Search

We investigated the chemical beam epitaxy of GaP 1 − x N x grown on nominally (001) -oriented Si substrates, as desired for the lattice-matched integration of optoelectronic devices with the standard Si technology. The growth mode and the chemical, morphological, and structural properties of samples prepared using different growth temperatures and N precursor fluxes were analyzed by several techniques. Our results show that, up to x ≈ 0.04 , it is possible to synthesize smooth and chemically homogeneous GaP 1 − x N x layers with a high structural quality. As the flux of the N precursor is increased at a given temperature to enhance N incorporation, the quality of the layers degrades upon exceeding a temperature-dependent threshold; above this threshold, the growing layer experiences a growth mode transition from 2D to 3D after reaching a critical thickness of a few nm. Following that transition, the morphology and the chemical composition become modulated along the [ 110 ] direction with a period of several tens of nm. The surface morphology is then characterized by the formation of { 113 } -faceted wires, while the N concentration is enhanced at the troughs formed in between adjacent (113) and (1 ¯ 1 ¯ 3). On the basis of this study, we conclude on the feasibility of fabricating homogeneous thick GaP 1 − x N x layers lattice matched to Si (x = 0.021) or even with N content up to x = 0.04. The possibility of exceeding a N mole fraction of 0.04 without inducing coupled morphological–compositional modulations has also been demonstrated when the layer thickness is kept below the critical value for the 2D–3D growth mode transition. [ABSTRACT FROM AUTHOR]

The article describes the effect of probiotic strains Lacticaseibacillus rhamnosus AG16, Limosilactobacillus fermentum HFD1, and Lactiplantibacillus plantarum LS-4.4 on the meat quality of quail. The strains were grown on a whey-based nutrient medium, and in the form of suspension were introduced into the diet of birds for two months. The use of these feed additives, especially L. fermentum HFD1, resulted in a decrease in the pH of the quail breast meat. All tested strains induced a decrease in water holding capacity and cooking loss of quail breast meat compared to the control variant. The meat of quail fed with probiotic lactobacilli was less stiff, that resulted in less chewing effort in the raw meat and less cutting effort in the cooked meat.

In connection with the active development of the poultry industry in the world, the pressing issue is to obtain environmentally friendly livestock products. Such preparations that can provide such products are the newest probiotics, obtained on the basis of representatives of normal comormal microorganisms lacto- and bifidobacteria. These types of microorganisms have antibacterial and immunomodulating properties. The effectiveness of probiotics has long been proven, but these drugs have not been widely used. Therefore, the purpose of this work was to characterize probiotic drugs and their use in poultry on the basis of existing literary sources. Bacteria that make up probiotics, produce antibodies to protect the body and stimulate the immune response to the pathogen, prevent pathogenic microorganisms from attaching to the intestinal walls, and also inhibit their growth. In addition, probiotics strengthen the intestinal mucous layer, which is a barrier to infection, block the synthesis of toxic compounds by pathogenic flora and contribute to their destruction. Also, the benefit of probiotics is the ability of beneficial bacteria to synthesize vitamins B and K. As a result, the process of splitting substances from food improves, digestion is normalized, toxic elements are neutralized and the growth of pathogenic flora is suppressed. Today, the normal microflora is a qualitative and quantitative ratio of the associations of microorganisms of individual organs and systems that maintain the biochemical, metabolic and immune balance of the host organism, necessary to maintain its health. It is an important factor in the overall homeostasis of the macroorganism. A change in the balance of the intestinal microflora is called dysbacteriosis, which can be caused by the use of antibiotics and other stressful factors. Today, international organizations (FAO/WHO) put forward stringent requirements for the evaluation of probiotic strains and drugs based on them, including: the precise identification of microorganisms using microbiological and genetic methods of investigation, a comprehensive description of biological activity and safety, and obtaining evidence of the clinical efficacy of probiotics. The biological effectiveness of probiotic drugs is determined not only by the properties of the strains used, but also by the technologies of their production, where the main goal is to achieve the maximum yield of viable cells of bacteria and biologically active substances synthesized by them, useful for the macroorganism. Microflora of the digestive tract of birds. Birds differ from other agricultural animals by the structure of the digestive system, high metabolic rate, the important role played by enzymes of microflora of the gastrointestinal tract. Chickens are more susceptible to infections, adverse environmental factors than mammals, since they do not receive immunostimulants and nutrients with maternal milk. The death of the young bird is largely due to the disease and disruption of the gastrointestinal tract, caused by pathogenic and conditionally pathogenic microorganisms. In the conditions of industrial livestock and poultry farming, the most economically advantageous is the use of drugs based on substances of natural origin, have an effective antagonistic effect on pathogens of infectious diseases and the ability to positively influence the immune response, that is, act as immunostimulants. These drugs are the latest probiotics derived from the representatives of normal commensal microflora lactobacterium and bifidobacteria, as well as bacilli, which are part of a generation of self-limiting antagonists. Preparations based on the above microorganisms exhibit antibacterial and immunomodulating properties. Thus, probiotics are promising drugs for the treatment of various dysbiotic conditions and infectious diseases.

Compact laboratory neutron sources play a crucial role in both fundamental physical research and practical applications, such as neutron radiography and spectroscopy. One of the most promising strategies to develop such a source is the use of laser-plasma accelerators of electrons or ions and the subsequent initiation of nuclear reactions (γ,n), (p,n), or (d,n) with the release of neutrons. In this study, we propose a neutron source based on (γ,n) photodisintegration reactions and characterize it using an electron beam from a 1‑TW laser-plasma accelerator. The maximum neutron flux reaches ~105 neutrons/s srad at a laser-radiation efficiency of ~106 neutrons/J. While maintaining efficiency and increasing the energy of the laser pulse by a factor of 10, the neutron flux becomes sufficient for several applications. To investigate neutron production using electron beam parameters measured in experiments, we conduct numerical Monte Carlo simulations. Recording the number of neutrons generated in an experiment can be used to estimate the charge and average energy of accelerated electrons. The simulation results show good agreement with values measured by standard beam-diagnostic tools, confirming the accuracy of our approach. [ABSTRACT FROM AUTHOR]