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Michael A Samaan, Stacie I Ringleb, Sebastian Y Bawab, Eric K Greska, Joshua T Weinhandl
The effects of ACL-reconstruction on lower extremity joint mechanics during performance of the Star Excursion Balance Test (SEBT) and Single Leg Hop (SLH) are limited. The purpose of this study was to determine if altered lower extremity mechanics occur during the SEBT and SLH after ACL-reconstruction. One female Division I collegiate athlete performed the SEBT and SLH tasks, bilaterally, both before ACL injury and 27 months after ACL-reconstruction. Maximal reach, hop distances, lower extremity joint kinematics and moments were compared between both time points...
March 15, 2018: Computer Methods in Biomechanics and Biomedical Engineering
Xuecheng Tao, Philip Shushkov, Thomas F Miller
We describe a path-integral approach for including nuclear quantum effects in non-adiabatic chemical dynamics simulations. For a general physical system with multiple electronic energy levels, a corresponding isomorphic Hamiltonian is introduced such that Boltzmann sampling of the isomorphic Hamiltonian with classical nuclear degrees of freedom yields the exact quantum Boltzmann distribution for the original physical system. In the limit of a single electronic energy level, the isomorphic Hamiltonian reduces to the familiar cases of either ring polymer molecular dynamics (RPMD) or centroid molecular dynamics Hamiltonians, depending on the implementation...
March 14, 2018: Journal of Chemical Physics
Roel Tempelaar, David R Reichman
Fewest-switches surface hopping (FSSH) is perhaps the most widely used mixed quantum-classical approach for the modeling of non-adiabatic processes, but its original formulation is restricted to (adiabatic) population terms of the quantum density matrix, leaving its implementations with an inconsistency in the treatment of populations and coherences. In this article, we propose a generalization of FSSH that treats both coherence and population terms on equal footing and which formally reduces to the conventional FSSH algorithm for the case of populations...
March 14, 2018: Journal of Chemical Physics
Xin Bai, Jing Qiu, Linjun Wang
We provide an in-depth investigation of the time interval convergence when both trivial crossing and decoherence corrections are applied to Tully's fewest switches surface hopping (FSSH) algorithm. Using one force-based and one energy-based decoherence strategies as examples, we show decoherence corrections intrinsically enhance the trivial crossing problem. We propose a restricted decoherence (RD) strategy and incorporate it into the self-consistent (SC) fewest switches surface hopping algorithm [L. Wang and O...
March 14, 2018: Journal of Chemical Physics
Alexei A Kananenka, Xiang Sun, Alexander Schubert, Barry D Dunietz, Eitan Geva
We present a comprehensive comparison of the following mixed quantum-classical methods for calculating electronic transition rates: (1) nonequilibrium Fermi's golden rule, (2) mixed quantum-classical Liouville method, (3) mean-field (Ehrenfest) mixed quantum-classical method, and (4) fewest switches surface-hopping method (in diabatic and adiabatic representations). The comparison is performed on the Garg-Onuchic-Ambegaokar benchmark charge-transfer model, over a broad range of temperatures and electronic coupling strengths, with different nonequilibrium initial states, in the normal and inverted regimes...
March 14, 2018: Journal of Chemical Physics
E Pafong Sanjon, B Drossel, M Vogel
Silica is a network-forming liquid that shares many properties with water due to its tetrahedral structure. It undergoes a transition from a fragile to a strong liquid as the temperature is decreased, which is accompanied by a structural change to lower density and higher tetrahedral order. In order to disentangle the effects of Coulomb and van der Waals interactions on the structure and dynamics of liquid silica, we modify the bond polarity by changing the partial charges assigned to each atom. Using molecular dynamics simulations, we show that density, tetrahedral order, and structural relaxation times decrease when reducing bond polarity...
March 14, 2018: Journal of Chemical Physics
Kateřina Štulíková, Marcel Karabín, Jakub Nešpor, Pavel Dostálek
Hop ( Humulus lupulus L.), as a key ingredient for beer brewing, is also a source of many biologically active molecules. A notable compound, 8-prenylnaringenin (8-PN), structurally belonging to the group of prenylated flavonoids, was shown to be a potent phytoestrogen, and thus, became the topic of active research. Here, we overview the pharmacological properties of 8-PN and its therapeutic opportunities. Due to its estrogenic effects, administration of 8-PN represents a novel therapeutic approach to the treatment of menopausal and post-menopausal symptoms that occur as a consequence of a progressive decline in hormone levels in women...
