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Pulsed light

Mikaël Ghadimi Nassiri, Etienne Brasselet
We report on a programmable liquid crystal spatial light modulator enabling independent orbital angular momentum state control on multiple spectral channels. This is done by using electrically controllable "topological pixels" that independently behave as geometric phase micro-optical elements relying on self-engineered liquid crystal defects. These results open interesting opportunities in optical manipulation, sensing, imaging, and communications, as well as information processing. In particular, spectral vortex modulation allows considering singular spatiotemporal shaping of ultrashort pulses which may find applications in many areas such as material processing, spectroscopy, or elementary particles acceleration...
November 23, 2018: Physical Review Letters
Kenta Abe, Hiromu Yawo
Loss of one sensory modality can cause other types to become more perceptive (cross-modal plasticity). To test the hypothesis that the loss of vision changes the perceptual threshold in the somatosensory system, we applied optogenetics to directly manipulate the afferent inputs involved in the whisker-barrel system using a transgenic rat (W-TChR2V4) that expresses channelrhodopsin-2 (ChR2) selectively in the large mechanoreceptive neurons in the trigeminal ganglion (TG) and their peripheral nerve terminals...
2018: PloS One
Felix Schottroff, Antje Fröhling, Marija Zunabovic-Pichler, Anna Krottenthaler, Oliver Schlüter, Henry Jäger
The viable but non-culturable (VBNC) state, as well as sublethal injury of microorganisms pose a distinct threat to food safety, as the use of traditional, culture-based microbiological analyses might lead to an underestimation or a misinterpretation of the product's microbial status and recovery phenomena of microorganisms may occur. For thermal treatments, a large amount of data and experience is available and processes are designed accordingly. In case of innovative inactivation treatments, however, there are still several open points with relevance for the investigation of inactivation mechanisms as well as for the application and validation of the preservation processes...
2018: Frontiers in Microbiology
(no author information available yet)
No abstract text is available yet for this article.
December 2018: Nature
Emine Esra Karaca, Özlem Evren Kemer, Dilay Özek
PURPOSE: To assess the effect of intense regulated pulse light (E-Eye; E-Swin, France) on the treatment of meibomian gland dysfunction. SETTING: Health Sciences University, Ankara Numune Training and Research Hospital, Department of Ophthalmology. METHODS: A total of 26 patients underwent intense pulsed light treatment (E-Eye; E-Swin), with homogeneously sequenced five light pulses delivered to one eye at 1, 15, and 45 days following baseline evaluation...
December 4, 2018: European Journal of Ophthalmology
Radius Bhayu Prasetiyo, Kyu-Sang Choi, Gi-Hun Yang
In this work, an algorithm was developed to measure respiration rate for an embedded device that can be used by a field robot for relief operations. With this algorithm, the rate measurement was calculated based on direct influences of respiratory-induced intensity variation (RIIV) on blood flow in cardiovascular pathways. For this, a photoplethysmogram (PPG) sensor was used to determine changes in heartbeat frequencies. The PPG sensor readings were filtered using an Information Filter and a fast Fourier transform (FFT) to determine the state of RIIV...
November 30, 2018: Sensors
Gunzung Kim, Yongwan Park
In the coded pulse scanning light detection and ranging (LIDAR) system, the number of laser pulses used at a given measurement point changes depending on the modulation and the method of spreading used in optical code-division multiple access (OCDMA). The number of laser pulses determines the pulse width, output power, and duration of the pulse transmission of a measurement point. These parameters determine the maximum measurement distance of the LIDAR and the number of measurement points that can be employed per second...
November 30, 2018: Sensors
Arif Kivanc Ustun, Jun Zou
In this paper, we report a new photoacoustic sensing probe design consisting of two optical fibers. One optical fiber is used for delivering the excitation light pulses. The other one serves as an acoustic delay line to relay the generated PA signal from the target to an outside ultrasound transducer. With the addition of suitable time delay, the original PA signal can be easily separated from the interference signals. To demonstrate this new design, a prototype probe was designed, fabricated and tested. The PA sensing performance was characterized with different concentration of black and red dye solutions...
