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“Vanadium dioxide (VO2) thin films wer

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“Vanadium dioxide (VO2) thin films were grown on silicon microcantilevers Selleckchem AZD8186 and companion test substrates by pulsed laser deposition followed by in situ annealing in an oxidizing atmosphere, with annealing times used to control crystallite sizes. Annealing times of 18 min produced VO2 films with average crystallite sizes of similar to 10 nm or less, while those annealed for 35 min had crystallites of average size similar to 90 nm, comparable to sample thickness. X-ray diffraction and x-ray photoelectron spectroscopy studies of the samples showed that films with crystallite sizes similar to 40 nm or greater consisted

of substoichiometric VO2 in its monoclinic phase, with preferential orientation with (011) planes parallel to the sample surface, while finer structured samples had a substantially similar composition, but showed no clear evidence of preferential orientation and were probably partially amorphous. Forced vibration experiments were performed with the cantilevers as they were thermally cycled through the VO2 insulator-to-metal transition (IMT). Very large reversible changes in the resonant frequencies of up to 5% (3.6 kHz) as well as hysteretic behavior were observed, which depend strongly on film crystallite size. The average value of Young’s modulus for VO2 films with crystallite sizes of selleck chemical similar to 90 nm was estimated

from the mechanical resonance data at room temperature to be similar to 120 GPa, but the large tensile stresses which develop between film and substrate through the IMT impede a similar determination for the VO2 tetragonal

phase, since the commonly learn more used relationships for cantilever frequencies derived from elasticity theory are not applicable for strongly curved composite beams. The results presented show that VO2 thin films can be useful in novel microscale and nanoscale electromechanical resonators in which effective stiffness can be tuned thermally or optically. This response can provide additional functionality to VO2-based devices which take advantage of other property changes through the IMT. (C) 2010 American Institute of Physics. [doi:10.1063/1.3309749]“
“Feline injection site sarcoma (ISS) is a highly invasive soft tissue tumor that is commonly treated with radiation. Cellular deoxyribonucleic acid (DNA) is the principal target for the biologic effects of radiation with cell killing correlating to the number of double stranded DNA breaks (DSBs). The objective of this study was to determine if radiation-induced damage to feline ISS cells could be detected using a commercially available DNA DSB detection kit. Feline ISS cells were irradiated and evaluated for extent of DSB induction with a gamma-H2AX chemiluminescent kit; results were validated by Western Blot analysis. Irradiated cells showed a significant increase in double strand break induction compared to control cells, which was supported by Western Blot.

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