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The article discusses the activities of the scientist and educator Isma‘il Gasprinsky in the field of education of Muslim peoples at the turn of the 19th-20th centuries. Gasprinsky is the author of the sound method of teaching (Phonics). He established elementary schools on the basis of this method. Such schools appeared not only in the central regions of Russia, but also in Turkestan, as well as in Turkey and India.The article describes the conditions, prerequisites and activities of some new method schools, dwells on the issue of opening a Jadid school in the city of Bombay.The author makes an attempt to determine the essence and methodological basis of the appearance of the sound method. This method was introduced by Gasprinsky into the educational practice of Muslim schools. Gasprinsky's sound method was based on the experience of European, Turkish and Russian schools and on the works of prominent scientists and teachers. Gasprinsky created his own teaching methodology based on European pedagogical traditions and Islamic values.

The article examines the process of Tatars studying abroad at the end of the 19th – beginning of the 20th centuries – in Bukhara, Samarkand, in the world centers for Islamic education – Istanbul, Cairo, Medina, Deoband. On the example of specifi c individuals, the prerequisites and some features of the learning process, including the issues of material support for students, as well as the further fate of the Tatars who graduated from these educational institutions, are described. Many graduates returned to their homeland and continued the work of their mentors. The most capable ones were invited as teachers to the madrasah that they themselves graduated from. The paper includes the results of the well-known Tatar scholar and theologian Shihab al-Din al-Marjani and the materials of the Tatar periodical press of the early 20th century. Many of the materials are introduced into scientifi c circulation for the fi rst time.

The publication examines the scientific activities of the famous archeographer, specialist in the field of oriental manuscripts and Tatar literature Fatkhiev, Albert Saitovich. A. Fatkhi is was born in the Aktanysh region of Tatarstan. His name is listed among the outstanding Tatar archaeographers of the last third of the twentieth century, such as M. Usmanov, M. Nugman, A. Karimullin, M. Akhmetzyanov and others. Albert Fatkhi is the author of four books. They contain descriptions of the manuscripts of Tatar writers and scholars. He wrote scientific articles on the problems of collecting and scientific processing of oriental manuscripts. He has works that discuss the problems of the Tatar literature, the contacts of the Tatars with other Turkic peoples in the field of literature and culture. The purpose of this study is to reveal A. Fatkhi’s contribution to the Tatar archaeography and philology.

Loneliness is a painful and alienating experience, which is an increasingly widespread phenomenon all over the globe. However, this phenomenon is perceived and interpreted differently in the world. The present study aims to compare the emotional, social, and romantic loneliness between Bulgarians and Russians. The two Slavic countries are historically and culturally close, but at the same time, there are many differences. Some studies have found that in the minds of both Russian and Bulgarian young people, loneliness is associated with both negative and positive aspects. This creates a common ground for the analysis and interpretation of this phenomenon in both countries. But the Russian people are more characterized by a positive-resource view of loneliness, while Bulgarian young people emphasize the negative. The study involved 608 people from Bulgaria and Russia aged 18-73 years. They completed the short version of the Social and Emotional Loneliness Scale for Adults by Di Tommaso E., Brannen C., Best L.A. (2004). The results indicated that „romantic loneliness“was108 the most pronounced and present with its frequency in the content of the overall experience of loneliness. This outlines deficits, expectations, and emotions that are realized / function / in the deeply personal world of the person, of the studied groups of adults both in Bulgaria and in Russia. In second place in terms of its representation is the "social loneliness", which ​​stands out among the studied adults from Bulgaria according to its marginal values. In the third place as third structural-content component is the "emotional loneliness", which is especially present in the experiences of the respondents from Bulgaria in comparison with those from Russia. Statistically significant results on the factors "country", “age” and "marital status" are also discussed.

