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Intense pulsed light

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https://www.readbyqxmd.com/read/28446222/effect-of-quantity-and-intensity-of-pulsed-light-on%C3%A2-human-non-visual-physiological-responses
#1
Qianying Dai, Yuria Uchiyama, Soomin Lee, Yoshihiro Shimomura, Tetsuo Katsuura
BACKGROUND: Exposure to pulsed light results in non-visual physiological responses in humans. The present study aims to investigate whether such non-visual effects are influenced to a greater extent by the intensity of lighting or by the power (quantity) of lighting. METHODS: >Twelve healthy young male participants (23 ± 0.3 years, 21-24 age range) were recruited for the present study. Participants were exposed to light of varying levels of intensity and quantity whose frequency was held constant across the conditions, which consisted of exposure to blue (different intensity, constant quantity) and white (constant intensity, different quantity) LEDs...
April 26, 2017: Journal of Physiological Anthropology
https://www.readbyqxmd.com/read/28441328/a-gradient-field-pulsed-eddy-current-probe-for-evaluation-of-hidden-material-degradation-in-conductive-structures-based-on-lift-off-invariance
#2
Yong Li, Haoqing Jing, Ilham Mukriz Zainal Abidin, Bei Yan
Coated conductive structures are widely adopted in such engineering fields as aerospace, nuclear energy, etc. The hostile and corrosive environment leaves in-service coated conductive structures vulnerable to Hidden Material Degradation (HMD) occurring under the protection coating. It is highly demanded that HMD can be non-intrusively assessed using non-destructive evaluation techniques. In light of the advantages of Gradient-field Pulsed Eddy Current technique (GPEC) over other non-destructive evaluation methods in corrosion evaluation, in this paper the GPEC probe for quantitative evaluation of HMD is intensively investigated...
April 25, 2017: Sensors
https://www.readbyqxmd.com/read/28438002/hot-luminescence-from-gold-nanoflowers-and-its-application-in-high-density-optical-data-storage
#3
Yunbao Zheng, Haiying Liu, Jin Xiang, Qiaofeng Dai, Min Ouyang, Shaolong Tie, Sheng Lan
Gold nanoflowers with feature sizes ranging from several tenths to several hundred nanometers were synthesized by using the one-pot method. They were formed by the self-organization of gold nanoparticles of several nanometers and exhibited broad extinction spectra in the near infrared spectral range. Randomly distributed hot spots originating from the strongly localized modes were generated in gold nanoflowers and their appearances exhibited strong dependences on both the polarization and wavelength of the excitation light...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28434049/a-prospective-study-of-the-safety-and-efficacy-of-a-combined-bipolar-radiofrequency-intense-pulsed-light-and-infrared-diode-laser-treatment-for-global-facial-photoaging
#4
Min Jiang, Fang Yan, Mathew Avram, Zhong Lu
The clinical features of photoaging include: skin texture changes, laxity, rhytides, pigmentary changes, and vascular changes such as erythema and telangiectasias. In order to meet patients' increasing demands for improving all aspects of photoaging at one office visit, employing a multi-modality treatment for all aspects of photoaging has become increasingly desirable for the physician and patient alike. We examine a novel device that employs bipolar radiofrequency (RF), intense pulsed light (IPL), and infrared diode laser...
April 23, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28418076/ultrasonic-modulation-of-tissue-optical-properties-in-ex-vivo-porcine-skin-to-improve-transmitted-transdermal-laser-intensity
#5
Paul J D Whiteside, Chenxi Qian, Nicholas Golda, Heather K Hunt
BACKGROUND AND OBJECTIVE: Applications of light-based energy devices involving optical targets within the dermis frequently experience negative side-effects resultant from surface scattering and excess optical absorption by epidermal melanin. As a broadband optical absorber, melanin decreases the efficacy of light-based treatments throughout the ultraviolet, visible, and near-infrared spectra while also generating additional heat within the surface tissue that can lead to inflammation or tissue damage...
