Carbon Dioxide Output Research Articles

РОЛЬ ЛЕТКИХ КОМПОНЕНТІВ У ПРОЦЕСІ ТЕРМАЛЬНОЇ ДЕCТРУКЦІЇ ТА ЗАПАЛЮВАННЯ БІОМАСИ ЛУШПИННЯ СОНЯШНИКА

The final composition of volatile components in the process of oxidative pyrolysis depends on the temperature level of the process. The gas output increases with the growth of hydrogen, methane and heavy hydrocarbons concentration in the process of pyrolysis in the range of 200-500°C. In this case, there is a noticeable decrease in undesirable impurities in the output of carbon dioxide and nitrogen in the fuel gas. The obtained data on the dynamics of thermal decomposition of biomass under heating conditions reflect the complex dependence of the yield of total gas individual components both on time and on the temperature of the process. The more volatiles contained in the source fuel, (the other things being equal) the faster the gas mixture ignites, and the more intensely it burns out. The composition and temperature of the gas mixture affects the pressure drop and auto-ignition temperature in the pyrolysis chamber. It was found that the lowest self-ignition temperature of a gas mixture is 490°C. A series of experiments to determine the critical condition for self-ignition at a constant temperature of 490°C and various initial pressures of the mixture (100-300 kPa) was carried out. It was found that the transition from a smooth increase in pressure of 90 kPa to an explosive one (up to 300-400 kPa) depends on the composition and temperature of the gas mixture. Therefore, the composition of the gas and its ignition temperature can be controlled by adjusting the mode of pressure increase in the reactor.

Thermodynamic analysis of hydrocarbon reforming

A holistic hydrocarbon reforming analysis is performed using equilibrium calculations based on Gibbs energy minimization. The reforming feed composition is defined based on the oxygen to carbon atom ratio and the hydrogen to carbon atom ratio. The coke formation, carbon dioxide yield, and synthesis gas mole fraction were investigated to determine an operating composition region for hydrocarbon reforming while the hydrogen yield, hydrogen to carbon monoxide ratio, and the stoichiometric ratio were investigated to determine the reforming feed composition to produce hydrogen and optimal synthesis gas compositions for downstream processes. Our findings show that the synthesis of hydrogen via the reforming process will result in carbon dioxide emissions for any hydrocarbon feed. To produce the optimal synthesis gas for oxo-synthesis, Fischer-Tropsch synthesis and methanol synthesis, our findings show that reforming with methane provides the best opportunity for incorporation of carbon dioxide, while the reforming of coke does not result in the incorporation of carbon dioxide.

Spirometry has added value over electrodermal activity as a physiological marker of mental load in male subjects

The objective distinction of different types of mental demands as well as their intensity is relevant for research and practical application but poses a challenge for established physiological methods. We investigated whether respiratory gases (oxygen uptake and carbon dioxide output) are suitable to distinguish between emotional stress and cognitive load. To this end, we compared the application of spirometry with an established procedure, namely electrodermal activity (EDA). Our results indicate that electrodermal activity shows a strong responsivity to emotional stress induction, which was highly correlated with its responsivity to cognitive load. Respiratory gases were both sensitive and specific to cognitive load and had the advantage of being predictive for cognitive performance as well as self-reported emotional state. These results support the notion that respiratory gases are a valuable complement to common physiological procedures in the detection and discrimination of different mental demands.

Acute Effects of Esports on the Cardiovascular System and Energy Expenditure in Amateur Esports Players.

