Search Results (1,248)

Maintaining optimal humidity in livestock buildings during winter is a major challenge in cold climate regions due to the conflict between moisture-removing ventilation and the need for heat preservation. To address this issue, a novel condensation dehumidification system is proposed that utilizes the natural low temperature of cold winters. An integrated energy consumption model, coupling moisture and thermal balances, was developed to evaluate room temperature drop, dehumidification rate (DR), and the internal circulation coefficient of performance (IC-COP). The model was calibrated and validated with experimental data comprising over 150 operational cycles under varied operation conditions, including initial temperature differences (ranging from −20 to −5 °C), air flow rates (0.6–1.5 m/s), refrigerant flow rates (3–7 L/min), and high-humidity conditions (>90% RH). Correlation analysis showed that higher indoor humidity improved both DR and IC-COP. Four machine learning models—Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), Random Forest (RF), and Multilayer Perceptron (MLP)—were developed and compared with a stacking ensemble learning model. Results demonstrated that the stacking model achieved superior prediction accuracy, with the best R² reaching 0.908, significantly outperforming individual models. This work provides an energy-saving dehumidification solution for enclosed livestock housing and a case study on the application of machine learning for energy performance prediction and optimization in agricultural environmental control. Full article

Objective—Partial do-not-resuscitate (DNR) orders, directives specifying limited resuscitative efforts, are intended to align medical interventions with patient preferences. However, their complexity may introduce ambiguity, inconsistent care, and ethical challenges. Design—A retrospective review was conducted of inpatient partial code order entries over a three-year period at a single institution with a pediatric oncology and immunology cohort. Partial DNR orders were identified and categorized based on included or excluded interventions (chest compressions, defibrillation, intubation, mechanical ventilation, medications). Data was analyzed to assess the frequency, variation, and internal consistency of documented preferences as well as alignment with institutional definitions and clinical feasibility. Results—Partial DNR orders represented a small (n = 15, 7%) but notable proportion of total code status entries. Wide variability was observed in the combinations of permitted and withheld interventions, with orders containing internally conflicting instructions. Documentation of inconsistencies and unclear terminology were common, raising concerns about interpretability during emergent situations. Conclusions—Partial DNR orders demonstrate heterogeneity and potential for miscommunication. These findings suggest that while partial codes may reflect nuanced patient preferences, they pose operational and ethical risks that could compromise care clarity. Clinical implications are reviewed. These findings will guide institutional deliberations regarding whether to refine, restrict, or eliminate partial code order options to enhance patient safety and decision-making transparency. Full article

This paper presents the concepts of a vehicle pressure regulation ventilation system based on the results of absolute pressure measurements in land transport vehicles: passenger cars, buses and trains. Despite the fact that absolute pressure affects human well-being and health, this parameter is often overlooked in studies assessing thermal comfort. Absolute pressure measurements were taken during normal passenger transport operation. The studies were conducted for various terrain types: lowlands, highlands, and mountains. Absolute pressure fluctuations in land transport depended primarily on altitude, with the largest atmospheric pressure differences recorded in mountains and the smallest in lowlands. A pressure change of 8 hPa within a 24 h period constitutes an unfavorable mechanical stimulus for the human body and causes changes in the excitability of the nervous system. In all measurement series, absolute pressure fluctuations exceeded 8 hPa. Based on the results of absolute pressure measurements and altitude, a simplified model for predicting absolute pressure in transport vehicles was developed. To reduce absolute pressure fluctuations inside passenger land vehicle cabins, a ventilation scheme regulating pressure inside land vehicle cabins was proposed. Full article

Background/Objectives: Pediatric trauma systems require accurate metrics for evaluating triage decisions. Undertriage occurs when an injured child requires pediatric trauma center resources but is treated at a center lacking those resources. Current undertriage definitions utilize mortality-based scores, including the Injury Severity Score (ISS) > 15 or the International Classification of Disease (ICD) Injury Severity Score (ICISS) > 10. However, resource-based metrics like the ICD Critical Care Severity Score (ICASS) may be preferable in children. This study evaluated the relationship of ISS, ICISS and ICASS to the need for pediatric trauma resources (NFPTCR) to derive a more empiric definition of undertriage. Methods: The American College of Surgeons Trauma Quality Improvement Program database was queried for patients aged ≤ 15 years old. NFPTCR was defined as blood product transfusion within 4 h, invasive procedure for cardiopulmonary stabilization/contamination/bleeding within 72 h, initial admission to intensive care unit (ICU) or ICU stay ≥ 3 days, intubation, mechanical ventilation and general anesthesia ≤ 5 years old, or physical child abuse. ICASS and ICISS were derived from 2014 to 2018 datasets and applied to the 2019 dataset. The ability of ISS, ICISS and ICASS to distinguish NFPTCR patients was assessed using multivariable logistic regression and receiver–operator characteristic (ROC) analysis. Results: Out of 97,773 children, 15,985 (16%) were NFPTCR+. ISS, ICISS and ICASS had areas under the curve of 0.760, 0.701 and 0.812 for NFPTCR+, respectively (all p < 0.001). ISS had 36% sensitivity at 15; whereas ICASS had 95%, 93% and 89% sensitivity at 5, 10 and 15, respectively. Conclusions: ICASS was superior to ISS and ICISS for identifying NFPTCR. Consideration should be given to redefining pediatric trauma undertriage based on resource-based metrics, like ICASS. Full article

