This paper presents the history of the development of heterojunction silicon solar cells from the first studies of the amorphous silicon/crystalline silicon junction to the creation of HJT solar cells with novel structure and contact grid designs. In addition to explanation of the current advances in the field of research of this type of solar cells, the purpose of this paper is to show possible ways to improve the structure of the amorphous silicon/crystalline silicon-based solar cells for further improvement of the optical and electrical parameters of the devices by using of numerical simulation method and current hypotheses. This paper briefly describes the history, beginning from the first studies of and research of HJT-structure solar cells. It raises questions about the advantages and existing problems of optimization of HJT solar cells. The authors of this paper are proposing further ways of design development of HJT solar cells. © 2023 by the authors.

The article analyzes approaches to the use of cloud technologies in the process of teaching students at large universities. The model of the academic cloud of a modern university is considered. Examples of software and functional platforms that meet the needs of students in electronic learning resources are given. The deployment models of the cloud-oriented educational environment that includes private cloud infrastructure as a service (IaaS) and platform as a university service are analyzed. The cost of deploying an academic cloud based on the educational institution's infrastructure and renting infrastructure from a vendor is compared. A multifactorial model for evaluating investment options in the university cloud in the context of fuzzy information is proposed. In contrast to the known approaches to solving such a problem, our model assumes that the dynamics of the financial states of the players are set through a system of discrete equations. These equations describe the dynamics of multidimensional variables. The latter made it possible to consider the general problem of investing in the academic cloud within the framework of a game scheme for tasks in a fuzzy formulation, with the financial resources (FR) available to the educational institution. Preference sets and optimal financial allocation strategies for building an academic cloud are found. © 2024 This is an open access article under the CC BY-SA license

This study aims to synthesize and characterize a fumarate-Al-based Metal-Organic Framework (Al-Fum MOF) to evaluate its adsorption properties towards two organic dyes, namely: Indigo Carmine (IC) and Orange II (OII). The Al-Fum MOF was synthesized by a non-solvothermal method and characterized by XRD, FTIR, EDX, TGA, N2 sorption and pHPZC. The results of this work show that the pseudo-second-order model better describes the adsorption process for both dyes. The plausible mechanisms reveal a duality between the physisorption phenomenon and physicochemical interactions, the latter being predominant. The optimal conditions for adsorption were determined using centered composite experimental designs, resulting in error percentages below 2 %: for IC (pH 3, concentration of 84.7 mg/L and adsorbent mass of 25 mg) and for OII (pH 3, concentration of 100 mg/L and adsorbent mass of 25 g). The adsorbed amounts were 33.8 and 22.9 mg/g for IC and OII, respectively. The regeneration of Al-Fum MOF was studied and the results suggest that the material can remain active during several use cycles. This study contributes to the advancement of knowledge on adsorbent materials for wastewater treatment and highlights the potential of Al-Fum MOF for practical applications. However, further studies are needed to evaluate the application of Al-Fum MOF to real and complex wastewater. © 2025 The Author(s)

The article presents an innovative approach to the restoration and stabilization of weak soils, using the example of the Turkestan region, characterized by an arid climate and degraded soil cover. The main goal of the study was to develop and experimentally validate a biostabilization technology aimed at improving the physico-chemical and engineering-geological properties of soils through environmentally safe compositions. This technology addresses challenges such as erosion, low bearing capacity, and land degradation, which are especially critical in arid regions. The research involved an engineering-geological analysis of soils using laboratory and computational methods. Evaluated parameters included humus content, mobile phosphorus, nitrogen, exchangeable bases, water retention, and resistance to erosion. Experimental results showed that vermicompost significantly improves soil structure and geotechnical stability. Potassium polyacrylamide enhances water retention, reducing the risk of deformation and settlement. Lime-sulfur broth strengthens surface horizons and reduces wind erosion, although its impact on mechanical properties requires further study. The proposed biostabilization methods effectively improve the geotechnical characteristics of weak soils, increasing their resistance to erosion and enhancing their suitability for engineering applications such as foundation stabilization, slope reinforcement, and land restoration. These technologies are especially relevant in arid climates, where soil degradation is widespread. The study's findings can be applied in geotechnical engineering, engineering geology, and sustainable agriculture to support environmentally responsible land use and the restoration of degraded areas.

