Specific Volume Changes Research Articles

Effect of supercritical carbon dioxide on pore structure and methane adsorption of shale with different particle sizes

Supercritical carbon dioxide (SCCO2) fracturing significantly enhances shale gas recovery, which is influenced by particle size. We soaked shale in SCCO2 and investigated the impact of SCCO2 on different particle sizes. Large-particle shales showed the largest percentage changes in specific surface area and total pore volume (54.11 %, 87.87 %; 58.59 %, 76.32 %) followed by small-particle size shales. This trend was also observed in other pore structure parameters. The particle-size effect is: Large-particle shale, with abundant microfractures, enhances SCCO2 flow and pore alteration. Small-particle shale's high specific surface area facilitates SCCO2 penetration. Medium-particle shale is less affected due to balanced interactions of these factors. Methane is primarily found in large and medium pores and microfractures. Methane adsorption in shale mainly involves multi-layer adsorption. Following SCCO2 treatment, pore fractures narrowed, increasing the proportion of methane molecules adsorbed as a single-layer. This study is crucial for evaluating the fracturing effects on shale gas wells.

Numerical investigation in effects of refrigerants’ thermodynamic properties on performance of supersonic ejector

ABSTRACT Using zeotropic mixtures with unique temperature glide characteristics as the working medium in heat-driven ejector refrigeration system will potentially reduce the irreversible losses in heat exchange process. However, the intrinsic link between the pure/mixture refrigerants’ thermophysical properties and the entrainment performance of supersonic ejector has not yet been elucidated. In this study, a novel ejector CFD model is established by coupling the real-gas thermodynamic equation and species transport equation, then the relationships between thermophysical properties of pure/mixture refrigerants and ejector’s dimensionless operational parameters were thoroughly investigated. The results indicated that the ejector expansion ratio rises as primary flow inlet temperature or refrigerant’s normal boiling point increases, while the dimensionless parameters of primary nozzle are relatively insensitive to the variation of primary flow inlet temperature and refrigerant’s boiling point, resulted in changes of supersonic jet expansion behaviour. Moreover, the specific volume and adiabatic index change characteristics resulted in minor fluctuations of primary nozzle’s dimensionless parameters. When the bubble point temperature is fixed at 30℃ in the condenser, the saturated vapor/liquid phase pressure glide characteristics of R600a/R1234ze mixture may lead to an increasement of ejector’s compression ratio.

Incorporation of spray-dried encapsulated bioactive peptides from coconut (Cocos nucifera L.) meal by-product in bread formulation.

This study aimed to stabilize and mask the bitterness of peptides obtained from the enzymatic hydrolysis of coconut-meal protein with maltodextrin (MD) and maltodextrin-pectin (MD-P) as carriers via spray-drying. Essential (~35%), hydrophobic (~32%), antioxidant (~15%), and bitter (~45%) amino acids comprised a significant fraction of the peptide composition (with a degree of hydrolysis of 33%). The results indicated that the peptide's production efficiency, physical and functional properties, and hygroscopicity improved after spray-drying. Morphological features of free peptides (fragile and porous structures), spray-dried with MD (wrinkled with indented structures), and MD-P combination (relatively spherical particles with smooth surfaces) were influenced by the process type and feed composition. Adding free and microencapsulated peptides to the bread formula (2% W/W) caused changes in moisture content (35%-43%), water activity (0.89-0.94), textural properties (1-1.6 N), specific volume (5.5-6 cm3/g), porosity (18%-27%), and color indices of the fortified product. MD-P encapsulated peptides in bread fortification resulted in thermal stability and increased antioxidant activity (DPPH and ABTS+ radical scavenging: 4.5%-39.4% and 31.6%-46.8%, respectively). MD-P (as a carrier) could maintain sensory characteristics and mask the bitterness of peptides in the fortified bread. The results of this research can be used to produce functional food and diet formulations.

