Search Results (1,982)

This study investigates the tri-objective optimization of underground metro station structures, considering structural reliability, life-cycle economic cost, and annualized carbon emissions simultaneously. Using a representative metro station in Guangzhou as a case study, a multi-objective optimization framework is developed. The model defines structural failure probability, discounted life-cycle cost, and average annual carbon emissions as the primary objectives, with decision variables including concrete strength, cover thickness, the use of epoxy-coated reinforcement, and various maintenance/repair strategies. Material quantities are calculated through Building Information Modeling (BIM), while cost–carbon relationships are derived from industry price data and carbon emission factors. An improved multi-objective particle swarm optimization algorithm (OMOPSO) is used to derive the Pareto-optimal front. Case study results show that increasing cover thickness significantly improves durability and reduces carbon emissions with only moderate cost increases. In contrast, epoxy-coated reinforcement is excluded from the Pareto set due to its high cost under the given conditions. To facilitate practical decision-making, a weight-based solution selection method is introduced, and sensitivity analyses are performed to assess the model’s robustness. The study concludes by emphasizing the framework’s applicability and limitations: the findings are specific to the case context and require recalibration for use in other sites or construction practices. This research contributes by integrating durability, cost, and carbon considerations into an engineering-level optimization workflow, providing valuable decision support for sustainable metro station design. Full article

Low-disturbance liquid manure injection is increasingly important for sustainable soil management because it reduces residue burial, minimizes surface disruption, and lowers energy demand during application. However, the performance of low-disturbance shanks has not been systematically optimized, and their interaction with soil remains poorly quantified. This study developed an integrated discrete element method (DEM)–experimental framework to evaluate and optimize the performance of a purpose-built injector shank featuring a 45° rake angle, 25 mm thickness, and 110 mm width. The framework aimed to identify operating conditions that balance soil disturbance and energy efficiency. A DEM soil model was constructed using mechanical properties obtained from laboratory characterization tests and validated against soil bin experiments measuring draft force and soil rupture area across five working depths (100–250 mm) and three travel speeds (350–450 mm/s). The calibrated model showed strong agreement with experimental observations, yielding mean absolute relative errors of 1.7% for draft force and 6.2% for rupture area. Following validation, a multi-objective optimization was performed to minimize draft force while maximizing soil rupture, two key indicators of energy demand and injection effectiveness. Optimization results identified the most favorable operating parameters at a forward speed of 450 mm/s and an injection depth of 150 mm, achieving a desirability score of 0.884. The integrated DEM–experimental framework demonstrated reliable predictive capability and enables virtual testing of soil–tool interactions prior to field implementation. This study provides a scientifically grounded approach for improving injector shank operation and supports sustainable manure management by identifying settings that achieve adequate soil disruption while reducing energy consumption. Full article

The stability of underground excavations is a critical factor in the safety and efficiency of mining operations, particularly in structurally complex and geomechanically variable rock mass. This study presents a comparative evaluation of empirical and numerical methods for the design of tunnel support systems in the Gilar underground mine, located in the Gedabek Contract Area of Azerbaijan. To validate and optimize the empirical Q-system-based support designs, Finite Element Method (FEM) simulations were conducted using RS2 software. These simulations enabled the modeling of stress distribution, deformation, and support–rock interaction under in situ conditions. Critical sections along the main ramp were analyzed in detail to determine safety factors during excavation and post-support installation. The study reveals that, although the Q-system provides a practical and time-efficient method for support selection, it may underestimate the reinforcement required in highly fractured or low-strength zones. Numerical modeling proved to be essential in identifying zones with low strength factors and in optimizing support configurations by adjusting rockbolt spacing and shotcrete thickness. The hybrid approach adopted in this study—empirical classification followed by numerical verification and optimization—demonstrated significant improvements in long-term tunnel stability. This research highlights the importance of integrating empirical and numerical approaches for robust ground support design in underground mining. The proposed methodology not only enhances the accuracy of support recommendations but also provides a more reliable basis for decision-making in complex geological settings. The results are particularly relevant for deep and geologically active mines requiring long-term stability of access tunnels. Full article