IntroductionEsports is practiced by millions of people worldwide every day. On a professional level, esports has been proven to have a high stress potential and is sometimes considered equivalent to traditional sporting activities. While traditional sports have health-promoting effects through muscle activity and increased energy expenditure, amateur esports could represent a purely sedentary activity, which would carry potentially harmful effects when practiced regularly. Therefore, this study aims to investigate the acute effects of esports on the cardiovascular system and energy expenditure in amateur esports players to show whether esports can be considered as physical strain or mental stress or whether amateur esports has to be seen as purely sedentary behavior.MethodsThirty male subjects participated in a 30-min gaming session, playing the soccer simulation game FIFA 20 or the tactical, first-person multiplayer shooter Counter-Strike: Global Offensive. Respiratory and cardiovascular parameters, as well as energy expenditure, blood glucose, lactate, and cortisol, were determined pre-, during, and post-gaming.ResultsThere were no significant changes in oxygen uptake, carbon dioxide output, energy expenditure, stroke volume, or lactate levels. Heart rate, blood glucose and cortisol decreased through the intervention until reaching their minimum levels 10 min post-gaming (Cortisolpre: 3.1 ± 2.9 ng/ml, Cortisolpost: 2.2 ± 2.3 ng/ml, p < 0.01; HRmin0.5: 82 ± 11 bpm, HRpost: 74 ± 13 bpm, p < 0.01).ConclusionA 30-min esports intervention does not positively affect energy expenditure or metabolism in amateur esports players. Therefore, it cannot provide the same health-promoting effects as traditional sports participation, but could in the long-term rather cause the same potentially health-damaging effects as purely sedentary behavior. However, it does not trigger a negative stress response in the players. Deliberate physical activity and exercise routines adapted to these demands should therefore be part of the daily life of amateur esports players.

A251 USE OF INDIRECT CALORIMETRY TESTING TO DIRECT NUTRITION SUPPORT IN CRITICALLY ILL PATIENTS WITH GASTROINTESTINAL CONDITIONS

BackgroundIndirect calorimetry (IC), which measures oxygen uptake and carbon dioxide output, determines energy expenditure (EE) more precisely than predictive equations in critically ill patients. It is unknown whether the use of IC affects energy provision in critically ill patients with gastrointestinal (GI) conditions that affect absorption and digestionAimsTo (1) compare IC and predictive equations for determining energy needs and (2) evaluate whether IC results affect changes in nutrition support in critically ill patients with GI conditions.MethodsIn a prospective, observational study, IC was performed for 25 to 55 mins in critically ill patients admitted to intensive care or clinical wards at 2 tertiary-care hospitals in Hamilton, Ontario between Feb 2018 to Sept 2021. EE measured by IC was compared to EE determined by a predictive equation (25 kcal/kg) or the Harris-Benedict (HB) formula. A change in energy provision was defined as a change of >10% directed by IC. Continuous data are expressed as means and standard deviation (SD), and categorical data as a proportion of patients. The Mann Whitney U Test (SPSSv26) was used to compare GI and non-GI populations.ResultsOf 296 IC tests in 229 patients, 39 of them were in 30 GI patients (11 female; mean age 62 yrs; SD 19). Admission GI diagnoses were pancreatitis (33%), liver disease (20%), Crohn’s disease/ autoimmune enteropathy (20%), post-bowel resection (10%), chronic abdominal pain (10%), and cholangitis (7%). The predictive formula underestimated EE in 67% of GI patients (mean deficit 503 kcal/day) compared to IC, corresponding to a mean deficit of 25% of patients’ energy needs. The HB formula underestimated EE in 73% of patients (mean deficit 652 kcal/day), a mean deficit of 28% of patients’ energy needs compared to IC. Pancreatitis was the majority diagnosis (75% of the predictive equation; 50% HB) among patients with the highest deficit (>30%) in energy needs when compared to IC. There were no significant differences in the rates of underestimation of energy needs based on predictive and HB formulas between the GI and non-GI patients or between luminal GI and non-luminal GI conditions. After IC, 63% of tests led to changes in energy provisions in GI patients; most requiring an increase in energy provisions (53%).ConclusionsThe use of IC to accurately measure EE led to changes in energy provisions in critically ill GI patients. Preventing over- and underfeeding with the implementation of IC to guide nutrition has the potential to improve outcomes in critically ill patients with gastrointestinal conditions.Funding AgenciesNone

Assessment of Carbon Dioxide Emissions due to Forest Fires in Russia and Possible Ways to Reduce Them

