323 research outputs found
Classical solutions to a BGK-type model relaxing to the isentropic gas dynamics
In this paper, we consider a BGK-type kinetic model relaxing to the
isentropic gas dynamics in the hydrodynamic limit. We introduce a linearization
of the equation around the global equilibrium. Then we prove the global
existence of classical solutions with an exponential convergence rate toward
the equilibrium state in the periodic domain when the initial data is a small
perturbation of the global equilibrium
Determination of equilibrium parameters of the Marle model for polyatomic gases
The BGK model is a relaxation-time approximation of the celebrated Boltzmann
equation, and the Marle model is a direct extension of the BGK model in a
relativistic framework. In this paper, we introduce the Marle model for
polyatomic gases based on the J\"{u}ttner distribution devised in [Ann. Phys.,
377, (2017), 414--445], and show the existence of a unique set of equilibrium
parameters of the J\"{u}ttner distribution
Stationary solutions to the relativistic BGK model for gas mixtures in a slab
In a recent paper [16], the authors proposed a BGK model for relativistic gas
mixtures based on the Marle-type approximation, which satisfies the fundamental
kinetic properties: non-negativity of distribution functions, conservation
laws, H-theorem, and indifferentiability principle. In this paper, we are
concerned with the stationary problems to the relativistic BGK model for gas
mixtures in slab geometry. We establish the existence of a unique mild solution
with the fixed inflow boundary data when the collision frequencies for each
species are sufficiently small.Comment: 17 paga
Existence of an unbounded branch of the set of solutions for Neumann problems involving the p(x)-Laplacian
Effect of 660 nm Light-Emitting Diode on the Wound Healing in Fibroblast-Like Cell Lines
Light in the red to near-infrared (NIR) range (630–1000 nm), which is generated using low energy laser or light-emitting diode (LED) arrays, was reported to have a range of beneficial biological effects in many injury models. NIR via a LED is a well-accepted therapeutic tool for the treatment of infected, ischemic, and hypoxic wounds as well as other soft tissue injuries in humans and animals. This study examined the effects of exposure to 660 nm red LED light at intensities of 2.5, 5.5, and 8.5 mW/cm2 for 5, 10, and 20 min on wound healing and proliferation in fibroblast-like cells, such as L929 mouse fibroblasts and human gingival fibroblasts (HGF-1). A photo illumination-cell culture system was designed to evaluate the cell proliferation and wound healing of fibroblast-like cells exposed to 600 nm LED light. The cell proliferation was evaluated by MTT assay, and a scratched wound assay was performed to assess the rate of migrating cells and the healing effect. Exposure to the 660 nm red LED resulted in an increase in cell proliferation and migration compared to the control, indicating its potential use as a phototherapeutic agent
5′-Triphosphate-RNA-independent activation of RIG-I via RNA aptamer with enhanced antiviral activity
RIG-I is a cytosolic receptor for non-self RNA that mediates immune responses against viral infections through IFNα/β production. In an attempt to identify novel tools that modulate IFNα/β production, we used SELEX technology to screen RNA aptamers that specifically target RIG-I protein. Most of the selected RIG-I aptamers contained polyU motifs in the second half regions that played critical roles in the activation of RIG-I-mediated IFNβ production. Unlike other known ligands, RIG-I aptamer bound and activated RIG-I in a 5′-triphosphate-independent manner. The helicase and RD domain of RIG-I were used for aptamer binding, but intact RIG-I protein was required to exert aptamer-mediated signaling activation. Furthermore, replication of NDV, VSV and influenza virus in infected host cells was efficiently blocked by pre- or post-treatment with RIG-I aptamer. Based on these data, we propose that RIG-I aptamer has strong potential to be an antiviral agent that specifically boosts the RIG-I-dependent signaling cascade
Percutaneous radiofrequency ablation for hepatic tumors: factors affecting baseline impedance
PurposeWe aimed to evaluate factors that affect baseline impedance of percutaneous radiofrequency ablation.MethodsIn this retrospective study, we analyzed 51 patients with 55 hepatic tumors from November 2015 until April 2018. We measured the baseline impedance nine times with three adjustable tip sizes (2 cm, 2.5 cm, 3 cm) and three different pad locations (two pads attached on the thigh, four on the thigh, two on the back). The first roll-off time was measured with two grounding pads attached on the back. Body mass index, cirrhotic or non-cirrhotic liver parenchyma, previous procedure, tumor location, artificial ascites, active tip size, and the pad location were evaluated as potential factors affecting baseline impedance using the Mann–Whitney U test, t-test and analysis of variance test.ResultsComplete radiofrequency ablation was achieved in 51 patients. Body mass index (p = 0.897), cirrhotic or non-cirrhotic liver parenchyma (p = 0.767), previous procedure (p = 0.957), tumor location (p = 0.906), and artificial ascites (p = 0.882) did not significantly affect baseline impedance. Grounding pads located on the back showed the lowest baseline impedance (p < 0.001). Increase in active tip size showed gradual decrease in baseline impedance (p = 0.016).ConclusionThe factors affecting baseline impedance were the pad location and the tip size. Positioning pads on the back lowers the baseline impedance and can shorten the first roll-off time, ultimately resulting in reduced total ablation time
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