Search Results (7,945)

Background: Obesity affects over one billion people globally. Bariatric surgery is the most effective long-term intervention for severe obesity. However, postoperative outcomes can vary considerably, with such factors as baseline fitness and cardiorespiratory reserve influencing surgical outcomes. This systematic review aimed to evaluate the effects of preoperative exercise or physical activity, compared to standard care or no intervention, on preoperative fitness parameters and perioperative surgical outcomes in adults with obesity undergoing metabolic and bariatric surgery. Methods: A systematic review was conducted in accordance with the recommendations of the Cochrane Handbook and the PRISMA guidelines. Randomized controlled trials, non-randomized controlled trials, and cohort studies with control groups evaluating preoperative exercise interventions were included. Two independent reviewers conducted study selection, data extraction, and risk of bias assessment using Cochrane tools. Meta-analyses were performed using random effects models, with standardized mean differences calculated for continuous outcomes. Evidence certainty was assessed using the GRADE approach. Results: A total of 15 studies, including 1378 participants, were identified for qualitative synthesis, with 12 contributing data for quantitative meta-analysis. Preoperative exercise interventions significantly improved six-minute walk test distance (SMD 2.01; 95% CI: 0.51 to 3.50; p = 0.009) and VO₂ peak (SMD 1.02; 95% CI: 0.52 to 1.51; p < 0.0001). BMI reduction was significant (SMD −0.96; 95% CI: −1.75 to −0.16; p = 0.02), while weight change was not statistically significant (SMD −0.81; 95% CI: −1.72 to 0.09; p = 0.08). One study reported a reduction in hospital length of stay of 0.64 days (95% CI: −0.86 to −0.42; p < 0.00001). Evidence certainty was rated as very low to low across all outcomes. Conclusions: Preoperative exercise interventions have been shown to significantly improve cardiorespiratory fitness in bariatric surgery candidates, with large effect sizes for functional capacity measures. Despite the low certainty of the evidence, these findings suggest that supervised exercise programs should be incorporated into the preoperative care of bariatric surgery patients. Full article

As the core component of aircraft systems, aeroengines require accurate Remaining Useful Life (RUL) prediction to ensure flight safety, which serves as a key part of Prognostics and Health Management (PHM). Traditional RUL prediction methods primarily fall into two main categories: physics-based and data-driven approaches. Physics-based methods mainly rely on extensive prior knowledge, limiting their scalability, while data-driven methods (including statistical analysis and machine learning) struggle with handling high-dimensional data and suboptimal modeling of multi-scale temporal dependencies. To address these challenges and enhance prediction accuracy and robustness, we propose a novel hybrid deep learning framework (CLSTM-TCN) integrating 2D Convolutional Neural Network (2D-CNN), Long Short-Term Memory (LSTM) network, and Temporal Convolutional Network (TCN) modules. The CLSTM-TCN framework follows a progressive feature refinement logic: 2D-CNN first extracts short-term local features and inter-feature interactions from input data; the LSTM network then models long-term temporal dependencies in time series to strengthen global temporal dynamics representation; and TCN ultimately captures multi-scale temporal features via dilated convolutions, overcoming the limitations of the LSTM network in long-range dependency modeling while enabling parallel computing. Validated on the NASA C-MAPSS data set (focusing on FD001), the CLSTM-TCN model achieves a root mean square error (RMSE) of 13.35 and a score function (score) of 219. Compared to the CNN-LSTM, CNN-TCN, and LSTM-TCN models, it reduces the RMSE by 27.94%, 30.79%, and 30.88%, respectively, and significantly outperforms the traditional single-model methods (e.g., standalone CNN or LSTM network). Notably, the model maintains stability across diverse operational conditions, with RMSE fluctuations capped within 15% for all test cases. Ablation studies confirm the synergistic effect of each module: removing 2D-CNN, LSTM, or TCN leads to an increase in the RMSE and score. This framework effectively handles high-dimensional data and multi-scale temporal dependencies, providing an accurate and robust solution for aeroengine RUL prediction. While current performance is validated under single operating conditions, ongoing efforts to optimize hyperparameter tuning, enhance adaptability to complex operating scenarios, and integrate uncertainty analysis will further strengthen its practical value in aircraft health management. Full article