March 15, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Pavel Honzatko, Yauhen Baravets, Ashwin Kumar Myakalwar
We present a broadly tunable single-frequency ytterbium-doped fiber laser. Its broadband tunability is made possible by low resonator losses. The wavelength is determined by a grating filter, while the single-frequency regime is achieved by filtering the longitudinal modes in a fiber ring resonance filter. We obtained a tuning range from 1023 nm to 1107 nm. A feedback loop driving a fiber stretcher actuated by a piezo-element prevents mode hopping. Based on the coherent delayed self-heterodyne interferometry, the laser linewidth is estimated to be 600 Hz with feedback open and 11...
March 15, 2018: Optics Letters
S Debnath, N M Linke, S-T Wang, C Figgatt, K A Landsman, L-M Duan, C Monroe
The local phonon modes in a Coulomb crystal of trapped ions can represent a Hubbard system of coupled bosons. We selectively prepare single excitations at each site and observe free hopping of a boson between sites, mediated by the long-range Coulomb interaction between ions. We then implement phonon blockades on targeted sites by driving a Jaynes-Cummings interaction on individually addressed ions to couple their internal spin to the local phonon mode. The resulting dressed states have energy splittings that can be tuned to suppress phonon hopping into the site...
February 16, 2018: Physical Review Letters
Yancong Feng, Rui Tan, Yan Zhao, Rongtan Gao, Luyi Yang, Jinlong Yang, Hao Li, Guofu Zhou, Haibiao Chen, Feng Pan
A novel hybrid single Li-ion conductor (SLIC) for a Li-ion solid electrolyte was prepared by mixing aluminate complexes-polyethylene glycol (LiAl-PEG) and polyethylene oxide (PEO) for solid-state Li-ion batteries. The LiAl-PEG/PEO blend possesses high thermal stability and electrochemical stability with an oxidation decomposition voltage up to 4.8 V. Notably, this hybrid SLIC exhibits not only excellent Li-ion migration kinetics, but also good ionic conductivity as high as 4.0 × 10-5 and 2.6 × 10-4 S cm-1 at 30 and 100 °C, respectively, which is much higher than previously reported SLICs...
March 15, 2018: Nanoscale
Shusuke Kasamatsu, Osamu Sugino
We report first-principles simulation of polarization mechanisms in hydroxyapatite to explain the underlying mechanism behind the reported ion conductivities and polarization under electrical poling at elevated temperatures. It is found that ion conduction occurs mainly in the column of OH- ions along the c-axis through a combination of the flipping of OH- ions, exchange of proton vacancies between OH- ions, and the hopping of the OH- vacancy. The calculated activation energies are consistent with those found in conductivity measurements and thermally stimulated depolarization current measurements...
March 15, 2018: Physical Chemistry Chemical Physics: PCCP
Colin R O'Dowd, Matthew D Helm, J S Shane Rountree, Jakub T Flasz, Elias Arkoudis, Hugues Miel, Peter R Hewitt, Linda Jordan, Oliver Barker, Caroline Hughes, Ewelina Rozycka, Eamon Cassidy, Keeva McClelland, Ewa Odrzywol, Natalie Page, Stephanie Feutren-Burton, Scarlett Dvorkin, Gerald Gavory, Timothy Harrison
Ubiquitin specific protease 7 (USP7, HAUSP) has become an attractive target in drug discovery due to the role it plays in modulating Mdm2 levels and consequently p53. Increasing interest in USP7 is emerging due to its potential involvement in oncogenic pathways as well as possible roles in both metabolic and immune disorders in addition to viral infections. Potent, novel, and selective inhibitors of USP7 have been developed using both rational and structure-guided design enabled by high-resolution cocrystallography...
March 8, 2018: ACS Medicinal Chemistry Letters
Jeffrey W Jordan, Carolyn A Stalgaitis, John Charles, Patrick A Madden, Anjana G Radhakrishnan, Daniel Saggese
PURPOSE: Peer crowds are macro-level subcultures that share similarities across geographic areas. Over the past decade, dozens of studies have explored the association between adolescent peer crowds and risk behaviors, and how they can inform public health efforts. However, despite the interest, researchers have not yet reported on crowd size and risk levels from a representative sample, making it difficult for practitioners to apply peer crowd science to interventions. The current study reports findings from the first statewide representative sample of adolescent peer crowd identification and health behaviors...
February 1, 2018: Health Education & Behavior: the Official Publication of the Society for Public Health Education
Fabio Giardina, Fumiya Iida
Locomotion of machines and robots operating in rough terrain is strongly influenced by the mechanics of the ground-machine interactions. A rolling wheel in terrain with obstacles is subject to collisional energy losses, which is governed by mechanics comparable to hopping or walking locomotion. Here we investigate the energetic cost associated with overcoming an obstacle for rolling and hopping locomotion, using a simple mechanics model. The model considers collision-based interactions with the ground and the obstacle, without frictional losses, and we quantify, analyse, and compare the sources of energetic costs for three locomotion strategies...
