French-Ukrainian Journal of Chemistry
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Synthesis of linear hetarenochromones based on 7-hydroxy-6-formyl(acetyl)chromones
Get PDFFused chromones are attracting increasing attention as novel therapeutic agents due to their wide distribution in nature, effective bioactivities and low toxicity. 6-Carbonyl-7-hydroxychromones proved to be versatile synthons for the synthesis of linear hetarenochromones by annulation of heterocycle to the chromone core. The present review is focused on the syntheses of furo[3,2-g]chromones, pyrano[3,2-g]chromones and some of their N-containing analogues, namely chromeno[6,7-d]isoxazoles, pyrano[3’,2’:6,7]chromeno[4,3-b]pyridine-5,11-diones and pyrano[3’,2’:6,7]chromeno[4,3-c]pyridine-5,11-diones based on the 7-hydroxy-6-formylchromones or 7-hydroxy-6-acetylchromones and shows the current state of research to date. The methods for the synthesis of the starting 7-hydroxy-6-formylchromones and 7-hydroxy-6-acetylchromones have been also mentioned. The biological activity of naturally occurring and modified synthetic linear hetarenochromones has been also represented
Relationship of the content of vitamin D and melatonin in blood serum and pineal gland calcifications in patients with malignant bone tumors
Get PDFThe aim of the study was to investigate the relationship between the vitamin D content, melatonin and the characteristics of pineal gland calcifications in patients with malignant tumors of the bones of the lower extremities. Vitamin D deficiency and pineal gland calcifications are observed in almost 100 % of patients with malignant tumors of the lower extremities’ bones. The high heterogeneity of calcifications and its dynamics during the treatment of patients may indicate the processes of their litholysis and dissolution
Method for Calculation of the Current Concentration of Alkali in the Electrolyte During the Water Electrolysis Process
Get PDFThe article proposes a method for calculation of the current concentration of alkali in the electrolyte, taking into account the consumption and replenishment of feed water in the electrolyzer, which allows to estimate the specific electrical conductivity of the electrolyte during electrolysis process. This is important to increase the efficiency of the water electrolysis process. The calculated change of the current concentration of alkali in the electrolyte in high-pressure electrolyzers taking into account the volume of produced hydrogen is given. With the usage of the proposed method, it is established that the current concentrations of alkali in the electrolyte during the operation of the developed high-pressure electrolyzers are in the range of optimal concentrations, where the specific electrical conductivity of the electrolyte is close to maximum and changes according to alkali concentration change
Numerical Simulation of the Process of Combustion of a Stoichiometric Hydrogen-Oxygen Mixture in a Steam Generator
Get PDFNumerical methods are used to study the process of combustion of a stoichiometric hydrogen-oxygen mixture. The mathematical models were validated using experimental data. The combustion process is modelled in the three-dimensional unsteady formulation. With account of the recommendations of other authors, the turbulent flows are described in the paper using the standard k-ε turbulence model. The Eddy Dissipation Model (EDM) is used to describe the process of combustion of the hydrogen-oxygen mixture. The description of the complex heat transfer between the gas, flame and walls in the paper accounts for radiant heat transfer by using the P1 model. The paper deals with combustion processes in a burner and a model steam generator. Numerical methods were used to evaluate the effect of inlet flow turbulisation, and the flow rate and the method of feeding extra water to the combustion chamber on the process of combustion of the stoichiometric hydrogen-oxygen mixture. The influence of the design and operating mode factors on the alteration of the flame-steam interface and on the flame extinguishing conditions were studied. The results obtained can be used in future in designing equipment that uses hydrogen as a fuel to increase nuclear power plant (NPP) manoeuvrability
Physicomechanical Properties of Epoxyurethane Biocomposites Strengthened with Hemp Wood Core
Get PDFHemp wood core (HWC) filled Si-containing epoxyurethane biocomposites, in which diane epoxy resin was replaced with epoxidized soybean oil (ESO), were obtained. It was shown that the tensile strength of ESO-containing polymer was higher, and the flexural strength was lower than those of original polymer. HWC was especially effective strengthening filler for modified epoxyurethanes, because in that case mechanical properties of composites were higher than those of unfilled polymer matrices. Particularly, flexural and tensile strength of unfilled epoxyurethane with maximum content of ESO were 8.1 and 6.8 MPa respectively, while in corresponding composite they reached 17.3 and 15.7 MPa
