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Sanghamitra Mohanty, Prasant Mohanty, Chintan Trivedi, Carola Gianni, Domenico G Della Rocca, Luigi Di Biase, Andrea Natale
BACKGROUND: This meta-analysis systematically evaluated the outcome of pulmonary vein isolation (PVI) with and without focal impulse and rotor modulation (FIRM) ablation in patients with atrial fibrillation. METHODS AND RESULTS: Extensive literature search was performed for studies reporting outcomes of PVI alone and PVI+FIRM procedures. For PVI alone, only randomized trials conducted in the past 3 years reporting single-procedure off-antiarrhythmic drugs success rate at ≥12-month follow-up were included...
March 2018: Circulation. Arrhythmia and Electrophysiology
B P Abolins, R E Zillich, K B Whaley
The quantum phase transitions of dipoles confined to the vertices of two-dimensional lattices of square and triangular geometry is studied using path integral ground state quantum Monte Carlo. We analyze the phase diagram as a function of the strength of both the dipolar interaction and a transverse electric field. The study reveals the existence of a class of orientational phases of quantum dipolar rotors whose properties are determined by the ratios between the strength of the anisotropic dipole-dipole interaction, the strength of the applied transverse field, and the rotational constant...
March 14, 2018: Journal of Chemical Physics
Michael M Linden, J Philipp Wagner, Bastian Bernhardt, Marcus A Bartlett, Wesley D Allen, Peter R Schreiner
Disentangling internal and external effects is a key requirement for understanding conformational tunneling processes. Here we report the s-trans/s-cis tunneling rotamerization of carbonic acid monomethyl ester (1) under matrix isolation conditions and make comparisons to its parent carbonic acid (3). The observed tunneling rate of 1 is temperature independent in the 3-20 K range and accelerates when using argon instead of neon as the matrix material. The methyl group increases the effective half-life (τeff) of the energetically disfavored s-trans-conformer from 3-5 h for 3 to 11-13 h for 1...
March 15, 2018: Journal of Physical Chemistry Letters
Uma Mahesh R Avula, Jonathan J Hernandez, Masatoshi Yamazaki, Carmen R Valdivia, Antony Chu, Alvaro Rojas-Pena, Kuljeet Kaur, Roberto Ramos-Mondragón, Justus M Anumonwo, Stanley Nattel, Héctor H Valdivia, Jérôme Kalifa
BACKGROUND: The mechanisms underlying spontaneous atrial fibrillation (AF) associated with atrial ischemia/infarction are incompletely elucidated. Here, we investigate the mechanisms underlying spontaneous AF in an ovine model of left atrial myocardial infarction (LAMI). METHODS AND RESULTS: LAMI was created by ligating the atrial branch of the left anterior descending coronary artery. ECG loop recorders were implanted to monitor AF episodes. In 7 sheep, dantrolene-a ryanodine receptor blocker-was administered in vivo during the 8-day observation period (LAMI-D, 2...
March 2018: Circulation. Arrhythmia and Electrophysiology
Prajakta Rajaram Parab, K Alexander Heufer, Ravi Xavier Fernandes
Isopentanol is a potential next-generation biofuel for future applications to Homogeneous Charge Compression Ignition (HCCI) engine concepts. To provide insights into the combustion behavior of isopentanol, especially to its auto-ignition behavior which is linked both to efficiency and pollutant formation in real combustion systems, detailed quantum chemical studies for crucial reactions are desired. H-Abstraction reaction rates from fuel molecules are key initiation steps for chain branching required for auto-ignition...
March 13, 2018: Physical Chemistry Chemical Physics: PCCP
Mohie E M Zayed, Reda M El-Shishtawy, Shaaban A Elroby, Khalid O Al-Footy, Zahra M Al-Amshany
A set of different donor-π-acceptor compounds having dicyanovinyl as the acceptor and aryl moieties as donors were synthesized by Knoevenagel condensation. The UV-visible absorption and fluorescence spectra were investigated in different solvents. The optical band gab energy (Eg) was linearly correlated with the Hammett resonance effect of the donor to reveal that the higher the value of Hammett resonance effect of a donor, the lower the Eg of the molecule. The photophysical data revealed that compounds M4-M6 are typical molecular rotors with fluorescence due to twisted intramolecular charge transfer...