March 2019: Photoacoustics
Krishna P Dhakal, Hyunmin Kim, Seonwoo Lee, Youngjae Kim, JaeDong Lee, Jong-Hyun Ahn
Here, we investigate the ultrafast carrier dynamics and electronic states of exfoliated ReS2 films using time-resolved second harmonic generation (TSHG) microscopy and density functional theory (DFT) calculations. The second harmonic generation (SHG) of layers with various thicknesses is probed using a 1.19-eV beam. Up to ~13 nm, a gradual increment is observed, followed by a decrease caused by bulk interferometric light absorption. The addition of a pump pulse tuned to the exciton band gap (1.57 eV) creates a decay-to-rise TSHG profile as a function of the probe delay...
2018: Light, Science & Applications
Christian Gaida, Martin Gebhardt, Tobias Heuermann, Fabian Stutzki, Cesar Jauregui, Jose Antonio-Lopez, Axel Schülzgen, Rodrigo Amezcua-Correa, Andreas Tünnermann, Ioachim Pupeza, Jens Limpert
The development of high-power, broadband sources of coherent mid-infrared radiation is currently the subject of intense research that is driven by a substantial number of existing and continuously emerging applications in medical diagnostics, spectroscopy, microscopy, and fundamental science. One of the major, long-standing challenges in improving the performance of these applications has been the construction of compact, broadband mid-infrared radiation sources, which unify the properties of high brightness and spatial and temporal coherence...
2018: Light, Science & Applications
Chang-Ha Lee, Jack Ferracane, In-Bog Lee
OBJECTIVES: The purpose of this study was to investigate the effects of radiant emittance and cure time of pulse width modulation (PWM)-controlled LED light on polymerization shrinkage/stress kinetics and surface hardness of dental composites. METHODS: A conventional (Filtek Z250) and a bulk-fill (Filtek Bulk Fill Posterior; BFP) composite were investigated. The duty ratio (% of time the light is on) and cure time of the LED light were controlled using an Arduino UNO microcontroller (PWM) as follows: 10%/100s, 20%/50s, 30%/33...
December 2018: Dental Materials: Official Publication of the Academy of Dental Materials
X J Yu, C Z Diao, T Venkatesan, M B H Breese, A Rusydi
A new beamline and a six-circle UHV diffractometer have been constructed at the Singapore Synchrotron Light Source with a broad energy coverage from 3.5 to 1500 eV. The beamline is optimized for ultraviolet-vacuum-ultraviolet optical reflectivity and resonant soft X-ray scattering with medium energy resolution over a broad energy range, achieved by using a self-focusing monochromator consisting of a plane mirror and three variable line spacing gratings. The unique character of the diffractometer comprises 4-circles in the vertical plane and 2-circles in the horizontal plane...
November 2018: Review of Scientific Instruments
Vic Narurkar
Bruising after dermal filler and neuromodulator injections is a common side effect and can have durations of 1 to 2 weeks. While it ultimately resolves, faster resolution can produce better outcomes for patients and also make patients more likely to return for future treatments. We report the successful reduction in bruising following injections of fillers with an intense pulsed light source. We also documented the onset of action of bruising resolution with serial photographs. Resolution started within the first hour of treatment and continued rapidly over 48 hours...
November 1, 2018: Journal of Drugs in Dermatology: JDD
E V Askhadulin, T V Konchugova, S V Moskvin
AIM: The objective of the present study was the evaluation of the effectiveness of the combined treatment of the patients presenting with trophic ulcers associated with chronic venous insufficiency of the lower extremities of venous etiology with the application of low-intensity laser therapy (LILT) at different wavelengths. MATERIAL AND METHODS: The study included the patients presenting with chronic venous insufficiency (CVI) (class C6 in accordance with the CEAP clinical classification)...
2018: Voprosy Kurortologii, Fizioterapii, i Lechebnoĭ Fizicheskoĭ Kultury
Sophie A L Schacht, Patricia Stahn, Marius Hinsberger, Bernhard Schick, Gentiana I Wenzel
The tympanic membrane (TM) separates the outer ear from the tympanic cavity. Repeated pathologies can permanently decrease its tension, inducing conductive hearing loss and adhesive processes up to cholesteatoma. The current main therapy is its surgical reconstruction. Even though lasers have been proposed to tighten atrophic TMs, details of this effect, specifically histological analyses, are missing. We therefore used laser pulses to induce TM collagen remodeling in an animal model to compare the histological and electrophysiological effects of different applied laser intensities before entering clinical studies...
