Products from enzymic oxidation of 2′,4,4′-trihydroxychalcone: structural reconsiderations

The enzymic products from peroxidase-catalysed oxidation of 2′,4,4′-trihydroxychalcone react with diphenylsulphide to form diastereoisomers of 4′,6-dihydroxy-2-(α-hydroxybenzyl)-coumaranone, consistent with their previously assigned dioxetane structure.     

Temperature and strain discrimination using a single tilted fibre Bragg grating

A fibre optic sensor capable of discriminating between temperature and strain, using a single fibre Bragg grating, is presented. The technique exploits the core-cladding mode coupling of a tilted fibre Bragg grating (TFBG). The core and cladding modes exhibit different thermal sensivities, while the strain sensivities are approximately equal. Monitoring the core-core mode coupling resonance and the core-cladding mode coupling resonance of the TFBG spectrum allows the separation of the temperature and strain induced wavelength shifts.