Direct air capture of CO2 using biochar prepared from sewage sludge: Adsorption capacity and kinetics.

As an emerging carbon-negative emission technology, carbon dioxide (CO2) capture from the air is an essential safeguard for alleviating global warming. Sludge-activated carbon with excellent mesoporous structure is a potential material for CO2 capture. In this paper, the amino modified sewage sludge materials were used to prepare the porous CO2 adsorbent from air. The effect of preparation conditions on the microstructure of sewage sludge-based activated carbon materials was analyzed by microstructural characterization, and the impacts of activator, pyrolysis temperature, and the concentration of modifier on the CO2 adsorption performance of sewage sludge-based activated carbon materials were also systematically investigated. The results show that the pyrolysis temperature, the type of activator and the modifier concentration significantly affect the adsorption performance of sewage sludge-based CO2 adsorption materials. Among them, the sewage sludge-based CO2 adsorption material prepared with solid NaOH as an activator, with an activation temperature of 600 °C and loading concentration of 20 %, exhibited the best performance, that is the CO2 adsorption capacity reached 1.17 mmol/g, and the half time is about four min, which shows better performance, compared with other adsorbents for CO2 capture from air. The research results can reduce CO2 emissions on the one hand, and on the other hand, realize the resourceful utilization of sewage sludge, which sheds light on "treating the wastes with wastes".

Multi-scale simulations of pulmonary airflow based on a coupled 3D-1D-0D model.

Pulmonary airflow simulation is a valuable tool for studying respiratory function and disease. However, the respiratory system is a complex multiscale system that involves various physical and biological processes across different spatial and temporal scales. In this study, we propose a 3D-1D-0D multiscale method for simulating pulmonary airflow, which integrates different levels of detail and complexity of the respiratory system. The method consists of three components: a 3D computational fluid dynamics model for the airflow in the trachea and bronchus, a 1D pipe model for the airflow in the terminal bronchioles, and a 0D biphasic mixture model for the airflow in the respiratory bronchioles and alveoli coupled with the lung deformation. The coupling between the different components is achieved by satisfying the mass and momentum conservation law and the pressure continuity condition at the interfaces. We demonstrate the validity and applicability of our method by comparing the results with data of previous models. We also investigate the reduction in inhaled air volume due to the pulmonary fibrosis using the developed multiscale model. Our method provides a comprehensive and realistic framework for simulating pulmonary airflow and can potentially facilitate the diagnosis and treatment of respiratory diseases.

A Biomechanical Simulation of Forearm Flexion Using the Finite Element Approach.

Upper limb movement is vital in daily life. A biomechanical simulation of the forearm with consideration of the physiological characteristics of the muscles is instrumental in gaining deeper insights into the upper limb motion mechanisms. In this study, we established a finite element model of the forearm, including the radius, biceps brachii, and tendons. We simulated the motion of the forearm resulting from the contraction of the biceps brachii by using a Hill-type transversely isotropic hyperelastic muscle model. We adjusted the contraction velocity of the biceps brachii muscle in the simulation and found that a slower muscle contraction velocity facilitated forearm flexion. Then, we changed the percentage of fast-twitch fibers, the maximum muscle strength, and the neural excitation values of the biceps brachii muscle to investigate the forearm flexion of elderly individuals. Our results indicated that reduced fast-twitch fiber percentage, maximum muscle strength, and neural excitation contributed to the decline in forearm motion capability in elderly individuals. Additionally, there is a threshold for neural excitation, below which, motion capability sharply declines. Our model aids in understanding the role of the biceps brachii in forearm flexion and identifying the causes of upper limb movement disorders, which is able to provide guidance for enhancing upper limb performance.

Automated detection of hippocampal sclerosis: Comparison of a composite MRI-based index with conventional MRI measures.

