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Low-intensity pulsed laser

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https://www.readbyqxmd.com/read/28721044/stimulated-phase-shift-acoustic-nanodroplets-enhance-vancomycin-efficacy-against-methicillin-resistant-staphylococcus-aureus-biofilms
#1
Hao Guo, Ziming Wang, Quanyin Du, Pan Li, Zhigang Wang, Aimin Wang
PURPOSE: Bacterial biofilms on the surface of prostheses are becoming a rising concern in managing prosthetic joint infections. The inherent resistant features of biofilms render traditional antimicrobial therapy unproductive and revision surgery outcomes uncertain. This situation has prompted the exploration of novel antimicrobial strategies. The synergy of ultrasound microbubbles and vancomycin has been proposed as an efficient alternative for biofilm eradication. The purpose of this study was to evaluate the anti-biofilm effect of stimulated phase-shift acoustic nanodroplets (NDs) combined with vancomycin...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28720854/laser-pulse-shape-control-of-seeded-qed-cascades
#2
Matteo Tamburini, Antonino Di Piazza, Christoph H Keitel
QED cascades are complex avalanche processes of hard photon emission and electron-positron pair creation driven by ultrastrong electromagnetic fields. They play a fundamental role in astrophysical environments such as a pulsars' magnetosphere, rendering an earth-based implementation with intense lasers attractive. In the literature, QED cascades were also predicted to limit the attainable intensity in a set-up of colliding laser beams in a tenuous gas such as the residual gas of a vacuum chamber, therefore severely hindering experiments at extreme field intensities...
July 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28691773/visualization-of-aged-fingerprints-with-an-ultraviolet-laser
#3
Norimitsu Akiba, Kenro Kuroki, Kenji Kurosawa, Ken'ichi Tsuchiya
Detection of aged fingerprints is difficult because they can degrade over time with exposure to light, moisture, and temperature. In this study, aging fingerprints were visualized by time-resolved spectroscopy with an ultraviolet-pulsed laser. Fingerprints were prepared on glass slides and paper and then stored under three lighting conditions and two humidity conditions for up to a year. The fluorescence intensities of the fingerprints decreased with time. Samples were stored in the dark degraded less than in sunlight or under a fluorescent lamp...
July 10, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/28688752/comparison-of-effects-of-lllt-and-lipus-on-fracture-healing-in-animal-models-and-patients-a-systematic-review
#4
REVIEW
Mohammad Bayat, Amarjit Virdi, Reza Jalalifirouzkouhi, Fatemehalsadat Rezaei
The aim of this paper is to study the in vivo potency of low-level laser therapy (LLLT) and low intensity pulsed ultrasound (LIPUS) alone, accompanied by bone grafts, or accompanied by other factors on fracture healing in animal models and patients. In this paper, we aim to systematically review the published scientific literature regarding the use of LLLT and LIPUS to accelerate fracture healing in animal models and patients. We searched the PubMed database for the terms LLLT or LIPUS and/or bone, and fracture...
July 5, 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/28653018/outrunning-damage-electrons-vs-x-rays-timescales-and-mechanisms
#5
John C H Spence
Toward the end of his career, Zewail developed strong interest in fast electron spectroscopy and imaging, a field to which he made important contributions toward his aim of making molecular movies free of radiation damage. We therefore compare here the atomistic mechanisms leading to destruction of protein samples in diffract-and-destroy experiments for the cases of high-energy electron beam irradiation and X-ray laser pulses. The damage processes and their time-scales are compared and relevant elastic, inelastic, and photoelectron cross sections are given...
July 2017: Structural Dynamics (Melville, N.Y.)
https://www.readbyqxmd.com/read/28652897/low-level-laser-therapy-in-russia-history-science-and-practice
#6
REVIEW
Sergey Vladimirovich Moskvin
In Russia (formerly USSR) study of biomodulation action (BMA) mechanisms of low-intensity laser irradiation (LILI) began in 1964, immediately after the development of lasers. During the period from 1965 to 1972 several dozens of scientific conferences were held, hundreds of studies were published. Generally, secondary mechanisms and results of LILI effect on patients with various diseases were studied. This data was immediately implemented into practical medicine in the fields of oncology, surgery, dermatology and dentistry, and since 1974 low level laser therapy (LLLT) is included in the standard of state medical care...
