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Mohammad T Mazhab-Jafari, Alexis Rohou, Carla Schmidt, Stephanie A Bueler, Samir Benlekbir, Carol V Robinson, John L Rubinstein
Vacuolar-type ATPases (V-ATPases) are ATP-powered proton pumps involved in processes such as endocytosis, lysosomal degradation, secondary transport, TOR signalling, and osteoclast and kidney function. ATP hydrolysis in the soluble catalytic V1 region drives proton translocation through the membrane-embedded VO region via rotation of a rotor subcomplex. Variability in the structure of the intact enzyme has prevented construction of an atomic model for the membrane-embedded motor of any rotary ATPase. We induced dissociation and auto-inhibition of the V1 and VO regions of the V-ATPase by starving the yeast Saccharomyces cerevisiae, allowing us to obtain a ~3...
October 24, 2016: Nature
Anusha Mishra, James P Reynolds, Yang Chen, Alexander V Gourine, Dmitri A Rusakov, David Attwell
Active neurons increase their energy supply by dilating nearby arterioles and capillaries. This neurovascular coupling underlies blood oxygen level-dependent functional imaging signals, but its mechanism is controversial. Canonically, neurons release glutamate to activate metabotropic glutamate receptor 5 (mGluR5) on astrocytes, evoking Ca(2+) release from internal stores, activating phospholipase A2 and generating vasodilatory arachidonic acid derivatives. However, adult astrocytes lack mGluR5, and knockout of the inositol 1,4,5-trisphosphate receptors that release Ca(2+) from stores does not affect neurovascular coupling...
October 24, 2016: Nature Neuroscience
Shijiao Han, Jiang Cheng, Huidong Fan, Junsheng Yu, Lu Li
High-response organic field-effect transistor (OFET)-based NO₂ sensors were fabricated using the synergistic effect the synergistic effect of zinc oxide/poly(methyl methacrylate) (ZnO/PMMA) hybrid dielectric and CuPc/Pentacene heterojunction. Compared with the OFET sensors without synergistic effect, the fabricated OFET sensors showed a remarkable shift of saturation current, field-effect mobility and threshold voltage when exposed to various concentrations of NO₂ analyte. Moreover, after being stored in atmosphere for 30 days, the variation of saturation current increased more than 10 folds at 0...
October 21, 2016: Sensors
Sung-Jin Jung, Seong-Kwan Hong, Oh-Kyong Kwon
A readout integrated circuit (ROIC) using two-step fastest signal identification (FSI) is proposed to reduce the number of input channels of a data acquisition (DAQ) block with a high-channel reduction ratio. The two-step FSI enables the proposed ROIC to filter out useless input signals that arise from scattering and electrical noise without using complex and bulky circuits. In addition, an asynchronous fastest signal identifier and a self-trimmed comparator are proposed to identify the fastest signal without using a high-frequency clock and to reduce misidentification, respectively...
October 20, 2016: Sensors
Cristian Axenie, Christoph Richter, Jörg Conradt
Biological and technical systems operate in a rich multimodal environment. Due to the diversity of incoming sensory streams a system perceives and the variety of motor capabilities a system exhibits there is no single representation and no singular unambiguous interpretation of such a complex scene. In this work we propose a novel sensory processing architecture, inspired by the distributed macro-architecture of the mammalian cortex. The underlying computation is performed by a network of computational maps, each representing a different sensory quantity...
October 20, 2016: Sensors
Ali Fatih Demir, Qammer Abbasi, Zekeriyya Esat Ankarali, Akram Alomainy, Khalid Qaraqe, Erchin Serpedin, Huseyin Arslan
In vivo wireless body area networks (WBANs) and their associated technologies are shaping the future of healthcare by providing continuous health monitoring and noninvasive surgical capabilities, in addition to remote diagnostic and treatment of diseases. To fully exploit the potential of such devices, it is necessary to characterize the communication channel which will help to build reliable and high-performance communication systems. This paper presents an in vivo wireless communication channel characterization for male torso both numerically and experimentally (on a human cadaver) considering various organs at 915 MHz and 2...
October 19, 2016: IEEE Journal of Biomedical and Health Informatics
Puneet Manocha, Gitanjali Chandwani, Soumen Das
With current research focus to interconnect the molecular communication environment with external environment, it is imperative to design external devices working on molecular communication schemes to be interfaced with in-vivo molecular network. Recently, efforts have been made to integrate molecular communication with Lab-on-chip (LOC); one of the techniques used in LOC for manipulation and transportation of molecules is Dielectrophoresis (DEP). We propose the use of DEP in molecular communication to maintain in-sequence delivery of molecules...
