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Cold laser

Paul Fourmont, Luis-Felipe Gerlein, Francois-Xavier Fortier, Sylvain G Cloutier, Riad Nechache
Thermoelectric Bi2Te3 and Sb2Te3 thin films with high power factor were successfully obtained by pulsed laser deposition (PLD). Here we demonstrate a well-controlled deposition of Bi2Te3/Sb2Te3 structures on glass substrates, through a shadow mask with micrometer scale features. We stablish an optimal growth temperature of 45 °C to attain compounds with suitable stoichiometric composition, structural and electrical properties, to achieve high thermoelectric power factor. These films are produced without additional post-annealing treatment or added gasses...
February 20, 2018: ACS Applied Materials & Interfaces
A V Strobel, H Tankisi, N B Finnerup, A Fuglsang-Frederiksen, P Jennum, K B Svendsen, F I Kirov, M Otto
BACKGROUND: Idiopathic REM sleep behaviour disorder (iRBD) has been recognised as a significant biomarker for developing a neurodegenerative alpha-synucleinopathy, which is why iRBD is considered to be a prodromal state for alpha-synucleinopathies including Parkinson's disease (PD). Many patients with PD suffer from complaints of pain and present impaired somatosensory function. We hypothesized that pain perception and somatosensory function could be altered already in a preclinical stage of PD including iRBD...
February 2018: Sleep Medicine
Jack D Wilkinson, Sarah A Leggett, Elizabeth J Marjanovic, Tonia L Moore, John Allen, Marina E Anderson, Jason Britton, Maya H Buch, Francesco Del Galdo, Christopher P Denton, Graham Dinsdale, Bridgett Griffiths, Frances Hall, Kevin Howell, Audrey MacDonald, Neil J McHugh, Joanne B Manning, John D Pauling, Christopher Roberts, Jacqueline A Shipley, Ariane L Herrick, Andrea K Murray
BACKGROUND: Objective and reliable outcome measures to facilitate clinical trials of novel treatments for systemic sclerosis (SSc)-related Raynaud's phenomenon (RP) are badly needed. Laser speckle contrast imaging (LSCI) and thermography are non-invasive measures of perfusion that show excellent potential. The purpose of this multi-centre study was to determine the reliability and validity of a hand cold challenge protocol using LSCI, standard thermography and low-cost mobile phone-based thermography...
February 18, 2018: Arthritis & Rheumatology
Jennifer A Noble, Michel Broquier, Gilles Grégoire, Satchin Soorkia, Gustavo Pino, Ernesto Marceca, Claude Dedonder-Lardeux, Christophe Jouvet
Experimental and theoretical investigations of the excited states of protonated 1- and 2-aminonaphthalene are presented. The electronic spectra are obtained by laser induced photofragmentation of the ions captured in a cold ion trap. Using ab initio calculations, the electronic spectra can be assigned to different tautomers which have the proton on the amino group or on the naphthalene moiety. It is shown that the tautomer distribution can be varied by changing the electrospray source conditions, favoring either the most stable form in solution (amino protonation) or that in the gas phase (aromatic ring protonation)...
February 16, 2018: Physical Chemistry Chemical Physics: PCCP
Zhang Jing, Kong Dejun
A cold sprayed Al coating on S355 structural steel was processed using a laser remelting (LR). The surface and cross-section morphologies, chemical compositions, and phases of as-obtained Al coating before and after LR were analyzed using a scanning electronic microscope (SEM), energy dispersive spectrometer (EDS), and X-ray diffractometer (XRD), respectively, and their hardness was measured using a micro-hardness tester. The friction-wear behaviors of Al coating before and after LR in 3.5% NaCl solution were conducted to simulate the sand and gravel scouring on its surface in seawater, the effects of wear loads and speeds on the tribological properties of Al coating were analyzed, and the wear mechanisms under different wear loads and speeds were also discussed...
February 11, 2018: Materials
Jingjing Ju, Haiyi Sun, Xingkai Hu, Yonghong Liu, Yaoxiang Liu, Jingwei Wang, Cheng Wang, Tie-Jun Wang, Xueliang Guo, Jiansheng Liu, See Leang Chin, Ruxin Li, Zhizhan Xu
Water condensation and precipitation induced by 22-TW 800-nm laser pulses at 1 Hz in an open cloud chamber were investigated in a time-resolved manner. Two parts of precipitation in two independent periods of time were observed directly following each laser shot. One part started around the filament zone at t < 500 μs and ended at t ≅ 1.5 ms after the arrival of the femtosecond laser pulse. The other following the laser-induced energetic air motion (turbulence), started at t ≅ 20 ms and ended at t ≅ 120 ms...