Calculations of CO2 emissions into the atmosphere caused by forest fires in Russia as well as an experimental assessment of some possibilities to reduce the emissions were carried out. It was shown that calculations with the usage of the average values of the reserves of combustible forest materials (CFM), the area of fires and the value of the mass rate of wood burning gives the same results as the approach based on the relatively accurate data on the reserves of CFM and their distribution over the fire area as well as an information on the character of forest fires. It was obtained experimentally that the continuous short-term supply of sprayed extinguishing liquid does not reduce but increases the yield of carbon dioxide due to the earlier termination of the flame burning and transition of the process to the smoldering regime. It is possible to reduce CO2 emissions into the atmosphere caused by forest fires up to 3-5 times when the extinguishing liquid is sprayed by applying two short-term pulses to eliminate both flaming and smoldering combustion.

Experimental and Theoretical Study of Gamma Radiolysis and Dose Rate Effect of o-Cresol Formaldehyde Epoxy Composites.

Gamma radiolysis behaviors and mechanisms of silica-filled o-cresol formaldehyde epoxy are studied at 2.20 × 10-5 to 1.95 × 10-1 Gy/s. The radiolysis-induced changes in chemical structures do not severely affect its thermostability. The slightly deteriorated mechanical strength at temperature exceeding 100 °C is accompanied by the declining glass transition temperature (from 185.9 to 172.2 °C) and enhanced damping ability. The gas yields of hydrogen, methane, and carbon dioxide manifest a remarkable dose rate effect. Based on the Schwarzschild law, their yields at an extremely low dose rate are accurately predicted by the established master curves. Besides, the latent radiolysis of gas products and postradiation effect are found with caution. The radiation-caused residual spin species are proved to be composed of silica defects and a phenoxy-type free radical with a tert-butyl group, according to the experimental results, theoretical calculations, and spectra simulations. The lower vertical ionization potential (7.6 eV) and adiabatic ionization potential (7.1 eV) are primarily due to the ionization of the benzene ring moiety with the tert-butyl group, which is likely to suffer from radiolysis. The calculated bond dissociation energy (260.8-563.5 kJ/mol) of the typical chemical bonds of epoxy is consistent with its radiolytic vulnerability and degradation mechanisms.

Characterization of historical leather bookbindings by various thermal methods (TG/MS, Py-GC/MS, and micro-DSC) and FTIR-ATR spectroscopy

The goal of this study was to obtain information about the thermal stability, composition and molecular structure of four historical leather bookbindings dated between the 17th and 19th century and to identify correlations between their thermal, structural and chemical properties and deterioration mechanisms by using thermal analysis and decomposition methods (TG/MS, micro-DSC, Py-GC/MS), and infrared spectroscopy (FTIR-ATR). The TG/MS study revealed that the maximum thermal decomposition rate of the historical samples depended on the deterioration degree of leather. Micro-DSC was applied to determine the collagen population profile, i.e., “leather-like”, “parchment-like”, or “gelatin-like” behavior, which characterizes the deterioration pattern of the samples. The historical samples have higher amount of adsorbed water compared with the modern leather indicating their higher polarity. The significantly higher yield of carbon dioxide during the pyrolysis of historical leathers demonstrates that leather underwent various oxidation processes over time. The smaller yield of the pyrolysis products attributed to vegetable tannins detected in the chromatograms of historical leathers was related to the degradation of tannins (i.e., de-tanning), while the higher amount of 2-pyrrolidone and succinimide confirmed the oxidation of proline and hydroxyproline amino acid residues in the historical leathers. Leather de-tanning and collagen gelatinization were clearly evidenced by both micro-DSC and FTIR-ATR.

Mild-to-moderate COVID-19 impact on the cardiorespiratory fitness in young and middle-aged populations.

