Gas Analysis Research Articles

Feasibility analysis for bio-natural gas generated from high-concentration organic wastewater

Feasibility analysis for bio-natural gas generated from high-concentration organic wastewater

Suprathermal corrections on galactic cosmic rays driven magnetohydrodynamic waves and gravitational instability in astrophysical plasmas

The interaction of two populations of highly energetic cosmic rays (CRs) and suprathermal kappa gas in the astrophysical systems manifests exciting features of low-frequency magnetohydrodynamic (MHD) waves and instabilities. Contrary to the previous works on waves and instability analysis in Maxwellian gas, this paper investigates the effects of suprathermal corrections on the CR driven MHD waves and gravitational (Jeans) instability using the kappa distribution function. The equation of state for a kappa gas, including spectral κ− index, is considered in the CR-plasma interactions using the hydrodynamic fluid–fluid approach. The modified dispersion properties of fast, slow, and pure Alfvén waves and Jeans instability have been discussed in a suprathermal gas in astrophysical environments. The suprathermal corrections enhance the phase speed of the fast mode of MHD waves which is found to be greater in the suprathermal gas (κ>3/2) and smaller in the Maxwellian gas (κ→∞). In the absence of CR diffusion, the Jeans instability criterion is modified due to the simultaneous presence of CR pressure and suprathermal corrections. However, in the presence of CR diffusion, only suprathermal corrections modify the Jeans instability criterion. The suprathermal gases with higher degrees of freedom require large values of the Jeans wavenumber to produce gravitational instability and make the system more unstable. The suprathermal corrections along with modified thermal speed stabilize the growth rate of Jean instability, supporting the gravitational collapse of non-thermal gas in astrophysical systems.

Correlation between cardiotocography during the active phase of the second stage of labour and neonatal blood gas analysis

Correlation between cardiotocography during the active phase of the second stage of labour and neonatal blood gas analysis

Prevalence and Risk Factors of Pulmonary Embolism in COPD Patients Complicated with Secondary Polycythemia.

This study aimed to establish the prevalence of pulmonary embolism (PE) in chronic obstructive pulmonary disease (COPD) patients with secondary polycythemia (SP) and explore the risk factors for PE in COPD patients with SP. We analyzed the prevalence of PE among COPD patients with SP who were hospitalized at Qinghai Provincial People's Hospital between January 2015 and December 2020. From January 2021 to January 2024, we enrolled patients into three groups (COPD+SP+PE, COPD+SP, and control) and performed laboratory measurements, biomarkers, echocardiography, and pulmonary function tests. Patients in the COPD+SP group received clinical treatment, and biomarkers were measured again seven days after treatment. The prevalence of PE in patients with COPD SP was 5.21%. We found that COPD+SP+PE group had significantly higher levels of erythrocyte distribution width (RDW), platelet volume distribution width (PDW), mean platelet volume (MPV), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), monocyte to large platelet ratio (MLPR), 5-hydroxytryptamine (5-HT), activated protein C (APC), urokinase-type plasminogen activator (u-PA), thrombomodulin (TM), interleukin-38 (IL-38), tissue factor (TF), and fractalkine (FKN) in contrast to COPD+SP group. Biomarkers, such as FKN, β-thromboglobulin (β-TG), APC, u-PA, TM, TF, and IL-38, were risk factors for COPD patients with SP who are complicated by PE. Clinical treatment significantly reduced the levels of β-TG, IL-38, APC, endothelin-1 (ET-1), u-PA, FKN, TM, 5-HT, and neutrophil extracellular traps (NETs) in patients with COPD+SP. PE incidence was significantly higher in patients with COPD and SP. In COPD patients with SP, routine joint detection of blood and cardiac markers, blood gas analysis, and pulmonary function tests can help to identify patients with PE. APC, u-PA, TF, FKN, TM, and IL-38 are risk factors for PE in patients with COPD and SP, and clinical treatment can effectively reduce this risk.

