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Pulsed light

José Carlos Tatmatsu-Rocha, Carla Roberta Tim, Lucimar Avo, Rubens Bernardes-Filho, Patricia Brassolatti, Hueliton Wilian Kido, Michael R Hamblin, Nivaldo Antonio Parizotto
OBJECTIVE: Mitochondrial dysfunction has been associated with the development of diabetes mellitus which is characterized by disorders of collagen production and impaired wound healing. This study analyzed the effects of photobiomodulation (PBM) mediated by laser and light-emitting diode (LED) on the production and organization of collagen fibers in an excisional wound in an animal model of diabetes, and the correlation with inflammation and mitochondrial dynamics. METHODS: Twenty Wistar rats were randomized into 4 groups of 5 animals...
August 3, 2018: Journal of Photochemistry and Photobiology. B, Biology
Do-Kyun Kim, Dong-Hyun Kang
UVC light, a strong surface disinfection technology, is used world-wide to ensure not only environmental safety, but also food safety. Several drawbacks associated with usage of mercury-containing UV lamps, especially, human and environmental health risks, led to the Minamata convention which prohibits manufacturing and import/export of products containing mercury. Therefore, LED-based UVC irradiation, a new technology which is eco-friendly and an effective UV emitting source, has been researched recently. However, to date, there has been no report describing pulsed UVC-LED for improving inactivation of foodborne pathogens, although much research regarding conventional pulsed xenon lamps has been published...
August 10, 2018: Applied and Environmental Microbiology
Alisson Alves da Silva, Gustavo Graciano Fonseca
Growth studies are important to increase the knowledge about the physiology of microalgae. The development of suitable culture media allows optimum growth to each species. The genus Chlorella has the ability to adapt to various environmental and nutritional conditions. Thus, the aim of this work was to evaluate the physiology of Chlorella sorokiniana CTT 7727 at different growth conditions with Basal Bold (BB) medium. For that, heterotrophic, autotrophic and mixotrophic cultures were carried out. The maximum specific growth rates (µmax ), the maximum biomass concentrations (Xmax ) and cell productivities (PX ) were calculated for each experiment...
August 9, 2018: Environmental Technology
J Matthew Knight, Gerd Kautz
BACKGROUND: While skin aging is triggered by multiple factors and typically presents with multiple manifestations, conventional treatment regimens deploy a single treatment modality. Typical approaches exploit ablative techniques, which involve considerable patient discomfort and downtime and can induce adverse events. Non-ablative fractionated laser (NAFL) resurfacing promotes neocollagenesis, with significantly fewer complications and discomfort. At the same time, intense pulsed light (IPL) therapies have a marked impact on skin tone, with an effect on collagen deposition...
August 8, 2018: Lasers in Surgery and Medicine
Xueming Liu, Xiankun Yao, Yudong Cui
Real-time spectroscopy access to ultrafast fiber lasers opens new opportunities for exploring complex soliton interaction dynamics. Here, we have reported the first observation, to the best of our knowledge, of the entire buildup process of soliton molecules (SMs) in a mode-locked laser. We have observed that the birth dynamics of a stable SM experiences five different stages, i.e., the raised relaxation oscillation (RO) stage, beating dynamics stage, transient single pulse stage, transient bound state, and finally the stable bound state...
July 13, 2018: Physical Review Letters
Sarojini Jeeva Panchu, Shanel Dhani, Anil Chuturgoon, Mathew K Moodley
Here in, we report the investigation of the immunotoxicity of gold nanoparticles decorated on inorganic fullerene like MoS2 nanostructure (IFMoS2 - AuNPs) on the THP-1 immune cell line. The MoS2 nanoparticle with fullerene like nanostructure (IFMoS2 ) was synthesized by double pulsed laser-assisted chemical vapour deposition (LCVD) method from bulk MoS2 at the temperature of 700 °C. The MoS2 inorganic fullerene-like nanoparticles grown by vapour-solid process (VS). The surface of the IFMoS2 was decorated with gold nanoparticles (AuNPs) to develop the semiconductor biocompatibility interface...
August 1, 2018: Journal of Photochemistry and Photobiology. B, Biology
Tanawan Soimala, Antina Lübke-Becker, Stefan Schwarz, Andrea T Feßler, Charlotte Huber, Torsten Semmler, Roswitha Merle, Heidrun Gehlen, Johanna C Eule, Birgit Walther
Severe infections due to methicillin-resistant Staphylococcus aureus (MRSA) have been increasingly recognized in virtually all fields of veterinary medicine. Our objective was to study the occurrence, phylogenetic relationships and antimicrobial resistance properties of MRSA isolated from ocular surfaces of horses prior to invasive procedures. Within a 49-week sampling period, ocular swabs obtained from 46 eyes of 44 horses, including eyes with clinical signs of conjunctivitis/blepharitis, keratitis or uveitis were screened for the presence of S...
