135 research outputs found

    Environmental state and buffering properties of underground hydrosphere in waste landfill site of the largest petrochemical companies in Europe

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    The article examines the waste landfill site of PJSC "Nizhnekamskneftekhim" built 1982. Particular attention is paid to the volume of disposed wastes and peculiarities of landfill operation. It has been revealed that the landfill negatively impacts groundwater. The increase in groundwater level and contamination degree is dependent on recharge from infiltration of precipitation that interacts with the waste in the landfill cells. Groundwater contamination follows the longitudinal distribution pattern, with maximum intensity reaching in the nearest area of the landfill. With increasing distance, concentration of all pollutants sharply reduces. Within three kilometers away from the landfill, groundwater turns to its background values indicating its quality. The landfill discharges oil, phenols, formaldehyde, benzol, toluene, xylene, ethylbenzene, and iron and, to a lesser extent, sulfates, chlorides and barium into the underground hydrosphere. The overlimiting concentrations of other components are caused by intensive leaching from the rocks by aggressive carbonic acid water. The concentrations of hydrocarbonates can reach 8 g/l in the groundwater within the landfill and its nearest area, however, under natural conditions, they do not exceed 0.4 g/l. This is only possible in a case of partial activity of carbon dioxide associated with destruction of organic matter disposed in the landfill. One of the processes that play an important role in groundwater quality recovery is mixing of contaminated groundwater with infiltrating precipitation

    AUTODIDACTIC FOR PARENTS OF CHILDREN STUDYING IN MULTI-ETHNIC SCHOOL ENVIRONMENT

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    Purpose: The article is aimed at describing a model of self-education of primary school children's parents and the results of its testing in a primary school in a multi-ethnic educational space. The leading technology of organizing self-education for parents of primary students and formation of their methods of auto-didactics is the technology of poly directional pedagogical counseling. Methodology: The following methods of measuring the effectiveness of the offered program were used: SWOT - analysis of educational problems of primary school children in a multi-ethnic educational organization, analysis of research data on related topics, pedagogical modeling, studying students' work, observation, and survey methods with graphical interpretation of the data. Result: The result of the study was a unique model of inclusion of primary students’ parents in the educational space of a multi-ethnic school. In accordance with the authors' model, an awareness program was launched for parents of primary school children. Applications: The research materials can be useful for primary school teachers, for parents of primary students, as well as for specialists in the system of additional education in working with multi-ethnic children groups, as well as for social teachers in working with migrant families to build a non-conflict educational environment. Novelty/Originality: The originality of the study lies in the development of a model for the inclusion of parents of younger schoolchildren in the educational space of a multi-ethnic school through parental self-education organized by school teachers

    Synthesis of novel 6-substituted sulfur-containing derivatives of pyridoxine

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    An efficient synthesis of novel 6-substituted derivatives of pyridoxine was achieved. The reactions of various thiols with mono-, bis-, and tris(hlorine) derivatives of 6-methyl-2,3,4-tris(hydroxymethyl)pyridin-5-ol (6-hydroxymethylpyridoxine) gave sulfur-containing derivatives of pyridoxine. © 2012 Elsevier Ltd. All rights reserved

    What affects the neurovisualisational detection of ischemic stroke?

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    Introduction. The incidence of stroke is 2.5–3 cases per 1 000 population per year, mortality – 1 case per 1 000 population per year. According to various data, up to 20% of computed tomography (CT) scans performed on the first day do not reveal signs of  an ischemic focus.Aim of the study. To assess the detectability of acute ischemia foci using CT, depending on the location of the foci, the timing of  neuroimaging, the severity of stroke, and other indicators.Material and methods. We analyzed 100 cases of acute cerebrovascular accident (ACV) by ischemic type. The timing of the CT scan, glucose level, coagulogram parameters, NIHSS scores at admission, focus localization, the presence of atherosclerosis of the arteries of the head, and atrial fibrillation were taken into account. Patients were divided into two groups depending on the fact of detection of the focus during the primary tomographic examination. Repeated neuroimaging (magnetic resonance imaging) was performed in 54 patients.Results. In the “CT-negative” group, stem strokes predominated (p = 0.01), patients were younger (р = 0.038), and there were significantly more women than men (р = 0.00006). An increase in glucose over 8 mmol/l, on the contrary, was more often detected in the “CT-positive” group (14 cases in “CT-positive” against 5 cases in “CT-negative” group, p = 0.022). NIHSS scores ≥ 5 were found in 24 patients (47%) in the “CT-positive” group and in 13 patients (26.5%) in the “CT-negative” group (p = 0.034).Conclusions. Cases of stroke that are not detected on CT scan upon admission to the hospital are more common among women, with stem localization, are associated with low NIHSS scores. High glucose levels at admission is associated with the detection of ischemic foci during the initial CT examination

    Experimental and theoretical study on 6-substituted pyridoxine derivatives. Synthesis of Cyclic 2,4,5,6-Tetrakis-(hydroxymethyl)pyridin-3-ol Acetonides

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    © Pleiades Publishing, Ltd., 2011. Synthetic approaches to three cyclic 2,4,5,6-tetrakis(hydroxymethyl)pyridin-3-ol acetonides were developed. Among seven possible mono- and diketals, six-membered cyclic ketal incorporating the hydroxymethyl group in the 4-position turned out to be the most thermodynamically favorable. The experimental data were consistent with the results of quantum-chemical calculations of the Gibbs energies of formation of different acetonides. The structure of the isolated compounds was studied by X-ray diffraction

    Conversion processes for high-viscosity heavy crude oil in catalytic and noncatalytic aquathermolysis