The goal of the present study was to compare pulmonary function test (PFT) and cardiopulmonary exercise test (CPET) performance in COVID-19 survivors with a control group (CG). This was a cross-sectional study. Patients diagnosed with COVID-19, without severe signs and symptoms, were evaluated one month after the infection. Healthy volunteers matched for sex and age constituted the control group. All volunteers underwent the following assessments: i) clinical evaluation, ii) PTF; and iii) CPET on a cycle ergometer. Metabolic variables were measured by the CareFusion Oxycon Mobile device. In addition, heart rate responses, peak systolic and diastolic blood pressure, and perceived exertion were recorded. Twenty-nine patients with COVID-19 and 18 healthy control subjects were evaluated. Surviving patients of COVID-19 had a mean age of 40 years and had higher body mass index and persistent symptoms compared to the CG (P<0.05), but patients with COVID-19 had more comorbidities, number of medications, and greater impairment of lung function (P<0.05). Regarding CPET, patients surviving COVID-19 had reduced peak workload, oxygen uptake (V̇O2), carbon dioxide output (V̇CO2), circulatory power (CP), and end-tidal pressure for carbon dioxide (P ETCO2) (P<0.05). Additionally, survivors had depressed chronotropic and ventilatory responses, low peak oxygen saturation, and greater muscle fatigue (P<0.05) compared to CG. Despite not showing signs and symptoms of severe disease during infection, adult survivors had losses of lung function and cardiorespiratory capacity one month after recovery from COVID-19. In addition, cardiovascular, ventilatory, and lower limb fatigue responses were the main exercise limitations.

Comprehensive performance analysis and optimization of novel SCR-ORC system for condensation heat recovery

• An ORC system based on a novel condenser is proposed for condensation heat recovery. • The comprehensive performance of SCR-ORC system and novel condenser is analyzed. • Genetic algorithm is implemented using optimum combination weights method. • Optimized parameters guarantee excellent comprehensive performance. • Thermodynamic, economic, and environmental performances are improved simultaneously. An organic Rankine cycle (ORC) system with separation, compression, and recycling of exhaust gas (SCR-ORC) based on a novel condenser is proposed. The relationship between volume, temperature, and pressure in fluid mechanics is used to change the internal space structure of condenser, so that a temperature difference is generated between the exhaust gas split in two spaces, which is used to recover the condensation heat. Then, the SCR-ORC system is used to reuse the recovered condensation heat. Further, the comprehensive performance of SCR-ORC system and novel condenser is analyzed and compared with that of ORC system and traditional condenser. Furthermore, multi-objective optimization is conducted by using thermodynamic, economic, and environmental performance as optimization objectives through the genetic algorithm with optimal combination weights method. The results indicate that when the condenser pressure drop (Δ P c ) is 0.12 MPa, the waste condensation heat of traditional condenser reaches 64852.24 kW, while that of novel condenser is 38910.92 kW, the condensation heat recovery and exergy loss of novel condenser are 6114.28 kW and 2408.63 kW respectively. Compared with the ORC system, the net power output ( W net ), thermal efficiency ( η t ), exergy efficiency ( η ex ), and annual emission reduction ( AER ) of equivalent carbon dioxide of SCR-ORC system with R245fa as the working fluid are increased by 6803.17 kW, 2.52%, 6.54%, and 1215.82 × 10 3 kg, respectively, while the payback period ( PBP ) is decreased by 0.59 years. It is also found that the working fluids with lower critical temperature exhibit better comprehensive performance, and the comprehensive performance of R134a is the highest among the considered working fluids.

Origin of inorganic carbon dioxide associated with hydrocarbon generation: Evidence from hydrous pyrolysis experiments and natural and shale gases

Inorganic carbon dioxide with heavier δ13C values frequently occurs in natural gases or shale gases generated from marine source rocks. To provide a better understanding on the origin of inorganic CO2 associated with hydrocarbon generation, hydrous pyrolysis experiments were conducted utilizing source rocks of different depositional environments and varying carbonate mineral concentrations, at a fixed temperature 350 °C, and lithostatic pressure 50 MPa and fluid pressure 28 MPa for 48 h. Carbon dioxide yields, concentrations in gaseous products, and δ13C values tend to increase in proportion to the carbonate mineral concentrations of the original source rocks. The results showed that carbonate mineral dissolution might be the principal source of inorganic carbon dioxide generated in the experiments. Based on the δ13C values of carbon dioxide produced in the hydrous pyrolysis experiments both in this study and in the literature, we suggest that inorganic CO2 show δ13C values heavier than −8‰, organic CO2 show δ13C values lighter than −16‰, and CO2 with mixed origins show δ13C values ranging from −16 to −8‰. We further discussed the origins of CO2 in the marine Ordovician natural gases of the Ordos Basin, in the marine Miocene CO2-dominated natural gases of the Yinggehai Basin, and in the marine Silurian shale gases of the Sichuan Basin. With a majority of δ13C values higher than −8‰, a major inorganic origin from carbonate mineral dissolution were suggested for CO2 in the natural and shale gases of the above basins.