Specific volume changes upon thermal phase transition of sub-microliter volumes of lipids and membrane proteins by a QCM nanopore sensor

Specific volume changes upon thermal phase transition of sub-microliter volumes of lipids and membrane proteins by a QCM nanopore sensor

Sol-gel synthesis of zirconia-based nanoparticles from the side product of tin mining

Indonesia has been one of the world’s primary source of tin since the early of 19th century. Bangka island has the largest tin abundant with a side product is zircon sand (ZrSiO4). The existence of zircon (ZrSiO4) is mostly associated with some of the valuable oxide compounds (VOC) and rare earth oxides (REO). The zirconia powders were synthesized from the zircon sand of PT. Timah Tbk by caustic fusion method followed by sol-gel method. The raw material zircon sand and as-synthesized zirconia were characterized through x-ray fluorescence (XRF), x-ray diffraction (XRD), surface area analysis and porositymeter, thermogravimetric and differential scanning calorimetry analysis (TG-DSC), fourier transform infra-red (FTIR) and scanning electron microscopy (SEM) techniques. The results show that zircon sand from PT Timah Tbk contains some of VOCs, such as ZrSiO4, ZrO2, HfO2, SiO2, Al2O3, TiO2, Fe2O3 and some REOs, such as La2O3, Y2O3, Nb2O5. The fusion temperatures varied from 600 to 800 °C which resulted in an increase of the purity of ZrO2 to 76% based on the XRF analysis. The surface area analysis and porositymeter results showed the significant change in specific surface area, pore size and pore volume of as-synthesized zirconia. The specific surface area increased dramatically from 0.28 m2/g to 173.97, 125.18, and 102.14 m2/g, at fusion temperatures of 600, 700, and 800 °C, respectively. The average particle size of as-synthesized zirconia showed the significant change from 21.31μm to 34.48 nm. The results of this work open new opportunities for the development of zirconia-based nanoparticles from the side product of tin mining.

The effect of inhaled extrafine beclometasone dipropionate/formoterol fumarate/glycopyrronium bromide on distal and central airway indices, assessed using Functional Respiratory Imaging in COPD (DARWiIN)

BackgroundThis study, in patients with symptomatic chronic obstructive pulmonary disease (COPD), explored switching therapy from non-extrafine high-dose inhaled corticosteroid/long-acting β2-agonist (ICS/LABA; fluticasone propionate/salmeterol [FP/SLM]) to extrafine medium-dose beclometasone dipropionate/formoterol fumarate dihydrate/glycopyrronium (BDP/FF/G), both via dry-powder inhaler. Functional Respiratory Imaging, a quantitative computed tomography method with 3D reconstructions of pulmonary anatomy, was used to assess airway geometry and lung function.MethodsPatients receiving a stable ICS/LABA regimen for ≥ 8 weeks were switched to FP/SLM 500/50 µg, one inhalation twice-daily (high-dose ICS) for 6 weeks. After baseline assessments (Visit 2 [V2]), therapy was switched to BDP/FF/G 100/6/10 µg, two inhalations twice-daily (medium-dose ICS) for 6 weeks, followed by V3. The primary endpoints were percentage changes in specific image-based airway volume (siVaw) and resistance (siRaw) from baseline to predose at V3 (i.e., chronic effects), assessed at total lung capacity (TLC) in central and distal lung regions. Secondary endpoints included siVaw and siRaw changes from pre-dose to post-dose at V2, and from pre-dose to post-dose at V3 at TLC (i.e., acute effects), and chronic and acute changes in siVaw and siRaw at functional residual capacity (FRC). Pre-dose forced expiratory volume in 1 s (FEV1) and COPD Assessment Test (CAT) were also assessed.ResultsThere were no significant changes in pre-dose siVaw or siRaw at TLC from baseline to V3, although at FRC there was a significant decrease in mean siRaw in the distal airways (− 63.6%; p = 0.0261). In addition, in the distal airways there were significant acute effects at TLC on mean siVaw and siRaw (siVaw: 39.8% and 62.6%; siRaw: − 51.1% and − 57.2%, V2 and V3, respectively; all p < 0.001) and at FRC at V2 (siVaw: 77.9%; siRaw: − 67.0%; both p < 0.001). At V3, the mean change in pre-dose FEV1 was 62.2 mL (p = 0.0690), and in CAT total score was − 3.30 (p < 0.0001).ConclusionsIn patients with symptomatic COPD receiving high-dose ICS/LABA, adding a long-acting muscarinic antagonist while decreasing the ICS dose by switching to medium-dose extrafine BDP/FF/G was associated with improved airway indices, especially in the distal airways, together with improvements in respiratory health status.Trial registration ClinicalTrials.gov (NCT04876677), first posted 6th May 2021

