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https://www.readbyqxmd.com/read/28221028/characterization-of-an-airborne-laser-spark-ion-source-for-ambient-mass-spectrometry
#1
Andreas Bierstedt, Hendrik Kersten, Reto Glaus, Igor B Gornushkin, Ulrich Panne, Jens Riedel
An airborne laser plasma is suggested as an ambient ion source for mass spectrometry. Its fundamental physical properties, such as an excellent spatial and temporal definition, high electron and ion densities and a high effective cross section in maintaining the plasma, make it a promising candidate for future applications. For deeper insights into the plasma properties, the optical plasma emission is examined and compared to mass spectra. The results show a seemingly contradictory behavior, since the emitted light reports the plasma to almost entirely consist of hot elemental ions, while the corresponding mass spectra exhibit the formation of intact molecular species...
February 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28211726/realization-of-translational-symmetry-in-trapped-cold-ion-rings
#2
Hao-Kun Li, Erik Urban, Crystal Noel, Alexander Chuang, Yang Xia, Anthony Ransford, Boerge Hemmerling, Yuan Wang, Tongcang Li, Hartmut Häffner, Xiang Zhang
We crystallize up to 15 ^{40}Ca^{+} ions in a ring with a microfabricated silicon surface Paul trap. Delocalization of the Doppler laser-cooled ions shows that the translational symmetry of the ion ring is preserved at millikelvin temperatures. By characterizing the collective motion of the ion crystals, we identify homogeneous electric fields as the dominant symmetry-breaking mechanism at this energy scale. With increasing ion numbers, such detrimental effects are reduced. We predict that, with only a ten-ion ring, uncompensated homogeneous fields will not break the translational symmetry of the rotational ground state...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28210439/effect-of-endoactivator-and-er-cr-ysgg-laser-activation-of-qmix-as-final-endodontic-irrigant-on-sealer-penetration-a-confocal-microscopic-study
#3
Sarika Chaudhry, Sudha Yadav, Sangeeta Talwar, Mahesh Verma
BACKGROUND: Through chemomechanical debridement of the root canal is a primary requisite for successful endodontic therapy. Thus the aim of this study was to evaluate the effects of using QmiX alone, QmiX with EndoActivator and QmiX with Er,Cr:YSGG laser for final irrigation on sealer penetration into the dentinal tubules. MATERIAL AND METHODS: 75 extracted human mandibular premolar teeth were treated with sodium hypochlorite (NaOCl) irrigation. The samples were divided into 5 groups according to the final irrigation solution used: (1) 17% EDTA and 2...
February 2017: Journal of Clinical and Experimental Dentistry
https://www.readbyqxmd.com/read/28141620/cold-water-mediates-greater-reductions-in-limb-blood-flow-than-whole-body-cryotherapy
#4
Chris Mawhinney, David A Low, Helen Jones, Daniel J Green, Joseph T Costello, Warren Gregson
PURPOSE: Cold-water immersion (CWI) and whole body cryotherapy (WBC) are widely used recovery methods in an attempt to limit exercise-induced muscle damage, soreness and functional deficits after strenuous exercise. The aim of this study was to compare the effects of ecologically-valid CWI and WBC protocols on post-exercise lower limb thermoregulatory, femoral artery and cutaneous blood flow responses. METHODS: Ten males completed a continuous cycle exercise protocol at 70% maximal oxygen uptake until a rectal temperature of 38°C was attained...
January 30, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28140412/a-conformational-study-of-protonated-noradrenaline-by-uv-uv-and-ir-dip-double-resonance-laser-spectroscopy-combined-with-an-electrospray-and-a-cold-ion-trap-method
#5
Hiromichi Wako, Shun-Ichi Ishiuchi, Daichi Kato, Géraldine Féraud, Claude Dedonder-Lardeux, Christophe Jouvet, Masaaki Fujii
The conformer-selected ultraviolet (UV) and infrared (IR) spectra of protonated noradrenaline were measured using an electrospray/cryogenic ion trap technique combined with photo-dissociation spectroscopy. By comparing the UV photo dissociation (UVPD) spectra with the UV-UV hole burning (HB) spectra, it was found that five conformers coexist under ultra-cold conditions. Based on the spectral features of the IR dip spectra of each conformer, two different conformations on the amine side chain were identified...