March 9, 2018: Chemistry Central Journal
Samah Y Mohamed, Alexander Cory Davis, Mariam J Al Rashidi, S Mani Sarathy
Hydroperoxyalkylperoxy (OOQOOH) radical isomerization is an important low-temperature chain branching reaction within the mechanism of hydrocarbon oxidation. This isomerization may proceed via the migration of the α-hydrogen to the hydroperoxide group. In this work, a combination of high level composite methods - CBS-QB3, G3 and G4 - is used to determine the high-pressure-limit rate parameters for the title reaction. Rate rules for H-migration reactions proceeding through 5-, 6-, 7- and 8-membered ring transitions states are determined...
March 8, 2018: Journal of Physical Chemistry. A
Dmitry Telyshev, Maxim Denisov, Alexander Pugovkin, Sergey Selishchev, Igor Nesterenko
In this work, the study results of an implantable pediatric rotary blood pump (PRBP) are presented. They show the results of the numerical simulation of fluid flow rates in the pump. The determination method of the backflows and stagnation regions is represented. The operating points corresponding to fluid flow rates of 1, 3, and 5 L/min for 75-80 mm Hg pressure head are investigated. The study results have shown that use of the pump in the 1 L/min operating point can potentially lead to the appearance of backflows and stagnation regions...
March 6, 2018: Artificial Organs
Prabhpreet Singh, Amit Noheria
Invasive electrophysiology (EP) mapping and catheter ablation has increasingly become the standard of care for many cardiac arrhythmias like supraventricular tachycardias, atrial fibrillation, premature ventricular complexes (PVC), and monomorphic ventricular tachycardia. In this review, we discuss the recent progress made in the mapping and ablation of ventricular fibrillation (VF). Ventricular activation during VF is apparently disorganized, making mapping and interpretation difficult. Prolonged mapping during VF would require mechanical circulatory support as VF causes complete hemodynamic collapse...
March 6, 2018: Current Treatment Options in Cardiovascular Medicine
Sean M McClure, Patrick L Ahl, Jeffrey T Blue
PURPOSE: The purpose was to evaluate DSF for high throughput screening of protein thermal stability (unfolding/ aggregation) across a wide range of formulations. Particular focus was exploring PROTEOSTAT® - a commercially available fluorescent rotor dye - for detection of aggregation in surfactant containing formulations. Commonly used hydrophobic dyes (e.g. SYPRO™ Orange) interact with surfactants, complicating DSF measurements. METHODS: CRM197 formulations were prepared and analyzed in standard 96-well plate rT-PCR system, using SYPRO™ Orange and PROTEOSTAT® dyes...
March 5, 2018: Pharmaceutical Research
Zhongjie Huang, Leonidas Siozos-Rousoulis, Tim De Troyer, Ghader Ghorbaniasl
This paper presents a time-domain method for noise prediction of supersonic rotating sources in a moving medium. The proposed approach can be interpreted as an extensive time-domain solution for the convected permeable Ffowcs Williams and Hawkings equation, which is capable of avoiding the Doppler singularity. The solution requires special treatment for construction of the emission surface. The derived formula can explicitly and efficiently account for subsonic uniform constant flow effects on radiated noise...
February 2018: Proceedings. Mathematical, Physical, and Engineering Sciences
Laura Martinez-Mateu, Lucia Romero, Ana Ferrer-Albero, Rafael Sebastian, José F Rodríguez Matas, José Jalife, Omer Berenfeld, Javier Saiz
Anatomically based procedures to ablate atrial fibrillation (AF) are often successful in terminating paroxysmal AF. However, the ability to terminate persistent AF remains disappointing. New mechanistic approaches use multiple-electrode basket catheter mapping to localize and target AF drivers in the form of rotors but significant concerns remain about their accuracy. We aimed to evaluate how electrode-endocardium distance, far-field sources and inter-electrode distance affect the accuracy of localizing rotors...
March 5, 2018: PLoS Computational Biology
Martha C Mayorquín-Torres, Abraham Colin-Molina, Salvador Perez-Estrada, Annia Galano, Braulio Rodríguez-Molina, Martin A Iglesias-Arteaga
A novel steroid molecular rotor was obtained in four steps from the naturally occurring spirostane sapogenin diosgenin. The structural and dynamic characterization was carried out by solution NMR, VT X-ray diffraction, solid state 13C CPMAS and solid state 2H NMR experiments. They allowed the identification of a fast dynamic process with a frequency of 14 MHz at room temperature, featuring a barrier to rotation Ea = 7.87 kcal mol-1. The gathered experimental evidence indicated the presence of a hydrogen bond that becomes stronger as the temperature lowers...
