Disjoining Potential and Spreading of Thin Liquid Layers in the Diffuse Interface Model Coupled to Hydrodynamics

The hydrodynamic phase field model is applied to the problem of film spreading on a solid surface. The disjoining potential, responsible for modification of the fluid properties near a three-phase contact line, is computed from the solvability conditions of the density field equation with appropriate boundary conditions imposed on the solid support. The equation describing the motion of a spreading film are derived in the lubrication approximation. In the case of quasi-equilibrium spreading, is shown that the correct sharp-interface limit is obtained, and sample solutions are obtained by numerical integration. It is further shown that evaporation or condensation may strongly affect the dynamics near the contact line, and accounting for kinetic retardation of the interphase transport is necessary to build up a consistent theory.Comment: 14 pages, 5 figures, to appear in PR

International exercise recommendations in older adults (ICFSR): expert consensus guidelines

The human ageing process is universal, ubiquitous and inevitable. Every physiological function is being continuously diminished. There is a range between two distinct phenotypes of ageing, shaped by patterns of living-experiences and behaviours, and in particular by the presence or absence of physical activity (PA) and structured exercise (i.e., a sedentary lifestyle). Ageing and a sedentary lifestyle are associated with declines in muscle function and cardiorespiratory fitness, resulting in an impaired capacity to perform daily activities and maintain independent functioning. However, in the presence of adequate exercise/PA these changes in muscular and aerobic capacity with age are substantially attenuated. Additionally, both structured exercise and overall PA play important roles as preventive strategies for many chronic diseases, including cardiovascular disease, stroke, diabetes, osteoporosis, and obesity; improvement of mobility, mental health, and quality of life; and reduction in mortality, among other benefits. Notably, exercise intervention programmes improve the hallmarks of frailty (low body mass, strength, mobility, PA level, energy) and cognition, thus optimising functional capacity during ageing. In these pathological conditions exercise is used as a therapeutic agent and follows the precepts of identifying the cause of a disease and then using an agent in an evidence-based dose to eliminate or moderate the disease. Prescription of PA/structured exercise should therefore be based on the intended outcome (e.g., primary prevention, improvement in fitness or functional status or disease treatment), and individualised, adjusted and controlled like any other medical treatment. In addition, in line with other therapeutic agents, exercise shows a dose-response effect and can be individualised using different modalities, volumes and/or intensities as appropriate to the health state or medical condition. Importantly, exercise therapy is often directed at several physiological systems simultaneously, rather than targeted to a single outcome as is generally the case with pharmacological approaches to disease management. There are diseases for which exercise is an alternative to pharmacological treatment (such as depression), thus contributing to the goal of deprescribing of potentially inappropriate medications (PIMS). There are other conditions where no effective drug therapy is currently available (such as sarcopenia or dementia), where it may serve a primary role in prevention and treatment. Therefore, this consensus statement provides an evidence-based rationale for using exercise and PA for health promotion and disease prevention and treatment in older adults. Exercise prescription is discussed in terms of the specific modalities and doses that have been studied in randomised controlled trials for their effectiveness in attenuating physiological changes of ageing, disease prevention, and/or improvement of older adults with chronic disease and disability. Recommendations are proposed to bridge gaps in the current literature and to optimise the use of exercise/PA both as a preventative medicine and as a therapeutic agent.This article was supported in part by the CIBER of Frailty and Healthy Aging (CIBERFES), ISCIII, Spain and the National Institute on Aging, NIH, USA. A.G.-H. is a Miguel Servet Fellow (Instituto de Salud Carlos III - CP18/0150)