The experimental model of laboratory animals’ intoxication by polyacrylonitrile pyrolysis products

Purpose of research – To develop an experimental model of intoxication of laboratory animals by polyacrylonitrile pyrolysis products. Materials and methods. The study was performed on the rats. Pyrolysis of polyacrylonitrile fibers was carried out at temperature of 270–350 °C. The laboratory animals were exposed to static inhalation intoxication by pyrolysis products for 15 min. Vital signs were determined in animals before and 5 minutes after intoxication. Arterial blood oxygenation index and acid-base state parameters were evaluated at 10 min after exposure. Qualitative detection of cyanides in brain and myocardial samples obtained 15 minutes after intoxication was carried out by gas chromatography. Results and discussion. It was found that the weight of the material (containing 85 % polyacrylonitrile), which pyrolysis products lead to the death of 50 % of laboratory animals within 24 hours after exposure, was 0.81 ± 0.15 g. The animals showed signs of poisoning by substances interrupting the processes of cell bioenergy when exposed to pyrolysis products obtained under specified conditions. The evident bradycardia and bradypnea (p < 0,05), and significant decrease in rectal temperature was marked. The exposed animals did not differ (p > 0,05) from the rats of the control group by the parameters of oxygenation. The signs of decompensated metabolic acidosis were detected in blood. The cyanide peak was detected by gas chromatography with a retention time of 3.78 min in brain and heart muscle biopsies. The experimental model, in which inhalation exposure of pyrolysis products of polyacrylonitrile fibers led to severe intoxication of laboratory animals, was developed. The model can be used to search for means of etiotropic and pathogenetic therapy of poisoning by combustion products of nitrogen-containing polymeric materials

A Practical, Accurate, Information Criterion for Nth Order Markov Processes

The recent increase in the breath of computational methodologies has been matched with a corresponding increase in the difficulty of comparing the relative explanatory power of models from different methodological lineages. In order to help address this problem a Markovian information criterion (MIC) is developed that is analogous to the Akaike information criterion (AIC) in its theoretical derivation and yet can be applied to any model able to generate simulated or predicted data, regardless of its methodology. Both the AIC and proposed MIC rely on the Kullback–Leibler (KL) distance between model predictions and real data as a measure of prediction accuracy. Instead of using the maximum likelihood approach like the AIC, the proposed MIC relies instead on the literal interpretation of the KL distance as the inefficiency of compressing real data using modelled probabilities, and therefore uses the output of a universal compression algorithm to obtain an estimate of the KL distance. Several Monte Carlo tests are carried out in order to (a) confirm the performance of the algorithm and (b) evaluate the ability of the MIC to identify the true data-generating process from a set of alternative models

Evaluating the discriminatory power of EQ-5D, HUI2 and HUI3 in a US general population survey using Shannon’s indices

OBJECTIVES: To compare quantitatively the discriminatory power of the EQ-5D, HUI2 and HUI3 in terms of absolute and relative informativity, using Shannon's indices. METHODS: EQ-5D and HUI2/3 data completed by a sample of the general adult US population (N = 3,691) were used. Five dimensions allowed head-to-head comparison of informativity: Mobility/Ambulation; Anxiety/Depression/Emotion; Pain/Discomfort (EQ-5D; HUI2; HUI3); Self-Care (EQ-5D; HUI2); and Cognition (HUI2; HUI3). Shannon's index and Shannon's Evenness index were used to assess absolute and relative informativity, both by dimension and by instrument as a whole. RESULTS: Absolute informativity was highest for HUI3, with the largest differences in Pain/Discomfort and Cognition. Relative informativity was highest for EQ-5D, with the largest differences in Mobility/Ambulation and Anxiety/Depression/Emotion. Absolute informativity by instrument was consistently highest for HUI3 and lowest for EQ-5D, and relative informativity was highest for EQ-5D and lowest for HUI3. DISCUSSION: Performance in terms of absolute and relative informativity of the common dimensions of the three instruments varies over dimensions. Several dimensions are suboptimal: Pain/Discomfort (EQ-5D) seems too crude with only 3 levels, and the level descriptions of Ambulation (HUI3) and Self-Care (HUI2) could be improved. In absence of a formal measure, Shannon's indices provide useful measures for assessing discriminatory power of utility instrument

Cryptanalysis of Masked Ciphers: A not so Random Idea

A new approach to the security analysis of hardware-oriented masked ciphers against second-order side-channel attacks is developed. By relying on techniques from symmetric-key cryptanalysis, concrete security bounds are obtained in a variant of the probing model that allows the adversary to make only a bounded, but possibly very large, number of measurements. Specifically, it is formally shown how a bounded-query variant of robust probing security can be reduced to the linear cryptanalysis of masked ciphers. As a result, the compositional issues of higher-order threshold implementations can be overcome without relying on fresh randomness. From a practical point of view, the aforementioned approach makes it possible to transfer many of the desirable properties of first-order threshold implementations, such as their low randomness usage, to the second-order setting. For example, a straightforward application to the block cipher LED results in a masking using less than 700 random bits including the initial sharing. In addition, the cryptanalytic approach introduced in this paper provides additional insight into the design of masked ciphers and allows for a quantifiable trade-off between security and performance