Search Results (70,433)

This paper analyzes the influence of different parameters on the seismic performance of reinforced concrete shear walls under granular lateral pressure through numerical simulation. The study focuses on the effects of these parameters on the yield load, peak load, and initial stiffness of the specimens, accompanied by parameter sensitivity analyses. The results indicate that as the grain loading height increases, the ultimate bearing capacity of the shear wall continuously decreases, while increases in concrete strength, axial compression ratio, and wall longitudinal reinforcement ratio lead to continuous improvement in the ultimate bearing capacity. Compared with concrete strength and wall longitudinal reinforcement ratio, increasing the axial compression ratio enhances the bearing capacity more significantly. Moreover, increasing the concrete strength and axial compression ratio effectively improves the initial stiffness of the specimen, whereas the influence of grain loading height and the wall longitudinal reinforcement ratio on the initial stiffness is limited. Within the parameter range considered, the standardized coefficients of concrete strength, axial compression ratio, grain loading height, and wall longitudinal reinforcement ratio on the peak load are 0.463, 0.678, −0.308, and 0.243, respectively. This further confirms that increasing the axial compression ratio can effectively improve the bearing capacity of the specimens. Full article

Metabolic rate is closely linked to body mass and is widely used to relate physiological processes to ecological and evolutionary patterns. In small aquatic organisms, measurements of oxygen consumption rate ($M{o}_2$) are often limited by instrument sensitivity. Although pooled respirometry is commonly used as a practical alternative, its reliability remains insufficiently evaluated in small freshwater invertebrates. This study examined measurement consistency among respirometry approaches and explored the relationship between body mass and metabolic rate in the freshwater shrimp Neocaridina denticulata. Oxygen consumption rate was measured in single individuals and pooled groups of three and five individuals. No significant differences were detected among treatments (one-way ANOVA, p > 0.05), and estimates were generally comparable across methods. Metabolic rate increased with body mass (R² = 0.746), and log–log regression yielded a scaling exponent of 0.99 (95% CI: 0.75–1.22), indicating an approximately isometric relationship. Overall, pooled respirometry produced results comparable to individual measurements. Within the experimental range examined, pooled respirometry provided reliable metabolic estimates without detectable systematic bias. These findings provide preliminary experimental support for pooled respirometry as a practical approach for metabolic measurements of small N. denticulata within the experimental conditions examined, particularly when individual measurements are constrained by instrument sensitivity. Full article

This study investigates the impact of critical raw material mining and processing on surface water quality within a representative catchment area, using the Luda Yana River Basin in Southern Bulgaria as a case study. Water quality was evaluated using the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI), based on data collected from five monitoring stations. The analysis focused on key heavy metals, including Cu, Zn, Pb, Cd, Fe, Mn, Ni, and As, reflecting the influence of both active and historical mining activities in the region. Index values were calculated for the period 2008–2024 and revealed considerable temporal variability and pronounced spatial differences in water quality along the river course. This study provides one of the first long-term integrated assessments of heavy-metal-related water quality in a mining-impacted river basin in Bulgaria using the CCME WQI framework and offers new evidence on the cumulative effects of historical and ongoing mining activities on surface waters. The calculated CCME WQI values ranged from very low levels indicating poor conditions to moderate values corresponding to marginal and, occasionally, fair conditions. Overall, the predominant water quality categories were “poor” and “marginal.” The results demonstrate that the waters of the studied river basin remain below the thresholds for “fair” physicochemical status as defined by the European Water Framework Directive (2000/60/EC) and the corresponding Bulgarian legislation, including Regulation No. H-4/2012 on surface water characterization and the 2010 Ordinance on environmental quality standards for priority substances and certain pollutants. The findings highlight the persistent anthropogenic pressure exerted on the river system and emphasize the need for improved water management strategies. The study further underlines the importance of integrating environmental protection measures into the exploitation of critical raw materials in order to balance economic development with the sustainable management of water resources. Full article

