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Inverse dynamic

Emil Prodan, Kyle Dobiszewski, Alokik Kanwal, John Palmieri, Camelia Prodan
Mechanical systems can display topological characteristics similar to that of topological insulators. Here we report a large class of topological mechanical systems related to the BDI symmetry class. These are self-assembled chains of rigid bodies with an inversion centre and no reflection planes. The particle-hole symmetry characteristic to the BDI symmetry class stems from the distinct behaviour of the translational and rotational degrees of freedom under inversion. This and other generic properties led us to the remarkable conclusion that, by adjusting the gyration radius of the bodies, one can always simultaneously open a gap in the phonon spectrum, lock-in all the characteristic symmetries and generate a non-trivial topological invariant...
February 23, 2017: Nature Communications
Rina Sakai, Masataka Uchino, Terumasa Yoneo, Yasuaki Ohtaki, Hiroaki Minehara, Terumasa Matsuura, Tsutomu Gomi, Masanobu Ujihira
BACKGROUND: For internal fixation of AO classification Type B lateral malleolar fracture, insertion of lag screws into the fracture plane and fixation with a one-third tubular plate as a neutralization plate are the standard treatment procedures. The one-third tubular plate is processed to a hook shape and hung on the distal end of the fibula. In this study, to compare the function of the hook and lag screws of a one-third tubular plate and LCP for osteosynthesis of lateral malleolar fracture, mechanical indices of internal fixation were compared among the one-third tubular plates with lag screws with and without the hook and a locking compression plate...
February 23, 2017: Journal of Orthopaedic Surgery and Research
Michel Rickhaus, Marcel Mayor, Michal Juríček
Carbon allotropes constituted of sp(2)-hybridised carbon atoms display a variety of properties that arise from their delocalised π-conjugated electronic structure. Apart from carbon's planar allotropic form graphene, bent or curved structures, such as carbon nanotubes or fullerenes, respectively, have been discovered. In this Tutorial Review, we analyse and conceptually categorise chiral synthetic molecular fragments of non-planar sp(2)-carbon allotropes, including hypothetical forms of carbon that have been proposed to exist as stable entities...
February 22, 2017: Chemical Society Reviews
Zhiqiang Zhao, Zhaojun Zhang, Shu Liu, Dong H Zhang
Reactions occurring at a carbon atom through the Walden inversion mechanism are one of the most important and useful classes of reactions in chemistry. Here we report an accurate theoretical study of the simplest reaction of that type: the H+CH4 substitution reaction and its isotope analogues. It is found that the reaction threshold versus collision energy is considerably higher than the barrier height. The reaction exhibits a strong normal secondary isotope effect on the cross-sections measured above the reaction threshold, and a small but reverse secondary kinetic isotope effect at room temperature...
February 22, 2017: Nature Communications
Elizabeth Dickinson, John R P Arnold, Julie Fisher
The cause of the pregnancy condition preeclampsia (PE) is thought to be endothelial dysfunction caused by oxidative stress. As abnormal glucose tolerance has also been associated with PE, we use a fluorinated-mimic of this metabolite to establish whether any oxidative damage to lipids and proteins in the erythrocyte membrane has increased cell membrane permeability. Data were acquired using (19)F Dynamic-NMR (DNMR) to measure exchange of 3-fluoro-3-deoxyglucose (3-FDG) across the membrane of erythrocytes from 10 pregnant women (5 healthy control women, and 5 from women suffering from PE)...
February 21, 2017: Journal of Biomolecular NMR
Sara Behforootan, Panagiotis E Chatzistergos, Nachiappan Chockalingam, Roozbeh Naemi
INTRODUCTION: Pathological conditions such as diabetic foot and plantar heel pain are associated with changes in the mechanical properties of plantar soft tissue. However, the causes and implications of these changes are not yet fully understood. This is mainly because accurate assessment of the mechanical properties of plantar soft tissue in the clinic remains extremely challenging. PURPOSE: To develop a clinically viable non-invasive method of assessing the mechanical properties of the heel pad...
February 9, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Kikuko Hotta, Masataka Kikuchi, Takuya Kitamoto, Aya Kitamoto, Yuji Ogawa, Yasushi Honda, Takaomi Kessoku, Kaori Kobayashi, Masato Yoneda, Kento Imajo, Wataru Tomeno, Akihiro Nakaya, Yutaka Suzuki, Satoru Saito, Atsushi Nakajima
AIM: Nonalcoholic fatty liver disease (NAFLD) progresses because of the interaction between numerous genes. Thus, we performed weighted gene co-expression network analysis to identify core gene networks and key genes associated with NAFLD progression. METHODS: We enrolled 39 patients with mild NAFLD (fibrosis stages 0 to 2) and 21 with advanced NAFLD (fibrosis stages 3 or 4). Total RNA was extracted from frozen liver biopsies, and sequenced to capture a large dynamic range of expression levels...