January 31, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28122875/rapid-identification-of-clinically-relevant-members-of-the-genus-exophiala-by-maldi-tof-mass-spectrometry-and-description-of-two-novel-species-exophiala-campbellii-and-exophiala-lavatrina
#6
Andrew M Borman, Mark Fraser, Adrien Szekely, Daniel E Larcombe, Elizabeth M Johnson
Exophiala is a ubiquitous pleomorphic genus comprising at least forty species, many of which have been associated with superficial, visceral or systemic infections in humans, other mammals or cold-blooded animals. In this study we investigated the potential of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS) for the identification of Exophiala species. A total of 89 isolates (including 50 human and 4 animal clinical isolates) stored in the National Collection of Pathogenic Fungi were identified by PCR amplification and sequencing of the internal transcribed spacer region 1...
January 25, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28110833/a-pilot-study-of-vela-laser-for-en-bloc-resection-of-papillary-bladder-cancer
#7
Zhensheng Zhang, Shuxiong Zeng, Junjie Zhao, Xin Lu, Weidong Xu, Chong Ma, Yang Wang, Xin Chen, Gaozhen Jia, Tie Zhou, Yinghao Sun, Chuanliang Xu
INTRODUCTION: The present study evaluated the safety and efficacy of the Vela laser for en bloc resection of papillary bladder tumors. MATERIALS AND METHODS: From January 2013 to August 2014, 38 patients underwent en bloc resection with the Vela laser and a 26F continuous flow resectoscope or 18F flexible cystoscope. Random cold forceps biopsy samples were also taken. The total operation time, pathologic result, and intraoperative and postoperative complications were recorded...
June 23, 2016: Clinical Genitourinary Cancer
https://www.readbyqxmd.com/read/28108308/role-of-cyclooxygenase-in-the-vascular-response-to-locally-delivered-acetylcholine-in-caucasian-and-african-descent-individuals
#8
Matthew J Maley, James R House, Michael J Tipton, Clare M Eglin
INTRODUCTION: Individuals of African descent (AFD) are more susceptible to non-freezing cold injury (NFCI) compared with Caucasian individuals (CAU). Vasodilatation to acetylcholine (ACh) is lower in AFD compared with CAU in the non-glabrous foot and finger skin sites; the reason for this is unknown. Prostanoids are responsible, in part, for the vasodilator response to ACh, however it is not known whether the contribution differs between ethnicities. METHODS: 12 CAU and 12 AFD males received iontophoresis of ACh (1 w/v%) on non-glabrous foot and finger skin sites following placebo and then aspirin (600mg, single blinded)...
January 17, 2017: Microvascular Research
https://www.readbyqxmd.com/read/28091517/unraveling-the-enhanced-oxygen-vacancy-formation-in-complex-oxides-during-annealing-and-growth
#9
Felix V E Hensling, Chencheng Xu, Felix Gunkel, Regina Dittmann
The reduction of oxides during annealing and growth in low pressure processes is a widely known problem. We hence investigate the influence of mere annealing and of growth in vacuum systems to shed light on the reasons behind the reduction of perovskites. When comparing the existing literature regarding the reduction of the perovskite model material SrTiO3 it is conspicuous that one finds different oxygen pressures required to achieve reduction for vacuum annealing and for chemically controlled reducing atmospheres...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28079524/spatial-heterogeneity-in-the-time-and-frequency-properties-of-skin-perfusion
#10
Michele Sorelli, Zlatka Stoyneva, Irina Mizeva, Leonardo Bocchi
Pathological alterations of the microcirculatory system can be identified by measuring the temporal and spectral properties of Laser Doppler Flowmetry (LDF) signals acquired on the skin, and their changes following physiological stimulation. A wide range of stimulation protocols and measurement locations are observed in literature. Researchers often use non-invasive stimulation techniques, such as post-occlusive hyperaemia, cold tests, and local heating. As concerns the stimulation/recording sites, the forearm, fingers, and toes are typically selected to conduct microcirculation studies...
