Materials Science Research Articles

Superstrong and tough silk fibers cross-linked with functionalized graphene

Natural silkworm silks with an intriguing integration of good strength, modulus, toughness and biocompatibility, have been widely used in textile and medical industry. However, the strength of silkworm silks is inferior to that of spider dragline silks, which are the strongest natural silks but extremely low yield. Herein, we develop a feasible strategy to continuously produce superstrong and tough regenerated silk fibers (RSFs) through the reconstruction of hierarchical and cross-linked architectures. Amine functionalized graphene (NH2-G) has been introduced to improve the content of β-sheet and crystalline orientation, and glutaraldehyde (GA) has been used to bridge NH2-G and silk micro/nanofibrils (SNFs) to form a highly interconnected and closely packed network, resulting in the remarkably improvement of mechanical properties. The resultant fibers exhibit an excellent tensile strength of 1029.6 ± 144.8 MPa, a Young's modulus of 16.8 ± 1.5 GPa, and a toughness of 277.4 ± 17.0 MJ/m3, exceeding those of the natural silkworm silks, spider dragline silks and most other previously reported regenerated silk fibers. We believe that the high-performance silk-based fibers are promising applications in lightweight and advanced structural materials.

Deciphering the storage mechanism of biochar anchored with different morphology Mn3O4 as advanced anode material for lithium-ion batteries

Biochar is regarded as a promising lithium-ion batteries anode material, owing to its high cost-effectiveness. However, the poor specific capacity and cycling stability have limited its practical applications. A straightforward and cost-efficient solvothermal method is presented for synthesizing Mn3O4/biochar composites in this study. By adjusting solvothermal temperatures, Mn3O4 with different morphology is prepared and anchored on the biochar surface (MKAC-T) to improve the electrochemical performance. Due to the morphological effect of nanospherical Mn3O4 on the biochar surface, the MKAC-180 anode material demonstrates outstanding reversible capacity (992.5 mAh/g at 0.2 A/g), significant initial coulombic efficiency (61.1 %), stable cycling life (605.3 mAh/g at 1.0 A/g after 1000 cycles), and excellent rate performance (385.8 mAh/g at 1.6 A/g). Moreover, electro-kinetic analysis and ex-situ physicochemical characterizations are employed to illustrate the charge storage mechanisms of MKAC-180 anode. This study provides valuable insights into the “structure–activity relationship” between Mn3O4 microstructure and electrochemical performance for the Mn3O4/biochar composites, illuminating the industrial utilization of biomass carbon anode materials.

Analysis of the Impact of Globalization Trends in the Digital Economy on Business Management and Administration Systems of Enterprises

Aim. This study aims to investigate the impact of globalization trends on the business management and administration systems. Methodology. The scoping review of the literature included 123 articles through desk research and in-house material. Upon categorizing typologies as qualitative, quantitative, or mixed, an assessment was made regarding the performance and consequences of globalization from 1990 to 2022. Results. Developing country managers are more likely to depend on international sales as a means to augment revenue, due to the greater saturation of sales in developed markets. Developed economies focus on advanced, possibly automated production methods, whereas developing nations employ the digital economy to compete in less automated industries. This creates a more specialized global market..E-commerce in the digital economy makes it easier for developing nations to enter the global market and reach a global audience. In their pursuit of financial gain, corporations based in affluent nations are more likely to employ sophisticated production methods, while those situated in developing countries are more likely to utilize less advanced ones. A number of prevalent issues and trends—including economics, politics, emerging markets, corporate social responsibility, and emerging markets—were recognized as critical for the development of global markets. While past research has focused on globalization's effects on developed economies, this study examines emerging country managers' unique difficulties and opportunities. The emphasis on expanding international sales and potential manufacturing process reduction can inform management approaches in similar situations. Conclusion. The recommendations underscore the critical necessity for further investigation into the aforementioned impacts across diverse economies, ranging from developing to developed. Although this study encountered difficulties due to inconsistent and limited data, it established a strong foundation for subsequent investigations in the field through the application of operationalization, methodologies, and analyses discovered in the business literature.

Cationic Europium-Organic Framework for Chromatographic Column Separation of Ionic Dyes and Stimuli-Responsive Chromic Properties.