Innovative ways to control dust and explosion safety of mine workings

Ensuring dust and explosion safety during underground coal mining is one of the most important tasks of industrial safety and labor protection departments. The main method of preventing explosions of coal dust settled in mine workings is to process them with stone dust (rock dusting). The traditional methods of quality control of rock dusting include radioisotope, optical and chemical methods. To implement them, the devices are equipped with environmentally harmful radioactive elements, expensive optical sensors, desiccants and replaceable flasks with chemical reagents, which increases the cost of analysis and its duration. The measurement error of these devices is 10 % or more. The main purpose of the study is to develop and substantiate a new method for monitoring the dust and explosion safety of mine workings, which will be devoid of the disadvantages of the methods mentioned above. It is proposed to evaluate the quality of rock-dust distribution by a fundamentally new way – thermogravimetric. The method was tested on the dust of coal mines in Kuzbass and the Vorkuta basin, including dust samples taken in mines with actual explosions. The article presents the results of experimental studies of the processes of thermal destruction of coal and stone dust mixtures. The non-overlapping intervals of the thermogravimetric reaction are identified: moisture yield (35-132 °С); volatile matter yield from coal (380-580 °С); thermal degradation of limestone with carbon dioxide yield (650-850 °С). Methods and mathematical dependencies for processing significant and qualitative identification characteristics of thermogravimetric curves in determining the content of non-combustible components in a sample of mine dust are considered.

MXene based core-shell flame retardant towards reducing fire hazards of thermoplastic polyurethane

Amounts of heat and toxic fumes are released during the combustion of polymeric materials, which severely threats to the human health and causes the environmental pollution. Therefore, it is vital to find an effective way to address these problems. Herein, titanium carbide (Ti 3 C 2 T x ) and chitosan (CS) were firstly adopted to functionalize ammonium polyphosphate (APP) via the microencapsulation and layer-by-layer assembly. Afterwards, the as-synthesized core-shell-structured hybrid (APP@CS@Ti 3 C 2 T x ) was used to enhance the interface compatibility, thermal stability and fire safety of thermoplastic polyurethane (TPU) composites. The results demonstrated that the APP@CS@Ti 3 C 2 T x hybrid presented a strong interface interaction with the TPU matrix. Besides, TPU/APP@CS@Ti 3 C 2 T x composites exhibited the improved thermal stability. The TPU composite containing 9.5APP@CS@0.5Ti 3 C 2 T x achieved V-0 rating in the UL-94 testing. The cone calorimetry results illustrated that introduction of 9.5APP@CS@0.5Ti 3 C 2 T x into TPU caused remarkable reduction in the total heat release (73.0%) and total smoke release (77.3%). Furthermore, the total carbon monoxide yield and total carbon dioxide yield of TPU/9.5APP@CS@0.5Ti 3 C 2 T x were significantly decreased by 75.3% and 75.3%, respectively, compared to those of pure TPU. The synergistic charring effect between APP@CS and Ti 3 C 2 T x , the thermal oxidization action and “tortuous path” effect of Ti 3 C 2 T x nanosheets combined with the trapping effect of APP@CS resulted in the dramatically improved fire resistance of the polymeric material. This work offers an innovative strategy to fabricate the high-performance polymer composites with superior fire safety.

Breathing patterns in people with exercise-induced laryngeal obstruction.

