Search Results (1,362)

Understanding the long-term dynamics of cropland water use efficiency (WUE) and its underlying environmental drivers is essential for ensuring food and water security, particularly for regions facing intensified climate change. Here, we investigated the spatial patterns and long-term trends of gross primary productivity (GPP), evapotranspiration (ET), and WUE in cropland ecosystems across Northeast China during the past two decades as the nation’s primary commodity grain base using the time-series Breathing Earth System Simulator (BESS) products. Subsequently, the ridge regression method was used to quantitatively disentangle the relative contributions of key climatic variables to the observed WUE trends of cropland. Our results revealed a pronounced decreasing gradient in both GPP and ET along the southeast–northwest direction. A significant increase in GPP was observed over the 20-year period (p < 0.01), with 95.94% of the cropland area showing positive trends. ET showed a slight, non-significant increase (p > 0.05), though 82.77% of pixels exhibited positive trends, particularly in the northwest. Consequently, WUE showed a widespread and significant enhancement (p < 0.01), with approximately 98% of cropland pixels exhibiting increasing trends. Attribution analysis identified air temperature as the dominant environmental variable, accounting for 92.4% of the observed WUE increase, while solar radiation and precipitation contributed modestly (3.4% and 3.2%, respectively). Our findings underscore the predominant role of thermal conditions in shaping the carbon–water coupling efficiency of agroecosystems in semi-arid to semi-humid transition zones. This study provides quantitative evidence that warming climate, rather than changes in water availability or radiation, has been the primary climatic factor driving the improved cropland WUE over the past two decades. These insights have important implications for developing adaptive water management strategies to enhance agricultural climate resilience in Northeast China and similar regions worldwide. Full article

Accurate assessment of mitral valve (MV) and pulmonary vein (PV) flow velocities is important for left ventricular diastolic function testing. This study investigated the scan–rescan reproducibility of 4D Flow MRI-assessed MV and PV flow velocities in 21 healthy volunteers (25 ± 4 years). Participants underwent repeated whole-heart 3T 4D Flow MRI involving repositioning and different respiratory compensation strategies (motion-uncompensated free-breathing vs. respiratory motion-compensated navigator gating). MV parameters (net flow volume (NFV), E-wave velocity, A-wave velocity, E/A ratio, E deceleration time (DT), annular e’ velocity, E/e’ ratio) and PV parameters (NFV, S-wave velocity, D-wave velocity, S/D ratio, atrial reversal (AR) wave velocity) were derived from velocity–time curves and compared using intraclass correlation coefficients (ICCs), Bland–Altman analysis, and Pearson’s correlation (r). Results showed significant moderate-to-strong scan–rescan agreement and correlation for most MV and PV parameters (ICC = 0.51–0.92; r = 0.51–0.92; all p < 0.05), except E DT, e’ velocity, E/e’ ratio, PV NFV, and AR velocity (ICC = −0.13–0.47; r = −0.14–0.47). Subanalysis of respiratory motion strategies showed moderate-to-strong agreement and correlation for MV and PV parameters (ICC = 0.61–0.99; r = 0.52–0.99; all p < 0.05 excluding E DT), except E DT (ICC = 0.44) and PV NFV (ICC = 0.46; r = 0.46). While intraobserver agreement was mostly moderate-to-excellent (ICC = 0.58–0.97; ICC = 0.41 for E DT), interobserver agreement was poor for E DT and PV parameters (ICC = −0.12–0.34). Overall, 4D Flow MRI shows acceptable reproducibility for selected diastolic flow parameters, particularly mitral inflow indices, but substantial variability and limited robustness for key indices currently restrict its clinical applicability. Full article