Roll-over stability of tall buildings under wind loads is considered. The nonlinear nature of the problem is taken into account, including geometric, physical, and structural non-linearity. The problem is solved on the base of a system of linearized incremental equations of structural mechanics that describes the behavior of a system tall building - foundation soil. Several methods are examined for solving nonlinear problems of roll-over stability, specifically: 1) deformation method of systems equilibrium states tracing; 2) method of linearization of nonlinear equations and systems equilibrium states tracing; 3) method of linearization of nonlinear physical relations of a systems with constructive, static, geometric nonlinearity; 4) method of linearization of nonlinear physical relations of a system with constructive nonlinearity based on nonlinear incremental structural mechanics; 5) method of the deformation process tracing for a physically nonlinear soil base, given the increase of discharge zones and constructive nonlinearity. Each of these methods is used to solve a model task. These tasks take into account roll-over stability of high structures under action of wind loads. In general, the problem of roll-over stability of a high object can be represented as repeatedly nonlinear one with various types of non-linearity. In this regard, in the practice of high-rise buildings designing, it is necessary to develop scientifically and methodically substantiated methods of assessing roll-over stability, considering non-linear factors. Taking these factors into account will make it possible to assess the roll-over stability of a high-rise object more accurate.

The article is dedicated to extracurricular activities in Muslim women’s schools in Russia in the period before the October Revolution. These events were aimed at the comprehensive development, raising the cultural, intellectual level of students. They served the formation and preservation of religious-moral and national-cultural values among young Muslim women. The paper considers various types of activities that complement the curriculum of Muslim women’s schools in the early twentieth century. They contributed to the socialization of Muslim women in the new realities of the time. The article first introduced into scientific circulation new sources on the topic (materials of Tatar newspapers and magazines of the early twentieth century on the Arabic schedule).

The origin and potential role of chiral asymmetry remain one of the most exciting issues in biology. In this paper we review the chirality of biological macromolecules, starting at the level of single molecules and continuing to the level of supramolecular assemblies. We discuss the physical and chemical consequences of the presence of chirality and their role in the self-organization and formation of structural hierarchies in cells. Homochirality may serve as an essential factor that invokes mechanisms required to control the formation of discrete structural hierarchies in macromolecules and macromolecular assemblies. Symmetry is of fundamental importance not only for all molecular biology as a systemic factor of its organization but also for pharmacology, as well as a systemic factor of drug stereospecificity.

Present paper describes that adaptation of a questionnaire on the sociotropy or own assumptions and goals. Paper presents the results of the psychometric validity of the Russian adaptation of the Questionnaire for middle and older adults. Participants were adults aged 35-75 (N=358; M= 49,27; SD = 11,08; 75,5 % — females). Our adaptation was based on a New Zealand version of the “Socitropy/ Autonomy scale” by A. Beck. To check the criterial validity we used “Differential questionnaire of loneliness experiences”, “Social and emotional loneliness scales for middle and older adults”, “Psychological well-being scale by C. Ryff”. The results of the exploratory and confirmatory analysis identified four subscales: “Social non-confidence”, “Dependence on other’s opinion”, “Affiliation” and “Independence”. Psychometric tests proved that all identified scales had internal consistency, and form a general factor. Final confirmatory analysis showed that four scales are comparatively independent. Analysis of the results in age and sex groups showed that the questionnaire maintained its consistency in age groups (middle adulthood, later adulthood, aging) as well as for males and females. Thus, our results revealed that our adaptation could be used on adults and older adults in Russia.

This study aims to adapt and validate the Bulgarian version of the Social and Emotional Loneliness Scale on adults and older adults. We present the results of the psychometric assessment of the questionnaire on a sample of adults aged 35—75 (N=332; Mage=49.45; SD=11.17). Exploratory factor analysis revealed four factors: two factors were identical to the first two sub-scales, the third sub-scale split into two separate factors. Reliability of the new sub-scales was assessed with Cronbach’s α coefficient that showed high levels of reliability for the general scale (α=0.875) and for all four sub-scales (α ranged from 0.843 to 0.873). Confirmatory factor analysis proved the four-factor structure of the adapted scale. The convergent validity of the Social and Emotional Loneliness Scale was proved by correlation analysis with the Differential Questionnaire of Loneliness Experience. Our study yielded the adequate psychometric characteristics of the Social and Emotional Loneliness Scale for adults and older adults in Russia. In future research, we plan to increase the sample to standardize the scores for the scales.

