The potential of mean force of nitrous oxide in a 1,2-dimyristoylphosphatidylcholine lipid bilayer

Silk fibroin porous scaffolds by N2O foaming

Silk fibroin has acquired increasing interest for biomedical applications, and namely for the fabrication of scaffolds for tissue engineering, because of its highly positive biological interaction and the possibility to adapt the material to several application requirements by adopting different fabrication methods, in order to make films, sponges, fibers, nets or gels with predictable degradation times. For tissue engineering, in most cases porous scaffolds are required, in some cases possibly in situ forming and therefore fabricated in mild body-compatible conditions. In this work, we present a novel one-step method for the preparation of silk fibroin foams starting from water solutions and using low-pressure nitrous oxide gas as foaming agent. This foaming technique allows preparing fibroin porous scaffolds with easily tunable porosity, in mild processing conditions with the use of a relatively inert foaming agent saturating a fibroin water solution, that could be occasionally injected through a thin needle in the implantation site where expansion and foaming would occur. Optimal foaming processing conditions have been investigated, and the prepared foams have been characterized with Fourier Transform Infrared Spectroscopy (FTIR) compressive mechanical and rheological properties measurements, and by scanning electron microscopy and microCT.

Gas-phase and transpiration-driven mechanisms for volatilization through wetland macrophytes

Natural and constructed wetlands have gained attention as potential tools for remediation of shallow sediments and groundwater contaminated with volatile organic compounds (VOCs). Wetland macrophytes are known to enhance rates of contaminant removal via volatilization, but the magnitude of different volatilization mechanisms, and the relationship between volatilization rates and contaminant physiochemical properties, remain poorly understood. Greenhouse mesocosm experiments using the volatile tracer sulfur hexafluoride were conducted to determine the relative magnitudes of gas-phase and transpiration-driven volatilization mechanisms. A numerical model for vegetation-mediated volatilization was developed, calibrated with tracer measurements, and used to predict plant-mediated volatilization of common VOCs as well as quantify the contribution of different volatilization pathways. Model simulations agree with conclusions from previous work that transpiration is the main driver for volatilization of VOCs, but also demonstrate that vapor-phase transport in wetland plants is significant, and can represent up to 50% of the total flux for compounds with greater volatility like vinyl chloride.