the magneto-elastic coupling at the interface between the piezoelectric and the ferromagnetic components. Accordingly, a direct measurement of both the electrically induced magnetic behavior and of the piezo-strain driving such behavior is crucial for better understanding and further developing these materials systems...
February 26, 2018: Nano Letters
Qiancheng Zhao, Heng Zhou, Shaopeng Chi, Yanfeng Wang, Jianhua Wang, Jie Geng, Kun Wu, Wenhao Liu, Tingxin Zhang, Meng-Qiu Dong, Jiawei Wang, Xueming Li, Bailong Xiao
The mechanosensitive Piezo channels function as key eukaryotic mechanotransducers. However, their structures and mechanogating mechanisms remain unknown. Here we determine the three-bladed, propeller-like electron cryo-microscopy structure of mouse Piezo1 and functionally reveal its mechanotransduction components. Despite the lack of sequence repetition, we identify nine repetitive units consisting of four transmembrane helices each-which we term transmembrane helical units (THUs)-which assemble into a highly curved blade-like structure...
February 22, 2018: Nature
Calum Crake, Spencer T Brinker, Christian M Coviello, Margaret Livingstone, Nathan J McDannold
Previous work has demonstrated that passive acoustic imaging may be used alongside MRI for monitoring of focused ultrasound therapy. However, past implementations have generally made use of either linear arrays originally designed for diagnostic imaging or custom narrowband arrays specific to in-house therapeutic transducer designs, neither of which is fully compatible with clinical MR-guided focused ultrasound devices. Here we have designed an array which is suitable for use within an FDA-approved MR-guided transcranial focused ultrasound device, within the bore of a 3 Tesla clinical MRI scanner...
February 20, 2018: Physics in Medicine and Biology
Xing Wang, Guang-Ming Zhang, Hongwei Ma, Yishu Zhang, Doudou Wang
In ultrasonic array imaging, 3D ultrasonic wavefields are normally recorded by an ultrasonic piezo array transducer. Its performance is limited by the configuration and size of the array transducer. In this paper, a method based on digital holographic interferometry is proposed to record the 3D ultrasonic wavefields instead of the array transducer, and the measurement system consisting of a pulsed laser, ultrasonic excitation, and synchronization and control circuit is designed. A consecutive sequence of holograms of ultrasonic wavefields are recorded by the system...
February 13, 2018: Sensors
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