November 2018: Journal of Biomedical Optics
Qiangbing Guo, Zhipeng Qin, Zhuan Wang, Yu-Xiang Weng, Xiaofeng Liu, Guoqiang Xie, Jianrong Qiu
Plasmons in conducting nanostructures offer the means to efficiently manipulate light at the nanoscale with subpicosecond speed in an all-optical operation fashion, thus allowing for constructing high performance all-optical signal-processing devices. Here, by exploiting the ultrafast nonlinear optical properties of broadly tunable mid-infrared (MIR) plasmons in solution-processed, degenerately doped oxide nanoparticles, we demonstrate ultrafast all-optical switching in the MIR region, which features with subpicosecond response speed (with recovery time constant of ‹400 fs) as well as ultrabroadband response spectral range (covering 3...
November 29, 2018: ACS Nano
Jiawei Xu, Mario Konijnenburg, Shuang Song, Hyunsoo Ha, Roland van Wegberg, Chris Van Hoof, Massimo Mazzillo, Giorgio Fallica, Walter De Raedt, Nick Van Helleputte
This paper presents a sub-mW ASIC for multimodal brain monitoring. The ASIC is co-integrated with electrode(s) and optodes (i.e. optical source and detector) as an active sensor to measure electroencephalography (EEG), bio-impedance (BioZ), and near-infrared spectroscopy (NIRS) on scalp. The target is to build a wearable EEG-NIRS headset for low-cost functional brain imaging. The proposed NIRS readout utilizing the near-infrared light can be used to measure the pulse oximetry and blood oxygen saturation (SpO2)...
November 26, 2018: IEEE Transactions on Biomedical Circuits and Systems
Jingjing Liu, Zhangbo Lu, Xianju Zhang, Yangyi Zhang, Haiguang Ma, Yang Ji, Xiangxing Xu, Linwei Yu, Jun Xu, Kunji Chen
Inorganic perovskites have emerged as a promising candidate for light-emitting devices due to their high stability and tunable band gap. However, the power consumption and brightness have always been an issue for perovskite light-emitting diodes (PeLEDs). Here, we improved the luminescence intensity and decreased the current density of the PeLEDs based on CsPbI₃ quantum dots (QDs) and p-type Si substrate through an alternating current (AC) driving mode. For the different driving voltage modes (under a sine pulsed bias or square pulsed bias), a frequency-dependent electroluminescent (EL) behavior was observed...
November 26, 2018: Nanomaterials
Ludovic S Mure, Megumi Hatori, Kiersten Ruda, Giorgia Benegiamo, James Demas, Satchidananda Panda
Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) are indispensable for non-image-forming visual responses that sustain under prolonged illumination. For sustained signaling of ipRGCs, the melanopsin photopigment must continuously regenerate. The underlying mechanism is unknown. We discovered that a cluster of Ser/Thr sites within the C-terminal region of mammalian melanopsin is phosphorylated after a light pulse. This forms a binding site for β-arrestin 1 (βARR1) and β-arrestin 2...
November 27, 2018: Cell Reports
Margaret Driciru, Innocent B Rwego, Benon Asiimwe, Dominic A Travis, Julio Alvarez, Kimberly VanderWaal, Katharine Pelican
BACKGROUND: Anthrax is a zoonotic disease primarily of herbivores, caused by Bacillus anthracis, a bacterium with diverse geographical and global distribution. Globally, livestock outbreaks have declined but in Africa significant outbreaks continue to occur with most countries still categorized as enzootic, hyper endemic or sporadic. Uganda experiences sporadic human and livestock cases. Severe large-scale outbreaks occur periodically in hippos (Hippopotamus amphibious) at Queen Elizabeth Protected Area, where in 2004/2005 and 2010 anthrax killed 437 hippos...
2018: PloS One
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