February 20, 2017: Hepatology Research: the Official Journal of the Japan Society of Hepatology
Jamie Conyard, Peter Stacko, Jiawen Chen, Sophie McDonagh, Christopher R Hall, Sergey P Laptenok, Wesley R Browne, Ben L Feringa, Stephen R Meech
Photochemically driven molecular motors convert the energy of incident radiation to intramolecular rotational motion. The motor molecules considered here execute four step unidirectional rotational motion. This comprises a pair of successive light induced isomerizations to a metastable state followed by thermal helix inversions. The internal rotation of a large molecular unit required in these steps is expected to be sensitive to both the viscosity of the medium and the volume of the rotating unit. In this work we describe a study of motor motion in both ground and excited states as a function of the size of the rotating units...
February 20, 2017: Journal of Physical Chemistry. A
Shubhangi Agarwal, Sanjay Dey, Biplab Ghosh, Maitree Biswas, Jhimli Dasgupta
Molecular mechanisms of xenosiderophore and heme acquisitions using periplasmic binding protein (PBP) dependent ATP-binding cassette transporters to scavenge the essential nutrient iron are elusive yet in Vibrio cholerae. Our current study delineates the structures, dynamics and ligand binding properties of two Type III PBPs of V. cholerae, VcFhuD and VcHutB. Through crystal structures and fluorescence quenching studies we demonstrate unique features of VcFhuD to bind both hydroxamate and catecholate type xenosiderophores...
February 20, 2017: Scientific Reports
Alison S Walker, Guilherme Neves, Federico Grillo, Rachel E Jackson, Mark Rigby, Cian O'Donnell, Andrew S Lowe, Gema Vizcay-Barrena, Roland A Fleck, Juan Burrone
Neurons receive a multitude of synaptic inputs along their dendritic arbor, but how this highly heterogeneous population of synaptic compartments is spatially organized remains unclear. By measuring N-methyl-d-aspartic acid receptor (NMDAR)-driven calcium responses in single spines, we provide a spatial map of synaptic calcium signals along dendritic arbors of hippocampal neurons and relate this to measures of synapse structure. We find that quantal NMDAR calcium signals increase in amplitude as they approach a thinning dendritic tip end...
February 16, 2017: Proceedings of the National Academy of Sciences of the United States of America
René Felix Reinhart, Zeeshan Shareef, Jochen Jakob Steil
Feed-forward model-based control relies on models of the controlled plant, e.g., in robotics on accurate knowledge of manipulator kinematics or dynamics. However, mechanical and analytical models do not capture all aspects of a plant's intrinsic properties and there remain unmodeled dynamics due to varying parameters, unmodeled friction or soft materials. In this context, machine learning is an alternative suitable technique to extract non-linear plant models from data. However, fully data-based models suffer from inaccuracies as well and are inefficient if they include learning of well known analytical models...
February 8, 2017: Sensors
Muhammet Uzuntarla, Joaquin J Torres, Paul So, Mahmut Ozer, Ernest Barreto
We investigate the behavior of a model neuron that receives a biophysically realistic noisy postsynaptic current based on uncorrelated spiking activity from a large number of afferents. We show that, with static synapses, such noise can give rise to inverse stochastic resonance (ISR) as a function of the presynaptic firing rate. We compare this to the case with dynamic synapses that feature short-term synaptic plasticity and show that the interval of presynaptic firing rate over which ISR exists can be extended or diminished...
January 2017: Physical Review. E
Takahiro Nemoto, Esteban Guevara Hidalgo, Vivien Lecomte
The Giardinà-Kurchan-Peliti algorithm is a numerical procedure that uses population dynamics in order to calculate large deviation functions associated to the distribution of time-averaged observables. To study the numerical errors of this algorithm, we explicitly devise a stochastic birth-death process that describes the time evolution of the population probability. From this formulation, we derive that systematic errors of the algorithm decrease proportionally to the inverse of the population size. Based on this observation, we propose a simple interpolation technique for the better estimation of large deviation functions...
