Arctic polar vortex dynamics during winters 2014/2015 and 2020/2021

The dynamic barrier of the polar vortex contributes to lowering the temperature inside the vortex in the lower stratosphere and prevents the penetration of air masses into the vortex. The presence of a dynamic barrier during winter is one of the criteria determining the possibility of ozone depletion from late winter to spring. We considered the dynamics of the Arctic polar vortex in the winters of 2014/2015 and 2020/2021 at the 50, 30 and 10 hPa levels by the vortex delineation method using the geopotential. In early January 2015 and 2021, sudden stratospheric warmings were recorded as a result of the splitting (4 January 2015) and the significant displacement (5 January 2021) of the polar vortex. In both cases, the weakening of the dynamic barrier of the polar vortex was observed. The polar vortex is characterized by the presence of a dynamic barrier, when the wind speed along the entire edge of the vortex is more than 20, 24 and 30 m/s at the 50, 30 and 10 hPa levels, respectively. A decrease in the average wind speed along the vortex edge below 30, 36 and 45 m/s, at the 50, 30 and 10 hPa levels, respectively, usually indicates a local decrease in the wind speed below 20, 24 and 30 m/s at these levels, i.e., indirectly indicates a weakening of the dynamic barrier.The dynamic barrier of the polar vortex contributes to lowering the temperature inside the vortex in the lower stratosphere and prevents the penetration of air masses into the vortex. The presence of a dynamic barrier during winter is one of the criteria determining the possibility of ozone depletion from late winter to spring. We considered the dynamics of the Arctic polar vortex in the winters of 2014/2015 and 2020/2021 at the 50, 30 and 10 hPa levels by the vortex delineation method using the geopotential. In early January 2015 and 2021, sudden stratospheric warmings were recorded as a result of the splitting (4 January 2015) and the significant displacement (5 January 2021) of the polar vortex. In both cases, the weakening of the dynamic barrier of the polar vortex was observed. The polar vortex is characterized by the presence of a dynamic barrier, when the wind speed along the entire edge of the vortex is more than 20, 24 and 30 m/s at the 50, 30 and 10 hPa levels, respectively. A decrease in the average wind speed along the vortex edge below 30, 36 and 45 m/s, at the 50, 30 and 10 hPa levels, respectively, usually indicates a local decrease in the wind speed below 20, 24 and 30 m/s at these levels, i.e., indirectly indicates a weakening of the dynamic barrier

ОПЫТ ПРИМЕНЕНИЯ ГАЗОВОЙ ХРОМАТОМАСС-СПЕКТРОМЕТРИИ В СОЧЕТАНИИ С ТВЕРДОФАЗНОЙ МИКРОЭКСТРАКЦИЕЙ ДЛЯ ИССЛЕДОВАНИЯ СОСТАВА ЛЕТУЧИХ ОРГАНИЧЕСКИХ СОЕДИНЕНИЙ В МАТРИЦАХ С ВЫСОКИМ СОДЕРЖАНИЕМ ЖИРОВ