Background: Resistance training has recently focused more on a high- vs. low-load training approach, suggesting heavier loads optimize strength adaptations through maximal recruitment of motor units, whereas lower loads stimulate a greater hypertrophy response. The purpose of this investigation was to examine and determine significant differences in muscle thickness, strength, and hormonal markers over nine weeks of high- or low-load resistance training. Methods: Seventeen recreationally-trained males were recruited for this study (M_age = 20.4 ± 2.7 years). Participants were split into training with high-loads (85% 1-RM; n = 8) or low-loads (30% 1-RM; n = 9) completing 3 whole-body training sessions per week for 9 weeks. Each session included three working sets per exercise of repetitions to failure. Measures were collected at baseline and every three weeks after of muscle thickness (biceps brachii, triceps brachii, pectoral major, rectus femoris, and biceps femoris) and salivary hormones (basal and acute post-exercise testosterone and cortisol). RM-ANOVAs were conducted to analyze changes in hypertrophy and the hormones, with significance set at p < 0.05. Results: Muscle thickness increased significantly over time for all sites (p < 0.05), with no significant group × time interactions except for the triceps brachii (p = 0.04). There were no significant changes in basal hormone levels or changes from basal to immediately post exercise (p > 0.059). The high-load group showed greater increases in 1-RM following the training program. Conclusions: Our results demonstrate similar hypertrophy regardless of training volume and training load, but greater increases in strength in the high-load group. Hormonal data revealed no significant changes in basal cortisol and testosterone, suggesting similar stress and recovery. While nonsignificant for differences pre-post in either marker, the pattern of a slight decrease in testosterone may be an effect of receptor uptake, and additional monitoring over a longer time interval should be used to track the changes over a full recovery window. Full article

Background/Objectives: Teledermatology has transformed access to dermatologic care, yet its association with melanoma prognostic parameters and diagnostic pathways in tertiary settings remains incompletely characterized. To compare the clinicopathologic profile of melanomas diagnosed under face-to-face consultation (2019) versus teledermatology-based referral (teleconsultation) (2022). Methods: A retrospective observational study comparing two patient cohorts: those diagnosed with melanoma via in-person consultation in 2019, and those diagnosed through teleconsultation in 2022. These years were selected to reflect the structural shift in care delivery models before and after the COVID-19 pandemic, during which teledermatology was formally implemented. Sociodemographic, clinical, and histopathological variables were collected. A multivariable logistic regression model assessed variables associated with being diagnosed in the 2022 teledermatology cohort versus the 2019 face-to-face cohort. Statistical analyses were performed using R (v. 4.4.3). Results: A total of 151 patients were included (89 in-person in 2019, 62 via teleconsultation in 2022). Multivariable analysis identified three variables independently associated with being diagnosed via teleconsultation. Increasing Breslow thickness was inversely associated with teleconsultation diagnosis (OR 0.60 per 1 mm increase; 95% CI 0.40–0.91; p= 0.017). Similarly, the presence of histologic regression (OR 0.28; 95% CI 0.09–0.90; p = 0.032) and immunosuppression (OR 0.08; 95% CI 0.008–0.86; p = 0.037) were inversely associated with teleconsultation diagnosis. No significant associations were found for sex, age, tumor location, ulceration, mitosis, or clinical stage. Conclusions: In this retrospective single-center comparison of two care models, melanomas diagnosed through teleconsultation in 2022 were associated with a more favorable clinicopathologic profile at diagnosis than those diagnosed via face-to-face consultation in 2019. These findings support the role of teledermatology-based referral pathways in facilitating timely melanoma assessment, although causal inference is limited by the observational design. Full article

