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voltage sensor

Joseph Santos-Sacchi, Winston Tan
The voltage-dependent protein SLC26a5 (prestin) underlies outer hair cell electromotility (eM), which is responsible for cochlear amplification in mammals. The electrical signature of eM is a bell-shaped nonlinear capacitance (NLC), deriving from prestin sensor-charge (Qp ) movements, which peaks at the membrane voltage, Vh , where charge is distributed equally on either side of the membrane. Voltage dependencies of NLC and eM differ depending on interrogation frequency and intracellular chloride, revealing slow intermediate conformational transitions between anion binding and voltage-driven Qp movements...
June 13, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Xinyuan Zhou, Jinxiao Wang, Zhou Wang, Yuzhi Bian, Ying Wang, Ning Han, Yunfa Chen
Low concentration acetone gas detection is significantly important for diabetes diagnosis as 1.8⁻10 ppm of acetone exists in exhaled breath from diabetes patients. A new interlocking p+n field-effect transistor (FET) circuit has been proposed for Mn-doped ZnO nanoparticles (MZO) to detect the acetone gas at low concentration, especially close to 1.8 ppm. It is noteworthy that MZO in this interlocking amplification circuit shows a low voltage signal of <0.3 V to the acetone <2 ppm while it displays a transilient response with voltage signal >4...
June 12, 2018: Sensors
Thye Foo Choo, Nur Ubaidah Saidin, Kuan Ying Kok
The capability of zinc oxide (ZnO) as a hydrogen sensing element has been pushed to its limits. Different methods have been explored to extend its sensing capability. In this paper, we report a novel approach which significantly improves the hydrogen sensing capability of zinc oxide by applying a bias voltage to ZnO nanorods as the sensing elements. Zinc oxide in the form of aligned nanorods was first synthesized on an Au-coated Si(111) substrate using a facile method via the galvanic-assisted chemical process...
May 2018: Royal Society Open Science
Chang-Mou Wu, Min-Hui Chou, Wun-Yuan Zeng
Polyvinylidene fluoride (PVDF) shows piezoelectricity related to its &beta;-phase content and mechanical and electrical properties influenced by its morphology and crystallinity. Electrospinning (ES) can produce ultrafine and well-aligned PVDF nanofibers. In this study, the effects of the presence of carbon nanotubes (CNT) and optimized ES parameters on the crystal structures and piezoelectric properties of aligned PVDF/CNT nanofibrous membranes were examined. The optimal &beta; content and piezoelectric coefficient (d33 ) of the aligned electrospun PVDF reached 88% and 27...
June 10, 2018: Nanomaterials
Zhenran Gao, Yan Zhu, Cheng Liu, Hongzhou Qian, Weixing Cao, Jun Ni
To meet the demand of intelligent irrigation for accurate moisture sensing in the soil vertical profile, a soil profile moisture sensor was designed based on the principle of high-frequency capacitance. The sensor consists of five groups of sensing probes, a data processor, and some accessory components. Low-resistivity copper rings were used as components of the sensing probes. Composable simulation of the sensor&rsquo;s sensing probes was carried out using a high-frequency structure simulator. According to the effective radiation range of electric field intensity, width and spacing of copper ring were set to 30 mm and 40 mm, respectively...
May 21, 2018: Sensors
Ben Guan, Yong Zang, Xiaohui Han, Kailun Zheng
Driven by the demands for contactless stress detection, technologies are being used for shape control when producing cold-rolled strips. This paper presents a novel contactless stress detection technology based on a magnetoresistance sensor and the magnetoelastic effect, enabling the detection of internal stress in manufactured cold-rolled strips. An experimental device was designed and produced. Characteristics of this detection technology were investigated through experiments assisted by theoretical analysis...
May 21, 2018: Sensors
Federica Mariani, Isacco Gualandi, Marta Tessarolo, Beatrice Fraboni, Erika Scavetta
Organic electrochemical transistors (OECTs) are bioelectronic devices able to bridge electronic and biological domains with especially high amplification and configurational versatility, thus standing out as promising platforms for healthcare applications and portable sensing technologies. Here, we have optimised the synthesis of two pH-sensitive composites of PEDOT (poly(3,4-ethylenedioxythiophene) doped with pH dyes (BTB and MO , i.e. Bromothymol Blue and Methyl Orange, respectively), showing their ability to successfully convert the pH into an electrical signal...