August 2018: Veterinary Microbiology
Farid Atry, Rex Chin-Hao Chen, Jane Pisaniello, Sarah Brodnick, Aaron Suminski, Joseph Novello, Jared Ness, Justin Williams, Ramin Pashaie
We introduce an engineering approach to study spatiotemporal correlations between vasodynamics and the nearby neural activity in open-loop and closed-loop paradigms. 
 Approach: We integrated optogenetic technology with optical coherence tomography to apply spatiotemporal patterns of optical neurostimulation to the cortex of transgenic optogenetic mice and measure blood flow-rate, velocity, and diameter changes of selected middle cerebral artery branches.
 Main results: The spatiotemporal characteristics of blood flow-rate, velocity, and vessel diameter responses to localized neurostimulation light pulses were measured...
August 6, 2018: Journal of Neural Engineering
A Cantaluppi, M Buzzi, G Jotzu, D Nicoletti, M Mitrano, D Pontiroli, M Riccò, A Perucchi, P Di Pietro, A Cavalleri
Optical excitation at terahertz frequencies has emerged as an effective means to dynamically manipulate complex materials. In the molecular solid K3 C60 , short mid-infrared pulses transform the high-temperature metal into a non-equilibrium state with the optical properties of a superconductor. Here we tune this effect with hydrostatic pressure and find that the superconducting-like features gradually disappear at around 0.3 GPa. Reduction with pressure underscores the similarity with the equilibrium superconducting phase of K3 C60 , in which a larger electronic bandwidth induced by pressure is also detrimental for pairing...
August 2018: Nature Physics
Mary Matthews, Felipe Morales, Alexander Patas, Albrecht Lindinger, Julien Gateau, Nicolas Berti, Sylvain Hermelin, Jerome Kasparian, Maria Richter, Timm Bredtmann, Olga Smirnova, Jean-Pierre Wolf, Misha Ivanov
Light can be used to modify and control properties of media, as in the case of electromagnetically induced transparency or, more recently, for the generation of slow light or bright coherent XUV and X-ray radiation. Particularly unusual states of matter can be created by light fields with strengths comparable to the Coulomb field that binds valence electrons in atoms, leading to nearly-free electrons oscillating in the laser field and yet still loosely bound to the core [1,2]. These are known as Kramers-Henneberger states [3], a specific example of laser-dressed states [2]...
July 2018: Nature Physics
Xin Mu, Li Wang, Lijuan Wang, Rui Ge, Haiqiang Dang, Kuanhou Mou
BACKGROUND/PURPOSE: Basal cell carcinoma (BCC) often occurs in the face of middle and old aged people. Given its particular location, aminolevulinic acid-photodynamic therapy (ALA-PDT) is often applied in cosmetology and inappropriate surgical treatment. Specific measures in PDT treatment should be performed to increase the ALA penetration capability because of the limited depth of ALA penetration. This research aims to explore the method that facilitates ALA penetration. METHODS: Three patients with BCC were subjected to four regular sessions of ALA-PDT every other week...
August 2, 2018: Photodiagnosis and Photodynamic Therapy
Diao Li, Hui Xue, Yadong Wang, Mei Qi, Wonjae Kim, Changfeng Li, Juha Riikonen, Zhaoyu Ren, Jintao Bai, Harri Lipsanen, Zhipei Sun
We report the synchronization of two actively Q -switched fiber lasers operating at 1.5 μm and 2 μm with a shared broadband graphene electro-optic modulator. Two graphene monolayer sheets separated with a high- k HfO 2 dielectric layer are configured to enable broadband light modulation. The graphene electro-optic modulator is shared by two optical fiber laser cavities (i.e., an erbium-doped fiber laser cavity and a thulium/holmium-codoped fiber laser cavity) to actively Q -switch the two lasers, resulting in stable synchronized pulses at 1...
August 1, 2018: Optics Letters
Bingjie Zhou, Jingui Ma, Jing Wang, Peng Yuan, Guoqiang Xie, Liejia Qian
Slow and fast light are ubiquitous in optical amplifiers. In this Letter, we show for the first time, to the best of our knowledge, that optical parametric amplification (OPA) in chirped quasi-phase-matching structures can act as a platform for group-velocity control in the femtosecond regime. The resonant cascaded nonlinear phase underlies the group-velocity control, which manifests an unusual effect that both slow and fast light can be achieved under the normal condition of signal amplification. As numerically demonstrated in the OPA based on the lithium niobate crystal, the signal and idler pulse can be significantly delayed in time comparable to the signal duration and can also keep high fidelity for durations down to 100 fs until the crystal dispersion becomes effective...
