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The article presents the results of the spectral dependence study of the quantum efficiency of photocatalytic water decomposition. The relationship between the radiation spectrum and the efficiency of photocatalytic water decomposition into hydrogen and oxygen is determined. For this purpose, an electrolyte based on sodium nitrate is studied. The photocathode contained nanoporous silver layers. It is shown that the maximum quantum efficiency of photocatalytic water decomposition by spectrum integrally amounts to 1.9 %, and increases with decreasing radiation wavelength. The obtained results can be used in the development of solar energy devices designed for photocatalytic water decomposition into hydrogen and oxygen.

Abstract Background Mycoplasma pneumoniae is a major cause of community-acquired pneumonia (CAP) in school-aged children. Macrolides are the first-line treatment for this infection. However, it is unclear whether macrolides are effective in treating M. pneumoniae CAP, mainly due to limitations in microbiological diagnosis of previous studies. The extensive global use of macrolides has led to increasing antimicrobial resistance. The overall objective of this trial is to produce efficacy data for macrolide treatment in children with M. pneumoniae CAP. Methods The MYTHIC Study is a randomized, double-blind, placebo-controlled, multicenter, non-inferiority trial in 13 Swiss pediatric centers. Previously healthy ambulatory and hospitalized children aged 3–17 years with clinically diagnosed CAP will be screened with a sensitive and commercially available M. pneumoniae-specific IgM lateral flow assay from capillary blood. Mycoplasma pneumoniae infection in screened patients will be verified retrospectively by respiratory PCR (reference test) and IgM antibody-secreting cell enzyme-linked immunospot (ELISpot) assay (confirmatory test for distinguishing between carriage and infection). Patients will be randomized 1:1 to receive a 5-day treatment of macrolides (azithromycin) or placebo. The co-primary endpoints are (1) time to normalization of all vital signs, including body temperature, respiratory rate, heart rate, and saturation of peripheral oxygen (efficacy), and (2) CAP-related change in patient care status (i.e., admission, re-admission, or intensive care unit transfer) within 28 days (safety). Secondary outcomes include adverse events (AEs), as well as antimicrobial and anti-inflammatory effects. For both co-primary endpoints, we aim to show non-inferiority of placebo compared to macrolide treatment. We expect no macrolide effect (hazard ratio of 1, absolute risk difference of 0) and set the corresponding non-inferiority margins to 0.7 and −7.5%. The “at least one” success criterion is used to handle multiplicity with the two co-primary endpoints. With a power of 80% to reject at least one null hypothesis at a one-sided significance level of 1.25%, 376 patients will be required. Discussion This trial will produce efficacy data for macrolide treatment in children with M. pneumoniae CAP that might help to reduce the prescription of antibiotics and therefore contribute to the global efforts toward reducing antimicrobial resistance. Trial registration ClinicalTrials.gov, NCT06325293. Registered on 24 April 2024

The experience of technological development of our country is an important source of ideas and approaches to the further development of agriculture based on domestic equipment and technologies. The study of its evolution necessitates the using of periodization. It is currently undeveloped for chemization of agriculture, more often being replaced by a set of key dates and biographies. So, it is nesessary to develop a holistic version of the structuring of chemization history. (Research purpose) To propose and substantiate the authors’ version of Russian agriculture chemization periodization. (Materials and methods) Monographs, legal acts, collected works and publications of outstanding scientists were studied using chronological, genetic and periodization methods of historical research (Results and discussion) The proposed periodization integrates previous historical ideas and hypotheses. The chemization of Russian agriculture has more than 250 years of history, which can be divided into 6 stages: preparatory (prehistory of chemization, which has three sub-stages), formative, extensive, stabilization, intensive and decentralized. The starting point is a publication of work «On lands fertilization» by A.T. Bolotov in 1770. Currently, the prerequisites for a new stage in the development of chemization are being formed, and it main attributes are digitalization, mechanization and biologization in the highest degree. (Conclusions) The proposed approach to structuring the history of Russian agriculture chemization is useful both for researchers and for training organization. The presence of clear guidelines increases the effectiveness of studying the historical aspects of agriculture, science and technology, which are so necessary for the professional and personal development of future agronomists and engineers.

We study the evolution of the friendship index in complex social networks over time. The elements of the networks are the users, and the connections correspond to the interactions between them. The friendship index of a node is defined as the ratio of the average degree of its neighbors to the degree of the node itself. Obviously, in the process of network growth, the value of the friendship index for any node in the network may change due to the fact that new edges can be attached to this node or its neighbors. In this paper, we study the dynamics of the friendship index of a single node over time for growth networks generated on the basis of the preferential attachment mechanism. We find both the asymptotics of their expected values and the variances over time. In addition, we analyze the behavior of the friendship index for five real networks.