January 12, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28075022/the-mechanistic-basis-for-photobiomodulation-therapy-of-neuropathic-pain-by-near-infrared-laser-light
#11
Vanessa Milanesi Holanda, Maria Cristina Chavantes, Xingjia Wu, Juanita J Anders
BACKGROUND AND OBJECTIVE: Various irradiances have been reported to be beneficial for the treatment of neuropathic pain with near infrared light. However, the mechanistic basis for the beneficial outcomes may vary based on the level of irradiance or fluence rate used. Using in vivo and in vitro experimental models, this study determined the mechanistic basis of photobiomodulation therapy (PBMT) for the treatment of neuropathic pain using a high irradiance. STUDY DESIGN/MATERIALS AND METHODS: In vitro experiments: Cultured, rat DRG were randomly assigned to control or laser treatment (LT) groups with different irradiation times (2, 5, 30, 60, or 120 seconds)...
January 11, 2017: Lasers in Surgery and Medicine
https://www.readbyqxmd.com/read/28063449/vacuum-ultraviolet-frequency-modulation-spectroscopy
#12
U Hollenstein, H Schmutz, J A Agner, M Sommavilla, F Merkt
Frequency-modulation (FM) spectroscopy has been extended to the vacuum-ultraviolet (VUV) range of the electromagnetic spectrum. Coherent VUV laser radiation is produced by resonance-enhanced sum-frequency mixing (νVUV=2νUV+ν2) in Kr and Xe using two near-Fourier-transform-limited laser pulses of frequencies νUV and ν2. Sidebands generated in the output of the second laser (ν2) using an electro-optical modulator operating at the frequency νmod are directly transferred to the VUV and used to record FM spectra...
January 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28063429/initial-mechanisms-for-the-unimolecular-decomposition-of-electronically-excited-bisfuroxan-based-energetic-materials
#13
Bing Yuan, Elliot R Bernstein
Unimolecular decomposition of energetic molecules, 3,3'-diamino-4,4'-bisfuroxan (labeled as A) and 4,4'-diamino-3,3'-bisfuroxan (labeled as B), has been explored via 226/236 nm single photon laser excitation/decomposition. These two energetic molecules, subsequent to UV excitation, create NO as an initial decomposition product at the nanosecond excitation energies (5.0-5.5 eV) with warm vibrational temperature (1170 ± 50 K for A, 1400 ± 50 K for B) and cold rotational temperature (<55 K). Initial decomposition mechanisms for these two electronically excited, isolated molecules are explored at the complete active space self-consistent field (CASSCF(12,12)/6-31G(d)) level with and without MP2 correction...
January 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28029461/-prevention-of-preterm-birth-by-uterine-cervical-cerclage
#14
L Marcellin
OBJECTIVE: To review the scientific literature on cervical insufficiency and indications of cervical cerclage cervix. MATERIALS AND METHODS: The PubMed database, the Cochrane Library and the recommendations from the French and international obstetrical societies between 1972 and June 2016 have been consulted. RESULTS: Cervical insufficiency is a pathophysiological concept and to date no consensual definition is available: the diagnosis is clinical and discussed retrospectively in case of patients with a history of late miscarriages and/or spontaneous preterm delivery, with asymptomatic dilatation of the cervix (professional consensus)...
October 29, 2016: Journal de Gynécologie, Obstétrique et Biologie de la Reproduction
https://www.readbyqxmd.com/read/28009196/dissipative-double-well-potential-for-cold-atoms-kramers-rate-and-stochastic-resonance
#15
Ion Stroescu, David B Hume, Markus K Oberthaler
We experimentally study particle exchange in a dissipative double-well potential using laser-cooled atoms in a hybrid trap. We measure the particle hopping rate as a function of barrier height, temperature, and atom number. Single-particle resolution allows us to measure rates over more than 4 orders of magnitude and distinguish the effects of loss and hopping. Deviations from the Arrhenius-law scaling at high barrier heights occur due to cold collisions between atoms within a well. By driving the system periodically, we characterize the phenomenon of stochastic resonance in the system response...
