Novel simple approach was elaborated for the preparation of fentanyl and sufentanil starting from commercially available, cheap 1-methyl-4-piperidone. Compared to existing syntheses new route is shorter, easily scalable, and does not require the use of expensive palladium catalysts, highpressure equipment, and chromatographic separations. Moreover, it allows for to avoidance of working with the unstable norsufentanil, which is prone to a facile acyl migration to the nitrogen atom of the piperidine core even at ambient temperature, resulting in contamination of the target product.

Abstract Purpose Compare long-term outcomes in patients with colorectal cancer with KRAS, NRAS, and BRAF gene mutations and wild-type genes. Methods The study had cohort retrospective design. The overall survival (OS) for 611 patients and disease-free survival (DFS) for 490 patients were evaluated using the Kaplan-Meier estimator as primary endpoint. Relative OS and DFS of patients with gene mutations and wild-type genes and risk factor analysis were performed as secondary endpoints. Results Patients with NRAS gene mutations had worse OS (p-value = 0.04) and patients with KRAS gene mutation had worse DFS (p-value = 0.02) both compared to wild-type genes patients. 3-year OS rate was 86%, 74% 67% and 78% and 3-year DFS rate was 50%, 34% 50% and 46% for patients with the wild-type genes, KRAS, NRAS and BRAF gene mutations, respectively. Complete cytoreduction (HR 0.20, p-value < 0.005) and stage II (HR 0.07, p-value = 0.01) of the disease were associated with a lower risk of death. A KRAS gene mutations (HR 1.61, p-value = 0.01), neoadjuvant chemotherapy (HR 1.52, p-value = 0.04), and incomplete resection (HR 1.83, p-value = 0.03) were associated with a high risk of recurrence, while stages I-III compared with stage IV (HR 0.32, p-value = 0.01; HR 0.22, p-value < 0.005; HR 0.26, p-value < 0.005) were associated with a lower risk of recurrence. Conclusion RAS/BRAF mutations associated with worse CRC survival, however, advanced stage, incomplete cytoreduction and resection (R1) are also significant risk factors for death and CRC recurrence. Thus, early colorectal cancer diagnostic and radical and complete tumor resection allow to improve overall and disease-free survival for all patients.

Currently, there is a growing interest in biomedical research in the use of inorganic nanoparticles for targeted drug delivery, as biosensors, and in theranostic applications. This review examines the interaction of inorganic nanoparticles with protein molecules depending on the chemical nature, size, and surface charge of the nanoparticles. The effect of protein and nanoparticle concentration, as well as their incubation time, is analyzed. The work focuses on the influence of parameters such as pH, ionic strength, and temperature on the interaction of nanoparticles with protein molecules. The following dependencies were studied in detail: the thickness of the protein corona as a function of nanoparticle size; the size of nanoparticles after interaction with protein as a function of protein and nanoparticle concentration; the distribution of zeta potentials in colloids of nanoparticles, proteins, and their mixtures. It has been shown that proteins and nanoparticles can influence each other’s physicochemical properties. This can lead to the emergence of new biological properties in the system. Therefore, the adsorption of proteins onto nanoparticle surfaces can induce conformational changes. The probability of changing the protein structure increases when a covalent bond is formed between the nanoparticle and the protein molecule. Studies demonstrate that protein structure remains more stable with spherical nanoparticles than with rod-shaped or other high-curvature nanostructures. The results presented in the review demonstrate the possibility of adapting physiological responses to nanomaterials by changing the chemical composition of the surface of nanoparticles and their size and charge.

This manuscript presents a study on the dynamics of fiber Bragg grating formation using femtosecond radiation in the point-by-point inscription regime. By employing a multi-pass inscription technique, the dynamics of the photoinduced formation of modified regions (strokes) were investigated through an analysis of the evolution of the Bragg grating’s parameters. The results demonstrate a decrease in the average effective refractive index during the grating inscription. This study highlights the complexity of the structural transformations induced in the optical fiber core material by femtosecond laser radiation.

The presence of solid particles (or droplets) in a flow leads to a significant increase in heat fluxes, the occurrence of chemical reactions, and erosive surface wear of various aircraft moving in the dusty (or rainy) atmosphere of Earth or Mars. A review of computational, theoretical, and experimental work devoted to the study of the characteristics of the boundary layers (BL) of gas with solid particles was performed. The features of particle motion in laminar and turbulent boundary layers, as well as their inverse effect on gas flow, are considered. Available studies on the stability of the laminar boundary layer and the effect of particles on the laminar–turbulent transition are analyzed. At the end of the review, conclusions are drawn, and priorities for future research are discussed.

Wildfires significantly impact ecosystem dynamics and forest management strategies globally, including in Siberian forests. This study develops a machine learning (ML) framework to estimate wildfire size by integrating meteorological variables, forest composition, detection techniques, and historical fire records within the Krasnoyarsk Krai region of central Siberia. The dataset includes temperature, humidity, wind speed, precipitation, geospatial coordinates, and proximity to human settlements, which are used to train multiple predictive models, including XGBoost, Random Forest, K-Nearest Neighbors, Logistic Regression, and Decision Tree. XGBoost achieved the highest classification accuracy of 88.8%, outperforming other methods. Feature importance analysis highlights the influence of urban proximity, wind patterns, and meteorological conditions related to fuel moisture on fire size prediction. SHAP (SHapley Additive exPlanations) analysis indicates that smaller fires are associated with localized weather conditions, while extended dry periods correspond to larger fire events. While these results demonstrate the potential of ML for fire size classification in this specific region, the framework should be considered exploratory and region-specific. Future applications to other areas will require local data calibration.

