FLOW OF SACBROOD DISEASE IN CREATION OF INFERTILE PERIOD AT BEE COLONIES IN COMPARISON WITH THE USE OF PROBIOTIC «APINORMIN», NANOSIZED CERIUM DIOXIDE, PLANT ORIGIN PREPARATION «NI NU NA»

На бджолиних сім’ях, уражених мішечкуватим розплодом, визначено ефективність безрозплідного періоду порівняно з обробленням сімей пробіотиком «Апінорміном» (4%), нано-розмірним діоксидом церію («Нано-СеО2») (0,5%), препаратом рослинного походження «Ні Ну На» (1%), діючою речовиною якого є витяжка з виноградних кісточок. Установлено, що жоден із випробуваних препаратів не мав лікувального ефекту за мішечкуватого розплоду. Ефективним заходом виявилося створення у хворих сім’ях безрозплідного періоду на термін виведення нових маток. Оскільки аналогічні дані ми отримали раніше за аскосферозу та мішечкуватого розплоду, то цей технологічний прийом можна рекомендувати при більшості інфекційних захворювань розплоду у бджіл. Ключові слова: бджолині сім’ї, мішечкуватий розплід, безрозплідний період, пробіотик «Апінормін», нано-розмірний діоксид церію («Нано-СеО2»), препарат рослинного походження «Ні Ну На».

Morphology, phase and chemical composition of the nanostructures formed in the systems containing lanthanum, cerium, and silver

X-ray phase and thermogravimetric analysis, scanning electron microscopy and energy-dispersion spectroscopy were used to study the products of phase formation during the precipitation of lanthanum and cerium salts in the presence of silver nitrate and recipients of precipitators, nucleating agents and hydrolysis regulators. Thermogravimetric analysis shows the completion of the La(OH)3 lattice dehydroxylation process at a temperature of ~ 300 °С and probable destruction of sulfates at a temperature of ~ 340 °С. The phase interaction of lanthanum oxide(III) with silver ends at T ~ 400 °C. The DTG curve shows a two-stage weight loss, which characterizes the destruction of lanthanum and silver hydroxides (250 °C) and the removal of sulfates (~ 340 °C), respectively. According to the TG, the total weight loss is 21.6 %. For the cerium-containing system the only endothermic effect of dehydroxylation of cerium hydroxide at T = 250 °C with its conversion into cerium dioxide is observed. The destruction of nitrates (anionic component of solutions) takes place at the temperature of 400 °C. Weight loss takes place at T = 150 °C and is 53.9 %. Thus, on the basis of TG-DTA data, it can be assumed that the formation of composites particles based on lanthanum and cerium oxides, modified with silver, ends at the temperature of 400 °C. The X-ray diffraction data shows that at the initial stage the system undergoes the formation of cerium and lanthanum hydroxides, and during lyophilization of the precipitate (T = 160 °C) the crystal lattice of hydroxides partial dehydroxylation takes place with the formation of trigonal oxides La2O3 and Ce2O3. It has been found that the presence of silver cations in the solution can affect the phase composition of lyophilized structures and the formation of the CeO2 phase. It is shown that the hydroxylamine chloride injection into the system can initiate the silver restoration on the lanthanum oxide surface and also partially restore it to the LaO phase. Temperature treatment of the samples (T = 400 °С) promotes homogenization of the precipitate composition: formation of 30 nm cerium dioxide particles with silver clusters evenly distributed on its surface, and hexagonal lanthanum oxide plates with individual silver particles as the second phase. In three-component systems, two modifications of lanthanum oxides (trigonal and cubic), cerium dioxide and metallic silver are formed. It is found that the chemical composition of the precipitates contains the main elements – La, Ce, O, Ag and impurity – S or Cl, as the anionic component of the initial solutions, N and K in the composition of the initial suspension. It is shown that the morphology of the samples is represented by hexagonal structures of lanthanum hydroxide and oxide, spherical and pseudocubic particles of cerium dioxide and lanthanum oxide, spherical clusters of silver.