PURPOSE: This study aims to compare the performance of an MRI-based composite index (HSI) with conventional MRI-based measures in hippocampal sclerosis (HS) detection and postoperative outcome estimation. METHODS: Seventy-two temporal lobe epilepsy (TLE) patients with pathologically confirmed HS and fifteen TLE patients without HS were included retrospectively. The T1-weighted and FLAIR images of these patients were processed with AccuBrain to quantify the hippocampal volume (HV) and the hippocampal FLAIR signal. The HSI index that considered both HV and hippocampal FLAIR signal was also calculated. Two experienced neuropathologists rated the HS severity with the resected tissue and reached an agreement for all cases. The asymmetry indices of the MRI measures were used to lateralize the sclerotic side, and the original MRI measures were applied to detect HS vs. normal hippocampi. Operating characteristic curve (ROC) analyses were performed for these predictions. We also investigated the sensitivity of the ipsilateral MRI measures in characterizing the pathological severity of HS and the associations of the MRI measures with postoperative outcomes (Engel class categories). RESULTS: With the optimal cutoffs, the asymmetry indices of HSI and HV both achieved excellent performance in differentiating left vs. right HS (accuracy = 100 %), and the absolute value of the asymmetry index of HSI performed best in differentiating unilateral vs. bilateral HS (accuracy = 91.7 %). Regarding the detection of HS, HSI performed better in sensitivity (94.4 % vs. 87.5 %) while HV performed better in specificity (93.6 % vs. 89.4 %) when the contralateral site of unilateral HS and both sides of non-HS patients were considered as the normal reference, and HSI performed even better than HV when only both sides of non-HS patients were considered as the normal reference (AUC: 0.956 vs. 0.934, p = 0.038). The ipsilateral HSI presented the strongest association with the pathological rating of HS severity (r = 0.405, p < 0.001). None of the ipsilateral or contralateral MRI measures was associated with the postoperative outcomes. Among the asymmetry indices, only the absolute value of the asymmetry index of HV presented a significant association with the Engel classifications for the Year 2∼3 visit (r = -0.466, p = 0.004) or the latest visit with >1 year follow-up (r = -0.374, p = 0.003) while controlling for disease duration and follow-up duration. CONCLUSION: The HSI index and HV presented comparable good performance in HS detection, and HSI may have better sensitivity than HV in differentiating pathological HS severity. Higher magnitude of HV dissymmetry may indicate better post-surgical outcomes for HS patients.

Upper esophageal sphincter augmentation reduces pharyngeal reflux in nasogastric tube-fed patients.

OBJECTIVES/HYPOTHESIS: Aspiration of gastric refluxate is one of the most commonly observed complications among long-term nasogastric tube (NGT) fed patients. The upper esophageal sphincter (UES) pressure barrier is the main defense mechanism against pharyngeal reflux of gastric contents. Our objective was to investigate the efficacy and safety of the UES assist device (UES-AD) in preventing gastric reflux through the UES in long-term NGT-fed patients. STUDY DESIGN: Self-Controlled Case series. METHODS: We studied 10 patients (mean age = 90.6 ± 3.4 years, four females) with dysphagia caused by stroke or dementia who were fed for 0.5 to 5 years (median = 3 years) by NGT. External pressures of 20 to 30 mm Hg were applied by using a handmade UES-AD, which was started 2 hours after the beginning of NGT infusion and was alternated between periods of 2 hours on and 2 hours off, for a total of 12 hours. Placement of the impedance sensors within the UES was guided by high-resolution manometry. Trans-UES and intraesophageal reflux events were recorded by using 24-hour combined pH-impedance measurements. RESULTS: No aspiration pneumonia events were noted in the period 1 month before or during the study in any of the cohort. Baseline UES pressure averaged 17.5 ± 9.4 mm Hg and was increased to 38.9 ± 11.9mm Hg after application of the UES-AD. Overall frequency of trans-UES reflux decreased significantly with the UES-AD compared to without (0.8 ± 0.9 vs. 3.3 ± 2.8, P < .05 for the 12-hour study period). There was no effect of the UES-AD on esophageal reflux events (7.4 ± 4.4 vs. 6.4 ± 3.0, P > .05). CONCLUSIONS: UES-AD significantly decreases the number of trans-UES reflux events and can potentially reduce the aspiration risk associated with NGT feeding. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:1310-1315, 2018.

Anatomic predictors of retropalatal mechanical loads in patients with obstructive sleep apnea.

BACKGROUND: The retropalatal airway is one of the most collapsible sites during sleep in patients with obstructive sleep apnea (OSA). The primary anatomical contributors to increased collapsibility in the retropalatal segment remain unclear. OBJECTIVES: This study seeks to investigate how the balance between pharyngeal soft tissues and the bony enclosure influences retropalatal mechanical loads in patients with OSA. METHODS: The segmental mechanical load of the retropalatal pharynx was determined by the region's critical closing pressure in 30 anesthetized, paralyzed and intubated subjects with OSA. The volumetric anatomical parameters of the retropalatal airway were evaluated using magnetic resonance imaging, and their associations with retropalatal closing pressures were analyzed. RESULTS: Increased retropalatal closing pressure was associated with the increased proportion of volumetric pharyngeal soft tissues to the surrounding cervicomandibular bony frame (r = 0.791, p < 0.001), enlarged soft tissues of the lateral wall (r = 0.752, p < 0.001) and soft palate (r = 0.726, p < 0.001). The decreased volume of the nasopharynx (r = -0.650, p < 0.001) and pharyngeal cavity (r = -0.653, p < 0.001) indicated a relatively higher retropalatal closing pressure. The multivariate linear regression model demonstrated that the proportion of retropalatal soft tissues to the bony frame and volume of the soft palate predicted 69.4% of the variability in closing pressure (F = 30.674, p < 0.001). CONCLUSIONS: The increased volumetric proportion of pharyngeal soft tissue to the bone enclosure may be an important contributor to increased retropalatal mechanical loads.