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Hop kinetic

Rachel H Gilmore, Elizabeth M Y Lee, Mark C Weidman, Adam P Willard, William A Tisdale
Energetic disorder in quantum dot solids adversely impacts charge carrier transport in quantum dot solar cells and electronic devices. Here, we use ultrafast transient absorption spectroscopy to show that homogeneously broadened PbS quantum dot arrays (σhom(2):σinh(2)>19:1, σinh/kBT<0.4) can be realized if quantum dot batches are sufficiently monodisperse (δ ≲ 3.3%). Homogeneous linewidth is found to be an inverse function of quantum dot size, monotonically increasing from ~25 meV for the largest quantum dots (5...
January 19, 2017: Nano Letters
Marcin M Wysokiński, Jan Kaczmarczyk
We investigate the effect of the electron-hole (e-h) symmetry breaking on d-wave superconductivity induced by non-local effects of correlations in the generalized Hubbard model. The symmetry breaking is introduced in a two-fold manner: by the next-to-nearest neighbor hopping of electrons and by the charge-bond interaction-the off-diagonal term of the Coulomb potential. Both terms lead to a pronounced asymmetry of the superconducting order parameter. The next-to-nearest neighbor hopping enhances superconductivity for h-doping, while diminishes it for e-doping...
January 16, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Manjusha Chugh, Madhav Ranganathan
Studying the adsorbate interactions on a surface helps in understanding the growing surface morphologies and calculating the effective surface diffusion barriers. We study the interaction between Ga-Ga, N-N and Ga-N adatom pairs on the polar GaN(0001) surface using ab initio calculations based on density functional theory. The interaction energy between two adatoms on the surface does not seem to follow definite trends with increasing distance between the adatoms. The presence of a number of possible reconstructions on clean GaN(0001) and periodic effects due to the finite size complicate the analysis of the interactions...
January 18, 2017: Physical Chemistry Chemical Physics: PCCP
Young Ki Lee, Talid Sinno
The lattice kinetic Monte Carlo (LKMC) method is studied in the context of Brownian particles subjected to drift forces, here principally represented by external fluid flow. LKMC rate expressions for particle hopping are derived that satisfy detailed balance at equilibrium while also providing correct dynamical trajectories in advective-diffusive situations. Error analyses are performed for systems in which collections of particles undergo Brownian motion while also being advected by plug and parabolic flows...
December 21, 2016: Journal of Chemical Physics
Carlos Franco, Paula Mayorga Burrezo, Vega Lloveras, Rubén Caballero, Isaac Alcón, Stefan T Bromley, Marta Mas-Torrent, Fernando Langa, Juan T López Navarrete, Concepciò Rovira, Juan Casado, Jaume Veciana
Charge transfer/transport in molecular wires over varying distances is a subject of great interest. The feasible transport mechanisms have been generally accounted for on the basis of tunneling or superexchange charge transfer operating over small distances which progressively gives way to hopping transport over larger distances. The underlying molecular sequential steps that likely take place during hopping and the operative mechanism occurring at intermediate distances have received much less attention given the difficulty in assessing detailed molecular-level information...
January 18, 2017: Journal of the American Chemical Society
Akihiro Okamoto, Yoshihide Tokunou, Junki Saito
Outer-membrane c-type cytochrome (OM c-Cyt) complexes in several genera of iron-reducing bacteria, such as Shewanella and Geobacter, are capable of transporting electrons from the cell interior to extracellular solids as a terminal step of anaerobic respiration. The kinetics of this electron transport has implications for controlling the rate of microbial electron transport during bioenergy or biochemical production, iron corrosion, and natural mineral cycling. Herein, we review the findings from in-vivo and in-vitro studies examining electron transport kinetics through single OM c-Cyt complexes in Shewanella oneidensis MR-1...
2016: Biophysics and Physicobiology
Glenn S Fleisig, Alek Z Diffendaffer, Kyle T Aune, Brett Ivey, Walter A Laughlin
BACKGROUND: Weighted-ball throwing programs are commonly used in training baseball pitchers to increase ball velocity. The purpose of this study was to compare kinematics and kinetics among weighted-ball exercises with values from standard pitching (ie, pitching standard 5-oz baseballs from a mound). HYPOTHESIS: Ball and arm velocities would be greater with lighter balls and joint kinetics would be greater with heavier balls. STUDY DESIGN: Controlled laboratory study...
