keyword
MENU ▼
Read by QxMD icon Read
search

Rotor

keyword
https://www.readbyqxmd.com/read/28229262/on-the-use-of-ultracentrifugal-devices-for-routine-sample-preparation-in-biomolecular-magic-angle-spinning-nmr
#1
Abhishek Mandal, Jennifer C Boatz, Travis B Wheeler, Patrick C A van der Wel
A number of recent advances in the field of magic-angle-spinning (MAS) solid-state NMR have enabled its application to a range of biological systems of ever increasing complexity. To retain biological relevance, these samples are increasingly studied in a hydrated state. At the same time, experimental feasibility requires the sample preparation process to attain a high sample concentration within the final MAS rotor. We discuss these considerations, and how they have led to a number of different approaches to MAS NMR sample preparation...
February 22, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28227287/identification-and-annotation-of-multiple-periodic-pulse-trains-using-dominant-frequency-and-graph-search-applications-in-atrial-fibrillation-rotor-detection
#2
Rupin Dalvi, Adrian Suszko, Vijay S Chauhan, Rupin Dalvi, Adrian Suszko, Vijay S Chauhan, Rupin Dalvi, Adrian Suszko, Vijay S Chauhan
Biological signals, such as intracardiac electrograms during atrial fibrillation (AF), can contain multiple periodic components or peaks. We propose a method for identifying individual periodic peak trains in signals containing multiple such periodic sequences. We use dominant frequency-based periodicity detection along with a graph search algorithm to identify the most dominant periodic activation set or peaks of interest. We then remove these peaks and iterate until all periodic sequences are identified. The proposed method is tested on simulated AF intra-cardiac electrograms with periodic activation trains of three distinct frequencies corrupted by noise and complex aperiodic signal features...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227263/an-algorithm-for-rotor-tracking-in-atrial-fibrillation-using-graph-search-based-periodic-peak-detection
#3
Rupin Dalvi, Adrian Suszko, Vijay S Chauhan, Rupin Dalvi, Adrian Suszko, Vijay S Chauhan, Rupin Dalvi, Adrian Suszko, Vijay S Chauhan
Rotors are rotating electrical waves that may sustain atrial fibrillation (AF); thereby providing therapeutic targets for catheter ablation. We propose a method for identifying rotors from circular catheter recordings of bipolar intracardiac electrograms (EGM) during AF. We use dominant frequency-based periodicity detection along with a graph search algorithm to identify the most dominant periodic activations or peaks of interest in each bipolar EGM recorded by a multipolar circular catheter. We then track the activations across catheter bipoles to determine whether they conform to the rotational pattern of a rotor...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226545/a-novel-catheter-guidance-algorithm-for-localization-of-atrial-fibrillation-rotor-and-focal-sources
#4
Anthony J Salmin, Prasanth Ganesan, Kristina E Shillieto, Elizabeth M Cherry, David T Huang, Arkady M Pertsov, Behnaz Ghoraani, Anthony J Salmin, Prasanth Ganesan, Kristina E Shillieto, Elizabeth M Cherry, David T Huang, Arkady M Pertsov, Behnaz Ghoraani, Arkady M Pertsov, Behnaz Ghoraani, Anthony J Salmin, Kristina E Shillieto, Elizabeth M Cherry, Prasanth Ganesan, David T Huang
Locating atrial fibrillation (AF) focal and rotor sources can help improve target ablation therapy for AF. However, it remains unclear how to use the information provided by multi-polar diagnostic catheters (MPDC) to locate AF sources. Our aim was to develop a catheter-guidance algorithm to locate AF focal and rotor sources using a conventional MPDC. We simulated a 10 cm × 10 cm atrial tissue with focal and rotor sources using the Nygren et al. ionic model. We modeled a Lasso MPDC with 20-unipole electrodes placed with a spacing of 4...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226544/kurtosis-as-a-statistical-approach-to-identify-the-pivot-point-of-the-rotor
#5
Shivaram P Arunachalam, Elizabeth M Annoni, Siva K Mulpuru, Paul A Friedman, Elena G Tolkacheva, Shivaram P Arunachalam, Elizabeth M Annoni, Siva K Mulpuru, Paul A Friedman, Elena G Tolkacheva, Elena G Tolkacheva, Paul A Friedman, Elizabeth M Annoni, Siva K Mulpuru, Shivaram P Arunachalam
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia that causes stroke affecting more than 2.3 million people in the US. Catheter ablation to terminate AF is successful for paroxysmal AF but suffers limitations with persistent AF patients as current mapping methods cannot identify AF active substrates outside of pulmonary vein region. In this work, we developed a novel Kurtosis based mapping technique that can accurately identify pivot points of the rotors that were induced in ex-vivo isolated rabbit heart...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226543/development-of-a-novel-probabilistic-algorithm-for-localization-of-rotors-during-atrial-fibrillation
