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https://www.readbyqxmd.com/read/28920986/stratification-in-binary-colloidal-polymer-films-experiment-and-simulations
#1
D K Makepeace, A Fortini, A Markov, P Locatelli, C Lindsay, S Moorhouse, R Lind, R P Sear, J L Keddie
When films are deposited from mixtures of colloidal particles of two different sizes, a diverse range of functional structures can result. One structure of particular interest is a stratified film in which the top surface layer has a composition different than in the interior. Here, we explore the conditions under which a stratified layer of small particles develops spontaneously in a colloidal film that is cast from a binary mixture of small and large polymer particles that are suspended in water. A recent model, which considers the cross-interaction between the large and small particles (Zhou et al...
September 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28901961/effect-of-stretching-on-thoracolumbar-fascia-injury-and-movement-restriction-in-a-porcine-model
#2
Helene M Langevin, James Bishop, Rhonda Maple, Gary J Badger, James R Fox
OBJECTIVE: Stretching of fascia is an important component of manual and movement therapies. We previously showed that in pigs, a unilateral thoracolumbar fascia injury combined with movement restriction (hobble) produced contralateral loss of fascia mobility (shear strain during passive trunk flexion measured with ultrasound) similar to findings in human subjects with chronic low back pain. We now tested whether such abnormalities could be reversed by removing the hobble with or without daily stretching for 1 mo...
September 10, 2017: American Journal of Physical Medicine & Rehabilitation
https://www.readbyqxmd.com/read/28894003/reexamining-the-origin-of-the-directionality-of-myosin-v
#3
Raphael Alhadeff, Arieh Warshel
The nature of the conversion of chemical energy to directional motion in myosin V is examined by careful simulations that include two complementary methods: direct Langevin Dynamics (LD) simulations with a scaled-down potential that provided a detailed time-resolved mechanism, and kinetic equations solution for the ensemble long-time propagation (based on information collected for segments of the landscape using LD simulations and experimental information). It is found that the directionality is due to the rate-limiting ADP release step rather than the potential energy of the lever arm angle...
September 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28884664/early-nasopharyngeal-microbial-signature-associated-with-severe-influenza-in-children-a-retrospective-pilot-study
#4
Stanley Langevin, Maxime Pichon, Elise Smith, Juliet Morrison, Zachary Bent, Richard Green, Kristi Baker, Owen Solberg, Yves Gillet, Etienne Javouhey, Bruno Lina, Michael G Katze, Laurence Josset
A few studies have highlighted the importance of the respiratory microbiome in modulating the frequency and outcome of viral respiratory infections. However, there are insufficient data on the use of microbial signatures as prognostic biomarkers to predict respiratory disease outcomes. In this study, we aimed to evaluate whether specific bacterial community compositions in the nasopharynx of children at the time of hospitalization are associated with different influenza clinical outcomes. We utilized retrospective nasopharyngeal (NP) samples (n=36) collected at the time of hospital arrival from children who were infected with influenza virus and had been symptomatic for less than 2 days...
September 8, 2017: Journal of General Virology
https://www.readbyqxmd.com/read/28871961/genetic-epidemiology-of-dengue-viruses-in-phase-iii-trials-of-the-cyd-tetravalent-dengue-vaccine-and-implications-for-efficacy
#5
Maia A Rabaa, Yves Girerd-Chambaz, Kien Duong Thi Hue, Trung Vu Tuan, Bridget Wills, Matthew Bonaparte, Diane van der Vliet, Edith Langevin, Margarita Cortes, Betzana Zambrano, Corinne Dunod, Anh Wartel-Tram, Nicholas Jackson, Cameron P Simmons
This study defined the genetic epidemiology of dengue viruses (DENV) in two pivotal phase III trials of the tetravalent dengue vaccine, CYD-TDV, and thereby enabled virus genotype-specific estimates of vaccine efficacy (VE). Envelope gene sequences (n = 661) from 11 DENV genotypes in 10 endemic countries provided a contemporaneous global snapshot of DENV population genetics and revealed high amino acid identity between the E genes of vaccine strains and wild-type viruses from trial participants, including at epitope sites targeted by virus neutralising human monoclonal antibodies...
September 5, 2017: ELife
https://www.readbyqxmd.com/read/28870330/evidence-based-guidelines-for-being-supportive-of-people-who-stutter-in-north-america
#6
Kenneth O St Louis, Farzan Irani, Rodney M Gabel, Stephanie Hughes, Marilyn Langevin, Midori Rodriguez, Kathleen Scaler Scott, Mary E Weidner
While many resources, particularly those available on the Internet, provide suggestions for fluent speakers as they interact with people who stutter (PWS), little evidence exists to support these suggestions. Thus, the purpose of this study was to document the supportiveness of common public reactions, behaviors, or interventions to stuttering by PWS.Methods 148 PWS completed the Personal Appraisal of Support for Stuttering-Adults. Additionally, a comparison of the opinions of adults who stutter based on gender and their involvement in self-help/support groups was undertaken...
