Search Results (164)

The aim of this study was to improve the efficiency of in situ uranium leaching by developing a specialized methodology for selecting rational parameters for the chemical treatment of production wells. This approach was designed to enhance the filtration properties of ores and extend the uninterrupted operation period of wells, considering the clay content of the productive horizon, the geological characteristics of the ore-bearing layer, and the composition of precipitation-forming materials. The mineralogical characteristics of ore and precipitate samples formed during the in situ leaching of uranium under various mining and geological conditions at a uranium deposit in the Syrdarya depression were identified using an X-ray diffraction analysis. It was established that ores of the Santonian stage are relatively homogeneous and consist mainly of quartz. During well operation, the precipitates formed are predominantly gypsum, which has little impact on the filtration properties of the ore. Ores of the Maastrichtian stage are less homogeneous and mainly composed of quartz and smectite, with minor amounts of potassium feldspar and kaolinite. The leaching of these ores results in the formation of gypsum with quartz impurities, which gradually reduces the filtration properties of the ore. Ores of the Campanian stage are heterogeneous, consisting mainly of quartz with varying proportions of clay minerals and gypsum. The leaching of these ores generates a variety of precipitates that significantly reduce the filtration properties of the productive horizon. Effective compositions and concentrations of decolmatant (clog removal) solutions were selected under laboratory conditions using a specially developed methodology and a TESCAN MIRA scanning electron microscope. Based on a scanning electron microscope analysis of the samples, the effectiveness of a decolmatizing solution based on hydrochloric and hydrofluoric acids (taking into account the concentration of the acids in the solution) was established for the destruction of precipitate formation during the in situ leaching of uranium. Geological blocks were ranked by their clay content to select rational parameters of decolmatant solutions for the efficient enhancement of ore filtration properties and the prevention of precipitation formation. Pilot-scale testing of the selected decolmatant parameters under various mining and geological conditions allowed the optimal chemical treatment parameters to be determined based on the clay content and the composition of precipitates in the productive horizon. An analysis of pilot well trials using the new approach showed an increase in the uninterrupted operational period of wells by 30%–40% under average mineral acid concentrations and by 25%–45% under maximum concentrations with surfactant additives in complex geological settings. As a result, an effective methodology for ranking geological blocks based on their ore clay content and precipitate composition was developed to determine the rational parameters of decolmatant solutions, enabling a maximized filtration performance and an extended well service life. This makes it possible to reduce the operating costs of extraction, control the geotechnological parameters of uranium well mining, and improve the efficiency of the in situ leaching of uranium under complex mining and geological conditions. Additionally, the approach increases the environmental and operational safety during uranium ore leaching intensification. Full article

This paper presents the results of studies on intra-annual runoff changes in the Ile River basin based on data from gauging stations up to 2021. Changes in climatic characteristics that determine runoff formation in the mountainous and foothill areas of the river catchment have led to alterations in the water regime of the watercourses. The analysis of the temporal and spatial patterns of river flow formation in the basin, as well as its distribution by seasons and months, is essential for solving applied water management problems and assessing the risks of hazardous hydrological phenomena, such as high floods and low water levels. The statistical analysis of annual and monthly river runoff fluctuations enabled the identification of relatively homogeneous estimation periods during stationary observations under varying climatic conditions. The obtained characteristics of annual and intra-annual river runoff in the Ile River basin for the modern period provide insights into changes in average monthly water discharge and, more broadly, runoff volume during different phases of the water regime. In the future, these characteristics are expected to guide the design of hydraulic structures and the rational use of surface runoff in this intensively developing region of Kazakhstan. Full article

To investigate the phenomenon of liquid xenon flashing in a filling pipeline, the two-phase flow in a pipe is calculated and analyzed by using a one-dimensional homogeneous equilibrium model (HEM) and a two-dimensional mixture model. The distribution of xenon two-phase flow parameters along the pipeline is observed by the numerical solution of a one-dimensional HEM and simulation by Fluent. The comparison and analysis of the results of different models show that the one-dimensional HEM can quickly attach the critical mass flux faster than Fluent’s simulation under the given filling conditions, which verifies the rationality and rapidity of the numerical solution in calculating the flash process. The influence of the diameter and length of the pipeline on the flashing process of liquid xenon is analyzed by a one-dimensional theoretical model. The results show that the geometric parameters of the pipeline have a great impact on the mass flow rate and the position of the initial phase transition point, but have little effect on the void fraction at the outlet. An increase in pipe diameter and pipeline length delays the onset of phase transition. Compared with liquid oxygen and liquid nitrogen, liquid xenon is more likely to undergo a phase transition. The phase change kinetics of oxygen and nitrogen are roughly 70% as fast as those of xenon. Full article