April 18, 2017: Lasers in Surgery and Medicine
https://www.readbyqxmd.com/read/28415211/dynamics-of-vortex-antivortex-pairs-and-rarefaction-pulses-in-liquid-light
#6
David Feijoo, Angel Paredes, Humberto Michinel
We present a numerical study of the cubic-quintic nonlinear Schrödinger equation in two transverse dimensions, relevant for the propagation of light in certain exotic media. A well-known feature of the model is the existence of flat-top bright solitons of fixed intensity, whose dynamics resembles the physics of a liquid. They support traveling wave solutions, consisting of rarefaction pulses and vortex-antivortex pairs. In this work, we demonstrate how the vortex-antivortex pairs can be generated in bright soliton collisions displaying destructive interference followed by a snake instability...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28414231/organic-phosphorescence-nanowire-lasers
#7
Zhenyi Yu, Yishi Wu, Lu Xiao, Jianwei Chen, Qing Liao, Jiannian Yao, Hongbing Fu
Organic solid-state lasers (OSSLs) based on singlet fluorescence have merited intensive study as an important class of light sources. Although the use of triplet phosphors has led to 100% internal quantum efficiency in organic light-emitting diodes (OLEDs), stumbling blocks in triplet lasing include generally forbidden intersystem crossing (ISC) and a low quantum yield of phosphorescence (ΦP). Here, we reported the first triplet-phosphorescence OSSL from a nanowire microcavity of a sulfide-substituted difluoroboron compound...
April 25, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28411595/infrared-absorption-of-methanol-water-clusters-ch3oh-n-h2o-n-1-4-recorded-with-the-vuv-ionization-ir-depletion-technique
#8
Yu-Fang Lee, Anne-Marie Kelterer, Gergely Matisz, Sándor Kunsági-Máté, Chao-Yu Chung, Yuan-Pern Lee
We recorded infrared (IR) spectra in the CH- and OH-stretching regions of size-selected clusters of methanol (M) with one water molecule (W), represented as MnW, n = 1-4, in a pulsed supersonic jet using the photoionization/IR-depletion technique. Vacuum ultraviolet emission at 118 nm served as the source of ionization in a time-of-flight mass spectrometer to detect clusters MnW as protonated forms Mn-1WH(+). The variations in intensities of Mn-1WH(+) were monitored as the wavelength of the IR laser light was tuned across the range 2700-3800 cm(-1)...
April 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28403199/the-plastoquinone-pool-of-nannochloropsis-oceanica-is-not-completely-reduced-during-bright-light-pulses
#9
Gunvor Røkke, Thor Bernt Melø, Martin Frank Hohmann-Marriott
The lipid-producing model alga Nannochloropsis oceanica has a distinct photosynthetic machinery. This organism possesses chlorophyll a as its only chlorophyll species, and has a high ratio of PSI to PSII. This high ratio of PSI to PSII may affect the redox state of the plastoquinone pool during exposure to light, and consequently may play a role in activating photoprotection mechanisms. We utilized pulse-amplitude modulated fluorometry to investigate the redox state of the plastoquinone pool during and after bright light pulses...
2017: PloS One
https://www.readbyqxmd.com/read/28398334/diffraction-data-of-core-shell-nanoparticles-from-an-x-ray-free-electron-laser
#10
Xuanxuan Li, Chun-Ya Chiu, Hsiang-Ju Wang, Stephan Kassemeyer, Sabine Botha, Robert L Shoeman, Robert M Lawrence, Christopher Kupitz, Richard Kirian, Daniel James, Dingjie Wang, Garrett Nelson, Marc Messerschmidt, Sébastien Boutet, Garth J Williams, Elisabeth Hartmann, Aliakbar Jafarpour, Lutz M Foucar, Anton Barty, Henry Chapman, Mengning Liang, Andreas Menzel, Fenglin Wang, Shibom Basu, Raimund Fromme, R Bruce Doak, Petra Fromme, Uwe Weierstall, Michael H Huang, John C H Spence, Ilme Schlichting, Brenda G Hogue, Haiguang Liu
X-ray free-electron lasers provide novel opportunities to conduct single particle analysis on nanoscale particles. Coherent diffractive imaging experiments were performed at the Linac Coherent Light Source (LCLS), SLAC National Laboratory, exposing single inorganic core-shell nanoparticles to femtosecond hard-X-ray pulses. Each facetted nanoparticle consisted of a crystalline gold core and a differently shaped palladium shell. Scattered intensities were observed up to about 7 nm resolution. Analysis of the scattering patterns revealed the size distribution of the samples, which is consistent with that obtained from direct real-space imaging by electron microscopy...
