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Infrared laser

Joseph T Brice, Tao Liang, Paul L Raston, Anne B McCoy, Gary E Douberly
Sequential capture of OH and CO by superfluid helium droplets leads exclusively to the formation of the linear, entrance-channel complex, OH-CO. This species is characterized by infrared laser Stark and Zeeman spectroscopy via measurements of the fundamental OH stretching vibration. Experimental dipole moments are in disagreement with ab initio calculations at the equilibrium geometry, indicating large-amplitude motion on the ground state potential energy surface. Vibrational averaging along the hydroxyl bending coordinate recovers 80% of the observed deviation from the equilibrium dipole moment...
September 28, 2016: Journal of Chemical Physics
Sylvestre Twagirayezu, Gregory E Hall, Trevor J Sears
Sub-Doppler, saturation dip, spectra of lines in the v1 + v3, v1 + 2v4, and v3 + 2v4 bands of (14)NH3 have been measured by frequency comb-referenced diode laser absorption spectroscopy. The observed spectral line widths are dominated by transit time broadening and show resolved or partially-resolved hyperfine splittings that are primarily determined by the (14)N quadrupole coupling. Modeling of the observed line shapes based on the known hyperfine level structure of the ground state of the molecule shows that, in nearly all cases, the excited state level has hyperfine splittings similar to the same rotational level in the ground state...
October 14, 2016: Journal of Chemical Physics
Joel D Leger, Clyde Varner, Igor V Rubtsov
Fifth-order multidimensional infrared spectroscopy with heterodyned detection was carried out in the three-beam dual-frequency configuration. Numerous 5th-order cross peaks were detected for the 4-azidobutyrate-N-hydroxysuccinimide ester compound in solution involving several vibrational modes ranging in frequency from 1045 to 2100 cm(-1). Cross peaks involving overtones (2X/Z) and combination bands (XY/Z) among the tags, modes X and Y excited by the first two mid-IR laser pulses, and the reporter, modes Z excited by the third laser pulse, were acquired and the factors affecting the amplitude of 5th-order cross peaks are discussed...
October 21, 2016: Journal of Chemical Physics
Csaba Szekrényesi, Gábor László Sándor, Andrea Gyenes, Huba Kiss, Tamás Filkorn, Zoltán Nagy
INTRODUCTION: Thermal conditions during photorefractive keratectomy might be an important issue related to the corneal wound healing and long-term outcomes. AIM: Authors tried to find out the importance of temperature conditions during the treatment. METHOD: One eye of 90 patients has been included into the study. Photorefractive keratoctomy was applied with Carl Zeiss MEL 70, MEL 80 and Wavelight Allegretto excimer lasers. EBRO TLC 730 infrared thermometer was used for the measurement of surface temperature of the cornea before epithelial removal, as well as before and after the treatment...
October 2016: Orvosi Hetilap
Ismail Ocsoy, Nuran Isiklan, Sena Cansiz, Nalan Özdemir, Weihong Tan
Aptamer-functionalized magnetic graphene oxide conjugates loaded with indocyanine green (ICG) dye, or Apt@ICG@mGO, have been successfully developed for dual-targeted photothermal and photodynamic therapy. In general, a drug or its carrier or their dosage can be imprtant important issues in terms of toxicity. However, in this system, each component used is quite safe, biocompatibe and clean. For instance, ICG, a Food and Drug Administration (FDA) approved near-infrared (NIR) dye, serves as both a photothermal and photodynamic agent...
2016: RSC Advances
Chengdong Zhang, Xiaoyan Chen
Dispersing carbon nanomaterials with the aid of sonication has become a widely used procedure for generating homogenous solutions. A systematic study was performed to evaluate the effects of a practical sample preparation procedure that involves mild sonication with/without low concentrations of hydrogen peroxide. Hydrogen peroxide is ubiquitously present in surface water and involved in advanced oxidation processes. Significant oxidation was observed for fullerene in the liquid phase, whereas an appreciable amount of hydrogen was covalently attached to the carbon cage of solid fullerene...
January 2017: Ultrasonics Sonochemistry
Ang Li, Xiang Li, Xujiang Yu, Wei Li, Ruyi Zhao, Xiao An, Daxiang Cui, Xiaoyuan Chen, Wanwan Li
In this work, we report a successful synthesis of copper bismuth sulfide nanorods (NRs) with broad and strong photoabsorption ranging from ultraviolet (UV) to near-infrared (NIR) wavelengths, which can be used as a 1064 nm-laser-driven photothermal agent with the photothermal conversion efficiency of 40.7%, noticeably higher than most of the reported PTT agents working in NIR-II window. The as-prepared PEGylated Cu3BiS3 NRs were used as photoacoustic imaging (PAI) and CT imaging agents due to their strong NIR absorption and large X-ray attenuation coefficient of bismuth...