CHANGES OF SURFACE CHARACTERISTICS&#x0D; AND PORE SIZE DISTRIBUTION OF PETROLEUM COKE&#x0D; DURING ITS CALCINATION IN THE PRESENCE OF POTASSIUM HYDROXIDE

Change of surface properties and pore distribution in petroleum coke at carbonization stage at 900 °C in presence&#x0D; of potassium hydroxide has been studied. CO2 adsorption and desorption isotherms at 298 K have been obtained&#x0D; for samples of raw and carbonized petroleum coke without and with potassium hydroxide addition. For pore shape and&#x0D; size distribution analysis GCMC (Grand Canonical Monte Carlo) computer simulation method has been used. Regularity&#x0D; of changes in volume, specific surface area and distribution of cylindrical and slit-shaped pores depending on the&#x0D; amount of potassium hydroxide added prior to carbonization stage in petroleum coke has been revealed. Extreme dependence&#x0D; of change in specific surface area and pore volume on potassium hydroxide content in carbonized coke has&#x0D; been identified. It has been found that addition of potassium hydroxide of less than 50% wt. reduces pore quantity and&#x0D; specific surface area of carbonized coke. The main contribution to the coke specific surface area is made by slit-shaped&#x0D; and cylindrical mesopores, as well as cylindrical macropores. It has been shown that by varying the amount of potassium&#x0D; hydroxide added to petroleum coke prior to its carbonization it is possible to regulate the formed pores distribution&#x0D; in terms of shape and size.

Roasted-sprouted lentil flour as a novel ingredient for wheat flour substitution in breads: Impact on dough properties and quality attributes

Flours from lentil seeds, raw or sprouted (either lyophilized or roasted before grinding), were used for wheat flour substitution in breads. The physicochemical properties of the obtained flours and doughs as well as bread quality attributes and staling were examined. FTIR spectroscopy revealed that sprouting altered the secondary structure of the lentil protein matrix by decreasing β-turns and random coils, and increasing β-sheets, α-helices and aggregates, while roasting subsequently eliminated these changes. Calorimetry (DSC) showed that the roasted-sprouted lentil flour was partially gelatinized. Oscillatory and creep-recovery rheological tests showed that doughs fortified with roasted-sprouted lentil flour at 15 and 20% (flour basis) substitution level were more viscous and elastic. Breads made with 10% lyophilized-sprouted lentil flour exhibited the lowest specific volume, and the highest crumb hardening and starch retrogradation rates as well as the greatest increase in protein β-sheets in the composite protein-starch matrix. Instead, the formulation with 10% roasted-sprouted lentil flour did not show major changes in loaf specific volume and extent of starch retrogradation, following 4 days of storage, while exhibited significantly improved crumb textural characteristics compared to bread made with wheat flour alone, receiving the highest overall acceptability scores among all fortified products tested due to its pleasant roasted-like flavor note detected by sensory assessors. These findings suggest that a successive process of sprouting and roasting of lentil seeds could be an innovative approach to fortify wheat flour-based breads for improving their nutritional quality while maintaining desirable textural and sensorial attributes of the baked product.