Hydroformylation is one of the most widely applied homogeneous catalytic processes in the chemical industry, constituting the predominant manufacturing platform for aldehyde synthesis at commercial scales. Nevertheless, hydroformylation shares with traditional homogeneous catalysis the inherent limitation of difficult catalyst recovery and recycling. Developing heterogeneous catalysts for such reactions is thus critically needed. Herein, a stable nitrogen-rich covalent triazine framework (CTF) was synthesized via a mild Friedel–Crafts alkylation method and employed as a support for Rh single-atom catalysts (Rh/CTF-TPA). In the hydroformylation of 1-decene, the Rh/CTF-TPA catalyst exhibits an exceptional reaction efficiency (TOF > 1900 h⁻¹), outperforming the homogeneous Rh(CO)₂(acac). Experimental and characterization results revealed that the CTF support enhances catalytic performance through two key mechanisms: (1) strong enrichment of reactants within its special structure, and (2) efficient dispersion of Rh single-atom sites stabilized by abundant nitrogen coordination. This work demonstrates a rational design strategy for heterogeneous hydroformylation catalysts by leveraging nitrogen-rich porous frameworks to synergistically optimize metal anchoring and reactant enrichment, offering a promising alternative to conventional homogeneous systems. Full article

Majority of commercial L-asparaginase (L-ASNase) activity assays are based on coupled enzymatic reaction, which converts aspartate into pyruvate, subsequently reacting with the probe to form a stable chromophore, which can be detected spectrophotometrically. However, in complex biological samples this method can be inaccurate due to poor optical transparency or presence of compounds interfering with the coupled enzyme reaction–for this kind of cases alternative methods have been suggested. Here we suggest a strategy to rationally pick a method of choice in a variety of situations, taking into consideration the upsides and downsides of each method. A high-throughput fluorometric assay employing the substrate Asp-AMC was rigorously validated for L-ASPNase activity screening. Aassay performance is evaluated in complex biological matrices, including bovine serum, whole and diluted human blood, and finally the mouse blood and liver homogenates samples obtained from pharmacokinetic studies. This comprehensive validation process ensures the reliability and applicability of the assay for assessing L-asparaginase activity in diverse and physiologically relevant environments. Potential interfering factors and matrix effects were addressed, and assay conditions were optimized for each matrix. The optimized assay was employed to screen various L-asparaginase types (intracellular L-ASNases type I RrA, periplasmic L-ASNases type II EcA and EwA) and ASPNase formulations (conjugates with polyamines or polyelectrolyte complexes), comparing their kinetic parameters and stability. Fourier-transform infrared (FTIR) spectroscopy was further employed to investigate the fine features of molecular mechanisms of L-asparaginase catalysis. FTIR spectra of Asn during hydrolysis were analyzed in buffer solutions and in complex biological matrices, such as blood sample or liver homogenates which is crucial in the context of pharmacokinetic research. This combined fluorometric and FTIR approach provides a powerful platform for optimizing L-ASNase formulations and therapeutic strategies for ALL. Based on the results obtained we have developed a strategy to choose an approach for L-Asparaginase activity assessment for a variety of difficult situations when dealing with complex biological samples. Full article

