Comparative Evaluation of Biomechanical Characteristics of Acellular Dermal Matrix for Hernioplasty

Background. With the introduction of synthetic mesh implants into clinical practice, the recurrence rate of postoperative ventral hernias was signifi cantly reduced. The extensive use of synthetic implants led to the development of specifi c complications. The development of biological implants, based on extensively purifi ed decellularized collagen matrix of xenogeneic origin is highly relevant due to the fact that, unlike synthetic analogues, they have a biological origin and biodegrade in a natural way, gradually being replaced with newly formed connective tissue. The use of bioprostheses reduces the risk of complications.Objectives. To conduct a comparative evaluation of the biomechanical characteristics of acellular dermal matrix, obtained by detergent-enzymatic decellularization, and commercially distributed Permacol™ matrix.Methods. Acellular dermal matrix (ADM) was created by using samples of native skin of pig of Landras breed aged 4 months. The dermis was processed by means of detergent-enzymatic method. In order to evaluate and compare the mechanical properties of acellular dermal matrix, the biological samples were divided into 2 groups of 15 samples each. The fi rst group included acellular dermal matrix samples, the second group — native samples of pigs unprocessed dermis. The control group consisted of samples of PermacolTM Surgical Implant, xenotransplant for hernioplasty approved for use in the Russian Federation (Covidien, France). All samples were tested wet using universal testing instrument Instron 1122. MedCalc Statistical Software (Belgium) was used for statistical processing of the study results.Results. In the present study, pig dermis was processed using a detergent-enzymatic method to produce ADM. Routine histological examination confi rmed the removal of all cellular elements, and at the same time it was proven that the native structure of the dermis remained intact during its processing. The mechanical characteristics of xenogenic ADM were further determined. Its tensile strength was 9.1 ± 0.6 MPa (910 N/cm2 ), elongation to break was 21.1 ± 2.3%, and elastic modulus was 50.0 ± 1.6 MPa. These characteristics largely corresponded to the strength characteristics of native pig dermis and far exceeded the necessary physiological parameters. PermacolTM control was tested in two directions (longitudinal and transverse). In the longitudinal direction, the sample had higher mechanical characteristics: strength — 12.0 ± 1.7 MPa, elongation to break — 29.7 ± 2.4%, stiffness modulus — 47.2 ± 6.5 MPa. In the transverse direction, all indicators were 1.5–2 times lower.Conclusion. The developed xenogeneic biological implant in the form of ADM demonstrates rather good characteristics of plasticity, tensile strength and elasticity, to be used as a biological endoprosthesis for plasty of hernia defects of the abdominal wall of any size and shape

TYPES AND VARIETIES OF PINUS PUMILA (PINACEAE) ECOBIOMORPHES IN THE DERIVED STONE-BICH FORESTS OF THE MAGADAN REGION

Background. The study of the plants life form makes it possible to objectively assess the species significance in the vital activity of the plant community. In this respect, dwarf pine (Pinus pumila (Pall.) Regel) is of great interest, as it is the main species in the undergrowth of forests of the Extreme North-east of Russia. The goal of research is to explore the peculiarities of the formation of dwarf pine ecobiomorphs in the stone-birch-forests of the Northern Coast of the Sea of Okhotsk as an example of the species biomorphological adaptation to different ecological-cenotic conditions. Materials and methods. The studies were carried out on the southern macroslope of the Hasyn ridge in the Coastal-Okhotsk floristic region of the Magadan Region. The objects of research are the phytocenoses of four forest types of the stone-birch group of associations (Betuleta lanata pumilapinulosa) of middle and overripe age, which compose ecological and age pairs. In them, according to generally accepted methods of examining forest types, experimental plots were established, where forestry-geobotanical studies were carried out, the phytocenotic structure was explored, and the forms of growth and development of the model bushes were described in detail. Results. A brief history of the biomorphological study of dwarf pine was given. The formation and transformation laws of the species forms in dry and wet ecotopes for 20 years were studied. The previously unknown life features of the seasonal and age development of the dwarf pine were noted. Conclusions. Five main (bushy) and one rare (semi-tree-like) ecobiomorphs of dwarf pine and two kinds of its cupshaped ecobiomorph were identified. The light factor and micro-relief play decisive role in the formation of the dwarf pine ecobiomorphs. The typical ecobiomorphs of the species were defined: at a young age (up to 50 years) – compact roundish bush, in 50–70 years old –classic cup-shaped bush. For bushes older than 80 years the creeping ecobiomorph is characteristic, under the forest canopy – creeping with trunks, buried in the forest floor. In the most developed specimens of 70-80-year-old dwarf pine, secondary growth in terminal shoots was noted in years with abnormally warm autumn, while faults of skeletal branches-trunks by the fusion lines at the bush base – during periods of intense snowmelt in spring

