Department history

The history of the Department of Obstetrics (now Veterinary Reproductive Medicine) dates back to the beginning of the last century when the Kyiv Veterinary Institute (now the Faculty of Veterinary Medicine) was established in 1920. Unfortunately, during the Second World War, the archive of documents of the Department of Obstetrics of the pre-war period was lost. Therefore, the almost twenty-year history of the department from its foundation in 1928 until 1947 is based on the materials of the first Head K.I. Turkevych (fig.1), described in the ‘Notes on the history of the establishment of the institute in 1947’. There are no official documents on the establishment of the Department of Midwifery as part of the KVZI (Veterinary and Zootechnical Institute in Kyiv), but in the archival records of that time, made by Professor K. I. Turkevych, there is a reference to the fact that ‘... In 1928, the course of obstetrics was removed from the Department of Surgery and transformed into an independent department. ...’. Thus, the date of foundation of the Department of Obstetrics can be considered 1928. Its first Head was Kostiantyn Ivanovych Turkevych. Since then, he has been teaching the subject. He also served as a part-time Head of the Department of Operative Surgery, and from 1926 to 1930 he headed the Veterinary Faculty.

Fig.1. Professor K. I. Turkevych

The Department in 1928-1937.
During this period, the department was replenished with equipment, tools, and visual aids (tables, models). The department had a small museum of canned wet and dry preparations - more than 100 copies. The obstetric clinic of the Veterinary Faculty was popular not only within the city but also far beyond. The number of patients at the clinic at that time ranged from 1500 to 2000 animals per year. In addition, the teachers used to conduct practical classes for students on suburban farms in Kyiv. Since 1936, the Veterinary Faculty has had a special scientific and advisory bureau to assist production, in which Associate Professor K. I. Turkevych took a particularly active part.
Staff of the Chair. In 1931, the Department of Obstetrics was again merged with the Department of Surgery, and only since 1934 it existed as an independent department. In 1933, the department began to teach the course "Artificial Insemination of Farm Animals".
Postgraduate studies. From 1936 to 1938, M. Z. Nemirovskyi and I. S. Nagornyi completed their postgraduate studies at the Department.
Publications. During this period, the staff of the department published ..... works, including the first in 1936, and in 1937- the second one, corrected and supplemented edition of the monograph ‘Udder Diseases and Struggle with Them’ by K. I. Turkevych.
The Department in 1938-1947.
During the Second World War, the KVI was evacuated first to Kharkiv and then to Sverdlovsk. Based at the Kharkiv Veterinary Institute, 113 students in the fifth year of the KVI graduated. One of the graduates of 1941 was P. S. Derevianko (later - Associate Professor of the Department of Obstetrics (1962-1982). I. S. Nagorny (later - Professor and Head of the Department) was mobilized to the front from the Sverdlovsk Agricultural Institute. During the evacuation of Kyiv University (from September 1941 to April 1944), the Department of Obstetrics was headed by Professor P. I. Shatalov. During this time, the department participated in the training of 163 veterinarians. Professor K. I. Turkevych stayed in the occupied territory for health reasons during the occupation. From 1942 he worked in the clinics of the KVI. The annual number of patients in the obstetric clinic during this period ranged from 600-800 animals per academic year.
Staff of the Chair. In the postwar years, the organization of the educational process, its material and technical support, restoration, and equipment of classrooms, clinics, etc., were provided by the Head of the Department, Associate Professor K.I. Turkevych, assistants A.M. Bahlii (acting assistant of the Department since 1946), H.K. Korchak (assistant of the Department since 1948), and resident O.G. Bernstein (employee of the Department in 1949-1950), senior laboratory assistant K.D. Khosidman (employee of the Department in 1950-1951), laboratory assistant M.A. Chernyshova (employee of the Department in 1936-1950), sanitary assistant G.D. Golyk (employee of the Department in 1936-1950), and others.
Publications. During this period, the staff of the department published ..... works, including two monographs by K. I. Turkevych: ‘How to help animals during labor’ (1945) and “Calving and abortion in cows” (1946). In 1946, K.I. Turkevych was the first to use a tissue preparation from cattle liver BPX, made according to the method of V.P. Filatov, for the treatment of animals with gynaecological diseases.
The Department in 1948 - 1957.
During this period, the staff of the department improved the methodology for the manufacture and use of tissue preparations from animal parenchymal organs and introduced them into production for the treatment and prevention of obstetric and gynaecological pathology in animals. The department conducted research to study the causes of cow infertility and develop new methods of diagnosis and prevention. G.K. Korchak actively worked on the problem of infertility in cattle, studying the ways of transmission, clinical manifestation, diagnosis, treatment and prevention of cattle trichomoniasis in individual, collective and state farms.
Staff of the Chair. In 1951-1952, the department was headed (part-time) by Associate Professor Vasyl Andreevskyi Y.(Yakovych), who was also the Head of the Department of the Agricultural Institute in Bila Tserkva. In September 1952, Ivan Sergiyovych Nagornyi, Associate Professor of the Department of Therapy, was elected to the position of the Head of the Department, and he held this position for 33 years (until 1985). In March 1952, T. K. Tryfonova, Candidate of Veterinary Sciences, was elected to the position of the Department's assistant; later, O. Y. Prymak was elected as the Department's assistant (1956-1960). In 1955-1961, the Department was staffed by Associate Professor, Candidate of Biological Sciences S. O. Ksonzenko, who taught the course ‘Artificial Insemination of Farm Animals’.
Publications. During this period, the staff of the department published ..... works, including...
The Department in 1958 - 1967.
In 1958, only 6 employees worked in the Department (fig.2).