June 8, 2018: ACS Applied Materials & Interfaces
Angelica Lopez-Rodriguez, Miguel Holmgren
Most membrane proteins are subject to posttranslational glycosylation, which influences protein function, folding, solubility, stability, and trafficking. This modification has been proposed to protect proteins from proteolysis and modify protein-protein interactions. Voltage-activated ion channels are heavily glycosylated, which can result in up to 30% of the mature molecular mass being contributed by glycans. Normally, the functional consequences of glycosylation are assessed by comparing the function of fully glycosylated proteins with those in which glycosylation sites have been mutated or by expressing proteins in model cells lacking glycosylation enzymes...
June 7, 2018: Journal of General Physiology
Helmut Plattner, Alexei Verkhratsky
The aim of the present article is to analyse the evolutionary links between protozoa and neuronal and neurosecretory cells. To this effect we employ functional and topological data available for ciliates, in particular for Paramecium. Of note, much less data are available for choanoflagellates, the progenitors of metazoans, which currently are in the focus of metazoan genomic data mining. Key molecular players are found from the base to the highest levels of eukaryote evolution, including neurones and neurosecretory cells...
July 2018: Cell Calcium
Guoqing Fu, Sameer R Sonkusale
Luminescence plays an important role in many scientific and industrial applications. This paper proposes a novel complementary metal-oxide-semiconductor (CMOS) sensor chip that can realize both luminescence intensity and lifetime sensing. To enable high sensitivity, we propose parasitic insensitive multicycle charge modulation scheme for low-light lifetime extraction benefiting from simplicity, accuracy, and compatibility with deeply scaled CMOS process. The designed in-pixel capacitive transimpedance amplifier (CTIA) based structure is able to capture the weak luminescence-induced voltage signal by accumulating photon-generated charges in 25 discrete gated 10-ms time windows and 10-μs pulsewidth...
June 2018: IEEE Transactions on Biomedical Circuits and Systems
Xiayi Liu, Jiafeng Yao, Tong Zhao, Hiromichi Obara, Yahui Cui, Masahiro Takei
Contact impedance has an important effect on micro electrical impedance tomography (EIT) sensors compared to conventional macro sensors. In the present work, a complex contact impedance effect ratio ξ is defined to quantitatively evaluate the effect of the contact impedance on the accuracy of the reconstructed images by micro EIT. Quality of the reconstructed image under various ξ is estimated by the phantom simulation to find the optimum algorithm. The generalized vector sampled pattern matching (GVSPM) method reveals the best image quality and the best tolerance to ξ...
June 2018: IEEE Transactions on Biomedical Circuits and Systems
Mehdi Noormohammadi Khiarak, Ekaterina Martianova, Cyril Bories, Sylvain Martel, Christophe D Proulx, Yves De Koninck, Benoit Gosselin
Fluorescence biophotometry measurements require wide dynamic range (DR) and high-sensitivity laboratory apparatus. Indeed, it is often very challenging to accurately resolve the small fluorescence variations in presence of noise and high-background tissue autofluorescence. There is a great need for smaller detectors combining high linearity, high sensitivity, and high-energy efficiency. This paper presents a new biophotometry sensor merging two individual building blocks, namely a low-noise sensing front-end and a order continuous-time modulator (CTSDM), into a single module for enabling high-sensitivity and high energy-efficiency photo-sensing...
June 2018: IEEE Transactions on Biomedical Circuits and Systems
Veerappan Nagarajan, Arunachalam Thayumanavan
Spinel CdFe2 O4 thin films were synthesized by spray pyrolysis. The structural probe studies confirmed the multicrystalline nature of the films with their spinel structure. The crystallites have sizes between 13 and 37 nm and island morphology. The energy dispersive spectroscopy reveals the presence of iron, oxygen and cadmium in the film. The room temperature electrical resistance of the thin film, best measured at a voltage of 10 V, decreases rapidly if it is exposed to vapors of formaldehyde or ethanol...
June 6, 2018: Mikrochimica Acta
Wuli Pu, Daihua Fu, Zhanhua Wang, Xinpeng Gan, Xili Lu, Li Yang, Hesheng Xia
Combining self-healing functions with damage diagnosing, which can achieve timely healing autonomously, is expected to improve the reliability and reduce life cycle cost of materials. Here, a flexible conductive composite composed of a dynamically crosslinked polyurethane bearing Diels-Alder bonds (PUDA) and carbon nanotubes (CNTs), which possess both crack diagnosing and self-healing functions, is reported. The introduced dynamic Diels-Alder bonds endow the materials self-healing function and the powder-based preparation route based on the specially designed CNTs-coated PUDA micropowders leads to the formation of segregated CNTs network, which makes the composite possess excellent mechanical properties and high conductivity...