Effects of Pressure and Cooling Rates on Crystallization Behavior and Morphology of Isotactic Polypropylene

Isotactic Polypropylene (iPP) is a widely used polymer due to its excellent mechanical and thermal properties, as well as its chemical resistance. The crystallization behavior of polypropylene is influenced by several factors, such as temperature, cooling rate, and pressure. The effect of pressure is significant for both scientific and technological points of view, since in important industrial processing techniques the polymer solidifies under high pressures. In this paper, the study of the effect of pressure on the crystallization kinetics of iPP was conducted using a dilatometer in the pressure range from 100 to 600 bar and under two cooling rates: 0.1 and 1 °C/s. The morphology of the samples was characterized using DSC, optical microscopy, and X-ray diffraction. The results showed that pressure had a larger effect on specific volume changes at higher temperatures (in the melt state) than at lower temperatures (in the solid state). The polymer crystallization, which determined the transition between the melt and solid state, occurred at higher temperatures with increasing pressure. The cooling rate affected the crystallization process, with higher cooling rates leading to crystallization at lower temperatures. The size of the spherulites decreased with increasing cooling rates. The crystallinity evolution curves showed a linear relationship between the crystallization temperature and pressure. The study used a Kolmogoroff–Avrami–Evans model to describe the evolution into isotropic structures, and the predictions of the model accurately described the effect of pressure and cooling rates on the final spherulite radii.

Mo2N/CoN nanotube with synergistic reaction of intercalation and conversion enables high performance lithium-ion batteries

Constructing heterostructure materials with synergistic effect of intercalation and conversion reactions has been suggested to be an effective way to achieve high-performance LIBs electrodes with high specific capacity and low volume change. Herein, a novel Mo2N/CoN nanotube material was synthesized, where the CoN component undergo a conversion reaction during cycles, while Mo2N exhibits intercalation reaction feature. Moreover, the nanotube hollow structure of Mo2N/CoN not only offers more active sites and short pathway for Li+ ions and electrons diffusion, but also effectively buffer the volume change of the material. As expected, the Mo2N/CoN nanotube anode displays excellent electrochemical properties.

Thermal Lens Measurements of Thermal Expansivity in Thermosensitive Polymer Solutions

The weak absorption of a laser beam generates in a fluid an inhomogeneous refractive index profile acting as a negative lens. This self-effect on beam propagation, known as Thermal Lensing (TL), is extensively exploited in sensitive spectroscopic techniques, and in several all-optical methods for the assessment of thermo-optical properties of simple and complex fluids. Using the Lorentz-Lorenz equation, we show that the TL signal is directly proportional to the sample thermal expansivity α, a feature allowing minute density changes to be detected with high sensitivity in a tiny sample volume, using a simple optical scheme. We took advantage of this key result to investigate the compaction of PniPAM microgels occurring around their volume phase transition temperature, and the temperature-driven formation of poloxamer micelles. For both these different kinds of structural transitions, we observed a significant peak in the solute contribution to α, indicating a decrease in the overall solution density-rather counterintuitive evidence that can nevertheless be attributed to the dehydration of the polymer chains. Finally, we compare the novel method we propose with other techniques currently used to obtain specific volume changes.

Measurement of pressure–volume–temperature diagrams based on simulated melt temperature and actual cavity pressure

Pressure–volume–temperature (pvT) diagrams illustrate the behavior of a polymer melt during injection molding and can be used to determine the optimal process parameter settings for producing quality parts. However, the measurements of pvT diagrams are costly and time-consuming and have limitations for process control. This study generated an economic pvT diagram based on sensor data and simulation analysis. To avoid the use of expensive infrared sensors and inaccurate pressure simulations, a pvT curve was constructed by combining the melting temperature, which was simulated using computer-aided engineering, and the actual cavity pressure. The specific volume of the polymer melt was then calculated using a modified Tait model. The pvT diagram could be used to investigate the changes in specific volume at various injection stages, which could be applied to quality prediction. In this study, a flat plate with uneven thickness was used as the research vehicle. The specific volume of each sensor position of the plastic component cooled to room temperature was calculated. Thereafter, a correlation analysis between the changes in specific volume and the shrinkage ratio of the plastic part was conducted. The experiment indicated that both variables were highly correlated. Therefore, monitoring changes in specific volume could predict part size. Additionally, the proposed measurements of the pvT diagram could be used to compute the cooling time, which greatly affects the quality and production efficiency of injection-molded parts. A 25-s cooling time setting demonstrated a stable molding quality compared with the traditional heat transfer formula (16 s) and the commercial simulation (17 s).