Fig. 2. The Department of Obstetrics and Artificial Insemination of Farm Animals in 1958:
top row (from left to right) - chief veterinarian of the clinic O. Y. Pohribniak, resident B. P. Zhdanov, senior laboratory assistant N. I. Sychova; bottom row (from left to right) - assistant G. K. Korchak, associate professors I. s. Nagorny, S. P. Ksonzenko.

A significant contribution to the improvement of the educational process and research work of the department in the 1960s was made by residents L.G. Prusova (employee of the department in 1951-1955), B.P. Zhdanov (employee of the department in 1955-1957), laboratory assistants K. S. Poluliashchenko (employee of the department in 1951-1955), P. I. Kovalenko (employee of the department in 1955-1956), and medical assistant M. S. Vorozka (employee of the department in 1954-1962). With the arrival of V. D. Ferenets and N. I. Sychova to the department in 1956-1957, the work of the department's auxiliary and service staff improved significantly.

Personnel changes. In May 1962, P.S. Derevianko was transferred to the position of Associate Professor of the Department of Obstetrics and Artificial Insemination. From 1 October 1965 to 1 May 1966, he acted as the Head of the Department.
Postgraduate studies. In 1960, the department began training postgraduate students, whose scientific advisers were Associate Professors K. I. Turkevych, I. S. Nagornyi, and I. G. Zorin. Scientific research was carried out on topical issues: tissue therapy, infertility, and the role of protective mechanisms of female genital organs in normal and pathological conditions.
Thesis defenses. During the period 1961-1970, the department prepared and defended 9 PhD and 1 doctoral thesis: G. K. Korchak (1965), V. P. Polishchuk (1966), G. S. Sharapa (1966) and others.
Publications. During this period, the staff of the department published ..... works, including in 1962 G. K. Korchak published the monograph ‘Early recognition of pregnancy and infertility of cows’, and in 1963 - the monograph ‘Trichomoniasis of cattle’. In the same year, I. S. Nagorny published a monograph ‘Ways to eliminate cow infertility’.
Scientific achievements. In 1959, G. K. Korchak received an author's certificate for the development of a scarifier for taking scrapings from the genitals of females and males for laboratory testing for trichomoniasis. The staff of the department were awarded diplomas and medals at VDNKh of the USSR: Large Silver Medal - Associate Professor I.S. Nagorny (1958), Small Silver Medal - Associate Professor G.K. Korchak (1958, 1962), Bronze Medal - Associate Professor I.S. Nagorny, Assistant G.K. Korchak (1955).
The Department in 1968 - 1977.
In 1970, the department consisted of 7 people (fig.3).

Fig. 3. The Department of Obstetrics and Artificial Insemination of Farm Animals in 1970:
top row (from left to right) - Associate Professor V. P. Polishchuk, senior laboratory assistant N. I. Sychova, resident V. D. Ferenets, dissector M. V. Tseluyko, Associate Professor V. S. Bryl; bottom row (from left to right) - Associate Professor H. K. Korchak, Professor I. S. Nagorny, Associate Professor P. S. Derevianko.

