Toxicity of diesel exhaust is related to the inhalation of nano-sized fractal-like aerosol aggregates. Their complex behavior (in comparison to spherical particles) should be taken into account in deposition modeling. The deposition of aerosol fractal-like aggregates in the model of a human nose was studied numerically for the flow rate corresponding to breathing conditions. The simplified geometry of the human nasal replica was implemented in the computational fluid dynamics (CFD) code (FLUENT) used for calculation of the three-dimensional airflow structure. A Brownian dynamic (BD) algorithm was applied for determination of the aggregates deposition in the nasal cavity during inhalation. These calculations were carried out for several populations of aggregates. The values of parameters used in the BD simulations for characterization of fractal-like aggregates, that is, fractal dimension (Df) and the radius of gyration (Rg), were in the range of 1.7-2.1 and 0.24-0.36 microm, respectively. These are the representative values for soot aggregates emitted from diesel engines. The results of computation show approximately 20% penetration of submicrometer aggregates through the nose and a weak dependence of deposition efficiency on Df and Rg values. The proposed methodology may lead to a more realistic description of deposition of nonspherical aerosol particles in the respiratory system. A more sophisticated approach for description of fractal-like aggregates dynamics is suggested for future studies.
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Biophys J
December 2024
Institut für Röntgenphysik, Göttingen, Germany. Electronic address:
Synaptic vesicle clusters or pools are functionally important constituents of chemical synapses. In the so-called reserve and the active pools, neurotransmitter-loaded synaptic vesicles (SVs) are stored and conditioned for fusion with the synaptic membrane and subsequent neurotransmitter release during synaptic activity. Vesicle clusters can be considered as so-called membraneless compartments, which form by liquid-liquid phase separation.
View Article and Find Full Text PDFSci Rep
October 2024
Department of Physics, Norwegian University of Science and Technology, 7491, Trondheim, Norway.
J Chem Phys
July 2024
Faculty of Mechanical Engineering, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Patchy nanocubes are intriguing materials with simple shapes and space-filling and multidirectional bonding properties. Previous studies have revealed various mesoscopic structures such as colloidal crystals in the solid regime and rod-like or fractal-like aggregates in the liquid regime of the phase diagram. Recent studies have also shown that mesoscopic structural properties, such as an average cluster size M and orientational order, in amphiphilic nanocube suspensions are associated with macroscopic viscosity changes, mainly owing to differences in cluster shape among patch arrangements.
View Article and Find Full Text PDFSoft Matter
May 2024
School of Physics and Astronomy and the Center for Physics and Chemistry of Living Systems, Tel Aviv University, Israel.
We investigate a system of co-oriented active particles interacting only hydrodynamic and steric interactions in a two-dimensional fluid. We offer a new method of calculating the flow created by any active particle in such a fluid, focusing on the dynamics of flow fields with a high-order spatial decay, which we analyze using a geometric Hamiltonian. We show that when the particles are oriented and the flow has a single, odd power decay, such systems lead to stable, fractal-like aggregation, with the only exception being the force dipole.
View Article and Find Full Text PDFCarbohydr Res
November 2023
Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560 012, India. Electronic address:
Anthracenemethyl glucosides, that possess ethylene glycol linkers connecting the glucoside with anthracene moiety, are studied herein. Koenigs-Knorr glycosylation of ethylene glycol-tethered anthracene with acetobromo glucose, followed by removal of the protecting groups, lead to the facile formation of the target glucosides. Aq.
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