October 19, 2016: IEEE Transactions on Nanobioscience
Tarak Karmakar, Sundaram Balasubramanian
Arylmalonate decarboxylase (AMDase) catalyzes the decarboxylation of α-aryl-α-methyl malonates to produce optically pure α-arylpropionates of industrial and medicinal importance. Herein, atomistic molecular dynamics simulations have been carried out to delineate the mechanism of the release of product molecules, phenylacetate (PAC) and carbon dioxide (CO2 ) from the wild-type (WT) and its G74C/C188S mutant enzymes. Both the product molecules follow a crystallographically characterized solvent-accessible channel to come out of the protein interior...
October 24, 2016: Journal of Physical Chemistry. B
Lydia Sauer, Sven Peters, Johanna Schmidt, Dietrich Schweitzer, Matthias Klemm, Lisa Ramm, Regine Augsten, Martin Hammer
PURPOSE: To investigate the impact of macular pigment (MP) on fundus autofluorescence (FAF) lifetimes in vivo by characterizing full-thickness idiopathic macular holes (MH) and macular pseudo-holes (MPH). METHODS: A total of 37 patients with MH and 52 with MPH were included. Using the fluorescence lifetime imaging ophthalmoscope (FLIO), based on a Heidelberg Engineering Spectralis system, a 30° retinal field was investigated. FAF decays were detected in a short (498-560 nm; ch1) and long (560-720 nm; ch2) wavelength channel...
October 24, 2016: Acta Ophthalmologica
Raj Kumar Koninti, Sandeep Palvai, Sagar Satpathi, Sudipta Basu, Partha Hazra
Mesoporous silica nano-channel (MCM-41) based molecular switching of a biologically important anticancer drug, namely, ellipticine (EPT) has been utilized to probe its efficient loading onto MCM-41, and its subsequent release to intra-cellular biomolecules, like DNA. By exploiting various spectroscopic techniques (like, steady state fluorescence, time-resolved fluorescence and circular dichroism), it has been shown that EPT can be easily translocated from MCM-41 to DNA without using any external stimulant. Blue emission of EPT in a polar aprotic solvent, i...
October 24, 2016: Nanoscale
Yan Qu, Qiu Gen Zhang, Faizal Soyekwo, Run Sheng Gao, Rui Xue Lv, Chen Xiao Lin, Meng Meng Chen, Ai Mei Zhu, Qing Lin Liu
Two-dimensional nanosheets of late show great promise as novel materials for size-selective separation membranes of high efficiency. Herein, we demonstrate a novel laminated nanofiltration membrane for fast water purification and organic solvent nanofiltration using the 1 nm-thick and 50 nm-wide nickel hydroxide nanosheets that are facilely prepared by a green chemistry method. The resulting membranes exhibit uniform and flectional two-dimensional laminated structure. With about 1 nm high laminated channels, they allow super-fast transport of water and organic solvents...
October 24, 2016: Nanoscale
Kai Zhao, Ran Peng, Dongqing Li
A novel DC-dielectrophoresis (DEP) method employing a pressure-driven flow for the continuous separation of micro/nano-particles is presented in this paper. To generate the DEP force, a small voltage difference is applied to produce a non-uniformity of the electric field across a microchannel via a larger orifice of several hundred microns on one side of the channel wall and a smaller orifice of several hundred nanometers on the opposite channel wall. The particles experience a DEP force when they move with the flow through the vicinity of the small orifice, where the strongest electrical field gradient exists...
October 24, 2016: Nanoscale
Pavel Zelenovskiy, Igor Kornev, Semen Vasilev, Andrei Kholkin
The elastic properties of the nanotubes of self-assembled aromatic dipeptide diphenylalanine are investigated by means of Raman spectroscopy and a mass-in-mass 1D model. Analysis of nanotubes' lattice vibrations reveals the essential contribution of the water in the nanochannel core of the tubes to the Young's modulus and high water mobility along the channel. Direct measurements of the Young's modulus performed by nanoindentation confirm the obtained results.