SPATIAL STRUCTURE OF THE DERIVED OAK-FORESTS IN THE SOUTHERN PRIMORSKY TERRITORY

Background. The high anthropogenic load on forest vegetation in the southern regions of the Far East leads to the widespread replacement of native coniferous-broadleaf forests by low-value Quercus mongolica forests. The spatial structure study of these communities allows exploring their transformation processes during the restorative succession and revealing new regional features of the forest-forming process. The research goal is to study the spatial structure of the oak forests derivatives in the Southern Primorsky Territory, taking into account ecotopic conditions and anthropogenic impact. Materials and methods. The studies were carried out at key sites in oak forests located in two adjacent watershed basins at the southern slopes of the western Sikhote-Alin Mountains. The forests in one basin were completely cut down and then during the restoration they were regularly affected by fires. At the second site (plots with natural vegetation in the arboretum of the Mountain-Taiga Station of the Far Eastern Branch of Russian Academy of Sciences), the forests underwent selective felling and there were no fires. At both sites, forestry geobotanical studies were conducted according to the generally accepted Russian methods for examining forest types. The selection of coenoelements was carried out on the basis of solid mapping and detailed description of all plant tiers, analysis of the adificator ecobiomorphes. Results. At studied slopes, the forest cover with similar typological composition and identical phytocoenoses structure was formed. In the conditions of regularly recurring fires, the main part on the surface of the southern slopes is occupied by dry oak-forests, where xerophytic sedges and Asian cow-wheat are prevalent (from the watershed to the lower part of the slope). In the arboretum, fresh oak-forests with nemoral herbs dominate. More diverse oak ecobiomorphs composition and simple phytocoenoses structure are peculiar to dry oak forests. Conclusions. The structure formation in dry oak forests is determined by ecotopic and anthropogenic factors, in fresh oak forests – by ecotopic and coenotic. The degree of phytocenoses impairment and the features of anthropogenic impact play a significant role in the indigenous forests restoration. The forest-forming process is more advanced in forests, which underwent selective cutting and were not affected by fires. The developed undergrowth with predominant Manchurian hazelnut, petaloid-filament meadow-rue and Japanese chloranthus parcels, which are typical for indigenous forests, and no xerophytic parcels testifies to it. The study of the spatial structure is necessary as a basis for regional forest monitoring and reintroduction of former coniferous forest-forming species

Modern management technologies

Розглянуто теоретичні аспекти та надано практичні рекомендації щодо запровадження сучасних технологій управління у практичній діяльності підприємств. Рекомендовано для фахівців з питань управління підприємствами, викладачів, аспірантів, магістрантів та студентів економічних спеціальностей вищих навчальних закладів.Theoretical aspects were considered and practical recommendations were given regarding the introduction of modern management technologies in the practical activities of enterprises. Recommended for business management specialists, teachers, graduate students, master's students and students of economic specialties of higher educational institutions

Management decision-making technologies

Розглянуто теоретичні аспекти та надано практичні рекомендації щодо формування та реалізації технологій прийняття управлінських рішень. Рекомендовано для фахівців з питань управління підприємствами, викладачів, аспірантів, магістрантів та студентів економічних спеціальностей вищих навчальних закладів.Theoretical aspects were considered and practical recommendations were given regarding the formation and implementation of management decision-making technologies. Recommended for business management specialists, teachers, graduate students, master's students and students of economic specialties of higher educational institutions