Force decay of polyethylene terephthalate glycol aligner materials during simulation of typical clinical loading/unloading scenarios

Background This in vitro study investigated the effect of three distinct daily loading/unloading cycles on force delivery during orthodontic aligner therapy. The cycles were applied for 7 days and were designed to reflect typical clinical aligner application scenarios. Materials and methods Flat polyethylene terephthalate glycol (PET-G) specimens (Duran®, Scheu Dental, Iserlohn, Germany) with thicknesses ranging between 0.4 and 0.75 mm were tested in a three-point-bending testing machine. Measurements comprised loading/unloading intervals of 12 h/12 h, 18 h/6 h, and 23 h/1 h, and specimens were exposed to bidistilled water during loading to simulate intraoral conditions. Results A very large decay in force for the PET‑G specimens could already be observed after the first loading period, with significantly different residual force values of 24, 20, and 21% recorded for the 12 h/12 h, 18 h/6 h, and 23 h/1 h loading/unloading modes, respectively (Mann–Whitney U test, p < 0.01). In addition, further decays in force from the first to the last loading period at day 7 of 13.5% (12 h/12 h), 9.7% (18 h/6 h), and 8.4% (23 h/1 h) differed significantly among the three distinct loading modes (Mann–Whitney U test, p < 0.01). Conclusion Although the initial material stiffness of PET‑G is relatively high, the transmission of excessive forces is attenuated by the high material-related force decay already within a few hours after intraoral insertion.

The optical and electrical non-invasive methods of measurement for glucose concentration in biological liquids

The article describes the radio-wave and optical methods of determining glucose concentration. The radio-wave method is based on the use of a sensor with a resonant frequency that is displayed when in contact with highly lossy materials and with an extended near-field zone in the resonance area. The optical method is based on studying the influence of glucose concentration (0–20 mmol/l) in bidistilled water on absorption spectra in the range of 190-1000 nm. The article presents the results of the experimental test of the near-field sensor with the pre-produced biological media imitating the human body tissues, and the results of the optical method demonstrate the possibility to measure the concentration with the use of an optical emitter with a wave length of 830 nm.

Antioxidant content of oat talkan made from sprouted grain

Одним из путей повышения функциональной ценности пищевых продуктов является увеличение содержания в них химических соединений, обладающих антиоксидантной активностью. Последние, как известно, играют важную роль в профилактике различных заболеваний человека. Антиоксидантами богаты зерновые культуры, на основе которых изготавливаются наиболее употребляемые населением продукты питания. Целью данного исследования являлось определение величины суммарного содержания антиоксидантов (ССА) в зерновом сырье на разных этапах производства хакасского национального продукта талган, изготовленного из пророщенного зерна овса. Овес выращивали на территории Бейского района Республики Хакасия в 2019 г. Очищенное зерно проращивали при комнатной температуре в течение 56 ч, затем его просушивали и обжаривали при температуре 180…200 °С в течение 10-15 мин, а далее измельчали и просеивали через сита с ячеей 0,9 мм. В результате получали продукт талган и отходы в виде отрубей. Для определения уровня ССА в зерне использовали два растворителя - горячую бидистиллированную воду и 70 %-ный этиловый спирт. Измерение значения ССА выполняли на приборе «Цвет Яуза-01-АА». Среди исследуемых образцов более высокие показатели ССА были зарегистрированы при использовании в качестве элюента горячей бидистиллированной воды. В работе выявлен эффект увеличения уровня ССА в конечном продукте по сравнению с исходным сырьем после этапа проращивания зерна в среднем в 2 раза, а после этапов обжаривания и измельчения в 2,1 раза. Величина ССА в отрубях превышала таковую в исходном зерне в среднем на 47 %. Таким образом, в результате исследований было установлено, что введение в технологию изготовления овсяного талгана дополнительного этапа, заключающегося в проращивании зерна, является одним из эффективных способов повышения величины ССА в полученном на его основе продукте. One of the ways to increase the functional value of food products is to increase the content of chemical compounds that have antioxidant activity. The latter are known to play an important role in the prevention of various human diseases. Antioxidants are rich in cereals, on the basis of which the most commonly consumed food products are made. The purpose of this study was to determine the value of the total content of antioxidants (TCA) in grain raw materials at different stages of production of the Khakass national product talgan, made from sprouted oat grain. Oats were grown on the territory of the Bey district of the Republic of Khakassia in 2019. The purified grain was sprouted at room temperature for 56 hours, then it was dried and fried at a temperature of 180…200 oC for 10-15 minutes, and then ground and sieved through sieves with a mesh of 0.9 mm. As a result, the product talgan and waste in the form of bran were obtained. To determine the level of TCA in the grain, two solvents were used - hot bidistilled water and 70 % ethyl alcohol. The TCA value was measured on the device «Color Yauza-01-AA». Among the studied samples, higher TCA values were recorded when using hot bidistilled water as an eluent. The paper reveals the effect of increasing the level of TCA in the final product in comparison with the initial raw material after the stage of grain germination by an average of 2 times, and after the stages of roasting and grinding by 2.1 times. The value of TCA in bran exceeded that in the original grain by an average of 47 %. Thus, as a result of research, it was found that the introduction of an additional stage in the production technology of oatmeal talgan, which consists in the germination of grain, is one of the effective ways to increase the value of TCA in the product obtained on its basis.

