Virgin PP was blended with the synthesized prodegradants (0.2%) and blown into films. To study the photodegradation behavior of PP with and without the prodegradants under natural weathering conditions, all of the films were exposed to sunlight according Fosbretabulin to the procedure of ASTM 1435. All of the weathered films were found to degrade after a certain number of days of exposure; this was found from the steep increases in the carbonyl, hydroperoxide, hydroxyl, lactone, ester, carboxylic acid, and crystallinity indices. At the same time, a sudden decrease in the elongation at break percentages and tensile strength and surface cracks were also
observed. PP containing the prodegradants degraded this website at a faster rate than the virgin material. The time taken for the material to lose half of the elongation at break value was taken as the half-time, and this was used to determine the effectiveness of the prodegradants. The effectiveness of
the prodegradants for the photodegradation of PP was found to be in the following order: MF03 > MF04 > MF05 > MF06 > MF07. With increasing alkyl chain length of the prodegradants, the stability of the alkyl radical increased, whereas the mobility of the radical in the PP matrix decreased. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 2601-2612, 2010″
“Aims: To assess the effectiveness of different on-treatment correction strategies on set-up accuracy in patients with head and neck cancer (HNC) treated on a TomoTherapy HiArt (TM) system. To assess the adequacy of clinical target
volume (CTV) to planning target volume (PTV) treatment planning margins when treating with intensity-modulated radiotherapy without daily image guidance.
Materials and methods: The set-up accuracy measured by daily online volumetric imaging was retrospectively reviewed for the first 15 patients with HNC treated on the TomoTherapy unit at Addenbrooke’s Hospital. For each fraction, megavoltage computed tomography was carried out, any discrepancy from the planning scan was BMS-777607 concentration noted, and corrected, before treatment. These data were used to evaluate imaging correction protocols using three different action levels. The first three fractions were imaged and used to correct for systematic error, using a 5 mm action level (5 mmAL), a 3 mm action level (3 mmAL), and no action level (NAL). All imaging strategies were applied, to assess the number of fractions that would potentially have exceeded a 5 and 3 mm margin. Systematic and random errors were calculated for the population, assuming the NAL protocol had been applied, and minimum CTV-PTV margins, required to allow for errors attributable only to set-up, were calculated using van Herk’s formula.
Results: In total, 490 fractions were analysed.