Wind turbine blades are subjected to complex environmental conditions during long-term operation, which may lead to structural degradation and performance loss. To ensure structural integrity, fatigue testing prior to deployment is essential. This paper proposes a vision-based method for measuring the full-cycle breathing deformation of wind turbine blades during fatigue testing. The method captures dynamic image sequences of the blade’s hotspot cross-section using industrial cameras and employs a feature-based template matching approach to reconstruct the three-dimensional coordinates of target points. Through coordinate transformation, the deformation trajectories are obtained, enabling quantitative analysis of the blade’s dynamic responses in both flapwise and edgewise directions. A dedicated hardware–software system was developed and validated through full-scale fatigue experiments. Quantitative comparison with strain gage measurements shows that the proposed method achieves mean absolute deviations of 0.84 mm and 0.93 mm in two independent experiments, respectively, with closely matched deformation trends under typical loading conditions. These results demonstrate that the proposed method can reliably capture the global deformation behavior of the blade with millimeter-level accuracy, while significantly reducing instrumentation complexity compared to conventional contact-based approaches. The proposed method provides an effective and practical solution for full-field dynamic deformation measurement in blade fatigue testing, offering strong potential for structural health monitoring and early damage detection in wind turbine systems. Full article

Large-section tunnels produce a large amount of dust after drill-and-blast construction. If not removed in a timely manner, the dust will seriously endanger workers’ health. For the purpose of enhancing the working conditions within the tunnel during construction, this investigation employs an integrated methodology that combines computational simulations with on-site measurements. Drawing upon the principles of gas–solid two-phase flow theory, the coupled diffusion law of airflow and dust in large-section tunnels is investigated. A two-factor orthogonal experiment combined with economic analysis is employed to determine the optimal ventilation parameters for the forced ventilation system. The findings indicate that, when the initial ventilation configuration is applied, the airflow field is divided into three stages, and dust diffusion is primarily driven by airflow. The average dust concentration in the 1.6 m breathing zone at 600 s post-blasting is measured to be 36.8 mg/m³. While satisfying the ventilation demand stipulated for the tunnel, the optimal ventilation parameters are determined as an outlet air velocity of 18 m/s and a duct-to-face distance of 40 m. Under these conditions, the dust concentration is reduced to 1.5 mg/m³, representing a 95.9% improvement in dust removal efficiency. Additionally, the hourly electricity cost at 18 m/s is USD 4.39 lower than that at 20 m/s. This study provides valuable insights for optimizing forced ventilation parameters in large-section tunnels, significantly reducing pollutant levels while saving costs. Full article

Designing high-speed wide-angle optics for large-format mirrorless cameras presents a fundamental engineering conflict between the short flange back distance and the requirement for high-resolution aberration correction. To address this challenge, this study proposes a compact 18.5 mm F/2.0 lens system utilizing a modified retrofocus architecture equipped with an internal floating-focus mechanism. The design methodology integrates glass-molded aspherical surfaces to suppress high-order aberrations and employs passive athermalization strategies to maintain stability across a temperature range of −30 °C to +70 °C. Performance was rigorously evaluated using numerical simulations in Zemax OpticStudio, alongside comprehensive Monte Carlo tolerance analysis. Simulation results demonstrate exceptional optical performance, with the Modulation Transfer Function (MTF) exceeding 0.5 at a spatial frequency of 100 lp/mm across the field. Furthermore, focus breathing is restricted to less than 1%, and optical distortion is strictly controlled within 2%. The Monte Carlo tolerance analysis predicts a manufacturing yield exceeding 80% under standard industrial precision levels. Ultimately, this work provides a theoretically sound, athermally stable, and highly manufacturable solution suitable for next-generation high-resolution mirrorless sensors. Full article

