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Akane Kurisu, Hisami Suga, Zdenek Prochazka, Kojiro Suzuki, Kazumasa Oguri, Tetsunori Inoue
We investigated a method for surviving tsunamis that involved the use of personal flotation devices (PFDs). In our work, we succeeded in numerically demonstrating that the heads of all the dummies wearing PFDs remained on the surface and were not dragged underwater after the artificial tsunami wave hit them. In contrast, the heads of all the dummies not wearing PFDs were drawn underwater immediately; these dummies were subsequently entrapped in a vortex. The results of our series of experiments are important as a first step to preventing the tragedies caused by tsunamis...
2018: PloS One
Ian K Bartol, Paul S Krueger, Carly A York, Joseph T Thompson
Squids, which swim using a coupled fin/jet system powered by muscular hydrostats, pose unique challenges for the study of locomotion. The high flexibility of the fins and complex flow fields generated by distinct propulsion systems require innovative techniques for locomotive assessment. For this study, we used proper orthogonal decomposition (POD) to decouple components of the fin motions and defocusing digital particle tracking velocimetry (DDPTV) to quantify the resultant 3D flow fields. Kinematic footage and DDPTV data were collected from brief squid Lolliguncula brevis [3...
May 22, 2018: Journal of Experimental Biology
Nichola Eliza Davies Calvani, Tina Cheng, Christine Green, Patrick Hughes, Emily Kwan, Elizabeth Maher, Russell David Bush, Jan Šlapeta
Commonly employed diagnostic methods for Fasciola spp., such as a traditional sedimentation and faecal egg count, or a commercially available coprological ELISA, have limitations in their sensitivity or ability to differentiate species. A reliable DNA isolation method coupled with real-time PCR addresses these issues by providing highly sensitive and quantitative molecular diagnosis from faecal samples. The current study evaluated a standard benchtop vortex for F. hepatica egg disruption in sheep and cattle faecal samples and determined the minimum faecal egg load required for a positive result from un-concentrated (raw) faecal samples...
May 22, 2018: Parasitology Research
Siddhartha Verma, Guido Novati, Petros Koumoutsakos
Fish in schooling formations navigate complex flow fields replete with mechanical energy in the vortex wakes of their companions. Their schooling behavior has been associated with evolutionary advantages including energy savings, yet the underlying physical mechanisms remain unknown. We show that fish can improve their sustained propulsive efficiency by placing themselves in appropriate locations in the wake of other swimmers and intercepting judiciously their shed vortices. This swimming strategy leads to collective energy savings and is revealed through a combination of high-fidelity flow simulations with a deep reinforcement learning (RL) algorithm...
May 21, 2018: Proceedings of the National Academy of Sciences of the United States of America
Reza Akramipour, Mohammad Reza Golpayegani, Simin Gheini, Nazir Fattahi
In this research, a new vortex assisted dispersive liquid-liquid microextraction based on the freezing of deep eutectic solvent (VADLLME-FDES) has been developed for the determination of organic mercury (R-Hg) and inorganic mercury (Hg2+ ) in blood samples prior to their analysis by graphite furnace atomic absorption spectrometry (GFAAS). In this method, a green solvent consisting of 1-octyl-3-methylimidazolium chloride and 1-undecanol was used as an extraction solvent, yielding the advantages of material stability, low density, and a suitable freezing point near room temperature...
August 15, 2018: Talanta
Emre Yavuz, Şerife Tokalıoğlu, Şaban Patat
In the present study, core-shell Fe3 O4 polydopamine nanoparticles were synthesized and used for the first time as an adsorbent for the vortex assisted magnetic dispersive solid phase extraction of copper from food samples. After elution, copper in the solutions was determined by FAAS. The adsorbent was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller surface area, and zeta potential measurements...
October 15, 2018: Food Chemistry
Umiko Ishizaki, Michinobu Nagao, Yumi Shiina, Kenji Fukushima, Tatsunori Takahashi, Yamato Shimomiya, Yuka Matsuo, Kei Inai, Shuji Sakai
BACKGROUND: Long-term hepatic dysfunction is an increasingly recognized complication of the Fontan operation for univentricular hearts. The purpose of this study was to determine whether Fontan-associated liver disease (FALD) could be predicted by flow dynamics in the right atrium (RA) of Fontan circulation.Methods and Results:Cardiac MRI and the serum levels of total bilirubin (TBil) and hyaluronic acid (HA) were analyzed in 36 patients who underwent an atriopulmonary connection type of Fontan operation...