Background and Objectives: Healthcare-associated infections (HAIs) significantly increase morbidity and mortality in critically ill patients, and their burden became more pronounced during the COVID-19 pandemic. However, data describing the temporal evolution of HAIs, pathogen distribution, and associated risk factors across consecutive pandemic waves remain limited. This study aimed to characterize the epidemiology, microbiology, and outcomes of HAIs in COVID-19 intensive care units (ICU) patients and to identify clinical and laboratory predictors of mortality. Materials and Methods: This retrospective observational study included adult patients with RT-PCR–confirmed COVID-19 who developed at least one HAI ≥ 48 h after ICU admission between March 2020 and December 2020, encompassing the first three pandemic waves in Türkiye, in a tertiary-care ICU. Demographic, clinical, laboratory, and microbiological data were collected. Inflammatory markers and severity scores (SAPS-II, MCCI, and NLR) were analyzed. Receiver operating characteristic (ROC) curve analysis was used to determine optimal cut-off values for mortality prediction. Results: Among the 1656 ICU admissions, 145 patients (8.7%) developed HAIs; after exclusions, 136 patients were included in the final analysis. Bloodstream infections were the most frequent HAI (57%), followed by urinary tract infections (31%), ventilator-associated pneumonia (9%), and surgical site infections (1%). Klebsiella pneumoniae was the predominant pathogen, followed by Candida albicans and Acinetobacter baumannii. Multidrug-resistant organisms, including MRSA and VRE, showed variable distribution across pandemic periods. Overall in-hospital mortality was 74.3%. Non-survivors had significantly higher SAPS-II, MCCI, and NLR values. ROC analysis identified NLR > 38.8 and SAPS-II > 35.5 as mortality-predictive thresholds. Dynamic inflammatory marker patterns correlated with infection timing, and early peaks of CRP, WBC, and IL-6 were associated with worse outcomes. Conclusions: HAIs imposed a substantial clinical burden on critically ill COVID-19 patients, with high mortality driven predominantly by multidrug-resistant bloodstream infections. Severity indices and inflammation-based biomarkers demonstrated strong prognostic value. Temporal shifts in pathogen ecology across pandemic waves underscore the need for adaptive infection-prevention strategies, continuous microbiological surveillance, and strengthened antimicrobial stewardship in critical care settings. Full article

Traditional cardiopulmonary resuscitation (CPR) training faces limitations such as instructor dependency, low efficiency, and subjective assessment. To address these issues, this study proposes a novel computer vision-based method for the automation and objective evaluation of artificial respiration, shifting focus to the long-overlooked ventilation component. We developed an evaluation framework integrating human pose estimation and spatio-temporal graph convolution network (ST-GCN): first, OpenPose is utilized to extract skeletal keypoints of the rescuer, followed by action classification and recognition-including chest compressions, airway opening, and artificial breathing via a ST-GCN. Based on the American Heart Association (AHA) guidelines, this research defines and implements five quantitative metrics for ventilation quality, including CPR operation procedure, chin-frontal angle, interruption time, ventilation time, and ventilation frequency. An automated scoring model was established accordingly. Validated on a self-constructed dataset containing multi-source videos, the model achieved an accuracy of 87.64% in recognizing artificial respiration actions and 84.47% in evaluating action standardization. Experimental results demonstrate that the system can effectively and objectively evaluate the quality of artificial respiration. Compared with traditional instructor-dependent approaches, this study provides a low-cost, scalable technical solution, offering a new pathway for promoting high-quality CPR training. Full article