2018: PloS One
Cristina Fernández-García, Lisa Rancan, Sergio D Paredes, César Montero, Mónica de la Fuente, Elena Vara, Jesús A F Tresguerres
BACKGROUND AND AIMS: Aging is associated with a deregulation of biological systems that lead to an increase in oxidative stress, inflammation, and apoptosis, among other effects. Xanthohumol is the main preylated chalcone present in hops (Humulus lupulus L.) whose antioxidant, anti-inflammatory and chemopreventive properties have been shown in recent years. In the present study, the possible protective effects of xanthohumol on liver alterations associated with aging were evaluated. METHODS: Male young and old senescence-accelerated prone mice (SAMP8), aged 2 and 10 months, respectively, were divided into four groups: non-treated young, non-treated old, old treated with 1 mg/kg/day xanthohumol, and old treated with 5 mg/kg/day xanthohumol...
March 13, 2018: European Journal of Nutrition
Andrew J Kossow, Tyler G DeChiara, Steve M Neahous, William P Ebben
Plyometric exercises are frequently performed as part of a strength and conditioning program. Most studies assessed the kinetics of plyometric exercises primarily performed in the vertical plane. The purpose of this study was to evaluate the multi-planar kinetic characteristics of a variety of plyometric exercises, which have a significant horizontal component. This study also sought to assess sex differences in the intensity progression of these exercises. Ten men and ten women served as subjects. The subjects performed a variety of plyometric exercises including the double leg hop, standing long jump, single leg standing long jump, bounding, skipping, power skipping, cone hops, and 45...
March 12, 2018: Journal of Strength and Conditioning Research
Jan Moritz Seliger, Livia Misuri, Edmund Maser, Jan Hintzpeter
Xanthohumol (XN), a prenylated chalcone unique to hops (Humulus lupulus) and two derived prenylflavanones, isoxanthohumol (IX) and 8-prenylnaringenin (8-PN) gained increasing attention as potential anti-diabetic and cancer preventive compounds. Two enzymes of the aldo-keto reductase (AKR) superfamily are notable pharmacological targets in cancer therapy (AKR1B10) and in the treatment of diabetic complications (AKR1B1). Our results show that XN, IX and 8-PN are potent uncompetitive, tight-binding inhibitors of human aldose reductase AKR1B1 (Ki  = 15...
December 2018: Journal of Enzyme Inhibition and Medicinal Chemistry
Penghui Wang, Lulu Jiang, Yang Cao, Xiaodan Zhang, Bangjing Chen, Shiyu Zhang, Ke Huang, Deyong Ye, Lu Zhou
Phosphoglycerate mutase 1 (PGAM1) is a glycolytic enzyme that dynamically converts 3-phosphoglycerate (3PG) to 2-phosphoglycerate (2PG), which was upregulated to coordinate glycolysis, pentose phosphate pathway (PPP) and serine biosynthesis to promote cancer cell proliferation and tumor growth in a variety of cancers. However, only a few inhibitors of PGAM1 have been reported with poor molecular or cellular efficacy. In this paper, a series of xanthone derivatives were discovered as novel PGAM1 inhibitors through scaffold hopping and sulfonamide reversal strategy based on the lead compound PGMI-004A...
February 24, 2018: Bioorganic & Medicinal Chemistry
Yulei Bai, Yanzhou Zhou, Zhaoshui He, Shengli Xie
A new method for the synthesis of wavenumber series before and after mode hopping is proposed for depth-resolved wavenumber scanning interferometry. The classical Fourier transform is not suitable for mode hopping; consequently, the wavenumber scanning range of diode lasers is rather narrow, reducing the depth resolution and measurement accuracy. We show that the discontinuity in wavenumber domain interferograms caused by mode hopping can be removed by introducing the phase compensation of the interference spectrum...
March 5, 2018: Optics Express
Shuailong Zhang, Adele Nikitina, Yujie Chen, Yanfeng Zhang, Lin Liu, Andrew G Flood, Joan Juvert, M Dean Chamberlain, Nazir P Kherani, Steven L Neale, Aaron R Wheeler
Optoelectronic tweezers (OET) are a microsystem actuation technology capable of moving microparticles at mm s-1 velocities with nN forces. In this work, we analyze the behavior of particles manipulated by negative dielectrophoresis (DEP) forces in an OET trap. A user-friendly computer interface was developed to generate a circular rotating light pattern to control the movement of the particles, allowing their force profiles to be conveniently measured. Three-dimensional simulations were carried out to clarify the experimental results, and the DEP forces acting on the particles were simulated by integrating the Maxwell stress tensor...
March 5, 2018: Optics Express
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