Green Synthesis of Ceria Nanoparticles Using Azadirachta Indica Plant Extract: Characterization, Gas Sensing and Antibacterial Studies

In the present investigation we have fabricated the cerium dioxide (CeO2) nanoparticles by green route. While preparing the cerium dioxide nanoparticles by co-precipitation method, Neem leaf extract mixed into the precursor of cerium. The synthesized nanoparticles of CeO2 were used for the preparation of thick film sensor by using screen printing strategy. The fabricated CeO2 sensor was characterized by XRD, SEM, EDS and TEM techniques. The structural characteristics investigated by x-ray diffraction technique (XRD). XRD confirms the formation of cubic lattice of CeO2 material. The surface, texture, porosity characteristics were investigated from SEM analysis, while chemical composition of the material was analysed by EDS technique. The transmission electron microscopy (TEM) confirms the formation cubic lattice of the cerium dioxide material. The thickness of the films was calculated from mass difference method, the prepared film sensors belong to thick region. The fabricated material CeO2 sensor was applied as gas sensor to sense the gases such as LPG, petrol vapors (PV), toluene vapors (TV) and CO2. The CeO2 sensor showed excellent gas response for LPG and PV, nearly 93.20 % and 78.23 % gas response. The rapid response and recovery of the prepared sensors was observed at the tested gases. CeO2 material also employed for antibacterial study at several pathogenic organism such as pseudomonas, staphylococcus aureus and salmonella typhae. From antibacterial study it was observed that the material is capable of inhibiting the growth of these pathogenic microbes.

Antiviral Effect of Cerium Dioxide Nanoparticles on the Model of the Causative Agent of Bovine Viral Diarrhea

Cerium dioxide nanoparticles (CeO2) have a wide range of biological properties, including antiviral activity. Preparations based on cerium oxide nanoparticles can be effective against animal RNA viruses, which have the greatest epizootic significance for Ukraine and potentially against human viruses, including SARS-CoV-2. In our studies, we determined the effect of cerium dioxide nanoparticles on bovine viral diarrhea virus (BVDV), a pestivirus that is the etiological agent of bovine viral diarrhea. To determine the antiviral efficacy of CeO2, a cytopathogenic strain of BVDV “BK-1” was used as an etiological agent of bovine viral diarrhea, which induces a cytopathic effect on cow embryo lungs (CEL) cell culture. When evaluating the antiviral efficacy of CeO2, it was determined that the MPC for CEL cell culture is 0.057 μg/cm3, and the CC50 is 0.077 μg/cm3. The antiviral activity of CeO2 was evaluated by the IC50 index, which was 0.036 μg/cm3 and the selectivity index, which after co-administration of CeO2 with BVDV was 2.14. There was a decrease in the titer of infectious activity of the virus during treatment with CeO2 by 2.09 lg TCD50/cm3.

Synthesis, structure, and visible-light-driven activity of o-YbFeO3/h-YbFeO3/CeO2 photocatalysts

Photo-Fenton-like oxidation of organic substances is one of the key advanced oxidation processes based on the reversible Fe2+↔Fe3+ transition and the generation of a strong oxidant ·OH in the presence of H2O2 and is currently considered as a promising method for the purification of polluted aqueous media. However, the absence of effective and stable photocatalysts of this process, operating under the action of visible light, necessitates the exploratory studies, mainly among iron oxides and ferrites of various compositions and structures. In this work, using the method of solution combustion followed by heat treatment in air the heterojunction nanocomposites based on ytterbium orthoferrite and cerium dioxide of the composition o-YbFeO3/h-YbFeO3/CeO2 (0–20 mol.%) with high absorption in the visible region and advanced photo-Fenton-like activity were obtained. The nanocomposites were studied by EDS, SEM, XRD, BET, and DRS methods. The photo-Fenton-like activity of the nanocomposites was investigated during the degradation of methyl violet under the action of visible (λmax = 410 nm) radiation. As a result, the formation of I-type heterojunction based on stable rhombic (55.4–79.0 nm) and metastable hexagonal (19.5–24.0 nm) modifications of ytterbium orthoferrite (o-YbFeO3 and h-YbFeO3, respectively) and cubic cerium dioxide CeO2 (13.2–19.2 nm) nanocrystals was established. It was shown that the obtained nanocomposites had foamy morphology and were characterized by a specific surface in the range of 9.1–25.0 m2/g, depending on the CeO2 content. It was found that nanocrystalline components were chemically and phase-pure, uniformly spatially distributed over the nanocomposite, and had multiple contacts with each other. Based on this fact and the established electronic structure of the nanocomposite components, the formation of I-type heterojunction with the participation of o-YbFeO3 (Eg = 2.15 eV), h-YbFeO3 (Eg = 2.08 eV), and CeO2 (Eg = 2.38 eV) was shown, the presence of which increased photocatalytic activity of the resulting nanocomposite. The optimal content of CeO2 in the nanocomposite was 5%, and the o-YbFeO3/h-YbFeO3/CeO2–5% sample was characterized by the highest rate constant of photo-Fenton-like degradation of methyl violet under the action of visible light equal to k = 0.138 min–1, which was 2.5 to 5 times higher than for nanocomposites based on ytterbium orthoferrite. The obtained results obtained indicate that the developed nanocomposites can be considered as a promising basis for the advanced oxidation processes for the purification of aqueous media from organic pollutants.