The article highlights contribution of Tatar teachers in organizing Jadidist schools and educating children of the local peoples in Turkestan. Opinions of scientists of the early twentieth century, the Soviet period, and also modern researchers on this problem are presented. Based on the materials from newspapers and magazines of the early 20th century in the Tatar and Uzbek languages, the article highlights the history of the opening of certain schools and their activities. The issues of the the local population representatives’ attitide to the work of Tatar teachers are revealed. In addition, the role and influence of Tatar teachers and their textbooks on publishing educational literature written in the Turkestan peoples’ languages is also emphasized.

The article analyzes the famous Tatar scholar, teacher, enlightener, and public figure Riza Fakhreddin’s opinion on Muslim national and religious schools. Fakh-reddin’s publications published in the Tatar periodical in 1913–1914 served as a source for writing the work. In 1913, Mufti M.Sultanov received an official letter from the Department for Foreign Confessions of the Ministry of Internal Affairs of Russia. The letter requested Muslims’ opinions about the situation of religious schools from the Islamic perspective. In his works, Fakhreddin gives the questionnaire answers and covers the Muslim community's opinion about this document.

—The suprachiasmatic nucleus (SCN) regulates the functioning of the body in accordance with circadian rhythms thanks to the pacemaker neurons present in it and afferents modulating these neurons. One of the afferents is represented by nerve fibers containing only the first enzyme for the synthesis of catecholamines, tyrosine hydroxylase (TH). In ontogeny, the concentration of these fibers (amount per unit volume of tissue) reaches a maximum on the 10th postnatal day (P10), and then gradually decreases. The aim of this work was to verify our assumption that, in TH-containing fibers in SCN of rats, L-DOPA is synthesized from L-tyrosine as the final secretory product, and the efficiency of this synthesis is higher in the early postnatal period than in adults. The synthesis of L-DOPA was evaluated by an increase in the total content of L-DOPA in SCN and in the incubation medium after a two-hour incubation of SCN in a medium with or without L‑tyrosine. We found that the addition of L-tyrosine to the incubation medium led to a multifold increase in the total L-DOPA content in SCN and in the medium, which is evidence of the synthesis of L-DOPA as a final product in TH-containing fibers. A comparative analysis of the synthesis of L-DOPA in SCN at P10 and P60 showed that the synthesis rate (a ratio between the total content of L-DOPA in SCN and in the incubation medium to the incubation time) at P60 exceeds the synthesis rate at P10, while the efficiency of L‑DOPA synthesis (a ratio between the rate of L-DOPA synthesis and the total protein content in SCN) is higher at P10. Thus, we obtained evidence of L-DOPA synthesis in TH-containing SCN nerve fibers, and the efficiency of this synthesis in rats in the early postnatal period is higher than in adult animals.

—The suprachiasmatic nucleus (SCN) regulates functions in accordance with circadian rhythms thanks to the pacemaker neurons present in it and afferents modulating their activity. One type of afferent is nerve fibers containing only tyrosine hydroxylase (TH) and secreting (L-dihydroxyphenylalanine) L-DOPA. The aim of this work was to test the hypothesis that L-DOPA comes from TH-containing fibers into neurons containing only aromatic L-amino acid decarboxylase (AAAD), where dopamine is synthesized. The synthesis of dopamine was evaluated by its content in SCN in intact rats on the 10th postnatal day (P10) and on P60, as well as by the total dopamine content in SCN and in the incubation medium after incubation of this nucleus in the medium with or without L-DOPA. It was shown that in intact rats SCN contains dopamine at the same concentration at P10 and P60. Some of the experiments with incubation of SCN slices were performed with rats injected with neurotoxins of monoaminergic neurons to exclude the synthesis of dopamine from L-DOPA in monoaminergic structures. At P10, during incubation of SCN in L-DOPA-containing medium, an increase in dopamine synthesis was observed equally in animals in control (normal) and after exposure to neurotoxins, which indicates synthesis of dopamine only in monoenzymatic AAAD-containing neurons. In a similar experiment at P60, the addition of L-DOPA into the incubation medium also led to an increase in the synthesis of dopamine, however, in animals exposed to neurotoxins to a lesser extent than in the control. This means that in adult animals, dopamine is synthesized in SCN mainly in monoenzymatic AAAD-containing neurons and to a lesser extent in monoaminergic structures. Thus, it was shown that dopamine in SCN is synthesized in monoenzymatic AAAD-containing neurons from L-DOPA secreted by monoenzymatic TH-containing fibers.