Precise control of dissolved oxygen is essential for reproducing physiologically relevant conditions in microfluidic cell culture systems. Here, we present a standalone, polydimethylsiloxane-free gas exchange unit (GEU) which enables controlled oxygenation and deoxygenation of perfused liquids and is suitable for integration with existing microfluidic platforms. The GEU employs a flat-sheet membrane contactor design to achieve efficient gas–liquid mass transfer while remaining independent of the downstream device. Oxygen transfer was experimentally characterised using optical oxygen sensors under different liquid and gas flow conditions. Reoxygenation efficiency decreased with increasing liquid flow rate because of reduced residence time, whereas active airflow through the gas compartment enhanced oxygen transfer. Controlled deoxygenation was achieved by flowing nitrogen through the gas compartment, with higher nitrogen pressures producing progressively lower oxygen levels. Numerical flow simulations demonstrated uniform flow distribution within the device, and a simplified analytical diffusion model accurately predicted the observed oxygen transfer trends. The proposed GEU provides a simple, robust and modular strategy for regulating dissolved oxygen upstream of microfluidic devices without requiring device redesign or specialised fabrication. This approach offers a practical solution for incorporating physiologically relevant oxygen control into a wide range of microfluidic and cell culture applications. Full article

Background and Objectives: This study aimed to compare the clinical, functional, and graft-related outcomes of two tibial fixation constructs used in primary hamstring autograft anterior cruciate ligament reconstruction (ACLR): tibial cortical button fixation and bioabsorbable interference screw fixation reinforced with a U-shaped staple. Materials and Methods: This retrospective two-center comparative cohort study included 58 patients with isolated anterior cruciate ligament injuries who underwent primary ACLR and had a minimum postoperative follow-up of 12 months. Patients were classified into the cortical button group (n = 26) or the U-staple group (n = 32) according to the initial graft diameter, which strictly dictated the tibial fixation construct documented in the operative report. Both the semitendinosus and gracilis tendons were used in each group. A shorter quadrupled graft construct was prepared in the cortical button group, whereas a longer doubled graft construct was used in the U-staple group. Donor-site pain measured using the visual analog scale (VAS), graft diameter, International Knee Documentation Committee (IKDC) score, Lysholm score, knee range of motion (ROM), Lachman and pivot-shift findings, and graft failure were compared between the groups. Graft failure was defined as magnetic resonance imaging (MRI) evidence of graft discontinuity or insufficiency accompanied by grade 2–3 Lachman laxity or a positive pivot-shift test. Numerical variables were analyzed using the Mann–Whitney U test, whereas categorical variables were compared using the Pearson chi-square or Fisher’s exact test, as appropriate. Results: Donor-site pain was significantly higher in the cortical button group than in the U-staple group [median VAS score: 2.5 (2.0–4.0) vs. 2.0 (0–2.0), respectively; p = 0.007]. Graft diameter was also significantly greater in the cortical button group [10.0 mm (10.0–10.0) vs. 9.0 mm (8.0–9.0); p < 0.001]. In contrast, IKDC scores were significantly higher in the U-staple group [71.0 (51.5–78.0) vs. 60.0 (55.0–62.8); p = 0.017]. No significant differences were observed in Lysholm scores (p = 0.701), knee ROM (p = 0.508), positive pivot-shift findings (11.5% vs. 6.3%; p = 0.648), clinically relevant Lachman laxity (30.8% vs. 18.8%; p = 0.287), or graft failure rates (11.5% vs. 18.8%; p = 0.495). Conclusions: No significant between-group differences were observed in Lysholm scores, knee ROM, clinical stability, or graft failure rates after hamstring autograft ACLR. The U-staple group demonstrated lower donor-site pain and higher IKDC scores, whereas the cortical button group had larger graft diameters, likely reflecting the shorter quadrupled graft configuration. Overall, neither tibial fixation construct showed a consistent advantage across all clinical outcomes. Full article

