Carbon Dioxide Production Research Articles

Habituation Does Not Change Running Economy in Advanced Footwear Technology.

This study aimed to compare running economy across habituated and nonhabituated advanced footwear technology (AFT) in trained long-distance runners. A total of 16 participants completed up to six 5-minute trials in 1 to 3 pairs of their own habituated shoes and 3 different and standardized AFTs at individual marathon pace. We measured oxygen uptake and carbon dioxide production and expressed running economy as oxygen uptake (in milliliters oxygen per kilogram per minute), oxygen cost of transport (oxygen per kilogram per minute), energetic cost (in watts per kilogram), and energetic cost of transport (in joules per kilogram per kilometer). We used linear mixed-effect models to evaluate differences. Relative shoe weight and shoe mileage (distance worn during running) were covariates. Forty-eight standardized and 29 individual AFT conditions were measured (mileage 117.0 [128.8]km, range 0-522km; 25 habituated 135.7 [129.2]km, range 20-522km; 4 nonhabituated 0 [0]km, range 0-0km). Rating of perceived exertion, blood [La], and respiratory exchange ratio ranged from 9 to 15, 1.11 to 4.54mmol/L, and 0.76 to 1.01. There was no effect for habituation on energetic cost of transport (thabituation = -.232, P = .409, b = -0.006; 95% CI, -0.058 to 0.046) or other running economy metrics. Neither shoe weight nor shoe mileage had an effect. Our results suggest that habituation to AFTs does not result in greater benefits in the use of AFTs. This means that implementation in training may not be needed, even if we cannot rule out any other possible benefits of habituation at this stage, such as adaptation of the musculoskeletal system.

The ventilatory efficiency parameters outperform peak oxygen consumption in monitoring the therapy effects on the right ventricular load in patients with hypertrophic cardiomyopathy

Abstract Aim We sought the cardiopulmonary exercise testing (CPET) parameter that is the most reflective of right ventricular (RV) load and its coupling with pulmonary artery (PA) in patients diagnosed with hypertrophic cardiomyopathy (HCM) undergoing medical therapy. Methods CPET on recumbent bike was performed in adult patients with symptomatic non-obstructive HCM with NYHA class I–III, during phase II, randomised, open-label multicentre study, before and after diverse medical treatment for 16 weeks. Endpoints were the changes in: 1) peak oxygen consumption (peak VO2); 2) minute ventilation (VE)/carbon-dioxide (CO2) production slope during the whole CPET; 3) VE/VCO2 slope before anaerobic threshold (AT); 4) VE/VCO2 slope after AT; 5) VE/VCO2 nadir; 6) VE/VCO2 at AT; and 7) VE/VCO2 intercept. Standard ehocardiography at rest was performed concomitantly with CPET to assess tricuspid annular plane systolic excursion (TAPSE), pulmonary artery systolic pressure (PASP), severity of mitral regurgitation (MR) and TAPSE/PASP ratio as a measure of RV-PA coupling. Results Of 115 screened patients, 61 (mean age 52 years [SD 14], 43% women) met the study inclusion criteria and underwent CPET. On regression analysis, among all CPET end-point variables, the best independent predictor of the change in PASP, TAPSE and MR severity after 16 weeks of medical treatment was VE/VCO2 below AT (B=-0.28, -0.01,-0.11; SE=0.10, 0.05, 0.01; CI=-0.48 to -0.08, -0.22 to -0.01; -0.02 to 0.01; p=0.007, 0.035, 0.004, respectively), whereas the best predictor of TAPSE/PASP ratio was intercept of the VE/VCO2 curve (B=0.014, CI=0.01to 0.03, p=0.005). Conclusion The changes in VE/VCO2 slope below anaerobic threshold, and intercept of the VE/VCO2 curve outperform peak VO2 in the monitoring of therapy effects on the right heart load and RV-PV coupling in patients with hypertrophic cardiomyopathy.