October 12, 2016: Biomaterials
Abdul K Parchur, Qifei Li, Anhong Zhou
We report the synthesis, characterization, and application of Prussian blue (PB) functionalized CaMoO4:Eu@SiO2@Au nanorod hybrid nanoparticles (HNPs), with multimodal capabilities such as fluorescence imaging, surface-enhanced Raman spectroscopy (SERS) detection and photothermal therapy (PTT). The average size of CaMoO4:Eu@SiO2 NPs was 206 nm. The HNPs are highly dispersible in water for several weeks without settling and show a strong absorption in the near-infrared region, overlapping with the PB absorption between 600 nm and 1000 nm and the surface plasmon resonance of Au nanorods around 800 nm...
October 21, 2016: Biomaterials Science
Qian Chen, Ligeng Xu, Chao Liang, Chao Wang, Rui Peng, Zhuang Liu
A therapeutic strategy that can eliminate primary tumours, inhibit metastases, and prevent tumour relapses is developed herein by combining adjuvant nanoparticle-based photothermal therapy with checkpoint-blockade immunotherapy. Indocyanine green (ICG), a photothermal agent, and imiquimod (R837), a Toll-like-receptor-7 agonist, are co-encapsulated by poly(lactic-co-glycolic) acid (PLGA). The formed PLGA-ICG-R837 nanoparticles composed purely by three clinically approved components can be used for near-infrared laser-triggered photothermal ablation of primary tumours, generating tumour-associated antigens, which in the presence of R837-containing nanoparticles as the adjuvant can show vaccine-like functions...
October 21, 2016: Nature Communications
Erik J Oerter, Alexei Perelet, Eric Pardyjak, Gabriel Bowen
RATIONALE: The fast and accurate measurement of H and O stable isotope compositions (δ(2) H and δ(18) O values) of soil and sediment pore water remains an impediment to scaling-up the application of these isotopes in soil and vadose hydrology. Here we describe a method and its calibration to measuring soil and sediment pore water δ(2) H and δ(18) O values using a water vapor-permeable probe coupled to an Isotope Ratio Infrared Spectroscopy analyzer. METHODS: We compare the water vapor probe method with a vapor direct equilibration method, and vacuum extraction with liquid water analysis...
October 20, 2016: Rapid Communications in Mass Spectrometry: RCM
Hongjun Xia, Guangping Wan, Junlong Zhao, Jiawei Liu, Quan Bai
High performance liquid chromatography (HPLC) is a kind of efficient separation technology and has been used widely in many fields. Micro-sized porous silica microspheres as the most popular matrix have been used for fast separation and analysis in HPLC. In this paper, the monodisperse large-porous silica microspheres with controllable size and structure were successfully synthesized with polymer microspheres as the templates and characterized. First, the poly(glycidyl methacrylate-co-ethyleneglycol dimethacrylate) microspheres (PGMA-EDMA) were functionalized with tetraethylenepentamine (TEPA) to generate amino groups which act as a catalyst in hydrolysis of tetraethyl orthosilicate (TEOS) to form Si-containing low molecular weight species...
October 13, 2016: Journal of Chromatography. A
Qiangbing Guo, Meixi Ji, Yunhua Yao, Meng Liu, Zhi-Chao Luo, Shian Zhang, Xiaofeng Liu, Jianrong Qiu
Here, we show that solution-processed Cu-Sn-S semiconductor nanocrystals (NCs) demonstrate a tunable localized surface plasmon resonance band in the near infrared region, where strong saturable absorption occurs. A saturable absorber based on these plasmonic NCs enables the construction of a stable mode-locked femtosecond fiber laser operating at the telecommunication band.
October 20, 2016: Nanoscale
N V Klementieva, K A Lukyanov, N M Markina, S A Lukyanov, E V Zagaynova, A S Mishin
Recently, an unusual phenomenon of primed conversion of fluorescent protein Dendra2 by combined action of blue (488 nm) and near-infrared (700-780 nm) lasers was discovered. Here we demonstrate that primed conversion can be induced by red lasers (630-650 nm) common for most confocal and single molecule detection microscopes.
