Scientific justification of the perforation methods for Famennian deposits in the southeast of the Perm Region based on geomechanical modelling

The article presents the results of analysing geological structure of the Famennian deposits (Devonian) in the Perm Region. Numerical modelling of the distribution of inhomogeneous stress field near the well was performed for the two considered types of perforation. With regard for the geometry of the forming perforation channels, numerical finite element models of near-wellbore zones were created considering slotted and cumulative perforation. It is ascertained that in the course of slotted perforation, conditions are created for a significant restoration of effective stresses and, as a result, restoration of reservoir rock permeability. Stress recovery area lies near the well within a radius equal to the length of the slots, and depends on the drawdown, with its increase, the area decreases. From the assessment of failure areas, it was found that in case of slotted perforation, the reservoir in near-wellbore zone remains stable, and failure zones can appear only at drawdowns of 10 MPa and more. The opposite situation was recorded for cumulative perforation; failure zones near the holes appear even at a drawdown of 2 MPa. In general, the analysis of results of numerical simulation of the stress state for two simulated types of perforation suggests that slotted perforation is more efficient than cumulative perforation. At the same time, the final conclusion could be drawn after determining the patterns of changes in permeability of the considered rocks under the influence of changing effective stresses and performing calculations of well flow rates after making the considered types of perforation channels

Accounting of geomechanical layer properties in multi-layer oil field development

Amid the ever-increasing urgency to develop oil fields with complex mining and geological conditions and low-efficiency reservoirs, in the process of structurally complex reservoir exploitation a number of problems arise, which are associated with the impact of layer fractures on filtration processes, significant heterogeneity of the structure, variability of stress-strain states of the rock mass, etc. Hence an important task in production engineering of such fields is a comprehensive accounting of their complex geology. In order to solve such problems, the authors suggest a methodological approach, which provides for a more reliable forecast of changes in reservoir pressure when constructing a geological and hydrodynamic model of a multi-layer field. Another relevant issue in the forecasting of performance parameters is accounting of rock compressibility and its impact on absolute permeability, which is the main factor defining the law of fluid filtration in the productive layer. The paper contains analysis of complex geology of a multi-layer formation at the Alpha field, results of compression test for 178 standard core samples, obtained dependencies between compressibility factor and porosity of each layer. By means of multiple regression, dependencies between permeability and a range of parameters (porosity, density, calcite and dolomite content, compressibility) were obtained, which allowed to take into account the impact of secondary processes on the formation of absolute permeability. At the final stage, efficiency of the proposed methodological approach for construction of a geological and hydrodynamic model of an oil field was assessed. An enhancement in the quality of well-by-well adaptation of main performance parameters, as well as an improvement in predictive ability of the adjusted model, was identified

Фенольные соединения этанольных извлечений Lemna minor L., Lemna trisulca L. и Lemna polyrrhiza L. Schleid. и их иммуномодулирующая активность

