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phase coherence

Arixin Bo, Jose Alarco, Huaiyong Zhu, Eric R Waclawik, Haifei Zhan, YuanTong Gu
Construction of nano-architectures requires techniques like joint formation and trimming. For ceramic materials, however, it is extremely difficult to form nanojoints by conventional methods like merging. In this work, we demonstrate that ceramic titanate nanowires (NWs) can be joined by spot melting under electron beam (e-beam) irradiation (EBI). The irradiation fuses the contacted spot of titanate NWs yielding an intact nanojoint. Nanojoints with different morphologies can be produced. The joint structures consist of titanium dioxide (TiO2) rutile, anatase and titanate phases in direction away from the e-beam melting spot...
February 17, 2017: ACS Applied Materials & Interfaces
Hua Zhang, Jianhua Ma, Zhaoying Bian, Dong Zeng, Qianjin Feng, Wufan Chen
Four dimensional cone-beam computed tomography (4D-CBCT) has great potential clinical value because its ability to describe tumor and organ motion. But the challenge in 4D-CBCT reconstruction is the limited number of projections at each phase, which resulting in the reconstruction full of noise and streak artifacts with the conventional analytical algorithms. To address this problem, in this paper, we propose a motion compensated total variation regularization approach which tries to maximum explore the temporal coherence of the spatial structures among 4D-CBCT phases...
February 17, 2017: Physics in Medicine and Biology
Gemma Huguet, Xiangying Meng, John Rinzel
Phasic neurons typically fire only for a fast-rising input, say at the onset of a step current, but not for steady or slow inputs, a property associated with type III excitability. Phasic neurons can show extraordinary temporal precision for phase locking and coincidence detection. Exemplars are found in the auditory brain stem where precise timing is used in sound localization. Phasicness at the cellular level arises from a dynamic, voltage-gated, negative feedback that can be recruited subthreshold, preventing the neuron from reaching spike threshold if the voltage does not rise fast enough...
2017: Frontiers in Computational Neuroscience
J Pereda, F L Mota, L Chen, B Billia, D Tourret, Y Song, J-M Debierre, R Guérin, A Karma, R Trivedi, N Bergeon
We present a detailed analysis of oscillatory modes during three-dimensional cellular growth in a diffusive transport regime. We ground our analysis primarily on in situ observations of directional solidification experiments of a transparent succinonitrile 0.24wt% camphor alloy performed in microgravity conditions onboard the International Space Station. This study completes our previous reports [Bergeon et al., Phys. Rev. Lett. 110, 226102 (2013)10.1103/PhysRevLett.110.226102; Tourret et al., Phys. Rev. E 92, 042401 (2015)10...
January 2017: Physical Review. E
Armelle Cahuzac, Benjamin Wolff, Thibaud Mathis, Marie-Hélène Errera, José-Alain Sahel, Martine Mauget-Faÿsse
OBJECTIVE: To describe a new stage of multiple evanescent white dot syndrome (MEWDS), occurring at a very early phase of the disease. METHODS: Retrospective analysis of clinical, angiographic and tomographic findings in four patients with 'hyper-early' stage MEWDS. RESULTS: In four patients seen within 1 week of the onset of symptoms, fundus analysis revealed macular granity and the classic yellow-white dots, some having no corresponding hyperautofluorescent pattern...
February 15, 2017: British Journal of Ophthalmology
Peicheng Liao, Changjing Bao, Arne Kordts, Maxim Karpov, Martin H P Pfeiffer, Lin Zhang, Amirhossein Mohajerin-Ariaei, Yinwen Cao, Ahmed Almaiman, Morteza Ziyadi, Steven R Wilkinson, Moshe Tur, Tobias J Kippenberg, Alan E Willner
We experimentally investigate the dependence of Kerr comb generation, comb linewidth, and coherent system performance on the pump linewidth in a microresonator. We find that the generation of the primary comb can have a larger tolerance to the pump linewidth compared with that of the low-phase-noise comb. In addition, the linewidths of the generated combs are almost linearly dependent on the pump linewidth in the primary and low-phase-noise states. Furthermore, the optical signal-to-noise ratio penalty between the pump and generated Kerr combs in a coherent communication system is less than 0...