May 18, 2018: Circulation Journal: Official Journal of the Japanese Circulation Society
Shahram Seidi, Mahshid Majd, Maryam Rezazadeh, Maryam Shanehsaz
A new Schiff base grafted graphene oxide-magnetic chitosan was utilized as a novel sorbent for extraction and quantification of lead ion in blood samples via dispersive magnetic solid phase extraction. The prepared nanocomposite sorbent was characterized by SEM, TEM, FT-IR, XRD, VSM and EDX and the quantification analysis was performed by microsampling flame atomic absorption spectrometry. The important parameters on the extraction efficiency were thoroughly optimized by means of experimental design. Under the optimized conditions, an aliquot of 50 mL of sample (pH 6...
May 17, 2018: Analytical Biochemistry
Byung Chul Choi, Kweon-Ha Park, Deog-Hee Doh
This paper presents a numerical study on the dispersing flammable limits with respect to the initial methane releases at TCH4,0  = -50 and -150 °C in the crosswind of ambient air according to the arrangement of (a) No Tank, (b) Tank I, (c) Tank II, and (d) Tank I and II on the ground. To provide a better physical insight on the dispersion behaviors of the methane releases, the spatial distributions of the quasi-averaged methane concentration and flow fields were mainly analyzed using 3-D large eddy simulations...
May 16, 2018: Journal of Hazardous Materials
Chuang Li, Lun-Hui Hu, Yi Zhou, Fu-Chun Zhang
Sau, Lutchyn, Tewari and Das Sarma (SLTD) proposed a heterostructure consisting of a semiconducting thin film sandwiched between an s-wave superconductor and a magnetic insulator and showed possible Majorana zero mode. Here we study spin polarization of the vortex core states and spin selective Andreev reflection at the vortex center of the SLTD model. In the topological phase, the differential conductance at the vortex center contributed from the Andreev reflection, is spin selective and has a quantized value [Formula: see text] at zero bias...
May 18, 2018: Scientific Reports
Minh Doan, J J Simons, Katherine Lilienthal, Tom Solomon, Kevin A Mitchell
We present experiments on one-way barriers that block reaction fronts in a fully three-dimensional (3D) fluid flow. Fluorescent Belousov-Zhabotinsky reaction fronts are imaged with laser-scanning in a laminar, overlapping vortex flow. The barriers are analyzed with a 3D extension to burning invariant manifold (BIM) theory that was previously applied to two-dimensional advection-reaction-diffusion processes. We discover tube and sheet barriers that guide the front evolution. The experimentally determined barriers are explained by BIMs calculated from a model of the flow...
March 2018: Physical Review. E
V O Nesterenko, A Repko, J Kvasil, P-G Reinhard
The low-energy dipole excitations in ^{24}Mg are investigated within the Skyrme quasiparticle random phase approximation for axial nuclei. The calculations with the force SLy6 reveal a remarkable feature: the lowest I^{π}K=1^{-}1 excitation (E=7.92  MeV) in ^{24}Mg is a vortical toroidal state (TS) representing a specific vortex-antivortex realization of the well-known spherical Hill's vortex in a strongly deformed axial confinement. This is a striking example of an individual TS which can be much more easily discriminated in experiment than the toroidal dipole resonance embracing many states...
May 4, 2018: Physical Review Letters
Chunlei Qu, Sandro Stringari
By applying a position-dependent detuning to a spin-orbit-coupled Hamiltonian with equal Rashba and Dresselhaus coupling, we exploit the behavior of the angular momentum of a harmonically trapped Bose-Einstein condensed atomic gas and discuss the distinctive role of its canonical and spin components. By developing the formalism of spinor hydrodynamics, we predict the precession of the dipole oscillation caused by the synthetic rotational field, in analogy with the precession of the Foucault pendulum, the excitation of the scissors mode, following the sudden switching off of the detuning, and the occurrence of Hall-like effects...
May 4, 2018: Physical Review Letters
Yiwen Zhang, Ang Chen, Wenzhe Liu, Chia Wei Hsu, Bo Wang, Fang Guan, Xiaohan Liu, Lei Shi, Ling Lu, Jian Zi
The vortex, a fundamental topological excitation featuring the in-plane winding of a vector field, is important in various areas such as fluid dynamics, liquid crystals, and superconductors. Although commonly existing in nature, vortices were observed exclusively in real space. Here, we experimentally observed momentum-space vortices as the winding of far-field polarization vectors in the first Brillouin zone of periodic plasmonic structures. Using homemade polarization-resolved momentum-space imaging spectroscopy, we mapped out the dispersion, lifetime, and polarization of all radiative states at the visible wavelengths...
