Laccase mediator systems for eco-friendly production of medium-density fiberboard (MDF) on a pilot scale: physicochemical analysis of the reaction mechanism.

Increasing prices of petrochemical resins and possible harmful formaldehyde emissions from conventionally produced wood composites have resulted in increased interest in enzymatic binder systems as environmentally friendly alternatives for gluing lignocellulosic products. In this study, laccase mediator systems (LMSs) were used to activate lignin on wood fiber surfaces in the pilot-scale production of medium-density fiberboard (MDF) using a dry process. Three different mediators were applied: 4-hydroxybenzoic acid (HBA), 1-hydroxybenzotriazole (HBT), and acetosyringone (AS) of which HBA performed best.

Elevated expression of genes assigned to NF-kappaB and apoptotic pathways in human periodontal ligament fibroblasts following mechanical stretch.

There is growing evidence that apoptosis involves the nuclear transcription factor NF-kappaB in conjunction with related genes. However, in the context of mechanical orthodontic forces, force-sensing target genes assigned to pathways of NF-kappaB and apoptosis have not been fully characterised. To contribute to the identification of putative target genes, we used cDNA arrays specific for NF-kappaB and apoptotic pathways and analysed elevated gene expression in primary human periodontal ligament fibroblasts (PDL-F) after a 6 h application of mechanical force.