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Introduction. Currently, the purification of wastewater and technological solutions by membrane methods is considered a promising way to neutralize liquid waste. Therefore, the task of developing an engineering method for calculating baromembrane devices is a challenge. Studies on methods involving calculation of design and process variables, membrane equipment design, research of technological features of membrane devices, selection of design schemes, as well as methods of strength and rigidity analysis, are investigated.Materials and Methods. Basic elements of the body of the combined membrane apparatus are considered, a design scheme is proposed, and a method for calculating the strength and rigidity of the main load-bearing element, the cover, is described. Results. The methods determine the required dimensions of shells and plates for the development of a combined membrane apparatus, and evaluate the strength properties of the devices of this class. The construction elements of the apparatus (primarily, the load-bearing covers) must meet not only the requirements of efficiency and quality of separation and cleaning of solutions, but also the conditions for safe operation. Therefore, the design of the device covers should be based on the optimal design dimensions (thicknesses of round plates, toroidal shells, and support rings). To test the method, the stress-strain state of the membrane apparatus structure was calculated for strength and rigidity. As an example, we consider one cover presented in the form of an open toroidal shell. The evaluation of the application of this technique, taking into account the fact that the shell is mated with a round plate in the inner diameter, and with a ring in the outer diameter, has provided the determination of the required parameters.Discussion and Conclusions. The obtained method of analytical description of the mechanical impact on the elements of the combined apparatus and the example of calculating the toroidal shell and plate, enables to evaluate the stressstrain state of the structure for strength and rigidity. The results of the calculation of covers made of various materials at different pressures are presented. Loading the combined apparatus with transmembrane pressure made it possible to determine the required dimensions of the shells and plates for its design and development.

Introduction. The paper considers analytical studies on the “rotor – gapped-type support” dynamic system under process loading. The research objective is to obtain expressions for determining the equivalent stiffness characteristics of the system.Materials and Methods. A rotor rotating in the elastic gapped-type supports is considered. A dynamic model that enables to consider the problem of determining the linear equivalent stiffness characteristics of mounting groups is pro-posed. To solve the problem, a system of differential equations is compiled, and a detailed analysis is performed.Results. From the obtained dynamic equations of the system in question, we can calculate the static angular deviation of the rotor pins due to the action of the load. The proposed expressions for determining equivalent stiffness characteristics testify that it is possible to study the rotor dynamics as on the linear elastic supports with the above parameters. The obtained system of equations is analyzed, and all special cases of applying the first approximation formulas for equiva-lent stiffness of the rotor mounting groups are listed.Discussion and Conclusions. The results obtained make it possible to study many dynamic processes on the basis of linear differential equations considering the nonlinear properties of the system. For shavers used in the production of leather materials, the determination of rotor vibrations in the horizontal plane provides the quality and accuracy of operations.

Justification of the study. The normalization of vitamin D levels in both children and adults is the goal of numerous studies around the world, and the setting of a number of objectives related to this vector of preventive medicine, dictates the need for a more detailed study of regional features of the status of calcidiol and the identification of both risk factors and risk groups. Aim of the study: to analyze the impact of risk factors on the provision of vitamin D to adolescents in the Moscow region. Methods: 360 children over 11 years of age (average age was 14.74 ± 1.92 years) who attended a children’s polyclinic for preventive check-ups or are under observation in a day-care centre. After the examination, all schoolchildren were determined to have serum content of calcidiol – active metabolite of vitamin D. Results: the analysis revealed low vitamin D levels in children, with a median of 16.1 ng/ml. Normal vitamin D levels were found in only 6.7% of cases. The following risk factors for vitamin D deficiency were identified in Moscow schoolchildren: time of year (p < 0.001), inclusion of such foods as fish (p = 0.021) and liver (p = 0.036), gastrointestinal pathology (p < 0.001), endocrine system pathology (p < 0.001), musculoskeletal system pathology (p = 0.045): course of chronic inflammatory process (p = 0.01) in the body. The correlation between acute respiratory diseases and calcidiol supply was analyzed: at low frequency of acute respiratory infections during the year, the median level of vitamin D was 17.1 ng/ml (Q1-Q3: 12.6-22.1 ng/ml), at an average frequency – 11.4 ng/ml (Q1-Q3: 8.45-16.05 ng/ml), at high frequency – decreased to 7.94 ng/ml (Q1-Q3: 5.89-9.06 ng/ml). Conclusion: Vitamin D deficiency prophylaxis should be provided to children all year round, without a break for the summer months. If a child has a risk factor for vitamin D deficiency, the metabolite correction should be controlled by the calcidiol serum content.

