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https://www.readbyqxmd.com/read/28528218/laboratory-studies-of-ultrasonic-wave-response-of-fractures-with-different-lengths-anisotropy-characteristics-and-coda-analysis
#1
D Wang, S L Qu, Q Zhao, X Y Yin, F Zhou
Ultrasonic wave propagation in a synthetic medium with different scale fractures is investigated through the physics modeling research. The experiment model consisting of two layers, the first layer is divided into four fractured blocks with a constant fracture density but different dimension and a block without fractures as the reference region. The velocity and reflected amplitude of wave derived from the wide azimuth data processing are anisotropic due to the fractured layer. Coda wave characteristics versus offset and azimuth are obviously different for varying fracture scales...
May 13, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28527439/preferential-binding-effects-on-protein-structure-and-dynamics-revealed-by-coarse-grained-monte-carlo-simulation
#2
R B Pandey, D J Jacobs, B L Farmer
The effect of preferential binding of solute molecules within an aqueous solution on the structure and dynamics of the histone H3.1 protein is examined by a coarse-grained Monte Carlo simulation. The knowledge-based residue-residue and hydropathy-index-based residue-solvent interactions are used as input to analyze a number of local and global physical quantities as a function of the residue-solvent interaction strength (f). Results from simulations that treat the aqueous solution as a homogeneous effective solvent medium are compared to when positional fluctuations of the solute molecules are explicitly considered...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28527369/prolonged-epileptiform-eeg-runs-are-associated-with-persistent-seizures-in-juvenile-myoclonic-epilepsy
#3
Vibeke Arntsen, Trond Sand, Marte R Syvertsen, Eylert Brodtkorb
OBJECTIVE: In juvenile myoclonic epilepsy (JME), various EEG characteristics have been suggested as poor prognostic signs, but their significance is unclear. The aim of this study was to assess the influence of EEG variables on seizure and psychosocial outcome after a follow-up exceeding 20 years. METHODS: 396 EEG recordings were available for assessment in 40 patients (42 complete digital, 330 paper segments and 24 written reports only). Mean follow-up was 31 years (range 20-68)...
May 8, 2017: Epilepsy Research
https://www.readbyqxmd.com/read/28526702/t-wave-morphology-restitution-predicts-sudden-cardiac-death-in-patients-with-chronic-heart-failure
#4
Julia Ramírez, Michele Orini, Ana Mincholé, Violeta Monasterio, Iwona Cygankiewicz, Antonio Bayés de Luna, Juan Pablo Martínez, Esther Pueyo, Pablo Laguna
BACKGROUND: Patients with chronic heart failure are at high risk of sudden cardiac death (SCD). Increased dispersion of repolarization restitution has been associated with SCD, and we hypothesize that this should be reflected in the morphology of the T-wave and its variations with heart rate. The aim of this study is to propose an electrocardiogram (ECG)-based index characterizing T-wave morphology restitution (TMR), and to assess its association with SCD risk in a population of chronic heart failure patients...
May 19, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28524674/holography-of-wi-fi-radiation
#5
Philipp M Holl, Friedemann Reinhard
Wireless data transmission systems such as wi-fi or Bluetooth emit coherent light-electromagnetic waves with a precisely known amplitude and phase. Propagating in space, this radiation forms a hologram-a two-dimensional wave front encoding a three-dimensional view of all objects traversed by the light beam. Here we demonstrate a scheme to record this hologram in a phase-coherent fashion across a meter-sized imaging region. We recover three-dimensional views of objects and emitters by feeding the resulting data into digital reconstruction algorithms...