Understanding the reaction pathway of aldehyde deformylation catalyzed by natural enzymes has shown significance in developing synthetic methodologies and new catalysts in organic, biochemical, and medicinal chemistry. However, unlike other well-rationalized chemical processes catalyzed by cytochrome P450 (Cyt P450) superfamilies, the detailed mechanism of the P450-catalyzed aldehyde deformylation is still controversial. Challenges lie in establishing synthetic models to decipher the reaction pathways, which normally are homogeneous systems for precisely mimicking the structure of the active sites in P450s. Herein, we report a heterogeneous Cyt P450 aromatase mimic based on a porphyrinic metal–organic framework (MOF) PCN-224. Through post-metalation of iron(II) triflate with the porphyrin unit, a five-coordinated Fe^II(Porp) compound could be afforded and isolated inside the resulting PCN-224(Fe) to mimic the heme active site in P450. This MOF-based P450 mimic could efficiently catalyze the oxidative deformylation of aldehydes to the corresponding ketones under room temperature using O₂ as the sole oxidant and triethylamine as the electron source, analogous to the NADPH reductase. The catalyst could be completely recovered after the catalytic reaction without undergoing structural decomposition or compromising its reactivity, representing it as one of the most valid mimics of P450 aromatase from both the structural and functional aspects. A mechanistic study reveals a strong correlation between the catalytic activity and the C^α-H bond dissociation energy of the aldehyde substrates, which, in conjunction with various trapping experiments, confirms an unconventional mechanism initiated by hydrogen atom abstraction. Full article

Slope instability often brings serious threats to human production and life, which causes huge economic losses. The slope displacement calculation under seismic action is very important to ensure the safety and stability of a slope. At present, there are few studies on the displacement calculation of multi-stage loess slopes under seismic action. Based on the basic theory of soil dynamics and the introduction of the comprehensive slope ratio, this paper proposes a new displacement calculating method of multi-stage homogeneous loess slopes under seismic action and provides the calculation formula. The rationality of the theoretical calculation is verified using the numerical simulation software Geo Studio (V2022). The study shows that it is feasible to simplify the geometric characteristics of multi-stage loess slopes by adopting the comprehensive slope ratio, which can also reasonably reflect the displacement characteristics of multi-stage loess slopes under seismic action. The example verification shows that the deviation of the peak horizontal displacement between the calculating method of this paper and the numerical simulation result is 5.5%, which shows that the calculation method of this paper is reasonable and has a certain application value. Full article

Small cell lung cancer (SCLC) is a highly aggressive malignancy characterized by rapid progression, early metastasis, and high recurrence rates. Historically considered a homogeneous disease, recent multi-omic studies have revealed distinct molecular subtypes driven by lineage-defining transcription factors, including ASCL1, NEUROD1, POU2F3, and YAP1, as well as an inflamed subtype (SCLC-I). These subtypes exhibit unique therapeutic vulnerabilities, thereby paving the way for precision medicine and targeted therapies. Despite recent advances in molecular classification, tumor heterogeneity, plasticity, and therapy resistance continue to hinder clinical success in treating SCLC patients. To this end, novel therapeutic strategies are being explored, including BCL2 inhibitors, DLL3-targeting agents, Aurora kinase inhibitors, PARP inhibitors, and epigenetic modulators. Additionally, immune checkpoint inhibitors (ICIs) show promise, particularly in immune-enriched subtypes of SCLC patients. Hence, a deeper understanding of SCLC subtype characteristics, evolution, and the regulatory mechanisms of subtype-specific transcription factors is crucial for rationally optimizing precision therapy. This knowledge not only facilitates the identification of subtype-specific therapeutic targets, but also provides a foundation for overcoming resistance and developing personalized combination treatment strategies. In the future, the integration of multi-omic data, dynamic molecular monitoring, and precision medicine approaches are expected to further advance the clinical translation of SCLC subtype-specific therapies, ultimately improving patient survival and outcomes. Full article

Microorganisms have a profound impact on the stability and ecological health of aquatic environments. Fungi, as important components of river ecosystems, play critical roles as decomposers and symbionts. A comprehensive understanding of the mechanisms underlying fungal community assembly is essential for the effective conservation and management of river ecosystems. However, the distribution patterns and assembly process of fungal communities along elevation gradients in river sediments remain poorly understood. In this study, ITS amplicon sequencing, a neutral community model, and a null model were employed to analyze the distribution patterns and assembly processes of fungal communities in sediments along the altitudinal gradient of the Yellow River. The results indicated that Ascomycota (47.79%) and Basidiomycota (15.68%) were identified as the dominant phyla in the sediments, collectively accounting for 63.47% of the total relative abundance of the community. In the three different altitudinal gradients, the fungal community diversity (Shannon) showed a gradually decreasing trend with increasing altitude. The co-line networks of fungal communities exhibited positive interactions and had more complex and compact networks in the sediments of the Tibetan Plateau area (YRA). Environmental factors in the sediments played an important role in shaping the structure of fungal communities, with lead (Pb), total nitrogen (TN), silt, and total organic carbon (TOC) being the main factors driving changes in community structure, contributing 15.5%, 12.3%, 10.7%, and 10.2%, respectively. In the community assembly process, deterministic processes were found to dominate, with homogenizing selection contributing the most (69.66%). These research results help us understand the distribution patterns of fungal communities along altitudinal gradients and the mechanisms of community assembly, and also provide a scientific basis for biodiversity conservation and the rational use of biological resources. Full article