April 11, 2017: Scientific Data
https://www.readbyqxmd.com/read/28389668/photoacoustic-imaging-reveals-hidden-underdrawings-in-paintings
#11
George J Tserevelakis, Ilianna Vrouvaki, Panagiotis Siozos, Krystallia Melessanaki, Kostas Hatzigiannakis, Costas Fotakis, Giannis Zacharakis
A novel, non-invasive, imaging methodology, based on the photoacoustic effect, is introduced in the context of artwork diagnostics with emphasis on the uncovering of hidden features such as underdrawings or original sketch lines in paintings. Photoacoustic microscopy, a rapidly growing imaging method widely employed in biomedical research, exploits the ultrasonic acoustic waves, generated by light from a pulsed or intensity modulated source interacting with a medium, to map the spatial distribution of absorbing components...
April 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28388046/nonresonant-raman-effects-on-femtosecond-pump-probe-with-chirped-white-light-challenges-and-opportunities
#12
Itay Gdor, Tufan Ghosh, Oleg Lioubashevski, Sanford Ruhman
Impulsive Raman excitation in neat organic liquids far from resonance is followed using chirped broad-band supercontinuum probe pulses. Spectral modulations due to impulsively induced coherent vibrations vary in intensity 10-fold as a function of the probe's linear chirp. Simulations clarify why the vibrational signature is maximized for a group delay dispersion (GDD) in reduced units of νvib(-2) = 0.5 while a probe GDD of twice that quenches the same spectral modulations. Accordingly, recent claims that chirped white-light probe pulses provide equivalent information on material response to their compressed analogues must be taken with caution...
April 20, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28386081/thz-electric-field-induced-second-harmonic-generation-in-inorganic-ferroelectric
#13
Kirill A Grishunin, Nikita A Ilyin, Natalia E Sherstyuk, Elena D Mishina, Alexey Kimel, Vladimir M Mukhortov, Andrey V Ovchinnikov, Oleg V Chefonov, Mikhail B Agranat
Second Harmonic Generation induced by the electric field of a strong nearly single-cycle terahertz pulse with the peak amplitude of 300 kV/cm is studied in a classical inorganic ferroelectric thin film of (Ba0.8Sr0.2)TiO3. The dependences of the SHG intensity on the polarization of the incoming light is revealed and interpreted in terms of electric polarization induced in the plane of the film. As the THz pulse pumps the medium in the range of phononic excitations, the induced polarization is explained as a dynamical change of the ferrolectric order parameter...
April 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28383017/room-temperature-subnanosecond-waveguide-lasers-in-nd-yvo4-q-switched-by-phase-change-vo2-a-comparison-with-2d-materials
#14
Weijie Nie, Rang Li, Chen Cheng, Yanxue Chen, Qingming Lu, Carolina Romero, Javier R Vázquez de Aldana, Xiaotao Hao, Feng Chen
We report on room-temperature subnanosecond waveguide laser operation at 1064 nm in a Nd:YVO4 crystal waveguide through Q-switching of phase-change nanomaterial vanadium dioxide (VO2). The unique feature of VO2 nanomaterial from the insulating to metallic phases offers low-saturation-intensity nonlinear absorptions of light for subnanosecond pulse generation. The low-loss waveguide is fabricated by using the femtosecond laser writing with depressed cladding geometry. Under optical pump at 808 nm, efficient pulsed laser has been achieved in the Nd:YVO4 waveguide, reaching minimum pulse duration of 690 ps and maximum output average power of 66...
April 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28382317/probing-ultra-fast-processes-with-high-dynamic-range-at-4th-generation-light-sources-arrival-time-and-intensity-binning-at-unprecedented-repetition-rates
#15
S Kovalev, B Green, T Golz, S Maehrlein, N Stojanovic, A S Fisher, T Kampfrath, M Gensch
Understanding dynamics on ultrafast timescales enables unique and new insights into important processes in the materials and life sciences. In this respect, the fundamental pump-probe approach based on ultra-short photon pulses aims at the creation of stroboscopic movies. Performing such experiments at one of the many recently established accelerator-based 4th-generation light sources such as free-electron lasers or superradiant THz sources allows an enormous widening of the accessible parameter space for the excitation and/or probing light pulses...
