Ian Mitchell Harmatz

Cigarette smoking is associated with higher-risk prostate cancer at the time of diagnosis and increased overall and prostate cancer‒specific mortality. Previous studies indicate smokers are less likely to undergo PSA screening. Herein we investigate the association between smoking and PSA screening using a nationally representative US survey. We hypothesize that smokers are less likely to undergo guideline-concordant PSA screening. We performed a cross-sectional analysis of men aged 55 to 69 who responded to the cigarette smoking and PSA screening questions of the 2018 Behavioral Risk Factor Surveillance System survey. Adjusted prevalence and adjusted risk differences were calculated using complex weighted multivariable Poisson regression modeling. We identified 58,996 individuals who qualified for analysis. PSA screening prevalence was 39% (95% CI: 39%-40%) nationally, 42% (95% CI: 41%-44%) for never smokers, 42% (95% CI: 39%-40%) for former smokers, and 27% (95% CI: 25%-29%) for current smokers, including 27% (95% CI: 24%-29%) for daily smokers and 29% (95% CI: 24%-33%) for nondaily smokers. Compared to never smokers, the adjusted relative risk for undergoing PSA screening was 0.81 for current smokers (95% CI: 0.75-0.88, P < .01) and 0.99 for former smokers (95% CI: 0.94-1.03, P = .53). Current smokers are less likely to undergo recommended PSA screening, but former smokers are screened at similar rates as never smokers. As delays in diagnosis may substantially contribute to worse prostate cancer outcomes, targeted interventions to increase screening in this population may yield significant effects.

Locomoting microscale robots--microswimmers--have the potential to impact numerous applications due to their ability to selectively interact with their environment with microscale control. Previous microswimmer designs lack either submicron-level precision over their construction or instantaneous control over their shape. Thus, existing microswimmer designs limit the control afforded over microswimmer interactions with their environment. This work presents a magnetically actuated microswimmer constructed from DNA and microspheres in a hybrid top-down and bottom-up assembly technique that allows for submicron-level precision over microswimmer body construction. Microscale features were fabricated via two-photon polymerization, from which polydimethylsiloxane templates were molded. Templated assembly by selective removal was used to deposit microspheres of select size and composition into the templates. This technique was confirmed to be size-selective within a population of microspheres. To construct the microswimmer, a ferromagnetic microsphere and a nonmagnetic microsphere were deposited into a template, connected with DNA nanotubes in their arrangement, magnetized, and pulled from the template. We demonstrate instantaneous control over shape changes via expansion and contraction of a microswimmer's body in an external magnetic field. In a rotating magnetic field of constant magnitude, the microswimmer expanded as the two microspheres separated a distance of 4.1±0.5 micrometers, approximately the distance between microspheres deposited in the template. In an oscillating magnetic field, the same microswimmer contracted and locomoted 58.8±0.7 micrometers over 126 seconds. [2020-0183]