Current article presents a methodological approach for a comparative study of the composition of volatile organic compounds (VOCs) in a natural product and a nature-identical flavoring substance. The identification of VOCs was performed by gas chromatography-mass spectrometry without reference compounds. The identification was made based on coincidence of the experimental and reference mass spectra and linear retention indices. During the first step, the closest match factor substance was selected based on the library search. During the second step, the result was verified by the means of experimental and reference retention indices data proximity.  The reference retention indices were selected considering the identity of the experimental conditions (chromatographic stationary phase, temperature programming mode). The impossibility of identification of aroma components in acetonitrile extract of fragrance was shown due to the overlapping of their peaks with peaks of di- and tri- glycerides of fatty acids.  The extraction and concentration of VOCs from vapor were carried out using the head space solid-phase microextraction. The fragrance content investigation revealed 39 volatile organic compounds including propylene glycol and triacetin as the markers of synthetic fragrances. In natural cocoa butter, also 39 volatile organic compounds were identified. All of them were common for the fermented cocoa beans. Pyrazines derivatives, characteristic of cocoa aroma, were presented with the following 7 components: 2,3-dimethylpyrazine; 2,5-dimethylpyrazine; ethylpyrazine; 2-methyl-6-ethylpyrazine; 2,3,5-trimethylpyrazine, 2,5-dimethyl-3-ethylpyrazine; tetramethylpyrazine. In quantitative terms, the isomeric 2,3-butandiols predominate in the head space of natural cocoa butter accounting for 37 percent of total VOC content. The analytical technique used allows investigation of multicomponent objects including the heterogeneous ones.Key words: gas chromatography-mass spectrometry, head space solid-phase microextraction, mass spectra, retention indices, fragrance  DOI: http://dx.doi.org/10.15826/analitika.2020.24.1.003E. Savelieva E. Kessenikh and L. Gustyleva  Research Institute of Hygiene, Occupational Pathology and Human Ecology,g/p Kiz’molovskii, Vsevolozhskii raion, Leningradskaia oblast’, 188663,Russian FederationВ работе представлен методический подход для сравнительного исследования компонентного состава летучих органических соединений (ЛОС) в матрицах, основу которых составляют жирные кислоты: натуральном продукте и ароматизаторе, идентичном натуральному. Идентификацию летучих органических соединений проводили методом газовой хроматомасс-спектрометрии без использования образцов сравнения на основании масс-спектров электронной ионизации и линейных индексов удерживания. На первом этапе методом компьютерного библиотечного поиска устанавливали соединение с максимальным фактором совпадения по масс-спектру. На втором этапе проверяли результат идентификации путем сопоставления экспериментальных и справочных величин индексов удерживания. Справочные величины индексов удерживания подбирали с учетом идентичности экспериментальных условий (неподвижная фаза колонки, режим программирования температуры). Показано, что в ацетонитрильном экстракте ароматизатора идентифицировать ароматобразующие соединения не представляется возможными ввиду их перекрывания пиками ди- три-глицеридов жирных кислот. Улавливание из паровой фазы и концентрирование летучих соединений проводили методом твердофазной микроэкстракции. В составе ароматизатора идентифицировано 39 летучих компонентов, в том числе растворители пропиленгликоль и триацетин, присутствие которых является главным отличием искусственного ароматизатора от натурального продукта. В натуральном масле какао также идентифицировано 39 летучих веществ. Все они являются характерными компонентами для ферментированных какао-бобов. Группа алкилпиразинов, характерных для аромата какао, в натуральном продукте представлена семью компонентами: 2,3-диметилпиразин, 2,5-диметилпиразин, этилпиразин, 2-метил-6-этилпиразин, 2,3,5-триметилпиразин; 2,5-диметил-3- этилпиразин; тетраметилпиразин. В количественном отношении в натуральном масле какао преобладают изомерные 2,3-бутандиолы, суммарно составляющие 37 % от общего содержания ЛОС в паровой фазе. Использованная техника анализа может быть распространена на другие объекты сложного, в том числе и гетерогенного, состава. Ключевые слова: газовая хроматомасс-спектрометрия, твердофазная микроэкстракция из газовой фазы, масс-спектры, индексы удерживания, ароматизаторыDOI: http://dx.doi.org/10.15826/analitika.2020.24.1.00

The Method of Light Dose Measurement During Phodinamic Therapy

A new method of light dose monitoring during the photodynamic therapy of abdominal cavity organs was developed. To apply this method specially developed sensors were constructed. For these sensors the temporal and distance dependences of light doses were received and analyzed. It was shown that the light dose from the operating lamp is large enough in laser light field to be taken into account when planning photodynamic therapy. Keywords: PDT, light doses, other source of light in PDT, photodynamic therap

The effect of anthracene derivatives on the state of the extracellular matrix of the periodontal connective tissue and the oral mucosa of old rats