Copper and lead contamination in loess areas poses a potential threat to soil environmental quality and sustainable land use, while the low permeability, high clay content, and strong buffering capacity of loess often limit the efficiency of conventional electrokinetic (EK) remediation. In this study, a modified activated carbon–carbon fiber (MAC–CF) composite reactive barrier was introduced into an EK remediation system to enhance the soil-phase depletion of Cu and Pb from contaminated loess. The effects of ordinary activated carbon (AC), MAC, CF, and different MAC–CF mixing ratios on current, cumulative electroosmotic flow (EOF), soil pH, electrical conductivity (EC), and potentially toxic metal (PTM) removal were systematically investigated. The conventional AC barrier increased system resistance and inhibited current transmission and EOF. The MAC barrier exhibited enhanced OH⁻ adsorption and buffering capacity, decreasing the cathode-adjacent pH from approximately 9.8 to 8.8. CF incorporation improved barrier conductivity, increasing the peak current from 1.6 A for MAC (100%) to 4.0 A for MAC (25%) + CF (75%), while cumulative EOF increased from approximately 380 to 950 mL. The MAC (25%) + CF(75%) barrier provided the best balance between conductivity enhancement and cathodic alkalization regulation. Sectional Cu removal reached approximately 90% near the anode, whereas Pb removal ranged from approximately 18% to 29%, with a section-weighted mean of about 24.8%. The corresponding residual Pb concentrations (approximately 355–410 mg kg⁻¹) indicate that the system is more effective for Cu and would require additional treatment to meet a conservative agricultural-soil target for Pb. The results support complementary functions of CF in maintaining conductive pathways and MAC in regulating cathodic alkalization. Because Cu and Pb in the spent barrier and electrolyte chambers were not quantified, the proposed precipitation-suppression and migration mechanisms are interpreted from the combined electrochemical, pH, EC, adsorption, and soil-residual evidence rather than from a complete metal mass balance. Full article

Greywater treatment is an essential component of sustainable water management strategies, particularly in regions experiencing water scarcity. This study presents a quantitative comparative evaluation of three conventional inorganic coagulants—aluminum sulfate (Al₂(SO₄)₃), ferric sulfate (Fe₂(SO₄)₃), and ferric chloride (FeCl₃)—for domestic greywater treatment using standardized jar test procedures. The initial turbidity of the greywater was 186 ± 5 NTU. Coagulant performance was assessed based on final turbidity, removal efficiency, and pH variation, with dosages expressed as mg of active metal per liter to ensure comparability. Ferric chloride exhibited the highest turbidity removal efficiency, achieving a maximum removal efficiency of 96.2 ± 0.8% at 68.8 mg Fe/L and reducing turbidity to 7 ± 1 NTU. Ferric sulfate achieved a maximum removal efficiency of 92.5 ± 1.2%, while aluminum sulfate reached 84.9 ± 1.4% under the evaluated conditions. Statistical analysis confirmed significant differences among coagulants at intermediate and high dose ranges (p < 0.05). The results indicate that ferric chloride provides the most effective clarification performance for the tested greywater matrix, while maintaining final pH values within a suitable range for non-potable reuse. This study contributes to coagulant selection for decentralized greywater treatment systems through standardized, quantitative comparison under identical operational conditions. Full article

Background/Objectives: Multiple chronic conditions (MCCs) are highly prevalent among older adults and require effective collaboration between the patient and caregiver. Mutuality, reflecting the quality of the dyadic relationship, is associated with better self-care and health outcomes. However, the Mutuality Scale (MS) has not been validated on patient–caregiver dyads managing MCCs living in a low–middle-income country (LMIC). Aim: This study seeks to evaluate the structural and convergent validity and reliability of the MS among patient–caregiver dyads managing MCCs living in a LMIC. Methods: A cross-sectional study was conducted on MCC patients and their caregiver recruited from community and outpatient settings. The MS, Self-care of Chronic Illness Inventory (SC-CII) and Caregiver Contribution to self-care Inventory (CC-SCCII) were used for measuring mutuality, patient self-care, and Caregiver Contribution (CC) to patient self-care, respectively. Confirmatory factor analysis (CFA) was performed separately for patients and caregivers to evaluate the original four-factor structure of the MS. Convergent validity was examined through correlations with self-care and CC to patient self-care. Reliability was evaluated using composite reliability and the Global Reliability Index for multidimensional scale. Results: A sample of 406 patient–caregiver dyads was examined. Patients had a mean age of 73.9 (±6.2) years. Caregivers had a mean age of 47.8 (±15.5) years. The four-factor structure was supported in both samples, with acceptable model fit (patients: Comparative Fit Index (CFI) = 0.953 and Root Mean Square Error of Approximation (RMSEA) = 0.078; caregiver CFI = 0.945 and RMSEA = 0.085. The second-order CFA supported a hierarchical structure. Patient and caregiver mutuality scores were strongly correlated (r = 0.778, p < 0.01). Higher mutuality was associated with better patient self-care (r = 0.276–0.479) and CC to self-care (r = 0.174–0.556). Reliability indices ranged from 0.70 to 0.91 for patients and 0.66 to 0.89 for caregivers. Conclusions: The findings support the validity and reliability of the MS for assessing mutuality in patients and their caregivers managing MCCs in an LMIC characterized by limited healthcare resources and formal support. Its use provides empirical support for assessing relationship quality and facilitating dyadic care within this vulnerable population. Future longitudinal studies should evaluate its predictive validity, responsiveness, and measurement invariance across different groups and between patient and caregiver. Full article