Fluxfinder: An R Package for Reproducible Calculation and Initial Processing of Greenhouse Gas Fluxes From Static Chamber Measurements

AbstractFluxes of greenhouse gases are a critical component of the earth's natural climate, but anthropogenic emissions have created an imbalance and resulted in global climate change. Quantifying the emission of these gases is vital to our understanding of their sources and sinks, both natural and anthropogenic. The static chamber method, in which a system of interest is enclosed, and gas concentrations are measured over time, is widely used to estimate fluxes of greenhouse gases. With the development of instruments such as infrared gas analyzers (IRGAs) supporting high‐frequency concentration data, there is a growing need for open‐source workflows to calculate fluxes. Here we present fluxfinder, an R package designed to support reproducible calculations and processing of greenhouse gas fluxes measured with the static chamber method. The package includes raw data file parsing from widely used IRGAs, metadata matching, unit conversion, flux estimations, and initial quality assurance/quality control (QA/QC). Diagnostic graphical plots provide a transparent way to differentiate between measurement issues and nonlinear behavior. The package is also designed to be easily integrated with the gasfluxes package for further fitting of nonlinear concentration‐time models, allowing alternative or additional flux QA/QC. The fluxfinder package offers a flexible workflow that is easily adaptable to promote open and reproducible greenhouse gas flux estimations.

Magmatic and rock-leaching contributions to the metal load in hydrothermal fluids at þeistareykir, Iceland

Magmatic-hydrothermal systems are key environments to study the transfer of elements from the deep Earth to the surface and the mobilization and re-distribution of elements within the crust. These systems have been recognized as potential active analogue sites for ore deposition. The source of fluids and their metal load is split between the relative contributions from degassing of underlying magma and interactions between the hydrothermal fluid and the host rock. Here, we combine analyses of noble gases and volatile metals in fluids and rocks from the þeistareykir geothermal field (NE Iceland) to provide constraints on the relative contribution of these two sources. Helium isotope data suggest 80–85% originated from magma degassing. The 3He/4He ratio, corrected for atmospheric contamination (Rc/Ra) correlates with volatile metal abundances in surface fluids and indicates that Bi and Hg are predominantly derived from magma degassing. It is also shown that the deep geothermal reservoir fluid is dominated by magmatic input, except for Mn, Fe, Co, Cu, Ti and V, using the elemental signature of magmatic degassing and water-rock interaction. The spatial variations in Rc/Ra and surface fluid volatile metal contents among the wells suggest an impact of the local and regional structures on the fluid's pathway from depth to surface.

Diagnostic approach to rickets: an Endocrine Society of Bengal (ESB) consensus statement.

Rickets, one of the leading causes of bony deformities and short stature, can be calciopenic (inciting event is defective intestinal calcium absorption) or phosphopenic (inciting event is phosphaturia). Early diagnosis and timely treatment of rickets are crucial for correction of the limb deformities. Guidelines exist for nutritional rickets, but the diagnosis and management of the relatively uncommon forms of rickets are complex. This consensus aims to formulate a simplified diagnostic approach for rickets, especially in resource-limited settings. The consensus statement has been formulated by a 29-member committee from the Endocrine Society of Bengal. The process included forming a working group, conducting a literature review, identifying controversies, drafting, and discussion at a consensus meeting. Participants rated their agreement with the clinical practice points, and a 70% consensus was required. Input integration and further review led to the final consensus statements. Children with suspected rickets should initially be examined for distinctive skeletal deformities. The diagnosis of rickets should be confirmed with characteristic radiographic abnormalities. It is advisable to order tests for serum calcium, inorganic phosphorus (Pi), liver function, 25-hydroxyvitamin D (25OHD), parathyroid hormone, creatinine, and potassium in all patients with rickets. In cases of refractory rickets, it is also recommended that assessments be conducted for spot urine calcium, Pi, creatinine, and, blood gas analysis. In children with rickets and metabolic acidosis, tests for glycosuria, uricosuria, aminoaciduria, low molecular weight proteinuria, and albuminuria should be conducted. In children with resistant calciopenic rickets and sufficient serum 25OHD levels, serum 1,25(OH)2D concentration should be tested. 1,25(OH)2 D and fibroblast growth factor 23 estimation is useful for certain forms of phosphopenic rickets.