The number of patients with autoimmune thyroid diseases (Graves’disease, Hashimoto’sthyroiditis) is increasing globally. The most important part in the diagnosis of Graves’ disease (GD) is the detection of autoantibodies to the thyrotropin receptor (TSHR) in Graves’ patients’ sera. For the differential diagnosis of antibodies to thyroid antigens, it is promising to use tests based on monoclonal antibodies to TSHR, which can be obtained not only as a result of immunization with native or recombinant TSHR protein, but also through DNA immunization with genetically engineered constructs containing fragments of the TSHR gene. Based on mRNA we isolated from the thyroid tissue in GD, a number of fragments of the thyrotropin receptor gene were cloned, suitable for DNA immunization of animals. The purpose of this work is to evaluate the immunogenic properties of one of the constructed vectors, pVAX1-TSHR (1160), in a mouse model. The successful inclusion of the extracellular domain gene fragment of the human TSHR (1160), which was transfected into CHO cells as a part of the pVAX1 vector was confirmed by immunoblotting and ELISA. The immune response formed to the injection of the pVAX1 vector into BALB/c mice, containing a fragment of the human TSHR gene, was detected in different versions of ELISA. Immunization of animals with the DNA vector pVAX1-TSHR according to an experimentally selected scheme was effective for the formation of mouse splenocytes, secreting antibodies to TSHR, which were used for successful hybridization. This was confirmed by the results of determining antibody production to TSHR in murine blood sera. The level of antibody production remained high (titer more than 1:10.000) at the 8th week of the experiment. As a result of selection of individual clones according to the criteria of proliferative activity and stability of antibody production, the most stable cultures secreting mAbs against TSHR were selected.

Background: The important challenge to the biotechnology is to find new effective fusion partners that enable to improve solubility, expression, and optimize the subsequent fine purification of the target protein. Results: The most invariant part of the most immunogenic region of the surface virulence factor A of Streptococcus pneumoniae was selected as a model target protein, while the thermostable chemotaxis polypeptide of W-type from Thermotoga petrophila was used as a fusion partner. The genes encoding fusion variants of these proteins were constructed and cloned into a plasmid vector under the control of the strong bacteriophage T7 transcription regulatory system. Effective Escherichia coli producer strains were obtained, and optimal conditions were chosen for the production of resulting constructs. The optimal pH and temperature ranges of recombinant proteins were determined, and three-dimensional shapes of their molecules were also predicted. Methods of low-stage protein purification were improved. Some of the isolated proteins demonstrated a high level of expression, solubility and purity. Conclusions: Novel chimeric proteins were obtained which had not previously been observed in nature in such domain combinations. It was shown that the biotechnologically valuable characteristics of the hybrid proteins were more marked when the thermal-resistant partner was combined with the N-terminus of pneumococcal protein. The principles of their low-stage purification were performed which does not require any special equipment. That is a basis for significant reduction of prices for diagnostic test-systems components and subunit vaccine production.How to cite: Grishin DV, Sidorov NG, Parfenova OK, et al. Construction, heterological expression and a simple purification of the BP region of the pneumococcal surface protein a fused in different orientations to the chemotaxis adaptor protein CheW from Thermotoga petrophila. Electron J Biotechnol 2024;71. https://doi.org/10.1016/j.ejbt.2024.05.001.

Introduction. The paper proposes a method of accounting for energy dissipation for the Timoshenko beam by constructing a damping matrix based on a modified Rayleigh function in the numerical solution of the problem. In this modification, the velocity of displacements is replaced by the velocities of linear and angular deformations. This approach allows us to take into account energy dissipation due to internal friction in the material when both its volume and shape change. The presented technique is promising in practical calculations of structures when shear stiffness has a significant impact on their stress-strain state.Materials and methods. Several proven methods of energy dissipation accounting are considered, including those that make it possible to take into account the energy loss of a moving structure during friction with the external environment (external damping) and dissipation due to friction in the material of the structure deformed in motion (internal damping). Methods for determining the damping coefficients for each of them are presented. The finite element method is used to calculate rod systems. Damping matrices are derived from the condition of stationarity of the total energy of deformation of a mechanical system in motion, including linear and angular deformation rates.Results. Damping matrices proportional to strain rates obtained on the basis of the modified dissipative Rayleigh function are given. A method for determining the damping coefficient taking into account the rates of angular deformation is proposed.Conclusions. The damping matrices presented in the paper describe the energy dissipation during vibrations of mechanical systems due to internal friction in the material. The internal damping matrix was obtained taking into account the influence of linear and angular deformation rates to simulate the dynamic behaviour of short bending structural elements, the deformation of which is described using the Timoshenko model. The performed dimensional check additionally confirms the correctness of the damping matrix construction. Moreover, the dimension of the proposed shear damping coefficient is the same as that of the widely used viscosity coefficient.

When large-sized oil pipelines are subjected to skin effect heating under the constraint of limited current, the power supply converter must provide a higher current frequency. However, an inappropriate frequency can lead to increased energy losses and consequently reduce heating efficiency. To achieve higher heating efficiency of large-sized pipelines, this paper proposes a temperature control strategy based on optimal frequency forecast. First, a skin effect heating model is established to illustrate the necessity of frequency forecasting. Then, using the small sample data from the oil field, an optimal frequency forecasting method based on Gradient Boosting Decision Tree (GBDT) is proposed. At the forecasted frequency, a dual closed-loop control strategy for current and temperature, based on a designed three-phase converter, is employed to achieve temperature control under limited current conditions. The feasibility and effectiveness of this approach are demonstrated through a case study involving a 159 mm oil pipeline with a heating current of less than 80A. The experiment shows that with the forecasted frequency, the pipeline temperature reached 40 °C within 14 min, and the energy consumption per unit length of the pipeline is 394 W/m, complying with the standard Q/SY 06022-2016.