Prunus mahaleb L. is an important cherry rootstock because of its tolerance to drought and poor soils. Despite its horticultural importance, efficient in vitro multiplication of P. mahaleb remains challenging. Therefore, this study compared conventional agar-solidified culture with the PlantForm^TM temporary immersion system (TIS) for micropropagation of a Bulgarian local form of P. mahaleb. Three basal media, Murashige and Skoog (MS), Woody Plant Medium (WPM), and Driver and Kuniyuki Walnut (DKW), were initially evaluated in both cultivation systems. The media were subsequently supplemented with ascorbic and citric acids to determine whether these antioxidants could further improve culture performance. Compared with agar-solidified culture, the PlantForm^TM TIS significantly enhanced explant proliferation, achieving the highest number of new shoots (6.69 ± 1.82) and biomass production on antioxidant-supplemented DKW medium. The same treatment also resulted in the greatest accumulation of photosynthetic pigments, with maximum total chlorophyll (0.991 ± 0.025 mg g⁻¹ FW) and carotenoid (0.349 ± 0.050 mg g⁻¹ FW) contents. Rooting efficiency ranged from 38.89% to 51.85% and did not differ significantly among treatments, whereas acclimatization was not achieved under the conditions tested. These findings demonstrate that PlantForm^TM TIS combined with antioxidant-supplemented DKW medium provides a promising approach for the multiplication of this P. mahaleb form. However, the rooting and acclimatization stages require further optimization. Full article

Background/Objectives: Traditional medicinal plants play a crucial role in infants’ healthcare in underdeveloped countries and communities where access to modern medicine is limited. In Limpopo, the Vhavenda tribe has a custom of feeding babies as young as a day old with tshiunza, a very light and warm, soft porridge prepared in medicinal plant extracts, believed to help treat various ailments and boost the immune and digestive systems. However, reports of negative side effects, including vomiting, haematuria, renal inflammation and hospitalisations, highlight safety concerns of these traditional practices. This study aimed to profile the chemical composition of soft porridge samples prepared in aqueous extracts of medicinal plants reported to be commonly used in infants’ food in the Venda region of Limpopo; Annona senegalensis (roots), Piliostigma thonningii (leaves), Carissa edulis (roots) and Bauhinia galpinii (leaves). Methods: Ultrahigh-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-qTOF-MS) was used for metabolic profiling, followed by putative compound identification using feature-based molecular networking and a compound fragmentation predictor tool, SIRIUS. To evaluate the toxicity of these plants, a cytotoxicity assay was conducted using plant extracts on African monkey kidney cells. Results: Different classes of polyphenols, including flavonoids (flavan-3-ols and flavonols) and hydroxycinnamoyl amides, were among the dominant compounds putatively identified in the methanolic extracts of soft porridge prepared from the four plant extracts. A. senegalensis aqueous extracts were inactive (IC₅₀ > 500 µg/mL, 55.57% viability at 500 µg/mL), while P. thonningii was non-cytotoxic (105–132% viability within the tested concentration range). Conclusions: Although no toxic compounds were identified and no cytotoxic potential was observed in the tested plant extracts, this does not translate to the safe use of medicinal plants in infants’ food. Therefore, future studies should conduct pharmacological and toxicological evaluations to better understand the potential risks of these plant extracts to infant health. Full article

