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Infrared laser

Jiandong Yao, Guowei Yang
Emerging novel applications at the forefront of innovation horizon raise new requirements including good flexibility and unprecedented properties for the photoelectronic industry. On account of diversity in transport and photoelectric properties, 2D layered materials have proven as competent building blocks toward next-generation photodetectors. Herein, an all-2D Bi2 Te3 -SnS-Bi2 Te3 photodetector is fabricated with pulsed-laser deposition. It is sensitive to broadband wavelength from ultraviolet (370 nm) to near-infrared (808 nm)...
April 18, 2018: Small
Jie Wu, Zhifang Li, Yong Li, Alex Pettitt, Feifan Zhou
Pancreatic cancer is a malignant tumor model with high mortality. Many patients are ineligible for surgical resection once diagnosed; therefore, it is important to explore more safe and effective treatment options. This study was designed to determine the therapeutic effect of reduced graphene oxide combined with the near-infrared laser in animal pancreatic cancer. The results showed that reduced graphene oxide has strong light absorption ability between 600 and 1100 nm detected by spectrophotometer. Experimental results of different concentrations of reduced graphene oxide solution under 980-nm laser irradiation at different powers showed that the enhancement of the photothermal conversion effect of reduced graphene oxide depends on reduced graphene oxide concentration and light dose...
January 1, 2018: Technology in Cancer Research & Treatment
Charles Mignon, Natallia E Uzunbajakava, Irene Castellano-Pellicena, Natalia V Botchkareva, Desmond J Tobin
BACKGROUND OBJECTIVES: The past decade has witnessed a rapid expansion of photobiomodulation (PBM), demonstrating encouraging results for the treatment of cutaneous disorders. Confidence in this approach, however, is impaired not only by a lack of understanding of the light-triggered molecular cascades but also by the significant inconsistency in published experimental outcomes, design of the studies and applied optical parameters. This study aimed at characterizing the response of human dermal fibroblast subpopulations to visible and near-infrared (NIR) light in an attempt to identify the optical treatment parameters with high potential to address deficits in aging skin and non-healing chronic wounds...
April 17, 2018: Lasers in Surgery and Medicine
Fengxia Wang, Wei Wang, Xiaobo Niu, Yulong Huang, Ji Zhang
In this study, a second water-soluble polysaccharide (designated as LDP-2) was isolated from the bulbs of Lanzhou Lily (Lilium davidii var. unicolor). Based on monosaccharide composition and methylation analysis, its structural features were investigated using a variety of characterizations, such as size-exclusion chromatography combined with laser light scattering (SEC-LLS), gas chromatography-mass spectroscopy (GC-MS), infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The results demonstrate that LDP-2 is a homogeneous heteropolysaccharide (molecular weight 6...
April 17, 2018: Applied Biochemistry and Biotechnology
Lester Andrews, Han-Gook Cho, Zongtang Fang, Monica Vasiliu, David A Dixon
Laser ablation of tungsten metal provides W atoms which react with phosphine and arsine during condensation in excess argon and neon, leading to major new infrared (IR) absorptions. Annealing, UV irradiation, and deuterium substitution experiments coupled with electronic structure calculations at the density functional theory level led to the assignment of the observed IR absorptions to the E≡WH3 and HE═WH2 molecules for E = P and As. The potential energy surfaces for hydrogen transfer from PH3 to the W were calculated at the coupled-cluster CCSD(T)/complete basis set level...
April 16, 2018: Inorganic Chemistry
Hidde Elferink, Marion E Severijnen, Jonathan Martens, Rens A Mensink, Giel Berden, Jos Oomens, Floris P J T Rutjes, Anouk M Rijs, Thomas J Boltje
Glycosyl cations are crucial intermediates formed during enzymatic and chemical glycosylation. The intrinsic high reactivity and short life-time of these reaction intermediates makes them very challenging to characterize using spectroscopic techniques. Herein, we report the use of collision induced dissociation tandem mass spectrometry to generate glycosyl cations in the gas phase followed by infrared ion spectroscopy using the FELIX infrared free electron laser. The experimentally observed IR spectra were compared to DFT calculated spectra enabling the detailed structural elucidation of elusive glycosyl oxocarbenium and dioxolenium ions...
April 14, 2018: Journal of the American Chemical Society
Dina S Salem, Mahmoud A Sliem, Mohamed El-Sesy, Samia A Shouman, Yehia Badr
A green method was used for producing gold nanoparticles (Au NPs) using chitosan as a natural cationic, biodegradable and biocompatible polymer. In this method, chitosan acts as a reducing and stabilizing agent for the synthesis of Au NPs. Different concentrations of chitosan solutions (0.01%, 0.05%, 0.1%, 0.2%, 0.5% and 1%) were applied. In an attempt to mitigate the side effects of anti-cancer drug, 5-fluorouracil (5-FU), through reducing drug doses in photothermal therapy, the formed positively-charged chitosan-wrapped Au NPs were used as a drug delivery system for negatively charged 5-FU to hepatocellular carcinoma cells (HepG2)...
