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Mirna Ayache, Kingman P Strohl
STUDY OBJECTIVES: To assess the interrater reliability and accuracy of overnight pulse oximetry (OPO) interpretations by pulmonary fellows using a comprehensive structured template and after a brief educational session. METHODS: Using the template, four pulmonary and critical care (PCC) fellows interpreted OPO saturation waveforms and parameters extracted from 50 adult consecutive in-laboratory sleep studies. The template included three saturation parameters (mean saturation, oxygen desaturation index [ODI], and cumulative desaturation time) and description of the saturation waveform...
March 30, 2018: Journal of Clinical Sleep Medicine: JCSM: Official Publication of the American Academy of Sleep Medicine
Yu-Chan Guan, Yung-Hsiang Chang, Yi-Chieh Liao, Jin-Long Peng, Li-Bang Wang, Jow-Tsong Shy
In our previous work on the Lamb-dips of the ν2 fundamental band transitions of H3 + , the saturated absorption spectrum was obtained by third-derivative spectroscopy using frequency modulation with an optical parametric oscillator (OPO). However, frequency modulation also caused errors in the absolute frequency determination. To solve this problem, we built a tunable offset locking system to lock the pump frequency of the OPO to an iodine-stabilized Nd:YAG laser. With this improvement, we were able to scan the OPO idler frequency precisely and obtain the saturated absorption profile using intensity modulation...
March 28, 2018: Journal of Chemical Physics
Callum F O'Donnell, S Chaitanya Kumar, K T Zawilski, P G Schunemann, M Ebrahim-Zadeh
We report a high-repetition-rate femtosecond optical parametric oscillator (OPO) for the deep-infrared (deep-IR) based on type-I critical phase-matching in CdSiP2 (CSP), pumped directly by a Ti:sapphire laser. Using angle-tuning in the CSP crystal, the OPO can be continuously tuned across 7306-8329 nm (1201-1369  cm-1 ) in the deep-IR. It delivers up to 18 mW of idler average power at 7306 nm and >7  mW beyond 8000 nm at 80.5 MHz repetition rate, with the spectra exhibiting bandwidths of >150  nm across the tuning range...
April 1, 2018: Optics Letters
Hanshuo Wu, Peng Wang, Jiaxin Song, Jun Ye, Jiangming Xu, Xiao Li, Pu Zhou
Random fiber laser, as a kind of novel fiber laser that utilizes random distributed feedback as well as Raman gain, has become a research focus owing to its advantages of wavelength flexibility, modeless property and output stability. Herein, a tunable optical parametric oscillator (OPO) enabled by a random fiber laser is reported for the first time. By exploiting a tunable random fiber laser to pump the OPO, the central wavelength of idler light can be continuously tuned from 3977.34 to 4059.65 nm with stable temporal average output power...
March 5, 2018: Optics Express
S Perez-Protto, R Nazemian, M Matta, P Patel, K J Wagner, S Q Latifi, D J Lebovitz, J D Reynolds
Many deceased by neurologic criteria donors are administered inhalational agents during organ recovery surgery-a process that is characterised by warm and cold ischaemia followed by warm reperfusion. In certain settings, volatile anaesthetics (VA) are known to precondition organs to protect them from subsequent ischaemia-reperfusion injury. As such, we hypothesised that exposure to VA during organ procurement would improve post-graft survival. Lifebanc (organ procurement organisation [OPO] for NE Ohio) provided the investigators with a list of death by neurologic criteria organ donors cared for at three large tertiary hospitals in Cleveland between 2006 and 2016-details about the surgical recovery phase were extracted from the organ donors' medical records...
March 2018: Anaesthesia and Intensive Care
Francisca A Abanyie, Emily Valice, Kristin W Delli Carpini, Elizabeth B Gray, Isabel McAuliffe, Peter V Chin-Hong, Sukwan Handali, Susan P Montgomery, Shirish Huprikar
BACKGROUND: Targeted donor screening for strongyloidiasis performed at the time of organ procurement can prevent this life-threatening donor-derived infection. METHOD: The Association of Organ Procurement Organizations surveyed members to determine the number of U.S. organ procurement organizations (OPOs) performing donor screening for Strongyloides infection and their screening practices. RESULTS: All 58 OPOs responded to the survey. Only six (10%) currently screen donors for strongyloidiasis; most OPOs started 6-36 months before the survey, one started 6 years prior...