Aflatoxin content and health risks associated with consumption of some herbal products sold in Kampala, Uganda
Get PDFPersuasive adverts and exaggeration of health benefits from consumption of herbal products as well as the mental picture of ‘natural’ is ‘safe’ has boosted traditional medicine use in Uganda. However, herbal products may be unsafe due to the possibility of their contamination with mycotoxins. In this study, we quantified the levels of aflatoxins (B1, B2, G1 and G2) in Real Koff product, Eddagala ly’e kifuba n’e senyiga, Omusujja, Cough mixture and Fever herbal products sold in Kampala, Uganda using high performance liquid chromatography-tandem mass spectrometry. The associated consumption health risks were assessed using the hazard index method. Only aflatoxin B1 was detected in 60% of the samples, with 40% of these surpassing WHO guidelines of ≤ 5 µg/kg. The hazard indices were all less than 1, implying that Ugandans who heavily rely on the herbal products are exposed to aflatoxins at sublethal doses which may lead to chronic effects in the long run. Studies using a larger sample size should assess whether the current observation is a routine occurrence or a sporadic event
The enthalpies of mixing of ternary liquid Ag-Ca-Ge alloys
Get PDFPartial and integral enthalpies of mixing of the ternary Ag–Ca–Ge melts were determined for the first time by the high-temperature isoperibolic calorimetry at 1300–1550 K. The experiments were performed for six sections with a constant ratio of two components up to the molar fraction of the third component equal to 0.3. The enthalpies of mixing in this ternary system are exothermic values which increase in absolute value from the Ag corner of the concentration triangle towards the constituent binary Ca–Ge system. The minimum value of the integral enthalpy of mixing was obtained for Ca0.6Ge0.4 composition of the Ca–Ge binary system (about –58.00 kJ mol–1). The enthalpies of mixing of the ternary Ag–Ca–Ge melts are calculated for the whole concentration triangle by the Redlich-Kister-Muggianu method, taking into account the term of specific ternary interaction defined from our experimental data. The topology of the isoenthalpies of mixing is determined
Chemical characteristics and health risk assessment of potential toxic elementsin atmospheric PM10 around Ashaka cement factory, Gombe, Nigeria
Get PDFThe study determined the ambient mass concentrations, chemical composition and health risks associated with PM10 around Ashaka cement factory, Gombe, Nigeria. The samples were collected for the period (2019-2020). A total of 60 PM10 samples were collected and analyzed for seventeen elements using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The data collected were analyzed for descriptive and inferential statistics. The health risk was analyzed for hazard quotient (HQ), hazard index (HI) and cancer risk (CR). The average annual PM10 mass concentrations were found to be higher than the annual limit value for air quality standards (40 μgm-3). The HI estimated were >1 for children, while CR values of Cd, Ni, As and Cr for children and Cr for adults were higher than the acceptable value 10-6, indicating children are more probable to develop cancer than adults
Biological Evaluation of 3-Aminoisoquinolin-1(2H)-one Derivatives as Potential Anticancer Agents
Get PDFAnticancer activity of a series of 3-(hetaryl/aryl)amino substituted isoquinolin-1(2H)-ones has been studied within the international scientific program “NCI-60 Human Tumor Cell Lines Screen”. Screening was performed in vitro on 60 cell lines of lungs, kidneys, CNS, ovaries, prostate, and breast cancer, epithelial cancer, leukemia, and melanoma. The most effective compounds were those with thiazolyl or pyrazolyl substituent at 3-amino group and had no substituents at C(4) of the isoquinoline cycle. We identified a new lead compound, 3-(1,3-thiazol-2-ylamino)isoquinolin-1(2H)-one 12, which effectively prevents tumor cell growth (average lg GI50 = -5.18, lg TGI = -4.1, lg LC50 > -4.0) with good selectivity
Hetarenocoumarins based on 7-hydroxy-3-(benzothiazol-2-yl)coumarin
Get PDFThe syntheses of angular hetarenocoumarins, namely chromeno[8,7-e][1,3]oxazin-2-ones and furo[2,3-h]chromen-2-one, have been accomplished starting from 7-hydroxy-3-(benzothiazol-2-yl)-coumarin using aminomethylation and formylation reactions