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Munehiro Inukai, Masanori Tamura, Satoshi Horike, Masakazu Higuchi, Susumu Kitagawa, Koichi Nakamura
Design to store gas molecules, such as CO₂, H₂, and CH₄, under low pressure is one of the most important challenges in chemistry and materials science. Herein, we describe the storage of CO₂ in the cavities of a porous coordination polymer (PCP) using molecular rotor dynamics. Owing to the narrow pore windows of PCP, CO₂ was not adsorbed at 195 K. As the temperature increased, the rotors exhibited rotational modes; such rotations dynamically expanded the size of the windows, leading to CO₂ adsorption...
May 18, 2018: Angewandte Chemie
Shuangzan Lu, Min Huang, Zhihui Qin, Yinghui Yu, Qinmin Guo, Gengyu Cao
Molecular rotors, motors and gears plays important roles in artificial molecular machines, in which rotor and motor matrices are much desirable for large scale bottom-up fabrication of molecular machines. Here we demonstrate the fabrication of a highly ordered molecular rotor matrix by depositing nonplanar dipolar titanyl phthalocyanine (TiOPc, C<sub>32</sub>H<sub>16</sub>N<sub>8</sub>OTi) molecules on Moiré patterned dipolar FeO/Pt(111) substrate...
May 17, 2018: Nanotechnology
Yingying Wu, Guangxia Wang, Qiaolian Li, Junfeng Xiang, Hua Jiang, Ying Wang
Despite having significant applications in building nanomachines, molecular rotors with the rotational speed modulations to multiple stages in a wide range of frequency have not yet been well established. Here, we report the discovery of a stimuli-responsive molecular rotor, the rotational speed of which in the slow-to-fast range could be modulated to at least four stages triggered by acid/base and metal cations. The rotor itself rotates rapidly at ambient or elevated temperature but displays a restricted rotation after deprotonation due to the produced intramolecular electrostatic repulsion...
May 16, 2018: Nature Communications
Xinggui Gu, Xiaoyan Zhang, Huili Ma, Shaorui Jia, Pengfei Zhang, Yanjun Zhao, Qian Liu, Jianguo Wang, Xiaoyan Zheng, Jacky W Y Lam, Dan Ding, Ben Zhong Tang
Fluorescent nanoparticles (NPs) based on luminogens with aggregation-induced emission characteristic (AIEgens), namely AIE dots, have received wide attention because of their antiquenching attitude in emission and reactive oxygen species (ROS) generation when aggregated. However, few reports are available on how to control and optimize their fluorescence and ROS generation ability. Herein, it is reported that enhancing the intraparticle confined microenvironment is an effective approach to advanced AIE dots, permitting boosted cancer phototheranostics in vivo...
May 16, 2018: Advanced Materials
Suresh K Vasa, Petra Rovó, Rasmus Linser
Solid-state nuclear magnetic resonance (ssNMR) is a spectroscopic technique that is used for characterization of molecular properties in the solid phase at atomic resolution. In particular, using the approach of magic-angle spinning (MAS), ssNMR has seen widespread applications for topics ranging from material sciences to catalysis, metabolomics, and structural biology, where both isotropic and anisotropic parameters can be exploited for a detailed assessment of molecular properties. High-resolution detection of protons long represented the holy grail of the field...
May 15, 2018: Accounts of Chemical Research
Koray Sekeroglu, C W Extrand, David A Burdge
The onset of drainage of liquids from plastic tubes was evaluated. One end of the tubes was plugged, filled with liquid, oriented horizontally, and attached to a rotor. With their open end facing outward, the filled tubes were spun at progressively higher speeds until they began to drain. Resistance to drainage was independent of the tube length, but depended on the surface tension and density of the liquids as well as the diameter and wettability of the tubing. We found that the onset of drainage could be explained in terms of a critical centrifugal acceleration...
May 15, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
James L Martin, Robert Ishmukhametov, David Spetzler, Tassilo Hornung, Wayne D Frasch
The angular velocity profile of the 120° F1 -ATPase power stroke was resolved as a function of temperature from 16.3 to 44.6 °C using a ΔμATP = -31.25 k B T at a time resolution of 10 μs. Angular velocities during the first 60° of the power stroke (phase 1) varied inversely with temperature, resulting in negative activation energies with a parabolic dependence. This is direct evidence that phase 1 rotation derives from elastic energy (spring constant, κ = 50 k B T ·rad-2 ). Phase 2 of the power stroke had an enthalpic component indicating that additional energy input occurred to enable the γ-subunit to overcome energy stored by the spring after rotating beyond its 34° equilibrium position...