Background: Chronic Obstructive Pulmonary Disease (COPD) remains a leading cause of emergency department (ED) presentation, hospitalisation, and preventable healthcare utilisation worldwide. Although guidelines advocate coordinated, preventative, and community-based management, care within ED settings often remains reactive and crisis-driven. Nurses occupy a central role in COPD management; however, the experiential dimensions of nursing practice and its contribution to improving patient outcomes are insufficiently understood. Objectives: To explore the lived experiences of patients, nurses and medical officers regarding COPD presentations to the ED, with particular focus on the nursing role in assessment, coordination, education, and identification of unmet and comorbid care needs. Methods: A qualitative phenomenological approach was undertaken across three regional Australian EDs. Purposive sampling recruited patients presenting with acute exacerbations of COPD and nursing and medical officers involved in their care. Semi-structured interviews were conducted and transcribed verbatim. Data were analysed using Braun and Clarke’s thematic analysis framework, supported by reflexive discussion and audit trails to enhance rigour. Results: Six interrelated themes were identified: (1) nursing within a “crisis first” model of care; (2) holistic assessment and translation of complexity; (3) education and care coordination as preventative nursing work; (4) relational care and therapeutic connection; (5) nurses as sentinels for undiagnosed comorbidities, particularly obstructive sleep apnoea; and (6) system pressures constraining optimal nursing practice. Participants consistently described nurses as the clinicians who stabilised acute episodes, interpreted contextual risks, coordinated services, and provided relational and educational support, yet whose preventative contributions were limited by time and organisational demands. Conclusions: ED nurses function as critical integrators between acute stabilisation and chronic disease management for patients with COPD. Formalising nurse-led assessment, education, coordination, and sleep-disordered breathing screening may reduce avoidable ED presentations and enhance patient-centred outcomes. Investment in structured nursing models represents a key opportunity for improving COPD care delivery. Full article

Chronic obstructive and inflammatory lung diseases share overlapping clinical manifestations and spirometric features, complicating differential diagnosis and monitoring. In this study, we performed an integrative real-time proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS) breathomics analysis to assess whether exhaled volatile organic compound (VOC) profiles enable multiclass discrimination among bronchial asthma (BA), chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), and lymphangioleiomyomatosis (LAM), with healthy individuals as controls. Breath VOC data from 843 subjects were analyzed using a stratified 70/30 train/test split. An ensemble feature selection strategy based on gradient boosting (XGBoost with SMOTE within cross-validation) identified stable VOC panels (top 25% selection probability), yielding 29 VOCs and 31 features including clinical covariates. On the independent test set, the VOC-only model achieved a macro-averaged one-vs-one (OvO) AUC of 0.866 (95% CI 0.829–0.903), while the combined model improved to 0.888 (95% CI 0.853–0.919), indicating modest value of clinical variables. Pairwise analysis demonstrated highest discrimination for CF (AUC up to 0.988), whereas BA and LAM showed lower sensitivity (<0.60), likely reflecting heterogeneity and limited sample size. Given differences in age, sex, BMI, and smoking status across cohorts, confounding effects were assessed, confirming that VOC signatures retain independent diagnostic information. Disease-specific VOC interaction networks revealed distinct remodeling patterns, with central metabolites not captured by univariate analysis. Overall, PTR-TOF-MS breathomics demonstrates proof-of-concept multiclass discrimination across chronic lung diseases. Full article

Background: Obstructive sleep apnea (OSA) is a common but underrecognized sleep-related breathing disorder characterized by intermittent hypoxemia and autonomic dysfunction. OSA prevalence and clinical relevance in Type 1 Diabetes Mellitus (T1DM), particularly in relation to diabetes-related vascular complications, remain insufficiently explored. Objective: The aim of this study was to evaluate the prevalence of high-risk OSA in adults with T1DM and controls, and to investigate the association between high-risk OSA and microvascular complications among individuals with T1DM. Methods: In this cross-sectional case–control study, 102 adults with T1DM and 126 controls were included. OSA risk was assessed using the modified Berlin Questionnaire (mBQ). Analyses of vascular complications were restricted to participants with T1DM. Multivariable logistic regression models adjusted for age and sex were used to assess associations, with additional adjustments for body mass index, hypertension, current smoking, alcohol use and glycated hemoglobin A1c. Results: High-risk OSA was identified in 18.6% of individuals with T1DM and 11.9% of controls, with no significant difference between groups. Among participants with T1DM, the prevalence of microvascular complications (retinopathy and/or neuropathy) was substantially higher in those with high-risk OSA compared with those at low risk (68.4% vs. 18.07%, p <0.001). In univariate logistic regression analysis, high-risk OSA was significantly associated with microvascular complications (odds ratio [OR] 4.85; 95% confidence interval [CI] 1.65–14.24; p = 0.004). This association remained significant in the fully adjusted model (OR 5.55; 95% CI 1.36–22.65; p = 0.017). Conclusions: High-risk OSA is not more prevalent in adults with T1DM compared with controls; however, among individuals with T1DM, high-risk OSA is strongly and independently associated with microvascular complications. Given the potential contribution of diabetic microvascular and autonomic neuropathy to upper airway dysfunction, the relationship between OSA and vascular complications in T1DM may be bidirectional, warranting further longitudinal investigation. Full article