January 2017: Physical Review. E
David M Ackerman, James W Evans
We perform a tracer counterpermeation (TCP) analysis for a stochastic model of diffusive transport through a narrow linear pore where passing of species within the pore is inhibited or even excluded (single-file diffusion). TCP involves differently labeled but otherwise identical particles from two decoupled infinite reservoirs adsorbing into opposite ends of the pore, and desorbing from either end. In addition to transient behavior, we assess steady-state concentration profiles, spatial correlations, particle number fluctuations, and diffusion fluxes through the pore...
January 2017: Physical Review. E
Guofeng Mei, Xiaoqun Wu, Yingfei Wang, Mi Hu, Jun-An Lu, Guanrong Chen
The coexistence of multiple types of interactions within social, technological, and biological networks has motivated the study of the multilayer nature of real-world networks. Meanwhile, identifying network structures from dynamical observations is an essential issue pervading over the current research on complex networks. This paper addresses the problem of structure identification for multilayer networks, which is an important topic but involves a challenging inverse problem. To clearly reveal the formalism, the simplest two-layer network model is considered and a new approach to identifying the structure of one layer is proposed...
February 13, 2017: IEEE Transactions on Cybernetics
Scott Schieman, Jonathan Koltai
One of the most pervasive statements about stratification and health identifies the strong inverse relationship-or gradient-between socioeconomic status (SES) and poor health. We elaborate on the ways that the SES-based gradient in stress exposure contributes to nuances in the SES-health association. In analyses of the 2008 National Study of the Changing Workforce, we find some evidence that the inverse association between SES and health outcomes is finely graded-but several 'pockets of complexity' emerge. First, education and income have different associations with health and well-being...
March 2017: Social Science Research
Bo Zhang, Sabah M M Abu-Khumra, Abdellah Aibout, Anthony J Horsewill
In NMR the polarisation of the Zeeman system may be routinely probed and manipulated by applying resonant rf pulses. As with spin-1/2 nuclei, at low temperature the quantum tunnelling states of a methyl rotor are characterised by two energy levels and it is interesting to consider how these tunnelling states might be probed and manipulated in an analogous way to nuclear spins in NMR. In this paper experimental procedures based on magnetic field-cycling NMR are described where, by irradiating methyl tunnelling sidebands, the polarisations of the methyl tunnelling systems are measured and manipulated in a prescribed fashion...
February 14, 2017: Journal of Chemical Physics
Yugang Zhuang, Hu Peng, Yuanzhuo Chen, Shuqin Zhou, Yanqing Chen
Sepsis, an under-recognized health problem, is a major cause of death.  More than 750,000 individuals develop sepsis annually, of whom 215,000 die of the disease. Clinical and experimental evidence indicates that patients with sepsis present with rapid impairment of immune function; biomarkers are therefore needed to enable early detection of this condition. Reduced monocyte human leukocyte antigen-DR (HLA-DR) expression, which is measured by flow cytometry, is currently the most popular biomarker for sepsis detection...
March 1, 2017: Frontiers in Bioscience (Landmark Edition)
Anis Yuniati, Te-Lun Mai, Chi-Ming Chen
In this study, we used the Hodgkin-Huxley (HH) model of neurons to investigate the phase diagram of a developing single-layer neural network and that of a network consisting of two weakly coupled neural layers. These networks are noise driven and learn through the spike-timing-dependent plasticity (STDP) or the inverse STDP rules. We described how these networks transited from a non-synchronous background activity state (BAS) to a synchronous firing state (SFS) by varying the network connectivity and the learning efficacy...
2017: Frontiers in Computational Neuroscience
Jean-Baptiste Woillard, Jean Debord, Isabelle Benz-de-Bretagne, Franck Saint-Marcoux, Pascal Turlure, Stéphane Girault, Julie Abraham, Sylvain Choquet, Pierre Marquet, Chantal Barin-Le Guellec
BACKGROUND: MRP2/ABCC2, an efflux transporter expressed at the proximal renal tubule, is rate limiting for urine excretion of coproporphyrin (UCP) isomers I and III, translating in high UCP (I/(I+III)) ratio in MRP2-deficient patients presenting with the Dubin-Johnson Syndrome. MRP2 is also a major contributor to methotrexate (MTX) clearance. As MTX is both a substrate and an inhibitor of MRP2, time course of the concentrations of MTX in blood could induce functional modification of MRP2 over time, which in turn can modify its own elimination rate...
February 11, 2017: Therapeutic Drug Monitoring
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