Laser powder bed fusion (LPBF) is the best suited technology to manufacture temperature-resistant Ti-6Al-2Sn-4Zr-6Mo parts with complex geometrical features for high-end applications. Improving printing accuracy by reducing the layer thickness (t) generally requires repeating a tedious and time-consuming process optimization routine. To simplify this endeavour, the present work proposes three process equivalence criteria allowing to transfer optimized process conditions from one printing parameter set to another. This approach recommends keeping the volumetric laser energy density (VED) and hatching space-to-layer thickness ratio (h/t) constant, while adjusting the scanning speed (v) and hatching space (h) accordingly. To validate this approach, Ti6246 parts were printed with 50 µm and 25 µm layer thicknesses, while keeping VED = 100 J/mm³ and h/t = 3 constant for both cases. The printed samples were analyzed in terms of their density, microstructure and mechanical properties, as well as the geometric compliance of wall-, gap- and channel-containing artefacts. Highly dense samples exhibiting comparable microstructures and mechanical properties were obtained with both parameters sets investigated. However, they induced markedly differing geometric characteristics. Notably, using 25 µm layers allowed printing walls as thin as 0.2 mm as compared to 1.0 mm for 50 µm layers. Full article

Background/Objectives: The influence of the vitreoretinal interface on neovascular age-related macular degeneration (nAMD) remains poorly characterized. Most previous studies relied solely on macular optical coherence tomography (OCT), which provides limited information about global posterior vitreous detachment (PVD). This study evaluated (1) whether ultrasonography-defined PVD status differs between nAMD eyes and healthy controls, and (2) whether baseline PVD influences macular neovascularization (MNV) phenotype and functional outcomes following anti-vascular endothelial growth factor (anti-VEGF) therapy. Methods: In this prospective longitudinal study, treatment-naïve nAMD eyes and population-based healthy controls underwent dynamic B-scan ultrasonography and spectral-domain OCT. PVD was categorized as absent, partial, or complete. nAMD eyes received intravitreal aflibercept according to a treat-and-extend protocol and were followed for 12 months. Structural parameters—including subretinal fluid (SRF), intraretinal fluid (IRF), and central foveal thickness—along with best-corrected visual acuity (BCVA) were recorded. A multivariable linear regression model was performed to assess whether PVD independently predicted BCVA gain after adjusting for age, baseline BCVA, MNV subtype, SRF, atrophy, and number of injections. Results: Absence of PVD was significantly more frequent in nAMD eyes than in controls (p < 0.001), whereas complete PVD prevalence was comparable. In nAMD, absence of PVD was associated with a higher prevalence of MNV type 2 (p = 0.032), while partial/complete PVD correlated with type 1 lesions. After 12 months, eyes without PVD achieved the greatest visual improvement (mean BCVA gain +0.34 ± 0.26), outperforming eyes with complete PVD (p = 0.026). A multivariable model confirmed that absence of PVD was an independent predictor of greater BCVA gain (β = −0.27; 95% CI −0.42 to −0.12; p = 0.0008). Eyes with complete PVD required more injections (p = 0.046). SRF and foveal-thickness reductions occurred across groups, whereas IRF changes were similar. Conclusions: Ultrasonography-defined PVD status differs markedly between nAMD and healthy eyes and independently influences neovascular phenotype and functional response to anti-VEGF therapy. These findings underscore the physiological importance of the vitreoretinal interface and support the use of ocular ultrasonography as an adjunct tool for assessing global vitreous status in selected nAMD settings. Full article

This literature review systematizes current data on the development of triploid seedless hybrids in the Cucurbitaceae Juss family. The absence of seeds simplifies the consumption and industrial preparation of products from cucurbits. In addition, triploids showed larger plant habitus, field resistance to infections, extended shelf life, and higher fruit quality. Phenotypic differences in polyploids can stem from altered chromatin organization and gene regulation, as the nucleus must accommodate a doubled chromosome set. The triploid watermelon cultivation method developed in 1951 failed to gain traction among other crops in the gourd (Cucurbitaceae) family. The challenges of triploid seed production and use include the need for the development of tetraploid and diploid parental lines, as well as bypassing the problem of the low viability of tetraploid parent pollen and the issue of thick seed coats and underdeveloped embryos in triploids. The research findings presented in this review can be applied to the development of triploid seedless hybrids for other members of the Cucurbitaceae family. Full article