Exercise oscillatory ventilation as a predictor of mortality in patients with amyloid cardiomyopathy

Abstract Background Exercise oscillatory ventilation (EOV) signals multiple abnormalities in hemodynamics and ventilatory control which may predict poor outcome in patients with cardiac diseases. Purpose To assess whether EOV (+) patients with amyloid cardiomyopathy show higher mortality rates compared to their counterparts without EOV. Methods We analyzed cardiopulmonary exercise testing results for EOV defined by continuous (>60% of exercise duration) oscillations in minute ventilation (VE), cycling with a frequency of one minute and an amplitude above 15% of resting VE, in patients with amyloid cardiomyopathy. Results 156 patients with amyloid cardiomyopathy, aged 78 (±7) years, 87% male with a NYHA functional class of II (49.4%) and median B-type natriuretic peptide levels of 2548 (1374-4703) ng/L. Comorbidities include hypertension (73.1%), polyneuropathy (45.5%), coronary heart disease (41.0%), diabetes mellitus (17.3%) and chronic obstructive pulmonary disease (10.9%). Patients had a mean peak oxygen consumption of 14.8 (±4.42) ml/kg·min and a VE to carbon dioxide production (VCO2) slope ≥ 40 in 67.9% of cases. EOV was seen in 38 (24.4%), clearly absent in 92 (59.0%) and not clearly differentiable in 26 (16.7%) patients. 33 (21.2%) had a HF-related hospitalization and 31 (19.9%) died. EOV shows a hazard ratio of 2.35 (CI 1.088 – 5.075, p-value <0.05) for all-cause mortality. In fact, the log-rank test showed a difference in survival time between patients with and without EOV (p=0.03) with a median survival time of 46 months. Conclusion EOV may improve the prognostic yield of incremental CPET in patients with amyloid cardiomyopathy.Kaplan-Meier Curve for EOV

Relationship between six-minute walk distance and cardiopulmonary exercise testing in non-obstructive hypertrophic cardiomyopathy

Abstract Background Recent studies have shown the promise of new approaches to the management of hypertrophic cardiomyopathy (HCM) symptoms. However, as HCM is a chronic disorder that evolves slowly over decades with low annual event rates, therapeutic trials in the disease rely on surrogate measures of disease severity and progression rather than hard endpoints such as mortality. Exercise capacity is one potential surrogate endpoint. Purpose To examine the relationship between peak oxygen uptake (VO2) and six-minute walk test distance (6MWD) in patients with non-obstructive hypertrophic cardiomyopathy (nHCM) and describe the association with clinical parameters and quality of life. Methods We examined baseline data from patients with nHCM enrolled in a randomised placebo-controlled trial of trimetazidine therapy. The study was conducted in a single European centre. Cardiopulmonary exercise testing (CPET) was performed to assess peak oxygen consumption (pVO2), ventilatory anaerobic threshold (VAT) and ventilatory equivalent for carbon dioxide (minute ventilation to carbon dioxide production (VEVCO2). Health related quality of life was assessed with the Minnesota Living with Heart Failure Questionnaire (MLHFQ). ECG and echocardiography were performed on the same day and biomarkers (NT-proBNP and cardiac Troponin T, cTnT) were measured prior to exercise testing. Results In 51 patients (age 50 ± 13 years; 71% male) with nHCM, pVO2 ranged from 10 to 24.3 ml/kg/min and 6MWD from 188 to 650 metres. 6MWD correlated with peak VO2 (Pearson r=0.41, 95% CI 0.15 to 0.67, p=0.003) and anaerobic threshold (r=0.32, 95%CI 0.04 to 0.55, p=0.024). After adjusting for age and sex, NT-proBNP concentration correlated with peak VO2 (radi=-0.35, 95% CI -0.69 to -0.01, p=0.042) but not 6MWD (radj=-0.05, 95% CI -0.42 to 0.32, p=0.779). Health related quality of life assessed by the Minnesota Living with Heart Failure Questionnaire (MLHFQ) correlated moderately with 6MWD (radi=-0.54, 95% CI -0.79 to -0.29, p<0.001) but weakly with peak VO2 (radi 0.28, 95% CI -0.55 to -0.01, p=0.042). I Conclusions There is a modest correlation between peak VO2 and 6MWD in nHCM. The pVO2 correlates more strongly with NT-proBNP whereas 6MWD better reflects quality of life. These data suggest pVO2 and 6MWD provide complementary information about health status in nHCM.Relationship between 6MWD and CPETCharacteristics of study cohort