#6
Prasanth Ganesan, Anthony Salmin, Elizabeth M Cherry, Behnaz Ghoraani, Prasanth Ganesan, Anthony Salmin, Elizabeth M Cherry, Behnaz Ghoraani, Elizabeth M Cherry, Prasanth Ganesan, Behnaz Ghoraani, Anthony Salmin
Atrial fibrillation (AF) is an irregular heart rhythm that can lead to stroke and other heart-related complications. Catheter ablation has been commonly used to destroy triggering sources of AF in the atria and consequently terminate the arrhythmia. However, efficient and accurate localization of the AF sustaining sources known as rotors is a major challenge in catheter ablation. In this paper, we developed a novel probabilistic algorithm that can adaptively guide a Lasso diagnostic catheter to locate the center of a rotor...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225281/hydrogen-abstraction-from-hydrocarbons-by-nh2
#7
Kamal Siddique, Mohammednoor K Altarawneh, Jeff Gore, Phillip R Westmoreland, Bogdan Z Dlugogorski
This contribution investigates thermokinetic parameters of bimolecular gas-phase reactions involving the amine (NH2) radical and a large number of saturated and unsaturated hydrocarbons. These reactions play an important role in combustion and pyrolysis of nitrogen-rich fuels, most notably biomass. Computations performed at the CBS-QB3 level and based on the conventional transition-state theory yield potential-energy surfaces and reaction rate constants, accounting for tunnelling effects and the presence of hindered rotors...
February 22, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28218316/theoretical-study-of-hcn-water-interaction-five-dimensional-potential-energy-surfaces
#8
Ernesto Quintas Sánchez, Marie-Lise Dubernet
A new five-dimensional potential energy surface is calculated at the coupled-cluster CCSD(T) level of theory for the HCN-water system, treating both monomers as rigid rotors. The associated methodology, which combines extensive ab initio calculations of moderate accuracy (CCSD(T)/AVDZ) and a fitting procedure involving a much lower angular coverage with more accurate ab initio calculations (CCSD(T)/CBS), is described in detail. This methodology provides a time-saving approach to compute quantitatively accurate potential energy surfaces with reasonable computational effort...
February 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28216586/state-space-formulation-of-nonlinear-vibration-responses-collected-from-a-dynamic-rotor-bearing-system-an-extension-of-bearing-diagnostics-to-bearing-prognostics
#9
Peter W Tse, Dong Wang
Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL)...
February 14, 2017: Sensors
https://www.readbyqxmd.com/read/28215065/application-of-computer-models-on-atrial-fibrillation-research
#10
Michela Masè
Atrial fibrillation (AF) is a multifactorial and multiscale disease, where electrical, structural, anatomical and genetic factors contribute to the emergence of a complex and dynamic macroscopic phenotype. The incomplete understanding of AF mechanisms and the diversity and multiplicity of factors promoting the arrhythmia in humans have hampered the development of effective therapeutic approaches. Computer models and simulation of atrial arrhythmias may represent an unique allied to investigate AF mechanisms and direct therapeutic strategies, being able to merge and provide interpretation for multiscale data from cellular to entire organ scale levels...
February 17, 2017: Minerva Cardioangiologica
https://www.readbyqxmd.com/read/28213506/role-of-apamin-sensitive-calcium-activated-small-conductance-potassium-currents-on-the-mechanisms-of-ventricular-fibrillation-in-pacing-induced-failing-rabbit-hearts
#11
Dechun Yin, Yu-Cheng Hsieh, Wei-Chung Tsai, Adonis Zhi-Yang Wu, Zhaolei Jiang, Yi-Hsin Chan, Dongzhu Xu, Na Yang, Changyu Shen, Zhenhui Chen, Shien-Fong Lin, Peng-Sheng Chen, Thomas H Everett
BACKGROUND: Ventricular fibrillation (VF) during heart failure is characterized by stable reentrant spiral waves (rotors). Apamin-sensitive small-conductance calcium-activated potassium currents (IKAS) are heterogeneously upregulated in failing hearts. We hypothesized that IKAS influences the location and stability of rotors during VF. METHODS AND RESULTS: Optical mapping was performed on 9 rabbit hearts with pacing-induced heart failure. The epicardial right ventricular and left ventricular surfaces were simultaneously mapped in a Langendorff preparation...
