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Thomas Eisenstecken, Gerhard Gompper, Roland G Winkler
The intramolecular dynamics of flexible and semiflexible polymers in response to active noise is studied theoretically. The active noise may either originate from interactions of a passive polymer with a bath of active Brownian particles or the polymer itself is comprised of active Brownian particles. We describe the polymer by the continuous Gaussian semiflexible-polymer model, taking into account the finite polymer extensibility. Our analytical calculations predict a strong dependence of the polymer dynamics on the activity...
April 21, 2017: Journal of Chemical Physics
Kelly M M Berghuis, John G Semmler, George M Opie, Aylin K Post, Tibor Hortobágyi
It is unclear how old age affects the neuronal mechanisms of motor learning. We reviewed the neuronal mechanisms of how healthy old and young adults acquire motor skills as assessed with transcranial magnetic stimulation. Quantitative meta-analyses of 11 studies, involving ballistic and visuomotor tasks performed by upper extremity muscles in 132 healthy old and 128 young adults, revealed that the motor practice-induced increase in corticospinal excitability (CSE) is task-dependent but not age-dependent, with an increase in CSE in both age groups after visuomotor but not ballistic training...
March 27, 2017: Neurobiology of Aging
Mitali Banerjee, Moty Heiblum, Amir Rosenblatt, Yuval Oreg, Dima E Feldman, Ady Stern, Vladimir Umansky
The quantum of thermal conductance of ballistic (collisionless) one-dimensional channels is a unique fundamental constant. Although the quantization of the electrical conductance of one-dimensional ballistic conductors has long been experimentally established, demonstrating the quantization of thermal conductance has been challenging as it necessitated an accurate measurement of very small temperature increase. It has been accomplished for weakly interacting systems of phonons, photons and electronic Fermi liquids; however, it should theoretically also hold in strongly interacting systems, such as those in which the fractional quantum Hall effect is observed...
April 17, 2017: Nature
Anna M Shih, Leah Mendelson, Alexandra H Techet
Smallscale archer fish, Toxotes microlepis, are best known for spitting jets of water to capture prey, but also hunt by jumping out of the water to heights of up to 2.5 body lengths. In this study, high-speed imaging and particle image velocimetry were used to characterize the kinematics and hydrodynamics of this jumping behavior. Jumping used a set of kinematics distinct from those of in-water feeding strikes and was segmented into three phases: (1) hovering to sight prey at the surface, (2) rapid upward thrust production and (3) gliding to the prey once out of the water...
April 15, 2017: Journal of Experimental Biology
Takaki Yamamoto, Masaki Sano
We report the first experimental realization of a chiral artificial microswimmer exhibiting helical motion without any external fields. We discovered that a cholesteric liquid crystal (CLC) droplet with a helical director field swims in a helical path driven by the Marangoni flow in an aqueous surfactant solution. We also showed that the handedness of the helical path is reversed when that of the CLC droplet is reversed by replacing the chiral dopant with the enantiomer. In contrast, nematic liquid crystal (NLC) droplets exhibited ballistic motions...
April 19, 2017: Soft Matter
Debarshee Bagchi
We study the thermal transport properties of the one-dimensional Fermi-Pasta-Ulam model (β type) with long-range interactions. The strength of the long-range interaction decreases with the (shortest) distance between the lattice sites as distance^{-δ}, where δ≥0. Two Langevin heat baths at unequal temperatures are connected to the ends of the one-dimensional lattice via short-range harmonic interactions that drive the system away from thermal equilibrium. In the nonequilibrium steady state the heat current, thermal conductivity, and temperature profiles are computed by solving the equations of motion numerically...
March 2017: Physical Review. E
Jia-Ming Zhang, Jing-Dong Bao
We study a frequency-dependent damping model of hyperdiffusion within the generalized Langevin equation. The model allows for the colored noise defined by its spectral density, assumed to be proportional to ω^{δ-1} at low frequencies with 0<δ<1 (sub-Ohmic damping) or 1<δ<2 (super-Ohmic damping), where the frequency-dependent damping is deduced from the noise by means of the fluctuation-dissipation theorem. It is shown that for super-Ohmic damping and certain parameters, the diffusive process of the particle in a titled periodic potential undergos sequentially four time regimes: thermalization, hyperdiffusion, collapse, and asymptotical restoration...
