Uzhhorod National University

About: Uzhhorod National University is a education organization based out in Uzhhorod, Ukraine. It is known for research contribution in the topics: Raman spectroscopy & Laser. The organization has 1089 authors who have published 1056 publications receiving 5187 citations. The organization is also known as: State Higher Education Establishment "Uzhhorod National University" & Uzhhorod State University.

Influence of Pretreatment Root Development Stage on success of Apexification: Forensic Dental Evaluation

Abstract: Clinicians have previously reported effective outcomes of apexification in cases of complicated caries or trauma; however, there is still not enough evidence of how root development stage before treatment influences the success of this procedure. Objectives: The study was performed to evaluate the influence of pretreatment root development stage on the success of apexification, with the use of a modified forensic technique for estimating odontologic age. Methods: Apexification of maxillary and mandibular permanent incisors, first molars, and premolars was provided to 43 pediatric patients with symptoms of irreversible pulp changes or signs of chronic apical periodontitis. Success of apexification was evaluated with the use of a modification of Demirjian et al.’s age estimation technique; root development stages were documented radiologically before and 12 months after treatment. Results: There was a close covariance between pretreatment tooth development stages F and G and the possibility of achieving stage H after apexification (rs = 0.87 and 0.91, respectively; p < 0.05) with an average follow-up period of 11.6 ± 0.7 months. Conclusion: Pretreatment tooth development at stages F to H, as originally proposed by Demirjian et al., was found to significantly influence the prognosis for achieving successful apexification outcome.

Absolute cross sections for the electron-impact formation of cytosine anions

Abstract: The process of negative ion formation by electron impact on cytosine (a nitrous base of nucleic acids) has been studied in crossed molecular and electron beams for electron energies in the interval from 0.4 to 5.0 eV. Using a specially developed method, the molecular beam intensity was determined and the energy dependence of the absolute cross section Q for the formation of cytosine anions was studied. The maximum ionization cross section σ = 4.2 × 10−18 cm2 was observed for an electron energy of 1.5 eV.

Optimizing nonlinear beam coupling in low-symmetry crystals.

Abstract: The purpose of this paper is to find the polarizations and spatial orientations of the two interacting counterpropagating coherent light waves which ensure the largest beam coupling in monoclinic photorefractive crystal. The results of calculations are presented that are verified experimentally with Sn2P2S6.

The Issue of Efficient Generation of Generalized Features in Algorithmic Classification Tree Methods

Abstract: The paper studies the basic issue of methods of constructing models of algorithmic classification trees which is the problem of generating generalized features in their structure. There has been suggested a simple and efficient method of approximating the initial training dataset with the help of a set of generalized features of the type of geometric objects in feature space of the current application problem. This approach allows ensuring the necessary accuracy of classification trees, reducing the structural (constructional) complexity and achieving the appropriate performance indicators of the model. Based on the proposed algorithmic scheme of the training set coverage there has been developed the corresponding software which enables the work with a set of different-type applied problems of data processing. Hence, a simple, efficient and economical approximation of the initial training set provides the appropriate speed, level of complexity of the classification scheme, which ensures the simple and complete recognition (coverage) of sets of discrete objects.

The use of photodynamic therapy in the treatment of dental caries in children of contaminated areas of the ecosystem of the upper tysa region.

Abstract: Objective The aim: improving the effectiveness of treatment of dental caries in children using the method of photodynamic therapy. Patients and methods Materials and methods: The treatment of permanent tooth decay was performed in 35 children of the Upper Tysa region aged 12-15 years. Using the polymerase chain reaction method, the clinical efficacy of photodynamic therapy in the treatment of dentin caries was determined. Results Results: During the study, by PCR analysis, dentin caries most commonly revealed genetic markers of DNA of the five most virulent anaerobic bacteria: Prevotella intermedia, Fusobacterium spp., Enterococcus Faecalis, Veilonella spp., Candida albicans. After treatment of the carious cavity by the method of photodynamic therapy with exposure of 30 s - fusobacterium spp. were not detected, the detection rate of prevotella intermedia decreased 3-fold, enterococcus faecalis 3.5-fold, veilonella spp.- 5-fold, and candida albicans- 8-fold; after treatment with carious cavities with 60 s exposure - anaerobic microorganisms were not detected in the investigated samples. The effect of photodynamic therapy with laser exposure of 60 seconds on caries-causing streptococci resulted in their total death, and with exposure of 30 seconds - the frequency of isolated strains decreased several folds. Conclusion Conclusions: The use of photodynamic therapy in the treatment of dentine caries is a highly effective and pathogenetically sound method of treatment that provides a significant reduction in the optional and obligate types of cariesogenic microorganisms.