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Heat wave

Yufeng Deng, Ned C Rouze, Mark L Palmeri, Kathryn R Nightingale
Ultrasound elasticity imaging has been developed over the last decade to estimate tissue stiffness. Shear wave elasticity imaging (SWEI) quantifies tissue stiffness by measuring the speed of propagating shear waves following acoustic radiation force excitation. This paper presents the sequencing and data processing protocols of SWEI using a Verasonics system. The selection of the sequence parameters in a Verasonics programming script is discussed in detail. The data processing pipeline to calculate group shear wave speed (SWS), including tissue motion estimation, data filtering, and SWS estimation, is demonstrated...
January 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Bjørn Hafskjold
A binary isotope mixture of Lennard-Jones/spline particles at equilibrium was perturbed by a sudden change in the system's boundary temperatures. The system's response was determined by non-equilibrium molecular dynamics (NEMD). Three transient processes were studied: 1) The propagation of a pressure (shock) wave, 2) heat diffusivity and conduction, and 3) thermal diffusion (the Ludwig-Soret effect). These three processes occur at different time scales, which makes it possible to separate them in one single NEMD run...
January 2017: European Physical Journal. E, Soft Matter
Fabien Sauvet, Pierrick J Arnal, Pierre Emmanuel Tardo-Dino, Catherine Drogou, Pascal Van Beers, Clément Bougard, Arnaud Rabat, Garance Dispersyn, Alexandra Malgoyre, Damien Leger, Danielle Gomez-Merino, Mounir Chennaoui
BACKGROUND: Sleep loss is a risk factor for cardiovascular events mediated through endothelial dysfunction. AIMS: To determine if 7weeks of exercise training can limit cardiovascular dysfunction induced by total sleep deprivation (TSD) in healthy young men. METHODS: 16 subjects were examined during 40-h TSD, both before and after 7weeks of interval exercise training. Vasodilatation induced by ACh, insulin and heat (42°C) and pulse wave velocity (PWV), blood pressure and heart rate (HR) were assessed before TSD (controlday), during TSD, and after one night of sleep recovery...
January 5, 2017: International Journal of Cardiology
Jihoon Jung, Christopher K Uejio
Social network services (SNSs) may benefit public health by augmenting surveillance and distributing information to the public. In this study, we collected Twitter data focusing on six different heat-related themes (air conditioning, cooling center, dehydration, electrical outage, energy assistance, and heat) for 182 days from May 7 to November 3, 2014. First, exploratory linear regression associated outdoor heat exposure to the theme-specific tweet counts for five study cities (Los Angeles, New York, Chicago, Houston, and Atlanta)...
January 11, 2017: International Journal of Biometeorology
Yi Pan, Zhihong Luo, Yih-Chung Chang, Kai-Chung Lau, C Y Ng
The ionization energies (IEs) of TiO and TiO2 and the 0 K bond dissociation energies (D0) and the heats of formation at 0 K (ΔH°f0) and 298 K (ΔH°f298) for TiO/TiO(+) and TiO2/TiO2(+) are predicted by the wave-function-based CCSDTQ/CBS approach. The CCSDTQ/CBS calculations involve the approximation to the complete basis set (CBS) limit at the coupled cluster level up to full quadruple excitations along with the zero-point vibrational energy (ZPVE), high-order correlation (HOC), core-valence (CV) electronic, spin-orbit (SO) coupling, and scalar relativistic (SR) effect corrections...
January 11, 2017: Journal of Physical Chemistry. A
Matthias B Jungfleisch, Junjia Ding, Wei Zhang, Wanjun Jiang, John E Pearson, Valentine Novosad, Axel Hoffmann
Magnetic insulators, such as yttrium iron garnet (Y3Fe5O12), are ideal materials for ultralow power spintronics applications due to their low energy dissipation and efficient spin current generation and transmission. Recently, it has been realized that spin dynamics can be driven very effectively in micrometer-sized Y3Fe5O12/Pt heterostructures by spin-Hall effects. We demonstrate here the excitation and detection of spin dynamics in Y3Fe5O12/Pt nanowires by spin-torque ferromagnetic resonance. The nanowires defined via electron-beam lithography are fabricated by conventional room temperature sputtering deposition on Gd3Ga5O12 substrates and lift-off...