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    © 2014 Springer Science+Business Media. We have conducted experiments on noncatalytic and catalytic aquathermolysis of high-viscosity heavy crude oil from the Ashal'cha field (Tatarstan) in the presence of a crude oil-soluble nickel- and cobalt-containing catalyst, a proton donor, and a rock-forming mineral. We have identified the characteristic features of the change in the constituent composition, the hydrocarbon composition, and the fractional composition, the rheological properties of the crude oils, the average molecular weight of the asphaltenes for catalytic and noncatalytic conversion processes. For catalytic aquathermolysis, we established significant de novo formation of light 70°C-250°C fractions (by 23 wt.%), n-alkylbenzenes, an increase in the oil content by a factor of 1.3, a decrease in the resin content by a factor of 1.7, and a decrease in the viscosity by 98 rel.%. The major difference between the conversion of crude oil in the presence of the catalyst and the proton donor involves activation of degradation reactions at C-C, C-N, C-O, C-S bonds and blocking of polymerization reactions and accordingly less coke formation. We observed sorption of the catalyst components on rock

    Study of "racemic compound-like" behavior of diastereomeric mixture of pinanyl sulfoxides by x-ray diffraction, ir spectroscopy, and DFT calculations

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    The oxidation of a β-hydroxysulfide in the pinane series by use of mchloroperbenzoic acid resulted in the formation of the corresponding β-hydroxysulfoxide as a mixture of two diastereomers in 4:5 ratio. According to single-crystal X-ray diffraction (XRD) results, it is established that the diastereomeric mixture of sulfoxides crystallizes in the "racemic compound-like" manner under formation of asymmetric dimers through S=O··H-O interactions. This asymmetric dimer formed from diastereomeric molecules is a structural unit in both crystal modifications, the triclinic and the monoclinic one. The behavior of the diastereomeric mixture of pinane derived sulfoxides in crystals, melts and in tetrachloromethane solutions was studied by IR spectroscopy. The density functional theory (DFT) method with 6-31G (d, p) basis set was used to calculate the optimized geometrical parameters and vibrational frequencies of different associates in solution. The calculated vibrational frequencies are compared with experimental IR spectra. Copyright © 2014 Taylor & Francis Group, LLC

    Bis-phosphonium salts of pyridoxine: The relationship between structure and antibacterial activity

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    A series of 23 novel bis-phosphonium salts based on pyridoxine were synthesized and their antibacterial activities were evaluated in vitro. All compounds were inactive against gram-negative bacteria and exhibited the structure-dependent activity against gram-positive bacteria. The antibacterial activity enhanced with the increase in chain length at acetal carbon atom in the order n-Pr > Et > Me. Further increasing of length and branching of alkyl chain leads to the reduction of antibacterial activity. Replacement of the phenyl substituents at the phosphorus atoms in 5,6- bis(triphenylphosphonio(methyl))-2,2,8-trimethyl-4H-[1,3]-dioxino[4,5-c] pyridine dichloride (compound 1) with n-butyl, m-tolyl or p-tolyl as well as chloride anions in the compound 1 with bromides (compound 14a) increased the activity against Staphylococcus aureus and Staphylococcus epidermidis up to 5 times (MICs = 1-1.25 μg/ml). But in practically all cases chemical modifications of compound 1 led to the increase of its toxicity for HEK-293 cells. The only exception is compound 5,6-bis[tributylphosphonio(methyl)]-2,2,8- trimethyl-4H-[1,3]dioxino[4,5-c]pyridine dichloride (10a) which demonstrated lower MIC values against S. aureus and S. epidermidis (1 μg/ml) and lower cytotoxicity on HEK-293 cells (CC50 = 200 μg/ml). Compound 10a had no significant mutagenic and genotoxic effects and was selected for further evaluation. It should be noted that all bis-phosphonium salt based on pyridoxine were much more toxic than vancomycin. © 2013 Elsevier Ltd. All rights reserved

    Synthesis and antibacterial activity of novel phosphonium salts on the basis of pyridoxine

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    A series of 13 phosphonium salts on the basis of pyridoxine derivatives were synthesized and their antibacterial activity against clinically relevant strains was tested in vitro. All compounds were almost inactive against gram-negative bacteria and exhibited structure-dependent activity against gram-positive bacteria. A crucial role of ketal protection group in phosphonium salts for their antibacterial properties was demonstrated. Among synthesized compounds 5,6-bis[triphenylphosphonio(methyl)]-2,2,8-trimethyl-4H-[1,3] dioxino[4,5-c]pyridine dichloride (compound 20) was found to be the most effective towards Staphylococcus aureus and Staphylococcus epidermidis strains (MIC 5 μg/ml). The mechanism of antibacterial activity of this compound probably involves cell penetration and interaction with genomic and plasmid DNA. © 2013 Elsevier Ltd. All rights reserved

    Neuroendocrine Tumours: a Literature Review

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    Neuroendocrine tumours (NETs) are a heterogeneous group of malignant neoplasms with diverse morphology and nomenclature. Well-differentiated NETs were historically termed carcinoid tumours, which entailed abundant confusion and misclassification. Cross body-localised NETs have been described from the central nervous system, respiratory and gastrointestinal tracts, larynx, thyroid, skin, breast and urogenital system. The evidence on NET prevalence is diverse, with selected sources estimating a 0.5% rate among total malignancies diagnosed. Carcinoid syndrome is a known important associate of NETs. Its presence resulting from the amine and peptide hypersecretion often facilitates the NET diagnosis, and curative surgery becomes a treatment of choice, if technically feasible. Adjuvant therapy is ambiguous. When surgery is impractical due to a usually advanced NET at diagnosis, drug therapy is adopted to relief symptoms and control the disease
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