March 7, 2018: Transplant Infectious Disease: An Official Journal of the Transplantation Society
Jessica Lindemann, Leigh Anne Dageforde, Neeta Vachharajani, Emily Stahlschmidt, Diane Brockmeier, Jason R Wellen, Adeel Khan, William C Chapman, Majella Doyle
BACKGROUND: Donation after cardiac death (DCD) is one method of organ donation. Nationally, more than half of evaluated DCD donors do not yield transplantable organs. There is no algorithm for predicting which DCD donors will be appropriate for organ procurement. DCD program costs from an organ procurement organization (OPO) accounting for all evaluated donors have not been reported. STUDY DESIGN: Hospital, transportation, and supply costs of potential DCD donors evaluated at a single OPO from January 2009 to June 2016 were collected...
March 2, 2018: Journal of the American College of Surgeons
Vera Safronova, Andrey Belimov, Anna Sazanova, Elizaveta Chirak, Alla Verkhozina, Irina Kuznetsova, Evgeny Andronov, Jan Puhalsky, Igor Tikhonovich
Ten rhizobial strains were isolated from root nodules of a relict legume Oxytropis popoviana Peschkova. For identification of the isolates sequencing of rrs, ITS (internal transcribed spacer) region and housekeeping genes recA, glnII and rpoB was used. Nine fast-growing isolates were Mesorhizobium-related: eight strains were identified as M. japonicum and one isolate belonged to M. kowhaii. The only slow-growing isolate was identified as Bradyrhizobium sp. Two strains, M. japonicum Opo-242 and Bradyrhizobium sp...
March 2, 2018: Molecular Plant-microbe Interactions: MPMI
Brian Cole, Lew Goldberg, Stephen Chinn, Leonard A Pomeranz, Kevin T Zawilski, Peter G Schunemann, John McCarthy
We describe a compact and efficient mid-infrared (mid-IR) source based on zinc germanium phosphide (ZGP) and cadmium silicon phosphide (CSP) optical parametric oscillators (OPOs), operating in near degenerate condition, directly pumped by a 1.94 μm thulium (Tm)-doped yttrium-aluminum-perovskite (YAP) laser. The Tm:YAP laser is passively Q-switched by a chromium-doped zinc sulfide saturable absorber, and is operated to 4 W average power with a peak power of 29 kW. The laser emission was used to pump CSP and ZGP doubly resonant linear OPO cavities, generating a maximum 3...
March 1, 2018: Optics Letters
Chenchen Wan, Peng Li, Axel Ruehl, Ingmar Hartl
Synchronously pumped optical parametric oscillators (OPOs) are important tools for frequency comb (FC) generation in the mid-IR spectral range, where few suitable laser gain materials exist. For degenerate OPOs, self-phase-locking to the pump FC has been demonstrated. Here, we present a phase noise study of the carrier envelope offset frequency, revealing a -6  dB reduction compared to the pump FC over a wide Fourier frequency range. These results demonstrate that a degenerate OPO can be an ideal coherent frequency divider without any excess noise...
March 1, 2018: Optics Letters
Marc Jankowski, Alireza Marandi, C R Phillips, Ryan Hamerly, Kirk A Ingold, Robert L Byer, M M Fejer
We report the first demonstration of a regime of operation in optical parametric oscillators (OPOs), in which the formation of temporal simultons produces stable femtosecond half-harmonic pulses. Simultons are simultaneous bright-dark solitons of a signal field at frequency ω and the pump field at 2ω, which form in a quadratic nonlinear medium. The formation of simultons in an OPO is due to the interplay of nonlinear pulse acceleration with the timing mismatch between the pump repetition period and the cold-cavity round-trip time and is evidenced by sech^{2} spectra with broad instantaneous bandwidths when the resonator is detuned to a slightly longer round-trip time than the pump repetition period...
February 2, 2018: Physical Review Letters
Cong Sun, Wei Wei, Xiaoqiang Zou, Jianhua Huang, Qingzhe Jin, Xingguo Wang
Triacylglycerol (TAG) composition in 180 commercial infant, follow-on and growing-up formulas with different fat sources (plant oil, cow's milk and goat's milk) were analyzed and compared with mature human milk (MHM). TAGs in formulas were greatly affected by fat source. Formulas contained higher proportions of TAGs with short-chain/medium-chain saturated fatty acids, OOO and acyl carbon number (ACN) 54, and lower proportions of ACN 52 than MHM. There were significant differences in the content and stereochemical structure of OPL and OPO between formulas and MHM...