In the experiments on 27 old female rats, the effect of the anthracene derivative preparation on the state of the intercellular matrix of the connective tissue of the periodontal and oral mucosa in intact animals, as well as on the periodontitis model, was studied

The subject of crime: the problem of establishing age limits of criminal responsibility

This article presents the authors’ analysis of the problem of determining the subject of a crime as a legal concept, and defining the legal characteristics of a person who has committed a crime by features that are necessary for criminal responsibility (individual, age, and responsibility

СОВЕРШЕНСТВОВАНИЕ ПРОЦЕДУРЫ ОПРЕДЕЛЕНИЯ БИС(2-ХЛОРЭТИЛ)СУЛЬФИДА В МАТЕРИАЛАХ С ВЫСОКОЙ СОРБЦИОННОЙ АКТИВНОСТЬЮ

A rapid, unified, highly sensitive and selective procedure for bis(2-chloroethyl)sulfide (sulfur mustard, SM) determination in matrices with high sorption activity using gas chromatography-tandem mass-spectrometry (GC-MS/MS) was developed. Ceramic tile, concrete, various types of bricks and polymers were studied as objects of the analysis. The parameters for the GC-MS/MS determination of SM were optimized. The efficiency of five solvents (diethyl ether, 2-chloropropane, acetonitrile, hexane, and acetone) for the extraction of SM from the various matrices was studied. 2-chloropropane was the extraction solvent of choice. The developed procedure is based on the extraction of SM from the matrix and the concentration of the extract under the stream of nitrogen to 0.2 mL followed by GC-MS/MS analysis. The LODs for SM in all investigated matrices were 0.7-0.9 ng/g (0.007-0.009 MPC). The long-term stability of SM in various materials was studied. It was shown that in brick, concrete and ceramic samples the residual amount of SM after five months of storage at 4°C was below the LOD of the method, while in polymer samples under the same storage condition the amount of SM has not changed significantly. The developed procedure has been applied to the analysis of samples from the former chemical weapons destruction facility.Key words: bis(2-chloroethyl)sulfide, sulfur mustard, construction materials, gas chromatography, tandem mass-spectrometryDOI: http://dx.doi.org/10.15826/analitika.2021.25.2.004 M.D. Shachneva, N.L. Koryagina, E.I. Savelieva Research Institute of Hygiene, Occupational Pathology and Human EcologyFederal State Unitary Enterprise, Federal Medical Biological Agency,g/p Kuz’molovsky, Vsevolozhsky District, Leningrad Region, 188663, Russian FederationРазработана унифицированная высокочувствительная высокоселективная и экспрессная процедура определения бис(2-хлорэтил)сульфида (сернистого иприта) в образцах с высокой сорбционной активностью методом газовой хроматографии с тандемным масс-селективным детектированием (ГХ-МС/МС). Процедура основана на экстракции бис(2-хлорэтил)сульфида из матрицы и концентрировании экстракта в токе азота до 0.2 мл с последующим анализом методом ГХ-МС/МС. В качестве объектов анализа исследованы керамическая плитка, бетон, различные виды кирпича и полимеров. Предел определения иприта в разных матрицах составил 0.7-0.9 нг/г (0.007-0.009 ПДК). Изучена эффективность пяти экстрагентов (диэтилового эфира, 2-хлорпропана, ацетонитрила, гексана и ацетона) для извлечения аналита из матриц различной природы. Показано, что для извлечения бис(2-хлорэтил)сульфида из впитывающих материалов оптимальным экстрагентом является 2-хлорпропан. Исследована стабильность бис(2-хлорэтил)сульфида в составе впитывающих материалов в процессе длительного хранения. Показано, что в образцах на основе бетона после пяти месяцев хранения при температуре 4 °С остаточное содержание бис(2-хлорэтил)сульфида ниже предела обнаружения методики, в то время как в полимерных материалах в этих же условиях хранения содержание бис(2-хлорэтил)сульфида практически не менялось. Проведена апробация методики на образцах строительных материалов, отобранных при мониторинге бывшего объекта по уничтожению химического оружия на этапе конверсии.Ключевые слова: бис(2-хлорэтил)сульфид, сернистый иприт, строительные материалы, газовая хроматография, тандемное масс-селективное детектированиеDOI: http://dx.doi.org/10.15826/analitika.2021.25.2.00