Personnel changes. In 1972, V.S. Bryl was enrolled as an assistant of the department, and in 1975 - S.K. Yukhymchuk.
Thesis defenses. In 1968, I. S. Nagorny defended his doctoral thesis, and V. S. Bryl (1972) and S. K. Yukhymchuk (1975) defended their PhD theses.
Publications. During this period, the staff of the department published ..... works, including Professor I. S. Nagorny, Associate Professors H. K. Korchak, V. P. Polishchuk, and P. S. Derevianko - participated in the preparation and publication of the Ukrainian Agricultural Encyclopedia (1970-1971). In 1974, G. K. Korchak published the 2nd edition of the monograph ‘Trichomoniasis of cattle’.
The Department in 1978 - 1987.
In 1980, the department consisted of 10 people (fig.4).

Fig. 4. The Department of Obstetrics and Artificial Insemination of Farm Animals in 1980:
top row (from left to right) - Associate Professor S. K. Yukhymchuk, Researcher Caro Nunez Hugo del Carmen, Laboratory Assistant N. I. Sychova, Associate Professor V. S. Bryl, senior dissector O. M. Vdovenko; bottom row (from left to right) - Associate Professors G. K. Korchak, P. S.Derevyanko, Professor I. S. Nagorny, Resident V. D. Ferenets, Associate Professor V. P. Polishchuk.

Personnel changes. In November 1981, V. S. Bryl was elected to the position of Associate Professor of the department. Associate Professor P. S. Derevianko retired in 1983. V.Y. Lyubetskyi (1983), V.M. Lakatosh (1983), H.I. Pidopryhora (1984) and V. M. Slepchenko (1987). V. P. Polishchuk completed his doctoral studies and returned to the position of Associate Professor (1983).
Thesis defenses. In the 1970s and 1980s, under the guidance of Professor I. S. Nagorny studied in postgraduate studies and defended their PhD theses 8 foreign citizens: Hosni Ibrahim Youssef (Egypt), Mansour Said Eweis (Egypt) (1975); Robert Lopez Marco (Ecuador) (1979); Mahdi Hassan Mahmoud (Iraq) (1982); Gerekobi Luc (CAR) - (1985); Kruk-Mozgawa Grażyna (Poland) - (1988); Darkwa Kwasi Bovey (Ghana). Also, H. M. Kalynovskyi defended his PhD () and doctoral dissertations (1994).
Postgraduate studies. V. I. Borodynya (1984) and V. M. Lakatosh (1986) were enrolled in the full-time postgraduate studies of the department.
Publications. During this period, the staff of the Department published ..... works.

Fig.5. The Department of Obstetrics and Artificial Insemination of Farm Animals in 1987:
top row (from left to right): assistant V.M. Lakatosh, Associate Professor V.Y. Liubetskyi, assistants G. I. Pidopryhora, V.M. Slepchenko;
bottom row (from left to right) - Associate Professor V. S. Bryl, Senior Laboratory Assistant L. O. Shchyhol, Associate Professor V.P. Polishchuk, professor I.S. Nagorny, Associate Professor S.K. Yukhymchuk.

The Department in 1988 - 1997.
In the late 90s, the department consisted of 10 people. The teaching and support staff during this period included senior laboratory assistants L. O. Shchyhol (employee of the department in 1987-1988), O. P. Zubok (employee of the department in 1989-1991), N. H. Sorokina (employee of the department in 1991-1992), T. H. Serdiuk (employee of the Department in 1995-1999), laboratory assistants S.V. Koptieva (employee of the Department in 1987-1989), O. V. Maistrenko (employee of the Department in 1989-1990), V. V. Kubaievska (employee of the Department in 1991-1992), resident M. V. Postolatii (employee of the Department in 1996-1998).
Personnel changes. In 1989, the department suffered a heavy loss: a well-known scientist, clinician, Doctor of Veterinary Sciences, Professor I. S. Nagorny, who had headed the department for 33 years (1952-1985), died. Under his leadership, 3 doctoral and 22 PhD theses were completed. In May 1989, V. I. Sheremeta, Candidate of Agricultural Sciences, a specialist in embryo transplantation in cows, was invited to the department to organise an educational and research laboratory. In 1996, Associate Professor V. M. Lakatosh was appointed acting Head of the Department. In the same year, Doctor of Biological Sciences, Corresponding Member of the Ukrainian Academy of Agrarian Sciences, Honoured Worker of Science and Technology, Member of the Verkhovna Rada of Ukraine of the II convocation V. Yablonsky was invited to the position of Professor of the Department.
Thesis defenses: V. I. Borodynya (1989), G. I. Pidopryhora (1991), V. M. Lakatosh (1994).
Publications. During this period, the staff of the department published ..... works, including in 1990, Associate Professors V. P. Polishchuk and V. S. Bryl participated in the publication of the ‘Handbook of Veterinary Doctor’. In 1993, S. K. Yukhymchuk - in the publication of the ‘Handbook of Veterinary Paramedic’.
The Department in 1998-2007.
In 1998, the department consisted of 10 people (Fig.6).