Background/Objectives: Minimally invasive coronary artery bypass grafting (MICS-CABG) offers reduced access trauma compared with conventional off-pump coronary artery bypass (OPCAB) but requires more demanding surgical and anesthetic conditions, including single-lung ventilation. Enhanced Recovery After Cardiac Surgery (ERACS) pathways—particularly those incorporating early extubation in a post-anesthesia care unit (PACU) and routine ICU bypass—may harmonize postoperative recovery across different surgical approaches. This study evaluated whether a standardized early-extubation ERACS protocol could achieve comparable short-term recovery outcomes between MICS-CABG and OPCAB. Methods: This single-center retrospective study included all adult patients who underwent off-pump MICS-CABG via mini-thoracotomy or OPCAB via sternotomy between January 2020 and December 2024 within an ERACS pathway. Propensity score matching (1:1) was applied using key demographic and clinical variables. Primary outcomes were hospital length of stay (LOS), ventilation time, and unplanned ICU transfer. Secondary outcomes included postoperative complications, transfusion requirements, pain scores, and in-hospital mortality. Results: Of 144 MICS-CABG patients, 131 met inclusion criteria and 116 were propensity-matched to 116 OPCAB patients. Operative duration was longer in MICS-CABG (238.9 ± 65 vs. 175.0 ± 48 min; p < 0.001). However, ventilation time (112.2 ± 56.9 vs. 116.9 ± 64.7 min; p = 0.59), hospital LOS (8.7 ± 4.0 vs. 8.6 ± 4.1 days; p = 0.78), and unplanned ICU transfer (0.9% vs. 2.6%; p = 0.37) were comparable. Postoperative complications, transfusion rates, pain scores, and in-hospital mortality also did not differ significantly. Conclusions: Within a structured ERACS pathway incorporating early extubation and ICU bypass, MICS-CABG and OPCAB achieved similar short-term recovery outcomes despite differences in operative complexity. These findings suggest that ERACS can provide a consistent postoperative recovery framework across both revascularization strategies. Full article

Background: Weaning failure remains a major challenge in intensive care practice, often reflecting the interplay between systemic catabolism and skeletal muscle wasting. The blood urea nitrogen-to-creatinine (BUN/Cr) ratio is a routinely available biochemical index influenced by renal handling, hemodynamic status, protein metabolism, and muscle mass, and has been associated with adverse outcomes in critical illness. This study aimed to evaluate the association between BUN/Cr ratio, weaning outcomes, and ultrasound-based rectus femoris thickness. Methods: This retrospective observational study included 42 mechanically ventilated adults admitted to the medical ICU of Marmara University between December 2024 and September 2025. Rectus femoris thickness was measured via bedside ultrasonography at the time of the spontaneous breathing trial (SBT). Weaning success was defined as extubation without reintubation, death, or need for NIV/HFNO due to respiratory distress within 7 days. Laboratory and clinical variables—including BUN/Cr ratio, SOFA, APACHE II, mNUTRIC, and albumin—were recorded. Multivariable logistic regression and receiver operating characteristic (ROC) analyses were performed. Results: Weaning failure occurred in 13 patients (31.0%). These patients had higher BUN/Cr ratios (58.7 [44.6–76.9] vs. 39.7 [23.8–49.2], p = 0.007) and lower rectus femoris thickness (6.2 [5.4–7.0] vs. 7.8 [6.9–8.6] mm, p = 0.021). The BUN/Cr ratio independently predicted weaning failure (OR 1.07; 95% CI 1.01–1.14; p = 0.024). ROC analysis identified a BUN/Cr cut-off of 44.6 (AUC = 0.76) for weaning failure. An exploratory composite metabolic–muscle indicator (MMI), combining BUN/Cr ratio and rectus femoris thickness, demonstrated higher discriminative performance in this cohort (AUC = 0.81). Conclusions: An elevated BUN/Cr ratio was independently associated with weaning failure and lower rectus femoris thickness in this cohort. Given the observational design and potential confounding, these findings should be interpreted as hypothesis-generating. Combined biochemical and ultrasound-based assessment highlights the potential value of integrating metabolic and morphologic information when characterizing patients at risk for weaning failure. However, whether incorporation of such markers into clinical decision-making improves weaning outcomes requires prospective validation. Full article

Catalytic oxidation has proven to be an effective method for treating low-concentration ventilation air methane. However, regenerative catalytic oxidizers (RCOs) used for ventilation air methane (VAM) treatment often face engineering challenges such as low oxidation efficiency and uneven heat transfer, which limit their overall performance and reliability. This study proposes a CFD-based structural optimization approach that couples flow field, temperature field, concentration field, and chemical reaction processes to systematically analyze the heat transfer and reaction mechanisms within the RCO. The key operational parameters of the reaction process were further discussed. The research focuses on improving temperature uniformity and enhancing methane conversion efficiency to achieve superior thermal efficiency and more effective methane mitigation. The results show that increasing the number of the electric heating rods and rearranging their configuration improved the temperature uniformity of the catalyst layer by 0.2842 (from 0.5462 to 0.8304). Additionally, the installation of a flow distribution plate further enhanced temperature uniformity by 0.1481 (from 0.8304 to 0.9785). As a result of these structural optimizations, the methane conversion rate of the new system increased significantly from 65% to 95%. This study offers valuable insights for future RCO design and optimization, paving the way for more efficient and reliable VAM treatment technologies. Full article