Exercise‐induced laryngeal obstruction (EILO) is common, but we lack readily available diagnostic tools. The larynx represents an important point of resistance in the airways, and we therefore hypothesized that EILO is associated with characteristic breathing patterns possible to record from a standard incremental ergospirometry test. We studied 24 individuals with moderate/severe EILO and 20 individuals with no‐EILO, mean (SD) age 17 (6.1) and 24 (6.4) years, respectively. EILO versus no‐EILO was verified from maximal continuous laryngoscopy treadmill exercise (CLE) tests, which also included ergospirometry. We described the relationships between minute ventilation (V˙E) versus tidal volume (V T) and V˙E versus carbon dioxide output (V˙CO2), using respectively quadratic and linear equations, and applied adjusted regression models to compare ergospirometry data and curve parameters. Compared to the no‐EILO group, the group with EILO had prolonged inspiratory time (T in), lower breathing frequency (B f), lower V˙E, and lower inspiratory flow rate (V˙in) at peak exercise. Mathematical modeling of the breathing pattern relationships was feasible in both groups, with similar coefficients of variation. For V˙E versus V T, the mathematical curve parameters were similar. For V˙E versus V˙CO2, the slope was similar but the intercept was lower in the EILO group. EILO was associated with prolonged T in, lower B f, V˙E, and V˙E. The relationship between V˙E versus V T was similar, whereas for V˙E versus V˙CO2, the slope was almost parallel but shifted downward for the EILO group. Most ergospirometry data overlapped, except V˙in which discriminated between EILO and no‐EILO in a promising way.

Comprehensive Study of Heart Rate Recovery and Altered Ventilatory Response to Exercise in Patients with Obstructive Sleep Apnea

Abstract Background Obstructive sleep apnea (OSA) is a chronic disorder that results in many cardiovascular disorders including hypertension, arrhythmias and congestive heart failure (CHF). Polysomnography is the gold standard for diagnosis of OSA, even though up to 93% of women and 82% of men with moderate to severe OSA still remain undiagnosed. Cardiopulmonary exercise testing (CPXT) has been conventionally used for evaluation of coronary artery diseases and rehabilitation of cardiac patients. Modern systems allow for the analysis of gas exchange at rest, during exercise, and during recovery and also yield measures of oxygen uptake (V O2), carbon dioxide output (V CO2), and minute ventilation (V E) together with heart rate, blood pressure, electrocardiography findings, and symptoms. This may have clinical utility if added to the available screening tools used to identify OSA. Aim of study To assess altered ventilatory response and heart rate recovery in response to exercise in patients with obstructive sleep apnea and their relation to its severity. Methods and Results Case control study was enrolled including 30 patients with obstructive sleep apnea (OSA) divided according to severity (5 mild, 8 moderate and 17 severe) and 15 control healthy overweight with sedentary lifestyle individuals. The two groups underwent cardiopulmonary exercise testing and different pulmonary and cardiac parameters were calculated. Greater VE, VE/VCO2, VE/VO2 ratios and VE/VCO2 slope were statistically significant regarding the patients group (P &amp;lt; 0.001, F = 69.053, 104.381, 140.806 and 68.010 respectively according to ANOVA test). OSA patients had a reduced maximal exercise capacity expressed as lower VO2 peak, decreased breathing reserve (BR) and VO2 at anaerobic threshold compared to control group (P &amp;lt; 0.001, F = 22.597, 68.773 and 82.90 respectively). Delayed heart rate recovery (HRR) and weaker chronotropic response (CR) in patients with OSA than in controls with negative relationship to severity of OSA were proved (p &amp;lt; 0.001, F = 119.493 and 91.271 respectively). The study revealed elevated maximal systolic BP (max SBP), diastolic BP (max DBP) and recovery SBP in the following 2 minutes after exercise in patients with OSA relative to their healthy controls with positive relationship to the severity of OSA (P &amp;lt; 0.001, F = 37.129, 169.275 and 244.609 respectively). Conclusion Patients with OSA demonstrated exaggerated ventilatory response to exercise and autonomic dysfunction reflected by measurement of heart rate variability and reduced maximal exercise capacity than healthy controls. Abbreviations OSA, CHF, CPXT, VO2, VCO2, VE, VE/VCO2, VE/VO2, VE/VCO2, BR, CR, HRR, max SBP and max DBP.