March 2017: Physical Review. E
S A Bolliger, S A Poschmann, M J Thali, S Eggert
PURPOSE: Today, synthetic models have all but replaced animal and corpse models in examining damage to soft-tissues and skeletal structures by ballistic trauma. As, however, non-solid organs such as the lungs, have not been able to be replaced by a fully synthetic model we attempted to create such a model. MATERIAL AND METHODS: 20% ordnance gelatine was frothed with a household mixer and cooled to stable foam. Several of these foam blocks were then stuck together with liquid gelatine and placed between 10% gelatine blocks...
April 4, 2017: Forensic Science International
Ahmad Zubair, Amirhasan Nourbakhsh, Jing Yong Hong, Meng Qi, Yi Song, Debdeep Jena, Jing Kong, Mildred S Dresselhaus, Tomas Palacios
Single layer graphene is an ideal material for the base layer of hot electron transistors (HETs) for potential THz applications. The ultra-thin body and exceptionally long mean free path maximizes the probability for ballistic transport across the base of the HET. We demonstrate, for the first time, the operation of a high performance HET using a graphene/WSe2 van der Waals (vdW) heterostructure as a base-collector barrier. The resulting device, with a GaN/AlN heterojunction as emitter, exhibits a current density of 50 A/cm2, DC current gain above 3 and 75% injection efficiency, which are record values among graphene-base HETs...
April 17, 2017: Nano Letters
Anne-Sophie Wozny, Alexandra Lauret, Priscillia Battiston-Montagne, Jean-Baptiste Guy, Michael Beuve, Micaela Cunha, Yannick Saintigny, Emilie Blond, Nicolas Magne, Philippe Lalle, Dominique Ardail, Gersende Alphonse, Claire Rodriguez-Lafrasse
BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) are resistant to standard treatments, partly due to cancer stem cells (CSCs) localised in hypoxic niches. Compared to X-rays, carbon ion irradiation relies on better ballistic properties, higher relative biological effectiveness and the absence of oxygen effect. Hypoxia-inducible factor-1α (HIF-1α) is involved in the resistance to photons, whereas its role in response to carbon ions remains unclear. METHODS: Two HNSCC cell lines and their CSC sub-population were studied in response to photons or carbon ion irradiation, in normoxia or hypoxia, after inhibition or not of HIF-1α...
April 13, 2017: British Journal of Cancer
V A Fetisov, I Yu Makarov, A A Gusarov, A S Lorents, S A Smirenin, V B Stragis
The study of blood stains retained at the scene of the crime is of crucial importance for the preliminary inquiry. The present article is focused on the analysis of the possibilities and prospects for the use of photogrammetry (PM) as exemplified by the foreign expert practice of the blood stains examination at the site of the event. It is shown that the results of the application of digital photogrammetry in addition to the traditional methods of morphological investigations enables the forensic medical experts to reconstruct a number of unique features and circumstances that accompanied the commission of a crime at the site of the event...
2017: Sudebno-meditsinskaia Ekspertiza
Kamil Bobowski, Markus Gleich, Niko Pontius, Christian Schuessler-Langeheine, Christoph Trabant, Marko Wietstruk, Björn Frietsch, Martin Weinelt
We studied the magnetization dynamics of gadolinium metal after femtosecond laser excitation recording the X-ray magnetic circular dichroism in reflection (XMCD-R) at the Gd $M_5$ absorption edge. Varying the photon energy of the pump pulse allows us to change the initial energy distribution of photoexcited carriers. The overall similar response for excitation with 0.95, 1.55 and 3.10\,eV photons at comparable pump fluences indicates that ultrafast ballistic carrier transport leads to a homogeneous energy distribution on the femtosecond timescale in the probed sample volume...
April 11, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Mohamed Frikha, Mohammad S Derbel, Nesrine Chaâri, Adnene Gharbi, Karim Chamari
The aim of the study was to compare the effect of stretching procedures on global coordination and accuracy in instep soccer kicks achieved in different stress conditions. Twenty male young soccer players completed the global coordination test (GC), the instep kicking accuracy test in free (FKA) and in time-pressure (TPKA) conditions, either after static (SS), dynamic (DS), ballistic (BS) or no-stretching (CTR) protocols, on nonconsecutive days and in a randomized order. After performing a 5min standardized intensity jogging (70% of MAV), followed by stretching exercises for 10min, each participant completed, successively, the GC, FKA and TPKA tests...
