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Hop kinetic

Hiroki Sato, Daisuke Aoki, Toshikazu Takata
We developed novel size-complementary molecular and macromolecular rotaxanes using a 2,6-dimethylphenyl terminal as the axle-end-cap group in dibenzo-24-crown-8-ether (DB24C8)-based rotaxanes, where the 2,6-dimethylphenyl group was found to be less bulky than the 3,5-dimethylphenyl group. A series of molecular and macromolecular [2]rotaxanes that bear a 2,6-dimethylphenyl group as the axle-end-cap were synthesized using unsubstituted and fluorine-substituted DB24C8. Base-induced decomposition into their constituent components confirmed the occurrence of deslipping, which supports the size-complementarity of these rotaxanes...
February 2, 2018: Chemistry, An Asian Journal
Federico Raffone, Giancarlo Cicero
Even though resistance switching memories (RRAM) can be potentially employed in a broad variety of fields, like electronics and brain science, they are still affected by issues that prevent their application in circuitry. These problems are a consequence of the lack of detailed knowledge about the physical processes occurring in the device. In this work we propose a multi-scale simulation, combining Kinetic Monte Carlo and finite difference methods, to shed light on the yet unclear switching process occurring in valence change RRAM which are believed to work as consequence of the drift and diffusion of crystalline defects which act as dopants...
February 1, 2018: ACS Applied Materials & Interfaces
Jialin Mao, Utkarsh Doshi, Matthew Wright, Cornelis E C A Hop, Albert P Li, Yuan Chen
Plateable human hepatocytes with human plasma were utilized to generate the uptake transporter kinetic data for pravastatin, an organic anion transporting polypeptide (OATP) transporter substrate. The active hepatic uptake of pravastatin was determined with a Jmax value of 134.4 pmol/min/million cells and apparent Km of 76.77 µM in plateable human hepatocytes with human plasma. The physiologically based pharmacokinetic (PBPK) model with incorporation of these in vitro kinetic data successfully simulated the intravenous pharmacokinetic profile of pravastatin without applying scaling factor (the mean predicted AUC is within 1...
February 1, 2018: CPT: Pharmacometrics & Systems Pharmacology
Yiwei Li, Osman Kahraman, Christoph A Haselwandter
Diffusion can be conceptualized, at microscopic scales, as the random hopping of particles between neighboring lattice sites. In the case of diffusion in inhomogeneous media, distinct spatial domains in the system may yield distinct particle hopping rates. Starting from the master equations (MEs) governing diffusion in inhomogeneous media we derive here, for arbitrary spatial dimensions, the deterministic lattice equations (DLEs) specifying the average particle number at each lattice site for randomly diffusing particles in inhomogeneous media...
September 2017: Physical Review. E
Rui Zhang, Kenneth S Schweizer
The Elastically Collective Nonlinear Langevin Equation theory for one-component viscous liquids and suspensions is generalized to treat coupled slow activated relaxation and diffusion in glass-forming binary sphere mixtures of any composition, size ratio and inter-particle interactions. A trajectory-level dynamical coupling parameter concept is introduced to construct two coupled dynamic free energy functions for the smaller penetrant and larger matrix particle. A two-step dynamical picture is proposed where the first step process involves matrix-facilitated penetrant hopping quantified in a self-consistent manner based on a temporal coincidence condition...
January 18, 2018: Journal of Physical Chemistry. B
Emrah Kovalak, Tolga Atay, Cem Çetin, I Meltem Atay, Mustafa Onur Serbest
OBJECTIVE: Whether surgical or conservative treatment is more effective in allowing patients to return to physical activity after anterior cruciate ligament (ACL) injury is controversial. We sought to compare mid-term outcome measures between isolated ACL tear patients who underwent reconstruction followed by closed kinetic chain exercises and those who underwent neuromuscular training only. METHODS: We retrospectively evaluated patients with ACL tears who underwent post-surgery CKC strength training after ACL reconstruction (Group A), and patients who only underwent neuromuscular training (Group B) with a minimum follow-up time of 5 years...
December 28, 2017: Acta Orthopaedica et Traumatologica Turcica
Jiali Wang, Thomas Albers, Christof T Grewer
Glutamate transporters maintain a large glutamate concentration gradient across synaptic membranes and are, thus, critical for functioning of the excitatory synapse. Mammalian glutamate transporters concentrate glutamate inside cells through energetic coupling of glutamate flux to the transmembrane concentration gradient of Na+. Structural models based on an archeal homologue of mammalian glutamate transporters, GltPh, suggest an elevator-like carrier mechanism. However, the energetic determinants of this carrier-based movement are not well understood...
