To investigate the force model and motion law of oil droplets in water near the wetted wall, oil droplets with R 1 = 0.29–0.62 mm and oil films with R 2 = 1–6 mm are solved numerically. In addition to buoyancy, flow resistance, and added mass force, the film-induced force triggered by the wetted wall constraint is also introduced into the force model. The drainage process is described using the Stokes–Reynolds equation, and the Young–Laplace equation is used to calculate the pressure within the water film. The results show that the force model can be coupled with the Stokes–Reynolds–Young–Laplace model equation to better describe the drainage dynamics near the wetted wall. The pressure distribution law is closely related to the shape of the water film, especially when the oil–water interface is in the shape of a dimple, which can lead to the formation of negative pressure zones within the water film. The maximum pressure first grows in an exponential, then logarithmic pattern and eventually approaches the equivalent Laplace pressure. Around the critical size, the direction of the film-induced force changes and the form of action switches between driving and drag forces. The film-induced force's dominant effect is strongest when the curvature radius of the oil film is comparable to the droplet size.
Chen Xu,Tanran Chang,Yaqi Du,Chaohui Yu,Xin Tan,Xiangdong Li
Cannabidiol (CBD) exhibits significant efficacy in mental and inflammatory diseases. Several studies have recently reported on the rapid antidepressant-like effects of CBD, suggesting that CBD is a potential anti-depressant or anti-stress drug. However, CBD is mainly administered orally or by inhalation with poor bioavailability, resulting in high costs. We aim to explore the efficacy of long-term periodic administration of CBD in chronic mild stress (CMS) via two routes and its pharmacokinetics. We treated ICR mice with CBD administered orally and intravenously and then determined the kinetic constants. A single bolus intravenous injection of CBD resulted in a half-life of 3.9 h, mean residence time of 3.3 h, and oral bioavailability of about 8.6%. The antidepressant-like effects of periodically administered CBD on the chronic mild stress mouse model are evaluated. Results demonstrated that such treatment at a high dose of 100 mg/kg CBD (p.o.) or a low dose of 10 mg/kg CBD (i.v.), elicited significant antidepressant-like behavioral effects in forced swim test, following increased mRNA expression of brain-derived neurotrophic factor (BDNF) and synaptophysin in the prefrontal cortex and the hippocampus. Our findings are expected to provide a reference for the development of intravenous antidepressant formulations of CBD.
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