Methylation of alkenes and methylbenzenes by dimethyl ether or methanol on acidic zeolites

The methylation of propene and toluene with dimethyl ether has been studied using both experimental and theoretical methods, and the results are compared with results obtained for methylation with methanol. The results indicate that the nature of the methylation reaction mechanisms is very similar for both methylation agents. Both experiment and theory show that dimethyl ether is a slightly more reactive methylating agent than methanol.     

Intracorneal Implantation of 3D Bioprinted Scaffolds Containing Mesenchymal Stromal Cells Using Femtosecond-Laser-Assisted Intrastromal Keratoplasty

Injury of the cornea is a complex biological process. Regeneration of the corneal stroma can be facilitated by the presence of mesenchymal stromal cells (MSCs) and application of tissue equivalents. A new tissue-engineering strategy for corneal stroma regeneration is presented using cellularized 3D bioprinted hydrogel constructs implanted into organ cultured porcine corneas using femtosecond laser-assisted intrastromal keratoplasty. The ex vivo cultured, MSC-loaded 3D bioprinted structures remain intact, support cell survival, and contain de novo synthesized extracellular matrix components and migrating cells throughout the observation period. At day 14 postimplantation, the cellularized tissue equivalents contain few or no cells, as demonstrated by optical coherence tomography imaging and immunofluorescent staining. This study successfully combines a laboratory-based method with modern, patient-care practice to produce a cell-laden tissue equivalent for corneal implantation. Optimal bioink composition and cellularization of tissue equivalents are essential in fine-tuning a method to promote the current technique as a future treatment modality.