Disturbance of meromixis in saline Lake Shira (Siberia, Russia): possible reasons and ecosystem response

Saline Lake Shira (Southern Siberia, Russia) was meromictic through the observation period 2002-2015. During the under-ice periods of 2015 and 2016, complete mixing of the water column was recorded for the first time, and hydrogen sulphide temporarily disappeared from the water column of the lake; i.e. in those years the lake turned to holomixis. In the summer of 2015, a sharp increase in chlorophyll a, organic carbon, zooplankton, and phytoflagellates was observed in the lake, which was probably due to the release of nutrients from the monimolimnion. Purple sulfur bacteria completely disappeared from the lake after the first mixing in 2015, and did not reappear despite the restoration of meromixis in 2017. Thus, it was demonstrated that purple sulfur bacteria are sensitive to the weakening of the stratification of Lake Shira. Based on the data of the seasonal monitoring of temperature and salinity profiles over the period 2002-2017, it was presumed that the main cause of deep mixing in 2015 was the weakening of the salinity gradient due to strong wind impact and early ice retreat in the spring of 2014. In addition, it was shown that in previous years a significant contribution to the maintenance of meromixis was made by an additional influx of fresh water, which caused a rise in the lake level in the period 2002-2007. Thus, we identified a relationship between the stratification regime of the lake and the change in its level, which provides valuable information both for the forecast of water quality and for reconstruction of the Holocene climate humidity in this region of Southern Siberia from the sediment cores of Lake Shira

The first combined russian experience of using perampanel in children and adolescents with epilepsy in everyday clinical practice

Background. Real world data help to provide more information on the effects and tolerability of therapy. However, data on the use of perampanel in Russian population of children remain limited. aim. To conduct a retrospective analysis of perampanel efficacy and tolerability in children and adolescents with epilepsy in real clinical practice. Materials and methods. A total of 106 children aged 4–18 years receiving perampanel as part of combination therapy for epilepsy were observed at 18 centers. Seizure frequency at 1–3, after 6 and 12 months of treatment, presence and type of adverse events (AEs) were analyzed. The main assessed efficacy parameters were seizure control, significant (≥50 %) decrease in seizure frequency. All other outcomes (<50 % decrease, no change or increased seizure frequency) were considered to be no effect. The assessed safety parameters were the percentage of patients with or without AEs and the percentage of perampanel withdrawals due to AEs. results. We defined 3 age groups for comparison: children 4–6, 7–11 and 12–17 years old. Perampanel efficacy was 69 % (seizure control – 23.6 %, ≥50 % decrease in seizure frequency – 45.3 %). The mean duration of the effect was 7.3 ± 4.1 months. No significant difference in efficacy between age groups was found. However, some greater efficacy of perampanel was noted in adolescents: absence of effect in the form of remission or significant decrease in seizures frequency was noted only in 25.5 %, with 40 % in children 4–11 years old. Among those with inefficacy, 3.8 % reported seizure aggravation. AEs occurred in only 23 % of patients, with the least frequent occurrence in adolescents (11.8 %) and the most frequent in children aged 7–11 years (40 %). The most frequent AEs was sluggishness and/or drowsiness. Discontinuation of perampanel due to AEs was required in 7.6 %. Conclusion. Perampanel has demonstrated high efficacy and good tolerability in real clinical practice among children from 4 years of age and adolescents with partial (focal) and secondary generalized seizures. The AEs that developed were not serious and very rarely led to withdrawal of the therapy. The results are comparable to those of phase III studies and previous real-world data. The usage of perampanel in children with primary generalized seizures should be further investigated. © 2022 ABV-Press Publishing House. All rights reserved.EisaiО.А. Рахманина / O.A. Rakhmanina: https://orcid.org/0000-0001-9218-2531 И.В. Волков / I.V. Volkov: https://orcid.org/0000-0002-7816-7535 О.К. Волкова / O.K. Volkova: https://orcid.org/0000-0003-3314-3895 Ю.А. Александров / Yu.A. Aleksandrov: https://orcid.org/0000-0003-3887-5219 М.В. Бархатов / M.V. Barkhatov: https://orcid.org/0000-0002-6372-4677 И.С. Бахтин / I.S. Bakhtin: https://orcid.org/0000-0003-3600-687X Г.М. Бережная / G.M. Berezhnaya: https://orcid.org/0000-0003-3917-422X А.Ю. Карась / A.Yu. Karas: https://orcid.org/0000-0001-9089-9627 Д.В. Морозов / D.V. Morozov: https://orcid.org/0000-0003-4389-9143 И.С. Бахтин / I.S. Bakhtin: https://orcid.org/0000-0003-3600-687X Т.Р. Томенко / T.R. Tomenko: https://orcid.org/0000-0002-0652-1996 Ж.М. Цоцонава / Zh.M. Tsotsonava: https://orcid.org/0000-0003-3275-5099 Конфликт интересов и финансирование. Публикация подготовлена при финансовой поддержке компании «Эйсай». Авторы несут полную ответственность за содержание статьи и редакционные решения. Conflict of interest and funding. This publication was funded by Eisai. The authors are fully responsible for the content of the article and editorial decisions