A novel 3D europium-based cationic framework (Eu-CMOF) has been constructed solvothermally by employing a viologen derivative as an organic functional building unit. Notably, Eu-CMOF demonstrates its capability as a proficient aqueous-phase ion-exchange host, facilitating the remarkable rapid chromatographic column separation of new coccine and malachite green (NC3-/MG+), as well as new coccine and methylene blue (NC3-/MLB+), in mere 2 to 4 min. Adsorption thermodynamics and kinetics of anionic dyes demonstrate that Eu-CMOF exhibits a higher adsorption capacity for NC3-, as evaluated by the Langmuir model, reaching a value of 173 mg·g-1. The pseudo-second-order rate constant is determined to be 3.84 × 10-3 mg-1·g·min-1. Additionally, Eu-CMOF displays reversible photochromic and amine- and ammonia-induced vapochromic behaviors. Further mechanistic studies reveal that these chromic behaviors are primarily attributed to the generation of free viologen radical stimulated by Xe-light or electron-rich amine/ammonia. This research contributes to the development of advanced materials with applications in rapid chromatographic separation and stimuli-responsive chromic properties, showcasing the potential of Eu-CMOF as a versatile platform for practical applications.

An insight into the influence of precipitation phase on the surface quality in diamond turning of an Aluminium alloy

Diamond turning is an effective technology for processing metal mirrors used in photoelectric communications, radar, and other fields. In diamond turning, the precipitated phase is an essential factor that influences the surface quality of the metal mirrors. However, in previous studies, the precipitation phase has typically been handled as a random variable in a surface morphology model to evaluate its influence on the surface roughness, instead of determining the formation mechanism and proposing suppression solutions. In this study, a new phenomenon is observed in the diamond turning of metal mirrors, that is, the micro diamond tool can reduce the protrusion of the precipitated phase under a small feed rate and improve the surface quality. Investigating the turning process using diamond tools with varying tool nose radii at small feed rates (<1 μm/r), the underlying transformation mechanism of the precipitation phase is determined with the advanced material characterization technologies. The growth of the precipitated phase with an increase in the tool nose radius is explained using the energy gradient theory. The results showed that the increased material strain on the machined surface decreased the activation energy of solute diffusion in the material, causing solute accumulation and precipitate phase growth. With a further increase of tool nose radius to around 1000 μm, the β'' phase breaks and rotates. The representative volume element method shows that when undergoing severe plastic deformation, dislocations and grain boundaries quickly aggregate and slide on the precipitated phase, which will lead to the fracture and rotation of β'' phase. These findings provide a theoretical basis for the development of highly smooth mirrors.

Comprehensive investigation of the electronic properties of zinc and cobalt doped hydroxyapatite

AbstractThis study presents a comprehensive investigation into the electronic properties of Hydroxyapatite (HAp) doped with Zinc (Zn) and Cobalt (Co). Five distinct compositions, denoted as 0.15Zn-HAp, 0.15Co-0.15Zn-HAp, 0.30Co-0.15Zn-HAp, 0.45Co-0.15Zn-HAp, and 0.6Co-0.15Zn-HAp (at%,) have been systematically studied employing Density of States (DOS) and band structure calculations. The computed band gap values for these compositions were determined to be 4.6663, 4.6888, 4.7049, 4.7159, and 4.7082 eV, respectively. These results illuminate the profound influence of Zn and Co doping on the electronic structure of Hydroxyapatite. These findings hold significant implications for the potential applications of these materials in diverse technological and biomedical domains. The systematic approach and precise electronic property characterizations presented in this study provide a robust foundation for further advancements in the realm of advanced materials, with particular relevance to the development of innovative materials for use in cutting-edge technologies and medical applications.

Step height measurement of monoatomic silicon crystal lattice steps with a commercial atomic force microscope

Abstract Precise control of advanced materials relies on accurate dimensional metrology at the sub-nanometre scale. At this scale, the accuracy of scanning probe microscopy (SPM) has been limited by the lack of traceable transfer standard artefacts with calibration structures of suitable dimensions. With the adoption in 2019 of the silicon crystal lattice spacing as a secondary realization of the metre in the International System of Units (SI), SPM users have direct access to a realization of the SI metre at the sub-nanometre level by means of the step height of self-assembled monatomic lattice steps that can form on the surface of silicon crystals. A key challenge of successfully adopting this pathway is establishing the need for established protocols to minimize measurement errors and artifacts in routine laboratory use.&amp;#xD;In this study, step height measurements of monoatomic lattice steps in an ordinal/staircase structure on a Si(111) crystal surface have been derived from images acquired with a commercially available, research-level atomic force microscope (AFM). Measurement results derived from AFM images using three different SPM image processing and analysis software packages are compared. Significant sources of measurement uncertainty are identified; principally the contribution from the dependence on scan direction. The calibration of the&amp;#xD;AFM derived from this measurment was used to traceably measure the sub-nanometre lattice steps on a silicon carbide crystal surface to demonstrate the viability of this calibration pathway.&amp;#xD;