Biological Synthesis of Metallic Nanoparticles from Different Plant Species

Green chemistry for the synthesis of different nanoparticles (NPs) from metal has become a new and promising field of research in nanotechnology in recent years. The inspire applications of metal oxide NPs have attracted the interest of researchers around the world. Various physical, chemical and biological methods in material science are being adapted to synthesize different types of NPs. Green synthesis has gained widespread attention as a sustainable, reliable, and eco-friendly protocol for biologically synthesizing a wide range of metallic NPs. Green synthesis has been proposed to reduce the use of hazardous compounds and as a state of a harsh reaction in the production of metallic NPs. Plants extract used for biosynthesis of NPs such as silver (Ag), cerium dioxide (C2O2), copper oxide (CuO), Gold (Au), titanium dioxide (TiO2), and zinc oxide (ZnO). This review article gives an overview of the plant-mediated biosynthesis of NPs that are eco-friendly and have less hazardous chemical effects.

On Placental Toxicology Studies and Cerium Dioxide Nanoparticles

The human placenta is a transient organ essential for pregnancy maintenance, fetal development and growth. It has several functions, including that of a selective barrier against pathogens and xenobiotics from maternal blood. However, some pollutants can accumulate in the placenta or pass through with possible repercussions on pregnancy outcomes. Cerium dioxide nanoparticles (CeO2 NPs), also termed nanoceria, are an emerging pollutant whose impact on pregnancy is starting to be defined. CeO2 NPs are already used in different fields for industrial and commercial applications and have even been proposed for some biomedical applications. Since 2010, nanoceria have been subject to priority monitoring by the Organization for Economic Co-operation and Development in order to assess their toxicity. This review aims to summarize the current methods and models used for toxicology studies on the placental barrier, from the basic ones to the very latest, as well as to overview the most recent knowledge of the impact of CeO2 NPs on human health, and more specifically during the sensitive window of pregnancy. Further research is needed to highlight the relationship between environmental exposure to CeO2 and placental dysfunction with its implications for pregnancy outcome.

Synthesis and Photocatalytic Degradation of Water to Produce Hydrogen from Novel Cerium Dioxide and Silver-Doped Cerium Dioxide Fiber Membranes by the Electrospinning Method

The sol-gel method combined with the electrospinning technique were used to synthesize CeO2 nanofiber membranes and CeO2 fiber membranes doped with different contents of nano-silver. The thermal degradation behavior, phase structure, morphology, and optical and photocatalytic hydrogen production efficiency of CeO2 nanofiber membranes and CeO2 fiber membranes doped with different contents of nano-silver were studied. X-ray diffraction (XRD) results indicate that the increase of silver concentration can inhibit the formation of CeO2 crystal. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations show that in the prepared CeO2 with a diameter of about 100 nm and fiber membrane material doped with nano-silver, the fiber is made of a large number of accumulating grains. Analysis of optical properties found that the doped nano–silver CeO2 fiber membranes enhance the absorption of visible light and reduce the band gap of the material. Photocatalytic experiments show that the cerium dioxide nanofibers doped with nano-silver can greatly improve the photocatalytic performance of materials than that of pure CeO2. The Ag/CeO2 fiber membrane with the Ag/CeO2 molar ratio of 3:50 possesses the highest photocatalytic hydrogen production efficiency because of its high electron hole transfer and separation efficiency. This novel synthesis strategy can be used to prepare other broad band gap semiconductor oxides and enhance their photocatalytic activity.

Characterization of size and morphological composition of ablated nanoparticles of cerium dioxide after ultrasonic dispersion and centrifugation in aqueous solution

The paper investigates the size and morphological composition of ablated cerium dioxide nanoparticles after ultrasonic dispersion at centrifugation speeds from 800 to 13400 rpm. A nanodispersed solution of cerium dioxide was deposited onto silicon substrates by the drop method. To characterize the size and morphological composition of cerium dioxide nanoparticles, methods of scanning electron and atomic microscopy were used, and X-ray phase analysis was performed. It was found that ablated cerium dioxide particles in an aqueous solution agglomerated and without centrifugation their average size was 162 nm, after centrifugation their average size varied from 86 nm to 142.5 nm. X-ray phase analysis showed that with an increase in the centrifuge speed, the size of the coherent scattering region decreases, which affects the effectiveness of antioxidant properties, for example, in the Fenton reaction.