The main reserves of fresh groundwater in South Kazakhstan are confined to aquifers of Quaternary, Neogene, Paleogene, Cretaceous deposits of Artesian basins. They play a major role in the water supply of the population with drinking water, especially large water consumers. Fractured water basins are characterized by significantly smaller reserves of fresh groundwater, but their widespread distribution in the region is of practical interest for the water supply of smaller water consumers. The anthropogenic impact on groundwater has become especially noticeable in the current century due to the development and intensification of industry and agriculture, the growth of large cities and the expansion of urbanized territories. Intensification of the anthropogenic load on the resource potential of groundwater and associated ecosystems leads to a progressive deterioration of ecological and hydrogeological conditions in South Kazakhstan. This is primarily due to the depletion of groundwater resources, the formation of depression craters and water retention zones, groundwater pollution, which significantly affects the natural environment and human habitat. These negative changes occur especially intensively in areas of mining, oil and gas production and chemical industry development, characterized by significant changes in the existing water exchange, which is caused by violations of the water balance in the subsurface caused by the drainage of mineral deposits during their extraction, the exploitation of groundwater for domestic and industrial water supply and drainage systems, and also presence of industrial and household untreated effluents. © 2022, National Academy of Sciences of the Republic of Kazakhstan. All rights reserved.

L-asparaginase (L-ASP) is one of the key enzymes used in therapeutic applications, particularly to treat Acute Lymphocytic Leukemia (ALL). L-asparagine is a non-essential amino acid, which means that it can be synthesized by the body and is not required to be obtained through the diet. The synthesis of L-asparagine occurs primarily in the liver, but it also takes place in other tissues throughout the body. In contrast, leukemic cells cannot synthesize L-asparagine due the absence of L-asparagine synthetase and should obtain it from circulating sources for protein synthesis and cell division processes to ensure their vital functions. L-ASP catalyzes the deamination process of L-asparagine amino-acid into aspartic acid and ammonia, depriving leukemic cells of asparagine. This leads to decreased protein synthesis and cell division in tumor cells. However, using L-ASP has side effects, such as hypersensitivity or allergic reaction, antigenicity, short half-life, temporary blood clearance, and toxicity. L-ASP immobilization can minimize the side effects of L-ASP by stopping the immune system from attacking non-human enzymes and improving the enzyme's performance. The first strategy includes modification of enzyme structure, such as covalent binding (conjugation), adsorption to the support material and cross-linking of the enzyme. The chemical modification of residues, often nonspecific, changes the enzyme's hydrophobicity and surface charge, lowering the enzyme's activity. Also, the first strategy exposes the enzyme's surface to the environment. This eliminates its performance and does not allow targeted delivery of the enzyme. The second strategy is based on the entrapment of the enzyme inside the protecting structure or encapsulation. This strategy offers the same benefits as the first. Still, it also enables reducing toxicity, prolonging in vivo half-life, enhancing stability and activity, enables a targeted delivery and controlled release of the enzyme. Compared to the first strategy, encapsulation does not modify the chemical structure of the enzyme since L-ASP is only effective against leukemia in its native tetrameric form. This review aims to present state of the art in L-ASP formulations developed for reducing the side effects of L-ASP, focusing on describing improvements in their safety. The primary focus in the field remains to be improving the overall performance of the L-ASP formulations. Almost all encapsulation systems allow reducing immune response due to screening the enzyme from antibodies and prolonging its half-life. However, the enzyme's activity and stability depend on the encapsulation system type. Therefore, the selection of the right encapsulation system is crucial in therapy due to its effect on the performance parameters of the L-ASP. Biodegradable and biocompatible materials, such as chitosan, alginate and liposomes, mainly attract the researcher's interest in enzyme encapsulation. The research trends are also moving towards developing formulations with targeted delivery and increased selectivity. © 2023