Performance analysis and application fields of reactive powder concrete

Reactive Powder Concrete (RPC) is a novel concrete material prepared from highly active composite admixtures, cement, fine sand, and micro steel fibers through appropriate curing and processing techniques. RPC not only exhibits ultra-high strength and durability but also demonstrates outstanding toughness, good volume stability, and excellent environmental performance. Its use can reduce the demand for natural resources, extend the service life of structures, and reduce waste generation, aligning with the direction of sustainable development and green building. This makes it an ideal choice for constructing large-span lightweight structures and structures operating in harsh environmental conditions, attracting extensive research attention in the international engineering materials field. In summary, RPC, as a new type of concrete material, has broad application prospects in the construction field. With continuous research and technological development, RPC will undoubtedly bring more innovations and new solutions to the construction industry, promoting its continuous progress and development.

Perspective: Probing elasto-quantum materials with X-ray techniques and in situ anisotropic strain.

Anisotropic lattice deformation plays an important role in the quantum mechanics of solid state physics. The possibility of mediating the competition and cooperation among different order parameters by applying in situ strain/stress on quantum materials has led to discoveries of a variety of elasto-quantum effects on emergent phenomena. It has become increasingly critical to have the capability of combining the in situ strain tuning with X-ray techniques, especially those based on synchrotrons, to probe the microscopic elasto-responses of the lattice, spin, charge, and orbital degrees of freedom. Herein, we briefly review the recent studies that embarked on utilizing elasto-X-ray characterizations on representative material systems and demonstrated the emerging opportunities enabled by this method. With that, we further discuss the promising prospect in this rising area of quantum materials research and the bright future of elasto-X-ray techniques.&#xD.

Mass Transport and Energy Conversion of Magnetic Nanofluids from Nanoparticles’ Movement and Liquid Manipulation

Magnetic nanofluids, also referred to as ferromagnetic particle levitation systems, are materials with highly responsive magnetic properties. Due to their magnetic responsiveness, excellent controllability, favorable thermal characteristics, and versatility, magnetic nanofluids have sparked considerable interest in both industrial manufacturing and scientific research. Magnetic nanofluids have been used and developed in diverse areas such as materials science, physics, chemistry and engineering due to their remarkable characteristics such as rapid magnetic reaction, elastic flow capacities, and tunable thermal and optical properties. This paper provides a full and in-depth introduction to the diverse uses of ferrofluids including material fabrication, fluid droplet manipulation, and biomedicine for the power and machinery sectors. As a result, magnetic nanofluids have shown promising applications and have provided innovative ideas for multidisciplinary research in biology, chemistry, physics and materials science. This paper also presents an overview of the device construction and the latest developments in magnetic-nanofluid-related equipment, as well as possible challenging issues and promising future scenarios.

Grinding-stimulated fluorescence enhancement in carbon nanoparticles/poly(vinyl chloride) composite

The physical damage of engineering materials is challenging to perceive, particularly when they occur with only a slight extent. To present the location of damage to engineering is still difficult to achieve. Mechanical responsive engineering materials are therefore highly desired. Herein, a type of composites comprised of carbon nanoparticles (CNP) and poly(vinyl chloride) (PVC) was prepared via a heating incubation process. Notably, we found that these composites were in a metastable state and exhibited a grinding-stimulated fluorescence enhancement performance. After grinding stimulation, a bright orange-yellow color emission appeared and the fluorescence intensity of the composites exhibited a 75-fold enhancement. It was noted that grinding had no effect on the fluorescence of CNP alone. The fluorescence enhancement may be due to the change in the surface environment of CNP, as grinding facilitates the entry of CNP into PVC. In addition, fluorescence enhancement was also observed in tightening screw experiments using commercialized PVC films, demonstrating the abrasive-stimulated fluorescence enhancement properties of this CNP/PVC. Such remarkable mechanical response property and interesting combination between CNP and PVC will provide avenue to promote the development of smart engineering materials and have considerable potentials in external force response and structure damage surveying.