February 15, 2017: Optics Letters
Mohamed Alaasar, Marko Prehm, Silvio Poppe, Carsten Tschierske
Organic ferroelectrics are of growing importance for multifunctional materials. Here we provide an understanding of the distinct stages of the development of sterically induced polar order in liquid crystalline (LC) soft matter. Three series of weakly bent molecules derived from 4-cyanoresorcinol as the bent core unit with laterally fluorinated azobenzene wings have been synthesized and the effects of the position of fluorine substitution, alkyl chain length and temperature on the LC self-assembly and polar order were studied...
February 13, 2017: Chemistry: a European Journal
Jérôme Gateau, Hervé Rigneault, Marc Guillon
Intensity maxima and zeros of speckle patterns obtained behind a diffuser are experimentally interchanged by applying a spiral phase delay of charge ±1 to the impinging coherent beam. This transform arises from the expectation that tightly focused beams, which have a planar wave front around the focus, are so changed into vortex beams and vice versa. The statistics of extrema locations and the intensity distribution of the so-generated "complementary" patterns are characterized by numerical simulations. It is demonstrated experimentally that the incoherent superposition of the three "complementary speckle patterns" yield a synthetic speckle grain size enlarged by a factor of sqrt[3]...
January 27, 2017: Physical Review Letters
Maja Elstad, Ilias Zilakos, Tone Bergersen
OBJECTIVE: The acral skin contains arteriovenous anastomoses, which probably is the main part of skin microcirculation for blood flow adjustments and thermoregulation in the thermoneutral zone. The objective was to investigate if an increase in sympathetic activation during cooling influences the oscillatory pattern of acral skin blood flow. APPROACH: We had measurements of bilateral acral skin blood flow (n=12) during lowering of ambient temperature from 32°C to 18°C...
February 10, 2017: Physiological Measurement
Caspar E P van Munster, Bernard M J Uitdehaag
Due to the heterogeneous nature of the disease, it is a challenge to capture disease activity of multiple sclerosis (MS) in a reliable and valid way. Therefore, it can be difficult to assess the true efficacy of interventions in clinical trials. In phase III trials in MS, the traditionally used primary clinical outcome measures are the Expanded Disability Status Scale and the relapse rate. Secondary outcome measures in these trials are the number or volume of T2 hyperintense lesions and gadolinium-enhancing T1 lesions on magnetic resonance imaging (MRI) of the brain...
February 9, 2017: CNS Drugs
Alessandro Colombo, Davide Emilio Galli, Liberato De Caro, Francesco Scattarella, Elvio Carlino
Coherent Diffractive Imaging is a lensless technique that allows imaging of matter at a spatial resolution not limited by lens aberrations. This technique exploits the measured diffraction pattern of a coherent beam scattered by periodic and non-periodic objects to retrieve spatial information. The diffracted intensity, for weak-scattering objects, is proportional to the modulus of the Fourier Transform of the object scattering function. Any phase information, needed to retrieve its scattering function, has to be retrieved by means of suitable algorithms...
February 9, 2017: Scientific Reports
P Sibson, C Erven, M Godfrey, S Miki, T Yamashita, M Fujiwara, M Sasaki, H Terai, M G Tanner, C M Natarajan, R H Hadfield, J L O'Brien, M G Thompson
Improvement in secure transmission of information is an urgent need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and has rapidly grown from proof-of-concept to robust demonstrations and deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and large-scale deployment will likely require chip-based devices for improved performance, miniaturization and enhanced functionality. Here we report low error rate, GHz clocked QKD operation of an indium phosphide transmitter chip and a silicon oxynitride receiver chip-monolithically integrated devices using components and manufacturing processes from the telecommunications industry...
February 9, 2017: Nature Communications
Joseph Christakiran M, Philip James Thomas Reardon, Rocktotpal Konwarh, Jonathan C Knowles, Biman B Mandal
The anatomical complexity and slow regeneration capacity of hyaline cartilage at the osteochondral interface pose a great challenge in the repair of osteochondral defects (OCD). In this study, we utilized the processing feasibility offered by the sol derived 70S bioactive glass and silk fibroin (mulberry Bombyx mori and endemic Indian non-mulberry Antheraea assama), in fabricating a well-integrated, biomimetic scaffolding matrix with a coherent interface. Differences in surface properties such as wettability and amorphousness between the two silk groups resulted in profound variations in cell attachment and extracellular matrix protein deposition...
