Condition of hard tissues of teeth and oral fluid in athletes-swimmers

Objective: to determine the state of dental hard tissues and saliva parameters changing in competitive swimmers, before and after a 2­hour training session in the chlorinated water swimming pool.Materials and methods: saliva parameters of competitive swimmers trained in the sport club “Grifon”, city of St. Petersburg, Russia (n = 21), age of participants 18.1 ± 3.5 years, qualifications (1 category­Master of Sports) and track and field athletes of the sports schools “Nevsky district” and “Orlyonok”, city of St. Petersburg, Russia (n = 18), age of participants 18.80 ± 4.54 years, qualifications (1 category — Master of Sports), have been analyzed by various tests include a study of calcium (Ca), phosphorus (P), fluorine (F) levels, and pH before and after training sessions. All athletes in the experimental and control groups have passed an examination by dentist, including: examination of the oral cavity with the determination of the KPU index (the sum of carious, filled and removed permanent teeth in the subject), examination of the most common places of occurrence of dental enamel erosion (medical binoculars) and filling out specially designed questionnaires.Results: there was a tendency to decrease of the average saliva pH in competitive swimmers’ group after a training session, varying from 6.9 ± 0.1 (before training) to 6.5 ± 0.1 (after training) (p > 0.05). In track and field athletes, saliva pH did not change significantly (7.1 ± 0.2 before training and 7.0 ± 0.1 after training) (p < 0.05). The competitive swimmers showed a statistically significant increase in Calcium (Ca) levels (1.25 ± 0.15 mmol/L before exercise and 1.56 ± 0.11 mmol/L after exercise) and Fluorine (F) (0.0010 ± 0.0003 mmol / L before exercise and 0.0090 ± 0.0004 mmol / L after training session) in saliva. The Phosphorus (P) level in saliva was significantly reduced after the training session (from 6.09 ± 0.39 to 3.89 ± 0.46 mmol / L) (p > 0.05). In track and field athletes, there were no significant changes in Ca, F and P levels before and after a training session. As a result of the dentist’s examination, competitive swimmers were found to have 3 athletes (14.3 %) with lesions of the teeth enamel, corresponding to dental erosion and caused by localized demineralization. In the control group of athletes, no such pathologies were revealed.Conclusion: discovered saliva parameters changing in competitive swimmers (decrease in free salivation, pH level, and increase in the level of Ca and F in saliva) can contribute to the demineralization of tooth enamel. Timely and controlled use of fluorides (as part of mouth rinses, application gels, fluoride varnishes), regular preventive dental examinations, in order to prevent the loss of mineral composition of the teeth when swimming in chlorinated pools, will minimize the risk of staining and dental enamel erosions

EFFECT OF FULLERENES С60 ON THERMOELECTRIC PROPERTIES OF LEAD TELLURIDE

This paper presents the results of the study of the effect of fullerene C60 on thermoelectric properties PbTe.Работа выполнена при поддержке РФФИ (проект № 19-48-360010)

РЕКОМЕНДАЦИИ ПО ПРОВЕДЕНИЮ ИНФУЗИОННО-ТРАНСФУЗИОННОЙ ТЕРАПИИ У ДЕТЕЙ ВО ВРЕМЯ ХИРУРГИЧЕСКИХ ОПЕРАЦИЙ

Recommendations on peri-operative infusion-transfusion therapy in children have been developed by the members of Association of Children Anesthesiologists and Emergency Physicians of Russia, possessing significant experience of anaesthesiologic and intensive care provided to children. These recommendations are aimed to provide clear instructions on compilation of peri-operative infusion program in order to reduce the risk of complications related to this in children of various age groups, to enhance efficiency and safety of anaesthesiologic support in general. Recommendations do not include some specific issues of infusion therapy in specialized medical fields.Рекомендации по интраоперационной инфузионно-трансфузионной терапии у детей разработаны членами Ассоциации детских анестезиологов-реаниматологов России, имеющих большой опыт оказания анестезиолого-реаниматологической помощи детям. Целью данных рекомендаций является предоставление четких правил по составлению программы интраоперационной инфузии для уменьшения риска осложнений, связанных с ее проведением у детей разных возрастных групп, повышения эффективности и безопасности анестезиологического обеспечения в целом. Рекомендации не рассматривают частные вопросы проведения инфузионной терапии в специализированных областях медицины

Spatial Variability of Snow Water Equivalent – The Case Study from the Research Site in Khibiny Mountains, Russia

The aim of the investigation was assessment of spatial variability of the characteristics of snowpack, including the snow water equivalent (SWE) as the main hydrological characteristic of a seasonal snow cover. The study was performed in Khibiny Mountains (Russia), where snow density and snow cover stratigraphy were documented with the help of the SnowMicropen measurements, allowing to determine the exact position of the snow layers’ boundaries with accuracy of 0.1 cm. The study site was located at the geomorphologically and topographically uniform area with uniform vegetation cover. The measurement was conducted at maximum seasonal SWE on 27 March 2016. Twenty vertical profiles were measured along the 10 m long transect. Vertical resolution depended on the thickness of individual layers and was not less than 10 cm. The spatial variation of the measured snowpack characteristics was substantial even within such a homogeneous landscape. Bulk snow density variability was similar to the variability in snow height. The total variation of the snowpack SWE values along the transect was about 20%, which is more than the variability in snow height or snow density, and should be taken into account in analysis of the results of normally performed in operational hydrology snow course SWE estimations by snow tubes

THE EXPERIENCE OF THE COMPLEX ASSESSMENT OF THE IMPACT OF THE LENGTH OF AGRICULTURAL USE ON PROPERTIES AND REGIMES OF AGROCHERNOZEMS OF STONY STEPPE

The comparative study of impact of long term agricultural use (for 20, 60, and 120 years) on migratory-micellar (typical) chernozems of Stony Steppe (Voronezh oblast, Russia), was conducted. The following properties were investigated: morphology, humus state, structure, water and physical properties, and water and temperature regimes. It is revealed that agro-layers of chernozems are sustainable in time. Their residual specificities are preserved even under long-term (130 years) layland. During the first 10-20 years of agricultural use the decrease of humus content is revealed: the decrease of the humus content including the labile humus matter, and also the decrease of organic carbon content. Hereafter, there occurs the stabilization of their humus state, though on the lower layer, due to relative equilibrium with the processes of organic matter new formation. In the first years of the agricultural use there is observed the insignificant increase of the bulk density, deterioration of the structure and the decrease of the porosity, water capacity and plant available water content. Further the physical state of these layers of chernozems is preserved on the optimal level. The heath provision of the plowland is higher than that under the natural vegetation due to the heating to the higher temperatures which causes the physical desiccation and accumulation of carbonates in the surface layers. The water regime of chernozems as mixed-aged plowlands, and long-termed layland of Stony Steppe may be determined as periodically percolative regime with additional ground moistening. The main reason of that may be the presence of water-accumulating layer (200-300 cm) above the aquiclude, which is composed of clays lying at the depth of 300 cm

Bicyclo[4.2.0]octa-1,3,5-trien-3-yl-dimethyl((E)-styryl)-silane

Bicyclo[4.2.0]octa-1,3,5-trien-3-yl-dimethyl-((E)-styryl)-silane was synthesized via three stage synthesis starting from benzocyclobutene and (2-bromo-vinyl)-benzene. The structure of the product was determined using 1H- and 13C-NMR and HRMS