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Jing Li, Zhiren Zhu, Lichen Fang, Shu Guo, Ugur Erturun, Zeyu Zhu, James E West, Somnath Ghosh, Sung Hoon Kang
Piezoelectric composite (p-NC) made of a polymeric matrix and piezoelectric nanoparticles with conductive additives is an attractive material for many applications. As the matrix of p-NC is made of viscoelastic materials, both elastic and viscous characteristics of the matrix are expected to contribute to the piezoelectric response of p-NC. However, there is limited understanding of how viscoelasticity influences the piezoelectric performance of p-NC. Here we combined analytical and numerical analyses with experimental studies to investigate effects of viscoelasticity on piezoelectric performance of p-NC...
September 15, 2017: Nanoscale
Astrid Gesper, Philipp Hagemann, Patrick Happel
Nanoparticles have the potential to become versatile tools in the medical and life sciences. One potential application is delivering drugs or other compounds to the cell cytoplasm, which requires the nanoparticles to bind to or cross the cell membrane. However, there are only a few tools available which allow studying the interaction of nanoparticles and the cell membrane of living cells in a physiological environment. Currently, the tool which least biases living cells is Scanning Ion Conductance Microscopy (SICM)...
September 14, 2017: Nanoscale
Wenjun Zheng, Frederick Sachs
The PIEZO channels, a family of mechanosensitive channels in vertebrates, feature a fast activation by mechanical stimuli (e.g., membrane tension) followed by a slower inactivation. Although a medium-resolution structure of the trimeric form of PIEZO1 was solved by cryo-electron microscopy (cryo-EM), key structural changes responsible for the channel activation and inactivation are still unknown. Toward decrypting the structural mechanism of the PIEZO1 activation and inactivation, we performed systematic coarse-grained modeling using an elastic network model and related modeling/analysis tools (i...
September 14, 2017: Proteins
Chunyan Jiang, Liang Jing, Xin Huang, Mengmeng Liu, Chunhua Du, Ting Liu, Xiong Pu, Weiguo Hu, Zhong Lin Wang
The piezo-phototronic effect is about the tuning of piezoelectric polarization charges at the interface for largely enhancing the efficiency of optoelectronic processes related to carrier separation or recombination. Here, we demonstrated the enhanced short-circuit current density and the conversion efficiency of the InGaN/GaN multiple quantum wells (MQWs) solar cells with an external stress applied onto the device. The external stress-induced piezoelectric charges generated at the interfaces of InGaN and GaN compensate the piezoelectric charges induced by lattice mismatch stress in the InGaN wells...
September 5, 2017: ACS Nano
Zhao Feng, Jie Ling, Min Ming, Xiao-Hui Xiao
For precision motion, high-bandwidth and flexible tracking are the two important issues for significant performance improvement. Iterative learning control (ILC) is an effective feedforward control method only for systems that operate strictly repetitively. Although projection ILC can track varying references, the performance is still limited by the fixed-bandwidth Q-filter, especially for triangular waves tracking commonly used in a piezo nanopositioner. In this paper, a wavelet transform-based linear time-varying (LTV) Q-filter design for projection ILC is proposed to compensate high-frequency errors and improve the ability to tracking varying references simultaneously...
August 2017: Review of Scientific Instruments
M W Airey, R G Harrison, K A Nicoll, P D Williams, G J Marlton
A lightweight and low power oscillating microbalance for in situ sampling of atmospheric ice and volcanic ash is described for airborne platforms. Using a freely exposed collecting wire fixed at only one end to a piezo transducer, the instrument collects airborne materials. Accumulated mass is determined from the change in natural frequency of the wire. The piezo transducer is used in a dual mode to both drive and detect the oscillation. Three independent frequency measurement techniques are implemented with an on-board microcontroller: a frequency sweep, a Fourier spectral method, and a phase-locked loop...
August 2017: Review of Scientific Instruments
Zuocheng Zhang, Likai Li, Jason Horng, Nai Zhou Wang, Fangyuan Yang, Yijun Yu, Yu Zhang, Guorui Chen, Kenji Watanabe, Takashi Taniguchi, Xian Hui Chen, Feng Wang, Yuanbo Zhang
Energy bandgap largely determines the optical and electronic properties of a semiconductor. Variable bandgap therefore makes versatile functionality possible in a single material. In layered material black phosphorus, the bandgap can be modulated by the number of layers; as a result, few-layer black phosphorus has discrete bandgap values that are relevant for optoelectronic applications in the spectral range from red, in monolayer, to mid-infrared in the bulk limit. Here, we further demonstrate continuous bandgap modulation by mechanical strain applied through flexible substrates...