February 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28212459/structural-studies-of-nicotinoids-cotinine-vs-nicotine
#12
Iciar Uriarte, Cristóbal Pérez, Elena Caballero-Mancebo, Francisco J Basterretxea, Alberto Lesarri, José A Fernández, Emilio J Cocinero
Nicotinoids are agonists of the acetylcholine receptor (nAChR) and play important biochemical and pharmacological roles. Here we report on the structural and conformational landscape of cotinine, and compare its molecular properties with the nicotine prototype, from which it only differs in the addition of a carbonyl group. The investigation of cotinine included a theoretical survey of the effects of rotamerization of the pyridine moiety, the puckering of the pyrrolidinone ring and the internal rotation of the methyl group...
February 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28201894/manipulating-and-probing-the-polarisation-of-a-methyl-tunnelling-system-by-field-cycling-nmr
#13
Bo Zhang, Sabah M M Abu-Khumra, Abdellah Aibout, Anthony J Horsewill
In NMR the polarisation of the Zeeman system may be routinely probed and manipulated by applying resonant rf pulses. As with spin-1/2 nuclei, at low temperature the quantum tunnelling states of a methyl rotor are characterised by two energy levels and it is interesting to consider how these tunnelling states might be probed and manipulated in an analogous way to nuclear spins in NMR. In this paper experimental procedures based on magnetic field-cycling NMR are described where, by irradiating methyl tunnelling sidebands, the polarisations of the methyl tunnelling systems are measured and manipulated in a prescribed fashion...
February 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28201883/rotational-excitation-of-the-interstellar-nh2-radical-by-h2
#14
Nezha Bouhafs, François Lique, Alexandre Faure, Aurore Bacmann, Jun Li, Hua Guo
We present quantum close-coupling calculations for the rotational excitation of the interstellar amidogen radical NH2 due to collisions with H2 molecules. The calculations are based on a recent, high-accuracy full-dimensional NH4 potential energy surface adapted for rigid-rotor scattering calculations. The collisional cross section calculations are performed for all transitions among the first 15 energy levels of both ortho- and para-NH2 and for total energies up to 1500 cm(-1). Both para- and ortho-H2 colliding partners are considered...
February 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28199775/a-photoregulated-dna-based-rotary-system-and-direct-observation-of-its-rotational-movement
#15
Yangyang Yang, Ryu Tashiro, Yuki Suzuki, Tomoko Emura, Kumi Hidaka, Hiroshi Sugiyama, Masayuki Endo
Various DNA-based nanodevices have been developed on the nanometer scale using light as regulation input. However, the programmed controllability is still a major challenge for these artificial nanodevices. Herein, we demonstrate a rotary DNA nanostructure in which the rotations are controlled by light. A bar-shaped DNA rotor, fabricated as a stiff double-crossover molecule, was placed on the top of a rectangular DNA tile. The photoresponsive oligonucleotides modified with azobenzenes were employed as switching motifs to release/trap the rotor at specific angular position on DNA tile by switching photoirradiations between ultraviolet and visible light...
February 15, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28198115/double-stranded-helical-oligomers-covalently-bridged-by-rotary-cyclic-boronate-esters
#16
Hiroki Iida, Kenji Ohmura, Ryuta Noda, Soichiro Iwahana, Hiroshi Katagiri, Naoki Ousaka, Taku Hayashi, Yuh Hijikata, Stephan Irle, Eiji Yashima
Novel double helices covalently-bridged by cyclic boronate esters were synthesized from complementary dimers with a m-terphenyl backbone joined by a chiral or achiral phenylene linker bearing diethyl boronates and diols, respectively. The X-ray crystallographic analysis and variable-temperature NMR and circular dichroism measurements, along theoretical calculations, revealed that the double helices function as a "molecular rotor" in which the cyclic boronate ester units rotate, yielding two stable rotamers at low temperatures...