May 5, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28522734/voluntary-control-of-epileptiform-spike-wave-discharges-in-awake-rats
#6
Jeremy A Taylor, Krista M Rodgers, Florencia M Bercum, Carmen J Booth, F Edward Dudek, Daniel S Barth
Genetically inherited absence epilepsy in humans is typically characterized by brief (seconds) spontaneous seizures, which involve spike-wave discharges (SWDs) in the EEG and interruption of consciousness and ongoing behavior. Genetic (inbred) models of this disorder in rats have been used to examine mechanisms, comorbidities and anti-absence drugs. SWDs have also been proposed as models of complex partial seizures (CPSs) following traumatic brain injury (post-traumatic epilepsy; PTE). However, the ictal characteristics of these rat models, including SWDs and associated immobility, are also prevalent in healthy outbred laboratory rats...
May 17, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28522275/impact-of-continuous-positive-airway-pressure-on-left-ventricular-systolic-loading-and-coronary-flow-reserve-in-healthy-young-men
#7
Volker Schulze, Christian Meyer, Christian Eickholt, Roberto Sansone, Stefanie Keymel, Christian Heiss, Tienush Rassaf, Malte Kelm, Stephan Steiner
BACKGROUND: Increased augmentation index (AIx) is accompanied by an elevated cardiovascular risk. A reduction of AIx is known for long-term continuous positive airway pressure (CPAP) therapy. We hypothesised that acute preload and left ventricular workload effects AIx and subendocardial viability ratio (SEVR) as a marker of coronary flow reserve. METHODS: Increased augmentation index and central blood pressure parameters were measured by radial artery tonometry in 17 healthy men (32/±6years) at rest and during CPAP ventilation at pressures of 5, 10mbar and after recovery...
March 31, 2017: Heart, Lung & Circulation
https://www.readbyqxmd.com/read/28521497/thermal-decomposition-of-nitromethane-and-reaction-between-ch3-and-no2
#8
Akira Matsugi, Hiroumi Shiina
The thermal decomposition of gaseous nitromethane and the subsequent bimolecular reaction between CH3 and NO2 have been experimentally studied using time-resolved cavity-enhanced absorption spectroscopy behind reflected shock waves in the temperature range 1336-1827 K and at pressure of 100 kPa. Temporal evolution of NO2 was observed following the pyrolysis of nitromethane (diluted to 80-140 ppm in argon) by monitoring the absorption around 400 nm. The primary objectives of the current work were to evaluate the rate constant for the CH3 + NO2 reaction (k2) and to examine the contribution of the roaming isomerization pathway in nitromethane decomposition...
May 19, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28521204/numerical-simulations-of-mechanical-and-ignition-deflagration-responses-for-pbxs-under-low-to-medium-level-velocity-impact-loading
#9
Kun Yang, Yanqing Wu, Fenglei Huang, Ming Li
An effective computational model is required to accurately predict the dynamic responses in accidental initiations of explosives. The present work uses a series of two-dimensional mechanical-chemical simulations performed via a hydrodynamic-code, DREXH-2D, to efficiently describe the mechanical and ignition-deflagration responses of cased cylindrical polymer-bonded explosives (PBXs) undergoing a low-to-medium-level impact (70-350m/s) in longitudinal direction. The ignition response was predicted based on an ignition criterion of effective plastic work...
May 8, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28518192/time-resolved-signatures-across-the-intramolecular-response-in-substituted-cyanine-dyes
#10
Muath Nairat, Morgan Webb, Michael P Esch, Vadim V Lozovoy, Benjamin G Levine, Marcos Dantus
The optically populated excited state wave packet propagates along multidimensional intramolecular coordinates soon after photoexcitation. This action occurs alongside an intermolecular response from the surrounding solvent. Disentangling the multidimensional convoluted signal enables the possibility to separate and understand the initial intramolecular relaxation pathways over the excited state potential energy surface. Here we track the initial excited state dynamics by measuring the fluorescence yield from the first excited state as a function of time delay between two color femtosecond pulses for several cyanine dyes having different substituents...