March 5, 2018: Journal of Organic Chemistry
Minkyun Noh, Wolfgang Gruber, David L Trumper
We present a new concept of bearingless slice motor that levitates and rotates a ring-shaped solid rotor. The rotor is made of a semi-hard magnetic material exhibiting magnetic hysteresis, such as D2 steel. The rotor is radially biased with a homopolar permanent-magnetic flux, on which the stator can superimpose 2-pole flux to generate suspension forces. By regulating the suspension forces based on position feedback, the two radial rotor degrees of freedom are actively stabilized. The two tilting degrees of freedom and the axial translation are passively stable due to the reluctance forces from the bias flux...
October 2017: IEEE/ASME Transactions on Mechatronics
Armin Fashi, Amir Ahmad Salarian, Abbasali Zamani
A novel and efficient device of solvent stir-bar microextraction (SSBME) system coupled with GC-FID detection was introduced for the pre-concentration and determination of malondialdehyde (MDA) in different biological matrices. In the proposed device, a piece of porous hollow fiber was located on a magnetic rotor by using a stainless steel-wire (as a mechanical support) and the whole device could stir with the magnetic rotor in sample solution cell. The device provided higher pre-concentration factor and better precision in comparison with conventional SBME due to the reproducible, stable and high contact area between the stirred sample and the hollow fiber...
May 15, 2018: Talanta
Christian Scholz, Michael Engel, Thorsten Pöschel
Biological organisms and artificial active particles self-organize into swarms and patterns. Open questions concern the design of emergent phenomena by choosing appropriate forms of activity and particle interactions. A particularly simple and versatile system are 3D-printed robots on a vibrating table that can perform self-propelled and self-spinning motion. Here we study a mixture of minimalistic clockwise and counter-clockwise rotating robots, called rotors. Our experiments show that rotors move collectively and exhibit super-diffusive interfacial motion and phase separate via spinodal decomposition...
March 2, 2018: Nature Communications
Petr Pecina, Hana Nůsková, Vendula Karbanová, Vilma Kaplanová, Tomáš Mráček, Josef Houštěk
The central stalk of mitochondrial ATP synthase consists of subunits γ, δ, and ε, and along with the membraneous subunit c oligomer constitutes the rotor domain of the enzyme. Our previous studies showed that mutation or deficiency of ε subunit markedly decreased the content of ATP synthase, which was otherwise functionaly and structuraly normal. Interestingly, it led to accumulation of subunit c aggregates, suggesting the role of the ε subunit in assembly of individual enzyme domains. In the present study we focused on the role of subunits γ and δ...
February 27, 2018: Biochimica et Biophysica Acta
Takumi Asada, Naoki Yoshihara, Yasushi Ochiai, Shin-Ichiro Kimura, Yasunori Iwao, Shigeru Itai
Water-soluble polymers with high viscosity are frequently used in the design of sustained-release formulations of poorly water-soluble drugs to enable complete release of the drug in the gastrointestinal tract. Tablets containing matrix granules with a water-soluble polymer are preferred because tablets are easier to handle and the multiple drug-release units of the matrix granules decreases the influences of the physiological environment on the drug. However, matrix granules with a particle size of over 800 μm sometimes cause a content uniformity problem in the tableting process because of the large particle size...
February 26, 2018: International Journal of Pharmaceutics
Matthew J Murray, Hannah M Ogden, Amy S Mullin
The collision dynamics of optically centrifuged CO2 with Ar and He are reported here. The optical centrifuge produces an ensemble of CO2 molecules in high rotational states (with J ∼ 220) with oriented angular momentum. Polarization-dependent high-resolution transient IR absorption spectroscopy was used to measure the relaxation dynamics in the presence of Ar or He by probing the CO2 J = 76 and 100 states with Erot =2306 and 3979 cm-1 , respectively. The data show that He relaxes the CO2 super rotors more quickly than Ar...
February 28, 2018: Journal of Chemical Physics
Jinqiao Dong, Xu Li, Kang Zhang, Yi Di Yuan, Yuxiang Wang, Linzhi Zhai, Guoliang Liu, Daqiang Yuan, Jianwen Jiang, Dan Zhao
Despite the rapid development of molecular rotors over the past decade, it still remains a huge challenge to understand their confined behaviour in ultrathin two-dimensional (2D) nanomaterials for molecular recognition. Here we report an all-carbon, 2D π-conjugated aromatic polymer, named NUS-25, containing flexible tetraphenylethylene (TPE) units as aggregation induced emission (AIE) molecular rotors. NUS-25 bulk powder can be easily exfoliated into micrometre-sized lamellar freestanding nanosheets with a thickness of 2 - 5 nm...
February 28, 2018: Journal of the American Chemical Society
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