On the critical pressure pulse width for ignition of hydrogen–air and dimethyl ether–air mixtures

Under certain situations, such as a water hammer event, a volume of gas can undergo a rapid compression immediately followed by a rapid expansion, which could lead to auto-ignition under certain conditions. The goal of the present study was to investigate under which critical conditions such a pressure pulse could lead to an ignition event. To simulate the pressure pulse, a simplified Gaussian pressure pulse model was implemented in Cantera. Hydrogen–air and dimethyl ether–air mixtures were employed to study the ignition dynamics of chemical systems with a single and a double step of heat release. The numerical simulations were performed for three peak pressures of 101.3, 1013.2, and 5066 kPa, for a range of compression ratios between 5 and 45, and various pulse widths, which determine the characteristics of the pressure pulse. Depending on the width of the Gaussian pulse, either ignition or chemical quenching were observed. Critical ignition, just at the limit between ignition and quenching, is the result of the competition between chemical reaction and volumetric expansion due to the imposed specific volume changes. This competition can be summarized by the concept of critical pressure pulse width, which is an extension of the critical decay rate concept. To further investigate the mechanisms responsible for critical ignition and quenching, quantitative thermo-chemical analyses were performed for sub-critical, critical and super-critical conditions. A Damköhler number was defined as the ratio of characteristic time of expansion to ignition delay time to characterize the competition between ignition and quenching. A simplified non-dimensional pressure pulse model for which the derivative of the naperian logarithm of density was assumed to follow a linear law was established. It can be employed to derive the critical conditions for which ignition fails. The evolution of non-dimensional temperature was obtained numerically and showed the existence of a critical pulse width for successful ignition and that the location of ignition delay time moves from the expansion phase to the compression phase as the non-dimensional pulse width is increased.

Specific Brain Gray Matter Volume Changes in Pediatric Complete Spinal Cord Injury without Fracture or Dislocation Using Voxel-Based Morphometry Analysis: Preliminary Results.

This study aims to investigate the brain gray matter volume (GMV) alterations of pediatric complete thoracolumbar spinal cord injury (SCI) without fracture or dislocation (SCIWOFD) using voxel-based morphometry (VBM) analysis and assess the sensitive neuroimaging biomarkers that may be surrogate targets to enhance brain plasticity. A total of 52 pediatric subjects (age range, 6-12 years), including 25 pediatric SCIWOFD patients and 27 typically developing (TD) children were recruited. An independent two-sample t test was performed to assess between-group differences of brain GMV. Partial correlation analyses were performed to explore the correlations between GMV values and The International Standards for Neurological Classification of Spinal Cord Injury scores, age at the time of injury, time after initial SCI. Receiver operating characteristic analysis was performed to compute the sensitivity and specificity of the imaging biomarkers for pediatric SCIWOFD diagnosis. As for the results, pediatric SCIWOFD patients showed significantly decreased GMV of bilateral cerebellum lobule VIII, right middle occipital gyrus and putamen (PUT), left pallidum (PAL) and thalamus, and increased GMV of vermis III, right cerebellum lobule VI, and supramarginal gyrus. In addition, GMV of left PAL and right PUT were negatively correlated with the pinprick/light touch sensory scores in pediatric SCIWOFD patients. Finally, when using the GMV values of left PAL and right PUT in combination as the predictor, area under the curve reached the highest-0.93. These findings provided evidence that the brain undergoes GMV changes after pediatric SCIWOFD, which may suggest important targets for functional remodeling after SCI in children and provide valuable information for the development of novel and effective rehabilitation therapies in the future.

Degradation and fragmentation behavior of polypropylene and polystyrene in water

The polystyrene (PS) retrieved from the beach exhibited no change in surface texture. In contrast to it, the retrieved polypropylene (PP) had a rumpled surface texture. Highly reactive sulfate radical generated by K2S2O8 was employed as degradation initiator of PP and PS, and their degradation behavior was studied in water. The PS carbonyl index value gradually went up down, and its molecular weight (MW) curve discontinuously shifted to a lower MW with the increase of the degradation time unlike the PP. It was found that the PP microplastic production rate was approximately three time higher than the PS from weight ratio dependence on degradation time. The higher microplastic production rate of PP arose from its crystallizability. The voids were produced by change in specific volume occurring by chemi-crystallization and then provoked the cracks leading to quick fragmentation. The SEM photographs suggested that the PP microplastic size facilely reached nm order by the cracking around lamella.