September 11, 2017: Nano Letters
Yoshitaka Ehara, Shintaro Yasui, Takahiro Oikawa, Takahisa Shiraishi, Takao Shimizu, Hiroki Tanaka, Noriyuki Kanenko, Ronald Maran, Tomoaki Yamada, Yasuhiko Imai, Osami Sakata, Nagarajan Valanoor, Hiroshi Funakubo
Ferroelastic domain switching significantly affects piezoelectric properties in ferroelectric materials. The ferroelastic domain switching and the lattice deformation of both a-domains and c-domains under an applied electric field were investigated using in-situ synchrotron X-ray diffraction in conjunction with a high-speed pulse generator set up for epitaxial (100)/(001)-oriented tetragonal Pb(Zr0.4Ti0.6)O3 (PZT) films grown on (100) c SrRuO3//(100)KTaO3 substrates. The 004 peak (c-domain) position shifts to a lower 2θ angle, which demonstrates the elongation of the c-axis lattice parameter of the c-domain under an applied electric field...
August 29, 2017: Scientific Reports
Luis Eduardo Charles Pagotto, Thiago de Santana Santos, Sara Juliana de Abreu de Vasconcellos, Joanes Silva Santos, Paulo Ricardo Saquete Martins-Filho
PURPOSE: The purpose of this study was to perform a systematic review and meta-analysis of complications after orthognathic surgery comparing piezo-surgery with conventional osteotomy. METHODS: We conducted this study according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We performed a systematic search of PubMed, Scopus, Science Direct, Lilacs, Cochrane Central Register of Controlled Trials, Google Scholar, and OpenThesis to identify randomized and nonrandomized controlled trials (RCTs and nRCTs, respectively) comparing patient outcomes (operative time, intraoperative blood loss, postoperative swelling, pain, neurosensitivity) after orthognathic surgery by piezoelectric or conventional osteotomy...
July 1, 2017: Journal of Cranio-maxillo-facial Surgery
Yu Zhou, Di Wu, Yihan Zhu, Yujin Cho, Qing He, Xiao Yang, Kevin Herrera, Zhaodong Chu, Yu Han, Michael C Downer, Hailin Peng, Keji Lai
Piezoelectric and ferroelectric properties in the two-dimensional (2D) limit are highly desired for nanoelectronic, electromechanical, and optoelectronic applications. Here we report the first experimental evidence of out-of-plane piezoelectricity and ferroelectricity in van der Waals layered α-In2Se3 nanoflakes. The noncentrosymmetric R3m symmetry of the α-In2Se3 samples is confirmed by scanning transmission electron microscopy, second-harmonic generation, and Raman spectroscopy measurements. Domains with opposite polarizations are visualized by piezo-response force microscopy...
September 13, 2017: Nano Letters
Ben De Pauw, Sidney Goossens, Thomas Geernaert, Dimitrios Habas, Hugo Thienpont, Francis Berghmans
Conventional contact sensors used for Lamb wave-based ultrasonic inspection, such as piezo-electric transducers, measure omnidirectional strain and do not allow distinguishing between fundamental symmetric and anti-symmetric modes. In this paper, we show that the use of a single fibre Bragg grating created in a dedicated microstructured optical fibre allows one to directly make the distinction between these fundamental Lamb wave modes. This feature stems from the different sensitivities of the microstructured fibre to axial and transverse strain...
August 24, 2017: Sensors
Rena Akahori, Itaru Yanagi, Yusuke Goto, Kunio Harada, Takahide Yokoi, Ken-Ichi Takeda
To achieve DNA sequencing with solid-state nanopores, the speed of the DNA in the nanopore must be controlled to obtain sequence-specific signals. In this study, we fabricated a nanopore-sensing system equipped with a DNA motion controller. DNA strands were immobilized on a Si probe, and approach of this probe to the nanopore vicinity could be controlled using a piezo actuator and stepper motor. The area of the Si probe was larger than the area of the membrane, which meant that the immobilized DNA could enter the nanopore without the need for the probe to scan to determine the location of the nanopore in the membrane...