Premature infants are referred to the specific risk group for developing iron deficiency anemia (IDA). Depending on the time of occurrence and pathogenetic mechanisms, anemia in premature infants is classified into several types among which only late anemia is characterized by iron deficiency. The article tells about the causes and development mechanisms of IDA in premature infants, as well as the methods of prevention and treatment. The focus is on the prevention of late anemia in premature babies through administration of iron preparations.

The article presents data on prevalence structure and causes of iron-deficiency conditions (IDC) in adolescents. The authors describe both literature data and the findings of their own study in the adolescents (n = 337) studying at Moscow comprehensive schools. Iron- deficiency anemia was revealed in 5.3% of the examined adolescents, latent iron deficiency — in 17%; vast majority of the last were females. The authors also determined the most common causes of IDC development in adolescents: growth spurt (according to the anamnesis), a source of chronic blood loss (prolonged and abundant menstruations [in girls], frequent nasal bleeding), vegetarianism, intense physical activity, diet compliance, excess weight, and obesity.

Goal. Study of vitamin D sufficiency in children of puberty and pre-puberty age in Moscow. Methods. We examined children aged from 10 to 17 years living in Moscow. In order to appraise seasonal changes in the blood vitamin D status, we determined the average level of the main vitamin D metabolite — 25(OH)D — in different months of the year. The criteria for involving children into a laboratory examination were age (11–17 years), absence of organic or genetic pathology, permanent residence in Moscow, no intake of calcium and active vitamin D metabolite preparations at the time of examination. Results. The study involved 360 children (i. e. 30 children were examined every month) aged from 10 to 17 years. Analysis of the obtained data demonstrated differences in vitamin D sufficiency in the examined children in winter, spring, summer and autumn months. The serum concentration of vitamin D was significantly higher in summer months than in winter months. We did not reveal sex-related differences in vitamin D sufficiency among Moscow adolescents. Diet evaluation demonstrated that children extremely rarely consume fish as the main food source of vitamin D. Conclusions. Special attention should be given to the development of effective methods of correction of low vitamin D status and prevention thereof. Maintenance of the optimal vitamin D status in winter is infeasible due to insufficient exposure to sunlight, short duration of children’s walking during the schoolyear and absence of cholecalciferol sources in children’s diets. Special attention should be given to vitamin D intake by means of prescribing enriched food additives.

Iron deficiency (ID) is a common disorder worldwide, hence physicians of virtually all specialities must know about the disease. Knowledge of iron deficiency anemia (IDA) and latent iron deficiency (LID) is especially relevant for practicing pediatrician. The article tell about the national and foreign research on the prevalence of IDA and LID. The most significant factors contributing to the prevalence of ID among different population groups are discussed: sex, age, ecological, physiological, social and economic factors.

In 90% of infants, the introduction of complementary foods or transition to bottle or mixed feeding is characterized by changes in the frequency and type of stool, intestinal colic, regurgitation, flatulence. Administration of the multi-strain probiotic Bac-Set Baby for 14 days in infants with FGID allows to manage the changes in the frequency and type of stool in 80% of cases, symptoms of intestinal colic in 86% of children, regurgitation in 70%, and flatulence in 78% of children. Studies of the metabolic activity of obligate intestinal microorganisms demonstrated that multi-strain probiotic Bac-Set Baby (Probiotics International Ltd., UK) in children with FGID is effective in the management and restoration of the intestinal microbiota in children in the first year of life. The administration was associated with a tendency to restore the activity of the colonic obligate microflora, particularly bifido- and lactobacteria, due to changes in the qualitative composition of microorganisms characterized by reduced activity of facultative and residual anaerobic (in type 1) and aerobic (in type 2) microfloras, and improvement of the intraluminal environment. In addition, there was a tendency toward normalization of proteolysis and elimination of residual (opportunistic) microorganisms as a result of treatment.

Diseases of the gastrointestinal tract (GIT) are the 2nd most widespread pathology in children today. According to various authors, functional disorders of the gastrointestinal tract (FDGIT) are found in 65--75% of children depending on the age and are caused by the formation of the motor and secretory functions of the gastrointestinal tract. The clinical pattern is dominated by abdominal pain [1, 2, 3].

The article presents features of physiological processes and pathological conditions in under one-year children that predispose the development of iron-deficiency anemia. Basic methods of iron deficiency prophylaxis and principles of iron drug selection and dose selection for iron-deficiency anemia treatment for children in the stated age category are described in the article. Particular attention is paid to the prevention and treatment of iron deficiency anemia in preterm infants; foreign and domestic recommendations on this issue are presented. A practicing pediatrician needs to know the features of the disease’s development and treatment caused by differences in physical conditions accompanied by a high activity of metabolic processes and the immaturity of the young patients’ anatomic structures in order to identifiy and select the right iron-deficiency anemia treatment strategy.