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Gonzalo Arranz, Manuel Moriche, Markus Uhlmann, Oscar Flores, Manuel García-Villalba
Numerical simulations of the auto-rotation of a model winged seed are presented. The calculations are performed by solving simultaneously the Navier-Stokes equations for the flow surrounding the seed and the rigid-body equations for the motion of the seed. The Reynolds number based on the descent speed and a characteristic chord length is varied in the range 80 - 240. Within this range, the seed attains an asymptotic state with finite amplitude auto-rotation, while for smaller values of the Reynolds number no auto-rotation is observed...
February 21, 2018: Bioinspiration & Biomimetics
Francesco Puosi, Noel Jakse, Alain Pasturel
As approaching the glass transition, particle motion in liquids becomes highly heterogeneous and regions with virtually no mobility coexist with liquid-like domains. This complex dynamics is believed to be responsible for different phenomena including non-exponential relaxation and the breakdown of Stokes-Einstein relation. Understanding the relationships between dynamical heterogeneities and local structure in metallic liquids and glasses is a major scientific challenge. Here we use classical molecular dynamics simulations to study the atomic dynamics and microscopic structure of Cu<sub>50</sub>Zr<sub>50</sub> alloy in the supercooling regime...
February 21, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Erika Kristina Lindstrøm, Jakob Schreiner, Geir Andre Ringstad, Victor Haughton, Per Kristian Eide, Kent-Andre Mardal
Background Investigators use phase-contrast magnetic resonance (PC-MR) and computational fluid dynamics (CFD) to assess cerebrospinal fluid dynamics. We compared qualitative and quantitative results from the two methods. Methods Four volunteers were imaged with a heavily T2-weighted volume gradient echo scan of the brain and cervical spine at 3T and with PC-MR. Velocities were calculated from PC-MR for each phase in the cardiac cycle. Mean pressure gradients in the PC-MR acquisition through the cardiac cycle were calculated with the Navier-Stokes equations...
January 1, 2018: Neuroradiology Journal
Alexis Torres-Carbajal, Ramón Castañeda-Priego
We report on the friction and diffusion of a single mobile nano-colloidal disk, whose size and mass are one and two orders of magnitude, respectively, greater than the molecules of the host solvent; all particles are restricted to move in a two-dimensional space. Using molecular dynamics simulations, the variation of the transport coefficients as a function of the thermodynamic state of the supporting fluid, in particular, around those states in the neighbourhood of the liquid-liquid phase coexistence, is investigated...
February 21, 2018: Physical Chemistry Chemical Physics: PCCP
Alexander E Khudozhitkov, Peter Stange, Anne-Marie Bonsa, Viviane Overbeck, Andreas Appelhagen, Alexander G Stepanov, Daniil I Kolokolov, Dietmar Paschek, Ralf Ludwig
The heterogeneity in dynamics has important consequences for understanding the viscosity, diffusion, ionic mobility, and the rates of chemical reactions in technology relevant systems such as polymers, metallic glasses, aqueous solutions, and inorganic materials. Herein, we study the spatial and dynamic heterogeneities in ionic liquids by means of solid state NMR spectroscopy. In the2 H spectra of the protic ionic liquid [TEA][OTf] we observe anisotropic and isotropic signals at the same time. The spectra measured below the melting temperature at 306 K could be simulated by a superposition of the solid and liquid line shapes, which provided the transition enthalpies between the rigid and mobile fractions...
February 21, 2018: Chemical Communications: Chem Comm
Debra A Schaumberg, Laura McDonald, Surbhi Shah, Michael Stokes, Beth L Nordstrom, Sreeram V Ramagopalan
Comparative effectiveness research (CER) guidelines have been developed to direct the field toward the most rigorous study methodologies. A challenge, however, is how to ensure the best evidence is generated, and how to translate methodologically complex or nuanced CER findings into usable medical evidence. To reach that goal, it is important that both researchers and end users of CER output become knowledgeable about the elements that impact the quality and interpretability of CER. This paper distilled guidance on CER into a practical tool to assist both researchers and nonexperts with the critical review and interpretation of CER, with a focus on issues particularly relevant to CER in oncology...
February 21, 2018: Journal of Comparative Effectiveness Research
Matthew D Smith, Hemamala I Karunadasa
With nearly 20% of global electricity consumed by lighting, more efficient illumination sources can enable massive energy savings. However, effectively creating the high-quality white light required for indoor illumination remains a challenge. To accurately represent color, the illumination source must provide photons with all the energies visible to our eye. Such a broad emission is difficult to achieve from a single material. In commercial white-light sources, one or more light-emitting diodes, coated by one or more phosphors, yield a combined emission that appears white...