May 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28516283/developmental-window-of-sensorineural-deafness-in-biotinidase-deficient-mice
#11
Kathleen June Maheras, Kirit Pindolia, Barry Wolf, Alexander Gow
Biotinidase deficiency is an autosomal recessively inherited disorder that results in the inability to recycle the vitamin, biotin. If untreated, the disorder can result in a range of neurological and cutaneous symptoms, including sensorineural deficits and deafness. To understand early mechanistic abnormalities that may precede more generalized and nonspecific effects of metabolic deficits such as weight loss and acidosis, we have analyzed auditory brainstem responses (ABRs) in biotinidase-deficient knockout (Btd (-/-) ) mice in the periweaning period with or without dietary biotin supplementation...
May 17, 2017: Journal of Inherited Metabolic Disease
https://www.readbyqxmd.com/read/28515820/arterial-velocity-pulse-index-as-a-novel-marker-of-atherosclerosis-using-pulse-wave-analysis-on-high-sensitivity-troponin-t-in-hypertensive-patients
#12
Takashi Hitsumoto
BACKGROUND: The arterial velocity pulse index (AVI) is explored as a novel marker of atherosclerosis using pulse wave analysis in clinical settings. Recent clinical studies have reported that the level of high-sensitivity troponin T (hs-cTnT) is an important biomarker in hypertensive patients. The aim of this study was to clarify the impact of AVI on hs-cTnT in these patients. METHODS: This study enrolled 455 hypertensive outpatients (181 males and 274 females; mean age, 65 ± 11 years (mean ± standard deviation)) without a history of cardiovascular events...
April 2017: Cardiology Research
https://www.readbyqxmd.com/read/28515119/pulse-wave-velocity-predicts-response-to-renal-denervation-in-isolated-systolic-hypertension
#13
Karl Fengler, Karl-Philipp Rommel, Robert Hoellriegel, Stephan Blazek, Christian Besler, Steffen Desch, Gerhard Schuler, Axel Linke, Philipp Lurz
BACKGROUND: Renal sympathetic denervation seems to be less effective as a treatment for hypertension in patients with isolated systolic hypertension, a condition associated with elevated central arterial stiffness. Because isolated systolic hypertension can also be caused by wave reflection or increased cardiac output, a more differentiated approach might improve patient preselection for renal sympathetic denervation. We sought to evaluate the additional predictive value of invasive pulse wave velocity for response to renal sympathetic denervation in patients with combined versus isolated systolic hypertension...
May 17, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28506233/measurement-and-decomposition-of-socioeconomic-inequality-in-single-and-multimorbidity-in-older-adults-in-china-and-ghana-results-from-the-who-study-on-global-ageing-and-adult-health-sage
#14
Rasha Kunna, Miguel San Sebastian, Jennifer Stewart Williams
BACKGROUND: Globally people are living longer and enduring non-communicable diseases (NCDs) many of which co-occur as multimorbidity. Demographic and socioeconomic factors are determinants of inequalities and inequities in health. There is a need for country-specific evidence of NCD inequalities in developing countries where populations are ageing rapidly amid economic and social change. The study measures and decomposes socioeconomic inequality in single and multiple NCD morbidity in adults aged 50 and over in China and Ghana...
May 15, 2017: International Journal for Equity in Health
https://www.readbyqxmd.com/read/28504758/pulse-picker-for-synchrotron-radiation-driven-by-a-surface-acoustic-wave
#15
Simone Vadilonga, Ivo Zizak, Dmitry Roshchupkin, Andrei Petsiuk, Igor Dolbnya, Kawal Sawhney, Alexei Erko
A functional test for a pulse picker for synchrotron radiation was performed at Diamond Light Source. The purpose of a pulse picker is to select which pulse from the synchrotron hybrid-mode bunch pattern reaches the experiment. In the present work, the Bragg reflection on a Si/B<sub>4</sub>C multilayer was modified using surface acoustic wave (SAW) trains. Diffraction on the SAW alters the direction of the x rays and it can be used to modulate the intensity of the x rays that reach the experimental chamber...