Innovative modeling of monolayer puckered arsenene: Bridging quantum mechanics and finite element analysis

Current study presents a novel hybrid approach combining finite element modeling and density functional theory calculations to investigate the mechanical properties of monolayer puckered arsenene. The multiscale analysis in this study leverages finite element analysis as a distinctive approach, complementing the nano‐scale capabilities of density functional theory and molecular dynamics by overcoming limitations faced by these two methods in representing complex scenarios. Furthermore, finite element analysis demonstrates computational efficiency for larger structures, making it suitable for systems where atomistic simulations may be impractical. This hybrid methodology offers a unique framework for accurately predicting key properties, including elastic modulus and buckling force, by synergistically integrating the strengths of both computational techniques. In addition to demonstrating the effectiveness of our approach in accurately capturing material behavior, our findings shed light on fundamental aspects of nanoscale mechanics, with implications for various applications in nanotechnology, materials science, and structural engineering. By providing a deeper understanding of the mechanical response of 2D materials, our research contributes to advancing the field of nanoscale materials engineering and informs the design of innovative nanostructures with tailored mechanical properties.

Uncertainty quantification in multivariable regression for material property prediction with Bayesian neural networks

With the increased use of data-driven approaches and machine learning-based methods in material science, the importance of reliable uncertainty quantification (UQ) of the predicted variables for informed decision-making cannot be overstated. UQ in material property prediction poses unique challenges, including multi-scale and multi-physics nature of materials, intricate interactions between numerous factors, limited availability of large curated datasets, etc. In this work, we introduce a physics-informed Bayesian Neural Networks (BNNs) approach for UQ, which integrates knowledge from governing laws in materials to guide the models toward physically consistent predictions. To evaluate the approach, we present case studies for predicting the creep rupture life of steel alloys. Experimental validation with three datasets of creep tests demonstrates that this method produces point predictions and uncertainty estimations that are competitive or exceed the performance of conventional UQ methods such as Gaussian Process Regression. Additionally, we evaluate the suitability of employing UQ in an active learning scenario and report competitive performance. The most promising framework for creep life prediction is BNNs based on Markov Chain Monte Carlo approximation of the posterior distribution of network parameters, as it provided more reliable results in comparison to BNNs based on variational inference approximation or related NNs with probabilistic outputs.

Concrete touchdown: new technology influences industrial buildings in Norway, 1912–1920

Construction technology developed quickly during the first decades of the twentieth century. This influenced the construction of industrial buildings at the UN Educational, Scientific and Cultural Organization World Heritage site of Rjukan and Notodden in Norway. Behind the construction was Hydro, a company founded in 1905 to produce synthetic nitrogen fertiliser to increase the world’s food production. This industrial development demanded large structures such as hydropower stations and production facilities. Concrete was introduced for the first time during this period, and systems are characterised by heavy concrete bearing walls and mixed bearing walls where concrete and steel were combined. Such systems demanded significant material resources and resulted in the development of steel and concrete skeleton frames. The development of viable systems was achieved through research in materials science and structural engineering, in both the USA and Europe. This paper discusses how concrete influenced construction and building systems at this site. Similarities to industrial buildings and other building typologies are evident and connect the site to the international context of architecture and engineering history. Understanding the characteristics of individual buildings and presenting them in an order of a construction systems will support the work of architects and engineers in future conservation schemes.

“On-Water” accelerated dearomative cycloaddition via aquaphotocatalysis

Sulfur(VI) fluoride exchange (SuFEx) has emerged as an innovative click chemistry to harness the pivotal connectivity of sulfonyl fluorides. Synthesizing such alkylated S(VI) molecules through a straightforward process is of paramount importance, and their water-compatibility opens the door to a plethora of applications in biorelevant and materials chemistry. Prior aquatic endeavors have primarily focused on delivering catalysts involving ionic mechanisms, studies regarding visible-light photocatalytic transformation are unprecedented. Herein we report an on-water accelerated dearomative aquaphotocatalysis for heterocyclic alkyl SuFEx hubs. Notably, water exerts a pronounced accelerating effect on the [2 + 2] cycloaddition between (hetero)arylated ethenesulfonyl fluorides and inert heteroaromatics. This phenomenon is likely due to the high-pressure-like reactivity amplification at the water-oil interface. Conventional solvents proved totally ineffective, leading to the isomerization of the starting material.