Hippocampal subfield morphology in regular hemodialysis patients.

Hippocampal alterations have been implicated in the pathophysiology of cognitive impairment in hemodialysis patients. The hippocampus consists of several distinct subfields, and the molecular mechanisms underlying cognition might be associated with specific hippocampal subfield volume changes. However, this has not yet been investigated in hemodialysis patients. This study aimed to explore volumetric abnormalities in hippocampal subfields in regular hemodialysis patients. High-resolution T1-weighted structural images were collected in 61 subjects including 36 hemodialysis patients and 25 healthy controls. A state-of-the-art hippocampal segmentation approach was adopted to segment the hippocampal subfields. Group differences in hippocampal subfield volumes were assessed in Python with a statsmodels module using an ordinary least squares regression with age and sex as nuisance effects. Hemodialysis patients had significantly smaller volumes in the bilateral hippocampus (P<.05/2, Bonferroni corrected), cornu ammonis 1 (CA1), CA4, granule cell and molecular layer of the dentate gyrus, hippocampus-amygdala transition area and molecular layer of the hippocampus than healthy controls (P<.05/24, Bonferroni corrected). Hemodialysis patients also had lower volumes in the left hippocampal tail and right fimbria than healthy controls (P<.05/24, Bonferroni corrected). Hippocampal subfield volumes were associated with neuropsychological test scores, the duration of disease and hemoglobin levels. We found smaller hippocampal subfield volumes in hemodialysis patients, which were associated with impaired cognition, supporting their role in memory disturbance in the hemodialysis population. However, multiple clinical factors may have confounded the results, and therefore, the interpretation of these results needs to be cautious.

Sustainable Treatment of Emerging Organic Pollutants (Eops), Endocrine Disruption Chemicals (Edcs) from Water &amp; Waste Water and Role of AIU Online Based Distance Learning Education System to Achieve UNESCO 2030 Goals Towards Sustainable Development

Complete mineralization of EOPs including EDCs is one of the challenges towards sustainable management practice of water and waste water treatment systems. Ozone gas has been identified as an effective oxidant against mineralization of these chemicals. Optimization of factors affecting ozonolysis is vital towards mineralization of EDCs. For this kinetic study of ozonolysis degradation of EDCs in two phase gas-liquid systems is performed in a semi[1]batch reactor observing Total Organic Carbon (TOC) degradation for process optimization. Concentration of initial substances, temperature of the system and sparger/bubble size have significant effect on ozonolysis of EDCs. They are considered as dominant factors to be optimized. Temperature dependency of specific kinetic constants of model EDCs, i.e., Diclofenac Sodium (DFS) has been determined by taking into account the specific volume change due to ozone dosing. From this the activation energy for DFS has been determined to be 26.4 KJ/mol using the well known Arrhenius rate equation. These information together with sparger effect have been incorporated to find optimum values of the process variables for ozonolysis of EDCs in water and wastewater without using any catalyst so that the simplicity of the ozonolysis process can be preserved. Results obtained in work will help water treatment industries to develop sustainable ozonolysis technique to treat EDCs at optimized process condition.

The effect of antidepressant treatment on white matter integrity in Major Depression