Integrated study of hydraulic/CO2 fracturing and production coupled with a THM-D process in ultra-shallow shale reservoirs

To explore fracturing technology for vertical wells in ultra-shallow shale gas reservoirs, a coupled thermo-hydro-mechanical-damage (THM-D) fracturing and production integration model is established in this study. In addition, a new coupled hydro-mechanical damage model is established to calculate fracture evolution. These two models are validated through theoretical models and field data, respectively. Based on these models, the quality of fracturing under different geological parameters, fracturing parameters, and fracturing technology is compared and analyzed. The results show that the distribution of natural fractures significantly influences fracturing and production. In addition, due to the high leak-off in the ultra-shallow shale reservoir, the total fracture length and cumulative production after 720 days of carbon dioxide fracturing are only 70.35% and 77.26% of the values achieved by hydraulic fracturing, respectively. Therefore, it is necessary to consider reducing carbon dioxide leak-off in the design of carbon dioxide fracturing in ultra-shallow shale reservoirs. Fracturing efficiency also should be considered when designing fracturing time. When the injection rate is 5 m3/min, the efficiency drops sharply if the fracturing time exceeds 67.45 min. The production of hydraulic fracturing and carbon dioxide fractured wells has also been studied when fracturing methods without proppant are used. This study found that a satisfactory production rate can also be achieved in ultra-shallow shale gas reservoirs when fracturing without proppant.

Deciphering the complex interplay: Heterogeneous, threshold, and mediation effects of trade openness on CO2 emissions in Africa.

Despite having barely anything to do with the issue of CO2 emissions, Africa has been experiencing more severe climate change and its adverse effects than most other regions of the globe. However, the issue of CO2 emissions and its adverse effects has received relatively little attention in the African research arena. To this end, the present research assesses the effect of trade openness on the CO2 emissions utilizing panel data from 46 African countries spanning 2000 through 2022. To account for the possible heterogeneity and nonlinearity, the panel quantile regression and threshold methods were employed. Moreover, this study investigates the key mediating effects of the channel. The empirical findings show that greater trade openness is associated with significantly higher CO2 emission, additionally; it demonstrates that the influence is heterogeneous across different CO2 emission quantiles in African countries. Besides the result from the double threshold model reveals a complex, nonlinear relationship between trade openness and CO2 emissions in Africa. Moreover, the findings divulge that openness to trade indirectly reduces CO2 emissions through the substitution and technology channels whereas it indirectly increases carbon dioxide production via the economic track. Therefore, it is vital to promote the use of renewable energy, effectively leverage the knowledge spillover effects of trade to decrease energy intensity and formulate pertinent policies aimed at curbing carbon emissions and addressing the imminent threat of climate change in Africa. Besides, the nonlinear and heterogeneous effects of trade openness on CO2 emissions suggest that policies and interventions related to the impact of trade openness on CO2 emissions should consider the current level of carbon dioxide emissions.

Structural and functional insights from the sequences and complex domain architecture of adhesin-like proteins from Methanobrevibacter smithii and Methanosphaera stadtmanae

Methanogenic archaea, or methanogens, are crucial in guts and rumens, consuming hydrogen, carbon dioxide, and other fermentation products. While their molecular interactions with other microorganisms are not fully understood, genomic sequences provide information. The first genome sequences of human gut methanogens, Methanosphaera stadtmanae and Methanobrevibacter smithii, revealed genes encoding adhesin-like proteins (ALPs). These proteins were also found in other gut and rumen methanogens, but their characteristics and functions remain largely unknown. This study analyzes the ALP repertoire of M. stadtmanae and M. smithii using AI-guided protein structure predictions of unique ALP domains. Both genomes encode more than 40 ALPs each, comprising over 10% of their genomes. ALPs contain repetitive sequences, many of which are unmatched in protein domain databases. We present unique sequence signatures of conserved ABD repeats in ALPs and propose a classification based on domain architecture. Our study offers insights into ALP features and how methanogens may interact with other microorganisms.

Anaerobic Degradation of Aromatic and Aliphatic Biodegradable Plastics: Potential Mechanisms and Pathways.