Photothermal superhydrophobic composite coatings based on n-tetradecane@CaCO3/TiN microcapsules for anti-/deicing

Ice accumulation on equipment and building surfaces is a scientific and modern engineering problem to be solved urgently. Compared to the energy-intensive and expensive active anti-/deicing approaches, passive energy-free technology based on advanced materials and surface engineering has received more attention. Herein, we successfully encapsulated n-tetradecane in calcium carbonate shell by in situ precipitation method, and the microcapsules reveal good energy-storage capability (99.9 %), latent heat (108.1 J g−1), and long-term durability. Combining the microcapsule with low-cost titanium nitride and low-surface-energy PDMS (polydimethylsiloxane) materials, the multifunctional superhydrophobic composite coating has been successfully prepared. The composite coating surface possesses strong absorption in UV–vis-NIR bands with high photothermal conversion and storage capability. The results indicate that the composite coating successfully prolongs the icing time compared to traditional photothermal superhydrophobic surfaces, and accelerates the melting of ice droplets under light illumination, which demonstrates great potential in both anti-icing and deicing applications.

Research on ship propeller noise reduction: Advanced materials and innovative geometric design

The noise reduction technology of ship propellers is currently one of the challenging directions, despite some progress having been made, continuous research and development are still underway. This paper elucidates commonly used noise reduction methods, namely geometric structure optimization and material optimization. Geometric structure optimization involves aspects such as the number of propeller blades, disk loading ratio, skew angle, and blade shape. Material optimization encompasses material selection, surface coating optimization, and propeller duct design. Corresponding optimization methods are provided for both approaches. A novel and innovative research direction is proposed, leveraging machine learning and neural networks to optimize propeller parameters. Additionally, employing a circumferential friction nanogenerator to sense propeller bearings and identify the coupling relationship between electrical signals and factors such as roughness and rotational speed. This optimization aims to reduce noise by optimizing propeller parameters. The paper concludes by offering insights for current research on ship propeller noise reduction technology in China.

Weak-formulated physics-informed modeling and optimization for heterogeneous digital materials

Abstract Numerical solutions to partial differential equations (PDEs) are instrumental for material structural design where extensive data screening is needed. However, traditional numerical methods demand significant computational resources, highlighting the need for innovative optimization algorithms to streamline design exploration. Direct gradient-based optimization algorithms, while effective, rely on design initialization and require complex, problem-specific sensitivity derivations. The advent of machine learning offers a promising alternative to handling large parameter spaces. To further mitigate data dependency, researchers have developed physics-informed neural networks (PINNs) to learn directly from PDEs. However, the intrinsic continuity requirement of PINNs restricts their application in structural mechanics problems, especially for composite materials. Our work addresses this discontinuity issue by substituting the PDE residual with a weak formulation in the physics-informed training process. The proposed approach is exemplified in modeling digital materials, which are mathematical representations of complex composites that possess extreme structural discontinuity. This paper also introduces an interactive process that integrates physics-informed loss with design objectives, eliminating the need for pre-trained surrogate models or analytical sensitivity derivations. The results demonstrate that our approach can preserve the physical accuracy in data-free material surrogate modeling but also accelerates the direct optimization process without model pre-training.

GERIATRIC ASPECTS OF THE ORGANIZATION OF MEDICAL-SOCIAL, PALLIATIVE AND HOSPICE CARE IN THE CONDITIONS OF THE WAR: COMBINATION OF MEDICAL, PSYCHOLOGICAL AND SOCIAL PROBLEMS

