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Intense pulsed light

David Kingsley, Rafael E Perez-Perez, Glenn Boyd, Joseph Sites, Brendan A Niemira
AIM: The study aim was to evaluate the potential of 405 nm light as a virus intervention for blueberries. METHODS AND RESULTS: Tulane virus-inoculated-blueberries were treated with 4.2 mW/sq cm of 405 nm light for 5 to 30 min. To mitigate thermal heating due to the intense light, a dry ice-chilled nitrogen-based cooling system was utilized. Blueberries were rotated to ensure exposure of all surfaces to 405 light. Five, 10, and 30 min treatments resulted in little or no inactivation of Tulane virus on blueberries (average log reductions of -0...
November 16, 2017: Journal of Applied Microbiology
Lin Gao, Ni Gao, Wenting Song, Erle Dang, Rong Yin, Li Wang, Gang Wang
<p>Both pulsed dye laser (PDL) and intense pulsed light (IPL) systems have been demonstrated to be effective for treatment of facial telangiectasia, however there have been very few comparative studies between both treatments involving purely Asian patient populations. In this study, we performed a retrospective analysis to compare the efficacy of PDL and IPL systems for the treatment of facial telangiectasia. A total of 416 patients with facial telangiectasia who were treated by PDL or IPLs in our department from August 2012 to March 2015 were included in this study...
November 1, 2017: Journal of Drugs in Dermatology: JDD
Nickolai Zhavoronkov, Mikhail Ivanov
Attosecond (1  as=10(-18)  s) pulses produced through high harmonic generation (HHG) are a basis for studies of electron dynamics during light-matter interaction on an electron's natural time scale. Extensively exploited HHG technology has, however, a few unsolved problems, where producing of circularly polarized or chiral attosecond pulses belongs to them. We have demonstrated experimentally a way to control the ellipticity of attosecond pulse trains produced via HHG in two-color, bi-circular laser fields...
November 15, 2017: Optics Letters
E G Maksimov, N N Sluchanko, Y B Slonimskiy, E A Slutskaya, A V Stepanov, A M Argentova-Stevens, E A Shirshin, G V Tsoraev, K E Klementiev, O V Slatinskaya, E P Lukashev, T Friedrich, V Z Paschenko, A B Rubin
The 35-kDa Orange Carotenoid Protein (OCP) is responsible for photoprotection in cyanobacteria. It acts as a light intensity sensor and efficient quencher of phycobilisome excitation. Photoactivation triggers large-scale conformational rearrangements to convert OCP from the orange OCP(O) state to the red active signaling state, OCP(R), as demonstrated by various structural methods. Such rearrangements imply a complete, yet reversible separation of structural domains and translocation of the carotenoid. Recently, dynamic crystallography of OCP(O) suggested the existence of photocycle intermediates with small-scale rearrangements that may trigger further transitions...
November 14, 2017: Scientific Reports
Magdalena Ulmeanu, Robert L Harniman, Petko Petkov, Michael N R Ashfold
Single, or isolated small arrays of, spherical silica colloidal particles (with refractive index ncolloid = 1.47 and radius R = 350 nm or 1.5 μm) were placed on a silicon substrate and immersed in carbon tetrachloride (nliquid = 1.48) or toluene (nliquid = 1.52). Areas of the sample were then exposed to a single laser pulse (8 ps duration, wavelength λ = 355 nm), and the spatial intensity modulation of the near field in the vicinity of the particles revealed via the resulting patterning of the substrate surface...
November 14, 2017: Materials
Hamootal Duadi, Idit Feder, Dror Fixler
Near-infrared light allows measuring tissue oxygenation. These measurements relay on oxygenation dependent absorption spectral changes. However, the tissue scattering, which is also spectral dependent, introduces an intrinsic error. Most methods focus on the volume reflectance from a semi-infinite sample. We have proposed examining the full scattering profile (FSP), which is the angular intensity distribution. A point was found, i.e. the iso-pathlength (IPL) point, which is not dependent on the tissue scattering, and can serve for self-calibration...
November 13, 2017: Journal of Biophotonics
H Olof Jönsson, Carl Caleman, Jakob Andreasson, Nicuşor Tîmneanu
Serial femtosecond crystallography is an emerging and promising method for determining protein structures, making use of the ultrafast and bright X-ray pulses from X-ray free-electron lasers. The upcoming X-ray laser sources will produce well above 1000 pulses per second and will pose a new challenge: how to quickly determine successful crystal hits and avoid a high-rate data deluge. Proposed here is a hit-finding scheme based on detecting photons from plasma emission after the sample has been intercepted by the X-ray laser...