June 30, 2018: Food Chemistry
Aurelien Trivella, Tobias Nils Wassermann, Carine Manca Tanner, Nils O B Luettschwager, Stephane Coussan
UV and IR photochemistries of malonaldehyde, the simplest molecule exhibiting an intramolecular proton exchange, have been studied in four cryogenic matrices at 4.3 K, N2, Ne, Ar and Xe. Samples have been irradiated using a UV and IR OPO type tunable laser, and with a broad band UV mercury lamp. UV and IR spectra have been recorded and compared with theoretical calculations carried out at the SAC-CI/6-31++G(d,p) (UV transitions) and B3LYP/6-311++G(2d,2p) (IR spectra) levels of theory. After de- position, the intramolecularly H-bonded form is found exclusively, while several open forms are formed upon UV irradiation...
February 8, 2018: Journal of Physical Chemistry. A
Martin Schellhorn, Gerhard Spindler, Marc Eichhorn
Divergence compensation, optimization of the optical-to-optical efficiency, and high beam quality of signal and idler beams of a high-energy mid-infrared ZnGeP2 (ZGP) optical parametric oscillator (OPO) have been demonstrated by use of a Galilean telescope inside the nonplanar fractional-image-rotation enhancement (FIRE) ring resonator. With a small variation of the distance between the lenses of the telescope, the divergences of signal and idler beams could be adjusted. Up to 36 mJ of mid-infrared pulse energy in the 3-5 µm wavelength range is obtained with 92 mJ of pump energy on crystal...
January 22, 2018: Optics Express
Haitao Huang, Hui Wang, Shiqiang Wang, Deyuan Shen
We demonstrated a novel cascaded nonlinear frequency conversion that integrated OPO, SFG and SRS in two KTA crystals, realizing an efficient wavelength conversion from 1064 nm to multi-wavelength around 630 nm. The OPO and SRS were both performed in an x-cut KTA crystal to realize a noncritically phase-matched OPO and X(ZZ)X Raman conversion. The SFG was achieved in a (θ = 90◦, φ = 24.3◦)-cut KTA crystal with a type-II phase-matching configuration. Benefitting from the strong pulse-narrowing induced by the combined effect of OPO and SRS, a minimum pulse width of 13...
January 22, 2018: Optics Express
Ajanta Barh, Peter Tidemand-Lichtenberg, Christian Pedersen
Low noise detection with state-of-the-art mid-infrared (MIR) detectors (e.g., PbS, PbSe, InSb, HgCdTe) is a primary challenge owing to the intrinsic thermal background radiation of the low bandgap detector material itself. However, researchers have employed frequency upconversion based detectors (UCD), operable at room temperature, as a promising alternative to traditional direct detection schemes. UCD allows for the use of a low noise silicon-CCD/camera to improve the SNR. Using UCD, the noise contributions from the nonlinear material itself should be evaluated in order to estimate the limits of the noise-equivalent power of an UCD system...
February 5, 2018: Optics Express
Li-Jiao He, Ke Liu, Yong Bo, Zhao Liu, Xiao-Jun Wang, Feng Yang, Lei Yuan, Qin-Jun Peng, Da-Fu Cui, Zu-Yan Xu
We have proposed a novel approach to realize a high-energy ultrafast optical parametric oscillator (OPO) by intracavity pumping in a regenerative amplifier. In this way, we have experimentally demonstrated an unprecedented pulse energy of 30.5 μJ from a 1.5-μm singly resonant synchronously pumped OPO at a pulse repetition rate of 10 kHz with a pulse width of 7.0 ps. To the best of our knowledge, this is the highest pulse energy from an ultrafast laser OPO.
February 1, 2018: Optics Letters
Delphine Descloux, Cédric Laporte, Jean-Baptiste Dherbecourt, Jean-Michel Melkonian, Myriam Raybaut, Cyril Drag, Antoine Godard
This erratum is to correct an error made in our paper [Opt. Lett.40, 280 (2015)OPLEDP0146-959210.1364/OL.40.000280] regarding the sign of the quasi-phase matching chirp rate.
February 1, 2018: Optics Letters
David S Goldberg, Teresa Shafer, Laura Siminoff
No abstract text is available yet for this article.
January 18, 2018: Transplantation
Haiyong Zhu, Junhong Guo, Yanmin Duan, Jing Zhang, Yongchang Zhang, Changwen Xu, Hongyan Wang, Dianyuan Fan
An intra-cavity optical parametric oscillator (OPO) emitting at 1.7 μm derived by Nd:YVO4 self-Raman laser is demonstrated in this Letter, with a KTiOAsO4 (KTA) crystal used as nonlinear optical crystal. A laser diode end-pumped acousto-optic Q-switched Nd:YVO4 self-Raman laser at 1176 nm was employed as the pump source. At an incident pump power of 12.1 W and a pulse repetition frequency of 60 kHz, average output power up to 1.2 W signal light at 1742 nm was obtained, with diode-to-signal conversion efficiency of 10%...
January 15, 2018: Optics Letters
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