The aim of the study is to characterize, from the point of view of geriatric aspects, the current problems of the organization of medico-social, palliative and hospice care (PHC) and social services for palliative care in the war conditions based on multidisciplinary, interagency and inter-sectoral approaches, as well as a combination of medical, psychological and social problems. Materials and methods. The research materials were scientific literary sources and regulatory documents. A pilot survey of 200 people was conducted to study the psychological state and psychological support needs of the elderly and internally displaced persons (IDPs). The survey results of 3,705 client’s questionnaires of the “Vseturbota” Project were also evaluated, of which 63.6 % are people aged 67-84 years, 26.4 % are 85–101 years old. The following research methods were used in the work: bibliosemantic, sociological, system approach and system analysis. Results and discussion. After February 24, 2022, IDPs will experience significant difficulties, suffer from reduced income, increased dependence on humanitarian aid, do not feel safe and protected. All these are reflected in their psychological state. It was found that among respondents aged ≥75 years had the most people with medium (57.1 %) and low (25.0 %) levels of anxiety, 71.4 % had a low level of mood. 32.17 % of the “Vseturbota” Project clients needed additional consultation with a family doctor, 3.83 % needed consultation with a psychologist, and 3.35 % with other specialists. Most often, they needed help around the house (26.02 %), buying medicines/foodstuff (22.43 %), 34.97 % needed information, and 13.36 % needed psychological counseling. An important condition for providing geriatric patients, including IDPs, with affordable, high-quality and effective PHC is the creation of a system and service of ambulatory/mobile and inpatient PHC facilities and medico-social care. Conclusions. The military aggression of the Russian Federation caused considerable suffering to the population of Ukraine. The state of anxiety and fear has a negative impact not only on the psycho-emotional, but also on the physical sphere of the elderly, which necessitates the implementation of psychological services and effective strategies for overcoming stress and distress, which requires the development and implementation of mechanisms for interagency coordination and cooperation, involving and training of multidisciplinary teams’ specialists and volunteers, effective advocacy activities, etc.

THE INFLUENCE OF MILITARY EVENTS AS A SOCIALLY STRESS FACTOR ON THE SUICIDE MORTALITY RATE

Introduction. Russia's aggression, which began in 2014 with the occupation of Crimea and parts of Donetsk and Luhansk regions, is considered a powerful long-term socially stressful factor. The suicide rate, as an indicator of troubles in society and its health as a whole, helps to identify a vulnerable contingent of the population and evaluate the effectiveness of state preventive measures implemented in socially stressful conditions. The aim: to investigate the dynamics of suicide mortality in Ukraine for the period 2005-2021. and the impact on this indicator of a socially stressful factor – Russian aggression in order to determine the stability of Ukrainian society in the conditions of war, identify the most vulnerable contingent of the population and evaluate the state's multi-selective approach aimed at preventing suicide. Materials and methods. The research materials were official statistical data from the "Population of Ukraine" reports of the State Statistics Service of Ukraine for 2005-2021. Cases of suicide of men and women in the period 2005-2013 served as a comparison group. The analysis provided for the clarification of annual rates and dynamics of suicide mortality and its gender characteristics during the period of the social stress factor in 2014-2021, in comparison with the control period and world indicators (WHO). Bibliographic, epidemiological, analytical, statistical methods were used in the research. Results. In Ukraine, as well as in the world, in the period 2005-2021, a decrease in the death rate due to suicides is noted, however, the Ukrainian rates significantly exceed the world rates. In a relatively prosperous period, the mortality rate due to suicide was 20.8±0.3, and it decreased statistically significantly (p&lt;0.001) to 16.1±0.36 in the socially stressful period of 2014-2021. The number of suicides among the male population significantly exceeds its number among the female population and is significantly higher than the world indicators, in contrast to the female population, where the indicators are even lower. During the socially stressful period, the number of suicides among men remains reduced to 28.76±0.92 (р&lt;0.001) and among women to 5.64±0.3 (р&lt;0.05), with more stable rates of decline among women. Conclusions. In Ukraine, there is a dynamic decrease in the number of deaths due to suicides, which correlates with global indicators. However, our country, despite the faster rate of decline of this indicator, still belongs to the countries with a high rate of suicide mortality. During the military events of 2014-2021, the death rate from suicides decreased significantly, compared to the previous relatively prosperous period of 2005-2013 (p&lt;0.001), which indicates the stability of Ukrainian society in war conditions. Mortality due to suicides in Ukraine significantly prevails among men (p&lt;0.001) and significantly exceeds global indicators, which makes them a vulnerable contingent of the population that needs socially oriented support. The positive dynamics of the decrease in the number of suicides among men (p&lt;0.001) and women (p&lt;0.05) in the conditions of war testifies to the effectiveness of the state's multi-selective approach aimed at preventing suicide.