September 2017: Journal of Fluency Disorders
https://www.readbyqxmd.com/read/28863691/tinylev-a-multi-emitter-single-axis-acoustic-levitator
#7
Asier Marzo, Adrian Barnes, Bruce W Drinkwater
Acoustic levitation has the potential to enable novel studies due to its ability to hold a wide variety of substances against gravity under container-less conditions. It has found application in spectroscopy, chemistry, and the study of organisms in microgravity. Current levitators are constructed using Langevin horns that need to be manufactured to high tolerance with carefully matched resonant frequencies. This resonance condition is hard to maintain as their temperature changes due to transduction heating...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28843081/cumulative-childhood-trauma-emotion-regulation-dissociation-and-behavior-problems-in-school-aged-sexual-abuse-victims
#8
Martine Hébert, Rachel Langevin, Essaïd Oussaïd
BACKGROUND: Child sexual abuse is associated with a plethora of devastating repercussions. A significant number of sexually abused children are likely to experience other forms of maltreatment that can seriously affect their emotion regulation abilities and impede on their development. The aim of the study was to test emotion regulation and dissociation as mediators in the association between cumulative childhood trauma and internalized and externalized behavior problems in child victims of sexual abuse...
August 18, 2017: Journal of Affective Disorders
https://www.readbyqxmd.com/read/28810800/confinement-curvature-and-attractive-interaction-effects-on-polymer-surface-adsorption
#9
Wei Chien, Yeng-Long Chen
We investigate the conformation and dynamics of a semi-flexible polymer near an attractive plane or a cylindrical post using Langevin dynamics. We characterize the transition from the desorbed to absorbed state and quantify how absorption depends on the attraction interaction, polymer molecular weight, polymer flexibility, intra-polymer interaction, and micro-confinement. We find that the critical point of adsorption for ideal flexible polymers only weakly depends on confinement. However, the critical point of adsorption increases significantly for self-avoiding flexible polymers and under confinement, deviating from scaling theory predictions...
August 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28810783/self-consistent-calculation-of-protein-folding-pathways
#10
S Orioli, S A Beccara, P Faccioli
We introduce an iterative algorithm to efficiently simulate protein folding and other conformational transitions, using state-of-the-art all-atom force fields. Starting from the Langevin equation, we obtain a self-consistent stochastic equation of motion, which directly yields the reaction pathways. From the solution of this set of equations we derive a stochastic estimate of the reaction coordinate. We validate this approach against the results of plain MD simulations of the folding of a small protein, which were performed on the Anton supercomputer...
August 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28810751/communication-on-the-diffusion-tensor-in-macroscopic-theory-of-cavitation
#11
Vitaly A Shneidman
The classical description of nucleation of cavities in a stretched fluid relies on a one-dimensional Fokker-Planck equation (FPE) in the space of their sizes r, with the diffusion coefficient D(r) constructed for all r from macroscopic hydrodynamics and thermodynamics, as shown by Zeldovich. When additional variables (e.g., vapor pressure) are required to describe the state of a bubble, a similar approach to construct a diffusion tensor D^ generally works only in the direct vicinity of the thermodynamic saddle point corresponding to the critical nucleus...
August 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28809793/the-degree-of-temporal-synchronization-of-the-pulse-oscillations-from-a-gain-switched-multimode-semiconductor-laser
#12
Kenji Wada, Naoaki Kitagawa, Tetsuya Matsuyama
Langevin noise leads to inhibition of the temporal synchronization of the pulse oscillations from a gain-switched multimode semiconductor laser, resulting in the power reduction in optical beat detection. In this paper, the degree of the temporal synchronization of the pulse oscillations was examined by numerically estimating the output energy in THz time-domain spectroscopy (THz-TDS) using multimode semiconductor laser rate equations that include Langevin noise. The degree was estimated to be 95.5% from the ratio of the averaged THz-TDS output energy for the case where Langevin noise was included to that for when Langevin noise was excluded...
August 15, 2017: Materials
https://www.readbyqxmd.com/read/28803628/dominique-langevin-festschrift-four-decades-opening-gates-in-colloid-and-interface-science
#13
EDITORIAL
(no author information available yet)
No abstract text is available yet for this article.
August 5, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28799384/dynamical-density-functional-theory-with-hydrodynamic-interactions-in-confined-geometries
#14
B D Goddard, A Nold, S Kalliadasis
We study the dynamics of colloidal fluids in both unconfined geometries and when confined by a hard wall. Under minimal assumptions, we derive a dynamical density functional theory (DDFT) which includes hydrodynamic interactions (HI; bath-mediated forces). By using an efficient numerical scheme based on pseudospectral methods for integro-differential equations, we demonstrate its excellent agreement with the full underlying Langevin equations for systems of hard disks in partial confinement. We further use the derived DDFT formalism to elucidate the crucial effects of HI in confined systems...