Background: Obstructive sleep apnoea (OSA) is a highly prevalent yet underdiagnosed disorder in patients with cardiovascular disease. Growing evidence suggests a pathophysiological link between OSA and coronary artery disease (CAD); however, the relationship between OSA severity and anatomical complexity of coronary lesions remains incompletely understood. Aim: The aim of this study is to assess the prevalence of OSA in patients undergoing coronary angiography and to evaluate the association between sleep-disordered breathing parameters and the severity of CAD expressed by the SYNTAX score. Methods: This prospective study enrolled 103 consecutive patients referred for invasive coronary angiography. All participants underwent overnight type III cardiorespiratory polygraphy. OSA severity was classified according to the Apnea–Hypopnea Index (AHI). The anatomical complexity of CAD was assessed using the SYNTAX score. Linear regression analyses were performed to determine associations between polysomnographic parameters and SYNTAX score. Results: Significant CAD was diagnosed in 74.8% of patients. OSA was highly prevalent, with severe OSA observed in 36.4% of patients with significant CAD compared to 3.8% in those without significant stenoses (p = 0.003). Patients with significant CAD had higher AHI (18.8 vs. 13.5 events/h; p = 0.003), higher oxygen desaturation index (ODI) (19.3 vs. 12.9 events/h; p = 0.003), and greater mean oxygen desaturation (4.1% vs. 3.8%; p = 0.008). In multivariable regression analysis, AHI (B = 0.329; 95% CI [0.083, 0.576]; p = 0.009) and nicotinism (B = 8.693; 95% CI [2.573, 14.814]; p = 0.006) independently predicted higher SYNTAX scores. Interestingly, each 1% increase in snoring percentage was associated with a 0.203-point reduction in SYNTAX score (95% CI [−0.339, −0.068]; p = 0.004). Conclusions: OSA is highly prevalent in patients undergoing coronary angiography and is independently associated with greater anatomical complexity of CAD. Sleep-disordered breathing, particularly AHI and nocturnal hypoxemia, may represent important non-traditional risk markers of advanced coronary atherosclerosis. Systematic screening for OSA should be considered in patients with suspected or confirmed CAD. Full article

Background: Metabolic syndrome is associated with early impairments in cellular bioenergetics that are not fully captured by conventional body composition measures. Molecular hydrogen, produced endogenously through gut microbial fermentation and measurable in breath, has been implicated in redox and mitochondrial regulation. Whether breath hydrogen relates to preservation of intracellular, metabolically active tissue in metabolic syndrome remains unclear. Objectives: To examine the association between breath hydrogen concentration and an integrated cellular bioenergetic phenotype derived from intracellular body composition indices in sedentary adults with metabolic syndrome. Methods: Twenty-eight sedentary, middle-aged adults (51.2 ± 7.9 years, 19 females) with metabolic syndrome underwent fasting breath hydrogen assessment and multifrequency bioelectrical impedance analysis. A composite cellular bioenergetic phenotype was derived using principal component analysis of body cell mass, intracellular water, total body potassium, and glycogen. Associations between breath hydrogen and the composite phenotype were evaluated using Spearman correlation with bootstrapped confidence intervals, Theil-Sen regression, and Bayesian linear regression adjusted for age, sex, and waist circumference. Sensitivity analyses included fat-free mass. Results: A single principal component explained 98.6% of the variance across intracellular variables, indicating a highly coherent cellular bioenergetic phenotype. Breath hydrogen concentration was positively associated with this phenotype (ρ = 0.43, p = 0.021; BCa 95% CI 0.07–0.70). Theil-Sen regression confirmed a robust positive association (β = 0.017 per ppm hydrogen; 95% CI 0.002–0.046). Bayesian models showed posterior distributions centered on positive effect sizes, independent of central adiposity. In contrast, the association with fat-free mass alone was borderline. Conclusions: Breath hydrogen concentration reflects an integrated intracellular bioenergetic phenotype in sedentary adults with metabolic syndrome, tracking cellular quality rather than lean mass quantity. Breath hydrogen may serve as a non-invasive biomarker of cellular bioenergetic integrity and a potential tool for phenotype-guided metabolic interventions. Full article