February 20, 2018: Accounts of Chemical Research
Jessica B Stokes-Parish, Robbert Duvivier, Brian Jolly
BACKGROUND: Simulation Based Education (SBE) is used as a primer for clinical education in nursing and other health professions. Participant engagement strategies and good debriefing have been identified as key for effective simulations. The environment in which the simulation is situated also plays a large role in the degree of participant engagement. Various cues are staged within simulations to enhance this engagement process. Moulage techniques are used in current-day simulation to mimic illnesses and wounds, acting as visual and tactile cues for the learner...
February 15, 2018: Nurse Education Today
Yuan Liu, Jialiang Gao, Min Peng, Hongyan Meng, Hongbo Ma, Pingping Cai, Yuan Xu, Qiong Zhao, Guomin Si
Rhizoma Gastrodiae (also known as Tian ma ), the dried rhizome of Gastrodia elata Blume, is a famous Chinese herb that has been traditionally used for the treatment of headache, dizziness, spasm, epilepsy, stoke, amnesia and other disorders for centuries. Gastrodin, a phenolic glycoside, is the main bioactive constituent of Rhizoma Gastrodiae . Since identified in 1978, gastrodin has been extensively investigated on its pharmacological properties. In this article, we reviewed the central nervous system (CNS) effects of gastrodin in preclinical models of CNS disorders including epilepsy, Alzheimer's disease, Parkinson's disease, affective disorders, cerebral ischemia/reperfusion, cognitive impairment as well as the underlying mechanisms involved and, where possible, clinical data that support the pharmacological activities...
2018: Frontiers in Pharmacology
Amir Muhammad, Mohammad Younas, Mashallah Rezakazemi
This study presents computational fluid dynamics (CFD) simulation of dispersion-free liquid-liquid extraction of copper(II) with trifluoroacetylacetone (TFA) in hollow fiber membrane contactor (HFMC). Mass and momentum balance Navier-Stokes equations were coupled to address the transport of copper(II) solute across membrane contactor. Model equations were simulated using COMSOL Multiphysics™. The simulation was run to study the detailed concentration distribution of copper(II) and to investigate the effects of various parameters like membrane characteristics, partition coefficient, and flow configuration on extraction efficiency...
January 27, 2018: Environmental Science and Pollution Research International
Charlotte M A Farrow, Geoffrey R Akien, Nathan R Halcovitch, James A Platts, M P Coogan
2,6-Bis(2-quinolyl)-4(1H)-pyridone 1, a novel quinoline analogue of the well-known ligand 2-terpyridone, shows unusual fluorescence with a large Stokes shift and low energy emission. Pyridine-pyridone tautomerism is investigated by NMR and theoretical methods and indicates that the low energy emission is from the pyridine form. 1 reacts with Ag(i) salts to give a double helical Ag 2 N 6 core showing a BLUE shift in fluorescence with respect to the free ligand, which has been characterised experimentally and theoretically as involving an unusual mixed MLCT/ILCT excited state and emission from a singlet state...
February 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Wei Huang, Shuaidan Huang, Ming Zhang, Yancong Chen, Gui-Lin Zhuang, Yao Li, Ming-Liang Tong, Juan Yong, Yujie Li, Dayu Wu
Magnetic cooling is a highly efficient refrigeration technique with the potential of replacing expensive and rare helium-3 in the field of ultra-low temperature cooling. However, the visualization of a cryogen at an extremely low temperature and in a strong magnetic field is challenging, but it is crucial for the precise positioning and in situ thermal probe measurements in potential practical applications. Here, the activation of a red-emissive Mn(ii) ion using 3d/4f chemistry produces a luminescent molecule cooler, [Gd 5 Mn 2 (L OMe ) 2 (OH) 4 (Ac) 6 (MeOH) 10 Cl 2 ]Cl 3 ·2MeOH (1), with the core of an Mn(ii)-anchored heptanuclear [GdMn] pyramid...
February 16, 2018: Chemical Communications: Chem Comm
Antonio Olmedilla, Miha Založnik, Bernard Rouat, Hervé Combeau
The packing of free-floating crystal grains during solidification has a strong impact on the phase-change process as well as on the structure and the defects in the solidified material. The packing fraction is affected by the particular dendritic morphology of the grains and by their low inertia resulting from the small density difference between solid and liquid. Understanding the grain packing phenomenon during metal alloy solidification is not experimentally possible since packing is coupled to many other phenomena...
January 2018: Physical Review. E
R C Hidalgo, A Goñi-Arana, A Hernández-Puerta, I Pagonabarraga
In this work, we numerically study a dense colloidal suspension flowing through a small outlet driven by a pressure drop using lattice-Boltzmann methods. This system shows intermittent flow regimes that precede clogging events. Several pieces of evidence suggest that the temperature controls the dynamic state of the system when the driving force and the aperture size are fixed. When the temperature is low, the suspension's flow can be interrupted during long time periods, which can be even two orders of magnitude larger than the system's characteristic time (Stokes)...