Biodegradable plastics (BDPs) have been widely used as substitutes for traditional plastics, and their environmental fate is a subject of intense research interest. Compared with the aerobic degradation of BDPs, their biodegradability under anaerobic conditions in environmental engineering systems remains poorly understood. This study aimed to investigate the degradability of BDPs composed of poly(butylene adipate-co-terephthalate) (PBAT), poly(lactide acid) (PLA), and their blends, and explore the mechanism underlying their microbial degradation under conditions of anaerobic digestion (AD). The BDPs readily depolymerized under thermophilic conditions but were hydrolyzed at a slow rate under conditions of mesophilic AD. After 45 days of thermophilic AD, a decrease in the molecular weight and significant increase in the production of methane and carbon dioxide production were observed. Network and metagenomics analyses identified AD as reservoirs of plastic-degrading bacteria that produce multiple plastic-degrading enzymes. PETase was identified as the most abundant plastic-degrading enzyme. A potential pathway for the anaerobic biodegradation of BDPs was proposed herein. The polymers of high molecular weight were subjected to abiotic hydrolysis to form oligomers and monomers, enabling subsequent microbial hydrolysis and acetogenesis. Ultimately, complete degradation was achieved predominantly via the pathway involved in the conversion of acetic acid to methane. These findings provide novel insight into the mechanism underlying the anaerobic degradation of BDPs and the microbial resources crucial for the efficient degradation of BDPs.

Pressure Swing Adsorption Configurations for Simultaneous Production of High-Purity Biomethane and Carbon Dioxide from Biogas

Pressure Swing Adsorption Configurations for Simultaneous Production of High-Purity Biomethane and Carbon Dioxide from Biogas

Impairment of Cardiovascular Functional Capacity in Mild to Moderate Kidney Dysfunction.

Traditional diagnostic tools that assess resting cardiac function and structure fail to accurately reflect cardiovascular alterations in patients with chronic kidney disease (CKD). This study sought to determine whether multidimensional exercise response patterns related to cardiovascular functional capacity can detect abnormalities in mild-to-moderate CKD. In a cross-sectional study, we examined 3,075 participants from the Framingham Heart Study (FHS) and 451 participants from the Massachusetts General Hospital Exercise Study (MGH-ExS) who underwent cardiopulmonary exercise testing (CPET). Participants were stratified by estimated glomerular filtration rate (eGFR): eGFR ≥90; eGFR 60-89; eGFR 30-59. Our primary outcomes of interest were peak oxygen uptake (VO 2 Peak),VO 2 at anaerobic threshold (VO 2 AT), and the ratio of minute ventilation to carbon dioxide production (VE/VCO 2 ). Multiple linear regression models were fitted to evaluate the associations between eGFR group and each outcome variable adjusted for covariates. In the FHS cohort, N=1,712 (56%) had an eGFR ≥90 ml/min/1.73m 2 , N=1,271 (41%) had an eGFR 60-89 ml/min/1.73m 2 , and N=92 (3%) had an eGFR 30-59 ml/min/1.73m 2 . In the MGH-ExS cohort, N=247 (55%) had an eGFR ≥90 ml/min/1.73m 2 , N=154 (34%) had an eGFR 60-89 ml/min/1.73m 2 , and N=50 (11%) had an eGFR 30-59 ml/min/1.73m 2 . In FHS, VO 2 Peak and VO 2 AT were incrementally impaired with declining kidney function ( p <0.001); however this pattern was attenuated following adjustment for age. Percent-predicted VO 2 Peak at AT was higher in the lower eGFR groups ( p <0.001). In MGH-ExS, VO 2 Peak and VO 2 AT were incrementally impaired with declining kidney function in unadjusted and adjusted models ( p <0.05). VO 2 Peak was associated with eGFR ( p <0.05) in all models even after adjusting for age. On further mechanistic analysis, we directly measured cardiac output (CO) at peak exercise via right heart catheterization and found impaired CO in the lower eGFR groups ( p ≤0.007). CPET-derived indices may detect impairment in cardiovascular functional capacity and track cardiac output declines in mild to moderate CKD.

