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Infrared laser

Lucile Richard, Daniele Romanini, Irène Ventrillard
Monitoring nitric oxide at the trace level is required in a large range of applications. We report on a trace gas analyzer optimized for nitric oxide measurements by Optical Feedback Cavity Enhanced Absorption Spectroscopy with an interband cascade laser at 5.3 µm. The short response time of the instrument allows for reaching the level of 50 ppt in only 180 ms. Its stability enables averaging up to 12 min to reach a detection limit of 0.9 ppt. Absolute concentration calibration requires to account for the optical saturation effect that results from the intense absorption line intensity addressed here, in the mid infrared region, in contrast to instruments that are operating in the near infrared region...
June 22, 2018: Sensors
B A Andreev, K E Kudryavtsev, A N Yablonskiy, D N Lobanov, P A Bushuykin, L V Krasilnikova, E V Skorokhodov, P A Yunin, A V Novikov, V Yu Davydov, Z F Krasilnik
The observation of a stimulated emission at interband transitions in monocrystalline n-InN layers under optical pumping is reported. The spectral position of the stimulated emission changes over a range of 1.64 to 1.9 μm with variations of free electron concentration in InN layers from 2·1019  cm-3 to 3·1017  cm-3 . The main necessary conditions for achieving the stimulated emission from epitaxial InN layers are defined. In the best quality samples, a threshold excitation power density is obtained to be as low as 400 W/cm2 at T = 8 K and the stimulated emission is observed up to 215 K...
June 21, 2018: Scientific Reports
Shengchang Zhang, Lin Wu, Jin Cao, Kaili Wang, Yanru Ge, Wanjun Ma, Xueyong Qi, Song Shen
Nanoparticles based multifunctional system exhibits great potential in diagnosis and therapy of rheumatoid arthritis (RA). The size of nanoparticles plays an essential role in biodistribution and cellular uptake, in turn affects the drug delivery efficiency and therapeutic effect. To investigate the optimal size for RA targeting, Fe3 O4 nanoparticles with well-defined particle sizes (70-350 nm) and identical surface properties were developed as model nanoparticles. The synthesized Fe3 O4 nanoparticles exhibited excellent biocompatibility and showed higher temperature response under irradiation of near infrared light...
June 13, 2018: Colloids and Surfaces. B, Biointerfaces
Shan Zong, Xin Wang, Wenhai Lin, Shi Liu, Wei Zhang
Design and synthesis of biocompatible and multi-functional photothermal agents is crucial for effective cancer phototherapy. In order to achieve this ambition, simple D-A-D structural bisbithiophenyl diketopyrrolopyrrole (TDPP) was fabricated. In this molecule, the donor, 2-thiophenylboric acid, was conjugated via Suzuki coupling reaction, which could expand the emission wavelength to the red region of the spectrum. TDPP could self-assemble into stable and uniform nanoparticles (TDPP NPs) in the assistant of amphiphilic Pluronic F-127 polymer...
June 20, 2018: Bioconjugate Chemistry
David R Busch, James Davis, Angela Kogler, Robert M Galler, Ashwin B Parthasarathy, Arjun G Yodh, Thomas F Floyd
The prevention and treatment of spinal cord injury are focused upon the maintenance of spinal cord blood flow, yet no technology exists to monitor spinal cord ischemia. We recently demonstrated continuous monitoring of spinal cord ischemia with diffuse correlation and optical spectroscopies using an optical probe. Prior to clinical translation of this technology, it is critically important to demonstrate the safety profile of spinal cord exposure to the required light. To our knowledge, this is the first report of in situ safety testing of such a monitor...
June 2018: Journal of Biomedical Optics
Xiangling Tian, Hongyu Luo, Rongfei Wei, Chunhui Zhu, Qianyi Guo, Dandan Yang, Fengqiu Wang, Jianfeng Li, Jianrong Qiu
Pulsed lasers operating in the mid-infrared (3-25 µm) are increasingly becoming the light source of choice for a wide range of industrial and scientific applications such as spectroscopy, biomedical research, sensing, imaging, and communication. Up to now, one of the factors limiting the mid-infrared pulsed lasers is the lack of optical switch with a capability of pulse generation, especially for those with wideband response. Here, a semiconductor material of bismuth oxyselenide (Bi2 O2 Se) with a facile processibility, constituting an ultrabroadband saturable absorber for the mid-infrared (actually from the near-infrared to mid-infrared: 0...
June 19, 2018: Advanced Materials
Luiz Philippe da Silva Sergio, Andrezza Maria Côrtes Thomé, Larissa Alexsandra da Silva Neto Trajano, Andre Luiz Mencalha, Adenilson de Souza da Fonseca, Flávia de Paoli
Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are defined as pulmonary inflammation that could occur from sepsis and lead to pulmonary permeability and alveolar edema making them life-threatening diseases. Photobiomodulation (PBM) properties have been widely described in the literature in several inflammatory diseases; although the mechanisms of action are not always clear, this could be a possible treatment for ARDS/ALI. Thus, the aim of this study was to evaluate the mRNA levels from caspase-3 and BCL-2 genes and DNA fragmentation in lung tissue from Wistar rats affected by ALI and subjected to photobiomodulation by exposure to a low power infrared laser (808 nm; 100 mW; 3...