Machine learning (ML) algorithms can be used to extract clinically meaningful information from movement data captured by inertial measurement units (IMUs), but many human activity recognition (HAR) pipelines are developed on large laboratory datasets that may not reflect small, heterogeneous, real-world samples. The purpose of this study is to systematically compare the accuracy of multiple ML models, feature sets (both simple and expanded), class balancing strategies, null and transition period handling techniques, and sensor configurations for recognizing a set of four everyday activities extracted from IMU time series data from an age-diverse population. Six ML classifiers were trained and tested: multilayer perceptron, random forest, k-nearest neighbors, logistic regressor, CatBoost, and gaussian naive bayes. These approaches were used in a pipeline with differing sampling techniques including the synthetic minority oversampling technique or random undersampling, and feature handling steps including principal component analysis or a Select-From-Model metatransformer. Additionally, two deep learning methods, DeepConvLSTM and ResGCNN, were trained and tested. Accuracy, precision, recall, and area under the receiver operating characteristic curve were compared to a dummy classifier as a benchmark approximation to chance performance. All pipelines performed better than the dummy classifier, with model accuracy ranging between 0.427 and 0.644. This study demonstrated the ability of several ML algorithms to properly recognize a set of functional activities using limited IMU data from both children and adults. Full article

Background: Large language models (LLMs) are increasingly deployed in socially sensitive contexts, raising concerns about how their outputs reflect or reproduce socially aversive response patterns. Prior research has focused on socially desirable traits (e.g., the Big Five), while less attention has been given to the Dark Triad—Machiavellianism, narcissism, and psychopathy. Methods: This exploratory study applies a psychometric probing approach using the Short Dark Triad (SD3) as a structured questionnaire to analyze response patterns in 12 LLMs. Through controlled persona prompting (gender, age, religion), more than 540,000 responses were generated across model–persona–item observations. Outputs were scored using standard psychometric procedures and compared with pooled human SD3 reference values using Hedges’ g as an interpretive benchmark. Results: Across models, Machiavellianism-related scores tend to be lower than human references, narcissism-related scores slightly higher, and psychopathy-related scores largely within the human range. Persona prompting produces systematic but uneven effects: gender has minimal impact, age yields small shifts, and religious framing leads to the strongest and most consistent decreases in socially aversive response patterns. However, observed differences showed notable heterogeneity across models. Conclusions: The findings should be understood as response patterns shaped by context and specific prompting conditions. Our findings suggest that persona effects reflect normative activation, not identity simulation. Persona prompts seem to trigger patterns in the training data rather than consistent, identity-specific traits. Overall, the study highlights both the potential and limitations of psychometric-style probing for evaluating LLM behavior and underscores the importance of prompt context in shaping model outputs. Full article

During coal beneficiation in a gas–solid fluidized bed, coarse feed particles act as moving intruders whose size and shape can reorganize the local gas–solid flow field. This study combines particle-surface differential-pressure measurements, synchronized visual observation, pressure-signal analysis, and Eulerian–Eulerian CFD to distinguish the disturbance caused by the feed particle from the background fluctuation of the dense medium. Unlike studies that characterize only the global bed pressure drop, the present work resolves the pressure response on the upper and lower surfaces of individual 13–50 mm feed particles and links it to bubble attachment, bypassing, and medium-particle recirculation. Within a fluidization-number range of 1.0–1.6, the disturbance intensified with feed-particle size: the 50 mm particle produced the largest upper–lower pressure difference and pressure-drop fluctuations exceeding 100 Pa. Particle shape also altered the local flow topology; the flat lower face of the block-shaped particle promoted a persistent gas cushion, localized pressure concentration, and medium recirculation; whereas, the spherical particle generated a comparatively symmetric disturbance. Synchronized images confirmed the transition from intermittent small bubbles near minimum fluidization to bubble coalescence and vigorous recirculation at higher gas velocities. At N = 1.2, the CFD results reproduced the experimental size and shape rankings, with case-by-case relative errors of 4.7–7.0% and a mean absolute relative error of 5.5%. Coherence analysis further showed that the influence of a large particle decayed with distance and produced a stepwise axial distribution of local flow states. These results provide a particle-scale basis for controlling feed-induced disturbances in gas–solid fluidized-bed separation. Full article