The role of polymorphic variants of arginase genes (<i>ARG1, ARG2</i>) involved in beta-2-agonist metabolism in the development and course of asthma

Asthma is a common severe disease of the respiratory tract, it leads to a significant impairment in the quality of a patient’s life unless effectively treated. Uncontrolled asthma symptoms are a cause of disease progression and development, they lead to an increase in the patient’s disability. The sensitivity to asthma therapy largely depends on the interaction of genetic and epigenetic factors, which account for about 50–60 % of variability of therapeutic response. Beta-2-agonists are some of the major class of bronchodilators used for asthma management. According to published data, allelic variants of the arginase ARG1 and ARG2 genes are associated with a risk of asthma development, spirometry measures and efficacy of bronchodilator therapy. High arginase activity results in a low level of plasma L-arginine and in a decrease in nitric oxide, and, as a result, in an increase in airway inflammation and remodeling. Arginase genetic polymorphisms (rs2781667 of the ARG1 gene, rs17249437, rs3742879, rs7140310 of the ARG2 gene) were studied in 236 children with asthma and 194 unrelated healthy individuals of Russian, Tatar and Bashkir ethnicity from the Republic of Bashkortostan. Association analysis of the studied polymorphisms with asthma development and course, the sensitivity to therapy in patients was carried out. It was found that the rs2781667*C allele of the ARG1 gene is a marker of an increased risk of asthma in Tatars. In Russians, the association of rs17249437*TT and rs3742879*GG genotypes of the ARG2 gene with a decrease in spirometry measures (FEV1, MEF25) was established. In Russians and Tatars receiving glucocorticoid monotherapy or combination therapy, the association of the rs17249437*T allele and rs17249437*TT genotype of the ARG2 gene with a partially controlled and uncontrolled course of asthma was shown

Postglacial vegetation and climate change in the Lake Onega region of eastern Fennoscandia derived from a radiocarbon-dated pollen record

With its numerous environmental archives stored in lake and peat sediments and relatively low human pressure, the Lake Onega region in eastern Fennoscandia is regarded as a particularly promising area for studying past changes in vegetation and climate since the Lateglacial period. The 885-cm-long sediment core RZ19 (62°27′53″N, 34°26′4″E) was collected from Razlomnoe Peat on the northern shore of Lake Onega in 2019, radiocarbon-dated and analysed for pollen and cryptogam spores. The age-depth model suggests continuous sedimentation since ca. 11,800 a BP (all ages given in years (a) or kiloyears (ka) before present (BP) with BP referring to 1950 CE). The results of pollen analysis and pollen-based biome reconstruction show rapid afforestation of the area in the Early Holocene, although the scores of the tundra biome remain relatively high prior to ca. 11,450 a BP, suggesting that the vegetation was likely more open than today. Between 8300 and 8000 a BP, Betula sect. Albae shows a marked increase in pollen percentage, while Pinus sylvestris experiences a marked decrease. These changes coinciding with the 8.2 ka BP cooling event indicate less favourable conditions for Scots pine while being beneficial for fast-growing birch. The transition from the Early to Middle Holocene (i.e. from Greenlandian to Northgrippian) is marked by an increase in pollen productivity, spread of Picea and further afforestation of the area. The decrease in arboreal and Picea pollen percentages and the abrupt increase in landscape openness after ca. 4000 a BP mark the onset of the Late Holocene (i.e. Northgrippian-Meghalayan transition) and likely reflect the combined effect of insolation-induced temperature decrease and associated paludification and forest retreat rather than a decrease in atmospheric precipitation and/or spread of Late Neolithic agriculture