Attempted ignition of petrol vapour by lit cigarettes and lit cannabis resin joints.

A recent murder enquiry prompted experimentation to confirm and visually demonstrate that lit cigarettes are not a viable source of ignition of petrol vapour. In addition, tests comprising the attempted ignition of petrol vapour using hot and smouldering cannabis resin were also undertaken. A series of experiments was also designed to recreate circumstances specific to the crime under investigation by undertaking cigarette/joint ignition tests involving a mannequin clothed in a cotton garment onto which petrol was applied.

Synthesis and recovery characteristics of branched and grafted PNIPAAm-PEG hydrogels for the development of an injectable load-bearing nucleus pulposus replacement.

A family of injectable poly(N-isopropyl acrylamide) (PNIPAAm) copolymer hydrogels has been fabricated in order to tune mechanical properties to support load-bearing function and dimensional recovery for possible use as load-bearing medical devices, such as a nucleus pulposus replacement for the intervertebral disc. PNIPAAm-polyethylene glycol (PEG) copolymers were synthesized with varying hydrophilic PEG concentrations as grafted or branched structures to enhance dimensional recovery of the materials. Polymerizations were confirmed with attenuated total reflectance-Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy studies.

Triplet energies and the singlet oxygen quenching mechanism for 7H-pyrazolo[5,1-c]-1,2,4-triazole azomethine dyes.

Analysis of triplet energy transfer rate constants gives the triplet energies of six 7H-pyrazolo[5,1-c]-1,2,4-triazole azomethine dyes, with lambda max values in the range 546-633 nm in ethanol, to lie in the range 115-88 kJ mol-1. Energy transfer rates from porphyrin and phthalocyanine sensitisers can be well approximated using the Balzani equation with a zero or small reorganization energy, and a transmission coefficient ca. 1/1000 that of the fully adiabatic value.