Verification of TG-61 dose for synchrotron-produced monochromatic x-ray beams using fluence-normalized MCNP5 calculations

Ion chamber dosimetry is being used to calibrate dose for cell irradiations designed to investigate photoactivated Auger electron therapy at the Louisiana State University CAMD synchrotron facility. This study performed a dosimetry intercomparison for synchrotron-produced monochromatic x-ray beams at 25 and 35 keV. Ion chamber depth-dose measurements in a PMMA phantom were compared with the product of MCNP5 Monte Carlo calculations of dose per fluence and measured incident fluence. Monochromatic beams of 25 and 35 keV were generated on the tomography beamline at CAMD. A cylindrical, air-equivalent ion chamber was used to measure the ionization created in a 10x10x10-cm3 PMMA phantom for depths from 0.6 to 7.7 cm. The American Association of Physicists in Medicine TG-61 protocol was applied to convert measured ionization into dose. Photon fluence was determined using a NaI detector to make scattering measurements of the beam from a thin polyethylene target at angles 30 degrees to 60 degrees. Differential Compton and Rayleigh scattering cross sections obtained from xraylib, an ANSI C library for x-ray-matter interactions, were applied to derive the incident fluence. MCNP5 simulations of the irradiation geometry provided the dose deposition per photon fluence as a function of depth in the phantom. At 25 keV the fluence-normalized MCNP5 dose overestimated the ion-chamber measured dose by an average of 7.2+/-3.0% to 2.1+/-3.0% for PMMA depths from 0.6 to 7.7 cm, respectively. At 35 keV the fluence-normalized MCNP5 dose underestimated the ion-chamber measured dose by an average of 1.0+/-3.4% to 2.5+/-3.4%, respectively. These results showed that TG-61 ion chamber dosimetry, used to calibrate dose output for cell irradiations, agreed with fluence-normalized MCNP5 calculations to within approximately 7% and 3% at 25 and 35 keV, respectively.Comment: 22 pages, 5 figure

Beauty During a Pandemic: The Impact of COVID-19 on the Cosmetic Industry

The cosmetic industry is a multi-billion-dollar industry that has taken a financial hit in 2020 due to COVID-19. The drop in cosmetic usage leaves the industry in question for future consumer intention and behavior. Survey responses from 1,715 female students at a southeastern U.S. public university was obtained using Qualtrics. Results indicate significant differences in cosmetic usage; however, post-COVID predicted usage indicates that cosmetic usage will revert back to pre-COVID levels for eye, lip, and skin cosmetics. For face cosmetics, usage will still be slightly below pre-COVID levels. The most important cosmetic category was skincare, which had the highest levels of usage pre-, mid-, and post-COVID. Price maintained a high priority in pre-, mid-, and post responses. Convenience was not as essential pre-COVID but became extremely important mid-COVID and is shown to continue a high level of importance for post intentions. Managerial implications of these results are discussed

COVID\u27s Positive Implications on Business-to-Business Salesperson Communication and Customer Interaction

This article aims to investigate the impact of the COVID-19 pandemic on industrial salesperson communication with buyers, specifically focusing on the positive outcomes. The authors use a qualitative data collection approach based on grounded theory. Thirteen executives, primarily from the transportation industry, were interviewed. Based on the executive interviews, this study develops the pandemic-induced customer interaction model for the industrial market, drawing from the Technology Acceptance Model (TAM) and innovation diffusion theory. This study is the first to examine the positive impacts of the COVID-19 pandemic on business-to-business sales organization communication. This study contributes to the literature through the creation of the pandemic-induced customer interaction model

Apex : A Point of Departure, Vol.2, No.03 (April 1993)

https://digitalcommons.usm.maine.edu/apex/1014/thumbnail.jp

Apex : A Point of Departure, Vol.4, No.03 (April 1995)

https://digitalcommons.usm.maine.edu/apex/1036/thumbnail.jp

Apex : A Point of Departure, Vol.4, No.06 (July 1995)

https://digitalcommons.usm.maine.edu/apex/1038/thumbnail.jp