November 1, 2017: IUCrJ
Thomas Gaumnitz, Arohi Jain, Yoann Pertot, Martin Huppert, Inga Jordan, Fernando Ardana-Lamas, Hans Jakob Wörner
Attosecond metrology has so far largely remained limited to titanium:sapphire lasers combined with an active stabilization of the carrier-envelope phase (CEP). These sources limit the achievable photon energy to ∼100 eV which is too low to access X-ray absorption edges of most second- and third-row elements which are central to chemistry, biology and material science. Therefore, intense efforts are underway to extend attosecond metrology to the soft-X-ray (SXR) domain using mid-infrared (mid-IR) drivers. Here, we introduce and experimentally demonstrate a method that solves the long-standing problem of the complete temporal characterization of ultra-broadband (≫10 eV) attosecond pulses...
October 30, 2017: Optics Express
S Yue, V Wadia, N Sekula, P S Dickinson, R R Thompson
Elevations of sex steroids induced by social cues can rapidly modulate social behavior, but we know little about where they act within the nervous system to produce such effects. In male goldfish, testosterone (T) rapidly increases approach responses to the visual cues of females through its conversion to estradiol. Because aromatase is expressed in the retina, we tested if T can acutely influence retina responses to visual stimuli, and investigated the receptor mechanisms that may mediate such effects. Specifically, we measured FOS protein immunoreactivity to determine if T affects cellular responses to visual stimuli that include females, and used electrophysiology to investigate whether T can generally affect light sensitivity...
October 28, 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
S Huang, Y Ding, Y Feng, E Hemsing, Z Huang, J Krzywinski, A A Lutman, A Marinelli, T J Maxwell, D Zhu
A simple method for generating single-spike hard x-ray pulses in free-electron lasers (FELs) has been developed at the Linac Coherent Light Source (LCLS). This is realized by nonlinear bunch compression using 20-pC bunch charge, demonstrated in the hard x-ray regime at 5.6 and 9 keV, respectively. Measurements show about half of the FEL shots containing a single-spike spectrum. At 5.6-keV photon energy, the single-spike shots have a mean pulse energy of about 10  μJ with 70% intensity fluctuation and the pulse full width at half maximum is evaluated to be at 200-as level...
October 13, 2017: Physical Review Letters
Ping Zhang, Mei X Wu
Psoriasis is an autoimmune inflammatory skin disease. In the past several decades, phototherapy has been widely used to treat stable psoriatic lesions, including trunk, scalp, arms and legs, and partial nail psoriasis. A variety of light/lasers with different mechanisms of action have been developed for psoriasis including ultraviolet B (UVB), psoralen ultraviolet A (PUVA), pulsed dye laser (PDL), photodynamic therapy (PDT), intense pulsed light (IPL), light-emitting diodes (LED), and so on. Because light/laser each has specific therapeutic and adverse effects, it is important to adequately choose the sources and parameters in management of psoriasis with different pathogenic sites, severities, and duration of the disorder...
October 24, 2017: Lasers in Medical Science
Hea-Ja An, Kyung-Won Kim, Mun-Ho Ryu, Han-Yeong Oh, Nam-Gyun Kim, Kyoung-Jun Park
Low-level light (laser) therapy (LLLT) has been widely researched in the recent past. Existing LLLT studies were performed based on laser. Recently, studies using LED have increased. This study presents a smartphone-driven low-power light-emitting device for use in colour therapy as an alternative medicine. The device consists of a control unit and a colour probe. The device is powered by and communicates with a smartphone using USB On-The-Go (OTG) technology. The control unit controls emitting time and intensity of illumination with the configuration value of a smartphone application...
2017: Journal of Healthcare Engineering
Seung-Youl Lee, Cho-Long Ju, Tae-Hee Lee, Hyeon-Su Na, In-Su Lee, Chang-Won Park
This Intense pulsed light (IPL) is skin therapy medical device to remove infection and lesion. The market size of IPL has increased because of increasing device users such as doctors, nurses, engineers, patients. Thus, the number of IPL approvals by Ministry of Food and Drug Safety (MFDS) has increased. However, since there are no standard and guideline for evaluation of IPL performance and safety, it is need to develop the evaluation method of IPL performance and safety for petitioners and examiners who are having difficulties in approval and review...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Martin Lehr, Benjamin Foerster, Mathias Schmitt, Katja Krüger, Carsten Sönnichsen, Gerd Schönhense, Hans-Joachim Elmers
Electron emission by femtosecond laser pulses from individual Au nanorods is studied with a time-of-flight momentum resolving photoemission electron microscope (ToF k-PEEM). The Au nanorods adhere to a transparent indium-tin oxide substrate, allowing for illumination from the rear side at normal incidence. Localized plasmon polaritons are resonantly excited at 800 nm with 100 fs long pulses. The momentum distribution of emitted electrons reveals two distinct emission mechanisms: a coherent multiphoton photoemission process from the optically heated electron gas leads to an isotropic emission distribution...