Addressing Low-Cost Methane Sensor Calibration Shortcomings with Machine Learning

Quantifying methane emissions is essential for meeting near-term climate goals and is typically carried out using methane concentrations measured downwind of the source. One major source of methane that is important to observe and promptly remediate is fugitive emissions from oil and gas production sites but installing methane sensors at the thousands of sites within a production basin is expensive. In recent years, relatively inexpensive metal oxide sensors have been used to measure methane concentrations at production sites. Current methods used to calibrate metal oxide sensors have been shown to have significant shortcomings, resulting in limited confidence in methane concentrations generated by these sensors. To address this, we investigate using machine learning (ML) to generate a model that converts metal oxide sensor output to methane mixing ratios. To generate test data, two metal oxide sensors, TGS2600 and TGS2611, were collocated with a trace methane analyzer downwind of controlled methane releases. Over the duration of the measurements, the trace gas analyzer’s average methane mixing ratio was 2.40 ppm with a maximum of 147.6 ppm. The average calculated methane mixing ratios for the TGS2600 and TGS2611 using the ML algorithm were 2.42 ppm and 2.40 ppm, with maximum values of 117.5 ppm and 106.3 ppm, respectively. A comparison of histograms generated using the analyzer and metal oxide sensors mixing ratios shows overlap coefficients of 0.95 and 0.94 for the TGS2600 and TGS2611, respectively. Overall, our results showed there was a good agreement between the ML-derived metal oxide sensors’ mixing ratios and those generated using the more accurate trace gas analyzer. This suggests that the response of lower-cost sensors calibrated using ML could be used to generate mixing ratios with precision and accuracy comparable to higher priced trace methane analyzers. This would improve confidence in low-cost sensors’ response, reduce the cost of sensor deployment, and allow for timely and accurate tracking of methane emissions.

Enhancing Predictive Maintenance of Power Transformers Through Machine Learning Approaches

This paper focuses on the use of machine learning algorithms to assist in predictive maintenance, aiming to reduce downtime and associated costs for electrical equipment. It introduces two machine learning predictive indicators: the Chromatographic Assay Indicator (CAI) and the Electrical Failure Risk Indicator (EFRI), which leverage chromatographic and sensor data, respectively. The CAI indicator was trained on external data, and its generalization capability was assessed using company-specific chromatographic data with expert assistance. The evaluation involved two heuristics, both focusing on keyword identification in free-text diagnoses. Results showed over 90% accuracy in predicting failures in reactors and power transformers, and an AUC of nearly 85% for reactors. Additionally, CAI outperformed classical Dissolved Gas Analysis (DGA) methods. On the other hand, the EFRI indicator was trained using company’s internal data from a monitoring system of operational sensors and maintaining power transformer data. The classification model achieved over 95% accuracy and an AUC of almost 90% on the test set. These results indicate that both indicators can be integrated into a solution to support maintenance specialists in their decision-making processes.

The identification and correction of pseudohypercalcemia.

We found that a subset of patients with monoclonal gammopathy exhibited hypercalcemia without apparent causes or clinical manifestations In a cohort of 289 monoclonal gammopathy patients, 2.4% presented with such atypical hypercalcemia, with one notable case exhibiting normal ionized calcium levels, suggesting the presence of pseudohypercalcemia. The aim of this study is to elucidate the factors contributing to pseudohypercalcemia in monoclonal gammopathy and to develop a novel globulin-corrected calcium formula for clinical application. This observational study enrolled 110 monoclonal gammopathy patients from our center. An additional 33 patients were recruited to validate the newly proposed formula. Univariate analysis identified potential risk factors. And multivariate logistic regression identified definitive influential factors. The determined influential factors were utilized to develop a formula by multiple linear regression, which was validated by a paired t-test and the Youden index. This study found that globulin was a risk factor for pseudohypercalcemia. It revealed that pseudohypercalcemia should be considered in patients with globulin levels ≥61 g/L (P=0.014). Both albumin and globulin were confirmed as independent factors associated with bound calcium. Given that, we developed a formula to correct ionized calcium levels, which was consistent with ionized calcium tested by blood gas analysis. The diagnostic accuracy of the new formula (Youden index is 0.906) is better than the traditional formula (Youden index is 0.906). Interestingly, all monoclonal immunoglobulin types, except for light chains, showed an equal propensity to develop pseudohypercalcemia (P=0.306). It also showed a linear correlation between IgA, IgG, and IgM and bound calcium. This study confirmed that elevated globulin affects serum total calcium and offered the threshold of globulin ≥ 61 g/L in the differential diagnosis of peudohypercalcemia from hypercalcemia. The new formula based on albumin and globulin was developed, which was verified to be better than the traditional formula for correctly diagnosing hypercalcemia. In addition, we found that neither light chains nor heavy chains of monoclonal immunoglobulin alone can result in pseudohypercalcemia.

