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https://www.readbyqxmd.com/read/28341834/grating-chips-for-quantum-technologies
#1
James P McGilligan, Paul F Griffin, Rachel Elvin, Stuart J Ingleby, Erling Riis, Aidan S Arnold
We have laser cooled 3 × 10(6 87)Rb atoms to 3 μK in a micro-fabricated grating magneto-optical trap (GMOT), enabling future mass-deployment in highly accurate compact quantum sensors. We magnetically trap the atoms, and use Larmor spin precession for magnetic sensing in the vicinity of the atomic sample. Finally, we demonstrate an array of magneto-optical traps with a single laser beam, which will be utilised for future cold atom gradiometry.
March 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28339248/anderson-transition-of-cold-atoms-with-synthetic-spin-orbit-coupling-in-two-dimensional-speckle-potentials
#2
Giuliano Orso
We investigate the metal-insulator transition occurring in two-dimensional (2D) systems of noninteracting atoms in the presence of artificial spin-orbit interactions and a spatially correlated disorder generated by laser speckles. Based on a high order discretization scheme, we calculate the precise position of the mobility edge and verify that the transition belongs to the symplectic universality class. We show that the mobility edge depends strongly on the mixing angle between Rashba and Dresselhaus spin-orbit couplings...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28323482/constraints-on-the-early-terrestrial-surface-uv-environment-relevant-to-prebiotic-chemistry
#3
Sukrit Ranjan, Dimitar D Sasselov
The UV environment is a key boundary condition to abiogenesis. However, considerable uncertainty exists as to planetary conditions and hence surface UV at abiogenesis. Here, we present two-stream multilayer clear-sky calculations of the UV surface radiance on Earth at 3.9 Ga to constrain the UV surface fluence as a function of albedo, solar zenith angle (SZA), and atmospheric composition. Variation in albedo and latitude (through SZA) can affect maximum photoreaction rates by a factor of >10.4; for the same atmosphere, photoreactions can proceed an order of magnitude faster at the equator of a snowball Earth than at the poles of a warmer world...
March 2017: Astrobiology
https://www.readbyqxmd.com/read/28322007/one-electron-initiated-two-electron-oxidation-of-water-by-aluminum-porphyrins-with-earth-s-most-abundant-metal-ion
#4
Fazalurahman Kuttassery, Siby Mathew, Shogo Sagawa, Sebastian Nybin Remello, Arun Thomas, Daisuke Yamamoto, Satomi Onuki, Yu Nabetani, Hiroshi Tachibana, Haruo Inoue
We report here a new molecular catalyst for efficient water splitting, aluminum porphyrins (tetra-methylpyridiniumylporphyrinatealuminum: AlTMPyP), containing the Earth's most abundant metal as the central ion. One-electron oxidation of the aluminum porphyrin initiates the two-electron oxidation of water to form hydrogen peroxide as the primary reaction product with the lowest known overpotential (97 mV). The aluminum-peroxo complex was clearly detected by a cold-spray ionization mass-spectrometry in HRMS mode and the structure of the intermediate was further confirmed using laser-Raman spectroscopy, indicating the hydroperoxy complex of AlTMPyP to be the key intermediate in the reaction...
March 20, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28294217/competition-between-stacked-and-hydrogen-bonded-structures-of-cytosine-aggregates
#5
Jorge González, Imanol Usabiaga, Pedro F Arnaiz, Iker León, Rodrigo Martínez, Judith Millán, José A Fernández
The four bases of DNA constitute what is known as the "alphabet of life". Their combination of proton-donor and acceptor groups and aromatic rings allows them to form stacking structures and at the same time establish hydrogen bonds with their counterparts, resulting in the formation of the well-known double-helix structure of DNA. Here we explore the aggregation preferences of cytosine in supersonic expansions, using a combination of laser spectroscopic techniques and computations. The data obtained from the experiments carried out in the cold and isolated environment of the expansion allowed us to establish which are the leading interactions behind aggregation of cytosine molecules...
March 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28281457/evaluation-of-the-effect-of-sildenafil-on-the-microvascular-blood-flow-in-patients-with-systemic-sclerosis-a-randomised-double-blind-placebo-controlled-study
#6
Fernando V Andrigueti, Pâmela C C Ebbing, Maria I Arismendi, Cristiane Kayser
OBJECTIVES: To evaluate the effect of sildenafil as add-on therapy on the microvascular blood flow in patients with Raynaud's phenomenon (RP) secondary to systemic sclerosis (SSc). METHODS: In this double-blind, placebo-controlled study, 41 patients with RP secondary to SSc were randomly assigned to receive oral sildenafil 100 mg/day (21 patients, mean age 47.2 years) or placebo (20 patients, mean age 41.6 years) for 8 weeks. Patients were evaluated at baseline, 8 weeks after treatment, and 2 weeks after the end of the treatment...