October 24, 2016: Physical Chemistry Chemical Physics: PCCP
Tian Zhang, Yuan-Yuan Qi, Xiang-Rong Chen, Ling-Cang Cai
Chemical functionalization is an effective means of tuning the electronic and crystal structure of a two-dimensional material, but very little is known regarding the correlation between thermal transport and chemical functionalization. Based on the first-principles calculation and an iterative solution of the Boltzmann transport equation, we find that antimonene is a potential excellent thermal material with relatively low thermal conductivity k, and furthermore, chemical functionalization can make this value of k decrease greatly...
October 24, 2016: Physical Chemistry Chemical Physics: PCCP
Hongming Lyu, Qi Lu, Jinbiao Liu, Xiaoming Wu, Jinyu Zhang, Junfeng Li, Jiebin Niu, Zhiping Yu, Huaqiang Wu, He Qian
In order to conquer the short-channel effects that limit conventional ultra-scale semiconductor devices, two-dimensional materials, as an option of ultimate thin channels, receive wide attention. Graphene, in particular, bears great expectations because of its supreme carrier mobility and saturation velocity. However, its main disadvantage, the lack of bandgap, has not been satisfactorily solved. As a result, maximum oscillation frequency (fmax) which indicates transistors' power amplification ability has been disappointing...
October 24, 2016: Scientific Reports
Fei Yan, Bin Su
Antioxidants are widely found or used in food, pharmaceutical and cosmetics industries, thus rapid and sensitive detection of antioxidants is of great interest. The present work reports a simple and fast electrochemical method for direct analysis of antioxidants in fruit juices by modulating the permeability of mesochannels on the electrode surface. This goal was achieved by growing vertical silica mesochannel array (SMA) with a channel diameter of 2 ∼ 3 nm on the indium tin oxide (ITO) electrode surface using the cylindrical micelles (CMs) as the template...
October 24, 2016: Analytical Chemistry
Desmond H Y Tse, Christopher J Wiggins, Benedikt A Poser
PURPOSE: In order to fully benefit from the improved signal-to-noise and contrast-to-noise ratios at 9.4T, the challenges of B1+ inhomogeneity and the long acquisition time of high-resolution 2D gradient-recalled echo (GRE) imaging were addressed. THEORY AND METHODS: Flip angle homogenized excitations were achieved by parallel transmission (pTx) of 3-spoke pulses, designed by magnitude least-squares optimization in a slice-by-slice fashion; the acquisition time reduction was achieved by simultaneous multislice (SMS) pulses...
October 23, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Feng Wu, Nan Chen, Renjie Chen, Qizhen Zhu, Guoqiang Tan, Li Li
The lack of suitable nonflammable electrolytes has delayed battery application in electric vehicles. A new approach to improve the safety performance for lithium battery is proposed here. This technology is based on a nanogelator-based solid electrolyte made of porous oxides and an ionic liquid. The electrolyte is fabricated using an in situ method and the porous oxides serve as a nonflammable "nanogelator" that spontaneously immobilizes the ionic liquid. The electrolyte exhibits a high liquid-like apparent ionic conductivity of 2...
January 2016: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Hong-Jie Peng, Dai-Wei Wang, Jia-Qi Huang, Xin-Bing Cheng, Zhe Yuan, Fei Wei, Qiang Zhang
Owing to the conversion chemistry of the sulfur cathode, the lithium-sulfur (Li-S) batteries exhibit high theoretical energy density. However, the intrinsic mobile redox centers during the sulfur/Li2S-to-lithium polysulfides solid-to-liquid phase transition induce low sulfur utilization and poor cycling life. Herein, the Janus separator of mesoporous cellular graphene framework (CGF)/polypropylene membrane to promote the utilization of sulfur cathode is introduced. The porous polypropylene membrane serves as an insulating substrate in contact with lithium anode while CGFs that possess high electrical conductivity of 100 S cm(-1), a large mesopore volume of 3...
January 2016: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Andrew Mezentsev, Nikolai Østgaard, Thomas Gjesteland, Kjetil Albrechtsen, Nikolai Lehtinen, Martino Marisaldi, David Smith, Steven Cummer
A detailed analysis of Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) terrestrial gamma ray flashes (TGFs) is performed in association with World Wide Lightning Location Network (WWLLN) sources and very low frequency (VLF) sferics recorded at Duke University. RHESSI clock offset is evaluated and found to experience changes on the 5 August 2005 and 21 October 2013, based on the analysis of TGF-WWLLN matches. The clock offsets were found for all three periods of observations with standard deviations less than 100 μs...
July 16, 2016: Journal of Geophysical Research. Atmospheres: JGR
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