December 7, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28793766/stratification-in-drying-polymer-polymer-and-colloid-polymer-mixtures
#15
Michael P Howard, Arash Nikoubashman, Athanassios Z Panagiotopoulos
Drying polymer-polymer and colloid-polymer mixtures were studied using Langevin dynamics computer simulations. Polymer-polymer mixtures vertically stratified into layers, with the shorter polymers enriched near the drying interface and the longer polymers pushed down toward the substrate. Colloid-polymer mixtures stratified into a polymer-on-top structure when the polymer radius of gyration was comparable to or smaller than the colloid diameter, and a colloid-on-top structure otherwise. We also developed a theoretical model for the drying mixtures based on dynamical density functional theory, which gave excellent quantitative agreement with the simulations for the polymer-polymer mixtures and qualitatively predicted the observed polymer-on-top or colloid-on-top structures for the colloid-polymer mixtures...
August 9, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28752562/gas-phase-chemical-ionization-of-4-alkyl-branched-chain-carboxylic-acids-and-3-methylindole-using-h3-o-no-and-o2-ions
#16
Hardy Z Castada, Sheryl Barringer, Macdonald Wick
RATIONALE: 4-methyloctanoic acid, 4-ethyloctanoic acid, 4-methylnonanoic acid, and 3-methylindole are primary contributors to the distinctive aroma and flavor of lamb meat. The reactions of H3 O(+) , NO(+) , and O2(+) with these compounds, and identification of the product ions and their distribution, are fundamental to their characterization and rapid, real-time trace analysis using SIFT-MS. METHODS: The chemical ionization of pure standards of 4-ethyloctanoic acid, 4-methyloctanoic acid, 4-ethylnonanoic acid, and 3-methylindole was carried out using the H3 O(+) , NO(+) , and O2(+) reagent ions of a V200(TM) selected ion flow tube-mass spectrometer...
July 28, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28751064/structure-interfacial-film-properties-and-thermal-fluctuations-of-microemulsions-as-seen-by-scattering-experiments
#17
REVIEW
Julian Oberdisse, Thomas Hellweg
The physics of microemulsions and in particular Dominique Langevin's contributions to the understanding of microemulsion structure and bending properties using scattering techniques are reviewed. Among the many methods used by her and her co-workers, we particularly emphasize optical techniques and small angle neutron scattering (SANS), but also neutron spin echo spectroscopy (NSE). The review is then extended to more recent studies of properties of microemulsions close to surfaces, using reflectometry and grazing-incidence small angle neutron scattering (GISANS)...
July 16, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28735885/surface-hydrodynamics-of-viscoelastic-fluids-and-soft-solids-surfing-bulk-rheology-on-capillary-and-rayleigh-waves
#18
REVIEW
Francisco Monroy
From the recent advent of the new soft-micro technologies, the hydrodynamic theory of surface modes propagating on viscoelastic bodies has reinvigorated this field of technology with interesting predictions and new possible applications, so recovering its scientific interest very limited at birth to the academic scope. Today, a myriad of soft small objects, deformable meso- and micro-structures, and macroscopically viscoelastic bodies fabricated from colloids and polymers are already available in the materials catalogue...
July 18, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28734304/temperature-dependence-of-the-translocation-time-of-polymer-through-repulsive-nanopores
#19
Meng-Bo Luo, Dessalegne A Tsehay, Li-Zhen Sun
The forced translocation of a polymer chain through repulsive nanopores was studied by using Langevin dynamics simulations. The polymer is in the compact globule state at low temperature and in the random coil state at high temperature. Simulation results show that the mean translocation time 〈τ〉 is highly dependent on the temperature T and the minimal 〈τ〉 is located near the coil-globule transition temperature. Moreover, the scaling behaviors 〈τ〉 ∼ N(α) and 〈τ〉 ∼ F(-δ) are studied, with N the polymer length and F the driving force inside the nanopore...
July 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28734293/the-stretching-force-on-a-tethered-polymer-in-pressure-driven-flow
#20
Kai Szuttor, Tamal Roy, Steffen Hardt, Christian Holm, Jens Smiatek
We use mesoscopic lattice-Boltzmann/molecular dynamics simulations to study the stretching behavior of a single tethered polymer in micro- and nanochannels. In particular, we are interested in the connection between fluid flow properties and the force on the polymer chain. An analytical expression for the stretching force is proposed, which linearly depends on the number of monomers and the boundary shear rate. In agreement with theory, the numerical findings reveal that the influence of hydrodynamic interactions can be ignored, which is also supported by results of additional Langevin dynamics simulations...
July 21, 2017: Journal of Chemical Physics
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