The purpose of the study is to determine the composition of the phenolic compounds of ethanol extracts isolated from three species of duckweed: Lemna minor L., Lemna trisulca L. and Lemna polyrrhiza L. (the synonym is Spirodella polyrrhiza Schleid.) and to study its effect on immune system activation.Materials and methods. The objects of the study are: air-dried grass samples of Lemna minor L., Lemna trisuica L. and Lemna polyrrhiza L. collected during their growing season in 2010–2011 in low-flow and stagnant ponds of Kozhevnikovsky and Tomsk districts of Tomsk region. Isolation of polyphenolic complexes (PFC) was carried out by extraction of air-dried raw material with ethyl alcohol. In qualitative and quantitative analysis of the samples studied the method of reversed-phase high-performance liquid chromatography on an Agilent 1100 Series instrument (USA) was used in isocratic mode. In the experiments, 200 male C57BL / 6 and BALB / C mice aged 8–12 weeks were used to determine immunomodulatory activity. Cell proliferation was assessed by a colorimetric method. The absorption of the obtained solutions was measured with a multi-channel spectrophotometer at the wavelength of 540 nm. The determination of antibody-forming cells in the spleen was performed by local hemolysis. The titer of antibodies in serum was evaluated in the hemagglutination reaction. The local hypersensitivity reaction of immediate type was assessed by the author’s modification.Results. For the first time the study of the qualitative composition and quantitative content of PFC of Lemna minor L. (LM) , Lemna trisulca L. (LT) trisulkas, and Lemna polyrrhiza L. (LP) : (4,7 ± 0,4)%, (3,3 ± 0,3)%, (12,8 ± 0,7)% was carried out. The highest content of phenolic acids (10,76%) and the sum of flavonoids, isoflavonoids and coumarins (14,7%) were found in the LP sample. The content of chlorogenic and 3,5-dihydroxybenzoic acids was 2–9 times higher in LP than in other species of duckweed. In LM and LT with concentrations of 5 μg/ml and LP in the range of 0,5–160 μg/ml did not have a toxic effect on antigen presenting cells. When incubated with LT (20 μg/ml), the proliferation of macrophages was reduced by 1,2 times, and when incubated with LM and LT (80 μg/ml), by 1,2 and 1,8 times, respectively. PFC duckweed (LP) did not have a similar effect. LM and LP had a stimulating effect on the production of nitrites in the concentrations of 5 and 20 μg/ml, increasing it by 1,3–1,6 times. Course introduction of LT and LP led to a significant decrease in the number of antibody-forming cells by 1,5 and 2,3 times and a decrease in the local hypersensitivity reaction by 1,9 and 1,5 times, respectively.Цель исследования. Определение состава фенольных соединений этанольных извлечений, выделенных из трех видов ряски: ряски малой (Lemna minor L.), ряски тройчатой (Lemna trisulca L.) и ряски многокорневой (Lemna polyrrhiza L., синоним Spirodella polyrrhiza L.) Schleid.), и изучение его влияния на активацию системы иммунитета.Материал и методы. Объект исследования: воздушно-сухие образцы травы ряски малой (Lemna minor L.), ряски тройчатой (Lemna trisuica L.) и ряски многокорневой (Lemna polyrrhiza L.), собранные в период их вегетации в 2010–2011 гг. в малопроточных и стоячих водоемах Кожевниковского и Томского районов Томской области. Выделение полифенольных комплексов (ПФК) проводили экстракцией воздушно-сухого сырья спиртом этиловым. При качественном и количественном анализе исследуемых образцов применяли метод обращенно-фазовой высокоэффективной жидкостной хроматографии на приборе Agilent 1100 Series (США) в изократическом режиме. В экспериментах для определения иммуномодулирующей активности использовали 200 самцов мышей линий С57ВL/6 и BALB/C в возрасте 8–12 нед. Пролиферацию клеток оценивали колориметрическим методом. Абсорбцию полученных растворов замеряли при помощи многоканального спектрофотометра при длине волны 540 нм. Определение антителообразующих клеток в селезенке проводили методом локального гемолиза. Титр антител в сыворотке крови оценивали в реакции гемагглютинации. Локальную реакцию гиперчувствительности немедленного типа оценивали по методике в авторской модификации.Результаты. Впервые проведено исследование качественного состава и количественного содержания ПФК ряски малой Lemna minor L. (LM), ряски трисульки Lemna trisulca L. (LT) и ряски многокорневой Lemna polyrrhiza L.(LP): (4,7 ± 0,4)%, (3,3 ± 0,3)%, (12,8 ± 0,7)% соответственно. Наибольшее содержание фенолокислот (10,76%) и суммы флавоноидов, изофлавоноидов и кумаринов (14,7%) обнаружено в образце LP. Содержание хлорогеновой и 3,5-дигидроксибензойной кислот в 2–9 раз больше в LP, чем других видах ряски. LM, LT в концентрации 5 мкг/мл и LP в диапазоне 0,5–160 мкг/мл не оказывают токсического действия на антигенпрезентирующие клетки. При инкубации с LT (20 мкг/мл) пролиферация макрофагов снижается в 1,2 раза, а при инкубации с LM и LT (80 мкг/мл) в 1,2 и 1,8 раза соответственно. ПФК ряски многокорневой (LP) не оказывают подобного эффекта. LM и LP оказывают стимулирующее действие на продукцию нитритов в концентрациях 5 и 20 мкг/мл, усиливая ее в 1,3–1,6 раза. Курсовое введение LT и LP приводит к достоверному снижению числа антителобразующих клеток в 1,5 и 2,3 раза и уменьшению величины локальной реакции гиперчувствительности в 1,9 и 1,5 раза соответственно

Physicochemical Characterization and Antioxidant Activity of Humic Acids Isolated from Peat of Various Origins