June 20, 2018: Photochemical & Photobiological Sciences
Yanfei Ma, Shuanhong Ma, Yang Wu, Xiaowei Pei, Stanislav N Gorb, Zuankai Wang, Weimin Liu, Feng Zhou
Despite extensive efforts to mimic the fascinating adhesion capability of geckos, the development of reversible adhesives underwater has long been lagging. The appearance of mussels-inspired dopamine chemistry has provided the feasibility to fabricate underwater adhesives; however, for such a system, imitating the reversible and fast dynamic attachment/detachment mechanism of gecko feet still remains unsolved. Here, by synthesizing a thermoresponsive copolymer of poly(dopamine methacrylamide-co-methoxyethyl-acrylate-co-N-isopropyl acrylamide) and then decorating it onto mushroom-shaped poly(dimethylsiloxane) pillar arrays, a novel underwater thermoresponsive gecko-like adhesive (TRGA) can be fabricated, yielding high adhesion during the attachment state above the lower critical solution temperature (LCST) of the copolymer, yet low adhesion during the detachment state below the LCST of the copolymer...
June 19, 2018: Advanced Materials
Mengmeng Ma, Nan Gao, Yuhuan Sun, Xiubo Du, Jinsong Ren, Xiaogang Qu
Adjustable structure, excellent physiochemical properties, and good biocompatibility render polyoxometalates (POMs) as a suitable drug agent for the treatment of Alzheimer's disease (AD). However, previous works using POMs against AD just focus on the inhibition of amyloid-β (Aβ) monomer aggregation. In consideration that both Aβ fibrils and reactive oxygen species (ROS) are closely associated with clinical development of AD symptoms, it would be more effective if POMs can disaggregate Aβ fibrils and eliminate ROS as well...
June 19, 2018: Advanced Healthcare Materials
Rosanna Bivona, Alessandra Tomaselli, Francesco Frigerio
OBJECTIVES: In physical rehabilitation, is diffused the skin irradiation with near infrared laser at a fluence below 140 J/cm2, achieving a bio-stimulating effect that is due to the absorption of radiation in mitochondria rather than the simple heating of tissues. METHODS: In order to deliver radiation without thermal damage of the skin, are used radiation pulses which duration does not allow heat accumulation and propagation far from the irradiated target; this requires laser sources with average power below 10 W implying a safety classification as "potentially dangerous for eye and skin", or "class 4" according to the applicable international standards...
November 2017: Giornale Italiano di Medicina del Lavoro Ed Ergonomia
Olga Gusliakova, Elena N Atochina-Vasserman, Olga Sindeeva, Sergey Sindeev, Sergey Pinyaev, Nikolay Pyataev, Viktor Revin, Gleb B Sukhorukov, Dmitry Gorin, Andrew J Gow
Nano- and microencapsulation has proven to be a useful technique for the construction of drug delivery vehicles for use in vascular medicine. However, the possibility of using these techniques within the lung as an inhalation delivery mechanism has not been previously considered. A critical element of particle delivery to the lung is the degree of penetrance that can be achieved with respect to the airway tree. In this study we examined the effectiveness of near infrared (NIR) dye (Cy7) labeled calcium carbonate (vaterite) particles of 3...
2018: Frontiers in Pharmacology
Angel Fernandez-Bravo, Kaiyuan Yao, Edward S Barnard, Nicholas J Borys, Elizabeth S Levy, Bining Tian, Cheryl A Tajon, Luca Moretti, M Virginia Altoe, Shaul Aloni, Kenes Beketayev, Francesco Scotognella, Bruce E Cohen, Emory M Chan, P James Schuck
Reducing the size of lasers to microscale dimensions enables new technologies 1 that are specifically tailored for operation in confined spaces ranging from ultra-high-speed microprocessors 2 to live brain tissue 3 . However, reduced cavity sizes increase optical losses and require greater input powers to reach lasing thresholds. Multiphoton-pumped lasers4-7 that have been miniaturized using nanomaterials such as lanthanide-doped upconverting nanoparticles (UCNPs) 8 as lasing media require high pump intensities to achieve ultraviolet and visible emission and therefore operate under pulsed excitation schemes...
June 18, 2018: Nature Nanotechnology
Ghanshyam Pilania, Eric Weis, Ethan M Walker, Robert D Gilbertson, Ross E Muenchausen, Evgenya I Simakov
The use of infrared lasers to power accelerating dielectric structures is a developing area of research. Within this technology, the choice of the dielectric material forming the accelerating structures, such as the photonic band gap (PBG) structures, is dictated by a range of interrelated factors including their dielectric and optical properties, amenability to photo-polymerization, thermochemical stability and other target performance metrics of the particle accelerator. In this direction, electronic structure theory aided computational screening and design of dielectric materials can play a key role in identifying potential candidate materials with the targeted functionalities to guide experimental synthetic efforts...