MOS gas sensors have proven to be useful in electronic noses, which utilize these sensors to detect volatile organic compounds in human breath to detect various lung diseases. Unfortunately, the long settling time of MOS gas sensors is ill-suited to measuring human breath, where complete breathing cycles are often shorter than 5 s. Existing studies circumvent this limitation by collecting gas samples and injecting them into a sealed chamber to react with the sensors. However, it would be convenient if breath-by-breath analysis could be conducted without the need to store breath samples. To accomplish this, we present a novel forecasting methodology to predict the final value $t_{\infty }$ of a gas sensor’s response based on its initial transient behavior. To do this, we present and validate a second-order mathematical model of the sensors’ response characteristics, which we then use in our preliminary work using neural networks to predict the final sensor value. Although some challenges were encountered, the initial results are encouraging, and we plan to extend our study in the future to collect a more expansive dataset and explore the use of other types of machine learning algorithms for this application. Full article

Introduction: The role of medical simulation technicians varies across countries and institutions. Technicians ensure simulators function according to the designed training scenarios and manage their physiological responses, such as breathing and circulation. They are responsible for ongoing maintenance, repairs, and software installation or updates. Additionally, they manage audio–video systems, including recording simulation sessions, organizing live broadcasts, and preparing materials for post-training review and analysis. These responsibilities suggest that technicians contribute to the technical and organizational foundations of simulation-based education. Methods: This exploratory study used a predominantly quantitative survey design with an additional qualitative component. An open-ended question allowed respondents to freely express their opinions and reflections regarding the professional responsibilities of medical simulation technicians. This mixed-methods approach enabled both statistical analysis and deeper insight into the technicians’ perspectives. Results: Thirty-five simulation technicians participated in the study. Most respondents were men (71.43%), while women accounted for 28.57%. Respondents reported performing a broad range of technical, organizational, and selected educational support tasks. Conclusions: This exploratory study suggests that medical simulation technicians in Poland perform a broad range of technical, organizational, and selected educational support tasks. The findings also indicate local variability in role configuration and unclear boundaries between technical and educational responsibilities. Given the limited sample size and purposive recruitment strategy, the results should be interpreted cautiously. Full article

