Vol. 55 No. 3 (256) (2021)

The interaction of N-monomethylol urea with maleic anhydride is studied. The product of this reaction forms an oligomeric monomer by condensation with chitosan. This oligomeric monomer has a capacity of copolymerization in aqueous media with other soluble monomers such as acrylic acid forming crosslinked water-swelling copolymer. The products obtained in mentioned above reactions were investigated by IR-spectroscopy and elemental analysis.

The optimal conditions of the method, applicable during forensic chemical examinations, were elaborated. Particularly, the investigation of the conditions for the isolation of Nifedipine from liver and skeletal muscle tissues, the identification of the isolated Nifedipine by TLC method and checking the accuracy of the method using HPLC was carried out. As a result, a new alternative express method for the isolation and further identification of Nifedipine from different biomaterials was elaborated. The method is quite fast, accurate and much cheaper.

Skin permeability of Sevan trout has been studied during 30 min in different solutions: in distilled water, in 70% ethanol, in solution of 0.125 M KCl. The permeability was measured by methylene blue. It was shown that the skin permeability for this dye changes depending in what solution these shreds of Sevan trout were kept and from which side the shred was tightened. It was also shown that distilled water, solution of 0.125 M KCl and ethanol cause structural changes in the skin layers of the Sevan trout, in particular the epidermis.

In this work the effect of EMI EHF on change of the surface tension coefficient of human blood plasma under the effect of acetylsalicylic acid (ASA) as well as dependence of this parameter change on ASA effect duration and electromagnetic irradiation duration have been studied. It was shown that the plasma irradiation results in changing of the surface tension coefficient. At irradiation during 60 min the value of the given parameter increases, though, the further repeating irradiation does not induce an enhancement; some decrease is observed, but it remains higher, than the original value. It was also shown that ASA prevents development of relevant changes of blood plasma properties, particularly the value of the surface tension coefficient of plasma under the effect of EMI in millimeter range changes.

Physicochemical pretreatment of lignocellulosic corn fruit wastes (husk, shank, stalk) has been done. E. coli K12 growth, ORP kinetics, and H₂ production were followed upon utilization of corn waste hydrolysates (CWH) separately and their mixture. During the bacterial log growth phase with the decrease of medium pH the readings of Pt electrode from positive to low negative values (~ –450±10 mV) were observed, with the yield ~ 0.75 mmol H₂ /L and 0.29 bacterial cell dry weight g/L biomass in CWH based medium. Meat (chicken wastes) broth supplementation ~2 fold enhanced both E. coli biomass formation and H₂ production on CWH mixture.

Green algae are promising objects of biotechnology due to their high growth rates and the ability to produce biologically active compounds. Moreover, green algae are able of generating biohydrogen (H₂), which is of interest in biofuels technology. In this study an application of distillers grains with solubles (DGS), the main waste generated during ethanol production, as a feedstock for enhancing the yield of H₂ in green alga Chlorella vulgaris IBCE C-19 was investigated. The results obtained showed the possibility of using of this waste as a valuable source of natural biological compounds in H₂ production.

The article presents experimental data on the effectiveness of drugs that could stimulate the start of metabolic adaptation during the development of methemoglobinemia. The modeling of this type of hemic hypoxia led to the disruption of antioxidant protection, resulting in a rather significant decrease of superoxide dismutase and catalase (primary antioxidant enzymes) in the blood plasma of tested animals. We have established that anti-hypoxic activity was higher with the use of mexidol compared to the use of tocopherol. The differences in the indicators can perhaps be explained by the different mechanisms of action of the used antioxidants. The state of methemoglobinemia has also led to increased concentrations of medium-size molecules in the blood plasma. The use of mexidol and tocopherol did not show any significant effect on normalization.

There are some aspects of the proteins «self-organization» that are not well studied, understanding the relationship between conformational folding linked with the formation of a disulfide bond is important and challenging from both biophysical and biochemical perspectives. In the studies, an attempt was made to elucidate the role of thiol groups in maintaining of native conformation and activity of arginase I and II of various organ origins. It was identified that depending on the stage of enzyme reactivation and the stability of the conformational state of the formed oligomers, para-chloromercuribenzoate affects the «self-organized» oligomers in different ways.

Saccharomyces cerevisiae is an essential component of human civilization because of its extensive use in food industry. At the point of industrial usage it is very important to get large amount of biomass but many factors causes yeast's viability loss and death. The aim of this work was to study the peculiarities of growth parameters – specific growth rate (SGR, μ, growth yield) of S. cerevisiae wine and beer strains under different external conditions, as well as pH and oxidation-reduction potential (ORP) changes during growth. It was shown that under aerobic cultivation, the conditions 30℃ and pH 6.5 are more favorable for the growth of 2 strains (ATCC 9804, μ = 0.398; ATCC 13007, μ = 0.407), where they can enhance the biomass, and under microaerobic conditions the pH 5.0 and 37℃ are more favorable (ATCC 9804, μ = 0.35; ATCC 13007, μ = 0.436). During aerobic conditions, lower ORP values are established which did not depend on growth temperature and external pH. Under microaerobic conditions until the establish¬ment of the stationary phase (24 h) pH dependent changes of ORP were established. Obtained results will help to clarify the biochemical, biophysical and bioenergetic phenomena of yeast survival that can enhance the biomass growth and yield and thus applied industrial scale.

As a result of studying the biota of the agaricoid basidiomycetes of the Shikahogh State Reserve, 148 species of fungi are found, from which 97 species are edible, 48 species – poisonous and 52 species have medicinal properties. Мacromycetes have great potential for use in medicine and economy.

The aim of this research was to reveal an impact of anemia on the quality of life (QL) score, as well as on different subscales of children's QL. The subjects of the research were 3 months–3 years old 100 children selected from two pediatric polyclinics of Yerevan. QL were measured by QUALIN questionnaire. A significant decrease in the total score and other domains of the QUALIN questionnaire scores were indicative for an impact of anemia on QL of the early aged children. Most affected subscale in case of anemia was «Ability to remain alone».

The phytoplankton dynamics in the Debed River, Armenia, was investigated. Water samples for phytoplankton quantitative and qualitative analyses were collected from 4 sites along the river once per season in April, July and September 2017. The results of the study have revealed the characteristics of the spatiotemporal distribution of phytoplankton community in the Debed River.

Bryophytes are rich in a variety of secondary biological active compounds, thus provide a great potential for biotechnological and biopharmaceutical applications. Bryophytes contain potentially useful natural products, including polysaccharides terpenoids, lipids, amino acids and phenylpropanoids. Bryophytes isolated compounds and extracts have cytotoxic, antimicrobial activities. The result of our research indicate the presence in the extracts of bryophytes collected in Armenia, the entire spectrum of amino acids, especially essential ones. Also revealed in some species a certain amount of nitrogen – 840 mg/g, which indicates a more intensive synthesis of nonessential amino acids. The results obtained can be used in medicine, pharmacology.

In this study, chromatographic conditions were developed for the separation and quantification of N-nitrosodimethylamine (NDMA) by HPLC. Our method would be useful for the rapid screening and quantification of NDMA impurity in Metformin hydrochloride, Losartan potassium, Valsartan and Ranitidine drugs substance and its products. The chromatographic separation was achieved on a Phenomenex C18 column (250 mm, 5 µm, 4.6 mm) by multistep gradient elution, using a water-acetonitrile mobile phase containing 0.1% formic acid, which provided better c hromatographic separation. Column temperature was maintained at 30℃; mobile phase flow rate: 1 mL/min; wavelength: 254 nm; and injection volume of 20 μL.