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https://www.readbyqxmd.com/read/28444501/validation-of-numerical-simulation-methods-in-aortic-arch-using-4d-flow-mri
#1
Shohei Miyazaki, Keiichi Itatani, Toyoki Furusawa, Teruyasu Nishino, Masataka Sugiyama, Yasuo Takehara, Satoshi Yasukochi
Computational fluid dynamics (CFD) are the gold standard in studying blood flow dynamics. However, CFD results are dependent on the boundary conditions and the computation model. The purpose of this study was to validate CFD methods using comparison with actual measurements of the blood flow vector obtained with four-dimensional (4D) flow magnetic resonance imaging (MRI). 4D Flow MRI was performed on a healthy adult and a child with double-aortic arch. The aortic lumen was segmented to visualize the blood flow...
April 25, 2017: Heart and Vessels
https://www.readbyqxmd.com/read/28442789/elastic-turbulence-in-entangled-semi-dilute-dna-solutions-measured-with-optical-coherence-tomography-velocimetry
#2
A V Malm, T A Waigh
The flow instabilities of solutions of high molecular weight DNA in the entangled semi-dilute concentration regime were investigated using optical coherence tomography velocimetry, a technique that provides high spatial (probe volumes of 3.4 pL) and temporal resolution (sub μs) information on the flow behaviour of complex fluids in a rheometer. The velocity profiles of the opaque DNA solutions (high and low salt) were measured as a function of the distance across the gap of a parallel plate rheometer, and their evolution over time was measured...
April 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28442705/model-of-electrical-activity-in-cardiac-tissue-under-electromagnetic-induction
#3
Fuqiang Wu, Chunni Wang, Ying Xu, Jun Ma
Complex electrical activities in cardiac tissue can set up time-varying electromagnetic field. Magnetic flux is introduced into the Fitzhugh-Nagumo model to describe the effect of electromagnetic induction, and then memristor is used to realize the feedback of magnetic flux on the membrane potential in cardiac tissue. It is found that a spiral wave can be triggered and developed by setting specific initials in the media, that is to say, the media still support the survival of standing spiral waves under electromagnetic induction...
December 23, 2016: Scientific Reports
https://www.readbyqxmd.com/read/28442137/enhanced-surface-ozone-during-the-heat-wave-of-2013-in-yangtze-river-delta-region-china
#4
X Pu, T J Wang, X Huang, D Melas, P Zanis, D K Papanastasiou, A Poupkou
Under the background of global warming, occurrence of heat waves has increased in most part of Europe, Asia and Australia along with enhanced ozone level. In this paper, observational air temperature and surface ozone in the Yangtze River Delta (YRD) region of China during summer of 2013, and the regional chemistry-climate model (RegCM-CHEM4) were applied to explore the relationship between heat wave and elevated ground-level ozone. Observations indicated that YRD experienced severe heat waves with maximum temperature up to 41...
April 22, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28440643/field-calibration-of-xad-based-passive-air-sampler-on-the-tibetan-plateau-wind-influence-and-configuration-improvement
#5
Ping Gong, Xiao-Ping Wang, Xiande Liu, Frank Wania
The passive air sampler based on XAD-2 resin (XAD-PAS) has proven useful for collecting atmospheric persistent organic pollutants (POPs) in remote regions. Whereas laboratory studies have shown that, due to the open bottom of its housing, the passive sampling rate (PSR) of the XAD-PAS is susceptible to wind and other processes causing air turbulence, the sampler has not been calibrated in the field at sites experiencing high winds. In this study, the PSRs of the XAD-PAS were calibrated at three sites on the Tibetan Plateau, covering a wide range in temperature (T), pressure (P) and wind speed (v)...
April 25, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28435862/financialization-impedes-climate-change-mitigation-evidence-from-the-early-american-solar-industry
#6
Max Jerneck
The article investigates how financialization impedes climate change mitigation by examining its effects on the early history of one low-carbon industry, solar photovoltaics in the United States. The industry grew rapidly in the 1970s, as large financial conglomerates acquired independent firms. While providing needed financial support, conglomerates changed the focus from existing markets in consumer applications toward a future utility market that never materialized. Concentration of the industry also left it vulnerable to the corporate restructuring of the 1980s, when the conglomerates were dismantled and solar divisions were pared back or sold off to foreign firms...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28434823/influence-of-serum-and-polystyrene-plate-type-on-stability-of-candida-albicans-biofilms
#7
Purity N Kipanga, Walter Luyten
Adhesion is a crucial initial step in microbial biofilm formation. Firm attachment to a target surface subsequently ensures successful colonization and survival despite turbulent conditions. In the laboratory, polystyrene plates are commonly used in biofilm experiments and the 'washing/rinse steps' before staining are critical for assaying biofilm viability. However, these rinse steps risk the removal (partially or entirely) of the formed biofilm, resulting in inconsistent results. The aim of the present study was to optimize conditions for firmer biofilms, less prone to disruption and thus significantly reducing well-to-well variability...