February 5, 2018: Optics Express
Waseem Aboulela, Mohammed S ElSheemy, Mahmoud Shoukry, Ahmed M Shouman, Ahmed I Shoukry, Waleed Ghoneima, Mohamed El Ghoneimy, Hany A Morsi, Mostafa Abdel Mohsen, Hesham Badawy
PURPOSE: To compare efficacy and safety of visual internal urethrotomy (VIU) using holmium laser (Ho:YAG) (group A) versus cold knife (group B) in children with urethral strictures. It may be the first comparative study on this issue in children. METHODS: This study compared Ho:YAG group, which was evaluated prospectively from January 2014 till January 2016, versus cold knife group, which was a historical control performed from March 2008 till February 2010. Children ≤ 13 years old with urethral strictures ≤ 1...
February 3, 2018: International Urology and Nephrology
Islam A Ramadan, Hélène Bailliet, Jean-Christophe Valière
The influence of both the natural convection and end-effects on Rayleigh streaming pattern in a simple standing-wave thermoacoustic engine is investigated experimentally at different acoustic levels. The axial mean velocity inside the engine is measured using both Laser Doppler Velocimetry and Particle Image Velocimetry. The mean flow patterns are categorized in three different regions referred to as "cold streaming" region, "hot streaming" region, and "end-effects" region. In the cold streaming region, the dominant phenomenon is Rayleigh streaming and the mean velocity measurements correspond well with the theoretical expectations of Rayleigh streaming at low acoustic levels...
January 2018: Journal of the Acoustical Society of America
Gang Zhao, Jingyi Mi, Yongjun Rui, Xiaoyun Pan, Qun Yao, Yang Qiu
Cold intolerance is a common complication of digital replantation. The exact etiology is unclear, but it is considered to be multifactorial, including nonsurgical characteristics, vascular, and neurologic conditions. Blood flow may play a significant role in cold intolerance. This study was designed to evaluate the correlation of digital blood flow, including volumetric flow rate (VFR) and skin blood flow (SkBF), with cold intolerance in replanted fingers.A retrospective study was conducted among patients who underwent digital replantation between 2010 and 2013...
December 2017: Medicine (Baltimore)
Jamie Vovrosh, Georgios Voulazeris, Plamen G Petrov, Ji Zou, Youssef Gaber, Laura Benn, David Woolger, Moataz M Attallah, Vincent Boyer, Kai Bongs, Michael Holynski
Recent advances in the understanding and control of quantum technologies, such as those based on cold atoms, have resulted in devices with extraordinary metrological performance. To realise this potential outside of a lab environment the size, weight and power consumption need to be reduced. Here we demonstrate the use of laser powder bed fusion, an additive manufacturing technique, as a production technique relevant to the manufacture of quantum sensors. As a demonstration we have constructed two key components using additive manufacturing, namely magnetic shielding and vacuum chambers...
January 31, 2018: Scientific Reports
Heather C Massey, James R House, Michael J Tipton
INTRODUCTION: This study investigated skin vasomotor responses in the fingers and toes during cooling and rewarming with and without normobaric hypoxia. METHODS: Fourteen volunteers (8 males and 6 females) were exposed to gradual air cooling (mean±SD: -0.4±0.1oC·min-1) followed by rewarming (+0.5±0.1oC·min-1) while breathing normoxic air (FIO2 0.21 at 761±3 mm Hg) or hypoxic gas (FIO2 0.12, at 761±3 mm Hg, equivalent to ~5000 m above sea level). Throughout the gradual cooling and rewarming phases, rectal temperature was measured, and skin temperatures and laser Doppler skin blood flow were measured on the thumb, little finger, and great and little toe pads...
January 16, 2018: Wilderness & Environmental Medicine
Pierre Vernaz-Gris, Kun Huang, Mingtao Cao, Alexandra S Sheremet, Julien Laurat
Quantum memory for flying optical qubits is a key enabler for a wide range of applications in quantum information. A critical figure of merit is the overall storage and retrieval efficiency. So far, despite the recent achievements of efficient memories for light pulses, the storage of qubits has suffered from limited efficiency. Here we report on a quantum memory for polarization qubits that combines an average conditional fidelity above 99% and efficiency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost...
January 25, 2018: Nature Communications
Sara Rosi, Alessia Burchianti, Stefano Conclave, Devang S Naik, Giacomo Roati, Chiara Fort, Francesco Minardi
Laser cooling based on dark states, i.e. states decoupled from light, has proven to be effective to increase the phase-space density of cold trapped atoms. Dark-states cooling requires open atomic transitions, in contrast to the ordinary laser cooling used for example in magneto-optical traps (MOTs), which operate on closed atomic transitions. For alkali atoms, dark-states cooling is therefore commonly operated on the D1 transition nS1/2 → nP1/2. We show that, for 87Rb, thanks to the large hyperfine structure separations the use of this transition is not strictly necessary and that "quasi-dark state" cooling is efficient also on the D2 line, 5S1/2 → 5P3/2...
