Universidad Simón Bolívar

Monte Carlo techniques were used to simulate the air diffusion of exhaled radon/thoron atoms from a wall, the formation and decay of different radioactive species during transport, and the response of a bare LR-115 detector placed on the exhaling surface. The spatial distributions of radionuclide decays and the detector's partial sensitivities to radon/thoron and their progeny were determined. The simulation results were numerically validated through comparisons with published theoretical and experimental data. From the simulated experiments, the contributions of different species to the total track density and what the detector might measure in the studied configuration and assumed parameters were inferred. It was shown that near the wall, where the effective volumes of all species are located, the number of radon atoms was approximately constant, while that of thoron decreased to about 30% relative to the number of exhaled atoms, and the equilibrium factors of both gases were very low. A negligible contribution of ²²⁰Rn and ²¹⁶Po to the track density is expected if the distance between detector's edges and support exceeds 5-6 times the thoron characteristic diffusion length. For similar detector and support sizes, these atoms can significantly contribute to the track density if thoron exhalation rate from wall is high. The advantages and limitations of the detector exposure method for estimating indoor radon concentrations are analyzed. Finally, a simple method is suggested for more accurate radon measurements using the bare LR-115 detector placed on a wall.

The unwanted low-level doping present in supposedly undoped MOSFET channels has a significant effect on charge control and Lambert W function-based inversion charge MOSFET models, as well as on subsequent drain current models.We show that the hypothetical intrinsic MOSFET channel approximation, often used to describe a nominally undoped channel, produces significant errors, even for the low-level concentrations resulting from unintentional doping.We show that the traditional charge control model, which math. describes the gate voltage as the sum of one linear and one logarithmic term of the inversion charge, is only valid for the hypothetically intrinsic case.However, it may still be used for nominally undoped but unintentionally low-doped channel devices within the region of operation where the majority carriers are the dominant charge.With this in mind, we present here a better approximation of the nominally undoped MOSFET channel surface potential.We also propose an improved modified expression that describes the gate voltage as the sum of one linear and two logarithmic terms of the inversion charge.A new approx. drain current control formulation is also proposed to account for parasitic series resistance and/or mobility degradationThe new model agrees reasonably well with measurement data from nominally undoped vertically stacked GAA Si Nano Sheet MOSFETs.

There is limited real-world evidence that evaluates the impact of monotherapy vs. combination therapy as a maintenance treatment in comorbid post-traumatic stress disorder (PTSD) in bipolar disorder (BD). Our aim was to compare lithium vs. lithium plus quetiapine in maintenance treatment in a sample of comorbid BD with PTSD. An exploratory, comparative pilot study over a 28-week period in 34 comorbid BD with PTSD patients was performed to compare monotherapy (n = 18) vs. combination therapy (n = 16) during maintenance treatment. The primary outcome was the time to event of recurrence of any mood episode. The secondary outcomes were regarding change from the baseline to endpoint in the Montgomery-Asberg Depression Rating Scale (MADRS) and Young Mania Rating Scale (YMRS). A Cox regression, Kaplan-Meir survival, and mixed-effects model for repeated measures analyses were performed. Lithium plus quetiapine reduces the risk of recurrence of any mood episode. There are significant differences between baseline and endpoint for YMRS, MADRS, and CGI-BP scales in the sample. In this pilot, exploratory analysis, combination therapy during maintenance treatment for comorbid BD with PTSD may be effective in preventing recurrences of any type of mood episode.