Background/Objectives: Determining the optimal timing for the discontinuation of mechanical ventilation (MV) in pediatric patients following cardiac surgery remains challenging. Both delayed and premature extubation increase the risk of complications. The rapid shallow breathing index (RSBI) is widely used, but its role and optimal cutoff in pediatric cardiac populations remain uncertain. This study aimed to determine a clinically useful RSBI cutoff for predicting extubation readiness in children after cardiac surgery. Methods: We conducted a prospective single-center observational cohort study including children younger than 18 years who required postoperative MV after cardiac surgery and were admitted to the Pediatric Intensive Care Unit (PICU) between July 2020 and June 2024. The RSBI was measured one minute prior to extubation during a spontaneous breathing trial (SBT). Extubation failure was defined as the need for reintubation within 48 h. Results: A total of 247 patients were enrolled, with 13 (5.3%) experiencing extubation failure. Patients who failed extubation had significantly higher RSBI values compared with those successfully extubated (median 4.97 vs. 3.76; p < 0.001). An RSBI cutoff ≥ 4.62 breaths/min/mL/kg provided a sensitivity of 84.6%, specificity of 94.0%, positive predictive value (PPV) of 44%, and negative predictive value (NPV) of 99.1%. The RSBI was the only independent predictor of extubation failure in multivariable analysis (p = 0.014). Conclusions: The RSBI is a simple and reliable physiological marker for assessing extubation readiness in pediatric patients after cardiac surgery. An RSBI threshold of ≥4.62 breaths/min/mL/kg identifies patients at increased risk of extubation failure. Larger, multicenter studies will be important to validate our results. Full article

(1) Background: Early treatment of sleep-disordered breathing (SDB) with adaptive servo-ventilation (ASV) after acute myocardial infarction (AMI) has been shown to improve myocardial salvage. This analysis evaluates nocturnal electrocardiogram (ECG) Holter data, derived from polygraphy in a randomised clinical trial (NCT02093377), to assess the occurrence of nocturnal cardiac arrhythmias in patients with SDB and to explore the effect of ASV therapy. (2) Methods: In the TEAM-ASV I trial, patients were stratified by the presence/absence of SDB, defined by an apnoea–hypopnoea index (AHI) ≥15 events/h assessed with polygraphy. Those with SDB were subsequently randomised to receive ASV in addition to standard AMI care. Guideline-conforming semi-automated ECG analysis of nocturnal cardiac arrhythmias was conducted via Holter–ECG software (custo diagnostic, version 5.4). (3) Results: Patients with SDB had an increased incidence of non-sustained ventricular tachycardia (NSVT) (SDB: n = 8 (16%) vs. no SDB: n = 1 (2%); p = 0.024) and premature atrial contractions (PAC) (SDB: 1.2/h [0.3, 3.4] vs. no SDB: 0.3/h [0.1, 1.2]; p = 0.017). In patients with SDB who were randomised to ASV treatment early after AMI, we found no reduction in cardiac arrhythmias when ASV was added to standard care. (4) Conclusions: After AMI, SDB was linked to increased NSVT and PAC. ASV treatment demonstrated neither a harmful nor a beneficial effect on the occurrence of nocturnal cardiac arrhythmias. Further trials are warranted to confirm these findings. Full article

Preterm birth interrupts critical phases of lung development and is associated with long-term alterations in respiratory structure and function. While bronchopulmonary dysplasia (BPD) has traditionally been considered the principal determinant of adverse outcomes, accumulating evidence indicates that prematurity per se contributes substantially to persistent pulmonary impairment. Lung function trajectories in preterm-born children frequently track along lower percentiles from infancy into adolescence and early adulthood, with limited catch-up growth and increased vulnerability to chronic airflow limitation. Assessment of lung function requires a developmentally tailored approach, as feasibility and interpretability vary across age groups. In infancy, non-volitional techniques such as tidal breathing flow-volume loop analysis and raised-volume rapid thoracoabdominal compression allow early evaluation of respiratory mechanics. During toddlerhood, methodological limitations persist, although emerging technologies may expand feasibility. In preschool children, impulse oscillometry enables detection of small airway dysfunction, often preceding spirometric abnormalities. From school age onward, spirometry, body plethysmography, diffusing capacity, and multiple breath washout provide complementary information on obstructive, restrictive, and gas-exchange impairments. Longitudinal studies demonstrate that reduced lung function is not confined to children with BPD and may predispose to early-onset chronic obstructive pulmonary disease-like phenotypes. Early identification of abnormal trajectories and modifiable risk factors supports structured long-term follow-up and preventive strategies. Standardization of age-specific assessment protocols and harmonization of reference values are essential to improve risk stratification and optimize long-term respiratory outcomes in this vulnerable population. Full article