December 9, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27932205/cold-induced-sympathetic-tone-modifies-the-impact-of-endothelium-dependent-vasodilation-in-the-finger-pulp
#16
Tone Kristin Bergersen, Maria Skytioti, Maja Elstad
OBJECTIVE: In thermoneutral and cold subjects, the sympathetic nervous system regulates skin blood flow by adjusting frequency of the tonic vasoconstrictor impulses. However, the way these thermoregulatory impulses influence the vascular endothelium is not well known. We studied how the sympathetic nervous system influences endothelium-dependent vasodilation (EDV) caused by shear stress in skin containing arteriovenous anastomoses (AVAs) and arterioles in healthy subjects. METHODS: Thirteen healthy subjects were exposed to thermoneutral (29°C) and cold (22°C) ambient temperatures on separate days...
November 30, 2016: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/27918004/what-devices-to-use-or-not-use-in-skin-of-color
#17
Murad Alam
Lasers and light sources, as well as other energy devices, including radiofrequency, ultrasound, and cold-based therapies, can be used for treatment of aging, dyschromic, or texturally uneven skin. In patients with ethnic skin (ie, skin of color), energy devices are used more cautiously to avoid adverse events. The most common and concerning adverse event is postinflammatory hyperpigmentation. Lower fluence, longer pulse durations, and careful device selection can mitigate the risk of scarring and pigmentary abnormality...
December 2016: Seminars in Cutaneous Medicine and Surgery
https://www.readbyqxmd.com/read/27900382/ultra-fast-preparation-of-high-performance-thermoelectric-bulk-tinisb0-05sn0-95-by-microwave-synthesis
#18
Y Li, C Cheng, Y Lei, M Wang, R D Wan
The antimony-doped half-Heusler thermoelectric bulk TiNiSb0.05Sn0.95 was prepared via ultra-fast 4.5 min microwave synthesis, cold-press forming and 20 min microwave pressureless sintering. The electrical properties i.e. the Seebeck coefficient (S), electrical resistivity (ρ), and carrier concentration (n) and mobility (μ) were measured on a Seebeck coefficient/resistance analysis system (S/RAs) and Hall effect measurement system (HEMS), respectively. The thermal conductivity (κ) was measured on a laser flash thermal analyzer (LFA)...
December 20, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/27891612/neurovascular-mechanisms-underlying-augmented-cold-induced-reflex-cutaneous-vasoconstriction-in-human-hypertension
#19
Jody L Greaney, W Larry Kenney, Lacy M Alexander
KEY POINTS: In hypertensive adults (HTN), cardiovascular risk increases disproportionately during environmental cold exposure. Despite ample evidence of dysregulated sympathetic control of the peripheral vasculature in hypertension, no studies have examined integrated neurovascular function during cold stress in HTN. The findings of the present study show that whole-body cold stress elicits greater increases in sympathetic outflow directed to the cutaneous vasculature and, correspondingly, greater reductions in skin blood flow in HTN...
November 28, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27886497/large-cross-phase-modulations-at-the-few-photon-level
#20
Zi-Yu Liu, Yi-Hsin Chen, Yen-Chun Chen, Hsiang-Yu Lo, Pin-Ju Tsai, Ite A Yu, Ying-Cheng Chen, Yong-Fan Chen
We demonstrate an efficient cross-phase modulation (XPM) based on a closed-loop double-Λ system. The property of the double-Λ medium can be controlled by changing the phases of the applied optical fields. This phase-dependent XPM scheme can achieve large phase modulations at low-light intensities without requiring cavities or tightly focusing laser beams. With this scheme, we observe a π-level phase shift with two pulses, both consisting of eight photons in cold rubidium atoms. Such a novel scheme provides a simple route to generate strong interactions between photons and may have potential applications in all-optical quantum signal processing...
November 11, 2016: Physical Review Letters
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