A single-wire corona unipolar aerosol charger with a sheath air to avoid particle loss was designed and experimental charging efficiencies were obtained at a fixed aerosol flow rate of 1 L/min using monodisperse silver nanoparticles of 2.5 to 20 nm in diameter. The charger has a cylindrical casing of 30 mm in inner diameter in which a gold wire of 50 µm in diameter and 2 mm in length is used as the discharge electrode. A two-dimensional (2-D) numerical model was developed to predict nanoparticle charging efficiency in the unipolar charger. Laminar flow field was solved by using the Semi-Implicit Method for Pressure Linked Equations (SIMPLER method), while electric potential and ion concentration fields were solved on the basis of Poisson and convection-diffusion equations, respectively. The charged particle concentration fields and charging efficiencies were then calculated on the basis of the convection-diffusion equation in which ion-particle combination coefficient was calculated by Fuchs diffusion charging theory (Fuchs, N. A. (1963). On the Stationary Charge Distribution on Aerosol Particles in a Bipolar Ionic Atmosphere. Geophys. Pura. Appl., 56:185-193). Good agreement between predicted and experimental extrinsic charging efficiencies was obtained. Numerical results showed the advantage of using sheath air to minimize charged particle loss and indicated the location where major charged particle loss occurred. It is expected that the present model can be used to facilitate the design of more efficient corona-wire unipolar charger in the future.
Pb1-xSrx (Zr0.53Ti0.47) O3 (PSZT) thin films have been fabricated on Pt/Ti/SiO2/Si substrate by a sol–gel method combined with a rapid thermal annealing process. The microstructure analysis of the thin films showed that the orientation ratio of (111) was 0.304,0.475 and 0.849 with x=0, 0.03, 0.08. The dielectric measurement suggested that the addition of Sr in Pb(Zr0.53Ti0.47) O3(PZT) thin films greatly improved the dielectric properties of PZT thin films. The dielectric constant for PZT thin films at a frequency of 2 kHz was 648,which was increased to 1239 when 3%at Sr was doped. Meanwhile, the dissipation factor was only increased from 0.02 to 0.03. Three kinds of piezoelectric micro-sensors have been prepared based on PSZT thin films and the sensing sensitivity of 0.017pc/uN, 0.033pc/uN, and 0.011pc/uN were realized as x increased, respectively. It indicated that micro-sensors with PSZT0.03 thin films showed better sensing property than other two.
Background: Hyaluronan (HA) metabolism by chondrocytes is essential for cartilage development and homeostasis. However, the function of circular RNAs (circRNAs)in HA metabolism is limited. In this study, we profiled the role of the novel HA-related circRNA circHYBID in the progression of osteoarthritis.Methods: The function of circHYBID in HA metabolism in chondrocytes was investigated using gain-of-function experiments. The mechanism of HA-binding protein involved in hyaluronan depolymerization (HYBID) was confirmed through bioinformatics analysis and luciferase assays. The expression correlation of the circHYBID–hsa-miR-29b-3p–transforming growth factor (TGF)-β1 axis was examined by qRT-PCR and western blotting. CircHYBID, TGF-β1, and HA levels in cartilage samples were evaluated using immunohistochemistry. ELISA assay was used to assess HA accumulation in chondrocyte supernatant.Results: CircHYBID expression was significantly downregulated in damaged cartilage samples comparing with that in the corresponding intact cartilage samples. CircHYBID expression was inversely correlated with the Mankin score and positively correlated with HA expression. Interleukin-1β stimulation in chondrocytes downregulated circHYBID expression and decreased HA accumulation. Gain-of-function experiments revealed that circHYBID overexpression in chondrocytes increased HA accumulation by regulating HA synthase 2 and HYBID expression. Further mechanism analysis illustrated that circHYBID upregulated TGF-β1 expression by sponging hsa-miR-29b-3p. Conclusions: Our results describe a novel HA-related circRNA that could promote the synthesis and accumulation of HA. The circHYBID–hsa-miR-29b-3p–TGF-β1 axis may play a powerful regulatory role in HA metabolism and Osteoarthritis (OA) progression. Thus, these findings will provide new perspectives for studies on OA pathogenesis, and circHYBID may serve as a potential target for OA therapy.
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