April 4, 2018: Journal of Photochemistry and Photobiology. B, Biology
Santhosh Kalash Rajendrakumar, Ning-Chu Chang, Adityanarayan Mohapatra, Saji Uthaman, Byeong-Il Lee, Wei-Bor Tsai, In-Kyu Park
To prolong blood circulation and avoid the triggering of immune responses, nanoparticles in the bloodstream require conjugation with polyethylene glycol (PEG). However, PEGylation hinders the interaction between the nanoparticles and the tumor cells and therefore limits the applications of PEGylated nanoparticles for therapeutic drug delivery. To overcome this limitation, zwitterionic materials can be used to enhance the systemic blood circulation and tumor-specific delivery of hydrophobic agents such as IR-780 iodide dye for photothermal therapy...
April 13, 2018: International Journal of Molecular Sciences
Matthew R Majewski, Robert I Woodward, Jean-Yves Carreé, Samuel Poulain, Marcel Poulain, Stuart D Jackson
Optical emission from rare-earth-doped fluoride fibers has thus far been limited to less than 4 μm. We extend emission beyond this limit by employing an indium fluoride (InF3 ) glass fiber as the host, which exhibits an increased infrared transparency over commonly used zirconium fluoride (ZBLAN). Near-infrared pumping of a dysprosium-doped InF3 fiber results in broad emission centered around 4.3 μm, representing the longest emission yet achieved from a fluoride fiber. The first laser emission in an InF3 fiber is also demonstrated from the 3 μm dysprosium transition...
April 15, 2018: Optics Letters
Johannes Rebling, Francisco Javier Oyaga Landa, Xosé Luís Deán-Ben, Alexandre Douplik, Daniel Razansky
Radio frequency (RF) catheter ablation is commonly used to eliminate dysfunctional cardiac tissue by heating via an alternating current. Clinical outcomes are highly dependent on careful anatomical guidance, electrophysiological mapping, and careful RF power titration during the procedure. Yet, current treatments rely mainly on the expertise of the surgeon to assess lesion formation, causing large variabilities in the success rate. We present an integrated catheter design suitable for simultaneous RF ablation and real-time optoacoustic monitoring of the forming lesion...
April 15, 2018: Optics Letters
Chun-Hao Li, Ji-Hong Zhao, Qi-Dai Chen, Jing Feng, Hong-Bo Sun
Non-doped black silicon (b-Si) is fabricated on the surface layer of a near-intrinsic Si substrate by nanosecond (ns) laser direct writing in an argon (Ar) atmosphere. The non-doped samples exhibit a near-unity sub-bandgap (1100∼2500  nm) absorptance of more than 50%. Amazingly, the resistivity of the ns laser irradiated b-Si layer is about five orders of magnitude lower than that of the unprocessed Si substrate. The carrier density of the b-Si layer is about 1×1018   cm-3 , according to the Hall effect measurement...
April 15, 2018: Optics Letters
Abijith S Kowligy, Alex Lind, Daniel D Hickstein, David R Carlson, Henry Timmers, Nima Nader, Flavio C Cruz, Gabriel Ycas, Scott B Papp, Scott A Diddams
We experimentally demonstrate a simple configuration for mid-infrared (MIR) frequency comb generation in quasi-phase-matched lithium niobate waveguides using the cascaded-χ(2) nonlinearity. With nanojoule-scale pulses from an Er:fiber laser, we observe octave-spanning supercontinuum in the near-infrared with dispersive wave generation in the 2.5-3 μm region and intrapulse difference frequency generation in the 4-5 μm region. By engineering the quasi-phase-matched grating profiles, tunable, narrowband MIR and broadband MIR spectra are both observed in this geometry...
April 15, 2018: Optics Letters
Wansun Kim, Sung Ho Lee, Yong Jin Ahn, Seung Ho Lee, Jiwook Ryu, Seok Keun Choi, Samjin Choi
It is very difficult to predict some complications after subarachnoid hemorrhage (SAH), despite rapid advances in medical science. Herein, we introduce a label-free cellulose surface-enhanced Raman spectroscopy (SERS) biosensor chip with pH-functionalized, gold nanoparticle (AuNP)-enhanced localized surface plasmon resonance (LSPR) effects for identification of SAH-induced cerebral vasospasm and hydrocephalus caused by cerebrospinal fluid (CSF). The SERS biosensor chip was implemented by the synthesis reaction of the AuNPs, which were charged positively through pH level adjustment, onto a negatively-charged cellulose substrate with ξ = -30...