Although humic acids (HAs) from peat exhibit various therapeutic properties, there is little information available concerning their physicochemical and antioxidant properties. To address this issue, nine different types of peat, including oligotrophic, mesotrophic, and minerotrophic peat samples, were used for isolation of HA fractions by basic (HAb) and pyrophosphate (HAp) extractions. Physical parameters of the HAs were analyzed by UV-Vis, fluorescent, infrared (IR), and electron paramagnetic resonance (EPR) spectroscopy. Average Mr of the fractions ranged from 17.2 to 39.7 kDa, while their humification index (HIX) varied from 0.49 to 1.21. HAp fractions had a higher content of aromatic structures compared to HAb fractions. Moreover, HAp fractions had a significantly higher content of phenolic OH groups (3.6 ± 0.5 mmol/g) versus HAb (3.1 ± 0.5 mmol/g). All HA fractions exhibited antioxidant activity in radical scavenging and electrochemical assays, and their EPR signal had a single line with g = 2.0035, which is consistent with semiquinone type radicals. Furthermore, the HIX was found to be important in determining the number of semiquinone-type free radicals in the HA structures. Overall, these data provide a molecular basis to explain at least part of the beneficial therapeutic properties of peat-derived HAs

UMAOH calcium phosphate coatings designed for drug delivery: vancomycin, 5-fluorouracil, interferon α-2b case

Drug delivery systems based on calcium phosphate (CaP) coatings have been recently recognized as beneficial drug delivery systems in complex cases of bone diseases for admission of drugs in the localized area, simultaneously inducing osteoinduction because of the bioavailable Ca and P ions. However, micro-arc oxidation (MAO) deposition of CaP does not allow for the formation of a coating with sufficient interconnected porosity for drug delivery purposes. Here, we report on the method to deposit CaP-based coatings using a new hybrid ultrasound-assisted MAO (UMAOH) method for deposition of coatings for drug delivery that could carry various types of drugs, such as cytostatic, antibacterial, or immunomodulatory compositions. Application of UMAOH resulted in coatings with an Ra roughness equal to 3.5 mu m, a thickness of 50-55 mu m, and a combination of high values of internal and surface porosity, 39 and 28%, respectively. The coating is represented by the monetite phase that is distributed in the matrix of amorphous CaP. Optimal conditions of coating deposition have been determined and used for drug delivery by impregnation with Vancomycin, 5-Fluorouracil, and Interferon-alpha-2b. Cytotoxicity and antimicrobial activity of the manufactured drug-carrying coatings have been studied using the three different cell lines and methicillin-resistant S. aureus

Quantitative Structure-Activity Relationship, Ontology-Based Model of the Antioxidant and Cell Protective Activity of Peat Humic Acids

Peat humic acids are well known for their wide range of biological effects which can be attributed to the complex chemical structure of naturally occurring humic substances. One of the promising tools is an ontology-based quantitative analysis of the relationship between physical and chemical parameters describing a chemical structure of peat humic acids and their biological activity. This article demonstrates the feasibility of such an approach to estimate the antioxidant and cell protective properties of the peat humic acids. The structural parameters of the peat humic acids were studied by electronic, fluorescence, infrared, 13C-NMR spectroscopy, titrimetric analysis, elemental C,H,N, and O- analysis, and gel chromatography. Antioxidant and antiradical activities were assessed by physicochemical methods of analysis: electronic paramagnetic resonance, cathodic voltammetry, ABTS•+ scavenging, assay of DPPH radical-scavenging activity, assay of superoxide radical-scavenging activity, iron chelating activity, and scavenging of hydroxyl radicals. Cytoprotective activity was evaluated by the neutral red-based cytotoxicity test in 3T3-L1 cell culture in a wide range of concentrations. Assessment of intracellular ROS production was carried out using a 2,7-dichlorodihydrofluoresceindiacetate (DCFDA) fluorescent probe. Intracellular ROS production was induced using two common prooxidants (tert-butyl hydroperoxide, Fe2+ ions). We suggested an ontology-based model for the antioxidant and cytoprotective activity of humic acids based on experimental data and numerical models. This model establishes the way to further research on the biological effects of humic acids and provides a useful tool for numerical simulation of these effects. Remarkable antioxidant and cell protective activity of humic acids makes them a promising natural source of new pharmaceutical substances that feature a wide range of biological effects