June 18, 2018: Scientific Reports
K S Frahm, O K Andersen, L Arendt-Nielsen, C D Mørch
Objective The objective of this study was to test if offset analgesia could be evoked using a noncontact thermal stimulator. Offset analgesia [J. Neurophysiol. 87:2205-2208, 2002] is defined as an unproportionally large decrease in pain intensity following a slight decrease in stimulation intensity. The importance of differences in thermal properties between human hairy and glabrous skin was investigated. Methods A 20W diode laser (970 nm) was used for the thermal stimulation. A fast (50 images/s) infrared camera measured the skin temperature and a temperature controlled feedback control loop adjusted the laser power...
December 29, 2017: Scandinavian Journal of Pain
Zahra Ebtehaj, Ali Hatef, Mohammad Malekmohammad, Mahmood Soltanolkotabi
Neural stimulation has widespread applications in investigating brain functions, restoring impaired neural functions and treating numerous neurological/psychiatric diseases. Using infrared pulses to stimulate neurons (Infrared Neural Stimulation, INS) offers a direct and noninvasive technique. Recent research has demonstrated that transient heating associated with the absorption of infrared light by the local aqueous medium around the cell membrane can stimulate nerves. One mechanism for this stimulation is due to a thermally induced increase in the membrane electrical capacitance which causes cell depolarization as well as action potential production under certain physiological conditions...
June 18, 2018: Journal of Physical Chemistry. B
Luciana Gonçalves Langella, Heliodora Leão Casalechi, Shaiane Silva Tomazoni, Douglas Scott Johnson, Regiane Albertini, Rodney Capp Pallotta, Rodrigo Labat Marcos, Paulo de Tarso Camillo de Carvalho, Ernesto Cesar Pinto Leal-Junior
When conservative treatments fail, hip osteoarthritis (OA), a chronic degenerative disease characterized by cartilage wear, progressive joint deformity, and loss of function, can result in the need for a total hip arthroplasty (THA). Surgical procedures induced tissue trauma and incite an immune response. Photobiomodulation therapy (PBMt) using low-level laser therapy (LLLT) and/or light-emitting diode therapy (LEDT) has proven effective in tissue repair by modulating the inflammatory process and promoting pain relief...
June 16, 2018: Lasers in Medical Science
B Fatou, P Saudemont, M Duhamel, M Ziskind, C Focsa, M Salzet, I Fournier
Remote Infrared Matrix Assisted Laser Desorption Ionization (Remote IR MALDI) system (SpiderMass) with endogenous water as matrix allows to perform real-time DMPK in vivo. In this work, SpiderMass was used to analyze the impact on metabolite production or release of invalidated pro-protein PC1/3 macrophages by Short RNA (shRNA) versus scramble shRNA with Paclitaxel. Time course in vivo experiments were then performed on the inner and outer faces of patients' forearms or comedo treated with Melascreen (Ducray) containing ascorbyl glucoside...
June 13, 2018: Journal of Biotechnology
Søren Roesgaard, Lichun Meng, Peter Tidemand-Lichtenberg, Jeppe Seidelin Dam, Peter John Rodrigo, Christian Pedersen, Brian Julsgaard
A setup for time-resolved photoluminescence spectroscopy, based on parametric three-wave mixing in a periodically poled lithium niobate crystal, is characterized. Special attention is given to adjusting the phase matching condition by angle tuning of the luminescent light relative to a strong, continuous-wave laser beam within the crystal. The detection system is capable of operating at room temperature and in a wavelength range from 1.55 to 2.20 µm. Its sensitivity is compared to a commercial photomultiplier, and its capability of nanosecond time resolution is demonstrated...
June 15, 2018: Optics Letters
Gengji Zhou, Qian Cao, Franz X Kärtner, Guoqing Chang
We demonstrate a high-power offset-free ultrafast mid-infrared (IR) laser source based on difference-frequency generation (DFG). Powerful signal pulses are obtained by filtering the rightmost spectral lobe of the optical spectra broadened by fiber-optic nonlinearities dominated by self-phase modulation. The resulting mid-IR pulses are tunable from 7 to 18 μm with up to 5.4 mW average power. We experimentally and numerically investigate power scaling of this DFG source and demonstrate that increasing the signal power is an efficient approach for generating high-power mid-IR pulses...
June 15, 2018: Optics Letters
Laurent Huot, Peter Morten Moselund, Peter Tidemand-Lichtenberg, Christian Pedersen
In this Letter, a novel method for the characterization of mid-infrared pulses is presented. A cross-correlator system, with no moving parts, combining ultra-broadband pulsed upconversion detection with fast active electronic delay tuning was built to perform time-resolved spectral characterization of 1.6 ns mid-infrared supercontinuum pulses. Full wavelength/time spectrograms were acquired in steps of 20 ps over a range that can, in theory, extend to microseconds in a matter of seconds, with 48 ps temporal resolution and 22  cm-1 spectral resolution in the 2700-4300 nm range...
June 15, 2018: Optics Letters
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