The transition from conventional silica nanoparticle (SiNP) production based on purified alkoxysilanes and high-temperature flame hydrolysis of silicon tetrachloride to renewable and waste-derived silicon resources requires more than precursor substitution. It requires a mechanistic understanding of how feedstock mineralogy, silicon speciation, impurity chemistry, and processing history propagate through dissolution, nucleation, condensation, gelation, aging, drying, and pore evolution to determine material performance, environmental burden, and manufacturing feasibility. Although previous reviews have established the technical feasibility of producing silica from secondary resources, their predominant organization by feedstock, synthesis route, or application provides limited ability to explain why nominally similar processes generate materials with markedly different structural and functional properties. This review addresses these through a resource-pull, feedstock-to-function framework that links resource chemistry and process design to critical material attributes, application-specific specifications, sustainability, and scale-up requirements. Agricultural residues, industrial by-products, geothermal resources, waste glass, and fluorosilicate streams are critically compared according to silicon form and phase, reactivity, impurity profile, compositional variability, purification demand, and attainable product quality. Particular attention is given to waste-derived alkaline silicate systems, in which molecular, oligomeric, and colloidal silica coexist and therefore require characterization beyond bulk SiO₂ concentration. Established and emerging processing strategies, including controlled combustion and alkaline extraction, alkali fusion, ambient-pressure drying, microwave and mechanochemical activation, biogenic and biomimetic templating, and continuous processing, are evaluated according to their mechanistic effects, technological maturity, structural control, and demands for energy, reagents, water, solvents, effluent treatment, and capital. Across these routes, gelation and aging emerge as critical transfer stages through which feedstock composition is translated into network connectivity, pore architecture, shrinkage behavior, and ultimately functional performance. Evidence from secondary-source aerogels further shows that properly controlled waste-derived systems can attain BET surface areas of approximately 350–500 m² g⁻¹, within the textural range of many alkoxide-derived materials, indicating that feedstock variability, impurity management, and process control are more important constraints than an inherently lower performance ceiling. On this basis, this review proposes a minimum evidence framework comprising feedstock traceability, intermediate-speciation and colloidal characterization, silicon mass balance, gelation and aging metrics, application-specific qualification criteria, performance-normalized life cycle and techno-economic assessment, process analytical control, and staged pilot validation. Collectively, these principles provide a mechanistically grounded basis for moving sustainable silica synthesis beyond isolated proof-of-concept demonstrations toward reproducible, scalable, application-matched, and commercially credible manufacturing platforms. Full article

Adhesive capsulitis is characterized by shoulder pain, stiffness, and limited range of motion. Although multimodal rehabilitation is commonly used, it is unclear which combination of physiotherapy interventions is optimal. The aim of this exploratory study was to compare the short-term effects of TECAR therapy combined with proprioceptive neuromuscular facilitation (PNF) with those of standard physiotherapy in women with stage II adhesive capsulitis. This was a prospective, longitudinal, non-randomized, and exploratory study in which participants were assigned either the TECAR + PNF group or the standard physiotherapy group. Both intervention groups were given treatment three times a week for four weeks. Pain intensity and upper-limb disability were measured using the Visual Analog Scale (VAS) and the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Shoulder flexion, abduction, internal rotation and external rotation were measured using goniometry. Within-group changes were analyzed with the Wilcoxon signed-rank test, and exploratory baseline-adjusted analyses were conducted with ANCOVA. Both groups showed statistically significant improvements in pain and disability as a result of treatment. The median reduction on the VAS was about 5.00 points in the TECAR + PNF group and 2.00 points in the standard physiotherapy group. The median DASH scores fell by about 43.25 points and 16.00 points, respectively. Exploratory ANCOVA models showed that the TECAR + PNF group had more favourable adjusted VAS and DASH scores after treatment. Nevertheless, the groups differed at baseline in abduction, internal rotation, and external rotation, and a full pre–post analysis of changes in range of motion was not available. Therefore, the mobility results cannot be regarded as providing evidence of treatment superiority. We can conclude that in this small, non-randomised pilot study, the combination of TECAR and PNF led to greater short-term reductions in pain and upper-limb disability compared with standard physiotherapy. Nevertheless, these findings are still only preliminary and hypothesis-generating, and it is essential to carry out larger, adequately powered randomised controlled trials with concealed allocation, balanced baseline characteristics, complete analyses of changes in range of motion, and longer follow-up periods in order to confirm their clinical relevance and determine their comparative effectiveness. Full article