December 8, 2017: Journal of Physical Chemistry. B
Aleksandra Bazan-Wozniak, Piotr Nowicki, Robert Pietrzak
A technology of activated bio-carbons production from the residue left after supercritical extraction of hops is described. The effect of the variant of chemical activation and impregnation ratio on the physicochemical properties as well as sorption capacity towards toxic gas of acidic character (nitrogen dioxide), basic organic dye (aqueous solution of methylene blue - MB) and iodine was investigated. The materials obtained were activated bio-carbons of well-developed surface area ranging between 897 and 1095m2/g, showing clearly acidic character of the surface...
December 4, 2017: Environmental Research
Jean-Francois Nierengarten, Marie Steffenhagen, Alina Latus, Thi Minh Nguyet Trinh, Iwona Nierengarten, Ivan T Lucas, Suzanne Joiret, Jessem Landoulsi, Béatrice Delavaux-Nicot, Emmanuel Maisonhaute
A rotaxane scaffold incorporating two dithiolane anchoring units for the modification of gold surfaces has been functionalized with multiple copies of a redox unit, namely ferrocene. Surface modification has been first assessed at the single molecule level by atomic force microscopy (AFM) and scanning tunneling microscopy (STM) imaging, while tip enhanced Raman spectroscopy (TERS) provided the local vibrational signature of the ferrocenyl subunits of the rotaxanes grafted onto the gold surface. Finally, oxidation of the redox moieties within a rotaxane scaffold grafted onto gold microelectrodes has been investigated by ultrafast cyclic voltammetry...
December 5, 2017: Chemistry: a European Journal
Shaoyang Lin, Alireza K Ravari, Jie Zhu, Pavel Usov, Meng Cai, Spencer R Ahrenholtz, Yulia Pushkar, Amanda Morris
Investigation of chemical water oxidation was conducted on the [Ru(tpy)(dcbpy)OH2]2+ (tpy = 2,2':6',2''-terpyridine, dcbpy = 5,5'-dicarboxy-2,2'-bipyridine) -doped UiO-67 metal-organic framework (MOF). The MOF catalyst exhibited single site reaction pathway with similar kinetic behavior as the homogeneous Ru complex. The reaction was first order with respect to both the concentration of Ru catalyst and cerium ammonium nitrate (CAN), with kcat = 3 (±2) ×10-3 M-1s-1 in HNO3 (pH 0.5). The common degradation pathways of ligand dissociation and dimerization were precluded by MOF incorporation, leading to sustained catalysis and greater reusability as opposed to the molecular catalyst in homogeneous solution...
December 2, 2017: ChemSusChem
Starla D Glover, Robin Tyburski, Li Liang, Cecilia Tommos, Leif Hammarström
Protein "hole" hopping typically involves spatially arranged redox-active tryptophan and/or tyrosine residues. Thermodynamic information is scarce for this type of process. The well-structured α3W model protein was studied by protein film square wave voltammetry and transient absorption spectroscopy to obtain a comprehensive thermodynamic and kinetic description of a buried tryptophan residue. A Pourbaix diagram, correlating thermodynamic potentials (E°') with pH, is reported for W32 in α3W and compared to equivalent data recently presented for Y32 in α3Y (Ravichandran, K...
November 30, 2017: Journal of the American Chemical Society
Eugene Mamontov, Alexander I Kolesnikov, Sujatha Sampath, Jeffery L Yarger
Lithium-beryllium metal hydrides, which are structurally related to their parent compound, BeH2, offer the highest hydrogen storage capacity by weight among the metal hydrides (15.93 wt. % of hydrogen for LiBeH3). Challenging synthesis protocols have precluded conclusive determination of their crystallographic structure to date, but here we analyze directly the hydrogen hopping mechanisms in BeH2 and LiBeH3 using quasielastic neutron scattering, which is especially sensitive to single-particle dynamics of hydrogen...
November 24, 2017: Scientific Reports
Alejandro Méndez-Ardoy, Nagula Markandeya, Xuesong Li, Yu-Tang Tsai, Gilles Pecastaings, Thierry Buffeteau, Victor Maurizot, Luca Muccioli, Frédéric Castet, Ivan Huc, Dario M Bassani
Aromatic foldamers are bioinspired architectures whose potential use in materials remains largely unexplored. Here we report our investigation of vertical and horizontal charge transport over long distances in helical oligo-quinolinecarboxamide foldamers organized as single monolayers on Au or SiO2. Conductive atomic force microscopy showed that vertical conductivity is efficient and that it displays a low attenuation with foldamer length (0.06 Å(-1)). In contrast, horizontal charge transport is found to be negligible, demonstrating the strong anisotropy of foldamer monolayers...