New Insights into the Understanding of High-Pressure Air Injection (HPAI): The Role of the Different Chemical Reactions

High-pressure air injection (HPAI) is an enhanced oil recovery process in which compressed air is injected into deep, light oil reservoirs, with the expectation that the oxygen in the injected air will react with a fraction of the reservoir oil at an elevated temperature to produce carbon dioxide. The different chemical reactions taking place can be grouped into oxygen addition, thermal cracking, oxygen-induced cracking, and bond scission reactions. The latter reactions involve the combustion of a flammable vapor as well as the combustion of solid fuel, commonly known as “coke”. Since stable peak temperatures observed during HPAI experiments are typically below 300 °C, it has been suggested that thermal cracking and combustion of solid fuel may not be important reaction mechanisms for the process. The objective of this work is to assess the validity of that hypothesis. Therefore, this study makes use of different oxidation and combustion HPAI experiments, which were performed on two different light oil reservoir samples. Modeling of those tests indicate that thermal cracking is not an important reaction mechanism during HPAI and can potentially be ignored. The work also suggests that the main fuel consumed by the process is a flammable vapor generated by the chemical reactions. This represents a shift from the original in situ combustion paradigm, which is based on the combustion of coke.

Off-grid PV/biomass/DG/battery hybrid renewable energy as a source of electricity for a farm facility

Reliable, cost-effective energy systems are pivotal for sustainable development in the agricultural sector. Using the energy balance analysis of the Hybrid Optimization Model for Electric Renewable (HOMER), this study presents a techno-economic assessment of a hybrid renewable energy system for a farm facility. The energy system components considered in the analysis include solar photovoltaics, wind turbines, diesel generators, biomass, and battery storage. The results shows that ten feasible energy systems can technically power the typical farm facility, with a PV-Biomass-DG battery being the best in terms of the total net present cost. The PV-Biomass-DG-battery systems consist of 561.023 kW of PV, 88 kW of diesel generator, 10 kW of biomass, 81 kW of converter, and 584 batteries operated in a load-following mode. When the cost of energy (COE) of EA1 0.206325 $/kWh is compared to EA7 0.407681 $/kWh, a difference of $0.201356 will be saved for every kWh. Also, a comparison of the operating cost of EA1, $65,713.23 and the operating cost of EA7 $212,027.4 showed a margin of $146,314.17 being saved. Energy systems EA3 and EA4 had the lowest carbon dioxide production levels of 15.8 kg annually, respectively. The simple payback period metrics increased from EA1 to EA6 between 2.97 years to 6.99 years. The result of the study shows that adopting a low-carbon energy transition is technically and economically viable for the agricultural sector, especially in developing countries.

No evidence of improvements in energy metabolism after 1week of nitrate and citrulline co-supplementation in elite rowers.

Citrulline (CIT) and beetroot extract (BR) supplements positively impacts exercise performance in elite rowers. However, its influence on metabolic outcomes such as whole-body volumes of oxygen consumption (VO2) and carbon dioxide production (VCO2), substrate oxidation, energy expenditure (EE), and gross efficiency remains unknown. We studied the effects of 1week of daily co-supplementation of 3.5g BR (500mg NO3-) plus 6g CIT on VO2 and VCO2 kinetics, substrate utilization, EE, and gross efficiency in elite male rowers compared to a placebo and to a BR supplementation. Twenty elite rowers participated in this randomized, double-blind, placebo-controlled crossover trial completing 1week of supplementation in each group of study: Placebo (PLAG); BRG; and BR-CITG. Efficiency (70% VO2max) and performance (incremental maximal) tests were performed, and gas-exchange data were collected via indirect calorimetry. Analysis of covariance (ANCOVA) showed no mean between-condition differences on respiratory exchange ratio (RER), EE, and gross efficiency in the efficiency test (all P > 0.06), and in the performance test (all P > 0.28). Moreover, in both tests no interaction Time × Supplement effects were observed for VO2, VCO2, RER, EE, substrate oxidation, and, gross efficiency (all P > 0.12). After 1week, no effects on energy metabolism and substrate utilization were observed after the daily co-ingestion of BR extract plus CIT supplement, therefore longer (> 7days) and higher doses of supplementation might be needed to influence metabolism.