Tapered piles are a new type of pile foundation known for their simple construction and high bearing capacity, commonly used in railway, highway, or building foundation treatment. This study proposes a unified dynamic Winkler model for vertical and lateral vibration response of tapered piles in the frequency domain using the impedance function transfer matrix method. The computational expressions are obtained for the different springs and damping of tapered piles with different dimensions using the elastodynamic theoretical of rigid embedded foundations, and the dynamic interaction mechanisms of vertical and lateral vibrations between tapered piles and soil are analyzed. The rationality of the simplified model is validated by comparison with existing literature and finite element simulation results. Finally, an example is provided to discuss the influences of the dimensional parameters of the pile and soil properties on vertical, lateral, and rocking dynamic impedance. The analytical findings demonstrate that the lateral and rocking dynamic impedances of tapered piles undergo a substantially greater enhancement relative to their vertical counterpart as the taper angle is progressively enlarged, assuming the pile volume remains constant. The dynamic impedance of tapered piles under vertical and lateral vibration in upper hard and lower weak soil layers, or upper weak and lower hard soil layers, are both greater than those in a homogeneous foundation. Specifically, the vertical dynamic stiffness of tapered piles in double-layered soils is approximately twice that of homogeneous soil. The rocking dynamic stiffness of the pile is significantly influenced by the soil properties around the pile foundation, whereas the soil properties have little impact on the rocking damping coefficient. Overall, the vertical dynamic characteristics are less influenced by the geometric features of the upper part of the tapered pile, while the lateral dynamic characteristics are significantly affected by these features. The lateral dynamic impedance of the tapered pile increases with the diameter of the upper part of the pile. Furthermore, the vertical, lateral, and rocking dynamic impedance of the pile can be effectively improved by enhancing the soil properties around its upper section. These results can provide theoretical references for the engineering practice. Full article

The problem of obtaining a final expression for a function initially given in the form of a trigonometric Fourier series is considered. We consider a special case of a series when the coefficients of the series are known and are rational functions of the harmonic number. To obtain the final expression, we propose to formulate a differential equation with constant coefficients for the function. A special feature of the proposed approach is the consideration of non-homogeneous equations, with the sum of the divergent Fourier series as the non-homogeneity. In this way, it is possible to compose expressions for the desired functions in the form of quadratures and formulate sufficient conditions for the representability of the desired function in the form of piecewise Liouville elementary functions. In this case, it becomes possible to describe in the language of distribution theory a class of Fourier series that can be summed in a finite form using the method of A. N. Krylov. Full article

To enhance the sustainability of marginal olive and dairy farms in the Sorrento peninsula, two separate crossover trials were conducted on two farms in the area to evaluate olive pruning residue (OlPr) and olive mill leaves (OlLes) as forage sources for lactating cows. Each trial lasted six weeks and consisted of two treatment periods, each including a 15-day adaptation phase followed by a 6-day measurement phase. During the measurement phase, milk production, feed intake, and olive residue consumption were assessed for two homogeneous cow groups: one receiving a ration supplemented with olive by-products and the other receiving a control diet. The olive-supplemented groups exhibited higher dry matter intake and roughage consumption (hay + olive residue) compared to the control groups. The intake of OlLes was about 30% higher than that of OlPr. Compared to the respective control, milk from OlLe-fed cows a had higher fat content and a higher fat-to-protein ratio, a more favorable fatty acid composition in terms of higher monounsaturated and polyunsaturated fatty acids and conjugated linoleic acid contents, a reduced atherogenic index, and a saturated-to-unsaturated ratio. Likely due to the lower level of olive by-product ingestion, only marginal differences were observed in milk fatty acid composition of cows fed OlPr compared to the control. We conclude that the use of OlLes in dairy cow diets may represent a promising strategy for improving milk quality, promoting a more circular agricultural system, reducing reliance on external feed inputs, and mitigating the environmental impact of both olive and milk production. Full article

