The microrheology of viscoelastic fluids is obtained from rotational diffusion of optically anisotropic spherical colloidal probes, measured by depolarized dynamic light scattering. The storage and loss moduli obtained from the rotational mean squared displacement is in excellent agreement with those obtained from translational diffusion and by mechanical measurements. We also show that this method is applicable to samples with strong light scattering components. This extends the capabilities of the microrheological methods based on the diffusional motion of colloidal probes.
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http://dx.doi.org/10.1103/PhysRevLett.94.106001 | DOI Listing |
J Chem Phys
December 2024
Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
The reaction coefficient for hydrogen/deuterium (H/D) exchange and the diffusion of hydrated excess protons within amorphous solid water (ASW) are characterized as a function of temperature. For these experiments, water films are deposited on a Pt(111) substrate at 108 K, and reactions with pre-adsorbed hydrogen atoms produce hydrated protons. Upon heating, protons diffuse within the water, and H/D exchange occurs when they encounter D2O probe molecules deposited in the films.
View Article and Find Full Text PDFBiochem Biophys Res Commun
December 2024
Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13, W8, Sapporo, 060-8628, Japan; Department of Chemistry, Faculty of Science, Hokkaido University, N8, W5, Sapporo, 060-0810, Japan. Electronic address:
Bicelles, an artificial disk-shaped lipid bilayer, are commonly used for the structural and functional characterization of membrane-bound proteins in an environment similar to that in intracellular membranes. Because the dynamics of the lipids that constitute bicelles exert a significant impact on the structure and function of the inserted proteins, we investigated the mobility of lipid molecules in bicelles composed of DMPC (14:0 PC) and DHPC (06:0 PC) using solution NMR and MD calculations. C R relaxation experiments for the acyl groups demonstrated that increasing bicelle sizes limit the rotational diffusion of acyl chain H-C bonds in DMPC.
View Article and Find Full Text PDFJ Phys Condens Matter
December 2024
Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, Düsseldorf, 40225, GERMANY.
We study analytically the dynamics of an anisotropic particle subjected to different stochastic resetting schemes in two dimensions. The Brownian motion of shape-asymmetric particles in two dimensions results in anisotropic diffusion at short times, while the late-time transport is isotropic due to rotational diffusion. We show that the presence of orientational resetting promotes the anisotropy to late times.
View Article and Find Full Text PDFJ Med Case Rep
December 2024
Department of Internal Medicine, School of Medicine, College of Medicine and Health Science, University of Gondar, Gondar, Ethiopia.
Introduction: Traumatic obturator-type anterior dislocation of the hip with an ipsilateral subtrochanteric fracture is rarely encountered in clinical practice. This case presentation described a trauma patient with such a rare scenario.
Case Report: This paper reports a case of a 20-year-old Amhara ethnic male patient who had a traumatic anterior dislocation of the hip associated with an ipsilateral subtrochanteric femur fracture after a truck rolled over.
Imaging Neurosci (Camb)
March 2024
Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
We present MMORF-FSL's MultiMOdal Registration Framework-a newly released nonlinear image registration tool designed primarily for application to magnetic resonance imaging (MRI) images of the brain. MMORF is capable of simultaneously optimising both displacement and rotational transformations within a single registration framework by leveraging rich information from multiple scalar and tensor modalities. The regularisation employed in MMORF promotes local rigidity in the deformation, and we have previously demonstrated how this effectively controls both shape and size distortion, leading to more biologically plausible warps.
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