We investigate the general dependence of the thermal transport across nanoparticle-fluid interfaces using molecular dynamics computations. We show that the thermal conductance depends strongly both on the wetting characteristics of the nanoparticle-fluid interface as well as on the nanoparticle size. Strong nanoparticle-fluid interactions, leading to full wetting states in the host fluid, result in high thermal conductances and efficient interfacial transport of heat. Weak interactions result in partial drying or full drying states and low thermal conductances. The variation of the thermal conductance with particle size is found to depend on the fluid-nanoparticle interactions. Strong interactions coupled with large interfacial curvatures lead to optimum interfacial heat transport. This complex dependence can be modelled with an equation that includes the interfacial curvature as parameter. In this way we rationalise existing experimental and computer simulation results and show that the thermal transport across nanoscale interfaces is determined by the correlations of both interfacial curvature and nanoparticle-fluid interactions.

In recent years, sebum oil has been found to play a key role in the regulation of the hydration of the outermost layer of the skin, the stratum corneum. Understanding how a major component of the sebum oil, the triglyceride tri-cis-6-hexadecenoin (TG), interacts with water is an important step in gaining insight into the water regulation function of the sebum oil. Here we use molecular dynamics simulations to investigate the structural and interfacial properties of TG in bulk and at the air and water interface. Our model performs very well in reproducing experimental results, such as density, surface tensions and surface pressure area isotherms. We show that triglyceride molecules in the liquid phase assemble together, through the glycerol group, forming a single percolating network. TG-air interfaces orient the lipids with the interface enriched with the hydrophobic tails and the glycerol groups buried inside. When in contact with water, the TG molecules at the interface orient the glycerol group towards the water phase and adopt a characteristic trident conformation. Water is shown to penetrate the TG layer thanks to the interaction with the oxygen atoms of the TG molecules, which acts as a pathway for water diffusion. The activation energy for the passage of water is found to be ≈9.5kT at 310 K, showing that the layer is permeable to water diffusion.

Molecular mechanisms associated with human germ cell aplasia in infertile men remain undefined. Here we perform single-cell transcriptome profiling to highlight differentially expressed genes and pathways in each somatic cell type in testes of men with idiopathic germ cell aplasia. We identify immaturity of Leydig cells, chronic tissue inflammation, fibrosis, and senescence phenotype of the somatic cells, as well markers of chronic inflammation in the blood. We find that deregulated expression of parentally imprinted genes in myoid and immature Leydig cells, with relevant changes in the ratio of Lamin A/C transcripts and an active DNA damage response in Leydig and peritubular myoid cells are also indicative of senescence of the testicular niche. This study offers molecular insights into the pathogenesis of idiopathic germ cell aplasia.

Microsecond computations identify the pathways leading to the extraction of skin lipids by sebum triglycerides and the associated energetic costs.

Lipids are fundamental components of biological organisms and have important applications in the pharmaceutical, food and cosmetics industries. Thus, it is important that young students and the general public properly understand the basic properties of lipids and how these relate to their biological and industrial roles. Here, we use molecular dynamics computer simulations and a simple, safe and inexpensive popular hands-on activity, to communicate to participants why and how lipid molecules play a fundamental role in all living organisms and in our bodies. The activity is called "Fats' love-hate relationships", to highlight how the different parts of amphiphilic lipids interact with water. This "love-hate relationship" is vital to the biological functions of lipids and drives the formation of lipid structures that can be visualized at molecular scale with the computer simulations. The participants were encouraged to investigate the interactions between milk lipids and soap surfactants, creating beautiful complex artwork that they could then take home. The hands-on