Air emissions from livestock farming, particularly ammonia (NH₃) and particulate matter (PM_2.5 and PM₁₀), constitute a major environmental and occupational health concern. The aim of this work was to assess the compliance with the Verification of Environmental Technologies for Agricultural Production (VERA) protocol in livestock emission monitoring studies and to propose the Adherence VERA Index (AVI) as a novel quantitative tool for standardizing methodological evaluation. A literature search was conducted in PubMed and Scopus, identifying 26 eligible studies published between January 2012 and June 2025. Data were extracted on farm characteristics, analytical methods, environmental variables, and emission outcomes, and evaluated across the five VERA protocol domains. The review revealed substantial methodological heterogeneity and overall suboptimal compliance with the VERA protocol, with frequent deficiencies in the reporting of key parameters such as ventilation rate, sampling strategy, and emission estimation methods. In this context, the AVI, by condensing core VERA requirements into a concise and operational metric, may facilitate protocol uptake and improve reporting compliance compared with the full VERA framework. Notably, several studies reported NH₃, PM_2.5 and PM₁₀ concentrations exceeding occupational and environmental exposure thresholds, particularly in swine and poultry farms, highlighting critical risks to workers’ health. These findings underscore the need for enhanced standardization, integration of occupational health metrics, and improved air quality monitoring to ensure reliable exposure assessment and to safeguard both environmental and worker health in the livestock sector. Full article

Introduction. Patent ductus arteriosus (PDA) is the most common cardiac anomaly in preterm newborns and may aggravate respiratory disease. Invasive closure options after failure of medical treatment include surgical ligation (SL) and transcatheter closure (TCC). Reports on side effects of intravenous contrast media are scarce. Methods. In this retrospective single-center study, we compared 35 preterm infants below 1500 g birth weight undergoing SL with 35 matched infants undergoing TCC. Outcomes were procedural success, complications and postprocedural ventilation. Results. Closure success was high in both groups (97% SL vs. 86% TCC, p = 0.106). One SL patient underwent re-operation after accidental clipping of the left pulmonary artery, and eight patients (24%) had endoscopy-diagnosed vocal cord palsy after SL. Six TCC patients had complications that required further action, including device embolization, device failure and one case of late device migration that resulted in aortic arch obstruction requiring intervention, and 4 TCC patients developed necrotizing enterocolitis (NEC)-like disease within 24 h, requiring surgery in one patient. SL was associated with longer duration of mechanical ventilation (24 h vs. 144 h, p < 0.001), as opposed to TCC, and higher rates of bronchopulmonary dysplasia (86% vs. 53%, p = 0.004). Discussion. Both techniques achieve high success but differ in complication profiles. TCC may reduce respiratory morbidity. NEC-like disease (probably linked to intravenous administration of contrast agents) warrants further investigation. Full article

This study focuses on the operational energy consumption of existing thermal power plant buildings in China’s hot-summer, cold-winter regions. Unlike conventional civil buildings, thermal power plant structures feature intense internal heat sources, large spatial dimensions, specialized ventilation requirements, and year-round industrial waste heat. Consequently, the energy consumption characteristics and energy-saving logic of their building envelopes remain understudied. This paper innovatively employs a combined experimental approach of field monitoring and energy consumption simulation to quantify the actual thermal performance of building envelopes (particularly exterior walls, doors, and windows) under current operating conditions, identifying key components for energy-saving retrofits of the main plant building envelope. Due to the fact that most thermal power plants were designed relatively early, their envelope structures generally have problems such as poor insulation performance and insufficient air tightness, resulting in severe energy loss under extreme weather conditions. An energy consumption simulation model was established using GBSEARE software. By focusing on heat transfer coefficients of exterior walls and windows as key parameters, a design scheme for energy-saving retrofits of building envelopes in thermal power plants located in hot-summer, cold-winter regions was proposed. The results show that there is a temperature gradient along the height direction inside the main plant, and the personnel activity area in the middle activity level of the steam engine room is the most unfavorable area of the thermal environment of the steam engine room. The heat transfer coefficient of the envelope structure does not meet the current code requirements. The over-standard rate of the exterior walls is 414.55%, and that of the exterior windows is 177.06%. An energy-saving renovation plan is proposed by adopting a composite color compression panel for the external wall, selecting 50 mm flame-retardant polystyrene EPS foam board for the heat preservation layer, adopting 6 high-transmittance Low-E + 12 air + 6 plastic double-cavity for the external windows, and adding movable shutter sunshade. The energy-saving rate of the building reached 55.32% after the renovation. This study provides guidance for energy-efficient retrofitting of existing thermal power plants and for establishing energy-efficient design standards and specifications for future new power plant construction. Full article