Background: The addition of chlorhexidine in dental restorative materials is a promising strategy to reduce the recurrence of tooth decay lesions. However, the main challenge is to develop materials with antimicrobial activity in the long term. Objective: This study analyses the effect of filler type and concentration of resin composites supplemented with chlorhexidine loaded in carrier montmorillonite particles (MMT/CHX) regarding their chemical, physical, and short- and long-term antimicrobial proprieties. Materials: Experimental composites were synthesized with 0, 30, or 60% filler in two ratios, 70/30 and 80/20, of barium glass/colloidal silica, respectively, and 5 wt% MMT/CHX. Conversion was measured using near Fourier-transform infrared spectrometry. Sorption and solubility were determined by specimen weight before and after drying and immersing in water. Flexural strength (FS) and elastic modulus (E) were determined by three bending tests using a universal test machine. Chlorhexidine release was monitored for 50 days. Streptococcus mutans UA159 was used in all microbiological assays. Inhibition halo assay was performed for 12 months and, also, biofilm growth for the specimens and colony-forming unit (CFU). Remineralization assay was used on restored teeth using measurements of microhardness Knoop and CFUs. Results: Conversion, sorption, and solubility were not affected by filler type and concentration. FS and E increase with the filler concentration, independent from filler type. Chlorhexidine was significantly released for 15 days for all experimental materials, and the increase in filler concentration decreased its release. Halo inhibition was observed for a longer time (12 months) in materials with 60 wt% filler at 70/30 proportion. Also, 60 wt% filler materials, independent from the filler ratio, reduced the CFU in relation to the control group from 8 to 12 months. In the remineralization assay, besides the absence of differences in hardness among the groups, after biofilm growth, the CFU was also significantly lower in materials with 60 wt% filler. Conclusions: Materials with 60% filler, preferentially with 70% barium glass and 30% silica, and 5% MMT/CHX particles demonstrated long-term antimicrobial activity, reaching 12 months of effectiveness. Also, this formulation was associated with higher mechanical properties and similar conversion, sorption, and solubility compared to the other materials. Full article

Predicting the mechanical performance of Engineered Cementitious Composite (ECC)-strengthened reinforced concrete (RC) beams is both meaningful and challenging. Although existing methods each have their advantages, traditional numerical simulations struggle to capture the complex micro-mechanical behavior of ECC, experimental approaches are costly, and data-driven methods heavily depend on large, high-quality datasets. This study proposes a novel physics-informed machine learning framework that integrates domain-specific empirical knowledge and physical laws into a neural network architecture to enhance predictive accuracy and interpretability. The approach leverages outputs from physics-based simulations and experimental insights as weak supervision and incorporates physically consistent loss terms into the training process to guide the model toward scientifically valid solutions, even for unlabeled or sparse data regimes. While the proposed physics-informed model yields slightly lower accuracy than purely data-driven models (mean squared errors of 0.101 VS. 0.091 on the test set), it demonstrates superior physical consistency and significantly better generalization. This trade-off ensures more robust and scientifically reliable predictions, especially under limited data conditions. The results indicate that the empirical-guided framework is a practical and reliable tool for evaluating the structural performance of ECC-strengthened RC beams, supporting their design, retrofitting, and safety assessment. Full article

Piezoelectric actuators, widely used in micro-positioning and active control systems, show important hysteresis characteristics. In particular, the hysteresis contribution is a complex phenomenon that is difficult to model when the input amplitude and frequency are time-dependent. Existing dynamic physical models poorly describe the hysteresis influence of industrial mechatronic devices. This paper proposes a novel hybrid data-driven model based on the Bouc–Wen and backlash hysteresis formulations to appraise and compensate for the nonlinear effects. Firstly, the performance of the piezoelectric actuator was simulated and then tested in a complete representative domain, and then using the committee machine approach. Experimental campaigns were conducted to develop an algorithm that incorporated Bouc–Wen and backlash hysteresis parameters derived via genetic algorithm (GA) and particle swarm optimization (PSO) approaches for identification. These parameters were combined in a committee machine using a set of frequency clusters. The results obtained demonstrated an error reduction of 23.54% for the committee machine approach compared with the complete approach. The root mean square error (RMSE) was 0.42 µm, and the maximum absolute error (MAE) appraisal was close to 0.86 µm in the 150–250 Hz domain via the Bouc–Wen sub-model tuned with the genetic algorithm (GA). Full article

