Monradmccallum0125

The unattached fraction of 220Rn progeny is one of the key parameters in lung dose evaluation models. To study the behavior of unattached 220Rn progeny and to prepare for calibration of the unattached 220Rn progeny monitors, a 220Rn progeny chamber that could stably regulate different unattached fractions of 220Rn progeny was established. A recirculation loop to eliminate the effects of the sampling and a loop connected to the dilution chamber to supplement the carrier aerosol were set up. Also, a theoretical model regarding the regulation of the unattached fraction of 220Rn progeny was established. Continuous measurements of the unattached fraction were conducted using the combination of a single-layer wire screen and a filter membrane. The experimental results showed that, under different aerosol levels, the relative standard deviation (RSD) of 212Pb concentration during the continuous samplings was within 10.7% and the RSD of the unattached fraction of 212Pb was within 9.9%. learn more The relative deviation between the theoretical and the experimental values of 212Pb concentration was within 16.7% and the model calculation values of the unattached fraction of 212Pb were consistent with measured results.

The aim of this study was to evaluate the performance of a knowledge-based planning (KBP) model for breast cancer trained on plans performed on a conventional linac with 6 MV FF (flattening filter) beams and volumetric-modulated arc therapy (VMAT) for plans performed on the new jawless Halcyon© system with 6 MV FFF (flattening filter-free) beams.

Based on the RapidPlan© (RP) KBP optimization engine, a DVH Estimation Model was first trained using 56 VMAT left-sided breast cancer treatment plans performed on a conventional linac, and validated on another 20 similar cases (without manual intervention). To determine the capacity of the model for Halcyon©, an additional cohort of 20 left-sided breast cancer plans was generated with RP and analyzed for both TrueBeam© and Halcyon© machines. Plan qualities between manual vs RP (followed by manual intervention) Halcyon© plans set were compared qualitatively by blinded review by radiation oncologists for 10 new independent plans.

Halcyon© plans generated with the VMAT model trained with conventional linac plans showed comparable target dose distribution compared to TrueBeam© plans. Organ sparingwas comparable between the 2 devices with a slight decrease in heart dose for Halcyon© plans. Nine out of ten automatically generated Halcyon© plans were preferentially chosen by the radiation oncologists over the manually generated Halcyon© plans.

A VMAT KBP model driven by plans performed on a conventional linac with 6 MV FF beams provides high quality plans performed with 6 MV FFF beams on the new Halcyon© linac.

A VMAT KBP model driven by plans performed on a conventional linac with 6 MV FF beams provides high quality plans performed with 6 MV FFF beams on the new Halcyon© linac.

Fetal exposure to cannabis and tobacco during pregnancy leads to adverse fetal and childhood outcomes. We hypothesized that fetal exposure to cannabis and tobacco have persistent programming effects on hypothalamic pituitary adrenal (HPA) axis functioning in childhood. Therefore, we examined the associations of parental cannabis and tobacco use during pregnancy with childhood hair cortisol and cortisone concentrations at 6 years, as biomarkers of long-term HPA-axis functioning.

In a population-based prospective birth cohort among 2577 mothers and their children, information of parental cannabis and tobacco use was collected by questionnaires, and maternal urine samples were additionally analyzed to detect cannabis metabolite concentrations. Cortisol and cortisone were measured in hair samples at 6 years. Linear regression analysis with adjustment for several confounders was used to test our hypothesis.

As compared to non-exposed children, offspring exposed to cannabis during pregnancy (in combination wi consequences of these associations.

Justice-involved youth use cannabis at higher rates than their same-aged peers increasing likelihood of adverse behavioral health consequences and continued legal involvement. This study examined individual level predictors of early onset use cannabis use (<13 years of age) and cannabis use initiation in the 12 months following first court contact.

Participants were 391 first-time justice-involved youth (56.9 % male; M

= 14.6 years; 32.1 % White, 11.1 % Black, 14.7 % Other/Multi-racial, 42.2 % Latinx) and an involved caregiver (87.2 % female; M

= 41.0 years). Baseline assessments captured individual level factors; cannabis use was assessed every four months post-baseline for 12 months. Primary analyses involved multivariable modified Poisson regressions and survival analysis.

In multivariable models, youth who reported lifetime cannabis use (n = 188, 48.1 %) were older, reported alcohol use and positive cannabis use expectancies. Greater self-control and self-concept were associated with lower litice-involved youth. Research is needed to determine whether brief interventions that aim to modify expectancies about cannabis use reduce rates of cannabis initiation in this underserved population.

To examine pre- to postnatal changes in drinking for women and men and assess the role of education level in these changes.

The transition towards parenthood can contribute to significant shifts in alcohol consumption for women and men. Research has generally focused on pregnancy and short-term changes following childbirth, usually for mothers only. Socio-economic variation in the impact of childbirth and return to drinking postnatally is similarly understudied.

Longitudinal alcohol consumption data for 2470 individuals (1248 female) who were pregnant, or the partner of a pregnant woman, were obtained from a representative, Australian survey for three years prior and following birth. Piecewise regression models, including an education-x-time interaction, assessed changes in drinking quantity and frequency.

Female usual quantity and frequency significantly declined during pregnancy, followed by significant postnatal increases in quantity, approaching pre-pregnancy levels, with similar trends across education levels.