February 14, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28182561/decomposition-of-rotor-hopfield-neural-networks-using-complex-numbers
#17
Masaki Kobayashi
A complex-valued Hopfield neural network (CHNN) is a multistate model of a Hopfield neural network. It has the disadvantage of low noise tolerance. Meanwhile, a symmetric CHNN (SCHNN) is a modification of a CHNN that improves noise tolerance. Furthermore, a rotor Hopfield neural network (RHNN) is an extension of a CHNN. It has twice the storage capacity of CHNNs and SCHNNs, and much better noise tolerance than CHNNs, although it requires twice many connection parameters. In this brief, we investigate the relations between CHNN, SCHNN, and RHNN; an RHNN is uniquely decomposed into a CHNN and SCHNN...
February 2, 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28176770/metal-centred-azaphosphatriptycene-gear-with-a-photo-and-thermally-driven-mechanical-switching-function-based-on-coordination-isomerism
#18
Hitoshi Ube, Yoshihiro Yasuda, Hiroyasu Sato, Mitsuhiko Shionoya
Metal ions can serve as a centre of molecular motions due to their coordination geometry, reversible bonding nature and external stimuli responsiveness. Such essential features of metal ions have been utilized for metal-mediated molecular machines with the ability to motion switch via metallation/demetallation or coordination number variation at the metal centre; however, motion switching based on the change in coordination geometry remain largely unexplored. Herein, we report a Pt(II)-centred molecular gear that demonstrates control of rotor engagement and disengagement based on photo- and thermally driven cis-trans isomerization at the Pt(II) centre...
February 8, 2017: Nature Communications
https://www.readbyqxmd.com/read/28157349/experimental-demonstration-of-coherent-control-in-quantum-chaotic-systems
#19
M Bitter, V Milner
We experimentally demonstrate coherent control of a quantum system, whose dynamics is chaotic in the classical limit. Interaction of diatomic molecules with a periodic sequence of ultrashort laser pulses leads to the dynamical localization of the molecular angular momentum, a characteristic feature of the chaotic quantum kicked rotor. By changing the phases of the rotational states in the initially prepared coherent wave packet, we control the rotational distribution of the final localized state and its total energy...
January 20, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28157341/are-there-signatures-of-harmonic-oscillator-shells-far-from-stability-first-spectroscopy-of-110-zr
#20
N Paul, A Corsi, A Obertelli, P Doornenbal, G Authelet, H Baba, B Bally, M Bender, D Calvet, F Château, S Chen, J-P Delaroche, A Delbart, J-M Gheller, A Giganon, A Gillibert, M Girod, P-H Heenen, V Lapoux, J Libert, T Motobayashi, M Niikura, T Otsuka, T R Rodríguez, J-Y Roussé, H Sakurai, C Santamaria, N Shimizu, D Steppenbeck, R Taniuchi, T Togashi, Y Tsunoda, T Uesaka, T Ando, T Arici, A Blazhev, F Browne, A M Bruce, R Carroll, L X Chung, M L Cortés, M Dewald, B Ding, F Flavigny, S Franchoo, M Górska, A Gottardo, A Jungclaus, J Lee, M Lettmann, B D Linh, J Liu, Z Liu, C Lizarazo, S Momiyama, K Moschner, S Nagamine, N Nakatsuka, C Nita, C R Nobs, L Olivier, Z Patel, Zs Podolyák, M Rudigier, T Saito, C Shand, P-A Söderström, I Stefan, R Orlandi, V Vaquero, V Werner, K Wimmer, Z Xu
The first measurement of the low-lying states of the neutron-rich ^{110}Zr and ^{112}Mo was performed via in-beam γ-ray spectroscopy after one proton removal on hydrogen at ∼200  MeV/nucleon. The 2_{1}^{+} excitation energies were found at 185(11) keV in ^{110}Zr, and 235(7) keV in ^{112}Mo, while the R_{42}=E(4_{1}^{+})/E(2_{1}^{+}) ratios are 3.1(2), close to the rigid rotor value, and 2.7(1), respectively. These results are compared to modern energy density functional based configuration mixing models using Gogny and Skyrme effective interactions...
January 20, 2017: Physical Review Letters
keyword
keyword
107224
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"