The Lévy walk is a popular and more 'physical' model to describe the phenomena of superdiffusion, because of its finite velocity. The movements of particles are under the influence of external potentials at almost any time and anywhere. In this paper, we establish a Langevin system coupled with a subordinator to describe the Lévy walk in a time-dependent periodic force field. The effects of external force are detected and carefully analyzed, including the nonzero first moment (even though the force is periodic), adding an additional dispersion on the particle position, a consistent influence on the ensemble- and time-averaged mean-squared displacement, etc. Besides, the generalized Klein-Kramers equation is obtained, not only for the time-dependent force but also for the space-dependent one.
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http://dx.doi.org/10.1103/PhysRevE.103.012136 | DOI Listing |
J Chem Inf Model
January 2025
Department of Biochemistry, University of Oxford, Oxford OX1 3QU, U.K.
Sugars are ubiquitous in biology; they occur in all kingdoms of life. Despite their prevalence, they have often been somewhat neglected in studies of structure-dynamics-function relationships of macromolecules to which they are attached, with the exception of nucleic acids. This is largely due to the inherent difficulties of not only studying the conformational dynamics of sugars using experimental methods but indeed also resolving their static structures.
View Article and Find Full Text PDFACS Nano
January 2025
Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
The iron-regulated surface determinant protein B (IsdB) has recently been shown to bind to toll-like receptor 4 (TLR4), thereby inducing a strong inflammatory response in innate immune cells. Currently, two unsolved questions are (i) What is the molecular mechanism of the IsdB-TLR4 interaction? and (ii) Does it also play a role in nonimmune systems? Here, we use single-molecule experiments to demonstrate that IsdB binds TLR4 with both weak and extremely strong forces and that the mechanostability of the molecular complex is dramatically increased by physical stress, sustaining forces up to 2000 pN, at a loading rate of 10 pN/s. We also show that TLR4 binding by IsdB mediates time-dependent bacterial adhesion to endothelial cells, pointing to the role of this bond in cell invasion.
View Article and Find Full Text PDFLangmuir
January 2025
R&D - Analytical Science Research, Kao Corporation, 1334 minato, Wakayama, Wakayama 640-8580, Japan.
The adsorption behavior of an anionic surfactant, hydroxy alkane sulfonate with an alkyl chain length of 18 (C18HAS), from its hard water solution onto a mica surface and resulting lubrication properties were investigated. Because of the double chain-like chemical structure and aggregation behavior, C18HAS formed vesicles in hard water, which adsorbed onto a negatively charged mica surface via cation (Ca) bridging and then transformed into a bilayer film. The number of bilayers formed on the surface was evaluated by force curve measurements using an atomic force microscope (AFM), and the results showed a time-dependent increase of the number of adsorbed bilayers.
View Article and Find Full Text PDFJ Transl Med
January 2025
Dental School, The University of Western Australia, 17 Monash Avenue, Nedlands, WA, 6009, Australia.
Background: Treatment of deep carious lesions poses significant challenges in dentistry, as complete lesion removal risks compromising pulp vitality, while selective removal often reduces the longevity of restorations. Herein, we propose a minimally invasive approach using High-Intensity Focused Ultrasound (HIFU) for microscale removal of carious dentine. Concurrently, HIFU's antimicrobial effects against associated cariogenic biofilms and the corresponding thermal and biological impacts on surrounding tissues were investigated.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
Detection and attribution (DA) studies are cornerstones of climate science, providing crucial evidence for policy decisions. Their goal is to link observed climate change patterns to anthropogenic and natural drivers via the optimal fingerprinting method (OFM). We show that response theory for nonequilibrium systems offers the physical and dynamical basis for OFM, including the concept of causality used for attribution.
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