2017: Journal of Lasers in Medical Sciences
https://www.readbyqxmd.com/read/28609301/a-light-weight-compact-proton-gantry-design-with-a-novel-dose-delivery-system-for-broad-energetic-laser-accelerated-beams
#7
U Masood, T E Cowan, W Enghardt, K M Hofmann, L Karsch, F Kroll, U Schramm, J J Wilkens, J Pawelke
Proton beams may provide superior dose-conformity in radiation therapy. However, the large sizes and costs limit the widespread use of proton therapy (PT). The recent progress in proton acceleration via high-power laser systems has made it a compelling alternative to conventional accelerators, as it could potentially reduce the overall size and cost of the PT facilities. However, the laser-accelerated beams exhibit different characteristics than conventionally accelerated beams, i.e. very intense proton bunches with large divergences and broad-energy spectra...
July 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28546559/mapping-few-femtosecond-slices-of-ultra-relativistic-electron-bunches
#8
Tim Plath, Christoph Lechner, Velizar Miltchev, Philipp Amstutz, Nagitha Ekanayake, Leslie Lamberto Lazzarino, Theophilos Maltezopoulos, Jörn Bödewadt, Tim Laarmann, Jörg Roßbach
Free-electron lasers are unique sources of intense and ultra-short x-ray pulses that led to major scientific breakthroughs across disciplines from matter to materials and life sciences. The essential element of these devices are micrometer-sized electron bunches with high peak currents, low energy spread, and low emittance. Advanced FEL concepts such as seeded amplifiers rely on the capability of analyzing and controlling the electron beam properties with few-femtosecond time resolution. One major challenge is to extract tomographic slice parameters instead of projected electron beam properties...
May 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28545054/an-optimized-small-animal-tumour-model-for-experimentation-with-low-energy-protons
#9
Elke Beyreuther, Kerstin Brüchner, Mechthild Krause, Margret Schmidt, Rita Szabo, Jörg Pawelke
BACKGROUND: The long-term aim of developing laser based particle acceleration towards clinical application requires not only substantial technological progress, but also the radiobiological characterization of the resulting ultra-short and ultra-intensive particle beam pulses. After comprehensive cell studies a mouse ear tumour model was established allowing for the penetration of low energy protons (~20 MeV) currently available at laser driven accelerators. The model was successfully applied for a first tumour growth delay study with laser driven electrons, whereby the need of improvements crop out...
2017: PloS One
https://www.readbyqxmd.com/read/28508042/toward-continuous-wave-operation-of-organic-semiconductor-lasers
#10
Atula S D Sandanayaka, Toshinori Matsushima, Fatima Bencheikh, Kou Yoshida, Munetomo Inoue, Takashi Fujihara, Kenichi Goushi, Jean-Charles Ribierre, Chihaya Adachi
The demonstration of continuous-wave lasing from organic semiconductor films is highly desirable for practical applications in the areas of spectroscopy, data communication, and sensing, but it still remains a challenging objective. We report low-threshold surface-emitting organic distributed feedback lasers operating in the quasi-continuous-wave regime at 80 MHz as well as under long-pulse photoexcitation of 30 ms. This outstanding performance was achieved using an organic semiconductor thin film with high optical gain, high photoluminescence quantum yield, and no triplet absorption losses at the lasing wavelength combined with a mixed-order distributed feedback grating to achieve a low lasing threshold...
April 2017: Science Advances
https://www.readbyqxmd.com/read/28492049/a-review-of-laser-and-light-therapy-in-melasma
#11
REVIEW
M K Trivedi, F C Yang, B K Cho
Melasma is a dysregulation of the homeostatic mechanisms that control skin pigmentation and excess pigment is produced. Traditional treatment approaches with topical medications and chemical peels are commonly used but due to the refractory and recurrent nature of melasma, patients often seek alternative treatment strategies such as laser and light therapy. Several types of laser and light therapy have been studied in the treatment of melasma. Intense pulsed light, low fluence Q-switched lasers, and non-ablative fractionated lasers are the most common lasers and light treatments that are currently performed...
March 2017: International Journal of Women's Dermatology
https://www.readbyqxmd.com/read/28485872/new-lasers-and-light-sources-old-and-new-risks
#12
REVIEW
Uwe Paasch, Antje Schwandt, Nikolaus Seeber, Gerd Kautz, Sonja Grunewald, Merete Haedersdal
Recent developments (new wavelengths, treatment concepts, and combinations) in the field of lasers, intense pulsed light (IPL), LED, as well as new energy and light sources have opened up new therapeutic options that extend beyond mere aesthetic indications. Thus, while fractional lasers used to be employed to merely treat wrinkles, the same devices - in the context of laser-assisted drug delivery - have now become important tools in the treatment of scars, field cancerization, and epithelial tumors. The requirements posed to physicians, both with respect to establishing the indication and conducting treatment, have been growing along with the increase in technological complexity as well as the rising number of comorbidities and comedications in a patient population that continues to age...