Testing the possibility of using desiccators to study the aerosol effect of liquid deicing material

Introduction. In many countries, there is an additional group of pollutants - deicing materials (DIM) in winter. Salt-containing DIM is one of the factors for increasing the content of PM2.5 and PM10 in the air. The purpose was to determine the possibility of using desiccators to study the aerosol effect of liquid deicing material, identify the chemical composition in the air at spreading liquid DIM in various ways, and establish the calculated doses for conducting a toxicological experiment to study the DIM aerosol effect on the organism of warm-blooded animals. Materials and methods. A model experiment was conducted in airtight containers (desiccators) using a liquid DIM that includes NaCl and CaCl2. All chemical compounds were captured in air pumping from the desiccator into a bubbler tank with bidistilled water and then analyzed using ion chromatography. Results. When comparing the obtained results of main DIM components contained in the air inside desiccators with the maximum permissible concentrations, the excess of Cl- was detected both for the highest single concentration of 0.1 mg/m3 and for the average daily concentration of 0.03 mg/m3. When applying DIM at a dose exceeding ten times the recommended norms for liquid the DIM, an excess level of the maximum permissible concentration for chlorine (but not for sodium and calcium) is observed. Conclusion. The method of DIM studying in desiccators is indicative in terms of the choice of concentrations and studying mechanisms of reagent intake for subsequent DIM research conduction using laboratory animals.

Functional value of a talgan made from sprouted wheat and barley

The aim of this study was to analyze the total content of antioxidants (TCA) at different stages of production of the Khakass national product talgan, made from sprouted wheat and barley. Grain crops were grown on the territory of the Bey district of the Republic of Khakassia, which is characterized by favorable climatic conditions from the point of view of growing grain with an increased content of antioxidants. To determine the TCA value in the grain, two solvents were used – hot bidistilled water and 70% ethanol. The TCA measurement was performed on the device "Color Yauza-01-AA". Among all the grain samples studied, higher values were recorded when using hot bidistilled water as an eluent. It was found that the germination process did not reduce the taste qualities of the grain product. The value of the TCA in talgan, made on the basis of sprouted barley grain, was higher in comparison with wheat by 34%. The effect of increasing the level of TCA in the product in comparison with the initial raw material after the stage of grain germination in wheat and barley, respectively, by 1.5 and 2 times, and after the stages of roasting and grinding by 2 and 2.5 times. The value of FSA in bran exceeded that in the original grain by 44 and 65% for wheat and barley, respectively. Thus, as a result of the research, it was found that regardless of the studied crop (wheat, barley), the process of germination of grain is one of the effective ways to increase the value of TCA in the talgan product made on its basis.

Study of the influence of interfering ions of heavy metals and various sample preparation on the determination of mercury impurity in protamine sulfate by stripping voltammetry