Fig. 6. The Department of Obstetrics, Gynaecology and Biotechnology of Animal Reproduction in 1998:
top row (from left to right) - Assistant Professors: G. I. Pidopryhora, V.S. Bryl, V.M. Lakatosh, V.M. Slepchenko, S. K. Yukhymchuk; bottom row (from left to right) - Professor, Corresponding Member of the Ukrainian Academy of Sciences V.A. Yablonskyi, Senior Laboratory Assistant T. H. Serdiuk, Associate Professor V.Y. Liubetskyi, Assistant Professor V. I.Borodynya, Associate Professor V.P. Polishchuk.
In 2000, graduates of the faculty Y. V. Zhuk and M. M. Mykhailiuk were invited to work as Assistants of the Department.

Fig.7. Department of Obstetrics, Gynaecology and Biotechnology of Animal Reproduction in 2000:
top row (from left to right) - Associate Professor V. M. Lakatosh, resident Y. G. Silaev, Associate Professors G. I. Pidopryhora, V.M. Slepchenko, assistants M.M. Mykhailiuk, Y. V. Zhuk; bottom row (from left to right) - senior laboratory assistant G. S. Plyashechko, Associate Professor V.I. Borodynya, Head of the Department, Doctor of Veterinary Sciences, Professor V.Y. Liubetskyi, Professor, Corresponding Member of the Ukrainian Academy of Agricultural Sciences V.A. Yablonskyi, Laboratory Assistant I.V. Kostiuk.

Fig. 8. The Department of Obstetrics, Gynaecology and Biotechnology of Animal Reproduction in 2003:
top row (from left to right) - Associate Professors V.M. Slepchenko, S. K. Yukhymchuk, V.M. Lakatosh, V.I. Borodynya, Assistant O.A. Valchuk, Medical Resident S.S. Amrosh, Associate Professor G. I. Pidopryhora; bottom row (from left to right) - senior laboratory assistant K.P. Soloshenko, professor V. A. Yablonsky, professor V.Y. Lyubetsky, laboratory assistant I.V. Kostiuk.

Personnel changes. In March 1998, Associate Professor V.Y. Lyubetskyi was appointed Head of the Department. In 1999, V. I. Borodynya was elected to the position of Associate Professor of the Department in a competition, Associate Professor V. S. Bryl retired, and V. M. Lakatosh entered doctoral studies. A graduate of the faculty O. A. Valchuk (2001) was hired as an assistant. After completion of postgraduate studies, the following persons were enrolled as assistants of the Department: from November 2004 - Y.V. Zhuk, from October 2005 - M.M. Mykhailyuk, from October 2006 - O.A. Valchuk. S.S. Derkach has been enrolled in the position of the resident doctor of the department since 2004.
Postgraduate studies. Enrolled in postgraduate studies of the department: Y.V. Zhuk (2001), M.M. Mykhailyuk (2002), O.A. Valchuk (2003), S.S. Derkach (2007).
Defense of PhD theses: M. M. Mykhailyuk (2006), O. A. Valchuk (2007).
Publications. During this period, the staff of the department published ..... works of conferences. In 2000, the department organized and held the First International Conference on the Physiology and Pathology of Animal Reproduction.
The Department in 2008-2017.
In 2009, the department employed 11 people (fig.9).