August 22, 2017: Scientific Reports
Yao Sun, Zhigang Hu, Dan Zhao, Kaiyang Zeng
Experimental investigation of functional properties of metal-organic frameworks (MOFs) at nanoscale precision is challenging and rarely reported. In this study, we report the piezo- and ferroelectric properties of NUS-6 MOF nanocrystals using dual AC resonance tracking piezoresponse force microscopy and piezoresponse force spectroscopy for the first time. Both NUS-6-(Hf) and NUS-6-(Zr) nanocrystals displayed anomalous piezoelectricity with the calculated piezoelectric coefficient dzz constants of 2.0-3.5 pm V(-1) and 1...
August 24, 2017: Nanoscale
Ali Al-Naji, Asanka G Perera, Javaan Chahl
BACKGROUND: Remote physiological measurement might be very useful for biomedical diagnostics and monitoring. This study presents an efficient method for remotely measuring heart rate and respiratory rate from video captured by a hovering unmanned aerial vehicle (UVA). The proposed method estimates heart rate and respiratory rate based on the acquired signals obtained from video-photoplethysmography that are synchronous with cardiorespiratory activity. METHODS: Since the PPG signal is highly affected by the noise variations (illumination variations, subject's motions and camera movement), we have used advanced signal processing techniques, including complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and canonical correlation analysis (CCA) to remove noise under these assumptions...
August 8, 2017: Biomedical Engineering Online
Wuxiao Han, Haoxuan He, Linlin Zhang, Chuanyi Dong, Hui Zeng, Yitong Dai, Lili Xing, Yan Zhang, Xinyu Xue
The emerging multifunctional flexible electronic-skin for establishing body-electric interaction can enable real-time monitoring of personal health status as a new personalized medicine technique. A key difficulty in the device design is the flexible power supply. Here a self-powered wearable noninvasive electronic-skin for perspiration analysis has been realized on the basis of a piezo-biosensing unit matrix of enzyme/ZnO nanoarrays. The electronic-skin can detect lactate, glucose, uric acid, and urea in the perspiration, and no outside electrical power supply or battery is used in the biosensing process...
August 23, 2017: ACS Applied Materials & Interfaces
Atsuo Ogura
Viable and fertile mice can be generated by somatic nuclear transfer into enucleated oocytes, presumably because the transplanted somatic cell genome becomes reprogrammed by factors in the oocyte. The first somatic cloned offspring of mice were obtained by directly injecting donor nuclei into recipient enucleated oocytes. When this method is used (the so-called Honolulu method of somatic cell nuclear transfer [SCNT]), the donor nuclei readily and completely condense within the enucleated metaphase II-arrested oocytes, which contain high levels of M-phase-promoting factor (MPF)...
August 1, 2017: Cold Spring Harbor Protocols
Meng Zhang, Zhigang Liu, Yu Zhu, Mingfan Bu, Jun Hong
In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems...
July 2017: Review of Scientific Instruments
S L Alper
Mutations in the genes encoding the mechanosensitive cation channels PIEZO1 and PIEZO2 are responsible for multiple hereditary human diseases. Loss-of-function mutations in the human PIEZO1 gene cause autosomal recessive congenital lymphatic dysplasia. Gain-of-function mutations in the human PIEZO1 gene cause the autosomal dominant hemolytic anemia, hereditary xerocytosis (also known as dehydrated stomatocytosis). Loss-of-function mutations in the human PIEZO2 gene cause an autosomal recessive syndrome of muscular atrophy with perinatal respiratory distress, arthrogryposis, and scoliosis...
2017: Current Topics in Membranes
C D Cox, N Bavi, B Martinac
Piezo channels are a ubiquitously expressed, principal type of molecular force sensor in eukaryotes. They enable cells to decode a myriad of physical stimuli and are essential components of numerous mechanosensory processes. Central to their physiological role is the ability to change conformation in response to mechanical force. Here we discuss the evolutionary origin of Piezo in relation to other MS channels in addition to the force that gates Piezo channels. In particular, we discuss whether Piezo channels are inherently mechanosensitive in accordance with the force-from-lipid paradigm which has been firmly established for bacterial MS channels and two-pore domain K(+) (K2P) channels...
2017: Current Topics in Membranes
M M Maneshi, P A Gottlieb, S Z Hua
Microfluidics is an interdisciplinary field intersecting many areas in engineering. Utilizing a combination of physics, chemistry, biology, and biotechnology, along with practical applications for designing devices that use low volumes of fluids to achieve high-throughput screening, is a major goal in microfluidics. Microfluidic approaches allow the study of cells growth and differentiation using a variety of conditions including control of fluid flow that generates shear stress. Recently, Piezo1 channels were shown to respond to fluid shear stress and are crucial for vascular development...
2017: Current Topics in Membranes
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