Gamma radiation induced tailoring the structural, optical, surface and mechanical properties of UHMWPE

The present investigation examined how the resultant gamma radiation affected the ultra-high molecular weight polyethylene's (UHMWPE) mechanical, optical, surface, and structural characteristics. Different gamma doses of 75, 150, 250, and 350 kGy were applied to the UHMWPE samples. The study of physical and chemical qualities has involved a variety of spectroscopy techniques, including Fourier Transform Infrared spectroscopy, X-ray diffraction, mechanical property changes, and biocompatibility properties. New bands are formed, as indicated by FT-IR analysis, and this process is linked to the oxidation of irradiation polymer chains and the production of carbon dioxide. The crystallinity of irradiated samples increases as the gamma radiation increases, according to XRD patterns. The analyzed optical results exhibit improvements in the optical characteristics of the irradiated samples. The absorbance spectra of the irradiated samples showed a shift toward the high of wavelength values in the absorption edge as compared to the pristine sample. On the other hand, the optical absorption edge has an increasing tendency as the dose of gamma-ray radiation is increased. As the gamma-ray dose increases, the absorption edge moves toward the longer wavelength. The measurements of the contact angle indicate that the surface free energy rises with increasing gamma irradiation. It was detailed how the mechanical properties of the irradiated UHMWPE samples were measured. The mechanical measurements indicate that the mechanical properties are dose-dependent to some extent. Furthermore, as gamma doses rise, so does the hardness of irradiated UHMWPE.

Evidence for SARS-CoV-2 infected Golden Syrian hamsters (Mesocricetus auratus) reducing daily energy expenditure and body core temperature

Golden Syrian hamsters (Mesocricetus auratus) are a well-established animal model for human infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) due to their susceptibility to SARS-CoV-2 infection, robust virus replication and pathological manifestations similar to human COVID-19 pneumonia. To investigate the physiological changes upon infection in this animal model, we explored the alterations in daily energy expenditure (DEE), water turnover, body mass, body temperature, and locomotor activity in non-infected and SARS-CoV-2 infected Golden Syrian hamsters for four days post SARS-CoV-2. DEE was measured using the doubly labelled water method, which allows for the accurate estimation of carbon dioxide production and, consequently, energy expenditure in animals. Additionally, we investigated total water intake (TWI), which comprises drinking water, preformed water in food, and metabolic water. Using intraperitoneally implanted data loggers, we also monitored body core temperature and locomotor activity in some of the animals. Here we provide evidence for infected hamsters exhibiting significantly lower DEE and TWI compared to non-infected animals. We also observed an increase in body weight in the non-infected animals, while infected animals experienced weight loss. Further, infected animals showed a significantly decreased body temperature, indicating a generally lowered metabolic rate.

Respiratory Muscle Strength as a Predictor of VO2max and Aerobic Endurance in Competitive Athletes