In the field of ensemble learning, bagging and stacking are two widely used ensemble strategies. Bagging enhances model robustness through repeated sampling and weighted averaging of homogeneous classifiers, while stacking improves classification performance by integrating multiple models using meta-learning strategies, taking advantage of the diversity of heterogeneous classifiers. However, the fixed weight distribution strategy in traditional bagging methods often has limitations when handling complex or imbalanced datasets. This paper combines the concept of heterogeneous classifier integration in stacking with the weighted averaging strategy of bagging, proposing a new adaptive weight distribution approach to enhance bagging’s performance in heterogeneous ensemble settings. Specifically, we propose three weight generation functions with “high at both ends, low in the middle” curve shapes and demonstrate the superiority of this strategy over fixed weight methods on two datasets. Additionally, we design a specialized neural network, and by training it adequately, validate the rationality of the proposed adaptive weight distribution strategy, further improving the model’s robustness. The above methods are collectively called func-bagging. Experimental results show that func-bagging has an average 1.810% improvement in extreme performance compared to the base classifier, and is superior to stacking and bagging methods. It also has better dataset adaptability and interpretability than stacking and bagging. Therefore, func-bagging is particularly effective in scenarios with class imbalance and is applicable to classification tasks with imbalanced classes, such as anomaly detection. Full article

Titanium dioxide (TiO₂) has emerged as a candidate anode material for sodium-ion batteries (SIBs). However, their applications still face challenges of poor rate performance and low initial coulomb efficiency (ICE), which are induced by the unstable solid-electrolyte interface (SEI) and sluggish Na⁺ diffusion kinetics in conventional ester-based electrolytes. Herein, inspired by the electrode/electrolyte interfacial chemistry, tetrahydrofuran (THF) is exploited to construct an advanced electrolyte and reveal the relationship between the improved electrochemical performance and the derived SEI film on TiO₂ anode. The robust and homogeneously distributed F-rich SEI film formed in THF electrolyte favors fast interfacial charge transfer dynamics and excellent interfacial stability. As a result, the THF electrolyte endows the TiO₂ anode with greatly improved ICE (64.5%), exceptional rate capabilities (186 mAh g⁻¹ at 5.0 A g⁻¹), and remarkable cycling stability. This study elucidates the control of interfacial chemistry by rational electrolyte design and offers insights into the development of high-performance and long-lifetime TiO₂ anode. Full article

Rifaximin and rifampicin are good broad-spectrum antimicrobials. The irrational use of antimicrobial drugs in veterinary clinics could threaten public health and food safety. It is necessary to develop a reliable detection method of the residue for enhancing the rational supervision of the use of such drugs, reducing and slowing down the generation of bacterial resistance, and promoting animal food safety and human health. So, this study developed an LC-MS/MS method for the detection of rifaximin and rifampicin residues in animal-origin foods. The residual rifaximin and rifampicin of homogenized test materials were extracted with acetonitrile-dichloromethane solution or acetonitrile in the presence of anhydrous sodium sulfate and vitamin C, purified by dispersible solid phase extraction, determined by LC-MS/MS, and quantified by the internal standard method. The specificity, sensitivity, matrix effect, accuracy, and precision of the method were investigated in the edible tissues of cattle, swine, or chicken. In addition, the stability of the standard stock solution and the standard working solution was also investigated. The method was suitable for the muscle, liver, kidney, fat, milk, and eggs of cattle, swine, or chicken, as well as fish and shrimp. The specificity of the method was good, and the detection of the analytes was not affected by different matrices. Both the LOD and LOQ of the two analytes were 5 μg/kg and 10 μg/kg, respectively. The results of matrix effects in each tissue were in the range of 80–120%; there were no significant matrix effects. The average accuracy of rifaximin and rifampicin in different foodstuffs of animal origin was between 80% and 120%, and the method precision was below 20% (RSD). The proposed method showed good performance for determination, which could be employed for the extraction, purification, and detection of residual rifaximin and rifampicin in edible animal tissues. The pretreatment procedure of tissue samples was simple and feasible. The method was highly specific, stable, reliable, and with high sensitivity, accuracy, and precision, which met the requirements of quantitative detection of veterinary drug residues. Full article