April 4, 2018: Biosensors & Bioelectronics
Sanchi Maithani, Santanu Mandal, Abhijit Maity, Mithun Pal, Manik Pradhan
We report on the development of a mid-infrared cavity ring-down spectrometer (CRDS) coupled with a continuous wave (cw) external cavity quantum cascade laser (EC-QCL), operating between 6.0 μm and 6.3 μm, for high-resolution spectroscopic studies of ammonia (NH3) which served as a bench-mark molecule in this spectral region. We characterized the EC-QCL based CRDS system in detail and achieved a noise-equivalent absorption (NEA) coefficient of 2.11 × 10-9 cm-1 Hz-1/2 for a 100 Hz data acquisition rate. We thereafter exploited the system for high-resolution spectroscopic analysis of interference-free 10 transition lines of the ν4 fundamental vibrational band of NH3 centred at ∼6...
April 12, 2018: Analyst
H Wang, X Y Qin, Z Y Li, Z Z Zheng, T Y Fan
OBJECTIVE: To prepare and characterize citric acid (CA)-modified super paramagnetic iron oxide nanoparticles (SPIONs) for magnetic targeting, hyperthermia and magnetic resonance imaging (MRI). METHODS: CA-modified SPIONs (CA-SPIONs) were prepared by co-precipitation method and then the magnetic responsiveness, morphology, particle size, infrared feature, weight percentage of CA, magnetic property and X-ray diffraction pattern of CA-SPIONs were respectively characterized by magnet, transmission electron microscope, laser particle size analyzer, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry-differential thermal analyzer, vibrating sample magnetometer and X-ray diffractometer (XRD)...
April 18, 2018: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
Yuan Jin, Liang Gao, Ji Chen, Chongzhao Wu, John L Reno, Sushil Kumar
A surface-emitting distributed feedback (DFB) laser with second-order gratings typically excites an antisymmetric mode that has low radiative efficiency and a double-lobed far-field beam. The radiative efficiency could be increased by using curved and chirped gratings for infrared diode lasers, plasmon-assisted mode selection for mid-infrared quantum cascade lasers (QCLs), and graded photonic structures for terahertz QCLs. Here, we demonstrate a new hybrid grating scheme that uses a superposition of second and fourth-order Bragg gratings that excite a symmetric mode with much greater radiative efficiency...
April 11, 2018: Nature Communications
Luyuan Chen, Satoshi Komasa, Yoshiya Hashimoto, Shigeki Hontsu, Joji Okazaki
To enhance biocompatibility, osteogenesis, and osseointegration, we coated titanium implants, by krypton fluoride (KrF) pulsed laser deposition, with a thin film of fluoridated hydroxyapatite (FHA). Coating was confirmed by scanning electron microscopy (SEM) and scanning probe microscopy (SPM), while physicochemical properties were evaluated by attenuated reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Calcium deposition, osteocalcin production, and expression of osteoblast genes were significantly higher in rat bone marrow mesenchymal stem cells seeded on FHA-coated titanium than in cells seeded on uncoated titanium...
April 10, 2018: International Journal of Molecular Sciences
Keisou Ishimaru, Takuma Nakajima, Yoshihisa Namiki, Kenji Ryotokuji
Background: We previously reported that pinpoint plantar long-wavelength infrared light irradiation (stress-free therapy; SFT) is useful for alleviating insulin resistance and improving intracranial blood flow in patients with type 2 diabetes mellitus. This study was undertaken to evaluate the influences of SFT on chorioretinal hemodynamics (retinal artery and vein blood flows) as well as atherosclerosis-related factors (TG, LDL-C) and VEGF in patients with dyslipidemia. Methods: Four patients with dyslipidemia received 15-minute irradiation with a stress-free apparatus (far-infrared wavelength, 30 mW)...
March 2018: Integrative Medicine Research
Xiaojie Li, Jiajing Zhou, Xiaonan Dong, Wai-Yin Cheng, Hongwei Duan, Peter C K Cheung
The photothermal cancer therapeutic effect of the AuNR-Glu nanohybrids produced by coating the native gold nanorods (AuNRs) with a natural mushroom biopolymer from Pleurotus tuber-regium sclerotial β-glucan (Glu) were studied in the second near infrared window (NIR-II). AuNR-Glu showed low cytotoxicity and highly biocompatibility due to the surface coating of Glu when compared with the native AuNRs. AuNR-Glu nanohybrids had a high photothermal transduction efficiency (η) of 43.12%, causing effective in vitro cell ablation (over 90% cell death) in both HT-29 (94...
April 7, 2018: Journal of Agricultural and Food Chemistry
Shuting Li, Xiangning Wang, Xinhua Du, Qiang Wu
To compare the visualization of the lesions of diabetic retinopathy (DR) using multicolour scanning laser imaging (MSLI) and conventional colour fundus photography (CFP). The paired images of diabetic patients who underwent same-day MSLI and CFP examinations were reviewed. Combined multicolour (MC) images were acquired simultaneously using three laser wavelengths: blue reflectance (BR, λ = 488 nm), green reflectance (GR, λ = 518 nm) and infrared reflectance (IR, λ = 820 nm). The number of positive DR lesions was calculated using fundus fluorescein angiography as the reference standard...
April 7, 2018: Lasers in Medical Science
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