November 21, 2016: Sports Health
Beom Hyun Kim, Tomonori Shirakawa, Seiji Yunoki
The t_{2g} orbitals of an edge-shared transition-metal oxide with a honeycomb lattice structure form dispersionless electronic bands when only hopping mediated by the edge-sharing oxygens is accessible. This is due to the formation of isolated quasimolecular orbitals (QMOs) in each hexagon, introduced recently by Mazin et al. [Phys. Rev. Lett. 109, 197201 (2012)], which stabilizes a band insulating phase for t_{2g}^{5} systems. However, with the help of the exact diagonalization method to treat the electron kinetics and correlations on an equal footing, we find that the QMOs are fragile against not only the spin-orbit coupling (SOC) but also the Coulomb repulsion...
October 28, 2016: Physical Review Letters
Hiromitsu Itoh, Kohei Takiguchi, Yohei Shibata, Satoshi Okubo, Shinichi Yoshiya, Ryosuke Kuroda
[Purpose] Kinematic and kinetic characteristics of the limb during side-hopping and hip/knee interaction during this motion have not been clarified. The purposes of this study were to examine the biomechanical parameters of the knee during side hop and analyze its relationship with clinical measurements of hip function. [Subjects and Methods] Eleven male college rugby players were included. A three-dimensional motion analysis system was used to assess motion characteristics of the knee during side hop. In addition, hip range of motion and muscle strength were evaluated...
September 2016: Journal of Physical Therapy Science
Bernard X W Liew, Susan Morris, Justin W L Keogh, Brendyn Appleby, Kevin Netto
BACKGROUND: In recent years, athletes have ventured into ultra-endurance and adventure racing events, which tests their ability to race, navigate, and survive. These events often require race participants to carry some form of load, to bear equipment for navigation and survival purposes. Previous studies have reported specific alterations in biomechanics when running with load which potentially influence running performance and injury risk. We hypothesize that a biomechanically informed neuromuscular training program would optimize running mechanics during load carriage to a greater extent than a generic strength training program...
October 22, 2016: BMC Musculoskeletal Disorders
Stephen P Bird, William J Markwick
BACKGROUND AND PURPOSE: Youth participation in basketball is on the rise, with basketball one of the top five participation sports in Australia. With increased participation there is a need for greater awareness of the importance of the pre-participation examination, including musculoskeletal screening and functional performance testing as part of a multidisciplinary approach to reducing the risk for future injuries. As majority of all basketball injuries affect the lower extremities, pre-participation musculoskeletal screening and functional performance testing should assess fundamental movement qualities throughout the kinetic chain with an emphasis on lower extremity force characteristics, specifically eccentric loading tasks...
October 2016: International Journal of Sports Physical Therapy
Dana Krepel, David Gomez, Stefan Klumpp, Yaakov Levy
The key feature explaining the rapid recognition by a protein of its DNA target site lies in the combination of one- and three-dimensional (1D and 3D) diffusion, which allows efficient scanning of the many alternative sites. This facilitated diffusion mechanism is expected to be affected by cellular conditions, particularly crowding, given that up to 40% of the total cellular volume may by occupied by macromolecules. Using coarse-grained molecular dynamics and Monte-Carlo simulations, we show that the crowding particles can enhance facilitated diffusion and accelerate search kinetics...
October 10, 2016: Journal of Physical Chemistry. B
Jordan C Vincent, Mikko Muuronen, Kirk C Pearce, Luke N Mohanam, Enrico Tapavicza, Filipp Furche
The effect of non-adiabatic transitions on branching ratios, kinetic and internal energy distribution of fragments, and reaction mechanisms observed in acetadehyde photodissociation is investigated by non-adiabatic molecular dynamics (NAMD) simulations using time-dependent hybrid density functional theory and Tully surface hopping. Homolytic bond breaking is approximately captured by allowing spin symmetry to break. The NAMD simulations reveal that non-adiabatic transitions selectively enhance the kinetic energy of certain internal degrees of freedom within approximately 50 fs...
October 5, 2016: Journal of Physical Chemistry Letters
Rebecca L Krupenevich, Alison L Pruziner, Ross H Miller
: Increased or abnormal loading on the intact limb is thought to contribute to the relatively high risk of knee osteoarthritis (OA) in this limb for individuals with unilateral lower limb loss. This theory has been assessed previously by studying walking, but knee joint loading during walking is often similar between individuals with limb loss and individuals without limb loss, prompting assessment of other movements that may place unusual loads on the knee. One such movement, hopping, is a form of locomotion that individuals with unilateral lower limb loss may situationally use instead of walking, but the mechanical effects of hopping on the intact limb are unknown...