Aim. To determine the content of mercury in protamine sulfate samples with different sample preparation. To study the effect of interfering ions on the content of mercury impurity in protamine sulfate by stripping voltammetry (SV). Materials and methods. We used a solution for injection of protamine sulfate, batches 515091, 514062, 514111; for sample preparation — various options for dilution and precipitation. Dilution was carried out with bidistilled water, and the precipitation of proteins — with sodium tungstate in 2 options. Mercury impurities were determined by the SV method. Results. The mercury content in protamine sulfate samples was 0.000417 ± 0.00140 and 0.000420 ± 0.00152 mg/l when diluted with water 1 : 2 and 1 : 1 respectively and 0.000462 ± 0.00131 and 0.000459 ± 0.00121 when precipitated with tungstate in options 1 and 2 respectively. With the addition of an interfering ion, for example, Cu2+, the content of mercury in the medicinal product was 0.000606 ± 0.00015, 0.000452 ± 0.00013 and 0.0004212 ± 0.00011 mg/l for protamine sulfate batches 514062, 515091 and 514111 respectively, which does not exceed the values determined by the product specification. The addition of Pb2+, Fe2+, Zn2+, Cu2+, and Cd2+ ions also had no effect on the determination of the mercury content in protamine sulfate samples. Conclusion. To determine the mercury impurity in the protamine sulfate, special sample preparation is not required. Ions of Cu2+, Pb2+, Fe2+, Cd2+, Zn2+ do not affect the result of determining the mercury content in protamine sulfate samples by the SV method, which indicates a high selectivity of the method used.

Oat talgan as a source of antioxidants

The purpose of the study was to analyze the total content of antioxidants (TAC) in the national Khakass product talgan consisted of oats grain. Talgan was prepared according to traditional (frying, grinding) and innovative (grinding, frying) methods. In this series of experiments, three oat cultivars were used: Argument (chaffy caryopsis), Tubinsky (chaffy caryopsis) and Golets (bare-grained). All samples were grown on the territory of the Beysk state section of the Republic of Khakassia, which was characterized by favorable climatic conditions for growing grain with a high antioxidant content. For TAC determination in grain, 2 solvents were used - bidistilled water and 70% ethanol. The TAC measurement was performed on ‘Tsvet Yauza-01-AA’. Gallic acid was used as a reference sample. In oat talgan, prepared according to the traditional method from chaffy caryopsis samples, the total content of antioxidants had a higher value than that before processing (regardless of the nature of eluting solvent). However, the opposite tendency was observed in the case of bare-grained sample. Higher rates among all samples were recorded when using hot bidistilled water as eluting solvent. The use of innovative method for production of talgan showed that the total content of antioxidants in all samples had higher values in comparison with the traditional method. Using a three-factor analysis, it was found that the TAC values in oat talgan were two-thirds dependent on the method of preparing the product; solvent nature and genotype affected much less.

First Report on the Occurrence of an Aggressive Pathotype, 734, of Plasmopara halstedii Causing Sunflower Downy Mildew in Hungary

Downy mildew of sunflower (Helianthus annuus L.) is caused by Plasmopara halstedii (Farl.) Berl. et de Toni, leading to significant losses in crop production worldwide. The number of new and more aggressive pathotypes has increased rapidly over the last 10 years in Europe (Virányi et al. 2015, Bán et al. 2018), therefore, constantly monitoring the distribution of races is an important task. As part of regular surveys in June 2019, severe downy mildew was identified in some regions, appearing as chlorotic lesions along the veins of the adaxial side and white sporulation on the abaxial side of the leaves of severely stunted hybrids containing PI6 and PI7 resistance genes. The identification of the pathogen was performed microscopically based on morphological characteristics (average size of sporangia: 28x20 µm). Disease incidence (the ratio of diseased plants) ranged between 10 and 30% per field in three regions and resulted in moderate yield loss. Isolates (defined as a lesion per leaf) were collected from 4 to 8 infected leaves of each hybrid by region and stored at -70°C. Two, one and one isolates of P. halstedii were selected and characterized from the southeastern (Békés County), northern (Nógrád County) and northeastern (Borsod-Abaúj-Zemplén County) regions of Hungary, respectively. The pathotype of the four isolates was determined using the international standardized nomenclature method reviewed by Trojanová et al. (2017), including nine sunflower differential inbred lines (HA-304, RHA-265, RHA-274, PMI-3, PM-17, 803-1, HAR-4, QHP2 and HA-335). Zoosporangia from frozen sunflower leaves were washed off into bidistilled water and the concentration was adjusted to 3.5x104 sporangia/ml using a hemocytometer. Three-day-old seedlings with a radical of 1 to 1.5 cm long were immersed in the sporangial suspension and kept at 16°C overnight (Cohen and Sackston 1973). Inoculated seedlings were planted into trays containing clear moistened perlite (d = 4 mm) and grown in a growth chamber with a photoperiod of 12 h. The experiment was carried out twice with each isolate using 15 seeds/differential line with two replicates. Bidistilled water was sprayed on the plants 9 days after inoculation, and then trays were covered with a black polyethylene bag and maintained at 19°C overnight to induce sporulation. The first disease assessment was done based on cotyledons bearing white sporulation. Next, a second evaluation was performed 21 days after inoculation assessing stunting of the plants, chlorotic lesions on true leaves and damping-off. All 4 isolates examined caused disease on differential lines HA-304, RHA-265, RHA-274, PMI-3, PM-17 and HA-335, whereas the other lines showed no symptoms and signs of sunflower downy mildew. As a result, it was concluded that the presence of P. halstedii pathotype 734 was confirmed. This pathotype is likely widespread in Hungary as it could be detected from three different regions. Moreover, the possibility that pathotype 734 is present in Hungary has been raised before (Iwebor et al. 2018). This pathotype is already widespread in the USA and Russia and is considered to be highly aggressive, since it was able to infect hybrids with resistance genes PI6 and PI7 (Iwebor et al. 2018, Spring 2019). To our knowledge, this is the first report of pathotype 734 of P. halstedii in Hungary and Central Europe. Continuous monitoring and incorporation of new resistance genes into sunflower hybrids are essential steps in the future to control P. halstedii.

