Optimal experimental design for cytogenetic dose-response calibration curves

Purpose: To introduce optimal experimental design techniques in the cytogenetic biological dosimetry practice. This includes the development of a new optimality criterion for the calibration of radiation doses. Materials and Methods: The most typical optimal design criterion and the one developed in this research are introduced and applied in an example from the litera- ture. In another example from the literature, a simulation study has been performed to compare the standard error of the dose estimation using different experimental designs. An RStudio project and a GitHub project have been developed to repro- duce these results. Results: In the paper it is observed that the application of optimal experimental design techniques can reduce the standard error of biodosimetric dose estimations. Conclusions: Optimal experimental design techniques jointly with practitioners re- quirements may be applied. This practice would not involve an additional laboratory work

An exact goodness-of-fit test based on the occupancy problems to study zero-inflation and zero-deflation in biological dosimetry data

The goal in biological dosimetry is to estimate the dose of radiation that a suspected irradiated individual has received. For that, the analysis of aberrations (most commonly dicentric chromosome aberrations) in scored cells is performed and dose response calibration curves are built. In whole body irradiation (WBI) with X- and gamma-rays, the number of aberrations in samples is properly described by the Poisson distribution, although in partial body irradiation (PBI) the excess of zeros provided by the non-irradiated cells leads, for instance, to the Zero-Inflated Poisson distribution. Different methods are used to analyse the dosimetry data taking into account the distribution of the sample. In order to test the Poisson distribution against the Zero-Inflated Poisson distribution, several asymptotic and exact methods have been proposed which are focused on the dispersion of the data. In this work, we suggest an exact test for the Poisson distribution focused on the zero-inflation of the data developed by Rao and Chakravarti (Some small sample tests of significance for a Poisson distribution. Biometrics 1956;12 : 264–82.), derived from the problems of occupancy. An approximation based on the standard Normal distribution is proposed in those cases where the computation of the exact test can be tedious. A Monte Carlo Simulation study was performed in order to estimate empirical confidence levels and powers of the exact test and other tests proposed in the literature. Different examples of applications based on in vitro data and also data recorded in several radiation accidents are presented and discussed. A Shiny application which computes the exact test and other interesting goodness-of-fit tests for the Poisson distribution is presented in order to provide them to all interested researchers

Optimal experimental design for cytogenetic dose-response calibration curves

Purpose: To introduce optimal experimental design techniques in the cytogenetic biological dosimetry practice. This includes the development of a new optimatility criterion for the calibration of radiation doses. Materials and Methods: The most typical optimal design criterion and the one developed in this research are introduced and applied in an example from the litera- ture. In another example from the literature, a simulation study has been performed to compare the standard error of the dose estimation using di erent experimental designs. An RStudio project and a GitHub project have been developed to repro- duce these results. Results: It is appreciated how the application of optimal experimental design tech- niques can reduce the standard error of biodosimetric dose estimations. Conclusions: Optimal experimental design techniques jointly with practitioners re- quirements may be applied. This practice would not involve an additional laboratory work

Monotonicity conditions for multirate and partitioned explicit Runge-Kutta schemes

Multirate schemes for conservation laws or convection-dominated problems seem to come in two ¿avors: schemes that are locally inconsistent, and schemes that lack mass-conservation. In this paper these two defects are discussed for one-dimensional conservation laws. Particular attention will be given to monotonicity properties of the multirate schemes, such as maximum principles and the total variation diminishing (TVD) property. The study of these properties will be done within the framework of partitioned Runge-Kutta methods. It will also be seen that the incompatibility of consistency and mass-conservation holds for ‘genuine’ multirate schemes, but not for general partitioned methods

Prezioso come uno scarto: dal permeato di siero un imballaggio sostenibile ad attività antimicrobica

L\u2019interesse verso gli imballaggi alimentari attivi sta rapidamente crescendo. In quest\u2019ottica, il progetto NANOSAK ha consentito di sviluppare a partire da permeato da ultrafiltrazione di siero materiali attivi in grado di inibire lo sviluppo di Listeria monocytogenes

Scutoids are a geometrical solution to three-dimensional packing of epithelia

As animals develop, tissue bending contributes to shape the organs into complex three-dimensional structures. However, the architecture and packing of curved epithelia remains largely unknown. Here we show by means of mathematical modelling that cells in bent epithelia can undergo intercalations along the apico-basal axis. This phenomenon forces cells to have different neighbours in their basal and apical surfaces. As a consequence, epithelial cells adopt a novel shape that we term “scutoid”. The detailed analysis of diverse tissues confirms that generation of apico-basal intercalations between cells is a common feature during morphogenesis. Using biophysical arguments, we propose that scutoids make possible the minimization of the tissue energy and stabilize three-dimensional packing. Hence, we conclude that scutoids are one of nature's solutions to achieve epithelial bending. Our findings pave the way to understand the three-dimensional organization of epithelial organs

Uncertainty on radiation doses estimated by biological and retrospective physical methods

Biological and physical retrospective dosimetry are recognised as key techniques to provide individual estimates of dose following unplanned exposures to ionising radiation. Whilst there has been a relatively large amount of recent development in the biological and physical procedures, development of statistical analysis techniques has failed to keep pace. The aim of this paper is to review the current state of the art in uncertainty analysis techniques across the ‘EURADOS Working Group 10— Retrospective dosimetry’ members, to give concrete examples of implementation of the techniques recommended in the international standards, and to further promote the use of Monte Carlo techniques to support characterisation of uncertainties. It is concluded that sufficient techniques are available and in use by most laboratories for acute, whole body exposures to highly penetrating radiation, but further work will be required to ensure that statistical analysis is always wholly sufficient for the more complex exposure scenarios

Males and females with first episode psychosis present distinct profiles of social cognition and metacognition

Altres ajuts: Royal Society of New Zealand - Marsden (E2987-3648) ; Obra Social La Caixa (RecerCaixa call 2013) ; Obra Social Sant Joan de Déu BML (RTI2018-100927-J-I00) ; Ministerio Regional de Salud AndaluzDeficits in social cognition and metacognition impact the course of psychosis. Sex diferences in social cognition and metacognition could explain heterogeneity in psychosis. 174 (58 females) patients with frst-episode psychosis completed a clinical, neuropsychological, social cognitive, and metacognitive assessment. Subsequent latent profle analysis split by sex yielded two clusters common to both sexes (a Homogeneous group, 53% and 79.3%, and an Indecisive group, 18.3% and 8.6% of males and females, respectively), a specifc male profle characterized by presenting jumping to conclusions (28.7%) and a specifc female profle characterized by cognitive biases (12.1%). Males and females in the homogeneous profle seem to have a more benign course of illness. Males with jumping to conclusions had more clinical symptoms and more neuropsychological defcits. Females with cognitive biases were younger and had lower self-esteem. These results suggest that males and females may beneft from specifc targeted treatment and highlights the need to consider sex when planning interventions