—A unified system of classification of levels of molecular structures of a living cell as the hierarchy of alternating-sign chiral structures that reflects the physical (thermodynamic/entropic) basis of intramolecular and supramolecular folding is proposed and substantiated. The tendencies for intermolecular chiral correspondences characteristic of the interactions between macromolecules of the same and different types at the corresponding levels of molecular organization (for protein–protein, L–L; for nucleic acids, DNA–RNA, D–D; protein–nucleic acids, L–D; and proteins and nucleic acids with L-lipids of membranes, according to the sign of chirality of the corresponding level of organization of the structure of macromolecules) were identified.

The article discusses certain moments of Tatarstan period of life and work of the famous Crimean Tatar scientist, poet and teacher Kerim Jamanakli. He made a great contribution to the development of literature and pedagogy of the Crimean Tatars and Kazan Tatars. The article describes the activities of Kerim Jamanakli in training teachers for national schools of Tatarstan. The last 20 years of his life he taught at the Elabuga Pedagogical Institute.

The article analyzes and describes the journalistic reception of Mariengof’s prose from the 1980s to 2019. After the scandal around the „Novel without Lies” in 1927–1929, the return of Mariengof’s prose to the general reader and, consequently, the interpretation by literary critics, took place in several stages. After a long pause, the Mariengof’s prose was published in 1988 and then republished many times. In 2000–2010, a new wave of study and rethinking of the writer’s work began – thanks to the writer Z. Prilepin and researcher O. Demidov. The author gives a brief description of the reception of the publication in 1965. The author subjects the key publications about Mariengof’s prose, which were published in 1988-2019 in such publications as “Book Review”, “Literary Review”, “Neva”, “Our Contemporary”, “New World”, “Free Press”, etc. to detailed description and analysis. Each of the stages is analyzed by the author separately, and at the end he sums up how the image of Mariengof in journalistic texts has changed from perestroika to the present day.

This work is dedicated to proving our hypothesis that catecholamines and their metabolites play a crucial role in the development of retinopathy of prematurity, which leads to progressive uncontrollable vascularization in the retina, leading to blindness. The study was performed in an animal model of retinopathy of prematurity, which was achieved by hyperoxygenation in rats on postnatal days 7, 14, 21, and 30. The content of catecholamines and their metabolites in the retina of rats was determined by high performance liquid chromatography with electrochemical detection. It was shown that, in the rats with retinopathy, the content of L-DOPA on days 21 and 30 was decreased as compared to the control, whereas the content of noradrenaline on day 14 life increased compared to the control. However, we did not observe changes in the content of dopamine in the experimental animals relative to the control in any period studied. Given the published data on the involvement of catecholamines in the regulation of vasculogenesis in the retina in normal state, our data on the changes in the catecholamine metabolism in the retina in the model of retinopathy of prematurity can be regarded as evidence of the important role of catecholamines in the pathogenesis of this severe disease.

The development of individual organs and the whole organism is under the control by morphogenetic factors over the critical period of morphogenesis. This study was aimed to test our hypothesis that the developing brain operates as an endocrine organ during morphogenesis, in rats during the perinatal period (Ugrumov in Neuro Chem 35:837-850, 2010). Norepinephrine, which is a morphogenetic factor, was used as a marker of the endocrine activity of the developing brain, although it is also secreted by peripheral organs. In this study, it was first shown that the concentration of norepinephrine in the peripheral blood of neonatal rats is sufficient to ensure the morphogenetic effect on the peripheral organs and the brain itself. Using pharmacological suppression of norepinephrine production in the brain, but not in peripheral organs, it was shown that norepinephrine is delivered from the brain to the general circulation in neonatal rats, that is, during morphogenesis. In fact, even partial suppression of norepinephrine production in the brain of neonatal rats led to a significant decrease of norepinephrine concentration in plasma, suggesting that at this time the brain is an important source of circulating norepinephrine. Conversely, the suppression of the production of norepinephrine in the brain of prepubertal rats did not cause a change in its concentration in plasma, showing no secretion of brain-derived norepinephrine to the bloodstream after morphogenesis. The above data support our hypothesis that morphogenetic factors, including norepinephrine, are delivered from the developing brain to the bloodstream, which occurs only during the critical period of morphogenesis.

