Nanometric Hydroxyapatite Particles as Active Ingredient for Bioinks: A Review

Additive manufacturing (AM), frequently cited as three-dimensional (3D) printing, is a relatively new manufacturing technique for biofabrication, also called 3D manufacture with biomaterials and cells. Recent advances in this field will facilitate further improvement of personalized healthcare solutions. In this regard, tailoring several healthcare products such as implants, prosthetics, and in vitro models, would have been extraordinarily arduous beyond these technologies. Three-dimensional-printed structures with a multiscale porosity are very interesting manufacturing processes in order to boost the capability of composite scaffolds to generate bone tissue. The use of biomimetic hydroxyapatite as the main active ingredient for bioinks is a helpful approach to obtain these advanced materials. Thus, 3D-printed biomimetic composite designs may produce supplementary biological and physical benefits. Three-dimensional bioprinting may turn to be a bright solution for regeneration of bone tissue as it enables a proper spatio-temporal organization of cells in scaffolds. Different types of bioprinting technologies and essential parameters which rule the applicability of bioinks are discussed in this review. Special focus is made on hydroxyapatite as an active ingredient for bioinks design. The goal of such bioinks is to reduce the constraints of commonly applied treatments by enhancing osteoinduction and osteoconduction, which seems to be exceptionally promising for bone regeneration.

ASSESSMENT OF THE SOUTHERN URALS RECREATIONAL POTENTIAL FOR THE DEVELOPMENT OF THE AKTOBE TOURISM INDUSTRY

Tourism is a sphere of the social and economic complex, which is gradually turning into a developing industry. The importance of tourism development for the economy of Kazakhstan as a whole is essential. This scientific article is devoted to the assessment of the promising areas recreational potential of the Aktobe regions tourist activity. The study geographically describes the research area, the pattern of natural and climatic conditions, the uniqueness of landscapes and the complexity of their spatial and temporal organization. The units of physical-geographical or economic-geographical zoning serve as an objective basis for assessing territorial combinations of natural conditions and resources. The scientific work gives a brief description of the natural conditions, geomorphological and floral composition of the Southern Urals territories that are promising for recreational tourism. The article presents the factors reflecting the attractiveness of the region for the creation of specially protected natural areas.

Self-consistent migration puts tight constraints on the spatio-temporal organization of species-rich metacommunities

Biodiversity is often attributed to a dynamic equilibrium between immigration of species and competition-driven extinction. This equilibrium forms a common basis for studying ecosystem assembly from a static reservoir of migrants—the mainland. Yet, natural ecosystems often consist of many coupled communities (i.e. metacommunities) and migration occurs between these communities. The pool of migrants then depends on what is sustained in the ecosystem, which in turn depends on the dynamic migrant pool. This chicken-and-egg problem of survival and migration is poorly understood in communities of many competing species, except for the neutral case - the "unified neutral theory of biodiversity". Employing spatio-temporal simulations and mean-field analyses, we show that self-consistent migration puts rather tight constraints on the dynamic migration-extinction equilibrium. When the number of species is large, even weak competitions push species to the edge of their global extinction, such that the overall diversity is highly sensitive to perturbations in demographic parameters, including growth and dispersal rates. When migration is short-range, the resulting spatio-temporal abundance patterns follow broad scale-free distributions that correspond to a directed percolation phase transition. The qualitative agreement of our results for short-range and long-range migration suggests that this self-organization process is a general property of species-rich metacommunities. Our study shows that self-sustaining metacommunities are highly sensitive to environmental change and provides insights into how biodiversity can be rescued and maintained.

Review: Chronopharmacology; A Biological Rhythm

Chronopharmacology is the study of how the effects of drugs vary with biological timing and endogenous periodicities. The goal is to improve our understanding of periodic and thus predictable (e.g. circadian) changes in both desired effects (chronoeffectiveness) and tolerance (chronotolerance) of medications. Dosing time-dependent changes also include quantification of parameters characterizing endogenous circadian rhythms (CR), in terms of pharmacologic effects, e.g. the 24-h adjusted mean (M), the period , the amplitude (A, the peak-to-trough difference), and the acrophase , the peak time location in the 24-h scale). Chronopharmacology became recognized as a scientific domain of investigation only in the early 1970s. For conventionally trained pharmacologists, it was not clear that predictable temporal variations of effects and disposition of agents (e.g. medications, hormones, and toxic substances) are governed by endogenous biological rhythms rather than by changes of external factors. On the 24-h scale (as well as on the yearly scale) there are peaks and troughs of physiological variables that are not randomly distributed; their respective locations correspond to a temporal organization controlled by a set of pacemakers (so-called biological clocks) became recognized as a scientific domain of investigation only in the early 1970s.

