Introduction. The use of digital technologies will increase the efficiency of animal husbandry. These technologies include optical monitoring of product quality. The aim of the research is to study ...the dependence of the spectral characteristics and parameters of excitation and luminescence of milk during souring.
Materials and Methods. The milk with a fat content of 3.2% was used for measurements. The acidity was controlled by the titrimetric method. The excitation and luminescence registration spectra were measured on a Fluorat-02-Panorama spectrofluorimeter in the range of 200–500 nm. Spectra parameters were calculated in the PanoramaPro and Microcal Origin programs.
Results. When milk sours, excitation spectra shift downwards, while a qualitative change in characteristics is observed with the range of 350–500 nm, although the photoelectric signal absolute level is almost an order of magnitude less than with a range of 220?340 nm. The photoluminescence flux when excited by the radiation with wavelength of 262 nm decreases during the souring process. The flux excited by the radiation with wavelength of 385 nm increases especially in the first three days. The flux at wavelength of 442 nm decreases slightly. Statistical parameters and energy of photoluminescence spectra are not informative for the milk souring control. The dependence of the ratio of photoluminescence fluxes excited by the radiation of 385 and 442 nm on acidity is linearly approximated with a determination coefficient of 0.99.
Discussion and Conclusion. The change in the milk luminescent properties can be used as a marker of its souring with acidity control. To create a method for monitoring milk quality indicators during souring, the most informative is the use of excitation wavelengths of 385 and 442 nm with subsequent registration of photoluminescence in the ranges 440–490 and 490–600 nm respectively.
Landing problems of light freight aircraft on account of spontaneous deployment of braking flaps are analyzed. Types of asymmetric deployment are considered. Recommendations are made for pilot ...responses in such situations.
Single nucleotide substitutions in gene sequence associated with conformational changes in protein receptor or in expression of interferon receptors may explain variations in human susceptibility to ...infection and severity of COVID-19 along with other well-known risk factors. The study aimed to investigate associations between polymorphic variants of interferon receptor genes, COVID-19 severity and prevalence of antibiotic resistance genes in the gut microbiota. Materials and methods. The study was conducted using a random sample of Arkhangelsk population aged 42 to 76 years (n = 305). The research involved gathering COVID-19 data from the Federal Register, conducting blood tests for SARS-CoV-2 antibodies and polymorphic interferon receptor gene variants, and identifying antibiotic resistance genes in stool samples. Results. During the first 12–15 months of the COVID-19 pandemic, 17.4% of the study participants had symptomatic COVID-19, while 32.8% were asymptomatic. By the Autumn of 2022, symptomatic COVID-19 cases rose up to 36.4%, while asymptomatic cases increased to 61.3%. We reveal an association between the CC genotype of the IFNAR1 gene rs2257167 variant, the presence of the T allele of IFNAR2 gene rs2229207 variant, the CCTT haplotype and symptomatic COVID-19. The GCTC haplotype was associated with pneumonia and COVID-19 severity. In November 2022, macrolide resistance genes were observed in 98.4% of cases, whereas those to beta-lactams and glycopeptides — in 26.9% and 13.8% cases, respectively. Resistance to three classes of antibiotics was observed in 4.9% and was more frequently detected in individuals with the ССТТ haplotype. Genes encoding beta-lactamases were more often found in individuals with the GCTC haplotype, those who had COVID-19 with pneumonia and those who received hospital treatment. Glycopeptide resistance genes were associated with the CC genotype of the rs2257167 variant of IFNAR1 gene. Conclusion. We identified genetic determinants of susceptibility, symptomatic infection and COVID-19 severity. The associations between polymorphic variants of interferon receptor genes and COVID-19 severity can be used to identify people with a genetic predisposition to severe infection and to determine priority groups for vaccination, including the prevention of antibiotic resistance in complicated course of viral infections.