This study introduces a model-free reinforcement learning framework based on Q-Learning (QLA) for the multi-objective optimization of Selective Laser Melting (SLM) process parameters for Inconel 718. To efficiently handle the limited experimental dataset, a tabular Q-Learning approach was implemented, in which each parameter combination was treated as a discrete state and every possible transition as an action. Four key process variables laser power (P), scan speed (S), layer thickness (T), and hatch spacing (H) were optimized for two output responses: relative density (RD) and Vickers hardness (VH). The Q-Learning agent iteratively explored various parameter combinations, observed the resulting material properties, and continuously updated its policy to converge toward optimal conditions. The optimal parameter set identified by the framework was P = 270 W, S = 800 mm/s, H = 0.1 mm, and T = 0.08 mm. Despite relying on only 16 experimental trials, the model achieved exceptionally low prediction errors of 0.0503% for RD and 0.0857% for VH, demonstrating substantial reductions in both experimental effort and material consumption. The results confirm that reinforcement learning can autonomously and effectively identify optimal SLM parameter settings, highlighting its strong potential to enhance precision, efficiency, and overall quality in the additive manufacturing of metallic components. Full article

Background: The clinical research laboratory plays a pivotal role in the execution of clinical studies. The accurate and consistent registration of patients is dependent on the competent use of laboratory equipment and manual techniques by technicians, ensuring the reliability of the data collected. To support these activities, the Groupe de Recherche Action en Santé (GRAS) has been registered with the College of American Pathologists (CAP) and the Clinical Laboratories Services (CLS) in Johannesburg, South Africa, for external proficiency testing (EPT) of its laboratory, as part of our commitment to quality assurance. The following report details the performance achievements over the past five years. Methods: Proficiency testing (PT) samples are dispatched to GRAS Lab three times a year (quarterly) and the results are generally returned within two to three weeks. In the field of parasitology, challenge specimens were prepared as follows: thick and thin blood films were stained with Giemsa and mounted with strips to protect them for multiple uses. Photographs, also known as whole slide images (WSIs), were also taken. For the biochemistry and haematology tests, a set of five samples were received for processing. All evaluations were carried out in accordance with the GRAS laboratory’s internal procedures. Results: The CAP laboratory’s performance in terms of the diagnosis of malaria and other blood parasites from 2020 to 2024 was 97.3% accurate (ranging from 93.33% to 100%), with 93.33%, 100%, 100%, 93.33% and 100% achieved in 2020, 2021, 2022, 2023 and 2024, respectively. The number of microscopists evaluated annually has been subject to variation according to operational staff at the time of evaluation. A total of 31 microscopists were enrolled in the CLS PT scheme, of which 73.9% were classified as ‘experts’ and 19.2% as ‘reference’ microscopists. In the field of haematology, the PT demonstrated 100% accuracy over the four-year study period. This outcome is indicative of the high-performance levels exhibited by the automated systems under scrutiny and the comparable nature of the data produced by these systems. The same trend was observed in the biochemistry PT results, with an overall score of 92.12%, ranging from 78% to 100%. Conclusions: Proficiency testing has been shown to be an effective tool for quality assurance in laboratories, helping to ensure the accuracy of malaria and other blood parasite diagnoses made by microscopists, as well as the results generated by automated systems. It has been instrumental in assisting laboratories in identifying issues related to test design and performance. Full article

Background: Objective, reproducible assessment of deep cervical muscle mechanics is clinically relevant, yet the reliability of shear-wave elastography (SWE) for the longus colli (LC) has not been established. Therefore, the aim of this study was to determine intra- and inter-examiner reliability of LC stiffness measured by SWE under a tightly standardized protocol in patients with mechanical neck pain. Methods: A longitudinal reliability study was conducted. Adults suffering from neck pain for ≥6 months were recruited. Two examiners (with different levels of experience) acquired bilateral LC images using fixed presets. The SWE region of interest covered the full muscle thickness (excluding fascia) to measure the LC shear-wave speed and Young’s modulus. Intraclass correlation coefficients (ICCs), standard error of measurement and minimal detectable changes were computed. Results: Nineteen participants with neck pain completed imaging (left and right sides analyzed). Inter-examiner agreement was good to excellent for single measurements (ICC_3,2 > 0.818) and improved when averaging two acquisitions (ICC_3,2 > 0.866). Intra-examiner repeatability was good to excellent for the novel examiner (ICC_3,1 > 0.891) and excellent for the experienced examiner (ICC_3,1 > 0.973). No meaningful stiffness differences by sex or side were observed in this sample (p > 0.05). Conclusions: A standardized SWE workflow yields reproducible LC stiffness measurements in mechanical neck pain. For longitudinal use, keep a single operator when feasible; in multi-examiner settings, average at least two acquisitions per side to enhance sensitivity to true change. Full article