Thermocatalytic oxidation of a three-component mixture of volatile organic compounds by a titanium dioxide-supported platinum catalyst

To gain a better knowledge for efficient treatment of volatile organic compounds (VOCs), a series of experiments were carried out to assess the potential of titanium dioxide (TiO2)-supported platinum (Pt) catalyst (Pt/TiO2) in low-temperature catalytic oxidation of formaldehyde (FA), acetaldehyde (AA), and toluene (T) (10–100 ppm range) both individually and as a mixture. Accordingly, 100% mineralization of FA (50–200 ppm), AA (10 ppm), and T (10 ppm) was achieved by 1%-Pt/TiO2-R (‘R’ suffix for reduction pretreatment on the catalyst) at 30, 190, and 160 °C, respectively. The carbon dioxide (CO2) yield was used to assess the extent of VOC mineralization in air (as the carrier gas at a flow rate of 0.2 L atm min ̶ 1). Their conversion efficiency was lowered with increases in the pollutant concentration or decreases in the bed mass. Furthermore, the reaction intermediates and catalytic pathways were assessed based on in-situ diffuse reflectance infrared Fourier transform spectroscopy. This study offers valuable insights into the interactive roles between process variables in the low-temperature thermocatalytic oxidation of single and/or multi-component gaseous VOC systems and into the effects of such variables on the overall catalytic performance.

PeakPETCO2 combined with FEV1/FVC predicts vasodilator-responsive patients with idiopathic pulmonary arterial hypertension.

Cardiopulmonary exercise testing and pulmonary function test are important methods for detecting human cardio-pulmonary function. Whether they could screen vasoresponsiveness in idiopathic pulmonary artery hypertension (IPAH) patients remains undefined. One hundred thirty-two IPAH patients with complete data were retrospectively enrolled. Patients were classified as vasodilator-responsive (VR) group and vasodilator-nonresponsive (VNR) group on the basis of the acute vasodilator test. Pulmonary function test and cardiopulmonary exercise testing were assessed subsequently and all patients were confirmed by right heart catheterization. We analyzed cardiopulmonary exercise testing and pulmonary function test data and derived a prediction rule to screen vasodilator-responsive patients in IPAH. Nineteen of VR-IPAH and 113 of VNR-IPAH patients were retrospectively enrolled. Compared with VNR-IPAH patients, VR-IPAH patients had less severe hemodynamic effects (lower RAP, m PAP, PAWP, and PVR). And VR-IPAH patients had higher anaerobic threshold (AT), peak partial pressure of end-tidal carbon dioxide (PETCO2), oxygen uptake efficiency (OUEP), and FEV1/FVC (P all <0.05), while lower peak partial pressure of end-tidal oxygen (PETO2) and minute ventilation (VE)/carbon dioxide output (VCO2) slope (P all <0.05). FEV1/FVC (Odds Ratio [OR]: 1.14, 95% confidence interval [CI]: 1.02–1.26, P = 0.02) and PeakPETCO2 (OR: 1.13, 95% CI: 1.01–1.26, P = 0.04) were independent predictors of VR adjusted for age, sex, and body mass index. A novel formula (=−16.17 + 0.123 × PeakPETCO2 + 0.127×FEV1/FVC) reached a high area under the curve value of 0.8 (P = 0.003). Combined with these parameters, the optimal cutoff value of this model for detection of VR is −1.06, with a specificity of 91% and sensitivity of 67%. Compared with VNR-IPAH patients, VR-IPAH patients had less severe hemodynamic effects. Higher FEV1/FVC and higher peak PETCO2 were associated with increased odds for vasoresponsiveness. A novel score combining PeakPETCO2 and FEV1/FVC provides high specificity to predict VR patients among IPAH.

Exertional ventilation/carbon dioxide output relationship in COPD: from physiological mechanisms to clinical applications.