Fig. 9. The Department of Obstetrics, Gynaecology and Biotechnology of Animal Reproduction in 2009:
bottom row (from left to right) - laboratory assistant I.V. Kostiuk, Associate Professor V.I. Borodynya, postgraduate student L.V. Lozova. Lozova; middle row (from left to right) - postgraduate student S.S. Derkach, Associate Professor V.M. Slepchenko, Professor V.Y. Lyubetskyi,
Professor V.A. Yablonskyi, Associate Professor V.M. Lakatosh; top row (from left to right) - Assistant Y.V. Zhuk, Associate Professor M.M. Mykhailiuk, postgraduate student Y.V. Liubetskyi, Senior Lecturer O. A.Valchuk, postgraduate student V.M. Lozovyi.

Fig. 10. The Department of Obstetrics, Gynecology and Biotechnology of Animal Reproduction in 2013:
bottom row (from left) - resident doctor O. K. Pavlenko, associate professor V. I. Borodynya, senior laboratory assistant N. I. Shevchuk; middle row (from left) - Associate Professor V. M. Slepchenko, Professor V. Y. Liubetskyi, Professor V. A. Yablonskyi, Associate Professor S. S. Derkach;top row (from left to right) - Associate Professor O. A. Valchuk, Associate Professor Y. V. Zhuk, Assistant V. M. Mazur, Postgraduate Student A. V. Turchyk, Associate Professor V. M. Lakatosh

Fig. 2.11. Department of Obstetrics, Gynaecology and Biotechnology of Animal Reproduction in 2015:
bottom row (from left to right) - Associate Professor V. I. Borodynya, Professor V. A. Yablonsky, Senior Laboratory Assistant N. I. Shevchuk, postgraduate student Y. I. Masalovych; top row (from left to right) - Associate Professors V. M. Lakatosh, O. A. Valchuk,laboratory assistant M. V. Dolenko, senior lecturer V. M. Mazur, Professor V. Y. Lyubetskyi, Associate Professors Y. V. Zhuk, S. S. Derkach

Personnel complement. Elected to the positions of Associate Professors: M.M. Mykhailyuk (2008), O.A. Valchuk and Y.V. Zhuk (2010); V.V. Kovpak as senior lecturer (2014); and V.M. Mazur (2012) and S.S. Derkach (2013) as assistants. Resigned from their positions: M.M. Mykhailiuk (2012), V.M. Slepchenko (2013). In 2015, Doctor of Biological Sciences, Professor, Corresponding Member of the UAAS, Honoured Worker of Science and Technology of Ukraine, Member of the Verkhovna Rada of Ukraine of the II convocations (1994-1998), Vice-President of the World Association for Veterinary Education (1990-1998) V.A. Yablonskyi completed his scientific and pedagogical work at the Department and retired. Deceased: G. I. Pidopryhora (2008) and V.Y. Lyubetskyi (2017). In 2017, O.A. Valchuk was elected to the position of the Head of the Department of Obstetrics, Gynaecology, and Biotechnology of Animal Reproduction.
Since 2010, the Department's support staff has included senior laboratory assistants A. I. Blyzniuk (employee of the Department since 2010), N. I. Shevchuk (employee of the Department in 2012-2015), N. M. Filipenko (employee of the Department since 2017); laboratory assistants I. V. Shvets (employee of the department in 2011-2012), A. D. Semerunchyk (employee of the department in 2012-2013), M. V. Dolenko (employee of the department in 2013-2014); resident doctor O. K. Pavlenko (employee of the department in 2012-2015).
Postgraduate studies. Y. I. Masalovych (...) and Y. S. Masalovych (2015) were enrolled in full-time postgraduate studies.
Defence of PhD theses: Y. V. Zhuk (2009), O.V. Sibileva (2011), Y. S. Masalovych (2016).
Conferences. In October 2009, the department organised and held the II International Scientific and Practical Conference ‘Problems of Physiology and Pathology of Animal Reproduction’.
Publications. During this period, the staff of the department published ..... works.
The department in 2018 - 2025.
In 2018, the Department of Obstetrics, Gynaecology and Animal Reproduction Biotechnology employed 10 people (fig.12):

Fig. 12. Department of Obstetrics, Gynecology and Animal Reproduction Biotechnology in 2018:
bottom row (from left to right) - postgraduate student O.O. Zvedeniuk, Associate Professor V.I. Borodynya, resident doctor A.I. Blyzniuk, Head of the Department, Associate Professor O.A. Valchuk, postgraduate student D.I. Kravtsova, Associate Professor S.S. Derkach; top row (from left to right) - postgraduate student Y.S. Masalovych, senior laboratory assistant N.V. Filipenko, Associate Professors Y.V. Zhuk, V.M. Mazur, senior lecturer V.V. Kovpak, Associate Professor V.M. Lakatosh

