Danielle Royston

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DNA damage from photon scatter or beam spread during UV excimer laser irradiation was investigated using the induction of bacteriophage lambda in E. coli BR339. Prophage induction in these cells leads to the production of beta-galactosidase which can be detected colorimetrically by the application of appropriate substrates. An agar surface overlayed with(More)
Heart failure (HF) patients appear to exhibit impaired thermoregulatory capacity during passive heating, as evidenced by diminished vascular conductance. Although some preliminary studies have described the thermoregulatory response to passive heating in HF, responses during exercise in the heat remain to be described. Therefore, the aim of this study was(More)
The optical emission pattern of experimental sphere-tipped fibers and an assortment of shapes of sapphire-tipped fibers has been measured. The emission patterns were recorded in both air and water. These patterns show that cone and wedge shaped tips unexpectedly have focusing properties. The observed patterns help give an understanding of the results that(More)
Round sapphire and silica tips have been studied as surgical probes for focusing Nd:YAG laser radiation during various surgical indications. Since most of these data have been obtained with silica tips from Surgical Laser Technology, there are limited data on the physical performance of round sapphire tips. An investigation of round sapphire tip performance(More)
This study evaluated the performance of sapphire and fused silica hemispherical tips under the same exposure conditions. Lesions produced in the chicken breast and a blood field were sectioned for light and transmission polarizing microscopy. Lesion size and thermal damage area were recorded as a function of the tips accumulated exposure. The tips(More)
Side-firing fibers are used to provide coagulative therapy to the urologic tract. These fibers use different optical technologies to deflect the beam transverse to the fibers' optical axis. This produces emitted beams which differ in both beam direction and divergence angles. The relative optical performance of 13 fibers was studied in an optical phantom(More)
Both CO2 and argon laser ablation of an agar substrate containing high titres of bacteriophage phi X174 create plumes which disperse viable phage particles. Irradiances at the beam impact site ranged from 73 to 215 W/cm2 for the CO2 laser and from 40 to 227 W/cm2 for the argon laser. To increase the absorption of argon laser radiation, oxidized hemoglobin(More)
BACKGROUND AND OBJECTIVE Sapphire and sculpted silica fiber scalpels were evaluated for performance as they aged. Performance was determined by measuring their useful lifetime, forward transmission, incision depth, and the thermal coagulation thickness at the sides and bottom of the incision. STUDY DESIGN/MATERIALS, AND METHODS: Aging was performed with a(More)