There is well established evidence that the minute ventilation (V'E)/carbon dioxide output (V'CO2 ) relationship is relevant to a number of patient-related outcomes in COPD. In most circumstances, an increased V'E/V'CO2 reflects an enlarged physiological dead space ("wasted" ventilation), although alveolar hyperventilation (largely due to increased chemosensitivity) may play an adjunct role, particularly in patients with coexistent cardiovascular disease. The V'E/V'CO2 nadir, in particular, has been found to be an important predictor of dyspnoea and poor exercise tolerance, even in patients with largely preserved forced expiratory volume in 1 s. As the disease progresses, a high nadir might help to unravel the cause of disproportionate breathlessness. When analysed in association with measurements of dynamic inspiratory constraints, a high V'E/V'CO2 is valuable to ascertain a role for the "lungs" in limiting dyspnoeic patients. Regardless of disease severity, cardiocirculatory (heart failure and pulmonary hypertension) and respiratory (lung fibrosis) comorbidities can further increase V'E/V'CO2 A high V'E/V'CO2 is a predictor of poor outcome in lung resection surgery, adding value to resting lung hyperinflation in predicting all-cause and respiratory mortality across the spectrum of disease severity. Considering its potential usefulness, the V'E/V'CO2 should be valued in the clinical management of patients with COPD.

Evaluation of Fischer-Tropsch synthesis to light olefins over Co- and Fe-based catalysts using artificial neural network

Currently, energy transition due to fossil fuel negative side effects is taking place. This transition impacts the chemical industry based on light olefins reactions. Plastics, detergents, polymers, and others are mostly produced from such hydrocarbons, which are mainly originated from oil-based and highly energy-consuming processes. Fischer-Tropsch Synthesis (FTS) is a strategic technology capable to transform a given carbon source, including natural gas and biomass, into high added-value hydrocarbons. It is affected by several conditions, such as catalyst design and operating conditions and its feasibility requires a good selection of relevant process variables to optimize light olefins yield. In this work, Machine Learning models were used to predict adequate reaction conditions from the catalytic literature data. Three-layer feedforward neural networks were adjusted using a careful selection of operating conditions and catalyst composition as inputs and carbon monoxide conversion, light olefins selectivity, and carbon dioxide yield as outputs. The results indicate neural network prediction efficacy for FTS most relevant variables, such as temperature and catalyst composition. This work presents the novelty of including more variables in the model compared to recent similar studies, such as catalyst support, active phase, and promoters as inputs; and light olefins selectivity and CO2 yield as outputs. Overall, Fe-based catalyst (standard Fe (1.6 wt%) K/TiO2) presented the highest light olefins selectivity and yield at optimal conditions (T = 500 °C and 20 wt% of active phase), despite showing the highest emission of carbon dioxide.

Economical and preferred walking speed using body weight support apparatus with a spring-like characteristics

BackgroundA specific walking speed minimizing the U-shaped relationship between energy cost of transport per unit distance (CoT) and speed is called economical speed (ES). To investigate the effects of reduced body weight on the ES, we installed a body weight support (BWS) apparatus with a spring-like characteristics. We also examined whether the 'calculated' ES was equivalent to the 'preferred' walking speed (PWS) with 30% BWS.MethodsWe measured oxygen uptake and carbon dioxide output to calculate CoT values at seven treadmill walking speeds (0.67–2.00 m s− 1) in 40 healthy young males under normal walking (NW) and BWS. The PWS was determined under both conditions on a different day.ResultsA spring-like behavior of our BWS apparatus reduced the CoT values at 1.56, 1.78, and 2.00 m s− 1. The ES with BWS (1.61 ± 0.11 m s− 1) was faster than NW condition (1.39 ± 0.06 m s− 1). A Bland-Altman analysis indicated that there were no systematic biases between ES and PWS in both conditions.ConclusionsThe use of BWS apparatus with a spring-like behavior reduced the CoT values at faster walking speeds, resulting in the faster ES with 30% BWS compared to NW. Since the ES was equivalent to the PWS in both conditions, the PWS could be mainly determined by the metabolic minimization in healthy young males. This result also derives that the PWS can be a substitutable index of the individual ES in these populations.