May 2017: Journal der Deutschen Dermatologischen Gesellschaft, Journal of the German Society of Dermatology: JDDG
https://www.readbyqxmd.com/read/28474903/reduction-of-intrinsic-electron-emittance-from-photocathodes-using-ordered-crystalline-surfaces
#13
Siddharth Karkare, Jun Feng, Xumin Chen, Weishi Wan, F Javier Palomares, T-C Chiang, Howard A Padmore
The generation of intense electron beams with low emittance is key to both the production of coherent x rays from free electron lasers, and electron pulses with large transverse coherence length used in ultrafast electron diffraction. These beams are generated today by photoemission from disordered polycrystalline surfaces. We show that the use of single crystal surfaces with appropriate electronic structures allows us to effectively utilize the physics of photoemission to generate highly directed electron emission, thus reducing the emittance of the electron beam being generated...
April 21, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28463283/high-resolution-flash-three-dimensional-lidar-systems-based-on-polarization-modulation
#14
Peng Zhang, Xiaoping Du, Jiguang Zhao, Yishuo Song, Hang Chen
Two high resolution flash LIDAR systems based on polarization modulation are demonstrated in this paper. One utilizes a polarization beam splitter (PBS) and two charge coupled device (CCD) arrays; the other utilizes a micro-polarizer array and a CCD array. Compared with the traditional flash LIDAR systems, the main advantage of the presented flash LIDAR systems is replacing high bandwidth detectors with a polarization modulator and low bandwidth detectors. The polarization modulator is used to modulate the polarization state of the received laser pulse in time and the range information can be mapped into the intensity received by the low bandwidth detectors...
May 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/28456263/note-energy-calibration-of-a-femtosecond-photoelectron-imaging-detector-with-correction-for-the-ponderomotive-shift-of-atomic-ionization-energies
#15
O Hüter, F Temps
Femtosecond photoelectron imaging spectroscopy is a powerful technique for following state-resolved molecular transformations in complex coupled potential energy landscapes. To avoid unwanted nonlinear side-effects, the employed laser pulse energies are usually reduced to minimal values. However, the energy calibration of the photoelectron imaging detector is ideally performed using multi-photon above-threshold ionization of suitable atomic species, for which rather high laser intensities are required. In this work, we show that the calibration spectra of xenon obtained with high laser pulse energies cannot be directly used for the evaluation of molecular photoelectron spectra recorded using low-energy laser pulses...
April 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28438002/hot-luminescence-from-gold-nanoflowers-and-its-application-in-high-density-optical-data-storage
#16
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/28428549/low-noise-time-resolved-optical-sensing-of-electromagnetic-pulses-from-petawatt-laser-matter-interactions
#17
T S Robinson, F Consoli, S Giltrap, S J Eardley, G S Hicks, E J Ditter, O Ettlinger, N H Stuart, M Notley, R De Angelis, Z Najmudin, R A Smith
We report on the development and deployment of an optical diagnostic for single-shot measurement of the electric-field components of electromagnetic pulses from high-intensity laser-matter interactions in a high-noise environment. The electro-optic Pockels effect in KDP crystals was used to measure transient electric fields using a geometry easily modifiable for magnetic field detection via Faraday rotation. Using dielectric sensors and an optical fibre-based readout ensures minimal field perturbations compared to conductive probes and greatly limits unwanted electrical pickup between probe and recording system...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28427634/enhanced-porosity-and-permeability-of-three-dimensional-alginate-scaffolds-via-acoustic-microstreaming-induced-by-low-intensity-pulsed-ultrasound
#18
Gepu Guo, Yong Ma, Yang Guo, Chunbing Zhang, Xiasheng Guo, Juan Tu, Alfred C H Yu, Junru Wu, Dong Zhang
The shear stress resulting from the microstreaming induced by low-intensity pulsed ultrasound (LIPUS) has been often used to improve the permeability of cell membrane or porous engineering scaffolds. In the present study, three-dimensional (3-D) scaffold culture systems were constituted to simulate the in vivo microenvironment, providing benefits for cell growth. In order to investigate the mechanism underlying the enhanced porosity and permeability of the 3-D alginate scaffolds by using LIPUS with varied acoustic intensities, two quantitative imaging techniques (i...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28414231/organic-phosphorescence-nanowire-lasers
#19
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/28383017/room-temperature-subnanosecond-waveguide-lasers-in-nd-yvo4-q-switched-by-phase-change-vo2-a-comparison-with-2d-materials
#20
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
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