May 14, 2018: Proceedings of the National Academy of Sciences of the United States of America
Tayler L Williams, Gary E Gorbet, Borries Demeler
Recent developments in the UltraScan-III software make it possible to model multi-speed analytical ultracentrifugation sedimentation velocity experiments using finite-element solutions of the Lamm equation. Using simulated data, we demonstrate here how these innovations can be used to enhance the resolution of sedimentation velocity experiments when compared to single-speed experiments. Using heterogeneous systems covering as much as five orders of magnitude in molar mass and fivefold in anisotropy, we compare results from runs performed at multiple speeds to those obtained from single-speed experiments, fitted individually and analyzed globally over multiple speeds, and quantify resolution for sample heterogeneous in size and anisotropy...
May 10, 2018: European Biophysics Journal: EBJ
Alexander Hahn, Janet Vonck, Deryck J Mills, Thomas Meier, Werner Kühlbrandt
The chloroplast adenosine triphosphate (ATP) synthase uses the electrochemical proton gradient generated by photosynthesis to produce ATP, the energy currency of all cells. Protons conducted through the membrane-embedded Fo motor drive ATP synthesis in the F1 head by rotary catalysis. We determined the high-resolution structure of the complete cF1 Fo complex by cryo-electron microscopy, resolving side chains of all 26 protein subunits, the five nucleotides in the F1 head, and the proton pathway to and from the rotor ring...
May 11, 2018: Science
Fuyuan Xiao, Bowen Qin
Dempster⁻Shafer evidence theory is widely applied in various fields related to information fusion. However, how to avoid the counter-intuitive results is an open issue when combining highly conflicting pieces of evidence. In order to handle such a problem, a weighted combination method for conflicting pieces of evidence in multi-sensor data fusion is proposed by considering both the interplay between the pieces of evidence and the impacts of the pieces of evidence themselves. First, the degree of credibility of the evidence is determined on the basis of the modified cosine similarity measure of basic probability assignment...
May 9, 2018: Sensors
Charles Houston, Konstantinos N Tzortzis, Caroline Roney, Andrea Saglietto, David S Pitcher, Chris Cantwell, Rasheda A Chowdhury, Fu Siong Ng, Nicholas S Peters, Emmanuel Dupont
Fibrillation is the most common arrhythmia observed in clinical practice. Understanding of the mechanisms underlying its initiation and maintenance remains incomplete. Functional re-entries are potential drivers of the arrhythmia. Two main concepts are still debated, the "leading circle" and the "spiral wave or rotor" theories. The homogeneous subclone of the HL1 atrial-derived cardiomyocyte cell line, HL1-6, spontaneously exhibits re-entry on a microscopic scale due to its slow conduction velocity and the presence of triggers, making it possible to examine re-entry at the cellular level...
May 7, 2018: Journal of Molecular and Cellular Cardiology
Barbara Bellmann, Tina Lin, Peter Ruppersberg, Marit Zettwitz, Selma Guttmann, Verena Tscholl, Patrick Nagel, Mattias Roser, Ulf Landmesser, Andreas Rillig
BACKGROUND: The optimal ablation approach for the treatment of persistent atrial fibrillation (AF) is still under debate; however, the identification and elimination of AF sources is thought to play a key role. Currently available technologies for the identification of AF sources are not able to differentiate between active rotors or focal impulse (FI) and passive circular turbulences as generated by the interaction of a wave front with a functional obstacle such as fibrotic tissue. OBJECTIVES: This study introduces electrographic flow (EGF) mapping as a novel technology for the identification and characterization of AF sources in humans...
May 9, 2018: Clinical Research in Cardiology: Official Journal of the German Cardiac Society
Tina Baykaner, Albert J Rogers, Gabriela L Meckler, Junaid Zaman, Rachita Navara, Miguel Rodrigo, Mahmood Alhusseini, Christopher A B Kowalewski, Mohan N Viswanathan, Sanjiv M Narayan, Paul Clopton, Paul J Wang, Paul A Heidenreich
BACKGROUND: The outcomes from pulmonary vein isolation (PVI) for atrial fibrillation (AF) are suboptimal, but the benefits of additional lesion sets remain unproven. Recent studies propose ablation of AF drivers improves outcomes over PVI, yet with conflicting reports in the literature. We undertook a systematic literature review and meta-analysis to determine outcomes from ablation of AF drivers in addition to PVI or as a stand-alone procedure. METHODS: Database search was done using the terms atrial fibrillation and ablation or catheter ablation and driver or rotor or focal impulse or FIRM (Focal Impulse and Rotor Modulation)...