September 16, 2016: Medicine and Science in Sports and Exercise
Nicky van Melick, Robert E H van Cingel, Frans Brooijmans, Camille Neeter, Tony van Tienen, Wim Hullegie, Maria W G Nijhuis-van der Sanden
AIM: The Royal Dutch Society for Physical Therapy (KNGF) instructed a multidisciplinary group of Dutch anterior cruciate ligament (ACL) experts to develop an evidence statement for rehabilitation after ACL reconstruction. DESIGN: Clinical practice guideline underpinned by systematic review and expert consensus. DATA SOURCES: A multidisciplinary working group and steering group systematically reviewed the literature and wrote the guideline...
December 2016: British Journal of Sports Medicine
Chiara Peila, Guido E Moro, Enrico Bertino, Laura Cavallarin, Marzia Giribaldi, Francesca Giuliani, Francesco Cresi, Alessandra Coscia
When a mother's milk is unavailable, the best alternative is donor milk (DM). Milk delivered to Human Milk Banks should be pasteurized in order to inactivate the microbial agents that may be present. Currently, pasteurization, performed at 62.5 °C for 30 min (Holder Pasteurization, HoP), is recommended for this purpose in international guidelines. Several studies have been performed to investigate the effects of HoP on the properties of DM. The present paper has the aim of reviewing the published papers on this topic, and to provide a comparison of the reported variations of biologically-active DM components before and after HoP...
August 2, 2016: Nutrients
Mahipal Ganji, Margreet Docter, Stuart F J Le Grice, Elio A Abbondanzieri
Finding the target site and associating in a specific orientation are essential tasks for DNA-binding proteins. In order to make the target search process as efficient as possible, proteins should not only rapidly diffuse to the target site but also dynamically explore multiple local configurations before diffusing away. Protein flipping is an example of this second process that has been observed previously, but the underlying mechanism of flipping remains unclear. Here, we probed the mechanism of protein flipping at the single molecule level, using HIV-1 reverse transcriptase (RT) as a model system...
September 30, 2016: Nucleic Acids Research
Kazuhiko Seki, Mariusz Wojcik
We study effective mobility in 2 dimensional (2D) and 3 dimensional (3D) systems, where hopping transitions of carriers are described by the Marcus equation under a Gaussian density of states in the dilute limit. Using an effective medium approximation (EMA), we determined the coefficient Cd for the effective mobility expressed by μeff∝exp-λ/4kBT-Cdσ(2)/kBT(2)/λ(kBT)(3/2), where λ is the reorganization energy, σ is the standard deviation of the Gaussian density of states, and kBT takes its usual meaning...
July 21, 2016: Journal of Chemical Physics
Rami Gherib, Liyuan Ye, Ilya G Ryabinkin, Artur F Izmaylov
The diagonal Born-Oppenheimer correction (DBOC) stems from the diagonal second derivative coupling term in the adiabatic representation, and it can have an arbitrary large magnitude when a gap between neighbouring Born-Oppenheimer (BO) potential energy surfaces (PESs) is closing. Nevertheless, DBOC is typically neglected in mixed quantum-classical methods of simulating nonadiabaticdynamics (e.g., fewest-switch surface hopping (FSSH) method). A straightforward addition of DBOC to BO PESs in the FSSH method, FSSH+D, has been shown to lead to numerically much inferior results for models containing conical intersections...
April 21, 2016: Journal of Chemical Physics
Grégory Geneste, L Bellaiche, Jean-Michel Kiat
The radio-frequency dielectric response of the lead-free Ba(Zr_{0.5}Ti_{0.5})O_{3} relaxor ferroelectric is simulated using a coarse-grained Hamiltonian. This concept, taken from real-space renormalization group theories, allows us to depict the collective behavior of correlated local modes gathered in blocks. Free-energy barriers for their thermally activated collective hopping are deduced from this ab initio-based approach, and used as input data for kinetic Monte Carlo simulations. The resulting numerical scheme allows us to simulate the dielectric response for external field frequencies ranging from kHz up to a few tens of MHz for the first time and to demonstrate, e...
June 17, 2016: Physical Review Letters
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