January 2018: Physical Review. E
Luca Bolzonello, Annalisa Polo, Andrea Volpato, Elena Meneghin, Massimiliano Cordaro, Mariachiara Trapani, Mariagrazia Fortino, Alfonso Pedone, Maria Angela Castriciano, Elisabetta Collini
In this work, we demonstrate the use of 2D electronic spectroscopy (2DES) to study the mechanism and the timescale of the femtosecond Stokes shift dynamics in molecules characterized by intra-molecular charge transfer, such as distyryl-functionalized BODIPY molecules. The obtained results demonstrate that 2DES allows clear and direct visualization of the phenomenon. The analysis of the 2D data in terms of 2D frequency-frequency decay associated maps provides indeed not only the timescale of the relaxation process but also the starting and the final point of the energy flow and the associated reorganization energy, identifiable looking at the coordinates of a negative signature below diagonal...
February 15, 2018: Journal of Physical Chemistry Letters
Hossein Roohi, Parvaneh Alizadeh
Near-infrared (NIR) fluorescent dyes have recently gained special attention due to their applications to use as molecular probes for imaging of biological targets and sensitive determination. In this study, photophysical properties of the 7-hydroxy-1-indanone based fluorophors A1, A2, A3, B1, B2 and 3R-B2 (R=CF3, NH2, NO2and OMe) in the gas and three solution phases were probed using TD-DFT method at PBE0/6-311++G(d,p) and M06-2X/6-311++G(d,p) levels of theory. In addition to structural and photophysical properties as well as ESIPT mechanism of all mentioned molecules, the FC and relaxed potential energy surfaces of B2 and 3R-B2 (R=CF3and NH2) molecules were explored in gas phase and acetonitrile, cyclohexane and water solvents...
February 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Hongshui Lv, Haiyan Sun, Shoujuan Wang, Fangong Kong
A novel dicyanoisophorone based fluorescent probe HP was developed to detect hydrazine. Upon the addition of hydrazine, probe HP displayed turn-on fluorescence in the red region with a large Stokes shift (180nm). This probe exhibited high selectivity and high sensitivity to hydrazine in solution. The detection limit of HP was found to be 3.26ppb, which was lower than the threshold limit value set by USEPA (10ppb). Moreover, the probe was successfully applied to detect hydrazine in different water samples and living cells...
February 8, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yariv Shamir, Yaakov Glick, Matitya Aviel, Avital Attias, Shaul Pearl
We report a strictly all-fiber clad pumped Raman fiber laser with a CW power of 250 W. To the best of our knowledge, this is the highest power Raman fiber laser demonstrated in any configuration allowing brightness enhancement. In addition, this is the first report of a Raman clad pumped all-fiber laser. The brightness of the pump source was enhanced by a factor of ∼3.8. This result was achieved by the design of a novel triple-clad fiber, with tight pump power inner confining clad that both maximized the Raman gain and inhibited the second Stokes radiation...
February 15, 2018: Optics Letters
Victoria K Woodcock, Sally Clive, Richard H Wilson, Vicky M Coyle, Michael R L Stratford, Lisa K Folkes, Richard Eastell, Claire Barton, Paul Jones, Shamim Kazmi-Stokes, Helen Turner, Sarah Halford, Adrian L Harris, Mark R Middleton
BACKGROUND: Src is involved in cancer invasion and metastasis. AZD0424, an oral inhibitor of Src and ABL1, has shown evidence of anti-tumour activity in pre-clinical studies. METHODS: A phase Ia, dose escalation study was performed to assess the safety of continuous oral dosing with AZD0424 in advanced solid tumours. Secondary objectives included investigation of AZD0424 pharmacokinetics, effect on Src activity using markers of bone turnover, and anti-tumour activity...
February 13, 2018: British Journal of Cancer
Yu Huang, Xian Zhang, Emilie Ringe, Lingwei Ma, Xiang Zhai, Lingling Wang, Zhengjun Zhang
Depending on the experimental conditions and plasmonic systems, the correlations between near-field surface enhanced Raman scattering (SERS) behaviors and far-field localized surface plasmon resonance (LSPR) responses have sometimes been accepted directly or argued or explored. In this work, we focus on the attractive subwavelength closely spaced metallic nanorod arrays and investigate in detail the complex relationship between their SERS behaviors and plasmon resonances. This is achieved utilizing a combination of array fabrication, conventional LSPR spectra, SERS measurements, electron microscopy and numerical modeling...
February 13, 2018: Nanoscale
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