According to the literature, the cerebrospinal fluid (CSF) in the cerebral ventricles contains numerous neuron-derived physiologically active substances that can function as neurohormones and contribute to volume neurotransmission in the periventricular region of the brain. This study was aimed at carrying out a comparative analysis of CSF and the blood levels of monoamines in rats during ontogenesis as an indicator of age-related characteristics of monoamine transport to body fluids and their function as neurohormones in volume neurotransmission in the periventricular region of the brain. We have shown that CSF in the perinatal period and adulthood contains the most functionally significant monoamines: dopamine, noradrenaline, and serotonin. A comparison of the monoamine levels in the CSF and blood of animals of different age groups revealed that CSF contains monoamines of predominantly neuronal (cerebral) origin and almost no monoamines derived from the general circulation. We also established that monoamines are found in the CSF at physiologically active levels that allow them to act as neurohormones in both reversible volume neurotransmission in the adult brain and irreversible regulation of brain development in the perinatal period.

Aim: to study daily stress (DS) in adults by gender and city of residence. Methods: the study involved 334 adults aged 20-60, 158 subjects from Arkhangelsk, 176 - from St.-Petersburg. Instruments: Inventory of daily stressors, Scale of Perceived Stress-10 (FWS) and the survey. Results revealed high level of DS in all studied domains. Professional domain was the most stressful (М = 27,23 for Arkhangelsk and М = 26,07 fro St.-Petersburg). We identified a greater amount of DS in all domains, higher levels of stress (М = 16,8; SD = 5,09) and perceived stress (М = 31,2; SD = 5,46) in women compared to men (М = 13,7; SD = 4,74 и М = 28,3; SD = 5,58). In men, the most stressful were the professional (М = 23,69; SD = 22,74), financial domain (М = 17,02; SD = 21,00), the domain of interpersonal communication (М = 14,87; SD = 18,98) and the domain of the external environment problems (М = 15,05; SD = 15,01); for women - professional (М = 28,29; SD = 21,92), emotional, personal (М = 27,58; SD = 27,48) and economic domains (М = 22,71; SD = 24,57). The differences were found in a larger number of stressors in the domain of family interaction and household needs for Arkhangelsk; and more stressful financial, emotional and personal domains and domain of the external environment - for St.-Petersburg. Conclusions: comparison of the DS showed that for Arkhangelsk domains of family interaction and household were more stressful, while for St.-Petersburg financial problems, environmental problems and a sense of loneliness were more urgent. The correlation analysis showed that individual psychological features play an important role in the perception of stressors. The further directions of the research in this field should be focused on the comparison of stressors with the parameters of psychophysiological and personal functioning.

The present paper considers daily hassles in different life domains, reveals their connections to the level of strain and perceived stress, investigates the role of psychological well-being and life satisfaction in the perception of the number of stressors and strain caused by stress. Methods: Inventory of daily stressors (Petrash et al.), Scale of perceived stress (Ababkov et al.), Psychological well-being scale (C. Ryff), Life satisfaction scale (E. Diener), a survey on satisfaction with different life domains. Sample: 334 adults aged 20—60 (118 males, 216 females). Results revealed hassles in all the life domains. Most pronounced hassles in women were those related to health, loneliness, competitiveness, job; most pronounced hassles in men were job-related, financial, health and family stressors. Perception of daily hassles was associated with an increase in the levels of stress overstrain and perceived stress. The number of stressors and the level of overstrain was higher in women. Psychological well-being, subjective well-being, and financial satisfaction were shown to be direct positive predictors of the number of perceived hassles and the level of overstrain.

