The experience of neural network prediction of the need for surgical treatment in patients with the diseases of hepatopancreatoduodenal zone

Aim. Using multilayer perceptron artificial neural network, to develop a mathematical model for predicting the need for surgical intervention in patients admitted for hepatopancreatoduodenal zone diseases and to assess the capabilities for its clinical application. Methods. The study was performed using the data of 488 patients with peptic ulcer, cholecystitis or pancreatitis, analyzed using multilayer perceptron artificial neural network, trained to distinguish vectors of data on risk factors of patients who did or did not require surgical intervention during current hospitalization. Results. Patients in the training sample who had required surgical intervention during hospitalization were different from patients who had undergone conservative treatment by such characteristics as gender, age, duration of the disease, state on admission, and the structure of risk factors. The acquired data made it possible to train the artificial neural network. The ROC analysis of the mathematical model demonstrated the area under the curve (AUC) equal to 0.880 for the training group (n=385) and 0.739 for the clinical approbation group (n=103). Conclusion. The AUC indicators of the created model can be characterized as very good in terms of predicting the need for surgical treatment in the training group and good for the clinical approbation group: sensitivity and specificity of the model exceed 80% in the training group and are highest in patients with peptic ulcer disease; in the clinical approbation group these parameters were lower as expected, however, remained at the level of 60-70%

Current trends in the synthesis of soluble and hot-melt polyimides

The work is devoted to a review of works published in recent years on the development of the chemical structure of soluble and hot-melt copolyimides, including a brief description of their synthesis and properties

Fragmentation channels of relativistic 7^7Be nuclei in peripheral interactions

Nuclei of $^7$Li were accelerated at the JINR Nuclotron. After the charge-exchange reaction involving these nuclei at an external target a second $^7$Be beam of energy 1.23A GeV was formed. This beam was used to expose photo-emulsion chambers. The mean free path for inelastic $^7$Be interactions in emulsion $\lambda$=14.0$\pm$0.8 cm coincides within the errors with those for $^6$Li and $^7$Li nuclei. More than 10% of the $^7$Be events are associated with the peripheral interactions in which the total charge of the relativistic fragments is equal to the charge of the $^7$Be and in which charged mesons are not produced. An unusual ratio of the isotopes is revealed in the composition of the doubly charged $^7$Be fragments: the number of $^3$He fragments is twice as large as that of $^4$He fragments. In 50% of peripheral interactions, a $^7$Be nucleus decays to two doubly charged fragments. The present paper gives the channels of the $^7$Be fragmentation to charged fragments. In 50% of events, the $^7$Be fragmentation proceeds only to charged fragments involving no emission of neutrons. Of them, the $^3$He+$^4$He channel dominates, the $^4$He+d+p and $^6$Li+pchannels constitute 10% each. Two events involving no emission of neutrons are registered in the 3-body $^3$He+t+p and $^3$He+d+d channels. The mean free path for the coherent dissociation of relativistic $^7$Be nuclei to $^3$He+$^4$He is 7$\pm$1 m. The particular features of the relativistic $^7$Be fragmentation in such peripheral interactions are explained by the $^3$He+$^4$He 2-cluster structure of the $^7$Be nucleus.Comment: 10 pages, 3 figures, 3 tables, conference: Conference on Physics of Fundamental Interactions, Moscow, Russia, 5-9 Dec 200