This is based on the analysis of several substances from the vitreous humour of the eye of cadavers, according to an article published in the journal entitled Statistics in Medicine. Using this system, scientists have developed a piece of software that makes it possible to establish precisely the post mortem interval (PMI), information that will make the work of the police and the courts of justice easier.
To apply this technique the researchers analyse initially potassium, urea and hypoxantine (a DNA metabolite) concentrations present in the vitreous humour of the eye of the human cadaver, and introduce these figures into a computer programme. The software that has been invented by these Galician scientists uses this information and is capable of establishing the time at which death occurred.
“The equations we have developed now make it possible for us to estimate the PMI more precisely than before, and provide a useful and accessible tool to forensic pathologists that is easy to use” José Ignacio Munoz Barús, one of the authors of the study, explains to SINC, and who is also a specialist doctor from the Institute of Legal Medicine at the University of Santiago de Compostela.
The traditional techniques for estimating the PMI are based on the study of parameters such as the rectal temperature of the cadaver or one of the organs, such as the liver, in rigor mortis, or post mortem lividity examination. These methods are complemented by biochemical analyses of the body fluids. One of these is the vitreous humour, the gelatinous liquid that is found behind the crystalline lens of the eye.Muñoz Barús points out that the study, published recently in Statistics in
In this last case the researcher specifies that previous studies used a “linear regression mathematical model” which assumes that the concentrations of potassium, hypoxantine and urea increase in a linear way that is more or less constant throughout the post mortem interval. However, the new analyses suggest that those premises are not valid and that the statistical models known as generalized additive models (GAM) or the support vector machine (SVM) models are more flexible and much more useful, since they avoid the assumption of linearity”.
The precision and usefulness of these two models have been confirmed by chemical analysis in more than 200 vitreous humour samples. The doctor and the two mathematicians who have performed the study have verified that the SVM method offers more precise data, although the GAM method is more easy to assimilate to the linear model and understand graphically and numerically, “ for which reason both complement each other”.
The three scientists have incorporated all this information into the development of a free computer package (based on code “R”) which makes it possible to establish the PMI using four predictive variables: concentrations of potassium, hypoxantine and urea, and cause of death. In addition, the software makes it possible to show the results graphically. “In this way the estimation of the time of death and expert examination are made easier when attending the courts of justice”, Munoz Barús points out to SINC
“The precise determination of the exact time of death has been the subject of various studies going back to the 19th century, since this information is of paramount importance in the field of legal medicine, owing to its repercussions on crime and civil society. This new method offers an important contribution to this field”, the researcher concludes.
SINC Team | alfa
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
The Nagoya Protocol Creates Disadvantages for Many Countries when Applied to Microorganisms
05.12.2016 | Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Power and Electrical Engineering
05.12.2016 | Materials Sciences
05.12.2016 | Power and Electrical Engineering