August 1, 2018: Optics Letters
M Zukerstein, M Kozák, F Trojánek, P Malý
We report on a simple approach for the compression of few-cycle laser pulses generated in an ultrafast laser oscillator to a duration corresponding to 1.7 cycles of near-infrared light (compression factor of 1.44) by nonlinear spectral broadening in diamond and subsequent dispersion compensation using chirped mirrors. After the spectral broadening, the pulse spectrum spans over almost an octave (580-1000 nm at the -10  dB level). The pulses are compressed by broadband-chirped mirrors and a wedge pair to a duration of 4...
August 1, 2018: Optics Letters
Kevin Thomas, Callum George Brownstein, Jack Dent, Paul Parker, Stuart Goodall, Glyn Howatson
PURPOSE: Training methods that require maximal intensity efforts against light- and heavy-resistance are commonly used for athletic development. Typically these sessions are separated by at least 48 hours recovery on the assumption that such efforts elicit marked fatigue of the central nervous system (CNS), but this posit has not been well-studied. The aim of the study was to assess the aetiology and recovery of fatigue after heavy-resistance (strength), jump, and sprint training methods...
July 31, 2018: Medicine and Science in Sports and Exercise
Michael Semmlinger, Ming Lun Tseng, Jian Yang, Ming Zhang, Chao Zhang, Wei-Yi Tsai, Din Ping Tsai, Peter Nordlander, Naomi J Halas
Vacuum ultraviolet (VUV) light has important applications in many fields, ranging from device fabrication to photochemistry, from environmental remediation to microscopy and spectroscopy. Methods to produce coherent VUV light frequently utilize high harmonic generation in media such as rare gases or atomic vapors; nonlinear optical crystals that support second harmonic generation into the VUV are quite rare. Here, we demonstrate an all-dielectric metasurface designed for the nonlinear optical generation of VUV light...
August 1, 2018: Nano Letters
David Kingsley, Robinson Kuis, Rafael Perez, Isaac Basaldua, Paul Burkins, Aristides Marcano, Anthony Johnson
BACKGROUND: Previous work indicated that an ultrashort pulse (USP) 425 nm laser is capable of inactivating murine norovirus (MNV: Virol. J. 11:20), perhaps via an impulsive stimulated Raman scattering (ISRS) mechanism, and does not substantially damage human plasma proteins (PLOS One 9:11). Here, further investigation of virus inactivation by laser light is performed. METHODS: In this study, we evaluate whether inactivation of MNV is specific to the USP wavelength of 425 nm, or if it occurs at other visible wavelengths, using a tunable mode-locked Ti-Sapphire laser that has been frequency doubled to generate femtosecond pulses at wavelengths of 400, 408, 425, 450, 465, and 510 nm...
July 31, 2018: Virology Journal
Przemysław Wachulak, Martin Duda, Tomasz Fok, Andrzej Bartnik, Zhanshan Wang, Qiushi Huang, Antoni Sarzyński, Alexandr Jancarek, Henryk Fiedorowicz
We present a proof of principle experiment on single-shot near edge soft X-ray fine structure (NEXAFS) spectroscopy with the use of a laboratory laser-plasma light source. The source is based on a plasma created as a result of the interaction of a nanosecond laser pulse with a double stream gas puff target. The laser-plasma source was optimized for efficient soft X-ray (SXR) emission from the krypton/helium target in the wavelength range from 2 nm to 5 nm. This emission was used to acquire simultaneously emission and absorption spectra of soft X-ray light from the source and from the investigated sample using a grazing incidence grating spectrometer...
July 28, 2018: Materials
R B Versteeg, J Zhu, P Padmanabhan, C Boguschewski, R German, M Goedecke, P Becker, P H M van Loosdrecht
We present a flexible and efficient ultrafast time-resolved spontaneous Raman spectroscopy setup to study collective excitation and quasi-particle dynamics in quantum materials. The setup has a broad energy tuning range extending from the visible to near infrared spectral regions for both the pump excitation and Raman probe pulses. Additionally, the balance between energy and time-resolution can be controlled. A high light collecting efficiency is realized by high numerical aperture collection optics and a high-throughput flexible spectrometer...
July 2018: Structural Dynamics (Melville, N.Y.)
Kim Minhee, Young-Gun Park, Seungbum Kang, Young Jung Roh
PURPOSE: The purpose of this study is to evaluate the retinal tissue response upon selective retina therapy (SRT) with or without real-time feedback-controlled dosimetry (RFD) in rabbits. METHODS: Eighteen eyes of nine Chinchilla Bastard rabbits were treated by SRT with or without RFD (Q-switched Nd:YLF, wavelength 527 nm, pulse duration 1.7 μs). RFD operated by optoacoustic and reflectometric methods detects the microbubbles from retinal pigment epithelium (RPE) damage in real time...
July 28, 2018: Graefe's Archive for Clinical and Experimental Ophthalmology
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