A labeled norepinephrine analogue was prepared by bromination of norepinephrine with subsequent debromination with tritium or deuterium gas. The yield of tritiated norepinephrine was 10–20% with a molar radioactivity of 27 Ci/mmol. The biological activity of tritiated norepinephrine was evaluated by analyzing its specific capture by noradrenergic neutrons in thick sections of the brainstem and midbrain of Wistar rats, and in a suspension of cells of pheochromocytoma PC12 expressing the membrane transporter of norepinephrine. It is shown that tritium-labeled norepinephrine synthesized by the proposed method does not differ in biological activity from the natural norepinephrine.

The paper presents the results to the preliminary validation of the Health-Promoting Lifestyle Profile (HPLP-II; Walker, et al., 1987, 1996) on the Russian sample. 443 participants from Saint Petersburg, aged from 17 to 65, were involved in the study (136 males; 307 females). HPLP II showed high internal consistency in the whole sample (Cronbach’s α=0,888) and in age and gender subgroups (Cronbach’s α ranged from .850 to .898). In order to test the convergent validity of the questionnaire, we used: scales from the questionnaire of a healthy lifestyle, Big Five Personality Test, Ryff’s Psychological Well-being Scales, SF-36 Short Form Health Survey, Type of Attitude to the Disease questionnaire. The resulting correlations confirm the convergent validity of the profile. The HPLP II had satisfactory preliminary psychometric properties. It can be used to assess the health-promoting lifestyles on a Russian sample.

The aim of this study was to investigate the molecular-genetic mechanisms of noradrenaline synthesis in the rat brain during the critical period of morphogenesis. For this purpose, the level of gene expression and the contents of the enzymes for noradrenaline (NA) synthesis, tyrosine hydroxylase (TH), and dopamine-β-hydroxylase were evaluated. We have shown that the mRNA level of these enzymes remains at a stable high level in the perinatal period of ontogeny and decreases slightly by the end of the first month of life. The contents of these enzymes in the brain have a different age dynamics: the content of TH, a rate-limiting enzyme of NA synthesis, is constantly growing, which, along with the constant level of its mRNA, may indicate the predominance of regulation of the TH synthesis at the translation level during this period. However, the content of dopamine-β-hydroxylase and its mRNA does not change during the perinatal period.

The study is devoted to investigating the humoral interaction of the organs that are major sources of the morphogenetic factor noradrenaline in the general circulation system of rats in the neonatal period of development. The change in the synthesis of noradrenaline in the central and peripheral organs when its synthesis in the brains of neonatal rats is switched off was considered as one of the mechanisms of such interaction. For this purpose, the level of gene expression and the content of enzymes involved in the synthesis of noradrenaline—tyrosine hydroxylase (TH) and dopamine-β-hydroxylase (DBH)—was determined in the brain, adrenal glands, and the organ of Zuckerkandl. The synthesis of noradrenaline after destruction of noradrenergic neurons was switched off by injecting anti-DBH-saporin-antibodies against dopamine-β-hydroxylase conjugated to the cytotoxin saporin into the cerebral ventricles of neonatal rats. The content of TH and DBH mRNA in organs was determined by realtime PCR, and the protein content of enzymes was determined by Western blotting. It is shown that, 48 h after switching off the synthesis of noradrenaline in the brain of 2-day-old animals, a sharp increase in TH and DBH mRNA content in adrenal glands and the organ of Zuckerkandl was observed, although the content of both enzymes was retained at the control level. These data indicate a compensatory enhancement of expression of the genes encoding noradrenaline synthesis enzymes at the transcriptional level as a result of humoral interaction of central and peripheral sources of noradrenaline in the neonatal period of ontogeny.

Gene expression and content of the key enzymes involved in the synthesis of noradrenaline-tyrosine hydroxylase and dopamine beta-hydroxylase-was evaluated in the organ of Zuckerkandl of rats in the critical period of morphogenesis. High levels of mRNA and protein of both enzymes in the perinatal period of development and their sharp decline on day 30 of postnatal development were detected. These data indicate that the synthesis of noradrenaline in the organ of Zuckerkandl is maximum during the critical period of morphogenesis and decreases during the involution of this paraganglion.