Controlling dissolved nitrogen is critical to meeting increasingly stringent steel quality targets, yet the variable kinetics of gas absorption and removal across production stages complicate real-time decision-making. Leveraging a total of 291 metal samples, the research applied ordinary least squares (OLS) regression, enhanced by cointegration diagnostics, to develop four stage-specific models covering pig iron after desulfurization, crude steel in the basic oxygen furnace (BOF) before tapping, steel at the beginning and end of secondary metallurgy processing. Predictor selection combined thermodynamic reasoning and correlation analysis to produce prediction equations that passed heteroscedasticity, normality, autocorrelation, collinearity, and graphical residual distribution tests. The k-fold cross-validation method was also used to evaluate models’ performance. The models achieved an adequate accuracy of 77.23–83.46% for their respective stages. These findings demonstrate that statistically robust and physically interpretable regressions can capture the complex interplay between kinetics and the various processes that govern nitrogen pick-up and removal. All data are from U. S. Steel Košice, Slovakia; thus, the models capture specific setup, raw materials, and production practices. After adaptation within the knowledge transfer, implementing these models in process control systems could enable proactive parameter optimization and reduce laboratory delays, ultimately minimizing excessive nitrogenation in finished steel. Full article

High-Density Polyethylene (HDPE) plays a crucial role in the life of every human being due to its properties such as chemical resistance, light weight, and ease of forming, among others. Its usage ranges from bottles for beverages and other liquids, to pipes, wire and cable insulation, and prosthetics. As it undergoes several thermal cycles during its life cycle, it is essential to maintain its qualities, even after undergoing thermal and thermo-oxidative degradation. Here, various dosages of synthetic (Irganox 1010) and natural (vitamin E) antioxidants are added to HDPE formulations to study their impacts on HDPE stability. The antioxidants are mixed physically with HDPE before the mixtures are melt-mixed three times to represent their life cycles. Samples are taken after each time and used to analyze the molecular weight distribution, rheological behavior, mechanical properties, and thermal stability. The results show that vitamin E is superior to Irganox 1010 in these tests, as vitamin E performance exceeds that of Irganox 1010, even at lower doses. The only drawback of using vitamin E is the yellow color it causes, which may necessitate the addition of another additive to enhance the color stability of HDPE in color-sensitive applications. Full article

Objective: Anterior cruciate ligament (ACL) graft failure or contralateral ACL injury after returning to sport (RTS) post-ACL reconstruction remains problematic. Re-injury prevention programs that “bridge” standard physical therapy and release to unrestricted sports participation can help. This observational study evaluated the characteristics of athletes who sustained an ipsilateral ACL graft or contralateral ACL injury after RTS bridge program participation. Materials and Methods: Comparisons were made between RTS bridge program participants who either had or had not sustained an ipsilateral ACL graft or contralateral ACL injury following RTS. Post-program objective physical function tests, pre- and post-program Knee Outcome Survey Sports Activity Scale (KOS-SAS), global sports activities knee function scores, sports activities knee function rating improvements, and post-program sport performance ability perceptions were evaluated. Results: A total of 204 athletes (19.7 ± 6 years of age, 108 males) completed the RTS bridge program and were released back to sports at 8.5 ± 2.3 months post-surgery. Groups had similar pre-morbid performance level restoration perceptions. Taller and heavier male athletes displayed greater single leg triple hop for distance magnitude, and quicker single leg timed hop, single leg timed crossover hop, and NFL 5-10-5 and NFL “L” times. Bilateral physical function test symmetry results did not differ between groups. By 7.8 ± 4 years post-surgery, 17 subjects sustained either ipsilateral ACL graft injury (n = 6) or contralateral ACL injury (n = 11), with a similar frequency between males and females (p = 0.30). Athletes who sustained an ipsilateral ACL graft or contralateral ACL injury were younger, and more often scored ≥ 25th percentile for post-program global sports activities knee function and KOS-SAS scores; more frequently had two-level overall sports activities knee function rating improvements; and tended to sustain this new knee injury during the initial RTS season. Conclusions: Factors other than physical function or performance capability may possess a strong influence on ipsilateral ACL graft or contralateral ACL injury following RTS bridge program participation. Full article