Background/Objectives: Intestinal ultrasound (IUS) is increasingly used to monitor ulcerative colitis (UC), but its predictive value remains unclear. This systematic review evaluated the ability of IUS parameters and scores to predict short- and long-term treatment response, remission, and adverse outcomes in hospitalized and outpatient UC populations. Methods: A systematic review was conducted according to Cochrane and PRISMA guidelines. MEDLINE and Embase were searched for prospective studies assessing IUS as a predictor of clinical or endoscopic response, remission, relapse, or adverse outcomes in adult UC. Two reviewers independently performed screening, data extraction, and QUADAS-2 assessment. Results: Eighteen prospective studies were included: eleven outpatient studies and seven involving hospitalized patients treated with intravenous corticosteroids (IVCS). In hospitalized patients, bowel wall thickness (BWT) was the most consistent predictor of treatment failure, rescue therapy, colectomy, and clinical response. Baseline BWT showed variable performance, but once IVCS was initiated, early BWT change within 48–72 h was the strongest marker of disease trajectory. Non-responders had higher BWT and smaller reductions. A BWT ≥ 4 mm, absolute reduction ≤ 1 mm, or relative reduction ≤ 20% at 48 h reliably identified patients needing rescue therapy (area under the curve (AUC) values of 0.77 (95% confidence interval (CI) 0.71–0.74), 0.71 (95% CI 0.56–0.86), and 0.74 (95% CI 0.60–0.88)). Colectomy risk was similarly predicted: BWT < 3 mm at 48 h was associated with no colectomies, whereas BWT ≥ 4 mm or persistently elevated BWT at day 6 markedly increased risk (Odds ratio (OR) 9.5-fold (95% CI 1.4–64.0) and OR 8.3 (95% CI 1.7–40.0), respectively). Other sonographic features (loss of haustration, increased vascularity) added supplementary but less consistent value. In outpatients, BWT also demonstrated the strongest predictive accuracy. BWT ≤ 3.6 mm at 2 weeks and <3.0 mm at 6 weeks were associated with early endoscopic remission (area under the receiver operating characteristic (AUROC) of 0.87 (95% CI 0.71–1.00) and 0.82 (95% CI 0.63–1.00), respectively). Dynamic changes with ≥23–25% relative reduction predicted clinical or endoscopic response (AUROC of 0.81 (95% CI 0.61–1.00) and OR of 13.9 (95% CI 1.13–1986.85), respectively). Persistent BWT > 3.5 mm or minimal reduction (<20% or <1 mm) indicated a low likelihood of long-term remission. Composite vascularity-based indices, particularly the Milan Ultrasound Criteria (MUC), strengthened prediction: MUC ≤ 4.3 or ≥2-point reduction at 12 weeks predicted long-term remission (AUROC 0.88 (95% CI 0.750–0.952) and 0.82 (95% CI 0.68–0.91), respectively), while MUC ≥ 7.7 indicated high risk of treatment failure or colectomy (AUROC 0.77 (95% CI: 0.73–0.82)). Conclusions: Across clinical settings, BWT consistently emerged as the strongest IUS predictor of UC treatment outcomes. Early BWT change within 48–72 h in hospitalized patients and absolute BWT values at 2–6 weeks in outpatients showed high predictive accuracy for response, remission, and colectomy. Composite indices incorporating vascularity further improved prediction. These findings support the incorporation of IUS into early treatment-response algorithms and underscore the need for standardized cut-offs and multicenter validation. Full article