The effects of NH3 pre-cracking and initial temperature on the intrinsic instability and NOx emissions of NH3/bio-syngas/air premixed flames

The study of the combustion characteristics of NH₃/bio-syngas/air under NH₃ partial cracking and elevated initial temperatures can enhance its feasibility as a practical fuel. The effects of NH₃ cracking rates (ζ) and initial temperature (T0) on the laminar burning velocity (SL), instability, and NO emissions of NH₃/bio-syngas/air premixed flames under different equivalence ratios are investigated. The results indicate that increasing ζ and T0 enhances the SL of the premixed flame, with ζ having a more pronounced effect on combustion enhancement. Virtual gas analysis reveals that pre-cracking primarily strengthens combustion through chemical effect. An increase in ζ significantly shifts the peak SL towards the fuel-rich region, while at any T0, the peak SL consistently occurs around Φ = 1.1. Increasing ζ and T0 reduces the critical radius (rc) and the critical Peclet number (Pec) of the premixed fuel, with rc decreasing more rapidly when ζ is below 30 %. The dimensionless growth rate (∑) increases with the rise in ζ and T0, consistently remaining positive, indicating an unstable state. Additionally, ∑ varies more significantly with T0 when T0 is below 450 K. When ζ is below 60 %, the NO mole fraction increases with the increase in ζ. However, at ζ = 80 %, the NO mole fraction is lower than at ζ = 40 %. Increasing T0 continually increases the NO mole fraction. Analysis of the NH3 reaction pathways indicates that NHi (i = 0, 1, 2) is closely related to the NO → N2 reduction reactions.

Implementation of Fuzzy Logic Scheme for Assessment of Power Transformer Oil Deterioration Using Imprecise Information

This research aims to analyze the implementation of a fuzzy logic-based approach in improving the diagnosis of power transformer oil deterioration, which is critical for maintaining the efficient performance and operational life of transformers. Traditional diagnoses are based on strict measurements that do not account for the factors of variability and uncertainty of the actual data. In this article, we perform six different types of tests in this regard, and data have been collected during the period of 2021 to 2022 of 188 power transformer failures in the New KotLakhpat Lahore unit, whose voltage range is 132/66 kv and rating capacity is 40/50 MVA. In this case, a fuzzy logic-based scheme is developed based upon the membership function, a rule-based and defuzzification method that works with imprecision and the implementation of uncertainty in assessing the condition of transformer oils. Moisture, acidity, and a dissolved gas analysis indicator, along with other indication approaches such as interfacial tension, viscosity, and tangent delta measurement, are used to analyze the deterioration process in transformer oils. In the visual representation, oil samples with the following properties were first fuzzified: 19.9 mm2/s of viscosity, 0.453 mgKOH/g of acidity, 695 ppm of DGA, 20.8 mg/kg of moisture, 19.98 of IFT, and 4.35 × 100.14 of tangent delta. The output that was generated by software using the values entered into the parameters (HI and Age) after defuzzification is 45. Fuzzy logic serves as a concrete framework for transforming the diagnostics system and deterring the threats to the entire transformer’s health and reliability in the future. By using this technique, various faults were hypothetically and practically analyzed in a transformer to implement early detection technologies with the possibility to reduce maintenance costs and extend operational life up to 45 years. Various case studies indicate the effectiveness of fuzzy logic in comparison to traditional diagnostics.