This paper presents the results of experimental and numerical investigation of the influence of dust nanoparticles on glow discharge plasma properties. A special apparatus was developed to provide a ...steady input of dust nanoparticles into ac glow discharge plasma. The plasma was created in a large-volume coaxial gridded hollow cathode. A novel simulation approach of dusty plasma was developed specifically for the experimental conditions. An extended fluid approach with drift-diffusion approximation for the electron and ion fluxes was modified to account for charged dust nanoparticles' contribution to net charge and for ion and electron loss on the surface of particles. Uniform distribution of dust particles in plasma and instantaneous charging process were assumed during simulations. Experimental measurements were carried out using Langmuir probe. Simulations and probe measurements were carried out before and after input of dust particles into plasma. Under the conditions studied both methods showed a decrease by a factor of 5 in electron density caused by input of dust nanoparticles.
The paper considers a new digamma distribution generalizing the distributions from the gamma and beta classes. The presentation of the digamma distribution as a fractional-scale mixture of gamma ...distributions is proved. Explicit forms of the moments and density of the considered distribution are given. A method for statistical estimation of unknown parameters based on logarithmic cumulants is described. A number of numerical examples of estimating concentration parameters from model samples are given.
The formation of photoluminescent porous silicon (PSi) nanoparticles (NPs) is usually based on an expensive semiconductor grade wafers technology. Here, we report a low-cost method of PSi NPs ...synthesis from the industrial silicon waste remained after the wafer production. The proposed method is based on metal-assisted wet-chemical etching (MACE) of the silicon surface of cm-sized metallurgical grade silicon stones which leads to a nanostructuring of the surface due to an anisotropic etching, with subsequent ultrasound fracturing in water. The obtained PSi NPs exhibit bright red room temperature photoluminescence (PL) and demonstrate similar microstructure and physical characteristics in comparison with the nanoparticles synthesized from semiconductor grade Si wafers. PSi NPs prepared from metallurgical grade silicon stones, similar to silicon NPs synthesized from high purity silicon wafer, show low toxicity to biological objects that open the possibility of using such type of NPs in nanomedicine.
—The study of molecular and genetic mechanisms of sex determination in the poplar is of interest not only in the fundamental science, but also in the applied research. In landscaping of large ...settlements, it is advisable to use male individuals of the
Populus
genus due to their hypoallergenicity and increased resistance to environmental pollution, stress conditions, and pathogens. However, sex determination in poplars is complicated by the complex genetic structure of the sex-determining region of the genome (SDR). In this review, the emergence, evolution, structure, and function of the SDR in the genus
Populus
are discussed. Current insights into the structure and function of the key regulator of sex selection in poplars, orthologue of the
ARR16
/
ARR17
gene and the possible roles of other genes that are differentially expressed between male and female plants, including microRNAs, in this process are discussed in detail. The great diversity of species and the high complexity of SDR organization justify the need for further study of the molecular mechanisms of sex determination in poplars.
The problem of designing unique building structures in terms of predicting the climatic characteristics of premises is considered. These facilities include the Surfing Center, which is planned to be ...built in Moscow. An integral part of the design work is the determination of indoor humidity and the selection of parameters for climate control systems. Within the framework of solving this problem, a technique is developed for modeling the rate of evaporation from the surface of a swimming pool (pool) during active waves. The technique is based on the use of computational fluid dynamics methods in combination with the calibration of the empirical constants of the models according to the known experimental data for the evaporation rate in still water. According to the revised method, a correction factor to the formula of the VDI2089 standard is determined to estimate the rate of evaporation from the surface of the pool for the given wave parameters.
It is demonstrated for the first time that the presence of a small number of fast, nonlocal electrons can dramatically change the thickness of and electric field in the near-wall sheath. Even if the ...density of the nonlocal fast group, , is much less than the density of the bulk electrons, n(b) (n(f) approximately 10(-5) n(b)), the near-wall potential can increase dramatically resulting in a comparable increase in the sheath thickness. Because of this low fractional density, the average energy (electron temperature ) of all electrons is little changed from that of the bulk, yet the near-wall potential drop can increase to tens of T(e)/e. More importantly, due to the nonlocal nature of this group of electrons, the near-wall sheath potential is found to be independent of and is determined only by the energy of the fast group.
