X-ray photon correlation spectroscopy was employed in a surface standing wave geometry in order to resolve the thermally driven in-plane dynamics at both the surface/vacuum (top) and polymer/polymer (bottom) interfaces of a thin polystyrene (PS) film on top of Poly(4-bromo styrene) (PBrS) and supported on a Si substrate. The top vacuum interface shows two relaxation modes: one fast and one slow, while the buried polymer-polymer interface shows a single slow mode. The slow mode of the top interface is similar in magnitude and wave vector dependence to the single mode of the buried interface. The dynamics are consistent with a low-viscosity mixed layer between the PS and PBrS and coupling of the capillary wave fluctuations between this layer and the PS.
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http://dx.doi.org/10.1103/PhysRevE.74.010602 | DOI Listing |
J Am Chem Soc
January 2025
Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States.
Direct translocation of RNA with secondary structures using single-molecule electrophoresis through protein nanopores shows significant fluctuations in the measured ionic current, in contrast to unstructured single-stranded RNA or DNA. We developed a multiscale model combining the oxRNA model for RNA with the 3-dimensional Poisson-Nernst-Planck formalism for electric fields within protein pores, aiming to map RNA conformations to ionic currents as RNA translocates through three protein nanopores: α-hemolysin, CsgG, and MspA. Our findings reveal three distinct stages of translocation (pseudoknot, melting, and molten globule) based on contact maps and current values.
View Article and Find Full Text PDFAnal Chim Acta
January 2025
College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China. Electronic address:
Background: The rapid and sensitive detection of nitrite is important to human health protection due to its carcinogenic and teratogenic risks with excessive intake. The Griess assay is widely applied for the design of nitrite detection system. However, its relatively slow reaction kinetics and sole colorimetry mode might limit it's the sensitivity and practical application.
View Article and Find Full Text PDFJ Commun Disord
December 2024
MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK.
Objectives: The objectives of this study were to evaluate the relationships between auditory processing, speech discrimination, and listening and communication abilities in children diagnosed with auditory neuropathy spectrum disorder (ANSD) compared to those with normal hearing.
Methods: This was a case-control study involving seventeen participants with a diagnosis of ANSD who used spoken language as their primary mode of communication and wore hearing aids or were unaided and 21 normally hearing controls. All underwent a battery of behavioural measures of hearing, speech perception and auditory processing skills.
Nat Mater
January 2025
Department of Fundamental Engineering, Institute of Industrial Science, The University of Tokyo, Tokyo, Japan.
Supercooled liquids display sluggish dynamics, often attributed to their structural characteristics, yet the underlying mechanism remains elusive. Here we conduct numerical investigations into the structure-dynamics relationship in model glass-forming liquids, with a specific focus on an elementary particle rearrangement mode known as the 'T1 process'. We discover that the ability of a T1 process to preserve glassy structural order before and after is pivotal towards determining a liquid's fragility-whether it exhibits super-Arrhenius-like or Arrhenius-like behaviour.
View Article and Find Full Text PDFPharmaceutics
November 2024
School of Pharmacy, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA.
Skin inflammation represents a hallmark of many skin conditions, from psoriasis to eczema. Here, we present a novel microemulsion formulation for delivering a low dose of potent immunosuppressant, tacrolimus, to the skin for local inflammation control. The efficacy of topically delivered tacrolimus in controlling skin inflammation can be enhanced by packaging it into microemulsions.
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