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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
Nicholas B Miner, James P O'Callaghan, Tamara J Phillips, Aaron Janowsky
The rise in popularity of substituted methcathinones (aka "bath salts") has increased the focus on their neurotoxic effects. Two commonly abused methcathinones, 3,4-methylenedioxymethcathinone (methylone, MDMC) and 3,4-methylenedioxypyrovalerone (MDPV), are often concomitantly ingested with the illicit drug 3,4-methylenedioxymethamphetamine (MDMA). To examine potential neurotoxic effects of these drug combinations, C57BL/6J mice were administered 4 i.p. injection of the drugs, at 2h intervals, either singularly: MDMA 15 or 30mg/kg, methylone 20mg/kg, MDPV 1mg/kg; or in combination: methylone/MDMA 20/15mg/kg, MDPV/MDMA 1/15mg/kg...
February 14, 2017: Neurotoxicology and Teratology
Luis Miguel Gutiérrez Robledo
No abstract text is available yet for this article.
February 13, 2017: Revista Española de Geriatría y Gerontología
Zhen Chen, Xianbin Liu
Noise-induced escape from the domain of attraction of a nonhyperbolic chaotic attractor in a periodically excited nonlinear oscillator is further investigated. Deviations are found to be amplified at the primary homoclinic tangency from which the optimal force begins to fluctuate dramatically. Escaping trajectories turn out to possess several modes to pass through the saddle cycle on the basin boundary, and each mode corresponds to a certain type of value of the action plot, respectively. A subset of the pattern of fluctuational paths from the chaotic attractor is obtained, showing the existence of complicated singularities...
January 2017: Physical Review. E
Péter Lajkó, Ferenc Iglói
The entanglement entropy S is an indicator of quantum correlations in the ground state of a many-body quantum system. At a second-order quantum phase-transition point in one dimension S generally has a logarithmic singularity. Here we consider quantum spin chains with a first-order quantum phase transition, the prototype being the Q-state quantum Potts chain for Q>4 and calculate S across the transition point. According to numerical, density matrix renormalization group results at the first-order quantum phase transition point S shows a jump, which is expected to vanish for Q→4^{+}...
January 2017: Physical Review. E
Yuri Maistrenko, Serhiy Brezetsky, Patrycja Jaros, Roman Levchenko, Tomasz Kapitaniak
We demonstrate that chimera behavior can be observed in small networks consisting of three identical oscillators, with mutual all-to-all coupling. Three different types of chimeras, characterized by the coexistence of two coherent oscillators and one incoherent oscillator (i.e., rotating with another frequency) have been identified, where the oscillators show periodic (two types) and chaotic (one type) behaviors. Typical bifurcations at the transitions from full synchronization to chimera states and between different types of chimeras have been described...
January 2017: Physical Review. E
Rafael S Oliveira, Roberto F S Andrade
This work investigates the influence of geometrical features of the Apollonian packing (AP) on the behavior of magnetic models. The proposed model differs from previous investigations on the Apollonian network (AN), where the magnetic coupling constants depend only on the properties of the network structure defined by the packing, but not on quantitative aspects of its geometry. In opposition to the exact scale invariance observed in the AN, the circle's sizes in the AP are scaled by different factors when one goes from one generation to the next, requiring a different approach for the evaluation of the model's properties...
January 2017: Physical Review. E
Krishna K Verma
Relative to many other areas in chemistry, analytical chemistry appears singularly lagging behind in India despite the commendable growth it had shown in the past both in teaching and research. Certain presumptions in policy making and current educational practices are believed to be the crux of the problem.
February 7, 2017: Analytical Chemistry
Jesus Garoz-Ruiz, Aranzazu Heras, Alvaro Colina
The study of real samples is more complicated than the study of other systems. However, the inherent advantages of UV-vis absorption spectroelectrochemistry should overcome some difficulties related to direct measurements in complex matrices. For this reason, a singular spectroelectrochemistry device has been fabricated and validated. The novel cell is based on single-walled carbon nanotubes, which are filtered and subsequently press-transferred on a polyethylene terephthalate support using a stencil with a custom design...
February 7, 2017: Analytical Chemistry
Ashok Mondal, Ishan Saxena, Hong Tang, Poulami Banerjee
The main difficulty encountered in interpretation of cardiac sound is interference of noise. The contaminated noise obscures the relevant information which are useful for recognition of heart diseases. The unwanted signals are produced mainly by lungs and surrounding environment. In this paper, a novel heart sound de-noising technique has been introduced based on a combined framework of wavelet packet transform (WPT) and singular value decomposition (SVD). The most informative node of wavelet tree is selected on the criteria of mutual information measurement...
February 13, 2017: IEEE Journal of Biomedical and Health Informatics
Luis Moreira, Beatriz M Illescas, Nazario Martín
Since its discovery, crown ethers as well as the most recent carbon nanostructures, namely fullerenes, carbon nanotubes and graphene, have received a lot of attention from the chemical community. As a proof, these innovative chemical structures have gathered three Nobel Prizes in 1987, 1996 and 2010 corresponding to crown ethers, fullerenes and graphene, respectively. Merging these singular chemical structures has provided a wealth number of unprecedented supramolecular assemblies with new geometrical and electronic properties whose more representative examples have been presented in this synopsis organized according to the different nature of the carbon nanostructures...