May 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28500898/the-fact-not-to-ignore-mean-blood-pressure-is-the-main-predictor-of-increased-arterial-stiffness-in-patients-with-systemic-rheumatic-diseases
#16
Alma Čypienė, Jolanta Dadonienė, Dalia Miltinienė, Egidija Rinkūnienė, Rita Rugienė, Sigita Stropuvienė, Jolita Badarienė, Aleksandras Laucevičius
PURPOSE: We aimed to evaluate the association between carotid-radial pulse wave velocity (PWV), augmentation index (AIx), and flow-mediated dilatation (FMD) of the brachial artery and factors potentially influencing them in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). MATERIAL AND METHODS: 316 patients diagnosed with RA (32%), SLE (20%), SSc (16%) and 156 controls (32%) were included in the study. Parameters of arterial stiffness AIx and PWV were obtained using applanation tonometry...
May 10, 2017: Advances in Medical Sciences
https://www.readbyqxmd.com/read/28500308/ultrafast-all-optical-tuning-of-direct-gap-semiconductor-metasurfaces
#17
Maxim R Shcherbakov, Sheng Liu, Varvara V Zubyuk, Aleksandr Vaskin, Polina P Vabishchevich, Gordon Keeler, Thomas Pertsch, Tatyana V Dolgova, Isabelle Staude, Igal Brener, Andrey A Fedyanin
Optical metasurfaces are regular quasi-planar nanopatterns that can apply diverse spatial and spectral transformations to light waves. However, metasurfaces are no longer adjustable after fabrication, and a critical challenge is to realise a technique of tuning their optical properties that is both fast and efficient. We experimentally realise an ultrafast tunable metasurface consisting of subwavelength gallium arsenide nanoparticles supporting Mie-type resonances in the near infrared. Using transient reflectance spectroscopy, we demonstrate a picosecond-scale absolute reflectance modulation of up to 0...
May 12, 2017: Nature Communications
https://www.readbyqxmd.com/read/28498698/topological-phases-of-parafermions-a-model-with-exactly-solvable-ground-states
#18
Fernando Iemini, Christophe Mora, Leonardo Mazza
Parafermions are emergent excitations that generalize Majorana fermions and can also realize topological order. In this Letter, we present a nontrivial and quasi-exactly-solvable model for a chain of parafermions in a topological phase. We compute and characterize the ground-state wave functions, which are matrix-product states and have a particularly elegant interpretation in terms of Fock parafermions, reflecting the factorized nature of the ground states. Using these wave functions, we demonstrate analytically several signatures of topological order...
April 28, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28498685/pt-symmetric-scattering-in-flow-duct-acoustics
#19
Yves Aurégan, Vincent Pagneux
We show theoretically and experimentally that the propagation of an acoustic wave in an airflow duct going through a pair of diaphragms, with equivalent amounts of mean-flow-induced effective gain and loss, displays all the features of a parity-time (PT) symmetric system. Using a scattering matrix formalism, we observe, experimentally, the properties which reflect the PT symmetry of the scattering acoustical system: the existence of spontaneous symmetry breaking with symmetry-broken pairs of scattering eigenstates showing amplification and reduction, and the existence of points with unidirectional invisibility...
April 28, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28497790/quantum-vertex-model-for-reversible-classical-computing
#20
C Chamon, E R Mucciolo, A E Ruckenstein, Z-C Yang
Mappings of classical computation onto statistical mechanics models have led to remarkable successes in addressing some complex computational problems. However, such mappings display thermodynamic phase transitions that may prevent reaching solution even for easy problems known to be solvable in polynomial time. Here we map universal reversible classical computations onto a planar vertex model that exhibits no bulk classical thermodynamic phase transition, independent of the computational circuit. Within our approach the solution of the computation is encoded in the ground state of the vertex model and its complexity is reflected in the dynamics of the relaxation of the system to its ground state...
May 12, 2017: Nature Communications
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