This study explores the association of respiratory muscle strength with aerobic endurance kinetics among athletes, with a specific focus on maximal oxygen consumption (VO2max). Previous research has elucidated the complex interactions between respiratory and skeletal muscles during exercise, highlighting the critical role of efficient respiration in maximizing athletic performance. The interplay between active skeletal muscles and respiratory muscles, especially the influence of respiratory muscle fatigue on exercise capacity, is well-documented. High-intensity exercise has been shown to activate the respiratory muscle metaboreflex, which can restrict blood flow to working muscles, thereby impacting the energy required for respiration. A total of 41 athletes, drawn from the disciplines of biathlon, judo, and cross-country, participated in this study. Respiratory function tests (RFTs) were administered to assess various respiratory parameters, including changes in chest circumference. Additionally, maximal oxygen consumption (VO2max) and heart rate were measured during a treadmill test. To explore the associations between VO2max and ventilatory parameters—namely, ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2)—as well as respiratory metrics, linear regression analysis was employed. Based on the standardized regression coefficients (β), it was found that maximum expiratory pressure (MEP) (mean ± SD: 130.95 ± 42.82) and inspiratory diaphragmatic circumference values were significantly associated with VE, VO2, and VCO2. Conversely, the other predictor variables did not exhibit a significant effect on VE (mean ± SD: 134.80 ± 36.69), VO2 (mean ± SD: 3877.52 ± 868.47 mL), and VCO2 (mean ± SD: 4301.27 ± 1001.07 mL). Similarly, measurements of chest circumference (mean ± SD: 91.40 ± 10.72 cm), MEP, and diaphragmatic circumference during inspiration (mean ± SD: 95.20 ± 10.21 cm) were significantly associated with VO2max (mean ± SD: 58.52 ± 10.74 mL/kg/min), while the remaining predictor variables did not demonstrate a significant effect on VO2max. Additionally, a multiple linear regression analysis was conducted to examine the combined effects of respiratory muscle strength and ventilatory factors on VO2max. The model, which included interaction terms, explained 89.9% of the variance in VO2max (R2 = 0.899, adjusted R2 = 0.859). Significant interactions were found between MIP and VE (B = −0.084, p = 0.006), as well as MEP and VE (B = 0.072, p = 0.012). These findings suggest that respiratory muscle strength plays a more substantial role in determining VO2max in individuals with higher ventilatory efficiency, highlighting the importance of both respiratory strength and breathing efficiency in aerobic performance. Our findings underscore the importance of considering respiratory muscle strength in assessing and enhancing athletes’ aerobic performance. Integrating objective measurements such as maximal inspiratory and expiratory pressure assessments into routine performance evaluations allows coaches and sports scientists to monitor changes in respiratory function over time and adjust training protocols accordingly.

Association of genomically enhanced residual feed intake with performance, feed efficiency, feeding behavior, gas flux, and nutrient digestibility in growing Holstein heifers.

Residual feed intake (RFI), a metric of feed efficiency, is moderately heritable and independent of body size and productivity, making it an ideal trait for investigation as a selection criterion to improve feed efficiency of growing cattle. The objective of this study was to examine the differences in performance, feed efficiency, feeding behavior, gas flux, and nutrient digestibility in Holstein heifers with divergent genomically enhanced breeding values for RFI (RFIg). Holstein heifers (n = 55; BW = 352 ± 64kg) with low (n = 29) or high (n = 26) RFIg were selected from a contemporary group of 453 commercial Holstein heifers. Heifers were rotated between 1 of 2 pens, each equipped with four electronic feed bunks and one pen with a GreenFeed gaseous exchange monitoring (GEM) system. Individual dry matter intake (DMI) and feeding behavior data were collected for 84-d. Body weight (BW) was measured weekly and spot fecal samples collected at weighing. Phenotypic RFI (RFIp) was calculated as the residual from regression of DMI on average daily gain (ADG) and mid-test metabolic BW (BW0.75). A mixed model including the fixed effect of RFIg classification and random effect of group was used to evaluate the effect of RFIg classification on response variables. There were no differences (P > 0.05) in BW and ADG for heifers with divergent RFIg; however, low RFIg heifers consumed 7.5% less (P < 0.05) feed per day. Consequently, low RFIg heifers exhibited a more favorable (P < 0.05) RFIp (-0.196 vs 0.222kg/d, respectively). Low RFIg heifers had 8.7% fewer (P < 0.05) bunk visit (BV) events per day and tended to have a 11.2% slower (P < 0.10) eating rate. Low RFIg heifers had 7.7% lower (P < 0.05) methane (CH4) emissions (g/d), 6.1% lower (P ≤ 0.05) carbon dioxide (CO2) production (g/d), and 5.6% lower (P ≤ 0.05) heat production (Mcal/d) than high RFIg heifers. However, CH4 yield and CO2 yield (g/kg DMI), and heat production per unit DMI (Mcal/kg DMI) did not differ (P > 0.05) between heifers with divergent RFIg. Dry matter and nutrient digestibility did not differ (P > 0.05) between heifers with divergent RFIg. Overall, heifers selected to be more feed efficient exhibited more favorable energy efficiencies and feed efficiency phenotypes. Results suggest that selection based on RFIg provides opportunities to select cattle with favorable feed efficiency phenotypes to increase the economic and environmental sustainability of the cattle industry.