January 22, 2018: Scientific Reports
Tamar Goldzak, Alexei A Mailybaev, Nimrod Moiseyev
Almost twenty years ago, light was slowed down to less than 10^{-7} of its vacuum speed in a cloud of ultracold atoms of sodium. Upon a sudden turn-off of the coupling laser, a slow light pulse can be imprinted on cold atoms such that it can be read out and converted into a photon again. In this process, the light is stopped by absorbing it and storing its shape within the atomic ensemble. Alternatively, the light can be stopped at the band edge in photonic-crystal waveguides, where the group speed vanishes...
January 5, 2018: Physical Review Letters
Joanne N Caldwell, Anne M J van den Heuvel, Pete Kerry, Mitchell J Clark, Gregory E Peoples, Nigel A S Taylor
Physiologically trivial time differences for cooling the intrathoracic viscera of hyperthermic individuals have been reported between cold- and temperate-water immersion treatments. One explanation for that observation is reduced convective heat delivery to the skin during cold immersion, and this experiment was designed to test both the validity of that observation, and its underlying hypothesis. Eight healthy males participated in four head-out, water immersions: two when normothermic, and two following exercise-induced, moderate-profound hyperthermia...
January 18, 2018: Experimental Physiology
Bernadett Mosdósi, Zoltán Nyul, Arnold Nagy, Kata Bölcskei, Tamás Decsi, Zsuzsanna Helyes
This is the first report describing a severe form of cold agglutinin-induced acrocyanosis with cutaneous necrosis after Mycoplasma infection in a 9-year-old patient without any other severe symptoms and laboratory alterations. We also present the results of two non-invasive methods used to determine the viability of tissues, degree of tissue perfusion impairment, and the responsiveness of the microvasculature. Laser Doppler flowmetry and laser speckle contrast imaging, both suitable to measure tissue blood perfusion non-invasively, have been used in the diagnosis and follow-up of various peripheral vascular diseases...
December 31, 2017: Croatian Medical Journal
F Houdellier, G M Caruso, S Weber, M Kociak, A Arbouet
We report on the development of an ultrafast Transmission Electron Microscope based on a cold field emission source which can operate in either DC or ultrafast mode. Electron emission from a tungsten nanotip is triggered by femtosecond laser pulses which are tightly focused by optical components integrated inside a cold field emission source close to the cathode. The properties of the electron probe (brightness, angular current density, stability) are quantitatively determined. The measured brightness is the largest reported so far for UTEMs...
December 27, 2017: Ultramicroscopy
Sun Ae Hwang, Chi Dae Kim, Won Suk Lee
In this study, we aimed to investigate the neuroprotective effects of caffeic acid phenethyl ester (CAPE), an active component of propolis purified from honeybee hives, on photothrombotic cortical ischemic injury in mice. Permanent focal ischemia was achieved in the medial frontal and somatosensory cortices of anesthetized male C57BL/6 mice by irradiation of the skull with cold light laser in combination with systemic administration of rose bengal. The animals were treated with CAPE (0.5-5 mg/kg, i.p.) twice 1 and 6 h after ischemic insult...
January 2018: Korean Journal of Physiology & Pharmacology
P C Schmid, J Greenberg, M I Miller, K Loeffler, H J Lewandowski
Trapping molecular ions that have been sympathetically cooled with laser-cooled atomic ions is a useful platform for exploring cold ion chemistry. We designed and characterized a new experimental apparatus for probing chemical reaction dynamics between molecular cations and neutral radicals at temperatures below 1 K. The ions are trapped in a linear quadrupole radio-frequency trap and sympathetically cooled by co-trapped, laser-cooled, atomic ions. The ion trap is coupled to a time-of-flight mass spectrometer to readily identify product ion species and to accurately determine trapped ion numbers...
December 2017: Review of Scientific Instruments
Marko Förstel, Bertram K A Jaeger, Wolfgang Schewe, Philipp H A Sporkhorst, Otto Dopfer
We describe two improvements to an existing tandem mass spectrometer coupled to a laser vaporization cluster ion source suitable for photodissociation spectroscopy: (i) cooling of the cluster source nozzle and (ii) mass selection prior to the photodissociation region via replacing an octupole ion guide by a quadrupole mass spectrometer. The improved sensitivity and transmission enable the production of larger heteroatomic clusters as well as rare gas solvated clusters. We present two examples demonstrating the new capabilities of the improved setup...
December 2017: Review of Scientific Instruments
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