We designed a series of porous graphene as the separation membrane of H 2 /N 2 . The selectivity and permeability could be controlled by drilling various nanopores with different shapes and sizes. The mechanisms of hydrogen and nitrogen to permeate through the porous graphene are different. The small nanopore (pore-11) can only allow the hydrogen molecules to permeate due to the size restriction. In the systems of bigger nanopores (e.g., pore-13, pore-14, etc.), where the pore size is big enough to allow nitrogen molecules to permeate without any restriction, we observed more permeation events of nitrogen than that of hydrogen molecules. The reason is that the van der Waals interactions with the graphene membrane make the nitrogen molecules accumulate on the surface of graphene. When the pore size further increases, the flow of hydrogen molecules exhibits the linear dependence on the pore area, while there is no obvious correlation between the flow of nitrogen molecules and the pore area.
In order to enhance the bioavailability of poorly water-soluble curcumin, solution-enhanced dispersion by supercritical carbon dioxide (CO
2
) (SEDS) was employed to prepare curcumin nanoparticles for the first time. A 2
4
full factorial experiment was designed to determine optimal processing parameters and their influence on the size of the curcumin nanoparticles. Particle size was demonstrated to increase with increased temperature or flow rate of the solution, or with decreased precipitation pressure, under processing conditions with different parameters considered. The single effect of the concentration of the solution on particle size was not significant. Curcumin nanoparticles with a spherical shape and the smallest mean particle size of 325 nm were obtained when the following optimal processing conditions were adopted: P =20 MPa, T =35°C, flow rate of solution =0.5 mL·min
−1
, concentration of solution =0.5%. Fourier transform infrared (FTIR) spectroscopy measurement revealed that the chemical composition of curcumin basically remained unchanged. Nevertheless, X-ray powder diffraction (XRPD) and thermal analysis indicated that the crystalline state of the original curcumin decreased after the SEDS process. The solubility and dissolution rate of the curcumin nanoparticles were found to be higher than that of the original curcumin powder (approximately 1.4 μg/mL vs 0.2 μg/mL in 180 minutes). This study revealed that supercritical CO
2
technologies had a great potential in fabricating nanoparticles and improving the bioavailability of poorly water-soluble drugs.
Calcins are a new and expanding family of ryanodine receptor agonists found in scorpion venom. Xiao and colleagues characterize the structure–function relationships of all known calcins and show both similarities and differences in their form and function.
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