October 26, 2017: Nano Letters
Yusong Zhang, Weikang Chen, Zhe Lin, Sheng Li, Thomas F George
For a conjugated polymer irradiated by two optical pulses, the whole process of excitation, involving lattice oscillations, oscillations of the energy level structure, and evolution of the electron cloud, is investigated. Localization of the electron cloud appears in the first 100 fs of irradiation, which in turn induces vibrations of lattice of the polymer chain as well as oscillations of the band gap. These oscillations filter the absorption of the external optical field inversely and convert the original optical field to an ultrafast light field whose intensity varies with a certain period...
August 21, 2017: Optics Express
Marinus Huber, Wolfgang Schweinberger, Fabian Stutzki, Jens Limpert, Ioachim Pupeza, Oleg Pronin
Excess relative intensity noise (RIN) constitutes one of the major limitations of most spectroscopic methods involving lasers. Here, we present an active RIN suppression scheme for a coherent mid-infrared (MIR) light source (8.4-11 µm), based on intra-pulse difference frequency generation (DFG). Three different stabilization concepts that rely on modulating the intensity of the driving near-infrared (NIR) pulse train with an acousto-optic modulator are investigated and compared. By using the wings of the NIR spectrum to generate the error signal, a RIN suppression of the MIR pulse train of up to a factor of 20 was achieved in the band between 1 Hz and 100 kHz, resulting in a total integrated RIN of 0...
September 18, 2017: Optics Express
Liang Mei, Peng Guan, Zheng Kong
Differential absorption lidar (DIAL) technique employed for remote sensing has been so far based on the sophisticated narrow-band pulsed laser sources, which require intensive maintenance during operation. In this work, a continuous-wave (CW) NO2 DIAL system based on the Scheimpflug principle has been developed by employing a compact high-power CW multimode 450 nm laser diode as the light source. Laser emissions at the on-line and off-line wavelengths of the NO2 absorption spectrum are implemented by tuning the injection current of the laser diode...
October 2, 2017: Optics Express
Frances Camille P Masim, Wei-Hung Hsu, Hao-Li Liu, Tetsu Yonezawa, Armandas Balčytis, Saulius Juodkazis, Koji Hatanaka
Photoacoustic signal enhancements were observed with a pair of time-delayed femtosecond pulses upon excitation of gold nanosphere colloidal suspension. A systematic experimental investigation of photoacoustic intensity within the delay time, Δt = 0 to 15 ns, was carried out. The results revealed a significant enhancement factor of ∼2 when the pre-pulse energy is 20-30% of the total energy. Pre-pulse and main pulse energy ratios, Ep(1):Es(2), were varied to determine the optimal ratio that yields to maximum photoacoustic signal enhancement...
August 7, 2017: Optics Express
Xiaolian Chen, Xinzhou Wu, Shuangshuang Shao, Jinyong Zhuang, Liming Xie, Shuhong Nie, Wenming Su, Zheng Chen, Zheng Cui
With the help of photonic sintering using intensive pulse light (IPL), copper has started to replace silver as a printable conductive material for printing electrodes in electronic circuits. However, to sinter copper ink, high energy IPL has to be used, which often causes electrode destruction, due to unreleased stress concentration and massive heat generated. In this study, a Cu/Sn hybrid ink has been developed by mixing Cu and Sn particles. The hybrid ink requires lower sintering energy than normal copper ink and has been successfully employed in a hybrid printing process to make metal-mesh transparent conductive films (TCFs)...
October 16, 2017: Scientific Reports
Lutful Ahad, Ismo Vartiainen, Tero Setälä, Ari T Friberg, Jari Turunen
We investigate the temporal coherence of random, pulsed, quasi-stationary scalar light fields and introduce a new type of expansion for the mutual coherence function in terms of fully coherent frequency-shifted quasi-monochromatic modes of identical shape. The mode representation is valid provided the pulse length is shorter and the coherence time is much shorter than the width of the time window in which the field is considered. The construction of the expansion is particularly straightforward since information is required only on the average spectrum and the average temporal intensity...
September 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
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