Retracted: Small business taxation in European countries: crucial points, specific features and potential adaptation of advantageous options

This article was withdrawn and retracted by the Journal of Fundamental and Applied Sciences and has been removed from AJOL at the request of the journal Editor in Chief and the organisers of the conference at which the articles were presented (www.iccmit.net). Please address any queries to [email protected]

Disturbance of meromixis in saline Lake Shira (Siberia, Russia): possible reasons and ecosystem response

Saline Lake Shira (Southern Siberia, Russia) was meromictic through the observation period 2002-2015. During the under-ice periods of 2015 and 2016, complete mixing of the water column was recorded for the first time, and hydrogen sulphide temporarily disappeared from the water column of the lake; i.e. in those years the lake turned to holomixis. In the summer of 2015, a sharp increase in chlorophyll a, organic carbon, zooplankton, and phytoflagellates was observed in the lake, which was probably due to the release of nutrients from the monimolimnion. Purple sulfur bacteria completely disappeared from the lake after the first mixing in 2015, and did not reappear despite the restoration of meromixis in 2017. Thus, it was demonstrated that purple sulfur bacteria are sensitive to the weakening of the stratification of Lake Shira. Based on the data of the seasonal monitoring of temperature and salinity profiles over the period 2002-2017, it was presumed that the main cause of deep mixing in 2015 was the weakening of the salinity gradient due to strong wind impact and early ice retreat in the spring of 2014. In addition, it was shown that in previous years a significant contribution to the maintenance of meromixis was made by an additional influx of fresh water, which caused a rise in the lake level in the period 2002-2007. Thus, we identified a relationship between the stratification regime of the lake and the change in its level, which provides valuable information both for the forecast of water quality and for reconstruction of the Holocene climate humidity in this region of Southern Siberia from the sediment cores of Lake Shira

Measuring Alloxanthin as a Proxy Approach in a Study of Trophic Relationships between Zooplankton and Cryptophyte Algae in Lake Shira

Криптофитовые водоросли признаны важным трофическим звеном многих водных экосистем, однако остаются недостаточно изученными в плане трофических взаимодействий с другими компонентами экосистем. Они являются более качественной пищей, чем большинство других водорослей, и поэтому могут быть подвержены селективному выеданию со стороны зоопланктона. Следовательно, прямые измерения динамики их концентрации в озерах могут давать очень сильно заниженные показатели продукции. Одним из способов оценки потребления криптофитовых водорослей зоопланктоном служит определение содержания в нем специфического для криптомонад каротиноида аллоксантина. В работе исследовалось содержание аллоксантина в осадочных илах, седиментационных ловушках и зоопланктоне озера Шира с помощью высокоэффективной жидкостной хроматографии. Была показана значимая корреляция между количеством некоторых видов зоопланктона, способных потреблять криптофитовые водоросли, и потоком осаждаемого аллоксантина, зафиксированным в седиментационных ловушках. Результат анализа проб зоопланктона (наибольший вклад в биомассу которого обеспечивал веслоногий рачок Arctodiaptomus salinus (Daday, 1885)) на содержание каротиноидов в течение весенне-летнего сезона показал наличие аллоксантина в количестве до 80 мкг/г, снижающееся к концу сезона, что коррелировало с биомассой криптофитовых водорослей в озере. Каротиноиды, ассоциированные с другими группами водорослей, наблюдались в значительно меньшем количестве. Это демонстрирует высокий уровень селективного потребления веслоногим рачком A.salinus криптофитовых водорослей и может служить подтверждением тесной трофической связи между нимиCryptophyte algae are an important trophic link in many aquatic ecosystems, but they remain insufficiently studied in terms of trophic interactions with other components of ecosystems. They are better quality food than most other algae and, therefore, can be subject to selective grazing by zooplankton; thus, direct measurements of the dynamics of their concentration in lakes may give very low productivity indicators. One way to assess the consumption of cryptophyte algae by zooplankton is to determine the content of alloxanthin, a carotenoid specific for cryptophyte algae, in zooplankton. The present study investigated the alloxanthin content of sedimentary silts, sedimentation traps, and zooplankton of Lake Shira using high performance liquid chromatography. A significant correlation was found between the abundance of some zooplankton species capable of consuming cryptophyte algae and the flux of precipitated alloxanthin recorded in sedimentation traps. Analysis of zooplankton samples (the largest contribution to the biomass of which was made by the copepod Arctodiaptomus salinus (Daday, 1885)) for the content of carotenoids during the spring-summer season showed the presence of alloxanthin amounts reaching 80 μg/g, which decreased by the end of the season, and that correlated with the biomass of cryptophyte algae in the lake. Carotenoids associated with other groups of algae were observed in considerably smaller amounts. Thus, the copepod A. salinus exhibits high selective consumption of cryptophyte algae, which may serve as a confirmation of a close trophic relationship between the