March 2017: Structural Dynamics (Melville, N.Y.)
https://www.readbyqxmd.com/read/28380905/broadband-2d-electronic-spectrometer-using-white-light-and-pulse-shaping-noise-and-signal-evaluation-at-1-and-100-khz
#16
Nicholas M Kearns, Randy D Mehlenbacher, Andrew C Jones, Martin T Zanni
We have developed a broad bandwidth two-dimensional electronic spectrometer that operates shot-to-shot at repetition rates up to 100 kHz using an acousto-optic pulse shaper. It is called a two-dimensional white-light (2D-WL) spectrometer because the input is white-light supercontinuum. Methods for 100 kHz data collection are studied to understand how laser noise is incorporated into 2D spectra during measurement. At 100 kHz, shot-to-shot scanning of the delays and phases of the pulses in the pulse sequence produces a 2D spectrum 13-times faster and with the same signal-to-noise as using mechanical stages and a chopper...
April 3, 2017: Optics Express
https://www.readbyqxmd.com/read/28377784/flowering-and-growth-responses-of-cultivated-lentil-and-wild-lens-germplasm-toward-the-differences-in-red-to-far-red-ratio-and-photosynthetically-active-radiation
#17
Hai Y Yuan, Shyamali Saha, Albert Vandenberg, Kirstin E Bett
Understanding environmental responses of pulse crop species and their wild relatives will play an important role in developing genetic strategies for crop improvement in response to changes in climate. This study examined how cultivated lentil and wild Lens germplasm responded to different light environments, specifically differences in red/far-red ratio (R/FR) and photosynthetically active radiation (PAR). Three genotypes of each the seven Lens species were grown in environmentally controlled growth chambers equipped to provide light treatments consisting of different R/FR ratios and PAR values...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28361886/enzyme-dependent-fluorescence-recovery-of-nadh-after-photobleaching-to-assess-dehydrogenase-activity-of-isolated-perfused-hearts
#18
Angel Moreno, Sarah Kuzmiak-Glancy, Rafael Jaimes, Matthew W Kay
Reduction of NAD(+) by dehydrogenase enzymes to form NADH is a key component of cellular metabolism. In cellular preparations and isolated mitochondria suspensions, enzyme-dependent fluorescence recovery after photobleaching (ED-FRAP) of NADH has been shown to be an effective approach for measuring the rate of NADH production to assess dehydrogenase enzyme activity. Our objective was to demonstrate how dehydrogenase activity could be assessed within the myocardium of perfused hearts using NADH ED-FRAP. This was accomplished using a combination of high intensity UV pulses to photobleach epicardial NADH...
March 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28352913/highly-durable-photochromic-radical-complexes-having-no-steric-protections-of-radicals
#19
Yoichi Kobayashi, Yasuhiro Mishima, Katsuya Mutoh, Jiro Abe
Steric protection groups are usually necessary for stable radicals. However, here, we developed novel photochromic radical complexes which generate sterically unprotected imidazolyl and phenoxyl radicals upon UV light irradiation based on the phenoxyl-imidazolyl radical complex (PIC) framework. These photochromic compounds show excellent durability against repeated irradiation of intense nanosecond laser pulses even in polar protic solvents, such as ethanol.
March 29, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28352605/photo-epilation-with-intense-pulsed-light-for-thinning-of-anterior-hairline-after-hairline-correction-surgery-in-east-asians
#20
Jae Hyun Park, Seung Yong Lee, Seung Hyun You, Na Rae Kim
BACKGROUND: Thin hairs are critical to achieve natural result in female hairline correction surgery. However, there are few studies on the usefulness of hair thinning by intense pulsed light (IPL) after hairline correction surgery in East Asian females. METHODS: Hair thinning using IPL was performed in 54 women who had complained about thick hairs along the frontal hairline after hairline correction surgery. Patient mean age was 31.2 years old and patients were an average of 2...
March 2017: Archives of Plastic Surgery
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