May 2018: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Smiruthi Ramasubramanian, Yoram Rudy
Relating ion channel (iCh) structural dynamics to physiological function remains a challenge. Current experimental and computational techniques have limited ability to explore this relationship in atomistic detail over physiological timescales. A framework associating iCh structure to function is necessary for elucidating normal and disease mechanisms. We formulated a modeling schema that overcomes the limitations of current methods through applications of artificial intelligence machine learning. Using this approach, we studied molecular processes that underlie human IKs voltage-mediated gating...
June 5, 2018: Biophysical Journal
Christine A Snidal, Qi Li, Brittany B Elliott, Henry K-H Mah, Robert H C Chen, Sabiha R Gardezi, Elise F Stanley
Neurotransmitter is released from presynaptic nerve terminals at fast-transmitting synapses by the action potential-gating of voltage dependent calcium channels (CaV), primarily of the CaV2.1 and CaV2.2 types. Entering Ca2+ diffuses to a nearby calcium sensor associated with a docked synaptic vesicle (SV) and initiates its fusion and discharge. Our previous findings that single CaVs can gate SV fusion argued for one or more tethers linking CaVs to docked SVs but the molecular nature of these tethers have not been established...
2018: Frontiers in Cellular Neuroscience
Jiangwei Liu, Yasuo Koide
Thanks to its excellent intrinsic properties, diamond is promising for applications of high-power electronic devices, ultraviolet detectors, biosensors, high-temperature tolerant gas sensors, etc. Here, an overview of high- k oxides on hydrogenated-diamond (H-diamond) for metal-oxide-semiconductor (MOS) capacitors and MOS field-effect transistors (MOSFETs) is demonstrated. Fabrication routines for the H-diamond MOS capacitors and MOSFETs, band configurations of oxide/H-diamond heterointerfaces, and electrical properties of the MOS and MOSFETs are summarized and discussed...
June 4, 2018: Sensors
Daniel T Infield, Elizabeth E L Lee, Jason D Galpin, Grace D Galles, Francisco Bezanilla, Christopher A Ahern
Voltage-dependent activation of voltage-gated cation channels results from the outward movement of arginine-bearing helices within proteinaceous voltage sensors. The voltage-sensing residues in potassium channels have been extensively characterized, but current functional approaches do not allow a distinction between the electrostatic and steric contributions of the arginine side chain. Here we use chemical misacylation and in vivo nonsense suppression to encode citrulline, a neutral and nearly isosteric analogue of arginine, into the voltage sensor of the Shaker potassium channel...
June 4, 2018: Journal of General Physiology
Sumeet Shrestha, Shoji Kawahito, Hiroki Kamehama, Syunta Nakanishi, Keita Yasutomi, Keiichiro Kagawa, Nobukazu Teranishi, Ayaki Takeda, Takeshi Go Tsuru, Ikuo Kurachi, Yasuo Arai
In this paper, we report on the development of a monolithic active pixel sensor for X-ray imaging using 0.2 µm fully depleted silicon-on-insulator (SOI)-based technology to support next generation astronomical satellite missions. Detail regarding low-noise dual-gain SOI based pixels with a charge sensitive amplifier and pinned depleted diode sensor structure is presented. The proposed multi-well sensor structure underneath the fully-depleted SOI allows the design of a detector with low node capacitance and high charge collection efficiency...
June 1, 2018: Sensors
SungJin Kim, Dong-Gyu Kim, Chanho Kim, Dong Soo Lee, Behnam Samadpoor Rikan, YoungGun Pu, Sang-Sun Yoo, Minjae Lee, KeumCheol Hwang, Youngoo Yang, Kang-Yoon Lee
This paper presents a 612⁻1152 MHz Injection-Locked Frequency Multiplier (ILFM). The proposed ILFM is used to send an input signal to a receiver in only the I/Q mismatch calibration mode. Adopting a Phase-Locked Loop (PLL) to calibrate the receiver places a burden on this system because of the additional area and power consumption that is required. Instead of the PLL, to satisfy high-frequency, low-jitter and low-area requirements, a Ring Oscillator is adopted in the system. The free-running frequency of the ILFM is automatically and digitally calibrated to reflect the frequency of the injected signal from the harmonics of the reference clock...
June 1, 2018: Sensors
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