This paper surveys the application of machine learning in fiber composite manufacturing, highlighting its role in adaptive process control, defect detection, and real-time quality assurance. First, the need for ML in composite processing is highlighted, followed by a review of data-driven approaches—including predictive modeling, sensor fusion, and adaptive control—that address material heterogeneity and process variability. An in-depth analysis examines six case studies, among which are XPBD-based surrogates for RL-driven robotic draping, hyperspectral imaging (HSI) with U-Net segmentation for adhesion prediction, and CNN-driven surrogate optimization for variable-geometry forming. Building on these insights, a hybrid AI model architecture is proposed for natural-fiber composites, integrating a physics-informed GNN surrogate, a 3D Spectral-UNet for defect segmentation, and a cross-attention controller for closed-loop parameter adjustment. Validation on synthetic data—including visualizations of HSI segmentation, graph topologies, and controller action weights—demonstrates end-to-end operability. The discussion addresses interpretability, domain randomization, and sim-to-real transfer and highlights emerging trends such as physics-informed neural networks and digital twins. This paper concludes by outlining future challenges in small-data regimes and industrial scalability, thereby providing a comprehensive roadmap for ML-enabled composite manufacturing.

In this study, we search for a design solution to ensure a reliable and long-term operation of a friction unit with a ceramic plain bearing. To that end, the stress-strain state of the ceramic insert is optimized with respect to actual loading conditions. The bearing unit is designed accounting for the properties of ceramic materials, which show low strength reliability under the action of tensile stresses. To improve the solution accuracy, we determine the actual contact area, taking into account the load unevenness in the bearing. In addition, since the insert surface is assumed to be complexly stressed, the calculation is based on equivalent stresses. The criterion is to minimize equivalent stresses, which corresponds to the optimal tension justifying the bearing application. The analysis involves the discrete-continuous option of the finite element method with the variational principle according to the Lagrange method. The calculation software provides for the values of equivalent stresses depending on tension and selects its optimal value. As a result of the performed analysis, the geometric shape of the ceramic insert is optimized. In the proposed design, the brittleness inherent in ceramic materials can almost be compensated by minimizing tensile stresses. Thus, the reliability and durability of the plain bearing increase. An original design of a plain bearing with a ceramic insert is proposed. This design allows advanced ceramic structural materials to be used in plain bearings, which extends the operational range of friction units. In order to overcome the fragility of ceramic materials, special design techniques should be developed to withstand tensile stresses through optimally selected tensions creating compressive stresses in the insert. Optimal tension parameters can be selected using numerical methods of stress-strain state analysis, in particular, the finite element method.

The purpose of the work is to reduce the weight of the rear suspension system of a truck with a gross weight of 3500 kg.Methods. To reduce the weight and determine the required mechanical characteristics of the suspension system, a search is carried out for rational parameters of a spring made of fiberglass, taking into account the manufacturing features using the finite element analysis method.Results. A rational design of a composite spring from the point of view of minimum weight is obtained. The optimal distribution of composite layers and its reinforcement angles across the spring thickness is determined. The load characteristic of the resulting spring, made using a polymer composite material, is constructed.Conclusion. Optimization of the composite spring made of fiberglass is carried out. The resulting spring has a nonlinear load characteristic. Under the action of a dynamic force, the spring failure criterion does not exceed 1, which indicates its operability.

Electrons localized by water molecules are known as hydrated electrons. The composition of the aqueous environment determines their state and behavior. In this experimental and theoretical work, hydrated electrons were formed in aqueous solutions upon high-energy electron impact, and the dependence of their characteristics on the presence of nanobubbles generated during vibrational treatment was investigated. To explain the results, quantum chemical simulations were carried out, and diverse possible kinetic schemes were considered. Absorbance of deionized water and NaCl aqueous solution was measured at a wavelength of 600 nm, which falls in the range typical of hydrated electrons. The principal differences in the spectral responses of the samples were discovered depending on whether they were preliminarily subjected to repeated vigorous shaking or not. Vigorous shaking caused a noticeable increase in both the integral and maximum absorbance, and the absorbance decay was significantly slower. The effects observed in the vibrationally treated aqueous samples were found to be explained only in the framework of a kinetic scheme that assumes the repeated solvation of electrons, which are transferred from a localized to a delocalized (free) state upon the energy absorption. This repeated solvation is possible only when the secondary electrons are localized on the inner surfaces of the boundary hydration shells of nanobubbles, which are formed in the process of shaking. Thus, nanobubbles substantially change the apparent gross lifetime and properties of hydrated electrons, and these changes, in turn, can indicate the presence of nanobubbles in water and aqueous solutions.