February 16, 2017: Journal of Organic Chemistry
Uwe Manthe, Thomas Weike
A multi-layer multi-configurational time-dependent Hartree (MCTDH) approach using a second quantization representation (SQR) based on optimized time-dependent orbitals is introduced. The approach combines elements of the multi-layer MCTDH-SQR approach of Wang and Thoss, which employs a preselected time-independent orbital basis, and the MCTDH for bosons and multi-configuration time-dependent Hartree-Fock approaches, which do not use multi-layering but employ time-dependent orbital bases. In contrast to existing MCTDH-type approaches, the results of the present approach for a given number of configurations are not invariant with respect to unitary transformations of the time-dependent orbital basis...
February 14, 2017: Journal of Chemical Physics
Yukio Kawashima, Kimihiko Hirao
We introduced two methods to correct the singularity in the calculation of long-range HF exchange for long-range corrected density functional theory (LC-DFT) calculations in plane-wave basis sets. The first method introduces an auxiliary function to cancel out the singularity. The second method introduces a truncated long-range Coulomb potential, which has no singularity. We assessed the introduced methods using the LC-BLYP functional by applying it to isolated systems of naphthalene and pyridine. We first compared the total energies and the HOMO energies of the singularity-corrected and uncorrected calculations and confirmed that singularity correction is essential for LC-DFT calculations using plane-wave basis sets...
February 15, 2017: Journal of Physical Chemistry. A
C N Alexeyev, A O Kovalyova, A F Rubass, A V Volyar, M A Yavorsky
We demonstrate that in circular arrays of anisotropic fibers at certain distribution of anisotropy directors robust transmission of optical fields with half-integer topological charges is possible. We show that this is possible because the supermodes of such arrays may contain in their circularly polarized components half-integer topological charges of opposite values. We also study the structure of singularities in these supermodes.
February 15, 2017: Optics Letters
Lisa Messeri
Science and technology studies (STS) and critical cartography are both asking questions about the ontological fixity of maps and other scientific objects. This paper examines how a group of NASA computer scientists who call themselves The Mapmakers conceptualizes and creates maps in service of different commitments. The maps under construction are those of alien Mars, produced through partnerships that NASA has established with Google and Microsoft. With the goal of bringing an experience of Mars to as many people as possible, these maps influence how we imagine our neighbouring planet...
February 2017: Social Studies of Science
Valery S Shchesnovich
For N indistinguishable bosons or fermions impinged on a M-port Haar-random unitary network the average probability to count n 1, … n r particles in a small number r ≪ N of binned-together output ports takes a Gaussian form as N ≫ 1. The discovered Gaussian asymptotic law is the well-known asymptotic law for distinguishable particles, governed by a multinomial distribution, modified by the quantum statistics with stronger effect for greater particle density N/M. Furthermore, it is shown that the same Gaussian law is the asymptotic form of the probability to count particles at the output bins of a fixed multiport with the averaging performed over all possible configurations of the particles in the input ports...
December 2017: Scientific Reports
Takanori Uchiyama, Taiki Tomoshige
A mechanomyogram (MMG) measured with a displacement sensor (displacement MMG) can provide a better estimation of longitudinal muscle stiffness than that measured with an acceleration sensor (acceleration MMG), but the displacement MMG cannot provide transverse muscle stiffness. We propose a method to estimate both longitudinal and transverse muscle stiffness from a velocity MMG using a system identification technique. The aims of this study are to show the advantages of the proposed method. The velocity MMG was measured using a capacitor microphone and a differential circuit, and the MMG, evoked by electrical stimulation, of the tibialis anterior muscle was measured five times in seven healthy young male volunteers...
February 1, 2017: Journal of Electromyography and Kinesiology
Guangqing Wang, Jiang Zhou
Let H be Monge-Ampère singular integral operator, [Formula: see text], and [Formula: see text]. It is proved that the commutator [Formula: see text] is bounded from [Formula: see text] to [Formula: see text] for [Formula: see text] and from [Formula: see text] to [Formula: see text] for [Formula: see text]. For the extreme case [Formula: see text], a weak estimate is given.
2017: J Inequal Appl
Daniela Barbosa da Silva Lins, Fernando Ravanini Gardon, João Frederico da Costa Azevedo Meyer, Rozely Ferreira Dos Santos
The selection of forest fragments for conservation is usually based on spatial parameters as forest size and canopy integrity. This strategy assumes that chosen fragments present high conservation status, ensuring biodiversity and ecological functions. We argue that a well-preserved forest fragment that remains connected by the landscape structure, does not necessarily hold attributes that ensure the presence of keystone species. We also discuss that the presence of keystone species does not always mean that it has the best conditions for its occurrence and maintenance...
February 10, 2017: Environmental Management
Jeng-Tze Huang, Thanh-Phong Pham
Issues of differentiation-free multiswitching neuroadaptive tracking control of strict-feedback systems are presented. It mainly consists of a set of nominal adaptive neural network compensators plus an auxiliary switched linear controller that ensures the semiglobally/globally ultimately uniformly bounded stability when the unknown nonlinearities are locally/globally linearly bounded, respectively. In particular, the so-called explosion of complexity is annihilated in two steps. First, a set of first-order low-pass filters are constructed for solving such a problem in the nominal neural compensators...
February 7, 2017: IEEE Transactions on Neural Networks and Learning Systems
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