April 20, 2017: Journal of Microbiological Methods
https://www.readbyqxmd.com/read/28434714/speed-resolution-advantage-of-turbulent-supercritical-fluid-chromatography-in-open-tubular-columns-ii-theoretical-and-experimental-evidences
#8
Fabrice Gritti, Michael Fogwill
The potential advantage of turbulent supercritical fluid chromatography (TSFC) in open tubular columns (OTC) was evaluated on both theoretical and practical viewpoints. First, the dispersion model derived by Golay in 1958 and recently extended from laminar to turbulent flow regime is used for the predictions of the speed-resolution performance in TSFC. The average dispersion coefficient of matter in the turbulent flow regime was taken from the available experimental data over a range of Reynolds number from 2000 to 6000...
April 19, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28432482/the-sensible-health-care-professional-a-care-ethical-perspective-on-the-role-of-caregivers-in-emotionally-turbulent-practices
#9
Vivianne Baur, Inge van Nistelrooij, Linus Vanlaere
This article discusses the challenging context that health care professionals are confronted with, and the impact of this context on their emotional experiences. Care ethics considers emotions as a valuable source of knowledge for good care. Thinking with care ethical theory and looking through a care ethical lens at a practical case example, the authors discern reflective questions that (1) shed light on a care ethical approach toward the role of emotions in care practices, and (2) may be used by practitioners and facilitators for care ethical reflection on similar cases, in the particular and concrete context where issues around emotional experiences arise...
April 21, 2017: Medicine, Health Care, and Philosophy
https://www.readbyqxmd.com/read/28430497/observation-of-thermal-equilibrium-in-capillary-wave-turbulence
#10
Guillaume Michel, François Pétrélis, Stéphan Fauve
We investigate capillary wave turbulence at scales larger than the forcing one. At such scales, our measurements show that the surface waves dynamics is the one of a thermal equilibrium state in which the effective temperature is related to the injected power. We characterize this evolution with a scaling law and report the statistical properties of the large-scale surface elevation depending on this effective temperature.
April 7, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28430305/turbulence-measurements-in-an-axial-rotary-blood-pump-with-laser-doppler-velocimetry
#11
Chan Y Schüle, Klaus Affeld, Max Kossatz, Christian O Paschereit, Ulrich Kertzscher
BACKGROUND: The implantation of rotary blood pumps as ventricular assist devices (VADs) has become a viable therapy for quite a number of patients with end-stage heart failure. However, these rotary blood pumps cause adverse events that are related to blood trauma. It is currently believed that turbulence in the pump flow plays a significant role. But turbulence has not been measured to date because there is no optical access to the flow space in rotary blood pumps because of their opaque casings...
April 18, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28430266/machine-learning-approach-to-oam-beam-demultiplexing-via-convolutional-neural-networks
#12
Timothy Doster, Abbie T Watnik
Orbital angular momentum (OAM) beams allow for increased channel capacity in free-space optical communication. Conventionally, these OAM beams are multiplexed together at a transmitter and then propagated through the atmosphere to a receiver where, due to their orthogonality properties, they are demultiplexed. We propose a technique to demultiplex these OAM-carrying beams by capturing an image of the unique multiplexing intensity pattern and training a convolutional neural network (CNN) as a classifier. This CNN-based demultiplexing method allows for simplicity of operation as alignment is unnecessary, orthogonality constraints are loosened, and costly optical hardware is not required...
April 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28430237/experimental-study-of-propagation-properties-of-vortex-beams-in-oceanic-turbulence
#13
Zhenglin Liu, Jialin Chen, Daomu Zhao
The intensity of vortex beams always changes on propagation through oceanic turbulence, which is influenced by parameters of turbulence. This property is usually researched only by numerical simulation. Recently, a new method with a spatial light modulator (SLM) can be used in a laboratory to show various turbulence, which makes it possible to construct a system of a beam passing through turbulence by experiment. We investigate a vortex beam propagating through oceanic turbulence with a spiral phase plate and SLM in the laboratory and obtain the intensity distribution images by a charge-coupled device...
April 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28430120/autonomous-multi-robot-search-for-a-hazardous-source-in-a-turbulent-environment
#14
Branko Ristic, Daniel Angley, Bill Moran, Jennifer L Palmer
Finding the source of an accidental or deliberate release of a toxic substance into the atmosphere is of great importance for national security. The paper presents a search algorithm for turbulent environments which falls into the class of cognitive (infotaxi) algorithms. Bayesian estimation of the source parameter vector is carried out using the Rao-Blackwell dimension-reduction method, while the robots are controlled autonomously to move in a scalable formation. Estimation and control are carried out in a centralised replicated fusion architecture assuming all-to-all communication...
