The destruction of rock under the condition of a close submerged jet has become a hot topic of scientific research and engineering application in the past decade. With the unremitting efforts of a large number of experts and scholars around the world, gratifying progress has been made in the research of computational fluid dynamics (CFD) on the internal and external flow fields of the jet nozzle, the theoretical derivation of rock mechanics on the fracture initiation and propagation criteria of hydraulic fracturing, and the numerical simulation of jet erosion mechanism under the coupling of fluid and solid fields, however, for the rock mechanics hydraulic fracturing cutting engineering scale of non-oil drilling fracturing technology, the research on the fluid-solid coupling boundary conditions of fracturing fluid and hard dense rock under the flow state conditions of the submerged field inside and outside the borehole is not sufficient. In the calculation of the fluid-solid coupling boundary flow field under the non-submerged jet state, the control equation with Reynolds number between 2300-4000 shall be selected, while it belongs to the laminar flow state in the stage of hole sealing and pressurised fracturing. Therefore, Von-Mises equivalent plastic stress is selected in the mechanical model to calibrate the failure state of the rock-solid boundary, and the control equations of laminar flow and turbulent flow are selected to calibrate the fluid boundary. The mechanism of different stages of rock breaking by hydraulic fracturing jet can be further analysed in detail, and Comsol 6.0 multi-physical field simulation software is selected for verification. The research results will help deepen the understanding of rock breaking mechanism by jet and optimise the selection of parameters for field construction.

The article contains preliminary considerations on the principles of the standardization of geographical names in Poland, in particular the names of physiographic objects. The notion of a country’s language policy has been referred to as one of its tools is the standardization of geographical names. The general objectives of the Polish language policy were listed as such: the assertion of legal status of the Polish language as the first language in Poland; the assertion of conditions for the development of national and ethnic minority languages in the country; the construction of a Polish- language national and state community. Legal acts concerning Polish language and geographical nomenclature were indicated. It was stated that the assumed effect of political and linguistic actions should be to develop a nomenclature in correct Polish, one which is pragmatically effective, rooted in tradition and, as a result of this study, one should expect to achieve an optimal course of the language communication process in each communicative community. Then, the criteria of the linguistic correctness of geographical names applied to date were discussed and similarities indicated in the standardization procedure with regards to geonyms and specialist terms. The rules of the detailed standardization procedure will be presented in the second part of the article

According to the Polish Ministry of Science and Higher Education and Polish Central Statistical Office the number of students systematically decreases since 2015. This demographic change was a reason to examine students motivation for undertaking their studies in order to improve educational program and to encourage students to peruse higher education. By approaching the subject of “Motivations for Undertaking Special Education Studies in The Opinion of Students at Pedagogical University of Cracow”, the answers were sought to the three following questions: What were the main reasons for choosing studies at Pedagogical University of Cracow? What motivators played a key role for students while selecting field of studies? What student’s personality traits did mainly influence their choice? Research material was collected basing on a self-designed questionnaire. The group of first-year 54 students year were tested, in which 39% didn’t know which specialization they would choose after a one year. The article’s conclusions present key factors motivating students for undertaking Special Education Studies and explain how personality traits influenced their choice.

The focus of this study is to investigate the applicability of natural mineral iron disulfide (pyrite) in degradation of aromatic compounds including benzene and several chlorinated benzenes (from mono-chlorinated benzene (CB), di-chlorinated benzenes (di-CBs) to tri-chlorobenzenes (tri-CBs) in aerobic pyrite suspension by using laboratory batch experiments at 25°C and room pressure. At first, chlorobenzene was studied as a model compound for all considered aromatic compounds. CB was degraded in aerobic pyrite suspension, transformed to several organic acids and finally to CO₂ and Cl^-. Transformations of remaining aromatic compounds were pursued by measuring their degradation rates and CO₂ and Cl^- released with time. Transformation kinetics was fitted to the pseudo-first-order reactions to calculate degradation rate constant of each compound. Degradation rates of the aromatic compounds were different depending on their chemical structures, specifically the number and position of chlorine substituents on the benzene ring in this study. Compounds with the highest number of chlorine substituent at m-positions have highest degradation rate (1,3,5-triCB > 1,3-diCB > others). Three chlorine substituents closed together (1,2,3-triCB) generated steric hindrance effects. Therefore 1,2,3-triCB wasthe least degraded compound. The degradation rates of all compounds were in the following order: 1,3,5-triCB > 1,3-diCB > 1,2,4-triCB ≅ 1,2-diCB ≅ CB ≅ benzene > 1,4-diCB > 1,2,3-triCB. The final products of the transformations were CO₂ and Cl^-. Oxygen was the common oxidant for pyrite and aromatic compounds. The presence of aromatic compounds reduced the oxidation rate of pyrite, which reduced the amount of ferrous and sulfate ions release to aqueous solution.

B a c k g r o u n d: The digital rectal examination (DRE) is a part of the standard physical examination and a useful diagnostic tool for detecting various lower gastrointestinal tract abnormalities. However nowadays it has been observed that medical students might not be properly prepared for performing and interpreting of DRE. The purpose of the study was to evaluate the knowledge and experience of Polish medical students about DRE.

Ma t e r i a l a n d M e t h o d s: A prospective study was carried out using a questionnaire accessible via internet platform. The survey consisted of 12 questions and considered experience as well as practical and theoretical knowledge about DRE. 976 responses from nine Polish medical universities were included in the study.

R e s u l t s: 38.68% of students have never performed DRE with “lack of opportunity during courses” (71.09%) as the most common reason. Among responders who performed this examination only 12.72% had done it more than two times. Usefulness of DRE was mostly assessed as high and very high (55.63%). Students in the self-assessment part indicated low and very low (18.72% and 39.61%) technical abilities and also low (25.34%) interpretation skills.

C on c l u s i o n: The knowledge of Polish medical students about DRE is insuffi cient. Medical universities should pay particular attention to this fi eld of examination to improve theoretical as well as practical skills of future doctors.

Background: Anorexia nervosa is a widely prevalent eating disorder that often leads to life-threatening complications. Since it mostly concerns females, many authors have focused on studying the reproductive system in anorexic women. Recently discovered telocytes may give a new insight into the pathophysiology of gynecological complications in these patients.

Material and Methods: We adopted an animal model of anorexia nervosa induced by voluntary physical activity. Sixteen female Wistar rats were divided into two groups: control and activity-based anorexia. When the weight loss of activity-based anorexia (ABA) rats reached 25% animals were euthanized. Size and weight measurements as well as histopathological analysis of the reproductive organs were performed. Additionally, we used immunohistochemical staining for detection of telocytes.

Results: Telocytes were identified in uteri of anorectic rats but no diff erences were observed when compared to the control group. Nevertheless, in the ABA group the weight of the uteri and the number of follicles in the ovaries decreased significantly.

Conclusions: Our rat model of anorexia nervosa mimics the effects of this eating disorder that occur in the female reproductive system since we reported ovarian dysfunction and uterine involution in the experimental animals. It supports its potential role in the further studies of anorexia pathophysiology and treatment possibilities.