March 9, 2017: Clinical and Experimental Rheumatology
https://www.readbyqxmd.com/read/28262861/dense-ionization-and-subsequent-non-homogeneous-radical-mediated-chemistry-of-femtosecond-laser-induced-low-density-plasma-in-aqueous-solutions-synthesis-of-colloidal-gold
#7
Hakim Belmouaddine, Minghan Shi, Paul-Ludovic Karsenti, Ridthee Meesat, Léon Sanche, Daniel Houde
The "cold" low density plasma channels generated by the filamentation of powerful femtosecond laser pulses in aqueous solutions constitute a source of dense ionization. Here, we probed the radiation-assisted chemistry of water triggered by laser ionization via the radical-mediated synthesis of nanoparticles in gold chloride aqueous solutions. We showed that the formation of colloidal gold originates from the reduction of trivalent ionic gold initially present in solution by the reactive radicals (e.g. hydrated electrons) produced upon the photolysis of water...
March 6, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28259189/measuring-intermolecular-binding-energies-by-laser-spectroscopy
#8
Richard Knochenmuss, Surajit Maity, Géraldine Féraud, Samuel Leutwyler
The ground-state dissociation energy, D0(S0), of isolated intermolecular complexes in the gas phase is a fundamental measure of the interaction strength between the molecules. We have developed a three-laser, triply resonant pump-dump-probe technique to measure dissociation energies of jet-cooled M•S complexes, where M is an aromatic chromophore and S is a closed-shell 'solvent' molecule. Stimulated emission pumping (SEP) via the S0→S1 electronic transition is used to precisely 'warm' the complex by populating high vibrational levels v" of the S0 state...
February 22, 2017: Chimia
https://www.readbyqxmd.com/read/28252345/evidence-of-stress-in-%C3%AE-cells-obtained-with-laser-capture-microdissection-from-pancreases-of-brain-dead-donors
#9
Aref Ebrahimi, Min-Ho Jung, Jonathan M Dreyfuss, Hui Pan, Dennis Sgroi, Susan Bonner-Weir, Gordon C Weir
Isolated islets used for transplantation are known to be stressed, which can result from the circumstances of death, in particular brain death, the preservation of the pancreas with its warm and cold ischemia, from the trauma of the isolation process, and the complex events that occur during tissue culture. The current study focused upon the events that occur before the islet isolation procedure. Pancreases were obtained from brain dead donors (n = 7) with mean age 50 (11) and normal pancreatic tissue obtained at surgery done for pancreatic neoplasms (n = 7), mean age 69 (9)...
March 4, 2017: Islets
https://www.readbyqxmd.com/read/28241174/endoscopic-management-of-subglottic-stenosis
#10
Aaron J Feinstein, Alex Goel, Govind Raghavan, Jennifer Long, Dinesh K Chhetri, Gerald S Berke, Abie H Mendelsohn
Importance: Optimal management of subglottic stenosis has not been established. Endoscopic techniques include balloon dilation, radial incisions with carbon dioxide laser or cold knife, and combinations of techniques. Adjunctive measures include mitomycin application and glucocorticoid injection. Objective: To determine whether surgical technique or adjunctive measures are associated with duration between surgical procedures. Design, Setting, and Participants: Adult patients with subglottic stenosis treated endoscopically between 1995-2015 at a quaternary academic medical center were identified...
February 23, 2017: JAMA Otolaryngology—Head & Neck Surgery
https://www.readbyqxmd.com/read/28221028/characterization-of-an-airborne-laser-spark-ion-source-for-ambient-mass-spectrometry
#11
Andreas Bierstedt, Hendrik Kersten, Reto Glaus, Igor 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...
March 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28211726/realization-of-translational-symmetry-in-trapped-cold-ion-rings
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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)...
May 2017: Microvascular Research
https://www.readbyqxmd.com/read/28091517/unraveling-the-enhanced-oxygen-vacancy-formation-in-complex-oxides-during-annealing-and-growth
#19
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
#20
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
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