Intermetallic Fe₃Al-based alloys reinforced with Laves-phase precipitates are emerging as potential replacements for conventional high-alloy steels and possibly polycrystalline Ni-based superalloys in structural applications up to 700 °C. Their impressive mechanical properties, however, are offset by limited fabricability and poor machinability due to their severe brittleness. High tool wear during finish-machining, which is still required for components such as turbine blades, remains a key barrier to their broader adoption. In contrast to conventional manufacturing routes, additive manufacturing offers a viable solution by enabling near-net-shape manufacturing of difficult-to-machine iron aluminides. In the present study, laser powder bed fusion was used to produce an Fe-25Al-1.5Ta intermetallic containing strengthening Laves-phase precipitates, and the porosity, microstructure and phase composition were characterized as a function of the process parameters. The results showed that preheating the build plate to 650 °C effectively suppressed delamination and macrocrack formation, even though noticeable cracking still occurred at the high scan speed of 1000 mm/s. X-ray tomography revealed that samples fabricated with a lower scan speed (500 mm/s) and a higher layer thickness (0.1 mm) contained larger, irregularly shaped pores, whereas specimens printed at the same volumetric energy density (40 J/mm³) but with different parameter sets exhibited smaller fractions of predominantly spherical pores. All samples contained mostly elongated grains that were either oriented close to <001> relative to the build direction or largely texture-free. X-ray diffraction confirmed the presence of Fe₃Al and C14-type (Fe, Al)₂Ta Laves phase in all samples. Hardness values fell within a narrow range (378–398 HV10), with only a slight reduction in the specimen exhibiting higher porosity. Full article

Background: Geohelminthiasis and malaria are major public health problems in Kinshasa. Pregnant women are particularly vulnerable to these conditions due to their weakened immunity, with severe complications such as maternal anemia and low birth weight. This study assessed the prevalence and associated factors of geohelminth–malaria co-infection. Methods: A cross-sectional study was conducted in two hospitals in Kinshasa, Democratic Republic of the Congo, which included 336 pregnant women. The lab analyses included thick smears for malaria, stool examinations for geohelminths, and hemoglobin measurements. Multivariate logistic regression was used to identify associated variables, with a significance level set at p < 0.05. Results: Geohelminth–malaria co-infection was observed in 5.7% of pregnant women, while the prevalence of geohelminthiasis alone was 7.7%. Ascaris lumbricoides was the most frequent parasite (6.3%), followed by Trichuris trichiura (1.5%) and Ancylostoma duodenale (0.3%). The third trimester was associated with a significantly increased risk of co-infection and geohelminthiasis (ORa = 5.8; 95% CI: 1.36–9.23; p = 0.0077). No significant association was found between co-infection and maternal anemia. Conclusions: Although co-infection prevalence was low in Kinshasa, the third trimester is a risk period. Systematic screening and integrated management during pregnancy are recommended. Full article

Vegetation concrete is a composite material integrating plant growth and concrete technology. In this study, solid waste materials (phosphogypsum and recycled aggregates) were utilized to prepare vegetation concrete. Semi-hydrated phosphogypsum (HPG) was used to replace ordinary Portland cement as a cementitious material in a gradient manner, while recycled coarse aggregates (RCAs) fully replaced natural crushed stone. The basic properties of phosphogypsum–recycled aggregate-based vegetation concrete were analyzed, and X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the hydration products of vegetation concrete with different mix ratios. The results indicated that replacing cement with HPG exerted a significant alkali-reducing effect and provided favorable cementitious strength. When the porosity was 24% and the HPG content was 50%, the vegetation concrete exhibited optimal performance: the 28-day compressive strength reached 12.3 MPa, and the pH value was 9.7. Recycled aggregates had a minimal impact on strength. When 0.5% sodium gluconate was added as a retarder, the initial setting time was 97 min and the final setting time was 192 min, which met construction requirements with little influence on later-stage strength. Microscopic analysis revealed that the early strength (3d–7d) of vegetation concrete was primarily contributed by CaSO₄·2H₂O crystals (the hydration product of HPG), while the later-stage strength was supplemented by C-S-H (the hydration product of cement). Planting tests showed that Tall Fescue formed a lawn within 30 days; at 60 days, the plant height was 18 cm and the root length was 6–8 cm. Some roots grew along the sidewalls of concrete pores and penetrated the 5 cm thick vegetation concrete slab, demonstrating good growth status. Full article