May 4, 2018: Physical Review Letters
Wenshuai Gao, Liran Shi, Z W Ouyang, Zheng-Cai Xia, Zhe Wang, Bingjie Liu, Hexuan Li, Youming Zou, Lu Yu, Lei Zhang, Li Pi, Zhe Qu, Yuheng Zhang
The spin dynamics of the two-dimensional triangular-lattice antiferromagnet AgCrS2 is investigated by electron spin resonance (ESR) spectroscopy. The g-factor is found to show an unusual non-monotonously temperature dependent behavior, which, along with the super-Curie behavior observed in the ESR intensity data, provides clear evidences for the competition between FM and AFM fluctuations at temperatures well above TN. On approaching the Néel temperature TN from above, the linewidth is found to diverge. Such a divergent behavior could be well described by the Kawamura-Miyashita model due to Z2 type magnetic vortex-antivortex pairing, which is consistent with the expectation for a 2D Heisenberg magnetic system...
May 18, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Chester E Markwalter, Robert K Prud'homme
Flash NanoPrecipitation (FNP) is a scalable approach to generate polymeric nanoparticles using rapid micromixing in specially-designed geometries such as a confined impinging jets (CIJ) mixer or a Multi-Inlet Vortex Mixer (MIVM). A major limitation of formulation screening using the MIVM is that a single run requires tens of milligrams of the therapeutic. To overcome this, we have developed a scaled-down version of the MIVM, requiring as little as 0.2 mg of therapeutic, for formulation screening. The redesigned mixer can then be attached to pumps for scale-up of the identified formulation...
May 14, 2018: Journal of Pharmaceutical Sciences
Homa Naseri, Kieran Trickett, Nicholas Mitroglou, Ioannis Karathanassis, Phoevos Koukouvinis, Manolis Gavaises, Robert Barbour, Dale Diamond, Sarah E Rogers, Maurizio Santini, Jin Wang
We identify the physical mechanism through which newly developed quaternary ammonium salt (QAS) deposit control additives (DCAs) affect the rheological properties of cavitating turbulent flows, resulting in an increase in the volumetric efficiency of clean injectors fuelled with diesel or biodiesel fuels. Quaternary ammonium surfactants with appropriate counterions can be very effective in reducing the turbulent drag in aqueous solutions, however, less is known about the effect of such surfactants in oil-based solvents or in cavitating flow conditions...
May 16, 2018: Scientific Reports
Yun Liu, Jesse Roll, Stephen Van Kooten, Xinyan Deng
The aerodynamic force on flying insects results from the vortical flow structures that vary both spatially and temporally throughout flight. Due to these complexities and the inherent difficulties in studying flying insects in a natural setting, a complete picture of the vortical flow has been difficult to obtain experimentally. In this paper, Schlieren , a widely used technique for highspeed flow visualization, was adapted to capture the vortex structures around freely flying hawkmoth ( Manduca ). Flow features such as leading-edge vortex, trailing-edge vortex, as well as the full vortex system in the wake were visualized directly...
May 2018: Biology Letters
Van-Chien Bui, Thi-Huong Nguyen
Cations-induced DNA aggregation can modify the local structure of oligonucleotides and has potential applications in medicine and biotechnology. Here, we used atomic force microscopy to investigate λ-DNA aggregation on Mg2+ -treated glass (Mg2+ /glass) and in Mg2+ solution. Atomic force microscopy topography images showed that some DNA fragments were slightly stacked together on 10 mM Mg2+ /glass and stacked stronger on ≥50 mM Mg2+ /glass. They also showed that DNA aggregated stronger in Mg2+ solution than on Mg2+ /glass, ie, DNAs are strongly stacked and twisted at 10 mM Mg2+ , rolled together at 50 mM Mg2+ , and slightly aggregated to form small particles at 100 mM Mg2+ ...
May 15, 2018: Journal of Molecular Recognition: JMR
A Aadhi, Varun Sharma, G K Samanta
We report on a novel experimental scheme to generate continuous-wave (cw), high-power, and higher-order optical vortices tunable across a mid-IR wavelength range. Using a cw, two-crystal, singly resonant optical parametric oscillator (T-SRO) and pumping one of the crystals with a Gaussian beam and the other crystal with optical vortices of orders lp =1-6, we have directly transferred the vortices at near-IR to the mid-IR wavelength range. The idler vortices of orders li =1-6 are tunable across 2276-3576 nm with a maximum output power of 6...
May 15, 2018: Optics Letters
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