October 20, 2016: Chemical Communications: Chem Comm
Takashi Buma, Jessica L Farland, Margaret R Ferrari
We demonstrate optical resolution photoacoustic microscopy (OR-PAM) of lipid-rich tissue using a multi-wavelength pulsed laser based on nonlinear fiber optics. 1047 nm laser pulses are converted to 1098, 1153, 1215, and 1270 nm pulses via stimulated Raman scattering in a graded-index multimode fiber. Multispectral PAM of a lipid phantom is demonstrated with our low-cost and simple technique.
September 2016: Photoacoustics
Bingjiang Zhou, Yunzheng Li, Guangle Niu, Minhuan Lan, Qingyan Jia, Qionglin Liang
Given their easy structural modification and good biocompatibility advantages, near-infrared (NIR) organic dyes with a large molar extinction coefficient while a super-low fluorescence quantum yield show considerable potential application in photothermal therapy (PTT). Herein, a new NIR-absorbing asymmetric cyanine dye, namely, RC, is designed and synthesized via the hybrid of rhodamine and hemicyanine derivatives. RC-BSA nanoparticles (NPs) are fabricated by using the bovine serum albumin (BSA) matrix. The NPs exhibit a strong NIR absorption peak at ~868 nm and 28...
October 19, 2016: ACS Applied Materials & Interfaces
Aram Gragossian, Denis V Seletskiy, Mansoor Sheik-Bahae
The interaction of intense near- and mid-infrared laser pulses with rare gases has produced bursts of radiation with spectral content extending into the extreme ultraviolet and soft x-ray region of electromagnetic spectrum. On the other end of the spectrum, laser-driven gas plasmas has been shown to produce coherent sub-harmonic optical waveforms, covering from terahertz (THz) to mid- and near-infrared frequency spectral band. Both processes can be enhanced via a combination of a driving field and its second harmonic...
October 19, 2016: Scientific Reports
Cletus Cheyuo, Walter Grand, Lucia L Balos
BACKGROUND: Cytoarchitectural neuroimaging remains critical for diagnosis of many brain diseases. Fluorescent dye-enhanced, near-infrared confocal in situ cellular imaging of the brain has been reported. However, impermeability of the blood-brain barrier to most fluorescent dyes limits clinical utility of this modality. The differential degree of reflectance from brain tissue with unenhanced near-infrared imaging may represent an alternative technique for in situ cytoarchitectural neuroimaging...
October 15, 2016: World Neurosurgery
Nathan S Hart, Melinda Fitzgerald
Red-near-infrared light has been used for a range of therapeutic purposes. However, clinical trials of near-infrared laser light for treatment of stroke were abandoned after failing interim futility analyses. Lack of efficacy has been attributed to sub-optimal treatment parameters and low penetrance of light to affected brain regions. Here, we assess penetrance of wavelengths from 450-880 nm in human post-mortem samples, and demonstrate that human skin, skull bone and brain transmits therapeutically relevant quantities of light from external sources at wavelengths above 600nm...
September 2016: Discovery Medicine
Tomasz P Wrobel, Prabuddha Mukherjee, Rohit Bhargava
Infrared (IR) spectroscopic imaging has been used to measure the composition and orientation of polymeric systems for decades. IR microscopy can provide detailed views of microscopic regions, allowing the observation of both morphology and molecular properties of a sample, but involves a trade-off between the spatial extent and details of molecular content. Here we describe an approximately two orders of magnitude faster approach to measure the spherulitic structure and molecular orientation in large semi-crystalline polymer samples compared to extant Fourier transform infrared (FT-IR) spectroscopic imaging...
October 18, 2016: Analyst
Thomas P J Blaikie, John Howard Couper, Gus Hancock, Philip L Hurst, Robert Peverall, Graham Richmond, Grant A D Ritchie, David Taylor, Kevin Valentine
A portable and compact device is demonstrated for measuring acetone in breath samples. The device features a 7 cm long high finesse optical cavity as an optical sensor that is coupled to a miniature adsorption preconcentrator containing 0.5 g of polymer material. Acetone is trapped out of breath and released into the optical cavity where it is probed by a near-infrared diode laser operating at ~1670 nm. With an optical cavity mirror reflectivity of 99.994 % a limit of detection of 159 ppbv (1σ) is demonstrated on samples from breath bags...
October 18, 2016: Analytical Chemistry
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