February 9, 2017: ACS Applied Materials & Interfaces
Lorenzo Monacelli, Giovanni Batignani, Giuseppe Fumero, Carino Ferrante, Shaul Mukamel, Tullio Scopigno
Photophysical and photochemical processes are often dominated by molecular vibrations in various electronic states. Dissecting the corresponding -often overlapping- spectroscopic signals from different electronic states is a challenge hampering their interpretation. Here we address impulsive stimulated Raman spectroscopy (ISRS), a powerful technique allowing to coherently stimulate and record Raman active modes using broadband pulses. Using a quantum-mechanical treatment of the ISRS process, we show the mode specific way the diverse components of the broadband probe contribute to the signal generated at a given wavelength...
February 8, 2017: Journal of Physical Chemistry Letters
Guohua Tao, Na Shen
Recently a coherence controlled (CC) approach to nonadiabatic dynamics was proposed by one of the authors based on the mapping between the decomposed classical state space and different types of nuclear dynamics. Here we elaborate the state-space decomposition scheme and the corresponding state-space-to-dynamics mapping of the CC approach in a general high-dimensional framework. In the CC formalism, dynamical properties such as the full electronic matrix can be evaluated by means of the ensemble of trajectories in the active state space, which consists of single-state domains and coherence domains...
February 20, 2017: Journal of Physical Chemistry. A
Alberto Mavilio, Dario Sisto, Paolo Ferreri, Nicola Cardascia, Giovanni Alessio
PURPOSE: A significant variability of the second harmonic (2ndH) phase of steady-state pattern electroretinogram (SS-PERG) in intrasession retest has been recently described in glaucoma patients (GP), which has not been found in healthy subjects. To evaluate the reliability of phase variability in retest (a procedure called RE-PERG or REPERG) in the presence of cataract, which is known to affect standard PERG, we tested this procedure in GP, normal controls (NC), and cataract patients (CP)...
2017: Clinical Ophthalmology
Sahand Babapoor-Farrokhran, Martin Vinck, Thilo Womelsdorf, Stefan Everling
The frontal eye fields (FEFs) and the anterior cingulate cortex (ACC) are commonly coactivated for cognitive saccade tasks, but whether this joined activation indexes coordinated activity underlying successful guidance of sensorimotor mapping is unknown. Here we test whether ACC and FEF circuits coordinate through phase synchronization of local field potential and neural spiking activity in macaque monkeys performing memory-guided and pro- and anti-saccades. We find that FEF and ACC showed prominent synchronization at a 3-9 Hz theta and a 12-30 Hz beta frequency band during the delay and preparation periods with a strong Granger-causal influence from ACC to FEF...
February 7, 2017: Nature Communications
P Fita, L Grill, A Listkowski, H Piwoński, S Gawinkowski, M Pszona, J Sepioł, E Mengesha, T Kumagai, J Waluk
We describe various experimental approaches that have been used to obtain a detailed understanding of double hydrogen transfer in porphycene, a model system for intramolecular hydrogen bonding and tautomerism. The emerging picture is that of a multidimensional tautomerization coordinate, with several vibrational modes acting as reaction-promoters or inhibitors through anharmonic intermode coupling. Tunnelling processes, coherent in the case of isolated molecules and incoherent in condensed phases, are found to play a major role even at elevated temperatures...
February 7, 2017: Physical Chemistry Chemical Physics: PCCP
Yao-Ping Xie, Xiao-Jie Zhang, Zhi-Pan Liu
Under mild static compression (15 GPa), graphite preferentially turns into hexagonal diamond, not cubic diamond, the selectivity of which is against thermodynamics. Here we, via novel potential energy surface global exploration, report seven types low energy intermediate structures at the atomic level that are key to the kinetics of graphite to diamond solid phase transition. On the basis of quantitative kinetics data, we show that hexagonal diamond has a facile initial nucleation mechanism inside graphite matrix and faster propagation kinetics owing to the presence of three coherent graphite/hexagonal diamond interfaces, forming coherent nuclei in graphite matrix...
February 9, 2017: Journal of the American Chemical Society
Jinyu Hu, Zuju Ma, Rongjian Sa, Yongfan Zhang, Kechen Wu
In recent years, a series of fluoride carbonate crystals, as second harmonic generation (SHG) materials, have been considerably developed; however the lead in these materials is a potential threat to the environment. In this study, the structure, mechanical and optical properties of ABCO3F (A = Rb, Cs; B = Ge, Sn) were systematically investigated to find alternatives to APbCO3F. We found that the RbSnCO3F crystal displays substantial stability and remarkable linear optical properties compared with those of the lead fluoride carbonate SHG materials...
February 6, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
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