In naval engineering and offshore industry,the fluid-structure interaction(FSI)problem is a very common problem,and water entry is a very representative *** hydroelasticity effects due to slamming are of great *** thi...
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In naval engineering and offshore industry,the fluid-structure interaction(FSI)problem is a very common problem,and water entry is a very representative *** hydroelasticity effects due to slamming are of great *** this paper,the water entry problem is simulated by the moving particle semi-implicit&finite element method(MPS-FEM)coupled *** MPS method is used for the fluid because it is very suitable for the violent free-surface *** structure domain is solved by the FEM method because of the maturity in solving structural motion and *** water entry of a rigid cylinder is numerically studied first and the results show good agreements with previous published *** that,variable analysis is conducted in the water entry simulation of an elastic cylinder,including the structural elasticity and impact velocity.
背景:帕金森病(Parkinson’s Disease, PD)是继阿尔茨海默病之后第二大神经退行性疾病。随着我国社会老龄化的加剧,帕金森病患者数量激增。认知障碍等非运动症状是帕金森病患者日常生活的主要影响因素,而临床上常规治疗帕金森病的方式对认知障碍几乎无效,其生物学相关机制也尚不明确。目的:总结归纳运动了干预对帕金森病患者认知障碍的作用以及潜在的生物学机制。方法:遵循系统综述和荟萃分析指南(Preferred Reporting Items for Systematic Reviews and Meta-Analysis, PRISMA),共纳入42篇文献。结果:这些研究是根据整体认知和特定认知域(执行功能、工作记忆、语言、记忆和视觉空间功能)进行分类的。并且,运动干预帕金森患者认知的生物学机制非常复杂。在分子水平上,有氧运动可增加血清神经营养因子水平、促进AMPA型谷氨酸受体表达和多巴胺分泌。在细胞水平上,对多巴胺能神经元有保护作用。在组织水平上,可增大海马体积和增强功能连接。结论:持续数月的有氧运动训练对帕金森病患者的认知有有益,但确切的生物学机制尚不清楚。未来的研究应探索帕金森病患者的个性化运动方案。Background: Parkinson’s disease (PD) is the second most common neurodegenerative disease following Alzheimer’s disease. As the population aging increases, the number of patients with PD is growing rapidly. Cognitive impairment and other non-motor symptoms have become a main factor in decline of quality of life in patients with PD. However, the current clinical treatments for PD have poor effectiveness on cognitive impairment, and the underlying biological mechanism is still unclear. Objectives: This study conducts a systematic review of the effects of exercise intervention on cognitive impairment in PD, and potential biological mechanism. Methods: Adhering to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, a total of forty-two studies were included. Results: These studies were classified based on whether they evaluated global cognition or specific cognitive domains such as executive functions, working memory, language, memory, and visuospatial function. Moreover, molecular, cellular, and systemic changes occur under the effect of exercise. At the molecular level, aerobic exercise is found to increase the serum level of neurotrophic factors, the expression of AMPA-type glutamate receptor, and the secretion of dopamine. At the cellular level, it offers a protective effect on dopaminergic neurons. At the systemic level, it is associated with enhanced hippocampus volume and functional connectivity. Conclusion: Several-month aer
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