January 11, 2017: Nano Letters
Valdemar Stankevič, Gediminas Račiukaitis, Francesca Bragheri, Xuewen Wang, Eugene G Gamaly, Roberto Osellame, Saulius Juodkazis
Understanding of material behaviour at nanoscale under intense laser excitation is becoming critical for future application of nanotechnologies. Nanograting formation by linearly polarised ultra-short laser pulses has been studied systematically in fused silica for various pulse energies at 3D laser printing/writing conditions, typically used for the industrial fabrication of optical elements. The period of the nanogratings revealed a dependence on the orientation of the scanning direction. A tilt of the nanograting wave vector at a fixed laser polarisation was also observed...
January 9, 2017: Scientific Reports
Maryam Talebi, Milad Setareh, Majid Saffar-Avval, Reza Hosseini Abardeh
Application of ultrasonic waves for heat transfer augmentation has been proposed in the last few decades. Due to limited researches on acoustic streaming induced by ultrasonic oscillation, the effect of ultrasonic waves on natural convection heat transfer is the main purpose of this paper. At first, natural convection on up-ward-facing heating surface in a cylindrical enclosure filled with air is investigated numerically by the finite difference method, then the effect of upper surface oscillation on convection heat transfer is considered...
December 18, 2016: Ultrasonics
Michael F Faulkner, Steven T Bramwell, Peter C W Holdsworth
The two-dimensional harmonic XY (HXY) model is a spin model in which the classical spins interact via a piecewise parabolic potential. We argue that the HXY model should be regarded as the canonical classical lattice spin model of phase fluctuations in two-dimensional condensates, as it is the simplest model that guarantees the modular symmetry of the experimental systems. Here we formulate a lattice electric-field representation of the HXY model and contrast this with an analogous representation of the Villain model and the two-dimensional Coulomb gas with a purely rotational auxiliary field...
January 6, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Changyou Zhan, Weiping Wang, Claudia Santamaria, Bruce Wang, Alina Rwei, Brian P Timko, Daniel S Kohane
An injectable local anesthetic producing repeatable on-demand nerve block would be desirable for pain management. Here we present a phototriggerable device to achieve repeatable and adjustable on-demand local anesthesia in superficial or deep tissues, consisting of gold nanorods attached to low temperature sensitive liposomes (LTSL). The particles were loaded with tetrodotoxin and dexmedetomidine. Near-infrared light (NIR, 808 nm, continuous wave) could heat gold nanorods at low fluence (short duration and low irradiance), leading to rapid release of payload...
January 6, 2017: Nano Letters
Frank Chidawanyika, Casper Nyamukondiwa, Lorraine Strathie, Klaus Fischer
Temperature and resource availability are key elements known to limit the occurrence and survival of arthropods in the wild. In the current era of climate change, critical thermal limits and the factors affecting these may be of particular importance. We therefore investigated the critical thermal maxima (CTmax) of adult Zygogramma bicolorata beetles, a biological control agent for the invasive plant Parthenium hysterophorus, in relation to thermal acclimation, hardening, age, and food availability using static (constant) and dynamic (ramping) protocols...
2017: PloS One
Antonella Rossati
Since the mid-19th century, human activities have increased greenhouse gases such as carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere that resulted in increased average temperature. The effects of rising temperature include soil degradation, loss of productivity of agricultural land, desertification, loss of biodiversity, degradation of ecosystems, reduced fresh-water resources, acidification of the oceans, and the disruption and depletion of stratospheric ozone. All these have an impact on human health, causing non-communicable diseases such as injuries during natural disasters, malnutrition during famine, and increased mortality during heat waves due to complications in chronically ill patients...
January 2017: International Journal of Occupational and Environmental Medicine
Evren Ozcinar, Mehmet Cakici, Oktay Korun, Unsal Han, Ugursay Kiziltepe
BACKGROUND: The aim of this study was to evaluate the heat induced damage at the saphenofemoral junction level according to histopathological changes after radiofrequency or 1,470 nm radial tip laser ablation. PATIENTS AND METHODS: Varicose vein segments of 6-10 mm in diameter were exposed to radiofrequency (Closure Fast catheter, 7 cm heat segment, one cycle, 15 seconds, 10 Watt, 120 °C) or laser ablation (1,470 nm radial tip, continuous wave, vein diameter: 6 cm/8 cm/10 cm-power: 10 Watt-pullback speed: 2...