Distribution of air quality data across stratified areas of Port Harcourt metropolis

Distribution of Air Quality Data across seven stratified areas of Port Harcourt Metropolis was carried out. The study utilized a total of 18 parameters from four different air quality datasets obtained from 24 sampling points during field data collection. The sampling points were structured and stratified into residential, industrial, commercial, recreational, transport, dumpsite and abattoir areas. Air quality data were acquired using a multi-digital potable tool, Aerosol Gas Monitor and TESTO Gas Analyser for meteorological data, particulate matters (PM), gaseous emissions and heavy metals. Results showed that the concentrations of air quality data were not evenly distributed across the seven stratified areas, an indication of the influence of location-based activities on the distribution of air quality parameters. The minimum and maximum values of wind speed, temperature and relative humidity were obtained within Residential and Transport Areas, Abattoir and Dumpsite Areas, and, Industrial and Recreational Areas with numerical values of 1.1ms-1 and 3.7ms-1, 27.20C and 350C, and, 67.8% and 923% for wind speed, temperature and relative humidity respectively. The values of TSP, PM2.5 and PM10 ranged from 53 to 255 μg/m3, 13 to 90 μg/m3 and 40 to 169μg/m3 for TSP, PM2.5 and PM10 respectively with the lowest and highest values obtained within Residential and Dumpsite Areas respectively. The concentrations of NO2 and SO2 exceeded the standards of WHO, NAAQS and FMEnv in Industrial, Dumpsite and Abattoir Areas. Lead ( Pb) showed very high values within Dumpsite Area (0.954mg/kg), Industrial Area (0.372mg/kg) and Transport Area (0.077mg/kg).

Severe Respiratory Acidosis in Acute Exacerbation COPD, Is that Possible to Treat?

Introduction: Chronic obstructive pulmonary disease (COPD), currently the third leading cause of death worldwide, is a common condition characterized by progressive airflow limitation and tissue destruction. Patients with COPD may present to the Emergency Room (ER) with severe acute exacerbations (AECOPD), which can be associated with acute respiratory failure—a life-threatening condition with a mortality rate approaching 50% in Indonesia—requiring rapid intervention and ICU admission. In this report, we present a severe respiratory acidosis in AECOPD case with successful emergency followed by ICU management and the frequent pitfalls. Case Illustration: In this report we present a-67 years old male, pedicab driver and smoker came to the ER with acute onset shortness of breath and decrease of consciousness with history of shortness of breath in last 10 years. In primary survey we found clear wheezing sound, tachypnea, intercostal retraction, decrease of peripheral oxygen saturation, tachycardia and verbal respond of consciousness. Blood gas analysis result interpreted severe respiratory acidosis with pH 6.90 and pCO2 128.5 mmHg. Chest radiograph showed infiltrate that became the cause of exacerbation. Endotracheal intubation was performed due to decreased consciousness, persistent tachypnea and pCO2 over 100 mmHg. This patient was hospitalized for 12 days including 9 days in ICU followed by 3 days in regular ward. Conclusion: The goal for AECOPD management is to minimize and prevent the negative effects of the exacerbation.

Clinical evaluation of serum miR-513a-3p combined with arterial blood gas analysis parameters and lung ultrasound score in neonatal respiratory distress syndrome

BackgroundNeonatal respiratory distress syndrome (NRDS) is harmful to neonates and the prognosis is variable, ranging from mild to severe forms. This study aims to evaluate the clinical utility of miR-513a-3p in conjunction with arterial blood gas analysis parameters and lung ultrasound (LUS) score in the context of NRDS.MethodsThe study included 169 preterm infants, including 106 newborns with NRDS and 63 newborns without NRDS. The relative expression level of miR-513a-3p was detected by quantitative real time polymerase chain reaction (qRT-PCR). Umbilical artery blood gas parameter values and LUS score were recorded, and the clinical significance of miR-513a-3p, umbilical artery blood gas parameter and LUS score in NRDS were evaluated by Receiver Operating Characteristic (ROC) analysis.ResultsElevated levels of miR-513a-3p were detected in the serum of NRDS, and higher expression of miR-513a-3p was observed in individuals with poor prognosis. Notably, miR-513a-3p exhibited a significant correlation with the parameters of arterial blood gas analysis and LUS score in NRDS patients. Furthermore, miR-513a-3p was one of the risk factors for poor prognosis in NRDS patients. miR-513a-3p levels combined with umbilical artery blood gas parameters and LUS score has diagnostic value for NRDS and is reliable for its prognosis.ConclusionsElevated levels of miR-513a-3p in neonatal serum served as a useful tool in the combined assessment with umbilical artery blood gas analysis and LUS score to diagnosis and prognosis of NRDS. Consequently, miR-513a-3p may be served as a biomarker for diagnosis and prognosis of NRDS.