IntroductionWhite matter abnormalities have been identified in major depressive disorder (MDD). Although several diffusion tensor imaging studies found decreased fractional anisotropy (FA) in MDD, the effect of antidepressants (AD) treatment on white matter integrity has been insufficiently studied.ObjectivesWe sought to examine the effect of AD treatment of MDD on white matter, using DTI, in responders compared to nonresponders.MethodsWe included 25 individuals with MDD (HAMD &gt;/=20) without inflammatory, unstable medical/neurological conditions or prolonged duration (&gt; 1 year),or AD or anti-inflammatory treatment &gt;/=1 week preceding first evaluation. Evaluation before treatment and at 16 weeks included depression rating scales, a cognitive battery, inflammatory markers and MRI. Desvenlafaxine was initiated at 50mg with a possible increase to 100mg at 8 weeks.ResultsChanges included: increased volume in responders in the right Inferior Fronto-Occipital fasciculus (p=0.0315) and Superior Longitudinal Fasciculus part 3 (p=0.0050); in remitters in the right Inferior Fronto-Occipital fasciculus (p=0.0359) and Superior Longitudinal Fasciculus part 2 (p&lt;0.05) and 3 (p=0.0481); decreased volume in responders in the left Superior Longitudinal Fasciculus part 1 (p=0.0147) and left Corona Radiata(p&lt;0.05); and in remitters in the left Superior Longitudinal Fasciculus part 1 (p=0.0109) and the Corpus Callosum part 5 (p&lt;0.05); decreased FA in the right Cortico Spinal Tract in remitters (p=0.0175) and responders (p=0.0272), and an increase in FA in the left Uncinate Fasciculus in nonremitters (p=0.0493). These results lose significance following Bonferroni correction.ConclusionsOverall, AD treatment of MDD was not associated with significant changes in FA, whole brain, or specific tract volume in this study.DisclosureThis research was funded by Pfizer Canada.

Computed Tomography Registration-Derived Regional Ventilation Indices Compared to Global Lung Function Parameters in Patients With COPD.

CT registration-derived indices provide data on regional lung functional changes in COPD. However, because unlike spirometry which involves dynamic maximal breathing maneuvers, CT-based functional parameters are assessed between two static breath-holds, it is not clear how regional and global lung function parameters relate to each other. We assessed the relationship between CT-density change (dHU), specific volume change (dsV), and regional lung tissue deformation (J) with global spirometric and plethysmographic parameters, gas exchange, exercise capacity, dyspnoea, and disease stage in a prospective cohort study in 102 COPD patients. There were positive correlations of dHU, dsV, and J with spirometric variables, DLCO and gas exchange, 6-min walking distance, and negative correlations with plethysmographic lung volumes and indices of trapping and lung distension as well as GOLD stage. Stepwise regression identified FEV1/FVC (standardized β = 0.429, p < 0.0001), RV/TLC (β = −0.37, p < 0.0001), and BMI (β = 0.27, p=<0.001) as the strongest predictors of CT intensity-based metrics dHU, with similar findings for dsV, while FEV1/FVC (β = 0.32, p=<0.001) and RV/TLC (β = −0.48, p=<0.0001) were identified as those for J. These data suggest that regional lung function is related to two major pathophysiological processes involved in global lung function deterioration in COPD: chronic airflow obstruction and gas trapping, with an additional contribution of nutritional status, which in turn determines respiratory muscle strength. Our data confirm previous findings in the literature, suggesting the potential of CT image-based regional lung function metrics as the biomarkers of disease severity and provide mechanistic insight into the interpretation of regional lung function indices in patients with COPD.

Sea Surface Height Changes due to the Tropical Cyclone-Induced Water Mixing in the Yellow Sea, Korea

Sea surface height changes due to the tropical cyclone (TC)-induced water mixing in the Yellow Sea, Korea, were investigated using temperature and salinity profile data obtained by two Argo floats during the summer and fall of 2018 and 2020. Strong winds and low pressure, which are important characteristics of TCs, caused horizontal and vertical sea surface water movement and induced water mixing. This caused an increase in mixed layer depth, a decrease in water density, and an increase in specific volume. Specific volume changes related to the water steric effect were directly linked to sea surface height changes. During the TC Soulik (1819) period, the thermocline deepened by more than 10 m, and the steric sea level was increased by more than 3 cm. Other TC cases, such as Jebi (1821), Trami (1824), and Kong-Rey (1825), showed sea level increases of 1–2 cm. In 2020, 3 TCs–Bavi (2008), Maysak (2009), and Haishen (2010)—showed minor sea level increases (about 0.5–1 cm) because of weak mixing due to their high moving speeds or weak impacts. As a post-TC impact, the water mixing could cause a rise in sea levels due to the steric effect of seawater.