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https://www.readbyqxmd.com/read/28418076/ultrasonic-modulation-of-tissue-optical-properties-in-ex-vivo-porcine-skin-to-improve-transmitted-transdermal-laser-intensity
#1
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
#2
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
#3
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 low quantum yield of phosphorescence (ΦP). Here, we reported the first triplet-phosphorescence OSSL from nanowire microcavity of a sulfide-substituted difluoroboron compound...
April 17, 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
#4
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
#5
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
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
https://www.readbyqxmd.com/read/28345856/instantaneous-pulsed-light-cross-linking-of-a-polymer-gate-dielectric-for-flexible-organic-thin-film-transistors
#17
Soo Jin Kim, Mi Jang, Hee Yeon Yang, Jinhan Cho, Ho Sun Lim, Hoichang Yang, Jung Ah Lim
We report the instantaneous pulsed-light cross-linking of polymer gate dielectrics on a flexible substrate by using intensely pulsed white light (IPWL) irradiation. Irradiation with IPWL for only 1.8 s of a poly(4-vinylphenol) (PVP) thin film with the cross-linking agent poly(melamine-co-formaldehyde) (PMF) deposited on a plastic substrate was found to yield fully cross-linked PVP films. It was confirmed that the IPWL-cross-linked PVP films have smooth pinhole-free surfaces and exhibit a low leakage current density, organic solvent resistance, and good compatibility with organic semiconductor, and that they can be used as replacements for typical PVP dielectrics that are cross-linked with time and energy intensive thermal heating processes...
March 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28341262/pulsed-xenon-ultraviolet-light-disinfection-in-a-burn-unit-impact-on-environmental-bioburden-multidrug-resistant-organism-acquisition-and-healthcare-associated-infections
#18
Caroline Green, Jeremy C Pamplin, Kristine N Chafin, Clinton K Murray, Heather C Yun
Portable pulsed xenon ultraviolet disinfection (PPX-UVD) may reduce healthcare associated infections (HAI). There is limited data to inform use in burn intensive care units (BICU), where multidrug-resistant organisms (MDRO), especially gram negative rods (GNR), commonly cause disease. We evaluated PPX-UVD effects on environmental bioburden and rates of HAI and MDRO acquisition in a BICU. PPX-UVD was used for 3 months after standard cleaning of patient and operating rooms (ORs). Settle and touch plates in patient rooms and ORs were obtained after standard cleaning, pre-and post-PPX-UVD...
March 2017: Burns: Journal of the International Society for Burn Injuries
https://www.readbyqxmd.com/read/28338214/light-therapies-for-acne-abridged-cochrane-systematic-review-including-grade-assessments
#19
REVIEW
J Barbaric, R Abbott, P Posadzki, M Car, L H Gunn, A M Layton, A Majeed, J Car
We undertook a Cochrane review of randomized controlled trials (RCTs) evaluating the effects of light-based interventions for acne vulgaris. We searched the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, ISI Web of Science, and grey literature sources (September 2015). We used the Grading of Recommendations Assessment, Development and Evaluation Working Group approach to assess the quality of evidence (QE). We included 71 RCTs (4211 participants, median sample size 31). Results from a single study (n = 266, low QE) showed little or no difference in effectiveness on participants' assessment of improvement between 20% aminolevulinic acid (ALA) photodynamic therapy (PDT), activated by blue light, versus vehicle plus blue light, whereas another study (n = 180) of a comparison of ALA-PDT (red light) concentrations showed 20% ALA-PDT was no more effective than 15%, but better than 10% and 5% ALA-PDT...
March 24, 2017: British Journal of Dermatology
https://www.readbyqxmd.com/read/28315815/self-assembled-photoadditives-in-polyester-films-allow-stop-and-go-chemical-release
#20
Ting Cheng, Richard O'Rorke, Raphael Francois Ortiz, Tay Yee Yan, Eva Hemmer, Fiorenzo Vetrone, Robert S Marks, Terry W J Steele
Near-infrared (NIR) triggered chemical delivery allows on-demand release with the advantage of external tissue stimulation. Bioresorbable polyester poly-l-lactic acid (PLLA) was compounded with photoadditives of neat zinc oxide (ZnO) nanoparticles and 980→365nm LiYF4:Tm(3+), Yb(3+) upconverting nanoparticles (UCNP). Subsequently, neat ZnO and UCNP blended PLLA films of sub-50μm thickness were knife casted with a hydrophobic small molecule drug mimic, fluorescein diacetate. The PLLA films displayed a 500 times increase in fluorescein diacetate release from the 50mW NIR irradiated PLLA/photoadditive film compared to non-irradiated PLLA control films...
March 16, 2017: Acta Biomaterialia
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