This work is aimed at studying the mechanisms of reciprocal humoral regulation of noradrenaline-producing organs in rats in the perinatal period of development. The activity of noradrenaline synthesis enzymes tyrosine hydroxylase and dopamine-beta-hydroxylase was measured in the brain and adrenal glands 48 and 72 h after the injection of immunotoxin (anti-dopamine-beta-hydroxylase-saporin) into the rat brain ventricles. It was shown that, 48 h after the immunotoxin injection into the brain, the activity of tyrosine hydroxylase in the brain decreased; however, 72 h after the injection it reached the control levels. This fact indicates that noradrenaline synthesis in the survived neurons increases. In the adrenal glands, 72 h after the immunotoxin injection into the brain, the activity of dopamine-beta-hydroxylase increased. This points to a compensatory increase in the rate of noradrenaline synthesis in the adrenal glands when the synthesis of noradrenaline in the brain is inhibited.

Loneliness has been considered a major challenge since long before the pandemic. Changes caused by the COVID-19 pandemic included modifications in social communications and activities. Thus, it was expected that loneliness would increase during the pandemic. The first studies of loneliness during the pandemic revealed inconsistent results. We hypothesized that physical isolation led to changes in the quality of relationships, thus, loneliness trends could be different from those predicted. For our study we used methods to measure loneliness: the Social and Emotional Loneliness Scale (SELSA-S) for Adults and Older Adults, the Multidimensional Inventory of Loneliness Experience, and demographic data. Participants were middle-aged and older middle-aged adults (n = 457) aged 35–59 (M = 45.5, SD = 6.88, 35.4% males). Participants came from two studies: Study 1 consisted of 280 participants aged 35–59 (M = 44.8, SD = 6.93, 29.6% males), the study was conducted before the pandemic in late 2019, participants in Study 2 were adults (n = 177) aged 35–59 (M = 46.5, SD = 6.68, 44.6% males), data were collected in the fall of 2020. The results did not confirm increase in loneliness, moreover, participants reported lower scores of loneliness in some domains. Regression analyses showed that general experience of loneliness was predicted by different loneliness characteristics in pre-pandemic and pandemic age groups. We found some similar mechanisms that were activated within different situations. Our results confirmed the complex nature of loneliness, they argue that pandemic effects were not limited to increase in loneliness and that the mechanism of loneliness can adjust to environmental factors.

The aim of the investigation was to study a systemic level of L-DOPA, dopamine, and norepinephrine, and assess their prognostic value in retinopathy of prematurity (ROP) development on an experimental disease model. Materials and Methods The investigation was carried out on infant Wistar rats (n=36) divided into a study group (rat infants with experimental ROP, n=17) and a control group (n=19). The animals of both groups were sacrificed on days 14, 21–23, and on days 28–30. The choice of the indicated periods corresponded to the key stages of ROP development in an experiment and was based on the findings of our previous histological studies. Dopamine, L-DOPA, and norepinephrine levels in infant rat blood plasma samples were determined. Results On day 14 of the experiment (the period corresponds to the pathological neovascularization induction in the applied model and preclinical ROP in children), mean L-DOPA level in infant rats with ROP (0.31 ng/ml) was significantly decreased compared to that in the controls (0.42 ng/ml) (p≤0.01). On days 21–23 of the experiment (the period corresponds to the growth of pathological extraretinal neovascularization in the applied model and ROP stage 3 in children) the systemic level of L-DOPA was still statistically reduced in the study group (0.87 ng/ml) compared to the control group (1.53 ng/ml) (p≤0.01). On days 28–30 of the experiment (the period corresponds to the regress of neovasculature in the applied model and a spontaneous ROP regress stage in children) the L-DOPA level in blood plasma in the study group (0.33 ng/ml) showed an insignificant upward tendency in reference to the controls (0.21 ng/ml). Mean dopamine and norepinephrine levels had no difference in the groups under study of infant rats within all follow-up periods. Conclusion Low systemic level of L-DOPA at the preclinical stage of experimental ROP should be considered as a laboratory prognostic criterion of a developing pathological process; it will enable to use the criterion when working out the measures to optimize the existing screening system for the disease in children.