This paper analyzes smoke control strategies in high-rise building stairwells, with particular focus on their application to existing buildings without smoke exhaust openings at the top of the stairwell. This study is necessary to support the optimization of fire safety in a wide range of existing high-rise buildings in Bucharest, Romania, where stairwells operate without upper smoke vents. The scientific challenge addressed is the comparative evaluation of natural ventilation and mechanical pressurization applied at the lower part of the stairwell in order to assess their influence on smoke and heat propagation. The motivation of this work is related to emergency response, as firefighters require a clear understanding of smoke movement and evacuation conditions depending on the fire location and ventilation mode. Three-dimensional CFD simulations were performed, using a fire source validated against experimental data, to analyze temperature, pressure, airflow velocity, visibility, and toxic gas concentration for different fire-floor locations. The results show that natural ventilation alone is ineffective, while single-point mechanical pressurization improves conditions only during the early fire stage. The findings contribute to better-informed firefighter decision-making by clarifying stairwell conditions during intervention in existing high-rise buildings. Full article

Museums open to the public must reconcile heritage preservation requirements with energy-conscious microclimate management and visitors’ environmental experience. In historic buildings, indoor conditions are typically controlled primarily for preventive conservation, while opportunities for detailed assessment of human comfort are often limited by existing monitoring systems and operational constraints. This study investigates visitors’ perceptions of thermal conditions and indoor air quality (IAQ) in two branches of the National Museum in Krakow (NMK) characterized by different microclimate-control strategies: the mechanically ventilated and air-conditioned Cloth Hall and the predominantly passively controlled Bishop Erazm Ciołek Palace. A pilot survey was conducted in spring 2023 to capture subjective assessments of thermal sensation and perceived IAQ. These perceptions were contextualized using long-term air temperature and relative humidity data (2013–2023) routinely monitored for conservation purposes. Environmental data were analyzed to assess the stability of indoor conditions and to provide background for interpreting survey responses, rather than to perform a normative evaluation of thermal comfort. The results indicate that visitors frequently perceived the indoor environment as slightly warm and reported lower air quality in the Palace, where air was often described as stale or stuffy. These perceptions occurred despite relatively small differences in monitored air temperature and relative humidity between the two buildings. The findings suggest that ventilation strategy, air exchange effectiveness, odor accumulation, room configuration, and lighting conditions may influence perceived environmental quality more strongly than temperature or humidity alone. Although limited in scope, this pilot study highlights the value of incorporating visitor perception into discussions of energy-conscious microclimate management in museums and indicates directions for further multidisciplinary research. Full article

Conventional Heating, Ventilation, and Air Conditioning (HVAC) systems in electric vehicles significantly penalize the driving range due to high power consumption, particularly during heating operation. While R744 heat pump systems are gaining traction as a promising solution for addressing this limitation, their ventilation strategies pose a complex trade-off between energy consumption and in-vehicle air quality (IAQ). Specifically, the continuous use of recirculation mode to enhance energy efficiency can lead to the accumulation of occupant-exhaled CO₂ conversely, introducing fresh air to dilute CO₂ results in both an energy penalty and the infiltration of external pollutants. To analyze this complex trade-off under varying fresh-to-recirculated air ratios, this study developed a model of an automotive R744 HVAC system and IAQ considering CO₂ and PM2.5 using the 1D simulation tool AMEsim. The system model was validated against experimental data from the literature, demonstrating high fidelity with overall relative errors consistently within 10%. The analysis of the ventilation strategy reveals a distinct IAQ trade-off: increased fresh air intake effectively diluted in-cabin CO₂ concentrations but simultaneously increases the infiltration of external PM2.5. In terms of energy efficiency, during cooling mode, increased fresh air intake reduces the system $COP$ from 1.77 to 1.54 and increases total battery consumption by up to 57%. Conversely, in heating mode, the increased fresh air intake enhances heat exchanger efficiency, leading to a rise in the COP by up to 9%. However, due to the higher overall thermal load, the total battery consumption still increases by up to 24%. Full article