Experimental validation of a phase-field model to predict coarsening dynamics of lipid domains in multicomponent membranes

Membrane phase-separation is a mechanism that biological membranes often use to locally concentrate specific lipid species in order to organize diverse membrane processes. Phase separation has also been explored as a tool for the design of liposomes with heterogeneous and spatially organized surfaces. These “patchy” liposomes are promising platforms for delivery purposes, however their design and optimization through experimentation can be expensive and time-consuming. We developed a computationally efficient method based on the surface Cahn–Hilliard phase-field model to complement experimental investigations in the design of patchy liposomes. The method relies on thermodynamic considerations to set the initial state for numerical simulations. We show that our computational approach delivers not only qualitative pictures, but also accurate quantitative information about the dynamics of the membrane organization. In particular, the computational and experimental results are in excellent agreement in terms of lipid domain area fraction, total lipid domain perimeter over time and total number of lipid domains over time for two different membrane compositions (DOPC:DPPC with a 2:1 M ratio with 20% Chol and DOPC:DPPC with a 3:1 M ratio with 20% Chol). Thus, the computational phase-field model informed by experiments has a considerable potential to assist in the design of liposomes with spatially organized surfaces, thereby containing the cost and time required by the design process.     

Supportive family relationships and adolescent health in the socio-cultural context of Iran: a qualitative study

Parents have a critical role in adolescent health. The association of adolescents'' perceptions of family relationships with adolescent health was investigated using a sample of 67 female adolescents who participated in eight focus group discussions, utilising a purposeful sampling method. All tape-recorded data were fully transcribed and content analysis was performed. Three themes were identified, namely emotional support, responsible parents and well-informed parents. With regard to some of the challenges in Iranian adolescents'' relationships with their parents, it is necessary to educate parents to be alert to their role in adolescent health.