Calcium propionate is an alkalizing agent in exercising Standardbreds

The objective of this study was to determine if calcium propionate is an alkalizing agent in exercising Standardbreds and if it alters plasma glucose and serum insulin concentrations. This study used a randomized crossover design to test the hypotheses that calcium propionate alters total CO2 (tCO2), Ca++, pH, strong ion difference (SID), glucose, and insulin in Standardbreds completing a simulated race test (SRT) on a high-speed equine treadmill. Blood was collected from eight horses (mean age ± SD = 16 ± 2.7 years; range = 13 - 21 years) at 10 and 5 min prior to treatment or control administration, just prior to the subsequent SRT, directly after the SRT, and at 60- and 90-min post SRT. Plasma pH and plasma concentrations of tCO2, glucose, Ca++, and Na+, K+, Cl-, Lac- (for SID calculation) were measured in duplicate by blood gas analyzer and serum insulin by radioimmunoassay. Data were analyzed by two-way repeated-measures ANOVA. For plasma pH, Na+, K+, Cl-, Lac-, SID, insulin and glucose, no effects of treatment or treatment by sampling-timepoint interaction were found (p>0.05). Plasma tCO2, Ca++, pH, Na+, SID, and glucose concentrations were significantly lower, and Lac- was significantly higher, directly after the SRT compared to all other timepoints (p<0.05). Plasma tCO2, HCO3- and Ca++ were significantly higher in treated than in control horses at multiple sampling timepoints after treatment/control administration (p<0.05). Serum insulin concentration, measured only pre and 30 min post treatment/control administration, was unaffected by treatment. Calcium propionate is an alkalizing agent in horses.

Evidence that mitral and/or tricuspid regurgitation diminishes stroke volume increase during exercise

Abstract Background and Purpose The severity of heart failure can be evaluated by peak oxygen consumption (VO2). Cardiac output is one of the major essential factors to determine the VO2. Therefore, cardiac output increases linearly as the exercise intensity increases. However, in mitral regurgitation, effective stroke volume decreases due to some blood flowing back into the left atrium from the left ventricle. This reduction may compromise oxygen delivery to working muscles and diminish oxygen uptake. Peak VO2/HR is known to indicate the stroke volume at the peak exercise, but since c(A-V)O2 difference shows almost a similar change pattern during a ramp protocol, VO2/HR during the load is also reported to be an indicator of stroke volume (SV) at that work rate. However, there are no investigations that have examined the extent to which the increase in cardiac output during stress is affected by the severity of mitral regurgitation. Therefore, we investigated the influence of the degree of regurgitant volume in mitral regurgitation (MR) and tricuspid regurgitation (TR) affects the SV increasing response to exercise load. Additionally, we examined whether blunted SV increase influences on the peak VO2. Methods Among 525 patients who underwent cardiopulmonary exercise test (CPX) at our institution from January 2023 to October 2023, 518 patients (143 females, 375 males, mean age 65.2±15.0 years old) where precise analyses of CPX was possible. CPX was performed using breath-by-breath gas analysis, and an incremental load test (10watts/min) was administered until exhaustion. The rate of increase in VO2/HR per watt during an incremental loading (Δ(VO2/HR)/ΔWR) was used as an indicator of the degree of increase in SV. Typically, SV increases up to 60% of maximum load, around AT, after which it stops increasing and plateaus. Therefore, the slope of Δ(VO2/HR)/ΔWR was examined from the initiation of ramp loading to AT. The degree of reflux was evaluated by echocardiography and classified as none/trivial, mild and moderate/severe. The number of people in each group of None/trivial, mild, moderate/severe was, 392, 83, 30 for MR, and 416, 64, 24 for TR. Δ(VO2/HR)/ΔWR was evaluated for each degree of reflux, using ANOVA to determine whether there was a difference between groups. Results As shown in the Figure1, Δ(VO2/HR)/ΔWR decreased as the reflux flow rate increased for both MR and TR. Concurrently, peak VO2 also decreased in the moderate/severe group compared to the non/trivial-reflux group for both MR and TR (MR: 17.5±5.4 mL/min/kg vs. 14.9±3.5 mL/min/kg, TR: 17.2±5.3 mL/min/kg vs. 13.6±3.8 mL/min/kg). Conclusion The Δ(VO2/HR)/ΔWR obtained through CPX has been shown to be an index that can evaluate the severity of reflux. Additionally, it was also demonstrated that as regurgitation flow increased, true stroke volume decreases, which is correlated with a reduction in peak VO2.