April 21, 2017: Sensors
https://www.readbyqxmd.com/read/28425926/chemical-source-localization-fusing-concentration-information-in-the-presence-of-chemical-background-noise
#15
Víctor Pomareda, Rudys Magrans, Juan M Jiménez-Soto, Dani Martínez, Marcel Tresánchez, Javier Burgués, Jordi Palacín, Santiago Marco
We present the estimation of a likelihood map for the location of the source of a chemical plume dispersed under atmospheric turbulence under uniform wind conditions. The main contribution of this work is to extend previous proposals based on Bayesian inference with binary detections to the use of concentration information while at the same time being robust against the presence of background chemical noise. For that, the algorithm builds a background model with robust statistics measurements to assess the posterior probability that a given chemical concentration reading comes from the background or from a source emitting at a distance with a specific release rate...
April 20, 2017: Sensors
https://www.readbyqxmd.com/read/28425452/estimating-the-irreversible-pressure-drop-across-a-stenosis-by-quantifying-turbulence-production-using-4d-flow-mri
#16
Hojin Ha, Jonas Lantz, Magnus Ziegler, Belen Casas, Matts Karlsson, Petter Dyverfeldt, Tino Ebbers
The pressure drop across a stenotic vessel is an important parameter in medicine, providing a commonly used and intuitive metric for evaluating the severity of the stenosis. However, non-invasive estimation of the pressure drop under pathological conditions has remained difficult. This study demonstrates a novel method to quantify the irreversible pressure drop across a stenosis using 4D Flow MRI by calculating the total turbulence production of the flow. Simulation MRI acquisitions showed that the energy lost to turbulence production can be accurately quantified with 4D Flow MRI within a range of practical spatial resolutions (1-3 mm; regression slope = 0...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28422657/phased-array-ultrasound-system-for-planar-flow-mapping-in-liquid-metals
#17
Kevin Mader, Richard Nauber, Vladimir Galindo, Hannes Beyer, Lars Buttner, Sven Eckert, Jurgen Czarske
Controllable magnetic fields can be used to optimize flows in technical and industrial processes involving liquid metals in order to improve quality and yield. However, experimental studies in magnetohydrodynamics (MHD) often involve complex, turbulent flows and require planar, two-component velocity measurements through only one acoustical access. We present the phased array ultrasound Doppler velocimeter (PAUDV) as a modular research platform for flow mapping in liquid metals. It combines the pulse wave Doppler method with the phased array technique to adaptively focus the ultrasound beam...
April 12, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28422636/impact-of-pans-and-pandas-exacerbations-on-occupational-performance-a-mixed-methods-study
#18
Janice Trigilio Tona, Sutanuka Bhattacharjya, Denise Calaprice
OBJECTIVE: Pediatric acute-onset neuropsychiatric syndrome (PANS) includes pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections and involves sudden-onset neuropsychiatric symptoms, including obsessions, compulsions, sensory difficulties, and dysgraphia after infection or other triggers. Our objective was to identify problems with areas of occupation, body functions, and performance skills during exacerbations. METHOD: In this online retrospective study, based on the Occupational Therapy Practice Framework: Domain and Process (2nd ed...
May 2017: American Journal of Occupational Therapy: Official Publication of the American Occupational Therapy Association
https://www.readbyqxmd.com/read/28418648/a-modular-flow-through-platform-for-spectroelectrochemical-analysis
#19
Tomer Noyhouzer, Michael Edward Snowden, Ushula M Tefashe, Janine Mauzeroll
A new type of flow platform for electrochemical and spectroelectrochemical measurements is presented. Finite element method simulations confirm that the hydrodynamic profile within the device is not turbulent, and provides an analytical platform for the investigation of homogenous kinetics, radical lifetimes and reaction mechanisms. The modular "plug and play" configuration of the platform allows one to carry out electrochemistry and spectroscopy individually or simultaneously. Specific demonstrations of electroanalytical measurements using the flow system platform includes voltammetric analysis of organometallic compounds and quantitative analysis of ascorbic acid in commercial orange juice samples...
April 18, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28415375/nonlinear-monte-carlo-model-of-superdiffusive-shock-acceleration-with-magnetic-field-amplification
#20
Andrei M Bykov, Donald C Ellison, Sergei M Osipov
Fast collisionless shocks in cosmic plasmas convert their kinetic energy flow into the hot downstream thermal plasma with a substantial fraction of energy going into a broad spectrum of superthermal charged particles and magnetic fluctuations. The superthermal particles can penetrate into the shock upstream region producing an extended shock precursor. The cold upstream plasma flow is decelerated by the force provided by the superthermal particle pressure gradient. In high Mach number collisionless shocks, efficient particle acceleration is likely coupled with turbulent magnetic field amplification (MFA) generated by the anisotropic distribution of accelerated particles...
March 2017: Physical Review. E
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