Personnel changes. The following persons have been hired as assistants of the Department: Ivan Cheverda (2022) and Maksym Salizhenko (2023). On 30 June 2024, Associate Professor Valentyna Borodynya completed her scientific and pedagogical work at the department and retired after 35 years of scientific and pedagogical activity.
Changing the name of the department. On 1 March 2024, by the order of the Rector of NULES of Ukraine (№174 of 1.03.23), the Department of Obstetrics, Gynaecology and Animal Biotechnology was renamed to the Department of Veterinary Reproductive Sciences.
New laboratories: By the order of the Rector of NULES of Ukraine (№ 1248 of 2.12.2019), the Educational and Scientific Laboratory ‘Centre of Animal Reproduction with a Bank of Sperm and Embryos’ was established as part of the department. In April 2024, the department's scientific library was established, which has 3314 sources of specialized literature (the oldest of the publications dates back to 1928 and is the same age as the department).
Postgraduate students: M. Salizhenko (2018), B. Nyzhnyk (2019), Y. Lytvynchuk (2023), A. Lasiychuk (2024).
Thesis defenses: Yurii Masalovych (2020); PhD - Ivan Cheverda (2023), Ruslan Zaritskyi (2024).
Seminars, conferences, and round tables: jointly with the Department of Anatomy, Histology and Pathomorphology of Animals named after Academician V.G. Kasyanenko, a Ukrainian-Polish round table ‘Reproduction and Biomorphology of Animal Reproductive Organs’ was held with the participation of scientists from the Wroclaw University of Natural Sciences (2018). In September 2019 - International Scientific and Practical Conference ‘Animal Reproduction - Challenges of the Present’ (19-20 September 2019), dedicated to the 70th anniversary of Prof. V.Y. Lyubetsky. In November 2019, the Ukrainian-Polish scientific and practical seminar ‘Relevant issues of reproduction of dogs and cats’ was dedicated to the 100th anniversary of the Faculty of Veterinary Medicine of NULES of Ukraine. 8 December 2020 - a seminar on the occasion of the 90th anniversary of Professor Valentyn Andriiovych Yablonskyi. In October 2024 - a round table ‘Topical Issues of Veterinary Reproductive Medicine’, was dedicated to the memory of Professor V.Y. Lyubetskyi (1949-2017) on the occasion of the 75th anniversary of his birth.
Awards and honors: Associate Professors V. Borodynya and V. Lakatosh were awarded the Honorary titles ‘Honoured Scientific and Pedagogical Worker of NULES of Ukraine’ (2019); Associate Professor S. Derkach - Diploma of the Verkhovna Rada of Ukraine ‘For Merit to the Ukrainian People’ (2020); Assistant M. Salizhenko - Diploma of the National Security and Defence Council of Ukraine ‘For Personal Contribution to the Guarantee of Security and Defence of Ukraine and Cooperation with the NSDC of Ukraine’ (2021). ); Assistant M. Salizhenko - Diploma of the National Security and Defence Council of Ukraine ‘For personal contribution to the national security and defense of Ukraine and cooperation with the NSDC of Ukraine’ (2022). In June 2024, Associate Professor V. Kovpak was awarded the academic title of Professor of the Department of Obstetrics, Gynaecology, and Biotechnology of Animal Reproduction.
In March 2025, 11 employees worked at the Department of Veterinary Reproduction (fig.13).

Fig. 13. Department of Obstetrics, Gynaecology and Biotechnology of Animal Reproduction in 2025:

bottom row (from left to right) - resident doctor A. I. Blyzniuk, assistant professor Y. S. Masalovych, professor V. V. Kovpak, Associate Professor, Head of the Department O. A. Valchuk, Associate Professor S. S. Derkach, Senior Laboratory Assistant N. I. Shevchuk, Postgraduate Student Y. Lytvynchuk; top row (from left) - Assistant M. I. Salizhenko, Assistant I. M. Cheverda, Associate Professor V. M. Mazur, Associate Professor Y. V. Zhuk, Associate Professor V. M. Lakatosh, Postgraduate Student A. Lasiichuk