ABSORBED BY EVERYDAY LIFE – STUDENTS’ EXPERIENCE OF THE CHANGING GRAMMAR OF SCHOOLING DURING THE CORONAVIRUS PANDEMIC

This paper reports the findings of the study of selected elements of grammar of schooling (temporal and spatial organization, learning interactions). The study presented in this article focuses on the experiences of 64 1st year pedagogy students’ who had learned in the coronavirus pandemic. The data were collected through questionnaire with open-ended questions about the changes students experienced due to the coronavirus pandemic in areas such as the organisation of space, the organisation of time, learning interactions, forms of work, as well as the expected consequences of the changes they are currently witnessing and the anticipated ‘return to normality’. The article presents the findings related to changes in three elements of the grammar of schooling: (1) spatial organization; (2) temporal organization; and (3) educational interactions. The results of the study indicate that students had to reorganize their space-time due to receiving the educational process from home. Students feel swallowed up by everyday life – the educational process has become one of many routine daily activities. They experience a changein privacy boundaries, which has consequences for other family members as well. Students’ relationships with teacher educators are still formal and centered around the content being taught. Relationships with peers have weakened considerably.

CHARACTERISTICS OF EQUILIBRIUM FUNCTION AND THE SENSORY ORGANIZATION OF POSTURAL BALANCE IN WOMEN 85-95 YEARS OLD

Цель работы - установить возрастные особенности показателей эффективности функции равновесия и сенсорной организации постурального баланса у женщин 85-95 лет. Были обследованы 68 женщин 85-95 лет (средний возраст - 89,3±3 года), которых разделили на две возрастные группы: 1-я - 37 женщин 85-89 лет (средний возраст - 86,9±1,6 года); 2-я - 31 женщина 90-95 лет (средний возраст - 92,1±1,4 года). Для оценки компонентов постурального баланса использовали компьютерный динамический постурографический (стабилометрический) комплекс «Smart Equitest Balance Manager». Проводили Sensory Organization Test (SOT). Сравнительная оценка показателей Equilibrium Score во всех функциональных пробах SOT, включая показатель Com posite of all Equilibrium Scores, не выявила статистически значимых различий между группами обследованных женщин. Сенсорный анализ также не выявил возрастных изменений соматосенсорной, зрительной и вестибулярной информации в контроле над балансом. При этом показатель сенсорного предпочтения (Ratio for Sensory Analysis-Patient Preference) был выше у женщин 90-95 лет (p=0,007). У женщин после 89 лет не наблюдали возрастных изменений сенсорной организации постурального контроля, эффективности подержания статического и статодинамического баланса, включая снижение общей производительности баланса, а также адаптационных возможностей их функции равновесия. При этом у женщин-долгожителей сохраняется эффективность процесса сенсорной интеграции для поддержания постурального баланса и чувства пространственной ориентации, что можно рассматривать как предиктор активного долголетия. Кроме этого, у женщин-долгожителей сохраняется способность пространственной и временной организации контроля постурального равновесия, а также степени и порядка набора задействованных мышц для снижения дисбаланса. Полученные результаты позволили обозначить параметры SOT, которые можно учитывать при прогнозировании постуральных изменений и продолжительности жизни у женщин в старческом возрасте. The purpose of this work is to establish the age-related indicators’ characteristics of the effectiveness of the balance function and the postural balance sensory organization in women 85-95 years old. We examined 68 women aged 85-95 years [mean age (M±SD) 89,3±3 years]. The first age group included 37 women whose calendar age ranged from 85 to 89 years (mean age 86,9±1,6 years). The second age group included 31 women of 90-95 years (mean age: 92,1±1,4). To assess the components of the postural balance, a computer-based dynamic posturographic complex «Smart Equitest Balance Manager» was used. The Sensory Organization Test (SOT) was performed. Comparative assessment of the Equilibrium Score indicators in all SOT functional tests, including the Composite of all equilibrium scores, did not reveal statistically significant differences between the examined groups of women. The sensory analysis did not reveal age-related changes in somatosensory, visual and vestibular information in the control over balance, either. At the same time, the indicator of sensory preference (Ratio for sensory analysis-patient Preference) was higher in women 90-95 years old (p=0,007). In women after 89 years of age, there are no age-related changes in the sensory organization of postural control or the effectiveness of maintaining static and static-dynamic balance. No decrease in overall balance performance, as well as the adaptive capabilities of their balance function, was noticed. At the same time, long-lived women retain the effectiveness of the sensory integration process to maintain postural balance and a sense of spatial orientation, which can be considered a predictor of active longevity. In addition, centenarians retain the ability of spatial and temporal organization of postural equilibrium control, as well as the degree and order of the muscles involved to reduce the imbalance recruitment. The results obtained made it possible to designate SOT parameters that can be taken into account when predicting postural changes and life expectancy in women in old age.

Visuomotor adaptation modulates the clustering of sleep spindles into trains

Sleep spindles are thought to promote memory consolidation. Recently, we have shown that visuomotor adaptation (VMA) learning increases the density of spindles and promotes the coupling between spindles and slow oscillations, locally, with the level of spindle-SO synchrony predicting overnight memory retention. Yet, growing evidence suggests that the rhythmicity in spindle occurrence may also influence the stabilization of declarative and procedural memories. Here, we examined if VMA learning promotes the temporal organization of sleep spindles into trains. We found that VMA increased the proportion of spindles and spindle-SO couplings in trains. In agreement with our previous work, this modulation was observed over the contralateral hemisphere to the trained hand, and predicted overnight memory retention. Interestingly, spindles grouped in a cluster showed greater amplitude and duration than isolated spindles. The fact that these features increased as a function of train length, provides evidence supporting a biological advantage of this temporal arrangement. Our work opens the possibility that the periodicity of NREM oscillations may be relevant in the stabilization of procedural memories.