Obesity and its impact on functional capacity: understanding the interplay for health management

Abstract Background Cardiopulmonary exercise testing (CPET) plays a significant role in evaluating obese individuals due to the unique physiological challenges they face during exercise. As diastolic function is impaired in majority of morbidly obese pts, combination of CPET with diastolic stress echocardiography may add more information to objective assessment Objective To assess the value of combined stress echo CPET (ESE-CPET) in assessment of diastolic function in morbidly obese pts. Methods We studied 400 pts (74% female, age 39.2±9.9 years) referred for bariatric surgery. Echocardiographic measurements have been performed before CPET and immediately after the test. CPET was performed on treadmill (maximal Bruce) with breath-by-breath gas analysis. We measured both peak oxygen consumption (peakVO2) and VO2 at anaerobic threshold (AT), as well as other ventilatory and hemodynamic parameters. Results Mean BMI was 44± kg/m2. Left ventricular ejection fraction was 63.5±5.6%. Mean VO2 at AT was 17±2 ml/kg/min, mean Peak VO2 was 19±4 ml/kg/min. Resting eho : mitral E to A wave (E/A),deceleration time ( Dt) and mitral E to mitral anular E’ (E/E’) values did not correlate significantly with parameters of CPET. However, there was significant correlation between maximal E/ E’ with PeakVO2 and VO2 at AT (p&amp;lt;0.001), , Pet CO2 (p=0.0001) as well as with myocardial performance index as a parameter of global left ventricular function (p&amp;lt;0.001) However, VE/VCO2 was the strongest predictor of increase in E/ E’≥ 15 indicating the importance of ventilatory parameters and dynamic tests. Conclusions Assessment of diastolic function in morbid obese patients represents a great challenge to cardiologists because obesity contributed significantly to deterioration of diastolic function. Combined stress echo CPET showed the advantage and benefit of integrated evaluation of both pulmonary and cardiovascular function representing as a significant step forward in assessment of diastolic function overcoming the limitations of resting echocardiography and CPET performed as a single test.

Brazilian natural gas market dynamics: A data panel analysis of the Brazilian market compared with Argentina, Colombia, Mexico, and India using Porter's five forces framework

This study offers a comparative analysis of natural gas markets in Brazil, Mexico, Colombia, Argentina, and India, spanning from 2000 to 2020. Leveraging panel data and historical time series analysis, coupled with Porter's Five Forces framework, it examines industry dynamics across upstream, downstream, midstream, and upstream dimensions. Insights into competitive landscapes are derived, considering regulatory frameworks, resource availability, infrastructure development, and demand patterns. Despite Brazil's efforts to enhance domestic production, infrastructure, and regulatory reforms, challenges persist, hindering sectoral growth. Comparative studies underscore the need for policy improvements to align with investment commitments. This study contributes novel insights into the competitive positioning of natural gas markets, offering actionable recommendations for stakeholders. Identifying potential bottlenecks informs strict decision-making in the global energy landscape.

Adsorption Properties of Metal Atom (Co, V, W, Zr)-Modified MoTe2 for CO, CH3CHO, and C6H6 Gases: A DFT Study.

This study investigates the adsorption characteristics of the pristine MoTe2 monolayer and the metal atom (Co, V, W, Zr)-modified MoTe2 monolayer on the hazardous gases CO, CH3CHO, and C6H6 based on the density functional theory. The adsorption mechanism was studied from the perspectives of molecular density differences, band structures, molecular orbitals, and the density of states. Research analysis showed that the changes in conductivity caused by the adsorption of different gases on the substrate were significantly different, which can be used to prepare gas sensing materials with selective sensitivity for CO, CH3CHO, and C6H6. This study lays a reliable theoretical foundation for the gas sensing analysis of toxic and hazardous gases using metal atom-modified MoTe2 materials.