Inside the transmission group of an agricultural tractor, the efficiency of power transfer to moving parts, their lubrication, and protection from wear are guaranteed by UTTO (Universal Tractor Transmission Oil) fluids, which are also used to operate the hydraulic system. These fluids, with mineral or synthetic origin, are characterized by excellent lubricating properties, high toxicity, and low biodegradability, which makes it important to replace them with more eco-sustainable fluids, such as those based on vegetable oils that are highly biodegradable and have low toxicity. It is also important to consider EU policies on the use of such fluids in sensitive environmental applications. To this end, several experimental bio-UTTO formulations were tested at CREA to evaluate—compared to conventional fluids—their suitability for use as lubricants for transmissions and hydraulic systems through endurance tests carried out in a Fluid Test Rig (FTR) specifically developed by CREA to apply controlled and repeatable work cycles to small volumes of oil, which are characterized by high thermal and mechanical stresses. The technical performance and the main physical–chemical parameters of the fluids were continuously monitored during the work cycles. Based on these experiences, this study describes the first application of a methodological approach aimed at testing an experimental biobased UTTO on a tractor used in normal farm activity. The method was based on a former test at the FTR in which the performance of the bio-UTTO was compared to that of the conventional UTTO recommended by the tractor manufacturer. Given the good results of the FTR test, bio-UTTO was introduced in a 20-year-old medium-power tractor, replacing the mineral fluid originally supplied, for the first reliability tests during its normal use on the CREA farm. After almost 600 h of work, the technical performance and the trend of chemical–physical parameters of bio-UTTO did not undergo significant changes. No damage to the tractor materials or oil leaks was observed. The test is still ongoing, but according to the results, in line with the indications provided by the FTR test, the experimental bio-UTTO seems suitable for replacing the conventional fluid in the tractor used in this study. Full article

This study systematically analyzes the influencing factors and optimization strategies of foam stability and performance for CO₂-soluble foaming agents in high-temperature and high-pressure (HTHP) complex reservoir environments. By constructing a HTHP experimental system and utilizing dynamic foam testing, interfacial tension analysis, and microscopic observation of liquid films, the effects of chemical factors (e.g., pH, foaming agent concentration, stabilizer synergy) and physical factors (e.g., temperature, pressure) on foam behavior are investigated. The results show that the nonionic surfactant E-1312 exhibits optimal foam performance in neutral to mildly alkaline environments. The foam performance tends to saturate at around 0.5% concentration. High pressure enhances the foam stability, whereas elevated temperature significantly reduces the foam lifetime. Moreover, the addition of nano-sized foam stabilizers such as silica (SiO₂) can significantly delay liquid film drainage and strengthen interfacial mechanical properties, thereby improving foam durability. This study further reveals the key mechanisms of CO₂-soluble foaming agents in terms of interfacial behavior, liquid film evolution, and foam formation in porous media, providing theoretical guidance and optimization pathways for the molecular design and field application of CO₂ foam flooding technology. Full article

Aluminium metal matrix composites (AMMCs) incorporate aluminium alloys reinforced with fibres (continuous/discontinuous), whiskers, or particulate. These materials were engineered as advanced solutions for demanding sectors including construction, aerospace, automotive, and marine. Micro- and nano-scale reinforcing particles typically enable attainment of exceptional combined properties, including reduced density with ultra-high strength, enhanced fatigue strength, superior creep resistance, high specific strength, and specific stiffness. Microstructural, mechanical, and tribological characterizations were performed, evaluating input parameters like reinforcement weight percentage, applied normal load, sliding speed, and sliding distance. Fabricated nanocomposites underwent tribometer testing to quantify abrasive and erosive wear behaviour. Multiple investigations employed the Taguchi technique with regression modelling. Analysis of variance (ANOVA) assessed the influence of varied test constraints. Applied load constituted the most significant factor affecting the physical/statistical attributes of nanocomposites. Sliding velocity critically governed the coefficient of friction (COF), becoming highly significant for minimizing COF and wear loss. In this review, the reinforcement homogeneity, fractural behaviour, and worn surface morphology of AMMCswere examined. Full article