The increase in industrialization has led to an exponential increase in heavy metal (HM) soil contamination, which poses a serious threat to public health and ecosystem stability. This review emphasizes the urgent need to develop innovative technologies for the environmental remediation of intensive anthropogenic pollution. Phytoremediation is a sustainable and cost-effective approach for the detoxification of contaminated soils using various plant species. This review discusses in detail the basic principles of phytoremediation and emphasizes its ecological advantages over other methods for cleaning contaminated areas and its technical viability. Much attention has been given to the selection of hyperaccumulator plants for phytoremediation that can grow on heavy metal-contaminated soils, and the biochemical mechanisms that allow these plants to isolate, detoxify, and accumulate heavy metals are discussed in detail. The novelty of our study lies in reviewing the mechanisms of plant–microorganism interactions that greatly enhance the efficiency of phytoremediation as well as in discussing genetic modifications that could revolutionize the cleanup of contaminated soils. Moreover, this manuscript discusses potential applications of phytoremediation beyond soil detoxification, including its role in bioenergy production and biodiversity restoration in degraded habitats. This review concludes by listing the serious problems that result from anthropogenic environmental pollution that future generations still need to overcome and suggests promising research directions in which the integration of nano- and biotechnology will play an important role in enhancing the effectiveness of phytoremediation. These contributions are critical for environmental scientists, policy makers, and practitioners seeking to utilize phytoremediation to maintain the ecological stability of the environment and its restoration. © 2024 by the authors.

Hexavalent chromium Cr (VI) compounds present in ilmenite concentrate not only pose significant environmental hazards due to their toxicity but also complicate further processing, interfering with technological operations in industrial production. The high chromium content in ilmenite concentrates hinders their conversion into titanium-containing slag, necessitating the removal of chromium ions to permissible residual levels to produce titanium dioxide. In this study, various sorbents were investigated for the removal of chromate ions from the industrial effluents generated during ilmenite concentrate processing. The sorbents examined included natural and modified diatomite, activated carbon, taurite (shungite), and the ion-exchange resin Lewatit M500. The structures of both natural and modified diatomite were analyzed using scanning electron microscopy (SEM). It was determined that natural diatomite samples consist of diatom frustules of various shapes and their fragments, with structural element sizes ranging from submicron dimensions to 50 µm. A mathematical analysis of the sorption data for hexavalent chromium ion removal from solutions was performed. The results demonstrated high sorption efficiencies for Lewatit M500 (98.34%) and diatomite modified with iron compounds (98.95%). The findings suggest that diatomite is a promising sorbent for chromate ion removal from wastewater due to its availability and potential for chemical modification.

The protection of metallic structures against corrosion remains a pivotal challenge across numerous industries. In recent years, the amalgamation of modified bitumen with epoxy resin has emerged as a promising avenue in the pursuit of enhanced corrosion protection. This novel composite material showcases exceptional potential in thwarting the deleterious effects of corrosion, offering an innovative solution to safeguard vital infrastructure, industrial components, and diverse metallic substrates. The synergistic properties stemming from the combination of modified bitumen and epoxy resin present an intriguing prospect for superior durability, chemical resistance, and structural integrity, thereby fostering advancements in the realm of anti-corrosion coatings. This scientific article endeavours to explore the efficacy, mechanisms, and potential applications of this composite material as an effective barrier against corrosion, shedding light on its transformative impact within corrosion mitigation strategies. In this study, bitumen was modified using epoxy resin ELM-NG900Z and hardener in a ratio of 1.0: 5: 1.5 respectively. The modified bitumen was further tested by mechanical tests and solvent tests. The samples of modified bitumen successfully passed the tests and showed results better than the reference(epoxy resin without bitumen). © 2024, Institute of Metallurgy and Ore Beneficiation JSC. All rights reserved.

The object of the study is a portable system that allows real-time monitoring of the state of the heart for the timely provision of medical care. The task of detecting atrioventricular (AV) blocks in the conditions of free motor activity of the patient is being solved. To develop a method for detecting AV block, models of the electrical activity of the heart were used to take into account the spatiotemporal organization of the process of spreading excitation, analyze the dynamics of the behavior of the cardiovascular systems (CVS) for any value of the period of atrial excitation, and assess the degree of fitness of the CVS. The proposed method made it possible to determine the heart rate (HR) at which the development of AV block is possible. AV block of the III degree – heart rate 304 bpm; AV block of the II degree with the loss of half of the impulses – heart rate 260 bpm; AV block II degree with loss of individual impulses – heart rate 234 bpm; AV block of the 1st degree – heart rate 200 bpm. Prediction of AV block allows assessing the degree of “training” of the patient’s heart. The obtained quantitative results are consistent with the heart rate values known to modern health care. The developed method was implemented on the basis of a portable ECG monitoring system previously developed by the authors. Tests of the portable ECG monitoring system indicate an increase in the sensitivity and specificity of diagnosing cardiac arrhythmia and confirm the achievement of the goal of this study: improving the efficiency of diagnostics and expanding the functionality of the portable ECG monitoring system © 2022. Authors. This is an open access article under the Creative Commons CC BY license