Fabrication of Silver- and Zinc-Doped Hydroxyapatite Coatings for Enhancing Antimicrobial Effect

This study develops, for the first time, composite coatings based on silver and zinc doped hydroxyapatite in chitosan matrix (AgZnHApCs). The AgZnHApCs composite coatings were prepared by dip coating method. The hydroxyapatite (HAp), biocompatible material for regenerating and strengthening damaged bones were doped with silver and zinc ions and coated with chitosan in order to produce a uniform and homogenous coating with biocompatibility and antimicrobial properties. The stability of AgZnHApCs suspensions was evaluated by ultrasound measurements. The value of stability parameters of AgZnHApCs suspension is in good agreement with the value of bidistilled water used as reference fluid. Homogeneously dispersed solutions of AgZnHApCs were synthesized to endeavor to optimize the physico-chemical and biological characteristics of the coatings obtained at room temperature. The AgZnHApCs composite suspension and coatings were analyzed using various investigation techniques, such as X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenylte-2H-tetrazolium bromide) assay and antimicrobial studies. The optical spectroscopy, atomic force microscopy (AFM), metallographic examination and X-ray photoelectron spectroscopy (XPS) on AgZnHApCs composite coatings were also conducted. Cell culture and MTT assays demonstrate that AgZnHApCs composite suspension and coatings have no negative effect on the cell viability and proliferation. The cell morphology was not affected in presence of AgZnHApCs composite suspension and coatings. The antimicrobial assays conducted against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Candida albicans ATCC 90029 microbial strains revealed that both the AgZnHApCs composite suspension and coatings exhibited great antimicrobial properties.

New Pre-reacted Glass Containing Dental Composites (giomers) with Improved Fluoride Release and Biocompatibility

The aim of the present work was to prepare a series of novel restorative giomers and investigate the morphology, the physico-chemical properties (residual monomer, fluoride release), and the cytotoxicity of the new materials. The experimental giomers were prepared as light-cured pastes by blending different resin matrices comprising aromatic/aliphatic/urethane (di) methacrylates, with hybrid fillers containing pre-reacted glasses (PRGs), a radiopaque glass, and nano fluorhydroxyapatite. Polyalkenoic acids based on acrylic acid/itaconic acid/N-acryloyl -L-leucine modified or not with methacrylic groups, together with a superficially active glass, were used to prepare the PRGs. The fluoride ion release of the experimental giomers was investigated within a period of 60 days of storage in bidistilled water while using a fluoride ion selective electrode. Beautifil II commercial product was used as a reference. Cell cytotoxicity tests were done in vitro, in accordance with ISO 10993-122012 proceedings. Human dermal fibroblasts and umbilical endothelial vein cultures were used. The values that were obtained for cumulative fluoride release for all experimental giomers were higher than for the Beautifil II product, being more than twice the ones that were obtained for the commercial product after 60 days of storage in bidistilled water. The experimental biomaterials showed similar and/or better results when compared to the commercial one; this effect was maintained in all tested conditions.