April 7, 2017: Human Movement Science
Ching-Hao Chang, Carmine Ortix
Snake orbits are trajectories of charge carriers curving back and forth which form at an interface where either the magnetic field direction or the charge carrier type are inverted. In ballistic samples their presence is manifested in the appearance of magnetoconductance oscillations at small magnetic fields. Here we show that signatures of snake orbits can also be found in the opposite diffusive transport regime. We illustrate this by studying the classical magnetotransport properties of carbon tubular structures subject to relatively weak transversal magnetic fields where snake trajectories appear in close proximity to the zero radial field projections...
April 10, 2017: Nano Letters
Ben Sidaway, Matthew Bouchard, Julie Chasse, Jonathan Dunn, Andrea Govoni, Breanne McPherson, Katherine Roy, David I Anderson
PURPOSE: The requirement for postural stability during the performance of motor skills has been clearly demonstrated in infants, but the necessity for such a postural substrate is not well documented in adults. The present study investigated the role of postural stability during a ballistic ball-kicking task in adults by providing varying degrees of external postural support. METHOD: In the 1st experiment, 30 participants performed 20 maximal-velocity kicks under each of 3 conditions: grasping a rigid stable handle, light fingertip touch, and grasping a suspended elastic tube...
April 7, 2017: Research Quarterly for Exercise and Sport
Luke Strickland, Andrew Heathcote, Roger W Remington, Shayne Loft
Event-based prospective memory (PM) tasks require participants to substitute an atypical PM response for an ongoing task response when presented with PM targets. Responses to ongoing tasks are often slower with the addition of PM demands ("PM costs"). Prominent PM theories attribute costs to capacity-sharing between the ongoing and PM tasks, which reduces the rate of processing of the ongoing task. We modeled PM costs using the Linear Ballistic Accumulator and the Diffusion Decision Model in a lexical-decision task with nonfocal PM targets defined by semantic categories...
April 6, 2017: Journal of Experimental Psychology. Learning, Memory, and Cognition
Sindhu K Madathil, Ying Deng-Bryant, Bernard S Wilfred, Lai Yee Leung, Janice S Gilsdorf, Deborah A Shear
BACKGROUND: Brain derived neurotrophic factor (BDNF) and Insulin-like growth factor-1 (IGF-1) are essential for neuroplasticity and neuronal survival. Despite the importance of these endogenous factors in mediating post-traumatic recovery, little is known about their response after penetrating type traumatic brain injury (TBI). The objective of this study was to quantify the expression levels BDNF and IGF-1, two well-known neuroplasticity mediators, following penetrating ballistic-like brain injury (PBBI)...
April 5, 2017: Journal of Trauma and Acute Care Surgery
Omer Tzang, Eyal Niv, Antonio M Caravaca-Aguirre, Rafael Piestun
Focusing inside scattering media is a challenging task with a variety of applications in biomedicine. State of the art methods mostly require invasive feedback inside or behind the sample, limiting practical use. We present a technique for dynamic control and focusing inside scattering media that combines two powerful methods: optical coherence tomography (OCT) and wave-front shaping (WFS). We use OCT as a non-invasive feedback for WFS optimization of a separate, penetrating laser. Energy absorbed in the sample, creates thermal expansions that are used for the feedback mechanism...
March 20, 2017: Optics Express
J Dufouleur, L Veyrat, B Dassonneville, E Xypakis, J H Bardarson, C Nowka, S Hampel, J Schumann, B Eichler, O G Schmidt, B Büchner, R Giraud
Disorder remains a key limitation in the search for robust signatures of topological superconductivity in condensed matter. Whereas clean semiconducting quantum wires gave promising results discussed in terms of Majorana bound states, disorder makes the interpretation more complex. Quantum wires of 3D topological insulators offer a serious alternative due to their perfectly-transmitted mode. An important aspect to consider is the mixing of quasi-1D surface modes due to the strong degree of disorder typical for such materials...
April 4, 2017: Scientific Reports
Daniel Santos, Felipe Pinheiro, Julian Velev, Mairbek Chshiev, Claudine Lacroix, J d'Albuquerque E Castro
We have investigated the electronic transport and the anisotropic magnetoresistance in systems consisting of pairs of antiferromagnetically aligned layers separated by a non-magnetic layer, across which an antiferromagnetic coupling between the double layers is established. Calculations have been performed within the framework of the tight-binding model, taking into account the exchange coupling within the ferromagnetic layers and the Rashba spin-orbit interaction. Conductivities have been evaluated in the ballistic regime, based on Kubo formula...
April 4, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
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