January 3, 2017: VASA. Zeitschrift Für Gefässkrankheiten
Pavel V Zinin, Vitali B Prakapenka, Katherine Burgess, Shoko Odake, Nikolay Chigarev, Shiv K Sharma
We developed a multi-functional in situ measurement system under high pressure equipped with a laser ultrasonics (LU) system, Raman device, and laser heating system (LU-LH) in a diamond anvil cell (DAC). The system consists of four components: (1) a LU-DAC system (probe and pump lasers, photodetector, and oscilloscope) and DAC; (2) a fiber laser, which is designed to allow precise control of the total power in the range from 2 to 100 W by changing the diode current, for heating samples; (3) a spectrometer for measuring the temperature of the sample (using black body radiation), fluorescence spectrum (spectrum of the ruby for pressure measurement), and Raman scattering measurements inside a DAC under high pressure and high temperature (HPHT) conditions; and (4) an optical system to focus laser beams on the sample and image it in the DAC...
December 2016: Review of Scientific Instruments
A Fleming, C Folsom, C Jensen, H Ban
A new fiber-based modulated optical reflectance configuration is developed in this work. The technique maintains the fiber-based heating laser (pump) and detection laser (probe) in close proximity at a fixed separation distance in a ceramic ferrule. The pump beam periodically heats the sample inducing thermal waves into the sample. The probe beam measures the temperature response at a known distance from the pump beam over a range of heating modulation frequencies. The thermal diffusivity of the sample may be calculated from the phase response between the input heat flux and the temperature response of a sample having a reflective surface...
December 2016: Review of Scientific Instruments
M Mehdi Jadidi, Ryan J Suess, Cheng Tan, Xinghan Cai, Kenji Watanabe, Takashi Taniguchi, Andrei B Sushkov, Martin Mittendorff, James Hone, H Dennis Drew, Michael S Fuhrer, Thomas E Murphy
Hot electron effects in graphene are significant because of graphene's small electronic heat capacity and weak electron-phonon coupling, yet the dynamics and cooling mechanisms of hot electrons in graphene are not completely understood. We describe a novel photocurrent spectroscopy method that uses the mixing of continuous-wave lasers in a graphene photothermal detector to measure the frequency dependence and nonlinearity of hot-electron cooling in graphene as a function of the carrier concentration and temperature...
December 16, 2016: Physical Review Letters
Takashi Yamamoto, Masahiro Sakata
Introduction: Radio waves and lasers can be used as heat sources during endovenous thermal ablation (EVTA) for saphenous vein insufficiency. A morphological comparison of veins that had been treated with EVTA was performed between those treated with an endovenous closure system (a radiofrequency [RF] system) and those treated with a Radial 2Ring fiber connected to a 1470-nm laser generator (2R). Methods: The experiment was conducted in a system that reproduces the physiological conditions found in the saphenous veins during EVTA...
2016: Annals of Vascular Diseases
Honglang Duan, Jianping Wu, Guomin Huang, Shuangxi Zhou, Wenfei Liu, Yingchun Liao, Xue Yang, Zufei Xiao, Houbao Fan
Heat waves in combination with drought are predicted to occur more frequently with climate warming, yet their interactive effects on crop carbon and water balance are still poorly understood. Hence, research on the capacity of crops to withstand and recover from the combined stress is urgently needed. This study investigated the effects of drought and heat wave on a crop species as well as the recovery from the combined stress. Seedlings were grown in growth chambers under two soil water conditions (i.e. well watered and drought stress) at ambient temperature (26°C) for 10 days...
December 22, 2016: AoB Plants
Simão Nóbrega, Pedro J Coelho
A thermal therapy for cancer in skin tissue is numerically investigated using three bioheat conduction models, namely Pennes, thermal wave and dual-phase lag models. A laser is applied at the surface of the skin for cancer ablation, and the temperature and thermal damage distributions are predicted using the three bioheat models and two different modeling approaches of the laser effect. The first one is a prescribed surface heat flux, in which the tissue is assumed to be highly absorbent, while the second approach is a volumetric heat source, which is reasonable if the scattering and absorption skin effects are of similar magnitude...
January 2017: Journal of Thermal Biology
Alejandro Bañón Navarro, Bogdan Teaca, Daniel Told, Daniel Groselj, Paul Crandall, Frank Jenko
We analyze plasma heating in weakly collisional kinetic Alfvén wave turbulence using high resolution gyrokinetic simulations spanning the range of scales between the ion and the electron gyroradii. Real space structures that have a higher than average heating rate are shown not to be confined to current sheets. This novel result is at odds with previous studies, which use the electromagnetic work in the local electron fluid frame, i.e., J·(E+v_{e}×B), as a proxy for turbulent dissipation to argue that heating follows the intermittent spatial structure of the electric current...
December 9, 2016: Physical Review Letters
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