TEMPO-Modified Polymethacrylates as Mediators in Electrosynthesis: Influence of the Molecular Weight on Redox Properties and Electrocatalytic Activity.

Homogeneous catalysts ("mediators") are frequently employed in organic electrosynthesis to control selectivity. Despite their advantages, they can have a negative influence on the overall energy and mass balance if used only once or recycled inefficiently. Polymediators are soluble redox-active polymers applicable as electrocatalysts, enabling recovery by dialysis or membrane filtration. Using anodic alcohol oxidation as an example, we have demonstrated that TEMPO-modified polymethacrylates (TPMA) can act as efficient and recyclable catalysts. In the present work, the influence of the molecular size on the redox properties and the catalytic activity was carefully elaborated using a series of TPMAs with well-defined molecular weight distributions. Cyclic voltammetry studies show that the polymer chain length has a pronounced impact on the key-properties. Together with preparative-scale electrolysis experiments, an optimum size range was identified for polymediator-guided sustainable reaction control.

The guardians of the periodontium-sequential and differential expression of antimicrobial peptides during gingival inflammation. Results from in vivo and in vitro studies.

AIM: To evaluate the sequential and differential expression of a variety of antimicrobial peptides (AMPs) during the development of an experimentally induced gingivitis in humans. MATERIAL AND METHODS: In twenty healthy volunteers, gingival inflammation was induced by abstention from oral hygiene at 6 teeth. Bleeding on probing (BOP) and plaque index (PI) were assessed, and gingival biopsies and gingival crevicular fluid (GCF) were collected at 8 different time points (t0-t35). Gingival epithelial cells (GECs) were stimulated with various receptor agonists. In biopsies and GECs, mRNA expression of human beta-defensins (hBD-2, hBD-3), CC-chemokine ligand 20 (CCL20), S100A7/psoriasin (S100A7), and calgranulin A/B (S100A8, S100A9) was evaluated using real-time PCR, and protein profiles were measured by ELISA. Statistical analysis was performed using non-parametric tests. RESULTS: The clinical parameters BOP, PI and GCF increased over time (p < 0.0001). Tissue AMP mRNA expression was elevated, but at different and AMP-specific time points (p < 0.05). Protein analysis revealed a similar expression pattern for hBD-2 and CCL20 in GCF (p < 0.05). In GECs, multiple receptor stimulation was required to induce AMP gene expression (p < 0.0001). CONCLUSIONS: For the first time, this study showed the sequential and differential expression of AMPs during a developing inflammation in vivo providing further evidence for their role as guardians of a healthy periodontium.