Professor Hong Chaosheng, as the founding figure and pioneer of China’s hydrogen and helium cryogenic technology, played a pivotal role in advancing this field from its inception to global competitiveness. This paper systematically reviews the seven-decade-long cryogenic research trajectory of the Technical Institute of Physics and Chemistry, CAS (formerly the Cryogenic Technology Experimental Center), with particular emphasis on milestone scientific achievements and their significant applications. In the 1960s, the Institute’s breakthrough in long-piston-expander-precooled helium liquefaction technology provided critical support for China’s space technology and superconductivity research. Since the 21st century, building upon Professor Hong’s academic legacy, the Institute has successively overcome core technological challenges in developing high-speed helium turbine expanders, high-efficiency oil-flooded screw compressors, and superfluid helium temperature refrigeration systems. These innovations have yielded a complete series of large-scale cryogenic equipment with independent intellectual property rights. These advancements have been successfully applied in national megaprojects such as neutron sources and superconducting magnet testing facilities, with some technical parameters reaching internationally leading standards. Looking ahead, with the rapid development of quantum computing and fusion energy, China’s hydrogen–helium cryogenic technology will continue to optimize equipment performance while expanding application frontiers through enhanced international collaboration, thereby making greater contributions to cutting-edge scientific research and clean energy development. Full article

Water plays a fundamental role in sustaining biological processes, ecological functions, and economic systems. However, the progressive pollution of water sources compromises these functions, posing significant threats to water purity, human well-being, and environmental sustainability. Human activities, such as industrial waste, agriculture, and urbanization, alongside natural processes, are major contributors to the deterioration of surface water quality, which in turn leads to environmental and economic risks. The decline in water quality results in issues such as waterborne diseases, loss of biodiversity, and a shortage of clean water for consumption and industrial use. This paper emphasizes the critical need for maintaining good water quality and the importance of implementing effective strategies for the removal of physical, chemical, and biological contaminants. In response, this work presents an intelligent embedded system (electronic control unit, ECU) developed as part of a modular filtration system designed to improve surface water quality, provide more precise water analyses, and perform tests within a controlled environment. Full article

This study investigated associations between substitutions and match running performance (MRP) under the new five-substitution rule, utilising running data from the 2022 FIFA World Cup involving all 32 participating men’s national teams, comprising elite professional football players at the highest international competitive level. A paired sample t-test compared running performance among entire match players (EMP), replaced players (RP), and substitute players (SP) per team per match. A linear mixed model (LMM) was used to analyse the association between substitutions and MRP while also considering match-related factors associated with MRP as covariates and controlling for team variations. The main finding was that substitute players exhibit superior running performance compared to RP and EMP. Running metrics related to match outcomes indicate that more substitutions are associated with increases in total running distance and the number of sprints. This study highlights the importance of substitutions on team running performance under the new rules in modern elite football. Coaches can optimise their substitution strategies and physical training according to the new rules to meet the high-intensity demands of the game. Full article

Background/Objectives: There is growing interest in non-diet approaches to support health, well-being, and performance in different populations. The aim of this study was to evaluate the effects of a 12-week intuitive eating (IE) intervention on participants’ body composition, body image, eating behaviors, and athletic performance. Methods: The study included both an intervention group and a control group. It was conducted between September and December 2021. Participants were recruited from a sports center in Istanbul, where they had applied for nutrition and exercise counseling. Inclusion criteria included being 18–65 years old, not having engaged in regular physical activity in the past month, having no chronic disease, and not using any regular medications. Participants were not randomly assigned to groups; allocation was based on availability and willingness to attend the intervention sessions. The study involved 57 participants who were healthy adults between 18 and 65 years old and followed a structured exercise program. At the beginning of the study, a demographic questionnaire was administered. The anthropometric measurements were taken at the beginning and at the end of the intervention. In addition, validated performance and psychometric assessment tools were used, including the Cooper test for cardiovascular endurance, the Davies test for upper-body agility, and the 1-RM bench press for muscular strength, alongside standardized self-report questionnaires for eating attitudes (EAT-26), IE (IES-2), and body image (BCS). Results: The intervention group did not show any statistically significant changes in body composition (p > 0.05). The post-intervention means of the intervention and control groups were not statistically different (p > 0.05). The intervention group showed significant improvements in cardiovascular endurance, agility, and strength performance scores compared to the control group after the intervention (p < 0.05). The intervention group showed significant improvements in body image scores (p < 0.05) and eating attitude scores (p < 0.05). The post-intervention eating attitude and body image scores of the intervention group were significantly different from those of the control group (p < 0.05). The results of the correlation analysis showed a significant positive correlation between intuitive eating and body image (r = 0.455; p < 0.05) and a significant negative correlation between IE and disordered eating attitudes (r = −0.449; p < 0.05). Conclusions: These findings suggest that longer-term interventions may be beneficial and warrant further investigation. IE may serve as a promising strategy to enhance psychological well-being and performance outcomes without focusing on weight control. Full article