Distribution of low quality filtering facepiece respirators during the COVID-19 pandemic: an independent analysis of the situation in Switzerland.

Background: SARS-CoV-2 is a respiratory virus. Transmission occurs by droplets, contact and aerosols. In medical settings, filtering facepiece (FFP) respirators are recommended for use by personnel exposed to aerosol-generating procedures.

ATRP-based synthesis and characterization of light-responsive coatings for transdermal delivery systems.

The grafting of poly(hydroxyethylmethacrylate) on polymeric porous membranes via atom transfer radical polymerization (ATRP) and subsequent modification with a photo-responsive spiropyran derivative is described. This method leads to photo-responsive membranes with desirable properties such as light-controlled permeability changes, exceptional photo-stability and repeatability of the photo-responsive switching. Conventional track etched polyester membranes were first treated with plasma polymer coating introducing anchoring groups, which allowed the attachment of ATRP-initiator molecules on the membrane surface.

Preparation of light-responsive membranes by a combined surface grafting and postmodification process.

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is presented. The polymerization from the membrane surface is induced by plasma treatment of the membrane, followed by reacting the membrane surface with a methanolic solution of 2-hydroxyethyl methacrylate (HEMA). Special attention is given to the process parameters for the plasma treatment prior to the polymerization on the surface.

Light-responsive caffeine transfer through porous polycarbonate.

Light-responsive membranes based on a porous polycarbonate (PC) matrix were developed by surface functionalization with spirobenzopyran (SP)-containing polymers. The surface modification was generated by plasma-induced surface graft polymerization. Mass transfer rates of caffeine through these membranes were found to be up to eight times higher under UV irradiation than at daylight.