October 1, 2017: Chemical Science
Hiroya Tanaka, Hideo Iizuka, Yuriy V Pershin, Massimiliano Di Ventra
Ionic Coulomb blockade in nanopores is a phenomenon that shares some similarities but also differences with its electronic ounterpart. Here, we investigate extensively this phenomenon using all-atom molecular dynamics of ionic transport through nanopores of about one nanometer in diameter and up to several nanometers in length. Our goal is to better understand the role of atomic roughness and structure of the pore walls in facilitating ionic Coulomb blockade. Our numerical results reveal the following general trends...
November 13, 2017: Nanotechnology
Mogens L L Andersen, Matheo Gundermann, Bente P Danielsen, Marianne N Lund
Thiol-containing proteins have been suggested to have antioxidative properties in beer. A kinetic model has been setup for the reactivity of thiols during early stages of oxidative degradation of beer. Kinetic analysis based on the proposed reaction mechanism allowed evaluation of the relative reactivity of beer components, such as bitter acids from hops and polyphenols. The rate constants for the reaction of 1-hydroxyethyl radicals, which are generated during radical mediated oxidation of ethanol in beer, with hop bitter acids and thiols were very similar, and the concentration of the compounds in beer is therefore essential for the relative reactivity...
November 12, 2017: Journal of Agricultural and Food Chemistry
Giridhar Nandipati, Xiujuan Jiang, Rama S Vemuri, Suveen Mathaudhu, Aashish Rohatgi
Si-atom and vacancy diffusion in α-Fe-Si alloys in the ferromagnetic state, with and without magnetic order and in various temperature ranges, is studied using AKSOME, an on-lattice self-learning KMC code. Si-atom diffusion in the dilute limit and vacancy diffusion in A2- phase of the α-Fe-Si alloy up to Si concentrations of 12at.% is studied in the temperature range of 350-700 K and 350-500 K, respectively. Local Si-atom neighborhood dependent activation energies for vacancy hops were calculated on-the-fly using a broken-bond model based on pairwise interaction...
November 1, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Hayley C Powell, Karin Grävare Silbernagel, Annelie Brorsson, Roy Tranberg, Richard W Willy
Study Design Cross-sectional laboratory study. Background Asymmetrical knee loading during jogging and hopping has been reported in individuals who have ruptured their Achilles tendon. No studies have examined knee loads in individuals post Achilles tendon rupture during high-demand tasks, such as single-limb landings. Objectives We sought to determine whether individuals post Achilles tendon rupture demonstrated asymmetrical knee loads and impact forces during drop countermovement jumps (CMJs). Methods Achilles tendon length and the single-leg heel-rise test for endurance were assessed in 34 individuals (31 male) 6...
January 2018: Journal of Orthopaedic and Sports Physical Therapy
Yangzheng Lin, Kristen A Fichthorn
We use first-principles density-functional theory to characterize the binding sites and diffusion mechanisms for a Ga adatom on the GaAs(001)β2(2 × 4) surface. Diffusion in this system is a complex process involving eleven unique binding sites and sixteen different hops between neighboring binding sites. Among the binding sites, we can identify four different superbasins such that the motion between binding sites within a superbasin is much faster than hops exiting the superbasin. To describe diffusion, we use a recently developed local superbasin kinetic Monte Carlo (LSKMC) method, which accelerates a conventional kinetic Monte Carlo (KMC) simulation by describing the superbasins as absorbing Markov chains...
October 21, 2017: Journal of Chemical Physics
Grégoire David, Nathalie Guihéry, Nicolas Ferré
Analytical expressions of the interactions present in the Heisenberg-Dirac van Vleck and Hubbard Hamiltonians have been derived as functions of both the energy of several broken symmetry DFT solutions and their expectation value of the S(2) spin operator. Then, following a strategy of decomposition of the magnetic exchange coupling into its main contributions (direct exchange, kinetic exchange, and spin polarization) and using a recently proposed method of spin decontamination, values of these interactions have been extracted...
November 7, 2017: Journal of Chemical Theory and Computation
Tania Luthra, Rahul Agarwal, Mamidala Estari, Uma Adepally, Subhabrata Sen
α-glucosidase is an essential enzyme located at the brush border of intestines. It is an important therapeutic target for type II diabetes. Herein we have designed a library of novel α-arylketones as inhibitors of α-glucosidase (yeast origin) via scaffold hopping and bioisosteric modification of known inhibitors of α-glucosidase. The design was validated through molecular docking that revealed strong binding interactions of the newly designed compounds against α-glucosidase. A library comprising of 15 compounds was synthesized in a combinatorial fashion, where the advanced amide intermediates were accessed through "shot gun" synthesis...
October 16, 2017: Scientific Reports
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