May 2018: Circulation. Arrhythmia and Electrophysiology
Dongyu Gu, Rodrigo Lazo-Portugal, Chen Fang, Zhantong Wang, Ying Ma, Martha Knight, Yoichiro Ito
Centrifugal precipitation chromatography (CpC) is a powerful chromatographic technique invented in the year 2000 but so far very little applied. The method combines dialysis, counter-current and salting out processes. The separation rotor consists of two identical spiral channels separated by a dialysis membrane (6-8 K MW cut-off) in which the upper channel is eluted with an ammonium sulfate gradient and the lower channel with water, and the mixtures are separated according to their solubility in ammonium sulfate as a chromatographic technique...
May 1, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Yingxiang Liu, Yun Wang, Junkao Liu, Dongmei Xu, Kai Li, Xiaobiao Shan, Jie Deng
A four-feet walking-type rotary piezoelectric actuator with minute step motion was proposed. The proposed actuator used the rectangular motions of four driving feet to push the rotor step-by-step; this operating principle was different with the previous non-resonant actuators using direct-driving, inertial-driving, and inchworm-type mechanisms. The mechanism of the proposed actuator was discussed in detail. Transient analyses were accomplished by ANSYS software to simulate the motion trajectory of the driving foot and to find the response characteristics...
May 8, 2018: Sensors
Sergey Simonov, Leokadiya Zorina, Pawel Wzietek, Antonio Rodríguez-Fortea, Enric Canadell, Cécile Mézière, Guillaume Bastien, Cyprien Lemouchi, Miguel A Garcia-Garibay, Patrick Roger Batail
Here we present a study where what can be seen as a static modulation wave encompassing four successive arrays of interacting iodine atoms in crystalline 1,4-Bis((4'-(iodoethynyl)phenyl) ethynyl)bicyclo[2,2,2]octane rotors changes the structure from one-half molecule to three-and-a-half molecules in the asymmetric unit below a phase transition at 105 K. The remarkable finding is that the total 1H spin-lattice relaxation rate, T1-1, of unprecedented complexity to date in molecular rotors, is the weighted sum of the relaxation rates of the four contributing rotors relaxation rates, each with distinguishable exchange frequencies reflecting Arrhenius parameters with different activation barriers (Ea) and attempt frequencies (tauo-1)...
May 8, 2018: Nano Letters
Helen Hencida Thangamony, Ravindran Kumar, Chinnappan Palaniappan Thangavelu, Mani Mariappa, Berlin Grace Viswanathan Mariammal, Kootallur Narayanan Brahmadathan
Background: Determination of various analytical parameters is essential for the validation of primers used for in-house nucleic acid amplification tests. While standardising a high-resolution melt analysis (HRMA) for detection of Streptococcus pneumoniae in acute pyogenic meningitis, we encountered non-specific amplification of certain base pair sequences of human DNA by Centers for Disease Control & Prevention, USA recommended S. pneumoniae LytA primer. Materials and Methods: HRMA was standardised using DNA extracted from an ATCC strain of S...
January 2018: Indian Journal of Medical Microbiology
Sheng Guo, Tao Yang, Wei Gao, Chen Zhang
Fault diagnosis is critical to ensure the safety and reliable operation of rotating machinery. Most methods used in fault diagnosis of rotating machinery extract a few feature values from vibration signals for fault diagnosis, which is a dimensionality reduction from the original signal and may omit some important fault messages in the original signal. Thus, a novel diagnosis method is proposed involving the use of a convolutional neural network (CNN) to directly classify the continuous wavelet transform scalogram (CWTS), which is a time-frequency domain transform of the original signal and can contain most of the information of the vibration signals...
May 4, 2018: Sensors
Tarek Ameid, Arezki Menacer, Hicham Talhaoui, Youness Azzoug
This paper presents a methodology for the broken rotor bars fault detection is considered when the rotor speed varies continuously and the induction machine is controlled by Field-Oriented Control (FOC). The rotor fault detection is obtained by analyzing a several mechanical and electrical quantities (i.e., rotor speed, stator phase current and output signal of the speed regulator) by the Discrete Wavelet Transform (DWT) in variable speed drives. The severity of the fault is obtained by stored energy calculation for active power signal...
May 3, 2018: ISA Transactions
Zachary R Kehoe, Garrett R Woller, Erin D Speetzen, James B Lawrence, Eric Bosch, Nathan P Bowling
The electronic properties of a pyrazine-containing arylene ethynylene unit are influenced by hydrogen bond and halogen bond donors that are held in proximity of the pyrazine rotor. These interactions are evident with iodine and bromine centered halogen bonds and O-H and C-H based hydrogen bonds. Bathochromic shifts of UV-vis and fluorescence signals are the best indicators of this intramolecular attraction. The effects can be attenuated in solvents that are less favorable for intramolecular halogen or hydrogen bonding, such as 2-propanol, and amplified in solvents that are supportive, such as toluene...
May 4, 2018: Journal of Organic Chemistry
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