Self-healing of cracks in cement-based materials through bio-mineralization of low air-dependency microorganisms

Microbial self-healing technology for concrete is attracting widespread attention due to its environmentally friendly, non-toxic, and sustainable attributes. Currently, microbial agents utilized in concrete exhibit a high dependence on atmospheric conditions, relying on atmospheric oxygen to activate or capture carbon dioxide from the air for the generation of carbonate ions. This paper introduces an innovative low-dependency microbial restorative aimed at augmenting the self-healing capability of concrete by nearly doubling the available carbonate ions and providing 80 % of them internally, especially targeting deep cracks. A pioneering approach was employed by combining microorganisms that rapidly produce carbon dioxide with those that expedite carbon dioxide hydration. Microbial functional components were meticulously pelletized to create core-shell structure restorative particles, featuring an outer protective layer constructed with low-alkali cement. This study investigates the mechanism through simulation and experimentation, including substrate conversion, carbon dioxide transformation, and the generation and accumulation of carbonate ions and calcium ions. Essentially, this research not only presents a path towards reduced atmospheric dependence but also provides valuable insights for comprehending the mechanism behind microbial self-healing concrete.

Relation Between Multiplication of Venous Carbon Dioxide Partial Pressure (PvCO2) and the Ratio of Gas Flow to Pump Flow (Ve/Q) with Hyperlactatemia During Cardiopulmonary Bypass.

The incidence of hyperlactatemia due to hypoperfusion during cardiopulmonary bypass (CPB) increases morbidity. Carbon dioxide production during CPB is one of the lactate production markers, in addition to other markers such as delivery oxygen (DO2), oxygen consumption (VO2), mixed vein oxygen saturation (SvO2), and oxygen extraction ratio (O2ER). This observational analytic study was conducted on 40 adult cardiac surgery patients using a CPB machine. Initial lactate is taken when entering CPB and final lactate is examined 15 min after coming off bypass. The values of DO2, VO2, SvO2, VCO2, respiratory quotient (RQ), DO2/VCO2, PvCO2 × Ve/Q were calculated from the results of blood and venous gas analysis 1 h after entering CPB in the nadir of core temperature and lowest pump flow. The multivariate test showed that the value of PvCO2 × Ve/Q was more effective than other oxygenation and carbon dioxide parameters in predicting an increase in the percentage of lactate. Each increase of 1 mmHg PvCO2 ×× Ve/Q can predict a final lactate increase of 29% from the initial lactate. The high PvCO2 × Ve/Q value is also the strongest correlation factor for the incidence of hyperlactatemia after CPB (final lactate >3 mmol/L). The cutoff value of this marker is >19.3 mmHg, which has a sensitivity of 100% and a specificity of 55.6% with a strong correlation value. The PvCO2 × Ve/Q value proved to be one of the significant markers in predicting hyperlactatemia during cardiac surgery using CPB.

Investigating Intumescent Flame-Retardant Additives in Polyurethane Foam to Improve the Flame Resistance and Sustainability of Aircraft Cabin Materials

Polyurethane (PU) foam has a high flammability and is widely used in aircraft interiors, presenting a significant danger to occupants. This study analysed three composite intumescent flame-retardant (IFR) coatings for flexible PU foam; expandable graphite (EG), ammonium polyphosphate (APP) and alginate (AG). The coatings were prepared in concentrations of 5 wt%, 10 wt%, and 50 wt% with an acrylic binder. The coated samples were characterised using cone calorimetry, SEM, and mechanical testing. The findings showed peak heat release rate, total heat release, and carbon dioxide production from the 10 wt% triple-layer coating (EG:APP:AG) was 52%, 32%, and 58% less than the PU control. The char of the 10 wt% triple-layer sample effectively suppressed smoke release and inhibited the transfer of fuel and gas volatiles. Mechanical testing demonstrated a 3.4 times increase in tensile strength and a 15.4 times increase in compressive strength (50% compression) compared to the control PU with the 10 wt% triple-layer coating. A fire dynamics simulator model was developed that demonstrated large-scale flammability modelling for commercial aircraft. Future work can explore the integration of IFR coatings into computational analysis. These new bio-based coatings produced promising results for aircraft fire safety and flammability performance for PU polymers.